Document 71VQkv4DNJOdV2V015323ypE8

ST. LOUIS PUBLIC LIBRARY ~7 American Society of Heating and Air-Conditioning Engineers Heating ventilating air conditioning guide. VOL 37 19 American Society of Heating Refrigerating and Air Conditioning Engineers. St 628.8 AMERICAN 210 50 47300 OVUITJUJ---- ' Heating s nd Air ConIditioninj Engineers fl 6 8 316 4 This Book Stoll Not Be Taken From The Library. Heating Ventilating Air Conditioning GUIDE 1959 d Applied Science DepL Heating Ventilating Air Conditioning GUIDE 1959 An Instrument of Service Prepared for the Profession containing A TECHNICAL DATA SECTION of reference material on the DESIGN AND SPECIFICATION OF RELATING, VENTILATING, AND AIR-CONDI TIONING SYSTEMS BASED ON--THE TRANSACTIONS--rTHE INVESTIGATIONS of the Research Laboratory and Cooperating Institutions-- and the Practice of the Members and Friends of the Society; A MANUFACTURERS' CATALOG DATA SECTION containing essential and reliable Information concerning Modern Equip ment; COMPLETE INDEXES to Technical and Catalog Data Sections.' ; : : :: - `' , ; [' ` :vi Vol. 37 $12:00 per copy PUBLISHED ANNUALLY BY THE American Society of Heating and < /< AlR-CONDmONING ENGINEERS, INC. 62 WORTH ST., NEW YORK 13, N. Y. A683164 Copyright 1959 BY THE American Society of heating and Air-Conditioning Engineers, Inc. AND BY IT Dedicated To the Advancement of The Profession and Its Allied Industries . TEXT AND ILLUSTRATIONS ARE FULLY PRO TECTED BY COPYRIGHT AND NOTHING THAT APPEARS MAY BE REPRINTED EITHER WHOLLY OR IN PART WITHOUT SPECIAL PERMISSION. Printed and Bound by Waveblt Press, Inc. BALTIMORE MARYLAND s af-r PREFACE TO THE 37th EDITION The Heating Ventilating Air Conditioning Guide, 1959, has been enlarged to 8K x 11 inch page size for the purpose of providing additional space for Dew technical text and for enlargement of many il lustrations, working charts, and tables. The use of larger type and open spacing in tables will be of par ticular advantage, for instance, in selecting heat transfer coefficients for various types of building construction or finding degree days for various cities. This edition has 286 new or revised diagrams and charts. In most cases the enlarged page size has made it possible to place illustrations very close to their first mention in the text. Five new chapters have been added on the follow ing subjects: (1) high-temperature water systems, (2) the heat pump, (3) evaporative apparatus for heat rejection, (4) evaporative air cooling and humidifica tion, and (5) snow melting. Outstanding improvements made in chanters con tinued from the previous edition include (1) new out door winter design temperatures based on probability of occurrence of various temperatures, (2) new steam pipe sizing charts and tables based on Moody friction data for steam flow, (3) a revised table on gages and construction of air ducts including low-, medium-, and high-pressure ducts, (4) revised information and illustrations for unit ventilators and their applica tion, (5) a rewritten chapter on automatic control with new illustrations of control applications, (6) general revision of the information on sorbents; in cluding their use at elevated pressures, (7) data oo heat transfer coefficients for ventilated attics, (8) revised information on sound absorption in ducts and plenums, noise levels, and diffuser noise, (9) up-todate values for maximum allowable concentration of contaminants in occupied spaces, (10) a new section on the absorption refrigeration system, (11) a new section on the gas-fired year-round residential air con ditioner, (12) new data on duct construction for resi dences, (13) a revised discussion of fuel utilization, efficiency, and consumption, (14) a rewritten chapter on school systems, and (15) additions and changes in the list of codes and standards. More detailed information regarding the changes io the various chapters: Chapter 7--Air Contaminanta. Additions and re visions have been made in the tables of maximum allowable concentration of toxic gases, vapors, dusts, fumes, and mists, in order to have these values con form to those adopted by the American Conference of Governmental Industrial Hygienists in 1958- Chapter 9--Heat Transmission Coefficients of Build ing Materials. A section on ventilated attic coeffi cients, with examples, has been added. The section on the practical use of overall coefficients has been re vised. The tables of heat transmission coefficients for various building constructions have been enlarged to facilitate their use. All wall and roof constructions have been numbered to aid in identifyingand referring to the coefficient for a particular construction. Chapter 10--Moisture in Building Construction. The information on moisture migration and its calcu lation has been revised. The discussion of condensa tion in cooled structures has been extended- Chapter It--Heating Load. The data on winter out door temperatures have been revised to show as de sign values for the United States the minimum aver age daily temperatures that have the probability of occurring once in 40, 20, 13, 10, or 5 years as deter mined from U. S. Weather Bureau records. The dis cussion of design temperatures has been rewritten to explain the use of these new values. The tables have been enlarged in type and size for easier readability. Chapter IS--Unit Ventilators and Unit Heaters. The discussion of unit ventilators has been enlarged and thirteen new illustrations have been added. The illustrations of piping connections to unit' heaters have also been revised. Chapter 16--Unitary Air-Conditioning Equipment. A section discussing the features, design considera tions, selection, ana installation of room air condi tioners has been added. Chapter 17--Electric Heating. This chapter was re written to include information on present heating units and methods of use. Chapter IS---Warm Air Heating Systems. The infor mation on ducts has been revised to include recom mended gages for residential systems. Chapter tO--Air Distribution- The sections on prin ciples of air distribution and on ventilating jets nave been rewritten and simplified. . Chapter tl--Air Duct Design- A revised section on construction includes data on high-, medium-, and low-pressure ductwork, coordinated with the recom mendations of the Sheet Metal and Air Conditioning Contractors National Association. The charts for frictioQ loss in ducts and the table of equivalent sizes of round and rectangular ducts have been enlarged. Chapter tS--Sound Control. Data on noise levels in offices have been added. The section on noise from axial-flow fans has been enlarged. New information is given oo diffuser noise. The sections on sound at tenuation in ducts and plenum absorption have been revised. Chapter 26--Steam Heating Systems. The informa tion oo steam pipe sizing has been rewritten to include a new basic chart (0 to 200 psig) based on the Moody' friction data which take into account the Reynolds umber and its effect on the friction factor, and to include also new charts for 30. 50, 100, and 150 psig and tables for 3.5 and 12 psig. (The new information, charts, and tables were prepared by the ASHAE Research Laboratory under the direction of the Tech nical Advisory Committee on Hot Water and Steam Heating.) The section on pressure-reducing valves has been enlarged by the addition of information formerly given in the chapter on District Heating. ' Chapter 28--Hot Water Heating Systems. A new chart for available gravity head has been added. Chapter 29--High-Temperature Water Systems. A new chapter has been adaed giving a general idea of the principles and practices that apply to high-tempierature systems and discussing significant considera tions for designing these systems. Many new illustra tions showing piping arrangements were used. Chapter 84--Automatic Fuel-burning Equipment. There has been a general revision of this chapter to bring the information up-to-date. A new chart for calculating friction drop or capacity for gas flow in piping has been added. Chapter 86--Healing Boilers, Furnaces, and Space Heaters. The data on steel boilers have been improved and enlarged. . Chapter 87---Estimating Fuel Consumptionfor Space Heating. The former section on seasonal efficiency has been replaced by a new section on Efficiency of Utili zation and the section on Calculated Heat Loss Method has been rewritten. Chapter 88--Refrigeration. The information on ab sorption systems been revised and new illustra tions have been added. Chapter 59--The Heat Pump. This is a new chapter giving information on the fundamentals, types, com ponents, performance, design, and selection of heat pumps. Chapter 40--Evaporative Apparatus for Heat Rejec tion. This is a new chapter giving information on water-cooling methods and equipment. Cooling tower theory, design, selection, operation, and maintenance are discussed. New data on spray performance are in cluded. Chapter +1--Evaporative Air Cooling and Humidifi cation. This is a new presentation of the operation of air washers and their use for humidification and de humidification. New information is given on evapora tive cooling, types of equipment, and design metnods. Several new illustrations were used. Chapter --Dehumidificaiion by Sorbent Materials. This chapter haw been rewritten to include current information on solid and liquid sorption systems. A new section has been added on use of sorbents at ele vated pressures. New illustrations were included. Chapter 45--Automatic Control. This chapter was rewritten and enlarged to include 18 new cuts showing application of controls for various operations. The description of control types and operation has been extended. Chapter 44--Instruments and Measurements. This chapter has been brought up to date by extensive revision. Chapter 4d--Motors and Motor Controls. Hie section on classification of motors has been revised to indicate the nomenclature adopted by the National Electric Manufacturers Association. Chapter 48--Residential Summer Air Conditioning. A new section on gas-fired year-round air conditioners has been added. Chapter 47--School Systems. This chapter has been rewritten with emphasis on factors affecting the heat ing and cooling loads. Various types of heating, cool- - mg, and ventilating systems are discussed. Chapter 48--Transportation Air Conditioning. The section on control of passenger bus air conditioning has been revised. Chapter 49--Snow Melting. A new chapter has been added giving a method of designing snow-melting sys tems. New tables and data are included. Chapter 58--Corrosion and Water-formed Deposits, Causes and Prevention. The section on use of resistant metals has been improved. Chapter 56--Water Services. The charts for friction loss have been enlarged. The section on electric water heating has been transferred to this chapter from the chapter on electric heating. Chapter 57--Codes and Standards. Several new standards have been added' and the correct editions of listed standards have been indicated. . In addition to the changes in specific chapters out lined, numerous improvements nave been made in both text and illustrations. A complete index to Technical Data is contained in a 16-page section at the front of Tub Guide. For convenient reference to equipment to be se lected for various types of installations, this book contains a Catalog Data Section showing products of 309 manufacturers of heating, ventilating, cooling, and air-conditioning equipment. This section is preceded by a 16-page index listing equipment available un der numerous headings for most convenient use. The Guide Committee is pleased to give credit for Preparation of Guide material for this edition to the ASHAE Technical Advisory Committees, particu larly those on Evaporative Cooling, Heat Pump, Heating and Air-Conditioning Loads, Hot Water and Steam Heating, Insulation, and Sorption. The staff of the ASHAE Research Laboratory has rendered valu able assistance to these committees. Many trade asso ciations, engineering societies, and other organiia- P. R. Achenbach E. R. Ambrose R. S. Ash G. C. F. Asker D. R. Baker G. L. Biehn ' William Bingham R. L. Botd, Jr. A. D. Brandt G: F. Carlson J. ft. Cahholl C. A. Carter J. B. Chaddock D. N. Cbosthwajt, Jr. L. F. Christowesson J. H. Clarks ' S. F. Duncan H. S. Dutches F. R. Ellenbsbger R. B. Engdahl L. F. Flagg W. F. Friend L. R. Fuller R. S. Funk Albert Giannini E. W. GiWORD H. T. Gilket E. A. Greenlee C. A. Gustafson E. G. Hansen W. S. Harris J. M. Hartman H. G. Hats H. R. Reiplb N. E. Hill tions mentioned in the text, in addition to individual engineers, both Society members and aoomembers, have contributed new material or reviewed present material to establish its authenticity. While it'is im possible to recognise all sources of information and help, the Guide Committee is pleased to mention the following, who have been very active in preparation of this volume: t W. O. Hoebneb C. M. Humphreys Leo Hungbbford N. J. Janisse F. A. Jot C. F. Katan G. A. Kelley W. F. Krbka W. B. Kirk J. L. Kline J. D. Kbobkeb H. R. Limbacheb R. Lisbon R. A. Locke R. D. Madison W. L. McGrath S. W. Miller J. T. Muller W. M. Mtlbb, Jr. Eugene O. Olbos C. H. Pbstehfield C. W. Pollock C. F. Pridmore T. F. Rockwell J. R. Schreiner C. G. Seqeler J. E. Seitbb Clifford Stbock B. L. Sturdbvant E. R. Teske H. C. S. Thom J. M. van Nibukerken P. N. VlNTHBB G. D. WlNANS V. D. WlSSMILLER The Guide Committee takes pleasure in presenting which should make the book more valuable than any to the Society this 1959 volume in its new format, preceding edition to its users. W. P. Chapman R. C. Cbewning J. R. Duncan GUIDE COMMITTEE H. W. Altea, Chairman R- A. Gonzalez " N. B. Hutcheon M. W. Keyes Carl H. Funk, Technical Secretary R. L. Maker D. W. Nelson E. F. Snyder, Jr., Ex-Officio vi CONTENTS . Page TITLE PAGE..... ....... ........................................'.................................................... Hi PREFACE............................... ......................................... ....................................... * INDEX TO TECHNICAL DATA........ ................................................................. u SECTION I. FUNDAMENTALS , Chapter 1. Terminology.................... 2. Abbreviations,Symbols, Conversion Factors...................................... 3. Thermodynamics........................................................................................................ 4. Fluid Flow.................................................................................................................. 5. Heat Transfer............................................................................................................. 1 7 13 35 47 SECTION II. ENVIRONMENT, COMFORT, AND PHYSIOLOGICAL PRINCIPLES Chapter 6. Physiological Principles................. ..... ........................................................ ' 7. Air Contaminants..................................................................................................... . 8- Air Conditioning in the Prevention and Treatment of Disease...................... 61 73 83 SECTION III. HEATING AND COOLING LOADS _ Chapter 9. Heat Transmission Coefficients of Building Materials..................................... 10. Moisture in Building Construction.................................................................... 11. Infiltration and Ventilation.................................................................................... 12. Heating Load......................................................................................................... . 13. Cooling Load.............................................................................................................. 93 127 139 151 167 SECTION IV. ROOM HEATING AND COOLING METHODS AND EQUIPMENT Chapter 14. Radiators, Convectors, Baseboard and Finned-Tube Units........................ 15. Unit Ventilators and Unit Heaters.............................'........................................ 16- Unitary Air-Conditioning Equipment.................................................................. 17. Electric Heating..................................................................................... 207 213 223 231 SECTION V. AIR SYSTEMS AND EQUIPMENT Chapter 18. Warm Air Heating Systems..................................................................................... 19. Central Systems for Air Conditioning.................................................................. 20. Air Distribution............................................................................................... 21. Air Duct Design........................................................................................................ 22. Fans.............................................................................................................................. 23. Air Heating and Cooling Coils............................................................................... 24. Air Cleaning................................................................................... 25. Sound Control............................................................................................................ 237 259 267 283 303 313 323 335 SECTION VI. STEAM AND WATER SYSTEMS AND EQUIPMENT Chapter 26. Steam Heating Systems........................................................................................... 27. District Heating........................................................................................................ 28. Hot Water Heating Systems................................................................................... 29. High-Temperature Water Systems........................................................................ 30. Panel Heating............................ 31. Pipe, Fittings, Welding..............................-............................................................. 32. Pipe and Industrial Insulation............................................................................... 355 383 391 409 419 435 453 vii ` CONTENTS (Concluded) . Page SECTION VII. HEAT GENERATING METHODS AND EQUIPMENT Chapter 33. Fuels and Combustion:........................................................................................... 467 34. Automatic Fuel-Burning Equipment.................................................................... 485 35. Heating Boilers, Furnaces, Space Heaters........................................................... 501 36. Chimneys and Draft Calculations........................................................................ 515 . 37. Estimating Fuel Consumption for Space Heating............................................. 527 SECTION VIII. REFRIGERATION, SPRAY APPARATUS, AND SORBENTS ' - Chapter 38. Refrigeration.................................. :.......................................................................... 39. The Heat Pump......................................................... 40. Evaporative Apparatus for Heat Rejection......................................................... 41. Evaporative Air Cooling and Humidification...................................................... 42. Dehumidification by Sorbent Materials............................................................... 541 663 579 591 601 SECTION IX. CONTROLS, INSTRUMENTS, AND MOTORS Chapter 43. Automatic Control.................................................................................................... 44. Instruments and Measurements............................................................................. 45. Motors and Motor Controls.................................................................................... 609 627 639 SECTION X. SPECIFIC APPLICATIONS Chapter 46. Residential Summer Air Conditioning................................................................. 47. School Systems........................................................................................................... 48. Transportation Air Conditioning........................................................................... 49. Snow Melting............................................................................................................. 651 657 663 671 SECTION XI. INDUSTRIAL SYSTEMS Chapter 50. Process and Product Air Conditioning................................................................. 51. Control of the Industrial Environment................................................................ 52. Industrial Exhaust Systems.................................................................................... 53. Industrial Drying Systems...................................................................................... 681 691 701 711> SECTION XII. GENERAL Chapter 54. Owning and Operating Costs............................... 55. Corrosion and Water-Formed Deposits, Causes and Prevention.................... 56. Water Services........................ 57. Codes and Standards................................................................................................ 727 733 747 763 CATALOG DATA SECTION *i Index to Advertisers..................................................................................................................... 3 Index to Modern Equipment.......................................................................................................... #7 Manufacturers' Catalog Data......................................................................... ........'................... *25 vfii INDEX HEATING VENTILATING AIR CONDITIONING GUIDE 1959 Technical Data Section Chapters 1-57 and Pages 1-768 A Air (continued) cleaning, 323, 664 Abatement cleaning devices, 323, 329, 332 air pollution, 73, 75 charged media, 326 smoke, 5, 75 classification of, 323 Abbreviations, 7, 33, 45, 205, 724 electrostatic, 332 installation, 328 Absolute maintenance, 327 humidity, 3 performance, 326 pressure, 4 safety requirements, 328 temperature, 5, 16 - selection, 327, 329 zero, 1, 5 testing, 326 vapor adsorption, 328 Absorbent, 1, 552, 601 combustion, 479 equipment, 552, 553, 602, 603 contaminants, 62, 73, 76, 323, 636 process, 602 . ... radioactive, 81 . temperature, pressure, concentration, cooled condensers, 556 602 coolers, 223, 228, 557 cooling, tropics, 85 Absorbers, 333 dehumidification, 601 ' duct, sound, 344 density, 1 outlet, 346 disinfection, 83, 84 package units, 346 distribution, 237, 267, 654, 664 plate cells, 346 application of methods, 279, 664 plenum, 346 balancing the system, 277 Absorption systems, 552, 553, 601 ceiling outlets, 275 Acceleration, 1 definitions, 267 Acclimatisation, 64 design methods, 292 Acoustics, 335 - directional control, 278 Activated alumina, 603 duct' approaches to outlets, 277 Activated carbon, 91, 604 entering temperature, 202 Activated bauxite, 603 entrainment ratios, 273 Adiabatic, 1 flow patterns, 273, 278 mixing, forced warm air systems, 237 two air streams, 30 friction chart, 284, 285 saturation, 14, 31 furnace systems, 237 system, 14 - high velocity, 263 jet pattern, 273 Adsorbents, 1, 601-603 long slot, discharge from, 272 equipment, 603 noise level, 274 process, 602, 603 outlet location, 237, 238, 276, 277, 279 temperature,' pressure, concentration, outlet performance, 272, 273 604 outlets, 275 ` . Adsorbers, 333 perforated panels, 272 Adsorption, odor, vapor, 76, 328 principles, 268 Aerosol, 1, 73, 84 . radial jete, 271 railway car, 664 recommended velocity, 237, 293 change measurement, 633 return and exhaust intakes, 279 change method, 142, 162 return grille, 237, 279, 654 chemical vitiation of, 61, 76 room air motion, 268, 274 circulation, 61, 88, 237, 664 selection, 276 circulation in drying, 722 smudging, 275 classification of impurities, 73, 323 spreadTlfeT, 268 dust, 73, 323 standards lor, 267 lint, 73, 323 throw, 271, 273 cleaner, 1, 73, 323, 664 vanes, 273 viscous impingement type, 324 velocity, 269, 292, 293 ix Air (continued) - velocity across jets, 269-271 velocity profiles, 271 vertical drop, 274 volume control, 277, 278 wall outlets, 237, 275 - duct (see also Duct) construction, 238, 295, 708-711 design, 238, 239, 283, 292, 295, 707 friction loss, 283 dust concentrations, 75, 79, 80 excess, 470, 478, 479, 495 filter, 323, 324, 331 flow measurement, 40, 630 Sow resistance of coils, 318, 319 impurities, 62, 73, 323 infiltration, 139 causes of, 139 due to wind pressure, 139 through walls, 139 industrial contaminants, 76 leakage, 140, 141 moist, 13 motion, 66 movement, influence of, 64 movement, measurement of, 632 outdoor, 61, 62, 176, 196, 663, 664 permanent impurities, 73 physical impurities in, 62, 73, 75, 76, 88, 323 pollution, 73, 75 abatement, 75 primary, 470, 478 ' quantity required, 61, 199, 479 refrigeration cycle, 550 requirements, 61, 478, 479 room motion, 268, 274 . saturated, 1, 14 secondary, 470, 478, 495 space conductance, 96, 98 standard, 1 sterilisation of, 83, 84, 88 supply and return openings, 237, 275, 279 y supply opening noise, 274, 343 temperature requirements, 66, 70, 157, 168, 668, 681-687 thermodynamics of, 13 unit cleaning devices, 323, 329 washers, 1, 592 water vapor properties, 127 Air change method computing infiltration, 140, 161, 162 Air- conditioning, 1 aircraft, 666 atomic shelters, 83 automobiles in summer, 666 ' Heating Air conditioning (continued) bus, 665 central system, 259, 651 cold therapy, 89 comfort, 2 design requirements, 168 ferer producing, 89 heat sources, 197 " > ' hospitals, 83-02 . humidity, table, 681-687 operating rooms, 86, 87 owning and operating cost, 654, 727 passenger bus, 665 prevention of disease, 83 process and product, 681 atmospheric conditions required, 681 687 calculations, 690 general requirements, 681 problem clasificaticui, 681 typical applications, 681-687 processes, 28 adiabatic miring 30 adiabatic saturation, 31 cooling, 29 . heating, 29 . railway passenger ear, 663 residential, 651 ship, 668 . summer design conditions, 167, 168, 170-175 summer systems, 167, 223, 259, 651 temperature table, 168, 170, 681-687 transportation, 663 . treatment of disease, 83 unit, 223 year-round system, 259, 661 air flow in, 261, 654 control methods, 609, 654 equipment arrangement, 266, 652 location of apparatus, 266, 653 selection, 265, 651 Air cooler, 223 units, 223, 228 defrosting, 229 dfrgign, 229 ' operation, 230 ratings, 229 types of, 229 Air filters, 323 ' Air pollution, 75 control, 75, 332 Air requirements, 61, 470, 664 Air opening noises, 274, 343 Air velocity, 237, 267, 293, 701, 704 cooling towers, 582 design, 293 Air washer, 1, 592 Airborne matter, 74, 75, 323 Airborne infection, 81, 83 control, 81, 83 Aircraft air conditioning, 666 . . Allergic disorders, 90 apparatus, 90 asthma symptoms, 90 hay fever symptoms, 90 limitations of air-conditioning meth ods, 90 Altitude, pressure and temperature, 33 Ariembmeter, 1, 631, 632 deflecting vane, 631 propeller, 631 revolving vane, 631 thermal, 631 Anesthetics, 86 Anthracite coal, 467, 469 firing methods, 469 Ventilating Air Conditioning Guide 1959 Apparatus dew point, 167,199 Aspect ratio, 1, 267 Asthma symptoms, 90 Atmosphere, standard, 1, 33 Atmospherie conditions for industrial processes, 681 687 ' . . cooling towers, 581 make-up water, 588 winter freezing, 589 impurities, 73 " pollen, 81 pressure, 1 Atomic shelters, 83 Atomizing humidifiers, 591 Atomizing oil burner, 488, 491 Attenuation, 336, 344 ducts, 344 duct branches, 344 elbows, 345 grilles, 346 ' Attic, attics fans, 311 location, 311 types, 311 temperature, 158 ventilated, 121 Automobile air conditioning, 666 Awnings, 195 Axial flow fans, 303, 306 B Bacteria, airborne, 81 Baffle, 1, 494 Bare pipe heat loss, 455-457 Barometer, 629 ' . ' Basement coefficients of transmission, 122 heat loss, 160, 161 temperatures, 160 Basementless houses, 160, 240 Bernoulli equation, 35, 2$ Biochemical reactions control of rate of, 689 Bituminous coal, 467, 4 . firing methods, 469 Blast neater, 1 Blow, 1, 219 - Body adaptation to hot conditions, 64 heat loss, 62, 63 odor, 61 thermal interchanges, 62, 63 Boiler, boilers, 501 care, 509 - cast-iron, 501, 506 cleaning, 508 combustion rates, 507 - connections, 374, 507 Hartford return, 374 return, 374 sizing, 375 steam, 374 - construction, 501 design, 502 direct heater, 501 efficiency, 504 erection, 508 fittings, 507 gas-fired, 493, 501, 507 gas-fired units, 493 conversions, 494 grate area, 507 heating, 501 heating surface, 1, 502 X Boiler, boilers (continued) heat transfer rates, 502 horsepower, 1 hot water, SOI, 502 hot water supply, 501, 755 indirect fired, 502 load, 505 magazine feed, 501 . maintenance, 508 oil-fired unite, 489 operation, 508 output, 505 rating, 505, 506 . rating codes, 502 safety, 508 sectional, 501 selection of, 506 based on heating surface and grate area, 507 cast-iron, 506 estimated design load, 506 estimated maximum load, 506 gas-fired, 607 hot water supply load, 506, 753 piping tax, 506 '' radiation load, 506 steel, 501, 502, S06 ' warming up allowance, 506, 507 soot, 483 - space limitations, 507 steam, 501 steel, 501, 502, 506 testing codes, 502, 763 ' troubles, 508 types, 501 . water treatment, 509 working pressure, 501 Bonnet furnace, 510 - Boyle's Law, 15 British thermal unit (Btu), 1 Bucket trap, 377, 378 Building, buildings condensation, 132-138 heat transfer through surfaces, 97 infiltration, 139, 161, 196 intermittently heated, 163 materials, heat transfer through, 97-118, 161 multistory, air leakage, 143 Burner, burners (see also Oil burners) Bunsen, 476 gas, 494 oil, 487, 490 . Bus air conditioning, 665 - Bypass, 373 factor, 202 C Calcium chloride, 601 - Calculated heat loss method, 528 Calorie, 1 Calorific value, 473, 475, 478 Carbon activated, 91, 601, 664 dioxide, 61, 77, 470, 474, 476, 477, 479 481 monoxide, 61, 77, 470, 479-481 Cast-iron boilers, 561 Ceiling _ cooling units, 229 height, 158 . outlets, 272, 275, 664 perforated, 272, 276, 664 unit heater, 218 Centra! air-conditioning systems, 259 accessibility, 266 air quantity, 261 Index to Technical Data Section Central air-conditioning systems (con tinued) all air, 263 ' apparatus dew point, 167,199 control, 259. 619 load, 167, 261 corrosion, 733 gn procedure, 259 - duaT duct, 263 effectual temperature difference, 261 equipment arrangement, 259. equipment selection, 265 evaporative cooling, 264 fan and coil unite, 264 fan system, 1, 259 features, 259 ' beating load, 151, 281 high velocity, 263, 275, 295 humidity control, 260 individual room control, 260 induction units, 262 high pressure type, 262 low pressure type, 262 location of apparatus, 266, 653 outdoor air, 259 precooling, 265 reheating, 260 selection, 265 sensible cooling, 265 summer only, 651 temperature differential, 261 unitary central types, 262 year-round, 259 zoning, 260 . Centrifugal compressors, 555 . condensing unit, 555 VLW Chart air elimination, 362 air flow, unequal openings, 144 air friction, 284, 285 airborne particulate matter, 74 air moisture content, 606 . ' air washer conditions, 596 axial jet velocities, 270 chimney capacity, 517-520, 523 chimney draft, 516-520 ' chimney flow, 517-520, 523 color, 12 * comfort, 70 compressor and coil performance, 561 correction for pipe roughness, 286, 287 dehumidifier performance, 602, 605, 606 dew-point conversion, 608 disease frequency,-84, 85 draft required, 516 * drying time, 716 dust particle size, 74 economical thickness pipe insulation, 461 .; . edge loss, 424 effective diameter, 269 effective temperature, 69 elbow loss, 290, 363, 397 entrainment ratio,' 272 estimating surface temperature, 423, evaporation rate, 718 expansion factor, 42 fan characteristics, 306-307 fan sound level, 306, 307, 342, 343 fan system characteristics, 307 filter resistance, 326 firebox dimensions, 487 flow coeffidente. 41, 42 flow due to wind, 144 flow through opening, 144, 145 Chart (continued) flue area, 147 flue loss, 476, 477 ` friction air ducts, 284, 285 friction factor, 37 - friction in pipes. 364, 369, 370, 393, 394, 396, 415, 749-751 fuel consumption, 498 fuel oil index, 474 gas rents, 527 head due to temperature, 392 heat flow, glass, 185 beat emission by radiation from panels, 421 beat endurance, 65 heat loss - body, 62, 63, 66, 67 canvas surface, 460 coeffidente, insulated ducts, 301 convection from panel, 422 duct. 301 insulated pipe, 458-460 insulation, 458-460 heat pump performance characteristics, 570 system balance, 570 ' temperature levels, 569 beat stress index, 693 humidity, 720 infiltration, 140 inside surface temperature, 423, 424 insulation of cold pipe, 464 . Langelier formula, 737 ' moisture loss from body, 67 * motor characteristics, 641, 643, 645-647 MRT elevation, 65 - orifice coefficient, 40 .. orifice installation, 43 - - panel heat output, 421-424 permisible relative humidities for vari ous transmission coeffidente, 133 pipe color classification, 12 pressure loss in ducts, 284, 285 pressure loss in elbows, 290 pressure loss in faucet^ 750 pressure loss in meters, 750 * psychrometric charts, 17,28, 68, 720 persons at rest, 68 pump performance, 398 radial jet velodties, 270 radiation between black bodies, 56 radiation shape factor, 55 refrigerant pressure-enthalpy, 542 refrigeration horsepower, 731 solubility of calcium rails, 736 solubility of gases, 735 sound attenuation, 345, 348 sound pressure level, 338, 340, 350 static deflection, 353 static regain, 296, 297 system characteristics, 307 thiclmpsa pipe insulation to prevent sweating, 464 . velocity ana velocity head, 290 vena contracts location, 44 viscosity, air, 36 * viscosity, water, 36 well water temperatures, 596 Chemical, chemicals laboratory hoods, 705 reactions, 689 control of rate of, 689 vitiation of air, 61, 76 water treating, 739, 740, 741, 744 Chimney, chimneys, 515 available draft, 515, 516, 519 C -boiler connections. 507 construction details, 524 determining sizes, 518, 521 ' xi Chimney, chimneys (continued) effect, 1 ! efficiency, 520 factors affecting draft, 515, 521 fireplace, 526 gas heating, 523 general considerations for, 522, 525 incinerator, 524 industrial, 516-518 . performance, 515-517 - residential, 518, 519 short, 520 sizes, 517, 518, 521 ` static draft, 515 theoretical draft, 515 Cinders, 75 ' Circular equivalents of rectangular ducts, 287-289 Cleaning boilers, 508 Climatic conditions; 151, 168 * Closed expansion tank, 403-406 sizing formula, 404 Coal, coals " ' - anthracite, 467-469 bituminous, 467-470 classification of, 467 combustion of, 469. draft required, 471, 516 estimating consumption, 527, 536, 537 firing methods, 469-471 lignite, 469 . Codes (see alan Standards), 763 installation, 763 National Building, 524 rating, 763 space heaters, 512 testing, 763 Coefficient of performance, 1, 541, 569 cooling, 1, 570 . heating, 1, 570 Coefficients of transmission, 3, 93, 102 122, 124 . basement, 122, 159 - floor, 122, 160 wall, 122, 159 ceiling and roof, 110, 112-122 coils, 209, 320 correction for insulation. 111 correction for framing, 121 doors, 123, 124 floors and ceilings, 110, 112-118, 121 frame construction, 102, 108, 110 glass, 123 . glass block walls, 123 insulating materials, 99-101 masonry partitions, 109 . masonry walls, 104-107 overall, 93, 320 -- formulas for calculating, 93, 97 practical; 97 - roofs, 114-118, 121 . skylights, 123 ' windows, 123 ^ wind velocity correction, 124 Coil, coils, 313 air flow resistance, 319 applications, 317 arrangement, 313; 315 bypass factor, 202 construction, 313 cooling, 314, 319 dehumidifying, 319, 321 determining refrigeration load, 322 * direct expansion, 315 dry cooling, 320 film coefficient, 320 . Heating Ventilating Air Conditioning Guide 1959 Coil, coils (continued) Sow arrangement, 315 - heat emission, 209, 320 heat transfer surface, 319. 320 heating, 318 performance, 320, 321 cooling, 320 dehumidification, 321 heating, 320 pipe, 209 rating, 318, 319 selection, 318 cooling, 319 dehumidifying, 319 _ heating, 318 steam, 314 uses, 313 water, 314 Coke classification of, 469 estimating consumption, 537 firing methods, 470 Cold process exhaust, 702 Cold therapy, 89 Color, piping systems, 12 . Combustion, 467 adjustments, 488, 490, 495 air inlet, 476, 483 air required, 479 analysis, 479 chamber, 487, 490 complete, 477 dew point, 483 efficiency, 479, 490 Sue gas, 479, 480 gas, 476 . heat balance, 481 heat of. 478 incomplete, 478 index, 473 losses, 481 oil, 473 perfect, 477 process, 486, 489, 495 principles of, 476 rates, 494, 498, 516 smokeless, 470 stoker, 486 Comfort air conditioning, 2 air-conditioning systems, 259,651,663 chart, 70 design conditions, 167, 168 line, 2 summer, 66-70 sone, 66, 70 Compartment dryer, 722 Compressor,. compressors, 554 centrifugal, 555 reciprocating, 554 refrigeration, performance of, 560, 561 Condensate, 2, 388, 741 Condensate return pumps, 375 Condensation, 2, 127 buildings. 132, 134 concealed, 134 control, 134 . cooled structures, 137 flue gas, 483 surface, 132 visible, 132 Condensers, 556, 589 'air cooled, 556 design data, 585 evaporative, 589 Condensers (continued) water cooled, 556 Condition line, 32, 199 Conductance, 2, 93, 94 air space, 98, 99 building materials, 99-101 film, 93 insulators, 99-101, 454 soil, 94, 95 surface, 2, 95, 96, 98 Conduction, 2, 47 drying methods, 722 electric heaters, 231 equation, 47 steady-state solutions, 54 Conductivity, 2, 47, 93, 94, 99-101 batt type insulation, 99 building boards, 99 building materials, 99-101 homogeneous materials, 94 insulating materials, 99-101, 454 insulation blankets, 99 loose-fill insulation, 100 masonry materials, 100, 101 plastering materials, 101 rigid insulation, 100 roofing construction, 100, 101 siding materials, 101 soil, 94, 95 woods, 101 Conductor, 2 Conduits for piping, 385, 386 Connections boiler, 374, 406, 412, 507 heating units, 380 Control, controls airborne infection, 83 aircraft temperature, 666, 667 automatic, 609 automobile temperature, 666 biochemical reactions, 689 central fan systems, 259, 619 chemical reactions, 689 contaminant by exhaust, 699, 701 corrosion, 733 crystallization, 689 dew-point, 689 . high temperature water system, 416 high velocity systems, 297 laboratory conditions, 690 motor, 639 panel heating, 432 passenger bus temperature, 665 passenger car, railway temperature, 664 humidity, 664 . pneumatic systems, 609 refrigeration, 554, 556, 557 service water temperature, 759 ship air conditioning, 669 slime, 739 sound, 335 static electricity, 689 temperature for machining, 689 ventilation, 146 vibration, 352 Control, automatic, 609 action types, 610 air flow, 617 air washers, 621 applications, 618 auxiliary equipment, 613 central fan systems, 619 components of systems, 610 xii Control automatic (continued) controlled devices, 612 controllers, 610 cooling, 620 dehumidification, 620 design coordination, 614 electric, 609, 611 electronic, 609, 611 equipment selection, 614 floating, 610 flow, 616 fuel-burning equipment, 498 fundamentals, 609 gas burners, 499 heating coil, 619, 620 high velocity systems, 297 hot water heating, 623 humidity, 621 hydraulic, 609 indicating, 612 individual room, 618 measuring elements, 611 oil burners, 499 operating, 609 outdoor air damper, 619 panel heating, 432 pneumatic, 609, 611 preheater coil, 619 primary, 499 proportional, 610 recording, 612 residential, 626 size of area, 614 space conditions, 614 static pressure, 622 steam flow, 616 steam heating, 624 stokers, 499 system types, 609 terminal equipment, 625 typical system, 622 unit heaters, 220 unit ventilators, 215 valves, 612 water flow, 617 sone, 618 zone systems, 624 Controllers, 609, 610 functions, 610 types, 612 ' Convection, 2, 47, 51 equation, 48 ' film coefficient, 48 free, 48-50 unit conductances, 49, 50 Convector, convectors, 2, 207, 209-211 correction factor, 210, 211 induction, 262, 263 ratings, 210 ' Conversion burners, 494 equations, 8, 9 Coolers, 223, 228, 557 Cooling, 167 air-conditioning units, 223,652 air washer, 579 atmospheric water, 579 coil selection, 318, 319 comfort, 167 ,, evaporative, 264, 591 industrial, 167, 681 load, 167, 261 - calculations, 167, 202 total, 167 methods, 652 performance of coils, 320, 321 ponds, 580 Index to Technical Data Section Cooling (continued) residential, 651 SScS~W,680make-up water, 588 sire of equipment, 588 winter freezing, 5o9 systems, 259, 591, 651, 663 towers, 581 atmospheric, 581 design, 582-585 location, 588 maintenance, 588 mechanical, 581 operation, 588 performance, 582-585 piping, 753 selection, 587 tropical conditions, 85 units, 223 component parts, 223 control, 227, 230 definitions, 223 defrosting, 229 design, 223 performance, 223, 228 ratings, 227, 229 remote, 224, 225 sound isolation, 228 types of, 229 water, 579, 585 ` water piping, 753 Copper elbow equivalents, 396 Corrosion, 733 air ducts, 743 atmospheric, 735, 743 boilers, 739 cathodic protection, 744 coal storage equipment, 743 cold water, 733 condensates, 735, 741 flue gas, 483 flues, 743 heating systems, 739 hot water, 739 industrial exhaust systems, 712, 713 minimizing condensate, 741 pipe, 740, 743 prevention, 712, 735 refrigerating systems, 741 underwater, 740 " Cost of air conditioning, 654, 727 amortisation, 727 condenser water, 731 first, 727 fixed charges, 727 heating, 731 interest, 728 installed, 728 insurance, 729 f labor, 730 maintenance, 729 owning and operating, 727, 730 rent, 729 service, 729 taxes, 728 refrigeration equipment, 730 water, 730 Crack length method, 140 used for computations, 162 Crystallization control rate of, 689 Cylinder dryer, 722 ' D Dalton's rule, 15 Damper, dampers, 239, 259, 267, 277, 278, 307, 471, 613, 619 Darcy formula, 36 Decibel, 2, 335 Declination of sun, 2 Definitions, 1-6 Defrosting, 229 Degree day, 2 for cities, 529, 538 formula for, method, 535 industrial, 538, 539 operating unit, 539 unit fuel consumption, 535, 536 Degree of saturation, 5, 14, 17 Dehunudification, 2, 594, 601 air-conditioning units, 225 air washers, 594 - coil selection, 313, 319 comparison of methods, 601 control, 620, 621 definitions and methods, 601 elevated pressure, 606 equipment, 594, 601, 603 performance, 602, 605, 606 estimating loads, 607 liquid methods, 601, 602 moisture load, 607 ships, 669 solid methods, 602, 603 vapor transfer, 607 Dehumidifying agents, 601 absorbents, 601 adsorbents, 601 'Dehydration, 2 Density of air, 1 Design conditions summer, 168, 170-175 winter, 152-157 Desiccants solid, 602 Dew point apparatus temperature, 167, 199 flue gas, 483, 743 temperature, 5, 15 Dichlorodifluoromethane, 542-544, 560 Diffusivity, thermal, 2. 559, ' Direct ' expansion coils, 315 fired unit heater, 213 indirect heating unit, 2 radiator, 5 return system, 2, 397 Distribution of air (see Air distribution), 237, 267, 664, 667 District heating, 383 condensate return, 388 meters, 389 pipe insulation, 388 piping. 385, 387, 388 conduits for, 385 inside, 388 sizes, 385 tunnels, 387 - steam requirement, 383 Domestic oil burners, 487 - Door, doors .coefficients of transmission, 124 leakage, 140, 141 natural ventilation, 145 Down-feed one-pipe riser, 2, 4, 356 - jdii Down-feed (continued) steam beating, 2, 35S Draft, drafts, 2, 515 available, 515, 516, 519 calculations, 515 chimney, 515 control, 471 factors, 515 forced, 515 general equation, 515 head, 2 industrial chimneys, 516 natural, 142, 515 regulation, 471 regulator, 489 residential chimneys, 519 requirements, 471, 516, 522 appliances, 522 theoretical, 515 Drawing symbols, 9-12 Drip, drips, 2, 358, 379 Drum dryer, 722 - Dry air, 1 composition, 13, 478 filters, 325 properties of, 16 velocity, head, 290 Dry-bulb temperature, 5 Dry cooling coils, 313, 320 Dry return, 5, 355 Dryer, dryers, 721 cabinet, 722 calculations, 721 compartment, 722 cylinder, 722 drum, 722 rotary, 722 spray, 723 tunnel, 722 Drying, 2, 689, 715 agricultural, 723 application of hygrometry, 719 calculations, 721 chart, 716, 718 conduction, 722 constant rate period, 716, 717 convection, 722 critical moisture, 715 effect of air velocity, 717 equations, 717 equilibrium moisture, 715 equipment, 721 example, 723 external conditions, 716 factors influencing, 715 falling rate period, 718 internal conditions, 716 mechanism of, 715 methods, 721 conduction, 722 convection, 722 radiant, 721 periods, 716 problem, 723 radiant, 721 systems, 715 terminology, 715 tobacco, 723 - . y Duet, ducts, 239, 283 air velocities in, 292, 293, 296, 297, 704. 711 approaches to outlets, 277 area change, 291 attenuation, 344 circular equivalents, 287-289 Heating Duet, ducts (continued) construction details, 239, 298, 708-711 design, 240. 292, 707 design methods, 292 equal friction, 293 static regain, 294 - velocity reduction, 293 dual duct, 263 dynamic losses, 287 elbow friction losses, 289 exhaust design 707 friction losses, 285 heat loss coefficients, SIO, 301 lining, 345, 346 measurement of velocities, 632 perimeter, 240 pressure changes, 283 pressure loss, 283, 285 rectangular equivalents of round, 287 289 resistance, 255 roughness correction, 286 sizing, 2S4, 285, 292 sound absorbers, 344-347 symbols for drawing, 10-12 system design, 237, 2S3, 295, 707 velocities, 293, 295 warm air perimeter, 240 weight, 299, 300 Duct sizing, 284, 285, 292-297, 707 equal friction method, 293 general rules, 707 static regain method, 294 velocity method, 293 . Dost, 2, 62, 73 combustible, 80 concentrations, 79 control, 84 counter, 74 determination, 73 filters, 324, 329, 331 industrial, 76 particle size chart, 74 preripitatora, 325, 332 removal, 323 size, 74 Dost collectors, 323, 329 application, 323, 327, 329 centrifugal, 329, 330 cyclone, 330 cloth, 331 degree of dust removal, 329 electrostatic, 332 fabric, 331, 332 factors affecting selection, 329 inertial separators, 329, 330 settling chambers, 330 scrubbers, 330, 331 fewfing inethQrtiy 39ft types, 329 wet, 330 centrifugal, 331 packed tower, 331 spray towers, 331 washers, 331 wet filters, 331 Dynamic head, 3, 287 losses, 287 E EDR (Equivalent Direct Radiation), 4. .356 defined, 4, 207 Effective temperature, 5, 66 chart, 67, 68-70 ' index, 66 Ventilating Air Conditioning Guide 1959 Efficiency boiler, 504 conversion burner furnace, 511 utilization, 527 Ejector nozzles, 275 Elbow attenuation, 345 copper equivalents, 396 friction losses, 289, 290, 396 iron equivalents, 396, 416, 752 sheet metal, equivalent, 290 Electric, electrical baseboard, 232 convector, 232 demand control, 235 heat applications, 231 heating, 231 calculating capacities, 234 central, 234 control, 235 domestic water, 756 equipment, 232 heat pump, 234, 563 operating costs, 235 power considerations, 235 resistors, 5, 231 systems, 232 Units, 232-234 hot water heating, 756 installation methods, 232 motor design limits, 640 panel heating, 233, 234, 432 precipitators, 332, 335 radiant convector, 233 radiant beating, 233, 432 resistors, 231, 233 steam radiator, 233 systems, 232, 609, 639 voltage ratings, 640 Electricity, static, 87, 689 Emissivity, 52 Enclosed radiator, 271 Energy, Conservation Law, 13 Enthalpy, 2, 13, 16, 17.27 free, 2 \ specific, 2, 16 Entropy, 2, 16, 17 mixing, 17 specific, 2 Equivalent evaporation, 2 Estimating fuel consumption, 527 Eup&theoscope, 634 Evaporative apparatus for heat rejection, 579 condensers, 589 cooled, unit conditioners, 223 cooling, Ml, 597 Evaporators, 557 Excess air, 470, 477, 479, 490, 495 Exhaust opening, 279, 701 measurement of velocities, 632 Exhaust systems, 701 air flow equipment, 711 axial velocity formula, 702 capture velocities, 701 construction, 708,' 709, 711 conveying velocity, 704-706, 711 corrosion, 712, 713 duct construction, 708-711 duct design, 707-711 duct resistance, 708 duct system design, 707 duct velocity, 704-706 ducts for, 707 ' air velocities in, 704-706 construction, 708 xiv Exhaust systems (continued) design, 707 . resistance, 708 dust filters, 711( elements, 701 * equipment, 701, 711 exhaust requirements, 709, 710 general requirements, 701 hoods, 701 air flow, 702 ' air velocity, 702 axial velocity formula for, 702 canopy, 704-706 capture velocities, 701 chemical laboratories, 705 design principles, 701 hot processes, 703 induced air flow, 707 _ kitchen, 705 ' special exhaust requirements, 703 spray booths, 706 suction, 712 velocity contours, 702 .- ventilation rates, 704-710 make-up air, 711 maintenance, 712 materials, 709, 711-713 performance, 712 pressure loss, 708 specifications, 708 suction requirements, 712 types of fans, 711 velocity contours, 702 velocity requirements, 704-710 ventilation rates, 704-710 Expansion factor, gases, 42 of pipe, 380 tank installation, 403 tank piping, 403 tank site, 404 tanks, 403 valves, 557 . - Explosion hazard, 86 - Extended plenum systems, 244-247, 250 F Fan, fans, 303 applications, 310 arrangement of drives, 308 attic, 311 location, 311 axial flow, 303 central system, 1, 310 centrifugal, 303, 305 characteristic curves, 305-307 control, 307 designations, 304 ' drive position, 309 efficiency, 305 exhaust, 310 furnace system, 2, 327 hot gas, 311 installation, 310 kitchen, 311 laws, 301 marine, 310 mine, 310 motive power, 308 - noise generated, 339 oil burner, 488- performance, 303, 305-307, 342 propeller, 303 radial flow, 303, 306 rotation, 308 selection of, 309 air-conditioning systems, 310 industrial exhaust systems, 711 special application, 311 ' Index to Technical Data Section Fan, fans (continued) speed, 309, 310 ____ system characteristics, 306 types, 303 unitary systems, 310 velocity, operating, 309 volume control, 307 Fanning formula, 36, 393 Fever therapy, 89 . equipment for production of, 89 Fick's Law, 128 Film conductance, 48, 93, 96, 98 Filter, filters, 323 air-conditioning units, 224 atmosphere, 323 charged media, 326 dry air, 325, 331 dust, 323 furnace, 509 installation, 328 ionizing, 325 maintenance, 327 moving curtain, 324 performance, 326 selection, 327, 329 testing, 326 vapor adsorption, 328 viscous impingement type, 324 ' Fitting, fittings allowance pipe, 363, 396, 416, 752, 753 sheet metal, 248, 249, 290 ` Flash leg, 380 Flexible mountings, 352 - Float trap, 376, 377 Floor cooling unit, 224 heat transfer coefficients, 110, 112, 113, 119 . panel design, 429-432 unit heater, 218 Floor slab heat loss, 122, 160 Flow coefficient, orifices, 40 compressible fluids, 38 critical, 40 fluids, 35, 38 through nozzle or orifice, 39 measurement - head meters, 40, 43 liquids, 40 . orifices, 40 Pitot tube, 44,. 630 variable area meters, 44 Flow meters, 40, 389, 631 Flue gas analysis, 479 Flue gas dew point, 483 Flue gas loss, 481 Fluids, flow, 35, 38 theory, 35 Fluid meters, 40 Fog, 2, 73, 76 f Force, 3 Forced air heating system, 237 ceiling panel systems, 254 design, 240 . large systems, 250 perimeter systems, 240-247 summer operation, 258 circulation pipe sixe9, 393 convection, 48-50 Fourier's Equation, 129 Free convection, 48-50 enthalpy, 2 - Freezing in nipes, 463 * Friction loss air ducts, 257, 284, 285 circular pipes, 36 effect of area change, 291 elbows, 248, 249, 290, 363, 396, 416, 752, 753 gas piping, 496, 497 high temperature, 415, 416 noncircular pipes, 38 ' refrigerant piping, 558, 559 water heating, 393-396, 415 < water piping, 393-396, 415, 749-753 Fuel, fuels, 467 analysis, 467, 472, 475 burning equipment, 485 burning rates, 498 calorific value, 478 classification, 467, 468, 471, 474 consumption, 527 calculated heat-loss method, 528 degree-day method, 535 load factor, 539 maximum demands, 539 uni^ 535-537 utilization efficiency, 527 firing methods, 40-471 gas, 474 heat of combustion, 478 heating value, 478 . liquid, 471 solid, 467 unit consumption, 535, 536 utilization, 510 Fad oil, 471 blended, 471 calorific value, 473 carbon residue, 472 catalytically cracked, 471 classification of, 471, 472 combustion of, 473, 489 estimating consumption, 498, 535-537 flashpoint, 472 grade of, 471 maximum carbon dioxide values, 479 piping, 493 ' preheating, 491 residual, 472, 473 storage, 493 straight-run, 471 'theoretical air requirements, 479 thermally cracked, 471 viscosity, 472 weight per gallon, 473 Fumes, 3, 73 ' Furnace, furnaces, 3, 509 capacity, 510 casings, 612 cast iron, 510 design, 509, 511 efficiency, 511 duct, 495 fan, 509, 510 filtera. 509 forced warm air, 509 gas-fired units, 493 grate area, 511 gravity warm air, 509, 510 heating surface, 610 heavy duty, 510 humidification equipment, 512 materials, 510 mechanical warm air, 509 controls, 253 cooling methods, 258, 651 ' dampers, 239 - ducts, 239- fans, 509 , filters, 509 xv Furnace, furnaces (continued) method of designing, 511 motors, 509 ratings, 511 oil-fired units, 510 prime beating surface, 510 rating, 510, 511 steel, 510 types, 509 volume, 3, 471, 487, 490 warm air, 509 * G Gage, gages draft, 630 pressure, 4, 629 sheet metal, 298, 299, 709 Garage ventilation, 148 Gas, gazes, 73, 77 appliance rating, 496 atmospheric, 73, 80 burner controls, 500 burners, 494 calorific value, 474, 475 central heating, 493 chimneys for heating, 523 classification of, 474 combustion of, 476 equipment, commercial, 497 equipment, industrial, 497 equipment ratings, 496 estimating consumption, 536 expansion factor, 42 flammable, 78 flue, 479 analysis, 480 dew point, 483, 743 loss, 480, 481 heaters, 514 liquified petroleum, 475 manufactured, 475 mixed, 475 natural, 474-476 perfect relationship, 15 pipe size, 496 solubility, 736 space beaters, 495, 514 wall heaters, 495 Gaseous fuels, 474 calorific value, 474, 475 classification of, 474, 475 combustion of, 476, 495 maximum carbon dioxide values, 480 products of combustion, 477, 479 properties of, 475 specific gravity, 475 theoretical air requirements, 479, 480 typical analyses, 475 Gas-fired appliances, 493 adjustment, 495 boilers, 493 combustion process, 495 controls, 498, 500 conversion burners, 494 furnaces, 493 pipe size, 496, 497 ratings for, 496 sizing heating plants, 496 space heaters, 495 ' Glass coefficient of transmission, 123 design tables, 186-194 heat absorbent, 189 shading of, 195 - solar heat transmitted, 184 window transmittance, 186 - Heating Class block walls coefficient of transmission, 123 solar heat gain, 191-194 Globe uiefEQOmcicr, 634 Graphical symbols for drawings, 9-12 air conditioning, 9, 11, 12 ductwork, 19-12 heating, 9-11 piping, 9-10 refrigerating, 11, 12 ventilating, 10, 11 Grate area, 3 Creek alphabet, 6 Grille, grilles (see Regiiteri), 237, 267 275, 343 air supply noises, 343 attenuation, 343-344 exhaust, 279 locations, 237, 276, 279 door, 279 floor, 279 wall, 279 mechanical furnace systems, 237 noises, 279, 343 railway car, 664 recirculating, 664 return, 237, 279 velocity, 237, 269, 279 Ground temperatures, 159 ' Guarded hot plate, 634 Gun type oil burners, 488 H Hangers, pipe, 448 Hartford return connection, 356, 374, 375 ' Hay fever symptoms, 90 Hazards high temperature, 64, 86, 691 Health, 83 . Heat, 3 area transmitting surface, 758 auxiliary sources, 163, 197 balance, 481 combustion, 468, 473, 475 cramps, 64 emission of . appliances, 197, 200, 201 occupants, 66, 67, 197 pipe coils, 209, 420 exchange measurements, 62 flow resistance, 51 flow through glaws, 123, 184 flow through roofs, 102-110, 178 flow through walls, 110-118, 178 gain, 167 generated by motors, 197 humid,' 3 ' infiltration equivalent, 196 instantaneous load, 169, 191 introduced by outside air, 196 lag, 191 latent, 3, 162, 167, 196, 198, 204 liquid, 3 loss, pipe, 455 mechanical equivalent of, 4, 8 methods of, transfer, 47 . radiant, 48, 51, 52 - ratio, sensible, 199 removal, natural ventilation, 144 sensible, 3, 161, 198 gain, 167, 196 loss, 161 specific, 3 Ventilating Air Conditioning Heat (continued) stroke, 64 total, 3 Lrauifer, 47, 102-118, 300, 75S boiler rates, 502 convective, 2 overall coefficients, 93, 97, 102-118, 320, 753 surface coils, 320 symbols,?, 50, 93 through building materials, 93 upper limits, 65 water coils, 758 Heat gain appliances, 197, 200, 201 ceilings, 195 components of, 167 ducts, 194, 300 electrical heating equipment, 200 floors, 195 gas burning equipment, 200 glass, 184-189 glass blocks, 188-194 infiltration, 196 instantaneous, 169, 191 latent, 169, 196, 198 lights. 197 ` miscellaneous, 199 moisture, 198 occupants, 197, 198 outside air, 196 partitions, 195 people, 66, 198 roof, 178-184 sensible, 169, 196 shaded windows, 195 solar, 184 steam heated equipment, 201 various sources, 163, 199 ventilation, 196 wall, 178, 182, 183 Heat loss air change, 161 bare pipe, 209, 455 basement, 160 ' building materials, 99-101 ceiling, 110, 112, 113 computations, 151 calculated method, 151 crack method, 162 exposure factors, 163 factors of safety, 163 number of air changes, 162 duct, 300 ' glass, 123 floor slab, 160 infiltration, 161 insulated pipe, 458-463 latent, 162 pipe, 209, 455 residence problems, 163 roofs, 114-118 sensible, 161 surface to air, 98, 99 through ceilings and roofs, 161 transmission, 93, 161 ceilings and roofs, 110, 112-118 walls, 102-109 Heat pomp, 3, 563 application, 574 basic circuits, 565 coefficient of performance, 565 components, 572 cooling load. 575 criteria for feasibility, 574 design, 575 distribution system, 575 xvi Guide 1959 Heat pump (continued) equipment selection, 572-575 heating load, 571 heat silk, 567-569 heat source, 567-569 . heat storage, 575 history, 563 operating cost. 572 performance characteristics, 569 performance factor, 565 seasonal performance, 571 selection, 575 system balance, 570 types, 565, 566 Heat removal, 144 Heat stress index, 1, 692 Heater, heaters blast, 1 direct-fired unit, 217, 218 electric, 217, 220, 232 gas, 514 design, 514 efficiency, 514 materials, 514 oil, 513' . design, 514 ' materials, 513 rating, 513 testing, 513 radiant, 495 solar water, 760 solid fuel, 512 design, 513 material, 512 rating, 512 testing, 512 space, 512 - installation, 514 unit, 217, 232 vertical blow unit, 218 - . Heating air-conditioning units, 223. boilers, 501 - surface, 1, 502 coil selection, 318 comfort, 151 district, 383 effect, radiator, 211 electric, 231 hot water, 756 load, 151, 261, 506 performance of coils, 320, 758 reversed cycle refrigeration,' 563 steam systems, 355 surface, 5 square foot.of, 4 symbols for drawing, 9 vacuum systems, 6, 355, 359 vapor, 6, 358 warm air system, 6, 237 water, 391, 409, 753 Heavy duty fan furnace, 510 High duty humidifiers, 591 . High temperature hazards, 64, 88 High temperature systems, 409 basic system, 409 boilers for, 411 control, 413, 416 design, 409, 414 direct contact heaters, 413 expansion cushion, 411 features, 409 . . fittings, 414 fitting pressure loss, 416 heat exchangers, 413 pipe, 414 pumps, 414 Index to Technical Data Section High temperature systems (continued) storage, 418 - water treatment. 418 High velocity systems, 263, 295 design, 295 control, 296 Hood, hoods, 701 Writ nramss exhaust. 703 Hospital, hospitals air conditioning in, 83, 91 operating rooms, 86 . air conditions, 87 reducing explosion hazard, 86 sterilization of air, 83 ventilation requirements, 87 Hot water boiler supply load, 506, 753 coil surface, 758> demand per fixture, 747, 748, 755 person, 754 . distribution, 390 ' electric heating, 756 beat pump, 762 hearing surface, 758 indirect heater, 757 methods of heating, 755 panel heating, 419, 424 safety devices, 760 service, 753 service piping, 759 solar heaters, 760 storage tank, 753 supply boilers, 501, 755-758 piping, 759 temperature control, 759 Hot water heating systems, 3, 2 circulation head, 391, 392 direct return system, 2 elbow equivalents, 398, 416 expansion tank, 403 forced circulation, 391 friction heads, 393-396 vity, 391 Kh temperature, 409 basic system, 409 boilers, 411 control, 413, 416 direct contact heaters, 413 expansion cushion, 411 features, 409 heat exchangers, 413 pipe fittings, 414 pumps, 414 storage, 418 water treatment, 418 mechanical circulators, 402, 414 one-pipe forced circulation, 398 pipe sizes, 393-396,' 415 - piping design, 393, 414 relief valve, 408 reversed return system, 397 two-pipe, forced, 397 Human body acclimatization, 64 adaptation, 62, 64 cold conditions, 63 hot conditions, 63 heat emission, 66 high temperature hazard", 64 metabolic rates, 62 odors, 62 - temperature, 62 Human body (continued) thermal interchanges, 62 zone of evaporative regulation. 63 Humid heat, 3 Humidification, 3, 224, 591, 594 control, 254, 621 direct, 594 evaporative pans, 512 forced furnace systems, 254 Humidifier, humidifiers air washer, 591 atomising, 591 cleaning, 512 evaporating pans, 512 high duty, 591 self-contained, 591 spray, 591 unit, 591 Humidistat, 3, 612 Humidity, 3 absolute, 3 control, 260, 621, 681, 687 influence of, 66, 88 measurement of, 633 nurseries for premature infants, 88 ratio, 3, 14 relative, 3, 14 specific, 3 Hygrometers, 633 Hygroscopic materials, 687 Hygrostat, 3 I Impulse trap, 378 -Inch of water, 3 Indoor temperature, 157, 167, 168 Induction units, 262, 262 high pressure types, 262 low pressure types, 262 Industrial air conditioning, 681 chimneyB, 516 degree dayB, 538, 539 exhaust systems, 701 Infiltration causes, 139 due to wind pressure, 139 heat losses, 161 latent. 162 sensible, 161 measurement, 633 prevention by waling, 143 temperature differences, 142 through outside doors, 140, 141 through walls, 139 through windows, 140 Inflammability, 80. Instruments, 627 Insulated constructions. 111, 113, 119 121 Insulating materials. 108, 454 calculating coefficients, 111, 113 conductivities and conductances, 99 101 Insulation, 3, 453 economical pipe thickness, 459, 461 edge, 160 - low temperature pipe, 463 pipe, 453 pipes to prevent freezing, 463 reflective, 98, 100 sound, 344-347 thermal conductivity, 454 underground pipe, 388 xvH Ionization, 62 Intermittently heated buildings, 163 Tsobaric 3 Isothermal, 3 J Jets, 268 expansion, 269 radial, 271 velocity, 269 Joints, duct, 298, 299 K Kata thermometer, 632 Kitchen hood, 705 L Laboratories, 690 ( Latent heat, 3, 162, 167 loss, 162 Laws of thermodynamics, 6 Leakage of air, 139 (see Infiltration) door, 140-142 window, 140, 141 Light heat gain, 197 Lignite, 469 Liquid absorbents, 601 heat of, 3 Lithium bromide, 552, 553, 601 Lithium chloride, 601 Load cooling, 167, 191, 261 design, 3, 167 factor, 539 heating, 151, 261 lighting, 197 maximum, 3, 506, 539 refrigeration, 167 M] Mach number, 38, 39 Machine vibration, 352 Manometer, 3, 629 Marine (see Skip heating, ventilating, air conditioning) Mass, 4 Mean radiant temperature, 65, 421, 432 Meter, meters, 40, 389, 629 area, 40, 44, 389 condensate, 389 flow, 40, 44, 389 force, 40 head, 40, 43, 389 . installation, 389 orifice, 44, 631 selection, 389 velocity, 3S9 venturi, 631 Metering, liquids, 40, 389 Micromanometers, 629 Micron, 4 Mist, 73 ' Moist air, 13 properties, 13 saturation, 14 specific volume, 18 Moisture, 127, 687, 715 content, 687, 688, 716 in building construction, 127 Heating Moisture {continued) load, 198, 607 loss per person, 67, 198 movement in materials, 128 permeability, IS) regain, 687 transmission 128, 607 Mol, 4 Molecular force of water, 128 Motor, motors, 163, 197, 639 alternating current, 641 capacitor type, 644 classification, 642, 643, 649 control, 646, 648 control equipment for, 646 current limitation, 646, 647 design limits, 640 drives, 639 electric, 639 enclosures, 649 glossary, 648 heat generated by, 163, 197 hermetically enclosed, 645 increment limitation, 646, 647 multispeed, 644 . polyphase, 641 rating, 648 repulsion induction, 645 selection, 639 single phase, 644, 647 speed characteristics, 640 speed classification, 650 speed ranges, 640 split phase, 645 squirrel cage, 641, 646 starting methods, 646 synchronous, 642, 644, 646 wound rotor, 641, 647 Mountings, flexible, 352 N Natural draft, 515 towers, 587 Natural ventilation, 143 general rules. 146 heat removal, 144 Noise, noises, 335, 653 absorptive material, 345 air-conditioning system, 335,653 air supply opening, 343 apparatus for measuring, 336, 638 attenuation, 336 control, 335, 337 controlling vibration, 352 cross transmission between rooms, 352 design room level, 347 . duct sound absorbers, 344-347 duct system attenuation, 344 fans, 339 general problem, 336 grille, 343 intakes, 279 ` kinds of, 339 levels, 274, 339-341 loudness, 336 measurement, 336, 636 plate Cells, 346 plenum absorption, 346 recommended levels, 340, 341 through building construction, 339, 853 transmitted through ducts, 339, 352 unit of measurement, S35, 338 Nozzle flow, 39, 40 Nurseries for premature Infants, 88 air-conditioning equipment, 88 air-conditioning requirements, 88 Ventilating Air Conditioning Guide 1959 O Odors, 61. 76, 91 human body, 61 Oil burners, 487, 490 atomizing, 488, 491 boiler settings, 490 classification, 488, 491 combustion adjustments, 490 combustion efficiency, 490 combustion process, 489 commercial, 490 . controls, 499 domestic, 487 furnace design, 490 gun type, 488 industrial, 490 measurement of efficiency of combus tion, 490 mechanical draft, 488 operating requirements, 489 rotary type, 488, 491 vaporizing type, 489 OH fuel, 471 analysis, 472 calorific value, 473 classification of, 471, 472 combustion index, 473 combustion of, 473, 489 estimating consumption, 498, 537 heating of, 491 piping, 493 storage, 491, 493 Oil storage tanks, 493 One-pipe system, 356, 398 gravity air-vent, 356, 357 hot water, 4, 398 steam, 4, 356 supply riser, 4 unit heater connection, 356 vapor, 357 Opening, openings air supply noises, 343. of, 143 stacks, 146 types of, 145 doors, 145 roof ventilators, 145 skylights, 145 vertical, 143 windows, 145 Operating rooms, 86 conditions, 87 reducing explosion hazard, 88 sterilisation of air in, 88 Orifice discharge, 39, 361 flow, 39 formulas, 40, 631 heating systems, 360 Oraat apparatus, 635 Outdoor air, 61, 62, 176, 196, 663, 661 Outlet, outlets air noises, 343 ceiling, 275 duct approaches, 277 location, 237, 276, 277 perforated, 275, 276 performance, 273, 277 selection, 276 side outlets, 237 slotted, 275 sound absorbers, 346 types, 237, 275 vaned, 275 xvul Outlet, outlets (continued) wall outlets, 275 Overhead distribution, 355, 391, 758 Overhead system, 4, 355, 391, 758 Owen jet dust collector, 75 Oxygen chambers, 91 tents, 90 therapy, 90 Ozone, 62, 78 P Panel beating, 4, 419 application methods, 419 calculation principles, 421-424 control, 432 convection transfer, 422 design of panel, 424-432 electric. 233, 234, 421, 432 embedded piping, 419, 420 hot water, 419, 425 installation, 432 output from surface, 419, 421 piping, 419 radiation transfer, 421 starting system, 420 steam, 419 warm air, 4, 254, 421, 432 Panel radiator, 4 Particle size chart, 74 Perfect gas relationships, 15 Perforated ceilings, 276 Perforated outlets, 275, 276 Perm, 4 Permeability, 4, 129, 131 Permeance, 4, 129-131 pH value, 509, 733, 736, 737 Physical impurities in air, 62 Physiological principles, 61 acclimatization, 64 application to problems, 66 comfort chart, 70 effective temperature, 66 high temperature hazards, 64 thermal interchanges, 62 upper limits of heat, 65 Pipe coils, 207, 209, 671 neat emiarinn 209, 455-457 wall, 209 * * Pipe, piping, 435 application, 451, 452 breeching, 508 - capacity, 209, 364-370, 395, 415, 749 751 . coatings, 744 coil connections, 380 coil output, 209 cold water, 747 - color identification, 12 commercial dimensions, 435-439 conduits for, 385 . connection to heating units, 380 cooling tower, 753 corrosion, 733, 739 covering, 453 design, hot water system, 391 dimensions, 435-439 economical insulation, 459 expansion, 444-448 fittings, 439-450 fitting equivalent, 363,396, 397.416,752, 753 flexibility, 444-448 forced circulation, 391 freezing, 463 friction loss, 393, 394, 396, 415, 749-751 gas, 496, 497 hangers, 448 Index to Technical Data Section Pipe, piping (continued) heat losses, 455-459 hot water heating systems, 391, 412, 414 - hot water supply, 759 in^A dimensions, 436-438 insulation, 388, 453 _ inmilafinn to prevent freezing, 463 low temperature insulation, 463 materials, 435, 743 one-pipe forced circulation, 398 one-pipe gravity, 367 one-pipe vapor. 370 overhead distribution, 355, 391, 758 pressure loss, 36, 38 properties, 435--439, 450 refrigerant, 558, 559 axes, 363, 393, 414 cooling systems, 753 forced circulation, 393-401 gas, 496 high pressure steam, 364-369 high temperature water, 414, 415 hot water forced circulation, 393-401 indirect heating units, 371 one-pipe vapor, aoo orifice systems, 360, 361 pressure drop, 382, 363 tables for steam, 365-367 threading data, 437, 439 two-pipe forced circulation, 397 two-pipe low pressure, 370 two-pipe riser, 366 two-pipe vapor systems, 371 vacuum systems, 371 water supply systems, 747, 749-751 steam distribution, 381-371, 385 steam beating systems, 361-371 supports, 448 surface, 435-439 symbols for drawings, 9 tax, 506 threading practice, 437 tunnels, 387 underground insulations, 465 unit heater connections, 220, 221, 356, water supply, 747 welding, 443 wrougbt-iron, 435 . wrought-steel, 435 Pitot tubes, 44, 630 Plate cell, 346 Plenum absorbers, 346 Plenum chambers, 4 . Pneumatic control systems, 609 Pollen, atmospheric, 81 Pollution of air, 73, 75 Polyphase motors, 641 Ponds, 580 Potentiometer, 4, 628 Power, 4 . Precipitators, 332 Precooling, 265 Premature infant nurseries, 88 Pressure absolute, 4 atmospheric, 1 changes in ducts, 283, 291 dynamic, 4 gages, 4, 629 loss, elbows, 249, 290, 363, 396, 416, 752 loss, water supply piping, 749-751 measurement, 629 barometer, 629 regulators, 371 Pressure (continued) saturation, 4 static, 4 taps, 43 total, 4 vapor, 4 velocity, 4 Prime surface (see Healing surface), 5 Process and product air conditioning, 681 calculations, 690 conditioning and drying, 689 control of chemical reactions, 689 general requirements, 681 humidities, 681-687 laboratories, 690 machining tolerance, 689 moisture content and regain, 687 polished surfaces, 689 proces, 681 temperatures, 681-687 Propeller fan, 303, 306, 311 Protective coatings, 744 Psychrometer, 4. 633 Psychrometrie chart, 17, 27-32, 68 Psychrometiy, 4 Pump, pumps ' - condensate return, 375 high temperature, 414 mechanical circulators, 402, 414 vacuum heating, 375 controls, 376 piston displacement, 376 ' Pyrometer, 4, 629 optical, 629 radiation, 629 R Radial flow fan, 303 Radiant drying, 721 Radiant heating, (see Panel heating) Radiation, 4, 47 . baseboard, 208 ' equation, 48 finned tube, 209 load, 506 ratings, 210 shape factor, 52 thermal, 4 Radiator, radiators, 4, 207-209 baseboard, 208 codes, 207, 210, 760, 761 concealed, 4, 211 ' connections, 381 correction factor, 211 direct, 5 effect of paint, 211 enclosed, 211 heat emission of, 207 output of, 207 panel, 4 ratings, 210 recessed, 5, 209 ' tube, 5, 208 types of, 207 Radioactive contaminants, 81 . Railway air conditioning, 663 air cleaning, 664 air distribution, 664 heating, 663 humidity control, 664 refrigeration, 663 summer systems, 663 temperature control, 664 ventilation, 664 winter systems, 663 Reciprocating compressors, 554 XIX Recording equipment, 612 Rectangular duct equivalents, 287-289 Reducing valves, 371 . Reflective insulation, 98, 100 - Refrigerant, refrigerants, 5, 543 dichlorodifiuoromethane, 542-544 . feeds, 315 monochlorodifluoromethane, 542, 543, 546 pipe size, 558, 559 trichloromonofluoromethane, 543, 548 water, 551 ' Refrigeration, 541, 663, 665 absorption system, 552 accessories, 560 air cycle, 551 basic concepts, 541 complex cycles, 550 compressors, 554-556 condensers (see Condensers), 556 control, 554, 556, 558 coolers, 557 definitions, 541 discharge pressure, 549 ` equipment selection, 560 evaporators, 557 expansion valves, 557 float valves, 558 heat pump, 563-578 load, 167 mechanical, 541, 550, 665, 669 piping, 558, 559 reverse cycle, 541, 563 . ship, 669 simple cycle, 543 Steam jet, 551 subcooling, 550 suction, 548 superheating, 550 symbols for drawing, 9 theory, 541 ton of, 5, 541 types of compressors (see Compres sors), 554, S55 vapor compression cycle, 543 water jacket, 549 Regain, 687 - control of, 687 hygroscopic materials, 6S8 static, 294 Register, registers, (see Grilles) 237, 267, 275, 279, 343 air noises, 343. mechanical furnace systems, 237 noises, 274, 279, 343 selection, 237, 276 Regulator, 489, 490 Reheat, 259, 265 Relative humidity, 3, 14, 27, 133 measurement of, 633 Relief valve, 408, 760 Residence control systems, 625 air conditioning, 625, 653 domestic hot water supply, 759 heating, 625 cooling methods, 258, 651 gravity furnace systems, 258, 509 neat loss problems, 163 hot water heating system, 391 mechanical furnace system, 237 steam heating system, 355 Residential air conditioning, 651 air distribution, 654 application, 652 Heating Ventilating Air Conditioning Guide 1959 Residential air conditioning (continued) central systems, 652 equipment capacity, 651 equipment location, 653 equipment types, 652 gas-nred, 653 noise, 653 operating costs, 654 Resistance thermometers, 628 Resistivity, thermal, 5 Resistors, 231 electric, 5 Return dry. 5 grille, 237, 279 mains, 5, 355, 367 openings, 279 wet, 5 Reversed return system, 5, 397 Ringelmann chart, 76, 635 Roof, roofs heat flow through, 114-118, 121, 178 181, 184 time lag of solar radiation, 191 ventilators, 145 Room air conditioners, 226, 652 air motion, 268, 274 control, 618 coolers, 225, 228 ' cross transmission noise, 352 latent beat, 197, 198 noise level, 341, 347 operating, 86 sensible heat, 197 Rotary dryer, 722 Rotary oil burner, 488, 491 Sabin, 5 S Sanitary ventilation, 83 Saturated air, 1, 14 Saturation, 5 degree of, 5, 14, 17 pressure, 4 Scale, 735 cause and prevention, 733, 735 closed systems, 738 heating systems, 739 high temperature, 739 open systems, 738 temperature, 5 School Systems, 657 air supply,'659 control, 662 cooling, 660-662 design, 657 considerations, 658 criteria, 657 mechanical plant, 659 general considerations, 657 gravity exhaust, 660 heating, 660-662 maintenance, 662, mechanical exhaust, 660 - operation, 662 types, 659-662 venturing, 659 Secondary air, 470, 478, 495 Sensible cooling, 265 . Sensible* heat, 161, 167 gain, 167, 197 loss, 161 Shading of glass areas, 190, 195 Shading screen, 195 Sheet metal gages, 208, 200 Ship heating, ventilation, air tioning, 668 air conditioning, 668, 669 design conditions, 668 factors affecting design, 668 general consideration, 668 heating, 668 insulation of ducts, 668 refrigeration, 669 requirements for space, 668 cargo, 669 living, 668 machinery, 668 storeroom, 669 systems, typical, 669 ventilating, 668 condi Silica gel, 601, 603 Single phase motors, 644 Skylights, 145 Slime, 734, 739 cause and prevention, 739 formers, 734 Slotted outlets, 275 Sludge, 733. 735 . cause and prevention, 735 Smog, 76, S3 Smoke, 5, 73, 75 abatement, 75, 470 density measurements, 635 Smokeless arch, 5 Smokeless combustion, 470 Snow melting, 671 antifreeze characteristics, 676 circulating medium, 677 control, 679 effect of viscosity, 677 design, 671, 680 draining, 679 drifting snow, 680 heat from slab, 671, 974 heating requirements, 671 hydraulic requirements, 677 * installation, 679 internal corrosion, 679 operaring data, 675 pumping head, 677 safety, 679 slab construction, 673, 679 snowfall, 672, 673 testing installation, 679 thermal stresses, 679 Soil specific heat, 95 Solar constant, 5, 169 Solar heat, 169 absorbed by glass, 185 . altitude. 169 calculation tables, 177, 178, 180-194 through shaded windows, 190, 195 rime lag, 191 transmission of, 169 through 184 through gbm block, 188 through roofs, 178 through walls, 178 Solar heat gain, 169 basic principles, 169 design for figured rolled glass, 187 design for flat glass, 187 design for glass block, 188 deviation from design, 190 shading glass, 190, 195 XX Solar radiation, 169 absorption of, 169 magnitude. io Solar water heater, 760 Sol-Air temperature, 178 Solid adsorption, 602 Soot, 73, 470, 483 Sorbents, 601 absorbents, 601, 602 adsorbents, 601 Sorption, 5, 606 - Soand (see Noise), 335 ' absorbers, 344-347 apparatus for measuring, 336, 636 attenuation, 336 control, 335 cross transmission between rooms, 352 general problems, 335 duct absorbers, 344-347 intensity, 336 levels, 335, 341 measurements, 336, 636 outlet absorbers, 346 pressure, 335 unit, 335, 336 Space heaters, 512-514 design, 513, 514 raring, 512-514 Specific gravity, 3 Split systems, 5 - Splitter dampers, 278 Spray apparatus, 579 booths, 706 cooling, 580 cooling ponds, 580 cooling towers, 581-589 dehumidifier, 261, 264, 594 dryer, 723 equipment, 580-582 humidifiers, 591-594 unit air conditioner, 225 8pread, air distribution, 267, 268, 273 Square foot of heating surface, 5 Squirrel-cage induction motor, 641, 642, 646 Stack, stacks, 139, 146, 515 height, 5, 147 Standard, standards (see also Codes), 763 * air, 1 air distribution, 267 atmosphere, 33 Standard air, 1 Static electricity elimination, 689 pressure, 4, 283, 303 regain, 294 Steady now, energy equation, 13, 35 Steam, 5 * coils, 314, 318 distribution piping, 361, 385-389 estimating consumption, 384, 385, 536, 537 flow, 362, 364, 365 flow measurement, 40, 389 heated equipment, 201, 384 hearing systems, 5, 355 condensate return, 355, 388 connections to units, 380 control valves, 382 corrosion, 744 drips, 379 Index to Technical Data Section Steam (continued) flash leg, 380 gravity one-pipe air-vent. 356. 357 vity return, 355 Srtford return, 374 high pressure steam, 364-369 low pressure steam, 364-366 mechanical return, 355 one-pipe, 355, 356 orifice, 360 piping _f_o__r.,I_3_6_1:- oca two pipe, 357 vacuum, 359 vapor, 358 jet type system, 551 meters, 40, 389 panel nearing, 419 pipe capacities, 364-369 properties, 17, 26 reducing valves, 371 requirements, 383, 537 risers, 355, 366, 367 runout, 356 superheated, 5 tqnlea, 18, 26 traps, 5, 376 valves, 382 velocity, 363, 365, 385 ' Stoker, stokers, 485 . classification of, 485 combustion adjustments, 486 combustion process, 488 controls, 498, 499 . furnace design, 487 mechanical, 485 overfeed flat grate, 485 overfeed inclined grate, 485 sizing and ratings, 487 - underfeed, 485 Subatmospheric systems, 360 Summer air-conditioning systems, 167,651 Summer climatic conditions, 170-175 Summer comfort, 70, 71 Superheated steam, 5 Supply mains, 5 Supply openings, 237, 267, 275, 277 measurement of velocities, 632 Supports, pipe, 448 Surface ` condensation, 127, 132, 134, 464 conductance, 2, 95, 98 . coefficients, 98 external pipe, 436-438, 457 . heating, 5 extended, 5 temperature, 124, 423, 512, 628 Suspended unit heater, 218 Symbols, 7, 8 air conditioning, 9-12 for drawings, 9 heating, 9, 10 piping, 9, 10 ventilating, 10, 11 T Tables air changes, 142 air-conditioning temperatures and hu midities, 681-689 air leakage, 140-142 air requirements, 61 air, volume of, 18-21 Tables (continued) air and water mixture, 14 allowable concentration dust, fumes, 79 gases, vapors, 77, 80 altitude, pressure and temperature, 33 aluminum ducts, 299 _ analytical solutions for heat conduction, 58-60 anthracite size, 468, 4 antifreeze, solutions! 676 atmosphere, standard for altitudes, 33 atmospheric gas, 735 atmospheric impurities, 74, 735 attenuation data, lining board, 346 in straight ducts, 344 of branches, 345 of plate absorber, 346 attic ventilation, 122, 136 azimuth angle, 178 black body radiation, 52 boiler ratings, 503-605 bonnet pressure, 258 bonnet temperature, 253, 254 building load factors, 539 calorific value, 368, 473, 475, 478 capture velocities, 701 carbon dioxide maximum, 480 cast-iron boiler rating, 505 ceiling temperature, 159 chimney Hamago survey, 524 chimney draft, 522 chimney efficiency, 520 circular equivalents of rectangular ducts, 288-289 classification of coals, 468 motors, 642 water, 734 climatic conditions, 152, 170 coal analyses, 468 coal classification, 468 codes, 763 coil heat emission, 209 combustible elements and compounds, 478 combustion rates, 507 comfort ranges, 67 condenser design data, 585, 586 conductance, 49, 99-101 air space, 98 conduction problem solution, 54, 58-60 conductivity materials, 48, 99-101, 464 contaminant, allowable in water, 745 contaminant exhaust, 701 convection conductances, 49 conversion equations, 8 ' conveying velocity, 704-706, 711 cooling tower performance, 584 cooling tower pipe size, 753 copper elbow equivalents, 396 copper sheets, 300 copper tube dimensions, 438 copper tube surface, 438 correction factors steam radiator, 211 water radiator, 211 . corrosion resistance, 712, 713 cost of air conditioning, 728 degree days for cities, 529-533, 538, 539 design dry- and wet-bulb temperatures, 152-157. 168, 170-175, 668, 681 design humidity, 681-689 dew point, fuels, 482 draft in chimneys, 522 - draft requirements of appliances, 522 duct attenuation, 344-346 duct combinations, 248, 249 duct gages, 238, 298, 299 duct joints, 298, 299 Tables (continued) duct pressure drop, 257 duct sizing. 239, 242-252 duct velocity, 293 duct weight, 299, 300 dust concentration, 75, 79 dust particle size, 74, 75 efficiency, utilization, 528 elbow equivalent, 290, 363, 396, 416, 752 electric heating systems, 232 electric water heaters, 756 emissivity factors, 52, 98 end reflection, 346 environmental conditions, limits, 65 equivalent length of fittings, 248, 249, 363, 416, 752 equivalent temperature differentials, 180, 182 exhaust, engines, 149 exhaust pipes for machines, 704-706 exhaust velocities, 701, 704-706 fabric filters, 332 fan outlet velocity, 309 fan speed, 309 fitting allowance, 248, 249, 363, 396, 416, 752 fitting dimensions, 450-451 fixture flow, 747 fixture units, 748 flammability of and vapors, 80 flanged fittings surface, 457 flue gas dew point, 482 fluids, compressible, 39 free convection, 50 friction loss, pipe, 382,365, 367,395, 496 friction, valves and fittings, 363, 396, 416, 752 fuel combustion, 478 fuel consumption, 536 fuel oil properties, 472 fumes, concentration, 79 gas analysis, 475 gas piping capacity, 496 gaseous fuel properties, 475 glass block transfer, 123 glass sheet transfer, 123 graphical symbols, 9 grille area correction, 343 . heat absorbed, cooling water, 585 heat conductance, 49, 54, 99-101 heat equivalents, 163 heat flow walls and roofs, 102-121, 182 heat gain ' appliances, 200 coil heat emission, 209 glass, 186-189 . glass blocks, 190-194 insulated cold pipes, 462 occupants, 198, 692 heat loss bare copper pipe, 457 bare steel pipe, 209, 456 basement, 160 floor, 160, 161 pipe coils, 209 radiation, 52 residence, 164-166 room, 164 heat pump heat storage materials, 576, 577 operating cast, 572 sources and anlra, 568 types, 566 heat stress evaluation, 694 heat transmission coefficients, 102-121 building construction, 102-121, 184 doors, 124 glass, 123 roofs, 114-118, 184 walls, 102-109 water heaters, 759 xxt IL Heating Tables (continued) hot water demand, 747, 754, 755 hot water pipe sices, 395 humidities, industrial air conditioning, 681-689 ' hygroscopic materials, 688 incident angle, 177 indoor temperatures, 157, 168, 681-689 inertial separator, 330 infiltration through outside doors, 142 infiltration through walls, 140 infiltration through windows, 141 infla.mmahnit.y_ gaaaa) 80 instantaneous solar heat gain, 186-194 insulation conductivity, 454 insulation factors, 460 insulation thirfrtwaw, 462, 465 inaniatinn to prevent freezing, 462 insulation, underground, 465 intake velocity, 279 iron elbow equivalents, 396 life of equipment, 728 limits for contaminants, 77-80 load factors, 539 maintenance cost, 729 maximum allowable concentrations dusts, 79 ' ' flammable gases, 77, 80 fumes, mists, 79 gases, 77, 80 - vapors, 77, 80 metal gages for ducts, 238, 298, 299, 708, 709 meter performance, 752 minimum- outdoor air requirements to remove odors, 61 moist air factors, 14 moisture content for materials, 688 moisture regain, 688 moisture transfer, 131 motor classification, 642 motor current, 643 . motor design limits, 640 motor drive applications, 644 motor horsepower, 640 - motor ratings, 645 motor speed range, 640 - motor starting methods,-645 motor torque, 644 motor voltage, 640 noise levels, 341 octave frequency Handa 335 ' oil fuel specifications, 472 oil beat value, 473 operating cost, 728-730 operating hours, 655, 730 orifice capacities, 361 outdoor air requirement, 61, 176 outlet velocities, 309 outdoor temperatures, 152, 156, 170 owning and operating cost, 728, 729 panel resistance ceiling, 427, 428 floor, 429 floor covering, 430' particle size, 74, 75 particulate matter, size, 74 perimeter extended plenum branch duct capacity, 245-247 size, 250 perimeter loop system diffuser area, 241 duct capacity, 243 feeder diameter, 239 perimeter radial system feeder duct capacity, 242 perimeter system return duct capacity, 250 - permeability to vapor, 131 ' physiological response to heat, 64 pipe application, 451 Ventilating Air Conditioning Guide 1959 Tables (continued) pipe capacity, 365^367, 370, 395, 493, 496, 559, 560 pipe correction factor, 678 pipe covering factors, 460 pipe dimension, 436 pipe fittings, 440 dimensions, 441-450 pressure ratings, 440 pipe insulation, 454 pipe roughness, 37, 287 pipe surface, 436 thermal stress, 450 pipe volume, 404, 436 pressure loss * area change, 291 ducts, 257 elbows, 290, 363, 396, 416, 752 fittings, 248. 249, 363, 396, 416, 752 refrigerant line, 559, 560 registers, 255, 256 return intake, 279 steam pipe, 362 velocity, 291 properties of air, 18-21 antifreeze solutions, 676 dichlorodifluoromethane, 544 fuel oil, 472 gaseous fue!s,-475 moist air, 18-21 monochlorodifluoromethane, 546 steam, 26 trichioromonofluoromethane, 548 trichiorotrifiuoromethane. 549 water, 22-25, 410 radiation, black body, 52 radiation factors, 52, 211 radiation problem solution, 53 radiator heat loss correction factors, 211 radiator sizes, 208, 209 rating air-conditioning units, 228 rating steel boilers, 503, 504 ratio of specific heats, 39 refrigerant properties, 544-549 refrigerant line capacity, 559, 560 refrigeration equipment selection, 561 regain of hygroscopic materials, 688 register pressure loss, 255, 256 register temperature, 253, 254 requirements for fuel oil, 472 resistance, ventilated attics, 122 resistor heat output, 236 return pipe capacities, 362, 367 room temperature differential, 159 saturated steam, 26 screen mesh, 75 shading effect, 195 sheet metal gages for ducts, 298, 299, 708, 709 ship design conditions, 668 skylights, 123 dime control, 739 slime formers, 734 smoke chart numbers, 635 snowfall data, 672 snow melting systems, 672-674 sodium dichromate, 741 soil conductivity, 95 sol-air temperature, 179 solar altitude, 177, 178 ' solar, azimuth, 178 solar declination, 178 solar heater design, 761 solar heat gain, 177-184, 186-195 solar radiation, 177 sound attenuation, 344-346 sound level, 339, 341, 351 specific gravity factors, 497 specific heat of compressible fluids, 39 specific heat ratio, 39 xxii Tables (continued) spray pond design data, 580 steady-state conduction problems, 51 steam consumption buildings, 385; 537 equipment, 384 water heating, 385 steam conversion factors, 211 steam pipe capacities, 365-367, 370 steam pressure, 26 steel boiler ratings 503, 504 summer climatic conditions, 170-175 summer design conditions, 168, 170 surface conductance, 49, 96, 98 temperature, bonnet, 253, 254 temperature differential, 159, 180, 182, 183 temperature, industrial air-conditioning, 681-689 . temperature, indoor, 157, 168, 681-689 temperature limit for men, 65 temperature, oil preheating, 491 ' temperature range, 168 temperature, summer, 170-175 temperature, winter, 152 thermal conduction problems, 54, 53-60 thermal conductivity, 47, 95, 404 thermal convection conductance, 49 thermodynamic properties moist air, 18-21 ' . water, 22-25 . transmittance, 186-188 unit conditioner rating, 228 unit fuel consumption, 536 unit ventilator capacities, 215 upper temperature limits, 65 vanes in elbows, 290 vapor transfer, 133 velocity constant for airjet, 269 velocity, return intake, 279 ventilation rates for equipment, 702 704-706, 708-710 * ventilation standards, 176 viscosity conversion, 677 viscosity effect on pump, 678 warm air ducts, 239-250 . warm air fittings, 248, 249 water analyses. 734, 745 water fixture flow, 748 water main temperatures, 595 ' water meter performance, 752 water pipe capacities, 395 water requirements, 655, 754, 755 weight of air, 18-21 ' weights of ducts, 299, 300 wet collectors, 331 ' winter climatic conditions, 152 winter design temperatures, 152, 157 Tank, tanks expansion, 403-406 ' oil storage, 493 . ' Tax, pipe, 506 ' - Temperature, temperatures . absolute, 5, 16 attic, 158 automatic control, 609, 664, 665, 669 basement, 160 body, 62 ceiling, 158 control for railway passenger car, 664 control service water, 760 design wet-bulb, 168, 170, 587 dew-point, 5, 15 differential, 181 dry-bulb, 5 drying, 718 effective, 5 floor, 158 ground, 159 Index to Technical Data Section Temperature, temperatures (continued)- hazard, 64 indoor, 157, 161, 668 . .. - - . ceilings, high, 158 - proper level, 158 \. mean radiant, 65, 66, 423, G34 -- measurement, 627 '' pyrometers, 629 . thermocouple, 627 thermometers, 627 outdoor, 153j 170 proper level, 158 .. scales, 5 ' surface, 124, 512, 628 . thermodynamic wet-bulb, 14 ' unheated spaces, 159 1 water main, 595 - well water, 596 ' wet-bulb, 5 .' Terminology, 1 Test methods, 627, 703 ' _ Testing codes, (see also Standard*), 763 Therapy ' cold, 89 fever, 89 oxygen, 90 , Therm, 5 .' ' Thermal conductance; 93 conduction equation, 47 ' conductivity, 47, 93 * convection, 47, 48 convection equation, 48 expansion of pipe, 444 integrator, 634 interchanges of body, 62 radiation equation, 48 resistance, 5, 93 steady-state conduction problems, 54 transmittance, 6, 161 unit conductances for convection, 46 Thermocouples, 627 . Thermodynamics, 13 . air and water mixture, 13, 1C, 18 ' moist air, 13 * laws, of, 6, 13 wet-bulb temperature, 14 " Thermometers, 627 * alcohol, 627 dry-bulb, 627 . globe, 634 Kata, 632 mercurial, 627 resistance, 628 stem correction, 627 wet-bulb, 633 ' -'' ' . Thermostat, 6, 609, 612 room, 612 Time lag through walls and roofs, 19! Ton of refrigeration, 5 Total heat, 3 Total pressure, 4 Tower, towers, 581 atmospheric, 581 cooling, design, 582, 585 - cooling, performance, 582 location, 588 mechanical draft, 581 natural draft, 581 selection, 587 spray cooling, 581 Transmission coefficient for heat, 3 Transmission (continued) .. . . , . heat losses, 160-162 - . solar heat, 178 ;. . Transmittance, thermal, 6- - : ' . Transportation air conditioning, 663 temperature and humidity control, 664, 665, 669 . Trap, traps, 376 .. alternating receiver, 379 ' . automatic return, 357, 358, 379 .. bucket, 377, 378 float, 376, 377; impulse, 377 " installation, 379 steam, 376 ;. . thermostatic, 377 ' . Treatment of disease, 83, 86 Tropical air cooling, 85 Tube radiator, 5 . Tunnel dryer, 721 Tunnels, pipe, 387 ' Turning vane, 278, 290 Two-pipe system, 6, 357, 370, 397 ' . U Ultra-violet light, 62, 76, 85 1 Underfeed stoker, 485, 486 Underground pipe insulation, 388, 465 Unheated space temperatures, 159 Unit, nnits air cleaners, 323, 32) air conditioners, 223 application, 227 cooling, 228 " dehumidifying, 225 humidifying, 224 ratings, 227 remote units, 223, 224 room, 226 sound isolation, 228 types, 223 air coolers, 228 defrosting, 229 design, 223 ' performance, 229 ratings, 229 types of, 228 air filters, 323, 329 British thermal, 1 dehumidification, 225 direct-indirect heating, 2 fuel consumption, 536 heaters, 217 . application, 217 automatic control, 220 classification, 217 control, 220 direct-fired, 217 electric, 217 heating medium, 217 location, 219 maintenance, 221 outlet velocity, 216 piping connections, 220, 221 ratings, 219 sound level, 219 temperatures, 219, 220 types of, 217-219 humidifiers, 591 types of, 591 induction, 262, 283 noise measurement, 335 systems, 213, 223 ventilators, 213 ' air exhaust vents, 216 applications, 215 capacity, 214, 215 XXIII Unit, units (continued) - . ; vr clarification, 213 'j* * control, 215 location, 216 . mechanical cooling, 216 ' ..i-' '. . ratings, 213, 215 ; selection, 215 window, 216 . . downdraft protection, 216, Unitary equipment, 223 ; . . definitions, 223 Up-feed system, 6 ; .- , -V Vacuum - . .. cooling units, 551 ; heating pumps, 375 . control, 376 . piston displacement, 376 -- . heating system, 6, 359 .- down-feed, 359 unit heater connection, 219,220 .. V / . Valve, valves, 382, 416, 441, 612 automatic, 612 check, 443 control, 382 . expansion, 557 gate, 382, 442 . globe, 443 reducing pressure, 371, 443 relief, 403, 443 . thermostatic air, 357 . .. 'r-' . Vane, vanes, 267, 273, 278, 290 ratio, 6, 267 : . turning, 278, 290 ' Vaned outlets, 278 converging, 273 diverging, 273 ' " ' " Vapor, vapors, 73 .' adsorption, 328 barrier, 128, 131, 134 flammable, 78 . heating systems, 6, 358 pressure, 4 ' transfer, 128, 607 transmission, 128 Vaporizing oil burner, 489 Velocity, 6 '' capture, 701 ' coil, 317-319 conveying, 704-706 " duct, 292, 295, 704 exhaust intakes, 279, 704-706 high velocity system, 295 hood, 704 operating, 292, 309, 701, 704-706 pressure, 4 reduction method, 293 return grilles, 279 unit heater, 219 Vena contract*, 43 Venetian blinds, 125 . , ' Ventilation, 6, 61, 139, 168, 176, 196, 665, 668 animal shelters, 147, 148 attic. 121, 136 crawl spaces, 136 dairy stables, 147 garages, 148 living space, 136, 176 natural, 143 general rules, 146 outdoor air, 61, 176, 196, 664, 665 passenger bus in summer, 665 railway passenger car, 663 Heating Ventilation {continued) rules, 146 ship. 666 symbols for drawings, 9 tanks, 709 walls, 137 wind forces, 139 Ventilator, ventilators, 145 control, 146 roof, 145 unit, 213 control, 215 Vertical blow unit heater, 218 Vertical openings, 143, 145 sealing of, 143 Vibration, machine, 352 Viscous filters, 324 impingement, 324 Vitiation of air, 61 Volume control, 278 furnace, 487, 490 specific, 6 . W Wall, walls heat flow through, 102-109, 178, 195 heat transfer coefficients, 47, 102-109 infiltration through, 139 time lag of solar radiation, 191 Warm air gravity heating system, 6, 258 mechanical (forced) systems, 237 air distribution, 237 automatic control, 253, 625 ceiling panel system, 254 cooling methods. 651 continuous circulation, 253 dampen, 239 design procedure, 240, 250 ducts, 239 fans, 509 filtem, 509 ' fura&Qe, 509 heavy duty, 510 selection, 253 humidification, 512 large systems, 250 perimeter system, 240-247 pressure drop, 257 panel heating, 254 registers and grilles, 237 Ventilating Air Conditioning Guide 1959 Washer, washers, 592 air, 1, 592-594 cooling, 594 dehumidification, 594 humidification, 594 Water analysis, 734 atmospheric cooling equipment, 579-681 characteristics,- 733 classification, 733 . coils, 314, 758 content of radiators, 404 control temperature service, 760 cooled condenser, 556 . cooling tower, 581 . corrosion treatment, 735-743 demand, 748, 753-755 faucets, 747 fittings, 1q6S, 752, 753 fixtures, 748 fixture units, 748 formed deposits, 733 heater coal-fired, 755 electric, 756 indirect, 757 solar, 760 heating, 753, 755 . in building material, 128 load, 747 make-up, 588, 738 - maximum main temperature, 595 meters, 752 mineralised, 734 properties of, 22, 734 services, 747 ' storage capacity, 753 supply piping, 760 arrangement, 758 . temperature control, 759 thermodynamic properties of, 22 treating chemicals, 733, 744 well temperatures, 596 * Water vapor, 13, 18-21. 127 condensation in buildings, 127 saturation pressure, 13, 22 specific enthalpy, 2 specific volume, 6, 22 surface condensation, 132 Weather conditions design outdoor, 151, 168 Welding, 443 wa-BsJt temperature, {see ismpera- ture) 5, 14, 587 Wet cup, 130 - Wet return, 5, 355 Wind, winds forces, 139, 143 due to stack effect,'139. natural draft equipment, 515 selection of, velocity, 152, 170 Window, windows coefficients of transmission, 123 - leakage, 140 solar radiation through, 184 Winter air conditioning system, 259, 651 comfort chart, 67,. 70 freezing equipment, 589 Wound rotor motor, 641 Wrought-iron pipe, 435 Wrought-steel pipe, 435 Y Year-roand air-conditioning system, 259, 651 air flow in, 261, 654 control methods, 260, 619-623, 625 design procedure, 259, 265, 651 equipment arrangement, 266 installation, 259, 651 . location of apparatus, 266, 653 residential, 977 selection, 265, 651 Zero, absolute, 1 Z Zone, zones control, 260, 618, 623, 624 evaporative regulation, 63 metabolic regulation, 63 thermal neutrality, 67 vaso-motor regulation, 63 Zoning, 260, 618, 623 , control, 280, 618, 623 hot water system, 623 reheat, 280 volume control, 260 - XXiv CHAPTER TERMINOLOGY Glossary of Physical and Heating, Ventilating, Refrigerating and Air Conditioning Terms Used in the Text Absolute Zero: The sero from which absolute temperature is reckoned. Approximately --273.15 C or --459.67 F. These values were established by the Tenth General Conference on Weights and Measured (1954). . Absorbent: A sorbent which changes physically or chemi cally, or both, during the sorption process. Absorption: The action of a material in extracting one or more substances present in an atmosphere or mixture of gases or liquids; accompanied by physical change, chemical change, or both, of the sorbent. Acceleration: The time rate of change of velocity, i.e., the derivative of velocity with respect to time. In the cgs system the unit of acceleration is the centimeter per (second) (second); in the fps system the unit is the foot per (second) (second), do ~ 0 = df Acceleration Dae to Gravity: The rate of gain in velocity of a freely falling body the value of which varies with latitude and elevation. The international gravity standard has the value of 980.665 cm per (sec) (sec) or 32.174 ft per (sec) (sec) which is the actual value of this acceleration at sea level and about 45 deg latitude. Adiabatic: An adjective descriptive of a'process such that no heat is added to,.or taken from, a substance or system under going the process. . ' Adsorbent: A sorbent which does not change physically or chemically during the sorption process. Adsorption: The action, associated with surface adherence, of a material in extracting one or more substances preseot in an atmosphere or mixture of gases and liquids, unaccompanied by physical or chemical change. Commercial adsorbent ma terials have enormous internal surfaces. Aerosol: An assemblage of small particles, solid or liquid, suspended in air. The diameters of the particles may vary from 100 microns down to 0.01 micron or less, e.g., dust, fog, smoke. Air Cleaner: A device designed for the purpose of removing airborne impurities such as dusts, gases, vapors, fumes, ana smokes. (Air cleaners include air washers, air filters, electro static precipitators, and charcoal filters.) Air Conditioning: The process of treating air so as to con trol simultaneously its temperature, humidity, cleanliness, and distribution to meet the requirements of the conditioned space. Air, Dry: In psychrometry, air unmixed with, or containing no, water vapor. Air, Saturated: A mixture of dry air and saturated water vapor, all at the same dry-bulb temperature. Air, Standard: Air with a density of 0.075 lb per cu ft and .an absolute viscosity of 0.0379 X 10~f lb mans per (ft) (sec). This is substantially equivalent to dry air at 70 F and 29.92 iq. Hg barometric pressure. Air Washer: An enclosure in which air is drawn or forced through a spray of water in order to cleanse, humidify, or debumidify the air. Anemometer: An instrument for measuring the velocity of a fluid. . Aspect Ratio: In air distribution outlets, the ratio of the length of the core of a grille, face, or register to the width. In rectangular ducts, the ratio of the width to the depth. Atmospheric Pressure: The pressure of the atmosphere to be measured by means of the barometer. Standard Atmospheric Pressure or Standard Atmosphere is exactly 1,013,250 dynes per 8q cm by recent action of the Tenth General Conference on Weights and Measures (1954). It is approximately the pres sure exerted by a column of mercury 76 cm high at standard gravitational acceleration, 980.665 cm per (sec) (sec), the mercury having a density of 13.5951 g per cu cm. It is equiva lent to 14.696 psi or 29.921 in. Hg at 32 F. Baffle: A surface used for deflecting fluids, usually in the form of a plate or wall. Blast Heater: A set of beat transfer coils or sections used to heat air which is drawn or forced through it by a fan. Blow (throw): In air distribution, the distance an air stream travels from an outlet to a position at which air motion along the axis reduces to a velocity of 50 fpm. For unit heaters, the distance an air stream travels from a heater without a perceptible rise due to temperature difference and loss of velocity. - Boiler Heating Surface: All of the surface of the heat-trans fer apparatus in contact on one side with the water or wet steam being heated and on the other side with the gas or re fractory being cooled, in which the fluid being heated forms part of the circulating system, this surface to be measured 00 the side receiving heat. (Stationary Steam-Generating Units, ASMS Pouter Test Codes, PTC 4-1946.) Direct Heating Surface is generally understood to be the boiler heating surface subject to direct radiation from the sur face of the grate, or from the surfaces of oil or gas burners. Indirect Healing Surface is' the boiler heating surface within the flues. Boiler Horsepower: The equivalent evaporation of 34.5 lb of water per hr from and at 212 F. This is equal to a heat out put of 970.3 X 34:5 = 33,475 Btuh. British Thermal Unit (Btn): The Btu is defined as 778.177 foot-pounds if it is related to the IT calorie in such a way that 1 IT caloric per (kg) (C deg), -- 1 Btuj>er (lb) (F deg), with 1 lb = 453.5924 g. The Ninth General Conference on Weights and Measures (1948) recommended the absolute joule as the fundamental unit of energy thereby, in effect, liquidating the old international electrical units. This calls for a redefinition of the International Tables calorie (IT cal) according to the following conversion factor: 4.18684 joule per IT calorie. Calorie (Gram Calorie): The IT gram calorie is equivalent to 0.003968 Btu. (See definition of Btu.) Central Fan System: A mechanical indirect system of heat ing, ventilating, or air conditioning, in which the air is treated or handled by equipment located outside the rooms served, usually at a central location, and is conveyed to and from the rooms by means of a fan and a system of distributing ducts. (See Chapter 19.) s' Chimney Effect: The tendency of air or gas in a duct or other vertical passage to rise when heated due to its lower density compared with that of the surrounding air or gas. In buildings, the tendency toward displacement (caused by the difference in temperature) of internal heated air by un- heated outside air due to the difference in density of outside and inside air. , ' Coefficient of Performance (Heating): The ratio of the total instantaneous useful heating effect produced by a heat pump system at stated conditions, to the heat equivalent of the total energy input rate required to drive or operate the system. Coefficient of Performance (Cooling): The ratio of the instantaneous refrigeration effect produced by a heat pump 1 2 CHAPTER 1 1959 Guide ' at stated conditions, to the heat equivalent of the total input rate required to drive or operate the system, ort Air Conditioning: The process of treating air so as rol simultaneously its temperature, humidity, cleanliud distribution to meet the comfort requirements of .cupants of the conditioned space. (See also general tion of Air Conditioning on page 1 of this chapter.) "omfort Line: A line on the comfort chart showing relation between the effective temperature and the percentage of adults feeling comfortable. ' Condensate: The liquid formed by condensation of a vapor. In steam heating, water condensed from steam: in air con ditioning, water extracted from air, as by condensation on the cooling coil of a refrigeration machine. Condensation: The process of changing a vapor into liquid by the extraction of neat. Condensation of steam or water vapor is effected in either steam condensers or in debumidifying coils and the resulting water is called condensate. Conductance, Surface ((/nit): The amount of heat trans ferred by radiation, conduction, and convection from unit area of a surface to the air or other fluid in contact with it, or vice versa, in unit time for a unit difference in temperature between the surface and the fluid. The common unit is: Btu per (hour) (square foot) (Fahrenheit decree). Symbol /. The temperature of the fluid should be taken in a plane sufficiently far from the surface that it will not be affected by the temper ature of the surface. Conductance, Thermal: The time rate of heat flow through unit area of a body, of given sise and shape, per unit tempera ture difference. Common unit is: Btu per (hour) (square foot) (Fahrenheit degree). Symbol C. Conduction, Thermal: The process of heat transfer through a material medium in which kinetic energy is transmitted by the particles of the material from particle to particle without gross displacement of the particles. Conductivity, Thermal: The time rate of heat flow through unit area of a homogeneous substance under the influence of a unit temperature gradient. Common units are: Btu per (hour) (square foot) (Fahrenheit degree per inch)'. Symbol k. Conductor, Thermal: A material which readily transmits heat by means of conduction. Convection: The motion resulting in a fluid from the differ ences in density and the action of gravity. In heat transmis sion this meaning has been extended to include both forced and natural motion or circulation. Convective Heat Transfer: The transmission of heat by either natural or forced motion of a fluid (liquid or gas). Convector: An agency of convection.. In heat transfer, a surface designed to transfer its heat to a surrounding fluid largely or wholly by convection. The heated fluid may be re moved mechanically or by gravity (Gravity Convector). Such a surface may or may not be enclosed or concealed. When con cealed and enclosed the resulting device is sometimes referred to as a concealed radiator. (See also definition of Radiator.) (See also Chapter 14.) Decibel: A unit used to express the relation between two amounts of power. By definition the difference in decibels between two powers P\ and Pi , Pt being the larger, is: db difference a 10 logj*/**//*!. ' In acoustics the threshold of hearing at 1,000 cycles per see has been standardized at I0~u watts per sq cm. If Pt is the. power in watts per square centimeter of a measured sound, then 10 logi*Pt/10~" is the db difference above the threshold and is known ns the intensity level. This is a definite recognized way of describing the intensity of a sound. Declination of Son: The angle above or below equatorial plane. It is plus if north of the plane, and minus if below. Celestial objects are located by declination. Degree Day: A unit, based upon temperature difference and time, used in estimating fuel consumption and specifying nominal heating load of a building, in winter. For any one day, when the mean temperature is less than 65 F, there exist as many degree days as there are Fahrenheit degrees difference in temperature between the mean temperature for the day and 65 F. Dehwnidlfy: To reduce by any process,-the quantity of water vapor within a given space. Dehydrate: To remove water in all forms from matter. Liquid water, hygroscopic water, and water of crystallisation or water of hydration are included. Density: The ratio of the mass of a specimen of a substance to the volume of the specimen. The mass of a unit volume of a substance. When weight can be used without confusion, as synonymous with mass, density is the weight per unit volume. ' Dew Point: See Temperature, Dew Point. Diffusivity, Thermal: Thermal conductivity divided by product of density and specific heat *= fc/pc. Expressed in units of square feet per hour. Direct-Indirect Heating Unit: A heating unit located in the room or space to be heated and partially enclosed, the enclosed portion being used to heat air which enters from outside the room. Direct-Return System (Hot Water): A hot water system in which the water, after it has passed through a heating unit is returned to the boiler along a direct path so that the total distance traveled by the water is the shortest feasible, and so that there are considerable differences in the lengths of the several circuits composing the system. Down-Feed One-Pipe Riser (Steam): A pipe which carries steam downward to the Heating units and into which the con densate from the heating units drains. Down-Feed System (Steam): A steam heating system in which the supply mains are above the level of the beating units which they serve. Draft: A current of air. Usually refers to the pressure differ ence which causes a current of air or gases to flow through a flue, chimney, heater, or space. * . Draft Head (Side Outlet Enclosure): The height of a gravity convector between the bottom of the heating unit and the bottom of the air outlet opening. (Top Outlet Enclosure): The height of a gravity convector Detween the bottom of the heating unit and the top of the enclosure. Drip: A pipe, or a steam trap and a pipe considered- as a unit, which conducts condensation from tne steam side of a piping system to the water or return side of the system. Dry: To separate or remove a liquid or vapor from another substance. Tbe liquid may be water, but the term is also used for the removal of liquid or vapor forms of other substances. Dust: An air suspension (aerosol) of solid particles of any material. (See also Chapter 7.) Enthalpy: A term used in lieu of total heat or heat content. Expressible in Btu per pound. Mathematically defined as h = 'u + pv/J. When a change occurs at constant pressure, as when water is boiled, the change in enthalpy is equal to ' the heat added, in this case latent neat. Enthalpy, Free: A thermodynamic property which serves as a measure of the available energy of a system with respect to surroundings at the same temperature and same pressure as that of the system. No process involving an increase in available energy can occur spontaneously. Enthalpy, Specific: A term sometimes applied to enthalpy per unit weight, the English unit being Btu per pound. Entropy: Tbe ratio of the heat added to a substance to the absolute temperature at which it is added. Mathematically, for a reversible process, dS dQ/T or S * / dQ/T. These formulas are applicable when temperature is not constant. During a reversible adiabatic change, entropy is constant. During a reversible isothermal change, the heat absorbed by the substance is equal to the product of tbe ab solute temperature of the substance and its change of entropy. Entropy, Specific: A term sometimes applied to entropy per unit weight, the English unit being Btu per (Fahrenheit de gree, absolute) (pound). Equivalent Evaporation: The amount of water a boiler would evaporate, in pounds per hour, if it received feed water at 212 F and vaporized it at the same temperature and corre sponding atmospheric pressure. Fan Furnace System; See Warm Air Heating System. Fog: Suspended liquid droplets generated by condensation from the gaseous to tne liquid state, or by breaking up a liquid into a dispersed state, such as by splashing, foaming, and atom ising. (See also Chapter 7.) Terminology 3 Force: The action on a body which tends to change its rela tive condition as to rest or motion. - Fumes: Smoke; aromatic smoke; odor emitted, as of flowers; a smoky or vaporous exhalation, usually odorous, as that from . concentrated nitric acid. The word fumes is so broad and in clusive that its usefulness as a technical term is very limited. Its principal definitive characteristic is that it implies an odor. The terms vapor, smoke, fog, etc., which can be more strictly defined, should be used whenever possible. Also defined as solid particles generated by condensation from the gaseous state, generally, after volatilisation from molten metals, etc., and often accompanied by a chemical reaction such as oxidation. Fumes fiocculate and sometimes coalesce. (See also Chapter 7.) Furnace: That part of a boiler or warm air heating plant in which combustion takes place. Also a complete beating unit for transferring heat from fuel being burned to the air supplied to a heating system. Furnace Volume (Toioi): The total furnace volume for horizontal-return tubular boilers and water-tube boilers is the cubical contents of the furnace between the grate and the first plane of entry into or between tubes. It therefore includes the volume behind the bridge wall as in ordinary horizontalreturn tubular boiler settings, unless manifestly ineffective (i.e., no gss flow taking place through it), as in the case of waste-heat boilers with auxiliary coal furnaces, where one part of the furnace is out of action when the other is beingused. For Scotch or other internally-fired boilers, it is the cubical contents of the furnace, flues, and combustion cham ber, up to tbe plane of first entry into the tubes. (ASAf Power Test Codes, Series 1929.) Grate Area: The area of the grate surface, measured in square feet, to be used in estimating the rate of burning fuel. This area is construed to mean the area measured in the plane of the top surface of the grate, except that with special fur naces, such as those having magazine feed, or special shapes, the grate area shall be the mean area of the active part of the fuel bed taken perpendicular to the path of. the gases through it. For furnaces having a secondary grate, such as those tn double-grate down-draft boilers, the' effective area shall be taken as the area of the upper grate plus one-eighth of the area of the lower grate, both areas being estimated as pre viously defined. Gravity, Specific: The ratio of the mass of a unit volume of a substance to the mass of the same volume of a standard substance at a standard temperature. Water at 39.2 F is the standard substance usually referred to. For gases, dry air at the same temperature and pressure as the gas, is often taken as the standard substance. . Gravity Warm Air Heating System: See Warm Air Heating System. Head, Dynamic: Same as Total Pressure expressed in height of liquid. . Heat: That form of energy "which transfers from one system to another, by virtue of the temperature difference which exists between the two systems, when they are placed in com munication. Heat, Humid: Ratio of increase of enthalpy per pound of dry air to rise of temperature under conditions of constant pressure and constant humidity ratio. . Heat, Latent: A term used to express the energy involved in a change of state. '. Heat, Sensible: A term used in heating and cooling to in dicate any portion of beat which changes only the temper ature of the substances involved. Heat of the Liquid: The increase in enthalpy per unit weight of a saturated liquid as its temperature increases from a chosen base temperature. For water, the base temperature is usually taken as 32 F. Heat Pump: In year-round air conditioning, refrigeration equipment used in such manner that heat is taken from a heat source and given up to the conditioned space when beating service is wanted, and is removed from the space and dis charged to a heat sink when cooling and dehumidification are desired. Heat, Specific: The heat' absorbed (or given up) by a unit mass of a substance when its temperature is increased (or decreased) by 1 deg. Common Units: Btu per (pound) (Fahren heit degree), calories per (gram) (Centigrade degree). For gases, both specific heat at constant pressure (e,) and specific heat at constant volume (c.) are frequently used. In air con ditioning, c, is usually used. Heat Stress Index: A numerical index of the relative degree of heat stress imposed by various combinations of metabolic heat production with environmental radiant heat, air temper ature, air velocity, and moisture content of the air. A young man in good physical condition and acclimatized to beat can withstand a total heat load having an HSI = 100 for eight hours a day of simple physical work without suffering undue physiological strain. Older men and others with physiological impairments and men engaged in more exacting work require lower HSI values. Heat, Total: See Enthalpy. Heat Transmission, Coefficient: Any one of a number of coefficients used in the calculation of heat transmission by conduction, convection, and radiation, through various mate rials and structures. (See thermal conductance, thermal con ductivity, thermal resistance, thermal resistivity, thermal transmittance, etc.) Heating Element, Electric: A unit assembly consisting of a resistor, insulated supports, and terminals for connecting the resistor to electric power. Heating Unit, Electric: A structure containing one or more heating elements, electrical terminals or leads, electric insula tion, and a frame or casing, all assembled together in one unit. Hot Water Heating System: A heating system in which water is used as the medium by which heat is carried from the boiler to the heating units. Humidify: To increase, by any process, the density of water vapor within a given space. Homidistat: A regulatory device, actuated by changes in humidity, used for the automatic control of relative humidity. Humidity: Water vapor within a given space. Humidity, Absolute: The weight of water vapor per unit volume, pounds pier cubic foot, or grams per cubic centimeter. Humidity, Relative: The ratio of the mol fraction of water vapor in a mixture to the mol fraction of water vapor in satu rated air at the same dry-bulb temperature and barometric pressure. (See discussion in Chapter 3.) Also defined in various texts as the ratio of the actual partial pressure of the water vapor in a space to the saturation pressure of pure water at the same temperature. Humidity Ratio: In a mixture of water vapor and air, the weight of water vapor per pound of dry air. Symbol W. Also called Specific Humidity. Humidity, Specific: See Humidity Ratio. . Hygrostat: Same as Humidiitat. Inch of Water: A unit of pressure equal to the pressure exerted by a column of liquid water 1 in. high at a standard temperature. The standard temperature is sometimes taken as 0 C and sometimes as 62 F. One inch of water at 62 F -- 5.197 lb per sq ft. Insulation (TAermai): A material having a relatively high resistance to heat flow, and used principally to retard the flow of heat. Isobaric: An adjective used to indicate a change taking place at constant pressure. - Isothermal: An adjective used to indicate a change taking place at constant temperature. , Load, Estimated Design: In a heating or cooling system, the sum of the useful heat transfer, plus heat transfer from or to the connected piping, plus heat transfer occurring in any auxiliary apparatus connected to the system. The units are Btu per hour or, in heating, equivalent direct radiation (EDR). Load, Estimated Maximum: 1q a heating or cooling system, the Calculated maximum heat transfer that the system will be called upon to provide. ' Manometer: An instrument for measuring pressures; es sentially a U-tube partially filled with a liquid, usually water, mercury, or a light oil, so constructed that tbe amount of dis placement of the liquid indicates the pressure being exerted on the instrument. - 4 CHAPTER 1 1959 Guide Mass: A measure of the inertia of a body. It also measures the quantity of matter in a body. Since the only general prop erty of a given portion of matter that cannot be changed is its inertia, it is this property by which quantities of matter are defined. Two bodies which have equal inertias' are said to have equal masses, or to contain equal quantities of matter. (This definition fails at velocities approaching the velocity of light.) The niaaa of a body is numerically equal to the ratio of the force required to give the body a given acceleration, to the acceleration, m = F/a. The common units of mass are the gram and the pound. Mechanical Equivalent of Heat: The quantity of mechanical energy equal to one unit of heat. J * 778.177 ft-lb per Btu = 4.1858 X 10* ergs per g-cal. Medium, Heating: A substance such as water, steam, air, or furnace gas used to convey heat from the boiler, furnace, or other source of heat or energy to the heating unit from which the heat is dissipated. Micron: A unit of length, the thousandth part of 1 mm or the millionth of a meter. Millimeter of Mercury: A unit of pressure equal to the pres sure exerted by a column of mercury 1 mm high at a temper ature of 0 C- One millimeter of mercury at 0 C 1.934 X 10"* psi. Mol: A weight of a substance numerically equal to its mo lecular weight. If the weight is in pounds the unit is a Pound Mol, in grams the unit is a Cham Mol. For perfect gases the volume of 1 mol is constant for all gases at the same temper ature and pressure. For real gases this is approximately true at moderate pressures. At 32 F and zero-pressure the value of the product, pressure times specific volume, is 359.045 0.006 atmosphere cubic feet (atm ft*), for 1 mol of any gas. For dry air at 32 F and standard atmospheric pressure, the specific volume is 358.83 cu ft per mol (ft* per mol). One-Pipe Supply Riser (Steam): A pipe which carries 8team vertically to a heating unit, and which also carries the condensate from the heating unit. In an up-feed system, steam and condensate flow in opposite directions; in an overhead or down-feed system, they flow in the same direction. One-Pipe System (Steam): A steam heating system in which a single main serves the dual purpose of supplying steam to the heating unit and conveying condensate from it. Ordinarily to each heating unit there is but one connection which must serve as both the supply and the return, although separate supply and return connections may be used. (Hot Water)--A hot water system in which the cooled water from the beating units is returned to the supply main. Consequently, the heating units farthest from the boiler are supplied with cooler water than those near the boiler in the same circuit. Overhead System: Any steam or hot water system in which the supply main is above the heating unit. In a steam system the return must be below the heating units; in a water system the return may be above or below the heating units. Panel Heating: A heating system in which heat is trans mitted by both radiation and convection from panel surfaces to both air and surrounding surfaces. Panel Radiator: A heating unit placed on or flush with a flat wall surfaoe, and intended to function essentially as a' radiator. ' Perimeter System: See Warm Air Heating System. Permeability: Water vapor permeability is a property of a substance which permits passage of water vapor, and is equal to the permeance of a 1 in. thickness of the substance. When permeability varies with psychrometric conditions, the Spot or Specific Permeability defines the property at a specific condi tion. Permeability is measured in perm-inches. Permeance: The water vapor permeance of a sheet of any thickness (or assembly between parallel surfaces) is the ratio of water vapor flow to the .vapor pressure difference between the surfaces- Permeance is measured in perms. Perm: The unit of permeance. A perm is equal to 1 grain per (sq ft) (hr) (inch of mercury vapor pressure difference). Plenum Chamber: An air compartment maintained under pressure, and connected to one or more distributing ducts. Potentiometer: An instrument for comparing small electro motive forces, or for measuring small electromotive forces by comparison with a known electromotive force. Its principal advantage is that during the measurement, no current flows through the source of electromotive force. Power: The rate of performing work. Common units are horsepower. Btu per hour, and watts. Pressure: Force per unit area. Common units are pounds per square inch, gram per square centimeter, inch of water, millimeter of mercury. Pressure, Absolute: The sum of the gage pressure aod the barometric pressure. Pressure, Dynamic: Same as Total Pressure. Pressure, Gage: Pressure measured from atmospheric pressure as a base. Gage pressure may be indicated by a msnometer which has one leg connected to the pressure source 'and the other exposed to atmospheric pressure. Pressure, Saturation: The saturation pressure for a pure substance for any given temperature is that pressure at which ' vapor and liquid, or vapor and solid, can coexist in stable equilibrium. Pressure, Static: The normal force per unit area that would be exerted by a moving fluid on a email body immersed in it if the body were carried along with the fluid. Practically, it is the normal force per unit area at a small hole in a wall of the duct through which the fluid flows (piezometer) or on the surface of a stationary tube at a point where the disturbances, created by inserting the tube, cancel. It is supposed that the thermodynamic properties of a moving fluid depend od static pressure in exactly the same manner as those of the same fluid . at rest depend upon its uniform hydrostatic pressure. Pressure,-Total: In the theory of the flow of fluids; the sum of the static pressure and the velocity pressure at the point of measurement. . Pressure, Vapor: The pressure exerted by a vapor. If a vapor is kept in confinement over its liquid so that the vapor can accumulate above the liquid, the temperature being held constant, the vapor pressure approaches a fixed limit called the maximum, or saturated, vapor pressure, dependent only on the temperature and the liquid. The term vapor pressure is sometimes used as synonymous with saturated vapor pressure. Pressure, Velocity: In a moving fluid, the pressure capable of causing an equivalent velocity, if applied to move the same fluid through an orifice such that all pressure energy expended is converted into kinetic energy. Psychrometer: An instrument for ascertaining the humidity or hygrometric state of the atmosphere. 'Psychrometric: Pertaining to psychrometry or the state of the atmosphere with reference to moisture. Psychrometric Chart: A graphical representation of the thermodynamic properties of moist air. Psychrometry: The branch of physics relating to the mens- urement or determination of atmospheric conditions, particu larly regarding the moisture mixed with the air. Pyrometer: An instrument for measuring high temperatures. Radiant Heating: A beating system in which only the beat radiated from panels is effective in providing the heating requirements. The term Radiant Heating is frequently used to include both Panel and Radiant Heating. Radiation: The transmission of energy by means of electro magnetic waves'. Radiation, Thermal (Heat) Radiation: The transmission of energy by means of electromagnetic waves of very long wave- length. Radiant energy of any wavelength may, when ab sorbed, become thermal energy and result in an increase in the temperature of the absorbing body. \ Radiation, Equivalent Direct (EDR): A unit of heat delivery of 240 Btu per hr. It does not imply 144 sq in. of surface. Radiator: A heating unit exposed to view within the room or space to be heated. A radiator transfers heat by radiation to ooiects within visible range, and by conduction to the sur rounding air which in turn is circulated by natural convection; a so-called radiator is also a convector, but the term radiator has been established'by long usage. Radiator. Concealed: A heating device located within, adjacent to, or exterior to the room being heated, but so covered or enclosed or concealed that the heat transfer surface of the device, which may be either a radiator or a convector, is not ' . J ij <; , i ; ' j -j { J : : ; ' ' , ; : : '. \ . . Terminology visible from the room. Such a device transfers its heat to the room largely by convection air currents. Radiator, Direct: Same as Radiator. Radiator, Recessed: A heating unit set back into a wall recess, but not enclosed. Radiator, Tube or Tubular: A heating unit used as a radia tor in which the heat transfer surfaces are principally tubes. Refrigerant: A substance which produces a refrigerating effect by its absorption of heat while expanding or vaporising. Refrigeration, Ton of: The removal of heat at a rate of 200 Btu per min, 12,000 Btu per hr, or 288,000 Btu per 24 hr. Resistance, Thermal: The reciprocal of thermal conduct ance. Symbol R. Resistivity, Thermal: The reciprocal of thermal conduc tivity. Symbol r. Resistor, Electric: A material used to produce heat by pass ing an electric current through it. Return, Dry: A return pipe in a steam heating system which carries both water of condensation and air. The ary return is above the level of the water line in the boiler in a gravity sys tem. (See Return, Wet.) Return, Wet: That part of a return main of a steam heating system which is fillca with water of condensation. The wet return usually is below the level of the water line in the boiler, although not necessarily so. (Sec Return, Dry.) Return Mains: Pipes or conduits which return the heating or cooling medium from the heat transfer unit to the source of heat or refrigeration. Reversed-Return System: A system in which the heating or cooling medium from several heat transfer units is returned along paths arranged so that all circuits composing the system or composing a major sub-division of it are of practically equal length. Sabin: A unit of equivalent sound absorption equal to the equivalent absorption of one square foot ot a surface of unit absorptivity (i.e., of one square foot of surface which absorbs all incident sound energy). ' Saturation: The condition for co-existence in stable equi librium of a vapor and liquid or a vapor and solid phase of the same substance. Example: Steam over the water from which it is being generated. Saturation, Degree of: The ratio of the weight of water vapor associated with a pound of dry air to the weight of water vapor associated with a pound of dry air saturated at the same temperature. .- Smoke: An air suspension (aerosol) of particles, usually but not necessarily solid, often originating in a solid nucleus, formed from combustion or sublimation. Also defined as carbon or soot particles less than 0.1 micron in size which result from the incomplete combustion of carbonaceous materials such as coal, oil, tar, and tobacco. Smokeless Arch: An inverted baffle placed in an up-draft furnace toward the rear to aid in mixing the gases of combus tion, and thereby to reduce the smoke produced. Solar Constant: The solar intensity incident on a normal surface located outside the earth's atmosphere at a distance from the sun equal to the mean distance between the earth and the sun. Its value is 415, 445, or 430 Btu per (hr) (sq ft) as the July, January, or mean value, respectively. At sea level in July the solar intensity value is about 300 Btu per (sq ft) (hr) since about 28 percent is absorbed in the eartn's atmos phere. Sorbent: A material which extracts one or more substances present in an atmosphere or mixture of gases or liquids with which it is in contact, due to an affinity for such substances. Sorption: Adsorption or absorption. Split System: A system in which the heating is accomplished by means of radiators or convectors supplemented by mech anical circulation of air (heated or unheated) from a central point. Ventilation may be provided by the same system. Square Foot of Heating Surface (Equivalent): This term is synonymous with Equivalent Direct Radiation (EDR). Stack Height: The height of a gravity convector between the bottom of the heating unit and the top of the outlet open ing. 5 Steam: Water in the vapor phase. Dry Saturated Steam is steam at the saturation temperature corresponding to the ressure, and containing no water in suspension. Wet Saturated Steam is steam at the saturation temperature corresponding to the pressure, and containing water particles in suspension. Superheated Steam is steam at a temperature higher than the saturation temperature corresponding to the pressure. Steam Heating System: A heating system in which heat is transferred from the boiler or other source of heat to the heat ing units by means of steam at, above, or below atmospheric pressure. Steam Trap: A device for allowing the passage of condensate, or air and condensate, and preventing the passage of steam. Supply Mains: The pipes through which the heating medium flows from the boiler or source ot supply to the run-outs and risers leading to the heating units. Surface, Heating: The exterior surface of a heating unit: Extended Heating Surface (or Extended Surface): Heating surface consisting of fins, pins, or ribs which receive heat by conduction from the prime surface. Prime Surface: Heating surface having the heating medium on one side and air (or extended surface) on the other. (See also Boiler Healing Surface.) Temperature: The thermal state of matter with reference to its tendency to communicate heat to matter in contact with it. If no heat flows upon contact, there is no difference in temperature. Temperature, Absolute: Temperature expressed in degrees above absolute zero. - Temperature, Dew-Point: The temperature at which the condensation of water vapor in a space begins for a given state of humidity and pressure as the temperature of the vapor is reduced. The temperature corresponding to saturation (100 percent relative humidity) for a given absolute humidity at constant pressure. Temperature, Dry-Bulb: The temperature of a gas or mix ture of gases indicated by an accurate thermometer after cor rection for radiation. Temperature, Effective: An arbitrary index which combines into a single value the effect of temperature, humidity, and air movement on the sensation of warmth or cold felt by the human body. The numerical value is that of the temperature of still, saturated air which would induce an identical sensa tion. Temperature, Mean Radiant (MRT): The temperature of a uniform black enclosure in which a solid body or occupant would exchange the same amount of radiant heat as in the ex isting non-uniform environment. Temperature Scales: Three temperature scales, Centigrade, Fahrenheit, and Reaumur, derive their degree values by divid ing the difference between the ice point and steam points o! water as follows: Centigrade 100, Fahrenheit 180, and Reaumur 80. Only the first two are important in the United States. The value of a Fahrenheit degree is therefore 5/9 of a Centigrade degree. - The Kelvin scale, sometimes called Centigrade absolute, has its zero point at the lowest attainable temperature 273.16 Centigrade degrees below the triple-point temperature of water and exactly 273.15 below the zero of the Centigrade scale. The Rankine scale, sometimes called Fahrenheit absolute, has its zero at the lowest attainable temperature 459.688 Fahrenheit degrees below the triple-point temperature of water and exactly 459.67 F deg below the zero of the Fahrenheit scale. To convert Centigrade to Kelvin temperature (generally s' designated K) add 273.15 deg. . To convert Fahrenheit to Rankine temperature (generally . designated R) add 459.67 deg. - Temperature, Wet-Bulb: Thermodynamic wet-bulb temper ature is the temperature at which liquid or solid water, by evaporating into sir, can bring the air to saturation adiabatically at the same temperature. Wet-bulb temperature (without qualification) is the temperature indicated by a wet-bulb psychrometer constructed and used according to specifications. (ASME Power Test Codes, Series 1932, Instruments and Apparatus, Part 18.) Therm: A quantity of heat equivalent to 100,000 Btu. 6 CHAPTER 1 1959 Guide Thermodynamics, Laws of: Two laws upon which rest the classical theory of thermodynamics. These laws have been stated in many different, but equivalent ways. The First Law: (1) When work is expended in generating heat, the quantity of beat produced is proportional to the work expended; and conversely, when heat is employed in the performance of work, the quantity of heat which disappears is proportional to the work done. (Joule)**(*G.P.)b; (2) If a system is caused to change from an initial state to a final state by adiabatic means only, the work done is the same for ail adiabatic paths connecting the two states. (Zemansky); (3) In any power cycle or refrig eration cycle the net beat absorbed by the working substance is exactly equal to the net work done. The Second Law: (1) It is impossible for a self-acting machine, unaided by any ex ternal agency, to convey heat from a body of lower to one of higher temperature. (Clausius) (G.P.); (2) It is impossible to derive mechanical work from heat taken from a body unless there is available a body of lower temperature into which the residue not so used may be discharged. (Kelvin) (G.P.); (3) It is impossible to construct an engine that, operating in a cycle, will produce no effect other than the extraction of heat from a reservoir and the performance of an equivalent amount of work (Zemansky). Thermostat: An instrument which responds to changes in temperature, and which directly or indirectly controls tem perature. Transmittance, Thermal: The time rate of heat flow, from the fluid on the warm side to the fluid on the cold side, per (square foot) (degree temperature difference between the two fluids). Sometimes called Overall Coefficient of Heat Transfer. Common unit is Btu per (hour) (square foot) (Fahrenheit degree). Symbol U. Two-Pipe System (Steam or Water)'. A heating system in which one pipe is used for the supply of the heating medium to the heating unit, and another for the return of the heating medium to the source of heat supply. The essential feature of a two-pipe system is that each heating unit receives a direct supply of the heating medium, which medium cannot have served a preceding heating unit. Up-Feed System: A heating system in which the supply mains are. below the level of the heating units which they serve. Vacuum Heating System: A two-pipe steam heating system equipped with the necessary accessory apparatus which will permit operating the system below atmospheric pressure when desired. Vane Ratio: In air distributing devices the ratio of depth of vane to shortest opening width between two adjacent grille bars. Vapor: The gaseous form of substances which are normally in the solid or liquid state, and which can be changed to these states either by increasing the pressure or decreasing the temperature. Vapors diffuse. (ASA definition.) Vapor Heating System: A steam heating system which oper ates under pressures at or near atmospheric and which returns the condensate to the boiler or receiver by gravity. Vapor * Name* of author* who first ttated ltwa an gives is parentheses. b Prom Glossary / Pkjtict, by LeRoy Dougtarty Weld (McGraw-Hill, 1337). systems have thermostatic traps or other means of resistance on the return ends of the heating units for preventing steam from entering the return mains; they also nave a pressure equalizing and air-eliminating device at the end of the dryreturn. Velocity: A vector quantity which denotes at once the time rate and the direction of a linear motion. V -- t*. For uniform linear motion V -- Common units are: feet per second. Ventilation: The process of supplying or removing air, by natural or mechanical means, to or from any space. Such air may or may not have been conditioned. (See Air Conditioning.) Viscosity: That property of semi-fluids, fluids, and gases by virtue of which they resist an instantaneous change of shape or arrangement of parts. It is the cause of fluid friction whenever adjacent layers of fluid move with relation to each other. The coefficient of viscosity is the resistance offered by a layer of the fluid of unit area to the motion parallel to this area of another layer of the fluid at unit distance moving with unit velocity relative to the first layer. This coefficient is knowD as the absolute viscosity, and in cgs units is the force in dynes per square centimeter at a velocity of 1 cm per second at a distance of 1 cm. This unit of absolute viscosity is the poise. Values of absolute viscosity are frequently listed in centipoises, a centi- poise being 1/100 of'l poise. In many formulas absolute viscosity is expressed in pounds per foot second or pounds per foot hour. Conversion from centipoises may be made as follows: viscosity in centipoises X 0.000672 - viscosity in.pounds per foot second, or viscosity in centipoises X 2.42 = viscosity id pounds per foot hour. Kinematic viscosity is the ratio of absolute viscosity to the density of a fluid. The unit is the stoke which equals one poise sr cu cm per gram, or 1 sq cm per sec. For conversion to gnglish units: kinematic viscosity in stokes X 0.001076 = kinematic viscosity in square feet per second. Volume, Specific: The volume of a substance per unit mass; the reciprocal of density. Units: cubic feet per pound, cubic centimeters per gram, etc. - Warm Air Heating System: A warm air heating plant con sists of a heating unit (fuel-burning furnace) enclosed in a casing, from which the heated air is distributed to various rooms of the building through ducts. Warm Air Heating System, Forced: A warm air heating system in which circulation of air is effected by a fan. Such a system may include air cleaning devices. Warm Air Heating System, Gravity: A warm air heating system in which the motive head producing flow depends on the difference in weight between the heated air leaving the casing and the cooler air entering the bottom of the casing. Warm Air Heating System, Perimeter: A warm air heating system of the combination panel and convection type. Warm air ducts embedded in the concrete slab of a basementless house, around the perimeter, received heated air from a fur nace and deliver it to the heated space through registers placed in or near the floor. Air is returned to the furnace from registers near the ceiling. A a Alpha B & Beta r 7 Gamma A b Delta Et Epsilon z S Zeta THE GREEK ALPHABET H, Eta 0i? Theta I i lota K x Kappa AX Lambda M fi Mu Nv 2{ 0o nv pp S as Nu Xi Omicron Pi Rho Sigma Tr Tu 4> <p 4> Xx *f Q a) Tau Upsilon Phi Chi Psi Omega CHAPTER 2 ABBREVIATIONS, SYMBOLS, CONVERSION FACTORS Standard Abbreviations,- Standard Symbols; Conversion Equations; Graphical Symbols for Piping, Ductwork, Heating and Ventilating, Refrigerating; Wenfificofion of Piping by Color THIS chapter contains information regarding abbrevia tions, symbols, and conversion equations, which arc of Foot-pound-second (system) Freezing point.......................... Gallon.......................................... particular interest to the engineer engaged in heating, venti Gallons per minute................ :X -gal gpm lating, and air conditioning. ` Gallons per second........................................................................... gps ABBREVIATIONS Gram.....................................................'................................................. K Gram-calorie................................................................................. -g*cal Abbreviations are shortened forms of names and expressions employed in texts and tabulations, and should not generally Horsepower........................................................................................... hp Horsepower-hour...........................................................................hp-hr be used as symbols in equations. Most of the following ab breviations have been compiled from a list of approved stand ards.1 In general, the period h< been omitted in all abbrevia tions, except where the omission results in the formation of an English word. Hour........................................................................................................ hr Inch.................................................................................................... -in. inch-pound..................................................................................... in -/lb Indicated horsepower................................................................. - .ihp Indicated horsepower-hour.......................................................ihp-hr Absolute........................................................................................... abs Air horsepower............................................................................air hp Alternating-current (as adjective).............................................. a-c Ampere............................................................................................... amp Ampere-hour...............................................................................amp-hr Kilogram.......... Kilowatt......... Kilowatt-hour Mass................. Melting point. ...kg .. .kw kwhr .mass . .rap Atmosphere.......................................................................... atm Average..............,...............................................................................avg Avoirdupois. ...................................................................................avdp Barometer..........................................................................................bar. Boiling point........................................................................................bp Brake horsepower............................................................................ bhp Brake horsepower-hour............................................................ bhp-hr British thermal unit......................................................................Btu British thermal units per hour.................................................Btuh Calorie................................................................................................. .cal Meter........................................................................................................tn Micron........................................................................................... ft (mu) Miles per hour................................................................................. mPb Millimeter........................................................................................... m.m Minute..................... ..........................................................................min Molecular weight........... Mol...................................... Ounce.................................. Pound................................ Founds per square inch .mol wt ___ mol ........ os ..........lb ........psi Centigram............................................................................................. eg Centimeter................................................................................ - . cm Centiraeter-gram-second (system).............. /.............................cgs Cubic............................................ ,,.....................................................cu Cubic centimeter................... '.'T.................................... cu cm or cc Pounds per square inch, gage..................................................... psig Pounds per square inch, absolute.............................................. psia Revolutions per minute.................................................................rpra Revolutions per second................................................................... rps Second................................................................................................... *c Cubic foot...................................................................................... cu ft Cubic feet per minute.................................................................... cfm Cubic feet per second...................................................................... cfs Decibel.................................................................................................. db Degree*.......................................................................................deg or * Degree, Centigrade............................................................................. C Degree, Fahrenheit..............................................................................F Degree, Kelvia...................................................................... ?........... K Degree, Rankine.................................... R Diameter..............................................................................................dia Direct-current (as adjective)........................................................ d-c Electromotive Force....................................................................... emf Feet per minute............................................................................... fpm Feet per second................... fps Foot.......................................................................................................... ft Foot-pound.................................................................................... ft-lb 1 Abbrariitiwii for Scientific and Engineering Term*. ZiO.1-1341 (American Standards Association). . It is recommended that the abbreviation for the temperature scale, F, C. K, R, be included in expressions for numerical temperatures but, wherever feasible, the abbreviation for ittrt* be omitted c-y., (8 F. ' Specific gravity........ :......................................................................... 8PKr Specific heat..........................................................................................SPht Square foot........................................................................................... sqft Square inch....................................................................................sq *QWatt....:........................................................................................... .... W Watthour.......................... .............................................................. wbr SYMBOLS A letter symbol is a single character, with subscript or superscript if required, used to designate a physical magnitude in mathematical equations and expressions. Two or more sym bols together always represent a product. The following have been compiled from a selected list of approved standards.* Additional symbols and variations in the standard symbols found necessary in the individual chapters will be found in a list at the end of Chapters 3, 4, 13, and 53. y^- Acceleration, due to gravity............................................................ 9 Acceleration, linear..............................................................................a * t ***** Symbols for MM TfcvTiv*, Z10A-1MS, and Letter Symbols for Hei god Thermodynamics, Y10.4-1957 (American Standard* Association). 7 8 CHAPTER 2 1959 Guide Area.......................................... ...................................................... A Change in specific volume during vaporisation...................... >v# Density, Weight per unit volume, Specific weight, .d or p (rho) Distance, linear..........................-................................. -...................... s Dry saturated vapor, Dry saturated gas at saturation pres sure and temperature, vapor in contact with liquid ........................................................................................ Subscript g Efficiency............................................................................................... . Elevation above some datum.................................................... s Emissivity...................................................................... 'j Energy in general; work, total; work, moial. . . . . . . . . . . . . ..E Entropy. (The capital should be used for any weight, and the small letter for unit weight)........................... ....... S or s Force, total load..............................................................................F Gas Constant, in equation pK - nRT............ ..........................R Head............................................................................................. H or h Heat content, Total heat, Enthalpy. (The capital should be used for any weight and tne small letter for unit weight)..................................................................................H or h Heat content of saturated liquid. Total heat of saturated liquid, Enthalpy of saturated liquid, sometimes colled heat of the liquid....................................................................... h} Heat content of dry saturated vapor, Total heat of dry sat urated vapor, Enthalpy of dry saturated vapor.................. ht Heat of vaporization at constant pressure.................... L or h/t Hydraulic radius...............................................................................R w Internal energy, Intrinsic energy. (The capital should be used for any weight and the small letter for unit weight).................................................................................. .... or u Length of path of heat flow, thickness..................................:. .L Load, total......................................................................................... .W Mechanical efficiency............................................................ e Mechanical equivalent of heat.................................... j Power, Horsepower, Work per unit time. ............ . .P Pressure, Absolute pressure. Gage pressure, Force per unit area.................................................................................................. ... Quantity (total) of fluid, water, gas, heat; Quantity by volume; Total quantity of heat transferred....................... Q Quality of steam. Pounds of dry steam per pound of mix ture ........................................................................................ x Reynolds Number....................................................................\ ' 'ff'B Saturated'liquid at saturation pressure andtemperature * Liquid in contact with vapor............................ . Subscript f Specific heat.................................................................................... c Specific heat at constant pressure................................................ * Specific heat at constant volume...................;................... .... .c Specific volume, Volume per unit weight, Voiume per unit * Temperature (ordinary) F or C. (Theta is used preferabiy " only when t is used for Time in the same discussion) ...................................................................................... . or 6 (theta) Temperature (absolute) F abs or K. (Capital theta is used preferably only when small theta is used for ordinary temperature) .-.........................................T or (capital theta) Thermal conductance :4 heat transferred per (unit time) (degree)........................................................................................... ... C=- -g R . L I, - t, Thermal conductance per unit area, Unit conductance: heat transferred per (unit time) (unit area) (degree) C- C *A 1 * RA " A(tt - tO = L Thermal conductivity: heat transferred per (unit time) (unit area) (degree per unit length)......................................k i_ . .A * " (h - <*) L Surface coefficient of heat transfer, Film coefficient of heat transfer, Individual coefficient of heat transfer: heat transferred per (unit time) (unit area) (degree)........ / (In general / is not equal to k/L, where L is the actual thick ness of the fluid film.) Overall coefficient of heat transfer, Thermal transmittance per unit area: heat transferred per (unit time) (unit area) (degree overall)................................................................. y q Thermal transmission (heat transferred per unit time).......... q Q -7 Thermal resistance (degree per unit of heat transferred per unit time)................................................................................R q kA Thermal resistivity........................................................................... i/fc Vaporization values at constant pressure, Differences be tween values for saturated vapor and saturated liq uid at the same pressure....................................... Subscript/g Velocity................................................................................................. y Viscosity, absolute..................................................... Viscosity, kinematic.......................................................... .... p ' "u'/a Volume (total)........;......................................................... ................ y Volume per unit time, Rate at which quantity of materiai passes through a machine, Quantity of heat per unit time, Quantity of heat per unitweight.................................q Weight of a major item, Total weight.............................. W Weight rate, Weight per unit of power, Weight per unit time of.............. w Work (total)..................................................................... . . . . . . . . . W CONVERSION EQUATIONS' Heof, Power and Work 1 ton refrigeration Latent heat of ice 1 Btu / P^. hour \ 200 Btu per minute 143.4 Btu per pound f 778.3 ft-lb ( 0.2930 Int. whr ( 252.0 I.T. calorie 1 Int- watthour [ 2656 ft-lb J 3.413 Btu 1 3600 Int. joules l 860 I.T. calories . 1 Int. kilowatthour f 3,413 Btu = < 3.517 lb water evaporated ( from and at 212 F * Checked in 1M4 by Nations! Bureau of Standard*. Abbreviation ha. and I.T. refer to International and International (Steam) Table, respectively. Abbreviations, Symbols, Conversion Factors 1 Int. kilowatt (1000 watts) f 1.341 hp - \ 56.88 Btu per minute { 44,267 ft-lb per minute 10QO.I.T. calories! 1 I.T. kilocalorie/ 1 3088*ft-lb l 1.1628 Int. whr 1 horsepower 1 boiler horsepower 0.7455 Int. kw ! 42.40 Btu per minute 33,000 ft-lb per minute 550 ft-lb per second / 33,475 Btu per hour \ 9.809 lot. kw Weight and Volume 1 gal (U. S.) . / 231 cu in. \ 0.1337 cu ft 1 British or Imperial gallon 277.42 cu in. 1 cu ft 7.481 gal 1728 cu in. 1 cu ft,water at 60 F (in vacuo) 62.37 lb leu ft water at 212 F(" u ) * 59.83 lb 1 gal water at 60 F (" " ) = 8.338lb 1 gal water at 212 F (" " ) = 7.998lb 1 lb (avdp) 16 02 7000 grains. 1 bushel 1 short too 1.244 cu ft 2000 lb Pressure 1 lb per square inch 144 lb per square foot 2.0360 m. mercury at 32 F > 2.0422 in. mercury at 62 F 2.309 ft water at 62 F 27.71 in. water at 62 F 1 oz per square inch 0.1276 in. mercury at 62 F 1.732 in. water at 62 F 1 atmosphere 14.696 lb per square inch 2116 lb per square -foot = 33.94 ft water at 62 F 30.01 in. mercury at 62 F 29.921 in. mercury at 32 F 1 in. water at 62 F (in vacuo) 1 ft water at 62 F (in vacuo) 0.03609 lb per square inch 1 0.5774 oz per square inch 5.197 lb per square foot 0.4330 lb per square inch 62.37 lb per square foot 0.4897 lb per square inch 11 in. mercury at 62 F (in vacuo) = 7.835 oz per square inch 1.131 ft water at 62 F 13.57 in. water at 02 F 1 in. mercury at 32 F (in vacuo) = 0.49115 lb per square inch Metric Units 1 cm 1 in. 1m 1 ft 1 sq cm 1 sq in.. . 1 sq m 1 sq ft 1 cu cm 1 cu in. 1 cu m - -- 0.3937 in. = 0.0328 ft = 2.540 cm = 3.281 ft = 0.3048 m = 0.1550 sq in. -- 6.452 sq cm -- 10.76 sq ft = 0.09290 sq m -- 0.06102 cu in. : = 16.39 cu cm " 35.31 cu ft 9 1 cu ft 1 liter 1 kg 1 lb 1 metric ton 1 gram 1 kilometer per hour 0.02832 cun ' . 1000 cu cm * 0.2642 gal 2.205 lb (avdp) 0.4536 kg ' 2205 lb (avdp) - 0.002205 lb (avdp) . 0.6214 mpb -. 1 gram per square centimeter 0.02905 in. mercury at 62 F 0.3942 in. water at 62 F 1 kg per sq cm (metric at mosphere) = 14.22 ib per square inch 1 gram per cubic centimeter / 0.03613 lb per cubic inch \ 62.43 lb per cubic foot 1 dyne = 0.00007233 poundals 1 absolute joule / 10,000,000 ergs \ 0.7376 ft-lb 1 Int. joule = 0.7378 ft-lb , metric honker -{ ^ 1 I.T. kilocalorie per kilogram = 1.8 Btu per pound I Im.Te.tecralorie per square centi- " 3*.6e8m7 Btu per square ,foo*t 1 I.T. calorie per (second) (square centimeter) for a temperature gradient of 1 C deg per centimeter 2903 Btu per (hour) (square foot) for a tem perature gradieht of I F deg per-inch of thick ness. - GRAPHICAL SYMBOLS FOR DRAWINGS* Piping Heeling 1. High-Pressure Steam 2. Medium-Pressure Steam 3: Low-Pressufe Steam 4. High-Pressure Return 5. Medium-Pressure Return '6. Low-Pressure-Return 7. Boiler Blow Off 8. Condensate'or. Vacuum. Pump Discharge 9. Feedwater. Pump Discharge 10. Make-Up Water ' 11. Air Relief Line 12. Fuel Oil Flow 13. Fuel Oil Return 14. Fuel Oii Tank Vent 15. Compressed Air 10. Hot Water Heating Supply 17. Hot Water Heating Return Air Conditioning 18. Refrigerant Discharge 19. Refrigerant Suction 20. Condenser Water Flow 21. Condenser Water Return 22. Circulating-Chilled or Hot Water JPlow -------------- ch--------------- * Extracted from: American Standard Graphical Symbol* for Pipe Fittings Valves; "<* Piping (ASA Z22.2.J-I9W) and Anerian Standard Graphical Sym bols for Heating. Ventilating, and Air Conditioning (.ASA Z32.2.+-1W9) with the permission of the publisher. The American Society of Mechanical Engineer*, 29 West 59th St.. New York 18. N. Y. ' 10 23. Circulating Chiliad or Hot Water Return 24. Make-Up Water 25. Humidiflcation Line 28. Drain 27. Brine Supply 28. Brine Return Phtmbtng 29. Soil, Waste, or Leader (Above Grade) 30. Soil, Waste, or Leader (Belov Grade) 31. Vent 32. Cold Water 33. Hot Water 34. Hot Water Return 35. Fire Line 36. Gas 37. Acid Waste 38. Drinking Water Flow 39. Drinking Water Return 40. Vacuum Cleaning 41. Compressed Air Sprmfcfvn 42. Main Supplies 43. Branch and Head 44. Drain ACIO CHAPTER 2 12. Traps 12.1 Boiler Return 12.2 Blast Thermo- static 12.3 Float 12.4 Float and Ther mostatic 12.5 Thermostatic 13. Unit Heater (Centrifugal Fan), Plan 14. Unit Heater (Pro peller), Plan 15. Unit Ventilator, Plan 16. Valves' 16.1 Check 16.2 Diaphragm 16.3 Gate 16.4 Globe 1959 Guide 5< => -GU- ------ ------ | i\i ill g5~| cSb -do- Heating 1. Air Eliminator 2. Anchor 3. Expansion Joint 4. Hanger or Support 5. Heat Exchanger 6. Heat Transfer Sur face, Plan (Indi cate Type Such as convector) 7. Pump (Indicate Type Such as Vacuum) 8. Strainer 9. Tank (Designate Type) 10. Thermometer 11. Thermostat PA o 6 6-- = -- I______ ) 0-a I"EC| 16-5 Lock and Shield 16.6 Motor Operated 16.7 Reducing Pres sure 10.8 Relief (Either Pressure or Vacuum) 17. Vent Point Ventilating 18. Access Door -do 3 19. Adjustable Blank Off 20. Adjustable Plaque r TR 20X12 i P-2oxi2-7oocrm d; -? yp-20-4* Abbreviations, Symbols, Conversion Factors Ventilating 21. Automatic Dampers 22. Canvas Connections 23. Deflecting Damper 24. Direction of Flow 25. Duct (1st Figure. Side Shown: 2nd Side Not Shown) 26. Duct Section (Ex , hailst or Return) 27.'Duct Section (Sup ply) 28. Exhaust Inlet Ceiling (Indicate Type) 29. Exhaust Inlet Walt (Indicate Type) 30. Fan and Motor With Belt Guard 12X20 i OR R 20X 12) 20X12) w^-wCR 20 X 12 - 700 Cfm If--ncg 20 x rz - 700 Cfm n- TR-I2*8 70ocf m ^3 31. Inclined Drop in Re- T ' ' IH1 -- lilf 4 mispect to Air Flow_________ ._____________ 32. Inclined Rise in Re- *=& spect to Air Flow 33. Intake Louvers on Screen 1 35. Supply Outlet Ceil- L 20)^12-700 Cjm I- Q 20'O'AM. 1000 Cfm ing (IndicateType) 36. Supply Outlet Wall (Indicate Type) TR - 12X6 700 Cfm 37. Vanes 38. Volume Damper Air Conditioning 39. Capillary Tube 40- Compressor 41. Compressor, En closed, Crankcase, Rotary, Belted 42. Compressor, Open Crankcase, Recip rocating, Belted 43. Compressor, Open Crankcase, Recip rocating, Direct Drive 44. Condenser, Air Cooled, Finned, Forced Air 45. Condenser, Air Cooled, Finned, Static - 46. Condenser, Water Cooled, Concentric Tube in a Tube 47. Condenser, Water Cooled, Shell and Coil 48. Condenser, Water Cooled, Shell and Tube . 49. Condensing Unit, Air . Cooled 50. Condensing Unit, Water Cooled 51. Cooling Tower ' 52. Dryer 53. Evaporative Con denser 54. Evaporator, Circu lar, Ceiling Type, Finned 55. Evaporator, Mani folded, Bare Tube, Gravity Air _ 56. Evaporator Mani folded, Finned, Forced Air 57. Evaporator Mani folded, Finned, Gravity Air 58. Evaporator, Plate Coils, Headered or Manifold 59. Filter, Line 60. Filter and Strainer, Line 61. Finned Type Cooling Unit, Natural Con vection 62. Forced Convection Cooling Unit -----AAAA/V-- 8 -IIHHi It 1 11 I U Hill*1 ~S~1 /S /\ u 12 63. Gage --64. High Ssde'Float \ '65. Immersion iCooimK Unit 66. Low Side Float 67. Motor-Compressor, Enclosed Crank case, Reciprocat ing, ;iDirect CodHeci^d 68. Motor-Compressor, Enclosed -Crank case, Rotary, Di rect Connected '69. Motor-Compressor, Seated uffifikease. Reciprocating 70. Motor-Compressor, Sealed Crankcase, Rotary'-'' - ' 71. Pressurestat 72. Pressure Switch 73. Pressure Switch With High Pressure Cut . Out .. 74. Receiver; Horizontal 75. Receive^Vertical 76. Scale Trap 77. Spray Pond - 78. Thermal-^ulb `79. Thermostat (Remote Bulb) u 80. Valves . < :80.1 Automatic Expan sion 80.2 Compressor Suction Pressure Limiting, Throttling-Type (Compressor Side) 80.3 Constant Pressure, Suction 80.4 Evaporator Pres sure Regulating, Snap Action. . '80.5 Evaporator Pres sure Regulating, Therinostatio Throttling Type 80.6 Evaporator' Pres sure Regulating, Throttling . Type (Evaporator Side) 2 X a CHAPTER 2 80.7 Hand Expansion 80.8 Magnetic Stop 80.9 Snap Action' 1959 Guide <> : i cH)-' ; m> ' , '&> AAA--(p)--WV-- -dEb -rFhr-n \~dQr\r~\l 80.10 Suction. Vapor Regulating 80.11 Thermo Suction 8U.12Thermastatic Ex-' . .. _ pansion 80.13 Water Vibration Absorber, Line' " . <$- -M- IDENTIFICATION OF PIPING SYSTEMS BY COLOR The color scheme for identification of piping systems, based on material carried, as listed in the following table and shown m Kg. 1, is reprinted from Part V, Fourth Edition, of the Engineering Standards of the Heating, Piping and Air Con ditioning Contractors National Association.' ' Class -. F--Fire-protection - D--Dangerous materials 8--Safe materials . Color Red Yellow or Orange Green (or the achromatic col ors, white, black, gray or aluminum) and, when required * P--Protective materials Bright blue V--Extra valuable materials Deep purple --(1 -<5=- ds Association. ' PC? CHAPTER 3 . THERMODYNAMICS Mass' and Energy Balances, Thermodynamic Properties of Moist Air, Formulas and Tables; Thermodynamic Properties of Water, Formulas and Tables; Degree of Saturation; ASHAE PSYCHJOMfTMC CHART; Solution of Air Conditioning * Problems by Use of Tables arid Prychromefric Chart; U. S. Standard Atmospheres. -. ,!{ .. HERMODYNAMICS is that branch of natural science where ' Twhich deals with energy and its transformations into various forms. In tins chapter the discussion will be limited PE = potential energy, Btu per-pound dry air. to thermodynamics as it affects the arts of heating and air KE = kinetic energy, Btu per pound dry air. conditioning. This will necessarily presume some knowledge - H =* enthalpy, Btu per pound dry air. ' of the fundamentals of the science on the part of the reader -- heat added between sections 1 and 2, Btu per pound who may also find it desirable to refer to a standard text dry air. ' on the subject, preferably one published after 1930. . w = shaft work withdrawn between sections 1 aod 2, Btu per pound of dry air. MASS AND ENERGY BALANCES The First Law of Thermodynamics is a statement of the For most psychrometric problems, since the change in the potential energy, and kinetic energy terms is negligible com Principle of Conservation of Energy. It may be stated as follows: The energy added to a system is equal to the increase pared to the enthalpy change. Equation 3 may be written or decrease of the energy stored in the system, plus the energy Hi + iq* = Hi + w (4) which leaves the system. Fora completely contained, or nonflow system, this, may be restated, as: The heat added to a non where ' flow system is equal to the change in the internal energy of the system, plus the work done by the system. H -- enthalpy of flowing medium, Btu per pound of dry air. ,q, = U,-U, + w For a constant pressure process (1) The enthalpy of the entire system may be broken down into constituent parts, thus: ' ' . ' jq* ** Hi -- H* ' (2) GH * Gh + Lfc.1 + SK, ' (5) where - where' ' `` .j tq -- energy added between points 1 and 2. U = internal energy of system. ' w = work done by system.' ' H = enthalpy of system. - Subscripts 1 and 2 refer to sections of the system between which a change takes place. ' h enthalpy of moist air'Btu per pound of dry air.- hmi -- enthalpy of liquid water, Btu per pound. k*. -- enthalpy of solid water, Btu per pound. L = flow rate of liquid water, pounds per hour. ' S = flow rate of solid water,, pounds per hour. G -- flow rate of-dry air, pounds per hour. For engineering problems, a more important application of the First Law is its use in cases in which, in addition to energy,' one or more fluids are crossing the boundaries of the system. The most simple of these is the steady flow system, in which the rates of energy and mass flow across the bound aries of the system are constant, and no mass or energy is stored or released by the system. Consider a system as illustrated in -Fig. 1. The fluid cross ing the boundaries of the system carries with it potential energy by reason of its elevation above some', convenient datum, kinetic energy by reason of its velocity,: and energy in tiie form of enthalpy. Additional energy may cross the boundaries of-the system in .the forms of heat-or work. The various forms of energy crossing the boundaries between the sections under consideration may be equated by applying the First Law of Thermodynamics: * ' PB\ + KEi + Ht + ij* " PEt + KEt + Lf* + w (3) Similarly, an equation expressing the conservation of mass may be written thus: Z [G(l + W)+-L + SI - Z -((7(1 + W) + L + SJ- (6) where - . W = humidity ratio, pounds of water vapor per pound of dry air.' ' ' ' '' THERMODYNAMIC PROPERTIES OF MOIST AIR The working substance of the air-oonditioning engineer is .moist air. Air is actually a mixture of oxygen, nitrogen, car.bon dioxide, water'.vapojb.and. traces of other gasesi . ' The mixture consisting of the components other than water vapor is known as dry air. Its composition remains essentially constant under all conditions. In moist air the amount of . 13 14 CHAPTER 3 1959 Guide water vapor varies considerably. To allow for this variation the specific properties of moist air are developed in terms of tiie relative amounts of water vapor and dry air. Accepted air-conditioning practice is to express this in terms of the amount of water vapor per pound of dry air. . Terms frequently used in describing the condition of a mixture of air and water vapor are humidity ratio, relative humidify, degree of saturation, dry-bulb temperature, thermody namic tvet-bulb temperature, and dew-point temperature. These terms are defined in following paragraphs. Humidify Ratio. Weight of water vapor associated with unit weight of dry air, pounds of water vapor per pound of dry air. Humidity ratio has also been called specific humidify, and this term is still used in many places. Relative Humidity. Ratio of the mol fraction of water vapor in the actual mixture to the mol fraction of water vapor in 9 Table 1 .... Magnitudes of ft for the Range 0 to 125 F (Standard Bororaatrjc frerture, 29.92? in. Hp) Tamp, f Twnp. F tt 0 1.0048 70 1.0045 10 1.0046 80 1.0047 20 1.0046 90 1.0048 30 1.0045 too 1.0050 40 1.0044 no 1.0053 50 1.0044 120 1.0055 eo 1.0044 125 1.0057 Nett: Tfa arifinl *ource> tires /, to seven tignifiant Spires over the temperstare range --JDS F to +202 F and over the pressure range 20 to 35 in. Hg- Thermodynamxc Wet-Bulb Temperature. The temperature at which liquid or solid water, by evaporating into air, ran bring the air to saturation adiabatically at the same tempera ture. Consider an adiabatic system as shown in Fig. 2. Unsatu rated air at the state Ai , Wi, enters the system at Section 1, and saturated air at the state h,* W,* leaves the system at Section 2. Liquid waterat the state A. ,* corresponding to the temperature of the saturated air leaving the system is sup plied. Then, since no work is done and the system is strictly adiabatic, the energy equation becomes hi + (W - Wi)hS = h' (8) Fig. 1 .... Energy Change between Two Sections of a System saturated air at the same dry-bulb temperature and baro metric pressure. . . Degree of Saturation. Ratio of the actual humidity ratio to the humidity ratio of saturated air at the same dry-bulb temperature and barometric pressure. Relative humidity and degree of saturation are related according to the identity: * [i-->/] <7> * indicates condition at thermodynamic wet-bulb tempera ture. The temperature corresponding to A* for given values of hi and Wi is called the thermodynamic wet-bulb temperature, or the temperature of adiabatic saturation. ` The temperature indicated by an ordinary wet-bulb ther mometer is affected by a number of factors not accounted for in Equation 8, and hence, may be quite different from the theoretical temperature obtained from its use. The measured wet-bulb temperature is influenced by (o) radiation from the surroundings to the wick; (b) conduction of heat along the stem of the thermometer; and (c) impact of the air on the wick or bulb of the thermometer. Arnold* has developed a theory which makes possible the calculation of the true ther modynamic wet-bulb temperature from observed data through the use of suitable corrections to be applied to the where 4 * relative humidity, expressed as a decimal. M " degree of saturation, expressed as a decimal. P " observed (or barometric) pressure of the moist air. P, ** saturation pressure of pure water at the prevailing temperature, expressed in the same unite as P. . ft * a dimensionless factor which may be regarded as ac counting for influences arising when air and water are intermixed. Magnitudes of f, have been reported by Goff and Gratch1 and by Goff.* Table 1 gives values of ft for a limited range of conditions. Dry-Bulb Temperature. The temperature indicated by any type of thermometer or thermocouple not affected by the water-vapor content of the air, or by radiation. Thermodynamics 15 readings of the wetebulb thermometer. However, unless ex treme precision is required, the observed temperature may be taken equal to the theoretical temperature for most en gineering problems, if no attempt.is made to shield the wick from radiation and the air velocity past the wick is about 1000 fpm. Dew-Point Temperature. The saturation temperature cor responding to a given combination of humidity ratio W and barometric pressure is called the dew-point temperature. It is the lowest temperature at which the given humidity ratio can exist at the corresponding barometric pressure. At this temperature condensation will first start to form when moist air is cooled. Perfect Gas Relationships Hypotheses, based on experimental observation of the physical behavior of gases, which were advanced by Boyle, Charles, Gay-Lussac, Dalton, Gibbs, Joule, Kelvin, and others, were reduced to reasonably simple mathematical expressions and came to be regarded as physical laws. How ever. as scientific knowledge increased, and as more precise methods of measurement were developed, it became apparent that these simple equations did not describe the behavior of the mixtures of actual gases and vapors accurately. The original statements have been found to be useful tools, nevertheless, in many cases. For example, the behavior of common diatomic and triatomic gases at low pressures fol lows these equations closely enough so that they may be used for some types of engineering problems. Many useful engineering works have been constructed through the use of approximations. The' degree of approximation, however, which may be tolerated in engineering design must be de cided by the engineer, based upon his study and experience in the field. Boyle's Law. One of the original observations of the physi cal behavior of gases was made by Robert Boyle who noted that, if a constant weight of gas is compressed with the tem perature .held constant, the volume V varied inversely as the absolute pressure P. Stated mathematically, py = constant (temperature constant) (9) Charles' Law. Experiments made independently by Charles and Gay-Lussac led to the formulation of what is now known as Charles' Law: If a constant weight of gas is heated or cooled at constant volume, jthe absolute pressure P varies as the absolute temperature T; if a constant weight of gas is heated or cooled at constant pressure, the volume V varies as the absolute temperature T. Stated mathematically, p -- = constant (volume constant) (10) -- = constant (pressure constant) ' (11) Boyle's Law and Charles' Law may be combined to form the equation of state for the ideal or perfect gas, PV = RT (12) where R is a constant whose value depends on the units selected for P, V, and T. Datum's Rule. Dalton stated that* each gas in a mixture occupies the total volume of.the mixture just as though the other gftgra were not present. Gibbs later expanded this state ment for perfect gases into the following principles: 1. The pressure of a mixture of gases is the sum of the partial pressures of the individual gases when they exist at the total volume and temperature of the mixture. 2, The internal energy, enthalpy, and entropy of a mixture of gases are respectively equal to the sums of the individual internal energies, enthalpies, and entropies of the components when they exist at the total volume and temperature of the mixture- While thra* relationships do not hold exactly for all sys tems of real gases, they may be used with a good degree of precision for many engineering applications at low pressures. Moreover, since water vapor very closely follows the perfect gas relationships in the range usually encountered in air con ditioning, the Gibbs-Dalton Rule may frequently be applied to mixtures of dry air and water vapor. Thus, V. - V, = F. (13) r. - r. - tw (14) Pm - P + P- (15) mmh = m,hm + m^A. (16) where Subscript tn denotes mixture; subscript o denotes dry air; subscript w denotes water vapor. Symbol m -- weight of dry air crossing any duct section, pounds per minute. - Using Equations 12, 13, 14, and 15, the relation is obtained as follows: O.RT = nJlT ^ (n, + nJRT p. P* P (17) tcAere cr = total volume, cubic feet. n = number of raols of dry air. n. -- number of raols of water vapor. R = universal gas constant, IMS foot-pounds per (Fahren heit degree) (mol). p# =. partial pressure of dry air. s* partial pressure of water vapor. T = absolute temperature, Fahrenheit degrees. The partial pressure of water vapor in the mixture is then a. P* n + n. P 08) or, the partial pressure of the water vapor in moist air is equal to the product of the mol fraction of the water vapor and the observed pressure of the mixture. A similar expression is obtained for the dry air. Assuming that the perfect gas laws can be applied to water vapor at saturation at low pressures, the partial pressure of water vapor in a saturated mixture may be written as p. " n, + n. (19) where n. = number of mols of water vapor at saturation. The relative humidity may be obtained by combining 16 CHAPTER 3 1959 Guide Equations 18 and 19 and solving for the ratio of mot frac tions. Thus, using perfect gas relationships, < " P- (2Q) p. The humidity ratio W may be obtainedfrom Equation 17: 18.016 p, W 0.622 28561 p. P - P- ' <2U where. 18.016 and 28.906 are the molecular weights of water and dry air, respectively. . ' Equation 16 may be rewritten as. ' A - k, + WK (22) tcAere .. h = enthalpy, Btu per pound of dry air. In relating the enthalpy to. the state of the moist air, the fact that in all applications only differences in enthalpy are involved, allows the arbitrary selection of a datum or tero enthalpy point. Accordingly, from perfect gas relationships, it is posable to write for any temperature t (Fahrenheit) greater than OF . A. = 0.24 1 .. . (23) where it is assumed that the name arbitrary datum of OP is used as in determining the properties of moist air in Table 2. Tobies of Thermodynamic Properties of Moist Air Research' work conducted at the University of Pennsyl vania and at other institutions has shown that the GibbaDalton Rule is inaccurate in varying degrees,' depending on temperature, pressure, and the amount of water vapor pres ent. This inaccuracy is probably due to the effect of: 1. Chemical solution of gas molecules in the water vapor. 2. The finite sire of the molecules causing interference with the free passage of other molecules toward the bouodariesof the system- . . . -v- , . 3. Intermolecular forces of attraction and repulsion. Many attempts have been made to develop an equation of slate which would predict the true states of real gases and vapors. The Van der Waal, Maxwell, and Beattie-Bridgman equations are probably the best known. Unfortunately, these expressions rapidly become much too complicated to be used in everyday calculations and, therefore, engineers find it more convenient to use tables of thermodynamic properties for specific working substances, as these can be prepared by physicists using the best laboratory .equipment and all the refinements of mathematics. . - .. . . Mechanical engineers have long been familiar' with such tables for the.properties of steams Tables of the properties of moist-air, as prepared by Goodenough and others, have been available for some time, but the latest and most precise of such tables are those which have resulted from a coopera tive research agreement between the American Society of Heating and As-Conditioning Engineers and the Towne Scientific School of the University of Pennsylvania. These properties are published herein as Table 2, and are taken from a research report by Goff and Gratch.* -Table 2, which ex perimentally and mathematically takes into account devia tions from perfect gas behavior, such as those listed above, makes the application of the Gibbs-Dalton Rule a less fre quent necessity. In Table 2 there are 15 columns of figures, each column being headed by & suitable symbol. In the following sub paragraphs brief explanations are given of the data in Table 2 under the appropriate column headings. 1(F) " Fahrenheit temperature defined in terms of absolute temperature T by the relation, T - I + 469.67 (24) W, = humidity ratio at saturation. Saturation is the condi tion at which the vapor phase (moist air) may exist in equi librium with a condensed phase (liquid or solid) at the given temperature and pressure (standard atmospheric pressure in the case of Table 2). At given values of temperature and pres sure, the humidity ratio W can have any value from tero to W%.. v9 ~ specific volume of dry air, cubic feet per pound. p, at v, -- d , the difference between tbe volume of moist air at saturation, per pound of dry air, and the specific volume of the dry air itself, cubic feet per pound of dry air. v, = specific volume of moist air at saturation per pound of dry air, cubic feet per pound of dry air. . Aa specific enthalpy of dry air, Btu per pound of dry air. The specific enthalpy of dry air has been assigned the value zero at 0 F, standard atmospheric pressure. .The energy unit Btu is related to the foot-pound by definition, as follows: 1 Btu = 778,3 ft-lb. * A-- A, -- hB , the difference between the enthalpy of moist air at saturation, per pound of dry air, and the specific enthalpy of.the dry air itself, Btu per pound of dry air. - h, -- enthalpy of moist air at saturation per pound of dry air, Btu per pound of dry air. ' - * TM specific entropy of dry air, Btu per (pound) (Fahren heit degree). It will be noticed that the specific entropy of dry air has been assigned the value zero at 0 F and standard atmos pheric pressure. j,, = the difference between the entropy of moist air at saturation, per pound of dry air, and the specific entropy of the dry air itself, Btu per (pound of dry air) (Fahrenheit degree). ' 8, ** entropy of moist air at saturation per pound of dry air, Btu per (pound of dry air) (Fahrenheit degree). ' ' Km -- specific enthalpy of condensed water (liquid or solid) at standard atmospheric pressure, Btu per pound of water. The specific enthalpy of liquid water has been assigned the value zero at 32 F, saturation pressure (0.0SS5S6 peia). av *= specific entropy of condensed water (liquid or solid) at standard atmospheric pressure, Btu per (pound of water) (Fahrenheit degree). The specific entropy of liquid water has been assigned tbe value zero at 32 F, saturation pressure (0.088586 psia). ' p, -- saturation pressure of pure water vapor, pounds per square inch or iocnes of mercury (absolute pressure). At a given pressure, moist air can be saturated at any temperature, though this requires that it have a definite humidity ratio W, and that the coexisting condensed phase contain a definite, but very small, quantity of dissolved air. On the other hand, ure water vapor (steam) below the critical temperature, can Se saturated at only one temperature for a given pressure. The values of saturation pressure listed in Table 2 have been com puted from the formulas of Goff and Gratch. THERMODYNAMIC PROPERTIES OF WATER AT SATURATION Since water vapor at low pressures acts almost as a perfect gas, the enthalpy of water vapor should also be a function only of tiie temperature within these limits. Therefore, the enthalpy of the water vapor may be expressed as approxi mately equal to the enthalpy of saturated vapor at the dry- f t Thermodynamics 17 bulb temperature of the mixture. Substituting these values in Equation 22, the enthalpy of the mixture becomes A 0.24 i -r n'ht i25) cient A for several higher temperatures, the value of y at which the correction term 5 attains its maximum value, and the maximum value of f> term there attained. - The correction term for the enthalpy is where hr is the value of the enthalpy of saturated vapor at ~ the^ temperature t, and is obtained from Table 3. Table 3 offers revisions to existing steam table data with - M(1 - m)B 1 + otP> (31) extensions downward to --160 F. These revisions and ex tensions were a- necessary preliminary to the construction of Table 5 gives the values of the coefficient B and maximum . values of h, the maximum values occurring at the same de- Table 2. A detailed explanation of.,the methods employed in-. - - gree of saturation as e. the construction of Table 3 is given in a papeT by John A. - Corrections for the entropy consist of two terms: f which Goff and S. Gratch.* ' ' As in Table 2, the temperature scale used as argument in is defined as Table 3 is the Fahrenheit scale defined in terms of absolute temperature T by Equation 24. The symbols'used as column p(1 -- n)C 1 + aW# (32) headings in;.Table 3 are the same as those used in'; steam tables, and-have the same meaning.'' .. Properties of water above212 F from Keenan and Keyes* and s, the so-called: mixing entropy, which contributes the ' larger part of the error. The mixing entropy is defined as are given in Table 4. ` ' DEGREE OF SATURATION ' 8 = 0.1579 1(1 + yaW,) logu(l + yaW, -- yaW, logisOi) . (33) - y(l + aW.) log,,(l + aW.)) Degree of saturation has previously been defined as the' ratio of the actual humidity ratio to the humidity ratio of-' saturated air at the same dry-bulb temperature and baro metric pressure. This may be stated mathematically as Table 5 lists the values of the coefficient C, the maximum values of a and i and-the values of y at which they occur. The maximum s occurs at the same degree of saturation as the maximum values of v and A. Obviously the degree of saturation y can have any. value from - zero (dry air) to unity (moist air at saturation). The degree of saturation is conveniently used to interpolate values for the enthalpy, specific volume, and entropy of moist air from the data of Table 2. Within the estimated precision of the data of Table 2, at temperatures below 150 F, the volume ti, enthalpy A, and entropy , of moist air per pound of dry air at any degree of saturation y may be computed from the simple relations: - p = p. + **. (27) A = A. 4- yhm. . (28) 8 = 8 + y,, (29) Thus, the degree of saturation is used in conjunction with Table 2 in the same manner-as the quality is used with tables of the thermodynamic properties of steam. ` - THE ASHAE, PSYCHROMETRIC CHART A psychrometric chart is a graphical representation of the thermodynamic properties of moist air. To be of real value in the solution of engineering problems, it must have distinc tive features which aid in problem analysis. An examination of psychrometric mass and energy balances shows that no properties other than enthalpy and humidity ratio are required for the solution of problems. It is logical, then, to use these properties as the coordinates of a psychro metric chart. This was initially done by Mollier in 1923,7- * and is the arrangement followed in the chart included with The Guide. The ASHAE Perchrometric Chart is based on the best thermodynamic data available today, namely, those of Goff and Gratch, as given in Table 2. The chart is plotted on oblique coordinates of enthalpy and humidity ratio; the enthalpy axis making an angle of approximately 40 deg with the humidity ratio axis. This is shown in Fig. 3. For practical use,1 the inclusion of dry-bulb and wet-bulb temperatures, volumes, and indexes of the condition of the Correction of Table 2 for Temperatures Above 150 F The simple relations expressed in Equations 27, 28, and 29 . give the properties of unsaturated air with satisfactory pre cision for most engineering design problems. Above 150 F, when greater precision than that obtained by Table 2 is required, these simple relations can be adjusted by the addi tion of supplementary terms. To correct the volume, it is necessary to add a correction term p which is defined as _ ?u - <->4 1 + aW* m ' where o denotes the ratio of the apparent molecular weight of dry air (28.966) to the molecular weight of water (18.016). and is equal to 1.6078. Table 5 gives the valuesof the coeffi- fig. 3____ Basic Coordinates of ASHAE Psychrometric Chart 18 CHAPTER 3 1959 Guide Table 2 .... Thermodynamic Properties of MO/ST Aifi* (Standard Atmospheric Pressure, 29.921 in. Hg) r.mp. IW -100 -110 -- ISO -100 -80 -00 -to --IS Humidify Ratio w, x >0* Volume ft/tt. dry ,, fisthatpy Btu/lb dry h. h.. h. Entropy Btu per(*E) (lb dry aft) ,t ,4 Condensed Water Enthalpy Entropy Blu/lb fSaST Vap. Press In. Hg h" Sir P. X 10* I5r 0.0002120 7.830 0.000 0.002109 8.039 0.000 0.01600 8.S37 0.000 0.09772 0.4930 9.040 9.553 0.000 0.000 0.000 3.118 10.059 0.000 S.406 8.180 10.414 10.617 0.001 0.001 0.002 0.002 7.520 8.029 8.150 8.537 9.046 9.553 10.059 10.415 10.567 10.619 -38.504 --36.088 -34.881 -33.674 -32.468 -28.852 -28.444 -24,037 -21.631 -19.225 -14.410 -12.012 -11.051 -10.090 -9.009 -9.129 -8.168 -7.687 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.001 0.001 0.002 0.003 0.003 0.005 0.007 0.011 0.015 0.022 0.031 0.043 0.049 0.056 0.004 0.073 0.083 0.094 0.106 0.121 0.136 -38.604 -37.296 -30.088 -34.881 -33.074 -32.468 -31.263 -30.057 -28.853 -27.848 -28.444 -25.239 -24.030 -22.833 -21.029 -20.425 -19.220 -11.015 -16.809 -15.602 -14.394 -13.183 -11.969 -11.483 -10.995 -10.607 -10.017 -9.526 -9.035 -8.542 -8.047 -7.551 -0.10300 -0.09508 -0.09121 -0.08365 -0.07997 -0.07634 -0.07277 -0.06234 -0.05897 -0.05237 -0.04913 -0.04280 -0.03969 --0.03663 -0.03360 -0.02766 -0.02649 _0 02532 -0.02186 -0.02072 -0.01733 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000 0.00001 0.00001 0.00001 0.00002 0.00003 o.txxxa 0.00006 0.00009 0.00012 0.00013 0.00014 0.00021 0.00024 0.00034 -0.09121 -0.07634 -0.4800 -217.12 -0.4747 0.0005807 -0.4695 -0.4642 -210.28 -0.4538 0.004710 -0-06234 -203.09 -0.4329 0.03028 -0.04912 -0-04278 -0.03658 -195.51 -- 193.55 -191.57 -0.4121 0.1597 -187.53 -0.3913 0.7130 --0.02754 -181.29 -0.3758 -0-02636 -180.44 -0.3738 2.2702 -0.02165 -0.02048 -0.01699 -177.01 -176.14 -175.27 -173.52 -0.3655 -0.3634 -0.3573 3.7906 6.2093 -145 -125 -105 -85 ' --65 -48 -40 -32 Tump. m Humidity Ratio W. X tO* ft/lb dry ,, T. -30 1.404 10.830 0.002 10.822 0.003 -22 2.344 11.022 0.004 11.020 0.005 -17 3.120 11.149 0.000 11.155 0.007 -13 3.903 11.250 0.007 U.2S7 --9 4.805 11.351 0.008 11.359 --0 0.010 -8 6.040 11.4S2 0.011 11.403 0.012 0.013 -1 7.469 11.553 0.014 11.567 B.739 0.015 0.010 S 9.204 11.054 0.017 11.671 5 0.019 11.724 Enthalpy Bfu/flj dry oft ' Btu per (*f) (Jb dry air) Condensed Water -7.207 -6.720 -5.765 -5.285 -4.083 -3.843 -3.123 -3.402 -2.162 -1.681 -1.441 -1.201 -0.961 -0.721 -0.240 0.000 0.340 0.721 0.961 1.201 1.441 h. 0.154 0.173 0.196 0.319 0.246 0-277 0.293 0.310 0.328 0.348 0.389 0.411 0.461 0.487 0.514 0-543 0.574 0.600 0.639 0.675 0.712 0.751 0.792 0.835 0.880 0-928 0.977 1.030 1.085 1.143 h* --7.053 -6.553 -6.050 -5.546 -5.039 -4.527 -4.171 -4.014 -3.755 -3.495 -3.235 -2.974 -3.711 -2.446 -2.181 -1.915 -1.648 -1.379 -1.107 -0.835 -0.563 -0.286 -0.009 o.n 0.553 0.835 1.120 1.408 1.698 1.991 2.2S8 2.583 -0.01631 -0.01509 -0.01398 -0.01287 -0.01177 -0.01067 -0.01012 -0.00958 -0.00904 -0.00850 -0.00796 -0.00743 -0.00689 -0.00638 -0.00582 -0.00529 -0.00475 -0.00422 -0.00369 -0.00316 -0.00210 -0.00157 -0.00105 --0.00057 0.00000 0.00059 0.00104 0.00260 0.00312 0.00038 0.00042 o.ooots 0.00054 0.00061 0.00068 0.00072 0.00078 0.00080 0.00084 0.00089 0-00094 0.00099 0.00104 0.00109 0.00115 0.00121 0.00128 Q.0013S 0.00143 0.00149 0.00157 0.00165 0.00174 0.00163 0.00202 0.00212 0.00222 0.00246 0.00258 Enthalpy Btu/lb Entropy Btu per (*F)(Lb) *- Vap. Press In. Hg ?. X 10* -0.01466 -0.01233 --0.0US32 -171.75 -169.97 -168.17 --J67.28 -0.3531 -0.3490 -0.3469 -0.3449 -0.3438 0.99885 1.4107 -0.00766 -0-00649 -0.00590 --0.0QS32 -0.00414 -0-00334 -166.35 -0.3408 -165.90 -0.3398 -165.44 -0.3387 -164.98 -0.3377 -164.52 -0.3367 -163.60 -0.3346 -163.14 -0.2336 1.7666 3.2035 -0.00174 -161.74 -0.3305 2.7377 0.00008 0.00069 0.0Q131 0.00254 0.00316 -160.34 -159.87 -0.3275 -0.3264 -0.3254 -157.99 -0.3223 3.3885 4.1785 0.00570 -156.09 -0.3182 5.1339 -34 -20 -18 -14 -10 ` -6 -3 1 6 Thermodynamics 19 Table 2.... Thermodynamic Properties of MOIST AIR* (Standard Atmospheric Pressure. 29.92) in. Hg) (Contimed) fabr. Temp. Hamidity Ratio W. X 0* Volume c ft/lb dry oft - 7 8 9 1.130 t.tss 1.251 1.215 11.756 11.781 11.806 11.831 0.031 0.022 0-034 0.025 11.777 11.803 11.830 11.856 11 13 18 1.383 1.4M 1.523 1.606 11.857 11.882 11.907 11.933 0.026 0.028 0.029 0.030 11.883 11.910 11.936 11.963 15 16 17 1.687 1.772 1.861 1.953 11.958 11.983 12.009 13 034 0-031 0.034 0.035 0.038 11.990 13.017 12.044 13.072 19 20 31 2.061 2.151 2.2S8 2.369 12.059 12.084 12.110 12.135 0.040 0.042 0.044 0.046 12.099 12.126 12.154 12.181 23 24 25 26 2.483 2.606 2.733 3.865 12.160 13.IBS 12.211 12.236 0.049 0.051 0.054 0 057 12.209 12.237 12.285 12.293 27 23 29 30 3.003 3.147 3.297 2.454 12.262 11.287 12.312 12.338 0.059 0.062 0.065 0.066 12.321 12.349 12.377 12.406 31 32 32* 33 3.617 3.768 3.783 3.944 12.363 12.388 12.388 12.413 0.071 0.076 0-075 0.079 12:434 13.463 13.463 12.492 34 35 36 37 4.107 4.273 4.450 4.691 12.438 12.464 12.489 12.514 0.082 0.085 0.069 0.092 12.520 13.549 12.578 12.607 Enthalpy Btu/lb dry oft Bto per (*F| (lb dry air) Condensed Water h. 1.681 1.922 2.162 3.402 2.642 2.882 3.122 3.363 3.603 3.843 4.083 4.324 4.664 4.804 5.044 6.284 5.525 6.765 6.005 6.243 6.485 6.726 6.966 7.206 7.446 7.685 7.686 7.927 8.167 8.407 .8.647 8.887 h.. 1.302 1.266 1.232 1.401 1.474 1.550 1.630 1.713 1.800 1.892 1.988 2.088 2.192 2.303 3.416 1.536 3.661 2.792 3.939 2.072 3.221 3.377 3.540 3.709 3.887 4.071 4.072 4.242 4.418 4.601 4.791 4.987 b. 3.883 3.188 3.494 3.803 4.116 4.432 4.753 5.076 5.403 5.735 6.071 6.413 6.766 7.106 7.460 7.820 8.188 8.657 8-934 9.317 9.706 10.103 10.606 10.915 11.333 11.758 11.758 12.169 12.685 18.008 13.433 13.874 0.00364 0.00418 0.00467 0.00518 0.00569 0.00620 0.00671 0.00721 0.00772 0.00823 0.00873 0.00923 0.00973 0.01023 0.01073 0.01123 0.01173 0.01233 0.01273 '0.01322 0.01372 0.01421 0.01470 0.01519 0.01568 0.01617 0.01617 0.01660 0.01715 0.01764 0.01812 0.01861 ... 0.00271 0.00285 0.00299 0.00314 0.00330 0.00346 0.00363 0.00380 0.00399 0.00418 0.00438 0.00459 0.00481 0.00504 0.00S28 0.00553 0.00579 0.00607 0-00635 0.00665 0.00696 0.00728 0.00761 0.00796 0.00832 0.00870 0.00870 0.00904 0.00940 0.00977 0.01016 0.01058 inthalpy Btu/Lb bw Entropy Btu per CFXlb) *- Vap. Press In. Hg . X 10* 0.00635 0.00700 0.00766 0.00832 0.00899 0.00966 0.01034 0.01101 0.01171 0.01340 0.01311 0.01383 0.01454 0.01527 0.01601 0.01676 0.01752 0.01830 0.01908 0.01987 - 0.02068 0-02149 0.02231 0.02315 0.02400 0.02487 0.02487 0.02570 0.02655 0.02741 0.02828 0.02917 -155.61 -155.13 -164.65 -154.17 -0.3173 -0.3162 -0.3153 -0.3141 -153.69 -153.21 -153.72 -152.24 -0.3131 -0.3121 -0.3111 -0.3100 -151.76 -151.37 -150.78 -150.29 -0.3090 -0.3080 -0.3070 0.3059 -149.80 -149.31 -148.82 -148.33 -0.3049 -0.3039 -0.3029 -0.3018 -147.84 -147.34 -146.85 -146.35 -0.3008 -0.2998 -0.2988 -0.2977 -I4S.6S -143.38 -144.88 -144.36 --0.2967 -0.2957 -0.2947 -0.2936 -143.86 -143.36 0.04 1.05 -0.2926 -0.2918 0.0000 0.0020 2.06 0.0041 2.06 0.0061 4.07 0.0081 5.07 0.0102 5.4022 5.6832 5.9776 6.2858 6.6085 6.9463 7.2997 7.6696 8.0565 8.4613 8.8843 9.3287 9.7889 10.272 10.777 11.305 11.858 12.431 13-032 13.559 14.313 14.966 15.709 16.432 17.227 18.035 18.037 18.778 19.548 20.342 21.166 22.020 m' 7 8 9 10 11 12 13 14 15 16 17 IB 19 20 21 22 23 24 25 26 87 28 29 30 31 32 32* 33 34 35 36 37 Eafcr. m Humidify Ratio w, x io* Vofrote cv ft/fb dry air ... Enthalpy Bfu/lb dry air h. be. b. 38 39 40 42 43 44 43 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 63 62 64 65 66 67 68 69 4.818 5.012 5.213 5.421 5.638 5.860 6.091 6.331 6.578 6.835 7.100 7.374 7.6S8 7.952 8.256 8.569 8.894 9.229 9.575 9.934 10.30 10.69 11.08 11.49 11.91 12.35 12.80 13.26 13.74 14.24 14.75 15.28 11.540 I2.56S 12.690 12.616 0.097 0.101 0.105 0.109 12.641 12.666 12.691 12.717 0.114 .0.119 0.124 0.129 12.742 12.767 12.792 12.816 0.134 0.140 0.145 0.151 12.843 12.868 12.894 12.919 0.158 0.164 0.170 0.178 12.944 12.970 12.993 11.020 0.185 ' 0.192 0.200 0.208 13.043 13.071 13.096 13.121 0.216 0.224 0.223 0.20 13.147 13.172 13.197 13.222 0.251 0.281 0.271 0.282 12.247 12.273 13.298 13.323 0.292 0.303 0.315 0.327 12.637 11.666 12.693 13.725 9.128 9-368 9.608 9.848 12.755 12.785 12.815 12.846 10.088 10.329 10.669 10.809 12.876 12.907 12.938 12.969 It.049 11.289 11.330 11.770 13.001 13.032 13.064 13.097 12.010 12.250 12.491 ' 12.731 13.129 13.162 13.195 13.228 12.971 13.211 13.452 13.692 13.281 13.295 12.229 13.383 13.932 14.172 14.413 14.653 13.398 13.433 13.488 13.604 14.893 16.134 13.374 13.614 13.539 13.576 13.913 13.650 15.855 t6.095 16.335 16.576 5.191 5.403 5.622 5.649 6.084 6.828 6.580 6.841 7.112 7.391 7.681 7.981 8.291 8.612 8.945 9.289 9.644 10.01 10.39 10.79 11.19 11.61 13.05 11.50 12.96 13.44 13.94 14;45 14.98 13.53 16.09 16.67 14.319 14.771 IS.230 15.697 16.171 16.657 17.149 17.650 18.161 18.680 19.211 19.761 20.301 20.883 21.438 22.020 22.613 23.22 23.84 34.48 25.12 35.73 28.48 27.15 27.85 28.67 29.31 30.06 30.83 31.03 32.42 33.23 * Compiled by Jobs A. Goff end 8. Gretch- * _ * Extrapolated (o represent meinstable equilibrium *tb uadereooled liquid. Entropy Bfv per (*f) (b dry aid Condensed Water s ... * Enthalpy Btu/Lb Entropy Btu per CO(Lb) Vap. Press In. Hg b. P. 0.01909 0.01957 0.02005 0-02053 0-01097 0.01139 0.01183 0.01238 0.02101 0.03149 0.02197 0.02345 0.01275 0.01323 0.01373 0.01423 0.03293 0.02340 0.02387 0.02434 0.01478 0.01834 0.01591 0.01630 0.02481 0.02528 0.02575 0.02822 0.01711 0.01774 0.01839 0.01906 0.02609 0.02718 0.02762 0.02809 0.01976 0.02047 0.02121 0.02197 0.02858 0.02S03 0.02948 0.02994 0.02276 0.02357 0.03441 0.02527 0.03040 0.03086 0.03133 0.03177 0.02818 0.02708 0.02803 0.02901 0.03223 0.0H69 0.03314 0.03380 0.03002 0.03106 0.03313 | 0.03328 0.03006 0.03096 0.01188 0.03281 0.03376 0.03472 0.03579 0.03670 0.03771 0.03874 0.03978 0.04084 0.04192 0.04302 0.04414 0.04528 0.04645 0.04763 0.04883 0.05006 0.05131 0.05259 0.05389 0.05S21 0.05658 0.05794 0.05935 0.06073 0.06333 0.06375 0.06537 0.06683 6.08 7.08 8.09 9.09 10.09 11.10 12.10 13.10 14.10 15.11 16.11 17.11 18.11 19.11 n.n 21.11 22.13 23.12 24.13 25.13 26.13 27.13 28.12 29.13 30.13 31.12 32.12 83.11 34.11 35-U 36.11 87.11 0.0182 0.0142 0.0163 0.0182 0.0202 0.0222 0.0242 0.0282 0.0282 0.0303 0.0321 0.0341 0.0361 0.0381 0.0400 0.0420 0.0439 0.04S9 0.0478 0.0497 0.0517 0-0538 0.0555 0.0574 0.0594 0.0613 0.0682 0.0651 0.0670 0.0689 0.0708 0.0727 0.22904 0.23819 O.S4767 0.25748 0.26763 0.27813 0.28899 0.30023 0.31185 0.32388 0.33629 0.34913 0.36340 0.37611 0.39028 0.40492 0.42004 0.43S65 0.45176 0.46840 0.48558 0.50330 0.S21S9 0.54047 0.55994 0.56003 0.60073 0.62209 0.64411 0.66681 0.69019 0.71430 Fahr HT 38 39 40 41 43 43 44 45 46 47 48 49 60 61 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 " 22 CHAPTER 3 1959 Guide Fahr. Tamp. -WO -144 -WO -- 125 -IH) -100 -80 -00 -46 -28 Table 3 .... Thermodynamic Properties of WATER at Saturation* Abtoiut* Frastun Specific Volume, cu ft per lb Enthalpy, Btv per lb Entropy, Btv per (lb) (*F) Ib/Sq In. In. Hg Sal. Solid vi, xTcr* Sat. Vapor v, x ur* hi 0.004049 0.04028 0.3757 2.291 11.57 48.72 0.01008 0.05303 0.1003 0.1706 0.7649 4.664 15.96 23.44 101.2 0.01722 0-01723 0.01724 0.01724 0.01724 0.01725 0.01726 0.01728 0.01727 0.01728 0.01723 0.01729 0.01729 0.01730 0.01730 0.01731 0.01732 0.01732 0.01733 0.01734 O.OI73S 127.0 211.0 248.4 429.5 0.01736 0-01736 0.01737 0.01737 0.01737 0.01738 38070 11390 6577 3864 1400 802.2 438.6 341.1 318.9 93.42 28.46 19.44 13.56 6.715 4.788 2.496 1.941 1.343 1.191 0.8391 0.8355 36070 20080 11390 6577 3864 2308 1400 863.2 538.6 341.1 218.9 93.53 41.86 28.46 19.55 12.56 9.501 6.715 4.788 3.443 2.496 2.200 1.941 1.715 1.416 i.3a 1.191 1.057 0.9391 0.8345 -222.05 -220.44 -218.82 -317.17 -215.49 -313.80 -212.08 -310.34 -206.58 -206.79 -204.98 -203.14 -201.28 -199.40 -195.56 -193.60 -191.63 -187.58 -185.63 -183.44 -181.34 -180.49 -179.64 -178.76 -177.92 -177.06 -176.19 -176.33 -173.57 *.r Sat. Vapor Sat. SoGd Ji, * 1212.a 1213.02 1214.17 1214.70 1215.22 1215.71 1216.18 1216.63 1217.45 1217.63 1218.17 I2t8.SO 1216.80 1219.08 997.00 -0.47a toot.a 1005.84 -0.4538 1012.47 10t4.68 1016.89 1023.52 -0.4329 --0.4277 -0.4121 4.0460 3.9812 3.8583 3.7428 3.6338 3.6815 3.4815 3.433S 3.2536 Sat. Vapor * 3.383S 3.1800 3.0006 2.8(16 1219.56 1219.76 1219.94 1220.10 1220.23 1220.34 1220.37 1220.40 1220.43 1220.45 1220.48 1220.49 1220.51 1220.53 1220.52 1027.94 1032.36 1034.58 1039.00 1039.88 1040.76 1041.65 1043.a 1044.30 -0.3914 -0.3738 -0.3717 -0.3655 1046.96 -0.3573 3.1702 3.0910 2.7685 2.6996 2.97B6 2.9043 2.0501 2.9359 2.9219 2.9080 2.89a 2.0028 2.6905 2.5784 3.5663 2.5425 2.8S3S 2.4966 1(F) -145 -125 -106 -85 -65 -so -a -40 -32 Fahr. Temp. Ib/Sq In. Specific Volume, cu ft per lb - Enthalpy, Btv par lb Entropy, 8tu per (ib| [*F] tn. Hg Sat. Solid Evap. Sat. Vapor Sot. Solid v. X I0-* x nr* * hi h.,P Sat. Vapor Sat. Solid ># >i Sat. Vapor -30 0.5440 0.7003 0.01738 0.01738 0.01738 0.01739 --21 0.4509 1.122 0.01739 0.01739 0.01739 0.01740 -17 0.7333 1.493 0.01740 0.01740 0.01740 -13 0.8173 1.BS7 0.01740 0.01740 0.01740 0.01741 -0 1.143 2.227 0.01741 0.01741 0.01741 0.01741 -5 1.419 3.888 0.01741 0.01742 -1 1.744 3.572 0.01743 0.01743 3 3.W1 4.400 0.01743 0.01743 Compiled by John A. Go8 end 8. Gttteh. 7.441 6.634 5.921 5.290 4.732 4.237 3.596 3.407 3.228 3.000 2.001 2.609 3.349 1.909 1.723 1.657 1.408 1-340 1.275 1.100 7.441 6.634 5.921 5.290 4.732 4.237 4.011 3.797 3.596 3.407 3.223 3.060 3.901 2.750 3.609 2.476 3.349 2.229 2.116 3.010 1.909 1.814 1.723 1.638 1.557 1.481 1.408 1.340 1.257 1.214 1-155 1.100 -171.80 -170.01 -168.21 -167.31 -166.85 -165.48 -165.03 -164.11 -- 163.66^. -163.18 --t63.28 -161.79 -161.83 -159.92 -159.45 -158.51 -158.04 -157.09 -156.14 1220.52 1220.52 1220.51 1220.60 1220.49 1220.47 1220.46 1220.45 1220.43 1220.42 1220.41 1220.39 1220.38 1230.36 1230.34 1220.32 1220.30 122Q.28 1220.26 1230.23 1220.21 1220.15 1220.13 1220.10 1220.07 1220.04 1220.01 1219.97 1219.94 1219.90 1219.88 1050.49 1052.28 10S3.14 1054.91 1055.35 1056.67 1057.13 1058.00 10S8.44 1058.88 1059.76 1060.21 1060.65 1061.97 1002.41 1062.85 1063.29 1063.74 --0.3490 -0.3429 -0.3388 -0.3347 -0.3316 -0.3300 -0.3275 -0.3264 -0.2254 --0.2224 -0.3203 -0.2193 -0.3182 2.8274 2.8012 2.7865 2.7757 2.7632 2.7568 2.7444 2.7383 2.4523 2.4203 2.3995 2.7198 2.7138 2.7076 2.7016 2.6956 2.6896 2.6836 3.6777 3.6718 3.6658 2.6600 3.6483 2.6425 2.6367 2.6309 2.6252 2.6194 2.3841 2.3791 2.3740 3.3590 3.3541 3.34a 2.3394 3.3349 2.3201 2.2154 2.3106 3.3012 F) -24 -18 -14 -10 -9 -8 -2 3 6 .Thermodynamics Ttw.mvsdvnamic Properties of WATER at Saturation* (Continued) 8538 8888 SS8 23 "I 24 CHAPTER 3 1959 Guide Table 3 . . .. Thermodynamic Properties of WATER at Saturation* (Continued} Fabr. Temp. m Absolute Prersure tb/Sq(n. Specific Volume, cu ft per li Enthalpy, Bht par lb Entropy, BbJ per (lb) (*F) Evap. Sot. Vapor Sat. lipoid b/c b. 0.33856 0.40190 0.11564 0.44435 0.45935 0.47473 0.79113 Q.81829 0.S4S26 0.87506 0.90472: 0.93524 0.96666 0.999QD 1.0323 1.0665 1.1017 . 1.1380. 0.01606 0-01406 0.01606 0.01606 0.01606 0.01007 0.01607 0.01607 0.01607 0.01608 0.01608 813.95 768.36 763.73 739.95' 717.01 694.88 673.52 652.91 633.01 613.60 595.25 577.34.. 717.03 694.90 673.54 652.93 633.03 613.82 695.27 577.38 41.07 42.06 43.00 44.03 45.06 46.06 47.06 48-05 49.05 50.05 51.05 1052.58 1053.01 1051.46 1050.33 1049.76 1049.19 1092.65 1093.08 1093.52 1093.95 1094.28 1094.82 1095.25 1095.68 1096.12 1096.65 1096.98 1097.42 0.08582 0.08769 0.08954 0.09140 0.09325 0.09510 0.09694 0.09878 1.9797 1.9749 1.9701 1.9654 1.9607 1.9560 1.9513 1 9466 2.0330 9.0651 2.0522 2.0494 2:M65 2.0437 2.0403 1.1752 1.2136' 1.2530 1.2935 '1.3351 1.3779 1.4219 1.4671 0.01608 0.01609 0.01609 0.01609 0.01610 0-01610 0.01610 0.01610 560.04 543.33 637.19 511.60 560.06 543.35 527.21 511.62 496.54 481.98 467.90 454.28 66.04 67.04 58.04 59.03 1045.23 1044-67 1044.10 1043.54 1042.97 1042.40 1041.84 1099.58 1100.01 U0Q.44 1100.87 0.10062 0.10246 0.10429 0.10611 0.10794 0.10976 0.UIS6 0.11339 2.0214 2.0187 2.0160 0.74340 0.76634 0.79091 0.B1564 1.5136 1.5613 1.4103 1.6607 0.01611 0.01611 0.01611 0.01613 441.10 428.38 416.97 404.17 441.12 428.40 416.09 1041.27 1040.70 1040.13 1101.30 1101.73 1102.16 1102.59 0.11520 0.11701 0.11881 0.12061 3.0026 2.0000 1.9974 1.9947 0.01612 0.01612 0.01612 0.01613 392.65 331.51 370.73 360.30 392.67 3B1.6S 370.75 380.33 64.02 65.03 66.02 67.02 1103.02 1103.4$ 1103.88 1104.31 0.04959 0.97354 1.0083 1.0383 1.0700 1.1031 1.1351 1.1688 1.9334 1.9923 2.0529 2.1149 2.1786 2.2440 2.3110 2.3798 0.01613 0.01614 0.01614 0.01614 0.01614 0.01615 0.01615 0.01616 350.20 340.42 330.06 321.80 304-34 296.02 287.96 350.22 840.44 330.98 321.82 312.95 304.36 296.04 287.98 68.02 69.01 70.01 71.01 72.01 73.01 74.01 75.00 1036.16 1035.68 1035.01 1034.44 1033.87 1033.29 1032.73 1104.74 1105.17 1105.59 1106.02 0.12957 0.13135 0.13313 0.13490 1.8480 1.8437 1.8394 0.13844 0.14031 0.14197 1.9819 1.9793 1 9768 1.9743 1.9718 1.9693 1.9668 Fabr. Absolute Ftessure Specific Volume, cu ft per lb Enthalpy, 6hr par lb Entropy, Bfa per (lb) (*f) ri5T Lb/Sq In. Sat. Liqvid bf Evap. Sat. Vapor Sot. Liquid Evap. bfi bt Sat Vapor 1.2035 1.2390 1.2754 1.3128 1.3510 1.3902 1.4305 1.4717 1.5139 1.6671 16014 1.646S 1.6933 1.7409 1.7897 1.6396 3.1703 3.2606 3-3930 3.4477 3.6446 3.6429 3.7455 0.01616 0.01616 0.01617 0.01617 0.01617 0.01618 0.01618 0.Q1618 0.01619 0.01619 0.01620 0-01630 0.01621 o.omi 0.01623 372.58 265.34 258.14 251.25 244.57 238.10 231.82 225.73 219.83 214.10 203-16 197.93 192.85 251.27 244.59 233.13 231.84 225.75 219.8$ 214.13 208.56 203.18 197.95 192.87 187.9$ 76.00 77.00 78.00 79.00 1033.16 1031.68 1031.01 1030.44 1025.28 1024.70 1024.13 1023.54 1108.1$ 1108.58 1109.01 1109.44 1109.86 1110.29 1110.71 lm.w 1111.66 1111.98 Utt.ll 1112.83 1113.28 1113.68 1114.10 1114.52 0.14273 0.1450 0.14734 0.14899 1.3015 1.7973 1.7932 1.7849 1.7809 1.7767 1.7727 1.7687 1.7647 1.7606 1.7566 1.9619 1.9595 1.9570 1.9546 1.9522 1.9498 1.9474 1.9450 1.9426 1.9403 1.9379 1.9356 1.9333 1.9310 1.9288 1.9264 1.9430 1.9960 3.0514 3.1075 2-1649 2.2X37 3.3838 3.8496 3.9561 4.0651 4.1768 4.2910 4.4078 4.5274 4.6493 0-01622 0.01622 0.01623 0.01623 0.01624 0-01624 0.01636 0.01625 183.15 178.51 174.00 169.63 165.38 161.36 157.25 153.36 183.17 178.53 174.02 165.40 161.28 157.27 153.38 91.98 92.98 93.98 94.97 1022.96 1022.39 1021.81 1021.24 1114.94 1115.37 1115.79 1116.21 U16.63 1117.05 1117.47 1117.89 0.17830 0.18000 0.18170 0.18339 1.7526 1.7488 1.7446 1.7407 1.9241 1.9218 1.9195 1.9173 1.9150 1.0128 1.9106 1.9084 2.6055 2.6743 2.7446 2.8165 5.3049 6.4450 5.5801 5.7345 0.01626 0.01628 0.0I62S 0.01627 0.01627 0.01626 0.01628 0.01629 149.58 145.91 142.34 133.87 135.50 132.22 129.04 125.94 149.60 145.93 142.36 135.52 132.24 129.06 125.94 99.97 100.97 101.97 102.97 103.97 104.97 105.97 106 97 1018.34 1017.76 1017.18 1016.59 1016.01 1015.43 1014.8$ 1Q14.26 1118.31 1118.73 1119.15 1119.56 1119.98 1120;40 1120.82 1111.23 0.18508 0.1S676 0.18845 0.19013 0.19181 0.19348 0.19516 0.19683 1.7211 1.7172 1.7134 1.7095 1.7056 1.7018 1.6979 1.6943 1.9062 1.9040 1.9018 1.8996 1.6974 I.6953 1.883! 1.8910 2.8900 3.9651 3.0419 3.1204 6.0371 6.1934 6.3532 0.01629 ' 0.01630 0.01630 0.01631 * Compiled by John A. Goff end 8. Gretch. 122.94 120.01 117.16 114.40 122.96 120.03 117.18 114.42 107.96 108.96 109.96 110.96 1013.89 1013.11 1013.53 1011.94 1121.65 1122.07 1122.48 1122.90 0.19850 0.20016 0.20182 0.20348 1.6903 1.6365 1.6826 1.6790 1-8867 1.8846 1.8825 Fabr. rjpr Fabr. Temp. ^Thermodynamics 25 'Tempi liF) t y. . 147 U6 151 155 159 163 167 m . 171 172 174 175 176 . 177 Table 3____ Thermodynamic Properties of WATER at Saturation* (Conc/uded) Absolute Pressure P Lb/Sq In. In. Hp Specific Volume, ctr taertb FllAtifnw Alt, mm & 8ft; w. (IU ,'?! Sot Liquid V V Sat. Vapor Sat. liquid hi . Evap. b/t Sat. Vapor Sat. liquid b. */ Evap. */ Sat. Vapor *t 6.5194 3.4517 7.0277 3.8124 4.2049 7.3872 7.6737 7.7623 7.9566 8.3548 8.5607 4.6304 5.0921 5.3372 5.5921 5.7233 6.1328 6.2746 6.4192 6.7168 6.8699 7.0259 ' 8.9653 9.3043 9.4276 9.6556 10.126 10.368 10.615 10.867 11.124 11.388 11.663 11.925 12.487 12.775 13.070 13.370 13.676 13.987 14.305 0.01631 0.016330.01633 . 111.70 ' 109.09 106.64 104.06 0.01633 0.01634 0.01635 101.65 09.300 97.022 94.799 0.01635' ' '= 0.01036 0.01636 0.01637 93.635 90.538 88.477 86.480 0.01637 0.01638 0.01638 0.01639 84.538 83.643 80.798 79.001 0.01639 0.01640 ' 0.01640 0.01641 77.351 75.646 73.685 73.387 0.01643 0.01643 0.01643 0.01643 70.690 - 69.153 07.654 66.194 0.01644 0.01644 0.01645 94.770 63.383 63.029 60.710 0.01646 0.01647 0.01647 0.01648 59.423 58.168 66.044 65.750 0.01648 0.01949 54.686 53.450 111.72 109.11 106.56 104.08 101.67 99.323 97.038 94.815 93.651 00.644 88.493 86.496 84.653 83.658 80.314 79.017 77.387 75.663 73.901 72.283 70.706 69.169 67.670 66.310 64.788 63.398 63.045 60.736 59.439 68.184 66.960 55.766 54.603 53.466 111.96 113.96 113.96 114.96 115.96 116.96 117.96 118.96 119.96 120.97 131.97 133.67 134.97 135.97 126.97 127.97 128.67 129.97 130.68 ' 131.98 133.68 133.98 131.98 135.98 138.99 137.99 133.96 139.99 141.00 142.00 143.00 144.00 145.00 1011.35 1010.77 1010.18 1009.59 1123.31 1123.73 1124.14 1134.65 1009.01 1008.42 1007.83 1007.34 1134.97 1125.38 1125.79 1126.20 1006.66 1006.06 1005.47 1004.63 1128.62 1127.03 1127.44 1127.65 1004.29 1003.70 1003.11 . 1002.51 1128.26 1128.67 im.08 1129.48 1001.92 1001.33 1000.74 1000.13 1129.89 1180.30 1130.71 1131.11 999.54 908.94 998.35 997.75 1131.53 1131.92 1122.33 1132.73 997.16 996.65 995.95 995.36 1133.14 ' 1133.54 1133.94 1134.35 994.76 994.15 993.55 992.95 1134.75 1135.15 1135.65 1135.05 992.35 1136.35 991.75 . 1136.75 0.20514 0.20679 0.20845 0.21010 0.31174 0.31339 0.21503 0-21667 0.21830 0.31994 0.22157 0.32320 0.32483 0.32645 0.33807 0.23130 0.332930.33453 0.33614 0-23774 0.33935 0.34095 0.34355 0.34414 0.34574 0.34733 0.34693 0.25051 0.25209 0.25387 0.25525 0.25683 0.35811 1.6753 1.6715 1.6678 1.6641 1.6604 1.6567 1.6630 1.6493 1.6457 1.6421 1.6364 1.6343 1.6312 1.6276 1.6239 1.6204 1.6163 1.6133 1.6097 1.6062 1.6037 1.6990 1.5956 1.5920 1.5887 1.S8S3 1.5817 1.5783 1.6748 1.5713 1.5679 1.5644 1.5611 1.5577 1.8804 1.8783 1.8763 1.6742 1.8721 1.8701 1.8680 1.8660 1.8640 .1.8620 1.8600 1.8580 1.8560 1.8540 1.8530 1.8501 1.8491 1.8462 1.8442 1.8423 1.8404 1.8384 1.8365 1.8346 1.8328 1.8309 1.8290 1.8271 1.8353 1.8234 1.8216 1.8197 1.8179 1.8161 Fabr. Temp. HF) Absolute Pressure Specific Volume, cu '1 par lb Enthalpy, Btzj par lb Entropy 8ht par (lb) (aF) Lb/Sq In. In. He Sat. Liquid *7 V* Sat. Vapor Sat. Liquid Sat. Vapor Sat. liquid Evap. Sat. Vapor r bf bf. b. */ ft ' <r 178 179 180 18V 183 183 184 185 ' 186 187 138 189 190 ' 191 193 193 194 195 196 197 198 199 too 201 202 203 204 205 206 207 208 : 209 210 211 213 7.6801- 8.2035 8.3815 9.1423 9.3403 9.5420 9.7473 9.9563 10.386 10.830 U.DSS 11.526 11.767 12.260 12.770 13.031 13.297 13.568 13.843 14.123 ' 14.407 14.696 14.629 14.959 0.01650 15.637 0.01651 15.988 . 16.341 16.703 17.071 0.01653 0.01654 17.839 18.318 18.614 0.01854 0.01655 0.01656 19-017 0.01657 19.846 20.271 0.01658 0.01659 20.704 21.145 21.694 33.050 0.01659 0.01660 0.01661 0.01661 33.515 32.987 33.468 23.957 0.01662 0.01663 0.01663 0-01694 24.455 24.961 0.01665 36.000 ' 0.01667 36-633 37.074 37-625 28.185 0.01668 0.01669 38.754 39.333 ' 39.931 0.01670' .0.01671 53.341 61.360 49.173 48.168 47.187 46.229 45.294 44.881 43.489 42.619 41.769 40.939 40.138 39.337 . 38.563 37.807 37.069 38.348 >5.643 34.954 34.381 33.63313.980 33.351 31.737 30.649 39.974 29.413 28.338 37.801 37.387 26.784 63.357 51.276 60.230 49.190 48.185 47.304 46.246 45.311 44.398 43.506 42.636 41.786 40.956 40.145 39 354 38.580 37-834 *7.088 36.365 35-660 34.971 34-398 33.640 32-997 31-754 30-566 29.991 39.430 38.880 38.343 27-818 36-801 146.01 147.01 149.01 ISO.03 151.03 152.03 153.03 155.04 156.04 157.05 158.05 159.00 160.06 161.06 162.07 163.08 164.08 165.08 166.09 168.10 169.11 170.11 171.12 173.15 174.14 175.14 in.16 178.17 179.17 180.18 991.14 990.54 9S9.93 989.33 988.72 - 988.12 987.50 966.89 988.28 965.67 985.07 984.46 983.84 983.32 982.61 982.00 981.38 980.70 980.15 979.54 978.9*1 978.29 977.68 977.05 976.43 975.81 975.19 974.66 973.94 973.33 973.69 973.06 971.43 970.81 970.17 1137.15 1137.55 1138.34 1138.74 1139.14 1129.63 1139.93 1140.33 1140.71 1141.11 1141.50 1141.89 1143.38 1142.67 1143.06 1143.45 1143.84 1144.33 1144.63 1145.00 1145.39 1145.78 1146.16 1146.54 1146.93 1147.69 1148.03 1148.46 U48.84 1149.23 1149.60 1149.98 1150.85 0.25998 0.26155 0.38313 0.26468 0.28625 0.26781 0.36937 0.37093 0.37318 0.37404 0.27559 0.27713 0.27868 0.23022 0.28170 0.28330 0.38464 0.28838 0.28791 0.28944 0-29097 0.29250 0.29402 0.29554 0.29706 0.29858 0.30010 0.30161 0.80312 0.30463 0.30614 0.30765 0.30015 0.31065 0.31215 1.5543 I.550S 1.5475 1.5443 1.5408 1.5375 1.5341 1.5303 1.5375 1.5243 1.5309 1.5176 1.5143 1.5111 1.5078 1.S045 1.5018 1.4980 1.4949 1.4917 1.4884 1.4852 1.4820 1.4789 1.4756 1.4725 1.4693 1.4662 1.4631 1.4600 1.4568 1.4536 1.4506 1.4474 1.4444 1.8143 1.8134 1.8106 1.8089 1.8071 1.8063 1.8035 1.6000 1.7983 1.7965 1.7947 1.7930 1.7890 1.7861 1.7844 1.7811 1.7794 1.7760 1.7744 1.7737 1.7711 1-7694 1.7638 1.7603 1.7646 1.7613 1.7597 1.758! 1.7565 Compiled by John A. Goff end 8. Gratch. Fabr. Temp. 144 145 146 147 ' 148 149 150 151 153 . 153 154 155 156 157 158 . 159 160 V61 163 164 165 166 167 168 169 170 171 172 174 175 176 177 Fahr. Isr 176 179 181 182 - 186 190 m 198 203 306 208 210 26 CHAPTER 3 1959 Guide Abs. In. Hg P 0.25 0.50 0-75 1.00 1.5 2 4 6 8 10 12 14 16 J8 20 22 24 26 28 30 tb/Sq In. 14.696 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90 92 94 96 98 100 150 200 300 400 500 f 1 40.23 58.80 70.43 79.03 91.72 101.14 125.43 140.78 152.24 161.49 169.28 176.05 182.05 187.45 192.37 196.90 201.09 205.00 208.67 212.13 212.00 216.32 222.41 227.96 233.07 237.82 242.25 246.41 250.33 254.05 257.58 260.95 264.16 287.25 270.21 273.05 276.80 278.45 281.01 283.49 285.90 288.23 290.50 292.71 294.85 296.94 298.99 300.98 302.92 304.83 306.68 308.50 310.29 312.03 313.74 315.42 317.07 318.68 320.27 321.83 323.36 324.87 328.35 327.81 358.42 381.79 417.33 444.59 467.01 Table 4 .... Properties of SATlfftATED STEAM; Pressure Table* Specific VotuaM Enthalpy Entropy Sat. liquid V Sat. Vapor vt Sat. liquid **/ Sat. Vapor Sal. liquid Evop. Sat. Vapor h/ */ */ 0.01602 0.01604 0.01606 0.01608 0.01611 0.01614 0.01622 0.01630 0.01635 0.01640 0.01644 0.01648 0.01652 0.01655 0.01658 0.01661 0.01664 0.01667 0.01669 0.01672 2423.7 1256.4 856.1 652.3 444.9 339.2 176.7 120.72 92.16 74.76 63.03 54.55 48.14 43.11 39.07 35.73 32.94 30.56 28.52 26.74 8.28 28.86 38.47 47.05 59.71 69.10 93.34 108.67 120.13 129.38 137.18 143.96 149.98 155.39 160.33 164.87 169.09 173.02 176.72 180.19 1071.1 1060.6 1054.0 1049.2 1042.0 1036.6 1022.7 1013.6 1006.9 1001.4 996.7 992.6 988.9 985.7 982.7 979.8 977.2 974.8 972.5 970.3 1079.4 1087.5 1092.5 1096.3 1101.7 1105.7 1116.0 1122.3 1127.0 1130.8 1133.9 1136.6 1138.9 1141.1 1143.0 1144.7 1146.3 1147.8 1149.2 1150.5 0.0166 0.0532 0.0754 0.0914 0.1147 0.1316 0.1738 0.1996 0.2186 0.2335 0.2460 0.2568 0.2662 0.2746 0.2822 0.2891 0.2955 0.3014 0.3069 0.3122 2.1423 2.0453 1.9881 1.9473 1.8894 1.8481 1.7476 1.6881 1.6454 1.6121 1.5847 1.5613 1-5410 1.5231 1.5069 1.4923 1.4789 1.4665 1.4550 1.4442 2.1589 2.0985 2.0635 2.0387 2.0041 1.9797 1.9214 1.8877 1.8640 1.8456 1.8307 1.8181 1.8072 1.7977 1.7891 1.7814 1.7744 1.7679 1.7619 1.7564 0.01672 0.01674 0.01679 0.01683 0.01687 0.01691 0.01694 0.01698 0.01701 0.01704 0.01707 0.01709 0.01712 0.01715 0.01717 0.01720 0.01722 0.01725 0.01727 0.01729 0.01731 0.01733 0.01736 0.01738 0.01740 0.01742 0.01744 0.01746 0.01748 0.01750 0.01752 0.01754 0.01755 0.01757 0.01759 0.01761 0.01762 0.01764 0.01766 0.01768 0.01769 0.01771 0.01772 0.01774 0.01809 0.01839 0.01890 0.0193 0.0197 ' 26.80 24.75 22.17 20.089 18.375 16.938 15.715 14.663 13.746 12.940 12.226 11.588 11.015 10.498 10.029 9.601 9.209 8.848 8.515 8.208 7.922 7.656 7.407 7.175 6.957 6.752 6.560 6.378 6.206 6.044 5.890 5.743 5.604 5.472 5.346 5.226 5.111 5.001 4.896 4.796 4.699 4.606 4.517 4.432 3.015 2.288 1.5433 1.1613 0.9278 180.07 184.42 190.56 196.16 201.33 206.14 210.62 214.83 218.82 222.59 226.18 229.60 232.89 236.03 239.04 241.95 244.75 247.47 250.09 252.63 255.09 257.50 259.82 262.09 264.30 266.45 268.55 270.60 272.61 274.57 276.49 278.37 280.21 282.02 283.79 285.53 287.24 288.91 290.56 292.18 293.78 295.34 296.89 298.40 330.51 355.36 393.84 424.0 449.4 970.3 967.6 963.6 960.1 956.8 953.7 950.7 947.9 945.3 942.8 940.3 938.0 935.8 933.7 931.6 929.6 927.7 *925.8 924.0 922.2 920.5 918.8 917.1 915.5 913.9 912.3 910.8 909.4 907.9 906.5 905.1 903.7 902.4 901.1 899.7 898.5 897.2 895.9 894.7 893.5 892.3 891.1 889.9 888.8 863.6 843.0 809.0 780.5 755.0 1150.4 1152.0 1154.2 1156.3 1158.1 1159.8 1161.3 1162.7 1164.1 1165.4 1166.5 1167.6 1168.7 1169.7 1170.7 1171.6 1172.4 1173.3 1174.1 1174.8 1175.6 1176.3 1176.9 1177.6 1178.2 1178.8 1179.4 1180.0 1180.6 1181.1 1181.6 1182.1 1182.6 1183.1 1183.5 1184.0 1184.4 1184.8 1185.3 1185.7 1186.1 1186.4 1186.8 1187.2 1194.1 1198.4 1202.8 1204.5 1204.4 0.3120 0.3184 0.3275 0.3356 0.3431 0.3500 0.3564 0.3623 0.3680 0.3733 0.3783 0.3831 0.3876 0.3919 0.3960 0.4000 0.4038 0.4075 0.4110 0.4144 0.4177 0.4209 0.4240 0.4270 0.4300 0.4328 0.4356 0.4383 0.4409 0.4435 0.4460 0.4484 0.4508 0.4531 0.4554 0.4576 0.4598 0.4620 0.4641 0.4661 0.4682 0.4702 0.4721 0.4740 0:5138 0.5435 0.5879 0.6214 0.6487 1.4446 1.4313 1.4128 1.3962 1.3811 1.3672 1.3544 1.3425 1.3313 1.3209 1.3110 1.3017 1.2929 1.2844 1.2764 1.2687 1.2613 1.2542 1.2474 1.2409 1.2346 1.2285 1.2226 1.2168 1.2112 1.2059 1.2006 1.1955 1.1906 1.1857 1.1810 1.1764 1.1720 1.1676 1.1633 1.1592 1.1551 1.1510 1.1471 1.1433 1.1394 1.1358 1.1322 1.1286 1.0556 1.0018 0.9225 0.8630 0.8147 1.7566 1.7497 1.7403 1.7319 1.7242 1.7172 1.7108 1.7048 1.6993 1.6941 1.6893 1.6848 1.6805 1.6763 1.6724 1.6687 1.6652 1.6617 1.6585 1.6553 1.6523 1.6494 1.6466 1.6438 1.6412 1.6387 1.6362 1.6338 1.6315 1.6292 1.6270 1.6248 1.6228 1.6207 1.6187 1.6168 1.6149 1.6130 1.6112 1.6094 1.6076 1.6060 1.6043 1.60% 1.5694 1.5453 1.5104 1.4844 1.4634 At*. In. Hg P 0.25 0.50 0.75 1.00 1.5 2 4 6 8 10 12 14 16 IS 20 22 24 26 28 30 U>/Sq In. 14.696 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 - 88 90 92 94 96 98 100 150 200 300 400 500 , * Reprinted by perminoa (rom Tkertnodynami* PrvpalitM tf Sltam, by J. IL Keenan sod F. G. Keyee published by Jobs Wiley and 6on, Ino-. 19M edition. TTiermocfynaniics * 27 Table 5 .... Coefficient* A, B, C Appearing in Equations 30, 31, 32, Maximum Values of Corrections Defined by Equations '30 31, 32. Degree of Saturation at Which These Maxima Occur, Maximum Value of Correction .. Defined by Equation 33. Degree of Saturation at Which This Maximum Occurs, . (Standard Ahnotpharic FrestwreJ t BC (F) (ft'/lb.) (Btu/lb.) (Btu/F/lb.) la*. (Btu/lb.) (Btu/F/lb.) Am (Btu/F/lb.) 0.0268 0.00004 0.0004 0.0069 0.00001 0.4925 0.0015 0.3650 0.0042 0.0650 0.00009 0.0010 0.0155 0.00002 0.4878 0.0025 0.3632 0.1439 0.00020 0.0022 0.0332 0.00005 0.4805 0.0040 0.3602 0.3149 0.00042 0.0047 0.0693 0.00009 0.4691 0.0065 0.3557 0.6969 0.00091 0.0099 0.1418 0.00019 0.4511 0-0106 0.3485 1.636 0.00207 0.0207 0.2903 0.00037 0.4213 0.0179 0.3363 192 0 3363 4.608 0.00567 0.0451 0.6180 0.00076 0.3662 0.0333 0.3129 air in relation to saturation, is necessary for locating and An abridgment of the ASHAE Psychrometric Chabt ap describing states on the chart. The arrangement of the pears in Fig. 5. A large sise (24 x 32) chart will be found in ' of curves of constant dry-bulb temperature, wet-bulb ride of the back cover. temperature, volume, relative humidity, and degree of satu The chart is drawn for standard atmospheric pressure. ration, are shown in Fig. 4. Steady flow changes commonly involve pressure drops with Mass and energy balances deal only with net changes be . the flow, but so long as these pressure drops remain a small tween definite states; the detailed history of a change is not fraction of the barometric pressure, no appreciable errors involved. A chart used to facilitate such calculations must need arise from using a constant pressure chart. For many primarily aid in clearly establishing states. Lines drawn on ripsign problems, the use of the standard pressure chart will the chart to connect different states need have no other sig not incur any undue error up to about 2000 ft above sea level. nificance than being loci lines, that is, lines which contain The region above the saturation curve is a two-phase re the two terminal points of a change according to the par gion giving equilibrium states for water in both the liquid ticular overall conditions imposed. Loci tines are commonly and vapor phases. The ordinate of a point in this region is called condition lines for the processes concerned. On the the weight of water in both phases per pound of dry air in ASHAE Chart a condition line is characterised by the ratio the vapor phase, neglecting any dissolved air in the con (.ht - h\i/{Wi - Wx). densed phase. The ordinate at the saturation curve, or the (A) fig. 4 .... Arrangement of Families of Curve* on ASHAE Psychromefrk Chart 28 CHAPTER 3 1959 Guide point at which the break in the isotherm through the point in question occurs, is the weight ol water per pound of dry air in the vapor phase.' Consequently, the difference between the two ordinates -is the weight of condensed moisture per pound of dry air in the vapor phase. * - The shaded -solid-liquid-vapor region at 32 F is an iso thermal three-phase zone, and separates the liquid-vapor zone from the solid-vapor zone. The temperature is 32 F throughout the shaded area. It is possible to obtain two values for the wet-bulb tem perature when this temperature is below 32 F. If the bulb of a thermometer is dipped into water at a temperature slightly above 32 F and held in a stream of air whose wetbulb temperature is below 32 F, the temperature indicated by the thermometer will drop rapidly until a minimum is reached below 32 F. This will be accomplished without the formation of ice'b.n the bulb of the thermometer. After reach ing this minimum temperature, the reading will jump back to 32 F and remain there until the water on the bulb is frozen, after which- it will slowly drop again until equilibrium is reached. The final temperature may be higher or lower t-fran the first minimum reading, or it may be the same depending on the amount of moisture present`in. the mixture. In the absence of reliable data on the wet-bulb' temperature over subcooled-water, the chart' below 32 F, has Seen drawn for the equilibrium condition, that is, the values plotted on the ASHAE chart are for the condition where the minimum tem perature is reached with ice on the bulb of the thermometer. . USE OF TABLE 2 AND THE ASHAE PSYCHROMETRIC CHART The use of Table 2 and the ASHAE Psychrometric Chart in analyzing typical air-conditioning problems is best explained by means of illustrative examples. In each of the following it is to be understood that the processes in question, take place at a constant pressure of 29.921 in. Hg, i.e., standard atmospheric pressure. Example Determine the enthalpy of moist air at 80 F dry-bulb temperature and-0.40 degree of saturation. Solution a: From the data of Table 2 at 80 F, A. = 19.221 Btu per lb of dry air and h,, = 24.47 Btu per lb of diy air. Then A at the specified conditions is 19.221 -f 0.40(24.47) = 29.01 Btu per lb of dry air. Solution b: From the ASHAE Chart. Follow the 80 F drybulb line upward until it intersects the 0.40 degree of satura tion line. From this intersection, follow the line of constant enthalpy to the enthalpy scale and read 29.00 Btu per lb of dry air. Example B: Determine the thermodynamic wet-bulb tem perature of moist air at the conditions of Example 1. Solution a: From the data of Table 2. Applying Equation 8, Ai = 29.01 Btu per lb of dry air (Example 1). As a first approxi mation this is A,* the enthalpy at saturation at the thermo dynamic wet-bulb temperature which is, therefore, approxi mately 63.5 F. W* at 63.5 F is 12.57 X 10~* lb of water vapor per lb of dry air, and IF, is 0.02233 X 0.40 ~ 0.00893 lb of water vapor per lb of dry air. The specific enthalpy of liquid water . at 63.5 F is 31.58 Btu per lb of water. As a second approxima tion, A* - 29.01 + (0.01257 - 0.00893) (31.58) - 29.12 Btu Thermodynamics 29 per lb of dry air. Interpolation in Table 2 gives as the final answer I* -- 63.64 F. ' Solution b: From the ASHAE Chart. At the intersection of the 80 F dry-bulb temperature line and the 0.40 degree of satu ration line, read the thermodynamic wet-buib temperature. Heating of Moist Air at Constant Pressure With out Addition of Moisture Example S: Air initially at 20 F, 0.80 degree of saturation, is heated to 120 F. Find the quantity of beat required to proc ess 20,000 cfm of heated air. .. The process is diagrammatically illustrated in Fig. 6. The energy equation for the process is - 1 G/ii ,-f- i$*Ghi , , v?* " <?,(&* -- kv) - . . Solution a: From the data of Table 2. The initial humidity ratio, which is the same as the final humidity ratio, is 0.80 (0 002152) 0.001722 lb of water vapor per lb of dry air: the initial enthalpy !is 4.804 + 0.80(2.302) 6.646 Btu per lb of dry air: the final degree of saturation is 0.001722/0.08149 = 0.02113; the final enthalpy is 28.841 + 0.02113(90.70) * 30.757 Btu per lb of dry air; tne final volume is 14.611 + 0.02113 (1.905) = 14.651 cu ft per lb of dry air. Since 20,000 cfm of heated air are to be processed, the total quantity of heat re quired is . ..... , . - i? = (20/366/14.651)-X 24.111 32,914 Btu per min. .-Q' -. . .% ' '' ` `Rg. '6 ...Illustration of Process of Example 3 - Solution b: From the ASHAE Chart. The process.is repre sented by the horizontal line 1-2, Fig. 7. The initial enthalpy, at 20 FJary-bulb temperature ana 0.80 degree of saturation, is 6.65 Btu per lb of dry. air. Since the final humidity ratio is the same as the initial humidity ratio, the ratio. (A, -- A,)/ (Wt -- JPi) *=* . The horizontal line 1-2, Fig. 7, then repre sents the condition line for the process, end the final state of the moist air must lie on this line. The final state is located at the point at which the 120 F dry-bulb temperature line crosses the condition line,.and is labeled Point 2 on tbe figure. At this condition the final enthalpy is 30.8 Btu per lb of dry air and the final specific volume is 14.65 cu ft per lb of dry air. Substi tuting these values in the energy equation, ,qt - (20,000/14.65) X (30.8 - 8.65) = 32,950 Btu per min. Cooling of Moist Air at Constant Pressure with Condensation of Water Referring to Fig. 8, moist air cooled from State 1 passes through- successive states along the line, W = W\ -- constant, until the saturation line is intersected. The temperature at this point of intersection is by definition the dew-point tem perature for State-1. . ' Further cooling through successive equilibrium states is accompanied by condensation. :The succession, of states for the total system, moist air.and liquid water, is represented by a continuation of the W W\ line into tbe liquid-vapor region. (Temperatures below 32 F would involve the solia-vapor re gion.) Consider that the final temperature is < . The final enthalpy is then A, ; the liquid water formed is (FF, -- IF,), where Point 3 is at the intersection of the isotherm through 2 and the saturation curve; the final humidity ratio of the moist air is Wt ; and this final moist air has dew-point, wet-bulb, and dry-bulb temperatures all equal to . Example 4-* How much beat must be removed from 20,000 cfm of air at 95 F dry-bulb temperature and 0.50 degree of saturation to cool the air to 70 F, saturated? Solution a: From the data of Table 2. The initial humidity ratio is 0.50(0.03673) = 0.01S37 tb of water vapor per lb of dry air; tbe initial enthalpy is 22.827 + 0.50(40.49) TM 43-072 Btu per lb of dry air; the humidity ratio at saturation at the final temperature is 0.01582 lb of water vapor per lb of dry air; the quantity of liquid formed- is 0.01837 -- 0.01582 = 0-00255 lb of water vapor per lb of dry air; A at 70 F is 38.11 Btu per lb of water; the initial specific volume is 13.980 +- 0.50(0.822) = 14.391 cu ft per lb of ary air. Fig. 9 illustrates the process diagrammatically. The energy equation for the process is Ghi -- Gkt + G(fFt -- fFjJA*, -ji0, = G[A, -- A, -- (IF, -- lF,)A,j = x (43.072 - 34.09 - 0.00255 X 38.07) k 12,350 Btu per min. Solution 6.* From the ASHAE Chart. Two methods may be used to solve the problem by use of the psychrometric chart. The simpler is to use the region to the left of the saturation line (Fig. 8). From Point 1 draw a horizontal line on the chart Rg. 8 .,.. Cooling of Air at Constant Pressure Shown on ASHAE Psychrometric Chart 30 CHAPTER 3 1959 Guide Energy balance for the process, (Jifci + G*A* -- G*A, Mass balance for the water vapor, G,IF, + GtWt = G,VF, Eliminating G* and combining the three equations yields the equation, h, - A, W, - W, G\ A, - A, ~ VP, - IF, " G, (34) until it intersects the constant temperature line in the liquidvapor region corresponding to the final temperature 70 F. This is shown as Point 2 on the diagram. Then, i0* -- G(ht -- A*) The initial enthalpy is 43 Btu per lb of dry air; the initial spe cific volume is 14.4 cu ft per lb of dry air; and the final enthalpy is 34.2 Btu per lb of dry air. The solution of the problem is Example 6: Outdoor air at 0 F dry-bulb temperature and 0.80 degree of saturation is to be mixed adiabatically with recircu lated indoor air at 70 F dry-bulb temperature and 0.20 degree of saturation, in the ratio of one pound of dry air in the former to four in the latter. Find the temperature and degree of satu ration in the resulting mixture. Solution a: From the data of Table,2. The only unknown properties are the humidity ratio Wt and the enthalpy A* of the resulting mixture. These may be determined from Equation 34. Thus, - 20.270 - A, = 0.003164 - IP* 1 A, - 0.668 " Wx -- 0.000630 " 4 i0* " -r-- X (43 - 34.2) = 12,200 Btu per min. from which At = 16.350 and IP* K 0.002657. The enthalpy of the final mixture may also be expressed by Equation 28: The other method is to use an energy balance, ,0, - G)A, - A, - A^(IF, - IF*)) The initial humidity ratio is 0.0183 lb of water vapor per lb of dry air, and the final humidity ratio is 0.0158 lb of water vapor per lb of dry air. Therefore, the beat to be removed is i0* - X (43 - 34.1 - 0.0025 X 38.07) A* = A, 4- j*A Since p by definition is W^/W, , Equation 28 may be rewritten as 16.350 - A. + (0.002657/IF.) X A.. At 56 F the right side of the equation is 16.332, and at 57 F it is 16.582. Interpolation gives as the final dry-bulb temperature of the mixture 56.07 F. At this temperature the humidity ratio at saturation is 0.00960 lb of water vapor per lb of dry air. Therefore, the final degree of saturation is 12,130 Btu per min. Adiabatic Mixing of Two Steady Row Air Streams at Constant Pressure The process is diagrammed in Fig. 10. By applying the prin ciples of the conservation of mass and energy, three equations may be written: Mass balance for the dry air, G, + Gt - G, p - 0.002657/0.00960 - 0.277 jSofuri'on 6; From the ASHAE Chart. Equation 34 indicates that the state point of the resulting mixture lies on a straight t line connecting the state points of the two streams being mixed, and divides this liDe into two segments whose respective lengths are inversely proportional to the rates of dry air flow in the corresponding streams. This is illustrated in Fig. 11. Points 1 and 2 are located and connected by a straight line. Hie state of the final mixture is set so that Gi ft-i 1 Gt Di~i 4 , Thermodynamics Scalinx the distances on the chart, the required solution to Example'5 is 56 F dry-bulb temperature and 0.28 degree of saturation. ` Addition of Moisture to an Adiabatic Stream Consider a stream of moist air flowing adiabatically between two sections, 1 and 2, as in Fig. 12, with moisture addition at the rate - IF,) and the moisture having the enthalpy A. Btu per pound of moisture. An energy balance yields G|Ai + G,(IF* - W,)A. - G,A* (35) Example 6: Liquid water chilled to 40 F is injected into an air stream initially at 95 F dry-bulb temperature and 80 F thermodynamic wet-bulb temperature. At what temperature will saturation be reached? How much water must be evapo rated to reach saturation? Solution a: From the data of Table 2. The solution of Equa tion 35 for A, yields. A, *= Ai 4- (VP* - H\)A. The initial enthalpy of the moist air Ai must be found from Equation 8, A, - A* - (VP* - VPi)A* 22.827 + p40.49 - 43.69 - (0.02233. - 0.03673p) (48.05) from which p = 0.511. Hence, A, - 22.827 4- 0.511(40.49) = 43.52 Btu per lb of dry air. and W, => 0.03673(0.511) -- 0.01877 lb per lb of dry air. The solution of Equation 35 is A, - 43.52 + (IF* - 0.01877)(8-09) " By trial and error, this equation will be satisfied at the tem perature 79.87 F. At this temperature the humidity ratio IP, is 0.02223. The weight of water evaporated is therefore 0.02223 - 0.01877 - 0.00346 lb per lb of dry air. Solution b: From the ASHAE Chart. Solution of Equation 35 for the ratio (A, - A,)/(VP* - VPi) yields . A, -- At , W7^w,~K (36) The slope of the condition line is therefore determined by 31 the enthalpy of the water which is supplied. This slope is es tablished on the chart by connecting the center of the pro tractor on the psychrometric chart with the value of A on the protractor. Draw a line parallel to this reference line through the initial Point 1 (Fig. 13). The second line is the condition line for the process. Since the conditions of the problem re quire the final point to lie on the saturation line, the intersec tion of the condition line with the saturation line gives the desired solution. ' Adiabatic Saturation Adiabatic saturation is the designation given any process in which the state of moist air is changed from some initial un saturated condition to a saturated one without the addition or removal of heat. According to this definition, the addition of moisture to an adiabatic stream may become an adiabatic saturation process. Example 6 is an illustration. A type of adiabatic saturation of further practical interest is the use of continually recirculated spray water in a saturat ing air washer. Here the spray water will ultimately come to the same temperature as the saturated leaving air; this tem perature is, by definition, the thermodynamic wet-bulb tem perature- Hence, adiabatic saturation in this manner will have the final state.point on the saturation curve, with the same thermodynamic wet-bulb temperature as the original state point. In a process such as this, the moist air enthalpy changes very slightly. The moisture added and temperature change may be obtained from the psychrometric chart ss sketched in Fig. 14. Example 7: Moist air at 75 F dry-bulb temperature and 0.60 degree of saturation, is saturated adiabatically with recircu- fig. 10.... Illustration of Mixing of Two Steady Row Streams at Constant Pressure fig. 11 -- . Solution of Example 5 on ASHAE Psychrometrie Chart AT ENTHALPY ft. fig. 12____ Illustration of Addition of Moisture to an Adiabatic Stream fig. 14____ Moisture Added and Temperature Orange 32 CHAPTER 3 1959 Guide lating spray water. Find the amount of water added and the change w enthalpy. * Solution a: From the data of Table 2. As previously stated, the final temperature of the mixture will be the thennodvnamic wet-buib temperature at the initial state. This must first be determined by the method of Example t, and is 65.51 F. At'this temperature the humidity ratio at saturation and enthalpy at saturation are 0.01350 and 30.45, respectively. The humidity ratio at the initial state is 0.60(0.01882) = 0.01129; the initial enthalpy is 0.60(20.59) + 18.018 = 30.372. The weight of water added is therefore 0.01350 - 0-01129 = 0.00221 lb per lb of dry air; the enthalpy change is 30-45 -- 30.372 " 0.078 Btu per lb of ary air. . ' ' Solution b: From the ASHAE Chart. Since the initial and final states have the same thermodynamic wet-bulb tempera ture, the results may be read directly from the chart. Addition of Heat and Water Vapor to an Air Stream in Steady Flow Fig. 15 is a schematic representation of a system operating at constant pressure, where Gi is the rate of flow of dry air, pounds per minute. . Gw is the rate of evaporation of the water, pounds per minute. state may be determined from Equation 8 which inay be re written as . h,, + M..I + - k* The values of these properties are: hf = 35:39; W` = 0.01668: A.* = 39.61; A.., = 90.70; IF., - 0.08149; A., = 28.84. Making the proper substitutions and solving for' degree of saturation, ,* . A .1 -I Rg. 15-------Illustration of Addition of Heat and Water Vapor to an Air Stream in Steody Row . A* is the enthalpy of the liquid water entering, Btu per pound. ' - Q is the rate of heat addition, Btu per minute. An energy balance for the system gives C,h 4- Q + G*A. = Gihi A mass balance gives | G, + GiW, -f <7* = <7, + GlWt (37) or (7, IF, + (?.. - GiWt (38) Combining Equations 37 and 38 and solving for the ratio (At - kD/iWt - Wx), A, - 6, ' Wt -- IF, " ti = 0.0681s -' ' -. The Anal humidity ratio is-therefore 0.0681(0.08149) = 0.005549; the final enthalpy is 28.84 + 0.0681(90.70) = 35.02 Btu per lb dry air. .. The rate of water addition is obtained from Equation 38. _ 20,000 / ` (0.005549 - 0.00172) = 6.32 lb per min. ' The heat supplied is obtained from Equation 37. Q = G,(A, - A,) - GJi* '. . -* . 20,000 - (35.02 - 6.65) - 6.32(28.08) = 46,667 Btu per min. Solution 6: From the ASHAE Chart. Locate the initial and final states oo the chart and connect them with a straight line. Through the reference point on the.chart, draw a line parallel to the line connecting the initial and final state points, the condition line, and read the value of the ratio (A, -- At)/ (IF* -- IF,) as 7500 from the protractor on the chart (Fig. 16). From Equation 39 A* -- Ai Q W- - + fc. - 7500 The rate of water supply was determined in Solution a, but will be found from the chart. It is Example 8: Moist air at 20 F dry-bulb temperature and 0.80 degree of saturation is beated and humidified until it is at 120 F dry-bulb temperature and 71.5 F thermodynamic wet-bulb temperature. Water at 55 F is supplied. 'If-, the air-flow rate is 20,000 cfm at the initial conditions, how much heat is re quired? Solution a: From the data of Table 2. The initial humidity ratio is 0.80(0.002152) = 0.00172; the initial enthalpy is 4.804 + 0-^(2-302) = 6.6456; the initial specific volume Is 12.084 + 0.80(0.042) *= 12.118. The degree of saturation at the final _ 20,000 Gm = (0.0055 - 0.0017) -- 6.28 lb per min Q -- 0.(7500 - A.) . = 6.28(7500 - 23) =-46,900 Btu per min.- .Thermodynamics U. S. STANDARD ATMOSPHERE The definition of the U. S. Standard Atmosphere is im- ud of reference. The bade assumptions in defining the Stand* ard Atmosphere are: . ' 1. There is a linear decrease in temperature T with altitude up to the limit pf the isothermal atmosphere at 35,332 ft. Thus, * 7, - 0.003566 Z (40) 2. The air is dry. .. . ' 3. Air is a perfect gas obeying the laws of Charles and Boyle: PV ~.RT 4. Gravity .is constant .at all altitudes with the standard value. . 6. The temperature of.the isothermal atmosphere is --66 F. Table 6 .... Pressure and Temperature for Altitudes in U. S. Standard Atmosphere . Altitude Feet Z Preuote In. of Hg' F -- t ' , -1,000 -500 0 +500 +1,000 +5,000 10,000 15,000 20,000 25,000 30,000 35,000 40,000 45,000 50,000 31.02 . 30.47 29.921 29.38 28.86 ' . . 24189 20.58 16.88 ' 13.75 11.10 '8.88 7.04 5.54 . 4.36 ' 3.436 . . +62.6 +60.8 +59.0 +57.2 . .+55.4 +41.2 +23.4 +5.5 - -12.3' -30.1 . -47.9 -65.8 -67.0 -67.0-67.0 - Standard values at sea level, which are part of the definition of the Standard Atmosphere, are: Pressure 29.921 in. Hg . Temperature 59 F Absolute Temperature 518.67 F abs Gravity . -32.1740 ft per (sec) (sec) Density 0.076505 lb per cu ft Values of pressure and temperature are listed in Table 6 for altitudes in the standard atmosphere from --1000 to 50,000 ft above sea level. For further explanation, References 9 and 10 should be consulted. LETTER SYMBOLS USED IN CHAPTER 3 n = degree of saturation (decimal), p = density of fluid, pounds per cubic foot. d - relative humidity (decimal). a -- ratio of apparent molecular weight of dry air (28-966) to the molecular weight of water (18.016) = 1.6078. A = coefficient from Table 5 for use in Equation 30 (ob tained from Table 5). B = coefficient to be used in Equation 31 (obtained from Table 5). C = coefficient for use in Equation 32 (obtained from Table 5). 33 / = factor accounting for effect of mixing air and water, dimensionless. G -- flow rate of dry air, pounds per hour. G\ " flow rate of dry air, pounds per minute. Gm = rate of evaporation of water, pounds per minute. H -- enthalpy of the system. H = enthalpy of the flowing medium, Btu per pound of dry air. A = enthalpy of moist air, Btu per pound of dry air. A -- enthalpy correction term to be added above 150-F, - to enthalpy. . A. = specific enthalpy of dry air, Btu per pound. A, = A, -- A. = the difference between the enthalpy of moist . - air at saturation per pound of dry air, and the specific . enthalpy of the dry air itself, Btu per pound of dry air. hg = enthalpy of saturated water vapor, Btu per pound. h, = enthalpy of moist air at saturation per pound of dry air, Btu per pound of dry air. A,* = enthalpy of moist air at saturation at thermodynamic wet-bulb temperature t* Btu per pound of dry air. ' A* = specific enthalpy of condensed water (liquid or solid) at standard pressure, Btu per pound water. Aw* = specific enthalpy of water as added at the thermody- ' ~' narnic wet-bulb temperature I,* Btu per pound of dry air. Awi = enthalpy of liquid water, Btu per pound. A,, = enthalpy of solid water, Btu per pound. KE = kinetic energy, Btu per pound; ' ' &S -- average kinetic energy, Btu per pound. L ~ flow rate of liquid water, pounds per hour. m <= weight of dry air crossing any duct section, pounds per minute. n# = mcfl3 dry air. - ' n, = mols of water vapor at saturation. ' n. = mols of water vapor. ' P = absolute pressure. Pu -- atmospheric pressure, inches Hg. P, = standard atmospheric pressure by definition 29.921 in. Hg. - P, =* saturation pressure of pure water at prevailing tem perature. p = total pressure of a mixture of air and water vapor, pounds per square inch or inches Hg. p = partial pressure of dry air, pounds per square inch or inches Hg. p, -- saturation pressure of pure water vapor, pounds per square inch or inches Hg. p = partial pressure of water vapor in mixture of air and water vapor, pounds per square inch or inches Hg. PE = potential energy, Btu per pound dry air. PE = average potential energy, Btu per pound dry air. Q = total heat added or subtracted, between sections, Btu per minute. q = ratio of energy added (or removed) to water added (or removed), Btu per pound. Also called specific enthalpy of water added. ,qi -- energy added between points 1 and 2. tq = heat added between sections 1 and 2, Btu per pound dry air. R = universal gas constant, 1545 foot-pounds per (Fahren heit degree) (mol). Rt = gas constant for dry air. Aw =' gas constant for water vapor. S -- flow rate of solid water, pounds per hour, s = entropy of moist air per pound of dry air, Btu per (pound) (Fahrenheit degree). 34 CHAPTER 3 1959 Guide LETTER SYMBOLS (Continued) J ** correction to be added to entropy of moist air obtained from Table 2. 8 -- additional correction to be added to entropy because of "mixing entropy" (obtained from Table 5). Correc tion to be added to value of a obtained from Table 2. " specific entropy of dry air, Bin per (pound) (Fahren heit degree, absolute). s* = the difference between the entropy of moist air at satu ration per pound of dry air, and the specific entropy of the dry air itself, Btu per (pound of dry air) (Fahren heit degree, absolute). ' a, =* entropy of moist air at saturation pet pound of dry air, Btu per (pound of dry air) (Fahrenheit degree, abso lute) . s* = specific entropy of condensed water (liquid or solid) . at standard atmospheric pressure, Btu per (pound of water) (Fahrenheit degree, absolute). T ** absolute temperature, Fahrenheit degrees. T, -- standard atmospheric temperature, by definition 518.4 F absolute. . I " temperature, Fahrenheit degrees. t* - thermodynamic wet-bulb temperature, Fahrenheit de grees. . U internal energy of system. U = internal energy. V = volume. V = average velocity, feet per minute. v = volume ol moist air per pound of dry air, cubic feet per pound. & = correction to be added to volume of moist air per pound of dry air, above 150 F. Pc s specific volume of dry air, cubic feet per pound. = p. -- v, the difference between volume of moist air at saturation, per pound of dry air, and the volume of the dry air itself, cubic feet per pound of dry air. v, = volume of moist air at saturation per pound of dry air, cubic feet per pound of dry air. r " total volume, cubic feet. LETTER SYMBOLS (Concluded) W = humidity ratio of moist air, pounds of water per pound of dry air. W, = humidity ratio, at saturation, weight of water vapor per pound of dry air, pound per pound. W.* = humidity ratio corresponding to thermodynamic teet- bulb temperature t * pounds of water per pouod of dry air. - w -- work done by system. . u> " shaft work withdrawn between sections 1 and 2, Btu per pound of air. - ' Z -- elevation above any datum, feet. 2 " average elevation, feet. Subscripts with symbols have following meanings: 1, 2, 3 indicate section of Sow; a -- air, to = water, xel " liquid water, tos = solid water, ** saturation, m = mixture; * indicates that the value is at thermodynamic wet-bulb temperature. REFERENCES 1 J. A. Goff and S. Gratch: The humidity of ratio of moist air at saturation (University of.Pennsylvania, Thermodynamic Research Laboratory Special Report, March 1948). * J. A. Goff: Standardisation of thermodynamic properties of moist air (ASHVE Transactions, Vol. 55, 1949, p. 459). *J. H. Arnold: The theory of the psychrometer (Physics, Vol. 4, 1933). ` J. A. Goff and S. Gratch: Thermodynamic properties of moist air (ASHVE Transactions, Vol. 51, 1945, p. 125). * J. A. Goff and S. Gratch: Low pressure properties of water in the range--160 to 212 F (ASHVE Transactions, Vol. 52, 1946, p. 95). * J. H. Keenan and F. G; Keyes: Thermodynamic Properties of Steam (John Wiley and Sons, New York, 1936). 7 R. Mollier: Kin neues diagramm fur dampfiuftgemische {ZVDI, Vol. 67, September 8, 1923, p. 869). * R. Mollier: Das i-x diagramm fiir dampfiuftgemische (ZVDI, Vol. 73, July 20, 1929, p. 1009). * National Advisory Committee for Aeronautics Technical Report No. 218 (1925). * National Advisory Committee for Aeronautics Technical Report No. 538 (1935). CHAPTER 4 FLUID FLOW Theory of Fluid Flaw, Pressure Loss in Circular Pipes, Pressure Loss in Non-Cirador Pipes; Flow of Compressible Fluids, ideal Flow Through Nozzle or Orifice; Flow Measurement, Head Meters, location of Head Meters and Pressure Taps Pitot Tube, Variable Area Flow Meters HE flow of fluids which is part of the branch of engineer Replacing e by its equal gfgd> (where p is density in pounds Ting science known as fluid mechanics will be discussed weight per cubic foot) and rearranging, Equation 3 becomes here insofar as it applies to the work of engineers in the fields of heating, ventilating, and air conditioning. Probably air is the most frequently handled fluid, but other gases and liquids -- dY* +-dp +dz+-\J du + pdx - Jdq+dW\ - <t (4) 2g p g are often involved. Compressible fluids (gases) and incom In the case of flow through a pipe, no outside work is per pressible fluids (liquids) vary somewhat in behavior, though formed so that dW = 0. Furthermore, in cases where pressure and density changes are small, the gases may be treated as incompressible fluids. J du + p dv * JT ds = J dq + JT ds' (5) THEORY OF FLUID FLOW The following energy equation for one dimensional steady flow processes will serve as a basis for the theory of the flow of fluids. This equation is presented in several ways in various texts, but a suitable form is * Vi* y 7-- + Jui + pjti + Jq + -- ti * = -- + Jtl, + P*t>* + W + -- 2* (1) 2gt g. where V -- velocity, feet per second. g = gravitational acceleration, feet per (second) (sec ond). g, = gravitational conversion factor -- 32.174 (pounds mass per pound force) X ft per (second) (second). J -- mechanical equivalent of heat = 778 foot pounds per Btu. u * internal energy, Btu per pound of fluid. p " pressure per square foot, pounds. v TM specific volume, cubic feet per pound. IF = mechanical work done by the fluid, foot pounds per * pound of fluid. q -- heat transferred to the fluid, Btu per pound of fluid flowing. t = elevation above some arbitrary datum, feet. dt = total change in entropy. dt' -- change in entropy due to internal irreversibility from turbulence and friction. Accordingly, Equation 4 may be written J- iv* + -- + iz + - JT *' - 0* 2go g (6) In cases where there is no internal irreversibility, ds' -- 0, and Equation 6 may be integrated to give where Vf 2g V P* + 2| 2g Pm (7) " proper mean density. This is commonly called the Bernoulli equation, named after the Swiss mathematician and physician who first propounded Subscript 1 refers to the entrance, subscript 2 to the exit. Introducing the enthalpy h, which by definition is u + y> expressed in Btu per pound of fluid. Equation 1 becomes IP- + jh, + 2g, +z *, ~ Tf + *** + v + - g, 2g, gt The equivalent differential form for energy Equation 1 is 36 CHAPTER 4 1959 Guide the theory. ~~ is known as the velocity head, ^ is the pres* Zg p sure head, and z is the elevation head, all in feet of the fluid; the total head, k, is the sum of the other three heads. Fig. 1 shows diagrammntically the relation of the various factors. The pressure at point 2 is lower than at point 1 because of the elevation of point 2 over point 1, and the velocity.at point 2 is lower than at point 1 because of the larger pipe diameter at point 2. If the pipe diameter were the same throughout, the velocity, and consequently the velocity head, woulcl'be'the same at both points, but the higher elevation at point 2 would-still be responsible for a loss in pressure'. The' utility of the equation is evident,-though-it-should'.be re membered that in it the effect* of friction and turbulence are 'negUded;"and 'that Fig.-1 represents- ideal conditions: Tt should also be noted that care must be taken in determining the proper mean density. Accordingly, the Bernoulliequation is applied /most conveniently to incompressible fluids for which density is constant'. - Pressure Loss in Circular Pipes The pressure loss in circular pipes is customarily expressed by the formula: . . Fig. 3------ Relation of Kinematic Viscosity to Temperature of Water ' ' where hi " the loss in head of the fluid under conditions of flow, feet. . I " the length of the pipe, feet. V ** the velocity, feet per second. - . '' 0 = the acceleration due to gravity = 32.174 ft per (sec ond) (second). d = the internal diameter of the pipe, feet. / = a dimensionless friction coefficient. The formula is generally known by the name of Darcy or Fanning, though it seems to have been originated by d'Aubis- son de Voisins in-1834. 1 The factor / is a function of the Reynolds number, .where . Nr. d Vp (9) Nr, Reynolds number. ` ' p = the density, pounds per cubic foot. u TM the absolute viscosity, pounds per foot-second. Both / and the Reynolds number are dimensionless. To aid in computing the Reynolds number, values of the kine- . .. p matic viscosity, are shown as a function of temperature for air in Fig. 2, and for water in Fig. 3. -. Fig. 4 shows the relation between / and the Reynolds number, adapted from a review by Moody.1 The straight line sloping downward at the left of the chart supplies the values of / for laminar flow determined by the formula: / Nr, (10) With laminar flow, the velocity profile is a parabola, having the formula: . Fig. 2------ Relation of Kinematic Viscosity to Temperature of Air U) (11) where r = the radius of the pipe, feet. . h -- distance perpendicularly from the axis of the pipe, feet. . * Accordingly, the maximum velocity occurs at the center of the pipe and is twice the average velocity; the average velocity is found when L = 0.707 r. It is worth noting that roughness of the pipe wall has no effect on the loss in head for laminar flow. ... .. Between values of the Reynolds number of 2000 and 4000, 1 Superior Dumbers refer to the rrfa- s oi the end of chapter. Fluid^FJoVv' ' there is^an^ unstable region where the flow changes from laminar'td turbulent, or vice versa. The actual value is im possible' of. prediction for any condition* of flow, though in general it may be said that the prevailing type of flow per sists into the unstable region; however, once a change starts, it proceeds very rapidly. When the flow is turbulent, the velocity profile is essentially parabolic over four-fifths of the pipe diameter, but near the pipe walls, the effect of friction becomes evident, and in the boundary layer at the pipe wall the flow is laminar. Fig. 5 compares the velocity profiles for three different Reynolds numbers, but for the same average velocity. The lower curve in the turbulent region in Fig. 4 represents the relation of / to the Reynolds number for smooth pipe, such as drawn brass tubing or glass tubing. The effect of roughness on /, an effect which is considerable in turbulent flow, is open to some conjecture; artificially roughened pipes, for instance, give results at variance with actual tests. The curves above the smooth pipe curve of Fig. 4 represent a summary of tests on rough pipe, each of them identified by a .value of e/d, with e signifying the absolute roughness-in feet. Values of e for different pipes are given in Table 1. To find the friction loss for any pipe, follow the curve with 37 Table 1 . ...Values of e for Different.Kinds of Pipe Type of Pipe Commercial steel or wrought iron.............. Riveted steel.................................................. . 0.000005 0.00015 0.0004 0.0005 0.00085 0.0006 to 0.003 0.001 to 0.01 0.003 to 0.03 the proper value of e/d, to the pertinent value of Nr, , and from this point proceed horizontally to left margin, to^find the value off for use in Equation 8. ' The curves in Fig. 4 may be approximated very closely by the empirical formula:1 / - 0.0055 + ^20,000 ? + (12) Equation 8 is applicable to all liquids, and to gases when REYNOLDS NUMSER, Note.- The straight Horn of left ihows ratoo* of Friction fccter for lomfncr flow. Reprinted by permission from ASM JYaiuoctioos. . Fig. 4...\Relation Between Friction Factor and Reynolds Number ' 38 CHAPTER 4 1959 Guide fig. 5.... Comparison of Velocity Profiles for 3 Different Reynolds Numbers but for Same Average Velocity tiie pressure loss is less than 10 percent of the initial pressure. When the loss in head is high, the formula to be used for gases is Pi1 - pf _ flVi* . Pi* pd Pifi which may be arranged to give the loss in pressure, (13) "--"['-/`IS] (14) Pressure Loss in Non-Circular Pipes The formulas for friction loss in pipes are based on the use of pipes of circular cross-section. The same formulas may be extended to noncircular sections, by suitable modification. In the basic formula. Equation 8, the internal diameter d is to be replaced by the hydraulic diameter defined by the equation: j_ 4 X area of cross-section wetted perimeter of cross-section For example, in a rectangular duct, 1 ft by 2 ft, the cross section area is 2 sq ft, and the perimeter 6 ft. Then the hy draulic diameter will be dfl = (4 x 2)/6 = 1)$ ft. In tile case of a round pipe, 4 X rd*/4 dar d *d 06) In computing the Reynolds number, and from that- the friction factor, the hydraulic diameter is not to be used. A better approximate procedure is to replace the length in the Reynolds number by the shortest dimension plus one-fourth of the hydraulic diameter. Thus, in a duct of dimension a x b where a < b, Nr, , for the purposes of calculating fric tion factors, is tfa. - (o + 0.25dm)Vp/n (17) This value of Nr, may be used in Equation 10 for laminar flow, and in Equation 12 or Fig. 4 for turbulent flow. The error in the approximation is somewhat greater for laminar than for turbulent flow. In the former case, the relative error may be as much as 10 percent, while in the latter it almost always is less than 3 percent. ROW OF COMPRESSIBLE RUIDS In tiie flow of compressible fluids, the large density varia tions make it impracticable to use the Bernoulli equation, (Equation 7). In certain special cases, however, the exact equations for compressible flow may be stated. If flow occurs with no friction or other interna! irreversibility Equation 6 becomes -1 dV +d-v2 - 0 2? p If, in addition, the flow is adiabatic, (18) p~* - pur* so that Equation 18 becomes ' (is) Zg or by integration, + p, p11* (20) This extension to compressible flow of Bernoulli's equation reduces to the more familiar form if the pressure change is small. The ratio of specific heats, 4, is used extensively in fluid dynamics; values of 4 for various gases are given in Table 2. It is convenient in the analysis of compressible flow to in troduce the velocity of propagation of pressure impulses or, more familiarly, the sonic velocity, a. For perfect gases this is given by the equation; a* - kgp/p = kgRT Accordingly, Equation 21 may be written (22) or, by rearrangement, which permits the calculation of the ratio of pressures at entrance and exit of the steady flow device--pipe, orifice, or nozzle. From Equations 19 anrf 22 it follows that ' * \P1/ - (V,1 - Vi*) -f at* - a,* - 0 (27) The ratio of flow velocity to sonic velocity is known as the Mach number, M - V/a This parameter is particularly useful in compressible flow analysis. In general, if M 0.1 the flow may be considered I 3 Fluid-Flow' to bo incompressible- This is generally true in heating and ventilating air ducts. In terms of the Mach number (28) and (29) 39 Table 2____Ratio of Specific Heat at Constant Pressure to Specific Heat at Constant Volume for Compressible Fluids Coapnnibh Fluid ftofio k = e,/c. 1.66 Carbon dioxide, methane, natural gas, super heated steam, moist steam down to a quality 1.34 Sulfur dioxide, ethylene, acetylene....................... 1.24 to L26 The quantity, P* - P ^1 + (30) is called the stagnation pressure, and gives a measure of pres sure energy. For incompressible flow where _ p + i ,,V' - p + q ig (31) so that / * -T SVSRsFlM- ---- (38) If the initial velocity is sufficiently small, M? will be negligible so that , = (32) and is the dynamic pressure. Atotal head tube, measures stagnation pressure directly. From Equation 29 it follows that for frictionless, adiabatic flow pf" pi* (33) This represents another extension of the Bernoulli equation to compressible flow. Friction will cause a loss in pressure energy. Ideal Flow through Nozzle or Orifice The majority of tow-head measuring systems depend upon a correlation between pressure drop, area, and quantity of flow. The basic formulas may be stated on the assumption that the flow is frictioDless arid adiabatic. Designating the main stream by station 1, and flow at some measuring re striction by station 2, the flow in pounds per second is w " PiAiVy = piAtVt or, in terms of Mach number, to = t y/kgptpt According to Equation 29 (34) (35) (39) If this is computed and the figures are plotted, the eurved line (partly solid and partly broken) of Fig. 6 is found. The maximum value of may be computed by differentiating Pi . to with respect to p* and equating the result to zero. This operation produces the equation: . (40) For air, with 4 = 1.40, -- = 0.53. Pi Actually, the broken part of the curve is not attained for (36) fig. 6.... Relation of Flow of Gas to Pressure Drop in a Converging Tube 40 CHAPTER 4 1959 Guide where 0 = Dt/Dt. The quantity 1 fy/1 -- (3A is the velocity of approach factor as generally used, with 8 being the ratio of the throat or orifice diameter to the pipe diameter. Since Ap/p, is small and tiie mass flow is ' to = V2ppAp (47) (Coefficient diown at a function of Reynoldi Number and kaiio, A/At J From Reference 4. Used by permtuioo. Fig. 7.... Dimensions and Flow Coefficient for Standard Square-edged Orifice with Corner Taps or Annular Slits the flow in the nozzle. If the ratio of p* to p, is decreased from unity, the mass rate of discharge, as well as the volume, in creases from zero to a maximum, as shown by the solid sec tion of the curve in Fig. 6; thereafter, as pt/pi is decreased further, the discharge is constant, as indicated by the hori zontal line. The value of p, at the maximum point is called the critical pressure, or pe, and it is seen that pe is approxi mately 53 percent of pi when air is flowing. .To find the velocity at the critical pressure, it is assumed that the upstream velocity Pi is so small as to be negligible. Using, the subscript c. to indicate conditions at the critical point, from Equation 29 or W-7] m Substituting the critical pressure ratio from Equation 40 it follows that Mt - 1 (43) or that the velocity at the throat is equal to the local sonic velocity. In developing the working equations for orifices and noz zles, it is customary to start with the incompressible form of tiie flow Equation 38. In this case both Af, and Af, are small quantities, p, = pi, and (pi -- p,)/p*. = Ap/p, is small. Retaining only first order terms, it follows from Equation 35 that /. Af,- At : Mi At (44) so that ' / * --1 - .1 t* 1 (45) Vl - AMMO1." Vl -- ff* The volume flow is then 1 y/2g&p/r> = A, Vl-F Vl-i V2gk, (48) FLOW MEASUREMENT The measurement of quantity of flow of fluids is generally accomplished either by making observations on the change of state due to flow system configuration, such as the pres sure drop across a metering orifice, or by the displacement of some device, such as a rotating vane system. The .selection of the metering system will be determined by the type of fluid, the precision of measurement desired, the cost of equip ment and installation, the range of flow quantity, the ease of maintenance, and the method of observation and record ing. . .. Fluid meters may be classified as'follows: (1) Head Meters (Pressure Sensitive), which may.be of Venturi, flow nozzle, orifice plate, or Pitot tube types; (2) Area Meters, which may be of gate, tapered lube, or tapered plug types; (3) Force Meters, which may be of vane, propeUor, or turbine types; (4) Quantity Meters, which may be of weighing tank, recipro cating piston, or geared impeller types. , ... Rate meters are generally of the first three groups, al though rates are obtainable from timed observations of quantity meters. Similar quantity measurements can be ob tained by suitable integration of rate meter indications. Head Meters '- The head meter is of sufficient flexibility so that almost any type of flow measurement can be handled. For this reason, standard and reference measurements are usually made in this way. With proper care, extreme precision can be ob tained. Also, an inexpensive installation can be made to give moderate precision. In general, a head meter requires fairly competent installation and maintenance to give satisfactory service. Among the types of head meters, the Venturi has the ad vantage of having a low pressure loss, but requires consider able length of space. The orifice plate reduces the required length to a minimum at the cost of considerable pressure drop.. The flow nozzle represents a compromise, but must be cali brated individually, or made with extreme care from standard specifications, to obtain a good precision of measurement. Standard configurations, for representative orifice plates and flow nozzles, are shown in Figs. 7 and 8, respectively. Ad ditional specifications are given in References 2, 3, and 4 at end of chapter. The measurement-of flow in head meters is dependent 41 From Referwo 3. Usad bjr ponaitdoo of ASMS. Fig. 8 .;.. Dimensions for International Standards Association Flow Nozzle upon observations of a static pressure difference between two parts of-the system. Standard locations for these static pres sure measurements are illustrated in figs 8 and 16. In general, there exists a reduction in area, either by a smooth contour as in the case of a Venturi or flow nozzle, or by a vena con tracts following an orifice. In either case, the flow will be given by a suitable modification of Equations 47 and 48. Adding a correction term, these become Fig. 9____Flow Coefficients, K, for Square-edged Orifice Plates and Flange Taps in Smooth Pipe to - . = \/2gpAp Vl -- <r (49) and Q _ -^== V2|R (50) In all casra, At refers to the minimum area of the Venturi, nozzle, or orifice. Hie correction factor C is introduced to account for any loss due to departure from isentropic flow, and for any deviation between the downstream measured pressure and the actual pressure at the minimum section. Since these corrections are usually dependent on configura tion, as described by the ratio of upstream to minimum area At/At, it is often convenient to introduce a combined flow coefficient, K which is so that ' C Vl -0* (51) w KAt>/2gp&p (52) and Q - KA, vm, (53) The coefficients K and C will be determined by the area ratio Ai/At, or by the diameter ratio Dt/Dt and the Reynolds number. Extensive data are available from various sources.1,4 figs. 9, 10, 11, 12 show representative values of K based on Ng., the Reynolds number, and the ratio of diameter of the orifice or nozzle throat to pipe diameter. - In any specific application, numerical values for areas, densities, and pressure units can be substituted in Equations 52 and 53 to obtain compact working formulas. In planning flow measurements, standard flow meter dimensions and standard pressure tap locations should preferably be used so From Fig. 36d of ffeferanca 3. Rg. 10.... Flow Coefficients, K, for Square-edged Orifice Plates and Radius Taps in Smooth Pipe Rg. 11....Flow Coefficients, K, for Square-edged Orifice Plates and Vena Contracto Taps, in Smooth Pipe 42 CHAPTER 4 1959 Guide From Reference 3. Uwct by permission of ASA4E. Rg. 12....Row Coefficient for International Standards Association Flow Nozzle Shown in Rg. 8 as a Function of Area Ratio iDt/Dj* and the Reynolds Number Nue that published flow coefficients can be used for accurate de termination of flow rates. In measuring the flow of compressible fluids, the approxi mate Equations 52 nd 53 must be corrected for density variations. The need for such correction is evident by com paring Equations 35 and 38 with Equation 47. Introducing a multiplicative correction factor 6>. the equation for flow with no loss becomes: "* " y/T^d* -_p^ ^ By comparison with Equation 35, . ,/k P' M't{(11 - y) r 2 p,i (Wpxjp-pt) - i From Equations 34 and 35, WiVAf** - 0Wpi>m Hence, by Equation 38 for a small value of Mt, - (55) (56) Fig. 13.... Relation of Expansion Factor, <, for Nozzles to Diameter Ratio and Pressure loss for Air and Other Diatomic Gases While may be used for smooth nozzles and Venturi tubes, it is necessary in the case of orifices, where the de parture from ideal flow is significant, to replace 6 by an empirical factor Y obtained by the equation Y - 1 - (0.4! + 0.35<!) ~ P'/t^ (61) When this correction is used, the flow will be given by the equation ' 1 KAtY V2ffp,(p - pi) J (rh) (pi/p){t-)a - 1 (pi/pt) -- 1 1 - 0*(pjpi) From Equations 37 and 56, if Mi is not too large, (57) iife-1)681-'**11- 2(i - 2)0flAf,* (58) so that, approximately, (59) where to the same degree of approximation from Equation 36 *Pi Values of 0 are also given by Figs. 13 and 14. (60) Rg. 14.... Relation of Expansion Factor, <f>, for Nozzles to Diameter Ratio and Pressure loss for Steam, Carbon Dioxide and Natural Gas FluidFlow 43 Location of Head Meters and Pressure Taps In the ingfadlntinTi of Venturis, orifices, and nozzles, care muk be t*kn in regard to upstream and downstream flow conditions. Recommended practice, with reference to fittings and valves, is shown by Fig. 15. If these conditions cannot be met, some flexibility is possible by introducing straighten ing vanes, as described more fully in (References 2 and 5. The static pressure difference across the head meter is a & 7 > & D D/D. measured by suitably located static pressure taps. For orifices, the different sets of pressure taps are called flange taps, radius taps, vena contracts taps, and pipe or full-flow taps. The relative locations of the first three of these are shown in Figi 16. The flow coefficients in Figs. 9, 10, and 11 apply only to measurements made with these pressure tap locations. The need for applying suitable coefficients to measurements ob tained by means of the different taps, is indicated by the curve of change, in pressure of the flowing fluid, shown in the lower part of Fig. 16. Pipe taps are located 2M pipe diameters up stream' and 8 pipe diameters downstream (both distances being measured from the upstream face of the orifice plate) so that pressures are measured before the orifice plate has bad any effect on the flow, and after the recovery in pressure has been completed. The use of pipe or full-flow taps has been limited to the metering of natural fuel gas in certain areas. As they are not suited to use in heating and ventilating work, no data for them are given in this chapter. Still another type of pressure tap, the comer tap, is used in European practice. Pressures are taken from recesses in - the flange connected to annular slits in the comers formed by LOO* FIANCE TAPS i-v ' lUTOOSoj VENA CONTRACT* TAPS (SEE FICURE 17) . Hr ---- ^030,- RADIUS TAPS pj Fig. 16 .... Relative Location of Range, - Radius and Vena Contracto Taps Rg. 15____Minimum Conditions to be Observed When Installing Orifices and Nozzles Between Fittings and Valves the pipe wall and the orifice plate. Coefficients for these taps have been adopted by the International Standards Association, but are not used commercially in America. ' It will be noted that the location of the downstream pres-, sure tap of the vena contract* arrangement is variable. Vena contracto is the terra applied to the minimum cross-section of the* jet from the orifice, where the static pressure is at a minimum. Its location, and the location of the downstream vena contracts tap, vary with the ratio of orifice to pipe di ameter, and with rate of flow, as shown in Fig. 17; the tap is generally located in accordance with the mean curve' in the'figure. '' . Similar precautions are required when using flow nozzles and Venturi tubes. In many cases, these will be supplied 44 CHAPTER 4 1959 Guide % N ok I \> fc* i, JL sss s \ /\ i o at q.4 04 a* i.o u i u PIPE OUKCTCPS Fig. 17.... Location of Vena Confracta in Relation to Ratio of Orifice to Pipe Diameter and to Rote of Flow Variable Area Flow Meters For permanent installations where high precision, niwwiness, and ease of operation are important, the variable area flow meter has proved very satisfactory. Its most frequent use is in measurement of liquids or gases in small diameter pipes. For ducts or pipes over 6 in. in diameter, the expense of this meter may not be warranted. In large systems, how ever, the meter might be placed in a by-pass line and used in conjunction with an orifice. In its most common form, the variable area meter, Fig. 18, consists essentially of a float which is free to move vertically in a transparent tapered tube. The fluid to be metered enters at the narrow bottom end of the tube and moves upward, passing at some point through the annulus formed between the float and inside wall of the tube. At any particular rate of flow, the float assumes a definite position in the tube, its ready for installation. In such cases, the manufacturer's instructions should be followed with care in order to avoid serious errors. Further information on such systems is given in References 2, 3, and 5. Pitot Tube In certain cases, such as in rectangular ducts, it is impracti cable to use standard orifices, and consequently, either a specially designed orifice must be calibrated, or an inde pendent flow device must be used. In either case, the Pitot tube is useful. It consists essentially-of an inner bent tube with its open end pointing upstream so as to measure total pressure, and an outer tube having small holes on the side for communicating static pressure to a manometer. (See Fig. 3, Chapter 44). The difference in'liquid level in the manometer will be proportional to the square of the velocity, for incom pressible flow, so that in general - ..... v - Vw, (63) For compressible flow, the differential head is to be divided by the correction Fc from Equation 64, where Ft - 1 + %M* + (64) (65) In the use of a Pitot tube system, care is required in ob taining correct total and static pressures. The total pressure tube must be smoothly constructed, and should point di rectly upstream. The static pressure tap must be located so that local flow interferences will not reduce the value. In any case, it is better to obtain an independent calibration, or use a specially designed and manufactured probe. A number of such Pitot tube probes are available, and can be used without calibration. In using Pitot tubes to obtain flow rates, it is necessary to make a traverse of the pipe and thereby to obtain one of the profiles of Fig. 5. In rectangular ducts or near valves or fit tings, a disturbed flow pattern would be obtained, and there fore, in such cases, a fairly complete survey should be made. The flow in such cases will be computed from the average of the local velocities, as obtained by Equation 63. Fig. 18 .... Schematic Diagram of Variable Area Flow Meter location being indicated by means of a calibrated scale on the tube. The position of the float is established by a balance between the fluid pressure forces across the annulus and the weight of the float itself. The buoyant force which must support the float, V/(pf -- p), is balanced by the pressure difference acting on the cross-section area of the float, A/Ap, where pf, Af, oJt are, respectively, the float density, float cross-section area, and float volume. Accordingly, the difference in head across the annulus is given by Ap _ o,(p, - p) p Afp (66) The volume flow follows from Equation 53 as Q " KAt\/2gvf{pf -- p)/pAt and the mas3 flow as - (67) w " pQ " KA*\/2gvf(pf -- p) p/Af (68) The flow for any selected fluid is, accordingly, very nearly proportional to the area, so that a convenient calibration of RyidCFlow the tube may be obtained. The behavior of the flow coefficient, K has been investigated4 and the action of the flow meter as just outlined, experimentally ouiimmeu. The Sow coefficient variation for any float must be known in order to use the meter for different fluids. Some developments have been carried on in the design of the float to reduce the variation of the flow coefficient with Reynolds number, and also with regard to float materials, to reduce the dependence of mass flow calibration on fluid density. This type of flow meter is usually furnished in standard sixes calibrated for specific fluids by the manufacturer. The compactness, reliability, and ease of installation are particu larly advantageous when many measurements of essentially oamp. type are to be made. LETTER SYMBOLS USED IN CHAPTER 4 0 -- ratio, throat or orifice diameter to pipe diameter. >i = absolute viscosity, pounds per foot second. p/p " kinematic viscosity, square feet per second. p = density of flowing fluid, pounds per cubic foot. pm = proper mean density, pounds per cubic foot. = density of water at 80 F (62.37 lb per cubic foot). pi = density of float id variable area meters. 4 = expansion factor for nozzles. - a -- velocity of sound, feet per second. A -- cross-sectional area of flow, square feet. C =* correction factor (coefficient of discharge) for flow through orifice, nozzle or Venturi. .. e, -- specific heat of gas at constant pressure. c, = specific beat of gas at constant volume. D diameter of fluid stream, feet, d = internal diameter of pipe, feet, ds " hydraulic diameter, feet. e = absolute roughness of pipe surface, feet. Ft " correction factor for differential head in compressible flow. / = dimensionless friction coefficient. g = gravitational acceleration, feet per (second) (second). gt =* gravitational conversion factor ~ 32.174 (pounds mftAft per pound force) X feet per (second) (secood). h -- enthalpy, Btu per pound of fluid. h/ -- loss of head, feet of fluid. A, ** total head, feet of fluid. J -- mechanical equivalent of heat = 778 foot pounds per Btu. K -- flow coefficient (correction factor), including velocity of approach correction factor, for flow through orifice, nozzle or Venturi. k -- ratio of specific heat at constant pressure to specific heat at constant volume. L -- perpendicular distance from axis of pipe, feet. I = length of pipe, feet. 45 U = Mach number. - A'g, -- Reynolds number. p = pressure, pounds per square foot. - p# -- stagnation pressure, pounds per square foot. p, = critical pressure. Q a discharge rate, cubic feet per second. q = heat transferred to the fluid per pound of fluid flowing, Btu. R = gas constant, r " radius of pipe, feet. * = entropy of fluid in Btu per (pound) (Fahrenheit de gree). T = temperature, absolute, Fahrenheit degrees, u = internal energy, Btu per pound of fluid. V -- velocity, feet per second. Vt = critical velocity, feet per second. v a specific volume, cubic feet per pound. W a mechanical work per pound of fluid flowing, foot pounds. to a mftM flow of gas, pounds per secood. Y a expansion factor (correcting for expansion of gas under reduced down-stream pressure). t a elevation above some arbitrary datum, feet. REFERENCES 1 L. F. Moody: Friction factors for pipe flow (ASME Trans actions, Vol. 66, 1944, p. 671, with discussion p. 678); also An approximate formula for pipe friction factors (Mechanical Engineering, Vol. 69, 1947, p. 1005). * American Society of Mechanical Engineers: Fluid Meters, Their Theory and Application (1937, 4th ed.). * American Society of Mechanical Engineers: Flow Measure ment, Power Test Codes, 1949, Part 5, Chapter 4. 4 National Advisory Committee for Aeronautics, NACA Tech. Mem. 952, 1940: Standards for Discharge Measurement (Translation of German Industrial Standard, 1932). * American Gas Association, Natural Gas Department: Gas Measurement Committee Report No. 2, 1948. * E. M. Schoenborn Jr. and A- P- Colburn: The flow mecha nism and performance of the rotameter (American Institute of Chemical Engineers Transactions, Vol. 35, 1939, p. 359). BIBLIOGRAPHY E. F. Obert: Thermodynamics (McGraw-Hill Book Co., 1948) . N. A. Hall: Thermodynamics of Fluid Plow (Prentice Hall, 1951). R. A. Dodge and M. J. Thompson: Fluid Mechanics (McGraw-Hill Book Co., 1937). R. C. Binder: Fluid Mechanics (Prentice Hall, 2nd Ed., 1949) . P. P. Ewald, H. Poschl and L. Praodtl: The Physics of Solids and Fluids (Blackie, 1936). Emory Kemler: A study of the data on the flow of fluids in 46 CHAPTER 4 1959 Guide pipes (Hydraulic Paper HYD-55-2 ASMS Transactions, Vol. 55, No. 10, pp. 23-32, 1933). R. J. S. Pigott: The flow of fluids in closed conduits {Me chanical Engineering, Vol. 55, 1933, pp. 497-501 and p. 515). American Society of Mechanical Engineers: Fluid Meters, Their Selection and Installation (1933). ' A. D. MacLean: The Orifice Meter for Measurement of Flow of Gases and Liquids (Pittsburgh Equitable Meter Co., 1938). Edward S. Cole: Pitot tube practice (ASME Transactions, Vol. 57, 1935, pp. 281-294; with discussion Vol. 58, 1936, pp. 145-156). Edward S. Cole and E. Shaw Cole: Pitot tubes in large pipes {ASME Transactions, Vol. 61, 1939, pp. 465-473, with dis cussion pp. 473-475). C. W. Hubbard: Investigation of errors of pitot Cubes {ASME Transactions, Vol. 61, 1939, pp. 477-497, with discus sion pp. 497-506). R. E. Sprenkle: Piping arrangements for acceptable Sowmeter accuracy (ASME Transactions, Vol. 67, 1945,. pp. 345 357, with discussion pp. 357-360). CHAPTER 5 HEAT TRANSFER - Conduction Connection, Radiation; Equations for Conduction, Convection, Radiation, and Combined Convection and Radiation; Heat-Flow Resistance, in Series and Parallel; Practical Heat Transfer Problems; Periodic and Transient Heat Flow EAT is the form of energy that is transferred by vir in small tubes, or with viscous liquids such as heavy oil (low H tue of an existing temperature difference. The tem Reynolds numbers), the entire flow may be laminar. In these perature difference is the potential which causes the translatter cases there is no transition or eddy region. fer, the latter in turn being resisted by the thermal properties When the fluid currents are produced by sources external of the material combined in a single term known as the re to the heat transfer region, as for example by a pump, the sistance. Energy exchange associated with evaporation, described solid to fluid heat transfer is termed forced con condensation, etc., is treated elsewhere such as in the sec vection. In contrast, if the fluid currents are generated in tion Cooling Tower Theory in Chapter 40. The objectives ternally, as a result of non-homogeneous densities arising of this chapter are to: from the temperature variations, the heat transfer is termed 1. Describe the mechanisms and present the rate equations for the different modes of heat transfer. 2. Illustrate the application of the basic concepts to steadystate problems (temperature independent of time or a cyclic variable thereof) by means of several typical solutions of heat transfer systems. 3. Present concise summaries of available methods of analy sis for transient and periodic beat transfer problems. Further applications to specific systems-will be found throughout The Guide. free convection. In the conduction and convection mechanisms, the trans fer of heat is associated with matter. For radiant heat trans fer, however, a change in energy form takes place, from in ternal energy at the source to electromagnetic energy for transmission, then back to internal energy at the receiver. The rate of heat transfer, corresponding to the three transfer mechanisms previously described, may be expressed by three rate equations. These are similar to Ohm's Law for electrical flow, the current flow through a resistance CONDUCTION, CONVECTION, AND RADIATION being proportional to the potential. The convection and radi ation flow rate expressions may be approximated by a po Thermal conduction is the term applied to the mechanism of heat transfer whereby the molecules of higher kinetic energy transmit part of their energy to adjacent molecules of lower kinetic energy by direct molecular action. Since the temperature is proportional to the average kinetic energy tential (temperature difference) and a resistance in order that heat transfer calculations may be effected more con veniently and rapidly. Thermal Conduction Equation' of the molecules, thermal transfer will occur in the direction of decreasing temperature. The motion of the molecules is random; there is no net material flow associated with the conduction mechanism. In the case of flowing fluids, ther mal conduction is significant-in the region very close to a solid boundary or wall, where the flow is laminar and parallel with the wall surface, and where practically no cross cur rents exist in the direction of the heat transfer across the Equation 1 states symbolically that the thermal conduc tion per unit transfer area normal to the flow, q/A, Btu per (hour) (square foot), is proportional to the tempera ture gradient (dt)/{dL), Fahrenheit degrees per foot. The proportionality factor is termed the thermal conductivity, k, Btu per (hour) (square foot) (Fahrenheit degree per foot of thickness). solid fluid boundary. In solid bodies the significant mecha nism of heat transfer is always thermal conduction. In contrast to the thermal conduction mechanism, ther mal connection involves energy transfer by eddy mixing and The minus sign on the right side of the equation is intro diffusion1 in addition to conduction. This is shown sche duced to indicate positive transfer in the direction of de matically in Fig. 1 which exhibits transfer from a pipe wall creasing temperature. Fig. 2 shows the physical significance at surface temperature 4 to a colder fluid at a bulk tempera of the indicated quantities. ture tf . (Bulk temperature is that which would be attained It should be emphasised that the thermal conductivity if the fluid stream were drawn off at a certain section and used should be expressed in consistent units; either using mixed. It is therefore somewhat higher than the lowest the inch or foot throughout. temperature in the stream.) In the laminar sublayer, im Expressions of conductivity used in the heating field are mediately adjacent to the wall, the heat transfer occurs by usually inconsistent in this sense, in that it is customary to thermal conduction; in the transition region, which is called refer to the conductivity per square foot but for one inch of the buffer layer, eddy mixing as well as conduction effects thickness. This custom has been adopted for the reason that are significant; in the eddy or turbulent region the major wall thicknesses are usually expressed in inches, whereas fraction of the transfer occurs by eddy mixing. if expressed in feet, decimal or fractional thicknesses would In most commercial equipment the main body of the fluid result. When dealing with flat walls, no complication is in is in turbulent flow, and the laminar film exists at the solid volved in using the inconsistent expression of conductivity. walls only, as shown in Fig. 1. In cases of low-velocity flow However, where curved or spherical walls are concerned, 47 48 CHAPTER 5 1959 Guide <xrnRiHp:mh1f complication is involved. Therefore, in this discussion the consistent units of conductivity expressed in Btu per (hour) {square /oof) {Fahrenheit degrees -per one foot thickness) are used throughout. Conductivity values obtained from Chapter 9 or Table 1 in this chapter, must therefore be converted for use in the calculations of this chapter by dividing by It. As an example, the conductivity of brick listed as 5.0 in Table 4 of Chapter 9, becomes 0.42 when used in the calculations of this chapter. Also, it should be emphasized that in order to make the calculations and applications con sistent in this chapter, all dimensions of thickness must be expressed in feet. Fig. 1 .... Thermal Convection Conditions Thermal Convection Equation ' J - < - 1,) (2) This rate equation states that the thermal convection per unit transfer area (q/A), Btu per (hour) (square foot) is proportional to the temperature difference (t. -- </) which is the temperature of the surface less that of the fluid. The particular fluid temperature to use for a given system will be noted under the discussion of that system. The propor tionality factor is termed the unit thermal convective con ductance (sometimes called the film coefficient for convec tion), A., Btu per (hour) (square foot) (Fahrenheit degree). Fig. 1 shows the conditions associated with convection. The heat transmission by free or natural convection for objects surrounded by air can be conveniently expressed as in Equation 3: where q -- -- heat transmission by convection, Btu per (square foot) (hour). Table 1 .... Approximate Unit Thermal Conductivities* Conductivity, k = Bfo per (hr) (tq A) (F dmg per in.) Material k Material k Brass (70 - 30).. Castilron.............. Copper................... Glass...................... 720.0 Soil..................... 336.0 Steel, mild. - - 2640.0 Water,liquid.. 3.6-7.32 2.4-12.0 312.0 4.08 * Thermal conductivities depend to some extent on temperature. The above msfzutadee are approximate only. Refer to Chapter 0, aad Reference i for ad ditional data. . C -- a constant depending upon the shape of the sur face. D = diameter of pipe or circular duct or height of ver tical wall, inches. (Effect of diameter or height becomes constant at 24 in.) T,, -- average of wall surface and surrounding air tem perature, Fahrenheit degrees absolute. t, -- tf * temperature excess between wall surface and sur rounding air, Fahrenheit degrees. For horizontal cylinders, the value of C -- 1.02 has been well established by various investigations. For vertical plates, the value of C -- 1.39 has been fairly well established. Suggested values1 of C for horizontal plates warmer than the surrounding air are 1.79 when facing upward, and 0.89 when facing downward. Problems in either forced convection or natural convec tion may be solved by the simple first-power equation if the convection coefficient is expressed as a unit conductance: q = KA(h - M (4) where ' q = heat transmission by convection, Btu per hour. A = surface area, square feet. temperature difference between the surface and the fluid, Fahrenheit degrees. Ac B unit convective conductance, from Table 2, Btu per (square foot) (hour) (Fahrenheit degree tem perature difference). . Fig. 2 .... Thermal Conduction in a Rat Slab Thermal Radiation Equation The relation given by Equation 5 is applicable to systems in which radiant exchange takes place between the surfaces of solids, as schematically shown in Fig. 3. . qr - cA,FaFs{TS - TV) (5) Gaseous and luminous radiation are not considered in this discussion. Equation 5 states that the net radiation per unit transfer area of surface 1, qr/A Btu per. (hour) (square foot), which sees surface 2 through a non-absorbing medium, is proportional to tire difference of the fourth powers of the absolute surface temperatures (TV -- TV). The proportion ality factor (vFAFg) may be conveniently separated into three parts (excepting in some problems involving inter reflections, where it is not possible to divide the product (FaFm) into separate terms): a -- the Stefan-Boltzmann radiation constant -- 1730 X 10-12 Btu per (hour) (square foot) (Fahrenheit degree abso lute temperature to the fourth power). HeatTransfer 49 c Table 2-------Approximate Unit Conductances for Thermal Convection for Several Flow Systems Cxp/msted m Coairentea* Empirical fana -' Systtm Hoot.Tramf*r Equation* cad lit limits of Application Farad Convction uL&j Ref. 3 1--X-- 1 p Longitudinal flow in V y 1 a circular cylinder.*1 . V - 0.0225 (jip) General Equation (^y " where % > 4 AD and ^--) > 2200 2 Ref. 3 Same as Case 1 .b Equation for Air '. <? . / DO\ h* -- 5.4 X lO^fT*/)*-* where x > 4.4D and 1 -- j > 2200 3 Ref. 3 Same as Case 1> h, = 13.5(1/)-" Equation for.lAquid Water (32-400 F) where x > 4.4D and > 2200 4 Ref. 4 single cylinder. ` General Equation htD Y'Am'V* --j~ * 0.28 1 -- \ ( -- J dg where 1000 < -- < 50,000 5 Ref. 4 Same as Case 4. 6 Ref. 4 Same as Case 4. Equation for Air (u )-! 0.211(7V)- w* n/; where 1000 < -- < 50,000 M Equation for Liquid Water (32-400 F) A(aHra,,) = 34.0(1/)-** t where 1000 > -- > 50,000 7 Ref. 3 "= J . Flow along a flat plate, j///?//////////' General Equation (Turbulent Flow) V ' 0 0296 (?)'(t)' " "*"* (?) > 500'000 --and A. 1.25ACC S Ref. 3 Same as Case 7. Equation for Air (Turbulent Flow) ,, h,, - 0.51 (TV)* where > 500,000 --and h*(mrtTam) 1.25A,, 9 Ref. 3 Same as Case 7. General Equation (Laminar Flow) For (^) < 500,000 and - 2h,, 10 Ref. 3 Same as Case 7. Equation for Air (Laminar Flow) h,, - 0.0562(7-,)* ` For < 500,000 50 CHAPTER 5 1959 Guide- Table 2____ Approximate Unit Conductances for Thermal Convection for Several Flow Systems (Conceded) Coi Heal frontier Equation* and lit Uaiit of Application Free Convection* 11 Ref. $ y&jyJ Free convection past a heated h. - 0.271 horizontal cylinder. Equation for Air * (0 * where 10* < Not < 10* 12 Ref. 6 ii 1 1 W Free convection past a single vertical surface. ht - 0.354 ht - 0.420 (ff Equation for Air (j'j where 10* < Nar < 10* where 10* < Nar < 101* 13 Ref. 5 // L-- t --J Free convection past a heated horizontal surface (face up). hc - 0.478 Equation for Air where 10* < NGt < 10* 14 Ref. 5 f---- l ---- horizontal surface (face down). Equation for Air k. - 0.239 ()- (") where 10' < No. < HP Noaendofvre and Dimensoa* for Table 2 c, = heat capacity at constant pressure, Btu per (pound) (Fahrenheit degree). D = cylinder diameter, feet. / * subscript denoting film. - g = body force per unit mass, feet per hour per hour. (For static system on earth, q = 32.2 X 3600* feet per hour per hour.) G * 3600 uw> = mass flow per unit cross-sectional area normal to flow, pounds per (hour) (square foot of flow cross-section). Na, = Grashof modulus, dimensionless (Nor " Dtf>iQAlg/pi). h, = average unit thermal convective conductance from the leading edge of surface to the position x, Btu per (hour) (square foot) (Fahrenheit degree). *= local unit thermal convective conductance, at the position z from the leading edge of surface, Btu per (hour) (square foot) (Fahrenheit degree). k = thermal conductivity, Btu per (hour) (square foot) (Fahrenheit degree per foot thickness). i = a dimension of the system, feet. m -- a subscript denoting mean. P si pressure, atmospheres. Pm * pressure (atmospheric), atmospheres. t " temperature, Fahrenheit. T -- temperature, Fahrenheit, absolute. * u -- fluid velocity, feet per second. V -- volume, cubic feet, x b a dimension of the system, feet. fi -- coefficient of cubical expansion (0 " for perfect gases 0 = \/T. At " difference between wall and fluid temperatures, Fahrenheit degrees. p = fluid viscosity, pounds per (hour) (foot). p -- density, pounds per cubic foot, co = infinity, referring the quantity to a point not directly affected by the phenomenon in question. Fluid properties rixxild be ercJuAled At the arithmetic mean fluid temperature, 1/ -- (W/o*. + divided by 1. . ___ . b Thaw expraaions ue suitable approximation* to longitudinal flow is other than right areolar cylinders, provided the hydraulic diameter a employee as ue cos- duit dimension parameter. For non<irciilar goes aaetiom, the hydraulic diameter is equal to (our times the cross-sectional area divided by the wetted perimeter. _ For low rates ef heat transfer by (res ooBvectkm the exponent decreases towards scro, and for higher rates, increases towards 0.33. The above equations employing an exponent equal to 0-2$ are applicable in the intermediate range indicated. ' ____________ = the geometrical factor which is dimensionless and 1. This factor accounts for the shape and relative position of the two surfaces. The value of Pa TM 1 may be used in the cases of large parallel planes, long concentric cylinders or smaller bodies in large enclosures. -- the emi8sivity factor which is also dimensionless and S 1. This factor accounts for the absorption and emission characteristics of the surfaces for the radiation which exists. Emissivities or absorptivities (f) for many com mon surfaces, are given in Table 3. The value of Ft for large parallel planes, long concentric cylinders, or large enclosed bodies is 1 + (1/e* + l/* -- 1). The radiation under black-body conditions, or for an emissivity of 1.0, is given in Table 47 for cold surfaces as low as --39 F to warmer surfaces as high as 139 F. Some net radiation exchange solutions for several common radia tion systems are given in Table 5. There are several methods by which the geometrical Heat Transfer 51 factor Fa can be determined. One method involves the use of a mechanical geometrical integrator (Reference 8). Photo graphic and other methods are given in References 9 and 10. Equivalent Conductance for Radiation Although Equation 5 is a suitable equation for describing radiant exchange, it is not convenient for computations where other modes of energy transfer are operative. For such cases, it is convenient to define an equivalent conductance for radiation -by the equation: ' q, - M - I*) (6) The conductance hr thus defined is a function of the shapeemissivity factor, as well as the temperatures of the radia tor and receiver. Fig. 7 shows a plot of tile equivalent con ductance for two black bodice (i.e., with emissivities equal to unity) which exchange energy only with one another. Combined Convection and Radiation It should be noted that the previous equations and-tables give the heat transfer by convection and by radiation com puted separately. In many practical cases it is desirable to treat convection and radiation as a single combined process, using a first-power equation: qrc - kroAd, - (,) (7) where Qrc is the total heat flow due to radiation and convec tion, in Btu per hour. Values of h,e, the surface or film con ductance for combined radiation and convection, are given in Table 3 and Fig. 4 of Chapter 9. Complete tables for the combined heat transfer of steam and hot water radiators, pipes, coverings, etc., will be found in the appropriate chap ters. HEAT-ROW RESISTANCE In most of the steady-state heat transfer problems en countered in air conditioning applications, more than one of the heat transfer mechanisms are effective, and the ther mal-current flows through several resistances in series or in parallel. In using the resistance concept, the calculations involved are analogous to the application of Ohm'6 Law in electricity, viz., the heat flow or thermal current is directly proportional to the thermal potential or temperature differ ence, and inversely proportional to the thermal resistance: tical analyses of heat transfer in building walls, in fin-tube coils, and in pipe coverings, are usually computed by this method. The same resistance analysis may be applied to complicated steady-state conduction problems. Table 6 gives the. resistances in six common cases of steady-state conduc tion. A complete analysis by the resistance method is well il lustrated by considering the heat transfer from the air out side to the cold water inside of an insulated pipe. The tem perature gradients and the nature of the resistance analysis are indicated by the two sketches of Fig. 8. Since air is sensibly transparent to radiation, there will be some heat transfer by both radiation and convection to the outer insulation surface. The mechanisms act in parallel on the air side. The total transfer by radiation and convection then passes through the insulating layer and the pipe wall by thermal conduction, and thence by convection and radia tion into main cold water streams. (Radiation is not signifi cant on the water side as liquids are sensibly opaque to radi ation, although water transmits energy in the visible re gion.) The contact resistance between the insulation and the pipe wall is presumed to be equal to zero. - Referring to Fig. 8, the heat transferred for a given length N of pipe, qtt, Btu per hour, may be thought of as flowing through the parallel resistances R, and R*, associated with the insulation surface radiation' and convection transfer. Then the flow is through the resistance offered to thermal conduction by the insulation, Rt, through the pipe wall resistance, Rt, and into the water stream through the con vection resistance, Ri. Note the analogy to the direct cur rent electrical circuit problem. A temperature (potential) drop is required to overcome these resistances to the flow of thermal current. The total resistance to heat transfer, Rt, (hour) (Fahrenheit degrees) per Btu, is the summation of the individual resistances: Rt ** Ri + Rt -4* R + Ri (11) where the resultant parallel resistance R is obtained from Provided the individual resistances may be evaluated, the total resistance can be obtained from thin relation. Then the heat transfer for the length of pipe (N, ft) can be es tablished by the relation Following the electrical analogy, when there is a thermal current flowing through several resistances in scries, the re sistances are additive: Rt = R, + R, + R, + - + R. (9) qn (Btu per hour) = -- ^ (13) Rt For a unit length of the pipe the heat transfer rate is Btu per (hour) (foot) - ^ ^ (14) Similarly, conductance is the reciprocal of resistance, and for heat flow through several resistances in parallel, the conductances are additive: Cr (10) Practical Heat Transfer Problems The use of these relations for resistance and conductance makes possible the solution of many practical heat transfer problems. As discussed iQ Chapters 9, 23, and 32, the prac Fig. 3 .... Radiation Between Surfaces 52 CHAPTER 5 1959 Guide Clan Table 3 .... Radiation Factors or Enussrvities, * For the determination of factor Fg in Equation 3 Fraction of Blade-Body Radiation At 50-100 F At 1000F' ALiOtfJhity for Solar Radiation 1 2A 3 4 5 6 7 '8 9 id A small hole in a large box, sphere, furnace, or enclosure........................ 0.97 to 0.99 0.97 to 0.99 Black Don-metallic surfaces such as asphalt, carbon, slate, paint, paper. 0.90 to 0.98 0.90 to 0.98 Red brick and tile, concrete and stone, rusty steel and iron, dark paints (red, brown, green, etc.)........................ ;......................................................... Yellow and buff brick and stone, firebrick, fire clay................................... White or light-cream brick, tile, paint or paper, plaster, whitewash... Window glass............................................................................................................. Bright aluminum paint; gilt or bronze paint................................................. Dull brass,'copper, or aluminum; galvanized steel; polished iron.......... Polished brass, copper, monel metal.................................................................. Highly polished aluminum, tin plate, nickel, chromium................. .......... 0.85 to 0.95 0.85 to 0.95 0.85 to 0.95 0.90 to 0.95 0.40 to 0.60. 0.20 to 0.30 0.02 to 0.05 0.02 to 0.04 0.75 to 0.90 0.70 to 0.85 0.60 to 0.75 0.30, to 0.50 0.05 to 0.15 0.05.to 0.10 * EmiMTitM of other "iii mey be found in Reference 4. * ReQecte about 8 percent. 0.97 to 0.99 0.85 to 0.98 0.65 to 0.80 0.50 to 0.70 0.30 to 0.50 Transparent* 0.30 to 0.50 0.40'to 0.65 0.30 to 0.50 0.10 to 0.40 - The temperature drop, At, through an individual resistance may then be calculated from the relation: . At = Rq,, (15) where R is the resistance in question. . The problem is now reduced to one of evaluating the in dividual resistances of the system. This entails suitable manipulation of the rate Equations i, 2, and 5 to produce expressions of the form: . dicate the magnitudes of the thermal conductivities, k, to be employed in the expressions of Table 6, after dividing k by 12. . : i . The solution applicable to the problem depicted in Fig. 8, for tiie calculation of Ri and Rz,' is-Case 2 in Table 6. Thus for a I-ft length of 2 in. nominal size pipe (I. D. = 2.067 in., 0. D. =* 2.375 in.) insulated with 1 in. of material hav ing a conductivity of 0.025: . ' ' ' / 1.188 . . - lo- , 033......................... . ' R* ------- ----r " 8.5 X 10- (hr) (F deg) per Btu. 2x X 26 X 1 ' . where q'is the heat transfer rate, and At is the potential drop or temperature difference through the resistance RTable 6 lists such solutions for six different conduction sys tems. Table 4 in Chapter 9 and Table 1 of this chapter in 1 188 R " 2, X 0.025 X I - 3 9 <hr) P" ^ The convection resistances to heat transfer from the pipe Toap F Dog -30 -20 -10 0 0 10 20 30 40 50 60 70 80 90 100 110 120 130 * FrnmftT- Table A .... Heat Transmission by Ratiiation for Black-Body Conditions* Exproaed in flfu per (tquorw ffj (hear) 0 -1 -2 -3 -4 --5 --6 . -7 -8 -9 59.3 65.2 71.4 78.0 ' 68.7 64.7 70.8 77.4 58.2 64.1 70.1 76.7 57.7 63.5 69.5 76.0 57.2 62.9 68.9 75.4 56.7 62.3 68.3 74.7 56.2 . 61.7 67.7 74.0 , 55.7 ` 61.1 67.1 73.4 . 55.2 60.5 66.4 72.7 54.7 59.9 65.8 72.1 0 + 1 +2 +3 +4 +5 +6 +7 +8 +9 78.0 85.0 92.4 100 109 118 127 137 148 159 170 183 196 211 78.7 85.7 93.3 101 110 119 128 138 149 160 171.'' 184. 197 212 79.4 86.5 94.0 102 111 120 129 139 150 161 173 185 199 214 80.1 87.2 94.8 103 112 121 130 140 151 162 174 187 200 215 80.8 88.0 95.6 104 112 122 131 142 152 163 175 188 201 217' 81.5 88.7 96.4 105 113 123 132 143 153 164 176 189 203 218 ' 82.2 89.4 97.2 105 114 123 133 144 154 166 178 191 204 220 82.9 90.2 98.0 106 115 .124 134 145 155 167 179 192 206 221 83.6 90.9 98.8 107 116 125 135 146 156 168 180 193 207 222 84.3 91.7 99.6 108 117 126 136 147 157 169 182 195 209 224 Twn mill of wnm SS F to surface at --15 F for effective eroissrvity of 0-85 (103 -- 63.3} 0.94 * J7.7 Blu per (square foot) (hour). Heat Transfer 53 > l| p2 Sydea Two infinite parallel planes. Table '5 ... Net Radiation Solutions ' Solution -J + - -1 .. - SemeHu Considering interrefiections. (Refer ence 5) |* 2j 1I1 One radiation shield ^2 between two infinite parallel planes. I-G) 1 . 'm` v*: Considering interrefiections. (Refer . ence 5) 1 I 111 |tl2|3l.|.|.|.|ru n radiation shields between two infinite parallel planes. x-rh(i). 'w(!)s 'Considering ence 5) is tfie net radiation exchange withoui' the shields. ' i interrefiections. (Refer ' s--s. Two concentric spheres ( ij\2 or two infinitely long \S~^J cylinders. Considering interrefiections and diffuse surfaces. (Reference 5) /C\4*2 Two areas dAi and dA* d^o, Fa(Tx* - TV) Surface diffuse, neglecting intcrreflection. (Reference 5) s--n. 1 R v ) 12 1 Tube of infinite length parallel to an infinite wall. 2rRN ~ (2) e,t*`r<7'4 " where N is the length of cylinder from which qT is exchanged. Neglecting interrefiections. (Reference 5) {-- r~ j Surfaces are perfect radiators. r Surface element dA and roc- tangle above and parallel to it, with one corner of rectangle contained in normal to dA. See Fig. 4 ' (Reference 4) fSv. Surfaces are perfect radiators. Adjacent rectangles in perpen- dieular planes. * See Fig. 5 ' (Reference 4) I| -I I |1 Surfaces are perfect radiators. Opposed parallel rectangles and discs of equalsise. See Fig. 6 , (Reference 4) wall to the cold water, Ri, and from the air to the surface of . the insulating material, Rc, are dependent on the flow conditions prevailing at these surfaces, and on the thermal properties of the fluids. These resistances are also directly dependent upon the temperature distribution, and for this reason it is necessary first to guess, on the basis of the prob lem statement, a temperature distribution upon-which to base the initial calculations. Since the values of hc for heat transfer between water and pipe walls are relatively high in this temperature range, it is logical to assume only a small temperature difference between the temperature of the fluid body and the temperature of the pipe wall. For the purpose of an initial guess, this temperature difference will be as sumed to be 2 deg. On the other hand, A* for heat transfer from air to a body is relatively small, and a higher tempera ture difference would be expected between these masses. The value initially assumed here will be 20 deg.Tn summary, the temperature distribution in the system is assumed as follows: *' Fluid temperature = 34 F. Inner pipe wall temperature: = 36 F. Outer insulation surface temperature 9 100 F. Ambient air temperature " 120 F. With these assumptions and the problem statement, it is now possible to calculate values for the convective resist ances. If it is found in the ultimate solution of the problem that the temperature distribution is different from that as sumed, it will then be necessary to repeat the solution pro cedure. If reference now be made to Table 2, it is found that Case 3 of this table is a system similar to that encountered in the 54 CHAPTER 5 1959 Guide Table 6 .... Solutions for Some Steady-State Thermal Conduction Problems*-b 0jcpf Oftf for the fhmtanc* It Entwing into the Equation q - At/R (Btu per hour) Flat wail or curved wall if curvature is small {wall thick ness less than 0.1 of inside diameter). UTJ Radial flow through a right circular cylinder. lentcyfindo, otlenetaN f^rtl r*J The buried cylinder. logy - (See footnote e). log. cosh-' 1 +^ 2xiJV 2vkAr For - ^ 3, satisfactory approximation is: Radial flow in a hollow sphere. 2rkN 2rkN ^ 1^ r< r The straight fin or rod heated at one end. Finned surface of area HB. - (see footnotes d and e). h,p tanh mL For ml > 2.3, tanh mL * 1 m -- y/Kp/kA A = conduction cross-eection area, - p " perimeter of cross-section A. h, = unit conductance to the surroundings from the f surface. k = thermal conductivity fin material. At -- wall temperature--ambient temperature. (s + 4) *(! tanh ml + * ) HB iy ** Surface are*. HB At defined as in Case 5 above. a TSq to bo employed l& tiaKMlutWBi in: |s|t]i of n, t.r fwi; units of 4 " Btu per (boux) (aquAro foot) (Pahnobat degree for one foot thiehuot); unit* of 4, Btu per (boor) (aquare foot) (Fabieabcat decree); unite ot area, A -- aquare feet. b Tbe thermal conductivity, 4. in these solution* should be takes at the tnnp material temperaturr. E Lac. * " 2-303 loci* * . S This expression can also be employed aa an appraximataoo for tapered fioa or of annular fins by employing average magnitudes of A and p. * ta&b is tbe byperbolie tangent. . . Heat Transfer 55 convection between the water and the pipe wall. The equa tion for this case is the following: K- (17) where u. -- 5 fps 2-067 ,, _ 13.9 X 6.9 X 3.62 494 Btu per (hr) (sq ft) (F deg). This heat transfer rate is through the inner surface of the pipe and it is, therefore, this area that determines the re sistance R, . A = rD * 0.542 sq ft per unit length of pipe. and therefore RADIATION BETWEEN ADJACENT RECTAMCLE* IN PER...nniiu [< DIMENSION RATIO' Z V- RATIO (LENGTH OF UNIQUE SIDE OP THAT RECTANGLE ON WHOSE AREA THE HEAT TRANSFER *U4Equation is based) + (length of common S<)*V WWTCM Z-RATIO (LENGTH Of UNIQUE SIDE OF other rectangle? + (length of common Sle-Z/* IN SKETCH Fig. 5 .... Geometrical Factor F for Direct Radiation Be tween Adjacent Rectangles in Perpendicular Planes* M 494 X 0.542 Rt = 3.73 X 10"* (hr) (F deg) per Btu. Case 11 of Table 2 fits the conditions of the problem if only free convection heating of the pipe is assumed. The equation in this case is as follows: ht - 0.271 ft)"" (18) At = 20 F D = 0.364 ft P = P. = one atmosphere therefore, / 20 Y h, = 0.271 I ) \0-364/ h. = 0.737' Btu per (hr) (sq ft) (F deg) Using the surface arreea of thile insulation, the value of the resistance per unit lesnnggth is tdetermined. /4.375\ A 12 / - 1.14 sq ft Fig. 6 .... Geometrical Factor F for Direct Radiation Between Opposed Parallel Rectangle and Discs of Equal Size* H. C. HoMel, Radiant beat transmission, (Mechanical Sntineerinf, July 1930. pp. 700 to 703). M 0.737 X 1.14 Re 1.19 (hr) (F deg) per Btu. This result may not be deemed conservative inasmuch as the expression is for still air. If, however, the air is not still, but flows at approximately 5 mph or 7 fps, the heat transfer equation for forced convection would apply. This equation is Case 5 of Table 2. 0.211(2/)* ,.M*Z>* (19) 56 CHAPTER 5 1959 Guide the resistance just calculated, can be computed with the aid of Fig. 7. The pipe wall, assumed at 100 F sees the surround ings st 120 F. If these two temperatures arc 7,'ith Fig. 7, a value for is determined directly. - 1.4 Btu per (hr) (F deg) (sq ft). rap* The angle factor, PA , is unity, and for an estimated surface emissivity of 0.9S (see Table 3), Pg -- 0.95. Therefore, hr - 1.4 FaPm -1.4 X 1 X 0.95 K -- 1.33 Btu per (hr) (F deg) (sq ft) and the radiation resistance, R,, is then the following: Fig. 7.... Equivalent Conductance for Radiation Between Two Black Bodies Exchanging Energy Only with One Another 100 + 120 T/ -------------------+ 460 = S70 R&nkine (F absolute) um ** 7 fpa 9 0.0694 lb per cu ft D - 0.364 ft 0.211(670)*<7 X 0-0694)*-* heit " (0.364)** and 2.73 Btu per (hr) (sq ft) (F deg) (Forced Convection) - ^ ^ * , J4 ft. -- 0.321 (hr) (F deg) per Btu. The radiation resistance, Rr, which acts in parallel with Fig. 8 .... Heat Transfer Conditions m an Insulated Cold Water Line hrA 1-33 X 1.14 -- 0.659 (hr) (F deg) per Btu. The resultant resistance of fi and Rr acting in parallel (see Fig. 8) can now be evaluated as: ft. " oBi + 0^5 " *M Btu (hr) (F dee) R* R* -- 0.216 (hr) (F deg) per Btu. The overall resistance, RT, surroundings to cold water, is the sum of ft, + ft, + ft, + R* -- 4.12 (hr) (F deg) per Btu for. 1-ft length of pipe. Note that the controlling re sistances are Rt and ft, and that neglect of both fii and fit would not significantly influence the total resistance, fir . On the basis of this resistance calculation, the heat trans fer from the surroundings to the cold water may be evalu ated as: ' qrr ^ U - t, = 120-34 N " fir 4.12 20.8 Btu per (hr) (ft) or about 0.175 tons of refrigeration per 100 ft of pipe. Since the calculation is based on a 1-ft pipe length. q,, -- 20.8 Btu per hr. . The temperature drops through the various resistances are now readily evaluated by Equation 16 as: . At = qR ' t, -- l,|.(air to insulation surface) - qRt - 20.8 X 0.216 - 4.49 F deg fi -- tgt (through the insulation) - qRt - 20-8 X 3.9 -= 81.2 F deg ttt -- l.i (through the pipe wall) qRt - 20.8 X 8.5 X 10"* = 0-018 F deg Id -- 1/ (pipe wall to cold water) = ?ft, = 20.8 X 3-73 X 10-* - 0.078 F deg This solution was obtained on the temperature distribu tion assumptions initially made. It is apparent that a better solution could be obtained if the whole problem were re iterated using the temperature distribution just calculated. PERIODIC AND TRANSIENT HEAT FLOW The foregoing data and examples dealt with steady-state heat transfer (not varying with time). In most practical Heat Transfer 57 heat transfer problems the heat flow depends upon time. Such of*"** can usually be divided into two classes: periodic and transient. Periodic heat transfer repeats periodically in time. Transient heat transfer exhibits no periodicity. Graphical, analytical, and numerical methods are avail able for solving transient or periodic heat flow prob lem* o-u.u.u Graphical and numerical methods are the most versatile, And can be applied with minimum mathe matical training. A huge number of analytical solutions for the case of heat conduction in variously shaped solids are available in the literature. Table 7 gives a summary of the cases reported find tabulated. Many more analytical solutions are available in the form of. infinite series,ull11,8 but are not tabulated. Certain complex cases may be treated by combining the simple analytical solutions as discussed in Reference 17. (See also Reference 20.) Frequently, transient heat flow problems in one dimension have boundary conditions which make the problem difficult the .temperature of the x plane at a time Ad later will be in accordance with this nomenclature, the temperature at any plane x and time 8 + Ad is given as (30, which may be interpreted as follows. The temperature of the slab at any plane, x, and any time, 8, is equal to the average temperature of the two adjacent planes obtained at the time (8 -- Ad). The time interval Ad is determined by the equation AS* At 2a (21) Omitting the graphical construction at the slab boundaries, reference to Fig. 9 demonstrates the graphical method by means of which the temperature at each plane is deter mined at successive intervals of time in accordance with Equation 20. For the problem stated, the boundary condition at the insulated surface is specified by the equation ^-0 dx and at the uninsulated face by the equation Mr. -- T) = --<t -- dx ' In terms of finite differences these two equations (employing nomenclature established by Fig. 9) become Fig. 9 .... Example of a Graphical Solution to a Problem in Transient Heat Conduction to treat analytically. In such cases, recourse may be made to a graphical method of solution sometimes called the Schmidt method.*'l0*l,,UJ* This method will be briefly outlined for the case of transient heat flow in a slab insulated on one face, and suddenly exposed on the other face through a fixed thermal resistance to a higher temperature. The technique is general, however, and methods may be devised for any boundary conditions,S,H and also, for one dimen sional (radial) heat flow in spheres and cylinders.*1 ** Consider the slab to be divided, as shown in Fig. 9, by n equidistant planes parallel to the slab surface and a dis tance Ax apart. Let the temperature of the slab at any plane and any time (5) be denoted by TV,*. Then the temperature of the slab at the two adjacent planes at the same time will be denoted as and In a similar manner -------------- = 0 or 7V =" Tg at x -- L Ax and or h(T,, 7V> k (Te - Ta) at Ax T, - TV k/h Ta - Ta Ax 0 The details of the graphical construction are best obtained by inspection of Fig. 9. Note that the line (0,0,00 used to initiate the graphical construction, is the only one drawn to the slab boundary A'. The numbered points indicate tem peratures at the sub-slab boundaries at 1,2,3, etc., time in tervals (Ad) after the slab is exposed to the high tempera ture. For transient heat flow in two dimensions, and also, for steady-state conduction, numerical methods of solution are available in the literature.These numerical meth ods are applicable to three-dimensional problems, although the calculations involved normally become too tedious for most applications of the method. An additional technique of solution for one- and two-dimensional problems in transient conduction results from the analogy of electrical resistance- capacitance networks to thermal systems.14 - For two-dimensional problems in steady state conduction, additional techniques of solution are found in flux plotting,6'18 and in the use of a potential tank.*'18 These methods are of 58 CHAPTER 5 1959 Guide Table 7 .... Analytical Solutions for Heat Conduction in Variously Shaped Solids Shop* of Soft* Boundary CandiHon* Dafa Avaifcifafa m Graph* Semi-infinite. -------------- - ts~ Semi-infinite with fluid at free surface- Surface temperature suddenly changed. Temperature distribution in solid as a function of time. References: (4) p. 37; (5) p. V-28; (10) p. 254; (13) p. 46. Heat flow from surface as a function of time. ' References: (10) pp. 256, 267; (13) p. 47. A steady flow of beat is suddenly applied to the surface. Temperature distribution as a function of time. Reference: (10) p. 257. The surface temperature has been varying sinusoidally with time for a long time. Temperature distribution as a function of time. Reference: (10) p. 296. Heat flow from surface as a function of time. Reference: (10) p. 296. The temperature of the fluid in contact with the surface has a sudden change. (The surface conductance is constant.) Temperature distribution as a function of time. . References: (4) p. 37; (5) pp. V-45,46,47. e Slab. The temperature of the fluid in contact with the surface has been varying sinus oidally with time for a long time. (The surface conductance is constant.) Temperature distribution as a function of time. Reference: (10) p. 298- Heat flow from the surface as a function of time. Reference: (10) p. 298. The temperatures h and it are suddenly changed from the initial uniform slab temperature to a new temperature. (The case where the surface on one side is in sulated is treated by taking the case of a slab of twice the given thickness since the midplane has no heat flow due to symmetry.)- Temperature distribution as a function of time. References: (5) p. V-12; (10) p. 265. The temperatures h and It suddenly begin to increase as linear functions of time. The slab is initially at uniform tempera ture. (The case where one surface is insulated against heat flow is treated as noted above.) Temperature distribution as a function of time. Reference: (10) p. 268. The temperature at both surfaces has been varying sinusoidally for a long time. Temperature distribution as a function of time. Reference: (10) p. 300. Heat flow from the surface. Reference: (10) p. 303. Heat Transfer .' 59 Table 7 .... Analytical Solutions for Heat Conduction in Variotisly Shaped Solids (Continued) Shop* oi Sohd Boundary Condition* Data Arodabh Si Graph* Slab immersed in a fluid with constant conductance between fluid and slab surface. ' The temperature of the fluid is suddenly changed from the initial uniform slab temperature. (If one surface is insulated against heat flow, see above.) Temperature distribution as a function of time. : References: (4) pp. 32, 33, 34, 35; (5) pp. V-9, 10,35,42; (10) pp. 274, 284; (13) p. 106. X rt . *c, K lw 1 Cylinder of infinite axial dimension. Heat flow from the surface as a function of time. References: (5) p. V-10; (10) p. 274; (13) p. 107. The temperature of the fluid at one surface varies as a periodic function of time while the temperature of the fluid at the other surface is constant. The conduct ances need not be the same on both sides. (The variations in temperature are expressible as a Fourier series.) Temperature distribution as a function of time. Reference 14. Heat flow at the surface as a function of time. Reference 14. The surface temperature is suddenly changed from the initial (uniform) tem perature. Temperature distribution as a function of time- Reference: (10) p. 265. Heat flow from surface as a function of time. Multiply temperature difference between surface and fluid by surface conduct ance. The surface temperature suddenly begins to increase linearly with time. Temperature distribution as a function of time. Reference: (10) p. 269. Cylinder of infinite axial dimension im mersed in a fluid. The surrounding fluid suddenly changes from the initial (uniform) temperature of the cylinder. Temperature distribution as a function of time. References: (4) p. 36; (5) pp. V-16, V-35, V-43, V-48; (10) pp. 278, 286; (15). Heat Sow from the surface as a function of time. References: (5) p. V-16; (10) p. 278. The temperature of the surrounding fluid changes sinusoidally. Temperature distribution as a function of time. Reference: (5) p. VI-34. Heat flow from the surface as a function of time. Reference: (5) p. VI-36. Sphere. The temperature of the surface is suddenly changed from the initial uniform tem perature. Temperature distribution as a function of time. References: (5) p. V-23; (10) pp. 264,265. The temperature at the surface suddenly begins tochange as a linear function of time. Temperature distribution as a function of time. Reference: (10) p. 269. 60 CHAPTER 5 1959 Guide Table 7 .... Analytical Solutions for Heat Conduction in Variously Shaped Solids (Conceded) Shape of Solid Boundary Condition! Data Arailabl* in Graphs Sphere immersed in fluid. The temperature of the surrounding fluid suddenly changes from the initial uni form sphere temperature. Temperature distribution as a function of time. References: (4) p. 36; (5) pp. V-21, V-35, V-44; (10) pp. 281, 282. Heat flow as a function of time. References: (5) p. V-21; (10) p. 281, Rectangular bar of infinite length. Any of the above noted boundary condi-' tions for a stab. . Temperature distribution as a function of time. , Combine solutions as indicated in Refs. 16 and 17. Parallelopiped (rectangular). Any of the above noted boundary condi tions for a slab. Temperature distribution as a function of time. Combine solutions as indicated in Refs. 16 and 17. Cylinder of finite length. Any of the boundary conditions given above for a cylinder and a slab. Temperature distribution as a function of time. Combine solutions as indicated in Refs. 16 and 17. Hollow cylinder of infinite exterior ra dius. The temperature of tbe surface suddenly changes from the initial (uniform) tem perature. Temperature distribution as a function of time. . >; Combine solutions as'indicated in Refs. 16 and 17. ;, Heat flow at the surface as a function of time. Reference: (10) p. 267. most direct use in problems in which the boundaries of the two-dimensional shape are made up of isothermal and ad iabatic surfaces. . REFERBJCES 1 T. K. Sherwood: Absorption and Extraction (McGraw-Hill Book Co., New York, 1937). .f Griffith and Davis: The Transmission of Heat by Radiation and Convection (Department of Scientific and Industrial Re search Special Report No. 9, His Majesty's Stationery Office, London, 1933). * A. P. Colburn: A method of correlating forced convection heat transfer data and a comparison with fluid friction (Ameri can Institute of Chemical Engineers Transactions, VoJ. 29. 1933. p. 174). * W. H. McAdams: Heat Transmission (McGraw-Hill Book Co., New York). * L. M. K. Boelter, V. H. Cherry, H. A. Johnson, and R. C. Martinelli: Heat Transfer Notes (University of California Press, Berkeley, 1946). ' V. S. Touloukian, G. A. Hawkins, and Max Jakob: Heat transfer by free convection from heated vertical surfaces (ASMS Transactions, 1948, p. 13). * R. H. Heilman: Heat insulation in air conditioning {In dustrial and Engineering Chemistry, Vol. 28, 1936, p. 782). I L. M. K. Boelter, J. T. Gier, and F. A. Ryder: Photoelec tric photometer for rapid comparison of two light sources {Illuminating Engineering Society Transactions, 1939). * Perry Moon: Scientific Basis of Illuminating Engineering (McGraw-Hill Book Co., New York, 1936). * Max Jakob: Heat Transfer (John Wiley A Sons, New York, Vol. 1, 1949). II L. E. Grinter: Numerical Methods in Engineering (The Macmillan Co., New York, 1949). u G. M. Dusinberre: Numerical Analysis of Heat Flore (Mc Graw-Hill Book Co., New York, 1949). . s " Max Jakob: Elements of Heat Transfer and Insulation (John Wiley A Sons, New York, 1942). '' 14 H. A. Johnson: Periodic heat transfer at the inner surface of a homogeneous wall (ASHVE Transactions, Vol. 54,1948. p. 143). - 11M. P. Heisler: Temperature charts for induction and con stant temperature heating {ASMS Transactions, Vol. 69, 1947, p. 227). .; : 14 F. C. W. Olsen: Temperatures in solids during heating and cooling (Industrial and Engineering Chemistry, Vol. 34. 1942. P-874). ^ :' ,T T. K. Sherwood and C. E. Reed: Applied'Mathematics in Chemical Engineering (McGraw-Hill Book Co., New York. 1939). * H. S. Carslaw: Introduction to the Mathematical Theory of the Conduction of Heat in Solids (Dover Publications, New York, 1945). w L. R. Ingersol), A. C.. Ingersoll, and O. J. Zobel: Heat Conduction (McGraw-Hill Book Co., New York, 1948, p. 209). * H. P. Gurney and J. Lurie: Charts for estimating tempera ture distribution in heating or cooling solid shapes {Industrial andEngineering Chemistry, Vol. 15,1923, p.,1170). " T. K. Sherwood: Applied Mathematics in Chemical En gineering (McGraw-Hill Book Co., New Yorkjp. 241). "A. Nessi and L. Nissolle: Mithodes Graphigues pour L'tiude des Installations de Chauffage et de Riffiguration en Rigimc Discontinu (Dunod, Paris, 1949). ** R. L. Perry and W. P. Berggren: Transient Heat Conduc tion in Hollow Cylinders after Sudden Change of Inner Surfaoe Temperature (University of California, Publications in Engi neering 5, Vol. 59, 1944). u v. Paschkis: Method for determining unsteady-state heat transfer by means of electrical analogy (ASMS Transactions. Vol. 64, 1942, p. 105). CHAPTER & PHYSIOLOGICAL PRINCIPLES Chemical V/fiction of Air, Physical Impurities in Air, Thermal Interchanges Between the Body and Its Environment, High Temperature Hazards, Acclimatization, Upper Limits of Heat for Men at Work, Application of Physiologic Principles to Air-Conditioning Problems, Effective Temperature Index and Comfort Zones . ENTILATION is defined in part as the process of sup remove objectionable body odors, or tobacco smoke. The con Vplying air to, or removing air from, any space by natural centration of body, odor in a room, in turn, depends upon a or mechanical means. The word in itself implies,quantity, butnumber of factors, including the dietary and hygienic habits air must be of the proper quality also. The term air con of the occupants (frequently reflecting their socio-economic ditioning in its broadest sense implies control of any or all status), the outdoor air supply, air space allowed per person, of the physical or chemical qualities of the air. The ASHVE odor adsorbing capacity of air-conditioning processes, and Code of Minimum Requirements for Comfort Air Condition temperature and relative humidity. The intensity of odor ing1 defines it "as the process by which simultaneously the sensation has been found to vary as the logarithm of the con temperature, moisture content, movement and quality of the centration of the odoriferous substance in tbe air, or inversely air in enclosed spaces intended for human occupancy may be with the logarithmic function of the amount of outdoor air maintained within required limits. If an installation cannot supplied and the air space per person. perform all of these functions, it shall be designated by a The relation between air supply and occupancy has been name that describes only the function or functions per reported by the Harvard School of Public Health* (Table 1) formed." See definition of air conditioning in Chapter 1. and the ASHAE Research Laboratory * Outdoor air require- CHEMICAL VITIATION OF AIR Table 1 .... Minimum Outdoor Air Requirements to Remove People living indoors bring about certain physical and Objectionable Body Odors Under Laboratory Conditions2 chemical changes in the air about them. The oxygen content of the air diminishes and the carbon dioxide increases, but these changes are too slight to be significant except in air tight spaces as in submarines. Organic matter which is usually perceived as odors, comes from the body or clothes. Moisture and heat are given of! by the body. There is no evidence of any toxic volatile material given off by man to the ambient air. Stale air may be offensive because of odors and may induce loss of appetite and loss of energy. Ob jectionable body odors have the same effects. These reasons, whether esthetic or physiological, usually make it desirable in Type of Occupenfs per Pertoo Cu Ft Outdoor Air SuppJy CFM per Perron Heating *ea*on with or without recirculation. Air not conditioned. Sedentary adults of average socio-j economic status............................... 100 200 300 500 25 16 12 7 the design of air-conditioning systems to provide for the elimination or control of odors arising from occupancy, cook ing,- or other sources. This may be accomplished by intro^ during odor-free air in sufficient quantities to reduce odor concentrations by dilution to a level which is not objection able. Odor-free air may be outdoor air or air which has been cleared of odors by sorption, washing, or other appropriate Laborers......................... ................................. Grade school children of average socio-j economic status.......................................{ 200 100 200 300 500 23 29 21 17 11 means. In the case of vitiation by a few hazardous gases such as carbon monoxide from heating, cooking, and certain in dustrial processes, no satisfactory chemical treatment for the elimination of the impurity has been found. The only satis factory solution is elimination at the source by local exhaust ventilation; or, if this is impossible, reduction to a safe ' concentration by dilution. (See Chapter 7.) In tbe case of contamination by other matter, including volatile vapors and gases, chemical treatment for the removal or reduction of the Grade school children of lower socio economic status......................................... 200 , 38 Children attending private grade schools.......................................................... 100 22 Heating season. Air humidified by means of centrifugal humidifier. Wafer atomisation rate 6 to 10 gph. Total air circulation 30 cfm per person. Sedentary adults 200 12 impurities has been made available through air cleaning methods, which are dcii<gd in Chapter 24. When the only source of contamination is the human oc Sommer season. Afr cooled and dehumidified by means of a spray dehumtdffler. Sproy water changed daily. Total air circulation 30 cfm per person. cupant, and overheating is not a problem, the minimum quantity of outdoor air needed appears to be that required to Sedentary adults 200 <4- 61 62 CHAPTER 6 1959 Guide merits for removal of objectionable tobacco smoke odors are not accurately known, but available information and current practice indicate the need of 15 cfm per person or more.4 The total quantity of outdoor air to be circulated through an enclosure is often governed chiefly by the physical con siderations for controlling temperature, air distribution, and air velocity. Other factors which must be taken into con sideration, include the type and usage of the building, lo cality, climate, height of rooms, floor area, window area, extent of occupancy, and the operation of the system dis tributing the air supply. Frequently, some of these factors, particularly the need for air movement and good distribution, may be satisfied by recirculation of inside air rather than outside air. It will be noted that, with adequate air space, the rate of air change indicated in Table 1 is from 4 to 30 cfm per per son. In rooms occupied by only a few persons, such an air change will be automatically attained in cold weather by nor mal leakage around doors and windows, and can easily be secured in warm weather by the opening of windows. With a space allotment of 400 cu ft per person, only 1*4 air changes per hour are necessary to provide a ventilation rate of 10 cfm per person.' ' Therefore, in the ordinary dwelling with adequate cubic space allotment, no special provision for controlling chemical purity of the air is necessary (aside from removal of fumes from heating appliances). For such conditions, the control of air temperature is the major consideration. In more crowded rooms (large offices, large workrooms, auditoriums), where the cubic space per person is less and it is usually impossible to admit untempered outside air with out creating drafts, mechanical ventilation is essential. The present data regarding the effect of cubic space on outdoor air requirements are not universally accepted. The Code of Minimum Requirements for Comfort Air Condition ing1 prescribes definite minimum requirements which should be familiar to the designing engineer. It should be emphasized, however, that the code fixes minimum, rather than adequate requirements. (See also Tables 1 and 3 of Chapter 13.) Notwithstanding the rapid advance made in air condition ing, some persons still believe there is a stimulating quality in outdoor air (particularly country, mountain, and seashore air) under ideal weather conditions, which is lacking in arti ficially conditioned air. It is apparent, however, that modern air conditioning insures control of the phenomena of nature for the service and comfort of man independently of weather conditions. Freedom of movement, action, and thought, to gether with the variability of stimuli experienced by persons under ideal conditions in the country, mountains, or seashore, undoubtedly has some stimulating effect. Various experi menters have attempted to duplicate the invigorating quali ties of outdoor air by the use of ozone, ionization, or ultra violet light, but results to date have been inconclusive or negative.1 Ozone in amounts of 0D1 to 0.05 ppm of air is allowable in comfort air conditioning. Above this limit there is a pun gent, unpleasant odor and perhaps respiratory distress, de pression, and stupor* ' PHYSICAL IMPURITIES IN AIR Dust particles of almost any type can produce irritation of the mucous membranes of the nose and throat, if present in high concentrations. Certain dusts may be very harmful, but coal dust is tolerated well. The effects of various indus trial dusts, pollens, etc., are discussed in Chapter 7. A certain part of the dissemination of disease in confined spaces may be due to pathogenic organisms floating in the air like dust particles. (See Chapter 8.) While in some instances it may be possible to reduce the physical impurities of the air by dilution from a noncontaminated source, such a source is rarely available. Fre quently, outdoor air contains a higher concentration of phys ical impurities than indoor air. Therefore, it is usually desirable to reduce the concentration of physical impurities by air cleaning methods. (See Chapter 24.) THERMAL INTERCHANGES WITH BMVIRONMBMT Body temperature depends upon the balance between heat production and beat loss. Heat resulting from oxidation in the body (metabolism) maintains the body temperature well above that of the surrounding air in a cool or cold environ ment. At the same time, heat is constantly lost from the body by radiation, convection, and evaporation. Since, under or dinary conditions, the body temperature is maintained at its * Normal control, naked, <n cotorimeter at temperatures from 72A to 942 F. first column m each experiment represents heat production at d**terminod by indirect calorimetry, the second column, heat elimination. T7n portion marked with rertital Hoes represents voporiration/ the doited oree coovocfion. ftw tuunericed area, radiation, the dcin temperature repretentr Die aworaye reading of 18 ipofi on the surface. Fig. 1 .... Heat Loss from Human Being by Evaporation, Radiation, and Convection* normal level of about 98.6 F, the heat production must be balanced by the heat loss. During work, the body tempera ture may rise; in fact, afternoon temperatures of normal persons average 1 deg above the resting value of the morning whether working or not. The fundamental thermodynamic processes concerned in heat interchanges between the body and its environment may be described by the equation: where M - S + B R C (1) M rate of metabolism, heat produced within the body. S rate of storage, change in intrinsic body heat. E - rate of evaporative heat loss. R rate of radiative heat loss or gain. C ** rate of convective beat loss or gain. The rate of metabolism, M, is always positive. The storage, S, may be either positive or negative, depending upon whether Physiological Principles 63 heat is being stored or depleted owing to a rise or fall in body temperature. Under ordinary circumstances (when the dew point of the air is below the body surface temperature) the evaporation loss, E, is always positive; that is, heat from metabolism supplies this loss. R and C are positive when body surface temperature is above that of walls and air, and nega tive when it is below. DuBois/ after careful calorimeter studies on a fasting, nude man, plotted the partition of body heat loss and heat pro duction as a function of temperature. Fig. I shows some dis parity between heat production and heat loss. This disparity is S in Equation 1. In the central range of the experiments S was quite low and no increase in heat loss by vaporization was apparent. Within the range of 81-86 F air temperature, with still air, there is, for a resting nude man, a point at which his body Rg. 2 .... Relation Between Metabolism, Storage, Evaporation, Radiation Plus Convection, and Temperature for the Clothed Subiect has to tiiVe no particular action to maintain its heat balance. If he is clothed, or if he is active, this point will naturally lie at a lower level. At this point, which may be termed the neutral point for that individual, conditions are neither too hot nor too cold. If, through a fall in air temperature, or a rise in air movement, the rate of heat loss from the skin to the environment is increased, then the body must do some thing to counteract this heat loss. Over a certain range, the body can achieve this by decreasing the flow of blood through the skin. This will result in some cooling of the skin and sub jacent tissues, but the temperature of the deep tissues will be preserved. The range of external conditions over which this may be. achieved may be termed the zone of vaso-motor regulation against cold. Beyond this range, the temperature of the superficial tissues will fall still further, and that of the deep tissues will fall as well, unless some other steps are taken. The body normally does react; it increases heat pro duction by increasing muscular tension, by shivering, or by spontaneous increase in activity.* As long as these are ade quate to meet the increased rate of heat loss to the environ ment, a fall in deep body temperature may be prevented. Such conditions may be said to lie in the zone of metabolic regulation against cold. Beyond this point, the body enters the zone of inevitable body codling. Once body temperature starts to fall, man is headed for disaster. It will be seen that, in man, deep body temperature is pre served over an important range of cold external conditions, at the expense of (1) a fall in the temperature of the periph eral tissues, and (2) an increased expenditure of energy. As regards the first of these, the farther away superficial tissue lies from the central body mass, the more readily will its temperature fall. On the hot tide of the neutral point, there exists a zone of vaso-motor regulation against heat, corresponding to that against cold. The blood flow through the skin is increased when the opportunities for heat loss to the environment are restricted.* This increase in blood flow may double the con ductance of the superficial tissues over that characteristic of the neutral point, and the temperature of the skin surface may rise until it is only three degrees below that of the deep tissues. If this increase in blood flow is unable to balance the restriction in heat loss, the body has entered the next zone. Once again, the normal body takes steps to prevent a change in its deep temperature; but they are not the counterpart of the steps taken under similar circumstances on the cold side. There is, in fact, very little change in heat production, beyond that resulting from a disinclination for exertion. The second line of defense, on the hot tide, is a new and power ful method of promoting heat loss--the provision of water, by the operation of the sweat glands, for evaporative eooling. As long as evaporation is adequate to restore the detired heat loss, the body is in the zone of evaporative regulation against heat. When this ceases to be adequate, the body is in the zone of inevitable body heating. The body enjoys a little more latitude in this zone than it did in the corresponding zone on the cold tide, but when the deep temperature rises more than 4 deg F, it loses its efficiency. All factors which affect the evaporation of water from the skin affect heat regulation in the zone of evaporative regulation. Atmospheric vapor pres sure and air motion are meet important. With dry-bulb tem perature above body temperature, air motion facilitates evaporative heat loss by removing hot humid air from con tact with the skin and replacing it with relatively drier air. Heat regulation in man requires an intact set of sensory nerves, a normal sympathetic nerve supply to sweat glands and blood vessels, a great many sweat glands, and a circula tory system capable of carrying heat from muscles and viscera to the skin by circulation of the blood. Some of the phenomena of body temperature control are shown graphically in Fig. 2. The dotted curves, from a study at the John B. Pierce Laboratory of Hygiene," are for sub jects lightly clothed in a semi-reclining position, and give the relation between the dry-bulb temperature of the environ ment (with about 45 percent relative humidity) and the metabolic rate (heat production), the rate of heat dissipation by radiatioD and convection combined, and the latent heat loss due to evaporation from the skin and the respiratory tract. The smooth line curves from the work of the ASHAE Research Laboratory11 give the same relationships for healthy, male subjects (18 to 24 years of age), seated at rest and dressed in customary winter indoor clothing. The Pierce Laboratory data for the semi-reclining subjects also include the rate of heat storage (either positive or negative) due to a rise or fall in body temperature. For the normally clothed, subjects, a curve gives the total heat loss (that is, the sum of the radiation, convection, and evaporative losses). Here, 64 CHAPTER 6 1959 Guide Table 2 .... Physiological Responses to Heat of Men at Rest and at Wort* Effective Temp Acftiaf Cheek Temp (Fahr D*g) Roe m Rectal Temp (Fohr Deg per Hr) Men at Rest Increase in Pdse Rate (Beats per Min per Hr) Men at Wort 90,000 ft-.'fc of V.'oti par near Approximate Lot* in Body Weight by Perspiration (lb per Hr) Total Work Accomplished (ft-lb) Rise in Body Temp (Fahr Deg ' per Hr) Increase in Pube Rate (Beats per Min per Hr) Approximate Loss in Body W by Per spiration (Lb per Hr) GO 70 0.0 0 80 96.1 0.0 0 85 96.6 0-1 1 90 97.0 0-3 4 95 97.6 0.9 15 100 99.6 2.2 40 105 104.7 4.0 83 no 5.9b 137* * Dste by AfiHAB Beeesrch Laboratory. * Computed value from exposures lasting less thsa one bour. 0.2 0.3 0-4 0.5 0.9 1.7 2.7 4.0* 225,000 225,000 209,000 190,000 153,000 102,000 67,000 49,000 37,000 0.0 0.1 0.3 0.6 1.2 2.3 4.0* 6.0* 8.5* 6 7 11 17 31 61 103* 158* 237* 0.5 0.6 0.8 1.1 1.5 2.0 2.7* 3.5* 4.4* storage is given by toe difference between the metabolism and total beat loss. The small difference between the metabolic rates for the two groups of subjects may be accounted for by difference in activity. Heat exchange between the body and the environ ment by radiation and convection is greater for the lightly clothed subject, both for cool conditions where there is ex cessive heat loss, and for very warm conditions where there is transfer of heat from the atmosphere to the body. The two curves for evaporative loss serve to show how physiological control uses evaporation of sweat to maintain equilibrium at high temperatures. Below 75 F, for the normally clothed sub ject, and below 85 F for toe lightly clothed subject, evapora tion loss is minimal and constant. Burch" has shown that this insensible perspiration reflects the permeability of the skin to the moisture of the body. Above these temperatures, con trol is obtained by the availability of sweat for evaporation. The difference in the curves above 75 F is probably largely determined by the difference in clothing and activity. In the rone of evaporative heat regulation, air movement facilitates heat loss if the temperature of the air js not above that of the skin." Under hot, dry conditions air movement may be of little advantage, or even of disadvantage, if it in creases the addition of heat to the skin by conduction more than it promotes the loss of heat from the skin by evapora tion. HIGH TEMPERATURE HAZARDS Studies at the ASHAE Research Laboratory" and else where during the past two decades have made available much information dealing with the physiological effects of hot atmospheres on workers, and means of alleviating the distress and hazards associated therewith. Table 2 gives some of the physiological responses of men, at rest and at work, to hot environments. Frequent and continued exposure of workers to hot environments results in physiological derange ment affecting the leucocyte count of the blood, and other factors dealing with man's mechanism of defense against in fection. Wherever 5 (Equation 1) becomes strongly positive and body tempprature rises progressively, men will continue to work until body temperature reaches 103 F. When these body temperatures are exceeded, men work with declining efficiency and may be subject to heat stroke. Heat exhaustion is a circulatory failure is which the venous return to the heart is reduced so that fainting results." Early symptoms of heat exhaustion may include fatigue, headache, dizziness when erect, loss of appetite, nausea, abdominal dis tress, vomiting, shortness of breath, flushing of face and neck, pulse rate above 150, glazed eyes, and mental disturb ances such as apathy, poor judgment, and irritability which usually precede fainting (syncope). Recovery is usually prompt when the man is removed to a cool place and kept lying down for a time, unless he has some other illness such as heart disease. Heat cramps are painful muscle spasms in extremities, back, and abdomen due, at least in part, to excessive loss of salt in sweating. Formerly common in hot industries, this manifestation of illness due to heat is now greatly reduced by drinking water containing 0.1 percent salt, or by proper use of salt tablets. Heat cramps are readily alleviated by ad ministration of salt solution intravenously. Heat stroke is a serious effect of exposure to great heat. The body temperature climbs rapidly to excessive levels often above 105 F when for unknown reasons free sweating suddenly stops. At such high temperatures, coma appears and death may be imminent. Emergency measures are re quired to reduce the excessive body temperature by cooling quickly to avoid irreparable damage to the brain." The deleterious physiologic effects of high temperatures exert a powerful influence upon physical activity, accidents, sickness, and mortality. Both laboratory and field data show - that physical work in warm atmospheres is a great effort, and that production falls progressively as the temperature rises. . ACCLIMATIZATION When men move to deserts or to jungles some adaptation to the climate takes place. If work is gradually increased day by day, and if the men can get plenty of water and salt, and can sleep each night, acclimatization may be complete in 7 to 10 days. The acclimatized man works with a lower heart rate, lower skin and rectal temperature, and more stable blood pressure than when unacclimatized. The process of ac- Physiological Principles Table 3 .... Upper Limits of Environmental Conditions for Acclimatized, Healthy, Young Men in Military Service Reocfiofts at the end of 4 hr - Rectal Temp F Relatively easy----- Below 101 101 to 102 Above 102 Pulse Rate Below 130 130 to 145 . Over 145 climatization requires work in the heat." During the recent war, white troops lived and did hard physical work for long periods in tropical conditions when disease hazards were con trolled. In recent tests made at the ASHAE Research Laboratory," subjects were required to perform light work under very hot conditions for a 4-hr period each day. It was found that the ability of a new subject to endure these conditions showed daily improvement for a period of at least 2 weeks. However, after acclimatization was completed, a recess of several days had no effect on the endurance of the subject. Individuals differ widely in their capacity to acclimatize. Acclimatized men lose most of these improvements in a few weeks of tem perate climate, even though they are vigorously active. In the course of acclimatization, the sweat glands come to se crete fluid less rich in salt." For all except those carrying out really hard woik in hot, dry atmospheres, this effects an im portant saving in salt loss, and makes all the difference be tween being exposed and not being exposed to the risk of heat cramps. The adaptive level changes somewhat with the season. There are also marked differences between the sexes. In the cold zone the thickness of thermal insulating tissues of women is almost double that of men, although the sensory responses to cold are similar. In the hot zone, the threshold of sweating is higher for women. The thickness and insulating value of toe clothing worn are also important factors in the determination of the comfort level. UPPER LIMITS OF HEAT FOR MEN AT WORK In very hot conditions humidity is the limiting factor, and the wet-bulb temperature assumes great importance. In 1905 Haldane recognized tost 88 F wet-bulb was the limit of en durance for coal miners, and later observers have concurred. A study was made at the Armored Medical Research OftY KAB TEKPCRATmz, F fig. 3 .... Heat Endurance of Acclimatized Subjects Working at a Specific Rate* 65 Laboratory" to determine- the upper limits of environmental conditions under which a man can perform certain work. Thirteen enlisted men, thoroughly acclimatized to the hot conditions, served as subjects. During each test, the subjects were required to march for 4 hr at the rate of 3 mpb, carrying 20 lb packs under a wide range of environmental conditions which were rated as relatively easy, difficult, and impossible, on the basis of the physiological reactions of the subjects at the end of the 4-hr period as shown in Table 3 and Fig. 3. Recognition of the need of air conditioning for workers in hot industries is growing rapidly. The choice of the type of system to be used in any given instance, must be determined by the air-conditioning engineer after a study of conditions (see Chapter 51, Control of Industrial Environment). In some hot industries where few people are working in large spaces the worker himself, rather than the atmosphere, can fig. 4 .... Effect of MRT Elevation in Terms of Effective Temperature be cooled by placing him in a small booth, and blowing cooled air over him, or by circulating cooled air through a loose fitting suit" The ASHAE Laboratory has studied the effects of walls of higher temperature than the air." The findings are in part shown in Fig.,4. It will be seen that the importance of mean radiant temperature, as compared with that of the effective temperature,' decreases as the effective temperature rises', and also, to a certain extent, as the mean radiant temperature itself rises. The lower of the two curves relates to conditions in which the.MRT was kept approximately at the level of the DBT. If this curve is followed, it will be seen that, at 80 ET, a little more than 1 deg rise in MRT produces the same effect as 1 deg rise in ET; but when the ET is 92 deg, it takes a rise of 11 F deg in the MRT to produce the same effect as 1 deg rise in ET. The upper curve relates to con ditions in which the MRT was kept about 40 F deg higher that the DBT. It will be seen that under these conditions, a rise in MRT is less effective, even at low values of ET; and that it loses its relative effectiveness more rapidly as toe ET rises. It should not be assumed, however, that MRT does not matter much. All that these comparisons indicate is that unit rise in MRT becomes less important as compared with unit rise in ET, as conditions get hotter. This may be due more to a growing importance of unit rise in ET than to a Himinitoing 1 66 CHAPTER 6 1959 Guide promise. The zone of thermal neutrality differs with clothing, season, activity, and all the other factors controlling heat production (Table 4). The comfort zone is very similar to the zone of thermal neutrality. Sensations of warmth or cold depend not only on the tem perature of the surrounding air as registered by a dry-bulb thermometer, but also upon the temperature indicated by a wet-bulb thermometer, upon air movement, and upon radia tion effects. Dry air at a relatively high temperature may feel cooler than air of lower temperature with a high moisture content. Air motion makes any moderate condition feel cooler. Radiation to cold or from warm surfaces is another important factor under certain conditions affecting the com fort reaction of the individual. Fig. 5 .... Relotion Between Total Heat Loss from the Human Body and Effective Temperature for Still Air*-14 importance of unit rise in MRT. Under ordinary still air con ditions the effepts of air temperature and MRT appear to be interdependent. Various authorities give 03 to 1 deg increase of room temperature to compensate for 1 deg depression of the MRT. APPLICATION OF PHYSIOLOGIC PRINCIPLES TO AIR-CONDITIONING PROBLEMS In order to estimate cooling loads in occupied spaces it is necessary to know the metabolic rate (heat production) of man. This has been studied extensively, and found to remain relatively constant per unit of body surface area in a subject fasting and resting quietly after a good night's sleep. The rate is high in children, and diminishes gradually with age; it in creases in certain diseases and in the presence of fever. The metabolic rate is somewhat lower in women. Heat production goes up sharply with work and varies widely in different per sons doing the same work. Figs. 5, 6, and 7 and Table 27 of Chapter 13 give sufficient basic data for estimating heat pro duction and heat loss under various conditions. EFFECTIVE TEMPERATURE INDEX AND COMFORT ZONES There is no precise physiologic observation by which com fort can be evaluated. Mean skin temperature offers some * Sm footnote a, Fig. 5. Fig. 6 ..., Relation Between Radiation and Convection Loss from the Human Body and Dry-Bulb Temperature for Still Air*-14 Combinations of temperature, humidity, and air move ment which induce the same feeling of warmth are called thermo-equivalent conditions. A series of studies" at the ASHAE Research Laboratory established the equivalent con ditions for practical use. This scale of thermo-equivalent con ditions not only indicates the sensation of warmth, but also to a considerable degree determines the physiological effects on the body induced by heat or cold. For this reason, it is called the effective temperature scale or index, and it denotes sensory heat level. Effective temperature is an empirically determined index of the degree of warmth perceived on exposure to different combinations of temperature, humidity, and air movement. It was determined by trained subjects who compared the relative warmth of various air conditions in two adjoining conditioned rooms by passing back and forth from one room to the other. The numerical value of the index for any given air con ditions is fixed by the temperature of slowly moving (15 to Physiological Principles 25 fpm air movement) saturated air which induces a like sensation of warmth or cold. Thus, any air condition has an effective temperature of 60 deg when it induces a sensation of warmth like that experienced in slowly moving air at 60 F saturated with moisture. The effective temperature index. cannot be measured directly, but is determined from dryand wet-bulb temperatures and air motion observations by reference to an Effective Temperature Chart (see Figs. 8, 9, and 10) or tables. Fig. 8 gives the effective temperature for any combination of dry- and wet-bulb temperatures for still air (15 to 25 fpm) conditions. Charts similar to Fig. 8 for air velocities of 100 and 300 fpm have been presented in earlier editions of The Guide, eg., 1939. Fig. 9 is another form of effective 67 Table 4 .... Comparison of Comfort Ranges With Zone of Thermal Neutrality tnvortigator* effective Temperature Optilin* Ronge Temp Remart* Hpughten and 66 Yaglou Comfort Zone 63-71 Yaglou and 71 Drinker 66-75 Yaglou 72.5 66-82 Keeton et al 75 74-76 Winter nonbasal; at rest, normally clothed. Men and women. Summer nonbasal; at rest and nor mally clothed. Men Entire year; non basal; at rest and stripped to waist. Men. Entire year; basal, nude. Steady state (9 hr exposure). Men and women. Zona of thermal Neutrality DuBols and 75 73.2-76.9 Basal; nude; men. Hardy 71.8 64.8-76-0 Basal; clothed; men. Winslow, Her- 84.0-87.8 Nonbasal; at rest; rington, and nude; men. Gagge 74 -84 Nonbasal; at rest; clothed; men. . * See footnote a. Fig. 5. Fig. 7.... Evaporative Heat and Moisture Loss from the Human Body in Relation to Dry-Bulb Temperature for Still Air Conditions*'14 temperature chart embodying all three variables: dry-bulb and wet-bulb temperatures, and air velocity. As stated previously, effective temperature is an index of the degree of warmth experienced by the body. An effective temperature line is, therefore, a line defining the various com binations of conditions which will induce like' sensations of warmth. It does not necessarily follow that like sensations of comfort will also be experienced along the entire length of an effective temperature line. Some degree of discomfort is likely to be experienced at very high or very low relative humidities, regardless of the effective temperature. It has also been found that the optimum effective temperature varies with the season, and is lower in winter than in summer. Tests1* made at the ASHAE Research Laboratory in very hot conditions, with subjects doing light work, were in very close agreement with the effective temperature chart. Other work" under similar environmental conditions, but with sub jects walking 3 mph and carrying 20 lb packs, indicated that the effective temperature lines should be more nearly hori zontal. It therefore appears that the slope of the ET lines may vary, depending upon the rate of work being performed. Fig. 10 shows the ASHAE Comfort Chart" as published since 1950. The areas and arrows indicating the summer and winter comfort zones on the previous charts have been re moved. The summer comfort zone was removed because it extended to temperatures where too large a percentage of the people would be uncomfortable. The winter comfort zone was removed for the same reason, and because of inadequate data in later studies. The distribution curve, showing the percent of people feeling comfortable at various effective temperatures in eum- mer, indicates that a maximum of 98 percent of the people were comfortable.at 71 ET. The study was conducted with relative humidities between 30 and 70 percent. The distribution curve shown on the previously used chart, showing the percent of people feeling comfortable at various effective temperatures in the winter, was based on research prior to 1932. This curve indicated that at 66 ET a maximum number of people were comfortable. Later studies" by the ASHAE Research Laboratory indicated that a maximum of 97.7 percent of the people were comfortable at 68 ET, and this finding has been confirmed by current practice." How ever, adequate data from the later studies were available only for the ET range of 65 to 69, as presented in Fig. 10. The studies should be extended to cover a wider range. The lighter weight clothing, probably worn in the later studies, accounts for the higher desirable ET. 68 CHAPTER 6 1959 Guide physiological Principles 69 variations in lynsarinn of comfort among individuals may be greater for any given location than variations due to ft differ ence in geographical location. The available information indi cates that changes in weather conditions over a period of a few days do hot alter the optimum indoor temperature. Laboratory studies of Keeton and others,8 and years of practical- field experience show that the adjustments in the heat'regulatory mechanisms of healthy people on entering and leaving air-conditioned spaces are prompt, easy, and safe. Sudden sensation of coolness on entering a cooled room from the hot street.is asociated with sweat on the skin and in the clothing.' Several minutes are required for the dan tempera ture to'fall'and the free moisture to disappear.'Even am bulatory heart patients endure such changes with ease. The use of the word shock to describe any part of these adjust ments is unwarranted. . Upon leaving an air-cooled space and re-entering a hot atmosphere,- sudden wanning occurs. Experiments at the ASHAE Research Laboratory8 and elsewhere" indicated no demonstrable harm to a healthy individual. Adaptation oc curred as soon as normal perspiration was established. Mild exercise'shortened the adaptation time. Most healthy, sedentary, and slightly active men and women, normally clothed and in uniform environments, with air velocities of the order of 25 fpm, are thermally com fortable the year around when the dry-bulb air temperature is in the range 73 to 77 F and the relative humidity is in the range of 25 to 60 percent.8 Satisfactory comfort conditions for persons at work8 vary, depending upon the rate of work and the amount of clothing worn. In general, the greater the degree of activity, the lower the effective temperature necessary for comfort. Clothing has been evaluated for its overall insulation effects by a physical unit, the do which equals 0.116 C deg per (kilogram calorie) (square meter) (hour).8 Yaglou" criticizes the concept of overall insulation, and points out that different parts of the body require different amounts of insulation. The literature on effects of clothing is difficult to coordinate at the present time, as much of it is still in military service reports which are yet to be published and amplified. For prematurely bom infants, the optimum temperature varies from 100 to 75 F, depending upon the stage of develop ment. The optimum relative humidity for these infants is placed at 65 percent.8 No data are yet available on the op- Radiation from occupants to room surfaces, and between the occupants, has an important bearing on the feeling of warmth, and may alter to some measurable degree the op timum conditions for comfort previously indicated. Since the mean radiant temperature of a space is affected by cold walls and windows, as well as by the warm surfaces of heating units-placed within the room or embedded in the walls, these factors must be compensated. Likewise, in densely occupied spaces, such as .classrooms, theaters, and auditoriums, tem peratures somewhat lower than those indicated by the com fort line may be desirable because of counter-radiation be tween the bodies of occupants in close proximity to each other. Such radiation will also elevate the maan radiant temperature of the room. Many field studies8 have been made to determine the optimum indoor effective temperature for both winter and summer in several metropolitan districts of the United States and Canada, in cooperation with the managements of offices employing large numbers of workers (Fig. 11). On the whole, women of all age groups studied prefer an effective tempera ture for comfort 1.0 deg higher than men. Ail men and women over 40 years of age prefer a temperature 1 deg ET higher than that desired by persons below this age. The per sons serving in all of these studies were representative of office workers dressed for air-conditioned spaces in the sum mer season, and engaged in the customary office activity. On the h*sis of present knowledge, for different geographi cal regions and age groups, the most popular temperature varies from a low of 66 ET in winter to a high of 73 ET in summer. The spread for summer comfort is 69 to 73 ET. A spread of 3 deg in the optimum effective temperature for summer cooling is ascribed to geographical location. However, A. Clothing: Customary Indoor dotJung. B. Activity: Sedentary or light muscular work. C Hooting Method*.- Convection type, Le., worm >, d/rect tfeom or hot wafer radiators, plenum lytfesu. -- - - 1 Fig. 9 .... Effective Temperature Chart Showing Normal Scale of Effective Temperature, Applicable to . Inhabitants of the United States Under Following Conditions: n 70 CHAPTER 6 1959 Guide DRY BULB TEMPERATURE F * Note--Both BNMwr and winter comfort Knot apply to mAobitanfe of the United State* only. Appficottan of winter comfort fine is further limited to room booted by control systems of the conrechoo typo. The fine doe* not apply to room* booted by rodtenf methods. Application of cvamer'comfort line is limited to homes, offices, and Che file, whore (ho occupants become fully adopted to the artificial ait conditions. The fine doe* not apply to theater*, department stores, and the Pee where (he exposure is less than 3 hour*. The summer comfort line shown pertain to Pittsburgh and to other cities in the northern portion of (he United States and Southern Canada, and at elevation* no! so excess of 1000 f! above sea level. An increase of one dep FT should be mode approximately per S deg reduction in north latitude. * Dotted portion of winter comfort fine was extrapolated beyond test data. Fig. 10 .... ASHAE Comfort Chart for Stilt Air*>b Physiological Principles . timum air conditions for full term infants and young children up to school age. Satisfactory air conditions for these age groups are assumed to vary from 75 to 68 F with natural indoor humidities. Fot children (having high metabolism) at school, in winter clothes, 70 F has been considered correct, with 55 F recommended for gymnasiums. REFERENCES 1 Code of minimum requirements for comfort air conditioning (ASHVE Transactions, Vol. 44, 1938, p. 27). *C. P. Yaglou, E. C. Riley, and D. J. Coggins: ASHVE Research Report No. 1031--Ventilation requirements (ASHVE Transactions, Vol. 42, 1936, p. 133). " *F. C. Houghten' and J. L. Blackshaw: ASHVE Research Report No. 959--Indices of air change and air distribution (ASHVE Transactions, Vol. 39,1933, p. 261). * C. S. Leopold: Tobacco smoke control--A preliminary study (ASHVE Transactions, Vol. 51, 1945, p. 255). *C. P. Yaglou, L. C. Benjamin, and S. P. Choate: ASHVE Research Report No. 921--Changes in ionic content in oc cupied rooms ventilated by natural and mechanical methods (ASHVE Transactions, Vol. 38, 1932 p. 191). C. P. Yaglou, A. D. Brandt, and L. C. Benjamins" ASHVE Research Report No. 965--Physiologic changes during exposure to ionised air (ASHVE Transactions, Vol. 39, 1933, p. 357). C. P. Yaglou and L. C. Benjamin: ASHVE Research Report No. 985--Diurnal and seasonal variations in the small ion content of outdoor and indoor air (ASHVE Transactions, Vol. 40, 1934, p. 271). L. B. Loeb: The nature of ions in air and their possible physiological effects (ASHVE Transactions, Vol. 41, 1935, p. 101). L. P. Herrington: The influence of ionised air upon normal subjects (Journal Clinical' Investigation, 14, Januaiy 1935). L. P. Herrington and K. L. Smith: The effect of high concentration of light negative atmospheric ions on the growth and activity of the albino rat {Journal Industrial Hygiene, 17, November 1935). C.-E. A. Winslow and L. P. Herrington: Subjective reactions of human beings to certain outdoor atmospheric conditions (ASHVE Transactions, Vol. 42, 1936, p. 119). * Editorial (The British Medical Journal, June 25, 1932, p. 1182). . * E. F. DuBois: The mechanism of heat loss and temperature regulation, (Lane Medical Lectures, Stanford University Pub lications, Medical Science, Vol. 3, No. 4, 1937, p. 348; also 71 Transactions of the Association of American Physicians, Vol. 51, 1936, p. 252) 'E. J. Adolph and G. W. Molnar: Exchanges of heat and tolerance to cold in men exposed to outdoor weather (American Journal of Physiology, Vol. 146, 1946, p. 507). F. K. Hick, R. W. Keeton, N. Glickman, and H. C. Wall: ASHVE Research Report No. 1108--Cardiac output, periph eral blood flow and blood volume changes in normal indi viduals subjected to varying environmental temperatures (ASHVE Transactions, Vol. 45, 1939, p. 123). * C.-E. A. Winslow, T. Bedford, E. F. DuBois, R. W. Keeton, A. Missenard, R. R. Sayers, and C. Tasker: ASHVE Research Report No. 1107--Recent advances in physiological knowledge and their bearing on ventilation practice (ASHVE Transac tions, Vol. 45, 1939, p. 111). u F. C. Houghten, W. W. Teague, W. E. Miller, and W. P. Yant: ASHVE Research Report No. 830--Heat and moisture losses from the human body and their relation to air condition ing problems (ASHVE Transactions, Vol. 35, 1929, p. 245). " G. E. Burch and T. Winsor: Rate of insensible perspiration (diffusion of water) locally through living and through dead human skin (Archives of Internal Medicine, Vol. 74, 1944, p. 437). " N. A. Nelson, W. B. Shelley, S. M. Horvath, L. W. Eicfana, and F. F. Hatch: The influence of clothing, work and air move ment on the thermal exchanges of acclimatized men in various hot environments (Journal of Clinical Investigations, Vol. 27, 1948, p.-209). "W. J. McConnell and F. C. Houghteo: ASHVE Research Report No. 654---Some physiological reactions to high temper atures and humidities (ASHVE Transactions, Vol. 29, 1923, p. 129). W. J. McConnell, F. C. Houghten, and F. M. Phillips: ASHVE Research Report No. 672--Further study of physio logical reactions (ASHVE Transactions, Vol. 29, 1923, p. 353). W. J. McConnell, F. C. Houghten, and C. P. Yaglou: ASHVE Research Report No. 690--Air motion, high temperatures and various humidities--reactions on human beings (ASHVE Transactions, Vol. 30,1924, p. 167). W. J. McConnell and C. P. Yaglou: ASHVE Research Report No. 718--Work tests con ducted in atmospheres of high temperatures and various hu midities in still and moving air (ASHVE Transactions, Vol. 31, 1925, p. 101). W. J. McConnell, C. P. Yaglou, and W. B. Fulton: ASHVE Research Report No. 719--Basal metabolism before and after exposure to high temperatures and various humidities (ASHVE Transactions, Vol. 31, 1925, p. 123). F. C. Houghten, W. W. Teague, W. E. Miller, and W. P. Yant: ASHVE Research Report No. 90S--Heat and moisture losses from men at work and application to air conditioning problems (ASHVE Trans actions, Vol. 37, 1931, p. 541). W. L. Fleisher, A. E. Stacey, Jr., F. C. Houghten, and M. B. Ferderber: ASHVE Research Re port No. 1106--Air conditioning in industry--Physiological reactions of individual workers to high effective temperatures (ASHVE Transactions, Vol. 45, 1939, p. 59). F. C. Houghten, A. A. Rosenberg, and M. B. Ferderber: ASHVE Research Report No. 1153--Seasonal variations in reactions to hot at mospheres (ASHVE Transactions, Vol. 46, 1940, p. 185). " R. W. Keeton, F. K. Hick, Nathaniel Glickman, and M. M. Montgomery: ASHVE Research Report No. 1151--The pe ripheral type of circulatory failure in experimental heat ex haustion (ASHVE Transactions, Vol. 46, 1940, p. 157). " M. W. Heilman and E. S. Montgomery: Heat disease: clinical and laboratory studies (Journal of Industrial Disease and Toxicology, 18: 651, 1936). 1TL. W. Eichna, W. B. Bean, W. F. Ashe, and N. Nelson: Performance in relation to environmental temperature (Bul letin of Johns Hopkins Hospital, Vol. 76, 1945, p. 25). "C. M. Humphreys, Oscar lmalis, and Carl Gutberlet: Physiological response of subjects exposed to high effective temperatures and elevated mean radiant temperatures (ASHVE Transactions, Vol. 52, 1946, p. 153). "D. B. Dill: Life, Heat and Altitude (Harvard University Press, Cambridge, 1938). * L. W. Eichna, W- F. Ashe, W. B. Bean, and W. B. Shelley: The upper limits of environmental heat and humidity tolerated 72 CHAPTER 6 1959 Guide by acclimatized men working in hot environments (The Journal Industrial Hygiene end Toxicology, Vol. 27, March IMS, p. "F. C. Houghten, M. Ferderber, and Carl Gutberlet: ASHVE Research Rejvkt No. ii<y>--Local cooiing of workers in hot industry (ASHVE Transactions, Vol. 47, 1941, p. 403). F. C. Houghten and C. P. Yaglou: ASHVE Research Re post No. 673--Determination of the comfort zone (ASHVE Transactions, VoL 29, 1923, p. 361). F. C. Houghten and C. P. Yaglou: ASHVE Research Repost No. 691--Cooling effect on human beings produced by various air velocities (ASHVE Transactions, Vol. 30, 1924, p. 193). C. P. Yaglou and W. E. Miller: ASHVE Reseabch Report No. 717--Effective tempera ture with clothing (ASHVE Transactions, Vol. 31,1925, p. 89). F. C. Houghten, W. W. Teague, and W. E. Miller: ASHVE Research Report No. 755--Effective temperature for persons lightly clothed and working in still air (ASHVE Transactions, Vol. 32, 1926, p. 315). C. P. Yaglou, W. H. Carrier, Dr. E. V. Hill, F. C. Houghten, and J. H. Walker: How to use the ef fective temperature index and comfort charts (ASHVE Trans actions, VoL 38, 1932, p. 410). "Thomas Chester, N. D. Adams, C. R. Bellamy, G. D. Fife, E. P. Heckel, Dr. W. j. McConnell, F. C-McIntosh, A. B. Newton, B. F. Raber, and C. Tasker: ASHVE Resrasch Report No. 1196--Comfort with summer air conditioning (ASHVE Transactions, Vol. 48,1942, p. 107). - "C. S. Leopold: Conditions for comfort (ASHVE Transac tions, Vol. 53, 1947, p. 295). . "A. B. Newton, F. C. Houghten, Carl Gutberlet, R. W. Qualiey, and M. C. W. Tomlinson: ASHVE Research Repost No. 1102--Shock experiences of 275 workers after entering' and leaving cooled and air conditioned offices (ASHVE Transac tions, Vol. 44, 1938, p. 571). N. Giickman, T. Inouye, S. E. Telser, R. W. Keeton, F. K. Hick, and M. K. Fahnestock: Phys iologic adjustments of human beings to sudden change in en vironment (ASHVE Transactions, Vol. 53, 1947, p. 327). N. Giickman, Tohru Inouye, R.'W. Keeton, MD, I. W. Callen, MD, F. K. Hick, M.D. and M. K. Fahnestock: ASHVE Re search Report No. 1350--Physiological adjustments of normal subjects and cardiac patients to sudden changes in environment (ASHVE Transactions, Vol. 55,1949, p. 27). F. K. Hick, MD Tohni Inouye, R. W. Keeton, MD, N. Giickman, and M. k! Fahnestock: ABHVE Research Report No. 1447--Physiological adjustments of clothed human beings to sudden changes in en vironments--first hot moist and later comfortable conditions (ASHVE Transactions, Vol. 58, 1952, p. 189). Tohru Inouye F; K. Hick, MD., R. W. Keeton, MI), J. Losch. and N.' Giickman: ASHVE Research Report No. 1463--A comparison of physiological adjustments of clothed women and men to sudden changes in environment (ASHVE Transactions, Vol. 59, 1953, p. 35). Tohru Inouye, F. K. Hick, MD, R. W. Keeton, MD., and Lionel Bernstein, MD.: ASHVE Research Report No. 1508--Physiological responses to sudden change in atmos pheric environment--Studies of normal subjects, obese, hyper thyroid and hypothyroid patients (ASHVE Transactions, Vol 60, 1954, p. 315). ** F. C. Houghten, F. E. Giesecke, C. Tasker, and Carl Gutberlet: ASHVE Research Report No. 1055--Cooling re quirements for .summer comfort air conditioning (ASHVE Transactions, Vol. 43,1937, p. 145). BA. P. Kratz, S. Konzo, M. K. Fahnestock, and E. L. Broderick: ASHVE Research Report No. 1012--Study of sum mer cooling in the research residence for the summer of 1934 (ASHVE Transactions, Vol. 41, 1935, p. 207). C. P. Yaglou: ASHVE Research Report No. 1319--A method of improving the effective temperature index (ASHVE Transactions, Vol. 53,1947, p. 307). Tohru Inouye, F. K. Hick, MD., S. E. Telser, MD., and R. W. Keeton, MD.: ASHVE Research Report No. 1480--Effect of relative humidity on heat loss of men exposed to environments of 80, 76, and 72 F (ASHVE Transactions, Vol. 59, 1953, p. 329). M. K. Fahnestock and J. E. Werden: En vironment, comfort, health and people {Refrigerating Engi neering, February 1956, p. 43). " F: C. Houghten, W. W. Teague, and W. E. Miller: ASHVE Research Report No. 755--Effective temperature for persons Lightly clothed and working in still air (ASHVE Transactions, Vol. 32, 1926, p.315). . "A. P. Gagge, A. C. Burton; and H. C. Gazett: A practical system of units for the description of the heat exchange of man with his environment (Science, Vol. 94, 1941, p. 428). _ *C. P. Yaglou: Thermal insulation of clothing (ASHVE Transactions, Vol. 54, 1948, p. 291). *C. P. Yaglou. Philip Drinker, and K. D. Blackfan: Appli cation of air conditioning to premature nurseries in hospitals (ASHVE Transactions, Vo\. 36,1930, p. 383). CHAPTER 7 AIR CONTAMINANTS Classification of Air Contaminants; Sizes of Airborne Particles; Air Pollution by Smoke, Ash, and Cinders; Smoke Abatement and Air Pollution Control; Odor Nuisance; Industrial Air Contaminants, Flammable Gazes and Vapors; Combustible Dusts; Atmospheric Pollen; Airborne Bacteria; Radioactive Air Contaminants HE normal constituents of the earth's atmosphere are Fumes are solid particles commonly formed by the conden Toxygen, nitrogen, carbon dioxide, water vapor, argon, sation of vapors from normally solid materials such as molten small or negligible amounts of other inert gases, hydrogen,,metals. Metallic fumes generally occur as the oxides in air variable traces of ozone, and small quantities of microscopic because of the highly reactive nature of finely divided matter. and submicroscopic solid matter, sometimes called permanent Fumes may also be formed by sublimation, distillation, cal atmospheric impurities. From the viewpoint of'the air-con cination, or chemical reaction, whenever such processes cre ditioning engineer, all other airborne substances may be ate airborne particles predominantly below the 1 micron size. termed contaminants. This term is applied preferably, how Fumes permitted to age tend to flocculate into clumps or ag ever, to undesirable or chance impurities, since the occasion gregates of larger aze, thereby facilitating removal from air. may arise for adding to the air controlled amounts of solid or Smokes are the extremely small solid particles produced gaseous diluents for the prevention of explosions; germicidal - by incomplete combustion of organic substances such as to vapors or mists (aerosols) for bacteria control; masking bacco, wood, coal, oil, tar, and other carbonaceous materials. substances for odor control; or a substitute-for one of the The term smoke is commonly applied to the mixture of solid, normal gases, as, for example, when helium is used to replace liquid, and' gaseous products of combustion, although the nitrogen in atmospheres for compressed air workers or divers. technical literature prefers to distinguish between such com Since control of the chemical quality of air'is one of the ponents as soot or carbon particles, fly-ash, cinders, tarry functions of complete air conditioning, some knowledge of the matter, unburned gases, and gaseous combustion products. composition, concentration, and properties of air contami The finest particulate constituents are much less than 1 mi nants undeT various circumstances is essential to the air con cron in size, often in the range of 0.1 to OB micron. ditioning-engineer. _- Air contaminants arise from the normal processes of wear, Mists and Fogs erosion, windstorm, sea-spray evaporation, thermal disinte gration, earthquake, volcanic eruption, combustion, manu facturing, transportation, agriculture, and the biochemical or biological processes of life. They are classified at various times as organic and inorganic, viable or invisible, microscopic or macroscopic, particulate or gaseous, toxic or harmless, bene ficial or .destructive. The following classification, is'based chiefly upon the origin- or method of formation of air con taminants. Mists are very small airborne droplets of materials that are ordinarily liquid at normal temperatures and pressures. They may be formed by atomizing, spraying, splashing, mixing, violent chemical reaction, electrolytic evolution of gas from a liquid, or escape of a dissolved gas upon release of pressure. Very small droplets expelled or atomized into the air by sneezing constitute mists containing micro-organisms that become air contaminants. Fogs are limited by some clarifications to airborne drop CLASSIFICATION OF AIR CONTAMINANTS Air contaminants may be classified in the following groups: (1) dust, fumes, and smokes which are solid particulate con taminants, (2) mists and fogs which are liquid .particulate ' contaminants, and (3) vapors and gases which are nonpar- - ticulate contaminants. . *' Dust, Fumes, and Smokes lets formed by condensation from the vapor state. This arbi trary distinction between mist and fog is of minor impor tance, as both terms are used to indicate the particulate state of airborne liquids (occasionally termed aerosols). Fog noz zles are so named because of their ability to produce extra fine droplets as compared to the oust from ordinary spray devices. Tlie highly volatile nature of some liquids quickly reduces their airborne droplets from the mist to the fog range, and 'eventually to the vapor phase until the air be- Dusts arc solid particles projected into the air by natural forces, such aswind, volcanic eruption, or earthquake, and by mechanical-processes, such as crushing, grinding,'milling, comes saturated' with that liquid. Many droplets in fogs or clouds are microscopic- and submicroscopic in size, and may be conceived as.the transition state between the larger mists drilling, demolition, shovelling, conveying, screening, bagging, and the vapors. ' and sweeping. Some of these forces produce dust from larger . masses, while others simply disperse materials that are &1- ! Vapors and Gases . ready pulverized. Generally, particles are not called dust un Vapors and Gases are nonparticulate air contaminants. less they are smaller than about 100 microns. Dusts may be of Vapors are the gaseous phase of substances that are either mineral type, such as rock, ore; metal, sand; vegetable, such liquid'or solid in their commonly known state, examples be as grain, flour, wood, cotton, pollen; or animal, such as wool, ing gasoline, kerosine, benzene, carbon tetrachloride, mercury, hair, silk, feathers, leather. iodine, camphor. Vapors may be changed to the solid or 73 'S . . 74 CHAPTER 7 1959 Guide Air Contaminants. 75 liquid form by increasing the pressure, decreasing the tem perature, or applying both processes simultaneously. They are removed from the air by condensation with less difficulty thn are the gases. Gases are normally formless fluids which tend to occupy a space or enclosure completely and uniformly at ordinary temperatures and pressures. The following substances qualify as gases: oxygen, nitrogen, carbon dioxide, carbon monoxide, hydrogen, ammonia, sulfur dioxide. Gases, likewise, may be solidified or liquefied by the proper control of temperature and pressure. The preceding classification is not suitable for the airborne living organisms, which range in size from the submicroscopic viruses to the largest pollen grains, not considering the small est insect life. Bacteria range from about 02 to 5 microns in size, fungus spores from 1 to 10 microns, and pollen from 5 to 150 microns. ' Table 1 .... Relation of Screen Mesh to Partide Size U. 5. Standard mm Hoomal oeve opening in 400 325 200 140 100 60 35 37 44 74 105 149 250 500 18 1000 Microscopic examination of screened dust indicates that the average diameter of a sample of irregular particles may be substantially larger than the openings of the screen through which it has passed, if the particle shapes deviate consider ably from the spherical form* The smallest dimension of many such particles will correspond to the maximum per missible distance between the wires of commercial screens made to ASTM Standard Specifications. Screening does not give sharp separation into sire groups, and accordingly, such a classification is statistical rather than absolute. SIZES OF AIRBORNE PARTICLES AIR POLLUTION BY SMOKE, ASH, AND CINDERS Compiled by W. C. Frank 4od copyrighted, used by perminioa. Fig. 1 . . Sizes and Characteristics of Airborne Particulate Matter- Fig. 1 is a graphic tabulation of the properties of airborne solids and liquids arranged according to sire on the micron scale. There are 25,400 microns in 1 inch. ' Particles larger than 10 microns are unlikely to remain suspended in air currents of moderate strength, but settle out by gravity at speeds dependent upon the shape, are and spe- ' cific gravity of the particle, wind velocity, orientation of the collecting surface, and topography. These larger particles are of major interest to the engineer in the solution of nui sance problems, but it is usually the smaller particles, or those below 10 microns, that remain'in the air long enough to'be of hygienic as well as economic significance. Industrial dust particles are predominantly-of the order of 1 micron in sire. Tremendous numbers are also present in the submicroscopic range below 0.5 micron, but those below 0.1 micron are not believed at present to be of practical im portance, possibly due to their exceedingly small mass in com parison with the balance of airborne matter. In fact, particles this small may become the permanent atmospheric impurities that have little, if any, opportunity of settling because of the continual motion imparted to them by air currents and the molecular activity of gases (Brownian Movement). The survey1 of atmospheric pollution in 14 American cities conducted from 1931 to 1933 indicated the average size of out door dust particles to be 0.5 micron, as collected by the Owens jet dust counter and measured under the microscope. Inability of the light field microscope to reveal particles in the 0.1 micron vicinity may have influenced the determination of average particle sire. - The lower limit of particle size visible to the naked eye cannot be stated definitely. It depends not only upon the in dividual eye, but also upon the shape and color of the parti cle, intensity and quality of the light, and nature of the back ground or opportunity for contrast. Under ideal conditions a particle of 10-micron size might be recognized, while under less favorable conditions it may be impossible to distinguish a particle smaller than 50 microns. The lower limit of visi bility probably ranges from 10 to 50 microns. Ousts, powders, and granular materials are frequently classified by reference to the sire of screens used for separa tion. Particles above 40 microns are said to be the screen sizes and those below, the subsereen or microscopic sizes. Ap- proximate or theoretical sizes of particles corresponding to the mesh scale of the U. S. Standard Sieve Series are given in Table 1. Total airborne solids settling in urban areas are usually reported as soot fall in tons per (square mile) (month). Such Table 2 .... Dust Concentration Ranges loeofioo - G/oint per 1000 Co H* MiUigroan per Cubic Meier Rural and suburban districts. Metropolitan districts............. Ordinary factories or work rooms ........................................ Excessively dusty factories Minimum explosive concen- 0.02-0.2 0.04-0.4 0.1-2.0 0.2-4.0 4-400 4000-200,000 0.05-0.5 . 0.1-1.0 0.2-5.0 0-5-10 10-1000 10,000-500,000 * 1 grain per 1000 eu ft -- U milligrams per cubic meter. 1 ib per cubic loot -- 1 gram per liter -- 1000 cam* per cubic meter- data published for the cities in this country range from 20 to 200 tons per (square mile) (month). To the air-condition ing engineer this information may indicate the effectiveness of smoke abatement or fuel combustion control methods in his locality, but it does not provide a suitable index of the suspended dust that air cleaners in a ventilating system are expected to capture.1, *1 Gravimetric or weight data of the type given in Table 2 are preferable. In some cases airborne particle counts may be necessary, as for pollen, bacteria, spores, and insoluble dusts causing illness or lung disease. Dust concentrations by weight cannot be converted readily to concentrations by particle count because of the variability of particle size, shape, and specific gravity, and the inherent characteristics of dust counting and weighing procedures. One milligram of dust per cubic meter of air may represent dust counts from 1 million to 100 million particles per cubic foot of air (light field microscope technic) according to the size distribution of the airborne dust sample. Information of this type for a specified application is best obtained by simulr taneous sampling for both counting and weighing and noting carefully at the time- all factors that might affect the repro ducibility of the count-weight ratio. .. _ Smoke Abatement and Air Pollution Control Successful abatement of atmospheric pollution caused.by smoke requires the combined efforts of the combustion engi- 76 CHAPTER 7 1959 Guide neer, industrial executive, public health officer, city planning commission, and the community at large. Electrification of industry and railroads, increases in the use of domestic oil and gas furnaces, ami segregation of industrial districts arc gradually providing effective aid in the solution of this prob lem. In the large cities where nuisance from smoke, fly-ash, and cinders is more serious, limited areas obtain some relief by the use of district heating. (See Chapters 33, 34, and 35 for further discussion on fuel-burning technic.) , Many present ordinances limit the Qumber of minutes in any one hour that smoke of a specified density (determined by comparison with a Ringelmann Chart which is described in Chapter 44) may be discharged. - There is now considerable interest and activity in the con trol of air pollution factors in addition to smoke. Difficulty in the establishment of acceptable criteria for certain cor rosive and irritant gases, such as fluorides and the oxides of sulfur and nitrogen discharged with the gases of combustion, and the frequently complicated technical and economic prob lems encountered in control, have delayed the drafting and enforcement of legislative measures. Recent reports of an in creased incidence of diseases, such as pneumonia and lung cancer, in areas high in certain air contaminants, require further critical investigation before acceptance. The values finally adopted will undoubtedly be lower than the MAC (Maximum Allowable Concentration) limits for use in in dustry, because the exposure is continuous compared with the 8-hour day, 5- or 6-day week upon which MAC values are based, and because the exposed population contains individ uals with greater variation in age and health status. In foggy weather, or during an inversion of atmospheric conditions, accumulation of gaseous contaminants may.cause irritation of eyes, nose, and respiratory passages, and possi bly cause even.more serious physiological effects. The Meuse Valley fog disaster (Belgium 1930) and the Donors smog (Pennsylvania 1948) are classic examples in the history of gaseous air pollution. In both instances it is believed that irritant gases, principally from industrial plants, accumu lating during periods of exceptionally prolonged meteoro logical inversion and fog, contributed to the illness of many persons, and to the death of some who were especially sus ceptible. ' Absorption of Solar Radiation Absorption of solar ultra-violet light by smoke and soot is recognized as a health problem in many industrial cities. Measurements of solar radiation in Baltimore* by actinic methods demonstrated that ultra-violet light intensity in the country was 50 percent greater than in the city. In New York City1 a loss as great as 50 percent in visible light was found by photoelectric measurements. ODOR NUISANCE. A problem companionate with smoke abatement is the control of odor nuisance in the neighborhood of industrial plants discharging noxious or offensive air contaminants. Community planning and zoning will avoid much of the diffi culty in the future, but meanwhile many industrial cities must . resort to corrective measures by requiring installation of air clftaning devices, alteration of manufacturing processes, or termination of the offensive operation in residential or com mercial districts. Control of outdoor odor nuisance is especially troublesome because of the extremely minute quantities of contaminant that are capable of offending through a wide area. New indus trial chemicals with strange or unfamiliar odors tend to re ceive more attention from the neighborhood than the custom ary odors generated by well-known processes and. raw materials. Methods of odor control currently in use include charcoal adsorption, scrubbing towers and air washers, chlo rination, condensation, masking, passage of the odorous air through combustion chambers, dispersion through a tali stack, and best of all, substitution of less offensive materials whenever possible.*- * " u Control of air quality within buildings ventilated for hu man occupancy is discussed in Chapter 6. Tobacco smoke odors, cooking odors, and body odors are air contaminants of the nuisance type which now command a decisive posi tion in the standards of air quality for indoor comfort. How ever, the engineer will find, at times, that odors originating outside buildings in industrial or business districts may de termine the kind and capacity of equipment he must provide for a high quality air-supply installation. INDUSTRIAL AIR CONTAMINANTS Many industrial processes .are sources of contaminants. Their control is an important function of the ventilating or air-conditioning engineer, because the atmosphere within buildings is the medium whereby such finely divided matter is dispersed and transported from the source to remote loca tions where it may cause property damage, nuisance, fire, ex plosion, disease, and even death. - Tables 3, 4, and 5 give maximum allowable concentration values for many industrial air contaminants. Some of these values have been proposed by ASA Sectional Committee Z37 on Allowable Concentrations of Toxic Dusts and Gases, and others by the Committee on Threshold Limits of the Ameri can Conference of Governmental Industrial Hygienists. The values have-been adopted by the American Conference of Governmental Industrial Hygienists and by many of the official industrial hygiene agencies. '' It must be emphasized -that these limits in the great ma jority of instances are only suggested maximum working levels since they are estimates, based in.many cases upon in complete environmental and medical studies. Where there is agreement between the ASA Standard Z37 and ACGIH values, reliability of the ASA Standard is increased. The val ues are not fixed, but are subject to revision; upward or downward, with the development of new information. There is by no means complete agreement regarding these values among responsible industrial hygienists. . In applying these guide limits, the following factors must be . considered: 1. The duration of exposure is 8 hr a day for 5 or 6 days a week. .. 2. The measurements are indicative of the concentration in the breathing zone of the exposed person. . 3. The MAC is usually accepted as the average exposure value when the upper limits do not greatly exceed the MAC value. For example, it cannot be' assumed that if 100 ppm is considered safe for 8-hour exposure, that 800 ppm for one hour will .be permissible. 4. Two substances with similar MAC values may be quite different as to physiological effects at other concentrations. In one instance the selection of a limit may be predicated upon a discomfort factor, with a wide margin of safety before systemic effects would be encountered, while in another case the value represents an appreciable fraction of the concentra- Air Contaminants 77 Substance Table 3------ Moximum Allowable Concentration of Gases and Vapors ASA Thrstbefd limit Vetoes ' ACGfH* 19S8 . onU MAC glot m or b * ppmb oz/IOOO OJ ft ASA ThreiMd limit VaHms Stand* ACGitt* IVS9 MAC ppm* by g/eu a or Oi/IOOO Ammonin 200 10 1000 0.5 20 100 200 100 0.360 0.025 0.020 2.400 0.0012 0.012 0.015 0.012 0.070 1.050 0.360 Benzyl chloride___ .................... 100 25 Butadiene (1,3-butadiene).... Butanone (methyl ethyl keButvl acetate (n-butyl ace- Butyl alcohol (n-butanol)... 1000 250 200 100 Butyl eellosolve (2-butoxy- Cellosolve (2-ethoxyethanol).. Cellosolve acetate (2-ethoxy- 50 5000 20 20 100 100 25 200 100 ft"0007 O'080 0.005 0.007 2.200 0.300 0.015 0.240 9.000 0.060 0.110 0.160 0.740 0.540 Chlorobcnzene (monochloroChlorofonn (trichlororaethane) 1-Chloro-l-nitronronaiM* Chloroprene (2-chlqro-l,3-bu- Diacetone alcohol (4-hydroxy4-methy!-2-pentanone)... Dichlorodifluoromet.hnnp 1,2-Dichloroethaoe (ethylene dichloride^ * Dichloromonofluoromethane. . 1,1 -Dichloro-1 -nitroethane.... 0.1 75 100 20 0.0004 0.350 0.490 0.100 25 400 100 100 400 400 0.05 0.090 0.022 0.410 0.400 1.350 0.690 0.0003 50 0.1 50 000 100 0.240 0.300 4.95 0.400 100 200 15 1 000 10 0.400 0.790 0.090 4.200 0.060 Aisuin - Amman Conference of Governmental Industrial Beprinted bypennbewn from AHA ArcUma a/ hUuttriol HtoUk. 857, VoL 18, pp. tti-Jtt. b of repor or gae per million parts of air by volume. . Diehlorotetrafluoroethane___ * Diethylamine.............................. Difiuorodibromomethane .... Diisobutyl ketone..................... Dimethyl aniline (N-diraethyl- aniiine)..................................... Dimcthylsulfate......................... Dioxane (diethylene dioxide). Ethyl acetate.............................. (x) Ethyl acrylate............................ Ethyl alcohol (ethanol).......... Ethylamine.................................. Ethyl benzene............................ Ethyl bromide.. Ethyl chloride!. Ethyl ether....... Ethyl formate... Ethyl silicate.............................. Ethylene chlorhydrin.............. Ethylenediamine....................... Ethylenedibromide (1,2-di- bromoethane)......................... Ethylene imine.......................... Ethylene oxide.................. Fluorine................................ Fluorotrichloromethane.. Formaldehyde.................... (x) Furfural................................ Gasoline........................................ Heptane (n-heptane)............. Hexane (n-hexane)................... Hexanone (methyl butyl ke tone) .......................................... Hexone (methyl isobutyl ke tone).......................................... Hydrazine.................... Hydrogen bromide___ Hydrogen chloride___ Hydrogen cyanide. ... Hydrogen Buoride.... Hydrogen peroxide, 9( Hydrogen selenide___ Hydrogen sulfide......... * Iodine.............................. Isophorone..................... Isopropylamine.......................... * Mesityl oxide.............................. Methyl acetate........................... Methyl acetylene...................... (x) Methyl acrylate........................ Methyl alcohol (methanol)... Methyl bromide........................ Methyl eellosolve (2-methoxy- ethanol).................................... . Methyl eellosolve acetate (etnylene glycol mono methyl ether acetate)............ Methyl chloride........................... ' Methyial (dimethoxymethane) 100 400 25 1000 25 200 200 1000 400 100 25 5 50 0.1 1000 500 500 500 7.00 0.075 0.860 0.290 0.025 0.005. 0.360 1.400 0.100 1.900 0.045 0.870 0.890 2.600 1.200 0.300 0.850 0.016 0.030 0.190 0.009 0.090 0.0002 5.600 0.006 0.020 2.000 2.000 1.80 04i0 5 10 3 1 0.05 20 0.1 25 200 1000 0.0013 0.017 0.007 0.011 0.002 0.0014 0.0002 0.030 0.001 0.140 0.012 0.100 0.610 1.650 0.035 100 1000 0.210 3.100 (z) Three veluee appeared in ACGIH tentative list for 19M * These items include ehsncee made by ACGIH on Thresbo JfflTta tn IMS, 78 CHAPTER 7 1959 Guide Table 3 .... Maximum Allowable Concentration of Gases and Vapors (Conc/uded) Substance ASA hroshold Lindt Valuer Stand- ACGIH* 1958 MAC PptPbr PP"b g/ev a or oi/lOOO cu ft Methyl chloroform (1-1-1 tri- Methyl isobutyl carbinol Methylene chloride (dichloro- Pentane.......................................... Pentanone (methyl propyl kePerchlorethylene (tetra- chloroethylene)........................ Phenylhydrazine......................... Phosgene (carbonyl chloride).. Propyl alcohol (isopropyl alPropyl ether (isopropyl ether). Propylene dichloride (1,2- Styrene monomer (phenyl- 1,1,2,2-Tetrachloroethane... Trifluororoonobromomethane Vinyl chloride (chloroetbylene 500 2.700 2.000 0.470 0.460 0.250 0.100 1.750 200 0.800 500 2.000 0.001 0.000007 10 0.025 0.006 0.005 0.310 0.009 0.005 0.250 1000 0.180 0.030 2 350 0.0002 2.950 0.700 200 5 l 0.05 1.350 0.019 0.022 0.004 0.00007 0.840 400 0.980 500 2.100 0.350 0.060 0.030 0.0004 0.1 0.0005 2.90 400 100 1000 5. 200 . 200 200 200 1000 0.420 0.013 6.000.. 0.006 0.00025 0.060 0.035 0.590 0.008 0.750 0.022 1.050 6.100 0.560 500 1.30 200 0.870 tion which may be associated with severe and irreversible injury. 5. These values are upper limits; it is desirable to operate well below the levels if the engineering and economic factors permit. The prudent engineer will incorporate a reasonable margin of safety in his estimates of ventilation capacity. In Table 3, Column 1 lists the ASA Sectional Committee Z37 MAC values; Column 2, those of the ACGIH Commit tee on Threshold Limits. Column 3 gives the value in grams per cubic meter or ounces per 1000 cu ft for the corresponding ACGIH limits. In Table 4, Columns 2 and 3 are respectively the MAC values from the ASA and ACGIH Committees. In Table 5, the MAC values for industrial dusts as given were obtained from data of the ACGIH Committee on Threshold limits. ACGIH limits for either gamma or Roentgen radiations are 0.3 roentgens per week. Information on the properties and effects, with respect to health, of specific industrial air contaminants is available in publications listed at the end of this chapter. FLAMMABLE GASES AND VAPORS Adequate ventilation is a primary requirement for mini mizing the hazard of fire or explosion due to gases and vapors. The need for good ventilation is not removed by the use of other precautions, such as the elimination of known ignition sources, segregation of hazardous operations, adoption of safe building construction, and installation of automatic alarms. Some safety engineers regard overventilation of ah operation employing flammable liquids as a legitimate oper ating charge for the privilege or necessity of using a danger ous process. However, it is not possible to apply a reasonable safety factor to the ventilation estimate without considera tion of the concentrations of gases or vapors that approach the danger point. Safety engineers prefer to limit the concen tration to V\ or Yb of the lower explosive limit, and this fact should be given full weight in determining the capacity and design of ventilating equipment. Rarely should consideration be given to operation above the upper explosive limit in the open areas of buildings or rooms--even though unoccupied-- because the danger of temporary drop of gas concentration to a point within the explosive range is too great. Ability of a flammable liquid to form explosive mixtures is determined largelyby its vapor pressure, volatility, or rate of evaporation. Flash point is a convenient method of ex pressing this property in terms of the temperature scale. It may be defined as the temperature to which a combustible liquid must be heated to produce a flash when a small flame is passed across the surface of the liquid. The higher the flash point, the more safely can the liquid be handled. Liquids with flash points under 70 F should be regarded as highly flammable. Upper and lower limits of flammability of gases and vapors, and the flash points of the corresponding liquids are given in Table 6. . Methods for estimating the flammable limits of mixtures of gases or vapors must be applied with caution; the reader is referred to other publications for this information.1*- Design of equipment for the control of combustible anes thetics is outlined in Chapter 8. Construction of equipment for handling air containing flammable substances, or operat ing in atmospheres so contaminated, is discussed in Chapter 52. It is customary to report the concentrations of flammable Air Contaminants 79 Table 4 .... Limits for Toxic Ousts, Fumes, and Mists ASA Stand- MAC, Hired)old limit Voluet, ACGIH 1958 q/cb o* Aldrin (1,2,3,4,10,10-bexachloro-l,4,4a, 5,8,8ahexahydro-l %4,5,8-dimethaDcmaphthalene)................... ................ Animate (ammonium sulf&mate).............. Antimony......................................................... (x) ANTU (alpha naphthyl thiourea)........... 0.00025 0.015 0.0005 0.0003 Arsenic................................................................. Barium (soluble compounds)....................... Cadmium oxide fume..................................... (x) Calcium arsenate............................................. Chlordane (1,2,4,5,6,7,8,8-octachloro- 3a,4,7,7a-tetrahydro-4,7-metbanoindane)................................................. 0.0005 0.0005 0.0001 0.0001 0.002 (x) Chlorinated camphene (60%)............ ......... Chlorinated diphenyl oxide.......................... Chlorodiphenyl (42% chlorine)................... (x) Chlorodiphenyl (54% chlorine)................... Chromic acid and chromates (as CrO). . 0.0001 0.0005 0.0005 0.001 0.0005 0.0001 Crag herbicide (sodium 2-[2,4-dichlorophenoxy] ethanol hydrogen sulfate) :. Cyanide (as CN).............................................. 2,4-D(2,4-dichlorophenoxyacetic acid)... (x) DDT (2,2-bis(p-chlorophenyl)-l,l,l,trichloroetb ane.............................................. 0.015 0.005 0.010 0.001 . Dieldrin (1,2,3,4,10,I0-hexachioro-6,7epoxy-i ,4,4a, 5,6,7,8,8a-octahydro1,4,5,8-diroethanonaphthalene)......... (x) Dinitrobenzene.................................................. Dinitrotohiene................................................... Dinitro-o-cresol................................................. 0.00025 0.001 0.0015 0.0002 EPN (O-ethyl O-p-nitrophenyl thiono- benzenephospoonate).............................. (x) Ferbam (ferric dimethyl dithioc&rbamate) Ferrovanadium dust........................................ Fluoride............................................................... 0.0005 0.015 0.001 0.0025 Hydroquinone.................................................. . Iron oxide fume.............................................. Lead.................................................................... (x) Lead arsenate.................................................. . Lindane (hexachlorocyclohexane, gamma isomer)....................................................... . Magnesium oxide fume................................ Malathion (0,0-dimethyl dithiophosphate of diethyl mercaptosuccinate). Manganese........................................................ 0.006 . Mercury...................................... ...................... 0.0001 Mercury (organic compounds).................... Methoxyehlor (2,2-di-p-methoxyphenyl- 1,1,1-trichloroethane)............................ Molybdenum . ' (soluble compounds)................. ................. (insoluble compounds)............................... (x) Nicotine............................................................ Parathion (0,0-diethyl O-p-nitrophenyl thiophosphate)........................................ PentachloronaphthaJene............................... Pentachlorophenol.......................................... Phosphorus (yellow)...................................... Phosphorus pentachloride Phosphorus pentasulfide.. Picric acid........................... - Pyrethum.............................. (x) Rotenone .............................. 0.002 0.015 0.0002 0.00015 0.0005 0.015 0.015 0.006 0.000] 0.00001 0.015 0.005 0.015 0.0005 0.0001 0.0005 0.0005 0.0001 0.001 0.001 0.0001 0.002 0.005 Table 4 .... Limits for Toxic Ousts, Fumes, and Mists (Concluded) Substance ASA Stond- MAC, Tbretbofd Limit Vofues, ACGIH 1958 g/ew * TEDP (tetraethyl dithionopyrophos- . Tetryl (2,4,6-trinitropbenyimethyInitra(x) Thiram (tetramethyl thiuram disulfide)... 0.0001 0.0001 0.002 0.00015 0.001 0.0002 0.0001 0.0015 0.005 0.0001 0.0015 0.00005 0.00025 (x) Warfarin (3-fet acetonylbenzyl]-4*hy' droxycoumarin)........................................ 0.0005 0.0001 0.0005 0.015 0.005 Grama of dust, fume, or mist per eubio meter of air. . (x) These values appeared on the ACGIH tentative tat, far 1956. Bsdicoetivity: For permissible concentration* of radiobotopa in sir, see Maximms* PtrvaxtHU Amount* of Reiitdtattrpt* in Uu Huum* Bait and Maxi mum PtrmitoibU Concentration* in Air and Water. Handbook S3, D. S. Depart ment of Commerce. Nations] Bureau of Standards, March, 1553. In addition, see PtmtitribU Dot* from External Sowta ef Ionian^ Radiation, Handbook G9, U. S. Department of Commerce, National Bureau of Standards, September 54, 1954. . Table i vaiuee reprinted by permisrion from AMA Aroldtot of Industrial Health, September 1857, Vol. 16. pp. 281-185. No channel were made by ACGIH Committeeon Threshold limits at 1958 meeting. - - Table 5 .... limits for Mineral Dusts Threshold Unit Vafwer ACGM 1958 mppcf Aluminum oxide........................... .....Asbestos.............. ........................... Cement, Portland........ .1 Dust (nuisance; no free silica) Mica (below 5% free silica)............... Silica--high (above 50% free SiO). Silica--medium (5 to 50% free SiOj) Silica--low (below 5% free SiOt). . . Silicon carbide.................... ......... .. Soapstone (below 5% free'StOi) Talc.................................................... 50 5 50 50 20 5 20 50 * mppcf--million particle* per cubic foot of air, standard light held count. Table 5 vahiea reprinted bypermission from AMA AnJatn* of Industrial UmiltL, September 1957, Vol. 16, pp. 561-56S. No were by ACGIH 'Committee bn Threshold Limits.in 1956. X 80 CHAPTER 7 1959 Guide Table 6 .... Approximate Limits of Flammability of Single Gases and Vapors In Air at Ordinary Temperatures and Pressures* Gas or Vapor limit Pimnf by Volume Upper l/mrf Percent by Volume CJosgd Cop* NBFU Ftadi CIcmiPoint fico* b'on* hgit Acetaldehyde.......................... Acetone.................................... Acetylene................................. Aliyl alcohol........................... Ammonia.................................. Amyl alcohol.......................... Amyl chloride........................ Amylene................................... Benzene (benzol).................. Benzyl chloride...................... 4.0 2.5 2.5 2.5 15.5 1.2 1.6 1.6 1.3 57 12.8 80 26.6 7.7 6.8 -17 0 70 100 12 I I II III I II Butane....................................... Butyl acetate......................... Butyl alcohol.......................... Butyleae.................................. Carbon disulfide.................... 1.8 3.4 1.4 15.0 84 III 1.7 2.0 9.7 1.2 50 -22 I Carbon monoxide.................. Crotonaldehyde..................... Cyclohexane............................ Cyclopropane......................... Decane...................................... 12.5 2.1 1.3 2.4 0.67 74.2 15.5 8.4 10.5 2.6 55 II .1 I 115 III Dichloroetbylene (1, 2).... Diethyl setenide.................... Dioxane.................................... Ethane.............................. . Ether (diethyl)...................... 9.7 12.8 57 11 2.5 2.0 22.2 54 11 3.1 12.5 1.8 36.5 -49 I Ethyl acetate......................... Ethyl alcohol.......................... Ethyl bromide.. ].......... Ethyl celloeolve..................... Ethyl chloride........................ 2.2 11.5 28 II 3.3 19.0 54 II 6.7 11.3 2.6 15.7 1(M III 4.0 14.8 -58 I Ethylene.............. -................... Ethylene diehloride.............. Ethyl formate.-...................... Ethyl nitrite........................... Ethylene oxide....................... 2.7 28.6 6.2 15.9 56 II 2.7 16.5 -4 I 3.0 50 -31 I 3.0 80 Furfural (125 C).................... Gasoline (variable).............. Heptane.................................... Hexane...................................... Hydrogen cyanide................ 2.1 1.4-1.5 7.4-7.6 1.0 6.0 1.2 6.9 5.6 40.0 140 -50 25 -15 III I 11 I Hydrogen................................. Hydrogen sulfide.................. Illuminating gas (coal gas) Isobutyl alcohol.................... Isopentane............................... 4.0 74.2 4.3 45.5 5.3 33.0 1.7 1.3 82 III Isopropyl acetate.................. Isopropyl alcohol.................. Methane................................... Methyl acetate....................... Methyl alcohol....................... 1.8 7.8 43 II 2.0 - 53 II 5.0 15.0 3.1 15.5 14 I ' 6.7 36.5 52 11 Methyl bromide..................... Methyl butyl ketone............ Methyl chloride..................... Methyl cyclohexane.............. Methyl ethyl ether............... 13.5 14.5 1.2 8.0 ' ' 8.2 18.7 1.1 25 II 10.1 I Methyl ethyl ketone............ Methyl formate..................... Methyl propyl ketone................... Natural gas (variable).................. Naphtha (benzene) .............-..... 1.8 5.0 1.5 4.31.1 9.5 22.7 .. 8.2 13.5 6.0 30 -2 20-110 II I III Table 6 .... Approximate limits of Flammability of Single Gases and Vapors In Air at Ordinary Temperatures and Pressures* (Conrlur/orf) Got or Vapor limit Prc*nl by VoJuao Gppor Oomf Cup* NBFU fercmtl Flash Point Vofuroo Fdirtn- lion* mi Naphthalene..................................... Nonane............................................... Octane................................................ Paraldehyde...................................... Pentane.............................................. 0.9 0.83 0.95 1.3 1.4 Propane.............................................. Propyl acetate................................. Propyl alcohol................................. Propylene.......................................... Propylene dichloride...................... 2.1 1.8 2.1 2.0 3.4 Propylene oxide............................... Pvridinc............................................. Toluene (toluol).............................. Turpentine........................................ Vinyl ether........................................ 2.0 1.8 1.3 0.8 1.7 Vinyl chloride.................................. Water gas (variable)...................... Xylene (xylol)................................. 4.0 6.0 1.0 2.9 3.2 7.8 10.1 8.0 13.5 11.1 14.5 22.0 12.4 7.0 27.0 21.7 70 6-0 176 III 88 111 56 11 58 II 59 11 60 II 74 III 40 11 95 111 63 11 * Adapted front: Firt and Erplasien Hazards of Combostibls Goat* gad Vojwrt, by G. W. Joans; Chapter IS. Industrial Hnisas and Toticolggg, edited by F. A. Patty (Intersctcace Publisher*, ISIS); Pnpsxtiss a}FtammabU Liquids, Gases and Solids (Associated) Factory Mutual Fire lot. Cos.', January (IMS); and National Pits Codes for PinaineM* Liquids, Gases, Chemicals and Exjdosises--IMS (Na tional Fire ProtectionAssociation): * Closed cup reieza to the equipment used id flash point determinations * From Standards for Stonge, Handling and Vee of Flammable Liquids (Na tional Board of Fire Underwriter*, No. 30, July 1U4). gjses or vapors in percent by volume, or volume percent. Comparison with concentrations on the part per million scale used in chemical, medical, or industrial hygiene literature is readily made by the conversion: 1 percent = 10,000 ppm (parts of contaminant per million parts of air, by volume, or in other words, cubic feet of contaminant per million cubic feet of air). It will be noted in Table 6 that nearly ail of the substances listed have lower explosive limits above 1.0 per cent, while the maximum allowable concentrations for gases and vapors in Table 3 are below 1000 ppm or 0.1 percent in most cases. Therefore, control of toxic or injurious vapors to levels below their maximum allowable concentrations for health usually requires much more effective ventilation than for the prevention of a fire hazard. COMBUSTIBLE DUSTS . A dust explosion is essentially a sudden pressure rise caused by the very rapid burning of airborne dust. The primary ex plosion often originates from a small amount of dust' in sus pension exposed to a source of ignition and the pressure and vibration it creates may be sufficient to dislodge large accu mulations of dust on horizontal ledges or surfaces of the building and equipment, thereby creating a secondary .ex plosion of great force. Thus the air-conditioning engineer is involved for two reasons: (1) to obtain a movement of-dustladen air into exhaust hoods or openings, and through venti lating or pneumatic conveying ducts, in a manner that will prevent accumulation of highly flammable dust at points Air Contaminants 81 where it could ignite inside the equipment; and (2) to so de- i^ign process ventilation as to prevent the escape of dust which might settle on horizontal surfaces and become a po tential source of disaster at some distance from the dusty operation. (See Chapter 52.) Intensity of a dust explosion depends upon: chemical and thermal properties of the dust; particle size and shape; con centration in air; proportion of inert dust in the air; moisture content and composition of the air; size and temperature of the ignition source; and degree of dispersion of the dust cloud. Investigatidns on the explosibility of dusts require determina tion of the maximum pressure developed during explosion of a known air concentration, as welt as determination of the rate of pressure rise. Investigators frequently experience difficulty in obtaining dust suspensions of uniform dispersion, and this should be kept in mind when comparing results from several sources.14 Minimum explosive concentrations of airborne dusts al ready tested range from 0B1 to 0.5 oz per cubic foot, or 10 to 500 grams per cubic meter of air. Maximum pressures gen erated have been reported as high as 500 psig, although they are more likely to be of the order of 50 psig. Investigations on the flammable characteristics of dusts are currently made at 0.1 and Oh os per cubic foot.1*'" . ATMOSPHERIC POLLEN Properties of pollen grains discharged by weeds, grasses, and trees and responsible for hay fever, are of special interest to designers of air cleaning equipment (see Allergic Dis orders in Chapter 8, and Air Cleaning, Chapter 24). Whole grains and fragments transported by the air range chiefly between 10 and 50 microns in size, but some have been meas ured as small as 5 microns, and others over 100 microns in diameter. Ragweed pollen grains are fairly uniform in size within the range of 15 to 25 microns. Pollen grains can be removed from the air more readily than the particles of dust prevalent in outdoor air or produced by dusty processes, since the latter predominate in the range of 0.1 to 10 microns in size. - Most grains are quite hygroscopic and therefore vary in weight with the humidity.' Illustrations and data on individ ual pollen grains are available in the botanical literature.*' ** " Geographical distribution of plants known to produce hay fever is also recorded.**" The quantity of pollen-grains in the air is generally esti mated by exposing an adhesive-coated glass plate outdoors for 24 hr, and then counting calibrated areas under the micro scope. Methods are available for determining the number of grains in a measured volume of air,*'*1'* but-their greater accuracy has not caused them to replace the more ample - gravity slide method used for most pollen counts. Counting technics vary somewhat, but the daily pollen counts reported in local newspapers during the hay fever season usually repre sent the number 'of grains found on 13 sq cm of a 24-hr gravity slide. Hay fever sufferers may notice the first symptoms when the pollen count is 10 to 25, and in some localities the maxi mum figures for the seasonal peak may approach 1000 for a 24-hr period, depending upon the sampling and reporting methods of the laboratory. Translation of gravity counts by special formulas to a volumetric basis, or the number of grams per cubic yard or per cubic foot of air, is unreliable because of the complexity of the modifying factors. When such information is important, it is best obtained directly by a volumetric instrument. The number of pollen grains per cubic yard of air evidently varies from 2 to 20 times the number found on l sq cm of a 24-hr gravity elide, depending on gram diameter, shape, specific gravity, wmd velocity, humidity, and physical placement of the collecting plate* * * . AIRBORNE BACTERIA Study of the occurrence and significance of micro-organisms in the atmospheres of the indoor world is absorbing the energies of a substantial number of physicians, bacteriologists, aerobiologists, physicists, public health workers, engineers, and hospital personnel. Some data are available on the types and quantities of bacteria found in a variety of spaces, but it is not possible at present to use this information as a con clusive index of the potential health hazard of a given en vironment. The reported number of airborne organisms may vary from 1 to 1CO0 per cubic foot of air, influenced some what by the method of testing." Many are attached to the dust particles present in the air. Where it seems advisable or desirable to control the bac terial content of rooms, public conveyances, or buildings, highly effective methods are available (see Chapter 8), and their extended use may do much to assist the workers in this field in accumulating the necessary maa of evidence that will decide the practical value of air sterilization for the con trol of communicable disease. It is now well established that ultra-violet radiation is feasible for the protection or preserva tion of pharmaceuticals, cosmetics, and food products. - RADIOACTIVE AIR CONTAMINANTS" Radioactive air contaminants are physically similar to ordinary industrial and chemical plant contaminants. They differ from ordinary contaminants, however, in that they may be highly toxic when ingested and may present a direct radiation hazard when accumulated in appreciable quantities. Another factor which must be considered in the filtration of these materials is the possibility of their being concentrated in plant and animal life in the area of contamination. Con centrations resulting from absorptions by -plants and sub sequent feeding of animals in the magnitude of several thou sand times, is not unusual. Tolerances for radioactive contaminants have been established and are under continu ing study and'review. Guidance in regard to tolerance levels for discharge of contaminated.air in different types .of lo calities can best be had from the classified literature which is available through proper clearance procedures. REFERENCES 1 J. E. Ives et al: Atmospheric Pollution of American Cities for the Years 19S1 to 1053 (US. Public Health Service Bulletin No. 224, March 1036). *J. M. DallaValle: Micrometries, The Technology of Pine Particles (Pitman Publishing Corporation, New York, 1943). * A. C- Stern: Atmospheric pollution due to smoke (Heating and Ventilating, May 1945). A. C. Stem: Atmospheric pollu- tion due to dust and cinders (Heating and Ventilating, July 1945). 4 J. Siegel and B. Feiner: Sootfall studies for New York City (ASHVE Journal Section, Heating, Piping and Air Condition ing, September 1945, p. 495). * A. C- Stem: The use of fuel consumption and equipment data in the abatement of atmospheric pollution (ASBVE Journal Section, Heating, Piping and Air Conditionina. Aueust 1945, p. 447). - J. H. Shrader, M. H. Goblentx, and F. A. Korff: Effects of atmospheric pollution upon incidence of solar ultra-violet light (American Journal of Public Health, Vol. 19, 1929, p. 7). 1 J. E. Ives: Studies in Illumination III: A Study of the Lose y ' 82 CHAPTER 7 1959 Guide of Light Due to Smoke on Manhattan Island (U. S. Public Health Service Bulletin No. 197, June 1930). 'F. M. Stead: Study and control of industrial atmospheric pollution nuisances (American Journal of Public Health, Vol. 35, May 1915, p. 491). * J. M. DailaValle and H. C. Dudley: Evaluation of Odor Nui sance tn the Manufacture of Kraft Paper (U. S. Public Health Service Reprint No. 2023, Public Health Reports, Vol. 54, Janu ary 13, 1939, p. 35). " Disposal of Refinery Wastes, Section II: Waste Gases, Va pors, Sludges and Dusts (American Petroleum Institute, 1938). n David Ronald: Offensive Trades (William Hodge and Co., London, 1935). "H. F. Coward and G. W. Jones: Limits of Inflammability of Gases and Vapors (U. S. Bureau of Mines Bulletin No. 379, 1939). "G. W. Jones: Inflammation limits and their practical ap plication in hazardous industrial operations (Chemical Reviews, Vol. 23, February 1938). "H. R. Brown: Private communication (U. S. Bureau of Mines). - "P. W. Edwards and L. R. Leinbach: Explosxbility of Ag ricultural and Other Dusts as Indicated by Maximum Pressure and Rates of Pressure Rise (II. S. Department of Agriculture Technical Bulletin No. 490, October 1935). ** H. R. Brown: Dust Explosion Hazards in Plants Produc ing or Handling Aluminum, Magnesium, or Zinc Powder (U. S. Bureau of Mines Information Circular No. 7148, March 1941). u I. Hartman, J. Nagy, and H. R. Brown: Inflammability and Bxplosibility of Metal Powders (U. S. Bureau of Mines Report of Investigation No. 3733, October 1943). "I. HAft-man and J- Nagy: Inflammability and Ezplosibihty of Powders Used in the Plastics Industry (U.S. Bureau of Mines Report of Investigation No. 3751, May 1944). ' **H. R. Brown: Industrial Dust Explosions (V. S. Bureau of Mines Information Circular No. 7309, January 1945). " Proposed Code for the Prevention of Dust Explosions in the Plastics Industry (National Fire Protection Asociation, May 1945). ** National Fire Codes for the Prevention of Dust Explosions (National Fire Protection Association, 1944). Contains codes for aluminum, magnesium, coal, pulverized .fuel, flour, spice, starch, sugar, cocoa, sulfur, and wood. . .. * G. Erdtman: An Introduction to Pollen Analysis (Chronica Botaiiica Co., Waltham, Massachusetts, 1943). . **R, P. Wodehouse: Pollen Grains (McGraw-Hill Book Co, New York, 1935). . . ` **R. P. Wodehouse: Atmospheric pollen (Aerobiology, Pub lication No. 17, 1943, p. 8). * R. P. Wodehouse: Hayfever Plants (Chronica Botanies Co, Waltham, Massachusetts, 1945).- - ** Hay Fever: A Geographical and Botanical Survey (E. R. Squibb and Sons, New York, 1937). 0 Techniques for appraising air-bome populations of micro organisms, pollen and insects (Phytopathology, Vol. 31, March 1941, p. 201). . ;. "B. J. Cody, W. F. Kinney, and N. A. Kerstein: Apparatus for Determining the Pollen Concentration of the Atmosphere (Research Department, Detroit Edison Company, Detroit). * 0. C. Durham: The volumetric incidence of atmospheric allergens (Journal of AUergy, Vol. 14, September 1943, p. 455). * o. C. Durham: The volumetric incidence of- atmospheric allergens, II: Simultaneous measurements by volumetric and gravity slide methods (Journal of Allergy, Vol. 15, May 1944, p. 226). . "O. C. Durham: Air-bome fungus spores as allergens (Aero biology, Publication No. 17, 1942, p. 32). "H. G. DuBuy and A. Hollaender: Sampling devices (Ameri can Journal of Medical Science, Vol. 209, February 1945, p. 172). "W. W. McIntosh: Ventilation Problems tn Safe Handling of Radioactive Materials (Paper presented at ASME Spring Meeting, March 1952). BIBLIOGRAPHY Monthly, annual, and special abstracts and bulletins (Indus trial Hygiene Foundation, Inc.). Aerobiology (Publication No. 17, 1942). W. N. Witheridge: Air sanitation and industrial ventilation (Detroit, Michigan, 1945). American Industrial Hygiene Association Quarterly. M. B. Jacobs: Analytical Chemistry of Industrial Poisons, Hazards and Solvents (Intererience Publishers, Inc., New York, 1941). . Bibliography of Industrial Hygiene, 1900-1943 (U. S. Public Health Service Bulletin No. 289, 1945). W. E. Gibbs: Clouds and Smokes (P. Blakiston's Son & Co., Philadelphia, 1924). Bloomfield and DallaValle: Determination and Control of Industrial Dust (U. S. Public Health Service Bulletin No. 217, 1935). S. C. Blacktin: Dust (The Sherwood Press, Cleveland, 1934). . The Environment and Its Effect upon Man (Harvard School of Public Health. Boston, 1937). Drinker and Hatch: Industrial Dust (McGraw-Hill Book Co., New York, 1936). A. D. Brandt: Industrial Health Engineering (John Wiley and Sons, New York, 1947). F. A. Patty (ed.): Industrial Hygiene and Toxicology (Inter science Publishers; Inc., New York, Vol. I, 1948 and Vol. H, 1$49). . Journal of Industrial Hygiene and Toxicology. See cumula tive abstract and subject indexes. . W. M. Gafafer et al: Manual of Industrial Hygiene (U. S. Public Health Service, W. B. Saunders Co., Philadelphia, 1943). Henderson and Haggard: Noxious Gases and the Principles of Respiration Influencing Their Action (American Chemical Society Monograph Series No. 35, Reinhold, New York, 1943). - Occupation and Health (International Labor Office, Wash ington, D.Cy 2 volumes). . . Lehmann and .Flury: Toxicology and Hygiene of Industrial Solvents (Translated by Eleanor King and H. F. Smyth, Jr, Williams & Wilkins, Baltimore, 1943). CHAPTER 8 AIR CONDITIONING IN THE PREVENTION AND TREATMENT OF DISEASE Sanitary Ventilation, Control of Airborne Infection, Value of Air Cooling Under Tropical Conditions, Treatment of Disease, Operating Rooms, Nurseries for Premature Infants, Fever Therapy, Cold Therapy, Allergic Disorders, Oxygen Therapy, General Hospital Air Conditioning ' HE Second World War caused an increase of interest individuals particularly were seriously affected'with cardio Tin the preventive aspects of air conditioning. It re-em respiratory symptoms. phasized the importance of the control of airborne infec The exact way in which the contaminants due to gaseous tion and demonstrated the value of air cooling under tropi wastes affect the human being is unknown* It is believed that cal conditions for the prevention of heat rash, for promoting the combination of contaminants rather than-any single proper rest and sleep, and in the convalescence of patients. substance produces the toxic effects. The medical profession The problem of air conditioning or air purification in has much to learn about the effects of contaminants on hu shelters, hospitals and other occupied buildings, to reduce man beings as a basis for determining when precise controls the hazard from radioactive particles following an atomic are needed.* explosion, merits the roost careful consideration. Shelters should be without windows, underground, strong enough to SANITARY VENTILATION resist blast and have sufficient cover to protect against ini tial radiation. They should be closed to outdoor air in the period immediately following & blast but may eventually have to be provided with ventilation from outdoors to limit the increase of temperature, moisture or odor, result ing from the occupancy, or in extreme cases to avoid seri ous oxygen deficiency and increase of carbon dioxide. When' air must be drawn from outdoors and power is available, a mechanical ventilation system can be used. This will make it possible to pressurize the shelter, to utilize special filtra tion apparatus and to control the entry of outdoor air at will. . A surface or subsurface burst of an atomic bomb will re sult in a wide dispersion of airborne radioactive particles.1 Windows of buildings within a three-mile radius from the point of detonation of a 20 KT bomb will be broken, and consequently, no appreciable protection will be afforded by the use of conventional air-conditioning systems under these conditions. Beyond the three-mile radius many structures may be found with windows undamaged and otherwise capa ble of providing some degree of protection from airborne radioactive particles by the utilization of an air-conditioning system. However, conventional air-conditioning systems During the last 20 years great popular interest has been aroused in the spread of respiratory infection indoors, and in its control by ventilation or its sanitary equivalent, air disinfection. In Europe three important documents have ap peared in English, Swedish, and French literature.4- * * In the United States where the study began, the vast literature has been consolidated, and definitions, formulations, and fac tors of sanitary ventilation codified in a volume now being edited for publication. .. The Council of Physical Medicine of the American Medical Association approved the radiant disinfection of air in 1943, and two sub-committees of the Committee on Research and Standards of the American Public Health Association have reported favorably upon the control of airborne infection by sanitary ventilation and on air sanitation respectively.1....... ... The ASHAE Technical Advisory Committee on Air Steriliza tion from 1944 to 1949 reported progress in The ASHAE Journal, and recommended a set of definitions, formula tions and factors for joint adoption by the American Public Health Association and the Society. The following section on Control of Airborne Infection gives some idea of the scope of the subject. ' should not be relied upon for protection in urban structures which may be utilized in the accomplishment of specific mis CONTROL OF AIRBORNE INFECTION sions following an atomic detonation. There are special The majority of airborne diseftfies are spread indoors techniques and devices available which will provide this where people gather. Any program of air sanitation is influ protection. enced by a number of factors. In the winter months, the The smog incident in Donora, Pa., in 1948 focused the at closing of doors, windows, and other means of access to the tention of health authorities and engineers on the problem outdoor air to conserve warmth, as well as the crowding of of air contamination by the gaseous wastes discharged into persons indoors, provides conditions conducive to a high the air above cities. The U. S. Public Health team investi incidence of contagion. This seasonal phenomenon, illus gating the incident* found that in this city several previous trated in Fig. 1 which represents a study made by. the U. S. incidences of lesser severity had occurred during the pre Public Health Service, will concern the ventilating engineer ceding 30 years as indicated by an increase of mortality insofar as air quality (determined by temperature, humidity, rates during certain periods. A high percentage of the popu air replenishment, type of air movement, and freedom from lation suffered to some extent during the 1948 smog. Older contamination) is a major intrinsic factor. Apart from the ' X 84 CHAPTER 8 1959 Guide spasnnftl picture of airborne contagion, are such extrinsic factors as rate of turnover of personnel, and the marked susceptibility of the recruit as compared with permanent personnel" as shown (see Fig. 2) by studies of military per sonnel boused in barracks. These extraneous variables and the factor of contact infection (direct spray) tend to com plicate any evaluation of the effectiveness of air sanitation for elimination of micro-organisms in droplet-nuclei and droplet-dust. Thus, control measures may eliminate con sistently 90 percent of airborne organisms in laboratory tests, but may not effect a decrease in actual incidence of infection exceeding 30 percent. Thirty percent may be the maxima] reduction in infection possible by air treatment methods. The distinction should be clearly drawn, therefore, between the effectiveness of a procedure in laboratory tests OccvrYanc* of diiRnH cawing disability for S eoasooatiro days or longer in o groop of 500,000 wag* comert (10 percent women) in differ ent industrial. Fig. 1.... Study of Averoge Monthly Frequency (1921-1926 Inclusive) of Specified Respiratory Diseases and its effectiveness and applicability in actually reducing the incidence of airborne disease. On the other hand, recent studies suggest that inhalation of dust-borne bacteria is more important than direct inhalation of infectious droplets or droplet nuclei in the spread of respiratory tract infec tions.1* *. . The following sequence of events has been postulated as occurring in a large proportion of intra-ward infections: (a) ejection of relatively large protected infective particles from patients; (6) rapid venting or settling of these particles so that those remaining airborne are in low concentration; (c) survival of infective particles to permit the accumulation of high concentrations on surfaces; (d) repeated reintroduc tion of infective particles into the air under the stimulus of ward activities or by air currents of the order of 60 fpm over the floor; and (e) extension of infective areas by air turbulence throughout the ward or hospital. The most im portant link in this probable infection chain has been demon strated to be the reintroduction of particles into the air." . Intensive studies on air disinfection have indicated two distinct control measures: (a) suppression of dust and lint, and (b) disinfection of droplet-nuclei. A third measure, con trol of relative humidity, is important. It has been shown that the viability of certain organisms sprayed into the atmosphere from a liquid suspension is dependent on rela tive humidity. The mortality rate of the organisms is very high at a relative humidity of 50 percent," and decreases at humidities above and below this figure. It has also been re ported that the influenza virus loses much of its virulence when the relative humidity is 50 percent.11 Well controlled, large scale tests of the various methods of air sterilization conducted in barracks**1" have con firmed the importance of dust control in minimizing the spread of airborne disease, a consideration which has guided the practices of ventilating engineers for a number of years. The importance of the dust factor has been emphasized by many engineers, and has been convincingly demonstrated by subsequent bacteriologic studies aboard ships. Treatment of floors and bedclothes with oil emulsions has proved effective in reducing bacterial dispersion by as much as 90 percent in Army barracks and station hospitals." The incidence of acute respiratory infections was from 10 to 30 percent lower in barracks with oiled floors and bedclothes than it was in control barracks which received no special treatment. More recent studies, however, have yielded in consistent results. An emulsifying mixture, Fimnol C containing cetyl pyridinium bromide, when incorporated in an oil-in-water emulsion imparted a bactericidal action. Blankets treated with this emulsion became bactericidal and retained this property for as long as three months. The possibility of hypersensitivity of an occasional individual to bromide drugs should be borne in mind when exposing large groups to treated gar ments or blankets." No simple method for disinfecting droplet-nuclei has yet been devised. Under favorable laboratory conditions, propyl ene glycol in concentrations of 0.07 to 0.14 milligrams per liter, and triethylene glycol in a concentration of 0.0045 milligrams per liter were highly germicidal for most air borne bacteria in clean air when the relative humidity was between 40 and 60 percent."1 " A humidity of 50 percent, without the use of glycol vapor, has been reported as de structive to some bacteria. However, maximum rates of bactericidal action of triethylene glycol vapor will be secured at humidities between 20 to 50 percent." In a recent report on the effect of triethylene glycol vapor in air disinfection, it is pointed out that the rate of ventila tion, as determined by the number of air changes per hour, is important and that continuous vaporization is needed to maintain effective concentrations of glycol vapor" In the absence of an apparatus to measure the concentration of vapor in the room, a slight fog is an indication of adequate concentration. Absence of such a fog indicates a non-bactericida! concentration. The report stated: "However, under experimental conditions we have observed no apparent de composition of triethylene glycol when temperatures up to 290 F were maintained at the rite of vaporization, provided the vaporizing unit was designed so that heat was applied to liquid glycol only at the point of vapor formation. On the other hand, decomposition was frequently observed when the vaporizing temperature was raised above 290 F, or when liquid glycol was kept above 120 F for long periods of time. The precise nature of the decomposition products is as yet unknown, but they may well be irritant or toxic and their formation should be avoided. For this reason, it is felt that a limit of 290 F should be applied to the tempera- Air Conditioning in Prevention and Treatment of Disease 85 tore employed in vaporization, and furthermore, that liquid glycol should not be heated above 120 F for long periods of time." It was also recommended that vaporizers be adjustable to a wide, range of output as measured by grams of liquid glycol vaporized per hour; for instance, from 06 g to at least 2.0 g per 1000 cu ft of volume treated, for small vapor izing units. Such high rates secure bactericidal concentra tion in less than an hour. Each room should be furnished with a single small vaporizer, and one vaporizer should not be expected to handle a volume greater than 4000 cu ft. Ap paratus for the production of glycol vapor, and an independ ent duct system for carrying this vapor and diluting air for large rooms or spaces, and unit type vaporizers for nrwall spaces, have been described" There is also available a de vice called the glycostat for the automatic regulation of glycol vapor in the air. This instrument has been calibrated to measure the degree of saturation of the air with glycol vapor by direct reading of the variations in the intensity of be applicable to present ultraviolet equipment installed in accordance with manufacturers' recommendations. The data, imply that air layers were not sufficiently mixed. However, more efficient mixing would have been obtained at the ex pense of increased circulation of dust and lint. Sources of ultraviolet radiation should be so situated as to protect the eyes of the occupants of the room from direct or reflected rays. A combination of ultraviolet radiation and dust con trol measures is believed to be more effective than either one of the two used alone, but the proof for this has yet to come. . .There is no doubt that these methods will reduce the number of bacteria in the air of an enclosed space, but there is still considerable question as to whether they are practi cal measures for reducing the total number of respiratory infections among personnel, since exposure by contact is an important factor. Bourdilion and his group concluded that there is justification for attempting to reduce the load -of airborne micro-organimis by the methods now available.* They have explored the properties of a number of com pounds, and their conclusions are in agreement with those of American investigators. The present status is admirably reviewed by the Commit tee on Sanitary Engineering of the National Research'Coun cil," and by a subcommittee of the American Public Health Association.* Both committees believe that the problem of air disinfection is still in the experimental stage. Since knowl edge of the effectiveness of glycol vapors has not kept pace with the development of vaporizing devices, there is real danger that commercial exploitation of the various devices may discredit the method and discourage careful research in - this important field " More experimentation is needed before a definite conclusion can be reached concerning its use in industry and public buildings. Fig.. 2.... Monthly Incidence of Acute Respiratory Illness... Among Naval Recruits and Ship's Company (Permanent' Personnel)1 VALUE OF AIR COOLING UNDER TROPICAL CONDITIONS light reflected from the glycol condensing surface of the wheel of the instrument." Under practical conditions, particularly in the presence of dust in the air, glycol effectiveness is much reduced. The use of other chemical aerosols that have been tried is limited by their toxicity,' odor, or destructiveness to fabrics and metals. A recently reported controlled "experiment in the offices of the Metropolitan Life Insurance Company showed that under ordinary working conditions triethylene glycol vapor failed to reduce the number of airborne bacteria and the in cidence rate of minor respiratory infections." - Ultraviolet radiation of floors and upper air has been studied extensively at the Naval Training Center, Sampson, N. Y. In barracks housing naval recruits, hospital admissions for respiratory infections (mostly catarrhal fever) were 25 percent lower in a group of men exposed to ultraviolet ra diation--2537 Angstrom Units, 1 to 7 ergs per (cm*) (sec) at bed level--than they were in adjacent control barracks without ultraviolet radiation." ' A controlled study over a six-:year period on the evalua tion of ultraviolet radiation of sleeping quarters as a supr piement to accepted methods of respiratory disease control has been reported." The amount of radiation over the last two years of the period was believed to be about five, times that recommended commercially. No significant effect on the incidence of disease could be detected in about 400 in mates during the six-year period. This conclusion may not Although statistics are not at hand to indicate the deaths or retarded recoveries of patients due to lack of air cooling in ships operating in tropical waters, it is generally agreed among- competent observers that high temperature and hu midity are major factors in prolonging disability and in creasing mortality of the sick and injured. Physiologic data obtained on healthy men, moreover, show the large loss of body fluids and the stress on the cardiovascular system in terms of increased pulse rate when these men are continu- ously subjected to high temperatures. Even at rest about 50 cc of fluid per hour are lost as sweat" through intact skin. In burn patients the difficulty, encountered in temperate climates, of maintaining fluid and electrolyte balance is tre mendously augmented by the additional evaporative fluid loss in hot environments. Naval hospital ships having all wards, laboratories, and living spaces air cooled, represent a notable achievement in the control of environmental fac tors for the purpose of providing better treatment of pa tients, especially those suffering from extensive bums. Patients who have such varied conditions as heart disease, thyrotoxicosis, shock from any cause, or severe hemorrhage, or those who have had an anesthetic, will invariably store heat when subjected to a hot humid environment. The gradi ent between the body surface temperature and the environ mental temperature is such that loss by radiation is slight. The heat loss by evaporation in a warm humid environment is low whether the patient does or does not perspire. Hie 86 CHAPTER 8 1959 Guide heat regulatory center may be temporarily deranged fol lowing an anesthetic, brain injury, or after an overdose of barbiturate. Loss of fluids and electrolytes is another influ encing factor. In these circumstances there is-great benefit from assisting the body in cooling, and this can best be done in a cool room of low relative humidity where conditions for heat loss are ideal. This measure is also valuable in con trolling temperature of patients, with various acute febrile diseases.- Frequently from 50 to 75 percent of personnel aboard naval vessels operating in tropical waters are afflicted with heat rash to a degree that interferes with rest and sleep. In carefully controlled experiments- it was possible to produce a fulminating type of rash in all men living continuously at an effective temperature of 85 (90 F dry-bulb'and 83 F wetbulb) . In the control group, 12 out of 24 hr were spent in- a relatively coo! atmosphere of 75 ET (80 F dry-bulb, and 70 F wet-bulb). These men either remained free from heat rash, or occasionally developed a mild form. Thus, inter mittent cooling to a degree that prevented swearing in.men at rest, eliminated a serious handicap to good performance of duty. In both laboratory tests and aboard hospital ships a rela tively cool living environment of 76 to 78 ET provided an atmosphere conducive to rest and sleep without excessive sweating- Berthing spaces tended to have extremely low odor levels. Motivation, initiative and alertness, in contrast to the usual irritability and lack of incentive incident to resi dence in tropical climate, were maintained.-' ' Little has been done, however, to obtain practical methods for application of air conditioning under heavy heat loads and on the enormous scale that would be needed to modify life in the tropics. Part rime coding of personnel to pro mote rest and sleep in tropical areas would provide a pro phylactic measure of great potential importance. TREATMENT OF DISEASE In the past few years considerable progress has been made in using air conditioning as an adjunct in the treatment of various diseases. Among the important applications are those in operating rooms, nurseries for premature infants, mater nity and delivery rooms, children's wards, clinics for arth ritic patients, heat therapy, cold therapy, oxygen therapy, X-ray rooms, and the control of allergic disorders. Normal individuals may be subjected to considerable strain in adjusting to hot humid conditions. Heat loss by ra diation is reduced, as is loss by evaporation of sweat. Indi viduals with certain disease processes are at a still greater disadvantage since they may also have difficulty in the trans port of heat from the interior to the surface of the body via the circulation. Patients with thyrotoxicosis tolerate hot humid conditions or heat waves very poorly. Their metabolism is high, and therefore their heat production is excessive. They may be unable to eliminate heat from the body surface as rapidly as it is produced and transported to the skin. They develop hyperthermia or fever, and a tachycardia or rapid heart rate. The demand on the circulation for transport of heat from the interior of the body to the skin surface is increased. The increased body temperature leads to increased cell metabolism, and in turn to still greater heat production. This vicious cycle may threaten life if the cardio-vascular or transport mechanism breaks down. A cool, dry environment favors the loss of heat by radiation and evaporation from the skin, and may save the life of the patient. Cardiac patients may be unable to maintain the circula tion necessary to insure normal heat loss. Recently the im portance of air conditioning hospital wards and rooms of cardiac patients, particularly those with congestive heart failure, has been stressed as a therapeutic measure.- It is more important in tropical or subtropical climates. Indi viduals with head injuries, those subjected to brain opera tions, and those with barbiturate poisoning may have hy perthermia, especially in a hot environment, due- to a disturbance in the heat regulatory center of the brain. Ob viously, one of the most important factors in recovery is an environment in which' the patient can lose heat by radiation and evaporation, namely, a cool room with dehumidified air. The patient in shock, or the patient who has had a severe hemorrhage, may have an inadequate volume of circulating blood and be unable to maintain an adequate skin circula tion. This may result in heat storage or fever. Patients with extensive skin bums may be unable to lose heat adequately from the limited uninvolved skin surface, and thus develop a fever. They need adequate fluid replacement, saline solu tion, plasma or blood to expand the circulating blood volume and thereby improve peripheral circulation. A cool environ ment is valuable in aiding heat loss after adequate skin circulation is established. ' A hot dry environment (89.6 F and 35 percent relative hu midity) has been used over an extended period for the treatment of patients with rheumatoid arthritis, with re ported improvement.- OPERATING ROOMS The widest application of air conditioning in hospitals is in operating rooms. Complete air conditioning of operating, wards is important because winter humidification helps re duce the danger incident to the use of anesthetic gases; summer cooling with some dehumidification tends to elimi nate excessive fatigue and to protect the patient and oper ating personnel; and finally, filtering aids the removal of allergens from the operating room air. . Reducing Explosion Hazard Explosion hazards in operating rooms increase with the introduction of anesthetic gases and apparatus. Ether ad ministered by the old drop method gives rise to an ex plosive mixture, but in practice this method is still regarded as comparatively safe. When ether is mixed with pure oxy gen, or nitrous oxide in certain concentrations, the explo sion hazard may be as great as with ethylene-oxygen, or cy clopropane-oxygen mixtures. Of the anesthetic gases nitrous oxide alone does not ex plode but supports combustion. Ether, vinyl ether, ethylene, and cyclopropane are as potentially dangerous as gasoline or illuminating gas in the home.- Chloroform does not ex plode violently in contact with flame, but decomposes to liberate phosgene. All of the anesthetic gases and vapors, except ethylene, are heavier than air. Although the incidence of injury or death from explosion is negligible compared with other hazards in the operating room, the dramatic features surrounding an explosion justify continued investigation to eliminate the hazard. . During the course of ethylene anesthesia, the mixture, usually 80 percent ethylene and 20 percent oxygen, is so rich that the danger of explosion is slight in the immediate vicinity of the face mask, but leakage of ethylene into the Air Conditioning in Prevention and Treatment of Disease 87 air may result in lower concentrations, and thus introduce a serious hazard. The most dangerous period is at the end of the operation when the patient's lungs and the anesthesia apparatus are customarily washed out with oxygen with or without the addition of carbon dioxide. Even when this procedure is omitted, it is difficult in practice to avoid dilu tion of the anesthetic gas with air during the normal course of breathing following the administration. In either case the mixture would pass through the explosion range and extraordinary precaution is necessary for the safety of the patient and operating personnel. . In a study- of 230 anesthetic explosions and fires, 70 per cent of the explosions and 60 percent of the deaths were caused by igniting agents other than static sparks. The Na tional Fire Protection Association- made certain recom mendations for safe practice based on available information in Pamphlet No. 56, Recommended Safe Practice for Hos pital Operating Rooms (July 1952). These recommenda tions outline ways and means for eliminating or correcting hazardous conditions which experience and investigation have shown to contribute to the hazards in question. They are divided into three parts: Part I, General, deals with the nature of. the hazards, Part II, Construction and Equipment, deals with physical standards for features incorporated into the construction and equipment of the surgical suite, and Part III, Administration, contains precautions to be ob served by hospital personnel. The requirements and recom mendations are interdependent and each will be ineffective unless coordinated with the other. To approach complete success in the prevention of anesthetic explosions, all per sons--the surgical staff, the nursing staff, the maintenance staff and administrative personnel--must be educated and periodically reminded of the explosive nature of combusti ble anesthetic agents. Experience has shown that neither high humidity nor in tercoupling devices have eliminated the danger from static... electric discharge. The removal of gas concentrations from the operating table area, by means of specially devised ex haust ventilation, should be thoroughly tested. Portable duct systems as installed aboard ship should be acceptable. Seri ous explosions can occur in a closed system, but proper pre cautions will reduce this hazard to a minimum. A comprehensive study of the explosion problem and of the general causes and prevention of operating room hazards, by the University of Pittsburgh, the ASHAE Research Lab oratory, and the U. S. Bureau of Mines has led to a fruitful attempt to eliminate the explosive range of cyclopropane* one of the best but most difficult gases to handle. The use of helium as a diluent in the total gaseous mixture controls the oxygen concentration by displacement and, because of its flame quenching properties, it is the ideal gas for this purpose. In addition, a gaseous mixture containing helium is more .difficult to ignite by electric discharges, and this qual ity also increases the safety factor of anesthetic administra tion. . Operating Room Conditions - Little is known about optimum air conditions for main taining normal body temperatures during anesthesia and the immediate post-operative period. An anesthetized patient displays dilation of blood' vessels in the skin resulting in profuse sweating and (it has been believed) inability to regu late body temperature. From this it was concluded that all anesthetized patients suffered considerable heat loss, al though there may be little more than 0.8 F deg variation in the rectal temperature during the course of the operation." The severe physiological effects, such as excessive sweating and rapid pulse, of high operating room temperatures on attendants and patients during the hot months signify the need for proper cooling. Statements of surgeons who operate in both air-conditioned and non-air-conditioned rooms strongly indicate that the recuperative power of the patient is greater when operated upon in air-conditioned rooms." Although the comfortable air conditions for the operators are not identical with those for the patient, it is usually not difficult to compromise within a range of 55 to 60 per cent relative humidity and 72 to 80 F temperature. It is gen erally reported that dry-bulb temperatures of 76 to 78 F with 55 percent relative humidity not only furnished com fort for the operating room workers, but apparently pre vented exhaustion of patients as evidenced by rapid con valescence in the recovery ward. Additional heat may be furnished to patients locally or by suitable covering, ac cording to body temperature in individual cases. In the control of airborne infection in the operating room, the prevention of dispersal of infectious materials into the air, control of dust, and proper ventilation supersede at tempts to remove or kill pathogenic organisms. The bac terial content of conditioned operating rooms is generally lower than that of Don-conditioned rooms. Bacterial counts aboard an air-conditioned submarine were found to be exceptionally low and not cumulative with time, although all of the air was recirculated for more than 12 hours" without replenishment. The removal of bacteria by the process of air cooling and condensation of moisture out of air, merits further study.- The degree of air contamination can be reduced by proper ventilation if velocity of air over the floor does not exceed 50 fpm. Research is in progress on the use of filtered air Sowing through a system of mechanical cleaners which pro tect the patient against infection from attendants, and from bacteria-containing air in the corridor or ward " Operations are frequently postponed on allergic patients during asthmatic manifestations through fear of complica tions. The removal of airborne allergens, therefore, is in some cases an important function of the air-conditioning sys tem in preparing patients for operation. The best practice in air conditioning hospital operating rooms is the use of all outdoor air with arrangements for preheat, reheat, and the control of humidity, coupled with a mechanical exhaust system that removes the air from both the high and low levels of the operating room.. However, there is some evidence of lack of any cumulative effect on bacteria count due to recirculation of air through an air conditioning unit in operating rooms. This consideration and the fact that relief cooling frequently provides improved, if not ideal conditions, has led to the use of central systems employing 50 percent recirculated, air. Also, perhaps as a recognition of practice, the NBFU Pamphlet No. 56 outlines the conditions under which room air conditioners may be used in operating rooms. These conditions are so written in the pamphlet that the recommendation of separate me chanical ventilation of such rooms is clearly inferred. ' Stated in the reverse order, room air conditioners for re lief cooling of mechanically ventilated rooms are now con sidered permissible when used with the necessary precau tions. These precautions are not generally assured by the use of standard room air conditioners as produced by the manufacturers, and are frequently costly of accomplishment in the field. The use of larger systems employing 50 percent S 88 CHAPTER 8 1959 Guide recirculated air is a recognized practice. It is certain that such a system must have the necessary precautions (re garding the electrical and air moving equipment) against the hazard of gross spillage of the anesthetics. Systems using 100 percent outdoor air and adequate air removal means are regarded as following the best practice. The choice between the systems is-usually made on the basis of first costs. As compared with the other daily usage costs of an operating room, the differences between the operating costs of the various air conditioning systems is not a significant item. Good thermal construction of the operating rooms is a recommended practice. Much can be gained by thermal in sulation of sterilizing equipment, and by exhaust ventilation of sterilizing rooms adjoining the operating rooms. The amount of glass surface should be kept to a minimum, par ticularly in walls exposed to the sun. Double windows are desirable and often necessary to prevent condensation on the glass in cold weather. The equipment capacity and con trol methods must be properly selected for the type of sys tem employed, and for the loads encountered. The result ing air flow rates are usually in the range of 8 to 12 changes per hour. The method of air introduction should be selected to keep air movement in the operating area under 50 fpm. Where all outdoor air or a large percentage of outdoor air is used, the air introduction and exhaust arrangements should be designed to provide a thorough air change in all parts of the room. This may be accomplished by introducing the air at one side and exhausting it from the other side of a small room or by introducing the air at the center and exhausting from the sides of a large room. The supply and exhaust arrangements can be exchanged in the case of large rooms. An air-conditioned recovery ward in connection with the air-conditioned operating room, is of great value in stabiliz ing peripheral circulation, and in reducing excessive loss of fluids on hot humid days. NURSERIES FOR PREMATURE INFANTS One.of the most important requirements in the care of premature infants is the stabilization of body temperature. This is necessary because the infant's heat regulatory sys tem is not fully developed, with the resultant tendency for environmental temperature to influence body temperature. The younger the premature infant, the greater is the tend ency. As the infant's metabolism is low, heat production is not: adequate to maintain a normal body temperature in a cool environment. The resistance to infection is low, and - the mortality rate is high. In general, the younger the age of the premature infant, the higher the mortality rate. ' Nurseries constructed for metabolic research should be air- conditioned so that conditions are reproducible. Results of such studies may be invalid if environmental conditions are not identical, since fluid and electrolyte loss may vary greatly with change in environmental conditions. Air-Conditioning Requirements The optimum air conditions for growth and development of premature infants were determined by extensive research" at the Children's Hospital, Boston, Mass., using four, valid criteria, namely, stability of body temperature, gain in weight, incidence of digestive syndromes, and mortality. In dividual temperature requirements varied widely (from 72 to 100 F) according to the constitutional state of the infants and body weights. The optimum relative humidity was about 65 percent, and the air movement less than 20 fpm. A single nursery conditioned to 77 F and 65 percent rela tive humidity was found to fulfill satisfactorily the require ments of the majority of premature infants. Additional heat for weak (or debilitated} infsuite may be furnished in luc cribs or by means of electric incubators placed inside the conditioned nursery, with temperature adjusted according to individual requirements. In this way a multiplicity of chambers and of air-conditioning apparatus is obviated; the infants in the heated beds derive the benefit of breathing cool humid air, and the nurses and doctors need not expose themselves to extreme conditions. Importance of Httmidity: Although external heat is an important factor in the maintenance of normal body tem perature, humidity appears to be of equal or greater impor tance. When the premature nurseries at the Children's Hos pital were kept- at relative humidity between 25 and 50 percent for two weeks or longer, the body temperature be came unstable, gain in weight diminished, the incidence of gastro-intestinal disturbances increased, and the mortality rose. On the other hand, continuous exposure to air condi tions with 55 to 65 percent relative humidity gave satis factory results over a period of years. The initial physiologic loss of body weight (loss occurring within first four days of life) was found to vary inversely with the humidity. In the old nurseries with natural humidity it averaged 12.4 percent of the birth weight; in the conditioned nurseries it was 8.9 percent with 25 to 49 percent relative humidity, and 6.0 percent; with 50 to 75 percent relative humidity. The number of days required to regain the birth weight was correspondingly maximum in the old nursery, and minimum in the conditioned nurseries under high humidity. Maximum gains in body -weight occurred in the condi tioned nurseries under high humidity (55 to 65 percent) in infants weighing less than 5 lb. The gains were less under low humidity (25 to 50 percent) in the same nurseries, and in the old nurseries prior to use of air-conditioning apparatus. The incidence and severity of digestive syndromes, with diarrhea, persistent vomiting, diminishing gain or loss of bbdy weight, and other symptoms, were generally from two to three times as high under low as under high humidity. Summarizing, the best chances for life in premature in fants are created by maintaining a relative humidity of 65 percent in the nursery, and by providing a uniform environ mental temperature just sufficiently high to keep the body temperature within normal limits. Medical and nursing care are, of course, factors of equal and sometimes of greater im- - portance. ... Air-Conditioning Equipment Many of the installations now in use are of the central system type providing for filtration, for humidification and heating in cold weather, and, for cooling and dehumidifica tion in hot weather. A ventilation rate between 8 and 12 air changes per hour is desirable to remove odors and maintain uniformity of temperatures in extremes of weather. Re circulation should not be used in these wards owing to odors and the possibility of infection. There should be a frequent change in spray water. Control of Airborne Infection The protection of the premature and older infant against infection is of the utmost importance. It was found in one installation equipped with air conditioning, germicidal lights and mechanical barriers that air. conditioning alone did not Air Conditioning in Prevention and Treatment of Disease 89 prevent respiratory cross-infections" Bacterial ultraviolet barriers, air conditioning and mechanical barriers are effi cient; However, infections are brought in by, and often spread by, ward personnel in spite of these measures. . FEVER THERAPY Artificial production of high fever in man can be con sidered an imitation of nature's way of overcoming invading pathogenic organisms. The action may be direct and specific by destruction of the invading organism within the safe limit of human temperatures, or indirect in the case of heat resistant organisms, by general mobilization of the defensive mechanisms of the body. Although the action may be direct and specific by destruc tion of the invading organisms within the safe human limits, fever therapy exerts much of its benefit through the im provement of -the mechanism of bodily defense. A serious challenge to the theory on which fever therapy is based comes from the demonstration that high fever causes a re duction in the concentration of circulating antibodies in ex perimental animals. Patients for fever therapy should be carefully selected. The most serious complications which may arise, are heat stroke, heat exhaustion and circulatory collapse. The chief . minor complications are heat cramps, fever blisters and mild dehydration. The limits of induced systemic fever are usually between 104 and 107 F (rectal), and the duration from 3 to 8 hours at a time. The total period of fever treatment varies with the type of the organism involved. The diseases which respond favorably to artificial fever therapy are gonorrhea and its complications (which include arthritis, pelvic infections in women, and involvement of the eye), syphilis and chorea. The most striking results are seen in gonorrhea and syph ilis, since the causative organisms can be destroyed at tem; peratures compatible with human life. However, the use of fever therapy has decreased since penicillin has been found so effective in the treatment of gonorrhea and syphilis. Mild fever, up to 101 F for one hour, has revently been used in the treatment of rheumatoid arthritis. This degree of fever is not bactericidal, but is believed to stimulate the body defense mechanism. Equipment for Production of-.-Fever Artificial fever can be induced by injections of various crystalloid or colloid substances, bacterial products of ty phoid and malarial organisms, or by physical methods using hot baths, radiant heat cabinets, hot humidified air cabinets, or by short wave diathermy in combination with a cabinet. The relative advantages of various methods have been evaluated clinically.** Among the devices for the production of fever by physical means, the one most widely used is the hot humid air or air-conditioned cabinet. This apparatus was developed at the Kettering Institute for Medical Re search at Miami Valley Hospital in Dayton, Ohio. In the - earlier studies of the Society, temperatures were elevated more easily using saturated atmospheres; A fever therapy apparatus*4 using,these same principles has proved efficient .as a means of inducing and maintaining fever in a body,, with small likelihood of burns because of the com paratively low dry-bulb temperatures. When heat is necessary in treating legs or arms, such media as short- or long-wave diathermy, micro-waves, infra red, water baths, etc., have been used extensively. A recent development, a saturated atmosphere heating unit, similar to one previously described has proven satisfactory, because heat may be administered over longer periods which render deep heating possible without fear of burns or shocks. Local heating has been somewhat satisfactory in relieving the painful symptoms of peripheral vascular disease. This pro cedure, however, is not without danger. Elevation of tissue temperature increases cell metabolism and the need for oxygen. The inadequate blood supply and oxygen deficiency may lead to tissue death or gangrene. Application of heat to the trunk or'abdomen, with consequent reflex dilatation of the vessels of the extremities, eliminates this Hunger of local heat application. - Short-wave diathermy within the cabinet during the in duction phase has been used. When the desired body tem perature has been reached by electrical induction, the at mosphere of the enclosure is kept at saturation to prevent heat loss, thus maintaining the patient's temperature at the desired point. The two underlying principles in the pro duction of fever by the hot humid air cabinet are: (1) the transfer of heat by conduction from the circulating hot air to .the body, and (2) prevention of heat loss. The latter is more important. In an atmosphere of high humidity, the heat loss by evaporation is markedly decreased. COLD THERAPY Cold as an anesthetic agent was advocated by Allen several years ago* Freezing of the tissue must be avoided. For cer tain patients, in whom amputation of an extremity is indi cated, the application of a tourniquet with cooling of the affected extremity down to near freezing (5 C or 40 F) is of .value. The patient, following this procedure can be pre?pared for surgery without the handicap of absorption of septic products and severe pain. This procedure has proven . especially valuable in the neglected diabetic patient with an infected gangrenous extremity. Time for treatment of coma and hydration of the patient is gained. However, if amputa tion of an extremity is not indicated, the application of a tourniquet and packing in ice are dangerous procedures, since loss of the limb usually results. An extremity with inadequate blood supply can be readily cooled without the use of a tourniquet, but such an extremity is also usually eventually lost. Cooling is said to reduce the metabolism of the tissue with suspension of the vital processes. It also reduces the blood flow to practically zero, and few ex tremities with inadequate blood supply remain viable or recover. Packing in ice, or use of low temperatures, is contra indicated in the treatment of patients with frostbite, im mersion foot or trench foot. The affected extremities should . be exposed to the air in & cool room and not rubbed with snow or packed in ice. The lowering of temperature by packing the body in ice for treatment of cancer has not proven successful. The methods used for refrigeration, depending upon avail able facilities, are as follows:** (1) Cracked or shaved ice which is simple and has the ad vantage of not freezing tissues. However, it is cumbersome and sloppy to handle and is unsuited to prolonged treatments. (2) Use of ice in a pail for immersion of local parts. - (3) Special boxes for holding ice with padded or curtained openings for the limb. - (4) Bare ice bags and cloth bags for iced wet dressings for prolonged treatments and convenience. ' 90 CHAPTER 8 1959 Guide (5) A double-chambered cabinet using dry ice has been constructed. (6) Electrical refrigerating apparatus, consisting of a com pact noiseless unit that pumps fluid to various types of ap plications, is available. The applicators may be in the form of blankets containing rubber tubes suitable for covering the entire body, or all or part of a limb. Special applicators are available for insertion into various body cavities, and for in ducing dental anesthesia. (7) An air chamber at regulated temperature for treatments of frostbite and immersion foot, and amputation stumps. The electrical apparatus is costly, but has the advantages of thermostatic regulation, light weight, freedom of move ment, and permits prolonged treatments with heat, as well as cold over the range of temperatures therapeutically desirable. ALLERGIC DISORDERS Hay fever, asthma, Arr-pma and contact dermatitis are rlajsafiftfi as allergic disorders. The allergic individual re sponds to contact with a variety of substances, which are innocuous to a non-allergic person, with severe manifesta tions of hypersensitivity. These substances are known as allergens and consist of airborne irritants such as dusts, molds, feathers, pollens, animal dander and others; of food protein such as milk, wheat, eggs, etc., or of simple chemicals brought in contact with the skin. They may enter the body by various routes of which inhalation is the most common type. Ingestion of offending food substances is not infrequent. The offending substance reacts with the sensitized cells of the mucous membranes or skin. During this reaction, hiataifiina or a histAmina-like substance is released and causes (a) increased capillary permeability, (b) secretion of mucus and (c) muscular contraction. In the eyes and nose this produces itching, redness and lacrimation or rhinorrhea, in short, the symptoms of hay fever. In the lungs it causes, in addition to the secretory response, a contraction of the smooth muscles of the bronchi resulting in a bronchial asthma. It is commonly known that non-specific environmental factors such as dust, irritating gases, change of temperature and humidity may precipitate asthmatic attacks in allergic subjects, even in the absence of exposure to specific allergens. It is assumed that the presence of frequent allergic bronchial constriction renders the smooth muscles of the bronchi so sensitive to various non-specific stimuli that the threshold of their response to such irritation is considerably lower than that of a non-allergic individual. A/r-Condirioning Apparatus Of all the measures to relieve a specifically sensitive in dividual, elimination of exposure to the responsible allergen is the most efficient, though not always a practical, form of treatment. In recent years considerable effort has been made to accomplish such elimination by removal of respiratory allergens from enclosures by filtration or other air-condition ing processes. . Paper or cloth filters, mounted in inexpensive window or floor units, prove quite satisfactory in many cases, but since dust and smoke frequently cause asthmatic attacks, it is desirable that an air filter, to be of full value in the treat ment of asthma, should remove all posable dusts and pollens regardless of size or amount. Electrostatic air cleaners are more efficient than most commonly used types for. capturing very fine dust. Although the chief remedial factor in the treatment by conditioned air is the filtration of pollen, a certain amount of cooling and dehumidification appears to be desirable. A comfortable temperature between 70 and 75 F, and a rela tive humidity well below 50 percent has proved satisfactory.*' Direct drafts, overcooling or overheating are apt to initiate or aggravate the symptoms. Limitations of Air-Conditioning Methods The results obtained with air filtration, or other air con ditioning processes, in the control of allergic conditions, are fairly comparable to those obtained by desensitization treat ment, so long as the patients remain in the pollen-free at mosphere. For all practical purposes filtration gives only temporary relief. In mild cases sleeping in an air-conditioned space may make it possible for the individual to pass more comfortable nights. With rare exceptions, the symptoms recur on exposure to pollen-laden air. Moreover, the useful ness of air-conditioning methods is limited, because all cases are not caused by airborne substances. Cases of bacterial asthma do not respond to treatment with filtered air. Despite these limitations, air-conditioning methods possess definite advantages in the simplicity of treatment, con venience, and under certain conditions, almost immediate relief." Pollen cases are usually relieved of most of their symptoms within 1 to 3 hr after exposure to properly filtered air. A pollen-free atmosphere is especially valuable when desensitization has given little or no relief, and when desensitization is not advisable owing to intercurrent illness. OXYGEN THERAPY Oxygen therapy is used to prevent or relieve anoxia. Some of the more important clinical conditions in which oxygen treatment is beneficial include pneumonia, severe anemia, cardiac decompensation, pulmonary atelectasis, asphyxia and *asthma The effectiveness of oxygen therapy is dependent on the concentration of the oxygen in the inspired air, or the partial pressure of oxygen in the pulmonary alveoli. Oxygen is usually administered by nasal catheter, face mask or tent.- The necessity of air conditioning in oxygen . therapy arises from the fact that oxygen is too expensive a gas to waste in the ventilation of oxygen tents and oxygen chambers. Air conditioning is applied to the oxygen tent or chamber through reconditioning of the atmosphere in a closed circuit. Excessive heat, moisture and carbon dioxide are removed. , Oxygen Tents In oxygen tents, the air enriched with oxygen is usually circulated by means of a small motor blower which sends the air over soda lime to remove carbon dioxide, and then over ice to remove excess heat and moisture. The concentration of oxygen in the tent is regulated by means of a pressure reducing valve and flow meter. In an inadequately cooled tent, high temperatures and humidities are inevitable, in creasing the discomfort of the patient and imposing an added strain on an already overburdened heart. Oxygen therapy under such conditions may do more harm than good. An ice melting rate of approximately 10 lb per hr gives satisfactory results in patients with fever in a medium size oxygen tent. Oxygen tents are confining to the patient. They may terrify the restless and delirious patient. Medical and nursing Aif .Conditioning in Prevention and Treatment of Disease 91 care is complicated, as the tent must be opened or removed with attendant loss of oxygen. Oxygen concentrations of 50 percent or more are difficult to maintain, and it is a problem to keep the. temperature and humidity low enough in hot weather.-However, with attention to details, the patient can be:>made quite comfortable. In fact, during hot humid weather an oxygen tent may be very valuable in controlling a patient's temperature, since the upper part of the body within the cooled tent loses heat rapidly. . Oxygen Chambers The conventional oxygen chamber is an air-tight sheet- metal enclosure of fire-proof construction, large enough to accommodate one or two patients. Trap doors or curtains are provided for the personnel, food and service, to avoid loss of oxygen. Glass windows in the ceiling and walls admit light from outside the chamber. The air conditioning system may be of the gravity, type, or of the fan type using me chanical refrigeration or air drying agents. The temperature and humidity requirement. in oxygen therapy depends-primarily upon the physical condition of the patient, and secondarily upon the type of disease. In pneumonias- prescribed conditions should be a temperature of 'GO to 75 F, humidity 50 to 55 percent, moderate air movement, oxygen concentration of 50 percent, and carbon dioxide of less than one percent. . Oxygen in Aviation An important application of the principle of oxygen ther apy is in aviation: High altitude military airplanes in thw country are normally provided with gaseous oxygen equip ment, and military personnel are required to utilize oxygen at all times while in flight above 15,000 ft, or between 12,000 to 15,000 ft for longer than two hours, or between 10,000 to 12,000 ft for longer than six hours. Today all large passenger aircraft are pressurized to pro vide passenger comfort in flight at altitudes of 20,000 feet or more. Smaller civilian aircraft are usually not pressurized and must carry gaseous oxygen equipment where appreciable altitudes must be attained. the South, it can be used to advantage from May to October, and in tropical climates almost continuously throughout the year. F. "L. Grocott of the Anglo-Iranian Oil Co. states that in Iran, the medical staff after 10 years' experience with air conditioning, demand a ^uniform environment of 75 F and 50 percent relative humidity under all summer outdoor conditions for general wards and treatment rooms, and 70 F with 30 to 50 percent relative humidity for winter condi tions. In the operating rooms, 70 F with 50 percent relative humidity is demanded all the year 'round, although the annual external range is 40 F to 120 F. No ill effects have been noted in the medical personnel, though they are ex posed to changes from external to internal conditions many times daily. Temperature shock in either direction seems to create discomfort for a short interval, but if the individual is in good health, no injury results.- ` Aside from comfort and recuperative power of the pa tients, cooling is of great assistance in the treatment of fevers in the new-born and in post-operative cases, in enteric disorders, fevers, heat stroke, heart failure, thyroid crisis, and in a variety of other ailments which often ac company summer heat waves. Problem of Odors Experiences in the evacuation of battle casualties in air craft and their subsequent hospitalization have stimulated efforts to find ways of minimizing odors arising from drain ring wounds, old odorous casts, and gangrenous wounds. For aircraft, chemical sprays and vapors, perfumes, oxidizing gases and simple exhaust methods are unsatisfactory. An ideal deodorant would purify the air by means of odor adsorption so that subsequently the air could be recirculated. Based upon the effectiveness of activated carbon commer.. cially and industrially to adsorb odors, individual adsorp tion units have been used successfully. In hospital wards the feasibility of adsorption methods over other methods for elimination of odors remains to be answered.- REFERENCES GENERAL HOSPITAL AIR CONDITIONING Complete conditioning of a large hospital involves a capital investment and running-expenses which may not be justified. In clean and quiet districts, the requirements of almost all general and private wards during the cool season of the year can be satisfactorily fulfilled by the use of con ventional heating equipment, in conjunction with window air supply and gravity or mechanical exhaust. Insulation against heat and sound is much more important than humidi fication in winter; thermal insulation will also help in keep ing the building cool in warm weather. Excessive outside noise and dust may require the use of silencers and air filters in the openings. Cooling and dehumidification in warm weather are im portant. In new hospitals particularly, the desirability of cooling certain sections of the building should be given seri ous consideration. Financial reasons may preclude the cool ing of the entire building, but the needs of the average hospital can be met by the use of built-in room coolers and a few portable units which can be wheeled from ward to ward when needed. In the North, and certain sections of the Pacific Coast, cooling is needed but a few days during summer, while in 1 The Effects of Atomic Weapons (U. S. Government Print ing Office, revised September 1950). SJ. G. Townsend, MX).: Investigation of the smog incident in Donora, Pa., and vicinity (American Journal of Public Health 40: 183, February 1950). *C. P. McCord, MU.: The phvsiologic aspects of atmos pheric pollution (Industrial Medicine and Surgery 19-97 March 1950). * R. B. Bourdilion, O. M. Lidwell, and J. E. Lovelock with W. C. Cawston, L. Colebrook, F. P. Ellis, M. V. Ende, R. E. Glover, A. M. Macfarlan, A. A. Miles, W. F. Raymond, E. Schuster, and J. C. Thomas: Studies in Air Hygiene (Medical Research Council of Great Britain, 1948, Special Report Series No. 262). . *H. E. Rouge: Ultraviolet Irradiation with Artificial Il lumination (Uppsala, Sweden, 1948). *P. A. Burrucand; L'Hygiene du Bailment per L'Ultra- violet (Centre Scientific et Technique du Batiment, Paris 1949). ' 'Council of Physical Therapy: Acceptance of ultraviolet lamps for disinfecting purposes (Journal of American Medical Association 122 : 503, 1943). . *J- E. Perkins: Evaluation of methods to control airborne infection (American Journal of Public Health 35:891, 1945). 'Committee on Evaluation of Methods to Control Airborne Infections of the American Public Health Association: The present status of the control of airborne infections (American Public Health Association Journal 37:13, 1947). 92 CHAPTER 8 1959 Guide *Subcommittee on Air Sanitation: Progress in the control of airborne, infections (American Public Health Association Yearbook 40:5, May 1950, p. 82). "S. M. Wheeler and T. D. Jones: Factors in the control of the spread of acute respiratory infections with reference to streptococcal illness ana acute rheumatic fever (American Journal of the Medical Sciences 209:58, 1945). "CrG. Loosli: Dust control, report on suppressive measures for the control of dust to the Standards Methods Committee for. the Examination of Germicides and Antibacterial Agents (American Journal of Public Health, March 1948, p. 409). " A. P. Krueger et al: Laboratory and field studies of gly cols and floor-oiling in the control of air-borne bacteria (U. S. Naval Medical Bulletin 42:1288, 1944). u E. W. Dunklin and T. T. Puck: The lethal effect of rela tive humidity on air-borne bacteria (Journal of Experimental Medicine 87:87, February 1948). "Quotation by William Lester, Jr. in Health on the Job No. 22 (Institute of Industrial Medicine, New York Univer sity, February 1949). ' "H. M. Lemon, H. Wise, and M. Hamburger: Bacterial content of air in army barracks (War Medicine 6:92, 1944). - ffO. H. Robertson, M. Hamburger, C. G. Loosli, T. T. Puck, and H. M. Lemon: A study of the nature and control of air borne infection in army camps (Journal of the American Medi cal Association 126:993, 1944). . "O. H. Robertson et al: Lethal effects of triethylene glycol vapor on air-borne bacteria and influenza virus (Science 97: 142, 1943). "M. Hamburger, Jr., O. H. Robertson, and T. T. Puck: The present status of glycol vapors in air sterilization (American Journal of the Medical Sciences 209:162, 1945). "T. N. Harris and J. Stokes, Jr.: Summapr of a 3-year study of the tilinical applications of the disinfection of air by glycol vapors (American Journal of the Medical Sciences 209:152, 1945). . " William Lester, Jr., Saul Kaye, 0. H. Robertson, and Ed ward Dunklin: Factors of importance in the use of triethylcne glycol vapor for aerial disinfection (American Journal of Pub lic Health 40:813, July 1, 1950). "Edward Bigg, B. H. Jennings, and F. C. W. Olson: Tn- ethylene glycol vapor distribution for air sterilization (ASHVE Transactions, Vol. 53, 1947, p. 393). "Glycol vapors for disinfecting purposes (Journal of the American Medical Association 133:696, March 8, 1947). ** W. J. McConnell: An experiment with Lriethylene glycol vapor for the control of colds among office employees (In dustrial Medidne 18:5, page 192). "S. M. Wheeler, H. S- Ingraham, A. Hollaender, N. D. Lili, J. Gershon-Cohen, and E. W. Brown: Ultra-violet light con trol of airborne infections in a naval training center (American Journal of Public Health, Vol. 35,1945, p. 457). "H. G. DuBuy, J. E. Dun, F. S. Brackett, W. C. Dressen, P. A. Nealand, and L Possner: An evaluation of ultraviolet radiation of sleeping quarters as supplement of accepted meth ods of disease control (American Journal of Hygiene, Septem ber 1948, p. 207). * Recent studies on disinfection of air in military establish ments (American Journal of Public Health, February 1947, p. 189). "Commercial exploitation of glycol vaporizers (American Journal of Public Health, February 1949, p. 222). "N. Pace, M. B. Fisher, J. E. Birren, G. C. Pitts, W. A. White, Jr., W. V. Consolazio, and L. J. Pecora: A Comparative Study of the Effect'.on'Men of Continuous Versus Intermittent Exposure to a Tropical Environment (Research Project X-205, Naval Medical Research Institute Report No. 2, May 1945). "F. K. Hick and M. M. Montgomery: Mechanism of Heat Retention (unpublished). "A. R. Behnke: Environmental and Physiologic Studies Aboard an Air-Cooled Hospital Ship En Route from Norfolk, Virginia, to Canal Zone (UJ5J5. Tranquility, AH-14, June 6-13 1945) (Research Project X-205, Naval Medical Research In stitute Report No. 4, September 1945). "G. E. Burch: The influence of environmental temperature and relative humidity on the rate of water loss through the skin in congestive heart failure in a subtropical climate (Ameri can Journal o) Medical Science, Vol. 211, 1946, p. 181). _G. Berenson and G. E. Burch: The responses of patients with congestive heart failure to rapid elevation in atmospheric temperature and humidity (American Journal of Medical Science, Vol.-223, 1952, p. 45). "Gunner Edstrom, G. Lundin, and T. Wramer: Investiga tion into the effect of hot, dry microclimate on peripheral circulation in arthritic patients (Annals of Rheumatic Diseases 7:76, June 1948). " Fundamentals of Anesthesia (American Medical Associa tion Press, Chicago, 1944, 2nd ed., p. 204). " B. A. Green: The hazard of fire and explosion in anesthesia (Anesthesiology 2:144, 1941). - *R. M. Tovell and A. W. Friend: Control of physical haz ards of anesthesia (Canadian Medical Association Journal 46: 560, 1942). "F. C. Houghten and W. L. Cook, Jr.: ASHAE Research Report No. 1111--Air conditioning requirements of an operat ing room and recovery ward (ASHVE Transactions, Vol. 45, 1939, p. 161). "A. R. Behnke and 0. Schneider: Unpublished naval stud ies (1940). "C. P. Yaglou and Ursula Wilson: Disinfection of Air by Air Conditioning Processes (American Association for the Advancement of Science! Publication No. 17, p. 129). "J. A. Reyniers; The control of cross-contamination by the use of mechanical barriers (American Association for the Ad vancement of Science, Aerobiology 17:254, 1942). "K. D. Blackfan, C. P. Yaglou, and K. McKenzie: The pre' mature infant: a study of the effect of atmospheric conditions on growth and on development (American Journal Diseases of Children 46:1175, 1933). "I. Rosenstern: Observations-on the control of respiratory contagion in the cradle (American Association for- the Advance ment of Science, Aerobiology 17:242, 1942). F. H. Krusen: Physical Medicine (W. B. Saunders Co., Philadelphia, 1941). . 14 F. C. Houghten, M. B. Federbcr, and Carl Gutbcrlet: ASHVE Research Report No. 1054--Fever therapy induced iiy conditioned air (ASHVE Transactions, Vol. 46, 1940, p. 131). M. B. Federber, F. C. Houghten, and Carl Gutberlet: ASHVE Research Report- No. 1161--Fever therapy locally induced by conditioned air (ASHVE Transactions, Vol. 46, 1940, p. 307). " L. W. Crossman and S. K. Safford: Refrigeration for an esthesia and therapy (The Modem Hospital 64:86, 1945). **B. Z. Rappaport, T. Nelson, and W. H. Welker: The ef fect of low relative humidity and constant temperature on pollen asthma (Journal of Allergy 6:111, 1935). ' " C. P. Yaglou: Hospital air conditioning ( The Environment and Its Effect Upon Man, Harvard School of Public Health, 1939, p. 244). "A. L. Barach: Principles and Practices of Inhalational Therapy (J. B. Lippincott Co., Philadelphia, 1944). J. G. M. Builowa: The Management of Pneumonia (Ox ford University Press, 1937, p. 260). "Cyril Tasker: What are the right conditions for comfort cooling? (Heating, Piping and Air Conditioning, August 1948, p. 84). "C. P. McCord and W. R. Witheridge: Odors Physiology and Control (McGraw-Hill Book Co., New York, 1949). BIBLIOGRAPHY R. P. Gaulin: Air conditioning the hospital (Reference Sec tion, Air Conditioning, Heating A Ventilating, January 1957, p. 73). W. W. Treichler, Jr.: Air conditioning the operating room (Air.Conditioning, Heating A Ventilating, April 1957, p. 73). CHAPTER 9 HEAT TRANSMISSION COEFFICIENTS OF BUILDING MATERIALS Heat Transfer Symbols; Calculating Overall Coefficient* Conductivity of Homogeneous Materials; Soil Corxfucfrv/fy and Specific Heat; Surface and Air Space Conductance; Overall Coefficients and Their Practical Use; Computed Coefficients of Waffs, Roofs, Ceilings, and Floors; Effect of Insulation; Combined Ceiling, Roof, . and Floor Coefficients; Glass Coefficient* Calculating Surface Temperatures HE design of air-conditioning or heating systems for character, and temperature of the boundary surfaces. Since Tbuildings requires a knowledge of the thermal properties the relationships are not linear, accurate values must be ob tained by test and not by computation. of the walls enclosing the space. (The term walla in this case, * emissivity; the ratio of the total radiant flux emitted by includes windows, doors, ceilings, floors, roofs, and skylights.) ' a surface to that emitted by an ideal black body at the Home The rate of heat flow through the walls under steady-state temperature. conditions at design temperatures is usually the basis for cal E " effective emissivity; the combined effect of the surface culating the heat required. For a given wall under standard conditions the rate is a specific value designated as (J, the overall coefficient of heat transmission or thermal transmittance. It may be determined by test in a guarded hot box apparatus, or it may be computed from known values of the thermal conductance of the various components. Because it is imprac emissivities of the boundary surfaces of an air space; the boundaries assumed to be parallel and of large dimensions as compared to the distance between them. ' r = surface reflectivity; the ratio of the radiant flux reflected by an opaque surface to that falling upon it. R " thermal resistance. Its value is obtained from the re ciprocal of heat transfer as expressed by U, k, C, f, or a. It ticable to test all combinations of building materials, the pro cedure and necessary data for calculation of the value of U are given in this chapter, together with convenient tables of computed values for a large number of the more common constructions. may be expressed in (Fahrenheit degrees per Btu)/(hour) (square foot). For example, a wall with a U value of 0.25 would have a resistance value of R " 1/0.25 -- 4-0 ru. The word ru has been suggested as an abbreviation for resistance unit. ' CALCULATING OVERALL COEFFICIENTS HEAT TRANSFER SYMBOLS U -- overall coefficient of heat transmission or thermal trans mittance (air-to-air); the time rate of heat flow expressed in Btu per (hour) (square foot) (Fahrenheit degree temperature difference between air on the inside and air on the outside of a wall, floor, roof, or ceiling). The term is applied to the usual combinations of materials, and also to single materials, such as window glass, and includes the surface conductance on both sides. This term is frequently called the U value. . k = thermal conductivity: the time rate of heat flow through a homogeneous material under steady conditions per unit tem perature gradient through unit area perpendicular to the tem perature gradient. Its value is expressed in Btu per (hour) (square foot) (Fahrenheit degree per inch of thickness). Mate rials are considered homogeneous when the value of k is not af fected by variation in thickness or size of sample withia the range normally used in construction. C = thermal conductance; the time rate of beat flow through a unit area of a material from one of its surfaces to the other per unit temperature difference between the two surfaces. Its value is expressed in Btu per (hour) (square foot) (Fahrenheit depee). The term is applied to specific materials as used, either homogeneous or heterogeneous, for the thickness or construetion stated, not per inch of thickness. '/ * film or surface conductance; the time rate of heat flow between a unit area of a surface and the surrounding air. Its value is expressed in Btu per (hour) (square foot of surface) (Fahrenheit degree temperature difference). Subscripts * and o are used to differentiate between inside and outside surface conductances, respectively. a = thermal conductance of an air space; the time rate of heat flow-through a-unit area of an air space per unit tempera ture difference between the boundary surfaces. Its value is ex pressed in Btu per (hour) (square foot of area) (Fahrenheit degree). The conductance of an air space is dependent on the temperature difference, the height, the depth, the position, From Chapter 5, Equation 7, the total resistance to heatflow through a wall is equal numerically to the' sum of the resistances in series. . Rt = Ri + Rt + R* + + + (1) where Ri, Rt, etc., are the individual resistances of the wall components, and RT is total resistance. For a wall of a single homogeneous material of conduct ivity k and thickness x with surface coefficients /; and /., Rt (2) Then by definition, U -- l/Rr For a wall with air space construction and consisting of two homogeneous materials of conductivities i and kt, thick nesses Xi and Xt, respectively, and separated by an air space of conductance a, fJr"/T<+ *",+-*+-- + /". and U = l/Rr (3) For-types of building materials having non-uniform or ir regular sections such as hollow clay tile or concrete blocks, it is necessary to use the conductance C of the section unit as manufactured instead of a conductivity k. The resistance of the section 1/C is therefore substituted for x/k in Equations 2 and 3. It will be noted that in order to compute the U value of a construction it is first necessary to know the conductivity 94 CHAPTER 9 1959 Guide end thiftknpffi of the homogeneous material, the conductance of non-homogeneous materials (such as concrete blocks), the surface conductances of both sides of the construction, and the conductances of any contained air spaces. These items are discussed in the pages that follow. Conductivities and Conductances . The method of calculating the overall coefficient of heat transmission for a given construction is comparatively simple, but accurate values of conductivities and conductances must be used to obtain satisfactory results. In addition, there are sometimes parallel heat-flow paths of different resistances in the same wall, and these may necessitate modification of the formula. In such calculated results should be checked by test. . The determination of the fundamental conductivities and conductances requires considerable skill and experience to ob tain accurate results. It is recommended that thermal con ductivities of homogeneous materials be determined by means of the Guarded Hot Plate.1 For determination of conduc tances, a Guarded Hot Box method* is generally used. Conductivity of Homogeneous Materials ' Thermal conductivity is a property of a homogeneous ma terial and of types of building materials such as lumber, brick, and stone/ which may be considered homogeneous. Most insulating materials, except reflective types, are of a porous nature and consist of combinations of solid matter with cm^H voids. Such materials including fibrous, cellular, or granular matter are generally known as mass or bulk in sulations. The thermal conductivity of these materials will vary with density; mean temperature; size of voids, fibers, or particles; degree and extent of bond between particles; mois ture present; and the arrangement of fibers or particles within the material. '- The effect of density upon conductivity (at constant mean temperature) is illustrated for two fibrous materials in Fig. 1. Typical variation of conductivity with mean temperature is shown in fig. 2. Thermal Conductivity of Soil The following statements are based largely on results of a study* made in the Engineering Experiment Station, Uni versity of Minnesota, and published in Bulletin No. 28. Tests were made on nineteen different soils which represented a wide textural variety, including gravel, sand, sandy loam, tilt loam, and clay, as well as some crushed rocks and a fibrous peat. Moisture contents in tests varied from air-dried values T te ta &it i# V S*n? n 2 >CHSITV *oumos c roo r Fig. 1 .... Typical Variation of Thermal Conductivity with Density-- for Fibrous Material fig. 2 .... Typical Voriotion of Thermal Conductivity . . with Mean Temperature to those greater than the optimum moisture content; densi ties varied from a loosely-poured condition to the maximum density obtainable by heavy ramming. The general findings of the investigation are as follows: Effect of Temperature. Soils were tested at several mean temperatures. The degree of influence of temperature depends upon whether it is above or below freezing. For increases of moisture content exceeding about 6 to 12 percent, the conduc tivity of frozen soil becomes progressively greater than that of the unfrozen soil. Effect of Density. Density affects the thermal conductivity of a soil in about the manner for all soils, at any moisture oontent, and for either the frozeo or unfrozen condition. On the average, each one pound per cubic foot increase in dry density increases the thermal conductivity by about 3 per cent. Effect of Moisture. An increase in moisture content, up to the point of saturation, causes an increase in thermal con ductivity. The rate of increase in typical soils was as follows: average conductivities, in Btu per (square foot) (hour) (Fahrenheit degree per inch), of four sands at a density of * 110 lb per cu ft were: 6.8 at 2.5 percent moisture, 8-9 at 5 percent moisture, 11.2 at 10 percent moisture. Jive soils of a fine texture at a density of J 00 lb per cu ft, gave average con ductivities of 6.7 at 10 percent moisture, and 9.5 at 20 per cent. Thus, the doubling of moisture content within the ranges cited increases the conductivity by approximately 30 or 40 percent. At higher moisture contents the percentage increase would be less. ' Effect of Soil Characteristics. The thermal conductivity of the soil, at a given density and moisture content, varies in general with the texture of a soil, being relatively high for coarse-textured soils and relatively low for fine-textured soils. The mineral composition of the soils also affects the conduc tivity. Quartz tends to give high values, whereas minerals such as plagioclase-feldspar and pyroxene, which are constituents of basic rocks tend to give low values of thermal conductivity. These points are illustrated by the values in Table 1 which lists seventeen soils in approximate order of their magnitude of thermal conductivity from greatest to least for seven dif ferent density-moisture content conditions. Some of the values in this table have been determined by extrapolation and are consequently approximate. Blank spaces in the table indicate that the density or moisture content, or both, are such that no tests were possible for that condition or that no tests were sufficiently close to permit a reasonable extrapolation of the data. Granular soils, particularly those with high quartz con tents, head the tabulation or have the greatest conductivity Heat Transmission Coefficients of Building Materials 95 Table 1 .... Thermal Conductivity (lc) Values of Soils In Approximate Order of Decreasing Values* ~ Mean Temporulvro--40 F ' Sod Designation Mechanical Anefyw % by Weight Gravel sat Cloy Over 2.0 mm 05 to 2.00 mm Fine Crushed Quartz....................... 0.0 Crushed Quarts................................. 15:5 Graded Ottawa Sand....................... . 0.0 Fairbanks Sand.................................. 27.5 Lowell Sand........................................ 0.0 - 100.0 79.0 99.9 70.0 100.0 Chens River Gravel..................... Crushed Feldspar.............................. Crushed Granite........................ Dakota Sandy Loam................ Crushed Trap Rock.......................... 80.0 25.5 16.2 10.9 27.0 19.4 70.3 77.0 57.9 63.0 Ramsey Sandy Loam....................... Northway Fine Sand............... Northway Sand.......................... Healy Clay.......................................... Fairbanks Silt Loam................ 0.4 0.0 3.0 0.0 0.0 53.6 97.0 97.0 1.9 7.6 Fairbanks Silty Clay Loam.. Northway SiJt Loam........................ 0.0 1.0 9.2 21.0 - Btu per (iqiare foot) (hour) (Fahrenheit decree per inch). 0.005 to Under 0.05 nua 0.005 mm 0.0 0.0 5.5 0.1 2.5 0.0 0.0 0.6 4.2 * 6.8 21.2 10.0 10.0 27.5 3.0 0.0 20.1 80.9 18.5 0.0 0.0 78.0 11.5 63.8 64.4 27.0 13.6 4 100 110 12.0 11.5 10.0 8.5* 8.5 16.0 10.5 11.0 6.0 5.5 5.0 4.5 4.5 4.5 4.0* 6.0 6.0 Morthwe Content--% 10 Dry Donsity-fb per cu ft 120 90 110 20 90 100 13.5 7.0 5.0 9.0* 7.5 10.0 4.0* 7.0* 6.0* 7.0* fig. 3 .... Determining Thermal Conductivity of Soils . from Density and Moisture Content at a given condition. Sandy loam soils are midway in the table and fine grained soils such as clay and silt loam are last. Estimating Thermal Conductivity. The four diagrams of Fig. 3 are presented to aid in the estimate of the thermal con ductivity of any soil. Two of the charts are for sands or sandy soils, and two for silt and clay soils. One of the diagrams for each type of soils is for the frozen, and the other for the un frozen condition. It is expected that these charts will give conductivity values with a precision of 25 percent. The effect of such factors as density, moisture content, freezing, or tex ture may be easily approximated by use of these graphs. Specific Heat of Soils Tests to determine specific heat were run on twelve soils. On five of the soils, tests were made at three or four mean temperatures varying from about 10 to 140 F. The specific heat values of all twelve Mils varied by only a small amount (about 0.01), and averaged 0.19 at 140 F. The specific heat values of the soils decreased with a decrease in. temperature. The average value'at zero F would be about 0.16: Values at temperatures between zero and 140 F can be estimated by considering a straight-line relationship between the two values given. ' Surface Conductance The surface conductance of a wall is the combined beat transfer to or from the wall by radiation, convection, and con duction. Each of the three portions making up the total may vary, independently of the others, thus affecting the total conductance. The heat transfer by radiation between two surfaces is controlled by the character of the surfaces (emis- sivity), the temperature difference between them, and the solid angle through which they see each other. -The heat transfer by convection and conduction is controlled by the roughness of the surface, by air movement, and temperature difference between the air and the surface. . '- The importance of the effect of temperature of surrounding surfaces on the surface conductance, due to the effect on radia- 96 CHAPTER 9 1959 Guide Table 2 .... Variation in Surface Conductance Coefficient for Vertical Surfaces with Different Temperatures of Surrounding Surface Surrounding Sartot* lemparofurv 75 F 70 F 69 F 60 F 50 F Convection--Btu per (hr) (sq ft). 6.6 6.6 6.6 6.6 6.6 Radiation--Btu per (hr) (sq ft).. 4.4 8.6 9.6 17.0 24.9 Total--Btu per (hr) (sq ft) ----- 11.0 15.2 16.2 23.6 31.5 tion, is illustrated in Table 2, which applies to a vertical sur face at 80 F, with ambient air at 70 F and with radiation exchange corresponding to an effective emissivity of 0.83.* In many cases, because the heat resistance of the internal parts of the wall is high compared with the surface resistance, the surface factors are of minor importance. In other cases, e.g., single glass windows, the surface resistances constitute almost the entire resistance and are therefore very important. An analysis of various factors affecting surface conductance and the difference between surface and air temperatures will be found in Reference 5. (See also Chapter 30.) ' The convection part of the surface conductance is affected markedly by air movement. This is illustrated by Fig. 4, which shows the results of tests*, made on 12-in. square samples of different materials at a mean temperature of 20 F, and for wind velocities up to 40 mph. These conductances include the radiation portion of the coefficient which, for the conditions of the teste, was about 0.7 Btu per (hr) (sq ft) (F deg). More recent teste7 on smooth surfaces show that surface length also affects significantly the convection part of conductance; the average value decreases as the surface length increases. More over, observations* of the magnitude of low temperature radi ant energy received from outdoor surroundings show that only under certain conditions may the out-of-doors be treated as a black body radiating at air temperature. - Because of these factors, the selection of surface conduc tance coefficients for a practical building becomes a matter of judgment. Surface conductances are shown in Tables 3 and 4. In calculating the overall heat transmission coefficients for the waffs, etc., of Tables 5 through 16, the appropriate indoor and outdoor surface coefficients given in Table 4 for Air Surfaces have been used. Both values combine the effects of convection and radiation, and are applicable to ordinary building ma terials. They should not be used for low emissivity surfaces such as bright metal. For exposed reflective surfaces refer to Table 3, Section A, and to footnotes under Table 16. In special cases, where surface conductances become im portant factors in the overall rates of heat transfer, more-se lective coefficients may be required. Principles and data given in Chapter 5, Heat Transfer, may be applied-in such cases; Air Space Conductance The transfer of heat across an air space involves the bound ary surfaces as well as the intervening air, and depends mark edly on the orientation of the air space and the direction of heat flow. The coefficients given for air space conductance represent the total conductance from one surface bounding the air space to the other. The total conductance is the sum of a component due to radiation and a component due to con vection and conduction combined. These components may vary independently of each other. The radiation portion of the coefficient is affected by the temperature o! the two boundary surfaces, and by their re spective surface emissivitics e, the combined effect of which is expressed by means of the effective emissivity E of the air space. The radiation component is not affected by the thickness of the space or by its orientation or direction of heat flow. The heat transfer by convection and conduction combined, how ever, is markedly affected by the orientation of the air space and the direction of heat flow, is significantly affected by the temperature difference across the space and in some cases by the thickness of the space, and is affected to only a small extent by the mean temperature of its surfaces. For air spaces usually employed in building construction, the radiation and convection-conduction components may vary independently of each other. - Table 3, Section C, gives the thermal conductances ahd resistances of air spaces of uniform thickness and moderately 20 F Mean Temperature smooth surfaces, based on experimental measurements con ducted at the National'Bureau of Standards.' Although the conductances of air spaces vary to some extent with thick ness in the range oyer % in., average values are tabulated for the range from % in. to 4 in., for all except horizontal spaces with heat flow downward. The error involved by averaging is less than 10 percent in the extreme case and less than 5 per cent in most. For more exact values Reference 9 may'be con sulted. . . , For narrow air spaces, which may be defined as those for which the product of the cube of the thickness of the space in inches times the: temperature difference (Fahrenheit de grees) across the space is less than 3 for heat flow horizontally or downward, or less than 1 for heat flow upward) the con ductance is the sum of the radiative heat transfer coefficient and that' for conduction alone through air, since convection is practically suppressed. The radiation component can be computed by means of Equation 4 and Table 4 of Chapter 5; the conduction component can be computed using the con~ Heat. Transmission Coefficients of Building Materials . 97 ductivity of air at the appropriate mean tempearture (see Table 1, Chapter 5). The effects of different mean temperatures, temperature differences, and effective emissivitics are indicated in Table 3 of this chapter, Section C. As indicated, use may be made of interpolation and moderate extrapolation of conductance values in the table to obtain conductances for conditions moderately different from those given. Interpolation of re sistance' values is not recommended, especially in relation to emissivity values. Table 3, Section B, gives values for the surface reflectivities and emissivities of materials used as boundaries of air spaces in building construction, for total radiation at ordinary build ing temperatures. Effective emissivities for various combina tions of these materials, for use in conjunction with Section C of Table 3, are given in the last two columns of Section B. When considering heat transfer across air spaces in building construction, the emissivities of the boundary surfaces must be known. The possibility of change in emisivity of highly reflective surfaces due to exposure to conditions promoting chemical action, deposition of dust, soiling of the surface, or the application of coatings, even though transparent to the eye, must be considered in selecting a material for use.10 Surface emissivity values should be obtained by teste. Building Materials and Structures Report BMS 151, National Bureau of Standards. In order to provide a reasonable factor of safety to account for departures of construction from exemplary conditions, in part due to field construction re quirements and practices, some may wish, before making corrections for framing (as indicated in Fig. 6), to increase moderately the calculated U values of the insulated walls, floors and ceiling sections obtained from Table 16. Where reflective air spaces are involved, increases of U values up to 10 percent for applications where heat flow is horizontal or upward, and up to 20 percent where heat flow is downward, appear reasonable on the basis of present information. Computed Heat Transmission Coefficients In the analysis of any wall construction for the puropse of calculating the overall coefficient of heat transmission U, it is first necessary to determine the paths of heat flow, that is. OVERALL COEFFICIENTS AND THEIR PRACTICAL USE The values in Tables 3 and 4 for component elements and materials were selected by the ASHAE Technical Advisory Committee on Insulation as representative for dry materials at 75 F mean temperature. They are based oh available pub lished data obtained by the guarded hot plate method (ASTAf C177-45) or by the guarded hot box method (ASThf C236- 54T). Because there are variations in commercially available materials of the same type, not all of these selected represen tative values will be in exact agreement with data for indi vidual products. The exact value for a certain manufacturer's material can be secured from unbiased teste or from guaran teed data of the manufacturer. The most exact method of determining the beat transmis sion coefficient for a given combination of building materials assembled as a building section is to test a representative section in a guarded hot box. However, it is not practicable to test all the combinations which may be of interest in building construction. Experience has indicated that U values for many constructions, when calculated by the methods given in this chapter, using accurate values for the component materials, are in good agreement with values determined by guarded hot box measurements. ' Caution . Although the validity of calculating U values for all of the types of constructions in Tables 5 through 16 has not been fully demonstrated, calculated values are given because measured values are not available. It is emphasized that the calculated values in Tables 5 through 16 are given for the convenience of the user. In calculating U values, exemplary conditions of compo nents and installations are assumed, i.e., that insulating ma terials are uniformly of the nominal thickness and conduc-. tivity, that air spaces are of uniform thickness and surface temperatures, that effects due to moisture are not involved, and that installation details are in accordance with design. Some evidence of departures of measured values from cal culated values for certain insulated constructions is given in Fig. 5 .... Section of Concrete Wall Having Steel Tie Rods and Insulation whether they are parallel or series, or a combination of both. This is in accordance with the basic laws of heat transfer which state that in parallel flow the conductances are additive, while in series flow the resistances are additive. Likewise, in order to determine the total resistance for the wall, the conductance must be known. - The importance of this analysis cannot be overemphasized. This is especially true in wall constructions in which there are parallel paths of heat flow, and one path has a high heat transfer while others have a low heat transfer. The method of making this calculation can best be shown by Example 1 and Fig. 5. As this wall was tested by the hot box method at the University of Minnesota, a direct comparison can be made between calculated and tested values. Example 1: Calculate the coefficient of heat transmission U for a wall shown in Fig. 5- Wall construction consists of two 4-in. concrete walls separated by a 2}-in. space filled with in sulation ; diameter metal tie rods are embedded a dis tance of 1 in. in each 4-in. concrete wall, and spaced 9 in. ver- ' tically and 12 in. horizontally. Values of k are: insulation 0.30, . concrete 12.00, tie rods 400.00. .. "'` ' (Continued &n p. /OS.) ' 98 CHAPTER 9 1959 Guide Table 3 .... Surface Conductances and Resistances for Still Air AO conductance values jspretsed ta Btu per (hr) (jq ft) (F deg tamp <ff] SECTION A. Surface Conductances for Still Air*- SECTION 8. Reflectivity and Emitsivify Vaiues of Various Surfaces* and Effective Etmsslvitic* of Air Spoccs Scrfoce Eouttivify Posfion of Surface Direction of Non- Heat Flew reflectfve Reflective Reflective t - o.vo t = 0.20 * - 0.05 c RC R CR Surface effective Emitavity E of Air Space Reflectivity in percent Average Emrsdnty With one surface hav With both ing emo surfaces of tivity and embsivity < other 0.90 Horizontal.............. Upward 1.63 0.61 0.91 1.10 0.76 1.32 Aluminum foil, bright.... 92 to 97 Sloping--45 deg.. . Upward 1.60 0.62 0.88 1.14 0.73 1.37 Aluminum sheet................... 80 to 95 Vertical.................... Horizontal 1.46 0.68 0.74 1.35 0.59 1.7C Aluminum coated paper. polished.............................. 75 to 84 Sloping--45 deg... Downward 1.32 0.76 0.60 1.67 0.45 2.22 Steel, galvanized, bright.. 70 to 80 Horizontal............... Downward 1.08 0.92 0.37 2.70 0.22 4.55 Aluminum paint.................. Building materials; wood, paper, class, masonry. nonmetallic paints......... 30 to 70 5 to 15 0.05 0.12 0.20 0.25 0.50 0.90 0.05 0.12 0.20 0.24 0.47 0.82 0.03 0.06 0.11 . 0.15 , 0.35 0.82 * For ventilated mttica or spaces above ceilings aoder summer condition* (beat flow down) tee Table 17. - b Conductances areforaarfaceaof the statedetctaahrity lacing surroundings having anemotivity equal to 0.9 and at the anno temperature at the ambient air. Values are baaed on a surface-sir temperature difference of 10 de and for surfsee temperature of 70 F. (See Table 4 for surface conductsoca for moving air.) * See also Chapter 5, Table S. SECTION C Thermal Conductance* and Resistances of a Plano*-* Air Space* Position of Air Space Heat How ' - . Air Space Thermal Coodnctance-C Value of E- Thermal Redsfance-R Value of E Thickness ,* Mean temp,1 F Temp diff* deg 0.05 0.2 0.5 0.82 0.05 0.2 0.5 0.82 Horiz. Up X to4 50 10 0.41 0.55 0.82 1.11 2.44 1.83 1.22 0.90 50 ' 30 0.54 0.68 0.95 1.24 1.84 1.47 1.05 0.80 00 10 0.41 0.58 0.92 1.28 2.47 1.73 1.09 0.78 45 Slope Up X to 4 50 50 90 10 0.35 0.49 0.76 1.05 2.84 2.05 1.31 0.95 30 0.48 0.62 0.89 1.18 2.08 1.62 1.13 0.85 10 0.35 0.52 0.86 1.23 2.85 1.92 1.16 0.81 Vert. Horiz. X to4 50 50 90 10 . 30 10 0.28 0.38 0.29 0.42 0.52 0.46 0.69 0.79 0.80 0.99 1 08 1.16 3.52 2.64 3.49 2.37 1.94 2.19 1.44 1.27 1.25 1.02 0.92 0.86 45 Slope Down X to4 50 50 90 10 0.24 0.38 0.65 0.94 4.14 2.65 1.54 1.06 30 0.30 0.43 0.71 1.00 3.36 2.30 1.41 1.00 10 0.25 0.42 0.76 1.12 4.07 2.40 1.32 0.89 Horiz. Down* X IX 4 50 . 50 50 20 20 20 0.28 0.42 0.18 0.31 0.11 0.25 0.69 0.98 0.58 0:87 0.52 0.81 3.57 5.56 8.94 2.38 3.23 4.03 1.45 1.73 1.92 1.02 1.15 1.23 X 90 IX 90 4 90 20 0.31 0.48 0.82 1.18 3.23 2.08 1.22 0.85 20 0.20 0.37 0.71 1.07 5.00 2.70 1.41 0.93 20 0.13 0.30 0.64 1.01 7.82 3.35 1.56 0.99 Notes: * Space* at uniform tbicfcneaa, bounded by moderately smooth surface*. Where a ranee of thickness b given, the given conductance b the average over the range; extreme value* within the range differ therefrom by less ta> jo peroent. * 1 Interpolation, and moderate extrapolation, of conductance value* are permissible for other value* of mean temperature, temperature difference and effective embaivity B. . Effective embaivity of apace, B, b given by - -- --I------- 1 when a and ware the embmritias of the surfaces of the air apace. (See Section B, above.) ' " *i * ( k The conductances of horiaoDtal spaces with beat flow downward are substantially independent of temperature difference. - * Baaed on National Bureau of Standards data presented in Hetuu*# Btmarck Paper No. 32, Homing and Home Finance Agency, U&4 (U. S. Government Printing Office, Washington, D. C.). / Heat Transmission Coefficients of Building Materials 99 Table 4 .... Conductivities (fc), Conductances (C), and Resistances (R) of Building and Insulating Materials (Design Values)* These constants are expressed m Bta per (hoar) (square foot) (Fahrenheit degree temperature difference). ConducAnYbs (k) are per rbdr ttudeness and, conductances (C) ore for fhrcknoss or construction stated, not per inch fhtcinew Afatarfaf Description Density (lb per Cu Ft} Conductivity or Resistance (R) Per inch For G) Cc)W (CJ thickness Bated AIR SPACES* See Table 1--Section B Position Heat Flow Horizontal........... Up (winter)......................... Horizontal....... Up (summer)..................... Horizontal.......... Down (winter).................... Horizontal.......... Down (winter).................... Horizontal.............Down' (winter).................. Horizontal..............Down (winter).................. Horizontal..............Down (summer)............... Horizontal..............Down (summer)............... Horizontal;............Down (summer)................ Sloping, 45.........Up (winter)............. :.......... Sloping, 45...........Down (summer)................ Vertical..................Horiz. (winter).................. Vertical.................. Horiz. (summer)............... Thickness ----- X-A in. K: ........ IX in. ...........X in. ......... IX in. .............4 in. ....%-A in. ----- X-4 in. ----- X-4 in. ------ X-* in- =. AIR SURFACES* Still Aih 15 MPH WlNP 7X mph Winp : See Table 1--Section A Position Heat Flow Horizontal............................................................ ................ Up Up Sloping (45)....................................................... ................ Up Vertical........................................................................... Sloping(45).................................................................. Horizontal............................................................. Any position--any direction (for winter). Aoy position--any direction (for summer) 5 BUILDING BOARD* Boards, Panels, Sheathing, Etc. BUILDING PAPER FLOORING MATERIALS Asbestos-cement board............................................................... - - - Asbestos-cement board..................................................................Xn. Gypsum or plaster board............................................................. Xin. Gypsum or plaster board...................... X >n- Plywood............................................................................................... . Plywood...................................................................................................Xin Plywood...................................................................................................Xin. Plywood......................... X in Plywood or wood panels............................................................ Xia- Wood fiber board, laminated or homogeneous........... ........ j Wood fiber--hardboard type............................................................ Wood fiber--bardboard type................................................ Xin. Wood--fir or pine sheathing...................................................*Xlin. Wood--fir or pine............................................................................IXin. 120 50 50 34 34 34 34 26 31 65 65 Vapor--permeable felt.......................................... Vapor--seal, 2 layers of mopped 15 lb felt Vapor--seal, plastic film................................. -- -- ~ Asphalt tile........................................................ '... Carpet and fibrous pad........................................ Carpet and rubber pad........................................ Ceramic tile............................................................... Cork tile. .. ....................................................... ... Felt, flooring..........-................................................. Floor tile or linoleum--av. value........ Linoleum............................................................. Plywood subfloor.............................................. ..............X inRubber or plastic tile........................................... Wood subfloor........................................................... ......... nWood, hardwood finish....................................... ..............k io. 120 -- -- -- 25 -- -- - -- 80 -- 110 -- -- -- . 4.0 0.80 0.42 0.50 1.40 _ -- -- _ -- -- -- 0.45 -- -- -- -- -- -- -- -- .-- INSULATING MATERIALS Blanket and Bait Cotton fiber*........................................................ Mineral wool, fibrous form, processed from rock, slag, or Wool fiber*.................................................................. Wood fiber, multilayer, stitched expanding*....................... 0.S-2.0 3.2~3;6 1.5-2.0 0.28 0.25 0.27 1.18 1.28 0.98 0.87 0.81 0.80 1.18 1.07 1.01 1.11 1.12 1.03 2.16 1.63 1.60 1.46 1.32 1.08 6.00 4.00 33. 3.10 :2.25 3.20 2.12" 1.60 1.07 5.60 1.02 0.49 16.70 8.35 -- 24.80 0.48 0.81 12.50 -- 3.60 16.70 20.00 12.00 1.28 42.40 12.50 1.02 .1.47 -- -- -- -- 0.25 1.25 2.38 2.00 0.72 -- -- -- -- -- -- -- 2.22 -- --. -- -- -- -- -- -- _ 3.85 4.00 3.70 0.85 0.78 1.02 1.15 1.23 1.25 0.85 0.93 0.99 0.90 0.89 0.97 0.86 0.61 0.62 0.68 0.76 0.92 0.17 0.25 0.03 0.32 0.45 0.31 0.47 * 0.63 0.94 0.18 0.98 2.03 0.06 Negl 0.04 2.08 1.23 0.08 -- 0.28 0.06 0.05 0.08 0.78 0.98 0.68 -- -- too CHAPTER 9 1959 Guide Table 4 .... Conductivities (Jr), Conductances (C), and Resistances (R) of 8uilding and insulating Materials (Continued) . (Design Vafties)* Description Density (lb per Co ft) Conductivity or Conductance ftrfdOAC* { G) G)w . (Cl Per indi thickness For thickness listed Board Board and Slabs Loose Fill ROOF INSULATION MASONRY MATERIALS Concretes MASONRY UNITS G1&S3 fiber.............................................. Wood or cane fiber Acoustical tile*............................... . Acoustical tile1.................................. Interior finish (plank, tile, lath). Interior finish (plank, tile, lath). Roof deck slab Approx.................................................. Approx.................................................. Approx................................................. Sheathing (impreg. or coated)....... Sheathing (impreg. or coated)........ Sheathing (impreg. or coated)........ X in. X io- X in- 1M in. . .2 in. X in. in- Cellular glass................................................................. Corkboard (without added binder)...................... Hog hair (with asphalt binder).............................. Plastic (foamed)........................................................... Wood shredded (cemented in preformed slabs). 9.5 _ -- 15.0 15.0 _ -- -- 20.0 20.0 20.0 9.0 6.5-8.0 8.5 1.62 22.0 0.25 _ -- 0.35 -- _ -- -- 0.38 -- -- 0.40 0.27 0.33 0.29 0.55 Macerated paper or pulp products. .. Mineral wool (glass, slag, or rock).. Sawdust or shavings................................ Vermicuiite (expanded).......................... Wood fiber: redwood, hemlock, or fir. 2.5-3.5 2.0-60 8.0-15.0 7.0 2.0-3.5 0.28 0.30 0.45 0.48 0.30 All types* Preformed, for use above deck Approx.......................................... Approx.......................................... Approx.......................................... Approx.......................................... Approx.......................................... Approx.......................................... Xin ...t in .IX in...2 in. .2H in. ...3 in. --.-- ---- ---- ---- ---- Cement mortar............................................................................... Gypsum-fiber concrete 873^%gypsum, 12W% wood chips Lightweight aggregates including expanded shale, clay or slate*, expanded slags; cinders; pumice; perlite; vermicuiite; also cellular concretes Sand and gravel or stone aggregate (oven dried) Sand and gravel or stone aggregate (not dried).. Stucco.................................................................................. 116 51 120 100 80 60 40 30 20 140 140 116 5.0 1.66 5.2 3.6 2.5 1.7 1.15 0.90 0.70 9.0 12.0 5.0 Brick, common................................... Brick, face........................................... Clay tile, hollow: 1 cell deep........................................ 1 cell deep........................................ 2 cells deep..................................... 2 cells deep..................................... 2 cells deep..................................... 3 cells deep.................!.................. Concrete blocks, three oval core: Sand and gravel aggregate.... Cinder aggregate. Gypsum partition tile: 3 x 12 x 30 in. solid.. 3 x 12 x 30 in. 4-eell. 4 x 12 x 30 in. 3-cell. 3 in .4 in . .6 in .8 in .10 in 12 in .4 in .8 in 12 in 120 130 _ -- -- ---- -- -- -- -- -- -- -- _ -- 5.0 9.0 __ -- -- -- -- -- __ -- -- -- -- --- -- __ -- -- - 0-84 0.56 -- 0.70 0.24 0.18 0.12 --0.76 0.49 _ -- -- --- -- __ -- -- -- -- 4.00 _ -- 2.88 -- _ -- -- 2.63 -- -- 2.50 3.70 3.00 3.45 1.82 3.57 3.33 2.22 2.08 3.33 - 1.19 1.78 -- 1.43 4.17 5.56 8-33 -- 1.32 2.06 __ --. -- -- -- _ -- -- -- -- 0.72 Q.36 0.24 0.19 0.15 0.12 __ -- -- -- -- -- ---- -- -- -- -- __ -- 1.25 0.90 0.66 0.M 0.45 0.40 1.40 0.90 0.78 1.16 0.90 0.58 0.53 0.79 0.74 0.60 -- -- -- -- -- 0.20 0.60 0.19 0.28 0.40 0.59 0.86 1.11 1.43 o.u 0.08 0.20 0.20 0.11 ------__ -- -- _ -- -- -- -- .-- _-- -- 1.39 2.78 4.17 5.26 6.67 8.33 _ -- -- -- -- -- -- -- -- -- -- -- -- 0.80 1.11 1.52 1.85 2.22 2.50 0.71 1.11 1.28 0.86 1.11 1.72 1.89 1.28 ^ 1.35 J 1.67 Heat Transmission Coefficients of Building Materials 101 Table 4 .... Conductivities (k), Conductances (C), and Resistances (R) of Building and Insulating Materials {Concluded) {Design Valves)* . Material Description Denaly (lb per Cuftl Conductivity or Conductance Redstone* 00 G) G)<fc> (O Per inch thickness for thickness . listed MASONRY UNITS (Continued) Lightweight aggregate (expanded shale, clay, f 3 in. slate or slag; pumice)..........................................< | !" . (12 in! Stone, lime or sand....................................................................... M ill 12.50 0.79 0.67 0.50 0.44 0.08 1.27 1.50 2.00 2.27 METALS (See Chapter 5, Table 1) PLASTERING MATERIALS Cement plaster, sand aggregate............................................... Sand aggregate.............................................................. in. Sand aggiegate.............................................................. X in Gypsum plaster: Lightweight aggregate................ :..............................in. Lightweight aggregate--...................................... % in. Lightweight agg. on metal lath.................-.........in. Perlite -aggregate....................................................................... Sand aggregate........................................................................... Sand aggregate.............................................................. X ioSand aggregate.............................................................. % in. Sand aggregate on metal lath..................................X in. Sand aggregate on wood lath................................................ Vermiculate aggregate............................................................. ROOFING , Asbestos-cement shingles........................................................... Asphalt roll roofing....................................................................... Asphalt shingles............................................................................. Built-up roofing.................. ....................-........................X in. Slate......................................................................................X in. Sheet metal................................................................................... Wood shingles................................................................................. SIDING MATERIALS (On Flat Surface) Shingles " Wood, 16-in. 7H-in. exposure............................................... Wood, double, 16-in., 12-in. exposure................................ Wood, plus insul. backer board.............................X* in. Siding Asbestos-cement, X *n* lapped.......................................... Asphalt roll siding.................................................................... Asphalt insulating siding M in. bd.)................................ Wood, drop. 1 x 8 in................................................................ Wood, bevel, X * 8 in., lapped............................................ Wood,J>eveL X * 10 m., lapped.......................................... Wood, plywood, % in., lapped............................................. Structural glass..'.......................................................................... WOODS Maple, oak, and similar hardwoods....................................... Fir, pine, and similar softwoods.............................................. 116 -- ~ 45 45 -- 45 105 105 105 -- -- 45 120 70 70 70 -- -- -- 5.0 -- -- -- -- -- 1.5 5.6 -- -- -- __ 1.7 -- -- -- -- 400+ -- _ 10.00 6.66 3.12 2.67 2.13 -- -- 11.10 9.10 7.70 2.50 -- 4.76 6.50 2.27 3.00 20-00 -- 1.06 -- -- 1.15 __ -- 0.84 -- -- 0.71 -- -- -- --__ -- -- -- -- -- -- __ -- -- -- 45 1.10 32 0.80 4.76 6.50 0.69 1.27 1.23 0.95 1.59 10.00 __ -- 0.20 -- -- -- -- -- 0.67 0.18 -- -- -- -- 0.59 _ ___ -- -- -- Negl -- __ -- ---- ---- __ -- -- 0.91 1.25 _ 0.10 0.15 0.32 0.39 0.47 -- -- 0.09 0.11 0.13 0.40 0.21 0.15 0.44 0.33 0.05 0.94 0.87 1.19 1.40 0.21 0.15 1.45 0.79 0.81 1.05 0.59 0.10 -- * Representative vnhws tor dry material* at 79 F mean temperature, (elected by tbe ASHAF. Technical Advisory Committee on Insulation- They are intended e* deeicn (not specification) values for materials of building construction in normal use. For conductivity of a particular product, the user may obtain the value supplied by the manufacturer or secure tbs insults of ,,f*w,rir--t tats. I- Air space resistance value*shown here are for epaea laced both sides with ordinary nanrtfiectae materials (* -- 0.&0 and E 0.82) and are based on following con ditions: Winter--60 F mean temperature and 20 deg temperature difference, Summer--00 F mean temperature and 10 deg temperature diflerence except for borbontal airspace with beet flow downward which is based on ?0 deg temperaturedifference. * Surface resistance values shown here are for ordinary narmfiectiee materials ( -- 0.90). . ' d See also Insulating Materials, Board. * Includes paper becking and facing if any. In cases where the insulation forms a boundary (highly reflective or otherwise) of an air space, refer to Table 2, Sections B and C. to obtain the insulating value of the air space for theappropriate effective enussivity and temperature condition* of the specs. Insulating values of acoustical tile vary depending on density of the board and on the type, site, and depth of the perforations. An average conductivity k value is <}..' * The U. 8. Department'of Commerce. Simplified Practice Breommendatim !a Tkrrmal Conductance Fodort Jar Prt/omed Abort-Deck RooJ Insulation, No. R 237-95, recognise* the specification erf roof insulation on the basis of the C value* stows. Roof insulation is made in thicknesses to meet these value*. Therefore, thick' ness supplied by different manufacturers may vary depending on the conductivity k value of the particular material. - c 102 CHAPTER 9 1959 Guide Table 5 .... Coefficients of Transmission (l/) of Frame Wolk* These coeffideari ore exprenod in Bfo per (hour) (fuare foot) (fofcrWiert degree difference in temperature between Ae tar oo the two itdet), and are bated on an outride wind vefodfy of 15 mph Exasapie--WaiJ 0 4 fxoopfe of Substitution Resistance* used are given below in this table or in Table 5 or 4 Construction Resistance (R) 1. Outside surface (15 mph wind).......................... 0.17 2. Siding, wood, K in. x 8 in. lapped (av. i2).... O.SS 3. Building paper......................................................... 0.06 4. Wood sheatniug (*H* in.).................................. 0-M 5. Air space*.................................................................. 0.97 6. Gypsum lath in.)............................................. O.SS '7. Piaster (sand agg.) (^ in).................................. 0.09 8. Inside surface (still air)....................................... 0.68 Total resistance....................................................... 4-18 U - l/R 1/4 Jt -............................................ 0.24 See value 0.24 in boldface type in table below. Resistances used are given below in this table or in Table S or 4 Replace items 3 and 4 with insul. bd. sheathing (*^2 in.) and items 6 and 7 with gypsum wall board (H Is-) Total resistance.......................................................... 4-IS Deduct 3. Building Paper...................... 0.06 *4. Wood sheathing (*M* in-)-. 0.98 6. Gypsum lath (J4 in.).......... O.SS 7. Plaster (sand agg.) (& in).. 0.09 1.46 Difference...................................................................... S.67 Add 4. Insul. bd. sheathing (*Ms to-) - - 8.06 y jGypsum bd. (J4 in.)........................ 0.46 8.61 Total resistance...................................... '................... 6.18 [/=!/- 1/5.18 -................................................ 0.19 To Adjust U Vuhtes for Construction with Added tnsutotion between Frontnp Members, See Tebio 16. . Type of Sheathing* Exterior* Inferior Finish Hone, GypBuild- )4 in. Insole lion Wood. Bo y- fa1- Shea) ond Bofld- mg Paper H in. * Resistance j--* 0.06 0.45 0.39: 1.04 1.32 2.06 ft Av. Materia) U 8 A U 0' ------- BC U 0 U0 F Drop--(1 in. x 8 Wood shingles in.-) 0.78 0.81 0.86* Gypsum lath @4 in.) and )4 in. pips. (It- wt. Gypsum lath (% in.) and )4 in. plas. (sand agg.)............................'................................................... Metal lath and Ye in. plas. (It. wt. agg.). . Metal lath and Ye in. plas. (sand agg.)......... 0.57 O.SS 0.33 0.64 0.30 0.41 0.32 0.47 0.31 0.IS 0.35 0.47 0.29 0.27 0.28 0.2S 0.31 0.48 0.30 0.27 0.29 0.28 0.31 0.87 0.94 Insul. bd. 0 in.).................................................. 1-43 0.24 Insul. bd. lath 04 in ) and )4 in. plas. (sand agg.)................................................................................. 1.58 0.24 0.22 0.22 0.22 0.22 Face-brick veneer' 0-44 Plywood <$i in.) 0.47 .0.81 0.33 0.9i 0.27 Wood lath and )4 in- pl&s. (sand agg.)........ 0.40 0.32 Gvpsum bd. ($4 in.)........................................... Gypsum lath & in.) and V4 in- pl&$- (it. wt. Gypsum lath (% in.) and in. plas. (sand agg.)....................... ;....................................................... _ 0.35 0.6. OM 0.73 0.37 0.33 0.36 0.29 0.25 0.28 0.66 0.33 0.30 0.32 0.30 0.25 0.29 0.58 0.33 0.30 0.32 0.47 0.35 0.31 0.32 Metal lath and Ye in. plas. (sand agg.)......... 0.1S 0.40 0.35 0.36 Insul. bd. 04 in.).................................................. Insul. bd. lath 04 in.) and Y> in. plas. (sand Wood lath and >4 in- plas. (sand agg.)......... 1.41 1.51 0.3. 0.9. 0.4C 0.26 0.26 0.38 0.30 0.36 0.24 0.23 0.33 0.27 0.32 0.24 0.24 0.33 0.28 0.32 0.36 0.25 0.24 0.26 0.19 0.19 0.25 0.22 0.24 0.42 0.27 0.25 0.27 0.26 0.29 0.21 0.21 0.27 0.23 0.27 0.33 0.27 0.23 0.20 0.22 0.24 0.18 0.16 0.18 0.23 0.20 0.2( 0.18 0.23 0.19 0.38 0.30 0.25 0.21 0.2t 0.20 0.25 0.25 0.21 0.27 0.22 0.2( 0.17 0. H 0.17 0.26 0.21 0.22 0.19 0.25 0.21 Heat Transmission Coefficients of Building Materials Table 5 .... Coefficients of Transmission (l/) of Frame Walls* (Concluded) Type of Sheathing* 103 Number Exterior1 Material s Av. ft Inferior Fistish . Materia) None, Bead- GrP- p,v Wood. *W1D ' wrod ' ta- Insulation Boord Sheathing >4 Hu ?l0Hu mg Paper H . fteriftoace j--* 0.06 0.45 0.3? U UU ft . AB c 1.04 1.32 2.06 U UU 0F Wood shingles over * insul.: backer bd. (Ji in.) 1.40 Asphalt insul. sid- mg 1.46 None.......................................................................... Gypsum bd. (% in.)............................................ Gypsum lath (g in.) and )4 in. plas. (It. wt. agg.)....................................................................... Gvpsum lath (Jfi in.) and >4 in- plas. (sand 1.48* Metal latb and Ye in. plas. (It. wt. agg.).. Metal lath and Ye in. plas. (sand agg.)........ Insul. bd. (M in.).................................................. Insul. bd. lath Os in.) and )4 in. plas. (sand agg-)- -................................................................. 0.43 0.82 0.28 0.64 0.25 0.41 0.27 0.47 0.27 0.18 0.29 1-48 0.21 1.58 0.21 0.37 0.38 0.25 0.25 0.23- 0.23 0.24 0.25 0.24 0.24 0-26 0.27 0.20 0.20 0.19 0.19 0.30 0.22 0.20 0.21 0.21 0.23 0.18 0.17 0.28 0.23 23 0.2C 0.1S 24 0.19 0.17 25 0.20 0.18 26 0.20 0.17 27 0.21 0.18 28 0.17 29 0.16 0.15 30 Asbestos-cement siding Stucco* 1 in. Asphalt roll siding PIvwood in.) Wood panels (J$ in.)............................................ Wood lath and )4 in. plas. (sand agg.)........ -- None..................................................................................... Gypsum bd. ($$ in.)................................................... Gypsum lath 04 in.) and H in. plas. (It. wt. Gypsum lath (% in.) and *4 in. plas. (sand 0.S1 0.28 0.94 0.24 0.40 0.27 -- 0.91 o.se 0.42 0.84 0.37 0.41 0.40 0.81 0.80 0.15 0.19* Metal lath and Ye in. plas. (It. wt. agg.) Metal lath and Ye in. plas. (sand astr.l........ Insul. bd. 04 in.)..........................................' Insul. bd. lath 04 in.) and )4 in. plas. (sand agg.)....................................................................... 0.47 0.39 0.13 0.45 1.4S 0.29 1.58 .0.28 0.25 0.22 0.24 0.67 0.36 0.32 0.35 0.34 0.39 0.26 0.25 0-25 0.22 0.25 0.70 0.37 0.33 0.36 0.35 0.40 0.26 0.26 0.22 0.19 0.21 0.48 0.30 0.27 0.29 0.28 0.31 0.22 0.22 0.20 0. IS 31 0.18 0.16 32 0.20 0.18 33 0.42 0.32 34 0.27 0.23 35 0.25 36 0.27 0.22 37 0.26 0.22 38 0.29 0.24 39 0.21 0.18 to 0.21 0.18 41 Plywood 04 in.).................................................... o.st 0.42 0.36 0.37 Wood panels iYe in.)............................................ 0.94 0.33 0.29 0.30 Wood lath and )4 in. plas. (sand agg.)........ 0.40 0.40 0.35 0.36 0.30 0.25 0.29 0.27 0.23 42 0.23 0.20 43 0.27 0.22 44 * See text section Cskiilstim Ovenll Coefficient! for bub of c&lculxtians. ' * To xdjust V vnloee for the effect of edited jimiiei-- between framing members, eee Table IS. * Note that although wveral types of exterior finish may be grouped became they hare approximately the --thermal resistance value, it is not implied that all types may be suitable for application over all typee of sheathing bated. ' * Average resistance of items listed. This average was used in computation of U values shown. - * Building paper is not included except where noted. '. 1 Small air space between building paper and brick veneer neglected. * Where stucw b applied over insulating board or gyp-rum sheathing, building paper b generally required, but the change in U vmlim b negligible. -b Solution: In Fig. 5 the following paths of heat flow from plane A to plane F will be noted: 1. From A to B: One path through 3 in. of concrete. 2. From B to C: Two paths, (a) through 1 in. of tie rod, and (6) through l.in. of concrete. 3. From C to D: Two paths, (a) through 2)4 in. of tie rod, and (b) through 2)4 in. of insulation. -- 4. From D to B: Two paths, (a) through 1 in. of tie rod, and (6) through 1 ini of concrete. 5. From E to F: One path through 3 in. of concrete. It will be noted that items 2 and 4 are paths of similar flow, and* could be treated as one. If equilibrium or steady-state heat transfer is assumed, there will exist a temperature dif ference between the metal tie rod and the concrete, and also between the metal tie rod and the insulating material. The rate of heat transfer between these materials is dependent upon their conductivity values and the temperature difference. As the conductivity of the metal tie rods is considerably higher than that of the concrete or insulating material, it cannot be assumed that the same rate of heat transfer takes place for all parallel paths. Likewise, an appreciable error would be made by assuming that no heat transfer takes place between the metal lie rod and the surrounding materials. Although the pat . tern of the isotherms is unknown, the following method of cal culation does partially take into account the heat flow between the metal tie rods and ite bounding materials. Parallel Flow. The conductances through the areas of parallel heat flow may be determined as follows: l.The area of each )4-ro. diameter tic rod is 0.00034 sq ft, and as the tie rods are spaced 9 in. vertically, and 12 in. hori- 104 CHAPTER 9 1959 Guide Table 6 .... Coefficients of Transmission (U) of Solid Masonry Walls* . CMlGdcnti or* .xpraowf in Bin pnr (Boar) [iquam foal) (FdluaafiaH deem difference in leeiperninre between the nir on the ten ddei), and are band nn a* niMde mi>d velocity sf IS sspts Example--Waff G 2 ExompJ* of Substitution ^'^CPtfn 1 1/I/ll 1 *34S' . Resistances used are given below in this Resistances used are given below in tabic or in Table 3 or 4 this table or in Table 3 or 4 Construction Resistance (fi) Assume plain wall--00 furring or plaster. 1. Outside surface (15 mph wind)........................... 0.17 Total resistance.......................................................... 547 2. Face brick (4 in.)...................................... D0e.d44uct 4. Airspace....................................... 0.97 3. Common brick (4 in.)............................................. 0.80 5. Gypsum lath 04 in.)................0.33 4. Airspace11................................................................... 0.97 6. Plas. (sand agg.) 04 in).......... 0.09 1.38 5- Gypsum lath 04 in.). ...................................... 0.33 6. Pfas. (sand agg.) 0i'm.)......................................... 0.09 Total resistance.......................................................... 3.09 7. Inside surface (stiff air)......................................... 0.68 U ~ 1/fi - 1/3.09 _................................................ 0.48 Total resistance...................................................... 3.47 V - 1/fi - 1/547 -.................................... ... 0.29 See value 0.29 in boldface type in table below. To Adjust U Vatuttx for Construction with Added Insulation between Furring Strip*, See Table 16 Interior Fdajb - Ejtferior Construction* None . 1 Resistance ^--> Pics. % In. 00 WaU Metal Loth end In. Plas. on Furring (Sand 090.) 0J? (Li. wt. OfloJ 0.39 (Sand age-) 0J3 (Lt. wt. agg.) 0.47 ' Gypsum lath 04 bv) and Plas. on Furring InssL Bd. Loth (M Bvl and H ** Plas. on Furring Wood Lath anc H in. Has. No plas. (Sand (Lt. wt No aggj aggj plat (Sand agg.) Number (Sand aggj 0.32 0.41 0j&4 1.43 1.52 0.40 Material Brick (face and common)*5 (6 in-.) (8 in.) . (12 in.) (16 in.) ' Brick (common only) (8 in.) . (12 in.). . (16 in.) . . Stone (lime and sand) (8 in.) (12 in.) (16 in.) (24) in. Hollow clay tile (8 in.) (10 in.) (12 in.) Uu U U U U .A B C O E FGH 1 JK 0.61 1.34 3.04 3.84 0.68 0.48 0.35 0.27 1.60 8.40 3.80 0.41 0.31 0.25 0.64 0.96 1.38 1.98 0.67 0.55 0.47 0.36 1.85 8.88 8.60 0.36 0.33 0.30 0.64 0.45 0.33 0.26 0.39 0.30 0.24 0.63 0.52 0.45 0.35 0.36 0.31 0.29 0.54 0.41 0.30 0.25 0.35 0.27 0.23 0.53 0.45 0.40 0.32 0.32 0.29 0.27 0.39 0.31 0.25 0.21* 0.34 0.28 0.23 0.19 0.28 0.23 0.19 0-26 0.21 0.18 0.39 0.34 0.31 0.26 0.34 031 028 0.24 0.26 0.24 0.22 0-24 0-22 0.21 0.36 0.30 0.24 0.20 0.27 0.22 0.19 0.36 0.32 0.29 0.25 0.25 0.23 0.22 0.35 0.89 0.23 0.20 0.26 0.22 0.18 0.35 0.31 0.28 0.24 0.25 0.22 0.21 0.33 0.27 0.22 0.19 0.26 0.22 0.19 0.16 0.25 0.21 0.18 0.21 0.18 0.16 0.32 0.29 0.27 0.23 0.26 0.24 0.22 0.19 0.23 . 0.20 0.21 0.18 0.20 0.17 0.25 0.22 0.19 0.16 0.20 0.17 6.15 0.25 0.23 0.22 0.19 0.19 0.18 0.17 0.35 0.29 0.23 0.20 0.26 0.22 0.18 0.35 0.31 0.29 0.24 0.25 0.23 0.21. 2 4 6 6 7 9 10 11 18 13 14 Poured concrete 30 lb per cut ft ' (4 m.) (6 in.) . (8 in.) (10 in.) 80 lb per cut ft (6i). (8 in.)' (10 in.) (12 in.) 140 lb per cut ft (6 in.) (Sin. (10 in.) (12.in.) . 4M 0.19 0.19 6.66 0.13 0.13 8.88 0.10 0.10 11.10 0.08 ' 0.08 ' 8.40 0.31 0:30 3.80 0:25 0.24 4.00 0.21 0.20 4.80 0.18 0.17 0.48 0.64 0.80 0.96 0.75 0.67 0.61 0.55 0.69 0.63 0.57 0.52 0.18 0.13 0.10 0.08 0.27 0.23 0.19 0.17 0.58 0.53 0.49 0.45 0.16 0.12 0.09 0.08 6.23 0.19 0.17 0.15 0.41 0.39 0.36 0.34 0.15 Oil 0.09 0.07 0.21 0.18 0.16 0.14 0.36 0.34 0.32 0.31 0.15 0.11 0.09 0.08 0.22 0.19 0.16 0.14 0.38 0.36 0.34 0.32 0.15 0.11 0.09 0.08 0.22 0:18 0.16 0.14 0.37 0.35 0.33 0.31 0.14 0.11 0.09 0.07 0.21 0.18 0.15 0-14 0.34 0.32 0.31 0.29 6.13 0.10 0.06 0.07- 0.13 0.10 0.08 0.07 0.18 0.16 0.14 0.12 0.17 0.15 . 0.14 0.12 0.15. 0.11 0.09 0.08 '- 0.22 0:18 0.16 0.14- . 15 . 16 17 18 19 20 21 22 0.27 0.26 0.25 0.24 0.26 0.2S 0.24 0.23 0.37 0.35 0.33 0.31 . 23 24 25 26 Heat Transmission Coefficients of Building Materials Table 6------Coefficients of Transmission (U) of Solid Masonry Walls (Concluded) 105 Exterior Construction* None Resistance |--* Material . Concrete block (gravel agg.) (8 in.) (Cinder see.) (8 in.) (Lt. wt. agg.) (8 ro.) U A 1.11 0.52 1.78 1.89 8.00 0.39 0.36 0.35 Plas. 5^ in. on Waff Metal Lath and % In. Plas. on Furring Gypsum Lath 04 i"-) and 14 in. Plas. on Furring brad. Bd. lath Wood [}4 in.) and )4 in* Loth ond Hoi. on Furring H In. Hat. (Sand agg.) OJI (Lt wt. ogg.) 0.39 (Sand ogg.) 0J3 (It. wt. aggj 0.47 No plas. 0.32 UUU UU B CDE F (Sand agg.) 0.41 (Lt. wt. ogg.) 0.44 No plas. 1.43 U U It GH I (Sand ogg.) 1.52 (Sand aggj 0.40 UU JK 0.48 0.45 0.37 0.35 0.34 0.31 0.43 0.40 0.34 0.32 0.31 0.28 0.33 0.31 027 0.26 0.28 024 0.29 0.28 0.25 0.24 0.23 0.22 0.31 0.29 0.28 0.25 0.24 0.23 0.30 0.28 0.25 0.24 0.24 0.22 0.28 0.27 0.23 0.22 0.21 0.22 0.19 0.18 0.22 0.19 0.18 0.29 0.24 0.22 To edjast U value* far the effect of added iraulstioo between framing member*, eee Table Ifl. dIi^f*?f^trUCMlral "*PPlied tti"ext*rior'theadditioaa! re*ita,ioe value of 0.10 would hare* oegligiblo effect oo the U value Bock, S in. (SM in. actual) is assumed to have no backing. Walla 8.12 and 16 io. have t in. of face brick and balance of common brick. tontally, there will be 0.00034 X % - 0.00045 sq ft of tie rod to each square foot of wall area. Thea from plane B to plane C the conductance Ct is .' ,, 0.00045 400 0.99955 12 c`"-i5-xn + -urxr5 - 0.180 + 11.994 - 12.174 .. 2. For tie rod and insulation from plane C to'plane D the conductance C* is C = 0 00045 v 400 0.99955 0.30 * 1.0 X 2b + 1.0 X 2.5 The hot box test value, from University of Minnesota, for this wall, corrected fora 15mph wind velocity, was U = 0.150 Btu per (hr) (sq ft) (F deg). The error between the calculated and test values would be 0.150 - 0.149 ------ 0150------ X 100 * 0.67 percent. If the effect of the tie rods were omitted from the calcula tions, the overall U value would be 0.103. Although the per centage of area occupied by the tie rods per square foot of wall area is 0.00045/1.0 X 100 = 0.045 percent, the error between the calculated and test values would be = 0.072 + 0.120 - 0.192 3. For tie rod and concrete from plane D to plane B the con ductance C* is - /> _ -00Q45 400 * 1.0 X 1.0 + l.o 1.0 = 0.180 + 11.994 - 12.174 . Series Flaw. After the conductance values have been deter mined, the total resistance and U value can be determined as follows; ' l , Z% , 1 . 1 1 St 1 ' ,: fi + r4,+' ^C+, c. + c, + +/. Rr M 11.655 * 12.0 + 12.174 + 0.192 1 12.174 12.0 W) Rr = 0.606 + 0.250 + 0.0822 + 5.208 + 0.0822 + 0.250 + 0.167 = 6.727 11 " Rr " " ?49 Btu per (hr) (sq ft) (F deg). ------ -------- X 100 = 31 percent. Values Used in Calculation of U Value Tables Tables 5 through 15 are based on values given in Table 4. The following conditions have been used: Equilibrium or steady-state heat transfer, eliminating effects of heat capacity. ' Surrounding surfaces at ambient air temperatures. Exterior wind velocity of 15 mph for winter and 7.5 raph for summer. Surface emissivityof ordinary building materials = 0.90. Stud space in frame construction not insulated. (See Table 16 for method of correcting for added insulation.) In construction involving air spaces the U values shown are calculated for areas between framing. See Fig. 6 in section Correction for Framing if an allowance is to be merit. for this effect. Air space resistance values used are those shown in Table 4 under Air Spaces. Air spaces are ? in. or more in width. ' 1 ^j*a^ODS conductivity with mean temperature is neg- Corrections for framing to be made on basis of parallel heat , (Continued on p. /at) 106 CHAPTER 9 1959 Guide >^^8^ Table 7.... Coefficients of Transmission (U) of Masonry Walls* expressed a Btoper (hoar) (squarw'foot) (FdnaM ttegrw* dlmm in teaperxiture between the air on the two tided. and ore boxed on on outside wtod velocity of 15 mpfa Example--Well G 1 Resistances used are given below in this table or in Table 3 or 4 Construction Resistance (ft) i. Outside surface (15 mph wind)........................... 0.17 2. Face brick (4 in.) (av. ft.)...................................0.59 Example of Substitution Resistances used are given below in ' this table or in Table 3 or 4 Replace items 6 and 7 with wood panels ($6 in.) and vapor barrier applied over furring strips 1L4* Concrete block (cinderagg.) (4 in.)...................... 1.11 Un 5. Airspace*............................................................... 0.97 Jrfl 6. Gypsum lath (96 in.)...................................... .. - 0.55 /! 7. Plas. (sand agg.) (H in)...................................... 12345*78 8- Inside surface (still air).......................................0.68 Total resistance...................................................... 3.85 U = 1/ft = 1/3.85 =............................................0.26 See value 0.26 in boldface type in table below. Deduct 6'. Gypsum lath (96 in.)........... 0.55 7. Plas. (sand agg.) 04 in)-- 0.09 0.41 Difference...................................................................... 8.42 Add 6. Vapor barrier.................................... 0.06 7. Wood panel (96 in.)........................ 0.94 1.00 Total resistance.......................................................... 4-4* V - l/R - l/(4 -................ 0.Z1 Face brick 4 in. Stone 0-U 4 in. 0.32 Precast concrete (sand agg.) 4 in. 0.32 6 in. 0.46l Interior Ftrudi Backing Mono Plas. 96 tn. on >Aetal lath and 96 ai Plas. on Furrmg U. wt (Sand U. wt. aggj aggj agg.) agg.) 144 and V, Mm M. Sirring No [Sand Lt. wt. plas. aggj agg.) Resistance j--* 0JT 0.59 0J3 . 0.47 0.32 0.41 0.64 Concrete block (Cinder agg.) (12 in.) (Lt. wt. agg.) (12 in.) (Sand agg.) (12 in.) U U U U U U U U A B C D E F G H 1.11 0.41 0.39 1.72 0.33 0.32 1.89 0.31 0.30 0.35 0.29 0.28 0.28 0.24 0.23 0.26 0.22 0-21 0.27 0.23 0.22 0.26 0.23 0.22 0.25 0.21 0.21 0.35 0.34 2.00 0.30 0.29 2.27 0.28 0.27 0.31 0.27 0.25 0.25 0.23 0.21 0.23 0.21 0.20 0.24 0.22 0.20 0.24 0.21 0.20 0-22 0.20 0.19 0.49 0.46 0.41 0.39 1.28 0.38 0.37 0.41 0.35 0733 0.32 0.28 0.27 0.29 0.26 0.25 0.30 0.27 0.26 0.29 0.26 0.25 0.27 0.25 0.24 in. Plas. on Furring Na [Sand pla*. agg.) Wood lath Plas. (Send agg.) 1.43 1.52 0.40 UU l J U K___ 0.21 0.20 0.28 0.18 0.18 0.17 0.19 0.19 0.24 0.17 0.17 0.22 0.22 0.29 0.21 0.20 Hollow clay tile (12 in.) Concrete (Sand agg.) (8 in.) 0.39 0.31 0.30 2.60 0.2 0.25 0.35 0.28 0.24 0.28 0.23 0.20 0.26 0.22 0.19 0.27 0.22 0.19 0.26 0.22 0.19 0.25 0.21 0.18 0.21 0.18 0.16 0.20 0.26 0.32 0.60 0.66 0.55 0.52 0.64 0.51 0.48 0.49 0.45 0.42 0.38 0.34 0.32 0.32 0.31 0.29 0.34 0-32 0.31 0.33' 0.31 0.31 0.29 0.30 0.28 0.25 0.24 0.23 0-24 0.33 0.31 Common brick 4 in. < Precast concrete (sand agg.) Concrete block (Cinder agg.) (12 in.) (Lt. wt. agg.) (12 in.) (Sand agg.) (12 in.) 0.36 0.35 0 7? 0.29 1.89 0.28 0.27 0.32 0.30 2.00 0.21 0.26 2.27 0.25 0-25 0.42 040 0.36 0.35 1.24 0.34 0.33 0.32 0.26 0.25 0.28 0.25 0.23 0.36 0.32 0.30 0.26 0.22 0.21 0.23 0.21 0.20 0.29 0.28 0.25 0.24 0.21 0.20 0.22 0-20 0.19 0.26 0.24 0.23 0.25 0.21 0.21 0.22 0.20 0.19 0.27 0.25 0.24 0.24 0.21 0.20 0.22 0.20 0.19 0.27 0.24 0.23 0.23 0.20 0.19 0.21 0.19 0.18 0.25 0.23 0.22 0.19 0.17 0.17 0.18 0.16 0.16 0.21 0.19 0.19 0.19 0.17 0.18 0.16 0.21 0.18 0.24 0-22 0.27 Hollow clay tile (12 in.) Concrete (Sand agg.) (8 in.) 0 36 0.35 0.25 0.28 2.61 0.24 0.23 0.51 0.5C 0.48 0.4' 0.44 O.64 0.42 0.41 0.32 0.26 0.26 0.22 0.22 0.19 0.42 0.32 0.39 0.31 0.37 0.29 * See text r-*1"" CUeuUiio* Overall CoeSdenta for bed* of calculation. b To adjust U values for tbe effect of added baolatioa between framing member*, aee Table 14. 0.24 0.20 0.18 0.29 0.28 0.27 0.25 0.21 0.18 0.30 0.29 0.28 0.24 0.20 0.18 0.30 0.28 0.27 0.23 0.19 0.17 0.28 0.27 0.26 0.19 0.17 0.15 0.23 0.21 0.19 0-17 0.22 0.24 0.30 Heat Transmission Coefficients of Building Materials 107 Table 8 .... Coefficients of Transmission (l/) of Masonry Cavity Walls* Coefficients are expressed m Bio per (hour) (square foot) (Fahrenheit degree difference in temperature between the air on the two sides), and are based on an ovtside wind velocity of 15 atph Example--Wcfl H 6 Cxample of Substitution l2 345*7 a Resistance* used are given below in this table or in Table 3 or 4 Construction Resistance (ft) 1. Outside surface (15 mph wind)......................... 0.17 2. Common brick (4 in.) (av. ft.)........................... 0.76 3. Airspace*.................................................................. 0.97 4. Concrete block (grave! agg.)(4 in.).................. 0.71 5. Air space*.....................................................................0.97 6. Gypsum lath (96 io.)............................................... 0.33 7. Plas. (It. wt. agg.) Q4 in-)................................... 8.32 8. Inside surface (still air)....................................... 0.68 Total resistance...................................................... 4.00 U * 1/ft = 1/4.90 *=.............................................. 0.20 See value 0.20 in boldface type in table below. Resistances used are given below in this table or in Table 3 or 4 Replace item 4 with 8 in. concrete block and items 6 and 7 witb % in. plas. (sand agg.) applied directly to concrete block. Total resistance........................................................... 4-80 Deduct 4. Concrete block (gravel agg.) 4 in................................................. 0.7/ 5. Air space....................................... 0.97 6. Gypsumlath ($6 in.).................. 0.32 7. Plas. (It. wt. agg.) ($4 in.)___ 0.32 2.32 Difference....................................................................... 2.68 Add 4. Concrete block (gravel agg.) 8 in............................... 1.12 7. Plas. (sand agg.) (96 in)................ 0.11 1.22 Total resistance -............................................... 3 80 t/ - 1/ft = 1/5.80...................................................... 0.26 To Adjust U Value* for Construction with Added Insolation' between Inner and Outer Iters or between Furring Strips, See Table Id Number Table 10. 108 CHAPTER 9 1959 Guide Table 9 .... Coefficients of Transmission (l/) of Frame Partitions of Interior Walls4 Coefficients are expressed m Bhi per (floor) (Kjucre foot) (Fahrenheit degree difference m Temperature between the air on the two rides), and ore bated on itiff sir (no wind) condition* on both ddet Example--Wail fi ) . . Example at Substitution Resistances used are given below in this Resistances used are given below in this n. table or in Table 3 or 4 table or in Table 3 or 4 || Construction Resistance (ft) Replace item 2 with wood fiber hardboard 04 >Q) II 1. Surface (still air)..................................................... 0.68 Total resistance.......................................................... 3.97 1 || 2. Gypsum bd. 04 in-)............................................... 0-38 Deduct 2. Gypsum wall board 04 in.)............... 0.33 I ||--1 3. Air 6paceb................................................................... 0.97 |-- 1 4. Gypsum wall board ($ in.)................................. 0.33 Difference.................................................................... 8.66 I I 1 5. Surface (still air)..................................................... 0.68 Add 2. Hardboard (J in.)................................... 0.18 tjj Total resistance........ ............................................. 8.97 Total resistance.................... .....................................8.83 1/ft = 1/3.97................................................ 0.34 U = 1/ft - 1//-83 "..........;............. .. s........ .. 0.35 See value 0-34 in boldface type in table below. To Adjatt U Valuer tor Construction with Added Insulation between Members, See Table 16 Type of Interior Knidi Single Partition (Fusdi on Only One Side of Studs) Double Partition (Ftm'di on Both Sides of Studi) Gypsum bd. (H in.)....................................................-. . Gypsum lath (% in.) and )4 in. pias. (It. wt. agg.) Gypsum lath (J in.) and )4 in. pias. (sand agg-). Meta! lath and % in. pias. (It. wt. agg.).................... - Meta! lath and $4 in. plas. (sand agg.)....................... Insul. bd. 04 in-)._____ _ - -........................................ . Insol. bd. lath 04 in.) and H pl"- (sand agg.)----- Plywood: 04 in.)..'............................................................. - (H in-)....... -............................................... 04 in.)........ . . ................................................ Wood panels 04 in.).......................................................... Wood-lath and \4 in. plas. (sand agg.)........................ Sheet-metal panels.............................................................. Glass and glass blocks.................................................... - * ri irrrl mrtinri '~*1m1iitiTii 'Vnnll trn beria t4 teVco^artama. b To Adjust U Tsloee for the effect of Added insalAtkm between (nuniag members, see Table 16. 0.38 0.64 OM 0.47 0.1s 1.4s . 1.63 0.S1 0.47 0.6S 0.94 0.40 0.60 0.60 0.56 ' 0.65 0.67 0.36 0.35 0.60 0.55 0.50 0.43 0.57 0.74 See Table 21 0.34 0.28 0.32 0.31 0.39 0.19 0.19 0.34 0.31 0.28 0.24 0.32 0.43 flow through 2 x 4 in. (nominal) studs, 16 in. on centers, the framing covering 15 percent of wall area, as shown in Fig. 6. Thermal resistance for gypsum board and insulating board apply equally to plain material and to those which may be decorated at the factory or on the job. ., In order to condense the tables an average resistance value (Av.ft) has been used in some tables for types of materials hav ing approximately the same thermal resistance values. The dif ference between the average value and the exact value for any given material usually causes no significant change in the re sulting U value. ' "' Actual thicknesses of lumber assumed to be as follows: Nominal Actual Nominal Actual 1 in. (S-2-S)___ *Hx in. 1H in. (S-2-S)___ . 1He in. 2 in. (S-2-S).... 1% in2)4 in. (S-2-S)... ...2)4 in. 3 in. (S-2-8).............. 25in. 4 in. (S-2-S).............. .. Z% in. Finish flooring, (maple or oak) ... .. H in- It should be noted that the effects of poor workmanship in construction and installation have an increasingly greater percentage effect on heat transmission as the coefficient be comes numerically smaller. Failure to meet design estimates may be caused by lack of proper attention to exact compliance with specifications. A factor of safety may be employed as a precaution when it is judged desirable. .' Insulating Materials ' In order to determine the benefit derived from the addition of insulating materials to a given construction, the overall coefficient of heat transmission U< of the insulated construc tion may be compared with the corresponding coefficient U without insulation. Table 16 (Part A to Part E) and Fig. 6 may be used for determining the coefficients of transmission of constructions with any combination of fibrous, bulk, or mass insulation and air spaces of various effective emissivities. Example 3: Find the coefficient of transmission of a frame wall consisting of H * 8-in. bevel lap wood siding, building pa- (CatiMeei en f. Hit Heat Transmission Coefficients of Building Materials 109 Table 10 .... Coefficients of Transmission (U) of Masonry Partitions4 Coefficient! an expressed in Btv per (boar) (square foot) (Fahrenheit degree difference hi temperature between the air on the two odes), and ore bosed on riitt oil (no wind) conditions on both ride* Example--Wed C 2 Example of Substitution Resistances used are given below in this table or in Table S or 4 Construction Resistance (A) 1. Inside surface (still air).............. '.......................0.68 2. Plus. (It. wt. agg.) % in....................................... 0.S9 3. Cement block (cinder agg.) (4 in.).................. l.tl 4. Pias. (It. wt. agg.) % in:..................................... 0.39 5. Inside surface (stiff air)...................................... 0.68 Resistances used are given below in this table or in Table 3 or 4 Replace item 3 with gypsum tile (4 in.) Total resistance.......................................................... 3.45 Deduct 3. Cement block (cinder agg.) (4 in.).. 1.11 Difference...................................................................... gJ4 Add 3. Gypsum tile (4 in.).................................... 1.67 Total resistance.........................-............................ 3.36 Total resistance .. V ** \/R -- i/3.36 ........................................ 0.31 U ~ 1/R = 1/3.8/ = See value 0.31 in boldface type in table below. . 3.81 0.26 Type of Partition Hone - Resistance ^--------- - U. Hollow concrete block (Cinder agg.) (5 !")...................................................................... (8 in.)...................................................................... (12 m.)...................................................................... 0.86 l.li 1.73 1.89 (Lt. wt. agg.) -- P !")...................................................................... (4 in.)........................................................ ............. (*!>................................................................ (12 in.)................................................................... 1.37 1.60 3.00 3.37 (Gravel agg.) ' (!")...................................................................... (12 in.).................................................................... 1.11 1.38 Hollow clay tile ' (3 in.)....................................................................... (6 ID.)........................................................................ (8 in.)........................................................................ 0.80 1.11 1.63 1.86 Hollow gypsum tile ' 8 !").......................................... ' ......................... (4 in.)................................................................ 1.36 1.67 Solid plaster walls Gypsum lath 04 in.) and pias. % in. each side - (Lt. wt. agg.)................................... ................ (Sand agg.)......................................................... 1.39 0.7/ 1 in. each side (Lt. wt. agg.)................................... '................ (Sand agg.)......................................................... Metal lath and pias.* 2 in. total thickness (Lt. wt: agg.)..................................................... (Sand aggi) . ................................................ 2)4 in. total thickness (Lt. wt. agg.)................................. ................... (Sand aggT)......................................................... /.73 0.81 1.38 0.36 1.60 0.46 Glass and glass blocks A 0.45 0.40 0.32 0.31 0.38 0.35 0.30 M).2S 0.40 0.38 0.46 0.40 0.35 0.31 0.37 0.33 0.36 0.48 0.32 0.46 0.38 0.58 0.34 0.55 Surface Finis Pias. (IL wt. OB9-) M "* Pias. (sand oggj % in* One side Two sides One side Two sides <U? 0.76 ' 0.11 0J2 'u -U. c U 0 U 6 0.38 0.35 0.29 0.27 0.33 0.31 0.27 0.25 0.35 0.33 0.39 0.35 0.31 0.28 0-32 0.29 0.33 0.31 0.26 0.25 0.43 0.39 0.31 0.30 0.30 0.27 0.24 0.23 0.36 0134 0.29 0.27 0.31 0.29 0.39 0.36 0.34 0.31 0.27 0.25 0.44 0.39 0.33 0.30 0.29 0.26 0.35 0.32 0.41 0.37 0.30 0.29 0.35 0.32 0.28 0.26 0.37 0.35 0.42 0.37 0.32 0.29 0.34 0.31 .__ __ __ __ ---- ---- __ __ __ __ ---- - --- __ __ __ ------ __ -- See Table 21 __ -- __ .-- __ " Number 1 8 3 4 6 6 7 8 9 10 11 18 13 14 . 16 16 17 18 19 20 81 22 83 84 I 110 CHAPTER 9 1959 Guide Table 11 .... Coefficients of Transmission (U) of Frame Construction Ceilings and Boors* Cosf&cfaah or* expretsed fa BJv per Utoor) (tqvara foot) (Fahrenheit degree difference between the eir on (tie two ode*) and ere bated on did air (no wind) condition* on boffi tide* Ejtampfe--Floor K 5 fioopie of Substitution Resistances used are given below in this table or tn Table 8 or 4 ` Heated room above unheated space Construction Resistant*(*) (Heat flow down) 1. Top surface (still air)..................................... 0.98 2. Linoleum or tile (av. R)................................ 0.05 3. Felt.................................................................... . 0.06 4. Plywood (M in.)............................................ . 0.78 5. Wood subfloor (*Ma*n-)............................... . 0.98 6. Air space*' (7M in.)........................................ . 1.85 7. MetaJ lath and % in. plas. (It. wt. agg.).. . O'.47 8. Bottom surface (still air)............................. . 0.98 Total resistance............................................... 5.48 U - l/R = 1/6.48 -..................................... 0.18 See value 0.18 in boldface type in table below. Resistances used are given below in this table or in Table 8 or 4 Assume heated room is below unheated space so heat flow is up Total resistance......................................... Deduct I. Top surface (heat flow down). 0.88 6. Air space (beat flow down)... 1.85 8. Bottom surface (heat flow down)........................................ 0.98 Difference................................................... Add 1. Top surface (beat flow up)........0.6t 6. Air space (beat flow up)............. 0.85 8. Bottom surface (heat now up).. 0.61 Total resistance..-- U ~ l/R - 1/4.41 - 5.48 8.09 8.84 8.07 4.41 0.23 To Adject U Value* tor Construction with Added /natation between Framing Member*, See Table 16 Type of Floor Wood wbfloor inj. felt, ond-- Wood tubfloor (*5^j inj Type of CeICng Redstone* j i * 0.98 ~ i1 6, 1.38 Hardwood floor In.) i 1 s* *e X S3 ii Is 1 Id i --E 6 Z. E dix E 6t a S 60 il | A i xM Z !!8 6 -b-- o I z *i 1 J uE *\* o 4 z c |2 o 1.87 226 0.98 148 1J2 ?47 2.26 u U U U U Uu u U U U U A e C D E F cH 1 i K None................................................................. - - 0.45 0.38 0.34 0.31 0.28 - 0.35 0.31 0.28 0.26 0.24 Gypsum bd. ($4 in.)...................................... 0.88 Gypsum lath 0i in.) and in. plas. (It. 0.64 Ovnsum lath (44 in.) and \4 in. Dias, (sand agg.).......................................................... 0.41 0.65 0.30 0.64 0.27 0.61 0.29 Metal lath and % in. plas. (It. wt. agg.).. 0.47 0.59 0.28 Metal lath and % in. plas. (sand aggJ__ 0.13 0.74 0.31 0.27 0.24 0.26 0.26 0.28 0.24 0.23 0.24 0.23 0.26 0.23 0.21 0.22 0.22 0.24 0.21 0.46 0.23 0.20 0.40 0.21 0.21 0.44 0.22 0.20 0.43 0.22 0.22 0.M 0.24 0.21 0.20 0.21 0.20 0.22 0.20 0.18 0.19 0.19 0.20 0.18 0.17 0.18 0.18 0.19 0.17 0.16 0.17 0.17 0.18 Insul. bd. 04 in.). . .................................... 1.48 0.38 0.22 0.20 0.19 0.18 0-17 0.31 0.18 0.17 0.16 0.15 0.15 Insul. bd. lath 04 in.) and H in. plas. (sand agg.).......................................................... 1.58 0.36 0.22 0.20 0.19 0.18 0.17 0.30 0.18 0.17 0.16 0.15 0.14 1 2 3 6 6 7 04 in.) on gypsum bd. (H in-)................ 1.51* 0.37 0.22 1.19 0.41 0.24 (in.) on gypsum bd. ($i in.)............... 8.10* 0.3C 0.19 04 i-) <>n furring...................................... 1.78 0.33 0.21 Wood lath and \4 in. plas. (sand agg.) 0.40 0.62 0.29 0.20 0.22 0.18 0.19 0.26 0.19 0.20 0.17 0.18 0.24 0.18 0.19 0.16 0.17 0.22 0.17 0.3( 0.18 0.17 0.18 D.3J 0.19 0.18 0.15 0.25 0.16 0.15 0.16 0.28 0.17' 0.16 0.21 0.45 0.22 0.21 0.16 0.17 0.15 0.15 0.19 0.15 0.14 0.15 0.18 0.14 0.13 0.14 0.17 11 12 13 * Gee text aection Overall Coeffidenta tor bad* of calculation*. - b To adjust U values tor the effect of added inaulation between framing member*, aee Table 10. * Includes asphalt, rubber, and plsstm tile (M in.), eeramie tile, or tenasso (I in.). ' * Includes thermal resistance of Jf in. gypeum wall board. Heat Transmission Coefficients of Building Materials 111 per, *%s-in. wood sheathing, studs, gypsum lath, and s&nd aggregate plaster, with 2-in. fibrous insulation between studs. Solution* According to the example calculation in Table 5 a wall of this construction with no insulation between studs has a coefficient U of 0.24. Referring to Table 16, Part A, it will be found that a wall of this value with 2-in. fibrous insulation be tween the studs has a coefficient U of 0.087. tained in one step to reenter the same table through Column I. In thi3 way U values may be obtained for combinations of insulation in the framing space. For combinations of fibrous insulations and air spaces, take account of the fibrous component first and the air space second as illustrated in Example o. This is necessary to assure the ap proximately correct temperature difference across the air space. Attention is called to the necessity of applying the insulat ing material in accordance with the manufacturer's specifica tion. The engineer must evaluate carefully the economic con siderations involved in the selection of an insulating material as adapted to various building constructions. I^ck of proper evaluation, or improper installation may lead to unsatis Examples of the Use of Table 16 Example 8: Find the coefficient of transmission Ui of the frame wall shown as an example at the top of Table 5 when (a) a 2-inch blanket fibrous insulation is added between the studs and in contact with the gypsum lath and when (5) alumi num-foil-backed gypsum lath is added. factory results. Special attention must be given to vapor barriers as outlined in Chapter 10. Moisture from condensa tion or other sources materially reduces the heat-flow resist ance of insulation. Solution; According to Table 5, the U value for this construc tion with no insulation in the air space is 0.24. Referring to Table 16, Part A, for walls, it is found that corresponding to the value 0.24 in Column 1, the coefficient for conditions (a) and (b) are: INSULATED CONSTRUCTIONS--HOW TO USE TABLE 16 (a) In Column 4, find Ui " 0.087. Use 0.09. (b) From Table 3, Section C, the effective emissivity E of aluminum foil is 0.05. In Column 8 find Ui = 0.173. Use 0.17. In Tables 5 through 15, U values are given for many com Example 4 Consider the floor-ceiling construction shown in mon types of building wall, floor, and ceiling constructions. For such of these constructions as contain an air space, the the example at the top of Table 11, insulated with a sheet of aluminum foil, or paper faced on both sides with foil, (effec tive emissivity E of air space * 0-05) placed between the joists tabulated U value is based on the assumption that the air and dividing the air space into two equal spaces. From Table space is empty, and that its surfaces are of ordinary building II, the U value for the uninsulated construction is 0.18 for materials of low thermal reflectivity, such as wood, masonry, plaster, or paper. Considerable benefit in reducing the heat transmission coefficient of a construction can be effected by heat flow down for summer, and 0.22 for heat flow up for win ter. Determine the coefficient Ui for: (a) Heat flowing downward from uncooled room above to cooled space below (a summer condition) and, the application of thermal insulating materials in the air space. (b) Heat flowing upward from heated room below to un Table 16 provides a means of determining, without calcu heated space above (a winter condition). lation, the U value of the between-framing area of such con Solution; - structions with the added insulation installed in the air space. Column 1 of Table 16 refers to the U values of tininsnlatpH constructions as taken from Tables 5 through 15. Columns 2 to 14 of Hie table give corresponding coefficients t/,- for the (o) Use Table 16, Part D, and corresponding to U -- 0.18 in Column 1 find, in Column 11, Ui -- 0.049. Use 0.05. (b) Use Table 16, Part C, and corresponding to U = 0.22 in Column 1 find, in Column 11, Ui -- 0.12. constructions with various insulating applications in the be tween-framing air space, as indicated by the column headings. Table 16 is in 5 parts, (A, B, C, D, and E) corresponding to the type of building element and the direction of heat flow. Each part is based on temperature conditions considered generally appropriate for the case. Any and all U values are based on a series of assumptions as to nominal characteristics. Common variations in condi tions, materials, workmanship, etc., can introduce much greater variations in U values than the variations resulting from the assumed mean temperatures and temperature dif ferences described. From this it is also clear that the use of more than two significant figures in stating a U value is as suming more precision than can possibly exist. Three signifi cant figures are used in Table 16 merely as a means of reducing cumulative errors when the table is used several times to ob "' Special Uses of Table 16 Values of U< for insulating applications or combinations other than those indicated by the headings of Columns 2 to 14 of Table 16 can be ascertained if the table is used appro priately. For instance, going horizontally in the table from Column 2 to Column 3 is equivalent to adding \4 in. of fibrous insulation to the construction. Similarly, going from Column 2 to Column 4 adds 1M in. of fibrous insulation to the con struction. In the same way, going horizontally from Column 8 to Column 11 is equivalent to adding to a construction the Insulating value of one additional highly reflective (E -- 0.05) air space, and going from Column 6 to Column 12 in effect adds two non-reflective (E = 0.82) air spaces to the construc tion, etc. Examples 5 and 6 show the combinational use of Table 16 tain a single result. It should ont be assumed that the figures are accurate, overall, to three significant figures. Also, a re sult taken from Table 16 should always be rounded off to two significant figures. * To use Table 16: 1. Find in Column 1 of the appropriate table the value for U obtained from Tables 5 through 15 for the construction without added insulation. 2. If there is a column which exactly corresponds to the con dition for which you desire the U value, read the answer in this column, opposite the Column 1 value. Interpolate if neces sary. Example 5: Determine the coefficient Ui for the wall of Example 8, with 1J4 in. of fibrous insulation added on one side of the air space. Solution: Ui can be determined in several ways, by using Table 16, Part A, for example; (a) By going from Column 1 to Column 2 three times, for a total of ly inches of insulation, as follows; enter Column 1 at 0.24 and find Ui 0.166 in Column 2; enter Column 1 at 0.166 and find Ui -- 0.126 in Column 2; enter Column 1 at 0.126 and find Ui *= 0.102 in Column 2. Therefore, for a total of \\4 in. of insulation, use 0.10. (b) More simply, by going from 0.24 in Column 2 to 0.103 in Column 4.-Use 0.10. 3. If there is no column which fully corresponds to the con dition for which you desire the U value, then obtain the answer by means of two or'raore steps--each time using the value ob Example 6: Considering again the wail of Example 5, assume that one-inch blanket insulation is to be installed in mid-space, (Cmiitaed tn p_ ;/j.) 112 CHAPTER 9 1959 Guide Table 12A____ Coefficients of Transmission (U) of Concrete Roor-Ceiling Constructions- {Winter Conditions, Upward Flow) - Coefficient* on **p*e**od in file per (iioort (square foot IFahnaheit degree difference ie temperature between (be err on (he two odes), and are band on did ar (no wind) condition* on boft rid** Example--Floor J 4 Exempt* of Substitution Resistances used are given below in this - table or in Table 8 or 4 Heated room below unheated space . Construction (heat Sow up) Resistance {R) 1. Top surface (still air)....................................... 0.61 2. Asphalt tile and felt.......................................... 0.11 3. Plywood (56 in.)................................................. 0.78 4. Airspace*............................................................. 0.86 5. Concrete slab 4 in: (av. R).............................. 0.40 6. Air space** (8 in.)................................................ 0.86 7. Metal lath and 56 plas. (sand agg.)............... 0.18 8. Bottom surface (still air)................................. 0.61 Total resistance.................................................... 4-84 U - 1/A - 1/4-84 -........................................ 0.23 See value 0.23 in bold face type in table below. Resistances used are given below in this table or tn Table 8 or 4 Replace items 2, 3, and 4 with hard wood block (1Ke in.) on slab Total resistance........................................... 4-84 Deduct 2. Asphalt tile and felt................ 0.11 3. Plywood (56 in.)...................... 0-78 4. Air space.............................,...0.85 1.74 Difference............................- - Add 2. Wood block (l5{e in.)-. 8.60 0.74 Total resistance.... U - l/R = 1/8.84 8.84 . 0.30 Typo of Oodc la Adjn* U Values for Construction wife Added insolation in Air Spac* above Suspended Coffins, 8oe TaMe.M Type of Finish Floor Typo of Coffins Suspended Catting Directly to Slob Gypsum bd. Metal loth (56 taJ end Plas. and plat. Acoustical tile Acoustical On furring On gyp- Plas. ta*-- slued No Ltwt. Sand Lt. wi. Sand aggj agg.) agg.) or dionnels (H "-) i z U. wt. [Sand Oflfl.) oflO-1 H Hi"- H M- X 56 M- 56 m. Hi". ?6 in. Xin. K 5in6. ta z rBeshtence 0.06 0.02 IJ9 MB 0.62 0j6d 0.41 0.47 0J3 J9 1.78 f.51 2.10 Material Av. u U U U U U u U U u 0 U U U R F F G H 1 J K LMN None........................... <T62 "0359 Xei 0l36 0.29 0.36 0.32 0.35 0.34 0.38 0.27 0.24 0.25 0.22 Floor tile* or linoleum (X ia.).................. 0.06 0.60 0.57 0.59 0.35 0.29 0.35 0.32 0.34 0.33 0.38 0.27 0.23 0.25 0.22 2 Concrete* (sand agg-) (4 in:) 0.88 (6 in.) 0.48 O.lf3i Woodblock (lKs in.) on slab............................ 0.74 0.42 Floor on sleepers ' ' Plywood subfloor' (56 in.), felt and SoOr tile* or linoleum (56 in.)........................... . 0.89 0.30 0.41 0.29 0.42 0.28 0.24 0.28 0.30 0.22 0.19 0.22 0.26 0.21 0.28 0.27 0.30 0.23 0;20 0.21 0.19 0.22 0.21 0.23 0.19 0.17 0.17 0.16 3 4 Wood subfloor (aMs in.), felt and hard wood (56 in.)........... 1.78 0.24 0.24 0.24 0.19 0.17 0.19 0.18 0.18 0.18 0.19 0.16 0.15 0:15 0.14 _ None................................. 0.52 0.50 TFl 0.32 0.27 0^32 0.29 0.31 0.31 0.34 0.25 0.22 0.23 0.20 6 6 Floor tile* or linoleum (X in.)...................... 0.06 0.50 0.48 0.50 0.31 0.28 0.32 0.29 0.31 0.30 0.34 0.25 0.22 0.23 0.20 7 Concrete* (sand agg.) . (8m.) 0.64 (10 in.) O.r slab............................ 0.74 0.37 0.36 0.37 0.26 0.22 0.26 0.24 0.25 0.25 0.27 0.21 0.19 0.20 0.18 8 Floor on sleepers Plywood subfloor (56 in.), felt and floor tile* or linoleum (X in.)............................. 0.8i 0.27 0.27 0.27 0.21 0.18 0.21 0.19 0.20 0^20 0.21 0.17 0.16 0.17 0.15 8 9 Wood subfloor (*56s in.), felt and hard wood (56 in.)............ 1.71 0.25 0.22 0.22 0.18 O.lfi 0.18 0.17 0.17 0.17 0.18 0.16 0.14 0.15 0.13 10 4 See text tgT**"" Qi--.taring Orextll Coefficients for basis of ateutations. b To edjtst U velaea far the effect of sdded insulation between framing members, eeeTable 18. * Table 18 ess be only if sleeperspace b non-reflective. The sleeper airspace b' not to be coanted in mint Table 18. *CoomtebaaMmed to bar* a thermal conductivity kat 110 as given in Tabl* 4. * Include* asphalt, rubber, and plastic tile (H in.), ceramic tile on tenaixo (1 in.). Heat Transmission Coefficients of Building Materials 113 Table 12B-------Coefficients of Transmission (U) of Concrete Floor-Ceiling Constructions* (Summer Conditions, Downward How) Coefficient* ere expressed m Bio per.(hovr) (square fool) {Frdtrenheil degree difference in temperature between fee air an fee two rid**), and ore boxed on still air (no wmd) condition* oe both ode* TYPE OF CHUNG Ceding Applied Directly to Slob Suspended Ceffing Gypsum bd. Metoi lath (56 `wJ nd Plot. - and plav Acoustical tS* Type of Finish Floor Acoustical On furrtaf On Pies. ta*-- * gypsum glued (U (Sand (U.. (Sand channels bd. (56 M-l "1 1 * *. (Lt. wt (Sand 1 oggj 56 *" oggj 56bt H in. ta. ta.X plas. aggj H bv aggj H In- agg.) O00-) 56 m. X X X Hta. ,Concrete* (sand (4*in.)> 0. (6 in.) 0. Concrete* (sand agg.) (8 in.) 0.64 (10 io.) 0.80 Rerixtonce_ 4- - 0.08 0.02 IJ9 1.76 0.32 0.84 0.41 CU7 0.13 7.19 MB 1.5) 2J0 Material Av. U U U U U U U U U U U U Ro P Q R S T V W X "T 1 1` Z" 0.45 0.43 0.44 0.29 0.25 0.26 0.24 0.26 0.25 0.28 n "i n in 0.20 0.18 Floor tile* or linoleum (X in.)...................... 0.06 0.44 0.42 0.43 0.29 0.25 0.26 0.24 0.25 0.25 0.27 9.21 0.19 0.20 0.18 2 Wood block UXs in.) on slab............................ 0.74 0.34 0.33 0.33 0.24 0.21 0.22 0.21 0.22 0.21 0.23 0.19 0.17 0.17 0.16 3 Floor on sleepers Plywood subfioor (56 in.), felt and floor tile* or linoleum (56 in.)............................. 0.89 0.23 0.23 0.23 0.18 0.17 0.17 0.16 0.17 0.17 0.18 0.15 0.14 0.14 0.13 4 Wood subfloor f256* in.), felt and hard wood (56 iD.)............ 1.78 0.20 0.19 0.20 0.16 0.15 0.15 0.14 0.15 0.15 0.1C 0.13 0.12 0.13 0.12 5 0.39 0.38 0.39 0.27 0.23 0.24 0.23 0.24 0.23 0.26 n "n n in 0.19 0.17 Floor tile* or linoleum (Hin.)...................... 0.06 0.38 0.37 0.38 0.26 0.23 0.24 0.22 0.24 0.23 0.25 0.20 0.18 0.19 0.17 Wood block (*56 in.) on slab............................ 0.74 0.30 0.30 0.30 0.22 0.20 0.21 0.19 0.20 0.20 0.21 0.17 0.16 0.17 0.15 7 8 Floor on sleepers Plywood-subfloor (56 in.), felt and floor tile* or linoleum (56 in.)............................. 0.89 0.22 0.21 0.22 0.17 0.16 0.16 0.15 0.16 0.16 0.17 0.14 0.13 0.14 0.13 9 .Wood subfloor (*56* in.), felt and hard- 1.78 0.19 0.18 0.18 0.15 0.14 0.14 0.14 0.14 0.14 0.15 0.13 0.12 0.12 0.11 10 * See text section Calculating Overall Coefficient* for basb of calculation*. . To adjust U values tot tbe effect of added insulation between framing members, see Table 18. * Table 18 can be used only if aleeper apace b noareflgetive. The sleeper air space b not to be coanted in using Table 16. Cooawte b etiimw} to bave a thermal conductivity k td 11.0 as given in Table 6. * Includes asphalt,' rubber, and plastic tile (H in.), ceramic tile on terrasso (1 in.). leaving equal air spaces on the two sides. The coefficient Ui is desired for two cases in which fa) the blanket has non-reflective surfaces on both sides, so that both air spaces are non-reflective (E *= 0.82) and, (6) the blanket has one highly reflective surface, so that one of the air spaces is highly reflective (E = 0.05). Solution: (a) In Table 16,.Part A, when U without added insulation ia 0.24, Ui for one inch of fibrous insulation and one oon-reflective air space, is 0.127 in Column 3. To add the second non- reflective air space, enter Column 6 at 0.127, and by interpolating find Ui = 0.112 in Column 9. Use 0.11. (5) Ui for one inch of fibrous insulation and one non-reflec- tive air space ia 0.127 as io (a). To add one E = 0.05 air space, enter Column 8 at 0.127 and by interpolating find Ui " 0.092 in Column 11. Use 0.09. . {Continud r f. iZt.i i 114 CHAPTER 9- 1959 Guide Table 13A .... Coefficients of Transmission (Lf) of Bat Masonry Roofs with Built-up Roofing, with and . without Suspended Ceilings* (Winter Conditions, Upward Row) Tlira Coefficient* ore expressed in Bfo per (hour) (square foot) (Fohranheff degree difference to tewperoture between the atr on (he two sides), and ore based on on outside wind vefpetty of 15 apt) ____________________________________ fxostpl*--K A Cxoa^te of Substitution Resistance! used are given below in this . table or in Table S or 4 Construction (heat flow up) Resistance (R) 1. Outside surface (15 mphwind)................... 0,17 2. Built-up-roofing--K in...................................... O.SS 3. Roof insulation (none)...................................... -- 4. Concrete slab (It- wt. agg.) (2in.).................. 8.88 5. Corrugated metal...................... ....................... 0 6. Airspace*............................................................ 0.85 7. Metal lath and X in. plas. (H-wt. agg.)___ 0.47 8. Inside surface (still air)................................... 0.61 Resistances used are given below in this table or in Table 3 or 4 Replace item 4 with 4 in. concrete slab (gravel agg.) and roof insulation (C -- 0.36} on top of slab. Total resistance........................................... 4-05 Deduct 4. Concrete slab (It. wt. agg.) (2 in.)............. 8.33 Difference................ ................................... .8.43 Add 3. Roof insulation (C ** 0.36)........ 8.78 4. Concrete slab (gravel agg.) 4 in.. 0.44 Total resistance.:............................................... 4-65 Total resistance....................................................... 6.65 V - 1/R - 1/4-05 -....................................... 0.22 V - 1/R - 1/5.65 -............................................ 0.18 See value 0.22 in boldface type in table below. To Adjust U Values for Construction with Added Insulation in Atr Space, See Table 16 Heat Transmission Coefficients of Building Materials 115 Table 138 .... Coefficients of Transmission (G) of Bat Masonry Roofs with Built-up Roofing with and without Suspended Ceiling* (Summer Conditions, Downward Bow) Them coefficient* are expressed in Ste per (hour) (square foot) (Fahrenheit degree difference is temperature between the atr on the two *de*), and are bated on go outride wind vefooty of 7.5 mph . Example--Roof I' 2 Example of Substitution Resistances used are given below in this table or in Table 3 or 4 Construction (heat flow down) Resistance (R) 1. Outside surface (7.5 mph wind)...................... 0.85 2. Built-up roofing (3$-in.)................................... O.SS 3. Roof insulation (none)...................................... 0.00 4. Concrete slab (gravel agg.) (6 in.)................. 0.48 5. Temporary form bd........................................... 0.00 6. Air apace** (8 in.)........................... 1.85 7. Gypsum lath (H in.) and X in* plw- (It- wt. agg.).........................................................................0.64 8. Inside surface (still air).................................... 0.93 Total resistance.............. 3.87 U - 1/R ^ 1/3.87 -........................................ 0.26 See value 0.26 in boldface type in table below Resistances used are given below in this table or in Table 3 or 4 Replace item 3 with roof insulation (C 0.36) and remove suspended ceiling . Total resistance...................................................... 3.87 Deduct 6. Airspace................................... 1.85 7. Gypsum lath (K in.) and X in. pins. (lt. wt. agg.)............... 0.64 Difference............................................ Add 3. Roof insulation (C " 0.36).. 1.98 8.78 Total resistance TM............................. U - 1/R =. 1/4-76 -........................ 4-76 0.21 To odjutf U Value* far Construction with Added fitsufofioA in Atr Space, See Table 16 Material Concrete slabGravel agg. (4 in.).. 0.38 (6 in.).. 0.48 (8 in.).. 0.64 Lt. wt. agg.* (2 in.).. 8.88 (3 in.).. 3.33 (4 in.).. 4 U Temporary............................. Temporary............................. Temporary............................. Corrugated metal*.............. -Insulation bd. (1 in.)____ Insulation bd. (1)4 in.). Glass fiber bd. (1 in.) -- -Corrugated metal*.............. Insulation bd. (1 in.).... Insulation bd. (IK in*) Glass fiber bd. (1 in.)____ Corrugated metal*............. Insulation bd. (I in.).... Insulation bd. (1)4 in ) - Glass fiber bd. (1 m.)------ Gypsum slab* (2 in.).. 1.80 Gypsum bd. (H in.)......... Insulation bd. (1 in.)____ Insulation bd. (1)4 in.).. Asbestos-cement bd.1 (3 in.).. 1A (4 in.).. 8.40 (X in.).................................. Glass fiber bd. (1 in.).. Gypsum bd. 04 in.).......... Insulation bd. (1 in.).... Insulation bd. (1)4 in.).. Asbestos-cement bd. (Kin.) Glass fiber bd. (1 in.) -- Gypsum bd. 04 in-)......... Insulation bd. (1 in.)____ Insulation bd. (IX in.) Asbestos-cement bd. (X in.).......................................... Glass fiber bd. (1 in.)... * See text section r-.l--Overall Coefficient* (or basis of calculation*. * To adjust U value* fer the effect of added insulation between framing member*, kc Table 16. * U values would also apply if alab were poorad oa meUd lath, paper-backed wire, fabric, or esbeetoa^emeat b * Pnia rntn mnmrrl to hare* thermal conductivity k of 110and a density of M0 lb per cu ft. * Concrete assumed to bave a tbcrmal conductivity i of Q-S0 aad a density of 30 lb per cu ft. ( Gypaum alab IX in. thick cinee this is recommended practice. * Gypeum fiber oouciete with 11)1 percent wood ebipe (thermal conductivity k -- l.M). ' h 8ee Table 16 E for V value if roof aad construction with roof insulatioo added to roof deck. Melerial Concrete slabd (Gravel agg.) (4 in.).. 0.38 (6 in.).. 0.48 (8 in.).. 0.64 Lt wt. agg. (2 in.).. 8.88 (3 in.).. 3.33 (4 in.).. 4-4* Gypsum slab* (2 in.).; 1.80 Temporary. Temporary. Temporary. Corrugated metal*... Insulation bd. (1 in.) Insulation bd. (IX in Glass fiber bd. (1 in.) Corrugated metal*. .. Insulation bd. (1 in.) Insulation bd. (lH *n Glass fiber bd- (1 in.) Corrugated metal*... Insulation bd. (1 in.) Insulation bd. (IX in Glass fiber bd. XI id ) Gypsum bd. (H in.). Insulation bd. (1 in.) Insulation bd. OK in Asbestos-cement bd.' (4 in.).. 3.40 Glass fiber bd. (1 in.) Gypsum bd. (X in.). Insulation bd. 0 in.) Insulation bd. OK in Asbestos-cement bd. in.)........................... Glass fiber bd. (1 in.) Gypsum bd. (X in.). Insulation bd. (1 in.) Insulation bd. OK in Asbestos-cement bd.* in.)........................... Glass fiber-bd. (I in.) * Bee text teetioa Calculating Overall Coeffiaeots for basis of --I-- b To adjust U value* for the effect of added insulatioo between framing men * U values would also apply if slab were poured oo metal lath, paper-baeked d Omenta assumed to have a therms; conductivity i of 110 and a density of M0 lb per ft. * Concrete assumed to have a thermal conductivity k of 0.90 a density of 30 lb per cu ft. * Gypsum slab 3M in. thick since this is recommended practice. Gypeum fiber concrete with 1*H percent wood chips (thermal conductivity k -- 1.66). See Table 16 E for U value of roof and ceilins construction with roof insulatioo added to roof deck. 116 CHAPTER 9 1959 Guide Table 14A.... Coefficients of Transmission (U) of Wood or Metal Construction Rat Roofs and ` Ceilings* (Winter Conditions, Upward Row) Coefficients or* expressed tn Bfu per (hour) (niMrr fnnt) (Fgftfggfearf difference in temperate,'* Iwnc the air on the two rider}, ' and or* based upon on outride wind velocity of 75 pfi Example--Roof J.2 Example of Substitution e 7 e Resistances used are given below in this table or in Table 3 or 4 Construction Resistance {R) (Heat flow up) 1. Outside surface (15 mph wind)..................... 0.17 2. Built-up roofing. X in..................................... 0.33 3. Roof insulation (C TM 0-72)............................ 1.89 4. Wood deck (1 in.).................... 0.03 5. Air space6........................ 0.86 6. Gypsum wall board (K in.).............................. 0.88 7. Acoustical tile (X in.)--glued...................... 1.19 8. Inside surface (still air)................................. 0.81 Total resistance............................................... 6.84 U - 1/R - 1/5.84................................' 0.17 See value 0.17 in boldface type in table below. Resistance* need are given below in this table or *'n Table 8 or 4 Replace item 4 with 2 in. wood deck (ex posed to inside) and omit items 5, 6, and 7. Total resistance..................................................... 6.84 Deduct 4. Wood deck (1 in.).................. 0.08 5. Air space................................. 0.86 6. Gypsum wall board (% in.).. 0.88 7. Acoustical tile (K ia.) glued.. 1.10 3.34 Difference............................................................... 8.60 Add 4. Wood deck (2 in.).................................... 8.08 Total resistance.................................................... 4-53 U - UR - 1/4.53 -........................................... 0.22 To Adjust U Values for Construction with Added tnsutatioa in 'Air Space, See Table 76 Type of Deck (Bu3t*up Roof in AH Corns) _ Material muj-- A * Added on Top of Deck* Gypsum Bd. (X in. end Flos.) Con duct- Retb- tunc* of fatswL i C* U. wt. N"* None age. X In- 0.32 0.64 UUU AB C Sand agg. X*. 0.41 U 0 0.08 None __ 0.72 1.38 0.35 8.78 0.24 4.17 0.19 6.88 0.15 6.67 0.12 8.33 0.4S 0.31 0.28 0 W 0.22 0.20 0.21 0.17 0.16 0.16 0.13 0.13 0.W 0.12 0.11 0.11 o.ii 0.10 0.10 0.09 0.08 0.30 0.21 0.16 0.13 0.12 0.10 0.09 8.03 3.88 0.72 0.36 0.24 0.19 0.15 0.12 0.72 0.36 0.24 0.19 0.15 0.12 __ 1.89 8.78 4.17 6.86 6.67 8.33 _ 1.89 8.78 4.U 5.88 6.67 8.33 ft 32 0-23 0.22 ft 22 O.li 0.17 0.17 0.14 0.13 ft 14 0.12 0.11 0.12 O.lt 0.10 0 K 0 Of 0.09 0.09 0.08 0.08 0.23 0.17 0.14 0.12 0.10 0.09 0.08 0.23 0.18 0il7- 0.18 0.11 0.14 0.14 0.14 0.14 0.12 0.12 0.12 0.12 O.IC 0. IQ 0.10 0.11 0.01 0.09 0.09 O.Of O.Of 0.08 0.08 0.08 0.07 0.07 0.07 Metal lath and Flos. U. wt. ogg. X 0.47 Sand agg. X in- 0.13 UU EF 0.29 0.21 0.16 0.13 0.12 0.10 0.09 0.38 0.22 0.17 0.14 0.12 0-10 0.09 0-22 0.17 0.14 0.12 0.10 0.09 0.08 0.24 0.18 0.14 0.12 0.11 0.09 0.08 0.18 0.14 0.12 0.10 0.09 0.08 0.07 0.19 0.15 0.12 0.10 0.09 0.08 0-07 IrmL Bd. IX i"J Plain (1.43) Of H in. plot, sand ogg. 0.52\ 1.47 U G 0.23 0.17 0.14 0.12 0.10 0.09 0.08 0.18 0.15 0.12 0.10 0.09 0.08 0.07 ' 0.15 0.12 0.11 0.09 0.08 0.07 0.07 Acoustical T9* On Furring On Gypsum Bd. (HW x*. Km- Xfo. 7.79 778 1.51 2J0 UU H1 0 J U K 0.24 0.21 0.22 0.18 0.16 0.17 0.14 0.13 0.14 0.12 0.11 0.12 0.11 0.1U 0.10 0.09 0.09 0.09 0.08 0.08 0.08 0.20 0.16 0.13 o.n .0.10 0.09 0.07. 0.19 0.17 0.18 0.15 0.14 0.15 0.13 0.12 0.12 0.11 0.16 0.10 0.16 o.os 0.09 008 0.U8 0.08 0.0/ 0.0/ 0.07 0-16 0.13 0.11 0-10 0.09 0.08 0.07 0.16 0.14 0.15 0.13 0.12 0.12 0.11 O.lt 0-10 O.OU 0.09 0.09 0.09 0.05 0.08 0.08 0.0/ 0.07 0.07 0.0/ 0.07 0-14 0.11 0.10 0-09 0-08 0.07 0.06 J E Z 1 i 3 4 5 6 7 8 9 10 11 12 13 14 16 16 17 18 19 20 21 Preformed slabs--wood fiber and cement binder- 8.60 3 in. 6.40 None __ -- None 0.72 1.89 0.36 8.78 0 ,0.24 4.17 0.19 6.88 0.15 6.67 0.12 8.83 0.21 0.11 0.16 0.15 0.13 0.13 0.90 0.44 0.38 0.4( 0.21 0.25 0.26 0.2< 0.19 0.11 0.1( 0.15 0.16 o.n 0.13 0.11 0.11 0.11 0.11 0.09 0.09 0.17 0.13 0.42 0.27 0.19 0.15 0.13 0.11 0.09 0.17 0.13 0.41 0.26 0.19 0.15 0.13 0.11 0.09 0.18 013 0.48 0-29 0.21 0.16 0.14 0.11 0.10 0.14 0.11 0.29 0.21 0.16 0.13 0.12 0.10 0.09 0.15 0.14 0-14 0-12 0.11 Oil 0.32 0.27 0.29 0.22 0.19 0-21 0.11 0.15 0-16 0.14 O.li 0.13 0.12 0.11 0.11 O.lt O.li 0.10 0.09 0.08 0.08 0.13 0.11 0.25 0.18 0.15 0.12 0.11 0-09 0.08 22 23 24 25 28 27 28 29 30 See text eectioo Cxlffalxtimg Ovemll Coefficients tor basis of cilcufetinpa. b To adjust U values (or the effect of added insulation between framing members, see Table lfl. ' Wood deck 1, 3. and S in. b assumed to be *Hi, Ift. and 2tt in. thick, respectively. The thermal conductivity k b assumed to be 0.80. . * If a vapor barrier k used beneath roof insulation it will have a negligible effect on the V value. For information oo vapor barrier requirements see Chapter 10, Moisture in Building Construction. Heat Transmission Coefficients of Building Materials 117 Table 148 .... Coefficients of Transmission (t/) of Wood or Metal Construction Flat Roofs and Ceilings* (Summer Conditions, Downward Row) . Coefficients or* expressed in Bfu per (how) 1square foot) (Fahrenheit degree difference in temperahr* between the air oo the two tides), and am based upon an outride 'wind velocity of 7.5 mph Example--Roof F' 27 Example of Substitution . s' / if . s s<*^ Ss / '5\ ^ IXr' N Srf Jp JF - Resistances need are given below in this ' table or in Table* 3 or 4 Construction Resistance (R) l. Outside surface (7.5 mph wind).................... 0.85 2. Built-up roofing (K n-)................. '.............. 0-33 3. Roof insulation (C -- 0.24)*.......................... 4.17 4. Meul deck.......................................................... 0.00 5. Air spaceb........................................................... 1.88 6. Meta) lath and \ _ 7. X in. plas. (sandagg.)/ ............................... 8. Inside surface (still air)................................... 0.98 2 * *7* Total resistance................................................ 7.03 U -- l/R = 1/7.03 -..................................... 0.14 See value 0.14 in boldface type in table below. Resistances used are given below in thi* table or in Table* $ or 4 Replace item 3 with roof insulation (C -- 0.36) and items 6 and 7 with metal lath and X in. plas. (It. wt. agg.).............. Total resistance............. .................................... 7.03 Deduct 3. Roof insulation (C => 0.24)... j.17 6. Metal lath and - \ n ie i en 7. X i- plas. (sand agg.)/.....................A_ Difference............................................................... 8.78 Add 3- Roof insulation (C *= 0.36)....... 8.78 6. Metal lath and \ n . 7. X in. plas. (It. wt. agg.)/............. Total resistance...................................................... 5.98 U - l/R 1/5.05 -.......................................... 0.17 To Adjurf U Values for Construction with Added Insulation in Air Space See Table 76 limitation Added on Top Type ef Deck {Built-up Roof fb All Carer] of Dec** Coo- duct- None Kerb- tance of fosui lUststaoce---- -- ~r~ -* Material .U *A' ' Gyprwm Bd. (K fn.) NTM 0.32 It. wt. X M0.64 Sand X 0.41 UU U B' c O' Type of Ceiling Metal loth Imut Bd. (X *nj Acoustical TBe It. wt Sand Plain (1.43) On Furring On Gypsum Bd. IX W Xbv X piax. xond agg. 1.52 Km- X* X - Vein. 0.47 0.13 f.47 I.I9 176 -5? 2J0 uU U UU U U E' f G' H' I' r K' 1 z Wood* 1 in. 0.98 None 0.72 0.36 0.24 0.19 0.15 0.12 1.89 8.78 4.17 5.88 8.67. 8.88 ft 4ft .0.26 0.19 0.15 0.12 0.11 0.09 0-25 0.23 o.is 0.17 0.15 0.14 0.12 0J2 0.-11 0.10 O.Of 0.09 0.08 o.os 0.24 0.18 0.14 0.12 0.11 0.09 0.08 0.24 0.18 0.14 0.12 0.11 0.09 0.08 0.26 0.19 0.15 0.12 0.11 0.10 0.08 Wood* 2 in. Wood* 3 in. 8.05 None 0.72 / .89 0.36 8.78 0,24 4-17 0.19 6.86 0.15 6.87 0.12 8.88 None _ 0.72 1.89 0.36 8.78 3.83 0.24 4.17 - 0.19 6.88 0.15 6.67 0.12 8.88 0.28 0.20 0.19 0.21 0.15 0.15 ft 16 0.13 0.12 0.13 0.11 0.10 0 H 0.1C 0.07 0.16 0.09 0.08 0.08 0.07 0.07 ft 21 0.16 0.15 0.16 0.13 0.12 0.13 0.11 0.11 0.11 0.10 0.09 0.16 0.09 0.08 0.09 0.08 0.08 0.08 0.07 0.07 0.19 0.15 0.13 0.11 0.10 O.OS 0.07 0.16 0.13 0.11 0.09 0.09 0.08 0.07 0.19 0.15 0.12 O.lt 0.10 0.08 0.07 0.15 0.13 0.11 0.09 0.09 0.08 0.07 0.20 0.16 0.13 0-11 0.10 0.09 O.OS 0.16 0.13 0.11 010 0-09 0.08 0.07 Preformed slabs--wood fiber and cement binder 2 in. 3 in. 3.60 5.40 Roof Deck . .0 None None -- None _ 0.72 1.89 0.36 8.78 0.24 4.17 0.19 5.86 0.15 6.67 0.12 8.88 0.20 0.15 0.14 0.14 0.12 0.11 0.67 0.33 0.30 0.35 0.23 0.21 0.23 0.17 0.16 0.18 0.14 0.13 0.15 0.12 0.12 0.12 0.10 0.10 0.10 0.09 0.09 0.15 0.12 0.32 0.22 0.17 0.14 0.12 0.10 0.09 0.15 0.12 0.31 0.22 0-17 0.14 0.12 0.10 0.09 0.15 0.12 0.35 0.24 0.18 0.14 0.12 0.10 0.09 0.19 0.15 0.13 0.11 0.10 0.08 0.07 0.16 0.13 0.11 0.10 0.09 0.08 0-07 0.13 0.11 0.10 0.09 0.08 0.07 0.06 0.13 0.10 0.24 0.18 0.14 0.12 0.11 0.09 0.08 0.20 0.18 o.i9 O.K 0.15 0.15 O.li 0.12 0.13 o.l] O.U O.ii 0.K O.Of 0.10 O.Of 0.01 0.08 0.08 0.07 0.07 0.17 0.14 0.12 0-10 0.09 0.08 0-07 1 % S 4 6 6 7 0.17 0.15 0.16 0.14 O.U 0-13 0.11 0.1] 0.11 0.1C (MW 010 O.OS O.OS 0.09 O.OS o.os 0.08 0.07 0.07 0.07 0.15 0-12 0.10 0.09 0.08 0.07 0-07 8 9 10 11 IS 13 14 0.14 0.13 0.13 0.12 0; 11 0-11 0 HI 0.09 0.10 ft.09 0.08 0.09 0.08 0.08 0.08 0.07 0.0/ 0-07 0.06 0.06 0.06 0-12 0.11 0.09 0.08 0.07 0.07 0.06 15 16 17 18 19 so SI 0.13 0.12 0.13 0.11 0.10 0.10 0.26 0.22 0-24 0.19 0.17 0.18 0.15 0.14 0.14 0.12 0.12 0-12 0.11 O.U 0.10 u.uy O.Of) 0.09 0.08 0.08 O.OS 0.12 0.10 0.21 0.16 0.13 0.1! 0.10 0.09 0.08 22 S3 34 25 26 27 28 29 SO ` See text eectioo Celmileting Overall Coefficients for b a ct aleulationa. b To adjust 17 values tar the effect of a " Wood deck 1,1, and t in. b assumed to be *Hr, 1H, and JM, in. thick, respectively. The thermal conductivity * is assumed to be 0.80. . If a vapor barrier b used beneath roof insulation it will have a negligible effect on the U value. Far information on vapor barrier requirements m ter 10, Moisture in Building Construction. ', , 118 CHAPTER 9 195.9 Guide CooBdoots are and are Table 15 .... Coefficients of Transmission (U) of Pitched Roofs*- b . a Bfu per (hoaH (square foot) (Fahrenheit degree difference an Nmpeffftiare between the air on Ibe two sidei). on on outdde.wiod refodty of 15 mph for hod flow upward end 7.5 mptt for hoof flow.downward________ . ftainpk--Roof C Example of Substitution Resistances used are given below in this table or in Table 3 or 4 Construction Resistance (fi) (Heat flow up) . 1. Outside surface (15 mph wind).................... 0.17 2. Slate shingles (M in.)................................... v 0-05 3. Building paper.................................................. 0.06 4. Wood sheathing (*H* in-).............................. 5. Air space"........................................................... 0.90 6. Gypsum lath in.)....................................... 0.33 7. Pfas. (sand agg.) 0$ in.)................................. 0.09 8. Inside surface (stillair)................................... O.t Total resistance.............................................. 3.19 -U - l/R - 1/5-10...............:..................... . 0.31 See value 0.31 in' boldface type in table below. Resistances used are given below in this table or. in Table 3 or 4 Find U value for same construction with heat flow down (summer conditions) Total resistance..................................................... 3.19 Deduct 1. Outside surface (15 mph wind)........................................ 0.17 5. Air space.................................. 0.90. 8. Inside surface (still air)........ 0.63 1.69 Difference.............................................. ............... 1.60 Add 1- Outside surface (7.5 mph wind).. 0.36 5. Air space................................... 0.89 8. Inside surface (still air)........ 0.70 1. Total resistance.................................................... 3. U - l/R - 1/5.40................................................ 0. To Adjust U Valve* for Conxfrucfroo wtlfi Added Insulation between Fraaaag Members, See Table 16 86 I S Direction of Heat Flow --* Upward Row Winter Conditions Downward Row Summer Conditions Rafter Space Insulated Rafter Space Unventdated, Not to be Further Insulated Insulated ted Type of Ceding (Applied Oirecffy to Roof Rafters] ' Material Raasfonce Asphalt shingles budding paper e5 ? He* 11 = 114 0 111 6 V Jw ia. 0c i|il -542"o-S a *1" w * _c ci * it /I*** 1^ 0.95 1.40 1.09 0.87 - R u u U Uu Asphalt shingle*, budding poper 5-2 8- ijii 10 a 0 a m12 w sc _ !il? i| ^ W F w m a 5 *! oii 66 " < 0.95 1.48 1.09 0.87 uU U U as if a* . -- u A8 c D FG H 1J ^ <M YGypsum lath id.) in.plas. (lt.wi.agg.). Gypsum lath in.) and in. plas. (sand __ 0.33 0.64 0.41 0.57 0.34 0.30 0.33 0.44 0.29 0.26 0.2S 0.47 0.32 0.27 0.13 0.36 0.30 0.53 0.32 0.29 O.Si 0.31 0.34 0.60 0.66 0.51 0.40 0.35 0.54 0.30 0.26 0.31 0.46 0.28 0.24 0.34 0.52 0.29 0.25 0.33 0.50 0.29 0.25 0.37 0.61 0.32 0.48 0.29 0.27 0.2S 0.28 0.53 0.56 0.31 0.47 0.28 0.41 0.30 0.45 0.30 0.44 Y 1.43 0.25 0.22 Insul. bd. lath and if1- plas. (sand agg.)... 1.63 0:24 0.21 0.24 0.23 0.25 0.34 0.23 0.20 0.25 0.33 0.22 0.20 0.22 0.22 0.23 0.31 0-23 Acoustical tile 1.S1 1.19 1.78 0.24 0.26 0.23 0.21 0.23 0.19 0.20 Wood lath and K in- pins- (sand agg.)........... 6.40 0.33 0.28 0.23 0.25 0.20 0.22 0.31 0.25 0.27 0.21 0.23 0.33 0-37 0.26 0.30 0.22 0.24 0.20 0.21 0.20 0.21 0.18 0.19 0.34 0.52 0.29 0.26 0.22 0.23 0.19 0.20 0.28 0.23 0.24 0.20 0-21 0.30 0.34 0.28 0.30 0.46 See text nr**" OverxU Coefficients (ar basis of calculations. h Pitch ol tod--45 deg. .. . * To adjust U values for the effect of edded insulation between framing members, see Table IS. . a When insolation b installed between rafters, the space above should be ventilated and in thb ease the roof construction b disregarded in calculation of V values. To adjust V values for {etched roof construction with added insulation between framiog members, use the sverae of values for bonsontal and verbal beat fibw in Table 16A and either IOC or tOD depending on direction of heat flow. Heat Transmission Coefficients of Building Materials 119 Table 16 .... Determination of U Value Resulting from Addition of Insulation or Air Spaces to Uninsulated Building Sections* PART A. WALLS' U Vefoeb Without Added laudation Cot 1 Rbreus Insulation" Thickness--inches H1 23 23 4 5 One Air SpaceW Effective fmusivrfy4 E 0.62* 0.20 0.05 fi 7 8 Two Air Spaces of Effective Three Air Spaces of Effective Etsisdvity* E EsaUdvity* E 0.62 0.20 0.05 0.62 0.20 0.05 9 10 II 12 13 14 0.70 0.60 0.45 0.40 0.304 0.284 0.246 0.230 0.194 0-1S6 0.168 0.161 0.113 0.110 0.104 0.101 0.080 0.078 0.075 0.074 0.752 0.630 0.460 0.409 0.463 0.412 0.331 0.299 0.380 0.341 0.280 0.258 .0.437 0-392 0.318 0.291 0.240 0.225 0.195 0.185 0.189 0.177 0.158 ' 0.149' 0.298 0.276 0.237 0.222 0.150 0.144 0.130 0.125 0.112 0.108 0.098 0.095 0.35 0.30 0.28 0.26 0.212 0.192 0.184 0.175 0.152 0.142 0.138 0.133 0.097 0.093 0.091 0.089 0.072 0.069 0.068 0.066 0.354 0.30 0.28 0.28 0.267 0.234 0.221 0.208 0.234 0.207 0.196 0.185 0.282 0.232 0.220 0.207 0.172 0.158 0.151 0.144 0.140 0.130 0.125 0.120 0.205 0.186 0.178 0.169 0.119 0.112 0.108 0.104 0.092 0.087 0.084 0.082 0.24 ' 0.22 0.20 0.18 0.166 0.156 0.145 0.134 0.127 0.121 0.115 0.108 0.087 0.084 0.081 0.078 0.065 0.064 0.062 0.060 0.24 0.22 0.20 0.18 0.194 0.180 0.165 0.150 0.173 0.161 0.149 0.137 0.194 0.180 0.166 0.152 0.137 0.129 0.120 0.112 0.115 0.110 0.104 0.098 0.160 0.150 0.140 0.129 0.100 0.096 0.091 0.086 0.079 0.076 0.073 0.069 0.16 . 0.14 0.12 0.10 0.123 0-111 0.098 0.085 0.100 0.092 0.083 0.073 0.074 0.069 0.064 0.058 0.057 0.054 0.051 0.047 0.16 0.14 0.12 0.10 0.136 0.120 0.105 0.089 0.124 a. 111 0.098 0.084 0.137 0.122 0-107 0.091 0.103 0.094 0.084 0.074. 0.090 0.083 0.075 0.066 0.118 0.106 0.094 0.082 0.080 0.075 0.068 0.061 0-065 0.061 0.056 0.051 0.08 0.070 0.062 0.050 0.042 0.08' 0.073 0.068 0.074 0.062 ' 0.056 0.068 0.053 0-045 * For constructions with air spaces as insulation, coefficients are hrarri on National Bureau of Standards data in Housing Research Pcper No. 32 (U- S. Government Printing Office. Washington, D. C.). * Based on an indooroutdoor temperature difference of 70 F deg, and a mean temperature of 80 F. Values are applicable conservatively to winter and summer condi- b U yalue taken from Tables S to 15, baaed on one aonreflective IW-in. air space between framing members. . * Thermal conductivity of fibrous or bulk insolation taken sa0.J7Btu per (hr) (aqft) (F deg per in.). ' d For values of effective emissivity E of air space, see Table J, Section B. , * Certain U values in Column 6 differ from Column 1 because they are adjusted to the specific temperature drop across the air space in question as affected by the U value of the construction. PART B. FLOORS'--HCAT FLOW DOWN 0 Value* Without Added Insulation Fibrous fiuniation* TJudcnesr--inches Y1 2 3 One Air Space of Effective Emssrnty> B 0.82 0.20 0.05 Two Air Spoces of Effective Three Air Spaces of Effective Emissivity1 E Emissivity1 E 0.82 0.20 0.05 0.82 0.20 0.05 Cot 1 2 3 4 S 6 7 8 9 10 11 12 13 H 0.70 0.60 0.50 0 45 0.305 0.284 0.260 0.246 0.195 0.186 0.175 0.16$ 0.113 0.110 0.106 0.104 0.080 0.078 -0.076 0.075 0.70 0.60 0.50 0.45 0.240 0.236 0.210 0.200 0.114 0.111 0.106 0.103 0.377 0.346 0.310 0.290 0.122 0.118 0.114 0.111 0.057 0.056 0.055 0.055 0.282 0.246 0.228 0.2J7 0.086 0.084 0.082 0.081 0.042 0.041 0.041 0.040 0.40 0.35 0.30 - 0.28 0.230 0.212 0.192 0.184 0.161 0.152 . 0.142 0.138 0.101 0.097 0.093 0.091 0.074 0.072 0.069 0.068 0.40 0.35 0.30 0.28 0.189 0.176 0.162 0.156 0.100 0.096 0.091 0.089 0.268 0.244 0.219 0.208 0.107 0.103 0.098 0.096 0.054 0.052 0.051 0-050 0.205 0.192 0.175 0.168 0.079 0.077 0.074 0.073 0.040 0.040 0.039 0.039 0.28 0.24 0.22 0.20 0.175 0.166 0.156 0.145 0.133 0.127 0.121 0.115 0.089 0.087 0.084 0.081 0.066 0.065 0.064 0.062 0.26 0.24 0.22 0.20 0.150 0.143 0.136 0.128 0.087 0.084 0.081 0.078 0.197 0.185 0.173 0.160 0.094 0.091 0.088 0.084 0.049 0.048 0.047 0.046 0.161 0.153 0.145 0.136 0.072 0.070 0.068 0.066 0.038 0.038 0.037 0.036 0.18 0.16 0.14 0.12 0.134 0.123 0.111 0.098 0.108 0.100 0.092 0.083 0.078 0.074 0.069 0.064 0.060 0.057 0.054 0.051 0.18 0.16 0.14 0.12 0.119 0.109 0.099 0.088 0.074 0.070 0.065 0.060 0.148 0.133 0.118 0.103 0.080 0.076 0.071 0.066 0.045 0.044 0.042 0.040 0.126 0.116 0.105 0.094 0.064 0.061 0.058 0.054 0.036 0.035 0.034 0.033 0.10 0.08 0.085 0.073 0.058 .0.047 0.10 0.076 0.054 0.089 0.058 0.037 0.081 0.049 0.031 0.070 0.062 0.050 0.042 0.08 0.063 0.047 0.072 0.050 0.033 0.068 0 044 0.028 * For construction with air spaces as insolation, coefficient are bemid on National Bureau of Standards data in f/eussag Rami Poprr No. 32 (U. 8- Government Printing Office. Washington, D. C ). - * Based on s temperature difference of 60 F deg from air to air, and a mean temperature of 50 F. * U value taken from Tables 11 and 12, in which it b ----< that the air space between joists or above the suspended ceiling b nonrefiective (B - 0.82), and b 8 in. thick. ' . h Thermal conductivity of fibrous or bulk insulation taken ss0.37 Btu per (hr) (aqft) (P deg per in.). 1 For values of effective emissivity B of sir space, see Table 3, Section B. . 120 CHAPTER 9 1959 Guide U Vofck WiAooi Added tiuohfioo . Table 16-------Determination of U Vajue Resulting from Addition of Insulation or Air Spaces to Uninsulated Building Sections* (Continued) PART C. CEILINGS--HEAT FLOW UP1 (WINTER CONDITION) Etbrou* loadatioo Tbiduwu--laches On* Air Spec* of Effective Emfsrvfy"-E Two Air Spaces of Effective EmisstvflyTM E Hire* Air Space* of Effective Emitavdy9 E - H 2 3 0.32* 0.20 0.05 0.32 0.20 0.05 0.82 0.20 0.05 Col 1 234 6 7 s 9 10 11 12 . 13 14 0.70 0.60 0.50 0.45 0.305 0.284 0.260 0.246 0.195 0.186 0.175 0.168 0.113 0.110 0.106 0.104 0.080 0.078 0.076 0.075 0.690 0.588 0.488 0.438 0.472 0.417 0.361 0.331 0.403 0.362 0.318 0.295 0.427 0.385 0.339 0.316 0.262 0.244 0.224 0.212 0.216 0.204 0.189 0.180 0.307 0.284 0.258 0.243 0.180 0.160 0.154 0.131 0.126 0.40 0.35' 0.30 0.28 0.230 0.212 0.192 0.184 0.161 0.152 0.142 0.138 0.101 0.097 0.093 0-091 0.074 0.072 0.069 0.068 0.389 0.340 0.292 0.272 0.300 0.269 0.237 0.224 0.270 0.244 0.215 0.203 0.288 0.199 0.260 0.185 0.230 0.168 0.217. . 0.161 0.170 0.158 0.145 0.140 0.227 0.209 0.189 0.181 0.125 0.121 0.104 0.26 0.24 0.22 0.20 0.175 0.166 0.156 0.14S 0.133 0.127 0.121 0.115 0.089 0.087 0.084 0.081 0.066 0.065 0.064 0.062 0.253 0.234 0.214 0.195 0.211 0.199 0.186 0.173 0.19i 0.179 0.166 0.154 0.204 0.191 0.178 0.164 0.154 0.146 0.137 0-128 0.134 0.128 0.120 0.114 0.172 0.163 0.153 0.143 0.104 0.088 0.18 0.16 0.14 0.12 0.134 0.123 0. Ill 0.098 0.108 0.100 0.092 0.083 0.078 0.074 0.069 0.064 0 060 0.057 0.054 0.051 0.176 0.156 0.137 0.118 0.159 0.146 0.132 0.118 0.141 0.128 0.115 0.101 0.150 0.136 0.120 0.105 0.119 0.109 0.099 0.088 0.106 0.098 0.090 0.080 0.132 0.121 0.109 0.096 0.097 0.090 0.075 0.073 0.068 . 0.10 0.08 0.085 0.070 0.073 0.062 0.058 0.050 0.047 0.042 0.099 0.079 0.105 0.091 0.088 0.074 0.090 0.073 0.076 0.064 0.071 0.061 0.082 0.067 0.067 0.058 0.062 0.056 * For construction with six spec** u ineuUtion, coefficient* are bod oo Nation*! Bureau of Standards date in HoutU* IT.imrr* Fopcr No. 32 (U. B. Government Printing Office, Washington, D. C.). 1 Baaed on a temperature difference of 75 dec F from air to air, and a mean tenspcratere of 40 F. k U value taken from Table* It, 12, U-A, 14-A.aad 15, in which it iaaasnmed that the airapace between joist* c* above the suspended tailin* b nonraffeetiTe (E - 0.S3), and b 8 in. thick. . 1 Thermal conductivity of fibrous or bulk insulation taken as 0.27 Btu per (hr) (sq ft) (F dec per in.). For values of effective embaivity B of air apace, see Table 3, Section B. . " Certain U values is Column 0 differ from Column 1 because they are adjusted to the specific temperature drop across the air sjace in question as effected by the V value of the construction. PART D. CEILINGS--HEAT FLOW DOWN0 (SUMMER. CONDITION) U Vabe* Without Added Intufatioa Fibrous Insulation0 Thickness-- Inch** 1 23 One Air Space cfaEffectiv* Emittivityr E 0.82 0.20 0.05 Two Air Spaces of Effective Emiuhrity*-E Dire* Air Space* of Effective Emiaivity* B 0.82 0.20 0.05 0.82 0.20 0.05 Col 1 34 6 7 8 9 10 11 12 13 . M 0.70 0.60 0.50 0.45 0.305 0.2S4 0.260 0.246 0.195 0.186 0.175 0.168 0.113 0.110 0.106 0.104 0.080 0.078 0.076 0.075 0.704 0.602 0.501 0.450 0.269 0.252 0.231 0.220 0.119 0.116 0.112 0.108 0.423 0.384 0.340 0.316 0.144 0.139 0.133 0.128 0.061 0.060 0.059 0.058 0.306 0.284 0.260 0.246 0.103 0.097 0.095 0.046 0.044 0.40 0.35 0.30 0.28 0.230 0.212 0.192 0.184 ' 0.161 0.152 0.142 0.138 0.101 0.097 0.093 0.091 0.074 0.072 0.069 0.068 0.400 0.350 0.300 0.280 0.206 0.192 0.175 0.168 0.105 0.100 0.095 0.093. 0.291' 0.264 0.234 0.222 0.123 0.118 0.112 0.109 0.057 0.056 0.055 0.054 0.230 0.213 0.193 0.185 0.092 0.090 0.086 0.085 0.044 0.042 0.042 0.26 0.24 0.22 0.20 0.175 0.166 0.156 0.145 0.133 0.127 0.121 0.115 0.089 0.087 0.084 0.081 0.066 0.065 0.064 0.062 0.260 0:240 0.220 0.200 0.160 0.152 0.144 0.135 0.090 C.087 0.084 0.081 0.209 0.195 0.182 0.168 0.105 0.102 0.098 0.094 0.054 0.053 0.052 0.050 0.176 0.167 0.157 0.146 0.083 0.075 0.041 0.040 0.039 0.18 0.16 0.14 0.12 0.134 0.123 0.111 0.098 0.108 0.100 0.092 0.083 0.078 . 0.074 0.069 0.064 0.060 0.057 0.054 0.051 0.180 0.160 0.140 0.120 0.125 0.115 0.104 0.093 0.077 0.073 0.069 0.063 0.154 0.139 0.124 0.108 0.089 0.084 0.078 0.072 0.049 0.047 0.045 0.042 0.135 0.124 0.111 0.098 0.072 0.064 0.059 0.038 0.038 0.037 .0.035 0.10 0.08 0.085 0.070 0.073 0.062 0.058 0.050 0.047 0.042 0.099 0.079 0.080 0.068 0.056 0.048 0.091 0.074 0.064 0.054 0.039 0.034 0.084 0.070 0.054 0.033 0.046 ` 0.030 Based on a temperature difference of 85 F def from air to air, and a mean temperature of 100 F. * V value takes from Tables 11,13,18-B, 14-B, and 15, is which it b assumed that the air apaoe between jobta or above the suspended ceilinc b nonreflective (E - 0.82), and b 8 in. thick. ` - .' 15 Thermal conductivity of fibroua or bulk insulation takes as 0-27 Btu per (hr) (sq ft) (F dec per in.). 1 For vafoee of effective embaivity S of air space, see Table 3. Section B. ' Heat Transmission Coefficients of Building Materials 121 Table 16 .... Determination -of U Value Resulting from Addition of Insulation to Uninsulated Building Sectiom (Concluded) '' (For me with Tobies 13A and 138) PART E. FLAT ROOFS AND CEILINGS WITH ROOF DECK Conductance C of Roof-Dock Insulation U Value of Root without Roof-Deck Insulation* 0.12 0.15 0.19 0.24 0.36 0.72 UU UUU U 0.10 0.15 0-20 0.25 0.30 0.35 0.40 0.50 0-60 0.70 . : ' . : 0.05 0.07 0.08 0.08 0.09 0.06 0.08 0.09 0.09 0.10 0.07 0.0s 0.10 0.11 0.12 0.07 0.09 0.11 0.12 0.13 0.08 0.11 0.13 0.15 0.16 0.09 0.12 0.16 0.19 0.21 0.09 0.09 0.10 0.10 0.10 0.10 0.11 0.12 0.12 0.12 0.12 0.13 0.14 0.14 0.15 0.14 0.15 0.16 0.17 0.18 0 18 0.19 0.21 0.22 0.24 0.24 0.26 0.29 0.33 0.35 * Interpolation or mild extrapolation may be used. CORRECTION FOR FRAMING Correction for parallel heat flow through framing and in sulated areas may be made by use of Fig. 6. Correction for the effect of framing should, be applied after final U, and U, values have been obtained for a given construction. In many cases this correction may be omitted. Example 7: Consider a frame wall with 2-in. blanket insula tion which has a {/< value of 0.08. By calculation it is found that heat loss from the area backed by framing members (/,) is 0.13. UJXJi is 1.63. From Fig. 6 if 15 percent of wall area is backed by framing, the value U*JUi 1.1. is therefore 1.1 X 0.08 - 0.088. space under various conditions of ventilating air temperatures and rates, ceiling resistance, roof or sol-air temperatures, and surface emissmties.u Ventilating air temperature is the out door design temperature. The total resistance, l/U, obtained by adding the ceiling and attic resistances can be converted to a U value so that the heat gain may be calculated. The applicable temperature dif ference is that difference between room air and sol-air tem perature or between room air and roof temperatures. (See footnote d, Table 17.) Table 17 may be used for both pitched and flat residential roofs over attic spaces. When there is an attic floor, the ceil ing resistance should be that which applies to the complete ceiling-floor construction. All values in Table 16, Part D, include the resistance of a non-reflective surface facing the attic space. Therefore, if separate calculations are made, include only the value of a . non-reflective surface and not the value of a reflective surface in determining ceiling resistance. The use of Table 17, Part B, will account for this reflection surface. ' Example 8: Determine tbc beat gain for a 1000 sq ft ceiling of %-in. gypsum board and light weight aggregate plas ter, with no flooring above, when insulated with a 2-in. foil- enclosed fibrous blanket. The blanket is installed so as to form a reflective air space between the ceiling and the blanket. The attic has a gable roof which meets the ventilation requirements in Table 3, Chapter 10. (Use ventilation rate of 0.1 cfm per sq Design temperatures are: indoor air -- 75 F, outdoor air -- 95 F, and sol-air -- 160 F. . Solution: From Table 11, for beat.flow down, the U value for this ceiling G3 without insulation is 0.40. Referring to Table 16, Part D, with the value 0.40 in Column 1, find Ui * 0.101 in Column 4; enter Column 1 at 0.101 and find Vi -- 0.056 in Column 8. Correct for framing (8 in. joists on 16 in. centers) from Fig. 6 and find corrected ceiling coefficient U, ~ 0.059; - 17.0. By interpolation in Table 17, Part B, using 95 F ventilation air and 160 F sol-air temperatures, the effective attic resistance The overall coefficient for the combined ceiling and attic is: Fig. 6 .... Correction for Effect of Framing in Insulated Building Sections VENTILATED ATTICS--HOW TO USE TABLE 17 Tabic 17 is intended to be used with Table 11, Part D of Table 16, and Fig. 6, or when ceiling resistance is known. Its purpose is to determine the resistance to heat flow of the attic U, ------------ ------------------ - 0.04 Re + ft. 17.0 + 8.2 Heat gain - 7* A ((, -- l<) - 0.04 X 1000 X (160-75) - 3400 Btuh -* COMBINED CEILING AND ROOF COEFFICIENTS If the attic space between the ceiling and roof is unheated and not ventilated, the combined coefficient from room air be low the ceiling to exterior air can be calculated from the fol lowing formula: _1_ _1_ Rt Ua t-nUr (4) The combined coefficient U is the reciprocal of Rr , or where U - 1/flr . (5) V = combined coefficient to be used with ceiling area. Rt = total resistance of ceiling and roof. Ut, -- coefficient of transmission of ceiling. .. Ur *= coefficient of transmission of roof., n -- ratio of roof area to ceiling'area. * It should be noted that the overall coefficient- U should be multiplied by the ceiling area to determine heat loss, and not / 122 CHAPTER 9 1959 Guide Table 17 .... Effective Resistance of Ventilated Attics*--(Summer Condition)11 PART A. NON-RfflECTfVE SURFACES No Ventilation Natural Ventilation Power Ventilation* Veofffofiost Air temp^ F Sol-air4 temp., F Ventilation rate, cfm/ tq ft 0.1* 0.5 l/U Ceiling resistance, re* 1.0 . 1.5 10 20 10 20 10 20 10 20 10 20 120 1.9 1.9 ' 2.8 8.4 6.3 9.3 9.6 16 11 20 80 140 1.9 1.9 2.8 3.5 6 5 10 9.8 17 12 21 160 1.9 1.9 2.8 3.6 6.7 11 10 18 13 22 120 1.9 1.9 2.5 2.8 4.6 6.7 6.1 10 6.9 13 90 140 1.9 1.9 2.6 3.1 5.2 7.9 7.6 - 12 8-6 15 160 1.9 1.9 2.7 3.4 5.8 9.0 8.5 14 10 17 120 1.9 1.9 2.2 2.3 3.3 4.4 4.0 6.0 4.1 6.9 100 140 1.9 1.9 2.4 2.7 4.2 6.1 5.8 8.7 6.5 10 160 1.9 1.9 2.6 3.2 5.0 7.6 7.2 11 8.3 13 PART B. REFLECTIVE SURFACES' 120 6.5 6.5 8.1 8.8 13 17 17 25 19 30 80 140 6.5 6.5 8.2 9.0 14 18 18 26 20 31 160 6.5 6.5 8.3 9.2 15 18 19 27 21 32 120 6.5 6.5 7.5 8.0 10 13 12 17 13 19 - 90 . 140 6.5 6.5 7.7 8.3 12 15 14 20 16 22 160 6.5 6.5 7.9 8.6 13 16 16 22 IS 25 120 6.5 6.5 7.0 7.4 8.0 10 8.5 12 .8.8 12 100 140 6.5 6.5 7.3 7.8 10 12 11 15 ' 12 16 160 6.5 6.5 7.6 8.2 11 14 13 18 15 20 The term effcctim rtrirtonce b need when there b attic ventilation. A value for no ventilation b alao included. The effective teebtence of the attic may be added to the leebtaMe (1/U) of the (Table IS, Part D) to obtain the effective reebtanee of the combination baaed on sol-air (Chapter U) and room temperature. These raltms apply to wood frame construction with a roof deck and roofing having a conductance at 1J> Btu/(*q ft) (hr) (F dec)- t When attic ventilation meet* the requiremente of Table S in Chapter 10,0.1 cfro/sq ft may be assumed ae the natural rammer ventilation rate for deaign purpoeea. * Bsnistane* t/ntt,abbreviatedr bone (hr) (aqft) (Fdeg) per Btu. DetermineceilingAaistanee from Tables Hand 16, and correct for framing by Figure S. Do not add the effect of a reflective surface facing the attic to the ceiling resistance from Table 16, hrt D, ae it b accounted for in Table 17, Part B. d ftof rarfrae temperature rather than sol-air temperature (see Chapter 13) may be used if 0.29 b subtracted from the attic resistance shown. ' Bssed on sir discharging outward from attic. 1 Surfaces with effective embbvity B cf 0.0S between ceiling joists facing the attic space. by the roof area. Values of Ur and [/. should be calculated using a value of 2.5' (the reciprocal of one-half the air space resistance, 0.80) rather than the conductances of surfaces facing the attic, since the attic is assumed to be equivalent to an air space. . - If the attic contains windows, dormers, and vertical wall spaces, and if their area is small compared to that of the roof, they may be considered part of the roof area. For accuracy, the sum of the coefficients of each individual section, multi plied by its percentage of the total area, should be used as Ur. Where attic wall areas are large or where louvers or vents are used, it is preferable to estimate the attic temperature as illustrated in Chapter 12, and calculate the heat loss through the ceiling by multiplying the value of Ue* for the ceiling by the difference in temperature above and below the ceiling. - BASEMENT FLOOR, BASEMENT WALL, AND CONCRETE SLAB FLOOR COEFFICIENTS The heat transfer through basement walls and floors to the ground is dependent on the temperature difference between the air within and that of the ground, on the material con stituting the wall or floor, and on the conductivity of the sur rounding earth. The conductivity of the earth will vary with local conditions, and is usually unknown. Tests12 at the ASHAE Research Laboratory indicate a beat flow of approxi mately 2.0 Btu per (hr) (sq ft) through an uninsulated con crete basement floor,, with a temperature difference of 20 deg between ground temperature and the air temperature 6 in. above the floor (see Table 18). . For basement walls below grade only, the temperature dif ference for winter design conditions will be greater than for tiie floor. The test results indicate a unit area heat loss, at mid height of the basement wall portion below grade approxi mately twice that of the same floor area. For concrete slab floors laid in contact with the ground at grade level, teste1* indicate that for small floor areas (equal to Table 18 .... Coefficients of Transmission (l/) of Concrete Basement Hoots on Ground with Various Types of Hnish Flooring U = 0.10* Btu per (br) (sq ft) (Fahrenheit degree temperature difference between the ground and the air over the floor). * Since authentic data axe not available, this coefficient ia sometimes used (or " '< floors os (round. For more recent procedures11 refer to National Bursaat tf Standards Report BMS-IQ3. Heat Transmission Coefficients of Building Materials 123 that of a house 25 feet square) the heat loss may be calculated as proportional to the length of exposed edge rather than total area. This amounts to 0.81 Btu per (hr) (linear foot of ex posed edge) (Fahrenheit degree difference between the indoor air temperature and the average outdoor air temperature). It should be noted that this may be appreciably reduced by in sulating under the ground slab, and also along the edges be tween the floor and the abutting walls. See also sections on Basement Temperatures and Heat Loss, and on Floor Heat Loss in Basementless Houses, in Chapter 12. In most calcula tions if the perimeter toss is calculated accurately, no other floor loss need be considered. GLASS AND DOOR COEFFICIENTS The U values for glass sheets and hollow glass block, given in Sections A, B, and C of Table 19, have been computed by methods ind data given in an ASHVE Research Paper.* It is assumed that the surface conductance for convection - loss td the air is 4.0 Btu per (hr) (sq ft) (F deg). It is also as sumed that the glass loses heat by radiation to the ground and to the clear sky, which together have an effective radiat ing temperature below the air temperature. It is therefore necessary to determine, by trial and error, the temperature of the outdoor glass surface such that the sum of the radiation and convection losses equals the heat conducted through the glass section, and equals the heat delivered to the glass from the heated space. This heat flow, divided by the air-to-air temperature.difference, results in a U value that is used in the usual manner. The equivalent surface conductance for radiation and convection combined, based on air-tosurface temperature difference, therefore varies from about 5.5 for single glass to about 6.6 for double glass for exactly the same environmental design conditions. Curtains, draperies, Vene tian blinds, etc., will result in lower glass surface temperatures than when the windows are not covered. It is assumed that the room air temperature equals the aver age temperature of the room surfaces seen by the glass. Special consideration should be given to those cases where the glass sees interior surfaces at temperatures differing greatly from the room air temperature, i.e., such cases as in sun rooms, greenhouses, and some panel heated rooms, or where there is an unusual amount of air motion in the vicinity of the glass. Although based on zero outdoor air, the values change only slightly with different design temperatures, being about 5 percent greater for a 30 F outdoor design temperature. In computing the Table 19 values, consideration of the de pendence of the indoor surface conductances upon tempera ture and direction of heat flow leads to surface conductances averaging about 1.50 for block and vertical glass, and about 1.80 for horizontal glass, as compared to the value of 1.46 used in computing U values given in other tables in this chapter. These values should therefore be used in estimating the temperature at which condensation on glass surfaces will occur. The application factors given in Section D of Table 19 are based upon hot box tests summarized in a research bulletin,14 and are approximate only. In practice, some variation in heat flow through windows having the same ratio of glass to sash area, may be expected because of difference in construction details and in air-space edge effects. The high conductance of aluminum and steel sash must be taken into consideration where excessive amounts of metal sash and frames are in volved. This is particularly important when they are in close proximity to radiation heat sources and are consequently subjected to high differential temperatures. ' Table 19 .... Coefficients of Transmission (U) of Windows, Skylights and Glass Block Walls Coefficients are expressed m Btu par (hour) (square (oof) (Fahrenheit degree difference in temperature between (be air on the two srdci). Those for out door exposure* are bored upon (be foflowing outdoor conditions:' 0 F air temperature, dear skies, no tolar radiation, end 15 mpb outdoor wind rstodty SECTION A--VERTICAL GLASS SHEETS Number of Sheets................... One Two Three Air space, inches............. None X X 1* X X l* Outdoor exposure........ 1.13 0.61)0.55 0.53 0.41 0.360.34 Indoor exposure........... 0.75 0.50 0.46 0.45 0.38 0.33 0.32 SECTION B--HORIZONTAL GLASS SHEETS Heal Row Up Heal Raw Down Number of Sheets.......... One Two One Two Air space, inches . .. Outdoor exposure . None X 1 X o!e3 1.40 0.700.66 None X X Indoor exposure.. 0.96 0.59|0.56 0.56 0.60 0.43 0.39 0.38 SECTION C--WALLS OF HOLLOW GLASS BLOCK Description Outdoor Indoor Exposure Partition 7X.x7X x 3% in. thick with glass fiber di11X ? flX x 3J4 In. thick with glass fiber 0.44 0.36 SECTION 0--APPROXIMATE APPLICATION FACTORS FOR WINDOWS--ML/LT/PIY FLAT GLASS U VALUES BY THESE FACTORS Window Description Single Gloss Double Glass* Windows with Storm Sosh1 Percent Glass* Factor Percent dots* Factor Percent dots* Sheets.......................... 100 1.00 100 1.00 Wood sash.................. 80 0.90 80 0.95 80 0.90 Wood sash.................. 60 0.80 60 0.85 60 0.80 Steel sasb................... 80 1.00 80' 1.20 SO 1.00* Aluminum. ................ 80 1.10 80 1.30 80 1.10 For I in. or (renter. b See Chapter IS. Tables 14 tad 14, (or rammer load. * See Chapter 13, Tables 14,14, and 16, for summer load. 4 From unpublished date recommended by ASHAE Tech. Adv. Comm, on Heat Flow Through Fenestration. * Unit type double glaring (two lights or penes in same opening). . 1 Una with U rallies (or two sheets with 1 in. air speoe. * Based on area of exposed portion of sash; does not include frame or portions of sash concealed by frame. * For metal storm sasb or metal teah with attached storm pane. 124 CHAPTER 9 1959 Guide Heat transmission coefficients for wood doors, with and without tria-gw storm doors are given in Table 20. WIND VELOCITY EFFECT ON U VALUES Tables 5 through 8, 13-A, 14-A, 15, parts of Table 19, and Table 20 show values of U for winter calculations, for an out door wind velocity of 15 mph. Tables 13-B and 14-B show values of U for summer calculations and an outdoor wind velocity of 7.5 mph. Tables 11,12, and 15 show values of V for both winter and summer. Tables 9 through 12 are for in door U values and are based upon still air. All roof coefficient tables also take into account the direction of heat flow. Care must be exercised in selecting the table which applies to the design conditions. Table 21 shows comparative values of U for other wind velocities. When this table is used for summer Table 20 .... Coefficients of Transmission (U) of Solid Wood Doors ' Coeffidmb or* expressed in.Shi p*r (hour) (square foofj (Fahrenheit de gree difference m temperature between the o>> on the two dde), and are bared upon an ovtdde wind velocity of 15 mph. Noond Thickness Actual Thickness u> U* > With Glass Inches Cxpored Door Sform Door* 1 'Hi 0.64 0.37 IK iKs 0.55. 0.34 IK IKe 0.49 0.32 IK 1H 0.48 0.31 2 m 0.43 0.28 2K 2K 0.36 0.26 3 2K 0.31 0.23 * Computed using k -- 1.10 for wood. / -- 1.40, / " 0.0, end 1.03 for sir space. value of 0.85 may be used tor single exposed doors containing thin wood panels or tingle panes of glass, and 0.39 for the same with glass storm doors. * 50 percent glass and thin wood penela. U values, it is necessary to enter the table at 7.5 mph which can be interpolated between 5 and 10 mph. Any value taken from this table should be rounded to two significant figures. Example 8: Find the coefficient of transmission V of a frame wall consisting of stucco, 9$32~in. insulation board sheathing, 2 x 4-in. studs, gypsum lath and plaster, and with 2-in. blanket insulation between studs, for 25 mph wind velocity. Solution: From Table 5, this wall, F37, with no insulation between studs has a value of U = 0.22. From Table 16, Part A, Col. 4, this wall with 2-in. insulation added has a value of V -- 0.084. Entering Table 21 in the 15 mph column, interpolate between 0.080 and 0.090 in 15 mph column and proceed horisontally to the 25 mph column where the U value is found by interpolation to be 0.085. CALCULATING SURFACE TEMPERATURES In many heating and cooling load calculations it is neces sary to determine the inside surface temperature or the tem perature of the surfaces within the structure. As the resistance of any path of heat flow is expressed in Fahrenheit degrees per (Btu)/(hour) (square foot), the resistances through any two paths of heat flow would be proportional to the tempera ture drop through these paths, and can be expressed as fol lows: . Ri m (U - Q Ri " (tt -- O Table 21 .... Conversion table for Wall Coefficient U for Vartan Wind Velocities 15 mph* 0 U for 0 to 30 opb Wind Vetodtiei 5 10 ) 20 25 30 0.050 0.060 0.070 0.080 0.090 0.049 0.059 0.068 0.078 0.087 0.050 0.059 0.069 0.079 0!089 0.050 0.060 0.070 0.080 0.090 0.050 0.060 0.070 0.080 0.090 0.050 0.060 0.070 .0.080 0.091 0.050v 0.000 0.070 0.080 0.091 0.100 0.110 0.130 0.150 0.170 0.096 0.105 0.123 0.141 0.158 0.099 0.108 0.127 0.147 0.166 0.100 0.109 0.129 0.149 0.169 0.100 0.110 0.131 0.151 0.171 0.101 0.111 0.131 0.151 0.172 0.101 0.111 0.131 0.152 0.172 0.190 0.210 0.230 0.250 0.270 0.175 0.192 0.209 0.226 0.241 0.184 0.203 0.222 0.241 0.259 0.188 0.208 0.227 0.247 .0.266 0.191 0.212 0.232 0.252 0.273 0.192 0.213 0.233 0.253 0.274 0.193 0.213 0.234 0.254 0.275 0.290 0.310 0.330 0.350 0.370 0.257 0.273 0.288 0.303 0.318 0.278 0.296 0.314 0.332 0.350 0.286 0.305 0.324 0.344 0.363 0.293 0.313 0.333 0.354 0.375 0.295 0.315 0.336 0.357 . 0.378 0.296 0.317 0.338 0.359 0.380 0.390 0.410 0.430 6.450 0.500 0.333 0.347 0.362 0.376 0.410 0.368 0.385 0.403 0.420 0.464 0.382 0.402 0.421 0.439 0.487 0.395 0.4160.436 0.457 0.509 0.399 0.420 0.441 0.462 0.514 0.401 0.422 0.444 0.465 0.518 0*600 0.700 0.800 0.900 1.000 0.474 0.535 0.592 0.645 0.695 0.548 0.631 0.711 0.789 0.865 0.581 0.675 0.766 0.858 0.949 0.612 0.716 0.821 0.927 1.034 0.620 0.728 0.836 0.946 1.058 0.626 0.736 0.847 0.960 1.075 1.100 1.200 1.300 0.742 0.786 0.828 0.939 1.010 1.080 1.039 1.129 1.217 1.142 1.250 1.359 1.170 1.285 1.400 1.192 1.318 1.430 V in first column b from previous table* a * calculated for IS mph wind where '. Ri - the resistance from the indoor air to any point in the structure at which the temperature is to be deter mined. ' Ri = the overall resistance of the wall from indoor air to outdoor air. " t{ " indoor air temperature. = temperature to be determined. f# outdoor air temperature. * Example 9: Determine the inside surface temperature for a wall having an overall coefficient of heat transmission U =* Heat Transmission Coefficients of Building Materials 125 0.25, indoor air temperature 70 F, and outdoor air temperature --20 F. Solution: - R = MSi = 1/1.46 - 0.684 Rt = 1/C/ - 1/0.25 - 4.00 Then, by Equation 6 0.684 70 -5, 4-00 ** 70 -- (-20) 4 = 54.6 F Example 10: Determine the temperature of the bottom of a 4-in. insulated concrete roof slab to which has been glued Jr^-'in. acoustical tile (C * 0.84) as the interior finish. The roof-ceiling overall coefficient of heat transmission U is 0.14 for beat flow up. The indoor air temperature is assumed to be 70 F and the outdoor air temperature --20 F. Solution: letin No. 3, p. 40, also published in ASHVE Transactions, Vol. 53, 1947, p. 245). G. V. Parmelee and W. W. Aubele; ASHVE Research Report No. 1399--Heat flow through unshaded glass: Design data for load calculations (ASHVE Transactions, Vol. 56, 1950, p. 371). * H. E. Robinson, F. J. Powlitch, and R. S. Dill: The Thermal Insulating 'Value of Airspaces (Housing and Home Finance Agency, Housing Research Paper No. 32, U. S. Government Printing Office, 1954). * G. B. Wilkes, F. G. Hechler, and E. R. Queer: Thermal test coefficients of aluminum insulation for buildings (ASHAE Transactions, Vol. 46, 1940, p. 109). " F. A. Joy: Improving attic space insulating values (ASHAE Journal Section, Heating, Piping and Air Condi tioning, January 1958, p. 223). 11 F. C. Houghten, S. I. Taimuty, Carl Gutberlet, and C. J. Brown: ASHVE Research Report No. 1213--Heat loss through basement walls and floors (ASHVE Transactions, Vol. 48, 1942, p.369). 11 R. S. Dill, W. C. Robinson, and H. E. Robinson: Measure ments of Heat Losses from Slab Floors (National Bureau of Standards, Building Materials and Structures Report BMS 103). - u G. V. Parmelee:Heat Transmission through Glass (ASHVE Research Bulletin No. 1, July 1947). Then, by Equation 6 1-80 70 - t, 7.14 " 70 - (-20) 5, = 47.3 F The concrete surface temperature is of interest since refer ence to a psychrometric chart or table will show that moisture condensation could occur on this surface under the above conditions (47.310 if the relative humidity in the room ex ceeds 44 percent. Additional roof insulation should be con sidered above the slab to avoid condensation at this point if higher relative humidities in the room are anticipated. The same procedure can be used for determining the tem perature it any point within the structure. A chart for determining inside wall surface temperature is given in Fig. 13 of Chapter 30, Panel Heating. REFERENCES 1 Standard Method of Test for Thermal Conductivity by Means of the Guarded Rot Plate, sponsored by ASHVE, ASTM, ASRE, and NRC, and approved as a tentative code by ASHVE and ASTM in 1942 (ASTM designation.C-177-45, Approved, 1945). * F. B. Rowley and A. B. Algren: Heat Transmission Through Building Materials (University of Minnesota, Engineering Ex periment Station Bulletin No. 8, p. 11). * M. S. Kersten: Thermal Properties of Soils (University of Minnesota, Engineering Experiment Station Bulletin No. 28, June 1949). 4 G. B. Wilkes and C. M. F. Peterson: Radiation and convec tion from surfaces in various positions (ASHVE TransacAcnoNS, Vol. 44, 1938, p. 513). * B. F. Raber and F. W. Hutchinson: Radiation corrections for'basic constants used in the design of all types of beating systems (ASHVE Transactions, Vol. 51,1945, p. 213). * F. B. Rowley, A. B. Algren, and J. L. Blackshaw: ASHVE Research Report No. 869--Surface conductances as affected by air velocity, temperature and character of surface (ASHVE Transactions, Vol. 36, 1930, p. 444). 7 G. V. Parmelee and R. G. Huebscber: Forced Convection Heat Transfer from Flat Surfaces (ASHVE Research Butr- BIBLIOGRAPHY ASHVE Research Reports: No. 852--F. B. Rowley, A. B. Algren, and J. L. Blackshaw: Effects of air velocities an surface coefficients (ASHVE Trans- . actions, Vol. 36, 1930, p. 123). No. 895--F. C. Houghten and Paul McDermott: Wind veloci ties gradients near a surface and their effect on film conduct ance (ASHVE Transactions, Vol. 37,1931, p. 301). No. 914--F. B. Rowley and W. A. Eckley: Surface coefficients as affected by direction of wind (ASHVE Transactions, Vol. 38, 1932, p. 33). No. 9^S--F. C. Houghten and Cart Gutberlet: Conductivity of conc.ete (ASHVE Transactions, Vol. 38, 1932, p. 47). No. 964--F. B. Rowley: The heat conductivity of wood at climatic temperature differences (ASHVE Transactions, Vol. 39, 1933, p. 329). No. 966--F. B. Rowley: Insulating value of bright metallic surfaces (ASHVE Transactions, Vol. 40, 1934, p. 413). No. 1026--F. B. Rowley, A. B. Algren, and Clifford Carlson: Thermal properties of concrete construction (ASHVE Trans actions, Vol. 42, 1936, p. 33). No. 1048--F. B. Rowley, A. B. Algren, and Robert Lander: Thermal properties of concrete construction (ASHVE Trans actions, Vol. 43, 1937, p. 33). No. 1351--G. V. Parmelee and W. W. Aubele: Overall coeffi cients for flat glass determined under natural weather condi tions (ASHVE Transactions, Vol. 55, 1949, p. 39). G. B. Wilkes and C. M. F. Peterson: Radiation and convec tion across air spaces in frame construction (ASHVE Trans actions, Vol. 43, 1937, p. 351). L. W. Schad: Insulating effect of successive air space bounded by bright metallic surfaces (ASHVE Transactions, Vol. 37, 1931, p. 285). J. D. MacLean: Thermal conductivity of wood (ASHVE Transactions, Vol. 47, 1941, p. 323). G. B. Wilkes and C. O. Wood: The specific heat of thermal insulating materials (ASHVE Transactions, Vol. 48, 1942, p. 493). D. B. Anderson: Heat loss studies in four identical buildings to determine the effect of insulation (ASHVE Transactions, Vol. 48, 1942, p. 471). 126 CHAPTER 9 1959 Guide . T. D. Phillips: Effect of Ceiling Insulation upon Summer Comfort {National Bureau of Standards Report BMS52, July 1, 1940). L. V. Teesdaie: Thermal Insulation Made of Wood-Base Materials, Its Application and Use tn Houses {U. S. Forest Products Laboratory Report No. R1740, October 1949). F. B. Rowley and A. B. Algren: Heal Transmission through Building Materials (University of Minnesota, Engineering Ex periment Station Bulletin No. 8). Paul D. Close: Building Insulation (American Technical Society, Chicago, 1951, 4th ed.). \ CHAPTER 10 MOISTURE IN BUILDING CONSTRUCTION Properties of Water in Air; Water in Building Materials; Vapor Transmission; Permeance and Testing; Viable Condensation; Concealed Condensation in Heated Buildings; Control of Concealed Condensation; Condensation in Cooled Structures. THE behavior of moisture is too often overlooked or given humidity. The vapor pressure of the water present in the air, scant attention in the Hpsign and construction of build although not shown on the chart, can be calculated readily ings. It is present as a vapor in all air and as adsorbed moisfrom the vapor pressure at saturation and the relative hu ture in most building materials. It may be present also at midity, since relative humidity is very nearly equal to the times in the free liquid state or as ice, in the solid state, within ratio of the actual vapor pressure to the saturation pressure the range of temperatures encountered in many buildings. at the existing temperature. Problems involving moisture may arise from changes in mois - The . increasing relative humidity accompanying cooling ture content, from the presence of excessive moisture, or from from the condition represented by A on the chart to point B effects associated with its changes in state. can readily be followed. At B, however, at 44.6 F, the relative Of particular interest is the change from the vapor to the humidity becomes 100 percent, and the air-vapor mixture is liquid or solid state, known as condensation. This may be said to be saturated. The temperature at which this particu associated with a reduction of temperature with time, or lar air-vapor mixture, upon cooling, becomes saturated is its may occur as a result of migration of water vapor to regions dew-point temperature. Upon further cooling, to 35 F, the of lower temperature. Moisture problems involving condensa original amount of water vapor can no longer be retained and tion are therefore most likely to occur in buildings in any is reduced, in this case, to the condition represented by C, climate in which there is a source of water vaponat tempera from 0.0633 lb per lb dry air to 0.0427 lb per lb dry air. The tures above normal, or in cooled structures, and in buildings process ABC is typical of that which an air-vapor mixture in cold climates. experiences when it comes in contact with a cool window ' Moisture problems in residences occur in winter and be surface. Cooling from B to C results in visible condensation come increasingly important as homes are built smaller and on the glass surface. If the point C were below 32 F, the con tighter. Water vapor originates from such necessary living densation would be in the form of frost. requirements as cooking, laundering, bathing, and the breath Once the temperature drops below the dew point, or frost ing and perspiration of people. In a typical family of four, point if below 32 F, the vapor pressure at the condensing the average daily production of water vapor from these sources surface is also reduced, thereby establishing a gradient- of may be as much as 25 lb, and may be much greater where such vapor pressure from the room air to the window surface. This appliances as humidifiers, automatic washers, and. dryers gradient will operate, in conjunction with the convective ac are used.1 Another large source of water vapor is sometimes tion within the room, to move water vapor continuously to the bare earth in a crawl space or basement. All this water the window surface to be condensed, bo long as the concentra vapor must escape from the dwelling. r tion of water vapor in the room is maintained. PROPERTIES OF WATER VAPOR IN AIR A common winter process is that shown by DE, showing air at 20 F, saturated, being heated to 70 F with a resulting Water vapor in air is a gas which occupies all the space, large decrease in relative humidity. This explains, in part, along with the air present. In many ways, the water vapor can act independently of the air,, since in general its proper ties do not depend on the presence of the air. It exerts its own vapor pressure, and can move about through air in a space, or move through materials under differences in its own vapor pressure, independently of the air. However, when the air is moved suddenly or is heated or cooled, the water vapor pres ent is similarly affected, so that it is usually necessary to con sider it as a part of an air-vapor mixture. The properties of mixtures of air and water vapor are rela tively well known and are discussed in Chapter 3, Thermo dynamics. Changes in these properties with heating and cool ing can be followed readily with the aid of a psychrometric chart, shown in outline in Fig. 1. The saturation line repre sents the limiting concentrations of water vapor which can exist as vapor at various temperatures. A common condition inside buildings, 70 F and 40 percent Fig. 1 .... Two Typical Heating and Cooling relative humidity, is represented by point A. This is a condi Processes in Air within Buildings Shown tion of partial saturation; i.e., less than 100 percent relative cwvASHAE Psychrometric Chart !5 si i !l :t 11 .s 1 ; ji ]\ !: :-l '\i - ;5 : 'i 128 CHAPTER 10 1959 Guide the greatly reduced relative humidities experienced in houses remain more or less stationary and will increase the conduc in extreme cold weather, when cold outdoor air enters die tivity largely by adding to the path available for heat flow. house and is heated. On this basis, the effect of moisture on heat flow can be ac WATER IN BUILDING MATERIALS counted for quite simply by the use of suitable coefficients of conductivity in the usual heat-flow equations. The data The surfaces of most common materials have an affinity, presented in Chapter 9 on moist soils are of this type. for water molecules. Molecular forces of attraction will hold, '' Evidence to date indicates, however, that in porous ma water molecules to the surface, but decrease very rapidly terials partially saturated with water there is likely to be a with increase in distance of molecular proportions. The film migration of moisture to the cold side under the influence of thickness and therefore the amount of water held in equilib the temperature gradient. This can occur by a process of rium with the surrounding atmosphere is roughly proportional - evaporation, vapor flow, and condensation within the mato relative humidity. Surface films of water molecules, at low' terial, a substantial amount of heat being transferred as humidities, may be only one molecule thick; at moderate latent heat of the vapor, particularly in the case of open humidities poly-molecular films may be established, while - ' fibrous materials. The transmission of heat through moist at humidities very close to 100 percent, the films become so materials becomes complex whenever conditions are such as thick, relatively, that small pores may become filled and to produce any appreciable migration of the moisture, and, larger capillaries may be partially filled. At saturation condi tions all voids in the material may be completely filled. consequently, calculations by the usual heat-flow theory alone, are an approximation. ' * ' Some materials such as silica gel, alumina and most natural The usual approach to the calculation of moisture migra fibrous materials present very large effective surfaces to the tion has been to consider the flow as hydraulic, under the water molecules, so that the amount of water held on the effective surface in these materials may be relatively large, influence of hydrostatic forces when the materials are satu rated, and as a vapor flow produced by vapor pressure dif even at moderate humidities. These are said to be hygroscopic. ferences in unsaturated materials. These simple concepts Other materials, such as most metals, not penetrated by the might be adequate were it not for the fact that there are inter water molecules, present relatively small surfaces and so may actions between water molecules and the material through take only minute quantities of water, except when wetted directly by liquid. ` which they are passing, as already mentioned. Further com plications may be introduced by the presence of salts and Substances having a great affinity for water, and their use as dehumidifying agents, are described in Chapter 42. Data electrical potentials. It is now recognized that the migration of moisture under on tire moisture contents of various common materials in equilibrium with the atmosphere at various relative humidities are given in Table 2 of Chapter 50, and equilibrium moisture content is further discussed in Chapter 53 oh Industrial Drying Systems. conditions of partial saturation in a material having an affin ity for water actually occurs as a kind of series-parallel flow of vapor and liquid, with the liquid phase having more and more influence as the moisture content, or the degree of satura tion, increases. The two kinds of flow cannot be separated Significant dimensional changes take place in many ma since they are closely coupled everywhere along the flow path terials used in buildings, with change in moisture' content. by evaporation and condensation. Enough is already known The best known are those'which take place in wood, of the to indicate that the isothermal or constant temperature case order of 0.1, 2, and 4 percent in the longitudinal, radial and of yapor flow under a vapor-pressure gradient is much more tangential directions, respectively, on. a change from air dry manageable than the cases in which there are both tempera at 12 to 15 percent moisture content to oven dry conditions. Most wood-fiber products, including papers, will exhibit mois ture and vapor-pressure gradients. Cases of combined heat and moisture flow are now known to be extremely complicated ture expansion consistent with the basic wood properties to a and it is quite clear that when both are occurring, neither degree dependent on the fiber orientation and arrangement. one can be adequately dealt with independently of the other. Data on wood are available in publications on wood tech . No adequate way of handling the general case theoretically nology. Almost all plant and animal fibers experience ap has yet been found, despite efforts being made in many preciable moisture changes with changing relative humidity laboratories. The bibliography at the end of this chapter and undergo substantial dimensional changes of the same includes some of the more important papers on this subject. order as those in wood. Less generally recognised are the di A relatively ample equation for the calculation of water- mensional changes that ran occur in masonry materials as a vapor flow based upon the concept of vapor pressure alone result of changes in moisture content. ' as the driving force, has been in use for a number of years. Water is either an essential or a contributory factor in al It can be applied without great difficulty to cases where uni most all cases of breakdown of building materials resulting form temperatures or only small temperature gradients exist, from chemiral changes such as the rusting of steel, physical and to cases of low or moderate relative humidity. It has also . changes such as the spalling of masonry by frost action, or been shown to be useful in other cases, provided that the biological processes such as the rotting of wood. The control proper values representative of the conditions to which it is of water in building constructions may be necessary to ensure being applied can be found for the flow coefficient to be used adequate service from the materials involved. in the calculations. The complications inherent in the com Condensation of water vapor, although not the only means ' bined mechanisms of heat and moisture flow are not ade by which wetting may be brought about, is nevertheless a quately covered by the variables used in the equation, but roost insidious one, particularly in respect to freeze-thaw appear in the determination of suitable values of the flow breakdown, since from its nature it is most likely to occur at coefficient, which, however, may vary greatly for any one points of low temperature at which there may later be risk of material, depending on the conditions of flow. freezing while the material remains in a saturated condition. Moisture in building materials may have a marked effect VAPOR TRANSMISSION THROUGH MATERIALS upon the transmission of heat through them. It has been com The equation presently used in calculating water-vapor monly assumed that moisture when present in a material will transmission through materials is based on a form' of Fick's Moisture in Building Construction 129 Law, and is as follows: dp (1) where te = weight of vapor transmitted through a unit area in unit time. p = vapor pressure. * " distance along the flow path, and hence: ' dp -- vapor pressure gradient. dx p -- permeability. . The close parallel with Fourier's equation for heat flow will be noted. The actual transmission of vapor through a ma terial is extremely complex, so that the coefficient, p, is not a ample one but is actually a function of relative humidity and temperature, and may vary along the flow path through the material in question.* Integrating Equation 1 from x = 0 to x = l and from pi to pi, and rearranging, the following is obtained: where l " length of flow path (or thickness of material). If Equation 1 had been integrated, assuming the coefficient p to be independent of vapor pressure (and temperature) along the flow path, Equation 4 would have been obtained, but with M -replaced by p. The coefficient is therefore an average permeability coefficient applicable to the varying conditions along the flow path of length l, while the coefficient p is tiie spot or differential permeability. - Equation 4 may be rewritten and units assigned: . . A? W pA6 -- (5) where, W = total weight of vapor transmitted, grains. A -- area of cross-section of the flow path, square feet. $. " time during which the transmission occurred, hours.' Ap -- difference of vapor pressure between ends of the flow path, inches of mercury. I -- length of flow path, (or thickness of specimen), inches. The basic units given are those now favored by the build ing industry. The permeability p or p is therefore expressed in a unit of grains-inches per (square foot) (hour) (inch of mercury vapor pressure difference). ^ ^ stated or implied thickness other than the unit thickness to which p or p refer, use may be made of the permeance co efficient M, where M = p/l. The designation perm for the unit of permeance is now widely used, and is a convenient substitute for the unit, 1 grain per (square foot) (hour) (inch of mercury vapor pressure difference).* The corresponding unit of permeability is perm-inch, since it is the permeance of unit thickness. The corresponding flow equation is: W = UAOAp (6) Resistance to vapor flow provided by a sheet or board is the reciprocal of the permeance, and correspondingly, the over-all vapor resistance of an assembly (like a wall) of ma terials in series is the sum of the resistances of its component parts. The over-all permeance of the assembly may be found from the permeances of the individual components4, * in a mannpr paralleling that used in calculating the over-all co efficient of thermal conductivity from the individual con ductances: ---- X ---- X --- ... X ----- Mx Ut Aft . AT. This simple theory for vapor flow, as in the case of the cor responding simple heat-flow theory, assumes conditions of unidirectional, steady-state flow. Useful calculations can be made for an assembly or sub-assembly for which the inflow and outflow of vapor are equal (a condition at which no con densation occurs) if a permeance applicable to actual condi tions ran be assigned to each component part. Over-all per meances, vapor pressures and vapor flow can be calculated, and in conjunction with thermal calculations, relative hu midities ran be determined, and the imminence of condensa tion predicted. (See Example l, and Fig. 2. See also Chapter 13, Cooling Load, for use of vapor-flow calculations.) Example t: A wood frame wal] is exposed to indoor conditions 70 F ana 60 percent relative humidity (0.37 in. Hg vapor pres sure) and outdoor conditions 0 F and 80 percent relative PLASTER MINERAL WOOL SKEATHOM ON LATH BETWEEN STUDS% RAPES a StOOM * TO i SO S so C 40 < 30 at to iS rSATURATION \ APOR PRESSURES S "> S -60 M -SO I *0 1 VAPOR PRESSURES FOR i j plow ccwnNuITT \ . VAPOR PRESSURES WITH N&ATTON AT X*X S -so --hv a .zo / ' Av-------- 0 >10 1o % Hg. 2 .... Temperatures and Vapor Pressures under' Vapor Row Conditions in the Insulated Frame Wall of Example 1. - 130 CHAPTER 10 1959 Guide humidity (0.03 id. Hg vapor pressure). The wall consists of painted plaster on gypsum lath on the inside over 2 X 4 in. studs, mineral wool fill between studs, 1 in. wood exterior sheathing, paper, and pine lap siding. Check for possible condensation. To simplify the example, consider the paint, piaster, and lath as a single element having a permeance m = 1.0 perms and a thermalconductance C = 2.4, and the exterior sheathing, paper, siding, and paint as another single element for which Af " 2.0 perms ana C " 0.50. From Table 1 the value for the permeability of mineral wool fill may be found as -- 116 rm-inches. The thermal conductivity for mineral wool - 0.27. ' Solution: In this particular wall, insulated, and with moder ate warm-side relative humidities, condensation is unlikely to occur until the sheathing is reached. To check directly for condensation on the warm side of the exterior sheathing (des ignated as plane X -- X in Fig. 2 for convenient reference) proceed as follows: Calculate according to the method of Chapter 9 the tempera ture at plane X -- XT This is found to be 9 F. The saturation vapor pressure at this temperature is 0.06 in Hg. If condensa tion is imminent or occurring at X -- X, the vapor pressure there will be 0.06 in. Hg. Calculate the permeance for the portion of the wall from the warm side to X -- X, and the vapor flow rate to X -- X as follows: Permeance of wall to X -- X - -------- --------- = 0.97 perms J_ 3.625 1.0 + 116 Vapor pressure drop to X -- X - 0.37 -- 0.06 * 0.31 in. Hg. Vapor flow to X -- X -- 0.97 X 0.31 = 0.30 grains per (sq ft) (hr). Calculate the vapor flow rate from X -- X to outdoors as follows: Permeance of wall from X -- X to outdoors -- 2.0 perms. Vapor pressure drop from X -- X to outdoors = 0.06 - 0.03 = 0.03 in. Hg. Vapor flow rate to outdoors = 2.0 X 0.03 - 0.06 grains per (sqfi)(hr). - It is apparent that continuity of vapor flow is not possible, since at the highest vapor pressure at X -- X permitted by the temperature, there is indicated a greater flow to plane X -- X than from it to outdoors. Condensation is indicated at a rate of 0.30 -- 0.06 = 0.24 grains per (sq ft) (hr). Whether this condensation rate will be serious must still be decided, since it might readily be absorbed by the sheathing dunng the condensation pericxi without excessive wetting. When the temperature at A -- X is below freesing, as in ttus case, the condensation will be in the form of frost which may. accumulate until released over a short period upon a rise in outdoor temperature. Condensation will be reduced or avoided if the permeance of the warm side of the wall can be reduced so that the flow to X -- X is limited to 0.06 groins per (sq ft) (hr). Permeance required for this is t-z=--" 0.19 perms or less. A more OSSi -- U.Ub resistant paint film on the plaster, reducing the paint-plasterlath permeance to 0.19 perms would accomplish this. When the critical plane for condensation is unknown, or for a more informative, graphical representation of the situation throughout the wall, temperatures and vapor pressures may be calculated and plotted as in Fig. 2. The vapor pressures throughout the wall, for continuity of flow, are calculated in a manner similar to the temperatures; the external vapor pressures are given, and the vapor pressure drops across each element are taken in proportion to resistance to vapor flow. The curve for saturation vapor pressures at the various temperatures throughout the wail is also shown in Fig. 2 and is seen to fall below the curve for vapor pressures with con tinuity of flow, toward the outer portions of the wall. This indicates that with the given temperatures and vapor pres sures, continuity of flow 13 not possible and that condensation will occur. Condensation on the sheathing is indicated as a definite possibility, and the new vapor-pressure curve be constructed for this condition, as shown. This new curve does not rise above the saturatiOD-vapor-pressure curve, thereby confirming that the critical plane for condensation was cor rectly assumed. With the vapor pressures thus established, the relative humidities may oe found, by reference to the saturation vapor pressures. The permeances originally assigned to the various elements may then be re-examined m the light of the service conditions of temperatures and relative humidities indicated, and the analysis repeated, if necessary, using more appropriate permeance values. In a more detailed analysis, individual values might be assigned to the elements forming the outer portion of the wall which is here dealt with as a composite, homogeneous element. The transmission of water vapor as outlined is based on the assumption of a diffusion process. The possibility of vapor being transferred as part of a moving air stream has thus far been ignored, except in Example 1 in which it is implied that the air circulation on either side of the wall will be sufficient to eliminate surface-film resistances to vapor flow. Differences in total pressure of the air may result in a transfer of vapor with air, augmenting and at times over-riding the effects of the flow produced by vapor-pressure gradients alone. This can be particularly important in the transfer of vapor through cracks and pinholes or through air-permeable building con structions. Similar effects can be obtained with air-permeable materials themselves.' ' . This means of vapor transfer is similar to that of transfer of heat by air leakage in and through building constructions, and requires, for purposes of calculation, information on the nature and amount of the air leakage. It will seldom be im portant in constructions without air spaces and having parged or plastered surfaces. It may, however, be an important means of vapor transfer through constructions lacking in air tightness, and may contribute to condensation difficulties, since the mechanism of condensation is not dependent upon the way in which the vapor is transferred. ' PERMEANCE AND TESTING ^The simplest method of finding the permeance of a speci men is to seal it over the top of a cup containing desiccant or water, placing it in a controlled atmosphere, and weighing it periodically. The steady rate of weight gain or loss is nor mally tiie water vapor transfer. When the cup contains a desiccant the procedure is called the dry-cup method and when the cup contains water, the wet-cup method. Usually the sur rounding atmosphere is held at 50 percent relative humidity, thus providing, in either method, substantially the same dif ference of vapor pressure, but the results obtained by the two methods for the same specimens are likely to be much differ ent, the wet-cup method producing the higher values. The relationship between these values can best be understood by reference to Fig. 3, which shows a typical variation of spot permeability with relative humidity at one particular tem perature (isothermal conditions) for a material such as wood. The vapor permeability is shown to vary only moderately at low humidities, but to increase at an increasing rate as higher humidities are reached. The dry-cup test of t-hU material carried out with 0 percent relative humidity one side and 50 percent on the other, will experience throughout its thickness, because of the variation in relative humidity, a variation in spot permeability. The average permeability , is by definition (Equation 3), given by f and since at a fixed tem- Jh ~ Pt perature there is a linear relationship between vapor pressure and relative humidity, this expression can be seen to cor respond to the mean height of the area under the spot per- Moisture in Building Construction 131 Material Table I____Permeance and Permeability of Materials to Water Vapor Perm* one* Purs % ftHt-KHi Method! Eef.t PfOfPerm Methodf Ala (still) Insulation Cellular glass Corkboard Structural Insulating Board (Vegetable, uneoated) Mineral Wool (unprotected) 120* 0.0" 1.1-2.6* 9.6* 20-50- 116* 92-73 75-0 100-45 40-x 100-30 Intebiob Finish Plaster on wood lath 11 100-30 Plaster on metal lath--X in- 15 40-x Plaster on olaiQ gypsum lath 20 40-85 b d d w t w w 4 Wood Sugar Pine 0.4-6.4' Plywood (Exterior type 3 ply 0.72 5 D.F.), k in Plywood (Interior type 3 ply D.F.), X in. Masonbt Concrete (1:2:4 Mix) Concrete (8 in. cored block wall, limestone agrgt.) Brick wall--with mortar--4 in Tile wall--with mortar--4 in. S.2* 2.4 0.8 0.12 100-45 79-68 50-x 50-x Gypsum wall board--plain-- H ininsulating wail board (un- coated)--X ' 50 50-90 50-20 40-x V t 15 9 Penaeonce-Perax dry cup Paint--2 coats Asphaltic paint on plywood Aluminum in varnish on wood Enamels, brushed on smooth 0.4 0.3-0.5 0.5-1.5 100-30 95-0 92-0 w d b Primers or Scalers on insulatine wall board Various Primer* + 1 coat flat paint on plaster Flat paint (alone) on insulat- ing wall board Water Emulsion on insulating wall board 0.9-2.1 1.6-3. 4 30.-85. Paint--Exterior, 3 coats White lead <fc oil prepared pain' 0.3-1.0 on wood siding I 1White lead-zinc oxide A linseed oil on wood 0.9 40-x 40-x 40-x 40-x -- 5(H) 195-0 d d **BtJlLDINQ Papebs and 8 Felts . Duplex sheet, asphalt lami nae, aluminumJail one side Saturated and coated felt 9 ' heavy roll roofing Kraft and asphalt laminae. Reinforced 30-120-30 Insulation back up, asphalt- sat., one side glossy Asphalt-saturated and coated sheathing paper Asphalt-saturated sheathing paper ' 15-pound asphalt felt 15 15-pound tar felt Single sheet Kraft, double infused 0.002 0.176 0.05 0.24 0.3 1.8 0.4 0.6-4.2 0.3 0.6 3.3 20.2 1.0 4.0 30.8 5.6 18.2 * These boldisee v|ue* tn permeability in perm-inches. Description is a guide only, end doe* nos insure pwmennee. _ _l_e_t_b_o_d_s__: _d--__d_ry ,,cap; w wejrdt cap; t--two temperatures^; b--sppeeecaiasl ceeelll;lj*j 7"*" velocity both sides; 4--avenge of four methods. . ,,MW.. .. ) Befeences. No. 9also includes BuSlcriaa 23and tSof the Engineering Experiment Station, Umvenrty of Minnesota. No- 1A indudes data to be published by the Eofineerins Experiment Station, Pennsylvania State Coiiegr meability curve, between the appropriate relative humidity limits. The average permeability as found for the dry-cup conditions should therefore have the value pi. Similarly for the wet-cup test between 50 percent and 100 percent rela tive humidity, the value shouldbe pt. It is not uncommon for these values for wood and wood-fiber materials to be in the ratio of 1 to 3, or higher. (See Table 1.) ' The average permeability p for any other relative humidities at a particular temperature is given by the mean height of the area under the curve of spot permeability for the material at that temperature, between the appropriate limits of rela tive humidity. Only average permeabilities (or permeances) are measurable directly in practical teste. However, if several average permeabilities at different relative humidities are known, and can be plotted as for the wet-cup and dry-cup teste shown in Fig. 3, it is possible to construct, by trial and error, a spot permeability curve which will satisfy the condi tion that the average height of the curve between the ap propriate limits for each test must equal the value found in each test. Separate curves are required for each temperature so that a large number of permeance cup teste would be re quired to cover a range of conditions of both temperature and humidity. , Experience to date shows that the effect of temperature is quite moderate and, for some purposes, differences in tempera ture at which tests are run may be ignored. Corrections for temperature have been made with some success in the case of certain materials by the use of an equation based on activa tion energy7 which states: - where, in appropriate unite, -- permeability at T *" . R -- gas constant. . E - activation energy. e -- Naperian base of logarithms " 2.718. T = absolute temperature. Applications of this equation may be limited to materials such as resins, rubbers, and polymers in which the water enter and move through the molecular structure by a process known as activated diffusion; It may serve also as a useful approximation in other cases. By use of Equation 8, spot permeability curves for a variety of temperatures can be constnicted from a curve for one tem perature, provided only that two teste at different tempera tures can be run, from which E, the activation energy, can be evaluated. In this way it becomes possible to describe the permeability of a material with reasonable completeness from 132 CHAPTER 10 1959 Guide the results of as few as five single tests at carefully selected conditions. No method has yet been found, other than by direct testing for a particular set of conditions, of predicting the effective permeabilities for conditions of temperature gradient alnng with a humidity (or vapor-pressure) gradient, from data ob tained under other conditions, even though this is the general situation in practice. A very considerable amount of informa tion is available on the permeances and permeabilities of various materials, but these are frequently obtained at dif ferent conditions so that the results cannot be compared directly, nor do they often give a coverage of a range of con ditions to permit construction of basic curves of spot per meability or permeance. Since dry-cup and wet-cup tests are much easier to carry out than tests at intermediate humidities, many of the data available have been obtained in this way. In the absence of of weight transmitted per (unit area) (unit time). Such data may be called water-vapor transmission data or WVT data And values are either high or low depending on the difference of vapor pressure chosen for the test. When this difference is known, WVT data can be converted to permeance, care being taken, if conversion of the basic unite (weight, area and time) is also required. The following formula applies: where WVT rating Permeance -------------------- ap ' . (9) - WVT rating = weight of vapor transmitted, grains per ' (sq ft) (hoar). ` Ap ** vapor-pressure difference in the test, in - inches of mercury. Permeance is expressed in perms. Table 2 presents the conversion factors applicable to the commonly used unite and test methods. Table 1 presents some data on typical building materials showing, in each case, the source and method and, where applicable, the thicknaa^ tested. Water-proofed building papers are listed in Federal Spe cifications UU-P-147,'May 24,1948, according to water-vapor resistance required as: fig. 3 .... Relation between Dry and Wet Cup Tests - and the Spot Permeability for a Material . such as Wood data obtained from tests duplicating the conditions of tem perature and relative humidity in service, the permeance of a piece of material may be judged adequately for many pur poses if it is tested by both dry and wet methods. It is obvious that any statement of permeance of a specimen should include tire conditions of test. - Method of test E96-53T of the American Society for Testing Materials describes procedures for testing for water-vapor transmission of materials in sheet form under five different test conditions. These include the dry-cup and wet-cup meth ods, based on 50 percent relative humidity outside the cup, at either 73.4 or 90 F, and a fifth condition at an elevated temperature of 100 F with relative humidities of 0 and 90 percent on either side of the sheet. Standard T448m-49 of the Technical Association of the Pulp and Paper Industry covers the determination of water-vapor transmission of paper and paperboard, and calls for the dry-cup method at 73.4 F, based on 50 percent relative humidity outside the cup. ASTM Standard C355-54T covers tentative methods of test for water vapor transmission of materials used in building con struction. Unfortunately, there is no general agreement as yet to re port results as coefficients of permeance, or of permeability where appropriate, os adopted in this chapter, or to use the same basic unite. Test data are frequently reported in terms Class A. For uses where a high degree of water-vapor resistance is required. Class B. For uses where a lower degree of water-vapor resistance and of water resistance is required. Class C. For uses where a moderate degree of water-resist ance is required. Class D. For uses where low resistance to water vapor is . required. It may be noted that a paper may be water-proof, i.e. possess water resistance, and still have low water-vapor resistance. Detail requirements in these specifications are given as follows, the specified WVT Test being a dry method at 73 F. Clast A paper shall have a minimum tensile strength in each direction of either 351b per inch width, or 20 lb per inch width, as specified in the invitatioa for bids. Paper of both strengths shall have a minimum water resistance of 24 hr, and a maximum water vapor permeability (WVT) of 4 grams per (square meter) (24 hr) i.e. 0.576 perm. Clast B paper shall have-a minimum tensile strength in each direction of either 35 lb per inch width, or 20 lb per inch width, as specified in the invitation for bids. Paper of both strengths snail have a minimum water resistance of 16 hr, and a maximum water-vapor permeability (WVT) of 6 grams per (square meter) (24 hr) i.e. 0.804 perm. Clast C paper shall have a minimum tensile strength in each direction of either 35 lb per inch width, or 20 lb per inch width, as specified in the invitation for bids. Paper ofboth strengths shall have a minimum water resistance of 8 hr. Clast D paper shall have a minimum tensile strength in each direction of 20 lb per inch width. The paper shall have a mini mum water resistance of 10 min., a minimum water-vapor permeability (WVT) of 35 grams per (square meter) (24 hr) i.e. 5.04 perms. VISIBLE CONDENSATION Just as moisture collects on the outer surface of a ghuw of cold water, so does it also condense-on other cold materials. In winter, visible condensation may collect on cold closet walls and attic roofs and is commonly observed on frosted window panes. Although condensation, if liquid, may enter an unpainted surface as fast as it forms and thus be up"***", any condensation on a visible surface will for convenience Moisture in Building Construction 133 Table 2.... Conversion Factors for Vapor Transfer Units \\ Muffin)y ffinntor fti ~\ to Obtain ) \ WV7 IMh gram* 124 hr*) (sq m) grata] IMtajft) (1/4 hr*) (aq m) by CUM method* erin* (hr) (*q ft) Pens* by Mae method* method* method A A B. 73.4 F method CAD, SO F method E 100 F 0.0597 0-144 ' 0.0540 0.0344 10.7 1 1.41 . 1-U 0.675 Nominal Tod Candrffefti % Xefafire Humidify on (he Two Side! of Specttsem - temperature from day to day while the weather dew-point temperature rises. When no water vapor is released in the space, the dew point tends to equal that of the outdoors (though it is likely to lag when there is slight ventilation). At times the dew-point temperature rises above the tempera . ture of waffs and floors with resulting condensation. If the basement is decorated the trouble may be serious. As an operating problem, the solution may be to reduce ventilation at times of high weather dew point, to warm the walls, or to dehumidify the space. Warming the walls, a slow process at best, is generally accomplished in favorable climates by excess ventilation. In a climate having low temperature at night, it may be feasible to ventilate only at night and thus reduce the moisture content of hygroscopic" materials which will then act as desiccants to retard the dew-point rise during the day. In'basement walls and floors insulation should be ap plied in the concrete or on its outside. Insulation placed on the inside of such walls eijminRtpH visible condensation but fos- Method Temper otare-f In cup Otrfdde cup A 7J.4 ' . 0 60 B 73.4 100 so C 00 0 50 D 90 100 50 E 100 .0 ; . . to ' * Date abuined by oat method cmnot be reliably ooaverted to another method. . ' To convert (24 hr) (aq m) (-m---m---H_g) to ptriau multiply by 1.52. here be called visible condensation to distinguish it from con cealed condensation. Within residences and public buildings, visible condensation in winter may damage decorative finishes and window 'sash. ' . Interior visible condensation occurs when any surface is colder than the dew point of the near-by air. The temperature of any such surface-wall, roof, or glass--is dependent upon the air temperature inside, and outside the building and the heat transfer coefficient U of the surface structure. Based on a value of 1.65 for the inside surface conductance, Fig. 4 shows the relative humidity in a room at 70 F at which visible con densation will appear at various U values. The curves for single and double glass at their usual V values are included. It should be noted that V values as commonly used are an average for a large area within which there may be spots, such as the studs in an insulated wall,-where the transmittance is higher. The inside surface temperature of a wall will, in gen eral, be lower at the bottom due to such things asstratifica tion of inside air and the effects of air leakage and of convec tion in walls with air spaces. Since condensation appears at any sufficiently cold spot, values from Fig. 4 can be applied - only with caution. As a result, the limit of relative humidity for a non-homogeneous wall is lower than might be inferred from its average U value. , Normally, glass is the most likely spot in a heated room for appearance of condensation, but an uninsulated wall surface shielded from radiation by furniture, may be equally cold. In some cases where condensation is barely avoided, the surface, being but little wanner than the dew-point tempera ture, is exposed to moisture damage--such as swelling, mold - or discoloration. ` - Visible condensation may occur also in summer. It'is often seen on basement concrete walls and floors that are cooled by the earth and which being massive, tend to bold a constant fig. 4 .... Relative Humidity at Which Visible . Condensation Will Appear on Inside Surface tore concealed condensation. The control of the latter will be discussed. A practical and fully effective technique for such control has, however, not been developed. Usually, sub-sur face dwellings designed for occupancy should be dehumidified. A similar situation is seen in dwellings with concrete floor slabs laid on the ground where such slabs are not a part . of the hpAting system. In a northern climate where high dew point temperatures occur in summer, condensation or very high relative humidity may damage rugs which are themselves contributors to the trouble since they reduce the floor slab temperature. Slab floors above grade are not so serious a problem as floor slabs on grade but. their response to air temperature change is slow. Faster warming is accomplished by tiie removal of 'rugs and abundant ventilation' at proper times. In their design, floot slabs should have as low specific heat and as high thermal resistance as is consistent with other requirements. Suitable insulation below the slab, especially well-drained gravel, will help somewhat. A top surface cover of value that is unaffected by water on its lower ride would be desirable in the less favorable northern cli mates. '. .. . The avoidance of interior visible condensation is partly a construction and partly an operating problem. It is accom plished by reducing the interior dew-point temperature or by raising the surface temperatures that are below the dew point, or both. The dew-point temperature may be lowered by giv- 134 CHAPTER 10 1959 Guide mg attention to the sources of the moisture, and in winter, may be controlled by ventilation, or possibly by some mois ture absorption process. The temperatures of the inside room surfaces in winter may be increased by adding insulation to outside walls, by double glazing of windows, by circulating warm air over the surface, or perhaps by direct heating of the surface. The most expedient method of overcoming a surface condensation difficulty will depend upon special conditions surrounding the problem. CONCEALED CONDENSATION IN HEATED BUILDINGS Water vapor produced in a building necessarily raises the vapor pressure above that outdoors thus providing the force that causes its diffusion into exterior walls. The amount of vapor-pressure rise in the building depends on the amount of vapor, produced and inversely on its .chance to escape. The resulting balance may be expressed in terms of relative humidity if the inside temperature is 70 F. The relative humidity in heated buildings covers nearly all of the possible range. In zero weather it may be only 10 percent in an 'office, and 85 percent in an industrial plant where humidification is required for a process, or where vapor release is incidental to a process. In residences the relative humidity in cold winter weather ranges from 10 percent to 60 percent, the latter fig ure applying to a very small, crowded and unventilated dwell ing. A 40 percent level is considered representative of a sub stantial number of modern tightly constructed gmall houses although the'average house relative hufiudity is. probably below 25 percent. Surveys in residences show that the rela tive humidity increases as would be expected in wanner weather, fig. 5 represents the results of one such survey.1 When water vapor is allowed tio enter a wall and condensa tion occurs on its outer cold' elements, it appears as frost or liquid. If the weather temperature rises frequently, frost melts and. becoming liquid, is likely to penetrate capillary materials like wood,' or run down when the surfaoe'is non absorbing or is already saturated with water. In weather the*. is continuously cold for a long period, the frost may build, back into a cavity or fibrous insulation and, when it reaches a wanner plane, will run to lower, cooler levels where it forms a mass of ice. Water seepage to the weather side may occur harmlessly in masonry walls when the weather is above freez ing but. water seepage into the building must obviously be avoided. In typical frame construction with wood fthe*i.hing which has large water absorbing capacity, seepage is rare occurs only after a long period of steady cold weather. More generally, moisture accumulates in wood sheathing and aiding through the colder months and reaches a peak in late winter, after which'the drying of spring and summer completes the annual cycle.1* The average winter temperature and its dura tion are factors in the condensation problem. In fig. 6 the map of tiie United States is divided into condensation zones based on winter, weather conditions. The solid linpw separating the zones follow state lin&s, and are those recommended by the Housing and Home Finance Agency for the guidance of own ers, builders, and architects.17 The dotted lines are the -- 20 F, 0 F, and +20 F isotherms of winter design temperature taken from Fig. 1, Chapter 12. It will be noted that there is reason ably good correlation between the zones determined by the two sets of lines. Zone I roughly includes those areas where the design temperature is --20 F or oolder; Zone II those for which the design temperature is zero to --20 F, aH zone III those at zero and warmer. Within each zone, de- grees of condensation trouble are to be expected, and similar corrective measures apply. - In roofs, the condensation problem is much the same as in walls. The roof covering may be even more resistant to the escape of vapor than wall coverings such as paint; and while paint is likely to be ruptured by excessive moisture, no such relief occurs in roofs. Thus roofs furnish conspicuous examples of rapid decay in lumber. - In crawl spaces over uncovered damp ground, a large water evaporation sometimes occurs and causes condensation on the . outer ends of floor joists and other members that are below the floor line and near the outdoors. Water vapor from the craw] space may also enter walls, be transported by rising air in a stack effect, and even reach the attic by this route when the wall structure permits. Ventilation, as discussed later in this chapter, is an important correction factor in these cases. ' Insulation in a wall or roof reduces heat loss and lowers the temperature of the outer elements of the structure, thus in- fig. 5____Relative Humidity in Dwellings . creasing the possibility of condensation if the vapor path to the cold surface is not blocked. Since low vapor resistance1 is a characteristic of fibrous insulation, the needed^ vapor resist ance must be provided by other means'. It is to be noted that, in typical residential conditions, condensation docs not occur in fibrous insulation itself, except, when frost has formed on sheathing and gradually built backward among the fibera. Wet insulation may result from this condition or from liquid condensation seeping down from a higher level. CONTROL OF CONCEALED CONDENSATION An excessive accumulation of moisture in walls (or roofs) . can be prevented by one or more of the following measures: (1) providing a vapor barrier to limit vapor entrance into the wall, (2) ventilating the building to reduce vapor pressure therein, or (3) ventilating the wall cavity to remove vapor that has entered. ` 1. Vapor Barrier. A vapor barrier is the principal and most obvious correction, but each measure is more effective if aided by the effect of another.- In habitations, some ventila tion of the living space, either incidental or planned, is neces sary. Also, a small amount of cavity ventilation is pgapntinl in cases where the vapor inflow, is not completely stopped and the moisture storing capacity of the outer wsill elements is slight. This applies to some prefabricated designs using metal siding. Vapor-barrier sheets are often built into the wall near the Moisture in Building Construction warm surface. In wood frame walls they may be applied to the inside surface of the studs. They are sometimes attached to the warm side of the insulating materials, or they may be applied on the cold ride of plaster base materials. Special designs may be attached like wall paper to the inride of the wall, when satisfactory from the decorative view point. Sheet barriers often contain asphalt as the vapor-resisting ingredi ent; metal foils, so placed that they are not too cold, may also be used. The interior wall board or finish material1 may itself be vapor resistant, or a barrier coating may be applied to its concealed side if that ride will not be too cold. The interior finished surface may be coated with a suitable paint having the required vapor resistance and also serving as the decorative finish, or it may be covered by another coat. , A paint coat on the interior finish, though of adequate re sistance, is not. likely to be as effective as a sheet barrier properly, applied during the wall construction. This applies especially to houses of more than one story having cavities in ceilings which open into the outside walls. Such cavities allow vapor entering the ceiling to diffuse or be transported to the cold areas. Stoppage of this path is difficult and re quires normally the painting of the ceiling as well as the walls. Similar treatment may be required on internal partitions, or at least the first stud space adjacent to a cold wall. The necessary barrier resistance depends on a number of factors. .When the vapor flow occurs in annual cycles as in heated buildings, the requirement is not as exacting as it is for a cold storage room where there is no chance for drying out an accumulation of moisture. In a heated structure covered on the outside with materials highly resistant to water vapor such as paint or roll roofing, the winter season is a 135 time of moisture accumulation in the cold outer elements and their safe moisture holding capacity is an important, factor in determining the barrier requirement.1* A house without sheathing requires a better barrier. A prefabricated design with only a sheet of metal outside of insulation requires very high barrier resistance. The interior vapor pressure and the length and severity of the winter are also important. . For typical frame dwellings with wood sheathing and siding in the northern United States, a barrier permeance of one perm or less has been found satisfactory. There are cases, however, in residential construction where a one perm bar rier would not.be adequate and there are also many industrial applications in which a very much higher vapor resistance is required. In any event, the choice of an adequate barrier im plies that its permeance be definitely established. The usually accepted test procedure for this purpose is a dry method at a temperature of 70 F to 80 F. If obtainable at reasonable cost (including good application), a barrier better than required should be chosen for any construction. Despite the theoretical possibility of safely discharging some vapor through a wall, a highw-thnn-mmimnm permeance is not preferred. An exact statement showing which buildings require a vapor barrier is not readily formulated. However, in view of the distressing results its omission may bring, it is tentatively recommended that the walls of every well constructed modem dwelling include a vapor barrier when the construction in cludes any material (hat would be damaged by moisture or its freezing. This applies to all condensation zones in Fig. 6 when toe U value for the wall is lower than 0.25 Btu per (sq ft) (hr) (F deg), and it applies in Zone I and Zone.II to walls of higher transmittance. In applying vapor resistance to a wall, there are certain Zone* Include Areal with Detrgn rofflperofvret about at follow*; Zone I, --20 F end lower; Zone II, 0 F to --20 F; end Zone III, above 0 F. Note that cross hatched areas ore ouldde of Zone* I end I/O Fig. 6 .... Condensation Zones in the United States 5^ 136 CHAPTER 10 1959 Guide fundamental principles that should be followed. First, ^the of the wall as practicable. Second, it should be continuous with no direct openings through the barrier: Good workman ship and application are very important. Workmanship that leaves two openings through the barrier, or around its margin, at different levels, connecting air spaces at only slightly dif ferent temperatures, leaves a path for thermosyphon air ro tation which will transport large amounts of water vapor from tiie warmer space to the colder. If a membrane barrier is used back of the plaster or interior finish, its joints should be made over some solid framing member, and not between the studs or in similar places. Usually a two-inch lap over a framing member will mulcg a sufficiently tight joint when the interior finish is applied. Such a lap, however, without back ing would not be adequate. Barriers attached to the warm side of insulation should form a continuous unbroken mem brane over the entire insulated area. Edges should be lapped over framing members; ends of strips should be fastened by lapping over plates or headers. AU openings for electrical fixtures and joints around window and door casings should be carefully sealed. Holes accidentally made in the barrier should be sealed. . ' 2. Ventilation of Luring Space. The second measure listed for the control of concealed condensation is ventilation of the house. This measure is obviously necessary as an accompani ment to a vapor barrier since, if the barrier blocks entrance into the walls, the water vapor must be removed by other means: No great volume of air change is necessary, however, and normal infiltration alone is frequently all that is required in winter weather. - The effectiveness of ventilation is shown in Fig. 7, which also shows the small amount of water vapor escaping into the barrier-equipped, well-insulated wails and ceilings (2000 sq ft) of a typical small dwelling, the floor being neglected. Evi dently, ventilation of 2000 cfh will remove 21 lb of vapor per day with the relative humidity at 40 percent, while at the same time 1.5 lb escapes into the structure. The total vapor production (22.5 lb) is a typical amount. Double glass will be barely safe from visible condensation as will be seen in Fig. 4. By reference to Chapter 6,2000 cfh appears to be near the minimum foe odor control, and ventilation would have to be higher when cooking is done. By reference to Chapter 11, it appears that usual infiltration will normally supply the necessary air change, but that supplementary ventilation may be necessary in kitchen and laundry for proper vapor control and for Hie reduction of peaks in relative humidity that would otherwise occur in those areas. * 3. Ventilation of Structure. The third measure listed for the control of concealed condensation is ventilation of the. struc ture itself. It is effective in certain cases especially as a supple ment to warm-side vapor resistance which is considerable but not of itself fully adequate. Air from outdoors is used. The vents must be shielded from the entrance of rain and insects. Attics and crawl spaces may be considered as parts of the structure, and for these portions ventilation is practically a necessity. Attic ventilation has long been an established prac tice but its effectiveness is likely to be ftinumahe-H by the newer practice of adding insulation to ceilings. Insulation re quires added ventilation which in turn necessitates adequate insulation. The recommended ventilation shown in Table 3 for dwellings17 is based on such insulation. The net area refers to the total of all openings free from obstructions. The use of louvers and 8-mesh screen (usually recommended) requires a gross area 2.25 times that listed. In Zone I of Fig. 6 a ceiling vapor barrier is recommended for all constructions. It is also necessary that stray openings from walls into the attic, or around a loose fitting attic door be avoided. The stack effect allows a large inflow of warm air from the dwelling, transport ing much vapor to a danger area. More desirable ventilation of the house can be arranged. Crawl spaces under dwellings where the earth is damp and uncovered require a high rate of ventilation. At least four Table 3.... Recommended Good Practice17 for Loftand Attic Ventilation* Hot Roof--Slop* Lass Mian 3 India* m 12 Inchat Condensation Zone I*: Total net area of ventilation should be ty>othb distributed uniformly at the eaves plus a vapor barrier in the top story ceiling. Free circulation must be provided through all spaces. Condensation Zone II and ill: Same as for Zone 1. ' Goble Roof--Slope over 3 India* ht 12 India* Condensation Zone I: Total net area of at least 2 louvers on opposite sides located near the ridge to be Hoothb plus a vapor barrier in the top story ceiling. Condensation Zone II: Same ventilation as for Zone I. A vapor barrier is not considered necessary. ' Condensation Zone HI: Same as for Zone II. Hip Roof Condensation Zone I: Total net area of ventilation should be Hooth* with Hoothb distributed uniformly at the eaves and )ioothb located at the ridge with all spaces interconnected. A vapor barrier should also be used in the top story ceiling. .Condensation Zone 11: Same ventilation as for Zone 1. A vapor barrier is not considered necessary. Condensation Zone III: Same as for Zone II. Gable or Hip Roof--Wrtfi Occupancy Coatomplatod Condensation Zone I: Total net area of ventilation should be Hoothb with Hoothb distributed uniformly at the eaves and %Qothb located at the ridge with all spaces interconnected. A vapor barrier nhould also be used on the warm side of the top full story ceiling, the dwarf walls, the sloping part of ' the roof, ana the attic story ceiling. Condensation Zone II: Same as for Zone I. Condensation Zone III: Same as for Zone I except that a vapor barrier is not considered necessary if insulation is omitted. (Vapor Bcrrmr, I pans; WaO ond Coiling Aim 2000 tq ft liudoM] Rg. 7.... Water Vapor Balance in a Dwelling - It b recognized that in many areas inenoaed ventilation may be desuobd tor cummer comtort. For winter comfort, initiation ic recommended between a ' tiring apace and a loft or attic ventilated at theae rates- b Refers to area eadoaed within boildio* lines at cave bveL * The tone number* refer to Fig. 4- Moisture in Building Construction 137 openings, one at each corner, as high as possible, should be provided.17 Their total net area may be calculated by the formula: Similar considerations apply in tire'case of cold rooms whether constructed inside a heated building or as a separate building. In the latter case, cold rooms operating above' 2L A ` 100 + 300 freezing provide some periods of vapor reversal in winter GO) but such drying can be of little help. Refrigerators, however, where: if lined with cement or other vapor permeant material, will allow slight amounts of vapor to pass and to that extent L -- the perimeter of the crawl space, linear feet. reduce the accumulation of moisture that may have pene A " the area of the crawl space, square feet, trated the barrier. While this is helpful, emphasis must be a " the total net area of all vents, (or the gross area if a 4-mesh screen is used) square feet. placed on an adequate warm-side barrier not greater than 0.1 perm. , Summer air cooling for comfort does not normally create This ventilation is usually sufficient but cools the first serious vapor problems in exterior walls and ceilings. Normally floor so much that insulation is needed. A better treatment the cooled air is little, if any, colder than the dew point of is a cover on the damp ground. This cover may be a concrete the outdoor atmosphere and there are no areas of condensa slab, or merely heavy roll roofing laid on a graded surface tion. The design dry-bulb and design wet-bulb temperatures with its edges lapped 2 in. (but not necessarily cemented). in common use oa given in Table 2, Chapter 13, tend to bear With this barrier, the vent area may be reduced to 10 per this out. For the 315 cities in the United States, for which cent of that calculated by Equation 10. design values are given, only 78 have design wet-bulb tempera In building walls, cavity ventilation can be applied in a tures in common use over 75 F. Outdoor dew-point tempera moderate climate as the sole vapor control system. In general, tures, especially peak values, may exceed the design wet- however, air passages in walls designed to remove an unre bulb temperatures in common use, but these will seldom be stricted vapor supply are unduly large and may waste con greatly in excess of 75 F for any prolonged period of time. siderable heat. On the other hand, a barrier as the only con Condensation within exterior walls which are exposed' to trol measure would, in some cascs. require so high a resistance indoor air at 75 F will seldom be as serious as for the winter as to be impractical. Ventilation of the structure in conjunc condition. tion with a vapor barrier, is a procedure with important ap A vapor barrier to prevent condensation within exterior plications, but its general utility has not been fully investi walls under summer cooling conditions would normally be gated. Ventilation is most effective when each structural located on the outside of the insulation, whereas the location space has a clearly defined air passage with an inlet and outlet. . for the winter condition is on the inner side. The use of vapor In walls a small thermosyphon effect may be utilised by locat barriers at both locations is not without difficulty because ing one vent at the bottom and one at the top of-each space. they not only restrict the entry of moisture into the insula The best time to vapor-proof a building is during its con tion but also restrict the escape of any moisture. It is generally struction. After a building is completed, ventilation of the considered best in dwelling construction to locate the vapor occupied space is the most easily applied of the three basic barrier for the more serious case of condensation in winter, control measures. Paint that is chosen for its low vapor per - and to disregard the summer case even when some condensa meance can be applied as a barrier on the interior with good' tion may be expected. The corresponding situation in cold- results, care being taken that all areas, including parts of storage buildings in which there may be a much more serious partitions and ceilings which offer an indirect vapor path to reversal of vapor flow conditions from winter to summer ' the cold wall, are covered. Ventilation of the wall cavity is poses a wall design problem that has not yet been fully, effective in certain cases especially to supplement the fore resolved. going measures. When such venting is required, each cavity Some observations made by the National Research Council space isolated by framing should be separately vented with of Canada, but not yet publicly reported, would indicate on inlet and outlet judiciously placed, to accomplish proper that serious wetting within walls can occur in summer under air change. .. special conditions. The walls of test huts of brick masonry, CONDENSATION IN COOLED STRUCTURES Water vapor is sometimes an even greater problem in cooled than in heated structures, but the basic facts of its but finished inside with strapping, insulation, vapor barrier, and plasterboard interior finish, were opened during a sunny period that followed a rain. Extensive wetting was observed in the insulation, and particularly on the back of the vapor migration and condensation on cold surfaces are the same. Refrigerators, cold pipes, and cold vessels all require insula- tion and should be provided with a vapor barrier. The barrier,as always, should be placed on the warm side of the insulation and as close as possible to the warm surface of any enclosure. It resists the movement of water vapor toward the colder parts of the structure, and its job is even more exacting tkn that required in residential construction. In the case of on insulated cold pipe line, the process is likely to be uninter rupted for years and there is no chance for vapor that enters the insulation to dry out periodically. Also, no vapor can escape from the-cold side, if this is a metal (vapor tight) pipe. For such an application vapor control requires insulatr ing material that is itself very highly resistant to water vapor or a coating whose permeance is tire minimum ob barrier. The brick wall which was unusually absorptive had taken on substantial quantities of water during the period of. rainfall. Subsequent heating by the sun had driven the moisture as vapor into the wall where it condensed and caused serious wetting. The construction in question did not have protection for the strapping and insulation in the form of parging or paper on the inside of the brick. Walls having absorptive exterior coverings capable of absorbing and storing considerable quantities of water during a rain and providing little resistance to vapor flow into the insulation from the outdoors, may experience serious interior wetting by condensation under such-unusual conditions. No wetting occurred in a construction similar to that described above when a saturated whgathing paper was used between the tainable, not over 0.1 perm. Metal coverings are desirable but insulation and the brick. It would appear that the provision difficult to apply. ' ' of moderate resistance to vapor flow such as that provided 138 CHAPTER 10 1959 Guide by parging or a good exterior grade sheatiling paper on the outside of the insulation can be effective in such cases. Vapor which diffuses inwards under cooling conditions adds to the cooling load. Vapor barriers in walls installed for winter conditions are a help in reducing this. However, if condensation does occur on the back of a vapor barrier installed on the inside of the insulation, the latent heat which is then released on the inside of the insulation may add to tire heat gain through the wall. REFERBsICES 1 S. C. Hite and J. L. Dray: Restarch in Home Humidity Control (Purdue University, Engineering Experiment Station Research Seriet No. 106. November 1948). . * . * S. C. Chang and N. B. Hutcheon: Dependence of water vapor permeability on temperature and humidity (ASHAE Transactions, Vol. 62, 1956, p. 437). * F. A. Joy and E. R. Queer: Permeance measurement im proved by special cell (ASHVE Transactions, Vo). 55, 1949, p. 377). .. 4 F. A. Joy, E. R. Queer, and R. E. Schreiner: Water Vapor Transfer Through Building Materials (Pennsylvania State College, Engineering Experiment Station Bulletin No. 61, December 1948). * J. D. Babbitt: The diffusion of water vapor through vari ous-building materials (Canadian Journal of Research, Feb ruary 1939, p. 15). . * F. A. Joy and D. R. Fairbanks: Effect of unbalanced air. ressure on permeance (ASHAE Transactions, Vol. 62, f956, p. 451). 1 R. M. Barren Diffusion In and Through Solids (Cambridge ' Press, London, 1951). 1 L. V. Teesdale: Remedial Measures for Building Construc tion (U. S. Forest Products Laboratory Report R1710, 1947). *F. B. Rowley, A. B. Algren, and C. E. Lund: Methods of Moisture Control and Their Application to Building Construc tion (University of Minnesota, Engineering Experiment Station Bulletin No. 17). s* H. J. Barre: The Relation of Wall Construction to Moisture. Accumulation in Fill-Type Insulation (Iowa State College of Agriculture and Mechanic Arts, Agricultural Experiment Station Bulletin No. 271, 1940). 11 P. F. McDermott: Moisture migration: a survey of theory and existing knowledge (Refrigerating Engineering, August 1941, p. 103). " R. I. Wray and A. R. Van Vorst: Permeability of paint films to moisture (Industrial and Engineering Chemistry, Vol. 25, 1933, p. 842). 14 R. R. Britton and R. C. Reichel: Water Vapor Trans mission of Building Materials Using Four Different Testing Methods (U. S. Housing and Home Finance Agency Technical Bulletin No. 12, January 1950). 14 E. R. Bell, M. G. Seidl, and N. T. Krueger: Water-vapor permeability of building papers and other sheet materials (ASHVE Transactions/Vol. 57,1951, p. 287). 11 Value from unpublished texts of Pennsylvania State Col lege Experiment Station. . 14 F. A. Joy: Basic concepts of water vapor migration and their application to frame walls (ASTM Special Technical Pub lication No. 119, 1951, p. 2). n Condensation Control in Dwelling Constructions (U. S. Housing and Home Finanoe Agency; 1949). BIBLIOGRAPHY H. W. Wooley: Moisture Condensation in Building Walls (National Bureau of Standards Report BMS 63, December 14, 1940). F. B. Rowley, A. B. Algren. and C. E. Lund: Condensation of moisture and its relation to building construction and opera tion (ASHVE Transactions, Vol. 45,1939, p. 231). P. D. Close: Permissible relative humidities in humidified buildings (ASHVE Journal Section, Heating, Piping and Air Conditioning, December 1939, p. 766). F. B. Rowley, A. B. Algren, and C. E. Lund: Condensation within walls (ASHVE Transactions, Vol. 44, 1938, p. 95). H. Edenbolm: Moisture movement and moisture distribution in the walls of buildings (Meddelanden Fran (aten Forskningskommitte for Lantmannabyggnader No. 5, 1945, p. 53, available as Technical Translation TT-361 from the National ResearchCouncil of Canada, 1952). J. D. Babbitt: Physics of Condensation in Buildings (Na tional Research Council of Canada Bulletin No. 2). L V. Teesdale: Comparative resistance to vapor transmission of various building materials (ASHVE Transactions, Vol. 49, 1943, p. 124). Durability of moisture-resistant membrane materials in con tact with the ground (Housing and Home Finance Agency, Housing Research No. 4, October 1952, p. 23). Proposed method of test for water vapor transmission of building materials utiliting the Penn State-Armstrong cell (ASTM Bulletin No. 215, July 1956, p. 63). Heat and water vapor transmission apparatus for insulated panels (National Bureau of Standards, Technical News Bulle tin, November 1954, p. 157). F. A. Joy and A. W. Sherdon: Automatic permeance measure ment by the permeometer (ASHAE Transactions, Vol. 59, 1953, p. 435). F. B. Rowley: A theory covering the transfer of vapor through materials (ASHVE Transactions, Vol. 45, 1939, p. 545). F. G. Hechler, E. R. McLaughlin, and E. R. Queer: Simul taneous heat and vapor transfer characteristics of an insulat ing material (ASHVE Transactions, Vol. 48, 1942, p. 505). J. A. Paxton and N. B. Hutcheon: Moisture migration in a closed, guarded hot plate (ASHVE Transactions, Vol. 58, 1952, p. 301). C. G. Gurr, T. J. Marshall, and J. T. Hutton: Movement of water in soil due to a temperature gradient (Soil Science, November 1952, p. 335). W. A. Hadley and Ray Eisenstadt: Moisture movement in soils due to temperature difference (ASHAE Transactions, Vol. 59, 1953, p. 395). K. R. Solvason: Moisture in transient heat flow (ASHAE Transactions, Vol. 62, 1956, p. 111). H. F. Winterkorn: Fundamental similarities between electroosmotic and thermo-osmotic phenomena (Proceedings 17th Annual Meeting, Vol. 27, Highway Research Board, 1947, p. 443). S. C. Chang and N. B. Hutcheon: Performance of desiccants in the dry pan test for water vapor permeance of membranes (Canadian Journal of Technology, September 1953, p. 175). F. A. Joy: Thermal conductivity of insulation containing moisture (ASTM Special Technical Publication No. 217, Febru ary 1957, p. 65). J. S. Cammerer: The effect of moisture on heat transmission through building and insulating materials (Wdrme und K&ltetechnik, September 1939, p. 126, available as Technical Trans lation TT-317 of the National Research Council of Canada, 1952). H. B. Jesperson: Thermal conductivity of moist materials and its measurement (Journal of IHVE, August 1953, p. 157). D. Krischer: Heat conductivity and water vapor diffusion in materials for insulation against cold (Wdrme und KdltetechniJfc, 1941, 43(0), p. 2, translation available from British Build ing Research Station as Library Communication No. 492). D. A. De Vries: The thermal conductivity of soil (Mededelingen van de Landbouwhogeschool te wageningen, 1952, 52(1). p. 1, translation available from British Building Re search Station as Library Communication No. 759). C. H. Johansson: Moisture transmission and moisture dis tribution in building materials (Wdrme-Ventilations-Sanitetstek, 19 : 67, 1948, available as Technical Translation TT-189 from the National Research Council of Canada). J. D. Babbitt: The movement of moisture through solids (ASTM Bulletin No. 212;February 1956, p. 58). J. R. Philip and D. A. De Vries: Moisture movement in porous materials under temperature gradients (American Geo physical Union Transactions, April 1957, p. 222). CHAPTER 11 INFILTRATION AND VENTILATION Causes of Infiltration, Infiltration Due to Wind Pressure, Infiltration Due to Temperature Difference, Sealing of Vertical Openings, Infiltration Measurement, Natural Ventilation, Wind Forces, Temperature Difference Forces, Heat Removal, Effect of Unequal Openings, Combined Wind and Temperature Forces, Types of Openings,. General Ventilation Rules, Ventilation of Animal Shelters, Garage Ventilation INFILTRATION is the air leakage through cracks and of openings on the windward and leeward sides, and on the interstices, around windows and doors, and through lower floors and on the upper floors; and (6) influence of floors and walls. Its magnitude depends on the structural a planned air supply and the related outlet vents. Tight design, workmanship, and condition of the building. The rate of infiltration cannot be controlled by the inhabitants construction is essential for preventing large heat loss due to infiltration. of the building to any. considerable extent. Natural ventila tion is the controlled displacement of air through openings, In view of the meager information available on infiltra tion, a cooperative investigation was undertaken in 1954 in such as windows, doors, and ventilators as well as through combustion heating devices. which the infiltration rates of residences were obtained by actual measurement.1' * In 1956 a study was started at the CAUSES OF INFILTRATION ASHAE Research Laboratory to obtain additional infor mation on infiltration through building entrances.* These .The air leakage which takes place through various aper tures in buildings must be estimated in heating and cooling studies are yielding quantitative information on factois af fecting infiltration rates, but more data are still needed. calculations and enough heating or cooling capacity provided to offset the heat lost or gained by the air leakage. The INFILTRATION DUE TO WIND PRESSURE rate of air flow into and out of a building depends on the The wind causes a pressure to be exerted on one or two magnitude of the pressure difference . between the inside sides of a building. As a result, air comes into the building and outside of the structure and on- the resistances presented on the windward side through cracks or porous construction, to this pressure difference. The pressure difference exerted _ and a similar quantity of air leaves on the leeward side on the building walls by the air may be caused either by through like openings. In general, the resistance to air wind or by a difference in density of the air inside and out movement is similar on the windward to that on the leeward side the building. The effect of the wind depends on the side. This causes a building up of pressure within the building, interrelation of the speed and direction of the wind and the and a lesser air leakage than that experienced in single wall exposure of the building. The effect of the difference in the tests as determined in the laboratory. It is assumed that density of the air depends on the magnitude of the indoor- actual building leakages, owing to this building up of pres outdoor temperature difference, the height of the rooms, the sure, will be 80 percent of laboratory test values. While shape of the openings, and their elevation in the room or there are cases where this is not true, tests in actual buildings building. The effect of the difference in density is often re substantiate the factor for the general case. Mechanical ferred to as the chimney or stack effect. The pattern of air ventilating systems are frequently designed to produce flow through any part of the structure depends on both the positive or negative pressures in an enclosure, which are pressure difference and the openings. In general, when the greater or lower than prevalent wind pressures. In such pressure difference is the result of wind pressure, air will designs, if the specified rate at which air is to be supplied enter the building through openings in the windward walls to, or removed from, the enclosure by positive means, ex and leave through openings in the leeward walls or through ceeds the infiltration rate, it is common practice to use the ventilating ducts in the roof. When the pressure difference greater value in determining the heating capacity to warm is caused by the indoor-outdoor temperature difference the the outdoor air. flow will be along the path of least resistance from inlets at lower levels to outlets at higher levels in a heated build Infiltration Through Walls ing or in the opposite direction for an air-conditioned build ing. An exact estimate of the amount of infiltration under design conditions is difficult to make. The complicating factors include (1) variations in building construction, par ticularly as to width of crack or size of openings through which air leakage takes place; (2) variations in wind ve locity and direction; (3) exposure of the building with re Data on infiltration/ through brick and frame walls are given in Table l.4 The brick walls listed in this table are walls that show poor workmanship, and which are con structed of porous brick and lime mortar. For good work manship, the leakage through hard brick walls with cementlime mortar does not exceed one-third the values given. These tests indicate that plastering reduces the leakage by about 96 percent; a heavy coat of cold water paint, 50 per-' spect to air leakage openings, and with respect to adjoining buildings; (4) variations in outdoor temperatures which in fluence the chimney effect; (5) relative area and resistance cent; and three coats of oil paint carefully applied, 28 per cent. The infiltration through walls ranges from 6 to 25 percent of that through windows and doors in a 10-story 140 CHAPTER 11 1959 Guide Table 1 .... Infiltration Through Walls* tipnmt in cubic feat per laprare tool) (boor) Typo of Woff Wind Vofodfyi Mifei per Hour 5 10 15 20 .25 30 Brick WaUb 8H in. Plain Plastered* 2 4 s 12 19 23 0.02 0.04 0.07 0.11 0.16 0.24 Plain 13 in. Plastered* Plastered11 1 4 7 12 16 21 tO.Ol 0.01 0.03 0.04 0.07 0.10 0.03 0.10 0.21 0.36 0.53 0.72 Frame Wall, lath and plas- 0.030.07 0.13 0.18 0.23 0.26 .ter* * The value* tiwa in (his table are SO percent las than text values to allow (or building up of pressure in rooms, and are baaed on test data reported in the paper* listed in chapter footnotes. b Constructed of porous brick and lime mortar--workmanship poor. * Two coats prepared CTpeom plaster on brick. * Furring, lath, and two coats prepared gypsum plaster on brick. * Wall construction: bevel aiding painted or cedar ahingla, eheatbing. build ing paper, wood lath, and three coata gypsum plaster. office building, with imperfect sealing of plaster at the base boards of the rooms. With perfect sealing the range is from 0.5 to 2.7 percent; or a practically negligible quantity, which indicates the importance of good workmanship for proper sealing at the baseboard. It will be noted from Table I that the infiltration through properly plastered walls can be neglected. ' : The value of building paper, when applied between sheathing and shingles, is indicated by curve 3D-7D, Fig. 1, which represents the effect on outside construction only, without lath and plaster. The effectiveness of plaster prop erly applied is no justification for the use of low grade building paper, or of the poor construction of the wall con taining it. Not only is it difficult to secure and maintain the full effectiveness of the plaster, but also it is highly de sirable to have two points of high resistance to air flow with an air space between them. The infiltration indicated in fig. 1 is that determined in the laboratory, and should be multiplied by the factor 0.80 to give proper working values. Window and Door Leakage considered as the clearance. The length of the perimeter opening or crack for a double-hung window is equal to three Uliues the width, plus two limes the height, or iu other words, it is the outer sash perimeter length, plus the meeting rail length. All of the window crack in any given room is not necessarily used in estimating the infiltration heat loss by the crack method. The length of crack to be selected in any given case depends on the number of exposed sides, as explained in Chapter 12. - Values of leakage shown in Table 2 for the average double-hung wood window were determined by using, on ' nine windows tested in the laboratory, the average measured crack and clearance of a large number of windows found in a field survey. In addition, the table gives figures for a poorly fitted window. All of the figures for double-hung wood windows are for the unlocked condition. Just how a window is closed, or fits when it is closed, has considerable influence on the leakage. The leakage will be high if the sash are short, if the meeting rail members are warped, or ' if the frame and sash are not fitted squarely to each other. It is possible to have a window with approximately, the average crack and clearance that will have a leakage at least double that of the figures shown. Values for the aver age double-hung wood window in Table 2 are considered to be easily obtainable figures, provided the workmanship on the window is good. Should it be known that the windows under consideration are poorly fitted, the larger leakage values should be used. Locking a window generally decreases its leakage, but in some cases may push the meeting rail members apart and increase the leakage. On windows with large clearances, locking will usually reduce the leakage. Wood casement windows may be assumed to have the same unit leakage as for the average double-hung wood window when property fitted. Locking, a normal operation in the closing of this type of window, maintains the crack at a low- value. For a metal pivoted sash,, the length of crack is the total perimeter of the movable or ventilating sections. Frame leakage on steel windows may be neglected when they are property grouted with cement mortar into brick work or concrete. When they are not properly sealed, the linear feet of sash section in contact with steel work at mullions should be figured at 25 percent of the values given in Table 2 for industrial pivoted windows. When storm sash are applied to well fitted windows, some There are two methods of estimating air leakage through window and door cracks, nameiy, (1) the crack method, and (2) the air change method. The crack method is generally regarded as being more accurate than the air change method, provided the variables, such as crack width and clearance, can be properly evaluated. ' Crack Method The crack method is based on known air leakage factors for various types of windows, and widths of crack and clearance. The wind velocity and length of crack are also considered when the crack method is employed. The amount of infiltration for various types of windows is given in Table 2.* The fit of double-hung wood windows is determined by crack and clearance. Crack thickness is equivalent to onehalf the difference between the inside window frame dimen sion and the outside sash width. The difference between the. width of the window frame guide and the sash thickness is Fig. 1 .... Infiltration Through Various Types of Shingle Construction Infiltration and Ventilation 141 Table 2 .... Infiltration Through Windows Expreaed in cubic feel par foot of crock per hour* Double-Hung Wood Sash Windows (Unlocked) Around frame in masonry wall--not calkedb...................... :. Around frame in masonry wall--calkedb.................................. Around frame in wood frame construction6.................... Total for average window, non-weatherstripped, H6-in- crack and %-in. clearance.* Includes wood frame leakage*...................................................................... .............................. Ditto, weatherstrippedd.................................................................. Total for poorly fitted window, noo-weatherstripped, in. crack and clearance.* Includes wood frame leakage4.................................................. \.................................. Ditto, weatherstripped*........................................................ 3 1 2 7 4 27 6 Wind Velocity, Ada* per Hour 10 15 20 25 30 8 14 20 27 '35 2 3 4 56 6 11 17 23 30 21 39 59 80 104 13 24 36 49 63 69 111 154 199 249 19 34 51 71 92 Double-Hung Metal Windows( Non-weatherstripped, locked.............................................. Non-weatheretripped, unlocked................................................... Weatherstripped, unlocked.................................................. 20 20 6 45 47 19 70 96 125 154 74 104 137 170 32 46 60 76 Rolled Section Steel Sash Windows1 Industrial pivoted, Ke-in* crack*.............................................. Architectural projected, }a-io- craekb................................ Architectural projected, %-in. crackh.................................. Residential casement, H-m* crack4........................................... Heavy casement section, projected, H*-in- crack'............... Heavy casement section, projected, Ms-in* crack'............... 52 15 20 6 14 3 8 108 36 52 18 32 10 24 176 244 304 372 62 86 112 139 88 116 152 182 33 47 60 74 52 76 100 12S 18 26 36 48 38 54 72 92 Hollow Metal. Vertically Pivoted Window' .... 30 88 145 186 221 242 of pressure in rooms, _ *! vjlueaciven for trim leakage ai* per foot of sash psimeter, as determined far doable-bung wood windows. Some of the frame leakage in masonry wall* orig lutes m the brick wall itself, and cannot be prevented by calking. For the additional reason that calking la not dona perfectly and efeterimatea with it is con sidered advisable to choree the masonry frame leakage value* far calked frame* a* the average determiua by the calked and oon-ralked teats. . sefiatsoonf tchoendaviteiorangse. doable-hang wood window waa determined a* He-in..e--r-ack and Ha-in. clearance by measurements on approximately (00 windows *-- * The value* given are ^e totals for the window opening per foot of aax5' perimeter, and include frame Irokage and so-called etsrwtere Uakaft. The frame tcakaga values included are tor wood frame construction, but apply as well to masonry construction assuming a SO percent efficiency cf frame <*rv*g * A Hs-in. erack and rirarancs represent a poorly fitted window, much poorer than average. Window* tested in place in building, ao that no reduction from tat values is necessary, aa mentioned in footnote a. . * Industrial pivoted window generally used in industrial buildings. Ventilator* horisontaily pivoted at >--or slightly above, lower part swinging mi 'Awhiteetiadly protected made d earns sections as industrial pivoted, except that outside framing member a heavier, and it ^ refinements in weathering and hardware. Used in acroi-monumental building* such as schools. Ventilators awing in or out and are balanced on ride arms. Jkx-in. mack is obtainable in *1-- beat prac tice cs manufacture and installation, H-in. crack ooasideed to represent average practice. 'Of same design and section shapes as eo-callcd ksasy action eojrawnt, but of lighter weight. Ht-in. crack is obtainable in the bat practice of manufacture and in stallation, Ha-in. creek considered to represent average practice- . klade of heavy sections. Ventilators swing in or out and stay set at any degree of opening. W-in. creek is obtainable in the beat practice of manufacture and in stallation, m-in- oack considered to represent average practice. Known at Interamdiate Window* by steel window manufacturers. * With uisaunaUe rare in installation, leakage at contacts where windows are attached to steel framework and at mulliona, is negligible- With H<-in. oack, repteinstallation, leakage at Contact with steel framework is about one third, and at mullions, about one-sixth of that given for industrial pivoted windows in reduction in infiltration is secured; the application of the sash provides an air space which reduces the heat trans mission and helps prevent the frosting of the windows* By applying storm sash to poorly fitted windows, a reduction in leakage of 50 percent may be obtained, the effect, so far as air leakage is concerned, being roughly equivalent to that obtained by the installation of weatherstrips. Door Leakage Doors vary greatly in fit because of their large sue and tendency to warp. For a well fitted door, the leakage values for a poorly fitted double-hung wood window may be used. If poorly fitted, twice this figure should be used. If weatherstripped, the values may be reduced one-half. A single door that is frequently opened, as might be the case in a store, should have a value applied three times that for a well fitted door. This extra allowance is for opening and closing losses, and is kept from being greater by the fact that doors are not used as much in the coldest and windiest weather. The infiltration rate through swinging and revolving doors is generally a matter of judgment by the engineer making cooling load determinations. In the absence of adequate re search data, the values given in Table 3 may be used to represent current engineering practice. Some tests of infiltra tion through swinging and revolving doors have been re ported.1 The data in Table 3 are indicative of what might be expected in this connection, but it should be noted that Table 3 is based on a no-wind condition, and therefore is not directly applicable to heating design. A wide range of infiltration rates would be expected for swinging doors because of variations in the indoor-outdoor pressure difference caused by wind, temperature differences, and the degree to which a heating or an air-conditioning 142 CHAPTER 11 1959 Guide Table 3 .... Infiltration Through 72-lndi Revolving Door end 36-lndt Swinging Door'- b (Cubic fsel per person per poaspt) Utago Frooty-Re rolrtag Door Door tqoippod with *"* Infrequent........................ Average............................ Heavy............................... 75 60 40 60 50 40 36-Inch Swinging Door...............................20 to 100 * These figure* sre based on the sssumptioo that tbere b po wind pressure tad UM swinging doore in in use in one will only. Any swinging doors in other wells should be kept elceed to insure sir conditioning in accordance with these leenmmywlel etenrlerrk b From AfpUeatioa Angincrrtnf Standard* Jar Air Canditianinf Jar Cemfor* 1941, Air Conditioning A Refrigeration Institute Inc.. Washington, D. C. and ino experimental data of National Bureau of Standards. Used by permission. system tended to raise or lower the inside pressure by blower action. The frequency of door usage would also affect the amount of leakage per passage. Air Change Method The amount of air leakage may be estimated by assuming a certain number of air changes per hour for each room, the number of changes assumed being dependent upon the type, use, and location of the room, as indicated in Table 4. Where it is not possible to determine or predetermine with ac curacy the width of crack or clearance of windows, or when other sources of air leakage cannot readily be evaluated, as is often the case, the use of the air change method may be justified* - The values in Table 4 may be used with reasonable accuracy for residences, and are the requirements for each room. The total infiltration allowance for the entire build ing should be one-half the sum of the infiltration allowances of the individual rooms, since whatever air enters on the windward side, generally leaves the building on the leeward side, and the infiltration requirements therefore do not exist simultaneously on all sides or in all rooms. An allowance of one air change per hour for all sources of air leakage for the entire volume may be considered average for a well con structed residence. _ The air leakage, due to opening and closing of doors in vestibules, is sometimes based on the air change, method, even though the air leakage estimates for other rooms are based on the crack method. Except for vestibules and re ception halls, it is not advisable to attempt to apply the air change method to factories and industrial and commercial buildings, because of the wide variations in the type and percentage of fenestration which is the principal source of air leakage in such buildings. INFILTRATION DUE TO TEMPERATURE DIFFERENCE The air exchange due to temperature difference, indoor to outdoor, is a chimney effect, causing air to enter through openings at lower levels,' and to leave at higher levels when the building is heated or causing flow in the reverse direction when the building is cooled. This air exchange is usually of considerable importance in tall, single-story buildings with openings near the ground level and near the ceiling; it should also be considered in tall, multi-story buildiDgs unless the sealing between various floors is nearly perfect; and may be appreciable in one-story buildings with base ments and attics. The flow of air through a building under the influence of indoor-outdoor temperature difference is quite complex except for single-story structures without a basement or attie. It can best be understood by visualizing the build ing as a complex chimney with a number of passages and a number of restrictions. The basement represents the lower section of this imaginary chimney with air moving inward through cracks in the walls and around windows and doors. The air then moves upward through cracks and openings in the floor which acts like a damper in the chimney. Above the floor the chimney has many parallel passages consisting of the several rooms and the hollow wall spaces in certain types of construction. These separate passages are all interconnected by cracks and also com municate with the outdoors through cracks and fissures. The ceiling acts as another damper with air flowing up ward through various cracks and openings. This condition is repeated in every story of a multi-story building and can be further complicated by open stairways, elevator shafts, and utility ducts. The attic finally represents the union of all the parallel passages in the chimney with the outward flow of air being again restricted by the roof con struction. Since the chimney effect in a building produces a neg ative pressure and an inward flow of air at the lower levels and positive pressure and outward flow at the higher levels, a neutral zone* exists near midheight where there is no pressure difference between indoors and outdoors, if the openings are about uniformly distributed in a vertical direction. At the neutral zone there would be no air flow througb openings in the outride walls as a result of temperature differences. The infiltration caused by the indoor-outdoor temperature differences can be calculated by means of. the crack method described earlier in this chapter for determining the in filtration caused by wind pressure. This is done by deter- milting the equivalent wind velocity that would produce the same.rate of infiltration as was caused by the prevailing temperature difference. It is recommended that one-half the total crack length of the building be used for this computa tion. To determine the infiltration caused by the temper ature difference, one-half the crack length of the'building is multiplied by the infiltration coefficient from Table 2 Table 4 .... Air Changes Taking Place under Average Conditions in Residences, Exclusive of Air Provided for Ventilation* ' Kind of Room or BtriWmg Number of Air Change* Taking Pfoce per Hovr Rooms, 1 side exposed......................... Rooms, 2 sides exposed....................... Rooms, 3 sides exposed........................ Rooms, 4 sides exposed........................ 1 IK 2 2. Rooms with no windows or outside doors.................................... .................. Entrance Halls....................... ................ Reception Halls...................................... Bath Rooms............................................ M to H 2 to 3 2 2 * For rooms with wcatherstripped windows or storm sssh, use yi these vsluce, where applicable. but never las then H eir change. Infiltration and Ventilation 143 corresponding to the equivalent wind velocity computed from the following equation developed from baric relation ships between velocity, pressure, density, and temperature. where V. = BVh(u ~ u) a) ' that an air inlet area not less than the area of the smoke pipe connection be provided if adequate air supply at all times is not assured. Similarly, the code for multiple dwellings requires a permanent opening to the outdoor air for rooms containing fuel-burning appliances having a gross capacity in excess of 250,000 Btuh. V, -- equivalent wind velocity corresponding to the tem perature difference (I< -- <), miles per hour. h -- height of rooms, feet. U =* indoor temperature, Fahrenheit. t, " outdoor temperature, Fahrenheit. B = a constant to account for leakage through floor and ceiling and for the number of stories in the building. The constant B would be 0.12 for a single-story building or for any story of a multi-story building whose floor and ceiling were impervious to air, whereas the value of B has been found to be approximately unity for a single-story frame building with basement and attic having double wood flooring, plastered ceiling, and the walls finished with plasterboard on the inside. The value of this constant would increase as the number of stories increases and for stories farther removed from the neutral zone in either direction in buildings that lack perfect sealing between stories. Sealing of Vertical Openings In tall, multi-story buildings, every effort should be made to seal off vertical openings, such as stair-wells and elevator > shafts, from the remainder of the building. Stair-wells should be equipped with self-closing doors, and, in ex ceptionally high buildings, should be closed off into sections of not over 10 floors each. Plaster cracks should be filled. Elevator enclosures should be tight, and solid doors should be used. If the sealing of the vertical openings is made effective, no allowance need be made for the chimney effect. Instead, the greater wind movement at the greater heights makes it advisable to install additional heating surface on the upper floors above the level of neighboring buildings, this additional surface being increased as the height is increased. One arbitrary ride is to increase the heating, surface on floors above neighboring buildings by an amount ranging from 5 percent to 20 percent. This extra heating surface is required only on the windward ride and on windy days, and hence, automatic temperature' control is especially de sirable with such installations. - In rtair-wells that are open through many floor levels, although closed off from the remainder of'each floor by doors and partitions, the stratification of air makes it advisable to increase the amount of heating surface at the - lower levels, and to decrease the amount at higher levels. One rule is to calculate the heating surface of the entire stair-well in the usual way, and to place 50 percent of this in the bottom third, the normal amount in the middle third, and the balance in the top third. NATURAL VENTILATION Ventilation by natural forces finds application in indus trial plants, public buildings, schools, dwellings, garages, and in farm buildings. The natural forces available for moving air into, through, and out of buildings are: (a) wind forces, and (5) the difference in temperature between the air inride and out ride a building. The air movement may be caused by either of these forces acting alone, or by a combination of the two, depending upon atmospheric conditions, building de sign, and location. The ventilating results obtained will vary, from time to time, due to variation in the velocity and direction of the wind, and the temperature difference. The arrangement, location, and control of the ventilating open ings should be such that the two forces act cooperatively rather than in opposition. WIND FORCES In considering the use of natural wind forces for pro ducing ventilation, account must be taken of: (1) average wind velocity; (2) prevailing wind direction; (3) seasonal and daily variations in velocity and direction; and (4) local wind interference by nearby buildings, hills, or other obstructions of similar nature. Values are given in Table 2, Chapter 13, for the average wind velocities for the months June to September in various localities throughout the United States, while Table 1, Chapter 12, lists similar values for the winter. In almost '' all localities, the summer wind velocities are lower than those in the winter, and in about two-thirds of the localities the prevailing direction is different during the summer and winter. While the tables give no average velocities below 5 mph, there will be times when the velocity is lower, even in localities where the seasonal average is considerably above 5 mph. There are relatively few places where the velocity falls below one-half of the average for many hours per month. Consequently, if the natural ventilating system is designed for wind velocities of one-half of the average seasonal velocity, it should prove satisfactory in almost every case. . Equation 3 may be used for calculating the quantity of air forced through ventilation openings by the wind, or for determining the proper size of such openings to produce given results: Q = EAV (3) where ' _ Infiltration and Air for Combustion Infiltration in buildings normally supplies the air required for combustion by fuel-burning appliances, but in some cases weatherstripping, sealing, and calking may reduce infiltra tion to the point that special openings must be provided to supply adequate air to the heating appliances. This need for combustion air is recognized in various building codes. For instance, the State Building Construction Code of New York State for One- and Two-Family Dwellings0 requires Q ~ air flow, cubic feet per minute. A * free area of inlet openings, square feet. V = wind velocity, feet per minute, = miles per hour X 88. E = effectiveness of openings. {B should be taken at 0.50 to 0.60 for perpendicular winds, and 0.25 to 0.35 for diagonal winds.)1* The precision <5f results obtained by the use of Equation 3, depends upon the placing of the openings, as the formula assumes that ventilating openings have a flow coefficient 144 CHAPTER 11 1959 Guide -- average temperature of indoor air in height h, Fahren heit. t, = temperature of outdoor air, Fahrenheit. 9.4 constant of proportionality, including a value of 65 percent for effectiveness of openings. This should be reduced to 50 percent (constant = 7.2) if conditions are not favorable. HEAT REMOVAL In problems of heat removal, knowing the amount of heat to be removed and having selected a desirable tempera ture difference, the amount of air to be passed through the building per minute, to maintain this temperature difference, can be determined by means of Equation 5. H______________________ H Q " C, X p X 60(4 - 4) " 1.08(4 -4) . 77777777777777777777^777777-777T77V7m- fig. 2 . The Jump of Wind from Windward Face of Building. (A--Length of Suction Area; B--Point of Maximum Intensity of Suction; C--Point of Maximum Pressure) slightly greater than that of a square-edged orifice. If the openings are- not advantageously placed with respect to the wind, the flow' per unit area of the openings will be less Mid, if unusually well placed, the flow will be slightly more than that given by the formula. Inlets should be placed to face directly into the prevailing wind, while out lets should be placed in one of the five places listed: 1. On the side of the building directly opposite the direction of the prevailing wind. 2. On the roof in the low pressure area causod by the jump of the wind (see Fig. 2). 3. On the sides adjacent to the windward face where low pressure areas occur. 4. In a monitor on the side opposite from the wind. 5. In roef ventilators or stacks. TEMPERATURE DIFFERENCE FORCES" The stack effect produced within a building, when the outdoor temperature is lower than the indoor temperature, is due to the difference in weight of the warm column of air within the building and cooler air outdoors. The flow due to stack effect is proportional to the square root of the draft head, or approximately Q = 9.4A VA(4 - 4) (4) tthere . Q -- air flow, cubic feet per minute. A ~' free area of inlets or outlets (assumed equal), square feet. , . - k =* height from inlets to outlets, feet. where Q *= air removed, cubic feet per minute. H = heat removed, Btu per hour. C, -- specific heat of air at constant pressure, 0.24. p density of standard air, 0.075 pounds per cubic foot. U -- 4 TM indoor-outdoor temperature differences, Fahren heit. EFFECT OF UNEQUAL OPENINGS The largest flow per unit area of openings is obtained . when inlets and outlets are equal, and the preceding equa tions are based on this condition. Increasing outlets over in lets, or vice-versa, will increase the air flow, but not in pro portion to the added area. When solving problems having an unequal distribution of openings, use the smaller area, either inlet or outlet, in the equations, and add the increase as determined from Pig. 3. ' COMBINED FORCES OF WIND * AND TEMPERATURE Equations have already been given for determining the air flow due to temperature difference and wind. It must be remembered that when both forces are acting together, even without interference, the resulting air flow is not equal to the sum of the two estimated quantities. The flow fig. 3 .... Increase in Flow Caused by Excess of One Opening Over Another (6) Infiltration and Ventilation 145 Solution for Wind Only: With 1,190 sq ft of inlet openings , distributed around the side walls, there will be about 400 sq Tt in each long side and 195 sq ft in each end. The outlet area will be equally distributed on the two sides of the monitor, or 595 sq ft on each side. With the wind perpendicular to the long side, there will be 400 sq ft of opening in its patb for inflow, and 595 in the lee side of the monitor for outflow with the wind ward side closed. The air flow, as calculated by Equation 3, will be: Q - 0.60 X 400 X 704 * 168,960 cfm. This gives 165 air changes per hour, which should be more than ample when there is no heat to be removed. Solution for Combined Heads: Since the windward side of the monitor is closed when the wind is blowing, the Sow due to temperature difference must be calculated for this condition, using Fig. 3. This chart shows that, when inlets are twice the size of the outlets, in this case 1,190 sq ft in the aide walls and 595 sq ft in the monitor, the flow will be increased 265 percent over that produced by equal openings. Using the smaller open ing and the flow per square foot obtained previously, the cal culated amount for this condition will be fig. A .... Determination of Flow Caused by Combined Forces of Wind and Temperature Difference . through any opening is proportional to the square root of the sum of the heads acting on that opening. . When the two heads are about equal- in value, and the ventilating openings are operated so as to coordinate them, the total air flow through the building is about 10 percent greater than that produced by either head acting in dependently under conditions ideal to it. This percentage decreases rapidly as one head increases over the-other. The effect of the larger head will predominate. The wind velocity and direction, the outdoor temperature, or the indoor distribution, cannot be predicted with- cer tainty, and refinement in calculations is not justified; con sequently,, a amplified method can be used. This may "be' done by using the equations and calculating the flows pro duced by .each force separately, under conditions of openings best suited for coordination of the forces. Then, by determin ing the ratio of the flow produced by temperature difference to the sum of the two flows, the actual flow due to the combined forces can be approximated from Fig. 4. - Example 1: Assume a drop forge ehop, 200 ft long, 100 ft wide, and 30 ft high. The cubical content is 600,000 cu ft, and the height of the ait outlet over* that of the inlet is 30 ft. Oil fuel of 18,000 Btu per lb is used in this'shop at the rate of 15 gph (7.75 lb per gal). Desired summer' temperature dif ference is 10 deg, and the prevailing wind is 8 mph perpendicu lar to the long, dimension, . What is the necessary area for the inlets and outlets, and wEat is.the rate of air flow through the building? * . Solution for Temperature Difference Only: The heat H -- 15 X 7.75 x 18,000 = 2,092,500 Btu per hr. By Equation 5, the air flow required to remove this heat with an average temperature difference of 10 deg is H 2 092,500 Q 193,750 cfm. 1.08(4 - 4) 1.08 X. 10 This is equal to about 20 air changes per hour. From Equa tion 4, the inlet (or outlet), opening area should be ______ Q_ _ 193,750 9.4 Vi(4 - 4) = 9.4 V30 X 10 1190 sq ft 595 X 163 X 1-265 - 122,700 cfm. Adding the two computed flows: _ Temperature Difference = 122,700 = 42 percent. Wind = 168,960 = 58 percent. Total 291,660 = 100 percent. From Fig. 4 it is determined that, when the flow due to tem perature difference is 42 percent of the total, the actual flow due to the combined forces will be about 15 times that cal culated for temperature difference alone, or 196,300 cfm. The original flow due to temperature difference alone was 193,750 cfm with all openings in use. The effect of the wind is to increase this to 196,300 cfm, even though Half of the outlets are closed. . A factor of judgment is necessary in the location of the openings in a building, especially those in the roof, where heat, smoke, and fumes are to be removed. Usually, wind ward monitor openings should be closed, but if the wind is low enough for the temperature head to overcome it, all windows may be opened. TYPES OF OPENINGS Types of openings may be classified as: (1) windows, doors, monitor openings, and skylights; (2) roof ventilators; (3) stacks connecting to registers; and (4) specially de signed inlet or outlet openings. The various types and principles of operation are discussed in following paragraphs. Windows, Doors, and Skylights Windows have the advantage of transmitting light, as well as providing ventilating area, when open. Their movable parts are arranged to open in various ways; they may open by sliding either vertically or horizontally, by tilting on horizontal pivots at or near the center, or by swinging on pivots at the top, bottom, or side. Regardless of their design, the air flow per square foot of opening may be considered to be the same under the same conditions. The type of pivoting should receive consideration from the standpoint of weather protection, and certain types may be advantageous in controlling the distribution of inanming air. Deflectors are sometimes used for the mma purpose should be considered a part of the ventilation system. Roof Ventilators The flow per square foot of inlet or outlet would be 193,750 1190 x: 1625 cfm, with all windows open. The function of a roof ventilator is to provide a storm and weatherproof air outlet. They are actuated by the 146 CHAPTER 11 1959 Guide forces of wind and temperature head that create flow through other types of openings. The capacity of a ventiiator depends upon four things: (1) its location on the roof; (2) the resistance it and the ductwork offer to. air flow; (3) the height of draft; and (4) the efficiency of the ventilator in utilizing the kinetic energy of the wind for inducing flow by centrifugal or ejector action. For maximum flow induction, a ventilator should be located on that part of the roof where it will receive the full wind without interference. If ventilators are installed within the suction region created by the wind passing over the building, or in a light court, or on a low building be tween two high buildings, their performance' will be seriously influenced. Their normal ejector action, if any, may be completely lost. The base of the ventilator should be of a taper-cone design to produce the effect of a bell-mouth nozzle whose coefficient of flow is considerably higher than that of a square-entrance orifice. If a grille is provided at the base, or if the base or structural members present obstructions, additional resistance is introduced, and the base opening should be increased in size accordingly. Air inlet openings located at lower levels in the building, should be at least equal to, and preferably larger than, the combined throat areas of all roof ventilators. The air dis charge by a roof ventilator depends on wind velocity and temperature difference, and, in general, its performance will be the same as any monitor opening located in the same place but, due to the four capacity factors already mentioned, no ample formula can be devised for expressing ventilator capacity. Roof ventilators may be classified as stationary, pivoting, or oscillating, and rotating. Generally, these have a round throat, but the continuous-ridge ventilator would fall in the stationary clarification. When selecting roof ventilators, some attention should be given to ruggedness of construction, storm-proofing features, dampers and damper-operating rpophnnigma, possibility of noise, original cost, and main tenance. Natural ventilation units may be used to supplement power-driven supply fans, and under favorable weather conditions it may be possible to stop the power-driven units. Units are not subject to code tests for ratings. Generally, they must be selected from manufacturers' tables. It is, therefore, very important to consider the reliability of the ratings used. . Controls Gravity ventilators may have dampers controlled by hnnH; thermostat, or wind velocity, in combination with a fan. The thermostat station may be located anywhere in the building, or it may be located within'the ventilator itself. The purpose of wind velocity control is to obtain a.definite volume of exhaust regardless of the natural forces, the fan motor being energized when the natural exhaust capacity falls below a certain minimum, and again shut off when the wind velocity rises to the point where this minimum volume can be supplied by natural forces. temperature difference to produce a removal of air from the rooms where the inlet openings are located. GENERAL VENTILATION RULES A few of the important considerations, in addition to those already outlined, are: 1. Inlet openings in the building should be well distributed, and should be located on the windward side near the bottom, while outlet openings are located on the leeward side near the top. Outdoor air will then be supplied to the zone to be ventilated. . 2. Inlet openings'should not be obstructed by buildings, trees, sign boards, etc., outdoors, nor by partitions indoor?. 3. Greatest flow per square foot of total opening is obtained by inlet and outlet openings of nearly equal areas. 4. In the design.of window ventilated buildings, where the direction of the wind is quite constant and dependable, the orientatioo of the building, together with amount and group ing of ventilation openings, can be readily arranged to take fiill advantage of tee force of the wind. Where the wind's direction is quite variable, the openings should be arranged in side walls and monitors so that, as far as possible, there will-: be approximately equal areas on all sides.. Thus, no matter what the wind's direction, there will always be some openings directly exposed to the pressure force, and others to a suction force, and effective movement through the building will be assured. 5. Direct short circuits between openings on two sides at a high level may clear the air at that .level without producing any appreciable ventilation at the level of occupancy. 6. In order that temperature difference may produce a motive force, there must be vertical distance between openings. That is, if there are a number of openings available in a building, but all are at the same level, there will be- no motive produced by temperature difference, no matter how great the difference might be. 7. In oider the force of temperature difference may operate to maximum advantage, the vertical distance between inlet and outlet openings should be as great as possible. Open ings in the vicinity of the neutral zone are least effective for ventilation. . *8. In the use of monitors, windows on the windward ride should usually be kept closed, since, if they are open, the inflow tendency of the wind counteracts the outflow tendency of temperature difference. Openings on the leeward side of the monitor result in cooperation of wind and temperature difference. . 9. In an industrial building where furnaces that give off heat and fumes are to be installed, it is better to locate them in the end of the building exposed to the prevailing ,wind. The strong suction effect of the wind at the roof hear the windward end will then cooperate with temperature difference. Stacks Stacks or vertical flues are really chimneys which function through the effects of the wind and temperature difference. T,ik<> the roof ventilator, the stack outlet should be located so that the wind may act upon it from any direction. With little or no wind, the chimney effect depends entirely on Tlw opening H thoM eqnal ooe-half (he hart dimension of the fho. Heovy innJafion of the Urol deck it euential. Fig. 5 .... Recommended Type of Cover for Wooden Outlet Rue Infiltration and Ventilation 147 to provide for the most active and satisfactory removal of the heat and gas-laden air. 10. In case it is impossible to locate furnaces in the wind ward end. that part of the building in which they are to be located should be built higher the rest, so that the wind, in splashing therefrom, will create a suction. The addi- tional height also increases the effect of temperature difference to cooperate with the wind. ' 11. The intensity of suction, or the vacuum produced by the jump of the wind, is greatest just back of the building face. The area of suction does not vary with the wind velocity, but the flow due to suction is directly proportional to wind velocity. 12. Openings much larger than the calculated areas are sometimes desirable, especially when an increase in occupancy may occur, or wheo extremely hot days may be anticipated. In the former case, free openings should be located at the level of occupancy for psychological reasons. 13. In single story industrial buildings, particularly those covering large areas, natural ventilation must be accomplished by taking air in arid out of the roof openings. Openings in the pressure zones can be used for inflow, and openings in the suction zone, or openings in zones of less pressure, <*>n be used for outflow. The ventilation is accomplished by the manipulation of openings to get air flow through the zones to be ventilated. VENTILATION OF ANIMAL SHaTERS11 Animal shelters require ventilation to remove moisture, . <odors and, in the case of dairy stables, excess heat. Outlets. Outlet flues for natural draft systems should be round or approximately square. A thermal resistance (1/C/) of not less than two is required in their ride walls. They should extend at least two feet above the highest part of tii roof. Only one outlet is recommended for each room or pen. The use of several outlet flues may result in ex- cessive up-drafts in some flues, and down-drafte in others. If flues have roofs or covers, these should be high enough "to provide unobstructed openings on all rides, equal in height to one-half the least dimension of the flue. Fig. 5. A level, heavily insulated ceiling under the flue roof, and over the entire area of the flue, is important. Inlets. Inlets should direct the incoming air vertically upward so as to avoid drafts on the animals, and to insure immediate mixing of incoming air with the room air. A rea sonably uniform distribution around the'stable or pen is de sirable. Inlet flues, that deliver air close to the ride walls, stimulate convection currents, which is desirable. When so placed, they also-tend to bathe the ride walls with cool air, thus reducing temperature difference between the inside and outride of the wall. - From the standpoint of air movement, insulation of inlet flues is not important. Condensation is, however, likely to occur on them, unless the thermal resistance of their walls is at least two. . Controls or throttling devices in inlet flues are seldom required. If used, they are best applied to the inlets and limited to the ride of the building facing prevailing winter winds. They should be so made that an opening, at least one inch wide by the width of the flue, will always remain open. .. Amounts- of heat and water produced by livestock vary not only with the different kinds of animals, but algo with age, weight, feed consumption, and production. These facts, and the vagaries of the weather, make exact calculations jmpossible. The following practical recommendations are based on numerous, carefully checked observations. It is desirable to keep the relative humidity of livestock shelters below 85 percent. Temperatures may be as indicated m the discussion for each kind of animal. Dairy Stables ' The most commonly accepted temperatures for dairy stables, where cows are confined in stanchions or tie stalls, are from 45 to 55 F. These temperatures are readily main tained in winter weather by the body heat of the herd in well constructed, well stocked, and well ventilated stables. Stable volume in excess of 600 cu ft, and exposed wall area in excess of 130 sq ft per 1000 lb animal weight are, in general, undesirable. ' Side walls should have an overall thermal resistance of from 2 to 5, depending on the temperature zone and wind exposure. Thermal resistance of the ceiling should be 50 percent greater than that of the ride walls. In stables of this size and so insulated, a ventilation rate of 3200 to 3800 cfh per (1000 lb of animal) usually insures good conditions. The following recommendations do not apply to so-called pen stables or loafing bams in which there is a thick manure and bedding pack on the floor, and in which doors are normally kept open. Outlets. One flue will serve a stable 200 ft long. In stables over 120 ft Jong, the flue should be about midway between the ends or, if the stable is L-shaped, near the angle. In shorter stables, it may be at any convenient location. The exhaust point in the stable should be not more than 18 in. above the floor. This permits removal of only the coolest air, and prevents rapid fluctuations in stable tem perature. A basic rule for finding the cross-section of the outlet flue is 176.Y Vh (6) where . A, ~ area of the outlet flue, square inches. N ~ weight of animal population, thousands of pounds. h . =* vertical distance from top of inlet flues to top of out let flue, feet. For large flues the flue area obtained from the baric formula may well be reduced according to the chart, Fig. 6, because of a decrease in friction. Example t: Assume a stable in which the vertical height from the top of the inlets to the top of the outlet flue is 32-5 ft, and in which 38 cows, averaging 1300 lb, will be housed. Determine required size of outlet flue. Solution: From Equation 6 . 176 X (38 X 1-300) V32J> 1525 sq. in. From Fig. 6 the factor to be applied to this area is 94.5 Fig. 6 .... Modification of Flue Area for Outlets Exceeding 1000 Sq In. 1 148 CHAPTER 11 .1959 Guide percent. Therefore, the area of fiue required is 1525 X 0.945 -- 1441 sq in. Inlets. Inlet flues, each approximately 60 sq in. in area, have given good results. One such flue should be provided for each 3500 lb animal weight. They should deliver air from points 12 to 18 in. below the ceiling. Sheep Bams Shelters used for breeding and feeding stock usually have enough openings, so that no special provision for ventila tion is required. Barns for winter lamhing flocks, however, require ventilation systems. Fermentation in the floor pack of manure produces heat, vapor, and odor. These must be added to the ventilation load regularly produced by the animals Outlet*. In practice, results obtained by the basic formula, Equation 7, when modified by the use of the chart. Fig. 6, have given good results: where A.-* Vh ' ` (7) ' A, -- area of the outlet, square inches. ' Af TM floor area, square feet. . i -. ` h - vertical height from top of inlet openings to top of outlet flue, feet. The bottom of the outlet flue should be 15 to 24 in. above the surface of the manure pack. Inlets. Provide one inlet, 60 sq in. in area, for each 150 sq ft of floor area. Inlets should be well distributed around the side walls, and designed to deliver air near the ceiling (see section on Dairy Stables). Swine Bams . .. Community swine bams, because of the extent of slop feeding and the absence of duly cleaning of the pens, are the most difficult farm buildings to ventilate.satisfactorily. Farrowing pens, to which supplemental heat is supplied, present less of a problem. In all cases, good floor drainage to remove urine and excess spilled water is important. Temperatures of from 50 to. 55 F are usually recom mended for farrowing pens. It is desirable to maintain temperatures above freezing in all other pens in community houses. For barns that are well stocked and adequately ventilated, this requires walls with an overall thermal re sistance of from 3 to 6, and ceilings with 40 to 50 percent greater resistance. Outlets. The outlet flue should draw air from a level of 15 to 18 in. above the floor. Equation 8 is the basic formula for flue area, and gives reasonably good results when modified according to the chart, Fig. 6. 5 X A, A. ' Vh (8) Inlets. At least one inlet flue should be used for each pen. Swine are given or select definite nesting places, and care must be exercised to avoid having inlets located over them. Total inlet area should be approximately 70 percent of outlet area. The area of individual inlets is best determined from the total area required, and the number that can be so installed as to meet previous specifications. Inlets should deliver air from points 12 to 15 in. below the ceiling, or from a level deflector on a sloping ceiling. Poultry Laying Houses From the standpoint of ventilation, poultry laying houses may be divided into cold houses and warm houses. The former are uninsulated, except in the. ceiling. The indoor- outdoor temperature difference is seldom more that 5 F deg. In the warm house, because of insulation or supplemental heat, the temperature seldom falls below 32 F, and is usually above 45 F. . Outlets. The outlet flue is best placed near the middle of the pen. It is advisable to limit the length of pens to 80 ft. The area of the outlet flue may be determined from Equation 9, and modified according to the chart. Fig. 6. A, Vh (9) For a cold house, the bottom of the flue should be at the level of the insulated ceiling. In warm houses, the bottom of the fiue should be 12.to 15 in. above the level of the floor litter. Inlets. Inlets may be approximately 60 sq in.- in area. The total inlet area may be equal to 70 percent of the outlet area. Inlets in cold and in warm houses should deliver air from points 12 to 24 in. above the floor. In cold houses which normally , do not have storm sash, windows may be raised enough to give the desired area, and be fitted with baffle boards to direct the air straight and upward. In houses less than 20 ft in width, all inlets may be on one side. In wider houses, a rather uniform distribution of inlets is essential. GARAGE VENTILATION Because of hazards resulting from carbon monoxide and other physiologically harmful or combustible gases or vapors in garages, the importance of proper ventilation of these buildings cannot be over-emphasized. During the warm months, of the year, garages are usually ventilated ad equately because the doors and windows are kept open. The ASHAE Code of Minimum Requirements for Heating and Ventilating Garages,1* adopted in 1935, specifies that openings for natural ventilation shall be distributed as uni formly as possible in at least two outside walls, and that the total area of such openings shall be equivalent to at least 5 percent of the floor area. The code further states that, where it is impracticable to operate such a system of natural ventilation, a mechanical system shall be used, and shall provide for either the supply of 1 cfm of outdoor air for each square foot of floor area, or for exhaust of the same amount of air, discharging it to the outdoors as a means of flushing the garage. Cooperative research11 on garage ventilation, undertaken by the ASHAE Committee on Research at Washington University, St. Louis, Mo., and at the University of and tests conducted at the ASHAE -Research Laboratory, have resulted in authoritative papers on the subject. Some of the conclusions based on work at these labora tories are: * 1. Upward ventilation results in a lower concentration of car bon monoxide at the breathing line and a lower temperature above the breathing line, than does downward ventilation for the same rate of carbon monoxide production, air change, and the same temperature at the 30-in. level. Infiltration and Ventilation 149 2. A lower rate of air change and a smaller heating load 3. In the average case, upward ventilation results in a lower concentration of carbon monoxide in the occupied portion of a garage, than that obtained with miring of the exhaust and the air supplied. However, the variations in concentra tion from point to point, together with the possible failure of the advantages of upward ventilation to accrue, suggest the basing of garage ventilation on complete mixing, ana an air change sufficient to dilute the exhaust gases to the allowable concentration of carbon monoxide. 4. The rate of carbon monoxide production by an idling car is shown to vary from 25 to 50 cfh, with an average rate of 35 cfh. 5. An air change of 350,000 cfh per idling car is required to keep the carbon monoxide concentration down to one part in 10,000 parts of air. Individual Exhaust Ducts Motor vehicle servicing areas may be provided with underground or overhead exhaust systems discharging out doors. Each service location should be provided with a flexible branch duct, the inlet end of which is sized to slip over the tail pipe of the engine, or over any deflector at tached - to the tail pipe. The minimum branch size and ventilation rate for the largest class of vehicle regularly serviced at each location are shown in Table 5. Table 5 .... Minimum Tail Pipe Connection Size and Ventilation Rate per Vehicle Ve/iide VenfiJofion Rate, elm Flexible Pipe, Dio, in. Diameter of Rigid Bmndt Connection to flexible Pipe, m. Auto up to 200 hp........ Auto or truck above 200 hp.......................... Diesel truck or bus 100 200 400 3 4 4M 4 4H Where each tail pipe exhaust branch is provided with an automatic device to dose the branch inlet when it is not in use, the capacity of the fan for the system should be based on the maximum number of branches in simul taneous use. Where the branch inlets are open when not in use, the system, capacity should be based on the total umber of branches connected to the main. Individual straight lengths of'gas tight duct, not over 20 ft in length, terminating outdoors, may be provided where exhaust systems are not installed. The duct should fit tightly over the tail pipe and be of a diameter not less than the diameter of the tail pipe. . REFERENCES 1D. R. Bahnfleth, T. D. Moseley, and W. S. Harris: ASHAE Research Repost No. 1614--Measurement of infiltration in two residences, Part I--Technique and measured infiltration (ASHAE Transactions, Vol. 63, 1957, p. 439). *D. R. Bahnfleth, T..D. Moseley, and W. S. Harris: ASHAE Research Report No. 1615--Measurement of infiltration in two residences, Part II--Comparison of variables affecting infiltra tion (ASHAE Transactions, Vol. 63, 1957, p. 453). *T. C. Min: Winter infiltration through swinging-door en trances in multi-story buildings (ASHAE Journal Section, Heating, Piping and Air Conditioning, February 1958, p. 121). *F. C. Houghten and Margaret Ingels: ASHVE Research Report No. 786--Infiltration through plastered and unplastered brick walls (ASHVE Transactions, Vol. 33, 1927, p. 377). G. L. Larson, D. W. Nelson, and.C. Braats: ASHVE Research Re port No. 828--Air infiltration through various types of brick wall construction (ASHVE Transactions, Vol. 35,1929, p. 183). G. L. Larson, D. W. Nclsuu, uui C. Braais: ASHVE Research Report No. 851--Air infiltration through various types of brick wall construction (ASHVE Transactions, Vol. 36, 1930, p. 99). G. L. Larson, D. W. Nelson, and C. Braats: ASHVE Research Report No. 868--Air infiltration through various types of wood frame construction (ASHVE Transactions, Vol. 36. 1930, p. 397). fF. C. Houghten and C. C. Schrader: ASHVE Research Report No. 686--Air leakage through the openings in buildings (ASHVE Transactions, Vol. 30, 1924, p. 105). C. C. Schrader: ASHVE Research Report No. 704--Air leakage around win dow openings (ASHVE Transactions, Vol. 30, 1924, p. 313). F. C. Houghten and M. E. O'Connell: ASHVE Research Re port No. 803--Air leakage studies on metal windows in a modern office building (ASHVE Transactions, Vol. 34, 1928, p. 321). F. C. Houghten and M. E. O'Connell: ASHVE Re search Report No. 815--Air leakage through a pivoted metal window (ASHVE Transactions, Vol. 34, 1928, p. 519). W. M. Richtmann and C. Braats: ASHVE Research Report No. 817--Effect of frame calking and storm windows on infiltration around and through windows (ASHVE Transactions. Vol. 34, 1928, p. 547). G. L. Larson, D. W. Nelson, and R. W. Kubasta: ASnVE Research Repost No. 909--Air infiltration through double-hung wood windows (ASHVE Transactions, Vol. 37, 1931, p. 571). J. E. Emswiler and W. C. Randall: The weather tightness of rolled section steel windows (ASHVE Transac tions, Vol. 34, 1928, p. 527). J. E. Emswiler and W. C. Randall: Pressure differences across windows in relation to wind velocity (ASHVE Transactions, Vol. 36, 1930, p. 83). D. O. Rusk, V. H. Cherry, and L. Boelter: Air infiltration through steel framed windows (ASHVE Transactions, Vol. 39, 1933, p. 169). `A. P. Kratz and S. Konxo: Fuel saving resulting from the use of storm windows and doors (ASHVE Transactions, Vol. 42, 1936, p. 87). 1 A. M. Simpson and K. B. Atkinson: The infiltration prob lem of multiple entrances (ASHVE Journal Section, Healing, Piping and-Air Conditioning, June 1938, p. 345). A. M. Simp son: Infiltration characteristics of entrance doors (Refrigerating Engineering, June 1936). * F. C. Houghten and J. L. Blackshaw: Indices of air change and air distribution (ASHVE Transactions, Vol. 39, 1933, p. 261). *F. C. Houghten, J. L. Blackshaw, and Carl Gutberlet: ASHVE Research Report No. 994--Wind velocities near a building and their effect on heat loss (ASHVE Transactions, Vol. 40, 1934, p. 387). F. C. Houghten and Carl Gutberlet: ASHVE Research Report No. 1069--Heating requirements of an office building as influenced by the -rtack effect. (ASHVE Transactions, Vol. 43, 1937, p. 437). H. L. Alt: Flue action in high buildings (ASHVE Journal Section, Healing, Piping and Air Conditioning, May 1932, p. 376). Axel Marin: Influence of stack effect on the heat loss m tall buildings (ASHVE Trans actions, Vol. 40, 1934, p. 377). "J. E. Emswiler: Neutral zone in ventilation (ASHVE Transactions, Vol. 32, 1926, p. 59). u State Building Construction Code Applicable to One- and Two-Family Dwellings (New York State Building Code Com mission). " W. C. Randall and E. W. Conover: Predetermining airation of industrial buildings (ASHVE Transactions, Vol. 37, 1931, p. 605). "F. L. Fairbanks: Dairy stable ventilation (ASHVE Trans actions, Vol. 34, 1928, p. 181). A. J. Offner: Cow bam ventila tion (ASHVE Transactions, Vol. 39, 1933, p. 149). For addi tional information on this subject see: M. A. R. Kelley: Technical Bulletin (U. S. Department of Agriculture, 1930). F. L. Fairbanks: Air conditioning of farm buildings (Agricul tural Engineering, November 1937, p. 485). F. L. Fairbanks and A. M. Goodman: Dairy Stable Ventilation (Cornell University, Cornell Extension Bulletin No. 151, revised 1949). F. L. Fair banks and A. M. Goodman: The Ventilation of Poultry Laying Houses (Cornell University, Cornell Extension Bulletin No. 315, revised 1950). u Code of minimum requirements for heating and ventilating garages (ASHVE Transactions, Vol. 41, 1935, p. 30). W. C. Randall and L. W. Leonhard: Airation study of garages (ASHVE Transactions, Vol. 36, 1930, p. 233). A. S. Laagsdorf 150 CHAPTER 11 1959 Guide and R. R. Tucker: ASHVE Reseabcb'Report No. 874--Carbon monoxide concentration in garages (ASHVE Transactions, VoL 36, 1930, p. 511). F. C. Houghten and Paul McDermott: ASHVE Research Repost No. 935--Carbon monoxide distri bution in relation to the ventilation of an underground ramp garage (ASHVE Transactions, Vol. 38, 1932, p. 439). F. C. Houghten and Paul McDermott: ASHVE Research Repost No. 934--Carbon monoxide distribution in relation to the ven tilation of a one-floor garage (ASHVE Transactions, Vol. 38, 1932, p. 424). F.C. Houghten and Paul McDermott: ASHVE Research Report No. 967--Carbon monoxide distribution in relation to the heating and ventilation of a one-floor garage (ASHVE Transactions, Vol. 39,1933, p. 395). A. H. Shiss, E. K. Campbell, and L. M. Farber: Carbon monoxide surveys of two garages (ASHVE Transactions, Vol. 40, 1934, p. 263). . BIBLIOGRAPHY J. B. Dick: Experimental Studies m Natural Ventilation of Houses (Department of Scientific and Industrial Research, Building Research Station Note No. 180, Garston, Watford, England). J. B. Dick: Measurement of ventilation using tracer gas technique (ASHVE Journal Section, Heating, Piping and Air Conditioning, May 1950, p. 131). C. W. Coblents and P. R. Acheabach: Design and per formance of a portable infiltration meter (ASHAB Transac tions, Vol. 63, 1957, p. 477). Garage vtotifolfcM R. R. Sayers, A. C. Fieldner, W. P. Yank and B. G. Thomas: Experimental Studies on the Effect of Ethyl Gasoline and Its Combustion Products (E/. S. Bureau of Mines Monograph No. 2, 1927). A. C. Fieldner, Yandell Henderson, J. W. Paul, R. R. Sayers, et al: Ventilation of vehicular tunnels (ASHVE Journal, January-December 1926). S. H. Ash and L. L. Naus: Use of Diesel Engines in Tunnels ((/. S. Bureau of Mines Information Circular No. 7222, 1942). L. B. Berger: Ventilation Involved in the Use of Gasoline Powered Equipment in Enclosed Spaces (U. S. Bureau of Mines Information Circular No. 7404, 1947). J. C. Holts, L. B. Berger, M. A. Elliott, and H. H. Schrenk: Diesel Engines Underground: Composition of Exhaust Gas from Engines in Proper Mechanical Condition (U. S. Bureau of Mines Report of investigations No. 3508, 1940). L. B. Berger, M. A. Elliott, J. C. Holts, and H. H. Schrenk: Diesel Engine* Underground: Use of Diesel Locomotives in Construction of the Delaware Aqueduct: Effect of Exhaust Gases upon Quality of Tunnel Air (/. S. Bureau of Mines Report of Investigations No. 4032, 1947). ' CHAPTER 12 HEATING LOAD General Procedure, Design Outdoor Weather Conditions, Indoor Temperatures, Attic Temperatures, Temperatures m Un heated Spaces, Ground Temperatures, Basement Temperatures and Heat Loss, Heat Losses from Floor Slabs, Transmission Heat Loss, Infiltration Heat Loss, Selection of Wind Speeds, Auxiliary Heat Sources, Intermittently Heated Buildings, Residence Heat Loss Problems RIOR to designing a heating system, an estimate must in amount equal to the outdoor air drawn in by the unit, the P be made of the maximum.probable heat loss of each natural infiltration losses must also be provided for by the unit. If no mechanical exhaust is used, the outdoor air supply room or space to be heated, based on maintaining a selected equals or exceeds the amount of natural infiltration that would indoor air temperature during periods of design outdoor occur without ventilation, the natural infiltration may be neg weather conditions. The heat losses may be divided into two lected. groups, namely: (1) the transmission losses or heat trans mitted through the confining walls, floor, ceiling, glas, or .9. The sum of the heat losses due to transmision (Item 6) through the outside walls and glass, as well as through any cold floors, ceilings, or roof, plus the heat equivalent (Item 7) of the other surfaces; and (2) the infiltration losses or heat required cold air entering by infiltration, or required to replace mechani to warm outdoor air which leaks in through cracks and crevices, around doors and windows, or through open doors and windows, or heat required to warm outdoor air used for ventilation. GENERAL PROCEDURE The general procedure for calculating heat'losses of a cal exhaust, represents the total heat loss equivalent for any building. 10. In buildings that have a reasonably steady internal heat release of appreciable magnitude from sources other than the heating system, a computation of this beat release under design conditions should be made for deduction from the total of the heat losses computed in items 1-9. This is especially important for heating systems of high initial cost or those for which a de mand charge is based on installed capacity. structure is: 1. Select the design outdoor weather conditions: tempera ture, wind direction, and wind speed. The data on climatic con ditions given in Tables 1 and 2 will be helpful, but should be used with judgment as suggested in the section Design Outdoor Weather Conditions. 2. Select the indoor air temperature thai is to be maintained in each room during the coldest weather. (See Table 3.) ^ 3. Estimate temperatures in adjacent unheated spaces and the attic. (See section Attic Temperatures.) The attic tempera ture need not be estimated if the combined roof and ceiling co efficient is used. 4. Select or compute the heat transmission coefficients for outside walls and glass; also for inside trails, floors, or topfloor ceilings, if these are next to unheated space; include roof if next to heated space. (See Chapter 9. If the design wind speed is appreciably different from 15 mph, the appropriate change in the neat transmission coefficients in Tables 5 to 15 erf Chapter 9 can be found in Table 20 of that chapter.) 5. Determine net area of outside wall, glass, and roof next to heated spaces, as well as any cold walls, floors, or epHingw next to unheated space. Such measurements are made from building plans, or from the actual building, tmmg made dimensions. 6. Compute the heat transmission losses for each kind of wall, glass, floor, ceiling, and roof in the building by multiplying the neat transmission coefficient in each case by the area of the surface in square feet, and the temperature difference between the indoor and outdoor air. (See Items 1, 2, and 3.) DESIGN OUTDOOR WEATHER CONDITIONS The ideal solution to the basic problem which confronts the designer of a heating system is to design a plant that has a capacity at maximum output just equal to the heating load which develops when the most severe weather conditions for the locality occur. In most cases, economics interferes with the attainment of this ideal. Studies of weather records show that the most severe weather conditions do not repeat themselves every year. If beating systems were designed with adequate capacity for the maximum weather conditions on record, there would be considerable excess capacity during most of the operating life of the system. - The weather records of principal cities of the United States1 have been analyzed to determine the probability of occur rence of certain low temperatures. The results of this analy sis appear in Table 1. Data for Canadian cities obtained by a different analytical method appear in Table 2. Five probabilities of outdoor temperatures are offered for American cities and four for Canadian cities. The analytical methods used for determining the several design temperatures cited in Table 1 for U. S. and Table 2 for Canadian cities are described in the footnotes of the tables. 7. Select unit values and compute the heat equivalent of the infiltration of cold air taking place around outside doors and windows. These unit values depend on the kind or width of crack, wind speed, and the temperature difference between the indoor and outdoor air; the result expresea the heat required to warm up the cold air leaking into toe building per hour. (See Chapter 11.) 8. When positive ventilation namp outdoor air is provided by an air heating or an air-conditioning unit, the heat required to warm the outdoor air to room temperature must be provided In many 'cases, occasional failure of a heating plant to maintain a pre-selected indoor design temperature during brief periods of severe weather is not critical. However, the successful completion of some industrial or commercial proc esses may depend upon close regulation , of indoor tempera tures. These are special cases and require extra study before assigning design temperatures. Before selecting an outdoor design temperature from by the unit; if mechanical exhaust from the room is provided, (Text continued on p. 155) 151 152 CHAPTER 12 1959 Guide Table 1 .... Winter Climatic Conditions--.United States* ._..... ^--. - .... h State A pftnI1 ........A ........A ........C Montgomery................... ........c ..,..c Yuma............................. - ........A ........c Fort Smith...................... ........A Little Rock..................... ........A IPmiulf u c......... .........A Independence..................... .....C cLos Angeles......................... ......... ...;.c .........A .........C San Jose................................ ..........C c.......... cDurango................................ ......... .........A Leadville............................... .........C Pueblo.................................... .........A Hartford................................ ..........A New Haven......................... .....A ..........C * Norwalk............................... ..........C c.......... c......... c cPensacola.. :.................... ......... Tampa............................. ........A Augusta........................... ........A ........A Savannah........................ .....A ....A Lewiston......................... ...A -Pocatello......................... ...A m................... ...C Chicago........................... ...c Peoria.............................. ..:.A Ind....................... Fort Wavne___:. /.____ Indianapolis................... Tiafayette........................ Terre Haute.......... ........ ....A ....A ....C ....A ....A Davenport...................... Dubuaue......................... Keokuk............................ Sioux City...................... ...C .. C ...c ... c ....c ....A ....C Dodge City..................... ....A teotion* ft. 610 143 293 6993 1122 199 458 257 115 331 -- 534 116 19 164 100 5398 6550 4587' 10,200 4799 15 6 15 37 23 67 24 ' 143. 356 j 48 1413 4444 601* 660 385 801 816 600 578 1023 648 805 740 637 1093 2594 Oosgn Winter Towporatero*--F froquoncy of Socvnvnco. Yoon Once to 40 6 17 11 -12 33 34 0 2 28 29 6 37 27 41 34 37 -19 -12 -11 -14 -24 -7 -5 -2 -7 50 19 32 15 14 19 -20 -24 -27 -17 -20 -13 -14 -15 -12 -28 -18 -19 -22 -21 -22 -16 Oaco n 20 Once in 13 Once la 10 Once te 5 9 12 14 18 10 12 14 18 20 22 24 27 15 18 19 . 23 -4 -2 35 36 37 36 38 39 3 39 41 -1 0 5 4 6 8 12 6 8 10 15 30 32 33 35 31 32 32 34 10 12 14 19 39 - 41 41 44 29 30 31 33 42 43 44 46 36 37 38 40 '38 38 38 39 -12 -10 -8 -6 -4 -6 -3 -1 -11 --9 -8 -18 -14 -12 -5 4 -5 -5 -1 1 4 --4 -2 1 3 -2 0 1 5 1 34 7 -3 -1 0 4 10 11 14 28 30 52 63 54 22 24 . 25 35 36 38 33 56 29 41 18 ^ 18 22 u 20 20 24 . 13 21 21 25 17 25 24 28 -10 -7 . 0 -16 -IS -8 0 -20 -17 --1.4' -7 02 -13 -11 -9 -15 -13 -11 7 -5 -6 -4 -2 3 -9 -7 -5 -2 -10 -8 -6 -1 -11 -9 -7 -2 -8 --6 -4 0 -24 -21 -20 -16 -14 -IS -10 -5 -15 -13 -12 -8 -18 -16 -14 -9 -16 -13 -11 -6 -18 -16 -15 - -11 -11 -9 -5 -11 -9 -7 -2 Ata Wind Speed, Dec, Jan, Feb1* Mpft __ - 8.0 9.9 7.5 7.7 5.4 6.7 6.7 8.3 8.3 7.3 5.4 -- 6.4 - 7.2 6.3 7.5 -- *' 7.5 5.0 4.4 11.1 7.9 10.5 8-7 9.4 9.3 . 10.5 ' 7.8 . 9.0 : 10.6. 10.9 8.6 , ^ 11.7 6.5 6.7 , 9.5 9.1 4.1 8.9 9.8 11.7 8.3 ' 9.6 10.4 11.3 11.3 10.2 7.9 10.5 10.1 7.1 8.3 11.5 7.7 10.Q Heating Load Col. 1 Table 1 .... Winter Climatic Conditions--United States* (Continued) Cot 2 . Cot 3 Col. 4 Co1. 5 Cot 6 Cot 7 Cot8 State Station** Dotalien* Ft. Design Winter Tefltpenrfinc*--F Frequency of haurcaw, Yoon One* m 40 One* in 20 One* in ?3 One* in 10 One* MS Topeka...................................... C Wichita..................................... A 991 . 1372 Ky........................ Hopkinsville.............................C Irvington.................................. C Lexington................................. A Louisville..................................C Sbelbyviile............................... C . 540 646 979 563 825 Shreveport................................A Me........................ Portland....................................A Md............ .......... 179 61 -5 0 -15 -11 -8 -7 -2 -13 -9 -6 -4 0 j -5 0 2 4 . -7 -3 0 1 -9 -5 -2 -1 -9 -5 -2 0 -9 -5 -2 0 8 6 4 4 5 ' 30 8 12 14 16 20 -15 -11 -9 -7 -3 153 Cot 9 Arg Wind Soood. Doc, tan, Febd Mp4 9.2 12.4 9.5 9.7 13.3 9.8 13.3 8.8 10.4 Mich.................. . Detroit..................................... A Fftcanaba.................................. C Grand Haven...........................C Grand Rapids.......................... C 619 645 622 706 Lansing..................................... C Ludington................................ C Marquette................................ C Sault Ste. Marie..................... A 861 650 721 721 Minneapolis............................ C Moorehead................................C St. Paul.................................... A 945 940 830 Meridian .............................. A Vieksburg................................. C Mo....................... Hannibal.:.............................. C Kansas City. .......................C St. Lonia ...............................C Springfield......... .....................A 294 316 759 741* 646 1270 Havre........................................ C Helena.......................................C Kalispell................................... A Miles City................................C Neb..................... North Platte............................A Omaha... ... ........A Valentine.................................. C Nev.:................ Winnemucca.............................C N. H......... N. J..................... Charlotteburg..:................... C Elisabeth.................................. C Flcmington.............................. C New Brunswick.......................C 2498 4175* 2965 2400 2789 . 978 2627 4293 33 134 80 --10 -10 -6 -4 -3 1 -25 -21 -18 -17 -12 -8 -5 -3 -1 2 -9 -6 -4 . -2 1 -14 -10 -8 -7 -3 -13 -9 -7 -5 -1 -22 -18 -16 -14 -10 -24 -21 -19 -17 -14 -28 -25 -23 -21 -18 -35 -32 -29 -27 -23 -28 -25 -S3 -21 -18 8 12 14 16 20 9 13 16 17 21 -19 -14 -12 -9 -4 -15 -11 -8 -6 -2 -12 -8 -5 -3 1 -12 -8 -6 -4 1 -49 -43 -39 -36 -29 -53 -44 -39 -36 -27 -43 -35 -31 -27 -19 -44 -38 -35 -32 -28 -21 -17 -15 -13 -9 -24 -19 -17 -15 -10 -27 -23 -21 -19 -15 -17 -12 -9 -6 0 -6 -3 -1 1 4 . -4 0 2 3 7 -2 1 3 5 8 -1 2 4 5 9 12.0 9.5 12.4 12.1 9.8 11.9 10.6 8.9 11.3 9.7 9.5 6.3 8.3 9.0 10.3 11.8 11.0 9.4 7.4 5.2 5.6 7.9 9.7 9.2 8.1 11.2 10.5 10.6 154 CHAPTER 12 1959 Guide Col. 1 Table 1 .... Winter CtimaKc Conditions--United States* (Continued) . Col. 2 Col. 3 Col. 4 Co1. S Col. 6 Col. 7 Cot 6 Station* N. i........................... Somerville........................................C Trenton............................................. C N. M........................ Roswell..............................................A Santa Fe........................................... C N. Y......................... Albanv........................ i....................C Binghamton.................................... C Buffalo...............................................A Canton...............................................C Ithaca.................................................C New York........................................C Oswego...............................................C Rochester......................................... A Syracuse............................................A N. C......................... Charlotte.......................................... C Hatteras............................................C Raleigh.............................................. C Wilmington......................................C N. D........................ Devils Ijftke.................................... C Grand Forks...................................C Williston........................................... C Sevufioo* Ft. 75 144 3612 7045 114 915 693 458 888 425 363 543 424 . Denys Wintnr Tetnpottilutm--F frequency of Recurrence, Yoatt Once in 40 -3 -4 -4 -2 -16 -12 -11 -28 -9 1 -12 -9 -16 Once in 20 0 0 1 1 -12 -9 -7 -25 -6 3 -9 -6 -12 Once in 13 2 2 4 3 -9 -7 -6 -22 -4 5 -7 -4 -10 Once in 10 3 3 10 6 4 -8 -5 -21 -3 6 -5 -3 -8 Once in 5 g 7 11 7 -4 -2 0 9 -1 -4 809 4 405 78 1481 832 1919 9 12 14 16 19 16 19 21 22 25 9 12 14 15 18 16 19 20 22 25 21 -37 -34 -32 -30 -27 -37 -34 -81 -30 -28 -44 -38 -35 -33 -27 Cleveland......................................... C Columbus......................................... C Dayton..............................................A Sandusky.......................................... C Toledo................................................ A 669 812 1002 608 622 -11 -7 -9 -5 -3 -2 -10 -6 -4 -2 -10 -6 -4 -2 -11 -7 -6 -4 2 2 2 0 Portland............................................C Roseburg.......................................... C Pa.............................. Harrisburg.......................................A Philadelphia...................................C Pittsburgh....................................... C Reading............................................ C Scranton........................................... C R. I........................... Kingston*.......................................... C Providence.......................................C 8. C.......................... Columbia.......................................... C Pierre.................................................. A Rapid City......................................A Knoxville......................................... A Memphis........................................... C Nashville..........................................C Tex........................... Amarillo............................................A Corpus Christ!.............................. A Dallas.................................................A 98 1 523 14 335 18 929 311 877 0 1 -9 -2 -8 100 -5 77 -4 401 14 1718 3165 -28 -28 950 -3 348 0 714 -4 3590 40 487 -10 16 1 7 10 17 19 2 4 -6 1 -4 4 6 -3 3 -2 -2 0 -1 1 17' 19 -25 -24 -22 -22 25 46 03 -5 -2 20 23 68 12 20 5 7 -2 4 -1 1 2 20 30 -21 -20 10 7 8 5 0 24 10 "if 24 2 8 11 2 8 3 10 4 5 24 17 -17 -16 14 12 13 10 5 29 15 Col. 9 Ary Wit Vttarf 11 2 10.9 73 7.0 6.8 11.3 11.2 00 7.9 9.4 91 8.6 8r 12.1 11.5 3.9 il fi 11.0 11.6 7.6 ?0 6 12.1 10 F* 8.0 10 7 8.0 77 7.2 9.3 9.8 10 1 11.0 10.6 Heating Load 155 Col. 1 State Table 1.... Winter Climatic Conditions--United States* (Concluded) Cof. 2 Col. 3 CoI. 4 Col. S Col. 6 Col. 7 Col. 8 Station* lorotten* Desyn Winter Tempercihirer*--F frequency of Recurrence, Ynars Once in 40 Once in 20 Once m 13 Once in 10 Once in S Col. 9 Ary Wind Speed, Dec, ion, feb* Me* Fort Worth......................... ......... C Galveston............................. ......... C Houston................................. ......... c Palestine............................... ......c San Antonio........................ ......... A Taylor..................................... ......... C .....C Vt.............................. Burlington........................... ......... A Northfield............................. ......... C Va.............................. Cape Henry......................... ........C Lynchburg...................... ........A Norfolk.................... ........C Richmond........................ ......c Wytheville...................... ........c .. ..c Spokane.......................... .....A Tacoma............................ ........C Tatoosh Island.............. ........c Walla Walla.................... ........c W. Va.................. Parkersburg.................... ........c 708 0 5 6 10 15 10.5 128 16 20 83 24 29 11.2 198 13 17 19 21 25 10.5 555 4 8 11 13 18 * 8.0 782 12 16 19 20 25 8.3 570 5 9 18 14 19 9.8 331 840 24 947 91 180 2400 2357 279 110 949 685 -23 -24 13 7 11 -6 -3" -19 -21 16 10 14 9 1 -17 -19 17 11 16 11 3 -15 -17 18 12 17 12 4 -11 -13 21 15 20 16 8 -28 9 12 -23 -20 13 16 -16 -16 15 18 -12 -13 16 20 -8 -5 20 25 -1 -7 -3 -1 1 5 11.6 8.8 14.0 8.1 12.1 8.1 7.3 6.2 8.0 18.9 5.3 7.2 La Crosse........................ ........c Madison.......................... ....... c Milwaukee...................... ........c Wyo..................... Cheyenne........................ ....... A Lander............................ ....... A Yellowstone Park......... ....... c 725 1008 744 6139 5569 6239 ' -27 -25 -24 -28 -39 -45 -23 -21 -20- -22 -33 -38 -20 -19 -17 -19 -30 -34 -19 -17 -15 -17 -27 -30 -14 -13 -10 -12 -21 -23 9.3 10.1 12.1 13.3 3.9 8.8 Notes for Table 1 Data compiled from U. S. Weather Bureau records by H. C. S. Thom. b Col. 2. The stations followed by letter A are airport stations; all others are city office stations and are followed by the letter C. Col. 3. Elevations marked c are ground elevations at stations. All other elevations given are the actual elevations of the ther mometer bulb above mean sea level. 4 Wind speeds are from U. S. Weather Bureau records for the period ending February 1948. The winter design temperatures*shown in Columns 4-8 inclusive for U. S. cities are minimum average daily temperatures that will recur with a probable frequency of once in the number of years shown at the head of the column based on the U. 8. Weather Bureau records for the 30-year period between 1921 and 1950. For example, the temperatures in Column 6 will recur once every 13 years as minimum average daily values, the temperatures in Column 7, once every 10 years, etc. Tables. 1 or 2, a heating engineer should consider each of the following factors: 1. Is heat capacity of structure high or low? 2. Is structure insulated? 3. Is structure exposed to high wind? 4. Is the ventilation or infiltration load high? 5. Is there more glass area than normal in the structure? 6. During what part of the day will it be used? 7. What is the nature of occupancy? 8. Will there be long periods of operation at reduced indoor temperature? . 9. What is the amplitude between maximum and minimum daily temperature in the locality? 10. Are there local conditions which cause significant varia tion from temperatures reported by Weather Bureau? ' ll. What auxiliary heating devices will there be in the build ing? . 12. What is the expected cost of fuel or energy? For the usual structure under typical conditions the ASHAE Technical Advisory Committee on Heating and Air Conditioning Loads recommends that the design tempera tures in Column 6 be used for U. S. cities. The U. S. Weather Bureau data show that an average daily temperature lower than that shown in Column 6 will occur with a probability of once in 13 years. If a careful study of preceding factors 1 to 12 shows that the indoor temperature of the structure in question will re spond more quickly than normal to extreme outdoor tem peratures that persist for less than twelve hours, then de sign temperatures from Columns 7 or 8 may be used. On the other hand, if the structure is less responsive than normal to changes in outdoor temperature, outdoor design tempera tures from Columns 5 or 4 may be selected. The designer must keep in mind, before reaching a final 156 Cof. Frov of Cenodo Cof. 2 Station* CHAPTER 12 1959 Guide Table 2 .... Winter Gimatic Conditions*--Canada Cof. 3 Co1. 4 Col. 5 Co1. 6 Cof. 7 | Cof. 8 | Cof. 9 jcoL 10 Cof. If Elevation* Period of locord* lowed Torn on fisewd* Average Annual Min. Totnp* Winter Oetign Tomp* --F Avg Wind Speed' Ft F F 1% 2H% 5%. 10% Mpfi B. c............. Edmonton................. A Grande Prairie......... A Lethbridge.................A McMurray................. A Medicine Hat............A Eetevan Point.......... C Port Nelson.............. A Penticton...................A Prince George...........A Prince Rupert...........C Vancouver................. A Victoria......................C Churchill................... A The Pas..................... A Winnipeg................... A N. B........... Nfld............ Campbellton............. C Fredericton............... C Moncton.....................A Saint John.................C Gander..................... A Goose Bay................. A St. John's.................. A N.W.T....... N.S............. Aklavik...................... C Fort Norman............C Frobisher................... A Resolute.'...................C Yellowknife...............A Halifax.......................A Sydney..................... A Yarmouth.................. A . 2219 2190 3018 1216 2365 20 1230 1121 2218 170 22 228 115 894 786 42 164 248 119 482 144 463 30 300 68 56 682 136 197 136 P. E. I....... Que............. Hamilton................... C Kapuskasing............. A Kingston.................... C Kitchener...................C London.......................A North Bay.................A Ottawa....................... A Peterborough............C Sioux Lookout.. ..;. A Sudbury..................... C Timmins.................... C Toronto...................... C Toronto...................... A Windsor..................... A Charlottetown..........C Arvida........................ C Knob Lake................ A Mont Joli...................A Montreal.................... C Montreal.................... A . Port Harrison........... C Quebec City..............C Seven Islands........... A Sherbrooke................ C Three Rivera.-.......... C Regina........................A Saskatoon.................. A Swift Current........... A Whitehorse................ A 303 752 340 1100 912 1210 339 648 1227 837 1100 379 578 637 74 375 1605 150 187 98 66 296 190 620 50 1884 1645 2677 2289 1921-1950 1942-1950 1921-1950 1921-1950 1921-1950 1924-1950 1938-1950 1921-1950 1921-1950 1921-1950 1938-1950 '1921-1950 1932-1950 1921-1950 1921-1950 1938-1950 1923-1950 1921-1950 1921-1950 1937-1950 1942-1950 1926-1950 1927-1950 1925-1950 1942-1950 1948-1950 1942-1650 1944-1950 1921-1950 1921-1950 -55 -62 -45 -64 -49 7 -61 -16 -58 -3 0 6 -50 -54 -44 -31 -38 -36 -21 -16 -35 -10 -62 -65 -49 -55 -60 -11 -23 v-11 1936-1950' 1921-1950 1921-1950 - 1921-1950 1921-1950 1925-1950 1921-1950 1921-1950 1931-1950 1921-1950 1921-1950 1921-1950 1938-1950 1921-1950 1921-1950 1932-1950 1948-1950 1943-1950 1921-1950 1942-1950 . 1942-1950 1921-1950 1944-1950 1921-1950 1921-1950 -17 -53 --31. -29 -27 -46 -38 -38 -50 -45 -22 -24 -10 -23 -42 -59 -28 -29 -28 -49 -32 -43 -39 -43 1921-1950 1921-1950 1921-1950 -54 -54 -54 1941-1950 -62 -39 -47 -32 -51 -34 22 -47 -1 -42 12 13 20 -43 -42 -35 -24 -23 -12 -10 -30 -2 -42 --54 -44 -53 -51 -9 1 -6 -42 -17. -11 -11 -33 -26 -21 -39 -34 -7 -13 -2 -n -31 -48 -16 -20 -42 -19 -24 -24 -39 -41 -34 -51 -39 -43 -38 -48 -41 14 -42 -14 -43 5 8 12 -33 -39 -32 -42 -35 17 -38 -6 -32 8 11 15 -29 -34 -28 -37 -31 21 -33 -25 12 15 19 1C -21 -27 -19 -30 -22 27 -28 -16 18 21 25 7.9 15.0 9.0 7.2 8.0 7.7 -43 -43 -33 -14 -9 -11 -6 -42 -39 -29 -11 -6 -8 -3 -40 -30 -25 -8 -3 -5 -37 -26 -21 -3 0 6.4 12.0 14.9 -6 -29 -1 -50 -46 -51 -45 -49 -3 -26 1 -46 -42 -47 -42 -47 -24 4 -43 -39 -43 -40 -45 -20 7 -39 -35 -39 -36 10.3 19.3 -3 2 5 9 12.4 -7 1 4 8 13.1 4 7 10 13 13.5 -4 -34 -15 -8 -5 -24 -18 -15 -38 -21 -30 -4 -9 0 -8 -23 -44 -14 -12 -14 0 -30 -11 -3 -20 -15 -11 -33 -17 -26 0 -4 3 -3 -19 -40 -11 -9 -11 00 5 -27 -6 2 3 -16 -11 -6 -29 -12 -22 5 1 .7 0 -16 -34 -8 -6 -8 15 10 -22 -1 7 8 -11 -7 -1 -24 -5 -17 10 6 11 e -11 -30 -3 -2 -.4 . ft 6 10.0 10.8 11.9 11.3 ii.i 8.5 - 14.1 12.1 11.3 8.2 ' 13.3 12.3 13.1 -43 -16 -23 -15 -17 -39 -12 -20 -12 -13 -35 -9 -17 -9 -10 -31 -4 -12 -5 -5 13.4 12.4 8.2 -39 -34 -30 -25 -45 -37 -33 -26 -39 -33 -29 -24 12.1 9.7 14.6 -49 -43 -37 -26 8.7 Heating Load 157 Notes for Table 2 .... Winter Climatic Conditions*--Canada * Data compiled from ihe Ciimaioiogxcal Aiiaa of Canada for ihe years indicated. b Col. 2. The stations followed by letter A are airport stations; all others are city office stations and are followed by letter C. * Col. 3. The elevations listed are ground elevations of the station. d Col. 4. The periods of record indicated apply only to the lowest temperature ever recorded shown in Col. 5, and generally extend from a summer month of the first year indicated through the spring months of the last year indicated. * Average of readings of one lowest temperature obtained for each year for period of record. For Canada, in some cases, more tfrwn one location have been used. '' ' Most of the wind speeds are based on periods ending in 1947 which are somewhat shorter than the periods for the minimum temperatures. The three months, December, January, and February were used. - * The winter design temperatures shown in columns 7*10 inclusive for Canadian cities are the Fahrenheit temperature values at or below which 1, 2H, 5, and 10 percent, respectively, of the January hourly outdoor temperatures occur for the 10 years from 1941 to 1950. The tabulated values are based on hourly temperature observations for some of the cities and upon the difference between the mean monthly temperature and the design temperature for the remainder of the cities listed. decision on outdoor design temperature, that if the indooroutdoor design temperature difference is exceeded, the indobr temperature will fall. The question is to determine how large a drop will occur and whether it can be tolerated. Finally, there is a factor, perhaps intangible, that should not be ignored. It is the performance expected by the owner from the system. In order to judge whether expected perform ance can be assured the designer needs a full understanding of the basis on which the capacities of all the system com ponents are derived or determined, the limits of accuracy of published performance data, and the accelerating capability of certain types of equipment. There is no substitute for engineering judgment in problems of this type. Judgment is developed from experience and continued study. Canadian Winter Design Temperatures - Canadian winter design temperatures are based on tem perature frequencies and show the percentage of time that the temperature might be expected to fall below certain values. Since January is nonnally the coldest month of the., winter in most of Canada, and to simplify the analysis and understanding, these values are based on January data only* In using these values to calculate the heat loss of a building, the engineer is thus designing for the coldest month of the Table 3 .... Winter Indoor Dry-Bulb Temperatures Usually Specified* ' Typo of toiktmg F Schools-- Classrooms........ Assembly rooms.................... Gymnasiums.......................... Toilets and baths................. Wardrobe and locker rooms Kitchens................ ................ Dining and lunch rooms.... Playrooms.............................. Natatoriums.......................... Hospitals-- Private rooms... 1........... Private rooms (surgical). ... Operating rooms............. Ward3. ............. Kitchens and laundries.. Toilets................ i............ Bathrooms..'............... .. . 72-74 68-72 55-65 70 65-68 66 65-70 60-65 75 72-74 70-80 70-95 72-74 70-80' Winter design temperature on a 254 percent basis is the temperature value expressed in degrees Fahrenheit at or be low which 2Zt percent of the January outdoor temperatures occur. It is suggested that this 2*4'percent basis value be normally used in Canada. However; the engineer has the opportunity of selecting the 5 or 10 percent basis value if it is not so important that the pre-selected indoor design tem perature be maintained, or on the other hand the 1 percent basis value if cost is not as important as the maintenance of indoor temperatures. INDOOR TEMPERATURES ' The indoor air temperature that must be maintained within a building is understood to be the dry-bulb temperature at the breathing line, 5 ft. above the floor, or at the seating level, 30 in. above the floor, and not less than 3 ft from the outside walls. Indoor air temperatures usually specified, vary in. accordance with the intended use of the building. Table 3 presents values that conform to good practice. The proper dry-bulb temperature to be maintained de pends upon the relative humidity and air motion, as ex plained in Chapter 6. In other words, a person may feel warm or cool at the same dry-bulb temperature, depending on the relative humidity and air motion. The optimum winter Theaters-- ' Seating space................... Lounge rooms 1...................... Toilets.................................... 68-72 68-72 68 Hotels-- '' Bedrooms and baths.......... Dining rooms........................ Kitchens and laundries..-- Ballrooms............................... Toilets and service rooms.. 75 72 66 65-68 68 Homes......................!........................ ... Stores. ....................................... Public Buldings................................. Warm Air Baths... ....................... Steam Baths......................................... Factories and Machine Shops. Foundries and Boiler Shops:*. Paint-Shops............................................. 73-75 65-68 72-74 120 no 60-65 50-60 80 * Tbe moat oomfortable dry-bulb temperature to bo maintained depends on the relative humidity and air motion. These three.factors considered together constitute what is termed the tfftclio* Umptrohm. (See Chapter 6.) When rela- tire humidity is not controlled separately, optimum dry-bulb temperature for comfort will be slightly higher than shown in Table a ' 158 CHAPTER 12 1959 Guide effective temperature for sedentary persons, as. determined at the ASHAR Research Laboratory, is 67-68 ET. - As explained in Chapter 6 for so-called still air conditions, a relative humidity of approximately 50 percent is required to produce an effective temperature of 68 ET when the dry- bulb temperature is 725 F. However, even where provision is ma/jg for artificial humidification, the relative humidity is *>tdorp maintained higher than 40 percent during the ex tremely cold weather, and where no provision is made for humidification, the relative humidity may be 20 percent or less. Consequently, in using the values listed in Table 3, consideration should be given to the actual relative humidity to be maintained, if provision is to be made for humidifica tion. If no humidification is to be provided, the higher tern-. peratures may not even produce comfort on cold days; if humidity is to be maintained at 50 percent, the lower tem peratures .will apply. . . In rooms having large glass areas, when sun is not shining, or in rooms with walls having a high heat transmission co efficient, the lowered surface temperature will cause a feeling of cnplnftsa even though the air temperature in the room is at or above thp temperatures indicated in the table. In rooms of this character, it is desirable to design for even higher temperatures than those listed, unless a compensating higher temperature surface is installed to offset the low-temperature surfaces. ' The indoor temperatures specified in Table 3 may be used for panel heated spaces as well as for spaces heated by warm air, radiators, or convectors. It is true that warm panel sur faces tend to produce a comfortable environment at a lower room-air temperature than when warm panels are not pres- ' ent, but field experience in the United States has indicated that actual reductions in air temperature are slight in opera tion. - . Temperature at Proper Level. In making the actual heat loss Computations, however, for the various rooms in a build ing it is.often necessary to modify the temperatures given in Table 3 so that the air temperature at the proper level will be used. By air temperature at the proper level is meant, in the case of walls, the air temperature at the mean height between floor and ceiling; in the case of glass, the air temperature at the mean height of the glass; in the case of roof or ceiling, the air temperature at the mean height of the roof or ceiling above the floor of the heated room; and in the case of floors, the air temperature at the floor level. Temperature at Ceiling. The air temperature at the ceiling is generally higher than at the breathing level due to stratifi cation of air resulting from the tendency of the warmer or less dense air to rise. An allowance for this fact should be made in calculating wiling heat losses, particularly in the case of high ceilings. However, the exact allowance to be made may be somewhat difficult to determine as it depends on many factors, including (1) the type of heating system, (2) ceiling height, and (3) the indoor-outdoor temperature differential. The type of hearing system is.particularly important, as the temperature gradient from floor to breathing level to ceiling may depend to a large extent on whether a direct radiation, unit heater, or warm air system is used, and in the latter, case, whether the air is moved mechanically or by gravity. The temperature of the heating medium is also a factor. It is impracticable to establish rigid rules for determining the temperature difference to use in all cases. However, for residences and structures having ceiling heights under 10 ft, the comparatively small temperature differential between the breathing leveland ceiling generally may be neglected without serious error. For higher ceilings, an allowance of approxi-. mately 1 percent per foot of height above the breathing level may be made for ceiling heights up to 15 ft and approximately Ho of 1 deg per foot of height above this level. The values in . Table 4 are calculated on this basis. For direct radiation and gravity warm air systems, the allowance should be increased from 50 percent to 100 percent over those given in Table 4. These rules should, however, be used with considerable dis cretion, as they do not apply to some types of heating systems such as those using panel and baseboard radiation, where very low temperature differences between the floor and the ceiling may exist. . Temperature at Floor Level. According to tests at the University of Illinois,* * * * the temperature at the floor level ranged from about 2 to 6 deg below that at the breathing level, or somewhat greater than the difference between the breathing level and <*iling temperatures. Tests at the Uni versity of Wisconsin* indicated a somewhat smaller differen tial between the floor and breathing level temperatures. As a general' rule, if the breathing level to ceiling temperature differential is neglected (as with ceiling heights under 10 ft), the breathing-level-to-Soor differential may also be neglected, as the two are somewhat compensating, especially where both floor and ceiling losses are calculated for the same space. In other cases, the 10 ft temperature differentials in Table 4 may be used in arriving at the floor heat loss, these dif ferentials to be subtracted from the breathing level tempera ture. ATTIC TEMPERATURES Frequently, it is necessary to estimate the attic tempera ture, and in such cases Equation 1 can be used for this pur pose: ... . A'UX + U(ArU, + A,17. + A,U,) ' A Tt ' I AT! 1 A II _L AT! where L, -- attic temperature, Fahrenheit. f = indoor temperature near top floor ceiling, Fahrenheit. t, -- outdoor temperature, Fahrenheit degrees. At " area of ceiling, square feet. .. At " area of roof, square feet. Aw * area of net vertical attic wall surface, square feet. At ~ area of attic glass, square feet. Ue 33 coefficient of transmission of ceiling, based on surface conductance of 2.20 (upper surface, see Chapter 9). - 2.20 reciprocal of one-half the air space resistance. Ur = coefficient of transmission of roof, based on surface ' conductance of 2.20 (lower surface, see Chapter 9). Uu = coefficient of transmission of vertical wall surface. U, ** coefficient of transmission of glass. . Example 1. Calculate the temperature in an unheated attic, assuming the following conditions: t = 70; = 10; A, -- 1000; A, = 1200; Am ~ 100; A,10; /, = 050; U. " 0.40; Um = 050; Ut = 1.13. -* Solution;. Substituting these values in Equation 1: ' . (1000 X 0.40 X 70) + 101(1200 X 0.50) - .+ (100 X 050) + (10 X 1.13)1 (1000 X 0.40) + (1200 X 050) + (100 X 050) + (10 X U3) 34,413 tm - 33.1 F. 1041 Equation 1 neglects the effect of any interchange. of air such as would take place through attic vents or louvers in tended to preclude attic condensation. Test data*' *'" indi- Hearing Load -159 Table 4 .... Approximate Temperature Differentials Between Breathing Level and.Ceiling, Applicable to Certain Types of Heating Systems* Brecfbmg tevcf reciperotor* (5 ft Above flood ft 60 65 70 72 74 76 79 90 ' 85 90 10 3.0 3.3 3.5 3.6 3.7 3.8 3.9 4.0 4.3 4.5 11 3.6 3.9 4.2 4.3 4.4 4.6 4.7 ' 4.8 5.1 5.4 12 4.2 4.6 4.9 5.0 5.2 5.3 5.5 5.6 6.0 ` 6.3 13 4.8 5.2 5.6 5.8 5.9 6 1 6.2 6.4 6.8 7.2 14 5.4 5.9 6.3 6.5 6.7 6.8 7.0 7.2 7.7 8.1 15 6.0 6.5 7.0 7.2 7.4 7.6 7.8 8.0 8.5 9.0 the range between the indoor and outdoor temperatures, de pending on the relative areas of the surfaces adjacent to the heated room and those exposed to the outside. If the re spective surface areas adjacent to the heated room'and ex posed to the outdoors are approximately the same, and if the coefficients of transmission are approximately equal, the temperature in the unheated' space may be assumed to be the mean of the indoor and outdoor design temperatures. If, however, the surface areas and coefficients are unequal, the temperature in the unheated space should be estimated by means of Equation 2. . ' UUiU, -f AtUt + A,Ui -f etc.) = -+ UAtUt + AtUy + AM. + etc.) . 16 6.1 6.6 ` 7.1 7.3 7.5 7.7 7.9 8.1 R.6 9.1 17 6.2 6.7 7.2 7.4 7.6 7.8 8.0 8.2 8.7 9.2 18 6.3 6.8 7.3 7.5 7.7 7.9 8.1 8.3 8.8 9.3 19 6.4 fi 9 7.4 7.6 7.8 8.0 8.2 8.4 8 9 9.4 20 6.5 7.0 7.5 7.7 7.9 8.1 8.3 8-5 - 9.0 9.5 25 7.0 7 5 8 (i 8 2 8.4 8.6 8.8 9.0 ' 9 5 10.0 30 7.5 ' 8 (1 '8.5 8.7 8.9 9.1 9.3 9.5 10.0 10.5 35 8.(1 8.5 9.(1 9.2 9.4 9:0 > 10.0 10.5 11.0 40 8.5 9.C 9.5 9.7 9.9 10 1 10.3 10.5 11.0 11 ;5 45 9.(1 9.5 10.0 10.2 10 4 10.6 10.8 11.0 11.5 12.0 50 9.5 10.0 10.5 10.7 10.9 11.1 11.3 11.5 12.0 12.5 AiUi -f A)Ut -f- AiUt + etc. ' + A.Um + A*t/ + A-cU'c + etc. where .; _* - tm = temperature in unheated space, Fahr enheit. U = indoor design temperature of heated room, Fahrenheit. i, -- outdoor design temperature, Fahren- . heit. . The figure* is thie table erebnedas eoiaaesaeof 1 percent per loot of heijbt ' ebove tin breathin* level (Aft) up to 18 ft and Me of one decree for each footibove 14 it. This table b ceoeraUy applicable to forced air type* of heatin* eyttema. direct radiation or parity warm air, iaocaae vmloea SO percent to 100 percent. Ai , At , At, etc. -- areas of surface of unheated space ad . jacent to heated space, square feet. A. , A ,- At, etc. " areas of surface of unheated space ex posed to outdoors, square feet. Ui, Ut, Ut, etc. ~ coefficients of transmission of surfaces cate reduction in temperature difference between attic air and weather is linear with attic ventilation rates between 0 and 05 cfm per sq ft of ceiling area. A ventilation rate of ' - of At , A , Ai etc. U , Ut , Ue , etc. -- coefficients of transmission of surfaces - - A. , At,, A. ; etc. 05 cfm per sq ft reduces this attic-to-weather temperature Example t: Calculate the temperature in an unheated space difference approximately 50 percent, while a ventilation rate adjacent to a heated room having surface areas (Ai, Ai, and At) of 0.1 cfm per sq ft reduces this temperature difference about' . in contact therewith of 100,-120, and 140 sq ft ana coefficients 10 percent. When attic ventilation meets the requirements (Ut, Ut, and Ut) of 0.15,050, and 055, respectively. The surface areas of the unheated space exposed to the outdoors (A. and At) of Table 3 in Chapter 10,05 cfm per sq ft is the approximate , "are respectively 100 and 140 sq ft, and the corresponding coeffi ventilation rate under design conditions. Therefore, the attic cients are 0.10 and 050. The sixth surface is on the ground and temperature found from Equation 1 above can be reduced is neglected in this example. Assume t, -- 70 and t. = -- 10. accordingly, depending upon the estimated ventilation rate. Solution: Substituting in Equation 2: However, since this affects the overall heat Loss of a residence with an insulated ceiling only one or two percent, it can be neglected without serious error. Neither does this equation take into consideration such factors as heat exchange between chimney and attic or solar 701(100 X 0.15) + (120 X 0.20) + (440 X 0.25)) : - + -101(100 X 0.10) + (140 X 050)1 (100 X 0:i5) + (120 X 0.20) + (140 X 0.25) ' - + (100 X 0.10) + (140 X 020) radiation to and from the roof. Because of these latter effects, actual attic temperatures are frequently higher , than the calculated values using Equation 1. The attic temperature may be calculated in the usual manner by means of Equa tion 1, allowing the full value of the roof. The error resulting from this assumption will generally be considerably less than if the roof were neglected (as is sometimes.the practice) and the attic temperature assumed to be the same as the outdoor ' The temperatures in unheated spaces having large glass areas and having two or more surfaces exposed to the out doors (such as sleeping porches and sun parlors), generally are assumed to be the same' as outdoors. temperature. When relatively large louvers are installed, as is customary in the southern states, the attic temperature GROUND TEMPERATURES is often assumed, as the average, between theindoor and outdoor temperatures. For a shorter, approximate method of calculating'-heat Ground temperatures to be assumed for estimating base ment heat losses usually will differ in the case of basement walls and floors, the temperatures under the floors generally losses through attics, the combined ceiling and roof coef being higher that those adjacent .to walls. Factors affecting ficient may be used, as described in Chapter 9. these temperatures will bediscussed. - TEMPERATURES IN UNHEATED SPACES The heat loss from heated rooms into unheated rooms or spaces must be based on the estimated or assumed tempera ture in such unheated spaces: This temperature will lie in Temperatures Under Basement Floors . . The temperature of the ground under basement floors0 is affected by heat sources within the basement and is not in fluenced by atmospheric conditions. In computing losses 4 160 CHAPTER 12 1959 Guide Table 5 .... Below Grade Heat Losses for Basement . ' Walls and Floors - Ground Water Tomperatuto* SosMNat Hoor lots* Mow Grade Wafl lot** fite/Sq Ft Btv/Sq Ft 40 3.0 50 2.0 60 1.0 * See Fig. 4, Chapter 41. * Baaed on temperature of 70 F and U oi 0.10 6.0 4.6 2.0 through basement floors, the ground temperatures may be assumed to be the same as water temperatures at depths of 30 to 60 ft given in Fig. 4, Chapter 41. Test observations indicate that heat losses through basement floors frequently are over-estimated.** Temperatures Adjacent to Basement Walls 1 Ground temperatures near the surface and under open spaces vary with the climate, the season of the year, and the depth below the surface. The nearer the surface (during the cold weather) the lower will be the ground temperature. Frost will penetrate to a depth of over 4 ft in some localities if not protected by snow. A. thick blanket of snow will re sult in a higher ground temperature near the surface. There fore, in localities where the ground is covered with a heavy blanket of snow throughout the winter, the ground tempera tures near the surface will be higher than when little or no snow is- present. Complete data on ground temperatures adjacent to build ings are not available, but since the recommended trans mission coefficient for basement walls in contact with the soil is only 0.10, any reasonable, assumed ground temperature will not materially affect the calculated heat loss. BASEMENT TEMPERATURES AND HEAT LOSS The allowance to be made for basement heat loss.depends on whether the basement is to be heated or not. If the basement is heated to a specified temperature, the heat loss should be calculated in the usual manner, based on the proper wall and floor coefficients (see Chapter 9) and the outdoor air and ground temperatures. Heat loss through win dows and walls above grade should be based on outdoor tem peratures and the proper air-to-air coefficients. Heat loss through basement walls below grade should be based on the floor and wall coefficients for surfaces in contact.with the- soil, and on the proper ground temperature. The heat loss values for below-grade basement'walls and floors given in Table 5 are sufficiently precise for general practice. ., If a basement is completely below grade and is not heated, the temperature in the basement .normally will range be tween that in the rooms above and the ground temperature. Basement windows will, of course, lower the basement tem- . perature when it is cold outdoors, and heat given off by the' heating plant will increase the basement temperature. In any case, the exact basement temperature is indeterminate if the basement is not heated- In general, it is found that the tran sient heat from the heating plant warms the air near the. basement ceiling sufficiently to make it unnecessary to make1 an allowance for floor heat loss from rooms located over the basement. . The temperature in crawl spaces below floors will vary widely depending on the number and size of wall vents, the amount of warm piping present and type of piping insulation. Tf. is necessary, therefore, to evaluate the conditions and to select an appropriate temperature by judgment. HEAT LOSSES FROM ROOR SLABS Two types of concrete floors used in basementless houses are (a) the unheated floor, relying for warmth on beat de livered above floor level by the heating system, and (b) the heated floor containing heated pipes or ducts that constitute a radiant slab or portion thereof for complete or partial heating of the house. -. For type (a) the floor heat los, economically considered, is of minor importance since it comprises generally about 10 percent of the total, heat loss of the house. From the comfort standpoint, however, it may be most important, since houses with cold floors are not successfully heated. In this connec tion, it should be remembered that a well insulated floor does not assure comfort if downdrafts from windows or exposed walls create pools of chilly air over considerable areas of the floor. For this, reason a floor of type (a) should not be used in a severe climate except with a heating system that delivers enough heat near the floor to counteract the downdrafts of the exterior walls and the heat transmission through the floor. The results of some experiments'** " with type (a) un heated floor slabs indicate that the heat loss from a concrete slab floor on grade is more nearly proportional to the perim eter than to the area of the floor, and that the heat loss can be estimated by means of the equation: where . * H, - FP (U - i.) (3) Hr " heat loss of the floor, Btu per hour. - P = perimeter or exposed edge of the floor, linear feet. Table 6 .:.. Heat toss of Concrete Hoors at or Near Grade Level per Foot of Exposed Edge Heating Load 161 P = heat loss coefficient, Btu per.(hour) (linear foot of ex posed edge) (degree difference in temperature between the indoor air and the outdoor air). (F ranges between Table 7____ Floor Heat Los* to be Used When Warm Air Perimeter Heating Duct* Are Embedded in Slabs* Bfo per (how) (linear foot of hooted edge) 0.81 for a floor with no edge insulation to 0.55 for a floor with edge insulation.) U = indoor air temperature, Fahrenheit. t, outdoor air temperature, Fahrenheit. In most iru^annas the values given in Table 6 for edge loss Cdgo laudation Otrfdoor Design Mn. Vortical Extend I-to. l-fype Extend 2-in. l-fype Extend Tctupeiutero, ing Down 1$ in. ing at toast 12 ing at toast 12 in. F Below Boor in. Deep and 12 ini Down and 12 io. Surface Under Under are of sufficient precision for use.*4 The insulation shown ex tending under the floor horizontally for 2 ft can also be located along the foundation wall with equal effectiveness if the insulation extends 24in. below the floor level. Example S: Calculate the heat loss from the floor of a 12 ft x 15 ft room with two exposures. The floor is an unseated con crete which is insulated at the edge with 2 in. of insulation extending horizontally for a distance of 2 ft from the edge, and the house is located in an area with an outdoor design tempera -20 -10 0 10 20 105 95 85 75 62 100 90 80 70 57 Footers include loos downward Usou|h inner area of elab. 85 75 65 55 45 ture of --15 F. Solution.* From Table 6 the heat loss per foot of exposed edge is 45 Btu per hr. The length of exposed edge is 12 ft + 15 ft -- 27 ft, r>H the total edge loss 27 x 45 = 1215 Btu per hr. = indoor temperature near surface involved (this may not necessarily be the so-called breathing-line tem perature), Fahrenheit degrees. ( = outdoor temperature, or temperature of adjacent un Floors of type (6) containing heating pipes or ducts, are - heated space or of the ground, Fahrenheit degrees. now in common use. The heat loss downward into the ground nnH outward through the edges of the floor slab is called the reverse loss. . The results1*- of an investigation in which a warm air perimeter duct was embedded in four types of concrete floorslab and foundation constructions has .verified the indication Example 4: Calculate the transmission loss through an 8-in. brick wall having an area of 150 sq ft, if the indoor temperature l. is 70 F and the outdoor temperature t. is --10 F. Solution: The coefficient of transmission U of a plain 8-in. brick wall is 0.41 (Chapter 9, Table 6). The area A is 150 sq ft. Substituting in Equation 4: that Equation 3 can be used to calculate the reverse loss when warm air perimeter heating ducts are. used. To make H, * 150 X 0.41 X 170 - (-10)1 - 4,920 Btu per hour. the results of this application more usable, values correspond ing to those shown in Table 6 for unheated floors are given Transmission Loss Through Ceilings and Roofs in Table 7 for concrete floors with a warm air perimeter duct. The desirability of edge insulation is apparent. One inch of water-resistant material is the minimum thickness of edge The transmission heat loss through top floor ceilings, attics, and roofs may be estimated by either of two methods: insulation that should be used, but a 2-in. thickness is recoin-..- mended.1** "* " The values of edge loss in Table 7 indicate that the reverse heat loss of heated dabs is likely to be about 20 percent of the total heat loss of many types of present day houses, and may exceed 20 percent if only one inch of insula tion is used at the edge of the floor. - - The concrete floor slab is usually placed on a gravel fill 4 in. thick or more, both to insulate the floor from the earth and to retard the rise of ground water by capillarity. A water proof membrane should be installed over the gravel fill. Obviously, it is important that such floors be laid several inches above grade, and that effective subsoil drainage be provided to avoid slabs soaked by rain or melting snow, and consequent excessive heat loss. - TRANSMISSION HEAT LOSS I. By substituting in Equation 4 the ceiling area A, the in door-outdoor temperature difference (l -- ) and the proper value of U: a Plat roofs. Select the coefficient of transmission of the ceil ing and roof from Tables 11 to 14, Chapter 9, or use appro priate coefficients in Equation 1 if side walls extend.appre- ciably above the ceiling of the floor below. b Pitched roofs Select the combined roof and ceiling coeffi cient from Table 15, Chapter 9 or calculate the combined roof and ceiling coefficient by means of Equations 4 and 5, Chapter 9, where these formulas are applicable as explained in Chapter 9. 2. By the attic temperature (based on the indoor and outdoor design temperatures) by means of Bouation 1, and substituting for . in Equation 4, the value of thus obtained, together with the ceiling area A and the ceiling coefficient U. This applies to pitched roofs. In the case of flat roofs it is not necessary to calculate the attic temperatures, as the ceiling-roof heat loss can be determined as suggested in preceding paragraph The basic formula for the loss of heat by transmission la. . through any surface is given in Equation 4: Hi -- AU (ti -- l)* . W INFILTRATION HEAT LOSS where The infiltration heat loss includes (1) the sensible heat loss . or the heat required to warm the outdoor air entering by Hi -- heat loss transmitted through the wall, roof, ceiling, infiltration, and (2) the latent heat loss or the heat equivalent floor, or glass, Btu per hour. A area of wail, glass, roof, ceiling, floor, or other exposed of any moisture which must be added. surface, square feet. -- Sensible Heat Loss U ~ coefficient of transmission, air-to-air, Btu per (hour) (square foot) (Fahrenheit degree temperature differ . cnce). ' ` 1 '- The formula for the heat required to warm the outdoor air which enters a room by. infiltration to the temperature 162 CHAPTER 12 1959 Guide of the room, is given in Equation'5: - H, - 0.240 Qp (U - i.) (5) where H, =* heat required to raise temperature of air leaking into . building from U to i,- , Btu per hour. 0.240 = specific heat of air. . Q *= volume of outdoor air entering building, cubic feet per hour (see Chapter 11). p " density of air at temperature L , pounds per cubic foot. It is sufficiently accurate to use p -- 0.075 in which case Equation 5 reduces to - H. - 0.018 Q (ti - t.) (5a) The volume Q of outdoor air entering per hour depends on the wind speed and direction, the width of crack or size of openings, the type of openings, and other factors, as ex plained in Chapter 11. Where the crack method is used for estimating leakage, it is more convenient to express the air leakage heat loss in terms of the crack length: H. = B L (ti - t,) (5b) where ' . B = air leakage per (hour) (foot of crack) (Chapter 11) for the wind velocity and type of windows or door crack ' involved, multiplied by 0.018. L " length of window or door crack to be taken into con sideration, feet. Example S: What- is the infiltration heat Ids per hour through the crack of a 3 x 5 ft. average, double-hung, non-weather- stripped, wood window, based on a wind speed of-15 mph? As sume indoor and outdoor temperatures to be 70 F and zero, re spectively. ' Solution: According to Table 2, Chapter 11, the air leakage through a window of this type (based on He in. crack and Hs in. clearance) is 39 cu ft per (ft of crack) (hour). Therefore, B -- 39 X OJ018 = 0.70. The length of crack L is (2 X 5) + (3 X 3), or 19 ft; t* = 70 and t, -- 0. Substituting in Equation 5b, H. = 0.70 X 19 X (70 - 0) - 931 Btu per hour. Crack Length to be Used for Computations For designers who prefer to use the crack method, the basis of calculation is as follows: The amount of crack used for computing the infiltration heat loss should be not less that half- of the total length of crack in the outside walls of the room. For a building having no partitions, air entering through the cracks on the windward side must leave through the cracks on the leeward side. Therefore, take one-half .the .total crack for computing each side and end of the building. In a room with one exposed wall, take all the crack; with two exposed walls, take the wall having the most crack; and with three or four exposed -walls, take ,the wall having the most crack; but in no case take less than half the total crack. In small residences the total infiltration loss of the house is generally considered to be equal to the sum of the infiltra tion losses of the various rooms. However, this is not neces sarily accurate as at any given time infiltration will take place only on the windward side or sides and not on the lee , ward side. Therefore, for determining the total heat require ments of larger buildings it is more accurate to base the total infiltration loss on the wall having the most total crack, but in no case on less than half of the total crack in the building. Number of Air Changes to be Used for Com putations Since a certain amount of judgment is required regarding quality of construction, weather conditions, use of room, and other factors in estimating infiltration by any method, some designers base infiltration upon an estimated number of air changes rather than upon the length of window cracks. Table 4 of Chapter 11 indicates air changes commonly used, but should be taken only as a guide. - When calculating infiltration losses by the air change method, Equation 5a may be used by substituting for Q the volume of the room-multiplied by the number of air changes obtained from Table 4, Chapter 11. For further discussion of - the method see section on Air Change Method in Chapter 11. Latent Heat Loss When it is intended to add moisture to air leaking into a room in order to maintain proper winter comfort conditions, it is necessary to determine the heat required to evaporate the water vapor added. This heat may be calculated by the equation ffi = Qp (Wi ~ W.) kf, (6) where ' Hi -- heat required to increase moisture content of air leak - ing into building from Wt to Wi , Btu per hour. Q = volume of outdoor air entering building, cubic feet per hour. p * density of air at temperature ti , pounds per cubic foot. Wi *= humidity ratio of indoor air, pounds per pound of dry air. W, = humidity ratio of outdoor air, pounds per pound of dry air. . h/$ = latent heat of vapor at Wi , Btu per pound. If the latent heat of vapor ht, is assumed to be 1060 Btu per lb, Equation 6 reduces to: Ht - 79.5 Q {Wi - W.) (6a) Equations 5a, 5b, and 6a may also be used for determining the sensible and latent heat gains due to infiltration in cool ing load computations. SaECTJON OF WIND SPEEDS The effect of wind on the heating requirements of any building should be given consideration for two reasons: 1. Wind movement increases the heat transmission of walls, glass, and roof, affecting poor walls to a much greater extent than good walls. , 2. Wind increases materially the infiltration of cold air through the cracks around doors and windows, and even through the building materials themselves (see Tables 1 and 2, Chapter H). Theoretically, as a basis for design, the most unfavorable combination of temperature and wind speed should be chosen. It is entirely possible that a building might require more heat on a windy day with a moderately low outdoor temperature, than on a quiet day with a much lower outdoor temperature. However, the combination of wind and temperature, which is the worst, would differ with different buildings, because wind speed has a greater effect on buildings which have rela tively high infiltration losses. It would be possible to compute. the beating load for a building for several different combina- Heating Load 163 tions of temperature and wind speed which records show to ' round. Table 8 shows the heat output equivalent of various have occurred, and to select the worst combination, but de sources of heat in a factory. For information concerning the signers generally do not feel that such a degree of refinement heat supplied by persons, refer to data given in Chapter 6, is justified. ' and also Table 27, Chapter 13. For appliances see Table 28, A complete correlation between the design temperatures in Chapter 13. '. Column 6 of Table 1, and the simultaneous maximum wind speed has not been made at the present time. If a designer INTERMITTENTLY HEATED BUILDINGS prefers the air change method for computing infiltration load, In the case of intermittently heated buildings additional such correlation is not too important. Designers who use the heat is required for raising the temperature of the air, the crack method may use a leakage rate at 15 mph wind speed building materials, and the material contents of the building unless local experience has established that other speeds are to the specified indoor temperature. The rate at which this more appropriate. Abnormally high wind speed may have additional heat must be supplied depends upon the heat ca significant effect on the transmission coefficient, U. (See Table pacity of the structure and its material contents, and upon 20, Chapter 9.) . the time in which these are to be heated. Exposure Factors This additional heat may be computed and allowed for as conditions require, but inasmuch'as the heating system pro Many designers use empirical exposure factors to increase the calculated heat los of rooms or spaces on the side or sides of the building exposed to the prevailing winds. However, portioned for taking care of the heat losses will usually have a capacity about 100 percent greater than that required for average winter weather, and inasmuch as most buildings may the use of exposure factors is unnecessary when THe Guide method of calculating heat losses is used. Therefore, exposure .. factors may be regarded as /actors of safety for the rooms or spaces exposed to the prevailing winds, to allow for addi . Table 6 .... Heat Equivalents of Various Sources* tional capacity for these rooms or spaces, or to balance the Machinery (Motor in room) radiation, particularly in the case of multi-story buildings. . . . _. *= Motor Hp/efficiency x 2544 Btuh Tail buildings may have severe infiltration heat losses, in Machinery (Motor outside room) = Motor Hp x 2544 Btuh duced by their stack effect (see Chapter 11), that will re Electric Lights " Kilowatts x 3413 Btuh quire special consideration. Although the exposure allowance Gas (Producer " 150) (Manufactured =* 535) frequently is amumed to be 15 percent, the actual allowance ' (Natural -- 1000) Btu/cu ft to be made, if any, must to a large extent be a matter of-ex perience and judgment of the designer, since there are at * Addition*! values Are fivn io Chapter IS, Tkble ZS. present no authentic test data available from which rules could be developed for the many conditions encountered in practice. . either be continuously heated or have more time allowed for AUXILIARY HEAT SOURCES hating Up during the few minimum temperature days, no ..allowance usually is made, except in the size of boilers or fur The heat supplied by persons, lights, motors, and machine"' naces. For churches, auditoriums, and other intermittently ery always should be ascertained in the case of theaters, as heated buildings, additional capacity should be provided. sembly halls, and industrial plants, but allowances for such heat sources must be made only after careful consideration of RESIDENCE HEAT LOSS PROBLEMS all local conditions. In many cases, these heat sources should The following Examples 6 and 7 will illustrate the proce not affect the size of the heating plant at all, although they dure for calculating the heat loss of a residence, uninsulated may have a marked effect on the operation and control of the and insulated, in accordance with the recommendations given system. In general, where audiences are present, the heating in-this chapter. system must have sufficient capacity.to bring the building to the stipulated indoor temperature before the audience ar rives. In industrial plants, quite a different condition exists, - Example 6: Calculate the heat loss of the residence shown in Fig. 1 located in the vicinity of Chicago. From Table 1, design outdoor conditions are -- 10 F and 12 mph wind speed. Indoor and heat sources, if always available during occupancy, may temperature from Table 3 is assumed to be 70 F. The attic is be substituted for a portion of the heating requirements. In unheated. Assume ground temperature to be 50 F (see Fig. 4, no case should the actual heating installation (exclusive of heat sources) be reduced below that required to maintain at. Chapter 41) under basement and garage floors and 32 F adjoin ing basement walls. Estimate infiltration losses by the air change method. No wall, ceiling, or roof insulation is to be considered least 40 F in the building. - in t.hia problem, but all first and second floor windows, except in the garage, are to have storm sash. The building is constructed Electric Motors and Machinery - as follows (heat transmission coefficients U are in parentheses): Walls: Brick veneer, building paper, wood sheathing, stud Motors and the machinery which they drive, if both are ding, metal lath, and plaster (029). Walls of dormer over ga-. located in the room, convert all of the electrical energy sup rage, same .except wood sidiDg in place of brick veneer (0.26). plied into heat. This heat is retained in the room if the prod uct manufactured is cot removed until its temperature is Attic Walls: Brick veneer, building paper, wood sheathing on studding (0.42). '* . the same as the room temperature. If power is transmitted to the machinery from the outside, then only the heat equivalent of the brake horsepower sup plied is used. In some mills this is the chief source of heating, and it is frequently sufficient to overheat the building even in Basement Walls: 10 in. concrete (0.10). Roof: Asphalt shingles on wood sheathing on rafters (0.44). Ceiling (Second Floor): Metal lath and plaster (0.74). Windows: Double-hung wood windows averaging 70 percent glass (0.45; from Chapter 9, Table 18, Section D, the U value for wood windows with storm sash is 0.53 X application factor; zero weather, thus requiring cooling by ventilation the year ' by interpolation this factor is 085). Steel casement sash in ga- 164 CHAPTER 12 1959 Guide A Boom or Spece Bedroom A and Closet Bedroom B and . Closet Bedroom C and Closet. Bedroom D and Closet Bathroom.1 . Bathroom 2 Living Room ' Dining Room Kitchen .and Entrance to Garage Lavette and .Vesti- bule - Entrance Hall ' Garage. . ' Recreation .Room* Table 9 .... Heat Loss Calculation Sheet for Uninsulated Residence (Fig. 1) B C0 E F fart of Stmdvn or InfVfrafioo Air Cbongot Walls Glass Ceiling Infiltration (34)* - Ne# Area or Air Volume 238 sq ft 40 sq ft 252 sq ft 1510 cfnk CoeffxMAf 0.29 0.45 0.74 0.018* Temp. Oiff.* 80 80 39.8d . 80 Heel Ion (flh per hour) 5520 1440 7410 2180 Walls Glass ' Ceiling Infiltration (34)* . 40 sq ft 170 sq ft 1020 cfhk 0.29 0.45 0.74 0.018* 80 80 39.8d 80 1440 5000 1470 Walla Glass Ceiling infiltration (3i)* ' , 114 sq ft 27 sq ft 129 sq ft 874 efhk 0.29 0.45 0.74 0.018* 80 80 39.8d 80 970 3800 1260 Walls Glass Ceiling Floor over garage Infiltration (34) . , 118 sq ft 20 sq ft 110 sq ft 110 sq ft 660 cfh 0.29 0.45 0.74 . 0.26 0.018* 80 80 39.8d 35* so. 2740 720 3240 950 Walls Glass Ceiling Infiltration (1)* . ' 30 sq ft 14 sq ft 55 sq ft 440 cfnk . 0.29 0.45 0.74 0.018* 80 80 39.8d . 80 690 500 1620 630 Walls 79 sq ft 0.26 Glass - . 9 sq ft 0.45 Celling 35 sq ft 0.74 Floor over garage . 35 sq ft 0.26 Infiltration (I)* 280 cfnk ' 0.018 80 80 39.8d 35* 80 1640 320 1060 320* 400 Walls ' Walls (adioining garage) Glass Floor Infiltration (l%)h . 267 sq ft 94 sq ft 50 sq ft 294 sq ft 3745 ctnk 0.29 0.39* 0.45 0.018* 80 35* 80 80 1280* 1800 5400 Walls Glass (doors) Glass (windows) Floor Infiltration OH)* . 166 sq ft 35 sq ft 20 sq ft 168 sq ft 2140 cfhk 0.29 0.85 0.45 ; 0.018* 80 80 80 80 2380 720 3080 Walls ' Walls (adioining garage) Glass Door Floor Infiltration (1H)} 51 sq ft 18 sq ft 17 sq' ft 125 sq ft 1595 cfhk 0.29 0.39* 0.45 0.51 0.018* 80 35* 80 35 80 / 700* 650 300 2300 Walls Walls-(adioining garage) , Glass * Door . Floor Infiltration (lK)k 82 sq ft 85 sq ft 9 sq ft 19 sq ft 30 sq ft 383 cfnk 0.29 0.39* 0.45 0.51 0.018* 80 35* 80 80 80 1160* 320 780 550 Walls . Door . . Ceiling' Infiltration (2)1 - - - 39 sq ft 21 sq ft . 87 sq ft 1110 cfhk 0.29 0.38 0.74 0,018* 80 80 39.8d 80 900 ' 640 2560 1600 Walls Glass . Doors Infiltration (1M)" Floor . Gain adjoining rooms 167 sq ft . 53 sq ft 44 so ft 2360 cfhk 29 ft* 0.29 1.13 0.51 0.018* 0.81 45* 45 45 45 45 2180 2700 1910 -4420* Walls . ' Glass Floor Infiltration (1)* . 220 sq ft 8 sq ft 287 sq ft 2010 cfnk 0.10 1.13 0.10 0.018* 38 80 20 80 840 2890 G Totaii (Bfu per hour) 16,550 11,530 8,680 8,610 3,440 3,740 14,680 10,030 6,170 4,710 - 5,700 4,450 5,020 TOTAL 103,310 Heating Load 165 Notes for Table 9 ... Heat Loss Calculation for Uninsulated Residence (Fig. 1) ' . . nn.c indoor-outdoor temperature difference is 70-- (--10} or 80 F except 7here otherwise noted. k Volume of infiltration, cfh = (do. air changes) x (floor or ceiling area) x (ceiling height). * From Equation Sa. - d The ceiling heat losses are calculated by estimating the attic temperature and then calculating the loss through the ceiling Rising the proper temperature difference. This unheated attic is not ventilated during winter months. The attic temperature is estimated from Equation 1 to be 30.2 F when the outdoor temperature is --10 F and room temperature is 70 F. The temperature difference is then 70--30.2 or 39.8 deg. For the insulated residence, attic temperature becomes 4.6 F and temperature difference 70--4.6 = 65.4 deg. . * Temperature in garage assumed to be 35 F. -- 1 Coefficient for wall adjoining garage calculated on basis of metal lath and plaster on both sides of studs (JJ " 0.39). * One-half of value from Table 4, Chapter 11, for storm windows or weatherstripping. k Exposed on two sides, weatherstripped windows offset by fireplace. Use 1 1 Window on one side weatherstripped but double-doors are hard to close tightly. Hence, conservative value of 1)4- 1 Assuming kitchen vent, door to vestibule usually open, allow full table value of 1H- . k One-half value in Table 4, Chapter 11, increased to 1\4 by nearby outside door in vestibule. 1 Full value in Table 4, Chapter 11, to allow for frequent opening of outside door. m Two sides exposed, large doors but large volume. Use value IK as given in Table 4, Chapter 11. - Two small unweatheratripped windows in protected location, but fireplace, indicate 1 change. * Heat losses from these rooms into garage are heat gains for garage. ' * Neglect heat loss to basement, as losses from boiler, piping, etc., will probably keep basement near, if not above, 70 F. ' Upstairs hall ceiling figures with downstairs. Heat should be provided downstairs for both. * * Linear feet of exposed edge. Fig. 1 .... Floor Plans of Residence rage and basement (1.13; from Chapter 9, Table 18, U is 1.13 for all glass and the application factor is 1X10). French doors in dining room 50percent glass, no storm doors (085; from Chapter 9, Table 18, U is 1.13.for all glass; by interpolation the applica tion factor is 0.75). Floor (Bedroom D): Maple finish flooring on yellow pine sub flooring; metal lath and plaster ceiling below (0.26). Floor (Basement and Garage): 4 in. stone concrete on 3 in. cinder concrete (0.10). ' Solution; The calculations for this problem are given in Table 9, and a summary of the results in Table 10. The values in col umn F of Table 9 were obtained by multiplying together the figures in columns C, D, and E. The heat losses are calculated to the nearest 10 Btu. See reference notes for Table 8 for fur ther explanation of data. ' Attention is called to the summary of heat losses (Table 10) for the uninsulated residence. As storm windows are used in this instance the glass and door transmission heat losses of 198 per cent are relatively small. The infiltration losses of 14.0 percent are nlgn comparatively small because the storm windows axe equivalent to weatherstripping. In this problem, the wall, ceiling, and floor transmission losses comprise 662 percent of the total. Example 7: Calculate the heat loss of residence shown in Fig. 1 based on the same conditions as in Example 6 but having construction improved or insulated to obtain coefficients as fol lows: Walls, 0.13: Walls of Dormer over Garage, 0.12; Attic Walls, 028; Walls Adjoining Garage, 0.18; Basement Walls (Recrea tion Room), 0.10. Roof, 083. Ceiling (Second Floor), 0.15. Windows (Same as in Example 6). Floor (Bedroom D), 0.18. . Solution: Hie procedure for calculating the beat losses is similar to that for Example 6. A summary of the results is given in Table 11. - 166 CHAPTER 12 1959 Guide Table 10 .... Summary of Heat Losses of Uninsulated Residence (Bfu Per Hour) Soon or Space don Walb and Root floor and Door tefif- Totals Table 11 .... Summary of Heat Losses of Insulated Residence (Bfu Per Hour) Room or Spoca Walls CdGng and Roof Boor Gfaa Door fnfif- Total* Bedroom A Bedroom B Bedroom C Bedroom D 5520 3620 2650 2740 7410 5000 3800 3240 1440 2180 16,550 1440 1470 11,530 970 1260 8,680 960 720 950 8,610 Bathroom 1 Bathroom 2 Living Room Dining Room 690 1640 7480 3850 1620 1060 500 630 3,440 320 320 400 3,740 1800 5400 14,680 3100 3080 10,030 Kitchen Lavette Entrance Hall Garage Recreation 2920 3060 900 -960* 840 2560 -1280" 950 2300 6,170 1100 . 550 4,710 640 1600 5,700 1060 3710 1910 4,440 570 720 2890 5,020 Design Totals Operating Totals* Percentages- 34,950 23,410 34,950 ^23,410 38.4 25.8 2,910 17,410 24,620 103,300 2,910 17,410 12,310 90,990 3.2 19.1 13.5 100.0 Willhot kM<rf 1180 Btiih minui vail beat gains of 1290, 700, and 1160 Btuh. * Heat gaiaa of 960 and S20 Blob. ' Baaed on H computed infilfemtion. - Baaed oa ormtipg totala. ' Bedroom A Bedroom B Bedroom C Bedroom D 2480 1620 1190 1230 2460 1660 1260 1080 1440 2180 8,560 1440 1470 6,190 970 1260 4,680 690 720 950 4,670 Bathroom 1 310 540 500 630 lj980 Bathroom 2 760 250 220 320 400 1,950 Living Room 3370 1800 5400 10,570 Dining Room 1730 3100 3080 7,910 Kitchen Lavette Entrance Hall Garage Recreation . 1320 1390 410 -470* 840 850 -910* 950 2300 4,570 1100 550 3,040 640 1600 3,500 1060 3710 1910 5,300 570 720 2890 5,020 Design Totals Operating Totals* Percentages- 16,180 7,190 16,180 7,190 29.1. 12.9 2,540 17,410 24,620 67,940 2,540 17,410 12,310 55,630 4.6 31.3 22.1 100.0 * Wall beat Ion of W0 Btiih wall beat gains of 590, 220, and 640 Btuh. b Heat gains 630and 220 Btuh. 'BaaedonHoomputed infiltration. - Baaed on operating totals. REFERENCES 1H. C. S. Thom: Revised winter outside design temperatures (ASHAE Transactions, Vol. 63, 1957, p. 111). *M. K. Thomas: A method for determining winter design temperatures (ASHAE Transactions, Vol. 61, 1955, p. 387). * A. P. Knits and 8. Kqnso: Investigation of Oil-Fired Forced Air Furnace Systems tncne Research Residence (University of Illinois, Engineering Experiment Station Bulletin No. 318). 4 A. P. Krats, W. S. Harris, M. K. Fahnestock, and R. J. Martin: Performance of a Hat-Water Heating System in the I-B-R Research Home at the University of Illinois (University of Illinois, Engineering Experiment Station Bulletin No. 349). * A. P. Krats and W. S. Harris: A Study of Radiant Baseboard Heating tn the I-B-R Research Home (University of Illinois, Engineering Experiment Station Bulletin No. 358). * W. 8. Harris: Performance of a One-Pipe Steam System in the I-B-R Research Home (University of Illinois, Engineering Experiment Station Bulletin No. 383). *G. L. Larson, D. W. Nelson, and John James. ASHVE Research Repost No. 1011--Tests of three heating systems in an industrial type of building (ASHVE Transactions, Vol. 41. 1935, p. 185). ' F. A. Joy, J. J. Zabrony, and S. Bhaduri: Insulating Value of Reflective Elements tn an Attic Under Winter Conditions (Peon* sylvsnia State University, October 1956). * F. A. Joy: Improving attic space insulating values (ASHAE Journal Section, Heating, Piping and Air Conditioning, Janu ary 1958, p. 223)! " F. B. Rowley, A. B. Aigren, and C. E. Lund: Methods of Moisture Control and Their Application to Building Construc tion (University of Minnesota, Engineering Experiment Station. Bulletin No. 17). M F. C. Houghten, S. I. Taimuty, Carl Cutberlet, and C. j. Brown: ASHVE Research Repost No. 1213--Heat loss through basement walls and floors (ASHVE Transactions, VoL 48,1942, p. 369). u R. 8. Dill, W. C. Robinson, and H. E. Robinson: Measure ments of Heat Losses from Slab Floor (U. S. Department of Commerce, National Bureau of Standards, Building Materials and Structures Report BMS 103). "H. D. Bareither, A. N. Fleming, nH B. E. Alberty: Tem perature and Heat Loss Characteristics of Concrete Floors Laid on the Ground (University of Illinois, SttioII Homes Council Technical Report). " Concrete Floors for Basementless Houses (University of - Illinois, Small Homes Council Circular No. F 43). "J. R. Jamieson, R. W. Roose, and S. Kongo: Warm-air perimeter heating. Part HI--Heat losses iroin floor rfah (ASHVE Transactions, Vol. 58,1952, p. 217). " Warm-Air Perimeter Healing (National Warm Air Heat ing and Air Conditioning Association, Manual 4). " Siab-on-Ground Construction for Residences (Building Re ' search Advisory Board, National Research Council, Publica tion No. 385). " Heat Requirement Tables for Intermittently Healed Bidd ings (A. and M. College of Texas, College Station, Texas, En gineering Experiment Station Bulletin No. 60) contains a set of tables applicable to either intermittent heating or cooling. Further information may be found in a paper byE. G. Smith: A method of compiling tables for intermittent heating (ASHVE Journal Section, Heating, Piping and Air Conditioning June 1942, p. 388). - CHAPTER 13 COOLING LOAD Cooling Load Calculations; Design Conditions; Instantaneous Heat load; Solar Radiation; Periodic Heat How; Tables for Calculating Solar Heat Gain Through Walls, Roofs, and Glass; Instantaneous Heat Gain vs. Cooling loods; Load from Inferior Partitions, Ceiling, and Floors; Load from Outdoor Air, Ventilation andInfiltration; Effect of Outdoor Air on Load; Heat Sources Within Conditioned Space; Moisture Transfer Heat Load; Miscellaneous Heat Loach; Apparatus Dew Point and Required Air Quantity Through Conditioning Equipment; Minimum Entering Air Temperature; Example Cooling Load Calculation THE variables affecting cooling load calculations are numerous, often difficult to define precisely, and always on the type of structure; (2) load due to heat gain through interior partitions, ceilings, and floors; (3) load due to ventila tion, either natural or mechanical; (4) load due to heat sources intricately interrelated. Most of the components of the cooling within the conditioned space such as people, lights, power load vary in magnitude over a wide range during a 24-hour equipment, and appliances; (5) load due to moisture transfer period, and as the cyclic changes in load components are not usually in phase with each other, careful analysis is required to establish the resultant marimnm cooling load for a building through permeable building materials; and (6) miscellaneous heat sources. C- Determination of Air Quantity and Apparatus Dew Point. or tone. A coned system must often handle peak loads in These factors will be discussed in turn. The material pre different zones at different hours. sented leads to an illustrative procedure for a cooling load Economic considerations must be of particular influence in calculation, and a numerical example is given to demon the selection of equipment for cooling season operation in strate the calculations involved. comfort air conditioning, and this fact, coupled with present inadequacies in available data and knowledge of the air DESIGN CONDITIONS conditioning art, places a premium on the experienced judg ment essential to successful design or practice. Variations in Indoor Conditions . the weather, building occupancy, and other factors affecting Indoor air conditions for human health and comfort have load, necessitate carefully coordinated controls to regulate .. been and continue to be the subject of much discussion and simultaneously the components and the equipment in order ' research. - to maintain the desired room conditions. The effective temperature index, explained in Chapter 6, is The calculation procedures presented in this chapter deal probably the best available source of design criteria for com with the various instantaneous rates of heat gain, both sen fort air-conditioning systems for buildings or enclosures in sible and latent, in a conditioned space. There may be an which the air and inside surface temperatures remain sub appreciable difference between the net instantaneous rate of stantially equal; a condition that can safely be assumed for heat gain and the total cooling load at any instant. This differ most ordinary comfort air-conditioning installations. Other ence is caused by the storage and subsequent release of heat sources of design specifications are to be found in the require by the structure and its contents. This thermal-storage effect ments of codes ordinances, and in the varied long-term may be quite important in determining an economical cooling experiences of manufacturers, contractors, and engineering equipment capacity. The lack of any adequate mftftna of specialists. . treating this storage quantitatively in its entirety for a com Past experience, cumulative over many years, indicates that plete structure, must be recognized in judging the procedures indoor design conditions, for which summer air-conditioning and data presented for calculating individual components of equipment is selected, should not exceed a temperature of tiie net rate of instantaneous heat gain. 80 F or a relative humidity of 50 percent for the average job Solar heating calculations involve the Ramp principles as in the United States. If these conditions are exceeded, com cooling load calculations. Many of the data on solar radiation plaints of discomfort may be expected, especially with con given in this chapter can be used in calculations for solar tinuous occupancy. For very brief occupancy only, a slightly heating. higher peak-load design temperature may be employed. In COOLING LOAD CALCULATIONS regard to the lower limit of humidity, complaints are not encountered for store installations operated down to 35 Summer cooling load calculations, whether for industrial or comfort applications, require consideration of the follow ing factors: A. Design Conditions: (1) indoor conditions; (2) outdoor conditions; (3) ventilation rate. B. Instantaneous Heat Load, Sensible and Latent: (1) load from solar radiation, sky radiation, and from outdoor-indopr tenmerature differential for glass areas and exterior walls and roofs, modified by periodic heat flow or lag factors depending percent relative humidity or, for office jobs, somewhat lower. These observations apply to normal commercial practice in this country only. For extremes, such as tropical or very hot regions, it is regarded as more practicable to design for a peak-lead outdoor-indoor temperature difference of about 15 to 20 F deg. Table 1 offers typical design conditions for average require ments encountered. The values in line 1 would also apply in general for localities having a summer outdoor design tem- 167 168 CHAPTER 13 1959 Guide Table 1.... Design Room Conditions Usually Specified for Summer Average Peak Load in Comfort Air Conditioning* T)>p* of btftoBotion Ory- Wei- Relative Effec BUb Mb HoaridiTy Per tive Temp rmpb Percent U>b 1. Ample capacity............ 78 65 50 72.7 72.2 2. Practical application.. 80 67. 51 78.5 74.0 3. Occupancy--15 to 40 min.............................. 82 68 49 80.0 75.3 * Value* la Table 1 are for peak lead conditions- It ia cetwtal practice to operate # eyatem at approximately 78 F asd 80 percent relative humidity at other than peak load. b Payehrwoetrio date for standard barometric preemre. * Fit. 10, Chapter 0, air movement IS to 28 (pm. perature of 90 F or less; and the 16 io 40 min occupancy values, or even somewhat higher dry-bulb temperatures, would indicate acceptable conditions for very hot localities. Table \ it to be used with good judgment, for there is no uni versal rule that may be applied to indoor design conditions. Guarantees of conditions.to be maintained for summer op eration are based upon a definite set of load conditions. At other than the guarantee load, the conditions produced by a system are determined by the balance of imposed load nnd equipment capacity, and by the method adopted for regulat ing the system operation. Complete specifications of indoor design conditions would include part-load and overload op eration, particularly from the viewpoint of economy. In the field of industrial air conditioning, indoor design conditions are established by the requirements of goods and processes, in addition to the comfort and efficiency of the workers. Many typical indoor design conditions for products in industrial air conditioning are given in Chapter 50. The load calculations for either comfort or industrial air conditioning are usually made in accordance with a guaran tee. In comfort applications, for example, this is frequently 80 F and 51 percent relative humidity or 78 F and 50 percent relative humidity. The system is normally operated at 75 or 76 F and approximately 50 percent relative humidity at all times as long as the equipment has capacity to maintain these conditions. During very hot weather, the room tem perature will rise above the control point and the equipment will operate continuously. Normally, industrial jobs are op erated at design conditions at all times if the optimum condi tions are selected for the benefit of the product. The indoor design conditions suggested have had reference to conditions to be maintained at the level of occupancy. For extremely high ceilings in public or industrial buildings, only the sons from 10 to 15 ft above the floor may be cooled to the full extent. The air temperature at the ceiling would be much higher, und this should be kept in mind when calculating the convective portion of the roof heat gain. A reduction of out- door-to-indoor air temperature differential may be assumed in such instances but radiation from the inner roof surface is not diminished. - Outdoor Conditions Summer climatic conditions and suggested design wet-bulb and dry-bulb temperatures are given in Table 2 for various locations in the United States. The highest temperature ever recorded is for the period of record shown. In some cases it should be noted that this period of record is comparatively short, and higher temperatures may be expected. In making comparisons for localities other than thnee shown in Table 2 due consideration must be given to elevation. Column 6 of Table 2 indicates the design dry-bulb tempera ture suggested by the ASHAE Technical Advisory Com mittee on Weather Design Conditions. This temperature is the maximum hourly outdoor temperature which has been equalled or exceeded 2H percent of the total hours of June, July, August, and September for the period of record, in this case tiie 5-year period 1935-1939, and should not be confused with the period of record given in Column 4 which applies only to highest temperature ever recorded. Since all of these data (Column 4) are based on airport records, they are not necessarily applicable to cities. The data given in Columns 7 and 8 were obtained from local ASHAE Chapter Secretaries, and represent the design temperatures in local use. Where such information was not available, it was taken from a publication of the AKI1 and from various other sources. The Technical Advisory Committee on Weather Design Conditions has suggested that wet-bulb design temperature be taken as that wet-bulb temperature which has beenequ&Iled or exceeded in 5 percent of the hours during months of the period of record. While not available for this edition of The Guide, due to the tremendous task of compiling these data, it is hoped that they will be available for some stations for future editions. . The wind velocity to be used in design should be that wind velocity which accompanies the design temperatures in each instance, but since these data are not available, the average summer wind velocities for the period of record were taken from U. S. Weather Bureau records revised to 1948. It is pointed out that this is not necessarily the velocity which coincides with the design temperatures, but it may serve as a guide to the designer. - Other weather data, such as daily range of temperature, are useful particularly when making cooling load calculations for an early morning peak on an east exposure. Daily range of temperature is the difference between the average of the daily maximum dry-bulb temperatures and the average of the daily minimum temperatures. This range is highest in semi- arid or desert regions and at high elevations, and lowest near the oceans or very large lakes. The daily range of temperature (Fahrenheit degrees) in July for the principal areas of the United States can be approximated from the following tabu lation: East Sea Shore.............................................................. 12 to 18 East of Mississippi River............................................ 19 to 24 Gulf Sea Shore.............................................................. 12 to 18 Great Lakes Shore........................................................ 18 to 21 Mississippi River to Rocky Mountains.................... 24 to 33 Rocky Mountain Area................................................. 33 to 42 West Coastal States..................................................... 20 to 36 West Sea Shore............................................................. 15 to 20 Ventilation Rate The introduction of outdoor air is necessary for the ventila tion of conditioned spaces. Chapter 6 suggests minimum out door air requirements for representative applications; but it is to be emphasised that minimum requirements are not necessarily adequate requirements for all psychological atti tudes and physiological responses. Where maximum economy in space and load are essential, as in submarines or other restricted spaces, as little as 1 cfm of outdoor air per person has been found to be sufficient provided that satisfactory Cooling Load 169 ventilation is simultaneously obtained by an adequate de contamination of recirculated air.1 - Local codes and ordinances frequently specify ventilation requirements for public places and for industrial installations. For operating rooms, minimum requirements for safe practice are given in a National Board of Fire ^Underwriters' pam phlet.* This pamphlet does not require 100 percent outdoor air in operating rooms, although 100 percent outdoor air is nor mally used and recommended. Recommended nd minimum ventilation rates for the most common applications are summarised in Table 3. For further general applicatipns, a bass of estimating the cfm per person may be taken as: 1. People not smoking__ 7H Recommended 5 Minimum 2. People smoking............ 40 Recommended 25 Minimum The cooling load due to the introduction of outdoor air for ventilation is determined once the indoor and outdoor design conditions are fixed. Calculations will be discussed subse quently. INSTANTANEOUS HEAT LOAD The total cooling load is frequently divided for convenience into two components, sensible heat and latent heat. While this subdivision is not imperative, past practice has found it convenient. A gain of sensible heat is considered to occur when there is a direct addition of heat to the enclosure by any one or all of the mAxhn.nisms of conduction, convection, and radiation. A gain of latent heat is considered to occur when there is an addi tion of water vapor to the air of the enclosure. For example, when the humidity in an enclosure is increased by water vapor emitted by human occupants, or by water vapor resulting from a process such as cooking, the heat required to vaporize the water does not come from the air. Maintenance of a constant humidity ratio in a sealed enclosure requires the condensation of water vapor in the cooling apparatus at. a rate equal to its rate of addition within the enclosure. The rate of heat removal from this condensing vapor would be substantially equal to the product of the rate of condensation and the latent heat of condensation; this product, expressed in Btu per hour, would be called a latent heat load. As a further example, the infiltration of outdoor air with a high dry-bulb temperature and a high humidity ratio, and the corresponding escape of room air. at a lower dry-bulb tem perature and a lower humidity ratio, would increase both the sensible heat load and the latent heat load. SOLAR RADIATION but to make an exact analysis of these phenomena is imprac ticable in air-conditioning estimates. The important principle to remember is that the total radiation I,, received by a surface at the earth, is the sum of Id and Id, where Id Klom " the direct or beamed solar radiation, Btu per (hour) (square foot of receiving surface). Id* " the direct solar radiation on a plane normal to the sun's rays, Btu per (hour) (square foot of receiving surface). Id -- the sky or diffuse solar radiation, Btu per (hour) (square foot of receiving surface). This comes prin cipally from tbs atmosphere itself as a consequence of scattering. Vertical surfaces also receive solar radiation by reflection of direct and diffuse radiation from the ground and other objects. Such radiation is usually diffuse. The diffuse radiation strikes at all angles. /, -- total incident solar radiation, Btu per (hour) (square ' foot of receiving surface). K = cosine of the angle of incidence, 0. For a vertical sur . face, 9 is defined in Fig. 1. Standardized, practical-purpose values of the direct solar radiation Id* incident upon a plane perpendicular to the sun's rays at the earth's surface, have been proposed by Moon.4 Table 4 gives these values. They are representative of a dear summer day at sea level elevation, and are nearly identical with values derived from suggested design sol-air temperatures for Lincoln, Nebraska.* Values typical of a humid industrial area derived from sol-air data for New York City* are also given in Table 4. Day-to-day changes in the amount of dust and water vapor in the atmosphere cause large differences in solar intensity values observed on cloudless days at a given locality. For example, it has been observed in Cleveland that values of the order of those given for industrial atmospheres are usually associated with dry-bulb and wet-bulb tempera tures near the design values of 95 F and 75 F (67 F dew point). On the other hand, values approaching or exceeding those for a dear atmosphere are often encountered during Cleveland summers, but with dew-point unH maximum dry-bulb tem peratures 10 to 15 deg lower. Considerable judgment, there fore, is required in selecting solar intensity values for design purposes. - Data regarding the irradiation of vertical and horizontal surfaces by diffuse or sky radiation are few. Suggested design values for a 40-deg latitude on August 1 (18-dcg declination, (Continued on p. 176) Magnitude of Solar Radiation If a plane surface were set perpendicular to the sun's rays (i.e., for normal incidence) outside the earth's atmosphere, it would receive solar radiation of about 420 Btu per (hr) (sq ft). A similarly oriented surface, at the surface of the earth, would receive considerably less solar energy because a large part of tire radiation is scattered in passing through the air,' moisture, smoke, and dust which comprise the earth's atmosphere,' and also, because some of the atmospheric constituents, notably water vapor, ozone, and carbon dioxide, absorb solar radiation. The intensity of solar radiation varies with wave length, reaching a peak at about 0.5 microns (a micron equals 1/1000 of a millimeter) and, for practical purposes, is confined to the radiation spectrum between 0.3 and 2.3 microns. The effects of scattering Mid absorption vary with the wavelength, 170 CHAPTER 13 1959 Guide Table 2 .... Summer Climatic Conditions* Suggested Design Wet*Bafb and Dry-Bulb Temperatures--F CoL 1 State CoL 2 Station* CoL 3 Deration* . ft CoL 4 Record* CoL 5 Highest Temp. Ever Recorded* F CoL 6 Design Dry-Bulb Temp. on LAC. 2H% 6ads* k n Fla......... . CO Birmingham___ ...CO Birmingham ....AP Mobile............... ...CO Mobile............... ...AP Montgomery. .. ....CO Montgomery___ ......AP Kingman ....AP Phoenix........... . ....CO Phoenix.............. ....AP ...AP Winslow............. ...CO Winslow............. ....AP Yumn................. ...CO ...CO Fort Smith........ ....AP Little Rock....... ...CO Little Rock....... ....AP ....AP Burbank............ ....AP- ...AP Eureka............... ...CO Fresno............... ...CO Fresno................ ....AP Los Angeles.... . ...CO Oakland............. ........AP Red Bluff.......... ....CO Red Bluff.......... ....AP Redding............. ...AP Sacramento....... ...CO Sacramento....... ....AP San Diego......... ....CO San Diego......... ...AP San Francisco.. . . . .CO San Jose............ ...CO Williams............ ........AP .. CO Denver............... ....... AP Durango............ ....00 ....... CO Pueblo............... ....CO Pueblo............ ...AP ...CO Hartford. , .... ....AP ...CO New Haven....... ....AP ...CO Washington....... ........AP ....CO Jacksonville___ ....CO Jacksonville.... ........AP Key West.......... ....CO Key West.......... ....AP Miami................ ....CO Miami................. ....AP Pensacola.......... ...CO Pensacola.......... ....AP Tampa............... ....CO Tampa............... ...AP Titusville.......... ....AP 711 615 143 219 293 226 3473 1122 1112 2561 4353 4899 146 463 ` 451 282 740 1925 132 387 281 534 21 305* 346 579 116 22 90 34 164 100 124 5398 5379 6558 4587* 4770 4810 20 180 17 128 20 23 104 29 23 48 253 13 67 113 111 12 52 1893-1945 1939-1947 1872-1947 . 1940-1947 1872-1947 193$-1944d 1935-1939 1895-1947 1933-1947 1935-1939 Up to 1946 1937-1947 1876-1946 1945-1947 1879-1942* 1942-1947 1931-1947* 1935-1939 1886-1947 1887-1939 1939-1947 1877-1947 1929-1947 1877-1934 1944-1947 1935-1939 1877-1947 1938-1947 1871-1940 1939-1947 1875-1947 Up to 1946 1935-1939 1934-1947 Up to 1946 Up to 1946 1889-1938 1939-1947 1940-1947 1872-1947 1943-1947 1935-1939 1871-1947 1938-1947 1871-1947 1939-1947 1896-1947 1940-1947 1879-1947 1943-1947 1890-1940 1941-1946* 1935-1939 107 103 103 104 107 103 93 107 118 117 112 107 103 120 107 110 107 111 113 85 115 111 109 102 115 112 112 114 108 110 106 101 106 116 105 104 99 105 104 104 101 98 101 94 : 106 102 104 105 100 95 96 100 103 105 98 98 98 94 92 99 107 102 95 97 94 104 103 80 ioi 79 i03 93 95 88 84 92 94 89 90 Augusta............. ....CO Augusta............. ....AP 195 424 1871-1946 1939-1947 106 105 CoL 7 Design Dry-Bulb Temp, m Coosson Use1 95 95 95 ios 105 100 iio 95 90 105 90 85'. 100 loo 85 85 91 95 95 95 . 95 93 95 95 95 95 98 91 95 95 98 CoL 8 Design Wet-Bulb Coomoo Use* 78 78 80 78 CoL 9 $Whd Velocity* Mph 5.4 8.0 65 76 6.0 72 70 78 76 6.1 78 6.2 . 70 65 74 7.9 70 5.8 65 70 72 7.9 68 65 10.7 70 64 6.9 65 65 6.8 65 75 75 7.4 78 5.9 80 78 8.4 78 79 8.7 78 78 7.4 76 7.9 76 Cooling Load 171 CoL 1 State CoL 2 Station* Table 2 .... Summer Qimatic Conditions* (Continued) Suggested Design Wet-flsdb and Dry-Bulb Temperatures--F ' CoL 3 Co. 4 CoL 5 CoL 6 Design CoL 7 CoL 8 CoL 9 Ory-Butb Dedga Design Average ftdevotion0 Period of Record* Highest Temp, tret Recorded* leap, on LAC. 2H% Dry-Bulb Temp, in Wet-Bulb Temp, in Summer Wind Velocity* F Be Common Uae( Common l/cef Mph ...CO ...AP ...CO Savannah.............. ..; AP Boise...................... ...CO ...AP ...AP Idaho Falls........... ...AP Lewiston............... ...CO ...CO Pocatello............... ...AP ...CO Chicago................. ...CO Chicago................. ...AP ...AP ...AP Springfield............ . .CO Springfield............ ...AP T,,,, TTorvo ...CO ...CO ..AP Indianapolis......... ...CO ...AP Terre Haute......... ...CO Terre Haute......... ...AP ...CO ...AP ...CO ...CO Sioux City............ ...CO Sioux City............ ...AP ...CO Dodge Citv.......... ...CO Dodge Citv........... ...AP ..CO Topeka................ ...AP ...CO Wichita................ ...AP Ky.............. Louisville.............. ...CO Louisville............ .. :ap ...CO ...AP Shreveport.'........ ...AP ...CO Portland.............. ...CO Portland.............. ...AP ...CO Baltimore............ ...AP A4inn ...AP Nantucket.......... ...CO Nantucket........... ...AP ...CO ...CO ...AP Lansing.:........... ...CO Lansing................ ...AP Marquette........... ...CO ...CO Duluth................. ...AP 408 432 115 56 2818 2849 4150 4744 763 4522 4467 319 601 615 594 660 603 608 885 970 816 800 1146 589 648 979 740 637 1093* 1098 2515 2599 991 883 1497 1423 563 544 85 8 179 100 185 65 114 43 45 45 48 615 1000 632 861 863 721 1133 1413 1899-1947 1939-1947 1871-1945* 1939-1947 1864-1939 1939-1947 1935-1939 1935-1939 1900-1944* . 1899-1947 1938-1947 1872-1947 Up to 1946 1935-1939 1932-1947 1935-1939 1879-1947 1930-1947 1911-1941* 1935-1939 1871-1946 1932-1946 1893-1946 1941-1946 . 1872-1947 1935-1939 1874-1947 1872-1946 1889-1944* 1940-1946 1885-1947 1874-1942* 1942-1947 1887-1947 1946-1947 1888-1939 1939-1947 1871-1947 1937-1947 1874-1947 1937-1947 1935-1939 1873-1947 1885-1940 1940-1947 1871-1947 1935-1939 1870-1935 1936-1947 1886-1947 1946-1947 1873-1933 1934-1947 1910-1947 1940-1947 1874-1947 1941-1947 105 102 105105 112 109 104 100 117 105 103 106 105 107 106 111 110 109 108 106 107 . 106 107 110 103 111 111 110 113 111 108 116 109 109 114 108 114 109 107 103 102 100 109 93 103 99 110075 104 101 92 82 104 104 105 102 98 108 106 95 93 95 94 88 92 92 94 94 96 89 9i 95 ioo 93 93 98 9i 87 89 95 * 78 95 78 95 65 95 95 98 95 96 96 98 95 95 95 95 95 95 95 95 95 95 95 ioo ioo 95 95 ioo 90 90 95 92 95 95 95 95 - 93 93 65 65 78 75 76 76 77 78 75 76 78 78 78 78 78 78 78 78 78 75 78 80 78 70 73 78 75 75 75 75 73* 75 73 73 8.0 5.8 9.5 8.2 7.0 '8.9 8.6 11.8 7.2 6.9 7.0 8.7 7.4 12.5 9.5 172 CHAPTER 13 1959 Guide Table 2 _____Summer Gimatic Conditions* (Continued) Siroaested Otttnn Wef-Bufi) and Dry-Bulb Temperatures--f CoL 1 State CoL 2 Station* CoL 3 CoL 4 CoL 5 CoL 6 Oesign Elevation* ft Highest Temp. Period at Record* Ever Recorded* F Dry-Bulb Temp, on T.A.C. 214% Basis* CoL 7 Design Dry-Bulb leap, tn Common Um1 CoL 8 CoL 9 W*f-8u/b Summer Wind Velocity* Common Use1 Mph ...CO Minneapolis........ ...AP St. Paul................. ...CO St. Paul............... ...AP 873 951 708 1938-1947 1871-1933 1937-1947 ' 104 104 104 91 ...CO Meridian............... ...AP Vicksburg............. ...CO Vicksburg.............. ...AP 298 316 266 1939-1947 1874-1947 1941-1947 105 104 - 104 ...CO Columbia.............. ...AP Kansas City....... ...AP St. Louis............... ...CO St. Louis............... ...AP Springfield............ ...AP 787 780 646 597 1270 1939-1947 1935-1939 1871-1947 1930-1947 1935-1939 102 112 110 111 105 ioi 97 96 Mont........ Billings.................. ...AP Butte..................... ...AP Havre.................... ...CO Helena................. ...CO Kaiispell............... CO Miles City............ ...AP 3584 5538 2498 4175 3004 2629 1935-1947 1931-1947 1880-1947 1880-1940. - 1897-1947 1935-1939 106 100 108 103 101 108 . 92 85 97 ...CO Lincoln.................. ...AP North Platte........ ...CO North Platte.. ...AP Omaha. . . . ..CO On-ifthe ...AP Valentine.............. ...CO 1185 2815 2788 1219 1009 2627 1933-1947 1874-1947 1935-1939 1873-1935* 1935-1947 1889-1947 115 109 109 111 114 110 ioi 98 98 ...AP Las Vegas............. ...AP Reno...................... ...CO Reno...................... ...AP Winnemucca......... ...CO 1882 4588 4417 4293 1937-1947 1905-1942 1940-1947 1871-1947 117 106 105 1108 108 93 .. CO Concord................. ...AP 359 1941-1947 99 ...CO Camden___ '......... ...AP Newark..........'.... ...AP Trenton................. ...CO N. M........ Albuquerque........ .:.coj Albuquerque......... ...AP E! Morro............... ...AP Rodeo.................... ...AP Roswell....-........... ...CO Tucumcari............ ...AP 20 15 144 5022 5319 7120 4116 3643 4054 1935-1939 1931-1947 1886-1946 1931-1933* 1933-1947 - 1935-1939 1935-1939 1905-1947* 1935-1939 105 104 106 99 101 92 101 107 107 9i 89 93 84 97 97 N. Y......... .. CO Albany................... ...AP 280 1938-1947 99 88 bmghamton......... ..CO 915 1891-1946 103 Binghamton.......... ...AP 836 1942-1947 97 ...AP 726 1935-1939 95 86 Canton.................. CO 458 1906-1947 99 Elmira................... ...AP 948 ' 1935-1939 96 88 New York............. ..CO 425 1871-1947 102 Oswego.................. ..CO 363 1871-1947 100 Rochester.............. ..CO 609 1872-1947 102 Rochester.............. ...AP 560 1935-1939 98 ` 89 Syracuse............... ..CO 465 1902-1940 102 Syracuse................ ...AP 404 1940-1947 97 88 N. C......... Charlotte:............. ..CO Charlotte.............. ...AP Greensboro........... ...AP 809 757 896 1878-1947 1939-1947 1928-1947 103 103 101 93 91 95 ` * 95 95 95 100 ioo 95 90 95 95 95 . 95 95 95 iis 95 95 95 95 95 95 95 93 95 93 90 95 93 95 93 95 95 75 79 78 78 78 66 70 67 65 78 78 78 75 65 65 73 78 75 78 70 70 75 75 73 73 75 73 75 75 78 78 10.2 4.6 6.4 9.1 9.5 8.7 8.1 9.7 8.1 7.2 4.9 8.8 . 7.8 7.5 12.1 8.2 12.'5 - 5.6 Cooling Load 173 CoL 1 Slate CoL 2 Station* Table 2 .... Summer Climatic Conditions* (Continued) Suggested Design Wf-6ub and Dry-Bulb Teaperuhms--F CoL 3 Elevation* ft CoL 4 CoL 5 CoL 6 Design Period of Record* Highest Temp. Ever Recorded* F Dry-Bulb Temp, on 7-AC. 2K% Bods* CoL 7 Design Dry-Bulb Temp, in Commoo l/se* C0L8 vfeHbib Temp, in Common Use* CoL 9 Average Sommer Wind Vehdty* Mfdt N. C......... 95 78 6.3 Raleigh................ ...AP 446 1944-1947 T02 93 Wilmington.......... ...CO 78 1871-1947 103 95 78 8.4 95 73 9.5 Bismarck............. ...AP 1655 1940-1947 109 96 Devils Lake......... ...CO 1481 1904-1947 112 95 70 Dickinson........... ...AP 2599 1935-1939 112 94 Fargo..................... ...AP 900 1935-1939 115 93 95 75 Pembina.............. ...AP 830 1935-1939 109 92 Williston............... ...CO 1919 1879-1947 no 95 73 Cincinnati............. ...CO 772 1870-1947 Cincinnati........... ...AP 488 1931-1947 Cleveland............. ...CO 669 1871-1946 Cleveland............ ...AP 813 1930-1946 Columbus............. ...CO 812 1878-1946 Columbus.............. ...AP 820 1939-1947 Dayton.................. ...CO 1086 . 1883-1943* Dayton.................. ...AP 1002 1940-1947 Sandusky.............. CO 608 1878-1946 Toledo................... ...CO 668 1871-1947 Toledo................. ...AP 626 1940-1947 108 108 100 107106 100 108 -99 105 105 100 94 90 90 9i 95 78 6.6 95 75 11.1 95 76 95 78 95 75 95 75 Oklahoma City... ...CO Oklahoma City... ...AP Tulsa ........... ...AP Waynoka............... ...AP 1264 1311 686 1529 Baker.................... ...CO Baker.................... ...AP Eugene.................. ...CO Eugene.................. ...AP Medford................ ...CO Medford................ ...AP Portland............... ...CO Portland................ ...AP Roseburg:............. ...CO Pa........... Erie........................ ...CO Erie........................ ...AP Harrisburg............ ...AP Philadelphia......... ..CO Philadelphia......... . . .AP Pittsburgh.......... -. ..CO Pittsburgh............ ...AP Reading................. ...CO Scranton............... ...CO Sunbury................ ...AP R. I.......... Providence........... ..CO S. C.......... Charleston............ ...AP Columbia.............. ..CO Columbia.............. ...AP 8. D.......... Huron.................... ...AP Rapid City........... ...CO Rapid City........... ...AP 3501 3374 366 368 1428 1343 98 25 523 771 736 339 200 18 929 1284 311 877 448 77 51 401 227 1287 3309 3220 Chattanooga......... . .AP Knnrville.............. ...CO Knoxville.............. ...AP 675 1024 1007 1890-1947 -1939-1947 1932-1947 1935-1939 1889-1947 1939-19471890-1942 1942-1947 1911-1929 1929-1947 1874-1947 1940-1947 1877-1947 1873-1946 1935-1939 1935-1939 1871-1947 1940-1947 1875-1947 1935-1947 1913-1947 1901-1947 1935-1939 1904-1947 1940-1947 1887-1947 1939-1947* 1938-1947 1888-1947 1939-1947 1940-1947 1871-1942* 1942-1947 113 109 109 115 104 103 104 105 no 115 107 105 109 98 96 103 106 100 103 102 105 103 101 100 103 106 104 no 106 108 105 104 102 99 100 103 95 90 88 95 87 85 91 88 89 91 94 94 ioi 77 ioi 77 96 . 66 90 68 95 70 90 68 90 66 93 75 95 95 78 95 75 95 75 . 95 75 93 75 95 95 75 95 75 95 70 95 76 95 75 9.8 6.5 9.7 8.9 9.5 10.3 7.9 5.6 6.7 174 CHAPTER 13 1959 Guide CoL 1 State CoL 2 Table 2... .Summer Gimotic Conditions* (Continued) Suggested Design Wet-Bulb and Dry-Bidb Temperatures--F CoL 3 ft CoL A CoL 5 CoL 6 Design Period of Uncord* Highest Temp Ever Recorded* Dry-Bulb Temp, on LAC. 2>*% Basts* CoL 7 Oes'gn Ory-fiufb Jump, in Common Use1 CoL 8 Design Wet-Bulb Temp, in Common Use1 CoL 9 Average Summer Wins Velocity* Mpfi CO Memphis.............. ...AP 267 1872-1941* 1941-1947 106 105 96 95 78 N ashvilla.............. ...CO Nashville............. ...AP 714 610 1871-1947 1939-1947 106 104 95 78 Texas....... Abilene................ ...CO Abilene................ ...AP Amarillo ..CO Amarillo.............. ...AP Austin................... ...CO Austin.................. ...AP Brownsville.......... ...CO Brownsville......... ...AP Corpus Christi... ...CO Corpus Chnsti... ...AP Dallas.................... ...CO Dallas.................... ...AP Del Rio................. ..CO El Paso................. ...CO El Paso................. ...AP Fort Worth.......... ...CO Fort Worth......... ...AP Galveston............. ...CO Galveston............. ...AP Houston................ ...CO Houston................. ...AP Palestine............... ...CO Port Arthur......... ...CO Port Arthur.......... ..:AP San Antonio......... ...CO San Antonio......... ...AP Waco...................... ...AP Wink...................... ...AP 1748 1756 3686 3595 625 625 140 25 21 45 732 520 1020 3792 3956 708 728 128 9 198 73 555 64 21 770 800 513 2811 1885-1944* 1949-1947 1892-1941 1941-1947 1897-1942 1942-1947 1922-1943* 1943-1947 1887-1942 1943-1946 1913-1940 1940-1947 1905-1947 1887-1942 1939-1947 1898-1939 1940-1947 1871-1947 1939-1947 1888-1947 1932-1947 1881-1947 1917-1947 1944-1947 1885-1941* 1942-1947 1931-1947 1935-1939 111 107 106 109 104 102 105 101 no 109 111 106 104 112 no 101 101 108 105 108 102 98 107 104 111 no 100 74 97 ioo 72 11.s 100 78 ioo 80 95 ioo 78 9.3 ioo 100 97 ioo 78 8.4 95 95 93 8.8 95 79 ioo 98 78 7.8 99 Utah........ Milford.................. ...AP Modena................. ...CO Salt Lake City. .. ...CO Salt Lair* City. .. ...AP 5095 5472 4346 4Z54 1935-1939 1901-1947 1874-1947 1928-1947 103 a 101 105 106 ' 94 95 95 65 9.8 Vt.............. Burlington............ ...AP 335 1884-1943* 1943-1947 100 101 90 73 85 Va............. Lynchburg............ .CO Lynchburg............ ...AP 24 644 951 1874-1947 1874-1944 1944-1947 104 106 100 95 78 95 Norfolk................. ..CO 91 1871-1947 105 Richmond............. ...CO Richmond............. ...AP 180 172 1897-1947 1929-1947 . 107 104 95 78 Roanoke................ ...AP 1194 1935-1939 103 90 95 76 Wash........ Ellensburg............ ...AP 1731 1935-1939 ' . 105 90 North Head......... ..CO 199 1884-1947 97 85 Seattle................... ..CO 104 1890-1947 100 85 65 Seattle................... ...AP `47 1928-1947 99 si Spokane ........ ..CO Spokane................. ...AP 2030 1974 1881-1941* 1941-1947 . 108 104 92 93 65 6.5 Tacoma................. ..CO 279 1897-1947 98 85 64 Tatoosh Island ... ..CO no 1883-1947 88 Yakima................. .CO Yakima ..AP 1160 1066 1928-1946 1944-1947 no 103 95 65 W. Va....... Parkersburg......... CO 685 1888-1947 106 95 75 5.2 598 1886-1947 104 95 75 9.2 La Crosse . ..CO La Crosse.............. ...AP Madison................ ..CO Madison.................. ..AP 725 677 1008 884 1872-1947 1943-1947 1858-1947 1935-1939 108 96 107 106 91 95 75 95 75 7.9 95Milwaukee............. ..CO Milwaukee.............. ..AP 744 707 1870-1947 1927-1947 105 106 87 75 9.8 Cooling load CoL 1 state CoL 2 Station* 175 Table 2... .Summer Climatic Conditions* (Concluded) Suggested Design Wet-Bulb end Dry-Buib Temperatures--F Col. 3 ftBevutioo* CoL A CoL 5 Period of Record* Highest Temp. Ever Recorded* F CoL 6 Design Dry-Bulb Temp, oo IAC. 2<A% Basis* Col. 7 Design Dry-Bulb Temp, m Common Use1 CoL 8 Col.? Wei-iLb Average Summer Wind Velocity* Common Use* Mph ...CO 1873-1935 100 95 65 9.2 Cheyenne............... . .AP 6161 1935-1947 100 89 ...CO 5448 1891-1946 102 95 65 ...AP 5568 1936-1947 97 Rock Springs___ ...AP 6746 1932-1942 98 87 Summer Climatic Conditions for Canada1 Col. 1 Prov. of Conodo* Col. 2 Station1* CoL 3 Col. A ftElevation* Period of Record* CoL 5 Highest Temp, on 8ecordk f CoL 6 CoL 7 CoL 8 CoL 9 Summer Design Temp. 1--F 1% 2% 5% 10% CoL 10 Design D6 Temp, m Common Use1 CoL 11 Design WB Temp, in Common Use* CoL 12 Avg. Summer Wind Vetodfy- AV* Edmonton.............. AP AP AP .AP .AP 3540* 2219* 2365* 22* 1921-1950 1921-1950 1921-1950 1938-1950 1921-1950 97 99 106 87 108 86 S3 80 77 87 83 80 77 92 89 86 82 80 77 75 72 89 86 84 81 Sydney.................... CO no .CO .AP 119* 83* 197* 1921-1950 102 1921-1950 93 1921-1950 94 1921-1950 ' 95 89 87 84 81 80 77 76 72 80 78 76 73 85 83 80 75 .AP 1921-1950 104 85 82 79 76 AP 1210* 1925-1950 99 83 80 77 74 Ottawa.................... AP 339* 1921-1950 102 89 86 84 81 CO 635* 1921-1950 99 83 80 77 74 no 379* 1921-1950 .105" 88 86 83 81 Toronto.................. ..AP 578* 1938-1950 101 90 87 84 81 P.E.I.......... Charlottetown...... Saskatoon.............. no co AP .CO .AP .AP 74* 98* 296* 1645* 1921-1950 1942-1950 1921-1950 1921-1950 98 97 96 96 111 104 82 79 77 74 87 84 82 79 88 85 83 80 85 82 80 77 88 85 81 92 89 85 81 90 90 90 80 90 90 90 90 93 93 90 90 90 90 66 9.7 68 8.9 65 9.1 67 7.8 71 11.5 75 7.9 75 6.6 9.9 8.4 9.6 75 8.9 75 75 8.1 8.7 8.7 75 9.9 9.5 75 9.0 71 12.4 70 10.7 Notes for Table 2 * Detn eampQed from U. 8. Weather Bureau Data and various other sources. b Column 2, The station deauumtion AP or CO indicates airport or eity office station, respectively. * ndumn s. The devotions marked e ere (round elevations of the station. All other elevations oven are the actual elevations of the thermometer bulb above mean sea level, corrected to IMS. * The periods of reeard indicated apply only to the highest temperature ever recorded shown in Column 5, and do not necessarily include all of the summer months of the first year indicated. The last year indicated includes July or August, except three marked d which terminate prior to July of that year. * It should be noted that rviumn 6 in the United States section of the table applies only to airports, as these data for city stations are not available at this Ume. The temperature shown is the maximum hourly outdoor temperature which has been equalled or exceeded SH percent of the total hours of June, July. August, and September for the 6-year period 1936-1939 inclusive. It is pointed out that in most cases the airport statuna are outside of the city, and that tbicaa data would apply primarily to rural areas. 1 Columns 7 and 8 in tt United States section and Columns 9 and 10 in the Canadian section of the table record wet- and dry-bulb temperatures in use by ASHAE members as reported by Chapter secretaries (or various stations Where such values were uot available, the design temperatures published by API or obtained from various other sources have been inserted. ' * Tbs average wind velocities in Column 9 in the United States section were furnished by the U. S. Weather Bureau, corrected to 1948. In general these velocities are averages for the months of June through September. t The bulletin published by ARHAK for the """! weather data of Detroit indicates 73 F as the design wet-bulb temperature which has been equalled or ex ceeded 5 percent of the hours for period 1939-39. 1 (paces indicate data not available. 0 . I The data for were compiled by D- W. Boyd and Moriey Thomas from the records of the Meteorological Diviridn, National Research Council of Canada. k The bigtast temperature ever recorded in the section of the table is for the 39-year period, 1921-1990, where available. In some eases the stations have been relocated and in a few instances, some years are missing. 1 In the section of the table, tha summer design dry-bulb temperatures for the basis of 1, 3H, 5, and (0 percent are the Fahrenheit temperature values at or above which these percentages of all the July hourly outdoor temperatures occur, for the years 1941-1950 tadumve. " Mnatrrf tk ti-H tr*e*** im hewd nn t fin periodleading in 1947 which arc somewhat shorter than the periods far the highest, temperatures. The three months June, July, and August were used. , 176 CHAPTER 13 1959 Guide Table 3 .... Outdoor Air Requirements* Application Smoking Cto per Person* .ra per Sq'Ffof Hoar g |1 MM(Wint* Minimum* Apartment Banking space............... Occasional__ 10 Barber shops................. Considerable. 15 Beauty parlors.............. Occasional__ 10 Brokers' board rooms.. Very heavy. -. 50 Corridors (supply or Directors' rooms........... Extreme......... 50 Drug stores*.................. Considerable 10 10 Five and Ten Cent Hospitals Operating rooms'*.. None___..... Kitchens ^. Laboratories*................. Some............... 20 Meeting room* Offices Very heavy... 50 7H 10 7M 20 30 ZH 0.05 0.10 7M 1.0 2.0 0.33 25 6.33 2.0 15 30 1.25 Private........................ Considerable - 30 Cafeteria*................... Considerable . 12 Dining room*............. Considerable . 15 Schoolrooms4................ None............... 25 10 12 0.25 Qnrrva Toilets4 (exhaust)........ 2.0 * Taken From prtaeni-day practice. ' ^ This B err * When mlwlmnni g USed, tekS lei jei gf peg. 4 See bad codes which may govern. ' * May be governed by exhaust. 1 Hay be governed by speedl sources of contamination or local codes. * All outside air recommended to overcame exploebn basard of aamtimtica. See Notional Boari of fin Uuderwrittn' PanjMei No. 56. - (Continued from p. 169) - north) are given in Table 4 for the two types of atmospheres. These are based upon observations made on cloudless days in Cleveland over a period of several summers. Since less ex tensive data were available for industrial atmospheres, there is more uncertainty regarding these values. In both instances, the values include an unknown amount of ground reflection, which may be expected to vary with location. It should be noted that clouds which do not obscure the sun tend to increase diffuse radiation values. Nearby hniMinga may reduce diffuse irradiation by partial shading. Calculation Tables The irradiation of a surface by the sun is the product of /p , tiie direct normal radiation (see Table 4), and the wxin K of the incident angle $. Forhorizontal surfaces, the cosine K equals the sine of the solar altitude. For vertical walls, K is a function of the solar altitude 0 and the wall solar azimuth y, thus . K * cos 0 = cos p cos y (1) These three angles are defined in Fig. I. Values of K are given in Table 5 and values of 0 and y are given in Table 6 for 18-deg north declination (August 1). To compute K values for orientations other than those given in Table 5, third angle <(>, the solar azimuth t is required. In this discussion, <f> will be measured east from south in the morning, and west from south in the afternoon. Hence, <t> values are equal to 90 deg minus the y values for an east or west facing wall, except when Table 6 shows the south walls to be in the shade. In this case ^ equals 90+7, that is, 0 is greater than 90 deg. The wall azimuth \p is the angle, measured east from south to the perpendicular to the wall for walla which have an easterly component, and west from south for those having a westerly component. For example, yp for a wall facing north east is 135 deg. Hie wall solar azimuth y may be found according to the following schedule: For walls facing east of south: For walls facing west of south: y ~ d -- i> a.m. . y - d + f a.m. y * $ + t P-m. y -- 4 -- i pjn. Treat negative values of 7 as if they were positive. If 7 is greater than 90 deg, the wall is in the ghaHo * Values of K for other seasons and latitudes may be found in the literature,7 or may be computed from data given in Hydrographic Office Bulletin No. 214, Tables of Computed Altitude and Azimuth? and the Ephemeris of the Sun.* Table 7 shows the variation of solar declination during the months ordinarily requiring cooling. Example 1: Find the solar azimuth at 6:30 p.m. at 40-deg north latitude on August 1. Solution: From Table 6:in the column of y for a wall facing west 4 for 6:00 p.m. is 90 + 14 * 104 deg, and at 7:00 p-m. is 90 + 24 ** 114 deg. By interpolation, 4 for 6:30 pjn. is 109 deg west of south (at 5:30 a.m. * would be 109 deg east of south). Example B: Find K for a wall facing 18 deg east of south at 10:00 a.m. on August 1 at 50-deg north latitude. Solution: The wall azimuth is 18 deg. The solar azimuth is 48 deg east (Table 6). The wall solar azimuth is 48 -- 18 or 30 deg. From Table 6,0 is 50 deg. Then K - cos & cob y = cos 50 X cos 30 = 0.643 X 0.866 0.557. Example 8: find K for the wall in Example B at 3:00 pan. Solution: The solar azimuth is 65 deg west. The wall solar azimuth is therefore 65 + 18 83 deg. The angle p is 42 deg. K - cos 42 X cos 83 - 0.743 X 0.122 - 0.091. Example 4: Find the total solar irradiation for the wall for the conditions of Example B. . Solution: Use clear atmosphere solar intensities. At 50-deg altitude, the direct normal radiation is 273 Btu per (hr) (so ft). Then, Id - K X Id* - 0.557 X 273 - 152.0 Btu per (hr) (sq ft). Cooling Load . 177 Table 4____ Values of , Direct Solar Radiation Received at Normal Incidence at the Earth's Surface, and Values of U, Diffuse or Sb* Solar Radiation, Received by Variously Oriented Surfaces tUo per.(hoar) (square foot) Solar Attitude P, O* greet Direct* radiation AM - l 5 10 15 20 25 30 35 40 45 50 60 70 80 90 67 123 166 197 218 235 248 258 266 273 283 289 292 294 For Clear Atmosphere* Diffuse or sky radiation^** N E S W ' Horiz. ' Detect4 normal radiation 6 11 4 4 11 20 8. 7 14 27 11 10 15 32 13 12 16 35 15 13 17 36 17 15 17 36 19 16 18 36 21 17 19 35 23 18 19 33 25 19 21 28 27 21 _ _ _ _22 23 29 23 -------- 7 14 19 23 26 28 30 31 32 33 34 35 . -- -- 34 58 80 103 121 136 148 158 165 172 181 188 195 200 For Industrial Atmospheres Diffuse or sky radiation**' * NE s w Horiz. 4 11 5 3 8 22 9 7 11 28 13 9 13 36 17 12 16 43 21 16 18 47 24 18 19 50 27 21 20 50 30 23 21 49 31 25 22 47 34 27 22 41 37 30 22 34 41 34 ---- -- -- ---- -- -- 9 18 24 31 38 44 . 48 52 55 58 63 69 -- -- PM --* Nw S E Horiz. NW S E Horiz. * Moon'*4 propueed standard for ana level. SO mm predpitable water vapor, S00 dual particle* per en cm, S.8 mm Hg partial pressure of oxone. b For 40 deg north latitude on about August 1. . * Rserifi ir* *tii nntinm try ftRtran Laboratory at Cleveland an doodles* day* daring whieb the observed normal incidence value* closely approximated the normal ineideaee value* tabulated. 4 Derived from recommended design sal-sir temper*tares4 for New York City For a borisoatal surface with absorptivity of 1.0. - latitude 30 Deg north Table 5____ Values of K, the Cosine of the Incident Angle, for Variously . Oriented Walls and a Horizontal Surface ' Computed for 16 Oeg-Oedmefion, North (Augur# I) Sun Time Cosine JC of Oe Incident Angle AM --4 i 6 pjn. 75 84 93 N 0.267 0.144 0.030 NE 0.862 0.752 0.604 0.427 E 0.952 0.919 0.824 0.672 SE 0.484 0.548 0.561 0.524 $ 0.068 10 11 . 12 2 1 0.234 0.039 0.476 0.246 0.000 0.438 0.310 0.147 0.144 0.192 0.208 7 p.m. 66 75 84 0.406 0.237 0.079 0.934 0.840 0.705 0.533 0.914 0.951 0.919 0.824 0.358 0.505 0.594 0.631 0.069 93 10 2 11 1 12 ` 0.337 0.129 0.673 0.475 0.246 0.000 0.614 0.542 0.424 0.265 0.196 0.292 0.354 0.375 66 7S 84 0.385 0.199 0.010 0.922 0.813 0.656 0.465 0.920 0.951 0.918 0.824 0.378 0.532 0.643 0.700 0.166 9' 10 ; 11 12 3 2 1 t PM - 0.252 0.030 0.673 0.475 0.247 * 0.000 0.699 0.642 0.532 0.375 0.316 0.433 0.505 0.530 w *-NW w SW . $ SW 0.147 0.076 0.265 0.183 0.376 SE Horiz. 0.156 0.367 0.566 0.737 0.866 0.951 0.978 0.009 0.199 0.391 0.568 0.713 0.829 0.903 0.927 0.078 0.233 0.399 0.545 0.669 0.766 0.829 0.848 Horiz. 178 Latitude 30 Deg north 40 Deg north 50 Deg north CHAPTER 13 1959 Guide Table 6 .. . Values of the Wall Solar Azimuth, y, for Variously Oriented Walls and Solar Altitude - Computed for 18 Dog Declination, North (August I) * Sao fisw Solar Altitude P Degrees Azimuth Angie y, Pegreei AM -+ 1 6 &.m. 7 8 9 6 pjn. 5 4 3 10 2 11 1 12 5 a.m. 6 7 8 7 p.m. 6 5 4 93 10 2 11 1 12 5 a.m. 6 7 8 7 p.m. 6 5 4 93 10 2 11 1 12 9.0 21.5 34.5 47.5 60.0 72.0 78.0 0.5 11.5 23.0 34.5 45.5 56.0 64.5 68.0 4.5 13.5 23.5 33.0 42.0 50.0 56.0 58.0 N- KE 74 81 88 Shade 66 ' 76 85 Shade 29 36 43 51 62 83 Shade 21 31 40 . 50 61 76 Shade 67 78 90 Shade 22 33 45 57 70 87 Shade E 16 9 2 6 17 38 90 24 14 5 5 16 31 55 90 23 12 0 12 25 42 64 90 SE s 61 54 47 Shade 39 84 28 73 7 52 45 0 69 59 50 Shade 40 85 29 74 14 59 10 35 45 0 68 57 45 90 33 78 20 3 19 45 ' 65 48 28 0 . sw Shade 45 Shade 80 45 Shade 71 45 r PM -* N NW W sw s SE By linear interpolation, the diffuse irradiation is id - 25 + (33 - 25) = 26.6 Btu per (hr) (sq ft). The total solar irradiation is I, - 152.0 + 26.6 - 178.6 Btu per (hr) (sq ft). PERIODIC HEAT FLOW THROUGH WALLS AND ROOFS The calculation of heat flow, through a structural section of a building exposed to the weather, requires consideration of the diurnal cycles of solar irradiation and air temperature. These cycles and other factors lead to a periodic variation in the instantaneous rate of heat flow into the weather sur face, and a related periodic variation in the rate of heat flow into the air-conditioned space. Because of heat capacity and other factors, these heat-flow cycles are, in general, out of time phase and unequal in amplitude. In order to calculate the rate of heat entry into the weather surface of a building, it is necessary to know: 1. The intensity of direct solar radiation striking the surface. 2. The absorptivity (or reflectivity) of the surface for direct solar radiation. -. 3. The intensity of diffuse or sky solar radiation striking the surface. . 4. The absorptivity (or reflectivity) of the surface for diffuse or sky solar radiation.* 5. The rate at which the surface emits radiation to the sky and other surroundings. 6. The rate at which the surface absorbs the low temperature radiation emitted by the sky and other surroundings by virtue of their temperatures and radiating characteristics. 7. The temperature of the surrounding air. 8. The temperature of the outer building surface. 9. The unit convective conductance for beat transfer be tween the air and the building surface. ' The Sol-Air Temperature The complex interrelationship of the above factors can be considerably simplified through the use of the sol-air tem perature concept. The sol-air temperature U is the tempera ture of the outdoor air, which, in the absence of all radiation exchanges, would give the same rate of heat entry into the surface as would exist with the actual combination of incident solar radiation, radiant energy exchange with the sky and Table 7 .... Approximate Solar Declinations in Degrees Dote Oedinotion Date Declination April 1 May 1 May 15 June 15 4.5 10.0 15.0 19.0 22.0 23.5 July l July 15 - Aug. 1 Aug. 15 Sept. 1 Sept. 15 23.0 21.6 18.0 14.0 8.5 3.0 -fCooling Load 179 Table 8........ Summer Design Sol-Air Temperatures Used for Tables 9 and 10 Sol-Air Temperature t. Fahrenheit Degrees Any Surface0 Horiz. North East . Sooth ` West Ratio*; 0 0.225 0 0.225 0.125 0.225 0.125 0.225 0.125 1 AM 2 3 4 6 7 8 9 10 11 1 PM 2 3 4 5 6 7 8 9 10 11 24 Hr Avg. t* 77 76 76 75 74 74 74 75 77 80 83 87 90 93 94 95 94 93 91 87 85 83 81 79 ' 83.1 77 76 76 75 74 74 76 91 106 119 129 137 142 144 140 132 120 107 96 90 85 83 81 79 100.5 77 76 76 75 74 74 74 75 77 80 83 87 <90 93 94 95 94 93 .91 87 85 83 81 79 83.1 77 76 76 75 74 75 110 123 126 125 117 108 92 93 95 95 94 93 91 87 85 83 81 79 93.0 . 77 76 76 75 74 80 93 100 103 104 100 96 92 93 - 94 95 . 94 93 91 87 85 83 81 79 88.4 77 76 76 75 74 74 74 75 82 93 102 110 114 115 111 104 99 95 91 88 85 83 81 79 89.0 77 76 76 75 74 74 74 75 78 86 93 99 104 105 104 100 96 94 91 87 85 83 81 79 86.2 77 76 76 75 74 74 74 75 77 80 83 89 96 110 124 135 141 139 125 103 85 83 81 . 79 . 93.0 77 76 76 75 74 74 74 75 77 80 83 87 92 102 111 119 120 118 111 94 85 83 81 79 88.4 a -- aarf&ce fcwptiviiy, rod -- 0.0; dark wells -- 0.0, and li*ht walla -- 0.6. fm -- unit convective conductance m 4.0 Btu per (hr) (F deg). b Value* in this oolumo are magnitude* oi , the outdoorair temperature. other outdoor surroundings, and convective heat exchange with the outdoor air. . The sol-air temperature data** *19 as developed by Mackey and Wright for an industrial atmosphere were used as a basis for preparing Table 8 showing summer design sol-air tem peratures. Sol-air temperatures may also be estimated from experimental observation of surface temperatures of walls and roofs which appear in the literature.11' u Both analytical and experimental studies have been made on the problem10 of heat flow through walls and roofs. Those concerned with a further study of the details of cooling load estimates in particular relation to periodic heat' flow will find much of value and interest in the reports of experimental studies of these problems.11 " " "10 The reader may also refer to the Cooling Load chapter of The Guide 1952 for the theory of heat flow through walls and roofs. PRACTICAL TABLES FOR CALCULATING SOLAR HEAT GAIN THROUGH WALLS AND ROOFS The analytical10 method reported by Mackey and Wright was used by Stewart1* to obtain temperature differentials based on Table 8 and shown in Tables 9 and 10. These ana lytical procedures, as well as those using Tables 9 and 10, presented here, yield generally higher rates of heat gain than reported for-Pittsburgh in early ASHAE experimental studies. Current authoritative opinion indicates a preference for analytical calculations. Thermal and physical properties of materials used in these tables are given in a paper.10 The rate of heat flow is obtained by multiplying the overall heat transmission coefficient of the structure by the equivalent temperature differential obtained from the tables. .* Tables 9 and 10 were developed by using an outside surface conductance of 4.0 and an intide film conductance of 1.65 Btu (hr) (sq ft) (F deg). A- reduction was made in the tem perature differentials for roofs amounting to some 20 percent of solar radiation as explained by Stewart.10 This was to compensate for several factors, one of which is the radiant heat lost to the sky which is not included m the Mackey and Wright method. Experimental work by Parmelee17 and pre vious work by Brunt10 give data showing the magnitude of thU radiant heat loss from a roof or wall to the sky. Temper ature differentials for roofs probably would be reduced below those shown in Table 9 whenever the radiant heat lost to the sky is included in calculation of sol-air temperature. The temperature differentials for roofs were based on an in side surface conductance of 1.65 because the charts prepared by Mackey *nrl Wright10 used this value, and it was not practicable to .repeat their work using a different film co efficient. An examination of the values given in their paper indicates that the temperature differential would be changed very little even if a value 1.20 were used instead of 1.65. To obtain the heat-flow rates through roofs, more accurate 180 CHAPTER 13 Table 9..Total Equivalent Temperature Differential for Calculating Heat Gain Through Sunlit and Shaded Roofs Sim Tine Description of Roof Cwulnntion* 1959 Guide 1' Wood* or 1' Wood* + 1* or V insulation Upfcf Comfrecffoa Roof*--Exposed to Sen 12 38 54 62 50 26 10 4 0 Medium Construction Roofo--fxpoted to Sen 6' Concrete 6' Concrete + 2* insulation 4 6 24 ' 38 46 44 32 IS 12 6 6 20 34 42 44 34 20 14 Roots Covered <riffi Water--Exposed to Son Light construction roof with 1' water Heavy construction roof with 1' water Any roof with 6* water 0 4 16 22 18 14 10 2 -2 -2 -4 10 14 16 14 10 -2 0 0 6 10 10 8 4 0 6 0 Light construction Heavy construction Roots with Root Spro/i Exposed to Sen '0 4 * 12 18 16 14 10 2 0 .. -2 . -2 2 8 12 14 12 10 6 Roofs in Shade Light construction Medium construction Heavy construction - -4 0 -4 -2 -2 -2 6 12 14 12 8 2 2 ` 8 12 12 . 10 6 04 8 10 10 8 * Includes H in. felt roofing with or without dec. U>7 also be used for h'npt roof, t Nominal *^'~l-- ~ n of ^ wood. 0 2 4 .. Notes for Table 9 ITohl beet *y|lilir--from solar) f g__r__J radiation end tempntore difference l _ J Equivalent temperatute * l between mtdnn end man air. Rtn ' ' .... - v J axrffioont for sum- V x \ mer Btu per (hr) ( l(eq ft) (F dec) J 1. Boaree. Calculated by Mackey and Wright mathod (see reference lift) and adjusted after studying A8HAE original test data. Estimated (or about August 1 in 40 deg north latitude. (For sol-air temperatures osed in calculations see Table A) For typical design day where the maximum outdoor temperature is 95 P and tninimtim temperature at night it approximately 75 F (daily rangeof temperature, SO F) menn24 hr temperature 84 Ffma room temperature of 80 F. All roofs have been assumed a dark color which absorbs 60 percent of solar radiation, and reflects only 10 percent. 6. Application. These values may be used for aQ Dermal air conditioning estimates; usually without correction, in latitude 0 deg to.SO deg north or south when the load is calculated for the hottest weather. Note 5 explains haw to adjust the temperature differential for other room and outdoor temperatures. . A Roof*. If the roof is peaked and the heat gain is primarily due to solar radiation, use for the area orf the roof, the area projected on a horizontal plane. 4. Attica U the ceiling is insulated and if a fan b used in the attic for positive ventilation, the total temperature differential for a roof exposed to the sun may be 5. Corrective*. Forteaspmtiura HJfemc* tsulm outdoor maximum design temperature minusroost it iifcrtntfrra tSdog. If theoutdoor design temperature minus room temperatureb differentfrom thebase of 15 deg, correctas fettowa: When thedifference b greater (wlm) tt. tf deg add the excess to (or subtract the deficiency from) the above differentials. . For outdoor dotty range of Uapmtvro attar C6m tO dog. If the daily range of temperature b leas than SO deg. add 1 deg for every S deg lower daily range; if the daily range b greater than SO deg, subtract 1 deg forevery S deg higher daily range. For example, the dgSy range in tf Florida b 13 deg or 8 deg leas than 10 deg. there fore, the correction b +4 deg at all boura of the day. ' . Cooling Load 181 Notes for Table 9.... Total Equivalent Temperature Differentials for Calculating Heat Gain Through Sunlit and Shaded Roofs (Concluded) . Lifkt Color*. Creditshould not be taken for light oolored roofsexcept where the permanence of the light color b established by experience, as in rand areas or where tbera b tittle smoke. When the exterior surface of roof aspoaed to the sun b a light color, such as white or aluminum (which absorb approximately 50 percent sod re flect 50 percent of the solar radiation) add to the tempereture differential for roof in shade 55 percent of the difference between the roct in sun sad roof in shade. When the roof exposed to the sun b e medium color such as light grey, blue or green, or bright red, edd 80 percent of this difference. for tolar tronsmsstiva ta latitvdri etkor ikon tfi dot avrtl, o*d ia otter vtontkt. The table values of temperature differential) will be approximately correct far a roof ft) ts, following months: Nom Lawtodb Soars Law-run* Latitude (dec) Months latitude (dec) Monthe 0 AQ months 10 AH IWrtlltlw 0 All months 10 All months AQ mouths except Nor, Dee, Jan 80 All mouth* except May, June, July 80 Mer. Apr, May, June. July, Anf, Sept so Sept, Oct, Nov, Dee, Jan, Feb, Mer 40 April, May. Jane, July, Auc 50 May, Jane, July 40 Oct, Nov, Dee, Jan, Feb 60 ' Nov, Dec, Job For other months, the total temperature differential (lx) may be approximated by the use erf the following formula: . ( -- temperature differential for the same roof in shade for desired time erf day; obtained from Table 6. /, m mtiiipum solar transmission through fbse, Btu per (hr) (*q ft) for flat skylight in Aug., 40 deg north latitude (Nate; this b maximum value irrespective of time). /, m same as / except use the maximum value for flat skylight, (or month, and latitude desired for tx - t -- temperature differentialfor particular roof expoaed to sun lor the desired time of day burn Table A (Note that t5ts vtaist adjvotvtnU only for tolar radiation and that lion meg h additional correctivefor outdoor temperature.) . . values will be obtained if the overall heat transmission co efficient is calculated using 1.2 as the inside film conductance for summer. The roof coefficients of transmission for summer shown in Table 11 are based on surface conductances /* of 4.0 for an outside roof surface and 1.20 for an inside ceiling surface. The outside conductance 4.0 is used for summer because, it " corresponds to a wind velocity of approximately 7.5 mph averaged for rough and smooth surfaces, and is more repre sentative of summer wind velocities. Also, the lower wind velocity should be used in order to be on the safe side in' determining .the sol-air temperature. The inside conductance - 1.20 is used because the convective portion of the film con ductance for downward heat flow from a horizontal surface " is appreciably less than the winter conductance for heat - flowing upward. ' Since there is little difference in tvail transmission coefficients for summer, based on the conductances of 4.0 and 1.65, and - the winter coefficients, based on 6.0 and 1.65, it is recom mended that the overall coefficient U, for walls, be taken directly.from the tables in Chapter 6 in which they are based on an outside film conductance of 6.0, corresponding to a 15 mph wind velocity. . Advantages of Equivalent Temperature Differen tial Method ` The advantages of the equivalent temperature differential method of determining the total heat transmission are given in following paragraphs, and are apparent from Examples 6 to 7. 1. The total sensible heat flow is obtained by multiplying the overall heat transmission coefficient U, and the equivalent temperature differential indicated in Tables 9 and 10. 2. The temperature differentials listed for a few representa tive types of construction may be used on all classes of walls and roofs, even though the overall heat transmission coefficient is different, provided the structure has thermal and physical properties similar to one of those listed in Tables 9 ana 10. 3. Adjustments can be made, according to instructions given in the footnotes, for room and outdoor conditions differ ent from those on which the tables are based. Examples of Use of Equivalent Temperature Tables Example 8: Given: A roof is constructed of 6 in. of stone concrete with 2 in. of insulating board and tar felt roofing % in. thick, and is exposed to the sun. The location is the central part of the United States. Find the rate of heat flow into building at 2:00 p.m. during July for an outdoor design temperature 95 F, and an indoor temperature 80 F. Solution: From Table 9 in 2 pjn. column for64n. concrete plus 2-in. insulation find the total equivalent temperature differential 34 deg. The overall heat transmission coefficient for summer is taken from Table 11 and is found to be 0.13. The beat-flow rate equals 34 X 0.13 -- 4.42 Btu per (hr) (sq ft). Example 8: For the conditions of Example 8, End the rate of heat flow into building at 2:00 p.m. during July for design temperatures of 105F (outdoor) and 78 F (indoor).'Daily range of temperature 30 deg, i.e., outdoor temperature minimum of 75 F which occurs at 4:00 or 5:00 a.m.; this being 30 deg less than the maximum. Solution: Malm correction in equivalent temperature differ ential in accordance with Note 5 in Table 9 as follows: ' The correction for 27-deg design temperature difference is * (27 - 15) - +12. The correction for 30-deg daily range is ^ ^ = --5: Net total correction is +12 -- 5 = +7. The heat-flow rate at 2:00 p.m. is (34 + 7) X 0.13 8 5.32 Btu per (hr) (sq ft). A method of determining heat-flow rates, when structure is not given in Tables 9 or 10, is illustrated in Example 7. Example 7: A 4-in. stone concrete roof covered with an average depth of 4 in. of cinder concrete (k 4.9), on which is placed a %-in- thick felt roof with 3+in. pitch and slag 184 CHAPTER 13 1959 Guide Table 11.... Summer Coefficients of Heat Transmission U of Flat Roofs Covered with BuilMJp Roofing* Bit* par iftoori fafuore Pool) IP deg difference between (he air on the two (Mod Insulation on Top of Deck (Covered With Butff Up Roofing) Tjrpe of Roof Deck (Ceflfog not shown) Flat metal roof deck --v Thickness of Roof Peek (inched No Celling-- Undertide of Roof Exposed Furred Celling with Air Space, Metal lath and Platter bmdoting board4 thickness, in. No No tnsutaHng board4 thickness, in. insulation 1 2 bredatice H 1 2 4 Ply Felt Roof Ditto + M in. Slag 4 Ply Felt Roof m 0.73 0.35 0.23 0.17 0.13 0.40 0.25 0.18 0.14 0.12 0.54 0.30 0.20 0.16 0.13 0.34 0.22 0.16 0.13 O.U 0.67 0.33 0.22 0.17 0.13 0.38 0.24 0.18 0.14 0.12 -- 1I Gypsum and wood fiberb , ------^ Ditto +Hin. Slag m 4 Ply . Felt Roof 2 4 6 Ditto 2 4 + H in. Slag 6 4 Ply Felt Roof 2H 3M Ditto 2* + M in. Slag 3H 0.50 0.65 0.59 0.54 0.49 0.46 0.42 0.28 0.20 0.15 0.12 0.33 0.22 0.16 0.13 0.31 0.21 0.16 0.13 0.30 0.20 0.16 0.13 0.28 0.20 0.15 0.12 0.27 0.19 0.15 0.12 0.28 0.19 0.14 0.12 0.32 0.37 0.36 0.33 0.31 0.30 0.29 0.21 0.17 0.13 0.11 0.24 0.18 0.14 0.12 0 23 0.17 0.13 0.12 0.22 0.17 0.13 0.11 0.21 0.16 0.13 0.11 0.21 0.16 0.13 0.11 0.20 0.16 0.13 0.10 0.34 0.28 0.29 0.25 0.23 0.17 0.13 0.12 0.20 0.15 0.12 0.11 0.20 0.16 0.13 0.11 0.18. 0.14 0.12 0.10 0.25 0.21 0.22 0.19 0.18 0.14 0.12 0.097 0.16 0.13 0.11 0.094 0.16 0.13 0.11 0.093 0.15 0.13 0.10 0.090 Wood8 -- feec-L-j-S V- / """ ' 4 Ply Felt Roof l iH 2 3 1 Ditto lH + H in. Slag 2 3 0:43 0.33 0.29 0-22 ' n 9R n vd 0.20 0.10 0.19 0.17 0.16 0.13 0.15 0.13 0.13 0.11 0.12 0.11 0.11 0.09 0.35 0.29 0.26 0.20 0.23 0.20 0.19 0.15 0.17, 0.14 0.15 0.12 0.14 0.12 0.12 0.10 0.11 0.10 0.10 0.09 0.29 0.24 0.22 0.17 0.25 0.21 0.20 0.16 0.20 0.18 0.16 0.13 0.15 0.14 0.13 0.12 0.13 0.12 0.11 0.10 0.11 0.097- 0.094 0.085 0.18 0.17 0.15 0.13 0.14 0.13 0.13 0.11 0.12 0.11 0.10 0.09 0.10 0.093 0.090 0.081 * Tbe summer coefficient* ere considered temporary, end have been retaliated with *a outdoor wind velocity of 8 mph. For rammer en tneids eurfeee conducteoce of t.I be* been osed instead of tbe resuier 1.8$ value. In eQ of three roolt e 4 ply felt roof has bees awumed H in. shlf.k, thermal conductivity -- 1.33. Pitch and alac hon MfiiflMti -- xinitiorml thiflkre-- of U in. whieh has hem Mg|nm1 thermal crmHnrtigity m I.Q. In both coses thermal eondnetivity refer* to one tack thick- b 87)4 percent fyr--13)4 percent wood fiber. Thickness indicated isdudea H in. fypaum board. This ia a poured roof. * Nominal thickness of wood b apreifiad, but aetnal thickness wsa used in --i-"i-*i~t 4 If eorkbcerd insulation is used, thecoefficient U may be decreased 10 percent. surface, is exposed to the sun. The location is the central part of the United States. Design temperatures are: outdoor 95 F; daily range 20 deg; indoor temperature 80 F. Find the heatflow rate at 2:00 p.m. for a day w July. Solution.' For the purpose of selecting the equivalent tempera ture differential, this construction is assumed to be equal approximately to an uninsulated 6-in. concrete roof, for which the equivalent temperature is found to be 38 deg in the 2:00 pan. column of Table 9. Calculate the overall heat transmission coefficient U (see Equation 3 of Chapter 9) of the roof as follows: . U - --------------------------------------- :-------------- - - 0.33 14 4 0,375 Q.SO 1 1.2 + 12 + 4.9 + 1.33 + 1.00 + 4.0 The heat-flow rate is then 38 X 0.33 equals 12.5 Btu per (hr) (sq ft). TABLES FOR CALCULATING SOLAR HEAT GAIN THROUGH GLASS AREAS Basic Principles In order to set forth the principles involved in calculating heat flow through glass areas, the general instantaneous heat balance relation will be presented. It will be shown sche matically in Tig. 2. The net heat gain for the indoor space is the result of several contributing factors. - * The following observations concerning the behavior of Cooling Load glass with respect to radiant energy will lead to a better understanding of the heat balance relation. 1. Glass transmits, in varying degrees, radiation having wavelengths between 0.29 and 4.75 microns. The percentage . of each wavelength transmitted is dependent upon the chem ical and physical characteristics of the glass, and upon the angle of incidence of the radiant energy. Of the energy not transmitted, part is absorbed and part reflected. 2. Glass is opaque to radiant energy emitted from sources below 450 F. . 3. Because of the above principles, it is convenient to group radiant energy into two classifications, solar radiant energy and low temperature radiant energy. The complete heat balance for a glass section can be ex pressed for a unit time interval as follows: Fig. 2.,..Instantaneous Heat Balance for a Glass or Glass Block Section Eotal heat flow, ~| trough glass sectionJ [Transmitted, "j solar radiationJ Heat flow by convective"! [and radiative exchanges at I the indoor surface J (Za) The second term of the right, side of Equation 2a can also be expressed by a heat balance equation as follows: Heat flow by convective-! ["Absorbed-] [and radiative exchanges I = I solar | at the indoor surface J Lradiation J PRadiative exchanges be ~] | -tween outer surface of glass | Land outdoor surroundings J (2b) [Convective exchanges "]- [~Heat storage-] between outer surface of j I within the I glass and outdoor air J [_glass sectionj Equations 2a and 2b can be combined and expressed in symbolic terms by Equation 2c. Tabular values of the two bracketed terms of Equation 2a are presented later in this section for various types of glass for specific design conditions. (?/A) = + TifjJ + [<h>1d + a*fj + efR -- ,*R,, where t.) - 51 (2c) is/A) " instantaneous rate of heat flow, Btu per (hour) (square foot). to , Trf = transmittance of glass for direct and diffuse solar radiation, respectively. 185 Id , It *= incident direct and diffuse solar radiation, respec tively, Btu ner (hour) (square foot). Oi<s absorptance of glass for direct and diffuse solar radiation, respectively. , emissivity of glass at temperature t,, . ft, *= low temperature radiant 'energy falling on glass from outdoor surroundings, Btu per (hour) (square foot). R,t * low temperature radiant energy emitted by a sur face with emissivity equal to 1.0 at temperature t,, /, =* outdoor. convective conductance, Btu per (hour) (square foot) (Fahrenheit degree). tt, * temperature of outdoor surface of glass, Fahrenheit. t, = temperature of outdoor air, Fahrenheit. S * rate at which glass stores energy, Btu per (hour) (square foot). Transmissivity and absorptivity vary with both wave length of the incident radiation and incident angle. Normal incidence transmittance values for some commonly used types and combination are given in Table 14.. Some varia tion in these values can be expected in practice due to vari ations in ' manufacture and in solar energy distribution. However, a change in transmissivity causes a compensating change in absorptivity. Generally, the total heat flow is not greatly altered. Transmittance data for a number of types of glass and various patterns of 8>in. glass block are given in ASHAE research papers.1*1 " " " **>u As stated earlier in this chapter, present data as to the value of R, are inadequate, so for the present it is suggested that fc be increased to include radiation, and the term tfji, -- (gJtf be disregarded. It is not practicable to give values of S in this chapter. However, for ordinary glass, the value of 5 is amaH. Fig. 3 is a graphical solution, for single gloss, of Equation 2b. Only absorbed solar radiation is considered, although low temperature radiation exchange and heat storage can be added algebraically to atIt if such data are available. The small thermal resistance of the glass has been neglected. The heat-flow rates are for 80 F indoor temperature, an in- Fig. 3 .... Convection and Radiation Heat How for Vertical Single Glass 186 CHAPTER 13 1959 Guide Table 12 30 Deg north 40 Deg north , 50 Deg north * Itelien indkfttfl Instantaneous Rates of Heat Gain Due to Transmitted Direct and Diffuse or Sky Solar Radiation by o Single Sheet of Unshaded Common Window Glass For Qnr Afaiosphoros and 18 Oeg Dedteotion, North (Aogoxf I) Note; For tote} testontoaeov* boat goin, add Hwn raiuei to the Table 13 value* fottontaneotn Hoot Gain In Bte per (hr) Uq ft) AM - 1 6 a.m. 7 8 9 6 p.m. 5 4 3 10 2 11 1 12 . 5 a.m. 6 7 8 7 p.m. 6 5 4 93 10 2 11 1 12 5 a.m. 6 7 8 7 p-m. 6 5 4 93 10 2 11 1 12 N 25 23 16 16- 17 18 18 3 28 16 U IS 16 17 - 17 20 25 18 18 14 IS 16 16 NS SE 98 108 52 155 190 110 148 205 136 106 180 136 54 128 116 20 59 78 19 19 35 7 62 116 131 67 149 195 . 124 129 205 156 79 180 162 31 127 148 18 58 113 17 19 64 54 54 20 128 149 81 139 197 136 107 202 171 54 176 183 18 124 174 16 57 143 16 18 96 S SW s5 10 10 14 18 21 IS 34 17 45 19 49 35 00 76 11 10 18 It 42 14 69 16 90 23 98 64 38 87 It 10 32 It 72 14 110 16 136 42 144 96 W NW Horiz. 6 10 18 . IS 5 10 18 IS 16 16 18 18 19 19 00 66 10 10 It 12 14 14 16 16 17 17 19 17 88 77 10 . 10 It It U 14 IS IS 16 16 18 16 17 71 137 195 241 267 276 1 25 77 137 ` 188 229 252 259 6 34 80 129 173 206 227 234 T PM - EN NW W $w S SE KE Horiz. sr_ 5 a.m. 6 7' 8 9 10 11 12 2 3 4 5 6 7 8 9. Table 13.... Instantaneous Rates of Heat Qain by Convection and Radiation from a Single Sheet of Unshaded Common Window Glass . For Clear Afmatpfaere* and 18 Dog Pedioaften, North (August f) For 30, 40, 50 Dog North latitude For 80 F Indoor Temperature Note: For total instantaneous heat gate, add these value* to 8m table 12 values lititantoneou* Hoof Gain in Bfu per (far) (*q FT) Oty-Butb F Dog N NE E SE S SW w 74 74 75 77 80 83 87 90 93 94 95 ' 94 93 91 87 85 83 -6 -6 -6 -6 -6 -6 -6 -5 -4 -4 -5 -5 -6 -6 -5 -2 -2 -3 -5 -5 -5 -3 0 1 0 -2 -3 -3 ' 0 243 1 00 3 '4 6 6 5 3 3 8 8 10 11 10 9 8 12 12 12 13 14 13 12 15 15 15 16 17 17 17 16 16 16 16 18 19 19 17 17 17 17 19 21 21 16 16 16 16 17 20 20 15 15 15 15 15 18 19 13 13 13 13 13 14 15 8 8 8 8 8 8 8 6 66 6666 .3 3 3 3 3 3 3 - NW . -6 -6 -5 -3 0 3 8 12 15 17 19 19 18 15 8 6 3 Horiz. -6 -5 -3 0 .3 8 13 16 20 21 21 19 17 13 8 6 3 IteKtsr Cooling Load 187 Table 14 ... Application Factors to'Apply to Tables 12,13 and 15 to Obtain Instantaneous Rates of Heat Gam for Various Types of Single Flat.Glass-and Combinations of Two Sheets of Hat Glass Spaced at. ^ In. Glass* . . Normal Incidence Tmnxmilfonce Factor to Apply to Fafale 12 Factor to Apply to Table 13 Single common window Single regular plate Single heat absorbing plate Double common window Double regular plate Heat absorbing plate outdoors) Regular plate indoors j 0:87 0.77. 0.41 0.76 . 0.60 0.35 1.00 0.87 0.46b 0.85 0.66b 0.37b 1.0m* + 0.0(F)4 l.OUQ + 0.25(F) 1.0(A) + 1.00(F) 0.6(A) + 0.10(F) 0.6(A) + 0.55(F) 0.6(A) + 0.75(F) . * Common window (less H in- thick. Piste (less H in- thick. b Far better precision, increase factors 10 percent when dm is in the *<* * X values ere Table 13 values. d y valttee are Table IS values. ' side surface conductance for convection fa as given by Equa tion 3, and an equivalent surface conductance for radiation Sn as given by Equation 4. Inside surfaces seen by the glass are assumed to radiate as a black body at room air tempera ture. Sn - 0.27 ((,,- - " (3) where ' Iti " temperature of inside surface of glass, Fahrenheit. . t{ = temperature of indoor air, Fahrenheit. A more complete treatment of the problem is given in an ASHAE research paper.11 Design Tables for Fiat Glass . Tables 12 and 13 give design values of instantaneous rates of heat gain for tingle unshaded common window glass for a solar declination of 18 deg. This corresponds to a nominal August 1 day. The tables are based upon the solar intensity values for a clear atmosphere as given in Table 4. Tal le 12 values represent the first bracketed term of Equation 2a; therefore, the values are dependent only upon values of I and r. Table 13 values represent the second term of - Equation 2a, and are based upon a 80 F indoor temperature and a dry-bulb temperature cycle, with a 95 F maviimim as tabu lated. The total heat gain is the sum of the Table 12 and Table 13 .values. In preparing Table 13, convection and' radiation heat exchange were.combined, and a'combined surface con ductance`of 4.0 used. Corrections to be applied for other design temperatures are givenin Table 24 in a later section Effect of.Deviation from Design Conditions. ' ' Tables 12 and 13 may be used for other types'of glass with good accuracy, by using the factors given in.Table' 141 Table 12 values are multiplied by the appropriate' factor given in Table 14 to obtain heat gain due to transmitted solar radia tion. For glasses having a transmittance for normally in cident radiation differing from the table values, factors may be found by linear interpolation. To obtain instantaneous rates of heat gain by convection and radiation, two steps are required. First, Table 13 values are multiplied by the ap propriate coefficient of X listed in Table 14: Second, Table 15 values are multiplied by the appropriate coefficient of Y listed in Table 14, and added to the first value. All convection and radiation gain values for double glass were computed for a >4-in. air space. No great error is involved in cooling load estimates if these are used for double glass with other air spaces. Example 8: Find the total iostantancous heat gain through a single sheet of regular plate glass in a southwest wall at 2 p.m. sun time and 40-deg north latitude on August 1. The maximum dry-bulb temperature for design'is 98 F; the atmos phere is clear. The indoor temperature is 80 F. Soluiton; From Table 12 the heat gain due to transmitted radiation ts 148 Btu per (hr) (sq ft) for common window glass; . from Table 14, the factor for regular plate glass is 0.87. The coefficient of X in Table 14 is 1.0, while X is found from Table 13 for common window glass for the same hour, orientation and latitude. The coefficient of Y in Table 14 is 0.25, while the Y value is found from Table 15 for a southwest wall at 2:00 p.m. and 40-deg north latitude. The correction for design dry-bulb temperature is found from Table 24 to be 1.0 Btu per (hr) (sq ft) per degree difference from 95 F design temper ature. The total instantaneous beat gain is, from Equation 2a, q - 0.87 X 148 + 1.0 X 19 + 0.25 X 27 + 1.0 (98 - 95) -- 157A Btu per (hr) (sq ft). Design Tables for Rolled Figured Glass Tables 16 and 17 give-design values of instantaneous rates of heat gain for a number of common patterns of single ver tical sheets of rolled figured glass. The tables are for a solar declination of 18 deg, which corresponds to a nominal August 1 day, and are based upon the solar intensity values for a clear atmosphere as given in Table 4. The values are given in terms of corrections to apply to Tables 12 and 13. The heat gain due to transmitted solar radiation is found by multiplying the Table 12 values' by the approximate per centages given in Table 17. To obtain instantaneous rates' of heat gain by convection and radiation. Table 15 values' are multiplied by. the appropriate value of Y from Table 16 and then added to the corresponding Table 13 values.- The total instantaneous heat gain is the sum of the gain due to transmitted solar radiation and the gain by convection and radiation. ' The values given in Tables 16 and 17 are based upon-an ASHAE research paper11 to which the reader is directed for additional data. The values in Tables 16 and 17 may be used with fair precision for other patterns of similar transmittance and surface characteristics. For example, the data for ham-' roered glass may be used for glass having shallow, closely spaced ribs or for glass having small, closely spaced circular indentations. Because some patterns have distinct orients- 188 CHAPTER 13 1959 Guide Table 15.... Heat Absorbed in'Glass. Values of Y to be Used with Factors, m Table 14'and Table 16 in the. - Determination of Instantaneous Rates of Heat Gain Due to Convection and Radiation for Various Types of Single Giass ana' Combinations of Two Sheets of Giass Spaced at in. . - . far Cfear Atmoiphmm and Ifl Dtg Decfinatioa, Nwtt [Aiignt I) - Sun Tam latitude Vatoe* of Y Btu per (hr) (sq ft, N Nf E SC s SW W NW Horiz. 5 a.m. 0: 7 8 9 10 11 12 1 p.m. 2 3 4 6 6 7 Son Time . 40 Degrees North latitude' . 0 4 2 2 2 3 3 3 3 .3 3 3 2 4 0 SC 0 16 24 22 16 5 3 3 3 3 3 3 2 1 0 s 1 0. 0 18 9 1 30 20 2 33 25 2 30 29 8 0 1 2 2 3 25 27 14 3 12 21 18 3 3 15 19 12 3 3 19 22 3 3 16 27 3 3 10 30 3 3 4 29 2 2 2 23 1 1 1 14 00 0 2 SW Sun Time latitude 00 11 22 22 33 33 33 33 10 3 24 4 31 * 15 36 23 34 27 24 21 33 SE S 0 3 11 21 32 37 42 45 44 41 35 26 17 6 1 SW 5 a.m. 6 7 8. 9 0 7 IS 22 24 10 . . 11 . 12 1 p.m. ' 30* Degrees North 22 16 6 3 3 3 -4 5 6 7. - 3 3 2 1 0 * Values of Y for 8 and 9 p.m. ere sero. * For N, NE, E, W, HW, and borisoBtal usetOdeg North Latitude values. 0 1 2 2 3 5 7 9 9 6 5 3 2 1 0 0 5 a.m. 16 27 28 39 3 10 3 11 50* 4 12 Degrees 14 1 p.m. North 21 2 27 3 26 4 21 5 11 6. 07 2 13 22 28 30 31 27 20 9 3- 3. 2 2 1 0 0 1 2 3 13 20 25 27 25 22 16 7 2 1 0 0 1 2 2 3 3 5 17 26 32 33 31 26 17 7 tion properties, no attempt has been made to give values for nonvertical glass. .- . Design Tables for Glass Block Walls . Table 18 describes the. glass block patterns discussed in fonowing text. Table 19 gives design values for instantaneous heat g*.in due to transmitted direct and diffuse solar radiation for 8-in. hollow glass block of Type I pattern. For glass blocks of Types IT to V the corresponding instantaneous heat gain is found by multiplying the value found for Type I block from Table 19 by the appropriate factor from Table 20. The instantaneous rate of heat gain due to convection and radiation for unshaded-.8-in., hollow glass blocks of- Types 1 to, V are given in Table 21. The convection and radiation gain values for all blocks are so nearly the same that a single table suffices. Note, however, that corrections must be made for certain hours for east, and west facing walls of some patterns. - . ' Tables 22 and 23 give instantaneous heat gain values for two types of glass block design for use in skylights. The Type VI block is 10^ x 10^ in. and the Type VII block 12x12 in. - It should be noted that the data for Type VI glass block in Tables 22 and 23 are for panels as assembled. Since the manner of mounting this type of block is standard the ratio of glft-g* area to opaque area is virtually constant from one skylight to another. The Type VII glass block .may be mounted on a wide range of center-to-center distances. The. opaque portion of the assembly should be given separate consideration independent of the glass block. See Reference 24 for more complete information. ' These tables are based upon the solar intensity values for a clear atmosphere as given in Table >4. For solar energy transmittance data refer to References 21 and 24. The values of convection and radiation gain are based on values of 80 F for indoor air temperature, a maximum outdoor air temperature of 95 F and upon experimentally determined values of solar energy and temperature difference between the two.faces. Indoor and outdoor convection and radiation heat-transfer values are the same as those used for common Cooling Load 189 Table 16 .... Application Factors to Apply to Tables 13 and 15 to Obtain Instantaneous . Rates of Heat Gain for Vertical Single Sheets of Rolled Figured Glass Having Normal Incidence Transmittances and Listed Thicknesses (Smooth Side Indoor, Figured Side Outdoor) (5m Table 17 hr factor* to Apply to Table 12 Vetoes) - Glass Pattern Normal hadeace Ttnnmifflmne Thidtness, Inches factor to Apply to Table 13 Hammered Hammered, etched both sides Deep ribs on X i- centers Hammered heat absorbing Hammered heat absorbing, etched both sides * X values ere Table IS valoee. b T nloee are Table IS valuea. U*e 0.4000 lor east and west (leas. 0.75 0.67 0.77 approx. 0.21 0.14 X X * Use 0.60(7) far out and west dam. Dae OlSWV) tor east and west r1--- * Uee 0.99(7) for south glass. l.OGD* + 0.50(F)*- 1.0(X) + 0.65(F)4 1.0(X) + 0.50(F)* 1.0(JT) + 1.15(F)' 1.0(Z) + 1.40(F) Table 17 .... Instantaneous Rates of Heat Gain Due to Transmitted Direct and Diffuse Solar Radiation by Unshaded Rolled Figured Glass . Multiply to Table 12 Values by These Percentage factor* far dear Atmospheres and 18 Degree* DedmaSoa, North (August 1) far 80, 40, and SO Degrwe* North latitude Note: To obtain total instantaneous heat gain odd adjusted Table T2 value* to odjvsted Table 13 vatoe* Instantaneous Meet Gain Due to Transmitted Solar Radiation as a Percentage of Single Sheet of Common Window doss Sen Time AM--* i 5 ajn. .7 p.m. 66 75 8- 4 93 10 2 11 1 12 N, NW W, SW 80 80 80 80 80 80 80 80 ' Hammered NE SE 80 85 70 85 85 75 80- 85 80 75 85 80 60. 80 80 65 75 75 80 60 70 80 80 -- 60 Hammered and Etched s N, NW NE W, SW SE so 60 80 60 80 60 75 60 60 60 65 60 65 60 65* 60 65 75 55 65 75 50 60 70 55 55 65 55 50 55 55 55 50 55 60 50 50 60 60 50 S 60 60 60 60 50 50 50 50 Son Time 5 a.m. 6 7 8 9 10 11 12 7 p.m. 6 5 4 3. 2 1 T PM--* gibs aa fas. Centers Hammered Heat Absorbing 60 60 60 . 60 60 60 ^ 60 ' 60 75 85 25 60 80 85 30 60 65 85 40 60 40 80 50 55 30 70 65 35 40 40 65 35 60 35 40 35* 60 60 35 45* 25 25 25 . 25 25 25 25 25 20 20 20 20 20 20 25 25 25 25 25 20 20 .20 20 25 20 25 20 25 20 25 20 25 20 20 20 20 20 20 20 20 N, NE 6.SE NW W SW $ N, NE E, SE . NW- W SW S Sun Time f AM-* l . 5 ajn. 7 p.m. 66 75 -8 4 93 10 2 11 1 12 T PM --* Hammered and Etched Heat Absorbing N, NW W, SW NE E SE S 20 15 15 10 20 20 15 15 10 20 20 ' 10 15 10 20 20 10 15 10 20 20 10 10 10 10 20 15 10 10 10 20 20 10 10 10 20 20 20 10 10 N, NE S, SE NW W . sw S * Decrease value* 10 percent for SO dec latitude: inmease 16 percent far 60 deg latitude. * Increase value* 10 percent for 60 deg latitude. 190 CHAPTER 13 1959 Guide Table 18 .... Description of Glass Block Patterns Type I --Smooth Face A, D: Smooth B: Wide vertical ribs or flutes C: Wide horizontal ribs or flutes E: None ' Type II --Semi-Light Diffusing ' A, D: Narrow vertical ribs or flutes B, C: Etched or stippled E: None . Type III--Light Diffusing A, D: Narrow vertical ribs or flutes B, C: Etched or stippled E: Glass fiber screen " ' Type IV --Light Diffusing A, D: Close pitch deep horizontal corrugations B, C: Vertical light diffusing prisms E: None Type IVA--Light Diffusing .. Same as IV except corrugations vertical Type V --Light Directing A, D: Close pitch deep vertical corrugations B, C: Horizontal light directing prisms E: None ' Hollow dot* Block Utodfor Horizontal SkyUghh Type VI --Light Directing (skylight) A: Smooth surface B: Light-directing prisms C, D: Light-diffusing surface E: Clear glass fiber screen . Type VII--light-diffusing (skylight) A: Smooth surface . B, C: Stippled surface D: Narrow-ribbed surface E: Green-tinted glass fiber screen window glass. Table 24 gives corrections to be applied for other design temperatures. Example 9: Find the total instantaneous heat gain through an east wall of 8-in. hollow glass block of Type V pattern at 8 a.ra. and 50-deg north latitude. The design temperatures are 80 F indoors and 95 F maximum outdoor dry-bulb, with a clear atmosphere. Solution: The. gain due to transmitted solar radiation is found from Table 19 for Type I pattern. The factor for Type V is found from Table 20. The convection and radiation gain is found from Table 21 (note the footnote). The total instantaneous heat gain is, from Equation 2a, q = 88 X 0.65 + 26 X 1.4 - 92.3 Btu per (hr) (sq ft). Effect of Deviations from Design Conditions If the indoor temperature differs from 80 F, or the design outdoor dry-bulb temperature differs from 95 F, corrections can be made to the convection and radiation gain values for fiat glass, rolled figured glass, and glass block according to the schedule in Table 24. The effect of the humid industrial-type atmosphere is to cause a considerable reduction in heat gain, if all factors except solar intensity remain the same. Reference 22 gives heat gain values for four orientations at 40-deg north latitude on August 1 for several types of flat glass and glass block, and solar intensities typical of humid industrial atmospheres. These data show that the following approximate reductions, based on total gain for the day, can be expected: 20 percent ' for all types of glass and glass block in east or west facing walls; 10 percent for south facing flat glass; 5 percent for. south facing glass block walls. . Shading of Glass Areas--Shade Factors The shade factor is defined as the total gain from a shade- glass combination minus the convection and radiation gain from single unshaded common window glass divided by the total incident solar radiation transmitted by single unshaded common window gls In equation form, . (Total Gain from\ /Convection & Radiation \ Shade Glass J -- I Gain from Single ] factor Combination / \Unshaded Common Glass/ Total Solar Energy Transmitted by Single Unshaded Common Glass Design shade factors for a number of combinations are listed in Table 25. The total gain for a shaded window is found by multiplying the values of Table 12 by the appro priate shade factor and adding to these values the correspond ing values from Table 13. The values for sunlit windows are average values based upon calculations for several orientations. Actually the shade factor varies somewhat with orientation and time of day, because the proportion of direct to diffuse incident solar radiation as well as the profile angle varies. Generally these variations may be neglected. yhere are a number of variables affecting these ratios such as color, fit, solar altitude, and angle of incidence of the solar radiation. These values, therefore, must be considered as approximate, only, and will have to be used with consider able judgment. An inside shade is effective to the extent of its reflectivity, since the portion of the solar radiation directly transmitted by the glass that is absorbed by the shade is transferred by convection to the room air, and by radiation to the solid room surfaces. A more complete analysis of shade factors may be found in Reference 25. Roof Overhang, Canopies, and Other Horizontal Projections In some cases, a considerable reduction in heat transfer through windows can be attained by the use of a suitable horizontal projection. This is particularly true for S, SE, and SW orientations. In Table 26 are tabulated the required projections to produce a shadow height of 10 ft on a window or wall. The projection necessary for other shadow heights can be found by direct ratio. For example, a shadow height of 5 ft would require one-half the projection needed for a shadow height of 10 ft. Note that the table is for the period from April II through September 1. . The choice of projection should not necessarily be based on providing complete shading during all daylight hours. Reference should be made to Tables 12 through 15 to deter- V? Cooling Load 191 Table 19 .... Instantaneous Rate of Heat Gain Due to Transmitted Direct and Diffuse Solar Radiation by ' Unshaded Walls of 8-in. Hollow Glass Block of Type I Pattern For Chor Atmosphere* and 18 Deg Declination, North (August I) Note; For total instantaneous Seat gain add these vatue* to Table 21 vetoes tolftidi Sun Time AM --* i Instantaneous Hoot Gobi ia Btu per (hr) (*q ft) N NE E SE S SW W NW 30 Deg north 40 Deg north . 50 Deg north 6 a.m. 7 8 9 6 p.m. 5 4 3 10 2 1 12 5 a.m. 7 8 7 p.m. 6 5 4 93 2 1 12 5 a.m. 6 7 8 7 p.m. 6 5 4 93 2 1 12 4 45 55 12 2 2 5 59 94 29 4 3 5 42 94 38 5 4 5 25 59 34 6 5 6 12 27 24 9 6 6 8 12 13 10 . 7 6 67 898 1 3 3000 5 50 67 17 2 4 54 98 36 4 4 5 34 90 47 54 5 18 59 47 10 5 6 8 29 35 15 5 6 - 6 13 22 18 7 6 6 6 13 17 13 4 28 27 4 5 53 77 22 4 44 101 44 4 26 86 57 11 3 44 7- 4 5 12 57 60 16 5 5 6 29 54 25 6 6 6 14 34 32 10 6 6 6 20 34 20 2 3 4 5 6 6 7 0 4 4 5 6 6 6 1 4 4 5 5 6 6 2 4 5 6 6 6 0 4 4 5 6 6 6 1 4 5 5 6 6 T PM -- N NW W SW S SE NE mine during which hours of the day the solar gain is suffi ciently large to indicate the desirability of shading. This and the architectural practicability of the required projec tion should be deciding factors. INSTANTANEOUS HEAT GAINS VS. INSTANTANEOUS COOUNG LOADS The difference between instantaneous heat gain and in stantaneous cooling load has been mentioned previously; its practical importance is sufficient to warrant further consideration. Fig. 4 offers a simplified schematic illustration showing how the radiative part of the instantaneous heat The rwRafroo absorbed by the inferior furnishing* and stmetwo roaches the condifioasng eqaipmenf after a consderaMe delay in tine. Fig. A.... Origin of die Difference Between the Magnitudes of the Instantaneous Heat Gain and Instantaneous Cooling Load gain is first absorbed by solid objects, and is not encountered by the conditioning equipment as a cooling load until some later time, when it finally appears in the air stream entering the equipment. While it is true that some lag also is inherent in convective heat transfer and the time required to change the air in the conditioned space, this is usually of the order of a few minutp-Q to perhaps half an hour. Heat storage in the interior furnishings and structure increases according to the proportion of the instantaneous heat gain which is in the form of radiation, and also increases as the thermal capac itance of the objects and materials involved is increased. Constituents of the total instantaneous heat gain which have appreciable radiation components include those due to areas, exposed walls and roofs, lighting, appliances, and people. . A large difference in the time-incidence of the peaks be tween various spaces or parts of the same space indicates the necessity for zoning. In a building having an east and west exposure, where solar heat gains form a fair share of the cooling load, the timaa of individual zone peaks are apt to be some hours apart, and the peak load of one plus the off-peak load of the other will be substantially less than their combined peak loads. Proper zoning will permit operation to t*kpi full advantage of this condition or of similar con ditions of nonsimult&neous peaks, and will result in a lower total load and in savings in equipment. A factor gimil.r in effect and closely related to the non- 192 CHAPTER 13 1959 Guide Table 20 .... Instantaneous Rates of Heat Gain Due to Transmitted Direct and Diffuse Solar Radiation by Unshaded Walls of 8-in. Hollow Glass Block of Types II, HI, IV, IVA and V Patterns MnrtMv A. TWhU 1? Yahes fmf Typ- i hy Tkes; p-TM-*--- Pastors for Cfear Ahnojphere* and 18 Dog Dedinatron, North [August ?} For 30, 40, and 50 Dog North Latitude Note To obfem total fmtaatanoous heat goto odd adjusted Table 19 vafoat to the rafale 21 mfciat tiufuufaunou* Heat Gam Due to Tr as a Percentage of Type I Pattern . Son flow AM --. i 5 a.m. 6 7 8 9 10 U 7 pjn. 6 5 4 3 2 1 t PM -- . w, sw 100 100 100 100 100 100 100 100 N, NE, E,SE Type II fattens NE 100 100 95 95 90 90 95 90 95 85 95 . 95 100 95 100 100 NW W 100 90 90 90 90 95 95 100 SW S 100 100 100 100 90 95 100 100 s w, sw 70 70 70 70 70 70 70 70 N, NE, E SE Type tit fatten SE 70 70 65 65 65 60 65 65 65 65 70 70 70 70 70 70 75 NW w sw S 90 S Sun 77m AM --* i S a.m. 7 pan. 75 93 t PM --* Type (V Pattern Type IVA fattens N, NW, w, sw NE SE s N, NW, w, sw NE E SE S 55 45 35 75 55 55 45 35 55 45 35 80 55 55 35 55 45 35 '60 55 55 35 40 55 45 30 40 55 55 45 55 50 25 30 60 55 50 65 55 55 35 30 50 55 55 85 90 55 55 45 35 40 55 55 55 55 55 50 45 55 55 55 100 115 N, NE, E.SE NW w SW s N, NE, Ej SE NW W SW S 1 Sun Tim l 5 a.m. 6 7. 8 9 10 11 12 7 p.m. 6 5 4 3 2 1 Type V Pattern N, NW, W, SW NE E SE 60 35 35 30 60 35 35 30 60 35 40 35 60 50 65 50 60 . 80 90 90 60 70 105 105 60 60 80 110 60 60 60 85 S 60 60 60 60 60 90 105* 115* Designation of Block Type III--Light Diffusing --Ldzht J>ifiuaina IVA--Light Diffusing ' T PM - N, NE, E,SE NW W SW $ * Reduea by 30% (or 30 dec N latitude only. simultaneous occurrence of. peak loads, is diversity. Typical of this is the case of a large department store where the air handling equipment serving a certain space must be sufficient to handle the load created by the throngs of people attend ing sales in that space. Under such a condition the number of people in other spaces is usually normal or below. While this means that the air-handling equipment for certain departments must be large enough to cope with the situation, the refrigeration equipment need be only large enough to handle the average maximum. If a system employing zone recirculating fans and a single central fan and dehnmidifipr were used, the saving would be reflected in the capacity of the central fan and dehumidifier. Another example of this diversity is found in an office building having restaurants and stores of certain types in the first story and basement. Cooling Load 193 Table 21.... Instantaneous Rates of Heat Gain by Convection and Radiation from Unshaded Wails of 8-in. Hollow Glass Block of Patterns Type I, II, 111, IV, IVA and V* For Clear Atmospheres and 18 Dag PocEncticn, North [August I) For 80 P Indoor Temperature . Note For Mol iiutonlcneoa* heal gam odd these values to values in Table 17, or Tabla 19 adjusted by Table 20 factor* Sun Tim Dry-Mb Fate. latitude ' N Instantaneous Heat Gain m Btu per (hr) (*q ft) NE Sf s sw w 6 7 8 9 10 11 12 2 .3 4 5 6 7 -8 9 74 -3 -3 -3 -3 -3 -3 -3 74 0 3 4* 3 -2 -2 -2 75 1 15 17* 13 -1 -1 -1 77 0 21 26* 21 1- 0 0 80 0 20 33 27 5 1 2 83 2 12 36 32 12 3 3 87 4 6 29 32 19 5 6 90 40 6 8 16 28 23 9 8 93 Degrees 8 10 14 14 26 25 12 94 North 9 10 15 11 25 37 28 95 11 11 16 11 21 44 41 94 11 11 15 11 16 45 44 93 11 10 13 10 13 43 42* 91 13 9 11 9 11 35 35* 87 11 . 7 8 7 8 19 21* 85 7 4 4 4 4 7 7 83 4 3 2 3 2 3 4 NW -3 -2 -1 0 1 3 5 7 9 11 17 30 35 29 15 4 3 Sun Tim Dry-Sulfa latitude SE S SW latitude SE S SW 6 7 8 9 10 11 12 . 1 p.m. 2 3 4 5 6 7 8 9 74 74 75 77 80 83 87 90 93 94 95 94 93 91 87 85 83 30* Degrees North -3 1 11 20 26 29 26 18 io- 11 12 12 11 . 10 6 4 3 -3 -2 -1 0 1 4 8 12 15 16 14 13 11 9 6 4 3 -3 -2 --1 0 2 4 5 7 16 30 39 43 41 32 15 6 3 50* Degrees North -3 -3 -3 5 -2 -2 13 -1 -l 21 0 0 27 6 1 32 15 2 35 22 4 33 28 17 23 31 31 12 32 39 11 28 43 11 20 44 10 12 43 9 10 36 7 7 23 4 4 10 333 * For types HI. IV, IVA sad V patterns end 30, 40 end 50 deg latitudes, multiply seat w&Q values (or 0, 7 sad 6 s.m. by 1.40, sad west wall values for 5, 0 and 7 pjn. by 1.25. * For N, NE. E, W and NW use 40 deg North Latitude values. . At noon, when the restaurants and stores are crowded, the offices are below normal occupancy. ' Heat lag should be carefully considered in the cooling load calculations. In certain types of buildings the effect of solar radiation is still apparent several hours after the sun has shifted from that exposure. In other types having a much ,lighter construction, the heat gain due to solar radia tion decreases markedly with the passing of the sun. Some walls, warmed by the sun, may radiate heat long after the passing of the sun, thus requiring lower indoor temperatures to offset the radiant energy. - Buddings have considerable heat storage capacity which can often be utilized to great advantage, and which has. provided an unexpected safety factor in many installations. If a space is kept below the design indoor temperature for some time, the interior walls, floors, furniture, and fixtures begin to assume the temperature of the space. Where the time is sufficient the' entire mass, 'rather than merely its surface, may reach the room temperature. Thus, when a space has been precooled below the design maximum tem perature for a period of time prior to the advent of the peak load, and the heat gain begins to increase to peak conditions, some of the increase is used in raising the temperature of the furniture, fixtures, etc., to the design conditions and the cooling load can be reduced accordingly. However, unless very accurate data with regard to the mass, surface, specific heat, etc., of the items within the space are available, due caution must be used in discounting the cooling load for this storage effect. In the absence of reliable data this allowance is often a matter of experience rather than calculation. 194 CHAPTER 13 1959 Guide Table 22 . -- Instantaneous Rates of Heat Gain Due to Transmitted Direct and Diffuse Solar Unshaded Skylights of Hollow Glass Block of Types VI and VII Patterns For Char Almotphorot and 18 Oeg Oecfinafion, North (Auguxf I) Not*: For total fattantoneam boot gain add thta ratuei to Table 23 vafoes Radiation by in 6to par (hr) (tq ft)* Sun Tom 5 a.m. 6 7 8 7 p.m. 6 5 4 Typo VI North Latitude . 30 40 50 001 3 .4 4 7 8 '7 11 13 14 93 20 2 11 1 12 19 19 20 29 23 22 38 26 23 37 27 22 * Valaee for Type VI are for [nl ae aaeembtod. Velaee for Type Vll are far glaee Typo VTI North latitude 30 40 00 34 10 11 19 19 31 29 41 38 49 44 52 46 only. See text. 50 1 5 11 18 26 33 38' 39 Sun lime 5 a.m. 6 7 8 7 pjn. 6 5 4 93 10 2 11 1 12 Table 23 .... Instantaneous Rates of Heat Gain by Convection and Radiation from Unshaded Skylights of Hollow Glass Block of Types VI and VII Patterns For Clear Atmosphere and 18 Oep OacErrifiM, North (Aogod f) For 80 F Indoor finiii)iiunfiiio Wolgs For total imtontonaoui hoof gain, add these wsfaea to Table 22 vaftres____________ Inrtonfonoout Heal Gain in 8lw per (M {*q ft)* Sun T7me 5 a.m. 6 7 8 Typo VI North latitude 30 40 50 -9 -9 -9 -9 -9 -9 -9 -9 -8 -7 -5 -4 Typo VI/ North latitude 30 40 -9 -9 -9 -9 -9 -9 -7 -7 9 4 5524 10 14 14 13 11 11 11 21 21 19 *16 16 12 29 27 25 20 20 1 p.m. 2 3 4 34 32 29 25 23 37 34 31 27 26 37 35 32 28 28 34 32 29 26 25 5 29 28 26 24 23 6 22 22 22 20 20 7 14 14 14 13 13 * Valaee far Type VI are for pond ae arurmbled. Values far Type VU an for gbes Mn-t only. See text. 50 -9 -9 -9 -5 4 11 15 17 22 24' 25 22 22 19 13 Son Tine 6 7 8 9 10 11 12 2 3 4 5 6 7 Table 24 .... Approximate Corrections to Tables 13 and 21 for Deviations from Indoor and Outdoor Design Temperatures For aeh degroe the design room toeiperatare exceeds 80 F, mbfroct cor rection.* For eadi degree (ho deagn outdoor dry-bulb temperature exceeds 95 F, add correction." Apply these corrections to each value fa Table 13 or Table 21. ' Glass Typo Correction - 8fu per (hr) (sq ft) Single flat or rolled figured glass Doable fiat glass aod glass block 1.0 0.5 If tempenta b ksi than 80 F, add correction. b if temperature b km than 03 F, subtract correction. Where air-conditioning supply and return ducts pass through unconditioned spaces, there will be a transfer of heat from these spaces to the air in the ducts, even though these ducts are well insulated. An allowance should be made for (his heat gain and included in the heat estimate bo that air can be supplied at a temperature low enough to offset the rise caused by this heat gain (see Chapter 21). There will also be some heat gain to the air in ducts pairing through conditioned spaces, but since a cooling effect is produced in the space through which the duct paggp^ this is not a loss and usually can be compensated for by adjustment of air quantities between the various spaces. No comprehensive data are presently available for use in deagn load estimates to evaluate the interior load-lag Cooling Load Table 25____ Shade Factors for Various Types of Shading Type of Sbodfag Flaith on Side Expowd to Sun Canvas awning sides open Canvas awning top ana sides tight against building Inside roller shade, fully drawn* Inside roller shade, fully drawn* Inside roller shade, fully drawn* Dark or medium Dark or medium White, cream Medium Dark Inside roller shade, half drawn* Inside roller shade, half drawn* Inside roller shade, half drawn* Inside Venetian blind, slats set at 45 deg*1 Inside Venetian blind, slats set at 45 degb White, cream Medium Dark White, cream Diffuse reflecting aluminum metal Inside Venetian blind, slats set at 45 deg* Inside Venetian blind, slats set at 45 deg6 Outside Venetian blind, slats set at 45 degb Outside Venetian blind, slats set at 45 deg6* * extended as awning fully covering window Outside Venetian blind, slats set at 45 deg, extended as awn ing covering of window* Medium Dark White, cream White, cream White, cream 195 0.25 0.35 0.41` 0.62 0.81 0.71 0.81 0.91 0.56' 0.45* 0.65* 0.75' 0.15* 0.15* 0.43 Outside shading screen, solar altitude 10 deg Outside shading screen, solar altitude 20 deg Outside shading screen, solar altitude 30 deg * Outside shading screen, solar altitude, above 40 deg 0.46 0.35 0.24 * Roller ore assumed to be opoqoe. ft""* white may transmit considerable color radiation. Far white translucent shades fully drawn use 0 55 and (or half drawn use 0.77. . b Venetian are folly drawn afa cover window. It is ?-----ri nt the occupant will adjust slats to prevent direct toys from peicritu between slats. If -*- ore fully Hrwr* (data set at 00 A-t) use same factors as used for roller shade fully drawn. * --i shade with wide Tim son may shine on window through sides of shade. Estimate the exposed portion of duo as unshaded. * Commensal shade, bronse. Metal slats 0 05 inches wide 17 per ineh and set st 17 dec ancle with horisontal. At tolar altitudes below 40 dec some direct solar rays are allowed lo pass between slots, and this amount becomes procrcerivdy creater at lew solar altitudes. * aluminum +W- Slats 0.057 i~4>-- wide. 174 per inch, set et 17 dec and with horisontal- At solar altitudes below 40 dec eome direct solar rays are allowed to post between slats and this amount becomes progressively creater at low solar altitude. * From first paper in Reference 2$. effect, but several investigaters1^ " ** ** " have made a study of (he problem and. have presented many useful data:' Tables 9, 10, 12, 13, 17, 19, 20, 21, 22, and 23 are all based on instantaneous rates of heat transfer. Hence, practical judgment and experience offer the only basis of procedure. Until the needed data become available, it is recommended that the noncontinuous load be averaged over two or three hours during the time of mnYimum load, when determining the total instantaneous cooling load where a large portion of the heat gain is radiant. This suggestion applies only to conditions near the time of maximum heat gain, as the heat stored within the structure would necessarily appear in the cooling load eventually; but if it appears at a time when the gain from outdoors is relatively low, the equipment will be able to maintain satisfactory conditions within the range of maximum capacity. LOAD FROM INTERIOR PARTITIONS, CEILINGS, AND FLOORS Whenever a conditioned space is adjaoent to another space in which a different temperature prevails, the transfer of heat through the separating structural section must be considered. Calculations are made according to the relation: where q = UiAi(th -- f<) Btu per hour. (6) ..Table 26 .... Length of Horizontal Projection Required for Shading Windows and Wails For Shading 10 Ft Doom From Proportion For April It Through Sephnbw I Sun Time Projection fa Foot latitude AM--* 1 N NE E SE 5 sw 40 Deg 50 Deg 6 a.m. 7 8 9 10 11 12 6 p.m. 5 4 3 2 1 5 a.m. 6 7 8 9 10 11 12 7 p.m. 6 5 4 3 2 1 5 a.m. 6 7 8 9 10 12 7 p.m. 6 5 4 3 2 1 17.4 5.6 2.0 0.6 __ __ -- * 11.2 6.3 3.3 1.1 -- a * 17.4 10.8 6.3 3.1 -- * 13.8 9.7 7.1 4.7 2.9 . 12.0 3.5 __ -- __ -- -- 8.4 1.6 __ --_ __ -- ' * 9.7 18.9 4.7 11 2 1.3 6.5 -- 3.1 ---- a- 9.4 19.7 3.1. 12.8 _0.6 7.6 3.7 ---- 16.1 11.6 9.1 6.5 4.3 * 18.9 14.3 11.6 8.7 6.6 _ __ 0.9 -- 2.6 -- 3.6 -- 3.9 -- 4.1 0.9 4.1 2.9 __ ---- 1.8 -- 4.3 -- 8.4 -- 5.8 -- 6.1 2.2 6.3 4.3 _-- ---- 3.7 -- 6.6 -- 7.9 -- 8.4 0.6 8.7 3.9 9.1 6.5 U{ -- coefficient of overall heat transfer between the adja cent and the conditioned space, Btu per (hour) (square foot) (Fahrenheit degree). ' t P M --* N NW W sw s SE * Projection (motor than SO ft required. jfS W" 196 CHAPTER 13 1959 Guide At = area of separating section concerned, square feet, ft *= air temperature in adjacent space. Fahrenheit. U air temperature in conditioned space, Fahrenheit. Magnitudes of U> may be obtained from Chapter 9. The temperature W may have any value over a considerable range, according to conditions in the adjacent space. The temperature in a kitchen or boiler room may be as much as 15 to 60 deg above the outdoor air temperature. It is recom mended that actual temperatures be measured in adjoining spaces wherever practicable. Where nothing is known, except that tiie adjacent space is of conventional construction and contains no heat sources, it is recommended that the differ ence (k -- ti) be taken as the difference between the outdoor air and conditioned-space design dry-bulb temperatures minus 5 deg. In some cases it may be that the air temperature in the adjacent space will correspond closely to the outdoor . air temperature at all times. Under these Utter conditions, the heat gain through the partition will be periodic in nature, and the value of a ahadad wall should be used from Table 10. For floors directly in contact with the ground, or over an underground basement that is neither ventilated nor warmed, the heat transfer may be neglected for cooling-load estimates. LOAD FROM OUTDOOR AIR, VENTILATION, AND INFILTRATION Ventilation. Data for determining the necessary ventilation rate have been presented previously in this chapter. Ventila tion required is primarily dependent upon the number of occupants and upon the materials and apparatus within the space which may give off odors. For spaces having ceiling heights 10 ft or less, the total requirement should be checked against the volume, and in no case should the ventiUtion air rate be less than one air change per hour. In, spaces having ceilings higher than 10 ft where the occupant load is low, a check calculation can be made against the volume of the space below an assumed 10-ft ceiling. Infiltration must never be counted upon to provide venti lation, because on still days there will be littie or no infiltra tion. Infiltration. The principles of infiltration calculations have been discussed in Chapters 11 and 12, with emphasis on the heating season. For the cooling season, infiltration calcula tions are usually limited to doors and windows. To compute cooling-load infiltration for windows by the crack method, use the data of Table 2, Chapter 11, for a wind velocity of 10 mph. Note that for double-hung windows . the length of crack is three times the width plus twice the. height; while for metal-sash windows the crack length is tile total perimeter of the movable or ventilating sections. In calculating window infiltration, for an entire structure, it is not necessary to consider the total crack length on all sides of the building, for the wind would not act simultaneously on ail sides at once. In no case, however, should less than half of the total crack length be figured. A knowledge of the prevailing wind direction will aid judgment in this con sideration. - Cooling-load infiltration for doors2* may be obtained from Table 3, Chapter 11. For conditions other than those covered, the notes appended to the table will provide a basis for esti mates. The tabulated data may also be used as the basis of estimates for interior doors between an air-conditioned and a non-air-conditioned space. Infiltration load must be included whenever the new air introduced through the system is not sufficient to maintain sufficient pressure within the enclosure to prevent the in filtration. Whenever economically feasible, it is desirable tr> introduce sufficient outdoor air through the air-conditioning equipment to maintain a constant outward escape of air, and thus eliminate the infiltration portion of the load. The pressure maintained must be sufficient to overcome wind pressure through cracks and door openings. When this con dition prevails it is not necessary to include any infiltration load. When the quantity of new air introduced through the cooling equipment is not sufficient to build up the required pressure to offset infiltration, the entire infiltration load should be included in the cooling load calculations. Total Outdoor Air Load. Many cooling coil manufacturers publish tables giving psychrometric data based on the average conditions of the leaving air for various coil temperatures, air velocities, and entering dry-bulb and wet-bulb conditions. When these tables are used, it is necessary to calculate the mixed-air condition entering the coil, and determine from the tables what coil and air velocity will produce the desired leaving-air conditions as required for the space to be con ditioned. When cooling coils are listed as 80 to 95 percent efficient, the manufacturer indicates that 20 to 5 percent of the air passes through the coil without being cooled. If data of this nature are used, the uncooled portion of the air must be added to the space load before determining the effective air quantity. See later section on Apparatus Dew Point. To determine the design cooling load caused by the intro duction of outdoor air, the maximum rate of outdoor-air entry is first established. In some applications the use of special exhausters from the conditioned space may add to the outdoor-air requirements in determining the maximum rate. When thiq design quantity is established, and the design indoor- and outdoor-air states are known, the cooling load may be computed. There are several methods in use, the more accurate of which require rather detailed calcula tions. Refer to Chapter 3, and also section on Apparatus Dew Point in this chapter. The following equations are considered to be of sufficient precision for use at usual design conditions, as their accuracy is within 1 percent. Sensible Load q, * Q X 60 X 0.244 a Q X 1.08 (f# -- <*), Btu per hour (7) Latent Load 9. - Q X 60 X 0.075 X 1076 (ff\ - W\) =* .Q X 4840 (W, -- Wi), Btu per hour (8) Total Load where 9 - 9. + 9 ' (9) Q = rate of entry of outdoor air, cubic feet per minute. t " outdoor dry-bulb temperature, Fahrenheit. U =* indoor dry-bulb temperature, Fahrenheit. W, =* outdoor humidity ratio, pounds moisture per pound of dry air. W{ <= indoor humidity ratio, pounds moisture per pound of dry air. .. 0.075 " standard air density,' pounds per cubic foot. 0.244 " a constant approximating the specific heat of dry air corrected for moisture, Btu per (pound) (Fah renheit degree). Cooling Load 197 1076 " a factor approximating the average Btu released in condensing one pound of water vapor from air. As explained later in the section on Apparatus Dew Point, some methods of load calculations break down the ventila tion air into two parte: one portion which does not contact ' the coil surfaces (i.e., bypasses the coil) in passing through the coil and thus becomes a part of toe room load; and a second portion, the remainder of. the air which contacts the coil surfaces and is cooled down to the apparatus dew point. This detailed method explained in the literature by Ashley,M is believed to be very easy arid accurate to use. Similar equations, therefore, can be written: Space Sensible Ventilation Load, - Q X 1.08 (t. - U) X 6 (10) Space Latent Ventilation Load, q.i m Q X 4840 (W. - Wt) X 6 (11) Remaining Sensible Ventilation Load, 9 - Q X 1.08 (f. - td (1-6) ' (12) Remaining Latent Ventilation Load, _ where jo-QX 4840 (17. - Wi) (1 - 6) 5< = q*i 4- q*M + + qa ' (13) (14) 6 = fraction of air passing through coil which does not'eon- tact surfaces, coil bypass factor. ' Standard air weight (0.075 lb per cu ft) is recommended for use in all calculations, as this is the basis for rating fans and its consistent use keeps all parts of the calculations in con formity. HOW OUTDOOR AIR LOAD AFFECTS ROOM LOAD _ Actually, the outdoor air used for ventilation would pass through toe conditioning equipment, and be cooled and de- : humidified to a lower temperature and humidity ratio than room conditions before entering the room; but for heat- balance purposes the cooling load chargeable to the outdoor air is that corresponding to the difference between toe out door and indoor air conditions. * One important purpose of the cooling-load estimate is to determine toe conditions and quantity of air supplied to the space. All the various sensible and latent heat loads within the space must be included. Infiltration must be included in the space load since this air enters the doors and windows, and its heat and moisture load must be offset by toe intro duction of cooler, dryer air to the space. However, since outdoor air is taken through the conditioning equipment and cooled, this portion does not become a part of the space load, except a amah portion which passes through the coil untreated. To determine the total load on the refrigeration, machine, the remaining outdoor-air load must be included in tile grand total load. Example 10: For outdoor design conditions of 95 F dry-bulb and 75 F wet-bulb, and indoor design conditions of 80 F drybulb and 67 F wet-bulb, and for the supply of outdoor air at the rate of 1000 cfm and the exhaust of room air at the corre sponding rate, calculate the total, sensible, and latent heat gains. Solution: Substituting in Equation 7: q. = 1000 X 1.08 (95.- 80) = 16,200 Btu per hr. From psychrometric data Wt = 0.01413, Wi -- 0.01122. Substituting in Equations 8 and 9: q. = 1000 X 4840 (0.01413 - 0.01122) = 14,100 Btu per hr. 9* " 9 + 9. * 30,300 Btu per hr. HEAT SOURCES WITHIN THE CONDITIONED SPACE People. The rates at which heat and moisture are given off by human beings under different states of activity are given in Table 27. In many applications these.sensible and latent heat gains become a large fraction of the total load. Appreciable variations in heat-emission rates must be recog nized according to the age and sex of the individual, state of activity, environmental influences, and duration of occu pancy (since for short occupancy the extra heat and moisture brought in by people may be a significant factor). While Chapter 6 should be referred to for detailed informa tion, Table 27 in this chapter summarises practical data representing conditions commonly encountered. Lighting. In general, the Instantaneous rate of heat gain from electric lighting*1 may be calculated from the following relation: {total light wattage fuse (special allow\factor * \ance factor (15) X 3.41, Btu per hr. The total light wattage is obtained from the ratings of all fixtures installed, both for general illumination and for dis play use. - The use factor is the ratio of the wattage in use, for the con ditions under which the load estimate is being made, to the total installed wattage. For commercial applications such as stores, the use factor would be unity. The special allowance factor is introduced to care for fluores cent fixtures, and for fixtures which are either ventilated or installed so that only part of their heat goes to the conditioned space. For fluorescent fixtures, the special allowance factor is recommended to be taken as 1.20 in order to allow for power consumed in the ballast. For ventilated fixtures, recessedfixtures, and the like, manufacturers' or other data*1 must be sought to establish the fraction of the total wattage which may be ex pected to enter the conditioned space. '. Power. When equipment of any sort is operated within the conditioned space by electric motors, the heat equivalent of this operation must be considered in the cooling load. The general equation for calculating this load is: (9-- Horsepower Rating\ Motor Efficiency / `/Load \ X 2544, Btuh VFactor/ (16) It is asBiimed that both the motor and the driven equipment are within toe conditioned space. If the motor is outside tiie space, then do not divide by the motor efficiency in Equation 16. The load factor is merely the fraction of the rated load which ts being delivered under the conditions of the cooling load estimate. Motor efficiencies may be approximated as follows: about 50 to 60 percent at )>& hp rating, increasing to 80 percent at 1 hp, and to 88 percent at 10 hp and above. Appliances. Care must be taken in a cooling-load estimate to take into account toe heat gain from all appliances, elec trical, gas, or steam. Table 28 presents recommended data.** Note that toe maintaining rate in Table 28 is the heat input required to maintain the appliance at the normal operating temperature even though it is not being used, i.e., no coffee is being made, no toast is being made, no food is being cooked in the fry kettle, etc. The maintaining rate is useful in setting W 198 CHAPTER 13 1959 Guide Table 27 .... Rates of Heat Gain from Occupants of Conditioned Spaces* Oogroo of Activity Typioat Appikatha Total Heal Aduttt. Total Hoc* AdMala Btu/Hr judodb Btu/Hr SenaUe Hoot Btv/Hr Latent Hoot Bio/Hr Theater--Evening............. Seated, very light work................................ Offices, hotels, apartments Moderately active office work.................... Offices, hotels, apartments Standing, light work; or walking slowly.. Department store, retail store, dime store........... Standing; walking slowly............................ Sedentary work................................................ Restaurant*........................ Light bench work............................................ Factory................................ Moderate dancing........................................... Dance hall.......................... Walking 3 mph; moderately heavy work.. Factory................................ 390 450 475 550 550 490 800 900 1000 350 400 450 450 500 550 750 850 1000 195 .195 200 200 200 220 220 245 300 155 205 250 250 300 330 530 - 605 700 Heavy work...................................................... Factory. .. ....................... 1500 1450 465 985 * Ifdo:Tikstatod values inbawd oo 80 F room dry-bulb temperature. Fer 78 F room dry-bulb, tbe total heat remihi the amt, bat the eeuible beat value! should be increamd by approximately 10 percent, aad the latest heat values decreased aceordiotly. ' k Aijuttoi total Met oin a hased on normal percentage cd men, women, aad children lor the application lifted, with the postulate that tlw caio from an adult fe male is 85 percent of that (or aa adult male, and that the gain from a child is 75 percent of that fee an adnlt male. 'Adjusted total heat value for ttAsnlary wot*, rastosma/, includes 60 Btu per hour for food per individual (SOBtu eeniible and 30 Btu latent). d For hawh'ar figure one person per alley actually bowling, and all others as sitting (400 Btu per hour) or (SS0 Btu per hour). up a lower, limit to the heat gain to a room from the appli ance when in operation. Experienced judgment must be used in the application of data given in Table 28. Consideration must be given to the heat contributed by appliances which are in use at the time of peak load. The quantity of heat will depend upon whether products of combustion are vented to a flue, whether they escape into the space to be conditioned, or whether appli ances are hooded to allow part of the heat to escape through a stack. There are no generally accepted data available on the effects of venting and shielding halting appliances, but it is believed that when they are properly hooded with a positive fan-exhaust system through the hood, 50 percent of the heat will be carried away and 50 percent dissipated in the space to be conditioned. In the case of gas-burning appliances where the heat of combustion adds considerably to the total heat output, it is believed that a well-designed hood will remove more than 50 percent of the heat generated at the appliance. The same effectiveness of the hood should be figured for both latent and sensible heat. . For each meal served the heat transferred to the dining space is approximately 50 Btu per hr, of which 75 percent is sensible and 25 percent latent. Heat gains from cooking appliances, motors, lights, and people are not considered in cooling load calculations if the appliances are located in a separate kitchen that is not part of the conditioned area. . LOAD FROM MOISTURE TRANSFER THROUGH PERMEABLE BUILDING MATERIALS The diffusion of moisture through all common building materials is a natural phenomenon which is always present to a greater or lesser degree. The permeability and permeance values for various build ing materials are given in Table 2 of Chapter 10, together with an explanation of moisture transmission through these materials. In the usual comfort air-conditioning application, it iB common practice to neglect moisture transfer through walls, because the actual rate is quite small and the corresponding latent-heat load is hardly significant. Vapor barriers are frequently employed in modem construction for the purpose of keeping moisture transfer to a minimum, and reducing the deteriorating and insulation-destroying effects of moisture. Industrial jobs, on the other hand, frequently call for a low moisture content to be maintained in a conditioned space. Here the matter of moisture transfer cannot be neg lected; indeed, it is quite possible to have the latent-heat load accompanying this transfer be of greater, magnitude than any other latent-heat load. The equation for computing this load is: where (KX) >< . TM M -- permeance of the specimen in perms, or grains per (square foot) (hour) (inch of mercury vapor-pressure difference). . 7000 = grains per pound. The factor 1076 is de6ned in list of symbols at Equation 0. (Sensible cooling of the water vapor is included in the factor 1076.) . The only means of preventing moisture transfer, is to use a vapor proof wall, or to apply a special lining, which is Cooling Lood 199 vapor proof. All openings in moisture proof construction must be equipped with special gaskets to prevent entrance of moisture. When moisture transfer contributes an appreciable part of the latent-heat load, it is recommended that estimates should be made intentionally liberal in order to avoid later difficulties with insufficient dehumidifying capacity. Storage spaces, for example, would require sufficient dehumidifying capacity to handle the moisture brought in with goods to be stored, in addition to moisture leaking in subsequently. MISCELLANEOUS HEAT LOADS This designation is intended to cover the various small heat gftma from exposed piping, ducts, work done by circu lating fan, and unforeseen contingencies. Where sufficient data are available, these various heat gains may be estimated individually. In the majority of cases, however, common practice is to lump these factors together and combine them with a safety factor according to the experience and judgment of the estimator. On this basis, a small safety factor is added to the calculated cooling load to compensate for miscellan eous effects. No rules can be given for this procedure, as experience in air conditioning is indispensable for applica tion of suitable safety factors. air is passed through, the room sensible-heat gain and room Latent heat gain will be changed due to the addition of un treated outdoor air which changes the enthalpy-humidity difference ratio. When a load calculation is made, it is neces sary to know the percentage of air treated in the dehumidifier, and calculation must be made accordingly. If the ventilation air is drawn through the dehumidifier before it goes into the room, only that portion of the air not saturated must be included in the room load for the purpose of determining the apparatus dew point and supply-air quan tity. It should be noted when evaluating the load added by untreated outdoor air that the temperature difference be tween room air and outdoor air, and the moisture content difference between room air and outdoor air, should be used, rather than the difference between outdoor air and apparatus dew point, since the rise from the apparatus dew point to room condition is charged against the dehumidifier as the cooling and dehumidifying load. APPARATUS DEW POINT AND REQUIRED AIR QUANTITY THROUGH CONDITIONING EQUIPMENT In ordinary practice, with commercial apparatus, complete saturation of the air is seldom obtained. Four-row finned cooling coils contact approximately 80 percent of the air, whereas six-row finned coils contact approximately 95 percent of the air. In spray-type dehmnidifiere of good design the air leaves the dehumidifier at 1 to 2 deg higher wet-bulb temperature than the spray water leaving the dehumidifier, the difference between the dry-bulb and wet-bulb tern-'- peratures leaving the dehumidifier may be as low as 1 deg. Fig. 5____Apparatus Dew-Point Shown on ASHAE Psychrometric Chart A spray-type dehumidifier having sufficient length of spray ' chamber and density of spray, together with proper arrange The procedure for determining the required air quantity ment of nozzles, may approach saturation very closely. is based upon the thermodynamic principles of Chapter 3 As explained in Chapter 3, and shown in fig. 5, the slope and the use of the ASHAE Psychbometbjc Chabt. Readers of the Hnft on the psychrometric chart connecting the room are advised to review these principles, paying particular condition with the apparatus dew point on the saturation attention to the illustrative examples. line, determines the ratio of sensible heat absorbing capacity Calculation of the cooling load for a conditioned space is to the moisture absorbing capacity of the supply air. There equivalent to making, for the space, a heat balance in which fore the room condition can be maintained as long as the all heat, moisture, and infiltration are treated as directly supply-air temperature lies on this line, but a greater volume entering the space. As *>yplaind in the section, Load from of supply air must be used to satisfy the room lead if the Outdoor Air, Ventilation, and Infiltration, the outdoor-air cooling coil does not contact 100 percent of the air. For a normally does not become a part of the space load, be given room load, the same apparatus dew point will be re- cause heat and moisture are removed in the air conditioner quired whether the cooling appliance contacts all the air or . before this air gets into the conditioned space: The desired only part of the air. - conditions are maintained by considering a certain quantity From the point of view of satisfying the given cooling load of air to be withdrawn from the space, passed through the requirements, the air passing through the apparatus without conditioning equipment, and returned to the space with such being cooled below the dew-point temperature produces two a temperature and humidity ratio that its net effect will be effects: to counterbalance or remove the given entering amounts of 1. The air quantity which must be passed through the de humidifier must be increased. Thus, if 20 percent of the air passing is not contacted, then (20 -4- 80) X 100 = 25 percent more air must be used than would be necessary if all of it were contacted. - heat and water vapor. This quantity of indoor air, which is considered bo be circulated in this manner, is called the required air quantity and its determination is normally part of every cooling-load estimate. The procedure is as follows: 2. Passing untreated air may change the room cooling load, which in turn may change the enthalpy-humidity difference ratio (sometimes called the sensible-heat factor). If return air only is passed through the dehumidifier or if room air only is bypassed, the room load will not change, but if some outdoor 1. Determine the total sensible and latent heat loads in Btu per hour for tbe space. 2. Compute the quantity called the enthalpy-humidity difference ratio (also, referred to as heat-moisture ratio) of 200 CHAPTER 13 1959 Guide Toblc 28-------Rote of Heat Gam From Appliances WITHOUT HOODS**b AppGooc* Copodty Overall DrmeraioRt (lea Lags and Handle*; Lett Dimension it Height) Inches Control ^. mat M-- Manuel Miscellaneous Data 55 Bt/Hr Mnln. Recommended Kate of Heat Gain 0fv per Hoar Rato Hour Sensi ble latent Total fedwaaf Boctricol Appliances Coffeeybrewer and wanner Coffee brewer unit with tank Coffee urn Doughnut machine Egg boiler Kgal Hgal 3 gal5 gal 2 cups M Brewer 660 w M Warmer 90 w ' 20 x 30 x 26 2000 w Water heater, 2960 w brewer 12 x 23 x 21 A 18 (Diam.) x37 A Nickel plated Nickel plated 22 x 22 x 57 A Exhaust system 10 x 13 x 25 M Food wanner, with plate warmer, per sq ft of top surface Food warmer, alone, per sq ft of top surface Insulated, separate A heat unit for each pot; plate warmer in base A Fry kettle Fry kettle Griddle, frying Griddle, frying Grill, meat Grill, sandwich Roll warmer Toaster, continuous Toaster, continuous Toaster, pop-up Waffle iron UM lb fat 12 (Diam.) x 14 25 lb fat 16 x 18 x 12 18 x 18 x 8 24 x 20 x 10 14 x 14 x 10 13 x-14 x 10 23 x 23 x 29 360 slices/hr 15 x 15 x 28 720 slices/hr 20 x 15 x 28 216 slices/hr 12 x 11 x 9 20 waffles/ 12 x 13 x 10 hr A A A A A A A A A A A Area 12 x 14 in. Area 18 x 14 in. Area 23 x 18 in. Area 10 x 12 in. Area 12 x 12 in.' Threp drawers 2 slices wide 4 slices wide 4 slice 7 in. diam. waffle 600 90 4960 4500 5000 4700 1100 400 300 2600 7000 2350 4000 3000 1650 1000 2200 3000 2450 750 2000 300 17000 900 220 306 230 60 4800 1200 15000 2600 2200 1500 17000 3600 3400 2300 16000 5000 0 3750 1200 800 1350 500 350 350 1000 . 400 200 350 8900 1100 1600 2400 24000 2000 3800 5700 8000 2800 3100 1700 13500 5000 5300 2900 10250 1900 3900 2100 5000 1900 2700 700 3400 900 2400 300 7500 5000 5100 1300 10250 6000 6100 2600 8400 2000 4900 900 2500 600 1100 750 1120 290 6000 3700 5700 5000 2000 700 550 4000 9500 4800 8200 6000 3400 2700 6400 8700 5800 1850 Restaurant Gat-Sumtng Appliances Coffee brewer and H ga> warmer Coffee brewer unit 4H gal Tank 19 x 30 x 26 with tank M Brewer M Warmer, - - 4 Brewers and tank Coffee urn 3 gal 5 gal Food Warmer, oer sq ft of top surface 12 x 23 x 21 A 18 (Diam.) x 37 A Nickel plated Nickel plated M Water bath Fry kettle Fry kettle Grill 15 lb fat 28 lb fat 12 x 20 x 18 15 x 35 x 11 22 x 14 x 17 A Area 10 x 10 A Area 11 x 16 M Insulated, grill sur face of 1.4 sq ft Top burner 22,000 Btu/hr Bottom burner 15,000 Btu/hr 3400 500 1350 350 500 400 100 7200 1800 1700 500 9000 3400 2500 2500 4700 3900 3900 2000 900 850 430 5000 7800 1280 14250 3000 4200 2800 7000 24000 4500 7200 4800 12000 37000 14400 3600 18000 Cooling Load 201 Table 28____ Rate of Heat Gain From Appliances WITHOUT HOODS'-b (Conduded) AppConca Capacity Overall Dimensions (ten legs and Handles/ last Dimension is Height) Inches Control A-- Auto- M-- Mjc*0oneotr* Dote factow't Sating Watt* Blu/Hr Main Recommended Sat* of taining Heat Gain Btu per Hour Kate Hour bU Latent Total Kestouront Gat-Burning Appliances--Cuntim/ed Stoves, short order Open top, per sq ft top Closed top, per sq ft top Fry top, per sq ft top Toaster, continuous 360 slices/hr 15 x 15 x 28 Toaster, continuous 640 slices/hr 20 x 15 x 28 M Ring type burners ' M Riog type burners M Tubular type burners A 2 slices wide A 4 slices wide 14000 4200 11000 3300 12000 3600 12000 10000 7700 20000 14000 12000 4200 3300 3600 3300 5000 8400 6600 7200 11000 17000 . Coffee urn 3 gal 5 gal Coffee urn 3 gal 5 gal Food warmer, per sq ft of-top surface Food warmer, per sqft of top surface - Rettoorant Steam-Heated Appliances 12 x 23 x 21 T 18 (Diam.) x 37 T Nickel plated' Nickel plated 12 x 23 x 21 M Nickel plated 18 (Diam.) x37 M Nickel plated T M 2400 1600 3400 2300 2600 2600 3700 3700 400 500 4000 5700 5200 7400 900 450 1150 1600 Hair dryer, blower . type" ' ' Hair dryer, helmet type ' . ' . Permanent wave ma chine ' Neon sign, per linear ft of tube Steriliser, instrument Miscellaneous Electrical Appliances . M Fan, 165 w; Low, 915 w; ' High, 1580 w 1580 5400 M Fan, 80 w; Low, 300 w; - . 705 2400 High, 710 w M 60 heaters at 25 w 1500 5000 each, 36 in normal use M in. outside diam. $6 in. outside diam. - . For physicians; ther A mostat cuts off 550 1100 3750 w before boiling 2300 400 2700 1870 330 2200 850 150 1000 30 60 650 1200 30 60 .1850 Miscellaneous Gas-Banting Appliances ' Burners, laboratory Small Bunseq Small Bunsen Fishtail * Fishtail ' Large Bunsen Cigar lighter Hair dryer, 5 helmets Stoves, oven He in. Barrel Ut in. Barrel Mj in. Barrel >16 in. Barrel l)i in. Mouth M Manufactured Gas M Natural Gas M Manufactured Gas M Natural Gas M Adjustable orifice M Continuous Flame A Heater and fan blow ing air to helmets Insulated, modern . Not insulated l<` 1800 3000 3500 5500 6000 : 2500 33000 960 240 1200 1680 420 2100 1960 490 2450 3080 770 3850 3350 850 4200 900 100 1000 15000 4000 19000 25000 6000 .7200 1800 9000 25000 8500 9200 2300 11500 * For rNUartattppiiucM mallnii|i ei--trifl i>d gjiwdliBtoai id burning tppliumi. ' ' * When Umm eppli&nce* tie boodod nd prorided with adequate exhaust, use fiO percent a teontamended rate of beat tain troa uabooded applianeea. 202 CHAPTER 13 1959 Guide hi -- h ' the room load, ^ ^ . Use the equation ' hi -- k (Space sensible load + apace latent load) Wt -- lV, Space latent load/1076 * where h, " enthalpy of moist air supplied to the space, Btu per pound of dry air. hi -- enthalpy of moist air at room design conditions, Btu per pound of dry air. W, = humidity ratio of moist air supplied to the space, pounds of vapor per pound of dry air. W{ humidity ratio of moist air at room design conditions, pounds of vapor per pount of dry air. Note that the ratio (space latent load/1076) is the equivalent of the required rate of water vapor removal in pounds per hour. If the rate of water removed is known, it may be used directly in Equation 18. 3. Draw a line through the reference point on the ASHAE Pstchrometric Chart and the value of (hi -- h,)/(Wt -- W,) determined above. Draw a second line through the state'point of the room air (design wet-bulb and dry-bulb temperatures) parallel to this line. This is the condition line for the process. 4. Read the temperature where the condition line from step 3 intersects the saturation line. This is called the apparatus dew point. ' See Fig. 5. Note that instead of using this graphical method the left hand side of Equation 18 may be solved by trial and error by substituting values of h, and W. corresponding to assumed apparatus dew-point temperatures. 5. Compute the required air quantity from the relation ' heat load is relatively high, it is often necessary to circulate more air with a higher delivered dry-bulb temperature in order to produce a thermodynamic balance. If the dry-bulb temperature of the air supplied to the space is known, the required air quantity can be calculated from the formula, g Qr 1.08 (U - t.) (20) or the supply temperature L can be determined as follows. 1-08 X <2~ (21) EXAMPLE--COOLING-LOAD CALCULATION Example It: A one-story office building Fig. 6 is located in an eastern state near 40 deg latitude. The adjoining buildings on the north and west are not conditioned, and the air- tern- ft. - sensible / (l .08 [(SP*" ) - ( ApP""\l load / { |_\dry-bulb/ \dew-point /J X (1 - bypass)\. (19) \ factor /J The magnitude of Q,, is substantially the quantity, cfro, of cooled ana dehumidified air for which the distribution system must be designed. -- The numerical factor 1.08 is derived from the product 1 cfm X 60 min X 0.244 X 0.075^1 --= 1.08, assuming an average supply air dew point of 55 F. Since standard air density (0.075) includes the weight of the water vapor, it is desirable to reduce it to the basis of dry air by the last factor where 0.00923 " humidity ratio of air at 55 F dew point, and 0.62 -- ratio of density of water vapor to dry air at same tem perature and pressure. Refer to Chapter 23 for coil selection. Note that the product Kspace dry-bulb) -- (apparatus dew point}] X (1 -- coil bypass factor) is equal to the dry-bulb range through which the conditioned air is cooled. Hence, in rare instances when the condition line of the process may not intersect the saturation line, any other convenient reference temperature on the condition'line may be used instead, pro vided that the coil bypass factor is specified accordingly on the proper basis. . .. MINIMUM ENTERING AIR TEMPERATURE Due consideration must be given to the temperature of the tor entering the conditioned space in order to prevent ob jectionable drafts. With ceiling-type diffusers or wail grilles with a high aspect ratio (see Chapter 20), many engineers consider 20 deg as the maximum difference for good design under average conditions. This difference can only be exceeded with extremely high ceiling outlets or wall grilles. Thus, if 80 F dry-bulb is to be maintained in a space with average ceiling height, the minimum delivered air temperature would be limited to about GO F dry-bulb temperature. If the latent fig. 6____Plan of One-Story Office Building p^rature within them is known to be substantially equal to the outdoor air temperature at any time of the day. South wall construction: 8-in. concrete block, 4-in. brick veneer. (Table 7, Chapter 9, U TM 0.41.) East wall and outside north wall construction: 8-in. con crete block, no plaster on walls. (Table 6, Chapter 9, U = 0-52.) West wall and adjoining oorth party wall construction: . 13-in. solid brick, no plaster: -- or, V = 0.263. Use U = 0.26. U 1.65 5 1.65 Roof construction: 2M-o- A*t roof deck of 2-in. gypsum slab on K-in. asbestos cement-board surfaced with built-up roofing. (Table 13B, U -- 0.34 for tummer.) Floor construction: 4-in. concrete on ground. Window: 3 ft x 5 ft, nonopening type, with medium colored Venetian blinds for windows on south wall.* Approximately 4-in. reveal on all windows. ' Front doors: Two 2 ft-6 in. x 7 ft (glass panels). . . . Side doors: Two 2 ft-6 in. x 7 ft 0^ glass panels). -Rear doors: Two 2 ft-6 in- x 7 ft (wood panels). Outdoor design conditions: Maximum dry-bulb 95 F, wetbulb 78 F; W, *= 0-0168 lbs vapor per lb dry air; K --'41.38 Btu per lb dry air. Indoor design conditions: Dry-bulb 80 F, wet-bulb -65 F; Wi - 0.0098 lb vapor per lb dry air; hi - 29.95 Btu per lb dry air. . Occupancy: 85 office workers. Lights: 12,000 watts, fluorescent; 4000 watts, tungsten. Fan motor: 7M hp. Cooling Load 203 Assume that cooling coil has. a bypass factor, of 0.15, i.e., that 15 percent of the air passes through the coil without con tacting the coil surface. ' ' Conditioning equipment to be located in adjoining structure to north. Find: Total, sensible, and -latent maximum cooling loads and required air quantity through conditioning equipment. Solution: From Table 3, the recommended ventilation rate is 15 cfm per person. Total necessary -- 85 X 15 -- 1275 cfm or 76,500 cu ft per hr. As the room volume is 40,000 cu ft, the air changes per hour will be 76,500/40,000 -- 1.91 which is more than one air change. Estimated Time of Maximum Cooling Load: For this job, judgment indicates that the roof will make the greatest single contribution to the cooling load. Hence, the time of maximum cooling load probably will be the time of maximum heat gain through the roof. From Table 9 the maxi mum temperature differential for a 2-in. gypsum roof of me dium weight construction is 54 deg at 4:00 p.m., and 53 deg at 3:00.p.m. Examination of Table 12.(40 deg N Latitude) shows that solar heat gain through gfass'on the south wall is 18 Btu per (hr) (sq ft) at 4:00 p.m:, and'42 Btu at 3:00 p.m. This-indicates that the maximum cooling load occura at.ap proximately 3:00 p.m. Therefore make load calculations at 3:00 p.m. sun time. (This may be slightly different from 3:00 p.m! local time.) In some cases, there would be no clear-cut evidence of this nature, and consequently', it would be neces sary to estimate the load for several successive times, and then to select the maximum. Heat Gain Through Outer Wall and Roof Areas: From Table 10 the temperature differential for the south wall (8-in. concrete block with 4-in. brick veneer) may be about the same as a 12-in, brick which is 6 deg at 3:00 p.m. for a dark colored wall. From the same table, the temperature differential for the east wall (8-in. concrete block with plaster) will be 11 deg at 3:00 pjn.for a light colored wall (interpolating be tween 2:00 ana 4:00 p.m.). Likewise, tbe temperature differ ential for the north exposed wall (8-in. concrete block plus plaster) will be 3 deg at 3:00 p.m. (by interpolation) for a light wall. .. - The party wall of 13-in. brick on tbe west side and part of the north side may be treated as if it were an outside wall in the shade which has a temperature differential (from Table 10)* of 2 deg. ' For the door in north wall, estimate U -- 0.59 from Chapter 9. The outdoor temperature at 3:00 p.m. is 95 F. Neglect time lag and any decrement factor. The temperature differential is (t -- U) -- 95 -- 80 -- 15 deg. The tabulation of the preced ing values at 3:00 p.m. is given in the following table: B"TM" Nrr So Ft Twin . TOBB DirrtaZHTial F Dm ' Hsat Trans MtaaiOK CotmC1KNT . V Hkat ' Flow ' Rats m- Houi Bto Roof South wall East wall North exposed wall - West A north party wall Door in north wall. 4000 405* 765* 170* 1065* 35 53 6 11 3 2 15 0.34 0.41 0.52 0.52 0.26 0.59 72,000 995 4,380 265 550 310 78,500 * CaIctiUW from (ran wall aro*. lew window* mad doora. Heat Gain Through Glass Areas: . In computing the load for 3:00 p.m., only the south windows and doom will be exposed to direct sunlight. Tables 12 and 13 will give the total heat gun from the glass areas. Tbe window reveals will shade the south windows; the fraction of the window area receiving direct radiation is obtained from Equa tion 5 by substituting values as follows: n - s/l - 4/60; r* -- 4/36; 0 - 45.5 deg, tan 0 7 -- 74 deg, tan y -- 3.487, cos y -- 0.276 1.02 G, - 1 . ( * \ ( 4 \ (1.02)(3.487) + \60/ \36/ 0.276 " '462' The south doors will be considered entirely sunlit. The out door air temperature is 95 F at 3:00 p.m. From Table 25 tbe inside Venetian blind factor is 0.65. The instantaneous heat gains due to transmitted direct and diffuse solar radiation, and from convection and radiation gain, are found in Tables 12 and 13 as listed below for the south-facing doors and windows, the north-facing windows and the glass doors in the east wall. The gain through the solid portion of the east doors may be approximated by use of Fig. 3, since the wood panels have little heat capacity. From Table 4 the diffuse radiation value is taken as 18 Btu per (hr) (sq ft) from which t, + aJt/fa* is found to be 98.2 for a = 0.7 and /* - 4.0. From Fig. 3, q -- 22.0 Btu per (hr) (sq ft). These heat gains are itemized in the following table. * Location So Ft Frac tion Trans Sous Gam Btu/(hr) (m ft) Cow and Has Gain Btc/(hr) (sq ft) Total Gain Total Bto/ Gain () Btu/sr (sq ft) South windows* 60 0.462 13 South doors 35 1.00 42 East doors Glass 18 __ 14 Wood 18 __ -- North windows 30 -- 15 Total................ 19 32 1920 19 61 2135 17 31 560 22 22 395 17 32 960 5970 * Shade ass. - In some jobs it would be desirable to increase (or decrease) the instantaneous radiation beat gun by a load-lag factor. The reason for not doing so in this case is that the solar gain is of a low magnitude, and reference to the table indicates that 0.8 of the previous hour would not affect the results materially. Heat Gain from Ventilation and Infiltration: Since the desired outdoor air rate 1275 cfm is greater than one air change per hour, it will be satisfactory for determining tbe ventilation component of the heat gain. . Window infiltration can be taken as negligible since the windows do not open. Door infiltration requires some judgment. Assume that for . each person passing through the double doors, the infiltration will be 100 cu ft of outdoor air, see Chapter 10, Table 3. Assume that the outside doors will be used at the rate of 10 persons per hour and the inside doors at the rate of 30 persons per hour. Total infiltration will then be 40 X 100 -- 4000 cfh or 67 cfm. - .. Tbe design rate of entry of outdoor air is then: Q = 1275 + 67 - 1342 cfm. The sensible, latent, and total loads are determined from Equations 7, 8, and 9, respectively, at 3:00 p.m. (L -- 95, ti ~ 80, W, -- 0.0168, Wi -- 0.0098). All the air entering the room as infiltration becomes a part of the space load. . Infiltration (see Equations 7, 8, and 9): ' j. -- 67 X 1.08 (95 -- 80) -- 1085 Btuh, sensible. q. - 67 X 4840 (0.0168 - 0.0098) - 2270 Btuh, latent. qt " g. + q, - 1085 + 2300 - 3385 Btuh, total. ft 204 CHAPTER 13 1959 Guide Ventilation Air Taken through Cooling Unit Which Become* a Part of the Space Load (see Equation* 10 and 11): - gti 1275 X i.08 (85-80) (0.15) = 3,100 Blau, sensible. = 1275 X 4840 (0.0168-0.0098) (0.15) = 6,480 Btiih, latent. Ventilation Air Taken through Cooling Unit Which Doe* Not Become a Part of the Space Load (see Equatione 12 and 13): q,, - 1275 X 1.08 (95-80) (1-0.15) =* 17,600 Btub, sensible. q,, = 1275 X 4840 (0.0168-0.0098) (1-0.15) m, 36,715 Btub, latent. q, - << + + 9* + J - 3100 + 17,600 + 6480 + 36,715 - 63,895 Btuh total. Heat Gain from Source* within the Conditioned Space: For tbe occupants, use the data of Table 27 for moderately active office work. Sensible beat gain - 85. X 200 = 17,000 Btu per hr. Latent heat pun - 85 X 250 - 21,250 Btu per hr. ' . Total -- 38,250 Btu per hr. For the gain from lighting, use Equation 15 with a use factor of unity, and a special allowance factor of 1.20 for the fluorescentB and of unity for the tungsten globes. q,i a (12,000 X 1.20 + 4000) X 3.41 = 62,700 Btu per hr. For the fan motor, use Equation 16 with a load factor of unity, and omit term Motor Efficiency because the motor is not within the space. 9m - 7.5 X 2544 = 19,100 Btu per hr. Moisture Permeation, Miscellaneous Allowance, and the Load- Lag Estimate: -- Moisture permeation will be negligible, since this is a com fort job with a good building construction. There would oe some heat gain in the.ductwork, but this, would not be great because of the short run involved. Practical judgment for this job would suggest .that no adjustment for load lag need be made to the load as computed. (Refer to Fig. 4). While it is true that inside radiation forms an.impor tant part of the total heat gain, it is advisable to be conserva tive mrecognizing the effect of the large, flat, hot roof on the comfort sensations of the occupants. Radiation from the rela tively low ceiling, augmented by heat absorption from the lighting fixtures, would produce 's sensation of warmth in excess of the nominal effective temperature (see Chapter 6) established by the wet-bulb and dry-bulb temperatures. Hence, it is not desirable to take advantage of every small decrease possible in the peak design load, especially since the peak occurs in mid-afternoon when everything would be rather well warmed. ' , '' Total Loads and Required Air Quantity through Conditioning Equipment: ' . .- The total loads are summarised in the following table: ' . Summary or Total Loads--Example 11 Load Cokmwkr ' 8cksxblb Btu/kb L*rorr. Btu/s* Infiltration 67 cfm......................................... 78,500 5,970 1,085 3.100 17,000 62,700 19.100 187,455 17,600 2,270 6,480 21,250 30,000 36.715 66.715 271,770 Compute tbe enthalpy difference ratio from Equation 18. hi -- hi Wi-W, (187,455 + 30,120) X 1076 - 7770. 30,120 From the ASHAE Pstchrometric Chart, Chapter 3, de termine that the apparatus dew point is 53.9 F. Compute the effective air quantity (Equation 19).-Then, Qr ' 187,455 7830 cfm. 1.08(80 - 53.9) X 0.85 (Refer to Chapter 23 for coil selection.) From note under Equation 19 the dry-bulb range will be (80 - 53.9) X 0.85 - 22.2 deg, and the dry-bulb temperature of air leaving the coil will be 80 -- 22.2 TM 57.8 F. The drybulb temperature leaving the fan .(including the heat supplied by the fan motor) or, delivered into the room, will be (from Equation 21): . 187,455 - 19^00 80 -.19.9 60.1 F. 1.08 X 7830 With good distribution and diffusion, this' temperature should not produce objectionable drafts. - ' *. The, various calculations for the sensible, latent, and total heat loads for Example 11 may be summarized'as follows:. Example 11: Summary Outdoor Common.........4$ DB 8?acb Common...............60 DB 78 WB. 04168 Humidity Ratio 66 WB . 0.0066 Humidity Ratio . DOfKURCB....'...............16 _ 0.0070 . . Sensible Load ' ' ' Transmission ` . - ' Btu/Hr- Roof 4000 sq ft X 53 X 0.34 -.................. .. 72,000 8; wall 405 sq ft X 6 X 0.41 ..................... 995 E. wall 765 sq ft X 11 X 0.52 -................... 4,380 ' N. wall ex. 170 sq ft X 3a X 0.52 =.............. N. & W. party wall 1065 sq ft X 2 X 0.26 Floor none. . .. . Door 35 sq ft X 15 X 0.59 -........................... 310 All* glass and rest of doors =*................. ...... 3,020 Solar Radiation.'. ' ' . S. glass 60 sq ft'X 13 -............... ............... S. glass (doors) 35 sq ft X 42 "................. E. glass (doors) 18 sq ft X 14 "................. N. glass 30 sq ft X 15 -............................... '780 1,470 250 450 Internal Load Infiltration 67 cfm X 1.08 X 15 =............ Ventilation 1275 cfm X 1.08 X 15 X 0.15 . Lights (12,000 X 1.20 +'4000) 3.41 -......... People 85 X 200 - ..................... .................. Motor, fan 7.5 hp X 2544 "....................... . Total Sensible Space.Load.................. 1,085 3,100 62,700 17,000 19,100 187,455 'Latent-Load - ___ ' Infiltration 67,cfm X 4840 X 0.0071 --........ 2,270. Ventilation 1275cfm X 4840 X 0.0071 X 0.15.. 6,480 People 85 X 250 =......................... :.................. 21;250 - ' Total Latent Space Load. ....................... 30,000 Ventilation Air Which Does Not Become Part or Space Load . ' Sensible 1275 cfm X 1.08 X 15 X (1-0.15) -........... ..... 17,600 Latent 1275 cfm X 4840 X 0.0071 X (1-0.15) =............... 36,715 Grand Total Load..................................................... ` 271,770 Cooling Load LETTER SYMBOLS USED IN CHAPTER 13 a = fraction of incident solar radiation absorbed, dimen sionless; subscripts D, d, and t refer to direct, diffuse, and total, respectively: 0 solar altitude, degrees. y -- wall solar asimutb, degrees. " emissivity, dimensionless. 9 " incident angle, degrees. r = fraction of incident solar radiation transmitted, dimen sionless. , Subscripts D, d, and t refer to direct, diffuse, and total, respectively. 4 -- solar azimuth, degrees, if- " wall azimuth, degrees. A " area across which heat is being transferred, square feet. 5 ** fraction of air pa/wing through coil which does not con ' tact surfaces, coil bypass factor. f = unit surface conductance, Btu per (hour) (square foot) (Fahrenheit degree). Subscripts c, r, o, and i refer to convection, radiation, outdoor, and indoor, respectively. Gf = fraction of total window area receiving direct solar radiation when shaded by window reveal, dimensionless. h -- enthalpy .of air per pound of dry air, Btu per pound. Subscripts i, o, and s refer to indoor, outdoor, and sup ply air, respectively. I -- incident solar radiation, Btu per (hour) (square foot). Subscripts D, d, Dn, and t refer to direct, diffuse, direct normal, and total solar radiation, respectively. K " cosine of angle of incidence for direct solar radiation -striking a surface, dimensionless. k -- thermal conductivity of building material, Btu per (square foot) (hour) (Fahrenheit degree per inch). .. l -- height of window, feet. M ~ the permeance of the specimen in perms or grains per (square foot) (hour) (inch, of mercury vapor pressure difference). Q -- rate of entry of outdoor air, cubic feet per minute. Qr " required air quantity through conditioning equipment, - cubic feet per minute. q -- instantaneous rate of heat transfer, Btu per hour. q, = instantaneous latent heat load, Btu per hour. qH -- Instantaneous space latent ventilation load, Btu per hour. . q,, == instantaneous latent ventilation load which does not become a part of space load, Btu. qm = latent heat load due to moisture transmission through materials, Btu per (hour) (square foot). q, *= instantaneous sensible heat load, Btu per hour. 9w = instantaneous space sensible ventilation load, Btu per hour. q,, = instantaneous sensible ventilation load which does not become a part of space load, Btu per hour. 9 " 9. + 9*, also 9,,- + q,, + qti + q,t, Btu per hour. R = low temperature.radiant energy received from outdoor . surrouxrainp (does not include'BoIar radiation), Btu per . (hour) (square foot of receiving surface). 205 R = radiant energy emitted by a black body, Btu per (hour) (square foot). Subscripts go and L refer to outdoor sur faces of glass and building, respectively. S = rate of heat storage within a glass section, Btu per (hour) (square foot). t, *= sol-air temperature, Fahrenheit. t,i TM temperature of indoor glass surface, Fahrenheit. t,. - temperature of outdoor glass surface, Fahrenheit. tt = indoor air temperature, Fahrenheit. lm -- 24-hr cyclic average sol-air temperature, Fahrenheit. 11 = outdoor air temperature, Fahrenheit. . t, - room supply air dry-bulb temperature, Fahrenheit. U -- overall coefficient of heat transfer of a structural sec tion, Btu per (square foot) (hour) (Fahrenheit degree). v, -- volume of outdoor air per pound of dry air, cubic feet. w = width of window, feet. W " humidity ratio, pounds moisture per pound of dry air. Subscripts t, o, and refer to indoor, outdoor, and sup ply air, respectively. REFERENCES 1 Application Engineering Standards for Air Conditioning for Comfort (Air Conditioning and Refrigerating Machinery Association, Inc., 1947, p. 4). . * W. V. Consol&zio and L. J. Pecora: Minimal replenish ment air required for living spaces (ASHVE Transactions, Vol. 53, 1947, p. 127). . . * Recommended Safe Practice of the NBFU for Hospital Operating Rooms (National Board of Fire Underwriters Pamphlet No. 56). * P. Moon: Proposed standard solar radiation curves for engineering use (Journal of the Franklin Institute, Vol. 230, November 1940, p. 5). * C. O. Mackey: ASHVE Research Report No. 1268-- Summer weather data and sol-air temperature--Study of data for Lincoln, Nebr. (ASHVE Transactions, Vol. 51, 1945, P- 93). * C. O..Mackey and E. B. Watson: Summer weather data and sol-air temperature--Study of data for New York City (ASHVE Transactions, Vol. 51, 1945, p. 75). 1 G. A. Hendrikson and J. H. Walker: Summer cooling for comfort as affected by solar radiation (Heating and Ventilating, Vol. 29, November 1932, p. 14). I Tables of Computed Altitude and Azimuth (U. S. Navy Dept. Hydrographic Office Bulletin No. 214, Vol. 1-9, 1940). * The American Nautical Almanac (U. S. Naval Observatory, annual). . F. C. Houghten, J. L. Blackshaw, E. M. Pugh, and Paul McDermott: ASHVE Research Report No. 923--Heat trans mission as influenced by heat capacity and solar radiation (ASHVE Transactions, Vol. 38, 1932. p. 231). J. S. Alford, J. E. Ryan, and F. O. Urban: Effect of heat storage and varia tion in outdoor temperature and solar intensity on heat trans fer through walls (ASHVE Transactions, Vol. 45, 1939, p. 369). -Victor Paschkis: Periodic heat flow in building walls determined by electrical analogy method (ASHVE Trans actions, Vol. 48, 1942, p. 75). C. O. Mackey and L. T. Wright, Jr.: Periodic heat flow--Homogeneous walls or roofs (ASHVE Transactions, Vol. 50, 1944, p. 293). C. O. Mackey and L. T. Wright, Jr.: Periodic heat now--Composite walls or roofs (ASHVE Transactions, Vol. 52, 1946, p. 283). H.' A. Johnson: Periodic heat transfer at the inner surface of a homogeneous wall (ASHVE Transactions, Vol. 54, 1948, p. 143). u F. C. Houghten, Carl Gutberlet, and A. A. Rosenburg: The effect of solar radiation on the heat transmission through walls (American Society of Testing Materials Symposium on Thermal Insulating Materials, 1939). II F. C. Houghten,H. T. Olson, and Carl Gutberlet: ASHVE Research Report No. 1157--Summer cooling load as affected / Jig 206 CHAPTER 13 1959 Guide by beat gain through dry, sprinkled and water covered roofs (ASHVE Transactions, Vd. 46, 1940, p. 237). 11 F. C. Houghten, Carl Gutberlet, and A. J. Wahl: ASHVE Research Report No. 1002--Cooling requirements of single rooms in a modern office building (ASHVE Transactions, Vol. 41, 1935, p. 53). 14 J. N. Livermore: Study of actual vs. predicted coding load on an air conditioning system (ASHVE Transactions, Vol. 49, 1943, p. 287). 11 F. C. Houghten, E. C. Hach, S. I. Taimuty, and Carl Gutberlet: ASHVE Research Report No. 1195--Heat gain through walls and roofs as affected by solar radiation (ASHVE Transactions, Vol. 48,1942, p. 91). 11 J. P. Stewart: Solar heat gain through walls and roofs for cooling load calculations (ASHVE Transactions, Vd. 54, 1948, p7361). . ____ 17 G. V. Parmelee and W. W. Aubele: ASHVE Research Report No. 1442--Radiant energy emission of atmosphere and ground (ASHVE Transactions, Vol. 58, 1952, p. 85). 11 D. Brunt: Radiation in the atmosphere {Supplement to the Quarterly Journal of the Royal Meteorological Society, Vd. 66,1940). .. UG. V. Parmelee, W. W. Aubele, and R. G. Huebscher: ASHVE Research Report No. 1333--Measurements of solar heat transmission through flat glass (ASHVE Transactions, Vd. 64, 1948, pi 165). ** G. V. Parmelee and W. W. Aubele: ASHVE Research Report No. 1348--Solar and total heat gain through double flat glass (ASHVE Transactions, Vol. 54, 1948, p. 407). n G. V. Parmelee and W. W. Aubele: ASHVE Research Report No. 1374--Solar energy transmittance of eight-inch hollow glass block (ASHVE Transactions, Vol. 55, 1949, p. 435). G. V. Parmelee and W. W. Aubele: ASHVE Research Report No. 1399--Heat flow through unshaded glass: Design data for use in load calculations (ASHVE Transactions, Vol. 56, 1950, p. 371). **G. V. Parmelee and W. W. Aubele: ASHVE Research Report No. 1417--Solar energy transmittance of figured rolled glass (ASHVE Transactions, Vol. 57, 1951, p. 209). ** D. J. Vild and G. V. Parmelee: ASHAE Research Re port No. 1560--Heat gain through glass skylight fenestrations (ASHAE Transactions, Vol. 62, 1956, p. 89). 11 G. V. Parmelee and D. J. Vild: ASHVE Research Re port No. 1485--Design data for slat-type sun shades for use in load estimating (ASHVE Transactions, Vol. 59, p. 403). G. V. Parmelee, W. W. Aubele, and D. J. Vild: ASHvE Re search Report No. 1474--The shading of sunlit gtass: An experimental study of slat-type sun shades (ASHVE Trans actions, Vol. 59, 1953, p. 221). G. V. Parmelee and W. W. Aubele: ASHVE Research Report No. 1460--The shading of sunlit glass: An analysis of the effect of uniformly spaced flat opaque slats (ASHVfi Transactions, Vol. 58,1952, p. 337). C. S. Leopold: The mechanism of heat transfer, panel cooling, heat storage (Refrigerating Engineering, July 1947, p. 33). C. S. Leopold: Hydraulic analogue for the solution of problems of thermal storage, radiation, convection and con duction (ASHVE Transactions, Vol. 54, 1948, p. 389). B C. O. Mackey and N. R. Gay: Heat gains are not cooling loads (ASHVE Transactions, Vol. 55, 1949, p. 413). " C. O. Mackey and N. R. Gay: Cooling load from sunlit glass (ASHVE Transactions, Vol. 58, 1952, p. 321). ** See Reference 1, p. 8. ** C. M. Ashley: Psychrometric factors in the air conditioning estimate (ASHVE Transactions, Vol. 55,1949, p. 91). * W. G. Darley: Cooler footeandles for air conditioning (ASHVE Transactions. Vol. 46, 1940, p. 367). 1ES-ASHVE Joint Committee on Lighting and Air Conditioning: Lighting and air conditioning design factors (ASHVE Journal Section, Beating, Piping and Air Conditioning, September 1941, p. 605). H. M. Sharp: Lighting and air conditioning (Heating and Ventilating, November 1942, p. 35). " Compiled by J. P. Stewart from various sources. CHAPTER 14 RADIATORS, CONVECTORS, BASEBOARD AND FINNED-TUBE UNITS Definitions, Heat Emission, Roctiafors, Convectors, Baseboard, Finned- Tube, Ratings, Corrections for Non-Standard Conditions, Enclosed Radiators . ADIATORS, convectors, baseboard, and finned-tube I and 2 are included to provide principal dimensions and R, are the types of heat-distributing units used in steam average ratings. and hot water heating systems to supply heat to a room by The small-tube type radiators, with a spacing of Wa in. radiation and convection. The function of these devices is per section, occupy less space than the older column and the maintenance of the desired mean radiant and air tem large-tube radiators, and are particularly suited for instal peratures in the area. Since heat losses through the various lation in recesses. parts of the structure constantly tend to lower these tem After a study of the demand for various sizes of radiators, peratures, heat distributing units should be so placed and the Institute of Boiler and Radiator Manufacturers, in co regulated that their output will replace the losses when and operation with the Division of Simplified Practice, National where they occur. If 80 percent of the room heat loss occurs Bureau of Standards, established Simplified Practice Recom through a cold wall or window area, then 80 percent of the mendation R174-47, Cast Iron Radiators, for small-tube input should be introduced in or directed toward that area. cast-iron radiators. Table 3 shows the size and dimensions The term radiator is generally confined to sectional cast- now being manufactured. iron radiation. Cast-iron radiator types may ..be column, Wall radiators are hung from wall brackets and are well large-tube, small-tube, or wall. adapted to use in factory buildings. Teste have shown that The term convector refers to a heat-distributing unit that the heat emitted from a wall-type radiator may be reduced operates with gravity-recirculated room air, is surrounded from 5 to 10 percent if the radiator is placed near the ceil on all sides by an enclosure having an air-inlet opening below ing with the bars horizontal and in an air temperature ex the heating element, and an air-outlet opening above-the ceeding 70 F. Installation of wall radiators at the ceiling is heating element. . not recommended because the resulting large temperature The terms baseboard and baseboard radiation refer to gradients between floor and ceiling make it difficult to heat steam or water beat-distributing units designed for installa the living zone satisfactorily. Dimensions and heat emission tion along the bottom of the walls replacing the conven rates of wall radiators for normal wall installations are tional baseboard. They operate with gravity-recirculated given in Table 4. . room air, and have a substantial portion of their frontal face surface directly exposed to the room. Pipe Coils The term finned-tube refers to steam or water heat-dis tributing units fabricated from metallic tubing with metallic fins bonded to the tube. They operate with gravity-recircu lated room air and are designed for installation without enclosure, or with open-type grilles or covers, or with en closures having top, front, or inclined outlets. Pipe coils are sometimes used in factory buildings and are usually placed under windows or along heavily-exposed walls. The heat emission of such pipe coils may be obtained from Table 5. CONVECTORS HEAT EMISSION Steam or water heat-distributing units emit heat by radia tion and convection. These heat-transfer processes and the factors that affect them are discussed in detail in Chapter 5. In general, those unite having a large portion of their heated surface exposed emit a larger portion of heat by radiation than do units having their heating surfaces com pletely or partly concealed from view. The output of a heat-distributing unit is expressed in units of Btu per hr (Btuh), 1000 Btu per hr (Mbh), or in square feet equivalent direct radiation (EDR) (eg., 240 Btuh for steam = 1 sq ft EDR). RADIATORS Column and large-tube radiators are no longer manufac tured, but since many of these units are still in use. Tables Convectors are made in a wide variety of depths, sizes, lengths, and enclosure or cabinet types. The basic sizes and types are listed in Simplified Practice Recommendation 238-50, Convectors. The heating elements are available in fabricated ferrous and non-ferrous metals as well as cast iron. The air enters the enclosure below the heating element, is heated in passing through the element, and leaves the en closure through the outlet grille located above the heating element. Factory-assembled units comprised of a heating element and enclosure are widely used; These may be free standing, wall hung, or recessed, (Fig. 1) and may have outlet grilles and arched inlets or inlet grilles as desired. In cases where cabinets or enclosures are to be used but are not furnished by the manufacturer, it is important that the proportions of the cabinets or enclosures and the grilles be so designed that they will not impair the performance of the assembled convector. It is desirable that the cabinet or 207 208 CHAPTER 14 1959 Guide Table 1 .... Column-Type Cast-Iron Radiator Acceptra* Baling per Section* Height In. Ora Cobra Sqfl Btuh 16 IS 20 1H 360 22 23 m 400 28 2 480 32 2H 600 38 3 720 45 Twp Cofanan Sq Ft Stab 1M 2 2* 2* 2H. 3* 4 5 360 480 540 560 640 800 960 1200 Three Column Sq Ft Btuh 2K 540 3 720 3H 900 4K 1080 5 1200 6 1440 Four Cofamn Rre Cotuma Six Cobra Sq Ft Btuh Sq Ft Btuh SqFt Btch 13 16 18 20 22 26 32 . 38 45 3 720 4 5 6* 8 10 960 1200 - 1560 1920 2400 7 10 1120 1680 2400 3 3H 4H 5. 720 900 1080 1200 * These ration on baaed on steam at 315 F mod air at 70 F. They apply only to installed cadsatose ezpoaed in a nermsi manner; not to radiatoo toatalled IftiinH enelneinee pjlla, OX nndet ahelvea. For Btq MT hOW ntlD|> at Other temperatures, divide table vafaee by factor* found in Table 7. ' enclosure for the convector fit as snugly as possible so that the air phasing through cannot bypass the heating element. BASEBOARD UNITS Baseboard heat-distributing units are divided into three types: (1) radiant, (2) radiant-convector, and (3) finned- tube.1 . Radiant-type baseboard is made of cast iron or steel. This type of unit emits a large portion of its heat output by radia tion. Units are sometimes suspended from the ceiling in rooms having little or no available wall space for floor mounted units. As the convected heat obtained from these units when mounted at the ceiling is less than when they are mounted at floor level additional length must be added as recommended by the manufacturer to allow for the reduc tion. Radiant-convector type baseboard also is made of cast iron or steel. The units are provided with air openings at the top and bottom to permit circulation of room air over the wall side of the unit. The wall side of the unit has ex tended surface to provide increased heat output. A large portion of the heat emitted is transferred by convection. Hus type of baseboard having a greater output per linear foot than the radiant type is particularly adaptable where wall space is at a premium or the beat loss of the room is high. ` finned-tube type of baseboard has a finned-tube heating element that is concealed by a long low sheet-metal enclo- Toble 2 .... Large-Tube Cast-Iron Radiators Sectioned, cosf-ireo, fufaufor-type radiofan of the large-tube partem, that h, haring tabes approximately 1)4 in. in dmnefer, 2)4 in. en craters. Number of Tabes Catalog Bating Height per Section* Width Secttoa t*g Center Height* to Spacing . Tapping Sq Ft Btuh In. In. In. In. m 420 20 2 480 23 3 2* 560 28 3 720 32 3* 840 38 2* 4* 2H 4* 2* 4* 2* 4* 2h 4* V*. 540 20 2% 600 23 4 2H 660 26 3>s 840 32 4* 1020 38 2* 4* 2H 4H 2* 4M 2* 4* 2H 640 20 3 720 23 5 3* 840 26 4* 1040 32 5 1200 38 8-W 2*<* 2*<* 2*< 2Hd . 2*<* 4* 4* 4)4 4* 4)4 3 720 20 3* 840 23 6 4 960 26 5 1200 32 6 1440 38 9-im 2* 4* 2* 4)4 2* 4)4 2* 2* 4)4 2X 600 14 2H 3 7 3 720 17 UH-WXs 214 3 m 880 20 2H 3 or 4* * Them ratios* tw based an sieas at 315 F aad air at TO :They apply only to htttelled radiator* ezpoaed in a normal manner; not to radiator* installed bohind enclosures, grilles, or under shelves. For Btu per hour ratings at other tern(matures, divide table values by (actor* found in Table 7. b MovimiiTw assembly GO eeetiona. Length equals number of ratioas times 3H in. .. * Where greater than standard leg heights are required, this dimension shall be G in., except for 7-tube sections, in heights from 13 to 30 in., inclusive, for which tola dimension shall be t<A in. Radiator* may be furnished without legs. 4 For 5-tube hospital-type radiation, this dimension is 3 in. sure or cover. A major portion of the heat is transferred to the room by convection. The output varies over a wide range depending on the physical dimensions and the materials used. When selecting this type of baseboard the designer should avoid using a unit with too high an output per linear foot. Baseboard performs best when units are so selected that they are installed along as much of the exposed wall as possible. - -. Hie basic advantage of the baseboard heat-distributing unit is that its normal placement is along the cold walls and under areas where the greatest heat loss occurs. Other advantages claimed for the baseboard heat-distributing unit are: it is inconspicuous; it offers a minimum of interference with furniture placement; and it distributes the heat near the floor. This last characteristic reduces the floor-to-ceiling temperature gradient to about 2 to 4 F deg, and tends to produce uniform temperatures throughout the room. It also makes baseboard heat-distributing units adaptable to base mentless homes, where cold floors are prevalent.* Radiators, Convectors, Baseboard and Finned-Tube Units 209 Table 3 .... Small-Tube Cast-Iron Radiators Heat loss calculations for baseboard heating systems are the same as those used for other types of heat-distributing units. The procedure for designing baseboard heating sys tems is given in / = B = R Installation Guide No. 5.* Rat ings for baseboard heat-distributing units' are expressed in Btuh per linear foot. RNNED-TUBE UNITS A finned-tube heat-distributing unit is a room-air beater composed of a finned-tube element fabricated from metjdKe tube to whicb metallic fins have been bonded. It does not include a fin-tube type baseboard dement provided with an enclosure for replacement of. the conventional baseboard. The finned-tube unit can be used with either steam or hot water systems. It has advantages for in<rtAl|af,inn where it is desired to distribute the heat along the entire outside wail and thereby prevent down drafts along the walls in buildings such as schools, churches, hospitals, and factories. Normal placement of finned tube is along the walls where the heat loss is greatest. If necessary, the units can be in stalled in two or three tiers along available wall space to meet the heating requirements. For hot water system instal- Table 4 .... Cast-iron Wall Radiators Approximate Dimensions--fnche* Heat Output4 Height Length or Width TMdnen Sq Ft Btuh 13* . 13* 22 13* 29 16* 22 13* 29 13* 3 3 3 .3 3 6* \ 8 8 11 11 1560 1920 1920 2640 2640 lations where two or three tiers are required, a sinuous water flow through the heaters is recommended because a header connection with parallel flow may permit the water to short circuit along the path of least resistance. * These rating* are based on (team i 115 P and air at 79 F. They apply only to installed radiators exposed to a norma] manner, not to radiators be hind enclosures, grilles, or uader shelves. Far Bta per hour ratings at other tem peratures divide table values by factors found in Table 7. Protection of the heating element may be provided by open-type grilles fabricated of expanded metal or perforated materials covering the top and front of the finned-tube element. Covers and enclosures are ft]an available to enhnniv* the appearance and to increase heating efficiency. * Table 5 .... Heat Emission of Pipe Coils Placed Vertically A cover is a fabricated shield haying at least a portion on a Wall (Pipes Horizontal) Containing Steam at of the front skirt made of solid material. It can be mounted 215 F and Surrounded with Air at 70 F Btv per linear foot of coil per how (nof linear foot of pipe) on the finned-tube dement so that there is clearance be tween the wall and the cover, and the rear of the finned-tube element is not completely enclosed. A cover may have a top, Size of Fipe 1 In. Hi In. min. front, or inclined outlet. An enclosure is a shield of solid material installed so that Single row..................... 132 162 Two................................ 252 312 Four................................ 440 545 Six................................... 567 702 Eight.............................. 651 796 Ten.................... 732 . 907 Twelve................. 812 1005 185 348 616 793 907 1020 1135 the finned-tube element is completely enclosed at both front and rear. An enclosure may have an integral hack or may be installed tightly against the wall so that the wall itself forms the back. An enclosure may have a top, front, or inclined outlet. ' Finned-tube units are available in four tube sizes from 1 in. to 2 in. IPS with various fin arrangements. The resis tance to the flow of water or steam is rather low so that a fe~ 210 CHAPTER 14 1959 Guide separate system of distribution piping is generally not re quired. The heating capacity of finned tube varies over a wide range depending on tube size, fin size and thickness, spacing of fins, and the materials used. A major portion of the heat transferred to the room to be heated is by convection. The capacity of finned-tube heat-distributing units is determined by test. The Institute of Boiler and Radiator Manufacturers has developed a testing and rating code for finned-tube type of radiation* Heat loss' calculations for finned-tube heating systems are the same as those used for other types of radiation. Ratings are expressed in Btuh per linear foot or square feet Equiva lent Direct Radiation per linear foot for steam, and Btuh per linear foot for water. RATINGS OF HEAT-DISTRIBUTING UNITS Radiators A standard method of testing radiators was adopted by the ASHAE in 1927/ This Code was withdrawn but the method is still used in industry. It provides for a standard test room, the temperature of which is to be maintained at 70 F, measured in the center of the room at an elevation of 5 ft above the floor. The steam temperature in the radiator is to be 215 F, which corresponds to 15.6 psia. The weight of condensate per hour, under these standard conditions, mul tiplied by the difference in the enthalpy of the steam enter ing the radiator and that of the condensate leaving the radiator, gives the radiator output in Btu per hour (Btuh). If the rating in square feet Equivalent Direct Radiation is desired, divide this output by 240 (which by definition is the Btuh equivalent of 1 sq ft EDR). Correction of output from non-standard test conditions to output at 70 F room and 215 F steam may be made by multiplying the output under test by the ratio (Standard temperature difference, steam -- air)1-* (Test temperature difference, steam -- air)1-* Convectors The generally accepted method of testing and rating both ferrous and non-ferrous convectors, is given in Commercial Standard CS140-47, Testing and Rating Convectors,* which has been developed cooperatively by the Convector Manu facturers Association, the Institute of Boiler and Radiator Manufacturers, other members of the trade, and. the 'Na tional Bureau of Standards. This Commercial Standard con tains details covering construction and instrumentation of the test booth or room and procedures for determining both steam and water ratings. Steam ratings are expressed in square feet EDR and Btu per hour (Btuh). Water ratings are expressed in Btuh at specified water temperature drops and average water tem peratures. Under the provisions of Commercial Standard CS140--47 the rating of a top outlet convector is established at a value not in excess of the test capacity (which is the heat ex tracted from the steam or water in the convector under standard test conditions). For convectors with other types of enclosures or cabinets a percentage that varies up to a maxi mum of 15 percent depending on the height and type of enclosure or cabinet is added for heating effect/17 The addilions made for heating effect must be shown in the manu facturer's literature. Table 6 .... Factors to Convert 1 = B=R Finned-Tube Steam Ratings to Hot Water Ratings at Temperatures Indicated Average Radiator Tampershire Factor Radiator Temperature 150 0.45 190 0.78 155 0.49 195 0.82 160 0.53 200 0.86 165 0-57 205 0.91 170 0.61 210 0.95 175 0.65 . 215 1.00 180 0.69 220 1.05 185 0.73 Baseboard The generally accepted method of testing and rating base boards is covered in the / = B -- R Testing and Rating Code for Baseboard Type of Radiation/ This Code contains details covering construction and instrumentation of the test booth, or room, procedures for determining steam ratings, and licensing provisions for the obtaining of approval of these ratings. Baseboard ratings include an allowance for heating effect of 15 percent, added to the test capacity. The addition made for heating effect must be shown in the manufacturer's literature. . Steam ratings are expressed in Btuh per linear foot or square feet EDR per linear foot. Water ratings are deter mined from steam ratings and are expressed in Btuh per linear foot, at specified water flow rates and average water temperatures. Finnfed-Tube The generally accepted method of testing and rating finned-tube heat-distributing units is covered in the / = B = R Testing and Rating Code for Finned-Tube Type of Radiation.* This Code contains details corering construction and instrumentation of the test booth or room, procedures for determining steam and water ratings, and licensing pro visions for the obtaining of these ratings. Steam ratings are expressed in Btub per linear foot or square feet EDR per linear foot. Water ratings are determined from steam ratings and are expressed in Btuh per linear foot at specified water flow rates and average water temperatures. The rating of a finned-tube unit in an enclosure having a top outlet is established at a value not in excess of the test capacity (which is the heat extracted from the steam or water in the unit under standard test conditions). For finned-tube with other types of enclosures or covers a per centage is added for heating effect which varies up to a maximum of 15 percent depending on the height and type of enclosure or cover. The additions made for heating effect must be shown in the manufacturer's literature. Corrections for Non-Standard Conditions The heat output of a radiator, convector, baseboard or finned-tube heat-distributing unit is an exponential function of the temperature difference between the air in the room Radiators, Convectors, Baseboard and Finned-Tube Units 211 Table 7 .... Correction Factors for Direct Cast-Iron Radiators and Convectors* Steam Freer. (Approx.) Heating Abs Steam or Vacuum Water In. Hg Sq In. 80 Room Temperature F 75 70 65 60 55 50 22.4 20.3 17.7 14.6 10.9 6.5 Lb per $q In. 1 6 15 27 52 3.7 4.7 6.0 7.5 9.3 11.5 15.6 21 30 42 67 150 160 170 180 190 200 215 230 250 270 300 2.58 2.17 1.8C 1.62 .1.44 1.28 2.36 2.(X 1.73 1.52 1.35 1.21 2.17 1.86 1.62 1.44 1.28 1.15 2.00 1.73 1.52 1.35 1 21 1.10 1.86 1.62 1.44 1.28 1.15 1.05 1.73 1.52 1.35 1.21 1.1C 1.00 1.62 1.44 1.28 1.15 1.05 0.96 1.10 1.05 1.00 0.96 0.92 0 88 0.85 o.oe 0.92 0.88 0.85 081 0.78 0.76 0.81 0.78 0.76 0.73 0.70 0.68 0.66 0.71 0.68 0.6b 0.64 0.62 0.60 0.58 0.58 0.57 0.55 0.53 0.52 0.51 0.49 Steam Prats. Heafmg Go,,. Abt Vacuum Lb per In. Hg Sq In. Temp. F Water 80 Inlet Air Temperature F 75 70 65 60 55 50 22.4 3.7 150 3.14 2.83 2.57 2.35 2.15 r.98 1.84 20.3 4.7 160 2.57 2.35 2.15 1.98 1.84 1.71 1.59 17.7 6.0 170 2.15 1.98 1.84 1.71 1.59 1.49 1.40 14.6 7.5 180 1.84 1.71 1.59 1 49 1.40 1.32 1.24 10.9 9.3 190 1.59 1.49 1.40 1.32 1.24 1.17 1.11 '6.5 11.5 200 1.40 1.32 1.24 1.17 1.11 1.05 1.00 1 h ner Sq In. 1 15.6 215 1.17 1.11 1.05 1.00 0.-95 0.91 6.87 6 21 230 1.00 0.95 0.91 0.87 0.83 0.79 0.76 15 30 250 0.83 0.79 0.76 0.73 0.70 0.68 0.65 27 42 270 0.70 0.68 0.66 0 63 0.60 0.58 0.56 52 67 300 0.56 0.54 0.53 0.51 0.49 0.48 0.47 * To determine the eise ai radiator or * ooorector {or a given apace, multiply the heat loes et the t^n in Bto per hour by the proper factor from the above table and select radiator or convector having an equivalent Btu per hour rating. An alternate method is to divide the beat loes in Btu per hour by 140 end multiply the rmult by the proper factor from the above table and select radiator or convector having an equivalent square loot rating. Todeterminethe heatingcapacity of a radiatorora convector under conditions other than the basic ones with the heating medium at a temperature of SIS F, and the room temperature at 70 F in the caee of a radiator, and the inlet air tern- me at S5 F in the ease of a convector, divide the beating capacity at the rating conditions by the proper factor from the above table. and the heating medium in the room-heating unit, or, ex pressed as an equation H = cit. - & (1) where H = beat output, Btu per hour (Btuh). c = a constant determined by test from Equation 1. t, = average temperature of heating medium, Fahrenheit. For hot water the arithmetical average of the entering and leaving water temperatures is used, i* " room air temperature, Fahrenheit. Air temperature 60 in. above the floor is generally used for radiators while the entering air temperature is used for all other types of heating units. n =* an exponent which equals 1 -3 for cast-iron radiators, 1.4 for baseboard radiation, and 1.5 for convectors. For finned-tube units n varies with both air and heat- Table 8 .... Correction Factors for Finned-Tube and Baseboard Radiation* Steam Pressure Heating Medium Cage Ab* Steam or lb per Water In. Hg Sq In. eo Inlet Air Temperature F 75 70 65 60 55 50 22.4 3.7 150 2.80 2.50 2.20 1.95 1.81 1.67 1.54 20.3 4.7 160 2.34 2.14 1.94 1.75 1.62 1.5(1 1.37 17.7 6.0 170 2.01 1.86 1.7C 1.56 1.46 i.3b 1.26 14.6 7.5 180 1.76 1.65 1.53 1.42 1.32 1.24 1.15 10.9 9.3 190 1.53 1 45 1.36 1-28 1.20 1.12 1.03 6.5 11.5 200 1.38 1.31 1.24 1.16 1.09 1.02 0.95 lb per Sq In. 1 15.6 215 1.17 1.12 1.06 1-00 0.95 0.90 0.85 6 21 230 i on 0.97 0.93 0.90 0.86 0.82 0.78 15 30 250 0 88 0.85 0.82 0.78 0.75 0.71 0.67 27 42 270 0.75 0.73 0.7C 0.6! 0.65 0.62 0.59 52 67 300 0.62 0.60 0.58 0.56 0.54 0.52 0.50 Steam Pressure Gage Abs Vacuum In. Hg Sq In. Heating Medium Temp. F Steam or Water 80 Inlet Air Temperature F 75 70 65 60 55 50 22.4 20.3 17.7 14.6 10.9 6.5 Lb per Sq In. 1 6 15 27 52 3.7 4.7 6.0 7.5 9.3 11.5 15.6 21 30 42 07 150 2.86 2.61 2.38 2.20 2.03 1.89 1.76 160 2.38 2.2C 2.02 1.89 1.7C 1.64 1.56 170 2.03 1.89 1.7( 1.64 1.54 1.44 1.38 180 1.76 1.64 1.55 1.44 1.38 1.21 1.23 190 1.54 1.44 1.37 1.2f 1.22 1.1b 1.09 200 1.38 1.29 1.23 1.16 1.09 1.05 1.00 215 1.16 1.10 1 05 1.00 0.95 0.92 0.88 230 1.0C 0 96 0.92 0.88 0.84 0.81 0.77 250 0.86 0.82 0.79 0.76 0.72 U.Vl 0.68 270 0.78 0.7C 0.68 0.6t 0.62 0.61 0-59 300 0.58 0.67 0.55 0.53 0.52 0.51 0.49 * To determine the heating opacity under condition, other then the besic ones with the heating medium at a temperature oI SIS F, and the inlet air tem perature at 65 F, divide the heating capacity at the besic rating conditions by the proper factor from the above table. ing medium temperatures. Correction factors to con vert outputs at standard rating conditions to outputs at other conditions are given in Tables 6, 7, and 8. Enclosure, Paint, Humidity Effect The general effect of an enclosure placed about a direct radiator is to restrict the air flow, and diminish the propor tion of output due to radiation. Enclosures of proper design may, however, improve the heat distribution within the room as compared to the heat distribution obtained with an unenclosed radiator/* * For a radiator or cast-iron baseboard the finish coat of paint affects the heat output. Oil paints of any color will give about the same results as unpainted black or rusty surfaces, but an aluminum or a bronze paint will reduce the heat emitted by radiation. The net effect may be a re duction of 10 percent or more in the total heat output of the radiator/** " " Same'commercial enclosures and shields for use on direct radiators are equipped with water pans for the purpose of 212 CHAPTER 14 1959 Guide adding moisture to the air in the room. Tests1* show that an average evaporative rate of about 0-235 lb per (hr) (sn ' ft of water surface) may be obtained from such pans, when a radiator is steam heated and the relative humidity in the room is between 25 and 40 percent. This source of supply of moisture alone is not adequate to maintain a relative humidity above 25 percent on a zero day. ; REFERENCES . ll -- B -- R Baseboard Heating Systems Installation Guide No. 5 (Institute'of Boiler and Radiator Manufacturers, 1953, 2nd ed.). ' `A. P. Krsts and W. S. Harris: A Study of Radiant Base board Heating in the I = B = R Research Home (University of Illinois, Engineering Experiment Station Bulletin No. 358, 1945). ' *1 = B = R Testing and Rating Code for Finned-Tube Type Radiation (Institute of Boiler and Radiator Manufac turers, 1951, 1st ed., with addenda, 1954). : . - ` ASHVE code for testing radiators (ASHVE Transactions, Vol. 33,1927, p. 18). (This code was withdrawn in 1956.) 'Commercial Standard .for Testing and Rating Convectors (U: 8. Department of Commerce, CS 140-47,' 1947). 'C. Brabbee: The heating effect * of radiators (ASHVE Transactions, Vol. 33, 1927, p. 33). *A. C. Willard, A. P. Krats, M. K. Fahnestock, and S. Konzo: Investigation of heating rooms with direct steam ra diators equipped with enclosures and shields (ASHVE Trans actions, Vol. 35, 1929, p. 77 or University of Illinois, En gineering Experiment Station Bulletin No. 192). A. C. Willard, A. P. Krats, M. K. Fahnestock, and S. Konso: Investigation of Various Factors Affecting the Heating of Rooms with Direct Steam Radiators (University of Illinois, Engineering Experi ment Station Bulletin No. 223). */ ~ B = R Testing and Rating Code for Baseboard Type of Radiation (Institute of Boiler and Radiator Manufacturers, August 1952, 2nd ed.). 'E. A. Allcut: Heat Output of Concealed Radiators (Uni versity of Toronto, School of Engineering Research Bulletin No. 140, 1933). **K. F. Hubert: Heat Emission from Radiators (Cornell University, 1C7I Engineering Experiment Sta-tion Bulletin No. 24. ^ " v*. oc*eiua. tCSU Ol luuuLWir (ASHVE Transactions, Vol. 33, 1927, p. 41). **J. R. Allen: Heat loss from direct radiation (ASHVE Transactions, Vol. 26, 1920, p. 11). . " A. P. Krats: Humidification for-Residences (University of Illinois, Engineering Experiment Station Bulletin No. 230. p. 20). .' BIBLIOGRAPHY A. C. Willard, A. P. Krats^and M. K. Fahnestock: ASHVE Research Report No. 926--The application of the eupatheo- scope for measuring the performance of direct radiators and convectors in terms of equivalent temperature (ASHVE .Transactions, Vol. 39, 1933, p. 303).. . W. J. McConnell and C. P. Yagloglou: The Kata ther mometer--its value and defects (U. S. Public Health Service Report, Reprint No. 953, September 5, 1924, p. 2293). C.-E. A. Winslow and Leonard Greenburg: The thermo- integrator--a new instrument for the observation of thermal interchanges (ASHVE Transactions, VoL 41, 1935, p. 149). C.-E. A. Winslow, A. P. Gragge, Leonard Greenburg, I. M. Moriyama, and E. J. Rodee: The calibration of the thermo- mtegrator (The American Journal of Hygiene, July 1935, p. T. Bedford and C. G. Warner: The globe thermometer in studies of.heating and ventilation (The Journal of Hygiene, Vol. 34, No. 4). . ' Residential baseboard radiation (Reference Section, Air Conditioning, Heating and Ventilating, November 1957, p. 81). Commercial and industrial finned-tube radiation (Reference Section, Air Conditioning, Heating and Ventilating, December 1957, p. 71). ; CHAPTER 15 UNIT VENTILATORS AND UNIT HEATERS Unit Ventilators.- Classification, Ratings, Capacity, Requirements, Application, Control, location, fxhaust Vents, Window Downdraft Prevention, Mechanical Cooling; Unit Heaters: Classification, Application, Heating Medium, Type, location, Sound level. Ratings, Control, Piping, Maintenance. NIT ventilators and uuit heaters are discussed in this Ventilators.1 .This code requires OF entering air temper U chapter. The types, characteristics, method of rating, ature, unit fan operating at rated speed with standard louver and procedures for selection and application of these prodo r grille on the outlet, and dry saturated steam at a temper ucts are described. .- ature at the unit corresponding to a pressure of 16.7 psia UNIT VENTILATORS (218.5 F). The standard air rating of the unit is the delivery in cubic-feet per minute, converted to standard air at 70 F. The term unit ventilator denotes an assembly, the principle functions of which are to heat, ventilate, and cool a space by the introduction of outdoor air in quantities up to 100 percent of its rated capacity. The heating medium may be steam, hot water, gas, or electricity. The essential elements of a unit ventilator are fans and motor, heating element, dampers, filters, and outlet grilles (or diffusers), all encased in a housing. . - Unit ventilators are used primarily in schools, meeting rooms, offices and other areas where the density of occupancy indicates the need for controlled ventilation. The typical unit is equipped with a system of control that permits the heating, ventilating, and cooling effect to be. varied while, The anemometer air rating is peculiar to school venti lation. It originated as a convenient field measurement for checking air quantities, and is the basis of rating for venti lation requirements under some state and local building codes. The anemometer rating (air capacity) is obtained by averaging the air velocities obtained by an anemometer (propeller or averaging type) held over equal subdivisions of the outlet grille at a distance of 2 in. from the grille, and multiplying the average velocity by the gross area of the grille. The anemometer rating is based on the final temper ature of the air leaving the grille while the unit is delivering outdoor air and recirculated air in the proper proportion and the heating element is supplying heat as specified. This the fans are operating continuously. In normal operation, the discharge air temperature from a unit is- varied in ac cordance with the room requirements. When heating is required, the air delivered is above room temperature. When the heat generated within the room by occupants, lights, sun, etc., is sufficient to cause overheating, the temperature of the air delivered is below that of the room. It is customary to equip unit ventilators with control.devices that prevent the delivery of air at a temperature low enough to cause discomfort. Classification The various types of unit ventilators can be classified according to the three following methods: I.Heating Medium. Four-types of heating elements are used: (a) steam, (b) hot water, (c) gas-fired, and (d) electric. 2. Type of Unit. Under this classification there are three basic types to be considered: (a) Floor-mounted type, (b) ceil ing-mounted type, and (c) auditorium type which are used in vertical, horizontal, or inverted positions. Figs. 1 and 2 show typical floor-mounted units. Fig. 3 shows a typical ceiling- mounted unit, while Fig. 4 shows a typical auditorium-type unit in horizontal position. .. * 3. Arrangement of Elements. Unit ventilators may be of the (a) draw-through, or (b) blow-through arrangement. Fig. 1 shows a typical draw-through unit and Fig. 2 shows a typical blow-through unit. Ratings of Unit Ventilators Unit ventilators are customarily cataloged with two rat ings: the standard air rating and the anemometer air rating. The standard air rating is obtained in accordance with the ASHAE Standard Code for Testing and Rating Steam Unit Fig. 1.... Typical Floor-Mounted Unit Ventilator-- Draw-Through Type 213 x' 214 CHAPTER 15 1959 Guide method of rating is subject to error from differences in types and calibration of instruments, grille design, and the care with which the rating test is conducted. Because of this, the standard air rating is used by manufacturers to rate unit ventilators. Table 1 shows the air delivery capacities by the two methods of rating and the approximate room heating equiv alent in square feet of direct radiation (EDR) of an inter mediate size of heating element. Heating elements are avail able for higher and lower capacities. Heating Capacity Requirements for Unit Ven tilators ' Since a unit ventilator has the dual function of introducing outdoor air for ventilation and maintaining a specified room temperature, the heat required by the unit may be similarly divided into (1) heat required for ventilation H. and (2) surplus heat H,. The surplus heat is available for main- tuning room temperature. If auxiliary radiation is installed, the surplus heat requirement may be reduced by a corre sponding amount. The sum of H. and H, is the total heat Hi to be supplied by the-unit ventilator. These quantities of heat are related by the following equations: . H, - 0.24 W (t - f.) . H, - 0.24 W {I, - t.) B, - H, - H, = 0.24 W {l, - t) . . (1) (2) (3)' W - d60Q (4) B, - H, + 0.24 d 60 Q (t - i.) (5) Fig. 3 .... Typical Ceiling-Mounted Unit Ventilator where '. d = density of air, pounds per cubic foot (0.075 lb per cu ft for Standard Air by definition). H, *= surplus heat, Btu per hour. . H, = heat required to warm air for ventilation, Btu per hour. ' . B,= total .heat requirements for both heating and ven tilation, Btu per hour. Q TM volume of air handled by the ventilating equipment, cubic feet per minute. l " temperature to be maintained in the room, Fahren- ' heit . - . t. -- outdoor temperature, Fahrenheit. . t/ -- temperature of the air leaving the unit, Fahrenheit. W " weight of air circulated, pounds per hour. 0.24 -- specific heat of air at constant pressure (approximate value). . Example 1: The heat los of a certain room is 24,000 Btu'per hour, and the ventilating requirements are 1000 cfm. If the ropm temperature is to be 70 F and all air is taken from the outdoors at OF, what will be the total heat demand on the unit if it is required to provide for both the heating and venti lating requirements (combined system)? Solution: Since the surplus heat is available to replace the heat loss of the room, B, * 24,000 Btu per hour. Substituting in Equation 5: . ' H, = 24,000 + 0.24 X 0.075 X 60 X 1000 (70 - 0) . = 09,600 Btu per hour tf - --------------^0 '----------- + 70 - 92.2 F ' 0.24 X 0.075 X 60 X 1000 . Fig. 2____Typicol Floor-Mounted Unit Ventilator-- Blow-Through Type w Unit Ventilators and Unit Heaters 215 Toble 1 ....Typical Capacities of Unit Ventilators for an Entering Air Temperature of 0 F . - Cubic feet of air per minute Anemom eter Standard air rating Total capacity ea square foot, equivalent direct rodietion Capacity ovariable for booting the Final air room, tqoere foot temperature equivalent direct F radiation 750 1000 1260 1560 500 750 . 1000 1250 214 320 427 534 56 95 84 95 112 95 141 95 If in Example 1 & 1000 cfm (Standard Air) unit were required, but only 25 percent of the air introduced were outdoor air, the solution is: '. air handled, it is posable to obtain satisfactory cooling in mild weather. Table 2 gives, recommended room volume cir culation rates for different types of spaces served. For rooms facing East, South or West, higher values should be used. The minimum amount of outdoor air for ventilation is determined after the total air capacity has been established. It may be governed by state or local codes or may be cal culated by the engineer to meet the ventilating air needs, of the particular application. ' The heating capacity of a unit to meet the beating require ment can be determined from manufacturers tables. Selec- ' tion of heating capacity should always be made after deter mining the basic size of unit by selecting the unit air capacity. Automatic Control of Unit Ventilators H, = 24,000 + 0.24 X 0.075 X 60 X 0.25 X 1000 (70 - 0) = 42,900 ------2i000_----- + m_s2_2 : 0.24 X 0.075 X 60 X 1000 The only difference from Example 1 is that the ventilation load has been reduced. Heating Capacity Ratings - Heating capacity ratings for steam unit ventilators are obtained in accordance with the ASHAE Standard Code for Testing and Rating Steam Unit Ventilators' Under this code the capacities are established for varying air entering temperatures in addition, to .the standard rating. Capacity ratings include the entering air temperature, the total heat ing capacity, the surplus or heating capacity, and .the final air temperature. ' Hot water unit ventilators have heating capacity ratings- based on various entering water temperatures, flow rates or temperature drops, and entering air temperatures. Gas-fired unit ventilators'have beating capacity ratings obtained in accordance with regulations established by the American Gas Association. Heating capacities include the total heat input and the total heat output, in Btu per hour, for various entering air temperatures. Electric unit ventilators have heating capacity ratings based on the heat input to the electric heating element, in kilowatts or Btu per hour. The air capacities of hot water, gas-fired, and electric unit ventilators are obtained in accordance with the ASHAE Standard Code for Testing and Rating Steam Unit Venti lators.1 Many different cycles of control are available. The principle'difference in the various cycles pertains to the amount of outdoor air delivered to the room during normal periods of occupancy. Usually a room thermostat controls both a valve to regulate the heat supply and a damper to regulate the' supply of outdoor air. An air-stream thermostat in the unit prevents the discharge of air below the desired minimum temperature. Unit ventilator control cycles provide the proper sequence for the following stages: Warm-up Stage. Ail control cycles function to provide rapid warm-up by having the units provide full heat with the outdoor damper closed. Thus 100 percent room air is recirculated and heated , until the room temperature ap proaches the desired temperature level. Heating and Ventilating Stage. As the room temperature rises into the operating range of the thermostat, ventilation is accomplished by the partial or complete opening of the outdoor air damper according to the cycle used. Auxiliary - heating equipment is shut off. As the room temperature continues to rise the unit ventilator heat supply is throttled. Cooling and Ventilating Stage. When the room temper ature rises above the normal level, cool air is discharged into the room. The room thermostat accomplishes this by throt tling the heat supply, finally shutting it off, and opening the outdoor air damper to prevent overheating of the room. The air stream thermostat frequently takes control during this stage to prevent the discharge temperature from falling below a set level. The three basic cycles of control commonly used are as follows: Cycle X. 100 percent of outdoor air is admitted at all times except during the warm-up stage. Applications of Unit Ventilators Items to be considered in the application of unit venti-. 1ators are: (1) unit air capacity, (2) percent minimum out door air, (3) heating capacity, (4) cycle of control, and ' (5) location of unit. The primary considerations in the selection of the unit air capacity are the mild weather cooling capacity and the number of occupants in the space. Other factors to be con sidered are state and local code requirements, volume of the room, density of occupancy, and the usage of the room. A safe rule for determining unit air capacity is to allow a total air quantity of 30 cfm per person, or six to nine room air changes, per hour, whichever is greater. With this quantity of Table 2.... Recommended Outdoor Air Capacities for - Mild Weather Cooling For North Exposure Type of cpoce J .. ^ Recommended outdoor air delivery--room volume* per hour Classrooms Laboratories, Forge Shops MetaJ Working Shops Offices Card Rooms, Lodges Private Offices * Cafeterias & Kitchens 6-9 1 6-8 ' 6-8 6-8 6-0 6-9 4M-7 216 CHAPTER 15 1959 Guide Cycle Y. A minimum amount of outdoor air (normally 25 to 50 percent) is admitted during the heating and ventilating stags This percentage is gradually increased to 100 percent, if needed, during the cooling and ventilating stage. Cycle Z. Except during the warm-up stage a variable amount of outdoor air is admitted as needed to maintain a fixed tem perature of the air entering the heating element. This is con trolled by the air-stream thermostat Which is set tow enough (often 557) to provide cooling when needed. Night Control . For maximum economy it is general practice to maintain the building at reduced temperature at night and over weekends and vacations. Several control arrangements to tuor>mpiih this are in common use. One uses the unit-as a convector at night. Another turns the fans on and off as in the case of a unit heater whenever the unit convective capacity is insufficient. Still another arrangement uses'the convective capacity of the unit supplemented by the con vective capacity of auxiliary equipment installed within the . room. More elaborate arrangements are available, permitting operation at daytime temperatures.in some spaces and low ered temperatures in others for maximum economy during night occupancy of part of the building. For general infor mation on controls, see Chapter 43. Location of Unit Ventilators The location of the unit is important. Wherever possible it should be placed, against the outside wall and near the centerline of the room. It is difficult to obtain proper airdistribution if the unit is installed either on an inside wall or in the corner of the room. Standard unit models- are set against the wail, or may be recessed into the wall; and dis charge the air stream upward. Ceiling models discharge the air horizontally. installed in the vent: opening to prevent cold air from enter ing through the vent. It has become common practice, where regulations per mit, to exhaust into the corridor through louvers in the classroom door, with powered or gravity exhaust from the corridor to the outdoors. Thus, the slight pressurizing of the building by the unit ventilators provides the force to Thnri. the entire building. It is. common practice also to use the exhaust from the classroom as secondary ventilation by passing the exhaust air through wardrobes and lockers. Many state and local codes make this arrangement manda tory. ... Window Downdraft Prevention Increasing use of large window areas has presented a win dow downdraft problem caused by chilled air flowing down the windows and into the occupied areas of the room. Three - basic means of combatting these downdrafts have been de- veloped for use with unit ventilators. These are shown in Fig. 5 and operate as follows: ` Window riff heating employs finned radiation of moderate capacity installed along the wall under the window area. Heated air rises by convection upward and counteracts the downdraft by tempering it and diverting it upward to elimi- nate the cold draft. * -. Window sill recirculation is obtained by placing the retiirn air intake along the window sill. Room or return air to the unit includes the cold downdrafts, takes them out of the . occupied area of the room and thus eliminates theproblem. Window stU discharge directs a portion of the unit venti lator discharge air into a delivery duct along the sill of the window. The unit discharge air, delivered vertically at"the window sill, provides room-wide air distribution and com bats downdraft by upwardly-directed streams of air; **'` Air Exhaust Vents , . Unit Ventilators For Mechanical Cooling The location and size of exhaust vents' are not of partic ular importance on systems employing unit ventilators. However, many states have regulations which require vents in public buildings. When vents are used, it is important that they be sized and located properly. Vents should be fitted with maniiaj dampers so that the exhaust can be regulated for proper air distribution. Back-draft dampers should be With increased use of school buildings during the summer months, some school building programs incorporate mechan ical cooling or provisions for including it in.the future. In either instance, the unit ventilators provide.the same func tion during the heating season as the unit ventilators previ ously discussed in this chapter, using hot water as the. heat ing medium. Chilled water is used to provide summer air ; ] i jj i j ! ; ' - > fig. 5.... Three Methods of Preventing Window Downdraft Unit-Ventilators and Unit Heaters 217 conditioning. Units designed only for heating and ventilating Unit heaters are used principally for heating commercial are not suitable for use with chilled water. When provision and industrial structures such as garages, factories, ware for future mechanical cooling is made, the supply and re houses, showrooms, stores and laboratories, and, for heating turn piping, piping insulation, unit ventilators and controls corridors, lobbies, vestibules, and similar auxiliary spaces in are usually installed initially as required for complete air all types of buildings. conditioning. Water chillers, cooling towers, or evaporative . Unit heaters may be applied to a number of industrial condensers, and associated accessories are installed' later * processes, such as drying and curing, in which the use of when mechanical cooling is required. heated air in rapid circulation with uniform distribution is of particular advantage. They may be used for moisture ab UNIT HEATERS sorption, such as fog removal in dye houses, or for the pre The term unit heater denotes an assembly of elements, the principal function of which is heating. The essential elements of a unit heater are a fan and motor, a heating element,1 an enclosure, and a directional outlet. Filters, dampers, duct collars, combustion chambers, and flues may also be in cluded. Some types are shown in Figs. 6 to 13. vention of condensation on ceilings or other cold surfaces of buildings in which process moisture is released. When such conditions are severe, it is necessary that the units be equipped to draw air from outdoors in sufficient volume to ' provide a rapid air change, and that they operate in con junction with exhaust ventilators or fans for exhausting the moisture-laden air. (See discussion of condensation in Chap Classification............ .. - ter 10.) . '- ' The'various types*of unit heaters in present use can usu Factors Affecting Application ally be classified according to one or more of the following methods: - - 1. By heating medium: Under this classification there are five heating media to be considered: (o) steam, (6) hot water, (c) gas, (d) oil, (e) electric. ~2. By type of fan: Under this classification there are* two types of fans to be considered: (a) propeller and (b) centrif ugal. Propeller fan units. may be of the horizonlaUblow or down-blow type. Centrifugal fan units may be of the smaller cabinet type, or larger industrial type. Either - may be ar ranged for the delivery of air horizontally, or vertically up or down. * . 3. By arrangement of elements: Under this-classification there are two types of units to be considered: (a) the dratothrough type, in which'the fan draws air through, and (b) the blow-through type, in which the fan blows air through the heat ing element. Direct-fired unit heaters are always of the blowthrough type. . There are four major factors to be considered in the ap plication of unit heaters: (1) the heating medium to be employed, (2) the type of unit, (3) the location of the unit for proper heat distribution and (4) the permissible sound level. Heating Medium ' The selection of the proper heating medium is usually de termined on an economic basis, and requires an examination of the first cost, the operating cost, and the conditions of use. Steam and hot water unit heaters are relatively inexpensive, but require a boiler plant and piping system, tbe per-unit cost of which generally decreases as the number of units in stalled increases. Gas- and oil-fired units are more costly, but the'fuel lines and vent flues required are comparatively Application inexpensive, and the overall installation cost will usually be lower where a small number of units is used. Electric units - Unit heaters have three principal characteristics, as dis tinguished from gravity heating units: (1) relatively large are relatively inexpensive to purchase and install, but are usually'associated with a high operating cost per Btu output heating capacities in compact casings, (2) the ability to pro unless electric rates are very favorable. ject heated air in a controlled manner over a considerable distance, and (3) a relatively low installed cost per Btu Steam or hot water units are most frequently used in new installations in which the number of units is large enough to output. They are therefore usually employed in applications where the heating capacity requirements, or the physical justify the expense of a new boiler and piping system, and in existing installations or additions in which the system is volume of the heated space, or both, are larger than those of sufficient capacity to handle the additional load. High- that can be. adequately or economically handled by gravity . pressure steam or high-temperature hot water units are usu heating units. ~ ally employed in larger installations or where a high tem Where the heating capacity requirement is large, the in- . perature medium is also required for - process work. stallation of a small number of unit heaters will usually Low-pressure steam and conventional hot water units are prove more economical than will the use of a multiplicity of usually installed in smaller installations and in those pri gravity heating units of the same total capacity. Where the marily concerned with comfort heating. volume of the space is large, and especially where ceilings are high, unit-heaters can provide comfort through uniform heat distribution, and economy of operation by confining of the heat to the occupied zone and eliminating stratification Gas-fired and oil-fired unit heaters are usually preferred in installations in which the number of units required does not justify the expense of a new boiler and piping system, where the space or the time required to construct a new 'in a manner which is difficult to attain with gravity radiation. boiler plant is not available, or where individual metering Unit heaters located overhead permit 100 percent utiliza of the fuel supply is required, as in a shopping center. Gas- tion of floor space. They may often be used to advantage in fired units are usually of the horizontal propeller type or the specialized applications requiring spot heating, or intermit industrial centrifugal type. Oil-fired units are largely of the tent heating, such as the blanketing of outside doors in in industrial centrifugal type! Some codes limit the use of di dustrial plants, or in corridors and vestibules. Unit heaters . . rect-fired unit heaters in certain applications. are also employed where filtration of the heated'air is re-'.-, . Electric unit heaters are used where low cost electric power quired, and they may be modified to provide ventilation is available, or for isolated locations, intermittent use, sup where the introduction of outdoor air is required. plementary heating or temporary service requirements. Typ- ' . =?.- IP' 218 fig. 6.... Propeller . .Fan Unit Heater---Horizontal-Blow Type Type--Valve Controlled Fig. 8.... Floor-Mounted Cen trifugal Unit Heater--Cabinet Type fig. 13 ... .Oil-fired Centrifugal. Fan Unit Heater--Floor Mounted Unit Ventilators and Unit Heaters 219 ical applications are ticket booths, watchmen's offices, fac same leaving air temperature as would be obtained from a tory offices/locker rooms, and other isolated rooms scattered lower temperature heating medium. over large areas. Electric units are particularly useful in In order to obtain the desired air distribution and heat isolated and untended pumping stations or pits where they diffusion, -unit heaters are commonly equipped with direc may be thermostatically controlled to prevent freezing tem tional outlets, adjustable louvers, or fixed types of diffusers. peratures. For a given unit with a given discharge temperature and Type of Unif outlet velocity, the mounting height and heat coverage can vary widely with the type of directional outlet, adjustable Propeller fan units are usually used in free-delivery ap plications where the heating capacity and distribution' re louver, or diffuser employed. - . Other factors which may influence the heat coverage must quirements can best be met by units of moderate output used singly or in multiples, and where filtration of the heated also be .considered. Obstructions, such as columns, beams, partitions, or machinery, either in .the discharge air stream air is not required. Horizontal-blow units are usually associated with low to moderate ceiling heights. Down-blow or in the approach area to the unit, can reduce the heat coverage substantially. The presence of strong drafts or units are employed in high-ceiling spaces, and where floor and wall space limitations dictate an out-of-the-way loca tion for the heating equipment. ". other air currents will also reduce the coverage. Exposures such as large glass areas, or outside doors, especially on the windward side of the building, require special attention, and Industrial centrifugal fan units are applied where heating capacities and space volumes are large, or where filtration of the heated air, operation against static resistance, or the introduction of outdoor air are required. Down-blow or horizontal-blow units may be used, depending on the re units should be arranged so as to blanket such exposures . with a curtain of heated air which will intercept the cold drafts. . For area heating, horizontal-blow unit heaters in exterior zones should be located so as to blow along the exposure or quirement. toward it at a slight, angle. Where posible, multiple units Cabinet unit heaters are used for applications where a more attractive appearance is desired. They are suitable should be arranged so that the discharge air streams sup port each other and create a general circulatory motion in for free delivery or low static pressure duct applications, may be equipped with filters, and can be arranged to dis the space. Interior zones under expoWd roofs or skylights should be completely blanketed. Down-blow units should be charge either horizontally, or vertically up or. down. arranged so that the heated areas from adjacent units over Location for Proper Heat Distribution lap slightly so as to provide complete coverage. . For spot heating of individual spaces in larger unhcated Location of the units for proper heat distribution is of utmost importance in the application of unit heaters. In general, the units must be selected, located, and arranged so as to provide complete heat coverage and at the same time maintain acceptable air motion and temperature inthe working or occupied zone. Proper application depends on a number of factors: the size, number, type and direction of blow of the units, the mounting height, the outlet velocity, the outlet temperature, the air volume and the type of di rectional outlet employed. Many of these factors are inter related, and manufacturers therefore publish data for spe cific units showing heat coverage and mounting heights for various outlet velocities and outlet arrangements. Such data ' should normally be consulted in-selecting unit heaters for a particular application. In general, however, mounting height and the area of heat coverage increase with increased air volume and outlet veloc areas, single unit heaters may be employed, but allowance must be made for the inflow of unheated air from adjacent spaces and the consequent reduction in heat coverage. Iso lation of such spaces by partitioning or enclosure is always desirable from a heating standpoint. Horizontal unit heaters should have their discharge out lets located well above the head level, and both horizontal and vertical units should be so applied that the heated air stream will be delivered to the occupied zone at tempera tures and velocities which are not objectionable. Where possible, units should be so located that the discharge air flow is into open spaces such as aisles and not directly on the occupants. '' - Manufacturers' catalogs usually give suggestions for the best arrangements of various unit heaters, recommended mounting heights, heat coverages for various outlet veloc ities, final temperatures,-and directional outlets. - ity, and decrease with increased final temperature. The mounting height may be governed by space limitations or by Sound Level the presence of equipment such as display or. ma Consideration must be given to the problem of noise chinery. Both noise and air velocity in the occupied zone generated by unit heaters if they are applied in spaces hav generally increase with increased outlet velocities and must ing a requirement for low sound levels. All unit heaters therefore be considered. generate some noise, and whether or not that noise will be The blow is dependent to a marked degree on the tem acceptable depends upon the type of space in which it is perature of air leaving the heater as well as upon its velocity applied. For example, units with noise levels acceptable in and volume. Increased final temperature will reduce the area a manufacturing plant might be too noisy for use in a of heat coverage and the mounting height. Care must be show-room. A unit heater for a particular application must exercised in the application of down-blow unit heaters. The therefore be selected for satisfactory sound level as well as higher the mounting height, the lower must be the outlet for adequate heating capacity and proper heat distribution. temperature of the air leaving the heater in order that, the heated air will be forced down into the occupied zone. Ratings of Unit Heaters Since the outlet temperature of air from a unit heater in It is standard practice to rate all types of unit heaters on creases with the temperature of the heating medium, unit the basis of the amount of heat delivered by the air in Btu heaters for high-pressure steam or high-temperature hot per hour above an entering air temperature of 60 F. water should be designed to produce approximately the Steam. Rating of steam unit heaters has been standard- A m. -f b l 220 CHAPTER 15 1959 Guide ized by a code1 in which the following items are the basis of rating: dry saturated steam at 2 psig pressure at the heater coil; air at 60 F (29.92 in. Hg barometric pressure) entering the heater; and heater operating free of external resistance to air flow. . The capacity of a heater increases as the steam pressure, increases, and decreases as the entering air temperature in creases. The heating capacity for any condition of steam pressure and entering air temperature other than standard may. also be determined by means of a standard procedure prescribed by this code. .' Hot Water. A standard for the rating of hot water type unit heaters has also been established by code* in which the following items are the basis of rating: entering water at 200 F; .water temperature drop 20 F entering air at-60F (29.92 in. Hg barometric presure); and heater operating free of external resistance to air flow. Variations in entering water temperature, entering air temperature and water differences in temperature of the air actually entering the unit from that being maintained in the heated area. This is especially true with down-blow unit heaters. In general, the temperature gradient (temperature difference per foot of elevation) when using unit heaters, is less than when using gravity heating units.' Higher velocity units and units with lower discharge air temperature, will maintain lower temperature gradients than units with higher discharge temperatures. Valve-con trolled or bypass-controlled units employing continuous fan operation will maintain lower temperature gradients than will units employing intermittent' fan operation. Directional Hg. 15 .... Unit Heater Connection for Low-Pressure Steam Open Gravity or Vacuum Return System Fig. 14..^.Unit Heater Connection to Low-Pressure Steam ' Closed Gravity System ` flow rate will affect capacity. This code prescribes .a method of translating the heating capacity as obtained under test conditions to other, conditions of. air and water temperature. Gas-Fired. Gas-fired unit heaters are rated in terms-of both input and output in accordance with the approval re quirements of the American Gas Association. Oil-Fired. Ratings of oil-fired unit heaters are based on heat delivered at heater outlet in Btu per hour. . . System Electric., Electric unit heaters are rated .on the energy input to the heating element, expressed in terms of kilowatts, or Btu per hour. . control of the discharged air from a unit heater can also be Effect of Resistance Upon Capacity. Unit heaters are customarily, rated at free delivery type units. If outside air an important factor in effecting satisfactory distribution of heat and reducing floor-to-ceiling temperature gradients. intakes, air filters, or ducts on the inlet or discharge are used/ a reduction in air and heating capacity will result be When some outdoor air is introduced, the temperature of the mixture of outdoor and recirculated air must be calcu cause of this added resistance to air flow, unless compensat ing changes are made in fan speed. This reduction in capac ity will depend upon the characteristics of the heater, and lated and used as the entering air temperature at the heater. For recirculating heaters located at the floor or with intakes at the floor, the temperature of air entering the heater on the type, design, and speed of the fans, so that no spe cific percentage reduction can be assigned for all. heaters at should be assumed to be the same as that to be maintained in the room itself. ' -' ` ` a. given added resistance. The heat output to be expected under other than free delivery conditions should be secured . Automatic Control of Unit Heaters from the manufacturer. ' ' The controls for a steam or hot water unit heater can Effect of Inlet Temperature. Ghanges in entering air tem either provide (1) on-off operation of. the unit fan or (2) perature will influence the total heating capacity, in most continuous fan operation with modulation of the heat out unit heaters and the final temperature in all units. Since put. ' ' . many unit heaters are located some distance from the occu " For on-off operation a room thermostat' is used to start pied zone, consideration should be given to the possible and stop the fan motor. A limit thermostat, often strapped 1! 3? Unit Ventilators and Unit Heaters 221 to the supply or return pipe prevents fan operation in the event heat is not being supplied to the unit. . Continuous fan operation eliminates the. intermittent blasts of hot air resulting from on-off operation, and the stratification of temperature from floor to ceiling which of ten occurs during the off periods. In this arrangement a pro portional room thermostat controls a valve modulating the heat supply to the coil or a bypass around the heating ele ment. A limit thermostat or auxiliary switch stops the fan when heat is no longer available. - Control of direct-fired and electric units is usually accom plished by intermittent operation of the heat source under Hg. 17.... Connection of Horizontal Unit Heater to Hot Water System CATE VM.VE' . PITCH DOWN PTTCH DOWN .AIR VENT WLVE Rg. 18----- Connection of Vertical Unit Heater to Hot . Water System . control of the room thermostat, with a separate fan switch to run the fan when heat is being supplied. For a more general discussion of automatic control, refer to Chapter 43. Unit heaters may be used in summer as a means of provid ing air motion. In such cases the source, of heat is shut off and the thermostat is provided with a bypass switch that will permit fan operation independently of the controls. Piping Connections For Unit Heaters Piping connections for steam unit heaters are similar to those for other types of fan blast heaters. The piping of unit heaters must conform strictly to the system require ments while at the same time permitting the heaters to function as intended. The basic piping.principles for steam systems are discussed in Chapter 26. Rapid condensation of steam, especially during heating-up periods, is characteristic of steam unit heaters. The return piping must be planned to keep the heating coil free of con densate during periods of maximum heat output, and the steam piping must be ample to carry a full supply of steam to the unit to take the place of that condensed. Adequate sizes of piping are especially important where a unit beater fan is operated under on-off control because the condensate rate fluctuates rapidly. Recommended piping connections for unit heaters*, are shown in Figs. 14 to 18. In steam systems the branch from the supply main to the heater should pitch toward the main, and be connected to its top to prevent condensation in the main from draining through the beater where it might reduce capacity and . cause noise. The return piping from steam unit heaters should provide a minimum drop of 10 in. below the heater so that the head of water required to overcome resistances of check valves, traps, and strainers will not cause condensate to remain in the heater. Dirt pockets shown in Figs. 14 to 16 are pflSRntiftl, and strainers are recommended as an additional means of re taining dirt and scale which might affect operation of check valves and traps. Return piping between the heater and strainer should be of the same size as the heater outlet. Strainers should always be installed in the steam supply line if the heater is equipped with the steam-distributing type of coils or is valve-controlled. An adequate air vent is required for low-pressure closedgravity systems. The vertical pipe connection to the air vent should be at least % in. IPS to permit separation of the water from the air passing to the vent. In vacuum systems, if thermostatic instead of float-andthermostatic traps are used, a cooling leg must be provided ahead of the trap. In high-presure systems it is customary to vent the air through a pet cock which is left slightly open at all tunes. Where possible it is advisable to install pressure reducing valves to permit operation of the heaters at low pressure. Traps used must be suitable for the operating pressure en countered. In connecting piping to hot water unit heaters, the piping should be pitched to permit escape of air to the high point in the piping where it can be vented to the atmosphere. An air vent at the heater is used to facilitate air removal or to vent the top of the heater. Provision should be made for complete drainage of the system, including nipple and cap drains or drain cocks where units are located below mams. Maintenance ;. Regular inspection based upon a schedule determined by the amount of dirt in the atmosphere will insure maximum ' economy in operation and maintenance of heating capacity. Heating elements should be cleaned when necessary by brushing or blowing with high-pressure air, or by using a steam spray. Removal of the heating element and washing with a mild alkali solution, followed by thorough rinsing with water, may be necessary in certain installations. Dirty fan blades may cause unbalance and vibration with consequent noise and damage to bearings. Hence, fan Hades should be cleaned when necessary. Vibration or noise may also be caused by improper fan position or loose set screws. There is considerable difference in the attention required by the various types of motors used with unit heaters. This is particularly true of lubrication, the instructions for which must be carefully followed for trouble-free operation. Ex cessive lubrication may cause lubricant to reach and damage the motor. An improper lubricant may cause failure of bearings. Instructions for care of the motor on any unit JTMjL 222 CHAPTER 15 1959 Guide heater should therefore be obtained from the manufacturer and should be kept at the unit. Fan bearings and drives must be given the lubrication and other attention specified by the manufacturer. If the unit is direct-connected, the couplings should be inspected pe riodically for wear and alignment. V-beit drives should have all belts replaced with a matched set if one belt shows wear. Periodical inspections of traps, check valves, and air valves, and the replacement of worn parts are important maintenance items. Strainers should.be cleaned regularly. When filters are incorporated in the unit, they must be cleaned or replaced when dirty. For prevention of corrosion in unit heaters, see Chapter 55, Corrosion and Water Formed Deposits, .Causes and Pre vention, in this edition, and also Bulletin 12, The Care and Maintenance of Steam and Hot Water Unit Heaters, pub lished by the Air Moving and Conditioning Association, Inc. REFERENCES 1ASHVE Standard Code for Testing and Eating Steam Unit Ventilators (ASHVE Transactions, Vol. 38, 1932, p. 25). *G. L. Larson, D. W. Nelson, and R. W. Kubasta: ASHVE Research Repost No. 938--Investigation of air outlets in class room ventilation (ASHVE Transactions, VoI. 38, 1932, p. 463). F. C. Houghten, Carl Gutberlet, and M.- F. Lichtenfels: ASHVE Research Report No. 1017--Air supply to classrooms in relation to vent flue openings (ASHVE Transactions, VoL 41, 1935, p. 279). * Standard Code for Testing and Rating Steam Unit Heaters (Adopted jointly by The American Society or Heating and Ventilating Engineers and Industrial Unit Heater Association, 1UHA Bulletin No. 10, January 1950, 2nd ed.). * Standard Code for Testing and Rating Hot Water Unit Heaters (Adopted jointly by The American Society op Heat ing and Ventilating Engineers and Industrial Unit Heater As sociation, IUHA Bulletin No. 11, April 1953, 2nd ed.). *G. L. Larson, D. W. Nelson, and 0. C. Cromer: ASHVE Research Report No. 958--Temperature gradient observations in a large heated space (ASHVE Transactions, Vol. 39, 1933, p. 243). G. L. Larson, D. W. Nelson, and John James: ASHVE Research Report No. 1011--Tests of three heating systems in an industrial type of building (ASHVE Transactions, Vol. 41, 1935, p. 185). Piping, Trapping and Venting Steam and Hot Water Unit Heaters (Air Moving and Conditioning Association, Inc., Bulle tin No. 15). . CHAPTER 16 UNITARY AIR-CONDITIONING EQUIPMENT Definitions, Classification, and Components of Unrf-fype Equipment, Remote and Self-contained Units, Room Air Conditioners, Ratings of Unit Air Conditioners, Application of Unitary Equipment, Unit Air Coolers HIS chapter presents the physical characteristics of To obtain the economies of factory production, component Tair-conditioning and air-cooling units; a suggested pro assemblies are available in the size ranges of greatest usage. cedure for selection of units; and some of the factors inIn addition to assemblies of high-side equipment in con volved in the application.of unitary equipment. In general, densing units, the fan-coil units are factory made in various factory-produced unit equipment can be obtained to accom types as indicated by the preceding definitions. plish all of the functions possible from field assemblies, but the If the condensing unit and the cooling and heating coil advantages of unit equipment are most apparent in small surfaces are carefully selected, and if proper consideration is and moderate capacities. Above 12,000 cfm capacity, or ap given to reduction of piping losses, the performance of the proximately 40 tons of refrigeration capacity, handling and assembly costs generally favor the use of field-assembled combined system will compare favorably with field assembled apparatus. A system tn which the air handling unit is units. Multiple application of unitary equipment is fre separated from the condensing unit, is called a remote sys quently justified for large gross tonnage installations where zoning or a minimum amount of ducts is desirable. tem. The conditioning unit is designated as a remote unit. Capacities of remote units usually range from 2 to 100 tons. DEFINITIONS The self-contained air-conditioning or cooling units are widely used in capacities through 15 tons, and are available The term air-conditioning unit has been loosely used as a name for all types of factory produced air-handling, cooling, or heating units. A joint committee1, * * on Rating Refriger ating Equipment has defined the various types of unitary equipment as follows: 1. A Cooling Unit is a specific air-treating combination con sisting of means for air circulation and cooling within prescribed temperature limits.' 2. An Air-Conditioning Unit is a specific air-treating combi nation consisting of means for ventilation, air circulation, air in larger sizes. Each model is designed for a specific cooling capacity and range of air delivery. Experience has demon strated that well designed and properly applied equipment of this type produces excellent results in commercial comfort installations. In most designs of the larger self-contained units, the equipment can be adjusted to approximate the load calculations through a selection of the air quantity. An increase of air quantity in this type of equipment increases the sensible heat proportion, and a decrease of air quantity tends to provide a lower leaving dew point and a high pro cleaning, and heat transfer, with control means for maintaining temperature and humidity within prescribed limits.1 3. A Cooling Air-Conditioning Unit is a specific air-treating combination consisting of means for ventilation, air circula tion, air cleaning, and heat transfer, with control means for cooling and maintaining temperature and humidity within prescribed limits.1 portion of moisture removal. However, the usual field prac tice is to adjust the fan speed for quietness and air distribu tion rather than for ratio of latent to sensible loads as indicated by a load estimate. To meet the requirements of individual comfort in small rooms and offices, self-contained units, called room coolers, 4. A Self-Contained Air-Conditioning or Cooling Unit is one in which a condensing unit is combined in the same cabinet with ' the other functional elements. Self-contained air-conditioning units are classified* according to the method of rejecting condenser heat (water-cooled, air-cooled, and evaporatively cooled), method of introducing ventilation air (no ventilation, ventilation by drawing air from outdoors, ventilation by exhausting room air to the outdoors, or ventila tion by a combination of the last two methods), and method of discharging air to the room (free delivery or pressure-type). find extensive and economical application. These units are usually restricted to summer and intermediate season op eration, and range from to 1 Vt tons of refrigeration capacity. A special application of remote units is found in the unit air cooler which is used extensively in refrigeration work. Its primary function is to reduce temperatures in insulated and sealed storage spaces, and humidity control is a sec 5. A Free Delivery Type Unit takes in air and discharges it directly to the space to be treated without external elements which impose air resistance.1 . 6. A Pressure-Type Unit is for use with one or more external elements which impose air resistance.1 7. A Forced-Circulation Air Cooler is a factory encased assembly of elements by which heat is transferred from air to refrigerants* ondary consideration. Because of the small temperature dif ferences between the coil and room temperatures, unit coolers handle three to five times as much air per ton as remote units used in air conditioning. The attic fan or exhaust fan is sometimes referred to as a cooling unit, but since it contains no element of heat trans fer, it is treated in Chapter 22, Fans. CLASSIFICATION OF UNIT-TYPE EQUIPMB^IT COMPONENTS OF UNIT-TYPE EQUIPMENT Field assembled apparatus as described in Chapter 19 can be designed in shape, size, and capacity for any application, with tlie refrigeration and heating system exactly balanced to a specific load condition. The unitary equipment is designed for the air-conditioning loads of most common occurrence. Highly special projects and projects of infrequent occurrence may require fieldassembled equipment for best results. Field modifications 223 224 CHAPTER 16 1959 Guide Fig. \ . Horizontal Remote Type Unit Air Conditioner generally prove inadvisable except by the most experienced engineering personnel. The basic design considerations of unitary equipment are discussed in the following paragraphs. Remote Units Remote units can be obtained in two general classes, . horizontal as shown in Fig. 1 and vertical as in Fig. 2. The construction of both is essentially the same, except for the drain pan and filter locations. Casings. Casings are generally constructed of sheet metal with angle iron frames and with removable panels for access to coil connections, blower bearings, filters, and drain. Casings should be airtight. Panels should be tight-fitting with <iam or similar fastenings for easy opening. Panel openings at coils for heavy units should be large enough to receive coils after the casing is suspended. Frames should be fitted with lugs strong enough to suspend horizontal units. Nonmet&llic casings are of advantage in small remote units for reducing sound, particularly when propeller-type fans are used. ' Insulation. Remote units are available with waterproof and verminproof, sound and heat barrier insulation on the inside, of the casing. They are also available with flanges and flanged access doors to permit insulation after installation. . Drain Pans. Because of the corrosive effect of mild picric, carbonic, and sulfurous acids absorbed by condensate, drain pans are usually made of 14 gage or heavier metal. They should be hot dipped galvanized after fabrication, or other wise treated to resist corrosion. Some manufacturers extend the drain pan under the entire unit, but in any case it should extend far enough to catch any condensate carried over from the coils. The drain connection should be readily ac cessible for cleaning and, in air-conditioning work, should be generously sized and trapped. Some municipal codes re quire a minimum size of Wa IPS. Blowers. The usual practice among manufacturers is to use blowers having external resistance capacity in keeping with the size and type of application for which the unit is de signed. For example, the larger self-contained air condi tioners have blower and motor arrangements for delivering the design air quantities against the larger external static pressures that are encountered when applying these units . for use with supply and return-air duct systems. In a well designed unit, the relation of the blower and the coil surface is arranged, through testing, to assure adequate uniformity of air distribution over the heat-transfer surface. Some of the smaller suspended-type units. Fig. 3, use propeller fans with a trailing edge blade in order to obtain required pressure characteristics with quiet operation. Since most of the motors driving these fans are direct-connected and use brushes for starting, adequate access should be pro- viueu tor inaiiitou^riff. and inspection. Cooling Coils. The cooling and dehumidifying coils used in unit air conditioners are essentially the same as those used in central station units. A proper balance of coil capacity with the other-components of the packaged air conditioner is an essential of good design and performance. Ample coil ca pacity is a requirement for good operation at light loads and low air quantities. Where multiple circuits are used in the larger coils, equal distribution of the cooling medium to the various circuits is vital in order to develop full capacity of the coil. The cooling coils also perform the function, of dehumidification. To pre vent carryover of condensate, some coil designs require eliminator sections even at the normal face velocities of 400 to 600 fpm. . In addition to condensing the moisture out of the air, the design and arrangement of the cooling coil should provide for quick and effective draining of the condensate into the pan. Proper manufacturing practices to provide for uniform fin spacing and laboratory development to detennine coil- surface arrangements are among the requirements for good drainage from the cooling and dehumidifying coils of self- contained air conditioners. Heating Coils. Heating coils of unit air conditioners are usually conventional blast coils, and can be obtained with or without non-freeze steam distribution features. They usually match the cooling coils in face area, and are one or two rows deep depending on the heating requirements. Where coils are selected for hot water and have more than two rows of tubes, the air resistance and the space requirements of the cooling and heating coils should be carefully checked. Humidification. Spray-type humidifiers are usually used in remote systems, but in some cases pan-type humidifiers or steam humidifiers are also used. Some condensation on the inside of the unit casing may occur with possible water damage if the unit is located in a cold space without ade quate insulation. Spray-type humidifiers should be located so that no carryover of moisture occurs. Filters. It' is almost axiomatic that all units should have filters. Some small suspended units of 1 ton capacity or less, with low coil-face velocities and propeller fans, are equipped Fig. 2 .... Vertical Remote Type Unit Air Conditioner 5 j? Unitary Air-Conditioning Equipment 225 Fig. 3 .... Suspended Propeller Fan Type Unit Air Conditioner Fig. 5 .... Remote Floor Type Room Unit Air Conditioner only with lint screens or operate without filters, but in them the coils must be periodically cleaned and there is constant danger of clogging of the drain, with the possibility of water damage. Filters used are usually of the throw-away type, although cleanable filters are available for most of the larger units. Care should be taken to insure adequate filter surface, since the cross-sectional area of the unit is seldom adequate for filter area. V-shaped or staggered filter arrangements are quite commonly used to increase filter area. Motors. In some units where the motor is mounted inside, adequate access for maintenance and clearance for tightening belts are imperative. When motors are mounted in this manner, the heat equivalent of the motor input must be added to the beat load to be absorbed by the system, and this requires a lower exit air temperature at the coils. Usually, however, the motor is located outride of the casing where it is readily accessible for service. In this case, only the brake horsepower required by the fan is transformed into heat to be included in the load calculations. - '" In either application, motors should be selected with ade quate horsepower to handle the design volume of air against the resistance of the system when the coils are wet, and then checked against the possible horsepower requirements for the increased volume of air obtained when the coils are dry. Other Types of Remote Units Features of various other types of remote air conditioners are given in the following paragraphs. S]fray-Type Unit. Fig. 4 shows a spray-type unit used by designers who prefer air-washing and coil-wetting features. These units are equipped with a pump that sprays water or brine over the coils. Due to the direct Tniring of the con densate and the spray, provision must be made for overflow in summer and replacement of water evaporated in winter. Dehumidifying Units. In a further modification of spraytype units, absorbent brine solutions such as lithium chloride are used to remove moisture from the air. As explained in Chapter 42, the latent heat of the moisture removed is changed to sensible heat, so that coils must be used as after coolers to obtain the right dry-bulb temperatures. Factoryproduced units are also available for use with solid ad sorbents such as silica gel. - Another recent development as a manufactured item is the gmidl refrigeration-type dehumidifying unit for control of moisture in residential basements. Remote Room Units. For individual rooms, with cooling load requirements of Vt to lVi tons, remote units are avail * able in attractive-carings for installation within the room. A suspended type is shown in Fig. 3 and a floor type, such as is Fig. A .... Spray-Type Remote Unit Air Conditioner Fig. 6 .... Self-Contained Water-Cooled Air Conditioner 226 CHAPTER 16 1959 Guide usually installed in place of an existing radiator, is shown in Fig. 5. Furnished with chilled water from a central plant, these units offer a satisfactory method of conditioning ex isting office, hotel, and apartment rooms. These units may be obtained with filters and outdoor air connections, but for most satisfactory applications are used as supplements to the central systems that supply properly conditioned and filtered air to the areas served. Induction units, using primary conditioned air under pres sure to induce local circulation, are described in Chapter 19. SELF-CONTAINED UNITS A typical large self-contained air-conditioning unit is shown in Fig. 6. It is essentially a remote vertical-type con ditioner mounted on top of a sound-insulated enclosure con taining the condensing unit. Air distribution is obtained by means of grilles mounted in the discharge plenum, when the unit is located in the conditioned area. Duct distribution of conditioned air can be obtained by removing the plenum, connecting directly to the blower discharge, and safing the top of the unit. The beat generated by the compression of refrigerant gases and that given off by the electric motor are removed from the compressor compartment in four ways: (1) by the use of a water coil in the compressor compartment, (2) by utilizing the cold suction gases, (3) by drawing part of the return air through the compressor compartment; and (4) by circulating room air through the compressor compart ment by means of a fan attached to the motor shaft. Most self-contained conditioners are constructed with enough sound-isolation material for installation directly in the conditioned spaces of the higher-sound-level commercialtype of applications. Special sound treatment means are to be supplied as part of the installation when applying these conditioners to spaces having low sound-level requirements. Conditioners may be installed outside the conditioned area and the connecting supply and return-air ducts can be acoustically treated as required for the specific installation. ROOM AIR CONDITIONERS A room air conditioner is a factory-made encased as sembly designed primarily as a unit for mounting in a window or through a wail, or as a console, for free delivery of conditioned air to an enclosure and without ducts for conditioned air supply or return. It includes a prime source of refrigeration and dehumidification and means for circu lating and cleaning air, and may also include means for ventilating, heating, or performing other functions.' Most room air conditioners are used in residences and apartments, although many are installed. in small commercial estab lishments. A number of multistory buildings have been completely conditioned with room units. Although most room air conditioners are designed for con ventional window mounting, many are made for mounting in casement windows, walls, or as console types in front of windows or walls. In such units, the arrangement of the basic components is often quite different from that em ployed in window units because emphasis may be placed on minimum depth or height rather than on width. Since great strides have been made in recent years in the reduction of overall unit dimensions, the current trend is toward units that can be mounted essentially flush with the inner wall face and protrude very little beyond the outer face. A recent innovation is the small, light-weight portable room air con ditioner. Most room air conditioners have air-cooled condensers al though water-cooled versions have appeared from time to time. In air-cooled units, condensate disposal is typically provided by equipping the condenser fan with a slinger ring which picks up condensate and throws it on the condenser coil where it is evaporated into the condenser air stream and coincidentally provides some evaporative condensing effect. Sizes . Room air conditioners are available in capacities ranging from about 3000 Btuh up to 18,000 Btuh or more. Sizes have been popularly designated in terms of the nominal horse power of the compressor motor, although this is not neces sarily an accurate indication of unit capacity. Units are available in sizes up to 2 hp, with the Va hp and, more recently, the 1 hp units being most popular. . The National Electric Code* limits the amperage rating of motor-operated equipment installed on multi-outlet branch circuits to 50 percent of the circuit rating, and on single outlet branch circuits to 80 percent of the rating. For the typical 14-gage (15 ampere) house circuit, this effectively limits room air-conditioner amperage ratings for multi outlet and single branch circuit installations to 15 and 12 amperes respectively. .Many room air conditioners are de signed for maximum performance within these amperage limits, regardless of nominal compressor horsepower. Component Descriptions Although many different types and variations of com ponents have been used in room air conditioners, it is pos sible to give a fairly typical picture of current production. Hermetically-sealed refrigerant circuits are now universally employed, and the compressors are usually of the welded- shell reciprocating type operated by capacitor-start, ca pacitor-run, or permanent-split capacitor motors. Both evaporator and condenser coils are usually of aluminum plate fin and copper coil construction. Capillary tubes are normally employed as the expansion device, although valves are sometimes used for special purposes. Both centrifugal and axial-flow fans are used, sometimes one of each, with the latter equipped with a slinger ring for condensate disposal. One shaded-pole or permanent-split capacitor fan motor, mounted on the condenser side or in the partition, is fre quently employed to operate both fans although in some designs two fan motors are used. A throw-away or cieanable type of filter is standard equipment. Grilles and an increasing number of other parts are being constructed of plastic. A slide-out chassis, containing the complete refrigerant and air circuits, is often used. Nonflammable and nontoxic re frigerants (ASA B9.1, Group I Classification*) are used ex clusively. - Features A thermostat and adjustable louvers for directing the conditioned air have become standard features on most units. A ventilation or outdoor-air damper is almost always in cluded and sometimes an exhaust air damper. Two-speed fan motors are frequently used to give quieter operation dur ing off-peak load conditions. Special filters and other air puri fication devices are featured on some models. Some room air conditioners are designed as heat-pump units to provide heating during the intermediate seasons, or for year-round conditioning in some climates. Resistance 3 5' Unitary Air-Conditioning Equipment 227 heating has also been incorporated into some units for the same purpose. . Electrical Characteristics Room air conditioners are normally designed to operate on single-phase, 60-cycle power at 115, 208, or 230 volts. Units for the export market are made for 50-cycle operation. Attachment plug requirements, which are related to the National Electrical Code ampere limitations, are specified by Underwriters' Laboratories, Inc.* The rapid public acceptance of room air conditioners has presented special problems to the utility companies who must supply power to meet the electrical demands of these units during summer heat waves. As a result, recommended maximum starting currents and minimum power factors have been established for room air conditioners and are listed in ARl Standard 110-56. ' Rating Room air conditioners are tested for rating under the pro visions of the ASRE Standard 16-56* at standard rating con ditions of 80 F db and 67 F wb room air temperature and 95 F db and 75 F wb outdoor air temperature for air-cooled units. Rating requirements are specified in the ARI Room Air-Conditioner Standard 110-56. That organization is presently conducting a room air-conditioner rating compli ance program. Other Design Considerations Air-flow rates vary considerably, with evaporator air quan tities of 350-400 cfm per ton and condenser air quantities of 650-700 cfm per ton being approximately representative of current practices. Sensible heat factors usually average about 0.70, and performance factors (Btu per watt hour) about 6.5. Room air conditioners should be designed to operate sat isfactorily at the maximum conditions they might nof: mally encounter. They should also be expected to perform . without dripping or blowing of water from the unit. Stand ' ard test requirements for such considerations have been es tablished by ARI in ARI Standard 110-56. Safety requirements for room air conditioners are pre scribed in the American Standard Safety Code for Mechani cal Refrigeration B9.1 and the Underwriters' Laboratories Standard for Room Air Conditioners. Selection Many room air conditioners are sold over the counter without careful attention being given to matching the ca pacity of the unit with the requirements of the load. The ARI has available a fairly simple Cooling Load Estimate - Form for Room Air Conditioners* which can be used to make a reasonably proper selection. Most manufacturers also have cooling load calculation forms available and many have even simpler quick-selection charts or devices. Installation An installation accessory package is usually furnished with most units. These are designed so that an installation can be completed in an hour or so by one or two men using a few common tools. Accessory packages and wall sleeves are some times available for casement windows and through-wall mountings. The only connection that is necessary for air-cooled units is to insert an electrical plug into a convenience outlet of the proper rating. Controls for Room Cooling Units Control devices provided for self-contained cooling units generally will include all necessary means for automatic op eration. Provision is also made for adding auxiliary external controls, when desired. Remote units are not generally equipped with controls. Control of remote units and the ad dition of auxiliary controls for self-contained units can be made by application of the control principles outlined in Chapter 19 Central Systems for Air Conditioning and Chap ter 43 Automatic Control. RATINGS OF UNIT AIR CONDITIONERS Two standards have been used for rating and testing of ,lunit air conditioners: (1) Standard Method of Rating and Testing Air Conditioning Equipment covering all types of air-conditioning units except the self-contained type and (2) Standard Method of Rating and Testing Self-Contained Air Conditioning Units for Comfort Cooling* covering the self-contained type. (ASRE Standard Methods of Rating and Testing Air Conditioners, ASRE Standard 16-56, covers rating and testing of all types which operate nonfrosting when cooling and dehumidifying at standard rating condi tions.) The standard rating of a self-contained unit, for the condi tions specified in Table 1, includes all items which apply to the function of a unit such as: (1) name of unit, (2) func tions which unit performs, (3) data on cooling, (4) data on heating, (5) data on air flow, and (6) data on humidification. The standard rating conditions for unit air conditioners, other than the self-contained type, are identical with those in Table 1, except that entering wet-bulb temperature for eooling is expressed as 50 percent relative humidity (66.7 F wetbulb) instead of 67 F wet-bulb temperature. In addition, the saturated suction refrigerant temperature for comfort cool ing is specified at 40 F. This condition is omitted from Table 1 for self-contained units because it is not separately con trollable in the testing of a unit that includes the evaporator and condensing unit. APPLICATION OF UNITARY EQUIPMENT One of the chief advantages resulting from use of factory produced units is the saving in installation and field assembly labor, a factor that should always be kept in mind when selecting a location for these units. Because of their com pactness, the tendency exists to put them in closets, storage rooms, and other inaccessible places, where installation is so difficult that much of this cost advantage is lost. Access panels are provided on units for the proper servic ing and maintenance of the equipment. Adequate outside clearance at these panels is essential. Wherever there is dan ger of freezing of coils or clogging with dirt, sufficient clear ance should be available for replacing them without remov ing parts of the building. The outstanding source of difficulties in unitary systems is usually dirty filters. The characteristics of the light-weight fans used are such that air volume drops off rapidly with increase in static resistance. Since changing of filters is an unpleasant duty likely to be neglected unless it can be done easily, the operator should be at the same level as the filters, rather than under them, when they are being removed. Variable-pitch motor pulleys are usually provided for ad justment of the air quantity. The fans and motors of most 228 CHAPTER 16 1959 Guide Table 1 .... Standard Rating Basis for Self-Contained Air-Conditioning Units fuBcliani Typo* of (Mli (torn Rating Condition Description Valu* All All a Barometric pressure 29.92 In. Hg b Unit ambient and air Water-cooled, entering room--air air-cooled, and inlet evaporatively (1) Dry-bulb cooled condens- (2) Wet-bulb 80 F 67 F c Ventilation air See Note Cooling Water-cooled condensers d Water temperature entering unit e Water temperature leaving unit 75 F 95 F Air-cooled and evaporatively cooled condens ers f Air -entering outdoor air inlet (1) Dry-bulb (2) Wet-bulb 95 F 75 F g Unit ambient and to tal air entering unit 70 F Heating vided with h Heating medium, beating func pressure or temper tion - ature (1) Dry saturated 16.7 psia steam- (2) Water in 180 F (3) Water out 160 F i Unit ambient 70 F TTnmidi- vided with hu i -fying - midifying func tion Total air entering unit ' (1) Dry-bulb (2) Wet-bulb 70 F 53 F Air cir culation All k Filters New and clean /fete.* hail be os both ventilation and recirculated room air catenae at 80 F dry-bulb and 07 F vet-bulb temperature. (The Not* aa givea in the code haa been condeaaed in order to remove material aot pertinent to thia ehapter.) conditioners are selected for the usual range of external re sistances commonly used with the specific size of conditioner. The larger conditioners are capable of serving larger areas and therefore require fan and motor capacity for the greater external duct resistances that may be imposed on such condi tioners. ' When locating unitary equipment, floor and beam loadings should be carefully checked. Suspended horizontal .units can add 50 to 100 lb per square foot to the loading on the floor above. Should this floor be already heavily loaded, or be a roof structure designed for a 40 lb per square-foot snow load, excess beam deflection may occur and cause cracking of plaster or concrete fireproofing. A small fire, normally of little consequence, may cause a rupture of a heavily loaded structure and permit the equipment to drop with extensive property damage. Self-contained units should be carefully installed since their weights run as high as 200 lb per square foot. When they are installed in street floor shops, the extra precaution of placing a column beneath them in the base ment is an inexpensive method of reducing vibration, as well as providing insurance against overloaded floor beams. The services required for operation of unitary equipment should conform to the many restrictive, but necessary, local municipal codes. Existing buildings seldom are wired ade quately for the electrical load imposed by the starting of an air-conditioning compressor on any branch circuit. Even the smallest room cooler can draw enough current to reduce the voltage of a lighting circuit to the point where it is visibly apparent. This voltage drop may even affect the life of the unit due to the relatively slow starting. The cost of a sepa rate electrical circuit of adequate capacity from the main panel is more than justified; it is a necessary expense in the majority of installations. A water supply of adequate capacity and pressure is nec essary to prevent overloading of electrical equipment by high head pressures. The average city water supply pressure is adequate for installations up to the third floor. Since most water-cooled units require about 20 psd pressure, in cluding control valve losses, it is important that any units served by gravity from roof tanks be checked carefully if located less than 40 ft below the tank. Drain connections from condensers should flow to an open and properly trapped eink as required by most city codes. This prevents back pressures on the city water system in the event of condenser failure. A check valve should also be in stalled in the water supply as a further precaution against contamination. ' When installing small remote or self-contained units with outdoor air connections in buildings more than 6 stories high, the effect of wintertime stack action in elevator and stairwells requires special attention. This stack action is the cause of negative pressures on the lower floors, tending to draw cold air through the units, and positive pressures on the upper floors preventing adequate ventilation and disrupting air dis tribution. It can also cause annoying whistling at door open ings and lead to serious complaints in hotels and offices. Wherever the removal of such units is impracticable, it is important that carefully fitted, felt-edged dampers be in stalled in the outdoor air intakes and that they have ade quate locking devices. One further consideration when installing self-contained units in conditioned areas is to ensure that space is adequate for any maintenance or repairs to be required in future years. Sound Isolation Both suspended and vertical floor-mounted units can trans mit vibration through the supports. Wherever such trans mission of sound might be objectionable, the supports should be isolated through rubber-in-shear or other sound deadeners. (For design of suitable sound deadeners see section Con trolling Vibration from Machine Mountings in Chapter 25.) UNIT AIR COOLERS Unit air coolers are intended principally for product cool ing, but are often used for cooling spaces to low temperatures. They differ from normal air-conditioning units only in fea tures required to produce lower temperatures. In using such units, dry-bulb temperatures should be considered first, after which room moisture conditions and air distribution should If Unitary Air-Conditioning Equipment 229 be considered, depending on the product being cooled or stored. - Products to be cooled or stored may be divided into four general classifications based on their sensitiveness to moisture loss.* Selection of the proper temperature differential be tween storage-room air temperature and evaporating re frigerant temperature will produce adequate moisture con trol for all practical purposes. The differentials required for ' gravity circulation and for forced air circulation are differ ent, the latter requiring closer differentials. The four classes and differentials which have been successfully used are as follows: : Clots 1. Products requiring high room-moisture content, which are highly susceptible to moisture los3 and are being stored for extended periods, for example, eggs. Gravity Circulation Forced Air Circulation 18 F or less.. 6 to 9 F. Class f. Products similar to Class 1 but which are being stored only for a limited time as in retail stores where the turn-over is usually 3 days or less, for example, cut meats. Gravity Circulation* Forced Air Circulation ' 18 to 22 F. 9 to 12 F. Class 5. Products requiring moderate room moisture content and which are moderately susceptible to moisture loss, for example, carcass meats and some fruits. Gravity Circulation Forced Air Circulation . 21 to 27 F. 12 to 20 F. Class 4 Products from which there is a very low moisture loss or none at all and where room moisture content is not important, for example: canned goods, furs, woolens, bottled goods, dned fruits, foods packaged in good moisture, vapor barrier packages. . .. Gravity Circulation Forced Air Circulation 25 F and up. ' 20 F and up. When using Class 4 application,.with finned evaporators and automatic defrosting at each cycle of `the condensing unit, it is important to avoid using too wide differentials -with very low refrigerant temperatures. In many applications, prime surfaced evaporators.prove unsuitable for this type of defrost ing and .will require some positive method of defrosting. Unit coolers can perform satisfactorily in installations re quiring accurate control of relative humidity, air motion, and dry-bulb temperature, and thereby prevent excessive weight loss, mold and slime growth, arid moisture absorption by hygroscopic materials such .as dried fruits. Unit coolers, especially in the smaller sizes, are very simi lar in appearance to unit heaters. Copper, aluminum,' or steel prime or finned-surface tubes are used. Propeller or centrifu gal fans either blow or draw room air over the tubes: The fan arid coil are generally enclosed in a caring provided with a drip pan. The motor horsepower requirements are a func tion of resistance due to coil construction and arrangement, and air volume required. Fin. spacing is based principally on operating temperatures. For operation below 35 F, fin spac ing is preferably not more than four to the inch. Above 35 F it may run as high as 8 fins per in., depending on room tem perature-and refrigerant temperature used. Both direct ex pansion refrigerants and brine are used successfully-as cooling mediums. Unit coolers may be arranged for either free or duct de livery. Face velocities vary, depending principally upon the intended application of the unit. In the larger sizes particu larly, speed adjustment of the fan is generally provided to- permit variation of the air delivery. While unit coolers are usually installed in the storage space, remote installation com bined with appropriate ductwork may be required by space or other considerations. Units are available for floor, wail, or ceiling mounting, thus, providing an upward, downward, or horizontal discharge. Power, refrigerant, and drip pan con nections are required, plus additional connections for de frosting, if necessary. For storage temperatures below 35 F, some positive means of defrosting is mandatory. At 35 F or higher storage tem peratures, cycling of the condensing unit with low-pressure control at proper settings will provide automatic defrosting at each cycle. At above 35 F design refrigerant temperatures, frost and ice formation will not normally occur. . Various methods of defrosting are used. In one method, hot gas is supplied to the interior of the tubes uniformly through out the coil. The entire refrigerant circuit is thus contacted to obtain complete defrosting of all frosted surfaces. Electric defrosting generally involves the incorporation of heating ele ments within the construction of the coil, or the use of strip heaters in a dampered closed-air circuit. Warm water may be sprayed over the coil surface for defrosting. With storage temperatures above 32 F, defrosting may be accomplished by shutting down the refrigeration system and circulating the . room air over the coil. In every case, defrosting requires a cessation of refrigeration on the unit being defrosted. Where continuous operation of the system is desired,- a brine spray over the coil may be used unless it might damage the product in storage, or cause too much corrosion of room fittings, ducts,, etc. . ' . ' Ratings . Since various means of expressing unit cooler capacity.are utilized in the industry, different manufacturers suggest dif ferent methods of selection. The engineer should be aware of the conditions and factors which affect rating, selection, and performance of a cooler. These items are discussed in follow ing paragraphs. ' ' .. The refrigerating capacity of the unit may be' either gross or net, the latter being les than the gross by an amount equal to the heat equivalent of the input to the unit cooler motor. In either case, the capacity should be given for a particular air volume. Air throw data are also valuable. Dry or flooded rating conditions should be stated, as well as temperature level. The temperature level determines whether the coil surface is wetted or frosted, and it will also establish the refrigerant-side pressure drop for any given load applied to a specific unit cooler. The refrigerant-side pressure drop increases as the evaporating temperature de creases, and thus temperature level exercises a significant ef-* feet on the average coil-surface temperature and the conse quent condensing-unit selection. . Coil capacity rating is usually expressed as total heat ab sorbed with' no distinction between sensible and latent heat. The rating expresses the capacity in terms of Btu per (hour) (Fahrenheit degree temperature differential between 'the re frigerant and the air). The term basic rating may be used. This is the Btu per hour absorbed with one Fahrenheit de gree differential between room air and evaporator refrigerant temperature. When the total load has been obtained from the - load calculations, a temperature differential between the air and the refrigerant is selected. It is based on product classi fication previously discussed. The extent of dehumidification will be a function of this temperature differential. Moisture conditions in the storage space are dependent upon the cor rect selection of this temperature differential. It offers a quick and sufficiently accurate practical basis for coil selection. 230 CHAPTER 16 1959 Guide Where close control of relative humidity is desired, heating coils or electric heaters for reheat may have to be added. The use of air-conditioning psychrometric techniques is only re quired. for accurate humidity control. *' Cooling equipment is usually rated on the basis of the over all room-to-refrigerant temperature differential instead of using the intermediate average coil-surface temperature. If the tentatively selected unit cooler does not' possess the proper capacity, it may be possible to adjust the fan speed to a new air volume. At the new air volume and the new overall differential, the cooler may be able to deliver the necessary cooling capacity. If not, the procedure must be re peated with another size of unit cooler, the final selection be ing based on the proper balance between unit cooler and the condensing unit to maintain the Btu per hour heat removal and temperature difference at design room temperature.' Procedures for rating and testing room coolers are given in an ASRE Standard1 which establishes four groups of con ditions (numbered I to IV) under which units may be rated. Many manufacturers establish and publish their ratings in accordance with this standard in which forced circulation air coolers are classified according to air side surface conditions as (1) dry coil, (2) sprayed coil, and (3) spray (no coil); or according to type of air delivery to room as (1) free delivery fan, or (2) pressure fan. Natural convection air coolers are classified according to type as (1) external baffle, (2) built-in baffle, and (3) without baffle. ' - - Arrangement and Operation The refrigerant is usually supplied to the evaporator through a thermostatic expansion valve, thus obtaining dry expansion in the evaporator. In other designs, float-valve feeding is used as a' means of metering the refrigerant into the evaporator. The refrigerant circuit in the coil may be of the continuous-flow type from inlet to outlet, or it may have means for internal recirculation of the refrigerant. The coils having the dry-expansion or continuous flow from inlet-to- outlet circuits may be of the upward feed or the downward feed arrangements. Upward flow is generally regarded as pro ducing more refrigerant holding capacity and more-effective use of the Surface. However, with some refrigerants and in some systems, the downward-feed system has been found to produce better oil-return characteristics. Many direct-ex pansion installations use liquid-vapor heat exchangers to in crease the coil utilization without undue risk of returning liquid refrigerant to the compressor. Where two or more evaporator coils are to be attached to a single condensing unit, and different evaporator tempera tures are desired, a' back pressure valve may be installed to limit the minimum evaporating temperature of the warmer coils. This valve also finds application where fluctuation in the evaporator temperature prevents accurate control of air temperature and humidity. ... Except in product precooling, the objective of air distribu tion is to absorb the heat load as it comes into the room while maintaining a desirable degree of ventilation-air movement through hygroscopic cargoes that are not encased by vapor- barriers. In cold storage practice, this generally requires the securing of as uniform an air distribution as possible to every., part of the product zone, with employment of diffusion of air over the product and the prevention of direct blasts against the product. These requirements must be recognized when selecting the unit coolers and their outlets and when selecting the locations for the unit coolers. It is important to note that the quantity of air in motion in the refrigerated space is not only that passing through the coils. A quantity of air many times in excess of the air handled by the units is always set in motion by the induction effect of the moving cooled air. Therefore, in evaluating the velocity for any given area, the total air set in motion must be considered. It is a function of the type of outlet, the discharge air. velocity, and the unit location relative-to restrictive walls and product. Unit location is also important from the standpoint of oc cupant comfort, low-velocity outlets being preferred for floor type units. High-velocity outlets are acceptable in fur storage vaults, ice cream, hardening rooms, and other spaces where air motion is not an important factor. . In general, unit air coolers should not be suspended in front of door openings, or close to them where moist warm air will be drawn directly into the unit each time the door is opened, thereby causing excessive frosting and loss of capacity. Better performance will be obtained by placing the unit air cooler where the air will be discharged toward the door. If the shape of the space is such that this location would result in excessive air velocity over the product, then the location of the unit air cooler should be changed so that the air is discharged parallel to the wall in which the door is located. . .. Control of Unit Air Coolers .' ^ Although most unit air coolers ean be adapted to any con trol cycle, continuous fan operation is recommended to avoid stratification and wide fluctuations in space temperature. Should the unit be completely self-contained, control of the direct-expansion refrigeration unit may be obtained from the temperature of the recirculated air and from suction pressure. In the case of multiple unit systems supplied with refrigerant .or chilled water from a central source, a valve in the supply to each cooling coil may be controlled thermostatically from space temperature. . REFERB'ICES 'joint Committee of the American Society of Refrigerating Engineers, American Society or Heating and Ventilating En gineers, Refrigerating Machinery Association, National Elec trical Manufacturers' Association, and Air Conditioning Manu facturers' Association: ASRE Circular No. 13-42.* * Joint Committee of the American Society of Refrigerating Engineers, American Society or Heating and Ventilating En- .GiNEEEa, Refrigerating Machinery Association, National Elec trical Manufacturers' Association, and Air Conditioning Manu facturers' Association: ASRB Circular No. 16* * ASRB Standard Methods of Rating and Testing Forced- Circulation and Natural Convection Air Coolers for Refrigera tion {ASRB Circular No. 25-44). ' \ * Room Air Conditioners (Air-Conditioning and Refrigeration Institute Standard 110-56). ' . 1 National. Electrical Code (National Board of Fire Under writers Pamphlet No. 70, Paragraph 195). . -. * American Standard Safety Code for Mechanical Refrigera tion (American Standards Association, B9J-1953), TStandard for Room Air Conditioners (Underwriters' Labo ratories, Inc, UL484, September 1957, 2nd ed.). . * Methods oj Rating and Testing Air Conditioners (American Society of Refrigerating Engineers Standard 16-56). * Cooling Load Estimate Form for Room Air Conditioners (Air-Conditioning and Refrigeration Institute Standard 120-56). m Air Conditioning Refrigerating Data Book--Applications (American Society of Refrigerating Engineers, 1950-57, Chapter * ASRE has eoobined Cimlari No. 13HJ and No. 16 in ASRB Standard No. 14-66, tfttMi / Ratinf and Tub'n* Air Conditimm. . f CHAPTER 17 ELECTRIC HEATING Resistors, Heating Elements, Electric Heafrng Units, Electric Space Heating Applications, Types of Electric Heating Systems, - Equipment end Installation Methods, Calculating Capacities, Induction and Dielectric Heating, Power Considerations ELECTRICITY as a source of heat represents thermal into metal or plastic, and used in water heaters, ranges, and energy in a refined form, easily applied to space heat air heaters. - ing, and readily distributed and controlled. For many appli Cloth fabrics,, incorporating flexible resistor wires, are em cations, including use to supplement heating systems of other ployed for many low temperature purposes such as heating types, the compactness, simplicity, responsiveness, accuracy pads, sheets, blankets, aviators' clothing, and some radiant of control, safety, and cleanliness of electric heating may carry greater weight in choice of method than operating cost and initial investment. Electric heat often is more expensive bn a direct-heat-equivalent basis than heat from conventional fuels. Economical service requires careful application in the panel heating installations. Special incandescent lamps with tungsten or carbon fila ments and glass or quartz envelopes are designed to produce maximum energy in the infra-red portion of the spectrum and applied as radiant heaters. design of system, adaptation of building structure, choice of control devices, and in method of operation by the user. ELECTRIC SPACE HEATING APPLICATIONS . Using the power-to-heat conversion constant, 1 kilowatt Complete electric heating systems are now finding wide equals 3,413 Btuh, resistance heating calculations are-ex application not only in residences but also in many commer pressed directly in terms of kilowatt power requirements. cial and industrial establishments. Auxiliary electric space Definitions of Resistor, Hearing Element, and other terms heating is often used for convenience, for instance: (a) for applying to resistance electric heating practices will be found local use when the main heating system is shut down, (6) for in Chapter 1. local use where the main heating system is inadequate, (c) All equipment, materials, and construction used in electric for temporary heating, (d) for special conditions involving heating systems should comply with the-requirements of the separate or remote control, (e) for isolated locations, (/) for National Electrical Code, with local codes, and be listed as - cases where minimum initial cost is the dominant factor. approved by Underwriter's Laboratories Inc, or other recog Portable units readily satisfy some of these requirements. nized certifying agency. Compact electric heating units are sometimes installed in ELECTRIC HEATING UNITS main supply or branch ducts of central-fan steam and water systems to provide the final temperatures and relative hu An electric heating unit is a frame, casing, or other sup midities required for comfort or process air conditioning. porting means containing one or more heating elements, elec Electric heaters installed for use primarily in the heating tric terminal connections or leads, and electrical wiring and cycle can also be utilized for reheat in the cooling cycle. insulation, all assembled into a unit. There are many varie In control of systems, the flow of air over the electric heat ties of housing, material, and arrangement of heating ele ers should be constant while the input to the heaters should ments, operating temperatures,.ratio of radiant to convective be varied. This is necessary because of the basic difference heat delivery, directional control for radiation, natural or between electric heating and other methods such as steam ' forced convection, automatic or manual control, and electric heating. Steam is approximately a constant temperature load limiting features. Many specific types of units are dis source of heat at any given pressure, and, consequently, a cussed in the section Equipment and Installation Methods. change in air flow over a steam coil does not greatly alter RESISTORS AND HEATING B.EMENTS the coil surface temperature. Hence, the heat output of a steam coil varies in proportion to the air volume, but the Electric resistors usually are composed of metal-alloy wire surface temperature of the coil remains about the same. With or ribbons, non-metallic carbon compounds in rod or other electric heat the energy input and output are constant, and shapes, or printed circuits. Heating elements may have ex if the electrical energy input remains constant, the tempera posed resistor coils, mounted on insulators, metallic resistors ture of the heating elements will vary inversely with the air embedded within refractory insulation encased in a protec flow. Therefore, face and bypass dampers should not be used tive metal sheath, or a printed circuit encased in glass sheets. in electric heating, because the reduction in air flow and the Fins or extended surfaces may be used to add heat-dissipating corresponding rise in heater temperature would endanger the area. Elements are made in many forms. Strip elements are operating life of an electric heating element. . used for clamping to surfaces for heat transfer by conduction Automatic regulation of the electrical input is usually ac in some convection air heaters and some low temperature complished through a proportional-type step controller that radiant heaters. Ring and plate elements are common in elec energizes or de-energizes heaters in increments small enough tric ranges and many small air heaters. Metal or oxide con to prevent excessive cycling. .The electrical input per heater, ductive films on glass and ceramics have been used usually or step, is normally determined by the permissible change in in panel form. Tubular elements may be immersed in liquids, supply air temperature per step. High-limit thermostats are may be used bare, may be formed into coils, or may be cast sometimes used to de-energize the heaters if the heater tem- 231 232 CHAPTER 17 1959 Guide Table 1 .... Principal Types of Electric provide a secondary air passage promoting circulation and Space Heating Systems minimizing rear casing temperature. Depending on details . of unit construction, the convection heat delivery constitutes A. Radiators, Convectors, Uoit Heaters--Built-In and Port between 40 and 70 percent of total output, with the remainder able dissipated into the room as radiant heat. . 1. Metallic resistor, high or low temperature Ratings usually, are from 1000 to 8000 watts (3400 to 2. Unit ventilator . - 27,300 Btu per hr) with some models down to 500 and up to 3. Baseboard-type resistor 15,000 watts. Voltages are the standardized values of 120, 4. Resistor with fan, including unit heater 208, and 240. Similar models equipped with air circulation 5. Resistor unit placed in room-type air conditioner . fans are available, giving convection heat delivery up to 90 6. Resistor with focusing radiation reflector . ' ' percent. Other types, using similar components but without 7. Steam radiator with immersion electric element' ' a fan, are arranged as floor furnaces to be installed between 8. Floor furnaces floor joists. A manual switch and thermostat integral with the B. Panel-Type Installations ' ' ... unit are usually provided. 1. Ceiling panel The location of electric convectors should be governed by a. Rigid composite panels containing electrically con the same principles that determine arrangement of steam or ductive rubber ' b. Flexible composite sheets containing embedded metallic filaments or conductive rubber ' hot water convectors with respect to air movement. - Small portable units are available with ratings up to 1650 watts for operation at 120 volts. Higher wattage units are c. Electric conductors embedded in plaster on lath made for 208 or 240. volt application, and require suitable d. Electric conductors embedded in plaster or similar heavy duty receptacles. material between two layers of plaster board 2. Wall panel ' Unit Ventilators a. Rigid panels, as for ceilings ' b. Flexible sheets, as for ceilings 3. Floor panel a. Electric conductors embedded in concrete slab G. Central Hot Water Systems 1. Water from electric heater pumped to radiators or'con- vectors'in rooms '' 2. Same, with thermal storage for off-peak operation 3. Fuel-fired boiler converted to electricity ' ' 4. Heat pump systems--See Chapter 39 ' D. Central Warm Air Systems . - * ' 1. Resistance-element bank in housing or air duct 2. Fuel-fired furnace converted to electricity 3. Heat pump systems--See Chapter 39 ': - Unit ventilators with electric heating elements of the metal sheath type with extended surface are used to provide heat ing and ventilating of.school classrooms. Overheat switches are usually provided for each element in the heating section to de-energize the elements in case of interrupted fan opera tion. Ratings are available up to 30 kw in the larger sizes of units. Auditorium unit ventilators of the same type are rated up to 300 kw. The total capacity of the unit ventilator is made up by numerous smaller heating elements so tempera ture control can be accomplished by energizing or de-energiz ing the elements one at a time. The application of unit venti lators is described in Chapter 15, Unit Ventilators and Unit Heaters. Unit Heaters ' peratures become excessive for any reason such as a reduction in-air flow. Heaters must be de-energized on fan shutdown. (See.Chapter 43 for general information on controls.) . . TYPES OF ELECTRIC SPACE-HEATING SYSTEMS The inherent adaptability of electric energy for transmis sion, conversion, and regulation, and the relatively high unit cost in terms of thermal equivalent, as compared with fuels traditionally used for space heating, necessitates and justifies greater attention to efficient utilization. ' " ' Types of electric heating equipment and complete heating systems in current use are listed in Table 1. The sequence shown is for convenient reference only, and does not indicate the relative extent of use, quality of performance, or installa tion cost and operating expense. Installations of all types listed are in successful operation, but performance and cost depend in large measure on proper application to the local conditions. EQUIPMENT AND INSTALLATION METHODS Convector with Metallic Resistors - Heating units for wall mounting, recessed orsurface type, are made with resistors of incandescent hare wire'or'lower temperature bare wire'or sheathed elemental'An inner liner or reflector is usually placed-between resistors and c-asing to Electric unit heaters include a.suitable built-in fan which circulates room air over heating elements; they are employed for the same uses as other forms of unit heaters (steam, hot water, gas, oil), if conditions are favorable to electric heating. They are especially adaptable for supplemental heating, for small occupied rooms in otherwise unheated buildings and for unattended equipment enclosures in which temperature must be maintained above freezing. Location and arrangement of such unit beaters are discussed in Chapter 15. - Baseboard-Type Unit Metal casing proportioned to resemble and replace con ventional baseboard.along walls contains one or more re sistors placed horizontally. These should be rated from 80 to 250 watts (270 to 850 Btuh) per linear foot of baseboard unit. Resistors may be bare wire, sheathed element, <ast grid, finned, or ceramic extended surface. The vertical dimension is usually 4 to 9 in. and projection from face of wall from V/i to ZVt in. Location follows the same principles applying to hot water type baseboard installation described in Chapter 14. The maximum surface temperature of the housing should be limited to 190 F. ` .' Baseboard-type units using glass panels 6 to 8.inches high and 30 to 42 inches long' are available for operation at maxi mum surface temperature limited to 250 F. . Large high-wattage unit-type heaters are available for ceiling or high wall mounting. These are similar to steam Electric Heating 233 and hot water unit heaters in appearance and function. Re sistors may be placed in room air conditioners to permit operation as forced air heaters when desired. Resistor Portable Heater with Focusing Reflector An example of the focusing-reflector-type heater is the parabolic or circular bowl having, in its center, an incandes cent wire coil resistor on a ceramic core, often screwed into a porcelain or other approved type receptacle. Usual ratings are 500 to 1650 watts for 120 volt use. Heat emitted is 75 to 85 percent radiant. Sectional focusing-trough-type reflectors are made with low temperature resistors or with quartz lamps to be sus pended from the ceiling or bracketed from the wall. Rated capacities are 200 to 1500 watts per linear foot of unit. In stallations of this kind are usually to handle the perimeter heat loss. In a modified form, similar units are employed for infra-red heating and drying in industrial processes. Steam Radiator with Immersion Element Radiators equipped with an immersion element screwed into a bottom opening, are usually sealed after charging with water and antifreeze compound. A safety valve or thermal relief plug is provided to protect against excessive pressure - and temperature in case heat dissipation is unduly curtailed by obstructions to air convection. The stcam-and-water inter mediate heat transfer does not affect overall thermal effi ciency, but gives the unit operating characteristics adapted for certain applications. Units may be permanently connected by conduit, or used as portable heaters with cords. . Ceiling-Panel Installations with Conductive Rubber Panels of laminated construction containing electrically conductive rubber, with rating of 22 watts (75 Btu) per sq ft, for 115 and 230 volt service, are built in standard sizes 3 x 4 ft, 4 x 4 ft, and 4 x 6 ft. They consist of a layer of special rubber about ki* in. thick sealed between layers of phenolic resin-impregnated electrical insulating paper. The assembly is covered on each side with a sheet of aluminum foil. Overall thickness is K# in.; weight is 0.4 lb per sq ft. Metal strips embedded along edges of the rubber sheet serve as potential leads. Electric terminal blocks are provided on each panel and standard raceway moldings are furnished for wiring con nections. An earlier type of construction using asbestos-board backing to form rigid panels Vf in. thick has been discon tinued. Under normal operating conditions, the surface tempera ture of an automatically controlled fifing panel is about 100 F. When panels are turned on in a cold room or with continuous operation, the maximum temperature reached is 120 F. , Since it is not permissible to cut heating panels, the entire pattern for ceiling must be planned in advance, with particu lar attention to coverage near exposed walls. Attachment to smooth surfaces may be made by a special adhesive applied on the ceiling along a i Vi in. fastening margin provided around the four sides of each panel. A highly sensitive room . thermostat with.narrow operating differential should be used in each room. - Ceiling-Panel Installations with Embedded Con- ' doctors Resistors or cables for embedding in ceilings to form panel heating installations are electrically insulated with coverings resistant to high temperature, water absorption, aging effects, and chemical action with plaster, cement, and soil- Cable units identified by a color code are furnished in nominal standard lengths from about 75 to about 1800 ft, and are rated from 200 to 5000 watts for standardized voltages of 120 or 240. The outside diameter of the cables is usually about Vs in. Non-heating leads 7 ft long are attached to each unit to con nect at thermostat or connection box without running cable beyond the ceiling. The length of cable or leads must not be altered. The identification label showing rating may not be removed. Manufacturer's instructions should be followed regarding installation procedures. The lath used is of non-metailic fire-resistant type. The cable is secured to the lath with staples spaced not over 16 in. apart. Each cable is tested after fastening on lath, and after first plaster coat has been applied, for continuity of circuit and for insulation resistance of at least 100,000 ohms measured to ground. The minimum spacing between cable passes is 1^4 in. and is generally used near cold walls, with up to double that spacing near interior areas of the room. Non-heating leads outside the ceiling should be installed by approved wiring methods. Cables must be kept away from metallic materials and from areas of ceiling additionally heated by recessed or surface mounted lighting fixtures. All general power and light wires should be run above thermal insulation or at least 2 in. above the heated ceiling surface. For plastered ceilings, non-insulating plaster is applied in two or three coats with the first coat troweled in the same di rection in which the cable runs. Ceiling cables, properly engi neered, installed, and operated will not cause ceiling cracks. While new plaster is drying out, the system should not be energized and the range and rate of temperature change should be kept low by other heat sources or by ventilation until plaster is thoroughly cured. The use of vermiculite or other insulating plaster is contrary to code provisions since it causes cables to overheat. For laminated filing construction, cables are stapled to non-metallic lath as for plaster, and then a second layer of non-insulating ceiling board is applied with a layer at least Vs in. of plaster or similar compound to sandwich the cable firmly in place and improve heat , transfer. A highly sensitive room thermostat with narrow operating differential is recommended for each room. Chapter 30 in cludes data on panel heating with electric panels. Electric Wall Panels Cable embedded in walls similar to ceiling construction is occasionally found in Europe. Because of possibility of dam age due to nails driven for hanging pictures or from building alteration, most codes prohibit such panels in the United States. Interference with radiation caused by furniture place ment and interior decorations reduce the desirability of wall panels. Radiant Convector Wall Pane! Glass electric heating units, sometimes designated as ra diant panels, depend on the heating effect produced by pas sage of current through a thin coating of conductive material fused to one face of a panel of V* -in. thick special glass. The conductive layer may be sprayed-on aluminum or printed metallic oxide patterned to form a grid several thousandths of an inch thick, or fused-on material to give a uniform coat ing less than 0.0001 in. thick over the entire active face of panel. Normal glass operating temperatures are 300 to 400 F, with maiimiim permissible temperature around 650 F. Electric wiring connections are made by a variety of means 234 CHAPTER 17 1959 Guide to the panel, with leads provided for easy field connection. The panel is supported on insulators within a metal frame, with a reflector behind the glass arranged to provide space for air circulation. Protective guards are usually provided to re duce hazards to a minimum. Glass units are usually rated between 600 and 3000 watts, for standardized voltages of 120, 208, or 240 volts. Starting current for some types exceeds normalized current by 10 to 50 percent. However, there are types with substantially no current surge. Frame sizes vary from about 30 x 24 in. for 1000 watt size to 42 x 6 in. for baseboard models, and are arranged for recessed or for surface mounting. Thermostats integral with the unit are optional. Portable units with cord are available. Radiant panels using tubular elements built or cast into extended aluminum panels have emissivity characteristics similar to gls panels. Electric Floor Panels Resistor cables of the same type used for ceilings are used for floor panel systems in concrete slabs. Precautions to be observed in construction of slabs for panel heating are cov ered in Chapter 12 and 30. Non-insulating cement finish 1% in. thick is poured and troweled above cables fixed to a mini mum 3 in. slab. In some areas, cables may be stapled to wood nailing strips fixed in the surface of the rough slab. When the slab is made of light-weight insulating concrete, cables may be stapled directly to the slab. Alternative special anchors are available to hold the cable at proper spacing during pouring, and are held by nails driven by hand or powder impact driv ers. Otherwise, periodic temporary fastening with daubs of cement, plaster of Paris, strips of masking tape, or other nonconductive material must be used. With monolithic finish, nailing strips are omitted and the cable is strung on frames with-nail spacers; frames are re moved when enough concrete has been poured to hold the cable in place. If desired, magnesite flooring, ceramic tile flooring, asphalt tile, or wall to wall carpeting may be used on the floor. Insulating-type concrete may be used below cable, but must not be used around or over cable. Central Hot Water Systems Heating systems of hot water type using radiators or con vectors, discussed in Chapter 28, may be operated using an electric hot water boiler containing immersion elements (re sistors) . Resistors may be interlocked to prevent energizing when the circulating pump is not operating. The boiler wa ter holding capacity should be sufficient to minimize cycling. For off-peak operation where electric rate considerations justify, a water heating tank of large storage capacity may be employed. The system may be designed for a water tem perature of 250 to 275 F at pressures up to 75 psig, with suitable piping systems for this pressure. An automatic valve may provide 140 to 160 F water at the pump by mixing hot water from the tank with cooler water from the return main. Another method employs the flash principle, withdrawing water at high storage temperature into a low-pressure sepa rating chamber where steam is obtained as a result of the pressure reduction; however, power for pumping is substan tially greater with this steam-accumulator method. Thermal insulation on boiler tank and piping must be adequate to minimize losses. High investment, space required for equip-, meat, and loss of much of the convenience and economy of operation available with other forms of electric heat, tend to limit the application of this type of system. Central Warm Air Systems Systems employing resistors mounted in a frame or hous ing may be fitted into ducts with a fan forcing the air to the various spaces to be heated, or may replace the heat ex changer of fuel-fired furnaces to convert them to electrical operation. Much of the convenience and economy of opera tion available with electric heat is lost by such central system applications. Heat Pump Systems Heat pump systems are discussed in Chapter 39. Heat pump systems using air as a heat source lose capacity rapidly as the outdoor temperatures decrease, while water and earth heat source pumps sized for cooling also frequently reach the balance -paint at outdoor temperatures above outdoor de sign. Deficiency at temperatures below the balance point can be supplied by supplementary electric resistance ele ments. When these supplemental heaters are placed in in dividual spaces rather than centrally, the electrical demand is minimized, the individual spaces may be maintained at slightly different temperatures, and local reheat during the cooling cycle is readily available. An alternative provision for cold weather peaks is thermal storage in chemical salts and by other devices. Such processes are still in the development stage. The installed cost of residential heat-pump systems is higher than that of resistance types. Resistance heating sys tems, except the minority using air circulation through ducts, do not lend themselves to consolidation with summer air conditioning. Use with an independent cooling installation may be preferable and attained with lower investment cost. CALCULATING CAPACITIES The procedure outlined in Chapter 12 for calculating the heating load may be used for electric systems. Load expressed in Btu per hour is converted to kilowatts by the divisor 3413 Btu per kilowatt. The National Electrical Manufacturers Association has published the NEMA Manual for Electric House Heating describing methods and giving heat loss fac tors for calculating load directly in kilowatts. All the energy applied to a resistor transforms itself into heat, unaffected by temperatures of the surrounding air and of surfaces re ceiving radiated heat. However, both electric power input and heat output are directly affected by voltage at the re sistor terminals, being proportional to square of the voltage. Thus, a resistor rated 1000 watts at 240 volts, if used on a circuit at 220 volts, delivers 840 watts or 16 percent under the rated value, while at 208 volts the shortage is 25 percent. The arbitrary addition of a percentage safety margin on the calculated heating load is not recommended. Such prac tice would increase the peak electric demand and often the cost of electric service. ' The most economical electric heating systems from an operating standpoint are of decentralized type, with a ther mostat provided on each unit or for each room. This permits each room to compensate for heat contributed by auxiliary sources such as sunshine, lighting, and appliances. This ar rangement also gives a better diversity of the power demand due to non-coincidence of electric load from all units of an installation. Manual switches are often provided to permit cutting off heat or reducing temperature in rooms when not in use. When such operation is practiced, consideration should be given to provide adequate capacity for warm-up as com pared to a system maintaining a constant temperature. Electric Heating For wftkft of economy buildings intended to be heated electrically should be well constructed, have adequate ther mal insulation and storm windows or double-glazed windows in more severe to minimize heat loss and weather stripping to minimize, infiltration. The relatively high electric cost for thermal energy, about $5.40 per million Btu at $0,018 per kwhr, for example, as compared with about $1.50 for oil at $0.16 per gal when utilized with 70 percent efficiency, gives economic justification for substantial expenditure to reduce heat consumption. The large majority of dwellings heated economically by electricity have heat factors (quotient of Bftftflnnal energy consumption in kilowatt hours, divided by degree days and by volume of gross heated space expressed in thousands of cubic feet) between 0.15 and 0.3. The features necessary to hold consumption within these limits result in construction that for 5000 degree-day climate with 0 F out door design temperature, gives a calculated heating load of 3400 to 5100 Btu per hr per 1000 cu ft grass volume. Heat factors up to 0.4 are not uncommon, but experience shows that such high heat requirement may result in excessive op erating cost. General practice is to provide adequate thermal insulation with electric heating installations. POWER CONSIDERATIONS Rales for Electric Service The cost of electricity varies due to several factors. The main elements are the annual charges, including taxes, on capital invested and those expenses necessary to keep the electric utility system at all times in a state of readiness to serve the load. The cost of generating the energy is secondary. Electricity is not stored, but must be produced, instantane ously when and as required by the user. Consequently, the time of power use, both daily and seasonally, and relation between rate-of-use or demand and the energy consumed within a period (load factor) have large effects on costs and the rates charged. Special low rates sometimes are available during certain prescribed off-peak hours of use, when the system load is low. Space heating is a load whose magnitude is determined basically by weather, and is affected to a' much lesser extent by the electric customer'6 use of his premises. Most of the heating loads in a region occur simultaneously, thereby tend ing to create peaks for which the capacity of the electric sys tem must be adequate. Accordingly, rates contain, in one way or another, charges both for demand and energy. Demand may be indicated directly by a demand meter or be derived from manufacturers' rating data shown on nameplates of the heating equipment. In block?type rates, where demand is not specifically mentioned, it is in part reflected by higher charges per kilowatt-hour in the earlier blocks. Control of Electric Demand To obtain electricity for space heating at minimum cost, it is necessary to keep the user's kilowatt demand as low as possible, by provisions in original design of the installation and by judicious methods of operation. Excess heating ca pacity should be avoided, but without jeopardizing satis factory performance in cold weather. A variety of control methods can be applied to minimize both demand and con sumption. Decentralized control with a thermostat in each room or on each heating unit, together with manual switch to cut off any unoccupied room, is one method. Sequence switch ing whereby electric service to individual rooms or circuits is shifted in rotation by an automatic timing device and se 235 quence is modified by outdoor thermostat or by total electric load, is another. Load-limiting controls of several types have come into use. These are generally arranged to measure the customer's total power demand, which for a residence may be grouped as lighting and miscellaneous appliances, refrigerator and water heater, cooking range, and the space heating system. When the demand exceeds a preset value, one or more heat ing circuits are cut off progressively in rooms least affected by the interruption. Experience shows that with electric floor or ceiling panel heating, temperature drop occurs slowly, at the rate of about 1 deg per hour for concrete slabs and 2 deg for plaster construction or rigid panels properly backed with thermal insulation. Moreover, electricity consumed by lighting, appliances, and cooking ranges is contributing some useful heat at such times. Another form of limiting control for 120/240-volt 3-wire circuits provides complete or sequence transfer of space heating units from 240 volts to 120 volts, thereby reducing the electric input to one quarter whenever the total load oi general-service component exceeds a preset limit. This method lends itself to use of an outdoor thermostat actuating a relay, whereby in mild weather the entire heating system operates at 120 volts and with lengthened cycles obtains more uniform room temperature. For reducing temperature at night, if de sired, a clock-operated master thermostat can be provided to lower the heating-system voltage. On some electric utility systems, centralized control by means of a pilot-wire or car rier-current actuating a relay is applied to house-heating in stallations: With any type of control, time-delay relays should be used in order that upon restoration after an emergency service interruption or whenever a master thermostat calls for heat, the individual circuit or units will come on non-simultaneously over a period of a few minutes. This is advisable espe cially for types of resistor units that have a power input, when cold, as much as 50 percent above the rated value at normal operating temperature. Operating Costs With increased numbers of electric heating installations, operating cost estimates and experience records are accumu lating. Experience records are indicating that actual con sumption may be less than conventional calculations and comparisons would indicate. This is particularly true with thoroughly insulated structures or for applications having short hours of maintained temperatures and long reduced temperature periods. The NEMA Manual for Electric House Heating applies the following formula for estimating the cost of electric heat ing: A..n..n...u..a..]...k..i.l.o..w...a...t.t.-..hour consump.t.ion " H----L--X-- --DD---X---C--- where C " constant (see text below). HL = heat loss of building, kilowatts. DD *= annual degree days for area. TD " difference between indoor and outdoor design tem perature, Fahrenheit. The constant C depends on a number of variables such as weather conditions in the locality, orientation, design and construction of the building, living habits of the occupants, 236 CHAPTER 17 1959 Guide Table 2 .... Relation of Resistor Voltage to Heat Delivery Condition Volt* Hoot Detfverod % Electric system, nominal value.................. For design of equipment, at terminals -- Range, as basis for design Minimum..................................................... Maximum..................................................... On secondary distribution system Favorable zone, as to voltage conditions Minimum.........:...................................... Maximum................................................. Tolerable zone Mioimum................................................. Maximum................................................. Emergency conditions.................................. 120/240 118/236 110/220 124/248 110/220 125/250 107/214 127/254 90/180 103.3 100 86.8 110.5 86.8 112.0 82.2 116.8 58.3 design of heating system, and internal sources of heat. Ex perience with many thousands of electric heating installations has shown that a conservative value for C is 18.5. Values of C as low as 12 have been reported on individual installations. It is recommended that a value of C of 18.5 be used unless local experience of a statistical nature has established a more re liable value for the particular area concerned in the estimate. For block-type electric rates, multiplying the annual kilo watt-hour energy consumption by the cost per kilowatt-hour indicates the annual cost. For demand rates, the assistance of the local utility company should be secured to estimate de mand and energy uses by the month on the particular rate involved. It may be pointed out that residences with thermo static control tn each room generally establish a maximum of 75 percent of the total calculated heat load as the highest demand requirement for heating. Voltage Requirements The preferred nominal system voltage at point of electric . utilization by equipment, for single-phase 3-wire systems nec essary with space heating, is 120/240 volts, as stipulated by standards of the electrical industry (EEl Publication R-6 and NEMA Publication No. 117 issued May 1949). For * household heating appliances mentioned in the standards, such as air heaters, water heaters, and cooking ranges, the equipment voltage rating for design is specified as 118/236 volts, and the range of voltages to be used as a basis of design extends from 110/220 minimum to 124/248 maximum. How ever, natural variations exist from time to time in the condi tions at different points in any secondary distribution system and will affect both voltage level and range of fluctuations. Under emergency conditions on electricity supply systems, voltages of the order of 90/180 may be encountered. Heat delivery by resistors with these voltage values, expressed in percent of rated delivery with the normal 118/236 volts (at terminals) is given in Table 2. Voltages stipulated for secondary distribution systems are at point of service entrance to the building; the drop of vol tage in the house supply wiring to terminals of the heating equipment may be 2 to 3 percent, thus reducing heat delivery by some 5 to 8 percentage points below the favorable zone and tolerable zone values included in the last column of Table 2. Accordingly, it is necessary the designers of electric heating installations obtain specific information from the local electric utility company on both existing and anticipated future conditions at the location, before specifying the capac ity and voltage for equipment, wiring, and controls. BIBLIOGRAPHY W. F. Friend: Electric house heating--load characteristics and economics (Midwest Power Conference Proceedings, April 1951). E. E. Parks: Electric house heating (Electrical Engineering, August 1951). Electric House Heating (Rural Electrification Administra tion Bulletin 142-1, December 1957). F. A. Compton: Complete Electric House Heating (Edison Electric Institute Bulletin, May 1950). C- E. Simpson: House heating experience (Electrical World, October 9, 1948). B. H. Martin and T. W. Newberry: Heating by electricity in Tennessee valley area (Heating and Ventilating, May 1948). H. G. Kelsey: Longview house heating data (Electrical West, September 1945). . W. B. Morrison: Electric storage heating serves hew Oregon school (ffeatinp, Piping and Air Conditioning, June 1949). R. E. Sinclair: Electric house beating load characteristics (Electrical West, September 1950). . J. B. Cochran: House heating load characteristics as they affect wiring costs (Electrical World, April 12,1947). H. C. Bender: Heat factor formula to calculate electric house heating (Electrical World, May 12, 1945). W. F. Friend: Modulating and load-limiting controls for electric house heating (American Power Conference Proceed ings, March 1953, and Heating and Ventilating, August 1953, p. . 82). Methods developed for built-in radiant heat (Electrical West, December 1948). R. J. Lorenzi and J. F. Schreiber: Performance of electrical L. N. Roberson: Radiant heating by electricity (Heating and Ventilating, September 1946, p. 89). . .j R. S. Tice: Low-voltage high-current radiant heat (Electrical West, December 1947). .' Applications of radiant energy (Illuminating Engineering Society, Lighting Handbook, 1952, 8ection 18). hadianl Glass Heating Panels (National Bureau of Standards, Technical News Bulletin, May 1953). ' P. R. Achenbach: Radiant glam heating panels (Heating and Ventilating, January 1953, p. 83). . BE1-NEMA Preferred Voltage Ratings for A-C Systems and Equipment (Edison Electric Institute Publication No. R-6, May 1949, and National Electrical Manufacturers Association Publi cation No. 11, May 1949). Standard Handbook for Electrical Engineers (McGraw-Hill . Book Co., New York, 1952). R. E. Sinclair: Short method for estimating electric house heating load (Air Conditioning, Heating and Ventilating, Janu ary 1955). R. L. Boyd: Heat schools electrically? (Heating, Piping and Air Conditioning, December 1956). NEMA Manual for Electric House Heating (National Elec trical Manufacturers Association, June 1957). J. C. Beckett: Cost comparison: resistance space heating vs fuel-fired systems (Electrical Construction and Maintenance, October 1956). Space heating: what happens in the 6,000 degree-day zone (Electrical World, March 19, 1956). . W. R. New: Serving the ail-electric home (Electrical World, March 19, 1956). R. L. Boyd: It's here...the all electric school (Electrical Construction and Maintenance, February 1957). Handbook of Electrical Applications (Edison Electric Insti tute). . . W. J. Novak: Electricity and combustible fuels (Electrical Construction and Maintenance, April 1957). CHAPTER 18 WARM AIR HEATING SYSTEMS Forced Warm Air Systems; Air Distribution; Supply Outlets and Return Grilles; Duct Construction; Simplified Methods of Design for Perimeter Systems of loop, Radial, and Extended-Plenum Types; Return Duct System for Perimeter Installations,- Inside Wall Delivery Systems; Design of Large Systems; Automatic ControlsAdjustment of System,- Warm Air Ceiling Panel Systems; Summer Operation; Gravity Warm Air Systems ARM air heating systems may be conveniently di posed walls and glass.-A second method is to locate the sup Wvided into two classifications depending upon the ply openings near the floor,.or high in the side wall, on the manner in which the motive power for circulating the warimnside wall, and the return openings near the greatest outside air is supplied. In gravity systems, the motive head is due exposure. A third method is to locate all supply openings to the difference in weight between the heated air leaving around the outside wall, near the source of the greatest heat the top of the furnace nasing and the cooler return air en loss, usually beneath the windows, and to use grilles de tering the bottom of the casing. In a forced warm air heating signed to blanket the cold area. This causes mixing of the system, all or part of the motive head is supplied by a fan. warm air delivered with the cool air from the heat loss area Although' a great many gravity warm air heating systems and the cold air from infiltration, thus effectively prevent are in use, only a limited number of new gravity installations' ing drafts. It has been called perimeter heating. are now being made. Emphasis will therefore be placed upon In any case, the warm air registers should be so located and the design and installation of forced warm air heating sys so designed that the air stream never discharges directly tems. against people at rest. Tests* in Warm Air Research Resi dences No. 1 and No. 2 at the University of Illinois, have FORCED WARM AIR SYSTEMS indicated that nearly continuous blower operation gave bet In forced warm air heating systems, the air circulation is effected by motor-driven centrifugal fans, commonly referred to as blowers. The advantages of forced air systems are: ter results than intermittent operation. This type, of^opera tion is more commonly achieved by suitable adjustments of air quantity and - fan switch settings. than by continuous, operation of the blower* ' .. 1. The furnace may be placed in any part of the structure. - 2. Distribution ducts can be made email enough to be in conspicuous and out of the way, or be completely concealed from view where desired. 3. Circulation of air is positive, and in a properly designed system, can be controlled in such a way as to give a comfortably uniform temperature distribution. Supply Outlets and Return Grilles .. The type of supply outlet that should be used depends upon the type of distribution system to which it is applied. With perimeter duct systems, the supply outlets are usu ally located in the floor, in the baseboard, or low in the 4. Humidity control is readily attained. side-wall and underneath a window. In order to be most ef 5. The'air may be cleaned by filters or other means. fective, perimeter diffusers must deliver the air upward and 6. If properly designed or suitably adapted, the same air distribution system can be used for summer cooling as for winter heating. . 7. The'use of the fan permits flexibility in the location of supply and return grilles as required to obtain proper distribu tion of air for comfort. . 8. Ventilation air may be positively introduced and con ditioned. in a fan-shaped pattern so as to blanket the window or cold wall with warm air, thus mixing with and tempering the cold air which usually descends along a cold surface. Fur thermore, since delivery of the air outward into the room, rather than upward, is likely to impinge upon the occupants it should be avoided. With certain types of perimeter dif fusers, the air velocity at the diffuser face is limited only by The construction features of forced warm air furnace units and the function and selection of the various parts of a system are discussed in Chapter 35 and other publications.1 the pressure available at the diffuser and the noise charac teristics of the outlet. - Tests with inside wall supply systems conducted in Warm Air Heating Research Residence No. 1 have indicated that AIR DISTRIBUTION comparable results are obtainable with either high side-wall or baseboard registers, if proper registers and air velocities The conditions of comfort obtained in a room are influ enced greatly by the type of supply outlet used, and the are selected. Baseboard registers should be of a deflecting-diffuser type locations of the supply outlets and return grilles. In general that will direct the air downward toward the floor and dif it has been found that changes in the type, air velocity, and fuse it at the 6ame.time.' For baseboard registers, air veloci location of the supply outlet affect the room conditions much ties over 500 fpm should be avoided as they may cause dis ' more than the changes in the location of the return grilles. comfort. . Three methods of locating outlets and grilles are in common High side-wall registers should be of a type that will de use. One method is to locate the supply register near the liver the air horizontally or in a slightly downward direc floor so that the warm air from the register blankets a cold ' tion, and should be so located as to avoid impingement of wall, and mixes with the cold air descending from the ex air on ceiling or wall. Directional flow diffusing type regis- 237 238 CHAPTER 18 1959 Guide Warm Air Heating Systems 239 * tegtctere * to dawcf sir opword dong the m9 at e* wide on angle o* pCBSbk. Fig. 1-------Recommended Type of Floor or Low Side-wall .' Installation on Outside Wall* ters should be used to insure best results. Register air veloci ties should be such that the air velocity will be about 50 fpm three-quarters of the distance from the register to the opposite wall. Velocities through registers may be reduced by the use of registers larger than the connecting ducts. Diffusers should be used to spread the air uniformly over the register face. Basic rules for the location and selection of registers, to gether with explanations of factors affecting operation, are given in Section 6 of Manual 4, Sections 3 and 4 of Manual 10, or Section B of Manual 7, published by the National Warm Air Heating and Air Conditioning Association.*' * * Registers should be well proportioned and decorated to harmonise with the. trim. Air supply registers should be Fig. 3.... Recommended Type of Baseboard and Low Side-wall Installation on Warm Wall* equipped with dampers, and all registers should be sealed against leakage around edges. The register types shown in Figs. 1, 2, and 3 have been recommended as standard by the National Warm Air Heating and Air Conditioning Associa tion. Return-air grilles may be located in hallways, near en trance doors, under windows, in exposed comers, or inside walls, depending on location of supply outlets. Baseboard re turns are preferable to floor grilles. It is usually considered desirable to have them located in or near outside walls when supply outlets are located on inside walls. With frhH type of system, it is desirable to locate return grilles in as many rooms as possible. When used in perimeter systems, the re turn grilles may be centrally located. In basementiess struc- Table 1 .... Recommended Thickness for Duct Materials Diomefer, In. Miman/a Thkknost US. Gog* AJvrmmi 64S Gog* Mcnlaaina Weight of Tia-Plate Less than 12 12 or more 30 28 26 IC (107 lb) 26 IX (135 lb) * Horixootaf vane*, in bock or front, fa giv* downward defections not to excotd tro 15 to 22 deg. Fig. 2.... Recommended Type of High Side-wail In stallation on Warm Wall* Width, to. 14 or less Over 14 Mminnm Thhkmts Galr. Iron, US. Gogo AJvmiaom SSS Gog* Minimum Weight of Tin-Plate Duets Enclosed in Partitions I 30 I 26 I IC (107 lb) 28 28- IX (135 lb) Ducts No* Enclosed in Partitions Less than 14 I 28 I 26 I 14 or more 28 24 -- -- Note: The Ubl* above a is xccardxnoe with the requirement! of tbe National Board of Fin Underwrite!* to provide adequate fire protection. Industry practice tt to use heavier cafe metals where maximum duct widths 24 in. Fig. 4.... Perimeter-Loop System with Feeder and Loop Ducts in Concrete Slab ' . fig. 6.... Perimeter-Radial System with Feeder Ducts in Concrete Slob or Crowd Space tures, it is usually convenient to locate the return openings either high in the wall or in the ceiling. So far as the heating is concerned, however, this is merely a matter of conven ience because low returns have been found to work equally well. It is usually not recommended in residential systems that any one return serve an area having a heat loss of more than 60,000 Btuh. Dampers Suitable dampers for air direction or volume control are essential to any duct system. Special care must be used in the design of any system, to minimize resistance. Sharp elbows, angles, and offsets should be avoided. Three types of damp ers are commonly used. Volume dampers are-used to com pletely cut off or reduce the flow through ducts. Splitter dampers are used where a branch is taken off a main trunk. Squeeze dampers are used for adjusting tbe volume of air flow and resistance through a given duct. A damper with.-positive locking device should be provided for each main' or duct branch. Labels placed on ducts should indicate the room being served. Damper positions should be marked to indicate proper summer and winter settings, and to reveal tampering. DUCT CONSTRUCTION Tbe ducts may be either round or rectangular in cross section. The centerline radii of elbows should preferably be not less than one and one-half times tbe pipe diameter for round pipes. The throat radius of a turn in a rectangular .duct should be at least one-half the duct dimension in the ptn-nfr of the turn. Warm air ducts passing through cold spaces or located in exposed walls, should have 1 to 2 in. of insulation. . Ductwork must be permanent, rigid, non-buckling, and non-rattling. Joints in ductwork should be airtight: Gal- vanized-iron or aluminum `sheet are usually used in the construction..of. ducts, but other materials may be used under the proper circumstances. Ail return ductwork within six feet of the winter air conditioner shall be of noncom bustible material. a Requirbments of the National Board of Fire Underwriters state that heating supply ducts shall be constructed en tirely-of noncombustible material equivalent in structural strength and durability to the specifications in Table 1. Supply ducts must be securely supported by metal hang ers, straps, lugs, or brackets. No njtils should be driven through duct wails and no unnecessary holes.should be cut in them. ; j;. ' >-.* . Supply air stacks should not be installed'in outside walls pnlftss it. ^impracticable to do otherwise. If it'is necessary to do this, the' stack must be effectively insulated against exposure. ^Failure-to do this will-materially reduce the heat ing or cooling capacity of the branch duct and will probably result in unsatisfactory comfort conditions in the room. No supply air duct should come in contact with masonry walls. All supply ducts which pass through a masonry wall should be covered with at least Yi in. of insulation where they pass through the wall. All supply ducts or outlets should be equipped with an adjustable, locking type damper, for air volume control. The damper should be installed in the branch duct whenever it The aatiantm thkknon of conerate over fho loop duef thoold be 2$^ m. and continuous mesh mnforcfng nof test then 6 x 0-10 gage and 16 in. wide rhotM be placed in the concrete and centered over (he duct. Fig. 5.... Cross-Section of Slab Construction Contain ing Perimeter Duct1 Table 2.... Diameter of Feeders in Perimeter-Loop System length of fwdir la F**f Up to 7,999 8,000 to 8,999 9,000 to 10,999 11,000 to 11,999 12,000 to 12,999 13,000 to 17,000 0-15 fW Indie* 6 6 7 7 7 8 16-30 F**t Incise! C 7 7 8 8 8 240 CHAPTER 18 1959 Guide is accessible. Splitter dampers for volume control are not Return systems having more than one return intake may be equipped with balancing dampers. This is particularly desirable with systems in which the supply outlets are lo cated on the inside wall or in the ceiling of the conditioned rooms. Special attention should be given to the problem of noise elimination. The metal duct connection to and from the furnace casing and fan housing should be broken by strips of fire resistant fabric. Motors and mountings must be care fully selected for quiet operation. Electrical conduit and water piping must not be fastened to, nor make contact with the fan housing. Installation of a fan directly under a return air grille is usually avoided. SIMPLIFIED METHODS OF DESIGN Simplified methods of design have been developed for sev eral types of forced warm air beating systems. In general, the specific procedure chosen depends upon the type of system and the type of structure in which it is to be used. In most cases, more than one type of system may be used in a specific structure. It is therefore necessary to first choose the system desired and then determine the applicable design procedure. Perimeter-Loop Systems in Concrete Slab Con struction The perimeter-loop system,* shown in Fig. 4, conveys the warm air through embedded ducts to perimeter diffusers. The air is delivered from the furnace to feeder ducts which extend radially to the loop duct. The air flows through the loop duct to the diffusers. The ducts serve the dual purpose of conveying the warm air and of warming the floor. Al though the design of the concrete slab is not specifically the concern of the mechanical engineer, it is absolutely necessary that he understand the considerations involved lest im proper construction be used with consequent adverse effect on the performance of the hearing system. For information on slab construction, as well as duct placement, duct insula tion, etc., see Manual 4 of the National Warm Air Heating and Air Conditioning Association.* A' section of typically in stalled loop duct is shown in Fig. 5. Simplified design procedures are contained in Manual 4. One of these procedures subject to the following limitations: total heat los 100,000 Btub, maximum perimeter 210 ft, and maximum length of uninsulated feeder duct 30 ft for area served by one furnace; is the following: 1. Calculate the beat loss for each room using the methods explained in Chapter 12. For subfloor and edge losses* see Manual 3 of the National Warm Air Heating and Air Con ditioning Association. 2. Determine the required furnace-bonnet capacity from the heat Iosb of the building. 3. Locate the diffusers on the plan. For best heating results, if a room has a heat loss of more than 8,000 Btuh or if it has two or more exposed walls, use two or more diffusers. Propor tion the Btuh heat loss of each room among all diffusers in that room. 4. Locate, the feeder ducts. First, divide the heat loss of the structure by 15,000 to determine the probable number of feeders. Second, locate the ducts so that they connect with the perimeter-loop at areas of greatest heat loss or in rooms where warm floors are particularly desirable. Third, locate the feeder ducts so that no more than 3 diffusers are in the section of loop duct between any two feeders. (The final number of feeder ducts may be larger than that originally estimated.) 5. Determine the size of feeder ducts using Table 2. Assume that the Btuh required by each diffuser will be supplied by the feeder nearest it. uetermine the feeder duct diameter from its length and the total diffuser Btuh delivery carried by it. ' . 6. Determine the total diffuser free area required in each room ng Table 3. Measure the length of feeder duct under each room. Add to this one-half of the length of the loop duct, and determine the total diffuser free area required. Apportion this among all diffusers in the room. , 7. The diameter of the loop duct should be uniform and equal to the diameter of the largest feeder duct. Perimeter-Radial Systems in Concrete Slab Con struction The perimeter-radial system, Fig. 6, is similar to the per imeter-loop system in that the supply ducts are embedded in the concrete slab. The feeder ducts of the radial system ex tend directly from the subfloor plenum to the perimeter dif fusers, and there is no loop duct around the perimeter of the floor. The feeders do provide floor-warming, but not to the same degree provided by the feeder and loop ducts of a perimeter-loop system. The same considerations of slab con struction and edge insulation apply to both systems. A simplified design procedure* using 6-in. diameter duct and subject to limitations of: 1,000 to 1,200 sq ft maximum area, not more than approximately 15 ft along perimeter between diffusers, and no radial duct substantially longer than 20 ft, is the following: 1. Calculate the heat loa of each room or area using the method explained in Chapter 12. For subfloor and edge losses, see* Manual 3 of the National Warm Air Heating and Air Conditioning Association. 2. Determine the required furnace-bonnet capacity from the heat loss of the building. 3. Locate the diffusers on the plan. Allow at least one dif fuser for each exposed wall in each room or area of the build ing and preferably beneath window areas. For residential in stallations, limit each diffuser to a maximum of 7,000 Btuh. This is a preliminary estimate of the number of diffusers needed. ' 4. Measure the length and count the number of elbows in eaeff feeder duct. Determine Btuh capacity of each feeder duct from Table 4. Use Table 4 (Section A) for side-wall and floor diffusers and Table 4 (Section B) for baseboard diffusers. 5. If the total Btuh capacity of ail feeders to each room or area equals or exceeds the heat loss of that room or area, the number of feeders initially chosen is satisfactory. If the heat loss exceeds the Btuh capacity of the feeders, use and locate additional diffusers and feeder ducts. 6. The cfm values in Table 4 are used for designing the return-duct system. Perimefer-Radlal System in Crawl Space or Base* ment Construction The perimeter concept of warm air heating has been ap plied to crawl-space and basement homes by locating the diffusers in the perimeter location and by warming the area underneath the floor of such structures. Although the con struction of the crawl space and the foundation wall is the responsibility of the architect and the general contractor, it is important that the engineer cheek the construction to make certain that it will not adversely affect the perform ance of the heating system. Details on crawl-space con struction are shown in Manual 4 of the National Warm Air Heating and Air Conditioning Association* The crawl space or basement should be heated to provide warm floors. A simplified design procedure* for an individual duct sys tem is summarized as follows: 1. Calculate the heat loss of each room or area using the Warm Air Heating Systems Table 3.... Minimum Diffuser Free Area Required for Perimeter-Loop Systems 241 Hoot loss of Room Stub 0 to 4,000 to 6,000 to 8,000 to 3,999 5,999 7,999 9,999 10,000 to 11,999 12,000 to 13,999 14,000 to 15,999 16,000 to 17,999 18.000 to 19,999 20,000 to 21,999 22,000 to 23,999 24,000 to 25,999 26,000 to 27,999 . 28,000 to 29,999 30,000 to 31,999 32,000 to 34,000 Length of feeder Duct under Room Plus length of Perimeter Dvcf Undsr Room, Ft. 0-9 Ft. 10-19 a 20-29 a 30-39 Ft. 40-49 Ft. 50-59 Ft. 60-59 a Total Diffuser Free Area Required for Room, Square Indies 20 32 27 23 18 43 39 34 29 25 20 55 50 45 41 36 32 27 66 61 57 52 48 . 43 38 77 72 68 63 59 - 54 60 88 84 79 75 70 66 61 100 95 91 86 82 77 72 111 106 102 97 93 88 84 122 118 113 109 104 100 95 134 129 125 120 116 111 106 145 140 136 131 127 122 118 156 151 - 147 142 138 ' ` 133 129 168 163 159 154 150 ' 145 141 179 174 170 165 161 156 152 190 185 182 176 173 167 164 Section B. Use this Table if length of Feeder which DeGvere Major Portloo of Warm Air to Room is from 10 to 20 Ft. 0 to 3,999 4,000 to 5,999 6,000 to 7,999 8,000 to 9,999 10,000 to 11,999 12,000 to-13,999 14,000 to 15,999 16,000 to 17,999 18,000 to 19,999 20,000 to 21,999 22,000 to 23,999 24,000 to 25,999 . 26,000 to 27,999 28,000 to 29,999 30,000 to 31,999 32,000 to 34,000 23 18 18 36 31 26 21 16 16 49 44 39 34 29 24 19 61 -- 56 51 - 46 41 36 31 73 68 63 58 53 48 43 86 81 76 71 66 61 50 99 94 89 84 79 74 69 111 106 ' 101 96 91 86 81 123 118 113 108 103 98 93 135 130 125 120 115 110 105 148 143 138 133 128 123 118 161 156 151 146 141 136 131 174 168 164 158 154 148 144 186 181 176 171 166 161 156 198 194 188 184 178 174 168 211 206 201 196 191 186 181 Section C Use Thb Table if length of Feeder which DeGvers Major Portion of Worm Air to Room b from 20 to 30 Ft. ' 0 to 3,999 4,000 to 5,999 6,000 to 7,999 8,000 to 9,999 10,000 to 11,999 12,000 to 13,999 14,000 to 15,999 16,000 to 17,999 18,000 to 19,999 . 20,000 to 21,999 22,000 to 23,999 ' 24,000 to 25,999 26,000 to 27,999 28,000 to 29,999 30,000 to 31,999 32,000 to 34,000 . 27 21 21 42 36 30 24 18 57 51 45 39 33 27 21 72 66 60 . 54 48 42 36 86 80 74 68 62 56 101 95 89 83 77 71 116 110 104 98 92 86 131 125 119 113 107 . 101 50 65 80 95 145 139 133 127 121 115 100 160 154 148 142 136 130 124 175 169 163 157 151 145 139 190 184 178 172 166 160 154 205 199 193 187 181 175 169 220 214 208 202 196 190 184 234 22S 222 216 210 204 198 249 243 237 231 225 219 213 > 1 | 242 CHAPTER 18 1959 Guide 'V ' ' ' .. ... Warm Air- Heating Systems ' . ' . ' i Table 4.... Btuh Capacities and CFM of 6-Inch Feeder Ducts in Perimeter-Radial Systems in Concrete Slab Floors Section A. For Side-Wad and Floor Diffuser* Bonnet Pram,, 0.15 in. Static Tanpcatu,, 170 P Table 5.... Btuh Capacities-and Cfm of Individual Ducts in Perimeter Systems Used in Crawl-Space or Basement Construction . Secfioa A. For 5-tnd> Individual Bound Pine and for S*do-wa8. Root, ood Baseboard Diffuser* . 243 '"!f \i | j [ No. of Shows Copodfy 0 Btuh Cfm 5 Actual length of Pipe from Bownf fo Diffuser--Feef - 10 IS 20 25 30 35 40 45 50 55 60 65 70 75 80 8700 8060 7460 6920 6430 5960 5550 127.7 124.8 122.3 119.7 117.4 115.0 113.0 No. of Shew] 0 Btuh Cfm Actual length of Pipe From Bonnet to Diffvser--Feet 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 8700 7900 7150 6450 5800 5230 4700 4230 3830 3470 3150 2860 2600 100.5 96.2 92.7 89.7 87.0 84.6 82.5 80.4 78.4 76.5 74.8 73.2 71.7 i; 1 Btuh am 2 Btuh Cfm 3 Btuh am 4 Btuh am 8620 8000 7430 6900 6400 5930 5500 5100 122.8 120.0 117.6 115.3 113.0 111.0 109.0 107.3 8600 7960 7390 6860 6380 5940 5530 5150 4800 118.5 116.2 114.0 112.0 110.0 107.8 106.0 104.5 103.0 8640 8020 7450 6950 6460 6020 5600 5200 4850 4500 114.0 112.0 110.0 108.2 106-5 104.7 103.0 101.4 99-6 98.0 8760 8160 7580 .7050 6540 6080 5640 5250 4880 4550 4250 110.2 108.4 106.6 1050 103.0 101.5 100.2 99.0 97.5 96.0 94.5 1 2 3 4 5 Btuh Cfm Btuh Cfm Btuh Cfm Btuh . Cfm Btuh Cfm 8620 7800 7100 6470 5830 5350 4850 4370 3960 3600 3260 2950 95.8 91.7 88.7 86.0 83.8 81.6 79.7 77.7 76.0 74.2 72.5 71.2 8700 7900 7180 6530 5950 5400 4920 4430 4050 3680 3350 3040 2750 90.8 87.9 85.2 82.7 80.7 78.9 77.1 75.4 73.6 72.0 70.5 69.2 67.9 8800 8000 7300 6650 6070 5530 5050 4600 4180 3800 3440 3120 2830 2550 86.6 84.0` 81.5 79.3 77.5 75.8 74.3 72.8 71.3 70.0 68.7 67.5 66.3 65.2 8250 7520 6850 6230 5680 5180 4720 4300 3900 3550 3220 2900 2630 2360 81.0 78.8 77.0 75.3 73.7 72.2 70.8 69.5' 68.2 67.2 66.0 65.0 63.6 62.5 7720 7050 6420 5840 5330 4850 4430 4030 3650 3320 3020 2730 2460 2200 76.4 74.5 73.0 71.6 70.3 69.0 67-. 8 66.6 65.5 64.4 63.2 62.0 61.2 60.2 2650 2360 69.8 68.5 2480 2220 66.7 65.6 2300 2060 64.1 63.0 2120 1880 61.5 60.5 1950 1730 59.2 58.1 ^ . . :i 5 Btuh am 8850 8250 7670 7140 6640 6170 5740 5340 4960 4620 4290 3990 106.8 105.0 103-5 102.0 100.5 99.0 97.5 96.0 94.6 93.4 92.0 91.0 . '6- Btuh 7280 6630 6070 5530 5050 4600 4180 3800 3470 3150 2850 2550 2280 2050 1820 1600 Cfm 72.5 71.2 69.8 68.5 67.3 66.0 64.7 63.5 62.4 61.4 60.5 59.5 58.1 57.8 57.0 56.3 j ! 6 Btuh ! Cfm 9050 8420 7840 7280 6750 6300 5850 5440 5060 4700 4370 4060 3760 104.0 102.5 100.7 99.2 97.8 96.5 95.2 94.0 92.6 91.4 90.0 88.7 87.5 ' addTithioenEaql Uuivfat leeqnutiLvaelnegntthlaVnaglSueksrtuf hseadnai nndRindciflufidaewdiirnocaatlocaumlating tlhr.ins-1ta*b1>leviamre: Diffuser and Boo* -- S3 ft; Plenum Takeoff -- 15 ft; Each Elbow -- 12 ft. For <--<-b All cfm values in hasad on standard air. j 1 For Eamvatait Length Value* used and mdufted in this table are: Diffuser and Boot - 40 ft; Plenum Take-off - JO fl; Each Elbow -= 14 ft. For each j additional 14 ft tqmnlat kagtb of boot and difioaer, count one additional elbow. : Allcfm value* are baaed on standard air. .' . ' Section B. For 6-Inch Individual Round Pipe and for Side-woD and Floor Diffusers Bonnet Pressure 0.15 in. Static ... Bonnet Temperature 170 P .! j. i . ` No. of Shows Actual length of Pipe ham Bonnet to Diffiuer--feei ; 1 ' Bmnet Pram,, 0.15 in. Static Section B, For Baseboard Diffusers Only ' Banna Tanpcraturc 170 F . Actual length of Pipe from Bonnet fo Diffuse*--FeeI . Btuh Cfm 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 8700 8060 7460 6920 6430 5960 5550 127.7 124.8 122.3 119.7 117.4 115.0 113.0 j (j j No. of Shows CnpncOr 1 5 10 15 20 25 30 35 40 ; 45- 50 : 55 60 65 70 75 80 ' 1 Btub Cfm 8620 8000 7430 7900 6400 5930 5500 5100 122.8 120.0 117.6 115.3 113 0 111.0 109.0 107.3 0 Btuh am 1 Btuh am 2 Btuh Cfm 3 Btuh am 8570 8000 7450 6910 6420 15960 5560 5150 4800 4450 4160 109.0 107.2 105.5 103.7 102.0 100.4 98.8 97.5 96.1 94.8 93.5 8700 8100 7550 7000 6520 6060 5630 5250 4860 4530 4220 3930 105.5 104.0 102.3 100.7 99.2 97.6 96.2 95.0 93.6 92.3 91.1 90.0 8890 8270 7700 7100 6660 6200 5750 5350 4980 4620 4300 4000 3700 102.8 101.3 99.8 98.2 96.7 95.3 94.0 92.7 91.5 90.2 89.0 87.8 86.5 sko 7870 7320 6820 6350 5880 5460 : 5070 4700 4350 4020 3710 3440 98.4 96.8 95.3 93.9 92.5 91.3 90.0 89.0 88.0 86.9 85.8 84.7 83.5 2 Btuh Cfm 3 Btuh Cfm 4 Btuh Cfm 5 Btuh Cfm 6 Btuh Cfm 8600 7960 7390 6860 6380 5940 5530 5150 4800 118.5 116.2 114.0 112.0 110.0 107.8 106.0 204.5 103.0 8640 8020 7450 6950 6460 6020 5600 5200 4850 4500 114.0 112.0 110.0 108.2 106.5 104.7 103.0- 101.4 99.6 98.0 8760 8160 7580 7050 6540 6080 5640 5250 4680 4550 4250 110.2 108.4 106.6 105.0 103.0 101.5 100.2 99.0 97.5 96.0 94.5 -- 8850 8250 7670 7140 6640 6170 5740 5340 4960 4620 4290 3990 106.8 105.0 103.5 102.0 100.5 99.0 97.5 96.0 94.6 93.4 92.0 91.0 9050 8420 7840 7280 6750 6300 5850 5440 5060 4700 4370 4060 3760 104.0 102.5 100.7 99.2 97.8 96.5 95.2 94.0 92.6 91.4 90.0 88.7 87.5 ' ^ : . 4 Btuh am 8690 8080 7500 6980 6500 6030 5580 5180 : 4800 4450 4120 3820 3520 3250 95.8 94.4 93.0 91.6 90.3 89.0 87.8 86.7 85.7 84.6 83.7 82.6 81.6 80.5 5 Btuh am 8940 8320 7740 7200 6680 6190 5720 5320 4920 4550 4220 3890 3600 3350 3100 93.4 92.2 91.0 89.8 88.5 87.3 86.2 84.8 83.8 82.8 81.7 80.8 79.9 79.0 78.0 6 Btuh Cfm 8580 7960 7380 6850 6350 5880 5440 5040 4660 .4320 4000 3670 3400 3150 2930 90.0 89.8 87.6 86.5 85.5 .84.2 83.1 820 80.9 : 80.0 79.0 78.0 77.3 76.5 76.0 The Equivalent Length Values need and included in this table are: Diffuser and Boot -- 100 ft; Plenum Taks-off --.JO ft; Each Elbow -- 14 ft. For each myMitiaa.r 14 {4 equivalent length of boot and diffuser count one additional elbow. All efm values are based on standard air. ' The Equivalent Length Values used and included in calculating this table are: Diffuser and Boot -- 40 ft; Plenum Takeoff -- 20 ft; Each Elbow -- 14 ft. For each additional 11 ft equivalent length of boot and diffuser oount one additional elbow. > All cfm value* are based on standard air. . f method explained in Chapter 12. Consider the basement or craw! space as a part of the structure and calculate its heat loss. Information m Manual 3* supplements that contained in Chapter 12, particularly with respect to crawl-space heat losses. 2. Determine the required furnace-bonnet capacity from the heat loss of the building. 3. Locate the diffusers on the plan. Allow at least one diffuser for each exposed wall in each room or area of building, and locate them preferably beneath window areas. For residentia! installations limit each diffuser to a maximum of 7,000 Btuh. 4. Determine the required Btuh deliyery of each diffuser. Where more fhn one diffuser is used per room, proportion the heat lorn equally among all diffusers. 5. Measure length and count number of elbows in each duct. From Table 5, determine the duct sixe (5 or 6-in. diameter) - j ;j 1 j 1 ! -1 4 ^. - ' 244 CHAPTER 18 1959 Guide Table 5.... Btuh Capacities and Cfm of Individual Ducts in Perimeter Systems Used in Crasv!-Sace cr 5--Canstructicn {Ccndudsdi Section C For 6-Inch Individual Round Pipe and for Baseboard Diffusers Only Bonnet Pressure 0.15 in. Static _________________________________________ __ ________________ Bonnet Temperature 170 F No. of Bbow* Actool length of Pipe from Bonnet to Diffuser--Feet 5 to 15 20 25 30 35 40 45 50 55 60 65 70 75 80 o- Btuh Cfm 1 Btuh Cfm 2 Btuh Cfm 3 Btuh Cfm 4 Btuh Cfm 5 Btuh Cfm 6 Btuh Cfm 8570 8000 7450 6910 6420 5960 5560 5150 4800 4450 4160 109.0 107.2 105.5 103.7 102.0 100.4 98.8 97.5 96.1 94.8 93.5 8700 8100 7550 7000 6520 6060 5630 5250 4860 4530 4220 3930 105.5 104.0 102.3 100.7 99.2 97.6 96.2 95.0 93.6 92.3 91.1 90.0 8890 8270 7700 7160 6660 6200 5750 5350 4980 4620 4300 4000 3700 102.8 101.3 99.8 98.2 96.7 95.3 94.0 92.7 91.5 90.2 89.0 87.8 86.5 8440 7870 7320 6820 6350 5880 5460 5070 4700 4350 4020 3710 3440 98.4 96.8 95.3 93.9 92.5 91.3 90.0 89.0 88.0 86.9 85.8 84.7 83.5 8690 8080 7500 6980 6500 6030 5580 5180 4800 4450 4120 3820 3520 3250 95.8 94.4 93.0 91.6 90.3 89.0 87.8 86.7 85.7 84.6 83.7 82.6 81-6 80.5 8940 8320 7740 7200 6680 6190 5720 5320 4920 4550 4220 3890 3600 3350 3100 93.4 92.2 91.0 89.8 88.5 87.3 86.2 84.8 83.8 82.8 81.7 80.8 79.9 79.0 78.0 8580 7960 7380 6850 6350 5880 5440 5040 4660 4320 4000 3670 3400 3150 2930 90.0 89.8 87.6 86.5 85.5 .84.2 83.1 82.0 80.9 80.0 79.0 78.0 77.3 76.5 76.0 The Equivslait length Velars used end included in celeuUtinc this teblemie: Diffuser end Boot m 100 ft; Plenum Tske-off uditiosu 14 ft eqiiinleat laith of boot end diffuser count one additional elbow. . Alt dm values are based on standard air. ft; Bach Elbow - 14 ft. For each needed. Sectioo A la for 5-in. duct, Section B is for 6-in. duct using side-wall or floor diffusers, and Section C is for 6-in. duct using baseboard diffusers. Perimeter Extended-Plenum Systems in CrawlSpace or Basement Construction The considerations involved in the design of extendedplenum systems are essentially the same as those of the in dividual pipe system. A simplified design procedure is sum marized as follows: 1. Calculate the heat loss of each room or area lining the method explained in Chapter 12. Consider the basement or crawl space as a part of the structure and calculate its heat loss. Information m Manual 3* supplements that contained in Chapter 12, particularly with respect to crawl-space heat losses. 2. Determine the required furnace-bonnet capacity from the heat loss of the building. - 3. Locate the diffusers on the plan. Allow at least one dif fuser for each exposed wall in each room or area of building, and preferably beneath window areas. For residential installa tions limit each diffuser to a maximum of 7,000 Btuh. 4. Determine the required Btuh delivery of each diffuser. Where more than one diffuser is used per room, proportion the heat loss equally among all diffusers. 5. Measure the length of each duct and count number of elbows from the extended plenum to the diffuser. Note whether top or side plenum take-offs are to be used. From Table 6, determine the duct size needed. (Note: Use that section of Table 6, Sections A to F, which applies both to the type of plenum take-off and diffuser to be used.) ' 6. The cfm values in Table 6 are used with Table 7 for sizing the extended-plenum system. No one extended plenum should exceed 35 ft in length. Design of Return Duct System for Perimeter In stallations With perimeter systems designed in accordance with the foregoing simplified procedures, there is a circulating head of only 0.05 in. water available on the return side of the system. It is therefore necessary that the return ducts be adequately sized and be as short and straight as practicable. The return grilles may be centrally Located, and the ducts may be located in the attic or other unheated .spaces pro vided they are adequately insulated. Return air may be taken from basements and crawl spaces, but should not be taken from confined spaces in which the furnace is located. The following simplified procedure* may be used: 1. Lay out the return-air duct system. Measure the length and count the number of 90 deg turns in each return duct. 2. Total the heat lose of the area served by each return duet. 3. Determine the required duct free area from the length of duct, the number of 90 deg turns, and the heat loss g Table 8. Also determine the free area of the return grille from Tables. Other Perimeter Systems Each of the foregoing procedures can be used with ap proved furnaces that are capable of delivering their rated cfm air volume against a total pressure of 0.20 in. water external to the furnace. This available pressure is usually dis tributed on the basis of three-fourths (0.15 in. water) on the supply side and one-fourth (0.05 in. water) on "the return side. Other systems, such as perimeter crawl-space plenum systems, may be designed by procedures outlined in Manual 4. In addition, procedures for designing 4-in. diameter duct systems are contained* in Manual 10 of the National Warm Air Heating and Air Conditioning Association, Other systems of a proprietary nature but utilizing the perimeter concept of diffuser placement are in common use. These systems should be designed and installed in strict accordance with the manufacturer's recommendations. Such systems usually utilize smaller ducts (4 in. or less) and higher pressures (above 050 in. water). They also may re- Warm Air Heating Systems 245 Table 6.... Heating Capacities and Cfm of Branch Ducts in ExtendedPlenum Perimeter Systems ` Section A. Side Takeoff to 5-Inch Bound Pipe for S*de-woD, Hoar, and Baseboard Diffuser* Extended-Plenum Pressure 0.12 in. Static at 160 F Furnace-Plenum Pressure 0.15 in. Static at 170 F Actual lac^fb from Extended-Wean* to Diffuse*--Feet 5 to 15 20 25 30 35 40 45 so 55 60 0 1 2 3 '4 5 6 Btuh Cfm Btuh am Btuh am Btuh Cfm Btuh am Btuh am Btuh am 8960 97.2 8070 88.4 7340 81.1 6810 75.0 6350 70.4 5970 65.2 5660 63.0 8100 93.1 7290 85.2 6650 78.6 6180 73.0 5750 68.8 5400 64.8 5120 61.5 7310 89.4 6580 82.2 6020 76.0 5600 71.0 5210 67.0 4900 63.2 4630 60.2 6550 86.0 5950 79.3 5460 73.9 5070 69.2 4740 65.4 4440 62.0 4190 59.1 5900 83.0 5400 76.9 4950 71.9 4610 67.3 4300 64.0 4040 60.7 3800 58.0 5310 81.2 .4880 74.6 4500 70.0 4200 65.8 3900 62.5 3670 59.4 3430 56.9 4800 77.7 4400 72.5 4070 68.2 3800 64.4 3530 61.1 3330 58.3 3100 55.9 4330 75.5 3980' 70.7 3680 66.6 3420 63.1 3180 60.0 2990 57.4 2800 55.1 3900 73.1 3550 68.9 3300 64.1 3080 61.7 2870 58.8 2770 56.2 2520 54.0 3510 71.1 3200 67.1 2980 63.7 2770 60.2 2570 57.7 2410 55.3 2270 53.0 3170 69.3 2900 65.7 2680 62.3 2480 59.0 2300 56.7 2160 54.4 2040 62.2 2850 67.8 2620 64.2 2410 61.0 2230 58.2 2070 55.9 1930 53.7 1800 51.8 Note: Wbexu any of the first three runt from the extended-plenum eieeede 30 ft end 3 elbow*, coast 3 extra elbow* for that run. The Equivalent Length Values used and included in calculating thia table are: Diffuser and Boot -- 39 ft; Each Elbow * 13 ft; Side Take-off -- 20 ft. Tapered Extended-Plesom Starting Collar. - Section B. Top Take-off to 5-tndi Round Pipe for Side-wotl, Floor, and Bareboard Diffuser* Extended-Plenum Pressure 0.12 in. iSiafte at 160 F Furnace-Plenum Pressure 0.15 in. Static at 170F No. of Bbow* Actual length from Extended-Hernia to DiSatei--Feet . 5 to 15 20 25 30 35 40 45 50 55 60 0 Btuh '7070 6400 5800 5260 4800 4350 3940 3550 3190 2870 2580 2310 am 77.8 75.6 73.4 71.4 69.5 68.0 66.4 64.8 63.4 62.0 60.6 59.5 1 Btuh 6570 5970 5400 4890 4430 4010 3640 3290 2950 2650 2380 2140 Cfm 72.6 70.8 68.9 67.2 65.6 64.2 62.8 61.5 60.3 59.0 58.0 57.0 2 Btuh 6180 5610 5080 4590 4160 3770 3410 3080 2770 2480 2210 2000 am 68.4 66.8 65.2 63.7 62.3 61.1 60.0 68.7 57.6 56.4 55.3 54.4 3 Btuh 5800 - 5250 4750 4310 3900 3540 3200 2890 2600 2340 2100 1870 Cfm 64.4 63.1 61.8 60.5 59.3 58.3 57.1 56.3 55.5 54.7 53.9 53.2 4 Btuh 5490 4960 4500 4080 3700 3340 3020 2720 2440 2200 - 1970 1750 Cfm 61.2 60.0 58.8 57.8 56.7 55.8 54.9 54.1 53.3 52.6 51.9 51.1 5 Btuh 5200 4710 4280 3870 3510 3180 2880 2580 2310 2060 1830 1640 am - 58.5 57.5 56.5 55.5 54.5 53.7 52.9 52.1 51.4 50-7 50.0 49.5 6 Btuh 5000 4520 5100 3700 3350 3010 2700 2440 2160 1910 1700 1551 Cfm 56.0 55.0 54.0 53.4 52.4 51.7 51.0 50.5 59.7- 49.1 48.6 48.1 Note: Where may of the first three runs from the extended-plenum exceed* 20 ft and 3 elbows, count 3 extr* elbows for that run. The Equivalent Length Values used and included in calculating this tabic are: Diffuser and Boot -- 3$ ft; Eaeh Elbow - 12 ft; Top Take-off -- 60 ft. Tapered Extended-Plenum Starting Collar. - quire special streamlined, low resistance fittings and special diffusers. Some systems also employ higher bonnet tempera tures. When either higher bonnet pressures or temperatures, or both, are to be used, care must be taken to ascertain that the furnace employed is capable of meeting the required conditions. INSIDE WALL DELIVERY SYSTEMS The concept of warm-air perimeter heating is relatively new. The older methods of introducing warm air into spaces use other outlet locations. One of the most common of these has been the use of register locations on a warm or inside 246 CHAPTER 18 1959 Guide Table 6.. .. Heating Capacities and Cfm of Branch Duds in Extended-Plenum Perimeter Systems (Continued) Section C Side Take-Off to 6-Inch Sound Pipe for Baseboard Diffuser* Only Extended-Plenum Pressure 0.16 in. Static at 160 P Furnace-Plenum Pressure 0.16 in. Static at 170 F Actual length from Extended-Plenum to Diffuier Feel 5 10 15 20 25 30 35 40 . 45 50 55 60 :o l 2 3 4 5 6 Btuh Cfm Btuh Cfm Btuh Cfm Btuh Cfm Btuh Cfm . Btuh Cfm Btuh Cfm 9800 106.6 9230 100.4 8740 96.5 8300 91.0 7930 86.8 7600 83.6 7300 80.4 9100 104.4 8550 98.7 8100 93.8 7690 89.5 7350 85.5 7020 82.5 6760 79.5 8430 102.3 7930 97.0 7500 92.2 7130 88.0 6800 84.2 6500 81.3 6260 78.4 7820 100.3 7360 95.3 6960 90.6 6600 86.7 6290 83.3 6020 80.2 5780 77.5 7230 98.5 6800 93.7. 6420 89.4 6110 85.5 5830 82.0 5580 79.1 5350 76.3 6700 96.8. 6300 92.0 5960 88.0 5680 84.2 5400 81.0 5160 78.1 4950 75.3 6200 95.0 5830 90.4 5510 86.5 5240 83.0 5000 80.0 4770 77.1 4560 74.4 5730 93.1 5400 88.9 5110 85.2 4850 82.0 4620 79.1 4410 76.4 4200 73.5 5320 91.7 5000 87.6 4730 84.0 4500 80.9 4270 78.0 4080 75.3 3900 72.8 4920 90.0 4620 86.2 4390 82.8 4170 79.8 3940 77.0 3770 74.4 3580 72.0 4550 88.5 4280 84.9 4050 81.6 3840 78.8 3630 76.1` 3470 73.5 3300 71.2 4210 87.2 3960 83.8 3750 80.6 3560 77.9 3370 75.3 3190 72.8 3040 70.6 Note: Wtere eey of the first three rone from the extended-plenum exceeds 30 ft end 9 elbow*, count 3 extre elbow* for that run. tim Equivalent Length Values used end included in ~this table ere: Diffuser end Boot -- 100 ft; Eech Elbow -- 11 ft; Side Take-off = 10 ft. Tapered Extended-Reaum Starting Collar. - ' Section D. Top Take-Off to 6-btdi Round Pipe for Baseboard Diffusers Only Extended-Plenum Pressure 0.16 in. Static at 160 F Furnace-Plenum Pressure 0.16 in. Static at 170 F - : Actual length from Extended-Plenum to Piffvrer Feet 5 : 10 15 - 20 25 30 35 ' 40 45 . 50 55 60 0 1 2 3 4 5 '6 Btuh Cfm Btuh Cfm Btuh Cfm Btuh Cfm Btuh Cfm Btuh Cfm - Btuh Cfm 8700 95.0 8260 90.2 7880 86.3 7560 83.0 7260 80.0 7000 77.3 6770 74.6 8050 93.2 7640 88.8 7290 85.0 7000 82.0 6700 79.1 6470 76.3 6230 73.8 7450 91.7 6900 90.0 7090 87.5 6560 86.2 6750 6250 84.0 82.9 6470 81.0 5980 79.8 6200 78.1 5740 77.2 5970 5490 75.4 74.5 5740 73.0 5290 72.2 6400 88.6 6080 85.0 5800 81.7 5540 79.0 5290 76.2 5070 73.8 4890 71.3 5910 8T.3 5630 83.7 5380 80.5 5130 78.0 4900 75.2 4700 72.8 4500 70.5 5470 86.0 5200 82.6 4980 79.6 4740 76.9 4510 74.3 4320 71.9 4140 69.8 5160 84.7 4820 81.7 4590 78.7 4380 76.0 4160 73.5 3990 71.2 3820 69.0 4670 83.5 4470 80.4 4260 77.6 4060 75.1 3850 72.7 3600 70.2 3520 68-3 4300 82.4 4140 79.4 3940 76.7 3730 74.2 3560 71.9 3400 69.3 3240 67.5 4000 81.3 3720 80.2 3830 78.4 3530 77.5 3620 75.8 3340 74.9 3430 73.3 3170 72.5 3290 71.0 3020 70.2 3120 68.7 2870 68.1 2980 - 2760 66.9 66.1 Nate: Where any of the first three rues from tlw extended-plenum exceed* 20 ft end 2 elbow*, count 3 extra elbows for the! run. The Equivalent Length Tmluee used |m| included in calculating this table era: Diffuser and Boot 100 ft; Each Elbow 14 ft; Top Take-off Hit Tapered Extended-Plenum Starting Collar. wall. For such systems, the combinations of parts selected as standard by the National Warm Air Heating and Air Con ditioning Association are shown in Tables 9 and 10. A simplified method for selecting the combinations of branches, boots, stacks, and registers, is given in Manual 7 of the National Warm Air Heating and Air Conditioning Association.' In this method, the sizes of the branch ducts are obtained from two tables giving their Btu capacities. The proper combination of parts for each branch can be deter mined if the following information is available. 1. Location of room, that is, whether on first or second story. 2. Actual horizontal length of duct from bonnet to boot, in feet. 3. Btu loss from room to be heated. i 1 Warm Air Hearing Systems 247 Table 6... - Heating Capacities and Cfm of Branch Ducts in Extended-Plenum ' Perimeter Systems (Concluded) Section E. Side Take-Off to 6-Inch Rowed Pipe for Side-wall and Boor Diffuser* Extended-Plenum Pressure 0.16 in. Static at 160 P Furnace-Plenum Pressure 0.16 in. Static at 170 P Actual length from fxlcudod-ttenua to Diffuier--Feet 5 10 15 20 25 30 35 40 45 50 55 60 0 Btuh Cfm 8600 7930 7310 6740 6230 123.2 120.0 116.8 114.0 111.4 1 Btuh Cfm 8560 117.4 7900 114.5 7290 112.1 6720 109.2 6200 107.0 5740 104.8 2 Btuh Cfm 8510 112.7 7890 110.0 7300 107.6 6740 105.3 6230 103.1 5750 101.0 5310 99.0 3 Btuh Cfm 8540 108.2 7900 105.8 7300 103.6 6780 101.5 6270 99.6 5800 97.8 5360 95.9 4960 94.0 .4 Btuh Cfm 8580 7970 104.0 101.9 7370 99.8 6820 97.8 6330 96.0 5850 94.5 5410 92.8 5000 91.1 4620 89.7 6 Btuh Cfm 8720 ' 8080 100.2 98.3 7490 96.7 6940 6440 94.8 _ 93.0 5960 91.4 5490 5080 90.0 . 88.7 4690 87.2 4320 85.0 6 Btuh 8900 8240 7630 7060 6550 6070 5600 5190 : 4800 4430 4100 Cfm 97.0 95.1 93.4 91.9 90.2 88.8 87.3 86.2 85.0 83.8 82.6 Note: Wlwre any of the firxt three mo* from tla extended-plenum exceed* 20 ft end 2 elbow*, count 2 extre elbow* for that run. The Equivalent length ValtM wed and included in --hutig this table are: Diffuser and Boot - 40 ft; Each Elbow = 14 ft; Side Take-off -- 20 ft. Tapered Extended-Plenum Starting Collar. 5800 109.1 5340 102.8 4960 97.4 4610 92.5 '4300 88.3 4020 84.7 3810 81.5 Soction F. Top Take-Off to 6-lnd) Round Pipe far Side-wall and Boor Diffuier* Extended-Plenum Pressure 0.16 in. Static at 160 F Furnace-Plenum Pressure 0.16 in. Static at 170 F - Actual Length heat Extended-Plenum to Diffuser -feet 5 10 15 20 25 30 35 40 45 50 55 60 0 Btuh Cfm 1 Btuh Cfm 2 . ' Btuh Cfm 3 Btuh Cfm 4 Btuh Cfm 5 Btuh Cfm 6 Btuh Cfm 8810 96.0 8390 91.4 7980 87.5 8530 103.2 8660 99.7- "8180 94.4 8020 97.8 7580 92.8 7770 -90.0 7200 88.5 7380 -88.2 6840 85.0 8430 *111.2 7800 108.8 8450 107.2 7840 105.0 7250 102.8 7900 101.1 7320 6800 99.0 97.2 7430 96.0 6900 94.2' 6370 92.4 7010 91.2 6500 89.7 6000 88.0 6650 87.2 6160 85.8 5700 84.5 6340 83.8 6880 82.5 5430 81.4 7210 106.3 6700 100.7 6280 95.4 5900 90.8 5550 86.8 5280 83.2 5020 80.2 6660 104.4 6210 98.9 5790 93.8 5450 89.4 5150 85.7 4890 82.4 4650 79.4 6170 102.2 5730 97.0 5350 92.1 5030 88.0 4750 84.3 4500 81.0 4290 78.3 5700 100.2 5300 95.1 4960 90.6 4650 86.7 4400 83.1 4170 80.0 3970 77.3 5270 98.4 4900 93.4 4590 89.0 4300 85.3 4070 82.0 3840 79.0 3660 76.3 4910 96.7 4560 91.9 4250 87.8 3990 84.2 3780 81.1 3580 78.3 3400 75.6 Note: Where any of tlw first three rhns from the extended-plenum exceed* 20 ft and 3 dhow* ecmnt 3 extre dhow* for that run. The Equivalent Value* used 4 included in caloulating this table are: Diffuser and Boot 40 ft; Each Elbow 14 ft; Top Take-off GOlt Tkpercd Extended-Plenum Storting Cedar. ' - 4. Equivalent lengths in feet of all fittings and of the register. Fig. 7 shows the values of equivalent lengths of fittings com monly used for domestic systems. This simplified method is applicable to structures having heat losses not in excess of approximately 120,000 Btu per hour. The capacities shown in Tables 9 and 10 are bared upon the most reliable data pertaining to friction losses and temperature drops in ducts. They are also based upon a 100 deg temperature rise of the air, and a static pressure available for overcoming friction losses in the external duct system alone of 050 in. of water. The use of this method requires that the fan in the fan-furnace assembly will be capable not only of overcoming the resistance of the external duct system alone, but also the resistances imposed by the blower inlet, the filter, and the furnace casing. Tables 9 and 10 are applicable for the selection of both warm air and return air branches. A depth of 8 in. has been adopted as the standard for trunk ducts, and where a branch 248 CHAPTER 18 1959 Guide Warm Air Heating Systems I" 249 t if I Fig. 7.... Equivalent Length of Fittings and Intakes .. i a 250 CHAPTER 18 1959 Guide Table 7.... Required Size of Extended-Plenum Cfm Handled by Menam Ptoaum Direef>done Indies Cfo Handed by Plenum Plenum Dimen sions Inches Up to 300 301 to 400 401 to 500 501 to 600 601 to 700 8x8 10x8 12 x 8 14 x 8 16x8 701 to 800 801 to 900 901 to 1000 1001 to 1100 1101 to 1200 20x8 22x8 24 x 8 28 x 8 28x8 joins the trunk the required increase shown in the last line of Table 9 or Table 10 refers to an 8-in. trunk duct. Where two branches form a trunk the longer branch is considered to be the trunk and its equivalent width (for 8-in. depth) is increased as required. .. DESIGN PROCEDURE FOR LARGE SYSTEMS' For buildings having a heat loss in excess of 120,000 Btu per hour, the design procedure given in Manual 9 of the National Warm Air Hpat.ing and Air Conditioning Associa tion, may be used. Work sheets 9a, 9b, and 9c are available to simplify calculations.'- The procedure consists of: 1. Calculation of design heat losses from individual spaces in the structure. The calculation of these losses is explained in Chapter 12. 2. Location of registers and return intakes on floor plan, shoeing types of registers, with distance from register to op posite wall and deflection of registers desired. ' 3. 'Laying out a proposed duct system for both warm air and return air sides of the system, and including details of types of fittings and the actual and equivalent lengths of each branch line from bonnet to register, without sixes. (See Fig. 7, Groups 1 through 6, for equivalent length of fittings.) 4. 'Determination of bonnet temperature. If the rating sheet for a furnace-blower unit specifies a fixed value of bonnet temperature, find this temperature in the left-hand column of Table 11. If not specified, use the following procedure: Use Table 11 for buildings having a heat loss be tween 120,000 and 350,000 Btu per hr, or Table 12 for buildings having a heat loss greater than 350,000 Btu per hr. Select short est actual length, including vertical risers and read downward in nearest column in Tables 11 or 12 until lower heavy diagonal line is reached, but do not cross line. Run borixontally to first column of table and note bonnet temperature. Also select long est actual length including vertical risers, and read-downward in nearest column in Tables 11 or 12 until upper heavy diagonal line is just crossed. Run horizontally to left to obtain value for bonnet temperature in first column. Select as the design bonnet temperature any value between these two limits. 5. Determination of air volume to be delivered through each register and the respective register air temperatures. Using Tables 11 or 12 and the design bonnet temperature selected, find the values of cfm per 1000 Btu for each* duct length, and the corresponding register temperature. . 6. Selection of register sizes and pressure losses to produce necessary throw, for the air volumes handled. Use Tables 13 or 14 to obtain required free area and pressure loss of register. Tables 15 and 16 are used in sizing toe duct system. 7. Design of duet system. A. Warm air branches. a. Use Table 16 to select maximum bonnet pressure - usually required for the trunk carrying the maxi mum volume of air (cfm). If the maximum bonnet pressure is not high enough to accommodate the ' ressure loss through the registers, use a higher onnet pressure. If tne register pressure is critically large, it may be necessary to reduce it by either using two registers in place of one, or using smaller deflection angles. . - b. Obtain actual duct loss by subtracting total register fressure loss, as determined from Tables 13 or 14, rom maximum bonnet pressure, c. Obtain the pressure drop in each duct per 100 ft by use of Table 15. ... ' d. Determine duct size by means of air friction chart ' (such as Fig. 2, or Fig. 3, Chapter 21), volume (cfm), and pressure drop per 100 ft of duct. B. Return air branches. (Continued on p. 253.) Actual ft Table 8.... Required Size of Return Air Grille and Duct For Pressure Drop Allowance of 0.05 In. of Wafer Up f 10 Ft n to 20 Ft 21 to 30 FI 31 to 40 Ff Grille Free 16 32 47 63 79 95 111 126 No. of 90 Deg 1 2 3 4 5 . 6 1 2 3 4 5 6 1 2 3 rums. 561 6 Sfoh Duel Free Area 5,000 14 17 20 23 28 28 15 19 22 25 27 28 17 20 23 25 27 29 18 31 24 27 28 30 10,000 27 32 37 42 46 49 29 34 39 43 47 49 31 36 41 45 48 51 33 38 43 47 49 51 15,000 37 44 50 55 60 64 40 46 52 57 61 65 43 49 54 58 63 67 45 51 56 61 64 67 20,000' 46 54 61 66 73 78 49 57 63 69 75 79 53 60 65 71 77 82 55 62 68 74 78 83 25,000 54 64 72 79 86 92 58 68 75 82 88 94 62 71 78 84 91 96 66 74 80 87 92 98 30,000 62 73 82 89 97 104 67 76 85 93 100 106 71 80 88 95 102 108 75 84 91 99 104 110 35,000 69 82 92 101 111 119 74 85* 95 106 114 121 79 91 99 108 117 124 84 94 103 113 119 126 40,000 77 90 100 110 121 130 82 94 105 116 124 132 87 99 109 118 128 137 92 103 113 123 130 140 158 50,000 89 105 119 132 146 158 95 111 124 138 150 161 102 117 129 142 155 166 108 123 135 148 158 170 190 60,000 100 122 139 154 170 181 111 129 145 161 174 184 119 137 151 165 178 189 126 143 158 172 181 193 221 70,000 117 139 158 174 191 203 127 147 164 182 195 206 135 155 171 186 200 213 144 162 178 193 203 216 252 80,000 128 155 175 191 208 222 140 164 182 198 214 225 151 172 188 203 219 231 160 179 195 211 222 235 284 90,000 141 168 188 205 225 244 153 177 195 213 232 248 164 186 201 218 240 256 173 193 209 229 244 262 316 100,000 154 180 200 221 247 285 166 189 209 233 252 270 176 198 217 239 258 277 185 206 227 250 265 285 Note: Where* multiple Dumberof return sir ducts join togeiha, add the individual duet free areas together to determine the free are* of duet Co be oaed from that paint to the return air plenum of furnace. Warm Air Heating Systems 251 fqwr. Length of Fittings end Registers Table 9.... Capacity and Sizing Table--First Story for Worm Air and Refora Air Stock, Broad), end Registers Horizonte! length Fumoce to Register Ducts* Insulated Attic Ducts firsf Story Room Heat loss--fiteh ' Cot. a Up to 70 Eq Ft Col. b Up to 7 8-12 13-17 18-25 28-35 36-45 46-55 . CoLc Up to 5 6-9 1613 24-18 1625 26-35 36-45 46-55 CoL d 7,200 6,700 6,100 5,600 4,800 4,100 3,500 3,000 CoLe 12.500 11,700 10,800 9,900 8.500 7.400 6.400 5.500 CoL f 16,000 15.000 14.000 23.000 11.000 9,900 8.700 7.700 Cot. g 19,100 18,000 - 17,000 16,000 14,200 12,500 11,000 9,600 CoL h 25.000 23,400 21,600 19.800 17.000 14.800 .12,800 11.000 CoL 1 32.000 30.000 28.000 26,000 22,600 19,800 17.400 15.400 Cot. j 80,000 75.000 70.000 65.000 56.500 49.500 43.500 38.500 71 to 100 Eq Ft Up to 7 8-12 13-17 18-25 26-35 36-45 46-55 Up to 5 6-9 1613 14-18 1625 26-35 3645 4655 5.500 5,100 4,800 4.500 3,900 3,400 3,000 2,600 9,900 9.200 8,600 8,100 7,100. 6.200 5,400. , 4,600 13,100 12,300 11,600 10,900 9,700 8.500 7.500 6.500 16,300 15,400 14,500 13,700 12,200 10,800 9,500 8,300 19.800 18.400 17.200 16.200 14.200 12.400 10.800 9.200 28,200 24,600 23,200 21,800 19,400 17.000 15.000 13.000 65.500 61.500 58,000 54.500 48.500 42.500 37.500 33.500 101 to 130 Eq Ft Up to 7 8-12 13-17 18-25 26-35 36-45 46-55 Up to 5 6-9 1613 14-18 1625 2635 36-45 46-55 4,600 4.300 4,100 3,800 3.300 3,000 2,700 2.300 8,500 7.900 7,400 6.900 6,100 5,300 4,700 4,000 11,300 10,600 10,000 9.400 8.400 7.400 6,500 5.400 14,300 13.500 12,700 11,900 10.500 9.300 8.300 7,000 17,000 15.800 14.800 13.800 12,200 10,600 .9,400 8,000 22,600 21,200 20,000 18,800 16,800 14.800 13,000 10.800 56.200 52,600 50.200 47,300 42.000 37.000 32,400 27.000 131 to 165 Eq Ft Up to 7 8-12 13-17 18-25 26-35 36-45 46-55 Up .to 5 6-9 1613 14-18 1625 26-35 3645 4655 4,100 3,800 3.600 3,400 2,900 2.600 27300 2,000 7.300 ` 6,900 6,400 6,000 5.300 4,700 4,200 3,600 9,800 9.100 8,600 8.100 7,200 6,400 5,600 4,700 12.300 11,700 11,000 10.300 9.100 8.100 7,100 6,000 14.600 13.800 12.800 12,000 10.600 . 9,600 8,400 7,200 19,600 18,200 17.200 16.200 14,400 12,800 11,200 9,400 49,200 45.800 41,900 40,300 36,000 31.800 28,100 23,500 166 to 200 Eq Ft Up to 7 8-12 18-17 1825 2635 36-45 46-55 Up to 5 6-6 1613 14-18 1625 2635 36-45 4655 3,800 3,500 3,300 3.100 2.700 2,400 2.100 1.700 6,500 6,100 5,700 5,400 4.800 4,300 3.800 3,000 8,800 8,200 7.700 7,200 6,400 ' 5.700 ' 5,000 3,900 11,000 10,500 9,900 9.300 8.300 7.300 6,400 5,100 13,000 12,200 11,400 10,800 9.600 8,600 7.600 6,000 17,600 16.400 15.400 14.400 12,800 11.400 10,000 7,800 44.100 51.500 38,800 36.000 32.000 28,200 24,700 19.500 Combination Number 41 42 43 44 45 46 47 Stacks6: No. (in parenthesis) and 8ize (1) 10x3Jf (1) 10x3'* (1) 12x3>< (1) 14x3*i (2) 10x3M (2) 12x3& - Rectangular Branch Size Round Branch Size (Diam) 3x8 4x8 5x8 6x8 8x8 10x8 15x8 5 6 7 8 9 10 12 Number of Joist Spaces and Minimum DepthReturn Air 1 at 3 1 at 3 1 at 4 1 at 5 1 at 6 or 1 at 7 or 1 at 9 or 2 at 3 2 at 4 2 at 5 Registers: Low Wall, High Wall, or Baseboard 10x6 10x6 12x6 14x6 (2)10x6 (2)12x6 -- or or (1) 24x6 (1) 30x6 Registers: Floor-Warm Air 8x10 8x10 9x12 9x12 or longer 10x12 12x14 -- Registers: Floor-Return Air 6x10 or 6x10 or 6x12 or 4x14 4x14 6x14 6x14 6x30 6x30 8x30 Trunk Duct Increase, Inches 1 2 3 4 5 7 12 * Uninsulated duets in heated space* and i~rilr-<< ducts in w spaces. Note: For return air a 14xSH tn. stud space may be used instead of luiZK in- stack. Where l2x3M in. or 11x3N in. stack is required. * I4xXH in. stud apace may be used only srhra inside of stud space is smooth and without protruding plaster keys. The number of joist spaces for cnmhtMtfrn fi jj based on txj in. joists. One space may be used with 2x10 in. joists- - The limiting factor for a duet combination is the stack capacity. 252 CHAPTER 18 1959 Guide Egufv. length of fitf/ngi and Registers Co*, a Up to 70 Eq Ft Table 10.... Capacity and Sizing Table--Second Story For Worm Air and Return Air Stack, Brandt, and Kegalert Horizontal length Fvrnoce to Regittor Duets* Insulated Attic Duct> CoL b Up to 7 8-12 13-17 18-25 Col. c Up to 5 6-9 10-13 14-18 26-35 36-45 46-55 19-25 26-35 36-45 46-55 CoL d 6,300 5,700 5,200 4.800 4.100 3,500 3.100 2.800 CoL e 10,900 10,000 9,200 8,500 7,300 6,400 5,600 5,000 Second Story Room Hoot l**----flfuh CcH. f 14.000 13.000 12,100 11,400 10.000 8,800 7.800 6.800 CoL g 17,000 15.900 14.900 13.900 12,400 11,100 9,900 9,000 CoL h 21,800 20,000 18,400 17.000 14,600 12,800 11,200 10.000 CoL I 28,000 26,000 24,200 22,400 20,000 17.600 15.600 13.600 CoL j 70.000 65.000 60,500 57.000 50.000 44.000 39.000 34.000 71 to 100 Eq Ft Up to 7 8-12 13-17 18-25 26-35 36-45 46-55 Up to 5 6-9 10-13 14-18 19-25 26-35 36-45 46-55 5.000 4,600 4.300 4.000 3,400 3.000 4,700 2.300 9,000 8,200 7,600 7,100 6,200 5,400 4,700 4,200 11,900 11,000 10,300 9,600 8,400 7,500 6,700 6,000 14.800 13,900 13,000 12,200 10.800 9,600 8.500 7.500 18,000 16.400 15.200 14.200 12.400 10,800 9.400 8.400 23,900 22,000 20,600 19,200 16,800 15.000 13,400 12.000 59.500 55.000 51.500 48.000 42.000 37.500 33.500 30.000 101 to 130 Eq Ft Up to 7 8-12 13-17 18-25 26-35 36-45 46-55 Up to 5 6-9 10-13 14-18 19-25 26-35 36-45 46-55 4,200 3,900 3,700 3,500 3.000 2,600 2,400 2.000 7.700 7.200 6.700 6.200 5,400 4.700 4,100 3,600 10,400 9,700 9,000 8.400 7.400 6,500 5.800 4.800 13,000 12,100 11,300 10,600 9.400 8,300 7.400 6,500- 15.400 14.400 13.400 12.400 10,800 9,400 8,200 7,200 21,700 19,400 18,000 16,800 14,800 13,000 11,600 9,600 52,200 48,400 45.300 42.300 37.000 32,500 29.000 24.000 131 to 165 Eq Ft Up to 7 8-12 13-17 18-25 26-35 36-45 46-55 Up to 5 6-9 10-13 14-18 19-25 28-35 36-45 46-55 3.800 3,500 3,200 3,000 2,700 2,300 1,900 1.800 6,800 6.300 5.800 5,500 4.800 4,200 3,400 3.300 9,100 8.400 7,900 7.400 6.300 6,700 4,500 4.300 11,400 10,500 9.800 9.200 8,100 7.200 5.800 5,400 13.600 12.600 11,600 11,000 9.600 8,400 6,800 6.600 18,200 16,800 15.800 14.800 12,600 11,400 9,000 8,600 45,500 42,000 39.600 36.800 32.200 28.200 22.800 21.600 166 to 200 Eq Ft . Up to 7 8-12 13-17 18-25 26-35 36-45 46-55 Combination Number Up to 5 6-9 10-13 14-18 19-25 26-35 36-45 46-55 3.500 3,200 2.900 2,700 2.500 2,100 1.900 1.500 41 6,100 5,700 5,300 5,000 4.400 3,900 3.400 2,800 42 8,200 7,600 7.100 6.700 5.700 5.100 4.500 3.500 43 10,300 9,500 8,900 8,300 7,400 6,500 5,800 4,700 44 12,200 11,400 10,600 10,000 8,800 7.800 6.800 5,600 45 16.400 15.200 14.200 13.400 11.400 10.200 9.000 7.000 46 41.000 38,300 35.800 33,400 29.000 25.800 22.800 17,500 47 Stacks6: No. (in paren.) and Size (1) 10x3H (1) 10x3>* (1) 12x3H (1) 14x3X (2) 10x3}* (2) 12x3>4 - Rectangular Branch Size . Roond Branch Size (Di&m) 3x8 4x8 5x8 6x8 8x8 10x8 15x8 5 6 7 8 9 10 12 Number of Joist Spaces and Minimum DepthReturn Air 1 at 3 1 at 3 1 at 4 1 at 5 1 at 6 or 1 at 7 or 1 at 9 or 2 at 3 2 at 4 2 at 5 Registers: Low Wall, High Wall or Baseboard: 10x6 10x6 12x6 14x6 (2)10x6 or (2)12x6 or (1) 24x6 (1) 30x6 - Registers: Floor, Warm Air 8x10 8x10 9x12 9x12 or 10x12 longer 12x14 - Registers: Floor, Return Air 6x10 or 6x10 or 6x12 or 4x14 4x14 6x14 6x14 6x30 6x30 8x30 Trunk Duct Increase, Inches 1 2 3 4 5 7 12 * Unimolited daeto in heeteri spaces and insulated duets m aahwttod spaces. , b Note:For return airs14*3tt in. stud space may be used instead of lOxSH in. stack. When 12s3M in. or 14z3U in. stack is required, a 14x3H in. stud space may be used only when inairtn of stud space is smooth and without protruding plaster keys. The number at joist spaces tor combination 47 is hinod on hi joists. Oas specs may be used with 2x10 joists. ' Tbs limiting (actor (or a dust combination b tha stack capacity. ` Warm Air Heating Systems 253 Table 11.... Selection of Bonnet Temperature, Register Temperature and Register Delivery (CFM)*- b * {Far BaUdingt Moving o Hoot loss between 120,000 and 350,000 BTU/HrJ Register Delivery Volume in CFM per 1000 BTU per Hr. Bonnet t linear Distance from Bonnot to Register, in Feel 10 20 30 40 50 60 70 60 90 100 110 120 130 140 ISO 160 170 180 190 200 210 220 230 240 110 22.1* 108* 107 106 104 103 102 101 100 99 98 97 96 95 94 93 92 91 90 90 89 89 88 88 87 23.lb 23.6 24.2 25.4 26.0 26.6 27.3 28.0 28.8 29.6 30.5 31.5 32.3 33.3 34.6 35.9 37.3 38.6 38.6 39.9 39.9 41.3 41.3 42.7 120 118 116 114 112 111 109 108 106 105 103 102 101 100 99 98 97 96 95 94 93 92 91 90 90 18.4 19.0 19.6 20.3 21.1 21.6 22.5 23.1 24.2 24.8 26.0 26.6 27.3 28.0 28.8 29.6 30.5 31.5 32.3 33.3 34.6 35.9 37.3 38.6 38.6 130 128 126 123 121 119 117 115 113 111 110 108 107 105 104 103 102 101 99 98 97 96 95 94 93 15.9 16.4 16.9 17.6 18.1 18.7 19.3 20.0 20.7 21.6 22.1 23.1 23.6 24.8 25.4 26.0 26.6 27.3 28.8 29.6 30.5 31.5 32.3 33.3 34.6 140 14.0 137 134 131 129 126 124 122 120 118 116 114 112 110 109 107 106 105 103 102 101 100 99 98 97 14.6 15.1 15.7 16.2 16.9 17.3 17.9 18.4 19.0 19.6 20.3 21.1 22.1 22.5 23.6 24.2 24.8 26.0 26.6 27.3 28.0 28.8 29.6 30.5 150 147 143 140 137 134 131 129 127 124 122 120 118 116 114 112 110 109 107 106 105 103 102 101 100 12.6 12.9 13.5 14.0 14.6 15.1 15.7 16.2 16.6 17.3 17.9 18.4 19.0 19.6 20.3 21.1 22.1 22.5 23.6 24.2 24.8 26.0 26.6 27.3 28.0 160 11.4 156 152 149 145 142 139 136 133 130 128 126 123' 121 119 117 115 113 112 110 108 107 106 104 103 11.8 12.3 12.7 13.2 13.7 14.2 14.8 15.3 15.9 16.4 16.9 17.6 18.1 18.7 19.3 20.0 20.7 21.1 22.1 23.1 23.6 24.2 25.4 26.0 170 166 161 157 153 150 146 143 140 137 134 131 128 126 124 122 120 118 116 114 112 no 109 107 106 10.5 10.8 11.3 11.7 12.2 12.6 13:1 13.5 14.0 14.6 15.1 15.7 16.4 16.9 17.3 17.9 18.4 19.0 19.6 20.3 21.1 22.1 22.5 23.6 24.2 180 . 9.7 176 170 166 161 157 153 150 146 143 140 137 135 131 128 128 124 122 120 118 116 115 113 111 no 10.0 10.5 10.8 11.3 11.7 12.2 12.6 13.1 13.5 14.0 14.6 14.9 15.7 16.4 16.9 17.3 17.9 18.4 19.0 19.6 20.0 20.7 21.6 22.1 190 184 179 174 169 165 160 156 153 149 145 142 139 136 133 130 128 128 124 121 119 117 115 113 112 9.1 9.4 9.8 10.1 10.6 10.9 11.4 11.8 12.2 12.7 13.2 13.7 14.2 14.7 15.3 15.9 16.4 16.9 17.3 18.1 18.7 19.3 20.0 20.7 21.1 200 8.6 193 187 182 176 171 167 163 158 154 151 147 144 140 138 135 132 129 127 125 122 120 118 116 114 8.9 9.2 9.6 9.9 10.4 10.7 11.1 11.6 12.1 12.4 12.9 13.4 14.0 14.4 14.9 15.5 16.2 16.6 17.2 17.9 18.4 19.0 19.6 20.3 * Begbter temperature, Fahrenheit. (Use upper value in eaeh croup.) Register delivery volume in cubic feet per minute per 1000 Btu. (Use lower value in Register delivery volumes in column 1 are for sero length of duct. group.) ; j ! | ' 1 - B. Return air branches. ' a. Select a low value of actual duct lose obtained from step b under item A for the suction loss of return duct system. . b. Proceed in siting return air branches by the tmi> method described for the warm air branches. C. Trunk duels for uxirm air and return air aides ofsystem. a. Add air volumes of branches to be handled by each trunk duct. b. The friction loss per 100 ft of trunk duct is deter mined bv taking the smaller of the two values for friction loss for the two ducts meeting at the junc tion. c. Determine.trunk duct size by using an air friction chart, volume (cfm), and pressure drop per 100 ft ' of trunk duct. 8. Selection of Blower. A. Determine total cfm air delivery (the sum of all branch cfm values). B. Determine static pressure requirement. a. For furnace-blower combination units it is the sum of bonnet pressure and suction pressure. b. For blowers separately selected from the furnace it is the sum of bonnet pressure, suction pressure, filter loss, casing loss, losses through air washers, coils, and other devices. 9. Selection of Furnace. A. Determine register delivery (the sum of room Btu losses). B. Determine bonnet capacity. Bonnet capacity -- (total cfm) X (temperature ri3e) X 1.089. C. Determine allowance for pick-up load. For buildings which are heated intermittently, such as churches and auditoriums, it is customary to add from 10 to 25 percent extra furnace capacity tor warming of the structure. ' AUTOMATIC CONTROLS Air stratification, high bonnet temperatures, excessive flue gas temperatures, and heat overrun or lag in a property de signed system, can be largely eliminated through proper care in the planning and installation of the control system." Best results are obtained when the fan is operated as con tinuously as possible, coupled with frequent, short cycles of burner operation. Controls usually employed are : 1. A room thermostat located in the occupied space at a point where there is good air circulation and where the tempera ture is representative of the area being controlled. It is the I. I-- i i ij ! 254 Table 12 CHAPTER 18 1959 Guide Selection of Bonnet Temperature, Register Temperature and Register Delivery (CFM] *.b . (For BviUmg* Moving a Hoot too Greater than 350,000 BTU/HrJ Regliter Delivery VaJorae m CFM per 1000 BTU per Hr. 8onut Temp. linear Distance from Boaoef to Register, a Fee 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 140 138* 136 134 132 130 127 126 125 124 123 121 120 119 118 117 116 115 114 113 112 111 110 109 14.0 14.4 14.8 15.1 15.5 15.9 16.4 16.6 16.9 17.2 17.3 17.6 18.1 18.4 18.7 19.0 19.3 19.6 20.0 20.3 20.7 21.1 21.6 22.1 22.5 150 148 146 143 141 139 137 135 133 131 129 128 127 126 124 123 122 120 119 118 117 116 115 114 113 12.6 12.8 13.1 13.5 13.9 14.2 14.6 14.9 15.3 15.7 16.2 16.4 16.6 16.9 17.3 17.6 17.9 18.4 18.7 19.0 19.3 19.6 20.0 20.3 20.7 160 158 155 152 150 t47 145 143 140 138 136 134 132 130 128 127 126 125 124 123 121 120 119 118 117 11.4 11.6 12.0 12.3 12.6 12.9 13.2 13.5 14.0 14.4 14.8 15.1 15.5 15.9 16.4 16.6 16.9 17.2 17.3 17.6 18.1 18.4 18.7 19.0 19.3 170 167 164 161 158 155 152 150 147 145 143 140 138 136 134 132 130 128 127 128 125 124 123 121 120 10.5 14.4 14.8 15-1 15.5 15.9 16.4 16.6 16.9 17.2 17.3 17.6 18.1 18.4 180 177 143 140 9.7 9.9 10.2 10.5 10.7 II .0 11.3 11.6 12.0 12.3 12.6 12.9 13.2 13.5 14.0 14.4 14.8 15.1 15.5 15.9 16.4 16.6 16.9 17.2 17.3 190 186 182 178 175 172 168 165 162 159 156 153 151 148 146 143 141 139 137 135 133 131 129 128 127 9.1 9.3 9.6 9.8 10.0 10.3 10.7 10.9 11.2 11.5 11.8 12.2 12.4 12.8 13.1 13.5 13.9 14.2 14.6 14.9 15.3 15.7 16.2 16.4 16.6 200 196 191 187 183 179 176 172 169 166 163 160 157 154 151 149 147 144 142 140 138 135 133 131 130 ' 9.2 9.5 9.9 10.3 * Begkter temperature, Fahrenheit. (Um upper value bl each group.) Bcpiter deumr volume in cubic foot per minute per 1000 Btu. (Um lows value ii each group.) * Regiftex delivery volume* in column 1 m for aero length of duet. 13.4 14.4 14.9 15.3 15.7 15.9 the burner. It is frequently of the timed, two-position type. Refer to Chapter 43 for more information on types of room 2. A fan thermostat located in the bonnet of the furnace to start the fan at a bonnet temperature beween 110 and 130 F and stop the fan at about 15 deg below the cut-in point. The lower settings are used for high side-wall register installations and the higher settings for baseboard register installations. For most satisfactory performance these settings should be as low as is feasible without resulting in drafts. 3. A hiah limit control, also in the bonnet of the furnace, to stop the burner independently of the room thermostat if the air temperature exceeds 175 F. The fan thermostat and high limit control are sometimes combined into a ingh unit. 4. A humidistat to regulate the moisture supplied to the rooms on systems which are equipped with humidifying means. This may be of the room type, usually located adjacent to the the main return air duct. 5. Primary and limit controls for the various types of i as vided as required, and are discussed in Chapter 34. ` ADJUSTMENT OF SYSTEM More even room temperatures will result if the controls are adjusted to produce long period fan operation. This is accomplished in automatically-fired forced warm air heat ing systems when the control arrangement is of the type wnere the room thermostat controls the lire, and the blower control (fan switch) controls the blower operation. This procedure as outlined in detail in Manual 6 of the National Warm Air Heating and Air Conditioning Association, is as follows:* 1. Adjust the fuel input in proper relation to the heat loss of tim structure. 3. Adjust the air volume to ] reduce a temperature rise through the furnace of about 90 c eg._ ol about 15 deg. - j. Adjust the fan switch cut-out point as low as practicable. temperature distribution between rooms. 7. Set the room thermostat at the desired room temperature. Close control of room temperature is facilitated by the use of a room thermostat having a narrow operating differential. The heat anticipating thermostat is an example of such a device. ' WARM AIR CEILING PANEL SYSTEMS Warm air ceiling panel heating systems utilize a false ceil ing suspended 314 in. from the ceiling joists which have previ ously been covered on the bottom with sheets of plaster- (Continued on p. toS) ' fi Worm Air Heating Systems 255 Table 13.... Determination of Free Area and Total Pressure Loss of Register for 22 Deg Deflection of Air* u * 4 Register Free Aroo in Square Inches (Upper voice in eodi group) , Pressure loss in Indtes of Wafer (Lower vahe m each group) Cfm Residential Use Keg. Size or Pressure Up to 59 10 x 4 10 x 6 .01 .01 Cfm Residential Use Reg. Size or fnoBie 100-119 12x6 14 x 4 .02 .02 Distance from Register to Opposite Wafl C/d 31-34 35-39 40-49 50-59 50-69 70-79 80-89 A 700-739 243 186 0.02 0.03 127 0.06 85 0.11 60-69 70-99 1UID 12 x 4 10 x 6 12 x 6 . .02 .02 .02 120-129 130-169 170-189 14 x 6 14 x 6 14 x 8 Distance From Register to Opposite Wall 02 740-779 0.02 0-03 0.05 0.10 .02 780-819 230 157 105 0.02 0.05 0.09 .02 254 173 115 0.02 Cfm 190-209 Up to 18 19-21 22 24 25 27 28-30 31-34 35-39 40-49 50-59 860-899 .4 68_1 49 38 29 24 19 0.02 0.03 0.05 0.08 0.11 0.16 900-930 210-229 82 60 45 35 28 23 0.02 0.03 0.04 0.06 0.10 0.13 940-979 230-249 71 54 42 34 28 22 0.02 0.04 0.06 0.08 0.11 0.17 980-1019 250-269 84 63 49 40 32 25 0.02 0.03 0.05 0.07 0.10 0.16 1020-1059 270-299 100 76 60 48 88 30 0.02 0.03 0.04 0.06 0.09 0.13 1060-1099 - ' 340-379 96 73 0.02 0.04 122 95 0.02 0.03 60 0.05 78 0.04 48 0.07 61 0.06 37 0.11 47" 0.09 ... 33 0 .18 1100-1139 1140-1179 380-419 117 94 75 58 39 0.02 0.03 0.05 0.08 C .15 1180-1219 420459 142 113 91 70 47 0.02 0.03 0.04 0.06 0.13 1220-1259 460-499 168 135 108 83 56 0:02 0.03 0.04 0.06 C .11 1260-1299 500-539 159 128 97 66 0.02 0.03 0.05 0.10 1300-1339 540-579 -- 185 147 113 77 0.02 0.03 0.04 0.08 1340-1379 580-619 212 0.02 169 0.03 130 0.04 88 0.08 51 0.18 1380-1419 620-659 192 0.02 147 0.03 100 0.07 59 0-15 1420-1459 660-699 217 0.02 166 0.03 113 0.06 75 0.13 1460-1500 278 190 126 0.02 0.04 0.08 304 207 138 0.02 0.04 332 226 151 108 0.02 0.03 0.07 0.12 ______ 360 245 163 118 0.02 0.03 0.06 0.11 390 265 177 127 0.02 0.03 0.06 0.11 285 190 137 0.03 0.06 0.10 307 204 147 0.05 0.09 330 220 158 0.02 0.05 0.09 _____ 353 235 169 0.02 0.04 0.08 376 251 180 0.02 0.04 0.08 401 267 192 136 0.02 0.04 0.07 0.13 426 0.02 452 0.02 284 0.04 301 0.04 204 0.07 217 0.06 144 0-13 154 0.12 109 0.22 479 0.02 508 0.02 319 0.04 338 0.03 230 0.06 244 0.06 163 0-12 172 0.11 116 0.21 122 0.20 536 356 256 182 129 0.02 0.03 0.06 0.10 0.19 , ^ A8 A' 8' If renter elected based on dotanee from register to opposite wall is unsatisfactory on account of sue or pteuuie laea, it i* permissible to afajitoiie w***P**TM left or right in m table* to obtain a more editable register. If requirements fall in blank apace, mlect two regiatcra m place of one and divide CFM capaeity between the two regiatm b Total presstun (static plua velocity) ltn is baaed os FLAT PACE ADJUSTABLE BAR TYPE and doe* NOT include ataekbead. * Value* on t lie right of He* A and A' abould not be uaed in application# euch aa churches, auditorium*, and concert ball*. d Value* on right of !"* B and B' abould not be uaed in "PP***TM******* auefa aa reaideBtial work, motion picture theater*, court rooms, and schools. - For Boor aiid baseboard regiiters where a velocity of approximately 300 FPM ia rood, the free area -- jqq or approximately, --. Assume> pressure Ion of (MU. j . j 1 ! 256 CHAPTER 18 1959 Guide Table 14.. Determination of Free Area and Total Pressure Loss of Register for No Deflection of Air*-b . Ksgiifc' free Air in Square /ndies {Upper nilue m eocfi group] rretsure ion in indrns of Water Cojoom (Lower Distance from Register to Opposite Wafl Distant* from Register to Opposite Waff 19-21 22-24 25-27 28-30 31-34135-39 40-49 50-59 <50-49 35-39 40-49 50-59 60-69 70-79 80-69 190*-209 \ 15 62 47 37 30 24 18 0.02 0.03 0.04 0.06 0.09 0.15 660-699 / .' I l' 210 143 95 69 49 0.02 0.03 0-07 0.12 0.22 210'-229 76 58 45 36 29 22 0.02 0.02 0.04 0.05 0.08 0.12 700-739 236 160 107 77 54 0.02 0.03 0.06 0.11 0.21 230l-249 69 63 43 34. 26 0.02 0.03 0.04 0.07 0.11 740-779 262 179 119 86 61 0.02 0.03 0.06 0.10 0.18 250*-269 81 63 50 40 31 21 0.02 0-03 0.04 0.06 0.09 0.18 780-819 291 198 132 95 67 0.02 0.03 0.05 0.09 0.17 270*-299 93 73 59 47 36 24 0.02 0.02 0.03 0.05 0.08 0.16 820-859 320 218 145 105 74 0.02 0.03 0.05 0.08 0.15 300*-339. 95 77 61 46 32 0.02 0.03 0.04 0.06 0.12 860-899 352 240 160 115 81 0.02 0.02 0.04 0.08 0-14 340*-379 120 97 77 59 40 0.02 0.02 0.03 0.05 0.10 900-939 385 262 175 126 89 0.01 0.02 0.04 0.07 0.13 3S0M19 119 95 73 50 0.02 0.03 0.04 0.08 940-979 419 2$5 190 137 97 0.01 0.02 0.04 0.07 0.12 420*-459 149 114 88 60 0.02 0.03 0.04 0.07 980-1019 455 309 206 148 105 0.01 0.02 0.04 0.06 0.11 460*-499 171 136 105 71 0-02 0.02 0.03 0.06 1020-1059 493 335 223 161 113 0.01 0.02 0.03 0.06 0.11 500*-639 160 123 84 0.02 0.03 0.05 1060-1099 530 361 241 173 123 0.01 0.02 0-03 0.06 0.10 540*-579 186 143 97 65 47 1100-1139 571 388 258 186 132 93 0.02 0.02 0.05 0.09 0.17 0.01 0.02 0.03 0.05 0.09 0.17 580H519 213 164 111 74 54 1140-1179 0.02 0.02 0.04 0.08 0.15 416 277 199 141 100 0.02 0-03 0.05 0.08 0.16 620*-659 180 127 85 61 1180-1219 0.02 0.04 0.07 0.14 446 297 214 151 107 0.02 0.03 0.04 0.08 0.15 AB Footnotes for Table 14 ' * If register eelectod based oa distance from register to opposite wall is unsatisfactory on aocoont of site or pressure teas, it is permissible to shift one or more spaces left or right in tbe tables to obtain a more suitable register. If requirements fall in blank space, select two registers la place of one and divide CFM capacity between tbe two registers. b Total measure (static plus velocity) loss is based oa FLAT FACE ADJUSTABLE BAR TYPE and does NOT include atackhead. _ ^Values on tbe right of Una A and A' should not be used in epplimtians such as churches. 1220-1259 1260-1299 1300-1339 1340-1379 476 317 228 161 116 0.02 0.03 0.04 0.07 0.14 507 338 243 172 122 0.01 0.02 0.04 0.07 0.13 539 359 258 183 130 0.01 0.02 0.04 0-07 0.12 382 274 195 138 0.02 0-04 0.07 0.12 ^^Valuto on right offline B and B' should not bo used in applications such as resit Mattel 1380-1419 403 290 206 146 0.02 0.03 0.06 0.12 * For floor and baseboard registers where a velocity of approximately 300 FPM is used, the f.ree area CFM X--1--4-4 or approx.im.at.ely, C--FM . A. ssumes pressurel.o..s..s...o..f..0....0..!. 1For any volume under 190 CFM use Table 12. 1420-1459 1460-1500 308 218 155 0.03 0.06 0.10 324 230 163 0.03 0.06 0.10 Warm Air Heating Systems Table 15.... Pressure Drop in Dod 257 fqurvoferrf lengfh of Oucf (ft) 35-44 45-54 55-64 65-74 0.04 0.10 0.08 0.07 0.06 0.05 0.13 0.10 0.08 0.07 0.06 0.15 0.12 0.10 0.09 0.07 0.18 0.14 0.12 0.10 0.08 0.20 0.16 0.13 0.11 Toftrf Pressure Drop in Dod (In. of Water) 0.09 0.23 0.18 0.15 0.13 0.10 0.25 0.20 0.17 0.14 0.11 0.28 0.22 0.18 0.16 0.12 0.30 0.24 0.20 0.17 0.13 0.33 0.26 0.22 0.19 0.14 0.35 0.28 0.23 0.20 0.15 0.38 0.30 0.25 0.21 0.16 0.40 0.32 0.27 0.23 0.17 0.43 0.34 0.28 0.24 0.18 0.45 0.36 0.30 0.26 0.19 0.48 0.38 0.32 0.28 0.20 0.50 0.40 0.33 0.29 75-84 85-94 95-104 105-114 0.05 0.05 0.04 0.04 0.06 0.06 0.05 0.05 0.08 0.07 0.06 0.05 0.09 0.08 0.07 0.06 0.10 0.09 0.08 0.07 0.11 0.10 0.09 0.08 0.13 0.11 0.10 0.09 0.14 0.12 0.11 0.10 0.15 0.13 0.12 0.11 0.16 0.14 0.13 0.12 0.18 0.16 0-14 0.13 0.19 0.17 0.15 0.14 0.20 0.18 0.16 0.15 0.21 0.19 0.17 0.15 0.23 0.20 0.18 0.16 0.24 0.21 0.19 0.17 0.25 0.22 0.20 0.18 115-129 130-149 150-169 170-189 0.03 0.03 0.03 0.02 0.04 0.04 0.03 0.03 0.05 0.04 0.04 0.03 0.06 0.05 0.91 0.04 0.07 0.06 0.05 0.04 0.08 0.07 0.06 0.05 0.08 0.07 0.06 0.06 0.09 0.08 0.07 0.06 0.10 0.09 0.08 0.07 0.11 0.09 0.08 0.07 0.12 0.10 0.09 0.08 0.12 0.11 0.09 0.08 0.13 0.11 0.10 0.09 0.14 0.12 0.11 0.09 0.15 0.13 0.11 0.10 0.16 0.14 0.12 0.11 0.17 0.14 0.13 0.11 190-214 215-239 240-264 265-289 0.02 0.03 0.03 0.04 0.04 0.05 0.05 0.06 0.06 0.07 0.07 0.08 0.08 0.09 0.09 0.10 0.10 0.02 0.02 0.03 0.03 0.04 0.94 0.05 0.05 0.05 0.06 0.06 0.07 0.07 0.08 0.08 0.09 0.09 0.02 0.02 0.02 0.03 0.03 0.94 0.04 0.04 0.05 0.05 0.06 0.06 0.06 0.07 0.07 0.08 0.08 0.01 0.02 0.02 0.03 0.03 0.03 0.04 0.04 0.04 0.05 0.05 0.05 0.06 0.06 0.07 0.07 0.07 290-324 325-374 1 375-424 425-474 0.01 0.02 0.02 0.03 0.03 0.03 0.03 0.04 0.04 0.04 0.05 0.05 0.05 0.06 0.06 0.06 0.07 0.01 0.02 0.02 0.02 0.02 0.03 0.03 0.03 0.03 0.04 0.04 0-04 0.05 0.05 0.05 0.05 0.06 0.01 0.01 0.02 0.02 0.02 0.02 0.03 0.03 0.03 0.03 0.04 0.04 0.04 0.04 o.os' 0.05 0.05 0.01 0.01 0.01 0.02 0.02 0.02. 0.03 0.03 0.03 0.03 0.03 0.03 0.04 0.04 0.04 0.04 0.05 475-524 . 0.01 0.01 0.01 0.02 0.02- 0.02 0.02 0.02 0.02 0.03 0.03 0.03 0.03 0.03 0.04 0.04 0.04 - 525-574 0.01 0.01 0.01 0.01 0.02 0.02 0.02 0.02 0.02 0.02 0.03 0.03 0.03 0.03 0.03. 0.03 0.04 575-625 0.01 0.01 0.01 0.01 0.01 0.02 0.02 0.02 0.02 0.02 0.02 0.03 0.03 0.03 0.03 0.03 0.03 Equivsfenf - Total Pressure Drop in Duct (k of Wafer) length of Dad (ft) 0.21 0.22 0.23 0.24 0.25 0.26 0.27 0.28 0.29 0.30 0.32 0.34 0.36 0.38 (MO 0.45 0.50 35-44 45-54 55-64 65-74 0.53 0.42 0.35 0.30 0.55 0.44 0.37 0.32 0.58 0.46 0.39 0.33 0.60 0.48 0.40 0.34 0.63 0.50 0.42 0.36 0.65 0.52 0.43 0.37 0.68 0.54 0.45 0.39 0.70 0.56 0.47 0.40 0.73 0.58 0.48 0.42 0.75 0.60 0.50 0-43 0.80 0.64 0.53 0.46 0.85 0.68 0.57 0.49 0.90 0.72 0.60 0.52 0.95 0.76 0.64 0.54 1.00 0.80 0.67 0.57 1.13 0.90 0.75 0.64 1.25 1.00 0.83 0.72 75-84 85-94 95-104 105-114 0.26 0.23 0.21 0.19 0.28 0.25 0.22 0.20 0.29 0.26 0.23 0.21 0.30 0.27 0.24 0.22 0.31 0-28 0.25 0.23 0.33 0.29 0.26 0.24 0.34 0.30 0.27 0.25 0.35 0.31 0.28 0.26 0.36 0.32 0.29 0.27 0.38 0.33 0.30 0.28 0.40 0.36 0.32 0.29 0.43 0.38 0.33 0.31 0.45 0.40 0.36 0.33 0.48 0.42 0.38 0.35 0.50 0.45 0.40 0.37 0.56 0.50 0.45 0.41 0.63 0.56 0.50 0.46 115-129 130-149 150-169 ' . 170-189 0.18 0.15 0.13 0.12 0.18 0.16 0.14 0.12 0.19 0.16 0.14 0.13 0.20 0.17 0.15 0.13 0.21 0.18 0.16 0.14 0.22 0.19 0.16 0.15 0.23 0.19 0.17 0.15 0.23 0.20 0.18 0.16 0.24 0.21 0.18 0.16 0.25 0.21 0.19 0.17 0.27 0.23 0.20 0.18 0.28 0.30 0.24 0.26 0.21 0.23 0.19 .0.20 0.32 0.27 0.24 0.21 0.33 0.29 0.25 0.22 0.38 0.32 0.28 0.25 0.47 0.36 0.31 0.28 190-214 215-239 240-264 265-289 0.11 0.09 0.08 0.08 0.11 0.10 0.09 0.08 0.12 0.10 0.09 0.08 0.12 0.11 0.10 0.09 0.13 0.11 0.10 0.09 0.13 0.12 0.10 0.10 0.14 0.12 0.11 0.10 0.14 0.13 0.11 0.10 0.15 0.13 0.12 0.11 0.15 0.13 0.12 0.11 0.16 0.14 0.13 0.12 0.17 0.15 0.14 0.12 0.18 0.16 0.15 0.13 0.19 0.17 0.15 0.14 0.20 0.18 0.16 0.15 0.23 0.20 0.18 0.16 0.25 0.22 0.20 0.18 290-324 325-374 375-424 425-474 0.07 0.06 0.05 0.05 0.07 0.06 0.06 0.05 0.08 0.07 0.06 0.05 0.08 0.07 0.06 0.05 0.08 0.07 0.06 0.06 0.09 0.08 0.07 0.06 0.09 0.08 0.07 0.06 0.09 0.08 0.07 0.06 0.10 0.09 0.08 0.07 0.10 0.09 0.08 0.07 0.11 0.09 0.08 0-07 0.11 0.10 0.09 0.08 0.12 0.10 0.09 0.08 0.13 0.11 0.09 0.09 0.13 0.11 0.10 0.09 0.15 0.13 0.11 0.10 0.17 0.14 0.13 0.11 475-524 0.04 0.04 0.05 0.05 0.05 0.05 0.05 0.06 0.06 0.06 0.06 0.07 0-07 0.08 0.08 0.09 0.10 525-574 0.04 004 0.04 0.04 0.05 0.05 0.05 0.05 0.05 0.06 0.06 0.07 0.07 0.07 0.07 0.08 0.09 575-625 . 0.04 0.04 0.04 0.04 0.04 0.04 0.05 0.05 0.05 0.05 0.05 0.06 0.06 0.06 0.07 0.08 0.08 258 CHAPTER 18 1959 Guide Table 16.... Suggested Bonnet Pressure fodwi of Wafer rpfdCFM Through Any On* Dud Suggested tomet Pressure In. Water Totsd CFM lboeg& Any One Duct SuB8*ifed Boomf Preston hu Water 800-1000 1000-1200 1200-1800 1800-2400 2400 to 3500 0.10 0.10 0.10 0.13 0.14 3500 to 5000 5000 to 7500 7500 to 10,000 10,000 to 12,000 12,000 to 14,000 0.15 0.25 0.375 0.500 0.750 board. Special hangers are used to suspend the false ceiling or heating .panel from the joists. Steel supporting rods are installed through these hangers and metal lath is attached to the rods. The lath is then plastered to a thickness of Va in., making a completely sealed air space above the ceiling. Warm air is delivered to this sealed space through a stand ard warm air duct, installed in the ngal manner. The air is then circulated over the entire ceiling being guided by sheet-metal baffles. After the air has passed over the ceiling, it is returned to the furnace through a return air duct for reheating. The system is closed, and no air is introduced into the heated space from the panel. (See also Chapter 30, Panel Heating.) . Because a warm air ceiling panel system involves a differ ent' type of ceiling construction, its installation is practically limited to new construction. Only automatically-fired and thermostatically-controlled furnace-blower units may be used with this system. The standard automatic heating con trols consisting of a room thermostat, temperature limit con trol, blower control (fan switch), and primary control are all that are required. While warm air ceiling panel heating has particular advantages in one-story utility room houses, it can be just as effectively installed in one- and two-story bouses with basements- . Complete design and installation procedure is given in Manual 7-A of the National Warm Air Heating and Air Conditioning Association.11 SUMMER OPERATION .During hot summer periods a slight cooling effect may sometimes be obtained by the circulation of basement air through the system. This beneficial effect is due to both the increased air movement in the occupied spaces and the small reduction in dry-bulb temperature brought about by flagging gmm air over the cooler basement walls and floor. In areas of high prevailing dew points, however, this prac tice may cause objectionable dampness to develop in the basement. Complete summer air conditioning can be readily com bined with forced warm air systems either by using factorybuilt units incorporating both refrigeration and heating equipment, or in some cases by adapting separate refrigera tion equipment or well-water coils to existing warm air systems. A more complete treatment of residential summer air con ditioning is given in Chapter 46. GRAVITY WARM AIR SYSTEMS In gravity warm air heating systems the motive head pro ducing flow depends upon the difference in weight between the heated air leaving the top of the furnace casing and the cooled air entering the bonnet of the casing. Hence, the mo tive head is very small and the system must allow free flow. A gravity warm air furnace heating plant consists of a fuel-burning furnace or beater, enclosed in a rasing of sheet metal, which is placed in the basement of the building. The heated air, taken from the bonnet on the top of the furnace casing, is distributed to the various rooms of the building through sheet-metal warm air pipes. The warm air pipes in the basement are known as leaders, and the vertical warm air pipes which are installed in the inside partitions of the building are called stacks. The heated air is discharged into the rooms through registers which are set in register boxes placed either in the floor or in the side wall, usually at or near the baseboard. The air supply to the furnace is usually, taken entirely from inside the building through one or more recirculating ducts, although in some an outside air supply duct is provided. Gravity warm air heating systems may be designed9 by following the procedures given in Manual 5 of the National Warm Air Heating and Air Conditioning Association. This publication also contains information terminology, outlet and return locations, and standard sizes of pipe and fittings. The data underlying this information and the design procedure are given in a circular9 issued by the University of Illinois, and are based on research conducted there. REFERENCES . 1 Application Guide for Residential Central Air Conditioning Systems--Winter and Year-Round (National Warm Air Heat ing and Air Conditioning Association, Manual 8, Fifth Edi tion, 1958). * A. P. Krats and S. Konzo: Performance of a forced warmair heating system as affected by volume and temperature of air recirculated (ASHVE Transactions, Vol. 48, 1942, p. 393). * Manual for Adjusting Winter Air Conditioning Systems for Maximum Comfort (National Warm. Air Heating and Air Conditioning Association, Manual 6, 1956). * Warm Air Perimeter Heating (National'Warm Air Heating and Air Conditioning Association, Manual 4, 1956). ' * Pour-Inch Pipe Warm Air Perimeter Heating (National Warm Air Heating and Air Conditioning Association, Manual 10, 1956). . * Code and Manual for the Design and Installation of Warm Air Winter Air Conditioning Systems (National Warm Air Heating and Air Conditioning Association, Manual 7, 1953). *Calculating Heat Losses (National Warm Air Heating and Air Conditioning Association, Manual 3, 1956). *8. Konzo, R. J. Martin, D. S. Levinson, and R. W. Roose: Proposed design procedures for large mechanical warm air heating systems (ASHVE Transactions, Vol. 53, 1947, p. 177). ' Code and Manual for the Design and Installation of Warm Air Winter Atr Conditioning Systems and Year `Round Air Conditioning Systems (National Warm Air Heating and Air Conditioning Association, Manual 9, 1956). ' "S. Konzo and A. F. Hubbard: Automatic controls for forced-air heating systems (ASHVE Transactions, Vol. 40, 1934, p. 37). u Code and Manual for the Design and Installation of Warm Atr Ceiling Panel Systems (National Warm Air Heating and Air Conditioning Association, Manual 7-A, 1950, 3rd ed.). 9 Gravity Code and Manual for the Design and Installation of Gravity Warm Air Heating Systems (National Warm Air Heating and Air Conditioning Association, Manual 5, 1954). 9 A. P. Kratz and S. Konzo: Simplified Procedure for Se lecting Capacities of Duct Systems for Gravity Warm Air Heating Plants (University of Illinois, Engineering Experiment Station Circular 45, December 1942). CHAPTER 19 CENTRAL SYSTEMS FOR AIR CONDITIONING Features of Systems, Zoning, Humidity Control, Cooling load. Heating load. Air Quantity and Temperature Differentia/, Unitary-Central Systems, low- and High-Pressure induction Convectors, High-Velocity Systems, Fan and Coil Units, Evaporative Cooling, Precooling, Sensible Cooling with Unwetted Coils, Selection of System, location of Apparatus THE term, central, applied to an air conditioning system coils provide the necessary sensible coating and dehumidifi implies that the equipment such as fans, coils, filters and cation; The coils may be chilled by direct expansion of an their encasement are designed for assembly in the field ratherapproved refrigerant within the tubes, or by a pump-cir than in a factory as a unit. As a central system usually culated liquid such as water or brine. A water-tight drainage serves several different rooms, or spaces, individual controls tank must be installed under the cooling coil and should are required for each room. 'extend for a distance toward the fan. FEATURES OF CENTRAL SYSTEMS Reheater coils, utilizing steam or hot water, reheat the air in warm weather for control purposes or bring the air One advantage of a central air-supply system is that one apparatus serving many rooms may involve a lower invest ment cost than that for a number of self-contained plants, each serving a single room. A central system may occupy basement or attic space that is relatively unimportant, whereas individual factory-assembled apparatus placed in each room may occupy otherwise valuable space. Another advantage of a central system is accessibility for servicing, to its final temperature in cold weather. For humidification in dry weather, water 6prays are used either separately as shown or combined with the cooling coils having the spray nozzles directed against the coil surfaces. The spray water may be circulated by a small pump from the water tank under the spray chamber. The general requirements for the control of the various components of the central station apparatus are covered since it is possible to provide doors in the encasement for cleaning and inspecting all of the component parts in a manner usually superior to that practicable with compact T nSSSiM itfc" X factory-assembled equipment. In addition service is con centrated in one or just a few places. Central.air-conditioning systems usually are connected by ducts with the various rooms served, and preferably have ! j ! exhaust fans that may effect complete removal and dis posal of any desired proportion of the air. The return-air fan may return air to the supply system for recirculation, as a measure of economy of fuel or refrigeration. i >7?^" t* * If j* ii > j e ; Ti Ti vt Central air-conditioning systems are served by beating and refrigerating equipment which may be located at some distance from the air-supply apparatus, and which may |j !: 1 L Sr t-<5]-- i serve one or more central air-supply systems. Fig. 1 is a sketch of a typical year-round central system. Fig. 1 .... Typical Year-Round Central System I Outdoor air enters from an intake preferably on that ride of the building least exposed to solar heat, and not close to the ground or to a sun-heated or dust-gathering roof. The outdoor-air damper is split into two sections, minimum outdoor-air and maximum outdoor-air, with the maximum outdoor-air damper interlocked with the return-air damper in such a manner that as the outdoor-air volume increases the return-air volume decreases. The return-air duct or connection could come from a return-air fan. All the air passes through filters which must have ample room on both rides of the filters for servicing. The filters may be of a mechanically-cleaned type, a replaceable-cell type, or may be electronic as described in Chapter 24. The cleaned air passes to the equipment that changes its temperature and humidity. Except in very warm climates, heating or tempering coils are required to warm the enter ing outdoor air to a temperature above freezing, the heat being supplied by means of hot water or steam. Cooling in Chapter 43. The functioning of a typical set of controls as illustrated in Fig. 1 is as follows: ` Whenever the fan is started, solenoid air valve or relay E-l, actuated by the fan motor starter, opens minimum outdoor-air damper D-l, places humidist&t H in service, and allows duct thermostats T-3 and T-4 to control the mmrimnm outdoor-air damper D-2 and the return-air damper D-3. When the fans stop, E-l is de-energized to close the out door-air dampers and to close humidifier valve V-4. Thermostat T-l positions steam valve V-3, on the reheater coil, to maintain a constant space temperature. As the space temperature rises, T-l positions reheater valve V-3 to a closed or to a minimum open position, as determined by low limit discharge thermostat T-5. Duct thermostat T-6, in the pre heater discharge, positions preheater coil valve V-l to main tain a constant preheater discharge temperature. On rising outdoor temperature, between 30 F and 65 F, duct thermostat T-3 located in the outdoor-air intake, moves maximum outdoor-air damper D-2 toward the open position 259 260 CHAPTER 19 1959 Guide provided that T-l ia satisfied. At 65 P outdoor, D-2 will be fully open and retum-air damper D-3 will be fully closed. As the outdoor-air temperature rises above 65 F', duct thermostat T-3 positions V-5 in such a way as to bypass low limit thermostat T-5 so that reheater coil valve V-3 is op erated directly from thermostat T-I. As the outdoor-air tem perature rises from 65 F to 75 F, duct thermostat T-4 gradually closes maximum outdoor-air damper D-2 and opens retum-air damper D-3. . Cooling thermostat T-2 positions cooling coil valve V-2 to admit more chilled water as the space temperature rises. Humidistat H positions humidifier valve V-4 to maintain the desired humiaity in the conditioned space. ZONING AND ZONE CONTROL It is apparent that while apparatus like that of fig. 1 would be very desirable for any single room, since in that case the air could be delivered at optimum conditions, the cost of a complete individual system for each room and the space required for the equipment generally would be pro hibitive. Economy is favored if the varying requirements of numerous rooms or zones can be simultaneously satisfied by air from a single central supply system. Various methods are practicable for controlling the tem perature, humidity and air movement in various rooms or zones. A measure of control is attainable merely by propor tioning the flow of air to each room, though usually such control by throttling dampers is difficult to maintain and should be avoided when possible. - Another scheme is to-install a properly proportioned coil in the branch air-supply duct serving each room or zone to warm the air to suit the occupants. For example, the air leaving the fan that serves several zones may be cooled, before entering the fan, to the condition favorable for one zone, and the air for each other zone may be reheated by the branch duct coil to the required temperature. It is also possible to circulate a heat absorbing medium in the branch duct coils to reduce the temperature of the air passing to rooms that would be overheated if they received air at the condition leaving the central air-supply system. When heat transfer devices are placed in branch ducts for improved temperature control, mechanically-circulated water gives excellent results as a heat carrier. The water usually is warmer than the air but it is possible to use water colder than the air. . It is practicable also to use single central air-conditioning equipment similar to that shown in Fig. 1, in conjunction with several fans, one for each room or zone. In such cases there may be a separate reheater on the suction tide of each relatively small supply fan. ' The designer must remember that the various supply fans will compete with each other for air, against the re sistance interposed by the filters, coils, etc., that are used in common under such circumstances, and consequently, unless the fans are of backward-curved blade, non-overload ing type, they may alternate in carrying more than their share of the air, and thereby cause the sir distribution to be chaotic and unsatisfactory. - Another method of controlling temperature in various rooms served by a central air-eupply system is shown in the sectional elevation, fig. 2. The supply fan is placed immediately after the humidifier. When cooling the air in hot weather, the humidifier is not operated. The fan will deliver the air through the heating coil and through the cooling coil to the two air-pressure chambers A and B at the right of these coils. From these chambers many separate ducts, one of whieh is shown, each with a double-blade mix ing damper, may convey the air to the various rooms. The miyinpr dampers, one of which is shown, are interlocked so that as the upper one closes, the lower one opens; selecting between than, air in the required quantity from either the wanner chamber A or the cooler one B. In cold weather no refrigerant is required in the cooling coil, and in hot weather no heating medium is circulated in the heating coil. With this scheme, the control of relative humidity in warm weather is not always sufficiently precise to meet require ments, since the untreated air delivered through the upper coil may be so high in relative humidity that it cannot com pensate sufficiently for the nearly saturated air leaving the lower coil. A reheater could be placed if desired, at the right of the lower coil to bring the air in the lower chamber to the desired relative humidity. The simple arrangement of Fig. 2 is admirable in winter and, except where close control of relative humidity is important, may be acceptable in summer. 1 Another method of attaining temperature control in in dividual rooms with a year-round central air-supply system, is to install a booster fan between the main air-supply duct and the air-delivery opening to each zone or room, as shown in Fig. 3. Air can then be delivered from the central supply fan through the main duct at some desired condition, for instance, 60 F and 45 percent relative humidity. A double mixing damper near the intake opening of the booster fan, controlled by a thermostat in the room or zone that is served by the fan, is interlocked with an outlet exhaust damper in the spent-air opening, so that as more of the room air is recirculated, and as less new air from the main airsupply duct is delivered into the room, the spent-air outlet is throttled in proportion. In many large installations this principle is applied successfully for zoning different stories in multi-story office buildings, the main supply fan being on the roof, and each booster fan being used for supplying the rooms of one orientation of each story. In other cases the booster fans serve only tingle offices, and therefore are small enough to be concealed above ceilings alongside the main supply duct. There may be installations in which the use of recirculated air for mixing with new refrigerated and nearly saturated air to control temperature and relative humidity is objec tionable. In such cases the general recirculation arrange ments of Fig.' 1 may be omitted, and heat transfer coils . located in the ducts may be used. In some cases where general recirculation is not acceptable, as for all the rooms in an entire building, use of the local circulation of Fig. 3 may solve the problem. HUMIDITY CONTROL In winter, room relative humidities in excess of 30 percent are seldom required in a system designed for comfort con ditioning only, and a low saturating efficiency may. be de sirable, or even necessary, especially if the same volume of Rg. 2 .... Alternate Arrangement of Equipment for Controlling Air Conditions in Central-Air Supply System Central Systems for Air Conditioning 261 air is handled as in summer. With a spray-type dehumidifier the main sprays may he shut off And only the eliminators need be flooded; which may give sufficient moisture. In other cases, such as those in which cooling coils are sprayed, the spray-water supply may be throttled. If the saturation efficiency of the sprays is too low, the 6pray water may be heated. The amount of heat put into the spray water by open or closed water heaters will be equal to that required to bring the dew-point temperature of the air entering the sprays up to that required before entering the preheater. It is possible, where clean steam is available, to introduce steam directly into the air stream to produce the desired dew-point temperature of supply air. However, the steam, must be exceptionally clean, or objectionable odors will result. It should be noted that the quantity of outdoor air to be introduced is affected by infiltration and leakage. Infiltra tion will reduce the quantity to be introduced by the system, while leakage may have to be offset by an increase in the quantity of outdoor air. COOLING LOAD The method of determining the cooling load for a condi tioned space or spaces is outlined in Chapter 13. As pointed out therein, many of the items of heat gain are variable and do not reach their maximum values simultaneously. Proper consideration of thasa peaks and the avoidance of pyramid ing these peaks in the cooling load calculations are stressed. Maximum solar heat gain on an east exposure is seldom coincident with the maximum outdoor wet-bulb tempera ture. A discussion of the factors affecting the actual instan taneous cooling load will be found in Chapter 13. HEATING LOAD Methods of calculating the heating load are shown in Chapter 12. Many of the factors outlined in Chapter 13, Cooling Load, such as zoning, non-simultaneous peak&7 and diversity, apply in the reverse manner due to the heating requirements instead of the cooling requirements. However, these factors affect the heating load from the standpoint of control of inside conditions, overall performance, and econ omy of operation more than from a capacity of equipment standpoint. It is not only necessary to heat a building or space to its design conditions when there is but the merest fraction of normal occupancy,.and when there are practically no lights, internal heat, or solar radiation, but it is also necessary to provide capacity to heat the building quickly when tiidden cold follows relatively warm weather, as may occur after a week-end or holiday shut-down. However, in norma! operation rinring week-end? and holidays, buildings are usually kept at a holding temperature to prevent the freezing of services. In many cases, less fuel is required to operate the heating plant at a near-normal rate and main tain the building or space at a temperature of 50 to 65 F at such times, than to shut the system down and then bring the temperature back to normal through forced operation of the heat-generating equipment with a consequent loss in efficiency. AIR QUANTITY AND TEMPERATURE DIFFERENTIAL The difference between the room-air temperature and the supply-air temperature at the outlet to the room is known as the temperature differential. In the theoretical of a dehumidifier having 100 percent saturating efficiency, and where this air is delivered directly to the room without temperature increases'due to heat gain, then the temperature differential is the difference between room temperature and apparatus dew-point temperature. If duct heat gains are considered a part of the room load, this still holds true. The apparatus dew point, as outlined previously, is fixed by - the latent and sensible loads of the space, but in many cases, it is desirable to deliver more air to the spaces 1-hn.n is in dicated by the difference between the room temperature and the apparatus dew point. It has been indicated that where a percentage of air is passed through the dehumidifier without being treated, the relationship is modified in direct proportion, and that if room air is passed through untreated, no effect on the heat balance results. Similarly, if room air is passed around the dehumidifier and mixed with the treated air, the heat balance is not adversely affected. Therefore, if the quantity of air passed through the dehumidifier is determined by the usual methods, room air can be passed around the dehumidifier and mixed with the dehumidified air, increasing the supply- . air quantity and temperature and decreasing the tempera ture differential. .Thus if the difference between the room temperature and the apparatus dew point indicates that 10,000 cfm at 30 deg below room temperature will be re quired to hold conditions, that quantity can be passed through the dehumidifier and cooled to 30 deg below the room temperature, then mixed with 10,000 cfm of room air, resulting in a supply-air quantity of 20,000 cfm and a temperature differential of 15 deg instead of 30 deg. Air- supply outlets and grilles having a high induction ratio are available, and through their induction effect cause a large amount of room air to be mixed with the supply air within a short distance of the grille. A proper selection of outlets may make it possible to introduce air at low temperatures and high velocities without causing objectionable drafts or cold spots, but care must be used to see that too little air motion is not a result. Small temperature differentials may be required for this reason. While the use of a large tempera- . ture differentia! results in a saving in initial cost of fans ^ and ducts, and in the operating cost of fans, thia differential should be carefully considered. If the sensible heat load of a space is subjected to substantial variations, smftU tem perature differentials should be considered, since systems employing small temperature differentials require less pre cision in controls. . Reduction of air quantity by slowing down the fans for the winter season, and increasing the temperature differen tial, often is feasible. A saving in fan power can thus be - effected, provided the air distribution remains adequate. 262 CHAPTER 19 1959 Guide Extremes should be avoided in ail cases. For 'summer air conditioning, low supply-air temperatures result in larger heat gains to the air passing through the ducts, as well as in poor control. Too high a supply-air temperature may re sult in excessive initial and operating costa. Suggested limits for the temperature differential are from 12 to 25 deg, the actual selection being based on the requirements of the par ticular case. For winter air conditioning, too high supply-air temperatures result in excessive heat losses from the ducts and stratification within the room unless thorough mixing is assured, while too low supply-air temperatures may cause drafts, high operating costs, etc. Suggested limits are from 15 to 35 deg. There can be no set rule, and each case should be judged according to its particular requirements of the installation. Reference may be made to Chapter 20 for further dis cussion of the most satisfactory design difference between the entering air temperature and volume in relation to the desired room condition. . UNITARY-CENTRAL SYSTEMS Many different types of central air-conditioning systems with room units of various designs have been developed for multi-room buildings, such as office buildings, hotels, and hospitals. The primary object in using these systems is to save space by reduction of duct rises or by entirely eliminat ing ducts. In new buildings, small ducts may reduce the overall building height; in existing buildings, the use of small ducts is frequently imperative and may even play a decisive role in the acceptance of air conditioning for these buildings. Also, multi-room buildings frequently .require a high degree of toning or individual room control, which the systems must supply. These buildings usually have a large perimeter relative to the floor area. Air-conditioning units are usually installed beneath the windows. Where the spaces to be conditioned extend a considerable distance from the outer wall into the interior of the building, as in some office buildings, a'separate system or zone for the conditioning of the interior portions may be required. In these cases the interior system handles the relatively small and steady loads, due to such items as lights and people; while the exterior system must cope with the relatively large and variable loads imposed by sunshine and temperature difference through walls and glas3. Descrip tions of the four common unitary-central systems follow.' Induction Convectors--Low-Pressure Type Induction convectors located in the room that is to be served, utilize a jet of primary conditioned air to mix with a stream of secondary room air as shown in Fig. 4. The mix ture is discharged into the room through a grille at the top of the convector. Heating coils are located in the secondaryair stream. The output is controlled either by manually or automatically throttling the air jet. Heat may be supplied to the coil in summer as well as in winter. These induction con vectors present several advantages. Since the secondary air stream is thoroughly mired with the high-velocity lowtemperature air stream before leaving the discharge outlet of the device, the resultant temperature of the mixture is satisfactory even though the primary air is introduced at a temperature too low for ordinary methods of distribution. One of these devices usually is provided under each window in place of the customary direct radiator, and combines the air-distribution system with the heating system. An air- conditioning system without induction convectors may re quire installation of' direct radiation for maintenance of minimum temperatures during air-conditioning shut-down periods, but when induction convectors are used they may be selected with heating coils of sufficient capacity to main tain, by thermal circulation, a reasonable temperature when the primary-air supply system is shut off. The use of lowtemperature, dehumidified air that has not been reheated or mixed with room air before delivery to the room, may permit a reduction in fan capacity and the use of smaller ducts. In some cases a bypass may be desirable in order to maintain the primary-air volume and to provide additional control. This system can provide a degree of zoning that is usually difficult with conventional design because the air delivered by each unit can be controlled individually. Se lection of induction convectors should be made with due regard to noise level. The inductive capacity of the device increases with the jet velocity, but high jet velocities may result in objectionable noise. The units are supplied with primary air from one or more central stations with the primary air providing all ventila tion and handling the entire cooling load. The central ap paratus is arranged in general conformity to Fig. 1 except that the central reheater is omitted since each unit has its own rebeater. The controls are arranged to maintain a substantially-constant supply-air temperature equal to that required for maximum cooling, final control is obtained by means of a room thermostat, or remote bulb thermostat in the unit having its measuring element in the recireulatedair stream. The controlling thermostat operates the coilsupply valve and a damper operator on the primary-air damper in sequence. At maximum heating load the valve is wide open and the primary-air quantity is at a minimum. As the space temperature tends to rise, the valve is first gradually dosed, then the primary-air quantity is gradually increased from minimum to maximum Alternately the pri mary-air quantity can be kept constant while final control is achieved by the individual heating coils. If variable air quantities are to be handled by the primary-air fan, some form of fan-capacity control is necessary. Induction Convectors--High-Pressure Type Another type of induction convector, Fig. 5, employs nozzles that produce a high-velocity air jet without objec tionable noise. The term, high pressure, is to some extent inaccurate, since the air pressure at the nozzles, while several times that used with a low-pressure induction convector, is still less than the total resistance pressure of a conventional central system. The high-velocity jet of primary air induces Fig. 4 .... Induction Unit (Low-Pressure Type) Fig. 5.... Induction Unit (High-Pressure Type) Central Systems for Air Conditioning 263 a flow of air from the room through. coils located in the secondary-air stream and supplied with chilled water in sum mer and with hot water in winter. The chilled water re moves a large portion of the sensible heat in summer and the hot water supplies the sensible heat loss in winter. The primary air is delivered at a sufficiently low dew point to compensate for the latent heat gain in summer. In winter the primary air is supplied at a sufficiently high dew point to take care of latent heat losses. Control of temperature is obtained by throttling the water quantity supplied to the secondary coil. The required flow of primary air is greatly reduced due to the fact that a portion of the sensible heat load is carried by the secondary air stream. Since the pri mary quantity is small, very high velocities can be main tained in the supply ducts without requiring fan power in excess of that for a conventional system. Therefore, the sup ply ducts or pipes can be very small and can be run in chases, or furred in at columns along with the water pipes. The primary air is treated in the usual manner to reach the required dew point .and a* surface or spray dehumidifier or a dehydrator may be used. The primary-air quantity is sufficient for ventilation purposes and frequently consists entirely of outdoor air. Fig. 6 shows the general arrangement and control of the system. The operation of the controls is as follows: The final temperatures in the spaces are controlled by in dividual valves, either automatic or manual, which throttle the flow of secondary water to the unit coils. Where automatic valves are used, the ` thermostats are of the heating-cooling type so that a rise in room temperature opens the valve when cold water is circulated and closes the valve when hot water is being supplied. Thermostat T1 controls the pre heater steam valve Vl to maintain a temperature of about 45 F leaving the preheater. Thermostat T2 controls the max imum outdoor-air and return-air dampers so that `the air entering the dehumidifier is maintained at 50 F whenever outdoor air conditions persut. ** . During the heating cycle, thermostat T3 and valve V2'are inoperative so that cool primary air is supplied to the units but at the same time thermostat 76 operates valve V4 so that the secondary water is heated. Thus the combination of cool primary air and hot secondary water can provide heating or cooling as required..The primary pump and water cooler are inoperative. ` When the outdoor air is no longer suitable to provide sufficient cooling through the primary air system (typically about 50 F) the system is changed from heating to cooling operation. The primary pump^is' started and supplies chilled water to the dehumidifier. Thermostat T4 controls mixing valve V3 so as to maintain the secondary water at temper atures in the range of 50 to 55 F. At outdoor temperatures below 80 F thermostat T3 regulates reheater valve V2 so that warm primary air is supplied at the same time that cold secondary water is fed to the units. The changeover from heating to cooling is usually manual and the exact time is not too important because both heating and cooling are avail able in either ease. During the cooling cycle, thermostat T7 acting through thermostat T3 readjusts the primary-air tem perature downward as the outdoor-air temperature increases from the changeover point to about 80 F so that above thin temperature the primary air is at the apparatus dew point. In some buildings the primary-air system and water cir cuits are zoned according to exposure, but because both heating and cooling are available at the units whenever either is needed, such zoning is not always used. All-Air High-Velocity Systems All-air high-velocity systems are air-conditioning systems in which the duct velocities and static pressures are such that special control and acoustic equipment is required for proper introduction of the conditioned air into the space to be served. All-air high-velocity duct systems are of either single-duct or dual-duct types. The single-duct system is usually zone controlled. The 'single supply temperature is established for each zone and therefore variations in individual rooms must be compen sated by throttling the air supply volume. Throttling is limited to the lowest air quantity required for ventilation and for satisfactory air distribution which depends to a large degree on the performance of the type of air outlet used. - Dual-duct systems deliver the entire air supply to cold- . and warm-air supply ducts, from which it is distributed into air-mixing valves or acoustic terminal devices. (A mixing valve is a mechanical device that serves to proportion air from a cold-air duct and a warm-air duct into a common outlet, or duct. An acoustic terminal device is an air dis tribution unit consisting of an air valve, acoustical attenua tion chamber, and an air outlet.) . The proportion of cold air and warm air delivered to the air-mixing valves or acoustic terminal device is thermo-, statically controlled. This control, together with controls for maintaining fixed volumetric delivery, results in a constant volume of air supply at a temperature that satisfies the load. Mixing valves may be used to deliver large quantities of mixed or blended air at high velocity to a single-duct system equipped with acoustic terminal devices supplying the needs of an entire zone or area. The air coming from the miring valve may also be reduced in pressure (either in the miring valve itself or by means of an additional valve or damper) so that it can be distributed by a conventional low-velocity duct system. In this case, noise attenuation is accomplished by a length of lined duct, or by a separate noise attenuator installed after the mixing valve. For greater flexibility, acoustic terminal devices which usually are equipped with one air outlet only, may discharge y into a low-velocity rigid or flexible duct equipped with several air outlets. Refer to Chapter 21 on Air Duct Design for a discussion of the design of high-velocity ducting. The general arrangement of a typical dual-duct system is shown in Fig. 7. In some arrangements, two supply-air fans are used with one fan supplying the cold-air duct and the other the hot-air duct. The warm-air fan handles only re circulated air so that operating economy is slightly improved. The maximum outdoor-air damper and the preheater are controlled as in Fig. 1 so that when the temperature of the 264 CHAPTER 19 1959 Guide / L-aia-wiymc ^ I ROOM UNIT \*m*t coZr! matmc 1 ! 11 hu.oa| | H PROCATtft v'woudr r 1 lMM A SUPPLY Mr n< COLO AIR SUPPLY TO OTHER ROOM UMTS TO OTHER ROOM UMTS OOLLCft PUUP G? ^------- 1 wrcR '"`COOLING con. aA. - OUTDOOR AIR fig. 7.... Schematic Arrangement or Dual-Duct System outdoor air is favorable it is used increasingly instead of return air. The warm-air supply-duct temperature is controlled by a thermostat, T2, Fig. 7, in the air leaving the heating coil. Thermostat T2 is reset by thermostat T1 in accordance with variations in outdoor-air temperature. Whenever, out-' door-air temperature is not low enough to accomplish the required cooling, the cold-air supply-duct temperature is regulated by the cooling coil. The final temperature in the conditioned areas is controlled by the individual air-mixing units. . Air-mixing room units under control of the room thermo stat draw warm and cold air from the ducts in accordance with the room requirements, affording individual room con trol without zoning. Fig. 8 shows schematically one type of room unit designed for dual-duct systems. The warm and cold air pass through the three-way miring damper which delivers air at the temperature required by the room. Some units are placed under windows, while others are mounted in the ceilings from which air may be delivered to the room through ceiling, wall, or window outlets. Some units are a-lsn provided with volume regulators to maintain a steady flow condition. . This system is best suited for multi-room or multi-zone installations, and may be of either high- or low-velocity and high- or low-pressure type with substantially the same con trol methods. It is often applied to high-velocity systems with long distribution mains, and consequently high-static - fan pressures; although extremely high static pressures are seldom justified. With two supply mains, the system static pressures vary as a result of changing demands for heating or cooling. Thus volume regulation often becomes necessary. Extreme variations of flow to different rooms may be some what limited by static-pressure regulators and volume dam pers at selected points along the mains. There are some, in stallations where volume control at each room supply is desirable to maintain close control regardless of static-pres sure changes in the ducts, and incidentally to facilitate bal ancing of the distribution system. Air-capacity requirements are generally governed by sum mer cooling loads, and general practice is to supply the cold air to the cold-air duct at 25 to 30 deg below the established room temperature, this being satisfactory with suitably de signed room outlets. Fan and Coil Units Another type of room convector used in connection with central cooling and heating plants is known as the Fan and Coil Unit-(see Fig. 5, Chapter 16). These units, like induction units, are located around the periphery of a building, usually under windows, and are equipped with fans and a water-type heating-cooling coil. They normally take air for ventilation directly from out doors, and have a manual damper for adjusting the quantity of outdoor air within certain limits. Positive closing of this damper when the fan stops, can be obtained by adding a damper operator actuated by the fan-motor switch. Hot water supplied during the heating season frequently is varied in accordance with outdoor temperature. Cold water for use during the cooling season should be supplied at a fixed tem perature low enough to provide the proper amount of de humidification. These units sometimes are used with a primary-air sys tem that supplies the outdoor ventilation air and handles the latent load. In such cases the primary air unit is con trolled as explained under the section Unitary-Central Sys tems, and may be of either the low- or high-pressure type. The combined heating-cooling coil of each unit may be controlled by a valve in the water supply line to each unit, actuated by a thermostat in the room or recirculated air of the unit. The thermostat is of the heating-cooling type. EVAPORATIVE COOLING In climates where, on the hottest days, the outdoor wetbulb depression is relatively great, it may be possible to replace mechanical refrigeration, or other cooling sources, and use the evaporative cooling effect. A well-designed air washer using recirculating sprays will reduce the entering dry-bulb temperature to within a degree or two of the en tering wet-bulb condition. Thus, it may be possible that, with air entering at 100 F dry-bulb, 60 F wet-bulb, a leaving condition of 62 F dry-bulb, nearly saturated, ran be ob tained. Under some conditions of latent and sensible heat load, this evaporative cooling may be adequate. At times when the outdoor wet-bulb temperature is not low enough to permit the use of straight evaporative cool ing, it is still possible to use precooling convectors with re frigeration, well water, or a cooling tower, as the basic source of sensible heat removal to reduce the wet-bulb tem perature of the air before it enters the spray chamber. Where internal heat loads are high, this scheme may be more economical than one using return air. Where the required supply-air dew point is too low to permit straight evapora tive cooling, and where the sensible heat load is not too great, intentional partial saturation may be employed. In this case the low dew point of the outdoor air is utilized by permitting some of this air to pass through the humidifying sprays untreated, or to bypass the humidifier. All of these fig. 8....Room Air-Mixing Unit for Dual-Duct System Central-Systems for Air Conditioning 265 remarks with regard to evaporative cooling are based on the assumption that all of the supply air will be taken from outdoors. Provision should be made in most cases for the return qf some air from the conditioned spaces for control purposes, as well as for economy of fuel in winter. PRECOOUNG Where sufficiently cold cwater from wells or streams is available, a saving in refrigeration may be obtained by the use, in location ahead of the dehumidifier, of precooling coils through which the cold water is circulated. The resultant cooling of the air decreases the load to be cammed by the and refrigeration plant. In normal practice the water, after passing through the precooling coils, may be further utilized in the refrigeration plant condenser. The economic advantages of this scheme are apparent, and it is frequently used. - SENSIBLE COOLING WITH UNWETTED COILS Under favorable atmospheric conditions where a large wet-bulb depression exists and the dew point of the outdoor air is sufficiently low at all times, acceptable cooling may be obtained by removing only the sensible heat from the out door air delivered to the rooms. Under this condition of a great wet-bulb depression, a temperature-reducing coil may be located in the air stream and supplied with water from a cooling tower. When humidity control is desired, sprays to saturate or partially saturate the air may be used down stream from the unwetted coil. Saturation or partial satura tion after the coil will reduce further the dry-bulb tempera ture and the air quantity required. This system has very definite application in hot dry climates. SaECTlON OF TYPE OF SYSTEM Low buildings with large floor areas may be divided, into sections or zones with separate central air-supply systems to facilitate temperature control. In the case of large de partment stores it may be possible to provide a single con ditioner, with a fan delivering the conditioned air to local mixing fans which supply the various departments or spaces. This application is limited by the practicability of running the large conditioned-air ducts to the various recirculating fans. Each vertical section of the building also may be sup plied by a separate fan delivering conditioned air to local mixing fans. In many cases the most economical and satis factory scheme may be to employ a hot water or steam re heater in each branch duct. Where vertical sectionalizing is not indicated, the building may be divided into horizontal groups, each handled by a central system and adequately zoned. In some large buildings, apparatus rooms for the systems may be located in the basement and attic and on intermediate floors. ' In high buildings the necessity for horizontal sectionaiizing may be suggested by the size of air-supply and return risers, and by the extent to which they encroach upon usable space. Each story should be cut off by doors from other stories, as otherwise the cool air tends to collect in the lower story and the warm air is forced to the' upper story. Balconies and large lobbies in theaters and. similar high rooms frequently justify the use of separate zoning fans, to counteract the tendency of the heavier, cooler air to collect at the lower levels of these spaces. Fans operate at full capacity continuously in many sys tems, and therefore should be selected for good efficiencies. In winter when higher temperature differentials are used, it is sometimes practicable to deliver smaller air quantities than when cooling. In r-limfttftfl where winter temperatures fall below freezing, the tempering coils should be of the steam-distributing type; or if they are heated by a liquid, this liquid should contain some antifreezing substance such as ethylene glycol. If hot water is used in cold climates, the control of air temperature should be obtained by means of face and bypass dampers rather than by throttling the valves, to prevent damage due to freezing. If zone reheaters placed in supply-duct branches are em ployed, they should be of such type as to be heated over the entire surface so that no temperature stratification can occur in the delivered air. Steam-distributing-tube coils or me chanically-circulated water coils are satisfactory in such cases, and throttling valves may be used. Refrigeration equipment must be carefully selected to satisfy the particular requirements of each installation. For some small plants the evaporator may be placed in the air stream, when type of refrigerant and nature of occupancy . permit. In many cases, chilled water coils are required by considerations of safety. Where low temperature and rela tive humidity are necessary, brine, often of calcium chloride, may be indicated. Condensing requirements must have economic analysis. Wells, public water service, cooling towers, and evaporative condensers present possibilities for consideration. Condenser water may have a secondary use for roof sprays in hot weather, and is usually suitable for lawn sprinkling. Most health department rules in cities prohibit any connection from refrigerant condensers that might permit the water to . be used for drinking or lavatory purposes. Practically without exception, air cleaners should be pro vided for both outdoor and recirculated air. Control of temperature and of relative humidity by auto matic means is vital, if comfort and economical operation of air-conditioning equipment arc to be attained. The insulation of ductwork may be necessary to prevent condensation of moisture either inside or outside of ducts, housings, and fan encasements or to prevent a change of temperature in ducts passing through hot or cold spaces. In general, the apparatus should be arranged to have a straight-line air flow. Each change in direction increases air resistance and, in addition, elbows and offsets may cause eddy currents resulting in stratification. The usual order of equipment location, beginning at the outdoor-air intake, is: weather hood or louvers, outdoor-air dampers, return-air connection, filters, tempering coils, cooling coils or sprays, bypass connection with or without prebeaters, reheaters, fan and distributing ducts. Screens at the intake prevent the entry of large foreign matter, birds, etc. A hood or louver at the outdoor-air intake prevents the entry of rain and snow. Since in most climates there are many days during which use of 100 percent out door air unheated or uncooled may be economical, the areas of all air-passing and treating apparatus should be large enough for such a volume, and the exhaust or spent-air equipment should be capable of discharging out of doors all of the air admitted. The bypass connection normally connects the return-air duct system with tbe apparatus casing between the condi tioner and the supply fan. Usually the bypass opening is sized to handle about 50 percent of the fan capacity where a variable bypass is used though extreme load variations 266 CHAPTER 19 1959 Guide may require a larger size. It is at times good design to locate areheaiing coil in the bypass connection to permit using some bypass air when heating is required. Since the rela tively high resistance of the cooling coil or spray is to be balanced by the heating coil and bypass connection, enough heating surface can be provided to raise the temperature of the bypass air to the point where the mixture of bypassed air and conditioned air will have-the required temperature. When a variable bypass is used, a damper working in oppo sition to the bypass damper should be placed across the face of the dehumidifier, for unless the resistances of the two are carefully halanrevl at all operating pomts, the proper mixtures of air will not be obtained. Outdoor air that has not been dehumidified should not be bypassed around a cool ing coil or spray dehumidifier if accurate control of the de livered relative humidity is desired. Where the bypass is made a part of the dehumidifier or conditioner and is lo cated on the top or tide of it, the retum-air connection should be arranged so that stratification of return air is in sured, baffles being provided to accomplish this purpose if necessary. When return-air and bypass air connections are taken off a return-duct system, it may be necessary to install a back-draft damper between the return-air connection and the bypass connection. When the bypass damper is at maxi mum opening it may be much easier for outdoor air to pass through the return damper, into the return-duct connection and through the bypass, than for return air to pass through the bypass connection into the fan. Air tends to take the path of [east resistance and, if the dehumidifier resistance is highland if the return duct resistances are low, this situation is apt to occur. A recirculating air fan, instead of a backdraft damper, may be required for this case, if the failure of return air to reach the dehumidifier or conditioner is a serious matter under reduced load conditions. LOCATION OF APPARATUS In general, the outdoor-air intake, preheaters, and returnair connections precede the conditioner, while tbe bypass, reheaters, and fan follow it. In the case of a blow-through system, where the fan is located ahead of the conditioner, the leakage of air at the conditioner is outward, instead of inward, and may be accompanied by water leakage. . The location of the complete apparatus assembly, includ ing the dehumidifier, will be dependent oq the type of build ing, spaces available, structural characteristics, etc. The type of conditioner used may limit the location under certain conditions. Where cooling coils employing chilled water or brine as the cooling agent are used, there are few limitations with regard to location other than those of pumping power, working pressures, piping costs, etc. Where spray dehumidi fiers are used, very definite limitations present themselves, and these may require certain extraneous equipment to make the system workable. If several spray-type dehumidifiers. are located on different levels, thus involving different water pressures, a surge or storage tank, to which the return water from each dehumidifier can be taken, is required. Should the water level in the pan of the dehumidifiers be low in relation to that of the surge return-water pumps will be required, and these pumps will have to be operated until the water supply lines are drained in order to prevent flood ing of the lower dehumidifiers. Where spray dehumidifiers are on the same level, equalizing lines between the pans may be required if a storage tank is not provided. It is exceed ingly important that watertight drained floors be provided under all overhead cooling systems, since water condensed out of the air generally will be present and may damage the interior finish of the rooms below tbe apparatus. All of the various pieces of equipment from the outdoor- air intake through the fan usually are connected together by sheet-metal casings. Frequently, the building structure or specially constructed walls or partitions may be used to form a portion of the casing. In any case the ratting or con nection must be sufficiently sturdy for the required duty. Sheet-metal work must be well braced not only to prevent vibration under pulsations in air flow, but also to withstand the abuse of normal usage. Casings should be braced wher ever access doors are installed, and all large panels should be adequately reinforced by structural steel. Accessibility for Service Each apparatus layout should be made with accessibility in mind. Where cooling convectors are used, space for re moving and repairing or replacing them should be provided. Adequate space should be provided for the servicing and replacement of eliminators. Filters must be so located that the proper cleaning, replacement, or routine servicing can be accomplished without difficulty. Free access to the bear ings of all moving machinery is a necessity. Provision should be marift for the replacement of any parte that are subject to wear, deterioration, or damage, such as filters, fanwheeis, motors, pump impellers, or heat transfer surface. CHAPTER 20 AIR DISTRIBUTION Definrffom, Standards for Satisfactory Conditions, Principles of Air Distribution Ventilating Jets m Air Distribution, Outlet Per formance, Outlet Types, Outlet Location and Selection, Directional and Volume Control, Return and Exhaust Intakes, Specific Applications. ORRECT air distribution is essential in warm air heat 13. Plague: A ceiling outlet in which the supply air impinges Cair tothinoagu,grohvoeamns,tyiulsantteisnmagtdi,sefaalivncetdorsraytihrc-eocnorednqidtuiiotirinoesdniqnregusausnlyttsiittyfemothfse.coaEnivrdeitinsionedadhgior1aer4iiczn.tosiDontnitafasfullpmsyleaiidrnt:epaAloalnlnrdesoisreu.ericteltesiot nodsfi.spcahraarlgleinl gplsautepsp,lyanadirisindevfalericotueds poorly distributed. 15. Primary Air: The air delivered to the outlet by the sup This chapter, deals with room air distribution only; the ply duct. transmission of air .through ducts is treated in Chapter 21, Air Duct Design. The objectives of this chapter are to: 16. Induction: The induction of room air drawn into an outlet by the primary air stream (commonly called aspiration). 1. Present the principles of room air distribution with a discussion of ventilating jets in air distribution. 2. Present general information on practical air distribution problems involving outlet performance, outlet types, location, selection, and outlet control. : 3. Illustrate the use of the basic concepts and of tbe practical experience gained in air distribution in making specific applica tions. - Further pertinent information on air distribution. will be found in Chapter 6, Physiological Principles; Chapter 12, Heating Load; Chapter 13, Cooling Load; Chapter 15, Unit Ventilators and Unit Heaters; Chapter 16, Unitary Air Con - 17. Entrainment: The entrainment of room air by the air stream discharged from the outlet (commonly called secondary air motion). 18. Total Air: The mixture of discharged air and entrained air. 19. Entrainment Ratio: The total air divided by the dis- . charged air. 20. Throw (Blow): The horizontal or vertical axial distance an air stream travels on leaving the outlet (grille) before the maximum velocity is reduced to 50 fpm. 21. Drop: The vertical distance, the lower edge of a hori zontally projected air stream drops between the outlet and the end ofits throw. ditioning Equipment; Chapter 18, Warm Air .Heating Sys 22. Rise: The converse of drop. tems; Chapter 19, Central Systems for Air Conditioning; Chapter 25, Sound Control; Chapter 44, Instruments,and Measurements; Chapter 48, Transportation Air Condition ing. v DEFINITIONS 23- Envelope: The outer boundary of an air stream moving at a perceptible velocity. 24. Spread: The divergence of the air stream in a horizontal or vertical plane after it leaves the outlet. 25. Diffusion: Distribution of air within a space by an out let discharging supply air in various directions and planes. The following definitions referring to air distribution equips ment have gained general acceptance. 26. Radius of Diffusion: The horizontal distance from the "diffuser outlet to the perimeter of the space, within which air motion in the occupied zone is reduced to 50 fpm maximum. 1. Supply Opening or Outlet: Any opening through which air 27. Outlet Velocity: The average velocity of air emerging from is delivered into a space which is being heated, cooled, humidi ' the outlet, measured in the plane of the opening. fied, dehumidified, or ventilated. 28- Terminal Velocity: The average air stream velocity at 2. Exhaust Opening or Return: Any opening through which the end of the throw. j air is removed from a space which is being heated, cooled, humidified, dehumidified, or ventilated. 29. Temperature Differential: Temperature difference be tween primary and room air. ' 3. Outdoor Air Opening: Any opening used as an entry for air from outdoors. 4. Damper: A device used to vary the volume of air passing 30. Temperature Variation: Temperature difference between points of the name space. through a confined cross-section by varying the cross-sectional area. STANDARDS FOR SATISFACTORY CONDITIONS 5. Grille: A covering for any opening and through which air passes. ' 6. Register: A grille equipped with a damper or control valve. 7. Free Area: The total minimum area of the openings in the air outlet or inlet through which air can pass. . Hie object of air distribution in warm air heating, ventilat ing, and air-conditioning systems is to create in the occupied zone of the conditioned room (floor to 6 ft above floor level) the proper combination of temperature, humidity, and air 8. Core Arta: The total plane area of that portion of a grille, included within lines tangent to the outer edges of the outer openings through which air can pass. ` 9. Free Area Ratio: The ratio of tbe free area to tbe core area. 10. Coefficient of Discharge: Ratio of area at vena contracta to area of opening. 11. Aspect Ratio: The ratio of length to width of an opening or core of a grille. 12. Vane Ratio: The ratio of depth of vane to minimum width between two adjacent vanes. - motion. To obtain comfort conditions within this zone, stand ard limits have been established as acceptable effective tem peratures. This term comprises air temperature, motion, humidity, and their physiological effect on the surface of the human body. Any variation from accepted standards of one of these elements may result in discomfort to the occupants.' Tbe same effect may be caused by lack of uniformity of con ditions within the space or by excessive fluctuation of condi tions in the same part of the space. Such discomfort may 267 268 CHAPTER 20 1959 Guide Arise due to excessive room air temperature variations (hori zontally, vertically, or both), excessive air motion (draft), failure to deliver or distribute the air according to the load requirements at the different locations, or too rapid fluctua tion of room temperature or air motion (gusts). With reference to permissible room air motion it is not possible to establish a specific standard covering the entire complex problem of air distribution. Velocities less than 15 fpm generally cause a feeling of air stagnation, whereas velocities higher than 65 fpm may result in a sensation of draft. Air velocities of 25 to 35 fpm in the occupied zone are . most satisfactory, but air motion of 20 to 50 fpm will usually be acceptable, with the lower values used in cooling applica tions, and the higher values in heating applications. The permissible air motion depends to some degree on the geo graphic location of the air-conditioning installation. In addi tion the noise level created by the introduction of supply air should be kept within acceptable limits, and streaking or smudging of walls or ceilings should be prevented. Reference should be made to Chapter 6, Physiological Principles, for information on effective temperature and com fort lines, and to Chapter 25, Sound Control, for acceptable room noise levels and noise generated by air outlets. Material in Chapter 51, Control of the Industrial Environment, and Chapter 50, Process and Product Air Conditioning, deals with the health, safety, and efficiency of workers, and with tem perature and humidity requirements for products and manu facturing processes, respectively. PRINCIPLES OF AIR DISTRIBUTION Conditioned air is supplied to air outlets at temperatures and velocities which differ greatly from those in the occupied zone of the .room. Proper air distribution, therefore, calls for (1) entrainment of room air by the primary air stream outride of the zone of occupancy in order that air motion and tem perature differences will be reduced to acceptable limits before the air enters the occupied zone, and (2) counteraction of the natural convection and radiation effects within the room. The complexity of practical room air distribution problems is due to innumerable variations in building construction, system design, and operating requirements, and makes the exploration of the basic character of air distribution impera tive. The theory of room air distribution is not complete but a considerable fund of knowledge supported by experimental guidance is available for the solution of many air distribution problems. In particular, research at the ASHAE Research Laboratory and at Case Institute of Technology have ad vanced considerably the fundamental knowledge on ventilat ing jets in air distribution. Also, a comprehensive survey of the literature relevant to air distribution problems was made at tiie ASHAE Research Laboratory and is an indispensable and timesaving tool for every researcher in air distribution. (Refer to Bibliography: ASHAE Research laboratory.) The cooperative research program in air distribution at Case Institute of Technology was started in 1937. The early research dealt with methods of measurements and the avail able instruments; next the basic flow patterns of free round and rectangular jets in an open space were studied. A third phase was concerned with diffusion rates and characteristics of free jets from the more complex types of outlets, such as grilles with guide vanes, narrow slots, perforated panels, plaques, and round ceiling diffusers. The latest phase has dealt with air movement produced by non-isothermal jets, especially in confined spaces, and has included experimental work in cold-wall rooms during heating and warm-wall rooms during cooling. (Refer to Bibliography: Cooperative Research at Case Institute of Technology.) . VENTILATING JETS IN AIR DISTRIBUTION A surprising similarity between the shape of jets exists at a short distance from the outlet face, whether the outlet is round, rectangular, grille-like, or a perforated panel. The jet discharged from a round opening forms an expanding cone, whereas jets from rectangular outlets rapidly pass from rec tangular to elliptical cross-sectional shape at a short HUtAnro from the outlet face, and then to circular shape, at a rate depending primarily on the aspect ratio. Even in the case of wide-angle grilles and angular outlets, the similarities are such as to permit the same analysis of performance. For many conditions of jet discharge, therefore, it is posable to analyze jet performance, and to determine (1) the angla of divergence of the jet boundary, (2) the velocity patterns along the jet axis, (3) the velocity profile at any cross-section in the zone of maximum engineering importance, and (4) the entrainment ratios in the same zone.1 In using the data presented in this section, .however, the following must be kept in mind: 1. The method of finding jet velocities is based upon several approximations and, therefore, the two recommended equa tions must be used with caution for extreme axial and radial distances. . 2. TEte characteristics of the low-velocity regions of ventilat ing jets are not yet well understood. Neither for axial nor radial jets are the effects at various Reynolds number fully known. 3. The quantitative treatment of the forces that govern room air distribution problems has been limited, and nan-isothermal conditions involving buoyant forces have not yet been fully explored. For equations describing the performance of non-isothermal jets resulting from the air distribution research at Case Insti tute of Technology see References 2 and 3. (Refer also to Bibliography: ASHAE Cooperative Research at Kansas State College.) 4. Most investigations have been concerned with /r jets, whereas air streams in practical room air distribution are not free streams but are influenced by walls, ceilings, floors, and obstructions. (Refer to sections on Effect of Warn and Ceilings and Room Air Motion.) ' Angle of Divergence The angle of divergence is very definite close to the outlet face, but the boundary contours are somewhat billowy and are easily affected by external influences. Here, as in air dis tribution generally, room air movement is replete with local eddies, vortices, and surges, which are manifestations of un balance in the forces acting within the air stream. These in ternal forces govern the air motion, yet they are extremely delicate.4 ' . Measured angles of divergence (spread) for discharge into large open spaces have usually ranged from 20 to 24 deg with an average of 22 deg. Coalescing jets for closely spaced mul tiple outlets expand at somewhat smaller angles, averaging 18 deg, and jets discharging into relatively small spaces show even smaller angles of expansion.4 Tests indicate that in cases where the outlet area itself is'small compared to the dimensions of the space normal to the jet, the jet may be considered free as long as x < usVAi where , X *= distance from face of outlet, feet. Ag -- cross-sectional area of the confined apace, square feet.' Air- Distribution 269 Four Zones in Jet Expansion In analysing the performance of jets, four major zones can be distinguished. They may be roughly defined in terms of the maximum or centerline velocity existing at the cross section being considered: Zone t: A short zone, extending about 4 diameters or widths from the outlet face (or vena contracts for orifice discharge), in which the velocity of the air stream remains prac tically unchanged. Zone t: A transition zone, extending to about 8 diameters for round outlets, or for rectangular outlets of small aspect ratio, over most of which maximum velocities vary inversely as the square root of the distance from the outlet. For rectangu lar outlets of large aspect ratio, this zone is elongated and ex tends from about 4 widths to a distance approximately equal to the width multiplied by four times the aspect ratio. Zone S: A long zone, of major engineering importance, in in which the maximum velocity varies inversely as the distance from the outlet. This zone is often called the zone of fully es tablished turbulent fioxo and may be 25 to 100 diameters long (or equivalent diameters of equal areas), depending on the shape and area of the outlet, the initial velocity, and the dimensions ' of the space into which the outlet discharges. Zone 4- A terminal zone in which, in the case of confined spaces, the maximum velocity decreases at an increasing rate, or, in the case of large spaces free from wall effects, the maxi mum velocity decreases rapidly-in a few diameters to the ve locity range below 50 fpm which is usually regarded as still air. Centerline Velocity in Zone 3 Research has shown that maximum or centerline velocities in Zone 3 of straight flow isothermal jets can be determined with good engineering accuracy from v, kd, kVa, xr, " " x (1) V- g'Q x " xVXt K'Q _______ " Xy/At XCjX R/. (2) (2a) Table 1.... Recommended Values of the Centerline Velocity Constant K or K' (Sm Equation I) 1 Kf - Type of Ootfoi y - V. - Vt - V, 500 to 2000 to 500 to 2000 to 1000 10,000 1000 10,000 Free Openings Round or Square ' 5.0 6.2 5.7 7.0 Rectangular, large aspect 4.3 5.3 4.9 6.0 -- --Tatio (<40) Annular slots axial or radial* 3.9 4.8 Grilles and Grids Free area 40% or more 4.1 5.0 4.7 5.7 Perforated Panels . Free area 3 to 5% 2.7 3.3 3.0 3.7 Free area 10 to 20% . 3.5 4.3 4.0 4.9 * For ndialdote om X/B instead of Xf(A)it*. B tbeheigbt or widthof tlw slot. StU: K and K' are laden* <d Ion ia axial kinetic eneixy. Interpolate u re quired- Departure* from maximum value indioto tone* in first and nni when compared with tbs i*t from a rounded-entrance, circular ooszle. Fig. 1... .Effective Diameters for Round and Rectangular . Openings (Plenum Approach) where V. centerline velocity, feet per minute. y V, _ w _ *= average initial velocity at discharge ti X A/a from open-end duct or across contracted stream at vena contracts of orifice or multiple-opening - outlet, feet per minute. ve nominal velocity of discharge based on the core area, feet per minute. Ce - coefficient of discharge (usually between 0.65 and 0.90). Ru = ratio of free area to gross (core) area, X - distance from face of outlet, feet, K and K' * porportionality constants, with K' " 1.13 K. D, * effective or equivalent diameter of stream at discharge from open-end duct or at a con tracted section, feet. At At X C* X Rf = effective area of stream at discharge from an open-end duct or at a con tracted section, square feet, measured gross (core) area of outlet, square feet. . Q - discharge from outlet, cubic feet per minute. Equation 1 is nondimensional and requires only that con sistent units be used, as in the above nomenclature. Values of K and K' are listed in Table l.1-4 Low velocity test results, in the range V, < 150 fpm, indi cate that the normal values of K and K' should be reduced about 20 percent for V, = 50 fpm, as used in later Equation 4b for throw. Fig. 1 gives the effective diameter D0 in inches for single openings and includes the coefficient of discharge.7 Similar values for grilles are available in the literature or can 270 CHAPTER 20 1959 Guide be experimentally determined. Values of C, and Rf, are required for determining V#, Do, and At for orifice-type and multiple-opening outlets, and should, therefore, be included in catalog data of these outlets. In- the case of multiple-opening outlets and annular-ring outlets, the streams coalesce into a solid jet before actual jet expansion takes place. This coalescence affects the experimen tally determined proportionality constants K or K' and ac counts for some of the divergence in reported values for simi lar outlets. Centerline Velocities in Zones 1 and 2 Experimental evidence indicates that in Zone 2 where ' H% ** width of jet at outlet or at vena contracta. Approximately the same values of K' apply as for Zone 3 expansion from axial outlets. In Zone 1, the ratio F./F* is constant and equal to the ratio of the center velocity of the jet at start of expansion to the average velocity, ranging from approximately 1.0 for roundedentrance nozzles to about 1.2 for straight pipe discharge, but with much higher values for diverging-discharge outlets. Determining Centerline Velocities To permit correlation of data from all four zones, centerline velocity ratios are plotted against distance from outlet in Pig. 2 in accordance with the basic relation of Equation 2, and a nomogram for calculating the parameters . X and V, V( from X and vz F, V, through Rf* and C, is given in the same illustration. The variation of the centerline velocity ratio with distance from outlet, or more properly, from start of jet expansion, is also shown on Pig. 2 for Zones 1 and 2. F,/F0 is plotted against XfUt and, for a range of aspect ratios, against X/VA for the single value of K' -- 7.0. Values of F./Vo for other values of K' may be obtained by direct proportion ing of \/K' to >/7.0. Air Distribution Straightflow Turbulent Jets The following Example 1 which is solved on Pig. 2 will illustrate the. use of the chart. - Example 1: A grille has a core area 12 in. x 18.75 in., ft/. = 0.90, C, ** 0.80, and K' = 5.0. Find F, (velocity through core area) when F, is 50 fpm for throw of 50 feet (X = 50). Solution: 12 X 18.75 1.56 sq ft V, Vr 0.106 ____ ve ~ VtiCdRfJ " 0.80 X 0.90 " 0,147 For V, - 50, 50 V. 0.147 340 fpm. The quantity of air discharged is then, Throw Q = VJL, - 340 X 1.S6 - 530 cfm. - Equation 2a can be used to determine the throw X of an outlet, if tite discharge volume and the center velocity are known. ' .. K< Q X F. VAc X C, X ft/. (4) or, if Z Vc, x ft/. X Q v.'zvx,; (4a) The maximum throw L is usually defined as the distance from the outlet face where the centerline velocity is 50 fpm. Therefore, for F, = 50 fpm. L-X C 50 ZV~A* (4b) 271 Velocity Profiles of Jets In Zone 3 of both axial and radial jets, the velocity distri bution may be expressed by a single curve (Pig. 3) in terms of dimensionless coordinates, and this sanw curve ^ used as a good approximation for adjacent portions of Zones 2 and 4. Experiments have shown that temperature and density differences have but a small effect on cross-sectional velocity profiles. . Velocity distribution in Zone 3 can be expressed by the Gauss error-function or probability curve which is approxi mated by a simple equation tiring common logarithms Ct;)'-""*=? <*> where - r = the radial distance of the point under consideration from the centerline of the jet. rt.s = the radial distance in the same cross-sectional from the axis to the point where the velocity is half the centerline velocity. (F -> 0.5 F,.) F, the oenterline velocity in the same cross-sectional plane, feet per minute. F - the actual velocity at the point being considered, feet per minute. Experiments show that the conical angle for 0.5 V, and r9.t is approximately one-half of the total angle of divergence of a jet. The velocity profile curve for one-half of a straightflow turbulent jet (the other half being a symmetrical dupli cate) is shown in Pig. 3. For multiple-opening outlets, such as grilles, or perforated panels, the velocity profiles are simi lar, but tire angles of divergence are smaller. Radial Jets In the radial jet the cross-sectional area at any Histone* from the outlet varies as the square of this Hist/mr*, the wanTM as for an axial jet. Experiments have shown that the centerline velocity gradients and the cross-sectional velocity profiles are similar to those of Zone 3 of *TMl jets and that the angl*? of divergence are about the same. In using Fig. 2, X/H should be used as abscissa instead of X/\/~A. Jets from ceiling plaques have the same form as one-half of a free radial jet. The jet is wider and longer th.n a free jet, with the maximum velocity close to the wall. This is demon strated in Fig. 4 which also indicates that under the conditions shown the width of the slot between ceiling and plaque NOZZLE OOO '' '~~Y'' y '' -1;------------ SKAOCO AREAS REPRESENT kCASURED VELOCITY PflOPR.CS Sy3" NOZZLE 130 *7--- ------14* PLAQUE 262 CPU pm**'' " f* -L-- Rg. 4... Air Jets from a 14-in. Ceiling Plaque for Two Slot Widths with Same Rate of Row 272 CHAPTER 20 1959 Guide little effect on the jet pattern or velocities at some distance from the plaque.1 . For a equation for radial flow outlets resulting from the air distribution research at Case Institute of Technology see Jet Velocities from Radial Flow Outlets, by Alfred Koestel (ASHAE Transactions, Vol. 63, 1957, p. 505). Discharge from a Long Slot When a long slot receives its air supply from one end only, the important d<*rign factor is the ratio of the area of the slot to the area of the supply duct, and both the air stream profiles and the duct pressure requirements are determined by this Area is Increased K\\\\\\\\\\\\\\ fig. 6.... Uniform Air flow from a Slot Supplied by a Tapered Duct fig. 7.... Jet Velocity Patterns for a Square Outlet Discharging along Wall or Ceiling ratio.8 Fig. 5 showB the changing profile as the slot area is increased for a rounded entrance sioi (C< - 0.93) with con stant duct cross-section. The air discharge from a slot in a tapered duct will be uni form (Fig. 6) for a relationship between discharge angle and ' slot-duct dimensions* cot tf = --~ At (6) where 9 TM discharge angle, degrees. A, *= slot area, square feet. At -- duct cross-sectional area at upstream end, square feet. Cd coeffcient of discharge. Perforated Panels When air is discharged from perforated panels of relatively large the constant velocity core formed by the coales cence of the individual jets extends a considerable-distance from the panel face. In this Zone I region the proportionality constants K and K' do not apply. Therefore, the proportion ality constants given in Table 1 should be used only when the ratio (Distance from panel/\/Panel area) is larger than 5. When the ratio is less than 5, the equation V, - Vo-1.2%/C, X Rf. (7) should be used for estimating centerline velocities.1* Effect of Walls and Ceilings Jets discharging parallel to a wall with one edge of the out let coinciding with the wall, take the form of one-half of an axial jet discharging from an outlet twice as large, similar to radial jets from ceiling plaques. Entrainment takes place practically only along the surface of a half cone and the maximum velocity remains close to the wall.1 (See Fig. 7.) Values of K and K' ore approximately those for a free jet multiplied by y/2, that is to say, the normal maximum of 7.0 for K' for free jets becomes 9.9 for a mmilAj jet adjacent X to, and discharged parallel to, a wall, and in Fig. 2, --.-- V 2A %. should be used in place of --7= Va, When a jet is discharged parallel to, but at some distance from a wall, its expansion in the direction of the wall ^re duced and entrained air must be obtained by recirculation from the jet itself instead of from ambient air.*-u The jet expands normally to within a short distance from the waU, which nearer to the outlet only affects velocity distribution in the outer shell of the jet, but further on affects center line velocities. This happens at some distance from a plane where the jet outline becomes parallel to the wall, and where tiie jet enters its fourth or terminal zone. Few engineering data are available on this important phase of jet expansion.* Effect of Resistance on Return Path of Jet Air Laboratory experiments on jets visually involve recirculated air with negligible resistance to fiow on the return path of the jet air. Experience and experiments in tunnels of small cross sectional area in mines, where considerable resistance is offered to the return fiow of jet air to outlets, show that the expansion of the jet terminates abruptly at a distance that is independent of velocity of discharge and but slightly affected by size of outlet. Such distances are determined primarily by size and % 9 t i. Air Distribution 273 length of return path. In a long 5 ft x 6 ft tunnel, a jet may not travel more than 25 ft whereas in a relatively short open ing, 25 hv fiO ft. it may travel more than 250 ft. Few engineer ing data are available on this phase of jet expansion but it can be of great practical importance.* Entrainment Ratios Equations for the entrainment of circular jets and of jets from long slots have been mathematically derived.12 They are: For third zone expansion of circular jets, Qt _2 X Q K' ->/a (8) (8a) where Q, *= total volume flow rate at distance X from face of out let, cubic feet per minute. - Qt B discharge from outlet, cubio feet per minute. X -- distance from face of outlet, feet. K' = proportionality constant. A TM effective area of stream at discharge from an open- end duct or at a contracted section, square feet. ' St = width of slot, feet. Equations 8 and 8a have been used in plotting Fig. 8 for entrainment ratios. - OUTLET PERFORMANCE The air distribution research sponsored by the American Society op Heating and Air-Conditioning Engineers has proved that the phenomena of room distribution are amenable to scientific research and rational interpretation, and has now reached a stage where a definite technique of ex perimentation in combination with semi-empirical theories can be of great help in the design of air outlets. Practical room air distribution, however, is still predomi nantly an art, where decisions depend on isolated tests and judgments must be based on the accumulated experience of the behavior of outlets in the laboratory and in the field. Manufacturers' literature is available to provide data for the performance and application of various outlets. In designing a satisfactory air distribution-system, the engineer must make use of this material, and weigh the different factors of the outlet performance which place considerable limitations on his proceedings. A short discussion follows regarding some of these factors which are: (1) jet pattern, (2) capacity, (3) temperature differential, (4) room air motion, (5) permissi ble noise level, and (6) smudging. Jet Pattern Refer to section Ventilating Jets in Air Distribution for a general discussion of the jet pattern. In selecting the throw and drop of outlets the following considerations are impor tant: (1) throw, (2)' effect of vanes, (3) effect of type of outlet, and (4) drop. 1. Throw. The throw of * wall outlet must be sufficient to produce satisfactory conditions over the area to be condi tioned. Underblowing may cause heated air to rise too rapidly above the occupied zone and thus create excessive vertical temperature variation (stratification); in cooling operation it may cause cold air to drop into the occupied zone before supply and room air are mixed sufficiently, and thereby cre ate a condition of acute discomfort (draft). On the other hand, overblowing will result in objectionable downdrafts from any surface the primary air stream may strike. On the average, it is considered most practicable to select a throw which is three-fourths of the distance toward an ex posed wall or window, as shown in diagram A of Fig. 9. How ever, structural characteristics, mounting height of outlet, temperature differential, and resultant'drop or rise, or loca tion of greatest heating or cooling loads strongly affect the selection of the optimum throw. In spaces with beamed ceil ings, the outlets should be located below the bottom of the lowest beam level, and preferably low enough so that an up ward or arched blow may be employed. The blow should be arched sufficiently to miss the beams and, at the same time, in such a maimer as to prevent the primary or induced air stream from striking furniture and obstacles, and producing objectionable drafts. 2. Effect of Vanes. Vanes affect grille performance if their depth corresponds at least to the distance between the vanes. If the vane ratio is less than unity, effective control of the air. stream discharged from the grille by means of the vanes is impossible. If it is higher than two, further improvement is slight. " A grille discharging air uniformly forward (vertical vanes in straight position), will have a spread of 14 to 24 degrees, depending on type of outlet, duct approach, and discharge velocity. Turning of the vanes will influence the direction and the threw of the discharged air stream. A grille with diverging vanes (vertical vanes with uniformly increasing angular deflection to a maximum at each end of 45 deg) will have a spread of approximately 60 deg and the throw will be reduced considerably. With increasing diver gence the quantity of air handled by the grille for a given duct static pressure will decrease. ' A grille with converging vanes (vertical vanes with uni formly decreasing angular deflection) will have a slightly higher throw than a grille with straight vanes, but the spread will be the same for both settings. The air stream will con verge slightly for a short distance in front of the outlet, and then spread somewhat more than the air discharged from a grille with straight vanes. In addition to vertical vanes which normally spread the air horizontally, horizontal vanes may be used to spread the air vertically. However, spreading the air vertically entails the risk of hitting beams or other obstructions, or of blowing primary air at excessive velocities into the occupied zone. 3. Effect of Type of Outlet. Ceiling diffusers distribute the air with a horizontal spread of 360 deg and also have a down ward air motion. Therefore, both throw (radius of diffusion) and mounting height are important and interdependent fac tors. Due to the 360 deg spread, the rate of induction is higher and the throw shorter than that for a wall grille handling the some air quantity at the same outlet velocity. Therefore, ceiling diffusers will frequently permit the use of higher air velocities than wall outlets, and consequently may be sized smaller to handle the same air volumes. If ceiling outlets are installed flush with the ceiling, impingement of the air stream along the railing surface restricts induction of secondary air, and the throw is increased approximately 40 percent above that of an unrestricted air stream. (Refer to Radial Jets and Effect of Walls and Ceilings in section Ventilating Jets in Air Distribution.) Slotted outlets, due to their high aspect ratio, have higher induction than comparable round or square vaned outlets of 274 CHAPTER 20 - 1959 Guide equal area handling the same air quantity, and their throw is shorter. (Refer to Discharge From a Long Slot in section Ven tilating Jets in Air Distribution.) The perforated panel is an excellent device for producing a large diameter stream with a uniform velocity across its entire area. Although this type of outlet can handle the great est amount of air in proportion to room size, jet velocities must be kept low. (Refer to Perforated Panels in section Ventilating Jets in Air Distribution.) For all types of catling outlets the following considerations should be noted: (1) if the temperature of the supply air is below that of the room, it should be thoroughly mixed with the room air before it enters the occupied zone; (2) air slightly above room temperature will usually be properly dis tributed by outlets selected for cooling; and (3) if the tem perature of the supply air is substantially higher than that of the room, it should be projected downward in a broad di verging pattern to avoid stratification and to obtain proper mixing and controlled air flow. 4. Drop. Hie air discharged from a wall outlet should not reach the occupied zone until the velocity has fallen to about 50 fpm. Therefore, the outlets should be located high enough Fig. 9.... Throw of Well Outlets for the air stream at the termination of. the throw to be not less than 5 or 6 ft above the floor level, or in other words, the drop should.not be more than the difference between mount ing height and zone of occupancy (see Diagram A of Fig. 9). As illustrated in Diagram B of Fig. 9 the maximum permissi ble throw for a given ceiling height may be obtained'by lo cating the outlet low on the wall, arching the blow, and sweeping the air across the flat area. The air, as it traverses, will adhere to the ceiling. The objection to this method is the possible streaking of the ceiling with dirt. Capacity The quantity of air to be handled is determined by the heating, cooling, or ventilating requirements as given in Chapters 11 Infiltration and Ventilation, 12 Heating Load, and 13 Cooling Load. Manufacturers' rating sheets are usu ally consulted for selection of the proper number, size, and type of outlets for a given air quantity. The basis of rating should be carefully noted to make certain that resulting velocities are suitable for the application. Temperature Differential . The temperature difference between supply and room air is highly important, because temperature control in the con ditioned room is strongly affected by this difference. The greater the temperature differential, the greater the change in room temperature for a given change in the heating or cooling load. The use of outlets which cause a large amount of room air to be. mixed with the supply air, permits the use of greater temperature differentials. (Refer to section Air Quantity and Temperature Differential, Chapter 19, Central Systems for Air Conditioning.) Room Air Motion .. To achieve a constant air motion in the occupied zone with out exceeding acceptable velocity limits is one of the most important problems in air distribution. Some of the factors which may cause air motion to exceed these limits are: ex cessive air discharge velocities; high air volume per cubic foot of space (often referred to as number of air changes per hour); premature drop of cold air into the occupied zone; overblow causing spilling of high velocity air into the occu pied zone; heating in severe climates by means of downward projection of hot air. These factors will not affect equally the various designs and types of air outlets, and their effect will also depend on the temperature differential, the mounting height of the outlet, and other circumstances. For instance, certain outlets will handle safely more air per cubic foot of space at higher discharge velocities than others, and down ward projection of air may sometimes even be -necessary if the supply air temperature is substantially higher than the - room temperature. (Refer to section on Throw.) Sometimes excessive air motion may be encountered in correctly designed air distribution systems due to drafts oc curring, if stairways or exit doors are left open, or if windows are opened when design of system requires that they be closed. Discomfort is frequently attributed to drafts when it is actually due to too low room temperature. This may occur during the heating as well as the cooling season. Systems de signed for heating and ventilation only may easily cause complaints of drafts when cooling is added. The following papers give useful information with regard to room air motion: Room Air Distribution Research for Year 'Round Air Conditioning, Part I--Supply Outlets at One High Sidewall Location, by S. F. Gilman, H. E. Straub, A. E. Hershey, and R. B. Engdahl (ASHVE Transactions, Vol. 59, 1953, p. 151); Room Air Distribution Research For Year Hound Air Conditioning, Part II--Supply Outlets at Three Floor Locations, by H. E. Straub and S. F. Gilman (ASHVE Transactions, Vol. GO, 1954, p. 249); Perform ance and Evaluation of Room Air Distribution Systems, by Alfred Koestel and G. L. Tuve (ASHAE Transactions, Vol. 61, 1955, p. 533); Air Velocities in Two Parallel Ventilating Jets, by Alfred Koestel and J. B. Austin, Jr. (ASHAE Trans actions, Vol. 62, 1956, p. 425). Permissible Noise Level The increase of the noise level caused by an outlet is primarily a function of its discharge velocity and its size. The maximum acceptable noise level in a space may dictate completely the selection of the permissible outlet velocity. In addition, however, noise may be caused by excessive re striction of the free outlet area due to outlet design, by unnecessary turbulence due to one-sided air flow through the outlet, or by impingement of high velocity air on sharp edges. . The origin of excessive noise may be spotted by removing the outlet without stopping the air supply. If noise is still evident, other elements of the air-conditioning system or entirely different sources are at fault. High-pitched, rushing noise indicates that the duct system or excessive velocities in the duct are the cause, low-pitched rumbling noise points to the mechanical equipment of the air-conditioning plant. When very high duct velocities are used, sound-absorbing lining or special acoustical filters (sound traps) must be '*j Air Distribution 275 provided. High-pressure or high-velocity outlets for multi room and other buildings are equipped with a special pres sure reduction and sound attenuation box. (Refer to section Types of Air Outlets.) ` - For a general discussion of permissible room noise levels and air supply outlet noises, refer to Chapter 25, Sound Control. Smudging All air outlets have their particular smudging problems which have been studied by various investigators but cannot yet be considered solved. Smudging is due to dirt in the room air and in the air discharged by the outlets. Although the primary air may be carefully filtered, finm.ll particles of dirt and dust will not be captured by mechanical filters, ' and may finally be deposited on the walls or ceiling. With ceiling outlets, dirt streaking may be minimized by carefully controlling the discharge of the outlets, or by the use of special deflecting plates or anti-smudge rings. With wall outlets, dirt streaking may be minimized by preventing direct impingement of the air on any ceiling or room surface. Floor outlets may be objectionable as dirt collectors. TYPES OF AIR OUTLETS Air supply outlets for commercial, industrial, nrl resi dential applications are either side-wail- or ceiling-type out lets. In homes, baseboard and floor type outlets are also used. (Refer to Chapter 18, Warm Air Heating Systems.) As a great variety of outlets of various design are available in these four types, the final selection of a supply air outlet depends to a large degree upon the specific problems of the air distribution system to be used. . In addition to the comments which follow on use and ap plication of outlets, reference should also be made to sections Outlet Location and Selection and Specific Applications." Wall Outlets Side wall outlets in general use are (1) perforated grilles, (2) fixed and adjustable bar and vane grilles, (3) registers, (4) wall diffusers, (5) slotted wall outlets, and (6) high- pressure or high-velocity wall outlets. 1. Perforated Grilles. These grilles have a small vane ratio and are not adjustable. They are useful primarily where di rectional air flow is unnecessary, and for applications where the grille size can be increased in order to provide the re quired free area. - 2. Fixed and Adjustable Bar and Vane Grilles. Grilles with- fixed bars or vanes are used for wall, floor, or baseboard applications when the performance is not critical or can be adequately predicted. Adjustable grilles are equipped with either vertical or horizontal adjustable bars or vanes or both, and are used where proper control of air motion is essential. Vanes should be designed for quiet operation. 3. Registers. Grilles equipped with dampers or adjustable valves for controlling volume distribution of the supply air are called registers. 4. Wall Diffusers. These outlets incorporate design fea tures originally developed for ceiling outlets, and therefore make use of semi-conical or semi-pyramidal guide vanes instead of the straight vanes of the conventional side-wall outlet. In warm air perimeter systems they are used to blanket the outside wall with the warm supply air. 5. Slotted Outlets. These outlets are available in a great variety of designs, consisting either of elongated outlets with perforation?, or flat outlets with a number of long narrow slots or a single narrow slot, or straight long outlets with one long slot or diffusing vanes. Due to their high aspect ratio, slotted outlets have higher entrainment th^.n comparable round or square vaned outlets of equal area and conse quently, the throw is reduced. (Refer to Discharge from a Long Slot in section Ventilating Jets in Air Distribution.) Slotted outlets are particularly useful in connection with the linear design motif in architecture, for applications where it is desired to merge air outlets unobtrusively with the room decoration. They may be used for either ceiling or wall air distribution, including the so-called under-the-window- ap plication.. In all applications, capacity limitations, proper duct approaches, and correct balancing of slotted outlets must be carefully considered, as correction after installation is difficult. 6. High-Pressure or High-Velodty Outlets. Ejector nozzles operate at high static pressure and convert this pressure into velocity presure with resulting high induction of room air. They are mainly used for industrial process installations, particularly drying. Another type of ejector nozzle is some times referred.to as a louver nozzle and has a 45 to 90 deg elbow, which can be rotated similarly to a universal joint about an axis perpendicular to the surface to which it is fastened. These outlets give a considerable degree of ad justability and are, therefore, useful for spotcooling in con fined spaces. High-pressure or high-velocity air-conditioning systems installed in multi-room and other buildings, use very high velocity and pressure so that the size of the ducts can be reduced. This in turn requires the use of high-pressure or high-velocity air outlets which reduce the velocity and pres sure and attenuate the sound to predetermined values at the point where the air is discharged. It is also possible, of course, to use high velocity only in' part of the system, for example in the main trunk ducts, and conventional velocities in the branch ducts. Special high-pressure control units are then installed at the end of the main duct, and the air is discharged through conventional air outlets in the various spaces of the building. Various high-pressure or high-velocity outlets of different design, but usually consisting of a pressure reduction and sound attenuation box and a grille or diffuser, have been developed for high-velocity systems and are described in the literature of the manufacturers. These outlets may be used in the ceiling or in the wall of the air-conditioned space, including under-the-window installation, or in the ceilings of corridors. Refer to Unitary-Central Systems for multi room buildings in Chapter 19, Central Systems for Air Conditioning, and to Design of High-Velocity Ducts in Chapter 21, Air Duct Design. Ceiling Outlets .. Ceiling outlets in general use are (1) ceiling plaques, (2) ceiling diffusers, (3) high-pressure or high-velocity filing outlets, and (4) perforated ceilings and panels. 1. Ceiling Plaques. Plaques are of simple design. The air from the supply opening impinges on a plate is dis charged horizontally. Plaques are inexpensive, but as the air is not always uniformly discharged in all directions, proper control is difficult. 2. Ceiling Diffusers. Ceiling diffusers are round, square, rectangular, or slotted outlets of various Hprigns installed on, or parallel to, the ceiling. Performance of the different designs varies according to the principle employed. Some 276 CHAPTER 20 1959 Guide have qo internal induction, but hasten external induction by supplying air in multiple layers. Others have internal induc tion and distribute air over an entire hemisphere. The in duction effect is greatest in the direction of the axis of the outlet, and least in the plane perpendicular to the axis and located at the ceiling level. Thus the induction is greatest in the vertical direction where the least throw can be toler ated, and least in the horizontal plane at the ceiling where the greatest throw is desired. (Refer to section Slotted Out lets under Wall Outlets.) 3. High-pressure or High-velocity Outlets. Refer to text in section Wall Outlets. - 4. Perforated Ceilings and Perforated Panels. These de vices discharge air through perforations in the ceiling or part of the ceiling, and share with slotted outlets the ad vantage of unobtrusive appearance. In addition, sound absorbing materials may be used for the panels, or the panels may provide a luminous ceiling. Outlet air velocities may be kept low by using large out let areas, particularly in spaces with high room loads, high ventilating requirements, or low ceilings. Some perforated panels have a control plate frame which is inserted in the conventional ceiling duct. Supply air enters the plenum above the distribution plates through an adjustable air valve which can be set for varying air quantities and ve locities. (Refer to Perforated Panels in section Ventilating Jets in Air Distribution.) OUTLET LOCATION AND SELECTION The design of the air-conditioning plant for a building depends on the use to which the building is put, on its size, and its construction type. The design of the air transmission and air distribution system is influenced by the same factors. Therefore, these factors must be considered in designing the air transmission system, and in selecting the type and loca tion of the supply outlets. The location and selection of the supply outlets is further influenced by the interior design of the building, local sources of heat gain or loss, and outlet performance and design. Use, Size, Construction of Building The. use, size, and construction of a building are three factors which may influence or even govern the selection of a particular type of air distribution system, as is shown by the development of special high-pressure or high-velocity transmission and distribution systems for multi-room and other buildings. Generally, the physical details of the indi vidual rooms of a.building, such as height and shape, and the location of beams and other obstructions, influence the possible location of the supply ducts which in turn influences the outlet locations. The location of the supply ducts-- above the ceiling or within the walls, in a furred space above corridors, or in the conditioned room itself--has an important bearing, therefore, upon the design of the air distribution system. A particular method of air distribution may be highly desirable but it may be impossible to use it, due to the location of beams and masonry walls. . Refer to later section Specific Applications for a dis cussion of air distribution methods in various buildings. Heat Gain or Loss . Local sources of heat gain or loss promote convection currents or cause stratification, and may, therefore, de termine both the type and location of the supply outlets. Generally, the outlets should be located to neutralize any undesirable convection currents .set up by a concentrated heating load. If a concentrated source of heat is located at the occupancy level of the room, the heating effect may be counteracted by blowing the supply air toward the heat source, or by locating an exhaust or return grille adjacent to the heat source. The second method is more economical, as heat will be withdrawn at its source rather than be dissi pated into the conditioned space. Where lighting loads are heavy and ceilings relatively high (five watts per sq ft and above 15 ft), the outlets should be located below the lighting load, and the stratified warm air removed by an exhaust or return fan. An exhaust fan is recommended if the wet-bulb temperature of the air is above that of the outdoors, a return fan, if it is below this temperature. Either method reduces the requirements for supply air. If the lights are exposed, less saving can be realized than if they are enclosed, as a considerable portion of the energy is radiant. An important function of any supply outlet during winter heating is to maintain the temperature difference between the floor and ceiling at the lowest posable value. Since the air within a room is never so perfectly mixed that all of it is at exactly the same temperature, a certain amount of stratification is inevitable. Unless the supply outlets are properly selected and located, the temperature difference will be large enough to result in discomfort to the occupants. The proper selection and location of outlets is particularly difficult for rooms with large windows and exposed wall areas. Heat is lost primarily through these areas, and room air in contact with these surfaces is chilled and flows downward, causing drafts near the exposed surfaces and floor. This condition can best be prevented by locating the air ' outlets under the windows, by discharging warm air across the exposed surfaces, or by providing supplementary radia tion under the windows, in addition to the wall or ceiling air distribution outlets. This solution must be used for comfort installations in northern latitudes (outdoor. temperatures below 40 F), when the building walls are uninsulated or single-glass windows are used. In buildings located in regions where winter heating is a minor problem, high induction by ceiling or wall outlets may be employed to mix properly the entire room air with the supply air and to prevent downdrafts along the exposed surfaces. In northern latitudes, this solution can only be used if the buildings have double-glass windows and insulated walls, as otherwise the induction effort required for neu tralization of the downdrafts is so great that the air motion in the room exceeds comfort limits. Where comfort condi tions are not critical as in factories for heavy maunfacturing, warehouses, etc., satisfactory results with high induction outlets can be obtained even in cold climates. For uninsulated walls and glass areas in these buildings some supplementary heating is often valuable. Wall diffusers, direct radiation, or warm panels will satisfy these requirements for supple mentary heating. The location of exhaust or recirculating air openings at the* base of large areas of glass is sometimes effective in reducing downdrafts into the occupied space. Great care should be exercised in the use* of supplyexhaust air outlets for heating in northern latitudes when considerable exposed wall and window surfaces are involved. In such cases additional radiation is usually required. When the system is used for ventilating only during the heating season, direct radiation should be regulated to provide heat until room and outside temperature are balanced. To avoid Air Distribution 277 stratification, it is advisable to operate the fan continuously and to limit the temperature differential by supplying air at a high rate of change per hour. Outlet Performance and Design Outlets should perform efficiently and conform to the esthetic appearance of the room. The physical appearance of air outlets has been highly influenced by modem interior design, and to meet the demands of architects and engineers. Outlets to be installed flush with the ceiling and outlets with built-in lighting as well as square and linear-type outlets have been developed in the past years. Unear-type outlets and perforated ceilings or panels have the advantage of un obtrusive appearance. ' Procedure for Outlet Location and Selection In determining outlet location and selecting the type of outlets, it is customary to proceed as follows: 1. Study the plan of the building and note the amount of air to be supplied to each room. (For computation of the required air quantity for heating and cooling refer to the formulas given in Chapters 12, Heating Load, and 13, Cooling Load. The amount of outdoor air introduced into the room must be checked against the ventilation requirements of state or local codes.) 2. Select number of outlets for each room, considering air quantity required and distance available for throw or as radius of diffusion. The same factors, as well as distance from floor level available as mounting height, structural characteristics of the space, and consideration of appearance, will determine the type of outlet used. 3. Arrange location of outlets in the room. Generally, the outlets must be evenly spaced to distribute the air uniformly throughout the room. More air, however, must be supplied and directed towards areas with exceptional heat gain or loss. An important point to consider is the combination of proper out let location and efficient duct design (see Chapter 21). Consult manufacturers' tables for recommended location and spacing of outlets. . Refer to Chapter 19 for a discussion of zone control. 4. Select size of outlets according to air quantities handled, permissible throat or discharge velocities, or effective throw, taking into consideration other factors, such as permissible noise level, etc. In order to determine whether the selection made will satisfy the requirements of the job, the type, size, and loca tion of the outlet must be checked against manufacturers' rat ings. The most important questions to be considered are: a. Will drafts be created because of divergence between rated throw (radius of diffusion) and distance between outlet and nearest obstacle (wall, beam, column, etc.) in the air stream. b. Will drafts be created because of excessive cooling tempera ture differential or too low mounting height of the outlet? c. Will drafts created because of too low velocity energy of the air stream cause excessive downward air flow in cooling installations? d. Will the air pass through the outlet at too high a velocity and thereby cause an excesive increase in noise level? Balancing the System In designing a system, the engineer aims to size ducts and outlets in such a manner that the supply of air is properly distributed. He may, however, feel it necessary to oversize certain trunks, branches, or outlets to allow flexibility or to permit future redistribution, so that the system as designed may not be self-balancing. Even if ducts are designed for self-balancing and outlets are properly selected, all air sys tems must be balanced, that is, the amount of air through supply ducts, supply outlets, outdoor air intakes, exhausts, return outlets, and ducts must be properly adjusted so that the air quantities correspond closely with the design quan tities. Balancing, therefore, is part of the field test procedure to which each air-conditioning system should be subjected in order to determine whether the capacity and performance of the equipment correspond with the design. For balancing, air systems may be equipped with dampers in supply, return, and outdoor air ducts, splitter dampers, or dampers in outlets. In selecting the desired type of damper or balancing method, the following points should be kept in mind: 1. Unfavorable effect on air stream and noise level should be avoided. This trill often rule out blank-offs or dampers in out lets, unless such dampers are of special design. 2. It should be possible to alter outlet volume without alter ing the direction of discharged air, and to measure the amount of air handle! without difficulty. Blanking off part of the area of supply outlets makes this difficult. Generally speaking, it is most satisfactory to install dampers at some distance back of outlets so as to avoid disturbing the air flow. Dampers in both supply and return ducts form the most flexible means of controlling supply of air to the room and static pressure within the room. (Refer . to following section Directional and Volume Control for dis cussion of various air distribution control devices.) - Instruments for balancing include instruments for meas uring air quantities, static pressure, temperature and hu midity. Commonly used instruments are the rotating vane anemometer, deflecting vane anemometer, thermal ane mometer, smoke gun, clamp type ammeter-voltmeter, ding psychrometer and thermometers. Pressure, humidity and temperature recorders are sometimes useful. The Pitot tube and a manometer may be used on higher velocities, but only with the technique prescribed for its use by the manu facturer for the tube used. (See Air Flow Measurement in Chapter 44.) The following balancing procedure is recommended for air systems: ' - 1. Open all duct and outlet dampers. 2. Measure fan capacity. This can most often be done with a rotating vane anemometer inside the fan inlet plenum. For ex haust fans the discharge outlet will often serve. ' 3. Measure fan motor input. 4. Determine approximate flow at each outlet- 5. Adjust outlets or branches so that outlet deviation (from design quantity) is approximately'the same (percentagewise) as fan capacity deviation (from total design quantity). 6. Recheck fan capacity. - 7. Adjust fan speed or main trunk damper to make fan capac ity equal to design. (The fan laws apply when changing speeds; quantity varies directly with speed,--power input as the cube of speed.) Use power input readings to check poadbility of over loading the motor. ' The procedure outlined may be shortened depending on the type of installation. For instance, where many outlets serve one room, exact balancing of each outlet may not be required, so long as drafts, noise and temperature differences are checked. Experience and judgment are valuable in de termining how carefully or thoroughly a system must be tested and adjusted. DIRECTIONAL AND VOLUME CONTROL Duct Approaches to Outlets The importance of the manner in which the air stream is introduced into the outlet cannot be overestimated. To ob tain correct air distribution, the velocity of the air stream must be as uniform as possible over the entire connection to "1 278 CHAPTER 20 1959 Guide the duct, and perpendicular to the outlet face. No air outlet can compensate for improper duct approach. A wall grille installed at the end of a horizontal duct and a ceiling outlet at the end of a vertical duct receive the air perpendicularly and at (for practical purposes) uniform velocity over the entire duct cros3-section, provided the system is carefully designed. However, very few outlets are installed in this manner. Most side wall outlets are installed either at the end of vertical ducts or in the side of horizontal ducts, and most ceiling outlets are attached either directly to the bottom of horizontal ducts or to special vertical take off ducts which connect the outlet with the horizontal duct. In all these cases, special devices for directing and equalizing the air flow are necessary to obtain proper direction and distribution of the air. ' - The influence of the duct approach on outlet performance has been investigated for vertical stack heads with plain c Stodr 14 to. x 6 m. Outlet* 14 in. * 9 in. Stocfc Velocity $00 fpm A. Rounded Throat and Rounded Bade B. Roondod Throat and Bode and 2 SpEtten. C. Square Throat and Bock and 6 Guide Vane*. fig. 10.... Outlet Velocity and Air Direction Diagrams for Stack Heads with Expanding Outlets openings" or equipped with grilles" and for side outlets on horizontal ducts." In the tests conducted with the staek heads it was found that it is necessary- to provide splitters or guide vanes in the elbows at the top of the vertical stacks regardless of the shape of the elbows, whether of rounded, square or expanding types. Cushion chambers at the top of the stack heads have no beneficial effect. Fig. 10 shows the direction of flow, distribution-and velocity (measured 12 in. from opening) of the air for various types of stack heads tested, expanding from a 14 x 6 in. stack to a 14 x 9 in. opening, without grille. The air velocity for each was 500 fpm in the stack below the elbow, but the. direction of flow and the distribution pattern are generally indicative of per formance obtainable with nonexpanding elbows of similar shapes for a range of velocities 200 to 1400 fpm." In tests conducted with 3 x 10 in., 4x9 in., and 6x0 in. side outlets in a 6 x 20 in. horizontal duct at duct velocities of 200 to 1400 fpm (in the 6 x 20 in. section) it was found that multiple curved deflectors produced the best flow characteristics. Vertical guide strips in the outlet were not so effective as curved deflectore. A single scoop type deflector at the outlet did not improve the flow pattern obtained from a plain outlet, and was therefore not found to be desirable. Directional Control ' Many devices for directing and equalizing air flow in side wall and ceiling outlets are now commercially available, and should be used whenever necessary. They are indispensable for all side outlets in horizontal ducts and for most ceiling outlets. Ceiling outlets are usually installed below horizontal sup ply ducts so that the supply air has to make a 90-deg turn before entering the outlet itself. The shorter the connection between bottom of duct and outlet, the greater is the need for directive devices to obtain uniformity of flow. Generally speaking, conditions and remedy in such cases strongly re semble those for side outlets in horizontal air ducts. Ceiling ducts often have a rectangular cross-section, while the con nections to the ceiling outlets are circular. It will then be quite difficult to install turning vanes successfully, particu larly if the ducts .are shallow and the connection areas are comparatively large. This will be the case when more than one outlet is installed on one duct run, and restrictions of duct areas must be avoided. In such cases good results have been obtained by using a series of vertical guide strips, in stalled at right angles to the direction of air approach in the outlet connection where it leaves the horizontal air duct. Volume Control Various methods are used to regulate volume of supply and return (exhaust) air. Some of these accomplish only minor changes in volume; most of them, however, permit a range of adjustment from maximum air supply to complete shut-off. When selecting type and location of such dampers, the following points must be considered, especially when the volume control feature is to be located near the air outlet itself: (1) deflection of air stream by the damper; (2) need and feasibility of directional control; (3). increase of noise level due to irregular and localized high air velocities caused by damper operation. The following types of volume control are most frequently encountered: 1. Slide Damper. A single plate which can be pushed across the duct. Since its operation changes the free area of air passage in a one-sided manner, it should not be located near any air outlet, and its use is practicable only where no intermediate setting between full open and closed is required. 2. Hit-and-Miss Damper. Two slotted plates or discs, closely adjacent; by moving one of the two plates the re spective slots may be opened or closed. This.type of volume control may be installed close to an air outlet and it is easy to operate, but its main disadvantage is that even in the open position the air passage area is blocked by at least 50 percent. This requires oversizing of the air outlet in order to avoid excessive increase of noise level. 3. Splitter Damper. A single blade sheet metal plate hinged at one edge, usually located at the branch connection of a duct or outlet. It is easy to operate, but often causes irregular air flow in the duct. When used in connection with, and near an outlet, additional directional control is required. 4. Butterfly Damper. A single blade sheet metal plate hinged in the middle, usually located in a straight duct run. . ij $ 1: 4s! Air Distribution. .. 279 Table 2____ Recommended Return Intake Face Velocities tntdee Location Velocity Over Grot* Area Fpm Above occupied zone.................................... Within occupied zone, not near seats... Within occupied zone, near seats............. Door or-wall louvers..................................... Undercutting of doors (through under cut area)....................................................... 800 up 600-800 400-600 200-300 200-300 Table 3.... Approximate Pressure Drops for Lattice Return Intakes tocher Water Gaga--Standard Air Percent Free Ana foe* Velocity, Fpa ` 400 500 600 700 800 900 1000 50 0.06 0.09 0.13 0.17 0.22 0.28 0.35 60 0.04 0.06 0.09 0.12 0.16 0.20 0.24 70 0.03 0.05 0.07 0.09 0.12 0.15 0.18 80 0.02 003 0.05 0.07 0.09 0.11 0.14 It is easier to handle than a splitter damper, since only half the motion is necessary to change its setting. However, if located too close to an air outlet, it is objectionable because its operation frequently results in a condition whereby two high velocity jets are created along the sides of the duct, or the air spills immediately downward into the occupied zone. 5. Louver Dampers. Numerous designs have been devel oped-incorporating a series of splitter or butterfly dampers across the duct or air outlet. Their main advantage consists in retaining greater uniformity of air flow, and in requiring less depth for installation. Some designs provide for louver blades moving in opposite directions, and while decreasing free air passage area, retain a constant air flow direction along the axis of the duct air outlet connection. ' RETURN AND EXHAUST INTAKES The selection of return and exhaust intakes depends on: -(1) velocity in occupied zone near intake; (2) permissible pressure drop through intake; and (3) noise: 1. Velocity. The control of the room air motion for the maintenance of comfort conditions depends on the proper selection of the supply outlets. The effect of air flow through return intakes upon air movement in the room is slight. Air handled by the intake approaches the opening from all direc tions and its velocity decreases rapidly as the distance from the opening increases. Therefore, drafty conditions will rarely be encountered near return intakes. Recommended return intake face velocities are given in Table 2. 2. Permissible Pressure Drop. The permissible pressure drop will depend on the choice of the designer. Table 3 gives pressure drop through plain,lattice intakes as a function of free area and face velocity. Proper pressure drop allowance should be made for con trol or directive devices. 3. Noise. The problem of noise generated by return in takes is the same as that for supply outlets. In computing resultant room noise levels from the operation of an air-con ditioning system, the return intake must be included as a part of the total grille area. The major difference between the supply outlets and return intakes is the frequent installa tion of the latter at ear level. When so located, it is recom mended that the return intake velocity be not in excess of 75 percent of the m*Timntr) permissible outlet velocity. The location of return and exhaust intakes does not criti cally affect air motion, unless room air velocities in the occu pied zone near the intake exceed comfort limits. The loca tions of return or- exhaust intakes are, however, important for obtaining the desired room temperature equalization. Ceiling locations for exhaust outlets are recommended for bars, kitchens, lavatories, dining rooms, dub rooms, etc. where warm air will rise to the ceiling level. In heating installations, location of the return grilles in the filing or high on the wall is not .recommended, as it may result in stratification of the conditioned air, and--depending on the relative location of supply and . return outlets--in short- circuiting: (Refer to previous section Outlet Location and Selection.) Some ceiling outlets combine the supply and return open ings in a single unit. This method is used for heating as well as for cooling applications. However, the application for heating is more critical and requires consideration of ceiling height, amount of outside wall area, and number of air changes required. In some cases, stratification of warm air may cause short-circuiting. (Refer to previous section Out let Location and Selection.) Floor locations of returns are used in heating installations for ceiling or side-wall supply. When located so that air is drawn across exposed walls, the performance of the system may be somewhat improved. In general, floor locations tend to collect dirt and refuse. ' Wall and door locations of exhaust outlets depending on their elevation, have the characteristics of either floor or ceiling returns. In large buildings with many small rooms, the return, air may be brought through door grilles or door undercuts into the corridors, and then to a common return or exhaust. The pressure drop through door returns should not be excessive; otherwise the air distribution to the room may be seriously unbalanced with toe opening or rinsing of the doors. Outward leakage through doors or windows cannot be counted upon for dependable results. SPECIFIC APPLICATIONS For theaters and auditoriums the air distribution methods used are the downward distribution system with ceiling dif fusers, and the horizontal distribution system with ejector nozzles or wall diffusers. Fig. 11 shows both methods. Ceiling distribution is accomplished by ceiling outlets under main ceiling and balcony. It is indicated when main ceiling or Rear s0 distribution Ceding distribution fig. II.... Air Distribution Methods for Theaters, Churches, and Auditoriums . . fi 280 CHAPTER 20 1959 Guide H= , Ui________ mm_____ I-- 11 1 1i O O O' A 5 5' -o* Winter convection current A. far mlni|. TTn--tiefnntney for twtinf in irvmriimat-- the ootaida temperatore ia ewaatentty below 40 F, and single glus and own* slated walla ere prevalent. B. Performance approximately that of A when email diffusers are need in bottom of the duet. . C. Satisfactory for cooling. Satisfactory for heating if direct radiation b prop-, arty controlled. D. flstirii^tiuy for KntK wwlm| siwt bfiatmc- air should be discharged tightly away (ran tha walland (or low valodtba, ahonld be *""< oat parallel to the walL Rg. 12.... Distribution Methods for Small Rooms A. Star WatL High outlet velocity, satisfactory it properly deeigaod; poarf- bQity of excessive air motion and drafts if used for wroog application. B. Front tPeO. High outlet velocity, molts same sa A . C- Front oad Star WeB*. Moderate room air motion, outlet blowa should not impinge firing rbe to downdrafts in center. D. Center. Moderate sir motion, do impingement of air strains. Good insults. E. Ons Side. Moderate roam sir motion; should blow toward exposed wall. Good results. F. Ceding. Low room air motion. Good results. Outlets should be selected of sufficient me to allow (or Mooting wben not located in perfect squares. . Rg. 13.... Small Store Cooling Distribution i|-' 4y % H- H balcony is cut up by architectural treatment or beams. The only critical points are under the balcony, and (occasionally) above the very rear of the balcony, where ceiling heights are low and where direct impingement of air is sometimes a hazard. Wall or ejector distribution is particularly applicable for relatively long and narrow theaters. It is essential with this type of distribution that there be no interference with the movement of air throughout its entire path from the high velocity nozzles to the front of the theater. The ceiling should be smooth, without projecting beams or obstructing orna mentation. For large theaters, relatively high velocities can be used. These will work satisfactorily if adjustable outlets are used to avoid areas of local turbulence. In small or medium size theaters, it is sometimes practi cable to use side-wall or front-wall distribution. For the satisfactory operation of such a system during the winter heating period, the returns should preferably be located at the floor level and near the front of the theater to prevent cold spots resulting from exposed wall convection or infiltra tion from exits. For multi-room buildings diagrams shown in fig. 12 illus trate distribution methods for small rooms with exposed wall, suehas offices, hotel (guest) rooms, hospital (patients) rooms, apartments, etc. For a small store the cooling performance of various dis tribution methods is illustrated in fig. 13. REFERENCES 1G. L. Tuve: ASHVE Research Repost No. 1476--Air veloci ties in ventilating jets (ASHVE Transactions, Vol. 59, 1953, p. 261). . Alfred Koestel: ASHVE Research Report No. 1512--Com puting temperatures and velocities in vertical jets of hot or cold air (ASHVE Transactions, VoL 60, 1954, p. 385). Alfred Koestel: ASHAE Research Report No. 1534--Paths of horizontally projected heated and chilled air jets (ASHAE Transactions, Vol. 61, 1955, p. 213). - *H. B. Nottage, J. G. Slaby, and W. P. Gojsza: ASHVE Re search Report No. 1458--Outlet turbulence intensity as a factor in isothermal-jet flow (ASHVE Transactions, Vol. 58, 1952, p. 343). *G. E. McElroy: Air Flow at Discharge of Fan-Pipe Lines m Mines (U. S. Bureau of Mines Report of Investigations R. J. 3730, November 1943, p. 19). ,; Alfred Koestel, Philip Hermann, and G. L. Tuve: ASHVE Research Report No. 1404--Comparative study of ventilating jets from various types of outlets (ASHVE Transactions, Vol. 56. 1950, p. 459). * R. D. Madison and W. R. Elliot: Throw of air from riots and jets (ASHVE Journal Section, Heating, Piping and Air Condi tioning, November 1946, p. 108). Alfred Koestel and G. L. Tuve: ASHVE Research Report No. 1328--Hie discharge of air from a long riot (ASHVE Transactions, Vol. 54,1948, p. 87). Alfred Koestel and C. Y. Young: ASHVE Research Report No. 1429--The control of air streams from a long riot (ASHVE Transactions, Vol. 57, 1951, p. 407). fi !i $ Air Distribution 281 ** Alfred Koestel, Philip Hermann, and G. L. Tuve: ASHVE RgggAMTH Report No. 1366--Air streams from perforated panels (ASHVE Transactions. Vol. 55, 1949, p. 283). ' aH. B. Nottage, J. G. Slaby, and W. P. Gojsza: ASHVE Research Report No. 1443--Isothermal ventilation--jet funda mentals (ASHVE Transactions, Vol. 58, 1952, p. 107). " Entrainment in Ventilating Jets (Case Institute of Tech nology, unpublished paper). "D. W. Nelson, D. H. Krans, and A. F. Tuthill: ASHVE Research Report No. 1155--The performance of stack heads (ASHVE Transactions, VoL 46, 1940, p. 205). "D. W. Nelson, D. H. Lamb, and G. E. Smedberg: ASHVE Research Report No. 1206--Performance of stack heads equipped with grilles (ASHVE Transactions, Vol. 48, 1942, p. 279). **D. W. Nelson and G. E. Smedberg: ASHVE Research Report No. 1226--Performance of side outlets on horizontal ducts (ASHVE Transactions, Vol. 49,1943, p. 58). BIBLIOGRAPHY Note: This guide to the literature on air distribution is pur posely restricted to papers resulting from research sponsored by The American Socibtt op Heatino and Aib-Conditioniko Engi neers and other easily accessible material. ASHAE Research Laboratory Cyril Tasker: ASHVE research in air distribution and air duct friction (ASHVE Journal Section, Heating, Piping and Air Conditioning, April 1948, p. 125). H. B.-Nottage: ASHVE Research Report--Ventilation jets in air distribution (See Reference 1). The following papers based on this report have been published: EL B. Nottage: ASHVE Research Report No. 1360--Turbu lence--a fundamental frontier in air distribution (ASHVE Transactions, Vol. 55, 1949, p. 193). H. B. Nottage: ASHVE Research Report No. 1402--A simple heated-thermocouple anemometer (ASHVE -Transactions, Vol. 56, 1950, p. 431). H. B. Nottage, J. G. Slaby, and W. P. Gojsza: ASHVE Re search Report No. 1443--Isothermal ventilation-jet funda mentals (ASHVE Transactions, Vol. 58, 1952, p. 107). H. B. Nottage, J. C. Slaby, and W. P. Gojsza: ASHVE Re search Report No. 1441--A V-wire direction probe (ASHVE Transaction, Vol. 58, 1952, p. 79). H. B. Nottage, J. G. Slaby, and W. P. Gojsza: ASHVE Re search Report No. 1458--Outlet turbulence intensity as a fac tor in isothermal-jet flow (ASHVE Transactions, VoL 58, 1952, p. 343). '' H. B. Nottage, J. G. Slaby, and W. P. Gojsza: ASHVE Re search Report No. 1461--A smoke-filament technique for ex perimental research in room air distribution (ASHVE Trans actions, Vol. 58, 1952, p. 399). H. B. Nottage, J. G. Slaby', and W. P. Gojsza: ASHVE Re search Report No. 1459--Exploration of a chilled jet (ASHVE Transactions, Vol. 58, 1952, p. 357). _ H- B. Nottage: Ventilation Jets in Room Air Distribution. Originally submitted as a PhJX thesis to Case Institute of Tech nology (3 volumes). Loan copies available from ASHAE Re search Laboratory. Volume I: Data and Interpretations of Tests for Ventila tion Jets Discharging Horizontally into a Large Confining Space (131 pages + 67 figs. + 9 tables). Volume II: Appendix A. Survey of the Literature on the of Ventilation Jets and the Related Fundamentals of Turbulent Flow (499 pages inch figs, and tables). Volume 1H: Appendixes B to H. General Features of the Experimental Installations, Instrumentation, and Operations, Boundary-layer Theory'and Work-energy Treatment (142 pages md. figs.). ASHAE Cooperative Research at Case Institute of Tech nology TMo. 1140--The use of air velocity meten . (ASHVE Transactions, VoL 45, 1939, p. 645). G. L. Tuve and D. K. Wright, Jr.: ASHVE Research Report No. 1162--Air flow measurements at intake end discharge open ings and grilles (ASHVE Transactions, Vol. 46. 1940, n. 313). G. L. Tuve, G. B. Pricster, and D. K. Wright, Jr.: ASHVE Reseabch Report No. 1204--Entrainment ana jet-pump action of air streams (ASHVE Transactions, Vol. 48, 1942, p. 241). G. L. Tuve and G. B. Priester: ASHVE Rrsbabcm Report No. 1248--Control of air streams in large spaces (ASHVE Transactions, Vol. 50, 1944, p. 153). Alfred Koestel and G. L. Tuve: ASHVE Rewmbcw Report No. 1328--The discharge of air from a long riot (ASHVE Transactions, VoL 54, 1948, p. 87). Alfred Koestel, Philip Hermann, and G. L. Tuve: ASHVE Research Report No. 1366--Air streams from perforated panels (ASHVE Transactions, Vol. 55, 1949, p. 283). Alfred Koestel, Philip Hermann, ar>d G. L. Tuve: ASHVE Research Report No. 1404--Comparative study of ventilating jets from various types of outlets (ASHVE Transactions, VoL 56, 1950, p. 459). Alfred Koestel and C. Y. Young: ASHVE Rustnnnw Report No. 1429--The control of air streams from a long riot (ASHVE Transactions, Vol. 57, 1951, p. 407). G. L. Tuve: ASHVE Research Report No. 1476--Air veloci ties in ventilating jets (ASHVE Transactions, VoL 59,1953, p. 281). ' Alfred Koestel and G. L. Tuve: ASHAE Research Report No. 1553--Performance and evaluation of room air distribution systems (ASHAE Transactions, Vol. 61, 1955, p. 533). ' Alfred Koestel and J. B. Austin, Jr.: ASHAE Research Re port No. 1580--Air velocities in two parallel ventilating jets * (ASHAE Transactions, Vol. 62, 1956, p. 425). Alfred Koestel: ASHAE Research Report No. 1618--Jet velocities from radial flow outlets (ASHAE Transactions, Vol 63, 1957, p. 505). ASHVE Cooperative Researdi at Kansas State College Linn Hel&nder and C. V. Jakowats: ASHVE Research Re-' port No. 1327--Downward projection of heated air (ASHVE Transactions, Vol. 54, 1948, p. 71). Linn Helander, S. M. Yen, and R. E. Crank: ASHVE Re search Report No. 1475 (In cooperation with the Industrial Unit Heater Association)--Maximum downward travel of heated jets from standard long radius ASME uozzles (ASHVE Transactions, Vol. 59, 1953, p. 241). Linn Helander, S. M. Yen, and L. B. Knee: ASHVE Re search Report No. 1511--Characteristics of downward jets of heated air from a vertical delivery discharge unit heater. (ASHVE Transactions, Vol. 60,1954, p. 359). S. M. Yen, Linn Helander, and L. B. Knee: ASHAE Research Report No. 1562--Characteristics 6f downward jets from a verti cal discharge unit heater (ASHAE Transactions, VoL 62, 1956. p- 123)- Linn Helander, 8. M. Yen, and Wilson Tripp: ASHAE Re search Report No. 1601--Outlet characteristics that affect the downthrow of heated air jets (ASHAE Transactions, Vol 63. 1957, p. 255). Rudiger Knaak: ASHAE Research Report No. 1619--Veloci ties ana temperatures on axis of downward heated jet from 4-inch long-radius ASME nozzle (ASHAE Transactions, Vol. 63, 1957, p. 527). ASHVE Cooperative Research--General E. L. Davies: ASHVE Research Reports No. 857, 911, and 966--Measurement of the flow of air through registers nnH grilles (ASHVE Transactions, Vol. 36, 1930, p. 201: Vol 37 1931, p. 619; and Vol. 39, 1933, p. 373). D. W. Nelson and D. J. Stewart: ASHVE Research Report No. 1076--Air distribution from side wall outlets (ASHVE Transactions, Vol. 44,1938, p. 77). A. M. Greene, Jr. and M. H. Dean: ASHVE Research Re port No. 1092--The flow of air through exhaust grilles (ASHVE Transactions, Vol. 44, 1938, p. 387). D..W. Nelson, D. H. Krans. and A. F. Tuthill: ASHVE Re search Repost No. 1155--'The performance of stack beads (ASHVE Transactions, Vol. 46, 1940, p. 205). 282 CHAPTER 20 1959 Guide A. P. Kratc, A. E. Herehey, and E. B. Engdahl: ASHVE Re search Repoet No. 1165--Development of instruments for the study of air distribution in rooms (ASHVE Transactions, Vol. 46, 1940, p. 351). D. W. Nelson, D. H. Lamb, and G. E. Smedberg: ASHVE Research Repost No. 1206--Performance of stack heads equipped with grilles (ASHVE Transactions, Vol. 48, 1942, p. 279). D. W. Nelson and G. E. Smedberg: ASHVE Research Re post No. 1226--Performance of side outlets.on horizontal ducts (ASHVE Transactions, VoL 49,1943, p. 58). Other Papers Presented at ASHVE Meetings D. J. Stewart and G. F. Drake: ASHVE Research Report No. 1051--The noise' characteristics of air supply outlets (ASHVE Transactions, Vol. 43, 1937, p. 81). R..A. Nielsen: ASHVE Reseabch Report No. 1158--Dirt patterns on walls (ASHVE Transactions, Vol. 46,1940, p. 247). G. S. Dauphinee and Peter Argentieri: ASHVE Research Repost No. 1361--Balancing air delivery of a system of manifold air diffusers (ASHVE Transactions,.Vol.'55, 1949, p. 213). . John Rydberg and Per Norback: ASHVE Research Report No. 1362--Air distribution and draft (ASHVE Transactions, VoL 65, 1949, p. 225). S. F. Gilman, H. E. Straub,. A. E. Hershey, and R. B. Engdahl: ASHVE Research Report No. 1471--Room air dis tribution research for year 'round air conditioning, Part I--Sup ply outlets at one high sidewall location (ASHVE Transac tions, Vol. 59, 1953, p. 151). * H. E. Straub and S.'F. Gilman:. ASHVE Research Repost No. 1504--Room air distribution research for year 'round air conditioning. Part IX--Supply outlets at three floor locations (ASHVE Transactions, VoL 60, 1954, p. 249). H. G. Elrod, Jr.: ASHVE Research Repost No. 1514--Com putation charts and theory for rectangular and circular jets (ASHVE Transactions, Vol. 60, 1954, p. 431). Miscellaneous Articles G. L. Tuve: Measuring air distribution and grille perform ance in air. conditioning (ASHVE Journal Section, Healing, Piping and Air Conditioning, November 1937, p. 700). . F. F. Stevenson: Air discharge from narrow riots {Heating, Piping and Atr Conditioning, May 1941, p. 308, and June 1941, p. 368. Discussed by J. R. Fellows and D. W. Nelson, loc. cit-, September 1911, p. 558 and 559). Sturm: Vertical air distribution in tall buildings (Heating, Piping and Atr Conditioning, June 1947, p. 69 and September 1947, p. 93). , . . Efficient air distribution in theatre (Heating, Piping and Air Conditioning, August 1947, p. 107; September 1947, p. 113; No vember 1947, p. 103). L. T. Avery and J. Black: Test every air conditioning sys tem (Heating and Ventilating, June. 1948, p. 96). . L. R. Phillips: Balancing an air conditioning system (fie- frigerating Engineering, July 1950, p. 111). - .. What is a draft? {Heating, Piping and Atr Conditioning, May 1951, p. 67; July 1951, p. 71; September 1951, p. 69; January 1952, p. 113; March 1952, p. 73). Seven questions on ducts and grilles (Heating, Piping and Atr Conditioning, May 1952, p. 106 and July 1952, p. 111). ' ' R. V. Martclli and H. 0. Scarlett: Air distribution studies (Heating, Piping and Atr Conditioning, November 1952, p. 77. Discussed by W. O. Huebner, loc. dt., January 1953, p. 119 and by the authors, March 1953, p. 85). I CHAPTER 21 AIR DUCT DESIGN Pressure Changes, Friction tosses, Circular Equivalents of Rectangular. Ducts, Dynamic losses, Pressure Losses in Elbows, Pressure tosses in Divided-Flow Fittings, Losses Due to Area Changes, Duct Design Methods and Examples, HighVelocity Duct Design, Duct Construction Details, Heat Losses from Ducts IN THE design of air duct systems, the objective is to provide a system that, within prescribed limits of noise molecules along the sides of the duct. Pressure losses in. straight pipes are termed friction losses and are character and space available for ducts, efficiently transmits the re ized by dependence upon Reynolds number. (See Chapter 4.) quired flow rate of air (cfm) to each space while maintaining Section BC is a converging section. The duct area is re a proper balance between investment and operating - cost. duced,' and consequently the flow is accelerated. This is a When the heating, cooling, or ventilation load is established, _ stable and efficient process and the loss in total pressure is the total flow rate of air required can be determined by seen to be small. The marked decrease in static pressure is methods shown in Chapters 12 and 13. The problem is then caused by conversion of static to velocity pressure in ac to distribute the supply air properly among the spaces. cordance with Equation 2. . ' PRESSURE CHANGES Section CD presents the friction loss in the section of smaller duct. Since friction losses increase with nearly the Ductwork imposes resistance to air flow which must be square of the velocity, the pressure line falls much more overcome by the expenditure of mechanical energy; this rapidly than in Section AB. energy is ordinarily supplied by a fan. The portion of the air ' An abrupt expansion occurs at DE. The duct area is flow rate from the fan that is transmitted, to a particular abruptly increased and the flow decelerated. The process is space is governed by the law that the loss in total pressure an inefficient one and the loss in total pressure is therefore from the fan outlet must be the same along each air path. large. The velocity pressure is decreased at E in accordance This also holds for the return-air system except that the with Equations 2 and 3, and the static pressure rises. This loss in total pressure refers to the fan inlet. In air-condition mid the pressure loss at BC are termed dynamic losses, and ing and ventilating work the pressure differences are ordi are characterized by being essentially independent of Reyn narily so small that the equations for incompressible flow olds number. Dynamic losses occur because of changes in can be applied. Additional simplicity is obtained by con the direction or velocity of the air, and hence occur at duct sidering the air to be at the standard density of 0.075 lb transitions, bends (elbows), and obstructions such as damp per cu ft. ers. As will be shown later, dynamic losses can be specified At any cross-section in a duct the total pressure H is the in terms of a constant times the velocity pressure at a cross sum of the static pressure P and the velocity pressure H9. section under consideration. Thus, - Beginning at Section E the velocity pressure is constant, H = -P + H, and the static and total pressures again decrease uniformly (1) due to wall friction. The static pressure at F is zero, as Pressures are considered in units of inches of water. The referred to the atmosphere. The total presure is the velocity velocity pressure is then given by pressure and is a measure of the kinetic energy of the stream as it discharges from the duct. where V is defined by the equation V - Q/A (3) where: V -- mean velocity of flow, feet per minute. Q " air-flow rate, cubic feet per minute. A ~ cross-sectional area of duct, square feet. The total pressure H is a measure of the total mechanical energy at a cross-section. In any duct system, the total pressure always decreases in the direction of the air flow. Static and velocity pressure are mutually convertible and either can increase or decrease in the direction of flow. Typical pressure changes in a duct system are illustrated in Fig. 1. Between Sections A and B, the static and total pressures decrease uniformly because of friction between air 284 CHAPTER 21 1959 Guide Air Duct Design 285 CU FT OF AIR PER MINUTE (B--*f on Standard Air of 0.075 & per cu ft dmdtj flowing Ibroogh overage, dnoo, mod, gofvaatzod ratal doctz barng approximate!, 40 /oioil per. 100 Cai^M Do oof exfrapolati bafov chart. fig. 2.... Friction of Air in Stroight Ducts for Volumes of 10 to 2000 Cfm (Band on Standard Air of 0.075 lb per co ft donrify flowing through avwrope, dean, round, gefvamxod aotaf ducts haring approximately -40 Joint* por 100 ft-) fig. 3.O.. Friction of Air in Straight Ducts for Volumes of 1000 to 100,000 Cfm The distinction between static and total pressure is im portant, because'the former is conventionally used as the basis for system design, but the latter determines the actual mechanical energy that must be supplied to the system. Note in Fig. 1 that the static pressure decreases and then increases in the direction of flow. Moreover, it even becomes negative (below atmospheric). Therefore, in dealing with static pres sures, distinction must always be made between static pres sure loss (Section AB) and static pressure change as a result of conversion of velocity pressure (Section BC). FRICTION LOSSES Pressure drop in. a straight duct is caused by surface friction, and this friction loss is most readily calculated by means of the Air Friction Charts, Figs. 2 and 3, covering volume ranges of 10 to 2000 cfm, and 1000 to 100,000 cfm, 286 CHAPTER 21 1959 Guide respectively. These charts were developed by the ASHAE Research laboratory.1 . . The charts, figs. 2 and 3,` were constructed from die basic flow equation for the pressure loss in circular ducts (see Chapter 4): '. (4) where H/ *=* head loss due to friction, inches of water. / " a nondimensionai friction coefficient, which for air conditioning work depends upon Reynolds number and the relative roughness of the conduit.-Approximate - values of f were taken from the work of Moody* where e ** 0.0005 ft. (See Chapter 4, Fig. 4, Relation Between ductwork.4 The correct friction loss for ducts of other than Friction Factor and Reynolds number.) It is numeri standard sheet-metal construction may be determined by cally equal to the reciprocal of the number of duct ' -multiplying the loses obtained from Figs. 2 and 3 by the diameters required to cause a pressure loss equivalent - factors found in Figs. 5 and 6. to one velocity pressure. " . . . Accurate experimental data on the absolute roughness for I = length of conduit; feet'. ' flexible tubing are not yet available. There is also little in- . D * inside diameter of conduit, feet. formation on the friction loss in ducts lined with acoustical H. = velocity pressure of mean velocity, inches of water.. material. Until definite information is available, it is recom- - The air friction chart is based on standard air with a den sity of 0.075 lb per cu ft, flowing through average, clean, round, galvanized metal ducts having approximately 40 joints per 100 ft. flg. 2 should not be used to obtain values . below the charts, by extrapolation, because critical flow would occur in this region and values so obtained would be unreliable. - Variations in air temperature of the order of 20 deg mended that the correction factor for very rough pipes be used for uncovered soft material, and the factor for medium roughness be used for material behind perforated metal. Example l illustrates the use of Fig. 3 to determine friction losS in a galvanized sheet-metal duct. Example* t, S, and 4 illustrate the use of Figs. 4, 5, and 6 in applying correction " factors for ducts of other than sheet-metal construction and for air at high temperature. . from 70 F affect duct friction very little. Figs. 2 and 3 wm therefore be used for aii air systems with temperatures from . 50 F to 90 F.` For systems carrying air at much higher tem peratures, however, the values found in the charts must be Example 1: Determine the friction loss when circulating 10,000 elm of air at standard density through 75 ft of .24-in. diameter galvanized duct. . Solution: Find 10,000 cfm on the left scale of Fig. 3 and corrected.' To determine the friction loss in such systems, the move horizontally right to the diagonal line marked 24 in. The actual flow rate or velocity existing at the nonstandard con other intersecting diagonal shows that the velocity in the pipe ditions must be used. -- Changes in humidity, or the usual changes in barometric pressure or in the pressures required to circulate the air is 3200 fpm; Directly below the intersection it is found that the . friction per 100 ft is 050 in.; then for 75 ft the friction will be 0.75 X 050 -- 038 in. In a like manner, any two variables may. through the systems, have little influence on duct friction and can be disregarded in calculating friction losses in ordi nary air-flow systems.1 For unusual conditions, the friction .values obtained from Figs. 2 and 3 must be corrected.' ' For ordinary applications, an excellent approximation for nonstandard temperatures is where A, -- AA, . (5) A, * friction loss under actual operating conditions, inches of water; . he -- friction loss obtained from Figs. 2 and 3 using the ac tual Sow rate or velocity existing under the nonstand ard conditions, inches of water. - K -- friction loss correction factor, obtained from Fig. 4, dimensionless. For ducts of other than standard sheet-metal construction, correction factors may be obtained from Figs. 5 and 6. The correction factors shown m Fig. 5 were computed for the value of , the roughness in feet, shown in Table 1.* Most ductwork today is fabricated from galvanized-iron or alumi num sheet metal, or flexible tubing. Fig. 6 presents in graphi cal form the recommended correction factors for aluminum To correct for pip* rovghnmu multiply friction fact ofetafcwd from fig*. 2 end 9 by correction factor obtained from Fig. 5. ' ' Fig. 5____ Correction Factors for Pipe Roughness : -\ f I > j (* 1 ] V '* ; \ i - 4 i f ` * ** - Air Duct Design 287' Table 1 .... Values of Roughness for Different? Rpes* .. Dogtvo Pipe ' of Ibugfcmtr be determined by the intersection of the lines representing the other two variables. Example t: If the duct in Example 1 is very rough, instead of galvanized, with 40 joints per 100 ft, find the total friction. Solution.* On Fig. 5 find (by interpolation between 12-in. and 40-in. pipe) the intersection of the 24-in. very Tough pipe line and the 3200 fpm velocity ordinate, and at the left margin read a correction factor of 2. The friction loss in the rough duct is therefore 2 X. 038 -- 0.76 in. Example 3.* If the duct in Example 1 is made of aluminum, of galvanized iron, find the total friction. Solution: On Fig. 6 find (by interpolation between 12-in. and 36-in. pipe) the intersection of the 24-in. line and the 3200-fpm velocity ordinate, and at the left margin read a correction factor of 031. The friction loss in the aluminum duct is therefore 031 X 038 = 035 in. Example 4: Determine the friction loss in the duct of Ex ample 1, if the temperature of the air transmitted through the duct.is 200 F. Solution: For t -- 200 F, the density of the'air is = 0.060 lb per cu ft. Hence, the actual air-flow rate in the duct is a 10.000 X 0.075 0.060 12,500 cfm and the actual velocity Qc 12,500 A m 3.14 4,000 fpm With Q -- 12500 and D = 24 in., find A. -- 0.77 in. of water per 100 ft in Fig. 3 and K -- 0335 in Fig. 4. The friction loss under actual operating conditions is: A. - 0335 X 0.77 = 054 in. per 100 ft. The friction loss for 75 ft is then 0.75 X 054 = 0.48 in. CIRCULAR EQUIVALENTS OF RECTANGULAR DUCTS . An air-handling system is usually sized first for round ducts. Then, if rectangular ducts are desired, their sizes are selected to provide flow rates equivalent to those of the round ducts, originally selected. ' A comprehensive study at the ASHAE Research Labora tory proved that for most practical'purposes rectangular ducts of aspect ratios not exceeding 8:1 will have the same friction pressure loss for equal lengths and mean velocities of flow as a circular duct of the same hydraulic diameter. When duct sizes are expressed in terms of hydraulic diameter, and when equations for friction loss in round and rectangular ducts are equated for equal flow rate and equal length, Equation 6 giving the circular equivalent of a rectangular duct is obtained.* Drawn Tubing......................... ..... New Steel or Wrought Iron Pipe.. Galvanized Iron.............................. Average Concrete........................... Average Riveted Steel................... Very smooth Medium smooth Average Medium rough Very rough 0.00000150.00015 0.00056.003. 0411 * Used in computing value* for FI*. S. . (aA)*-m d. 130 1.30 (o + '** (05)' (o + 6)* (6) where a = length of one side of rectangular duct, inches. b " length of adjacent side of rectangular duct, inches. . da " circular equivalent of a rectangular duct for equal friction and capacity, inches. Table 2 gives the circular equivalents of rectangular ducts for equal friction and flow rate for aspect ratios hot greater than 11.7:1 based on Equation 6* Note that the mean velocity in a rectangular duct will be less than in its circular equivalent. Multiplying or dividing the length of each side of a duct by a constant is the same- as multiplying or dividing the equivalent round size by the same constant. Thus, if the circollar equivalent of an 80 x 24 in. duct is required, it will be twice that of a 40 x 12 in. duct, or 2 x 23.0 = 46.0 in. DYNAMIC LOSSES Wherever eddying flow is present, brought about by sudden changes in the direction or magnitude of the velocity of the air flowing, a greater loss in pressure takes place than would occur in a steady flow through a similar length of straight duct having a uniform cross-section. The amount of this loss,, in excess of straight-duct friction, is termed dynamic-loss. Although dynamic losses may be assumed to be caused by changes in area actually occupied by the air flow, for con venience they are divided into two general classes: (1) those caused by changes in direction of the duct and (2) those caused by changes in cross-sectional area of the duct. Dynamic losses vary substantially as the square of the mwin velocity of the air, and are therefore conveniently ex pressed as a fraction of the velocity head: *`-c()' m . where Ed -- dynamic pressure loss, inches of water. V -- mean velocity of air flow, feet per minute. C = an experimentally determined constant (dynamic loss coefficient). Where different areas are involved, subscripts are used to denote the area to which the coefficient applies, as C\ for inlet area, Ct for outlet area, and C, for orifice area. The dynamic loss coefficient C is dimensionless and repre sents the number of velocity heads lost at the conduit transi tion or bend. Values of the dynamic loss coefficient for elbows j 288 CHAPTER 21 1959 Guide Table 2 ....Grcutar Equivalents of Rectangular Ducts for Equal Friction and Capacity OimeatioM In indw* Air Duct Design Table 2____ Circular Equivalents of Rectangular Ducts for Equal Friction and Capadty (Concluded) Diaenaons to Incbet 289 and other duct elements have been determined experimentally and are given in Tables 3 and 4. It should be noted, however, that absolutely reliable dynamic loss coefficients are not yet available for all- duct elements and that the information available for pressure losses due to area changes is generally restricted to symmetrical area changes. Jig. 7, which shows the relation of velocity pressure to velocity for standard air "(V = 400can be conven iently n<*d to find the total dynamic pressure loss for any duct element with known dynamic loss coefficient C. PRESSURE LOSSES IN ELBOWS . Dynamic-loss coefficients are nearly independent of the air-velocity and are affected by the roughnes of the duct walls only in the case of bends, for which the dynamic losses are often grouped with the friction losses to facilitate design calculations. An ASHAF survey" of available data has indi cated that the method of expressing the combined dynamic and friction losses due to an elbow as equivalent to the loss in a length L of similar straight duct is justified for design purposes, owing to the relation of the loss to the correspond ing friction factor f. Fig. 8 gives the additional equivalent length of duct in terms of widths W for elbows in rectangular ducts; Fig. 9 , gives the equivalent length of duct in terms of diameters D for round ducts. When these curves for additional equivalent length are used, the straight lengths of duct between elbows should be measured to the intersection of their center lines. Example 6: Use of Fig. 8 for the calculation of elbow losses. Given the portion of a duct system shown in Fig. 10, it is required to determine the pressure loss between points A and D. Air at standard conditions is being supplied at the rate of !K100 rfm in a 6 by 24 in.' galvanised duct of average construction. Elbows No. 1 and 2 have center line radii of 18 and 19 in, re spectively. Solution: For elbow No. 1 the radius ratio is Ri/Wi = 18/24 -- 0.75 and the aspect ratio is RJW\ = 6/24 = 025. The additional equivalent length for elbow No. 1 in terms of W is obtained from Fig. 8; {L/W)i = 11.5. Thus U = IL5 X 24/12 = 23 additional equivalent feet. Similarly for elbow No. 2, the ratio radius is ttt/W* = 9/6 -- 1-5 and the aspect ratio is Ht/Wt -- 24/6 = 4.0; Fig. 8 gives (.L/W)> = 6, so L* = 6 X 6/12 = 3 additional equivalent feet. ' The total length of the straight runs from A to D is l -- Ia-i + + lg.,, = 7 + 20 + 5 = 32ft and the additional equivalent length due to the elbows isL = Zn + Ia = 23 + 3 = 26 ft. Thus tile equivalent length of the system from AtoDisl + L -- 32 + 28 = 58 ft of 6 by 24 in. duct. The diameter of a circular duct, equivalent in friction and capacity to this rectangular duct, is 12.4 in. as given by the table of circular equivalents, Table 2. At a delivery rate of ^ f 290 CHAPTER 21 1959 Guide . ' 1 Fig. 7.... Relation Between Velocity and Velocity ' Head for Standard Air Fig. 8 .... Loss tn 90-Deg Elbows of Rectangular Cross-Section ' Table 3 .... Pressure Losses Due to Elbows (Ad^ioad Eqqirahaf Lout* m Excera of Friction to ifltonocfian of Center tines] . w-eec. o-Bce. BOUND illustrator CONDITIONS RECTANGULAR WTTM ON HITlt H1TM /o*o.$ 0.74 MESKNE L099 c* 1 Vo 1 V* S VALUE HON S092AR JCG ELKH* I.9Q* 0.*0 0.49 99* 29 1.9 2.0 ft/m 5BHlf' 0.9 0.29 0.79 1.0 1.9 UTTER 0.24 1.29* 0.90 0.97 0.19 RECTANGULAR sccnoN 0.9 9.79 1.0 UITt* 9.9 1.0 0-79 to 1.9 WJTEH 0.9 0.79 0.90 0.29 0.19 1.90 1.00 0.41 0.09 1.90 0.99 oo-occ. SQUARE JA.(TTtl (MCI worn . wmt runNine MUC& . unt* tcs WITH uues rOi Vm UITtR 0-9 0.9 0.4 0.7 0.0 1.0 1.0 1-9 NITER 0.9 09 0.9 0.2 0.4 0.79 0Jt 0.7 1.0 0.7 1.0 I.S 1.4 1.0 PLATT WO 9.19 0.12 0.44 0.10 0.99* FOMDWM9 0.10* * COHMCR EQUAL TO A 3JUa.AH ELNOR. OAK LOSS ON ENTERING VELOCITY. ` Values baaed on / values of approximately 0-02. b Values calculated from LfD and LfW valaesot Reference 5 fw/ -- 041 Note: Snperscxipt tmmbsa refer to referroceo at end of chapter. 2000 cfm, the A$HAF. Friction Chabt, Fig. 3, gives a loa of 0B in. of water per 100 ft. of 12.4-in. diameter duct. Thus the loss from A to D is 0B X 58/100 = 0348 in. of water. The use of elbows of radius ratio, R/W = IB, is considered good practice with respect to both installation and operation. In a given rectangular duct 6 by 24 in., for example, the elbow ldss will be greater for a flat bend where the aspect ratio, H/W -- 1/4, than if the bend of the same radius ratio had been made in the plane of the narrow dimension giving an aspect ratio, H/W = 4. Data now available for losses in compound bends/' * where two or more elbows are close together, do not warrant re finement of design calculations beyond use of the sum of the losses for the individual elbows. Actually, the losses are somewhat less than for two bends when they are placed to form a U bend, and somewhat more when they form a reversed, or S bend. Where angles of other than 90-deg bend are encountered, the loss may be considered as directly proportional to the I .{ A l t l | I Air Duct Design 291 Table 4 .... Pressure Losses Due to Area Changes TYPE EXPANSION iwnefHi TIOM TTONS coemceNT A|/A( c, C. 0.1 091 91 0.2 094 0.9 049 0.4 0.99 224 09 029 1.00 09 0.49 07 009 0.19 009 GRADUAL 09 OQI CONTRACTOR A/A, A ** oo 0.2 0.4 0.9 0.9 *t 0 1 ' 90* 49* C, 094*2 092 0-29 0.19 0.09 0.02* 0.04 C* CO* iL^ EXPANSION 20* 90* 40* 0.7* 022 029 049 ABRUPT At A Vi LOO EXIT lA^Ml) . SQUARE EDGE ORIFICE EXIT A, ^ OAR ACROSS -is DUCT PIPE ACROSS OUCT STREAM LINED A./A, 02 09 09 1.0 E/D 029 090 E/D 0.29 0.90 OIO 0.29 2.44 229 1.94 1.00 C. 14 4.0 C 020* 099 20 007* -0.29 0.90 CQUM. AREA TRANSFOR MATION PLANCED L_ ENTRANCE VA C ) < 14" 0.19* c 094" OUCT ENTRANCE FORMED ENTRANCE SQUARE ORIFICE ifENTRANCE SQUARE EDGE INDUCT -- A. fTT -- A./A, 0.0 02 0.4 0.9 09 1.0 A./A 0.0 0.2 0.4 0.0 0.9 C 099* C 0.09* C. 2-90 1.90 1.99 0.99 0.01 C. 2-SOu 1.99 1.21 0.94 0.20 Note 1: Subscript on C indicates crceo-ooction ot which velocity tg calculated (See. tar grampic, Equation 10 in text.) . Note t: Superscript number* refer to reference* at end eleb*pter. angle of bend. Losses* for elbows discharging air directly into a large space are higher than those given for elbows within duct systems. . Turning vanes may be advantageously employed in elbows, both to reduce the presure loss and to provide a more uni- form velocity distribution downstream from the bend.* " Vanes and concentric splitters are particularly recommended where miter elbows are used, because even the simplest vane forms will produce a substantial saving in pressure loss. . PRESSURE LOSSES IN DIVIDED-FLOW FITTINGS Analysis11 of available data for losses at branch take-offs indicates that the loss in the straight-through section is about 35 percent of that for abrupt enlargement (1) involving the same ratios of velocities and (2) that the loss in the divertedfiow section depends on the ratio of the velocity of diverted flow to total flow and on the angle the take-off makes with the main, and is at a minimum for'a natural relation that exists between these two variables. Some representative branch losses are given in Table 5. LOSSES DUE TO AREA CHANGES ' Area changes in ducts, generally unavoidable, are neces sitated frequently by the building construction or changes in the volume of air carried. Experimental investigations1*' " " " of pressure changes, and pressure losses at changes of the * area of duct cross-sectionB, indicate that the excess pressure loss over the normal friction loss is a dynamic loss due to a faster stream expanding into a slower stream, as determined by the actual areas occupied by the flow rather than the areas of the duct. No perceptible dynamic loss is due to the converging of the air stream itself where the flow is con tracted, but the air stream continues to converge beyond the edge of the contraction and reaches a minimum at the vena contracta. For contraction, therefore, the dynamic los is caused-by expansion from the vena contracta to the full area following the contraction. Abrupt contraction in area may therefore be considered as a special condition of abrupt enlargement. Fig. II illustrates (a) abrupt enlargement and (b) abrupt contraction. For a sudden symmetrical enlargement, a theoretical ex pression for the loss is . -(^1 Table 5.... Ratio of Pressure Loss to Branch Velocity Pressure Faiw^iff Anglt Ratio of Voiodty in ftrtmdi to Velocity m Mam Duct OA 0.8 0.8 1.0 1.5 2.0 3S> 90-deg 60-deg 45-deg 6.5 3.1 2.0 1.5 0.95 0.74 0.62 5.0 2.2 1.3 0.77 0.47 0.47 0.58 3.5 1.3 0.64 0.43 0.40 0.45 0.54 -0 ()'-'(=)' where H, " pressure loss due to sudden enlargement, based on standard air, inches of water. ' Vj o velocity of standard air in the inlet duct, feet per min ute. Fig. 11.... Air Flow at Abrupt Enlargement or Contraction of- Air Stream 292 CHAPTER 21 1959 Guide Vt " velocity of standard air in the outlet duct, feet per minute. 4. =* of the inlet duct, square feet. At area of the outlet duct, square feet. - Ci -- loss coefficient based on area A,. C> ~ loss coefficient based on area At. For a gradual symmetrical enlargement, Equation 8 changes to where H,, " pressure loss due to gradual enlargement, inches of water. Cr TM coefficient of loss, as ratio of loss to loss for abrupt expansion, dependent upon the total angle included between the sides of the duct. The loss for a sudden symmetrical contraction can be ex pressed as . but the included angle of convergence should not be greater than GO deg. 4. Where the greatest air carrying capacity per anuare foot of sheet metal is desired, rectangular ducts should he made as nearly square as possible. Aspect ratios (ratio of width to depth) greater than 8 to l should oe avoided. Where possible, a ratio of 4 to 1 or less should be maintained. 5. Ducts should be constructed of smooth material, such as steel or aluminum sheet metal. For ducts made from other materials, proper allowance for the change in roughness should be made* 6. Through the design procedures which follow, a reasonably ` precise estimate of the flow resistances offered by the system can be obtained. However, it should be recognized that in actual installations, resistances may vary considerably from the cal culated values because of variation in the smoothness of ma terials, types of joints used, and the ability of workmen to fabricate the system in accordance with the design. Fans and motors should therefore be selected to provide at least a slight factor of safety, and dampers should be installed in each branch outlet for balancing the system. Procedure for Duct Design The general procedure is as follows: where H, = pressure loss due to sudden contraction (Fig. 10b). C, -- loss coefficient based or orifice area A. .. V, " velocity of air through orifice, feet per minute. . The loss for a gradual symmetrical contraction can be similarly expressed as ' where the coefficient of loss C, depends on the included angle of the sides of the duct and the fiha-rpnpgg of the edges at the junction of taper to following duct section. . DUCT DESIGN The following discussion refers to ducts for commercial and industrial hearing, ventilating, and air-conditioning sys tems of the central station type. The design procedures given yield the statio pressure required to overcome the re sistance of the ductwork, including the supply outlets And return intakes. The fan selected for the duct system must not only produce this pressure but also the ftHHit.inna.1 pres sure required by the central equipment such as washers or spray chambers, heating or cooling coils, and filters. Pressure loses of these components should be obtained from the manufacturers' catalogs. Special duct design procedures for heating ducts used in residences can be found in Chapter 18 Warm Air Heating Systems. The design of ducts in industrial exhaust, systems is discussed in Chapter 52. General rules.which should be followed in the design of ducts are:I. 2 3 I. The air should be conveyed as directly as possible at the permissible velocities to obtain the desired results with mini mum noise and greatest economy of power, material, and space. 2. Sudden changes in the direction or velocity of the air should be avoided. When sudden changes are necessary at bends, turning vanes should be used to minimize the pressure loss. 3. Diverging transition pieces should be made as gradual as. practicable. As shown in the section on area nhnngna, losses in abrupt enlargements are high and therefore sucE transitions should be avoided. Hie included angle of divergence for enlarge ment should not exceed 20 deg. Losses in contractions are. low 1. Study the plan of the building and arrange the positions of the supply outlets to provide proper distribution of air within each space. Select outlet sizes from manufacturers' cata log data. 2. Draw a sketch of the most convenient system of ductwork, connecting the supply outlets and return intakes with the cen tral station apparatus, takiog cognizance of the building con struction, avoiding all obstructions in steel work nd equipment, and at the same time maintaining a simple dp**gn 3. Calculate the sizes of all main and branch ducts by one of the procedures given in the following section. 4. Determine the total pressure requirement of the supply and return duct systems. Although the loss in total pressure of each duct run connecting the fan and each supply outlet (or return intake) should be calculated and made the same for all runs, ordinarily only the pressure loss of the duct run apparently having the greatest resistance is referred to as the pressure loss of the duct system. Dampers are relied upon for balancing the system. Design Velocities It is not possible to give specific rules for nelwting duct velocities, but the velocities given in Table 6 have been found to give satisfactory results in designing conventional systems. Since the fan horsepower increases approximately as the square of the velocity, and noise generation increases with static pressure, velocities should be kept low for quiet and economical operation. On the other hand, as evident from Equation 3, at a given flow rate the duct rise increases with decreasing velocity. For multistory buildings, it is gome- times possible to reduce the height between floors by using very small ducts, thereby effecting a considerable reduction in building investment cost. The various space-saving sys tems which are becoming increasingly numerous are discussed in the section High-Velocity Systems in Chapter 19 Central Systems for Air Conditioning. The design of high-velocity ducts is discussed briefly in a later section, Design of High . Velocity Ducts, in this chapter. . '' DESIGN METHODS In the design of air duct systems, three methods are em ployed: (1) velocity-reduction, (2) equal-friction, and (3) static-regain. The three methods and their refinements rep resent different design levels of accuracy and complexity, and they should be selected, therefore, to suit the application. Simple duct systems may be designed as quickly and easily as possible, but for large installations the system static- Air Duct Design 293 Table 6 .... Recommended and Maximum Duct .Velocities for Conventional Systems ftecomnended Velocities, Fpm Designation Heating Coils* Residence* 500 250 450 Schools, Theater*, Public BuQdtngs 500 300 500 Industrial Butidings 500 350 600 Air Washers - Suction Connections Fan Outlets 500 500 500 700 800 1000 1000-1600 1300-2000 1600-2400 Branch Ducts Branch Risers Outdoor Air Intakes* Heating Coils* 700-900 GOO 500 1000-1300 600-900 600-700 1200-1800 800-1000 800 Maximum Velocities, fpa 800 600 1200 300 350 500 600 700 Fan Outlets 500 900 1700 500 500 1000 1500-2200 1700-2800 Branch Risers 800-1200 1100-1600 1300-2200 700-1000 800-1300 1000-1800 650-800 800-1200 1000-1600 Than Tckxstie* are for total face area. Dot the net free area; other veloctbee in are tor net free area. pressure requirement must be determined as precisely as possible, the most accurate method being recommended. Velocity-Reduction Method This method consists of selecting the velocity at the fan discharge and designing for progressively lower velocities in the rnnin at each branch duct. With the selected velocities nnH known air-flow rates, the various duct diameters are read directly from figs. 2 or 3, and the equivalent rectangular sizes are obtained from Table 2. The pressure loss of the run having apparently the highest resistance is determined by Adding the straight pipe, elbow, and transition losses; this total value represents the fan static pressure required for the supply-duct system. The return-air system is sized simi larly, starting with the lowest'velocities at the return intakes and increasing them progressively in the direction of the fan . inlet. Dampers are relied upon for balancing the system. A refinement of this method is to size the several branch ducts to dissipate the pressure available at the entrance to each. The pressure loss of the ductwork between the fan and first branch take-off is subtracted from the now known fan static pressure to obtain the available pressure, at each junc tion. By trial, a branch velocity is found that results in the branch pressure loss being equal to, or somewhat less than, that available. The procedure is repeated for each branch. If the fan is specified so that the static pressure available for the ductwork is known, the method consists of finding, by trial, the velocities in the main duct that will result in a pressure loss equal to the pressure available. The branch ducts are then sized as previously explained if such a refine ment is deemed necessary. ' . The merits of the velocity-reduction method are that (1) duct sizes are determined very easily, and (2) velocities can be limited to those known to be safe from causing noise prob lems. Its weaknesses are: (1) proper choice of velocities re quires experience and .judgment, and (2) the designer cannot highest resistance. Equal-Friction Method The principle of this method is to make the pressure loss per foot of length the same for the entire system. With this method little balancing is required for symmetrical layouts in which all runs have about the same resistance. For lay outs having both short and long runs, the shortest run will require considerable dampering. Usual practice is to select the velocity in the main duct near the fan from the standpoint of noise for the particular application. Since the flow rate (cfm) is known, this estab lishes a value of friction loss per 100 ft of duct in Figs. 2 or 3. This gAmft friction loss value is maintained throughout the design. For example, the flow rate in the main after the first branch take-off is reduced by that handled by the branch. Therefore, proceed vertically downward in Figs. 2 or 3 to the new flow rate value, and read the velocity and diameter. Note that the velocity is reduced by this procedure. An ad vantage of this method is that it automatically reduces the duct velocities in the direction of flow, thereby insuring that noise will not be a problem. The equivalent rectangular size of any diameter is obtained from Table 2. By continuing the procedure, all sections, including branch ducts, are sized from Figs. 2 and 3 at the same friction loss per foot of actual length. After siring the system tho pressure loss of the run having apparently the highest resistance is calculated. In so doing, the pressure losses of all elbows and transitions are included, and are expressed in terms of equivalent length of straight pipe. ... The principal limitation of the equal-friction method is f.hftt. it does not differentiate between runs having several transitions, elbows, etc., and runs having none. Only the actual length of duct is considered; this and the flow rate fix the duct size. Moreover, when computing the system re sistance, care must be exercised that the pressure losses of transitions, elbows, etc., are included and added to the straight pipe losses. ' If the pressure available for the ductwork is known, as it is for packaged equipment, this pressure can be divided by the total equivalent length of the run apparently having the highest resistance to obtain a design friction loss value per foot, for use with Tig. 2 or Fig. 3. Hence, for these applica tions, it is not necessary to select an initial velocity. However, the method then has the weakness that the resistances of fittings must be expressed in terms of equivalent length. Since transitions, elbows, etc., have predominantly dynamic losses, the equivalent length of a particular fitting varies con siderably with its actual size. Note, for example, the values for elbows in Fig. 7 of Chapter 18 are related to duct size, and note also, that the elbow losses in Fig. 9 of this chapter are given in terms of the number of diameters. Hence, when the available pressure is known, the method requires that the duct size be estimated in advance. The calculated duct size should therefore be compared with the initial estimate, and if considerably different, a recalculation should be made using the calculated size. Less dampering is required if the method is modified so that only the m*in duct is sized by the equal-friction method. The fan is selected for this total duct resistance and the pressure available at each branch take-off is found in the 294 CHAPTER 21 1959 Guide manner described for the velocity-reduction method. The pressure available at each branch is divided by its equivalent length, in hundreds of feet, to obtain a design friction loss value for use with Fig. 2 or Fig. 3 in conjunction with the branch flow rate. The branch ducts are therefore sized as nearly as possible to dissipate all of the available pressure. When using this modified method, care should be exercised that the velocities in short branches do not become excessive from a noise standpoint. This is easily guarded against during the design process, because the velocity can be read directly from the friction chart. If it is excessive, move hori zontally to the left on the chart and select a diameter which yields a reasonable velocity. The damper for this run will have to dissipate the excess pressure. Since ductwork at tenuates noise to some extent, the damper should be located as close to the main as possible. Sound treatment for r.his branch should also be considered. An alternative solution may be to revise the duct layout to increase the resistance of the run, for example, by relocating the branch take-off so that the total duct length is increased. . Example 6: (Equal-Friction Method). A duct layout is shown m Fig. 12. Outlets Nos. 1 and 2 deliver 750 cfm each and outlet No. 3 delivers 1000 cfm. Selecting a velocity of 1600 cfm in Section A, size the duct system ana determine its static-pressure requirement. ' Solution: The total cfm to be handled is 2500 cfm. From Fig. 3, with 2500 cfm and 1600 fpm velocity, read a diameter of 17 in. and a friction loss of 02 in. of water per 100 ft. Bv subtraction, the flowrate in Section B is 1750 cfm. Along the 02 friction line m Fig. 3, all of the ducts can be sized immediately because the now rates are known. Results are presented in Table 7. The rectangular equivalents were selected from Table 2 with the objective of having the same duct depth for all three branch runs. ' The duct run to outlet No. 3 has the highest, apparent re sistance'. It is decided to fabricate the elbow in Section C with a radius raUo of 12; hence, from Fig. 8 with H/W = 12, E/W 8. Since W -- 125 ft (15 in.), the additional equivalent length due to the elbow L is 10 ft. The total equivalent length of the run is therefore (20 + 10 + 15 + 10 + 15) = 70 ft. There fore, at 02 per 100 ft the duct resistance is 02 X 0.70 -- 0J4 in, of water. Adding to this the outlet pressure of 0.12 in., the static-pressure requirement of the duct system is 026 in. of water. The design is now complete, and dampers will be relied upon for adjusting the outlets to the design flow rates. If refinement is deemed necessary, the modified mt,hod can be applied to Sections D and E. First, the static pressures avail able at the junctions with the main of the Section D and E branch ducts are obtained. For Section D it is the system pres sure of 026 'minus the friction pressure loss in Section A. The latter is 020 X (20/100) = 0.04; hence, the pressure at the en trance of Section B is 022 in. of water. Deducting the outlet pressure loss of 0.12, that available for the ductwork is 0.10. Assume the equivalent of the branch take-off and the OUTLET NO. 2 Table 7.... Tabulation of Results (Example 6) Section A B C D E Now tat* Cfm 2500 1750 1000 750 750 Fndfpn par too ft In. HjO 0.2 0.2 0.2 0.2 0.2 Dud Die. In. 17.0 14.8 12.0 10.7 10.7 Velocity 1600 1480 1290 1190 1190 Rectangular Duct In. 20 X 12 15 X 12 15 X 8 12 X 8 12 X 8 elbow to be 10 ft each. The total equivalent length of Section D is then (10 + 10 + 10 + 5) = 35, and the friction loss per 100 ft required to dissipate 0.10 in. of water is 0.10 X (100/35) = 029. With this unit friction loss and a flow rate of 750 cfm, Fig. 2 yields a diameter of 10.0 in. and a velocity of 1380 fpm. Section E is sized in a similar manner. The pressure available is 026 minus the friction loss in Sections A and B; hence, 020. With the outlet pressure loss of 0J2 deducted, the available ductwork pressure loss is 0.08 in. Asuming that the branch take-off loss is equivalent to 10 ft of duct, the total equivalent length is 20 ft. The required friction loss is 0.08 X (100/20) = 0.40. With this unit friction loss and a flow rate of 750 cfm, Fig. 2 yields a diameter of 9.4 in. and a velocity of 1580 fpm. An equivalent rectangular size is 9 X 8 in. Comparing these results with those in Table 7, it is evident that the modified method has reduced the size of Section D somewhat and that of Section E considerably. The reduced sizes accomplish more economically what would otherwise have to be done with dampers. Static-Regain Method . Consider a straight run of duct with several branch take offs attached. The flow rate of air along the run is progres sively reduced by the amount diverted into each successive take-off. If, for example, the size of the run were the same throughout its length, the velocity would become progres sively less in accordance with Equation 3. When velocities are reduced, a conversion of velocity pressure into static pressure occurs (as well as a loss in total pressure). The principle of the static-regain method is to rise a duct run so that the increase in static pressure (regain) at each take-off junction just offsets the pressure Ios of the succeeding sec tion of the run. The method provides a convenient means of designing a long run of duct having several take-offs so that essentially the same static pressure exists at the entrance to each branch. If, instead of branch ducts, supply outlets are connected directly to the run, theD essentially the same static pressure will exist behind each outlet. As a consequence, outlet selec tion and system balancing is simplified. The method is par ticularly suited to large installations having several long runs of duct, with each run having many take-offs or supply out lets attached. For this type of application, little or no dampering is ordinarily required to balance the system. The initial velocity in the main duct is selected from noise and pressure loss considerations, and the branch ducts are sized by the modified equal-friction method. If the distance between branch take-offs is either very small or very great, it may not be feasible or economically desirable to design for the same static pressure at each junc tion. In such cases, the method can be used to size the main for either a progressively lower static pressure (net staticpressure loss) or a progressively higher pressure (net staticpressure gain). If no friction or dynamic losses occurred at the junction, there would be no loss in total pressure, and the change in Air Duct Design velocity pressure would be completely converted into a re gain (rise) in static presure, which for standard air would be: ` \4005/ \40Q5/ V' where Pi - theoretical static-pressure regain, inches of water. yl E velocity in main upstream of branch, feet per minute. Ft ~ velocity in downstream of branch, feet per min ute. Under the best practice, 0.7 to 0.8 of the change in velocity pressure is actually recovered, but for practical design an average recovery of 0.5 is assumed. Hence, the actual regain '.-[ty-tey] Design charts based on Equation 13 and rectangular ducts having aspect ratios of 3 to 1 or less are presented in Figs. 14 and 15. The duct length of any section should include the equiv alent length of any elbows or transitions within the section. The charts apply to constructions where regain takes place unaccompanied by radical .change in direction; namely, to straight-through sections of divided-flow fittings. Example 7: (Static-Regain Method). The duct shown in Fig. 13 hnnrliAs 8000 cfm. Determine the duct sizes in Section A, B, C, D, E, F, and G, maintaining an operating pressure of 0.12 in. water in the duct behind each outlet-.- Find the total presure loss of the system. Solution: The following nine steps indicate the solution: 1. Assume the velocity in Section A to be 1500 fpm. This results in an initial duet size of 48 x 16 in. The 16-in. duct depth will be maintained throughout the system. 2. The circular equivalent of a 48 x 16-in. duct is 292 in. (from Table 2), ana with 8000 cfm flowing in thw duct, the friction loss from Fig. 3 is 0.13 in. per 100 ft. - 3. To size the branch ducts, determine the shortest equivalent length of duct up to the first outlet. Section B = 25 ft; Section p = 10 + equivalent length of elbow. Assume the width of the duct in Section P to be 15 in.; therefore H/W -- 15/16 -- 0.94. Also the radius of the elbow should not be less than the width (R/W = 1D0), resulting in an equivalent length L, from Fig. 8, of 10 X (15/12) = 12.5 ft. Equivalent length of Section P = 10 + 125 = 225 ft. Therefore, Section P being shorter than Section B, rise Section F first, firing the same friction rate as in Section A, 0.13 in. per 100 ft. In Fig. 2, with 2000 cfm and a friction rate of 0.13 in., finH an equivalent diameter of 17 in. for Section F. The rectangular equivalent of a 17-in. duct is 15 x 16 in. (from Table 2), resulting in a velocity of 1200 fpm. 295 " l* A B C D E Table 8 .... Tabulation of Results (Example 7) Air Jet* Velocity Volume tengft Cfa Ft Fpm gator Dad In. 1 Nf On Far 100 Promote lots In. In. HjO 8000 6000 4500 3000 1500 40 25 15 26* 15 1500 1500 1300 1040 860 48 X 16 36 X 16 31 X 16 26 X 16 16 X 16 29.2 --' -- -- -- 0.13 -- -- -- -- 0.05 0.03 0 0 0 P 2000 22.5 1200 15 X 16 17 0.13 G 1000 15 900 10 X 16 -- -- Include* 13 equivalent ft for elbow (see Step 7 in BsnmpU 7). .03 0 Note: The shorter equivalent length line is sized first to pre vent velocities in other branches from exceeding recommended values. 4. Loss in Section P -- 0.13 X 0225 -- 0.03 in. water. 5. Since the operating pressure of Outlet 1 is to be the same as that of Outlet 6, theloss in Section B must equal the loss in Section F. Using the Static-Regain Chart, Fig. 15, size Section B for a net loss of 0D3 in. water. The procedure for using these charts is indicated by arrow heads end dashed lines on Fig. 15. Proceed as follows: a. Locate the velocity of the preceding (upstream) duct section along the velocity scale on the left margin (1500 fpm). b. Proceed horizontally to the air volume fthwciaa* (6000 cfm). . c. Proceed parallel to the curved lines to intersect the di agonal base line. d. Go vertically to the net loss desired (0.03 net loss). e. Go horizontally to the air velocity base line. /. Proceed parallel to the curved lines to intersect ordinate for 25-ft duct length. ' g. Move horizontally to the air velocity scale and read the velocity in the downstream section of duct (1500 fpm). 6. This procedure is repeated for Section C except that the no gam or loss line is used in previous Step 5 d. Outlet No. 2 will then have the same static pressure behind it as Outlet No. 1, thus fulfilling the problem condition of the same operating pres sure for all outlets. 7. At this point, the equivalent length of the elbow in Section* D should be estimated. Its width will be somewhat less than that of Section C. Assume W = 26 in.; hence H/W = 16/26 = 05. With a typical radius ratio of 125, from Fig. 8, L/W =6; therefore L = 6 X (26/12) = 13 ft. Adding this to the actual length of Section D results in a total equivalent length of 26 ft. 8. Using the no gam or loss line in Fig. 14, size Sections D, E, and G. Results are listed in Table 8. 9. The total pressure loss of the system is the sum of the losses in Sections A and B (or P) and the outlet operating pres sure: Loss in Section A = 0.13 X 0.40 = 0.05 Loss in Section B (or F) -- 0.03 Outlet Operating Pressure - 0.12 Total Pressure Loss ~ 0.20 in. DESIGN OF HIGH-VELOCITY DUCTS The transmission of air at high velocities, though common in industrial exhaust systems lor many years, has gained wide acceptance in comfort air-conditioning and ventilation systems in the past few years only. This acceptance is due partly to the use of improved fans and of special soundattenuation and control equipment, and partly to improved design and installation methods based upon a better under standing of the general problems connected with the design 296 CHAPTER 21 1959 Guide Air Duct Design l 297 NET LOSS NET SP CAIN .1 fig. 14.... Static-Regain Chart*-For Determining Velocity in Ducts Carrying 0 to 3000 Cftn * fkwd on Cifualkm 11 1. and installation of high-velocity air-conditioning systems.**-" For general information on these systems, the reader is re ferred to Chapter 19--Central Systems for Air Conditioning. The design of high-velocity duct systems involves a com promise between reduction of duCt size and the consequent necessity for higher fan horsepower. While the size of the ducts and hence the air velocities are governed in large part by the available building space, the maximum velocities given later in this section should not be exceeded without careful examination of all factors involved. - The following general rules will prove helpful in Hpjagmng high-velocity duct systems: 1. The same general rules which apply to conventional duct design also apply to high-velocity duct design. (See Section-- Design Methods.) 2. When designing high-velocity systems, static regain must be accounted for. Latest data indicate that approximately 85 percent of the original velocity pressure can be regained. This may easily account for 1 is. water static pressure and, therefore, a method which does not take into consideration static regain will result in the selection of oversized fans and motors. 3. Proper sound control must be provided. To take care of low-frequency fan noise, a sound attenuator must usually be installed after the fan. When acoustic terminal devices are not used, attenuator chambers or sound-lined ducts must be in stalled after mixing valves, in order to attenuate duct and valve noise to acceptable levels. 4. Air velocities in main ducts may vary from 2500 fpm in some installations to over 6000 fpm in others. Corresponding maximum branch-duct velocities will then vary from 2000 fpm to 4500 fpm. One general procedure for duct '*ing used by many de signers is to maintain velocities approximately constant in main riser and trunks until the friction loss reaches 1 in. per 100 feet. When further reductions in duct size take place, velocities are selected to maintain a constant friction loss of 1 in. per 100 feet. Final branches are generally designed with constant area so that decreasing capacity and velocity will allow full static regain. With this procedure the final velocity of an end branch duct may be 1000 fpm, or even lower. The above procedure is not intended to be exclusive, since ducts may also be designed by other methods. (See foregoing section.) 5. Round ducts are used to a great extent in high-velocity systems, because they are easier to seal and do not require bracing or stiffening. However, it is commercially practicable to utilize rectangular ductwork in high-velocity systems. The duct aspect ratio should be kept low and should not exceed 4:1. The duct must be rigidly braced to withstand the static pressure of the system. All longitudinal seams and cross-seams must be made tight- Mastic waling compounds and special tapes are available as less expensive substitutes for positive seals such as soldering or welding. (See Duct Construction Details.) 6. Low-loss take-offs and fittings should be used. Rigid turn ing vanes should be installed in all rectangular duct right-angle elbows. In round ducts, turning vanes should be avoided and long-radius elbows used instead. Both 90-deg and 45-deg duct take-offs are used. However, the use of conical take-offs or A i, I fig..15.... Static-Regain Char1*-For Determining Velocity in Ducts Carrying 3000 to 30,000 Cfm angular take-offs is recommended, in order to keep duet friction as low as possible." 7. Duct dampers are not required in the inlet connections to an acoustic terminal device. Capacity (tampering at each outlet can be adjusted by means of the acoustic terminal damper. A branch duct supplying air to a number of acoustic terminals may be equipped with a branch-line balancing damper as an aid in field balancing. In a single-duct system, the branch-line damper may be manually adjusted. In a dual-duct system, the branch-line balancing damper may be a static-pressure regulating damper controlling the pressure in the branch-line duct. In this manner the branch-duct capacity may be raised or lowered by adjusting the setting on the branch-duct damper. Face dampers on the two decks of a one-fan dual-duct system also may be used as static-pressure regulating dampers. An inlet-vane dam per on the fan is usually effective for system capacity control. Control In primary-air high-velocity systems, it is not necessary to control static pressures in order to prevent static-pressure unbalance, because this system operates with constant air* volume. In all-air high-velocity systems operating with variable air Sow, some control of static pressures may be required in order to prevent static-pressure unbalance, which is a large deviation from design static pressure at the inlet of a terminal, caused by large deviations in air flow. In angle-duct high-velocity systems, operating with changing air volume, the variations in static pressures can be limited by: a. Static-pressure controllers operating dampers in the air- distributing-system. ' b. Static-pressure controllers operating inlet vane dampers on the fan. c. Zoning and changing air-supply temperature in response to static-pressure changes. ' In dual-duct systems, the daily and seasonal variations in beating and cooling loads produce constantly changing de mands for cold and warm air, causing a wide variance in flow and consequently in duct static pressures. It is, therefore, necessary to control the total fan delivery and in some cases the duct static pressure to limit pressure at the terminals. At present, there are three methods used by the industry to control static pressures in dual-duct systems: a. By dampers operated by static-pressure regulators located at critical points in the air-distributing system. The number, arrangement, and location of such dampers and static taps are dictated entirely by the complexity of the air-distributing sys tems, the initial fan pressure, and the particular fan character istics. b. By static-pressure controllers, regulating cold and warm air temperatures in order to limit the variations in the air flow in individual ducts. This method is applicable to centrally zoned systems and may involve an increase io total fan capacity. c. By volume regulators in each individual air-mixing valve or acoustic terminal device. When this method is used, fixed - volumetric delivery is maintained at each outlet, and'the system characteristics remain - constant through the entire range of operation. -. Performance and pressure-volume characteristics of dual duct systems are discussed in the paper by N. S. Shataloff." In the other papers, listed in the reference section of this chapter, may be found further discussions of the types of air conditioning systems which use high-velocity ducts. (Refer ences 16-23 and 25-27.) 298 CHAPTER 21 1959 Guide Table 9.... Recommended Construction for Rectangular Sheet-Metal Ducts High Medium low Pretson Still Steel Steel Akimkwiu U.S. Std. U.S. Std. U-S-Std. B & 5 Gage Goge Gage ' 22 24 26 24 (0.020) Csr RoOed 16 02 Oecf Pimennon n ladei Recommended Condrvcfioa TratwerM Jovits and Bracing Up thru 12 S slip, drive slip, 1 in. pocket lock on 8 ft centers. 20 22 24 22 (0.025) 24 oz 13 thru 18 S slip, drive slip, 1 in. pocket lock on 8 ft centers. 19 thru 30 8 slip, 1 in. pocket lock on 4 ft centers. - S slip, 1 in. pocket lock on 8 ft centers with 1 X 1 X H angles 4 ft from joint. * S slip, 1 in. pocket lock on 8 ft centers with cross break 1 in. stand ing seam on 5 ft centers. 18 20 22 20 (0.032) 32 oz 31 thru 42 1 in standing S cleat, bar slip, pocket lock on 4 ft centers. 1 in. standing S cleat, bar slip, pocket lock on 8 ft centers with 1 X I X H in. angle 4 ft from joint. 1 in. standing seam on 4 ft centers. - Longitudinal standing seam with 1 X 1 X H in* angles on 4 ft centers. ' 43 thru 54 1)4 in. standing S cleat, bar slip, pocket lock on 4 ft centers. 1)4 in. standing 8 cleat, bar slip, pocket lock on 8 ft centers with 1)4 X 1)4 XH in. angles 4 ft from joiot. 1)4 in. standing seam od 3 ft centers. 16 18 20 18 (0.040) 36 oz 55 thru 60 Longitudinal standing seam inside with VH X 1)4 X H in. angles on * 4 ft centers. 61 thru 84 1)4 >Q- standing S cleat, bar slip, pocket lock on 4 ft centers with 1)4 X 1)4 X )i in. angles 4 ft from joint. .. 1)4 in. standing S cleat, bar slip, pocket lock on 8 ft centers with 1)4 X 1)4 X )i in. angles on 2 ft. centers. 1)4 in. standing seam on 3 ft centers. Longitudinal standing seams inside with 1)4 X 1)4 X H in. angles on 2 ft centers. 14 16 18 16 (0.051) 48 os 85 thru 96 1)4 in. standing S cleat, bar slip, pocket lock reinforced with 1)4 X 1)4 XM in., or companion angles on 4 ft centers. t 1)4 in. standing S cleat, bar slip, pocket lock reinforced with 1)4 X 1)4 X He >n- or companion angles on 8 ft centers with 1)4 X 1)4 X K in. angles on 2 ft centers. Longitudinal standing seams inside with 1)4 X 1)4 X % in. angles on 2 ft centers^ ' Over 96 1)4 in. standing S cleat, bar slip, pocket lock reinforced with 2 X 2 X K in. angles, or companion angles on 4 ft centers. 1)4 in- standing S cleat, bar slip, pocket lock reinforced with 2 X 2 X H in. angles, or companion angles on 8 ft centers with 2 X 2 X H in. angles on 2 ft centers. 1)4 in. standing seams with 2 X 2 X )4 in. angles on 2 ft centers. Longitudinal standing seams inside with 2 X 2 X H in. angles on 2 ft centers. Note: (pedal rigidity or stiffms is required, ducte should be contracted ol metal two gage numbers heavier use ZS gage instead of *4 gage. Ducta lurpr .w.w m in. require special field study for and supporting methods. Other knot construction of equivalent mechaninaJ strength and airtightneas may be --pof bracing to ductwork include riveting, bolting, and tack welding. Bracing, stiffening members, or angle connections for eopper duetwurk, where exposed to the weather, should be of brass or aluminum, of suitable thickness for strength. DUCT CONSTRUCTION DETAILS pressures m the duct system for these classifications are: The recommended gages for steel (or iron), aluminum, and copper sheet-metal rectangular ducts are given in Table 9. No general agreement has yet been reached as to the exact limits of the classifications high pressure, medium pressure, and low pressure shown in Table 9. Suggested ranges ef static Low Pressure = up to 1)4 in. water. . Medium Pressure = 1)4 in. to 4 in. water. High Pressure = 4 in. to 8 in. water. * It should be noted that these values are the pressures exist ing in the duct, not the total pressure at the fan. s Air Duct Design 299 Table 10.... Recommended Duct Construction for Round end Hat-Oval Ducts*- b Stef U.S. SM. Gag* Round Rat-oval 24 22 Size Dio or Max Width To 10 in. firoaag on Flat Surface None 22 20 ' 11 to 20 in. 1)4 X 1Y< X H in. angle or l)i X H X H in. channel on 4 ft centers. 20 18 21 to 40 in. 1)4 X 1)4 X H in. angle or 2 X H X H I"' channel on 4 ft centers. 18 16 41 to 60 in. 2 X 2 X )4 in. angle or 2)4 X % X He in- channel on 2 ft centers. 16 14 61 in. and 2 X 2 X % in. angle or 2)4 X over- H X He in. channel on 2 ft centers. All fitting* (bould be of seme gage u pipe or heavier- . b Setiafaetcry for pressure is duct up to 10 iu. water. The recommended gages for steel (or iron) sheet-metal round or fiat-oval ducts are given in Table 10. Steel or iron sheets are specified according to the manufac turers or U. S. Standard Gage System' Aluminum sheets are specified according to the American or Brown & Sharpe Gage System. Copper sheets are usually specified by the weight in ounces per'square foot. Weights of black and galvanized-steel and -iron sheets per square foot of surface .for various gages are given in Table 11. Similar data for 2S aluminum sheets will be found in Table 12. Weights of standard copper sheets are given in Table 13. In calculating the total weight of a given length of ductwork from these tables, it is customary to add 15 percent to the weight to cover hangers, slips, and scrap. Duct bracing or stiffening members should be calcu lated separately. Rectangular ducts are generally constructed by breaking the corners and grooving the longitudinal seam, although some fabricators still use the standing seam. Elbows *nd transformation sections are generally formed with Pittsburgh comer seams because this seam is easier to lock in place than the double seam, but double.seams are equally acceptable. The constructions of these various seams, as well as the types of girth connections, are shown in Fig. 16. The application of the various slips, connections, and bracing is outlined in Table 9. The end dip may be used wherever S slips are recom mended. . Designs M to P of Fig. 16 are for flush-type nearns on duct work where joints are to be concealed. For smooth external appearance the seams may be filled with suitable filler. Screws or rivets used should be of oven-head type. Round and flat-oval ducts should be fabricated in accord ance with the recommendations given in Table 10. Sections may be assembled using beaded couplings, swaged ends, or beaded and crimped small ends. Sections are held in place, using suitable sealers, with sheet-metal screws or rivets, or are welded together. Spiral conduit is acceptable in place of round or flat-oval duct, with recommended gages shown in the following table: Dietaeter, Inches 3 to 8 . 9 to 24 Recommended U. $. Sid. Goge Not lighter than 26 gage Not lighter than 24 gage Table 11 .... Weights of Black and Galvanized Sheets u S. Std. Goge Approximate Thkkneo, In. Steel ln Weight Per Square Foot Ounce* Pound* 30 28 26 24 22 i 20 -8 18 16 14 12 11 10 0.0123 0.0153 0.0184 0.0245 0.0306 0.0368 0.0490 0.0613 0.0766 0.1072 0.1225 0.1379 0.0125 0.0156 0.0188 0.0250 0.0313 0.0375 0.0500 0.0625 0.0781 0.1094 0.1250 0.1406 8 10 12 16 20 24 32 40 50 70 80 90 0.500 0.625 0.750 1.000 1.250 1.500 2.000 2.500 3.125 4.375 5.000 5.625 30 28 26 24 f 22 20 18 16 <5 14 12 11 10 0.0163 0.0193 0.0224 0.0285 0.0346 0.0408 0.0530 0.0653 0.0806 0.1112 0.1265 0.1419 0.0165 0.0196 0.0228 0.0290 0.0353 0.0415 0.0540 0.0665 0.0821 0.1134 0.1290 0.1446 10.5 12.5 14.5 18.5 22.5 26.5 34.5 42.5 52.5 72.5 82.5 92.5 0.656 0.781 0.906 1.156 1.406 1.656 2.156 2.656 3.281 4.531 5.156 5.781 * Galvanized sheets are cased before satvanizinc and are therefore approzj- tnstely 0.004 in. thicker. . Table 12 .... Weights and Thicknesses of 2S Aluminum (Density 0.098 Ib/cu in.) B. * S. Thtcfawn, Indm Decimal - Weight per Square foot Ounce* Pounds 28 0.012 28 0.016 24 0.020 22 0.025 20 0.032 18 0.040 16 0.051 14 .0.064 Ha Ha H* Hi Ht H. Ha . He 2.7 3.6 4.5 5.4 7.2 9.0 11.5 14.4 0.169 0.226 0.282 0.353 0.452 0.563 0.720 0.903 Aluminum sheets of the 2S- and 3S-type alloy and Y* hard temper are readily workable, and can be used for practically all ductwork. The`2S type (commercially pure aluminum) is suitable for all, except very large ducts. For large ducts, where more strength is desired, the 3S alloy with Y* or Yt hard X temper is frequently used. The higher tempers, particularly full hard, do not have the formability of the lower tempers. Joints can be of any of the standard designs, and can be fabricated in the same manner as iron. Repeated sharp bend ing and rebending should be avoided, as aluminum has. a tendency to crack under such treatment. Aluminum of 16 B. & S. gage or heavier can readily be welded by the metallic arc or acetylene process. Riveting is done in the same manner as in iron or steel sheet. Self-tapping screws tend to loosen be cause of the softness of aluminum. The construction of elbows and changes of shape cannot be definitely outlined, because of the varied conditions en- L v. ii-r 300 CHAPTER 21 1959 Guide Table 13 .... Weights and Thicknesses of ct,,.j..j rKn.r.ci...M ' bM to Weight Waighl per Sq H IMdcnes*, Indm Neared Gage No. Oz Lb Decimal Nearest EqoWalcnt Fraction B.&S. Stubs U. S. Sid. 10 0.625 0.0135 He 27 12 0.750 0.0162 Ms ' 26 14 0.875 0.0189 X. 25 16 1.000 0.0216 Hi 23 IS 1.125 0.0243 X2 22 29 27 26 24 23 20 1.250 0.0270 Hi 21 22 24 1.500 0.0324 Hi 20 21 . 28 1.750 0.0378 Hi 19 20 32 2.000 0.0432 X. 17. 19 36 2.250 0.04S6 X. 16 18 40 2.500 0.0540 He 15 17 44 2.750 0.0594 Ms 15 17 48 3.000 0.0648 X. 14' 16 56 3.500 0.0756 H* 13 15 64 4.000 0.0864 X. 11 14 * Variations from thee* weights most be expected in practice. JL 29 28 28 25 24 23 22 20 19 18 17 17 16 14 13 SUP CLP r p ^ " dL S_ _J_ countered in the field, but in general, long-radius elbows and accompanied by decreased turbulence, lower resistance, and a minimum of noise. . Heavy canvas connections are recommended on both the inlet and outlet to all fans. Self-vulcanizing adhesive tapes are available for this purpose and for sealing joints in duct work. Where a fire hazard exists, the material used must satisfy the requirements of any codes or authorities having jurisdiction. The fan discharge connections shown in fig. 16 are marked good, fair, and poor in the order of the amount of turbulence produced. An inspection of the heater connec tions shown in Fig. 16 will readily show that uniform velocity through the heater cannot be expected in the diagram noted poor. When obstructions cannot be avoided, the duct area should never be decreased more than 10 percent, and then a streamlined collar should be used. Larger obstructions re quire an increase in the duct size in order to maintain as nearly uniform velocity as possible. Branch take-offs should always be arranged to cut or dice into the air stream in order to reduce as far as possible the losses in velocity head. Wherever ducts pass through fire walls or connect two fire areas of a building, automatic fire dampers should be pro vided. For design of such dampers and other fire-protective details, see Pamphlet No. 90A of the National Board of Fire Underwriters* . HEAT LOSSES FROM DUCTS In designing duct systems, the heat gains or losses of the ducts can be quite considerable, not only if the duct pagans through unconditioned .space, but also on .long duct-runs within conditioned space. Proper insulation will remedy this situation considerably, but sometimes a redistribution of the supply air is necessary in order to compensate for the heat exchanges that occur. . . The heat loss from a given length of duct can be expressed by: . T y-f <* tCATCR, ftTER, AMD WkSHCft COMCCTONS CASXCMT MXK) owgrrot rrec clmch collar (WUINUII Type BRANCH TAHCOm Rg. 16.... Sheet-Metal Duct and Arrangement Details Q. - UPl (14) where Q = heat loss through duct walls, Btu per hour. ' U -- overall coefficient of beat transfer for the duct wall, Btu per (hour) (square foot) (Fahrenheit degree). P = perimeter of-duct, feet. . ' 1 = length of duct, feet. h " temperature of air entering duct, Fahrenheit. It " temperature of air leaving duct, Fahrenheit. U " temperature of air surrounding duct, Fahrenheit. To obtain' the temperature drop in warm air for a given distance of transmission, or the temperature rise if the duct carries air cooler than the room, through which it paaspa, the following formulas can be used: kiy + 1) - 21| ' (y - U , <>(y ~ 1) + ' (y + 1) (15) (16) 28BAVp , , y - -rfor rectangular ducts or. Air Duct Design . 301 Thickness of (mutation (inches) H 1 1.H .2 12- to 21-in. Duct Diameter.................... 3% 5% 7% 9% 21- to 30-in. Duct Diameter.................... 1% 2% 3% 4% Rg. 17____ Heat Loss Coefficients for Insulated Ducts* 13S>Vp - for round ducts, Ul A = cross-sectional area of duct, square feet. p " density of air, pounds per cubic foot. ' V -- mean velocity of fluid, feet per minute. D =* diameter of round duct, feet. In using Equations 15 and 16, one of the duct air tempera tures will be unknown and will be obtained by substitution of the other known or assumed values. Heat loss coefficients for insulated ducts- with various con ductivities are given in Fig. 17. The conductivities of various materials, which are based on mean temperatures, about 70 F,-wUl be found in Table 4 of Chapter 9. For cases where the mean temperature is other than that at which the test was conducted, a correction should be made. However, in most cases the effect of this'factor will be small and may be ne glected.* . Example 8: Determine the entering air temperature and heat loss for a duct 24 x 36 in. crosa-eection and 70 ft in length, in- sulated with V-in. of a material having a conductivity of 035 Btu at 86 F mean temperature, carrying air at a velocity of 1200 fpui, measured at 70 F, to deliver air at 120 F with air surround ing the duct at 40 F. . Solution: Referring to Fig. 17, the overall beat transmission coefficient is found to be 0.49 Btu. From Table 2, Chapter 3,.the density of air at 70 F and 29.921 in. Hg is found to be 1/13348 -- 09749 lb per cu ft. Substituting these and the other given values in Equation 16, y and h will be as follows: 28.8 X 6 X 1200 X 0-0749 45.3 0.49 X 10 X 70 ' 120(453 + 1) - 80 ' ' 453 -1 Substituting in Equation 14: 1<M, - 0.49 X 10 K--123.7 +--120)\ -401J = 28400 Btu per hr. ' For special considerations which apply to insulation of . ducts in marine installations see Chapter 48. REFERENCES *D. K. Wright, Jr.: ASHVE Reseabch Report No. 1280--A new friction chart for round ducts (ASHVE Transactions, Vol. 51,1945, p.303). .- *L. F. Moody: Friction factors for pipe flow (ASMS Trans actions, Vol. 66, 1944, p. 671). * R. D. Madison and W. R. Elliot: Friction charts for gases including correction for temperature, viscosity and pipe rough ness (ASHVE Journal Section, Heating, Piping and Air Con ditioning, October 1946, p. 107). *F. W. Hutchinson: ASHVE Research Report No. 1469-- Friction losses in round aluminum ducts (ASHVE Trans actions, Vol. 59, 1953, p. 127). * R. G. Huebscher: Friction equivalents for round, square and rectangular ducts (ASHVE Transactions, Vol. 54, 1948, p. 101).. D. W. Locklin: ASHVE Research Report -No. 1405-^Energy losses in 90-degree duct elbows: A survey and analysis of available information (ASHVE Transactions, Vol. 56, 1950, p. 479). * J. R. Weske: Pressure Loss in Ducts with Compound Elbows (National Advisory Committee for Aeronautics, Advance Re stricted Report W-39, February 1943). 'R. D. Madison and J. R. Parker: Pressure losses in reotangttlar elbows (Heating, Piping and Air Conditioning, July, p. 365; August, p. 427; September, p. 483; 1936). . *W. H. Carrier, R. E. Cherne, and W. A. Grant: Modem Air Conditioning, Heating and Ventilating-(Pitman Publishing Corp,, New York, 1950, 2nd ed., p. 248). "Ml C. Stuart, C. F. Warner, and W. C. Roberts: ASHVE Research Report No. 1216--Effect of vanes in reducing loss in elbows in seven-inch square ventilating duct (ASHVE Trans actions, Vol. 48, 1942, p. 409). ' ' "8. F. Gilman: .Pressure losses of divided-flow fittings (ASHAE Transactions, Vol. 61, 1955, p. 281). "G. E. McElroy: Pressure Losses Due to Bends and Area / Changes m Mine Airways (U. S. Bureau of Mines Information Circular l.C. 6663, p- 4). "A. P. Knits and J. R. Fellows: Pressure Losses Resulting from Changes in Cross-Sectional Area in Air Ducts (University of Illinois, Engineering Experiment Station Bulletin No. 300). MR. D. Madison (ed.): Pan Engineering (Buffalo Forge Company, Buffalo, New York, 1948, 5th ed-, p. 124). . u J. R. Henry: Design of Power-Plant Installations: PressureLoss Characteristics of Duct Components (National Advisory Committee for Aeronautics, Advance Restricted Report L4F26, June 1944, L-20S). " L. O. Paul: installing ducts for higher pressures, and Why higher duct velocities? (Heating, Piping and Air Conditioning, April 1953, p. 98 and February 1954, p. 109). . 302 CHAPTER 21 1959 Guide 17 R. D. Tutt: Modem trends in air distribution (Refrigerating Engineering, May 1953, p. 509). "W. W. Kennedy: Design factors in high velocity air dis tribution (Heating and Ventilating, January 1954, p. 83). **J. W. Kreuttner: Can air conditioning be simplified in large buildings? (Heating, Piping and Air Conditioning, August 1954, p. 94). "Gardner Savage: Air conditioning an operating hotel (Heating and Ventilating, September 1954, p. 100). "C. M. Wilson: Handbook on high velocity air distribution (Heating, Piping and Air Conditioning, November 1954, p. 94). Discussions (Heating, Piping and Air Conditioning, December 1954, p. 73; February 1955, p. 69; March 1955, p. 99; June 1955, p. 82). **R. W. Waterfill: Air conditioning of multi-room buildings (ASHAE Transactions, VoL 61,1955, p. 233). B P. B. Gordon: Air conditioning multi-story buildings (Heating, Piping and Air Conditioning, April 1955, p. 112). Discusion (Heating, Piping and Air Conditioning, May 1955, p. 103). " N. S. Shataloff: Elements of dual duct design and per formance (ASHAE Transactions, Vol. 62, 1956, p. 257). N. J. Janisse: How to control high velocity double duct air systems (Heating, Piping and Air Conditioning, November 1955, p. 122 and-December 1955, p. 100). "E. F. Snyder, Jr.: Self-actuated room control from high speed air (ASHAE Transactions, Vol. 62, 1956, p. 295). "High-velocity Air Distribution (collected papers read at Symposium at ASHAE 62nd Annual Meeting, January 25,1956). "C. M. Ashley, S. F. Gilman, and R. A. Church: Branch fitting performance at high velocity (ASHAE Transactions, Vol. 62, 1956, p. 279). National Board of Fire Underwriters Standards (NBFU Pamphlet No. 90, p. 21). . BIBLIOGRAPHY Arid Row (Sm Chapter 4) Hunter Rouse: Elementary Mechanics of Fluids (John Wiley A Sans, Inc., New York, 1946). ' J. C. Hunsakcr and B. G. Rightmire: Engineering Applica tions of Fluid Mechanics (McGraw-Hill Book Co., New York, 1947). Clifford'McClain: Fluid Flow tn Pipes (The Industrial Press, New York, 1952). H. C. Berry: Flow and Fan--Principles of Moving Air Through Ducts (The Industrial Press, New York, 1954). R. J. S. Pigott: Hie Sow of fluids in closed conduits (Me chanical Engineering, Vol. 55, 1933, p. 497). E. Kemler: A study of the data on the flow of fluids in pipes (ASMS Transactions, Vol. 55, 1933, p. 7). Row of Ah tn Owcfi F. C. Houghten, J. B. Schmieler, j. A. Zalovcik, and N. Ivaaovic: ASHVE Research Report No. 1105--Frictional re sistance to the flow of air in straight ducts (ASHVE Trans actions, Vol. 45, 1939, p. 35). ` J. B. Schmieler, F. C. Houghten, and H. T. Olson: ASHVE Research Report No. 1154--Analysis of factors affecting duct friction (ASHVE Transactions, Vol: 46, 1940, p. 193). G. R. Whitn&h and J. V. Bony: Presure loss characteristics of small diameter round duct systems (ASHVE Journal Sec tion, Heating, Piping and Air Conditioning, November 1952, d. 111). . H. G. Conn, W. G. Colborne, and W. G. Brown: ASHVE Research Report No. 1470--Pressure losses in 4-inch diameter galvanised metal duct and fittings (ASHVE Transactions, VoL 59, 1953, p. 139). Prawn Lon in Shows F. L. Busey; Loss of pressure due to elbows in the transmis sion of air through pipes or ducts (ASHVE Transactions, Vol. 19, 1913, p.366). Loring Wirt: New data for the design of elbows in duct sys tems (General Electric Review, Vol. 30, June 1927, p. 286). O. E. Parker: An investigation of pressure losses in air duct elbows (Northeastern University thesis. May 28, 1934). C. H. McLeUan and W. A. Bartlett, Jr.: Investigation of Air Flow tn Right Angle Elbows tn a Rectangular Duct (National Advisory Committee for Aeronautics, Advanced Restricted Report L-328, October 1941). M. C. Stuart, C. F. Warner, and W. C. Roberts: ASHVE Research Report No. 1211--Pressure loss caused by elbows in eight-inch round ventilating duct (ASHVE Transactions, Vol. 48, 1942, p. 335). ' J. R.* Weske: Experimental Investigation of Velocity Dis tributions Downstream of Single Duct Bends (National Ad visory Committee for Aeronautics Technical Note 1471, Jan uary 1948). J. R. Weske: Investigations of the flow in curved ducts at large Reynolds numbers (Applied Mechanics Journal, Decem ber 1948, p. 344). R. K. Guthrie: How much pressure loss in round elbows? (Heating, Piping and Air Conditioning, March 1955, p. 130). R. D. Madison and R. M. Conner: Discussion (Heating, Piping and Air Conditioning, April 1955, p. 89). R. K. Guthrie: Discussion (Heating, Piping and Air Con ditioning, June 1955, p. 81). Pressure ten in Onriifed-ftow FtHmgt H. H. Korst, H. A. Buckley, S. Konso, and R. W. Roose: ASHVE Research Report No. 1392--Fitting losses for ex tended-plenum forced air systems (ASHVE Transactions, Vol. 56, 1950, p. 259). J. W. Holl, S. F. Gilman, R. J. Martin, and S. Konzo: ASHVE Research Repost No. 1430--Pressure losses of take-offs for ex tended-plenum duct systems (ASHVE Transactions, Vol. 57, 1951, p. 419). L. G. Miller, C. H. Pesterfield, and R. J. Waalkes: Resistance of rectangular divided-flow fittings (ASHAE Transactions, Vol. 62, 1956, p. 145). Duct design - L. G. Miller: ASHVE Research Report No. 1050--A rational method of duct design (ASHVE Transactions, Vol. 43, 1937, p. 71). Kirby Walker: Modem thinking applied to duct design (Heating, Piping and Air Conditioning, March 1949, p. 85; April 1949, p. 104; May 1949, p. 91; July 1949, p. 95; September 1949, p. 96; November 1949, p. 97; March 1950, p. 97; May 1950, p. 94). Pointers on air conditioning duct design and installation (Reference Section, Heating and Ventilating, October 1951). Peter Franck: Economical duct layouts (Heating, Piping and Air Conditioning, December 1952, p. 100). F. W. Hutchinson: The Design of Aluminum Duct Systems (Kaiser Aluminum & Chemical Sales, Inc., Oakland, California, 1954). R. W. Ruppert: Nomograph simplifies duct design (HPAC Data Sheet, Heating, Piping and Air Conditioning, July 1955, p. 127). V. J. Turecamo: To size ducts adequately select the right pressure drop (Heating, Piping and Air Conditioning, April 1856, p. 110). R. H. Heilman and R. A.-McArthur: Performance tests of asbestos insulating air ducts (ASHVE Transactions, Vol. 44, 1938, p. 197). j ti 3 | 1 j i I i \ t i i I j: CHAPTER 22 FANS Types, Fan Performance, Fan Laws, Fan Performance Curves, System Characteristics, Fan Arrangements, Fan Control, Motive Power, Fan Selection, Fan Installation, Fan Applications N HEATING, ventilating and air-conditioning practice, defined by the Air Moving and Conditioning Association1 as I the devices used to produce air flow are variously known . follows: as fans, blowers, exhausters or propellers. The ASME Test Code*1 2lim3 4its* 6fa7ns8 9to10those in which the fluid density change 1. Volume handled by a fan is the number of cubic feet of air per minute expressed at fan outlet conditions. does not exceed 7 percent (one psi at atmospheric pressure) and labels as compressors those devices operating beyond 2. Total pressure of a fan is the rise of pressure from fan inlet to fan outlet. that pressure range. Since air conditioning rarely requires pressures of over Vs psi, all such devices will be known as 3. Velocity pressure of a fan is the pressure corresponding to' the average velocity determination from the volume of fans and the air will be considered non-compressible. air Sow at the fan outlet area. ' TYPES Fans are divided into two-general classifications:. (1) centrifugal or radial flow in which the air flows radially through the impeller within a scroll type housing, and (2) axial flow in which the air flows axially through the impeller within a cylinder or ring. Centrifugal fans are further subdivided into types denoted by the curvature or slope of the impeller blades, the angle of which largely determines the operating characteristics. For a given output, a forward inclination of blade indicates a relatively low speed- of operation, and a backward inclina tion, a relatively high speed of operation. Many intermediate forms are also found. Axial-flow fans are subdivided into types differentiated mainly by their enclosures and refinements of impellers and appurtenances. All types vary in shape, number and angles of blades; ratios of hub diameter to impeller diameter; ma terials and methods of fabrication, depending upon design and preference of manufacturer. Tubeaxial and vaneaxial fans, usually used against appreciable resistance, commonly have relatively large hubs and helical blades (the angle varies radially along the blade). The blades may be of uni form thickness, either flat or cambered, and either cast or made of plates; or they may be of air-foil sections, either cast or of double thickness sheet. Streamlining of both im peller and enclosure is common practice. Vaneaxial fans in corporate guide vanes to modify performance and increase efficiency. Propeller fans customarily used for free delivery, or against low resistance, also are found with a variety of blade conformations, but are simple in construction. They are iperely mounted within a {date or ring. ' The fan nomenclature in Fig. 1 has been standardized by the Air Moving and Conditioning Association.1 , FAN PERFORMANCE Fan performance is.a statement of volume, total pressures, static pressures, speed, power input, mechanical efficiency, and static efficiency, at a stated density. These terms are 4. Static pressure of a fan is the total pressure diminished by the fan velocity pressure. - . 5. Power output of a fan is expressed in horsepower and is based on fan volume and the fan total pressure. * 6. Power input to a fan is expressed in horsepower and is measured horsepower delivered to the fan shaft. ' '' ' 7. Mechanical efficiency of a fan is the ratio of power out put to power input. 8. Static efficiency of a fan is the mechanical efficiency multiplied by the ratio of static pressure to the total pressure. 9. Fan outlet area is the'inside area of the fan outlet. 10. Fan inlet area is the inside area of the inlet collar. While the total pressure truly represents the- actual pres sure developed by the fan, the static pressure may best represent the useful pressure for overcoming resistance. In many installations, since the outlet velocity of the:'fan is greater than the duct velocity, some of the velocity pressure may be utilized by conversion to static pressure within the system. However, due to the' uncertainty of the flow at the points of velocity change, the amount of conversion is sel dom known and therefore, most fan tables list only the static pressure as available to overcome the system resist ance. According to the Standard Test Code1 the efficiencies may be determined by the formulas: - Mechanical (total) Efficiency " X 0.0001573 X (cfm) X total pressure (inches water) horsepower input Static Efficiency - 0.0001573 x (cfm) X static pressure (inches water) horsepower input As the static pressure is often more useful than total pres sure, static efficiency is likewise many times more useful than 303 304 CHAPTER 22 1959 Guide mechanical efficiency. However, where a high outlet velocity can be effectively utilized, the static efficiency fails to be a satisfactory measure of performance. Also when a fan operates against no resistance, the static efficiency becomes zero and is meaningless. Under such circumstances, many engineers prefer to use mechanical efficiency. Sound developed by a fan is a characteristic which is be coming increasingly important. Unfortunately, no method has yet been devised for accurately measuring the sound actually discharged into a duct system. The ASHAE Re search Laboratory, in cooperation with the U. S. Navy, has a program underway seeking to find a method. Many manu facturers list the average sound (for various fan operating Prapcfler Fan A propeller fan consists of a propeller or disc wheel within a mounting ring or plate. Tubeaxhl Fan . A tubeaxial fan consists of an axial-flow wheel within a cylinder. Vaneaxkd Fun A. vaneaxial fan consists of an axialflow. wheel within a cylinder, combined with a set of air guide vanes located either before or after the wheel. Centrifugal Fan A centrifugal fan consists of a fan rotor or wheel within a scroll type of hous ing. - total pressure. The laws pertaining to fan size apply only to fans geometrically similar. i.e.. those in which all dimensions are proportional to some linear dimension denoted as size. If the size number is also linearly proportional, it may be used; otherwise, wheel diameter is commonly used as a size criterion. 1. Variation in Fan Speed: Constant Air Density--Constant System (o) Q: Varies as fan speed. (6) P: Varies as square of fan speed. (c) Power: Varies as cube of fan speed. ' 2. Variation in Fan Sice: Constant Tip Speed--Constant Air Density Constant Fan Proportions--Fixed Point of Rating (a) Q: Varies as square of wheel diameter. (fa) P: Remains constant. (e) RPM: Varies inversely as wheel diameter. (d) Power: Varies as square of wheel diameter. 3. Variation in Fan Size: At Constant RPM--Constant Air Density Constant Fan Proportions--Fixed Point of Rating (a) Q: Varies as cube of wheel diameter. (fa) P: Varies as square of wheel diameter. (c) Tip Speed: Varies as wheel diameter. (d) Power: Varies as fifth power of diameter.- 4. Variation in Air Density: Constant Volume--Constant System Fixed Fan Size--Constant Fan Speed (a) Q: Constant. (fa) P: Varies as density. (c) Power: Varies as density. ' 5. Variation in Air Density: Constant Pressure--Constant System ' Fixed Fan Size--Variable Fan Speed (o) Q; Varies inversely as square root of density, (fa) P: Constant. (c) RPM: Varies inversely as square root of density. (d) Power: Varies inversely as square root of density. 6. Variation in Air Density: Constant Weight oj Air--Constant System .Fixed Fan Size--Variable Fan Speed (a) Q: Varies inversely as density. . (b) P: Varies inversely as density. (e) RPM: Varies inversely as density; (d) Power: Varies inversely as square root of density. Fig. 1.... Names and Definitions of Types of Farts Examples 1 to 4 illustrate the application of the preced ing fan laws. conditions) measured at seven stations near the fan. These stations, as specified in the AMCA Test Code,4 are located in a horizontal plane passing through the fan shaft, and are at a distance of one wheel diameter (but not less than 5 ft) from the fan. Such values are useful in comparing the rela tive sound generated by various types and sizes of fans under comparable operating conditions. Example 1: A certain fan delivers 12,000 cfm at a static pressure of 1 in. of water when operating at a speed of 400 rpm and requires an input of 4 hp. If in the same installation 15,000 cfm are desired, what will be the speed, static pressure, and power? . Speed - 400 X - 500 rpm FAN LAWS1. Static pressure = 1 X ( -- J = 1.56 in. The performances of fans of all types follow certain laws which are useful in predicting the effect upon performance of changes in .the conditions of operation, the duty required of the installation, or the size of the equipment due to the 'space, power, or speed limitations. In the following laws, . 500\* (-- ) = 7.81 hp groups 1 to 6, Q = air volume and P = static, velocity, or Example S: A certain fan delivers 12,000 cfm at 70 F and normal barometric pressure (density 0.075 lb-per cubic foot) 305 at a static pressure of 1 in. of water when operating at' 400 rpm, and requires 4 hp. If the air temperature is increased to 200 F (density Gju6u2 ib) and the speed of the fan remains the same, what will be the static pressure and power? 0.0602 _ Static pressure = ,XM -M0"L 0.0602 Power - 4 X - 3.20 bp Example 8: If the speed of the fan of Example i is in creased so as to produce a static pressure of 1 in. of water at at 200 F as at 70 F, what will be the speed, capacity, static power? ' Speed > 400 X 446 rpm Capacity 12,000 x , -- 13.392 cfm (measured at 200 F) . Power -4 X a/- 4.46 hp . y 0.0602 Example 4: If the speed of the fan of the previous ex amples is increased so as to deliver the same weight of air at 200 F as at 70 F,. what will be the speed, capacity, static pressure, and power? 0.075 400 x = 498 n>n> . 14,945 cfm (measured at 200 F) The fan laws stated may be combined to give other overall values. One useful combination is the product of Laws 1 and 3 which gives the following relations: Capacity varies as the ratio of size cubed, times the ratio of the rpm.' Pressure varies as the ratio of size squared, times the ratio of the rpm squared. .. Horsepower varies as the ratio of the size to fifth power, times the ratio of the rpm cubed. Example 6: Assuming that a fan with a 36 in. diameter blast wheel will deliver 12,000 cfm at 70 F at 1 in. static pressure, requiring 4.0 brake hp when operating at 400 rpm, what is the capacity, pressure, and horsepower of a homologous fan having a 45 in. wheel at the same speed? Capacity X 12,000 = 23,400 cfm Static pressure * horsepower - ^0 X X 4 - 12.2 hp " FAN PERFORMANCE CURVES Fan performance curves are the graphical presentation (for constant speed and air density) of the relation of total pressure, static pressure, power input, and mechanical effi ciency, and static efficiency, to actual volume, for the desired range of volumes. Figs. 2, 3 and 4 illustrate performance (sometimes called characteristic) curves of various types of fans. Centrifugal fans? may be roughly divided into three classes: (1) those with the tip of the blades curved forward in the direction of rotation; (2) those with straight radial blades; and (3) those with the tip of the blades inclined backward away from direction of rotation. They are also characterized as slow speed, moderate speed, and high speed types, respectively, although the actual speed range of each may be wide and overlapping. The highest speed type may operate as high as 200 percent of the speed of the lowest speed type, to deliver the same volume of air at the same pressure. The differentiating curvature is always the tip of the blade, since the inlet edge, if inclined, is always curved forward to minimize the shock loss at entrance. Straight radial blades are most frequently found in pressure fans and mAtonal-handling fans. Centrifugal fans produce pressure from two independent sources: (1) from the centrifugal force created by rotating the enclosed air column, and (2) from the kinetic energy im parted to the air by virtue of its velocity leaving the impel ler. This velocity in turn is a combination of rotative velocity of the impeller and air speed relative to the impeller. When the blades tip forward, these two velocities are cumulative, and when backward, oppositional. Thus a fan with forward- curved blades depends less on centrifugal force for its pres sure, and more on velocity pressure conversion in the scroll, with the result that it may run at relatively low speed. Con versely, a fan having backward-curved blades builds up more of its pressure by centrifugal force (a more efficient form of energy transfer) and less by velocity conversion and, therefore, must run at a higher speed. Likewise, a fan having forward-curved blades will produce the greatest capacity of any type of the same size when operating against no re sistance. Since the energy imparted to the air depends on the velocities/ and since the velocities are cumulative with a fan having forward-curved blades, the theoretical energy per pound of air rises rapidly with an increase of air delivery. With the velocities oppositional in the fan having backward- curved blades, the energy per pound of air may decrease, and in a fan having straight blades it is roughly constant. Thus the shape of the horsepower curve definitely identifies the blade angle. . Performance curves of a typical forward-curved blade centrifugal fan are shown in Fig. 2. The pressure rises from free delivery toward no delivery, with a characteristic drop - at low capacities, because a large share of the pressure isx bring generated by conversion of velocity, which is small at low capacity. The maximum efficiency occurs at approxi mately maximum pressure. The horsepower curve reflects the increase in energy by rising rapidly from no delivery to free delivery. The sound is a minimum at maximum effi ciency, and rises toward free delivery as the velocities in crease. Performance curves of a typical backward-curved blade centrifugal fan are shown in Fig. 3. The pressure is con stantly rising from free delivery nearly to point of no de- 306 CHAPTER 22 1959 Guide O I0 20 300s0 60 7oa0 90 n0 mt'CCNT or WIDE OPEN VOLUME Fig. 2....Percentage Performance Curves of a Forward* Curved Blade Centrifugal Fan livery. The horsepower reflects the energy-velocity relation ship by rising to a maximum value as the capacity increases, and then decreasing with further increase in capacity to give a self-limiting horsepower characteristic. The maximum horsepower coincides approximately with the maximum ef ficiency. The sound is again a minimum near maximum effi ciency, but is little or no higher at free delivery than at low -.capacities. . Between the extremes of forward and full-backward- curved blades, there exists a number of intermediate designs which show varying degrees of similarity to the curves in Figs. 2 and 3. A common variation is a fan having modified backward, single, or double-curved blades and equipped with fixed inlet vanes. Such vanes applied to a partially backward-curved impeller give the steep, constantly rising pressure characteristic, and the self-limiting horsepower feature of the full-backward-curve impeller. They also sta bilize the flow entering the impeller when adverse flow con ditions exist in the approach to the inlet. Anal-flow fans develop none of their static pressure by centrifugal force, but all from the change in velocity in pass ing through the impeller, and its conversion into static pres sure. They are thus inherently high-velocity fans, and are very dependent on blade conformation for gbod characteris tics. For that reason, an air-foil section, such as developed in wind tunnels for aircraft work* is frequently used. Since any shape of blade can only be correct for a narrow range of capacity at constant speed, the performance curves for any blade show definite characteristics. To absorb energy, the air must be given a tangential motion in passing the im peller,* and when operating against higher pressures, must have guide vanes (see vaneaxial fans) to obtain best effi ciencies. - . While axial-flow fans are inherently a higher capacity type than centrifugal fans, they, too, may be designed with widely varying characteristics. As with a centrifugal fan, the pres sure rises generally from free delivery to no delivery, but tubeaxial and vaneaxial fans may have a drop in pressure when the capacity decreases below a certain volume, a con dition also found in the case of the centrifugal fan having forward-curved blades. The pressure drop is caused by the same condition for both fans, i.e., the static pressure is largely dependent on conversion of velocity pressure, and velocity pressure is small at low capacity. Tubeaxial and vaneaxial fans may also have performance curves resembling somewhat those of a centrifugal fan with backward-curved blades. Fig. 4 shows the performance curves for a typical design. . The horsepower curve may be flat with a self-limiting characteristic as in a backward-curved blade centrifugal fan, or it may have a generally downward trend from no delivery to free delivery with the maximum at no delivery, contrary to that of a centrifugal fan. The type of guide vanes in a vaneaxial fan has a distinct bearing on the shape of the horsepower curve. The maximum efficiency tends to occur at a percentage of free delivery capacity higher than for a centrifugal fan. The sound curve, which may have a minimum value com parable to centrifugal fans, is again lowest near maximum efficiency, but has a characteristic rise when the fan is operating at low capacities and the stall point of the blade section -is reached. ' Since propeller fans are designed for operation near free delivery, less attention is given the regaining of velocity to static pressure, and the pressure curve rises constantly from free delivery to no delivery. The horsepower is highest at no delivery, and decreases toward free delivery, in contrast to a centrifugal fan. Maximum total efficiency is obtained at a higher percentage of free delivery than for other types. SYSTEM CHARACTERISTICS - Any ventilating system consisting of ductwork, heaters, cur washers, filters, etc., has a system characteristic which is individual to that system, and is independent of any fan which may be applied to the system. This characteristic may be expressed in curve form in exactly the same manner that fan characteristics may be shown. Typical system characteristic curves are shown as A, B, and C in Fig. 5. These curves are drawn to follow the simple parabolic law in which the static pressure or resistance to flow of air varies as the square of the volume flowing through the system. Heating and ventilating systems follow this law very closely and no serious error is introduced by its use. When the characteristic curve of a constant-speed fan of a given size is superimposed upon a system characteristic curve, the relation between the two is at once apparent. The only point common to the two curves is the point at the in- . Fig. 3.... Percentage Performance Curves of a Backward* Curved Blade Centrifugal Fan ; j ' - ; ; ; ' | : i j < 1 | I ] ! | | | | y ^ 3 ; 1 | Fans 307 tersection of the system characteristic curve and the fan characteristic curve, and it is at this point that the combina tion will operate. In Fig. 5, system characteristic, curves A, B, and C cross the fan characteristic curve at points X, Y, and Z. The fan whose curve is shown, when applied to sys tems having characteristic curves A, B, and C, will deliver 10,000, 13,000 or 16,400 cfm, respectively. The curves in Fig. 5 also illustrate the effect of errors that may be made in calculating the resistance of a ventilating system. For instance, if a given system requires 13,000 cfm, and the resistance to flow of the system has been computed as 1.25 in. static pressure, such a system would be repre sented by system characteristic curve B in Fig. 5. If a 100 percent error had been made and the resistance were 2.5 in. instead of 1.25 in.,-then the system characteristic would be as shown in curve A, and would cross the fan curve at 10,000 cfm. Such an error would cause the flow of air to be de creased from a design volume of 13,000 cfm to 10,000 cfm. If the resistance to flow had been overestimated and the resistance actually were 0.625 in., the system characteristic curve would be as shown in curve C, and the fan would de liver 16,400 cfm to the system instead of the design volume of 13,000 cfm. ' In this example, extreme errors have been selected to em phasize the effect the square function of the system charac teristic has in maintaining the fan performance within comparatively narrow limits. In- the first example, a system estimated at half what it should have been, resulted in a drop of 23 percent in volume; and in the second example, a sys tem estimated at twice what it should have been resulted in an increase of 26 percent in volume. In some instances fans may be applied-to variable-flow systems. In such cases, the limiting systems may be plotted and the effect on fan performance examined. For instance, a system - might have a characteristic curve between A, shown in Fig. 5, as one limit, and B as the other limit. The fan performance will then fall between points X and T on the fan curve at a point determined by the system charac teristics at that particular time. If A and B are the limiting characteristic curves of the systems, the fan performance will never be outside the points X or Y. PER CENT OF WIDE OPEN VOLUME * Fig. 4 .... Percentage Performance Curves of an `Axial-Flow Fan FAN ARRANGEMENTS Centrifugal fan arrangements have been standardized by the Air Moving and Conditioning Association. Figs. 6, 7, and 8 show the accepted designation as to arrangement of drive, rotation, discharge, and motor position, for belt drive. Axialflow fans are either belt driven or direct connected, in ac cordance with individual manufacturer's arrangements. Usu ally a choice of antifriction or sleeve bearings is available- FAN CONTROL . In some heating and ventilating systems it is desirable to vary the volume of air handled by the fan. This may be accomplished by a number of methods. Where the change is made infrequently, the pulley or sheave on the driving motor or fan may be changed to vary the speed of the fan arid alter the air volume. Dampers may be placed in the duct system to vary the volume. Variable-speed pulleys or transmissions, such as fan belt change boxes, or electric or hydraulic couplings, may be used to vary the fan speed. Variable-speed motors and variable inlet vanes on fans may also be used to adjust the fan volume. All of these methods will give control. From a power consumption consideration,- a reduction of fan speed is most efficient. Inlet vanes save some power, while dampers save the least. From considera tion of first cost, dampers usually are the lowest in cost. In some installations, adjustments of volume are desirable at various times during the day, or continuously. In others,' an increased supply of air in summer, over that needed in winter, is demanded. The demands in each case will dictate which type of control is most desirable. Where noise is a factor, a lowering of fan speed, if possible, is preferred as a control means, because of the resulting reduction in sound level. In addition to the above types of control, tubeaxial and vaneaxial fans are sometimes made with adjustable blades to permit balancing of the fan against the system, or mak ing seasonal adjustment. - 308 CHAPTER 22 1959 Guide MOTIVE POWER Heating, ventilating, and air-conditioning fans are usuaiiy driven by electric motors, although other prime movers may be used. The small sizes of fans, and especially those operat ing in the higher speed range, are equipped with direct' connected motors. For larger size fans, and those operating at lower speed, V-belt drives are generally used. In selecting the size of motor for operating a fan, it is advisable to select at least the standard size next larger than the fan requirements. Direct-connected motors do not require so great a safety factor as belted units. Justification for liberal power provision exists only in systems where it is possible that larger volumes of air may be required at intervals, and made available by use of bypass dampers, thus greatly reducing the system resistance. If such a sys- tern includes a fan with forward-curved blades, it would be necessary that the motor be sized for the maximum volume and duty. If such a system includes fans with backwardcurved blades, the volume peak would not make it necessary to provide additional motor power. In selecting fans for such 1 I I 1 f * A i N>I-SW, SI No2-SW,Sl M# 3 - SW, SI No3-0W,0l Counter-Clockwise - Ho 4 - SW, SI N7-SW,S1 . No7-DW,DJ Counter-Clockwise . Clockwise Top Angular Down Top Angular Dows Clockwise Bottom Angular Up I i ! < 3 NS-SW,S1 No 0-SW,Sl Rg. 6.... Arrangement of Fan Drives Air. 1, SW, SL For belt drive or direct connection. Wheel overhung. Two bearing* an beae. . Ait. 2, SW, SL For belt drive or diiect canneeticn. Wheel overhung. Bearing* in bracket supported by fan boosing. Air. 3, SW, SL For belt drive or direct connection. One hiring on each ll^* i*^ supported by Not in rive 27 in. diaoater wheel smaller. Air. 2, DW, DL For belt drive or-direct connection. On* bearing on each side and supported by fan housing, Air. 4, SW, SL For direct drive. Wheal overhung on prime mover shaft. No bearings on fan. Bam or equivalent for prime mover. Arr. 7, SW, SL For belt drive or diiect connection. Arrangement No. 3 plus bam for prime mover. Not recommended in sixes 27 in. dianmter and Air; 7, DW. DL For belt drive or direct eocmectioa. Arrangement No. 2 phis bam for prime mover. Arr. S, SW, 8L For belt drive or diiect connection. Arrangement No. 1 Arr. 9, SW, SL For belt drive. Arrangement No. 1 designed for mount ing prime bww on sds of Counter-Clockwise Top. Angular Up Counter-Clockwise Bottom Angular Up Clockwise Top Angnbtr Up Clockwise ' Bottom Angular Down ' Coanta-Cbckwtse Angular Down Note: Direction of Rotation is determined from A# drive ride for either rinjjle or double width or single or double Mel fans. (The driving side of a single Met fan is considered to be the ode opposite the Met regardless of the oefoot location of the drivej for fan inverted for ceiling suspension, * direction of rotation and discharge It determined when fan It retting on floor. Rg. 7.... Designation of Direction of Rotation and Discharge -5 l j! Fans a system, sound ratings should be given careful considera tion^ . WUere a system is constant, and had uu provision for volume change that would materially reduce the resistance, and when the resistance calculations are reasonably precise, there is no necessity for too liberal a motor allowance (even where fans with forward-curved blades are used) if the fan has been property selected. Fig. 5.shows that the system re sistance varies as the square of the volume, and that the fan static pressure varies approximately inversely as the volume, thus greatly offsetting the trend toward both in crease in air delivery and motor load. Reference to Fig. 5 indicates that there is no justification for allowing large spare motor capacity. It is generally more economical to operate motors well loaded. Since the power consumption of fans varies as the cube of the speed, very little starting torque is required of the motor. Refer to Chapter 45 for characteristics of various types of motors. FAN SaECTION The following information is required to select the proper type and size of fan: 1. Capacity in cubic feet per minute. ' 2. Static pressure or system resistance. 3. Air density if other t-han standard. 4. Type of application or service. 5. Arrangement of system. .- 6. Prevailing sound level or use of space served. 7. Nature of load. 8. Type of motive power available. ' In order to facilitate the choice of apparatus, the various fan manufacturers supply fan tables or curves which usually show the following factors for each size of fan operating against a'wide range of static pressures: (1) volume of air in cubic feet per minute (68 F, 50 percent relative humidity, 0.075 lb per cubic foot); (2) outlet velocity; (3) revolutions per minute; (4) brake, horsepower; (5) tip or peripheral speed; and (6) static pressure. The most efficient operating point is usually shown by either boldface or italicized figures in the capacity tables. - Often the service determines the type of fan; When opera tion occurs with little or no resistance, and particularly without a duct system, the propeller fan is indicated for con venience and low cost. When resistance is low the power Rg. 8 ..,. Motor Position, Belt or Chain Drive 309 Table 1.... Good Operating Velocities and Tip Speeds for Ventilating Fans Static Forward Curved Blade Backward Tipped and Double Curved Blade lubeoxiof and Voneextaf Font Water Outlet Velocity Tip Speed fpro Outlet Velocity Tip Speed Fpm Wheel Velocity* K 800-1100 1300-1500 800-1100 2500-3100 1100-1500 H 80O-125C 1600-1850 80O-125C 3000-3750 1250-1700 H 900-145C 1850-2150 900-1450 3400-4250 1400-1900 % 1000-1600 2050-2350 1000-1600 3800-4760 1500-2100 H 1100-175C 2250-2600 1100-175C 4150-5200 1650-2350 % 1200-1900 2450-2850 1200-1900 4500-5600 1800-2500 l 1250-2000 2600-3000 1250-2000 4800-6000 1900-2700 IK 1400-2300 2900-3350 1400-2300 5350-6700 2150-43000 IK 1550-2500 3200-3700 1550-250C 5900-7400 2350-3300 IK 1700-270C 3400-3950 1700-270C 6350-7950 2500-3550 2 1800-2900 3700-4300 1800-2900 6800-8500 2700-3800 2K 1900-3050 3900-4500 1900-3050 7200-9000 2900-4050 2H 2000-3200 4100-4750 2000-3200 7600-9500 3100-4300 3 2200-3500 4500-5200 2200-3500 8300-10500 3300-4600 3K 2400-3800 4900-5650 2400-3800 9000-11500 4 2550-4050 5200-6000 2550-4050 9600-12000 4K 2700-4300 5500-6350 2700-4300 10000-12500 5 2850-4550 5800-6700 2850-4550 10500-13000 5K 2950-4750 6100-7050 2950-4750 11000-13750 6 3100-5000 6400-7400 3100-5000 12000-15000 7 3350-5400 6900-7950 3350-5400 12700-16000 8 3600-5750 7350-8500 3600-5750 13500-1700C 9 3800-6100 7800-9000 3800-6100 14500-18000 10 4000-6400 8200-9450 4000-6400 15000-18500 required is low, and efficiency becomes of secondary im portance. When a duct system is involved the choice is usu- . ally made between a centrifugal fan and a tubeaxial or vaneaxial. At times the capacity-pressure-speed relationship (specific speed)* dictates a choice. Usually, space, efficiency, sound, cost, and serviceability must all be considered.1* In general, centrifugal and axial fans are comparable in effi ciency and sound, but the latter are tighter and require con siderably less space, especially if arranged for straightthrough operation. The comparison cannot be made on the cost of fans only, but the difference in cost of ductwork, mounting, and servicing must be included. A vaneaxial is more efficient and quieter than a tubeaxial, but is more ex pensive, and frequently requires more space. While requir ing less space than the centrifugal, the axial flow fan is inherently less accessible for service. When high-temperature S' air or air containing corrosive elements is being conveyed, motors and bearings should be located outside of the air stream. This requirement may determine the type of fan to be used. Where the system resistance is indefinite or variable, the pressure, horsepower, and noise characteristics of centrifugal fans usually indicate their selection. Under such conditions, a steep and constantly rising pressure curve per mits less variation in. air delivery when the resistance varies. < likewise, a fiat sound curve minimizes the change of moving into a region of increased noise. A fan having a. high effi- 310 CHAPTER 22 1959 Guide ciency over a wide range is more desirable than one which reaches an even higher maximum efficiency, but decreases more rapidly on either side of a narrow range. A self-limiting horsepower curve may permit more accurate selection of motor size. . The selection of size of fan usually involves balancing cost and space against sound and .efficiency. Unless the pressure involved is so high that a smaller fan running at greater speed requires a higher class* of construction, the smallest fan is the cheapest in first cost of the fan only. However, as the cost of the driving equipment is also involved in the total installation cost, fan efficiency must be considered for that reason as well as its bearing on the cost of-operation. In some cases where large fans operate long hours per year, selection at absolute maximum efficiency is indicated. Gen erally, however, the power saving by selecting for optimum efficiency does not justify the extra cost, and a slightly smaller fan gives the best balance of cost and efficiency. Reference to Figs. 2 to 4 shows that all types tend to have a minimum sound near maximum efficiency. When noise is a consideration, therefore, selection approaching maximum efficiency is indicated. Too large a fan may not only cause an unnecessary investment and an increased power con sumption and sound, but may also give faulty performance if it is of a type having an unstable pressure characteristic at low capacity. ` ' Table 1 shows the outlet velocities and impeller tip speeds recognized as good practice for various static pressures for centrifugal, tubeaxial, and vaneaxial fans applied to average heating, ventilating, and air-conditioning applications. Fans for churches, schools, residences, and other buildings having a low prevailing noise level should be selected-for lower than average outlet velocities. FAN INSTALLATION In designing heating, ventilating, and air-conditioning sys tems, the characteristics of the fans available for use there with should not be ignored. If double inlet fans or multiple fans in parallel are used, care must be taken that both inlets have the same free area and general approach conditions. The dimensions of-the ductwork and the size of the vari ous devices whose individual resistances determine the static pressure, dictate the fan selection. Often a minor modifica tion of the system may permit use of a smaller motor, and even a lower class* of fan, with considerable saving of cost. Invariably, the souod generated is affected, as fans operating at high pressure produce more noise than at lower pressure (see Chapter 25). Minimizing the resistance may be the best insurance against noise. On the other hand, sometimes the lowest overall cost results from selecting the minimum size of system equipment, and then installing adequate acoustical and vibration treatment. ' All ducts should be connected to fan outlets and inlets by means of unpainted canvas or other flexible material. Access should be provided in the connections for periodic removal of any accumulations tending to unbalance the rotor. When operating against high resistance, or when ambient noise levels are low, it is preferable to locate the. fan in a room removed from occupied areas or acoustically treated to prevent sound transmission. The lighter building constructions which are common today, make it desirable to mount fans and driving motors on resilient bases designed to prevent transmission of vibrations through floors to the building structure. Conduits, pipes, and other rigid members should not be attached to fans. Noises due to high velocities, abrupt turns, grilles, and other items not connected with the fan, may be present. Treatment of such problems, as well as the design of sound and vibration absorbents, are covered in Chapter 25. FAN APPLICATIONS Many fan applications and the corresponding types of fan commonly used are listed in the following paragraphs. Reference is also made to the chapters where the applica tions are discussed. Central-system supply fans (Chapter 19) are usually of the centrifugal type, since this application requires a wide range of satisfactory and quiet operation against high pressures. They can readily be connected to apparatus of large cross-section on the inlet ride, and to relatively small ducts on the outlet ride. Comparative sizes have been standardized among manu facturers,* and most rating tables cover a range of 700 to 500,000 cfm, and static pressures from Vi to 15 in. of water. Central-system exhaust fans are predominately centrifu gal, but the space conservation of the axial is being in creasingly utilized. Tubeaxial and vaneaxial fan sizes are not yet standardized, but several manufacturers list ca pacities from 2000 to 125,000 cfm, and static pressures up to 3 in. of water. . Exhaust fans are found in all types. Wall fans are pre dominantly of the propeller type, since they operate against little or no resistance. They are listed in capacities from 1000 to 75,000 cfm. They are sometimes incorporated in factory-built penthouses or roof caps, or are provided with matching automatic louvers. Hood-exhaust fans (Chapter 52) involving ductwork, are predominantly centrifugal, especially if handling hot, corrosive, or erosive fumes, where it is best, to keep the bearings and drive remote from the air stream. Otherwise, axial fans are applicable, and where little or no ductwork is involved, propeller fans are suitable. Spraybooth-exhaust fans (Chapter 52) are frequently, centrifugal, especially if built into self-contained booths. Tubeaxial fans lend themselves particularly well to tins application, where ease of cleaning and of suspension in a section of ductwork are advantageous. For such application built-in cleanout doors are desirable. Material handling fans (Chapter 52) are always straight radial (or modified) blade centrifugal type. They are of heavier construction, and have fewer blades and greater clearances than ven tilating fans. Many characteristics are compromised to provide wear resistance and ease of maintenance. They are commonly listed in capacities from 600 to 125,000 cfm, and static pressures up to 18 in. water. Mine-fan applications" vary greatly and require fans ranging from mAlt portable units for local ventilation, to immense slow speed centrifugal fans, often steam-engine- driven, for general or emergency ventilation. Vaneaxial fans are well suited to mine ventilation. For underground loca tion, their compactness saves on cost of excavations, and above ground, their ready reversibility is valuable in emergencies, even if reversal causes a reduction in capacity. Marine fans (Chapter 48) are both centrifugal and vaneaxial types. The latter are particularly well adapted to both combatant and noncombatant ships, where com pactness and light weight are invaluable. 'Unitary systems, i.e., unit beaters, unit ventilators, unit humidifiers, unit air conditioners, unit air coolers, and unit evaporative condensers are equipped with centrifugal or propeller fans, the latter usually being limited to the rela- ' Fans 311 tively gnill suspended type where no 'ductwork is involved. plosive' combinations usually dictate a ' non-sparking fan Fans for units having considerable internal or possible ex in which either the fan, or only those parts which might ternal resistance, are mostly of the forward-curved blade, strike together if not adjusted, are built of non-sparking or so-called mixed-flow centrifugal type. The latter is really materials. Noxious, toxic, radio-active, or pure or valuable a centrifugal type with axial inlets, having a pressure curve gases call for special construction to prevent leakage. This resembling a baekward-curved-blade centrifugal fan. Both usually consists of a welded gas-tight housing, using flanged of these types have the high capacities (in relation to inlet and outlet, and some form of shaft seal. displacement) requisite for a compact unit. Ratings are In most of these special applications, since it is desirable frequently given for these units as separate fans, as well to keep all bearings, drives and motors outside the gas as in conjunction with the various internal resistances. In stream, centrifugal fans are usually used and in arrange multiple units on a common shaft they are listed up to ments 1, 2, 4, or 8 (Fig. 6). The exception is in the case 40,000 cfm capacities. of fans handling explosive mixtures, where propeller or Codling tower fans (Chapter 40) are predominantly of axial fans are permissible when built with explosion-proof the propeller type, but axial types are also used for packed motors and non-ferrous wheels. towers, and occasionally a centrifugal fan is used to supply Fans Handling hot air or gas are generally of the centrif forced draft. ugal types and follow arrangements 1 or 8 so that bearings, Circulating fans are invariably of propeller or disk type, drives and motors are remote from the heat. If of double and are made in a vast variety'of blade shapes and arrange inlet type, they have inlet boxes and long shafts to keep ments. They are designed for pleasing appearance, as well the bearings outside the stream. Propeller or axial types as utility. are rare when the temperature exceeds 150 F. With tem General purpose fans are centrifugal fans of conventional peratures above 600 F special heat-resistant materials may Hf-gjgn, built for service in the lower capacity ranges. They be required for the rotors. In addition to a remote location are built with the fan wheel mounted on the motor shaft, * for the bearings, externa! cooling is frequently required or connected to a self-contained belt-driven arrangement. when the temperature exceeds 200 to 250 F. This is often They are listed in capacities from 100 to 20,000 cfm, and obtained by use of air-cooled or water-cooled jackets. With static pressures up to 1 Vi in. water. anti-friction bearings a head-radiating disc or a small Kitchen fans for domestic use are small propeller fans circulating impeller between the fan and the nearest bearing arranged for window or wall mounting, and with various is sometimes sufficient. Oil lubrication rather than grease useful fixtures. Their capacities range from 300 to 1200 cfm. lubrication is commonly recommended. Attic fans are used during the warm seasons to draw large volumes of outdoor air through a house or other REFERENCES building whenever the indoor temperature-exceeds the out door, and thereby utilize the cooling effect of the relatively cool evening or night air. Research, by the ASHAE31 in dicates that a two to three-minute air change is desirable in the North while in the South, a one-minute change is recommended to provide the additional cooling effect of air motion. Fans may be centrally located in an attic or other unused 1ASME Test Code for Fans (American Society of Mechan ical Engineers, PTC 11-1946). 'Standards, Definitions and terms in use by the fan and blower industry {National Association of Fan Manufacturers Bulletin No. 110, 1952, p. 2). 'Standard test code for centrifugal and axial fans (ASHVE and the National Association of Fan Manufacturers, NAFM Bulletin No. 110, 1952, p. 18). space, or in a hallway, and arranged to draw proportion ately from several rooms; or local window units may be installed in a single room. Central units draw from the living quarters and discharge into the attic, whence the air `Sound measurement test code for centrifugal and axial fans (NAFM Bulletin No. 110, 1952. p. 33). W. H. Hoppmaon II and Fred Lager: Noise ratings of ventilating fans (ASHVE Transactions, Vol. 51, 1945, p. 271). escapes through windows or grilles; or the air may be drawn through grilles into the attic with the fan discharging directiy outdoors. Discharge openings on the lee side are preferred. Attic fans are usually of propeller type, and should be selected to operate at low., velocities' to minimize noise. Noise is more of a problem on local units, but care should be taken to prevent transmission of noise or vibration on all installations, because they operate during sleeping hours. Central units are available in sizes from 3,000 to 30,000 cfm, and window units up to 8,000 cfm. Fans For Special Applications *R. D. Moyer: Fan laws simplify performance calculations {Power, August 1946). *F. L. Buscy: The centrifugal fan (ASHVE Transactions, Vol. 21, 1915, p. 43). TS. A. Moss, C. W. Smith, and W. R. Foote: Energy transfer between a fluid and a rotor for pump and turbine machinery {ASME Transactions, 1941). *E. N. Jacobs, K. E. Ward, and R. M. Pinkerton: The Characteristics of 78 Related Airfoil Sections from Tests in Ike Variable Density Wind Tunnel {National Advisory Com mittee for Aviation Report No. 460). R. M. Pinkerton and Harry Greenberg: Aerodynamic Characteristics of a Large . Number of Airfoils Tested tn the Variable Density Winds' Tunnel {National Advisory Committee for Aeronautics Report No. 678). . Fans are used to handle many gases other than air at norma! temperature. These range from heated air to many types of fumes, vapors, and industrial gases which may be corrosive, explosive, toxic, radio active, or merely noxious. For handling corrosive gases fans should be constructed . of a material suitable for the particular gas being handled,, although at times it is economical to plan on replacing a unit of standard material at more frequent intervals. Ex *M. C. Stuart and J. B. Lusk: The specific characteristics of fans (ASHVE Transactions, Vol. 43, 1937, p. 57). TM W. R. Heath and A. E. Criaui: The axial flow fan and its place in ventilation (ASHVE Transactions, Vol. 50, 1944). "J. J. Walsh: Mine ventilation (ASHVE Transactions, Vol. 23, 1917. p 659). D. Harrington: Mine ventilation and its relation to health and safety (ASHVE Transactions, Vol. 51, 1945, p. 243). UG. B. Helmrieh and G. H. Tuttle: Comfort cooling with ]i 312 CHAPTER 22 1959 Guide attic ventilating fans (ASHVE Transactions, Vol. 40, 1934, p. 155). A. P. Krats and S. Konzo: ASHVE Research Report No. 979--Study of summer cooling in the research residence for the summer of 1933 (ASHVE Transactions, Vol. 40, 1934, p. 167). W. A. Hinton and A. F. Poor: ASHVE Research Report No. 1198--The effect of-attic fan operation on the cooling of a structure (ASHVE Transactions, Vol. 48, 1942, p. 145). W. H. Badgett: The Installation and Use of Attic Fans (Agricultural and Mechanical College of Texas Bulletin No. 52, 1940). W. A. Hinton and W. G. Wanamaker: Some, effects of attic fan operation on comfort: (ASHVE Transactions, Vol. SO, 1944, p. 371). BIBLIOGRAPHY A. H. Church: The Centrifugal Pumps and Blowers (John Wiley A Sons, New -York).' - Fan Engineering (Buffalo Forge Co.). Theodore Baumeister, Jr.: Fans (McGraw-Hill Co, New York). - Curt Keller: The Theory and Performance of Axial Plow Fans, adapted by L. S. Marks and J. R. Weske (McGrawHill Co, New York). AIR HEATING AND COOLING COILS Uses for Coils; Coil Construction and Arrangement: Steam Coils, Water Coils, Direct-Expansion Coils, Flow Arrangement, Applications,; Coil Selection: Heating, Cooling, and Dehumidifying Coils; Heat Transfer and Air-flow Resistance; Performance of Heating and Dry Cooling Coils; Overall Coefficient of . ': Heat Transfer,- Performance of Dehumidifying Coils; Determining Refrigeration Load sBssgss; COILS described in this chapter are used for heating or below them. In making the selection between spray and or iwiling an air stream under -forced convection. surface dehumidifiers, certain advantages of each should Surface-coil equipment may be made up of a number of be considered. The fact that a spray dehumidifier is usu hanks assembled in the field, or the entire assembly may ally designed to deliver nearly saturated air, tends to be factory constructed. The applications of each type of simplify the control problem. In this case the dry-bulb coil are limited to the field within which it is rated. Other - temperature is also the dew point, and hence, a dew-point limitations are imposed by code regulations, by proper control can be arranged by using-a ample duct thermo choice of materials for the fluids used and the condition of stat. Spray dehumidifiers have an advantage over unwetted the air handled, or by an economic analysis of the possible coils of obtaining more air cleaning and odor absorption. alternates for each installation. - On the other hand, coils make possible a closed and balanced USES FOR COILS cooling-water circuit, obviating the unbalanced pumping head, the complication of water-level control, and danger For heating service, coils are used as tempering coils, preheaters, reheaters, or booster beaters. The function of the coils is air heating only, but the apparatus assembly may include means for humidification and air cleaning. Steam or hot water are the usual heating media, although others are used in special cases, such as reheating by means of discharge gas from a refrigerating system. . Coils are used for air cooling with or without accompany ing dehumidification. Examples of cooling applications with out dehumidification are precooling coils using well water or other relatively high temperature water to reduce the from possible floods incidental to multiple-spray dehumidifiere, especially if located on different levels. The use of coils often makes it possible for the same surface to serve for summer cooling and winter heating by circulating cold water in one season and hot water in the other, with conse quent saving in apparatus and piping. Another advantage is that where the surface-coil system can be used with direct expansion of refrigerant, it is comparatively low in initial and operating costs. For comfort-conditioning applications, the regulations of the applicable national and local safety codes should be consulted by the design engineer. load on the refrigerating machinery, or water-cooled coils removing sensible heat in connection with chemical mois COIL CONSTRUCTION AND ARRANGEMENT ture-absorption apparatus. A major portion of coil equip Coils are basically of two types, those consisting of plain ment is designed to handle both sensible cooling and de tubes or pipe, and these haring extended surfaces. The humidification. The assembly usually includes air cleaning former are little used for the applications covered by this means to protect the coil from accumulation of dirt, and to chapter, but are often employed where conditions cause frost keep dust and foreign matter out of the conditioned space. accumulation, and for cooling within spray dehumidifiers. Although cooling and dehumidification are the usual func The heat transmission from air passing over a tube to tions, cooling coils are additionally and purposely wetted a fluid flowing within it is impeded by three resistances. to aid in air cleaning and odor absorption. The first is that from the air to the surface of the tube and The usual coding media used in surface coils are cold is usually called the outside surface- resistance or air-film water or Group I (ASA Classification) refrigerants, but resistance. The second is the resistance to the conduction others are used in special cases. Brines are seldom required of heat through the metal itself. Finally there is another for the range of applications covered by this chapter, al surface or film resistance to the flow of heat between the y though there are cases, where low entering-air temperatures inside surface of the metal and the fluid in the tube. For with large latent heat loads require a refrigerant tempera the applications under consideration both the resistance ture so low that use of water becomes impracticable. Some of the metal wall to beat conduction, and the inside surface ' times, also, brine from an industrial system already installed or film resistance are usually low as compared with the is the only convenient source of refrigeration. - air-side surface resistance. Economy in space, weight, and For combined cooling and dehumidifying, surface coils cost' makes it advantageous to decrease the external sur present an alternate to spray dehumidifiers. For many face resistance, where it is proportionately large, to ap applications it is possible, by proper selection of apparatus, proach that of the tube wall, and that from the tube to choice of air velocities, refrigerant temperatures, etc, to refrigerant. This may be accomplished by increasing the perform the same duty- with either. In a few cases both external surface by means of fins. Sometimes water spray sprays and coils are uged. The coils may then be installed is applied to the same type surface as would have been within the spray chamber, either in series with the sprays used without it. The overall heat transfer is not necessarily ' 313 5 t3 314 CHAPTER 23 1959 Guide increased much, but the water spray may serve other purposes than to increase the flow of heat, such as air and coil cleaning. In fin or extended-surface coils the external surface of the tubes is known as primary, and the fin surface is called sec ondary. The primary surface consists generally of round tubes or pipes which may be staggered, or in some cases placed in line with respect to the air flow. The staggered ar rangement is usually preferred because it obtains a somewhat higher heat transfer value. Numerous types of fin arrange ment are used, the most common of which are spiral, flat, and flat-crinkled or corrugated, all as shown in Fig. 1. While Spni fin* $$3 o o| 44-1444443 00 Z Sp |q 00 Flat csmcstad fins Flit mim fin fig. \ .... Type* of fin-Coi! Arrangement the spiral fin surrounds each tube individually in all cases, the flat types may be continuous (including several rows of tubes), or they may be round or square, with individual fins for each tube. All of these, as well as other- less common types, are in use, the selection for a particular installation being based on economic considerations, space require ments, and resistances of individual designs of coils. A most important factor in the performance of extended- surface coils is the bond between the fin and the tube. An intimate contact between the tube and the fin must be maintained permanently in ordeT to assure a continuation of rated performance after the heating units have been in service for a period of time. In some coils, fins are wound on the tubes under pressure, in order to upset the metal slightly at the fin root, and are then given a coating of solder while the fin and tube are still revolving, for the purpose of assuring a uniform coating of solder. In other types, the spiral fin may be knurled into a shallow groove on the exterior of the tube. The tube may be expanded after the fins are asembled, or the tube-hole flanges of a flat or corrugated fin may be made to override those in the preceding fin and so compress them upon the tube. There are also types of construction where the fin is formed out of the material of the tube itself. - For heating cods, materials most generally used are copper and aluminum: Steel is occasionally used where sodium or calcium chloride brine is circulated in the tubes. Aluminum fins on copper tubes are common construction. Generally speaking, brass does not serve as a satisfactory fin material because of corrosion difficulties. Cooling coils for water or for volatile refrigerants most frequently have aluminum fins and copper tubes, although copper fins on copper tubes are also used. There are many makes of heating and cooling coils of the light-weight extended-surface type for both heating and cooling with tubes commonly Vi, Vs, Vs, and 1 in. outside diameter, and with fins spaced three per inch up to fourteen per inch. The tube spacing generally varies from about 1 to 2Vi in. on centers, depending upon the width of individual fins and on other considerations of performance. Fin spacing should be chosen for the duty to be performed, with special attention being paid to possibility of lint accumulation and, especially in lower temperature dehumidifying, the consideration of frost accumulation. Steam Coils For proper performance of steam heating coils, conden sate and air must be continuously and the steam must be evenly distributed to the individual tubes. This distribution is usually accomplished by individual orifices in the tubes, by distributing plates and orifices in the steam header, or by perforated internal steam-distributing pipes extending into the individual tubes. The latter arrangement has the advantage of distributing the steam throughout the .length of each tube, and is conducive to uniform temperature of delivered air. The tendency of condensate to freeze at the bottom of the coil with cold entering air and light heating loads, is also minimized. This is especially valuable for .out door air preheaters. Water Coils The performance of water coils, for heating or cooling, depends on the elimination of air from the system and proper distribution of water. Air elimination is taken care of in the system piping as described in Chapter 28. To assure a pressure drop sufficient for adequate distribution, but at the same time to provide against excessive pumping head where large water quantities are handled, water coils are provided with various water-circuit arrangements. For instance, a typical coil 18 tubes high and 6 tubes deep in the direction of air flow can be arranged for 6, 9, 18, 24, or 36 parallel water circuits, as conditions may require. Orifices in individual tubes are occasionally employed, but are usually unnecessary as the resistance of individual water circuits is generally sufficient to effect a satisfactory distri bution. In precooting coils nring well water, where there 3 f l I j| 8, Air Heating and Cooling Coils 315 may be considerable sand and other foreign matter in the water, provision for cleaning of individual tubes is of ad vantage. It is important to arrange water coils for complete drainage (see Fig- 2). The drains are usually provided in the water piping at the coil header. d czz 3U 5w^ 4nsn ( cc Fig. 3 .... Direct-Expansion Coil with Hooded System Direct-Expansion Coils Coils for volatile refrigerants present more complex prob lems of fluid distribution, than water, brine, or steam coils. It is desirable that the coil be effectively and uniformly cooled throughout, and necessary that the compressor be protected from entrained, unevaporated refrigerant. There are two types, namely, flooded systems, and thermalexpansion-valve systems, as shown in Figs. 3 and 4. In a flooded coil, the circulation is similar to that in a water tube boiler. The liquid is maintained at the proper level by the action of a float regulator as shown in Fig. 3. The thennalexpansion-valve system depends upon the thermal valve to feed automatically just as much liquid to the coils as is required to maintain the superheat at the coil-suction, out let within predetermined limits, which vary from about 6 to 15 deg. The thermal-valve arrangement is in common use for the type of coils covered by this chapter, while the flooded system is rarely used. . With the flooded system the refrigerant distribution through the tubes depends on properly selecting the length of the feeds, and the head of liquid imposed upon the liquid inlets. The flow of refrigerant from the liquid inlets must be horizontal and upward. .The possibility of gas trapping must be avoided. No auxiliary distributing devices are re quired. In the thermal-valve system, the path of each refrigerant feed from the distributor to the suction header is called a circuit. The length of each circuit should be chosen to provide good heat transfer and return of oil, as well as a reasonable pressure drop across the circuit. The external loading conditions, the tube size, and other factors, in fluence the practical length of a circuit. Because of the various factors involved, the practical length and the ar rangement of the circuits is developed from laboratory tests and the design of coils for units produced in volume are usually verified by additional tests. It is general practice to obtain superheat by suitable design of the coil rather than by use of external heat exchangers or otheT auxiliary devices. To insure reasonably uniform refrigerant distribution in multi-circuit coils, it is common practice to provide a dis tributing means, between valve and coil liquid inlets, to divide the refrigerant equally among the feeds. Such a distributor must be effective for distributing both liquid and vapor, because the entering refrigerant is a mixture of the two. Fig. 5 shows three typical types of distributors. In distributor A the liquid and gas mixture from the thermal valve is led tangentially into a chamber. The coil feed con nections extend outward radially at the top of this chamber. In distributor & the refrigerant is discharged at a high veloc ity through a central jet against the end plate, forming a uni form mixture of gas and liquid within the distributor, from which individual connections are led as shown. In type C the refrigerant enters at high velocity from the thermal valve and is discharged against the end plug in which the individual liquid feeds are closely arranged. These dis tributors can be used in either vertical or horizontal position. There are also other types of headers such as the centrifugal and weir type. The individual liquid connections from the distributor to the coil inlet are commonly made of small diameter tubing, and are all of the same length and diameter in order to impose the same friction between the distributor and the coil. Since the thermal valves act in response to the superheat at the coil outlet, this superheat should be produced with the least possible sacrifice of active evaporat ing-surface- Sometimes a single thermal valve is used per coil. In other cases, multiple valves are used, with the coil divided across the air flow or parallel to the air flow as shown in Fig. 6. The arrangement of Fig. 7 should be avoided, since it offers the disadvantage of unequal load on the two parallel circuits. Control of Coils Chapter 43 discusses methods of controlling air-heating and cooling coils to meet system or space requirements, and factors that should be considered in sizing automatic valves for steam and water coils. Flow Arrangement In all heat transfer processes, the relative directions of flow of the fluids influence the performance of the heattransfer surface. In air-beating and coding coils, the air usually flows at right angles to the tubes. In a coil having only one row in the direction of air flow, the relative direc tions of flow would all be at right angles. In coils having more than one row in the direction of air flow, the media in the tubes may be variously circuited as illustrated for Fig. 4 .... Direct-Expansion Coil with Thermal Valve System water or steam coils in Fig. 8. It is the usual practice to designate a coil that is circuited and employed as in Fig. 8A, as a parallel-flow coil. Figs. 8B and 8C show the general arrangements that are termed counter-flow and cross-flow respectively. Cross flow is common in steam CHAPTER 23 1959 Guide 2 i 1 Fig. 7 .... Arrangement for Depth Control -. fig. 8 .... Flow of Media in Tubes in Relation to Air Flow Air Heating and Cooling Coils 317 Kiting coils, the temperature within the tubes being substantially uniform, And the mean temperature difference the ftme whatever the direction of flow, relative to the air. The parallel and counter-flow arrangements as illus trated m Figs. 8A and SB are common in brine or water coils, with the counter-flow arrangement being the preferred arrangement to secure the advantage of highest possible mean temperature difference. Most direct-expansion coils also follow the general scheme of counter flow but the cir cuiting requirements for proper loading sometimes result in a combination of the other flow arrangements with counter flow in the same coil. Cross flow is generally avoided in the volatile refrigerant coils because of the unequal load ing of the parallel circuits. should be on the downstream side of the coils, made of ample size (not less than 1*4-in. pipe), provided with accessible clean-outs, a deep-sea! trap, and discharge to an indirect waste or storm sewer, so that there will be no possibility that sewer gas may enter the system. Precautions against freezing must be taken with the humidifier piping and drain connections as well as with steam or water coils. Face and bypass dampers have proven to be satisfactory means of capacity reduction for cooling coils using non volatile refrigerants. The use of such face and bypass damper ' Applications Hearing coils in' field-assembled banka are used for a number of purposes as described in Chapter 19. They may be arranged with the air flow vertical or horizontal, al though the latter is more common. For steam hearing, the coils may be set with the tubes vertical or horizontal. In the latter case the coil should be sloped, to provide for condensate drainage. Because of the multi-circuit feed arrangement and the necessity for avoiding air and water pockets, water hearing coils are generally arranged with the tubes horizontal. Certain precautions must be taken against freezing. Where steam coils are used with entering air below freezing temperature, throttling the steam supply may cause freezing of the condensate in the bottom of the coil, if the tubes are of the variety not provided with internal distributing pipes or an equivalent arrangement. Some coils have inner distributing tubes, and also have supply and return headers cast in one piece. In this type of coil the condensate that fonns in the outer tube has resulted from steam fed from the inner tube orifices. This condensate flowing back along the warm inner tube is prevented from freezing. A wide range of modulation at very low temperatures without danger of freezing, is therefore obtained. As an added precaution, with both steam and water coils, the outdoor air inlet dampers are often closed automatically when the fan is stopped to avoid trouble caused by very cold outdoor air drifting in during off periods. fig. 9.... Typical Arrangement of Coding Colls in o ' Central System A typical arrangement of coils is shown in Fig. 9. All of the air should be filtered to prevent dirt, insects, and foreign matter from accumulating on the coils. The cooling coil and humidifier must be provided with a drip pan to catch the condensate formed during the cooling cycle and the excess water from the humidifier. The drain connection arrangements, on volatile refrigerant coils p06es difficult refrigerant control problems which are most severe when a change of setting at the thermostat imposes a rapid change in the dampers at the coils. On many installations, the coil bank is divided into 2, 3, or 4 sections and each section is connected to an individual compressor, or connected to a modulating compressor or compressors which will-Adjust to the load as each succeeding coil section is cut out by the thermostat. The design features of the coil (fin spacing and type of fins, whether circular, fins or plate) determine at what air velocity condensed moisture will be blown off the coil. Water blows off some colls below 400 fpm face velocity, while this does not occur on others at face velocities in excess of 500 fpm. Where there is a likelihood of water being blown off the coil face, eliminator plates should be placed on the downstream side of the coil. Plate-coils are most frequently installed without eliminator {dates. When a number of coil sections are stacked one above another, there is a tendency for the condensate to be carried out into the air stream as it drips from one coil to the next one. In such cases, drip troughs as shown in Fig. 10 are used to collect the water and conduct it to the drain pan. The enclosure around a coil or filter bank should be cor rosion resistant and should have adequate access doors to provide for changing of air filters, cleaning of coils, ad justing expansion valves, oiling motors, etc/ Sometimes cooling and dehumidifying coils are sprayed with water to increase the rate of heat transfer and to provide outlet, air approaching saturation. This arrange ment requires a collecting tank and recirculating pump to maintain water circulation whenever the apparatus is in operation. Fig. 11 illustrates this arrangement with a by pass around the coil. This bypass is often used to facilitate 318 CHAPTER 23 1959 Guide thermostatic control. It is advantageous to direct only re turn air through the bypass rather than a mixture of re turn outdoor air in order to hold the humidity ratio under thermostatic control. . Although both heating and cooling coils are made of sufficient strength to take up expansion and contraction arising within themselves, care should be taken to avoid imposing strains from the piping on the coil connections. (See Chapter 26.) COIL SaECTlON In the selection of a coil it is necessary to consider vari ous factors: 1. The duty required:heating cooling, dehumidifying, and the capacity required to maintain balance with other system components such as compressor equipment in the case of direct expansion coils. 2. Temperature of entering air--dry-bulb only if there is no dehumidification; dry- and wet-bulb if moisture is to be re moved. . . 3. Available heating and cooling media. 4. Space and dimensional-limitations. 5. Air quantity limitations. a given size of pump and pump motor. The performance of a surface heating or cooling coil depends upon correct choice of the original equipment, and upon proper applica tion and maintenance. Coil ratings are based on a uniform face velocity. Inter ference with uniform air flow through the coil will affect performance. Such air flow interference may be caused by air entrance at odd angles or by inadvertent blocking of a portion of the coil face. To obtain rated performance it is necessary that the air quantity be adjusted on the job to that used when selecting the coil, and that it be' kept at this value. The most common cause of a reduction of air quantity are the fouling of the filters and-collection of dirt on the coils. These difficulties can be avoided by proper de sign and regular servicing. There are a number of ways in which coils may be cleaned. A common method is to wash them with water. They can sometimes be brushed and cleaned with a vacuum cleaner. In bad cases of neglect, especially on restaurant jobs where grease and dirt have accumulated, it is sometimes necessary to remove the coils and wash off the accumulation with steam, compressed air and water, or hot water. The best practice, however, is to keep the filters serviced, and to inspect and wash the coils at regular intervals. The proper selection of coils requires an understanding of the requirements of each case, and should be based on an economic analysis of the plant design as a whole. While no general rule can be established for the selection of heat ing or cooling coils, it is possible, nevertheless, to point out the limits of usual practice and to indicate the influence of. the variables involved in the coil selection. Fig. 11____Recirculating Spray System for Cleaning Coils 6. Allowable resistances in air circuit and through tubes. 7. Allowable resistance between the inlet and the outlet of the tube circuits of the coil. 8. Characteristics of individual .coil designs. 9. Individual installation requirements, such as, for ex ample, the type of automatic control to be used. The duties required may be determined from informa tion in Chapter 9, 11, 12, 13, and 19. There may, or may not, be a choice of cooling and heating media, as well as operating temperatures, depending upon' whether the in stallation is new or is in combination with present sources of heating or cooling. Space limitations are dictated by the requirements of individual cases. The air quantity is in fluenced by a number of considerations. The air quantity through heating coils is often made the same as that neces sary to handle the summer cooling load. The air handled may be limited by the use of installed ventilating ducts for air distribution or may be determined by requirements for satisfactory air distribution or ventilation. The resistance through the air circuit influences the fan horsepower and speed. This resistance may be limited to allow the use of a given size of fan motor, or to keep the operating ex pense low, or it may be limited because of sound-level re quirements. The allowable friction through the water or brine circuit may be dictated by the head available from Heating Coils Steam and hot tcater heating coils are usually rated within these limits: Air Face Velocity--200 to 1200 fpm, sometimes up to 1600 fpm. Steam Pressure--2 to 200 psig, sometimes up to 350 psig. Hot Water Temperature--150 to 225 F. * Water Velocity--2 to 6 fps. Individual cases may deviate widely, but the tabulation given herewith will serve as a guide to usual healing instal lation practice: - '' Air Face Velocity--500 to 800 fpm face, 500 being a common figure. Delivered Air Temperature--varies from about 72 F for ven tilation only, to about 150 F for complete heating. Steam Pressure--2 to 10 psig, 5 psig being common. Hot Water Temperature--150 to 225 F. * Water Velocity--2 to 6 fps. Water Quantity--Based on about 20 deg temperature drop through a hot-water coil. . Air Resistance--The total resistance through heating coils is usually limited to from to in. of water tor public Duild- ingB, to about 1 in. for factories. The selection of heating coils is relatively simple as it involves dry-bulb temperatures and sensible heat only, without the complication of simultaneous latent heat loads, as in cooling coils. For a given duty, entering air tempera ture, and steam pressure,- it is possible to select several arrangements of the same design of coil depending upon the relative importance of space, cross-sectional area, and air resistance. ' t ] | i 1 I f t I l I I i ] Air. Heating and Cooling Coils 319 Cooling Coils coil to cool and dehumidify the ventilation air before ad Cooling and dehumidifying cods are usually rated within these limits: mixture with recirculated air. This procedure takes care of one of the main sources of moisture in the usual application. Provision for reheat is required for some industrial applica Entering Air Dry-Bulb--60 to 100 F. tions, and is used for better results on very special com Entering Air Wet-Bulb--50 to 80 F. mercial applications. Air Face Velocities--300 to 800 fpm (sometimes as low as 200 and as high as 1200). In checking the operating results obtained from cooling coils in various air-conditioning installations, it is necessary Volatile Refrigerant Temperatures--25 to 55 F, at coil suc tion outlet. ' Water Temperatures--40 to 65 F. Water Quantities--2 to 6 gpm per ton, or equivalent to a water temperature rise of from 4 to 12 deg. Water Velocity--2 to 6 fps. to keep in mind the influence of the climatic conditions of the various areas encountered. The majority of problems are encountered at light-load conditions when the cooling re quirement is considerably less than at design conditions. In the hot, dry climates, where the outdoor dew points are so constantly low that dehumidifying is not generally The ratio of total to sensible beat removed varies in prac'tice from 1.00 to about 1.65, i.e., sensible heat is from 60 to 100 percent of total, depending on the application. (See Chapter 19.) Since required ratios may demand .wide variations in air velocities, refrigerant temperatures, and coil depth, general rules as to their values may be misleading. On most comfort installations air face velocities between 400 and 600 fpm are frequent, 500 being a common value. Refrigerant temperatures ordinarily vary between 35 and 50 F where cooling is accompanied by dehumidifica tion. Water velocities range from 2 to about 6 fps. When no dehumidification is desired, for which condition the dew point of the entering air is equal to or lower than the cooling coil surface temperature, the coil selection is made on the basis of dry-bulb temperatures and sensible- heat transfer only, the same as with heating coils. It is pos sible also to choose various arrangements of face area, depth, air velocity, etc., for the same duty. "" a problem, the light-load condition does not pose any special problems. In the hot, humid climates, where the outdoor dew points are generally high and close to the dry-bulb tem peratures, the light-load condition has a higher proportion of moisture and a correspondingly lower proportion of sensible heat. These climatic conditions result in higher dew points in the conditioned spaces during the light-load conditions unless some of the special means for controlling the. inside dew points are used. In the geographic locations where warm weather occurs with both high and low dew points, such as around the Great Lakes, the light-load operating conditions with the higher percentage of moisture loading will be encountered less frequently and consistently than in the south nnastal areas. . Care should be taken to avoid freezing at light loads. In general, freezing occurs when the coil surface temperature falls to 32 F. With usual coils for comfort installations, this does not occur unless the evaporating temperature at the coil outlet is about 20 to 25 F. The exact value de Dehumidifying Coils pends on the design of the coil and the amount of loading.. The performance of coils accomplishing both cooling and dehumidification is determined by a series of tests carried on under laboratory conditions. Coil ratings can be pre pared from such laboratory test data to facilitate the selection of coils for cooling and HehutniHifying duty. The Although it is not customary to choose coil and condensing units to balance at low temperatures at peak loads, there is danger of this occurring when the load decreases. This is further aggravated if a bypass is used so that less air is passed through the coil at light loads. coil capacity should be in balance with the capacity of re lated equipment, such as compressors, and the tempera-' ture of the circulating medium. HEAT TRANSFER AND AIR FLOW RESISTANCE The selection of cooling coils for factory-assembled self- The transfer of heat between the heating or cooling contained air conditioners is generally accomplished in con medium and the air stream is influenced by several variables: junction with laboratory testing. The current industry standards call for ratings at 33.4 cfm per thousand Btu of cooling capacity and this is approximately 400 cfm per ton of refrigeration. The use of an entering air condition of 80 F dry-bulb and 67 F wet-bulb is representative of the 1. The temperature difference. ' 2. The design and surface arrangement of the coil. 3. The velocity and character of the air stream. 4. The velocity and character of the medium in the tubes. entering air conditions actually encountered in many com The driving force is usually taken as the logarithmic fort operations because, while the indoor conditions are mean temperature difference for heating or cooling with usually lower than 67 wet-bulb, the introduction of out door air will usually bring the mixture of air to the cool out dehumidification. The rating of cooling coils for com bined cooling and dehumidification is discussed later in ing coil up to an approximation of the 67 wet-bulb enter this chapter. With volatile refrigerants there is often an ing air condition at design conditions. appreciable pressure drop and corresponding change in The selection of cooling coils for field assembled projects evaporating temperature through the refrigerant circuit. is usually accomplished by the use of coil rating tables. The The problem is further complicated by the fact that the practice of selecting coils from the load division indicated refrigerant is evaporating in part of the circuit, and super by the load calculation has worked out satisfactorily for the usual human comfort applications. Additional de sign precautions and refinements are being used for more heating in the remainder. In the case of volatile refrigerants, a cooling coil is tested and rated in conjunction with a spe cific distributing and liquid-metering device, and the ca exacting industrial applications and for improved, results on all types of air conditioning in the more humid areas. pacities are stated for a given superheat condition of leaving vapor. . One of these refinements is the use of a separate The design and surface arrangement of the coil include 320 CHAPTB? 23 1959 Guide Air Heating and Cooling Coils 321 ;l ; such items as materials, type, thickness, height, and spacing U overall coefficient of heat transfer, Btu per (hour) of the fin* and the ratio of this surface to that of the tube . (square foot of external coil surface) (Fahrenheit the use of the staggered or in-line tube arrangement, and degree temperature difference between the fluid provisions to increase the air turbulence such as the use of within the coil and the air flowing over the coil). corrugated instead of flat fins. Staggered tubes increase aim m mean temperature difference; Fahrenheit degrees, be the total heat transfer, as against the in-line arrangement, tween the fluid within the coil and the air passing L *=* thK^"*** of tube wall inches. U B ratio between external and internal surface of the bare tube usually varying from 1.03 to 1.15 for the tube used in typical heating or cooling coils. This ratio R is inserted in the formula in order to place internal fluid coefficient of heat transfer on the basis of external point temperature, the less will be the difference between the leaving dry-bulb temperature and the leaving dew-point tem perature. The first portion of a cooling coil (in the direction of air flow) may function in the same manner as a dry cooling coil. Where the moisture removal starts, the cooling surfaces also and corrugated fins may be more effective than flat. This over it. (This is commonly taken as the logarithmic surface. . design and surface arrangement has a large effect on the air- film heat-transfer resistance. -' The velocity of the air usually considered is the coil face velocity. This bears a varied relation to the actual velocity over the surface, depending upon the individual coil design. As long as a fixed design of cod is under consideration face velocities may be used, but they may be unsatisfactory in comparing different designs, as it is the actual surface ve mean temperature difference.) A ~ external surface area of the given coil, square feet per (square foot of coil face area) (row of coil depth). N " number of rowB of coil depth. ' Overall Coefficient of Heat Transfer While the overall coefficients of heat transfer for plain pipe coils have been defined by numerous tests within close limits, Frequently, when jape or tube walls are thin and of ma terial having high conductivity (as is the case in construction of typical hating and cooling coils) the term L/k in Equa tion 2 becomes negligible and is generally disregarded. (The effect of the term L/k in typical bare-pipe heating or cooling coils seldom exceeds 1 to 2 percent of the overall coefficient.) Thus, in its simplest form, for bare pipe: locity that is significant. The air volume is usually based on the verification of a plain coil design by a series of tests is an standard air at 70 F and a barometric pressure of 29.92 in. accepted commercial practice. The overall coefficients of heat - mercury. .' At the same mam air velocity, varying performance can . transfer for finned coils should always be obtained from tests. The data from a series of tests may be used for purposes of /i + /. be obtained depending upon the turbulence of the air flow extending coil data beyond test range but such data should For finnpH coils the formula* for the overall coefficient of into the coil, and upon the uniformity of distribution of later be verified by tat. ' heat transfer can be conveniently written: . air over the coil face. The latter is very important in ob taining reliable test ratings, and in realizing rated perform Considering any coil, whether of bare pipe or of finned type, .the overall heat-transfer coefficient for a given size and - Rg. 12 .... Performance of Dehumidifying Coil ance in actual installations. The air resistance through the design of coil can always be considered as a combined effect continue the removal of sensible heat, thereby carrying the coils will assist in distributing the air properly, but where of three individual heat-transfer coefficients, namely: f* nf* load due to both. As saturation is approached in the cooling the inlet duct connections are brought in at sharp angles to the coil face, the effect is frequently bad and there may even be reverse air currents through a portion of the coils. 1. The film coefficient of heat transfer between air and the external surface of the coil, usually given in Btu per (hour) (square foot external surface) (Fahrenheit degree tem in which the term tj, called the fin efficiency, is introduced to allow for the resistance to hat flow encountered in the coil, each degree of sensible cooling is approximately matched by a corresponding degree of dew-point decrease. However,. while the sensible heat removal from the dry air remains ap This reduces the capacity, but can be avoided by proper perature difference). fins. proximately constant per degree change, the amount of la layout or by the use of vanes or baffles. 2. The conductivity of the coil material--tube wall, fins, - The term R, in this case, is the ratio of total external sur tent heat removal per degree of dew-point change varies con ' Heat-transfer information on plain pipe coils has been developed and verified through many tests. In the case of finned coils, the beat transfer from the cooling or. heating medium to the'air stream is dependent on so many factors that reliable rating and performance information for any ribs, etc., usually given in Btu per (hour) (square foot of sur- face) (Fahrenheit degree per inch). 3. The film coefficient of heat transfer between the internal surface of the coil and the fluid flowing within the coil.usually given in Btu per (hour) (square foot internal surface) (Fahreneit degree mean temperature difference). face to internal surface. For typical designs of finned coils for heating or cooling, this ratio varies from 10-to 30. Term R is again introduced to place the internal surface coefficient of heat transfer on a basis of external surface. The performances of all heating and dry cooling coils are siderably because moisture content varies widely at different temperatures. ' For example, the following tabulation compares tire amount of moisture removal involved in a reduction of one degree of dew point from 60 to 59 F with the removal from 50 to design of coil must be based upon actual tests of the spe cific coil. Mathematical comparisons of different designs of These three individual coefficients acting in series result in influenced by these same factors. But, when cooling coils operate wet or act as dehumidifying coils, the performance 49 F: j coils on a square foot of surface and face area basis may be misleading. The'selection of finned coils should be made ah overall coefficient of heat transfer in accordance with the basic laws given in Chapters 5 and 9. For a bore-pipe coil the cannot be predicted on the basis of overall coefficients. Daw Point W, X Daw Point W. X 10*U/(fl>) from curves or tables of coil.performance prepared from a series of adequate and reliable tests. There are cases in which the engineer must extend available data or design for a single unique installation. For such purposes the following coil calculations will be useful. overall coefficient of heat transfer, whether for heating or for cooling (without dehumidification), can be expressed by a simplified basic formula as follows: U (2) PERFORMANCE OF DEHUMIDIFYING COILS When the dew point of the air leaving a cooling coil is lower than the dew point of the air entering the coil, some moisture removal has been accomplished. A coil that nor 60 59 . Difference 11.080 10.690 0.390 50 49 Difference 7.658 7.374 0.284 PERFORMANCE OF HEATING AND mally accomplishes (or is designed to accomplish) moisture Tbe abova vahn an firva in TaMa 9, Chapter S. DRY COOLING COILS where removal in addition to sensible-heat cooling is termed a dehumidifying coil. When cooling coils act as dehumidifying coils, the perform ance can be predicted accurately only from tests at a suffi The performance of heating and dry cooling coils depends in general upon: 1. The overall coefficient of heat transfer from the fluid - within the coil to the air it heats or cools. ... 2. The mean temperature difference between the fluid within the coil and the air flowing over the coil. 3. The physical dimensions of the coil. Thus, for any one definite operating condition, the heat ing or cooling capacity of a given coil is expressed by. the following basic formula: q, -U X (At.) X A X N (1) where qi -- total heat transfer of the coil, Btu per (hour) (square ' foot of coil face area). U = overall coefficient of heat transfer, Btu per (hour) (square foot external surface) (Fahrenheit degree moan temperature difference between afr and fluid within the coil). /, -- film coefficient of heat transfer between the internal surface of the coil and the fluid flowing within the coil, Btu per (hour) (square foot internal surface) (Fahren heit degree mean temperature difference between that surface and the average fluid temperature). /, -- film coefficient of heat transfer between air and the external- surface of the coil, Btu per (hour) (square foot external surface) (Fahrenheit degree mean tem perature difference between the mass of air and the external surface). . k = conductivity of material from which the bare pipe is ' constructed, Btu per (hour) (square foot) (Fahrenheit degree per inch thickness). In most air-conditioning processes, the air may be con sidered as a mixture of water vapor and the dry components. Both dry components and the water vapor enter an air conditioning coil at the same dry-bulb temperature; both the dry components and the water vapor lose sensible heat during the contact with the first portion of the coding coil in the same manner as in a dry cooling coil. As the dry-bulb temperature of the mixture approaches the dew point of the water-vapor components, moisture removal starts. The psychrometric path of air through a cooling coil is generally assumed to follow a path similar to that shown in fig. 12. When the dry-bulb temperature of the air mixture in the coil falls below the entering dew-point temperature, moisture removal proceeds. The indications are that the lower the leaving dry-bulb temperature below the entering dew * Rafa'ncal development tad mtiag erf extended air mrJrnf surface, by H. B. PownaU {Btfrigtrotatf Enfinttrtnf, October 193$, p. til). cient number of points to establish the definite performance characteristics of the coil under varying conditions of loading and of entering air. Dehumidifying coils employing volatile refrigerants are generally rated in conjunction with specific refrigerant distributing and flow control equipment. The com bination of the coil with its refrigerant control equipment (such as distributor and expansion valve, and capillary tube or float valve) must be tested at both the higher and lower capacities of its rated range. The lower capacities impose a test on the distributor to provide equal distribution and on the control to modulate without hunting at the lower capaci ties. The higher capacities result in a greater pressure drop through the coif system and a test of the maximum feeding capacity of the flow control device at various head pressures. Most coil manufacturers have their own .methods of pro ducing performance rating tables from a suitable number of coil-performance tests. A method of testing and rating coils, It 322 CHAPTER 23 1959 Guide titled Joint ASRE-ASHAE Standard Method of Testing and Rating Forced-Circulation Air-Cooling and Air-Heating Coda, has been adopted (1958). ' DETERMINING REFRIGERATION LOAD The following determination of the refrigeration load shows a division of the true sensible and latent heat loss of the air, which is accurate within the limitations of the data. These divisions will not correspond to load determination obtained from approximate factors or constants. ' The total refrigeration load g, of a cooling and dehumidifying coil (or air washer) is indicated on Fig. 13 and consists of the following components: . bi u t fig. 13 .... Psychrometric Performance of Cooling , Coil in Central System 1. The sensible heat q. removed from the dry air and moisture in cooling from entering temperature <i to leaving tempera ture ft. 2. The latent heat q, removed to condense the moisture at the dew-point temperature <4 of the entering air. - 3. The heat of subcooling q* removed from the condensate in cooling it from the condensing temperature to the leaving condensate temperature . Items 1, 2, and 3 may be related by ' fli TM 9* + ? + ? (5) If only the total heat value is desired, it may be computed by .. (hi -- hi) -- (ui --. trOh-i (6). where `. ht and ht " enthalpy at points 1 and 2 respectively. and W| " humidity ratio at points 1 and 2 respectively. hi enthalpy of saturated liquid at the final tem perature, f. If a breakdown into latent and sensible heat components is desired, the following relations may be used: The latent heat may be found from where q. -- (toi -- toi)h/, (7) h/t4 * enthalpy at the condensing temperature, - The sensible heat may be shown to be $. + - (ht -- hs) - (uh - ut)h,4 where + (>I -- Ul) (hw - h_,) - (8) A,4 * enthalpy at the condensing temperature, . h -- enthalpy of saturated liquid at condensing tempera ture, U . . The last term in Equation 8 is the heat of subcooling the condensate from the condensing temperature t, to itB final temperature U . Then, q = ftt>! -- ,) (h4 -- Art) (9) AH'values for solving the foregoing equations may be found on the ASHAE Pbtchbometric Chabt and Tables 2 mid 3 of Chapter 3. Example 1; Air enters a coil at 90 F dry-bulb, 75 F wet-bulb; it leaves at 61 F dry-bulb, 58 F wet-bulb; leaving water is assumed to leave at a temperature between the leaving air dew point and coil surface temperature of 54 F. Find the total, la tent, and sensible cooling loads on the coil. Solution: From the ASHAE Pbyckbometbic Chaht, find the following: hi -- 38.42 Btu per lb of dry air. hi 25.10 Btu per lb of dry air. U -- 69 F wet-bulb of entering air. t0i " 0.01525 lb per lb of dry mr. u>! =* 0.00960 lb per lb of dry air. From Table 3, find: - 37.11 Btu per lb. A.* = 22.12 Btu per lb. h/M -- 1054.27 Btu per lb. h,, = 1091.34 Btu per lb. The total heat from Equation 6 is ' q, - (38.42 - 25.10) - (0.01525 - 0.00960) X 22.12 - 1332 - (0.00565 X 22.12) . TM 1332 -- 0.12 = 1320 Btu per lb dry air. The latent heat from Equation 7 is q, " 0.00565 X 1054.27 " 5.96 Btu per ib of dry air. The sensible heat by difference, is q. + q * 5< -- q, TM 13.20 -- 5.96 7.24 Btu per lb of dry air. Or the sensible heat may be computed from Equation 8 as ?.+ ?. (38.42 - 25.10) - (0.00565 X 1091.34) + 0.00565 (37.11 - 22.12) - 13.32 - 6.16 + 0.00565 X 14.99 " 13.32 -- 6.16 + 0.08 -- 7.24 Btu per lb of dry air. The subcooling of the condensate as a part of the sensible beat is indicated by the last term of the equation, 0.08 Btu per lb of dry air. CHAPTER 24 AIR CLEANING Atmospheric Air Cleaners: Airborne Particulate Matter, Viscxws-lmpingement Filters, Dry Air Filters, Electronic Air Cleaners, Air Filter Performance, Selection, Maintenance, Installation, Adsorption of Vapors; Industrial Air and Gas Cleaners: Degree of Cleaning, .Selection, Types, Application, Inertial Separators, Scrubbers, Wet Collectors, Filters, Electrostatic Precipitators, Adsorbers, Absorbers, Combustion Devices AIK cleaning devices remove contaminants from an air g/~\ or gas stream. They are available in a wide range of designs to meet various air cleaning requirements. Degree of removal required, quantity and characteristics of the con taminant to be removed, and conditions of the air or gas stream will have a bearing on the device selected for a given application. Definitions and a discusion of contaminant char acteristics are given in Chapter 7, together with some consid eration of their origin. Air cleaning devices are divided in this chapter into two basic groups: Atmospheric Air Cleaners, described in Part I, and Industrial Air and Gas Cleaners, described in Part II. Atmospheric Air Cleaners are ordinarily used to remove particulates such as are found in outdoor air, and are em ployed in ventilation, air conditioning, and heating systems where dust content seldom exceeds 4 grains per 1000 cu ft of air. Industrial Air and Gas Cleaners are ordinarily used for the heavier concentrations encountered in local exhaust ventila tion where the particulate content (loading) ranges from 100 to 20,000 grains per 1000 cu ft of air. Because of these heavier loadings, atmospheric air cleaners can seldom be used for the control of process aerosols in industrial applications. . PART I--ATMOSPHBHC AIR CLEANERS Conventional air filters and electronic air cleaners are in stalled in air handling systems-to remove dusts. These dusts constitute a mixture of particle sizes within the classification of temporary and permanent impurities listed in Pig. 1, Chap ter 7, including bacteria, pollens, house dusts, and similar al lergens which motivate attacks on persons of allergic sensi tivity.1' * Since the purpose of the filter or cleaner is to free the air of as much existing contamination as practicable, the degree of air cleanliness required should influence the choice of appara tus. Atmospheric dusts are mixtures of particles in all sizes. The removal of these particles and fractions becomes pro gressively difficult as the particle size decreases. Smoke parti cles are of major importance in many applications. Air clean ers will justify their cost through a reduction in housekeeping expense in the ventilated space, by the protection of the equipment in the ventilation system itself, and by providing relatively dust-free air for critical manufacturing processes. Cleaning devices for atmospheric air are classified by the principle employed to collect dirt particles such as impinge ment on viscous coated media, filtration through porous me dia, or electronic air cleaning. In some cases a filter may dis play a combination of these principles. Each type of air cleaner has certain advantages. There are applications where it is desirable to pas air through a series of two or more dif ferent types to obtain optimum results. . AIRBORNE PARTICULATE MATTER Suspensions of particulate matter in the air are called aero - sols and consist of smokes, dusts, mists, and fumes. The characteristics of the aerosols which affect the performance of an sir cleaner include particle size, concentration, shape, den sity, velocity, and surface characteristics. One of the most im portant of these is size. The rate of settling of particles varies approximately as the square of the diameter. Particles larger than 10 microns in diameter settle so rapidly that the concentration of such particles decreases rapidly as the distance from the source increases. Particles less than 1 micron in size settle so slowly that the ordinary convection currents prevent sustained downward motion, and consequently such particles remain in the air for long periods. If particles could be examined through a super microscope having a magnification of 250,000 diameters, a tobacco smoke' particle of 0.1 micron would appear to be 1 in. in diameter, or approximately the size of a golf ball; a soft coal smoke particle 0.3 micron in diameter would appear like a baseball; a ragweed pollen grain of 20 microns in diameter would ap pear 16.5 ft in diameter, while the 50 micron particle (just visible to the naked eye and able to pass through a 270 mesh screen) would appear to be 50 ft in diameter. Consideration of this range in particle size from a golf ball to a sphere 50 ft in diameter will emphasize the difficulty of devising any single test to measure adequately the performance of air cleaning devices under all conditions of service. The particles in the atmosphere can range in size from less than 0.01 micron up to things which are caught by an ordi nary fly screen, such as lint, feathers, and insects. Almost all conceivable shapes and sizes are represented. The material is very commonly soot, ash, soil, lint, smoke, and fumes, but may include particles of almost any inorganic or organic ma terial and even such living organisms as virus, bacteria* and fungus spores. . This wide variety makes it impossible to design one type of cleaner which will be best for all applications. Mechanical Alters of the low-pressure type can remove large particles effectively. Other mechanical filters can remove extremely fine particles, but may be handicapped somewhat by high- pressure drop and cost. Electronic air cleaners have the ability to give high effectiveness on normal atmospheric contamina tion, with a low operating-pressure drop. As a general rule, the renjoval of the coarser dust particles and lint from the ventilating air produces tangible results in 323 324 CHAPTER 24 1959 Guide so far as cleanliness in a house or building is concerned, be cause much of the finer dust remains suspended in the air and is removed from the building by the circulating air. How ever, since some of the fine dusts, especially smoke and fume particles, are undoubtedly deposited by means other than settling, such as electrical or thermal precipitation1' * and by contact, the ability to remove small particles is desirable in an air cleaner if it can be obtained at a reasonable cost. VISCOUS-IMPINGEMBMT TYPE FILTERS The viscous-impingement type of filters consist of relatively coarse media constructed of a suitable fiber, screen, wire, mesh, metal stamping or plates, or a combination of media. The filter may be of the unit type manually-cleaned, the re placeable type, or the automatic moving-curtain type. The medium in a viscous-impingement type filter is usu ally a fiber pack for non-automatic types, or a series of metal plates for automatic self-cleaning types. In either case, the medium is treated with a viscous substance, often an oil or grease, called the adhesive or the saturant, intended to retain dust particles which come in contact with it. Also, in either case, the arrangement is such that the air stream is broken up into many email 'air streams, and these are caused to change direction abruptly a number of times in order to throw the dust particles, by momentum, against the adhesive. Several desirable characteristics of an adhesive for air clean ers of this type are: (1) its surface tension should be such as to produce a homogeneous film or coating on the filter me dium; (2) the viscosity should vary only slightly with nor mal changes of temperature; (3) it should prevent the de velopment of mold spores and bacteria on the filter medium; (4) the liquid should have high capillarity, or ability to wet and retain the dust at all operating temperatures; (5) evap oration should be slight; (6) it should be fire resistant; (7) . it should be odorless. Various fibrous materials have been used as filtering media in unit filters of the viscous-impingement type. These include glass fiber, steel wool, gunilar wool of non-ferrous metals, wire screen, animal hair, hemp fibers, and other materials. In such filters, the medium is often packed more densely on the dis charge than on the approach side, in order to increase the dust-bolding capacity. This results in a selective arrestance of dust with the larger particles nearer the approach face. The arrangement also permits some penetration of lint into (but not through) the filter, so that the amount of lint which can be tolerated on the filter is Alan increased. Due to pltm* sur face area the viscous-impingement type filter, however, may be inferior to some dry types if the air carries a high percent age of lint. The resistance of air filters obviously increases with the rate of air flow through them. Face velocities of about 300 fpm, and resistances in the range from 0.1 to 02 in. water, when the device is new and clean, are usual for ventilation system Alters. Filters designated as high-velocity units are also available. In most instances these filters employ a uniform media pack and give best performance at velocities about 600 fpm. Im pingement type air filters should hold a substantial amount of adhesive so that the dirt collected by the filter will be re tained. The design and construction should also provide a goodly proportion of free space through the media so that high velocities can be used without excessive resistances. The design should assure that the media throughout the thielmegg of the filter will be effectively utilised and therefore, the filter should be designed to minimize the formation of a clogging dirt mat on the filter face. High-velocity filters are apt to be adversely affected if the amount of lint in the air to be cleaned is excessive. The resistance of filters increases with dust or lint loading, and it is the resistance due to this cause that ordinarily neces sitates servicing. The rate of loading obviously depends upon the amount as well as the kind of dust in the air, and for this reason, periods between servicing cannot be predicted with certainty. Manometers are often installed to measure the pressure drop across filter banks and thereby indicate when the filter requires cleaning. The pressure drop tolerated dif fers between operators and system designs. The resistance of a filter bank can be kept desirably low by periodically servic ing some, but not all, of the units in the bank at one time. It is to be noted that a decline in efficiency may be the limiting factor in filter life rather than increased resistance due to load. - The method of cleaning viscous-impingement unit filters differsvfor different types of filters and kinds of dust. Much dry dust or lint can often be removed by rapping the filter. Throw-away filters are constructed of inexpensive mate rials, and are designed to be discarded after one period of use. The frame is frequently a combination of cardboard and Cleanable filters usually have metal frames. Various clean ing methods have been recommended including: air jet, wa ter jet, steam jet, .washing in kerosene, and dipping in an oil. The last may serve both to clean the filter and add the neces sary adhesive. It is not mandatory that unit filters be removed from their metal frames for cleaning outside of the system. Cleaning of unit filters in place is feasible by means of hot water sprayed from a hose or by means of fixed nozzles to accomplish wash ing and adhesive application. Where filters are cleaned in place, provision should be made to collect and drain the water so as to prevent leakage from the filter housing. Moving-Curtain Viscous Filters Moving-curtain air filters are available in two main types. In one type the filtering medium making up the curtain is. considered "permanent" and means are provided to remove the dust from the curtain mechanically. In the other type the curtain consists of a roll of viscous-coated fibrous filter me dium which is not permanent but which is replaced after ac cumulating its dust load. Filters with moving cloth media, not viscous coated, are available esentialiy for lint removal. The medium in the permanent, mechanically cleaned, mov ing-curtain type consists of a series of specially formed metal plates mounted on a pair of chains. The nhainq are mounted on sprockets located at the top and bottom of the filter bous ing, so that the filter medium can be moved as a continuous curtain up one side and down the other side of the sprockets. The arrangement is such that, at the bottom, the medium passes through a bath of special oil which both serves to re move the dirt from the plates, and acts as an adhesive when the cleaned plates next pass through the air stream. The plates forming the filtering medium or curtain usually over lap each other, and due to their special shape, form many small air passages between them. These air passages turn abruptly one or more times in order to give the impingement effect. The medium in the replaceable moving-curtain type filter is supplied in roll form, one roll being sufficient for one to two years of operation in typical applications. The medium forming the moving curtain is unrolled from the supply roll Air Cleaning 325 at the top, is moved down across the air stream where its dust load is accumulated, and then is rewound on a roil at the bottom. Replacement is accomplished by inserting a clean roll of medium at the top and disposing of the loaded dirty roll. In typical replacement medium, moving-curtain filters a cignnl is provided to indicate the end of the medium roll has reached the airstream. Usually provision is also made to stop the automatic curtain-moving mechanism before the end of the curtain is reached. An electrically driven rotating device is usually supplied with a moving-curtain filter. The device may be set to move the curtain periodically, or a special switch, actuated by pres sure drop, may be used to govern its motion. In operation, the resistance of an automatic filter will remain approxi mately constant as long as proper operation is obtained. A . resistance of Vt in. water at a face velocity of 600 fpm is typical of this class. DRY AIR FILTERS The'media in dry filters are usually fabrics or fabric-like materials. Media of wool felt, cotton batting (both glazed and unglazed), cellulose fiber, and other materials have been used commercially. The medium in a filter of this class is usually supported by a wire frame in the form of pockets or V-shaped pleats in order to increase the area exposed to the passage of air. A 2-ft-6quare unit may contain from 15 to 30 sq ft of me dium. Dry air filters, by virtue of the large area of medium used, have a comparatively high lint-holding capacity.-The effi ciency of dry type filters is usually higher than that of viscous impingement filters, while the life of the former based on dust-holding capacity, may be.lower. Dust tends to clog the ' fine pores or openings of dry filters more quickly, thereby .causing a higher rate of resistance.rise than for viscous im pingement filters. Efficiency with very fine particles equiva lent to that of electronic air cleaners is not uncommon"with certain types of dry filters. A comparatively deep bed, Ys to 1 in. thick, of filtering media having individual fibers in the ' order of 1 micron in diameter, is required for such high effi ciency. ' Dry filters may consist of a cleanable medium held in per manent frames, or a throw-away or replaceable filtering me dium held in permanent frames, or the entire filter may be of the throw-away type. Usually- the filtering medium {done is replaced after having collected its full dust load. ELECTRONIC AIR CLEANERS Two principal types of electronic air cleaners are available for air filter application: (1) ionizing type collectors where particles are given a definite charge by passing through an ionization zone, and (2) charged-media type collectors where the energized collecting medium induces a charge on the particles. - Ionizing Type Electronic Air Cleaners Electronic air cleaners use electrostatic precipitation prin ciples to collect particulate matter (see Fig. 1) but operate on much lower voltages than the type commonly used on in dustrial stacks. The designation Electronic Air Cleaner has been standardized to distinguish the class of electrostatic precipitator which alone is suitable for cleaning ventilating air. . In a typical case, a potential of 12,000 volts may be used to create the ionizing field, and some 6000 volts between the plates upon which the precipitation of dust occurs. These voltages, which are capable of momentary shock to person nel similar to that of a spark plug, necessitate some safety measures. A typical arrangement provides means for making the equipment inoperative when any door affording access to high-voltage parts is opened. Operation can be resumed ' only after all doors are closed. The voltages necessary for operation of the equipment are usually obtained by means of electronic high-voltage direct-current power packs operat ing from a 110-120 volt, 60-cycle, single-phase building serv ice. Electric power consumption is about 10 watts per 1000 cfm, phis the approximately 40 watts required to energize the rectifier tube beaters. Air cleaners of this type offer negligible resistance to air flow and, therefore, care must be exercised in arranging the duct approaches on the entering and leaving sides of the cleaners in order that the air flow may be distributed uni formly over the cross-sectional area. The efficiency of the electronic air cleaner is sensitive to air velocity, and the de- Rg. 1____ Diagrammatic Cross-Section of Ionizing Type Electronic Mr Geaner vice itself has much less tendency to rectify the air stream than filters which have higher resistances. In most systems, resistance is deliberately added in the form of a perforated plate, pre-filters, or after-filters for the purpose of obtaining a uniform distribution of air. The resistance, including the baffles or after-filters, is constant and generally ranges from 0.15 to 0.25 in. of water at the'usual velocities of 300 to 400 fpm. Such plates or filters, however, cannot compensate for defects in the duct layout ahead of the cleaner. Suitable screens of no coarser than 16 mesh should be installed across all outdoor air entrances to prevent insects, leaves, bits of paper, and similar material from entering the cleaner. Where lint is present in appreciable quantities, devices for .lint re moval should be installed ahead of the cleaner. Electronic air cleaners of the ionizing type are efficient, low-pressure-drop devices for removing fine dust and smoke particles. They are available in fixed collector-plate and moving collector-plate types. The fixed collector plates are often coated with a special oil as an adhesive. Cleaning is generally accomplished by washing the cells in place with hot water from a water hose or by means of fixed or moving nozzle systems. The bottom of the equipment is made water tight ami provided with a drain. In one moving-plate type, the grounded elements oh which the dirt collects are mounted 326 CHAPTER 24 1959 Guide on chains, and'are alternately dipped in oil and exposed to the air stream. Charged-Media Electronic Air Cleaners The charged-media type air cleaner consists of a dielectric filtering medium, usually arranged in pleats as in typical dry filters. No ionisation means are employed. The dielectric fil tering medium may consist of glass fiber mat, cellulose mat. Effective face area is further defined as that area of the filter face inside the enclosing frame, flanges, or seals, but not corrected for any area occupied by any bracing, and re taining or strengthening grid members, located within the en closing frame. The rated capacity of general ventilation filters is often based on face vdodties in the range of 250 to 520 fpm. Re sistance to air flow, measured in inches of water column, at rated capacity, is generally available from the manufacturer (see Catalog Data Section). A suitable allowance must be made in the system design for increase in resistance as the filter becomes loaded with dust. Fig. 3 indicates the range of resistance to air flow found on tests of four unit filters. Type A is a dense pack used in bacterium control; Type B is a medium pack used for general ventilation work; Type C is a low-resistance unit, for use where low resistance is the im portant factor and maximum deaning efficiencies are not es sential; and Type D is a higb-vdocity viscous-impingement filter. The effectiveness of air deaners in removing a given dust from the air is called efficiency or arrestance. If the effidency is denoted by E, then algebraically E is given by: fig. 2 .... Cross-Section Diagram of Charged Media Type Electronic Air Cleaner or other similar material, and is supported on or in contact with a gridwork consisting of alternately grounded and charged members, the latter usually being held at a potential of 12,000 volts d-c. An intense and non-uniform electrostatic field is thus created through the dielectric medium. Airborne particles approaching the field are polarized and drawn to ward filaments or fibers of the media. The general arrange ment illustrating this type of filter is shown in Fig. 2. The precipitator of this type offers resistance to air flow, when dean, on the order of 0.10 in. of water at 250 fpm veloc ity and, unlike the ionizing type, the resistance of the chargedmedia type electronic cleaner rises as dust is accumulated on the media. Because of these characteristics the Alter tends to equalize the air distribution over the face of the filter, like typical replaceable-media mechanical filters, the charged-me dia precipitator is serviced by replacing the filtering medium. The dielectric properties of the media are impaired when the relative humidity exceeds 70 percent. AIR CLEANER PERFORMANCE AND TESTING Atmospheric dr deaneis are generally rated in terms of the three more critical factors in performance; namely, (1) re sistance vs air flow, (2) efficiency or arrestance vs dust load at design air flow, and, (3) resistance vs dust load at design -air flow. Air flow is expressed in cubic feet per minute and is there fore a function of face velocity and filter size. Face velocity is defined as the average velocity of the air entering the effec tive face area of the deaner and may be expressed by the equation: - . where V - Q/A (1) V = face velocity, feet per minute. Q air flow, cubic feet per minute. A ~ effective face area, square feet. ' where D\ = amount of dust per unit volume in uncle&ned air. Df = amount of dust per unit volume in cleaned air. A number of procedures for evaluating air deaner effi dency have been proposed and are in use. These procedures differ principally in the type of test dust that is used and in the method of measuring the dust content of the entering and leaving air. The numerical value of the arrestance or effidency of an air cleaner may be different for different meth ods of test even when the same test dust is used, and is gen erally different for different test dusts using the same test method. Caution is to be exercised in interpreting published arrestance data, since the test effidency may be different from that obtained in an actual installation, or in the space being supplied with air. The two most common methods for evaluating effidency are: (1) the weight method' in which.the weight concentra tion of dust in the air entering and leaving the filter is meas ured by some suitable means, and (2) the dust spot test in which the dust content of the entering and leaving air is measured in terms of its ability to stain filter paper. The partide count method is not used for efficiency evaluation, except in investigation of filter performance on specific par- Atr Geaning 327 tides such as pollen, or on certain industrial dusts harmful to health Dust particles can be captured on microscope slides by mean* of one of the various kinds of impingement devices. The process is useful if inspection and analysis of dust are de sired, but partide counting is not sufficiently precise for eval uating the effidency of a deaner operating on s heterogene ous dust. Among the weight methods that have been used are the Air Pllter Institute-Code* and modifications of the former ASHVE Code* By the latter test method, a known weight of a prepared dust is injected into air supplied to the filter, and die quantity of dust in the cleaned.air is determined by extracting and weighing the dust from a known volume of cleaned air. Dust extraction from the air is accomplished by drawing the tur through a porous crudble or thimble by means of a high vacuum. The test dust specified in the ASHVE Code is a mixture of coal ash and carbon black. The Air Filter Institute Code, Section I, specifies a test dust as follows: "The test dust mixture consists of 72 percent standardised air cleaner test dust, fine (Arizona road dust, fine); 25 per cent K-l carbon black; and 3 percent No. 7 cotton linters (percentages by weight) " As in the ASHVE Code, the entering concentration (DO is determined by feeding a known weight of the prepared test dust. The concentration of dust in the air leaving the filter (Dt) is determined by passing the entire air flow through a high-efficiency filtering blanket known as an absolute .filter, the gain in weight of which is measured. Test data and results are presented on standardized forms made available by the Air Filter Institute. The dust-spot or discoloration method df test for aircleaner efficiency was developed at the National Bureau of Standards.1 In effect, this method is based on a comparison of the'volumes of air before and after cleaning by the filter that must be drawn through unit areas of suitable filter paper to' yield dust spots of equal opacity to transmitted light as de termined by means of a photometer. For example, if equal opacities are obtained when the amount of air sampled, per unit area of dust spot, is four times as great for the down stream paper as for the upstream paper, the efficiency of.the filter is considered to be 75 percent, since the dustiness of the cleaned air, as measured by change in opacity, is one-fourth that of the uncleaned air. To obtain equal opacities, samples may be drawn at equal rates'for equal times through un equal spot areas, or at equal rates through equal areas for unequal times, as best suits the circumstances. Tests may be made with atmospheric air, or with an artificial dust dispersed in the air stream. Dust-holding capacity is defined as the amount of dust which a filter can retain and have'a resistance less than some arbitrary value. The term applies only to fixed-type air cleaners. Under the AFI* and the former ASHVE* procedures dust-holding capacity is defined as the product of the weight of dust reaching the filter and the average efficiency at a spec ified resistance and air flow. Dust loading and arrestance determinations are made simultaneously, arrestance and re sistance being determined for each increment of feed with the results plotted against weight of dust fed or against accumu lated load in the filter. ; Dirt-loading measurements are made at the National Bu reau of Standards' by feeding a mixture of 4 percent cotton hnterg and 96 percent Cottrell precipitate (by weight) to the test filter. The two ingredients are separately dispersed into the air stream, using two aspirating-type injectors. The meas urements show the relationship between the pressure drop and the weight of dirt mixture received at the filter. The curves in Fig. 4 illustrate the difference in the dirt-loading characteristics of two filters, one a viscous-impingement type and the other a dry filter with an extended-surface cellulosefiber medium, with dust and with lint. SRECTION AND MAINTENANCE To evaluate filters and air cleaners properly for a particu lar application, two factors should be carefully weighed: (1) the degree of air cleanliness required and (2) disposal of the dirt after it is removed from the air. These factors affect ini tial costs, operating costs, and the extent of maintenance that will be required. Savings that accrue through reduction in housekeeping expenses, protection of valuable property and equipment, ability to carry on dust-free manufacturing proc- ' esses, improved working conditions, and even health benefits should be credited against the cost of installing and operating an adequate system. The capacity and physical size of the unit required may emphasize the need for self-cleaning fea tures; Operating costs, predicted life, and efficiency are more important than first cost, because air cleaning is a continu ing process. ' While electronic air cleaners have a higher first cost, they exhibit very high efficiencies in cleaning atmospheric air, due largely to their ability to remove fine dust which shows no gravitational effect. They are equally effective on coolant oil mists from high-speed cutting and grinding machines. Sys tem resistance remains unchanged as dirt is being collected, and the resulting residue is disposed of directly to prepare the . equipment for further duty. The charged-media type cleaners are less effective than the ionizing type, but are appreciably better than mechanical filters in the matter of small particle collection. The advantage of the moving-curtain impingement type filter consists in the small amount of attention which it requires. Such devices are therefore to be recommended where labor is scarce, or where reliable and frequent atten tion to filters cannot be assumed. The constant pressure drop of this type of filter is an advantage. The first cost is substantially greater than that of unit filters, and the dust arrestance may not be any higher. Unit filters constitute the majority of air cleaners now in use, and some choice is possible between the types avail- 328 CHAPTER 24 1959 Guide able. Where lint in an eminently dry state predominates, a .dry filter obviously may be preferable to other types because of its lintrholding capacity. If the lint is greasy, or if oil vapor exists in the air, the dry filter, if it is of the deanable -type, may be troublesome, since grease tends to nift-V* it difficult to clean. Most dry types, however, employ a throw-away type of medium which is held in permanent metal frames so that the difficulty of cleaning the medium is avoided. Some dry filters are capable of high efficiencies, compared to other unit filters on fine particles, but their dust-holding capacity for such dust may be inferior to that of the viscous-impingement type. Viscous-impingement unit filters are practically standard in sue, and their overall dimensions are small when com pared with their ratings. Throw-away units are often installed in series so that the one in front, which usually becomes plugged with lint, - can be discarded, after which the downstream unit is moved to the front and replaced by a new unit. Viscous-impingement unit filters do not have efficiencies as high as can be expected with some other types of unit filters, but their first cost and upkeep are generally lower, whether of the cleanable or the throw-away type. They require more careful attention than the moving-curtain type if the resistance is to be maintained within reasonable limits. . FILTER INSTALLATION Many air cleaners are available in units of convenient size for handling when installing, cleaning, or replacing. Such units are usually designated as filters or unit filters. A typical unit filter may be 20 in. square and from one .to several inches thick, depending on the manufacture and proposed use. In large systems, a number of such 'units are installed adjacent to. each other and collectively called a bank of filters. Air cleaners are commonly installed in the outdoor-air in take ducts of buildings, and generally in the recirculating and bypass air ducts as well. Cleaners are logically placed ahead of heating or cooling coils and other air-conditioning equip ment in the system to protect them from dust. The char acter of the dust arrested by the filters in aa air-intake duct is likely to be mostly particulate matter of a greasy nature, while lint may predominate' in dust from within the building. The published performance data for all air filters are based on straight-through unrestricted air flow. Filters should be installed so that the face area is at right angles to the air flow whenever possible. Eddy currents and dead air spaces should be avoided, and air should be distributed uniformly over the entire filter surface, using baffles or diffusers if necessary. Failure of air-filter installations to give satisfactory re sults can, in most cases, be traced to faulty installation or improper maintenance or both. '. The most important requirements of a satisfactory and efficiently operating air filter installation are: 1. The filter must be of ample size for the amount of air it is expected to handle. An overload of 10 to 15 percent is regarded as the maximum allowable. When air volume is subject to'iacrease, a larger filter should be installed. 2. The filter must be suited to the operating conditions, such os degree of air cleanliness required, amount of dust in the entering air, type of duty, allowable pressure drop, operating temperatures, and maintenance facilities. 3. The filter type should be the most economical for the specific application. The first cost of the installation should be balanced against efficiency and depreciation as well as expense and convenience of maintenance. The following recommendations apply to filters installed with central fan systems: 1. Duct connections to and from the filter should change size or shape gradually to insure even air distribution over the entire filter area. 2. Sufficient space should be provided, in front as well as behind the filter to make it accessible'for inspection and service. A distance of two feet may be regarded as the mini mum. 3. Access doors of convenient size should be provided in the sheet-metal connections leading to and from the filters. 4. All doors on the clean-air side should be lined with felt to prevent infiltration of unclean air. All connections and seams of the sheet-metal ducts on the clean-air side should be as air tight as possible. 5. Electric lights should be installed in the chamber in front of and behind the air filter. 6. Filters installed close to an air inlet should be protected from the weather by suitable louvers, in front of which a large mesh wire screen should be provided. 7. Filters, other than electronic air cleaners, should have permanent indicators to give a warning when the filter resist ance reaches too high a value. - Safety Requirements An investigation of safety ordinances should be made by the engineer when the installation of an air cleaner of any considerable size is contemplated. It is possible that combustible filtering media may not be permitted in ac cordance with some existing local regulations. Combus tion of dust and lint on a filtering medium is possible, though the medium itself may not burn. ADSORPTION OF VAPORS OTHER THAN WATER Many of the foreign gases in the atmosphere are selec tively adsorbed by charcoal. Included are many of the organic gases, such as those emanating from animals and people, some of the gaseous constituents of combustion, alcohols, ketones, esters, and gaseous products of putrefac tion. Charcoals differ widely in their adsorptive capacity. Those which have marked adsorption characteristics, such as properly prepared coconut shell charcoals, are sometimes called activated charcoals or activated carbon* These ma terials can adsorb approximately 50 percent of their own weight of many organic gases at 70 F. The charcoal may be used for a long time by reactivation at high temperatures, under which condition it gives up the adsorbed gases. Temperatures of approximately 1000 F are desirable for reactivation. Charcoals for use in air handling systems should be able to stand physical handling, including re activation, without excessive loss by breakage or dusting. As applied in air handling systems, the charcoal is placed in perforated metal containers which are grouped in frames and set in the air stream. The percentage removal of an or ganic gas, such as carbon tetrachloride, is 95 percent or above, when placed in intimate contact with the carbon at 70 F. In commercial apparatus there may be a bypass ef fect which depends on the physical arrangement of the charcoal containers. This bypassing reduces the percentage removed in the total gas passing through the adsorber. Resistance to air flow is usually selected within the general range of resistance of impingement filters. ' The required quantity of recirculated air to be treated i * i i i 1 | h f Air Cleaning 329 is determined by dividing the requirements for contaminantfree air minus the outdoor sir, by the fraction denoting the percentage removal of the gas in question in the adsorber bank which is to be used. Adsorbers may be applied to reduce objectionable gases entering through the outdoor air inlet. They may also be used to reduce the odors caused by exhausts from process ing. Adsorber beds, in all cases, should be protected from dust, free oil, and grease. PART II--INDUSTRIAL AIR AND GAS CLEANERS Industrial development and growth of industrial areas have had a cumulative effect upon the problem of con trolling contaminants. Not only has the atmosphere in many cities become more polluted, but the intensity of pollu tion at the points of control has increased. Accompanying this increase in pollution there has been a growing consciousness of the need for more effective air cleaning among house wives, store managers, industrialists, and legal inspectors, and this has resulted in increasing severity of regulations pertaining to collection of dust and contaminants. Air cleaning for the supply system is usually accomplished by means of some type of air filter. To prevent escape of industrial dust into the atmosphere, some type of collector is required. An industrial air-cleaning installation is de signed to perform one or more of the following 6 functions: 1. Prevent a nuisance or physical damage to an individual, a plant, or adjacent property. 2. Prevent re-entry of contaminants to working spaces. 3. Reclaim usable material. 4. Reduce fire, explosion, or other hazards. 5. Permit recirculation of cleaned air to working spaces. 6. Allow utilisation of cleaned gases for processes. DEGREE OF AIR CLEANING REQUIRED The amount of material which can be discharged-to the atmosphere is established by local or state regulations prepared by pollution control, labor, or health departments. Standards are established to prevent injury to persons or property. The need for control within the plant is often of prime interest to the industrialist for protecting his equipment, improving his product, and providing a clean working environment. The re-entry of contaminants to working spaces is prevented by effective air-cleaning devices since only a clean effluent'"is discharged to the ambient atmosphere.. Public nuisance complaints often occur even when the effluent concentration discharged to the atmos phere is below the permissible limits of concentration and visibility. Plant location, contaminants involved, and me teorological condition of the areas must be evaluated in addition to existing regulations or codes of good practice. Eire and explosion hazards are created by combustible dusts, vapors, or gases. Safety may be affected by loss of visibility, settlement, or accumulation of various materials. The cleaning device can prevent these hazards by provid ing an effluent below the inflammation limit, visibility index, and point where settlement or accumulation will occur. The degree of air cleaning for the recovery of usable material is a matter of economic evaluation which will vary with such factors as quantity and value of material collected, capital cost, and operating cost. Air cleanliness must be of the highest order where toxic materials are involved and the cleaned air is recirculated to the workroom. Such recirculation is. considered poor practice and isprohibited by many regulations where toxic materials are involved, except for those cases where dis charge to atmosphere is impossible or decidely impractic able. Where air is recirculated, its contamination must not exceed the established maximum allowable concentrations listed in Chapter 7. Usual requirements are a fraction, often Ys to Vi, of this standard, depending on: regulation involved, air quantities recirculated in relation to the cubical con tent of working space, and the presence of other exhaust systems discharging to the atmosphere. Cleaning requirements for the utilization of cleaned gases are dependent on the process and are generally of the highest order (usually comparable to atmospheric air cleanliness). Regardless of standards it is good practice to install the most effective collection equipment available in the light of practical operation features, installation, and equipment costs. This is warranted because the required degree of cleaning is increasing continually. FACTORS AFFECTING SELECTION Selection of an industrial air cleaner for a given applica tion requires an evaluation of the following 5 considerations: 1. Concentration, particle size, and size distribution of the contaminant. . 2. Degree of cleaning required. 3. Conditions of air or gas stream with reference to tempera ture, moisture content, and chemical composition. 4. Characteristics of the contaminant, corrosiveness, solu bility. adhesion, or packing, and its specific gravity, surface, and shape. . 5. Methods of disposal or salvage that meet the conditions imposed by material, process, or plant location. In view of the range of these variables, all available test data, application experience, and manufacturers' perform ance data should be considered, TYPES AND APPLICATION There are a number of principles involved in the opera tion of industrial air and gas cleaners. They are illustrated by the following types of cleaners: - 1. Inertial Separators (Gravitational or inertial force prin ciple): Baffle Chambers, Centrifugal Collectors. 2. Scrubbers and other Wet Collectors: Air Washers, Wet Filters or Packed Towers, Spray Towers, Centrifugal or Iner tial Scrubbers, Venturi Scrubbers. 3. Filters: Fabric Filters, Ultra or Absolute Filters. 4. Electrostatic Precipitators. 5. Adsorbers, Absorbers, and Combustion Devices. Units employing these principles may apply them singly or in combination. The important characteristics of any unit are: its collection efficiency, resistance to air or gas flow (power requirements), ability to maintain specified , air or gas flow during its operating cycle, and maintenance ^ requirements. ' . In relation to industrial air cleaners, efficiency of collec tion is generally presented on a basis of weight removal. In many instances, collection efficiency is expressed in terms of weight removal in specific particle size ranges. Occasion ally efficiencies are given in terms of visibility or photo metric evaluation. Under other circumstances efficiencies are stated by particle- count. For most process recovery problems and air pollution control, the weight basis has been adequate. When loss of visibility is the major problem, light opacity measurements may be required. 330 CHAPTER 24 1959 Guide Prom a hygienic viewpoint where air is to be recirculated, only the contaminant concentration in the recirculated air stream, rather than the collection efficiency, should be con sidered. Correlation between the various efficiencies is poor due to the wide variation in particle size, size distribution, and shape. Resistance or pressure drop through any given collector is related to the operating principle, and varies about as follows: low resistance collectors--up to 2 in. water; me dium resistance collectors--2 to 8 in. water; high resistance collectors--8 to 25 in. water. In mechanical centrifugal collectors of the wet or dry type (power driven impellers or rotors) resistance alone is not of significance since these devices are also air movers and therefore the factor of paramount importance is the overall power consumption of the unit. This is also true of certain types of wet collectors which require auxiliary pimping power. The ability of any unit to maintain specified air or gas flow during its operating cycle is also a function of its operating principle. For example, inertial collectors of the ample and centrifugal type are able to maintain constant resistance regardless of concentration and particle size. How ever, adhesive materials may collect at the entry, through out the unit, and at the exit, and thus cause a reduction in air flow and serious maintenance problems. With the ex ception of packed towers and wet filters, wet collectors operate at constant resistance throughout their operating cycles. However they may also be adversely affected by adhesive or corrosive materials. Wet filters or packed towers will eventually become clogged because of retention of inert dusts. Units employing fabric or other filter media .will have resistance influenced by the concentration, particle size, shape, and packing characteristics of the aerosol. Their overall resistance during the operating cycle may increase gradually over a known or determined period. Auxiliary cleaning devices such as separate compartments, alternately shaken, reverse air flow, or reverse jet air flow may main tain constant or nearly constant resistance or insure only small fluctuations in air or gas flow. Electrostatic' pre cipitators have the outstanding characteristic of maintain ing a constant air flow with an accompanying low resist ance. Adsorbers behave similarly to packed towers in that they provide constant resistance until the voids become seriously plugged with inert dusts. This generally requires a matter of several months on normal applications. It has been found that inertial separators require the least maintenance. Simple wet collectors rank next in this respect. Complex wet collectors and fabric arrestors require maintenance on a definitely scheduled basis. Electrostatic precipitators require the usual maintenance connected with high-voltage equipment and may vary widely. The main tenance of adsorber type units is minimal and is based primarily on the amount of inert material encountered. INERTIAL SEPARATORS There are many types in this group. These range from simple settling chambers utilizing gravitational forces, to complex centrifugal devices using abrupt directional changes or motor driven rotors. They all have the desirable features of constant resistance during their operating cycle and do not require any special construction for temperatures under 750 F. Usually they require less maintenance .than other types of collectors. . Table 1 .... Inertial Separator Characteristics Kind Efficiency Partido Sign' Conge In Microns >100 00-10 <10 R#*mfence (Proscur* Drop) Description and Remarks Settling Meand baffle cham bers JOW uOW Low A large chamber to re duce velocity to permit settling. Auxiliary baf fles are sometimes used to improve perform ance. Requires large space. Large diame ter cy clones High Me Low dium to low Low Considered as single body over 3 ft in diam eter. . Gases and material must be dry. Air-tight dust bins or continuous re moval of material must be provided. Space re quirements moderate. Refined design cen trifu gals Sigh High Me Me dium dium to low Available as multiple small-diameter tubes, scroll-shaped bodies, and multiple louvers. Gases and material must be dry. Air-tight dust bins or continuous re moval of material must be provided. Space requiremeata moderate. Integral High rotor type High Me See re Rotor acts as air mover dium marks and separating element. to Usually limited' to dry low granular materials and dry gases. Low space requirements. No external pressure loss involved but power requirements are higher than usual exhauster. Slotted scroll fan High Me Low dium to low See re Separation takes place in marks in fan scroll. ' No external loss involved but power requirements are higher than usual exhauster. On.the basis of their important characteristics inertial separators may be classified according to Table 1. SCRUBBERS AND OTHER WET COLLECTORS In these collectors many methods are used to wet the contaminant and remove it from the air stream. A number of wet collectors are similar in design to dry collectors with the addition of sprays or liquid contactors. The mech anism of separation in wet collectors depends on inertial Air Cleaning 331 Kind Air washers Wet filters Packed towers Spray towers Centrifugal or inertial scrubbers Venturi scrubber Table 2 .... Characteristics of Wet Collectors Efficiency Pcrtiri* drn rang* i ' microns . >10 10-1 <1 Reririonc* In. Wafer Wafer Rafe In Gallons Par 1000 Co Ft Go* Mainten ance Description and ttaaarks High Medium Low Low (lea: 5-15 than 1 ' Medium Composed of one or more banks of low-pressure sprays and flooded eliminator plates. Space requirements are large. Water is usually recirculated. High High Medium Low (less 3-8 than i; Medium Composed of one or more banks of low-pressure sprays flooding packed cells of glass or other fibers. Space requirements are large. Limited to low loadings of solid particles. High High Medium High 5-10 High Composed of granular or ceramic packing. Space requirements large. Generally limited to gas absorption. High Medium Low Low 5-10 Low Usually a vertical chamber equipped with lowpressure water sprays at the top or along the walls. Baffle plates may be provided for contacting. Space requirements medium. Usually applied for hot gases. High High Medium to high Medium (see re marks) H 40 See re marks This classification includes most of the com mercial wet collectors. They may. utilize singly or io combination, low- or high-pres sure sprays, wetted plates, rotating mem bers, liquid gas contact by induction or cen trifugal action. Some of these units (disintegrators) have high overall power requirements for driving the rotor while others have high power con sumption for raising water pressures for spray noszles. Maintenance varies from low to high depend ing on component parts. Simple gas liquid contact units would be classified as low. Units having rotating members may vary from medium to high depending on the type of service. . High High High High 5-10 (12-25) Medium Consists of a simple venturi with low-pressure sprays at throat followed by a cyclonic type separator. Space requirements are low. Unit functions independent of grain loadings. High velocity at venturi throat may cause erosion problems. forces such as impaction and impingement, and in some cases, diffusion: Wet collectors do not require any special construction for high temperatures. They are suitable for use on mixed contaminants such as gases and solid or liquid particles. The collection of dust in . a wetted form eliminates a sec ondary dust problem in disposal of collected material. Protection against corrosion and freezing may be necessary and disposal of waste liquids may become a problem. With the exception of the packed towers and wetted filters they all have a constant resistance during their operation. On the basis of their important characteristics wet col lectors may be classified according to Table 2. FILTERS Filters for industrial air and gas cleaning consist pri marily of cloth dust collectors and the ultra or absolute type of filter. Cloth dust collectors are generally constructed in the form of housings with cloth envelopes drawn over wire screen frames or with vertical cloth bags or tubes. Cloth filters depend to a great extent on the accumulated dust 1 I 1 332 CHAPTER 24 1959 Guide Table 3____ Characteristics of Fabric filters efnciencj' Kind Parlidm dzm rang* m njcraai Heat- filtering Velocity (Maintenance tanoo >10 10 to 1 <1 Cloth collector High (shaken or rapped)* High Mod erate to high Me dium 1-6 Medium to high (peri odic) Cloth collect High ors (reverse air or jet cleaning)* High Mod erate to high Me dium to high 10-35 Medium to low Absolute type* High High High Me 3-14 None (seo dium remarks)* * Space requirement* larso- Requires scheduled cleaning. b space requirements medium- Cleaning constant during operating eyde. Added horsepower used <or reverse jet action. Space requirements smell. Requires replacement of . unit when predeter- mined rretstODce b attained. Ordinary cleaning not possible. layer for their effectiveness. Their basic or initial efficiency depends upon the type of fabric employed; felted media such as wool gives higher initial removal than woven fabrics. The increase in resistance to air flow, resulting from the accumulated dust layer, is related to rate of flow, con centration, and characteristics of the contaminant. Re moval of the collected material is accomplished through periodic shaking by single mechanisms or combinations of them employing rapping, or through reversal of air flow, or by TTieans of high-velocity reverse air jets. With shaking or rapping, air flow is not constant and filtering velocities are usually held under 6 fpm. With reverse jets or reverse air flow, substantially constant air flow is maintained and filtering velocities are generally higher (up to 35 fpm). Filtering velocities in all fabric collectors are highly de pendent upon the aerosol, fume, or dust being collected. The ultra or absolute type of filter" may consist of pleated cellulose asbestos paper,' deep sand beds, composite glass wool layers, compressed glass fiber in the form of paper, or batts and resin wool. The use of this type of filter is limits to concentrations in the range of outdoor air where very high efficiencies, greater than 99.95 percent are required. Fabric filters are not suitable for high temperatures, above 300 F, acid mists or vapors, or mixed contaminants such as wet corrosive gases and solid or liquid particles. Cotton fabrics are limited to 180 F, whereas wool is limited to temperatures under 200 F. A wide variety of natural and synthetic filter media are available for various temperature and corrosion conditions but caution must be exercised relative to rupture, high temperatures, and corrosive gases. When properly selected, efficiencies are often high enough to permit recirculation of air except, possibly, when han dling toxic contaminants. On the basis of their important characteristics, fabric filters may be classified according to Table 3. RECTROSTATIC PRECIPITATORS Electrostatic precipitators for industrial air and gas clean ing differ materially from the low-voltage designs described in Part I of this chapter, although the principles of opera tion are similar For industrial concentrations, it is obvious that, more severe demands are made upon methods of .cieaniug the collector, disposal of collected materia!, and servicing practices. Low-voltage cleaners for industrial loadings to date do not have sufficient inherent dust-holding capacity. One exception in the field of exhaust systems is that of the oil-mist collector, which functions satisfactorily on a liquid aerosol with the conventional low-voltage type (2 stage) electrostatic precipitator. Industrial precipitators employ an assembly of parallel collector electrodes of various constructions, including cor rugated plate, rod curtains, or perforated plate. Air flow is usually horizontal, although special construction may permit vertical air flow. Higb-voltage collectors were, made in the form of vertical pipes, and are used for high oper ating pressures and for wet-collector designs where water continuously flows downward inside the pipe walls of the collector electrode. The,negative discharge electrodes or rods are accurately centered between the usual 9 in. col lector electrode spacing, the latter being of positive charge. Precipitation occurs in a single stage wherein ionization and collection are carried on simultaneously throughout the unit, and depend on high potentials of 25,000 to 75,000 volts. The high-voltage direct current is supplied by either mechanicAl or electronic rectifiers. High efficiencies are obtained by allowing suitable time for contact in the collector zone, and by proper ratio of air flow velocity to that of transverse velocity of the negatively charged particles toward the positively charged collector plates. ' . Air velocities vary from 240 fpm to 480 fpm with a constant pressure drop of I****8 than Vt in. water. Since the maximum efficiency is obtained with the finer particles at low concentrations, and the precipitation is not effective for large particles, inertial separators are frequently used in series with these units. Attention should be directed to the prohibition of air recirculation to occupied spaces. High-voltage -cleaning equipment produces ozone and nitrogen oxides in excessive quantities. The major source of maintenance usually will be in conjunction with the high-voltage rectifying equip ment rather than the collector. Although usually used for elevated temperature work, unless the gases are precon ditioned, temperatures in excess of 700 F should be avoided. Collector electrode cleaning is accomplished by a rapping device, either electrical or pneumatic, without interrupting operation. The dry plate surfaces release the dust into hoppers below the plates. Some wet cleaning methods are also used. .' Electronic precipitators require large spaces, maintenance may vary widely, and initial costs are high. Efficiency is a function of the aerosol encountered and usually ranges above 90 percent. ' ABSORBERS, ADSORBERS, AND . COMBUSTION DEVICES One of the important problems in industrial air and gas cleaning is the removal of soluble, insoluble, or combustible gases and vapors from fluid streams before their discharge to the atmosphere. These contaminants may create prob lems which are distinct from the particulate removal dis cussed previously; It has been pointed out that scrubbers and other wet collectors may remove gases and particulate matter from contaminated air streams. However, the units Air Cleaning 333 described are intended primarily for particulate removal or heat. Resistance depends upon the adsorbent mesh size, with the exception of the spray or packed towers or wet depth, and velocity. It may range from less than one inch cell devices. Absorption devices are intended primarily for the re of water to several inches of mercury. Adsorbent beds are usually limited, because of their cost, moval of readily soluble gases which can be removed by to applications where recovery may be economically fea simple absorbing agents such as water or alkali; for ex sible. Removal of particulate matter by use of precleaners ample, the removal of hydrochloric acid gas by a caustic is necessary if significant loadings are involved as the ad spray. Adsorption apparatus is intended primarily for removal sorbent voids are readily plugged. They are not suitable for high temperature conditions. Silica gel and alumina ex of organic vapors in either high concentration (solvent re - hibit a strong preference for water vapor whereas charcoal covery) or low concentration (odor removal). The first does not. process is usually carried on as a matter of economic re covery. In the second process, the concentration of the Combustion Devices contaminant .must be low enough so that the adsorbent will This group of industrial air cleaners entails the use of have a reasonable life before replacement or reactivation. high temperatures or catalysis combined with some eleva Combustion, either total or catalytic, may be used to tion in temperature to destory or decompose organic and destroy organic compounds, either gaseous or particulate, some inorganic gases which create obnoxious odors. The - which create odor problems. The use of catalysts to reduce devices are divided into those in which combustion is ob the temperature needed for combustion is comparatively tained by use of liquid or gaseous fuels and the secondary recent in this field. In some instances the heat of combus air for combustion is provided by the contaminated air. tion may be recovered for utilization. The temperature In essence, the simplest form involves passing the con necessary for destruction of compounds varies with the taminated air through the combustion chamber of a boiler nature of the contaminant. However, partial combustion - or fire box. Special fire boxes or brick checkerwork may may alter the compound to render it innocuous. The tem also be employed. Catalytic devices consist of noble metal perature required for complete destruction is usually above packed into frames in the form of ribbons or- screens or 1100 F. Catalysts may only require heating to 500 F or may be ceramic granules coated with noble metal catalysts. may operate without heating if the gas temperature is above The frames or packing are placed in a housing over which 500 F. ' ' . the gas stream to be decontaminated is passed. The con Absorbers taminants break down and are reduced to elemental gases of an innocuous nature. Catalysts reduce the amount of These may consist of spray chambers, packed towers, heat necessary but may become contaminated by-sulfur or or wet-cell washers through which an absorbing agent is other elements. recirculated. The gases collected may be converted to in The performance of a combustion device is dependent soluble salts or usable acids and other compounds. The upon the retention period of the contaminant in the high performance of these devices depends upon several factors temperature zone. Removal or destruction is thus dependent such as the solubility of the gas, its vapor pressure, its ' on velocity and surface area of the heat-transfer device. rate of reaction with the absorbent, the velocity through If properly designed, obnoxious odors are removed. the collector, and area of the absorbing surface either as The resistance of the direct combustion unit is negligible spray droplets or wetted media. These are generally de since it is an integral part of the fuel-combustion system. signed for the specific purpose intended. They usually are intended to collect over 95 percent of the contaminant. Catalytic devices behave in a manner comparable to packed beds or filters except that they are not plugged by organic Resistance depends upon the particular design and ranges particulates but may be affected by inorganic solids. from 1 to 10 in. of water in most installations. Their Maintenance of these types of units is essentially de resistance during their operating interval is constant unless pendent upon the contaminants encountered. The direct- serious plugging of packing occurs. Spray units are seldom combustion system requires little care other than that affected by plugging. Packed'abeorption devices require a required by ordinary fuel-burning equipment. Catalytic precleaner to remove particulates if long trouble-free serv ice is desired. Maintenance of spray nozzles is a function units become contaminated slowly and will require removal for reactivation at certain intervals depending upon the of the degree of atomization used and of conditions encoun application. tered, such as purity of spray liquids. . Economic factors may limit the use of direct-combustion Protection against corrosion and freezing may be neces- methods unless there is a demand for the heat generated. sary and disposal of waste liquids may create secondary problems. They may best be applied to processes employing com bustion. Catalytic units require temperatures of at least Adsorbers 500 F and consequently it may be necessary to preheat the contaminated air to this value. These units consist of a chamber filled with a granular adsorbent. The adsorbent may be activated charcoal, rilica REFERENCES gel, alumina, and other treated solids. Activated charcoal is the most common and has the highest retention per unit weight for organic solvents. Performance of adsorbent beds 1 S. S. Leopold and C. S- Leopold: Bronchial asthma and allied allergic disorders {Journal of the American Medical Asso ciation, March 7, 1925, p. 731). depends upon their thickness, velocity of the gas passing, mesh size (surface area) of adsorbent, and temperature of the vapor being removed. They can be designed to obtain almost complete removal of organic vapors and some in organic gases. They may be reactivated by the use of steam * L. H. Criep, M.D., and M. A. Green, M.D.: Air cleaning as an aid in the treatment of hay fever and bronchial asthma {Journal of Allergy, January 1936, p. 120). * O- M. Lidwell: The bacterial filtration efficiency of an elec trostatic air cleaner {Journal of the Institution of Heating and Ventilating Engineers, London, June 1951, p. 139). if 334 CHAPTER 24 1959 Guide 4 R. A. Nielsen: Dirt pattern on walls (ASHVE Transac tions, Vol. 46, 1941, p- 247). * P. Drinker and T. Hatch: Industrial Dust (McGraw-Hill Co., New York). * Cods for Testing Air Cleaning Devices Used in General Ventilation, Section I, Unit or Panel Type Air Filtering De vices (Air Filter Institute, 1953). T ASffVB Standard Cods for Testing and Rating Air Cleaning Devices Used in General Ventilation Work (ASHVE ThaNsactions, Vol. 39, 1933, p- 225). * R S. Dill: A test method for air filters (ASHVE Transac tions, Vol. 44,1938, p. 379). H L- Barnebey: Activated charcoal for air purification (ASHAE Journal Section, Heating, Piping and Air Condi tioning, March 1958, p. 153). * Laboratory Design for Handling Radioactive Materials (Building Research Advisory Board, National Research Coun cil, Washington, D. C., Research Conference Report, 1952). BIBLIOGRAPHY H. C. Murphy: Design and application of oil-coated air filters (ASHVE Transactions, Vol. 33, 1927, p. 73). W. G. Frank: Operation and maintenance of air filters (Heat ing, Piping and Air Conditioning, May 1931, p. 378). . W. G. Frank: Sire and characteristics of air borne impurities (Heating, Piping and Air Conditioning, January 1932, p. 35). O Weehsberg: Fundamental principles in the design of dry air filters (ASHVE Journal Section, Heating, Piping and Atr Conditioning, April 1933, p. 217). . H. E. Ziel anl Henry Sleik: The economic factors inconvert ing recirculated air for ventilation (ASHVE Journal Section, Heating, Piping and Air Conditioning, July 1943, p. 367). F. B. Rowley and R. C. Jordan: ASHVE Research Report No. 1094--Air filter performance as affected by kind of dust, rate of dust feed, and air velocity through filter (ASHVE Transactions, Vol. 44, 1938, p. 415). . ' F. B. Rowley and R- C. Jordan: ASHVE Research Report No. 1122--Air filter performance as affected by _low rate of dust feed, various types of carbon, and dust particle sise and density (ASHVE Transactions, Vol. 45,1939, p. 339). F. B. Rowley and R. C. Jordan: ASHVE Research REf-oirr No. 1145---The effect of lint on air filter performance (ASHVE Transactions, Vol. 46, 1940, p. 25). F. B. Rowley and R. C. Jordan: ASHVE Research Report No. 11--Comparison of the weight, particle count and dis coloration methods of testing air filters (ASHVE Transac tions, Vol. 47, 1941, p. 29). F. B. Rowley and R. C. Jordan: ASHVE Research Report No. 1187--Economical air velocities for mechanical air filtra tion (ASHVE Transactions, Vol. 47, 1941, p. 391). F. B. RowleyandR. C. Jordan: ASHVE Research Report No. 1218--Overloading of viscous air filters during accelerated tests (ASHVE Transactions, Vol. 48, 1942, p. 437). G. W. Penney: A new electrostatic precipitator (Electrical Engineering, January 1937, p. 159). H. E. Corbitt and N. J. Clark: Electrostatic precipitation for aircraft (Aero Digest, December 1940, p. 132). C. E. Miller: Pointers on selecting equipment for industrial gas cleaning (Chemical and Metallurgical Engineering, March 1938, p. 132). ' W. A. Schmidt and E. Anderson: Electrical precipitation (Electrical Engineering, August 1938, p- 332). A. W. Simon and L. C. Kron: Electrical precipitation (Elec trical Engineering, February 1932, p. 93). E. Anderson: Some factors and principles involved in the separation and collection of dust, mist, and fume from gases (American Institute of Chemical Engineers Transactions, Vol. R. B. Rathbun: Electrical precipitation of solids from smelter gases (American Institute of Electrical Engineers Trans actions, Vol. 41, 1922, p. 815). ' A. C. Stern, J. Baliff. A. E. Perina, R. Crowley, B. Feiner, and A. A. Urbano: Characteristics of unit dust collectors (ASHVE Transactions, Vol. 52, 1946, p. 237). J. M. Kane: Operation, application and effectiveness of dust collection equipment (Reference Section, Heating and Ventilat ing, August 1952). ' C. A. Dapple: Chapter 9 (Air Pollution Abatement Manual, Manufacturing Chemists Association). - S. K. Friedlander, L. Silverman, P. Drinker, and M. W. First: Handbook on Air Cleaning (U. S. Atomic Energy Com mission, Washington, D. C-). M. W. First, R. Moschella, L. Silverman, and E. Berly: Per-. fonnance of wet-cell dashers for various aerosols (Industrial and Engineering Chemistry, Vol. 43, 1951, p. 1363). J H. Perry: Chemical Engineers Handbook (McGraw-Hill Co-, New York, I960, 3rd ed.). American Industrial Hygiene Association Quarterly, March 1950. .... R. J. Ruff: Design factors in catalytic fume elimination (Heating and Ventilating, September 1953, p. 84). A. Nutting and R. F. Logsdon: New air filter code'(Heattny, Piping and Atr Conditioning, June 1953, p. 77). CHAPTER 25 SOUND CONTROL Acoustical Terminology; Apparatus for Measuring Sound; Approaches to the General Problem of Noise Control; Criteria for Noise Control; Kinds of Noise; Noise Generated by Fans, Grilles, and other Sources; Sound Attenuation in Ducts; Determination of Room Levels; Cross Transmission between Rooms and through Dud Waff* Cortfro/Zing Vibration from Machine Mountings . THE NOISE created by heating, ventilating, and air conditioning equipment has become an important factor in modern building design. Related to this, and of equal im M -- 10 logia -- decibels I* (2) portance, is the problem of the transmission of speech or music from one part of the building to another through venti lating and air-conditioning ducts. The architect and the acous Alternatively, the ratio of two sound pressures squared is expressed in the same units, tical engineer cooperate to produce rooms that are satisfactory for speech, music, or other intended uses. The ventilation and M TM 10 log* -- 20 log* -- decibels Pr pi (3) acoustical engineers cooperate to ventilate and air condition these rooms to be physically comfortable without adding noise in excess of established requirements. This chapter is planned to supply part of the information needed to achieve adequate quietness in rooms that are ventilated and air conditioned - through supply ducts. The quieting of unit heaters and coolers These relations tacitly ft-ooim* that: W = p*/Z, which means that Z, the acoustic impedance, is real, and that for Pi and pt, Zi -- Zt. This is not usually the case, but because sound pressure is the easiest variable to measure in a sound field, the relation: is assumed to be the job of the manufacturers and is not covered here. Remaining information on cost, availability, durability, and ease of installation can come only through M = 20 log* -- decibels P* (4) experience with practical msta]la.tinn is commonly used. Thus, in a sense when used in this way, the ACOUSTICAL TERMINOLOGY1 Sound Power W is the power in watts produced by a source of sound. This power may be (a) the total power radiated by the source over its entire frequency range, (6) the power radiated in a limited frequency range, or (c) the power radiated in each of a series of contiguous frequency bands. The fre decibel is redefined on the baas of a pressure squared ratio rather than a power ratio. - Octave Frequency Bands. The frequency range of a noise is frequently broken up into octave frequency bands where, in principle, the upper frequency is twice the lower frequency of the band as shown in the following table. quency range or frequency band should be clearly stated. . Sound Intensity I is the power radiated in a specified direc tion through unit area normalto this direction, e.g., watts Band Number Urnof Frequent.; Limits Approximate CoowaWe * Mean Frequency per square meter, watts per square foot, or watts per square centimeter. Sound Pressure p is the root-mean-square incremental pressure produced when a sound wave passes through an otherwise undisturbed medium. The unit is the microbar (l dyne per sq cm or 0.1 newton per sq m). Frequency f is the rate of repetition of a periodic phenome non. The frequency is the reciprocal of the period, or the time necessary for the phenomenon to repeat. The frequency / of 1 20 to -75 cps* 40 2 75 to 150 105 3 160 to 300 210 4 300 to 600 425 5 600 to 1200 - 850 6 1200 to 2400 1700 7 2400 to 4800 3400 8 4800 to 10,000* 6900 a single tone sound wave is equal to the ratio of the speed of * The highest end lowest a* used, somewhat more sound c to the wavelength X of the tone. / cfh, or c /X. oae oeteve aj indicated The unit is the cycle per second, or cps. Decibel db is a dimensionless unit for expressing the ratio of two numerical values (usually electrical or mpchanifftl power) on a logarithmic scale. The number of decibels is ten - Sound Power Level PWL is ten tirm>s the logarithm to the base 10 of the ratio of the sound power to the reference power of l0-u watt. Thus, Power Level in the English system? tunes the logarithm to the base 10 of the numerical ratio of the two quantities. For example, let HVand TV, designate PWL - 10 log dbe (5) two powers; or / and /* designate two sound intensities, let M designate the number of corresponding decibels, then where : M 10 log* decibels (1) 335 W -- sound power, watts. The unit is the dbc. Th^ symbol dbe means that the sound 336 CHAPTER 25 1959 Guide power level is convenient to use in the English system and that 10-u watt is the reference power. Sound Intensity Level {Li) is ten times the logarithm to the base ten of the ratio of the sound intensity I to the reference intensity of 10~" watt per sq cm (or it equivalent of I pico- watt per sq m). Thus Li - lOlogu^dbi (6) I -- watts per square centimeter or (7) 1 = watts per square meter. The unit is the (fin. Either formula gives the same result. Sound Pressure Level Lp is twenty times the logarithm to the base 10 of the ratio of the sound pressure p to the reference sound pressure of 0.0002 microbar, i.e.. where . Lp ^ = 20 login 0.-0002 dbc (8) p TM sound pressure, microbars (dynes per square centimeter). - The unit is the dbc, where c stands for the C scale or flat scale on the sound level meter. Loudness N is the intensive subjective attribute of an audi tory sensation, in terms of which sounds may be ordered on a scale extending from soft to loud. The unit is the sone. The number of sones is directly proportional to the loudness. By definition, a 1000 cps pure tone with a sound pressure level of 40 dbc has a loudness of 1.0 sone. Loudness Level (Ly) of a sound is numerically equal to the sound pressure level Lp of a simple tone of frequency 1000 cps that is judged by the listeners to be equivalent in loud ness. The unit is the phon. In this text, for a 1000 cps tone, L* inphona is assumed to be related to N in sones by the for mula ' =* 33 log,tt N + 40 phons (9) This approximation is assumed valid* tor N > 1. Sound Level at a point in a sound field is the reading in deci bels of a sound level meter constructed and operated in ac cordance with the latest edition of American Standard Sound Level Meters for the Measurement of Noise and Other Sounds.* The reading is taken with the proper weighting network switched into the circuit. The unit is dba, if the reading is taken on the A scale; dbb if taken on the B scale, and dbc if taken on the C or flat scale. The use of these scales is dis-. cussed later. - Attenuation is ten times the logarithm to the base 10 of the ratio of the sound intensities at any two points along any continuous acoustic path in the direction away from the source. The unit is the decibel. For a signal confined to a chan nel or duct, the intensity values are averaged over the cross section. -. Transmission Loss TL is ten times the logarithm to the base 10 of the sound energy incident on an obstruction in an acoustic path to the sound energy that is transmitted through the obstruction. The unit is the decibel. Noise Reduction NR is the difference in decibels of the sound pressure levels at two points along an acoustic path in the direction away from the source; alternatively, it is the dif ference in decibels of the sound pressure levels existing at a single point before and after the addition of acoustic treat ment to the path. APPARATUS FOR MEASURING SOUND The measurement of sound or noise is usually accomplished by means of (a) a sound level meter SLM consisting of a micro phone, an amplifier, a variable attenuator, weighting net works, and an indicating meter which reads directly in de cibels, and (6) an octave band analyzer OBA which is a set of filters tor determining the sound pressure level of the sound being measured in each of eight octave-frequency bands. The approved sound level meter and octave band analyzer should comply with the specifications in the latest version of the American Standard Sound Lead Meters for Measurement of Noise and Other Sounds, Z24.3-1944, and American Standard Specifications for cm Octave-Band filter Set for the Analysis of Noise and Other Sounds, Z24.KM953, published by the Ameri can Standards Association. The SLM is designed to indicate either the sound pressure level Lp or the sound level (if weighting networks are used) above the standard reference level of 0.0002 microbar. The SLM itself has three weighting networks, which,are approxi mations to the equal loudness contours for pure tone sounds of three discrete loudness levels. The equal loydness contours give the Lp of a 1000 cps pure tone that sounds equally as loud to the average listener as the tone whose loudness level is desired.1 Unfortunately, standard sound level meters do not give an indication of the loudness of more complex noises. To serve es a basis lordetermining the loudness of more complex noises, measurements of complex sounds are taken on the flat scale (C scale) of the SLM using the OBA to determine the dis tribution of the sound pressure level as a function of. fre quency. Computations of loudness and loudness level .are made from these data. , Allowable deviations in response and acceptable tolerances recognized in the standard for the sound level meter are: 0.5 db at 80 cps to 630 cps; +2.0, --2.5 db at 25 cps; +2.5 db at 2000 cps; +6.0 db at 8000 cps. Calibration of the SLM and OBA should preferably be made before, during, and after each use by a calibrated loudspeaker.1 In turn, the loudspeaker should be calibrate*} at the factory at frequent intervals. Instructions and precautions in the use of sound level meters are given in Reference 2. APPROACHES TO THE GENERAL PROBLEM OF NOISE CONTROL It is usually necessary to think of noise control problems as composed of three parts: (1) the source, (2) the path, (3) the receiver. . It is sometimes possible to reduce the noise at any or al! of these parts. However, in construction design, the engineer is usually able to do something only with the path. The source may be any piece of equipment or person gener ating audible noises. The transmission path may be a path directly through air or may be a path which includes solid structure such as walls, floors, pipes, duct walls, or air within ducts in various combinations. The receiver is usually a per son who might be disturbed by the noise,'-however, the re ceiver might also be a delicate machine or manufacturing process that roust be isolated from vibration. The acoustic output of a source is ideally specified by its ;Sound Control 337 total sound power level and the sound power level in eachof a group of frequency bands, preferably octave frequency bands. Where the source is not confined to a duct or the like, it may Also be necessary to specify the source directivity, i.e., the relative amount of sound radiating in each direction of inter est. In general, the specification of the acoustic output of a source by a single number is not adequate for engineering design of noise control measures. The sound power outputs of fftga and grilles as noise sources are discussed in later sections. Acoustic losses along a path from source to receiver nor mally exist in any building structure. These losses are a func tion of frequency and can be defined adequately when ex pressed as losses in each of eight octave bands. Losses for common structures, and for ducts of various sizes and shapes, as well as for some packaged sound attenuation devices, are published. Some values particularly applicable to ventilating problems are given in a later section. The response of a person as a receiver has been determined under certain conditions. Noise levels which are found ac ceptable to toe average person under specified conditions are Step 6. Determine the existing attenuations in the path, for example, natural duct losses, losses at bends, and reflection losses at the outlet (see the following section on Sound At tenuation in Ducts). Step 7. Determine the net source power, levels by substracting values from Step 6 from Step 5. Step 3. Determine the sound pressure levels in octave bands at a specified listener's position using as basic data the net source power level from tbe duct, the acoustical properties of the room, and the position of the listener as done in Step 2. Step 9. Subtract the criterion levels from the sound pres sure levels at the listener's position (in decibels) as done in Step 4 to obtain the required amount of noise reduction NR in each of the eight octave bands (refer again to note following Step 4). Step 10. Choose an economical means of providing the re quired NR. The noise reduction required usually must be ob tained by treating toe ducts between the source and the re ceiver either by adding an absorbing lining or by inserting a package unit (see Fig. 1) of known attenuation as a function of called noise criteria. Several frequently used noise criteria are summarized in a later section. The noise criteria to be used - must be chosen with regard to the type of activity to be car ried on in the space beingconsidered. Where delicate machines or manufacturing processes are the receiver, special noise criteria must be determined to fit the need. Noise criteria should best be specified as sound pressure levels in octave frequency bands. A good procedure for attacking a noise control problem in a ventilating system will be illustrated by reference to Fig. 1. The sound power level of the fan is expressed in dbe. Sound attenuation in the duct is composed of losses in the unlined fig. 1-------Typical Ventilation System Problem and lined portions of toe duct, losses at the bend, and end re flection fosses. Added attenuation of the fan noise is achieved by adding additional lining to the duct or providing package attenuation units. Noise is also produced,at the grille and is. expressed in dbe. All losses (attenuation) are expressed in decibels. The procedure follows: Step 1. Determine the sound power level of the grille noise either from published data, or from actual measurements, or from approximate data given in the section on Noise Generated by Grilles. - Step 2. Determine the sound pressure levels in octave bands at a specified listener's position due to grille noise alone which is radiated from the end of the duct, using the acoustical prop . erties of the room and the position of the listener (see the fol lowing section on Determination of Room Levels). - frequency. Because noise may be induced by vibration, a con sideration of the fan mounting may be necessary. Also, if the fan room is adjacent to a quiet space, the construction of the fan room walls to provide adequate noise reduction should re quire attention. It is usually good policy to provide slightly more acoustical treatment than is necessary, thus obtaining a safety factor. A safety factor often used is 5 db greater noise reduction than would be indicated by tbe above procedure. Frequently the controlling noise source in a building with a central station system is sound transmission through the walls of the apparatus room or from a duct plenum. Where such a room or plenum is near occupied rooms, the noise transmitted through tbe walls must be determined. The combined sound pressure levels resulting at a listener's position should be com pared with the criteria as done in Step 4 for noise produced by grilles. Step 3. Determine the allowable sound pressure level in oc tave bands (the criterion) at the listener's position either from CRITERIA FOR NOISE CONTROL published standard data (see the following section on Criteria for Noise Control) or from discussioo&with the architect or the Criteria for noise control in building spaces have evolved ultimate User of the room under design. in the United States from several large scale studies and from Step 4. Subtract the criterion levels from the sound pressure the experiences of engineers who have recorded favorable and levels at the listener's position (in decibels) to determine that the levels at least meet the criterion in each octave band. If the grille noise is higher than the criterion in any octave band, unfavorable reactions to known background noises in many types of rooms.* a larger grille site must be used. The acoustical engineer should carefully question the user Note: The total noise in the room is due to both the grille noise and the fan noise. If the grille noise levels just meet the criterion, then the fan noise emitted in the room must be at least 5 db below the criterion- Alternatively, the grille noise of the building to make certain of the kind of uses that he has in mind. For example, a coliseum used for sports onfy, need not be as quiet as a coliseum also used for concerts. As another levels and the fan noise levels in the room could each be 3 db example, a hall for band concerts need not be as quiet as one below the criterion, because when two noises of tbe same in tensity are combined, tbe total level is 3 db higher than either. As a third choice, the fan noise could just meet the criterion, and the grille noise be at least 5 db below the criterion. for chamber music. In fact, some rooms are better if they are not too quiet. It baa been found that libraries, drafting rooms, and study rooms that are too quiet are not so desirable as Step 5. Obtain the sound power level in octave bands of the they would be with moderate noise levels. In very quiet rooms fao, either from published data, or from actual measurements, of these types, sounds such as whispering, turning of pages, or from approximate formulas given in toe following section on Noise Generated by Fans. creaking of the floor, coughing, closing of doors, etc., act to distract the occupants and to make them complain of noise. 338 CHAPTER 25 1959 Guide 75 120 -um *400 75 150 300 150 300 600 ---C"200------i-o - - -2S0 _ iso _r`w -200 oc < 0 no - -70 ____ _ - - -- b0 O - -50 70 CC -- 60 O -- so' . -- ISO OJ O - -20 oO 90"-15 d -- 60 30 Ul cc 600 1200 -250 --2 DO 30 1200 2400 2400 4600 -300' ' 4600 9600 ^200 450 ' ri--too ^-70 - -70 -'60 _ - SO " -40 - - 60 ' -- 50 PHONS-SONES 130 --|--soo -- 400 --300 120 *-|-2S0 200 --ISO ~ --40 90 -1,0 0 u Ul o 7o-r5 "_2 z _- 3 ___-- 2 oz < 0 Ul > < -H U O 20 --1 75 75 ISO . 150 300 _ -4 _ --3 _ ~4 _ --3 - .5 - .4 - .3 300 600 600 1200 1200 2400 2400 4800 4800 9600 30 PHONS- SONES OCTAVE PASS BAND IN CYCLES PER SECOND .The takuhbd total hudnett h sons* can be converted to bedness level at phoos by meant of Ae nowogrum O (from Reference 3. Used by penmnrooj pig. 2 .... Nomograms Relating L, in Octave Bands to Loudness in Sanes Introduction of a continuous spectrum noise properly dis tributed as a function of frequency produces a quieter condi tion even though the background noise is actually higher. Rumbles, rattles, audible single frequency components, beats between components, and intermittency in a noise often make it objectionable even though the noise as measured seems to meet the criterion. Noise Specification .. There are at least four possible ways of specifying the noise. The first way is amply to give the octave band spectrum of the noise. This method provides the information that is essential to the design engineer and no substitute can suffice. The other three of these methods of specifying noise are single-number numerical quantities that indicate something about the in fluence of tiie noise on the average human being. These three methods are useful as summaries of the octave band spectrum, but, taken separately, they are of limited value to the design engineer. The definitions of each of four commonly used ways of specifying noise are as follows: . - 1. Ociave Band Spectrum. The octave band spectrum is com* firised of the readings of sound pressure level in the eight octave requency bands (see the section on Acoustical Terminology). The readings are taken with the sound level meter weighting Sound Control 339 networks set on flat (C-scale) and the units are decibels (dbc). The specification of a complete octave band noise spectrum is necessary for satisfactory acoustic design in all eases. 2. Speech Interference Level SIL. The speech interference level is a single number found by taking the arithmetic average of the sound pressure levels in the three octave frequency bands 600-1200, 12CD-2400, and 2400-4800 cps. The unit is the decibel (db). The speech interference level indicates the ease of speech communication in the presence of the noise so rated. 3. Loudness Level L#. The loudness level is a single number computed from octave band levels according to the procedure following. The unit is the phon. To obtain the loudness level in phons, obtain the sound pres sure levels in the eight octave bands and read from Fig. 2 the loudness in sones for the respective bands. The sum of the loud nesses will be: . Ztf - AT, + N, + AT, + N. + N. + AT, + AT, + AT, (10) The loudness in tone* of the total noise is given by ' A? - AT. + 03 (SN, - AT.) (11) where Nm = the loudness of the loudest band. 2N{ = the sum of the loudnesses of all eight bands. To convert from loudness in sones to loudness level in phons, use Equation 9 or the nomogram at the right-hand ride of Fig. The loudness level in phons indicates the subjective loudness but does not indicate the ease of speech communication. 4. Sound Level. The sound level is a single reading on the sound level meter with the meter operated as follows:** Sound-level Range Weighting Uni Below 55 db................... 55-85 db.......................... Above 85 db................... A B C (Flat) dba dbb dbc Sound level measured with the A-scale can be correlated most closely with speech interference level but the two are not nu merically the same. The C-scale is always used with the octave band analyser and is used where otherwise specified. Criteria Noise criteria have been developed from detailed studies and engineering experience in a number of architectural spaces.* The acceptability of background noise for various types of activities normally performed in rooms and enclo sures can be related to two principal characteristics of the noise: (1) Speech interference level, SIL, and (2) Loudness level, Lh . Definitions of these two quantities are given in the preceding section on Noise Specification. The speech inter ference level is governed by the amount of higb-frequency noise (between 600 and 4800 cps) and the loudness level is governed by both the high- and low-frequency noise. For most types of spaces the loudness level in phons is 22 to 25 units higher than the speech interference level in dbc. However, for factories, sports coliseums, restaurants, and similar spaces where cost of acoustic treatment dictates a maximum amount of compromise, the loudness level may rise as much as 30 units above the speech interference level. Acceptable background noise criteria have been established for these two conditions and are presented in Figs. 3 and 4. Each curve is designated by a number indicating the speech interference level obtained. The numbers in the first column of Table 1 and Table 2 identify the curve which defines recom mended noise levels for the various types of spaces listed. With regard to the choice between Figs. 3 and 4, Fig. 3 should be used whenever possible, particularly where there is a possibility that the sound may be fluctuating, such as often occurs with turbulence in a ventilating system. Fig. 4, or numbers in the range between Figs. 3 and 4, may be used when economic factors dictate a compromise and when there is a definite assurance that the noise will not be of a fluctuat ing type. In engineering design, all eight octave hand levels selected from the curves of Fig. 3 or 4 should be used. In construction specifications, reference may be made to The Guide and the selected NC or NCA curve may be referred to by number e.g., NC-35. Where octave band analyses of the noise cannot be made and a rough approximation of accepted criteria must be ob tained by use of a sound level meter only, the A-scale values which would be read for the noise spectra specified in Column 1 are given in Column 2 for comparison purposes. It should be understood, however, that an A-scale reading gives a measure of the overall noise using a weighted network; it does not specify the spectrum. For example, the noise 'spectrum shown as NC-25 in Fig. 3 would give an overall A-scale meas- urement of 35 dba, but a measured value of 35 dba does not mean that the actual noise measured has the spectral shape or is as satisfactory as the specified NC-25 spectrum. The lack of octave band analysis can be partly offset by a subjective observation; if the noise sounds unnatural because of excessive amounts of high pitched or low pitched noise or has particularly noticeable amounts of pure tones, the spec- bum will probably depart widely from the specified one. In such cases it is advisable to make an octave band analysis of the noise, if possible. KINDS OF NOISE The noise introduced into a room or building by ventilating or air-conditioning equipment may be divided into two gen eral kinds, depending on how it reaches the room: 1. Noise transmitted through the duds. ' a. From equipment such as fans, motors, sprays, etc. b. From outside, and transmitted through duct walls into air stream. c. From duct wall vibrations, transmitted into air stream. d. From air currents, including eddying noises. e. Cross talk and cross noises between rooms connected by the same duct system. /. From dampers and air valves located near branch duct take-offs and outlets. g. Noise produced by grilles or diffusers. 2. Noise transmitted through the building construction. a. From machine mountings as vibration. b. From equipment through room wall surfaces. The following text will present data and discussion of meth ods whereby solutions ol the noise problem can be obtained when the allowable room noise level, and the path through which the noise reaches the room, are known. NOISE GENERATED BY FANS Aerodynamic noise from all types of fans may be broadly divided into a rotational component and a vortex component. The rotational component is associated with the impulse given to the air each time a blade passes a given point and is hence a series of discrete tones at the fundamental blade pass- ing frequency and harmonics thereof. The vortex component of noise is largely due to the sheddingof vortexes from the fan y c 340 CHAPTER 25 1959 Guide Eodi NC curve bat a !oedit*** level in phont that h 22 unit* greater titan fit* Speech Interference Level in dedbef* (expressed by the NC number of (be curve). These curve* fhoatd be used in design or specifications wherever a favorable relation between (he low frequency and the high frequency portion of (he spectrum is dented (see text). Hg. 3 .... Criterion Curves for Use with Table 1 in Determining'the Permissible (or Desirable) L, Values in 8 Octave Frequency Bands Same at fig. 3 excepf (hot each NCA curve hat a hudnest level to phont tiol it 30 unit greater titan (he Speedt Interference Level m decibel* (ex preued by the NCA number of (he curve). These curve* may be used In design or specifications in place of (hose of Fig. 3 wherever economy dictate* a maximum compromise and where, in addition, tit* fan and turbulence noise is steady end free of low frequency pare ton* components (see text). blades. It is random in character and has a continuous spec* trum over a wide range of frequencies determined by the fan geometry and operation. It may also have many nonhannonic single-frequency components determined by blade geometry and local air velocity. Since the laws of generation of these two types of noise are different, they will vary in importance for different types of fans and operating conditions.*-7 In addition to aerodynamic noise, there are usually several non-aerodynamic sources of noise in equipment involving fans. Such sources include noise resulting from unbalance, bearing noise, brush noise, magnetic noise, and belt noise. The number of blades of a centrifugal fan generally is governed by optimum air-flow design. The noise generation decreases but slightly for more than the optimum number of blades. . Powerful tones of definite pitch may be generated in fans when the wakes from the impeller blades impinge on an ob struction such as a badly located or shaped cut-off in a centrif ugal fan, or stints or motor supports which are badly shaped and too close to the impeller of an axial flow or propeller fan. This interference noise has the same frequency characteristics as rotation noise.* A shroud around a propeller fan may serve to reduce noise considerably if it is working properly. Such reduction is gen erally most effective at the higher harmonics. However, if the flow breaks down over part of the shroud, the noise may be come considerably worse than for an unshrouded case. , As the operating pressure across axial fans is increased the maximum sound intensity is shifted from the fundamental Fig. A .... Criterion Curves for Use with Table 1 in Determining the Permissible (or Desirable) Lp Values in 8 Octave Frequency Bands . to higher harmonics. This effect is not observed for centrifugal fans. Effect of Fan Parameters on Noise vs. Performance Fan Laws. The principal laws governing the- mechanical performance of a fan, whether centrifugal or axial, are fairly well established and are given in Chapter 22. ' Fixed Point of Rating. A fixed point of rating of a given size fan at a given speed is one for which the capacity (volume flow) is chosen as a given fraction of the free delivery capacity. Having chosen this capacity ratio, the ratio of pressure to the static no-delivery pressure is determined. This fixed point of rating will have a fixed efficiency within the limitation of cer tain manufacturing details. The fan laws serve to relate the performance of two members of a symmetrical series of fans operating at the same fixed point of rating whether at the same or different speeds. - Correlation of Fan Noise with Size, Static Pressure, Speed, and Capacity. The empirical relations between the noise gener ated by a fan and its size, static pressure, speed, and capacity are as follows: Change in overall sound power level varies as: - 70 logit(si*e*/sisei) + 60 logn(speedi/speedi) (12) 20 logi*(sire*/sizej) + 25 logii(pressuret/pressurei) (13) Sound Control 341 10 Iogi*(capacityi/c*pacityi) + 20 Iogi#(pressurej/pressurei) (14) Table 1 .... Recommended Noise Criteria for Rooms* NvIm Level* te be Atenured b tfecccupted * These relations also apply only for a fixed point of rating. A double width fan is essentially two fans of the size, speed, and sound pressure level and therefore its sound- power level will be 10 logit 2 or 3 db greater than for the single one. Example t: Consider a 36H-in. diameter fan operating at 700 rpm. If it produces a noise level of 70 dbc what will be the level if a 49-in. diameter fan operating at 1000 rpm is substi tuted for it? - . Solution: From Equation 12, 49 1000 Change in level -- 70 logi* --36---5 + 50 login 7--0--0 * 168 db Type of Space Recommended Name Criterion Curve Computed Equivofenl Sound Level Meter ' Keodmgs* Weighting Scole-A dba Broadcast studios................................ Concert halls........................................ Legitimate theaters (500 seats, no amplification)................................... Music rooms.......................................... Schoolrooms (no amplification)___ NC 15-20 NC 20 . NC 20-25 NC 25 NC 25 25-30 30 30-35 35 35 Noise level of second fan = 70 + 168 = 868 dbc Conference rooms for 50................... NC 25 Apartments and hotels...................... NC 25-30 35 35-40 Fan noise does not follow equations exactly. The radiated Assembly halls (amplification).... NC 25-30 35-40 sound power of a centrifugal fan, for example, is not all con Homes (sleeping areas)..................... NC 25-35 35-45* centrated on the blade frequency. While the overall sound . Conference rooms for 20................... NC 30 40 power level seems to follow these equations fairly closely, the Motion picture theaters.................... NC 30 40 various components in the different frequency- bands may ' Hospitals................................................ NC 30 ' 40 show greater deviation. In the case of axial flow fans there is Churches................................................ NC 30 40 a wider range in characteristics of the vortex noise, so it would Courtrooms................................. NC 30 40 be expected that a slightly greater deviation from these equa Libraries................................................ NC 30 40 tions exists than for centrifugal fans. This is particularly true Small private offices.......................... NC 30-35 40-45 as speed is increased. The fundamental or blade frequency Restaurants........ ................................ .NCA 45 55 exists over a wider range of pressure in the case of the cen Coliseums for sports only (ampli- trifugal fan. In the axial fan, the harmonics are more easily fication)..................................... ......... NCA 50 60 excited and often the second and third harmonics,exceed the Stenoeranhic offices (tvoine and level of the fundamental.* - business machines)......................... NC 50 60 Specific Plots Factories................................................ NCA 40-65 50-75 Curves which describe the characteristics of an entire series of similar fans can be plotted by using dimensionless,coor NcU: Etch noise criteria curve is t eode for specifying permissible sound pres sure levels in eight octave band*. It is intended th*t in no one frequency bend should the specified level be exceeded. The computed equivalent db* numbers dinates.7 To describe the pressure characteristics the pressure coefficient *ft can be plotted against the flow coefficient <j> as shown in fig. 5, where in the right-hand column ere presented for information only end ere no longer recommended for use ia specific*tinos. Ventilating systems should be operating endoutside noise sources, traffic conditions, etc., should be normal when measure ments are ' p, total pressure . * If the noise is predominantly in the speech bend* to that the spectrum does not have the shape of the recommended noise criterion curve, the recommended f(y)(D)(rpm)1 /wheel peripheral\ 4005 J ^velocity pressureJ (15) dba numbers should be lower by S dba. b Room air conditioners made prior to 19S7 commonly produce levels uf SO to 0 dba in sleeping arms. Table 2 .... Recommended Noise Criteria for Offices* NC Curve of Fig. 3 Communication Environment Typical Applications NC20 to NC30 NC30 to NC35 NC35 to NC40 NC40 to NC50 NC50 to NC55 Above NC55 Very quiet office--telephone use satisfactory--suitable for large conferences. Quiet office; satisfactory for conference at a 15-ft table; nor mal voice 10 to 30 ft; teleph'ono use satisfactory. Satisfactory for conferences at a 5-8 ft table;'telephone use satisfactory; normal voice 6 to 12 ft. Satisfactory for conferences at a 4-5 ft table; telephone use occasionally slightly difficult; normal voice 3 to 6 ft; raised voice 6 to 12 ft. . Unsatisfactory for conferences of more than two or three people; telephone use slightly difficult; normal voice 1 to 2 ft; raised-voice 3 to 6 ft. Very noisy; office environment unsatisfactory; telephone use difficult. Executive offices and conference rooms for SO people. Private or semiprivate offices, reception rooms, and wmn.il conference rooms for 20 people. Medium-sired offices' and industrial business offices. Large engineering and drafting rooms, etc. Secretarial areas (typing), accounting areas (business machines), blueprint rooms, etc. Not recommended for any type of office. * Noise measurements made for the purpose of rating the noise level in an office by comparison with these criteria should be performed with the office in normal operation, but with no one talking at the particular desk or conference table where speech communication is desired (he-, where the measuremeat is being made). Background noise with the office unoccupied should be lower by approximately 5 to 10 units. I 342 CHAPTER 25 1959 Guide Haas* data arw for a partiadar fan. Ibn qwcntiScj d, and PWI, ora diicutrod in fiw t*xl. Svdi curve* apply to aO font in a daufar rent*. Rg. 5 .... Specific Fan Characteristic Curves, Including Specific Sound Power Level . p, f (ir)Q?)(rpm)*l I 4005 J static pressure /wheel peripheral\ yvelocity pressureJ (16) (efm)/(Outlet Area) outlet-velocity ()/(0)(rpm) wheel peripheral velocity D = wheel diameter, feet, p, = static pressure, p, = total pressure. Such curves apply to all Ians in a similar series, i.e., a series of fans differing in rise only while preserving complete simi larity in shape by having all linear dimensions changed in the same proportions. - An overall specific sound power level PWL, in dbe as shown in Pig. 5 can also be defined that will be applicable to all fans in a family.7 It is obtained by means of Equation 18 which follows: PWL. - PWL - 10 log,*!?-?*] dbe . (18) where - 9 -- quantity of air discharged, elm. p -- pressure, inches of water. ' PWL -- sound power level actually measured. . Since static presuie p, is more frequently measured for fans than total pressure Pt, p, may be used under most normal operating conditions (when the difference between p, and p< is less than 20 percent) and the error will then be less than 1 db. Near free discharge, p. becomes zero and p, must be used. In other words, PWL. is the sound power level that a similar (although hypothetical) fan would produce when operating at 1 cfm and a total pressure of 1 in. of water. As an example, the specific power level for one fan tested is shown on Fig. 5. Although few data are available to confirm the conclusion, it is indicated that such a plot also holds throughout a series of fans for all eight of the frequency bands provided rotor or blade passage frequencies are not predominant. Approximate Overall Sound Power Level In practice, data of the type shown in Fig. 5 are usually not available. Hence, in design an estimate has to be made of the overall sound power level and of the shape of the noise spec trum. Tests on centrifugal fans ranging in size from 0.01 hp to 100 hp show that the sound power level in a duct either upstream or downstream from the fan can be found within 4 db from the simple relation:*- where PWL -100+10 logj.W* + 10 log,p dbe . (19) Wg -- nameplate electrical horsepower of the motor driving - fan (assuming that the motor is operating near rated bp). ' . p -- pressure head, inches of water. dbe = number of decibels re 10"u watt. ; (See discussion following Equation 18-) The assumption is made that the fan is being operated near the knee on its operating characteristics, i-e., near maximum efficiency or near the minimum in the curve of specific sound power (upper curve on Fig. 5). By assuming a fan mechanical efficiency of. SO percent, Equation 19 can be put in the form of Equation 18 with PWL. - 65 dbe, i.e., PWL -- 65 + 10 logug + 20 log,*? dbe (20): 9 -- air quantity, cfm. . p -- pressure head, inches of water. (See discuasioo after Equation 18.) It should be emphasized that Equations 19 and 20 are in tended to be used only when actual noise data are not avails- rXCOUEMCY BMO M CYCLE* K* C<X 77m overall power level h Brsf determined from Equation 19 or 20 and U added algebraically to the ordinat* in fig. 6. Acoustics bf l. L fleranefc (McGraw-Hill, 1954 Second Printing). Used by peramroo. Rg. 6 .... Chart for Determining the Sound Power Band Levels for Ventilating Fans of Two Types Sound Control 343 ble. All fans of the same power input are not equally noisy. The example illustrated in Fig. 5 demonstrates this fact since the minimum value of PWL. for this particular fan is 69 db, 4 db higher than the value used in Equation 20- It is on the edge of the stated limit of approximation 4 db. Approximate Octave Band Spectrum Within about 4 db approximation, and assuming no tur bulence in the duct or the coupling between it and the fan, the octave band spectrum for a centrifugal fan, relative to the overall sound power level, is given in Fig; 6. TjmitoH data on vane-axial fans,11 where sound pressure level measurements were made in the discharge duct, indicate that the overall sound power level is about the same as that for centrifugal fans. However, the spectrum shape of the vaneaxial fan noise has a shape something like that shown in Fig. More recent free field measurements on aria) fans indicate that perhaps the drop in level at the high and low ends of the spectrum are more pronounced.* The solid linn in Fig. 7 is typical of the sound power spectrum for the axial fans re ported, as taken directly from the free field measurements. Application of a correction for the end reflection losses from tiie discharge opening (see Fig. 11) gives the dashed curve in Fig. 7, which corresponds to the relative sound power level in the duct. This spectrum shape for the axial fan appears to be based on more extensive data than those of Fig. 6. . NOISE GENERATED BY GRILLES AND DIFFUSERS Grille Noise The subject of grille noise has not been covered thoroughly in the literature. The information given in this chapter haa been taken from the advertising literature of several grille manufacturers and from recent experiments at the Massachu setts Institute of Technology. . In general, grille noise at the lower frequencies is dependent primarily on the size and shape of the grille opening, on the mass flow per minute, and on the temperature of the air. At the higher frequencies, the noise is determined primarily by the area of the grille, the velocity of air through the free (open) areas (not the core or nominal area), and the pressure drop across the grille. - For two simple types of grille, stamped and deflector vane, power levels are given in Fig. JL-These power levels are given IN C s/ FREE FI LO 7-5 ISO 300 OOO 1200 2400 4000 AO 300 . OOO - 1200 2400 4600 IOOOO FREQUENCY SAND IN cycles per second ,Rg. 7.... Sound Power Spectrum for Single-stage Axial Fan* TTm noi*e is exprested as fhe sound power Serai a dbe in eoeb oF (ha three Speadi hhffasiict bands [fWLstil. Rg. 8____ Grille Noise for a Grille Area of One Square Foot in terms of the speech interference level, PWIeiL . Conver sion to the speech interference level in db in the room at a listener's position is described in the section on Determina tion of Room Levels. In the absence of more complete infor mation, it may be assumed that the power levels of the noise produced by the grilles themselves at low frequencies are in consequential. Fig. 8 is for a grille core area of 1 sq ft. Correction to other areas of grille is made by the relation: Decibel addition -- 10 loguA db A -- core area, square feet. Values of the decibel addition for various values of A are given in Table 3. Table 3 .... Decibel Correction for Area A *q ft _ Decibel Addition A cq ft Dodbol Addition A tq ft Oedfeel Addition 0.5 . --3 10 23 46 8 16 20 40 9 70 18 12 100 20 13 200 23 16 400 26 Example t: Assume a deflector vane type of grille with a core area of 2 sq ft. Determine the sound power level in the speech interference bands for an air velocity of 2000 fpm. Solution: From Fig. 8. the PWLen. for a 1 sq ft deflection grille is 59 dbe. From Table 2, an addition of 3 more dbe is re quired, so that PWUil -- 62 dbe. Diffuser Noise Aside from the information furnished by diffuser manu facturers, to their users, on sound levels generated by air dif fusers, few other data are available. Recently, however, some test results on several types of ceiling air diffusers have yielded a satisfactory correlation of the sound generating characteris tics of these devices.1* The data, covering ceiling diffusers ranging in size from 4- to 18-in. neck diameter, show that the X Sound Control 345 Table 6------ Power level Attenuation at Duct Branches or Outlets Branch Duct Area Stint of Branch Area* Attenuation db Ratio Branch Duct Area Sum of Branch Area* Attenuation db 1.0 0 0.25 6 0.8 1 0.2 7 0.63 2 0.16 8 0.5 3 0.13 9 0.4 4 0.1 10 0.32 5 to aay branch may be calculated aa 10 login of the ratio of the branch area to the total area of all branches leaving the junc tion. Generally the total area of the branches leaving a junc tion is greater than that of the duct entering & junction; there fore, the area of the branch should not be divided by the area of the supply duct. In a complicated branched system, errors . incurred by such a practice may accumulate to several db. Table 6 gives the db reduction for various ratios of branch duct area to the total branch duct area. Square Comer Bends Square comer bends can be quite effective in noise reduction provided they are widely separated in tire system. The noise reduction for a single square corner bend with no turning vanes, unlined, is'shown in Fig. 10 Part A. Turning vanes are usually employed in square comer ducts. When the width of the turning vanes is small, say leas than one-fourth wavelength of the mund, they do not affect the noise reduction. At higher frequencies, they decrease the noise reduction substantially below that shown in Kg. 10 Part A. When a square comer bend is iinM with sound absorbing material, the lining should be extended several duct widths beyond the comer in the direction of sound transmission. For square bends lined in this manner the attenuation may be estimated from Fig. 10 Part B. End Reflection Losses All of the noise power that is produced in a duct by a fan (or by turbulence) does not radiate from the end of a duct into the room, instead, part of the power is reflected back from the end toward the fan. The amount of noise power reflected is related to the product of the frequency of the sound and the length of a duct side L, assuming that the duct is square. If the duct is not square, the value of L is taken to be approxi mately equal to y/LtLf. The end reflection loss is shown in Kg. 11 for two cases: (1) a duct ending in free space ftnd (2) a duct ending flush with the wall. Duct lining Procedure In the piast, the most common method of obtaining sound absorption in ventilating systems has been to linn the duct with absorbing material. It is usually more convenient to linn all four sides of the duct, but a lining on one side over a longer length of the duct will, in genera), give the effect for the same area of applied acoustical material. Subject to certain restrictions, the attenuation of a fully lined duct to single frequency sounds may be expressed by the approximate Equation 22.1* where R = 12.61 A db (22) R ~ attenuation, decibels. I -- length of lined duet, feet. P = perimeter of duct, inches. A = cross-sectional area of duct, square inches, o " absorption coefficient of lining (a function of fre quency).1* 10..... Attenuation in Decibels Provided by (A) Unlined Bend, and (B) Lined Bend in a Duct with the Lateral Dimension D FREQUENCY X LENGTH X!0~3*/L/IOOO IN. CPS - INCHES A" oh*ei**o equois fl/1000 where f Is the geometric mem frequency of on octave bond in cpt end l is the duct distension in incites. Two eases ore shown, with the chief end Audi m the woti and with the duct end projecting Fig. 11.... End Reflection losses in Decibels at the Open End of a Square Duct of Area Is TMT 346 CHAPTER 25 1959 Guide Table 7____ Attenuation Data for Typical 1-in. and H-m. Thick Duct lining Board I-Jadt Thkhma }^4adt Thicknea Cydas fur Absorp Stcond tion CoBffidecR a tr14 Attenuation 4b Absorp tion Co tffkfettf a 14 Alternation db 128 0.12 0.051 0M`j 0.09 0.034 043 `j 256 0.38 0.26 3.2I 0.25 0.15 ig`i 512 0.70 0.60 -4 0.40 0.28 35lj 1024 p 0.80 0.73 9.2 lj 0.72 0.63 7.91 2048 0.79 0.72 0.78 0.71 8.9 4 This formula was empirically developed for a set of duct pispfl mnging from 9 x 9 in. to 18 x 18 in.; for cross-sectional dimension ratios of 1:1 to 2:1; for frequencies between 256 nH 2048 cycles; and for absorption coefficients between 0.20 and 0.80. The duct lining material used was 1-in. rock wool ahapt. The absorption coefficients of a material of this type in one-half and one-inch thickness are listed in Table 7. It is alsn possible to calculate the absorption by a very com plicated mathematical theory.17* u Such calculations are in substantial agreement with Equation 22. This equation may be in error when applied to other types of duct lining and to duct sices and shapes greater than those specified. With every application, the use of sound absorptive mate rial should be considered in the dual function of insulation and sound absorption. It has been shown theoretically that the reduction (in decibels per linear foot) of sound transmitted alnng a duct linarf with sound absorbing material is related in a rather complicated manner to the site and shape of the duct, to the frequency of the sound, and to the sound absorbing characteristics of the lining. Experimental evidence likewise indicates that there is no ample formula involving the varia bles which will apply accurately to all cases. However, it may be stated generally that the attenuation in decibels at a given frequency is directly proportional to the length of lined duct. It decreases as the cross-sectional area increases, and increases as the aspect ratio is increased. Rectangular Cells (Plate or Cell Absorbers) If the available length of duct between the main duct (or the fan) to the grille is shorter than the length of lining indi cated as necessary by Equation 22, the duct may be sub divided into smaller ducts as shown in Pig. 12, or it can also be even more subdivided by an egg-crate construction. In such a construction in which all the subdivided ducts are the MTrn. size, sound will be equally absorbed down each channel. It is, therefore, ooly necessary to calculate the sound attenua tion of an individual channel. For this. Equation 22 is ade quate, assuming that the thickness of the material is halved if it forms a common splitter between two cells. When the number of splitter plates or cell partitions is large, the percentage free area of the gross duct rise may be mate rially reduced. This leads to a further sound attenuation. Values of the attenuation possible, due to this cause, are given in Table 8. Table 8 .... End Reflection of Plate or Cell Absorbers Percentage Free Ana of Absorber 50 40 30 25 20 . Attenuation db 1 2 456 Plenum Absorption . In systems where individual ducts are directed to a number of rooms, and sound treatment is required in every duct, a sound absorption plenum on the fan discharge as shown in Fig. 13 will often prove the most economical arrangement. Based on both experiment and ray acoustics theory, the following approximate expression has been derived for acoustic plenum attenuation.1* ' db (attenuation) -- 10 loj 8, cos 9 1 - a 2P + =S. (23) A. Unfrnod dud fl. Lrn#d dud C. SpCHor ptate typo absorber 0. Cefl-fype absorber Tbe open oree h (be came for eod> case drawn if T in. ffscfc Fig. 12____ Acoustic Treatment of Ducts a = absorption coefficient of the lining (dimensionless). 5, = plenum exit area, square feet. S* = plenum wall area, square feet. d = distance between entrance and exit, feet. 9 = the angle of incidence at the exit, i.e., the angle which the direction d makes with the normal to the exit opening. For frequencies sufficiently high so that the dimensions of the plenum exceed about one wavelength, Equation 23 will predict the sound attenuation within a few decibels. At low frequencies, somewhat more attenuation is realized than will be computed by Equation 23, due to the existence of a reso nant muffler action in the duct-plenum system. Outlet Sound Absorbers Outlet sound absorbers are rectangular or plate cells in stalled directly behind an outlet or they may be the lining of a pan or plaque outlet. They are particularly effective in the Sound Control OHTUSER VANES MUSLIN SURFACE / DIFFUSER VANES 347 SHEET METAL HOUSING LINING, 2 IN. MUSLIN J . COVERED ftOCK WOOL DwCT BRANCHES PLAN I BOARD^ (FIRE RESISTIVE)^ 7 'I. AIR SPACE / la2 IN. WO< SHEET METAL HOUSING CONSTRUCTION OCTAIL I IN. SOUND ABSORBING BOARD Fig. 13 .... Absorption Plenums With and Without Sound Cells ELEVATION elimination of high frequency whistles which are generated by air flow in the ducts. They are also employed in large systems with long runs where only a few outlets near the fan require treatment. Frequently outlet cells are the only means of cor recting existing noisy installations, as the duct sections di rectly behind the outlets may be the only sections accessible for treatment. (See Fig. 14.) . Package Units . Package units for attenuating sound in ducts are coming more and more into common use. These units have the ad vantage of providing, in a short length, a known amount of noise reduction with a minimum opportunity for errors in installation and for erosion of materials. The cost of inspec tion of the completed job is eliminated and the outside di mensions of the duct can be reduced as compared to a duct. These units are available in sizes to fit 6 x 12 in. ducts up to 80 x 84 in. ducts. Charts are supplied by the manufacturers giving the attenuations and pressure drops for different types of units. In Figs. 15 and 16, the noise reductions and static pressure drops for several types of package units are shown. Manu facturers' literature should be consulted for exact values. Selection of the Absorptive Material When a sound wave impinges on the surface of a porous material, a vibrating motion is set up within the rtwaII pores of tiie material by the alternating sound waves. As the ratio of the cross-sectional area of the pores to their interior surface is small, tiie resistance to the movement of air in the pores is farge. This viscous resistance within the pores of the material converts a portion of the sound energy into heat. The decimal fraction representing the absorbed portion of the incident sound wave is called the absorption coefficient. Considerable absorption may also result, particularly in the low-frequency range, from the flexural vibrations of the duct. In the selec tion and application of the absorptive material, the following points should be considered: 1. For the absorption of the low-frequencies below 500 cps the material should be 2- to 12-in. thick. Thin materials, par ticularly when mounted on hard solid surfaces, (rill absorb only the high frequencies. . 2. In order to provide as much low-frequency noise absorp tion as possible by means of flexural vibration, it is desirable to fasten the absorptive panels discontinuously. This result may be attained to some extent by spot cementing, but better re sults are obtained when it is possible to fasten the absorptive panels to furring strips, leaving an air space behind. However, the exact resonance characteristics of the panels, and thus their absorption, are so unpredictable that flexural vibration cannot be relied upon for a specific value of attenuation. Requirements for a good sound absorption material are: (1) high absorption at low frequencies,4* (2) adequate strength to avoid breakage; (3) fire resistance and compliance with national and local code requirements; (4) low moisture ab sorption; (5) freedom from attack by bacteria and algae; (6) low surface coefficient of friction; (7) particles should not fray off at tiie higher design velocities; and (8) freedom from odor when either dry or wet. DETERMINATION OF ROOM LEVELS In tiie previous sections on fan and grille noise, sound power levels were given in dbe referred to lChu watt. These quan tities as they appear at the duct termination (grille) must be SOUND ABSORPTION BOARD t Fig. 14 .... Outlet Cells for Pan Outlets or Grilles 3 348 CHAPTER 25 1959 Guide Rg. 16____ Approximate Pressure Drop Across Typical Package Units Fig. 15 .... Typical Values of Sound Attenuation Through Several Types of Package Units in. If the duct is rectangular, the value of Q should be com puted for L equal to the smaller dimension. - The room constant R is defined by the equation converted to sound pressure levels' in the room, because it is sound pressure to which the ear and the sound level meter respond. The sound pressure level at a distance r from the grille opening and at an angel 6 with respect to an axis per pendicular to its surface is given by the equation*9 L, - PWL + 10 log* + |) + O-5 dbo (24) R - *S/(i - a) (25) where . 5 = average sound absorption coefficient (dimensionless) for the room at the mid-frequency of the band of noise being considered. S -- total area of the boundary surfaces of the room, sq ft. where PWL = sound power level emitted at the duct termination and is the power summation of the attenuated fan noise and the grille noise in dbe (see Example S). Q -- directivity factor and is a dimensionless function of 8. r -- distance from the duct opening, feet. R -- the room constant, square feet. (ft increases with the amount of acoustical absorption in the room and generally depends somewhat upon frequency.) In Fig. 17 four methods are shown for terminating a ven tilating duct in a room. In each of these cases, the noise power radiates into the room. Low-frequency sounds radiate equally in all directions. High-frequency sounds tend to beam in the . direction the duct opening is facing. The magnitude of this harming effect is described mathematically by the directivity factor Q. After the sound at any frequency has reflected from a wall, it generally travels around the room many times to produce reverberant sound. This fact appears in Equation 24, wherein the first term in the parenthesis described the direct unitnd (prior to reflection) and the second term described the reverberant sound (the result of many reflections). The directivity factor Q is of importance only when the is near the duct termination, i.e., when r is small. At large distances, i.e., when the first term becomes negligible compared to the second, the listener hears only the reverberant Bound. a For the four duct positions of Fig. 17, approximate values of Q are given in Fig. 18 for 0--0 deg and for 6 = 45 deg. The is the product of frequency times L assuming that the duct is approximately square with an area of L* sq Where a room.contains several surfaces, each with different absorption coefficients, the average absorption coefficient may be determined by the equation Sira + Sm + - Si + Si + * (26) A. Duet projecting m (be room ' S. Duct in tf>e center of and ftush with the wafl C. Duct in the center of one edge O. Duet in the comer _ .The fistener l is at distance r end engfo 8 from the duct opening. Rg. 17 .... Four Typical Means for-Terminating a Ventilating Duct in a Room Sound Control 349 - reading room as a result of the ventilating system, both for the position^ of the nearest listener to a grille, and for a position remote from the suppiy grilles since it is impossible to ieii be forehand which will be greater. The required attenuation for acceptable octave band noise levels will then be determined. Analysis of Fan and Duct System The acoustic power level of the fan should be computed from Equation 18 when the specific power level is available. In this example it is assumed that the specific sound power level is not known. Therefore, employ the approximate Equations 19 or 20. From Equation 19: PWLw,,, ad) = 100+10 log 15 + 10 log 2 - 114.7 dbe or from Equation 20: - Rg. 18 .... Directivity Factor Q for the Four Duct Configurations of Rg. 17 PWL(dM, ab> -65+10 log 25,000 + 20 log 2 = 115 dbe ' which agreement is better than the accuracy expected from these equations. Of this total acoustic power generated by the fan the main interest is in the part that reaches the reading room. At each duct branch the powerwill divide approximately as the ratio of the branch duct area to the total duct area after the branch. Thusat Station B (Fig. 21) the acoustic power delivered to the .. 18 x 48 in. duct, neglecting any attenuation.in the system, will be , PWL<ABetBC> -- PWLldo(, AB) + 10 log (Abrafc/Atul) where Si, St -- the areas of each type of absorbing material, ai, at etc., -- the absorption coefficients of each type of material at the mid-frequency of the band of noise, being considered. (Valuesof a for manymaterials are published by the Acoustical Materials Association.") For estimating purposes, approximate values of the room constant R may be obtained from Fig. 19 as a function of room size for five classes of rooms. The value of the second and third terms of Equation 24 (including 0.5 db) is plotted in Fig. 20 with distance r from the source as the abscissa, with the sound pressure level in decibels, as the ordinate and the room constant ft in sq ft as the param eter. The directivity factor Q is given at the bottom left-hand, side of the graph. The procedure for using the graph is as follows: Determine the room constant ft and the directivity factor Q for the particular direction 8 of interest. Enter Fie. 20 at the bottom at the distance r. Then move diagonally to the left until the value of Q is reached. Then move vertically until the value ft is reached. Then read the relative sound pressure level from the ordinate. An example is shown by. the dotted line in Fig. 20 for r -- 7 ft, Q -- 2, and ft -- 2000 eq ft. The relative sound pressure level is added algebraically to the sound power level to yield the sound pressure level at the distance r and the angle 8 in the room (see Equation 24). ' It is seen from Fig. 20 that the noise from a.ventilating duct is less at distances far from it than nearby. Moreover, at large distances, the levels produced in the room depend only bn the power level of the source and the room constant and not on the directivity factor and the distance r. Example 8: To illustrate the application of the noise criteria and control procedures outlined in this chapter, calculation will be made for the required treatment for the ventilation system supplying the library reading room of Fig. 21. This room has a total volume of 80,000 cu ft and may be considered as an average room for acoustic properties (see Fig. 19). The total air supply to the reading room is 6000 cfm wbicn is equally divided between four 12 x 18 in. supply grilles located along one wall. The supply of outdoor air is from a central fan system which handles a total of 25,000 cfm at 2-in. water static pressure and requires a 15 hp motor. . Solution: It is necessary to determine the noise level in the - 115 +10 log f;--------- j* x 1*----------1- 111 dbe [_(24 X 48) + (18 X 48) J At Station C the.power division gives PWL(deCD) -- 111 + 10 log I ^ | 1_(1S X 24) + (12 x 48)J 108 dbe Thus neglecting, at first, the attenuation in the connecting duct Thmsm proportions ghrm S -- SISV**. The paronefor ii (he average sound-absorption coefficient for (he room. The (objective raltngt deod, five, etc* are fhm author's* and are net inecusarfy in standard on. from Reference 20.- Usod by permission. '. Rg. 19 .... Value of the Room Constant R as a Function of Room Volume for Rooms with Proportions of About 1:1.5:2 350 CHAPTER 25 1959 Guide ROOM CONST. R SQ FT as I 2 5 T . 10 20 01 STANCE r FROM ACOUSTIC SOURCE IN FEET SO ` 100 . ' SI-7V= ROOM CONSTANT IN SQ FT a = AVG. ENERGY ABSORPTION = TOTAL AREA OF BOUNDARIES COEFFICIENT OF THE OF ROOM IN SQ FT ` . SURFACE OF THE ROOM . THE ABSOLUTE SPL (DB RE 00002 MICROBAR) EQUALS THE SUM OF THE ORDINATE AND THE ; PWL '(08 RE I0-13 WATT) OF THE NOISE SOURCE AT NORMAL ROOM TEMPERATURE ANO ~ PRESSURE CONDITIONS. . Tbo Cctaner'* poiffian is of a distance r and an angle 0 with resped fa (he dud opening. Q it determined from 0 and from (he dud dunonnons (see Fig. 18). To ate (he graph proceed as for the example shown by (he doffed line for r = 7 ft. O ** 2, and B " 2000 ^ ft. The sound pressure level in die roam equals (he am of the ordhsafe and (he sound power leveL Normal room temperature and pressure conditions are atsussed. fig. 20 .... Curves for Determining the Sound Pressure Level in the Room Relative to the Sound Power Level . system, the total acoustic power delivered to the room by the fan will be 108 dbe. Assuming that the branch fittings at D, E, andF are similar to that at V in Fig. 21, the unattenuated fan acoustie power delivered to each of the four 12 z 18 in. grilles will be approximately ' - : . PWL(da Off) - 108 - 10 log 4 = 102 dbe -The octave band spectrum of the centrifugal fan noise is given by Fig. 6. This chart indicates that the power level in the first band (20-75 cps) will be about 102*1 or 101 dbe, and the power level in each succeedingly higher octave band will be 5 dbe less. These levels are entered m line 1 of the calculation Table 9. - The next step is to determine the natural duct attenuation between the fan discharge and the room supply grilles. From Table 4 the attenuation for straight sheet-metal ducts of medium size is 0.05 db per ft at all frequencies. Let us assume that.all of the ducts of-this system fall within this medium category^ The total length of the duct run from Statioa A to Station H, Fig. 21, is 90 ft. The straight duct attenuation is, therefore, 0.05 (90) -- 5 db, which is entered in line 2 of Table 9. It should be noted here that the ducts CD and DH of 12 x 48 and 12 x 15 in. dimensions, respectively, are of about the same size as those reported in Table 5. Hence if we assume the attenuation for these two bare ventilation duets can be taken from Table 5, it will be found that the straight duct attenuation between C and B (35 ft) will be approximately 10 db in tbe lowest two octave bands, 6 db in the third band, and 3 db for all octave bands above 300 cps. That is, using Table 5 for ducts CD and DH, and Table 4 for ducts AB and BC, the first three columns in line 2, Table 9, would read 12,12, and 9 db in that order, and the other columns would be unchanged at 5 db. It would appear, therefore, that the 5 db attenuation values for the lower three octave bands are probably overly conserva tive. The divided-flow fitting at B may be considered equiva lent in attenuation to-an 18-in. square bend. Values are read from Fig. 10, Part A and entered as line 3 in tbe calculation table. The rounded corners of the branch flow fittings at C, D, B, F, and O are assumed to have no attenuation. The 12 x 15 in. risers serving each of the wall grilles have a square bend (see Fig. 22), and attenuation values are read from Fig. 10, Part A and entered as line 4 of Table 9. Tbe attenuation due to the end reflection loss at the grille face is given by Fig. 11. For the 12 x 18 in. grilles used here L " \/l2 X 18 14.7 iu. Thus, for the first octave band. (20-75 cps), which has a geo metric mean frequency of 40cps,/L/1000 -- (40 X 14.7)/1000 = 0.58 and the end loss is 13 db. The attenuation in the other octave bands is similarly deter- Sound Control ; 351 Table 9 .... Summary of Calculations for Example 3 on Ventilating Noise levels tnLibary-Reading Room Horn - Octave Fregueix./ Sand* . 20 75- 150 300 600 1200 2400 4800 75 cps . ISO cps 300 cpi 600 cps 1200 cps 2400 cps 4800 cps 10,000 cps 1. PWL(daetOff)............................................. 2. Attenuation^ dB*t>.............................. . 3. Attenuation^^ B)............ .................... 4. Attenuation^besd m................................. 5. Attenuation^^ uo................................ 101 5 -- -- 13 96 5 -- -- 7 6. Total duct attenuation......................... 18 12 . 7. PWL(ffiiu ootuu...................................... 8. /L/1000 cps-in....................... .................. 9. Q.................. ................................ ............. 10. Rel.L, at 7 ft........................................... 11. L, at 7 ft................................................. 12. PWL{n iiiiim)......................................... 13. Rel.L* far field........................................ 14. Reverberant Lp....................................... 15. Criterion Lp............... .............................. 15. Required attenuation............................ 17. Attenuation 4 ft pkg. unit................... 83 0.5 2 -22 61 89 -26 63 60 3 7 84 1.3 .2 -22 62 90 -26 64 51 13 11 91 5 2 1 4 12 79 2.5 2.2 -22 57 85 -26 59 43' 16 14 86 81 ' 76 71 5555 7 7 ,6 11 4 7. 7 8 1 i --,_ " ' "_ 17 19 . 18 24 69 5.1 2.7 -21 48 75 -26 49 37 12 30 62. V 58-' ' . 10.2- 20.4 . 3.2 3.6 --20 -20 42 . 38' 71 . 67 -26 . -26 45 41 32 30 13 11 40 40 47 40.8 3.9 -20 27 56 -26 , 30 28 2 38 66 5 . 12 .-10--_ 27'. 39 . - 81.6 ' 4.1 -20 , 19 . ' 48 . .-26 22 27 -- 33 mined and entered in line 5 of Table 9: The total natural duct attenuation is now found By summing lines-2, 3, 4,' 5 of Table 9, and the result appears in line 6. This total attenu ation may now be subtracted from the unattenuated power level in line 1 to give the estimated acoustic power'level radi ated into the room from the outlet grille at Station B. Line 7 of Table 9 gives the result. - Determining Room Sound Pressure Levels - . The next step, then, is to calculate the sound pressure level at the position in the room occupied by the listener nearest to any one grille, and for tbe overall reverberant sound pressure level In the room due to the sound power radiated from all of the grilles. Fig. 22 shows that the position of the nearest listener is 7 ft from the grille. To determine Lp at this position, determine the directivity factor Q at 45 deg to the girlie face: this is found from Fig. 18. The parameter fL/1000 is determined by taking the characteristic length L as the shortest side of the grille face or 12 in. Thus, for the first octave band, /L/1000 = 40 (12)/1000 =* 0.48. This value together with all the-corre sponding values for the other seven octave bands are entered in line 8 of Table 9. Line 9 of the table gives the corresponding . directivity factors as read from Fig. 18, using curve B since the grille is flush with the wall but hot at on edge or comer. It was initially assumed that the library reading room had average acoustical properties, and consequently, the room con stant R in sq ft may be read from the line marked average room fig. 22 .. .. Locafion of Nearest Listener to a Supply-Grille 352 CHAPTER 25 1959 Guide of Fig. 19. For a total room volume of 80,000 cu ft the result is 2000 sq ft. The relative souDd pressure levels for an that if the grille size must be changed its correct value may be used in calculating fan noise attenuation. making use of the directivity factors and the room constant as found. The dotted line in Fig. X shows that the relative L, for the 20-75 epe band is --22 db. This relative Lr is entered in line 10 of Table 9. The sound pressure level at the 7-ft position from the grille is given by the addition of line 7 and line 10 in the calculation table. This result appears as line 11. CROSS TRANSMISSION BETWEEN ROOMS AND THROUGH DUCt WALLS Ducts serving more than one room permit cross talk be tween the rooms and should be lined with acoustical material. If there were only one grille in the room the calculation for room sound pressure level would be the only one required. How ever, since there are four grilles it is necessary to determine the general reverberant sound-pressure level in the room due to the acoustic power radiated from these four sources to see if it is greater than the previous calculation. Neglecting the small additional duct attenuation which occurs in the some what longer duct runs to the other three room grilles, the total acoustic power radiated from the four grilles will be four times that from one grille. Hence the total acoustic power level from all grilles will be 10 log4or6dbhigherthan from a single grille. In tine 12 of Table 9, therefore, enter the PWL of all grilles by adding 6 db to the single grille value of line 7. The relative Lp for an observer in the reverberant sound field is read from the horizontal part of the R = 2000 sq ft curve of Fig. 20 as --28 db, and entered in line 13 of Table .9. The sum ot line 12 and line 13 values from Table 9 gives, in line 14, the general rever- berant sound pressure level in the room. Comparison of line 11 and line 14 shows that the latter is 2 db higher at the lower fre quencies and, therefore, should be used in determining any noise treatment for the ventilating system or room. Where the rooms are close together and the ducts short, the ducts should be subdivided to provide ample acoustical treat ment. TAgging material similar in character to acoustical board, when placed on the outside of ducts, serves to prevent noise, originating outside the ducts, being carried inside the ducts and into the air stream. A case where outside lagging is desirable occurs when ducts originate at the fan in the equipment room and pass through this room on the way to the room being conditioned or ven tilated. Unless the ducts are lagged, some of the mechanical noise from air in the equipment room may be transmitted through the wall of the duct into the air stream, and thereby . carried into the room. In such cases, that portion of the duct * which is exposed to the sounds in the equipment room should be lagged with material, such as cork, pipe covering, or other sound damping material, to prevent the sound from entering the duct at this point. Numerical data are not available to Room Criteria For this example tbespeech interference level criteria will be used. Examination of Table 1 shows that an acceptable noise level for libraries will be given by the NC-Z0 curve of Fig. 3. The values read from this curve are entered as line 15 of Table 9. The difference between these criterion sound pressure levels and the computed in line 14 of the table gives the re quired attenuation for the ventilating system. This final result appears as line 16 in Table 9. Treatment permit a simple and practical calculating procedure to deter mine thickness of covering which should be used for this purpose. Laboratory measurements have shown that the loss through a sheet of No. 22 gage metal is 24 db. When a sheet of rock . wool insulation 1 in. thick and weighing 1.4 lb per square foot is added to this, the insulation value is increased to 29 db. In general, however, adding a layer of insulation or pipe cover ing does not materially increase the sound insulation value unless the material is dense, or unless it is surfaced with an The type of treatmentof the'ventilating system to obtain the attenuation given in line 16 of the calculation table will depend on many factors as discussed in the section on Sound Attenuation. One satisfactory treatment might employ a 4-foot package unit whose attenuation characteristics, as given-in Fig. 15, are entered in the final line 17 of Table 9. The additional - 2 db of attenuation required in' the second and third octave . bands could be obtained by lining approximately 10 ft of the 12 x 48 inch duct with 1-inch liner. However, as was pointed out above, the straight duct attenuation in line 2 is probably too conservative in these lower octave bands, hence the pack age unit would most likely provide a satisfactory treatment. other sound impervious layer such as metal or board. Stand ard reference books should be consulted for sound insulating properties of various materials. Inside lining material, used in the case previously mentioned, would serve as an absorber of the sound transmitted through the duct walls, and thus act as a means of preventing the transfer of noise into the air stream. Inside lining may also be used in ducts to absorb noise which reaches the air stream from equipment such as fans, sprays, and coils; noise due to eddying currents set up by elbows, dampers, and similar obstructions; and noise trans A calculation is now made of the acoustic power level gen erated by the grille itself. The face velocity of the grille is 1500 cfm/1.5 sq ft = 1000 fpm. From Fig; 8, assuming a vertical or horizontal bar deflection-type grille, the average power level in the speech interference bands (600-1200, 1200-2400, 2400 4800 epe) for a face velocity of 1000 fpm is 41 dbe per square foot of grille area or 41 + 10 log 1.5 * 43 dbe for the grille in this example. ` mitted from room to room in a common duct system. CONTROLLING VIBRATION FROM MACHINE MOUNTINGS It is impossible to select equipment which will operate with out producing some mechanical noise and, since the equip From line 10 of the calculation table the relative Lr in the speech interference bands (600-4S00 cps) is --20 db. Conse quently the Lm of the grille noise at 7 ft is 43 -- 20 = 23 db. This is well below the 30 db criterion selected for this room and therefore, is satisfactory. In reverberant fields all four grilles contribute so the total acoustic power level of the four grilles is 43 + 10 log 4 = 49 dbe. From line 13 of Table 9 the relative Lr is --26 db aod therefore the reverberant L9 will be 49 -- 26 or 23 db, which by coincidence is the same as that calculated at the 7-ft distance from one grille and, therefore, is also satisfactory. ' ment must be mounted in a building, it is probable that a part of this noise will be transmitted to the building to such a degree as to make noisy conditions in the rooms which are to be air conditioned. Much of this noise may be transmitted by the duct if it is rigidly connected to the fan outlet. It is common practice to malra the connection between the fan and the duct with a canvas sleeve which effectively restricts noise at this point. Noise may also enter the building through the mounting of the motor and the fan. Flexible mountings should be provided in The calculation of grille noise in this example was left to the end in order to keep a simple continuity to the principal ' problem of calculating the fan noise in the room. Experience shows that it is advantageous to calculate the grille noiso early in the problem as indicated in the outline given in the text so all installations,- but these mountings must be carefully de signed so that they will actually reduce the energy transmitted between the machinery and the supporting floor. If a flexible material is used, it is desirable to investigate the installation Sound Control so that it is not short-circuited by through bolts which are improperly insulated, and by electrical conduit which is not properly broken and is attached both to the equipment and to the building. The flexible mounting, if improperly en gineered, may actually increase the energy transmitted be tween the equipment and the supporting floor. In the proper isolation of vibration, which is usually in the lower range of frequencies and docs not include the airborne vibrations known as sound, there is one basic formula which is important in the solution of the problem. It is the formula of transmissibility as governed by the equation: 353 where T * transmissibility of the support. ' / frequency of the vibratory force. .. /. -- natural frequency of the machine unit on its support (damping -- 0). . Equation 27 shows that the transmissibility approaches unity for disturbing frequencies considerably lower than the natural frequency of the mounting. As the disturbing fre quency is increased, the transmissibility is also increased until at the resonant frequency, where / = /,, the transmissibility becomes infinite. This is not true in practice because all ma terials have some internal damping effect. However, operating at or very close to the resonant frequency is always serious as forces and stresses may be multiplied, 10 to 100 times. As the disturbing frequency becomes greater than the natural frequency, the transmissibility becomes a smaller quantity> and at the value of///, =* it again hasthe value of unity. Beyond this point tine isolation begins. At a ratio of 3 to 1 for / to /. the isolation is effective enough for practical appli cation, and experience and economical design have shown that a ratio of 5 to 1 is good. For high speeds, higher ratios for / to /. are easily attained and give better results for effective vibration control. For the lower speeds as experienced with compressor work the higher ratios become uneconomical At these lower speeds the imbalanced force goes down as the square of the speed ratio, so that it is quite practical to com promise and use a lower ratio of / to , say 2 or E to 1. For a given installation, the.speed of the compressor is fixed by the specifications; therefore the value of / is fixed. That leaves only/, to be determined, and that is accomplished by the choice of mounting material and design for the sup port of the machine. It is well to keep in mind that when trying to isolate vibration, no attempt should be made to iso late the driving and driven piece of equipment separately. The two should be mounted on a rigid frame, and then the entire assembly isolated according to the rules presented in this chapter. The value of /. can be controlled by the flexibility of the machine support, and when the deflection of the machine support is proportional to the load applied (such as with springs or nearly so with rubber-in-shear) the value of /, can be determined by Equation 28: (28) where ff = gravitational constant = 32.2 feet per (second) (sec . ond). Fig. 23 .... Static Deflection for Various Frequencies d static deflection of supporting material, feet. - /. " natural frequency of the machine unit on its support (damping * 0), cycles per second. - By the use of Equation 28 a'set of curves may be plotted as shown in Fig. 23. The first line AB, plotted as the critical' fre quencies for the various static deflections, is a curve showing the worst possible conditions or resonant conditions. . Plotting another curve CD, which is V^2 times curve AB, shows the area MCDN in which the resilient material or mounting does more harm than good. Plotting curves EF (3 times curve AB) and GH (5 times curve AB) shows area EGHF which represents efficient and economical isolation.Area GPOH is excellent isolation, but for all except the highest speeds, becomes rather uneconomical because of.the large deflections required. '. Example An electric motor driven compressor unit is to be isolated. The compressor is partially balanced and operates at a Bpeed of 360 rpm. The speed of the motor is 1160 rpm, and it is belt-connected to the compressor. Total weight of the com pressor and motor is 4500 lb. ' Solution: The minimum disturbing frequency to be isolated is 360 cycles per minute. Assume that the desired ratio of forced to natural frequency is 3 as a minimum, and that 5 is desired. The desired natural frequency of the mounting is 360 -v- 5 = 72 cycles per minute. From Fig. 23 a deflection of 7 in. is required to attain a natural frequency of 72 cycles per minute. This value may be obtained from critical curve AB for 72 cycles, or from curve GH (5 times critical) for 360 cycles. For a ratio of 3 the deflec tion would be 2.5 in. The next step is to determine the total weight to be sup - ported by the springs. Tor low speed partially balanced com pressors, it has been found necessary to add a foundation / weighing 2 to 3 times the weight of the motor and compressor, in order to maintain the machine movement below 0.03 in. Compressor and motor........................................... 4500 lb Concrete foundation......................... 9000 lb Total....................................................................... 13,500 lb Practical application dictates the number of springs to be used, which is based on the design of the machine foundation and the supporting floor structure. However, it is desirable to design for at least 8 springs and one or two spares for cases of unknown weights. As many as 50 springs have been used on one installation. The distribution of the springs must be bal anced against the masses to be supported. Otherwise the 354 CHAPTER 25 1959 Guide foundation design and supporting structure determine the location of the springs. . * The choice of the material used in the design of the resilient mounting is also important. For the slow-speed type com pressor, a common speed found in practice is 360 rpm. For speeds below this, isolation should not be attempted except under careful supervision. Referring to Fig. 23, it is found that for 360 rpm the static deflection required for a ratio of///,, of 3 to 1 (line EF) is 2.5 in., and for a ratio of 5 to 1 (line GH) it is 7 in. For these values of deflection the only choice of ma terial is the coil spring. This is *lwi true for speeds up to about 700 rpm. In consideration of the transverse spring constant (so as to maintain good ratios among the various degrees of freedom) experience has shown that the spring should be de signed with a tcorking height equal to 1.0 to 1.5 times the out side diameter. A long spring of small outside diameter him very low transverse rigidity, and therefore requires some additional means of preventing side drift of' the unit, *nH on very sensitive applications this may tend to destroy the illa tion efficiency. For speeds of 700 -to 1200 rpm the required deflections range from 0.22 in. to 0.80 in. For speeds of 700 to 1200 deflections range from 0-22 in- to 0.8 inch. For these con ditions springs or rubber-in-shear can be used. Special rubber is required if the isolators arelikely to be contaminated by oiL For speeds higher than 1200 rpm rubber-in-shear, as well as cork specially made for. vibration isolation, can be applied with good results. These limitations are by no means absolute, because certain liberties .may be taken without impairing the result if all posable degrees of freedom have been taken into account in the design of the installation. -. When a machine unit is properly isolated it will have a definite amount of movement which is determined by the ratio of the unbalanced forces to the total mass' of the mm-him* if this resultant machine movement is too great for the neces sary connections or the satisfaction of the customer, it can be reduced in' twoways only without'destreying the quality of the isolation'; first, adding mass or dead weight to the ma chine (such as concrete) common in the application of low speed, partially balanced machinery; second;- accurately bal ancing (both statically and dynamically), all moving. parts so as to eliminate the vibration at the source. -This lattermethod is the best engineering practice and is the modern trend. How ever, even with' well balanced machinery, installed in the vicinity of quiet offices, it is usually necessary to properly isolate the equipment to prevent the transmission of vibra tion likely to cause complaints. . - Where limitation of maz-hint, movement is desired during the starting and stopping periods, the application of friction or hydraulic Humping will serve without seriously interfering with the efficiency of the isolation. . .. REFERENCES 1 American Standard Acoustical Terminology (American Standards Association, Z24-1--1951). * Handbook of Noise Measurement (General Radio Company, Cambridge, Massachusetts). * 1S. S. Stevens:'The measurement of loudness (Journal Acoustical Society of America, Vol. 27, September 1955, p. 815). 4 American Standard Sound Level Meters for Measurement of Noise and Other Sounds (American Standards Association, Z24.3--1944). `L. L. Beranek: Noise criteria for office spaces (Journal Acoustical Society of America, Vol. 28, September 1956). * R. D. Madison and R. J. Wells: Fan noise (Handbook of Noise Control, ed. C. M. Harris, McGraw-Hill Book Co., New York, 1957). ' R. D. Madison (ed.): Pan Engineering (Buffalo Forge Company, Buffalo, New York, 1949, p. 313). * B. B. Daly: Noise Level in Pans (Institution of Heating and Ventilating Engineers Paper N6.H7V2S). ' I L. b. Beranek, G. W. Kampennan, and C. H. Allen: Noise of centrifugal fans (Journal Acoustical Society of America, Vol. 27, March 1955, p. 217). . 10 C. H. Allen: Noise from air-conditioning fans (Notse Con trol, Vol. 3, January 1957, p. 28). . II C. F. Peistrup and J. E..Wesler: Noise of ventilating fans (Journal Acoustical Society of America, Vol. 25, March 1953, p.322). ** J. B. Chaddock: Ceiling Air Diffuser Noise (Bolt Beranek and Newman, Inc., Cambridge, Massachusetts, Technical In formation Report No. 45, August 28, 1957). 11T. L. Moore, H. H. Bell, and J. K. Nunnely: Noise at tenuation in straight ventilation ducting (S. M. thesis, Massa chusetts Institute of Technology, June 1957). - . 14 D. A. Wilbur and F. R.'Simons: ASHVE Research Re port No. 1205--Determining sound attenuation in air condi tioning systems (ASHVE Transactions, Vol. 48,1942, p. 267). . * H. J. Sabine: The absorption of noise in ventilating ducts (Journal Acoustical Society, of America, Vol. 12, 1940, p. 53). . 11 For coefficients of commercial sound absorbent materials see Acoustical Materials Association Bulletin (Acoustical Ma terials Association, New York). ' '' 11 L. L. Beranek: Sound absorption in rectangular ducts (Journal Acoustical Society of America, Vol. 12, October 1940, p. 237). 11 P. M. Morse: The transmission of sound* inside pipes (Journal Acoustical Society of America, Vol. 11, October 1939, p. 205). . u R. J. Wells: Noise control problems in air conditioning equipment (Heating, Piping and Air Conditioning, Vol. 29, August 1957, p. 138). ... . * L. L. Beranek: Acoustics (McGraw-Hill Book Co., New York,.1954, Chapter.10). , . j p is CHAPTER 26 - STEAM HEATING SYSTEMS Classification of Steam Heating Systems by Types; One-prpe, Two-pipe, Subatmospherk and Orifice Systems;- Sizing Piping for Steam Heating Systems, Pressure-Reducing Vahesf Bailer Connections; Condensate Return Pumps; Vacuum Heating Pumps; Traps; Drips; Connections fo Heating Units; Control Valves . STEAM heating systems may be classified according to any one of, or combination of, the following features: (1) piping arrangement, (2) pressure or vacuum conditions obtained in operation, (3) method of returning condensate to the boiler. Classification by Piping Arrangement .- - A steam heating system is known as a one-pipe system when & single main serves the dual purpose of supplying steam to the heating unit and conveying condensate from it. Ordinarily, to each heating unit there .is but one connec tion which must serve as both the supply and the return, although separate supply and return connections may be used. A steam heating system is known as a two-pipe system when each beating unit is provided with two piping connec tions, and when steam and condensate flow in.separate mains and branches. . Heating systems may also be described as up-flow or down-flow, depending od the direction of steam flow in the risers; and as a dry-return or a wet-return, depending on whether the condensate mains are above or below the water line of the boiler or condensate receiver. . Classification by Pressure or Vacuum Conditions Steam heating systems may also be classified as high- pressure, low-pressure, vapor, and vacuum systems, depend ing on the pressure conditions under which the system is designed to operate. . - A system is known as a high-pressure system when the operating pressures employed are above 15 psig; as a low- pressure system when pressures vary from 0 to 15 psig; as a vapor system when the system operates under both vac uum and low-pressure conditions without theuse of a vac uum pump; and as a vacuum system when the system oper ates under vacuum and low-pressure conditions with the use of vacuum pump. . When automatic controls are employed to vary the pres sure conditions in the system in accordance with outside weather conditions, the system may be known as a sub- atmospheric, differential, or synchronized system. These latter classifications are proprietary designations. When orifices are employed on the inlets to the heating units the system may be known as an orifice system. Classification by Method of Returning Condensate When condensate is returned to the boiler by gravity, the system is known as a gravity return system. In this system all heating units must be elevated sufficiently above the wa ter line of the boiler, so that the condensate can flow freely to the boiler. Elevation of the heating units above the water line must therefore be sufficient to overcome pressure drops due to flow, as well as pressure differences due to operation. Referring to Fig. 1 it will be noted that the boiler and wet- retum form a U-shaped container, with the boiler steam pressure on the top of the water at one end, and the steam mam pressure on the top of the water at the other end. The difference between these two pressures is the pressure drop in the system, io., the friction and resistance to the flow of steam in passing from the boiler to the far end of the main, and the pressure reduction in consequence of the condensa tion occurring in the system. The water in the far end will rise sufficiently to overcome this difference in order to bal ance the pressures, and it will rise far enough to produce a flow through the return pipe and overcome the resistance of check valves, if instated. - - If a one-pipe steam system is designed, for example, for a total pressure drop of Vs psi/and utilizes a Hartford re turn connection inateAH of a check valve on the return, the rise in the water level at the far end of the return, due to the difference in steam pressure, would be Vs of 28 in. (28-in. head being equal to one pound per square inch), or 3Vs in. Adding 3 in. to overcome the resistance of the return main, and 6 in. as a factor of safety for heating up, gives 12^j in. as the distance the bottom of the lowest part of the steam main and all heating units must be above the boiler water line. The same system, however, installed and sized for a total pressure drop of Vs psi, and . with a check valve in the return, would require Vt of 28 in., or 14 in. for the differ ence in steam pressure, 3 in. for the flow through the re turn, 4 in. to operate the check valve, and 6 in. for a factor of safety, making a total of 27 in. as the required distance. Higher pressure drops would increase the distance accord ingly. ` When conditions are such that condensate cannot be re turned to the boiler by the action of gravity, and either traps or pumps must be employed, the system is known as a mechanical return system. There are-three, general types of 355 356 CHAPTER 26 1959 Guide mechanical condensate return devices in common use: (a) the alternating return trap, (6) the condensate return pump and (c) the vacuum return pump. In systems -where pressure conditions in the system vary between that of a gravity return and a forced return sys tem, a boiler return trap or alternating receiver is employed and the system may be known as an alternating return sys tem. ' When condensate is pumped to the boiler under pressures of the atmosphere or above, the system is known as a' con densate pump return system. '. When condensate is pumped to the boiler under vacuum conditions, the system is known as a vacuum return sys tem. In either the condensate or vacuum pump systems it is highly desirable to arrange for gravityflow to a receiver and to the. pump. The pump then forces condensate into the boiler against its pressure. ' ONE-PIPE SYSTEMS One-pipe 'systems, as previously defined, are systems in which steam and condensate flow in the same pipe. Radia tors and other heating units, in general, have only .one pip ing connection from main to unit, although it is possible to employ.two connections to the same main as indicated in Fig. 2. Unit heaters in one-pipe systems may also have sepa rate connections to the wet-return. - There are several variations in the piping arrangement of 1. Up-feed one-pipe systems where the radiators and other heating units are located above the supply mains. The mains in this instance convey both steam and condensate. Therefore, it is preferable to limit this design to systems with a connected load under 2500 sq ft EDR. Such a system is illustrated in Fig. 3. Typical connections to radiator or risers are illustrated in Figs. 4 and 5 and method of changing sites of rn&in* in Fig. 6. Branches from steam mains in one-pipe gravity steam systems should use the preferred connection shown in Fig. 7, but where radiator condensate does not flow back into the main, the acceptable method shown in the same figure may be used. This acceptable method has the advantage of giving a perfect swing joint when connected to the vertical riser or radiator connection, whereas the preferred connection does not give this swing without distorting the angle of the pipe. Runouts are usually made about 5 ft long to provide flexibility for movement in the main - 2. Up-feed one-pipe system with a connected load m excess of 1600 sq ft EDR, where radiators and other heating units are located above the mains, as illustrated tn Pig. 8. It will be noted that the mains are dripped at each riser connection to a wetretum, as indicated in Fig. 5, so that the m&in carry a mini mum of the condensation. This feature is always desirable in the design of any one-pipe steam system. Radiators immediately above the mains may be connected as shown in-Fig. 4. Upfeed systems are not recommended for systems high*? than four or five stories. 3. Down-feed one-pipe systems, where the radiators and other heating units are located below the supply main. In Rg. 4 .... Typical Steam Runout where Risers Are Not Dripped ' . Rg. 2.... Typical Two-Pipe Connections to Unit Heaters ' in One-Pipe Air-Vent Systems Rg. 5 Typical Steam Runout where Risers are Dripped rg. i BCCEHTOC (S3UCM* Rg. 6....Method of Changing Size of Steam Main when Runouts are Taken from Top Rg. 7 ACCEPTABLE PREFERRED .Methods of Taking Branch from Main Steam Heating Systems 357 Rg. 10____Typical Installation Using Condensate Pump arrangement only risers and connections to heating units convey both steam and condensate, and both are flowing in the same direction. The steam main is kept relatively free of condensate by dripping through the drop risers. Drain valves should be installed on all wet-return mains and on the return header at the boiler. ' -F.<wh radiator or hating unit in a one-pipe system must be supplied with a thermostatic sir valve which functions to relieve air from the heating unit under pressure, and to close when steam itself heats the thermostatic element of the valve. _. To improve steam circulation in one-pipe systems quick- vent air valves should be provided at the ends and at inter mediate points where the steam main is brought to a higher elevation, or where dropped below the water line.- It is de sirable to install the air-vent valves about a foot ahead of the drips, as indicated in Fig. 8, to prevent posable damage to their mechanisms by water. . ~" Air valves are of two general types, the pressure and the vacuum types. The pressure type permits the inflow of atmospheric air to the system when the steam pressure in the system falls below atmospheric pressure. The vacuum type, which contains a small check valve, prevents the air from flowing back to the system and thereby maintains vacuum conditions in the system, and a consequent evapora tion ' or generation of steam.or vapor at subatmospberic pressures, and at consequent lower temperatures. Systems which use vacuum - valves are known as vapor or vacuum one-pipe systems. The vapor or vacuum systems will main tain a more uniform temperature condition than the pres sure systems. Each heating unit in a one-pipe system may also be pro vided with a valve on the connection to the unit, although this is not essential except to shut the unit off when it is not desired for heating. Valves on one-pipe systems must be either fully opened or fully dosed. No throttling or modu lating position can be maintained, since, if a valve is par tially closed, condensate will not drain from the unit. This condition is dangerous because it may create a low water condition in the boiler with consequent burning or cracking of the boiler, or create a hazard due to the freezing of the waterlogged heating unit itself. TWO-PIPE SYSTEMS Two-pipe systems, as previously defined, are systems in which steam and condensate flow in separate pipes. Twopipe systems may operate under high-pressure, low-pressure, vapor, or vacuum conditions. Either the up-flow or the down-flow arrangement of mains may be employed. Two-Pipe High-Pressure Systems Two-pipe high-pressure systems operate at pressures above 15 peig, usually from 30 to 150 psig. They are usu ally used in large industrial buildings, which are equipped Proper piping connection* ore essentia! with ipeciaJ applhncsi for pressvre aquaCzing and air efiminctioo. Rg. 11.... Typical Up-Feed Two-Pipe System with Automatic Return Trap* I 358 CHAPTER 26 1959 Guide Rg. 12 .... Typical Down-Feed Two-Pipe System with unit heaters or large built-up fan units, or in which high-pressure steam is required for process work. fig. 9 illustrates a typical high-pressure system. Because of the high pressures and the great differential between steam and return mains, it is posable to locate returns above the heating units and lift the condensate to these returns. The condensate can be flashed into steam in low-pressure mains if any are available, or passed through an econo mizer heater before being discharged to a vented receiver. It is, of course, -necessary to provide for the elimination of air from high-pressure systems, just as in low-pressure sys tems. Return traps used on high-pressure systems are usually of the bucket, inverted-bucket, float, or impulse type. They are described in a later, section Steam Traps. Two-Pipe Low-Pressure Systems Low-pressure systems operate at pressures of 0 to 15 psig. The piping arrangement of both up-feed and downfeed low-pressure systems is identical with those of twopipe vapor systems described in the following section. The only difference between the two systems is in the type of air valve used. The air valves used in low-pressure systems usually do not contain the check discs and hence, the sys tem cannot operate under a vacuum. The low-pressure sys tems are not as popular as the vapor systems, because they Rg. 14....Typical Connections for Automatic Return Trap have the disadvantage of not holding heat when the rate of steam generation is diminishing They also have the dis advantage of corroding to a greater extent than vapor sys tems, due to the continued presence of new air in the system. Low-pressure systems have the advantage, however, of re turning condensate to the boiler readily and not retaining it in the piping, as may be possible in vapor systems when the system pressure exceeds the static head provided for the gravity return at the boiler. Fig. 10 illustrates the con version of a conventional gravity return system to a typical low-pressure system with a condensation pump. A check valve and a gate valve must always be installed between the pump discharge and the boiler. A check valve on the re ceiver vent will-prevent the backflow of air when the system is cooling down. Two-Pipe Vapor Systems Two-pipe vapor systems operate at pressures varying from 20-in. vacuum or more (depending upon the tightness with which the system is assembled) to 15 jw?g without the use of a vacuum pump. A typical two-pipe up-feed vapor sys tem is shown in Fig. 11, and a typical two-pipe down-feed system is illustrated in Fig. 12. The method of dripping drop BOTTOM OF STEAM DROP CATE FLOAT AND THERMOSTATIC TRAP ' DIRT POCKET. }---CONNECTED TO DRY RETURN (WHERE CONNECTED TO WET RETURN. OMIT TRAP) Rg. 13.... Detail of Drip Connections at Bottom of Down-Feed Steam Drop Rg. 15.... Typical Two-Pipe Vacuum Pump System Steam'Heating Systems 359 Two-Pipe Vacuum Systems Vacuum systems operate under conditions of both low pressure and vacuum, but employ the vacuum pump to insure maintenance of subatmospheric pressures in the re turn piping for all operating conditions. The pump thus assists the supply steam in overcoming the resistance of the system piping and insures rapid circulation and even heating. The system may operate transiently with subatmospheric pressure in the supply piping during the time the rate of steam generation is equivalent to or less than the total connected load. A typical two-pipe vacuum system is illustrated in Fig. 15. risers in a down-feed system is illustrated in Fig. 13. Radia tors discharge their condensate and air through thermostatic traps to the dry-return main. Air is eliminated, when the system is under pressure, at the ends of the supply and re turn mains just before they drop to the wet return. The vent valves are of the float rather than float and thermo static type since there should be no steam in the return main as long as the thermostatic traps on the radiators or convectors are operating properly. The float element of the valve closes the valve when, due to pressure differences, water rises to the point of overflow in the main. The vent valves are also provided with a small check Hisn which closes to prevent the inflow of air to the system when the pressure drops below atmospheric pressure^ -This enables the system to operate under vacuum conditions at lower steam temperatures for a period of four to eight hours, de pending on the tightness of the system. Vapor systems may also be provided with an automatic re turn trap or alternating receiver which automatically' re turns condensate to the boiler when the boiler is steaming under pressure conditions which would prevent the return of condensate by gravity. The typical connections for an automatic return trap are illustrated in Fig. 14. The two check valves are necessary for its successful operation. Each heating unit in a vapor system, as in all two-pipe systems, is provided with a graduated or modulating valve which permits the control of heat in the radiator by varying the opening of the valve. " Rg. 17.... Method of Constructing a lift in a Return Line The return risers are connected in the basement into a common return main which slopes downward toward the vacuum pump. The vacuum pump withdraws the air and water from the system, separates the air from the water and expels it to atmosphere, and pumps the water back to the boiler or other receiver, which may be a feed-water' heater or hot well. It is essential that no connection be made from the supply side to the return side at any point except through a trap. The return system should provide unre stricted gravity flow of the condensate and air to the pump receiver so that the. vacuum differential may be more uni formly applied throughout the return system. In some in stances, load conditions make it necessary to drop the return below the level of the vacuum pump inlet before this pump can be reached. This mm be taken care of when using a vac uum pump by installing a float controlled auxiliary accumu lator tank, pitted if necessary, just ahead of the vacuum pump inlet as shown by Fig. 16. The auxiliary tank as shown still permits an uninterrupted gravity flow from all return lines, but it does reduce the vacuum on the returns by 1-in. Hg for every foot of lift. The lift should be limited to 5 ft. .- Lifts should be avoided, but on individual mains near the end of the system a lift fitting may be employed. Fig. 17 shows a single-step lift, which may be used up to 5 ft of lift. When the lift is greater but does not exceed 8 ft, it should be divided into two lifts shown in Fig. 18. It is preferable 360 CHAPTER 26 1959 Guide to use commercial stock sizes of lift fittings, but if these are not available in the sizes required a satisfactory lift connec tion can be made from standard pipe fittings as shown by . Fig. 19. When a lift assembly requires a union, it should be installed in a horizontal run. The use of a lift in any part of the system results in slower heat-up as well as interrupted return of the condensate from the section ahead of the lift. Lift fittings should not be used in place of an auxiliary tank in the return main at the inlet'to the vacuum pump receiver. A condensate pump may be used as a mechanical lift where severe outlying lift conditions cannot be avoided. This may be piped into the system as shown by Fig. 20 in such a man ner as not to interfere with the normal functioning of the vacuum pump and without loss of vacuum on the returns preceding the condensate pump. TWO-PIPE SUBATMOSPHERIC SYSTEMS Subatmospheric systems are similar to vacuum systems but, in contrast, provide control of building temperature by variation of the beat output from the radiators. The radia tor heat emission is controlled by varying the pressure, tem perature, and specific volume of steam in circulation. These systems differ from the ordinary vacuum system in that they maintain a controllable partial vacuum on both the supply and return sides of the system, instead of only on the return tide. In the vacuum system, steam pressure above that of the atmosphere exists in the supply mains and radia tors practically at all times. In the subatmospheric system, atmospheric pressure or higher exists in the steam supply piping and radiators only during severe weather. Under average winter temperature the steam is under partial vac uum which in mild weather may reach as high as 25-in. Hg, after which further reduction in heat output is obtained by restricting the quantity of steam. The rate of steam supply is controlled by a valve in the steam main or by thermostatically controlling the rate of steam production in the boiler. The control valve may be of the automatic modulating or floating type governed thermo statically from selected control points in the building, or it may be a special pressure reducing valve which will maintain the desired subatmospheric pressures by continuous flow into the heating main. In some systems radiator supply valves include adjustable orifices, or are equipped with regu lating orifice plates. The sizes of orifices used are larger than for other types of orifice systems because, for equal radiator sizes, the volume flowing is larger. Orifices are omitted on some systems.. Radiator traps and drips are designed to operate at any pressure from 15 psig to 26-in. Hg. Steam for heating domestic hot water should be taken from the boiler header back of the control valve so that pressures sufficiently high for heating the water may be maintained on the heater. The subatmospheric method of Fig. 20.... Use of Condensate Pump as a Mechanical Lift heating can be used for the heating coils of ventilating and air-conditioning systems. The flexible control of heat output secured by this method materially reduces the required size of bypass around the heaters. Some applications of sub atmospheric systems are proprietary. TWO-PIPE ORIRCE SYSTEMS Orifice steam heating systems may have piping arrange ments identical with vacuum systems. Some of these omit the radiator thermostatic traps, but use thermostatic or combination float and thermostatic trap6 on all drip points. A return condensate pump with receiver vented to atmos phere, a return-fine vacuum pump, or a return trap, is generally used to return the condensate to the boiler or place of similar disposition, such as a feed-water heater or hot well. The heat emission from the radiators is controlled by varying the pressure differential maintained. The principle on which these systems operate is that the steam flow through an orifice will vary with square root of pressure drop when the ratio of the absolute pressures on the two sides of the orifice exceeds 58 percent. If the absolute pressure on the outlet side is less than 58 percent of the absolute pressure on the inlet side, no further increase in flow will be obtained as a result of the increased pressure difference. If an orifice is so designed in size as to exactly fill a radiator with 2 psig steam on one side and Vi psig on the other, the absolute pressure relation is 14.7 +0.25___ ______ 14.7 + M " 000 " 90 Per""1' If the steam pressure were dropped to V\ psig on the sup ply pipe, the pressure on each side of the orifice would be balanced and no steam flow would take place. From this it will be apparent that if an orifice of a given diameter will fill a given radiator with steam when there is a given pres sure on tile main, reducing this steam main pressure will permit filling various desired portions of the radiator down to the point where the main pressure equals the back pres sure in the radiator, provided the supply pipe pressures are closely controlled. If orifices are designed on a similar basis for a given system and proportioned to the beating capacity of the radiators they serve, all radiators will heat proportionately to the steam pressure. The range of pres sure variation is limited by the permissible noise level of the steam flowing under the pressure difference required for Steam Heating Systems TTigyimnm heat output. The control of the steam supply is obtained by a valve placed in the steam main to maintain a determined pressure, and by varying the vacuum in the return lines. The valves are frequently set manually from a remote location, guided by temperature indicating stations in the building; or thermostatically controlled from a ther mostat on the roof, which automatically measures the differ ential of outdoor and indoor temperatures. Since the range through which the pressures may be varied is usually from 0 to 4 psig, the control should be capable of maintaining close regulation of the desired space temperatures, particu larly in mild weather. A recommended orifice schedule is shown in Table 1. Some systems use orifices not only in radiator inlets, but also at different points in the steam supply piping for the purpose of hoianring the system to a greater extent. In this manner the difference between the initial, and terminal pressure in the steam main may be compensated to a great extent. For example, if the initial pressure is 3 psig and the pressure at the end of the main is 2 psig, an orifice could be used in each branch for the purpose of obtaining a more uniform pressure throughout the system. Such a provision may be particularly useful in this system for branches close to the boiler where the drop in the main has not yet been produced. Some orifice systems are proprietary. SIZING PIPING FOR STEAM HEATING SYSTEMS The functions of the piping system are the distribution of the steam, the return of the condensate, and, in systems where no local air vents are provided, the removal of the air. The distribution of the steam should be rapid, uniform, and without noise, and the release of air should be facili tated as much as possible, because an air bound system will not heat readily nor properly. In designing the piping arrangement, it is desirable to maintain equivalent resist ances in the supply and return piping to and from a radia tor. Arrangement of the piping so that the total distance from the boiler to the radiator is the same as the return piping distance from the heating unit back to the boiler, tends to obtain such a result. The condensate which collects in steam piping as well as in radiators must be drained to prevent interference with the ready flow of the steam and air. The effect of back pressure in the returns and excessive revaporization, such as occurs where condensate is released from pressures considerably higher than the vacuum or pres sure in the return, must be avoided. It is important that steam piping systems distribute steam not only at full design load, but during excess and partial loads. Usually the average winter steam demand is less than half of the demand at the design outdoor temperature. Moreover, in rapidly warming up a system even in moderate weather, the load on the steam main and returns may exceed the maximum operating load for severe weather, due to the necessity of raising the temperature of the metal in the sys tem to the steam temperature, and the building to the design indoor temperature. Investigations of the return of condensate have revealed that as high as 143 percent of the design condensation' rate may exist under conditions of ac tual operation. Expressed in gallons per minute per 1000 sq ft equivalent direct radiation the theoretical condensing rate of the system at the design indoor temperature is 0.5. During the warming-up period this value will approach 0.72 gpm. The piping design of a heating system is greatly influ enced by its operating characteristics. Heating systems do 361 Table 1 .... Orifice Capacities for Low-Pressure Steam Systems--Pounds per Hour Thk labia it botad on data from octoaf tests* Orifice Droseter 64th* of on Inch 6 in. Hg Oifferenf/cl Sin. Hg Differential 4in.Hg Diffarantial 7 4.5-5.8 4.0-5.3 8 5.8-7.3 5.3-6.8 9 7.3-9.0 6.8-8.3 10 9.0-11.0 8.3-10.0 11 11.0-13.0 10.0+2.0 12 . 13.0-15.5 13 15.5-18.0 14 18.0-20.8 15 20.8-23.5 16 23.5-28.5 12.0-14.3 14.3-16.5 16.5-19.0 19.0-21.5 21.5-24.3 17 26.5-29.8 ' 24.3-27.3 18 29.8-33.3 27.3-30.5 19 33.3-37.0 30.5-33.8 20 37.0-40.8 33.8-37.3 21 40.8-44.8 37.3-41.0 3.8-1.8 4.8-6.3 6.3-7.5 7.5-9.3 9.3-11.0 11.0-12.8 12.8-14.8 14.8-16.8 16.8-19.0 19.0-21.5 21.5-24.3 24.3-27.0 27.0-30.0 30.0-33.3 33.3-36.3 Orifice Droraete* 64tht of an Inch 2 in. Hg Diffarantiaf 1 in. Hg Differential Orific* Aiaa sq In. 7 8 9. 10 11 2.5-33 3.3-4.3 4.3-5.3 5.3-6.5 6.5-7.8 12 7.8-9-3 13 9.3-10.8 14 10.8-12.3 15 12.3-14.0 16 14.0-16.0 2.0-2.8 2.8-3.5 3.5-4.3 4.3-5.0 5.0-6.0 6.0-7.0 7.0-8.0 8.0-9.3 9.3-10.5 0.00940 0.01227 0.01553 0.01917 0.02320 0.02761 0.03241 0.03758 0.04314 0.04909 17 16.0-18.0 10.5-11.8 0.05542 18 18.0-20.0 11.8-13.0 0.06213 19 20.0-22.0 13.0-14.5 0.06922 20 22.0-24.5 14.5-16.0 0.07670 21 24.5-26.8 16.0-17.8 0.08456 SqU.--The ndiotor orifice pl&u* recommended ia this table in made of brass *tampin*s 0-023 ia. thick cujvebaped to be iaented in radiator valve uo- S. 8. Sanford and C. B. Sprengsr: Flow of ateam through orifices into radi ator* (ASHVE Tuaweactkjwb, Vol. J7, mi. p. 371). not operate under constant conditions, because conditions change continually, due to variation in load. As the system is being filled with steam, the pressures existing in various locations may be different from those which exist for ap preciable periods at otber locations, although at equilibrium conditions the pressures are approximately the same. In designing piping it is of particular importance to arrange the system to preclude trouble caused by such pressure dif ferences. The systems which readily release the air, permit uniform pressures to be attained in much shorter time in tervals than those which are sluggish. Results are given in Fig. 21. from investigations1 to determine the rate of con densate and air return from a two-pipe gravity heating sys tem. Variations in the steam pressure during the warming-up period, when the rate of air elimination and condensation is high, are clearly indicated in these curves. It is evident that the condensate flow during the initial warming-up period reaches a peak, which is greater than the constant condensing rate eventually reached when the pressure becomes uniform. Moreover, the peak condensing 362 CHAPTER 26 1959 Guide r KCSSU f ~\ or am cl HUH. -- wt MTt l7l 1 11 11N, UM one* / \T \ \ OAPSCD Ttt*-UIHWTM fig. 21.... Relation Between Elapsed Time, Steam Pressure, Condensate and Air Elimination- Rates rate is obtained when the system steam pressure is lower than that existing during a period of constant condensing rate. It will also be noted that the peak rate of air elimina tion does not coincide with the higher condensing rate. Steam How The rate of flow of dry steam, or steam with a small amount of water flowing in the same direction, is in ac cordance with the general laws of gas flow, and is a func tion of the length and diameter of the pipe, the density of the steam, and the pressure drop through the pipe. This rela tionship, developed by Unwin and later by Babcock, has been used for years as a means of determining steam flow through pipes. The new charts for weight-flow rate, pres sure drop, and velocity presented in this chapter take into account the Reynolds number and its effect on friction loss, two items which were not considered when using the Un win or Babcock formulas. The data presented in Figs. 22, 23, 24, 25, 26 and Table 5, in later sections of this chapter, are based bn the Moody Friction Factor where the absolute roughness of the internal pipe surface is that of new commercial steel or wrought iron. The Reynolds number, as expressed by Equation 9, Chap ter 4, is Ne. dVp n (1) where V m velocity of the steam, feet per second, d " internal diameter of the pipe, feet. p density of saturated steam at a specified saturation pressure, pounds per cubic foot. . ft " absolute viscosity, pounds per foot-second. Table 2.... Pressure Drops in Common Use for Sizing Steam Pipe* - (For Commanding Initial Stmam Pressures) Initial Shorn Pressure, Pag Pressure Drop Par IOO Ft, Pd Total Pressure Orop in Shea Supply Piping, Pa* Sub&tmos. or 1 vacuum return/ 0 1 2 5 10 15 30 50 100 150 2-4 oz 2 oz 2 os 4 oz 8 oz 1 psi 2 psi 2-5 psi 2-5 psi 2-10 psi 1-2 psi 1 os 1-4 os 8 os IX psi 3 psi 4 psi 5-10 psi 10-15 psi 15-25 psi 25-30 psi Equipment, control valves, ete., most be aeleeted on tbe tarsia of delivered The velocity is determined by the equation W V 3600 pA (2) where W =* given weight-flow rate, pounds per hour. A -- internal pipe area, square feet. . The values used for the absolute viscosity of saturated steam are those of Lieb, published in Combustion, Decem ber, 1940. The relative roughness of the internal pipe surface is obtained by dividing the absolute surface roughness by the internal pipe diameter. The values for absolute rough ness are those presented by L. F. Moody in Mechanical Engineering, Vol. 69, 1947, p. 1005, and appear in Table 1, Chapter 4. From the Reynolds number and relative rough ness, tiie friction factor / is obtained from the Moody Fric tion Factor Chart, fig. 4 of Chapter 4. The head loss in feet is given by the equation fLV ` 2gd (3) where / ~ friction factor. L " length of pipe (100 ft). g -- acceleration due to gravity, 32.174 feet per (second) (second). Table 3.... Comparative Capacity of Steam Lines at Various Pitches for Steam and Condensate Flowing in Opposite Directions* ` (Pitch of Pipo in inches par 10 Ft. Velocity in Ft par Seel Pitch of Pipe.. X X - 1 in. IM &*. 2 in. 3 in. 4 fat. S m. Pipe Size inches Copticr Max. Vef. CapocHr Max. Vef. CapocHr Max. Vol. CapocHr- Max. Vef. Copoe*ty Max. Vol. CapocHr Max. Vef. Cepoc< ity Max. VoL CapacHr Max. Vol. Capacity Expressed in Pounds per Hour X 6.3 12 7.6 14 9.3 18 10.1 19 10.6 20 11.5 21 11.9 22 12.3 23 1 11.5 12 13.2 15 15.8 17 17.5 20 18.8 22 20.8 23 22.0 25 22.6 26 IK 26.2 18 29.3 20 33.3 23 36.1 25 38.5 27 41.3 28 43.2 29 44.6 31 IK 35.7 18 39.8 21 45.3 23 49.1 25 52.3 27 56.0 28 58.7 30 60.7 31 2 59.0 19 65.9 20 74.9- 23 81.4 25 86.6 27 92.4 28 97.1 29 100.3 30 * From Tbs Amkhcab Soarrr or Hbattmo ajr> AiB-Coxcmomso Ejranrszas Research Laboratory. Steam Hearing Systems 363 The pressure drop in psi per 100 ft of pipe is pah aP - 144 (4) Pipe Sizes Tbe determination of pipe rises for a given load in steam heating depends' on the following principal factors: ' 1. The initial pressure and the total presure drop which may be allowed between the source of supply and at the end of tbe return system. 2. The maximum velocity of allowable for quiet and dependable operation of the system, taking into consideration the direction of condensate flow. 3. The equivalent length of the run from the boiler or source of supply to tbe farthest, heating unit. . 4. The direction of flow of the condensate, whether against or with tbe steam. Initial Pressure and Pressure Orop - Theoretically, there are several factors to be considered such as initial pressure and pressure required at the end of the line, but it is most important that: (1) the total pressure drop does not exceed the initial gage pressure of the system, and in actual practice it should never exceed one-hall of the initial gage pressure; (2) the pressure drop is not so great as to cause excessive velocities; (3) there is a constant initial pressure, except on systems specially designed for varying initial pressures, such as the subatmospheric, which normally operate under controlled partial vacuums, and orifice and vapor systems, which at times operate under such partial vacuums as may be obtained due to the condition of the fire; and (4) the rise in water due to pressure drop,does not ex ceed the difference in level, for gravity return systems, be tween the lowest point on the steam main, the heating units, or the dry-return, and the boiler water line. Table 2 lists pressure drops in common use with corre sponding initial steam pressures for rising steam piping; It is common practice to limit the total drop in the supply piping to approximately Vs of the initial pressure. The allow able pressure per 100 ft is thereby determined by the equiva lent length. Designers may utilize total pressure drops up to Vt the initial pressure when steam velocities and operating pressure requirements of the selected equipment will per mit. For initial pressures of 30 prig and higher many de signers prefer to size steam piping on the velocity method. The total pressure drop should never exceed one-half of the initial gage pressure when condensate is flowing in the same direction as the steam. Where the condensate must flow counter to the steam, the governing factor is the velocr ity permissible without interfering with the condensate flow. ASKAE Research Laboratory experiments limit tiri? to the capacities given in Table 3 for horizontal pipes at various grades. Maximum Velocity The capacity of a steam pipe in any part of a steam sys tem depends upon the quantity of condensate present, the direction in which the condensate is flowing, and the pres sure drop in the pipe. Where the quantity of condensate is limited and is flowing in the same direction as the steam, only the pressure drop need be considered. When the conden sate must flow against the steam, even in limited quantity, the velocity of the steam must not exceed limits above which the disturbance between the steam and the counter flowing water may produce objectionable sounds, such as w.ter hammer, or may result in the retention of water in Table A .... Length in Feet of Pipe to be Added to Actual Length of Run--Owing to fittings--To Obtain Equivalent Length length in Foot to ba Added to Run Size of Pipe inches Standard Elbow Side Outlet Tcab Cote Valve* Globe Valve* Vab!e` X 1.3 . 3 0.3 14 7 X 1.8 4 0.4 18 10 2.2 5 0.5 23 12 ix 3.0 6 0.6 29 15 ix 3.5 7 0.8 34 18 2 4.3 8 1.0 46 22 2X . 5.0 11 1.1 54 27 3 6.5 13 1.4 66 34 3X 4 5 6 8 - 10 12 14 ' 8 15 1.6 80 40 9 18 . 1-9 92 .45 11 22 2.2 112 56 13 27 2.8 136 67 17 35 3.7 180 92 21 45 4.6 230 112 27 53 5.5 270 132 30 63 6.4 310 152 * Valve in fan open poeitioo. b Value* fiven apply only to a tee used to divert the Sow in tbe main to the it riser. Rnmplw of length in feet of pipe to be added to actual leoftb of run. 1^*'ORIP ____ M-AST DRIP--iJbBAOIATOR ' Measured Lenxth - 132.0ft 4 in. Gate Valve - I.9ft M is. Elbow* - 35.0 ft Min. Tea - 36.0 ft . Equivalent -- 205.9 ft certain parts of the system until the steam flow is reduced sufficiently to permit the water to pass. The velocity at which such disturbances take place is a function of (1) the {ripe size, whether the pipe runs horizontally or vertically; (2) the pitch of the pipe if it runs horizontally; (3) the quantity of condensate flowing against the steam; and (4) freedom of the piping from water pockets which under cer tain conditions act as a restriction in pipe size. Reaming Important It is extremely important that the ends of all pipe be reamed or filed. This insures full pipe area and minimizes disturbance of the steam or condensate stream. Equivalent Length of Run All tables for the flow of steam in pipes, based on pres sure drop, must allow for the friction offered by the pipe, as well as for the additional resistance of the fittings and valves. These resistances generally are stated in terms of straight pipe; in other words, a certain fitting will produce a drop in pressure equivalent to the stated number of feet of straight run of. the same size of pipe. Table 4 gives the num ber of feet of straight pipe usually allowed for the more common types of fittings and valves. In all pipe sizing tables in this chapter the length of run refers to the equivalent length of run as distinguished from tbe actual length of pipe PRESSURE OROP-PSI PER IOO FT PRESSURE DROP-OUNCES PER SQ IN. PER 100 FT 364 CHAPTER 26 1959 Guide Bated on Moody Friction Factor where flow of condensate does net inWbff Am flow of doom. Rg. 22... - Basic Chart for Weight-Row Rate and Velocity of Steam in Schedule 40 Pipe Based on Saturation Pressure of 0 Psig (With Multiplier Charts for Obfaintnp Weight-Flow Rotes and Velocities at All Saturation Pressures Between 0 and 200 Prig) Steam Heating Systems Rg. 22 (Continued).... Velocity Multiplier Chart 365 Example of Use of Basic and Velocity Multiplier Charts. Given: a. Weight-Flow Kate = 6700 lb per hr. b. Initial Steam Pressure -* 100 psig. c. Pressure Drop = 11 psi per 100 ft. ' Find: . . Siee <Jf Schedule 40 pipe required. . Velocity of steam in pipe. Solution: The following steps are illustrated by the broken tine on Fig. 22: Step 1. Enter Fig. 22 at a weight-flow rate of 6700 lb per hr and move vertically to the horizontal line at 100 psig. Step i. Follow along inclined multiplier line (upward and to the left) to horizontal 0 psig line. The equivalent weight flow at 0 psig is about 2500 lb per hr. Step S. Follow the 2500 lb per hr line vertically until it inter sects the horizontal line at-11 psi per 100 ft pressure drop. The nominal pipe size is 2} in. The equivalent steam velocity at 0 psig is about 32,700 fpm. Step 4- To find the steam velocity at 100 psig, locate the value of 32,700 fpm on the ordinate of the velocity multiplier chart at 0 psig. ' Step 6. Move along the inclined multiplier line (downward and to the right) until it intersects the vertical 100 psig pres sure line. The velocity as read from the right (or left) scale is about 13,000 fpm. Note: The preceding Steps 1 to 5 would be rearranged or reversed if different data were given. Table 5....Weight Row Rate of Steam in Schedule 40 Pipe* at Initial Saturation Pressures of 3.5 and 12 Psig.bi0 (Weight Row Rata Expntsod m Pound* par Hoar) . ' Procure Drop--Pri Par 400 Ft in length - Note. Pipe Srza Indie* Kb Pri (1 ax) Sat. press, psig X Psi (2 ox) Sat. press, psig K Pri (4 ox) Sat. press prig. K Pri (8 or) Sat. press, psig X Pri (12 ox) Sat. prats, prig. 1 Pri Sat. press, prig 2 Pri Sot. press, prig 3.5 12 3.5-" 12 3.5 12 3.5 12 3.5 , 12 3.5 12 3.5 12 H l ik 1H 2 2H 3 3H 4 5 6 8 10 12 9 11 14 16 20 24 29 35, 36 43 42 50 60 73 17 21 26 31 37 46 54 66 68 82 81 95 114 137 36 45 53 66 78 96 111 138 140 170 162 200 232 280 56 70 84 100 120 147 174 210 218 ( 260 246 304 360 430 108 134 174 215 318 380 462 550 162 194 234 258 310 378 465 550 660 670 800 . 990 285 460 810 1218 336 540 960 1410 410 660 1160 1700 420 680 1190 1740 510 820 1430 2100 480 780 1380 2000 590 950 1670 2420 710 1150 1950 2950 850 1370 2400 3450 726 1200 1920 3900 800 1430 2300 4800 950 1680 2820 5570 1160 2100 3350 7000 1410 2440 3960 8100 1690 3000 4850 10,000 1980 3570 5700 11,400 2400 4250 7000 14,300 2450 4380 7200 14,500 3000 5250 8600 17,700 2880 5100 8400 16,500 3460 6100 10,000 20,500 4200 7500 11,900 24,000 4900 8600 14,200 29,500 7200 8800 10,200 12,600 15,000 18,200 21,000 26,000 26,200 32,000 30,000 37,000 42,700 52,000 11,400 13,700 16,500 19,500 23,400 28,400 33,000 40,000 41,000 49,500 48,000 57,500 67,800 81,000 " Baaed on Moody Friction Factor, where flow of condensate doea not inhibit the flaw of attain. The weight-flow rate# at 3.8 prig can be used to carer ret. press, from 1 to B psig, and tho retreat IS psig can be ased to cover sat. press-from 8 to (Sprig with an * The steam velocities corresponding to the weight-flow rates given in this table eon be found from the basic chart and velocity multiplier chart. Fig. (1 366 CHAPTER 26 1959 Guide in feet. The length of run is not usually known at the out set; hence, it may be necessary to assume some pipe size at the start. Such an assumption frequently is considerably in error, and a more common and practical method is to assume the length of run and to check this assumption after the pipes are sized. For this purpose the length of run usu ally is taken as double the actual length of pipe. BASIC CHART FOR STEAM PIPE SIZING Fig. 22 is the basic chart for determining the weight-flow rate and velocity of steam in Schedule 40 pipe for various values of pressure drop per 100 ft, based on zero psig saturated steam. By use of the multiplier charts it may be used at all saturation pressures between 0 and 200 psig. TABLES FOR PIPE SIZING FOR LOW-PRESSURE The basic chart, Fig. 22, can be used for siring pipe on low-pressure systems. The values in Table 5 which are taken from the bade chart provide a more rapid mpans of selecting pipe sizes for the various pressure drops listed and for systems operated at 3.5 and 12 psig. The weight-flow rates shown for 3.5 psig can be used for saturated pressures from 1 to 6 psig, and those shown for 12 psig can be used for saturated pressures from 8 to 16 psig with an error not exceeding. 8 percent. Both Fig. 22 and Table 5 are for use where the flow of Table 6.... Steam Pipe Capacities for Low-Pressure Systems (For Utm on One-Pip* System* or Two-Pip* Systems in which Condonsate Flows Agomst the Steam Flow) Thh (able b based on data developed through research investigafioas of the American Society of Heating and Air-Conditioning Engineers Capacity cn Pounds per Hour Two-Pip* System* On*-Pip Systems Coodemote flowing against steam Vertical Horizontal Supply riser* opfeed Radiator valves and vertical connection* Radiator and riser runout* A B C* D* F* H 8_ 6 1 14 9 11 lH 31 19 20 LH 48 27 38 2 97 49 72 2X 159 99 116 3 282 175 200 3M 387 288 286 4 511 425 ' 380 5 1,050 788 -- 6 1,800 1,400 __ 8 3,750 3,000 -- 10 7,000 6,700 -- 12 11,500 9,500 -- 16 22,000 19,000 -- _ 7 16 23 42 __ -- -- -- _ -- -- -- -- 7 7 16 16 23 42 65 119 186 278 545 -- -- -- -- NeU: Stcexn tt xa svetsce pimun of I pd| b used u * t--gf expedite*. * Do Dot am Column B far pressure drops of less Uns H pe> per 100 ft af equivalent run. Use Fi*. 32 or Table 6 instead. . b Do not use Column D for pressure drops of less than psi per 100 ft of equivalent run exsept on sixes l in. and over. Use Fi*. ** w Table S instead. * Pitch of borisootal runouts to risen and radiators should be net less than M in. per ft. Where this pitch cannot be obtained, ruzxmU over 8 ft in Length should be cme pipe sise iarxer than called for in this tabic. condensate does not inhibit the flow of steam. Columns B and C of Table 6 are for cases where steam and condensate flow in opposite directions as in risers or runouts that are not dripped. Columns D, E, and F are for one-pipe systems and include risers, radiator valves and vertical connections, - and radiator and riser runout sizes, all of which are based on the critical velocities of the steam to permit the counterflow of condensate without noise. Return piping may be sized with the aid of Table 7, where pipe capacities for wet, dry, and vacuum return lines are shown for several values of pressure drop per 100 ft of equivalent length. It iscustomary to use the some pressure drop on both the steam and return sides of a system. Example t: What pressure drop should be used for the steam piping of a system if the measured length of the longest run is 500 ft, and the initial pressure is not to be over 2 psig? Solution: It will be asumed, if the measured length of the longest run is 500 ft, that when the allowance for fittings is added, the equivalent length of run will not exceed 1000 ft. Then, with the pressure drop not over one-half of-the initial pressure, the drop could be 1 psi or les. With a pressure drop of 1 psi and a length of run of 1000 ft, the drop, per 100 ft would be 0.1 psi, while if the total drop were 05 psi, the drop per 100 ft would be 055 psi. In both cases the pipe could be sized for a desired capacity according to the 0.1 and 055 pres sure drop lines in Fig. 22. On completion of the sizing, 'the drop could be checked by taking the longest line and actually calculating the equivalent length of run from the pipe sizes de termined. If the calculated drop is less than that assumed, the pipe size is all right; if it is more, it is probable that there are an unusual number of fittings involved, and either the lines must be straightened or the column for the next lower drop must be used, and the lines resized. Ordinarily, resizing will be un necessary. CHARTS FOR SIZING PIPE FOR HIGH-PRESSURE Many installations of heating systems for large industrial- type buildings have been designed for the use of high-pres sure steam, that is, without the use of pressure-reducing valves. Such systems usually involve the use of unit heaters or large built-up fan units with blast heating coils. Pressures on these systems vary from 30 to 150 psi. Temperatures are controlled by a modulating- or throttling-type thermostatic valve controlled by the air temperature in the room, fan inlet, or fan outlet. - Figs. 23, 24, 25, and 26 provide charts for sizing steam piping for systems of 30, 50, 100, and 150 psig at various pressure drops. These charts are based on the Moody Fric tion Factor, which takes into account the Reynolds number and the roughness of the internal pipe surfaces, and contain the same information as the basic chart of Fig. 22 but in a more convenient form. Return pipe capacities given in Tables 8 and 9 are based on the following assumed pressures in the return piping: Pressure Drop lb/100 Ft X x H H 2 - Pibisui* m Return tin* (Prig) 30 psi System 150 ps> System X IK l 2K 25 3 7K 4 10 20 The pressure loss and lice loss as given were substituted in the Babcock steam flow formula, and the resulting capac ity was multiplied by 12 for 30-psig systems and by 16 for Steam Heating Systems 367 Table 7.... Return Main and Riser Capacities for Low-Pressure Systems--Pounds per Hour (Reference to this tabfe wSt b* marie by column letter G through Y) This table b based on pipe n'ze data developed through the research investigation* of The American Society of Heating and Air-Conditioning Engineer* Table 8....Return Pipe Capacities for 30' Psig Steam Systems* Capacity Expressed in Pound* per Hoar Pipe Size K l iK m 2 2M 3 3K' 4 5 6 Drop Pressure--Pound* per 100 Ft a lenglh XXXX 1 115 170 245 308 365 230 340 490 615 730 485 710 1,025 1,290 1,530 790 1,160 1,670 2,100 2,500 1,580 2,650 4,850 7,200 2,360 3,900 7,100 10,600 3,400 5,600 10,300 15,300 4,300 7,100 12,900 19,200 5,050 8,400 15,300 22,800 10,200 15,000 21,600 27,000 32,300 19,000 27,800 40,300 55,500 60,000 31,000 45,500 65,500 83,000 98,000 * NoU: The above table is based an steam et pressures of 0 150-prig systems to obtain the values given in Tables 8 and 9. The return-line pressures used were found by observation of operating systems. The Babcock formula was used in this case since information on condensate flow in return lines based on the Moody Friction Factor is not readily available. SIZING PIPING FOR ONE-PIPE GRAVITY SYSTEMS Gravity one-pipe air-vent systems, in which the equivalent length of run does not exceed 200 ft, should be sized by means of Tables 5,6, and 7 and Tig. 22 as follows: ' 1. For the steam main and dripped runouts to risers where the Table 9.... Return Pipe Capacities for ISO Psig Steam Systems* Capacity Expressed h Pound* per Hour rj? Prop m Pressure--Pe per 100 Ft tit length XxXH 2 H 156 232 360 465 560 890 313 462 690 910 1,120 1,780 IK 650 960 1,500 1,950 2,330 3,700 IX 1,070 1,580 2,460 3,160 3,800 6,100 2 2,160 3,300 4,950 6.400 7,700 12,300 2K 3,600 5,350 8,200 10,700 12,800 20,400 3 6,500 9,600 15,000 19,500 23,300 37,200 3K 9,600 14,400 22,300 28,700 34,500 55,000 4 13,700 20,500 31,600 40,500 49,200 78,500 5 25,600 38,100 58,500 76,000 91,500 146,000 6 42,000 62,500 96,000 125,000 150,000 238,000 Nett: The above table is based on steam et pressure* at 1 to 80 pdf. steam and condensate flow in the same direction, use He psi drop (Table 5 or Fig. 22). 2. Where the riser runouts are not dnpperf.&nd the steam and condensate flow in opposite directions, and also for the radiator runouts where the same condition occurs, use Table 6, Column F. 3. For up-feed steam risers carrying condensate back from the radiators, use Table 6, Column D. 4. For down-feed systems, the main risers of which do not carry any radiator condensate, use Table 6, Column B. 5. For the radiator valve size and the stub connection, use Table 6, Column E. 6. For the dry-return main, use Table 7, Column O.' 7. For the wet-return main, use Table 7, Column N. 368 CHAPTER 26 1959 Guide Steam Heating Systems 369 Sated ob Mood/ Friction Factor whore Sow of condentato does not inhibit the flow of (team. Rg. 23.... Chart for Weight-Row Rate and Velocity of Steam in Schedule 40 Pipe Based on Saturation Pressure of 30 Pag . {May be Used for Steam Pressuret from 23 to 37 Pag with an Error Not Exceeding 6 Percent) - 40 o ioo o 400 eOo iooo tooo 4000 oooo to,ooo 20,000 WEIGHT FLOW RATE -POUNDS PER HOUR setboo looTooo Based on Moody Friction Factor where flow of condensate does not inhibit the flow of steam. Rg. 25.... Chart for-Weight-Row Rate and Velocity of Steam in Schedule 40 Pipe Based on Saturation Pressure of 100 Psig {May Be Used for Steam Pressures from 85 to 125 Psig With an Error Not Exceeding 8 Percent) Sated on Moody Friction Factor where flow of condensate does not inhibit the flow of steam. fig. 24 .... Chart for Weight-Flow Rate and Velocity of Steam in Schedule 40 Pipe Based on Saturation Pressure of 50 Psig (May Be Used for Steam Pressures from 40 to 60 Psig With an Error Not Exceeding 0 Percent) Rg. 26 .... Chart for Weight-Flow Rate and Velocity of Steam in Schedule 40 Pipe Based on Saturation Pressure of 150 Psig (May Be Used for Steam Pressures from 127 to 780 Psig With on Error Not Exceeding 6 Percent) 370 CHAPTER 26 1959 Guide On systems exceeding an equivalent length of 200 ft, it is suggested that the total drop be not over H psi. The return piping sizes should correspond with the drop used on the steam side of the system. Thus, where H* psi drop is being used, the steam main and dripped runouts would be sized &om Fig. 22; radiator runouts and undripped riser runouts from Table 6, Column F\ up-feed risers from Column D\ the main riser on a down-feed system from Fig. 22 (it will be noted that if Column E is used the drop would exceed the Kmit of H* P^i); the dry-retum from Table 7, Column L; and the wet-return from Column K. With a Hz psi drop the sizing would be the same for as H* psi, except that the steam main and dripped runouts would be sized from Fig. 22, the main riser on a down-feed system from Fig. 22, the dry-return from Column 7, and the wetreturn from Column H. Notes on Gravity One-Pipe Air-Vent Systems 1. Pitch of m*in should not be less than H in. in 10 ft. 2. Pitch of horizontal runouts to risers and radiators should not be lees than H in. per foot. Where this pitch cannot be ob tained, runouts over 8 ft in length should be one size larger than called for in the table. 3. In general, it is not desirable to have a main less than2 in. The diameter of the far end of the supply main should not be less than half its diameter at its largest part. ' 4. Supply mains, runouts to risers, or risers, should be drip ped where necessary. - 5. Where supply mains are decreased in'size they should be dripped, or be provided-with eccentric couplings, flush on bot tom. . Example 3: Size the one-pipe gravity steam system shown in Fig.' 27 assuming that this is all there is to the system, or that the riser and main shown involve the longest run on the system. Solution: The total length of run actually shown is 213 ft. If the equivalent length of run is taken at double this, it will amount to 430 ft. and with a total drop of H psi the drop per 100 ft will be slightly less than Ha psi. It would be well in this case to use Hz psi, and this would result in the theoretical sizes Fig. 27.... Riser, Supply Mam and Return Main of One-Pipe System Table 10....Pipe Sizes for One-Pipe Up-Feed System Shown in Fig. 27 Port of Sfttea Section of Pipe ipdiuhuu Sapplieri EDS Sq Ft Tfeo-' refjcnf Pipe Size (Isdws) Practical Pipe aze (ImAw) Branches to radiators... 100 2 2 Branches to radiators... 50 1H 1H Riser.................................... A to B 200 2 2 Riser.................................... B to C 300 2H 2H Riser.................................... C U> D 400 2M 2H Riser.................................... D to E 500 3 3 Riser.................................... B to F 600 3 3 Runout to riser................ F to G 600 3H 3M Supply main..................... G to H 600 3 3 BraDch to supply main.. H to J 600 2H 3 Dry return main............. F to K 600 1H 2- Wet return main............. K to M 600 1 2 Wet return main............. M to N 600 1 2 Wet return main............. N to P 600 1 2 indicated in Table 10. These theoretical sizes, however, should . be modified by using a wet-return not less than 2 in., while the m&insupply, G-H, if from the uptake of a boiler, should be made the full size of the main, or 3 in. Also the portion of the main K-M should be made 2 in. if tbe wet-return is made 2 in. SIZING PIPING FOR ONE-PIPE VAPOR SYSTEMS Piping for one-pipe vapor systems is sized so as to permit only a few ounces pressure drop in the system. Otherwise, the method follows that outlined for sizing one-pipe gravity systems. SIZING PIPING FOR TWO-PIPE HIGH-PRESSURE SYSTEMS Steam supply piping for two-pipe high pressure can be sized for greater pressure drops than that of the return piping. For a system using steam at 30 prig, the total pressure drop can be 5 to 10 psi, and for 150 psig systems, 25 to 30 psi. It has been observed that the maximum total pressure in the returns of a 30 psig system is about 5 psig, and that of a 150 psig system is about 20 psig. The pressure in the return mains is caused by the discharge of traps and flashing of con densate into steam because the return-line pressure is below that, corresponding to the saturation temperature of the con densate. The usual practice in the sizing of high-pressure re turns has been to size on the basis of H psi Pr 100 ft of pipe for 30 psig systems, and 1 psi per 100 ft for 150 psig systems. This is an average figure which corresponds generally to sev eral of the previously published tables for the design of highpressure return piping. Notes on Two-Pipe High-Pressure Systems Pitch of mains should not be less than H in. in 10 ft. Pitch of horizontal runouts to risers and heating units should not be less than H per ft. . SIZING PIPING FOR TWO-PIPE LOW-PRESSURE SYSTEMS Piping for two-pipe low-pressure systems is sized in the sama manner as for two-pipe vapor systems, except that the Steam Heating Systems 371 pressure drop throughout the system can be based on H psi to 1 psi drop. . SIZING PIPING FOR TWO-PIPE VAPOR SYSTEMS While many manufacturers of patented vapor heating ac cessories have their own schedules for pipe sizing, an inspec tion of these siring tables indicates that in general as small a drop as possible is recommended. The reasons for this are: (1) to have the condensate return to the boiler by gravity; (2) to obtain a more uniform distribution of steam throughout the system, especially when it is desirable to carry a moderate or low fire; and (3) to prevent large variations in pressure which would nullify the value of graduated valves on radia tors. For small vapor systems when the equivalent length of run does not exceed 200 ft, it is recommended that the main, and any runouts to risers that may be dripped, should be sized for about He psi drop per 100 ft, using Fig. 22 or Table 5, while riser runouts not dripped and radiator runouts should be ob tained from Column C, Table 6. The up-feed steam risers should be taken from Column B. For returns use Table 7, Column O, the upper portion for mains and the lower portion for risers. It should again be noted that the pressure drop in the steam ride of the system is kept the same as on the return ride, except where the flow in the riser is concerned. On a down-feed system, tire main vertical riser should be sized from Table 6, Column B, but the down-feed risers can be taken from Fig. 22 or Table 5 using a H psi drop. For vapor systems over 200 ft of equivalent length the drop should not exoeed H to H psi if possible. Thus, for a 400-ft equivalent run tire drop should be not over H* psi per 100 ft. In this case the steam mains would be rizcd-from Fig. 22, the radiator and undripped riser runouts from Table 6, Col umn C; and the risers from Fig. 22 because Column B gives a drop in excess of Hz psi. On a down-feed system. Fig. 22 would have to be used for both the main riser and the smaller riser feeding tire radiators in order not to increase the drop one Hz psi. The return risers would be sized from the upper portion of the same column, while any wet-returns used would be sized from Column 7. The same pressure drop is applied on both the steam and return sides of the system. Notes on Vapor Systems . 1. Pitch of mains should not be less than H hr- in 10 ft. 2. Pitch of horizontal runoutg.to risers and radiators should not be less than H hr* per ft. Where this pitch cannot be ob tained, runouts over 8 ft in length should be one size larger than called for in the table. 3. It is not desirable to have a supply main smaller than 2 in. 4. When necessary, supply main, supply risers, or runouts to supply risers should be dripped separately into a wet-return, or may be connected into the dry-return through a thermostatic drip trap. SIZING PIPING FOR TWO-PIPE VACUUM SYSTEMS Vacuum, atmospheric, subatmospheric, and orifice systems are usually employed in large installations and have total drops varying from H to 2 psi. Systems in which the maxi mum equivalent length does not exceed 200 ft preferably employ the smaller pressure drop, while systems over 200-ft equivalent length of run, more frequently are designed for the higher drop, owing to the relatively greater saving in pipe sizes. For example, a system with 2400-ft longest equivalent length of run could be designed for a pressure drop per 100 ft of 1 psi divided by 12, or H psi.1 this case the steam main would be sized from Fig. 22, and the risers also from Fig. 22 (Column B, Table 6, could be used as far as critical velocity is concerned, but the drop would exceed tire limit of H psi). Kiser runouts, if dripped, would also be obtained from Fig. 22 but if undripped, from Column C, Table 6. Pipe sizes for other parts would be obtained as follows: radiator runouts from Column C; return risers from lower part of Column S, Table 7; and return runouts to radiators--one pipe size larger than the radiator trap connections. Notes on Vacuum Systems 1. Pitch of mains should not be less than 14 in. in 10 ft. 2. Pitch of horizontal runouts to risers and radiators should not be less than Vi in. per ft. Where this pitch cannot be ob tained,. runouts over 8 ft in length should be one size larger than called for in the table. 3. In general, it is not considered desirable to have a supply smaller than 2 in. 4. When necessary, the supply main, supply riser, or runout to 8 supply riser should be dripped separately through a trap into the vacuum return. A connection riiould not be made be tween the steam and return sides of a vacuum system without interposing a trap-to prevent the steam from entering the re turn line. 5. Lifts should be avoided if possible, but when they cannot be eliminated they should be made in the manner described in thin chapter. 6. No lifts can be used in orifice and atmospheric systems. SIZING PIPING FOR INDIRECT HEATING UNITS Pipe connections and mains for indirect heating unite are sized according to the quantity of steam condensed by each unit. The condensate per unit depends upon the entering temperature and the air velocity, and may be obtained from manufacturers' rating tables. Where two or more units are placed in series, the entering air temperature for any unit 'will be the leaving temperature for the preceding unit. When the amount of condensate h*s been obtained for each unit, the pipe sizes should be based on the length of run and the pressure drop desired, as in the case of radiators. It is generally desirable to place the indirect heating units on a separate piping system rather than to connect them to the piping which supplies direct radiation. For type of connections see section on Connections to Heating Units. . PRESSURE-REDUCING VALVES While the illustrations of steam systems in this chapter indicate that they are supplied by separate boiler plants, it is also possible to have steam-supplied by a remote boiler plant or by a district heating system at pressures higher than desired for the equipment served. District heating is discussed in Chapter 27. There are certain fundamental principles that should be followed in the design of a building heating system which is to be supplied from district steam mains. Some of these are peculiar to district heating and some, although they may apply to any building, have been demonstrated to be par ticularly important when district steam is used. District heating companies have certain regulations regarding the consumer's installation to safeguard the mutual interest of supplier and consumer and to insure satisfactory and eco nomical service. When an installation is designed, local regulations and code requirements should be ohserved. Where steam is supplied from a boiler delivering steam at pressures higher than required for the heating system,one or more pressure-reducing valves (pressure regulators) are required. These are used in two classes of service, one S' 372 CHAPTER 26 1959 Guide where the steam must be shut off tight to prevent build-up of pressure on the low-pressure side at tame of no load, and the other where the low-pressure lines will condense enough steam to prevent build-up of pressure due to normal leakage through the valve. In the first case single-seated valves, either direct-operated or pilot-controlled, should be used and in the latter case double-seated valves, either direct-operated or pilot-controlled, may be used. Valves available are directoperated, spring, weight, air-loaded, or pilot-controlled, us ing either, the flowing steam or auxiliary air or water as the operating medium. The direct-operated, double-seated valve is less affected by varying inlet steam pressure than the di rect-operated, single-seated valve. Pilot-controlled valves, either single- or double-seated, tend to eliminate the effect of variable inlet pressures. 2. Sorrko rehw 3. Ptwwra-ndwins vohw 4. Pilot . 5. fabnw Cm . ' 6. ftwwt-figiifafag rc/ro . 7. Safety roDof vo/ye . 8. ttoGof vafv* dtschorg* to outMo 9. Bypass, on* dzo smattor Aon prosmro-tododag va/va Note: AO fitting* should b* Aumiiujii Standard Oo* 250 cod ironond/or SOOOxtorf. ({hod Wboto High-Prostuto Stoaa ii SoppOod for lo*>P(Wwr tuonwMhJ Rg. 28.... Two-Stage Pressure-Reducing and Pressure Regulating Equipment to the initial pressure, should be installed on the low-pres sure side. This should be ahead of the shut-off valve because the reducing valve can be more accurately and conveniently adjusted with the shut-off valve closed. A similar gage should be installed downstream from the shut-off valve for use during manual operation. Strainers should be installed on the inlet of the primary pressure-reducing valve and are also desirable before the second-stage reduction if there is considerable piping be tween the two stages. If a two-stage reduction is made, it is well to install a pressure gage immediately before the re ducing valve of the second-stage reduction for use in setting and flhfy.lting the operation of the first valve. In all cases it is advisable to install a drip trap between the two reducing valves. . Safety valves located on the low-pressure side should be set at least 5 psi higher than the reduced pressure where the reduced pressure is under 35 psig and at least 10 pri higher than the reduced pressure if the reduced pressure is above 35 pKig or is the first-stage reduction of a double reduction. A safety valve or valves, installed on the low-pressure side of a reducing .valve or valves, should be of sufficient capacity and should be set to relieve the entire output of the reduc ing valves in the event pressure on the equipment exceeds the low-pressure setting by the values indicated above. The outlet from relief valves should be piped to a location where the discharge to atmosphere cannot jeopardize persons or. property.* (See Figs. 28 and 29.) Topical service connections are shown in Fig. 30 for low- Valves that shut off all steam are called dead end type. They are single-seated, and some of them have pilot opera tion or constant air loaders that provide close control of the reduced pressure. If a thermostatically controlled valve is installed after, and near, a reducing valve in such a manner ' as to'cut off tiie passage of steam, the dead end type of re ducing valve should be used and a suitable trap should be installed to provide for drainage of condensate formed be tween the reducing valve and the control valve. If a onestage reduction is desired, it is necessary to use either a pilotcontrolled or an air-loaded direct-operated pressure-reducing valve where low pressures are to be maintained closely. Installation The installation of pressure-reducing valves in pipe lines requires detailed planning. They should be installed to give ease of access for inspection and repair. There should be a bypass around each reducing valve of area equal to the area of the redudng-valve seat ring. The globe valve in a bypass line should be of a good type of construction, and must shut off absolutely tight. A steam pressure gage, graduated up 1. S*rv>c* pipm from ctistrid doom mato 2. Motorized pilot on pra*wr*-raguta(ing vaf** 3. Budcct (rap on boador drip lint Noto; Wher* procan *qmpmMf i* mdiridvalty controttod, tenperator* control on hoodor may bo omittod. AO fitting! dioM b* American Standard Ctoo 250 cad iron or 300 fb stool in both rodoetioa and regtrfatfoa as semblies. Rg. 29 .... Steam Supply Installation with Header ' for Process and Zone Connections Steam Heating Systems 373 pressure sendee and Fig. 31 for high-pressure service. The district heating industry refers to valves according to their functional use. The pressure-reducing valve reduces pres sure to a safe point, and the pressure-regulating valve regu lates pressure to that required by equipment served. Fig. 31 illustrate the use of a pressure-regulating valve with a by pass. This bypass permits the operation of the system in AaM of failure in the pressure-regulating valve. In the smaller sizes, the bypass is sometimes omitted. When serv icing is required, the pressure-regulating valve can be re moved, a filler installed, and the inlet stop valves used for manual regulation of the pressure until repairs are made, fig. 29 shows a typical service installation with a separate line to the various heating zones and process equipment. If the initial pressure is below 50 psig the first stage pressure- reducing valve may be omitted. In Assembly A, Fig. 29, the single-stage pressure-reducing valve is also the pressure regulating valve. ' If the radiation served is of cast iron and the inlet pressure exceeds 50 psig, the ASME Code* requires the installation of pressure-relief valves where the inlet pressure exceeds the safe working pressure of the steam-using equipment, except where two reducing valves are installed in series and both are set at or below the safe working pressure of the equipment serviced. This, however, is not two-stage reduc tion. See Fig. 31. Two reducing valves, installed in series and both set at or below the safe working of the equipment serviced, introduce a source of safety while taking advantage of the more stable and satisfactory control provided by a single-step reduc tion. As can be seen from Fig. 31, the second valve which is set for a slightly higher reduced pressure is normally wide open and only comes into play to throttle the flow of high- pressure steam resulting from any failure of the primary valve. The increase of the system pressure to the higher pressure of the second valve is a signal that the primary- valve requires maintenance. With bypasses as illustrated. 1. Sorrieo pipe from district doom man 2. S*n*ce voire 3. Operating valve t 4. Manvel bypan 5. Pr*irre-regulcfing valve 6. Pitot 7. Balance or impulse lino. Follow tnomrioctaiei'i recomaendalioa. the primary valve can be serviced without shutting down the system. Since the valves are not both operating at the same time the distance between the valves is not critical. When making a two-stage reduction, eg., 150 to 50 psig and then 50 to 2 psig, allowance for expansion of steam on the low-pressure side of each reducing valve should be made by increasing the pipe area to approximately double the area of a pipe of the size of the reducing valve. This also allows steam flow to be at a more nearly uniform velocity. Separating the valves by a distance of at least 20 ft is recommended to reduce excessive hunting action of the first valve. Fig. 28 shows a typical double-reduction installation where - the pressure in the-district steam main is higher than can safely be applied to building heating systems. The first or ' ' pressure-reducing valve effects the initial pressure reduction. The pressure-regulating valve regulates the steam to the de sired final pressure. Pilot-controlled or air-loaded direct-operated reducing valves may be used without limitation for all reduced pres sure settings for all heating, process, laundry, hot water, etc. services. Spring-loaded direct-operated valves may be used for reduced pressures up to 50 psig providing they can pass the required steam flow without excessive deviation in re duced pressure. Weight-loaded valves are used for reduced pressures be low 15 psig and for moderate steam flows. Pressure-equalizing or impulse lines must be properly connected to serve the type of valve selected. For directoperated diaphragm valves with rubber-like diaphragms, the impulse line should be connected into the bottom of the reduced-pressure steam line-to allow maximum condensate to exist on the diaphragm and in the impulse or equalizing line or, if connected to the top of the steam line, a condensate accumulator should be used to reduce variations in the head of condensate on the diaphragm. Equalizing or impulse lines for pilot-controlled and direct-operated reducing valves em ploying metal diaphragms should be connected into the expanded outlet piping approximately 2 to 4 ft from the reducing valve and pitched away from the reducing valve to prevent accumulation of condensate. Pressure impulse lines for externally pilot-controlled reducing valves employing compressed air or fresh water should be installed in accord ance with manufacturer's recommendations. Selection of Valve Size Fig. 30.... Pressure-Regulating Valve with Bypass for Low Pressure Service Pressure-regulating valves should be sized to supply ade quately the maximum steam requirements of the heating 374 CHAPTER 26 1959 Guide Table 11 ....Suggested Capacity of Pressure-Regulating Valves and Traps !jrp of Coctrot Pnsm-IbgtMnp Yafrrm Capacity Ib/lHiilSq Ft DM Continuous or modulating operation, in termittent with on periods over 3 hr in duration Intermittent operation with on periods of H to 3 hr in duration H H' riods. To overcome this condition, two reducing valves are installed in parallel, with the sizes selected on a 70 and 30 percent proportion of maximum flow. For example, if 10,000 lb of steam per hour are required, the size of one valve is on the basis of 7000 lb, and the other on the basis of 3000 lb. During mild weather (spring and fall) the larger valve is set for slightly lower reduced pressure than the-smaller one and hence remains closed as long as the smaller can supply the demand. During the remainder of the heating season the valve settings are reversed to keep the smaller one closed except when the larger is unable to supply the demand. Intermittent operation with on periods of X hr or less Hh * One morfl foot EDB -- 240 Btu per hr. b Except for l-ptpe ejeteuie or 2-pipe (jretema not arificed which ehonld be I lb per eq ft BOIL system or equipment. Consideration should be given to rangeability, speed of load changes, and accuracy of regula tion required to properly handle system needs. This is espe cially important with temperature control systems using intermittent flow of steam to heat the building. Certain types of pilot-operated pressure-regulating valves can be used as a temperature control valve in some tem perature control applications, by actuating the pilot by means of a damper operator or small automatic control valve.* Pressure-regulating valve capacities recommended for use with various types of temperature control are shown in Table 11. Care should be exercised in selecting the size of a reduc ing valve. The safest method is to consult the manufacturer. It is essential that sizes of piping to and from the reducing valve be such that they will pass the desired amount of steam.with the maximum velocity desired. A common error is to make the size of the reducing valve the same size as that of the service, or outlet pipe size. Generally, this will make the reducing valve oversized and cause wiredrawing of valve and seat due to the resultant small lift of the valve. On installations where the steam requirements are rela tively large and variable, wiredrawing and cycling control may occur in mild weather or during reduced-demand pe BOILER CONNECTIONS Steam Cast-iron, sectional heating boilers usually have several outlets in the top. Two or more outlets should be used when ever possible to reduce the velocity of the steam in the vertical uptakes from the boiler, and thus to prevent carry ing of water into the steam main. Piping connections to the steam header are shown' in Fig. 32. Return Cast-iron boilers are generally provided with' return tappings on both sides, while steel boilers are generally equipped with only one return tapping. Where two tappings are provided, both should be used to effect proper circulation through the boiler. Recommended piping connections in cluding the Hartford return for a battery of steam boilers having the condensate returned by a pump, are shown in Fig. 32. Connections for a single boiler are shown in Fig. 33. The 90-deg elbow, short horizontal nipple, and tee at the * top of the Hartford connection may be replaced by an in verted Y fitting if the condensate flows to the boiler by gravity. The point at which the condensate enters the equalizer pipe should be 4 in. below the normal water line when a pump is used and usually 2 to 4 in. for gravity return. The inverted Y fitting should not be used if condensate is returned by a pump because the fitting may direct the con densate upward into the equalizer pipe where it will cause noise due to rapid condensation of some steam. Proper se lection of a pump capacity and discharge procure is re- Steam Heating Systems 375 quired in any case because a pump may deliver water' at such a high rate that steam and cold condensate are brought into contact and cause noise. The size of equalizer recommended by the Hartford Steam Boiler Inspection and Insurance Co. is based upon grate area as follows: lYt, 2Vt, and 4 in. for grate areas of 4, 4 to 15, and over 15 sq ft respectively. It should not be less than the size of the main return piping from the system. The equalizer connection should be made as shown in Figs. 32 and 33 so that the steam flows toward it for best balance conditions. If the connection is such that the steam flows across the equalizer inlet, a lowered pressure will result at the inlet and tend to draw the condensate discharged by the pump into the steam thereby causing water hammer. The condensate should enter the common return header of a battery of boilers midway between the end boilers. If the discharge line is more than 25 ft long, a check valve should be installed at the return'header as shown in Fig, 32 in addition to the check valve at the outlet of the pump. If the pump discharge is run at an elevation above the water line a spring-loaded check valve at the return header will keep the discharge line flooded and prevent water hammer which usually follows a system shutdown period. Sizing Boiler Connections Little information is available on the sizing of boiler run outs and steam headers. Although some engineers prefer an enlarged steam header to serve as additional steam storage space, there ordinarily is no sudden demand for steam in a ' ' steam heating system, except during the heating-up period, at which time a large steam beader is a disadvantage rather than an advantage! The boiler header may be* sized by first computing the maximum load that must be carried by any portion of the header under any conceivable method of operation, and then applying the same schedule of pipe sizing to the header as is used on the steam mains for the building. The horizontal runouts from the boiler, or boilers, may be sized by calculating the heaviest load that will be placed on the boiler at any time, and sizing the runouts on the same basis as the building mains. The difference in size between the vertical uptakes from the boiler, which should be of same size as the boiler outlet tapping, and the hori zontal main or runout, is compensated for by the use of reducing ells. Return connections to boilers-in gravity systems are made the same size as the return main itself. Where the return is split and connected to two tappings on the ^mp boiler, both connections are made the full size of the return line. Where two or more boilers are in use,' the return to each may be sized to carry the full amount of return for the maximum load which that boiler wifi be required to carry. Where two boilers are used, one of them being a spare, the full size of the return main would be carried to each boiler, but if three boilers are installed, with one spare, the return lin* to each boiler would require only half of the capacity of the entire system, or, if the boiler capacity were more than one-half the entire system load, the return would be sized on the haaia of the maximum boiler capacity. As the return piping around the boiler is usually small and short, it should not be sized to the minimum With returns pumped from a vacuum or receiver return pump, the size of the line may be calculated from the water rate on the pump discharge when it is.operated, and the line sized for a very small pressure drop. The relative boiler loads should be considered, as in the case of gravity return con nections. Boiler header and piping sizes should be based on the total load. CONDENSATE RETURN PUMPS Condensate return pumps are used for gravity systems when the local conditions do not permit the condensate to return to the boiler under the existing static head. The re turn of the condensate permits the water to pass repeatedly through the cycle of vaporization, with subsequent con densation and return to the boiler. During such repeated cycles any incrustants or other substances in solution are precipitated and the water de-activated to a considerable extent, so that corrosion of a serious nature is seldom ever encountered where the condensate is repeatedly used. Seriouscorrosion is more frequently found in systems in which the condensate is wasted, and fresh make-up water is continually being introduced. A generally accepted condensate pump unit for low-pres sure heating systems consists of a motor-driven centrifugal pump with receiver and automatic float control. Other types in use include rotary, screw, turbine and reciprocating pumps with steam turbine or motor drive, and direct-acting steam reciprocating pumps. - The receiver capacities of these automatic units should be sized so as not to cause too great a fluctuation of the boiler water line if fed directly to the boiler, and at the same time not so small as to cause too frequent operation of the unit. The usual unit provides storage capacity between stops in the receiver of approximately 1.5 times the amount of con densate returned per minute, and the pump generally has a delivery rate of 2 to 3 times the normal flow. This relation of receiver and pump size to heating system condensing capacity takes account of the peak condensation rate. A typical installation of a motor-driven automatic con densate unit-is illustrated in Fig. 10. VACUUM HEATING PUMPS On vacuum systems, where the returns are under a vacuum, and subatmospheric systems, where the supply piping, radiation, and the returns are under a vacuum, it is neeessary to use a vacuum pump to discharge the air and noncondensable gases to the atmosphere and to dispose of the condensate. Direct-acting steam-driven reciprocating vacuum pumps are sometimes - used where high-pressure steam is available, or- where the exhaust steam from the pump can be utilized. In general, however, these have been replaced by the automatic motor-driven return-line heating pump especially developed for this service. Steam-turbine drive is also frequently used where steam at suitable pres sures is available, the steam being used afterward for build ing heating. The usual vacuum pump unit consists of a com pact assembly of exhausting unit for withdrawing the air-vapor mixture and discharging the air to atmosphere, and a water removal unit which discharges the condensate to the boiler. They are furnished complete with receiver, separating tank, and automatic controls mounted as an integrated unit on one base. There are also special steamturbine driven units which are operated by passing the steam to be used in heating the building through the turbine with only a 2 to 3 psi drop across the turbine required for its operation. Under special conditions such as installations where it is necessary to return the condensate to a highpressure boiler, auxiliary water pumps may be supplied. In some instances separate air and water pumps may be used. For rating purposes* vacuum pumps are classified as low 376 CHAPTER 26 1959 Guide vacuum and high vacuum. Low-vacuum pumps are those rated for rpaintAining 5Vi in. Hg vacuum on the system, and high-vacuum pumps are those rated to maintain vacuums above 5Vt in. Hg. The required air and condensate removal capacity of vacuum pumps depends upon the size and type of heating system to which they are applied. The required condensate capacity is closely related to the amount of radiation installed together with the range of the treating requirement. For average design conditions, the theoretical condensing rate of a heating system is approxi mately 05 gpm per 1000 sq ft equivalent direct radiation (EDR) served. Vacuum-pump water-delivery rates gen erally should be the same as for condensate pumps, which range from 2 to 3 times the design condensing rate. This provides sufficient capacity for peak loads t and for inter mittent automatic operation. The wide varying operating range and characteristics of individual heating systems have a greater effect on the quan tity of air to be removed than' on the condensate to be handled. The air-handling requirement cannot be found by applying a common factor to the equivalent direct radia tion design load although this would be possible in de termining the condensate. For low-vacuum systems, where the returns are controlled at an average vacuum of 55-in. Hg vacuum and the temperature averages 160 F, the various manufacturers of vacuum pumps provide pump capacities from 05 to 1.0 cfm of air per 1000 sq ft equivalent direct radiation served. For high-vacuum systems, the vacuumpump air capacity requirements are generally greater. A capacity of 2j0 cfm of air, at 20-in. Hg vacuum per 1000 sq ft equivalent direct radiation served, is a typical capacity furnished on high-vacuum systems. These higher air ca pacities on subatmospheric controlled systems are required basically because of the increase in vacuum which expands the volume of air and vapor that is to be removed to main tain circulation at the higher operating vacuum. It is. particularly important on high-vacuum installations to see that the entire system is tight in order to reduce the amount of inward air leakage and, furthermore, to assure that relatively higher temperature steam is prevented from entering the vacuum return' lines through leaky traps, highpressure drips, etc. The hotter the returns, the lower will be the posible vacuum for a given air leakage into the system. It is for this reason that the condensate from equipment tiring steam at high pressure should not be connected di rectly to a vacuum return line, but should drain to a flash tank or flush leg through a high-pressure trap. The receiver should have an equalizing connection to a low-pressure steam main and drain through a low-pressure trap to the' vacuum return main, as indicated later in this chapter in section on Drips. Vacuum-Pump Controls In the ordinary vacuum system, the vacuum pump is con trolled by a vacuum regulator which cuts in when the vacuum drops to the lowest point desired, and cuts out when it. has - been increased to the highest point, these points being varied to suit the particular system or operating conditions. In addition to this vacuum control, a float control is included which will start the pump whenever sufficient condensate accumulates in the receiver, regardless of the vacuum on the system. A selector switch is usually provided to allow opera tion at night as a condensate pump only, also to give manual or continuous operation when desired. There are several variations in the control of the vacuum maintained on the system by the pump. In some subatmospheric systems where orifices are used, the vacuumpump control maintains a pressure difference between the supply and the return piping, which is held within relatively close limits. There are other subatmospheric systems which utilize special temperature-pressure actuated controls for maintaining the desired conditions in the return lines. Where various zones are connected to the same return main, the return vacuum must be controlled to meet the requirements of the zone operating at the lowest steam supply pressure. Piston-Displacement Vacuum Pumps Piston-displacement return vacuum heating pumps may be either electric or steam driven. Their piston speed in feet per minute should not exceed 20 times the square root of the number of inches in their stroke. They are usually supplied with an air separating tank, open to the atmosphere, placed on the discharge side of the pump, and at an eleva tion sufficiently high to allow gravity flow of the condensate to the boiler. If the boiler pressure is too high for such gravity feed, then an additional steam pump for feeding the boiler is desirable. The extra pump is sometimes avoided by using a closed separating tank with a float-controlled vent. In both arrangements, the air taken from'the system must be discharged against the full discharge pressure of the vacuum pump. In the case of high- or medium-pressure boil ers, it is better to use the atmospheric separator and the second pump. . In figuring the required displacement for such pumps, a value of from 6 to 10 times the volumetric flow of con densate is used for average vacuums and systems. STEAM TRAPS Steam traps, as the name implies, are automatic devices used to trap or hold steam in an apparatus or piping system until it has given up its latent heat, and to allow condensate and air to pass as soon as it accumulates. In general, traps consist of a vessel in which to accumulate the condensate, an orifice through which the condensate is discharged, a valve to close the orifice port, mechanisms to operate the valve, and inlet and outlet openings for the entrance and discharge of the condensate from the trap vessel. Steam traps are classified according to the type of op erating device by which they function. The traps which are available on the market today may be classified as (1) float, (2) thermostatic, (3) float and thermostatic, (4) upright bucket, (5) inverted bucket, (6) flash, (7) impulse, (8) lifting, and (9) boiler return trap or alternating receiver. Float Traps. Float traps operate by the rise and fall of a float due to a change of condensate level in the trap. When the trap is empty, the float is in its lowest position and the discharge valve is closed. As condensate accumulates in the trap chamber, the float rises and gradually opens the valve, and the pressure of the steam pushes the condensate out of the valve. The dis charge from a float trap is generally continuous, since the operung of the valve is proportioned to the flow, of condensate through the trap. A gage glass may be used to indicate the height of condensate in the trap chamber. Unles float traps are well made and proportioned, there is danger of considerable steam leakage through the discharge valve due to unequal expansion of the valve and seat, and the sticking of moving parts. Float traps are made in sizes from 14 to 3 in., and for pressures varying from vacuum conditions to 200 psig. Float traps are used for draining condensate from steam separators, steam headers, blast coils, heating systems, steam-water heaters, laundry equipment, sterilizers, and other equipment. When used for draining low-pressure systems, float Steam Hearing Systems 377 treps should be equipped with a thermostatic air vent (see float and Therimattatic Traps}. Fig. 34 illustrates & single port float trap. Thermostatic Traps. Thermostatic baps function by means of elements which expand and contract under the influence of heat and cold. In early types of thermostatic traps, carbon posts and bimetallic elements were used for expansion. In general, the modem type of thermostatic trap consists of thin corrugated metal bellows or discs enclosing a hollow chamber.The chamber is either filled with a liquid, or a small amount of a volatile liquid, such as alcohol, is introduced. The liquid expands or becomes a gas when steam comes into contact with the expansive element. The pressure created in either case ex pands the element and closes the valve of the trap against the action. Thermostatic traps are made in from Vi to 2 in., Figs. 35 and 36 illustrate types of thermostatic traps which are available at the present time. Float and Thermostatic Traps. This type of trap is a com bination of the float trap and the thermostatic trap, and find* its use in the draining of condensate from unit heaters, blast heaters, and coil heaters for water, oil, or other liquids where there is apt to be a large volume of condensate which would not permit successful operation of thermostatic traps alone. The function of the float element of this trap is to handle the condensate, and of the thermostatic element to permit the flow of air and to prevent the Sow of steam around the float valve. Float and thermostatic traps are made in sizes from Vi to 2 in. and usually operate under pressures varying from vacuum con ditions to 40 psig, although some are made to operate at a maximum pressure of 200 psig. Fig. 37 illustrates a typical float and thermostatic trap. Fig. 35.... Thermostatic Trap ' Bellows Type TtCRMQSTATC Thermostatic Trap Upright Bucket Traps. In this type of trap, the condensate enters the trap chamber and filbi the space between the bucket and the walls of the trap. This causes the bucket to float, and forces the valve against its seat, the valve and its stem usually being fastened to the bucket. When, the condensate in the chamber rises above the edges of the bucket, it overflows into it and causes the bucket to sink, thereby withdrawing .the valve from its seat. This permits the steam pressure acting-on the surface of condensate in the bucket to force the water to | ounxr Fig. 35 .... Thermostic Trap Disc Typeaf escape of steam. When condensate or air comes in contact with the element, it cools and contracts, opening the valve and al lowing them to escape. The discharge from this type of trap is intermittent Thermo static traps find their use generally for the draining of con densate from radiators, convectora, pipe coils, drips, unit heaters, water heaters, cooking kettles, and other equipment. Except for radiators and convectors, it is recommended that a strainer be installed on the inlet connection to the trap to prevent dirt, pipe scale, and other foreign substance from entering the trap. A cooling leg of a length of pipe should'also oe provided ahead of the trap on unit heaters and gimilnr apparatus to cool the condensate in order to help in the trap Fig. 38 .... Upright Bucket Trap the discharge opening. When the bucket is emptied, it rises and closes the valve and another cycle begins. The discharge from this type of trap is intermittent, and it requires a definite differential pressure (usually 1 psi at least) between the inlet and outlet of the trap in order to lift the condensate out of the bucket to the return opening. Upright bucket traps are used for draining condensate and air from blast coils, unit heaters, steam mains, laundry equip ment, sterilizers, water and oil heaters and other equipment. This type of trap is particularly suited for use where there are pulsating pressures, such as occur in draining steam lines anH separators at reciprocating pumps or engines. It is not in fluenced by pulsations or wide fluctuations of pressure. Upright bucket traps are obtainable in sizes varying from Yi to 2vb m., and for pressures varying from vacuum to 1200 psig. Fig. 38 illustrates an upright bucket trap. . 378 CHAPTER 26 1959 Guide Inverted Bucket Traps. Ia this type of trap, steam, con densate, and air enter the trap under tie bell or inverted bucket. Steam floats the inverted bucket and closes the valve. Con densate snipping the trap enables the inverted bucket to fall, opening the valve. 'lire condensate then discharges through the open valve until again enters and displaces the water contained in the bucket, thus restoring its buoyancy. The pressure entering through the open valve discharges the trap. Air is eliminated automatically by passing through the small vent hole located in-the top of the inverted bucket. Inverted bucket traps for use on low-pressure systems, par ticularly with blast coils or unit heaters, are usually furnished with a large capacity opening equipped with a bimetallic thermostatic element which closes when heated by steam, and opens when cooled by air and condensate, allowing air to escape from the inverted bucket to the trap outlet. Inverted The discharge from flash-type traps is intermittent. There are no moving parts in tbia type of trap. The orifice, however, is adjustable for the pressure differential required. A gage glass or float indicates whether the trap is operating. . These traps can be used for draining condensate from steam, water, and oil heaters; blast heaters; unit heaters; dryers; vulcanixers; kitchen equipment; laundry equipment; evapo rators; steam lines; and other equipment, where the pressure differential between steam supply and condensate return does not drop below 5 psi. Flash-type traps are made in sizes from Vi to 3 in., and for pressures varying from vacuum to 450 psig. Fig. 41 illustrates a trap of the flash type. fig. 39 .... Inverted Bucket Trap fig. 41____Flash Trap Impulse Traps. These traps are a modification of the flash trap, and depend on the ame principle of flash for their operation. In the impulse trap the action is utilized to govern the movement of a valve by causing changes in pres sure in a control chamber above the valve. A small portion of condensate, called control flow, bypasses continuously through the control chamber. At low and medium temperatures, the discharge through the center orifice reduces control chamber pressure, and the valve opens for free discharge of air and condensate. ` When condensate reaches near-steam temperature, part of the control flow flashes into vapor, due to reduced pressure in control chamber. The increased volume of the condensatevapor mixture restricts the discharge through the center orifice, and therefore the reduced pressure in control chamber builds fig. 40 .... Inverted Bucket Trap with Central Guide bucket traps are used for draining condensate and air from blast crtitn, unit heaters, steam drips, laundry equipment, steri lisers, steam water heaters, and other equipment. They are particularly suited for draining condensate from steam lines or equipment where abnormal amounts of air must be dis charged, where there is also foreign matter such as dirt, sludge, and oil draining to the trap. The discharge from inverted bucket traps, like that of the upright bucket traps, is intermittent and requires a definite differential pressure between the inlet and the outlet of the trap in order to lift the condensate from the bottom of the trap to the outlet of same. Inverted bucket traps are made in sixes from Vi to 3 in., and for pressures varying, from vacuum to 2400 psig. Figs. 39 and 40 illustrate some of the types of inverted bucket traps which are available on the market at the present time. Flash Traps. These traps depend on the property of con densate at a high pressure and temperature to flash into steam at a lower pressure. Condensate flows freely through the orifice of-the trap due to the pressure difference from inlet to outlet of trap until steam enters the inlet chamber and mixes with the remaining condensate, heating the condensate and causing it to flash, thereby choking the flow through the orifice and allowing more condensate to accumulate in the trap. fig. 42 .... Impulse Trap up, closes the valve, and shuts off all discharge of hot con densate, except the amount flowing through center . orifice. . Under normal condensate loads, the valve opens and closes at short intervals. Under heavy loads, the valve opens wide and the discharge is heavy ana continuous. Impulse traps can be used for draining condensate from steam mains, unit heaters, laundry equipment, kitchen equipment, oil and water heaters, sterilizers, and other equipment where the pressure at the trap outlet is not greater than 25 percent of the inlet pressure. Im pulse traps are made in sizes from Vt to 2 in., and for pres sures ranging from 1 to 600 psig. Fig. 42 illustrates a trap of the impulse type. Lifting Traps. This type of trap is an adaptation of the up Steam Heating Systems right bucket trap. It has the added feature of an auxiliary pressure inlet through which steam is introduced at a pressure higher than that of the trap inlet pressure. This high-pressure steam forces the condensate to a point above the trap, and against a back pressure higher than that which is possible with normal steam pressure. Lifting traps are made in . sizes from 1 to 3 in, and for pressures ranging from vacuum to 150 psig. Fig. 43 illustrates a trap of the lifting type. Boiler Return Trap or Alternating Receiver. This device is not actually a steam trap in that it is not used to trap or bold steam, but is an adaptation of the lifting trap. It is used for returning condenrate to a low-pressure boiler, when due to excera pressure, the condensate cannot flow to the boiler by gravity without flooding the return mains, end endangering the boiler by permitting it to go dry. The boiler return trap is a vessel (vented to the atmosphere) in which condensate col lects until a float-operated mechanism equalizes the boiler nH 379 paired and condensate drained through the throttled bypass valve. 3. Whenever it is necessary to install traps for lift service,. as when the condensate must be discharged to a main located above the trap, or where the trap must discharge against a definite back pressure, a check valve and a gate valve should be installed on the discharge side of the trap, the check valve to prevent continuous presure on the discharge aide of the valve, and the gate valve to shut off pressure in case the trap is removed for service or repair. DRIPS A steam main in any type of steam heating system may be dropped to a lower level without dripping if the pitch is downward with the direction of steam flow. The steam main in any heating system can be elevated if dripped. Fig. 45 shows a connection where the steam main is raised and is drained to a wet-return. If the elevation of the low point fig. 45.... Dripping Main Where It Rises to Higher Level is above a dry-return, it may be drained through a trap to the dry-return in two-pipe vapor, vacuum and subatmospheric systems. Horizontal steam pipes may lwn he run over obstructions without a change in level, if a small pipe is carried below the obstruction to care for the condensate (Fig. 46). Horizontal return pipes may be carried past door ways and other obstructions by using the schema illustrated in Fig. 47. It will be noted that the large pipe, in this case, runs below the obstruction, and the smaller one over it. These traps are available in sizes from 114 to 214 in, and for pressures varying from 0 to 100 psig. A typical boiler return trap is shown in Fig. 44, and a typical connection to a lowpressure heating system m Fig. 14. Steam Trap installations The following general rules should govern the installatirm of traps of all types: 1. A vertical drip, as long as possible, and a strainer should be installed between the trap and the apparatus it drains. Exceptions to this rule are the installation of thermostatic traps in radiators, convectors, and pipe coils. These, in general, are attached directly to the units without strainers. . 2. Whenever it is necessary to in continuous aerv- ice, apparatus which is to be drained, it is advisable to install a gate valve on each side of the trap, and a valved bypass around the trap, so that the trap may be removed and re fig. 46 .... Looping Main Around Beam fig. 47.... Looping Dry Return Main Around Opening Offsets in steam and return piping should preferably be made with 90-deg ells, but occasionally fittings of other angles are used, and in such cases the length of the Hiagnnal offset will be found as shown in Fig. 48. Dirt pockets, desirable on all systems employing thermo static trape, should be so located as to protect the traps from scale and sludge which will interfere with their operation. Dirt pockets are usually made 8 in. to 12 in. deep, and serve as receivers for foreign matter which otherwise would be carried into the trap. On vapor systems where the end of the steam main is 380 CHAPTER 26 1959 Guide dripped into the wet-return, the air venting at the end of the is aranmplishftrf by an air vent passing through a thermostatic trap into the dry-return line as shown in Fig. 49. On low-pressure or vacuum systems, the ends of the steam to take place. The iuw-presoure steam therein gen erated is passed directly to the low-pressure, steam mains, and the condensate is discharged through a second trap to the low-pressure or vacuum return. A typical arrangement of a flash leg, with sizes required for varying capacities, is given in fig. 52. CONNECTIONS TO HEATING UNITS Riser, radiator, and convector connections must not only be properly pitched at the time they are installed, but must Rg. 48____Constants for Determining Length of Offset Pipe steam maina are dripped and vented into the return through drip traps opening into the return line. A float and thermo static type trap is recommended for dripping steam mains and risers as indicated in Figs. 50 and 51. The dripping of high-pressure mains, or of equipment using high-pressure steam into low-pressure or vacuum re- Rg. 50.... Dripping End of Steam Main-into ' Dry Return Rg. 49.... Dripping End of Main into Wet . Return turns, is generally accomplished by the use of a flash tank or flash leg into which the high-pressure trap is arranged to discharge. This tank provides the required space for the flashing from high-temperature condensate to low-pressure MAM ` POCKET Rg. 51.... Dripping Heel of Riser into Dry Return - be arranged so that the pitch will be maintained under the strains of expansion and contraction. These connections may be made by swing joints which permit the expansion or con traction to occur under heating and cooling without bending of pipes. To take care of expansion in long risers, either expansion joints of commercial construction or pipe swing joints are used. Anchoring of pipes between expansion joints is desirable. ^ _ Two satisfactory methods'of making runouts for one-pipe systems for either the up-feed or the down-feed type are Table 12.... Dimensions Applying to Rg. 52 Steam Hearing Systems PLAN 381 fig. 57.... Typical Connections ta>finned2 Pipe Convector Heating Coils Arranged for Series How of Air fig. 54.... Two-Pipe Top and Bottom Opposite End Radiator Connections Hung on Wall fig. 59.... Typical Connections to Finned-Tube Blast Heating Coils Arranged for Parallel Flow of Air Rg. 52____Rash leg installation for 80 Psi Maximum Steam Working Pressure fig. 60....Typical Connections to Finned-Tube Blast Heating Coils of the Steam Distributing or Nonfreeze Type 382 CHAPTER 26 SM7 MW 1959 Guide Rg. 61.... Typical Return Connections to Finned-Tube Blast Heaters with High-Pressure Steam shown in fig. S3. Where the vertical distance is limited and the runouts must run above the floor, the radiator may be set on pedestals or raised by means of high legs. A method of connecting a unit heater to a one-pipe steam heating system is illustrated in Fig. 2. Typical two-pipe radiator connections are shown in figs. 54 and 55. While these show top inlet supply connections which are preferred, it is also possible to connect the supply to the bottom of the radiator. Short radiators may be con nected with top supply and bottom return on the same end. A typical method of connecting convectors is shown in fig. 56. Sometimes the supply valve is omitted on con vector connections, and a damper is supplied in the outlet grille for heat control. A typical connection for. finned pipe convectors is shown in fig. 57. Typical connections to blast heaters are shown in Figs. 58, 59, and 60. fig. 61 shows a typical return and connec tion for blast heaters connected to high-pressure systems. A typical two-pipe connection to a unit heater is indi cated in fig. 62. for Two-Pipe System CONTROL VALVES Gate valves are recommended in all cases where service demands that the valve be either entirely open or entirely closed, but they should never be used for throttling. Angle globe valves and straight globe valves should be used for throttling in such cases as bypasses around pressure-reducing valves or on bypasses around traps. REFERENCES XF. C- Houghten and J. L. Blackshaw: ASHVE Research Repost No. 954--Condensate and air return in steam heating systems (ASHVE Transactions, Vol. 39, 1933, p. 199). * Reducing and relief valves on consumers'premises (Ameri can Standard Code for Pressure Piping, ASA B31.1-1955, p. 66). * American Standard Code for Pressure Piping (ASA B31J1955, p. 66). *N. H. Davidson: Economies effected by combination pres sure and temperature control valve (National District Heat ing Association Proceedings, 1956). *ASHVB Standard Code for Testing and Rating Return Line Low Vacuum Heating Pumps (ASHVE Transactions. Vol. 40, 1934, p. 33). CHAPTER 27 DISTRICT HEATING Steam Requirements, Bailer Plants, Steam Distribution, Desgn Considerations, Distribution Pressures, Pipe Sizes, Conduits: * for Piping, Manholes and Tunnels, Accessory Equipment, Insulation, Return of Condensate, Building Piping and Equipment, Metering, Hot Water Distribution THE term district heating refers to the supplying of heat from a central plant to a group of buildings in a city, system) to the maximum hourly send-out, which is a direct, measure of the extent to which investment in facilities is used. It is often employed to determine savings by equipment institution, housing development, or industrial or commeroffering higher efficiency. The load factor for space heating is cial area. The heat may be used for any applicable purpose usually between 15 and 30 percent. For space heating plus such as space heating, air conditioning, or processing. It is usually preferable that groups of commercial, industrial, or additional steam requirements such as water heating, cooking, or laundry, it is between 15 *nd 40 percent. Where process requirements predominate, as in factories, load factors are institutional buildings be supplied with heat from a central -sometimes 50 percent or more. Load factors for various types plant rather than from individual plants in order to permit of buildings are given in Table 9, Chapter 37. - design for better combustion efficiency with less expensive fuel, and reduction of labor per unit of output. The central plant justifies use of more competent personnel, and often decreases the investment required. Those phases of district heating which frequently fall within the province of the heating engineer are treated here, and information is given for solving incidental prob lems. Some data are included with reference to special re 2. Duration of plant output. The imillative number of hours for the various plant aend-outs and the predicted peak boiler Hpmand on the coldest day are used in conjunction to determine the number and sizes of boilers, in order to effect most efficient loading of individual units and the plant as a whole. The cumulative number of hours a typical district heating plant will send out steam at various plant outputs, with outputs expressed in percentage of maximum hourly rate, is given in Table 3. It will be noted that the duration of plant output for the higher send-outs is very low. quirements for steam piping in buildings served with district steam. The data are confined principally to the use of steam as the heating medium, but the use of hot water has gained some recognition in recent years.1 3. Peed-water treatment. Good feed-water treatment is an absolute necessity in a plant in order to be able to operate the boilers at maximum outputs. Dirty tubes will limit boiler capacity. Proper feed-water treatment will prevent corrosion and scale formation and keep boiler outage to a minimum. In the design of a district heating system to provide public 4. Smoke abatement. This is a modern requirement. The utility service in a city, it is advantageous to make a thorough study of the entire problem with competent men having experience in both design and operation of such systems. installation of suitable fuel-burning and dust-collecting equip ment to limit the emission of smoke and fly ash is usually necessary. 5. Plant location. A boiler plant location is determined by an economic study of fuel handling, water supply, system STEAM REQUIREMENTS The first step in the design of a district heating systefn is to determine the mAiimum hourly and the annual steam piping, land costs, and other associated factors. Such a study usually reveals that the economical location of the plant will be' near the distribution center, in order to simplify and shorten the distribution piping. Plant location and the local air pollu tion ordinances will have a direct bearing on the type of firing requirements of each of the buildings to be supplied. Methods equipment selected and the dust collection apparatus required. of determining the maximum hourly requirements will be found for space heating in Chapter 12, for building service- STEAM DISTRIBUTION water beating in Chapter 56, and for various process ap plications in Table 1.* Measured demands of several types of buildings are given in Table 9, Chapter 37. Methods of estimating annual steam requirements for heating various types of buildings are also given in Chapter 37. Table 7 in Chapter 37 lists the average annual steam consumption per degree-day for buildings located in all sections of the United States. Annual steam requirements for building service-water heating are given in Table 2 of Distribution piping in district heating systems must be designed in accordance with the same basic principles ap plying to any other steam piping. The piping may be run through buildingB, through the air on poles or other struc tures, or underground in conduits or tunnels. Local condi tions and investment will be governing factors in establishing the route of the pipes. Design Considerations . this chapter. Additional data on annual steam requirements, including those for process uses and air conditioning, of vari ous types of buildings in a number of cities may be found in the District Heating Handbook, Third Edition.* BOILER PLANTS In the design of a plant for district heating, consideration should be given to the following factors: 1. Annual load factor. This factor is the ratio of the average hourly plant eend-out (defined as rate of flow to the distribution Important points in laying out distribution piping are: 1. Piping within buildings or basements is normally least, expensive to install and to maintain. . 2. Underground installations involve excavation which rep resents a substantial portion of the total cost. The depth of such excavations should be kept to a minimum after due con sideration has been given to the possible damaging effect of the operating-fine heat on lawns and shrubbery and the pos sible damage to the underground structure due to heavy traf fic, etc. 3. Walking tunnels usually are not provided for steam mains 383 384 CHAPTER 27 1959 Guide Table 1 .... Unit Steam Consumption of Process Equipment* Kitchen AppDancos (xdvo'v* of water heating) Consump tion,* Lb par Hr Pressure, prig Hospital Equipment Consump tion,* Lb par Nr Pa Stock and vegetable kettles (per 5 gal) Vegetable steamers (per compartment) Steam tables (per sq ft) Bain-Maries (per sq ft) Coffee urns (per gal) 20.0 40.0 1.7 3.4 3.4 7-20 7-20 7-20 7-20 7-20 Water urns (per gal) - Soup warmers (30 x 30 x 28 in.) Ffir boilers (3 compartments) Clam, lobster, and potato steamers (per com- partment) Oyster pots 5.0 100.0 18.0 40.0 18.0 7-20 7-20 7-20 7-20 . 7-20 Plate and cup warmers (per 20 cu ft) Food-warming ovens (per 20 cu ft) Silver burnisher and washers Dishwashers (per tray) 35.0 35.0 69.0 60.0 7-20 7-20 7-20 7-20 Sterilizers, for bottles or pasteurisation (per bottle) Sterilisers, for water, (per gal) Sterilizers, for instruments and utensils 8 x 9 x 18 in.,water depth ZH in. 9 x 10 x 20 in., water depth ZH in. 10 x 12 x 22 in., water depth 4 m. 12 x 16 x 24 in., water depth 4 in. 10 x 12 x 36 in., water depth 4 in. 16 x 15 x 20 in., water depth 10 in. 20 x 20 x 24 in., water depth 24 in. Sterilizers, for instruments @ 240-250 F 12 x 20 in. 14 x 22 in. 16 x 24 in. iavadry Equipment Tumblers 40 x 94 in. 30 x 36 in. Washers, (per gal water heated) Flatwork ironere, 100 to 120 in. chest type (per roll) 50 to 100 in. cylinder type (per machine) Standard presses Large shirt bodv presses Cuff and neckband presses Sleevers - Steam-electric irons Woolen pressing machines Large--electric vacuum Small--electric vacuum Small--steam vacuum Feather cleaning and sterilizing 15 pillows per hr ' 360 225 1 60 60-120 105 190 15 12 8 25 12 35 . 20 175 100 100 15-100 100 100 100 100 100 100 100 65 65 65 65 100 Sterilizers, for surgical supplies 10 x 20 in. 12 x 20 in. 14 x 22 in. 16 x 24 in. 16 x 36 in. 20 x 28 in. 20 x 36 in. 20 x 48 in. 20 x 60 in. Sterilizers, (autoclave) (240-250 F) 15.5 x 24 in. 17.5 x 26 in. 21.5 x 30 in. 24 x 36 in. Disinfector, mattress 30 x 42 x 84 in. 60 x 66 x 108 in. Blanket warmers 18 x 24 x 72 in. - * From District Seating Handbook (National District Seating Asocfetioa, Third Edition, t$SI>. b Theee values represent approximate requirements after warm-up period. 1 12 27 30 39 60 66 92 144 48 60 72 10 22 28 38 54 60 78 98 124 24 32 40 42 42 318 4 40 40 40 40 40 40 40 40 40 40 40 40- 40 40 40 40 40 40 40 40 40 40 40 40 40 35-60 35-60 35-60 in the district heating industry because of their relatively high first cost as compared with smaller conduits unless they are re quired to accommodate miscellaneous other services or to pro vide underground passage between buildings. 4. Overhead piping on poles or structures is generally less expensive than underground lines, especially in some institu tional and industrial areas and may be a means of eliminating buried conduit in areas where underground installations would be expensive or undesirable. Thin corrugated aluminum sheets or asphalt-saturated asbestos felt are available for covering the insulation on lines exposed to the weather. Such lines may introduce freexe-up problems, higher heat losses and, in many locations, would be considered unsightly. 5. High-pressure transmision feeders may be employed where the plant is remote from the distribution area, or where it is desirable to augment the capacity of an existing system Design of such feeders and of distribution systems for various load conditions is covered fully in District Heating Handbook, 3rd Edition* 6. Piping routed in loops with suitable valves to provide alternate feeds for major loads, allows service to be maintained despite trouble in any one feeder.* 7. It is desirable to estimate as for as possible the probable growth and change in load centers. Since character of the dis trict served is almost certain to change with time the distribu tion system must be planned so that it can be adapted to accommodate changes. It is helpful to provide a master dis tribution plan which can be revised from time to time to suit conditions as the system grows. Steam Distribution Pressure . The pressure at which the steam is to be distributed will depend upon that available at the plant and pressure re- quirements of apparatus to be served.* ' The advantages of low-pressure distribution (2 to 50. psig) compared with high pressure are: (1) lower heat loss per square foot of pipe surface; (2) lower losses from leakage, trap discharge, and venting; (3) less trouble with traps and valves; (4) less trouble from flash steam at drain age points; (5) simplified problems in pressure reduction at the buildings; (6) suitability of standard fittings; and (7) general reduction in maintenance costs. Some beating companies find that the overall losses in' relation to steam delivery are higher with high-pressure dis tribution. With distribution pressures not exceeding 50 psig, there is less danger if the full distribution pressure should build up in the radiators or heaters through the faulty operation of pressure-regulating valves. With pressures District Heating Table 2 .... Annual Steam Consumption for Water Heating for Various Types of buildings, per Cu Ft of Volume*-b Type of budding Consumption, Lb/IFr) (Cu ft) Consumption Lb/(Vr) (Cu ft) (100 F deg Temp, bite of Wafer) Residence club Apartment bouse Department store Office Theater Parking garage 3.20 2.56 2.41 0.95 0.85 0.57 . 0.46 2.66 2.11 1.99 0.79 0.71 0.48 0.38 * Based on analysis by foorteea district heating companic* from metered con sumptions. Boildinx volume is approximate grow volume. b Fran Disniet Beating Handbook {National District Heating Amodation, Third Edition, 1951, p. W7). 385 Table 3 .... Load Duration for Typical District-Heating System (Cumulative Hour* of Plant Send-aut per Vow at Various Loads Expressed m Percent of Peak Hourly Load*) Plant Output % of Peak Hours per Year Plant Output % of Peak Hours per Year 100 5 55 1800 95 40 50 2200 90 90 40 1 3100 85 150 30 4100 80 300 20 5150 75 500 15 5700 70 750 10 6400 65 1050 6 8760 60 1400 * nnnr1 an enrv on pace 89, District Heating Handbook, Third Edition, 1951. Not*: A plant having * peek send-out of 100,000 lb per hr will aend oat 80,000 (80 percent of 100,000) lb per hr or mere lea 800 hr per jrr. higher than 50 psig, or the safe working pressure of heating - of the several buildings served. In this connection, allowance or process equipment, a second pressure-reducing valve or .should be made for the diversity of the load, that is, the some form of emergency relief is required to prevent exces ratio of the coincident maximum demand of all of the group sive pressures in the radiators or other equipment* of buildings served by the main, to the sum of the individual Pressure reducing valves .are more fully described in maximum HemanHa of each of the buildings served. This Chapter 26 (Steam. Heating Systems). The installation of ratio is known as the Coincidence Factor and varies from reducing valves on district steam installations, however, may 0.50 in some institutional groups to 0.90 in areas where loads present specific problems that are not normally encountered are principally for haating and heat is turned on at about in building steam heating applications. Utility companies in the same time each morning. Consideration should also be some in&tanepq must assume greater responsibilities in their given to the net total load on a line, based on a study of operation and maintenance and are often under regulations the loads in the various buildings, in order to determine the that are different for various cities. " relative merits of providing one or more separate supply The advantages of high-pressure distribution are: (1) lines to serve all-year loads. Such lines will permit turning off smaller pipe sizes; (2) availability of the steam for various the mains that supply strictly seasonal space-heating loads other operations requiring higher pressures than the build during the summer months. ing heating system; and (3) wider flexibility in allowance When lengths of pipe, steam quantities, and initial and for mnrimum pressure drop. Where distribution pressures terminal pressures have been chosen, the pipe sizes can be are not as high as desired, higher pressures can be obtained calculated by means of Figs. 22 to 26 of Chapter 26. The by use of a steam compresor* district-heating industry, however, uses Unwin's formula for It is sometimes desirable to install a separate high-pressure determining pipe sizes because pressure drops can be de line from the boiler plant for steam supply to laundries or termined simply and directly from a chart. This formula other high-pressure equipment rather than to operate the has been checked by tests, and found correct within ranges . entire distribution system at higher pressures. - of velocity used in district heating. A convenient chart de Pipe Sizes veloped from this formula is available from the National District Heating Association/ In district heating work it is common practice to design the piping system on the basis of pressure drop. The initial pressure and the minimum permissible terminal pressure are specified, and the pipe sizes are so chosen that the required amount of steam, with suitable allowances for future in creases, will be transmitted without exceeding this pressure drop. The steam velocity is therefore almost disregarded and may be very high. Velocities of 35,000 fpm are not considered high for pipes in conduits. Where pipes pass through build ings, however, consideration should be given to the pos sibility of objectionable noise due to high velocity. By the use of permissible pressure drops with high velocities, after allowance has been made for future increase in load, the pipe sizes may be kept to a minimum with consequent savings in investment. Some lines in a loop system may need to be in creased in size in order to handle reverse-direction flow in emergencies.4 The steam flowing through any section of the piping can be computed from a study of the hourly steam requirements Conduits for Piping Conduits for underground steam pipes are used to pro tect the pipe and insulation from external damage and to provide a space in which the pipe is free to expand or con tract while held in proper alignment. The conduit should be constructed of non-corrosive materials, or, if of metallic content, should be suitably protected against corrosion. It must be of adequate strength to withstand the earth and traffic forces to which it will be subjected. The conduit should be reasonably waterproof and in many cases provision should be made to drain seepage from its inside. With any form of conduit unless it is actually below water level, provision should be made to completely exclude water or to carry away ground water and prevent it from collecting around the conduit. This is often accomplished by placing a layer of coarse gravel or stone underneath and partly surrounding the conduit with one or two lines of tile having open joints which serve to carry the water to a sewer or other suitable ' . 386 CHAPTER 27 1959 Guide outlet. Proper foundations should be provided to prevent settlement and to insure proper pitch of piping at all times. Manhnlftfl may be required at intervals to provide access to valves, traps, and expansion joints. They should be drained. Some safe means of disposing of condensate from piping should be provided. There axe many types of conduits. They faU into six fol lowing general classifications: Box-type, Solid-pour, Pre fabricated, Tile, Monolithic, Granular Fused, and Water proof. Cross-sections of a few of the typical types are shown in Fig. 1. Box-type conduits are typical of those built with common materials and have many variations. Conduit A, Fig. 1, shows a commonly used type in which a corrugated metal form is placed as an inverted U over the insulated pipe line in stalled on a concrete slab. The concrete may be reinforced or not, depending upon the load on the conduit. Drainage is provided by the drainage pockets filled with crushed stone or gravel and may be installed on either or both sides of the conduit. They conduct water from the top of the conduit to the drain below which is connected to the sewer or some other disposal facility. Variations of the concrete-box type have side walls constructed of hollow vitrified tile, concrete blocks, or other suitable materials, and covered with a re inforced concrete slab. The top and sides are sometimes covered with a waterproofing membrane of asphalt or hot pitch and roofing paper. The solid-pour construction, Conduit B, fig. .1, is also usually made with common materials and consists of poured structural concrete which is vibrated and tamped around a conventionally insulated steam line. If the insulation has a high compressive strength it can support the pipe, other wise, the pipe should be supported independently. Reinforc ing is sometimes used to prevent settlement. An eccentric space may be left around the pipe by using insulation larger than the outside diameter of the pipe to permit upward movement of the pipe during the warm-up periods. During construction, pipe is suspended by wires. Precautions should be taken to prevent the pipe from floating. The top of the conduit should be coated with asphalt emulsion or tar to help 'seal shrinkage cracks. Anchor stresses are higher with this type of construction. Variations of this type include en closure of the pipe and insulation in tile, concrete, steel, or asbestos pipe and then pouring of concrete around outer pipe. This method provides space for pipe supports, if needed. External drainage can be provided by -methods similar to the concrete box type construction. Conduits constructed of common materials are often pre ferred by the district beating industry because of the condi tions imposed in congested street .beds, heavy traffic leads, and drainage conditions or because of the ease of opening and closing the conduit, for branch pipe connections. Prefabricated conduits, C and D, Fig. 1, are commonly constructed in standard lengths. In some, as in C, the in sulated pipe or pipes are placed within a corrosion-resistant helically-corrugated metal jacket which is protected with a heavy asphaltic coating. Similar casings are made of steel protected with an. anti-corrosive compound. Both are of welded construction and can be tested under air pressure. In conduit D.the insulated pipe is placed concentrically within the corrosion-resistant metal jacket and the inter vening space between jacket and insulation poured full of high melting-point asphalt or left as an air space. In these conduits, the pipes are supported by precast rings or guides .. . __ CORRU GATED ZINC COATED MOOT IRON COfCUT ISOLATION TAL JACKET -BROKEN STONE CROSS SECTION District Heating 387 to maintain alignment and to prevent pressure on insulation. Fittings are available for joints, bends, etc. Some of these conduits arc also available with cast-iron casings. Tile conduit E, Fig. 1, is constructed of specially-shaped glazed vitrified bell-and-spigot tile. In the conduit shown, the base drain is made in separate units and is designed to support the main conduit and pipe lines, and to drain the conduit. All joints are cemented. There are several types of tile conduits. - Monolithic conduits F and G, Fig. 1, are similar to the solid-pour type except that the insulation, referred to as in sulating concrete, serves also as a conduit and is poured di rectly around the steam main. The insulation consists of expanded-mica, shredded-rubber or other cellular materials mixed with Portland cement or asphalt; or of a special foaming material mixed with Portland cement. The latter process creates a multitude of minute air cells in the con crete to obtain its insulating qualities. The poured structure is often protected by a water-proofing membrane and strengthened by a concrete duct. Granular-fused type conduits such as H, Fig. 1, consist of a specially sized and selected granular bitumen which is poured in the trench around the pipes. The manufacturers advise that the conduit is formed when heat passing through the pipes forms three distinct concentric zones, all resistant to water penetration. A plastic area surrounds the pipe, outside of which is a sintered zone providing thermal insula tion, and finally, an outer layer of unconsolidated particles providing further insulation value. This unconsolidated zone is also the load-bearing portion of the structure. Waterproof conduits are intended for use where perma nency and thoroughly tight joints are required. Some of the prefabricated conduits, C and D, Fig. 1, can be supplied with water-tight cast-iron carings and fittings. The rawing shown in I, Fig. 1, consists of cast-iron pipe with lead-caulked joints enclosing the insulated steam mam It is water tight and intended for special applications, where, for instance the duct may be submerged, subject to flooding, or laid in ex tremely wet soil. All of the preceding conduits have their application and the choice depends upon local conditions. Any underground conduit is only as good as, among other things its founda tions to prevent settlement, its external and internal drain age, its ability to stand up under the corrosive action of cer tain ground conditions (see Buried Pipe Lines, Chapter 55), its strength to carry the load imposed on it, its field in stallation, and its insulating properties. Manholes . When conduits are used for underground piping, manhnlwa may be required to house valves and other accessory equip ment. They are built of a variety of materials such as rein forced concrete block. They should have adequate volume to permit men to work on equipment. They should be as nearly waterproof as possible and precaution should be taken to prevent entrance of surface water around the covers. Pro vision should be made for lifting necessary equipment from the pipe line, for drainage, for ventilation, and for auto matic water-removal equipment if a sewer is not accessible. Details of typical manhole construction housing a ringla expansion joint are shown in the NDHA District Beating Handbook, Third Edition, p. 164. If more equipment is in stalled, the size should be increased accordingly. Where water removal equipment is required, sumps are installed under the manholes. Water ram be removed periodi cally with portable pumps, or, where water conditions axe bad or periodic inspection is not feasible, by installed sump pumps or water ejectors. The motors for electric pumps should be enclosed in a separate compartment which is ventilated to protect it from beat and vapors. Precautions should be taken against corro sion as mentioned in the Section Piping and Accessory Equipment. Piping Tunnels Because of their relatively high first cost as compared with conduits, walking tunnels are usually not provided for steam mains unless, as in some institutions, they are required to accommodate miscellaneous other utility services or to pro vide underground passage between buildings. Tunnels are usually built of reinforced concrete, brick, con crete blocks or other suitable structural materials, and are waterproofed on the outside. Provision for drainage and ventilation is essential. Since tunnels and conduits are apt to be hot and humid, special precautions should be taken to reduce temperatures and protect equipment. Heat loss from pipes and supports 'can be reduced by inKiil*tmg return maing and ring more than normal insulation on steam mains. A metal jacket over the pipe covering can permit insulation to carry the weight of the pipe* The precautions on sizing, design, installation, and pro tection against corrosion, for accessory equipment, as dis cussed in the sections Piping and Accessory Equipment, and Conduits for Piping, should be taken for tunnels. Special precautions should be taken to prevent rapid deterioration of enclosed electrical conduit. All electrical boxes, junctions and outlets should be vapor proof. Ventilation of the tunnel can be obtained by installation of suitable fans or by natu ral means Piping and Accessory Equipment A district heating distribution system is usually buried in the ground where it is not readily accessible for repairs or replacement. This makes it imperative that the system be carefully designed and installed. Hie American Standard Code for Pressure Piping ASA B-31.1--1955* has sections, covering district heating piping systems and fabrication de tails, from which general specifications and minimum re quirements for piping and accessory equipment can be ob tained. ' Suggestions for selection and installation of materials based on long operating experience of the district heating industry are given in following paragraphs. More detailed informa tion is available in the District Heating Handbook, Third Edition" Pipe. Either steel or wrought-iron pipe is satisfactory. Welded construction is most desirable. Valves, flanged cast-iron valves for pressures under 125 psig are satisfactory. For pressures from 125 to 300 prig flanged-steel and welded-end valves are used. Outride screw and yoke valves are preferred. Fittings. Forged or rolled steel is used for pressures in excess of 125 prig. Where pipe-line apparatus is to be re movable, flanged fittings are preferred. Expansion Joints. Pipe bends to absorb expansion are preferable wherever feasible in order to eliminate the in spections, maintenance, and housing required by slip joints. Slip joints should be guided either externally or internally, or both. Corrugated-type joints should have stainless steel i 388 CHAPTER 27 1959 Guide or copper corrugations depending upon operating conditions. Spare expansion capacity should be allowed for contingencies such as higher pressures, superheat, and installation toler ances. .Anchors. Anchors can be of structural steel, special fittings, or U-shaped steel straps which partially encircle the pipes. Anchors should be firmly bolted or welded to a short length of cast or stainless steel set in concrete. Anchors are often fabricated by welding structural steel to pipe and embed ding the ends in manhole walls or concrete poured in connec- ' tion with conduit. Anchors are subject to humid conditions in conduits and manholes, and can deteriorate rapidly. They should be designed for adequate strength, intended life, and the steam pressure to which they can be subjected, with liberal factors of safety and protection from corrosion. An chors should be attached to both sides of the pipe. Lugs should be welded to pipe on both sides of loop-type anchors to prevent slippage. The cantilever type of anchor'should be avoided. Cast steel is preferred to cast iron for anchor material. . Alignment Guides. To assure pipe alignment and proper operation of expansion joints, pipes should be adequately guided. Special precautions should be taken if the pipe de viates from a straight line. Pressure Reducing Valves. Suitable single-seated valves are preferable. The valves should be selected from the manu facturer's rating regardless of pipe size. Pressure gages are necessary at valve and control points. Valves require some auxiliary source of power for valve positioning, if they are to be controlled from a remote point to regulate terminal pressure. (See Chapter 26 for detailed recommendations re garding pressure reducing valves.) . Traps. To assure adequate drainage of piping, extra trap capacity and large drip pockets should be provided. Extra heavy or corrosion-resistant trap discharge piping is de sirable. On steep grades or in high-velocity steam mains, special deflector scoops or baffles should be placed in the line to direct condensate into traps.*1 Supports. Due to humid conditions in conduit and man holes, it is desirable to use stainless steel supports. Instruments. The instruments required will be the same as for other steam systems as described in Chapter 43, Auto matic Controls, or Chapter 44, Instruments and Measure ments, with modifications depending on the records desired with regard to pressures and temperatures maintained or the records of response of the system to varying load demand.1* Branch Connections. Branch connections should be made at or near anchor points; if not, ample clearance must be provided around the branch to take care of pipe movement. Insulation Insulating materials constitute a primary element of dis trict steam distribution structures and must be suitable for underground service. Insulation should be noncombustibie, vermin-proof, moisture-resistant, durable, non-corrosive to steel pipe especially when wet, and able to retain its posi tion in relation to the pipe line. It should be of a type which, if flooded, will dry out and regain its original physical, chem ical and insulating properties. It should be relatively un affected by such chemicals as are usually found in ground or other contaminated waters. It should have the lowest practical heat conductivity consistent with the given re quirements. Insulating properties vary with soil conditions, weather variations, types of conduits used, and, if in tunnels, the amount of ventilation. The selection of insulation to provide ior the various conditions is covered in District Routing Handbook--Third Edition. Where underground insulation is applied directly to the pipe, copper wire is normally used to band the covering. Insulation may be poured as a mono lithic structure in a suitable duct. Where insulation in an existing conduit has deteriorated the line may be reinsulated with a minimum amount, of excavating by use of some of the materials used in monolithic conduits." Insulation is dis cussed further in Chapter 32, and studies of heat loss from bare and insulated buried pipe are given in District Heating Handbook" and in Piping Handbook." RETURN OF CONDENSATE If the condensate can be returned to the plant to be used for boiler feed water at an overall cost less than that re quired to process raw water, the installation of return lines parallel to the steam supply lines should be given considera tion. A typical analysis of comparative costs of returning condensate and processing feed water is given in District Heating Handbook Return of condensate by gravity is desirable, but usu ally because of terrain conditions or user's return facilities, the condensate is pumped back under pressure. Pipes carrying condensate are more subject to corrosion than other parts of the system. Care must be taken to give proper pitch to the pipes and to provide proper venting of non-condensable gases. (See Chapter 55, Corrosion.) BUILDING PIPING AND EQUIPMENT There are certain fundamental principles that should be followed in the design of a building heating system which is to be supplied from district steam mains. Some of these are unique to district heating and some, although they may apply to any building have been demonstrated to be par ticularly important when district steam is used. District hpAting companies have certain regulations regarding the consumer's installation to safeguard the mutual interest of supplier and consumer and to insure satisfactory and eco nomical service. When an installation is designed, local regu lations and code requirements" should be observed. Zoning. Where the hours of occupancy or heating loads differ in various sections of the building, it is good practice to infitAll separate supply lines to the different sections. For example, in an office building with first floor stores or res taurants open in the evening, a separate main supplying the first floor will permit the steam to be shut off from the remainder of the building in the late afternoon. The divi sion of the building into zones, each with a separatelycontrolled heat supply, is sometimes desirable, as it permits the heat to be adjusted according to variations in sunshine and wind. It is desirable, also, to provide separate lines for water heating and for various cooking or-process appli ances. In oriler that zones may operate at the optimum pressure, it is often advisable to install a separate pressure regulating valve for each. See Fig. 29 of Chapter 26 for typical service installation with separate lines to heating zones and process equipment. The heat supply should be graduated according to varia tions in the outdoor temperature. Because of the continuous availability and constant pressure of district steam, the most economical operation and satisfactory heating can only be obtained by the use of automatic temperature con trol which, except in unusual cases, is well justified. The application of control equipment in various types of build- District Heating 389 Table 4____ Suggested Capacity of Traps Type of Control Trap Capacity, lb/ (Hr) (Sq Ft of Prpa and Radiation*) Continuous or modulating operation, in termittent with on periods over 3 hr in duration Intermittent operation with on periods of to 3 hr in duration Intermittent operation with on periods of hr or less ' M H VfP * Square Feet EDRb Except { drip tnpa on mitira which should be 1 lb pereq ft EDEL ings is fully discussed in the book, Principles of Economical Heating " Various types of control equipment are discussed in Chapter 43. Rapid draining and venting of the heating system should* be obtained by means of suitable traps and air vents in order to obtain rapid circulation and quick heating. This is particularly important with intermittent-type temperaturecontrol equipment. The selection of traps is discussed in Chapter 26. Suggested trap capacities are given in Table 4 of this Chapter. To obtain efficient and economical opera tion of any system it is imperative that all traps be properly maintained. In a system supplied with district steam any leakage through traps may prevent air removal from the system and otherwise impair its operation. Furthermore, such steam must be condensed and its condensate cooled before being discharged to sewer. This represents a direct waste of steam. Provision should be made for conveniently shutting off the steam supply at night and at other times when heat is not needed. A considerable amount of heat can be saved by shutting off steam at night and other times when optimum building temperatures are not required" Equipment is available which will automatically shut heat off at night for varying lengths of time, depending upon outdoor tem perature. _ Residual heat in the condensate should be salvaged. This heat may be salvaged by means of an air-cooling coil, or as is more frequently done, by a water-heating economizer, shown in Fig. 2, which preheats the hot water supply to the building.*1 ` The condensate from the heating system, after leaving the traps, through the economizer. The water supply to the heater passes through the economizer, absorbing heat from the condensate. If the hot-water system in the build ing is of the recirculating type, the recirculating line should be connected between the economizer and the water heater proper, not at the economizer inlet, because the recirculated hot water is itself at a high temperature. Since the heating-system load and the hot-water demand are not coincident a greater amount of heat can be ex tracted from the condensate if storage capacity is provided for the preheated water. Frequently, therefore, the econo mizer coils are submerged in a storage tank. Where con densate is pumped, the pump should discharge into a re ceiving tAnlr equipped with a thermostatic air vent and the -condensate should be permitted to flow by gravity through the economizer and meter. METERING The Condensate Meter was developed for the district heat ing industry and is an approved method of measuring con densate where all of it can be brought to a common point for metering purposes. Its simplicity of design, ease in test ing, accuracy at ail loads, low cost, and adaptability to either high- or low-pressure distribution have made it standard equipment with most heating companies. Condensate meters must not be operated under pressure; 1. Main Return Line from gravity heating system with all re turns properly trapped or pump discharge from vacuum system. With vacuum system a receiving tank with thermo static vent should be provided at Point A. 2. Steam Supply to Water Heater . 3. Hot Water Supply to Building 4. Recirculating Line 5. City Water Line 6. Pressure-Regulator Temperature Control Assembly With Bypass 7. Thermostat Bulb and Tubing Fig. 2 .... Method of installing a Water Heater and Economizer in a Gravity Heating System Fig. 3 .... Condensate Meter Installation Details 390 CHAPTER 27 1959 Guide they are made for either gravity or vacuum installations. Typical meter installations are shown in Fig. 3. In dia gram A a continuous-flow type trap is shown installed ahead of the meter, while in diagram B an intermittent type trap is used. In the latter case, a receiving tank must be placed between the trap and meter to prevent intermittent over loading of the meter. When measuring the discharge from a vacuum pump, a vented receiver should always be in stalled ahead of the meter. Installations of meters in a vacuum return line are shown in'diagrams G and D. In diagram C a master, continuousflow trap is installed immediately ahead of the meter to prevent steam from entering it in case of leaking radiator or fixture traps. Where individual traps are reliable, con nections may be made as shown in diagram D. Flow meters are generally used for measuring sendout from plants, high-pressure requirements in buildings, and in in stallations where all of the condensate cannot be returned to a central point. Further information on flow meters is available from publications of the Fluid Meter committee of the American Society of Mechanical Engineers and from the District Heating Handbook," and are described in Chap ter 4. HOT WATER DISTRIBUTION District heating in the United States is confined almost entirely to the use of steam as the heating medium. Hot water has been used and is being used today, where eco nomic conditions are favorable and good engineering prac tice dictates. ' -' The use of low-pressure hot water distribution below 200 F has been practically discontinued for district heating in the United States because of practical and economic difficulties. The use of high-pressure, high-temperature water distribu tion at 275 .to 400 F has found favor in Europe, where fuel is scarce and is finding some application in the United States* -High-pressure water distribution has some practical and economic advantages over steam (toe Chapter 29 High Tem perature Water Systems). Higher thermal efficiencies, better daily and annual system load factors, lower water treat ment costs, smaller pipe rims, fewer piping accessories, and feasibility of installing pipe to follow contour of ground are given as a few. On the other hand hot water requires a two-pipe distribution system which increases the capital in vestment in some cases. System maintenance is complicated by the necessity to drain at least a portion of the system when connections are made or leaks repaired. . The advantages of hot water have exceeded the disadvan tages in some industrial applications and in Air Force bases in this country.-As the cost of fuel increases, additional ap plications will probably become practicable, especially in new installations serving buildings designed for hot water heat ing.1 REFERENCES 1P. L. Geiringer: Recent developments in high temperature water for area heat distribution in the United States (National District Heating Association Proceedings, 1956). * Steam requirements for processes, maximum demand and load factor (District Heating Handbook, National District Heating Assooation, 3rd ed., p. 346). * Influence of pressure (District Heating Handbook, National District Heating Association, 3rd ed., p. 147). * Effect of looping (District Heating Handbook, National District Heating Association, 3rd ed., p. 155). * American Standard Code for Pressure Piping (American Standards Association, B 31J, 1955, p. 66). 'Steam presure boosters (District Heating Handbook, Na tional District Heating Association, 3rd ed, p. 329). T Graphical Solution of Unxoin's Formula (chart published by the National District Heating Association). For explana tion of chart see District Heating Handbook (National Dis trict Heating Association, 3rd ed., p. 194). 'Gordon Carlson: Improved method of supporting steam pipes in tunnels (National District Heating Association Pro ceedings, 1955, p. 125). 'District beating piping systems, and Fabrication details (American Standard Code for Pressure Piping, American Standards Association, B 311, 1955, Sections 4 and 6). "Piping, valves, fittings and accessories (District Heating Handbook, National District Heating Association, -3rd ed., p. 169). ' . - "Steam traps and drain pockets (District Heating Hand book, National District Heating Association, 3rd ed., p. 175). "Control of steam flow (District Heating Handbook, Na tional District Heating Association, 3rd ed, p. 211). "The reinsulation of underground steam mains (National District Heating Association Proceedings, 1945, p. 21). " Underground insulation specifications. Thermal conductiv ity, Steam pipe insulation, Soil temperature surrounding a buried steam fine, and Heat loss from insulated buried steam line (District Heating Handbook, National District Heating Association, 3rd ed, p. 162, p. 180, p. 184, p. 188, and p. 189, respectively). "Sabin Crocker:- Heat loss (Piping Handbook, McGraw-Hill Boob Co, 1955, 4th ed, p. 1016). . "Return of condensate (District Heating Handbook, Na tional District Heating Asociation, 3rd ed, p. 158). " Reducing and relief valves on consumers' premises (Ameri can Standard Code for Pressure Piping, American Standards Association, B 31.1, 1955, p. 66). "Temperature control (Principles of Economical Healing, National District Heating Association, 5th ed, p. 25). "Hours of heating (Principles of Economical Heating, Na tional District Heating Association, 5th ed, p. 22). "H. T. Kucera: New developments in programming build ing heating (National District Heating Association Proceed ings, 1956). ' " Utilisation of heat in condensate (Principles of Economical Heating, National District Heating Association, 5th ed, p. 40). " Metering (District Heating Handbook, National District Heating Association, 3rd ed, p. 221). " Hot water for district heating (District Heating Handbook, National District Heating Association, 3rd ed, p. 423). CHAPTER 28 HOT WATER HEATING SYSTEMS Features and Design of low Temperature Hot Water Systems; Two-Pipe, One-Pipe, and Series-Loop Systems/ Piping Principles; Circulating Pumps/ Expansion Tank*; Boiler Room Piping; Use of Steam; Temperature Control; System Adjustment; Cleaning Systems HOT WATER heating system is one in which water is 4. The system may generally be designed with a minimum of A used to convey heat by flowing through pipes connect mechanical specialties thereby favoring economical mainte nance. ' ing a boiler or water heater with radiators, convectors, or 5. Due to practical elimination of air, corrosion within the other suitable heat distributing means. The systems discussed system is minimized. in this chapter have supply water temperatures less than 6. Where extended glass exposures occur, the heating ele 250 F and are classified as Low Temperature `Systems. Sys ments, which are relatively large because they operate at low tems having supply water temperatures above 250 F are classified as High Temperature Systems and are discussed in Chapter 29. Classified according to the means of generating temperature, may be well distributed under such exposures to counteract downdrafts. 7.- Quiet operation may be expected in a properly designed and installed system. * flow, hot water heating systems are of two types: the Grav ity System in which circulation of the water is due to the In the design and operation of forced circulation systems, difference in weight between the supply and return water it is necessary to take precautions against any condition that columns of any circuit or system, and the Forced System in would permit the water temperature to fall below freezing, which a pump, usually driven by an electric motor, maintains particularly where coils are used to heat incoming outdoor the necessary flow. - air or where the beating plant may be shut down for more Since the available head or force producing circulation in than 24 hours in cold weather. ' a gravity system is limited, the piping must be of such size If the static pressure in the system is high, it may be neces that the friction loss at the desired flow is not in excess of the sary to use boilers built for operating pressures above 30 available head. prig unless a steam boiler with heat exchanger is used to heat Gravity circulation heads which can be obtained with..vari the water. See discussion in this chapter in section Expansion ous supply and return temperatures are shown in Fig. 1. The Tanks and System Pressure Control. . basic principles which determine design in gravity and forced systems are the same but since the former has less total head available to produce flow, greater precautions are necessary DESIGN OF LOW TEMPERATURE HEATING SYSTEMS in design to secure even distribution of heat with gravity sys tems. Gravity systems are no longer of commercial impor tance. Complete details on the design of gravity type systems are contained in editions of The Guide issued before 1957. Fig. 1 is also useful in determining effects due to tempera The significant factors affecting the design of low tem perature hot water heating systems are discussed in the sec tions that follow. . Heat Loss Calculations ture difference in forced systems when large elevation or tem perature differentials occur. This chapter is devoted to the design of forced hot water systems using supply water temperatures below 250 F. The selection of type of distribution system for heating a particular building should be based upon an objective analy sis of the characteristics of the building, the comfort and temperature conditions required, the system operating and The adequacy as well as the proper distribution of the heat in a building served by a hot water system depends primarily on the proper calculation of the heat loss for the individual spaces and the accurate siring of the heating units to offset those heat losses. Heat loss should be determined in accord ance with the principles discussed in Chapter 12, Heating Load. maintenance characteristics, the space available for piping and equipment, and the economics involved. Selection and Location of Heating Units Information on the types of room heating units available FEATURES OF HOT WATER SYSTEMS for hot water systems will be found in: Chapter 14, Radia Advantageous features of forced low temperature hot wa ter systems are: tors and Convectors; Chapter 30, Panel Heating; and Chap ter 15, Unit Ventilators and Unit Heaters. While the style or type of unit selected for a given space may depend on per 1. The piping need not be run at a definite level or pitch but may change up and down as required by architectural and structural elements of the building. High points should be vented and low points be provided with drain connections. 2. Heat distribution when warming up is uniform. 3. Hot water systems are readily adaptable to simple ap proximate control of capacity and indoor temperature by in struments sensitive to outdoor temperature changes. sonal preferences of the purchaser, the designer should niaka certain that the heat output at the water temperature avail able is equivalent to the calculated heat loss from the space. The heating units within each separately controlled cir cuit should be of similar types, for example: either all castiron or all fin-tube convector-type units. Fan units should noi' be included in a controlled direct radiation zone. The 391 392 CHAPTER 28 1959 Guide radiation should be located at points of maximum beat loss or along outside walls, unless this is impracticable. Determination of Water How Rate The rate of water flow in a system is determined by the heat carrying capacity of the water. This capacity is the product of the .rate of flow, the specific heat, and the tem perature drop of the water as it passes through the heating units. The equation generally used to describe this relation ship is: u - Wc{ti - <*) (1) where B = heat carrying capacity, Btu per hour. W= flow or weight of water, pounds per hour, c ** specific heat of water. <i *= temperature of water entering heating unit, Fahren heit. t, -- temperature of water leaving heating unit, Fahrenheit. The equation may be rewritten as follows for convenient use with Fig. 2. U - Gwc{h - tt) (2) where 0 " rate of water flow, gallons per minute. to - rate of water flow per gallon per minute, pounds per Fig. 1....Heads Resulting from Temperature Difference ' (Gravity Systems) The value of to should be obtained from Fig. 2 for the tem perature at which the rate of flow is determined, and the value of c should be determined at the average temperature. For example: If water enters a heating unit at 210 F and leaves at 190 F, and a water flow of 1 gpm is measured at 190 F, the heat carrying capacity, found by substituting values from Fig. 2 in Equation 2, is H = (1)(484)(1.005)(210-190) - 9728.4 Btu per hr or 9.73 MBh At 60 F the magt flow rate is 500 lb per hr at 1 gpm and the specific heat is very close to 1 Btu per (lb) (F deg). Accord ingly, at a 20-deg temperature drop, 1 gpm will release 10 MBh. This value,' 10 MBh per gpm of water at a 20-deg tempera ture drop, is extensively used throughout the hot water heat ing industry in the calculation of data for low temperature systems. It is considered well within the limits of accuracy of heating system design. If 1 gpm will release 10 MBh at a 20-deg drop, it will release 15 MBh at a 30-deg drop, and 20 MBh at a 40-deg drop. Most low temperature systems installed today are designed on the basis of a 20-deg temperature drop. The temperature drop selected in the design of a system is used to determine the water flow necessary to supply the heat required under conditions of minimum heat loss with supply water tem perature at a maximum value. If the supply.water tempera ' ture is increased at any time, the capacity of a heating unit and the temperature drop of water through the unit is in creased accordingly. When the supply water temperature is modulated according to outdoor temperature, the tempera ture drop of the water in the system is considerably less than the design value during the greater part of the heating sea son. The use of a design temperature drop greater than 20 deg should be considered where large quantities of required ven- Hof Wafer Heating Systems 393 tiiation air are heated hy extended-surface coils, where the required pumping capacity is high, where pumping costs are a critical item, and where extended systems make a saving by the reduction in pipe size possible. Factors considered in selection of a proper temperature drop for a system are (1) the effect of the design average water temperature and water velocity on the capacity and cost of the heating units, (2) the size and cost of the piping, and (3) the initial and operating cost of the pump. Design Wafer Temperature The design supply water temperature is the maximum temperature of the water supplied to the system for the purpose of developing the selected rated capacity of the heating units. ' The design average water temperature of a hot water heating system is the design supply water temperature less Yt the design temperature drop. Capacities of heating units are generally determined oh the basis of the design average water temperature for cast-iron radiation and for baseboard' or finned pipe radiation. Where, a greater degree of precision is required to establish the capacity of heating units, for example, for contract and competitive bidding work, it may be desirable to determine' heating unit capacities on the basis of design supply water temperature and temperature drop through the unit. This is particularly true where the secondary heating surface in the heating element of the unit is a large percentage of the total heating surface, as in con vectors. Design supply water temperatures for radiation systems vary from 180 to 250 F, a common temperature be ing 210 F. Factors considered in the selection of a design supply water temperature are (I) the effect on the capacity of the heating unit, (2) the effect on occupants who may be near the unit, and (3) the greater possibility of boiling as the pressure varies. .. Pipe Sizing Methods The theoretical basis of calculations o.f head loss due to friction of fluids in pipe is the Darcy or Fanning equation, discussed in some detail in Chapter 4, Fluid Flow. Pipe sizes for hot water heating systems are determined most conveniently from .charts such as Figs. 3 to 6 and Table 1 showing pressure loss in relation to rate of flow and size of pipe. Allowance for fittings is generally expressed in elbow equivalents which is the number of 90-deg elbows' that would have equivalent friction toss at the same rate of flow. Fig. 7 and Table 2 are useful in determining the number of elbow equivalents which then may be converted- to equivalent length of pipe by means of Table 3. Figs. 3 to 7 and Tables 1 to 3 are based chiefly on empirical equations developed by F. E. Giesecke in cooperative, research with the Society at the University of Texas and the Engineering Ex periment Station of the Agricultural and Mechanical College of Texas.**1* . The friction loss selected for sizing pipe for a system de pends upon the type of pump used and the economics of small pipe size and high pump head versus large pipe and low pump head. Noise is also an important factor. Velocities are usually limited to a maximum of 4 fps for pipe sizes less than 2-in. to reduce the possibility of noise. Velocities up to 10 fps are frequently used in piping larger than 6-in. Average friction drops of 1.0 to 4.0 ft of water per 100 ft of pipe (120 to 480 milinches per ft of pipe) are commonly used in sizing piping systems. Hie actual friction loss for a 2000wooi KOOOz It eoo-i ,, S0?ri"40 ioo,ooo--io4oo 400- * ,o*M0 200-1 ' : 30400 3400 -2400 2*000; -500 Sa^oo^ -5oo I irS u: *150-; fi ioob ,1- -3.5 *tfioo- roo I 3_ 0.20 '* i 8 500- 1-50 2 " M |2l. ww <x 900.-. -30 Oz Wa aK 9I 200- -20 dIfC 2- ;j c > I 50^"5 * 5 f? 30- -3 . O 3 $ 20-12 % 5 ? cl `i~ V-T < *: I O -0.2 2BASCO ON CLEAN PIPE WITH I4Q F WATER Fig. 3.... Friction Loss Due to Flow of Water in Iron Pipe*'* 1400-5-15 WOO*;: : lio woci 000i K 2 J-14 300-+-2S 23O-.20 30400-^-3400 20400; -2p00 150lOO*-i H- "0 're U2wS*j t24oo-T-a " i* - 30- O 500- -50 _-f * : -|-O.Jg ti 20 2 S I 1 t ^ o -O.5o . w 5- >u uX OO-f-IO o '""i 5u^ 3 ! s 5 rS'- -' * vi _ -0.6 -0.7 *: BASED ON CLEAN TU8IN6 With I4Q F WATER Rg. A.... Friction Loss Due to Flow of Water ' in Type L Copper Tube4 394 CHAPTER 28 1959 Guide particular section of pipe may vary considerably from the average loss for the system due to the limitations of com mercial pipe sixes. For example, if the average friction loss is 2.0 ft of water per 100 ft of pipe (240 milinches per ft), tiie actual friction loss in particular sections of pipe may vary from IX) to 3.0 ft per 100 ft (120 to 360 milinches per ft). One method of siring pipe is based on preliminary selec tion of a pump. The head which the pump can produce is divided by the equivalent length of the longest circuit to obtain an average design friction loss. The equivalent length of a system or circuit is the length of pipe in series flow in the circuit, plus the length of pipe equivalent in resistance to the fittings and also the equip ment in series flow in the circuit. For preliminary calcula tion the equivalent length is sometimes assumed to be 1.5 times the measured length. Table 1 can be used for pipe sizing by this method. It provides the designer with a means for quickly assessing the relative effects, economic and otherwise, of various pumps on the system in terms of pipe rise. . After siring the piping on the basis of a preliminary design friction loss the actual friction loss at design rate of flow FLOW OF WATER IN GALLONS. PER MINUTE . I t.S 2 '3 4 6 a IQ 15 2040 tO >00 ISO 200 *00 coo *000 2000 *0 0000 20000 40000 HEAT CONVEYED PER HOUR IN 1000 BTU ' ` DIFFERENCE IN TEMPERATURE OF WATER IN FLOW AND RETURN RISERS BEING 20F DEG ' Lfliimr 0f chart h based oa 20-dog.toaperotere difference between Sow end return risers. To find (litftoa when temperature ' drop b offior Aon 20 dog. mJltpif A* actual heal conveyed by (20+odual temp, drop) and read tbo comtpondiog fnctioa. Converpoa Ff/OOOH) te MSBnchos/Fl ' R par tOO It 0.5 1 2 34 5 MSfacba* per ft 60 120 240 360 480 600 ' .Fig. 5.... Friction loss due to Flow of Water m Iron Pipe . Hof Water Heating Systems I 395 i - SS2823223 .S3S382SS85 12I512512 82821282 JL *2K2823;S32 g233;iSs2 S2S2S2-S282.S2a28282 i *5*2*3*.ze2 a28Ss;s:s5 352S5S2S" S232S5S2 I 5 I 16 25 47 77 3.4 3.8 4.5 6.2 17 25 48 79 3.5 3.9 4.7 6.3 17 26 50 80 3.6 4.0 4.8 6.5 18 27 62 85 3.8 4.2 6.0 6.7 14 20 39 64 2.8 3.2 3.8 4.3 14 21 40 66 2.9 3.3 3.9 4.4 15 22 42 70 3.1 3.4 4.1 4.7 15 23 45 73 3.3 3.5 4.3 4.8 16 24 46 76 3.4 3.7 4.4 6.0 9.7 14.6 29 47 2.1 2.3 2.8 3.2 11 16 i ; 2.3 17 ^ 11 .2.4 2.7 12 18 36 2.6 2.8 3.4 3.8 13 19 38 60 2.7 3.0 3.8 4.0 1.9 2.2 2.6 2.9 44 1 i27 1.8 1.9 2.3 2.7 38 , 9.0 13 8 3 12.3 24'- L 5 1.8 2.1 2.3 7.3 11 21 32 1.3 1.5 1.8 2.0 6.3 9.3 18 29 1.1 1.2 1.4 1.6 4.8 7.5 14 24 si " "5 ^ I rooo-vnm,,, ' vcoa o -* Jw Ppoc 1 c4oc*^g>~ro.-.o--____ a w a w e w i-w >. ci * ____ c -- r -- ce ~ c- ta - 2 =? - r 2 rownwwwwwwci r- ^ j-g t- .OOOOOOQ^^ --___ pap-pci -- c-< _ c- -- c- cl <n 1 I lllalllllS lilllllSla IsiEiSiSiS lEiSiSlS I J f 8 g 1 I I I 1 i 3 3 1 1 1 I 1 1 1A - s5 04 5 s n s 5 S 3- t g i a i s 1 s 8 8 te 3 T "T 3 TT i sII i35 33S s - i-i 1 I s i B i 3 g 2 3 2 1 I " - s 8 'I g a 1 8- 5 1 3. S 3 8 S S 8 g i s 8 8 S I 2- j 3 2 i i i12j 1* 2 2 1 M- i i 8$ - i 81I 3B Ig SS31I 1M I 1 1iS .s i E 1 S iS1 1gi11 s11SI SS18 i1S1 s 1 8 83118I 118 a 12ig a. i i i s -8 g _ 1 iI 2 s 2 8 s i K I S S 1 5 8 i 6 2 1 1 i M 8 1 1 g 5 5 1 3 i g .1 8 1 s a 1 8 1 s I B i 5 S-3 S3 1 e s 2 1 1 i i. 8 E 8 1 s S 1 3 3 8i g 1 1 = 1 I i g S 1 8 1 i I-!- 8- 1 1 5 i 1 1 1 i I i i g i 3 1 396 CHAPTER 28 1959 Guide Lower scale of chart it on 20-dog tomporatvro difference between flow and return risers. To find friction when temperature . drop is other than 20 dog, auMpiy the adtiat heat comwfed by 120-roctoaf temp. drop) end rood fi>* corresponding friction. . Conversion Ff/(I00 ft) to Alifioches/ft . Ft per 100 It 0.5 1 2 3 ' 4 5 MiKnches per ft 60 120 240 360 480 600 Fig. 6.... Friction Loss doe to Flow of Water in Type L Copper Tube Table 2 .... Iron and Copper Elbow Equivalents*.......... fitting Iroa F|p* Copper Tubing 1.0 0.7' ' 0.5 0.5 0.4 1.0 2.0 3.0 3.0 0.5 12.0 * See-Teble S lor equivalent length of one elbow. 1.0 0.7 0.5 0.4 1.0 3.0 4.0 4.0 . 0.7 17.0 should be calculated. The friction loss at design flow for, all individual sections of pipe and for all fittings in the longest piping circuit should then be summarized. Table 2 shows the number of elbow equivalents for various fittings. These equivalents can be converted to equivalent feet of pipe by use of Table 3. Fig. 7 shows the elbow equiva lents for determining friction loss in tees. If the pipe size calculation indicates a required pump head different from that of a standard pump, pipe sizes in the system may be changed to establish a closer relationship between the two. The relationship between systems and pump heads is dis cussed in the section Circulating Pumps. If there are more circuits than one in a system, the fric tion loss for the longest circuit should be used to determine Vet. fpt 5 6 8 10 Table 3.... Equivalent Length of Pipe for 90-Deg Elbows . Pip* Size X H 1 ix IK 2 2M 3 1.2 1.7 2.2 3.0 3.5 4.5 5.4 6.7 1-4 1.9 2.5 3.3 3.9 5.1 6.0 7.5 1.5 2.0 2.7 3.6 4.2 5-4 6.4 8.0 1.5 2.1 2.8 3.7 4.4 5.6 6.7 8.3 1.6 2.2 2.9 3.9 4.5 5.9 7.0 8.7 1.7 2.3 3.0 4.0 4.7 6.0 7.2 8.9 1.7 2.3 3.0 4.1 4.8 6.2 7.4 9.1 1.7 2.4 3.1 4.2 4.9 6.3 7.5 9.3 1.8 3.2 4.3 5.0 6.4 7.7 9.5 1-8 2.5 3.2 ' 4.3 - 5.1 6.5 7.8 9.7 3K 7.7 8.6 9.2 9.6 10.0 10.3 10.5 10.8 11.0 11.2 4 8.6 9.5 10.2 10.6 11.1 11.4 11.7 11.9 12.2 12.4 5 10.5 11.7 12.5 13.1 13.6 14.0 14.3 14.6 14.9 15.2 6 12.2 13.7 14.6 15.2 15.8 16.3 16.7 17.1 17.4 17.7 8 15.4 17.3 18.4 192 19.8 20.5 21.0 21.5 21.9 22.2 10 18.7 20.8 22.3 23.2 24.2 24.9 25.5 26.1 26.6 27.0 12 22.2 24.8 26.5 27.6 28.8 29.6 30.3 31.0 31.6 32.0 Hot-Water Heating Systems the pump head requirement.. Pining in the other circuits should be sized to obtain the same total friction loss. Effect* of Antifreeze Fluid*. Antifreeze solutions are some times used in heating systems when the danger of freezing exists. They should not be used in direct-fired boiler applica tion. Corrections must be made in flow rates, pipe size, and pump capacity relative to water when antifreeze solutions are used. See Chapter 49, Snow Melting. SaECTlON OF PIPING ARRANGEMENT .The type of distribution system selected for any particular building will depend primarily on the structural and archi tectural characteristics of the building, the need for separate control of different zones, the pressure head due to the height of the building, the space available for piping, and the rela tive cost of different arrangements of piping. Consequently, mains may be run in basement, separate floors, or in space above highest heating units. There are four distinct arrangements of main piping: (1) the two-pipe reversed-retum system, (2)'the one-pipe sys tem, (3) the series-loop system, and (4) the two-pipe direct return system. The last is not recommended unless elaborate pipe sizing technique and provision for adjustment are em ployed. Two-Pipe Reversed-Retum System--Description and Design . The two-pipe reversed-retum main system. Fig. 8, has two mains, one supplying water to the heating units or to risers 397 to heating units, and one collecting water returned from these units. The piping is arranged in such a manner that the sum of the equivalent length of supply and return piping to any unit is approximately equal to that of any other unit. Compared with a one-pipe system, the two-pipe system may: 1. Have a smaller average pipe size. While two mains are re quired, the sizes of the mains vary as water passes from one main through the heating unit to the other. The maximum size of either main is no larger than the size of a one-pipe main. 2. Be more flexible in its application because-larger friction loss may be used in the heat-transfer unit circuits. 3. Require a minimum pumping head because the heating unit resistances are in paralleL 4. Permit adjustment of flow through individual units of ra diation over wider limits. Fig. 8.... A Two-Pipe Reversed-Rehim System Notes: I. The chart it based oo straight tees, that it, branches A, 6, and C are (he same rise. . Head loss to desreddranl isobtamed by wtecfmg proper curve accord<*>8 to Sfasfroffoas, determining the flow at the ctrded branch, and auttjptyfog Ibe head loss far the same axe elbow at the flow rate m (he arded branch by Hie equivalent elbows indicated. 3. When the site of an oattet it reduced the equivalent betbows shown hi the chart do not apply. The maximom toss for any drew! for any Aow wifi not exceed 2 elbow equivalents at file maximum flow (gpm) occurring tn any branch of the tee. 4. The top curve of the diarf is the average of 4 curves, aae far oedi of he tee drrurii {Oustrated. Fig. 7.... Elbow Equivalents of Tees at Various Bow Conditions*- " Continuing the comparison, some disadvantages are: . 1. Two mains may require more pipe fitting labor t-hn a single main. 2. Some additional pipe may be required to achieve a re versed return. ' 3. A two-pipe system will be slightly more expensive for email systems. 4. The piping for two mains may be unsightly in occupied spaces. ' Important considerations in the design of a two-pipe reversed-retum distribution system are: 1. The head which the pump must generate is equivalent to the friction drop through the circuit having the highest resist ance. At design flow, the resistance through the distribution r' im to any one heating unit should be the same as that ugh any other unit. Where the length of pipe required to obtain distribution to a particular section must be shorter than to other sections, it is desirable to design that section with a higher friction tos. ' 2. A reversed return, as indicated in the section Adjustment of Flow and Capacity, will reduce the need for adjustments neces sary to obtain equal total head through each heating unit cir cuit. . 3. Fan-type air-heating units with extended-surface coils can be used with a higher water temperature drop than that recom mended for direct radiation. It is necessary to avoid a difference . in air temperature across the face of the coil in.such units. One method of minimizing this difference is to install a minimum of two serpentine coils in each unit, one in front of the other. Coil 398 CHAPTER 28 1959 Guide connections are so that water travels from top to bottom in one coil and from'bottom to top in tlie other.. The design'of a two-pipe reversed-return system will be illustrated by Example 1. ' Example l: Design a two-pipe reveraed-retum hot water heating system for a 37 x 29 ft one-story residence with basement having a beat loss of 50 MBh (50,000 Btu per hr). The beating units are to be convectors operating with a supply water tem perature of 210F and a 20-deg temperature drop. The piping layout and location of convectors are shown in Fig. 8. . Solution: A 50 MBh load with a 20-deg drop requires a water circulation of 5.gpm. The length of the reversed-retura circuit is determined as 138 ft of pipe, by following the supply from the boiler to point Q Fig. 8 and the-return from point N back to , the boiler. The estimated total equivalent length is 138 X 15 = 207 ft. This, plus an allowance of the equivalent of 25 ft of pipe for one convector circuit results in a total equivalent length of pipe of 232 ft. Fig. 9 shows that a 1-in. pump has a capacity of 5 gpm at 4.7 ft available head. The preliminary average design friction loss is then 4.7 X 100/232 or 2 ft per 100 ft of pipe (240 milmMw per ft). Ibis value can also be determined t>y refer ence to Table 1, where, nng the vertical column under 5 ft, the next larger equivalent length to 232 ft is 250 ft. To the right in this line read the average design friction las as 2.ft per 100 ft or 240 milinches per foot. ' The piping may be sized initially from Table 1 as follows: In the friction loss column find the value 2 ft per 100 ft. Proceed to right in the same line to the nearest gpm value and then read the pipe sise at the top of the column. ' The pipe sizes found by this method for the various sections of Fig. 8 are shown in the following table: Section Supply MBh Gpm Pipe Size A-B B-C C-D D-E E-F F-G G-H 50 43.5 36 30 .. . 25 18 8.2 5.0 4.35 3.6 3.0 - 2.5 1.8 0.82 1 1 X H X H a w J-K K-L L-M M-N N-O O-A Return 6.5 14 20 25 32 41.8 50 0.65 1.4 2.0 2.5 3.2 4.18 5.0 X X K X X' .i l The risers to the convectors may also be sized for the same average friction loss, 2 ft/100 ft or 240 milinches per foot, ss follows: . ; Convector Ho. 1 2 3 4 5 6 7 Load MBh.... 6.5 7.5 6.0 5.0 0.65 0.75 0.60 0.5 Pipe size......... X X X X 7.0 9.8 8.2 0.7 0.98 0.82 HXX After the initial pipe sizes have been selected the friction loss in the system should be recalculated as indicated in the following table, 'the highest pressure drop circuit shouldbe marked off into -sections; ne/rh of a different Sow rate. The total equivalent length of each section should then be determined by adding its elbow equivalent length (see Tables 2 and 3 and Fig. 7) to its actual measured length. Total friction loss is established from charts or tables for each section by multiplying its total equiva lent length by the actual friction loss per foot at design flow. The circuit friction pressure drop is the summation of individual section pressure drops as shown in Table 4. If the total friction loss as determined does not agree with the pump head, some pipe size changes will be necessary to obtain closer agreement. The slight difference in head calculated by milinches and by feet of head is due to use of only 2 significant figures for the latter. This is well within the accuracy required. As would be expected the calculated head of 4D2 ft is differ ent from the 4.7 ft estimated. This is due to two factors: (I) the difference between the actual and estimated number of fittings and (2) the differences between actual and estimated losses m the different sections as the friction losses were generally below the average friction loss assumed. The Inn. pump initially selected would be entirely satisfac tory for the installation and would produce a flow slightly in excess of 5 gpm. A procedure to determine the actual flow and capacity of the pump and system is discussed under Cir culating Pumps. One-Pipe System, Description and Design The one-pipe system, Fig. 10, has a angle main for both supply and return. Special fittings installed at the connec tions to radiation risers or runouts generate the head neces sary to produce flow through the heating unit. In this sys tem the main or circuit loop does not change size from the first to the last radiation unit. The amount of water flowing in the TM*in is constant, except at points where some of it is bypassed through radiation. Since the water temperature in the main drops progressively, some designers consider it necessary to increase the size of beat-transmitting surface accordingly by using a progressively lower design water temperature in sizing the heating units. Most one-pipe heat ing systems are designed, however, on the basis of a single design water temperature. Generally, the theoretical in crease in heat-transmitting surface is needed only when the system is operating at full design output. A water tempera ture drop in the main of 20 deg or less minimizes the ca pacity reduction effect. In comparison with a two-pipe system, the one-pipe sys tem: 1. Permits simpler piping due to the use of one main of uni form size. 2. May be more acceptable when pipe is exposed in occupied spaces. ,, 3. Is very adaptable to small systems or to individual loops Hot Water Heating Systems Table 4.... Calculation of Actual Friction Loss for Example 1 flev MBh Gp- friction lots (fig. 3) Ft/lOOFt Mi/R fipo Sat la. (fig. 3) fitting* Type Total Pip* Egwv length ft Laagth of Eqorv ft* ffeeft friction Ion Cokdafim . Mi* BC . 43.5 1.5 1 4.35 180 1 ell 2.4 14 16 0.16 X 1.5 16 X 180 2880 CD 36.0 1.0 1 3.6 120 -- 15 15 0.15 X 1-0 15 X 120 1800 DE 30.0 2.5 X 1 ell 3.0 300 1.9 8 10 0.10 X 2.5 10 X 300 - 3000 EF 25.0 1.8 X 2.5 210 -- " 10 10 0.10 X 1.8 .10 X 210 2100 FG 18.0 1.0 X 1.8 120 -- -- 14 14 0.14 X 1.0 14 X 120 1680 GN 9.8 1.2 X 3 ells 0.98 150 1 X m* tee 1 1 in. tee 1 Rad. V 3.6 8 23 0.23 X 1.2 3.4 23 X 150 3500 4.8 3.6 NO 41.8 1.4 1 1 ell 4.18 170 . 2.5 31 34 0.34 X 1.4 34 X 170 5780 OB 50.0 1.9 1 3 ells 5.00 230 2 tees' 7.5 38 116 1.16 X 1.9 10.0 116 X 230 26700 2 Gate valve 2.5 1 Flow valve 50.0 1 Boiler 7.5 Convector friction loss*................................ 1200 Total friction lot Data obtaised Iran manufacturers' catalog. b Sec aho Tabtei t and Z and Fig. 7. 48590 399 ' R 0.24 0.15 0.25 0.18 0.14 0.28 0.48 2.20 0.10 4.02 in large systems, either horizontal or vertical, as a part of a two- pipe system, or to obtain zone control in large combination sys tems. '. 4. May be lower in installation cost. 5. Has a simpler problem in regard to water-flow adjustment. : Continuing the comparison with two-pipe systems some disadvantages of one-pipe systems are: . . 1. The amount of water which can be bypassed by a one-pipe fitting Or fittings is limited by the economics of design and the head applied. The fittings are not generally used to provide the water now necessary for Large air-handling units having a high pressure drop. - .. 2. The pump head required is slightly higher than that re quired for a two-pipe reveraed-retum system of eimilar flow re quirements. . 3. If the progressive increase of radiation size as temperature drops is taken into account, a design complication and additional cost factor are encountered. 4. The main flow design temperature drop should not exceed 20 deg. Design of a One-Pipe System The basic design premise of a one-pipe system is that the pressure drop of the one-pipe fitting, or fittings, at the re quired main flow, be equal to or greater than the radiation circuit pressure drop at its required flow. The system may be divided into two or more loops for Wnallnr main pipe sizes and pumps. Main and radiation circuit temperature drops may be different. For example, a 10-deg temperature drop may be used in the main with a 20-deg drop through the radiation. Example t: A one-pipe system is to be designed for the resi dence discussed in Example 1. Fig. 10 shows the piping arrange ment for the one-pipe system. The size of the convectors is determined on the basis of a 210 F design supply water tempera ture and a 20-deg temperature drop as in Example' 1. Solution: For initial selection of pump use a 1-in. pump hav ing a capacity of 5 gpm at 4.7-ft head. The measured pipe length is 140 ft which establishes an equivalent length of 140 X 15 = 400 CHAPTER 28 1959 Guide 210 ft. The preliminary design friction loss is then found in Table 1, as in Example 1, to be 2/* It per 100 ft or 270 mi per ft. At thin average design friction loss (see Table 1) a 1-in. main will be used for the required flow of 5 gpm. . From manufacturers' data at 5 gpm flow, the pressure drop from a 1-in. fitting is established at 3000 mi or 025 ft. If any heating units are located below the main the gravity head due to temperature difference should be subtracted from available fitting pressure drop. In this example, the riser and convector friction pressure drop should not exceed 3000 mi or 025 ft. The friction loss through the 14-in. risers to the 9 MBh convector was calculated to be 028 ft or 3450 mi in Example 1. This loss plus the 0.1-ft (1200-mi) loss in the convector, equals - 0.38 ft (4650 mi) which exceeds the capacity of the fitting. If 94-in. risers are used, however, the riser pressure drop is con siderably reduced. For 92 MBh flow the pipe friction drop is 024 ft for 100 ft (40 mi per ft). The equivalent length changes from 22 to 26 ft. The riser pressure drop is then 26 X 034 or 0.09 ft (26 X 40 or 1040 mi). The head loss through the convector circuit is then 0jQ9 + 0.1 or 0J9 ft (2240 mi). Since this is be low the available fitting pressure drop, the riser size is satis factory. - . Other upfeed risers are sued in a similar manner. The piping to the 62 MBh convector below the main is sized as follows: - The water in this circuit will cool to room temperature during . off periods. The center line of the convector is fiVi ft below the mam. The thermal head opposing circulation in the convector circuit when one riser is filled with. 210 F water and the other... . has 70 F water is found to be 465 mi per ft or 465 X 53 -- 2560 mi total. Subtracting 2560 from the 3000 mi pressure drop in the fittings leaves 440 mi available to start circulation. The com bined convector and riser pressure drop equals 1380 mi even when a 1-in. riser is used. Since the convector and riser pressure drops are greater than the available fitting pressure loss, a change must be made. The total fitting pressure drop could be increased by adding a supply one-pipe fitting, or by increasing fitting pressure drop through use of a larger pump. In thin case, the riser is sized on the basis of an added fitting. In accordance with the sizing procedure followed in this example, a 94-in. riser is adequate. ' The pipe sizes selected should be recalculated at the design flow rates either in milincbes as shown in the upper part of tie following table or in feet per hundred feet as shown in the lower part of the table. Section Pipe Site In. hood MBh Lots per fool of Pipe Mi lettgffe -ft Total Friction Elbow Total loss Mi* quirements of the system based on the assumptions stated for the problem. Series-Loop System--Description and Design This system, illustrated in Fig. 11, consists of one or more loops or circuits. In each circuit, as the same water is circulated through the heating units in succession, the size of pipe should not vary materially in any portion of a circuit. The system circuit length thus becomes very important be cause it influences directly the water flow rate, pressure drop, and temperature drop. Since the water temperature in each successive heating unit decreases progressively, some de signers consider it necessary to increase progressively the size of heating units sufficiently to compensate for the drop in temperature. If a grnfl-H design temperature drop, such as 20 deg or less is used, it may not be necessary to increase the hwating units in size toward the end of the circuit. Various considerations affecting the design of a series-loop system are given in the following paragraphs: ' Main. .. 1 50 240 140 $7b 227 54,500 24,000 78,500 6.55ft Length--ft Section ftp* Size In. load MBh 700 Ftiof Pipe Ft Linear Elbow Total Total Lon ft Pipe Main. .. 50 2.0 140 87b 227 4.54 8 one-pi) >e fittings at 0.2.5 ft head 2.0 6.54 * JO v tntliiu>hi* ' .. b The elbow equivalent length is based on: S elbows, 1 tees, J gate valves, 1 6aw check valve end 1 better. ` * The actus! value (or remtaaee of the one-pipe fittings should be obtained (rum the fitting manufacturers. They are frequently lower than the value as sumed in this ' 1 The'pump rapacity required is 5.0 gpm at 624 ft head. The 1V4 in. pump.as shown in Fig. 9 would meet the re 1. It may be posrible to eliminate all or large sections of the distribution main and thereby reduce cost. In large buildings it may be necessary to use a partial two-pipe main in combina tion with the series-loop system for certain sections or-divisions of the building. 2. The practicability of the system will depend upon the quantity of water to be circulated through the heating units and the friction loss. Baseboard or finned-type pipe elements for series-loop systems are usually manufactured from standard steel pipe or copper tubing. The friction loss can be determined from Figs. 3 and 4. 3..If a series-loop system serves more than a single space, and if the design temperature drop for the system is in excess of 20 deg, the size of the heating unit should be determined on. the basis of the temperature of the water entering the particular heating unit and the temperature drop across the unit. The tem perature drop through a particular heating unit is equal to the capacity of that unit divided by the capacity of the total radia tion circuit multiplied by the total temperature drop of the circuit. 4. Since the temperature of the water supplied to heating units in the series-loop system cannot be regulated, it is ad visable to provide dampers in the cabinets containing finned pipe-or baseboard radiation to permit adjustment of the heat delivery by each unit. Valves or adjusting fittings, if used in the water circuit, would affect the performance of toe entire loop and would not -be a satisfactory means of controlling the heat output of the units. fHot Wafer Heating Systems 401 Certain of the series-loop system are: 1. The difficulty of making suitable provision for adjustment utnrf balancing of the system. - 2. The total circulating head required may be excessive. 3. The da-q?gn of the system may be more difficult than for one-pipe ot two-pipe main systems. - Example S: A series-loop system is to be designed for the .residence used in Examples 1 and t for two-pipe and one-pipe design. No heat will be supplied to the basement. The total heat loss equals 45,500 Btu. Baseboard-type radiation having a rating of 05 MBh per linear foot at an average temperature of 190 F, is selected as the radiation used. The heating, units are of baseboard type having a rated output of 05 MBh per linear foot at an average temperature of 190 F. They are connected by 94-in. pipe. A 20-deg design' temperature drop will be used. Solution: For a 455 MBh load 455 gpm must be circulated for a 20-deg temperature drop. For a single looped main the measured length equals 140 ft. The approximate equivalent length equals' 140 X 15 or 210 ft. If the lV4-in. pump, Fig. 9, were initially selected, it would develop a 6-ft head at 455 gpm delivery. For an available head of 6 ft and an equivalent length of 218 ft (nearest to 210 ft) Table 1 shows that only 3 gpm will circulate through the 94-in. main. A larger, and more costly pump may be tried. The 3-in. pump. Fig. 9, has 12.7 ft available head at 455 gpm delivery. Ii 12-ft available head and 250-ft equivalent length are used as the. nearest available values. Table 1 indicates that a flow of 43 gpm at a velocity of 25 fps will be established through the 94-in. main. However, because of cost, appearance, and temperature drop considerations, this may not be desirable. If the system is divided into two loops, as shown in Fig. 11, a smaller pump may be used and the system temperature drop decreased. ' The lV4-in. pump at 6-ft head for 455 gpm is again selected for preliminary sizing of piping. The measured supply main length plus the length of the long est loop circuit is 106 ft. The equivalent length equals 106 X 15 or 159 ft. For 6-ft available head and 160 ft equivalent length, Table 1 indicates that the friction loss would be 394 ft per 100 ft or 450 mi per ft. At this friction loss toe supply main would be of 1-in. size for a flow of 7 gpm (which is more than the re- ?uired 45) and the 94-in. looped main would deliver 3.7 gpm more than toe required 225 gpm). Because the flows are'rnore than required, the system temperature drop would be les than 20 deg. A smaller pump could therefore be used if desired. The pipe sizes should be recalculated at the design flow rates as follows: ' s"""' Heot Dedgo Pipe ftLood MBh Row Gpm ft/700 Size to. ^ft Total Press ft ftDrop AB 45.5 4.65 m 1 36.0* 2 elbows 2 gate valves 1 flow valve 1 boiler - 5.0 2.5 50.0 7.5 . 101' 1.77 BCA .22.5 | 2.25 | 1H | H . 70* 8 elbows . 1 cock 2 tees @ 50% . 13.6 - ' 1.7 . 13.6 99 1.5 Total........................ ...................................................... 3.27 * Actual pipe length. Since the total system bead less equals 327 ft at a flow of 455 gpm and the lV4-in. pump is a satisfactory selection. If desired, the actual design temperature drop can be deter mined. Because the pump head at 455 gpm is greater than 327 ft, the flow in the system will increase until pump head and flow equal system pressure drop flow. Construction of a system curve, as described under centrifugal pumps, shows that for the system with the pipe size selected and with toe 114-in. pump, equilibrium will be reached at 6-ft head and 62 gpm flow. The actual temperature drop for design conditions would then be (45/62) X 20 or 145 deg, approximately. Combination Systems Three types of systems have been illustrated, namely: one-pipe, two-pipe reversed-return, and series-loop. Actually the design for a particular building may be a composite of two or even all three of these types of systems. For example, a two-pipe reversed-return system of distribution may be used with a number of one-pipe loops in a single building such as an apartment house, or a two-pipe reversed-return system may be used with a main riser at each end of a build ing with a series-loop system used to serve the space on each floor of the building. In any case, it is well to bear in mind the principles of design involved in each particular type of system for that portion of the installation where it is used. -Adjustment of Row and Capacity Where the hp-ating elements and piping are properly sized and arranged, a hot water system is, to a large ex tent, self-adjusting. This is so because the mean tempera ture of the water flowing inside the heating unit is the most important factor in determining .its output. If the flow of water is within 5 to 15 percent of the correct value for a given hparing unit, the difference in mean temperature will not exceed 1 or 2 deg and, consequently, the effect on heat output will be negligible. However, the limitations of com mercial pipe sizes and pipe arrangement sometimes result in flow rates considerably different than those required to develop the proper output of the heating units. A means of adjusting the heat output of heating elements and branch circuits must be provided in-the system to correct these effects. Adjusting means may be necessary due to the type of sys tem, for example, the two-pipe system using direct-return mains. In this system the water flow circuits are hydrau lically unbalanced, because the water for the first heating load taken off the main is the first to be returned. As a re sult, the first heating unit will' receive a much greater flow than is required to develop its rated output. The flow through the last heating unit can be so low that practically no heat is delivered. The poor distribution of flow in the direct- return system can be corrected-, by the installation of orifices or of adjusting fittings or -valves, by means of which the system-is balanced after it is placed in operation. In some cases, proper flow distribution can also be established by careful pipe size selection. That is, the piping can be sued so that the pressure drop through each piping circuit is the same at the design flow rate. - These troubles are minimized by the reversed-return sys tem, Fig. ,8. In this system the water for the first heating load taken off the ream is the last to be returned, and all circuits' are of approximately equal length. Proper hy draulic balance is therefore easily obtained and the system is inherently self-adjusting. While the reversed-return piping circuit is much preferred, in some large installations a saving in pipe can be effected by use of a direct-return system. When selecting the type of piping arrangement-such as one-pipe, two-pipe, series-loop, upfeed, aad downfeed, the 402 CHAPTER 28 1959 Guide adaptability of each arrangement for-proper hydraulic bal ance should be considered. Air Elimination If air and various other gases which occur in hot water hooting systems are not eliminated from the flow circuit, they may collect in the heating units , or piping and reduce the flow of water and the heat output. These gases, desig nated oirih this text, are in the piping before it is filled with water, are introduced with the water used- to fill and replenish the system, and also are formed to a limited de gree from chemical action inside the system and from the movement of low temperature air-saturated water from the fig. 12....Typical Automatic Air Vent Valve Installation expansion tank to the system " Loss of air by absorption in the water may be prevented by a flexible diaphragm pre venting' contact of water and air in the expansion tank and having adequate movement to permit the expansion of the water in the system. .- The air is eliminated from the flow circuits by trapping it into the expansion tank as explained in connection with dis cussion of dtp tithes in the section Boiler Room Piping and piped to a drain to prevent building damage and facilitate inspection for leakage. Automatic air-vent valves should not be instAlled in piping where temperatures in excess of 215 F can occur without careful analysis of possible temperature- pressure effects. . unit of radiation which _ act as an air trap should be provided with an air chamber and air-vent valve (Fig. 13). The use of manual air-vent valves or porous plug- or disc-type manual-automatic valves is recommended for radiation. Piping Principles Piping should be pitched up in the direction of flow in all cases when pump operation is constant, and wherever pos sible when pump operation is intermittent to assure con sistent air elimination during conditions of other flow or no flow. Piping is pitched Vi in. per 10 ft as standard practice. When changing the gige of pipe in horizontal runs, ec centric reducers should be used to keep the top of the pipes in line. A nuans of manual capacity adjustment should be pro vided for each heating unit. Manual valves or adjusting cocks are frequently provided for this purpose. Dampers at the heating element or at the outlet of convection-type units may be used. Hie heating unit located in the area of a zone thermostat should be equipped with a key-operated adjusting device to discourage tampering by unauthorized personnel. The piping should be installed to provide for thermal ex pansion of the pipe without imposing undue stress on con nections or equipment. Spring pieces of sufficient length, as required by the diameter of the runout and the amount of expansion to be absorbed, should be installed at connections to radiators and risers. Expansion joints or loops and prop erly located anchors should be used where required. See Chapter 31, Pipe, Fittings, Welding. All maina and risers located in exterior walls should be covered with sufficient insulation to prevent freezing. Trunk mains running between buildings must be protected by con duit or installed in trenches below the frost line and properly insulated. When heating mama are run in locations where they could possibly be immersed in water, the conduit should be watertight. - fig. 13....Typical Air Vent Valve Installation on Heating Element by the installation of manual or automatic air vent valves at all high points in the system. . Automatic air-vent valves may be used to eliminate air from the mains and major equipment. Lake other mechanical devices, they are subject to malfunction. Small pieces of dirt or scale can lodge on the valve seat, causing it. to leak. Corrosion, scale, or sludge in the valve can prevent the valve from opening to eliminate air. All systems should be designed to have a minimum number of automatic air-vent valves, but where a valve is required there should be no hesitancy about using it. In large systems where large numbers of automatic air-vent valves are necessary, provision should be made for service of each valve-without draining the system (Fig. 12). The drip from each air vent valve should be Grculating Pumps Circulating pumps used in hot water heating systems can vary from small M*hp booster-type pumps with a ca pacity of 5 gprn at 6- or 7-ft head to pumps handling hundreds, even thousands, of gallons per minute at heads limited only by the pressure characteristics of the system. The selection of a pump for a system is based on an analy sis of operational characteristics of the pump and system. Both first cost and operating cost are involved. See dis cussion under Pipe Sizing Methods, Expansion Tanks and System Pressure Control. Pumps with mechanical seals have found wide acceptance in hot water heating. Pump characteristics, as affected by system characteristics, should be given consideration to insure non-overloading conditions in pump motor operation. Any given pump, when operated with a given fixed-head system, will operate at only one point on its curve, the inter section of the pump curve with the system curve. Pump curves may be obtained from manufacturers. System curves can be constructed by plotting head versus gpm for dif Hot Water Heating Systems 403 ferent flow rates. The head for various flow rates can be' estimated by use of the equation: where Hi = calculated system head. Hi -- head at new flow rate. Gi *=* calculated flow rate. Gt ~ assumed new flow rate. complish system pressure control. The excess water volume in the system resulting from increased temperature is stored in the expansion tank during periods of high operating tem peratures and returned to the system when the system water temperature is lower. The expansion tank must be designed to store the required volume of water during maximum de sign operating temperatures without exceeding the maxi mum operating pressure allowable, and to maintain required minimum pressure when the system is cold. Some designers provide an automatic fill valve.to maintain thp minimum For economic or for operational reasons two simitar pumps are sometimes used in parallel on a single circuit. When so used the combined pump curve showing the relationship of flow to head due to operation of both pumps is established by adding the flow capacity of one pump to the flow ca pacity of the other at identical heads. If two pumps are placed in series, the relationship'of flow to head due to operation of both pumps is established by adding the pump heads at identical flows. When' using pumps in series, they must be identical or similar since the maximum flow will be limited by the smaller pump. Gate valves should be pro vided to enable isolation of either pump when only one is in operation. The Heat Source or Boiler The most frequently used source of heat is the 30 psi hot water heating boiler, constructed of cast iron or steel in ac cordance with the ASME Boiler and Pressure Vessel Code, Section IV for Low Pressure Heating Boilers. See Chapter 35, Heating Boilers, Furnaces, Space Heaters. Boilers, classed as low-pressure heating boilers, may be-used for hot water with pressures as high as 160 psig if the temperature of the water does not exceed 250 F and if they are con structed according to the ASME code for the pressure at which they are operated." The ASME code requires installation of a relief valve'on each hot water heating boiler to limit the pressure exerted on that boiler to the value for which it was designed and tested.*4 Similar requirements exist for converters and elec tric water heaters. This operating pressure limit for the boiler is an important factor in the.design of the hot water heating system. Together with" the size and characteristics of the expansion tank, it determines the permissible height from the boiler to the top elemgnt or pipe of the distribution system, as discussed under Expansion Tanks. In addition to the pressure relief valve required by the ASME code, a hot water heating boiler should be equipped with a ther mometer, located at or near the top of the boiler, and a reliable pressure or altitude gage with a range at least twice that of the maximum operating pressure or altitude allow able for the boiler. N ENT V Expansion tank n- SION I fig. 14.... An Open Expansion Tank EXPANSION TANKS AND SYSTEM PRESSURE CONTROL The objectives of system pressure control are to limit the pressure at all equipment in the system to the allowable working pressure of the equipment; maintain minimum pres sure for all normal operating temperatures in order that air can be vented and cavitation at the pump suction and boiling of system water prevented; and accomplish these objectives with as little addition of new water to the system as possible. An expansion tank is the primary device used to ac pressure in the system by supplying water to make up for losses due to leakage. Others prefer that water added to the system be supplied by a manually operated valve. The relief valve installed on a hot water boiler in ac cordance with the ASME code performs the function of limiting the maximum pressure at the boiler. Since it is a safety device, it should not be considered ah operating control. Systems are designated as open (Fig. 14) or closed (Fig. 15)- . ... The open tank system is vented to the atmosphere and is generally limited to installations having operating tempera- i 404 CHAPTER 28 1959 Guide iuies of IK) F or Icgs because of system boiling and tank water evaporation problems. The tank should be at least 3 ft above the high point of the system and should be con nected to the suction side of the pump to prevent subatmospheric system pressures caused by pump operation." The system should have an internal overflow drain. Pro vision must be made to prevent water from freeling in the tank, the tank vent, and the pipe leading to the tank. These provisions are also required by the ASME code. The mini mum kwilr volume should be equal to 6 percent of the total system water volume. The closed system utilizes an airtight tank which provides a of pressurizing the system for operation over a wide range of conditions. As the excess water due to thermal expansion moves into the expansion tank, it compresses the air trapped therein and increases the pressure on the system. If the tank, or the amount of air in it, is too small, the pressure on the system will exceed the maximum allow able, and'cause the relief valve to waste water from the system. When the system cools, the pressure will drop to a value lftsa than minimum, making the venting of air im possible or drawing air into the system if automatic air vent valves are located at a high point of the piping. If the tank is too large, it will cost more and require more space. Determining Tank Size The size of a closed expansion tank is determined by: volume of the water in the system; range of water tempera tures normal to operation of the system; pressure of the air in the expansion tank when the fill water first enters the tank; relationship of the height of the boiler which usually, but not always, is the item in the system with the lowest working pressure; the expansion tank, and the high point of the system; head of the circulating pump; location of the circulating pump with respect to the expansion tank con nection, and the boiler. The expansion tank size for a closed Table 5.... Volume of Woter in Standard Pipe and Tube Nosunel Pep* Six* fndw< H K Hs i lK 1H 2 2H 3 3K 4 5 6 8 10 12 Standard Steel Pep* Type L Copper Tufa* Sch*<te>* No. _ 40 __ 40 Indd* Did _ --0.622 0.824 Gottorn p*r Un. Ft _ 0.0157 -- 0.0277 inside Dio 0.430 0.545 . 0.666 0.785 GoHorn Pf Un. Ft 0.0075 0.0121 0.0181 0.0251 40 1.049 0.0449 1.025 0.0429 40 1.380 0.0779 1.265 0.0653 40 1.610 0.106 1.505 0.0924 40 2.067 0.174 1.985 0.161 40 2.469 0.249 2.465 0.248 40 3.068 0.384 2.945 0.354 40 3.548 0.514 3.425 0-479 40 4.026 0.661 3.905 0.622 40 5.047 1.04 4.875 0.970 40 6.065 1.50 5.845 1.39 30 8.071 2.66 7.725 2.43 30 10.136 4.19 9.625 3.78 30 12.090 5.96 11.565 5.46 system may be determined from the following ASME for mula. This formula should be used only for operating tem peratures between 160 F and 280 F. (0.000411 - 0.0466) V, V,~ E. _ P. (4) Pf.'P* where ' V, *= minimum volume of theexpansion tank, gallons. V, =* system volume, gallons. t ~ maximum average operating temperature, Fahrenheit. Ps " pressure in the expansion tank when the water first enters, usually atmospheric pressure, feet of water, absolute. P/ ** initial fill or minimum pressure at tank, feet of water, absolute. . P maximum operating pressure at tank, feet of water, absolute. * 1. A widely used formula recommended for temperatures below 160 F is: . - Fig. 16.:.. Expansion of Water Above 40 F E net expansion of the water11 in the system when heated from minimum temperatures to maximum tempera ture, gallons (See Fig. 16). The volume of the water in a system should be determined from water capacities of heating units as given by manu facturers and the volume of pipe or tube from tables such as Table 5. Effect of Pump Location The required minimum pressure, Pi, and the maximum pressure in the expansion tank, P#, may change for spe Hot Water Heating Systems . 405 cific systems, depending on the effect of relative pump and tank location on system pressure changes caused by pump operation. Refer to diagrams A, B, C, and D of Fig. 17 and following discussion. The degree of system pressure change caused by pump operation is established by the pump bead. Whether the pump head will be added to, or subtracted from the system static pressure at the time of pump operation is determined by the relative pump and tank location. This is so because the junction of the tank with the system is a point of no pressure change regardless of whether or not the primp operates. Consequently, when the tank is located dose to the pump suction, the pump suction pressure is unchanged when the pump starts and the pump head appears as an increase of pressure on the system. Conversely, when the tank is located dose to the pump discharge, the pump discharge pressure is unchanged when the pump starts and the pump head appears as a decrease in pressure at the pump suction and on the system. . tank, but is commonly used in residential and other small installations where water volumes, system heights, and pump heads are all low. ' When the pump discharges into a boiler and the tank is connected to the pump suction line as in C, Fig. 17, the boiler is subjected to an increase in presure equal to the pump head when the pump operates. The required minimum pressure, Pr,.is as described for A, Fig. 17. The tank final operating pressure, P., equals the boiler working pressure, as discussed under A, Fig. 17, minus the pump head. With ar rangement C the size of the expansion tank will be smaller than for arrangement B, but larger than for arrangement A. Attic tanka are used for the purpose.of tank size reduc tion. When used, as shown in D, Fig. 17, a gage located at any point between the.tank and the discharge of the pump will show an increase in pressure when the pump operates, while any point between the tank and the suction line of the pump will show a decrease in pressure. This decrease in pressure on the suction side of the tank connection re quires that a pressure equal to friction loss between the tank connection and the suction of the pump should be added to the vertical distance the tank is located below the high point of the system to obtain the minimum tank pressure. Pi. Since the pump is located between the expansion tank con nection and the boiler, the maximum tank pressure, P*, would be obtained as described under C, Fig. 17, except that pump effect on the boiler pressure is reduced by the friction loss between the tank connection and the boiler. If the pump were discharging from the boiler instead of into it, the pump operation would not affect P.. ' The following Examples 5, and 6 illustrate the principles applying to rising of closed expansion tanks. Fig. 17.... Effect of Pump Location and Expansion Tank Connection ' When the pump discharges away from the boiler and expansion tank (A, Fig. 17) all pressure changes created by pump operation are additive. A gage located at any point in the system will show an increase in the pressure on starting the pump equal to the friction pressure drop between the gage and the boiler inlet (tank). Since the tank is. located on the boiler, boiler pressures are unaffected by pump operation. The minimum-pressure, Pt, required, is equal to height of the system above the expansion tank, plus any pressure required to assure positive air venting and prevent boiling; if the maximum water temperature exceeds 212 F. The maximum pressure, P, depends upon the pres sure rating of that item of equipment having the lowest rated working pressure, usually the boiler or boiler relief valve, and the vertical distance between it and the ex pansion tank. This arrangement is recommended where high head pumps are used. . When the pump discharges into the boiler and expansion tank (B, Fig. 17), all pressure changes induced by primp operation are subtractive. A gage, located at any point in the system, will show a decrease in pressure on starting the pump equal to the pipe friction pressure drop between the gage and boiler outlet (tank). Assuming no friction loss be tween the discharge of the pump and the expansion tank, the minimum pressure, Pt, must be increased above that discussed for A, Fig. 17, by the head of the pump. The maximum pressure, P., is determined as described for A, Fig. 17. Arrangement B results in the largest size expansion The system used in the examples has: (1) a water volume of 1000 gal, (2) a high point of the system at the top of a return riser 25 ft from the top of the boiler directly above the boiler room, (3) a circulating pump having a 20-ft head, and a 30 psi boiler with an ASME rated relief valve as the item of equipment having the lowest pressure rating. The Pm is atmospheric pres sure, 34 ft of water, absolute, in all examples. The design aver age water temperature is 200 F. Friction losses between the high point of the system and the boiler are assumed to be negligible. Example 4- Determine the size of expansion tank required when connected as shown in A, Fig. 17. . Solution: Installation is as shown in A, Fig. 17, with the ex pansion tank at the same level as the relief valve. The net ex pansion of the water in the system is represented by the term (0.00041 t -- 0.0466)7, of Equation 4 and, hence, is ' [(0.00041)(200) - 0.0466) (1000) = 35.4 gal. ' As stated, P is 34 ft of water, absolute. Referring to the dis cussion for A, Fig. 17, Pr, the minimum pressure, is equal to the height of the system above the expansion tank, 25 ft, plus 4 ft for positive venting, a total of 29 ft of water, gage, or 63 ft of wa ter, absolute. P, is equal to the relief valve setting, 30 psi X 231. ft of water, 693 ft of water, gage, or 1033 ft of water, absolute. . Substituting in Equation 4: 35.4 V, = 170 gal. 34 34 63 " 103.3 Example 5: Determine the size of expansion tank required when connected as shown in B, Fig. 17. . Solution: All conditions remain the same, except that the expansion tank connection is at the discharge of the pump rather than at the suction. When the pump operates, the pressure at the top of the return riser is reduced by an amount equal to the head of the pomp. Therefore, to maintain a positive pres sure at the top ofthe system, the minimum pressure must be in-. 406 CHAPTER 28 1959 Guide creased an amount equal to the bead of the pump, 20 ft of water. Ft, the minimum pressure, equals 29 plus 20, or 49 ft of water, gage, or 83 ft of water, absolute. The required volume by Equation 4 is 35.4 V, 34 34 440 gaL 83 " 103.3 Example 8: Determine the sire of expansion tank required when it is connected as shown in D, Fig. 17. Solution: The expansion tank is located at-the top of the system with the result that the height of the system has no effect on the required minimum pressure, P/. However, the tank is located far enough from the pump so that friction loss in the piping between the pump and the tank must be considered in determining the pressure effect of pump operation on system pressures. Ananmo that the **nk is located at a point such that the friction loss between the tank connection to the system and the suction of the pump is 8 ft, with the resistance in the return riser to the boiler still considered negligible. The pressure in the expansion tank remains the same whether the pump runs or not. Therefore, since 8 ft of friction loss exists between the expansion tank and the pump suction at the top of the return riser, the pressure in the expansion tank must be increased by that amount to maintain a positive air venting pressure at that point. - - P,, the minimum pressure in the tank should be the aim of 4 ft for positive venting pressure and 8 ft for pump effect, or 12 ft water, gage, which is 46 ft of water, absolute. Since the pump is located between the expansion tank connection and the boiler, P, the maximum premure tn the tank, must be less than the operating pressure of the relief valve by an amount equal to the effect of pump operation on the boiler pressure. In this case, the effect of the pump is reduced by the friction loss be tween the expansion tank and the boiler. The head of the pump, 20 ft, less friction as discused, 8 ft, is equal to 12 ft. ' P., then, is 69.3 less 12, which is 573 ft of water, gage, or 913 ft of water, absolute. Other factors remain as discussed in the other examples. Substituting in Equation 4 the required ex pansion tank is*. . 35.4 V, 34 34 96 gaL 46 91.3 In Example* 4, 6, and'6, the calculated size of the expansion tank has been indicated. It is customary practice to select a standard tank size not less than that calculated. The two following important factors in tank sizing have not been illustrated in the Examples 4 to 6: 1. Use of compressed air to increase the amount of'air in the tank. This factor affects the value of P* by increasing it above atmospheric pressure- The .use of compressed air to charge the expansion tank reduces the required tank volume. 2. Effect of a design maximum temperature higher than tit F. The effect of design temperatures above 212 as used by some de signers is given in the discussion of A, Fig. 17. It is posible to obtain proper operation of the expansion tank without adding the pressure required to maintain liquid water at temperatures in excess of 212 F. Two things are necessary on this basis of de sign: (a) the pressure increase in the system as the temperature increases from 40 F to 212 F and to the final design temperature must be sufficient to keep the pressure above that corresponding to the temperature of the water in order to prevent boiling and (6) the operating personnel for the system must be instructed regarding the proper pressure for various system temperatures in order that properpressure control of the system may be main tained. An automatic fill valve cannot be used to maintain the minimum pressure for such a system. In small systems where the volume of water is small and where the presures due to pump and static heads are low, expansion tanks are small and no critical problems are en countered. However, for large systems the ire of the ex pansion tank and the problems of pressure control can be come critical. The following means of reducing expansion tank size and establishing satisfactory pressure control may be investigated in addition to the methods discussed under A to D, Fig. 17: 1. Compressed air, if available, can be admitted to the expan sion tank to obtain the desired pressure. 2. The head of the pump may be reduced by the use of larger pipe Btfs, or greater design temperature drop. 3. The boiler may be constructed for pressures higher than 30 psig. 4. The steam boiler may be used with a steam-to-water heat. exchanger to heat the water circulated. ' ' The point of connection of the expansion tank to the system should be studied carefully to guard against the possibility of isolating the tank from a hot boiler or any part of the system by normal operation, of automatic, check, or fnaniiAl valves. . BOILER ROOM PIPING The arrangement of equipment, its capacity, and the piping arrangement for its connection will vary, depending upon the size and characteristics of the systems which it serves. Most of the principles involved in these arrangements have been discussed. Fig. 18 shows the piping and specialties considered necessary for the most basic system. The ASME Loro Pressure Heating Boiler Code requires that provision must be made for draining a closed expansion tank without emptying the system. A valve is commonly included in the expansion piping to the tank but it must not close a con nection to the safety relief valve. Fig. 19 shows a more elaborate multizone system. Most systems will fall between these extremes as the engineer fits the design to the require ments of the installation. - One device in boiler piping which facilitates elimination of air before it can enter the mains is the dip tube. Air will separate from the water in a heating system at a point where the velocity and pressure are the lowest and where the tem perature is the highest. Although the pressure at the boiler is generally high, it is a logical place to perform the separa tion.-Fig. 18 shows the use of a dip'tube. This extension of the outlet pipe forms a dead space at the highest and hottest part of the boiler. The air will tend to separate from the Rg. 18.... Basic Boiler Connections for a - Hot Water System Hot- Water Heating Systems 407 water in this space. Hie air can be conducted to the expan sion tank by a connection from the tank to the highest point of the boiler (see Fig. 18). The connecting pipe should be as direct as possible and be pitched upward continuously to the tank. If the expansion tank is not connected directly to the boiler, an automatic air vent valve should be installed at the high point of the boiler, instead. ' In general, the manufacturer's recommendation on the number of outlets to be used for a particular boiler for a given application should be followed.' This applies also to return connections. - The prevention of thermal shock through proper use of return connections should be considered in piping ar rangement. Where more than one pump are used for cir culation, the discharge of the pumps should be joined be fore being discharged into the boiler. A check valve should be installed in the discharge of each pump, unless another method of preventing backflow through the pump circuit is provided. Where temperatures higher than normal are maintained in the boiler, the connection of the return to the boiler should' follow the manufacturer's recommendations for such service. Where a multiple boiler installation is used, provisions should be made to prevent the bypassing of water through a boiler which is not being maintained at control tempera- - ture. In some cases this provision takes the form of auto matic control valves interlocked with the boiler temperature control to be open only when the temperature in the par ticular boiler is being maintained at operating conditions. In other cases, manual valves are installed in the boiler returns and opened only when the burner switch which places the firing device at the command of the boiler temperature control is in the ON position. ' Weighted check valves, or flow check valves, should be in stalled in the supply piping from the boiler to prevent grav ity circulation during periods when the circulating pumps are not operating. If the piping is arranged with separate sup plies to individual zones, a weighted check valve should be in stalled in the supply piping to each zone. THE USE OF STEAM WITH HOT WATER HEATING SYSTEMS The use of a steam boiler or district steam with a con verter (heat exchanger) has many advantages for tall build ings. The piping for the steam used in this type of a system should follow the principles outlined in Chapter 26, Steam Heating Systems. In tall buildings the system ran be zoned vertically as shown in Fig. 20, that is, with a given number of floors per zone and a converter for each zone. This type of design makes the limitation of maximum pressure in the system possible. With a converter-type system, the volume of water in the boiler is not a part of the volume of water causing thermal expansion in the system. Since the boiler in a hot water system may hold 30 to 50 percent of the total water volume of the system, the reduction in the of the expansion tank, and the problems involved therewith are of major importance. . The use of steam in extended-surface coils for heating air will often be more-desirable in a system where steam is available. This type of installation will result in less ex pensive coils, and simplified coil controls. TEMPERATURE CONTROL Methods of temperature control for hot water heating systems, including zone controls, are covered in Chapter 43, Automatic Control. - SYSTEM ADJUSTMENT Two common methods of determining the effects of ca pacity adjustment are: the measurement of space tempera- 408 CHAPTER 28 1959 Guide tures by room thermometers, and the determination of the temperature drop of water flowing through a heating unit or zone by means of surface contact thermometers or ther mometers instated in the piping. When adjustment is made by means of water temperature drop, the capacity of the units after adjustment must equal the heat delivery actually required. Control is then accomplished by making the tem perature drop through all units equal. (Previtfon AoM be mad* far expansion in *aA doted aTcurf) fig. 20.... Vertical Zoning of Hot Water Heating System m a 12-Story Building The procedure for matting a permanent adjustment of heat . distribution in a larger system should be as follows: 1. Select a time or day when conditions of heat gain are minimum; ie., nighttime or an overcast day. Outdoor tempera tures should be such as to require at least SO percent of the sys tem capacity to maintain the design indoor temperature. 2. Place the system in operation and make certain that all valves, adjusting fittings, and dampers are in the open position. Automatic oontrol which might reduce the flow or capacity of any unit should be rendered inoperative. Doors and openings between rooms should be closed. 3. Prepare a form for recording data on temperatures in spaces or at the supply and return of heating elements or of cones. . 4. After the. system has reached equilibrium a complete rec ord should be made of temperatures throughout the system. 5. An initial adjustment of flow regulating devices in the sys tem should be made on the basis of the record of the original readings. A new set of temperature readings should be recorded after sufficient time has been allowed to establish a new equilib rium throughout the building. .. 6. Continue adjustments of flow control devices until a satis factory condition is obtained. 7. When a satisfactory adjustment has been accomplished, it is advisable to mark ike position of each of the adjusting fit tings or valves. This facilitates return to proper control settings if the flow controls are disturbed by accidental or emergency changes at any time. ' CARE AND MAINTENANCE OF SYSTEMS A hot water heating system should last during the life of the building if it is designed, installed, and maintained properly. Maintenance instructions for individual elements of the system such as burners, motors, pumps, and accessories . may be obtained from the manufacturers who supply this equipment. Two factors contribute in a most important way to the satisfactory operation and life of the hot water heat ing system: (1) the proper cleaning of the system when in stalled; and (2) a minimum change of water in the system, except as required by periodic maintenance of the boiler or draining of the expansion tank. INITIAL CLEANING OF SYSTEM . Rules that should be followed for the initial cleaning of the system are: 1. All equipment and piping should be thoroughly cleaned of iron cuttings and other refuse during assembly and installation. 2. When installation is complete, the system should be filled with a solution of 1 lb of trisodium phosphate per 50 gal of water and should be operated for 24 hr at maximum tempera ture with all pumps operating. The system should then be drained and thoroughly flushed with water before refilling. In order to minimise the addition of water to the heating- system, the operation of air-vent valves, relief valves, and the tightness of the system generally should be subject to continuous inspection. Drip6 from automatic air-vent valves should discharge in places where leakage is readily detected. Continual operation of the pressure relief valve should be a gijrnal for the inspection, repair, or replacement of the relief valve, or a check on the operation of the expansion tank or the automatic water feeder, if one is provided. REFERENCES 1J. H. Keenan and F. G. Keyes: Thermodynamic Properties of Steam (John Wiley it Sons, New York, 1936, 1st ed.). . * F. E. Giesecke and J. S. Hopper: Friction heads in standard six-inch pipe (ASHVE Transactions, Voi. 47, 1941, p. 71). *F. E. Giesecke and J. S. Hopper: Comparative study of friction heads in screwed and welded elbows (ASHVE Trans actions, Vol. 48, 1942, p. 201). 4 F. E. Giesecke: Friction heads due to water flow in copper, brass, and other smooth pipes (ASHVE Transactions, Vol. 49, 1943, p. 175). *F. E. Giesecke: Determination of pipe sizes for hot water heating systems (ASHVE Transactions, Vol. 21, 1915, p. 473). * F. E. Giesecke: Friction of water in iron pipes and elbows (ASHVE Transactions, Vol. 23,1917, p. 499). TF. E. Giesecke: Effect of temperature upon the friction of water in pipes (ASHVE Transactions, Vol. 31, 1925, p. 9). F. E. Giesecke: Friction of Water in elbows (ASHVE Transactions, Vol. 32, 1926, p. 303). ' '*F.. E. Giesecke and W. H. Badgett: Friction heads in oneinch standard cast-iron tees (ASHVE Transactions, Vol. 37, 1931, p. 395). "F. E. Giesecke and W. H. Badgett: Loss of head in copper pipe and fittings (ASHVE Transactions, Vol. 38, 1932, p. 529). UF. E. Giesecke and W. H. Badgett: Supplementary friction heads in one-inch cast-iron tees (ASHVE Transactions, Vol. 38, 1932, p. 111). u F. E. Giesecke: Two methods of figuring the friction loss in pipe lines (ASHVE Transactions, Vol. 59, 1953, p- 49). "L. N. Montgomery and W. 8. Harris: Sources of vent gas in a hot water beating system (ASHAE Transactions, Vol. 61, 1955, p. 483). 14 Low-pressure heating boilers' (ASMS Boiler and Pressure Vessel Code, with 1954 and 1955 addenda, Section IV). " R. C. Chewning and R. W. Peterson: Consider pump heads when sizing hot water expansion tAnin (Heating, Piping and Air Conditioning, July 1955, p. 106). . u H. A. Lockhart and G. F. Carlson: Compression tank selec tion for hot water heating systems (ASHVE Transactions, Vol. 59, 1953, p. 55). "Oscar Faber and J. R. Kell: Heating and Air Conditioning of Buildings (Architectural Press, London). CHAPTER 29 HIGH-TEMPERATURE WATER SYSTEMS Features; Basic System; Design Considerations: Boilers, Boiler Piping and Controls, Direct-Contact Heaters and Auxiliary Heat Exchangers, Boiler Feed Pumps, Circulating Pumps; Distribution Piping Design: `District Distribution, Pipe, Valves and Fittings, Thermometers and Pressure Gages; Space Heating Equipment; Temperature Control; Water Treat ment; Storage HIGH-TEMPERATURE water systems discussed in The size of installation, the extent of the load, and the this chapter are those operating with supply water at operating temperature will govern central boiler-plant de temperatures exceeding 250 F. Operating temperatures rangseign and construction. Some determining considerations are: from 250 to 430 F, with pressures from 55 to 350 psig. Hightemperature water systems used in the United States are predominantly closed-type systems. This chapter is intended to give a broad general idea of 1. Type of load: heating, process, or both. 2. Distance from heating plant to space or process requiring heat. 3. Terrain of land on which buildings are located. . principles and practices that apply to high-temperature systems and distinguish these systems from the systems oit erating below 250 F. . . 4. Zoning requirements based on occupancy and load dis tribution. 5. Quantity of steam used for power equipment, if required. FEATURES OF SYSTEMS The following ore among the outstanding features of high temperature as compared to low temperature systems: 1.It is common practice to use greater temperature drops. 2. Supply and return piping may be given the same pitch or grade, or may be run level. Grading is desirable but a definite minimum pitch is not required. . ' 3. Piping may slope up or down or run at a variety of ele vations to suit the terrain and the architectural and structural requirements without provision for drainage at each low point except for emptying sections of piping for shutdown. This fea ture may reduce the excavations required. 4. The pressure in any part of the system must alwayB be above the pressure corresponding to the temperature at satura tion in the system in order to prevent flashing of the water into steam. 5. Processes requiring different temperatures of water may be served at their required temperatures by use of heat ex changers, by regulating the flow to certain processes, by plac ing some processes in series with others, etc. 6. Heat may be stored in the mains and boiler by build-up of temperature in the return main during periods of light load. THE BASIC SYSTEM High-temperature water systems are basically similar to the conventional forced hot water heating systems since they require boilers or direct contact heaters for heating the wa ter, expansion or pressurizing tanks or both, circulating pumps, distribution piping, and heat transfer or emission equipment, as shown in Fig. 1. The principal differences from the low temperature system are the higher pressure used, the consequently heavier equipment, and the manner in which pressure is maintained on the water. When cush ioned by steam in the boiler, the system in effect is a hot water system using a boiler, producing stedm to beat the water. The supply piping draws water from the boiler below its water level so'that water'flow may occur even though steam is kept above the surface of the water. For an equiva lent heat load the rate of water flow through the boiler is 6 to 10 times that for steam systems. Water is circulated in a closed circuit from the central sta tion to areas where heat is required and back to the boiler. Variations in elevation may make it desirable to locate the boiler house on the highest ground in order to obtain maxi mum static presure bead on the system. Boiler auxiliaries such as boiler feed pumps, pressure tanks, economizers, and system circulating pumps are usually located in the boiler house, as indicated in Fig. 2. DESIGN CONSIDERATIONS Factors to be considered in selecting the type of boiler are (1) the maximum operating pressure of the system, (2) the water temperature requirements during a 24-hr operat ing period, and (3) the size of the load. Process loads may require water at a given minimum supply temperature con tinuously, while space heating and other loads may permit a lower water temperature at night or an off period during each 24-hr operating period. . Water temperature requirements also influence the man ner of pressurizing the system. Simplicity of operation is an important consideration in selecting a method of pressuriz ing when boilers are not operated during the night. Varia tions in supply water temperature and temperature drop also should be taken into account in selecting a pressurizing method. Theoretically, water temperatures up to about 350 F may be provided using boilers and piping suitable for 125 psig, but practically, maximum water temperatures will be limited 410 CHAPTER 29 1959 Guide TEMPERATURE -F fig. 3.... Relation of Saturation Pressure and Enthalpy to Water Temperature by the system design and elevation characteristics to values between 300 F to 325 F. Most systems are being designed with the system circulating pump in the supply line and with a steam drum for pressurization, expansion, and tem perature control. In this type of system, the temperature of the water from the steam drum cannot exceed the tern- Table 1 ....Properties of Water (212 F to 400 F) Teaipefvtw* F Oeasfy Ib/OiFt Speatic Kmt 6h/(U>HF) Tofo/ Hatit Abo** 32 F Bta/Lfa* Bhi/Cu Ft 212 220 230 240 250 260 270 280 290 300 310 320 330 340 350 360 370 380 390 400 14.70 17.19 20.78 24.97 29.83 35.43 41.86 49.20 57.56 67.01 77.68 89.66 103.06 118.01 134.63 153.04 173.37 195.77 220.37 247.31 59.81 59.63 59.38 59.10 58.82 58.51 58.24 -57.94 57.64 57.31 56.98 56.66 56.31 55.96 55.59 55.22 54.85 54.47 54.05 53.65 1.007 1.009 1.010 1.012 1.015 1.017 1.020 1.022 1.025 1.032 1.035 ,1.040 1.042 1.047 1.052 - 1.057 1.062 1.070 1.077 1.085 180.07 188.13 198.23 208.34 218.48 10,770 11,216 11,770 12,313 12,851 228.64 238.84 249.06 259.31 269.59 13,378 13,910 14,430 14,947 15,450 279.92 290.28 300.68 311.13 321.63 15,950 16,437 16,931 17,409 17,879 332.18 342.79 353.45 364.17 374.97 18,343 18,802 19,252 19,681 20,117 ' * Reprinted by permunion from rtnuodfuamtc PreptrtUa ofShorn, by J. H. KwMab mad P. G. Key** pubiizbed by John Wiley *ad Son*. Inc.. ISM oditioo. perature of the steam in the drum which corresponds to its pressure at saturation. The point of maximum pressure is at the discharge of the circulating pump. If this pressure is to be maintained below 125 prig, the pressure in the drum, corresponding to the water temperature, cannot exceed 125 psig minus the sum of the pump head and the pressure head due to the difference in elevation between the drum and the circulating pump. ' Elevation effects and the' pressures required to prevent the flashing of water to steam in the supply system can also High-Temperature Water Systems 411 limit the maximum water temperature that may be used and must, therefore, be studied in evaluating the tempera ture-pressure relationships of the system. The properties of water which govern the features of the design are: . 1. Temperature vs pressure at saturation (see Fig. 3). 2. Density or specific volume (t>) vs temperature. .3. Enthalpy or sensible heat (ht) vs temperature. 4. Viscosity vs temperature. The relation of temperature and pressure, specific vol ume, and enthalpy are all discussed in Chapter.3. Data for the normal temperature-pressure ranges are given in Table 3 of Chapter 3. The properties of water for the range 212 F to 400 F are shown in Table 1. Water temperatures of 350 to 400 F requiring 250 psig working pressure will largely be limited to district and in stitutional installations. In such applications the heat quan tities and distances to be covered usually justify the added cost of the heavier pipe, fittings and special valves. Boilers The boiler plants of the larger high-temperature water systems are comparable to boiler plants of power generating stations operating within the same pressure range. The boil ers should be selected for size and type in keeping with the load and design pressures. Both steam for power or process ing and high-temperature water for heating may be supplied from the same boiler plant. The load is determined by the heat required for: 1. Space heating and winter air conditioning. 2. Generated steam required for power. 3. Water heating or heat processes. The boilers may be water-tube, horizontal return-tube or Scotch marine type, and may be equipped with any conven tional fuel-firing apparatus. Water-tube boilers are favored for higher pressure' ranges--200 psig and upward. Boilers may be of either forced circulation or gravity circulation type. The circulating pump of forced circulation boilers must operate continuously during operation of the boiler. Water- tube boilers frequently require separate vessels for the pressure cushions, depending on the volume of the steam drum relative to system requirements. When systems using fire-tube boilers are cushioned by steam, expansion space may be available within the boiler itself.1 A separate vessel usually is used when the' system is cushioned by air or other gas. " Proper distribution, of return water and of water flow is essential in all types of boilers to prevent tube failures due to overheating or unequal expansion in boiler tubes. Expansion Pressure Cushion Four methods are used to produce and maintain the neces sary pressures on the system: . ' 1. A steam cushion in. the attain space of the boiler or a steam drum. 2. A separate expansion tank for steam .pressurizing. 3. Compression tank with comprised air or an inert gas. * 4. An automatic pressure pump.*- * * A steam cushion or a pneumatic cushion is generally fa vored because it may also accommodate the expansion. The steam cushion method for maintaining pressure above the water level in the boiler requires space to accommodate the expansion of the water volume within the system when heated to the system operating temperature. Systems which do not use steam for maintaining the required pressure, or in which the boiler steam space is inadequate to accommodate the change in water volume, will require additional tanka or steam drums for expansion. The arrangement of the tanks for pneumatic cushioning is similar to the closed expansion tanka when air pressures are used for cushioning or pressurizing. A suitable means of balancing or a connection from the bottom of the tank should be made to the main system return header. (See Fig. 4.) . - A major problem when pressurizing by steam is to main tain a proper boiler water level while providing for the change in water volume due to expansion and contraction. Boiler water level and flow connections should be designed to utilize the steam drum in adjusting to changes in water fig. A .... Schematic Arrangement of Combustion and Feed-Water Controls 412 CHAPTER 29 1959 Guide Ctrcvfating Pump m Return Main RETURN --" may also be done by a continuously Gpetatmg boiler feed pump. ' Boiler Piping When the circulation pumps discharge to the system sup ply piping, the flow main should not rise above'the boiler water Hnw high mmigh to reduce the total pressure suffi ciently to permit flashing in the piping. Whether the pump is connected so as to deliver water to the system supply piping or to the boiler inlet line, the arrangement is a com plete circuit and the water is returned to the boiler for re heating. The returned water is brought into the boiler be low the water line as shown in Fig. 5* When two or more boilers are used to supply a common load, means must be provided to equalize the flow of water to each boiler (see Fig. 6). Automatic water control is de sirable. Balance pipes to maintain equal pressures must be liberal in size as shown in the following table. Softer Rating MASofts fitirfi 2.5 5 10 15 20 30 .. Bafance Pipe Dm, laches 3 3M 4 5 6 .8 fig. 5.... Arrangement of Boiler Piping volume. The problem of change in water expansion and contraction is minimised by rarely closing down a large system after it is in operation. * When pressurizing with a boiler feed pump automatically operated by pressure control, a relief valve for the maximum system pressure is provided. The pressure control is set to operate the boiler feed pump and feed water from the make-up tank to the boiler whenever the pressure falls to the regulator cut-in point setting, and stop when the cut-out point is reached. If the pressure increases beyond the 6afe limit of relief valve setting, excess water will flow through the relief valve to the make-up water tank. Pressurizing - Valves should be used in connections to individual boilers when more than one boiler is required as in power plant practice. .. Natural or forced circulation may be used to produce in ternal boiler flow. Internal baffles or distribution pipes are arranged to prevent stratification and promote circulation in the boilers.-Arrangements for this purpose vary with the High-Temperature Water Systems various designs. In natural circulation, convection currents and the system circulating pump circulate the water through the boiler. Fig. 7 shows the piping arrangement for the sys tem which is also known as the combined pump system. This method should be used only with boilers having a com paratively low. pumping head loss.1 In forced circulation boilers a circulating pump takes the water from the steam drum and discharges it back into the boiler, the proper water path being obtained by suitable boiler design. This is referred to as the separate pump sys tem because the boiler circulating pump is separate from the distribution'system pumps. One pump is normally used for each boiler to draw water from the expansion drum, circulate it through the boiler and return it to the expansion drum (Fig. 8). The system circulating pumps draw water from the expansion drum and circulate it through the dis tribution system only. The system return is connected to the suction side of boiler circulating pumps or to the expansion drum. This method permits the use of boilers with either high or low head loss. With steam pressurizing, the water line must be held within proper limits to always provide a water seal at the entrance to the supply flow pipe. Otherwise, flashing or steam bubbling could occur in the supply pipe as the water level rises and falls. Boiler Controls ' Some of the automatic controls indicated in Fig. 4 and ex tensively used for operating boiler plants are: 1. Automatic combustion and.safety control: control of fuel and combustion with flow changes. * 2. Water level control: control of make-up and-ehutdown on low water. 3. Safety valve (steam), automatic relief valve (hot water): 4T3 fig. 9....Direct Contact Heater for Generating High - Temperature Water on large water systems small additional relief valves should be provided to relieve minor excess pressures. On installations large enough for high-temperature water heating to be economic, automatic control is usually a worth while investment. When package type boilers are used, auto matic combustion control and water level control are usu ally components of the boiler package. Direct-Contact Heaters and Auxiliary Heat Ex changers High-temperature water may be obtained from directcontact heaters in which steam from turbine exhaust, ex tractors, or steam boilers is mixed with return water from the system (see Fig. 9). The mixture takes place in the upper part of the heater where the water r-asnading from horizontal baffles comes in direct contact with steam. The steam in the upper part of the heater serves as the steam cushion for pressurizing the system. The lower' part of the heater serves as the-expansion tank for the system. Where the water heater and the boiler operate under the same pressure, the surplus water is usually returned to the boiler through a pipeline connecting the outlet of the hightemperature water circulating pump to the boiler. This fig. 6.... Piping Connections for Two or More Boilers in High-Temperature Water Systems Pressurized by Steam 'fig. 7.... High-Temperature Water Piping for Combined . Pump System fig. 10....High-Temperature Heat Exchanger Heating Water for Low-Temperature Heating System 414 CHAPTER 29 1959 Guide system is also applicable where mixed steam and high-tem perature water services are required.* Fig. 10 shows a method by which high-temperature water in a heat exchanger heats water for a comfort heating sys tem which uses supply water temperatures of 180 F to 240 F. With high-temperature water at 300 to 350 F a temperature differential between entering and leaving water of approxi mately 100 deg may be used- Automatic control of such generators or converters is preferable and is discussed in a later section. Temperature Control. Fig. 11 shows a tubular heat exchanger in which low- or medium-presure steam is produced by heat transferred from high-temperature water circulated through the tubes. In order to produce the required quantity of steam the mean water temperature in the tubes may need to be within 20 to 30 deg of die original temperature of water in the high temperature system. Boiler Feed Pumps Boiler feed pump6 should be provided for supplying make-up water to the boilers where local pressures are, or may be, below the boiler pressure. If the boiler plant sup plies steam for heating only, the pump sizes will be small. Boiler feed pumps should, however, have reserve capacity and should have a hot well or receiver whose water level is controlled by automatic means. When steam is used for power purposes, boiler feed pumps must not only return condensate' but also supply make-up water to replace wasted condensate. Grculating Pumps Circulating pumps for temperatures above 240 F should be built for continuous operation at high temperature. The preferable types have bearings and stuffing boxes that are water cooled. The bed plate and mountings should be de signed to permit expansion and contraction without causing misalignment. Since continuity of service depends upon the circulating pumps, they should be installed in duplicate to provide standby service. It is good practice to locate the circulating pump in the supply line in order to maintain all parts of the distributing system at pressures exceeding boiler pressure. This location is also preferred since water in the system would into steam if the pressure in the piping decreased below the pressure corresponding to the temperature of the water at saturation. .Connections which permit some return water to bypass the boiler and enter the supply line as a means of preventing flash steam in the flow main are very important. Sufficient net positive suction head (NPSH) should be available at the pump suction flange. Proper design of the pump piping in this respect will avoid cavitation* In select ing a pump its pumping head and water circulation rate must be carefully evaluated in order to permit selection of the proper driving motor. The effect of density variation between the high and low temperature must be considered. Pump characteristics as affected by system characteristics, should be given consideration to insure nonoverloading conditions in pump motor operation. ' DISTRIBUTION PIPING DESIGN The arrangement of piping and necessity for zoning will be determined by such factors as the hours of operation, the nature of the space occupancy, and the required water temperature. These factors, together with the heat require ments of the equipment served, will establish the tempera ture drop which, in common practice, may range from 80 to 150 deg. Economic considerations require that the savings due to use of small pipe and high velocity circulation be balanced against the cost of valves, pumps, etc., that are suitable for operation at the high friction loss and pressure. The best overall investment will be secured when there is a proper relation between first cost, operating cost (including that of the operating personnel), and the fixed charges. . Fig. 12 shows the relation (based on the Fanning formula in Equation 8 of Chapter 4) of the water flow in thousands of pounds per hour to the friction loss in feet of 62 F water at a mean temperature of 300 F in Schedule 40 commercial steel pipe in sizes Vi to 12 in. The temperature 300 F is a normal mean between flow and return temperatures in the system. Correction of friction loss for other temperatures may be obtained from Fig. 13. Allowance for friction loss in fittings may be obtained from Table 2. District Distribution . The conventional conduit or tunnel distribution systems are employed with similar techniques used for installation. Although the mains may be run at different elevations at will, it is important that high points be vented and the low points drained by the air collection and venting arrangement described earlier. Grading is not critical. See Chapter 27, District Heating. The piping serving each building or process load should have a valved bypass connection between the supply and the return pipe in addition to the usual stop valves as indi cated in Fig. 1. -' Pipe, Valves, and Fittings All pipe, valves, and fittings used in high-temperature systems Bhould comply with the requirements of the Ameri can Standard Code for Pressure Piping, ASA B 31.1--1955. This code states that hot water systems shall be designed for the highest pressure and temperature actually existing in the piping under normal operation. This pressure is the cushion pressure plus pump head plus static pressure. Individual heating equipment units should preferably be installed with a lock-shield valve for balancing the flow and a separate valve for shut-off. These may be placed in the most convenient position for accessibility. If the unit is to be isolated for service, valves will be needed in both the supply and return piping to the unit. Valve trim should be of stainless steel or other alloy that will prevent corrosion. High-Temperature Water Systems 4,1$ (Friction giroa to fee* of 62 F trofee per 100 ft of pipe.) Fig. 12.... Friction Loss for 300 F Water in Commercial Steel Pipe (Schedule 40) Thermostatically operated valves in the control equipment should be of the electric-motor-operated or pneumatic type. Their selection is discussed in' a later section, Temperature Control. (See also Chapter 43, Automatic Control.) High points in piping should be provided with chambers and air vents for collecting and removing air and low points should have provision for sludge removal, as illustrated in Fig. 14. Loop-type expansion joints, in which the expansion is ab sorbed by deflection of the pipe loop, are preferable to the packed-metal type. If rmyhitnira) expansion joints are used, they should be of the guided type. As high-temperature water is more penetrating than low- temperature water, leakage due partly to capillary action should not be ignored because even a small amount of leak age vaporizes immediately. This slight leakage becomes no ticeable only on the outride of the gland and stem of the valve where thin deposits of salt are left after evaporation. The insulation of high-temperature water lines is similar to that of steam lines.* The selection of the economical thick ness of pipe insulation is discussed-in Chapter 32. JteprinM by p*reunion frets ftsferencs 9. Fig. 13.... Correction of 300 F Friction Loss for Other Water Temperatures i j | * i 1 1 ij {i ,. ; i f | ' , j . ? 416 CHAPTER 29 1959 Guide Thermometers end Pressure Gags? . Pressure gages should be installed in the pump discharge and suction and at locations where pressure readings will assist operation and maintenance. Thermometers (prefer ably dial type) or thermometer wells should be installed in the flow and return pipes, the pump suction and discharge, and at any other points of major temperature change or where temperatures are of importance in operating the sys tem. Thermometers and gages are desirable in the piping at the entrance to each building, hot water converter, or steam converter. (See Chapter 44.) SPACE HEATING EQUIPMENT In industrial areas, space heating equipment may often be operated with high-temperature water due to its avail ability. Convectors and radiators may require water tem peratures in the low and medium temperature range (13) to 180 F or 200 to 250 F) depending upon how close they are to the occupants and upon the pressure for which am designed.'The water velocity through the heating equipment affects its capacity. This must be taken into account in se lecting the equipment because, if a large water-temperature drop is used, the rate of circulation is reduced and conse quently the velocity of flow may be reduced sufficiently to lower, appreciably the rate of heat transfer. (See Chapter 5.) TEMPERATURE CONTROL . The principles'discussed under Control of Flow in Chapter 43 apply to high-temperature water systems, but added con sideration should be given to the selection and location of control components. Valve Selection Valve selection and sizing are very important because of the relatively high temperature drops and smaller flows en countered in high-temperature water systems. To obtain Table 2....Head Loss In Fittings (for tobohnf Aev] PBfiegt Pip* Sm Indie* Ftet of Soian Sir* Pipe Haring EqvcHoa* 10 8 6 5 4 3 ' 2 IK IK 1 HM Globe Valve............... ................................... Gate Valve.................................................... 90* Welding Elbow...................................... 45* Welding Elbow...................................... 340 270 200 170 135 105 83 7 5.75 4.5 3.5 3 2.2 1.7 11 8.5 6.5 5.5 4.5 3.5 2.6 76 4.5 3.6 3 2.4 1.7 70 1.5 2.2 1.5 55 1.2 1.8 1.2 45 1 1.5 1 36 0.8 1.2 0.8 28 0.6 0.9 0.6 21 0.5 0.7 0.5 22K* Welding Elbow.............................. . Literal"......................................................... Lateral*......................................................... Welding Tee................................................ 54 26 20 17 14 13 10 3 2.5 2 1.6 1.3 1.1 0.9 0.7 0.6 0.5 0.3 16 13 11 8 6.5 5.5 4 3.5 2.8 2.2 1.6 10 8.5 7 5 4 3.5 2.8 2.5 1.8 1.5 1.1 8 7 6.6 4 3.2 2.6 2 1.7 1.4 1.2 0.8 Concentric front. N. . 10 . .6 6 5 A 3 m 2 H IM 1 H H " . 10 8 ft. 5 4 3 2H 2* .m i K a 1 2.5 3 2.8 _ 3.5 \ 1.2 2 2.2 2.2 - c ONT RAC TIN 10 3.5 0.5 1.3 1.8 1.7 12 7.5 1.5 0.5 1.2 1.4 1.5 12 9.6 4.5 1.5 \ 0.6 1.2 1.4 1.5 10 7 5 1.8 \ 0 0.8 1 1 7.5 6 3.8 0.7 0 0.7 0.8 0.75 6 5 2.5 0.8 0 0.6 0.6 0.6 5 3.8 2.8 9 0 0.5 0.5 0.5 E 'ILAIIGIN a,. 4 3 2 0.3 0 3 2.5 1.25 0.5 0 0.3 0 0.3 2.5 2 1.3 0.5 0 2 1.8 1.5 0.8 * Compiled from dote published by Tub* TVrat, loo, * Division ot tbs Notional Cylinder Qas Co. Uaed by permission. b Water deflected throucb branch. ' Water flowing itnigbt throogh fit ting. 4 For eccentric redtun*, the valnea read for concentric reducer* matt be increased by * Banivalcnt length of pipe having a Fanning (rictus coefficient at OJXM. High-Temperature Water Systems 417 rood control, the valve must be sized so that it is effective over its full range of stem travel. It is recommended that the valve be selected on the basis of a pressure drop at full flow equal to approximately 50 percent of the pressure dif . ference between supply and return mains at the location of the equipment served. The pressure drop across the valve must not be sufficient to-result in a downstream pressure below the saturation pressure at the temperature existing at any point or flushing into steam will result. A valve with equal percentage flow characteristics is desirable. Sometimes two all valves are used rather than one large valve to improve the controllability of the system. Stainless steel trim is recommended, and all valve body materials and packing should be suitable for the high temperatures and pressures encountered. -The valve should have a close-off rating at least equal to the mmimnm head produced by the circu lating pump. Generally, two-way valves are more desirable tfhnn the three-way type because of the equal percentage flow characteristics and the smaller capacities available in two-way valves. Single-seated valves are recommended in Fig. 14....Methods of Venting High-Temperature Water . Mains preference to double-seated valves since the latter do not provide tight dosing. Valve Location Control valves preferably should be located in the return linfta from heat transfer units in order to reduce the valve operating temperature and to prevent the high-temperature water from flashing to steam at the lower discharge pressure. Sometimes valves are located 8s low as practicable to in crease the static head at the valve and further minimize the possibility of flashing. ` Typical Applications A typical application is the control of the temperature of water leaving a heat exchanger in which high-temperature water is used as the heating medium. The temperature measuring element should be located where it can best detect - changes and thus prevent overheating of the outlet water and possible flashing. When the measuring dement is lo cated in the leaving water, there must be a continuous flow through the exchanger and past the dement. If the water leaving the exchanger is used for space heating, the set point of the thermostat in this water (which controls the temperature of the leaving water by controlling the inlet temperature to the exchanger) can be readjusted in accord ance with outdoor temperature. Another typical application is the control of a low- or medium-pressure steam generator, usually less than 50 psdg, using high-temperature water as the source of heat. In this application a proportional pressure controller in the steam generator supply positions a high-temperature water valve located in the return line to maintain the desired steam pres sure. - High-temperature water is' sometimes used to supply coils in dr handling units where hpAting surfaces are so placed that possibility of personal contact is avoided. Care ful sizing of coil and valve is required to obtain stable con trol. In some cases face and bypass damper control is used, 418 CHAPTER 29 1959 Guide because then the control of water Sow through the coil is not as critical. . In some face and bypass damper control is used in conjunction with valve control. The coil valve, operating in sequence with the damper, must be closed when the face damper is closed. The coil arrangement should be such as to minimize air temperature pick-up when the bypass damper is at or near the open position. WAT TREATMENT Water treatment is seldom required where there is con tinual re-use of the water. Where none of the water is lost, except such minor amounts as may accompany venting or be due to occasional leakage at stuffing boxes, it is usually suffi cient to make the water slightly alkaline when the system is first filled. Where the make-up water is appreciable, treat ment appropriate to the mineral content and quantity is indicated. See Closed Recirculation Systems in Chapter 55. It is desirable that systems'with steam driven auxiliaries be arranged to conserve the heat in the exhaust. Steam driven auxiliaries can rarely be justified unless the exhaust steam can be used.' Usually this is accomplished with a minor ad dition in capital expenditure. Fig. 15 shows an arrangement for boiler feed where exhaust steam is available. STORAGE High-temperature water systems may be operated to even out the peak loads and low loads within 24-hr cycles by storage. Storage is usually accomplished by the bypassing of water from the flow to the return mains and thereby storing heat in the return main for future use, or storing heat in accumulators. Systems which .experience normal peaks may obtain as much as 15 percent added capacity through such heat storage. - REFERENCES lJ. G. Frost: High temperature hot water boiler plant at Dartmouth (The Engineering Journal of Canada, June 1953). ' O. S. Lieberg: High temperature water (dir Conditioning, Heating and Ventilating, September 1955, p. 83; November 1955, p. 85; January 1956, p. 69). Also published as a separate bulletin. *E. A. Pierce: High pressure hot water systems (The Heat ing and Ventilating Engineer <4 Journal of Air Conditioning, London, 1942). J. R. Kell: High presure hot water (Beating, Piping and Air Conditioning, April 1948, p. 93; June 1948, p. 97; August 1948, p. 91; October 1948, p. 85). 'George Applegate, Jr.: British and European design and construction methods (ASHAE Joubnal Section, Heating, Pip ing and Air Conditioning, March 1958, p. 169). 'C. A. Carter and B. L. Sturtevant: Design of high tem perature water systems for military installations (ASHAE Joubnal Section, Heating, Piping and Air Conditioning, Febru ary 1958, p. 109). (E. G. Hansen and William Liddy: A flexible high pressure hot water and steam boiler plant (Power, May 1958, p. 109). * Centrifugal Pump Section, Standard* of the Hydraulic Institute, p. B(Vi)-9 (Hydraulic Institute, New York, 1955). 'Oscar Faber and J. R. Kell: Heatina and Air Conditioning of Buildings (Architectural Press, London). BIBLIOGRAPHY J. H. Keenan and F. G. Keyes: Thermodynamic Properties of Steam (John Wiley & Sons, Inc, New York, 1936, 1st ed.). 5. R. Lewis: Hot-water system of advantage in meeting plant heating requirements (Heating, Piping ana Air Conditioning, May 1938, p. 319). K. Aschof: Die Calliqua-Heisswasserheizung (Die Warmer Zeitschrift fur Dampfkessel Ac Machinenbetrieb, October 1931). F. R. L. White: Some notes on high-pressure hot-water heat ing (Journal of the Institution of Heating and Ventilating En gineers, 1945). P. L.. Geiringer: High pressure hot water (Heating, Piping and Air Conditioning, May 1948, p. 103). T. W. Reynolds: The high temperature water system (Heat ing and Ventilating, September 1951). High Temperature High Pressure Hot Water Heating Man ual No. 2685 (Dunham-Bush, Inc., New York, 1955). Charles Broder: Heating and air-conditioning a civilian air port (ASHAE Joubnal Section, Heating, Piping and Air Con ditioning, March 1958, p. 147). - 6. W. Brown: Marine applications of high-temperature wa ter (ASHAE Joubnal Section, Heating, Piping and Air Con ditioning, March 1958, p. 161). E. M. Thompson: Economic evaluation of high-tempera ture water (ASHAE Joubnal Section, Heating, Pipmg and Air Conditioning, April 1958, p. 140). CHAPTER 30 PANEL HEATING Application Methods: Embedded Piping for Ceilings, Waifs, or Floors; Warm Air and Electricatfy Heated Ceilings, Waffs, or Floors; Output from Panel Surfaces: Radiation, Convection and Combined Heat Transfer, Panel Heat Losses; Design of Panel Hearing Systems: Warm Water Ponds for Plaster, Metal, and Concrete Ceilings; Wall Panels and Concrete Floor Panels, Installation Details and Accessories, Controls,- Warm Air and Electric Panels N this chapter the term. Panel Heating, is used to describe I a method of space heating in which heat is supplied by large heated areas of interior room surfaces operating at relatively low surface temperatures (80 to 125 F). The heating elements usually consist of warm water piping, warm air ducts, or low temperature electrical resistance elements embedded in, or located behind, ceiling, wall, or floor sur faces. Panel heating may be considered as another method of convenient and effective space heating. The heat loss require ments may be calculated in the conventional manner except that the heat loss through the area occupied by the heated panel need not be included. An assumed or computed reverse heat loss from the panel, however, should be* included in determining heating main size and the boiler load. The heat release from the panel is expressed in terms of hourly heat output per square foot of surface. The room air temperatures to be maintained are approximately the same as those maintained by heating systems employing cast-iron radiators, convectors, or warm air ducts. This chapter does not include a separate discussion of such topics as the influence of radiation on human comfort, the mechanisms by which human beings release heat, and other simitar topics- that apply to all methods of twating interior spaces for.human comfort. The reader is referred to Chapter 6 for a detailed discussion of these subjects. antimony, or capillary brazing alloys, be used. All piping should be subjected to a hydrostatic test of at least three timw the working pressure, but not less than 150 psig. The most common forms of panels applied in panel heating arc: (1) embedded piping for ceilings; (2) embedded piping for walls; (3) embedded piping for floors; (4) air heated ceilings, walls, or floors; (5) electrically heated ceilings, walls, or floors. ` Embedded Piping for Ceilings . When piping is embedded in ceilings, the construction used is.generally one of the following: a. Pipe or tube is embedded in the lower portion of a con crete slab, generally very close to its lower surface. If plaster is to be applied to the concrete, the piping may be placed directly on the wood forma. If the slab is to be used without plaster finish, then the piping should be iastailed not less than X in. above the undersurface of the slab. Fig. 1 shows this method of construction. The minimum coverage must be in compliance with the local building code requirements. APPLICATION METHODS Rg. 1 .... Coils in Structural Concrete Slab The great majority of panel installations of the past 50 years (which is the period of the modem utilization of this method of heating) have used warm water as the heating medium which is circulated in embedded piping. More recently, the use of warm air ducts, and embedded electrical heating elements, has come into favor, especially where specific local factors have influenced such use. Steam has been used only occasionally because of the problems which result from its higher temperature. When the heating medium is warm water, both, ferrous (steel or wrought iron) or non-ferrous (generally copper or aluminum) pipe or tube are used widely in ceiling, wall, or floor panel construction. Tube sizes used are X, H, aod X in. OD, while piping is generally X, H, or 1 in. IPS. Where coils are embedded in concrete or plaster, no threaded joints should be used for either pipe coils or mains. The construction should be of all-welded type. Changes in direc tion should be made by bending the pipe itself, rather than by use of fittings. Solder-joint fittings are used for nonferrous heating coils and piping. It is recommended that a medium temperature solder of 95 percent tin--5 percent b. Pipe or tube is embedded in a metal lath and plaster ceiling. If the lath 'is suspended to form a hung, ceiling, both the lath and the heating coils are securely wired to the sup porting members in such a way that the lath is below, but in good contact with the coils, as shown in Fig. 2. Plaster is then applied to the metal lath, care being taken to embed the coil, as shown in Fig. 2. c. Copper tube of the smaller diameters is attached to the underside of wire lath or gypsum lath. Plaster is then applied to the lath to embed the tube, as shown in Fig. 3. d. Other forms of ceiling construction are prefabricated panels of metal, composition board, wood paneling, etc., hav ing warm water piping, tube, or channels built into the panel sections. Coils are usually of the sinuous type, although someheader or grid type coils have been used in ceilings- Coils may be of either ferrous or non-ferrous' pipe or tube, with coil pipes spaced from 4X to 9 in. on centers, depending on the re quired output, pipe or tube size, and other factors. Where plastering is applied to pipe coils, a standard three- coat gypsum plastering specification1 is followed, with a minimum of X m* of cover below the tubes when the tubes 420 CHAPTER 30 1959 Guide SCRATCH COAT PLASTER CEILING BELOW JOISTS Fig. 2 .... Coils in Plaster Above Lath are installed below the lath. Generally, the surface tempera ture of plaster panels should not exceed 120 F, and this is usually met by limiting the water temperature in the pipes or tubes in contact with the plaster to a maximum tempera ture of 140 F. Insulation should be placed above the coils to reduce the reverse loss which is the difference between the heat supplied to the coil and the net useful output to the heated room. In order to protect the plaster installation and to assure proper air drying of the plaster, it is recommended that no heat be applied to the panels for two weeks after all plaster ing work has been completed. When the system is started for the first time, the water supplied to the panels should be at a temperature not more than 20 deg above the pre vailing room temperature at that time (but not in excess of 90 F). Water should be circulated at this temperature for about two dayB. Then the water temperature should be increased at a rate of approximately 5 deg increase per day to 140 F. During the air-drying and preliminary warming-up periods, adequate ventilation should be provided to carry off moisture from the panels. No paint or paper should be applied to the panels until these periods have been completed. No paint or paper should be applied while the panels are being operated. After paint and paper have been applied, a further shorter warm-up period, similar to that for the first time starting, is also recommended.. Embedded Piping for Walls Although not so universally used as ceiling panels, wall panels may be constructed by any of the methods outlined for ceilings. Embedded Piping for Floors The construction for piping embedded in floors will depend upon whether (a) the floor is laid on grade, or (6) the floor is above grade. a. Both ferrous and non-ferrous pipe and tube are used in floor Blabs which rest on grade. The coils are constructed as either sinuous-continuous pipe coils, or arranged as header coils with the pipes spaced from 6 to 18 in. on centers. The coils are generally installed with IK to 4 in. of cover above Fig. 4 .... Coils in Floor Slab on Grade the coils. It is recommended that insulation be used to reduce the perimeter and reverse losses. Fig. 4 shows the application of pipe coils in slabs resting on grade. Coils should be em bedded completely and should not rest on an interface. Any supports used for positioning the heating coils should be non absorbent and inorganic. It is suggested that reinforcing steel, angle iron, pieces of pipe, or stone concrete mounds be used. No wood, brick, concrete block, or similar materials should be used for support of coils. Generally, a waterproofing layer is desirable to protect insulation and piping. . b. Where the coils are embedded in structural load support ing slabs above grade, construction codes may affect their position. Otherwise, the coil piping is installed in the same manner as described for slabs resting on grade. c. A warm-up and start-up period for concrete-panels should be similar to that outlined tor plaster panels. Fig. 5 .... Warm Air Plaster Celling Construction Fig. 6 .... Warm Air Floor Panel Construction Panel Heating 421 Air-Heated Ceilings, Walls, and Roars Several methods have been devised to warm the interior room surfaces by circulating heated air through passages VvohinH the** surfaces. In some cases, the heated air is re circulated in a closed system. In others, all or a part of the air is through the room on its way back to the furnace to provide supplementary heating and ventilation.' Figs. 5 and 6 indicate two common types of construction. Care must be exercised to assure compliance with any building codes that might apply. (See also section on Warm Air Ceiling Panel Systems in Chapter 18.) Electrically Heated Ceijings, Walls, or Floors Several different forms of electric resistance units are available for heating the interior room surfaces. These include: (1) resistance cables that may be embedded in a mannpr girnilar to hot water piping in concrete or plaster; (2) prefabricated electric heating panels to be attached to room surfaces; and (3) electrically heated fabrics or other materials for application to, or incorporation into, finished room surfaces. Figs. 7 and 8 indicate two methods of in stallation. The constructions of electric panels for ceilings, walls, and floors are described in greater detail in Chapter 17, Electric Heating. HEAT OUTPUT FROM PANa SURFACES A heated panel transfers heat to a room by convection and radiation. In the following paragraphs,- the two transfer mechanisms are first considered separately and then com bined to facilitate design calculations. Radiation Transfer . The radiation transfer can be evaluated by means of the Stefan and Boltzmann equation: . ,-ow.p'-(0] 0) where q, heat transfer by radiation, Btu per (hour) (square foot). T, -- temperature of panel heated surface, Fahrenheit, absolute. ... fig. 7 .... Ejectric Heating Cables in Plaster fig. 9 .... Heat Output by Radiation T, -- mean radiant temperature of all unheated surfaces, Fahrenheit, absolute. ' *= the configuration factor (dimensionless). P, m the emissivity factor (dimensionless). . A combined configuration and emissivity factor - for a simple, box-like room- in which there is a uniformly heated ceiling, floor, or wall, all other, surfaces are at another tem perature, and all surfaces are perfectly diffusing is given by HotteP as: F, - PtF, (2) ~ 0 + r! Gr 0 where . - ` pt =* combined configuration and emissivity factor. Fi-t * view factor ** 1.0. t\ and e% a emissivities of the surfaces. Ai and Aj = areas of the surfaces. In practice the emissivity of conventional, non-metalhc, non-reflecting surfaces will be found to be about 0.9. When Jiia emissivity is used in Equation 2, the combined factor will be found to be about 0.87 for most rooms. Substituting this value in Equation 1, the constant becomes about 0.15 and the equation can be rewritten: fig. 6 .... Prefabricated Electric Panel where . ip = temperature of panel surface, Fahrenheit. AUST = area-weighted average temperature of unheated surfaces in room, Fahrenheit. - The actual radiation transfer in a room may be somewhat different from that given by Equation 3 because of non uniform temperatures, irregular room surfaces, variations in 422 CHAPTER 30 1959 Guide emissivity of materials, etc. It is generally' agreed, however, that the equation is accurate to within 10 percent when used in conventional heating and cooling calculations. Tests4 conducted in the ASHAE Environment Laboratory* showed that the value of the constant of Equation 3 was 0.132 in the test room. The design information in this chapter is based on that value of the constant. Radiation exchange calculated from Equation 3 is given in Fig. 9- The values apply to either ceiling, floor, or wall panel radiation output. Convecrtori"Trdnsfer . Convectioorvafnes of heat transfer are not easily estab lished. Convection in a panel heated space is usually con sidered to be of the natural type, that is, air motion is gen erated by the'warming (by conduction), of the boundary layer of air which starts moving as soon as its temperature exceeds that of the surrounding- air. In practice, however, there are many factors which interfere with or affect natural oonvection. The configuration of the room- and the space' connected to it and the variation in temperature throughout the two spaces determine the natural convection. Infiltration, ventilation, and' the movement of persons may serve to introduce seme forced convection which can disturb the natural process. The laboratory approach has been to measure the natural .convection in a bare, box-like -room which is sealed against infiltration and in which all surfaces,. except the heated panel, are at one uniform temperature. Convection was also measured with varying amounts of infiltration and a cor rection determined for use in practical problems.*'7 Tests4 conducted in the ASHAE Environment Laboratory indicated that the natural convection from floors and ceilings can be calculated from Equations 4 to 9 which follow. Natural convection from heated ceiling - - t.)>-* ? 0.041 D.'** (4) NOTE: For condition* other than ISO F coiling and 65 F AUST (changes not greater then 40 F In colling teotp and 20 F In AU ST) For each (OF increooo in coiling temp, increases 15X -- For each IOFdecrease in celling temp, a^ decreose* I5X For each IOF increase in AUST, aq, decreose* 5% ____ 1____ 1 1 -1____ 1 O F Infiltration Air Tnp-> o S' / A. 40 F Infiltration Air Temp Ceding erf 120 F, <x0 other nrfmti at 6S F (24^ x 12 x 8 ft Ugh room} Fig. II .... Additional Heat Flow from Ceiling due to Infiltration Air4 '- Natural convection from heated floor %- $, 0.39 D*** Natural convection from heated wall (b ~ Qn ? H*- (5) (6) q* -- heat transfer by convection, Btu per (hour) (square foot). . ... = temperature'of panel surface, Fahrenheit. U -- temperature, of the air,- Fahrenheit. D, = equivalent diameter of panel (area X 4 -f- perimeter), feet. H " height of wall panel, feet. Fig. 10 .... Heat Output by Convection from Floor and ' - , Ceiling Panels Floor 65 F, a0 other tvrfom 65 F (24^ x 12 x S ft Ugh room) Fig. 12 .... Additional Heat Output from Floor due to Infiltration Air Panel Heating 423 Fig. 13 .... Relation of Inside Surface Temperature to Overall Coefficient of Heat Transfer Measurements of panel performance in furnished test rooms which did not have uniform temperature surfaces showed variations that are not large enough to be significant in heating practice.* Other tests* established that the effect of room size was usually insignificant. The convection equations can therefore be amplified to: Natural convection from heated ceiling ' ' qt = 0.021 (4 - (.)* Natural convection from heated floor 4. = 0.32 (fp - 4)lJ1 ' (7) .' -- (8) Natural convection from heated wall -- q. - 0.26 - 4)1-** (9) Fig. 10 shows panel convection outputs calculated from these equations. . Infiltration and ventilation increase the convection from panels. FigB. 11 and 12 show the amount of increase A?, observed in the ASHAE Environment Laboratory.4-7 Equa tions 7 and 8 and Figs. 11 and 12 were used in the develop ment of the design data for this chapter.. ' Combined Heat Transfer The heat transfer from a panel to a room can be deter mined by adding the radiant heat transfer horn Fig. 9 to the convective heat transfer from Fig. 10. Use of Fig. 9 requires the calculation of the AUST, the area-weighted average surface temperature of the unheated surfaces in the room. In calculating AUST, the surface temperature of inside walls is assumed to be the same as the room air temperature. The surface temperatures of outside walls and exposed floors or nwlinga can be obtained from Fig. 13 for a 70 F room air temperature. Corrections for other temperatures may be obtained from Fig. 14. The combined heat transfer for ceiling panels .'and floor panels in rooms in which the air temperature is 70 to 76 F can be read directly from Figs. 15 and 16, respectively. These two diagrams apply to roqms- in which the AUST . '- : v 4 -- indoor air temperature 4 -- inside wall surface temperature baaed on 4 TM 70 P 4' = actual inside vaU surface temperature - : fig. 14 ..:. Inside Wall Surface Temperature Correction for Air Temperatures Other Than 70 F does not differ greatly from room air temperatures. Teste** ? showed that the two temperatures are normally nearly equal. Effect of Floor Coverings Floor coverings may have a pronounced effect upon the performance of a floor panel system. The added thermal resistance of the floor covering causes a reduction in upward heat flow, and increases the heat flow to the underside of the fig. 15 .... Ceiling Panel Design Graph Showing Panel ' ' Surface Temperature and Mean Water................... ' . '' -Temperature vs Output Downward 424 CHAPTER 30 1959 Guide Rg. 16 .... Floor Panel Design Graph Showing Panel Surface Temperature and Mean Water Temperature vs Output Upward .. Rg. 17 .... Downward and Edgewise Heat Loss Coefficient for Concrete ' Floor Slabs on Grade slab. 'To maintain a given upward heat flow after a floor covering has been added, the temperature of the heating medium must be increased. Data on the thermal resistance of common floor coverings are given in Table 4, and the application of the data is illustrated in Example S. Where covered and bare floor panels exist on the same system, it is necessary to maintain the water temperature high enough to satisfy the covered panels, and balance the system by throttling the flow to the bare slabs. When possible, it is desirable to divide the covered and bare panels into separate zones. Panel Heat losses '- t i ' Heat transferred from the upper surface of ceiling panels, the back surface of wall panels, the underside of floor panels, or the edges of any panel is considered a panel heat loss. Panel heat losses are part of the building heat loss if the heat is transferred outside of the building. If the heat is transferred - to another heated space, the panel loss is a source of heat for tire space and is not a part of the building heat loss. In either case, the magnitude of the panel loss should be deter mined. Panel heat loss to the space outside the room should be kept to a reasonable amount by insulation. Panel.heat loss to heated spaces may require reduction-by insulation if tire amount of heat transferred is. excessive or if objectionable temperatures will be developed. For example, a floor panel may overheat the basement below and a ceiling panel may cause the temperature of a floor surface above it to be too high for comfort. ~ The heat loss from most panels can be calculated by using the coefficients given in Chapter 9, Heat Transmission Coefficients of Building Materials. These coefficients should not be used to determine the downward heat loss from panels built on grade because the heat flow from them is not uni form."' 11 a The heat loss from panels built on grade can be estimated from fig. 17. ' ' DESIGN OF PANR HEATING SYSTEMS Design Steps Panel design requires specification of the following: panel area, size and location of the heating elements in the panel, insulation on the reverse side and edge of the panel, required input to panel, and temperature, of the heating elements. The procedure is summarized as follows: 1. Calculate the hourly rate of heat loss for each room. 2. Determine the available area for panels in each room. 3. Calculate the required unit panel output. 4. Determine the required panel surface temperature. 5. Select the mpAna of heating the panel and the sire and -location of the heating elements. - 6- Select the insulation for the reverse side and edge of the panel. - 7. Determine the panel beat loss and the required input to the panel. - 8. Determine the other temperatures which are required or developed. - 9. Design the system for heating the panels in accordance with conventional practice. In the steps outlined.for design, the effect of each assump tion or choice on oomfort should be considered carefully. Tests are now being made at the ASHAE Research Lab oratory to identify, and measure the factors which contribute to comfort and to establish comfort design principles. Until the results are available the following general rules may be followed: . 1. Place panels near the cold areas where the heat losses occur. ' 2. Do not use high temperature ceiling panels in very low ceilings. 3. Keep floor temperatures at or below recommended limits. Panel Heating . 425 Warm Water Panels This section contains a amplified procedure for the thermal design of water-heated panels for use in residences and commercial buildings. The procedures are based primarily on the experimental data obtained at the ASHAE Research Laboratory. This work has been reported in a series of research papers which are fisted in the references and bibliog raphy at the end of this chapter. A panel designed by these procedures will maintain the desired room air temperature for the selected outdoor con ditions. Room air temperature is the selected criterion of comfort. The design procedure is restricted to situations in which the area-weighted average temperature of unheated surfaces of walls, glass, and floor or ceiling does not differ greatly from room air temperature. Room-scale tests, which simulated various conditions of construction and outdoor temperature, have shown that this near-equality of the two temperatures normally prevails. . The procedures are applicable within the following range: Outdoor design conditions: Temperatures as low as --30 F. Room air temperature: 70 to 76 F. Air changes: No more than two air changes per hour. Room dimensions: Rooms having normal proportions; ceiling height between 7 and 12 ft. Room construction: Any type of wall construction and any amount of glass area. (Both, however, have an effect upon comfort.) Conventional interior finishes and furnishings. Design Examples Id the design examples which follow use is made-of the letter symbols shown in the table Letter Symbols for Examples of Design Methods. Letter Symbols for Examples of Design Methods Ap = panel area, square feet. ' Ci = coefficient of heat transfer from the upper surface of the concrete slab which forms the ceiling panel to air above pane! at point 4 , Btu per (hour) (square foot) (Fahrenheit degree temperature difference between panel surface and air). Ci *= coefficient of heat transfer from lower surface of con crete slab to air below the panel at point h , Btu per (hour) (square foot) (Fahrenheit degree temperature difference between panel surface and air). C -- coefficient of downward and edgewise heat loss of exposed slab, Btu per (hour) (linear foot of exposed slab perimeter) (Fahrenheit degree difference be tween concrete surface and outdoor air). ' P = length of exposed edge of slab, feet. qi = downward heat flow from panel, Btu per (hour) (square foot). qt a apportioned downward and edgewise heat flow from . panel, Btu per (hour) (square foot). " upward heat flow from panel, Btu per (hour) (square foot). n -- total thermal resistance of panel to downward heat flow, (Fahrenheit degree) (hour) (square foot) per Btu. tie *= thermal resistance of material between the under side of the concrete slab and the ceiling surface be . low, (Fahrenheit degree) (hour) (square foot) per Btu. tde = thermal resistance of bare concrete panel to down ward heat flow, (Fahrenheit) (hour) (square foot) per Btu. rs -- total thermal resistance of panel to upward heat flow (Fahrenheit degree) (hour) (square foot) per Btu. r -- thermal resistance of floor covering, (Fahrenheit degree) (hour) (square foot) per Btu. fa) =* thermal resistance of bare concrete slab to upward heat flow, (Fahrenheit degree) (hour) (square foot) per Btu. U " design room air temperature, Fahrenheit. Up * outdoor design air temperature, Fahrenheit. - 4 9 air temperature above or below panel at point to which U, Ci, or C* is taken, Fahrenheit. U = inlet water temperature, Fahrenheit. 4 = outlet water temperature, Fahrenheit. U, = mean water temperature, Fahrenheit. l__ maximum water temperature permissible for a given construction, Fahrenheit. Li__-- design mean water temperature (selected for each zone), Fahrenheit. - U " panel surface temperature, (exposed surface) Fahren- - heit. (. D surface temperature of top of concrete slab, Fahren heit. U = overall coefficient of beat transfer for the given con struction between room air and the point U , Btu per (hour) (square foot) (Fahrenheit degree temperature difference). Procedure for Plaster Ceiling Panels" The procedure for designing a plaster ceiling panel will be illustrated by Example Example Three rooms, A, B, and C, are to have a common water supply temperature; that is, they represent a single rone. They are to be maintained at 72 F air temperature when the outdoor air temperature is zero F. The ceilings of rooms A and B have floors above them with the space heated to 72 F and an air-to-air U value of 0.25 Btu per (hr) (sq.ft) (F deg). The ceiling of room C has insulation in the joist spaces and an uninsulated attic space with a combined U value of 0.05 from room C to outdoor air. . Step 1. Heat Loss . Calculate the heat loss of each room by methods outlined in Chapter 22, Heating Load, but do sot include any heat loss through the area covered by the panel. * . Room dimensions and calculated heat losses are as follows: - Room Room A Room B Room C - Dimensions Feet . Heat Loss Btu per hour 11 x 12 x 8 11 x 12 x 8 15 x 21 x 8 6300 2500 8000 Step I. Required Panel Output Divide the heat loss of each room by the maximum ceiling area in the room which can be used as a heating panel. The result is the minimum beat output per square foot of panel that will satisfy the requirements of the room. The panel that requires the highest output per square foot will generally control the design, because the temperature of the fluid in the system must be high enough to produce the required out- 426 CHAPTB? 30 put from that panel. The required panel output is given in the following table. Available Panel Abba Sq Ft Reqotbed -Panel Output, 94 Btu/(hr) (sq ft) Room A 132 sq ft 6300 ------ = 47.7 132 Room B 127 sq ft 1959 Guide Room C 306 sq ft Step 8. Panel Surface Temperature From Fig. 15 find the panel surface temperature needed to yield the required heat output to each room, using the output determined in Step 2 and the design room air temperature. This use of Fig. 15 for Room A is illustrated in Fig. ISA. Rg. 18 .... Upward Heat Row from Plaster Ceiling Panel The values of for Rooms A, B, and C as determined from Fig. 18 are as follows: Room A B C U 0.25 0.25 0.05 4-4 F Deg 42 20 97 - 9- : Btu/(hr)(sq ft) 12.5 6.0 5.0 Rg. 15A .... Determination of Panel'Surface Temperature for Room A from Rg. 15 '' The values of 4 determined for Rooms A, B, and C are as follows: . Room At," 114 F . . Room B 1, -- 92 F *Room C ty = 97 F Step 4 Upward Heal Plow Determine the upward heat flow from each panel using Fig. 18. The upward heat flow must be determined in order to ob tain the downward panel resistance and to select the proper size of boiler. The use of Fig. 18 is illustrated for Room A in Fig. 18A. Note that the U values shown on Fig. 18 are those Step 6. Downward Panel Resistance Assume tentative pipe or tube spacings for the panel con struction to be used from those listed in Table 1, choosing the closer spacings when higher outputs are required. Also in Table 1 find the resistance of eacn panel (r*), using heat flow ratios calculated from the flow rates determined in Steps 2 and 4, interpolating as required.. - Room Spacing Heat Flow Ratio Resistance (r*) (Inches) 8 --A 0.35 B 9 157? " '30 0.90 C9 ' 019 0.85 Step 6. Mean Water Temperature For the required panel output (94) found in Step 2, the panel resistance (rj) found in Step 5, and the room air temperature (4), find the mean water temperature (4) from Fig. 15. This use of Fig. 15 is illustrated in Fig. 15B. * Rg. 18A .... Determination of Upward Heat Row for Room A from Rg. 18 for the entire structure of which the panel is a part and are taken from room air (temperature, 4) to air above the panel (temperature, 4) and for tnat reason 9.1/(4 -- 4)- U values may oe obtained from Chapter 9, Heat Transmission Coeffi cients of Building Materials. . Rg.15B .... Determination of Mean Water Temperature for Room A from Rg. 15 . Panel Heating Table 1 .... Thermal Resistance of Plaster and Metal Ceiling Panels 427 Values of for Rooms A, B, and C as determined from Fig, 15 are as follows. ' Room A 119 F ~ 131 F, Room B 4 = 110.5 F, Room C 4u *= Step 7. Design Mean Water Temperature ' Select a single design mean water temperature (4m) for each group.of rooms which is to comprise a zone, choosing the highest mft&n water temperature (4) of the group subject to the following: . a. If ^ is equal to or less than 4u (see No menclature and Table 1, this mean water temperature (4) is an acceptable design mean water temperature (4**)- Pro ceed to Step 8. -- b. If 4> + g ^ * Sreater than L... , go back to Step 5 and select a panel construction which has a lower panel re sistance (r*) 1 This ean be accomplished by either or both of the following: 1. Reducing the tube spacing, ' 2. Decreasing the upward heat flow (9.) by providing ad ditional insulation above the panel. If the required mean water temperature is still too high apply either or both of the following: 1. Reduce the heat loss of the room, 2. Provide supplementary heating. In Example 1, assume 4 -- 4 " 15 F deg and t--- -- 140 F, Then since C* " 131 F, 4. + (4 -- 4) " 138.5 F and is less than L.. . Thus 131 F can be used as the design mean water temperature 4__. Step 8. Design Panel Output From Fig. 15, find the panel output (94) for design mean water temperature (4m), room air temperature (4), and panel resistance (*v). Fig. 15C shows how Fig. 15 is used to find 94 for Room B in this step. Rg. 15C .... Determination of Design Panel . Output for Room B from Rg. 15 The mean water temperature (4) found for Room A in Step 6 was used as the design mean water temperature (4m). The panel output for Room A which was determined in Step 2 is therefore tne design panel output for this room. Design panel outputs for Rooms B and C can be found from Fig. 15 lining the design mean water temperature (4m)- Room Design Panel Output (94) Btu per (hr) (sq ft) A 47.7 B 32.5 C 33.0 428 CHAPTER 30 1959 Guide Step 9. Design fanei Area .. Divide the room heat toes found in Step 1 by the design panel output found in Step 8. Room A B C Design Panel Area (A,) Sq ft 132 (Unchanged from Step 2) 77 242 Step 10. Total Panel Output Add the beat flow upward (?.) to the design panel outpnt (g*) and multiply by tne design panel area to obtain the total panel output. If the design panel output is different from the panel output (?*) used in Steps 3 and 4, the heat flow upward (g) should be redetermined. Room 9- Total 9* 9* + 9* A, Panel Output 4,(9* + qs) Btu/hr A 12.5 47.7 B 9.5f 32.5 C 5.5t 33.0 t redetermined 60.2 42.0 38.5 132 77 242 7946 3234 9317 Step 11. Fluid Circuit Design the fluid circuit (panel piping and mains) for a tem perature drop of 10 to 20 r deg between the water inlet and outlet of the panel (see Chapter 28, Hot Water Heating Sys tems). Step IB. Boiler Site Size the boiler according to method contained in Chapter 35, Heating Boilers, Furnaces, and Space Heaters. The net Btu rating of the boiler should equal or exceed the total out put of all panels plus any other loads on the boiler. Procedure for Metal Ceiling Panels11 Follow the procedure for Hot Water Plaster Ceiling Panels. Procedure for Concrete Ceiling Panels1* Concrete ceiling panels are distinguished from concrete floor panels in intermediate floors by the position of the tubes in the concrete slabs (see Tables 2 and 3). Both types of panels have heat outputs in both directions in amounts - determined by the thermal resistances and tire temperature differences in the two directions. The effect of both outputs on heating requirements of the spaces and the comfort of the occupants should always be considered. (See section on Procedure for Concrete Floor Panels--Intermediate Slab.) The procedure for hot water plaster ceiling panels cannot be applied in its entirety to concrete ceiling panels because some of the simplifying assumptions regarding the upward heat flow from plaster panels are not valid for concrete panels. The necessary modification of the plaster ceiling panel procedure is as follows: Step 1. Heat Loss Follow the procedure for Plaster Ceiling Panels, Step 1. Step S. Required Panel Output Follow the procedure for Plaster Ceiling Panels, Step 2. (able 2..... thermal (resistance ot Concrete tailing Panels Panel Construction /MOUCM WES 1 \ otcovt*"" 1 Thereof Resistance (F deg)(sq fl) (hr) per Sto Hoot Row Ratio In. 0 0.5" 1.0" UP down up dawn up dawn 6-m. Concrete Slob--1-in. cover r- U r re (nom.) nonferrous tube 9 3.6 0.30 0.9 0.35 0.7 0.45 12 5.1 0.35 1.1 0.45 0.9 0.55 }-in. (nom.) ferrous pipe or K*in. (nom.) nonferrous tube 9 2.6 0.25 0.7 0.30 0.6 0.35 12 4.0 0.30 0.9 0.40 0.8 0.50 (nom.) ferrous pipe or 1-in. (nom.) nonferrous tube 9 2.1 0.20 0.6 0.25 0.6 0.30 12 3.3 0.30 O.fi 0.35 0.7 0.40 15 4.5 0.35 1.0 0.45 0.8 0.55 1-in. (nom.) ferrous pipe 9 1.6 0.20 0.5 0.25 0.5 0.25 12 2.6 0.25 0.7 0.30 0.6 0.35 .15 3.6 0.30 0.9 0:40 0.7 0.45 8-in. Concrete Slab--1-tn. Cover H-in. (nom.) nonferrous tube 9 3.6 0.30 1.0 0.35 0.8 0.40 12 5.2 0.35 1.2 0.45 1.0 0.55 (nom.) ferrous pipe or %-in. (nom.) nonferrous tube 9 2.9 0.25 0.9 0.30 0.8 0.35 12 4.0 0.30 i.i 0.40 |0.9 0.45 Ji-in. (nom.) ferrous pipe or 1-in. (nom.) nonferrous tube 9 2.2 0.20 0.8 0.30 0.7 0.30 12 3.3 0.30 l.C 0.35 0.8 0.40 15 4.3 0.35 1.1 0.40 0.9 0.50 1-in. (nom.) ferrous pipe 9 1.7 0.20 0.7 0.25 0.7 0.25 12 2.7 0.25 0.9 0.30 0.8 0.35 15 3.7 0.30 1.0 0.40 0.9 0.45 * Any ceiling pane) slao acts ss * Boor pane) to the extent of it* upward beat flow. If the upward beat Bow ta high and the apace above is occupied, check floor eurfaoe temperature (or poeaible (oot diecomlort (aee Reference 7). AUo check eSect on heating requirement* of the apace above. It is oot good practice to have the major portion of the upper room'* heetinc requirements supplied by the upward beat flow of a ccoling panel below. Step S. Panel Surface Temperature \ Follow the procedure for Piaster Ceiling Panels, Step 3. Step 4- Upward Heat Flow Estimate a. If the upper surface of the slab is exposed to form a floor, find the heat flow upward from Fig. 16, using the panel surface temperature (t) found in Step 3, and the air tempera ture of the space above. b. If the upper surface of the slab is not exposed, use the equation: 9. - C,(t - t,) (10) Panel Heating Table 3 .... Therraal'Resisfance of Bare - Concrete Floor Panels Spocpanel Construction Thermal Renrfarrce IF degllrq ftllhri/Bta Heat Row Ratio (fr/qe 1 3 5 10 4-in. Concrete Slab--2-in. Cover up down up down up down up down r,, te r,, *it r ti. Tet Tit }j-in. (nom.) nonferrous tube 9 0.57 0.52 0.46 0.84 0.43 1.17 0.42 1.97 12 0.73 0.68 0.58 1.16 0.54 1.65 0.51 2.86 M~in. (nom.) ferrous pipe or X-in. (nom.) nonferrous tube 9 0.49 0.42 0.41 0.66 0.39 0.90 0.38 1.80 12 0.63 0.55 0.50 0.93 0.48 1.30 0.46 2.35 6-u>. Concrete Slab--2-iq. Cover X-in. (nom.) nonferrous tube 9 0.59 0.70 0.47 1.05 0.45 1.39 0.43 2.25 12 0.78 0.90 0.60 1.40 0.56 1.97 0.54 3.21 %-in. (nom.) nonferrous tube 9 0.51 0.61 0.43 0.87 0.41 1.13 0.40 1.78 12 0.68 0.78 0.54 1.23 0.51 1.63 0.49 2.61 K-in. (nom.) 9 0.47 0.55 0.40 0.77 0.39 0.98 0.38 1.50 ferrous pipe 12 0.63 0.71 0.50 1.07 0.48 1.44 0.46 2.36 1-in. (nom.) nonferrouB tube or 1-in. (nom.) fer rous pipe 12 0.59 0.66 0.48 0.98 0.46 1.30 0.45 2.11 15 0.73 0.83 0.57 1.21 0.54 1.73 0.61 2.74 Step 6. Upward and Downward Panel Resistance Follow the procedure for Plaster Panels, Step 5, using Table 2 to find both resistances (ru and n). Step 6. Mean Water Temperature and Upward Heat Flow a. Follow the procedure for Plaster Panels, Step 6. b. find the heat flow upward from the panel (9,) from Fig. 16. Add to the thermal resistance of the slab to upward heat flow (r,,), the resistance to beat flow (rM) of any material between the upper surface of the slab and the space above to obtain the resistance (r,) to be used in Fig. 16. The mean 'water temperature (U.) found and the air temperature of the space above the panel are the other two factors to be used. Step 7.`Design Mean Water Temperature Select the highest mean water temperature (L) as the de sign mean water temperature (<*)- Step 8. Design Panel Output Follow the procedure for Plaster Panels, Step 8. Step 9. Design Panel Area . Follow the procedure for Plaster Panels, Step 9. 429 Step 10. Total Panel Ouipui Follow the procedure for Plaster Panels, Step 10. Step 11. Fluid Circuit Follow the procedure for Plaster Panels, Step 11. Step IB. Boiler Size Follow the procedure for Plaster Panels, Step 12. ' Procedure for Plaster Wall Panels A design graph has not been prepared for wall panels but a design can be approximated using the equations of heat transfer from walls together with the thermal resistance properties of plaster ceilings from Table 2. The procedure for Plaster Ceiling Panels is used as a guide. Step 1. Heat Loss Follow the procedure for Plaster Ceiling Panels, Step 1. Step B. Required Panel Output Follow the procedure for Plaster Ceiling Panels, Step 2. Step S. Panel Surface Temperature Assume a trial panel surface temperature and determine the resulting heat output from Figs. 9 and 10 as explained in the accompanying section of the test. (Additional neat flow due to the infiltration can be estimated from Fig. 12, if de sired.) Assume successive trial panel surface temperatures until the temperature is found at which the combined heat transfer from the panel equals the output determined in Step 2. . Step 4. Reverse-Side Heat Flow Follow the procedure for Plaster Ceiling Panels, Step 4. Step 6. Panel Resistance ' Follow the procedure for Plaster Ceiling Panels, Step 5. Step 0. Mean Water Temperature For the required panel output found in Step 2, the panel resistance found in Step 5, and the room air temperature, calculate the required mean water temperature as follows: ' " tp + t*(&) (11) Step 7. Design Mean Water Temperature Follow the procedure for Plaster Ceiling Panels, Step 7. Step 8. Design Panel Output From equations, Step 6, and Figs. 9 and 10 find the panel output for design mean water temperature (*_ by successive trials. Step 9. Design Panel Area Follow the procedure for Plaster Ceiling Panels, Step 9. Step 10. Total Panel Output Follow the procedure for Plaster Ceiling Panels, Step 10. Step 11. Fluid Circuit Follow the procedure for Plaster Ceiling Panels, Step 11. Step IB. Boiler Size Follow the procedure for Plaster Ceiling Panels, Step 12. Procedure for Hot Water Concrete Floor Panels (Slab-On-Grade)u The procedure for designing a concrete floor panel (slabon-grade) will be illustrated by Example 2. Example B: Three rooms, A, B, and C, are to have a com mon water supply temperature; that is, they represent a single sone. They are to be maintained at 72 F air temperature % 430 CHAPTER 30 1959 Guide when the outdoor air temperature is zero F. The floors in the three rooms are covered with heavy wall-to-wall carpeting, without a pad. Insulation which has a conductance of 0.4 Btu per (hr) (sq ft) (F deg) is placed along the edge of the slab and extends downward 2 ft below it. Step i. Heat Los* Calculate the heat loss of each room, following the recom mendations contained in Chapter 12, Heating Load, but do not include any beat loss through tbe area covered by the pane). If very large rooms are involved, the rooms should be sub divided into areas having somewhat gimil&r heat requirements, i.e., separate the intenor areas requiring little or no heat input, from the exterior areas directly influenced by outdoor weather conditions. Each such area should then be treated as a separate room for the purpose of design. Room dimensions, exposure, and calculated heat losses are as follows: Rook Dimensions Feet Exposed Wall Feet Heat Loss Btu per hr A* 11 x 12 x 8 23 B 11 * 12 x 8 12 C 15 x 21 x 8 21 3300 2500 8000 * Compare with Boom A of BbimpU l. The rooma are tha him except that in this example a lower best km is Boomed to permit the room to be heated by a Boor panel alone without developing an inadmiambly high panel uzfaee temperature (Step t). The lower heat lorn i* presumably the result Table 4 .... Thermal Resistance of Floor Coverings ` Description Beshtaace, rM (f rfegKMUq m/ttv Bare concrete, no covering Asphalt tile Rubber tile 0.00 0.05 . 0.05 Light carpet Light carpet with rubber pad Light carpet with light pad Light carpet with heavy pad 0.6 1.0 1.4 1.7 . Heavy carpet - Heavy carpet with rubber pad Heavy carpet with light pad Heavy carpet with heavy pad 0.8 1.2 1.6 1.9 Step 4- Downward and Edgewise Heat Flow a. Determine the temperature of the surface of the concrete slab ((,) by adding to the panel surface temperature, the tem perature difference caused by tbe thermal resistance of the floor covering, if any: U - Ip + (ff. X f) (12) The value of (rM) for various floor coverings is given in Table 4. Step B. Required Panel Output _ Divide the heat loss of each room by the maximum floor area in tbe room which can be used as a heating panel. The result is the minimum heat output per square foot of panel that will satisfy the requirements of the room. The panel that, requires the highest output per square foot will generally control the design, because the temperature of tbe water in the system must be high enough to produce the required output from that panel. Boom A B C Available Panel Abba Sq ft 132 127 306 Required Panel Output (5.) Btu/(hr) (sq ft) 25.0 19.7 26.1 Step S. Panel Surface Temperature From Fig. 16 find tbe panel surface temperature needed to yield the required heat output to each room, using the output determined in Step 2 and the design room air temperature. Floor pane) surface temperatures in excess of about 85 F are not recommended because of the probability of discomfort to the feet. If the required beat output cannot be obtained from an 85 F floor panel, heat losses should be reduced or sup plementary heating should be provided. Room A B C Panel Surface Temperature (4) 85.0 F 82.5 F 85.3 F Room 4 <fc r,, 4 A 85.0 F 25.0 0.8 105.0 F B 82.6 F 19.7 0.8 98.3 F C 85.3 F 26.1 0.8 106.2 F b. Determine the downward and edgewise heat loss co efficient C* from Fig. 17 for the insulation to be used. Insula tion with a conductance of 0.4 Btu per (hr) (sq ft) (F deg) ex tending two feet below the slab results in a slab downward and edgewise beat loss coefficient of 0.97 Btu per (hr)(ft) CF deg) c. Apportion the downward and edgewise heat loss uni formly across the panel as follows: P X CiO. ~ U 9* A, 03) Room P t. - 4. A, 9*. A 23 105.0 F . 132 17.7 B 12 98.3 F 127 9.0 C 21 106.2 F 306 7.1 Step 6. Upward Panel Resistance . Assume a tentative pipe or tube sixe and a spacing for each panel, choosing closer spacings and larger pipe or tube when higher heat outputs are required. From Table 3, find the ther mal resistance (rM) of the slab of each panel, using heat flow ratios (gn/q*,) calculated from the flow rates determined in Steps 2 ana 4, interpolating as required. To tbe slab resistance (rM), add the resistance oT the floor covering (rM, Step 4) to obtaio the panel resistance to upward heat flow (ra). Panel Heating 431 Pipe ob Tube Room Spacing 9-/94. 25 A 9 in. ^7 - 141 rH 0.47 rv r. 0.8 1.27 - 7.19 B 12 in. 0.55 0.8 1.35 9.0 26.1 C 9 in. 7T " 3:68 0.40 0.8 1.20 All rooms: tf-in. pipe or tube; 4-la eoaoete slab. Step 6. Mean Water Temperature - For the required panel output (g)_found in Step 2, the panel resistance (r) found in Step 5, and "the room air temperature (1.), find the mean water temperature (C.) from Fig. 16. Room A B C tw 116.5 109.0 116.5 . ' Step 7. Design Mean Water Temperature ' Select a single design mean water temperature (W.) for each group of rooms which is to comprise a zone, choosing the highest mean water temperature (C.) of the group. In the example, 116.5 F is chosen. __ Step 8. Design Panel Output From Fig. 16 find tbe panel output (9.) for design mean water temperature (4.*), room air temperature ((.), and panel resistance (r,,). Also from Fig. 16 find the design panel surface temperature. If it exceeds 85 F (see Step 3) in a room, go back to Step 5 and choose a wider spacing or smaller pipe or tube for that room. . Room A B C (9-) 25.0 24.0 26.1 4 85.0 (unchanged) 84.5 85.3 (unchanged) Step 9. Design Panel Area Divide the room heat loss found in Step 1 by the design panel output found in Step 8. Room A B C 4, 132 (unchanged) m` 306 (unchanged) ' Step 10- Total Panel Output Add tbe apportioned downward and edgewise beat flow (9<) to the design panel output (?,,) and multiply by the design panel area to obtain the total panel output. If the design panel output is appreciably different from the panel output (g.) used in Steps 3 and 4, tbe apportioned downward and edgewise heat flow fa,) should be redetermined. Room 9- 9a 9. + 9* + 9*) A 25.0* 17.7* 42.7 132 5636 B 24.0 11.6** 35.6 104 3702 C 26.1* 7.1* 33.2 306 10159 * Uactuated. Radetermiaad- Step tl. Fluid Circuit Design the fluid circuit (panel piping and mains) for a tem perature drop of 10 to 20 F deg between the water inlet (4) and outlet (4) of the panel (see Chapter 28, Hot Water Heating Systems). Step It. Boiler Size Select the size of tbe boiler according to method contained in Chapter 35, Heating Boilers, Furnaces, and Space Heaters. The net Btu rating of the boiler should equal or exceed the total output of all panels plus any other loads on the boiler. Procedure for Hot Water Concrete Floor Panels (Intermediate Slab)1' . - The procedure for designing a hot water concrete floor panel of intermediate lab type is given in the following 12 steps. Step l. Heat Loss Follow the procedure for slab-on-grade construction, Step 1. Step t. Required Panel Output Follow the procedure for stab-on-grade construction, Step 2. Step 3. Panel Surface Temperature Follow the procedure for slab-on-grade construction, Step 3. Step 4. Downward Heat Flow Estimate A. Follow the procedure for slab-on-grade construction, Step 4, part 1. B. Estimate the heat flow downward as follows: 1. If the underside of the concrete slab is exposed to form a ceiling, find the heat output downward (as) from Fig. 15, using tbe slab surface temperature (t,) found in Step 3 as the panel surface temperature (4)1 and the air temperature of the space below. 2. If the underside of the concrete slab is not exposed, use the equation: 9- - C.(4 - r) (14) Step 6. Upward and Downward Panel Resistance Follow the procedure for slab-on-grade construction, Step 5, using Table 3 to find both resistances (ru and n,). Step 8. Mean Water Temperature and Downward Heat Flow a. Follow the procedure for slab-on-grade construction, Step 6. - b. Use Fig. 15 to find the downward heat flow (?*). Add to the slab resistance to downward heat flow, (r*), the resistance to heat flow, (rfe), of any material between tbe underside of the slab and the ceiling surface, to find the total resistance to down ward beat flow (r*) to be used in Fig. 15. The water temperature (U) found above and the air temperature (4) of the space below the ceiling are the other two factors to be used. If the beat flow downward (q*) differs appreciably from the estimate made in Step 4, repeat Steps 5 and 6 using the calcu lated value. Step 7. Design Mean Water Temperature Follow the procedure for slab-on-grade construction, Step 7. Step 8. Design Panel Output Follow the procedure for slab-on-grade construction, Step 8. 432 CHAPTER 30 1959 Guide Follow (he procedure for slab-on-grade construction, Step 9. Step 10. Total Panel Output Follow the procedure for slab-on-grade construction, Step 10, substituting heat flow downward (ft) for the apportioned down ward and edgewise heat flow (ft,). Step It. Fluid Circuit Follow the procedure for slab-on-grade construction, Step 11. Step It. Boiler Size Follow the procedure for slab-on-grade construction, Step 12. Installation Details and Accessories The dPKtgn of the two-pipe, direct return forced circulation system which is used in a panel heating system is described generally in Chapter 28, Hot Water Heating Systems. In addition to the usual valves, a balancing valve should be installed in.the supply or return connection of each panel in order to permit the heat output of the panel to be balanced with other panels in the same sone. While all piping should be designed to minimise trapping of air or water, few panel heating systems can be installed to be completely free of air traps. For that reason, panel heating systems cannot usually be filled by flooding nor drained by gravity alone. The system can be filled and the air removed if the system is flushed with a sufficient flow of water. To empty the system a flow of compressed gas is used to assist gravity drainage of the water. Provisions for both flushing and blowing should be included in the piping. De vices for the collection and venting of the gases that will appear during operation should also be provided. Controls . no. ma! mfilt.*faott loads the luQtmvd .eduction in air tem perature is small and, consequently, a conventional room thermostat may be used. In panel heating systems, lowered night temperatures will produce unsatisfactory results with heavy panpla such as concrete floors. These panaia cannot respond to either quick increase or decrease in heating demand within the relatively short time required, with the result that there will be a very slow reduction of space temperature at night and a cor respondingly slow pickup in the morning. Panels of light weight construction, such as plaster or metal filing* and walls, may respond to changes in demand with sufficient rapidity to obtain moderately satisfactory results from lowered night temperatures. However, very little fuel saving can be expected even with tiie light p^npla unless the lowered temperature is maintained for long periods. If reduced non occupancy temperatures are employed, some means of providing a higher-than-normal rate of heat input for rapid warm-up is necessary, or a long warmup period should be provided, as explained in Chapter 28. Warm Air Panels The first three steps in the design of warm air panels are the same as those outlined for warm water panels and the same performance curves can be used. The balance of the design can be determined from the data in the Chapter on Forced Warm Air Systems and Manual 7-A of the National Warm Air Heating and Air Conditioning Association. Electric Panels . Electric panel heating systems ean be designed by using part of the procedure for warm water panels as a guide. See also Chapter 17, Electric Heating. Automatic controls for panel heating differ somewhat Step l. Heat Loss from those described for convective heating because of the Follow the procedure for warm water panels, Step 1. thermal inertia characteristics of the panel heating surface and the increase in the mean radiant temperature within the space under increasing loads for panel heating. However, Step t. Required Panel Output - Follow the procedure for warm water panels, Step 2. many of the control principles for hot water heating systems described in Chapter'28 will also apply to p*nt>1 heating. (See also Chapter 43.) Panels such as concrete slabs have large heat storage Step 5. Panel Surface Temperature Follow the procedure for warm water panels, Step 3. Step 4- Panel Heat Loss capacity and continue to emit heat long after the room thermostat has shut off the supply of heating medium. In addition, there is a considerable time lag between thermostat Determine the heat loss from the panel, using the panel sur face temperature found in Step 3 ana the factors in Chapter 9, Heat Transmission Coefficients of Building Materials. demand and heat delivery to the space due to the large part of the heat which must first be stored in the thermally heavy radiant surface. This inertia will cause uncomfortable varia tions in space conditions unless controls for detecting load changes as early as possible are provided. ' In general, the temperature of the heating medium supplied to tiie panel surface should be varied in accordance with REFERENCES 1 Standard Specifications for Gypsum Plastering, Including Requirements for Lathing and Plastering (American Standards Association, A 42.1, 1946). . . 1 Manual 7A Design and Installation of Warm Air Ceiling Panel Systems (National Warm Air Heating and Air Condi tioning Association). ., outdoor temperature but precautions must be taken to *W. H. McAdams: Chapters 4 and 7 (Heat Transmission, prevent the introduction of excessively hot water which McGraw-Hill Book Co., New York, 1954, 3rd ed.). might damage the panels in the event of control failure. A manual boiler bypass or other means of reducing the water . temperature may be necessary to prevent too rapid drying 4 T. C. Min, L. F. Schutrum, G. V. Parmelee, and J. D. Vouris: ASHAE Research Report No. 1576-- Natural con vection and radiation in a panel heated room (ASHAE Trans actions, Vol. 62, 1956, p. 337). . out of new panels (see section. Embedded Piping for Ceiling * Cyril Tasker, C. M. Humphreys, G. V. Parmelee, and L. F. Panels, in this chapter). - Schutrum: ASHVE Research Report No. 1444--The ASHVE Due to the increase in MRT (mean radiant temperature) Environment Laboratory (ASHVE Transactions, Vol. 58, within a panel-heated space which necessarily takes place os - 1952, p. 139). the heating load increases, the air temperature under such * L. F. Schutrum, G. V. Parmelee, and C. M. Humphreys: ASHVE Research Report No. 1473--Heat exchanges in a conditions, theoretically, should be lowered in the order of 1 ceiling panel heated room (ASHVE Transactions, Vol. 59, or 2 degrees to maintain comfort. In ordinary structures with 1953, p. 197). Panel Heating 433 ? L Schutrum,-G. V. Parmelee, and C. M. Humphreys: ASHVE Research Report- No. 1490--Heat exchanges in a floor panel heated room (ASHVE Transactions, Vol. 59,1953, p. 495). ' L. F. Schutrum and C. M- Humphreys: ASHVE Research Report No. 1499--Effects of non-uniformity and furnishings on panel heating performance (ASHVE Transactions, Vol. 60, 1954, p. 121). L. F. Schutrum and J- D. Vouris: ASHVE Research Re port No. 1516---Effects of room site and non-uniformity of panel temperature on panel performance (ASHVE Trans actions, Vol. 60, 1954, p. 455). it H. H. Macey: Heat loss through a solid floor {Institute of Fuel Journal, 22-128, p. 369). 11E. L. and W. S. Harris: Performance of covered hot water floor panels, Part I--Thermal characteristics (ASHAE Transactions, Vol. 62, 1956, p. 55). u A Subcommittee of the TAC on Panel Heating and Cool ing, R. L. Maher, Chairman; W. P. Chapman; H. T. Gilkey; P B. Gordon; E. F. Snyder; and J. M. Van Nieukerken; and by ASHAE Laboratory Staff Members, L. F. Schutrum and C. M. Humphreys: ASHAE Research Report No. 1600-- Thermal design of warm water concrete floor panels (ASHAE Transactions, Vol. 63, 1957, p. 239). 14 A Subcommittee of the TAC on Panel Heating and Cool ing, R. L. Maher, Chairman; W. P. Chapman; H. T. Gilkey: P. B. Gordon; E. F. Snyder; and J. M. Van Nieukerken: and by ASHAE Laboratory Staff Members, L. F. Schutrum, G. V. Parmelee, and C. M. Humphreys: ASHAE Research Report No. 1559--Thermal' design of warm water ceiling panels (ASHAE Transactions, Vol. 62, 1956, p. 71). BIBLIOGRAPHY B. F. Raber and F. W. Hutchinson: Trend curves for esti mating performance of panel heating systems (ASHVE Trans actions, Vol. 48, 1942, p. 425). - B. F.'Raber and F. W. Hutchinson: ASHVE Research Re port No. 1192--Panel heating and cooling performance studies (ASHVE Transactions,"Vol. 48, 1942, p. 35). F. C. Houghten, Carl Gutberlet, and E. C. Hach: ASHVE Research Report No. 1193--Radiation as a factor in the feel ing of warmth in convection radiator and panel heated rooms (ASHVE Transactions, Vol. 48, 1942, p. 55). - B. F. Raber and F. W. Hutchinson: Panel heating and cool ing, analysis (ASHVE Transactions, Vol. 47, 1941, p. 285). E. J. Rodee: Operating results of a residence radiant wall heating system (ASHVE Transactions, Vol. 47,1941, p.. 123). H. F. Randolph and J. B. Wallace: Performance of a resi dential panel heating system (ASHVE Transactions, Vol. 49, 1943, p. 235). Radiant heating (Heating and Ventilating, March' 1941, p. 35). ^ F. E. Giesecke: Radiant heating and cooling (Heating, Pip ing and Air Conditioning, June, July, August, September and October 1940). . T. N. Adlam: Calculations forradiant heating (Heating and Ventilating, October 1931). -- C. O. Mackay, L. T. Wright. Jr., R. E. Clark, and N. RI Gay: Radiant Heating and Cooling (Cornell University, En gineering Experiment Station Bulletin No. 32, 1943). R. G. Vanderweil: Design method for panel heating systems using copper tubing (ASHVE Journal Section, Heating, Piping ana Air Conditioning, November 1947, p. 123). J. M. Ayres and B. W. Levy: Air temperature gradients in a panel heated room (ASHVE Transactions, Vol. 54, 1948, P- 131). W. P. Chapman and R. E. Fischer: Graphical solution of radiant panel areas (Heating and Ventilating, January 1948, p-88). D. L. Mills and L. J. LaTart: Embedding coils in radiant heating panels (Heating and Ventilating, December 1947, p.75). D. L. Mills and L. J. LaTart: Radiant heat with copper tub ing (Heating and Ventilating, November 1947, p. 95). . D. L. Mills and L. J. LaTart: Panel beat with copper tub ing--experiment in practice (Heating and Ventilating, October 1947, p. 65). B. F. Raber and F. W. Hutchinson: Experimental studies on panel heating tube spacing (aSmve transactions, Voi. 63, 1947, p. 369). S. Konso: Panel heating--a basic discussion (American Artisan, October 1946, p. 68). ' John E. Peterson: Solar house heated by a warm air floor panel (American Artisan, December 1946, p. 83).' A. B. Algren: Design data for a warm air floor panel (Ameri can Artisan, January 1947, p. 141). C. S. Leopold: The mechanism of heat transfer, panel cool ing, heat storage (Refrigerating Engineering, July 1947, p. 33). Radiant Heating--Simplified Design and Installation (Copper and Brass Research Association, 1949). C. M. Humphreys, H. B. Nottage, C. V. Franks, R. G. Huebscher, L. F. Schutrum, and D. W. Locklin: ASHVE Re- search Export No. 1387--Laboratory studies on beat flow within a concrete panel (ASHVE Transactions, Vol. 56, p. 175). ,, L. E. Hulbert, H. B. Nottage, and C- V. Franks: ASHVE Rrannwrer Report No. 1388--Heat flow analysis in panel heat ing or cooling sections (ASHVE Transactions, Vol. 56, 1950, p. 189). C. F. Kayan: Electric an&logger studies on panels with im bedded tubes (ASHVE Transactions, Vol. 56, 1950, p. 205). A. B. Algren: ASHVE Research Report No. 1345--Ground temperature distribution with a floor panel heating system (ASHVE Transactions, Vol. 54, 1948, p. 321). F. W. Hutchinson, D. L. Mills, and L. J. LaTart: Losses from a floor-type panel heating system (ASHVE Trans actions, Vol. 57, 1951, p. 37). C. M. Humphreys, C. V. Franks, and L. F. Schutrum: ASHVE Rerbaroh Report No. 1418--Field studies of beat losses from concrete floor panels (ASHVE Transactions, Vol. 57, 1951, p. 221). . N. S. Billington: Losses from heated floors (Journal of the Institution of Heating and Ventilating Engineers, June 1953). E. L. Sartain and W. S- Harris: Heat flow characteristics of hot water Boor panels (ASHAE Transactions, Vol. 60, 1954, p. 103). ' F. C. Houghten, S. I. Taimuty, Carl Gutberlet, and C. J. Brown: ASHVE Research Report No. 1213--Heat loss through basement walls and floors (ASHVE Transactions, Vol. 48, 1942, p. 369). R. 8- Dill, W. C. Robinson, and H. E. Robinson: Measure ments ofHeat Losses from Slab Floor (National Bureau of Stand- arils, Building Materials and Structures Report BMS 103). H. A. Bareither, A. N. Fleming, and B. E. Alberty: Tempera ture and heat loss characteristics of concrete floors laid on ground (American Artisan, March 1950). N. S. Billington: Heat loss through solid ground floors (Journal of the Institution of Heating and Ventilating Engineers, November 1951). J. R. Jamieson, R. W. Roose, and S. Konso: Warm-air perim eter heating: Part III--Heat losses from floor slab (ASHVE Transactions, Vol. 58, 1952; p. 217). M. Baker, J. M. O'Byrne, and A. M. Levy: Estimating the heat loss from slab floors and basements (Heating, Piping and Air Conditioning, November 1952). N. S. Billington and E. W. Shaw: Experiments with inter mittently operated floor panels (Journal of the Institution of Heating ana Ventilating Engineers, June 1952). N. S. Billington: Heat loss through solid ground floors--II (Journal of the Institution of Heating and Ventilating Engineers, November 1952). ' H. R. Martin, P. R. Achenbach, and R. S. Dill: Effect ofEdge Insulation Upon Temperature and Condensation on ConcreteSlab Floors (National Lure&u of Standards, Building Materials and Structures Report No. 138, October 1953). Aydin Umur, G. V. Parmelee, and L. F. Schutrum: ASHAE RcsBmm Report No. 1528--Measurement of angular emis- sivity (ASHAE Transactions, Vol. 61, 1955, p. 111). C. M. Humphreys, C. V. Franks, and L. F. Schutrum: ASHVE Research Report No. 1426--Laboratory studies of the thermal characteristics of plaster panels (ASHVE Trans actions, Vol. 57,1951, p. 363). L. F. Schutrum and C. M. Humphreys: ASHVE Research . . / 434 CHAPTER 30 1959. Guide Report No. 1491--Further studies of the thermal characteris tics of plaster panels' (ASHVE Transactions, Vol. 59, 1953, p. 511). .- - H. B. Nottage, C.-V. Franks, L. E. Hulbert, and L. F. Schutmm: ASHVE Research Report No. 1492--Heat flow analy sis in panel, heating or cooling sections, case II--Floor slab on earth with uniformly spaced pipes or tubes at the slab-earth interface (ASHVE Transactions, Vol. 59,1953, p. 527). C. M. Humphreys, H. B. Nottage, C. V. Franks, R. G. Hueb- echer, L. F. Schutrum, and D. W. Locklin: ASHVE Research Report No. 1387--Laboratory studies on heat flow, within.a concrete panel (ASHVE Transactions, Vol. 56,'1950, p. .175). - L. F. Schutrum and T. C. Min: ASHAE Research Report No. 1598--Cold wall effects in a. ceiling-panel-heated room (ASHAE Transactions, Vol. 63, 1957, p. 187). . , E. L. S&rtain and W. S. Harris: Performance of covered hot water floor panels, Part II--Room conditions (ASHAE Trans actions. Vol. 63, 1957, p. 209). ' CHAPTER 31 pipe; fittings, welding Pipe Materials, Types of Pipe, Commercial Pipe Dimensions, Threading Practice, Pipe Fittings, flange facings and Gaskets, Valves, Welding. Expansion and Flexibility, Hangers and Supports IMPORTANT considerations in the selection and installa tion of pipe and fittings for heating, ventilating, and air conditioning are dealt with in this chapter. PIPE MATERIALS Use of corrosion-resistant materials for pipe, including special alloy steels, copper, and red brass, has increased considerably during the past few years. The following brief discussion indicates the variety of pipe materials and the types of pipe available. Wrought-Steel Pipe. Because of its lower cost, the great bulk of wrought pipe used for heating and ventilating work at the present time is of wrought steel. The material used for steel pipe is a mild steel made by the acid-bessemer, the open-hearth, or the electric-furnace process. Ordinary wrought-steel pipe is made either by shaping sheets of metal into cylindrical form and welding the edges together, or by forming or drawing from a solid billet. The former is known as tedded pipe, the latter as seamless pipe. Many types of welded pipe are available, although the smaller sizes most frequently used in beating and ventilating work are made by the lap-weld, resistance-weld, or butt weld process. While the lap-weld and resistance-weld proc esses produce a better weld than the butt type, lap-weldand resistance-weld pipe are seldom manufactured in nominal pipe sizes less than 2 in. Seamless pipe can be obtained in the small sizes at a somewhat higher cost, and is listed as pres sure tubing below 2 in. Seamless steel pipe is frequently used for high-pressure work or where pipe is desired for close coiling, cold bending, or other severe forming operations. Its advantages are its greater strength which permits use of a thinner wail and, in the small sizes, its freedom from the occasional tendency of welded pipe to split at the weld when bent. Wrought-iron Pipe. Wrought-iron pipe may be identified by the spiral line marked into each length, either knurled into the metal or painted on it in red or other bright color. Otherwise, there is little difference in the appearance of wrought-iron and steel pipe, although microscopic examina tion of polished and etched specimens will readily riisrlwa different grain structures. Cast-Ferrous Pipe. There are now available several types of cast-ferrous metal pipe made of a good grade of castiron with or without additions of nickel, chromium, or other alloy. This pipe is available in rises from Wi in. to 6 in., and in standard lengths of 5 or 6 ft, with external and internal diameters closely approximating those of extra strong wrought pipe. Cast-ferrous pipe may be obtained coupled, beveled for welding, of with ends plain or grooved for the several types of couplings. It is earily cut and threaded as well as welded. The fact that it is readily welded enables the manufacturers to supply the pipe in any lengths practicable for handling. AUoy Metal Pipe. Both iron and steel pipe are available in the alloy class. In the ease of iron pipe when copper and molybdenum are added, the material is known as alloy wrought-iron pipe. By common custom steel is considered to be an alloy when the maximum range of alloying elements exceed certain limits such as 1.65 percent manganese, 0.60 silicon, or 0.60 copper. Also, a steel is an alloy if any of the following ele ments are'specified in minimal quantities or within limits: Al, B, Cr (up to 3.99), Co, Cb, Mo, Ni, Ti, W, V, Zr, or any other element added to obtain a certain alloying effect. Small quantities of certain elements are present in alloy steels and are considered as incidental.and may be present to the following maximum amounts: copper--0.35 percent, nickel--0.25 percent, chromium--020 percent, and molyb denum--0.06 percent. . Commercially, steel is considered stainless when chromium exceeds 3.99 percent regardless of the inclusion of other al loying elements. With tubing, however, an alloy becomes stainless when it contains a minimum of 10.5 percent chro mium. ' The alloy and stainless steels are used for high tempera ture piping and for highly corrosive fluids and gases. Copper'Pipe and Fittings. Owing to inherent resistance to corrosion, copper and red brass pipe have always been used in beating, ventilating, and water supply installations, but the cost with standard dimensions for threaded connections has been high. The introduction of fittings which permit erec tion by soldering or sweating, allows the use of tube with thinner walls than would be possible with threaded con nections, thereby reducing the cost of installations. COMMERCIAL PIPE DIMENSIONS Commercial pipe dimensions are covered in the following specifications of the American Society for Testing Materials: (1) steel--AHTM A-120 and A-53, (2) wrought iron--ASTM A-72, and (3) copper tube--ASTM A-88. Tables 1 and 2 are based on these specifications. In addition to the specifications for these three materials, there are standards for copper or red brass IPS, clay or con crete, and cast-iron pipe. Copies of the following specifica tions may be obtained from the American Society for Testing Materials: (1) steel, wrought-iron, and cast-iron--Series A, (2) copper and red brass--Series B, and (3) clay and con crete--Series C. Table 3 lists the sizes available in each of the specifications and classes of steel pipe. Note that butt-weld is not available above 4-in. rise and that lap-weld, electric-reristance-weld, and seamless are not available below 2-in. sue. 435 436 CHAPTER 31 1959 Guide Nominal* ASTMb Sir* Sdwdnfe K 40 (s) 80 (x) K' 40 (s) 80 (x) H 4 () 80 (x) H 40 w 80 (x) XX H 40 (.) 80 (x) XX 1 40 (s) 80 (x) XX IK 40 (s) 80 (x) XX IK 40 (e) 80 (x) XX 2 40 (a) 8X0X(x) m 40 (s) 80 (x) XX 3 40 (s) 80 (x) 3K 40(a) 80 (x) XX 4 40 (s) 80 (x) XX 5 40 (s) 80 (x) XX . 6 40 (b) 80 (x) XX 8 30 (s) 40(b) 80jx) 10 (8) 30 (s) 40 (s) 60 (x) 12 30 (a) (8) W. 14 .30 (s) <x) Oieaaiar OO ID fa. In. Table !.... OiuicfsicM cr.d Properties of Steel Pipe Wall Surface Area Sq Ft/lia Ft Section Ana Sq fa. Areo'of In. OO (D OO CD Sq fa. Gcd/lfa Ft 0.405 0.269 0.405 0.215 .0.068 0.095 0.106 0.0704 ' 0.129 0.106 0.0563 0.129 0.0568 0.0363 0.0720 0.00295 0.0925 ` 0.00189 Weight* (plain and) Lb/Un Ft 0.244 0.314 Working Pitaof4 Pbo 314 (a) 1084 (a) 0.540 0.364 0-540 0.302 0.088 0.119 0.141 0.0953 0.141 0.0791 0.229 0.229 0.104 0.0716 0.125 0.157 0.00541 0.00372 0.424 649 (a) 0.535 1353 (a) 0.675 0.493 0.675 0.423 0.091 0.126 0.177 0.129 0.177 0.111 0.358 0.358 0.191 0.140 0.167 0.217 0.00992 0.00730 0.567 574 (a) 0.738 1191 (a) 0.840 0.840 0.840 0.622 0.546 0.252 0.109 0.147 ' 0.294 0.220 0.220 0.220 0.163 0.143 0.0660 0.554 0.554 0.554 0.304 0.234 0.0499 0.250 0.320 0.504 0.0158 0-0122 0.00259 0.850 1.09 1.71 697 (a) 1266 (a) 3824 (a) 1.050 1.050 1.050 0.824 0.742 0.434 0.113 0.154 0.308 0.275 0.275 0.275 0.216 0.194 0.114 0.886 0.866 0.866 0.533 0.432 0.148 0.333 0.434 0.718 0.0277 0.0225 0.0076S 1.13 1.47 2.44 604 (a) 1078 (a) 3134 (a) 1.315 1.315 1.315 1.660 1.660 1.660 1.049 0.957 0.599 1.380 1.278 0.896 0.133 0.179 0.358 0.140 0.191 0.3S2 0.344 0.344 0 344 0.275 0.251 0.157 0.435 0.435 0.435 0.361 0.335 0.235 1.36 1.36 1.36 2.16 2.16 2.16 0.864 0.719 0.282 1.50' 1.28 0.630 0.494 0.639 1.08 0.669 0.881 1.53 0.0449 0.0374 0.0146 0.0777 0.0666 0.0328 1.68 2.17 3.66 ' 2.27 3.00 5.21 651 (a) 1083 (a) 2963 (a) 440 (a) 805 (a) 2318 (a) 1.900 1.900 1.900 1.610 1.500 1.100 0.145 0.200 0.400 0.497 0-497 0.497 0.421 0.393 0.288 2.84 2.84 2.84 2.04 1.77 0.950 0.800 1.07 1.89 0.1058 0.0918 0.0494 2.72 3.65 6.41 417. (a) 756 (a) 2122 (a) 2.375 2.375 2.375 2.067 1.939 1.503 0.154 0.218 0.430 0.622 0.622 0.622 0.541 0.508 0.393 4.43 4.43 4.43 3.36 2.95 1.77 1.07 1.48 2.66 0.174 0.153 0.0922 3.65 5.02 9.03 376 (a) 690 (a) 1861 (a). 2.875 2.875 2.875 3.500 3.500 3.500 2.469 2.323 1.771 3.068 2.900 2.300 0.203 0.276 0.552 0.216 0.300 0.600 0.753 0.753 0.753 0.646 o:eo8 0.364 0.916 0.916 0.916 0.803 0:759 0.602 6.49 6.49 6.49 9.62 9.62 9.62 4.79 4.24 2.46 7.39 6.61 4.15 1.70 2.25 4.03 2.23 3-02 5.47 0.249 0-220 0.128 0.384 0.343 0.216 5.79 7.66 13.7 7.57 ' 10.3 18.5 505 (a) 806 (a) 2048 (a) 454 (a) 734 (a) 1829 (a) 4.000 4.000 4.000 3.548 3.364 2.728 0.226 0.318 0.636 1.05 1.05 1.05 0.929 0.881 0.714 12.6 12.6 12:6 9.89 8.89 5.85 2.68 3.68 6.72 0.514 0.462 0.304 9.11 12.5 22.9 425 (a) 692 (a) 1699 (a) 4.500 4.500 4.500 4.026 3.826 3.152 0.237 0-337 0.674 1.18 1.18 1.18 1.05 1.00. 0.825 15.9 15.9 15.9 12.7 11.5 7.80 ' 3.17 4.41 8.10 0.661 0.597 0.405 10.8 14.9 27.5 403 (a) 663 (a) 1602 (a) 5.563 5.563 5.563 5.047 4.813 4.063 0.258 0.375 0.750 1.46 1.46 1.46 1.32 1.26 1.06 24.3 24.3 24.3 20.0 18.2 13.Q 4.30 6.11 11.3 1.04 0.945 0.673 14.6 20.8 38.6 498 (b) 825 (b) 1951 (b) 6.625 6.625 6.625 6.065 5.761 4.897 0.280 0.432 0.864 1.73 1.73 1.73 1.59 1.51 1.28 34.5 34.5 34.5 28.9 28.1 18.8 5.58 8.40 15.6 1.50 1.35 0.978 18.0 28.6 53.1 467 (b) 825 (b). 1912 (b) 8.625 8.625 8.625 8.625 8.071 7.981 7.625 6.875 10.750 10.750 10.750 10.750 10.192 10.136 10.020 9.750 0.277 0.322 0.500 0.875 0.279 0.307 0.365 0.600. 2.26 2.26 2.26 2.26 2.11 2.09 2.00 1.80 2.81 ' 2.81 2.81 2.81 2.67 2.65 2.62 2.55 58.4 58.4 58.4 58.4 90.8 90.8 90.8 90.8 . 51.2 50.0 45.7 37.1 81.6 80.7 78.9 74.7 7.26 8.40 12.8 21.3 9.18 10.1 11.9 16.1 2.66 2.60 2.37 1.93 4.24 4.19 4.10 3.88 ' 24.7 28.6 43.4 72.4 31.2 34.2 40.5 54.7 351 (bj 431 (b) 753 (b) 1460 (b) 285 (b) 324 (b) 405 (b) 600 (b) 12.750 12.090 12.750 12.000 12.750 11.750 0.330 0-375 0.500 3.34 3.34 3.34 3.17 3.14 3.08 128. 128. 128. 115. 113. 108. 12.9 14.6 19.2 5.96 5.88 5.63 43.8 49.6. 654 299 (bj 352 (b) 503 (b) 14.000 13-250 14.000 13.000 0.375 0.500 3.67 3.67 3.46 3.15 154. 154. 138. . 133. 16.0 21.2 7.17 6.70 54.6 72.1 458 (c) 653 (c) ? Pipe, fittings, Welding 437 Nominof* Sir* ASTM* Schedule 40 (x) (x) 30 (e) (s) Table 1 .... Dimensions and Properties of Steel Pipe (Concluded) Diameter OD ID fa. fa. Wall Tfcidcnez* fa. Surface Area Sq Ft/Un Ft OD ID Section Area Sq fa. OD ID Motel Sq In. Volume Gd/UnFt 16.000 15.250 16.000 15.000 0.375 0.500 4.18 4.18 3.99 3.93 201201. 183. 177. 18.4 24.3 9.48 9.18 18.000 17.250 18.000 17.000 0.375 0.500 4.71 4.71 4.52 4.45 254. 254. 234. 227. 20-7 27.4 12.1 11.8 20.000 19.250 20.000 19.000 0.375 0.500 5.23 5.23 4.51 4.97 314. 314. 291. 284. 23.2 30.6 152 14.7 24.000 23.250 24.000 23.000 0.375 0.500 6.29 6.29 6.08 6.03 452. 452. 426415. 26.8 36.9 22.1 21.5 Weight* (placn end) Lb/Lin FI 624 82.8 70.6 93.5 78.6 104.2. 94.6 125.5 Working Protean* Fao 400 (c) 570 (c) 355 <c) 506 (c) 319 (c) 454 (c) 265 to) 378 (c) * 8H double extea etrooi b looter considered in ASTU specification but aone pipe o this site b still manufactured. yhe ti-- for wrought iron ere approximately tbs same except well thickness b slightly heavier. See ASTU A-7J. b XflMnma ffrrffir far Tcstuic UeUriaU Schedule. The numbers JO, 40, etc., refer to the ASTU Schedule; the letter (a) refers to the former designation Standard IPewit; Um letter (x) refers to tbe former tViiinstion Extra Strong', the letters XX refer to the farmer dseifnatioa DaabU Extra Strong. * Wei*bt per foot b based on plain end pipe. Threaded and coupled <T and pipe b slightly heavier. ' * Working presto* for welded joints see formula in Table 3. (1) Working pressure bssed on an allowable fiber stress of 6J25 psi (for 390 F). (3) Winking pressure based on an allowable fiber stress of MOO psi (for 350 F). (3) Working pressure bssed os an allowable fiber stress of U000 psi (for 3S0 F). Note: Standard-weight pipe b generally famished with threaded ends in random lengths oflfi to S3 ft., although when ordered with plain ends, 9 percent may be in of 13 to 19 ft Five percent of tbs total number of lengths ordered may he jointers which are two pieces coupled together. Extra-etrong pipe b generally fur- with pt-ln ends in random lengths of 12 to 33 ft, although 9 percent may be in lengths of 0 to IS ft listed in Table 3 is the formula for allowable working pressures as given in the American Standard Code for Pres sure Piping* In this formula is a factor c, which is intended as an allowance for corrosion, mechanical injury, manufac turing tolerances, etc. At times this factor seems too con servative; for example, with Ys-in., Schedule 40, steel pipe, the allowable working pressure is 314 pm. Yet this pipe is tested at 700 psi. The reasoning in establishing the factor c which influences the working pressure, is that after nominal use the pipe may not be as sturdy as it was at the time of manufacture. Note that the joint factor, c, is not included for plain end non-ferrous pipe as listed in Table 2. In addition to IPS copper pipe, several varieties of copper tubing are in use with either flared or compression couplings or soldered joints. Dimensions of copper water tube intended for plumbing, underground water service, fuel-oil lines, gas lines, etc., have been standardized by the G. S. Government and the American Society for Testing Materials. Copper tube is classified in accordance with the wall thick- nes as follows: Type K--Heavy Wall. . Type L--Medium Wall.. . Type M--Light Wall. Type DWV--Light Wall--for drainage, waste, and vent service. In general, Type K is used for underground services and for general plumbing service where corrosion conditions are severe. Type L is used for general plumbing and-heating service where conditions may be considered normal. Type M is used for sanitary drainage and other non-pressure ap plications, for heating, and sometimes for other services less severe than those for which Types K or L are recommended. Type DWV is of lighter weight than Type M, and is used for sanitary drainage and other non-pressure applications. Type DWV tube should not be used underground. Type L is suitable for underground drainage applications. Unless adequately protected, no copper tube should be embedded in a cinder fill. Where flexibility is essentia! as in hidden, re placement work, or where as few joints as possible are de sired as in fuel-oil lines, the soft temper is commonly used. In new or exposed work copper tube of a hard temper is generally used. All three types are extensively used with soldered fittings. Standard dimensions, weights, and diameter and wall- thickness tolerances for these nlflssfis of copper tube are ob tainable from Table 2. Copper pipe is also available with dimensions of steel pipe. In refrigeration lines, used in connection with air-condi tioning equipment, copper tube is used extensively. For re frigeration use where tube absolutely free from scale and dirt is required, bright annealed copper tube that has been cleaned, dehydrated, and sealed is used. This tube is avail able in a variety of sizes and wall thicknesses. THREADING PRACTICE In all threaded pipe for heating and ventilating installa tions the American Standard taper pipe thread, ASA B2.11945 is used. This thread is cut with a taper of 1 in 16 measured on the diameter of the pipe so as to secure a tight joint. The number of threads per inch varies with the pipe size. Threads for fittings are the same, except that it is regular practice to furnish straight tapped couplings for Schedule 40 pipe 2 in. and smaller. For steam pressures in excess of 25 psi, it is recommended that taper-tapped couplings be used to obtain a tight joint. These may be secured by ordering line pipe* which is used for oil piping, the .couplings of which are provided with taper-tapped threads and may be used with regular mill-threaded standard weight pipe. Thread lengths should be in accordance with ASA B2.1. Right-hand threads are used unless otherwise ordered. To facilitate drainage, some elbows have tbe thread tapped at an angle to provide a pitch of the connecting pipe of Y* in. to the foot. These elbows are known to the trade as 438 CHAPTER 31 1959 Guide Table 2 .... Dimensions and Properties of Copper Tube (AH Typer Except DWV on bated ea ASTM Mt) Noafaaf Site Type Otamefer OD U> In. tn. Waff Throbne** In. Surface Aiwa SqH/Unft OD ID Section Area Sq fa OD ID Mmtul ' Sq fa Voktme Weight* Gal/tie ft lb/ UaFt WoHunp Pda X X X X X 1 m IK 2 2K 3 3M 4 5 6 -8 10 12 K 0.375 0.305 L* 0.375 0.315 K 0.500 0.402 L 0.500 .0.430 K 0.625 0.527 L 0.625. .0.545 K 0.750 0.652 L 0.750 0.666 E 0.875 0.745 L 0.875 0.785 K 1.125 0.095 L 1.125 1.025 K L M DWV 1.375 1.375 1.375 1.375 1.245 1.265 1.291 1.295 K L. M DWV 1.625 1.625 1.625 1.625 1.481 1.505 1.627 1.541 KL M DWV 2.125 2.125 2.125 2.125 1.050 1.985 2.009 2.041 K 2.625 2.435 L 2.625 2.465 M 2.625. 2.495 K L M DWV 3125 3.125 3.125 3.125 2.907 2.945 2.981 3.035 K 3 625 3.385 L 3.625 3.425 M 3.625 3.459 K L M DWV 4.125 4-125 4.125 4.125 3.857 3.905 3.935 4.009 K 6.125 4.805 L 5.125 4.875 M 5.125 4.907 K L M DWV ,6.225 6.125 6.125 6.125 5.741 5.845 5.881 5.959 K 8.125 7.583 L 8.125 7.725 M 8.125 7.785 K 10125 9.449 L 10.125 9.625 M 10-125 9.701 K 12.125 11.315 L 12.125 11.565 M 12.125 11.617 0.035 0.030 0.0982 0.0798 0.0982 0.0825 0.110 0.110 0.0730 0.0779 0.0374 0.0324 0.049 0.035 0.131 0.131 0.105 0.113 0.196 0.196 0.127 0.145 0.0695 0.0512 0.049 0.040 0.164 0.138 0.164 0.143 0.306 0.306 0.218 0.233 0.0887 0.0735 0.049 0.042 0.193 0.171 0.193 0.174 0.441 0.441 0.334 0.348 0.108 0.0934 0.065 0.045 0.229 0.195 0.229 0.206 0.601 0.601 0.436 0.480 0.165 0.117 0.065 0.050 0.295 0.260 0.295 0.268 0.994 0.994 O.T78 0.852 0.216 0.169 0.065 0.055 0.042 0.040 0.360 0.360 0.360 0.360 0.328 0.331 0.338 0.339 1.48 1.48 1.4S 1.48 1.22 1.26 1.31 1.32 0.268 0.228 0.176 0.163 0.072 0.060 0.049 0.042 0.425 0.425. 0.425 0.425 0.388 0.394 0.400 0.403 2.07 2.07 2.07 2.07 1.72 1.78 1.83 1.86 0.351 0.295 0.243 0.205 0.083 0.070 0.058 0.042 0-556 0.556 0.556 0.556 0.513 0.520 0.526 0.534 3.56. 3.56 3.56 3.56 3.01 3.10 3.17 3.27 0.532 0.452 0.377 0.288 0.095 0.080 0.065 0.687 0.687 0.687 0.638 0.645 0.653 5.41 5.41 5.41 .4.66' 4.77 4.89 0.755 0.640 0.523 0.109 0.090 0.072 0.045 0.818 0.818 0.818 0.818 0.761 0.771 0.780 0.796 7.67 7.67 7.67 7.67 6.64 1.03 6.81 0.858 6.98 ' 0.691 7.23 0.435 0.120 0.100 0.083 0.949 0.949 0.949 0.886 0.897 0.906 10.3 10.3 10.3 9.00 9.21 9.40 1.32 111 0.924 0.134 0.110 0.095 0.058 1.08 1.08 1.08 1.08 1.01 1.02 1.03 1.05 13.3 13.3 13.3 13.3 11.7 12.0 12.2 12.6 , 1.68 1.39 1.20 0.67 0.160 - 1.34 0.125 1.34 0.109 1.34 1.26 1.28 1.29 20.7 20.7 20.7 18.1 18.7 18.9 2.50 1.96 ' 1.72 0.192 0.140 0.122 0.083 1.60 1.60 1.60 1.60 1.50 1-53 1.54 1.56 29.4 29.4 29.4 29.4 25.9 26.8 27.2 27.9 3.50 2.63 2.30 1.58 0.271 0.200 . 0.170 2.13 2.13 2.13 1.99 2.02 2.04 51.8 5K8 51.8 45.2 46.9 47.6 6.69 4.98 4.25 0.338 0.250 0.212 2.65 2.65 2.65 2.47 2.52 2.54 70.5 80.5 80.5 70.1 72.8 73.9 10.4 7.76 6.60 0.405 0.280 0.254 3.17 3.17 3.17 2.96 3.03 3.04 115. 115. 115. ' 101. 105. 106. 14.9 10.4 9.47 0.00379 0.00404 0.00660 0.00753 0.0113 00121 0.0174 0.0181 0 0227 0.0250 0.0405 0.0442 0.0634 0.0655 0.0681 0.0684 0.0894 0.0925 0.0950 0.0969 0.157 0.161 0.164 0.142 0-242 0.247 0.254 0.345 0 354 0.362 0.376 0.468. 0.478 0.489 0 607 0.623 0 634 0.656 0.940 0.971 0.981 1.35 1.39 1.42 1.55 2.34 2.43 2.47 3.65 3.79 3.84 6.24 5.45 5.50 0.145 0.126 0-269 .0.198 0.344 0.285 . 0.418 0.362 0.641 0.455 0.839 0.655 1.04 0.884 0.682 0.650 1.36 1.14 0.940 0.809 2.06 1.75 1.46 1.07 2.93 2.48 2:03 4.00 3.33 2.68 1.69 5.12 4.29 3.58 6.51 5.38 4.66 2.87 9.67 7.61 6.66 13.9 10.2 8.92 6.10 25.9 19.3 16.5 40.3 30.1 25.6 57.8 40.4 36.7 918 764 988 677 779 625 . 643 547 - 747 497 574 432 466 387 293 421 359 289 376 316 255 352 295 234 343 278 220 324 268 218 135 256 217 307 234 203 308 221 330 . 239 200 332 241 202 334 225 204 Pipe, Rttings,. Welding . ' .'Notes for Table 2 Weight per foot a baaed on tube without oouplmge. ' k Working pmsure b baaed on the Aetericon Standard CadtferPrttnsn Pipiag, published by tht A.SMB, reined November, 1953 for {data end tubing (sweat joints). '' P __JSs_ D - 0-B. - wlcra P -- allowable pressure, pound* per square inch. g*ge- * - prn poi allowable fiber streaa, pounds per square inch. -- minimum wall tk"-t --, inches. . .. 2) Ifnrininin OD, inches. . * Types K and L lomisbed in both bard and *oft tempos. Type M in bard oaly. Standard straight length* are JO H. Standard coils 04 to 1)4 inch) are 60 ft. ________ Table 3 .... Table of Availability for Steel Pipe Material Spocfficofioo Avetkdde Sum (fodoncl facte* Ota Affowobte Fiber Sfreo S* pa Lap-weld Electric-resistance Seamless A-120 A-53 A-120 A-53 A-53 Grade A A-53 Grade B A-53 Grade A A-53 Grade B A-120 X to 4 X to 4 2 to 12 2 to 24 2 59 24 2 to 24 2 to 24 2 to 24 2 to 12 6,225 6,750 8,400 9,000 10,200* 12,760b 12,000 15,000 10,400 5 -- fibestress, pounds per square inch. 1* - 0.ST5 a wall thfeknea. iocfaea. D - OD, inches. ------ c joint factor 0.05 for 1-in. and --aiaeor 0X65for larger than 1-in. eise. See American Standard Cede for Pretten Piping, published by ASME, re vised November, 1952. . b For electric reestanee welded pipe far application* where the temperature is below 650 F, and where pipe formated under thb classification b subjected to supplemental tests and/or best treatments a* agreed to by the supplier and the purchaser, snd whereby such supplemental tests and/or best treatments demon strate the strength'etermetenstka of the weld to be equal to the minimum tensile strength apawfiad for the pipe, tte 8 values equal to the cMmumiuting scamtea grades rosy be used. ' pitch elbows and are commercially available. All threaded pipe joints should be made up with a thread paste suitable for the service for which the pipe is to be used., Table 4 contains pertinent threading data for standard weight, extra strong and double extra strong steel, and wrought-iron pipe. The normal engagement of pipe threads is given in Table 5. - ' PIPE RTTINGS Pipe is joined by butt welding one length to another or by the use of fittings. Pipe fittings are made in a variety of forms (the common types are listed in Table 6), and are screwed, flanged, or welded. The type of fitting to be used is determined by the pressure of the fluid being carried, or by the intended use of the pipe line. The materials generally used are steel, cast iron, malleable iron (heat treated cast iron), copper, brass, stainless steel, alloy steel, or bronze. The material used also depends upon the pressure or character istics of the fluid. fittings are designated and sized in accordance with Ameri can Standards Association specifications and are identified by their nominal pipe sizes. ' . In the case of reducing tees, crosses, and Y-branches (lat erals), the size of the largest run opening is given first, fol- 439 Toble 4 . Threading Data for Pipe Standard Weight Nominal Six* Pipe OD Thread* Coup pertndi* ling OD Coup-. Dng Length Extra and Double Extra Strong Coupling OD ling length X 0.405 27 X 0.540 18 X 0.675 18 X 0.840 14 H 1.050 14 0.563 0.719 0.875 1.063 1.313 'Hi IK. 1K IHe IK 27 18 18 14 14 0.563 0.719 0.875 1.063 1.313 IHe IK IK K 2K l 1.315 UK 1.576 2 UK 1.576 2K IK 1.660 nx 1.900 2Ke 11K 2.054 2X IX 1.990 UK 2.200 2He UK 2.200 2K 2 2.375 liK 2.750 2K UK 2.875 2K 2X 2.875 8 3.250 3K 8 3.375 4K 3 3K .4 5" 6 3.500 4.000 4.500 5.563* 6.625 8 8 8 8 8 8 8.625 --10 10.750 --12 12.750 --14 14.000 16 16.000 -- _18 18.000 20 20.000 -- 4.000 4.625 5.000 6.296 7.390 _-- ` ---- - _ -- 3K 3X 3K 3K 4 _ -- -- -- - _ -- 8 4.000 4K 8 4.625 4K 8 5.200 4H 8 6.296 4K 8 7.390 4K 8 9.625 5H 8 11.750 5K 8 14.000 *K 8 15.000 6K 8 17.000 W 8 19.000 7X 8 21.000 7K b Taper of thread* i* X in. per ft on diameteron all (nee of pipe, end in cou plings of 1H in- sod over- Coupling* 1 in. sad smeller ere Mreight topped. * 5X63 for copper and red hr*** pipe. Note: Tte well thiekneee end inside dismeter ebown in Table 1 do not e^ply to Table 5 .... Normal Engagement of Tight-Rt Mate and Female Pipe Threads For American Standard end API Pipe Thread* Pipe Sixet Engaged length* la Pipe Sixet Engaged length In. XX 2K XX 3 XX 3X K K -4 K K. 5 l K. 6 IK . lXs - 8 IK 10 2 X 12 K. 1 1K IK IK IKe 1K IK IK Diatenekm atewn is tbe tight-fit thread engagement from the feed ing edge of the female thread beck to the feiriing edge of tbe male thread. No eUawenee tea been n--** far threading venations. ' lowed by the size of the opening at the opposite end.of the run. Where the fitting is a tee or Y-branch (lateral), the size of the outlet is given last. Where the fitting is a cros, the largest rideTOutlet opening is the third dimension given followed by tbe opening opposite. The straight line sketches, Fig. 1, illustrate how the reducing fittings are designated. Where an external thread is wanted the word male follows the size of that opening. 440 CHAPTER 31 . - 1959*Guide Table 6 ..... ripe Firings 90. 60. 45 A 22V4* Standard 90 A 45* Street 90 A 45* Male union 90 A 45* Female union 90 A 45" Butt-welding 90 A 45* Socket-welding 90 A 45* Flanged 90* Side outlet 90* Railing 90* Side outlet railing Base Drop Tebs Standard Flanged Female union Flanged base Railing Service Flanged side outlet Female union outlet Butt-welding Side outlet railing Four-way Male union Flanged reducing Socket-welding Drop Coupu NOS Wrought Cast Socket-welding Cbossbs . Screwed Flanged Butt-welding Y-Bends 45* Screwed 45* Flanged 45* Double screwed True flanged Retubn Bends Butt-welding Back outlet Screwed Union end Reducers Standard Eccentric soeket- welding Flanged paper Flanged ecbut-welding centric Bushings Outside hexagon Eccentric. Face Caps Standard Socket-welding Butt-welding Plugs Countersunk Square-head Bar Nipples Close ' Long Tank Unions Female Bushings Outside Male A female Flange . Eccentric Tongue A groove flange- Face ' Caps ' Standard Socket-welding Butt-welding Plugs Countersunk Square head Bar Nipples Close Long . Taok Unions - - Female Male A female Flange Tongue A groove . flange Flanges Blind Floor ' Screwed Slip-on Welding neck Reducing Allowable pressures for solder-type fittings are given in Table 7. Allowable pressures for ferrous screwed, flanged, and welding fittings according to ASA specifications are given in Table 8. Steel welding (butt or socket type) fittings may be used for the same pressure as the pipe, providing wall thiplmpgq (or schedule number), and also the material, are the same as the pipe on which they are used. Screwed fittings include: couplings, elbows (45* or 90*), return bends (close and open), tees, crosses, laterals (Y- branches), plugs, caps, lock nuts, flanges, bushings, and re ducing fittings (elbows, tees, and couplings). Reducing fittings and bushings may be eccentrically tapped to permit drainage of condensate. Sometimes nipples are erroneously called fittings. Actually a nipple is a piece of pipe less than 12 in. long that has been threaded on both ends. Pipe 12 in. or longer is regarded as cut pipe. Nipples are classified as dose or full thread, shoulder, short, and long. A close nipple is about twice the length of looie / .... Service Presswie Ratings for V/roughf-Copper or Bronze Solder Joint fittings* .. Typo of SoUor Maximum Strnc* Prenwre, Pag Service Woter Temp^ F to 1a5T 1 ln.b 2 In.6 2Ib> ( 50-50 Tin-lead (ASTM B32 Alloy Grade 50A) .( 100 150 200 250 200 175* ISO6 150 125* 1004 100 90* 754 85 75* 604 _ -- 15* 95-5 Tin-antimony or 95-5 Lead-tin (ASTM B32| Alloy Grade 5A) 1 100 150 200 250 500 400 400 350 300 250 200 175 300 275 200 150 15 Solders with melting point 1100 F or above 350 270 190 155 120 Note: Retincs other then specified here tasy be axed upon the recommeads- Uoo of the manufacturer aa to the proper adders that should be used. `Extracted tram American Standard far Wroufil Copper end Bronx* Solder Joitd FiOintt, B15.*3-1851. - b Standard water tube sues except 1-8 in., which a H in. OD imtmlrii copper tubing for refrigerator set-rice, etc- (ASTM B68). * These pressures may be used for cast-brass fittings (Add B16.1S-18S0) for sites 3 in. and smaller. 4 These pressures may be used for east-braes fittings (ASA BIS.15-1850) for sixes 2H itL and above. Also allowable for cast-brass fiUinfs (ABA B16.15-1850). the pipe thread since the threads actually meet. A shoulder nipple has a shoulder between , the threads and is further clarified as zAort or long. All shoulder nipples are cut to specific lengths and sold in that manner. As a general, rule, flanged joints are used when it is ex pected that the line will be disassembled quite often. There are three types of joints for attaching the flange to the pipe; screwed, welded, or lapped. Types of contact surface will be discussed in the next section. . Tables 9 to 15 give data on various types of ferrous fittings. . Fittings for copper tubing are available in soldered, flared, or compression types (see Figure 2). Fittings for copper pipe of IPS dimensions are available in screwed or soldered types. Table 16 gives size data for screwed fittings and Tables 17 and 18 give data for solder-type fittings for copper tube and pipe. ' 4x4X2 TEE *- h 4(8x2 TEE T-4BxR4A>N2CH \ 40x2 -BRANCH 4*4 *2*2 CROSS 4*40x2 CROSS . CROSS fig. 1.... Description of Tees and laterals (ASA B16.3--19511 * Pipe, Fittings, Welding 441 Table 8____ ASA Specifications and Pressures for . . Ferrous Screwed, Flanged, and Welded fittings . . -' Type of Fitting Specification Steam . Preoxrre Po'g* Tab!e-.9 ;.. . Dimensions of Screwed Cost-Ire** 90* . and 45-Deg Elbows, Tees; and Crosses (Gass 125) ` - ' (Straight Sizsx) ' B16.1 B16b Cast Iron--Flanged (refrigeration)... B16.16 B16.4 B16.3 - 300' B16.5 2500 * Pressure may reduce with increasing rizas. This pressure is the maximum allowed in this specification forsaturated steam. Higher pressuresmay be allowed with lower temperatures. `. The compression-type fitting is generally limited to small sizes of tube, while the flared and soldered types are used in both large and small sizes. An American Standard, ASA A40.2 (1936), has been prepared to standardize dimensions of brass fittings for flared copper tube. Flared tube fittings are widely used in refrigeration work where SAC dimensions and a 45-deg flare render most fittings interchangeable, al though for refrigeration use, thread fits and tolerances on thread gages must be maintained within close limits. Brass, fittings with SAC dimensions are not interchangeable with the American Standard fittings for water tube. . FLANGE FACINGS AND GASKETS There are many types of flange facings. The simplest, and the one most commonly used, is the plain face. This type of ' face is used with fittings shown in Table 10. Other facings,` with varying complexity/are used for higher pressures. They include: male and female face (an insert type face), tongue- and-groove (an adaptation of the male and female type), lapped pipe to flange, lapped pipe to pipe, and ring and groove using neck flanges.. . As it is too expensive to machine flange faces sufficiently to provide watertight joints, a gasket is usually inserted be- _L -- T e* MX ELM. . Nooj- Pip Size fo End, Shows, Tees, Center to End, 45Dog Shows length , of Thread, Min fluid* Oiameter Width . of fitting . of Band, Min F Mefai Thick- OutlxJs Diameter af Band, Min A C B E Max Min G H- K 0.81 0.73 0.32 :0.38 0.584 0.54C O.UC 0.93 H 0-95 0.80 0.36 .0:44. 0.71 0.675 0.12( 1.12 X 1.12- 0.88 0,43 0.50 0.897 0.840 0.130 -1.34 K 1.31 l 1.50 ivt 1.75 m 1.94 0.98 1.12 1.29 1.43 0.50 0-58 0.67 0.70 0-56 0.62 0.69 0.75 1.107 1.050 0.155 1.385 1.315 0.17C 1.73C 1.660 0.185 1.970 1.900 0.200 1.63 1.95 . 2.39 2.68 2 2.25 2H 2.70 3 3.08 3X 3.42 1.68 1.95 2.17 2.39 0.75 0.92 0.98 1.03 0.84 0.94 1.00 1.06 2.445 2.375 0.220, 2.975 2.875 0.240 3.600 3.500 0.280 4.100 4.000 0.280 3.28 3.86 4.62 5.20 4 3.79 . 2.61 1.08 1.12 4.600 4.500 0.310 5.79 5 4.50 3.05 1.18 1.18 5.663 5.563 0,380 7.05 6. 5.13 3.46 1.28 1.28 6.725 6.625 0.430 8.28 8 6.56 4.28 1.47 1.47 8.725 8.625 0.550 10.63 10 8.08* 5.16 1.68 1.68 10.850 10.750 0.690 13.12 12 9.50* 5.97 1.88 1.88 12.850 12.750 0.800 15.47 From Americas Standard DimtntieTU of Catt-lrm Screwed Fiitxnet. Class 115. A AS BIS-4-1849. All dimeostoux given in inches. * This applies to elbow* sod tees only. tween the contact faces of the flanges. The flange bolts then draw the faces up so tight that the gasket deforms into the face imperfections and thereby provides a tight joint. Gaskets are made of numerous materials, such as cork, paper, fiber, asbestos, metal (iron, steel, copper, etc.), and combinations of metal and some soft material. The proper gasket material to use depends upon the service of the pipe. The material should not be detrimentally affected by the chemical and thermal conditions of the fluid being carried. ' SOUXB-mc fTTTWG BEnOGEWTOR TWEFLAMD-TUBM) RRMCS RAJtQMUBRQ RTTWCS Fig. 2 .... Copper or Brass Tube Fittings VALVES Valves are made with the same end connections as fittings. A brief description of each type follows. rl. Flanged Ends: Made in sizes from Vi in. up. Used when- ever line fittings are flanged and if frequent removal is cpn- templated. Flanged valves facilitate installation when large sizes are used. . . y 2. Screwed Ends: Moat common-type end. Can be used for all pressures. Usually confined to smaller size because of diffi culty in mating large screwed joints. 3. Welding Ends: Available in steel only. Generally employed for high-temperature, high-pressure work. Difficult to disassem ble in a welded line. This type includes butt-welding or socket welding. See Tables 11 and 14 for size of fittings available in each class. The valves are made in the same range. - 4. Brazing Ends: These ends are' available on'brass valves. . The ends have a special shape to facilitate use of brazing alloys. These valves are used for higher temperatures than solder end valves. 442 CHAPTER 31 1959 Guide Table 10 . .. i Dtmensiohs'of Ranged Cast-Iron Elbow, Double Branch Elbows, Tees, Crosses, Laterals, True Y*s (Straight Sizes), and Reducers (Qass'125) ' ' Noctfoaf ' Pipe Size Cantor to foe* bmde Dio of FQSngt 90 0*9 Sbow, fee*. Crone], Tra* Y, and DoubtoBranch Cantor to foe* 90 0*0 tong todiut Bbow . Cantor to Fbc* 45 Deg Bbow . Cantor to Fate lotord Bbow A- ' 6' CD Short Cantor to ton True Y and lateral e . Foe* to Foe* fetfecer f .1 IK . IX 2 2* .1 ix ix 2' 2* - 3*- 3 4' 4* . 5 . . 5 SX 6 6* 7 IX 2 2* 2* 3 '3 3K ` 4 5. .6 '. 3 : . 3* 4 .5 ' -. 6' 6* 6 6* - 7* .8 8 10 12 . HOD 16 OD . 8 10 12 14 . 16 .. 9 11 12 14 15 7* m 9. . m n* 14 ' 16* 19 21* 24 3 3* 4 4* 5. - 5* 6* IK 7X 8 18 OD 20 OD . ,24 OD 30 OD 36 OD 42 OD 4SOD 18 . 16* 26K - .20 . -18 - 29 24 . 22. . , 34 - 30 . . 25 . UK . ... 36 28* , 49 . 42 : 81* 56* , 48 - 34* 64 8* 9* . . 11- 15 18 21 : 5* lK 6K IK ' 72 8 2* 5 9* 2* 5X 10 3 6 n* 3 6* 12 3 7 ' 13* 3*. . 8 . 14* 3* 9 17* 20*. 24K 27 30 4* 11 5 12 5* 14 6 16 6* 18 32 35 40* 49 . 7 8 9 10 19 20 24 30 36 42 . 48 .. Ora of Benge 4* 4* 5 6 7 7* SK 9 10 11 13* 16 19 21 23* 25 27* 32 38* 46 53 59* Thickness Waff of flange TMefcneal (Min) Me * Me X X. K lMe lMe lMe l 1* w. IK IK IKe ix. I1*# IK 2* 2X 2* 2X x. . X. Me Me Me X Me X .X He X X X. K 1 lMe 1* IK. IMe m 1`He 2 From Americas Standard far Ca*t Iran Pip* Flanga and Planted Pittint*, Cls IIS, ASA B1S.1-1W&. Ail dimeuioss enren An ia inches * Dora bM apply to troe or doubfe'flaaced elbow*.... .. 5. Solder nds: For use with copper tube in plumbing, beat ing, and air conditioning. Should not be uaed at hightempera- tufes. ...... .* g. Flared End*: For use with'light-wall tubing, either metal or plastic, and for sices 2 in. and below. A flaring tool flares the tube end, and a ring nut pulls the flared tubing up against a seat on tae.valve: This makes a lap-joint. ' - * . -- 7. Hub Bnds: Generally used for water supply and-sewage piping. This type joint is used with east-iron'pipe. The joint is a socket type made by inserting the pipe in the hub, then c&ulkingiwith oakum. After caulking, the joint is sealed with molten lead. .. - ' V . Valves are made of brass, iron, steeljand.to some extent mftMftfthlft iron. Brass should not be used for work requiring temperatures above 550 F. The brass used in valves is similar to that used in brass pipe and contains some tin and lead1as well as copper and sine. Cast iron is generally provided in some alloyed state, espe cially in the larger sizes. Cast iron alone is not suitable for service (above---450.F-).. . Malleable iron, which is a cast iron heat-treated to provide some ductility, is used to some extent, primarily in place of cast iron. Steel is used either in tbe cast or forged state. For corrosive service, alloy and stainless steel are used. Steel is used for high temperature, high-pressure work. Steel is the only valve ma terial that can stand appreciable expansion stresses. ' The' characteristics of valves restrict their use. The five main uses for valves are listed below: . I. Stopping .flow: The most general use for valves. Gate valves are generally used for thin purpose. Hie gate valve operates by a disc moving at right angles to the path of the Pipe, Fittings, Welding 443 - are used to reduce a high incoming pressure to a required serv ice pressure. These valves are designed to eliminate a fluctua tion in the incoming pressure and thereby maintain a steady, lower service pressure (see Chapter 26). Table 19 contains data on tbe dimensions of flanged and welding end valves. Dimensions of other type valves can be obtained by writing to the Manufacturers Standardisation Society of the Valve and Fitting Industry. WaDING -Erection of {Aping in heating and ventilating installations - by means of fusion welding has been commonly accepted in the past few years as an alternate method to the screwed and flanged joint. Since the question of economy of welding as against' the use of screwed and flanged fittings is dependent on the individual job, the use of welding is generally recom mended on the basis of: greatly reduced cost of maintenance and repair; reduced weight resulting from the use of a lighter- weight pipe; or increased economy in pipe insulation, hang ers, and supports rather than any economy that might be effected in actual erection by welding on low to medium pressure heating jobs.- . " Fusion welding, commonly used in erection of piping, is defined as. the process of joining metal parts in the molten, or molten and vapor states, without the application of me chanical pressure or blows. Fusion welding embraces gas welding and electric arc welding, both of which are commonly used to produce acceptable welds. Welding processes and pro cedure are described in various publications* Welding application requires the same basic knowledge of design as do the other types of assembly, but, in addition, re quires a generous knowledge of welding principles and par ticularly the welding qualities of metal and its reaction to extremely high temperatures. The ability to select and use the proper welding rods is important. This requirement ap plies equally to employer and employee, with the employer accepting all of the responsibility. Thus the employer should Ron Awnem Standard far StmL BwU-WUiv Fitt****, AS<4 B18-9-1931. Ail dimension* an in ioebea- Dimension A a eqoal loHat HiQ. select his welding mechanics with good judgment, provide them with first-class equipment and tools, arrange for their training and use of acceptable workmanship standards, and fluid. The fluid flows straight through the valve, hence, a gate valve offers the minimum resistance when it is fully open. The gate is moved by a stem screw attached to the handle. Gate valves are poor regulators because at nearly closed position (where best'regulation is obtained) the fluid- velocity either causes vibration and noise, or.else tends to erode the disc. at regular intervals subject their work to prescribed tests. Rules for fusion welding of pipe joints, the qualification of welding operators,-welding procedures, and testing are con-, tained in the Standard Manual on Pipe Welding* and in pub lications of other groups.1' * * In general, the wall thirlrnpas 2. Throttling flow: This is best accomplished by globe .or ' and chemical analysis of the pipe are the governing factors, angle valves. These valves cause the fluid to change direction,. and consequently, offer considerable fluid resistance even when . in the open position. Both the globe and angle valves operate by closing a plug into a fitted seat. The angle valve is wimilar not the working pressure. There are a number of safety codes which govern the installation of welded piping in many cities and states. , to the globe valve except that the outlet face is at an of 90 deg from the inlet face. An angle valve takes the place of a globe valve and an elbow. 3. Checking flow: Preventing back flow is called checking, hence, a check valve is used. The basic principle of all check valves is that a reversal of flow will close the valve. Check A complete line of manufactured steel-welding fittings is . now available, and a dimensional standard has been prepared under the procedure of the American Standards Association, (see Table 11) to unify heretofore divergent dimensions for the same type welding fittings produced by different manu v"vs .are either swing check or lift check. With a swing check the fluid presses on a hinged flap. If the flow stops or reverses, the flap swings down ana seats itself to close the valve. A lift meek operates similarly except that the flap is replaced by a facturers. Standard dimensions for steel butt-welding el bows, tees, caps, and lapped-joint stub ends are given in Table 11. Dimensions for eccentric and concentric reducers pl"S that is lifted--through guides---by the force of the fluid are not shown in Table 11, but are included in the standard. flow. The fluid changes direction of flow, as in a globe valve, and transmits a vertical thrust. If tie flow stops, gravity pulls the plug downward and closes the valve. A reversal of flow will close the valve. . Steel butt-welding fittings have beveled ends. For wall thicknesses less than Me in., the bevel may be either 37* deg. or cut square. For wall thicknesses of Me in- to and in cluding Ye in. the bevel is 37* deg. For walls larger than Ye Two other types of valves are the relief valve and the pres in. but not greater than \ Ye in., the bevel is U-shaped with a sure regulating valve. Relief valves are usually spring loaded slope of 20 deg above the Me in. radius fillet. For walls ia order that some predetermined pressure can force tbe greater than 1 Ye in., the welding ends are prepared as agreed valve to open and relieve the pressure. Pressure regulators between the manufacturer and the purchaser. . 8S 444 CHAPTER 31 1959 Guide Table 12 .... Dimensions of Steel Ranged ntiings for Primary Service Pressure Ra sg of 150 Psi (Gage) ELBOW LONG MOMS 45* ELBOW ELBOW - ' TEE CftOSS ** 45' LATERAL 23 *67 9 ,0 " " - Id JS 16 17 IB w 20 . ' ' Vfe fa- *ei*d Foes (Flange Edge) ' King Joint *0 1 III .IIIii 5 1 jS | 1 m tJ 8 3 .il fs's liii h% "a U*g. O .j Itsfs5S'i S 8 I*4 s 1S o o>- 2 . S ffis 3 u Jfs et<2l s s 111 |i<S Hi 2 1 tii 6S" * v3u"" <3 c _| teT _ s sl- si 59 5| ?,* 3" 15 V J- i** 1 S 5 O' c AA SB : 5 cc EE., FF GO HH jj KK 11 MM ft wS li o $ Bob* DriUmg 8 2 & ' || e Tu o 5^ ^a D= --o o" W X TJ Q o o 4K He w 5 iK 5K IK ' 4V* 3K 5K 2 6 2 4H X 3H 5H 2 6H IK 4V* 4 3K 2K 6V* 2 5 He 4 . 6-' 7 2 4V* 4K 6K 2V* 7K 2K 6H 7 `He 7K H * 8K `He 9 `He 4H 5 5H 6 K 6H 2V* 73 7H 3 8H 3H 9 4 8 m 10 UK 12 2V* 2H 3 3 3 5 4K 6K 2K 8K 2K 4K 4K V* K 3K H 5H 5H 7K 3K K 2K 4H 4K V* H 3K H 6 5K 8 3K 10K 3K 4K 5 He K 3H H 6H 6K m '3 11K 3K 5K 5 He K 3K H 7 6K 9H 4K 12K 3K 5K 6 H K 4K K 10 % 11 l 13X IK 16 lHe 19 ' IK m 8' 9 11 12 10K HH 14 16H 19 4V* 5- 5H 6>< ' 7V* 13H I4H 17V* 20V* 24V* 3K 3K 4H 5 5H 8 9 11 12 14 7K 10V* 4K 13K 3K 6K 7 K K 5K H SVi m 5K 14K 3K 7 7 lHe H 6K H 9K 14K 6H 17J4 4K w 9 `He K 7V* Ve UK 16K 6K 20K 5K 9K 9 `He K 7K H 12K 19K 7K 24H 5K UK 11 1 l 9V* K 21 1H 23M lHe 25 lHe 27V* i*H 32 IK 14 15 16V* 18 22 2D* 24 26H 29 34 7H 8 ' 8H w 11 27 30 32 35 40>* 6 6K 7 8 : 9 16 18 19 20 ' 24 14K 21K W 27K 6K ' 12H 11 I6Vi 24H SK 30K 6K 13K a 1 1 l l 9K 9K 16K 26K 8H 32K 7K 15 13V* IK IK 11K 18K 29K 9H 35K 8K 16 13V* IH IK 11H 22K 34K UK 40K 9K 18K 13H jl IK 11K K X X K X Pram Amtrica* Siaadard Jar SUd Pip* Flangnand Flanged Fitting*, ISO, >00,400,800, 900, 1500, ind 2500 Lb. ASA B18-5-U53. All ditoenakum given in Inches * Aetusl dimeter is Mse for Bim I .to IX in. tad is 9< io. lea thsa namififtJ tor2>o 1< to M1&. - ' ' Flange fittings may be welded from sizes Vi to 24 in. in clusive (see'Table 13). . ' Socket-welding fittings also are commercially available. These fittings have a machined recess for inserting the pipe which is attached by a fillet'weld between the pipe wall and socket, end.' Use of socket-welding fittings generally 'is re stricted to nominal pipe sizes 3 ini and smaller in which range commensal fittings are available. This type of fitting has gained rapid acceptance owing to its ease of installation, low cost, and ability to make a pressure-tight joint without weak ening the pipe, as is the case with threading. Dimensions for socket-welding fittings, in accordance with ASA Standard B16.11-1946, are given in Table 14. EXPANSION AND FLEXIBILITY Changes in temperature cause a change in dimensions of any matter. The metals that are used for pipe have the same characteristics in that they expand with increasing tempera ture. If the metal is constrained so that it cannot expand, then an internal compressive stress is set up in the material. Pipe, fittings. Welding Table 13 .... Dimensions of Steel Ranges for Primary Service Pressure Rating of 150 Psi (Gage) 445 LAPPED WELDWG NECK 2 34 5 6 8 "9 10 " 13 14 Noamed HP* Sx Ovhkk TMdaiM Dtommfor of Flange, of Flange Min Orameter of Hub Hub Diameter Beginning of Chamfer WMmg Nock OCX A langtb Through Hub T Shewed slip-on socket welding lapped Welding nodi Bor. . Threod Length Screwed T socket welding, atb Lopped, ' Welding neck socket welding Kodiss of Bore of Lapped Range and Pipe Depth of Socket ft D K 3H He lHe 0.84 H 3X X IK 1.05 l 4H He l`He 1.32 IK 4K X. 2He 1.66 ix 5 `He We 1.90 K X `He We X H H `He `He K IK 2He We 2K 2K., K H `He `He K 0.88 1.09 1.36 .1.70 1.95 0.90 1.11 1.38 1.72 1.97 0.62 0.82 1.05 1.38 1.61 K K K He K 2 6 H 3He 2.38 1 l 2K i 2.44 2.46 2.07 He 2K 7 X 3He 2.88 IX IK 2K IK 2.94 2.97 2.47 He 3 7K `He 4K 3.50 We We 2H We 3.57 3.60 3.07 H 3V* 8K `He 4`He 4.00 IX IK 2`He IK 4.07 4.10 3-55 % 4 9 `He 5He 4.50 We lHe 3 lHe 4.57 4.60 4.03 He X He M He K `Kb K `Kb 5 10 `He 6He 5.56 IK. lHe 3K IK. 5.66 5.69 6 11 1 . 7He 6.63 We lHe 3K lHe 6.72 6.75 8 13K IX 9`He 8.63 iK IK 4 1H 8.72 8.75 10 16 We 12 10.75 me lJHe 4 l`He* 10.88 10.92 12 19 IX MH 12.75 We 2He 4K 2He 12.88 . 12.92 m14 21 15K 16 23K We 18 18 25 We 19K 20 ' 27V* l`X. 22 24 32 W 28K 14.00 16.00 18.00 20.00 24.00 . Ww 2'K. 2H 3K 3K 3He 3`He 4*Hxe 5 5 5K 6`He 6 2K 2K 2`He w 3K 14.14 16.16 18.18 20.20 24.25 14.18 16.19 18.20 20.25 24.25 From A mtriean Standardfor SUtl PiptPlanQt* and Flangti Fitting*, ABA 816S-1I51 All dimenotaaa (iTis in iwrfi--1 5.05 6.07 7.98 10.02 12.00 To be specified by purchaser He K K K K K H H K K This stress can be calculated, just as any other stress, by using Hooke's Law. _ where F =* Force of constraint, pounds. e ~ Deformation, inches. E Modulus of elasticity, pounds per square inch. A Area of metal, square inches. L Length of metal, inches. -- - This equation is valuable in determining the internal stress of the pipe and also the constraining force on the anchors. This equation assumes that the stress is less than the yield strength of the metal. In other words, the metal will return to its original dimension when the temperature returns to its original level. Materials such as cast iron are not ductile, hence the yield strength is approximately equal to the ultimate strength. These materials have excellent compressive strength but poor tensile strength. For this reason, it is difficult to bend these materials appreciably. Cast iron, for example, could be put in tension and, from Table 20, it is seen that for a temperature change of 100 deg, a compressive stress of 7140 psi would be developed. If the pipe were straight, this stress would be handled easily. If, however, the stress caused a bending mo ment, then fracture might occur. ' The values of stress found in Table 20 were determined by using Equation 1 and substituting Equation 2 for e . e *= aL&t (2) where . .' a -- coefficient of linear expansion, inches per inch, at temperature change, Fahrenheit degrees. 446 CHAPTER 31 Table M____ Dimensions of Socket-Welding fittings A. OinHMiii of SadrcSWediig Bbow*. te*, and Con fa W>> jsrr 1959 Guide - JEST Nonnd KpoSixo Dcpifi of Socket, Min Center to loHoa of Socket Sdted 40 and 80 Sdted 160 Boro Diameter of Socket, M<n Socket Waff Thickness, Mia Sdted 40 Sdted 80 Sdted 160 A .C Boro Diameter of Fitting Sdted 40 Sdted 60 D Sdted 160 X K K X H 1 IK iK 2 2K 3 X Ke 0.420 0.125 0.125 0.269 0.215 K K 0.555 0.125 0.149 0.364 0.302 X 0.690 0.125 0.158 0.493 0.423 H X X 0.855 0.136 0.184 0.234 0.622 0.546 0.466 K X X 1.065 0.141 0.193 0.273 0.824 . 0.742 0.614 X X IKe 1.330 0.166 0.224 0.313 1.049 0.957 0.815 X IK* IK 1.675 0.175 0.239 0.313 1.380 1.278 1.160 X IK IK 1.915 0.181 0.250 0.351 1.610 1.500 1.338 X IK IK X IX 2K X 2K 2K 2.406 2.906 3.535 0.193 0.254 0.270 0.273 0.345 0.375 0.429 0.469 0.546 2.067 2.469 3.068 1.939 2.323 2.900 1.689 2.125 2.626 B. Ditiuwiu of Socket-Wefding 45 Oeg Bbowt, CoupJrayj, and Half Coupling* Center to Bottom of Socket for 45 Oog Bit Pipe She Socket, Atm Sdtod 40 and 60 Sdted 160 A Coopimgs Distance Between Bottom* of Socket* E Half CoopSagt, Bottom of . Socket to Opposite Pace Diameter of Socket. Mm Sodcet WaO Thkknost, Min Sdted Sdted Sdted 40 80 160 Bore Diameter of Fitting Sdted. Sdted Sdted 40 80 160 FB C D K X He K K X He K X X He K X X Hb K X X X K He H X H lXt - X lXe 0.420 0.555 0.690 0.855 1.065 0.125 0.125 0.125 0.136 0.141 0.125 0.149 0.158 0.184 0.193 0.234 0.273 0.269 0 364 0.493 0.622 0.824 0.215 0.302 0.423 0.546 0.742 0.466 0.614 1 X Me lXt X IK K lK *K* X IK K K. l X IK 1.330 0.166 0.224 0.313 1.049 0.957 0.815 iK 1.675 0.175 0.239 0.313 1.380 1.278 1.160 IX 1.915 0.181 0.250 0.351 .1.610 1.500 1.338 2 X1 IK 2K X IK IK 3 H IK IK K Xy. IK ilH* IK 2.406 2.906 3.535 0.193 0.273 0.429 2.076 1.939 1.689 0.254 0.345 0.469 2.469 2.323 2.125 0.270 0.375 0.546 3.068 2.900 2.626 From America* Standard for SUfl Soelxt-WtUinf Fitbat*. ASA BM.11-1941 All dimension* ore In inrfme. This gives Equation 3 F * aBAcd. (3) Vahies for a and are given in Table 21 for various pipe materials, to facilitate determination of the stress in an ac tual pipe. The following example illustrates the computation of stress. Example 1: What is the force set up by a 1-in. Schedule 40 steel pipe if the thermal expansion from a 100 deg temperature increase is fully constrained? Answer: From. Table 1, determine that for a 1-in. Schedule 40 steel pipe, the metal area = 0.404 sq in. Then, from Table 21, aE -- 195 psi, and from Equation 3 F - 195 X 0.494 X 100 - 9630 lb. . It is interesting to note that length does not enter into the determination of the constraining force. This is so because the Pipe, Fittings, Welding. Table 15 ..., Dimensions of Malleable 90-^Deg Bbows, Tees, Crosses, and 45-Deg Elbows (Straight Sizes, 150 Lb) ' ELBOW TEC , CROSS AS* ELBOW C*fod, Noau*- Pipe Toot, and Size Center Width to Fad, of of 45-Deg thread, Bond, Bbowt Min Mia Inode Dime' Min Max Atetol Outside Diameter Atilt A C BE GH K 0.69 0.25 0.200 0.405 0:435 0.090 0.693 K 0.81 0.73 0.32 0.215 0.540 0.684 0.095 0.844 K 0.95 0.80 0.36 0.230 0.675 0.719 0.100 1.015 K 1.12 0.88 0.43 0.249 0.840 0.897 0.105 1.197 X 1.31 0.98 0.50 0.273 1.050 1.107 0.120 1.458 l 1.50 1.12 0.58 0.302 1.315 1.385 0.134 1.771 IK 1.75 1.29 0.67 0.341 1.66C 1.730 0.145 2.153 IK 1.94 1.43 0.70 0.368 1.900 1.970 0.155 2.427 2 2.25 2K 2.70 3 3.08 3K 3.42 4 3.79 6 4.50 6 5.13 1.68 1.95 2.17 2.39 0.75 0.92 0.98 1.03 0.422 2.375 2.445 0.173 0.478 2.875 2.975 0.210 0.548 3.500 3.600 0.231 0.604 4.000 4.100 0.248 2.963 3.589 4.285 4.843 2.61 3.05 3.46 1.08 1.18 1.28 0.661 4.500 4.600 07265 0.780 5.563 5.663 0.300 0.900 6.625 6.725 0.336 5.401 6.583 7.767 From American Standard for UaUtMo-Iron Semed Fitti"4*, 150 Ux ASA B16J-1S51. All dimeneiims (ran is inctoe. stress is a unit length function and so is the expansion; there fore, they cancel each other. In other words, if a weight stretches a 10-foot wire 0.10 in., then that same weight would stretch a 100-foot wire one inch. In both cases the elongation was 1 part in 1200. The realization that thermal stress is in dependent of length is important, but often overlooked. Nonetheless, that concept explains the feasibility of utilizing the inherent flexibility of the pipe to take care of expansion. Regardless of the length of pipe between anchors, it is possible to take care of the expansion by putting the force of expansion into the pipe as internal stress. If the pipe is not straight, then the force of expansion will cause a bending moment. The pipe will then be under a com bined stress. The stresses will be longitudinal and transverse, and .to a small extent radial. All of these stresses tend to fracture the pipe, and therefore must be added to malca up what is called allowable combined stress. The Code for Pres sure Piping, ASA. B31.1, published by the ASME, sets up very definite limits for the allowable combined stresses for various pipe materials. For temperatures below 400 F and for piping that is for neither district heating nor power, any standard pipe material may be used. For high-temperature or highpressure work, some text on expansion and flexibility should be consulted. It is beyond the scope of this chapter to de velop the theory of expansion caused by high temperatures. For the simpler problems encountered for temperatures 447 400 F and less, which the heating engineer is more apt to en counter, there are four methods of allowing for expansion. The first method is to use packless expansion joints. These joints include types of bellows expansion joints, rubber, cor rugated copper and other metals. . Rubber-type joints are generally used in vacuum or low- pressure steam lines. Maximum temperature is generally 180 F. If oil is present in the line, rubber-type joints will be attacked. Travel of these joints is up to 1 inch. The travel to be expected can be calculated by using Equation 2. The second type of expansion joint is called a slip joint. This joint allows for expansion by a sliding of a female mem ber over a male member. The joint is kept tight by means of packing. The packing determines the limit of the tempera ture to which the joint may be subjected. The main disad vantage to this joint is that it must be continually inspected for a deterioration of the packing. By using double dip joints, the travel may go to several feet, but generally a single joint allows about a foot of expansion. It is common practice to use slip joints up to 250 psi. The most common method of allowing for expansion in heating systems is to use the swivel joint. This is the third method. The swivel joint was first used with screwed fittings, but it is also used now with welded fittings. With welded el bows, the swivel introduces torsional stress in the elbow and in the swing piece. This type of joint is adequate for taking up the expansion in a header, and preventing fracture of the riser or heating element. The fourth method is to allow the flexibility of the pipe to absorb the stress of expansion. A technique used to reduce the stress in the expanded pipe is to cold spring it before hook ing it up. Cold springing can be used to absorb about one- half the stress. The technique is to install the pipe with an opposite stress. For example, if the pipe were to have a com pression of 2000 psi, then the pipe would be installed with 1000 psi of tension. For refrigeration, the pipe would be cold sprung in compression. For conditions not requiring rigorous analysis, it is per missible to use expansion bends designed by means of Equa tion 4 ' L - 6.16V5I (4) where L " length of pipe, feet. D = OD of pipe, inches. A " deformation, inches (see Equation 2) fiber stress 16,000 pounds per square inch. Fig. 3 .... Measurement of l on Various Pipe Bends 448 CHAPTER 31 1959 Guide Table 16 . Dimensions of Brass or Bronze Screwed 90-Deg Elbows, lees. Crosses, 46*Deg:tibows and Couplings (Straight Sizes 125 lb) ` * - E * f t A lJ --A-- Ll --A-H--A- i"UF-K pJ 00 ELBOW Nominal Pipe, Sim Center to End, Elbow*, reel. Crones length of Center to End Thread, Min 45-Deg Elbow* Dramsfer Wrought Coupling 'node Diameter Band length, of Cast Fitting Metal Thick- Band Diam Min eter, Min Min Max End to End Straight Coupling Cast Wrought A B C D E f GH W K 0.54 0.25 0.42 Kb 0.14 0.41 0.44 0.08 0.67 0.80 0.83 X 0.71 0.32 0.56 Ke 0.16 0.54 0.58 0.08 0.81 0.97 1.03 H 0.82 0.36 0.63 K, 0.17 0.68 0.72 0.09 1.00 1.05 1.11 X 1.01 0.43 0.78 iXe 0.19 0.84 0.90 0.09 1.17 1.29 1.36 .H 1.18 0.50 0.89 Me 0.23 1.05 1.11 0.10 1.42 1.43 1.50 j 1.43 0.58 1.06 in 1.69 0.67 1.22 ix 1.84 0.70 1.30 0.27 0.31 0.34 1.32 1.39 1.66 1.73 1.90 1.97 0.11 0.12 0.13 1.72 2.10 2.38 1.68 1.86 1.92 2 2.12 0.75 1.45 2X 2.70 0.92 1.95 3 3.08 0.98 2.17 4 3.79 1.08 2.61 0.41 0.48 0.55 0.66 2.38 2.88 3.50 4.50 2.45 2.98 3.60 4.60 0.15 0.17 0.19 0.22 2.92 3.49 4.20 5.31 2.20 2.88 3.18 3.69 From American Standard for Bra** or Bronx* Screwed Fitting*. 125 Lb- ASA B15.15-1047. All dimeosioag fiven is inches. Equation 4 can be used for bends with two fittings, regu lar U-bend, and offset U-bend, as shown in Fig. 3. It gives the length of pipe, L, that must be used in the U-bend to take up the deformation, A. When welding fittings are used, the radii should be six times the outside diameter of the pipe. One other restriction is that the pipe should not be heavier than extra strong. . Manufacturers of pipe, or pipe fittings, often publish ex cellent treatises on the simplification of expansion problems. It is suggested that the engineer obtain such publications and also a text or handbook* on the subject before attempting to solve a problem on flexibility. . HANGERS AND SUPPORTS In the preceding section, Equation 3 was developed to give the force of total constraint. This.equation is appropriate re gardless of the sign of At, positive or negative. It did not, however, allow for any bending moment but was for straight compression or tension. If the compressive.force is great enough, or if the line is long enough, a slight eccentricity of the load application will . cause a buckling of the line. This buckling is identical with the action of a column under excessive compression. In fact, a pipe line in compression is identical to a column. Column criteria can therefore be used for selecting the action of sup ports to resist lateral thrust. A common equation' for determining safe column loads is Euler's formula: (for cast iron see Equation 8) (5) where S *= allowable column load, pounds per square inch. k = radius of gyration, inches. . 1 es column length, inches. . I_ (OD) + (ID)* . ' 16 Equation 5 is sometimes modified by a correction factor C to the following: S - C*B (6) where C = correction factor depending on end loading in accord ance with the following table: . ' End Conditions or Column . One End Fixed Fixed Fixed Pin Other End Fixed Free Pin Pin Value of C - . 4.00 0.25 2.25 l.oo Pipe, Fittings, Welding Table 17.... Dlfflessens of .Cast-Brass Solder-Joint Elbows, Tees, and 45-Deg Elbows . (Straight Siin) Tohle IB____ Dimensions of Cast-Brass Solder-Joint Couplings (SfrofgM, Reducing, and Cueufni Sized 449 Of 030* TEE W* ELBOW M* OTEFT ELBOW *i` SincET ELBOW 7 -u r REDUCMG COUPIMG ccccntoc awuNe ft!.! Standard Water Tube Size Center to Ex ternal Shoulder 90-Deg Street Show 45-Deg Show . Center to Ex ternel Shoulder 45-Deg Street Elbow O X H X X X Ms Me Me X Me Me `Me Me Me Me Me X .K 1 X K Me Me 1ix H 1 Kb Me ix IX X K 2 ix 2M ix m IK He K X 3 IK IK X 3K 2 K 4 2K 5 3M 6 3M 8 4% `Me IMe IK 2M From American Standard far Oa*t-Bn** Solder-Joint Fitting*. ASA 615.18 1950. All dimessnas given is inches. * Not gUndardhcd tor wrought fittings. Consult manufacturer for From Equation 6, This equation is not used for column construction but is sufficiently accurate for the work of a heating engineer. The equation is modified for cast iron because of its poor tensile strength. It is generally acceptable to use one-half the value of S from Equation 5 for cast iron, so the safe column load & for cast iron is ,, Si =* **B l/fjcVI for cast iron. ,,(8^) It is permissible to allow the l/k ratio for steel to go as high as 120, but for cast iron the desirable maximum is taken as 70. It is not to be understood that a fracture will' occur at l/k ratios in excess of those given, rather it is to be understood that lateral support should be given for those ratios and for those magnitudes of stress. If an expansion joint is used, this will, of course, relieve the compressive stress. Example S: For Example 1 given ia the preceding section, the constraining force fdr a 1-in. pipe was 9630 lb. What is a required spacing for lateral support for this pipe? STRAIGHT REDUCING ECCEHTUC Standard Water Tube Sire laying length* M Standard Water Tab* Size laying length* N Standard water lube Sire laying length* W X X X _K Me X X X Me 1 X K K IK * l K IK x K Me X* K K K l x K `Me H lKxi K K IK x K K l X IK x iK H IK x IK `Me IK X IK x l X IK xl `Kb IK X IK* H Me 2 x IK IK 2 Kb 2 x IK K 2 X IK Kb 2K Me 2 x IK K 2Kx2 IMe 3 Me 2 xl K 3 x2* IK 3K X 2 x M K 3 x 2 IMe 4 X 2K*2 Me 4 x 3 2 5 X 2KxiK Me 6 X 2K*1K . K 8 X 2Kxl K. 3 X2K 3 x2 4 x3 4 x2M 4 x2 X X Kb IK IMe 6 x4 8 x6 IMe IK From American Standard for Catt-Brai* Solder-Joint Fitting*. ASA BIS.191850. All dirogtwiorw gives in inches. * Not standardised lor arottgkl 6ttiogs- Consult manufacturer tor dimextsioBB. Answer: Using Euler's formula, Equation 5 gives bo i - .tVi/s For a 1 in. Schedule 40 steel pipe k - 0.4205 in. B - 30,000,000 psi. 5 = 9630 -s- 0.494 = 19500 psi. I ~ 51.8 in. Therefore, lateral supports on 4-ft centers are adequate. The other type of load requiring some support is the bend ing stress due to the weight of the pipe, its insulation, and of 450 CHAPTER 31 1959 Guide Table 19 .... Dimensions of Flanged Cast-Iron and Steel Valves Notes for Table 19 From Aowrieon Standard far Pacs-ta-Faa Diustnsums of Ferrous Flawed and Waldim Bad Fata*. ASA B1B.10-1B38. All dimezrfuro* cron in inches. BWn. srs not cron, tbs naes either ere not made or there is in* sufinnnt i\^iyanA to warrant the erpecae of anifieattce. Female shd groove joint hwup have bottom at groove in some plane as sif, and center to contactsuriace dimensions for these taciacs are reduced by th* amount of the raised (see. Tboe are Treasure designationswhich rdei to the primary service ratings in lb par eq in. <A the connect!nc end flanges. b Tl* pmieeeting end flange* of 175 lb valves are tbc tame as those on 250 lb valves. Tto BPnf^*"^**** r,*rtn** Aim+ntinr* nH W1TM-Uny end <1B|M for 400 lb valves S in. use and smaller, are identical with those of 800 lb valves; end the contact surface to contact surface dimsnmona and connecting end flange* for 900 lb valves 1H in- eiae and smaller, ere identical with tboee of 1500 lb valves. Table 20____ Thermal Stresses Due to Total Constraint Temperate*** Change, F Deg Sled Thermo} Sirenet, Fti Wrought Cast Brass or iroa Iron bronze Copp" 20 3900 3800 1428 2760 40 7800 7600 2856 5520 60 11700 11400 4284 8280 80 15600 15200 5712 11040 100 19500 19000 7140 13800 * Far temperatures between SI and 400 F. 2980 59G0 8940 11920 14900 2700 5400 8100 10800 13500 Table 21 . Physical Properties for Determining Thermal Stress (Teaparafarei between 32 ond 400 f) Steel Wrought Cast (roe Cop. Alumpar Coefficient of Linear Expansion, a X 10*... 6.5 Modulus of Elasticity, E, psi X 10"*............... 30 Product of oB, psi......... 195 6.8 28 190 5.95 9.85 9.3 13.5 12 14 16 10 71.4 138 149 135 Bzam-pls: The coeffidest of expansion for steel w 0.0000085 in-/tn. and the modulus of elasticity - 30,000.000 psi. Therefore oB * 185 pai. Table 22____ Equations for bending Stress and Deflection between Supports . type of Support Bending Siren, Po S Deflection, fnche* Y Single span (free Continuous line........ ,, 0-75 WL*D SI 0.5 WL*D ,, 22.5 WL* Y Bl v 4.5 WL4 Bl IP Total weight (pipe, Quid, etc.) pounds per foot. D OD of pipe, inches. L Length of span, feet. E Modulus of elasticity, pounds per square inch. I Moment of inertia, (inches)4. / ijW-gD).]. OD, and ID in inches. Pipe, Fittings, Welding 451 Table 23 .... Application of Pipe, Tube, and Fittings for Heating and Air Conditioning Application Material* Commonly Used Appticofroa Material* Cofuporir Usad Chilled water Type K or L hard copper or black steel, Schedule 40 Cooling tower - Type K or L hard copper, wrought iron, or black steel. Schedule 40 Underground water 2-in. and smaller 2)4-in. and larger Type K, soft copper or gal vanized steel, Schedule 40 (for corrosive soils, a coated steelpipe should be used) Type K, soft copper, cast iron. Class 150 or galvanized steel, Schedule 40 (for cor rosive soils, a coated ateel pipe should be used) City water--inside building Type K or L, hard copper or galvanized steel. Schedule 40 Underground rain water con ductors Small installations Under paved areas Large installations 8-in. and smaller 10 to 24-in. 30-in. and larger 5 feet outside bldg, and under paving Vitrified clay or cast-iron soil Cast-iron soil Cast-iron soil XH or vitrified clay Vitrified clay or concrete Concrete Cast-iron soil XH Interior rain water conduc tors Small installations Large installations Black or galvanized wrought iron or steel Schedule 40 Cast-iron soil XH, black or galvanized wrought iron or steel, Schedule 40 Panel heating* Type K or L soft copper. Black steel or wrought iron. Schedule 40 Hot water heating* Type K, hard copper or black steel. Schedule 40 Refrigerant* Type K or L hard copper or Mack steel, Schedule 40 Stean^ heating Supply 125 psi and less 125 to 250 psi Return pipe All sizes Black steel, Schedule 40, standard fittings Black steel, Schedule 40. For fittings see Table 8 Black wrought iron or steel. Schedule 40. Standard fit tings Receiver vent AH sizes Galvanized wrought iron or steel, Schedule 40. Standard fittings Sanitary4 Small installations Waste: l)*iu- and smaller Galvanized wrought iron or steel, Schedule 40 2-in. and larger Vents: 2^-in. and smaller Cast iron Galvanized wrought iron or steel, Schedule 40 3-in. and larger Cast iron Large installations Waste: 2-in. and larger . Cast iron Vents: 2-in. and larger Cast iron Gas (aU kinds) AH sizes ' Black steel. Schedule 40. Maiieable iron fittings * Panel beating copper fittings should be soldered with. 954 solder. Steel fittings steroid be welded. All underground feed and return lines buried in slab, ahould be equipped with fittings as outlined for * Refrigerant fittings on copper pipe must be wrought oopper. All welded fittings should be l"g turn. * House sewer to main should be eset iron Xw. halting the fluid being carried. There is also the bending moment that may be caused by the flexure of the pipe. For this chap ter, however, the flexure loading will not be treated for the reason of complexity, as previously stated for the problem of expansion. Since hangers should always be designed to take the bend ing moment (including buckling) from the pipe, it is neces sary to design the hangers or supports for the maximum bending stress. Even with perfect support spacing there will be some sagging; therefore, the supports should be on a gradient if it is necessary to prevent pockets. Such a condi tion arises for condensate piping. Typical bending and deflection equations are given in Table 22 in order that supports can be properly sized, and if neces sary, pitched. These equations are typical beam equations. If more complex loadings exist, proper beam equations ran be applied. Such equations are found in standard texts on mechanics of materials. By application of the equations given in this section and the section on Expansion and Flexibility, it is possible to de termine the proper location and type of support for straight lines. The types are anchors and hangers. Anchors are used to guide the expansion (sliding anchors) or to fix the pipe. They are needed to take the stress out of the line and translate the stresses to the foundations. In that way all stress can be taken out of the line before it can be transferred to such equipment as boilers or pumps. By means of solid anchors, the anchors can be used to divide the piping into isolated sections that cannot transmit the stresses to other sections. ' Hangers are used to support the piping and to take out the bending stresses. They are of the spring, roller, or rod type. Such types generally allow the free movement of the pipe and yet maintain full support. The Code for Pressure Piping, ASA B31.1, has strict re quirements for the materials used in hangers and supports. The structural properties have a safety factor of five, and consequently there is little chance of failure due to a sud den change of load. There is a type of support for almost everv conceivable 452 CHAPTER 31 1959 Guide requirement. Complete information can best be obtained from a hanger manufacturer. APPLICATION OF PIPE, TUBE, AND FITTINGS In the application of pipe, tube, and fittings it is necessary to comply with regulations contained in local codes and ordi nances. Table 23 is offered as a guide to current practice in hpftt.tTig and air conditioning. It is based on practice in a num ber of consulting engineers* offices and information extracted from Reference 7. It should be borne in mind that selection of material to be used will also be influenced by the familiar ity of local artisans with methods of using different materials. REFERENCES 1 American Standard Code for Pressure Piping (American Standards Association, ASA B-31.1, 1942). - 1 API Specification 6L for Line Pipe (American Petroleum Institute). . . 'Standard Manual on Pipe Welding (Heating, Piping and Air Conditioning Contractors National Association, 1951, 2nd ed.). Welding Handbook (American Welding Society, 1942). 4 ASME Power Boiler Code (American Society of Mechanical Engineers). ` Marine Engineering Regulations of the Coast Guard (Amer ican Bureau of Shipping). Welding (General Specifications for Inspection of Material, Appendix VII, U. S. Nary). General-- for vessels of the U. S. Navy (Specifications for Welding, Ap pendix 5, Part 1, Bureau of Ships, April 1940). 'Sabin Crocker: Piping Handbook (McGraw-Hill Book Co., New York). E. A. Wert, S. Smith, and E. T. Cope: A Manual for the Design of Piping for PlexxbUUy by the Use of Graphs (The Detroit Edison Company). *C. S. Beard: Control valves and positioners (Industry and Power, March 1953, p. 67). CHAPTER 32 PIPE AND INDUSTRIAL INSULATION Industrial Insulation: Uses, Properties, Temperofyre Range of Use, Temperature Limitations, Forms/ Bare Surface Heat Loss/ Conductivities; Heat Flow Calculations; Thickness for Application; Economical Thickness,Low Temperature Insulation; Insulation to Prevent Freezing; Application; Underground Insulations THE PAST 50 years have seen an enormous increase in insulation the user should consult the manufacturer or obtain the use of thermal insulation by industry. Where once the results of unbiased tests. it was not uncommon to see hot water and steam lines, and Other properties of thermal insulations that are of more or even boiler surfaces, uninsulated, it is now rare indeed to see less importance, depending upon the use, are strength, hard any surface operating more than a little above or below am ness, density, compressibility, specific beat, resistance to high bient temperature without insulation. Higher costs of fuel, or low temperature, and thermal coefficient of expansion. The increased efficiency of industrial operations, and the necessity final choice of an insulating material for a given purpose for close control of the temperature of industrial processes usually involves a compromise with regard to several de are among the factors that have caused this greatly increased sirable properties. For example, an insulating firebrick must usage of thermal insulation.. have considerable strength and must be resistant to the tem USES OF INDUSTRIAL INSULATioN perature to which it is to be exposed. The desirable properties of low conductivity and light, weight must be sacrificed to Thermal insulation serves five principal purposes: (1) to conserve heat or some other form of energy, for example, some extent to achieve these necessary properties of strength and temperature resistance. '* electrical energy to operate a refrigeration compressor; (2) to increase the comfort of living spaces; (3) to facilitate con trol of the temperature of a process; (4) to reduce the tern--- TEMPERATURE RANGE OF USE OF INDUSTRIAL INSULATION . perature of the shell of a pressure vessel; and (5) to control the external temperature of the insulated space in order to avoid danger to personnel, to protect surrounding structural members from damage by high temperature, to reduce the ' temperature of working spaces, and, in case of equipment operating below ambient temperatures, to prevent sweating or icing at the warmer surface. Depending on the application, one or another purpose may govern the choice of insulation; usually' two or more are concurrently of importance. . Since thermal insulation reduces the exchange of heat en ergy between an insulated surface and its surroundings, it can be useful at any temperature' from the lowest to the highest. Actually insulation is used in industrial processes operating at temperatures from --400 F to +3000 F and higher. At the low end of the scale are processes involving liquefied gases, usually in vessels or piping, at temperatures from the lowest up to about --40 F. From --40 to normal atmospheric PROPERTIES OF INSULATIONS temperatures large amounts of low temperature insulation are used for enclosing freezing tunnels, cold storage rooms, Low thermal conductivity is the property that distin and a great variety of food and industrial processes, requiring guishes a thermal insulation. Thermal conductivity is defined low temperatures. as the rate of heat flow through unit area of a homogeneous At normal and near-normal temperatures insulation in substance under the influence of unit temperature gradient building structures is required for economical' operation of in the direction perpendicular to the area. Many units have heating and air-conditioning systems. Insulation for heating . been used to express thermal conductivity but the most com and cooling equipment and for the distribution ducts, piping, mon engineering unit is Btu (hour) (square foot) (Fahren etc., is, however, usually considered as industrial. The range heit degree per inch of thickness). The usual symbol for of temperatures is from that of chilled water or about 32 F thermal conductivity is A;. . up to steam at 100-125 psig (about 350 F).. i. Reflective insulations, such as aluminum and steel coated Drying and hairing ovens, small and large boilers, distilla with a reflecting coating, depend not upon low thermal con tion equipment in oil refineries, and high-pressure and super- - ductivity for their resistance to heat flow, but upon the low heated steam piping call for insulation suitable up to *1200 F. thermal emissivity of their surfaces and subdivision of the Petroleum cracking units, heat treating furnaces, and ceramic air space. To be effective in retarding heat flow by radiation, kilns may reach 2200-2400 F. Still higher temperatures with the reflective surface must face an air space. ' surfaces to be insulated up to 3000 F are found on melting fur Thermal conductivity values of the most commonly used naces for glass, iron, steel, and metals of all kinds as well as industrial and pipe insulations are shown in Table 1. These furnace enclosures for combustion spaces for many kinds of values, have been selected as typical and useful for engineering heating units. . calculations, and may or may not apply to a particular ma Above 3000 F the variety of materials physically suited for terial or application. For accurate values for a particular walls and structural parts decreases rapidly with increasing 453 454 CHAPTER 32 1959 Guide Table 1 . . .. Thermal Conductivity (Jb) of Industrial and Pipe Insulations (for Mean Temperature* fixiiurfed} . Expreued m ttv per (boor) (iquore foot] (FafareeAeH depree tempergtwre d/ffertnc* per tnj Maiorial (Coapostion) Accopfod ' Max. Dwmty Qp. for Ib/CvFt U**F 40 Typhat Conductivity It ot Moan Toap. Fahr. 70 too 200 300 500 700 900 BLAN KETS MINERAL WOOL (Rock, Slag, or Glass) Metal Reinforced Felt-Flexible Type. . Felt-Semi-Rigjd Type VEGETABLE A ANIMAL FIBER Hair Felt or Hair Felt plus Jute 1200 450 450; 6-15 0.5-3 2-8 6.23 0,24 0.25 0.25 0.29 0.26 0.27 0.35 0.34 0.35 0.42 0.45 0.44 0.56 180 10 ` 0.27 0.28 0.30 BLOCKS ASBESTOS AND Molded Amosite A Binder BOARDS Laminated Asbestos Paper Corrugated A Laminated Asbestos Paper - 4 ply . - 6 ply .. 8 ply .. . * CALCIUM SILICATE CELLULAR GLASS . CORKBOARD (Without Added Binder) DIATOMACEOUS SILICA 1200 700 300 300 300 1200 800 200 1500 1900 18 0.37 0.40 0.47 0.56 0.66 0.76 30 0.40 0.45 0.50 0.60 11-13 15-17 18-20 0.54 0.57 0.68 0.80 0.49 0.51 0.59 0.69 0.47 0.49 0.57 0.65 11 9 6.5-8 22 25 ' 0.37 0.26 0.39 0.27 0.33 0.41 0.28 0.38 0.48 0.43 0.55 0.53 0.60 0.70 0.64 0.64 0.75 0.75 0.68 0.80 85% MAGNESIA Mag. Carb. A Asbestos . .. MINERAL WOOL (Rock, Slag or Glass) Low Temp. (Asphalt or Resia Bonded) High Temp. (Resin Bonded) ' (With Inorganic Binder). PLASTICS (Foamed) RUBBER (Foamed) 600 11-14 0.35 0.38 0.42 0.46 200 .600 1600 175 150 6-18 0.28 0.29 0.30 6-10 0.28 0.35 0.43 16-24 0-34 0.39 0.44 0.54 0.64 1.6. - 0.26 0:28 0.30 .6 0.23 0.24 0.25 PIPE IN ASBESTOS SULA Molded Amosite A Binder ' TION Laminated Asbestos Paper Corrugated A Laminated Asbestos Paper. 4 Ply per in. 6 Ply per in. ' '' ' 8 Ply per in. 1200 . 700 300 300 300 16 30 11-13 15-17 18-20 0.33 0.38 0.43 0.53 0.40 0.45 0.50 0.60 0.54 6.57 0.62 0.80 0.49 0.51 0.59 0.69 0.47 0.49 0.57 0.65 CALCIUM SILICATE Calc. Sil. A Asbestos CELLULAR GLASS' ` CORK {Without Added Binder) DIATOMACEOUS SILICA 1200 800 200 1500 1900 11 9 7-10 22 25 0.37 0.27 0.39 0.28 0.36 0.41 0.29 0.40 0.48 0.30 0.44 0.55 0.55 0.64 0.70 0.66 0.75 0.71 0.80 85% MAGNESIA ' ' Mag. Carb. A Asbestos - ' 600 MINERAL WOOL (Rock, Slag or Glass) ; Low Temp. (Asphalt or Resin Bonded) Low Temp. (Fine Fiber Resin'Bonded) * ' High Temp. Blanket-Type (Metal Rein forced) . 200 " 450 1200 PLASTICS (Foamed) RUBBER (Foamed) . ` 175 150 11-14 0.39 0.42 0.45 0.51 15 0.28 0.30 0.33 0.39 3 0.22 0.23 0.24 0.27 0.31 6-15 0.29 0.36 0.42 0.56 1.6 0.26 0.28 0.31 5 0.23 0.24 0.25 VEGETABLE A ANIMAL FIBER Wool Felt Hair Felt or Hair Felt plus Jute 180 20 180 ; 10 0.29 0.31 0.33 0.27 0.28 0.30 INSUBAT ING CE MENT 85% MAGNESIA Mag. Carb. A Asbestos - ' MINERAL WOOL (Rock, Slag or Glass) With Colloidal Clay Binder 600 18 1800 24-30 0.46 0.52 0.58 0.49 0.61 0,73 0.83 ' * TtwM Cemperuurea are feiwnUty accepted a* maximum. WbeO operating temperature approaches them limits the Um&ufactarer'a ieoo>PBier>datlnna ahould be followed. . ,. - - Pipe and Industrial Insulation 455 temperature. Insulation for conservation of heat energy must, therefore, often be applied so as to permit enough heat to escape to retain mechanical strength. TEMPERATURE LIMITATIONS OF INSULATIONS Probably the greatest volume of low temperature insula tion is used for temperatures from minus 100 F to atmos pheric. The effect of temperature alone on physical integrity is not ordinarily very important for most types in the low temperature field. There are more definite limitations for materials in the high temperature field where decomposition, excessive linear shrinkage, softening, or some other effect of temperature alone will put a maximum limit on the tempera ture for which a material is suited. As extremes in tempera ture are approached, both high and low, the selection of a material for a specific service becomes more critical and must be based on experience and factual performance data. FORMS OF INSULATION The physical form of industrial insulations varies from powders and loose fills which might be called formless, through materials with varying degrees of compressibility and flexibility, to completely rigid shapes often referred to as preformed insulation. After deciding that a material has the necessary insulating value, physical properties, and tem perature resistance, the choice of the form desired will usually be governed by considerations of material and application cost. The application method and cost in turn will be greatly affected by the. nature of the surface to be covered. Loose fills such as powders and granules must be supported in place by retaining walls, coverings, etc. for application on vertical surfaces and on the underride of horizontal surfaces. Insulating cement is a loose material which when mixed with water to obtain plasticity and adhesion, may be trowelled on a surface and dried in place to serve as insulation. Both loose-fill and cement are especially suited-for covering uneven and irregular surfaces. Flexible and nonrigid insulations are generally grouped as blanket insulation, and are available in many types and varieties, both organic and inorganic, with and without binders, and with reinforcing coverings on one or both sides. Only inherently fibrous materials are generally suited for blanket insulation. Such materials are wood, cotton, and hair in the organic field, and asbestos and mineral wool in the in organic field. Coverings and facings such as paper, aluminum, asbestos sheet, wire mesh, metal lath, may be used as re inforcing, vapor barriers, reflective surfaces, or surface fin ishes in general. Thicknesses and shapes may be of any di mension that c.n be handled although standard sizes are generally used. Some blanket insulations are prepared in roll form for economical shipping. Rigid materials are preformed during manufacture to standard lengths, widths, and thicknesses of a size that can be handled readily. In the case of insulation for pipes and cylindrical surfaces the radius of curvature is varied to suit all standard sizes of pipe and tubing. Some materials are offered in shapes curved to fit greater radii up to several feet or more. Material in rectangular dimensions is usually called block, board, or sheets, the name varying with custom for particular uses. Most common sizes of block insulation are 36 in. long, 6 in. or 12 in. wide, and in thicknesses ranging from 1 to 4 in. Boards in the building insulation field range up to 12 ft long by 4 ft wide with the thickness usually Vt to 1 in. but ranging up to W% in. Smaller boards, or sheets, are used on air-conditioning ducts, equipment, and in. cold storage. BARE SURFAGE HEAT LOSSES-- FLAT SURFACES AND PIPE Heat losses from or to uninsulated surfaces of pipes, ducts, vessels, or furnaces may be of considerable magnitude if the temperature of the surrounding medium differs appreciably from that of the surface. Losses are increased by motion of the surrounding air or by contact of the hot or cold surface with bodies of high conductivity. Good design, therefore, must include consideration of such heat losses and provision for adequate insulation wherever needed. The basic principles of heat loss from surfaces are discussed in Chapter 5. In that chapter radiation and convection are treated separately. . Heat losses from horizontal bare steel pipes, based on tests at Mellon Institute and calculated from the fundamental radiation and convection equations (Chapter 5), are given in Table 2. This table also gives the heat losses or .surface con ductances for flat vertical and horizontal surfaces for surface temperatures up to 1080 F with the surrounding air at 80 F. The surface per linear foot of pipe is given in the second column of Table 2. . . ~ Heat losses from tarnished copper pipe and tube are given in Table 3. The surface per linear foot of tube is given in Table 4. Table 3, Section A, of Chapter 9 alsn gives the sur face conductances for flat surfaces of different :emissivities and orientations in contact with still air. Table & gives the area in square feet of flanges and fittings for various standard pipe sizes. These tables can be used to advantage in estimat ing the amount of insulation required. Examples 1 and t show how the annual heat loss from un covered pipe and its dollar value may be computed from the data in Table 2. Example 1: Compute the total annual heat loss from 165 ft of 2 in. bare pipe in service 4000 hr per year. The pipe is carry ing steam at 10 psi pressure and is exposed to an average air temperature of 80 F. Solution: The pipe temperature is taken as the steam tem perature, which is 239.4 F, obtained by interpolation from Steam Tables. The temperature difference between the pipe and air -- 239.4 -- 80 = 159.4 F. By interpolation in Table 2 between tem perature differences of 150 ana 200 F, the heat loss from a 2-in. pipe at a temperature difference of 159.4 F is found to be 2615 Btu per (hr) (sq ft) (F deg). The total annual heat.loss from the entire line -- 2615 X 159.4 X 0622 (linear ft factor) X 165 (linear ft) X 4000 (hr) - 171,100 Mb. (Mb = 1000 Btu.) Example 9: Coal costing $1160 per ton and having a calorific value of 13,000 Btu per pound is being burned in the furnace supplying steam to the pipe line given in die previous example. If the system is operating at an overall efficiency of 55 percent, determine the monetary value of the annual heat los from the line. Solution: The cost of heat per 1000 Mb supplied to the sys tem = l/WOflOO X 115 (dollars) [13600 (Btu) X 2000 (lb) X 055 (efficiency)) = $0504. The total cost of heat lost per year = 0504 X 17U (thousand Mb) = $13756. . CONDUCTIVITY OF INDUSTRIAL INSULATIONS The conductivities of various materials used for insulating steam and hot water systems are given in Table 1. They are given as functions of the mean temperatures or the arithmetic mean of the inner and outer surface temperatures of the in sulations. . . HEAT ROW . CALCULATIONS The heat losses through 1, lVi, and 2-in. thick pipe insula tion on various size pipes for various temperature differences 456 CHAPTER 32 1959 Guide Table 2 .... Heat Losses from Horizontal Bare Steei ripe* and Fiat Surfaces ' (a &fu per (Sq Ft of Pipe Surface) (Hour) (F Deg Temperature Difference Between Pipe and Air) Pip* linear Temperature Difference F Deg Between Pipe Surface end Surrounding Air. Air at 80 F. tncbei 50 too 150 200 250 300 350 400 450 500 550 600 650 700 750 600 850 900 950 1000 H 0.220 2 1? 2.48 2 80 3.10 3.42 3 74 4.07 4.47 4.86 5.28 5.72 6.19 6.69 7.22 7.79 8.39 9.03 9.70 10.42 11.18 0.275 2.08 2.43 2.74 3.04 3 35 3.67 4.00 4.40 4.79 5.21 5.65 6.12 6.61 7.15 7.71 8.31 8.95 9.62 10.34 LI.09 0.344 2.04 2.38 2.69 2.99 3.30 3,61 3.94 4.33 4.72 5.14 5.58 .6.05 6.64 7.07 7.64 8.23 8.87 9.55 10.26 11.02 IK 0.435 2.00 2.34 2.64 2.93 3.24 3.55 3.88 4.27 4.66 5.07 5.51 6.97 6.47 V.UU 7.56 8.16 8.79 9.47 10.18 10.94 1$ 0.497 1.98 2.31 2.61 2.90 3.20 3.52 3.84 4.23 4.62 5.03 5.47 5.93 6.43 6.96 7.52 8.12 8-75 9.43 10.14 10.89 2 0.622 1.95 2.27 2 56 2 85 3.15 3.46 3-78 4.17 4.66 4.97 5.41 5.87 6.37 6.89 7.45 8.05 8.68 9.36 10.07 10.82 2K 0.753 1.92 2.23 2.52 2.81 3.11 3,42 3.74 4.12 4.51 4.92 5.36 5.82 6.31 6.84 7.40 7.99 8.63 9.36 10.01 io. V? 3 0.916 1.89 2.20 2.49 2.77 3.07 3.37 3.69 4.08 4.46 4.8"/ 5.31 5.77 6.26 6.79 7.35 7.94 8:57 9.25 9.96 10.71 3X 1.047 1.87 2.18 2.46 2.74 3.04 3.34 3.66 4.as 4.43 4.84 5.27 5.73 6.23 6.75 7.31 7.91 8.54 9.21 9.92 10.67 1.85 2.16 2.44 2.72 3.01 3.32 3.64 4.02 4.40 4.81 6.25 5.71 6.20 6.72 7.28 l ,K7 8.51 9.18 9.89 10.64 4K 1.309 1.84 2.14 2.42 2 70 2.99 3.30 3.61 4.00 4.38 4.79 5.22 5.68 6.17 6.69 7.25 7.85 8.48 9.15 9.86 10.61 5 1.456 1-83 2.13 2.40 2.68 2.97 3.28 3.59 3.97 4.35 4.76 5.20 5.65 6.15 6.68 7.23 7.82 8.45 9.12 9.83 10.58 1.734 1.80 2.10 2.37 2.65 2.94 3.24 3.55 3.94 4.32 4.72 5.16 5.61 6.10 6.63 7.19 7 78 8.41 9 08 9.79 10.54 7 1.996 1.79 2.08 2.35 2.63 2.91 3.21 3.52 3.91 4.29 4.69 5.13 5.58 6.07 6.6C 7.15 7.75 8.38 9.05 9.76 10.5J 8 2.258 1 77 2.06 2.32 2 60 2.89 3.19 3.50 3.88 4.20 4.67 5.10 5.50 6 as 6.57 7.12 7.72 8.35 9.02 9.73 10.48 0 2.520 1.76 2.05 2.31 2.59 2.87 3.17 3.48 3.86 4.24 4.65 5.08 5.53 6.02 6.54 7.10 1.69 8.32 8.99 9.70 10.45 10 2.814. 1.75 2.03 2.30 2.57 2.85 3.15 3.46 3.84 4.22 4.62 5.as 5.51 6.00 6.52 7.08 7.67 8.30 8.97 9.68 10.43 12 3.338 1.73 2.01 2.27 2.54 2.83 3.12 3.43 3.81 4.19 4.59 S.02 5.48 5.96 6.48 7.04 7.63 8.26 8.93 9.64 10.39 3.665 1.72 2.0C 2.26 2.53 2.81 3 11 3.41 3.79 `4.17 4.57 5.00 5.40 5.94 6.47 7.02 7.61 8.24 8 91 9.62 10.37 16 4.189 1.70 1.98 2.24 2.51 2.79 3.08 3.39 3.77 4.14 4.55 4.98 5.43 5.92 6.44 6.99 7.59 8.21 8.88 9.59 10.34 18 20 24 face 4.717 5.5536 6.283 1.69 1.6S 1.6C 1.84 1.96 1.95 1.92 2.14 2.22 2.2) 2.U 2.42 2.49 2.47 2.45 2.7C 2.77 2.75 2.72 3.0C 3.07 3.05 3 0? 3.3C 3 37 3.3 3.33 3.62 3.75 4.12 4.53 3.73 4.11 4.51 3.70 4.07 4.45 4.00 4.35 4.71 4.96 4.94 4.91 5.22 5,41 6.39 5.30 5.68 5.90 5.88 5.84 6.17 6.42 6.41 6.36 6.7C 6.97 7.56 6.95 7.54 6.92 7.51 7.20 7.85 8.19 8.86 9.57 10.32 8.17 8.84 9.55 10.29 8.14 8.81 9.51 10.26 8.4* 9.15 9.80 10.62 Horisontal Surface Facing ` Upward - 2.03 2.37 2.67 2.97 3.28 3.59 3.92 4.31 4.70 5.12 5.56 6.02 6.52 7.05 7.61 8.21 8.86 9.52 10.24 10.99 Horizontal Surface Facing Downward 1.61 1.86 2.11 2.36 2.64 2.93 3.23 3.60 3.97 4.37 4.80 5.25 5.73 6.25 6.80 7.39 8.02 8.69 9.39 10.14 Values are foe flat Surfaces four eooare feet or more in area. . .- To secure <"-- per --r foot, multiply aq ft lasses in by this factor. The losses per sq ft of pipe surface for pipes larger than ?4 in. can be cousidered the same as ths lessee for the pipe. ' ' ' between the pipe and the surrounding atmosphere up to 525 F, are shown in Figs. 1,2, and 3. . The actual thicknes of many molded pipe coverings is not exactly 1 in. However, the loss through any given thick ness of insulation can be obtained by interpolation. - The heat losses through 1, lVz, and 2-in. thick block, blanket, or cement insulation when applied to a flat vertical surface is given in Fig. 4. . The lceses through any of the insulations given in Table 1 <*n be obtained by multiplying the losses obtained from Figs. 1,2,3, or 4 by the factors given in Table 6. . .. Pipes operating at high temperatures are frequently in sulated to the best advantage by combining a high tempera ture ingi^ntinn near the pipe with a' moderate or low tem perature insulation around it as an outer layer. By this method an efficient material may be used for each of the two temperature ranges encountered. In calculating the heat loss through such a combination the mean temperature of each layer must be' determined along with the thickness of each. This is readily, done in two or three calculations performed as a series of approximations, in which assumptions of thick ness and mean temperature are adjusted as indicated in the discussion which follows. ' In the'case of a angle thickness of pipe covering, the quan tity of heat transferred per square foot of outer surface of the insulation is given by the equation: a <i) r, log. --r* T\ where 9. TM Btu per (hour) (square foot of outer surface of insula tion). ' . n " outer radius of pipe or inner radius of insulation, inches.. r* -- outer radius of insulation, inches. k = thermal conductivity of insulation,, Btu per (hour) (square foot) (Fahrenheit degree per inch). It temperature of inner surface of insulation, Fahrenheit. tt *= temperature of outer surface of insulation, Fahrenheit. Pipe and Industrial Insulation 457 Table 3 .... Heat Loss from Horizontal . Tarnished Copper Fipe1 Expmstd bt BJu per (boar) (linear foot) (Fahrenheit degree difference between the pipe and arroaading pill air at 70 f) Hoi Wafer (Type K Cbpper Tube) Steam (Standard Pipe Size Fipe) Nominal Pipe 120F Site 150 F 180 F 210 F 227.1 F (5 prig) 2977 F (50 prig) 337.9 F (100 prig) Temperature Difference--F Oeg Table A .... External Surface per Linear Foot of Copper Tubing Oofride diameter X in. greater fhoa nominal dxe Tube Size Surface Ana (Inciter) (Sq Ff) (fnchei) Surface Area Tube Size SorfoceArea (Sq Ff) (incited (Sq Ff) K 0.164 2 0.556 5 1.342 X 0.229 2X 0.687 6 1.604 1 - 0.295 3 0.818 8 2.128 IK 0.360 m 0.949 IX 0.426 4 1.080 50 80 110 140 157.1 2277 267.9 X 0.250 0.287 0.300 0.321 0.433 0.500 0.530 H 0.340 0.381 0.409 0.429 0.533 0.543 0.654 l 0.440 0.475 0.509 0.536 0.636 0.746 0.803 1H 0.500 0.559 0.618 0.622 0.764 0.878 0.934 IX 0.580 0.656 0.710 0.750 0.904 1.053 1.120 2 0.730 0.825 0.890 0.957 1.101 1.273 1.364 2* 0.880 1.000 1.091 1.143 1.305 1.490 1.605 3 1.040 1.175 1.272 1.343 1.560 1.800 1.940 3K 1.180 1.350 1.454 1.535 1.750 2.020 2.170 4 1.460 .1.500 1.635 1.715 1.941 2.240 2.430 *X 5 2.131 2.465 2.650 i.600 i.812 i .980 2.071 2.387 2.770 2.990 6 1.840 2.125 2.270 2.430 2.740 3.210 3.440 8 2.400 2.685 2.910 3.110 3.310 4.050 4.370 The heat I06S through two or more thicknesses of insulation applied to a pipe can be calculated by means of the equation: r. liog. --r* r, lo, g, --u r ,r where r = outer radius of second layer of insulation, inches. r, = outer radius of last layer of insulation. Inches. The method of solving Equation 2, which is the most diffi cult of the two, is given in Example 3. It is convenient to work from the outer surface of the in sulation, since the loss through the covering must be determined'from the outer surface loss by means of surface Joss curves such as given in Fig. 5. The curves were plotted from tests conducted at the Mellon Institute. After the true heat loss is obtained, the loss per square foot of pipe surface can be calculated from the relationship: ?. - 9.(rj/ri) , where 9> = Btu per (hour) (square foot outer surface of pipe). Example 3: Compute the heat loss per linear foot of pipe sur face per hour from a 6-in. pipe, insulated with a 3-in. tiijnlmww of 1500 F diatomaceous earth, and a nominal 2-in. thickness of 85 percent magnesia. The pipe is operating at a temperature of 1200 F and is exposed to a room temperature of 80 F. Solution:. In figuring the heat loss from Equation 2, it is necessary to first make an assumption for the outer surface tem perature tt and the temperature between the diatomaceous earth and 85 percent magnesia insulation, so that the mean tempera ture of each material can be obtained and the thermal conduc tivity corresponding to the mean temperature of each material substituted in the equation. First assume an outer surface tem perature of 135 F and a temperature of 570 F between the two materials corresponding to a mean temperature of (1200 + 570) 2 or 885 F for the diatomaceous earth and (570 + 135) 2 or 352.5 F for tile 85 percent magnogjn insulation. The conduc- Table 5 .... Area of Hanged fittings, Square Feet* Nominal Pipe Sue (Incber) Flanged Coupling Standard Extra 90 Deg Bi long Rodfo SI Tee Croxa Standard Extra Heavy Standard Extra Heavy Standard Extra Heavy Standard Extra . Heavy 1 0.320 0.438 0.795 1.015 0.892 1.083 1.235 1.575 1.622 2.07 IK 0.383 0.510 0.957 1.098 1.084 1.340 1.481 1.925 1.943 2.53 IX 0.477 0.727 1.174 1.332 1.337 1.874 1.815 2.68 2.38 3.54 0.672 0.848 1.65 2.01 1.84 2.16 2.54 3.09 3.32 4.06 2X 0.841 1.107 2.09 2.57 2.32 2.76 3.21 4.05 4.19 5.17 3 0.945 1.484 2.38 3.49 2.68 3.74 3.66 5.33 4.77 6.95 3K 1.122 1.644 2.9$ 3.96 3.28 4.28 4.4S 6.04 5.83 7.89 4 1.344 1,914 3.53 4.64 3.96 4.99 5.41 7.07 7.03 9.24 4K 1.474 2.04 3.95 5.02 4.43 5.46 6.07 7.72 7.87 10.07 5 1.622 2.18 4.44 5.47 5.00 6.02 6.81 8.52 8.82 10.97 6 1.82 2.78 5.13 6.99 5.99 7.76 7.84 10.64 10.08 13.75 8 2.41 3.77 6.98 9.76 8.56 11.09 10.55 14.74 13.44 18.97 3.43 5.20 10.18 13.58 12.35 15.60 15.41 20.41 19.58 26.26 4.41 6.71 13.08 17.73 16.35 18.76 19.67 26.65 24.87. 34.11 * Including areas at ceocnpaayiitf flangrs baited to tbs fitting. 458 CHAPTER 32 1959 Guide Pipe and Industrial Insulation 459 fig. 1 .... Heal Loss through 1 In. Thick Pipe Insulation (Ua trHh Tab)* 6 far VorioM bnfatbn) tivities of these two materials at mean temperatures of 8S5 and 3523 F, interpolated from Table 1, are 0.677 and 0.466 Btu, re spectively. These values are substituted in Equation 2 and a trial calcula tion made. The actual thickness of diatomaceous earth covering is 3395 in. and that of the 85 percent magnesia is 2.125 in. For a nominal 6-in. steel pipe: rt = 3312, r* -- 6.407, and r* -- 8332. Then, 6.407 __ 8332 833 + 524 8-S321g-^|8J321g-^ Hie temperature drop from the outer surface of the insulation to the surrounding air for a beat las of 783 Btu is found from Fig. 5 to be 493 deg for a 17-in. OD cylindrical surface, or 493 + 80 F room temperature ~ 1293 F surface temperature. Since a surface temperature of 135 F was assumed, it is evident that a temperature closer to 1293 F, or, for instance, 129 F should be used for recalculation: ' 1200 - 129 9* 833 + 534 783 Btu. Since the temperature drop through each material is egual to the heat flow times the actual resistance of each material, the temperature drop through the diatomaceous earth is 783 X fig. 2 .... Heat Loss through iH hu Thick Pipe Insulation (U wiifi Table 6 for Voriowi /Mufatitm*) 833 = 657 F, or the temperature between the two insulating materials is (1200 -- 657) = 543 F. Since a temperature of 570 F between the two materials was assumed, it is obvious that a temperature closer to 543, or for instance 545 F may be selected. The mean temperatures of the two insulations corresponding to the new assumptions are (1200 + 545) ^ 2 = 8723, and (545 + 129) r2 = 337, and the interpolated conductivities correspond ing to the new mean temperatures are 0375 and 0.461 for the diatomaceous earth and 85 percent magnesia, respectively. By substituting in Equation 2 1200 - 1291071 9* 5.63 78.5 Btu. 2.44 " 834 + 5.30 0.675 + 0.461 Again referring to Fig. 5, it is seen that the temperature drop from the outer surface of the insulation to the surrounding air for a heat loss of 783 Btu ~ 49 deg, which corresponds to the surface temperature of 129 F last assumed. The heat loss is therefore 783 X 8332 4- 3312 = 202 Btu per aq ft of pipe surface. Since the surface area per linear foot of 6-in. pipe is 1.734 sq ft (Table 2), the heat loss per linear foot of pipe will be 202 X 1.734 = 351 Btu per hr. The rate of heat loss from a surface maintained at constant temperature is greatly increased by air circulation over the surface. In the of well-insulated surfaces, the increases in losses due to air velocity are very small as compared with increases from bare surfaces, because of the fact that air fig. 4 .... Heat Loss through Insulation on fiat Vertical Surface (Use wifli Table 6 far Varioos insulations) fig. 3-------Heat Loss through 2 In. Thick Pipe Insulation (U*a wtffc ToMa 6 for Voriow tnakifiont) flowing over the surface of the insulation <*An increase only- the conductance of heat from surface to air, and cannot change the internal conductance of the insulation itself. The maximum increase in heat loss due to air velocity ranges from about 15 percent in the case of 1-in. thick insulation, to about 5 percent in the case of 3-in. thick insulation, provided that the insulation is thoroughly sealed so that air wn flow only over the surface. If the conditions are such that the air may circulate through cracks and crevices in the mcnlai.inn the increases may be far greater than those given. Therefore, it is essential that insulation be applied in such a manner that air circulation within it, or between it and the pipe, is avoided. Piping which is covered with a water-mixed product or insulation which will absorb moisture, particularly in damp locations, should be coated with a corrosion-resistant paint. ITiis precaution may prevent early failure due to external pipe corrosion. The frequent practice of omitting insulation on that por tion of a pipe which passes through a masonry wall, or which "ay be in contact with other metals, should be avoided. Physical contact between the pipe surface and other struc tural materials of high thermal conductivity will result in beat transfer much greater than that shown in Tables 2 and 3 for transfer from bare pipe to air. . The saving due to use of insulation on piping is illustrated in Example Example 4: If the steam pipe given in Example* 1 and t is covered with nominal 1 in. thick 85 percent magnesia, determine r"t*Iig tUl annual loss through the insulation. Also com pute the monetary value of the annual saving and the percentage of saving over the heat los from the bare pipe. " Solution: By referring to Fig. 1, the coefficient for 1-in. insula tion on a 2-in. pipe is found to be 0376 Btu per (hr) (linear ft of pipe) (deg temperature difference) at a temperature difference of 159.4 F. The heat insulation factor for 85 percent magnaoiii insulation, interpolated from Table 6, for a temperature differ ence of 159.4 F, is 1385. The total hourly loss per linear foot of pipe will then be 0276 X 159.4 X 1385 = 47.7 Btu. The total annual loss through the insulation = 477 X 165 (linear ft) X (4000 hr) = 31,480 Mb. The annual bare-pipe loss as determined iq the solution of Example 1 was found to be 171,100 Mb. The saving due to insulation is then 171,100 -- 31,480 = 139,620 Mb per year. From the solution of Example 3, it was found that the heat supplied to the system cost SO804 per 1000 Mb. Therefore, the monetary value of the saving -- 0804 (dollars) X 1398 (thousand Mb) -- $11223 or 8J6 percent of the cost when using nninp^infpH pipe. thickness of insulations to BE APPLIED Thermal insulation is used in a variety of thielmesHP^ for many varied reasons. Refrigerating equipment is normally designed for minimum heat gain, and heating equipment for minimum heat loss, within economical limits. This assures minimum-sized refrigeration or heating equipment, both from the standpoint of original as well as operational cost. Present refrigeration design practice limits the heat gain to 4 to 8 Btu per (hr) (sq ft) of exposed surface. Sometimes the principal object of the insulation is to limit the heat gain or loss to a specified value to control the temperature of a manu facturing or chemical process. Minor refrigeration and air-conditioning equipment and cold-water lines usually utilize only sufficient insulation thick ness to prevent condensation on the warm surface so as to prevent dripping. Occasionally the criterion for heated equip ment and pipes is the reduction of the outer surface to a tem perature (usually a maximum of 175 F to 200 F) low enough to prevent injury to personnel. ECONOMICAL THICKNESS OF INDUSTRIAL INSULATION The thicknesses of insulation which ordinarily are used for various temperature conditions are given in Table 7. Where a thorough analysis of economic thickness is desired, the thickness of insulation that will give the lowest sum of annual cost of heat loss and insulation may be found by of Fig. 6 ' As the thickness of insulation increases the annual 460 CHAPTER 32 1959 Guide Table 6 .... Heat Insulation Factors tor Various Insulations (To bo AppGed to fig*. 1, 2, 3, end 4) . Temperature Difference. Pipe to Air, F Deg 40 70 100 200 300 500 700 900 PIPE INSULA- TION ASBESTOS . Molded Amosite end Binder ' Laminated Asbestos Paper (35-40/in.) Corrugated and Laminated (4 ply/in.) Asbestos Paper (6 ply/in.) {8 piy/m.) CALCIUM SILICATE CELLULAR GLASS . CORK (No added binder) DIATOMACEOUS SILICA 22 lb DIATOMACEOUS SILICA 25 lb 85% MAGNESIA MINERAL WOOL (Rock. Slag, or Glass) Low Temp. (Asphalt or Resin Bonded) Low Temp. (Fine Fiber Rea. Bond) High Temp. (Metal Reinforced) PLASTICS (Foamed) - RUBBER (Foamed) WOOL FELT HAIR FELT OR HAIR FELT PLUS JUTE BLOCKS AND . BOARDS ASBESTOS MOLDED AMOSITE CALCIUM SILICATE CORKBOARD (Natural Binder) MINERAL WOOL (Low Temp.) MINERAL WOOL (High Temp.) MINERAL WOOL (Inorganic Binder) BLANKETS MINERAL WOOL (Felt Flexible Type) MINERAL WOOL (Felt Semi-Rigid Type) INSULAT- 85% MAGNESIA ING CE- MINERAL WOOL MENT 1.595 1.442 1.394 0.978 1.152 1.599 1.442 1.387 0.966 1.131 1.614 1.443 1.375 0.955 1.110 1.628 1.444 1.363 0.931 1.067 0.879 1.131 0.869 1.119 1.041 1.195 0.859 1.107 1.018 0.996 1.190 1.185 1.068 1.027 0.950 1.175 1.136 1.296 0.946 1.052 1.206 0.968 1.115 0.960 0.961 0.963 0.740 0.733 0.727 0.879 0.893 0.907 0.935 0.909 0.765 0.994 0.877 0.914 0.762 0.997 0.864 0.918 0.759 1.000 0.851 0.861 0.917 0.854 0.907 1.088 0.988 0.847 0.896 0.880 1.003 1.067 0.974 0.901 0.990 1.025 0.960 0.923 0.978 1.004 0.932 0.953 0.962 0.904 0.928 0.920 0.876 0.815 0.827 0.841 0.896 0.951 0.830 0.840 0.851 0.895 0.938 1.275 1.224 1.173 1.070 1.370 1.344 1.317 1.264 Pipe and Industrial Insulation 461 t-t/T' SCALE <r-tf [Ccnrat, Roofing, a.td Vanovs CoJored Ponded Surfaced fig. 5 .... Heat Loss from Canvas-Covered Cylindrical Surfaces of Various Diameters (From Reference 2 need by ponahdon. Not >o bo reprinted wifbotrf permitson) fig. 6 .... Chart for Determining Economical Thickness of Pipe Insulation 462 CHAPTER 32 1959 Guide Table 7 .... Thickness of Pipe Insulation . Ordinarily Used Indoors* Steam Prestore Psfg or Coafilioo Thickness of laudation Teaperotore FahntdteH Pipe* Larger Than 4 In. Pipes Pipes 2 In. to X* 4 in. to \X 0 to 25 25 to 100 100 to 200 . Low Superheat High Superheat 212 to 267 267 to 338 338 to 388 1 io. 1M m. 2 in. 1 in. 1 in. 1M m- 1 in. 1 in. 1 in. 388 to 500 2)4 in. 500 to 600 3 in. 600 to 700 3H in- 2 in. \)4 in. 2 in. 3 in. 2 in. All pipinc tented outdoors erexpceed to weather is ordinarily insclstod to in. greater than shown in table, and ntnd with a waterproof cost of heat loss decreases, but the annual cost of insulation (first cost multiplied by percent fixed charges) increases. The sum of the two costs will first decrease with increasing thick ness of insulating and then, depending on operating condi tions, will increase beyond a certain thickness. Therefore, the thickness at which the sum of the costs is a minimum, is the most economical. The method of n^ng the chart Fig. 6 is as follows: From the number of hours of operation per year at the bottom of the chart proceed upward to the line showing value of heat in dollars per million Btu using the appropriate scale A or B. Proceed right to temperature difference line using either scale A or B. Move upward to the line representing conductivity of the insulation being considered, then left to - discount line, upward to the percent fixed charge line, right to the pipe size or flat surface line and read the economic thir-lmwaa at top on the scale corresponding to the scales se lected for value of; heat' and temperature difference. For ex- Table 9 . . - Data for Estimating Requirements to Prevent Freezing of Water in Pipes with Surrounding Air at --18 F Nacsber of Hoars to Cool 42 Wafer to Fnoting Poart Nominal Pipe Size (lodwt) I Wafer Flow Roqauod fcf 42 F lo Prereat Fncz- I ing, Pound* por linoar I Foot of Pipe per Hour TMdcnes3 of insulation in Indies (Conductivity, k a 0J0| 2 3 4 23 4 X 1 IX 2 3 4 5 6 8 10 12 0.42 0.83 1.40 1.94 3.25 4.55 5.92 7.35 .10.05 13.00 15.80 0.50 1.02 1.74 2.48 4.27 0.57 1.16 . 2.02 2.90 5.08 0.54 0.68 0.84 0.95 1.24 0.45 0.55 0.68 0-75 0.94 0.40 0.48 0.58 0.64 0.79 6.02 7.96 9.88 13.90 18.10 22.20 7.20 9.69 12.20 17.25 22.70 28.10 1.47 1.73 1.98 2.46 2.96 3.43 1.11 1.29 1.46 1.78 2.12 2.45 0.93 1.06 1.19 1.43 1.70 1.93 ample; with Scale B heat value and Scale A temperature difference or vice Versa, use Scale A-B economic thickness. If the intersection with the flat surface is on the fiat surface continued curve, the economical thickness is read on the prime scales A'-A', A'-B', or B'-B'. . Cost of insulation refers to incremental cost in place; i.e., average incremental cost per unit thickness after the first unit. The first inch of insulation will usually cost more than each additional inch. This is due to cost of finish, contractor's 66tup, and operating costs, which do not increase in pro portion to thickness. The first inch of insulation, except in very unusual cases, provides enough saving in heat cost out of bare surface cost to more than cover these extra first costs. Table 8 .... Heat Gains for Insulated Cold Pipes Kate* of boot .(TQtmn&tMfl given m Bte per (baud (FaferecAerf degree temperature difference between Acrid to pipe and wruumfiifl (SO aid Based on materials having conductivity, k = 0.30 lo* Water Thickness . Brine Thickness Hoary Brine Thickness Pipe Site (indie*) Thickness of bwdatioa (Indies) Bte Per linear Foot Bte Per Sq Ft Pipe Thickness of Insulation (indies) Bte Per linear Foot Bte Per Slq Ft Pipe Ttudcness of Insulation (Indies) Btu Per linear Foot Bte Per Sq Ft Pipe Surface X 1.5 0.110 0.502 2.0 0.098 0.446 2.8 0.087 0.394 H 1.6 0.119 0.431 2.0 0.111 0.405 2.9 0.094 0.340 1 1.6 0.139 0.403 2.0 0.124 0.352 3-0 0.104 0.294 IK 1;6 0.155 0.357 2.4 0.131 0.300 3.1 0.113 0.260 *X 1.5 0.174 0.351 2.5 0.134 0.270 3.2 0.118 0.238 2 .1.5 0.200 0.322 2.5 0.151 0.244 3.3 0.134 0.214 2K 1.5 0.228 0.303 2.6 0.170 0.226 3.3 0.147 0.197 3 1.5 0.269 0.293 2.7 0.186 0.202 34 0.162 0.176 3H 1.5 0.295 0.282 2.9 0191 0.183 3.5 0.176 0.167 4 1.7 0.294 0.248 2.9 0.209 0.176 3.7 0.182 0.154 5 6 8 10 ' 12 1.7 0.349 0.239 3.0 0.241 0.165 3.9 0.202 0.138 1.7 0.404 0.233 3.0 0.259 0.150 4.0 0.228 0.130 1.9 0.455 0.201 3.0 0.318 0.140 4.0 0.263 0.116 1.9 0.559 0.198 3.0 0.383 0.135 4.0 0.309 0.110 1.9 0.648 0.194 3.0 0-438 0.131 4.0 0.364 0.108 Pipe and Industrial Insulation 463 To obtain discount from, insulation list price, first obtain applied prices for the desired type of insulation in one-inch, two-inch, etc., thickness. Then determine the average incre mental cost per inch above one-inch thickness. . Incremental cost in percent discount from list is "0-0 where X = average incremental cost in place per inch above one inch. y list price for one inch. ' In figuring pipe insulation, use the list price for one-inch thickness for a pipe size consistent with the average incre mental cost per inch. For example, if the average incre mental cost per inch is based on applied prices for one, two, and three inches, the incremental cost of the second and third inches would be averaged and the pipe size for list price would be that nearest the average pipe rise of the second and third inch. A rapid method for determining the economical of insulation by use of tables has been published.1 LOW TEMPERATURE PIPE INSULATION Surfaces maintained at temperatures lower than the sur rounding air are insulated to reduce the flow of heat and to prevent condensation. The insulating material should absorb a minimum amount of moisture, because the absorption of moisture substantially increases the conductivity of the ma terial. This property is particularly important in the insula tion of surfaces that are below the dew point of the surround ing air. In such cases, due to vapor-pressure difference, it is necessary to seal the surface of the insulating material against the penetration of water vapor which would condense within the material, causing a serious increase in heat flow, possible breakdown of the material, and corrosion of metal surfaces. An insulating material with a high degree of moisture absorp tion might pick up moisture before application and then, when the vapor seal is in place and the temperature of the insulated surface reduced, release that moisture to the cold surface. There are a number of methods of producing vapor seals, some of which have been worked out by insulation manufacturers to suit their products, and others by appiiers and users. Unless time-proven.methods are known, specifica tions of insulation manufacturers should be obtained and followed carefully. Equipment must be carefully protected against corrosion caused by condensation of water vapor. All metallic surfaces should be coated with a vapor-impervious barrier (some types of which have an asphaltic or tar base) without any breaks or openings in order to prevent corrosion. The thickness of insulation required to prevent condensa tion on the outer surface is that thickness which will raise the temperature of the outer surface of the insulation to a point slightly higher than the dew point of the surrounding vapor. The dew point for various humidities can be readily as certained from a peychrometric chart. The external vapor barrier must be made as nearly perfect as possible in order to prevent migration of vapor into the insulation. The approximate required thickness of insulation to pre vent condensation on pipes and flat metallic surfaces may be obtained from Jig. 7 in which a surface resistance of 0.606, corresponding to a film conductance of 1.65, was used in cal culating the curves. This value provides a slight factor of safety and its use is known to give satisfactory field results. In using the chart it is advisable to specify the next thicker, rather than the next thinner, commercial insulation in cases where an intermediate thickness is indicated. Heat gains for pipes insulated with a material having an installed conductivity of 0.30 Btu per (sq ft) (hr) (F deg per in.) are given in Table 8. This table may be used for any of the commercial insulations offered for this purpose since they have conductivities very near the 03 value used. INSULATION OF PIPES TO PREVENT FREEZING If the surrounding air temperature remains sufficiently low'for an ample period of time, insulation cannot prevent the freezing of still water, or of water flowing at such a veloc ity that the quantity of beat carried in the water is not sufficient to take care of the resulting heat losses that will cause the temperature of the water to be lowered to the freezing point. Insulation can materially prolong the time required for the water to give up its heat so that, if the velocity of the water flowing in the pipe is maintained at a sufficiently high rate, freezing may be prevented. Table 9 may be used for making estimates of the thickness 'of insulation necessary to take care of still water in pipes at various water and surrounding air temperature conditions. Because damage and service interruptions may result from frozen water in pipes, it is essential that an efficient insulation be utilized. This table is based on the use of a material having a conductivity of 030. The initial water temperature is as sumed to be 10 deg above, and the surrounding air tempera ture 50 deg below, the freezing point of water (temperature difference, 60 F). The last column of Table 9 gives the minimum quantity of water at initial temperature of 42 F that should be supplied every hour for each linear foot of pipe, in order to prevent the temperature of the water from being lowered to the freezing point. The weights given in this mlumn should be multiplied by the total length of the exposed pipe line ex pressed in feet. As an additional factor of safety, and in order to provide against temporary reductions in flow occasioned by reduced pressure, it is advisable to double the rates of flow listed in the table. It must be emphasized that the flow rates and periods of time designated apply only for the conditions stated. To estimate for other service conditions, the following method of procedure may be used. If water enters the pipe at any temperature other than 42 F, the time required to cool it to the freezing point will be equal to (t -- 32)/l0 times that given in the table, or the rate of flow of water may be changed to 10/(t -- 32) times the indicated flow rate in the last enlnmng of Table 9. How ever, if the water enters the pipe at 34 F, it will be cooled to 32 F in one-fifth of the time given in the table. It will then be necessary to increase the rate of flow so that five times the specified quantity of water will have to be supplied in order to prevent freezing. If the minimum air temperature is --38 F (temperature difference 80 F) instead of --18 F, the time required to cool the water to the freezing point will be 60/80 of the timn given in the table, or the necessary quantity of water to be supplied will be 80/60 of that given. In making calculations to arrive at the values given in Table 9, the loss of heat stored in the insulation, the effect of a varying temperature difference due to the cooling of pipe and water, and the resistance of the outer surface of the in sulation to the transfer of heat to the air, have all been ne- 464 CHAPTER 32 1959 Guide giected. mien these factors enter into the computations it is necessary to enlarge the factor of safety. Also as stated, the time shown in the table is that required to lower the water to the freezing point. A longer period would be required to freeze the water, but the danger point is reached when freez ing starts. The Sow of water will stop and the entire line will be in danger as soon as the water freezes across the section of the pipe at any point. If it is necessary to calculate the time required for the water to cool to 32 F, the following equation may be used H (3) . 171, + 32\ *LV~5~; 5. r* .log. u. f| (4) where . H = hours for water to cool to 32 F. ' r. = inside radius of pipe, inches. h -- initial water temperature. ' C, may be obtained from manufacturers' catalogs and hand books. See Equation 1 for definitions of other symbols. C9 ' Capacity of pipe, lb water/lin. ft = --~ X 62.4 When water must remain stationary longer than the times designated in Table 9, the only safe way to insure against freezing is to install a steam or hot water pipe parallel to the cold water pipe or to place an electric resistance heater along Rg. 7 .... Thickness of Pipe Insulation to Prevent Condensation on Outer Surface* Pipe and industrial Insulation 465 the side of the exposed water line. The heating system and the water line arc then insulated so that the heat losses from the heating system are not excessive, and the heating effect is concentrated against the water pipe where it is needed. Yot this form of protection 2 in. of an efficient insulation may be applied. APPLICATION OF INDUSTRIAL INSULATION Small pipes are normally insulated with half-sectional in sulation split horizontally and furnished with factory applied jackets forming hinge and lap. Large piping is insulated with segmental blocks, wired or banded in place, or with blanket insulations, particularly where removal for frequent servicing of the pipe is necessary. Indoors, sectional insulation is ap plied with the canvas lap pasted. Outdoors, it is necessary to provide a weatherproof finish. Fittings and bends are insu lated with portions of standard preformed insulation, blanket insulations, or insulating cements. Fitting insulation should be carefully specified to be compatible with the pipe insula tion. Insulation on lines carrying cold water, brine, or other cold fluids must be protected to prevent the infiltration of water vapor into the insulation. Flat, curved, and irregular surfaces such as boilers, breech-' ings, tanks, and vessels, are normally insulated with blocks or lagging, or with blanket forms of insulation. The insulation is secured in a variety of ways depending upon the form of insulation and contour of the surface to be insulated. One specification includes wiring the blocks in place, stretching a hexagonal mesh netting tightly over the insulation, and fastening securely with wires. Over the netting a coat of min eral wool or asbestos cement is applied with a second coat of asbestos cement trowelled to a smooth even finish. For out door installations weather protection is then applied. For insulation over surfaces at temperatures below ambient, water-vapor protection must be applied for both indoor or outdoor applications. "" The application of insulation to air-conditioning ducts is accomplished in a variety of ways depending largely on am bient conditions and temperature differentials between the air in the room and conditioned air. Boards or blankets arc normally used in a single layer 1 in. thick. Boards are fastened to the duct surfaces with spot or solid application of adhesive, and further reinforced with wires, bands, spindle anchors, or sheet-metal screws. Although,...where the service is not too severe, it is permissible merely to point the joints with a mastic compound, in most cases the insulations should be protected against water-vapor permeation. Where blankets are used the insulation can be wrapped around the duct, and held in place with tape over all joints or with spirally wrapped twine. Again in most cases the insulation should he provided with an outer vapor barrier protection. UNDERGROUND PIPE INSULATION . Underground steam distribution pipes may be installed in tunnels or in protective structures of various types, sizes, and shapes. Conduits for piping are described in Chapter 27. Pipes in tunnels are covered with sectional insulation to provide maximum thermal efficiency, and are also finished with good mechanical protection in the form of metal or waterproofing membrane outer jackets. In some instances, where actual submersion of hot lines may occur, it has been found good practice to fasten the covering securely with cor rosion-resistant wire, and then sew on a wire-inserted as bestos fabric jacket with wire. This jacket is porous. The Table 10 .... thickness of Loose insulation foi Ums . as Rll in Underground Conduit Systems Steam Pressure Psfg or Condition Fahrenheit Degrees Minimum Thkknets of Insulation in Indies Steam Lines Return Lines Minimum Distance Si I2 e <= W O a.H --c ?O o. Steam end Return Hot water, inor 0 to 25 212 to 267 IK 2 2K 25 to 125 267 to 352 2 2K 3 IK IK Above 125, or super- 352 to 500 2K 3 heat 3K lK IK 1 IK IK principle of withstanding submersion is that water may enter' - as water, then actually boil at the pipe surfaces and escape as steam without rupturing the insulation or jacket. Conduit systems are in more general use than tunnels. Pipes carried in conduits may be insulated with sectional insulation; how ever, the more usual practice is to fill the entire section of the conduit around the pipes with high quality, loose insula ting material. The insulation must be kept dry at all times, and for this purpose effective waterproofing membranes en close the insulation. A drainage system is also provided to divert water which may tend to enter the conduit. The economical thickness of insulation for underground work is difficult to determine accurately due to the many variables which have to be considered. As a result of theories1 previously developed, together with other experimental data which have been presented, the usual endeavor is to secure not less than 90 percent efficiency for underground piping. A comparison of heat loss under actual conditions vs. calculated values has been published by the National District Heating Association* Table 10 can be used as a guide in arriving at the minimum thickness of loose insulation fills to use for laying out conduit systems. Other factors such as the number of pipes and their combination of sizes, as well as the stand ard conduit sizes, are primary controlling factors in the amount and thickness of insulation for use. - When sectional insulation is applied to pipes in tunnels or conduits, usual practice is to apply the most efficient ma terials Vi in. less in thickness than that determined by the use of Fig. 6. The data in Fig. 6 are based on conditions of insulation exposed to the air, whereas normal ground tem perature is substituted for air temperature in determining the temperature difference for use with the chart when applying it for underground pipe system estimates. REFERENCES 1R. H. Heilman: Heat loss from copper piping (Heating, Piping and Air Conditioning, September 1933, p. 458). * Technical Data Sheet (Johns-Manville Corp., August 1955). * U. W. Smith: Rapid method of determining the economical thickness of pipe insulation (ASHVE Journal Section, Heating, Piping and Air Conditioning, October 1947, p. 118). * J. R. Allen: Theory of heat losses from pipes buried in the ground (ASHVE Transactions, Vol. 28, 1920, p. 335). * District Heating Handbook (National District Heating As sociation, 1951, 3rd ed, pp. 193-194). - 466 CHAPTER 32 1959 Guide BIBLIOGRAPHY F. C. Houghten and Carl Gutbertei: Heat emission from iron and copper pipe (ASHVE Transactions, Vol. 39, 1938, p. 97). Heat Transmission from Surfaces (Philip Carey Mfg. Co., Bulletin 102-A). R. H. Heilman: Surface heat transmission (Sec. 1, Mechanical Engineering, May 1929, p. 355). S. Crocker: Piping Handbook (McGraw-Hill Book Co., New York, 1945, 4th ed.). P. Swain: Insulation handbook (Power, Vol. 94, Nos. 2, 3, 5, 7, and 9,1950). U. W. Smith: How to insulate equipment (Plant Engineering, Vol. 1, December 1947, p. 32). T. S. Nickerson and G. M. Dusmberre: Heat transfer through thick insulation on cylindrical enclosures (ASMS Transactions, Vol. 70,1948, p. 903). H. J. Stoever: Applied Heat Transmission (McGraw-Hill Book Co., New York, 1941). CHAPTER 33 FUELS AND COMBUSTION Solid Fuels; Anofyris, Ckjwrficofron of Coals, Clossrfico/ion of Cokes, Combustion of Solid Fuels, Firing Methods for Solid Fuels, Secondary Air, Draft Requirements and Regulations, Furnace Volume; Fuel Oils; Classification, Air Required; fuel Cases: Oasdfkotron, Heal Value, Combustion; General Combustion Principles; Air Required; Efficiency from Flue Gas Analysis; Heat Balance; - Condensation and Corrosion; Soot; Air Supply to Furnace Rooms FUELS may be classified according to their physical when required in testing of heating devices. Typical ulti state as solid, liquid, or gaseous. The principal fuels mate analyses of the various kinds of coal are shown in used for domestic heating are coal, oil, and gas- However, Table 1* coke, wood, kerosine, sawdust, briquettes, and other sub Other important qualities of coals are the screen axes, stances are used for heating in special applications or in ash fusion temperature, friability, raking tendency, and the localities where an adequate supply is available. Experiments * qualities of the volatile matter. In considering these factors are in progress in the use of a colloidal suspension of coal . the following points are of interest. The volatile products particles in .fuel oil, but this fuel has not attained wide given off by coals when they are heated differ materially spread usage as yet. The choice of fuel is usually based on in the ratios by weight of the gases to the oils and tars. dependability, cleanliness, availability, economy, operating No heavy oils or tars are given off by anthracite, and very requirements, and control. small quantities are given off by semi-anthracite. As the SOLID FUELS volatile matter in the coal increases to as much as 40 per cent of ash and moisture-free coal, increasing amounts of Analysis of Fuels , oils and tare are released. For coals of higher volatile con tent, the relative quantity of mis and tars decreases and is Coal has a complex composition that makes classification therefore low in the sub-bituminous coals and in lignite. The into clear-cut types difficult. Chemically it consists of carbon, percentage of ash and its fusion temperature do not indicate hydrogen, oxygen, nitrogen, sulfur, and a mineral residue the composition or distribution of the constituents. called ash. A chemical analysis provides some indication of the quality of a coal, but does not define its burning' char Classification of Coals acteristics sufficiently. The coal user is interested princi pally in the available heat per pound of coal, the handling and storing properties, the amount of ash and dust produced, and the burning characteristics. A description of the qualities of coals and their characteristics can best be obtained from publications of the U. S. Bureau of Mines. A' treatment A classification of coals is given in Table 2, and a brief description of the kinds of fuel is given in the following paragraphs, but it should be recognised that there are no distinct lines of demarcation between the kinds, and that they graduate into each other. applicable to heating boilers is given in a U. S. Bureau of Mines bulletin.* ^ There are two types of coal analyses, namely, the proxi mate analysis and the ultimate analysis. In the proximate analysis the proportions of moisture, volatile matter, fixed Anthracite is a clean, dense, hard coal which creates little dust in handling. It is comparatively hard to ignite, but it bums freely when well started. It is non-caking, it bums uniformly and smokelessly with a short flame, and it re quires no attention to the fuel bed between firings.1 Standard anthracite suing specifications are shown in Table 3. carbon, sulfur, and ash are determined. This analysis is quite easily made and is satisfactory for indicating most of the characteristics which are of interest to the user. For the proximate analysis the moisture is determined by observing the loss of weight of a sample of coal when dried at about 220 F. To determine the volatile matter, the dried sample is heated to about 1750 F in a closed crucible, and the loss of weight is noted. The remaining sample is then burned in an open crucible, and the accompanying loss of weight represents the fixed carbon. The unbumed residue is ash. Although determined separately, the sulfur content is frequently reported with the proximate analysis because the usefulness of a coal for certain purposes depends on its sulfur content. In the ultimate analysis, which is difficult to make, the percentages of carbon, hydrogen, oxygen, nitrogen, sulfur, and ash in the coal sample are determined. It is used for detailed studies of fuels, and in computing a heat haJnnrp Semi-anthracite has a higher volatile content than anthracite. It is not so hard, and ignites somewhat more easily. Other wise their properties are similar. Semi-bituminous coal is soft and friable, and fines and dust are created by handling it. It ignites somewhat slowly and bums with a medium length of flame. Its tlring properties increase as the volatile matter increases, but the coke formed is relatively weak. Having only half the volatile matter con tent of the bituminous coals, it can be burned with less production of smoke, and is sometimes called a smokeless coal. Bituminous coal is a term covering a large range of coals and includes many types having distinctly different composi tion, properties, and burning characteristics. The coals ranee from the high-grade bituminous coals of the East to the poorer coals of the West. Their caking properties range from coals which melt completely, to those from which the volatiles and tars are distilled without change of form, so that they are classed as non-caking or free-burning. Most bitu minous coals are strong and non-friable enough to permit the screened sises being delivered free from fines. In general, they ignite easily and bum freely. The length of flame vanes with different coals, but it is long. Much smoke and / 467 448 CHAPTER 33 1959 Guide Table i.... typical Imtmaie Analyses for Coals 8te per Lb CoeifitMmfa, Percent Rank Mobi, MJneraJraotter- Moot, Receded Oxygen Hydrogen Carbon Nitrogen Sutfrr free* Anthracite...................................... 24,600 12,910 5.0 2.9 80.0 0.9 0.7 Semi-Anthracite............................ 16,200 13,770 5.0 3.9 80.4 1.1 1.1 Low-Volatile Bituminous............ 16,350 14,340 5.0 4.7 81.7 1.4 1.2 Medium-Volatile Bituminous-- 16,200 13,840 5.0 5.0 79.0 1.4 1.5 High-Volatile Bituminous A. ... 14,500 13,090 9.2 5.3 73.2 1.5 2.0 High-Volatile Bituminous B.... 13,500 12,130; 13.8 5.5 68.0 1.4 2.1 High-Volatile Bituminous C....... 12,000 10,750 21.0 5.8 60.6 1.1 2.1 Sub Bituminous B........................ 10,250 9,150 29.5 6.2 52.5 1.0 1-0 Sub Bituminous C........................ 9,000 8,940 35.8 6.5 46.7 0.8 0.6 lignite............................................. 7,500 6,900 44.0 6.9 40.1 0.7 1.0 (Bto u received) X 100 + (100 - 1.1 AM) A* O* + H, + C 10.6 8.5 6.0 8.1 8.8 9.2 9.4 9.8 9.6 7.3 87.9 89.3 91.4 89.0 87.7 87.3 87.4 88.2 89.0 91.0 legend: F.C Fixed Carbon. Cfoa Table 2 .. .. Classification of Coals by Rank* VJA. - Volatile Matter. Btu = British thermal anitx. . Group tiarft of Fixed Carbon or Bft* MineralMatter-Free Basil Regulate Pbydeol Properties I. Anthracite............... 1 III. Sub-bituminous-- 1. Meta-anthracite....... Dry F.C., 98 percent or more (Dry V.M., 2 percent or less) Dry F.C., 92 percent or more and less than 98 percent (Dry V.M:, 8 percent Non-agglomerating or less and more than 2 percent) 3. Semi-anthracite....... Dry F.C., 86 percent or more and less than 92 percent (Dry V.M., 14 percent or less and more than 8 percent) 1. Low volatile bitu- Dry F.C., 78 percent or more and less than 86 percent (Dry V.M., 22 per cent or less and more than 14 percent) 2. Medium volatile bi- Dry F.C., 69 percent or more and less than 78 percent (Dry V.M., 31 percent or less and more than 22 percent) Either agglomerating6 or non 3. High volatile A bi- Dry F.C., less than 69 percent (Dry weathering' V.M., more than 31 percent); and moist1 Btu, 14,000* or more 4, High volatile B bi- Moist* Btu, 13,000 or more and less than than 14,000* 5. High volatile C bi- Moist Btu, 11,000 or more and less than i3,000* 1. Sub-bituminous A Moist Btu, 11,000 or more and less than 13,000* 2. Sub-bituminous f Moist Btu, 9500 or more and less than Both weathering and non-agglom 11,000* erating6 3. Sub-bituminous C Moist Btu, 8300 or more and less than IV. liguitic.................... Moist Btu less than 8300 Unconsolidated - Adapted from A8TM Standard*, 1837, BuppUmml, p. US, Amwtcaa Sooety for Testing Material*. * tku does not mrinda lew eoela which have oaosoal physical and chemical properties and which cone within the limits of fixed carbon or fits of tha Myh.nltru'hifarTT'HwCT *11 *>-- nrmiaoiihitr aowialn la-- than 8 percent dry, mineral-matter-free fixed arbon, or have more than 15,600 moist, minend-matter-free Btu. . 6 11 agfhniwjating, ctamify in low-votatQe group of the bituminous class. . * Moist Bin r-'-ri to "|*l oonteunng its natural moiaturc but not unlading visible water on the surface of the coat. 4 It b recognised that there may be ooa^aldng varieties in each group of the bituminous data * fimh having 88 pwd or more fixed carbon on the dry, mineral-matter-free basis shall be classified according to fixed carbon, regardless of Btu. f There arc three varieties erf coal in the high-volatile C bituminous real group, namely. Variety 1, agglomerating and non-weathering; Variety t, agglomerating and weathering; Variety A non-aggfaxneiatiag and non-weathering. Fuels and Combustion 469 Tabie 3 .... Standard Anthracite SpecHkaHorw* Test Mesh Round Six* of Through hr. Coal Over in. Over tin Man % Udmin % Max MM MaxitmuB Impurities % 5 i 5% *< Broken.. 4H. 3H to 3 -- Era....... 3X to 3 2H 5' Stove.... 2Kfi m 7M Nut....... iH %> 7X Pea........ `Me k. 10 Buck- wheat... M. He 10 Rice. ... He Ht 10 Barley... He Hi 10 No. 4. .. Ht Ht 20 No. 5.. . H* 30 IS 7X ix 15 1H ix 15 7X 2 15- 7X 3 15 7M 4 15 7M 17 7M 20 10 30 10 No limit 2 2 3 4 5 11 11 n li 12 13 13 15 15 16 - Approved andadopted, effective July 38,1847, by the Anthracite Committee (Masutai *f Statisiietd Information, Anthracite Institute.) 6 When slate content in the sisee from Broken to Nut inclusive b less than above standards, bona content may be ioreekaed by one and one-half time* the decrease in the date cunteat under the allowable limits, but elate eontenl speci fied aboveshall not be exceeded in any event. Ash determinations are on a dry basil and include bona and ash. A tukranee of 1 percent b allowed on the percentage of ondersisa and the maximum percentage of sah content. Themaximum peroestageof onder- aisa b applicable only to anthracite aa it b produced at the preparation plant. Slate b defined as any material which baa leas than 40 percent of fixed carbon. Bone b defined at any materialwhich baa 40 percent or more, but lesa than 76 percent of fixed carbon. __ 'soot are possible, if improperly bred, especially at low rates of burning. Vv Sub-bitummtnu cools occur in the western states'^- they are high in moisture when mined and tend to break up as they dry or when exposed to the weather; they are'liable to ignite spontaneously when piled or stored. They ignite easily and quickly, and hare a medium length flame; are non-caking and free-burning; the lumps tend to break intosmall pieces if poked; very little smoke and soot are formed. Lignite is of woody structure, very high in moisture as mined, and of low heating value; it is clean to handle. It . has a greater tendency than the sub-bituminous' coals to disintegrate as it-dries, and it also is more liable to sponta neous ignition.' Freshly mined lignite, because of its high moisture, ignites slowly. It is non-caking. The char left after the moisture and volatile matter are driven off burns very easily, like charcoal. The lumps tend to break up in the fuel bed, and pieces of char falling into the ashpit continue to bum. Very little smoke or soot is formed. Gasstfication of Cokes . Coke is produced by the distillation of the volatile matter from coal. The type of coke depends on the coal or mixture of coals used, on the temperatures and time of distillation and, to some extent, on the type of retort or oven. Petroleum coke is produced as a residue from the destructive distillation of oil; COMBUSTION OF SOLID FUELS Firing Methods for Anthracite An anthracite fire should never be poked or disturbed, as this serves to bring ash to the surface of the fuel bed, where it may melt into clinker. Egg size is suitable for large fire-pots (grates 24 in. and over) if the fuel can be fired at least 16 in. deep. For best results this coal should be fired deeply. ' Stove is the proper size of anthracite for many boilers and furnaces. It burns well on grates at least 16 in. in diameter, on which it is fired about 12 in. deep. The fuel should be fired deeply and uniformly. Chestnut size coal is in demand for fire-pots up to 20 in in diameter, and is usually fired to a depth of from 10 to 15 in. Pea size coal is often an economical fuel to bum. When fired carefully, pea coal can be burned on standard grates. Care should be taken to shake the grates only until the first bright coals begin to fall through the grates. The fuel bed, after a new fire has been built, should be increased in thickness by the addition of small charges until it is at least level with the sill of the fire-door. A satisfactory method of firing pea coal consists of drawing the red coals toward the front end, and piling fresh fuel toward the back of the firebox. Pea size coal requires a strong draft, and therefore the best results generally will be obtained by keeping the choke damper open, and regulating solely by means of the cold-air check and the air-inlet damper. Buckwheat size coal, for best results, requires more at'tention than pea size coal, and in addition the smaller size of the fuel makes it more difficult to bum on ordinary grates. Greater care must be taken in shaking the grates than with the pea coal to prevent fuel from falling through the grate. In house heating furnaces, the coal should be fired lightly and more frequently than pea coal. When banking a buckwheat coal fire, it is advisable after coaling to expose a small spot of hot fire by putting a straight poker down through the bed of fresh coal. This will serve to ignite the gas that will be distilled from the fresh coal and prevent delayed ignition which, in some cases, depending upon the thickness of the bed of fresh coal, is severe enough to blow open the doors and dampers of the furnace. Where frequent attention can be given and care is exercised in manipulation of the grates, this fuel can be burned satisfactorily without the aid of any special equipment, except -small mesh grates. In general, it will be found more satisfactory with buck wheat coal to maintain a uniform heat output and, con sequently, to keep the system warm all the time, rather than to allow the system to cool off at times and then to attempt to bum the fuel at a high rate while wanning up. A uni form low fire will minimize the clinker formation and keep any clinker formed in an easily broken up condition so that it readily can be shaken through the grate. Forced draft and small mesh grates or, for greater convenience, domestic stokers are frequently used. Buckwheat anthracite No. 2, or rice size, is used princi pally in stokers of the domestic, commercial and industrial type. No. 3 buckwheat anthracite, or barley, has no ap plication in domestic heating. Firing Methods for Bituminous Coal A commonly recommended procedure for firing domestic heating units, called the side-bank method, requires the movement of live coals to one side or the back of the grate, and placing the fresh fuel charge on the opposite side. The results are a more uniform release of volatile gases, and the subjection of these gases to the high temperature of the red cods. If the fresh charge is covered with a layer of fine coal, still better results may be obtained because of slower release of volatile matter. . Bituminous coal should never be fired over the entire 470 CHAPTER 33 1959 Guide fuel bed at one time. A portion of the glowing fuel should firing door be kept closed, as the thinner fuel bed around the always be left exposed to ignite the gases leaving the fresh rides usually admits the required air. charge. The importance of filing bituminous coal in small quan Bring Methods for Coke tities at short intervals is discussed in a U. S. Bureau of Mines technical paper.1 Better combustion is obtained by Coke ignites les3 readily than bituminous coal and more readily than anthracite, and burns rapidly with little draft. this method in that the fuel supply is maintained more nearly In order to control the air admitted to the fuel it is very proportional to the air supply. important that all openings or leaks into the ashpit be closed If the coal is of the radring HnH, the fresh charge will tightly. A coke fire responds rapidly to the opening of the fuse into one solid mass that can be broken up with the dampers. This is an advantage in warming up the system, but stoking bar and leveled from 20 min to an hour after firing, . it also makes it necessary to watch the dampers more closely depending on the temperature of the firebox. Care should in order to prevent the fire from burning too rapidly. In be exercised when stoking not to bring the bar up to the surface of the fuel, as this will tend to bring ash into the order to obtain the same interval of attention as with other fuels, a deep fuel bed always should be maintained when high temperature zone at the top of the fire, where it will burning coke. The grates should be shaken only riightly in melt and form clinker. The stoking bar should be kept as near the grate as possible, and should be raised only enough mild weather, and should be shaken only until the first red particles drop from the grates in cold weather. The to break up the fuel. With fuels requiring stoking it may not best size of coke for general use, for small fire-pots where be neoessary to shake the grates, as the ash is usually dis the fuel depth is not over 20 in., is that which passes over lodged during stoking. It is acknowledged that it may be difficult to apply the outlined methods to domestic heating boilers of small rise, a I in. screen and through a 1Yt in. screen. For large firepots where the fuel can be fired over 20 in. deep, coke which passes over a 1 in. screen and through a 3 in. screen can be especially when frequent attendance is impracticable. The used, but a coke of uniform size is always more satisfactory. adherence to t-hewe methods insofar as practicable, how Large sizes of coke should either be mixed with fine sizes or ' ever, will result in better combustion. broken up before using. Preventing Smoke SECONDARY AIR In general, time, temperature and turbulence are the pRgpntiftJ requirements for smokeless combustion. Anything that can be done to increase any one of these factors will reduce the quantity of smoke discharged. Special care must be taken in hand-firing bituminous coals. In the case of new installations, the problem of smoke abatement can be solved by the selection of the proper fuel burning equipment and furnace design for the particular fuel to be burned, and by the proper operation of that equipment. Constant vigilance is necessary to make certain that the equipment is properly operated. In old installations the solution of the problem presents many difficulties, and may require a considerable investment in special apparatus. Lower rates of combustion per square foot of grate area will reduce the quantity of solid matter discharged from the chimney with the gases of combustion. The burning of coke, coking coal, and sized coal from which the extremely fine coal has been removed, will not, as a general rule, produce as much dust and cinders as will result from the burning of non-coking coals and slack coals when they are burned on a grate. Modern boiler installations are usually designed for high capacity per square foot of floor space, because such de signs give the lowest cost of construction per unit of capacity. Designs of this type discharge a large quantity of dust and cinders with the gases of combustion, and if pollution of the atmosphere is to be prevented, some type of dust and cinder catcher must be installed. When bituminous coal is hand-fired in a furnace, the volatile matter in the fuel is driven off by heat leaving coke on the grate. The product of combustion of the coke is CO* and under certain conditions some CO may arise from the bed. The combustion of the volatile matter and the CO may amount to the liberation of from 40 to 60 percent of the heat in the fuel in the combustion space over the fuel bed. The air that passes through the fuel bed is called primary air, and the air that is admitted over the fuel bed in order to bum the volatile matter and CO is called secondary air. This process of combustion is illustrated in Fig. 1.* The free oxygen of the air passes through the grate and the arii above it, and bums the carbon in the lower 3 or 4 in. of the fuel bed forming carbon dioxide. This layer noted as the oxidizing zone, is indicated by the symbols CO, and O,. Some of the carbon dioxide of the oxidizing zone is reduced to carbon monoxide in the upper layer of the fuel bed, noted as the reducing zone and .indicated by the symbols CO, and CO. The gases leaving the fuel bed are mainly carbon monoxide, carbon dioxide, nitrogen, and a small amount of free oxygen. Free oxygen is also admitted through the firing Firing Methods for Semi-Bituminous Coal The Pocahontas Operators' Association recommends the central cone method of firing, in winch the coal is heaped on the center of the bed to form a cone, the top of which should be level with the middle of the firing door. This allows the larger lumps to fall to the rides, while the fines remain in the center and are coked. The poking should be limited to breaking down the coke without stirring. Grates should be rocked gently. It is recommended that the slides in the Fuels and Combustion 471 door in an attempt to bum carbon monoxide, as well as the volatile combustible distilled from the freshly fired fuel. Size of the fuel is a very important factor in firing the quantity of secondary air required for non-caking coals. With making coals it is not so important, because small pieces fuse together and form large lumps. Fortunately, a smaller size fuel gives more resistance to air flow through the fuel bed, and thus automatically causes a larger draft above the fuel bed. More secondary air is drawn through the same riot openings, but, nevertheless, the smallest size of fuel will require the largest secondary air openings. For certain sizes of fuel, no secondary air openings are required, and for large sizes, too much excess air may pass through the fuel bed. In general, the efficiency of domestic hand-fired furnaces and boilers burning either anthracite or bituminous coal, can be increased for an hour or two after firing, if some sec ondary air. is admitted through riots of the fire door. How ever, unless the riots are closed when secondary air is no longer beneficial, the decrease in efficiency during the re mainder of the firing cycle, because of excess air, may more than offset the grin resulting from the secondary air at the beginning of the firing period. Unless the secondary air can be readjusted between firings, if is probable that a greater average efficiency will be obtained for domestic hand-fired devices by leaving the secondary air slots closed at all times. There is usually an appreciable amount of air leakage around the firing door and secondary air riots of domestic furnaces and boilers. , Draft Requirements for Coal and Coke Bring The draft required to effect a given Tate of burning the fuel is dependent on the following factors: (1) kind and size of fuel, (2) grate area, (3) thickness of fuel bed, (4) type and amount of ash and clinker accumulation, (5) amount of excess air present in the gases, (6) resistance offered by the boiler passes to the flow of the gases, and (7) accumulation of soot in the passes. Insufficient draft will necessitate additional manipulation of the fuel bed, and more frequent cleanings to keep its resistance down. Insufficient draft also restricts the con trol that can be accomplished by adjustment of the dampers. For draft requirements see Chapter 36. Draft Regulation for Coaljand Coke Bring Since heating load demands vary in most installations, it is necessary to vary the rate of fuel burning. The main tenance of the proper air supply for the various rates of burning is accomplished by regulation of the drafts. Methods of draft regulation used for solid fuel are shown in Fig. 2. Fig. 2 .... Methods of Draft Regulation in a Hand-Fired Furnace The air enters through the ashpit draft door, firing door, and by leakage through the setting, whereas the gases leave only through the outlet. By throttling flue gases with the damper in the outlet all the air entering by each of the three intakes is reduced in the same proportion, thus main taining about the same percent of excess air. If inlet air is controlled by the ashpit draft door, the air admitted through the ashpit is reduced, while it is increased through tire other two intake openings, resulting in an increase of excess air. A considerable increase in the efficiency of hand-fired fur naces and boilers can be realized by regulating the air sup ply by means of the damper in the outlet instead of the ashpit damper. Use of the ashpit damper is required, of course, for low rates of combustion. The cold air check damper is to be used only when chimney draft is excessive. It is normally closed unless the rate of combustion cannot be controlled by closing of the outlet and ashpit dampers. Furnace Volume for Coal and Coke The furnace volume is influenced by tbe kind of coal used. Bituminous coals, due to their long-flaming character istic, require more space in which to burn the gases of combustion completely than do the coals low in volatile matter. For burning high volatile coals, provision should be made for mixing the combustible gases thoroughly, so that combustion is complete before the gases come in contact with the relatively cool heating surfaces. An abrupt change in the direction of flow tends to mix the gases of combustion more thoroughly. Anthracite requires comparatively little combustion space. CLASSIFICATION OF FUEL OILS Fuel oils are mixtures of hydrocarbons derived from crude petroleum by refining processes. Crude oil is distilled in towers at atmospheric pressure to produce gasoline, naphtha, kerosine and gas oil, and leave straight-run residues. The straight-run residues are distilled under vacuum to produce heavy distillates. The vacuum-flashed residue remaining can then be thermally cracked to produce more gasoline, cracked naphtha, cracked distillates, and cracked residue. The exact processes used depend on the proportions of the various end products desired, and to some extent upon the compo sition and characteristics of the crude oil. Fuel oils may be designated as straight-run, thermallycracked, catalytically-cracked, or blended, depending on the refining process used to produce them. Straight-run fuels are those produced by distillation under atmospheric pressure without decomposition of the hydrocarbons by cracking. Thermally-cracked fuels are those produced by a cracking process involving elevated temperatures (850-1100 F) and pressures (300 prig) to decompose the heavier hydrocarbons. Catalytically-cracked fuels are those produced with the aid of an alumina-silica catalyst in the cracking process at lower pressures than those used for thermal crocking. Blended fuel oils are mixtures of any of the above three types. Grade GassHicafion of Fuel Oils Fuel oils are most commonly classified by dividing them into grades in accordance with the Commercial Standard (CS12-4S) entitled Fuel Od published by the U. S. Depart ment of Commerce. These specifications, given m Table 4, conform to ASTM Materials Specifications for Fuel Oils D 396 - 48. Table 4 also shows specifications for PS 300 and PS 400 fuel oils which are numbers used in the Pacific 472 CHAPTER 33 1959 Guide Grade of Awl OiIb Toble A .... Detailed Requirements for Fuel Oils* Haifa Point F Water 2crbon Poor Point F and Sed fteddue Adi iment on 10% % by % by Redd- Wt. Vol. wa % DirfiUafion Tem perature* F 10% 90% End Point Point Point Soyboff Vrtcodfy Second* Universal Fvtoi at 100 F of 122f Kinematic Yiscotity Cenfidoker ot 100 f at 122 F Min. Max. Max. Max. Max. Max. Max. Max. Max. Mfai. Max. MM. Max. MM. Max. MJ& 1. A distillate oil intended for va 100 0 Trace 0.15 420 625 porizing pot-type burners and or other burners requiring this Legal grade*1 API gravity 35 (min.) 2.2 1.4 2. A distillate oil for general pur . pose domestic heating for use in burners not requiring No. 1 API gravity 26 (min.) 100 or Legal 20* 0.10 0.35 675 40 (4.3) 4. An oil for burner installations 130 20 0.50 not equipped with preheating or . facilities Legal 0.10 125 45 (26.4) 5.8 5. A residual type oil for burner 130 installations equipped with pre or heating facilities Legal 1.00 0.10 150 40 32.1 (81) 6. An oil for use 'in burners 150 equipped with preheaters per or mitting a high viscosity fuel Legal 2.001 300 45 (638) (92) PS 300 . 150 or Legal 1.0 40 25 PS 400 150 2.O' 60 * BacoftnsiDC the neceraitjr tor Icnr aalfui tael oils used ia connection with heet-toeetment. nan-ferrous metel, ctatt end eelfor requirement may be specified as 0J% for No.' 1, 1-9% for No. S, and no limit for Noe. 4, 4 and & - Other etilfTTT liTwlte my epae4fit4 rtn\y Vry mn^.l teT---- ^Hr ^-y-T and SfllCT fumeces e&d other special uses, . b It la the intent of these chtsmfrrations that E&iluje to meet any requirement of a liven trade <kna not aatomatieaUy place an oil in the next lower grade unless in tact it meets all requirements of the lower grads. ' * Lower or higher pour points may be specified whenever required by conditions of storage or use. However, these specifications shall not require a pour point lower Qmw p p under any rendition. * 4 No. 1 <al shall pass test lor eccmkm made in accordance with paragraph 15 ASTU Specification* Jar PuM OiU, D 196-48. * The 10 percent point may be specified at 440 F maximum for use in otter than atomising burners. f The amount of water by distillation, plus (be sediment by extraction, shall not exceed J.flD percent. The amount of sediment by extraction, shall not exceed WO percent. A deduction in quantity shall be made for all water and sediment fa excess of 1.0 percent. . -. PS SOQand PSfOOarePadfio Specification numbers. Balance of table from Commercial Standard C8 IMS and ASTU Material* Specification for Pxul OiU DS96-4S. PS MO is a rrsidoal oil fee use without prebeating in furnaces and burners requiring a low viscosity fm>l, < eontmonly described as light fuel oil. domestic fuel oO, or tow viscosity fuel oil. . PS *00 is a residual ml far use in furnaces and burners equipped with preheaters permitting a high vfeanity fuel, and iwnmmiy described as industrial fuel oil, heavy fuel oil, or high viscosity fuel oil coast area. These oils correspond approximately to ASTM designations No. 5 and No. 6 respectively. Oils are classified by their viscosities. Other characteristics of fuel oils which determine their grade classification in the Commercial Standard, and their suitability for given uses are the flash point, pour point, water and sediment content, carbon residue, ash, and distillation characteristics. The flash point of an oil is important with regard to safety in handling and in storage. The distillation charac teristics determine whether or not the oil can be com pletely evaporated in some types of burners, and whether cracking will be likely to occur prior to combustion. A low pour point and low water content are necessary for handling and outdoor storage in cold climates. Sediment should be low to prevent clogging of strainers. Carbon residue is related to the rate of accumulation of unburned material in some types of burners. A low viscosity allows the fuel oil to flow through supply lines readily and to be broken up into small droplets in atomizing type burners. The sulfur content is of importance because undesirable compounds of sulfur may be formed in certain industrial processes. Some of these characteristics of a fuel oil are required to lie within certain limits for each of the grades of fuel oil listed in Commercial Standard CS12-48. Some fuel oils do not fall into any of the grade classifications of the Commercial Standard because failure to comply with all of the require Fuels and Combustion Table 5 .... Approximate Gravity and Calorific Value of Standard Grades of Fuel Oil Commercial Standard No. Approximate Gravity API Weight lb per gallon Colorific Value 8fv Per Gallon 1 38-45 6.951-6.675 137,000-132,900 2 30-40 7.296-6.870 141,800-135,800 4 12-32 8.212-7.206 153,300-140,600 5 8-20 8.448-7.778 155,900-148,100 6 6-18 8.571-7.882 157,300-149,400 ments of one grade does not automatically place the fuel oil in the next lower grade, unless it meets all of the require ments of the lower grade. By ultimate analysis the No. 1 and No. 2 fuel oils con tain 84 to 86 percent carbon, up to 1.0 percent sulfur, and the remainder predominantly hydrogen. The heavier grades of fuel oil, Nos. 4, 5 and 6, may contain as much as 88 percent carbon, as low as 11 per cent hydrogen, and con siderably more sulfur than is permissible in the domestic grades. Due to variation in the constituents of different fuel oils and the different refining methods used, the API gravities and calorific values of the different grades of fuel oil cover a range in each grade with some overlapping between do mestic grades and between commercial and industrial grades. API gravity, generally used when referring to specific gravity of oil, is obtained by the following formula in which the term specific gravity at 60/60 F indicates the ratio of tiie weight of a given volume of oil at 60 F to' ihe weight of the volume of water at 60 F: ' DetneS " specific 6075 P " "'5 The API gravity of water at 60 F is 10.0. The relation be tween the API gravity of fuel oils and their calorific value is shown in Table 5. Grades No. 1 and No. 2, which are distillates, are used predominantly in domestic heating equip ment whereas grades 5 and 6 are used in commericol and industrial burners. Grade 6 requires preheating to increase its fluidity and to permit atomization, whereas grade 5 may be used in some burners without preheating. Grade 4 fuel oil does not require preheating'and can even be burned satisfactorily in a limited number of domestic burners. Sources and Properties of Residual Fuel Oils Fuel oils Nos. 5 and 6 always contain residues remaining from the refining of crude oils. No. 4 oil will sometimes con sist entirely of heavy distillates but generally contains re sidual stocks. The residues may be classified, in accordance with their previous processing, as straight-run, vacuum-flashed, or cracked residues. Straight-run residues are the materials in crude oil that cannot be distilled at atmospheric pressure without appreciable decomposition and hence are removed as bottom fractions from crude topping units. These ma terials, often referred to as topped or reduced crude, are sometimes blended into fuel oil, but more frequently are processed, either by vacuum distillation or by thermal crack ing, to produce additional distillates. Residues from vacuum distillation processes are widely used as residual fuel blend ing stocks. Vacuum-flashed residues from some crudes must be subjected to a mild thermal cracking, known as viscosity 473 breaking, before they can profitably be blended, into fuel oils. Residues produced by thermal cracking of straightrun or vacuum-flashed residues or by thermal reforming of heavy naphthas, also are used in residual fuel oils. In processing reduced crudes and other stocks that yield residual fuel-blending stocks, the refiner evaluates the severity of treatment against, among other factors, the effect on certain properties of the residues. Perhaps the most sig nificant of these properties is viscosity. Maintenance of fuel viscosity within a certain range by preheating of tire oil is necessary to obtain satisfactory combustion efficiency with most burners for heavy oil. In most instances there is a maximum temperature to which the oil should be pre heated. Consequently a maximum viscosity is usually placed on the finished product. The second property of oil that is markedly sensitive to refining procedures is specific gravity. Residues may have gravities on either side of API 10, i.e., they may be either lighter or heavier than water. Since residual fuels in many ingtanrea are stored and used in the presence of water the densities of the fuel oils must differ sufficiently from water to assure their separation into distinct layers. The limits imposed by viscosity and specific gravity speci fications are met in part by refining practices and in part by Mending residues with distillates. These distillates may be straight-run gas oils and distillates produced by thermal or catalytic cracking. Blending of. residues and distillates generally entails down-grading of the latter. Consequently efforts are made to reduce to a minimum the quantities of cutter stock (the refinery term for distillates used for this purpose) necessary to meet manufacturing specifications. Heavy catalytically- or thermally-cracked distillates are generally used as cutter stock, not only because they are of less value for further processing than straight-run gas oils, but also because they have greater solvency for asphaltic ma terials in cracked residues. This discussion of residual fuel oils has been concerned principally with No. 6 fuel oil, the heaviest grade of residual fuel. Two other grades of residual fuels, Nos. 4 and 5, are pro duced and marketed. These fuels have lower viscosities and higher gravities than No. 6 fuel oil. Generally these specifi cations are met by increasing the ratio of cutter stock to residue, but occasionally these lighter fuels are made by blending No. 6 and No. 2 fuel oils. Sometimes No. 4 oil will consist entirely of heavy distillates but generally this grade of fuel contains residual stocks. Due to their higher distillate content both No. 4 and No. 5 grades bring higher prices than No. 6 fuel oil, and fre quently they are priced on a different basis, i.e., in centaper-gallon rather than dollars-per-barrel. Oil Burning Indexes A number of indexes have been used, or proposed, as an indication of the burning qualities of distillate fuel oils based on one or more physical measurements made on the oil. These may be summarized as follows: A. Indexes based on a single physical test: (1) API gravity,* (2) Aniline point* (3) Institute of Petroleum smoke test, (4) Carbon-Hydrogen ratio baaed on flue gas analysis or ultimate analysis, and (5) Percent aromatics determined by sulfuric add absorption tests* B. Indexes based on two or more physical tests: (1) Diesel index* based on API gravity and aniline point, (2) Institute of Petroleum cetane number* based on the API gravity and 50 percent distillation point, (3) Universal Oil Products char acterization factor* baaed on specific gravity and average 474 CHAPTER 33 1959 Guido boiling point, (4) Burning index1* based on API gravity and 50 percent distillation point, and (5) Estimated Carbon- Hydrogen ratio11 baaed on API gravity aniline point, and boiling point. - Various investigators have shown correlation between one or more of these indexes and the performance of fuel oils in oil burners. Experiments conducted with the Oil Heat Insti tute Reference Test Unit" indicated good correlation between the smoking tendency of fuel oils and API gravity, burning index, Diesel index, and hydrogen-carbon ratio for a limited number of oils in laboratory apparatus simulating a pressureatomizing burner. These results are shown graphically in Fig. 3. Smoking tendency is given here in terms of smoke-spot <Wi IMMCtoac* ter ttt ) UUlawte CO, a Per CM M UIIMel* CO, w MX tadttnw fefiactMc* although occasionally an oil is found that undergoes cracking at temperatures below 625 F. By the same criterion. No. 2 grade fuel oil in the Commercial Standard, which can have a maximum distillation temperature of 675 F at the 90 per cent point, would generally be cracked in a vaporizing burner. Vaporizing-type burners, therefore, can use only No. 1 fuel oil with assurance that thermal decomposition will not occur during combustion. On the other hand either No. 1 or No. 2 fuel oils may be employed in high- or low-pressure atomizing burners when the temperatures developed in the combustion chamber are high enough to assure complete combustion, even if the fuel oil is thermally decomposed. In vaporizing burners there is complete evaporation of fuel before it is exposed to intense heat. Thorough mixing of the air and gasified fuel promote complete combustion with out smoke and with a minimum of excess air. In pressuretype burners good atomization of the fuel, good muring of the atomized oil with the air, air turbulence, and high com bustion chamber temperatures (preferably red hot) promote smokeless combustion with a minimum of exces air. Natural draft burners depend on the motivating force of a chimney to induce enough air into the burner for complete combustion. Forced draft burners are supplied with com bustion air by means of a blower or fan; the chimney merely conducts the flue gases outdoors and prevents leakage of flue gases into the building. More details on the operation of the different kinds of oil burners and on chimneys and draft will be found in Chapters 34 and 36 respectively. FUEL GASES fig. 3 .... Correlation of Burning Qualities of Fuel Otis with Four Combustion Indexes reflectance, the light reflectance of a smoke-soiled filter paper. A high reflectance, relative to aclean filter paper, indicates low smoking tendency. C0*/C7 is the observed CO. divided by the ultimate or maximum theoretical CO, expressed as a percentage. Reid and Hersberger1* have related burning qualities and burning index for various oils in a wall-flame burner. Cauley and Delgass" cite test results on combustion indexes obtained with vaporizing burners. The present ex perimental data are probably too meager as yet to correlate adequately any one of these indexes with burning qualities of oil fuel for all types of burners. Few attempts have been made to suggest limits,for any of these fuel oil indexes for particular applications, even though correlations between them and burning qualities have been observed. Experiments have shown that the rate of thermal decom position or cracking of hydrocarbons becomes appreciable at a temperature of approximately 680 F at atmospheric pres sure. Thus distillate fuel oils, whose end point approximates this temperature, cannot be completely evaporated in vapor izing-type oil burners at atmospheric pressure without leav ing a residue. A complete distillation curve cannot usually be determined for fuel oils containing fractions that evaporate above 680 F. ' Since No. I grade fuel oil in Commercial Standard CS12-48 has a maximum end point of 625 Ft although an end point this high is rare, it can in most cases be completely evapo rated in atmospheric vaporizing burners without cracking, Fuel gases employed for various heating and air condition ing processes throughout the United States fall into three broad classifications: natural, manufactured, and liquefied petroleum. Natural gas is a mixture of several combustible gases and, usually, a small percentage of inert gases obtained from geologic formations. Manufactured gas is made by the distillation or cracking of oil or coal, by the steam-carbon reaction, or by combinations of these processes. Liquefiedpetroleum gases (propane and butane) are higher hydrocar bon gases normally obtained as a by-product of oil refineries or by stripping natural gas. These two compounds are gen erally gaseous under usual atmospheric conditions although they can be liquefied by the application of moderate pres sures at normal temperatures. In American gas practice the halting value of a gas and also appliance efficiencies are based on the gross beating value. This value is the number of Btu liberated by complete combustion, at constant pressure, of one cubic foot of gas saturated with water vapor and measured at 60 F and 30 in. of mercury, with air at the same temperature and pressure. Products of combustion are cooled to the initial temperature - of the gas and air and the water formed by combustion of free and combined hydrogen is condensed to the liquid state. Classification of Gases Representative properties of gaseous fuels commonly em ployed for domestic heating processes are shown in Table 6."- " Natural gas contains from 55 to 98 percent methane with various percentages of higher hydrocarbons, chiefly ethane. In addition to these, components, small quantities of non combustible gases such as carbon dioxide, nitrogen, and he lium are sometimes present. Percentages of the different components vary with the area from which natural gas is withdrawn. They may even vary slightly from any given well Fuels and Combustion 475 . No. Typo Table 6 .... Typical Cos Analyses Consfilumiti of Gas--Percent by Volume CO, o, N, CP H, ch4 C*H( C*H, C<H Spe Btu par cific Co Ft* flr4 Gna Net 1 Natural gas...................... Typical 3 Propane............................. Commercial (refinery gas) Commercial (refinery gas) 7 Reformed natural...----8 Refinery oil...................... 9 Oil gas............................... 10 Coal gas............................ 11 Coke oven gas................. Straight shot generator Vapor phase crack Portland, Ore. Contin, Vert. . By-product Bituminous ' 14 Blue gas............................ 15 Carburetted water gas... 16 Carburetted water gas... 17 Mixed Gas........................ 18 Mixed Gas........................ Bituminous Heavy oil with blow run High Btu Natural, Blue, Producer, Reformed Natural Coal, Natural 0.8 83.4 15.8 0.61 1129 1021 2.2 1.55 2558 2358 2.0 72.9 0.8 C*H, 24.3 1.77 2504 2316 6.0 2.04 3210 2961 66.7** CH* 28.3 2.00 3184 2935 17.2 Air 82.8 1.16 550 516 (Illumin&nts) 2.1 10.3 1.5 13.6 48.3 33.0 1.2 0.41 559 497 0.2 9.2 0.5 1.2 13.1 23.3 21.9 39.6 0.89 1475 1351 1.2 9.5 2.4 7.7 54.2 30.1 3.9 0-37 570 510 3.0 9.2 4.4 10.9 54.5 24.2 2.8 0.42 532 477 2.0 0.03 4.8 5.5 51.9 32.3 3.2 0-40 569 509 27.0 14. C 0.86 163 153 27.5 1.0 1.02 92 92 5.5 0.9 27.6 28.2 32.5 4.6 0.7 0-70 260 239 6.0 0.9 12.4 26.8 32.2 13.5 8.2 0.66 530 451 0.7 0.3 5:8 11.7 28.0 36.1 17.4 3.9 0.1 15.5 10.3 17.8 46.9 54 0.1 0.63 840 770 0.63 650 586 1.1 9.4 6.6 4.0 35.8 45.7 4.6 III. 0.46 700 627 19 Mixed Gas........................ Natural, Coke Oven 1.0 9.2 5.5 2.0 20.9 66.6 2.6 111. 0.52 802 721 20 Sewage Gas...................... Decatur, 111. 22.0 6.0 2.0)68.0 0.79 690 621 This table abstracted from Gateeto Pm*U, Americas GarAeecciatioa. aad from A.G.A. Laboratories Data. * At SO F isd SO in. mereary, absolute pressure. ** Divided 1SA% ieobutane, SO.1% n-botasc. Divided taobutaae, 70.7% a-butaoe. during its lifetime but these variations are inconsequential insofar as the utilization of the gas is concerned. Heating values of natural gases vary from 900 to 1400 Btu per cu ft but the usual range for use is from 1000 to 1050 Btu (gross) per cu ft. A typical analysis is given in Table 6- Manufactured gases commonly produced are listed' in Table 6. Gross, or higher, calorific values of typical send-out gases made from these manufactured gases generally range from 500 to 600 Btu per cu ft. Due largely to the greatly increased demand for city gases the tendency during recent years has been to increase rather than to decrease heat con tent of manufactured gases, thus making it posable to serve more customers through the existing distribution system. Mixed,gases are a result of increased distribution of natu ral gas, through transcontinental transmission lines, into areas having existing manufactured gas facilities. In such in stances some gas companies supply a 600 to 800 Btu mixture (see Table 6). In some territories these mixtures are dis tributed as an intermediate step in changing over from manufactured gas to natural gas. Although the burden of adjusting installed heating and air-conditioning equipment and supplying new orifices and burner equipment is gen erally assumed by the gas companies when the gas is changed, it is advisable to consult the local gas company to insure that equipment is provided with proper orifices and burners when installed. Most states enforce legislation through their public serv ice. commissions to require delivery of a gas of specified average or minimum heating value within their respective . limits. Any given heating value within reason fortunately may be maintained and yet permit considerable latitude in the composition of the gas distributed. Hence the constitu ents of city gases are not necessarily the same in different districts nor even at successive stations in the same district. In every community, however, the objective is to maintain variations in composition and gas pressure within limits that will provide satisfactory operation and performance of all common types of gas burning equipment. Liquefied petroleum gases, such as propane and butane or mixtures thereof have calorific values ranging from 2500 to 3200 Btu per cu ft. These fuels are often supplied as liq uids under pressure in tanks or bottles. In such cases the liquid evaporates when pressure is relieved, the heat neces sary for vaporization being obtained from the surrounding air or ground. As butane boils at 32 F some provision is necessary for maintaining the gas above this temperature or for lowering the partial pressure by dilution if the gas is utilized in colder climates. Propane, with a boiling point of --40 F, may be served in* localities where temperatures sub stantially below freezing are encountered. When employed for heating purposes, these gases are usually stored in high pressure tanks and delivered by tank truck in much the same manner as fuel oil. Both ga9es, mixed with air, or in undiluted form, are also extensively employed by gas com panies to augment their base load supplies during peak load periods. In some smaller communities, where gas manufac turing plants are not economically feasible and natural gas is unavailable, liquefied petroleum gases or liquefied petro leum gas-air mixtures are supplied through mains in much the 6am|> manner as manufactured or natural gas. 476 CHAPTER 33 1959 Guide COMBUSTION OP GASEOUS FOBS Gas burners employed in domestic beating appliances are generally of the son-luminous flame or Busses type. Part of the air required for combustion is inspirated as primary air into the burner mixing tube where it nriTwa with gas, and then takes part in combustion at the burner ports. As the amount of primary air is seldom sufficient to support com plete combustion, additional air is supplied to the burner flames around the periphery of its ports. Tins secondary air is induced into the appliance and around the base of each separate burner flame by force of the issuing mixture of gas and primary air and by draft inspiration inherent in the heat of the flames. If a Bunsen type burner is properly ad justed, its flames will generally have a clear, blue appear ance. Yellow are indicative of insufficient primary air supply, and possibly of incomplete combustion. An ap preciable updraft is seldom, if ever, present even in flue- connected gas heating appliances, because most appliances of this Hnd are equipped with a draft hood winch reduces the chimney draft at the appliance. It is important to note that gas furnaces and boilers, as well as most other classes of heating equipment, are designed to create their own draft. The air-to-gas ratio in a Bunsen burner head has a de cided eSect on the rate of flame propagation. The gas-air mixture must flow from the burner ports faster than the flame bums, otherwise flashback will occur. The flashback condition normally results either from an excess amount of primary air or insufficient gas or both. Conversely, the veloc ity of the issuing mixture must not be so high that the flame will be blown from the ports, a condition known as lifting. Fortunately, contemporary types of such burners have a rather wide range of flexibility in capacity and ad justment. In addition to tim characteristic, gas supply is normally so uniform that if a gas heating appliance is prop erty adjusted when it is installed, its burners, with occa sional cleaning, should provide trouble-free service for years. When problems incident to changeover of the gas supply are involved, they are generally assumed by the local utility' providing the supply of gas. In many instances when.the gas supply is changed, it is necessary .to change the burn ers to those suitable to bum the new kind of gas. It should be recognized that a change in fuel gas will change the operating CO, value. For example, an appliance operating on carburetted water gas at 20 percent excess air will have 14J2 percent CO, in the flue gases. If a change is made to coke oven gas at the same gas input rate, with the excess air maintained at 20 percent, the operating CO, would drop to 92 percent. Luminous flame burners are occasionally used in central heating gas appliances. With these devices all air required for complete combustion is supplied to the flames as second ary air. Two fundamental advantages of this type of burner are that the possibilities of flashback are eliminated, and that a much higher gas velocity is needed to blow the flames off the ports. On the other hand, if there is any appreciable amount of flamfi impingement on any portion of the heating surface, or if secondary air is not effectively supplied to the flames, soot may be formed and also combustion may be incomplete. . In some types of gas burners radiant baffles are used to convert part of the energy formed during the process of combustion to radiant heat. These baffles may also, serve to direct the flow of products of combustion along the heat absorbing surface. Gas-designed furnaces and boilers approved by the Ameri can Gas Association are certified for operation at the rating shown on the nameplate. Considerations relating to safety, performance, and service life, require that such appliances be adjusted at inputs that do not exceed the nameplate in put rating. These appliances normally draw in from 20 to 50 percent excess air, depending on the type and general de sign. As has been indicated, some excess air is necessary to insure complete combustion at all times and also to pro vide a reasonable degree of flexibility in performance. Various types of appliances used for gas space heating purposes are described in Chapter 34. FUNDAMENTAL PRINCIPLES OF COMBUSTION Regardless of the type of fuel under consideration, its combustion results in the production of gaseous products. Many kinds of solid fuels contain minerals which cannot be burned and are therefore left as a residue commonly called afih. Moreover, unless sufficiently high temperatures are em ployed and an ample supply of oxygen properly distributed is present, the combustible constituents of solid, liquid, and even gaseous fuels cannot be completely burned. Incomplete or partial combustion of all fuels produces toxic gases, such as carbon monoxide, with smaller quantities of aldehydes, ' Anthracite - M 03 ' fin* Gas Teejperotere Shown, leu it Sated 00 65 F Room Temperature Fig. 4 .... Flue-Gas Losses with Various Fuels* Fuels and Combustion ketones, and other hydroxylated hydrocarbon compounds. This fact indicates that, white combustion processes involv ing common types of fuel may be regulated by experienced operators to produoe the most efficient results, normal com bustion processes can be so unbalanced as to create hazards unless both design and operation are planned with a knowl edge of the fundamental principles of combustion. Combustion may be defined as tbe chemical combination of a substance with oxygen resulting in the evolution of heat, and usually same light. The rate of combustion depends upon the rate of reaction of the substance with oxygen, upon the rate at which oxygen is supplied, and upon the tempera ture obtained due to surrounding conditions.- This is com bustion in its simplest form. All solid, as well as liquid and even gaseous fuels generally contain several combustible elements in combination with others which, depending on their nature, affect oxygen requirements and thus govern the combustion process. For a continuous reaction, as in heating processes, it is necessary to establish an effective balance between rates of removing heat and of supplying fuel and air-or oxygen to keep the reaction going. In estab lishing such a balance, conaderation must be given to the removal or venting of products of combustion, so that the 477 entire process is one of flow wherein draft conditions in the combustion space are important. Complete combustion is obtained when all combustihle elements in a fuel are oxidized by all of the oxygen with which they will combine. All oxygen or air supplied is gen erally not utilized, and this excess portion is commonly referred to as excess oxygen or excess air. Excess air is usu ally expressed as a percentage of the air required for per fect combustion. Perfect combustion results when the exact amount of oxygen required for complete combustion of all elements of a fuel is supplied and utilized. Tbe percentage of carbon dioxide contained in the products of combustion from such a reaction is obviously the maximum attainable and is re ferred to as the ultimate CO, or maximum theoretical per centage of carbon dioxide. This condition of perfect com bustion, without having excess air or oxygen left from the reaction, is seldom, if ever, realized in practice. Most types of besting equipment must be sufficiently flexible in per formance to provide complete combustion with not only variations in tbe quality of a fuel but also changes in the rate at which rt is supplied. This situation makes it advis able, from a practical standpoint, to insure complete com- ZC02 Z EXCESS AIR IN FLUE GASES ZEXCESS AIR XC02 IN FLUE GASES 5O0_ -*00_ Us! X FLUE LOSS BUTANE AND PROPANE 5jso4- Z FLUE LOSS -5 r Adopted from American Gat Association laboratories floe lass Charts. Fig. 5____ Alignment Chert for Calculation of Rue losses for Butane, Propane, Coke Oven, and. Natural Gases 478 CHAPTER 33 1959 Guide Table 7 .... General Data of Combustible Elements and Compounds Subrtonce Carbon (to CO) Carbon (to CO,) Sulfur (to SO,) Sulfur (to SO,) Carbon Monoxide Methane Acetylene Ethylene . Ethane Hydrogen Hydrogen Sulfide Propane n-Butane Commercial Propane Commercial Butane Motecufar Symbol Chemical Reaction of Combutfioti _ -- -- -- CO CB, CtB, CtH* CtH. Ht HtS C*H, V*Uu -- -- 2C -f O, - 2CO 2C + 20* - 2CO, 5 + 0,- SO* 25 +- 30, - 250, 200 +- 0, - 2CO, CB* +- 20, = CO, +- IBtO 2CtHt + 50, - 4CO, +- 2BtO CtH* +- 30, = 2CO, +- 2B,0 2CtH* + 70, - 4CO, + 6BgO 2H, + 0,= 2BtO 2H*S +- 30, = 2HfO + 250, C*H* + 50,=* 3C0, +- iBtO 2C*Bi* +- 130, =* SCO, +- lOBtO -- -- fgnttiM letup*, ufurs* F Oeg Calorific Value theoretical Oxygen and Air Requirement Bhi per Lb Btu par Cu Ft* lb per Lb Cu Ft per Cu Ft Gras* Nef Gras, O, Air o. Air __ __ _ __ 1166-1319 1260-1380 763-824 986-1123 990-1120 1063-1166 599-608 950-1080 890-1020 920-1020 900-1000 3950 14093 3983 5940 4347 23879 21500 21644 22320 60958* 7100 21661 21308 21560 21180 __ . __ _ 21520 20776 20295 20432 51571* 6545 19944 19680 19865 19591 1.33 5.76 __ 2.66 11.53 __ __ __ 1.00 4.29 __ __ _ 1.50 6.43 __ __ 321.8 3.57 2.47 0.5 2.39 1013.2 3.99 17.27 2.d 9.53 1499 3.07 13.30 .2.5 11.91 1613.8 3.42 14.81 3.0 14.29 1792 3.73 16.12 3.5 16.68 325 7.94 ^4.34 0.5 2.39 647 1.41 6.10 1.6 7.15 2590 3.63 15.70 5.0 23.82 3370 3.58 15.49 6.5 30.97 2520 3.60 15.58 4.9 23.4 3260 3.54 15.3 6.3 30.0 Vthx* in table taken chiefly from pace M of Pud Flu* Gate* published by Aiwricu Gas fc Gm iiieaauiud at 60 F and SO in. He- * Value from National Bureau of Standard*. bustion but not perfect combustion in the sense, expressed above. To attempt to do so would undoubtedly result eventu ally in unsatisfactory performance especially from a safety standpoint. Consequently, common types of heating equip ment are usually designed, installed, and adjusted to operate with some excess air. The exact percentage of such air de pends on the type of fuel being utilized, as well as antici pated variations in its quantity and quality. Despite these practical limitations, however, it should not be inferred that common types of fuels cannot be utilized economically. Ref erence to flue loss charts such as Figs. 4 and 5 for gas burn ing equipment and to the air requirements discussion in Chapter 34 shows that reasonable quantities of excess air can be used without appreciable reductions in operating efficiencies. . Oxygen combines with the combustible elements and com pounds of. any fuel in accordance with fixed laws. The reac tions and resultant products of .perfect combustion of com mon fuel constituents are shown in Table 7. All of the oxygen required for combustion is normally obtained from the surrounding air, which is a mechanical mixture of nitro gen and oxygen with small amounts of carbon dioxide, water vapor and inert gases. For practical combustion calcula tions, air is considered to consist of 20.9 percent oxygen and 79.1 percent nitrogen by volume, or 23.15 percent oxygen and 76.85 percent nitrogen by weight. The nitrogen, being inert, passes through the reaction without change. Table 7 gives tiie air quantities corresponding to the oxygen required for perfect combustion. * Air supplied to the combustion reaction is in most in stances introduced in two ways. Primary air is introduced through or with the fuel, and secondary air is supplied to the flames issuing from the fuel. Incomplete combustion is obtained when any of the com bustible elements are not completely oxidized in the combus tion reaction. This condition not only represents inefficient use of the fuel but also presents a hazard because carbon monoxide is usually one of the products of incomplete com bustion. For example, a hydrocarbon may not oxidize com pletely to carbon dioxide and water, as indicated in Table 7, but may also form alcohols, ketones, aldehydes, or carbon monoxide depending on where and how the reaction is in terrupted. Too low a temperature (such as may be caused by flame impingement on a cold surface), a poor oxygen supply to the flames (due to insufficient or poorly located air supply, or smothering by products of combustion not properly vented), or insufficient mixing of the air and fuel, are the primary causes of incomplete combustion. Heat of Combustion As previously stated, the process of combustion results in the evolution of heat. The heat generated by the com plete combustion of a unit of fuel is constant for a given combination of combustible elements and compounds, and is known as the heat of combustion, colorific value, or heat ing value of the fuel. The heat of combustion of the several substances found in the more common fuels is given in Table 7. The calorific value of a fuel may be determined either by direct measurement of the heat evolved during combustion in a calorimeter, or it may be computed from the ultimate analysis and the heat of combustion of the several rlwmiMil elements in the fuel. When the heating value of a fuel is determined in a calorimeter, the water vapor is condensed and the latent heat of vaporization is included in the Hunting value of the fuel. The heating value so determined is termed the gross or higher heating value, and thia is what is ordi narily meant when the heating value of a fuel is specified. In burning the fuel, however, since the products of combus tion are not cooled to the dew-point and the higher hoofing value cannot be utilized. , When combustion is complete, the carbon in the fuel unites with oxygen to form carbon dioxide, CO*, the hydro gen unites with oxygen to form water vapor, HJO, and the nitrogen, being inert, passes through the reaction without change. When combustion is incomplete, some of the carbon may unite with oxygen to form carbon monoxide, CO, and some of the hydrogen and hydrocarbon gases may not be Fuels and Combustion 479 burned at all. When carbon monoxide or other combustible gases are present in the flue gases, there i3 a loss of heat produced per unit of fuel consumed, and consequently, a lower combustion efficiency is obtained. Incomplete combus tion may result from any or all of the following three condi tions: (1) inadequate air supply, (2) insufficient mixing of air and gases, and (3) a temperature too low to produce ignition or maintain combustion. AIR REQUIRED FOR PERFECT COMBUSTION Air requirements for combustion of solid and liquid fuels are ordinarily expressed in pounds. On the other hand simi lar requirements for gaseous fuels are usually stated on a cubic foot basis. For solid and gaseous fuels this method of treatment corresponds to the standards of measurement commonly employed by these two industries. The weight of air required for perfect combustion per pound of solid or liquid fuel may be calculated after substi tution of the proper percentages by weight of the various elements obtained from an ultimate analysis of the fuel in Equation 2. For gaseous fuels see Equation 3 for volume of air required. Solid or Liquid Fuels: Pounds air required per pound fuel For Gaseous Fuels: Cubic feet air required per cubic foot gas '" = 2.39 (CO + Ht) + 9.53 CB* + 16.68 C*H% +- 23.82 CH, + 3057 CJTt. + 11.91 C*B, + 1459 CtH* + 7.15 - 4.78 O, +- 30.47 Illuminants (3) Gaseous fuels may contain a wide variety of components classified as Uluminants, which are not separated by the qml methods of gas analysis. The principal illuminants in addition to ethylene (C*H*) and acetylene (C*Ht) which are included in Equation 3, with the air required per cubic foot of gas are: propylene, 21.44; butylene, 28.58; pentene, 35.73; benzene, 35.73; toluene, .42.88; and xylene, 50.02. Since toluene and xylene are normally scrubbed from the gas before distribution, they may be disregarded in computing air required for a fuel gas. An approximate value of 30.47 (as shown In Equation 3) may, .therefore, be employed. If ethylene and acetylene are included as illuminants, it is sug gested that the value 19.65 be used. If it is desired to make the gas calculations on a weight basis the equation is expressed as follows: Pounds air required per pound fuel - 2.47 CO + 3454 Bt + 1757 CB, +- 16.12 CtH* + 15.70 CtH* + 15.49 CJh* + 13.30 C*B* + 1451 CtH* + 6.10 B*S - 452 O, (4) Where approximate results only are desired, values ap pearing in Table 8 may be substituted for Equations 2, 3, and 4; or the air required for perfect combustion may be estimated by assuming that 0.9 cu ft air is required per 100 Btu of fuel. ` Where extreme precision is involved it is suggested that the reader refer to scientific literature published on the sub ject of combustion and related topics by the various indus tries concerned. If approximate values for theoretical air requirements suffice, or if complete information on the fuel is not available, the following values should also be found helpful: I. Solid Fuels (Pounds air per pound fuel): Anthracite, 95; Semi-Bituminous, 115; Bituminous 103; lignite 63; and Coke 113. 2 Fuel Oil (Pounds air per gallon): Commercial Standard No. 1, 102.6; No. 2, 1055; No. 5, 112; No. 6, 1143. 3. Gaseous Fuels (Cubic feet of air per cubic foot): Natural, 109; Mixed Natural and Manufactured, 89; Manufactured, 4.7, Propane, 235, Butane, 319. COMBUSTION EFFICIENCY FROM THE FLUE-GAS ANALYSIS Excess Air A commonly employed index of efficiency of combustion is the relation existing between the amount of air theoreti cally required for perfect combustion and the amount of air actually supplied. Since the difference between air supplied for combustion ,and theoretical air required is characterized as excess air, its percentage may be calculated by use of the following equation, ' Percent excess air Air supplied -- Theoretical air Theoretical air The amount of dry air supplied per pound of fuel burned may be obtained from. Equation 6 which has reasonable precision for most solid and liquid fuels. Values for CO*, CO and N, are percentages by volume from the flue-gas analysis, and C is the weight of carbon burned per pound of fuel, corrected for carbon in the ash. Pounds dry air supplied per pound of fuel 3.04N, XC (CO, + CO) (6) Because excess air calculations are almost invariably made from Orsat analysis results, and theoretical air requirements Table 8 . . Approximate Air Requirements for Theoretically Perfect Combustion of Fuels* type of Air Required for Perfect Confwdfos Approxfmate Lb per Lb Fuel Co Ft per Unit* Fuel % Exception* Solid Btu per lb Btu per lb X 0.00073 X 0.0097 liquid Btu per lb Btu per lb X 0.00071 X 0.0094 Gas Btu per lb Btu per cu ft X 0.00067 X 0.0089 3 3 5 Fuels contain ing more than 30% water Results low for gasoline and kerosine Gases of 300 Btu per cu ft or less * Value* in table taken from pace OT <* Oattsus Pud*. IMS, published by * Unit* for solid *od liquid fools in poonds, for c** in enfafe fast 480 CHAPTER 33 1959 Guide are not always known, another convenient method of ex pressing the relation of Equation 5 is as follows: Percent excess air 100(0, - CO/2) Nt X 0.264 - (0, - CO/2) (7) As measurement standards for gaseous fuels are almost universally expressed in cubic feet, Equation 8 may be em ployed for computing excess air on a percentage basis for gases." . (u - con P Percent excess air = ---- -----X 100 -- (8) where V *= ultimate carbon dioxide, percent of flue gases result ing from perfect combustion. ' COt carbon dioxide content of flue gases, percent. P " dry products from perfect combustion, cubic feet per . cubic foot of gas burned. A ** air theoretically required for complete combustion, cubic feet per cubic foot of gas burned. As the ratio of P/A is approximately 0.9 for most city gases, a value of 90 may be substituted for 100(P/A) in Equation 8 for rough calculation. Carbon-hydrogen ratios of different fuels vary consider ably, hence the maximum or ultimate CO, attainable fan varies. Where they, are unknown, theoretical maximum CO, values may be calculated from a flue-gas analysis by use of Equation 9. Maximum theoretical % COi _ % COt in flue gas sample X 100 ^ 100 (* same sampie\ \ 0.21 ; Approximate maximum CO, values for perfect combustion of several cbmmon types of fuel are shown in Table 9 to gether with values of CO, that will be attained with different Table 9 .... Approximate Maximum Theoretical CO* Values, and CO* Values for Various Fuels with Different Percentages of Excess Air Type of fuef Maxitevm forcenf CO, of Given Thoototicol or Ezcco Air Valve, Ultimate Portoaf CO, 20% 40% 40% Coke . Anthracite Bituminous Coal No. 1 and 2 Fuel Oil 21.0 20.2 18.2 15.0 17.5 16.8 15.1 12.3 15.0 14.4 12.9 10.5 13.0 12.6 11.3 9.1 No. 6 Fuel Oil Natural Gas C&rburetted Water Gas Coke Oven Gas 16.5 12.1 17.2 11.2 13.6 9.9 14.2 9.2 11.6 8.4 12.1 7.8 10.1 7.3 10.6 6.8 Mixed Gas (Natural and Car- 15.3 12.5 10.5 9.1 buretted Water Gas) Propane Gas (Commercial) Butane Gas (Commercial) 13.9 11.4 9.6 8.4 14.1 11.6 9.8 8.5 amounts of excess air. Desirable values to be attained in practice depend upon the fuel, the method of firing, and other considerations. In general, fuels burned in suspension, such as gas, oil, and pulverized coal, can be burned with a lower amount of excess air than fuels burned on grates. To produce heat efficiently by burning any common fuel, a number of basic requirements must be met: (1) adequate heat absorbing surface of proper shape and construction is necessary in the appliance, (2) heat transfer surfaces must be clean, (3) a minimum amount of excess air must be present, (4) air employed for combustion and combustible gases must be properly mured, and (5) flue-gas loses must be reduced to a safe minimum If insufficient heating surface is employed, or if heat trans fer surfaces are covered with soot, ash, or scale, flue losses will generally be excessive due to the large amount of sensible heat escaping to the chimney. Too much excess air dilutes flue gases excessively and increases sensible flue gas loss. On the other hand, a deficiency of excess air will in all prob ability cause incomplete combustion, and consequent escape of some unburned combustible gases from the appliance. Highest combustion efficiency is obtained when sufficient excess air is supplied and properly mixed with the com bustible gases. Even with appliances connected to an effec tive flue every reasonable precaution should be taken to in- ' sure as complete combustion as possible at all times. This is of vital importance in unvented equipment such as a gas space heater, for example. It is considered good practice to supply from 20 to 50 percent excess air, the exact amount depending on the kind of fuel burned and especially on the type of equipment in which it is utilized. Flue Gas Analysis . As radiation, convection, and conduction losses from com mon types of central heating appliances are largely em ployed in heating occupied spaces, flue-gas losses logically become the item of principal concern. Another reason for their importance is the fact that they are usually larger than all other heat losses combined. These important considera tions and others indicate not only the desirability but ab solute necessity of a reasonably accurate method for deter mining flue losses even if only approximate operating efficiencies are to be computed. Customary procedure in arriving at flue-gas losses is to make an analysis of a representative sample of flue gases and to measure their temperature. This information will enable the observer to compute the amount of flue gases produced, the. excess air, the actual quantity of air supplied for com bustion, and the flue losses. While the analysis of flue gases has been well described in several governmental and other scientific publications, the subject is of such importance that it warrants brief repetition here. Carbon dioxide and oxygen content are of principal interest in determining flue losses. Either or both of these values may be employed in such cal culations. While the former constituent is probably most commonly employed, special considerations may maVp the latter of greater interest. Fortunately, both can be deter mined readily by use of an Orsat gas analysis apparatus, a device of reasonably simple construction and design. .For field testing and burner adjustment, simple portable devices are available for determining carbon dioxide only. See Chap ter 44 for details regarding the operation of the Orsat ap paratus. The weight of dry flue gas per pound of fuel burned is Fuels arid Combustion widely used in combustion loss calculations. F^r^solid fuels this item may be determined by application of Equation 1- Pounds dry flue gas per pound fuel UCOt + 8Qt + UCO + Nt) " 3(CO, + CO) . c (1Q) Values for CO* 0,, CO, and N, are percentages by volume from the flue gas analysis, and C is the weight of carbon burned per pound of fuel, corrected for carbon in the ash. Total dry gas volumes of flue gases resulting from the combustion of one cubic foot of gaseous fuels for various percentages of CO, may be determined by application of Equation 11: Cubic feet dry flue gases per cubic foot fuel gas - Cubic feet COt produced per cubic foot of gss burned X 100 (11) Percent CO, by analysis After obtaining the quantity of flue gases from Equations 10 or 11, the excess air quantity may be determined by sub tracting the quantity of dry flue gases which would result from perfect combustion. Computations of flue losses are de scribed in the next section on Heat Balance. Application of the preceding equations and tables are il lustrated by Examples 1 and 2. Example 1: The analysis of the flue gases resulting from the burning of a natural gas is 109 percent CO,, 3.1 percent O,, and 869 percent N by volume. The analysis of the fuel is 90 percent CH*, 5 percent N,, and 5 percent C%H* by volume. Find U the maximum theoretical percent CO, and the percent excess air. Solution; From Equation 9: . (10.0X100) U 118% CO, 481 Water vapor, HiO (does not appear in Orsat analysis): (09 Cff)(2.0) ' = 18 (0.05 CtH,) (89/29) = 0.15 Total water vapor -- 195 cu ft Total volume of dry gas per cubic foot of gas: 8.69 + 032 + 100 = 10OI cu ft Total volume of wet gases per cubic foot of gas (neglecting water vapor in combustion air): 1001 + 195 = 1196 cu ft The cubic feet of dry flue gas per cubic foot of fuel gas may be computed from Equation 11 as follows: (1.00)000) 10.0 10.0 cu ft HEAT BALANCE The usual practice in analyzing the performance of heat ing appliances is to make an accounting, insofar as posable, of the disposition of all heat units available in the quantity of fuel burned. This accounting is called a heat balance. Various components of this balance are generally expressed in terms of Btu per pound of fuel burned, or as a percentage of its calorific value! Components of special interest are listed as items 1 to 7 inclusive. 1. Useful heat transferred to heating medium, usually com puted by determining the rate of flow of the heating fluid through the heating device, and the change in enthalpy of the fluid (heat added) between the inlet and outlet. 2. Heat loss in the dry chimney gases. hi -- WfC, (I,, -- t.) (12) 3. Heat loss in water vapor formed by the combustion of hydrogen. ft, = ~ (1089 ~ t. + 0.4550 (13) From Equation 8, Percent Excess Air (118 - 10.0) X 90 10 163 Example 2: For'the analyses in Example 1 find, per cubic foot of fuel gas, the cubic feet of diy air required for com bustion, the cubic feet of each-constituent in the flue gases, and tbe total volume of dry and wet flue gases. Solution: From Equation 3 (or Table 7) the volume of dry air required for combustion is: (983) (.CH*) ~f~ (16.68)(C,ff,) = 983 X 090 -I- 1688 X 095 = 9.41 cu ft/cu ft gas. From Table 7, the constituents per cubic foot of gas are: Nitrogen, V,: From methane = (09 CH*)(983 - 29) - 6.78 From ethane = (095 CVff)(1688 -- 38) -- 086 Nitrogen in fuel = 095 Nitrogen in excess air = 0.791 X 0.162 X 9.41 = 120 Total Nitrogen 889 cu ft Oxygen, O*: *. Oxygen in excess air = 0209 X 0.162 X 9.41 -- 032 cu ft Carbon dioxide, CO*: From methane -- (09CH*)(19) -- 090 - From ethane = (095C,H,)(49/29) = 0.10 Total Carbon Dioxide 190 cu ft 4. Heat loss in water vapor in tbe air supplied for com bustion. h, = 0.455 M w. - U) (14) 5. Heat loss from incomplete combustion. `*-10143C(cSTco) (15) 6. Heat loss from unburned carbon in the ash or refuse. h. - 14600" - Cj (W) 7. Radiation and all other unaccounted for losses. Radiation and convection losses from a heating appliance are not usually determined by direct measurement. For this reason they, together with any other losses not measured,, are determined by subtracting the total of items 1 to 6 from tbe heat of combustion of the fuel. If the heating appliance is located within the heated space, however, radiation mid convection losses may be considered as useful heat rather lost heat. They may, therefore, be omitted from calcula tions of heat losses, or added to item 1. If there is CO in the flue engpB, small amounts of unbumed hydrogen and hydrocarbons will probably also be present. The small losses 482 CHAPTER 33 1959 Guide due to inoomplete combustion of these letter gases would also be meluded in item 7. Symbols used in Equations 12 to 16 inclusive are: ht heat loss in the dry chimney gases, Btu per pound of fuel. A* * heat loss in water vapor from combustion of by- drogen, Btu per pound of fuel. ht -- heat loss in water vapor in combustion air, Btu per pound of fuel. h* =* heat loss from incomplete combustion of carbon, Btu per pound of fuel. ht * heat loss from unburned carbon in the ash, Btu per pound of fuel. "* weight of dry flue gas per pound of fuel (from Equation 10), pounds. Cp " mean specific heat of flue gases at constant pressure (fip ranges from 0.242 to 0.254 for flue tempera tures from 300 F to 1000 F),* Btu per pound. tt -- temperature of flue gases at exit of heating device, Fahrenheit. ' < -- temperature of combustion air, Fahrenheit. H* " percentage of hydrogen in fuel by weight from ulti mate analysis of fuel burned. 1091-8 --- enthalpy of saturated water vapor at a temperature of 70 F, Btu per pound. U -- humidity ratio of combustion air, pounds of water vapor per pound of dry air. w -- weight of combustion air per pound of fuel used, pounds, from Equations 2, 4, 5, 6, 7 and 8. CO, CO, " percentages of CO, CO, in flue gases by volume. C " weight of carbon burned per pound of fuel cor rected for carbon in ash, pounds. WCM - w.c. C 100IF . (17) Toble TO... . Averoge Rue Gos Dew Point for Various Fuels1 Tjp* of Fori Anthracite.. Semi-BitiiTnirmii<9 Coal Kittiminnua P-osl oa.................... ...................... Natural Gas............. Manufactured Gas Propane Gas (2500 Btu/cu ft)........... Butane Gas (3200 Btu/cu ft). . Butane-Air Gas Mixture (535 Rtn/on ft) Avorop* Dew Potaf Temper- afore, F 93 121 flue loss is indicated where the straight edge intersects the flue loss column. The operating efficiency of a gas appliance can then be computed with sufficient precision by application of Equation 18. Percent Combustion Efficiency = Gross Btu of fuel \ _ /total flue losses per\ kgas per cubic tool) \ cubic foot fuel gas / Gross Btu of fuel gas per cubic foot X 100 (18) where ' C9 " percentage of carbon in the fuel by weight from the ultimate analysis. Wm " weight of ash and refuse, pounds. Cm "= percent of combustible in ash by weight (combustible in ash is usually considered to be carbon). '; W weight of fuel used, pounds. Flue-gas losses for solid and liquid fuels, listed as items 2, 3 and 4 of the heat balance, may be determined with suffi,cient precision for most purposes from curves shown in Fig. 4,* if CO, content and temperature of flue gases are known. Values of the losses plotted for fuel oil were computed from the ultimate analysis of a typical fuel oil used in domestic burners, while those presented.for the several ranks of coal were computed from the typical ultimate analyses shown in Table 1. The curves for medium-volatile bituminous coal may be used for high-volatile bituminous coal with negligi ble error. Utilisation of gaseous fuels, for numerous reasons, is gen erally a more ample process than is the case with either solid or liquid fuels. Accordingly, the determination of a practical heat balance is also a more simple procedure in that items 5 and 6 do not generally apply to gas mstaH^rinno a. series of typical alignment charts has been combined in Fig. 5 for use in determining flue losses of items 2, 3 and 4 from common types of gas burning appliances. To determine flue loses place a straight edge extending from the corrected temperature reading to the percent CO, recorded. Percent A. outlet register for appliara room, laq in. tree Me* far 1000 Btu per hr sppliuM input betted abort relief opening of draft Reg*t- ter must not be hlocted by drape* or otter fanushings. 8. Both registers must either fsee --me large reotOated interior speee or ex tend to such epeee by mass of doete. Vertical distant C/L to C/L of reenters should be not lew JH ft. C- Suggest room aoce-- door be not leas than t ft high by a width to provide for installation or removal of appliance. At least 8 ft should be provided in (rout of appliance when eloaet door is open, or 18 in. rbrp door is closed. D- Combustion end ventilation air inlet register for appliance >< 1 aq in. freearea for each 1000 Btu per hr appliance input, located at orbelow ecsnbostion air inlet to appliance. Bcgbter must not be blocked by drmpm tx otter funxisb- E. Air circulated by appliance must be handled by duets whteh are --t~r to appliance earing and are entirely separate from ">*"? provided far supplying eambustioD end ventilation air. P. Spacing between draft hood end well et least 8 in. (unle-- approved fer doeer spacing). If flue products may be directed toward welt, U in. spacing recommended. O. No part of appliance casing doeer than B in. to well (unle-- approved for doeer spacing). H. Pineshould terminate above peak if roof and above werby wells to a--sre satisfactory flu* performance. * A value of 14600 applies in Mh pit leas; in formation of mrbon oompounds use 14068 Btu per lb. teat of Fig. 6 .... ({lustration Showing Air Openings Necessary" to Supply Air for Combustion When Appliance is Installed in Confined Space Fuels arid Combustion 483 M w3 S,, 5 a. 3aa. 9 P3 fi a o 6 3a. jafjs g '"U 5 g& 33 i3o> *o m a g S o *" e* Table 11____ Permanent Openings for Air Supply to Spaces Containing Fuel-Burning Equipment Furi-Sorafeg fqvqwpecf Equipment in a large enclosure hav ing adequate air infiltration Equipment in a large enclosure hav ing unusually tight construction Free Atm of Ventilating Opening* Air Inlet Air Outlet None required None required Total frfee area communicating with outdoor air not leas than ) sq in. per (1000 Btu) (hr) furnace input Total free area communicating with outdoor air not less than ^ sq in. per (1000 Btu) (hr) furnace input Equipment in a small enclosure in a building having adequate air in filtration Opening in party wall or door, (above draft hood) with free area of not less f^*n 1 sq in. per (1000 Btu) (hr) furnace input Opening in a party wall or door, (below combustion air inlet to appliance) with free area of not less than 1 sq in. per (1000 Btu) (hr) furnace input Equipment in a small enclosure in a building of unusually tight con struction Equipment in an enclosure having adequate air infiltration Grilled opening connecting directly with outdoors, through duct if nec essary; free area not less than H sq in. per (1000 Btu) (hr) furnace in put Total free area equivalent to not less than the combined area of the flue outlets of all fuel-burning equip ment in the space . Grilled opening connecting directly with outdoor air, through duct if necessary. Area and location same as above- . None required Equipment in an enclosure having unusually tight construction Total free area equivalent to not less than twice the combined area of the flue outlets, of all fuel-burning equipment in the space None required Reference to Table 9 will show that ultimate CO, percent age values of fuel gases vary. While personal errors involved in CO,, temperature, and chart determinations, would doubtless more than offset any inaccuracies due to universal use of the alignment charts shown, precise laboratory work may require a more exact method. For more complete in formation the reader is referred to combustion, 3rd Edition, and Gaseous Fuels, (published by American Gas Associa tion) .nd particularly to tables covering various.properties of different commercial gases included in these publications. CONDENSATION AND CORROSION Sulfur dioxide or sulfur trioxide, formed by the combus tion of sulfur in fuels, are the principal corroding substances in flue gases. They become active whenever sufficient mois ture is present for the formation of sulfurous or sulfuric acid,* and they lower the dew points of flue gases appreci ably. Therefore, unless heating equipment is designed for operation at flue-gas temperatures below the dew point, winch is seldom the case, it is always advisable to maintain temperatures above this value in all parts of the appliance. Excessive spot temperatures in the combustion chamber or elsewhere, on the other hand, are also destructive in that they may result in rapid oxidation of ordinary heating surfaces. American Standard Requirements for gas furnaces, floor furnaces, and recessed heaters, for example, specify that minimum spot heating surface temperatures during normal operation must neither fall below 178 F (50 F above aver age dew point) nor exceed 830 F to 1230 F on any portion of the heating surface, depending on the type and thickness of the metal. In any event it is usually desirable to maintain flue-gas temperatures within the limits indicated not only throughout the appliance, but in its connecting vent, flue, or chimney as well. Otherwise, excessive condensation and corrosion problems, with resultant customer dissatisfaction, will in all probability be the result. Average dew-point temperatures of flue resulting from the combustion of various fuels, when burned with the amount of excess air normally supplied to insure complete combustion, are shown in Table 10- SOOT The deposit of soot on the flue surfaces of a boiler or heater acts as an insulating layer over the surface, and reduces the heat transmission to the water or air. The Bureau of Mines Report of Investigations No. 3272" shows that the loss of seasonal efficiency is not so great as has been believed, and usually is not over 6 percent because the greater part of the beat is transmitted through the com bustion chamber surfaces. The Bureau of Standards Report BMS 54" points out that, although the decrease in efficiency of an oil fired boiler, due to soot deposits, is relatively small, the attendant increase in stack temperature may be considerable. . The soot accumulation clogs the flues, reduces the draft, and may prevent proper combustion. Soot can probably be most effectively removed by a jet of compressed air, by nip>na of a brush, or a vacuum cleaner. However, it has been found that copper chloride, lead chloride, tin chloride, f.in< chloride, common salt and some other salts are par tially effective in removing soot from furnaces and boilers when properly used." A discussion of instruments and methods of evaluating smoke will be found in Chapter 44. AIR SUPPLY TO FUEL-BURNING EQUIPMENT All rooms or spaces containing boilers, furnaces, water heaters, or any other fuel-burning equipment must be provided with a constant supply of combustion air at adequate static pressure -to insure proper combustion in the fuel burners. Additional air is required to replace air entering chimneys through draft hoods and' barometric draft dampers, and also, to provide ventilation in closely confined boiler and furnace rooms. Experience has shown that the ventilating air openings 484 CHAPTER 33 1959 Guide required in heater rooms depend not only on the size of the heating plant but also on the type of fuel being burned, the relative size of the equipment room, the tightness of building construction, and the operation of exhaust fans or other devices which affect the static pressure in a building. Because of the number of variables involved in establish ing air requirements, and the variations in building con struction and arrangement, there is no universally accepted rule for providing ventilating openings. However, the im portance of providing proper ventilation should not be underestimated, and a failure to do so may result in erratic or even dangerous operating conditions for equipment. Rules for providing air supply openings are found in technical standards,** " in state and municipal building codes and in service and installation bulletins published by various manufacturers of fuel-burning appliances. Table 11 is a compilation of reasonably consistent data taken from a number of these sources, and should be used only as an aid to independent judgment for any particular installation. Ventilating air requirements are particularly critical for . residential type appliances in closely confined rooms. Fig. ' 6 illustrates minimum requirements for this type of in stallation. * P. Nicholls and C. W. Staples: Removal of Soot from Furnaces and Flues by the Use of Solis and Compounds, (U. S. Bureau of Mines Bulletin No. 360). ' **American Standard for Installation of Gas Piping and Gas Appliances cn BtriUHngs (American Gas Association, 1954, ASA Z 2130). " NBPU Standard for the Installation of Oil Burning Equipments (National Board of Fire Underwriters, NBPu Pamphlet No. 31). BJptlOGRAPHY Hashun and Russell: Fuels and Their Combustion (Mc Graw-Hill Book Co., New York, 1926). A. D. Pratt: Principles of Combustion in the Steam Boiler Furnace (Babcock and Wilcox Co.). B. J. Rose and F. P. Lasseter: Smoke-producing tendencies in coals of various ranks (ASHVE Transactions, Vol. 45, 1939, p. 329). C. A. Barnes: Fundamentals of Combustion m Small Stokers (Bituminous Coal Research, Inc. Technical Report No. IV). A. P. Kratz, J. R. Fellows, and J. C. Miles: Hand-firing of Bituminous Coal m the Home (Illinois Engineering Ex periment Station Circular No. 46). G. H. Cady: Classification and Selection of Illinois Coals (Illinois State Geological Survey Bulletin No. 62). - REFERENCES 1 Five Hundred Testa of Various Coals in Househeating 'Boilers (U. S- Bureau of Mines Bulletin No. 276). 'A. P. Krata, $. Eonzo, and D. W. Thompson: Combustion Efficiencies as Related to Performance of Domestic Heating Plants (University of Illinois, Engineering Experiment Station Circular No. 44). *Quatitv of Anthracite as Prepared at Breakers ((/. S. Bureau of Mines Repent of Investigation, 1936 R, I. 3283). ` Hand Firing Soft Coal Under Power Plant Boilers (U. S. Bureau of Mines Technical Paper No. 80). . 1ASTM Test Dwqmotwm D287-39. *A8TM Test Designation D611-43T. ' W. A. Sullivan sad E. B. Glendenning: Tomorrow's fuel oil (Fueloil and Oil Heat, Vol. 4, May 1945, p. 36). * The correlation of cetane number with other physical properties at diesel fuels (Journal of the Institute of Petroleum, VoL 30, 1944, p. 193). * R. M. Watson, E. F. Nelson, and G. B. Murphy. Char acterisation of petroleum fractions (Industrial and Engineer ing Chemistry, Vol. 27, December 1935, p. 1464). " J. C. Reid and A. B. Hersberger: Burning index for distillates (Fueloil and Oil Heat, Vol. 5, January 1947, p. 90). US. P. Cauley and E. B. Delgass: Carbon hydrogen ratio of catalytically cracked distillate fuel oils (Oil and Gas ` Journal, Vol. 45, July 27, 1946, p. 166). ; UD. W. Locklin and G. V. Parmalee: Rating of fuel oils by a test unit (ASHVE Transactions, Vol. 57, 1951, p. 139). "Gaseous Fuels (American Gas Association, 1948, p. 32). - " V. J. Altieri: Go* Analysis and Testing of Gaseous Materi als (American Gas Association, 1945, 1st ed.). "Tentative Methods of Test far Specific Gravity of Gaseous' Fuels (American Society for Testing Materials, ASTM Designation: 1070-49). ' "Standard Method of Test for Calorific Value of Gaseous Fuels by the Water-flow Calorimeter (American Society for Testing Materials, ASTM Designation: 900-48). - "Domestic Gas Range Research (American Gas Associa tion Laboratories Bulletin 7, p. 64). **W. R. Morgan: Condensation of Moisture in Ftaes (University of Illinois, Engineering Experiment Station Cir cular No. 22). Bftwntaous Coal Research, hej J. M. Pilcher and R. A. Sherman: The Treatment of Coal wVIit)h. Oil and Other Petroleum Products (Technical Report R. A. Sherman and G. W. Land: Dustless Treatment of Coals with Materials Other Than Oil (Information Bulletin No. 4). Questions and Answers on the Use of Fuel Oil for Dustless Treatment (Information Bulletin No. 6). R. B. Bngdahl: Application of Overfire Air Jets (Technical Report VII). Bureau of Mines Publications! Henry Kreisinger and F. K. Ovite: Sampling and Analysing Flue Gases (Bulletin No. 97). P. Nicholls and B. A. Landry: Coke as a Domestic Heating Fuel (Report of Investigations, R. I. 2980). John Blizard, James Neil, and F. C. Houghten: Value of Coke, Anthracite, and Bituminous Coal for Generating Steam in a Low-pressure Cast-iron Boiler (Technical Paper No. 303). P. Nicholls: Effect of Preheat, and Distribution of Ash in Fuel Beds (Bulletin 378). . J. F. Barkley: Handbook, Questions and Answers for the Home Fireman (Revised). Anthracite tndtntries Laboralorie* Publications: ' Comparison of Sizes, Egg, Stove and Chestnut Anthracite (Report 2015). Domestic Survey (Report 2018). Utilization of Anthracite for Domestic Heating (Report 2062). The Crater Method of Firing (Report 2204). Anthracite Industries Manual (Report 2403). OQ and Gas Publication* ` J. A. Moyer: Oil Fuels and Burners (McGraw-Hill Book Co., New York, 1937). Combustion ("Industrial Gas Series,'' American Gas As- sodation). Comfort Heating (American Gas Aaociatiou). Gaseous Fuels (American Gaa Association, 1954). F. H. Faust and G. T. Kaufman*. Handbook of Oil Burning (Oil-Heat Institute of America, 1951). . ".Effect of Soot on Heat Transmission m Boilers (V. S. Bureau of Mines Report of Investigation No. 3272). * Effect of Soot on the Rating of an Oil-fired Heating Boiler (National Bureau of Standards Report BMS 54). E. R. Weaver*. Formulas and graphs for representing the interchangeability of fuel gases (National Bureau of Standards Journal of Research, 1951, Research Paper R. P. 2193). * Lewis and von Elbe: Combustion Flames and Explosions of Gases (Acsdemie Press, New York, 1951). CHAPTER 34 AUTOMATIC FUEL-BURNING EQUIPMENT Classification of Stokers, Combustion Process and Adjustments, Furnace Design, Rating; Classification of Oil Burners, Combustion Process, Combustion Chamber Design; Commercial and Industrial Oil Burners, Types of Burners; ' Storing and Handling Heavy Fuel Oil; Oil Storage Tanks and Piping; Classification of Gas-Fired Heating Equipment, Combustion Process, Ratings; Sizing of Gas Piping, Commercial and-Industrial Gas Equipment; Fuel-Burning Rates; Controls for Automatic Equipment AUTOMATIC mechanical equipment for the combustion X\. of solid, liquid, and gaseous fuels is considered in this chapter. The type of fuel to be burned affects the design of the heat exchanger (furnace, boiler, etc.); therefore, one should refer to Chapter 35, Heating Boilers, Furnaces, Space Heaters when considering fuels and fuel-burning equipment. Some heat exchangers are designed specifically for one type of fuel. As a result, maximum efficiency and best perform ance require the simultaneous consideration of fuel and fuel burning equipment during the initial stages of equipment selection. MECHANICAL STOKERS A mechanical stoker is a device that feeds a solid fuel into a combustion chamber, provides a supply of air Tor burning the fuel under automatic control and, in some cases, incor porates a means of removing the ash and refuse of combus tion automatically. Coal can be burned more efficiently by a mechanical stoker than by hand firing because the stoker provides a uniform rate' of fuel feed, better distribution in the fuel bed; and positive control of tie air supplied for com bustion. In many cities, measures for control of excess smoke re quire installation of stokers even in residences, unless fuel used contains less volatile matter than bituminous coal. Classification of Stokers According to Capacity Stokers may be classified roughly according to their coal burning capacities, as follows: Class 1 Class 2 Class 3 Class 4 10 to 100 lb per hr 100 to 300 lb per hr 300 to 1200 lb per hr over 1200 lb per hr Class 1 Stokers .. - These stokers are used primarily for home heating and are designed for quiet, automatic operation. Simple, trouble-free construction and attractive appearance are desirable churnc- teristics of these small units. A common stoker in this class (Fig. 1) consists essentially of a coal hopper, a screw for conveying the coal from the hopper Co the retort, a fan that supplies the air for com- bustion, a transmission for driving .the coal feed worm, and an electric motor for supplying power for coal feed and air supply. . Air for combustion is admitted to the fuel through tuyeres at the top of the retort which may- be either round or rec tangular. Stokers in this class are made for burning anthra cite, bituminous, semi-bituminous, and lignite coals, and coke. The U. S. Department of Commerce has issued com mercial standards for household anthracite stokers.1 Units are available in either the hopper type, as shown in Fig. 1, or in the bin-feed type as shown in Fig. 2. Some stokers, particularly those designed for use with anthracite, automatically remove ash from the ashpit and deposit it in an ash receptacle. Most of the bituminous models, however, require hand removal of the'ash from the fuel bed after it is fused into a clinker. Stokers in this class feed coal to the furnace intermittently in accordance with temperature or pressure demands. A special control is used to insure sufficient stoker operation to maintain a fire during periods when no heat is required. Gass 2 Stokers Stokers of this class are usually of the underfeed motor- driven screw type, Fig. 3, and are used extensively for beat ing apartments, schools, hotels, and industrial plants. They are also built in plunger-feed type, Fig. 4, with electric motor or steam or hydraulic cylinder coal feed drive. The tuyeres and retort design vary according to the fuel and load condi tions. They are available for burning all types of anthracite, bituminous and lignite coals. - Stationary type grates or dead plates surround the retort of bituminous models to collect the ash and clinkers which are removed periodically by band. Anthracite stokers in this class may be equipped with moving grates that discharge the ash into a pit, below the grates, having capacity for several weeks of ash accumulation. . Gass 3 and 4 Stokers These stokers are: underfeed side cleaning, underfeed rear cleaning, overfeed fiat grate, or overfeed inclined grate type. Underfeed side cleaning stokers are made in sizes up to about 500 boiler horsepower (or approximately 17 million Btuh). They are not so varied in design as those in the smaller classes, although the principle of operation is simi lar. A stoker of this type is illustrated in Fig. 4. The rear cleaning underfeed stoker is usually of the mul- ' . Fig. 1.... Underfeed Stoker, Hopper Type, Class 1 485 ' ' x' 486 CHAPTER 34 1959 tipis retort design. It is used in some of the largest indus trial plants and central power stations. Zoned sir control has been applied to these stokers, both longitudinally and trans versely of the grate surface. The overfeed fiat grate stoker is represented, by the vari ous chain- or traveling-grate stokers. Another distinct type of overfeed fiat-grate stoker is the spreader type in which coal is distributed either by rotating paddles (Fig. 5) or by air over the entire grate surface (Fig. 6). Thu type of stoker is adapted to a wide range of fuels and has a wide application on TMll sized fuels, and on fuels such as lignites, high-ash coals, and coke breeze. The overfeed inclined-grate stoker operates on the same general combustion principle as the fiat-grate stoker, the' Fig. 3------ Underfeed Screw Stoker, Hopper Type, Gass 2 or 3 pud" difference being that rocking grates, set on an incline, are provided in the former to advance the fuel during com bustion. ' Combustion Process . while finally the ash is disposed of at the sides. This type of stoker is suitable for all bituminous coals, while in the smaller sizes it is suitable for small sizes of anthracite. In this type of stoker the fuel is delivered to a retort beneath the fire and is raised into the fire. During this process the vola In anthracite stokers of the Class 1 underfeed type, burn tile gases are released, are mixed with air, and pass through ing takes place entirely within the stoker retort. The refuse the fire where they are burned. The ash may-be continuously of combustion spills over the edge of the retort into an ash or periodically discharged at the sides. pit or receptacle from which it may be removed either The underfeed rear-cleaning stoker accomplishes combus manually or automatically. Anthracite for stoker firing is tion in much the same manner as the tide-cleaning type, but usually pea, buckwheat, rice, or barley size (see Chapter 33 for a description of size). consists of several retorts placed tide by tide and filling up the furnace width, while the ash disposal is at the rear. In Because the majority of the small bituminous coal stokers principle, its operation is the same as the tide-cleaning operate on the underfeed principle, a general description of underfeed type. theii operation is given. When the coal is ted into the retort, Overfeed flat-grate stokers receive fuel at the front of the it moves upward toward the zone of combustion and is grate in a layer of uniform thicknes and move it horizon heated by conduction and radiation from the burning fuel tally to the rear of the furnace. Air is supplied under the in the combustion zone. As the temperature of the coal rises, moving grate to carry on combustion at a sufficient rate to it gives off moisture and occluded gases, which are largely complete the burning of the coal near the rear of the furnace. noncombustibles. When the temperature increases to around The ash is carried over the back end of the stoker into an 700 or 800 F the coal particles become plastic, the degree of plasticity varying with the type of coal. ashpit beneath. This type of stoker is suitable for small sizes of anthracite or coke breeze, and also for bituminous A rapid evolution of the combustible volatile matter oc coals, the characteristics of winch make it desirable to burn curs during and directly after the plastic stage. The distil the fuel without disturbing it. This type of stoker requires lation of volatile matter continues above the plastic zone an arch over the front of the fuel bed to maintain ignition where the coal is coked. The strength and porosity of the of the incoming fuel, and frequently a rear combustion arch. coke formed will vary according to the size and character Overfeed inclined-grate stokers are provided with rocking istics of the coal. While some of the ash fuses into particles grates and ash plates on which ash is accumulated and on the surface of the coke as it is released, most of ifremains dumped periodically. This type of stoker is suitable for all on the hearth or grates and, as this ash layer becomes thicker types of coking fuels, but preferably for those of low volatile with time, that portion exposed to the higher temperatures content. Its grate action keeps the fuel bed broken up, surrounding the retort fuses into a clinker. The temperature t thereby aUtcwing iree passage o! air. Because of its agitating in the fuel bed, the chemical composition, and homogeneity effect on the fuel, it is not desirable for badly clinkering of the ash, and the time of heating govern the degree of fusion. . coals. It usually should be provided with a front arch to ig nite the volatile gases. . Most bituminous coal stokers of Classes 1, 2, and 3 require nM*nu*l removal of the ash in clinker form. Combustion Adjustments In the underfeed side-cleaning stokers the fuel is intro duced at the front of the furnace to one or more retorts, and is advanced away from the retort as combustion progresses, The coal feeding rate and air supply to the stoker should be regulated so as to maintain a balance between the load Fig. 2-------Underfeed Stoker, Bin Feed Type, Class l fig. 4 .... Underfeed Side Cleaning Stoker . Automatic Fuel Burning Equipment 487 For burning rates from 100 to 1200 lb coal per hour . H - 0.03 B + 24 (2) demand and the heat liberated by the fuel. Under such con ditions, no manual attention to the fuel bed should be re quired, other than the removal of clinker in stokers which operate on this principle of ash removal. As in all combustion processes, the maintenance of the correct proportions of air and fuel is essential. It is desirable to supply the minimum amount of air required to properly bum the fuel at the rate of feed. ' While there may be only slight variations in the rate at which the coal is being fed, due to variations in the size or density of the coal, there may be wide variations in the rate of air flow as the result of changes in fuel-bed resistance. These changes in resistance may be caused by changes in the porosity of the fuel bed due to variations in size or friability of the coal, ash and clinker accumulation, and variations in depth of the fuel bed. Because of this variable fuel bed re sistance, many bituminous stokers, even in the smaller do mestic sizes, incorporate air controls which automatically compensate for these changes in resistance and maintain a constant air-to-fuel ratio. The efficiency of combustion may be determined by analyzing the flue gases,, as explained in Chapters 33 and 44. _... It is desirable on most stoker installations to provide auto matic draft regulation in order to reduce"air infiltration and provide better control during the banking, or off, periods of the stoker. It is imperative that adequate combustion air be supplied and, therefore, it is usually necessary to provide a direct outdoor opening for this purpose. (See Chapter 33.) Combustion Chamber Design The Stoker Manufacturers''Association has published standard recommendations on setting heights for 'stokers having capacities up to 1200 lb of coal per hour * The empirical formulas for ..determining these setting heights are: . For burning rates up to 1001b coal per hour H * 0.1125 B + 15.75 (1) where ti = minimum setting height, inches, measured from dead plates to crown sheet for steel boilers. For cast-iron boilers height may be % H. B -- burning rate coal per hour, pounds. Standards for minimum firebox dimensions and base heights have been formulated by the Stoker Manufacturers Association as shown in Fig. 7.* In considering these recommendations, it should be under stood that they show the average recommended minimum. There are many factors affecting the proper application of stokers to various types of boilers and furnaces, and, in cer tain instances, setting height or firebox dimensions shown in the standards may be modified without impairing perform ance. Such modification will depend upon the experience of the installer or designer with a particular stoker, the type of fuel used, and the construction of the boiler or furnace. Installation of stokers (particularly Smaller sizes) on the side of the boiler or furnace may facilitate clinker removal. Rating and Sizing Stokers The Stoker Manufacturers Association*1 * has suggested a method for rating solid fuel stokers as follows: _____ Load (Btu per hour)__________ Stoker burning rate Heating value of coal (Btu perpound) * required (pounds of X overall efficiency of stoker eo^ Per hour) and boiler or furnace In determining the total load placed on a stoker-fired boiler by a steam or hot water heating system, a piping and pickup factor of 1.33 is commonly used in ging the stoker, but this factor should be increased at times due to unusual conditions. . Controls The control of coal-fired equipment is diangaerf in the section Controls for Automatic Fuel-Burning Equipment. DOMESTIC OIL BURNERS An oil burner is a mechanical device for the oxidation of hydrocarbon liquids (fuel oil) and air under controlled con- totaa w01 permit tttislftetary perfenouxs bat theae dimmirinna tn preferred Fig. 6____ Overfeed Spreader Stoker (Pneumatic Type) Fig. 7 .... Suggested Minimum firebox Dimensions and Base Heights* 488 CHAPTER 34 1959 Fig. 8 .... High-Pressure Atomizing Oil Burner conditions. Two methods, atomization and vaporization, are employed for the preparation of the fuel oil for the com bustion process. Air for combustion is supplied by a blower or by draft produced by the chimney. Ignition is accom plished by an electric spark, electric resistance wire, gas pilot flame, or oil pilot flame. Burners of different types operate with luminous or non-luminous flame. Operation may be in termittent or continuous with high-low flame. ' Oil burners must be used with a sealed heat exchanger (warm air furnaces, boilers, water heaters, space beaters, . etc.), and must have a proper venting system. While most oil burners operate from automatic tempera ture-sensing controls, some of the ampler types are operated manually. - Gassffication of Burners - Domestic oil burners may be classified by type of design or operation into the following groups: pressure-atomizing or gun, rotary, and vaporizing or pot. These are further clas sified as mechanical draft, and natural draft. Pressure Atomizing (Gun-Type) Burner Gun-type burners are usually designed to burn No. 1 or 2 grade fuel oil. They may be divided into two classes: highpressure and low-pressure atomization. The high-pressure atomizing type, illustrated in Fig. 8, is characterized by an air tube, usually horizontal, with oil sup ply pipe centrally located in the tube and arranged so that a Fig. 9 .. Wall Flame Vertical Rotary Burner spray of atomized oil is introduced at about ICO psi, and mixed in the combustion chamber with the air stream emerg ing from the air tube. The oil rate can be changed by replacing the nozzle with one of different rating. Oil nozzles are precision devices for metering the oil and discharging the oU in a fine spray or mist. Small oil-rate changes can be made by adjustment of pump pressure. Good atomization is affected at pressures between 75 and 140 psig. Since the objective is to mix in timately the oil spray particles and air, a variety of baffles or mixing, devices are employed in the air tube. The air velocity and direction is important in this mixing. The oil pump can perform both as a suction pump (oil tank below burner), and a pressure pump for atomization. A blower is used to supply the air for combustion. A damper or other adjustable means at the burner and a draft regulator maintain a proper air supply. Ignition is estab lished by a high-voltage electric spark that may be operative continuously while the burner is running, or just at the be ginning of the running period. The burner operates on the intermittent on-off principle, and with a luminous flame. The combustion process is completed in a chamber con structed of refractory material, or stainless steel, this being a part of the installation. ' The low-pressure atomizing burner differs from the high- pressure type mainly by having means for supplying a mix ture of oil and primary air to the burner nozzle. The air pressure before mixing and the pressure of the oil-air mix ture at the nozzle vary with different makes of burners, but are in a low range of 1 to 15 psig for the air and 2 to 7 psig for the mixture, respectively. The various parts of the burner, except for oil and air mixing parts, are the same as shown in Fig. 8. < Rotary Burner 'Most of the smaller rotary burners are of the vertical wall flame type (Fig. 9), and are used with No. 1 or 2 grade fuel oil. Oil is conveyed by gravity to the burner and is cen- trifugaiiy thrown and mixed with air to a periphery ring of stainless steel or refractory material.-A refractory hearth is used to prevent excessive heat loss below the burner and to prevent air leakage. Oil rate and air quantity can be ad justed to suit requirements. . The vertical rotary burners are further characterized by their installation within the ashpit of the boiler or furnace. - Various types of ignition are utilized, gas and electric, either Automatic Fuel Burning Equipment 489 spark or hot wire. The air for combustion is supplied par tially by natural draft, and partially by fan effect of the central spinner element. .. Vaporizing Burner In the vaporizing burner, fuel oil is ignited (manually or electrically) and vaporized in a vessel or pot which is open at the top. Heat for vaporization is supplied by the combus tion process. Openings in the ride walls of the burner admit primary air which forms a rich mixture of air and oil vapors in the burner. Adjacent to the outlet opening, sufficient ad ditional or secondary air is admitted to complete combustion. The openings for admitting air are arranged to obtain grad ual and intimate mixing of air and oil vapor for combustion. Fuel is fed by gravity from a constant level control valve, and the flow is either on (at rated capacity) or off (at pilot flow), according to the demand of the thermostat. However, the high fire can be reduced and the pilot fire can be in creased to give almost any desired control characteristic within the range of the burner. The majority of vaporizing Bg. 11 .... Vaporizing Gravity Pot-Type Burner . burners are manufactured in sizes up to one gallon per hour input. Most vaporizing burners are limited to use with No. I fuel oil having a maximum end point of 625 F and a mini mum API gravity of 35 deg. A barometric draft regulator is required to maintain the recommended draft. A draft of not more than 0.06 in. of water column is recommended for most natural draft burners. When burners are equipped with mechanical forced draft, a slightly lower chimney draft can be used. A burner of this type is illustrated in Fig. 10. A gravity type is shown in Fig. 11. . Oil-Fired Boiler and Furnace Units A number of types of specially designed oil-fired boilerburner and furnace-burner units are available. Various lo cations of burners will be noted in such units; some having the combustion chamber and burner at the top, some at the bottom, and some at the center of the appliance. Typical combination units are shown in. Figs. 12 and 13. The co ordinated design of boiler (or furnace) and burner elements insures the optimum in operating characteristics, and the maintenance of balanced performance. Hus type of equip ment usually has more heating surface, and better flue pro portions and gas travel than conventional boilers or furnaces. Some of the better conversion installations, however, may equal the unit type in performance. Operating Requirements for Oil Burners The U. S. Department of Commerce, in conjunction with the oil burner and heating appliance industries, has estab lished commercial standards for conversion burners and burner-appliance units which cover installation, construction and performance tests.* Combustion Process Efficient combustion must produce a clean flame and use a relatively small excess of air, ie., between 25 and 50 percent. This can be done only by vaporizing the oil quickly and completely, and mixing it vigorously with air in a combus tion chamber hot enough to support the combustion. A vaporizing burner prepares the oil for combustion by trans forming the liquid fuel to the gaseous state by the appli cation of heat. ' - In an atomizing burner, the oil is mechanically separated into very fine particles so that the surface exposure of the liquid to the radiant heat of the combustion chamber is vastly increased and vaporization thereby promoted. The result is the ability to burn more and heavier oil within a given combustion space. Because the air enters the combus tion chamber with the liquid fuel particles, mixing, vaporiza tion, and burning occur all at once in the same space. This produces a luminous flame. A deficient amount of air is in dicated by a dull red or dark orange flame with smoky tips. An excessive supply of air may produce a brilliant white flame or a short ragged flame with incandescent sparks flashing through the combustion space. While extreme cases may be detected, it is not posable to distinguish, by eye, the effect of the finer adjustment which competent installation requires. 490 CHAPTER 34 1959 Combustion Adjustments The present-day oil burner with mechanical oil and air supply, properly installed and equipped with an automatic draft regulator, is capable of maintaining efficient combus tion foT a considerable period following the initial adjust ments of oil and air. Eventually, certain changes will occur, and may be such that the amount of excess air will de crease below allowable limits. A decrease in air supply while the oil delivery remains constant, or an increase in oil delivery while the air supply remains constant, will make the mixture of oil and air too rich for clean combus tion. The more efficient the adjustment, the more critical it will be. Hie oil and air supply rates must remain constant. The following factors may influence the oil delivery rate: (1) changes in oil viscosity due to temperature change or variations in grade of oil delivered; (2) erosion of atomising nozzle; (3) fluctuations in bypass relief pressures; and (4) possible variations in methods of atomization. Any change due to partial stoppage of oil delivery will increase the pro portion of excess air. This will result in less heat, reduced economy, and possibly a complete interruption of service. The following factors may influence the air supply: (1) changes in combustion draft due to a' variety of causes (i.e., changes in chimney draft because of weather changes, sea sonal changes, back drafts, failure or inadequacy of auto matic draft regulator, use of chimney for other purposes, posable stoppage of the chimney, and changes in draft re sistance of boiler due to partial stoppage of the flues); and (2) changes in air inlet adjustments at the fan. There should be no air leakage into the boiler or furnace setting. The overfire draft should be reduced as low as is consistent with the proper disposal of the products of com bustion. When using mechanical draft burners with average conditions, the combustion chamber draft should not be allowed to exceed 0.02-0.05 in. water. An automatic draft, regulator is necessary in order to maintain constant draft conditions which, in turn, improve efficiency of operation. The draft regulator should be adjusted in accordance with the manufacturer's instructions. . - Even though a fan is generally used to supply the air for combustion, in most oil burners, the importance of a proper chimney should not be overlooked. The chimney should have sufficient height and size to insure a uniform draft within the limits given, if maximum efficiency throughout the heat ing season is to be maintained. Measurement of the Efficiency of Combustion Since efficient combustion is based upon a clean flame and definite proportions of oil and air employed, it is pos sible to determine the results by analyzing the combustion gases. It is customary to analyze only for carbon dioxide (CO,) and to obtain the temperature of the stack gas. A showing of 10 to 12 percent indicates the best adjustment, if the flame is clean. Most of the good installations operate with 8 to 10 percent CO,. Taking into account the potential hazard of. low excess air (high CO,), a setting to give 10 percent OO, constitutes a reasonable standard for most oil burners. Commercial Standard CS-75 requires that oil burners labeled as complying with the standard shall ob tain smoke-free combustion at 10 percent CO,. In all cases smokeless combustion is a requirement for oil burners. Combustion Chamber Design With burners requiring a refractory combustion chamber, the size and shape should be in accordance with the manu facturer's instructions. It is important that the chamber be as nearly airtight as is possible, except when the particular burner requires a secondary supply of air for combustion. The atomizing burner is dependent upon the surrounding heated combustion chamber surfaces to vaporize the oil and support combustion. Unsatisfactory combustion may be due to inadequate atomization and mixing. A combustion cham ber can only compensate for these things to a limited extent. If liquid fuel continually reaches some part of the fire brick surface, a carbon deposit will result. The combustion chamber should enclose a space having a shape similar to the flame, but large enough to avoid flame contact. The nearest approach in practice is to have the bottom of the combustion chamber flat, but far rimigh below the nozzle to avoid flame contact, the sides tapering from the air tube at the same angla as the nozzle spray, and the back wall rounded. A plan view of the combustion chamber resembles in shape the outline of the flame. This insures quick vapori zation, rapid combustion and better mixing by eliminating dead spaces in the combustion chamber. An overhanging arch at the back of the fire pot is sometimes used to increase the flame travel and give more time for mixing and burning, and sometimes to prevent the gases from going too directly into the boiler flues. When good atomization and vigorous mixing are achieved by the burner, combustion chamber de sign becomes a less critical matter. Where secondary air is used, combustion chamber design is quite important. When installing some of the vertical rotary burners, the manufac turer's instructions must be followed carefully when install ing the hearth upon which successful performance de pends in this type of burner. Boiler Settings Since the volume of space available for combustion is a determining factor in oil consumption, it is general practice to remove grates and extend the combustion chamber down ward to include or even exceed the ashpit volume; in new installations the boiler may be raised to make added volume available. Approximately 1 cu ft of combustion volume should be provided for every developed boiler horsepower, and in this volume from 1.5 to 2.5 lb of oil per hour can property be burned. This corresponds to an average libera tion of about 38,000 Btuh per cu ft. At times much higher fuel rates may be satisfactory. For best .results, care should be taken to keep the gas velocity below 40 fps. Where checkerwork of brick is used to provide secondary air, good practice calls for about 1 sq in. of opening for each pound of oil fired per hour. Such checkerwork is best adapted to fiat flames, or to conical Bumw that nan be spread over the floor of the combustion chamber. The proper bricking of a large or even medium sized boiler for oil firing is impor tant, and frequently it is advisable to consult an authority on this subject. It is essential in combustion chamber design to prevent flama impingement upon either metallic or fire brick surfaces. Manufacturers of oil burners usually have available detailed plans for adapting their burners to var ious types of boilers, and such information should be uti lized. Controls The control of oil-fired equipment is discussed in the sec tion Controls for Automatic Fuel-Burning Equipment. COMMERCIAL AND INDUSTRIAL OIL BURNERS Oil-burning equipment for commercial and industrial ap plications is usually designed for bunting the lower cost Automatic Fuel Burning Equipment . . 491 heavy fuel oils such as U. S. Commercial Standard Grades Nos. 4, 5, and 6. The viscosity of these oils is much greater than that of the lighter domestic grades and, therefore, the equipment required for satisfactory storage, pumping; and combustion differs greatly from, that used in the typical domestic oil-burning system. - Both the initial cost and the operating cost of an oil burning system may be affected materially by the charac teristics of the industrial fuel oil to be used. These charac teristics should, therefore, be given careful consideration when preparing the specifications of the fuel oil for which the system is to be designed. Gassffication of Burners Oil burners are usually classified according to the method used for atomizing the oil as (1) horizontal rotary-cup atomizing, (2) mechanical pressure-atomizing, (3) steamatomizing, and (4) air-atomizing. Horizontal Rotary-Cup Burner In this type of burner, oil is delivered into a horizontal cup that is rotated at high speed. As the thin film of cal is spun from the rim of the cup, it enters a cone of high ve locity primary air where very effective atomization is ob tained. In most applications secondary air for combustion is supplied by natural draft through checkered openings in the floor of the combustion chamber. In some applications, however, the secondary air is admitted through openings surrounding the burner nozzle and may be supplied by forced draft. The rotary-cup burner has been the most popular type in the capacity range from approximately 25 to 500 boiler horsepower. Its principal advantages are that it is a selfcontained integral unit; it is readily adaptable to manual, semi-automatic, or fully-automatic control; and the firing rate may be easily modulated through a wide range while maintaining high combustion efficiencies. These burners are frequently used for firing packaged steam generator units. Mechanical Pressure-Atomizing Burner In this burner oil is atomized by passing it. through a specially designed nozzle under pressures of approximately 100 to 250 psig. The air for combustion may be supplied by either natural or forced draft, and is usually admitted through an air register surrounding the burner nozzle or through checkered openings in the floor of the combustion chamber. This burner is popular for marine service and for large capacity multiple installations. It is not readily adapted to fully automatic operation. Steam-Atomizing Burner High-pressure steam is used in this burner,for atomizing the oil. Oil is delivered to the nozzle at pressures ranging from approximately 5 to 50 psig, and steam at approxi mately 50 to 150 psig is admitted to the nozzle by various methods to assist in the atomization. Combustion air is usu ally supplied by natural draft through checkered openings in the floor of the combustion chamber or through an air register surrounding the nozzle. This burner is relatively low in first cost but is not adapted to fully automatic opera tion or wide variations in firing rate. Air-Atomizing Burner The air-atomizing burner is similar to the steam-atomiz ing type, except that air under pressure instead of steam is used for atomization: The performance characteristics of the two burners are also similar but higher temperature oil is usually required when using air for atomization. STORING AND HANDLING HEAVY FUa OILS Preheating of Heavy Fuel Oils Unlike the lighter grades of fuel oils that can be pumped, atomized, and burned efficiently without prior preheating, the heavier grades of residual fuel oils require conditioning by the application of heat before use. Preheating is employed to reduce the viscosity of the oil so that it can be pumped and atomized property by the burner. The function of the burner is to atomize the oil and mix it thoroughly with the proper amount of air for prompt ignition and efficient com bustion. Hie optimum viscosity will vary from 100 to 450 seconds Saybolt Universal viscosimeter, with the type of burner and is reached at different temperatures for different grades of oil. The range of atomizing viscosity is about as follows for normal grades of oil: Type of Burner Mechanical-Atomizing Steam-Atomizing Rotary-Cup-Atomizing Range of Atomizing Viscosities 100-300 SSU 200-250 SSU 250-450 SSU ` Table 1 lists temperatures needed to bring various oil vis cosities to the proper atomizing levels. These can be used with some variation to suit individual operations. The correct degree of preheat must be used for each grade of oil. Underheating or overheating affects the terminal vis- Table 1 .... Preheating Temperatures to Obtain Suitable Viscosities for Atomizing Vbcettty of OH* 09 Taaperafwe (Fafaenbarf) Required InSSf la SSU Desired SSU Viscosity too ISO 200 300 450 100 100 80 70 61 50 150 120 100 90 77 66 200 13b 110 100 87 75 2i 300 150 128 115 100 88 26 400 160 138 128' 108 96 30 500 170 145 133 115 102 39 750 185 160 147 126 114 50 1000 190 168 155 133 120 60 1200 200 175 160 138 125 75 1500 205 180 168 145 132 100 2000 215 190 175 150 137 115 2500 220 195 182 156 143 135 3000 225 200 187 160 146 145 3500 229 205 190 162 150 160 4000 235 208 194 165 152 170 4500 237 212 197 167 155 190 5000 - 240 215 200 168 157 200 5500 245 218 204 172 160 220 6000 248 220 208 175 162 260 7000 250 225 210 177 165 285 8000 254 227 21i 180 i67 320 9000 258 230 216 183 169 342 10,000 260 235 218 186 171 * BSF -- aaeoada Syt>oit Furoi viscosimeter. SSU ~ venal viacrarimetcr. Smyboit Uni- From Pttd OH Jfoaaal, by Paul F. Schmidt (The ladnstriol Ptcm) I9M, p. 105. Cotama* ter 200and SSOvbcoaity Iran Daria En^ineerm* Carp- 492 CHAPTER 34 1959 cosity and actually interferes with the atomizing process. Underheated oil is too viscous for proper atomization, re sulting in poor combustion, the generation of smoke and soot, and an excessively high oil consumption. Overheated oil, on the other hand, is too fluid for correct atomization and is subject to the same type of poor, operating results as the underheated oil. No. 4 fuel oils, with a maximum viscosity of 125 seconds Saybolt Universal at 100 F, as a rule do not require any preheating before atomization. They are sufficiently fluid at normal ambient temperatures for good burner operation. No. 5 fuel oils are of two types: a light grade having a viscosity ranging between 150 and 200 seconds Saybolt Uni versal, that does not require preheating and hence is known as a cold No. 5; and a heavier grade having a viscosity ranging between 200 and 800 seconds Saybolt Universal, that requires preheating and hence is termed a hot No. 5 oil. No. 6 fuel oils (also known as Bunker C) always require preheating, as their viscosities range from 900 to 10,000 seconds Saybolt Universal (50 seconds to 300 seconds Say bolt Furol). A number of factors affect the selection of a fuel oil pre heating method. The three bade factors are: 1. Type of installation (commercial heating, industrial proc ess, power generating; etc.). 2. Type of operation (automatic, semi-automatic, manual, intermittent, continuous). 3. Type of fuel (No. 5, No. 6, Bunker C). The pour point of an oil is another characteristic that could influence the preheating requirements, especially in areas subject to severe winter temperatures. An oil with a sufficiently high pour point may require preheating and con tinuous circulation at temperatures above its pour point at all stages between storage tank and burner to insure its easy pumpability. Oil specifications should be checked for this characteristic and limitations imposed, if feasible. Otherwise the oil piping system must be designed with this high pour specification in mind. . Four mediums for preheating fuel oil are in common use: steam, hot water, gas, and electricity. ' With steam as the heating medium the beater may be of shell-and-tube (either straight or U-tube) type or the heaters may be of a bayonet type inserted in the oil tank. In a bayonet-type heater an open-end tube is enclosed in a larger tube which has a closed outer end. Steam enters through the inner tube while condensate is drained from the outer tube. A heater of bell-shaped type may also be con nected into the oil suction line at the tank for the purpose of raising the temperature of the oil drawn from the tank. The steam preheating method has several linjitations. Mainly, it is dependent upon continuity of burner operation to keep steam available to prevent viscosities beyond pump- ability. Therefore, its practicability and economy are limited to installations having continuous operation. Another limi tation is that the relatively high temperature of steam may cause changes in the chemical structure of lighter grades of residual fuel oils. To prevent excessively high viscosities in the fuel oil piping, constant oil circulation is maintained or the oil piping is enclosed with steam lines in the same thermal insulation. The economy of the steam preheating method is also dependent on the availability of steam at the pressure and quantity required, and on the distance from boiler to storage tank. The hot water preheating method utilizes equipment simi lar to that used for steam. Because of the possibility that oil may penetrate into the boiler through faulty heat ex changes, some devices have been developed to prevent this condition. Double-transfer heaters and fuel-oil detectors are those most frequently used. Similarly, as with steam, con tinuity of burner operation, or cycling burner operation, is needed to maintain the temperature of the heating medium. Since oil heating is limited by the water temperature in the boiler less transmission and transfer losses, such losses must be taken into account, particularly on installations having a considerable length of oil piping. The indirect gas-fired preheating method is a package ar rangement that uses gas as the primary energy source. It generates its own supply of low-pressure steam in a dosed vapor-condensate cycle. The oil is pumped through the steam oil heater as required to compensate for radiation losses in the oil-circuit lines, whenever pumping action stops. During the layover period, the main boilers and oil burners are entirely inactive. If separate oil transfer pumps are not available, a small circulating oil pump is added to the pack age to provide circulation in the oil lines during the gas firing periods. The electrical preheating method involves use of immer sion heaters plus one of two special arrangements for heating the fuel oil piping. One special arrangement is a beating cable (soil cable or. plastic covered wire) wrapped around the supply line or all oil piping together with a vertical-ele ment immersion heater in the suction pipe in the oil tank. The closeness and evenness of the spiral winding of the cable determine the heat input. The on-off periods are thermo statically controlled. For protection of the heating cable, the temperature of the oil piping has to be limited and usually must not exceed 170 F. Where pipe and oil temperatures permit wrapping of all oil piping, constant oil circulation is not required. The efficiency of this preheating method is lower than for element-immersion or electric-impedance heating because of transfer losses between the heating ele ment and the pipe. The other special arrangement for electrical preheating is a packaged system of electric-impedance heating for all oil piping together with immersion element heating sufficient to heat the oil used. Low-voltage high-amperage alternating current of the 60-cycle frequency is passed through the oil piping itself, generating an even amount of beat in the pipe walls. The majority heating effects are due to hysteresis and eddy currents. When removing oil from unheated storage hot excess oil is returned to blend with cold oil from storage in a special tank unit. Since all oil piping is kept at design temperature, under all conditions of flow or standby, con stant oil circulation or cycle precirculation is- not needed. The thermostatic control of pipe and oil temperature results in fully automatic operation. Oil burners designed for automatic operation on No. 5 or No. 6 oil are generally equipped with thermostatically con trolled electric immersion heaters. The function of a burner- immersion heater is to heat the oil at the rate being burned from the transportation temperature (usually at 120 F level for No. 6 oil) to the temperature required for efficient com bustion. This temperature ranges from 130 F to 220 F, de pending on the grade of fuel oil and design of burner. In oh emergency, the burner-immersion heater may be used alone to heat a modulated, very low quantity of oil for combustion. However, in a normal operation, it functions in conjunction with the primary preheating system. Maintaining Piping and Tank Temperature In using No. 5 and No. 6 oils it is necessary to make spe cial arrangements to keep the oil fluid in the piping at all Automatic Fuel Burning Equipment 493 times and to keep at least a portion of the oil in tiie storage tank fluid as well. The piping may be heated by one or more of the following methods: - 1. Wrapping the supply line with electrically heated tape. 2. Passing a current through the supply line itself. 3. Enclosing the supply line, with a steam or hot water line in the same envelope. - 4. TnfluUtmg the supply line so as to decrease the thermal losses. 5. Setting up a dual system in which the primary preheaters have a capacity greater than the burner requirement and re turning the excess heated oil continually to the fuel oil tank. The oil tn the tank or a portion of it may be heated by one of the following methods: 1. By coils in the bottom of the tank. 2. By hot water coils in the bottom of the tank. 3. By a suction-bell, which is provided with either steam or hot water coils, in the bottom of the tank. 4. By providing a hot-well that extends from the top to the bottom of the tank, and provides enough heated oil to supply the burner under a full load. 5. By submerging an electric preheater in the wall or bottom of the tank. Pipe Sizes for Heavy Oil Table 2 gives recommended good practice pipe sizes for handling No. 5 and No. 6 oils. Oil Storage Tanks and Piping Storage tanks, also the piping and pumping facilities for delivering the oil from the tank to the bumer^are very im portant considerations in the design of an industrial oil burning system. The construction and location of the tank and oil piping are usually subject to local regulations which should always be consulted, and to the standards of the Na tional Board of Fire Underwriters, such as NFBU Pamphlet No. 31. . The size of the storage tank is usually based on the rate at which oil is to be consumed, the space available, method of oil delivery (truck or tank car) and the ease with which deliveries can be made under afl weather, conditions. A mini mum capacity of at least the maximum weekly usage is de sirable. If deliveries are to be made by tank car, the capacity should not be less than 15,000 gal. The 275-gal oil storage tank*is commonly used for domes- tc installations. In most localities it may be installed in base ments without being enclosed. Where a greater storage ca pacity is necessary, local regulations usually permit inside installation of two tanks of 275 gal each in accordance with NBFU Standard* Pamphlet No. 31. . Controls The control of oil-fired equipment is discussed in the sec tion Automatic Control of Fuel-Burning Equipment. GAS-FIRED HEATING EQUIPMENT A gas burner is defined by the American Gas Association as "a device for the final conveyance of the gas, or a mixture of gas and air, to the combustion zone." Burners used for domestic heating are of the atmospheric injection, luminous flame, or power burner types. Because of the ease with which gas fuel may be controlled, automatic gas-fired heating equipment has become very widely used, and is available in a number of types of domes tic gas beating appliances and systems. These may- be clas sified in types designed for central heating plants and those for unit application. Gas-designed units and conversion burners are available for the several kinds of central systems in which gravity and forced warm air furnaces or steam and hot water boilers are used, and for other applications where warm air floor furnaces and room heaters are installed in the space being heated. . - Central Heating Systems . Boilers and furnaces specially designed for gas-firing in corporate design features for obtaining maximum efficiency and performance. Small flue passes to secure good beat trans fer, the use of materials resistant to the corrosive effects of products of. combustion, and draft hoods are notable fea tures. Control equipment includes gas-pressure regulators, automatic pilots, and limit controls designed to protect the appliance and to insure safety of operation. A boiler designed for gas-burning is illustrated in Fig. 14. Gas-designed boilers for hot water or steam heating are available in cast-iron, steel, and non-ferrous metals. The burners are located beneath the sections, and the flue gases pass upwards between the sections to the flue collector. Some boilers are designed to provide domestic hot water through the use of tankless or instantaneous heaters. Warm air furnaces are of two types, gravity and forced Table 2 .... Recommended Minimum Suction and Return Pipe Sizes for Fuel Oil Lines* Pipesixes shown m based on vertical suctico lift not to exceed 10 ft bom bottom cl storage tank to oil pomp. b A suction line length in -- ot 100 linear feet is not recommended for eyrtem* using So. S or No. 9 oil. Where the length is greater a separate pomp should be installed near the storage tank. - . * Equivalent length of pipe includes all honsontal and vertical measured taping plus proper allowance for valves and fittings aa follows: ( ' . Multiply pipe diameter in inches by factor.below to obtain equivalent pipe length in feet. Show -- Factor 3; Tee -- Factor 6; Gale Valve -- Factor 1)4; Globe Valve -- Factor 9. 494 CHAPTER 34 1959 air. The former depends upon a thermal head to provide circulation of air over the heat exchanger and thence directly to the space to be heated, usually through ducts. Most gravity furnaces can be equipped with humidifiers. Forced warm air furnaces utilize a motor-driven blower to circulate air over the heat exchanger and through the ducts. A com mon type is.quite rimflax to Fig. 13 except that gas burners, pilots, controls, and gas pressure regulator are substituted for the oil burner, and a draft hood is attached to the outlet of the furnace. Due to the pressure developed by the blower, ductwork becomes smaller and the location -of the furnace less critical than in gravity systems. Designs of forced air furnaces vary from the conventional types that deliver heated air to overhead ductwork to the downflow types Fig. 14 .... Cos-Fired Boiler boilers, a horizontal single-port burner is utilized. This de sign produces a horizontal flume which strikes a curved baf fle that spreads the flame in & fan shape. Several power burners in domestic sizes are available. These are of gun-burner design and feature small mechanical blowers for supplying all the air required for combustion. These are particularly desirable for Handling restricted flue boilers or furnaces where an atmospheric burner cannot ob tain the desired output. Conversion burners for domestic application are available in sizes ranging from 50,000 to 400,000 Btuh capacity. It should be noted that the American Standard listing Re quirements are limited at present to conversion burners hav ing input capacities up to 400,000 Btuh. Burners of larger capacity, for use in large steel boilers, are usually engineered by a contractor specializing in this type of work, or by the local utility company. They are available in a large number of sizes and types. In some cases the burner may be an as sembly of multiple burner heads filling the entire firebox. For conversion burner installation in boilers requiring more thaw 400,000 Btuh input, reference should be made to the current American Standard Requirements for Installation of Gas Equipment in Large Boilers, ASA Z21.33. Domestic sizes of conversion burners should conform to current American Standard Listing Requirements for Do mestic Gas Conversion Burners, ASA Z21.17. As the success ful and safe performance of a gas conversion burner depends on numerous factors other than those incorporated in such equipment, installations of this kind must be made in strict accordance with current American Standard Requirements for Installation of Domestic Gas Conversion Burners, ASA Z21.S. Also, draft hoods conforming to current American Standard Listing Requirements for Draft Hoods, ASA Z21.12, should be installed (in place of the dampers used with a solid fuel) on all boilers and furnaces converted to bum gas. The A.GA. estimates the output of conversion. burners at 72 percent efficiency. This value is based on aver age installations and average heating equipment perform- . wherein the heated air is delivered at the bottom of the furnace, this latter type being designed for perimeter or radiant-panel heating. Several types of low height horizontal furnaces are available for installation in attics or under floors of unexcavated houses. These furnaces are designed for com pactness. The A.GA. listed output at the boiler nozzle or at the bonnet for forced air furnaces is SO percent of the ap proved input to the burners. The corresponding output for gravity furnaces is 75 percent. Conversion Burners Conversion burners are complete burner and control units designed for installation in existing boilers and fur naces. A typical gas conversion burner is shown in fig. 15. Atmospheric conversion burners may have drilled-port, dotted-port, or single-port burner beads. Single-port types have become increasingly popular in the last few.years due to their simplicity of construction and ease of installation In rectangular or round, drilled and dotted-port burners, baffles of clay or metal are usually used to direct the prod ucts of combustion toward the side walls of the combustion chamber. In single-port burners the flame usually impinges on a horizontal cast-iron, stainless steel, or ceramic flame spreader which directs the products of combustion towards the side walls. For certain applications, particularly wet-base Floor Furnace The floor furnace is. used to supply central heating in mild climates, or for auxiliary heating or heating of single rooms in colder climates. It is used for Hpating first floors, or where beat is required in only one or two rooms. A num ber may be used to provide heat for the entire building where Automatic Fuel Burning Equipment 495 all-rooms are on the ground-floor, thus giving the heating system flexibility. In floor-furnace applications, the heating element, gas piping, and flue vent piping are suspended below the floor, and the only part in the room being heated is the circulating air register which may be of the single type installed in the floor, or of the dual type installed in a partition, and heating two rooms. The A.GA. output rating of floor furnaces is based on an efficiency of 70 percent for the gravity-type and 75 percent for the fan-type unit. Another type of heating appliance is the vented recessed heater which is either a gravity or fan-type appliance de signed for installation in or permanent attachment to a wall, floor, ceiling, or partition. Such beaters may have short stub ducts to conduct heated air to adjacent rooms. They are in stalled primarily in-new homes, usually being plastered into the wall as a permanent part of the building. The AGA. heat output rating is required to be 75 percent of the ap proved heat input to the burners for fan-type units, and 70 percent for gravity-type units. Space Heaters Space heaters are defined as heating units that take the air for combustion from the space being heated. They may be broadly classified as room heaters and units heaters. Room heaters are used for heating single rooms or con necting rooms with good circulation between them and, ex cept for wall-type heaters, they are semi-portable. Un- vented-type room heaters should not be used unless space is properly ventilated to prevent excess moisture and to pro vide sufficient combustion air to prevent formation of car bon monoxide. All types of room heaters are capable of auto matic control, although they are generally controlled manually. When equipped for automatic control, they must have ah automatic pilot as part of the control equipment. Room heaters may be classified as follows: Circulators, vented and unvented, that heat the room mainly by convection, although some have radiants over the burner, with windows in the front to allow some heat by radiation. - ' Radiant heaters, usually unvented, although some vented types are available, have a refractory directly above the burners which is heated to incandescence, and gives off an' appreciable part of its heat in the form of radiant energy. Wall heaters, vented or unvented, are usually a type of radiant heater constructed with sufficient insulation (either solid or circulating air) to prevent overheating of the casing, and are built into a wall with the front flush with the wall surface. Their heat input rating is limited to a maximum of 25,000 Btuh. Although an output rating is not required by A.GA., the efficiency of a vented room heater must be not less than 70 percent when rated above 20,000 Btuh input, and 65 percent when rated at less than 20,000 Btuh input. Unit heaters are used extensively for heating large spaces such as stores, garages, and factories. These heaters consist of a burner, heat exchanger, fan for distributing the air, draft hood, automatic pilot, - and controls for burners and fan. They are usually mounted in an elevated position from which the heated air is directed downward by louvers. Some unit heaters are suspended from the ceiling, and others are free-standing floor units of the heat tower type. Unit heaters are classified for use with, or without, ducts depending on specific A.GA. approval. When connected to ducts they must have sufficient blower capacity to deliver an adequate . sir quantity against the duct resistance. Heat output is re quired to be at least 75 percent of beat input to the burners. Duct furnaces are usually of the unit heater type without the fan, and are used for heating air in gristing duct sys- terns where blowers are provided for moving the air through the system. Duct furnaces are tested for operation at much higher static pressures than are obtained in unit heaters. Combustion Process and Adjustments Most domestic gas burners are of the atmospheric injec tion (Bunsen) type in which primary air is introduced and mixed with the gas in the throat of the miring tube. For normal operation of most atmospheric type burners, 40 to 60 percent of the theoretical air as primary air will give best operation. Slotted-port and ribbon burners may require from 50 to 80 percent primary air for proper operation. The amount of excess air required in practice depends upon several factors, notably: uniformity of air distribution and mixing, direction of gas travel from burner, and the height and temperature of combustion chamber.' With power type burners utilizing motor driven blowers to provide both pri mary and secondary air, the excess air can be closely con trolled while securing proper combustion. Secondary air is drawn into gas appliances by natural draft. As with other fuels, excess secondary air constitutes a loss, and should be reduced to a proper minimum which usually cannot be less than 25 to 35 percent, if the appliance is to meet ASA approval requirements. Yellow flame burners depend upon secondary air, alone, for combustion. ' The flame produced by atmospheric injection burners is non-luminous. Air shutter adjustments for manufactured gas should be made by closing the air shutter until yellow flame tips appear, and then by opening the air shutter to a final position at which the yellow tips just disappear. This type of flame obtains ready ignition from port to port, and also favors quiet flame extinction. When burning natural gas, the air adjustment is generally made to secure as blue a flame as is obtainable without lifting of flames from burner ports. Manufacturers' instructions for burner adjustment should be followed. Gas-designed equipment does not usually incorporate any means for varying the secondary air supply (and hence the ' CO,). The amount of effective opening and baffling is de termined by A.GA. tests and cannot be varied. Gas conver sion burners, however, do incorporate means for controlling secondary air to permit adjustment over a wide range of inputs according to the type of installation encountered. The manufacturer's specific instructions contained in the instal lation manual required to be supplied with each burner should be followed. It is possible through the use of suitable indicators to determine whether carbon monoride is present in flue gases. For safe operation carbon monoxide should not exceed 0.04 percent (air-free basis) when operating at the maximum gas input to the burners. During recent years, the use of fuel gas (natural, manu factured, and liquefied petroleum) has become increasingly popular for heating tourist cabins and motels. Due. largely to tiie intermittent use of such equipment and the fact that so many of the users are entirely unfamiliar with toe fun damentals governing its operation, many special and un usual problems arise. The importance of safeguarding the public interest has prompted some state and city officials to adopt and enforce legislation governing not only the manner in which these appliances are installed but the extent to which they must be equipped with reliable safety devices. 496 CHAPTER 34 1959 for example, connection to an effective flue is mandatory. Furthermore, ail such, heating equipment must incorporate an automatic ignition pilot that will shut off gas supply to the main burner or burners in the event of pilot outage. If liquefied petroleum gas is used, the automatic pilot must cut off all gas supply to the appliance, including the pilot burner, in case the pilot flame becomes extinguished. Rating and Sizing Gas Appliances Input rating for a gas appliance is established by demon strating that the appliance can meet the Approval Require ments of the ASA. The tests are conducted at the A.GA. Testing Laboratories. Output rating is determined from the approved input and a minimum required efficiency stated in the Approval Requirements, and is the heat available at the outlet. Although gas-burning equipment usually is completely automatic, maintaining the temperature of rooms at a pre determined figure, there are some manually controlled in stallations. In order to overcome effectively the starting load and losses in piping, a manually-controlled gas boiler should have an output as much as 100 percent greater than 'the equivalent standard radiation which it is expected to serve. . .. Boilers under thermostatic control, however, are not sub ject to such severe pick-up loads and consequently, it is pos sible to use a lower selection factor. For a gas-fired boiler or furnace under thermostatic control, a factor of 20 to 25 per cent is usually sufficient for pick-up allowance. In those installations, in mild climates where 100 percent outdoor air is used, furnaces should be of larger size in order to provide adequate capacity and quick pickup under in termittent heating conditions. The factor to be allowed for loss of heat from piping will vary somewhat, the proportionate amount of piping in stalled being greater for installations than for large ones. For selection factors to be added to installed radiation under thermostatic control, see Chapter 35. Appliances used for heating with gas should bear the ap proval seal of the A.GA. Testing Laboratories on the manu facturer's nameplate; together with the official input and output ratings. It is not permissible-to operate a gas beating unit above its stated rating. It may be necessary to operate below this rating at elevations above 2000 ft. Installations should be made in accordance with recommendations of the American Gas Association, as shown in current American Standard for Installation of Gas Piping and Appliances in Buildings, ASA Z21.30, and in accordance with local regu lations. Sizing of Gas Piping Piping for gas appliances should be of adequate size, and so installed as to provide a supply of gas sufficient to meet the maximum demand 'without undue loss of pressure be tween the point of supply (the meter) and the burner. The size of gas pipe required depends upon the following: 1. Maximum gas consumption to be provided. ' 2. Length of pipe and number of fittings. 3. Allowable loss in pressure from the outlet of the meter to the burner. ' 4. Specific gravity of the gas. To obtain the cubic feet per hour of gas required by the burner, divide the Btu input rate at which the. burner will be adjusted, by the average Btu heating value per cubic foot of the gas. Capacities of different sizes and lengths of pipe, in cubic feet per hour, with a pressure drop of 0.3 in. of water column for a gas of 0.60 specific gravity, are shown in Table 3. In adopting a 0.3 in. pressure drop, due allowance for an ordi nary number of fittings was made. To convert the values given in Table 3 to capacities for another gas of different specific gravity, multiply the tabular values by the multipliers shown-in Table 4. Pipe capacities for gas flow up to 100,000 cfh for various lengths of pipe are given in Fig. 16 whichis based on a spe cific gravity of 0.60. The capacity at a given pressure loss for a different specific gravity may be obtained by multiply ing Fig. 6 capacities by a multiplier obtained from Table 4. Table 3____Capacity of Gas Piping--Cg Ft Per Hr. (A/ pressure drop of 0.3 m. water. Speoln. gravity = 0.60) Length of Hpe . Ft Xl iron Pipe Site (LPS) inches IK 2 3 4 IS 76 172 345 750 30 52 120 241 535 45 43 99 199 435 60 38 86 173 380 75 90 105 120 77 155 345 70 141 ' 310 65 131 285 120 270 150 109 242 180 100 225 210 92 205 240 190 270 178 300 170 450 140 600 119 1220 850 700 610 545 490 450 420 380 350 320 300 285 270 226 192 2480 1780 1475 1290 1120 1000 920 > 860 780 720 660 620 580 545 450 390 6500 4700 3900 3450 3000 .2700 2450 2300 . 2090 ' 1950 1780 . 1680 1580 1490 1230 1030 13S80 9700 7900 6800 6000 5500 5100 4800 4350 4000 3700 3490 3250 3000 2500 2130 From iisffaw Stamford /nstolfafiVa of Go* Pipinf end Go* Appliance* in Bvddinft, ASA Z2130-18SC 6 38700 27370 23350 19330 17310 15800 14620 13680 12240 11160 10330 9600 9000 8500 7000 6000 8 79000 55850 45600 39500 35300 32250 29850 -27920 25000 22800 21100 19740 18610 17660 14420 12480 Length of Pipe Ft 15 30 45 60 75 90 105 120 ISO 180 210 240 270 300 . 450 600 Automatic Fuel Burning Equipment Tabie 4____Multiplier* for Various Specific Gravities (For Ute Wftfi Table 3 and Fig. 16) Specific Gravity Muftipfier Specific Gravity Multiplier 0.35 0.40 0.45 0.50 0.55 0.60 0.65 0.70 0.75 0.80 0.85 O.90 1.31 1.23. 1.16 1.10 1.04 1.00 0.962 0.926 ' 0.895 0.867 0.841 0.817 1.00 1.10 1.20 1.30 1.40 1.50 1.60 1.70 1.80 1.90 2.00 2.10 0.775 0.740 0.707 0.680 0.655 0.633 0.612 0.594 0.577 0.565 0.547 0.535 COMMERCIAL AND INDUSTRIAL GAS EQUIPMENT No attempt can be made, due to space limitation, to de scribe or classify the varied types of equipment used for commercial and industrial applications. Much of the equip ment utilized is custom built to suit a particular process. Certain standard parts such as venturi and burner head sets, ring burners, proportional mixers, or compressors, are pur chased for assembly in existing equipment, usually by the installer. Furnaces to provide particular atmospheres or for annealing, soaking pits, metal melting, etc. are usually en gineered by industrial gas-equipment manufacturers. Burners utilized in industrial equipment often operate at gas pressures higher than encountered in domestic usage. High-pressure gas provides flexibility of control required 497 in the production of constant temperatures^ In addition, air- gas ratios can be closely maintained under throttling con ditions, and heat liberation per cubic foot of combustion space is considerably greater than can be achieved with lower pressures. A few of the many basic types of burners used are as follows: single-pipe high-pressure, proportional mixing, pre mix, two-pipe high-pressure, and atmospheric. The single-pipe high-pressure burner system utilizes gas delivered to the orifice of a venturi at pressures from 10 to 50 psig. A constant pressure compressor, sometimes remotely placed, is occasionally used to increase the gas pressure. The velocity of the gas issuing from the orifice entrains primary air which is controlled by an air shutter on the venturi tube. An advantage of this system is that when the gas pressure is reduced (lowering the input) the air-gas ratio will remain constant, over a fairly wide range. In the proportional mixing burner, an enclosed type ven turi is used and high-pressure air is delivered through an ori fice. The resulting partial vacuum entrains the gas which is supplied through a zero pressure governor. When the air pressure is reduced, the amount of gas entrained is similarly reduced, thus maintaining a constant air-gas ratio over a wide fuel capacity range. The pre-mix burner system embodies a compressor which mixes air and gas intimately and discharges the mixture through pipes to the burners where it is discharged through orifices and burned. The pre-mix compressor can be re motely installed and the mixture can be closely controlled. The two-pipe high-pressure burner system utilizes both air and gas under pressure, both being delivered through orifices and mixed prior to delivery to the burner. The atmospheric burner system is not commonly used. It consists of a burner supplied with gas at a pressure of 2 Q - FLOW JN CUBIC FEET PER HOUR IOO 1,000 2 5 4 A sI - 2____3 -INCHES OF WATER Bated on Spftzgfoa Friction Factor ond 060 Specific Gravity. To convert for other (pacific gravity m Tabie 4. Fig. 16 .... Flow vs. Pressure Drop for Low Pressure Natural Gas . 498 CHAPTER 34 1959 to 12 in. water. A portion of the air or primary air required for combustion is-entrained from the atmosphere by the stream of gas issuing from an orifice, and the air-gas mixture is delivered through a venturi miring tube to the burner head and parts. About 40 to GO percent of the air required for combustion is in the form of primary air and the re mainder, known as secondary air, is supplied from the air surrounding the flam*, Each system embodies characteristics essential for certain applications. It is important that proper and qualified engi neering authorities be consulted prior to the purchase, in stallation, or operation of industrial gas equipment. FUR BURNING RATES The burning rate for automatic fuel-burning devices is de termined by the gross heat output required of the boiler, or furnace, to carry the net heating load, plus allowances for system losses and pickup. General values for these allowances have been given in preceding text. Detailed information for piping and pickup allowances for steam and hot water sys tems, is given in Chapter 35, and for warm air systems, in Chapter 18. When tiie gross output, operating efficiency, and heat value of the fuel are known, the required rate of burning can be determined by means of Figs. 17, 18, and 19 for the several fuels. As the rate of fuel-burning is directly propor tional to the load for a given efficiency, these charts can be extended by moving the decimal points the same number of digits in both vertical and horizontal scales. The correct fuel-burning rate can be determined directly from the several charts for oil or gas burning installations, as these customarily operate on a strictly intermittent basis. These fuel burning devices usually introduce the fuel at a single fixed rate during the on periods, and this rate should be sufficient to carry the gross load. In the ease of coal stokers, which are usually capable of variable rates of firing, it is desirable to operate at as low a rate as weather condi tions will permit, but the maximum.firing rate of the stoker should be sufficient to carry the gross load. This rate may be determined by the same method as used foT oil or gas. CONTROLS FOR AUTOMATIC FUR-BURNING EQUIPMENT Controls for the automatic fuel-burning equipment de scribed in this chapter are outlined here. The basic require ments for oil burners, gas burners and coal burners (stokers) are included'and the term burner refers to all three types of fuel-burning equipment. Controls for these burners can be classified as operating controls, Omit controls and primary controls. The schematic diagrams shown in Fig. 20 indicate the relationships of the basic components. The power supply may be line voltage for each type of burner. In control sys tems for domestic burners the line voltage may be reduced by means of a transformer for those portions of the circuits indicated by dotted lines. Such transformers- are usually built into the stoker and oil burner primary controls. Control systems for domestic gas burners frequently contain a sepa rate transformer as shown. There are domestic gas burner control systems which obtain their electrical power supply from the conversion of heat to low-voltsge electrical energy, in which case no transformer would be required. As the burner sizes increase, the tendency to use ail line voltage controls increases in each of these general categories. Fig. 17 .... Coal Fuel-Burning Rate Chart Thisdart abated upon.No. 3a0 having* beatcontented 143,400 Btu par *aN loo. If other trades of oil are used multiply the value obtained from thk chart by the fcdkrwint factors: No. 1 oil (139.000 Btu per eaXlon) 1.032; No. 4 oil (144.300 Btu per s*Uoa> 0.992; No. 6 oil 040.000 Btu pergalloa) 0-883; and No. 0 ofl (150,000 Btu per gallon) 0.950. - ' Rg. 18 .... Oil Fuel-Burning Rate Chart* Fig. 19 .... Gas Fuel-Burning Rate Chart stoker os. euo* cas burner (O =* Operating Control P Primary Ceafret 1 = UmH Coafrofl * fig. 20 .... Schematic Diagrams of Some Typical Burner Control Systems ' Automatic Fuel Burning Equipment 499 Operating Controls Operating controls initiate the starting and stopping- of. the burner and on larger burners they usually vary the fuel and air input to the combustion chamber in response to varying load demands. For residential and small commercial heating plants with fuel inputs up to aproximately 500,000 Btuh, the operating controller is usually some form of room thermostat which automatically starts and stops the burner through tiie primary control ea-the limit controls permit. As the size of the heating system increases, the use of a. room thermostat as the operating controller for the burner be- ' comes less common. An insertion thermostat (for furnaces), immersion thermostat (for hot water boilers) or pressure controller (for steam boilers) may be applied as an operat ing controller. Also, such devices as submaster and compen sated controllers (which are reset from outdoor temperature for governing the bonnet temperature in large furnaces or the water temperature in a boiler) come into more frequent use on the larger installations. The still larger burners are usually equipped to vary the rate of fuel and air input in response to varying load demands. Limit Controls limit controls guard against unsafe temperature, pressure or water level to assure that safe conditions prevail for the operation of the burner. Regardless "of the type of fuel burned, draft controls increase combustion efficiencies and reduce flue gas loss by maintaining proper draft conditions at all times. For fuel input requirements above approxi mately 1,000,000 Btuh, some additional factors become common to all types of burners. For example, the draft in the firebox is controlled at a suitable constant for all firing rates, including the off period, by measuring the draft con ditions in the firebox &nH actuating a damper operator to position the damper at the boiler outlet. Where necessary, provision may be made to open the boiler outlet Hamper wide before permitting the burner to start and then "to-re turn this damper to automatic control after the burner has been started. Also, the firing rate of these larger burners is frequently automatically adjustable. Provisions are made for always starting the burner on its low firing rate, with facilities for increasing the firing rate slowly after the burner has been started. It is not recommended and codes seldom permit the use of one and the same -instrument as both an operating controller and a high limit control. In such cases an operating controller will be adjusted to control at the de sired set point while the high limit control will be adjusted to stop the burner at some higher point in the event that the operating controller fails to stopthe burner before the higher shut-off point is reached. For example, to maintain a constant water temperature in a hot water boiler, the operating con troller may be set to stop the burner when the boiler water temperature reaches 180 F. The high limit control should then be set to stop the burner at about 200 F. Various interlocks or limit controls are usually included to assure safe operation of these larger burners. A latcbswitch interlock prevents burner operation if the burner is not in its proper firing position. Another interlock must prove that the burner is in its low-fire position before the burner can be started. Safe draft conditions should be proved before the burner can be started or allowed to run, especially where induced draft fans are involved. A smoke detecting device may sound an alarm and stop the burner if excessive smoke is produced. Also, protection against electrical over loads must be provided. Primary Controls Primary controls provide for the safe start and operating procedure of the burner. They are somewhat different for each of the three types of fuel burners. . 1. Stokers. Stokers are equipped with refueling, or hold- fire, controls. These primary controls cause the stoker to in termittently feed a predetennined amount of coal during the long off periods of the operating controller to maintain igni tion and' to reduce the possibility of having idle fuel beds damage stoker castings. In some cases the primary control system includes an out-fire feature which stops the feeding of coal into the firebox if the fire goes out. ' -- 2. Oil Burners. Primary controls required for oil burners depend on the size and type of burner. Some of the more common primary controls are discussed in following para graphs a to d. .. a. Domestic oil burners of the vaporizing type usually re quire a primary control that'will (1) meter the correct amount of oil into the burner to maintain the pilot flame; (2) regulate the required amount of oil into the burner for .its high flame operation; and (3) completely shut off.the flow' of oil in the event of a flame failure. b. Domestic oil burners of the pressure-atomizing type require a primary control that will (1) energize the burner motor and electric ignition; (2) test for the establishment of main burner flame and stop the burner and ignition if flame has not been established; (3)- cut off the ignition after a safe burner flame has been established (does not apply to constant ignition type burners); (4) monitor tbe flame con tinuously during burner operation and stop the burner in the event of flame failure (manual reset is necessary follow ing a flame failure lock-out); and (5) stop the burner when either the. operaring controller or limit control requires it. c. Commercial and industrial oil burners of the pressure atomizing type have primary controls that are essentially the same as those outlined for domestic oil burners of the pressure atomizing type. In addition, some models are equipped with a solenoid oil-shut-off valve to provide a pre- * purge period, if desired, and a quick shut-off of the oil flow when the burner is stopped. . . d. Commercial and industrial oil burners of the horizontal rotary-cup type are usually equipped with a more elaborate primary control system. The primary control is often de scribed as a programming combustion safety control. Its most important operations include (1) starting tbe burner upon a call for heat; (2) providing a pre-purge period before activating the gas-electric ignition; (3) proving the presence of proper ignition before permitting the flow of oil to the main burner; (4) proving the presence of a stable main burner Aam* within a predetermined period of time; (5) shutting off the gas-electric ignition after a predetennined length of time has elapsed; (6) monitoring the main burner flame during its entire on period and stopping the burner quickly in the event of a flame failure (it is usually required that the flow of oil through the burner be stopped within four seconds following a flame failure); (7) stopping the flow of oil through the burner when either the operating controller or a limit control requires it; (8) operating the burner for a predetermined length of time after the main fuel valve has been closed; and (9) locking out on a flame failure shutdown (the programming control then must be manually reset prior to a restart). When steam-, air-, or mechanical-atomizing burners are 500 CHAPTER 34 1959 automatically controlled, their sequence of control is similar to that described for horizontal rotary-cup burners. 3. Gas Burners. Some of the more common primary con trols for gas burners are as follows. ' a. Domestic gas burners of the atmospheric type require a primary control, to insure safe starting and operating con ditions, which will (1) prevent opening of the gas . valve unless the pilot is operating properly, and (2) stop the flow of gas through the burner if safe ignition conditions do not prevail- at all times. . b. Commercial and industrial gas burners of the atmos pheric type require a primary control whose function is similar to that for domestic sizes of these burners except in the rate of response to a" pilot flame failure. The pilot flame burns constantly and, in general, the primary control system will (1) ensure operation only when ignition of the main burner will be safe; (2) start and stop the main burner when required to do so by either the operating controller or a limit control; and (3) close the safety shut-off valve in the gas 'supply line to the burner upon a flame failure or an electrical power failure. c. Commercial and industrial gas burners of the power type equipped with electric ignition require a primary control whose most important operations include: (1) starting the burner" motor upon a call for beat by the oper ating control; (2) providing a prepurge period before ac tivating the gas-electric ignition; (3) proving the presence of proper ignition before allowing gas to flow to the main burner or shutting off the electric ignitor; (4) closing the safety shut-off valve in the event of a flame failure (it is usually required that the flow of gas be stopped within four seconds following a flame failure); (5) stopping the burner when either'an operating controller or a limit control re quires it; and (6) locking out on a flame failure shut-down (the programming control then must be manually reset prior to a restart). . REFERENCES 1 Domestic Burners far Pennsylvania Anthracite (Under feed Type) (U. 8. Department of Commerce, National Bureau of Standards Commercial Standard No. CS48-40). 'Industry standards, recommended practices, in formation (Stoker Manufacturers Association Manual, Stoker Manufacturers Association). : . 'Code for determination of rated capacities of anthracite underfeed stokers; adopted June 1, 1944, and Code for deter mination of rated capacities of bituminous underfeed stokers, adopted May 3, 1944 (Stoker Manufacturers Association Man ual, Stoker Manufacturers Association). * Automatic Mechanical Draft Oil Burners Designed for Domestic Installations (U. S. Department of Commerce, Na tional Bureau of Standards Commercial Standard No. CS75- 42). Phte Connected Oil Burning Space' Heaters Equipped with Vaporising Pot Type Burners (U. S. Department of Com merce, National Bureau of Standards Commercial Standard No. CSlOl-43). Warm-Air Furnaces Equipped with Vaporising Pot-Type Oil Burners (U. S. Department of Commerce, Na tional Bureau of Standards Commercial Standard No. CS104- 46). Oil-Bumxng Floor Furnaces Equipped with Vaporising Pot-Type Burners (U. S. Department of Commerce, National Bureau of Standards Commercial Standard No. CS113-44). ' BIBLIOGRAPHY A. J. Johnson: Performance expectancy of domestic under feed stokers for anthracite (AIMS Transactions, Vol 119 1936). ' R. A. Sherman, E. R. Kaiser, and H. R. Limbacher: The Re lation of the Sise of Bituminous Coals to Their Performance on Small Underfeed Stokers--Burning Tests on Four Typical Coals (Bituminous Coal Research,- Inc., Technical Report -No. 1--Part II, July 1937). J. A. Moyer: Oil Fuels and Burners (McGraw-Hill Book'Co- New York). H. F. Tapp: Handbook of Oil Burning (American Oil Burner Association, superseded by OHI). - F. H. Faust and G. T. Kaufman (eds.): Handbook of Oil Burning (Oil Heat Institute of America). . C. H. Burkhardt: Domestic Oil Burners, Installation and Servicing (McGraw-Hill Book Co- New York). A. H. Senner: A Study of the Oil Burner as Applied to Do mestic Heating (U. S. Department of Agriculture Technical Bulletin 109). - R. J. Bender: Progress in domestic oil heating (Mechanical Engineering, October 1942). - L. E. Seeley and E. J. Tavanlar: ASHVE Ressabch Repost No. 907--Study of performance characteristics of oil burners and low pressure heating boilers (ASHVE Teaksections, VoL 37, 1931, p. 617). L. E. Seeley and J. H. Powers: ASHVE Reseabch Report No. 925--A study of intermittent operation of oil burners (ASHVE TaANSAcnoNS, Vol. 38, 1932, p. 317). L. E. Seeley, J. H. Powers, and E. J. Tavanlar: Air supply and its effect on performance of oil burners and heating boilers (ASHVE Transactions, Vol. 39, 1933, p. 75). L. E. Seeley and E. J. Tavanlar: Study of fuel burning rates and power requirements of oil burners in relation to excess air (ASHVE Transactions, Vol. 40,1934, p. 319). D. W. Nelson: Oil burning in residences (ASHVE Trans actions, Vol. 41, 1935, p. 355). . . R. C- Cross and W. R. Lyman: A study of oil-fired heating boilers (Heating and Ventilating, October 1931). Gaseous Fuels (American Gas Association). .- . Comfort Healing (American Gas Asociation). American Standard Approval Requirements for. Central House Heating Gas Appliances (American Standards Associa tion, ASA Z2U3). Steam and Hot Water Boilers (Vol. I, Z21,13.1-1956 with ad denda Z21.13.1a-1957). Gravity and Forced Air Central Furnaces (Vol. II, Z21.13.2- 1956 frith addenda Z21.132a-1957). .. Gravity and Fan Type Floor Furnaces (Vol. HI, Z21.133-1956 with addenda Z21.133a-1957). ' .* Gravity and Pan Type Vented Recessed Heaters (Vol. IV, Z21.13.4-1955 with addenda Z21.13.4a-1956 and Z21.13.4b- 1957). - American Standard Requirements for Installation of Do mestic Gas Conversion Burners (American Standards Associa tion, Z213-1948). . . . - American - Standard Requirements for Installation of Gas Equipment m Large Boilers (American Standards Association, Z2133-1950). ' ` American Standard for Installation of Gas Piping and Gas Appliances in Buildings (American Standards Association, Z2130-1954). American Standard Approval Requirements for Gas Ural Heaters (ASA Z2U6-1957). American Standard Approval Requirements for Gas-Fired Duct Furnaces (ASA Z2134-1955, with addenda Z2134a-1956 and addenda Z2134b-1957). American Standard Approval Requirements for Gas-Fired Room Heaters (ASA Z21.11-1956, with addenda Z21.11a-1957). A.G-A. Industrial Gas School Lectures (American Gas As sociation, 1951). ' J. D. Keller: Radiant gas burners (A.QA. Sales Conference, American Gas Association, 1949). W. Trinks: Industrial Furnaces (Vol. 1 and 2, John Wiley & Sons, New York, 1944). R. C. Cros: A method for determining fuel burning rates in heating boilers fired by automatic devices (Heating and Venti lating, January 1932).' R. A. Sherman and R. C. Cross: Heat losses and efficiencies of fuels in residential heating (ASHVE Transactions, VoL 43, 1937, p. 185). - CHAPTER 35 HEATING BOILERS, FURNACES, SPACE HEATERS BORERS; Construction, Types, Design Considerations, Rating and Testing Codes, Efficiency, Rating, Selection, Space limitations. Connections and Fittings, Erection, Operation and Maintenance. FURNACES: Types, Materials end Construction, Ratings, Testing and Rating Codes, Efficiency, Design Considerations, Humidification Equipment. SPACE HEATERS: Types: Solid Fuel, Oil, Gas,- Materials and Construction, Testing and Rating, D^ign Considerations, Installation ' N presenting the subject of Boilers, Furnaces, and Space I Heaters this chapter is divided into three parts; the first dealing with boilers, the second treating warm air furnaces, and the third covering space, heaters. ' HEATING BOILERS Steam and hot water boilers for low-pressure heating ore built of steel or cast iron in a wide variety of types and rises, many of which are illustrated in the Catalog Data Section. The nationally recognized code governing the construction of low-pressure steel and cast-iron heating boilers is the ASME Boiler Construction Code for Low Pressure Heating Boilers. Some states and municipalities have their own codes which apply locally, but these are usually patterned after the ASME Code. . The maximum allowable working pressures are limited by the ASME Code for Low Pressure Heating Boilers to 15 pri for steam and 160 pri for hot water heating boilers, with a maximum temperature limitation of 250 F. Hot water boilers are generally designed for a working pressure of 30 priknd may be supplied for higher working pressures, for either heat ing purposes or for. hot water supply, only when designed, tested, and stamped for the higher pressure. - TYPES OF HEATING BOILERS Heating boilers are classified in a number of different ways, such as: " . - . . 1. According to materials of construction. These are steel and cast iron. Very few honferrous boilers are made. * ' . 2. According to the fuels for which the boilers are designed. These are coal, hand-fired or stoker-fired; oil; gas; or wood. Some boilers are designed specifically for one fuel, but many boilers are designed for more than one fuel. . 3. According' to the specific purpose or application for which the boiler is used, such as space heating or domestic hot water supply. ' 4. According to the design or construction of the boiler such as sectional, round, fire-tube, water-tube, magazine-feed, Scotch, etc. Cast-Iron Boilers Cast-Iron boilers are generally classified as: 1. Square or rectangular boilers with vertical sections and rec tangular grates, commonly known as sectional boilers. 2. Round boilers with horizontal pancake sections and circu lar grates. Cast-iron boilers are usually shipped in sections, and as sembled at the place of installation. However, some small boilers are shipped factory assembled. In the majority of boilers the sections are assembled with push nipples and tie rods but external headers and screw nipples are also used successfully. Many sectional boilers are provided with large push nipples at top to permit the circulation of water be tween adjacent sections, at both the water line and bottom of the boiler, which is necessary to enable the use of ah in direct water heater with the boiler for summer-winter hot water supply. Round and sectional boilers may be increased in size by the addition of sections and corresponding plate work. ' Small sectional type boilers are available with wet-base construction, wherein the ashpit or combustion chamber rides and bottom are surrounded by extensions of .the water legs of the boiler sections, and thus ho separate base.is required. This type of construction permits the boiler to be set directly on a wood or composition floor without danger of fire. The wet-base also provides some additional heating surface. Capacities of cast-iron boilers range generally from capaci ties required for small residences up to about 12,000 sq' ft of steam radiation but boilers are made with capacities up to approximately 32,000 sq ft EDR (steam). . Steel Boilers . Steel boilers may be of the fire-tube type, in which the gases of combustion pass through the tubes and the boiler water circulates around them, or of the water-tube type, in which the gases circulate around the tubes'and the water passes through them. Either the fire-tube or water-tube type may be designed with integral water-jacketed furnaces, or ar ranged for refractory lined brick or refractory lined-jacketed furnaces. Those with integral water-jacketed furnaces are called portable firebox boilers, and are the most commonly used type. They are usually shipped in one piece, ready for piping connections. Refractory furnaces are usually installed, in refractory lined furnace boilers after they are set in place. Capacities of steel boilers range from those required for small residences up to about 50,000 sq ft EDR (steam). Boilers for Special Applications One of these is known as the magazine-feed boiler devel oped for the burning of small sizes of anthracite and coke, and has a large fuel carrying capacity, which results in longer firing periods t-h-m would be the case with the standard types burning coal of buckwheat size. Special attention must be given to proper chimney sizes and connections in order to in sure adequate draft. Boilers for hot water supply are classified as direct, if the water heated passes through the boiler, and as indirect, if 502 CHAPTER 35 1959 Guide the water heated does not come in contact with the water or steam in the boiler. Direct heaters are built to operate at the pressures found in city supply mains, and are tested at pressures from 200 to 300 psig. Hie life of direct heaters depends almost entirely on the scale-forming properties of the water supplied and the temperatures maintained. If low water temperatures are maintained, the life of the heater will be much longer due to decreased scale formation and minimised corrosion. Direct ' water heaters in some cases are designed to bum refuse and - garbage. '. ... . Indirect heaters generally consist of steam boilers in con nection with heat exchangers of the coil or tube types which transmit the heat from the steam to die water. This type of installation has the following advantages: increases boiler efficiency and reduces stack temperature, but increases the draft loss through the boiler. Heat-Transfer Rate Practical average overall heat transfer rates, expressed in Btu absorbed per square foot of surface per hour, will aver age about 3300 for hand-fired boilers, and 4000 for mechani cally-fired boilers when operating at design load. When me chanically-fired boilers are operating at maximum load, as defined in this chapter -under heading Selection of Boilers, these values will min between 5000 and 6000. Boilers operating under favorable conditions at these heat transfer rates, will give exit gas temperatures that are considered consistent with good practice, although there are boilers which have high efficiencies and also operate at higher transmission rates. 1. The boiler operates at low pressure. 2. Hie boiler is protected from scale and corrosion. 3. The scale is formed in the heat exchanger in which the parts to which the scale is attached can be cleaned or replaced- The accumulation of scale does not affect efficiency, although it will affect the capacity of the heat exchanger. 4. Discoloration of water may be prevented il the water sup ply comes in contact with only nonferrous met&L Where a steam or a forced circulation hot water heating system is installed, the domestic hot water may be heated by an indirect heater attached to the boiler. For most satisfac tory performance in the steam system, this heater is placed just below the water line of the boiler. In a forced circulation hot water system, it should be located as high as practicable with respect to the boiler. - BOILER DESIGN CONSIDERATIONS. Furnace Design .' - Good efficiency and proper boiler performance are depend ent on correct furnace design. There must be sufficient vol ume for burning the particular fuel which is used, and m^ns to obtain a thorough mixing of air and gases at a high tem perature and at a velocity, low enough to permit complete . combustion of all the volatiles. For hand-fired boilers, the furnace volume should be large enough to hold sufficient fuel for reasonably long firing periods. (See Chapters 33 and 34.) Heating Surface Boiler heating surface is that portion of the surface of the heat transfer apparatus in contact with the fluid being heated on one side and the gas or refractory being cooled on the other side. Heating surface on which the fire shines, is known as direct or radiant surface, and that in contact with hot gases only, as indirect or convection surface. The amount of surface, its distribution, and the temperatures on either side thereof, influence the capacity of any boiler. Direct heating surface is more valuable than indirect per square foot because it is subjected to a higher temperature and also, in the case of solid fuel, because it is in position to receive the full radiant energy of the fuel bed. The effectiveness of the heating surface depends on its cleanliness, its location in the boiler, and the shape of the gas passages. The area of the gas passages must not be so email as to cause excessive resistance to the flow of gases, where natural draft is employed. Inserting baffles so that the beat ing surface is arranged in series with respect to the gas flow, RATING AND TESTING CODES Heating boilers are usually rated according to codes de veloped by the Steel Boiler Institute, the Institute of Boiler and Radiator Manufacturers, the American Gas Association, and the Mechanical Contractors Association of America, whose test codes have been prepared specifically for the pur pose of obtaining information required for establishing ac ceptable ratings. The various current rating and testing codes will be discussed in following paragraphs in which limitations, methods of application, and resulting ratings will be de scribed. . The Steel Boiler Institute has adopted a rating code for boilers designated Table I Steel Boilers, Table 2 Steel Boilers, and Table S Steel Boilers, and a testing code for OH-fired Table 2 and Table S Steel Boilers (SBI Rating Code, Eighth Edition, February 1958). Tables 1, 2, and 3 of this chapter show the SBI Gross Outputs and Net Ratings of these three classes of boilers. The Table I boilers (defined as those having 129 to 3571 . sq ft of heating surface and formerly designated as Com mercial boilers) are rated in square feet EDR design load (steam) on the basis of heating surface with limitations set for grate area, furnace volume, and furnace height. The Table 2 boilers (defined as'those having not more than 294 sq ft of heating surface and formerly designated-as Residential boilers) are rated'on the hssis of heating surface with ratings confirmed by test. The Table S boilers (defined ss having no limits of minimum heating surface or furnace volume, and having Gross Outputs and Net Ratings listed in Table 3) are rated on the basis of performance under the provisions of Section III, Part 2, of the SBI Rating Code. The minimum stack area dimensions to be cataloged for Table S boilers are shown in Table 4. Required stack heights are found in the catalogs of the manufacturers, ' Stoker-fired and gas-fired Table 2 boilers are rated (SBI Net Rating) not In excess of the oil-fired rating. Hand-fired Table 2 boilers are rated (SBI Net Rating) not greater than fourteen times the heating surface. The Institute of Boiler and Radiator Manufacturers Ha* adopted a code1 for rating cast-iron beating boilers, based upon performance obtained under controlled test conditions. This code applies to all sectional cast-iron heating boilers ex cept those of magazine-feed type. The Gross I -- B = R Output is obtained by test, and is subject to certain limiting factors. For hand-fired boilers, the number of boilers of a series to be tested, the minimum over all efficiency, the minimum time limit (the time an Available Fuel Charge will last when burned at a rate which will pro duce the Gross I -- B = R Output), the chimney area and Table 1 . . . . SBI Ratings fo r Table 1 Steel Boilers Heating Boilers, Furnaces, Space Heaters 4.000 6.000 6,000 7,000 2,600 3,000 3,600 9.330 1,400 18.1 11.330 1 1,700 1 20.5 13.330 2,000 22.5 33,330 63,300 37,600 60,000 41,670 66,700 16,700 20,000 23,330 3,750 1 6,000 900 4,170 6,670 1,000 , 6,000 8,000 : 1,200 4,000 4,670 6,330 SBI Rating IPS In. 2f sf !.= ii S V) C CO !i S=L K 7.9 8.9 9.7 -*< oooo *> to co V * + OO OO 00 aococn S3 8S ^efieso ' S 9 n o o o e* e* e* SS5! ooo 9SS Q CB - 33 ill 000*01 000*6 000*8 u 5> li Z 2,170 1,830 1,600 l *6 6 toit (0 I 1 I 3vSS ooo aS 2 si I oc55ooteo lo--o ei" n v 4,800 6,600 6,400 2,600 2,920 3,330 1,680 1 2,040 2,400 6,830 7,080 8,330 10,420 12,600 14,680 32.000 40.000 48.000 66.000 4,800 6,000 7,200 8,400 liii ssS5 oooo s 3838 sod 64.000 72.000 80.000 12,500 20,000 .3,000 15,000 i 24.000 , 3,600 17,600 28.000 4,200 < 7,200 8,000 | 9,600 000*91 `009 e i 1 002*11 40.000 45.000 60.000 20,000 26,000 30.000 35.000 500 7.000 608 ' 8,600 715 10.000 216 3.000 250 | 3,600 286 4.000 2,600 2,200 1,800 | g v*- *o 893 1,072 1,250 . !i - : li*a o E sl 5 -- E, ^ I 5 Sc E4 s w 228 26.1 30.4 34.8 ** 888 gs S38 1 --T c* ci * 9$ 9SSS SNS 346.9 390-3 433.6 14,400 16,200 18,000 8,400 12,600 303.6 7,200 10,800 260.3 9,000 216.9 1 4,800 7,200 173.5 60.8 ! 73.8 . 86.8 108.6 | 130.2 ! 161.8 1 1,080 1,260 1,440 Mil ssl 111 -- -- ei" ci co co o 28.000 1 24.000 3,600 20,000 | 3,000 s 5 813 S -* > CO 1 2,880 3,520 .4,100 I 3 cr 5> Z 1 111 V *o co 1,800 2,200 2,600 I er 2 M to 3.000 3,600 4.000 720 1 840 960 4,500 7,200 6,000 1 8,000 1 6,000 9,600 | 1,080 1,200 1,440 III HI 7.000 8,600 ! 10.000 1 4,200- 32.000 40.000 48.000 56.000 6,000 1 64.000 72.000 80.000 9,600 10,800 12,000 81 9 5S. ! i 20,000 25.000 30.000 36.000 | 1,313 1,459 1,760 | 876 1,020 1,166 626 643 768 %JS 5 : 11,657 13,114 14,670 6,830 7,286 8,743 10,200 .i 124,280 3,463 12,500 !29,150 4,373 15,000 j 34,000 , 5,100 17,600 77,710 87,420 97,140 24,290 38,860 30,360 48,750 1 36,430 68,280 42,600 68,000 8,500 13,600 2,040 10,330 116,260 | 2,479 12,160 19,440 2,916 6,840 6,800 7,770 >BI Rating Si 5 88S Q <3 o n Vo sEi 2,190 .2,680 3,160 ss 3,660 4,260 4,860 5,470 6,080 7,290 48,570 64,640 00,710 3eS 503 3 B a 3 -s I 3 ? s 2 d 3 2 1 15,180 18,220 21,250 504 CHAPTER 35 1959 Guide Table 2 ....SBI Net Rating Data for Tab/e 2 Steel Boilers--Oil-fired* Table 3 ... - SBI Gross Output and SBI Net Rating Data for Table 3 Steel Boilers SBI Net Rating Steam SqFt 0) Btuh 12) Water Btvh (3) SBI Grots Output Bhd> Minimum Minimum Furnace Heating Volume C Ft SqFI (4) (5) 16) 275 320 400 550 700 900 1100 66,000 77,000 96,000 132,000 168,000 216,000 264,000 74,000 87,000 108,000 149,000 189,000 243,000 297,000 99,000 115,000 144,000 198,000 252,000 324,000 396,000 2.5 2.9 3.6 5.0 6.4 8.2 10.0 16 19 24 32 41 53 65 l&O 1500 1800 2200 2600 3000 3500 4000 4500 5000 312,000 360,000 432,000 351,000 405,000 486,000 468,000 540,000 648,000 528,000 624,000 720,000 594,000 792,000 702,000 936,000 810,000 1,080,000 ' 840,000 960,000 1,080,000 1,200,000 945,000 1,080,000 1,215,000 1,350,000 1,260,000 1,440,000 1,620,000 1,800,000 n.8 13.6 16.4 20.0 23.6 27.3 31.8 36.3 40.9 45.4 77 88 106 129 153 177 206 236 265 294 * Stoker-firedand Gas-Fired SBI Net Rating notcreater than oil-fired rating. Hand-Fired Net SRI Rating (Steam) not greater than 14 time* the square feet of surface. height, and the draft in the stack are all subject to the limits established in the code. Tests are run using anthracite .coal of standard specification. Bituminous coal and coke ratings are the same as for anthracite. For automatically-fired boilers, the number of boilers of a series to be tested, the flue gas temperature and analysis, the minimum overall efficiency, the draft loss through the boiler, and the heat, release in the combustion chamber are sub jected to limitation by the code.1 Oil-flred boiler ratings are established by testa using gun-type oil burners and commer cial grade No. 2 fuel oil. Stoker-fired ratings are based on the Gross I = B = R Output obtained by oil-fired tests. Gas- fired ratings for boilers having gross outputs greater than 300,000 Btu per hour, where no A.GA. Rating is published, are based on the Gross I = B = R Output obtained by oil- fired tests. Gas-fired ratings for boilers having gross outputs less than 300,000 Btu per hour, where no A.GA. Rating is published, are established by gas-fired tests with atmospheric, single-port-type burners using natural or manufactured gas or a mixture of these two gases. The A.GA. Output Rating of a gas-designed boiler may be used in determining the Net l = B = R Rating. . The Net / = B -- R Rating is determined from the Gross I = B = R Output by applying specified Piping and Pickup Factors which range from 2.36 to 1.40 for hand-fired boilers, and from 1.56 to 1.288 for automatically-fired steam boilers, and from 1.333 to 1288 for automatically-fired hot water boilers. In all cases, the factor decreases as the boiler size in creases. Table 5 is abstracted from the 19511 = B = R Boiler Rating Tables in the.code and illustrates the relationship be tween Net I = B = R Rating and Gross 1 ~ B -- R Output. The American Gas Association rates gas designed boilers at 80 percent of the A.GA. Input Rating. These ratings are SBI Grom Output BM> 99,000 115.000 144.000 198.000 252.000 324.000 396.000 504.000 648.000 792,000 1,008,000 1,260,000 1.512.000 1.800.000 SBI Net Rating* Water BhA 74.000 87.000 108.000 149.000 189.000 243.000 297.000 378.000 488.000 594.000 756.000 945.000 1.134.000 1.350.000 Steam Btuh 66,000 77-,000 96,000 132.000 168.000 216,000 264.000 336.000 432.000 528.000 672.000 840.000 1,008,000 1,200,000 Steam Sq Ft 275.000 320.000 400.000 550.000 700.000 900.000 1,100,000 . 1.400.000 1.800.000 2,200,000 2,800,000 3,500,000 4,200,000 5,000,000 Table 4 .... Minimum Stack Dimensions for Table 3 Oil-Burning Boilers and Boiler-Burner Units Rectangular Round Firing Rate Not Over Gph 2.1 3.5 5.3 7.7 11.5 15.0 21.0 26.0 Nominal Dimension* lad.- 8X8 8 X 12 12 X 12 12 X 16 16 X 16 16 X 20 20 X 20 20 X 24 Inside Dimensions at Liner lnd"* Firing Rate Not Over Gph Inside Ola of Liner Inches 6Yg X 6H 6tf X 10K mx m 1.3 1.8 2.5 6 7 8 9H*X 13M 1314 X 13K 13 X 17 4.7 5.6 7.0 10 11 12 16H x 16M 16M X 20H 12.0 19.0 15 18 determined by performance tests' described in the A.GA. Approval Requirements for Central Heating Appliances. The Mechanical Contractors Association of America has adopted a method, based on their physical characteristics, for rating boilers that are not rated in accordance with the SBI or I = B = R Codes. Ratings are expressed on a Net Load basis in square feet of steam radiation. The MCAA has also adopted a Testing and Rating Code for Boiler-Burner Units* The purpose of this Code is to pro vide a basis of rating commercial sizes of steel heating boilerburner units fired with oil or gas fuel. This code allows a higher rating than is permissible under the SBI Code. A ' gross output is established with certain limiting factors ap plying to flue gas temperature, carbon dioxide, efficiency, and quality of steam. This output is divided by 1.5 to determine the net rating. BOILER EFFICIENCY The term efficiency, as used for guarantee of boiler per formance, is usually construed as follows: 1. Solid Fuels. The efficiency of the boiler alone is the ratio of the heat absorbed by the water and steam in the boiler per Heating Boilers, Furnaces, Space Heaters 505 labie 5....i = B = R Boiler Ruling Table* Aufomatic-Rred ' Netl-B-R Rating Output Steem and water Steam Piping and Pickup Factor MBh MBh Sq Ft 123 4 57 24 100 2.360 218 96 400 2.268 359 168 700 2.139 489 240 1000 2.039 614 312 1300 1.967 735 384 1600 1.914 854 970 1083 1192 1298 1401 456 1900 1.872 528 2200 1.837 600 2500 1.805 672 2800 1.774 744 3100 1.744 816 3400 1.717 1502 1599 1726 1849 1968 2086 888 960 1056 1152 1248 1344 3700 4000 4400 4800 5200 5600 1.091 1.666 1.634 1.605 .1.577 1.552 2197 2307 2415 2470 2805 2738 1440 1536 1632 1680 1800 1920 6000 6400 6800 7000 7500 8000 1.526 1.502 1.482 1.470 1.447 1.426 2874 3024 3192 3360 4032 4704 2040 2160 2280 2400 2880 3360 8500 9000 9500 10000 12000 14000 1.409 1.400 1.400 1.400 1.400 1/400 5376 6048 6720 3840 4320 4800 16000 18000 .20000 1.400 1.400 1.400 Time Avail- Fuel wn Last, Maximum Height* Minimum Area6 Gross Output Hr 5 7.50 6.32 5.73 5.32 4.99 4.73 4.49 4.34 4.24 4.15 4.07 4.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00 Ft 6 29.0 36.5 42.0 46.0 49.0 52.0 54.5 56.5 59.0 61.0 63.0 64.5 66.5 68.0 70.0 71.5 73.0 74.5 76.0 77.5 79.0 79.5 81.5 83.0 85.0 87.0 89.0 91.5 99.0 106.5 112.5 118.0 120.0 Sq la. 7 MBh 6 50 37 50 146 54 251 82 352 no 451 135 547 160 642 185 736 207 829 231 920 253 1011 275 1101 296 1189 315 1278 337 1394 358 1509 376 1624 393 1739 409 1858 425 1978 433 2102 446 2164 464 2318 481 2473 497 _ 515 535 555 634 712 2628 2782 2937 3091 3709 4328 789 4946 863 5564 900 6182 Net 1 = B -- R Rating Water Steam Piping and Pickup Factor Water Steam Minimum Maximum Stack AOowoble Area6 Draft loo MBh 9 28 no 188 264 338 410 482 552 622 690 758 828 892 ' 960 1056 1152 1248 1344 1440 1536 1632 1680 1800 1920 2040 2160 2280 2400 2880 3360 3840 4320 4800 MBh Sq Ft 10 11 12 24 100 1.333 96 400 1.333 168 700 1.333 240 1000 1.333 312 1300 1.333 384 1600 1.333 456 1900 1.333 528 2200 1.333 600 2500 1.333 672 2800 1.333 744 3100 1.333 816 3400 1.333 888 960 1056 1152 1248 1344 3700 4000 4400 4800 5200 5600 1.333 1.331 1.320 1.310 1.301 1.294 1440 1536 1632 1680 1800 1920 6000 6400 6800 7000 7500 8000 1.290 1.288 1.288 1.288 1.288 1.288 2040 2160 2280 2400 2880 3360 8500 9000 9500 10000 12000 14000 1.288 1.288 1.288 1.288 1.288 1.288 3840 4320 4800 16000 18000 20000 1.288 1.288 1.288 13 1.560 1.525 1.492 1.466 1.444 1.424 1.408 1.394 1.382 1.369 1.359 1.349 1.339 1.331 1.320 1.310 1.301 1.294 1.290 1.288 1.288 1.288 1.288 1.288 1.288 1.288 1.288 1.288 1.288 1.288 1.288 1.288 1.288 Sq In. 14 50 50 50 52 73 95 115 135 155 173 192 211 230 249 274 318 339 359 377 395 405 426 446 467 486 504 596 668 740 810 877 In. W.G.6 15 0.044 0.058 0.072 0.084 0.096 0.108 0.118 0-130 0.141 0.152 0.162 0.172 0.183 0-192 0.206 * ExtractedIrom Rating Table in 19SI edition of / B -- R Teeing end Bating CoS*for Lxc Pressure Coot Iron Heating BeOort. b To bespecified in catalog. * Maximum stack height which may be shown in catalog. pound of combustible burned on the grate, to the calorific value of 1 lb of combustible as fired. The'combined efficiency of boiler, furnace, and grate is the ratio of the heat absorbed by the water and steam in the boiler per pound of fuel as fired, to the calorific value of 1 lb of fuel as fired. 2. Liquid and Gaseous Fuels. The combined efficiency of boiler, furnace, and burner is the ratio of the heat absorbed by the water and steam in the boiler per pound or cubic foot of fuel, to the calorific value of 1 lb or cubic foot of fuel, respec tively. The following efficiencies apply to current designs of boilers operated under favorable conditions at their gross output ratings. Some older boilers, designed primarily for hand fir ing, may have lower efficiencies when automatically-fired. Anthracite, hand-fired................................... 60 to 75 percent Bituminous coal, hand-fired..................., 50 to 65 percent Stoker-fired..................................................... 60 to 75 percent Oil- and gas-fired ...........................................70 to 80 percent Higher efficiencies for hand-fired bituminous coal may be obtained by careful firing of either a regular or a smokeless boiler. RATING OF BOILERS In referring to boiler rating, it is necessary to know the basis on which the rating has been established in order to understand the exact meaning of the term. The following example will illustrate the meaning of three ratings which might be established for the same boiler. Assume that an installation has the following loads deter mined in accordance with the section Selection of Boilers: Net Load............................... \ 1000 sq ft of steam radiation Piping Tax................................. 200 sq ftof steam radiation Design Load.............................. 1200 sq ftof steam radiation Pickup Allowance.................... 240 sq ftof steam radiation Maximum or Gross Load___ 1440 so ft of steam radiation 506 CHAPTER 35 1959 Guide A boiler that is just large enough to carry this system might be said to have a net load rating of 1000 sq ft, a design load rating of 1200 sq ft, or a gross load rating of 1440 sq ft, de pending on the basis on which the boiler is rated. On a net load basis the boiler would be rated 1000 sq ft of steam radiation and would have sufficient excess capacity to supply the normal piping and pickup load. Net I = B = R Ratings, SBI Net Ratings, and Net Load Ratings of the Mechanical Contractors Association of America are estab lished on this bass. . On a design load basis the boiler would be rated 1200 sq ft of steam radiation and would have sufficient excess capacity to supply the pickup load. It would be of adequate size for a system in which the sum of the net load and the piping heat loss did not exceed 1200 sq ft of steam radiation. The SBI Ratings shown in columns 1, 2, 3, 10, 11, and 12 of Table 1 (not to be confused with SBI Net Rating) are established on a design load baas. On a gross output baas of rating, the boiler would be rated 1440 sq ft of steam radiation and would be of adequate size for a system in which the sum of the net load, piping load, and pickup load did not exceed 1440 sq ft of steam radiation. Gross I = B = R Output and A.GA. Ratings are established on a gross output basis. In the determination of boiler ratings, the Gross Output is the quantity of heat available at the boiler nozzle, with the boiler normally insulated and when operating under limita tions stipulated in the code or method by which the boiler is rated. The boiler may be capable of producing a greater nozzle output, but in doing so would exceed some of these limita tions. SRECTION OF BOILERS General Factors The Maximum Load or Gross Load an the boiler is the sum of the four following items. The Design Load is the sum of items 1, 2, and 3. The Net Load is the sum of items 1 and 2. 1. Radiation Load. The estimated heat emission in Btu per hour of the connected radiation (direct, indirect, or forced con vection coils) to be installed. The connected radiation is determined by calculating the heat losses for each room in accordance with data given in Chapters 9, 11, and 12. The sum of the calculated heat loses for all the rooms represents the total required heat emission of the con nected radiation, expressed in Btu per hour. As practically all boilers are now rated on a Btu basis, it is unnecessary to convert the radiation load to square feet of equivalent direct radiation. 2. Hot Water Supply Load. The estimated maximum beat in Btu per hour required to heat water for domestic use. I = B -- R recommends that allowance for hot water supply load be made only for bathrooms in excess of two, as follows: Instantaneous Coil 12,000 Btu per hour, and for Storage Tank installation 120 Btu per (hour) (gallon of fr*nlr capacity). For instantaneous coil installations the boiler capacity mould not be less than required to heat 2 to 3 gal of water, 100 deg per min See also Chapter 56. - 3. Piping Tax. The estimated heat emission in Btu per hour of the piping connecting the radiation and other apparatus to the boiler. As the heating industry as a whole is not entirely agreed upon Eiping tax allowances for different of installutinna it is etter to compute the heat emission from both bare cov ered pipe surface in accordance with data in Chapter 32. In average house beating systems, it is common practice to con sider the piping tax to be equal to 25 percent of the Net Load. In determining Net I = B -- R Ratings from Gross I -- B = R Output, the piping factor allowed varies from 30 percent for small boilers to 12 percent for larger boilers. 4. Warming-Up or Pickup Allowance. The estimated increase in the normal load in Btu per hour caused by the heating up of the cold system. The warming-up allowance represents the load due to heating the boiler and contents to operating temperature, and heating up cold radiators and piping. Other items to be considered in boiler selection are as fol lows: a. Efficiency with hard or soft coal, g*a, or oil firing, as the case may be. b. Grate area with hand-fired coal, or fuel-burning rate with stokers, oil, or gas. ' , c. Combustion space in the furnace. - d. Type of heat liberation, whether continuous or intermit tent, or a combination of both. e. Convenience in firing and cleaning. /. Adaptability to changes in fuel and kind of attention. g. Height of water line. h. Miscellaneous items such as draft available, possibility of future extension, possibility of breakdown, and head room in the boiler room. *. The most economical size of boiler is usually one that is just the right size for the load. Either larger or smaller boilers may be less economical. Cast-Iron Boilers Net load ratings of cast-iron boilers are usually available from manufacturers' catalogs. They may also be obtained conveniently from published tables of I = B = R ratings," or from recommendations of the Mechanical Contractors Asso ciation of America,* and can be used in selection of boilers, unless the heating system contains an unusual amount of bare pipe, or the nature of the connected load is such that the normal allowances for pipe loss and pickup do not apply. In such a case, the selection must be based on the gross output. Steel Heating Boilers SBI catalog ratings, in accordance with the previously mentioned Steel Boiler Institute code, are intended to corre spond with the estimated design load. When the beat gmigsinn of the piping is not known, the net load to be considered for the boiler may be determined from Tables 1 and 2. The differ ence between design load and net load represents an amount which is considered normal for piping loss of the ordinary heating system. ' Boilers with less than 294 sq ft of heating surface and hav ing SBI net ratings (steam) of not more than 5000 sq ft if mechanically-fired and 4120 sq ft if hand-fired, are classified as Table Steel Boilers, formerly Residential boilers. An in sulated Table 2 boiler for oil, gas, or stoker firing may carry a net load expressed in square feet of steam radiation of not more than seventeen times the square feet of heating surface in the boiler, provided the boiler has been tested in accordance with the SBI Code for testing oil-fired steel boilers at output rates of 125,150, and 175 percent of the steam SBI net rating. The SBI net rating for a water boiler, automatically-fired, expressed in Btu per hour, is 270 times the steam SBI net rating in square feet. The net water rating is 12W percent greater than the steam rating because a lower piping and pickup factor is generally required in a water system. The SBI net rating (sq ft steam) for hand-fired Table 2 boilers is not greater than fourteen times the heating surface. If the heat loss from the piping system exceeds 20 percent of the installed radiation, the excess is to be considered as part of the net load. Gross Output ratings for Table 1 and Table 2, as well as for Heiating;Boilers, Furnaces, Space Heaters - 507 Table S (a new'designation) Steel Boilers are shown in the seventh edition of the SBI Rating Code. . Heating Surface and Grate Area Basis Where neither the net load nor gross output ratings based upon performance tests are available, a good general rule for conventionally designed boilers is to provide 1 sq ft of boiler heating surface for each 14 sq ft of equivalent radiation (240 Btu per sq ft) (hr) represented by the design load. This is equivalent to allowing 10 sq ft of boiler heating surface per boiler horsepower. In this case it is assumed that the maxi mum load including the warming-up allowance will be pro vided for by operating the boiler in excess of the 'design load, that is, in excess of the 100 percent rating on a boiler-horse- Toble 6___ Proctico! Combustion Rates for Coal-fired Heating Boilers Operating, at Maximum Load on Natural Draft of From In. to H Hi Water*. Kind of Coot lb of Cool Sq Ft Grot* per (Sq Ft Cnbl (Hr) No. 1 Buckwheat Anthracite Anthracite Pea Anthracite Nut and Larger . Up to 4 5 to 9 10 to 14 15 to 19 20 to 25 Up to 9 10 to 19 20 to 25 . Up to 4 5 to 9 10 to 14 15 to 19 20 to 25 - Up to 4 5 to 14 15 and above 3 3M 4 4K 5 5 5H 6 8 9 10 11 13 9.5" 12 15.5 Steel boiler* usually have MyW combustion rate* far grate af**> ermimiing IS *q ft than those initiated in this table. power basis. SBI ratings for hand firing are based on 10 sq ft of heating surface per boiler horsepower. . '. Due to the wide variation-which.may be encountered in manufacturers' ratings for boilers of approximately the same capacity, it is advisable to check the grate area required for heating boilers burning solid fuel by means of the following formula: * .. H G CXPXE (1) tohere . G n grate area, square feet. H required gross output of the boiler, Btu per hour (see Selection of Boilers) C = desirable combustion rate for fuel selected, pounds of dry coal per (square foot of grate) (hour). (See Table 6.) P = calorific value of fuel, Btu per pound. B -- efficiency of boiler, usually taken aa 0.60. ' Example 1: Determine the grate area for a required gross output of the boiler of 500,000 Btu per hour, a combustion rate of 6 lb per hour, a calorific value of 13,000 Btu per pound, and an efficiency of 60 percent. - 500,000 10.7 sq ft 6 X 13,000 X 0.60 The boiler selected should have a grate area not less than that determined by Equation 1. With small boilers, where it is desired to provide sufficient coal capacity for approximately an eight-hour firing period plus a 20 percent reserve for ig niting a new charge, more grate area may be required depend ing upon the depth of the fuel pot. Gas-Fired Boilers . After determining the net load for the installation, gasdesigned boilers can usually be selected from manufacturers' tables of net load ratings which are based on piping and pickup allowances varying from 56 percent for small steam boilers and 333 percent for small hot water boilers to 28.8 percent for very large boilers. If the piping and pickup load or other factors create an unusual load, a boiler should be selected which has an A.GA. output rating equal to the maxi mum. output required. Detailed recommendations for selec tion of gas designed boilers are given in the A.GA. publica tion, Comfort Heating SPACE LIMITATIONS Boiler rooms should, if possible, be situated at a central point with respect to the building, and should be designed for a maximum of natural light. The space in front of the boilers should be sufficient for firing, stoking, ash removal, and cleaning or renewal of flue tubes, and should be at least 3 ft greater than the length of the tubes. - A space of at least 3 ft should be allowed on at least one side of every boiler for convenience of erection and for ac cessibility to the various dampers, cleanouts, and trimmings. The space at the rear of the boiler should be ample for the chimney connection and for cleanouts. With large boilers the rear clearance should be at least 3 ft in width. The boiler room height should be sufficient for the location of boiler accessories, and for proper installation of piping. In general, the ceiling height for small steam boilers should be at least 3 ft. above the normal boiler water line. With vapor heating, especially, the height above the boiler water line is of vital importance. .- CONNECTIONS AND FITTINGS Steam outlet connections should be the full size of the manufacturers' tappings, in order to keep the velocity of flow through the outlet reasonably low, and to avoid fluctuation of the water line and undue entrainment of moisture, and should extend vertically to the maximum height available above the boiler. A steam velocity in boiler outlets not ex ceeding 25 to 30 fps at maximum load is recommended, .un less data are available to show that a higher velocity is satis factory. See further data on pipe connections to boilers in Chapters 26 and 28 and in the ASMS Boiler Construction Code for Low Pressure Heating Boilers. Where a return header is used on a cast-iron sectional boiler to distribute the condensate to both rear tappings, it is advisable to provide full size plugged tees ingteari of el bows where the branch connections enter the. return tap pings. This aids in cleaning of sludge from the bottom of the boiler sections through the large plugged openings. An equiva- 508 CHAPTER 35 1959 Guide lent cleanout plug should be provided in the case of a.single return connection. Blowoff or drain connection* should be made near the boiler, and so arranged that the entire system may be drained of water by opening the drain cock. In the case of two or more boilers separate blowoff connections must be provided for each boiler, on the boiler side of the stop valve on the main return connection. Water service connections must be provided fo'r both steam and water boilers, for refilling and for the addition of make-up water to boilers. This connection is usually of galvanized steel pipe, and is made to the return main near the boiler or boilers. . ... Fitting connections for pressure gage piping, water gage- connections, and safety valves, should be made in accordance with the ASMS -Boiler Construction Code for Low Pressure Heating Boilers. Smoke Breeching and Chimney Connections. The breech ing or smoke pipe from the boiler outlet to the chimney should be airtight and as short and 'direct as possible, preference being given to long-radius and 45-deg instead of 90-deg bends. The breeching entering a brick chimney should not project beyond the flue lining, and where practicable it should be grouted from the inside of the chimney. A' thimble or sleeve usually is provided where the breeching enters a brick chim ney. . Where a battery of boilers is connected into a breeching, each boiler should be provided with a tight damper. The breeching for a battery of boilers should not be reduced in size as it goes to the more remote-boilers. Good connections made to a good chimney will usually result in a rapid response by the boilers to demands for heat. ERECTION, OPERATION, AND MAINTENANCE The directions of the boiler manufacturer should always be read before the assembly or installation of any boiler is started, even though the contractor may be familiar with the boiler. All joints requiring boiler putty or cement,. which cannot be reached after assembly is complete, must be fin ished as the assembly progresses. . Five precautions that should be taken in. ah installations to prevent damage to -the boiler are: .'- 1. There should be provided proper and convenient drainage connections for use if the boiler is not in operation during freez ing weather. 2. Strains on the boiler, due to movement of piping during expansion, should.be prevented by suitable anchoring of piping, and by proper provision for pipe expansion,and contraction. 3. Direct impingement' of too intense local heat upon any part of the boiler surface, as with oil burners, should be avoided by protecting the surface with firebrick.or other refractory ma terial. '. 4. Condensation in steam systems must flow back to' the boiler as rapidly and uniformly as possible. Return connections should prevent the water from backing out of the boiler. - 5. Automatic boiler feeders and low water cut-off devices, which shut off the source of heat if the water in the boiler fails below a safe level, are recommended for mechanically-fired boil ers. Boiler Troubles A complaint regarding boiler operation generally will be found to be due to one of the following: 1. The boiler faffs to deliver enough heat. The cause of this condition may be: (a) poor draft; (6) poor fuel; (c) inferior attention or firing; (d) boiler too small; (e) improper piping; (/) improper arrangement of sections; (g) heating surfaces cov ered with soot; (A) insufficient radiation installed; or (0 with mechanical firing, fuel-burning equipment too small. 2. The water line is unsteady. The cause of this condition may be: (a) grease and dirt in bailer; (b) water column connected to a very active section and, therefore, not showing actual water level in boiler; or (c) boiler operating at excessive rate of out put. 3. Water disappears from the gage glass. This may be caused by: (a) priming due to grease and dirt in boiler; (b) too great pressure difference between supply and return piping preventing return of condensate; (c) valve closed in return line; (d) con nection of bottom of water column to a very active section or thin waterway; or (e) improper connections between boilers in battery permitting boiler with excess pressure to push return ing condensate into boiler with lower pressure. . 4. Water ts carried over into steam main. This may be caused by: (a) grease and dirt in boiler; (b) insufficient steam dome or too rn>H steam liberating area; (c) outlet connections of too small area; (d) excessive rate of output; (e) water level carried higher than specified. 5. Boiler is slow in response to operation of dampers. This may be due to: (c) poor draft resulting from air leaks into chimney or breeching; (b) inferior fuel; fc) inferior attention; (d) accumulation of clinker on grate; or (e) boiler too small for the load. ' 6. Boiler requires too frequent cleaning of fives. This may be due to: (a) poor draft; (b) smoky combustion; (c) too low a rate of combustion; or (d) too much excess air in firebox caus ing shilling of gases. 7. Boiler smokes through fire door. This may be due to: (a) defective draft in chimney or incorrect setting of dampers; (b) air leaks into boiler or breeching; (c) gas outlet from firebox plugged with fuel; (d) dirty or clogged flues; or (e) improper reduction in breeching size. 8. Low carbon dioxide. This may be due in oil burning boil ers to: (a) improper adjustment of the burner; (b) leakage through the boiler setting; (c) improper fire caused by a fouled nozzle; or (d) to an insufficient quantity of oil being burned. Cleaning Boilers All boilers are provided with flue cleanout openings through which the heating surface can be reached by means of brushes or scrapers. Flues of solid fuel boilers should be cleaned often to keep the surfaces free of soot or ash. Gas boiler flues and burners should be cleaned at least once a year. Oil-burning boiler flues should be examined periodically to determine when cleaning is necessary. The grease used to lubricate the cutting tools during erec tion of new piping systems serves as a carrier for sand and dirt, with the result that a scum of fine particles and grease accumulates on the surface of the water in all new boilers, while heavier particles may settle to the bottom of the boiler and form sludge. These impurities tend to cause foaming, pre venting the generation of steam and causing an unsteady water line. .. This unavoidable accumulation of oil and grease should be removed by blowing off the boiler as follows: If not already provided, install a surface blow connection of at least 114-in. nominal pipe size with outlet extended to within 18 in. of the floor or to sewer, inserting a valve in this line close to boiler. Bring the water line to center of outlet, raise steam pressure, and while fire is burning briskly open valve in blowoff line. When pressure drops, close valve and repeat process adding water at intervals to maintain proper level. As a final opera tion bring the pressure in the boiler to about 10 psi, close blowoff, draw the fire or stop burner, and open drain valve. After boiler has cooled partly, fill and flush out several tiroes before filling it to proper water level for normal service. Where the outlined blowing-off procedure does not remove the grease and dirt and obtain clear boiler water, it may be Heating Boilers, Furnaces, Space Heaters - 509 necesary to use a detergent, type of cleaner in which case the boiler manufacturer as well as cleaner manufacturer should be consulted regarding procedure to be followed.. When addition of water to a system becomes necessary it is advisable to operate the boiler or at least to raise the water temperature to the boiling point in order to permit escape of oxygen and other dissolved gases that would be corrosive if the boiler is out of operation. '' Treatment of Boiler Water Corrosion on the water ride of a boiler can be prevented by proper treatment of the boiler water. Generally, treatment which ,will remove the dissolved oxygen and carbon`dioxide and maintain a minimum pH of 11 (slightly alkaline water) will effectively prevent corrosion. A pH higher than 11 may be used although the boiler water is more likely to foam and cause wet steam with the greater concentration of alkali. A number of compounds are being marketed for this purpose. The Steel Boiler Institute adopted a conditioning compound for use with steel boilers after an extensive cooperative study and many members of the Institute either supply this com pound with their boilers or have it available. It should be emphasized that when the character of the water is such that treatment is required, the treatment should be administered immediately after the boiler and system have been cleaned. It is not good practice to fill a'boiler with fresh water and allow it to stand idle as the dissolved- gases in fresh water available in many localities can start corrosive action in a very short time. After refilling a system it is' ad visable to elevate the temperature close to the boiling point to drive off the dissolved gases immediately. . Care of Idle Heating Boilers - Heating boilers are often seriously damaged during sum mer months due chiefly to corrosion resulting from the com bination of sulfur in the soot with the moisture in the cellar air. At the end of the heating season the following precau tions should be taken: '' 1. All heating surfaces should be cleaned thoroughly of soot, ash, and residue, and the heating surfaces of steel boilers should be given a coating of lubricating oil on the fire side. 2. All machined surfaces should be coated with oil or grease. 3. Connections to the chimney should be cleaned, and in case of small boilers, the pipe should be placed in a dry place after cleaning. 4. If there is much moisture in the boiler room, it is desirable to drain the boiler to prevent atmospheric condensation on the heating surfaces of the boiler when they are below the dew-point, temperature. Due to the hazard that someone may inadverently build a fire in a dry boiler, however,* it is safer to keep the boiler filled with water, particularly in residential installations. Air can be excluded from a steam boiler by raising the water level into the steam outlets. A hot water system usually is left filled to the expansion tank. 5. The grates and ashpit should be cleaned. 6. Clean and repack the gage glam if necessary. 7. Remove any rust or other deposit from exposed surfaces by scraping with a wire brush or sandpaper. After boiler is thor oughly cleaned, apply a coat of preservative paint where re quired to external parts normally painted. - 8. Inspect all accessories of the boiler carefully to see that they are in good working order. In this connection, oil all door hinges, . damper bearings, and regulator parts. 9. If a system has been drained and refilled with fresh water, the boiler should be fired long enough to elevate the water temperature close to the boiling point to drive off dissolved oxygen and carbon dioxide. These gases can be responsible for excessive corrosion if allowed to remain in the system. ' WARM AIR FURNACES Warm air heating furnaces of a cumber of types and a wide range of sizes are listed and illustrated in the Catalog Data Section. Warm air furnaces may be classified in several different ways: . . . . 1. According to method of beat distribution--these are either gravity or mechanical (blower) furnaces. 2. According to fuels for which the furnaces are designed-- these are coal hand-fired or stoker-fired, oil, gas, or wood. 3. According to materials of construction--they are cast iron, .low carbon steel, and occarionally high temperature steel al loys. 4. According to design or. construction, such as drum and radiator, tubular, horizontal, etc. Gravity Warm Air Furnaces A gravity furnace is one in which the motive head pro ducing air flow'depends upon the difference in density be tween the heated air Leaving the top'of the caring and cooled air entering the bottom of the casing. Since this gravity head is relatively low, the furnace must have low internal resist ance to the flow of air, and relatively large areas must be available for free circulation within the furnace caring. It is common practice to provide approximately 50 percent free- air area through gravity-type furnaces. ... - - ' Furnaces for gravity-type systems are available in designs suitable for central heating, pipeless furnace, or unit floor- furnace installations. Booster fans are sometimes used, in conjunction with gravity systems, to increase air circulation. Where a fan is to be used with, a furnace casing sized for gravity air flow, some form of baffling must be employed to restrict the free area within the earing and to force impinge ment of the air against the heating surfaces. Where square casings are used, the corners must be baffled. .' Mechanical Worm Air Furnaces Mechanical or forced warm-air furnaces include fans or blowers as integral parts, for the purpose of circulating the air, and usually include air filters. Centrifugal fans with either backward- or forward-curved . blades are the typo most commonly used. Motors may be mounted on the fan shaft or connected to the fan by a belt drive. Adjustable pulleys are desirable.to provide means of regulating the quantity of air distributed to the heated spaces. Either the motor load or the noise considerations may limit the maximum operating fan speed. Two-speed motors have given successful operating results. Motors and mountings must be carefully selected for quiet operation. Electrical conduit and water piping must not be fastened to, nor make contact with, the fan housing. Filters Several types of filters are available for mechanical warm air furnace applications, and are discussed in Chapter 24. For maximum efficiency and life under operating conditions, fil ters should not be subjected to a temperature in excess of 150 F. Filters should have at least 80 percent average effi ciency on an S-hr test at a maximum resistance of 0.25 in. of water. Filter resistance rises rapidly with the accumula tion of dirt, and may reduce the air circulation over heating surfaces. In domestic furnaces, the maximum velocity, based on nominal filter area, should not exceed 300 fpm. 510 CHAPTER 35 1959 Guide Fuel Utilization - A combustion rateof from 5 to 8 lb of coal per (square loot of grate) (hour) is recommended for residential furnaces. A higher combustion rate is permissible with larger furnaces for buildings other than residences, depending upon the ratio of grate surface to heating surface, firing period, and avail able draft. In residential furnaces for coal burning, the ratio of hating surface to grate area will average about 20 to 1; in commer cial sizes the ratio may be as high as 50 to 1, depending on fuel and draft. Furnaces may be installed singly, each fur nace with its own fan, or in batteries.of a number of furnaces, using one or more fans. * Where oil fuel is used, care .must be exercised in selecting the proper size and type of burner for the particular size and type of furnace used. Furnaces for burning oil fuel are usu ally designed for blow-through installations so that, the pres sure in the air space is higher than that in the combustion chamber or flues. The National Warm Air Heating and Air Conditioning Association has prepared a Tentative Code for Testing and Rating of Oil-Fired Furnaces. Compact fan- fumace-burner units are available, suitable for basement, closet, or attic installations. Gas-fired forced air furnaces should conform in .construc tion and performance to A.GA. Approval Requirements. Heavy Doty Fan Furnaces Fan furnaces for large commercial and industrial building*, churches, schools, etc., are available in ranging from 300,000 to 6,000,000 Btu per (hour) (unit). Heavy duty furnace heaters may be arranged in battery eornhinatiftn* of one or more units. . r Most manufacturers of heavy duty .furnaces rate their furnaces in Btu per hour, and also indicate .the number of square feet of heating surface. Limitations on temperature of flue gases, heat exchanger, and casing as well as carbon monoxide and air temperature rise are *i*n factors in estab lishing ratings for these units. These limits are shown in the ASHAB Code for Testing and Rating Heavy Duty Furnaces and Direct-fired Unit Heaters. " Control of temperature is secured through (1) controlling the quantity of heated air entering the room, (2) using mix ing dampers, or (3) regulating the fuel supply. The design of heavy duty fan furnace heating systems is in many respects similar to-that of the central fan heating sys tems described in Chapter 19. Ducts are designed by the method outlined in Chapter 21. MATERIALS AND CONSTRUCTION Both cast-iron and steel furnaces are made in capacities ranging from those for small insulated residence application with inputs of 40,000 Btu per hour or less, to capacities as large as 600,000 Btu per hour. Cast-iron furnaces are usually constructed with a mini mum sectional thickness of V* in., and effectively resist high temperatures and corrosion. They usually have a fairly large heat capacity because of their m*** which provides a dis tinct fly wheel or carry-over hating effect. ' In steel furnaces welding, riveting, or both are used to join the formed metal. The use of steel casting*, however, is rare, because of the cost, and because high stresses are not en countered in normal furnace construction. Steel furnaces have low heat capacities as a result of their relatively low mass and, therefore, deliver heat rapidly on demand. FURNACE RATING . Rating Equations for Gravity Warm Air Furnaces* Until a .method of testing and rating gravity warm air furnaces has been developed, the following empirical rating equations are recommended by the National Warm Air Heat ing and Air Conditioning Association. . Gravity warm air furnaces of conventional design, having ratios (of heating surface to grate ares) of 15 to 1 or greater, and having a ratio of eating area to face area not less than 0.4, are rated by the following equations: 1. Hand-fired furnaces converted to Stoker, Gas, or Oil Firing. Bonnet Capacity in Btu per hour = 1785 X 8 X 1233 (2) 2. Hand-fixed furnaces, with ratios of heating surface to grate area greater than IS to 1 and less than tS to 1. Bonnet Capacity in Btu per hour -- 1785 XSX 1333 (3) \3. Hand-fixed furnaces with ratios of heating surface to'grate area m excess of tS to 1. . . ' Bonnet Capacity in Btu per hour = 1785 X 25 X G X 1333 (4) where S * heating surface, in square feet. G actual grate area, in square feet. ' , The Register Delivery Rating is equal to 0.75 x (Bonnet Capacity) .The Leader Pipe Rating in square inches, formerly used as a rating unit, may be found by dividing the Register Delivery Rating by 136. . ` Heating Surface of Furnace Prime heating surface is defined* as surface above the top of the grate having hot gases or live fuel on.one side and cir culating air over the other, and in all-cases is measured on the exterior or air side. The areas of the outer casing, tie inner liner, and any radiation shields shall not be considered as heating surface.' In determining the amount of heating surface, extended surfaces are considered to be prime heating surface subject to the following limitations: ' ' 1- Extended heating surface may consist of fin* ribs, webs, lugs, or other projections from the prime heating surface. Pro- jections lea than Vi in. thick at the base, and extending more than 1 in. from the prime surface are classified as fin* 2. Integral fins are continuously welded to, or cast as a part of, the prime heating surface. Both sides are included as heat ing surface, subject to the following allowances: - Distance from prime 1st in. 2nd in. 3rd' in. Over' 3 in. Ratio of effective area 0.40 0.30 0.20 None 3. Non-integral fins are spot welded to, or otherwise held in Ime contact with, the prime beating surface. Both sides are ineluded as heating surface, subject to the following allowances: Distance from prime 1st in. 2nd in. 3rd in. Ratio of effective area 0.30 0.20 0.15 Heating Boilers, Furnaces, Space Heaters - 511 4 In the case of ribs, webs, or lugs more than V* in. thick at the base and extending less than 1 in. from the prime surface, the entire surface in contact with circulating air is included as fay>tmg surface. 5 In the case of riba, webs, or lugs more than M in. thick at the base and extending more than 1 in. from the prime heating surface the areas of both sides of the first inch are included as prime surface. The portions projecting beyond 1 m. are treated as integral fins. Grate Area ' Grate area is defined* and treated for purpose of rating as follows: . " 1 The nointrial grate area is defined as the total cross-sec tional area of the bottom of the firepot. In steel furnaces the nftminul grate area is the cross-sectional area inside the fire brick lining. . ' 2. The actual grate area, used for calculating the ratios of hating surface to grate area, is the nominal grate area minus . certain areas that cannot be considered as part of the grate itself. The following rules govern these deductions: (1) If a solid, con tinuous ledge extends around the grate and inside the firepot, any area of this ledge extending inside of a circle, the diameter of which is 1 in. less than-the diameter of the bottom of the firepot, *h*U be deducted. (2) If separate, solid projections ex tend from the firepot towards the grate, the areas of any por tions of these projections extending inside of a circle, the diam eter of which is 3 in. less than the diameter of the bottom of the firepot, be deducted. (3) In the case of grates which are inclined, or are conical, the projected area is the same as the nominal grate area. The latter should, therefore, be used after pinking any necessary deductions. Ratings for Forced Air Furnaces For solid-fuel-buming, forced air furnaces having bonnet capacities between 80,000 and 250,000 Btu per hour, no standard method of test has been accepted, although eventu ally such codes will be developed. The National Warm Air Treating and Air Conditioning Association recommends the following empirical equations for use in rating solid fuel forced air furnaces: 1. Hand-fired furnaces converted to Stoker, Gas, or Oil Firing. Bonnet Capacity in Btu per hour -- 2265 X S X 1.177 (5) 2. Hand-fired furnaces, with ratios of heating surface to grate area greater than IS to 1 and less than tS to 1. Bonnet Capacity in Btu per hour -- 2265 X 5 X 1.177 (6) 3. Hand-fired furnaces with ratios of heating surface to grate area in excess of tS to 1. Bonnet Capacity in Btu per hour -- 2265 X 25 X G X 1.177 (7) where . S -- heating surface, in square feet. G -- actual grate area, in square feet. The Register Delivery Rating is equal to 0.85 X (Bonnet Capacity). The following testing and rating codes have been generally accepted in the industry: Commercial Standard CS-109-44 for rating solid-fuel-buming, forced air furnaces having bonnet outputs of 80,000 Btu per hour or less. This provides a method of rating small coal-fired forced air furnaces by test. A Tentative Code for Testing Oil-Fired Furnaces. This code has been adopted by the National Warm Air Heating and Air Conditioning Association for rating oil-fired furnaces by test. The American Gas Association method of rating gas-fired furnaces on performance under tests. This is described in the Approval Requirements for Central Heating Gas Appliances --Vol. H, Gravity and Forced Air Central Furnaces, Z21.132. Commercial Standard 113-51 is a method of rating oa-buming floor furnaces by test. __ . ,, Commercial Standard CS 104-49 is a method of rating warm air furnaces equipped with pot-type off burners by test. Various codes covering the construction and. performance of appliances as related to fire hazards have been developed by Underwriter Laboratories, Inc. In addition, there are many municipal codes* which regulate construction and installation of furnace equipment. The yardstick of the National Warm Air Heating and Air Conditioning Association provides criteria for evaluating a furnace Auriga and installation against industry accepted stand ards. FURNACE EFFICIENCY Rating formulas of the National Warm Air Heating and Air Conditioning Association are based on 55 percent effi ciency for gravity coal furnaces and 65 percent efficiency for forced air coal furnaces. In the tentative Oil Testing Code the contemplated minimum efficiency is 70 percent for oilfired forced air furnaces. Gravity gas furnaces approved by the American Gas Association are assigned a rating based on 75 percent efficiency. All forced-dr gas-fired furnaces ap proved by American Gas Association are assigned a rating based on 80 percent efficiency. . DESIGN CONSIDERATIONS ' Considerations of prime importance in the design of warm air furnaces and some general suggestions to be observed in connection with each, are as follows: . 1. Adequate heat transfer surface. a. Heat transfer rates of 2000 to 4500 Btu per (hour) (square foot) of heating surface may be obtained with out unduly high metal temperatures. With some types of design somewhat higher rates are acceptable. b. Fins, pins, and bosses are frequently used to add surface and to break down superficial gas films, both on gaa-to- metal and met&l-to-air surfaces. c. Surface and stack (flue gas) temperatures are good in dications of the amount and effectiveness of the beating surfaces. 2. Safe and efficient combustion of fuel. a. Proper mixture of fuel and air is necessary for efficient combustion. This necessitates careful attention to the Aorign of grates, nozzles, burners, air inlet areas and lo cation, ana combustion chamber baffling. t b. Regulation of the quantity and the distribution of the air for combustion should be provided by use of check dampers, draft regulators, draft hoods, air shutters, and air orifices. c. Total draft loss through appliances should not exceed that available from chunneyB which would normally be obtainable in the size of building which the appliance will supply with heat. d. The use of ignition safety devices such as safety pilots, hold-fire controls, and the like is recommended. 3. Fuel capacity of appliance. a. With solid fuels adequate coal capacity should be pro vided for at least 5 hr of operation at the maximum rated combustion rate. 4. Adequate circulation of air over heating surface. a. In gravity furnaces, free air space between casing and heat exchanger should be great enough to permit free flow over all surfaces. b. Forced air furnace design must include fans having ' . proper capacity and suitable performance characteris tics. Internal static pressures must be minimized without losing the advantages of high-velocity circulation over the heat exchanger surfaces. c. The air flow over the heating surface must be directed to obtain maximum efficiency and to eliminate hot spots and air noises. ' 512 . CHAPTER 35 1959 Guide d. Air velocities at bonnet should cot be much in excess of 1000 fpm, and air temperature distribution at the furnace outlet should be uniform within approximately :fc 30 deg. 5. Durability. . a. A minimum metal weight for gas-fired heat exchangers is established as No. 20 VS. Gage for plain carbon steel by the A.GA. Approval Requirement* for Central Heat ing Gas Appliances, with some municipal codes specify ing IS gage. Cast-iron sectional thicknesses of Vt in. to in. ore recommended. b. Added strength and reinforced designs may be required to preclude damage in shipment, burning out from over firing, or corrosion from condensation. - e. Maximum heat exchanger surface temperatures which may be used vary with the metal. The American Gas Association Approval Requirements for Central Heat ing Gas Appliances specify a maximum of 875 F for cast- iron or steel gas furnaces, and the National Bureau of Standards C$ 109-44 Code for Forced Air Solid Fuei- Bummg Furnaces specifies 1000 F as a maximum surface temperature. These temperatures define the range in which oxidation of non-alloy ferrous metal begins. The use of proper alloy additions increases the temperature resistance properties of metals. d. Casing temperatures should be controlled so that they do not become hazards by burning those who touch them, or by creating fires. 6. Serviceability. a. Those parts of the furnace which may be subject to soot, fly-ash, or condensation deposits should be accessi ble for cleaning. b. Parts which may require adjustments or replacements, such as grates, baffles, liners, controls, should be remov able. c. Furnaces should be so designed that they can be ingt-nllerf with a'minimum of difficulty. 7. Control. a. Thermostatic controls of various types should be to correlate space temperatures with unit operation. b. Controls should be provided wherever posable; to pre vent the occurrence of excessive temperatures or other conditions which might cause unsafe operation in any ' part of the unit. 8. General design considerations. ' a. Furnace casings are normally constructed of formed and - painted sheet steel or of galvanized iron. The rawing should be protection from excessive radiation lossesand . temperatures by use of insulation or sheet steel air space liners. Liners should extend from the grate level to the . top of the furnace and should be spaced from 1 in. to IV? in. from the outer rawing b. The hood or bonnet of the casing above the furnace should be as high as basement conditions will allow, to form a plenum chamber over the top of the furnace. The tends to equalise the pressure and temperature of the air leaving the bonnet through the various openings. It is generally considered advisable to off the warm ' air pipes from the side of the bonnet near tbe top, as this method of take-off allows the use of a higher bonnet and thus provides a larger plenum chamber. c. Warm air outlet and return air connections should be designed so that the ductwork may be easily attached. A % in. flange is normally used for this purpose. d. Suitable provision should be made in appliances so that the controls and humidifiers may be installed in the proper location. When these auxiliary units are installed in the ductwork, detailed instructions should be pro vided to insure their proper location. e. The flue connection should be of integral flue pipe size, - and provision should be made to attach the flue pipe to the flue outlet of the furnace. - HUMIDIFICATION EQUIPMENT Evaporating pans are usually located in the outlet air. There is a present trend toward heating the water. Equip ment for doing this may make use oi sprays, or it may take the form of water circulating coils placed within the com . bustion chamber, and connected by pipes to the humidifier pans where a constant water level is maintained by some separate Boat device. All humidifiers require provision for removal of dirt and lime. SPACE HEATERS Space heaters may be classified in several ways, such as: 1. By the type of fuel used as coal, wood, gas, and fuel oil. 2. According to the method of heat distribution as circulators or radiant types. A radiant heater is one in which the heat ex changer surface is exposed directly to the room atmosphere, and the generated heat is dissipated primarily by radiation. A circu lating heater is essentially a jacketed radiant heater from which circulation of room air is promoted by the chimney effect caused by the movement of air passing upward between the jacket and heat exchanger surface. 3. According to method of design for particular fuel types, such as: (a) surface-fired and magazine-feed for solid fuels, (b) vaporizing pot-type and blue-flame heater for oil, and (c) vented and unyented heaters for gas. (The type of gas burner design, such as injection, yellow flame, power, and pressure, may also be mentioned.) SOLID FUEL-FIRED HEATERS Surface-fired heaters normally have a front firing door and are operated with relatively shallow fuel beds. A maga zine-feed heater includes a deep reservoir of fuel to lengthen tbe attention intervals. In a true magazine-feed beater the rate of fuel ignition would be equal to the rate of burning; and self-feeding should operate to move the unbumed fuel by gravity flow from the magazine section into the hearth area. However, the ideal balance between rate of ignition and rate of burning is virtually impossible to attain for any solid fuel under normal usage, although self-feeding may be obtained with wood and some free burning coals. Thus, a magazinetype space heater is essentially a deep surface-fired heater, its principal difference from other heaters being increased fuel capacity. ' Materials and Construction There is no accepted code governing the construction of solid-fuel-buming space heaters. In past years cast iron was used predominantly in the construction of coal and wood heaters, with the exception of the so-called airtight heaters designed as low-cost wood-burning units with little considera tion for long life, and stoves were priced on a poundage basis. The present trend is toward fabricated steel parts and welded assemblies, although cast iron is still used for grates, firebox liners, and parts subject to high temperatures. Refractory firebox liners are also used quite extensively. Formed sheet steel is used predominantly for the outer jacket of circulator heaters, although heaters with outer cas ings formed from cast iron are still readily available. Circu lator cabinets normally have surfaces finished with a porce lain enamel, while the casing of a radiant heater is finished with an air-dried japan or a baked enamel. Both welding and stove bolts are used in unit assembly, and stove cement is used on section joints to prevent air leakage. This latter is extremely important to obtain a low rate of combustion when desired. Testing and Rating . There is no accepted code governing tbe method of testing and rating solid fuel space beaters. A tentative procedure, Heoting Boilers, Furnaces, Space Heaters 513 T5 3443 ha been by the Division of Trade Standards, National Bureau of Standards, but is based on use of an thracite as a rating fuel, although bituminous coals are used predominantly as heating fuels. This procedure, which has been the basis of published ratings, consists of determining the heater output, expressed in Btu per hour, by the indirect method. The measurable heat losses: (1) loss due to moisture in the fuel, (2) loss due to heat in the dry flue gases, (3) loss due to unbumed carbon monoxide, and (4) loss due to un bumed combustible in the ash and refuse, are measured by test. The total of these four measurable loses, plus an as sumed value for unaccounted for losses, are then subtracted from the heat input. The difference multiplied by the burning rate in pounds per hour is the heater output. When Rising anthracite as the rating fuel, the unaccounted for loss has been assumed to be zero. It has been accepted practice to use a 20 percent allowance for the unaccounted for losses when burning a bituminous coal. The value of this factor has been under study and, although test work is in complete, a value of 12 percent of the heat input has been determined as representing the losses due to smoke and un bumed hydrocarbons for a surface-fired heater, when burn ing a high volatile bituminous coal. No allowance is made for a radiation loss, as this is useful heat. Design Considerations Some important considerations in the design of solid-fuel space heaters are: . 1. Suitable protection by baffling or insulation against over heating of floors and walls. Although there are..no industryaccepted standards by which floor and wall temperatures may be determined, some indication of heater performance, with re gard to overheating, may be found by the use of the comer Booth test arrangement described in National Bureau of Stand ards Commercial Standard CS 103-43 and t/ndencriters Lab oratories Standard, Subject 896, mentioned in following section on Oil Heaters. 2. Tight heater construction to prevent air leakage, and to enable maintenance of a suitably low minimum burning rate. This includes a ground, paper tight joint between the ashpit door and door frame. 3. Sufficient free air space, between the casing and heat ex changer of circulating beaters, to permit free air flow over all surfaces maintain a suitably low casing temperature. 4. Protection of all metal parte from deterioration due to high temperature. This may be accomplished by: (a) fabrication of certain parts from cast iron or an alloy iron, (b) protection by a refractory liner, (c) use of high temperature enamel coat ings, (d) directing air against hot spots. 5. Proper admission of secondary air to complete the combus tion process. Care should be taken to prevent this air from also functioning as primary air. 6. Strength in assembly to prevent transportation and use damage. Considerable work has been directed toward improvement of the performance of bituminous coal-fired space heaters, with particular reference to smokeless operation under con ditions of normal operation such as obtained in homes. A smokeless coal heater has been developed by Bituminous Coal Research, Inc., wherein smokeless combustion is ob tained by admitting secondary air through a narrow slot, extending from tide to tide, above the edge of the fuel bed where the gas leaves to enter a vertical gas passage* Com plete miring of the volatile material, released from the coal in the magazine, with the secondary air supplied is obtained as both streams pas under the bottom of the arch. Com plete combustion results from this intimate muring in a re gion which maintniiifl itself at high temperatures even during hanking periods. OIL HEATERS Vaporizing pot-type oil heaters consist of: (1) a metal pot in the bottom of which the oil is vaporized, the vapors burn ing at or near the top of the pot and (2) a secondary com bustion chamber, or heat exchanger, in which combustion is completed. The flue connection is made to this chamber or through a second heat exchanger which may be of tbe diving- flue type installed to increase efficiency. The burner may be designed for operation both with and without mechanical draft. . Blue-flame oil burners differ from tbe pot-type variety in that removable perforated sleeves are provided above an oil pan instead of a metal pot, and lighting rings or kindlers are used for easy Lighting. Both types of oil burners operate by the burning of the oil vapor rather than the oil itself, the oil being first fed to a chamber in which the oil is entirely vaporized, then mixed with air introduced through suitably located ports and burn ing at'the top of the pot or perforated sleeves. Such heaters are designed to burn No. 1 oil' (See Table 4, Chapter 33) or kerosine (coal oil). At no time should oil heavier than that for which the burner is designed be used, 'as heavier oils may cause excessive carbonization in the burner or fuel feed line. Materials and Construction Formed sheet steel and welded assemblies are used pri marily in oil heater construction. Standards governing con struction which have been generally accepted are: 1. Commercial Standard for Flue-Connected OH-Buming Space Heaters Equipped rpith -Vaporizing Pot-Type Burners, CS101-43 (National Bureau of Standards). 2. Standard for Oil-burning Stoves, Subject 896 (Under . writers' Laboratories, Inc.). 3. Standard for Construction and Performance of Oil Burn ers for Installation tn Stoves and Ranges, Subject 865 (Cinder- writers' Laboratories, Inc.). Some states or municipalities have codes which apply lo cally, but usually apply primarily to installation, and the Underwriters' Laboratories label of approval is sufficient to cover acceptance of the unit. Testing and Rating Commercial Standard CS101-43 is intended to provide a uniform standard method for ascertaining the maximum practical heat output in Btu per hour of flue-connected oil burning space heaters under approximately normal service conditions. This method is based upon the following, equations: ' Hr A - B (8) and E m Hr/A . tohere A total beat of fuel used. ' B - heat lost in flue gases. Hr = net beat delivered to the room. E " unit efficiency. (9) i 514 CHAPTER 35 1959 Guide The following minimum performance requirements are stipulated: . 1. Adequate provision for of lighting nH insurance against loss of ignition prior to heating of burner. 2. Ease of operation of controls. 3. Proper operation of burner without excessive carbonisa tion with grades of oil recommended by the manufacturer. 4. The heater shall be capable of passing the 6 percent ICHAM smoke test. 5. The heater shall be capable of operating with an overall efficiency of not less than 70 percent under conditions of test, or at a lower stack draft recommended by the manufacturer. Design Considerations Some factors important in the design of oil-burning heaters 1. Proper pitch of oil lines from the sump to the burner, thus preventing vapor and air lock. - 2. Proper positioning of the oil sump or constant-level valve to maintain the proper oil level in the burners, if factory as sembled. . 3. Tight construction, not only of oil Hum, but of oil sump, and burner to prevent a hazardous condition due to oil leakage. 4. Provision for leveling and aligning the entire for maintenance of proper operation. If a separate fuel *nir is used, the heater should have provision for secure fanning to the floor to prevent excessive strain oq oil supply linoj qnd the consequent danger of leakage of oil. - 5. Provision of a draft regulator to prevent abnormal draft fluctuations. 6. Proper shielding of an attached fuel oil supply t-nfc to prevent excessive oil temperatures. 7. All metal parts subjected to'the corrosive action of the oil shall be made of noncorrodible metal, or of metal suitably coated to resist corrosion. 8. The heater should have suitable baffling or insulation to prevent overheating of floors and walls. '. 9. Strength in assembly to prevent transportation nd damage. ; - GAS HEATERS _ Vented gas heaters are defined as those capable of remov ing 90 percent of the flue gases through a angle flue outlet. All heaters having a gas input rating in excess of 50,000 Btu per hour must be of the vented type in order to'meet ASA Approval Requirement* for Gar-Fired Room Heaters* Space heaters may be classified by burner type as follows: 1. Injection Burner type which employs the energy of a jet of gas to inject air for combustion into the burner and mix it with the g*- . 2. Yellow Flame Burner type in which secondary air only is depended on for the combustion of the g* Materials and Construction Standards covering materials and accessories used in the construction of gas heaters are described in ASA Approval Requirements for Gas-Fired Room Heaters* and in applica ble lasting Requirements* Efficiency Requirement Vented space heaters having input ratings in excess of 20,000 Btu per hour are required to have a heating efficiency of not less than 70 percent,* Based on the total hating value of the gas. Vented space heaters having input ratingB of 20,000 Btu per hour or less are required to have a hating efficiency of not less than 65 percent.* These efficiencies are based upon the following equation: . . c, - 100 - -- X 100 .9 (10) ithere Ct " heating efficiency, percent. Hf = heat above room temperature carried away by the flue products, Btu per hour. q = hourly gas heat input, Btu per hour. Radiant heaters are required to have a radiant efficiency of not less than 28 percent. Design Considerations Some factors important in the design of gas heaters are: 1. Proper design of the burner head, port and locations so that tile flame will not lift, float, or flash back, and be'ex cessively noisy in operation. ' 2. Proper venting of combustion chamber for relief of forces resulting from ignition of an explosive mixture of gan and air. 3. Protection of valve handles to prevent excessive tempera ture rise during operation. ' 4. Insulation and baffling of heater to prevent overheating of walls and floor. INSTALLATION OF SPACE HEATERS The two most important considerations involved in the installation of a space heater are safety and chimney draft. The items of chimney details and flue connections which should have special attention are outlined in Chapter 36, Chimneys and Draft Calculations. In all cases, it is recom mended that installation be made in accordance with the current National Braiding Code. . REFERENCES _ * I -- B -- R Testing and Rating Code for Low Pressure Heat ing Boilers (Institute of Boiler and Radiator Manufacturers, July 1952). * Testing and rating code for boiler-burner units (Engineering Standards Part II, Mechanical Contractors Association of Amer ica, 1856). ` *1 ~ B ~ R Ratings for Cast-Iron Boilers (Institute of Boiler and Radiator Manufacturers, May 10, 1955). - 4 Net load recommendations for heating boilers (Engineering Standards Part II, Mechanical Contractors Association of Amer ica, 1956). * Comfort Heating (American Gas Association, 1938, p. 35). 'Gravity Code and Manual for the Design and Installation of Gravity Warm Air Heating Systems (National Warm Air Heating and Air Conditioning Association, Mann| No 5, 5th ed.). .' 'Recommended forms for municipal ingt.nti.m fire codes are included in Code and Manual for Design and Installa tion of Warm Air Winter Air Conditioning Systems (National Warm Air Heating and Air Conditioning Association, Manual 7, 4th ed.). ' * B. A. Landry and R. A. Sherman*. Development of a design of smokeless stove for bituminous coal (ASME Annual Meet- American oumaara Approval Requirements for Gas-Fired Room Heaters (American Standards Association, Z21 J1.1954). *American Standard Listing Requirements for: Automatic Mots (Z2IJ20, 1951); Gas Appliance Thermostats (Z2123, ilciv' Gas Appliance Pressure Regulators (Z21.1S, 1956); Automatic Valves for Gas Appliances (Z2121, 1952); (American Standards Association). CHAPTER 36 CHIMNEYS AND DRAFT CALCULATIONS Draft Definitions, Theoretical Natural Draft, Factors Affecting Natural Draft, Available Draft, Required Draft} Industrial Chimneys, Available Draft for the Industrial Chimney, Determining Industrial Chimney Sizes} Residential Chimneys, Available Draft for Residential Chimneys, Short Chimneys, Determining Residential Chimney Sizes, Draft Require ments of Apptiances, Chimneys for Gas Appliances; Recommendations of the National Board of Fire Under- writers, General Considerations ` RAFT is the pressure difference associated with the FACTORS AFFECTING NATURAL DRAFT D -movement of flue gases through a flue or chimney. As indicated in both Equations 1 and 2, the theoretical Natural draft is caused and measured by tire difference isnatural draft is directly proportional to the height of the flue weight of a column.of flue gas within the flue and a corre and is dependent upon the absolute mean temperature of the sponding column of air of equal dimension outside the flue. gases within the flue. It is also directly proportional to the Natural draft is always negative and is expressed in inches of . density of the air outside the flue although the effect of this water gage. factor is minor. When the movement of air is supplied by a fan, the draft is The formulas for theoretical natural draft are based on said to be forced or induced. When the fan is located so as to rr^nn or average temperature which is one half of the sum push the flue gases through the flue, the draft is forced. When of the entering and exit temperature. Since the difference in the fan is located so as to draw the flue gases through the exit and entering temperatures, or the temperature gradient flue, the draft is induced. ___ in the flue, is due to the escape of heat through the walls of THEORETICAL NATURAL DRAFT Theoretical natural draft is produced solely by the differ the flue and chimney, the heat transfer characteristics of the chimney construction affect draft. Heat transfer is also af fected by the rate of flow of the flue gases through the flue ence in weight of the column of flue gases within the flue and that of a corresponding column of air of equal dimensions so that draft is also affected directly. The flow of flue gas** through the flue is retarded by fric outside the flue. In the determination of theoretical natural tion which varies directly with the friction coefficient of the draft, no allowance is made for friction or other positive or flue surface, and with the rate of flue-gas flow. The friction negative effects. Theoretical natural draft is expressed by the loss may be estimated by means of one of the formulas for following formula: ducts such as the Fanning equation or it may be estimated with sufficient accuracy by the method used for air ducts. CD (See Chapter 21.) The height of the flue is measured from the point of en where ' D, -- theoretical draft, inches of water. trance of the flue gases to the top of the flue. With no wind to produce an aspirating effect and with no obstruction such as a rain cap at the top of the flue, the column of flue gases H -- height of flue or chimney, feet. B, -- barometric pressure, inches of mercury. p, = density of air at 0 F and 1 atmosphere pressure, pounds may extend upward above the top of the flue for several feet. The effect of this column may be sufficient to overcome the negative or retarding effect of friction and to cause the per cubic foot. ' p. *> density of flue-gas at 0 F and 1 atmosphere pressure, observed draft to exceed the theoretical draft. This added effect has been measured in some test work. A wind blowing pounds per cubic foot. T, = temperature of air surrounding the chimney, Fahren across the top of tbe flue may also produce an aspirating effect sufficient to overcome the effect of friction and to cause the heit absolute. ' T, a temperature of the gases, average or effective, in the chimney, Fahrenheit absolute. observed draft to exceed tbe theoretical. Both of these effects are transient and unreliable and should not be considered in determining the proper design of a chimney. Theoretical natural draft may also be expressed by the following simplified formula in which it is assumed that the densities of the flue gas and of the air are equal at the same temperature and pressure: where p = mean density of atmospheric air, pounds per cubio foot. AVAILABLE DRAFT The available draft produced by any chimney is equal to the theoretical natural draft minus tbe friction loss. Given the height, the heat transfer characteristics of the chimney construction, the entering temperature of the flue gases and their volume, and the friction coefficient of the flue and its dimensions, the available draft is readily calculable. The efficiency of a chimney is defined as the ratio of the observed draft or available draft, produced by tbe chimney 515 . 516 CHAPTER 36 1959 Guide for a given inlet temperature and flow rate, to the ideal draft that would be observed if the same quantity of flue gases traversed the chimney without cooling and without friction. The chimney efficiency may be calculated as follows: . ______________final measured draft 07 ideal draft calculated from the inlet temperature REQUIRED DRAFT Before the proper chimney for a particular installation can be selected or designed, the required draft of the combustion unit must be known. The required draft is equal to the sum of ail of the resistances to gas flow from the point at which combustion air enters the unit to and including the chimney connection. This is based on the assumption that air for combustion is available without restriction (such as would be caused by tightly enclosed building construction) at that dustrial chimney class, and their requirements should be treated accordingly. The majority of industrial chimneys op erate under induced or forced draft, resorting to natural draft operation only in the case of emergencies. They are built of brick, concrete, or steel, depending upon economy and the type of installation needed. Proper height is of importance because of removal of waste products, inasmuch as the prod ucts of combustion are often deflected downward around the chimney and, with the large amount of gases that are ex hausted to the atmosphere through the industrial chimney, downwash can be very objectionable.1 AVAILABLE DRAFT FOR THE INDUSTRIAL CHfMNEY The available draft, Da, for large chimneys and stacks has been estimated with apparent satisfaction in the past by means of formulas which in effect deduct an estimated fric tion loss from a theoretical draft determined as in Equation 1. The friction loss can be estimated by means of one of the formulas available for ducts, such as the Fanning equation. This procedure results in formulas for the available draft as follows: For a cylindrical stack: D, 296M*(e-t.) o.ooi28tyrjL d*BPe (3) and for a rectangular stack: D, VT. _ ^0fXB86WTefUt + y) Tt) (xy)*B*pe (4) point of entrance to the unit. Particularly in residences, un restricted supply of combustion air must be assured. fig. 1 presents information on the fuel-bed draft loss for various kinds of coal burned at different rates. Rough gen eralizations can be given for the losses in the flue passages of boiler or furnace but, on account of the great differences in such devices,- more reliable data on their flue-gas volume, temperature, and flue resistance should be obtained for de sign purposes from their respective manufacturers. Flue gases encounter resistance to flow in breechings or - smoke pipes, and this can probably be treated with sufficient accuracy by means of the method used for air ducts. (See Chapter 21.) The friction in straight ducts can be estimated by means of the last term of Equations 3 and 4. Also, the temperature of flue gases falls during passage through breechings or flue pipes. For uninsulated surfaces this probably can be adequately estimated by assuming a loss of heat from the flue gas of 3 Btu per (hr) (sq ft) (Fahr enheit deg temperature difference between the gases and surrounding air). INDUSTRIAL CHIMNEYS . Chimneys can be classified as residential and industrial, the chief difference being their sizes and the types of draft. Chim neys over approximately lYz ft in diameter are in the in where D. available draft, inches water gage, H = height of chimney above inlet, feet, B. - existing barometric pressure, inches of mercury, p# =* density of air at 0 F, 1 atmosphere pressure, p " density of flue gas at 0 F, 1 atmosphere pressure, T, - temperature of atmosphere, Fahrenheit, abso lute. ' T - temperature of flue gas, Fahrenheit, absolute, W = flue gas flow rate, pounds per second, / = coefficient of friction. L - length of friction duct (approximately equal to H), feet. ' d - minimum diameter of round chimney, feet, 2 and y " length and width of cross-section of rectangular chimney, feet. - The following notes facilitate the use of Equations 3 and 4. 1. The barometric pressure, represented by B,, is the actual pressure at the site of the chimney and not the pressure reduced to sea level datum. In general, the barometric pressure decreases approximately 0.1 in. Hg per 100 ft increase in elevation. - 2. The vnilweight of a cubic foot of chimney gases at OF and sea level barometric preanire is given by the equation: p. 0.131CO* + 0.0950* + 0.083#j (5) In this equation CO, 0, and Nt represent the percentages of the parts by volume of the carbon dioxide, oxygen, and nitrogen content, respectively, of the gas analysis. For ordinary operating conditions, the value of p may be assumed at 009. The effect on the chimney gas density, of superheated water vapor resulting from moisture and hydrogen in the fuel, or of any air infiltration in the chimney proper, is disregarded. Al though water vapor content is not disclosed by Orsat analysis. Chimneys and Draft Calculations 517 its presence tends to reduce Uie setuni weight per cubic foot of chimney gases. 3. The atmospheric temperature is the actual observed tem perature of the outdoor air at the time the analysis of the op erating chimney is made. The mean atmospheric temperature in the temperate sone is approximately 62 F. 4 The chimney gas temperature decreases from the breeching connection to the top of the stack. This drop in temperature depends upon the material and construction of the stack, its or freedom from leaks, its area, its height, and the velocity of the pv*** through it. The same chimney will suffer different temperature losses depending upon the capacity under which it is working, and the variable atmospheric conditions. No fsneral equation covering all these variables has been suggested, ut from observations on chimneys varying in diameter from 3 to 16 ft, and in height from 100 to 250 ft, Equation 6 was de duced :* Kir-*] (6) Tt = temperature at the center of the connection from the breeching, Fahrenheit, absolute! = height of the stack above center liue connection to breeching,feet. 5. The coefficient of friction between the chimney gases and a sooted surface has been taken by many workers in this field as a constant value of 0D16 for the conditions involved. This value, of course, would be less for a new unlined steel stack than for a brick or brick-lined chimney, but in time the inside surface of all chimneys, regardless of the materials of construc tion, becomes covered with a layer of soot, and thus the co efficient of friction has been taken the same for all types of chimneys and generally constant for all conditiona.of operation. For reasons of simplicity and convenience to the render, this constant value of 0JQ16 has been employed in the development of the various special equations and charts shown in this chap ter. ' In important large chimney design, especially when the con struction or the materials are unusual, it is recommended -that use be made of the Reynolds cumber* in determining the fric tion factor, /. ' The following problem illustrates the use of Equation 3: Example 1: Determine the available draft of & natural draft chimney 200 ft in height and 10 ft in diameter, operating under the following conditions: atmospheric temperature, 62F; chim ney gas temperature, 500 F; sea level atmospheric pressure, B, = 2992 in. Hg; atmospheric and chimney gas density, 00863 anH 0.09, respectively; coefficients^ friction, 0016; length of friction duct, 200 ft. The chimney discharges 100 lb of gases per second. Solution; Substituting these values in Equation 3 and reducing, _ Z>. 2.98 X 200 X 29.92 x(/0--.0863 -05.5059)\ Fig. 2....Typical Set of Operating Characteristics of a . Natural-Draft Chimney zero capacity is called shut-off draft, or point of impending delivery, and corresponds to the point of shut-off head of a centrifugal pump. The point of zero draft and maximum capacity is called the wide open point, and corresponds to tiie wide open point of a centrifugal pump. A set of operat ing characteristics may be developed for any size chimney operating under any set of conditions by substituting the proper values in Equation 3, and then plotting the results in the manner shown in Fig. 2. Fig. 3 is a typical chimney performance chart giving the available draft for various gas flow rates and sizes of chim ney. This chart is based on an atmospheric temperature of 62 F, a chimney gas temperature of 500 F, a unit chimney gas 000126 X 100* X 960 X 0.016 X 200 10* X 29.92 X 0.09 - 1.27 - 0.14 = 1.13 in. Fig. 2 shows the variation in the avail&ble draft of a typical 200 ft by 10 ft chimney operating under the general condi tions noted in Example 1. When the chimney is under static conditions and no gases are flowing, the available draft is equal to 1.27 in. of water, the theoretical intensity. As the amount of gases flowing increases, the available draft de creases until it becomes zero at a gas flow of 297 lb per sec ond, at which point the draft loss, due to friction, is equal to tiie theoretical intensity. The point of maximum draft and To solve a typical example: Proceed horizontally from a Weight Flow Rate point to intersection with diameter tine; from this intersection follow vertically to chimney height line; from this intersection follow horizontally to the right to Avail able Draft scale. Starting from a point of Available Draft, take steps in reverse order. . Fig. 3 .... Chimney Performance Chart 518 CHAPTER 36 weight of 0.09 lb per cu ft, sea level atmospheric pressure, a coefficient of friction of 0.016, and a friction duct length equal to the height of the chimney above the grate level. These curves may be used for general operating conditions. For specific conditions, a new chart may be prepared from Equation 4. - DETERMINING INDUSTRIAL CHIMNEY SIZES If the required performance for a proposed chimney is known, and if a chimney-gag velocity is assumed. Equation 3 can be transposed to yield the necessary height, and an equation can be developed for the required diameter. These operations result in the following equations: h--------------;-----------^---------------------- 2.96B, - l'l ~ \T. Tj T4 (7) W The weight of gas per second, W = 12.075 (dV9pc/7'(.) 1959 .Guide where H TM required height of chimney above inlet, feet. d " required minimum diameter of chimney, feet. V *= chimney gas velocity, feet per second. Dr * total required draft, inches of water. ' For large chimneys, it is usual to assume that total con struction cost is least when the product Hd (height X diam eter) is minimum. On this assumption, the product of Equa tions 7 and 8 can be differentiated, and the differential set equal to zero to find the minimum Solution for velocity then yields the following equation: where V* " economical chimney gas velocity, feet per second. Equations 7, 8, and 9 can of course be simplified if values are assumed for some of the factors in it. Some typical values for boiler plants are: Average chimney gas temperature 600 F........................................................ T, -- 960 F absolute Average atmospheric temperature 62 F. T, 522 F absolute Average coefficient of friction 0.016___/ -- 0.016 Average chimney gas density, 0 F, 1 . atmosphere............................................. p, - 0.09 lb per cu ft Barometer reading, sea level...............B, - 29.92 in. Hg When these values are substituted in Equations 7, 8, and 9, respectively, the results are: H - 190Dt . (io) d- 1 (ii) V, 13.7IFW* (12) These equations should be used for general operating condi tions only, or where the required data necessary for an exact determination are difficult or impossible to secure. Whenever it is posable to obtain accurate data, or the anticipated op- UotM Temperature 0 F) fig. 4.... Available Draft for 9' x 9' and 9' x 13' Masonry Chimneys ` erating conditions are fairly well known, the required size should be determined from Equations 7, 8, 9. Additional construction data for large industrial chimneys, whether brick, concrete, or steel may be found in Kent's Mechanical Engineers' Handbook* or the Handbook of Budd ing Construction.* RESIDENTIAL CHIMNEYS Since residential heating appliances depend to a large ex tent on the natural draft of residential chimneys for satis factory performance, the chimneya must be of adequate height and of optimum cross-sectional area, reasonably gas tight, and as smooth as practicable internally. They must be of such construction as to create no fire hazard to the build ing. The height and location of a residential chimney are usu ally limited by architectural and structural considerations, and therefore the draft produced will sometimes be inade quate for satisfactory and efficient operation of the fuel-burn ing equipment. The basementless house, the one-story ranch or rambler type, and the flat-roofed structure are usually restrictive, particularly with regard to adequate chimney height. The limitations of chimney height should be carefully considered to determine whether or not the type of hating equipment specified will operate property. If the available draft of the chimney is less than the draft required for the particular heating equipment specified, auxiliary mT>g such as forced or induced draft should be included. Until recently most chimneys for residences were con structed of masonry. The National Budding Code of the Na tional Board of Fire Underwriters specifies a minimum of 4 in. of masonry enclosing a fire clay flue liner. Within the past several years, however, the Underwriters' Laboratories have tested and listed as approved Type A flues, several chimneys of prefabricated construction. Their advantages, compared with masonry chimneys, are ease of installation, and usually lower cost and a greater degree of safety under abnormal firing conditions. Through the use of insulation or other means to reduce beat transfer through the chimney walls, these Type A flues usually operate at a Higher mean Chimneys and Draft Calculations 519 (Ambfcnf Temperature 60 F) fig. 5....Available Draff for 9' x 9' and 9' x 13' Masonry Chimneys temperature for a given entering temperature and therefore produce slightly higher drafts. AVAILABLE DRAFT FOR THE RESIDENTIAL CHIMNEY Equations 3 and 4 cannot readily be used for computing the available draft for residential chimneys because of the relatively greater importance of friction losses, cooling of the gases, and soot deposits in small chimneys. Eddy currents and simultaneous flow both upward and downward can oc cur in a residential chimney for very low flue-gas velocities. At present, it is best to rely on actual test data for deter mining the available draft of residential chimneys. Fig. 4 shows the available draft of nominal 9 x 9-in. and 9 x 13-in. masonry chimneys with an ambient temperature of 0 F for a range of effective heights from 5 to 32 ft, a range of enter ing flue-gas temperatures from'200 to 1000 F, and for mass flow rates of 83 and 300 lb per hr. fig. 5 shows the same information for an ambient temperature of 60 F. The avail able drafts produced by 9 x 9-in. and 9 x 13-in. masonry chimneys are equal for practical purposes over the range of mass flow from 83 to 300 lb per hr * In tests of these chimneys the smaller chimney produced slightly greater drafts in the lower end of the range of masa flow rates whereas the larger chimney produced slightly higher drafts in the upper end of the range. The chimney height for heating plants that operate on an on-off or high-fire lout-fire cycle should be selected to produce the desired draft from Fig. 5 since this class of heating system is required to operate at rated input for short periods when the outdoor temperature is 60 F. Heating plants whose fuel burning rate is gradually increased as the outdoor tempera ture decreases are not required to operate at rated input ex cept when outdoor temperatures approach design conditions. For such systems, the chimney height should be selected from Fig. 4 which shows the available draft for an outdoor temperature of 0 F since this is likely to be the more critical condition with respect to chimney draft. The available draft for outdoor temperatures between 0 F and 60 F can be ob- tained by interpolation from Figs. 4 and 5 with only slight error. . Fig. 6 is a graphical representation of the available draft for a 13-ft brick chimney with a nominal 8 x 8-in. flue liner' over a wide range of mass flow rates and for inlet flue-gas temperatures ranging from 200 to 1000 F. This family of curves is a typical group of performance curves showing that there is a certain mass flow rate that produces a maximum available draft for any flue-gas temperature. The following approximate method may alternately be used to determine the available draft for small residential chimneys, from 10 to 25 ft in height and with internal cross section areas from 35 to 55 sq in., with a maximum probable error of 15 percent at the same flow and temperature condi tions. This method is based on the chimney efficiencies' shown in Fig. 7 and the ideal draft computed from the chim ney inlet temperature. The available draft may be expressed as: '. ' . />. - nj>< (13) where . n, = chimney efficiency taken from Fig. 7 at the desired conditions of temperature and flow. Di = ideal draft, calculated from Equation 14, assuming that the barometric pressure is 29.92 in. Hg, and the ambient temperature is 60 F. ' -D. - 0.2554B.H (Jr - i) (14) where B, -- barometric pressure, inches of mercury. H =* chimney height, feet. T( -- chimney inlet temperature, Fahrenheit, absolute. T. a ambient air temperature, Fahrenheit, absolute. The day-lined brick chimney is the most commonly used chimney, but recently other building materials have been used for reasons of economy or convenience. Investigations have established that the results shown in Figs. 4 and 5 for brick FLUE-CAS FLOW-POUNDS PER HR Square Hum litter 6% * 6% in. buide. * Barometric Prvxwrv 29.92 m. Hg. Air Temperature 60 F. fig. 6.... Available Chimney Draff for 13 ft Brick Chimney*- b 520 CHAPTER 36 1959 Guide Table l____Efficiency of Short Chimneys A. Masonry Chimney* * Derived from temperature pioh. litter 8 x 8 in. outtide, 6% x inside. Height 13 ft. fig. 7.... Effect of Gas Row on Chimney Efficiency4 chimneys can be used, with slight error, for chimneys made of shale the, concrete block, or cinder block* SHORT CHIMNEYS The application of heating systems to one-story houses without basements requires special consideration because the chimneys in such houses are often made so low in height for architectural reasons that they produce insufficient draft for some kinds of heating systems. Gas-burning devices do not necessarily require a chimney for proper combustion of the gas, but the chimney must be of adequate size and height to carry the flue out of the building since it is undesirable and contrary to American Standards to have the products of combustion discharged in the living space. If.a natural- draft oil-burning device is operated with insufficient draft because of a short chimney, smoky combustion usually oc curs, pulsations are possible in the combustion chamber, the chimney or smokepipe may become blocked with soot, and the capacity of the heating equipment may be reduced to the point of inadequacy. Insufficient draft is not ordinarily the cause of smoky combustion in coal-burning heaters, but too short a chimney can cause slow pickup of the Are and insuffi cient heating capacity of the device. Based on the amount of draft usually required for present- day heating systems at rated output, any chimney with an effective height of less than 15 ft above the center line of the thimble should be regarded as a 6hort chimney. In short chimneys every precaution should be taken to attain the highest possible average temperature in the chimney and the lowest practicable friction loss. Short chimneys of conven tional construction are likely to produce from 60 to 90 per cent of the ideal draft and, therefore, the draft would only be increased from 10 to 40 percent if all friction and cooling could be eliminated.' The available draft for short chimneys can perhaps be determined most readily by using Equation 13, Mg. 8, and Table 1. Mg. 8 shows the relationship between effective chim ney height, inlet flue-gas temperature, and the ideal draft that would be produced for two values of outdoor tempera ture if there were neither friction nor cooling of the gases as they traversed the chimney. After obtaining the ideal draft for a given chimney height and entering flue-gas temperature from Fig. 8 and selecting the appropriate efficiency value from Table 1, the available draft can be computed from Equation 13. Mg. 8 can be used in reverse in conjunction with Tl ft LI Height h ft 6 to 15 Hue Go* Row Rote Ib/hr Interne! Liner Sixe, in. 7 (die) 7*7 7 * 11 end lO(dia) Efficiency, Percent 90 75-82 65-76 65-80 200 83-84 67-85 82-88 315 75-89 67-86 81-89 (Inlet Flue Gas Temp. 200 to 1000 F) B. Uimwjteted Metui Chimney* JrrT r L_1 Height ft 4 to 8 Rue Gas Row Rate ib/hr Internal Diameter, in. 6|6 Efficiency, Percent 90 90-100 | 85-95 200 * 83-88 315 | 70-80 (Inlet Flue Gas Temp. 200 to 600 F) (71 "T \T C. Metal Chimney** Uninsulated 1-in. insutation with dead air space aroend chimney 1-in. insutation Witt 1-m. open air space around chimney Efficiency, Percent 8 to 14 76 85 81 * Six-inch chimacy not recommended for these flow rates. b Internal die flue p* flow rate SO to 11$ Ib/hr; inlet floe p* temp. ZOO to 1000 F. - fig. 8.... (deaf Draft for Short Chimneys at Outside Temperatures of 0 F and 60 F Chimneys and Draft Calculations 521 efficiency values from Tabic I to determine what chimney height is required to produce the required draft at rated out put for a given heating appliance. . Fig. 7 shows that the efficiency of a given chimney varies with the maaa flow rate of gases and with the entering flue gas temperature. The efficiency also varies with the height for a given construction and depends somewhat on the method Offpd to connect the smokepipe to the chimney and the amount of exposure to the outdoor air. Experimental data are not sufficiently complete to tabulate efficiencies that take into account all of these variables. However, recommended values of efficiency for several sizes of domestic chimneys of masonry materials and of metal have been selected from the literature41 * * * and summarized in Table 1 for use with Fig. 8 in determining the available draft produced by short chim neys of 15 ft in height or lower. In parts A and B of -Table 1 - the value of efficiency chosen from the range cited should be increased as the chimney inlet temperature increases over the applicable range. In part C of Table 1 the efficiency val ues listed will yield the available draft for the range of mass Sows, inlet flue gas temperatures, and chimney height shown within 10 percent. ' . In the application of short chimneys, observance of the following precautions will assist in obtaining the highest practicable draft and may cure unsatisfactory operation of' the chimney and heating plant in certain instances: 1. Use a minimum length of horizontal smokepipe between the beater and chimney. 2. Insulate the smokepipe and the chimney itself, if made of metal. Insulation of the chimney liner in masonry chim neys reduces the heat loss from the flue gases and the in filtration of cold air. 3. Do not use an oversized chimney because larger chimneys produce greater cooling of the flue gases. - 4. Avoid downdrafts by proper construction above the roof or by the use of a suitable chimney cap. 5. Avoid the use of barometric dampers in the smokepipe of natural-draft heaters since most barometric datnpers.permit enough cold- air to leak into the chimney to reduce the draft appreciably. - 6. Avoid air leaks in the smokepipe and chimney. 7. Avoid connecting more than one heating device to a single chimney. - 8. Use construction materials of low heat capacity if the chimney draft must increase quickly for an intermittentlyfired heating device. 9. Do not operate a kitchen exhaust fan unless an air intake of ample area is used to-prevent lowering the house pressure. 10. Avoid tight utility closets so the chimney draft will not be required to do the added work of drawing combustion air into the closet from the surroundings. DETERMINING RESIDENTIAL CHIMNEY SIZES The flue sizes for small residential chimneys are governed by the National Building Code of the National Board of Fire Underwriters for gas-burning appliances. Chimney areas for liquid- and solid-fuel-buming devices are selected primarily to meet the requirements of local building codes, but these requirements are not determined by any rigorous formula based on physical principles. By calculating the available draft for the chimney in ques tion, and comparing it with the performance values of the heating unit (either natural or forced draft type) at the de sired output, it is posable to determine whether the chimney is adequate in height for the particular heating unit it serves. For calculations where the fuel rate and the percentage CO, are the only known factors, the flue gas rate can easily be determined for coal, oil, and gas from Fig. 9. By entering Fig. 9 at the percentage CO,, moving vertically to the curve for the type of fuel, and then moving horizontally to the fuel rate, the flue gas rate in pounds per hour may be determined for any fuel.* Any of the described methods of determining available draft may be used, but a graphical solution to the problem may be had for the 8 x S-in. chimney from Figs. 6, 7, and 9. This solution can be best explained by a numerical example. Example S: Determine whether a 13-ft, 8 x 8-in. nominal-size flue is sufficient for a coal-heating unit rated at 0.03 in. of water draft at 400 F inlet temperature, fuel rate being 10 lb per hr of bituminous coal, with 10 percent CO,. Solution; From Fig. 9, a flue gas rate of approximately 180 lb per hr is obtained. The available draft for a ISO lb per hr fuel rate, and an inlet temperature of 400 F, obtained from Fig. 6, is 0JQ56 in. of water. This indicates that the chimney is adequate. The selection of chimney areas for liquid- and solid-fuel burning devices is difficult because of the variability in effi ciency of different models, the possibility .that soot on the lining will restrict the chimney ares, and the variation in combustion air requirements of different solid fuels. Figs. 6 and 7 show that a given chimney produces a maximum avail able draft and a maximum efficiency for some intermediate mass flow rate for any selected inlet flue gas temperature. For mass flow rates lower than the optimum the greater cooling of the gases in the chimney causes lower available draft, whereas for mass flow rates above the optimum the greater friction losses reduce the available draft. A chimney for a given heating system should probably be designed to operate at its point of maximum efficiency and maximum available draft for its full rated output. A chimney would have an accelerating effect14 on the combustion rate of a solid-fuel burning device if it were operating to the left of the optimum point in Mg. 6 because an additional increment in mass flow rate would increase the available draft a small amount and tend to increase the *** flow still more. On the other hand, a chimney operating to the right of the optimum point in Tig. 6 would tend to decelerate the combustion rate for any small increase in mass flow rate. Data are not complete for the selection of proper chimney areas for heating plants of different capacities, but some in formation on the effect of cross-section area on the capacity of masonry chimneys is provided by tests'*11 on several chim neys with liners having nominal outside dimensions: 9-in. FLUE CAS FLOW-POUNDS PER 'HR 7.06 lb par gal, 60 F, Fig. 9.... Graphical Evaluation of Rate of fine Gas How from Percent COj and Fuel Rate* 522 CHAPTER 36 1959 Guide Table 2 .... Approximate Hue Gas How Rates For Maximum Available Draft in Masonry Chimneys Aw Go* Twpwafuw of Qwcmey Mat, F Noctmaf fate*mil Area 200 External tmr CVuwiPom, la. Sq. la. 600 1000 Mon Row Bate, Lb/Hr 200 <500 1000 Roe Gat Velocity ot Qiisney Met, Fpa 9 (dia) ' 9x9 12 (dia) 9x13 38.5 49 78.5 77 170 ISO 215 306 290 Above 320 295 Above 320 130 334 Above 320 Above 320 175 250 300 175 400 600 150 150 diameter, 12-in. diameter, 9 x 9-in., and 9 x 13-in. These tests showed that for flue gas rates up to 200 lb per hr, and entering flue gas temperatures from 200 to 1000 F, the 9-in. ' round liner provided an available draft equal to, or greater than, that produced by the other three huger liners. When the flue gas rate was increased to 320 lb per hr, the three larger liners produced a little more draft than the smallest one for entering flue gas temperatures above 600 F. Other data*- show that metal chimneys with an internal diameter of 6 in. should not be used for mass flow rates greater than 130 lb per hr. Table 2 shows approximate values of the mass flow rates and flue-gas velocities at the chimney injet that produce the m>tTTmtim available draft for masonry chimneys* of several conventional sixes and with an effective height of 15 ft. This table shows that a 9-in. round chimney is best suited to mass flow rates from 130 to 170 lb per hr, a 9 x 9-in. chimney performs best for flow rates from about 200 to 300 lb per hr; and 9 x 13-in. and 12-in. round chimneys are best suited to flow rates above 300 lb per hr. These results were obtained with clean chimneys, so that conclusions about chimney areas require some modification if soot deposits are taken into con sideration. Soot deposits in chimneys reduce the effective area of the liner and may in some cases entirely close the passage. Soot deposits are likely to be greater in the horizontal passages in the hating plant, the breeching, and the smokepipe, than in the vertical chimney liner. An increase in the liner diameter of one inch above that required for a clean chimney will probably make adequate allowance for soot deposits in all but the worst cases. Where smoky combustion is likely to occur and the wm- flow rates on a clean chimney basis ap proach those listed in Table 2, the next larger commercial size liner should be used. Smoky combustion with oil-burn ing devices, particularly with vaporizing oil burners, is likely to be caused by inadequate draft which is often due to insufficient chimney height. For coal, inadequate chimney height or chimney area may be a contributing cause, but smoky combustion with coal is related to fuel characteristics and firing methods. Therefore, an increase in chimney area will usually not cure smoky combustion of a coal-burning device, but can be expected to lengthen the interval between cleanings. New standard sizes of clay flue linings were recently devel oped by the industry and approved by the American Stand ards Association, in order to effect economies that can be derived from coordination of the dimensions of building ma terials. These linings are known as modular clay flue linings, and the dimensions and tolerances are summarized in ASA Standard A62.4-47. As the effective areas of these liners are somewhat windier than those of the corresponding linings used previously, they cannot be used in certain municipalities where building codes specify minimum areas based on the older dimensions. DRAFT REQUIREMENTS OF APPUANCES Typical flue-gas temperatures and drafts required at rated output for several kinds of domestic heating appliances1* are contained in Table 3. Chimney height and chimney area for cast-iron boilere are specified in the / = B = R Testing and Rating Code of the Institute of Boiler and Radiator Manu facturers. Mechanically-fired devices such as oil burners and stokers are equipped with blowers, and therefore, the chimney is not required to overcome the resistance of the fuel bed or burner. Nevertheless, a draft in the firebox, of about 0.03 in. of water, is desirable so that leakage, if any, will be into the firebox rather than outward from it. Insufficient draft for natural-draft appliances is likely with installations in attics or in one-story basementlesshouses. Automatic oil-burning space heaters, floor furnaces, and warm air furnaces employing natural-draft vaporizing burners re quire a draft of 0.06 to 0.08 in. water for outdoor tempera tures of 60 F. Coal-burning heaters and furnaces which attain design rating at OF outdoor temperature would require about the same draft. For such requirements, data from Fig ure 8 and Table 1 show that an effective chimney height, above chimney inlet, should be a trdnimnm of 8 to 12 ft. Be cause temperature drop and friction loss in the flue pipe can not be calculated accurately/ and the resistance of various chimney connections is uncertain, the minimum calculated heights should have a generous factor of safety applied to allow for these and other uncertainties. Where ample height cannot be provided, forced or induced draft should be pro vided. Extreme care should be used in the application of forced draft to avoid producing a pressure in - combustion Table 3 .... Drafts Required by Typical Residential Heating - Devices or Appliances Device Steele foco Draft, (a. Water pratere" F Space Heater, Oil-Burning, Pot Burner.................................................... 0.06 to 0.08 Warm Air Furnace, Oil-Burning, Pot Burner.................................................... 0.06 Warm Air Furnace, Hand-Fired........ 0.06* Floor Furnace, Oil-Burning, Pot Burner.................................................... 0.06 Mechanical Oil Burner, Less than 5 gph..................... *.................................... 0.03" Mechanical Oil Burner, More than 5 gph................................................... - 0.05* or less Cooking Stove, Solid-Fuel.............. - 0.04* Space Heater, Coal-Burning.............. 0.06* Drkil in firebox. * for cfa--taoXctwC xfrthrarite. *18 in. Iron better. 1000 880 900 860 -- -- 400 900 Chimneys and Draft Calculations * 523 chambers, because they are not usually designed to prevent the outward leakage of toxic gases which might result. Induced draft by means of motor-driven fans or blowers will solve low-draft problems, but would usually be employed for residential systems only as a last resort. Operation of a blower entails some cost, introduces maintenance require ments, and may be dangerous in event of power failure un less suitable protective devices are used. Induced draft fans designed to resist effects of high temperature and corrosion are available. Fans not carefully designed or modified to meet these conditions should not be applied to this service. CHIMNEYS FOR GAS APPLIANCES The Approval Requirements of the American Gas Associa tion are such that a gas-fired appliance must be able to op erate at its rated input (plus 10 or 15 percent) without a chimney connection, and without producing carbon monoxide. The primary functions of the chimney for the gas-fired ap pliance are to remove the products of combustion from the living space- and to assure safety to the building. The chim ney therefore becomes essentially a vent and, in fact, the vents tested and listed by Underwriters' Laboratories for use only with gas appliances were for some time HpagnatpH as Type B Gas Appliance Vents. Their use is limited to appli ances approved by the American Gas Association and oper ating with flue-gas temperatures not in excess of 550 F at the outlet of the draft hood. A draft hood is always required in connection with a Type B flue. The Type B-W gas flue is further limited to the venting of wall heaters having an input of not more than 50,000 Btu per hr. Because of the low temperatures to which gas flues are limited care should be taken to ascertain that the appliance IKS)DC DIAMETER Of flUE IN INCHES fig. 10....Capacity in Btu per Hour for Gas Appliance Flues or Vents fig. U ....Capacity of o Rectangular Rue or a Semi Elliptical Rue, with Semi-Grcular Ends Having Its ' Minimum Width Equal to the Diameter of a Circular Flue, Compared with the Capacity of the Grcular Flue is not convertible to fuels other than gas and that the appli ance is approved by the American Gas Association. It is well also to be certain that gas fuel will continue to be available to the building. Chimneys for venting appliances designed for burning gas, can therefore be low in height, but must have adequate area. The height is usually established by the building height. Chimney sizes are usually selected on the baas of heat input of the appliance. The imnmnim flue or vent sizes adopted by the American Standards Association and the National Board of Fire Underwriters in 1950 for gas appliances0 are shown in Fig. 10. Additional provisions of ASA Standard Z21.30-1950 re lating to chimney size are: 1. In no case shall the vent area be less than the area of a 3-in. diameter pipe. 2. When more than one appliance vents into a flue or vent, the flue or vent area shall be Qot less than the area of the largest flue or vent connector plus 50 percent of the areas of - the additional flue or vent connectors. 3. Any-shaped flue or vent may be used provided its flue gas venting capacity is equal to the capacity of the round pipe for which it is substituted. Since Fig. 10 has been prepared for circular flues, relative capacities for rectangular and semi-elliptical flues14 are shown in Fig. 11. Heating appliances designed to burn gas, as well as appli ances converted to gas burning, except those equipped with power-type burners and excepting conversion burner installa tions in excess of 400,000 Btu per hour input in large steel boilers, are always equipped with a draft hood attached to the flue outlet of the appliance. This draft hood is required if the appliance is to meet the approval requirements of the American Gas Association and the American Standards As sociation, and is essential for safe operation. It is designed to prevent excessive chimney draft which would lower appli ance efficiency, to prevent a blocked flue or a downdraft in the chimney from impairing combustion, to provide a relief opening for the products of combustion during downdraft or blocked-flue conditions, and to prevent spillage of the products of combustion to the space surrounding the appli ance, if there is a chimney draft equivalent to that provided by a 3-ft chimney. As the draft hood is designed without moving parts, the relief opening is always open, and conse quently some air is drawn into the chimney. This air lowers 524 .CHAPTER 36 1959 Guide the gas temperature in the ehimney, but it also lowers the dew point of the gases and tends to prevent condensation. The installation'of conversion burner equipment in large boilers is usually made in accordance with regulations of the local gas company. In such installations a definite chimney draft may be required for proper combustion, and conse quently the foregoing reference to the use of draft hoods would not apply. The products of complete combustion of gas are water va por and carbon dioxide. In the case of manufactured gas, the presence of organic sulfur compounds, generally between 3 and 15 grains*, per hundred cubic feet, gives rise -to minute percentages of sulfur dioxide and sulfur trioxide. The volume of water vapor in the fiue products from natural or coke oven gas is about twice the volume of carbon dioxide. It is ex tremely important that the chimney be tight and resistant to corrosion, not only from moisture, but also from dilute sulfur trioxide. Clay linings with joints which prevent retention of mois ture, and linings mtuift of noncorrosive materials, are advan- Table 4.... Results of Reid Survey on Chimney Damage Type of Construction Number of Chiaaeyi Number Reported Damaged Pcnwtf Domoged Chimneys without liners............ Chimneys with sewer tile con- struction............................... Wilder metal coated with as- phalt chromate emulsion... Steel costed with plastic............ Vitreous enamel on steel........... Aluminum...................................... 4720 8410 5185 9200 614 50,000 562 104 291 1928 No record 228 11.9. 1.2 5.6 21.0 -- 0.45 tageous. The interior protection of unlined chimneys by ap plying an asphalt-chromate emulsion has been investigated by some gas companies but the material is not of current in terest because insurance companies do not favor potentially combustible coatings " An investigation of damage occurring in 78,129 chimneys used for venting gas appliances in a severe climate has been made by the Minneapolis Gas Company with the results shown in Table 4 taken from Reference 15. - Advice regarding recommended practice and materials for flue connections and chimney linings can usually be obtained from the local gas company, and should be given careful con sideration. RECOMMENDATIONS OF THE NATIONAL BOARD OF FIRE UNDERWRITERS For general data on the construction of chimneys, reference should be made to the National Building Code, recommended by the National Board of Fire Underwriters, Article X, Sec tion 1001 to 1006, in which the following are some of the important provisions listed in the 1951 edition: 1. Flue Connections Required. Every heating apparatus or heat producing appliance requiring a flue connection shall be connected with a flue conforming to the provisions of this arti cle. This shall not include electric appliances; gas appliances, except as specifically required in this article; or oil fired appli ances especially designed for use without fiue connection. 2. Use of Nonconforming Flues. Flues not conforming to the requirements of this article for chimneys, metal smokestacks or vents for gas appliances, shall not be used unless listed by Underwriters' Laboratories, Inc., installed.in full compliance with the and the manufacturer's instructions, and ap proved for such use by the building official. 3. Smoke Pipe Connections. a. No flue shall have smoke pipe connections in more than one story of a building, unless provision is made for effectively closing smoke pipe openings with devices made of noncombusti ble materials whenever their use is discontinued temporarily, and completely closing them with masonry when discontinued per manently. b. Two or more smoke pipes shall not be joined for a single connection, unless the smoke pipes and flue are of sufficient size to serve all the appliances thus connected. c. The smoke pipe of a heating appliance shall not be con nected into the flue of an incinerator which has the rubbish chute identical with the smoke flue. 4. Construction of Chimneys. a. Chimneys hereafter erected within or attached to a struc ture shall be constructed in compliance with the provisions of this section. b. Chimneys shall extend at least 3 ft above the highest point where they pass through the roof of the building, and at least 2 ft higher than any ridge within 10 ft of such chimney. c. Chimneys shall be wholly supported on masonry or self supporting fireproof construction. ' d. No chimney shall be corbeled from a wall more than 6 in.; nor shall a chimney be corbeled from a wall which is less than 12 in. in thirViwMaa, unless it projects equally on each side of the wall; provided that in the second story of 2-story dwellings cor beling of chimneys on the exterior of the enclosing walls may equal the wall thicknera. In every case the corbeling shall not exceed 1 in. projection for each course of brick projected. e. No change in the size or shape of a chimney, where the chimney passes through the roof, shall be made within & dis tance of 6 in. above or below the roof joists or rafters. 5. Chimneys for Heating Appliances, Low Heat Industrial Appliances and Portable Type Incinerators. a. Chimneys for stoves, cooking ranges, warm air, hot water and low pressure steam heating furnaces, fireplaces, and low heat industrial appliances, other than chimneys for incinerators of nonportable type, shall be constructed of solid masonry units or of reinforced concrete. The walls shall be properly bonded or tied with corrosion-resistant metal anchors. In dwellings and buildings of like heating requirements, the thickness of the chimney shall be not leas than 4 in. In other buildings the thick ness shall be not less than 8 in., except that rubble stone masonry shall be not less than 12 in. thick. . b. Every such chimney hereafter erected or altered shall be lined with a flue lining conforming to the requirements below. c,,. Flue linings shall be made of fire clay or other refractory clay which will withstand the action of flue gases and resist, without softening or cracking, the temperatures to which they will be subjected, but not less than 2000 F. Flue linings may be of cast iron of approved quality, form and construction. d. Required clay flue linings shall be not les th^n % in. thick for the smaller flues, and shall increase in thickness for the larger flues. e. Flue linings shall be installed ahead-of the construction of the chimney as it is carried up, carefully bedded one on the other in Type A, Type B, or fire clay mortar with close fitting joints left smooth on the inside. f. Flue linings shall start from a point not less than 8 in. be low the intake, or, in the case of fireplaces, from the throat of the fireplace. They *hall extend, as nearly vertically as possible, for the entire height of the chimney, and be extended 4 in. above the top of cap of the chimney. g. Cleanouts for flues or fireplaces shall be equipped with cast-iron dobra and frames arranged to remain tightly closed when not in use. hi. When two or more Sues are contained in the same chim ney, at least every third flue shall be separated by masonry at least 4 in. thick bonded into the masonry wall of the chimney. Where flue linings are not so separated, the joints of adjacent flue linings shall be staggered at least 7 in. Chimneys and Draft Calculations 525 6. Sizes of Flues. a. The cross-sectional area of smoke flues shall be designed pnrf proportioned to meet the conditions of temperature, within npH without'flue, of masonry, exposure, shape and material of flue, and other influences. The National Building Code specifies lined chimneys and metal smoke stacks for all gas appliances which may be con verted readily to the use of solid or liquid fuel, and also for all boilers and furnaces, except those having a flue-gas tem perature not exceeding 550 F at the outlet of the draft hood when burning gas at the manufacturer's rating and which may, therefore, be connected to Type B vent piping. Ap proved Type B vent piping is noncombustible, corrosion-re sistant piping of adequate strength and heat-insulating value, and having bell and spigot or other acceptable joints. Fig. 10 may be used for selection of vent-pipe size.. . Important points to be considered in the use of Type B vent piping are: ' 1. Type B flues must be. plainly and permanently marked at the point where the vent connection enters the flue: For Use on Gas Appliances Only. . ' ' '. ' 2. Type B gas vents shall be installed with a clearance to combustible material or construction, whether plastered or un plastered, of not leas than one inch, provided that for vents of floor furnaces, such clearance shall be ,not less than 3 ft from the outlet of the draft hood, measured along the center line of the vent piping. Other important points that should be considered for flues and vents for gas appliances are as follows: 1. Clearances from combustible material to gas appliance rent piping other than approved Type B gas vents shall be in accordance with the Building Code Standards of the National Board of Fire Underwriters for the Installation of-Heat Produc ing Appliances,- Heating, Ventilating, Air-Conditioning, Blower, and . Exhaust Systems. 2. Every flue-connected appliance, except an incinerator, un less its construction serves the same purpose, shall be equipped with an effective draft hood which either (a) has been approved as part of the appliance or (b) complies with nationally recog nized standards for draft hoods. The draft hood shall be at tached to the flue collar of the appliance as conditions permit, and in a position for which it is designed with reference-to hori zontal and vertical planes. The draft hood shall be so located that the relief opening is not obstructed by any part of the appliance or adjacent construction. " 3. No vent pipe from a gas appliance shall be interconnected with any other vent pipe, smoke pipe, or flue, nnlew such gas appliance is equipped with an automatic device to prevent the escape of unhurried gas at the main burner or burners. Where a gas appliance vent pipe is joined with a smoke pipe from an appliance burning some other type of fuel, for connection into a single flue opening, they shall be joined by a Y fitting located as close as practicable to the chimney. With liquefied petroleum gases, the automatic device to prevent the escape of unburned gas shall shut off the pilot light, as well as the main burner or burners. Recent tests of masonry chimneys1? made of a variety of materials have 'developed additional recommendations re garding the-construction of masonry chimneys that will de crease the hazard to surrounding combustible materials. GENERAL CONSIDERATIONS FOR CHIMNEYS The draft of domestic chimneys may be subject to a variety of influences not usually encountered in power chimneys" because of the low available draft often supplied by a short chimney. Horizontal winds have an aspirating effect as they cross the chimney and are an aid to draft. However, sur rounding objects, such as trees or other buildings, may affect the direction of the wind at the chimney top, and may even direct it down the chimney, tending to reduce the draft or even to cause it to change to a positive pressure. . It is not to be assumed that increasing the cross-sectional area of a chimney will always effect a cure for poor draft. The opposite result may occur because of the cooling effect of the larger area, and the effect of recirculation of the flue gases. The flow of gases into the chimney top has been observed at low rates, and recirculation in small residential chimneys has been noted throughout the entire length of a chimney and smoke pipe, with the greater amount of recirculation occur ring at the thimble. The effect of recirculation decreases with chimney height and the increase in flue-gas velocity. It is also important to consider the course of the air supply for proper combustion. The boiler or furnace is usually lo cated in tiie basement. In the majority of cases, the furnace room has windows and doors opening to the outdoors on two or more sides of the house. Usually enough air leaks into the furnace room through these openings to sustain combustion. In some cases, however, windows and doors are so tight as to restrict the flow of combustion air, and thereby affect the correct operation of the chimney. II the boiler room is fairly tight and is open to the outdoors on only one side of the house, the draft will be affected in windy weather even with windows or doors open. If the wind is blowing toward the boiler room, the draft will be increased, but if blowing in the opposite direction, the draft may be decreased. The surrounding of a heating appliance with a restrictive enclosure that will limit entrance of combustion air is more likely to occur in a small utility closet installation on the first floor than in a basement installation. An opening with a free area approximately twice the area of the sxnokepipe should therefore, be provided between the utility closet and the living space or the outdoors. If the utility closet-is con nected to the outdoors, greater difficulty with wind pressures will be encountered. Where a draft regulator is used it should have ample communication with the amw space from which the combustion air is taken. Where forced warm air furnaces are enclosed in utility closets, care should be used to make the return air connection intide the utility closet airtight so that the blower cannot reduce the pressure in the closet and cause a downdraft in the chimney. Two or more chimneys, either large or small, should never be connected. If connected at the bottom, hot gases in the U-tube thus formed would be in unstable equilibrium. Cold air from the top would descend through one such chimney and drive the hot gases out of the other, thus annulling, the draft. More than one device can be served by one chimney. Bat teries of boilers are commonly connected to a single chimney in power plants. However, if two or more chimneys are used, each chimney should be used separately for part of the boil ers, and not connected in manifold with another chimney, in order to avoid the difficulty described previously. In domestic installations it is sometimes necessary to serve a space heater or cooking stove and a water beater with the same chimney flue. Tins is not desirable, especially for low chimneys, since doors left open on one device, while it is un fired, will tend to annul the draft on another device. Gas burning devices, with their draft hoods and lack of draft dampers, are especially bad in this respect. The traditional method of avoiding this with brick chimneys has been to construct multiple-flue chimneys, so that each fuel-burning device could be served by a separate opening. If two devices must be served by one flue-opening in a chimney, their con nections to the chimney should not be located opposite each 526 CHAPTER 36 1959 Guide other. The connection from the larger device should be rea sonably low, and that from the smaller should be up near the oeiling, so that each device can be serviced as well as possible, regardless of the treatment of the other. Even where such precautions are taken, there is, under unusual conditions, some possibility of flow of combustible gases from one appliance into another. Reverse flow of cooled gases has been demonstrated in a chimney at very low rates of flow/ Under certain similar quiescent conditions, acci dental discharge of combustible gases from a defective device into a chimney could result in flow of these gases counter current into the combustion chamber of another device at tached to the same chimney. If ignition occurred in this sec ond device, an explosion could result. .' Excessive height in a chimney does no harm, but meana for controlling the draft are more than ordinarily if the chimney is too tall. Coal-burning devices often have air leaks around the firebox, and the. draft doors sometimes fit so poorly- that the fire cannot be controlled at a low rate. The amplest remedy for such cases is the barometric damper which admits air into the flue pipe and thus reduces draft. Where a chimney serves a fireplace, it is important that no other heating device be connected to it unless the fire place is effectively sealed. - REFERENCES *R. H. Sherlock and B. A. Stalker: A Study of Flow Phe nomena in the Wake.of Smokestacks' (University of Michigan, Department of Engineering Research Bulletin No. 29, 1941). * E. F. Miller and James Holt: Notes on Power Plant Design (Massachusetts Institute of Technology, 1930). 'L. F. Moody: Friction factors for pipe flow (ASME Trans actions; Vol. 66, 1944, p. 671). 4 R. T. Kent (ed.): Mechanical Engineers' Handbook (John Wiley A Sons, New York). *G. A. Hooi and N. G. Johnson: Handbook of Building Con struction (McGraw-Hill Book Co-, New York, 1929). * R. S. Dill, P. R. Achenbach, and J. T. Duck: Observed per formance of some experimental chimneys (ASHYE Trans actions, Vol. 48, 1942, p. 351). r L. B. Schmitt and R. B. ; Performance of residential chimneys (ASHVE Transactions, Vol. 55, 1949, p. 241). *P. R. Achenbach and S. D. Cole: Performance of fourteen masonry chimneys under steady state conditions (ASHVE Transactions, Vol. 55, 1949, p. 129). ' *R. D. Thulman and W. H. Shenkle: A theoretical and ex perimental investigation of the performance of some short flues under steady-state conditions (Thesis at Massachusetts Insti tute of Technology, June 1951). '' "P. R. Achenbach: Physics of chimneys (Physics Today, Vol. 2, December 1949). . " R. K. Thulman: Performance of Masonry Chimneys for Houses (Housing and Home Finance Agency Technical Paper No. 13, August 1949). - " CS101-43 Oil-Burning Space Heaters Equipped with Va porising Pot-Type Burners, CS75-42 Automatic Mechanical Oil Burners Designed for Domestic Installations, CS(E)104-43 Warm Air Furnaces Equipped with-Vaporiemg Pot-Type Bum-, ert, CS109-44 Solid-Fuel Burning Forced Air Furnaces} C8U3-44 On-Burning Floor Furnaces Equipped with Vaponxihg Pot- Type Burners (National -Bureau of Standards Commercial Standards). - ... - . TM American Standard Installation of Gas Piping and Gas Appliances in Buildings (American Standards Association, Z2130-1950). . .. "Comfort Heating (American Gas Association, 1938, p. 71). " C. G. Segeler: Siting of Chimneys and Flues Used for Gas Appliances (American Gas Association; Sixth International Gas Conference, 1955). . "N. D. Mitchell: Fire, hazard tests with masonry chimneys (National Fire Protection Association Quarterly, October 1949). . "S. Konso: Chimneys and draft (Winter Air Conditioning, National Warm Air Heating, and Air Conditioning Association, 1939, Chapter 32). .. CHAPTER 37 ESTIMATING FUEL CONSUMPTION FOR SPACE HEATING flaxes of Fuel Estimates; Efficiency of Utilization; Calculated Heat Loss Method.- Computation and Application, Short Methods for Estimating Heat Loss; Degree-Day Method: Computation and Application, Unit Fuel Consumption per Degree Day, Estimating Consumption for Various Fuels, Degree Day as an Operating Unit; Industrial Degree Days; Maximum - Demand and food Factors IT IS often necessary to estimate the anticipated heat re the heat in the fuel is used. Efficiency can be defined in quirements and fuel consumptions of heating plants for a variety of ways for various purposes, and the values either short or long terms of operation. These quantities can in any given case vary widely depending on the con be much more difficult to calculate than design heat loss or ditions. For estimating purposes, as will be shown later, it required system capacity, since they involve essentially the is the eflvctency of utilization of the fuel over the calculation summing up of.the net result over the period in question of . period which is wanted. This is distinct from furnace efficiency the influence of many factors which may vary greatly with which expresses the heat delivered by a furnace unit as a per time. It will seldom be possible to predict with any great ac centage of the heat provided in the fuel and which is the curacy the way in which all the factors involved will vary efficiency normally used in describing the performance of throughout the prediction period. In addition to this, the cal a unit under rated, or stated, load conditions. It has been culations required to-take all such variations into account shown, at the University of Illinois for example,1 that in the become very involved. For these and other reasons records case of a dwelling with an inside chimney, as much as 35 of past operating experience, when these are available, pro percent of the heat delivered to the chimney which is nor vide the most reliable and usually the most accurate basis mally considered to be a loss so far as efficiency of the fur for the prediction of future requirements. ' nace is concerned may be delivered to the house through the Records of past heat requirements or of fuel consumption heated chimney walls. This recovered heat amounted to as of a particular building are a better basis for estimatesthan much as 12 percent of the heat required by a house. Much are averages of records from similar buildings. In the absence of this recovered heat may be available for heating. It has of past records for a particular building the data from sim been said in connection with the same study that at times ilar plants in the same locality may have to be used. Averages . only about 50 percent of the heat utilized by a house was of consumption figures taken from many types of plants in supplied by radiators, while the other 50 percent of the many types of buildings in various localities can only pro heat utilized was supplied from such sources as chimney, duce an average estimate which may prove to be inaccurate piping, boiler jacket and smoke pipe, people, lights, etc. A when applied to a particular building. summary** * of many tests in two research residences at the Where unusual operating conditions exist due to factors University of Illinois using many fuels and systems give such as excessive ventilation, abnormal inside temperatures, values of 67 to 90 percent for overall house efficiency (the and beat gains from external sources, or where, in the ease of ratio of the heat loss from the structure to the heat input proposed buildings of unusual design, no information is avail to the unit for an average day). able regarding former consumption, it is necessary to estimate The efficiency of utilization of the fuel burned can at times fuel consumption from the computed heat losses. be relatively very high for houses. It can also vary quite In preparing fuel consumption estimates it is well to real widely from one house to another because of variations in ize that any estimating method used will produce a more chimney location and design, in the utilization of heat lost reliable result over a long period operation than over a to the basement from the heating unit and smoke pipe, and short period. Nearly all of the methods in common use will for other reasons. The efficiency of utilization may also vary give trustworthy results over a full annual heating season, with time of year as the average load on the furnace varies. and in some cases such estimates will prove consistent within Some of the reasons for this in the case of intermittently themselves for monthly periods. As the period of the estimate - fired oil furnaces have been demonstrated.4 is shortened, there is more chance that some factor not taken In buildings other than houses the efficiency of utilization into account directly in the estimating method will deviate of the heat supplied in the fuel may also vary widely. There from its long-time average value, and thus lead to serious will, in general, be less tendency in many larger buildings error in the predicted heat requirement. toward effective use for heating purposes of the heat which is normally lost from chimney, furnace, and piping surfaces, EFHCIBnICY of utilization and efficiency is seldom likely to be as high as in the case of many houses. Any method of estimating fuel requirements based pri The average fuel consumption of various types of ap marily on calculation of heat losses must, of necessity, also proved gas-fired equipment has been obtained from a large take into account considerations of the efficiency with which number of heating systems.* Corresponding efficiencies of 527 528 CHAPTER 37 1959 Guide utilization over the heating season can be calculated from these data. They show a variation from approximately 72 to 88 percent depending upon the type and size of system. Laboratory tests on a gas conversion burner in a heating boiler operated with on and off cycles gave about 72 percent efficiency* Other tests on coal-fired room heaters indicated,' fox the hp*t.ng season, efficiencies of 65 to 75 percent, when the heat from the flue pipe was included.* A survey of. 30 . residences in one locality showed a variation of 45 to 75 per* cent in utilization efficiency, depending upon the condition of tiie equipment and the fuel used.' Experience at the University of Illinois was used in es tablishing overall efficiencies for a tabulation of the compara tive costs of heating the same building with various fuels to be found in a publication of the Small Homes Council.'- - - - The efficiencies of utilization - over the heating season shown in Table 1 are suggested as a guide. Considerable Table 1 .... Efficiency of Utilization Over the Heating Season Type of Fuef-Bomeg Umf Efficiency, Poreoat Gas, designed unit ........................................ Gas, conversion unit...................... ............. Oil, designed unit........................................ Oil, conversion unit.............. ...................... Bituminous coal, hand-fixed with controls. Bituminous coal, band-fired without con trols................. .............................................. Bituminous coal, stoker-fired...................... Anthracite, hana-fired with controls......... Anthracite, hand-fired without controls.. Anthracite, stoker-fired................................ Coke, hand-fired with controls__ Coke, hand-fired without controls Direct electric heating.................. 76-80 60-80 66-80 60-80 60-65 40-60 50-70 60-80 50-65 60-80 60-80 50-65 100 judgment may have to be exercised in selection of appro priate values for any given case of fuel consumption calcu lations. '' CALCULATED HEAT LOSS METHOD The quantity of fuel or energy required for heating may be found by the Calculated Heat Loss Method from the equa tion where F = quantity of fuel or energy required (in the units in which C is expressed) X " average heat requirement for the period under con sideration, Btu per hour. ' fi rm number of heating hours in estimate period (for. an Oct. 1-May 1 heating season, 212 days X 24 hr *=* 5088). B ** efficiency of utilization of the fuel over the period, expressed as a decimal; not the efficiency at peak.or . rated load condition. C TM heating value of one unit of fuel or energy. - The value of X is usually found from the equation Hit - O X- U-L (2) where H calculated heat loss including infiltration loss, Btu per hour, based on t, and U t " average inside temperature maintained during heating period, Fahrenheit. . U TM average outside temperature through estimate period, Fahrenheit (for U. S. cities with an Oct. l~May 1 heat ing season--see Table 2). U * indoor design temperature, Fahrenheit (usually 70 F). t, -- outdoor design temperature, Fahrenheit (see Table 2). so that the value of F becomes Hit - ON B(U- U)C (3) The calculation of X, the average heat requirement, Btu per hour, over the period under consideration is given only approximately by Equation 2, when the value of H used is ' the calculated maximum load, or design heating load for the building, as computed by the methods outlined in Chapters 9,11, and 12. This value is commonly used since it is usually available from the heating system design calculations. This procedure will usually lead to values of X which are too high. In the first place, the design wind speed on which such cal culations are based is usually higher than the average wind speed for the period so that infiltration losses may be over estimated. In addition there will usually be many sources of heat not *.Vpn into account in the estimation of maximum heat riemapd which may actually contribute to the heating and thus may decrease the fuel or energy required for heat ing without necessarily affecting the maximum heat demand. The more important sources-are solar radiation, people, lights, and equipment. Improved estimates of fuel requirements will result if H can be recalculated so as to be more representative of average conditions over the heating period rather than the maximum conditions used in hparing load estimation. Further improvement may be obtained at the expense of more in volved calculations by making estimates of the average heat gains, and deducting these from the calculated heat losses. There is a practical limit to the refinement in calculations which should be attempted since there will always be some factors which are only approximately known. The weather, for example, very largely determines the heat losses, but will normally be described only approximately in terms of aver age values of a limited number of weather elements. Wind speed, and sunshine will not necessarily be distributed uni formly over periods of different outdoor temperatures. In ad dition there is a limit to the accuracy of prediction of the weather elements over the period of interest which is always in the future. For these and other reasons, including such unpredictable factors as the way in which windows and doors will be opened and closed, the determination of H or of X must always be in the nature of an estimate only. Values of the average outdoor temperature, U, are re quired for the calculation of X by means of Equation 2. Such values for the period October 1 to May 1 are given for U. S. cities in Table 2. The assumption of an Oct. 1-May 1 heating season is reasonably accurate in the well-populated New York-Chicago zone but heating may be required over a longer period for points as far north as Minneapolis, and over a shorter period south of Washington, D. C. Conse quently values taken from Table 2 may have to be adjusted (Text continued on p. 634-) Estimating Fuel Consumption for Space Heating 529 Table 2 .... Average Monthly and Yearly-Degree.Gays for Gfies in tfio-UrJtod States and Canada (Base 65 F) Sfo*t Station Montgomery....... V Year* No. of Arg. Seo- Winter Mr Aug. Sep*. Temp.d 52.3 51.8 58.9 56.4 0 0 17 <J it 13 000 000 u00 000 Ocf. Nov. One. fa". Feb. Mar. Apr. May June Yecrfy Total 118 438 614 614 485 381 12S 25 223 396 598 623 491 378 128 30 28 219 3/6 416 304 222 47 0 23 198 357 412 290 209 40 0 69 304 491 517 388 288 80 (.1 55 267 458 483 360 265 66 0 0 2820 0 2780 0 1612 0 1529 0 2137 a 1954 Flagstaff............... A Phoenix................C Yuma....................A 35.9 59.5 57.7 62.5 49 78 243 000 (J 0 0 000 586 876 1135 1231 1014 949 687 465 212 7525 22 223 400 474 309 196 74 0 u 1698 13 182 360 425 275 175 62 0 0 1492 0 105 269 318 167 88 14 0 0 951 Bentonville............. 06/07-40/41 35 Little Rock..........A 1 1 38 216 516 810 879 716 519 247 86 7 4036 0 0 9 131 435 698 775 571 418 127 24 c 3188 u 0 10 110 405 654 719 543 401 122 18 0 2982 Calif.. Fresno.................. A Independence.........' 98/99-40/41 43 Los Angeles......... C Needles................... Point Reyes........... Red Bluff............. A Sacramento......... A 17/18-38/39 98/99-40/41 22 43 San Diego............A San Francisco___C San Jose............... C 49.3 59.3 52.9 53.0 54.2 53.5 267 248 264 000 0 0 28 31 22 66 0 0 17 (J 0 0 36U 336 263 0 (J 0 0 91 22 (J 9 17 11 7 24 144 136 101 189 177 110 7 11 28 335 411 508 552 465 493 432 375 282 4632 86 345 6M1 629 400 304 145 43 0 2532 216 512 776 799 619 477 267 m 18 3834 87 2WJ 301 378 305 273 185 121 56 2015 41 140 253 328 244 212 129 68 19 1451 19 217 416 447 243 124 26 3 0 1495 282 317 425 467 406 437 413 415 363 4474 59 319 564 617 429 336 177 51 0 2546 98 357 595 642 428 348 222 103 7 2822 75 321 567 614 402 317 19C 85 5 2600 52 147 255 317 247 223 151 97 43 1574 174 318 4X7 530 398 378 827 264 164 3421 128 237 40t 462 336 317 279 24? 18C 3069 9/ 270 450 487 342 308 229 137 46 2410 Denver................. A Denver................. C Durango.................. Grand Junction.. A Pueblo...................A 04/05-40/41 07/08-40/41 37.0 37.9 _37 39.9 34 5 11 120 (] 5 103 26 37 201 (1 9 36 289 332 509 0 0 74 425 771 1032 385 711 958 535 861 1204 333 792 1132 841 1139 1413 ' 383 771 1051 1125 924 1042 854 1271 1002 1271 924 1470 1285 1104 865 843 797 859 738 1245 775 525 286 65 6132 492 266 60 5673 615 394 139 7143 402 145 23 5796 9W 74( 434 10678 456 203 27 5709 Hartford...............A New Haven......... A 0 14 101 384 699 1082 1178 1050 871 528 201 31 6139 0 18 93 363 663 1026 1113 1005 865 567 261 52 6026 D. C... Washington......... A Washington......... C 43.4 0 0 37 237 519 837 893 781 619 323 87 0 4333 0 0 32 231 610 831 884 770 606 314 80 0 4258 Fla....... Apalachicola........C Jacksonville........ C Key West............. A Key West............. C Miami .-.1............. A Miami................... C Pensacola............. C Tampa..................A 60.9 60.6 62.0 72.5 73.1 71.4 59.7 000 990 cc0 9c0 Cc0 (f0 Cc0 9 9 0 000 17 154 304 352 263 184 33 0 0 1307 16 148 m 331 247 169 2S C C 1243 11 129 276 302 226 154 14 ( C 1113 9 9 22 34 25 8 ( ( ( 89 C t IS 24 24 1 ( ( ( 77 ( i 52 61 41 12 ( ( ( 178 c 5 4# 57 48 15 C c ( 173 li 177 33? "38J 275 2(E 45 ( ( 1435 0 60 163 201 148 102 0 0 0 674 Ga........ Atlanta................. A Atlanta................. C Augusta................A Macon................... A Savannah............. A Thomasville........... 05/0^-40/41 36 56.7 0 0 8 110 393 614 632 512 404 133 20 0 2826 C 9 8 107 381 611 632 515 392 135 2? ( 2811 c C 0 54 282 494 521 412 m 62 ( ( 2238 c 9 0 28C 481 491 39J 275 62 ( ( 2049 c 9 0 34 225 412 424 .331 238 ( ( 1710 0 0 2 48 208 361 359 299 178 52 5 1 1513 Idaho.. Boise.....................A Lewiston.............. APocatello..............A 39.8 35.0 0 0 135 389 762 1054 1169 868 719 453 249 92 5890 ( ( 133 409 747 961 106i 815 668 404 222 5483 0 0 183 487 873 1184 1333 1022 880 561 317 13b 6976 111..:... Chicago................ A Peoria...................A Springfield........... A Springfield........... C 35.1 37.3 37.7 39.8 0 0 90 ( 1] 86 ( 6 83 ( 9 66 3756 350 765 1147 1243 1053 868 507 229 5ft 6310 331 751 112 124( 1024 824 435 192 41 6087 315 72 1066 11 95i 764 40? 17] 32 5693 251 66b 101- 1116 90i 712 35( 127 14 5225 * Debt (or United State* cities from a publication of the United States Weather Bureau. Jfa4Uy Normal Ttmptrahem, Pneipitaticn and Dcgrw Dope. ISM. are for the period 1S31 to 1950 usdnaive. Tboee United Btatea cities for which yean are gives is Column S are not listed is the above publication and tbe data are thoee which were computed by the United States Weather Bureau in 1940 and 1947 in accordance with the requirements of the National Joint Committee oa Weather Statistics. ^ Data for airport stations, A, aad city stations, C. are both (ton when available. ' * Data forCanadian dties vers computed by tbs Meteorological Division. Department cf Transport from normal monthly mean temperatures,adjusted for the sum mer months by a method described by H. C. 8. Thom, Tbe Rational Relationship between Heating Degree Days and Temperature, IfsatUy Wsobksr Rcbmw Vnl. 83. No. 1, January 1954. - d For period October to April, inclusive. 530 CHAPTER 37 1959 Guide Table 2 .... Averogo Monthly and Veorfy Degree Days for Gties in the United States and Canada (Base 65F) (Continued) tarnState Station no. of Arg. * Yean ' Soo- Winter Mr A0. Sopf. Oct Nor. Ok. tan. Feb. Mar. om faapd Mcjr Yearly feta/ Ind....... Evansville........... A Fort Wavne......... A Indianapolis. ...A Indianapolis........C Royal Center......... Terre Haute........A 18/19-31/32 14 45.1 37.6 39.0 39.6 0 0 59 ( n 107 ( ( 79 ( < 59 1] It 116 0 b 77 215 570 871 939 770 589 251 90 6 371 ?H 1122 12X 1036 874 516 306 705 1051 112 9 772 432 176 30 241 642 986 lu51 89! 725 375 14( 16 371 74( 1104 1235 976 860 502 245 54 295 681 1023 1107 913 725 371 145 24 6360 Iowa... Charles City........C Davenport........... C Des Moines......... C Dubuaue..............A Keokuk................... Sioux City........... A 98/99-41/42 44 31.2 37.0 35.4. 36.4 34.6 39.3 17 30 151 f 7 79 f 12 99 ( 6 89 ! 2! 149 1 3 71 8 17 128 444 912 1352 1494 1240 1001 537 256 70 32( 751 1143 1262 1044 834 432 175 35 6091 355 798 120! I33C 1092 86! 43! 201 45 346 771 117! 130! 1072 84< 425 18! 41 6274 444 882 129C 1414 1187 98! 54! 261 76 7271 30! 6HT 1073 1191 1025 761 391 136 18 5663 405 885 1290 1423 1170 930 474 228 54 7012 Kan-- Concordia............ C Dodge City......... A Iola.......................... Topeka................. A Topeka................. C Wichita.................A 05/06-40/41 36 40.7 42.1 0 0 55 277 687 1029 1144 899 725 341 146 20 5323 t c 40 262 m 98C 107f m 694 341 135 5058 C 1 40 238 67J 93C 1026 811 599 281 9! 8 4616 C 8 59 2/1 672 1017 1125 885 694 32C 131 15 C l 42 242 631 977 108! 851 669 295 111 1! 4919 0 0 32 219 597 915 1023 778 619 280 101 7 4571 Ky........ Louisville............. A Louisville............. C Lexington....... A 45.1 0 0 51 232 579 871 933 778 611 285 94 5 4439 c C 41 2oe MS 84* 911 762 605 27( 86 0 4279 0 0 66 259 636 933 1008 854 710 368 140 15 4979 La......... New Orleans........A New Orleans........C Shreveport...........A 60.6 61.6 000 c60 000 7 169 308 364 248 190 31 0 5 141 283 341 ?2! 163 19 0 0 1175 53 305 490 550 386 272 61 0 0 2117 Me........ Eastport............... C Greenville............... Portland...............A 07/08-40/41 42/43-45/46 38 31.5 141 136 281 69 113 315 33.0 15 56 199 521 798 1206 1333 1201 1063 643 1012 1464 1625 1443 1251 515 825 1237 1373 1218 1039 774 524 288 842 468 194 693 394 117 9439 7681 Md....... Baltimore.............A Baltimore............. C 44.1 44.3 0 0 50 278 582 908 955 840 676 378 115 5 4787 0 0 29 207 489 812 880 776 611 326 73 0 4203 Mass... Boston..................A Fitchburg............... 98/99-40/41 43 Nantucket........... A 0 7 77 12 29 144 22 34 111 315 618 998 1113 100? 849 534{ 236 5791 432 774 1139 124G 1137 940 572 254 70 6743 372 615 924 1020 949 880 642 394 139 6102 Mich... Alpena..................C Detroit Willow Run................. -.A Detroit City....... A Eecanaba............. C Grand Rapids___A Grand Rapids___C 29.6 27.3 36.0 50 85 215 0 10 96 0 8m 62 95 247 14 29 144 0 20 1US 530 864 1218 1358 1263 1156 762 437 135 8073 393 759 1125 1231 1089 915 552 244 551 6469 381 747 1101 1203 1072 927 55S 251 60 555 933 1321 1473 1327 1203 804 471 166 8657 462 822 1169 1287 1154 1008 606 79 7075 394 756 1107 1215 1086 939 546 248 58 6474 Lansing................ A Ludington............... Marquette........... C Sault Ste. Mane. A 42/43-45/46 45 12/13-40/41 .29 Minn . . Duluth..........;.. .A Duluth;............... C Minneapolis......... A Moorhead............... Saint Paul........... A 98/99-40/41 43 28.3 26.0 70 94 288 13 33 140 41 55 182 69 87 236 109 126 298 24.3 56 91 298 66 91 277 8 17 157 20 47 240 12 21 154 582 965 1355 1535 1421 1251 55 813 1175 1277 1142 986 472 794 1135 1271 1183 1056 543 m 1299 1435 1291 1181 639 1005 1398 1587 1442 1302 820 474 195 287 698 153 789 846 499 224 .9030 6982 7458 8529 9475 651 1140 1606 1758 1512 1327 614 1092 1550 1696 1448 1252 459 960 1414 1562 1310 1057 607 1105 1609 1815 1555 1225 459 951 1401 1553 1305 1051 846 474 178 am 487 200 570 679 327 98 564 256 77 9937 9574 7853 9327 7804 Miss---- Corinth................... 09/10-40/41 32 Meridian.............. A Vicksburg............ C 56.8 0 1 13 142 418 669 696 570 396 149 32 3087 0 0 0 90 338 528 561 413 309 85 9 0 2333 0 0 0 61 268 456 507 374 273 71 0 0 2000 Mo.- Columbia............. A Hannibal.................. Kansas City........A Saint Louis......... A Saint Louis......C Springfield........... A Billing.................a Havre................... C 98/99-40/41 43 Kalispeli.............. A 41.1 42.3 43.6 34.9 28.4 31.6 31.6 0 6 62 1 3 66 0 0 44 0 0 45 0 0 38 0 8 61 8 20 194 20 38 270 36 66 320 61 78 359 47 83 326 262 654 989 1091 .876 698 288 652 1037 1139 980 710 240 621 970 1085 851 666 233 600 927 1017 820 648 202 570 893 983 792 620 249 615 908 1001 790 632 497 876 1172 1305 1089 958 564 1023 1383 1513 1291 1076 617 999 1311 1469 1165 1017 598 969 1215 1438 1114 992 639 990 1249 1386 1120 970 326 135 14 374 128 15 292 111 8 297 101 11 270 94 7 295 118 16 564 304 119 597 313 125 654 399 197 660 427 225 639 391 215 5113 5393 4888 4699 4469 4693 7106 8213 8250 8126 8055 t Estimating Fuel Consumption for Space Heating 531 Table 2 .... Average Monthly and Yearly Degree Days for Cities in the United States and Canada (Base 65 F) (Continued) State Station ' ' Yean No. of Arp. Sea Winter tafr Avg. Sept. Oct. Nor. Oec. tons Temp-* tan. Feb. Mar. Apr. May tane Yearly Total Missoula.............. A 27.6 6 11 187 525 966 1373 1516 1257 1048 570 285 106 7850 22 57 292 623 993 1283 1414 1100 939 609 365 176 7873 Neb.... Drexel...................... 15/16-25/26 11 Lincoln.................A' North Platte....... A Valentine............. C 35.6 37.0 33.6 4 6 95 0 12 82 G 7 79 7 11 120 0 5 88 11 10 145 405 788 1271 1353 1096 843 493 219 38 6611 340 774 1144 12/1 1030 822 401 190 38 6104 31G 741 1113 1240 1000 794 377 172 32 5865 425 846 1172 1271 1016 887 489 243 59 6546 331 783 1166 1302 1058 831 389 176 32 6160 461 891 1212 1361 1100 970 543 288 83 7075 Reno..................... A Tonopah................. Winnemucca........A 38.0 27 61 165 G 5 96 0 17 180 443 744 986 1048 804 756 519 318 165 6036 422 723 995 1082 86G 763 504 272 91 5813 608 822 1085 1153 854 794 546 299 111 6369 N. H... Concord............... A 11 57 192 527 849 1271 1392 1226 1029 660 316 82 7812 N. J-... Atlantic City. .. . C Cape May............... 98/99-31/32 34 Sandy Hook........... 15/16-40/41 26 Trenton................C 42.3 41.2 42.0 0 0 29 230 507 831 905 829 729 468 189 24 4741 1 2 38 221 527 852 936 876 737 459 18! 3! 4870 (J G 47 301 603 961 1039 932 76(1 451 14! 11 5252 1 2 40 aw 572 921 1016 973 833 499 206 31 5369 0 0 55 285 582 930 1004, 904 735 . 429 133 11 5068 N.M... Albuquerque........A Roswell.................A Santa Fe................. N.Y... Albany................. A Albany................. C Binghamton........ A Binghamton........ C Buffalo................. A 98/99-45/46 43 49.1 35.2 34.7 0 0 ' 10 <: C 8 12 15 129 o' 24 139 c 6 98 1C 6! 192 f1 3f 141 16 30 122 218 630 899 970 714 589 289 70 0 4389 166 501 75G 787 56G 443 185 . 2! G 3424 451 772 1071 1094 892 786 544 297 60 6123 443 780 1197 1318 1179 989 597 246 50 6962 a# 70! 1113 1234 noa 905 53J 202 31 6319 51! 834 122! 1342 1215 1051 672 31! 8! 7537 42! 735 1113 121! HOG 927 571 24C 4! 6556 433 753 1116 1225 1128 992 636 315 72 6838 Canton.................... Ithaca.................. 1. New York La Guardia-----A New York.......C New York Central Park Obs............. 06/07-45/46 99/00-42/42 40 29.5 44- 34.9 41.1 27 61 219 17 4C 156 C C 28 G C 39 0 0 31 550 898 1368 1516 1385 1139 695 340 107 8305 451 771 1129 1236 1156 97! tiOt 292 8! 6914 25C 54C 90! 992 907 76C 441 141 1C 4989 263 561 90! 995 901 753 45C 15! 1! 5050 250 552 902 1001 910 747 435 130 7 4965 Oswego.................C Syracuse.-............ A 34.4 20 39 139 S 34 m 0 29 117 430 738 1132 1249 1134 995 654 355 90 6975 4411 759 1141 1249 114! 992 615 28* 54 6863 396 714 1113 1225 1117 955 570 247 37 6520 N. C.. Charlotte............. A Hatteras...............C Manteo.................... Raleigh.................A Raleigh.................C Wilmington......... A 04/05-28/29 25 46.1 50.0 54.6 0 0 50 262 552 769 794 678 572 285 105 5 4072 c C 7 147 43! 682 704 577 44S 172 29 C 3205 0 G 0 63 244 481 527 487 394 171 25 C 2392 G C 7 113 35! 595 642 594 469 249 75 7 3109 C C 16 149 43! 701 732 61! 477 202 41 C 3369 0 C 10 11! 387 651 691 577 44G 172 29 C 3075 0 0 0 73 288 508 533 463 347 104 7 0 2323 N. D... Devils Lake.........C Grand Forks........... Wiiliston.............. C 12/13-40/41 42/43-45/46 33 22.9 21.7 24.5 29 37 227 47 61 276 32 6(1 274 29 42 261 598 W9fc 1535 1730 1464 1187 654 1197 166! I860 1576 1314 663 1160 1681 1895 160! 1298 605 1101 1528 1705 1442 1194 657 355 116 76C 394 137 71! 35S 123 663 360 138 9033 9940 9871 9068 Ohio. .. Cincinnati........... A Cincinnati........... C Cincinnati Abbe Obs...................... Cleveland............ A Cleveland.............C 43.0 37.2 0 6 77 G C 42 C c 56 C 1G 75 0 9 60 295 648 973 1029 871 732 392 149 23 5195 222 567 88G 942 812 645 314 10! 0 4532 263 612 930 989 846 682 347 132 13 4870 340 692 1057 1132 1019 874 631 223 4G 6006 311 636 995 1101 977 846 510 223 49 5717 Columbus.............C Dayton................ A Toledo................. A Okla.... Broken Arrow........ 18/19-30/31 13 Oklahoma City..(J 38.2 40.4 38.0 35.7 47.9 0 8 69 G G 59 0 5 74 G (1 66 Q 12 102 G G 28 0 G 14 0 0 12 337 693 1032 1094 946 781 444 180 31 5615 292 654 983 1051 907 741 40! 15! 22 5277 324 693 1032 1094 941 781 435 179 39 5597 327 684 1039 1122 997 853 513 217 41 5859 3K7 756 1119 1197 1056 905 555 245 60 6394 169 513 805 881 646 506 212 61 5 3828 154 48G 769 865 650 490 182 Ml 03 644 149 459 747 843 630 472 169 38 0 3519 Ore.---Medford...............A 35.2 25 47 255 518 852 1138 1268 972 837 591 384 200 7087 0 0 77 326 624 822 862 627 562 381 207 69 4547 532 CHAPTER 37 1959 Guide Table 2 .... Average Monthly and Yearly Degree Days for Giles in the United States and Canada /Base. 65F) (Contented) State Station Ywn No. of $tortits Wort.r My Aog. S*rt. Tmp.4 Oe*. Nor. ^ Ok. Jen. feb. Mar. Apr. Mo, June Yoorfy Tafcd Ore.___ Portland...............A Portland......... .. ..C Roseburg..............C 44.3 46.1 46.7 25 22 116 11 If #5 14 10 98 319 585 750 856 AW 570 396 242 93 4632 281 KV 7tV 79' M* 515 341 19! 7< 4143 288 531 694 744 563 508 366 223 83 4122 Pa......... Erie................,.. .C Harrisburg........... A Philadelphia........A Philadelphia........C Pittsburg AUe- gheny................ A 37.3 41.4 42.7 0 17 76 352 672 1020 1128 ices 911 573 273 55 6116 ( l 69 am 6 9A 1051 92; 7S( 421 128 If 5258 ( < 47 m 571 902 981 871 70< 402 104 ( 4866 ( ( 33 21* 511 8 9X 831 667 364 S3 l 4523 0 ft 18 336 678 1004 LQ73 955 784 447 167 27 5555 Pittsburgh Greater Pitts- burgh.................A Pittsburgh............C Reading................ C Scranton.............. C 38.7 40.9 41.2 37.7 < 21 94 ( ( 56 { 6 5/ 0 18 115 XT, 721 tos 1116 981 811 481 195 31 5905 29> 612 92f 992 87! 735 402 13! i: 5048 285 581 936 mr; W? 725 411 122 ii 5060 389 693 1057 1141 1028 859 516 196 35 6047 R. X.... Bloch Island. --A Narragansett Pier. Providence........... A Providence......... C s.c.... Charleston......... A Charleston......... C Columbia........... A Columbia........... C Due West................ Greenville............ A 98/99-17/18 21/22-31/32 20 11 40.1 37.5 55.0 W.4 54.4 49.2 a 21 88 ] 2e 12i < 21 KI7 0 7 68 000 ll0 cc0 l(0 tl9 0 0 10 330 591 927 1026 955 865 603 335 96 5843 366 691 1012 1115 107f 916 62? 342 111 6397 381 672 urn 1125 1011 87f 57( 251 51 6125 330 624 986 1076 972 809 507 197 31 5607 52 270 456 472 379 281 63 0 3f 2H 41( 445 365 26( 4` < 82 33t 55f 5# 461 34( si ( ve 301 538 441 3U r, < 142 391 59f 651 491 41] 151 .3! 131 411 648 673 552 442 161 32 0 1973 ( 1769 < 2435 < 2284 2 2890 0 3060 8. D-- Huron................... A Pierre....................... Rapid City.......... A 98/99-40/41 42/43-45/40 47 10 16 149 i 11 13ft 32 24 193 472 975 1407 1597 1327 1032 558 279 80 7902 431 887 1317 I4fl4 12K 971 516 231 52 7283 500 m 1218 1361 1151 1045 615 351 148 7535 Teon... Chattanooga........A Knoxville.. ........A Memphis.............. A Memphis...............C Nashville............. A 47.8 46.8 50.0 51.1 0 0 24 c C 33 ( i; 17 c c 13 0 0 22 169 477 Vio 735 58S 467 179 45 171 4J# 744 ? ft* 50( 196 12t 432 671 721 57< 421 13! 24 Ut 392 631 71ft *7< 422 131 2C 154 471 Tib 778 636 438 186 43 0 3384 ( 3590 ( 3137 l 3006 0 3513 Texas... Abilene.................A Amarillo............... A Austin.............-...A Brownsville........ A Corpus Christ!.. .A Dallas................A Del Rio.............. A E3 Paso............. A Fort Worth........ A Fort Worth Amon Carter Fid........ .0 0 l ft tc Lt 0.0 5 37 0 0 0 00 c. o lc uo 0 0 0 0 000 98 350 595 673 479 344 113 0 241 KM 921 711 58f 29$ 91 31 H 402 4* 322 211 50 0 l 51 15S 21! lOf 74 ( ( 0 113 252 330 192 118 6 0 53 299 518 607 A3? 288 75 2ft IS? 371 41! 235 147 21 7( 39( 62f 67t 445 330 no 58 29! 53c 622 446 308 90 0 t c 5 57 299 524 619 432 32ft 81 0 0 2657 ( 4345 ( 1713 ( 617 0 1011 ft 2272 ( 1407 c 2641 c 2361 0 2338 Galveston............. A 000 Galveston.............C Houston............... A ft61.7 60.1 u00 00 Houston............... C Palestine.............. C Port Arthur......... A 61.0 fftt57.1 cc0 00 00 Port Arthur......... C 61.2 0 0 0 Ban Antonio........A ft 0 0 Taylor............. ....... 01/02-40/41 40 .0 0 2 0 13? 286 362 249 176 .28 0 0 1233 C 131 771 356 247 17$ 3G c c 1211 7 181 321 39* 265 184 36 0 1388 0 162 303 m 24C iee 77 (I o 1278 45 260 440 531 m 285 71 c c 1980 2f 218 340 4W 274 211 39 0 ft 1517 8 17(1 316 381 . 25S 181 27 c c 1840 25 201 374 46? 293 19(1 34 0 0 1679 56 234 462 494 375 214 04. 8 oi 1909 Utah... Modena................... 00/01-45/46 4ft Salt Lake City.. .A Salt Lake City.. .C 3ft .3 38.3 40.0 ft ll 156 0 0 88 0 0 61 499 832 1142 1190 944 816 567 338 97 6598 381 rn 1039 1191 88ft 741 453 233 81 5866 330 714 995 1119 857 701 414 208 64 5463 Vt......... Burlington........... A 19 47 172 521 858 1308 1460 1313 1107 681 307 72 7865 Va........ Northfield............... Cape Henry......... C Lynchburg......... .A Norfolk................. A Norfolk................. C Richmond............ A Richmond.............C Wytbeville.......... 98/99-42/43 02/03-40/41 45 39 62 112 283 49.2 0 0 0 V 0 49 009 49.3 0 0 5 0 0 33 47.0 0 0 31 7 13 82 602 947 1389 1524 1384 1176 754 405 166 8804 120 366 648 698 636 612 267 . 60 0 3307 236 531 809 846 722 684 289 82 5 4153 152 m m 729 644 50U 265 59 0 3454 n* 354 636 679, 602 464 220 41 0 3119 210 498 791 828 708 550 271 6ft 0 3955 18? 456 750 787 675 52S 254 57 - ft 3720 352 662 916 945 836 677 410 168 35 5103 Estimating fuel Consumption for Space Heating 533 Table 2____ Average Monthly and Yearly Degree Days for Gties in the United States and Canada (Base 6art iCandadea}' State or Provfecv Station Yoon No. of Arg. Sea- Voter My Aog. Sepi. Oe*. Nov. Ok. Jon. fob. Mar. Apr. May ten* Yaorfy To/of tom rap.J Wash.... North Head L.H. Spokane--------... A Yakima................A W. Va.. Parkersburg........ C 46.4 46.3 45.1 239 m 234 49 45 134 75 70 192 17 23 205 44.9 45.4 66 62 177 295 *288 315 0 0 93 0 7 150 39.4 42.9 9 31 122 0 0 56 341 486 636 704 685 598 492 406 285 5211 329 .540 679 753 602 558 396 246 107 4438 412 633 781 862 678 636 477 307 155 5275 508 879 1113 1243 988 834 561 330 146 6852 375 579 719 797 636 595 435 282 143 4866 405 528 641: 713 610 62!) 525 437 330 5724 m 675 89C 1023 748 56* m 171 38 4848 446 807 1066 1181 862 660 408 2U5 53 5845 412 726 995 1017 910 797 477 224 53 5773 272 600 896 9*9 826 672 347 119 13 4750 Wis....... Wausau................... 15/1&-40/41 26 Yellowstone Park.. 04/05-40/41 37 29.8 30.5 31.4 29.0 33.4 32 58 183 U 2ft 162 13 31 IftO 10 an 137 20 32 134 H 24 112 26 58 216 33 39 241 7 23 244 125 173 424 615 945 1392 1516 1336 1132 696 347 107 8259 447 921 1380 1528 1280 1035 552 250 V4 7650 450 891 1302 1423 van 1008 679 272 . 82 7417 419 864 1287 1417 van 1011 673 266 79 7300 428 831 1218 1336 1142 983 m 351 109 7205 397 79b 1184 1302 1117 961 606 335 100 6944 568 982 1427 1594 1381 1147 680 315 100 8494 577 897 1125 1225 1044 1029 717 462 173 7562 632 10.VJ 1383 1494 1179 1045 687 39ft 163 8303 759 1U79 1386 1464 1252 1165 841 603 334 9605 Medicine Hat....... -. 1921-50 1921-50 1921-50 1921-50 vu Victoria..................... 1921-50 1921-50 1921-45 1921-60 ' 1921-50 1926-60 Winnipeg.................. 1921-50 Saint John................ 1921-50 1939-50 1921-50 St. John'i................. 1933-50 1937-50 1941-51 -'1926-50 Fort Norman........... Yarmouth................. 1921-50 1921-50 1921-50 mv-si 1921-50 1921-50 1921-50 Toronto..................... 1921-50 P.EX. Charlottetown....... 1921-60 Que. Sherbrooke............. 1931-50 1921-50 1921-50 1921-50 1921-50 1921-50 Swift Current........ 1921-60 Y. T... Dawson................... 1921-50 30 30 30 30 30 30. 25 30 30 25 30 3Q 12 30 18 14 10 19 25 25 30 30 30 30 21 30 30 30 30 30 30 20 30 30 30 30 30 '30 30 30 110 170 410 . 90 180 440 6ft 100 350 20 50 300 710 1110 14S3 1530 1350 12Q0 750 1220 1660 178ft 1520 1290 620 1030 1330 1450 1290 1120 600 1070 1440 1590 1380 1130 770 460 270 9520 76C 410 22C 10320 690 400 210 8650 620 320 130 8650 180 220 440 27C 240 340 60 6ft 200 160 I5ftl 23Q 730 1100 1450 1560 1290 1070 10 68(i 860 910 8ii 790 410 620 790 K.VI 711] fx% 410 600 730 800 660 620 730 470 280 5QG 350 46( 290 134. 470 350 230 9500 6910 5230 5410 60 100 350 730 1290 1810 2010 1730 1440 820 420 170 10930 310 370 650 1110 1750 2300 2520 7m 2150 1591 HOC 69C 16810 .40 70 300 690 1250 vno 2000 1710 1440 820 400 150 10630 60 7ft 250 4(1 80 240 110 110 250 600 940 141ft 1570 1410 U8Q 7) 420 150 8830 580 m 1340 1510 1340 1181! 83( 46(i 211 8700 530 830 1250 1400 1270 1100 780 500 250 8380 90 140 320 11 160 320 iso 22C 440 170 160 32U 640 890 1230 1410 1360 1240 900 640 350 9210 66C VA 1231 1431 1321 1211 911 ftbt 381 9440 R4f YXH 1741 21121. 1711 1531 lilt TIC 4U 12140 580 820 1100\ 1270 1230 1160 910 680 380 8780 280 460 800 1400 2040 2500 2580 2310 2280 1690 1050 480 17800 170 350 700 1220 1940 2460 2550 2190 2040 1390 730 280 16020 50 70 180 6f 8C m 111) 120 m 470 740 1120 1260 1180 IftV) 76C 480 210 7510 51( 78T 1131 13M 1281 lift 851 37( 270 8220 430 TJti 1040 1180 1100 1010 750 510 270 7520 90 120 350 M 11 120 IK 174 410 9 4f. 160 2( 40 150 :* 6< 210 2U 3U 140 m 1140 1590 1780 1550 136(1 890 550 240 10350 431 76( n;y 1271 1001 6`A 321 61 6890 781 127( 17W 2061 1771 1571 m 60C 24< 11790 MX 82L 12SA 1421 1291 1111 710 38( 101 7810 49( 841 1201 1321 121C 1041 650 33( 91 7380 S9( m 1481 1641 1481 1231 730 34( 8830 460 V7(] 1130 1260 1160 1020 640 320 70 7020 40 60 200 510 820 1230 1430 1340 use 840 510 220 8380 60 11C 330 11 41 180 2 7i 250 2L K 240 69C noo 1670 I8S0 1660 1410 631 m um 1641 137( 1151 61 99 1471 164< 1461 125< 591 921 1401 1561 1410 1190 88 480 170 10440 700H 301 5i 8130 810 401 IOC 9070 79-K 370 90 8610 7f 141 410 7i IK 370 6 IV 380 5C 9C 340 781 1351 187C 206C 175C 150C 75 129 1741 1941 im 1421 76i 132 1791 1991 17U 1441 68L 1174 1557 1711 1490 im 850 440 210 11430 790 421 191 10770 80 42( 181 10960 730} 400 190 9660 17C 32C GG0 1171 189C 241C 251C 2160 1830 HOO 570 250 15040 534 CHAPTER 37 1959 Guide. appropriately. When data on degree days are available these may be used in the calculation of average outdoor tempera ture for use in Equation 2 or 3. (See definition of.degree day* Chapter 4.) . It may be noted that a portion of Equation 3, (t -- t)Af will, when divided by 24, correspond, exactly to the degree days for the period, provided that t = 65 F, the usual basis for calculating degree days (see discussion of degree days in following sections). Some engineers substitute, degree days for the period, multiplied by 24, for the value of (t -- t*)N in Equation 3: Since this amounts to the basis for degree-day calculations, assuming that t = 65 F, some allowance is thus made for the fact that F will frequently be overestimated, when H is taken as the maximum, or design, heat load. Several time-saving procedures have been devised for quickly estimating the hourly Btu loss of one- and two-story residences in order that fuel estimates can be predicted more quickly from Equation 1. A graphical method of calculating heat losses has been developed" which makes possible a quick solution if the gross waU, ceiling, or floor areas and re spective transmission coefficients are known. The Federal Housing Administration has originated a short-cut formula for residential heat loss determinations which makes use of the floor area and three selected trans mission coefficients. The formula was developed to apply to detached houses approximately rectangular in shape with total exterior door and window areas equal to about 25 per cent of the floor area, and with a floor area not greater than Example l; A residence building is to be heated to 70 F from 6 am. to io pjn. and 65 F from 10 pjn. to 6 am. The calculated hourly heat lorn is 120,000 Btu per hour based on 70 F inside at --10 F outdoors. If the building is to be heated by metered steam, how many pounds would be required during an average heating season? - Solution.- The heating value of steam may be taken as 1000 Btu per lb, and since it is purchased steam, the efficiency can be assumed as 100 percent. Assume average outdoor tempera ture as 36.4 F. The average inside temperature is: <1 X 70) + (8 X 65) _____ ~ 685F. about 1500 sq ft. Equation 4 is for a one-story residence, and Equation 5 is intended for two-story structures. ' Hi = A(G + l/. + t/e + H,)(ti - i.) (4) Ht = A(G + 13U* + 0.5U. + 0.5U/)(U - t.) where . (5) Hi ** heat loss from one-story residence, Btu per hour, ss heat loss from two-etory residence, Btu per hour. A * floor area, square feet, measured to the inside faces of enclosing walls and is the sum of the following areas: Substituting in Equation 1 F 120,000(683 - 36.4)5088 1.00170 - (-10)11000 243,000 lb. Example t: What would be the fuel cost to heat the building in Example 1 during an average heating season, using stokerfired bituminous coal at $14X0 per ton having a calorific value of 13X00 Btu per lb, asuming that the seasonal efficiency of the system is 65 percent? Solution; Substituting in Equation 1 . (1) all the area on each principal floor level; (2) the area of all finished habitable attic rooms, including bathrooms, toilet compartments, closets, and halls; (3) all other areas intended to be heated and not lo cated in the basement. . G glass and infiltration factor for ordinary construction: (0.45 for no weatherstripping or storm windows), (0.40 for weatherstripping), (030 for storm windows with or without weatherstripping). . Um -- coefficient of transmission for outside wall. . 120X00(683 - 36.4)5088 ' 0.65(70 - (-10)113,000 - 28300 lb. U, coefficient of transmission /or ceiling. Uf * coefficient of transmission tor floor. The fuel cost is then (28300 + 2000) (14) = $20100 Example 8: What will be the estimated fuel cost per year of heating a building with gas, agatmmg that the calculated hourly heat los is 92,000 Btu based on 0 F, which includes 26,000 Btu for infiltration? The design temperatures are 0 F and 72 F. The normal healing season is 210 days; and the average outdoor temperature during the heating season is 36.4 F. The seasonal efficiency will be 80 percent. The heating plant will be thermo statically controlled, and a temperature of 65 F will be main tained from 11 pm. to 7 am. Assume that the price of gas is 7.5 cents per 100300 Btu of fuel consumption, and disregard the loss of heat through open windows and doors. - Solution; The average hourly temperature is - . (72 X 16) + (65 X 8) <---------- --^------------------- 69.7 F. Li indoor design temperature, Fahrenheit degrees. t. ** outdoor design temperature, Fahrenheit degrees. . Notes for application of Equations 4 and 6. 1. The calculation of heat loss from heated spaces into ad jacent spaces such as attics, basementless areas, and heated or unheated garages shell be based on the assumption that the temperature of such adjacent spaces is the same as the out door design temperature. . 2. For all floors over basements or other warmed spaces as sume Vr ~ 0. 3. For structures having concrete slab floors laid on the ground a modified application of the formula may be made. Assume Ur -- 0 and calculate the heat loss in accordance with the check formula. Then add the slab loss determined in accordance -with the procedure developed by the National Bureau of Standards and described in Building Materials and Standards Report 103. The maximum hourly heat loss is E = 92300 Btu. The seasonal best loss is 4. No basement area is to be included in the formula calcula tion. If finished habitable rooms in the basement are to be heated, the additional heat loss should be calculated separately and added to the amount obtained by the formula. 92,000(69.7 - 36.4) X 24 X 210 100,000 X 030 X (72 - 0) Both the graphical method" and FHA formulas, when used within the limitations established, have been found to give reasonably accurate results for the average residence, * 2697 hundred thousand Btu. The estimated seasonal fuel cost will be 2697 X $0375 = $20230 but if precise estimates are required, the beat loss should be calculated as outlined in Chapter 12. In the case of gravity warm air heating installations, the load was formerly expressed in square inches of leader pipe It shonld.be, notoj thiit savings (tom night setback may not "1TMaU!d- BooTM temperature may not decrease snd combustion efficiency may be poor during morning pickup.** which can be converted into Btu per hour by multiplying the square inches of leader area by 111,167, and 200 for first, second, and third floors, respectively. Estimating Fuel Consumption for Space Heating 535 DEGREE-DAY METHOD operating efficiencies with the outdoor temperature variable This method is based on consumption data which have fwn tAtfpn from buildings in operation, and the results have been computed on a degree-day basis. While this method may not be as theoretically precise as the Calculated Heat eliminated. Such, results should be used with some reservation since it is possible to have wide variations, for example, as between early and late winter periods.** j/ra Method, it is considered by many to be of more value Computation and Application . for practical use. The amount of heat required in a building depends upon the outdoor temperature, if other variables are eliminated. The general equation for calculating the probable fuel con sumption by the degree-day method is: Theoretically it is proportional to the difference between tiie outdoor and indoor temperatures. The American Gas As- sociation** determined from records in the heating of resi where ' P^UXNXDXC, - <6) dences that the gss consumption varied directly as the de gree days, or as the difference between 65 F and the mean outdoor temperature. In other words, on a day when the mean temperature was 20 deg below 65 F, twice as much gas was consumed as on a day when the temperature was 10 deg below 65 F. For any one day, when the mean tempera ture is less tha.n 65 F, there are as many degree days as there are degrees difference in temperature between the mean temperature for the day and 65 F. Degree days may be cal F -- fuel consumption for the estimate period. U unit fuel consumption, or quantity of fuel used per (degree day) (building load unit). N -- number of butldinp load units (when available, use calculated hourly heat loss instead of actual amount of radiation installed). - D > number of degree days for the estimate period. Cf ~ temperature-correction factor from Table 3. culated on other than the 65 F base for use mainly for ware house and other industrial spaces in which temperatures to be maintained are considerably below the 68 to 72 F range. ' Table 3 .... Correction Factors for Outdoor Design Temperatures* They are listed in a later section of this chapter. Studies made by the National District Heating Associa Outdoor OodQO Temp f. .. -20 -10 0 +10 +20 tion1* of the metered steam consumption of 163 buildings located in 22 different cities, and' served with steam from a Correction factor......... 0.778 0.875 1.000 1.167 1.400 district heating company, substantiate the approximate cor rectness of the 65 F base chosen by the gas industry. Table 2 lists the average number of degree days that have occurred over a long period of years, by months, and the yearly totals for various cities in the United States and Canada. The number of degree days for United States cities were calculated by taking the difference between 65 F and the daily mean temperature computed as half the total-of * The mainpliers in Ts&le J, which m high tar mild efimsfra end low tor eotd rogiMa, an inerror u might appear. The emit figure* in Tabfca 4, S, and are per aqu&ro foot <4 radiator or thousand Btu beat loro per degree day. For equiva- L-ntixiiMinp--J hrr18"f worm ihrr i~ --Tm r11Trntrt h*~l'~T-l*Tlr *T~* load usd "mH" radiator quantitiee than thoee in cold cities. Consequently, the tuttl figure in quantity of tael per (square (ootof radiator) (degree day).* targes for warm localities than for colder regions. Sian the northern atisa hare more radiator surface per given budding and 0 higher seasonal degree-day total than cities in the south, the total fml per isnnn will be larger for the northern dty- the daily maximum and the daily minimum temperatures. The monthly averages were obtained by adding daily degree days for each month each year and dividing by the number of days in the month; then totaling the respective calendar monthly averages for the number of years indicated and di viding by the number of years. The total or long term yearly average degree-day value is the summation of the 12 monthly averages. Degree days for Canadian cities were supplied by the Canadian Meteorological Division of the Department of Transport, and were computed from the mean temperature Vahies of N depend on the particular building for which the estimate is being prepared and must be found by survey ing plans, by observation, or by measurement of the build ing. Values of U for use in this equation are the unit fuel consumptions per degree day, obtained as a result of the col lection of operating information and listed in Tables 4, 5, and 6. Attention is directed to the nature of there units in the next following sections. normals on record for the various stations. (See Note c, Table Unit Fuel Consumptions per Degree Day 2.) ... . Any attempt to apply the degree-day method of estimating The quantity of fuel used per degree day in a given heat fuel consumption for less than one month would be of very ing plant be reduced to a unit bn.ris in terms of quantity little value. It should be noted that this method of calcula of fuel or steam per degree day per thousand Btu hourly tion is based on a long term average and cannot be expected _ heat loss-at design conditions. A less frequently used basis is to coincide with any single year in calculating fuel require quantity of fuel per (degree day) (square foot of floor area). ment. Individual yearly degree-day. calculations may vary In fact any convenient unit can be used to relate the con as much as 20 percent above and below the long term aver sumption to the degree day and to the building. The choice of these units requires explanation, and some age. discrimination and judgment. If the volume baas is used, If the degree days occurring each day are totaled for a rea the net heated space is preferable to the gross building cub sonably long period, the fuel consumption during that period age, since gross cubage includes outer walls and certain por as compared with another period may be assumed to be in tions of attic and basement space that are usually unheated. direct proportion to the number of degree days in the two In the absence of data on net heated volume, a value of 80 periods. Consequently, for a given installation, the fuel con percent of the gross'volume may be used to obtain the esti sumption can be calculated in terms of fuel used per degree mated net heated volume. The volume basis has been rather day for any sufficiently long period, and compared with widely used primarily because it is simple to apply. In in similar ratios for other periods to determine the relative dustrial buildings it is usually easier to obtain the correct 536 CHAPTER 37 . 1959 Guide Table A .... Unit Fuel .Consumption Constants (U) for Gas* Bated oe 0 F Outdoor Temperature, 70 F Indoor Temperature . . Hot Water Steam Worn Air Heating Vatom of Gat Btu per Co Ft Cu Ft Gat per Degree Day per Sq Ft EDS Cu Ft Co* per Decree Day pet Sq Ft EDR Co Ft Goa per Degree Day per 1000 Btu Hourly Design Heat Loss Up to 500 Sq Ft 500 to 1200 Sq Ft Over 1200 Sq Ft Up to 300 SqFt 300 to 700 Sq Ft Over 700 Sq Ft Gro.it, Fan Systems 500 535 800 ' 1000 0.149 0.139 ' 0.094 0.075 0.142 0.132 0.087 0.071 0.134 0.126 0.085 0.068 0.254 0.237 0.159 0.127 0.242 0.226 0.151 0.121 0.231 0.216 0.144 0.116 0.896 0.840 0.560 0.449 0.861 0.805 0.538 0.431 Gas Consumption in Therms per Degree Day ' 1 Therm * 100,000 Btu 0.000743 0.000709 0.000675 0.00127 0.00121 0.00116 0.00450 4 Abstracted from Comfort HtaUnf, American Cm Amoastioo, 1938, And 5 percent added for operation without nicht reduction of temperature. 0.00430 " volume of a given building than to measure and evaluate the heating capacity of its heating system, or calculate its maxi mum hourly Btu loss. The comparison of buildings on a straight volume basis does not allow for variation in expo sure, type of construction, ratio of exposed area to cubical contents, and type of occupancy. It is inaccurate for estimat ing purposes unless the buildings are of very similar nature. The calculated heat loss or the heating capacity of the in ' stalled radiation may be used as the unit. The use of the heat ing capacity of the installed radiation is of questionable value when referring to heat-transfer surfaces used in warm air furnace or central air-conditioning systems. Where steam or hot water radiation is already installed, care should be exercised when using the installed radiation as the basis for estimating, since actual installed radiation may differ con siderably from the exact radiation requirements. In view of all these considerations, it is believed that the unit based on thousands of Btu of hourly calculated heat loss for the design hour is probably the most desirable. Estimating Gas Consumption Values of the Unit Fuel Consumption Constant U for gas , are given in Table 4 for various gas heating values, and dif ferent types and sizes of heating systems. They are based on an indoor design temperature of 70 F and an outdoor design temperature of 0 F, and apply only to these conditions. For other outdoor design conditions corrections must be made by applying factors given in Table 3. . The factors in Table 4, as corrected if necessary, are satis factory for regions having 3500 to 6500 degree days per heat ing season. In regions with less than 3500 degree days the unit gas consumption is higher than given; where over 6500, the unit is less than given. Ten percent addition or deduction in these cases is recommended by A.GA. publications. This table cannot be used for making estimates for industrial buildings where low inside temperatures are maintained. For gas heat values other than those given in Table. 4, simply interpolate or extrapolate. It will also be noted that Table 4 applies only to small installations. Since the unit gas consumption becomes smaller as the installation becomes larger, the values in the table should be used with care, if at all, for large gas-burning installations. Example 4' Estimate the gas required to heat a building located in Chicago, 111., where the heating season has 6310 de- ~ gree days and the gas heating value is 800 Btu per cu ft. The calculated heating requirements are 1000 sq ft of hot water radiation based on design temperature of --10 F and 70 F. Solution: From Table 4, the fuel consumption for a design temperature of 0 F with 800 Btu gas is founa to be 0.087 cu ft of gas per (degree day) (square foot of hot water radiation). Table 5 .... Unit Fuel Consumption4 ' Constants (U) for Oilb Bajed oa 0 F Outdde Temperature, 70 F Inode Temperature Unir . Efficiency in Percent 70 80 Gal oil per sq ft hot water radiator.... 0.00066 0.08437 0.00092 0.00058 0.00383 4 Baaed oa a Vating value of 141,000 Btu pa (mllou. b Abstracted by penntesioo tram Doerto-Dat Handbook (Second Edition, 1937), by C. Strock aad C. H. B. HotchVww, Sevas percent added for operation without sight reduction of temperature aad'chmnge to Btu per gallTM. value of 141,000 Per degree day. Table 6 .... Unit Fuel Consumption4 Constants (l/) for Coal* Based on 0 F Outdoor Temperature, 70 F (Aside Temperature ' IMP Efficiency in Percent 40 50 60 70 80 Lb coal per sq ft steam radiator........................... Lb coal per sq ft hot water radiator............ Lb coal per 1000 Btub neat loss............ 0.0216 0.0172 0.0143 0.0123 0.0108 0.0135 0.0108 0.0091 0.0078 0.0068 0.0889 0.0717 0.0592 0.0507 0.0444 4 Baaed os a beating value of 12,000 Btu per pound. - b Abstracted by permiaaioo from Defrso-Day Handbook (Second Edition, 1937), by C. Strock and C. H. B. Hotchkis. Eight percent added for opeiatioo witbont night reduction of temperature. * Far degree day. Estimating Fuel Consumption for Space Heating 537 ' is 6047, so sumption is during these three months the estimated con . F = 0.076 X 1000 X 6310 = 480,000 cu ft. Estimating Oil Consumption Table 5 gives unit fuel consumption factors for oil, similar to those given for gas in Table 4. . The factors in Table 5 apply only to an indoor design tem perature of .70 F and an outdoor design temperature of 0 F. For other outdoor design temperatures, the constants in Table 5 must be multiplied by the values in Table 3 as ex plained under Estimating Gas Consumption. Values given in Table 5 are based on use of oil with a heat ing value of 141,000 Btu per gallon. For other heating values, multiply the values in Table 5 by the ratio of 141,000 divided by the heating value per gallon of fuel being used. Example 6: Estimate the seasonal oil consumption of a boiler, designed for-oil firing, in a building located in Toledo, Ohio Thebuiiding has a calculated heat loss ot 240,000 Btu per hr. The oil heat value is 144,000 Btu per gal, and the as sumed seasonal efficiency is 80 percent. The outdoor design tem perature for Toledo is --10 F, and the indoor design temperature is 70 F. Solution; From Table 5, under .80 percent efficiency and in the bottom line, the value of U is found to be 000383 gal per 1000 Btu hourly heat loss for 0 F outdoor temperature. The correction factor for --10 F outdoor design temperature from Table 3 is 0875 which TM*kns the correction 0875 X 000383 -- 080335. Making a further correction for the heating value, 080335 X (141,000/144,000) -- 0.00328 gal per 1000 Btu per hr calculated heat loss per degree day. From Table 2, the total normal degree days'lor Toledo are 6394. Since U is expressed in 1000 Btu, N is equal to 240. Sub stituting in Equation 4 F = 080328 X 6394 X 240 = 5030 gal. Estimating Coal or Coke Consumption Coal or coke consumption estimates are made by following exactly the same procedure as for-oil. Values of 0 are given in Table 6 which only apply to an indoor design temperature of 70 F and an outdoor design temperature of 0 F. A correc tion must be made for other conditions by use of the mul tiplying factors in Table 3. Data in Table 6 are based on 12,000 Btu per lb coal, and for'other heating values of cod they must be multiplied by the ratio of 12,000 divided by the heating value of fuel used. ' Example 6: A building in Scranton^ Pa. has a calculated heat loa of 240,000 Btu per hr based on an indoor design temperature of 70 F and an outdoor detig" temperature of --10 F. What will be the estimated normal seasonal anthracite or coke consump tion for hoaxing if 13,000 Btu per lb fuel is burned in a hand- fired boiler, with automatic control, at a seasonal efficiency of 80 percent, and what part of the total will be used during November, December, and January? '- Solution: From Table 6, U is 08444 of coal or coke per 1000 Btu per hr heat loss per degree day. Correcting for the out door design temperature of --10 F from Table 3, the value of U is 0875 X 08444 = 083S9. From Table 2, D is 6218 and from the problem, N is 240. Substituting in Equation 4, F = 08389 X 240 X 6047 = 56,500 lb. Fuel used over any period is, according to the theory of tiie degree day, proportional to the number of degree days during the period. From Table 2, the average numbers of degree days for November, December, and January is Scranton are 693, 1057, and 1141 respectively, a total of 2891. The yearly total ^ X 56,500 = 27,000 lb. Estimating Steam Consumption In estimating steam consumption the efficiency is generally assumed at 100 percent. If for low-pressure steam an average hpftting value of 1000 Btu per pound of steam is used, no correction is necessary. In comparing values from different cities, correction should be made for design temperature .(see Table 3) when the unit figures are in terms of heat los but not when the values are in terms of building volume or floor space. Where the heat loss is calculated in Btu per (hour) (de-. gree difference in temperature) the simple Equation 7 may be used: '. B X 24 X D 1000 (7) P -- pounds of steam required for estimate periodB - calculated heat loss, Btu per (hour) (degree differ ence). 24 = hours in one day. D *=> number of degree days for the^period of estimation. - 1000 *= Btu delivered per pound of steam condensed. . In this method the number of degree days automatically t-akea care of average indoor and outdoor temperature dif ference. When degree days are taken from Table 2, an av- Toble 7____ Steam Consumption of Buildings with Various Types of Occupancy* Type of BuBding No. Bldg* Average Volume Heated Space 1000 C*F# Steam far Heating Lb per DD per 1000 Cu Ft of Occu pancy Office and Printing.......................... Office and Stores or Shops.......... 334 49 8 7 26 Department Store............................ Loft........................................................... Warehouse...-....................................... 16 63 73 63 24 Hotel and Club.................................. Manufacturing.................................... 73 61 22 13 19 Municipal or Federal...................... Lodge, Gym, Hall, or Audito- Miscellaneous........................ ............. 9 4 8 15 12 7 2160 3000 1895 4950 1615 806 3400 310 865 2230 1795 1425 1240 1540 1350 656 3306 1115 3215 880 1387 0.685 0.577 1.230 0.412 0.617 12.1 13.1 17.7 12.9 13.2 0.786 0.385 0.624 0.588 0.459 11.7 11.1 10.4 10.0 9.4 0.990 0.962 0.482 0.202 0.808 22.3 21.8 12.9 21.4 9.5 0.532 1.194 0.592 0.587 7.9 22.0 11.5 15.6 0.390 12.4 0.479 21.4 4 Principle* oj Economical Htatine, National Association of Building Owner* uriA Uanacern. 538 CHAPTER 37 1959 Guide Table 8 .... Degree Day* for Industrial Heating in Various Cities of the United States* Annaf Total* for o Normal Heeling Seaton 0*8'- H State cur State 55F Rom Sow OegpM Oayt. Qfy State 4SF S5F Rate Bom OwgrM Dor* Gfy 45F S5F Roa* Ala.... a- Montgomery........... Aris... Axk.... Cal... San Francisco..... San Luis Obispo... Col... Pueblo..................... Conn.. D.C .. ,, Fla.... . AA*u1au.ia.................. Qwa.^'tnMnilnUnUl.I Idaho.. D T *1 faim 276 519 1757 1499 1769 1041 1045 1034 2161 1969 504 229 37 1188 803 384 230 3440 3433 3261 3237 2487 127 231 2814 4140 2119 3743 Md.... Masa . 1787 1514 Mich. . p. 1. . T7* ' n.' a n vv Grand Rapids........ 3131 2332 lljC na**1j*"1.L^11 U**............. Sault Ste. Marie 4049 Minn.. 4419 3309 4796 St. Taul................... Miss... Mo___ Columbia................. k*m(w City........... Springfield.............. 1252 1635 1463 1186 982 Havre....................... 3736 2843 Kalispell.................. 2874 Neb... 3023 2291 2284 2833 Nev. .. 1670 2646 2491 3603 3419 5499 4177 6575 6774 5417 6572 468 3231 2980 2745 2423 5874 5071 5131 4152 3982 4801 3468 4640 1487 3147 1949 3425 1990 3757 Okla... Oklahoma City. 600 1835 2321 4307 Portland................. 373 1911 272 1868 Pa....... Erie.......................... Harrisburg.............. Philadelphia......... Pittsburgh.............. 2337 1565 1122 1938 1377 3837 3236 2695 3755 3028 R. I. .. 871 3388 Charleston............. 759 Greenville....... ....... 297 1502 S.D.... Huron...................... 3743 Pierre...................... 3162 2590 5678 5234 4628 6045 Tenn, . 431 1741 166 1284 419 1678 Tex... San Antonio........... 915 786 2220 32 919 754 43 110 484 305 Utah.. 1978 3981 Salt Lake City.... 1475 3202 Ind__ r j' iio Kan... Ky... Iaju ill1 New Orleans......... Me... - 799 1397 3370 2296 2440 2335 4180 N. J... N.M.. N. Y... 1926 4732 1123 1634 2359 2412 1652 1385 1152 2956 2530 1811 2557 2294 30 565 4572 2341 N.C.. 172 229 Wilmington............. N.D... 4616 Ohio. 1376 1600 2904 3106 Va.... 4316 4023 Wash. 4231 1388 718 W. Va 729 Wis... 6399 3003 Wyo.. 3255 Norfolk................. Walla Walla......... 3014 4984 3652 7121 554 1928 260 1496 549 1895 184 408 1741 507 993 2062 2185 3872 2365 2565 1506 3327 1147 2784 3318 3034 3067 2657 5331 3992 4850 4617 2500 4700 3208 5450 Prom DcfrweOsir Bon&eok, by C. Steoek 8&dC. H. B- Hotehkmg (Tbs Indutteiml Prem, tf37. pp. US-1M). VUue* are not coordinated with Table J which is from a later eouzea. Estimating Fuel Consumption for Space Heating 539 erage indoor temperature of approximately 70 F is assumed throughout the period. If an average indoor temperature other than approximately 70 F is to be used, the number of degree days should be obtained for the new base. Example 7; An eight-story building in Pittsburgh is operated with a daytime temperature of 70 F. The calculated heat loss is 10,500 Btu per (hr) (degree temperature difference). What is the estimated average yearly steam consumption for building heating? Solution: Since the average indoor temperature is approxi mately 70 F, the degree days from Table 2, based on 70 F may be used. Therefore, from Table 2, Pittsburgh has 5048 degree days per normal season. Inserting in Equation 5: 10,500 X 24 X 5048 1,272,000 lb of steam. 1000 Consideration has been given to the difference in steam utilization of different types of buildings, and Table 7 shows actual average units for these various types. These figures were obtained from operating results in 896 buildings located in all sections of the United States. Being averages, and for small groups in each type, the figures may need tonsderabie modification to allow for local variations. It should be especially noted that the steam used for healing water for service is not included in the values given in Table 7. Additional figures are to be found in a paper presented before the Society " Example 8: A store in Philadelphia with a heating system designed to maintain 70 F indoors in 0 F weather has 250,000 cu ft of heated space. What would be the estimated average yearly steam consumption of purchased steam for heating? Solution; According to Table 7, a store would use 0.624 lb of steam per degree day per 1000 cu ft heated space. From Table 2, Philadelphia has 4523 degree days per normal year. Inserting in Equation 4: F = 0.624 X 250 X 4523 - 706,000 lb of steam. Degree Day as an Operating Unit The degree day is also widely used as a means of com paring the efficiency of the fuel consumption of one period with another for the tame building. Since the fuel consump tion is approximately proportional to the weather (degree days), and since the periods to be compared may not have the same weather conditions, the comparison can be rnwdA only after the fuel consumptions have been computed on . a comparable weather basis, that is, upon the actual number of degree days occurring for a given month and year in the . city under consideration. Since fuel consumption is propor tional to the number of degree' days, plant operators fre quently compute each month the fuel burned per degree day by the heating plant. The resulting unit value, by eliminating the outdoor temperature variable, indicates whether the operating efficiency of the plant is above or below the pre vious month or year. INDUSTRIAL DEGREE DAYS When estimating the heating requirements of warehouses, factories, and other building where the indoor temperature to be maintained differs greatly from the usual indoor tem perature range of 68 to 72 F, it is common to use degree days based on temperatures of 55 to 45 F. These are gen erally referred to as industrial degree days, and are listed in Table 8 for a number of cities using both 55 F and 45 F as the base. In general, the degree days (55 F base) are used when the temperature of the heated space is to be main tained at approximately 60 F. For an inside temperature of about 50 F, the degree days calculated on a 45 F base should be used. The industrial degree days are useful for estimating fuel consumption by comparison between localities in which difference in degree days is not too great, and where known fuel consumption of one building may be used determine unit consumption per degree day. MAXIMUM DEMANDS AND LOAD FACTORS In one form of district heating rates, a portion of the charge is based upon the marimnm demand of the building. The maximum demand may be measured in several dif ferent ways. It may be taken as the instantaneous peak or as the rate of use during any specified interval. One method is to take the average of the three highest hours during the winter. These figures ar shown for a number of buildings in Detroit in Table 9" Table 9 .... Building Load Factors and Demands of Some Detroit Buildings load Factor lb of Doioaad pot (Hour) (SqFtEDK) Clubs and Lodges...................... Hotels............................................ Printing......................................... Offices............................................. Apartments................................. Retail Stores................................ Auto Sales and Service.............. Banks............................................. Churches....................................... Department Stores..................... Theaters........................................ 0.318 0.316 0.287 0.263 0.255 0.238 0.223 0.203 0.158 0.138 0.126 0.184 0.207 0.217 0.209 0.225 0.182 0.248 0.158 0.152 0.145 0.151 These maximum demands were measured by an attach ment on the condensate meter, and therefore represent the amounts of condensate passed through the meter in the highest hours, rather than the true rate at which steam is supplied. There might be slight differences in -these two quantities due to time lag and to storage of condensate in the system, but wherever this has been investigated it has been found to be negligible. The load factor of a building is the ratio of the average load to the maximum load and is an index of the utilization. Thus, in Table 9, the theaters, operating for short hours, have a load factor of 0.126 as compared with the figure of 0-318 for clubs and lodges. REFERENCES . * W. S. Harris and R. J. Martin: Heat transmitted to the I=B=R research home from the chimney (ASHVE Transac tions, Vol. 59, 1953, p. 97). *S. Konxo: The Stoker-fired Worm-car Furnace in the Re search Residence (University of Illinois, Engineering Experi ment Station Circular 39, 1939, p. 98). * Performance of a Hot Water Heating System in the I=B~R Research Home at the University of Ilhnois (University of Illinois, Engineering Experiment Station Bulletin No. 349, January 4, 1944). 4 W. G. Colborne: Performance of intermittently-fired oil furnaces (ASHAE Transactions, Vol. 63, 1957, p. 427). s-f f 540 CHAPTER 37 1959 Guide Comfort Heating (American Gas Association, 1938). W. M. Myler, Jr. and H. W. Nelson: Are automaUc air shutters justified on a gas-fired conversion burnerT (ASnVh, Transactions, Vol. 55, 1949, p. 111). t r w. Tieman and F. L. Bagby: Efficiency of bituminouscoal-buiuing space heater.(ASHVE Transactions, Vol. 57,1951, p. 89). . * R A Sherman and R. C. Cross: Heat losses and efficiencies of fuels in residential beating (ASHVE Transactions, Vol. 43, 1937, p. 185). . Fuels and Burners (University of Illinois, Small Homes Courted Circular G3fi, July 1919). **A P. 'Krats and S. Konso: Investigation of Oil-fired Forced-air Furnace Systems in the Research Residence (Uni versity of Illinois, Engineering Experiment Station Bulletin No. 318, November 7, 1939). u Paul D. Close: Graphical method of calculating heat losses (ASHVE Transactions, Vol. 49, 1943, p. 345). " House Heating (American Gas Association, Industrial Gas Series, 3rd ed.). -. "Report of commercial relations committee (National Dis trict Heating Association Proceedings, 1932). "Rutcher Skagerbere and J. E. Phifer: Fuel ronamiption analysis for multi-family housing projects (ASHVE Transac tions, Vol. 59, 1953, p. 113). "C. W. Signor: Heat requirements of buildings (ASHVE Transactions, Vol. 57; 1951, p. 517). "J H. Walker and G. H. Tuttle: The heat requirements of buildings (ASHVE Transactions, Vol. 41, 1935, p. 171). CHAPTER 38 REFRIGERATION Refrigeration Theory: Definitions and Basic Concepts, Refrigerants, Vapor Compression Refrigeration Cydes, Suction and Discharge Pressure Effect, Complex Refrigeration Cycles, Air Cycle, Steam Jet, Absorption System; Basic Refrigeration Equipment: Compression Machines and Controls, Condensers, Evaporators and Coolers, Refrigeration Control, Piping and Accessories, Equipment Characteristics and Selection ITH the increasing use of all-year comfort air-condi evaporator is then raised in pressure (by a compressor, or by W tioning installations, the importance of refrigeration the absorber-generator combination of the absorption sys to the air-conditioning engineer has been greatly magnifietde.m) until its new boiling temperature exceeds the tempera The details of equipment operation, maintenance, and de ture of the available cooling medium. Under these conditions, sign remain problems for the refrigeration engineer,.but the heat transfer is established from the refrigerant vapor to the air-conditioning engineer does retain a responsibility to the cooling medium with resultant condensation of the refriger customer which requires on his part some knowledge of the ant. When condensed, the high-pressure liquid refrigerant is different refrigeration cycles and the relative merits of each. reduced in pressure and again allowed to boil in the evapo In order to assist in meeting this need, the present chapter rator. . has been divided into four parts-, the first covering the funda- . In order to permit evaluation of the effectiveness with mental technical relationships which govern the selection and which any given cycle operates, some term is desirable that analysis of an operating cycle, the next two presenting brief would be comparable to the term efficiency used for heat en discussions of basic refrigerating equipment and auxiliaries, gines. In. refrigeration the desired effect is heat extraction, and the last, information on selection criteria. . And the cost of achieving this extraction is the amount of REFRIGERATION THEORY energy that must be supplied as shaft work. Thus the ratio of refrigerating effect to the heat equivalent of the compres Definitions and Basic Concepts . sor work is used as a measure of effectiveness, and is defined Vi as the coefficient of performance. . . . If the desired effect is the rejection of heat through the The ton of refrigeration is a quantity unit which'originated ` condenser instead of heat extraction through the evaporator, m the days when harvested ice was the principal source of ' the refrigeration system is then termed a heat pump. In this summer cooling. By definition the ton is the cooling effect case"the coefficient of performance is the ratio of the heat re realized when one ton of 32 F ice melts to water at 32.F. Since. ' jected from the condenser to the heat equivalent of the com the latent heat of fusion of ice is 144 Btu per pound, the ton pressor work. The coefficient of performance for the heat represents a unit cooling effect of 144 X 2,000 = 288,000 Btu. pump is greater -than that for a system operating as a re In common practice the ton is usually considered a rate frigerating machine, because all mechanical shaft work re (rather than quantity) unit, and is taken as 288,000 Btu per quired to operate the compressor is dissipated as useful heat day (24 hours), or 12,000 Btu per hour, or 200 Btu per min - through the condenser. .. ute. Thus for air-conditioning calculations, the size of the The Carnot cycle, an ideal, thermodynamically reversible requisite refrigeration machine, expressed in tons, can be ob cycle consisting of an adiabatic expansion and an isothermal tained by dividing the heat gainof the structure, expressed expansion, followed by an adiabatic compression and an iso in Btu per hour, by 12,000. In equation form: thermal compression to form a closed cycle, may be shown to . Hi *" (Btu per hour heat gun) -s- 12,000 (I) be a measure of the maximum possible, conversion of heat energy into mechanical energy. In its reversed form it is a tcAerc . .. measure of the maximum performance possible for any re H, * load in tons. frigeration cycle operating either as a refrigerator or as a heat pump. Although it cannot be applied in an actual machine The working substance, or refrigerant, is the fluid which because of the impossibility of obtaining complete reversi carries heat through the refrigeration cycle from the evapora bility, it is, nevertheless, extremely valuable as a criterion of tor, where heat enters the refrigerant, to the condenser where inherent limitations. The coefficient of performance (CP) of the heat is discharged to some cooling medium. The great ma a reversed Carnot cycle system operating as a refrigeration jority of modern refrigeration systems use a liquefiable vapor system is . as the working substance. By altering the' pressure of the 'p refrigerant its boiling temperature, is changed, allowing the material to bod in the evaporator at a -temperature suffi ' (CP) T, - T, ciently lower than that of the conditioned space, to insure maintenance of an effective heat transfer rate from the space (or in some cases from a secondary cooling fluid such as brine > evaporator temperature, Fahrenheit, absolute. or cold water) to the refrigerant. The vapor formed in the > condenser temperature, Fahrenheit, absolute.' 542 CHAPTER 38 1959 Guide Temptrofur*--F; Veto*--Co F* par Lb; Entropy--Bto per Ub) If deg). Fig; 1 .... Pressure-Enthalpy Diagram for Diehlorodifluoromethane (COtFi) (Refrigerant 12) Refrigeration 54$ With the ideal C&mot cycle operating as a heat pump, the co efficient of performance is ' (CP> - < The Carnot cycle coefficient of performance for both a re frigerating machine and a heat pump increases as the spread between the evaporator and the condenser temperatures de creases. In genual, the same is true tor an actual system operating as either a refrigerating machine or a heat pump. Refrigerants A desirable refrigerant should possess chemical, physical, and thermodynamic properties that permit its efficient ap plication in refrigerating systems. In addition', when the vol ume of the charge is large, there should be little or no danger to health or to property in case of its escape. Thermodynamically, a material for use as a refrigerant should have a large latent heat of vaporisation since it is this heat quantity--subject to minoT variations--that constitutes the working effectiveness of the refrigerant. Further, ranee the work required to compress a vapor increases rapidly with the pressure ratio, the thermodynamic characteristics of the fluid should be such that the required low-to-high temperature range can be achieved with only a moderate change in ratio. A further consideration, from the standpoint of practical operating effectiveness, is that the suction pressure should not be below atmospheric (to prevent leakage of air into the refrigerant lines) nor should the condenser pressure be ex cessively high (to prevent need for extra-heavy construc tion). The specific volume-specific enthalpy relationship is also important because some materials would have such low density, when in vapor form, that impractical compressor displacements would be needed to handle the suction vapor. Properties of refrigerants are usually given either in tabu lar or graphic form. In contrast to the temperature-entropy, plotting which is used almost exclusively in steam-power work, refrigeration problems are usually referred to a pres sure-enthalpy chart. The advantage of pressure-enthalpy plotting in that linear distances on tiro-chart correspond to. energy gains or losses, and the two types of processes, con stant-pressure and constant-enthalpy, that occur most fre quently in refrigeration cycles, can both be represented by straight vertical or horizontal lines, figs. 1 and 2 present pressure-enthalpy charts for- dichlorodifluoromethane, .CCUF^ and monochlorodifluoromethane, CHCLF,, respec tively. Although tabular arrangements of refrigerant proper ties require interpolation between values, they have the ad vantage of an accuracy greater than that obtainable from a chart. Tables 1, 2, 3, and 4 give the thermodynamic proper ties of four of the more common refrigerants used in air conditioning installations: Refrigerant* 12,dichlorodifiuoromethane; Refrigerant 22, monochlorodifluoromethane*, Refrigerant 11, trichloromonofluoromethane; and Refriger ant 113, trichlorotrifluoroethane. The first two of these are commonly used in reciprocating compressors while the last two are commonly used in centrifugal machines. Referring to Table I, the first column gives the range of saturation temperatures likely to occur in practice. The sec ond column gives the saturation pressure expressed in (rounds Per square inch absolute corresponding to a given tempera ture, while the next six columns give the three fundamental specific properties, volume, enthalpy, and entropy, of the saturated liquid and saturated vapor, respectively. The last * ASBE desxnstioaa (or tbeae refricwmnt*. four columns give values of enthalpy and entropy for gases; with 25 deg and with 50 deg of superheat; note particularly that the column heading 60 F superheat means, not that thegas is at a temperature of 50 F, but that its temperature ex ceeds by 50 deg the saturation temperature corresponding to its actual pressure. Tims, CCUFt vapor at 38.0 psig and 91 F possesses 50 deg of superheat, since its saturation tempera ture corresponding to 52.7 psia is 41 F. The tabular arrangements of refrigerant properties are lit erally for saturated or superheated materials only. In many cases, however, the engineer must work with subcooled liq uids. With an accuracy sufficient for all practical purposes, , the specific volume and the enthalpy of any subcooled refrig erant can be taken as equal to the values read from the tables for a saturated liquid at the game temperature. Thus, if CCUFj at 121 psia and 40 F is passing through a pipe, its volume and enthalpy can be determined from Table 1 as 0.0116 cu ft per pound and 17.0 Btu per pound. Frequently it is necessary to determine the properties of a toet vapor or of a mixture of liquid with some added vapor, such as is found at the discharge from an expansion valve. This can be done from the tables by noting that the specific enthalpy of the mixture must be equal to that of the saturated liquid, plus a fraction of the latent heat of vaporization equal to the fraction of refrigerant that is present in vapor form. -Consider, for example, CC1*F, with a, quality (the percent in vapor form) of 30 percent; the enthalpy of this material would be equal to A. - A, -f 0.30 (A, - A/) . (4) where ' Km " specific enthalpy of the mixture. hf " specific enthalpy of the liquid. . A, -- specific enthalpy of the saturated vapor. Values of A/ and A,,for use in Equation 4 mu be obtained directly or by calculation from the tables of properties of re frigerants. ' By a reversal of this same procedure the tabular data can be used to determine the state of a mixture leaving an ex pansion valve. Consider a valve to which saturated liquid at pressure p, is admitted, and a mixture of saturated liquid and vapor at pressure pd is discharged. The quality of the material at discharge is then determined by making use of the fact that tiro expansion process is completely irreversible, is a throttling process, and hence, occurs without change in enthalpy. Thus, the enthalpy of the mixture. A,,, is equal to the enthalpy of the saturated liquid at the entrance state, Af,, and can therefore be read from the table. Thus, A/, TM hm = Aw -- (1 -- x) (Aw -- hjt) (5) or, * " {hm ~ h/t) *- (Aw -- A/*) (6) where hf, enthalpy of saturated liquid at entrance to expansion valve. . hm " enthalpy of mixture. Aw = enthalpy of saturated vapor at discharge. h/t " enthalpy of liquid at discharge. x * proportion of liquid in the mixture, decimal. Vapor Compression Refrigeration Cycle Simple Cycle. The refrigerant cycle is the series of state changes (which occur in the conditioning processes) needed 544 CHAPTER 38 1959Guide Serf- Tamp. f AlM.rrao.Lb par Sq la. 0 23.87 2 24.89 4 25.96 S 28.51. 6 27.05 Table 1 .... Properties of Dichtorodifluoromethane (CGFt}* VaJw liquid Vapor Enthalpy Liquid Vapor Enthalpy and Entropy foften Fro --40 F Entropy 25 F Superheat Liquid Vapor Enthalpy Entropy 0.0110 0.0110 0.0111 0.0111 0.0111 1.637 1.574 1.514 1.485 1.457 8.25 8.67 : 9.10 9.32 9.53 78.21 78.44 78.67 78.79 78.90 0.01869 0.01961 0.02052 0:02097 0.02143 0.17091 0.17075 0.17060 0.17052 0.17045 81.71 81.94 82.17 82.29 82.41 0.17829 0.17812 0-17795 0.17786 0.17778 50 F Superheat Enthalpy Bitropy 85.26 85.51 85.76 85.89 86.01 0.1S547 0.18529 0.18511 0.18502 0.18494 8 28.18 0.0111 1.403 9.96 79.13 0.02235 0.17030 82.66 0.17763 86.26 0.18477 10 29.35 0.0112 1.351 10.39 79.36 0.02328 0.17015 82.90 0.17747 - 86.51 0.18460 12 30.56 0.0112 1.301 10.82- 79.59 0.02419 0.17001 83.14 0.17733 86.76 0.18444 14 31.80 0.0112 1.253 11.26 79.82 0.02510 0.16987 83.38 0.17720 87.01 0.18429 16 33.08 0.0112 1.207 11.70 80.05 0.02601 0.16974 83.61 0.17706 87.28 0.18413 18 34.40 0.0113 1.163 12.12 80.27 0.02692 0.16961 83.85 0.17693 87.51 0.18397 20 35.75 0.0113 1.121 12.55 80.49 0.02783 0.16949 84.09 0.17679 87.76 0.18382 22 37.15 0.0113 1.081 13.00 80.72 0.02873 0.16938 84.32 0.17666 88.00 0.13369 24 . 38.58 0.0113 1.043 . 13.44 80.95 0.02963 0.16926 84.55 0.17652 88.24 0.18355 28 40.07 0.0114 1.007 13.88 81.17 0.03053 0.16913 84.79 0.17639 88.49 0.18342 28 30 32 ' .34 36 41.59 43.16 44.77 46.42 48.13 0.0114 0.0115 0.0115 0.0115 0.0116 0.973 0.939 0.9080.877 0.848 .14.32 14.76 15.21 15.65 16.10- 81.39 81.61 81.83 82.05 82.27 0.03143 0.03233 0.03323 0.03413 0.03502 0.16900 0.16887 .0.16876 0.16865 0.16854 85.02 85.25 85-48 85.71 85.95 0.17625 0.17612 0:17600 0.17589 0.17577 88.73 88.97 89.21 89.45 89.68 0.18328 0.18315 0.18303 0.18291 0.18280 38 49.88 " 0.0116 0.819 16.55 82.49 0.03591 0.16843 86.18 0.17566 89.92 0.18268 39 60.78 0.0116 0.806 16.77 82.60 0.03635 0.16838 86.29 0.17560 90.04 0.18262 40 51.68 0.0116 0.792 17.00 82.71 0.03680 0.16833 86.41 0.17554 90.16 0.18256 41 52.70- 0-0116 0.779 37.23 82.82 0.03725 0.16828 86.52 0.17549 90.28 0.18251 42 53.51 0.0116 0.767 17.46 82.93 0.03770 0.16823 86.64 0.17544 90:40 0.18245 . 44 ` 46 ` 48 ' 60 ' 62 55.40 67.35 59135 61.39 63.49 0.0117 0.0117 0.0117 0.0118 0.0118 0.742 0.718 0.695 0.673 0.652 17.91 18.36 18.82 19.27 19.72 83-15 83.36 .83:57 83.78 83.99 0.03859 0.03948 0.04037 0.04126 0.04215 0.16813 0.16803 0.16794 0.16785 0.16776 86.86 87.09 87.31 87.54 87.76 0.17534 0.17525 0.17515 0.17505 0.17496 90.65 90.89 91.1491.38 91.61 0.18235 0.18224 0.18214 0.18203 ` 0.18193 ' 54. 66 58 60 62 . 65.63 67.84 70.10 72.41 74.77 0.0118 0.0119 0.0119 0.0119 0.0120 0.632 0.612 0.593 0.575 0.557 20.18 20.64 21.11 21.57 22.03 84.20 84.41 84.62 84.82 85.02 0.04304 0.04392 0.04480 0.0456$ 0.04657 0.16767 0.16758 0.16749 0.16741 0.16733 87.98 88.20 88.42 88.64 ' 88.86 0.17486 0.17477 0.17467 0.17458 0.17450 91.83 92.06 92.28 92.51 92.74 0.18184 0.18174 0.18165 0.18155 0.18147 64 66 68 ; 70 72 ` 77.20 ` 79.67 82.24 84.82 87.50- 0.0120 0.0120 0.0121 0.0121 0.0121 0.540 0.524 0.508 0.493 0.479 22.49 . 22.95 23.42 23.90 24.37 85.22 85.42 85.62 85.82 86.02 0.04745 0.04833 0.04921 0.05009 0.05097 0.16725 0.16717 0.16709 0.16701 0.16693 89.07 89.29 89.50 89.72 89.93 0.17442 0.17433 0.17425 0.17417 0.17409 92.97 93.20 93.43 93.66 93.99 0:i8139 0.18130 ` 0.18122 0.18114 0.18106 74 90.20 0.0122 0.464 24.84 86.22 0.05185 0.16685' 90.14 0.17402 94.12 0.18098 76 93.00 0.0122 0.451 20.32 86.42 0.05272 0.16677 90.36 0.17394 94.34 0.18091 78 95.85 0.0123 0.438 25.80 86.61 0.05359 0.16669 90.57- 0.17387 94.57 0.18083 80 98.76 0.0123 0.425 26.28 86.80 0.05446 0.16662 90.78 0.17379 94.80 0.18075 82 101.70 0.0123 0.413 26.76 86.99 0.05534 0.16655 90.98 0.17372 95.01 0.18068 . 84 86 88 90 . .92. 104.8 ` 107.9 111.1 114.3 117.7 0.0124 0.0124 0.0124 0.0125 0.0125 0.401 0-389 0.378 0.368 0.357 27.24 27.72 28.21 28.70 29.19 87.18 87.37 87.56 87.74 87.92 0.05621 0.05708 0.05795 0.05SS2 0.05969 0.16648 0.16640 0.16632 0.16624 0.16616 91.18 91.37 91.57 91.77 91.97 0.17365 0.17358 0.17351 0.17344 0.17337 95.22 95.44 95.65 95.88 96.07 0.18061 0.18054 048047 0.18040 0.18033 Refrigeration 545 94 96 98 100 102 104 106 108 110 112 114 116 118 120 122 124 126 128 130 132 134 136 - 138 140 Abs. Pnn. Lb SyU 121.0 124.5 128.0 131.6 135.3 Table 1.... Properties of Dichlorodifhioromethane (CCi*Fi)` (Concluded) .wwu.a Liquid Vapor Enthalpy liquid Vapor Enthalpy and Entropy Taken From --40 F Entropy 25 F Superheat Liquid Vapor Enthalpy Entropy 0.0126 0.0126 0.0126 0.0127 0.0127 0.347 0.338 0.328 0.319 0.310 29.68 30.18 30.67 31.16 31.65 88.10 88.28 88.45 88.62 88.79 0.06056 0.06143 0.06230 0.06316 0.06403 0.16608 0.16600 0.16592 0.16584 0.16576 92.16 92.36 92.55 92.75 92.93 0.17330 0.17322 0.17315 0.17308 -0.17301 50 F Superheat Enthalpy Entropy 96.28 96.50 96.71 98.92' 97.12 0.180I28 0.18018 0.18011 0.18004 0.17998 139.0 142.8 146.8 150.7 154.8 0.0128 0.0128 0.0129 0.0129 0.0130 0.302 0.293 0.285 0.277 0.269 32.15 32.65 33.15 33.65 34.15 88.95 89.11 89.27 89.43 89.58 0.06490 0.06577 0.06663 0.06749 0.06836 0.16568 0.16560 0.16551 0.16542 0.16533 93.11 93.30 93.48 93.66 93.82 0.17294 0.1728S 0.17281 0.17274 0.17286 97.32 97.53 97.73 97.93 98.11 0.17993 0.17987 0.17982 0.17976 0.17969 158.9 163.1 167.4 171.8 176.2 0.0130 0.0131 ' 0.0131 0.0132 0.0132 0.262 0.254 0.247 0.240 0.233 34.65 35.15 35.65 36:16 36.66 89.73 89.87 90.01 90.15 90.28 0.06922 0.07008 0.07094 0.07180 0.07266 0.16524 0.16515 0.16505 0.16495 0.16484 93.98 94.15 94.31 94.47 94.63 0.17258 0.17249 0.17241 0.17233 0.17224 ' 98.29 98.48 98.66 98.84 99.01 0.17961 0.17954 0.17946 0.17939 0.17931 180.8 185.4 190.1 194.9 199.8 0.0133 0.0133 0.0134 0.0134 0.0135 0.227 0.220 0.214 0.208 0.202 37.16 37.67 38.18 38.69 39.19 90.40 90.52 90.64 90.76 90.86 0107352 0.07437 0.07522 0.07607 0.07691 0.16473 0.16462 0.16450 0.16438 0.16425 94.78 94.94 95.09 95.25 95.41 0.17215 0.17206 0.17196 0.17186 0.17176 99.18 99.35 99.53 99.70 99.87 0.17922 0.17914 0.17906 0.17897 0.17889 204.8 209.9 215.0 220.2 0.0135 0.0136 0.0137 0.0138 0.196 0.191 0.185 0.180 39.70 40.21 40.72 4fr24 90.96 91.06 91.15 91.24 0.07775 0.07858 0.07941 0.08024 0.16411 0.16396 0.16380 0.16363 95.56 95.72 95.87 96.03 0.17166 0.17156 0.17145 0.17134 - 100.04 100.22 100.39 100.56 0.17881 0.17873 0.17864 0.17856 to restore the .refrigerant to a condition in which it will pos sess the ability to extract heat from the space to be- cooled. For all compression-type systems the cycle consists of four' processes: heat gain in the evaporator; pressure rise in the compressor; heat loss in the condenser; pressure loss in the expansion valve. The compression process is accomplished at the expense of energy added to'the compressor in the form of shaft work, and the expansion process could be carried out, if the economics of the system would permit, in an expand ing engine with consequent release of energy as shaft work. In ordinary systems, however, the additional first cost and maintenance cost of an expanding;engine so greatly exceed the advantage resulting from the work realized, that such engines are not used, and instead, the pressure reduction is allowed to occur irreversibly in an expansion valve. Basically, then, a refrigeration cycle consists of two heat-transfer proc esses and two pressure-change processes, no work entering into the heat-transfer processes and--in the simple cycle-- no heat transfer occurring during the pressure-change proc esses. The most common and least complicated type of refrigera tion cycle is called the simple saturation cycle, and is shown diagrammatically in Fig. 3 and plotted upon pressure-en- . thalpy coordinates in fig. 4. For this system, saturated va por flows without gain or loss of heat from the evaporator to the suction of the compressor. During passage through the compressor the energy added as shaft work goes entirely to increase-the enthalpy of the refrigerant, and the compression process, which is assumed to occur reversibly and without external heat transfer, is characterized by constant entropy. Thus, the state of the superheated vapor leaving the com pressor can be determined from the tables of thermody namic properties by noting the discharge pressure and firing, also, the entropy of the saturated vapor at entrance to the compressor. ' Superheated vapor from the compressor flows to the con denser where de-superheating and condensation take place. From the condenser the refrigerant flows to the expansion valve, undergoes a constant-enthalpy pressure reduction, and returns to the evaporator where it again removes a quantity of undesired heat. When the evaporator is arranged to permit direct cooling of room air by the refrigerant, the system is said to be of tbe direct-expansion type, while a system in which the evaporating refrigerant cools water or brine, which in turn cools the air, is said to be indirect. Although many differences exist between most actual systems and that of the simple saturation cycle, this latter is, nonetheless, of great value m that it provides an extremely simple method of rap idly achieving an approximate analysis of probable power requirements, compressor size, etc. Further, the equations used in analyss of a simple saturation cycle form the basis of the more complex treatments required for compound re frigeration cycles. For these reasons a typical simple satura tion problem will be worked in detail. Example 1: A simple saturation cycle carries a 7-ton load when operating between suction and discharge pressure of 546 CHAPTER 38 1959 Guide Table 2-------Properties of Monochbrodifluoromethane (CHGFJ* Saf. hop. f Abt. Press. 15 per $9 fa. Volume Enthalpy Eathotpy and Entropy Taken from --40f Entropy 50 Pag Superheat 100 Deg Superheat - liquid Vapor liquid Vapor liquid Vapor Enthalpy Entropy Enthalpy Entropy 0 38.79 0.01192 1.373 10.63 105.02 0.0240 0.2293 112.35 0.2446 120.00 0.2590 .2 \4 5 .6 8 40.43 42.14 43.02 43.91 45.74 0.01195 0.01198 0.01200 0.01201 0.01205 1.320 1.Z70 1.246 1.221 1.175 11.17 11.70 11.97 12.23 12.76 105.24 105.45 105.56 105.66 105.87 0.0251 0.0262 0.0268 0.0274 0.0285 0.2289 0.2285 0.2283 0.2280 0.2276 112.59 112.83 112.95 113.07 113.31 0.2442 0.2438 0.2436 0.2434 0.2430 120.26 120.52 120.65 120.78 121.04 0.2586 0.2581 0.2579 0.2577 0.2572 10 47.63 0.01208 1.130 13.29 106.08 0.0296 0.2272 113.55 0.2426 121.30 0.2568 12 49.58 0.01211 1.088 13.82 106.29 0.0307 0.2268 113.79 0.2422 121.56 0.2564 14 51.59 0.01215 1.048 14.36 106.50 0.0319 0.2264 114.02 0.2418 121.82 0.2560 16 53.66 0.01218 1.009 14.90 106.71 0.0330 0.2260 114.25 0.2414 122.08 0.2556 18 55.79 0.01222 0.9721 15.44 106.92 0.0341 0.2257 114.48 0.2410 122.33 0.2552 20 22 24 26 28 57.98 60.23 .62.55 64.94 67.40 0.01225 0.01229 0.01232 0.01236 0.01239 0.9369 0.9032 0.8707 0.8398 0.8100 15.98 16.52 17.06 17.61 18.17 107.13 107.33 107.53 107.73 107.93 0.0352 0.0364 0.0375 0.0379 0.0398 0.2253 0.2249 0.2246 0.2242 0.2239 114.71 114.94 115.17 115.40 115.62 0.2406 0.2402 0.2398 0.2395 0.2391 122.59 122.84 123.10 123.35 123.60 0.2548 0.2544 0.2540 0-2537 0.2533 20 32 34 36 38 ' 69.93 72.53 75.21 77.97 80.81 0.01243 0.01247 0.01250 0.01254 0.01258 0.7816 0.7543 0.7283 0.7032 0.6791 18.74 19.32 19.90 20.49 21.09 108.13 108.33 108.52 108.71 108.90 0.0409 0.0421 0.0433 0.0445 0.0457 0.2235 0.2232 0.2228 0.2225 0.2222 115.84 116.07 116.29 116.52 116.74 0.2387 0.2383 0.2380 0.2376 0.2373 123.85 124.10 124.35 124.59 124.84 0.2529 0.2525 0.2522 0.2518 0-2515 40 83.72 0.01262 0.6559 21.70 109.09 0.0469 0.2218 116.96 0.2369 125.08 0.2511 42 86.69 0.01286 0.6339 22.29 109.27 0.0481 0.2215 117.18 0.2366 125.32 0.2508 44 89.74 0.01270 0.6126 22.90 109.45 0.0493 0.2211 117.40 0.2363; 125.56 0.2504 46 92.88 0.01274 0.5922 23.50 109.63 0.0505 0.2208 117.61 0.2359 125.80 0.2501 48 96.10 0.01278 0.5726 24.11 109.80 0.0516 0.2205 117.82 0.2356 . 126;04 0.2497 50 . 52 54 56 58 99.40 102.8 106.2 109.8 113.5 0.01282 0.01286 0.01290 0.01294 0.01299 0.5537 0.5355 0.5184 0.5014 0.4849 24.73 25.34 25.95 26.58 27.22 109.98 110.14 110.30 110.47 110.63 0.0528 0.0540 0.0552 0.0564 0.0576 0.2201 0.2198 0.2194 0.2191 0.2188 118.02 118.22 118.42 118.62 118.82 0.2353 0.2350 0-2347 0.2343 0.2340 126.27 126.50 126.73 126.96 127.19 0.2494. . 0.2491 0.2488 0.2484 0.2481 60 117.2 62 . 121.0 64 . 124.9 66 128.9 68 133.0 0.01303 0.01307 0.01312 0.01316 0.01320 0.4695 0.4546 0.4403 0.4264 0.4129 ' 27.83 28.46 29.09 29.72 30.35 110.78 110.33 111.08 111.22 111.35 0.0588 0.0600 0.0612 0.0624 0.0636 0.2185 0.2181 0.2178 0.2175 0.2172 119.01 119.21 119.40 119.59 119.77 0.2337 0.2334 0.2331 0.2327 0.2324 127.42127.65 127.87 128.10 128.32 0.2478 0.2475 0.2472 0.2469 0.2466 70 137.2 0.01325 0.4000 3Q.99 111.49 0.0648 0.216S 119.96 0.2321 128.54 0.2463 72 141.5 0.01330 0.3875 31.65 111.63 0.0661 0.2165 120.15 0.2318 128.76 0.2460 74 145.9 0.01334 0.3754 32.29 111.75 0-0673 0.2162 120.32 0.2315 128.97 0.2457 76 150.4 0.01339 0.3638 32.94 111.88 0.0684 0.2158 120.50 0.2312 129.19 0.2455 78 155.0 0.01344 0.3528 33.61 112.01 0.0696 0.2155 120.67 0.2309 129.40 0.2452 80 159.7 0.01349 0.3417 34.27 112.13 0.0708 0.2151 120.85 0.2306 129.61 0.2449 82 164.5 0.01353 0.3313 34.92 112.24 0.0720 0.2148 121.02 0.2303 '129.82 0.2446 84 169.4 0.01358 0.3212 35.60 112.36 0.0732 0.2144 121.18 0.2300 130.02 0.2443 86 174.5 0.01363 0.3113 36.28 112.47 0.0744 0.2140 121.34 0.2297 130.23 0 2441 88 179.6 0.01368 0.3019 36.94 112.57 0.0756 0.2137 121.50 0.2294 130.43 0.2438 Refrigeration 547 Table 2 .... Properties of Monochlorodiflaoromelbane (CH0FJ* (Concluded) Sat. Temp. F Abe. Press. IA pefSqtn. Valuta* . Enthalpy Enthalpy and Entropy Taken from --40 F Entropy 50 Deg Superheat liquid Vapor Liquid Vapor Liquid Vapor Enthalpy . Entropy 90 184.8 0.01374 0.2928 37.61 112.67 0.0768 0.2133 121.66 0.2291 92 190.1 0.01379 0.2S41 38.28 112.76 0.0780 0.2130 121.82 0.2288 94 195.6 0.01384 0.2755 38.97 112.85 0.0792 0.2126 121.97 0.2285 96 201.2 0.01390 0.2672 39.65 112.93 0.0803 0.2122 122.12 0.2282 98 206.8 0.01396 0.2594 40.32 113.00 0.0815 0.2119 122.28 0.2279 100 212.6 0.01402 0.2517 40.98 113.06 0.0827 0.2115 122.40 0.2276 102 218.5 0.01408 0.2443 41.65 113.12 0.0839 0.2111 122.53 0.2273 104 224.6 0.01414 0.2370 42.32 113.16 0.0851 0.2107 122.66 0.2270 106 230.7 0.01420 0.2301 42.98 .113.20 0.0862 0.2104 122.79 0.2267 108 237.0 0.01426 0.2233 43.66 113.24 0.0874 0.2100 122.92 0.2264 110 243.4 0.01433 0.2167 44.35 113.29 0.0886 0.2096 123.04 0.2261 112 249.9 0.01440 0.2104 45.04 113.34 0.08SS 0.2093 123.16 0.2258 114 256.6 0.01447 0.2043 45.74 113.38- 0:0909, 0.2089 123.28 0.2255 116 263.4 G.Q1454 0.1983 46.44 113.42 0.0921 0.2085 123.40 0.2253 118 270.3 0.01461 0.1926 47.14 113.46 0.0933 0.2081 123.51 0.2250 120 277.3 0.01469 Date bans Kusetig Cbemieilt, Ida, IMS. 0.1871 47.85 113.62 0.0945 * ABRB (Uistlin--Refrigerant Z2. 0.2078 123.62 0.2247 100 Deg Superheat Enthalpy 130.63 130.83 131.03 131.23 131.42 131.61 131.80 131.99 132.17 132.35 132.53 132.71 132.88 133.05 133.22 133-39 Entropy 0.2435 0.2432 0.2429 0.2427 0.2424 0.2421 0.2418 0.2416 0.2413 0.2411 0.2408 0.2405 0.2403 0.2400 0.2398 0.2395 52.7 psia and 121 psia with dichlorodifluoromethane, CCI'sFj'. as the refrigerant. Determine: (a) the cooling effect provided ' 'WT ia known from (b) and A*, is the enthalpy of refrigerant as it enters the compressor in a saturated vapor state at 52.7 by each pound of refrigerant; (b) the refrigerant circulating psia; thus Am' = 82.82. . '. rate; (c) the horsepower reauired; (d) the quantity of heat to be dissipated from the condenser; (e) the required condenser cooling water, in gallons per minute, if the temperature rise of water passing through the condenser is 8 deg; (/) the bore and stroke of a double acting cylinder (neglecting the effect of the piston rod) if speed of compressor is 500 revolutions per minute; (ff) coefficient of performance. - -'J ' ^ - In order to determine A* , the state of the refrigerant must first be determined at the compressor discharge. At the known suction state the entropy (from.Table 1 for saturated vapor at 52.7 psia) is 0.16828 and, since the compression is assumed to occur isentropically, it therefore follows that the discharge stage must have the entropy at 121 psia. From the table the entropy of vapor superheated 25 deg ia Q.1733G, so the super Solution: (o) Saturated liquid CC1*F* at 121 psia leaves the condenser and enters the expansion valve. The enthalpy of this . heat, la, possessed by the actual gas discharged compressor can be obtained by interpolation as, * from ' this material (from Table 1) is 29.68 Btu per pound, and this must . also be its enthalpy at entrance.to the evaporator. Leaving ' U _ 0.16828 - 0.16608 `. . the evaporator as a,saturated vapor at 52.7 psia, its enthalpy is 82.82, so the refrigerating effect must be 82.82 -- 29.68 = 53.14 25 ~ 0.17330 - 0.16608 Btu per pound. ^ . from which t* = 7.6 deg. ' - ' . ` (b) The'refrigerant circulating rate is equal to the total heat to be picked up in unit time, divided by the' pickup per pound of refrigerant or, - As the saturation temperature at 121 psia is 94 F the actual temperature, id , of the vapor leaving-the compressor is, 4* TM 94 + <w = 94 + 7.6 = 101.6 F. By.the same kind of interpola "W, - (7 ton'X 200) + 53.14-= 28.3 lb per minute. tion the enthalpy of the discharged vapor can be.determined from the enthalpies given for vapor superheated 25 F and for (c) The horsepower required is eaual to the increase in saturated vapor, - energy, of the refrigerant passing through the compressor (expressed in Btu per minute) divided by the conversion factor (Jw - 88.10) _ (0.16828 - 0.16608) 42.42, which is the number of Btu per minute corresponding to 1 bp, (92.16 - 88.10) " (017330 - 0.16608) (bp) - WAK, t *..) + 42.42 a) from which, hi " 89.34 Btu per pound. Then substituting in Equation 7, . where (hp) = 28.3 (8934 - 8232) -5- 42.42 - 4.03. (hp) *= horsepower. W, " refrigerant circulating rate in pounds per minute. Atf " enthalpy of vapor at condition of discharge from ` - compressor.' A., -- enthalpy of saturated vapor entering compressor. (d) The rate of heat loss from the condenser, Q., must be equal to the sum of the energies picked up by the refrig erant in the evaporator and the compressor, Qt =. 53.14 + (8934 -- 8232) -- 53.14 -+ 6.52 59.66 Btu per pound or 263 X 59.66 1569 Btu per minute. This same figure can, of course, be determined more directly by subtraction of the enthalpy 548 CHAPTER 38 1959 Guide Sot. Tnp. F Ah*. Pna. 15 pec Sq to. Table 3 .... Properties of TrkhJoromoqoftyoromemane (CGjF)1 Volume - Enthalpy tiiftojfpr and Entropy Taken from --40 f bttropy 25 F Superheat liquid Vapor liquid Vapor liquid Vapor Enthalpy Entropy 0 5 10 15 20 . 25 2.59 2.96 3.38 3.85 4.36 .4.94 0.01020 0.01024 0.01028 0.01032 0.01036 0.01040 13.700 12.100 10.700 9.530 8.490 7.580 7.81 8.81 9.82 10.80 11.90 12.90 90.4 91.2 92.0 92.8 93.7 94.6 0.0178 0.0200 0.0222 0.0243 0.0264 0.0286 0.1975 0.1974 0.1973 0.1971 0.1970 0.1969 93.9 94.7 95.5 96.3 97.2 98.0 0.2049 0.2047 0.2045 0.2043 0.2041 0.2039 30 35 40 . 45 ' 50 5 .SI 6.27 7.03 7.88 8.79 0.01045 0.01049 0.01053 0.01057 0.01062 6.770 6.080 5.460 4.920 4.440 13.90 14.90 16.00 17.00 18.10 95.3 96.1 96.8 97.6 98.4 0.0307 0.0328 0.0349 0.0370 0.0391 0.1969 0.1968 0.1968 0.1967 0.1967 98.8 99.6 100.3 101.1 101.9 0.2038 0.2037 0.2036 0.2035 0.2034 55 9.80 0.01066 4.020 19.10 99.2 . 0.0412 0.1967 102.7 0.2033 >00 10.90 0.01071 3.640 20.20 100.0 0.0432 0.1967 103.5 0.2033 65 12.10 0.01076 3.300 21.30 100.8 0.0453 0.1967 104.3 0.2032 70 13.40 0.01081 3.000 -22.40 101.5 0.0473 0.1967 105.0 0:2032 >75 14.80 0.01086 2.740 23.50 102.2 0.0193 0.1967 105.7 0.2031 80 85. 90 95 100 105 , 16.30 17.90 19.70 21.60 23.60 25.90. 0.01091 0.01096 0.01101 0.01106 0.01111 0.01116 2.500 2.280 2.090 1.918 1.761 1.620 24.50 25.60 26.70 27.80 28.90 30.10 102.9 103.6 104.4 105.1 105.7 106.4 0.0513 0.0533 0.0553 0.0573 0.0593 0.0613 0.1966 0.1966 0.1966 0.1966 0.1965 0.1965 106.4 107.1 107.9 108.6 109.2 109.9 0.2030 0.2029 0.2028 0.2028 0.2027 0.2026 50 F Superheat Enthalpy Entropy 97.4 97.2 99.0 99.8 100.7 101.5 0.2120 0.2117 0.2114 0.2111 0.2109 0.2107 102.3 103.1 103.8 104.6 105.4 0.2105 0.2103 0.2101 0.2099 0.2098 106.2 107.0 107.8 108.5 . 109.2 0.2097 0.2096 0.2094 0.2093 0.2092 109.9 110.6 111.4 112.1 112.7 113.4 0.2090 0.2089 0.2088 0.2087 0.2085 0.2084 . of liquid leaving the condenser from the enthalpy of super heated vapor going into it, this, . '' ! Qt - 26J3 (89.34 - 29.68) = 1569 Btu per minute..; . .. (e). The cooling water rate .(based on a gallon as'8-34 lb) is 1569 + (8 X 834) . 23.5 gpm. _ . . (J) The compressor sue is fixed by the volume of gas which must be drawn into the machine per unit time. Saturated vapor at 52.7 psia hna & specific volume, from Table 1, of 0.779 cu ft per pound, hence 2o3 X 0.779 ** 20.49 cfm of gas must be han dled. Assuming a volumetric efficiency of 90 percent, the com pressor must then displace 20.49 + 0.9 -- 22.8 cfm. The speed is given as 600 rpm and, as the unit is known to be double-act ing, the displacement is therefore (22.8 X 1728) -+ (2 X 500) ~ 39.4'cu in. JLf the unit were designed so that bore d and stroke were the'same, . (id*) +;4 39.4 d.~ 3.69 in. , ` (ff) . (CP) - (C - hJt) + (A. - h..) Z, - <82.82 - 29.68) + (89.34 - 8232) - 8.17 where &/ is the specifio enthalpy of liquid at discharge from the condenser. The coefficient of performance of Example 1 may be com pared with that of an ideal system operating on the Carnot cycle between the same temperature limits. Then T, = 501 F (which is 41 F + 460) and Tc = 554 F (which is 94 F + 460) and; . The actual cycle is therefore 8.17 '4- 9.6 or 85 percent as effective as a Carnot cycle between the same temperature limits. '. - Influence of Suction Pressure Brief consideration of the analytical procedure used in dis- cusion of the ample saturation cycle will bring out the need for marntflining the suction pressure on any refrigeration system as high as the load will permit. As the suction pressure increases, for fixed discharge pressure, the enthalpy of re frigerant entering the evaporator remains unchanged, but the leaving enthalpy increases and, hence, the refrigerating effect increases. Further, compressor energy input is reduced not merely because of the greater enthalpy of the gas at suction, but also because of a reduction in the enthalpy of the super heated gas at discharge. Since the refrigerating effect is greater and the work-less, it is obvious that there will be a substantial gain in the coefficient of the performance. See Chapter .54,'Fig. 1. ' The actual value of suction pressure on any system is ob viously determined by the required temperature which must be' maintained in the conditioned space. For a direct-expan sion system the evaporator can be held at a temperature not much less than that of the conditioned enclosure, except in cases where lower temperatures may be needed in order to establish a desired ratio of dehumidifying to cooling load. When dehumidification requirements dictate the use of un usually low evaporator temperatures, the increased operating cost should properly be charged against the dehumidification rather than the sensible cooling. .- Refrigeration 549 Temp F Pressure pa p*fe Tab!* 4 .... Properties of Trichlorotriftuoroethane (CjCljFj)* Volume Density Enthalpy from --4Q*F liquid cu ft/lb Vapor cu ft/lb liquid tb/oi ft Vapor Ib/cu ft liquid Btu/lb latent Btw/lb Vapor Bto/lb Entropy from -- 40*F liquid Btu/lb/ F deg Vapor Btu/lb/ F deg 0 0.8377 28.21* 0.00966 31.31 4 .9503 27.99* .00968 27.84 8 1.075 27.73* .00971 24.81 12 1.213 27.45* .00974 22.17 16 1.366 27.14* .00977 19.84 20 1.534 26.80* 0.00979 17.81 24 1.719 26.42* .00982 16.02 28 1.922 26.01* .00985 14.43 32 2.145 25.55* .00988 13.03 36 2.388 25.06* .00991 11.79 40 ' 2.655 44 2.944 48 3.258 52 3.602 56 . 3.973 24.52* 23.93* 23.29* 22.59* 21.83* 0.00994 .00997 .01000 .01003 .01006 10.68 9.703 8.830 8.044 7.342. 60 4.374 21.02* 0.01010 6.713 64 4.807 20.14* .01013 6.149 68 5.275 19.18* .01016 5.640 72 5.780 18.16* .01019 . 5.180 76 6.320 17.06* .01023 4.769 80 6.902 15.87* 0.01026 4.392 84 7.527 14.60* .01030 4.051' 88 8.194 13.24* .01033 3.742 92 8.908 11.79* .01037 3.463 96 9.668 10.24* .01040 3.208 100 10.48 104 11.35 108 12.28 110 12.70 8.59* 6.82* 4.93* 3.95* 0.01044 .01048 .01051 0.01053 2.976 2.762 2.567 - 2.477 * Ictchei at mercury below ooe ebnoepbere. 103.56 103.27 102.98 102.69 102.40 102.10 101.81 101.51 101.21 100.91 100.60 100.30 99.99 99.68 99.37 99.05 98.73 98.42 98.10 97.77 97.45 97.12 96.79 96.46 96.13 95.79 95.46 95.12 94.95 0.03194 .03592 .04031 .04511 .05040 7.98 8.78 9.59 10.41 11.22 0.05616 .06243 .06929 .07675 .08483 12.03 12.85 13.67 14.49 15.32 0.09361 .1031 .1133 .1243 .1362 16.16 16.99 17.82 18.66 - 19.50 0.1490 .1626 .1773 .1931 .2097 20.35 21.19 22.05 22.90 23.76 0.2277 .2468 .2672 .2888 .3117 24.63 25.49 26.36 27.24 28.11 0.3360 .3620 .3896 0.4038 28.99 29.89 30.78 31.22 70.92 70.68 70.44 70.20 69.96 69.72 69.48 69.24 69.00 68.75 68.50 68.25 68.00 67.74 -67.48 67.22 66.96 66.69 66.43 66.16 65.88 65.60 65.32 65.04 64.75 64.46 64.16 63.86 63.71 78.89 79.46 80.03 80.61 81.18 0.0182 .0199 .0216 .0234 .0251 0.1725 .1724 .1723 .1722 .1722 81.75 82.33 82.91 83.49 84.07 .0.0268 .0285 .0302 .0318 .0335 0.1722 .1721 .1722 .1722 .1722 84.65 85.24 85.82 86.40 86.98 0.0352 .0368 .0385 .0101 .0418 0.1723 .1723 .1724 .1728 .1727 87.57 88.15 88.74 89.33 89.92 0.0434 - .0450 .0467 .0483 .0499 0.1728 .1729 .1731 .1732 .1734 90.51 91.09 91.68 92.28 92.86 0.0516 .0531 .0547 .0563 .0578 0.1736 .1738 .1740 . .1742 .1744 93.45 94.05 94.64 94.93 0.0594 .0610 .0626 0.0634 0.1746 .1748 .1751 0.1752: Influence of Discharge Pressure . In contrast to suction pressure, the compressor discharge pressure should be kept as low as operating conditions will allow. This pressure must be high enough to provide a saturation temperature of refrigerant within the condenser that is greater than the exit temperature of the cooling water. The discharge pressure therefore is a direct function of the temperature of the cooling fluid, and will automatically rise whenever the temperature of cooling water (or air) rises; it will also rise when the flow rate of the cooling medium is decreased. * Increase in discharge pressure (for fixed suction pres sure) raises the enthalpy of the gas leaving the compressor; hence, increases the work of compression. Further, as the enthalpy of saturated liquid leaving the condenser increases with pressure, the refrigerating effect must decrease. Thus the effect of such a pressure rise is to require more work per pound of refrigerant handled, and at the same time to necessitate an increase in the refrigerant flow rate. (See Chap ter 54, Fig. 1.) Influence of Water Jacket The preceding discussion has, in every case, assumed lsentropic compression. Where exact performance data are not available, this assumption is a desirable one since it leads to a conservatively large determination of the power required. In most actual systems, the compression process departs from isentropic due to irreversible heat transfers which oc cur between the vapor in the cylinder and the cylinder wall, and *lsf> because of intentional heat dissipation from the outside of the cylinder walls to the surroundings,--or to a cooling fluid passing through a water jacket around the 550 CHAPTER 38 1959 Guide cylinder. Compressor cooling is highly desirable as a method of reducing power consumption. . Influence of Superheating and Subcooltng The most common departure from conditions of the simple saturation cycle is that resulting from admission of super* heated vapor to the compressor. Thermodynamically, super heat is undesirable because the enthalpy increase required to compress a vapor through a given pressure range in creases with superheat. Further, superheated vapor leaving an evaporator is usually an indication that the suction pres sure is lower than necessary. Under practical operating con ditions, however, superheat is almost universally used as a means of asuring complete vaporization of the refrigerant going to the compressor. With modern compressors operating at high speed, and with relatively small clearance space, it is particularly necessary to avoid admission through the suction valves of liquid refrigerant. _ . Another common departure of actual systems from the simple saturation cycle occurs because of subcooling of re frigerant in the condenser. Thermodynamically, such sub cooling is advantageous since it increases the refrigerating effect without affecting the unit energy requirements of the compressor. Further, it can be shown that for a fixed ratio of condenser cooling water to refrigerant circulating rate, the total compressor power requirements will be greater when operating at.simple saturation than when operating with maximum subcooling. What is even more surprising is that condenser pressure may be lower for the subcooling cycle than for the saturation cycle. This condition results from the fact that, for the same capacity on a heavily loaded con denser, the refrigerant flow rate is less when there is sub coding. Because of the advantages attendant upon the use of subcooling, many methods are in use for obtaining some subcooling effect outside of the condenser. One common pro cedure is to use the cold vapor leaving the evaporator to cool the liquid flowing from condenser to expansion valve. Another somewhat unusual subcooling cycle allows cold refrigerant from the downstream side of the expansion valve to cool liquid refrigerant from the condenser down to the evaporator temperature. Fig. 5 shows the pressure-enthalpy diagram for a typical refrigeration cycle operating with both subcooling of the refrigerant from the condenser and super heating of the refrigerant leaving the evaporator. Complex Refrigeration Cycles The preceding sections have dealt only with refrigeration systems in which there is but one evaporator; compression is accomplished through but a pgtp- stage, and expansion proceeds through a single expansion valve. In large systems or in low-temperature systems in which the compression ratio is high, the compression process can be carried out in stages, with the refrigerant passing through several cylinders arranged for operation in series. The thermodynamic ad vantage of such compound compression arises from the fact that intercoolers ,can be placed between the stages of com pression to extract heat from the vapor, and thereby cause the overall compression process to approach more closely the ideal condition of isothermal compression. Essentially, such intercoolers serve the same purpose as a cooling jacket, but with greater effectiveness because of the more satis factory heat-transfer conditions. In the simple saturation cycle the saturated liquid entering : the expansion valve commences to vaporize as soon as its pressure starts to drop. The vapor produced during the ex pansion process has no further use, in terms of refrigerating effect, since it has already picked up its latent heat of vaporization as a result of heat winch it has extracted from the unvaponzed residue. Thus the instant such vapor forms, its usefulness is at an end, and to allow such materia] to undergo a further drop in pressure is uneconomical. With compound compression, there is at least one intermediate pressure at which flash vapor can be extracted. In such cases several expansion valves ran be utilized with all of the refrigerant from the condenser passed through a first ex pansion valve to the higher suction pressure, and the vapor then extracted and returned to the condenser through the high compression stage. The remaining refrigerant ran then pass through a second expansion valve where the pressure is dropped to that corresponding to the low- pressure evaporator. The number of expansion valves is limited by the number of stages of compression. * Further cycle complications may arise if more than one evaporator is to be operated with a single compressor, and particularly, if the pressures in these evaporators are to differ. The most common solution is to operate the com pressor at the suction pressure of the lowest pressure evaporator, and to equip all other evaporators with back pressure regulating valves or throttling devices between the evaporator and the compressor suction. Saturation Cycle Refrigeration The Air-Cycle System Fundamentally, the air cycle* is essentially the same as the vapor cycle. Compression is accomplished by a recipro cating or centrifugal compressor, and, since there is no change of phase of the refrigerant upon expansion, an tar cooler replaces the condenser, and a refrigerator replaces the evaporator. Although some cooling would result from the expansion of the gas through an ordinary expansion valve, a much greater drop in air temperature is accomplished if the expansion is controlled to approach the isentropic by replacing the valve with an expansion engine or turbine. Furthermore, the work recovered by such an expansion engine ran be utilized to supply part of the work of com pression or to drive other devices. The Steam-Jet System The steam-jet system, under certain circumstances, is desirable for use in air conditioning.* Steam supplies directly the power used for compressing the refrigerant, thus elimi nating the losses connected with other methods of supplying energy. As the compression ratio between the evaporator and condenser under normal circumstances is large, the mechanical efficiency of the equipment is somewhat lower than that of the positive mechanical type compressor. The condensing water requirements are considerably greater, as 551 both the refrigerant and the impelling steam must be con densed. The steam-jet system functions on the principle that water under high vacuum will vaporize at low temperatures. Steam-jet boosters or compressors of the type commonly used in power plants for various processes,'will produce the necessary low absolute pressure to cause evaporation of the water. ' A diagrammatic representation of a typical steam-ejector water-cooling system is shown in Fig. 6. The figures cor respond to an average representative system. The water to be cooled enters the evaporator and is cooled to a tempera ture corresponding to the vacuum maintained. Because of the high vacuum, a small amount of the water introduced in the evaporator is flashed into steam. As this requires heat, and the only source of heat is the rest' of the water in the evaporator mnlq this other water is almost instantly cooled to a temperature corresponding to the boiling point de termined by the vacuum maintained. The amount of water flashed into steam is a small percentage of the total water circulated through the evaporator,' amounting to approxi mately 11 lb per (hr) (ton of refrigeration developed). The remainder of the water at the desired low temperature is pumped out of the evaporator and used at the point where it is required. The ejector compresses the vapor which has been flashed in the evaporator, plus any entrained air taken from the circulated water, to a somewhat higher absolute pressure. The vapor and air mix with the impelling steam on the dis charge side of the jet, and the total mixture then passes from the ejector into the condenser. The slight amount of air which may be entrained in the cooled water is removed by a small secondary ejector that raises the pressure sufficiently so that the air can be dis charged to the atmosphere. A secondary condenser is then necessary to.condense the steam in the secondary jet. While a single booster of smaller than 15 tons capacity is difficult to build, steam-jet vacuum-cooling units have been built for as small as 5 to 6 tons capacity. They can readily be built for steam pressures of from 5 to 200 psig, and condenser water temperatures as high as 90 F. The fig. 6 ..., Diagrammatic Arrangement of Steam-Jet Vacuum-Cooling Unit fig. 7.... Closed Absorption System . 552 CHAPTER 38 -1959 Guide steam consumption in pounds per hour per ton of refrigera tion increases rapidly as the booster steam pressure is low ered. For example, the lowering of the booster steam pres sure from 200 to 90 psig results in an increase in steam consumption of approximately 5 percent, whereas a further decrease in booster steam pressure to 10 psig increases steam consumption by approximately 72 percent over that required at 200 psig. The capacity of a steam-jet system is usually controlled by controlling the number of boosters in use since the unit usually has several boosters operating on the same evapo rator. Usually one booster is automatically controlled, whereas the others are manually operated. The capacity is dependent, as for all compressors, upon the evaporator temperature, or in other words, the suction pressure. For example, the capacity is lowered approximately 17 percent if the evaporator or chilled water temperature is lowered from 50 to 45 F. The capacity therefore can be controlled to some extent by regulating the evaporator temperature. from the evaporator tank to a spray header to wet the sur face of the coil. The evaporation and cooling effect of the spray on the coil surface chills the water as it is circulated through the coil in a closed circuit to a refrigeration load. In an actual operating cycle the salt solution is continu- The Absorption System . The absorption and mechanical compression cycles have in common the vaporizing and condensing of a liquid, but differ in that one has a compressor unit and the other an ab sorber-generator unit for producing the necessary pressure difference between vaporizing and condensing levels. Both cycles require energy for operation: mechanical energy for the compression cycle; heat for generation in the absorption cycle. Thermodynamic analysis of absorption cycles is relatively complex and requires the use -either of tables or graphs showing the equilibrium relationships and thermodynamic properties of the refrigerant-absorbent combination. Data of this kind are given in the first book in the bibliography. A discussion of various absorbents is given in the sixth book. Thermodynamically, the effectiveness of a refrigerant-ab sorbent combination increases directly with its negative de viation from Kaoult's Law. Fig. 7 shows a typical absorption cycle flow diagram. Cooling water first goes through the absorber (where it extracts tire heat of absorption which is liberated by the refrigerant vapor as it goes into solution), then through the condenser, and finally through the rectifier. Refrigerant from the evaporator enters the absorber where it goes into solution in the absorbent; the high concentration solution is then pumped to the generator where heat is supplied; the refrigerant (with some absorbent vapor) leaves for the recti fier and the warm low concentration solution is returned to the absorber. In the rectifier selective condensation oc curs, the concentration of the absorbent in the condensate being much greater than its concentration in the entering vapor mixture; rectifier condensate is dripped back to the generator. Operating Cycle. The components of one form of lithium bromide water absorption system are illustrated in Fig. 8. Diagram .A shows two closed vessels, with salt (lithium bromide) solution in one and water in the other. The salt solution in the absorber has affinity for water vapor and evaporates some of the water. The water that remains in the evaporator is thus cooled by evaporation, thereby pro ducing a refrigeration effect. . Since these two vessels operate under a high vacuum, chilled water temperatures down to 38 F may be obtained. To utilize the refrigeration effect, a coil is placed inside the evaporator as shown in diagram B. A pump circulates water Fig. 8 .... Components of Lithium Bromide Absorption System Refrigeration 553 PCACCMT or RATES CAPACITY fig. 11 .... Condenser Water Requirements for a Typical Lithium Bromide Absorption System ally absorbing water vapor, thus diluting the solution and reducing its ability to absorb additional water vapor. To keep the salt solution in the absorber at the proper strength a generator is added to the system as shown_in diagram C. The weak solution is pumped from the absorber to the generator where heat is used to boil off the exces water vapor. The reconcentrated salt solution is then returned to the absorber to continue the cycle. ' The water vapor boiled off in the generator is condensed and returned to the evaporator.- A heat exchanger is added to the system (diagram D) to conserve heat in the cycle by using the hot concentrated salt solution from the genera tor to preheat the cooler weak solution from the absorber. Condensing water from a cooling tower or other available source is circulated through coils in the absorber and con denser to remove waste heat from the refrigeration cycle. For the sake of simplification, the cycle is shown as operat ing with four separate chambers. In actual practice, the condenser and generator are combined into a high pressure fihp.ll, with the absorber and evaporator located in a second shell. Fig. 9 schematically shows the arrangement. A purge unit is included to remove any non-condecsables from the machine, thus assuring maTT^nm efficiency and capacity at all times. Coefficient of Performance. The coefficient of performance (CP) of an absorption system using lithium-bromide and water is approximately 0.6. The heat required can be ob tained from steam, hot water or other heated liquids. Absorption type equipment is fully automatic from full load to no load. The performance does not vary greatly be tween 20 percent of capacity and full load. The operating costs of absorption equipment are considered competitive with those of other forms .of refrigeration. For a typical lithium-bromide-water system, Figs. 10, 11, and 12 illus- fig. 10 .... Performance Characteristics of a Typical Lithium Bromide Absorption System Fig. 12.... Steam Requirements for a Typical Lithium Bro* mide Absorption System . 554 CHAPTER 38 1959 Guide trate respectively the performance characteristics, the con denser water requirements, and the steam requirements. BASIC REFRIGERATION EQUIPMENT Compression Refrigeration Machines Compression of the refrigerant gas drawn from the evapo rator may be accomplished by one of several means. Positive displacement may be used as in the reciprocating; oentrifug&l force may be applied as in the centrifugal compressor; an ejector may be used as in the steam jet refrigeration cycle; or absorption of a low pressure refrigerant gas in a secondary fluid, followed by the absorbent's release upon application of heat, may be utilized. A detailed discussion of the equipment required for each of these types of systems is beyond the scope of this chapter. For a more comprehensive treatment, reference may be made to the bibliography. The present discussion is limited to positive displacement re ciprocating compressors, and centrifugal .compressors. Rg. 13 .... Diagrammofic View of a Reciprocating Compressor Reciprocating Compressors . Reciprocating compressors (see Fig. 10) may be classified according to (a) cylinder design, (6) compressor drive, (c) valves, and (d) lubrication and cooling. Cylinder Design. Cylinder design may vary as to number, arrangement, and action (i e-> single-acting or double-acting). Single-acting compressors usually have their cylinders or- ranged vertically, radially, or in a V or W shape arrangement. Double-acting compressors, with refrigerant gas drawn in, and compressed on both the head and crank ends of the cyl inder, are usually arranged horizontally. Reciprocating units are available with from one to sixteen cylinders with the V, W, or radial arrangements best adapted to the greatest num bers. The present trend is toward higher operating speeds with a low displacement per cylinder, together with an increase in the number of cylinders. Whereas the original reciprocating compressors were slow-epeed (50 to 55 rpm) steam-driven devices, modem electric motor-driven compressors range up to 3500 rpm. Cylinder heads are usually bolted tight to the cylinders, but in some large compressors where there is danger of wet compression or of foreign materials entering the com pressor space, a secondary head known as a safety head, may be seated at the end of the cylinder and held in position with heavy springs. Normally, this head remains stationary, but excessive pressures in the clearance space are relieved by movement of the safety head, and thus prevent damage to the cylinder. Compressor Drives. Reciprocating compressors may be sub divided on the basis of souree of motive power, and whether they are open or hermetic. Practically all modem compressors are electric motor-driven, although a few large, steam-driven compressors are still being installed where steam forms the most economical source of energy. ' For summer air conditioning, the compressors may be driven by medium-speed heavy-duty internal combustion engines using natural gas as the fuel. Field tests indicated that fuel consumption of natural gas engine compressor drives is 13,000 Btu per ton-hour. , The natural gas engine compressor drives are designed as packaged units which combine engine speed variation and compressor cylinder unloading to meet fluctuating cooling requirements. Fuel consumption is in direct proportion to the actual cooling load throughout over 80 percent of the capacity range. The division of compressors into open or closed types is dependent upon whether the motive power is received from an external source, or whether the motor is direct drive and sealed within the housing. In the open type, power is applied from an external source to one end of tne compressor crank shaft extending through the crankcase, usually by means of a V-belt drive. The point of emergence of the shaft from the crankcase forms a weak point of refrigerant leakage, and is most frequently sealed with a bellows type crankshaft seal. Horizontal double-acting compressors operate with a sliding piston rod, moving back and forth through a stuffing box. H the motor is direct-drive and enclosed within the compressor housing, the compressor is classified as closed or hermetic. This eliminates the necessity of any shaft seal, and not only prevents refrigerant leakage at this point, but reduces oper ating noise. One disadvantage is the inaccessibility of moving Earts for repairs, but lubrication is greatly simplified since oth the motor and compressor operate in a sealed space con taining the lubricating oil. Compressor Valves. All refrigeration compressor valves are dependent for their operation upon a difference in pressure between the inside of tne cylinder and the suction or discharge line. Although mechanically-operated valves might have some advantage, they have proved unsatisfactory because each change in the evaporator or condenser-operating pressures requires a change of valve setting. The pressure differentials required for operation of the valves depend upon the valve design and the compressor speed. The suction and discharge valves may be arranged with both located in the compressor head, or with the suction valve on the top of the piston and the discharge valve in the compressor head (uniflow arrange ment). The valves themselves are usually classified as either poppet, ring-plate, or flexing. ' Lubrication and Cooling. Lubrication of modem compressors is accomplished by either splash lubrication or forced lubrica tion. The latter is used on large compressors, while simple splash lubrication is used in the smaller units'. Large compressors are usually water-cooled with the water jacket either cooling the cylinder walls, or both the cylinder walls and the compressor head. Small compressors are either waterPooled or air-cooled with extended finned surfaces cast on the exterior of the cylinder. In a few cases small compres sors may be found in which there is no attempt to add any purposive cooling other than through non-finned surfaces to the lower temperature air. Water cooling is more effective than air cooling, but even under the best conditions cylinder cooling removes only a portion of the superheat in the refrigerant gas. This removal of heat from the cylinder results in some decrease in the work of compression, as well as reduction in condenser load. Control of Reciprocating Compressors Capacity Control of reciprocating compressors to match the imposed load is accomplished by a controller responding to load variations, and operating one of the several means for changing the compressor capacity. This controller may respond to the condition being controlled, such as space temperature in the case of a direct-expansion system, or water temperature in the case of a water chiller; or it may Refrigeration 555 respond to suction pressure, which varies with the imposed load. The common methods of varying the compressor ca pacity are: 1. Starting and stopping the compressor. Tins is more common on smart units where frequent cycling of the compressor offers no serious complications. On large installations two or more smaller compressors may be employed and these may be started and stopped in sequence, thus providing more capacity steps: Sequence control of multiple compressors is accomplished oy the use of a program or step controller, and in most cases this is arranged to return to tne off position when the system is shut down or in the event of power failure, and to provide a suitable time delay between steps on start-up to prevent the full electrical load from being thrown across the line at one time. Means for manually or automatically varying the se quence to equalize wear on the compressors are sometimes employed. 2. Cylinder Unloaders. These usually are available on all but the smaller compressors and are used on both single and multiple compressor installations. They consist of a device built into the cylinder head to hold the suction valve open for unloading the cylinder. Oil pressure or head pressure is applied to these devices to load the cylinders, hence the compressor always starts at minimum capacity. Depending upon the make of compressor, the application of pressure to the unloaders is accomplished by: a. Solenoid valves usually operated by the program con troller in sequence with starting and stopping of the com pressor or compressors. The program controller starts the compressor at minimum capacity, then loads the cylinders in sequence as the demand increases. If more than one com pressor ts used, it starts and loads the second compressor in sequence after the first is fully loaded, etc. b. A self-contained stepping valve built into the compres- . sor and actuated by a bellows measuring suction pressure. This valve is supplied with oil pressure from the compressor oil pump and has an oil outlet connection to each cylinder unloader. This valve supplies oil pressure to; 'or releases it from, the cylinder unloaders progressively as the suction pressure increases or decreases. The suction-pressure bellows is opposed by a spring which has an external manual adjust ment for selection of the desired operating range. The other side of the bellows may be open to atmosphere so that the suction pressure is controlled with reference to atmospheric pressure, or it may be sealed and provided with an air con nection winch permits variation of the operating range as a function of air pressure from a pneumatic controller. For example, if the spring is so adjusted that the basic operating range is 35 to 40 psi suction pressure when the pressure from the pneumatic controller is zero, it will be increased to 45 to 50 psi when the control pressure is 10 psi. Thus these self-contained cylinder unloaders not only can control the suction pressure.within a fixed range, but this range can be moved up or down automatically to meet the varying de mands on the system. Pneumatic controllers used for this purpose often are supplied with air pressure up to 25 psi to permit a wide range of suction pressure variation. Most of these self-contained cylinder unloaders also can be arranged for mechanically varying the suction pressure by means of an electric motor operator acting against the manual ad justment spring to permit the use of proportional electric or electronic controls. 3. Speed.Control. Multi-speed motors are sometimes used, actuated by & multi-stage thermostat or a proportional thermo stat and a program or step controller. Safety Controls are provided on reciprocating compressors to stop the motor whenever certain conditions are outside of safe limits. These conditions include: 1. Low Suction Pressure. This is a pressure controller re sponsive to the suction pressure. It stops the compressor when the suctiqp pressure drops below a safe limit. It is sometimes also used as a capacity control, as described in preceding sec tion, paragraph numbered 1, when it is desired to start and atop the compressor in accordance with the load demand as determined by changes in suction pressure. When other means are provided for starting and stopping the compressor in accordance with load, the low-pressure control functions solely as a safety device. 2. High Head Pressure. This is a pressure controller re sponsive to the high-side pressure. It stops the compressor when the high-side pressure exceeds a safe limit. This is strictly a safety derice and frequently is of the manual-reset type so that the compressor cannot again start until the reset button is manually operated. In many cases the high- and low-pressure switches are combined into a single unit. 3. Low Oil Pressure. This is a pressure controller which stops the compressor in the event of tow oil pressure. It also is fre quently of the manual-reset type. 4. Low Line Voltage. This is a low-voltage cutoff which stops the compressor when the line voltage drops below a minimum value. 5. High Motor Current. This may be built into the motor or into the motor starter. It stops tne motor in the event exces sive current persists for more than the brief interval required in starting. 6. High Pressure Relief. This is a device for preventing damage if excessive head pressures are encountered, and pro vides protection from damage beyond that provided by the high-pressure cutout. It may be a relief plug which blows out in the event of excessive pressure. This has the disadvantage of losing the entire refrigerant charge. A relief valve, which functions like a pop-safety valve, is preferred since it wastes only enough refrigerant to relieve the danger. 7. Law Water Temperature. If the compressor is used for chilling water, a low-limit thermostat usually is installed in the chiller to stop the compressor in the event a freezing tem perature is approached. This is in addition to a controlling thermostat which also may respond to water temperature. Centrifugal Compressors Centrifugal compressors are used with very low pressure refrigerants; sometimes both evaporator and condenser work below atmospheric pressure. Trichlorotrifluoroethane (CiCUF.) and monbfluorotrichloromethane (CQF) are the refrigerants commonly used in centrifugal machines. Centrifugal compressors, like reciprocating compressors, can be divided into two general types, open and enclosed. In general, the open-type compressor is geared to the driving mechanism, and operates at higher speed than the driving 556 CHAPTER 38 1959 Guide motor or turbine. A modem, completely enclosed, directdriven centrifugal compressor is illustrated in Fig. 14. Compression of the refrigerant is accomplished by means of centrifugal force; therefore, this type of compressor is inherently suitable for large volumes of refrigerant at low pressure differentials. Two or more stages are usually re quired and high speeds are necessary to obtain good efficiency. The evaporator is usually constructed as an integral part of the centrifugal-type condensing unit, to chill water which is then circulated to the air-conditioning system. This is done because it would not be economical to pipe these large volumes of refrigerant any distance. Centrifugal refrigeration compressors are particularly well suited to direct steam-turbine drive because of their high operating speed. Water cooling equipment of one design is operated between 3500 and 4000 rpm for unite developing 1000 to 2000 tons capacity, and from 7000 to 8000 rpm for units developing 100 to 200 tons capacity. However, a great many applications, particularly in the smaller sizes, are electric motor-driven and equipped with standard gear-type speed increasers. Centrifugal systems are particularly well adapted to large capacities (up to 3000 tons) although it is also possible to secure units as low as 50 tons in rating. Because centrifugal units operate best with refrigerants possessing a high specific volume, and because of the simplifi cation of lubrication difficulties, they are frequently used for extremely low temperature applications. They are adaptable to a wide range of temperatures from --130 F to 50 F. One important advantage is their flexibility under varying loads, since units may be designed to operate with reasonable efficiency at capacities as low as 20 percent of normal load. Control of Centrifugal Compressors Capacity Control usually is accomplished by a controller actuated by the chilled water temperature or evaporator pressure and either (1) varying the flow of vapor from the chiller to the compressor or (2). varying the compressor speed. 1. Vapor flow control for compressors driven by constantspeed motors is accomplished by the use of suction dampers or inlet vanes which are positioned by automatic operators to maintain constant water temperature leaving the chiller or constant suction pressure in tne evaporator. 2. Speed Control for compressors driven by constant-speed motors may be accomplished through the use of an eddy cur rent clutch or a hydraulic coupling under control of an auto matic operator, variable-speed motors for speed control are more common on the larger machines. Steam turbines for' driving compressors can operate at various speeds under con trol of an automatic valve in the governor oil circuit. Safety Controls provide protection for the compressor by stopping the motor or reducing the capacity through the capacity-control system. Those which usually stop the motor are similar to those described for reciprocating compressors and respond to (1) low oil pressure, (2) low refrigerant tem perature, (3) low chilled water temperature, (4) high con densing temperature, (5) high motor temperature, (6) high motor current, and (7) low line voltage. Frequently controls are used that are actuated by some of these conditions to re duce capacity before the limit is reached in order to prevent system shutdown. ' In addition to the above safety-controls most centrifugal machines have thermostatically controlled heating and cool ing of the oil, and some have water-cooled motors with the water sometimes thermostatically controlled. Usually there is a system of interlocks which prevents the compressor from starting unless the condenser water pump and the chilled water pump are running. Condensers Condensers used for liquefying the refrigerant are of three general types: (1) air cooled, (2) water cooled, and (3) evaporative. 1. Air-Cooled Condensers are readily available in unitary equipment in capacities up to 20 tons of refrigeration. They are also available os separate assemblies for Meld-assembled systems in capacities up to over 100 tons per condenser. Air cooled condensers first became popular on self-contained room air conditioners and they are now used almost exclusively on this type of equipment. The use of air-cooled condensers for larger equipment was introduced only recently but is rapidly gaining m usage where an adequate water supply is costly to obtain or where other water problems are encountered. The conventional air-cooled condenser consists of an ex tended-surface coil across which air is blown by a fan. The hot discharge gas enters the coil at the top and, as it is condensed, flows to a receiver located below the condenser. Air-cooled condensers should always be located In a well ventilated space so that the heated air may escape and be replaced by ambient temperature air. When adequate supply of city or acceptable well water is readily available at a moderate cost, it is still the preferred condensing medium. However, where some form of water saving is required, the air-cooled condensers are rapidly gain ing favor over the cooling tower and evaporative condenser methods in the smaller and medium tonnage classes. Where some form of water saving is required, the capacity of the equipment, under the design conditions of higner wet-bulb weather in the case of cooling towenrand evaporative conden sers and higher dry-bulb in the case of air-cooled condensers, must be taken into account. The air-cooled condensing equip ment does have a higher peak current demand per ton over tne cooling tower and evaporative condenser methods, but there is some evidence that in actual installations, it does not have any materially higher seasonal power consumption per ton than the other methods of water saving in the warm-humid and hot-humid areas. The principal advantages of the air cooled condensers are low installation costs, lower maintenance costs and simplicity, and for these reasons they are used almost exclusively in small self-contained units and frequently'in the larger sizes of compression refrigerating equipment. 2. Water-Cooled Condensers are commonly used with com pressors of one horsepower or larger in size, and they are found almost exclusively on large installations. Although watercooled condensers may be of many designs, the shell-and-coil and the shell-and-tubc are most commonly found in present day practice. The amount and temperature of the condensing water deter mine the condensing temperature and pressure, and indirectly the power required for compression, it is therefore necessary to determine a balance so that the quantity of water insures economical compressor operation. City water is often used as the condensing medium in the smaller capacities providing an adequate water supply and means for its disposal are available, its cost is not prohibitive, and there are no restrictions against its use. Because there is a decided trend toward restricting the use of city water for air conditioning and refrigeration purposes, cooling towers are almost universally used with water-cooled condensers in the larger sizes- Since cooling towers produce the warmest condensing water during periods of greatest load, the refrigeration equipment must be designed to meet the maxi mum load at abnormal condensing water temperature. This makes little difference in efficiency of operation except at those times when the condensing water temperature is highest. Id many localities this occurs for only about 5 per cent of the entire cooling period and can be disregarded as a factor in establishing yearly operating costs. Further information on cooling towers is contained in Chapter 40. 3. Evaporative Condensers provide another means of con serving water used for condensing purposes. In effect they combine the condenser and cooling tower in a single unit. Refrigeration The fan draws air over the condenser coil which is kept wei by a water spray. Evaporative condensers are made in sizes up to 300 tons or more. They must be located where air is available and usually at not too great a distance from the compressor to avoid long refrigerant tines. Like cooling towers they result in least effi ciency at periods of maximum load. Chapter 40 provides addi tional information on evaporative condensers. Evaporators and Coolers Refrigeration evaporators must be designed for efficient removal of heat from the medium being cooled, as well as effective boiling of the refrigerant and a minimum drop of pressure through the coil. There are two general types of evaporators, dry and flooded. In the dry evaporator the re frigerant enters in the liquid state, and the design provides for complete evaporation with the vapors leaving slightly superheated. In flooded evaporators not all of the refrig erant is evaporated, the liquid-vapor mixture leaving the evaporator flows into a surge drum from which the vapors are drawn into the compressor suction line, and the liquid is recirculated through the evaporator. The types of coolers used in connection with air-condition ing work fail into three general groups: (1) direct water coolers, (2) direct air coolers, and (3) brine coolers for circulation of the brine in a closed system, and thus cooling indirectly either water or air. 1. Water coolers. One method of the direct cooling of water is to install direct expansion coils in the spray chamber so that the water sprayed into the air comes in direct contact with the cooling coils. Another common and efficient method of cooling spray water is to use a Baudelot type of heat ab sorber where tne water flows over direct expansion coils at a rate sufficiently high to give efficient beat transfer from water to refrigerant. Another type of spray-water cooler is the shell-and-tube heat exchanger in which the refrigerant is expanded into a shell enclosing the tubes through which the water flows. The velocity of the water in the tubes affects the rate of heat trans fer, and as the refrigerant is in the shell completely surround ing the tubes at all times, good contact and a high rate of heat transfer are insured. The disadvantage of such a system is that with the falling off of load on the compressor, the suction temperature or the temperature in the evaporator drops, and there is a possibility of freezing the water in the tubes, which, of course, might split the tubes and allow the refrigerant to escape into the water passage- This danger can be eliminated by automatic safety devices. Another system of cooling spray water is to submerge coils in the spray-collecting tank, or .in a separate tank used for storage. The heat transmission through the walls of the coils, however, is low and a great deal more surface is required than for any other type of cooler. However, with large storage tanks this type of cooling can be utilized to advantage. 2. Air coolers. When direct cooling of air is employed, the refrigerant is inside the coil and the air passes over it. Cooling depends upon convection and conduction for removing the heat from the air. The type of coil used can be either smooth or finned, the finned coil being more economical in space re- ?[uirement than the smooth coil. The fins, however, must be ar enough apart so as not to retain the moisture which con denses out of the air. When refrigeration evaporators are used for cooling air.or other gases by forced convection, they are usually termed blast coils or unit coolers. A blast coil may be placed in a duct or in an assembled unit, and the air forced across the coil and discharged through distributing ducts or directly into the space to he conditioned. Unit coolers, designed much like unit heaters, consist of a finned coil, propeller fan, and con trols suspended directly in the space to be cooled. 3. Indirect brine coolers. The indirect cooler, where brine is cooled by the refrigerant and the resulting cold brine is used to cool either air or water, introduces several other considera tions. It is not the most economical from a power consumption 557 standpoint, as it is necessary to coo! the brine to a temperature sufficiently low so that there is an appreciable difference be tween the average brine temperature and that of the substance being cooled. This requires that the temperature of the re frigerant must be still lower, and consequently the amount of power required to produce a given amount of refrigeration increases due to the higher compression ratio. There are other considerations which make such a system desirable. In the first place, where a toxic refrigerant is undesirable or cannot be used because of fire or other risks, especially in densely populated areas, the brine can be cooled in an isolated room or building and can then be circulated through the air-con ditioning equipment. This arrangement eliminates any possi bility of direct contact between the air and refrigerant. REFRIGERATION CONTROL Expansion Devices Id addition to means of controlling the compressor capacity and the necessary limit and safety controls as Rg. 15.... Typical Thermostatic Expansion Valve outlined under the section describing the compressors, re ciprocating compressor refrigeration systems require a de vice for controlling the expansion of the refrigerant from the high liquid pressure to the low evaporator pressure. Automatic Expansion Valves. An automatic or pressurecontrolled expansion valve operates to maintain a constant pressure in the evaporator. The liquid refrigerant paaseB through an orifice, the opening size of which is controlled by means of a needle valve connected to a flexible bellows. This bellows expands or contracts with variations in the evaporator pressure transmitted to the expansion chamber through the refrigerant outlet from the evaporator. The position of this needle valve is controlled by the degree of compression in an adjusted spring, balanced against tne bellows, and these two forces operate to maintain a constant pressure in the evapora tor by increasing or decreasing the flow of liquid refrigerant. Such an expansion valve is usually applied to evaporators of the direct-expansion type, but is not satisfactory for fluctuat ing loads such as are encountered in air-conditioning instal lations. Thermostatic Expansion Valves. A thermostatic expansion. valve controls the flow of liquid refrigerant to the evaporator go as to maintain the entire coil filled with evaporating' re frigerant, and to keep a constant superheat in the refrigerant gas leaving the coil. The construction of such a valve is shown m Fig. 15 and is milar to that for an automatic expansion valve but incorporates, in addition, a power element responsive to changes in the degree of superheat of the refrigerant gas leaving the coil. This power element consists of a bellows con nected^by means of a capillary tube to & feeler bulb fastened to tiie suction tine from the evaporator. The bulb, bellows, and tube are usually charged with the same liquid refrigerant used in the evaporator itself. A starved condition in the evap orator results id a greater superheat in the gas leaving the S' 558 CHAPTER 38 1959 Guide evaporator, aod this in turn operates through the power ele ment to increase the flow of liquid refrigerant. A flooded evap orator reduces the discharge superheat, and thus tends to reduce the flow of liquid refrigerant. Such an expansion valve is satisfactory for operation with fluctuating loads since this type of control tends to keep the evaporator filled with re frigerant at all times. Loo-Side Float Valves. A liquid refrigerant control of the low-side float valve type consists of a ball float located in either a receiver or the evaporator itself on the low-pressure side of the system- A needle valve, operated through a simple lever attached to the float, permits the passage of more or less refrigerant, as the level to the receiver or the evaporator fluctuates. Such a control must be used'in con junction with a flooded evaporator, and has been applied ex tensively to household refrigerators and, to some extent, in commercial and industrial installations. High-Side Float Valve*. A high-side float valve differs from a low-side float valve in that the float is located in a receiver or container on the high-pressure side of the system. Proper operation again depends upon metering of the refrigerant through a controlled opening, depending upon the level of the liquid refrigerant in the container. Such a control has the disadvantage that the evaporator must be placed directly adjacent to the float container, or some intermediate pressure device must be applied to prevent flashing of the refrigerant upon pressure drop. Capillary Txibes. A capillary tube may be used as a liquid refrigerant expanding device. Such a device consists of an extremely small bore tube (in the order of 0.04 inch in diam eter) of five to twenty feet in length. Although such a restrict ing device operates ss a very simple of expanding the liquid refrigerant, it has the disadvantage that no modifica tions are possible to Adjust the rate of expansion under various operating conditions. The bore and length of the tube, as well as the proportions of the rest of the system, are critical. It is for these reasons that its application has been limited to fac tory-assembled domestic ana commercial units. Refrigerant Row Control The capacity of the refrigeration system must be con trolled in accordance with the load imposed on the system. Except for those cases where the compressor is started and stopped by a thermostat responding to load conditions, some form of control of the refrigerant flow is usually required. Controlling the flow of refrigerant in accordance with the load may be accomplished in a number of ways, some of which are: 1. Solenoid calces are frequently used for control of gas or liquid flow. A solenoid valve is placed in the liquid line ahead of the expansion valve. It is closed whenever the compressor is not in operation and thus leakage into the evaporator is prevented, ur most cases it is controlled by a thermostat re sponding to the load. Solenoid liquid valves are widely used for control of refrigerant flow to individual evaporators in a multiple evaporator system operated by one compressor. The compressor capacity is controlled separately by a controller responding to suction pressure- Solenoid liquid and suction valves are sometimes used to isolate an evaporator completely for defrosting purposes. When solenoid liquid valves are used for controlling refrig erant flow, a pump-down cycle of control is often employed. The thermostat closes the solenoid liquid valve and the com pressor then pumps down until stopped by the low-euction pressure switch. The compressor, cannot restart until the thermostat again opens the solenoid liquid valve. 2. Expansion Valve Modulation. This form of flow control utilises the throttling characteristics of the expansion valve to starve the coil under reduced-load conditions. This may be accomplished by a device attached to the expansion valve or a pilot control which varies the setting of the expansion valve by changing the pressure in the equalizer line. Either of these are actuated by a controller sensitive to load conditions and the compressor capacity control is from suction pressure. Since short-cycling of the compressor is apt to occur if the flow of refrigerant is reduced too mueh, some limit to prevent this is required. 3. Evaporator Pressure Control is accomplished by back pressure valves. These are placed in tbe suction line between the evaporator and the compressor, and maintain the evap orator pressure constant by regulating the amount of vapor drawn from the evaporator. Tire compressor capacity is con trolled from suction pressure at the compressor. The use of back pressure valves permits a lower pressure at the compres sor than would be permissible at the evaporator, thus mini mizing short-cycling. On a multiple-evaporator system served by one compressor, the evaporators may be maintained at different temperatures. Back pressure valves can be equipped with an air connection for automatically varying the evap orator pressure in accordance with the demands of a pneu matic controller. Means for mechanically readjusting the valves by use of s proportioning electric operator also are available. Condenser Control The majority of refrigeration systems, other than frac tional horsepower, use water-cooled rather than air-cooled condensers. Condenser control is used' for the purpose of conserving water or limiting the condenser pressure, or both. Solenoid water valves on small compressors, or pneu matic or electric valves on larger compressors, are usually controlled simultaneously with starting or stopping of the compressor. A pressure-operated valve will provide pro portional control of water flow in response to condenser pressure. Similar water valves controlled thermostatically by the temperature of water discharged from the condenser are sometimes used- Evaporative condensers may be con trolled by an automatic damper responding to a condenserpressure controller. Cooling tower fans sometimes are started and stopped by a thermostat in the condensing water or a pressure controller in the condenser. Some form of freeze protection for evaporative condensers and cooling towers is necessary if they are required to operate in cold weather. Refrigeration Control for Air Conditioning When refrigerating equipment is used for space cooling, two major control problems exist: one is control of the temperature and tbe other, control of the humidity. In some applications the amount of latent heat to be removed is small compared with the sensible heat. In such cases, sufficient dehumidification will usually occur without any special provisions. In other cases, such as theaters, where the latent load is relatively high, the air must be cooled below its dew-point temperature, and sometimes rewarmed to return it to the comfort range. Refer to Chapter 43 for general information on the subject of controls and for ap plications relating to air-conditioning systems. REFRIGERATION PIPING The pressure drop which occurs during passage of the. refrigerant through connecting piping is similar in effect to that which occurs through suction and discharge valves of the compressor. Thus, the effect of the pressure drop in the suction line between evaporator and compressor requires that a lower pressure be maintained inside the compressor during suction than is maintained in the evaporator. Tbe pressure drop through the connecting piping between the compressor and condenser requires that a higher pressure be maintained inside the compressor during discharge than in the condenser. These losses result in a greater compres sion ratio, and therefore greater power requirements, as well as a lower volumetric efficiency and higher displace ment requirements. Pressure losses in the liquid line be tween condenser or receiver and the expansion valve may Refrigeration 559 Table 5 .... Dichlorodiftuoromethane* (CGiF*) liquid tines. Tons Capacity per 100 Ft Equivalent Length line Size, laches Pressure Drop per (00 Ft Eflw'rotenf leogtt, Pa 3 5 to 20 HOD HOD HIPS HOD H IFS H IPS HOD 0.88 2.89 4.86 4.86 9.73 9.73 10.5 1.14 3.64 6.81 6.81 12.6 12.6 14.1 1.80 5.56 10.2 10.2 18.5 18.5 21.8 2.58 8.50 15.8 15.8 27.0 27.0 33.0 1 IPS 1H OD 1H IPS lH OD 1H IPS 1H OD 21.4 21.4 36.9 36.9 62.0 62.0 28.2 28.2 48.1 48.1 80.2 80.2 41.3 41.3 70.5 . 70.5 114. 114. 60.8 60.8 101. 101. 160. 160. 2 IPS 2H IPS 3 IPS 3H IPS 4 IPS 124. 230. 364. 539. 753. 161. 297. 469. 704. 972. 231.. 426. 676. 1005. 1385. 328. 607. 972. 1430. 1945. Note: Toonace nlaea above thoae underlined give velocities of 200 fpm or *Re(riccAat IX ' result in some flashing of the liquid refrigerant, unless the liquid is subcooled. In all cases, friction losses should be kept to a minimum, and piping should be selected which will give the smallest loss consistent with overall economy in the system. - ____ Refrigerant liquid lines from the receiver to the expansion valve should preferably be designed with a pressure drop of less than 5 psi, and with 10 psi as the maximum. A velocity of 100 to 250 fpm is recommended to prevent a pressure drop great enough to cause vaporization of the refrigerant abead-of the expansion valve. If the evaporator is to be located at a higher elevation than tire condenser or receiver, account should be taken of the pressure drop for each foot of static liquid lift'. Approximate values are 0.26 psi per foot for ammonia, 0.57 psi per foot for di- chlorodifiuoTomethaae, 0.51 psi per foot for monochloro- difluoromethane, and 0.64 psi per foot for monofluorotri- chloromethane. Where there is a possibility of vaporization of some of the liquid before reaching the expansion valves, means for subcooling should be provided. Since a reduction of suction pressure at the compressor results in an appreciable reduction in capacity and more power input per ton of refrigeration, great care should be given to the proper sizing of suction lines between the evaporator and the compressor. Although comparatively high velocities, 500 to 5000 fpm, may be used, the optimum value will depend upon the refrigerant and the operating- pressure range. Since return of the oil to the compressor must be considered in the case of the fluormated hydro carbons and methyl chloride, for these refrigerants the minimum velocity should be 500 fpm for horizontal runs and 1000 fpm for vertical runs. For the former, the usual design velocities range between 1000 and 2000 fpm. Too Table 6 .. -. Maximum Tons of Compressor Capacity for . CQjFj tines* (Only for (mperotwni Mieobd) Section liras hated on JOS F Condamg Temperature | Discharge Indiei Psi Pressor* Drop per 100 Ft Equivalent lengtft at 40 F Saturation Condertseig Temperature t 2 3 4 5 tl5f 90 F M OD % IPS H OD H IPS 0.14 0.17 0.25 0.35 0.20 0.24 0.35 0.45 0.28 0.34 0.51 0.65 0.35 0.42 0-62 0.79 0.41 0.49 0.73 0.93 0.45 0.54 0.81 1.03 1.43 1.87 1.15 1.50 H OD H IPS 1H OD 1 IPS 0.55 0.68 1.26 1.43 0.76 0.94 1.80 2.01 1.L0 1.35 2.57 2.89 1.34 1.65 3.17 3.54 1.58 1.92 3.76 4.17 1.75 2.12 4.15 4.60 2.97 3.26 5-05 5.29 2.38 2.62 4.05 4.25 iH OD IX IPS lH OD lX IPS 2.21 2.70 3.40 4.05 3.12 3.82 4.78 5.75 4.45 5.37 6.79 8.10 5.50 6.72 8.42 10-12 6.38 7.6S 9.77 11.6 7.05 8.4f 10.8 12.8 7.72 6.19 9.16 7.35 10.92 8.75 12.5 10.0 2H OD 2 IPS 2H OD 2X IPS 6.12 8.60 12.1 7.66 10.6 15.3 12.0 17.1 24.0 12.0 17.1 24.0 15-1 19.2 30.1 30.1 17.4 32.2 34.6 34.6 19.2 24.5 38.2 38.2 19.2 20.6 32.2 32.2 15.3 16.5 25.9 25.9 3H OD 3 IPS m OD 3M IPS 19.1 20.9 27.8 30.2 27.2 29.4 39.7 43.2 38.2 42.3 55.7 61.0 47.8 51.8 69.8 76.1 55.0 60.0 80.3 87.0 60.7 66.2 88.7 96.0 51.5 54.5 72.0 78.8 39.8 43.8 57.6 63.3 4X OD 4 IPS 5 IPS 8 IPS 38.6 ' 40.7 71.3 126 55.2 58.6 100 183 78.0 83.0 141 257 97.3 103 176 322 111 118 203 366 123 130 224 403 95.8 77.1 101.6 81.6 171.5 137.8 266 214 8 IPS 211 10 IPS 352 12 IPS 550 297 422 523 602 664 461 370 503 712 887 1024 1130 725 582 780 1106 | 1373 j 1582 ; 1748 1041 836 13. high velocities create noise problems and excessive pressure drops. The total pressure drop in the suction line should be between one and two pm, if the velocity can be kept within the specified limits. Compressor discharge or hot gas lines may be designed with velocities from 1000 to 5000 fpm, except for dense gases such as carbon dioxide, where noise considerations will reduce the upper limit. A pressure drop of 2 to 4 psi is recommended for the discharge lines. Extensive tables are available in the literature for the determination of pressure drops through refrigerant lines with various refrigerants. The capacities listed in Tables 5, 6, and 7 are published in ARI Equipment Standards 520 (1946), of tire Air-Condi tioning and Refrigeration Institute, and are used by per mission. Table 5 shows the tonnage capacity normally allowed for CCLF, liquid lines per foot equivalent length of pipe, and Table 6, the maximum tonnage for suction 560 CHAPTER 38 1959 Guide Table 7.... Approximate Suction-tine Capacity Factors for Equal Pressure Drop of CG*F (Refrigerant 12) Saturated Suction Tanparature, F. 50 40' 30 20 10 0 -10 Factor.. 1.09 1.00 0.92 0.86 0.80 0.74 0.66 and discharge CCI*F, lines. Table 7 presents suctioa-Une capacity factors for equal pressure drop. ACCESSORIES Dehydrators, oil separators, strainers, vibration elimi nators, sight glasses, and various types of valves are ac cessories frequently needed for the proper installation and operation of refrigeration systems. Refrigerant-line de hydrators or dryers usually consist of copper containers fitted with tubing connections at either end, and contain a desiccant such as silica gel, activated alumina, or calcium chloride. The liquid refrigerant is circulated through the dryer during operation of the system, and the moisture content of the refrigerant charge is thus kept to a minimum. Oil separators are installed between the compressor and condenser to prevent excessive oil removal from the com pressor crankcase and its passage into the condenser and evaporator. The oil is separated from the gaseous refrig erant by gravity during its passage through a chamber of sufficient size to reduce the velocity. A float-operated valve maintains a mimim> oil level in the separator, and ad ditional oil is forced by pressure difference through, a line back to the crankcase. . Screen strainers are frequently installed in the liquid line piping before solenoid valves and expansion valves, as well as before regulating valves in water lines leading to water cooled condensers. Sight glasses that permit visual inspec tion of the condition of the refrigerant are sometimes in stalled on factory-assembled commercial unit systems. It is particularly advisable to place such a fitting before the expansion valve, if the evaporator is located above the condenser. - Flexible vibration eliminators, usually consisting of a bellows design covered with woven copper wire, are some times installed in copper lines where units such as com pressors are installed on flexible mountings, or where vi bration is otherwise a problem. Packed or packless shut-off valves are necessary where it may be required to isolate portions of a system. . EQUIPMENT CHARACTERISTICS AND SELECTION The various types of compression systems have quite different characteristics of capacity and power with varying evaporator and condenser temperatures, as may be noted from curves in figs. 16 and 17. From Fig. 16 it may be observed that power require ments for the centrifugal compressor increase much more rapidly than for the reciprocating compressor, with in crease in evaporator temperature. Similarly, the capacities of the steam ejector and centrifugal compressors increase more rapidly than those of the reciprocating compressor with increase in evaporator temperature. Thus, both the steam-jet and centrifugal machines tend to be more self regulating than the reciprocating. It is also evident from Fig. 16. that the steam-jet equipment is best suited for operation at high evaporator temperatures. - The effect of condenser temperature upon the power and capacity of the different types of compressors is shown in Fig. 17. It may be noted that the power required by the Refrigeration Machines at Constant Speed Fig. 17 .... Performance Characteristics of Compression Refrigeration Machines at. Constant Speed Refrigeration 561 Capacity Toot Table S.. .. Basis of Equipment Selection Majority Used Sea. Uteri F*w Uteri 0 to 10 Unit systems in conditioned space. Unit central systems using duct Built-up central systems. distribution. 10 to 25 Unit- central systems using duct Unit systems in conditioned space. Built-up central systems using re distribution. ciprocating compressors, adsorp tion, SQd absorption systems. 25 to 100 Built-up central systems using re Unit central systems using duet Central systems using adsorption ciprocating compressors. distribution. systems or centrifugal refrigera tion. 100 to 200 Built-up central systems using re Built-up central systems using ab Built-up central systems using steam ciprocating compressors. sorption and centrifugal com jet. pressors. 200 and Over Built-up central systems using cen Built-up central systems using Built-up central systems using re trifugal compressors- steam jet or absorption systems. ciprocating compressors. reciprocating compressor increases rapidly with increase in condenser temperature, while the power curve for the centrifugal compressor is relatively flat. It is also evident that the capacity of the steam-jet compressor is independent of condenser temperature until a certain point is reached, where it drops to zero. As previously stated, steam-jet equipment requires more condensing water than other types of compression systems. Consequently, steam-jet systems are well suited to those applications where condensing water is cheap, or where condensing water is rather high in temperature. - The selection of proper refrigeration equipment for any' air-conditioning job is of utmost importance for satisfactory " results. The most important factors in the selection of the equipment are: ' 1. Loads (as determined by the conditions of the space to be cooled). 2. Economics (both initial and operating costs). 3. Codes (local safety codes must be adhered to and in fluence the type of system to be used). A broad division of equipment to be used for a particular installation or application may be made on the basis of the magnitude of the load. Current general practice is outlined in Table 8. Unit of packaged systems, consisting of .a reciprocating compressor, condenser, evaporator, and fans, are generally used in the smaller sized jobs where electric power is avail able, as they are manufactured complete, ready to install, and are the moot economical (See Chapter 16). The reciprocating compressor in the built-up central sys tem (see Chapter 19) covers the widest range of application since it is applicable to either the direct-expansion or in direct systems, and can be driven by steam or gas engine, or by electric motors. The quantity of condensing cooling medium required is also less than for any other system, with the exception of the centrifugal compressor, which uses the same amount. Table 9 .... Typical Operating Conditions for Two Types of load Air Entering CoS Operating Batoaca ' Point Type of Load Ifu Sens&fo Endonn ' par Hr. to Total Hoot fP Rot. H%' EvopOrotor Con denser Pres f' sure Pti Sonibla Hoot % Restaurant Sensible 103.000 Latent . 45,000 Total 148.000 0.695 82 45 34.4 123 69.9 Office........... Sensible 121,000 Latent 27,000 Total 148,000 0.820 82 45 42.2 100 82.1 1 i j \ i Xr 1 562 CHAPTER 38 1959 Guide Centrifugal compressors are used for large installations, and usually where the indirect system is required. The driving mpTihanicm can be a steam turbine or electric motor. The steam-jet system is used where steam is available and cooling water can be had in large quantities. It will be noted by referring to Fig. 16 that all systems using compressors have a common characteristic, namely, that the capacity varies with the evaporating temperature. Not only can the equipment be selected to produce a given result, but the performance can be predicted under varying load conditions by the simple expedient of rising the vari able of evaporating temperature as the abscissa, and the load or capacity as the ordinate in a series of curves. Manufacturers of compressors and cooling coils furnish performance data for apparatus that can be {dotted in the form of curves similar to those shown in Fig. 18. The per formance of a compressor is plotted as a series of curves, each curve being drawn for a given condensing pressure. The performance of a direct-expansion coil at two different air velocities is plotted on the same graph. The operating point will be, of course, where the two curves cross. Data given in Table 9 illustrate two types of conditioned enclosures having tire same total load of 148,000 Btu per hour, but with two different ratios of sensible to total heat. In the case of the office with a ratio of 82 percent sensible to total heat, the operating point A in Fig. 18 is found to be 42.2 F evaporating temperature, with a face velocity of 500 fpm. In the case of the restaurant, with a ratio of 695 percent sensible to total heat, the air velocity is lowered to 300 fpm, and the evaporating temperature is towered to 34.4 F as shown in point B of Fig. 18. In order to obtain the same capacity, a larger condensing unit is used. This illustration assumes zero pressure drop through the suction line. The pressure drop can be taken into account by shifting the compressor performance curves by the amount of pressure drop expressed in Fahrenheit degrees. REFERENCES 1 P. C. Scofield: Air cycle refrigeration (Refrigerating En gineering, Vol. 57, June 1949, p. 558). * A. R. Mumford and A. A. Markson: Application and econ omy of steam jet refrigeration to air conditioning (ASHVE Transactions, Vol. 44, 1938, p. 33). * A. A. Berestneff: A new development in absorption re frigeration (,Refrigerating Engineering, Vol. 57, June 1949, p. BIBLIOGRAPHY Refrigerating Data Book, Vol. 1 (American Society of Re frigerating Engineers). H. J. Macintire: Refrigeration Engineering (John Wiley Sc - Sons, New York, 1937). N. R. Sparks: Theory of Mechanical Refrigeration (McGraw- Hill Book Co., New York). . B. F. Raber and F.'W. Hutchinson: Refrigeration and Air Conditioning Engineering (John Wiley 4c Sons, New York, 1945). J. A. Moyer and R. U. Fitts: Refrigeration (McGraw-Hill ' Book Co., New York). W. R. Haiosworth: Refrigerants and absorbents (Refrig erating Engineering, August, September 1944). B. H. Jennings and S- R. Lewis: Air Conditioning and Refrig eration (International'Textbook Company, Scranton, 1944). Jordan and Priester: Refrigeration and Air Conditioning (Prentice-Hall, Inc., New York, 1948). CHAPTER 39 THE HEAT PUMP History and Development; Basic Circuits; Fundamentals; Types; Heat Sources and Sinks; Performance Characteristics; Tem perature Levels; System Balance; Seasonal Performance; Annual Operating Cost; Components; Applica tion; Criteria for feasibility; Design and Selection; Systems for Larger Buildings; Sensible, Latent; and Low-Side Heat Storage THE term heat pump as applied to a year-round air History in the United States conditioning system, commonly denotes a system in Pioneering work on heat-pump development in the United which refrigeration equipment is used in such manner thatStates was conducted through the early 1930's mainly under heat is taken from a heat source and given up to the con sponsorship of a few investor-owned electric utility com ditioned space when heating service is wanted, and is re moved from the space and discharged to a heat sink when panies, with the objective of promoting wider use for their service. The wumnnkl character of electric load from sum cooling and dehumidification are desired. The thermal cycle' mer air conditioning, after a record of steady growth, was is identical with that of ordinary refrigeration, but the ap then already moving evident its likelihood of creating new plication is concerned alike with the cooling effect produced peak on utility systems. This prompted the in at the evaporator and with the heating effect produced at vestigation of methods whereby such load could be made the condenser. In some applications, both the heating and more favorable both to the customer and to the electric the cooling effects obtained in the cycle are employed simul company. taneously. The first major installation in the United States was made The heat-pump principle is also applied for purposes other about 1931, for a new 3,800,000 cu ft office building of than air conditioning, such as: supply of domestic hot water Southern California Edison Company in Los Angeles. Re in residences and commercial buildings, recovery of low- frigeration equipment of the already existing air-condition temperature beat as a useful byproduct in industrial opera ing system was modified to permit heat-pump operation tions, and disposal of heat from processes involving evapo with outdoor air in a conventional cooling tower serving as ration of water or other fluids at depressed temperature heat source. An installation made in Salem, New Jersey4 in and pressure. Defrosting of evaporator coils in refrigerating 1934 was thg first commercial heat pump in this country systems by intermittently admitting hot gas directly from HftsignM for complete heating and cooling. A number of the compressor is another application of the heat-pump buildings occupied by subsidiaries of American Gas and - method. Descriptions and diagrams of various beat-pump systems and criteria for feasibility are given later in this Electric Company in Ohio, West Virginia, Virginia, and Kentucky were equipped during the middle and late 1930's. chapter. The home office of Louisiana Power and Light Company at HISTORY AND DEVELOPMENT Algiers, Louisiana was equipped in 1936, using purchased city water as source of heat. An office building* of United Over a century ago, William Thomson (Lord Kelvin)1 sug Illuminating Company at'New Haven, Connecticut, erected gested the use of a compressor as a warming engine to heat in 1939, was equipped with a water-source beat pump. It buildings, as an alternate for combustion of fuels. Somewhat utilized as a standby beating system a large water storage prior to 1910 Dr. S. Z. Ferranti, Prof. J. Perry and Mr. T. ' tank equipped with immersion electric beating elements. V. Moriey, in England, strongly advocated the undertaking Throughout this early period all installations were custom of development in the design and application of heat.pumps, built, employing standard equipment components modified but the economic outlook, then unfavorable, deferred fur where necessary to suit the dual-purpose functions. After ther investigation. It was not until a paper on the principles World War II the use of heat pumps increased, particularly and economics of heat pumps, prepared in October 1928 by with the introduction of unitary equipment, in which the re T. G. N. Haldane, was presented before the British Institute - frigeration system, fans, pumps, and the necessary automatic of Electrical Engineers in December 1929,* that develop controls were assembled within a single housing. ment was started in the United States. Haldane reported the trial results from early installations made in Scotland. Ap plication for water heating was then as prominent abroad as use for space heating. Dr. A. R. Stevenson, Jr. was an early advocate in this In recognition of the status attained by heat pumps and their growing engineering importance, the American So ciety of Heating and Ventilating Engineers appointed a Technical Advisory Committee on the Heat Pump in 1947. country, having first presented the possibility to the Re An independent group from the electric utility industry, frigeration and Gas Committee of the American Gas Asso known as Joint A ETC-RET Heat Pump Committee, was ciation in April 1926, and later to the Franklin Institute.' founded in February 1947. This body has worked closely The concept held in this country today, that heat pumps with equipment manufacturers, giving advice on matters re for the large majority of space-heating applications should lated to suitability of equipment types and control methods, be regarded essentially as year-round air-conditioning de to experience resulting from trial installations, and espe vices, did not become generally accepted until about 1950. cially to the characteristics of electric loads. It has also under- ^ 563 564 CHAPTER 39 1959 Guide taken research projects in allied areas such as heat sources, utilization of solar energy as a supplementary heat source, and thermal storage methods. The Joint Committee has lent encouragement to publica tion of two textbooks*'* on the technology of heat pumps, and to the maintenance of a comprehensive bibliography,* a reference library, and installation statistics. Additional bibliographies and installation studies have been made by The Heat Pump Steering Committee of the Southeastern Electric Exchange.* The summer air-conditioning load has high electric power demand and.low annual load factor, and in addition, the highest <femar>r| peaks will occur on the relatively few ex . tremely hot days during summer months, when the load carrying capacity of the whole utility system (generation, transmission and distribution) is considerably lower than on cold days in winter. For example, the average .nnna.l load factor on a noncoinddental baas for summer air condition ing can be expected to remain between limits of 6 and 15 percent. This is far below the 64 percent present-day annual load [actor [or the total electric load of utility systems. Consequently, the large utility companies are giving sup port to the advancement of heat-pump technology as a means of broadening the field of application of the heat pump with its beneficial effect on the electric system load factor.1* Present Status Large central heat pumps of modem design, within the capacity range of about 100 to approximately 1000 horse power of compressor-motor rating, are now operating in a substantial number of buildings. Among noteworthy in stallations are those in the Oregonian Building and Equita ble Building, both in Portland, Oregon; Appalachian Elec tric Building in Roanoke, Virginia; Columbus and Southern Ohio Electric Building in Columbus, Ohio. Detailed informa tion on their design and performance has been presented in ASHAE papers"* " " and in technical magazines.1* In the Southdale Shopping Center in Minneapolis, Minn., a 700-ton heat pump installation with its associated deep wells providing the heat rink and heat source, has a coeffi cient of performance on the heating cycle of approximately 4. Internal combustion engine driven heat pumps in this installation have been found to provide additional heating capacity because of the recoverable heat in the wngiiw cool ing water and the muffler. . Compressor types employed in large central systems vary from one large centrifugal unit to as many as eight multi cylinder reciprocating units. A single or central system is generally used throughout the building, but in some instances the total capacity is divided among several separate heat- pump systems to facilitate zoning. Both weU water and air are used as heat sources. Compression is accomplished in two stages for a few recent projects. Frequently provision is made for heating and cooling service to be supplied si- - multaneousty to separate zones of the building. Unitary heat pumps, available from or under develop ment by many manufacturers, account for the large majority of residential and small commercial installations. Outdoor air is the heat source in the majority of installations, but models are built also for well water. Capacities cover the range from 2 to about 25 horsepower. Both hermetic and open-type compressors are used. The entire heat-pump cir cuit may be charged with refrigerant and sealed at the fac tory, or individual factory-sealed subassemblies may be connected together in the field. Some models are arranged for remote location of the outdoor-air heat exchanger that serves alternately as evaporator and as condenser. In ap pearance and dimensions, the of unit heat pumps closely resemble those of conventional air-conditioning units having equal capacity. The normal design basis is to select the size of compressor and motor for the summer cooling and dehumidification ca pacity requirement. For heating service with outdoor air as the heat source, supplementary electric resistance heat ing elements are normally provided for use during such periods of low temperature as may be required by the cli mate and heating load of the structure. These heaters are sometimes objectionable to the utility because the resulting seasonal electric consumption is low in comparison with the ' electric input demands they create on the electric service facilities. Consequently, it is important that the application engineer for such installations give careful attention to mini mizing the installed capacity of heating elements, as dis cussed later in this chapter. With unitary systems, defrosting of the evaporator coils at suitable intervals with minimnm interruption of heat supply to the building is usually accomplished automati cally by admitting hot refrigerant gas taken directly from the compressor discharge. Minimum industry performance standards of unitary heat pumps are covered by ARI Standard 240-57, Unitary Beat Pump Equipment, issued 1957 by Air-Conditioning and Re frigeration Institute. It applies to factory-made heat pumps and to matched assemblies as defined in the Standard, for residential, commercial and industrial service, but is not applicable to field-modified cooling units converted to heat- pump operation, nor to room air conditioners. The Stand ard provides that both heating and cooling capacity be ex pressed in Btu per hour under specific conditions, and in cludes minimum performance standards such as the ability to operate under maximum load conditions or adverse power and temperature conditions, and describes safety codes to which such equipment should be designed. It also outlines several performance requirements that are considered good practice in the design of either unitary heat pumps or built-up systems. ' Window-type, or in-the-wall type heat pumps, now in fac tory production in Vi to 2 hp size range, resemble conven tional units for summer air conditioning, similarly installed. Heretofore, capacity of these units on heating service has generally been less than needed in extremely cold weather to maintain the required temperature within the space served adequately by the same unit in summer. Except in regions having mild climate, they were useful principally for intermediate-season operation or to supplement the main heating system of the building. Some recently intro duced models, however, have characteristics more suited to complete year-round operation. As a result of more than a decade of experience gained in product development, factory production, field operation, and maintenance, heat pumps have become firmly estab lished throughout a large part of the country. Moreover, heat pumps are being adopted for entire housing develop ments. As many as 1500 units have been installed for a single project. The estimated number of central system heat-pump'units operating at the end of 1958 throughout the United States is approximately 40,000. Installations have been made in practically every state, with the southeastern, southwestern, and west coast states predominating. It is probable that at The Heat Pump 565 least two-thirds of total units take heat from outdoor air, and, of the remainder, nearly all use water, with ground coils almost ppgligihl* among the more recent installations. Ag gregate connected load may well reach 400,000 kilowatts. Approximately 150 domestic water heaters, mostly experi mental or pilot-type models, are in operation. BASIC CIRCUITS Fundamentals . Since, from the refrigeration standpoint, a heat pump is similar to a conventional refrigeration system, its baric cir cuit may be represented by Fig. 3 in Chapter 38. Changeover between heating and cooling services may be accomplished by: (a) actuating valves in the refrigerant lines, so as to interchange the positions of heat exchangers constituting the evaporator and the condenser, respectively, in the refriger ant flow circuit, or (6) by switching the paths of air, water, or other fluid that convey heat from source to evaporator and from condenser to sink, respectively. The interchange function inherent in heat-pump control led to use of the term reversed-cycle refrigeration during the early develop ment period of the heat pump, but tins inaccurate name is now obsolete. The operating principle of the heat-pump is identical with that of the heat-power thermodynamic cycle governing the conversion between heat energy and mechanical work. It is derived from the Second Law of Thermodynamics (see Definitions, Chapter 1). The operating efficiency, or coeffi cient of performance (CP), of an elementary perfect re frigeration system for both cooling and heating effects is given by Equations 2 and 3, Chapter 38. '" In actual systems, the coefficients of performance are de fined in the following terms: The heating coefficient of performance, (CP) *, of an in stalled heat pump may be defined as the ratio of the total instantaneous useful heating effect produced by the Heat- pump system at stated conditions, to the heat equivalent of the total energy input rate required to drive or operate the system. If total energy input of all auxiliaries such as fans and pumps is not included, it should be so stated. The coding coefficient of performance, (CP)c, of an in stalled heat pump.may be defined as the ratio of the in stantaneous useful refrigeration effect produced by the heat- pump system at stated conditions to the heat equivalent of the total energy input rate required to drive or operate the system. - The term performance factor, (PF), is simitar to coeffi cient of performance, but is used' when referring to values based on an extended period of time, such as a day, month, or season. The period of time covered should be given when tiring this term. If supplemental heat is involved, its effect should also be specified. Heat Pump Types Heat pumps for air-conditioning service may be classified according to (a) type of heat source and sink, (b) heating and cooling distribution fluid, (c) type of thermodynamic cycle, (d) type of building structure, and (e) size and con figuration. The more common types are shown in Table 1. The air-to-air^ type is the most common type of system. It is particularly suitable for factory-built unitary heat pumps and has received favorable acceptance for residential and commercial applications. The diagram shown in Table 1 is typical of the refrigeration circuit employed. In smaller uni tary heat pumps, it is common to replace the expansion and check valves with a capillary tube refrigerant control. A few installations have been made in which the forced-convection indoor heat-transfer surface has been replaced by a radiant panel. In air-to-air heat-pump systems, as shown in second dia gram of Table 1, the air circuits may be interchanged by means of dampers (motor-driven or operated manually) to obtain either heated or cooled air for the conditioned space. With this system one heat-exchanger coil is always the evaporator while the other is always the condenser. The conditioned air will pass over the evaporator during the cooling cycle .while the outdoor air will pass over the con denser. The change from cooling to heating is accomplished by portioning the dampers which may be motor driven or operated manually. A toater-to-air heat pump uses water as a heat source and gink and uses air to transmit heat to or from the conditioned space. Air-to-water heat pumps are commonly used in large buildings where zone control is necessary, and are also some times employed for the production of hot or cold water in industrial applications. Earth-to-air heat pumps may employ direct expansion of . the refrigerant in an embedded coil as illustrated in Table 1, or they may be of the indirect type described above under the water-to-air type. A water-to-water heat pump uses water as the heat source nrf wink for both cooling and heating operation. Heating cooling changeover may be accomplished in the refrigerant circuit, but in many cases, it is more convenient to perform the switching in the water circuits such as is illustrated in Table I. An earth-to-water heat pump (not shown in Table 1) may . be like the earth-to-air type shown except for the substitution of a refrigerant-water beat exchanger for the finned coil shown on the indoor ride. It may also take a form similar to the water-to-water system shown when a secondary-fluid ground coil is used. Some heat pumps which use earth as the heat source and sink are essentially of the water-to-air type. An antifreeze solution is pumped through a loop comprised of a pipe coil embedded in the earth and the chiller-condenser. Many variations are possible in the refrigeration circuit and in the heat-source and sink arrangements. Some of these are described in later sections of this chapter. Other types of heat pumps in addition to those listed in Table 1 are possible. An example is one which utilizes solar energy as a source of heat; its refrigerant circuit may re- ' semble the water-to-air, air-to-air, or other types depending on the form of solar collector and the means of heating and cooling distribution which is employed. Another variation is the use of more than one heat source. Some heat pumps have utilized air as the primary heat source, but are changed over to extract heat from water (eg. from a well or storage tank) during periods of peak load. The use of solar energy requires another heat source during periods of insufficient solar radiation. Industrial and Agricultural Heat Pumps While the principal use of heat pumps may always be in space heating and cooling, the heat-pump principle also has - applications in the industrial and agricultural fields, particu- - 566 CHAPTER 39 ALL. SINGLE STAGE COMPRESSION ' 1959 Guide The Heat Pump iarly in the process industries where large quantities of low temperature heat may be required. The heat-pump cycle, in many instance*, can be effective in the utilization of waste heat. - In a number of processes, low-temperature heating and moderate refrigeration are required simultaneously. The concentration of fruit juices may be accomplished by a beat-pump system. Fig. 1 illustrates the application of the heat-pump prin ciple for drying. A large portion of the heat given off from the condenser while heating the stream of dry air is re covered by the evaporator from both the sensible and la tent heat of the moisture-laden air downstream from the material being dried. This type of heat pump is expected to find particular application in the drying of tobacco and other agricultural products. Other Refrigeration Cydes Any thermodynamic cycle that is capable of producing a cooling effect may theoretically be used as a beat pump. Other than the ordinary vapor-compression cycle, possible cycles include (a) the heat-operated absorption cycle, (b) the ejector cycle, (e) gas cycles, both open and closed1* and (d) the thermoelectric cycle." None of these cycles as heat pumps is currently practica ble due to limitations in efficiency, cost or size. HEAT SOURCES AND SINKS Table 2 shows the principal madia being used with heat pumps as a heat source for heating and as a heat sink for cooling. The most practical choice for a particular applies tion will be influenced primarily by geographic location, climatic conditions, initial cost, availability, and type of structure. Various factors to be considered for each source are given in Table 2. A more detailed discussion of design and selection factors for each source and sink follows. Air Outdoor air offers a universal heat-source, beat-sink me dium for the heat pump. Extended-surface, forced-convec tion heat-transfer coils are normally employed to transfer the heat between the air and the refrigerant. Typically these surfaces are 50 to 100 percent larger than the corre sponding surface on the indoor side of heat pumps using air as the distributive medium. The volume of outdoor air handled is also usually greater in about the mum propor tions. The temperature difference during heating operation 567 between the outdoor air and the evaporating refrigerant generally is in the range of from 10 to 25 F deg. The performance of heating and cooling coils for air is given in more detail in Chapter 23. When ne-W-ting or designing an air-source heat pump, two factors particularly must be taken into consideration; (1) the variation in temperature experienced in a given locality and (2) the formation of frost. The determination of the heating design temperature for an air-source heat-pump installation is usually more critical than for fuel-fired heating systems because the heat pump capacity is generally more closely matched to the design requirement for heating. This results from the desire not to oversize the installation with respect to cooling because of the large heating requirements. Moreover, the decreased heating capacity of the air-source heat pump at low tem peratures establishes the balance -paint, i.e., the outdoor temperature at which the capacity matches the heat re quirement. When the surface temperature of an outdoor air coil is 32 F or lower, frost may form and if allowed to continue, will interfere with heat transfer. Research has shown that with a' pnrriinftl amount of frost deposit (typically about 2 to 3 lb per sq ft of coil face area) the heat transfer capacity of the coil is not substantially affected.1* The number of de frosting operations will be influenced by the climate, the air-coil design and hours of operation. Experience has shown that little defrosting is generally required below 20 F and below 60 percent relative humidity." This may be confirmed by psychrometric analysis using the principles given in Chapter 23- However, it should be noted that under very humid conditions when small suspended water droplets may be present in the air, the rate of frost deposit may be about three times as great as would be predicted from psychrometric theory. Under such conditions, a heat pump may re quire defrosting after as little as 20 minutes of operation. In applying an air-source heat pump, the effect of this con dition on loss of available beating capacity should be taken into account. Early application of air-source heat pumps followed com- . mercial refrigeration practice involving relatively wide fin spacing; (i.e., 4 to 5 fins per inch) on the theory that this would permit faster defrosting. However, experience has proved that with effective hot gas defrosting much closer fin spacing can be tolerated and obtains the advantage of a reduction in the size and bulk of the system. In- current practice a fin spacing of 8 to 10 per inch is widely used and some of the newer units have outdoor coils with as many as 13 fins per inch. ' Water , Water may represent a satisfactory, and in many cases an ideal, heat source subject to the considerations listed in Table 2. Well water in particular is attractive .from the standpoint of its relatively high and nearly constant tem perature, generally being about 50 F in northern areas and 60 F and higher in the south. Information on well water availability, temperature, and chemical and physical analysis is generally available from U. S. Geological Survey offices located in many major cities. , Surface or stream water may be utilized, but under winter conditions of reduced temperature, the cooling spread be tween inlet and outlet roust be limited to prevent freeze-^ip in the water chiller which is absorbing the heat. Some large heat-pump systems have been in operation in Europe where Table 2 . . . . 568 "O ao S'f S5 O J d>xo& S 3 .ai D 33 *. 5 O*3 g-2 >o. pH . oa'O g 2O O>*P 3-T3 C _ .2 g o iljs-sl .EeS ^O > CHAPTER 39 g.S Ex ffft* 3r,'8 | 3*1.5 g 'Efl Is f O Tirs.-g |.s > & = = s = l^-2 a " g*a =S. w2 *= 2 | a g-g -2* 1.9 s a a 1 <> 1959 Guide .O 5 - 4)--, " 225 ^5 2 9 a B e-Ur-a 1 s sJ-s l-sl-g-l? 5J II5!-5 w r: aa sS o a B>n * u |o Ia SPCi w^3 2s3 =.2o-S> 0.2 o Sa | BSo-S H e a t Pump H e a t Sources a n d Sinks *s |i | *3 11 c 5 if? ^ SSS I . XO a 11 ?& ao S`-Sw 'a 8 aa au > ~s-z te ca x *aS J - 56 2~ 3 S.5 S.W Is S'2- 1* H S*S-2.?| o |*o j? ss2^Q^gi^l-sa;5-gssg',:' s^|lf-l=:5S' ggl B-u.!*a "fi o'! lisle? J jt Ta5 qjo ga-o ab-S 'ii-pigg>lsUjLll w M g3 co 5^ 9'5j*,3 O.Sg 5 --" _ 0SSSa ag-I-S is* 3J eg 3*S I*3 S j a `"|o^^e9 H 2 _ I0S.2"g"5;gb_pE--5g 2a o ggj&a Moitg;Sj< ea > S8.S2 .3 . & *? * & w Sa 0.3s-ss QQ < 163! The Heat Pump 569 winter stream conditions around 35 F have permitted inlet- cutlet temperature spreads of only l or 2 deg. Under certain industrial circumstances, use may also be made of waste process water as a source, as for example spent warm water in laundries or warm condenser water from large industrial condensers, for specialized heat-pump operations. Utilization of water during cooling operation follows, in general, conventional practice with water-cooled condensers. Water-refrigerant heat exchangers generally take the form of direct-expansion water coolers either of the sheU-and-coii type or of the shell-and-tube type and are circuited to per mit usage as a refrigerant condenser during the heating cycle and as a refrigerant evaporator during, the cooling cycle. Further information on this type of equipment will be found in Chapter 38. Earth . Earth as a heat source and rink, by heat transfer through buried coils, has not been used extensively. This may be at tributed to high installation expense, ground area require ments, and the difficulty and uncertainty of predicting per formance. - Compositions of soil vary quite widely from wet clay to sandy soil, and have a predominant effect on thermal prop erties and attendant overall performance. The heat-transfer process in the soil is primarily one of bulk temperature change with time (e.g., transient heat flow). Thermal dif- juxivity a, the ratio of thermal conductivity to the product of unit density and specific heat, a = k/pc, is a dominant factor and is difficult to determine at different building sites. The moisture content likewise has an influence, since energy in the ground may also be transported via moisture travel in the soil. In general, earth coils, usually arranged to be spaced hori zontally at. from 3 to 6 ft, are submerged below the surface from 3 to 6 ft. Though a lower depth might be preferred, excavation cost requires a compromise. Mean undisturbed ground temperatures generally follow the mean annual cli matic temperature for any place. Many individual studies have been conducted to deter mine earth heat transfer with respect to heat-pump possi bilities, involving theoretical as well as practical considera tions (References 20 through 32). As mentioned in the section Heat Pump Types, two gen eral systems prevail for utilization of earth coils. The first is that of direct expansion of a refrigerant in a buried coil under winter beating conditions with refrigerant vapor con densation under summer conditions,' and the other is the transfer of heat between a liquid pumped through a buried coil and the earth (indirect system). The direct system in volves special provisions to insure the proper flow of liquid and vapor, that is, pitching downward to prevent trapping of liquid in pockets, etc. The indirect system is less sensitive since the liquid is pumped through the coils under regulated flow rates. The coil length required, as quoted by some authorities, is 200 to 400 ft of Ya- to lVi-in. pipe per ton of refrigeration for a coil buried at a depth of 4 ft with average pipe spacing 4 ft on centers. To insure continued contact of the coO with ground material, despite earth settling tendencies, the space directly around the coil is sometimes backfilled with sand. Solar Although still largely in the research stage, increasing in terest is being shown in solar energy as a heat source, either on a primary baas or in combination with other sources. The principal advantage of employing solar radiation as a heat-pump heat source is that, when available, it provides heat at a higher temperature level than other sources, thus resulting in an increase in coefficient of performance.0 As compared to a solar heating system without a heat pump, the collector efficiency and capacity are materially increased due to the lower collector temperature required. . Research and development in the solar-source heat-pump field has been concerned with two baric types of systems: direct and indirect. In the direct system refrigerant evapo rator tubes are embodied in a solar collector, usually of the flat-plate type. Research has shown that when the collector has do glass cover plates the same collector surface can also function to extract heat from the outdoor air* The same surface may then be employed as a condenser using outdoor air as a heat rink for cooling. The refrigeration circuit em ployed may resemble that shown in Table 1 for an air-to- air beat pump. . An indirect-type system employs another fluid, either water or air, which is circulated through the solar collector. When air is used, the first system shown in Table 1 for an air-to-air heat pump may be employed, the collector being added in such a way that : (1) the collector can serve as an outdoor-air preheater, (2) the outdoor-air loop can be closed so that all source heat is derived from the sun, or (3) the collector may be disconnected and the outdoor air used as the source or sink." When water is circulated through the collector, the heat-pump circuit may be of either the water- to-air or water-to-water type0 illustrated in Table 1. On all heat-pump systems employing solar energy as the only heat source, either an alternate heating system or a means of storing heat is required'during periods of insuffi cient solar radiation. Heat storage is discussed in a later section of this chapter. PERFORMANCE CHARACTERISTICS Temperature Levels ' Temperature differences are required to transfer heat from the heat source to the evaporating refrigerant of. a heat pump, and similarly from the condensing refrigerant to the hpating fluid. Hence the total temperature lift of the refrig eration system must be increased over that represented by the difference between the heat source and rink temperatures. fig. 2 illustrates typical temperature levels for both heat ing and cooling operation. Specific heat pumps may vary somewhat from the temperature levels shown depending on their design and specific conditions of operation. Equation 3 570 CHAPTER 39 1959 Guide Rg. 3 -... Variation of Coefficient of Performance with Temperature 4. Determine the condenser capacity from Q. = Q. 4- 3413 P. - Q,, (1) where Qt = condenser capacity, Btu per hour. Qt = compressor refrigeration effect (evaporator capacity), Btu per hour. Qt. heat loss from compressor, Btu per hour. (Q< may have to be approximated if unavailable from com pressor manufacturer. For many compressors Qca is negligible.) 5. Plot Qt obtained from Equation 1 on a chart similar to C of Fig. 4. (See Fig. 5.) 6. Select other condensing temperatures in combination with the original evaporator temperature from Step 1 and repeat Steps 2 to 5 as necessary to determine the condenser capacity at which the system balances. Points A and B on Fig. 5 repro of Chapter 38 defines the coefficient of performance (CP) of a Carnot cycle heat pump. Applying the relationships given with evaporator and condenser temperatures illus trated in Fig. 2 yields the coefficient of performance (CP) for a Carnot cycle heat pump shown in Fig. 3. An actual heat pump will, as a rough approximation, be about 50 per cent as efficient as a Carnot cycle heat pump and will have a coefficient of performance dependent on temperatures, as illustrated in Fig. 3. System Balance . The performance characteristics of a heat-pump system wui be predicted by evaluating and combining the per formance characteristics of its individual components.*1 Data available from component manufacturers may be portrayed as shown in Fig- 4. The conditions of system balance can be established by the following procedure: 1. Choose a combination of evaporator refrigerant tempera ture tr and condensing temperature t. 2. Determine the compresor refrigerating effect from per formance curves anriUr to A of Fig. 4. 3. Determine the compressor power input P, in kilowatts, from curves similar to B of Fig. 4. CVAR. TCR.%,,r 4A comrresso capacity 4C CONDENSER capacity (heat source temp) minus (cvap. tcmpJ t,-sr,r . 40 EVAPORATOR capacity Rg. 4 .... Performance Characteristics of Heat-Pump Components sent the results of these calculations. Two points will nor mally be sufficient to determine the balancing Q. . 7. Select other evaporator temperatures and repeat Steps 1-6 (See Fig. 5.) . 8. For each evaporator temperature find the corresponding heat source temperature t. from chart similar to D of Fig. 4. With the conditions of system balance found from the foregoing procedure, it is a relatively simple matter to es tablish the heating performance characteristics. The net. heating effect may consist only of the condenser heat, or, depending upon the system design, may also include heat losses from the compressor and motors, and the heating ef fect of a refrigerant subcooler coil. The cooling performance can be determined in a similar manner. For a heat pump which employs a constant temperature heat source, a few computations will generally establish the hftlajiffing conditions for tr and e. For a heat pump having source temperature subject to considerable variation (eg. air source), the balancing conditions for a wide range of tr will be necessary. Fig. 6 shows the performance characteristics of a typical heat pump determined either from actual system tests or The Heat Pump 571 Rg. 6 .... Operating Characteristics of Single-Stage Unmodulated Heat Pump from an analytical procedure such as already described. Also shown are the heating and cooling loads for a typical resi dence. The temperature at which the heat-pump capacity and the structure heat requirement are equal is referred to as the balance point. If the balance point is above the heat ing design temperature, ta, then supplemental heat will be required as denoted by the shaded area. Seasonal Performance Fig. 6 illustrates some of the basic factors important in evaluating seasonal power consumption. Following the prin ciples given in Chapter 37 the heating power consumption for any period of time may be estimated from F= 24HD " 3413(1. - ti)(PF) where P beating kilowatt hours H structure design beat loss, Btu/br. t.D degree days for specified period, outdoor temperature at which structure heat loss is sere (approximate indoor temperature when beat gain from other sources is small), Fahrenheit, - outdoor design temperature, Fahrenheit, (PF) - performance factor for specified period. For a heat pump with a constant heat-source temperature, the heating capacity will be essentially constant and the performance factor (PF) can be taken as the heating co efficient of performance (CP)A. For an air-source heat pump, with its varying heat source temperature, it is necessary to either break down the period of operation into relatively narrow temperature spans and to compute the power consumption in each, or, alternatively, to find the performance factor (PF) by weighted average of the different coefficient of performance (CP) and op erating hours that apply at various temperatures. In either case it is necessary to have data on the time distribution of outdoor-air temperatures. The number of hours that will apply within a given temperature range may be based on past weather data for a specific location. For example, such data are available for a number of cities broken down by month and time of day." However, where the required weather data are not available and when it is not necessary to break the heating season down into shorter periods, gen eralized data such as portrayed on Fig. 7 may be employed. Fig. 7 is based on an analysis of 114 weather stations in the United States from Reference 38, in which the heating- season days were correlated with the TAC design tempera tures. The TAC design temperatures shown in 1948 to 1958 editions of The Guide were suggested by the ASHAE Tech nical Advisory Committee on Weather Design Conditions. They were temperatures which were equalled or exceeded during 97)i percent of the hours in December, January, February, and March chiefly for airport stations. Maximum deviation for any single location from the averages portrayed is on the order of 5 deg at 70 F out door temperature and is due mainly to variations in summer climate. Since curves must pass through points representing the winter TAC design temperatures, their accuracy is best in the low-temperature range. The vertical scale gives the outdoor design temperatures for heating, as given in Chapter 12, which take into account the probabilities of oc currence. Reference 1 of Chapter 12 provides the correla tion of these design temperatures with the TAC tempera tures. | 10 Fig. 7 .... Annual Cumulative Winter Temperature Distribution in the U. S. - 572 CHAPTER 39 1959 Guide Table 3____ Number of Defrosts per Year* (100 Percent Running Time) CEmote (TAC1 -10 to 5 &-9 f-n 12-14 JS-17 IB-20 21-23 24-26 27-29 30-32 33-35 36-39 39-41 Normally dry Normally damp 475 450 400 375 350 300 250 200 175 150 100 75 50 800 750 700 625 575 500 425 350 300 225 175 125 100 * The fiftuee *iren mat be multiplied by the running-time retio lor the period eonsidered- Ertra power consumption allowance must be made where periodic defrosting of an air-source evaporator is required, and where supplemental heating is employed. The number of defrosting operations required per month or a complete heating season is difficult to evaluate ac curately. It will depend on the detailed design and control of the beat pump, the climate, and the hours of operation. Table 3 gives the range in annual number of defrosts that may be expected on typical small unitary heat pumps. To obtain,a total yearly operating cost, the energy con sumption for cooling must be added to that required for heating. Suggested procedures for calculating cooling en ergy consumption are given in Chapter 46 and 54. Annua! Operating Cost ' A tabulation such as is shown by Table 4 may be used for estimating the operating cost for commercial and in dustrial installations. It is necessary to know the monthly kilowatt electric demands and the corresponding kilowatt . hour consumption for the base electric lead, as well as for the heat pump or any other electric equipment, in order to apply the proper electric tariff. The base loads, shown as Columns 1, 2 and 3 of Table 4, may include lighting, ele vators, office machinery, exhaust and supply fans, circulating pumps, and similar items which are normally essential in a structure and are cot affected by a particular air-condition ing design. The heat-pump kilowatt demand, during the month, which is required to satisfy the net day and night heat loss or heat gain (whichever is the greater), can be obtained from manufacturers' data. These resulting kilo watt demands are multiplied by a coincident factor to ob tain the coincident demands, listed in Columns 4 and 7. These coincident demands can be added to the base load demands to obtain the total electric load in Column 10. The coincident factors can best be obtained from published data on similar installations. The procedure for finding the heating and cooling kilowatt hours, Columns 5, 6 and 8, has been previously described. For residential installations, a detailed monthly estimate generally is not justified unless a monthly demand type of rate is in effect. In making a power consumption estimate for unitary heat pumps, a detailed breakdown into periods less than a com plete season, or the breaking down into small temperature spans, is not ordinarily justified. Manufacturers of this type of equipment provide estimating procedures which are sim pler to use, yet are of sufficient accuracy for the purpose in tended. These methods usually consist' of an' empirical equation, tabular data, or plotted curves which combine the influences of the rize and thermal properties of the struc ture, the beating design temperature, the characteristics of the heat pump, and supplemental heat usage. HEAT-PUMP COMPONENTS For the most part, the components used in heat pumps and the practices followed bear a direct relation to the low temperature refrigeration art. This section will outline the major components used and point out characteristics or special considerations which apply to the heat-pump field. Compressors Reciprocating compressors are used more than any other type on systems in the general range of Vi to 100 tons, and frequently even larger. A brief description of this type of compressor is given in Chapter 38. For the most economical application, it is general practice to select the reciprocating compressor to provide the desired cooling capacity. The cooling capacity is the evaporator capacity and represents the ability of the compressor to pump refrigerant vapor between the existing temperature limits. When heating, the capacity of a particular compressor is the sum of the evapo rator capacity (i.e., heat-source coil capacity) plus the heat equivalent of the compressor work. . - Figs. 13, 14 and 15 in Chapter 38 shows the capacity and power characteristics of typical reciprocating compressors. A compressor normally employed for comfort cooling use will have a clearance volume (ratio of gas volume remaining in cylinder after compresion stroke to total swept-cylinder Table 4 .... Suggested Procedure for Computing the Operating Cost of Commercial and Industrial Heat-Pump System Ported Set* lead lighting end MucsUaneoui Cm* Saw Load Heat Pump Coinddenf demand Heal Coot Supplemental Residence Heating Iff Used) Tefal Healing and Coaling Total fleUric load Total Cod Kw KwH (1) 12) KwH (3) Kw ' KwH KwH Kw KwH (4) (5) (6) 17) 18) KwH 19) IT KwH (ID 02) June July May Fil in one ice tor eacb mon tb throu b May 1 The Heat Pump 573 volume) of about 5 percent. The capacity drop off at low evaporator temperatures corresponding to low heat-source temperatures is also evident. The drop off in power at low evaporator and condensing 'temperatures is also evident. If the-compressor has low clearance volume, say 2Yt per cent, thpn it is more suitable for low-temperature operation, and will provide, for example, about 15 percent greater re frigerating capacity at an evaporator temperature of O F and a condenser temperature of 110 F. However, this com pressor has somewhat more power demand under maximum cooling load conditions than does one of medium clearance. -It is obvious that more total heat capacity can be obtained at low outdoor temperatures by deliberately oversizing the compressor. The compressor is oversized in order to obtain more beating capacity so it is necessary to provide some type of capacity reduction to bring the cooling capacity into balance. This can be done by means of two-speed motor drives, cylinder cutouts, or other methods as described in Chapter 38. The disadvantage of this arrangement results from the fact that the greater number of operating hours that occur at the higher suction temperatures must then be served with the compressor in the unloaded condition which generally causes lower efficiency. Therefore, the annual op erating cost will tend to rise. It is also true that the addi tional first cost of the oversized compressor must be economi cally justified by the gain in heating capacity. One method proposed for increasing the heating output at low tempera tures involves the use of staged compression in which one compressor may pump from --20 F suction temperature to 40F condensing temperature and a second compressor com press the vapor from 40 F to 120 F. In such an arrangement it is possible to interconnect any two compressors so that they are in parallel, both pumping from say 45 F to 120 F at the normal cooling rating point, while at some predeter mined outdoor temperature on heating they are reconnected so that they pump in staged relationship. Fig. 8 shows the performance of such a pair of compressors _ for compressors of both medium and low clearance volume. It is apparent that at low suction temperatures the recon nection into a staged relationship does provide some added capacity. Also, it should be understood that the motor selec tion involved must be based upon the maximum loading con ditions for glimmer operation even though the low stage compressor has a greatly reduced power requirement under the heating condition. . Fig. 8 .... Comparison of Parallel and Staged Operation The coefficient of performance will be approximately the same whether they are coupled in parallel or compoundstaged at any set of operating conditions depending some what on the motor characteristics when lightly loaded. ' A rotary compressor has characteristics similar to a re ciprocating compressor except that it is by nature pos sessed of low clearance and high volumetric efficiency. From this standpoint it is well suited to heat-pump service, pro viding about 30 percent greater capacity at 0 F--110 F lift than a medium-clearance reciprocating compressor. How- ever, this characteristic tends also to increase the power de mand at the maximum cooling load conditions. At this time, reciprocating compressors are most widely used for heat pumps, with rotary compressors restricted to the first stage of a staged-compression system and not used during the cooling cycle. Heat Transfer Components Refrigerant-to-air and refrigerant-to-water heat exchang ers, as previously described in the section Heat Sources and Sinks, are similar to heat exchangers used in current air conditioning practice. A refrigerant subcooler coil may be employed either in conjunction with an indoor air coil, or, on systems with a ventilation air supply, to preheat ventila tion air. A substantial gain in capacity and coefficient of performance can result. Refrigeration Components Refrigerant piping, receivers, expansion devices and re frigeration accessories in heat pumps are usually the same as those used in other types of refrigeration and air-conditioning systems (see Chapter 38). A reversing valve is used to change the system from the cool ing to the heat operation. This change-over requires the use of a valve, or valves, in the refrigerant circuit,* except where the change is accomplished in fluid circuits external to the re frigerant circuit (see Table 1). Reversing valves are usually pilot-operated by means of solenoid valves which admit bead and suction pressures to move the operating elements. Expansion devices for controlling the refrigerant flow are normally thermostatic expansion valves as described in Chap ter 38. Special requirements may sometimes be presented. If the circuiting is so arranged that the refrigerant line upon' which the control bulb is placed can become the compressor discharge line, the resulting pressure developed in the power element of the valve may be excess ve, requiring the use of a special control charge or pressure-limiting element. When a thermostatic expansion valve is applied to an outdoor air coil, a special cross-charge is desirable to limit the superheat at low temperatures, and thereby obtain a better utilization of the coil. When mi expansion valve is attached to a coil that is operated as a condenser, a bypass with a check valve is normally provided as indicated in Table i. On fireall factory-built systems, capillary tubes arc nor mally used as expansion devices. While a single capillary tube on both heating and cooling is sometimes employed, better efficiency and performance can be obtained by using a more restrictive capillary tube for heating than for cooling. This may be accomplished by using two capillary tubes in either a series or parallel arrangement with a check valve to bypass one for cooling or to block one for heating, respectively. . On an air-source heat pump that must operate over a wide range of evaporating temperatures, a capillary tube will tend to pass refrigerant at an excessive rate at low back pressures, causing liquid floodback to the compressor. In some cases suction line accumulators or charge-control devices are employed to minimize this effect. 574 CHAPTER 39 1959 Guide A refrigerant receiver is commonly used, as in other types of refrigeration systems, to provide a storage place for liquid refrigerant. It is particularly useful in a heat pump in order to takft care of the unequal refrigerant requirements be tween heating and' cooling. Control Components Heat pump control systems and components are of the witm general type used in other types of heating and cooling equipment. Reference should be made to Chapter 43. Practically all. heat pumps for residential heating and cooling are controlled automatically from the temperature of the conditioned space. Room air thermostats are usually of the type that combine the control of both the.heating and cooling function, the selection of function either being accomplished automatically in response to air temperature or manually by a selector switch. When supplementary heat ers are employed, usually electric resistance heaters, it is common to control them with the second stage of a two- stage heating control. This restricts their usage to makeup of the difference between the heating requirement and the heat-pump capacity (see Fig. 6). To avoid unnecessary usage and excessive electrical demand, particularly when the thermostat setting is raised suddenly, it is customary to use one or more outdoor thermostats to limit the amount of resistance heat used at the higher outdoor temperatures. For information on electric resistance heaters see Chapter 17. In residential heat pump applications, night-set-back, common with fuel-fired systems, is not ordinarily employed because substantial excess capacity is required for warm-up and because possible operating cost savings, .if any, are deemed to be small - On the larger type systems, a proportional action type of control is sometimes used for controlling compressor and supplementary stages in steps. A variety of defrosting control schemes have been used to sense the need for defrosting air-source heat pumps and to initiate and terminate the defrost cycle- - A timer is sometimes used and set to cause defrosting at predetermined intervals for instance, about every two hours. After initiation of the defrost cycle defrosting can be ter minated either by the use of a control sensing the coil pres sure or a thermostat located so as to measure the tempera ture of the liquid refrigerant in the outdoor coil. When the temperature (or corresponding saturation pressure) of the liquid leaving the outdoor coil rises to about 40 F the com pletion of defrosting is assured. Termination of defrosting may also be obtained by use of a second time interval con trol. Another method of starting the defrost cycle is to use a pressure control which reacts to the air pressure drop across the coil. Under conditions of frost accumulation the air' flow will be reduced and the increased pressure drop across the coil will initiate the defrost cycle. Again the preferred method of terminating the defrost cycle is to use a refriger ant temperature control measuring the temperature of the liquid refrigerant in the coil. ' ' A third method for defrosting involves a temperature dif ferential control in which two temperature sensing elements are used; one responsive to the outdoor-air temperature and the other responsive to the temperature of the refriger ant in the coil. As frost accumulates, the differential between outdoor temperature and refrigerant temperature will in crease, causing a defrost cycle to be initiated. The system will be restored to operation when the refrigerant tempera ture in the coil reaches a specified temperature indicating that defrosting has been completed. When the outdoor-air temperature decreases, the differential between outdoor-air temperature and refrigerant temperature decreases, and the defrost cycle is initiated sooner, Other Components Supplementary resistance heaters, commonly used with many unitary type heat pumps may be incorporated either within the unit or external to it. They may take any of the forms discussed in Chapter 17. When installed in the dis tribution ductwork, they are frequently controlled to tem per the air during defrosting operation on units employing reverse-cycle defrost. APPLICATION Criteria for Feasibility Factors to be considered in determining the practicability of employing a heat pump include the following: 1. Presence of a cooling load. ' 2. Relative amounts of heating and cooling. 3. Availability of suitable heat source and sink. 4. Equipment requirements and installed cost. 5. Operating cost. . These criteria may be applied whether the equipment to be considered is of the factory-built, unitary type or the field- assembled type. In fact, an analysis of these factors, in addi tion to determining feasibility of the heat pump for a par ticular application, should also be useful for choosing the equipment type. ' Unless there is a need for cooling, heating with a heat pump is ordinarily not economically feasible. Under certain circumstances this may not be true, but usually a heat-pump system will have a higher first cost than a fuel-fired heating system. With the almost universal need for comfort cooling, par ticularly in commercial establishments, but also to an in creasing 'extent in residences, the feasibility of a beat pump becomes more favorable. Only a portion of the required equipment will then have to compete with a separate heat-' ing system. In fact, in large buildings, the existence of si multaneous heating and cooling loads in different zones for a large portion of the time is often uniquely suited to a heat- pump system. The relative amounts of heating and cooling required may greatly influence the first cost and the suitability of a heat pump. In the usual case the size of the beating load is the predominating factor, particularly with structures in colder climates having low internal heat gain. The application of insulation and adequate sealing against unwanted air infil tration reduces the ratio of the heating to cooling loads. The availability of a suitable heat source and sink gener ally involves making the optimum selection from the stand point of overall economics. Factors to be considered were presented earlier in this chapter in the section Heat Sources and Sinks. . The heat source selected will usually also serve as a heat sink. It should be recognized that in applications requiring heating and cooling in different zones simultaneously, the heat source or sink need only handle the net heat input or output of the system. ' The Heat Pump 575 To estimate the equipment requirements and installed cost it is necessary to make at least a tentative equipment selec tion. Before this can be done it will, first be necessary to de termine the heating and coding loads. For small structures this generally entails only the calculation of the peak heat ing and cooling loads. For larger buildings, a more detailed analysis may be required in order to take into account the loads at other than the design conditions, the time periods at which loads occur, ventilation schedule, variations in loads due to internal heat gains from lights, equipment and occu pancy, and simultaneous hating and cooling loads in dif-. ferent zones. It is implicit in a feasibility study of this kind that the objective is to obtain a comparison between the cost of a heat-pump system and a combination air-conditioning and fuel-fired heating system. Therefore, in order to estimate the first cost of both systems, a preliminary design and selection of each must be made. It does not necessarily follow that the system with the lowest first cost is the optimum choice. An increase of initial cost for any system may be justified by savings in operating cost or by other benefits derived. The principal factors to be taken into account in esti mating operating cost are given in the section Performance Characteristics. The application or feasibility study of a heat-pump system with regard to operating cost involves the comparison between it and alternative types of systems con sidered. Operating cost of fuel-fired systems may be esti mated by the procedures given in Chapter 37. Heating and Cooling Distribution The distribution of the heating and cooiing'effect from a heat-pump system is an important application consideration, particularly because of the relatively low temperatures in volved as compared to fuel-fired heating systems. In a commercial-type structure, any system of distribution which is satisfactory for cooling will generally be satisfactory for heating with a heat pump. Conversely, any system satis factory for heat distribution with a heat pump will be satisfactory for cooling, except, however, that panel sys tems will seldom have sufficient capacity to handle normal cooling loads satisfactorily. Heat distribution in the space can be accomplished by forced air at high, medium, or low pressures; primary air with induction units; individual'fan and coil units; a split system composed of forced air and panels; or panels alone. All these methods of heating, except panels alone, are as applicable to cooling as to heating. The distribution from the beat pump to space units can be by use of water or air. Quantities circulated, pipe or duct sizes, transfer units, and other characteristics of the dis tribution system will resemble very closely standard prac tice for cooling systems. Heating and cooling distribution in residential heat-pump systems generally follows the same principles as for sum mer cooling. Refer to Chapter 46. It has been found with residential air distribution systems, comfort may be achieved with the air volumes and temperatures encountered with heat pumps when proper attention is given to the number and location of air outlets." Design and Selection Irrespective of the size and type of building and whether unitary or field-erected equipment is being considered, the first steps that should be performed are those described under Criteria for Feasibility. In applying unitary heat pumps, the manufacturers of these units ordinarily provide sufficient data and instructions for proper application. The typical procedure followed for both unitary and field-erected heat pumps is outlined below: ` 1. Determine heating and cooling loads. It is desirable also to determine the amount that loads may be reduced by addi tional insulation, sealing, and shading. Savings effected in equipment due to distribution and to operating costs may more offset the added-cost involved. In larger buildings, loads should be determined for the different conditions of operation including simultaneous heating and cooling. . 2. V-gtahlish heat source and sink. See previous section on thin subject. ' , 3. Determine type of distribution system. 4. Choose major components: compressors, heat exchangers, and air handlers. For unitary equipment, establish equipment size, type, and make. 5. Establish design of refrigeration system. 6. Choose auxiliary equipment: fans, pumps, valves, etc. 7. Determine equipment location. Since the heat pump operates without fuel and combustion products, considerable flexibility is permitted in its location. A single-package unit, may be located in a basement, crawl space, attic, roof, garage, or carport, in the conditioned space, or out-of-doors. For re mote-type, or split units, one section is generally located out doors and the other in a convenient indoor location. Consider able flexibility in locating equipment of a field-erected heat pump in one or more areas is possible. Factors to be considered in equipment location are: (a) Ac cessibility to heat source'and rank, (6) Convenient location with respect to indoor distribution system, usually duct work, (c) Availability of condensate drain, (d) Required accessibility and sufficient space for servicing, (e) Convenience to electric power wiring, (/) Suitability of structure foi supporting weight of equipment, (?) Effect of noise and vibration transmission, and (A) Appearance. ' 8. Determine control system and components. 9. Estimate first cost and operating cost. Illustrative Systems for Larger Buildings Fig. 9 shows a system employing well water as a beat source and sink. In this particular case a heat exchanger is used between the well water circuit and the fluid circuit to transmit heat to the heat pump, heat exchangers, and the indoor conditioning coils. Although this requires, an extra step of heat exchange, it avoids the necessity for pumping well water throughout the building and permits a high rate of flow in the building water circuit with resulting improve ment in heat transfer. The use of a water preconditioning coil as shown to preheat, or precool, ventilation air often reduces the size of refrigeration capacity required as well as the cost of operation. It should be noted that both heated and cooled water can be furnished simultaneously to indoor- air-handling or remote-room units as may be required by the existence of heating and cooling loads in different zones at the same time. - Fig. 10 illustrates an air-to-air heat pump system which is similarly suited to a structure having simultaneous heat ing and cooling loads. The refrigeration subcooling surface shown is used to preheat ventilation air and thereby effect substantia! economies in equipment size and operating cost. HEAT STORAGE The use of thermal storage in a heat-pump system can improve its performance characteristics. Installations of heat pumps with thermal storage have been made principally in a few large building systems."' " ** . All materials possess the property of thermal storage in 576 CHAPTER 39 1959 Guide greater or lesser degree. In the case of a building, the struc tural materials are almost always in the process either of absorbing heat from or delivering heat to the interior space. This effect is more pronounced in cooling operation where greater air temperature variation is tolerated. Storage tends to reduce the rate of temperature change and helps in some measure to reduce the peak equipment requirements. In this sense every heating and cooling system, can be said to in volve heat storage in some degree. Many attempts have been made, particularly in recent years, to increase the heat^sfcorage effect by using special heat-storage materials as part of the heating or cooling sys- Table 5____ Properties of Various Specific Heat Type Storage Materials Material Specific Heat Btv per (lb) (cv ft) (F deg) Density fb/cu ft Heat Capacity Btv per leu ft) (Fde) Water Iron Concrete Brick Gravel 1.00 0.11 0.27 0.20 0.20 62.4 490.0 140.0 120.0 100.0 62.4 53.9 37.8 24.0 20.0 Refrigerant want not shown Fig. 9 .... Row Diagram of Central-Type Heat-Pump System heating; or on the low side as an intermittent heat source at temperatures lower the heated space. Sensible Heat Storage Water, with the highest sensible heat storage capacity on a weight baas, is an obvious first choice and has the ad vantage of low cost, easy storage, and' good heat exchange properties. The danger of freezing can be reduced by various types of antifreeze solutions. In some cases, however, freez ing may be desirable. The maximum temperature is limited by the cost of maintaining water under pressures when over 212 F, but this temperature is high enough for most heat ing systems. Rock and gravel beds have also been employed, and have a heat content per unit volume approximately 20 percent of the value for water. The earth has been utilized for heat storage, both for heating and cooling in a number of instances. A problem with most solid media such as these is one of heat transfer into and out of the medium. Table 5 lists the thermal properties of some of the com mon materials used, or considered, for sensible-beat storage. Latent-Heat Storage Systems Because of the relatively large volumes required for all ' sensible-heat storage systems, many attempts have been made to utilize the latent beat of fusion of certain materials. Mod: materials have some capacity to absorb heat when changing from a solid to a liquid, and some materials have a large capacity to do so. Ordinary ice changing to water is a prime example of this kind and the possibility exists of utilising it as low-side storage. For most heating applications. tem. The result is to reduce the size of the heating or cooling equipment necessary to take care of peak demands. In the case of the heat pump, a provision for heat storage can serve not only to reduce the size of the heat pump neces sary for a given load, but also to provide a more desirable electrical load by shifting part of the load to the time of day when the cost of power is least. The off-peak electric hot water heater is a common example of such a heat-storage application. In general, there are two types of heat-storage systems that have been employed: (1) sensible heat-storage systems and (2) latent heat-storage systems. Usually the latter is . actually a combination of the two, making use of some sensi ble heat storage in addition to the latent effect. Heat storage in a heat-pump system may be utilized on the high side, when heat is available at a temperature suitable-for direct Fig. 10 .... Row Diagram of Air-to-Air Heat Pump for Simultaneous Heating and Cooling The Heat Pump 577 Table 6 .... Moteriab for neat Storage Listed According to Latent Heat per Unit Volume* of All Materials Having Melting Points between 72 F and 176 F, Listed in Chemical Handbooks Material Melting Point Heat Content G-cat per 9 / Specific Gravity lolenf Heat of Fmjoc per (/nil Volume (Tbeoteiicof) Thousand* of G-cal per as 6fg/a> ft Nitrogen pentoxide ' Gallium Sodium phosphate, dodecahydrate Sodium sulfate, decahydrate Water Nickel nitrate Calcium chloride Osmium tetroxide Zinc nitrate Calcium nitrate NA Ga NatHPOJ2HjO NajSOJOHjO H0 Ni(NOi)*6HjO CaClj6HiO OsO< ZnfNOOrfHjO Ca(NO)*4H0 Mi,v materials having point* between 7J and 178 F listed terials listed in 1 handbooks. 85 76.7 ` 1.63 125.0 14.0- 86 19.0 5.88 113.8 12.7- 94 66.8 1.52 101.5 11.4 90 57.1 1.46 83.4 9.4 32 79.1 1.00 80.0 9.0 132 36.4 2.05 74.7 8.4 86 40.7 1.68 68.4 7.7. 104 13.5 4.91 66.3 7.5 ' 98 31.1 2.06 64.3 7.2 108 33.9 1.82 61.7 6.9 to Intent heat of fusion. Selected as hjgbeat on a list of 100 organic and inorganic ma however, the temperature of this change is too low to be useful. Prolonged searches have been made for materials which pass through a change of state as reliably and regularly as ice and water, but at temperatures high enough to be used for direct application to space heating. In order to be much superior to water, the latent heat capacity of such materials must be high Most organic materials are eliminated from consideration on this haris alone. Furthermore, the absorp tion and release of heat must occur in predictable fashion. Many materials which have been tried exhibit the defect of subcooling, delayed change of state, or decomposition through time and repeated cycles. A study of all materials, both inor ganic and organic, listed in chemical handbooks resulted in a list of over 100 materials having a fusion temperature be tween 72 F and 176 F. Most of these materials are extremely unpromising as heat storage media because of cost, corro siveness, instability, or unavailability. For many of them, data on their heat of fusion are unavailable. All of these materials, where such data are available, have been listed in order of heat capacity per unit volume. Table 6 gives the nine materials which were highest on this list, and it is in teresting to note that there are few common or low cost materials among this group. Others, notably the first two, are academic curiosities. . * The material disodium phosphate is high on the list and has been used in a number of experimental installations. Re sults for the most part indicated a considerable unreliability at least in the particular form of the material which was used. Such factors as the rate of heat addition or release, rise and shape of container, presence of nucleating media, and temperature gradients proved important in determining the percentage of heat storage actually available compared with the theoretical. In several small house heating installa tions employing heat pumps with condenser-side storage, the amount of disodium phosphate actually used was 3300 lb with theoretical latent heat storage capacity of 400,000 Btu. Indications were that the material was only partially ef fective in actual heat-storage performance. A method which makes use of a mixture of this material suspended in oil has been successfully tested in the laboratory, and through use of forced circulation of the oil, has exhibited high rates of heat transfer. Low-Side Storage With a heat-pump system the possibility also exists of storing heat at relatively low temperature on the low side (heat source side) of the system. The freezing of water- has already been mentioned as one possibility. Heat pumps with solar energy as the heat source have been studied with.low- side storage.** . A limitation present with this type of storage system as compared to high-side storage is that the peak heating ca pacity of the system is limited to the heat-pump capacity when operating with the low-temperature storage reservoir as the heat source. In many structures, particularly in colder rlimAtes where the benefits of heat storage are potentially greatest, this is less than the peak heating load. REFERENCES 1 William Thomson: On the economy of heating and cooling of buildings by means of currents of air (Glasgow Phil. Soc. Ptoc., Vo!. 3, t)ecembcr 1852). . *T. G. N. Haldane: The heat pump--an economical method of producing low-grade heat from electricity - (Journal of Institulion of Electrical Engineers, London, June 1930). *A. R. Stevenson, Jr.: Refrigeration (Journal Franklin In stitute, Vo!. 208, August 1929). 4 Philip Spom and D. W. McLenegan: An all electric heating cooling and air conditioning system (ASHVB Journal Section, Heating, Piping and Air Conditioning, August 1935). `Experience with a reveraed-cycle heating system (Power, August 1941). * Philip Spom, E. R. Ambrose, and Theodore Bannister: Heat Pumps (John Wiley & Sons, New York, 1947). * E. N. Kemler and Sabert Oglesby, Jr.: Heat Pump Appli cations (McGraw-Hill Book Co., New York, 1950).. * Bibliography of the Heat Pump through J951 (Edison Elec tric Institute Publication No. 53-4). *Heat Pump Bibliography (compiled by Southern Research Institute for Southeastern Electric Exchange). "Philip Spom: Electric Heating and Year-Round Air Con ditioning and the Heat Pump (Edison Electric Institute Bulle tin, May 1955). n 578 CHAPTER 39 1959 Guide nJ. D. Kroeker and R. C. Chewning: Heat, pump in an building (ASHVE Transactions, Vol. 54, 1948, p 221). . "J. D. Kroeker, J. H. Bonebrake, and J. A. Melvin: Heat pump application to a newspaper plant (ASHVE Transactions, Vol. 57, 1951, p. 467). "Philip Sporo and E. R. Ambrose: Two-year performance of a heat pump system furnishing year-round air conditioning in modern omoe building (ASHVE Transactions, Vol. 57, 1951, p. 483). "J. D. Kroeker and R. C. Chewning: Costs of operating the beat pump in the Equitable building (ASHVE Transactions, Vol. 60, 1954, p. 157). "E. G. Hellyr and H. C. Weingartner: Methods of frozen juice concentration (Refrigerating Engineering, July 1950, p. 673). "T. F,Thomas: The air cycle heat pump (Engineer, August 22, 1947, p. 180; August 29, 1947, p. 206). " W. F. Friend: Future electronic, solar, and nuclear devel opments (ASHAE Transactions, Vol. 62, 1956, p. 563). " W. F. Stoecker: How frost formation on coils affect re frigeration systems (Refrigerating Engineering, February 1957, p. 42). " Heat Rump Electricity Usages and Other Operating Char acteristic* as Experienced under Various Weather Conditions (Southern Research Institute Report No. 2371-28S-SV11I, July 22, 1955). " L. R. Ingersoll and H. J. Plass: Theory of the ground pipe heat source for the heat pump (ASHVE Transactions, Vol. 54, 1948, p. 339).. . fiE. W. Guernsey, P. L. Bet*, and N. H. Skau: Earth as a beat source or storage medium for the heat pump (ASHVE Transactions,. Vol. 55, 1949, p. 321). " A. B. Algren: Ground temperatures as affected by weather conditions (ASHVE Transactions, Vol. 55, 1949, p. 363). 0 G. S. Smith and Thomas Yamanchi; Thermal conductivity of soils for design of heat pump installations (ASHVE Trans actions, Vol. 56, 1950, p. 355). "L. R. Ingersoll, F. T. Adler, H. J. Plass, and A. C. Ingersoll: Theory of earth heat exchangers for the heat pump (ASHVE Transactions, Vol. 57, 1951, p. 167). 0 G. 8. Smith: Factors useful in ground grid design for heat pumps (ASHVE Transactions, Vol. 57, 1951, p. 189). 0 Meri Baker: Design and performance of a residential earth heat pump (ASHVE Transactions, Vol. 59, 1953, p- 371). 0 W. A. Hadley and Raymond Eisenstadt: Moisture move ment in soils due to temperature difference (ASHVE Trans actions, VoL 59, 1953, p. 395). *G. S. Smith: Intermittent ground grids for heat pumps (ASHAE Transactions, Vol. 63, 1956, p. 473). 0 W. A. Hadley: Operating Characteristics of Heat Pump Ground Coils (Edison Electric Institute Bulletin, Vol. 17, De cember 1949, p. 457). . "Joint AEIC-EEI Heat Pump Committee*. Research fiesulls Concerning Earth as a Heat Source or Sink (Edison Elec tric Institute Bulletin, September 1953). "D, M. Vesta] and B. J. Fluker: Earth as heat source and sink for heat pumps (ASHAE Transactions, Vol. 63, 1957, p. 41). "D. M. Vestal, Jr. and B. J. Fluker: A Proposed Procedure for the Design of a Heat Pump Buried Coil (Texas A <k M Bulletin). 0 R. C. Jordan and J. L. Threlkeld: Availability and utilisa tion of solar energy (ASHVE Transactions, Vol 60, 1954, p. 177). "Philip Spam and E. R. Ambrose: The heat pump and solar energy (Association for Applied Solar Energy, Proceed ings World Symposium on Applied Solar Energy, November 1955). "C. P. Davies, Jr. and R. I. Lipper: Sun energy assistance - for air-type heat pumps (ASHAE Transactions, Vol. 64, 1958). F. I. Bridgers, D. D. Paxton, and R. W. Haines: Per formance of a solar heated office building (ASHAE Transac tions, Vol. 64, 1958). 0 F. R. EUenberger, A. B. Hubbard, W. R. Foote, F. Burg- graf, and J. J. Martin, Jr.: Evaluating heat pump performance (ASHVE Transactions, Vol. 56, 1950, p. 87). 0 U. S. Weather Bureau Forms E-l-D, E-4-D, E-6-D (U. S. Department o! Commerce). . 0 Alfred Koestel and G. L. Tuve: Performance end evalua tion of room air distribution systems (ASHAE Transactions, Vol. 61, 1955, p. 533). " Philip Spom and E. R. Ambrose: Heat pump system using water storage (Mechanical Engineering, Vol. 69, November 1947, p. 899). . 0 Philip Sporo and E. R. Ambrose: The beat pump, an all electric year-round air conditioning system (Heating and Venti lating, January 1944, p. 68). "T. L. Etherington: A dynamic heat storage system'(ASHAE Transactions, VoL 64, 1958). BIBLIOGRAPHY W. E. Johnson: Economic and technical aspects of the heat pump (ASHVE Transactions, Vol. 54, 1948, p. 201). J. D. Kroeker, R. C. Chewning, and C- E. Graham: Heat pump results in Equitable building (ASHVE Transactions, Vol. 55, 1949, p. 345). * J. F. Sandfort: Thermodynamic criteria for heat pump per formance (ASHVE Transactions, Vol. 55, 1949, p. 363). G. S. Smith: Climatology as an aid in heat pump design (ASHVE Transactions, Vol. 57, 1951, p. 499). C. F. Kayan: Electrical analogger application to the heat pump process (ASHVE Transactions, Vol. 59, 1953, p. 361). W. F. Stoecker: How frost formation on coils affects re frigeration systems (Refrigerating Engineering, February 1957, p. 42). ' Applied Solar .Energy Research (Stanford Research Insti tute, 1955--contains numerous heat pump references). Heat Pump Data Sheets on Residential and Commercial Installations (Edison Electric Institute Publication No. 56-12). CHAPTER 40 EVAPORATIVE APPARATUS FOR HEAT REJECTION Wofer Cooling Methods, Water Use and Conservation, Rivers and lakes, Spray Ponds, Atmospheric and Mechanical Draft Towers, Cooling Tower Theory, Design Conditions, Selection and Evaluation, Tower location, Operation and Maintenance, Evaporative Condensers REFRIGERATING systems and many other industrial air. The temperature gradient of a lake will vary with the processes generate heat that must be removed and dis season of the year. Applying a heat load will raise the average sipated. Small quantities of heat can be rejected directly towater temperature and decrease the temperature gradient the atmosphere by convection and radiation. When large from the surface to the bottom although stratification will quantities are involved, the most effective procedure is to remain. The cold water intake should, logically, be located transfer the beat to cooling water flowing through a heat ex as far below the surface of the water as practicable, and re . changer.1 The water, if cheap and plentiful, may be wasted mote from the hot water return to prevent bypassing. Dikes to a sewer or open waterway such as a stream or lake. The or piers have been built into lakes to prevent bypassing where source of the cooling water may be wells, a public water sys cold water intakes are adjacent to hot water returns, but tem, or a lake or river. they offer little advantage unless they extend into a lake for a distance of at least 300 ft. WATER COOLING METHODS Warm water discharged near the surface spreads out as a thin film. The temperature near the surface of a cooling pond Water Use and Conservation will average about 4 F deg above the bottom temperature. A The rapidly expanding demand for water is depleting what was once looked upon as an inexhaustible natural resource. The water table is receding in most localities. Communities are finding their present water systems inadequate to supply the increasing demands of domestic and industrial users. Heavy industrialisation- along flowing streams causes pollu tion. The temperature of the water that may be discharged into the stream is frequently limited in order to protect wild life. Many cities do not have adequate sanitary or storm sewers to handle cooling water. As a result of the increasing suction pipe located at the bottom of the pond will not with draw water at the temperature of the lowest stratum. A hydraulic gradient is set up which withdraws water from all strata, and the intake temperature will be about 2 F deg be low the surface temperature. The heat dissipation is a func tion of wind velocity and the temperature difference between water surface and the dry-buib temperature. Fig. 1 is a typi cal performance chart for lake cooling, with wind velocity measured 5 ft above water level. Throne1 has developed ad ditional charts for other conditions. The heat dissipation of a demand and the lack of an adequate supply or disposal sys tem, users are being forced to conserve water by using recircu lating systems. Heat must be removed from the circulating water by some type of water cooling apparatus. Rivers and Lakes Plants located on flowing streams can use a once-tbrough system, discharging the heated water downstream from the intake to prevent mixing. Intake screens and sometimes set tlingbasins, are needed to remove debris. The intake structure must be designed to handle flow conditions varying from flood stage to the minimum flow during periods of drought. The operation can be hampered during cold weather by ice clogging of the intake or by ice jams restricting the flow of the stream. Since water treatment is seldom economical, scale and corro sion may be a problem. Intermittent chlorination may be used, however, to control the growth of slime and algae on heat exchanger surfaces. If the stream temperature becomes too high, it may be necessary to cool the effluent before dis charging it into the stream. Lakes or ponds may also be used as a source of cooling water.* The water temperature in lakes or streams tends to follow the average dry-bulb temperature of the surrounding 579 Fig. I .... Performance Chart for Lake Cooling 580 CHAPTER 40 1959 Guide lake increases from 0 to 10 Btu per (sq ft) (hr) (F deg temperature difference) of air and lake water surface, for duty up to 150 Btu per (sq ft) (hr) and wind velocities up to 6 mph with air temperatures varying from 20 to 80 F. Spray Ponds . Heat is dissipated from the surface of a lake by evaporation, radiation, and convection. The spray pond divides the water into small drops, greatly extending the water surface, and brings it into intimate contact with the air.1 The heat trans fer is largely due to evaporative cooling as explained in the section Cooling Tower Theory. The driving force is the dif ference in enthalpy rather than temperature difference. The water temperature tends to approach the wet-buib rather than the dry-bulb temperature of the air. This offers an in herent advantage in making it possible to cool the water to a temperature lower than the dry-buib. - Cooling occurs in a spray pond as the water is propelled upward and then falls to the surface of the pond. The pond itself acts largely as a collecting basin. A typical nozzle ar rangement is shown in Fig. 2. The design criteria in Table 1 provide a guide that can be used in laying out a pond. Table 1-------Spray Pond Design Data Coorantioooi Up-Spray System Units Stondord Mm Max Water capacity per nozzle. Nozzles per 12 ft length of Pipe....................................... Height of nozzles above water level.......................... Nozzle pressure.......1............. Size of nozzles and nozzle arms............... ...................... Distance between spray lat- eral piping.......................... Distance nozzles from pond side unfenced..................... Distance nozzles from pond side fenced.......................... Height of louver fence......... Depth pond basin................. Friction loss allowed per 100 ft pipe................................. Design wind velocity........... gpm 35 to 50 25 64 ft psig . 6 6 5 5 in. 2 IX ft 25 13 ft 25 to 35 20 ft 15 to 20 15 ft 12 12 ft 4 to 5 2 ft mph 1 to 3 5 -- 3 GO 6 12 7 2 38 50 25 12 -- -- -- A reasonably accurate estimate of spray pond performance can be based on the outgoing wet-bulb temperature of the air passing through the filled volume. This temperature, obvi ously, cannot exceed the hot water temperature. It can ap- proach the hot water temperature if it passes lengthwise through a long spray pond, but will have a small temperature rise when passing broadside through a narrow pond. The values in Table 2 can be used to obtain a reasonably accurate estimate of the cold water temperature with respect to the calculated outgoing wet-bulb temperature. Wind-passing through a pond-carries away entrained water as drift. This creates a nuisance in the area on the leeward The wind varies constantly in both direction and velocity. The wet-bulb temperature is usually changing also. These variations result in a continually changing temperature of the water as it strikes the surface of the pond. The pond acts as a reservoir so that the water temperature at the suction of the pump represents an average of past operating conditions. These characteristics maka it difficult to test a spray pond or to develop ratings. As a result, spray ponds are not used when water temperatures must meet narrow limitations. They are usually designed for a 10 to 15 F deg cooling range and about a 10 deg approach of cold water temperature to the'wet-bulb temperature. The water leaving a spray nozzle will rise to a height of approximately 1 ft per psi of nozzle pressure. It will strike the surface of the pond in a circular pattern having a radius of about 10 ft. The cooling occurs within an activefilled volume having a height equal to the elevation of the nozzles above the surface plus 1 ft per psi nozzle pressure, and a plan area ex tending 10 ft beyond the outer nozzles. The heat is trans ferred to the quantity of air passing through the air area which is the projected area of a vertical plane through the active filled volume and broadside to the direction of -the air movement. The length of air travel is the horizontal distance the air moves through the filled volume. Table-2 .... Degree Adjustments to be Applied to Leaving Air Wet-Bulb Temperature to Find Cooled Water Temperatures of Spray Ponds* Coating Sang* F deg Entering . WV-Bufl>b ramp. F Adjustment in F Degree* lertgft of Ah Travel (Fee#) 100 50 25 10 80 WB -3 +2 +4 70 WB -2 +3 +5 60 WB -1.5 +3.5 +5.6 15 80 WB -5.0 +1 +6 70 WB -4 +2 +6 60 WB -3.5 +2.5 +5.5 20 80 WB -7 0 +6 70 WB -6 +1 +7 60 WB -5.5 +1.5 +7.5 * Cooled-**ter temperature = wet-bulb temperature of learim air plus the vetoes ehowo. . b Wet-bulb temperature of air entering sprat-filled eefoeBee text. * Length erf sir travel tbnMgb tpraffilled velvets. Evaporative Apparatus for Heat Rejection 581 side of the pond. This must be considered when selecting the location,of the pond. The drift loss can be minimized by en closing the spray pond within a louver fence 10 to 12 feet high. Fogging, which can occur during cold weather presents another hazard to buildings 0r roadways. A pond should be located with due regard for seasonal variations in wind direc tions to provide maximum cooling during the hot summer months, and minimum hazard to roadways during the winter months. Lower water temperatures can be obtained from a spray pond **>an from a cooling lake, and a much smaller area is needed. This reduces the initial cost when a natural lake is not available. This saving in cost is offset by the cost of pip ing, supports and spray nozzles. Pumping costs may also be higher due to the back pressure imposed by the spray nozzles. Atmospheric Wind Towers An atmospheric spray-filled tower (Fig. 3) is essentially a spray pond with louvered walls and an elevated spray system such as shown in Fig. 4, are 20 to 50 ft high and 8 to 16 ft wide. The hot water is distributed at the top by a spray sys tem or, more frequently, by open troughs. Except for the vagaries of the wind, the performance is quite predictable. This is done by the method described later for cross-flow mechanical-draft towera. The cooling range of spray ponds or spray towers seldom exceeds 15 F deg and it is difficult to obtain less than a 10 F deg approach unless.the cooling range is shorter than that. These performance limitations do not apply to the atmos pheric deck tower. The design can control performance by variations in tower height, water loadings, and density of the Ailing. The drift loss of a deck tower is considerable, and the nui sance is similar to that caused by the spray pond or spray towers. Both spray and deck towers are frequently located on building roofs, but the drift nuisance is seldom tolerated in congested areas. Water cooling systems that depend on the wind for air movement are not suitable for many services where the temperature requirements are more exacting. fig. 3 .... Spray filled Atmospheric Cooling Tower which usually sprays downward. While the spray pond uses large nozzles handling 25 to 50 gpm each, the spray tower will have X h. to H ia. nozzles handling 2 to 5 gpm each. Water InadingR vary from 0.6 to 3.0 gpm per sq ft of plan area, and the heights vary from 6 to 15 ft. The design conditions are generally based on a 3 mph wind, but the down-spray nozzles have an aspirating effect that'ean induce a downward air movement of up to 400 fpm. Despite this positive air move ment, wind is needed to carry the hot vapors away and pre vent recirculation. . Atmospheric spray towera seldom exceed 50 ft in length. They frequently serve small refrigerating systems or cool jacket water of internal combustion engines. 'Die performance can be estimated by calculating the outgoing wet-bulb tem perature, as with the spray pond. The cold-water temperature will be approximately equal to the outgoing wet-bulb tem perature, and performance can be estimated on that basis. An inadequate spray system will increase the water temperature several degrees. Spray towers require less basin area, less piping, and no more mftchfl.nir.aJ equipment than spray ponds. These savings may be largely offset by the extra cost of the structure. . The atmospheric deck tower contains wooden latticework decks regularly spaced from top to bottom. This filling inter rupts the falling water, greatly increases the exposed water surface, and prolongs the time of contact with the air. Towers, Mechanical-Draft Towers The mechanical-draft tower is equipped with fans to pro vide a positive and constant air flow. Since performance does not depend on the wind, it is possible to design mechanical-. draft towers for exacting conditions. The fans may operate ` to provide forced or induced draft, depending on their loca tion at the inlet or outlet of the tower. The tower may be cross-flow as shown in Fig. 5 or counter-flow as shown in Fig. 0. The addition of the fan makes it possible to design wider towers that are more compact than the long, narrow atmospheric towers. Early mechanical-draft towers were frequently of the spray-filled, forced-draft type. These sprayfilled towers are rarely used at present except in congested areas where fire codes prohibit the use of wood filling. The mechanical-draft tower is subject to recirculation of the exhaust vapors. These vapors will usually rise vertically on a still day and cause no trouble. Wind blowing across a 582 fLWI CONTROL VALVE< CHAPTER 40 CrUNDCRAIR.FLOW ..STEEP RCOUCER TAN STACK 1959 Guide .FLOW CONTROL VALVE TOWER TILLING CONCRETE INTERIOR AS REQUIRED" 'Lofurr CLIUINATOR fig. 5 .... Crossflow Mechanical Draft Tower tower creates a low-pressure area on the leeward side. The exhaust vapors may then move downward and flow back into the tower. This increases the entering wet-bulb temperature and affects the performance accordingly. Recirculation is worse with forced-draft towers because of their low exit velocities. As a result, most towers built since 1940 are of induced-draft type. The forced-draft towers, however, have the advantage of locating the mechanical equipment away from the humid exhaust-air stream. Air velocities usually vary from 300 to 400 fpm in counter flow towers. The lower friction losses in cross-flow towers make it practicable to operate them at velocities up to 600 fpm. The water loading of counter-flow towers varies from 1-2 to 8 gpm per sq ft of plan area. The upper limit is largely determined by the blanketing effect of the distribution sys tem. Since this blanketing is less pronounced in cross-flow towers, the loadings, based on plan area of the filling, can go up to 14 gpm per sq ft or higher. - Mechanical-draft towers require less plan area ponds or atmospheric towers because of the higher water lna/tinga This is quite important in roof installations where the avail able space may be limited. This feature can be of great im portance also in large industrial applications where space may be at a premium. Reduction in plan area will usually result in a saving in piping costs also. Most manufacturers guarantee a drift loss that will not exceed 0.2 percent of the circulating rate, and the Iorrar are probably less than that figure. The nuisance from drift is therefore much less with mechanical-draft towers. COOLING TOWER THEORY Basically, a water-cooling tower is a heat exchanger in which heat flows from the water to the air (1) by a flow of sensible heat from the warm water to the cooler air, and (2) by an exchange of latent heat resulting from the evaporation of a small part of the circulating water to increase the humidity ratio of the air by a corresponding amount. The general principles involved are rimiiftr to those encountered in the processes of diffusion in absorption and extraction equip ment.4* * The generally accepted concept of cooling tower perform ance is based on enthalpy potential as the driving force. This is based on the relationship in an air-water mixture proposed by Lewis4 showing that the numerical value of the coefficient of sensible heat transfer when divided by the coefficient of diffusion, approximately equals the specific heat of air at constant temperature. The relationship, involving three numerical values, each having different units, also explains why the wet-bulb temperature of a mixture of air <*-nH water fig. 6 ... Counterflow Induced Draft Cooling Tower . Evaporative Apparatus for Heat Rejection vapor approximates the'temperature of adiabatic saturation. The relationship was applied by Merkel7-8 to combine the two coefficients into one overall coefficient based on enthalpy potential. Details of the theoretical analysis have been published by various authors*-1#- u* " and those interested in the deriva tion of the equations should refer to these references. The derivations are based on the following assumptions: 1. Each particle of water is surrounded by a film of air that is at the temperature of the water and saturated with moisture- 2. The specific beat of water is unity at the temperatures encountered. 3. A constant wet-bulb temperature at varying humidity ratios represents constant enthalpy. . . 4. There is no weight loss of water due to evaporation during the cooling process- 5. The Lewis relationship applies. CONDITIONS 1 WATER L FLOW LB PER HR 583 ' (square foot overall average wetted area) (Btu en thalpy difference per pound of dry air). L *" water rate, pounds per hour. $ = temperature of water in tower, Fahrenheit. 6, -* temperature of inlet water, Fahrenheit. 8, " temperature of outlet water, Fahrenheit. V ** active tower volume, cubic feet. Z -- height of filled volume, feet. Either Equation 2 or 4 applies, but Equation 4 is more commonly used to reduce performance conditions to a nu merical value called the Number of Transfer Units (MTU)- A transfer unit is related to a set of performance conditions which are such as to h-iaVa the right-hand tide of the equation equal unity. This is a condition in which the temperature change equals the mean driving force. The (NTU) evaluates the degrcc-of-difficulty by expressing the rate of temperature change per square foot of plan area per Btu of mean driving force. _ The (NTU) applies to a vertical column of tower having one sq ft of plan area, a height Z and a volume V. Since V and Z are numerically equal ACTIVE TOWER VOLUME V \\ G LB PER HR CONDITIONS 2 Considering the cooling tower shown in Fig. 7 on the basis of these assumptions, the heat transfer per square foot of plan area in an incremental volume dV is 7)(dA) - Ka(h' - hm)dV (1) Integration gives the familiar equation . KaV f1 dh G " ] , h' - K (2) This is the Unit-Volume Coefficient, obtained by dividing (NTU) by height. It evaluates the rate of temperature change per cubic foot of tower per square foot of plan area per Btu of mean driving force. This refers to temperature change with out regard to the amount of water being cooled. Transposing L This is the overall coefficient and evaluates the Btu trans ferred per cubic foot of tower per square foot of plan area per Btu of mean driving force. Equation 4 may be evaluated by a process of mechanical or graphical integration with the aid of a temperature-en thalpy diagram such as is shown in Big. 8. The water enters the tower at temperature fli, having enthalpy hf. As it is cooled, the enthalpy of the air film surrounding it follows the saturation curve to temperature 0* where the enthalpy is It is more convenient to analyse cooling tower performance on the basis of water temperature, so and ` KaV rl da L " Jt hr -- h* (3) (4) where a = overall average wetted area (surface of water drops plus wetted tower surface), square fee\ per cubic foot of active tower volume. G = weight rate of flow of air, pounds of dry air per hour. ~ eothalpy of air-vapor mixture, Btu per pound of dry , air. A* " enthalpy of saturated air-vapor mixture at water temperature, Btu per pound of dry air. K * overall energy unit conductance, Btu per (hour) fig. 8 .... Temperature-Enthalpy Diagram for Air-Water Vapor Mixture Showing Operating Lines for Example 2 584 1 Wafer Trap. $ 84 85 86 87 88 89 90 95 100 105 110 CHAPTER 40 Table 3 .... Sequence of Mechanical Integration Tower Performance 2 Enthalpy of fSm h' 3 Enthalpy of Air ht 4 Enthalpy Diff. fc'-ffe . s 1 6 as A Ifc'-fc.) 7 2_*_ 48.22 49.43 50.66 51.93 53.23 54.56 55.93 63.32 71.73 81.34 92.34 38.61 39.81 41.01 42.21 43.41 44.61 45.81 51.81 57.81 63.81 69.81 9.61 9.62 9.65 9.72 9.82 9.95 10.12 11.51 13.92 17.53 22.53 0.1042 0.1041 0.1038 0.1030 0.1020 0.1006 0.0988 0:0868 0.0718 0.0570 0.0445 . 0.1042 0.1039 0.1034 0.1025 0.1013 0.1002 0.4640 0.3965 0.3220 0.2537 0.1042 0.2081 0.3115 0.4140 0.5153 0.6155 1.0795 1.4760 1.7980 2.0517 1959 Guide 8 Coding Bone* 1 2 3 4 5 6 11 16 21 26 hi. Air enters the tower at wet-bulb temperature 4 having an enthalpy of ht, which is plotted vertically below hj'. Since the heat removed from die water equals the heat added to die air, the enthalpy increase per pound of dry air equals the temperature change of the water multiplied by the liquid/gas (L/G) ratio. The enthalpy of the air, therefore, increases along a straight line having a slope equalling L/G and terminating at ht which is vertically below hi. The driving force at any section of the tower ia h* -- ha, the vertical distance be tween the two operating curves. Example 1; It is desired to cool 300 gpm (150,000 lb of water per hr) from 110 to 84 F with 3050 cfm (125,000 lb of dry air per nr) with an entering wet-bulb temperature of 75 F. Calculate the (NTU) showing the successive steps in tabular form. Solution: The sequence of steps ia the mechanical integra tion is shown in Table 3. Water temperature is entered in Column 1 in even, but not necessarily equal, increments. One-degree increments are used from 84 to 90 F where the potential difference is email, and the effect of-the reciprocal is large. Little accuracy is sacrificed by using 5-degree increments from 90 to 110 F where the potential difference is larger and its reciprocal smaller. Column 2 shows the enthalpy of saturated air corresponding to the tempera tures in Column 1. Air enters the tower at a wet-bulb tempera ture of 75 F, having an enthalpy of 38.61 Btu per lb of dry air. This value is entered at the top of Column 3. The enthalpy of the air increases by Ah = The L/G ratio is = 1-2 so Oh equals 1.2 Btu from 84 to 90 F and 6 Btu from 90 to 110 F. These increments are added to the initial enthalpy to obtain the successive values in Column 3. The enthalpy potential dif ference in Column 4 is the difference between Columns 2 and 3. This driving force appears in the denominator of Equation 2 so the reciprocal of Column 4 is entered in Column 5. The (NTU) within each increment equals the temperature change multiplied by the average of the entering and leaving values from Column 5. The products are entered in ColumD 6. The summation of Column 6 in Column 7 gives the (NTU) for the cooling ranges in Column 8. Hence, the mechanical integration reduces the given conditions to the numerical value of 2.0517 Transfer UnUs. Example t: The cooling tower designed to handle the condi tions in Example / has a fill height of 8 ft and a plan area of 98 sq ft. Calculate the unit-volume and overall coefficients and explain their significance. Solution: The (NTU) of 2.0517 as determined in Example l signifies the tower must cool the water 2.0517 deg per Btu of mean driving force. This cooling is accomplished in 8 ft of fill height, so the unit-volume coefficient is = 0.2565. This means that each cubic foot of tower must cool the water 0.2565 degrees per Btu of mean driving force. The water loading is --gjj-- = 1563 lb per (sq ft) (hr). The overall coefficient is 0.2565 x 1563 = 400.91. This signifies that the tower must trans fer 400.91 per cu ft (hr) (Btu of mean driving force). Column 7 of Table 3 shows how the (NTU) increases with cooling range. A plot of Columns 7 vs. 8 can be used to de termine the (NTU) for intermediate cooling ranges. This curve can also be used to determine temperature distribution be cause equal increments of transfer units correspond to equal increments of tower height. The Knaar relationship between (NTU) and height provides the Haris of the procedure used to analyse crossflow cooling towers.11 Since the wafer temperature varies both horizontally and vertically in a cross-flow tower a double integration is re quired. This is accomplished by using equal increments of transfer units, representing equal increments of distance, and calculating the corresponding temperatures. Counter-flow integration progresses from the bottom of the tower upward. The cross-flow integration starts at the top of the air inlet, and progresses downward and inward. Evaporative Apparatus for Heat Rejection 585 Required and Available Coefficients Any set of performance conditions can be accomplished by an infinite number of cooling tower designs. Calculating the ` (NTU) serves to evaluate the degree-of-difficulty of the prob lem. The urtU-volwne coefficient is more specific, but it also applies to an infinite number of towers of a given height. The overall coefficient has the most significance when comparing towers of different designs that are being considered for a given duty. It evaluates the effect of variations in air rate, height, and plan area on the required coefficient. A higher required coefficient indicates that more effective filling is needed. The effectiveness of a fining is determined almost entirely by the density of the splash surface and wetted surface per cubic foot of filled volume. These calculations evaluate the problem, not tire tower. The available coefficient of a specific cooling tower is deter mined from its operating characteristics. The tower must be tested at various conditions and the data from each test re duced to a corresponding coefficient. A cooling tower coeffi cient is not constant, but varies with operating conditions. Its characteristic is established by correlating variations of the coefficient with corresponding operating conditions. The characteristic of a cooling tower closely approximates the relationship expressed by the general equation: Ka = cL*G* (7) The cooling tower manufacturer uses this procedure to de termine the characteristic of each cooling tower design. An examination of the steps taken in the solution of Ex ample 1 will show that various air rates could have been speci fied. Increasing the air rate would have reduced the degreeof-difficulty and resulted in a smaller (NTU) for a given set of conditions. Decreasing the air rate would have the opposite effect. Therefore, the required coefficient for a given set of conditions varies with the air rate. A tower will operate at a given set of conditions when the required coefficient equals the available coefficient as determined from Equation 7. DESIGN CONDITIONS The design conditions used in selecting a cooling tower are (1) the circulating water rate, (2) cooling range, (3) entering wet-bulb temperature, and (4) the approach of the coldwater to the wet-bulb temperature. These conditions are se- rmccss iected by considering the function of the cochng tower in the overall system. The system includes a process having a heat load that is .to be transmitted to the circulating water through a heat exchanger. The cooling tower rejects the heat load to the atmosphere. Certain design conditions of the system affect the design of the cooling tower. They include (1) the heat load, (2) the temperature at which it is to be removed, and (3) the wet-bulb temperature of the atmosphere to which the heat is finally rejected. The cooling tower and beat exchanger are then selected to serve these conditions. The relationship of the cooling tower to the system is shown schematically in Fig. 9, with the process represented by two heat sources op erating in series. Heat Load No definite sequence can be followed in selecting the design conditions because each item affects the choice of the others. The heat load comes closest to being a fixed quantity so can be considered first. The amount of heat rejected by typical processes is shown in Table 4. The heat is rejected at a constant temperature when vapors are condensed, as illustrated by Qt in Fig. 9. A second type of heat load, represented by Qi, consists of reducing the temperature of a fluid. Each type of heat load Has specific requirements that affect overall design. The tem perature at which the heat is removed from a process may be as important in the overall design as the heat load itself. As this temperature level decreases, the degree-of-difficulty increases at an accelerated rate, calling for larger and more expensive equipment. Higher temperatures usually result in higher operating costs, and loss of capacity in the process. Table 4 .... Heat Rejection of Typical Processes Equipment - tlu per per Sto per kw hr bhp-hr Refrigeration Compressors (reciprocating)................................. Refrigeration Compressors (ceotrifugal)....................................... Refrigeration Absorption System.. Steam Jet Refrigerating System---Steam Electric Power Plant: 500 kw......................................... 250 300 550 550 11,210 5000 kw......................................... 7500 kw......................................... 10,000 kw........................ ................. Diesel Engine Jacket & Lube Oil: Four-cycle, Supercharged.......... Four-cycle, Non-supereharged... Two-cycle, Crank-case CompresBOT.... .................................... Two-cycle, Pump Scavenging (large unit).......... ................ Two-cycle, Pump Scavenging (high speed)................................ Natural Gas Engine: Four-cycle................................ Two-cycle................ ................... 8,150 7,700 7,020 2600 3000 2000 2500 2200 45004000 586 CHAPTER 40 1959 Guide Table 5 .... Condenser Design Data Uenng Hot Water Temperotore, Got F OesiW Pretsn tn CoodffMcr Temperatore in CondtAW Beat Coodeiuer Co. F Deogn Design Steam.................... 28 in. vac 101.2 97 93 Steam.................... 27 in. vac 115.1 HO 105 Steam.................... 28 in. vac. 125.4 120 114 Ammonia.................. 185 psia* 96.0 92 88 Carbon dioxide... 1030 psig* 86.0 83 80 Methyl chloride.. 102 psig* 100.0 96 92 Dichlorodi- I fluoromethane ] 117 psig* 128 psig* 136 psig* 100.0 96 93 105.0 100 97 110.0 104 101 * Head pressure. '' Condensing Systems Each vapor has a pressure at which condensation occurs for any given temperature. This pressure increases with tem perature up to the critical temperature of the vapor, above which no amount of increased pressure causes condensation. Condensation in a process occurs at constant temperature because a constant pressure will exist in the heat exchanger. The condensing pressure is usually the controlling factor in the process, although this is obtained by designing for the corresponding temperature. Table 5 lists typical condensing data for commonly used vapors. A transfer of heat from the vapor to the circulating water requires a temperature differential between the two media. Since the vapor must condense at a constant temperature, the condensing temperature h in fig. 9 must be higher than the hot water temperature B\. It is for thin reason that the condensing temperature is largely determined by the tem perature of the warm water leaving the beat exchanger, and tire entering cold-water temperature has only a small effect. The terminal temperature difference is controlled by the amount of heat transfer surface in the condenser. Economi cally sized condensers are usually designed to operate with 3 to 10 F deg temperature difference between the vapor and hot water. Fluid Cooling Different conditions exist when cooling a fluid such as milk, natural gas, or distillate. When this is done in a counter-flow heat exchanger, two terminal differences are involved. The fluid can be cooled to a temperature approaching that of the entering cold water, and the circulating water can be heated to a temperature approaching the hottest temperature of the Quid. A terminal temperature difference must exist at both the hot and cold end of the exchanger, but the temperature of the fluid leaving the exchanger can be colder than the hot water temperature. Water Gradating Rate . The heat load on the system is determined by the process being served, and when this value is fixed, the circulating water rate determines the temperature rise in the heat ex changer. The cooling range in the cooling tower is obviously equal to the rise in the exchanger when the two are operating in equilibrium. The type of heat load and the characteristics of a cooling tower govern the selection of the optimum circu lating rate. Increasing the circulating rate while holding the other operating conditions of a cooling tower constant, will reduce the cooling range. The cold-water temperature will increase, but the hot-water temperature will decrease to a greater extent. A high circulating rate and a short cooling range is advantageous when condensing vapors because the lower hot-water temperature has more effect on condensing temperature than the smaller increase in cold-water tempera ture. This advantage can be offset by greater power require ments for pumping, and possibly by the increased cost for larger piping. Cooling a fluid presents a different problem. The cooling tower must deliver the cold water at a temperature that is below that of the cooled fluid, and this is more easily ac complished with a low water rate. The process may involve several heat loads, one of which requires a low temperature and the other can be removed at a much higher level. The size of a cooling tower is governed more by the cold-water tem perature than by the cooling range. Once the cold-water temperature is fixed, it is desirable to increase the range as much as possible. A single cooling tower serving several heat loads in series is usually more economical than a number of individual towers. A refrigerating system rejecting 250 Btu per ton imposes a load on the cooling tower of 30 (F deg) (gallons) per ton. The standard practice is to design the towers for 3, 4 or 5 gpm per ton, corresponding to cooling ranges of 10, 7M and 6 F deg, respectively. Towera serving steam condensers usually operate with a range of 12 to 19 F deg. Oil refineries usually design for a cooling range of 25 F deg or more. Heat Exchanger The cooling tower operates in conjunction with the heat exchanger in transferring heat from the process to the atmos phere. Increasing the size of either one will reduce the re quired size of the other. The optimum conditions are deter mined by considering the initial and operating costs of several combinations of cooling towera and beat exchangers: Process Characteristics The type of process must be considered when selecting tire design conditions of the system. This is particularly true of the temperature at which heat is removed from the process. Am monia refrigerating systems are frequently designed to operate at 185 psig head pressure, corresponding to 96 F condensing temperature. This will require cooling water leaving the con denser at about 90 F. It will be impractical in most localities to select a cooling tower that will not exceed that temperature during brief periods. An increase in the temperature of the circulating water will raise tile bead pressure and increase the power requirement of the compressor. The increased head pressure also reduces the refrigerating capacity, but the sys tem can be designed to perform acceptably at such times. A carbon dioxide refrigerating system represents a more serious situation. The critical temperature of the-refrigerant is 88.4 F so the system will not function if that temperature is exceeded. The design conditions are also influenced by the process served by a refrigerating system. The maximum refrigerating load does not necessarily coincide with peak wet-bulb temperatures so a reduction in capacity may not be serious. That may not Evaporative Apparatus for Heat Rejection 587 be true in the case of air conditioning if the maximum capacity is needed when wet-bulb temperature may be at its highest. The efficiency, capacity and operating costs of a steam electric generating station all improve as the condensing tem perature decreases. Designing for maximum performance at the most adverse conditions will result in a plant having ex cess capacity most of the time. The most adverse conditions occur during summer daylight hours, and peak power loads formerly came during winter evening hours. This gave the happy combination of peak demand during favorable operat ing conditions, and a low demand when the conditions were adverse. The power industry is profiting from the expansion of air conditioning, with the result that the peak load is be ginning to coincide with the most adverse operating condi tions. A generating plant can be designed to accept higher operating costs during such periods, but higher operating temperatures can reduce capacity below the required de mand. The capacity of an industrial operation such as an oil refinery will vary with the temperature of the cooling tower. Such a process may be so involved that it is not practicable to vary the output with fluctuation of the weather. These plants usually are compelled to operate at a constant rate that can be maintained from day to day. All processes ging cooling water are faced with variations in water temperature. Higher temperatures increase operating costs and reduce capacity. These can be overcome by installing a larger plant or a larger cooling system, with the result that one portion of the equipment will have excess capacity during most of the year. The overall design must be based on (1) the minimum permissible capacity under the most adverse conditions and (2) an economic study showing the effect of changes in the size of the components on initial cost and operating expense. Wet-Bulb Temperature The wet-bulb temperature is beyond the control of the designer. It fluctuates during the day, and throughout' the year. The annual averages should be studied and correlated with the characteristics of the process. Peak wet-bulb tem peratures are usually of short duration so have little effect on annual operating costs, but the effect of these conditions in limiting capacity must be considered. The design wetbulb temperature should be selected on the basis of the num ber of hours of the four summer months of June through September (or of the year) that-it can be exceeded during an average year. A common practice in air conditioning is to select a wet-bulb temperature that will not be exceeded more than 5 percent of the time during the four summer months. Various groups are cooperating in compiling weather data for this type of study. A limited portion of the data are tabu lated in Table 2, Chapter 13. More complete summer weather data, statistics, charts, maps, and technical analysis have been prepared by Albright.1* When the circulating rate and water temperatures have been selected, the size of the cooling tower will be increased by. selecting a higher wet-bulb temperature. Selecting the design wet-bulb temperature makes it possible to consider various combinations of cooling towers and heat exchangers. The overall design will, of necessity, consider the worst possible conditions. This will correspond to the maximum wet-bulb temperature for the locality, and the highest permissible proc ess temperature. All components should be selected with these conditions in mind, but testing will be easier if the same * equipment is designed and guaranteed around a lower wetbulb temperature. Table 6 shows that an arnmnnia refrigerat Toble 6 .... Alternate Design Conditions for Ammonia Refrigerating System, Showing Annual Hours the Design Wet-bulb Temperature b Attained Wet-Bvtb Temp. Hot Woter Temp. FF Heod Fret*. P" Hoar* Attoinofeto 78 92.0 185 75 88.5 174 70 86.0 166 12 161 750 ing system might be designed for a 78 F wet-bulb temperature. That temperature will prevail 12 hours a summer, and for brief periods of time. Designing the gamp, equipment around a lower wet-bulb temperature greatly increases the amount of time that teste can be conducted at or near the design condi tions. SaECTlON AND EVALUATION The characteristics of the various types of water cooling equipment will influence the final selection. The require ments of the process, and physical conditions of the plant will impose further restrictions. These factors will determine the design conditions to be used and indicate the general type of equipment that will be most desirable. A wide variety of cool ing towers will, nevertheless, be capable of meeting the design conditions. Competitive designs may be similar, but they will not be identical. The same design can be considered in various frame sizes, representing different plan areas or heights. An increase of frame size will enable a tower to meet the condi tions with less total air flow, and will reduce horsepower re quirements. As a general rule, an increase of frame size in creases the initial cost but reduces operating costs. Optimum size is determined from an economic evaluation that will in clude such items as the following: CAPITAL INVESTMENT 1. Total erected cost of cooling tower. 2. Basin, grillage, and value of the space occupied. 3. Cost of pump and prime mover. 4. Electric wiring to pump and fan motors. 5. Electrical controls and switch gear. 6. Cost of piping from tower inlet to point on tower nearest to plant. 7. Sump, screens, overflow, and make-up lines not furnished by manufacturer. 8. Shut-off and control valves not furnished by manufac turer. 9. Walkways, ladders, etc., providing access to tower. . OPERATING COSTS . 1. Demand charge, if it enters into cost. 2. Energy costs for fans and pumps, based on 3000 to 7000 hr per yr. 3. Amortization of investment, over a period varying from 3 to 30 years. 4. Maintenance and repairs. / Other factors to consider are safety features, conformity to building codes, general design and rigidity of structures, avail ability of spare parts, experience and reliability of manufac turer, and operating flexibility for economical operation at varying loads or seasonal changes. Failure to perform in accordance with the guarantee usually proves costly to the 588 CHAPTER 40 1959 Guide purchaser regardless of subsequent adjustments made by the manufacturer. The capability of a cooling tower should be evaluated prior to purchase, and acceptance tests con ducted during the warranty period. nated by a reduction in the tip speed of the fan. This is sel dom successful because the sound is a function of horsepower as well as tip speed. Both of these must be reduced to lower the sound level. TOWER LOCATION Small cooling towers are frequently located on the roof or offset of a building, but large towers must be located on the ground. Proper location and orientation are needed in either case to insure satisfactory performance. A most important factor is to provide for a free flow of air to and from the tower. The air flow to a tower can be obstructed by adjacent struc tures or by screening walls in the case of roof installations. Such walls must be provided with openings that are at least equal to the inlet area of the tower. If the opening in the wall is not immediately adjacent to the tower inlet, the wall must be set back far enough to allow the air to flow around or under the tower to the inlet. Downdrafts are created by wind blowing over a cooling tower or adjacent structures. The exhaust air is carried down ward and can re-enter the tower from the leeward side. Since such recirculation raises the entering wet-bulb temperature a location should be selected that results in the least loss of performance during the hottest weather. Recirculation is usually the least with an end wind unless the tower is over 300 ft long. Adjacent structures and topography affect the wind. They should be considered carefully together with U. S. Weather Bureau data for the locality. A cooling tower should not be located where the prevailing summer wind will carry heat to it from an external source or from another cool ing tower. A properly designed cooling tower will have a drift loss not more than 0.2 percent of the circulating rate. A small amount of water in the exhaust air is unavoidable, but it can be ob jectionable if the droplets fall on parked automobiles, nearby windows or power lines.. Evaporation leaves a deposit of the dissolved solids. The moisture content of the air passing through a cooling tower is increased due to the evaporative cooling of the water. Condensation is unavoidable if the vapors strike a cool sur face and cause a hazard that can be serious during freezing weather. During periods of high relative humidity, fogging occurs as the exhaust air mirra with the atmosphere and is cooled below its dew point. Fogging is usually worse in the ` spring or fall when the ambient air is humid and cool but not too cold. Wans air during the summer is capable of absorbing the excess moisture without producing a fog. Less water evaporates in the tower during extremely cold weather be cause the humidity ratio is reduced, so the fog is dissipated rather rapidly. . The drift nuisance is usually confined to an area immedi ately adjacent to the tower although high winds can carry it several hundred feet at times. Fogging, however, is less lo calized and can occur close to the tower or settle to the ground a considerable distance away. Noise problems occur when cooling towers are located in congested areas. This applies particularly to mndl towers rather than large industrial installations. The sound is cre ated by the falling water or fans and air movement. The water noise does not carry far but is quite noticeable adjacent to a tower. The sound of the fans may be audible at a considerable distance away from the tower if it is not deflected by inter vening structures. Deflecting screens are of some value, and acoustical treatment is quite effective but expensive. It is commonly believed that objectionable noise can be elimi OPERATION AND MAINTENANCE Most cooling tower manufacturers issue operating and maintenance instructions. These bulletins should be placed in the hands of operating personnel for their guidance. Water Treatment The general discussion of this subject in Chapter 55 offers detailed information on scale deposition, corrosion, and con trol of biological fouling. The dissolved solids in a circulating system are concentrated as water is lost by evaporation. The evaporation averages 0.8 percent' of the circulating rate for each 10 F deg of cooling range. Excessive concentration is prevented by wasting a portion of the circulating water as blowdown. The make-up water, replacing losses due to evap oration, drift and blowdown, introduces dissolved solids into the system. An equal amount of solids must be removed by the drift and blowdown. Expressing all terms as a percentage of the circulating rate, the number of concentrations in the system is: No. of Cone. Evaporation + drift + blowdown (8) Drift + blowdown The form of Equation 8 shows that a amount of blow down is highly effective, but higher rates arc of little advan tage. Drift loss alone will maintain about 15 concentrations. This is rapidly reduced to 3 or 4 concentrations with 1 per cent blowdown, but an increase to 100 per cent blowdown brings the system down to one concentration. Draining the system periodically is a poor substitute for continuous blow down, because the concentration builds up to the maximum within a few hours. . Towers operating continuously are usually arranged for blowdown by maintaining a water level in the collecting basin that allows the desired quantity to be wasted at the overflow connection. Placing the blowdown connection in the hot-water lin? adjacent to the tower inlet prevents unnecessary waste when the pump is stopped. This is recommended'for inter mittent operation. Many small .installations rely on blowdown for water con ditioning, and use so supplementary water treatment. Larger installations find it desirable to use chemical treatment in the system, and most of these processes require a controlled blow down rate. Chapter 55 discusses the chemicals used to control scale, corrosion and biological fouling. Wood Deterioration - Wood is one of the most durable materials, but it can be destroyed by chemical action or by organisms producing de cay. Until 1950, the deterioration of cooling tower lumber was looked upon as the result of chemical action, but later investi gations indicate it is largely due to micro-biological attack.14 Deterioration can be expected if sodium carbonate is present in the water. This was formerly classed as a chemical attack although sodium carbonate is a rather poor pulping agent. The deteriorated wood almost invariably contains wooddestroying organisms, so the actual cause of the deterioration can be chemical, micro-biological or a combination of the two. Chlorine is frequently used to control the growth of slime Evaporative Apparatus for Heat Rejection 589 and that foul the circulating system. This is a powerful agent that attacks the wood if used excessively. The action bleaches the surface of the wood and loosens the fibers, allowing them to wash away and collect in the heat exchangers or on the screens. A more common type of surface attack, however, is caused by soft rot organisms. The more durable species of wood contain fungicidal materials that are removed by oxidizing agents such as chlorine. These materials are also removed by normal leaching. Decay organisms are widespread in nature, serving a use ful necessary purpose in sewage disposal systems or in the disintegration of dead trees in the forest. The same proc ess is highly undesirable when it occurs in structural lumber. It is prevented by impregnating the lumber with preservatives that are toxic to the organisms. The use of treated lumber in cooling towers has been increasing since 1953. Service records accumulated since that time indicate that the service life of cooling tower lumber can be economically extended by pre servative treatment. The use of treated wood increases the initial cost of a cooling tower about 10 percent. Preservatives can be applied by the double diffusion method to existing cooling towers built of untreated lumber.14 into the sump where its level is maintained by means of a float valve. The eliminator plates are placed in the path of the water-air mixture so as to remove the entrained water. Since the air leaving the unit is almost completely saturated, care must be taken in locating discharge ducts to prevent condensation. Evaporative condensers are available in sizes up to 300 tons or more. These units use only a small portion of the water required for a waste-water cooled condenser. The water is vaporized by the heat of the refrigerant. Each pound of water used extracts approximately 1000 Btu from toe refrigerant, whereas under commonly used rating conditions where the water temperature rise is 20 F deg, each pound of water Winter Operation The basin and piping must be drained, or otherwise pro tected, if a cooling tower is shut down during freezing weather. Towers that are Bhut down frequently are preferably operated with a dry begin. The tower is installed at an elevation that allows the basin to drain into an indoor tank to which the cir culating pump is connected. Water-cooling towers operating in freezing weather are subject to ice formation, particularly at the airinlet. This is not influenced by the temperature of the circulating water since tire icing occurs where fine drops splash out and strike relatively dry surfaces in the entering air stream. Stopping the fans temporarily allows the water to fall vertically across'' the inlet, and much of the ice is melted. Ice that is not melted in this manner can be removed by reversing the fans for 15 or 20 minutes. Air flow is obstructed by the ice, causing water temperatures to increase drastically. Since the water tempera ture increases when icing occurs, it is not posable to use ther mostatic controls to stop or reverse the fans. CONTROL OF COOLING TOWERS Other than the usual electrical interlocks with the refrigera tion system, few automatic controls are used on cooling towers. Sometimes the ten is turned off automatically to re duce capacity in cool weather. Towers not of the dry-basin type may have drain valves controlled by outdoor thermo stats to prevent freeze-up of the water in the pan. EVAPORATIVE CONDENSERS The evaporative condenser combines the functions of the condenser and cooling tower by using a minimum amount of water on a surface, cooling it to approximately the wet-bulb temperature of the surrounding atmosphere. The end view of a typical evaporative condenser is shown in Fig. 10. The fan draws the air over a condenser surface which is kept wet by a water spray. The discharge refrigerant gas from the compressor enters the top of the condenser coiL The liquid refrigerant is drained from the bottom of the coil into a liquid receiver, and then circulates through the remain ing portion of the system in the usual way. The water is circulated through the spray nozzles and drops extracts only 20 Btu from the refrigerant. The water used including the loss by entrainment in the discharge air, the blow down, anH the evaporation, amounts to about 3 to 5 percent of that which would be required for a water-cooled condenser. ' The evaporative condenser requires more maintenance, occupies greater space (must be located where air is available), and hag a higher first cost than the water-cooled condenser, but where the use of water is restricted or expensive, the evaporative condenser hag become widely accepted. Compared with a water-cooled condenser and cooling tower, which have about the g*mf> heat dissipating capacity, the evaporative ranrfansgr hag the advantage of lower cost and smaller space requirements. Control of Evaporative Condensers An electrical interlock is usually provided to prevent the refrigeration system from operating until the pump and fan 590 CHAPTER 40 1959 Guide of the evaporative condenser have been started. In some cases, an automatic damper is used on the inlet of the evaporative to provide proportional control of head pressure on the refrigeration system. See Chapter 43 for general information on controls. - REFERENCES ' W. D. Collins: Temperature of Water Available for Industrial Use in the United States (U. S. Geological Survey, Water Supply Paper No. 520F). *R. F. Throne: Cooling performance of an industrialised lake surface (Power, September 1951). S. Hori. U. A. Patehett, and L. M. K. Boelter: Design of spray cooling ponds (ASHVB Journal Section, Heating, Piping and Air Conditioning, October 1942, p. 624). W. H. Walker, W. K. Lewis, W. H. McAdams, and E. R. Gilliland: Principles of Chemical Engineering (McGraw-Hill Co., New York, 1937, p. 4S0). . D. Q. Kern: Process Heat Transfer (McGraw-Hill Co., New York, 1950, p. 563). * W. K- Lewis: The evaporation of a liquid into a gas (ASMS Transactions, Vol. 44, 1922, p. 325). F. Merkel: Verdustungs kuhlung (Forschungarbeiien, No. 275, 1925). * H. B. Nottage: Merkel's cooling diagram as a performance correlation for air-water evaporative cooling system (ASHVE Transactions, Vol. 47, 1941, p. 429). * W. H. McAdams: Heat Transmission (McGraw-Hill Co., New York, 1933, p. 157). . 10 A. L. London, H. B. Nottage, and L. M. K. Boelter: De termination of unit conductance for heat and mass transfer by the transient method (Industrial and Engineering Chemistry, April 1941, p. 467). 11 Joseph Lichtenstein: Performance and selection of me chanical-draft cooling towers (ASMS Transactions, 1943, p. 779). - u D. R. Baker and L. T. Mart: Analysing cooling tower performance by the unit-volume coefficient (Chemical En gineering, December 1952, p. 196). u J. C Albright and D. R. Baker: Summer Weather Data (TheMarfey Co., 1944). . 14 D. R. Baker: Studies relative to protection of cooling tower lumber (ASME Oil, Gas and Power Division Proceedings, June 1954). CHAPTER 41 EVAPORATIVE AIR COOLING AND HUMIDIFICATION Apparatus hr Humidification, Spray Generation, Spray Distribution, Unit Humidifiers, Air Washers, Humidification with ' Air V/ashers, Oe/wradificof/on and Cooling with Air Washers, Evaporative Air Cooling, Types of Direct Evaporative-Cooling Equipment, Design Considerations, Controls, Maintenance EVAPORATIVE air cooling and humidification increase induce air flow through a easing or duct for distribution of the moisture content of an air stream or the air in a the spray. Fan propulsion uses a power-driven fan to dis selected space, with or without a change in dry-bulb tempera tribute the spray. ture. , Evaporative air cooling applies the well-known phenome Atomizing Humidifiers non of evaporating water at ambient temperature into an air stream. If no heat is added during the process, the dry-bulb temperature of the air stream is reduced along the thermo dynamic wet-bulb temperature line with a consequent in crease in latent heat and moisture content. Humidification, used industrially and in residential air conditioning and heating systems, may be accomplished by evaporative air-cooling apparatus, by the direct introduction of water spray into the air stream ot space either by heated evaporating pans or steam jets. Some equipment can be used In several types of atomizing humidifiers nozzles are placed within the room. Compressed air effects complete atomiza tion of the water which is converted into vapor by the heat of the room air. In some of these nozzles an aspirating effect draws the water into the nozzle and atomizes it. Others are operated on a combined air and water pressure. It is usual for nozzles of the water-pressure type to be controlled by a diaphragm valve actuated by the pressure of the atomizing air. for both cooling and hnmiHifirAtimi High-Duty Humidifiers APPARATUS FOR HUMIDIFICATION Humidification may be direct or indirect, ije., water in droplets or vapor form may be' introduced directly into the humidified space, or previously humidified air may be circu lated in or through the space. Evaporative air cooling is al ways indirect although the cooling may be accomplished by wetted surface or secondary cool surface. The classification of apparatus used for humidification and evaporative air cooling is showmin Table 1. Water is supplied at about 150 prig to an impact-type spray-generating nozzle located in a cylindrical caring. A drainage pan provides for the collection of unevaporated wa ter which is returned to a filter tank. A' powerful air current from a fan mounted above the unit, flows through tire cyl inder and is charged with moisture. Air discharges from an opening below at a high velocity in a complete and nearly horizontal circle. The spray is evaporated and the resulting vapor is diffused and distributed. HUMIDIFICATION SPRAY GENERATION AND DISTRIBUTION Spray generation is obtained by (1) compressed air, (2) impact, (3) hydraulic separation, and (4) mpp-honical sepa ration. Atomisation can be accomplished by the use of a com pressed air jet to reduce the water particles to a fine spray. With the impact method, a jet of water under pressure im pinges directly on the end of a small round wire. Where hy draulic separation is employed, a jet of water enters a cy lindrical chamber and escapes through an axial port with a rapid rotation which causes it to separate in a fine cone shaped spray. In the mechanical separation process, water is thrown by centrifugal force from the surface of a rapidly revolving disc and separates into particles sufficiently small to be utilized in certain types of mechanical humidifiers. Spray distribution is obtained by (1) air jet, (2) induction, and (3) fan propulsion. Air-jet distribution utilizes the atomizing jet to distribute the spray through the space. Induction distribution utilizes the aspirating effect of an impact or centrifugal spray jet to Spray Humidifiers . This type uses a spray nozzle in a cylindrical casing equipped with a drainage pan. The aspirating effect of the nozzle induces a moderate air current through the casing which distributes the entrained spray. The general method of circulating and returning the . water is rimflar to that em ployed for high-duty humidifiers. A suitable pump and cen trally-located filter tank are required. . Self-Contained Humidifiers In this type mechanical or centrifugal means are used to generate and distribute spray. They may be used either singly or in groups. In large installations, where suitable connections are provided to permit the cleaning and servicing of individual units without affecting the'room as. a whole, group control of the water and power may be employed. UNIT HUMIDIFIERS The term unit humidifier denotes an assembly of elements the principal function of which is to humidify. Hie essential 592 CHAPTER 41 1959 Guide element of a unit humidifier is an atomizer or evaporator. To this may be added a fan, a heater, outlet vanes or diffusers, and a housing to enclose the various parts. Unit humidifiers fall into four general classifications, de pending on the method of causing evaporation. These are as follows: (1) Nozzle Type, (2) Rotary Type, (3) Cascade Type, and (4) Heater Type. , In the nozzle type of humidifier water is sprayed into the air and evaporation is effected by adiabatic exchange of en ergy. Unite of this type in simplest form, spray a fine mist of water directly into the air in a space. They are used to a great extent in the textile industry. The rotary type of humidifier generates and distributes by m^hanirAl separation using rotating discs. In all other respects, this type of humidifier is similar to the nozzle type. It has the advantage over the nozzle type of being less likely to become clogged. . In the cascade type the humidification takes place by wa ter falling in sheets over a series of baffles or trays. This type is usually furnished with a fan, air heater, and air filter, all enclosed in a housing. In the heater type of humidifier the water is heated either to the boiling point or to a temperature at which the water vapor readily passes into the air stream. In the simplest form the heating element using steam, hot water, gas, oil, or elec tricity is placed in a pan or vessel of water, and the vapor passes from the surface of the water to the stream of air. A modification of this type of humidifier is the combination of spray nozzle and heater type in which the water is sprayed over a hot surface and evaporated. It has the disadvantage of accumulating scale on the surfaces of the vessel or heating sur face. Unit humidifiers are usually controlled by a two-position room humidistat operating a controlled devioe which func tions to start and stop the humidifying action. This may be a valve on the water supply to the humidifier. The fan, if used, normally is also turned off by the humidistat. The con trolled device operates the source of heat in the heater type of humidifier. See Chapter 43 for a general discussion of hu midity controls. AIR WASHERS Spray-Type Washers A spray-type air washer consists essentially of a chamber or casing containing a spray nozzle system, a tank for col lecting the spray water as it falls, and an eliminator section at the discharge end for removal of entrained drops of water from the air. A pump recirculates water at a rate greatly in of the evaporation rate. Intimate contact between the spray water and the flowing air causes heat transfer between the air and the water, resulting in either humidification or rffrhumifflfirAtinn, depending upon the method of operation and the relative temperatures of air and spray water. To prevent h^lrlash of spray ahead of the washer chamber, and to provide more uniform air distribution, perforated in let plates, horizontal louvers or vertical eliminator baffles may be provided in the washer inlet. Inlet diffusion plates may be required when the air and water spray are in the sarnu direction because eddy currents may be present. Elimi nator baffles are used where one or more of the water sprays opposes the air flow and is sufficiently close to the entering end that water might come out. At the outlet end of the washer, suitable eliminator plates are placed and may or may not be provided with flooding devices. These plates or blades, for the removal of entrained moisture, may cause four to six directional air changes and present as many as four effective hooked edges for trapping the water. Blades usu ally have bends at 30 deg to the direction .of air flow. Sharper bends add substantially to the resistance without improving the elimination materially. Vertical type baffles may be pro vided with flooding devices where the air contains large quan tities of particulate matter or lint, as in cotton mills, to pre vent build-up on the baffle blades. ' Table 1 .... Classification of Apparatus Used for Humidification and Evaporative Air Cooling Hootrditfcairon * fvoporofivo Air Cooling Designation tndlrecf Direct Primary ` Wat Surface* . Dry Surface or Secondary Cool Surface two Stage Residential Commercial or Indus trial 1. Evaporating pans with "wick action" water transport. 2. Externally heated evaporator pans (electric or steam heat). 3. Porous, extended surface pad types. 1. Atomisers or sprays. 1. Drip type, usually nonmet&l pads. 2. Stinger type, usu ally metal pads. 3. Rotary type, usu ally metal screens. 1. Blast coils cooled by cool ing tower water. 1. Air washers, spray and fill types. 1. Pneumatic atomisation. 2. Pressure atom ization. 3. Centrifugal atomization. 4. Steam jets. 1. Drip type, usually non-metai pads. 2. Stinger type, usually metal pads. 3. Spray or washer type. 4. Rotary type, usu ally metal screens. 1. Blast coils cooled by cool ing tower water. 1. Secondary cool surface cooling followed by pri mary wet sur face or spray cooling. Evaporative Air Cooling and Humidification PLAN 593 installation. In general, the width and height of an air washer will depend on the space available. Washers of nearly equal height and width are desirable from an air flow and standpoint, although these proportions are not necessary. The length of washers varies considerably. A space of ap proximately 2Yz to 414 ft between spray Hanka jg and the first and last banks of sprays are located about 1 to 114 ft from the entering or leaving end of the washer. In addition, air washers may be furnished with heating or cool ing coils within the washer chamber. These coils may affect the overall length of the washer. Spray water requirements for spray-type air washers used for washing or evaporative cooling vary from 4 gpm with a single hank to 10 gpm for double banks per 1000 cfm. Pump ing heads will usually be in the range from 55 to 80 ft of water fig. 1------- Typical Single-Bank Air Washer Pigs. 1 and 2 show the essential construction features of conventional spray-type air washers. Intimate contact be tween the air and water is secured (1) by breaking the water into fine drops, (2) by passing the air over the surfaces con tinuously wetted by water, or (3) by a combination of the two. Essential requirements in the air washer operation are: uniform distribution of the air across the spray chamber, air velocities of from 400 to 700 fpm in the washer chamber, an adequate amount of spray water broken-up into fine drop lets at pressures of from 15 to 30 peig, good spray distribu tion across the air stream, sufficient length of travel through the spray and wetted surfaces, and the elimination of free moisture from the outlet air. - Expected performance, physical size, length, number of sprays, etc., vary greatly depending on the functions of the fig. 2 .... Typical Two-Bank Air Washer fig. 3 .... Typical Fill-Type Air Washer depending on spray pressure, height of apparatus, pressure losses in pipe and strainers, etc. The resistance to air flow through an air washer varies with the type and number of baffles, eliminators, and wetted surfaces; number of spray hanks and their direction; air velocity; size and type of other resistances such as cooling - and heating coils; and other factors such as air density. Re sistance may be as low as Vk in. or high as 1 in. water column. It is therefore necessary that the manufacturer be consulted with regard to the resistance of any particular washer de sign combination. Fill-Type Washers Other air washer types achieve contact between air and water by passing the air through cells packed with glass fibers or sheets of specially designed media. See Fig. 3. These wash ers have the cells arranged in tiers over which water is dis tributed at low pressure. The cells are followed by conven- 594 CHAPTER 41 1959 Guide tional blade type or glass mat eliminators. With water drainage provided for each cell tier, most of the stratification found in spray-type washers is avoided. An essential requirement of operation of this type of air washer is good distribution of water over the face of the cells. When compared with conventional spray-type washers, the water 'requirements are much lower, approximately 4 gpm per 1000 cfm for ordinary washing and evaporative cooling, and the pumping head is approximately one-half the head of conventional spray-type washers. - " Humidification with Air Washers Air humidification can be accomplished in three ways with an air washer. These are: (1) use of recirculated spray water without prior treatment of the air; (2) preheating the air and washing it with recirculated spray water; and (3) using heated spray water. In any air washing installation the air should not enter the washer with a wet-bulb temperature less than 35 F. This is a precaution to eliminate the danger of freezing the spray water. . Method 1. Except for the small amount of energy added from outside by the recirculating pump in the form of shaft work, and for the small amount of heat leakage from out side into the apparatus, including the pump and its con necting piping, the process would be strictly adiabatic. Evap oration from the liquid spray would therefore be expected to bring the air immediately in contact with it to saturation adiabatically; and, since the liquid is recirculated, its tem perature would be expected to adjust to the thermodynamic wet-bulb temperature of the entering air. ' It does not follow from the foregoing reasoning that the whole air stream is brought to complete saturation, but merely that its state point should move along a line of con stant thermodynamic wet-bulb temperature as explained in Chapter 3. The extent to which the leaving air temperature approaches the thermodynamic wet-bulb temperature of the entering air, or the extent to which complete saturation is approached, is conveniently expressed by a ratio known as humidifying effectiveness or saturating effectiveness, and is defined in Equation 1 as a- X 100 (1) where eh " humidifying or saturating effectiveness, percent, ft " dry-bulb temperature of the entering air, Fahrenheit, (j ~ dry-bulb temperature of the leaving air, Fahrenheit. t' " thermodynamic wet-bulb temperature of the entering air, Fahrenheit. The following may be taken as representative of the hu midifying or saturating effectiveness of a spray-type air washer for the arrangements stated: Arrangement 1libnU U Ft NESS--% 1 bank downstream 1 bank downstream 1 bank upstream 2 banks downstream - 2 banks opposing each other 2 banks upstream 4 6 6 8 to 10 8 to 10 8 to 10 50-00 60-75 65-80 80-00 85-95 90-08 The humidifying or saturating effectiveness of a washer is dependent upon the-essential items of design mentioned in the section Air Washers. Other conditions being the same, a low velocity of air Sow is conducive to high humidifying ef fectiveness. Method . The preheating of the air increases both the dry- and wet-bulb temperatures, and lowers the relative hu midity, but does not alter the humidity ratio (pounds of wa ter vapor per pound dry air). At a higher wet-bulb tempera ture, but the same humidity ratio, more water can be absorbed per pound of dry air in pasting through the washer, assum ing that the humidifying effectiveness of the washer is not adversely affected by operation at the higher wet-bulb tem perature. The analysis of the process occurring in the washer itself is the same as that explained under Method 1. The final desired conditions are secured by adjusting the amount of preheating to give the required wet-bulb temperature at the entrance to the washer. Method S. Even if the heat is added to the spray water, the mixing occurring in the washer itself may still be re garded as adiabatic. The state point of the mixture should move in a direction determined by the specific enthalpy of the heated spray as explained in Chapter 3. It is possible, by elevating the water temperature, to raise the air temperature, both dry-bulb and wet-bulb, above the dry-bulb tempera ture of the entering air. In each of the methods, 1, 2, or 3, the air leaving the air washer may require reheating to produce in the conditioned space the required dry-bulb temperature and relative humid . ity. Dehumidrfication and Cooling with Air Washers Lowering of the wet-bulb temperature of an air-vapor mix ture Ban be accomplished by an air washer if the temperature of the spray water is lower than the wet-bulb temperature of the air. Moisture removal is obtained when the spray wa ter temperature is lower than the dew point of the entering air. In these cases the final dry-bulb temperature and rela tive humidity of the leaving air are dependent upon the de sign factors of the air washer. Both sensible and latent heat are removed in the process of dehumidification by cold spray water. Extraction of sensi ble heat occurs during the entire time that the air is in con tact with the spray medium. Latent heat removal takes place as condensation occurs. Therefore, the lower the spray tem peratures, the greater the amount of moisture removal per pound of dry air, all other conditions remaining the same. Where a limited supply of cold water is available, multiple- stage washers may be used to great advantage. In such washers the cool water is pumped through the multiple spray systems in series and counterflow to the air flow. Such an arrangement brings the delivery air in contact with the coldest water, securing a maximum amount of cooling and saving water. . When using cold well water or water from city water mains, care should be used to secure accurate data on the water tem peratures. Table 2 lists some approximate water main aver ages which may be used as a guide but should be verified from local records. This is particularly true with city water main temperatures. In the case of well water temperatures, Fig. 4 shows the approximate temperatures of water to be expected from wells at depths of 30 to 60 ft. - Air washers for dehumidifying and cooling usually have separate recirculating pumps for each washer. These pumps deliver a mixture of cold and recirculated water under the control of a three-way valve. Evaporative Air Cooling and Humidification 595 Table 2 .... Average Maximum Water Main Temperatures* S/of* Oiy d| State Ofy i State City - 6d State Ofr . a. . WdE Birmingham__ 84 80 83 82 80 60 Kans. 78 N. Y. 77 Texas n, Oft 86 85 Conn. D. C. Del. Fla. Ga. 111. Ind. Loa Angeles .. Oakland........... Pasadena......... Pomona........... Riverside......... San Bernardino San Diego........ San Francisco. Bridgeport. .. New Haven__ Washington^- . 80 75 68 80 69 70 82 75 78 72 65 84 71 75 75 66 73 76 72 84 83 77 60 78 Evansville....... Gary................. Indianapolis. Terre Haute. . 73 83 67 59 82 88 75 84 61 82 Ky. La. Me. Md.' Mass. Minn Mo. N. H. N. J. Shreveport.... 88 60 Yonkers............. 70 Boston............. 80 Cambridge. ... 70 Fall River........ 76 68 70 68 N. M. Raleigh.............. Winston-Salem Albuquerque__ A tmn 92 82 65 Flint................. 70 Highland Park. 77 Kalamazoo.... 53 Lakewood......... 82 Pa. Jefferson City. 82 McKeesport___ R. I. 74 S. C. Manchester___ 76 Jersey City___ 63 75 S. D. Term.. Chattanooga__ 79 | Trenton........... Nashville........... 65 84 90 Utah Va. Wash. W. Va. Wis. Prorince Alta. B. C. Ont. P. E. I. Que. 78 Wichita Falls.. 85 Fredericksburg Lynchburg.... Norfolk............ 65 75 73 80 Olym * _ .. 06 Huntington___ 78 car 8y ** 6 ** 64 . Vancouver....... 60 T n/tnn 50 T mntn 63 Charlottetown. 48 78 Quebec............. 68 * Tbc** *vera*e* token from Tmrioas city wstcr main loceifana, with earn eetaal raises aiichtly higher and hjeq rahtes cbown. value* were (applied by E. E. Better. Uutey Company. Some were obtained from City Water Department records. Tito hlthr< raises riven by the varfcm* euthoritim are usually the** listed. . Performance of an air washer, when cooling and dehumidifying, depends upon a number of factors, among which are: (1) Air velocity through spray chamber area. (2) Spray nozzle pressure. (3) Size factor (larger washers are more efficient than smaller oiies). (4) Spray density (gpm/sq ft/spray bank). (5) Water temperature rise. (6) Air wet-bulb temperatures--entering and leaving. (7) Water-to-air weight ratio. (8) Water temperatures--entering and leaving. (9) Length of air washer in direction of flow. (10) Number and arrangement of spray banks. Where increase of overall heat transfer between the air 596 CHAPTER 41 1959 Guide Fig. 4 .... Approximate Well Water Temperatures at Depths of 30 to 60 Ft1 and water is required, multi-stage washers are used. These washers are equivalent to a number of washers in series, and the water has to be pumped from one stage to the other in a direction counter to the air flow. The most common air washer arrangement for cooling and dehumidifying air has two spray banks and is eight to nine feet long. If the air washer has ability to cool and dehumidify the entering air to a wet-bulb temperature equal to the leav ing water temperature, it is convenient to assign to such a washer a performance factor of 1.0. .The actual performance factor of any washer is the actual enthalpy change divided by the enthalpy change in a washer of 1.0 performance fac tor. Calculation of the required performance factor, FP, for any washer application involving cooling and dehumidifying can be made from Equation 2: F? = (Ai - A,)/(A, - A*) (2) where hi = Enthalpy at entering air wet-bulb temperature, Btu per pound. At ** Enthalpy at leaving air wet-bulb temperature at actual condition, Btu per pound. At -- Enthalpy at wet-bulb temperature leaving a washer with Fr 1.0, Btu per pound. Knowing the performance factor of a particular air washer, the actual conditions of operation can be graphically de termined as shown in Fig. h. Points l and 2 are plotted on the saturation curve representing total heat at the entering and leaving air wet-bulb temperatures, ti and t,'. Point 5 represents the condition at .which leaving air wet-bulb and leaving water temperatures would be the same. This point is determined by solving Equation 2 for the unknown quantity, K. A diagonal line is drawn through Point 5 with a negative fig. 5 .... Graphical Solution of Conditions Produced by an Air Washer Evaporative Air Cooling and Humidification slope equal to the water-to-air weight ratio. Points 3 and 4, at which this diagonal line intersects horizontal lines through points 1 and 2, show the required entering and leaving water temperature t0l and A check of the solution can be made from the fundamental heat balance equation, Heat absorbed by the water = heat removed from the air. The graphical method as described can be used to arrive quickly at solutions of air-washer cooling and dehumidifying problems where there are a number of unknown factors, in cluding quantity of water to be used and the entering and leaving water temperature. It can be adapted to problems of heating and humidifying as well as to water cooling (indoor washer-cooling tower) and multi-stage applications. The actual performance factor of a particular washer must, however, be obtained from the manufacturer's data and de pends on the many factors listed previously. Control of Air Washers Chapter 43 discusses methods of controlling air washers to meet system or space requirements. EVAPORATIVE AIR COOLING Evaporative air cooling is undoubtedly the oldest method ` used in mao's attempt to produce comfort in hot climates. In pre-biblical times,** *4 wetted grass mats and porous jars utilized the evaporative process to cool air or water. The ' early settlers of Southwestern United States found the In dians using these same devices. In the 1930's a rush of in ventions appeared which mechanized evaporative cooling and various devices were developed and manufactured to utilize evaporation directly in the air stream or indirectly to coot the air in a heat exchange proces. Evaporative air cooling equipment may be placed in two general classes, direct and indirect. The first of these uses pri mary wet surfaces which evaporate water directly into-the fresh air supplied to the space being cooled. This may be done with a series of sprays as in an air washer or by use of an extended wetted surface material such as aspen wood excel sior, glass fibers, metal wire, or expanded paper. As these de' vices are relatively simple and economical, they represent the vast majority of equipment in use today. The second class of evaporative air cooling is termed in direct. The indirect cooler uses_the evaporative principle to cool air or water in a device similar to a cooling tower. The resultant cool air or water is then used by means of a second ary heat exchanger to cool the air in the occupied space. The amplest form of this consists of a cooling tower, a circulating pump, and a chilled water coil. The pump circulates the chilled water from the cooling tower sump through the blast coil in the building ventilating system. More complex ar rangements of this principle have been used. By applying recirculating, regenerating principles, temperatures below the initial wet-bulb may be produced.* * The complexity and cost of these devices has made them relatively obsolete with the advent of economical refrigeration equipment. Types of Primary Wet-Surface Evaporative Cool ing Equipment Currently, the drip or desert-type coolers (see Fig. 6) con stitute the largest percentage of evaporative coolers. These devices use evaporative pads, usually made of aspen wood fibers, and a water circulating pump to lift the sump water 597 Bg, 6 .... Typical Drip-Type Evaporative Cooler fig. 7.... Typical Sproy-Type Evaporative Cooler 598 CHAPTER 41 1959 Guide up to a distributing system from which it runs down through the pads and back into the sump. A fan (usually included within the unit) pulls the air through the evaporative pad and delivers it to the space to be cooled. . The spray-type cooler (see Fig. 7) contains an evaporative pad usually made of glass fiber, a water slinger, a centrifugal vaporiser, or spray noszles to throw a fine spray into the air stream and the evaporator pads. Eliminators are usually re quired on the downstream side of the evaporator pads. These devices are supplied with or without the air-handling fan. The rotary-type cooler (see fig. 8) is a device which con tinually wets and washes the evaporator pad by rotating it through a water bath and into the air stream. The evapora tor pads are usually of copper wire construction to provide the necessary structural and corrosion resistance. The air washers previously discussed in this chapter are also used for direct evaporative cooling. ' . Control of sump water within these evaporative coolers consists of a float valve for level control and a bleed-off de vice. Overflow stand pipes, automatic valves or recirculating - pump bypass connections are used for bleed-off. An evapora tive air cooler operating with an efficiency of 80 percent is generally considered optimum. In this case, efficiency is the same as humidifying or saturating effectiveness found from Equation 1. percent outdoor air basis. The air quantity handled by a - typical evaporative cooling system is higher than with re frigerated cooling or heating systems. These relationships can be seen by comparison of Example 1 with the sample air conditioning cooling load calculation, Example 11 of Chapter 13. Example 1: An evaporative cooling system is to be installed in the one-story office building shown in Fig. 6 of Chapter 13. Outdoor design conditions are assumed to be 95 F dry-bulb and 65 F wet-bulb. The heat gains, calculated in Example 11 of Chapter 13, which are used in the design of this type of system are: All walls, roof and doors - Glass areas Occupants lighting 78,500 Btu/hr 5,970 17,000 62,700 Total sensible heat load *= 164,170 Btu/hr Find the required air quantity, the temperature and humidity ratio of the air leaving the cooler (entering the office), and the temperature and humidity ratio of the air leaving the office. Solution: A temperature rise of 10 F deg in the cooling air is assumed. Equation 20 from Chapter 13 may then be used to cal culate the air volume required to be supplied by the evaporative cooler: Design Considerations Various methods for designing evaporative cooling systems are in common use. Simplified rule of thumb methods use an assumed air change rate as a basis. Good engineering practice requires an evaluation of the building heat gain, internal loads, and the cooling season wet-bulb temperature pattern. The suitability of evaporative air conditioning for a par ticular application is, in the first instance/determined by the climatic conditions. The lowest temperature theoretically attainable with the most common systems of the direct or single-stage type is that of the wet-bulb temperature of the entering air. The process is one of adiabatic saturation and in practice is almost always operated with 100 percent outdoor air. Since the lowering of the dry-bulb temperature of the air during the evaporative process is always accompanied by a corresponding increase in moisture content, it follows that the greatest application, of evaporative cooling for con ditions for human occupancy, is in areas in which periods of high temperature are always accompanied by low outdoor relative humidities. The areas in which the climate is suit able for the reliable production of optimum comfort condi tions by evaporative cooling are limited. Despite this, evap orative air conditioning is extensively used over areas with less favorable climates as a means of improving conditions for human occupancy. It finds wide application also in in dustrial applications, particularly in those in which an im provement of dry-bulb temperatures can be used to advan tage, and in which high humidities are desirable or at least not objectionable. Proper analysis of the cooling season climatic data is most important. The most acceptable approach appears to be based on an analysis of the average high wet-bulb tempera tures of the area for the periods when cooling is needed. Cri teria established on this basis must, of necessity, take into account the extent to which departures from optimum condi tions both in degree and duration can be tolerated.- There is no latent heat load on evaporative cooling equip ment as with refrigeration cooling, since it operates on a 100 Qr L080i - Q 164,230 15,200 elm L08 X 10 where Qr. = required air quantity through equipment, cubic feet per minute. q, instantaneous sensible heat load, Btu per hour. U " indoor air dry-bulb temperature, Fahrenheit. t, " room supply air dry-bulb temperature, Fahrenheit. This air volume rate represents a 2.6 minute air change for a building of thin size. The evaporative air cooler is assumed to have a saturating effectiveness of 80 percent. This is the ratio of reduction of the dry-bulb temperature to the wet-bulb. The dry-bulb tem perature of the air leaving the evaporative cooler is found from Equation 3: t, - ti - e4(l. - t') (3) For the conditions of this problem Equation 3 becomes: tt 95 - 0.8(95 - 65) I, - 71 F The humidity ratio of the cooler discharge W, is found from the psychrometric chart Wt = 0.01185 lb per lb dry air. Equation 8, Chapter 13, may be adapted to solve for the remaining unknown, the humidity ratio of the air leaving the space being cooled W,, from Equation 4: q. - Qr* X 4840(FF. - Wt) (4) where q, = latent load, Btu per hour. Qn *= rate of entry of air to the space from the cooler, eubic feet per minute. Evaporative Air Cooling and Humidification 599 The humidity ratio of the air leaving the space, Wt, from Equation 4, is therefore: X 4840 The only latent load of the space for this design is the occupancy load, 21/250 Btu/hr as calculated in Example 11 of Chapter 13. Substituting this and the other known quanti ties in Equation 4: W, - ----- + 0.01185 - 0.01214 Ib/lb dry air. 15200 X 4840 ' The remaining values of wet-bulb and relative humidity for the problem may be found from the psychrometric chart. Fig. 9 illustrates the various relationships of the outdoor air, supply air to the space, and the discharge air. fig. 9____ Conditions Within Evaporative Cooler and Cooled Space for Example I ' The design of evaporative air-cooling systems is similar to other heating or cooling systems. It should be kept in mind that considerably more air will be handled as no recircula tion is used and, therefore, duct, fan, and grille sizes will be larger. This problem has been solved in a number of ways. Large, open buildings such as-supermarkets have been suc cessfully cooled and heated by the use of four evaporative air coolers for cooling, two of which are fitted with duct heaters for space heating. In this way a balance between the summer cooling and winter heating air quantity is obtained. In cli mates which are not particularly suited to direct evaporative air cooling, a combination of refrigeration and evaporative cooling may be economical. There are many industrial demands for cooling where direct evaporative cooling is economical. Successful applica tion of this type has been made for electric-motor cooling, tiixbine cooling, and spot cooling in the factories such as tex tile mills, steel mills, and foundries. Laundries, with their large exhaust air loads, may also take advantage of evapora tive cooling. In cattle and poultry barns evaporative cooling kfs been used with excellent results even in climates which give poor results with human occupancy. This is possible be cause the blood temperature of these animnln is higher than human/ Greenhouses use evaporative cooling to reduce tem perature and raise humidity. Two Stage Evaporation /Ur Cooling . On industrial or commercial installations two stage evap orative cooling will sometimes be found to be effective and economical. Such a system uses a cooling tower and a blast coil ahead of the evaporative air cooler. Using & 6 or 8 row coil and a well designed cooling tower, the air discharged from' the blast coil can be within 15 F of outdoor wet bulb. This part of the cooling takes place at constant humidity ratio. Passing the cooled air through an evaporative air cooler fur ther reduces the dry-bulb temperature, the process following the thermodynamic wet-bulb temperature line on the psy chrometric chart. Use of this two stage system will result in smaller required air quantities and consequent low duet costs. Careful design can frequently allow the same duct and grille system to be used for heating and maintain proper duct and register velocities. - Control of Evaporative Air Coolers Control of evaporative air-cooling systems may be accom plished by ordinary dry-bulb thermostats or a combination of a dry-bulb thermostat and a humidistat. These controls are set to turn on at a dry-bulb temperature and off at a pre-set high humidity. When two-speed fans are used, auto matic control of fan speed may be employed to provide bet ter control results. Evaporative air-cooling systems can also be used for ven tilation on mild days and at night when air temperatures are relatively low and straight ventilation produces comfortable results. A valve on the water supply to the evaporative air cooler may be operated by a thermostat in the outdoor air to accomplish this automatically. See Chapter 43 for general information on controls. Maintenance Much of the discussion of maintenance and operation prob lems at the end of Chapter 40, Evaporative Apparatus for Heat Rejection, is pertinent to evaporative air cooliDg and humidification equipment as all these devices use the evapora tion of water as the cooling mechanism. Some air washers and all evaporative air coolers contain ex tended surface, evaporator pads of one sort or another. Be cause of these pads, control of the scale-forming mineral con tent of the water is required or the extended surface pads will soon plug up with scale and the air flow will be reduced. Another effect of scale deposit is to cause rhannoiing of the water and air and so give local high velocities and consequent entrainment. Some scale will be deposited on these pads dur ing drying after shut-down. If replacement or cleaning is re quired more frequently than once a year the scale control method is usually at fault. Chemical water treatment with polyphosphates is helpful to prevent hard scale. Regular blowdown or bleed-off of sump water is usually the best con trol to prevent corrosion and hard scale deposit. . REFERENCES 1 W. D. Collins: Temperature of water available for industrial use in'the United States ((/. S. Geological Survey Water Supply Paper No. 520 F). 'Air conditioning in Iran (Heating and Ventilating, June 1947, p. 93). *D. L. Fiske: Refrigeration is not new (Refrigerating Engi neering, October 1932, p. 201). `George Cecil: Keeping cool in India (The Heating and Ven tilating Magazine, June 1927, p. 61). 600 CHAPTER 41 1959 Guide *K. P. Brace: Regenerative cooling for hot, dry climates (Beating and Ventilating, May 1932, p. 36). J. R. Watt and R. A. Bacon: Indirect evaporative air cooler (Heating, Piping and Air Conditioning, May 1956, p. 149). ' R. 8. Ash: Evaporative cooling for farm miimnla (Air Condtiioning. Heating and Ventilating, October 1956, p. 109). BIBLIOGRAPHY H. M. Hendrickson: How air washers perform when cooling (Heating, Piping and Air Conditioning, March 1954, p. 119). H. M. Hendrickson: How to calculate air washer performance when cooling (Heating, Piping and Air Conditioning, Septem ber 1954, p. 116). T. W. Reynolds: Evaporative cooling in air conditioning ap plications (Heating and Ventilating, March 1944, p. 53). F. W. Hutton: Useful tool--properly engineered evaporative cooling (Heating, Piping and Air Conditioning, July 1950, p. R. S. Farr: Evaporative cooling for comfort (Refrigerating Engineering, May 1953, p. 527). M. H. Irons: Evaporative-cooling for textile management (Mechanical Engineering, February 1943, p. 115). ' G. T. Lang: Evaporative cooling for textile mills (Heating and Ventilating, December 1945, p. 89). W. L. Fleisher and J. H. Binges: Air conditioning the textile mill (Refrigerating Engineering, May 1954, p. 33). W. L. Fleisher: Evaporative cooling for comfort (Refrigerat ing Engineering, December 1936, p. 406). R. S. Ash: Cooling industrial hot spots with evaporative cool ers (Heating, Piping and Air Conditioning, December 1655, p. 94). . R. 8. Ash: Summer cooling for greenhouses (Air Condition ing, Heating and Ventilating, August 1957, p. 67). Evaporative Cooling--A Symposium (Presented at ARTTAW 1955 Semi-Annual Meeting). CHAPTER 42 DEHUMIDIFICATION BY SORBENT MATERIALS Types of Sorption Dehumidifiert; liquid Sorption Systems: Liquid Sorbents, Machine Operation and Design; Solid Adsorption Systems: Soil'd Desiccants, Machine Operation and Design; Sorption Dehumidihers for Elevated Pressures; Applications for Sorption Dehumidifiert; Moisture Load Calculations; Vapor Transfer to Dehumidified Space EHTJMIDIFICATION as used herein is the reduction 3. Stability. It should not break down over the range of use. D of the water-vapor content of a given volume of air or 4. Low viscosity and good heat-transfer characteristics. other gas. The term thus describes a special case of de 5. Widely available and economical to produce. hydration which covers the removal of moisture in any form 6. Capable of being regenerated at temperatures obtainable with low-pressure steam. . from matter. The degree of dehumidification required varies greatly with different applications, and is one of the prime The equilibrium contact dew point is plotted against con considerations influencing the choice of a method. tact temperature for various concentrations of .a typical Dehumidification may be accomplished by chilling, as organic liquid absorbent in Fig. 1. The same data for a described in Chapters 19, 23, and 41, by the use of sorbents, typical inorganic absorbent is shown in Fig. 2. The concen or by compression in combination with chilling, sorbents, or tration of the liquid absorbents used in commercial equip both chilling and sorbents. ment is dependent on the temperature of the cooling medium, ` Sorbents are substances which have the property of ex and on the latent and sensible heat-removal requirements. tracting and holding other substances (usually gases or The equilibrium contact dew points in Figs. 1 and 2 show vapors, eg., water vapor) brought into contact with them. the dew point of air in equilibrium with the liquid absorbent. All materials are sorbents to a greater or lesser degree. The Reference should be made to the published performance weight of water held by a substance will increase or decrease, data for commercial apparatus for the solution of air-con depending upon whether the vapor pressure-of the water ditioning and air dehumidification problems, fig. 3 shows a held by the substance is les or greater, respectively, than rating curve for a liquid absorbent dehumidifier using lithium the partial presure of water vapor in the surrounding atmos chloride solution. phere. As generally used, however, the term sorbents refers to those materials having a capacity for moisture which is - Liquid Absorption Operation large compared to their volume and weight. Such materials are divided into two general classifications: The operating cycle of a liquid absorption system with ex tended-surface contactor coils is shown by Fig. 4. For de 1. Absorbent--A sorbent which changes either physically, chemically, or both, during the sorption process. Calcium chloride is an example of a solid absorbent, while liquid absorbents include solutions of the halogen group (lithium chloride, lithium bromide), and the ethylene glycols. 2. Adsorbent--A- sorbent which does not change physically or chemically during the sorption process. Certain solid ma terials, such as activated alumina;-silica gel, activated bauxites, and activated charcoal have this property. The action of ad sorbents, most of which adsorb some gases and condensible vapors besides water vapor, is selective. Thus, in the case of a mixture containing both water and organic vapors, silica gel would remove the water vapor in"preference to the organic va pors, while the reverse would be true in the case of activated carbon. The selective property of adsorbents is made use of in some instances for the removal of objectionable and contami nating vapors from an air or gas mixture. (See Chapter 7.) LIQUID ABSORPTION SYSTEMS humidifying operation the strong absorbent solution is pumped from the sump of the unit and sprayed over the contactor coils. . The hygroscopic solution at the required temperature and concentration is in intimate contact with the air which is flowing over the coil surface in the same direction as the liquid absorbent. Equipment is also available for flow counter current to the flow of liquid absorbent. Moisture is absorbed from the air by the solution due to the vapor-pressure dif ference between the air and the liquid absorbent. The mois ture content of the outlet air can be maintained at a constant condition by automatically regulating the flow of water through the cooler with a modulating water valve. The heat generated in absorbing moisture from the air is called the heat of condensation of the water vapor in the solution. This consists of the latent heat of condensation of Liquid Absorbents . water vapor and the heat of solution or the heat of mixing. The heat of mixing varies with the liquid absorbent used A liquid absorbent has the property of absorbing moisture and with the concentration and temperature of the absorbent. from, or adding moisture to, the air, depending upon the The solution is maintained at the required temperature by vapor-pressure difference between the air and the solution. cooling with city, well, refrigerated, or cooling tower water, The equilibrium vapor pressure of the solution is dependent or refrigerant flowing inside the tubes of the contactor upon the temperature and concentration of the solution. coil. The quantity of water required is a function of the Absorbents for a liquid dehumidifying system should have water temperature and the total heat, eitheT sensible, latent, the following characteristics: ** . or both, removed from the air by the hygroscopic solution. 1. Suitable vapor-pressure characteristics. The absorbent . should not crystallite at temperatures 10 to 15 deg below the temperature range used in the operating cycle. The dry-bulb temperature of the air leaving the liquid absorbent contactor is a function of the temperature of the liquid absorbent and the amount of contact surface between 2. Noncorroeive, odorless, nontoxic, and nonflammable. the air and the solution. In most commercial equipment the 601 602 o CHAPTER 42 *IIABL WMTCR 1959 Guide fig. 1.... Temperature--Equilibrium Dew-Point Char* * oderistics for Typical Organic Absorbent. dry-bulb temperature of the air leaving the dehumidifier will be within 1 to 5 deg of the liquid absorbent temperature. Cooling and healing coils are installed in the ductwork after the dehtimiHifor if the air is to be cooled or heated. The liquid absorbent is maintained at the proper concen tration for moisture removal by automatically removing from the liquid the water vapor absorbed from the air. A small percentage of the solution, usually 10 to 20 percent of the flow to the contactor coils, is passed over the regenerator coil where the liquid is heated with steam or other heating medium. The liquid absorbents commonly used may be re generated with steam at 2 to 25 psig. The vapor pressure of the liquid absorbent at temperatures corresponding to. 2 Rg. Z.... Performance Data for Liquid-Absorbent Dehumidifier Using Lithium Chloride . psig steam is considerably higher than that of the outdoor air. The hot solution at the relatively high vapor pressure is- in contact with outdoor air in the regenerator where water is absorbed from the solution by the scavenger air due to the vapor-pressure difference between the outdoor air and the hot solution. The hot-moist air from the regenerator is dis charged to the outdoors and the concentrated solution flows to the sump where the process is repeated. The steam flow to the regenerator coil is regulated by a control responsive to the concentration of the solution circu lated over the contactor coils. This may be a Level control, specific gravity control, boiling point control, or a similar instrument. For humidifying operations the liquid absorbent is main tained at the required temperature by adding heat in proportion to the water absorbed by the air from the solution. Water is automatically added to the solution to maintain the proper concentration. _ SOLID ADSORPTION SYSTEMS Solid Desiccants The ability of an adsorbent (desiccant) to remove water vapor from a gas is explained by the fact that the vapor pressure of the water in the adsorbent (when in the re- CONOITIONCD AIR OUT SOWENOCR AIR OUT fig. 2.... Temperature--Equilibrium Dew-Point Char acteristics for Typical Inorganic Absorbent Dehumidification by Sorbent Materials 603 activated condition) is less than the partial' pressure of the water vapor in the surrounding atmosphere. For instance, when an active adsorbent is brought into contact with a gas of high humidity, there is a tendency for the -vapor pressure of the water in the adsorbent to reach equilibrium with the partial pressure of the water in the surrounding gas, with the result that water is extracted by the adsorbent and its weight increased, while the moisture content of the gas is correspondingly reduced. (The adsorbent is said to be saturated for a given condition when equilibrium is attained.) The weight of water a given adsorbent will extract is de pendent upon the relative humidity (ratio of toe partial pressure in the gas to the saturation pressure at a given tem perature) and the temperature of the adsorbent. The process is reversible; if the temperature of the adsorbent is raised until the vapor pressure of the adsorbed water becomes greater than the partial pressure of -toe vapor in the sur rounding atmosphere, water will be released by the adsorbent. After the adsorbent cools to room temperature, for instance, the vapor pressure of the water in the adsorbent falls below the partial pressure of the vapor in the atinosphere, and the adsorbent will again start extracting water. The elimination of water by the addition of heat is known as reactivation, and is a means of regenerating the adsorbent so that it may be used repeatedly. Adsorption is proportional to the amount of surface (in ternal and external) of the sorbent. The materials th.fc are used commercially as solid adsorbents have a porous structure of submicroscopic dimensions, which gives extensive surface area. An adsorbent should meet the fol lowing requirements in order to be satisfactory for de humidification purposes: -- 1. Have a high adsorptive capacity under normal atmospheric conditions. . 2. Be chemically stable, resisting contamination from im purities. ' 3. Be physically rugged to resist breakdown from Hunititng and use. . 4. Be capable of reactivation at temperatures generally ob tainable. -. . 5. Be heat-stable at reactivation temperatures. 6. Have a weight per unit volume such aa to avoid excessive bulk. 7. Be available at reasonable cost. There are a number of soU4. adsorbents available, which are used in solid adsorption systems. The reader is referred to the various manufacturers for detailed information re garding performance of the various desiccants. These in clude activated aluminas and - bauxites, silica gels, and alumino-silicates marketed under various trade names. Re activation temperatures for these desiccants are generally between 200 and 600 F. Machine Operation and Design Dehumidification by a solid desiccant such as silica gel or activated alumina may be performed either under static or dynamic operation. As the name implies, toe static method entails no artificial means for circulating the gas to be dried into or through the desiccant. Instead, the air im mediately surrounding the adsorbent is initially dried and subsequently, through convection and diffusion, water vapor from spaces and objects further away pass into toe air sur rounding the desiccant and then to the desiccant where it is. adsorbed. Obviously this type of de>iTnidifi^R.tjf>ri is best suited for small containers. This method of preservation was used extensively by the armed services during World War II for overseas shipments and domestic storage. On the other band, dynamic dehumidification entails the forced passage of the air being treated through the desic cant bed. This method is used in installations such as de humidified warehouses and ships of the "Mothball Fleet" where large volumes of air must be dried. 'Hie only requisites for a dynamic dehumidifier are a desiccant bed, a fan to force the humid air through this bed, and a heater to periodically reactivate the adsorbent. As the air passes into the activated desiccant, it surrenders a certain amount of its water vapor. The rate of moisture pickup and the humidity condition of the leaving air are functions of a great many variables, some of which will be discussed later. The ratio of the amount of water adsorbed by the desiccant in a given time to the amount of water vapor in the air entering the desiccant bed during that time is known as adsorption efficiency. A characteristic of ad sorbents in dynamic use is that this adsorption efficiency remains constant and at a relatively High level from the beginning of an adsorption cycle until some later point in the cycle at which time the efficiency begins to drop. This 'point is known as the break-point, and the time from the beginning of adsorption to this point is known as the break point time. In the ideal case the breakpoint would coincide time-wise with the sudden rise in the dew-point temperature of the effluent air. Although additional drying can be ef fected beyond the breakpoint, good commercial practice dictates that the desiccant be regenerated at or near this point. Adsorption carried beyond the breakpoint continues at an increasingly slower rate until the adsorbent is com pletely saturated. This point is known as completion. Adsorbents, such as silica gel and activated alumina, contain, even when reactivated, a small amount of water. This is usually about 5 to 7 percent of the dry weight of the desiccant and is known as residual moisture. Attempts ' to remove it result in a physical change in the substance and a reduced adsorptive capacity. The term useful con centration is used to designate the percent of moisture in the adsorbent over and above the residual quantity. It is generally based on the dry weight of the desiccant. When regeneration of the adsorbent is desired, the heater is energised and the direction of air flow through the bed is usually reversed. The dry-bulb temperature of the ef fluent air rises rapidly at first, and then virtually levels off for a period of time. This period of level or slowly incragging temperature represents the period during which the major portion of the heat input is bang used to boil off toe ad sorbed water. This temperature pattern continues until most of the water contained in or on the desiccant is re leased. When the latent heat requirements begin to Himinigh, the heat input goes into sensible heat gun to the passing air stream. This is reflected in a rather sharp increase in the drybulb temperature of the effluent air. This period, measured from the beginning of desorption, has been designated tem perature-rise time. Although additional regeneration (at a slower rate) can be attained by continuing toe heat ad dition process beyond the temperature-rise time, once again good commercial practice calls for reactivation to be ended near this point. Regeneration past this point until the ad sorbent is in moisture equilibrium with the air stream is known as complete desorption or desorption to completion. The energy expended in the heater per unit weight of water desorbed for any given time is called economy of. desorption and usually has the dimensions of kilowatt hours per pound of water desorbed. 604 CHAPTER 42 1959 Guide fig. 5....Silica Gel--Water-vapor Equilibrium Curves During the process of adsorption there is a liberation of beat which results in an elevation of the effluent air temperature. This heat is equivalent to the latent heat of vaporization of the adsorbed liquid plus an added quantity known as the heat of wetting, which is defined as the heat developed when a liquid and a solid surface contact one another. As the adsorbed vapor condenses, the latent heat is converted to sensible. All of the released beat, known cumulatively as the heat of adsorption, is dissipated into the desiccant, the enclosure, and the passing air stream. In comfort air conditioning it is often necessary to cool this effluent air prior to its introduction to the conditioned space, but in most other dehumjdification applications this heat is not objectionable, and no provisions are made for its re moval. For this reason the process is known as adiabatic adsorption, meaning that the released heat is taken up for the most part by the passing air stream, that the adsorbent chamber is insulated, and that no attempt is made to cool the effluent air. Although ordinary air-conditioning dehumidifica tion only approaches the adiabatic process, it is called adia batic to differentiate it from the isothermal adsorption proc ess in winch the outlet gas is cooled to inlet temperature. It is appropriate now to discuss the factors which influence the rate and amount of water-vapor adsorption by the desiccant. Although such factors as the shape and volume of the desiccant pores and the surface tension and wetting ability of the condensed vapor are important, the foremost considerations when working with a given adsorbent and a given vapor, for example, airborne water vapor, are the temperature of the adsorbent and the dry-bulb and dew point temperatures of the air. The latter temperature is important since it is a function of the partial pressure of the water vapor in the air. The relationships existing be tween these variables are best illustrated by the Silica GelWater-vapor equilibrium curves shown in Fig. 5. In this set of curves, silica gel and air temperature versus percent water in silica gel (dry weight basis) form the abscissa and ordinate, and air dew-point temperatures (with the cor responding vapor pressures) are the parameters. Several important characteristics of the adsorbent are brought out by these curves. For example, note that each of the curves becomes asymptotic to the X-axis somewhere'"between 5 and 6 percent moisture content. This is because, under normal reactivation temperatures, there is always thri amount of water in the gd. Known as residual moisture, it is omnipresent and an attempt to remove it results in a physical change in the desiccant and a reduced adsorptive capacity. The term useful concentration is used to desig nate the percent moisture in the gel over and above the residual-amount. The variation in this useful concentra tion during a test measures tbemagnitude of adsorption or desorption since the residual amount theoretically remains unchanged Assuming no excessive activation temperatures. Note that at constant air and gel temperature the amount of moisture adsorption varies directly with the air dew point temperature, i.e., as the air approaches saturation con dition (dry-bulb temperature equal to dew-point tempera ture) the equilibrium moisture content of the gel increases. It can also be seen that at saturation the percent water in the gel is in the neighborhood of 40 percent of the dry weight of the gel for all temperatures. ' With a fixed dew-point temperature, the moisture con centration decreases as the temperature of the air and gel is increased. Some of the many variables that influence the results of a dynamic dehumidification operation are: 1. Type of desiccant. 2. Grain size of desiccant . 3. Shape of bed. 4. Area of bed normal to air flow. 5. Depth of bed. v 6. Dry weight of desiccant. 7. Packing of the desiccant in the bed. 8. Weight of air Sowing per unit of time. 9. Temperature of entering air. 10. Moisture content of entering air. 11. Contact time between air and adsorbent; a function of inlet face velocity and bed depth. . 12. Barometric pressure. 13. Pressure drop through bed. 14. Duration of cycles. 15. Reactivation temperature. ' 16. Rate and magnitude of heat supply during reactivation. 17. Heat storage capacity of. the bed. 18. Temperature gradient of the bed. 19. Air leakage from the apparatus. Solid adsorption dehumidifiers are mostly of the stationary dual-bed type in which one desiccant bed is adsorbing while the other is being reactivated by electricity, gas, or steam. Dehumidification by Sorbent Materials . Fig. 6 shows a schematic flow diagram for a typical dual bed dehumidification unit. There are two types of units: (a) Shallow-bed; (6) Deep-bed. Shallow-bed machines have comparatively thin desiccant beds and moisture removal is not complete in one pass through the bed. Low dew points may be maintained by progressive lowering of the room dew point as increasingly drier air enters the machine. The machine capacity must be in excess of internal moisture load and infiltration of moisture from external sources. Increased dryness can be obtained by reducing outlet air flow and recirculation of ex- ces air from the dry air outlet to the humid air inlet on Am OUTLET 605 BCD A DRYING BCD e REACTIVATING BCD A REACTIVATING BCD B DRYING Fig. 6 .... Typical Dual-Bed Dehumidificafion Unit Air-Row Diagram fig. 7.... Typical Cycle Diagram for Shallow-Bed - Dehumidifier G. -- moisture content of air leaving dehumidifier, grains ' . of moisture per pound of dry air. . s ** specific volume of the air, cubic feet per pound. 7000 * conversion from grains to pounds. Moisture removal capacity may be increased by (1) higher inlet dew point; (2) for a constant entering dew point; lower temperature and greater saturation; (3) larger .air quantity, which causes a decrease in the dryness of the effluent air. If the air to be dehumidified is very warm, and especially where a very low dew point is required, it is advantageous to install a precooler to reduce the temperature of the inlet air. In this way the working temperature in the adsorber is lowered, and the overall performance appreciably increased. Some equipment manufacturers install cooling coils in the adsorbent beds for the same purpose, while others divide the adsorbent bed and install coolers between the sections. tiie machine. Fig. 7 shows a typical cycle diagram for a shallow-bed machine. Deep bed machines have desiccant beds 10 in. and more in depth. Deep bed units are used when extreme dryness is required in one pass through the dehumidifier and the air cannot be recirculated. Fig. 8 shows a typical cycle diagram for a deep-bed dehumidifier. Most fixed-bed machines work on a predetermined time cycle. Smaller machines usually have a nonadjustable cycle. Larger units have adjustable time cycles that can be changed for various operating conditions. The average hourly moisture removal capacity of a de humidifier can be determined as follows: GOQiOi - O.) 7000? (i) where W = moisture removed, pounds per hour. Q air volume, efro. 60 * conversion of cubic feet per minute to cubic feet per hour. Gi e* moisture content of air entering dehumidifier, grains of moisture per pound of dry air. fig. 8 .... Typical Cycle Diagram for Deep-Bed Dehumidifier 606 CHAPTER 42 1959 Guide PARTS OP MOISTURE PCR MILLION PARTS ORY AIR BY VOLUME Rg. 9.... Moisture Content of Air at One Atmosphere Pressure . Fig. 9 shows the moisture content of air at one atmosphere pressure. SORPTION DEHUMlDIFtERS FOR ELEVATED PRESSURES The same sorption principles which pertain to low-pres sure (approximately atmospheric) dehumidification apply to drying of high-pressure air, process gases, etc. The sorbents described previously can be used with equal effectiveness. . Equipment Avcgn may vary considerably in detail,, but most basic adsorption units utilize dual bed construction for continuous operation and either internal or external heat source with air or process gas as reactivation purge for liberating previously adsorbed moisture. A single ad fig. 10.... Typical Performance Data for Solid Sorption Dehumidifiers at Elevated Pressures sorbent bed may be used for intermittent drying require ments. Absorption units are generally constructed in the same manner as atmospheric pressure units, except that they are enclosed in vessels suitable for the operating pres sure. Either compressing of the gas to be dehumidified or pre cooling by water, brine, or refrigeration will reduce the total moisture load to be handled by the sorbent permitting use of smaller drying units and permitting lower dew-point performance. The performance of the complete system con sisting of precooler and adsorbent dryer must be investi gated at various temperatures to determine the most eco nomic operating level. Applications include drying compressed air for processing, totting, and instrument use. Drying of air and gases have made many processes possible or effective in the chemical, petroleum, and steel industries. Typical performance data for solid sorption dehumidifiers for pressures up to 200 prig are shown in Fig. 10. - A dew-point conversion chart is shown in Fig. 11. This chart is of value to determine changes in air dew points due to compression or expansion. USES OF SORPTION DEHUMlDIFtERS Sorption dehumidification equipment is used where it is desirable to control the removal of moisture from the air independent of the dry-bulb temperature of the air. Such a procedure is required in many industrial processes where the relative humidity must be controlled during the manu facture and preservation of the product. In comfort air-conditioning dehumidification, with cooling, may serve advantageously under certain design conditions Dehumidification by Sorbent Materials 607 such as high moisture load in comparison to sensible heat load, high ratio of fresh air to recirculated air, and in ternal load variation. Liquid absorbent dehumidification, in combination with refrigeration, is applied in industrial areas requiring either dew-point or dry-bulb temperatures below the freezing point of water, eliminating the formation of frost or ice on refrigeration coils. This particular function is illustrated by its use in wind tunnels to produce dew points as low as --60 F. It is also employed in low temperature process tunnels and chill rooms. Other applications include supplying dry air to prevent condensation of moisture on cold surfaces, dehumidification of warehouses ot storage rooms for military supplies as well as certain commercial products, and maintaining a dry atmos phere in cargo holds on ships. A more recent development is found in the dehumidification of underground caves. MOISTURE LOAD CALCULATIONS The application of dehumidification equipment to main tain spaces at low dew point requires careful calculation of the internal moisture gain in the room from all sources. The internal moisture gain consists of latent load from the occupants, process load from any products which give up moisture, exposed water surfaces in the space, open gas flame, water-vapor migration through cracks around the doors, windows, and other openings in the room (infiltra tion), and moisture transmitted through the building sur faces. The latent load from people, exposed water surfaces, open gas flame, and moisture transmitted through building surfaces are found in the,appropriate Guide chapters. The internal latent load due to water-vapor transfer through cracks, conveyor dots, and open doors has not been standard ized and is generally calculated by engineers on the basis of judgment and experience. _... Calculation of the dehumidification required to maintain lower than normal,moisture content in a given room huigi-na with determination of the rate of moisture gain in the room from all sources. It is common practice, when maintaining a low humidity ratio, to recirculate a large percentage of the air in the room through the dehumidifier, and to add only enough outdoor air to meet the needs of the problem. The humidity ratio of the mixture of outdoor and recirculated air and the dehumidifier performance data can be used to calculate the humidity ratio of the air leaving the dehumidi fier. The difference between the humidity ratio of the air in the room and that of the dehumidified air entering f-ht> room represents the effective dehumidification per pound of air. The rate of internal moisture gain in grains per minute, divided by the effective dehumidification in grains per pound of air, equals the air quantity required in pounds per minute. The following typical example using arbitrary values shows & general method of determining the dehumidifying require ments. Sensible heat determination considerations are dis cussed in other chapters, and are purposely omitted here. . Bxample 1: A sorption dehumidifier is to be used to maintop indoor conditions of 73 F and 20 percent relative humidity, e., 24.1 grams per pound of dry air, 30 F dew point, in a room aO ft x 30 ft x 10 ft high, having a total wall, ceiling, and floor surface area of 2200 sq ft. Outdoor design conditions are 72 F dew point (118.4 grains per pound). Internal sources of moisture are: 4 occupants; an open nat ural gas burner using 15 cu ft of natural gas per hour; an open top water tank, having an area of 2 sq it exposed surface, in which water is maintained at 87 F, with air movement over the water surface being 100 fpm. Determine the quantity and con dition of the dehumidified air to be supplied to the room. Solution: The internal moisture gain consists of items 1 to 5. Gnin per 1. From occupants: 4 X 1800/60 = 120 1800 grains per person per hour is obtained from Fig. 7, Chapter 6, by interpolation between curves C and D. 2. From burned gas: 15 X 650/60 ** 162 1 cu ft natural gas produces approximately 650 grains of moisture. 3. From exposed water surface: 2 X 20 s 40 - Evaporation from water surface is assumed to be 20 grains per (minute) (square foot) at 87 F water with air movement of 100 fpm. 6000 4. From infiltration: ^ X (118.4 - 24.1) =* 696 One air change, 6000 cu ft, assumed per hour (see Chapter 11). 5. Moisture transmitted through room surface: ^ X 3 X (0.783 - 0.176) - 67 Permeability assumed to be 3 grains per (square foot) (hour) (inch Hg vapor-pressure difference on two sides of wall). Total moisture gun from internal sources 1085 Let o be the air delivered to the room, pounds per minute. Let it be assumed for this problem that 85 percent of the air is recirculated and 15 percent is outdoor air. Enough air must be supplied to replace leakage from the system or to satisfy normal ventilating requirements for the occupants of the room as given in Chapter 6, whichever is greater. The amount is estimated from experience or obtained by test. The humidity ratio of the mixture of recirculated and out door air entering the dehumidifier is then: 0.85?(24.1) + 0.1S?(118.4) 0.85? -f 0.15? = 3&3 grains per pound entering dehumidifier. From the manufacturer's performance data for the de humidifier to be used it is determined that with 38.3 grains per pound of entering air the leaving condition is 6.5 grains per pound. Effective dehumidification in the room is 24.1 -- 6.5 or 17.6 grains per pound of supply air. 1085 grains per minute . ., Then ?* " -1rz7~.z6--g--r-a-i=-n-s-- -p-e-r---p--o--u-n--dy = 61.6 lb air per minute minimum that must be supplied to the room to maintain 30 F dew point. Note that this value represents the minimum requirement for the arbitrary conditions set forth and that in practice, safety margins should be added to the outdoor air percentage value and to the calculated internal moisture gain. VAPOR TRANSFER TO DEHUMIDIFIED SPACE The walls enclosing a dehumidified space are subjected to a vapor-pressure differential. The pressure of the vapor outride the walls tends to force moisture through the walls into the dehumidified zone of relatively low vapor pressure. As this process can be an unnecessary load on the de humidifying equipment, provisions should be made for keep ing the vapor transfer to a minimum. Also, if the space is cooled below the ambient dew point, there is a possibility that condensation may occur within the walls, unless vapor 408 CHAPTER 42 1959 Guide transfer is controlled. For these reasons a vapor harrier should be located within the wall construction as near to the high vapor-pressure side as feasible. To be effective, a bar rier must be continuous and should be so located within,the structure that it will be protected from rupture. (See Chapter 10 Moisture In Building Construction.) . BIBLIOGRAPHY R. C, Amero, J. W. Moore, and R. G. Capell: Design and use of adsorptive units {Chemical and Engineering Progress, Vol. 43, July 1947, p. 349). A full bibliography is included in this article. W. L. Ross and . R. McLaughlin: An analysis method for predicting behavior of solid adsorbents in solid sorption de humidifiers (ASHAE Transactions, Vol. 61, 1955, p. 321). Symposium Bulletin on Dehumidification (five papers pre sented at Symposium held at 63rd Annual Meeting AShAE February 28, 1957). G. C. F. Asker and T. H. Urdahl; Ship Dehumidification Sys tems (International Institute of Refrigeration, Nantes, France, June 20, 1957). Several references included. ' CHAPTER 43 AUTOMATIC CONTROL Fundamentals: Types of Control Systems and Action, System Components, Controllers and Controlled Devices, Auxiliary Control Equipment; Design Coordination: Equipment Selection and Layout; Location of Controllers; Control of Steam, Water, or Air Flow; Zone Control; Control Applications: CentraI fan. Temperature Control in Hot Water Systems, Zoned Steam and Water Systems, Terminal Equipment, Residential Heating and Air Conditioning PRESENT-DAY standards of comfort. combined with its operation on a prearranged relationship between out capacity and rapid response of modern 'heating and door temperature and heat input to the building, and room cooling equipment make automatic controls an essential part temperature has no effect on the controller. of heating, ventilating, and air-conditioning systems. These As there is no feedback, the control corrects only for automatic controls respond to variables such as temperature, those disturbances of room temperature caused by changes relative humidity, and pressure. They operate individually in outdoor temperature. or in sequence to maintain the desired conditionsthroughout the system and in the occupied space. A factor that has , TYPES OF CONTROL SYSTEMS iadft the subject of automatic control somewhat confusing Control systems are divided into five main groups accord has been the matter of terminology. Many different expres ing to the primary source of energy; sions or words have sometimes been used to convey a angle idea or concept. This chapter, therefore, attempts to use and define the terms that are most common and suitable so that they will be readily understood. The terms and definitions used are also selected so as to conform, as nearly as possible, to automatic control terminology used by engineers in other fields of control. PART I--FUNDAMENTALS OF AUTOMATIC ` CONTROL A control system. Fig. 1, consists essentially of (1) a con troller, (2) a controlled device, and (3) a source of energy. A controller is a device which measures a variable condition such as temperature, humidity, pressure, and liquid level, and produces a suitable action or impulse for transmission to the controlled devices. Thermostats, humidistata, and pressure con trollers are examples. . A controlled device reacts to the impulse received from a controller and varies the flow of the control agent. It may be a valve, damper, electric relay, or a motor driving a pump, fan, etc. . The control agent is the medium manipulated by the con trolled device. It may be air or gas flowing through a damper; gas, steam, water, etc., flowing through a valve; or an electric current. The controlled variable is the condition such as temperature, humidity, or presure, being controlled. Most control systems, of which Fig. 1 is typical, form a 1. A self-contained system combines the controller and con trolled device in one unit and employs the power of the meas uring system to effect the necessary corrective action. The meas uring system derives its energy from the process under control without amplification by any auxiliary source of energy, and Sbe of the sealed-bellows or remote-bulb type as described r Types of Measuring Elements. Temperature changes at the bellows or the remote bulb result in pressure or volume changes of the enclosed media which are transmitted directly to the operating device of the valve or damper. 2. A pneumatic system utilises compressed air, usually at a pressure of 15 to 25 psig, as a source of energy. This is supplied to the controller which in turn regulates the pressure supplied to the controlled device. 3. A hydraulic system utilises a suitable liquid under pressure as the source of energy. The pressure often is considerably higher than in a pneumatic system, but in other respects the systems are similar. Hydraulic systems find their chief use in applications where large forces are required for operation of the controlled devices. - ' 4. An electric system utilizes electric energy, either low or line voltage as the energy source. The electric energy supplied to the controlled device is regulated by the controller either directly or through relays. 5. An electronic system also utilizes electric energy, but em ploys an electronic amplifier to increase the minute voltage variations of the measuring element to values required for operation of standard electrically controlled devices. Measuring elements usually are of the resistance type,. but thermo couples also are employed. Combination electronic-pneumatic systems utilize compresed air for operation of the controlled device by converting the output of toe electronic amplifier into closed loop. That is, the controller measures and responds to changes in the controlled variable and actuates the controlled device to. bring about an opposite change which is again measured by the controller. This system of transmitting information about the results of an action or operation back to its origin is known as feedback, and makes true automatic control posable. ' An open-loop system is sometimes employed in control circuits, but it does not provide complete control. An out door thermostat arranged to control the flow of heat to a ` building in proportion to the load caused by changes in outdoor temperature is an example. This system depends for 610 CHAPTER 43 1959 Guide suitable air-pressure changes by means of an electronic-pneu matic transducer. TYPES OF CONTROL ACTION Control action may be divided into five types: 1. Two-position action, Fig. 2, is the type in which the controlled device can be positioned only to a maximum or minimum position, or can be either on or off- A thermostat which opens and doses a valve, or starts ana stops a burner, is an example. ' Fig. 2.... Two-Position Control 2. Timed txoo-positum action is a common variation of twoposition control action in which the time of on periods are prematurely shortened. This type of action usually is employed only in room thermostats, and is accomplished by a heater element in the thermostat which is energised during the on periods. Hie percentage of time on is vaned in proportion to the system load. Controller differential applying to two-position control action, is the difference between die setting at which the controller operates to one position and the setting at which jt operates to the other position. As an example, if a pressure controller starts a pump at 12 psig and stops it at 15 psig, the differential is 3 psi. It is sometimes desirable to have a controller in which the differential can be changed by manual adjustment. This is designated as an adjustable differential. the controller, as is the case with floating control, but it im mediately assumes a position in proportion to the system requirement. An example of proportional control is a thermostat in a fan discharge duct actuating an automatic valve in the steam supply to a coil to regulate the air temperature leaving the coil. This control would be rimilar to that drown in Tig. I. Throttling range is the total amount of change in the controlled variable required tor the controller to move the controlled device through its complete stroke, from one ex treme to the other. It is often adjustable to meet job re quirements. '- Set point is the value at which the controller is set and represents the desired value of the controlled variable. Control point is the actual value of the controlled variable at which the instrument is controlling. It will vary within the throttling range of the controller according to the demand on the system and other variables. Offset is the difference between the set point and the actual control point under stable conditions. This is sometimes also called drift, deviation, or droop. 5. Proportional phis automatic reset action. Fig. 5, com bines floating action with proportional action to achieve both the stability of proportional control, with a relatively wide throttling range, and the invariable control point of floating control. The system functions the same as proportional action,. the automatic reset serving to shift the control point back to the set point whenever any offset occurs. - jj O0 f3 Fig. 5.... Proportional Plus Automatic Reset Control Showing How Control Point is Returned to Set Point after a Load Change Fig. 3 .... Floating Control Showing Variations in Controlled Variable as Load Changes . 3. Floating action, Fig. 3, is the type, as with two-position action, where the controller can perform only two operations: moving the controlled device usually at a constant rate either towards its open or its closed position. Generally there is a neutral soae between the two positions which allows the con trolled device to stop at any position whenever the controlled variable is within the differential of the controller. When the controlled variable gets outside the differential of the control ler, the controller moves the controlled device in the proper direction. An example of floating control is a firebox draft controller positioning a damper in the breeching of a boiler. Fig. 4------Proportional Control Showing Variations in Controlled Variable as Load Changes 4. Proportional actum. Fig. 4, is the type where the con trolled device is positioned proportionately in response to slight changes in the controlled variable. It does not run through its complete stroke, as is the case with two-position control, nor does it continue to move until the change in the ooatroUed variable resulting from that movement is felt by Reset rate is the number of times per minute the propor tional action is duplicated by the reset action, and usually is expressed as repeats per minute. The reset rate in most con trollers is adjustable and must be carefully matched to the system characteristics to avoid unstable operation. Because automatic reset is necemarily slow-acting, it should be used only when load changes are of reasonably long duration and when the maximum offset resulting from proportional control alone is oustide of acceptable limits. Figs. 4 and 5 show the results of rather abrupt demand changes, which usually result in two or three cycles before stability is restored. More gradual demand change will re sult in a smoother curve. . AUTOMATIC CONTROL SYSTEM COMPONENTS In addition to controllers and controlled devices, many control systems include auxiliary apparatus such as switches and relays of various kinds, clocks or timers, thermometers, gages, pilot lights, and other indicators for observing the operation of the system. Only those more commonly used will be described here. Controllers Automatic controllers have both a measuring element and a controlling element. The measuring element measures changes in the controlled variable and produces a proportional effect on the con trolling element. This effect usually is a change in position, force, or electrical resistance. The controlling element converts the effect produced by the measuring element into an effect suitable for opera Automotic Control 611 tion of the controlled device. (In self-contained controllers the measuring element produces a force which is directly applied to the controlled device. In pneumatic or electronic controllers the controlling element regulates the application of energy such as compressed air or electricity.) Types of Measuring Elements Temperature measuring elements usually consist of (1) a bimetal strip, (2) a rod and tube of dissimilar metals, (3) a sealed bellows, with or without a remote bulb, or (4) an electrical resistance. 1. A bimetal element is composed of two thin strips of disrimilur metals fused together. Because the two metals have different coefficients of thermal expansion, the element bends as the temperature varies and produces a change in position. Depending on the space available and the movement re quired, it may be in the form of a straight strip, U-shaped, ox wound into a spiral. This element finds its most common application in room thermostats, but is also used in insertion ni4 immersion thermostats. 2. A rod-and-tube element consists of a high-expansion metal tube inside of which is a low-expansion rod with one end attached to the rear of the tube. The tube changes length with changes in temperature, the free end of the rod to move. The rod-and-tube element is commonly employed on certain types of insertion and immersion thermostats. 3. A sealed-bellows element is either vapor-filled, gas-filled, or liquid-filled, after being evacuated of air. Changes of tem perature cause changes in pressure or volume of the gas or liquid, resulting in a change in force or a movement. This element is often employed in room thermostats. A remote-bulb element is a sealed bellows or diaphragm to which a bulb or capsule is attached by means of a capillary tube, the entire system being filled with vapor, gas, or liquid. Changes of temperature at the bulb result in changes of pressure or volume which are communicated to* the bellows or diaphragm through the '-capillary tube. The remote-bulb element is useful where the temperature measuring point is remote from the desired thermostat location. It usually is provided with fittings suitable for insertion into a duct or into a pipe or tank. 4. A resistance element is made of wire whose electrical resistance changes with temperature changes. It is used with electronic controllers. It is available in forms suitable for measuring room temperature or for insertion into a duct or into a pipe or tank. Humidity measuring elements are made of (1) hygro scopic organic materials or (2) an electrical resistance. 1. An organic element usually is made of human hair, wood, paper, or animal membrane. Changes in relative humidity cause the element to expand and contract. ' 2. A resistance element, for use - with electronic controllers, frequently consists of a thin coating of hygroscopic salt on an insulating form. The resistance of the salt varies with the relative humidity. ' Pressure measuring elements can be divided into one of two general classes depending upon pressure range. 1. For pressures or vacuums measured in pounds per squsre inch or inches of mercury, the element usually is a bellows, diaphragm, or Bourdon time. One side of the element may be open to atmosphere in which case the element responds to pressures above or below atmospheric. A differential-pressure element has connections to both sides so that it will respond to the difference between two pressures. . 2. For low ranges of pressure or vacuum which are usually measured in inches of water, such as the static pressure in an air duct, the measuring element may be an inverted bell im mersed in oil, a large slack diaphragm, or a large flexible metal bellows. The element usually is of the differential type, and when employed in conjunction with orifices, Pitot tubes, andsimilar-accessories, may be used to measure flow, velocity, or liquid level as well as static pressure. Measuring elements for other purposes, such as flame de tection or for measuring smoke density, specific gravity, CO,, CO, etc., often are necessary for the complete control of a heating, ventilating, or air-conditioning system. Types of Controlling Elements Controlling elements differ because some regulate the ap plication of pneumatic energy while others regulate the ap plication of electrical energy. They also differ according to the type of control action produced. An electric controlling dement is used in several of the the common types of control action. For two-position control it may simply make and break an electrical contact, to start a burner, motor, etc., or to ac tuate a spring-return valve or damper operator. Another type makes one contact while breaking another and is used to control unidirectional valve or damper operators. Either type may be used for timed two-position action by the addition of a small resistance heater. For floating control two contacts are employed, but there is a neutral zone between the two contacts where neither is made. This type is commonly used with reversible valve or damper operators. - For proportional control a contact is moved across a potentiometer to vary the voltage applied to a relay. The . relay controls the operation of a reversible valve or damper operator and is rebalanced as the controlled device is positioned. In another arrangement the controlling element has two con tacts and a neutral zone as described for floating control and is rebalanced by a small solenoid which is energized by a variable voltage feedback from the reversible valve or damper operator which it positions. An electronic controlling element consists of an electronic amplifier and an electric relay or relays. The amplifier re ceives the minute electrical signals from the measuring element and amplifies them sufficiently to actuate the relays. The electronic controlling element may be two-position, floating, or proportional, depending upon the amplifier and relay ar rangement. An electronic-pneumatic controlling element consists of an electronic amplifier and an electropneumatic relay. It may be, two-poeition, or proportional, depending upon the amplifier and relay arrangement. . A pneumatic controlling element is most often of the pro portional action type but may also be used for the other types of control action. It may be classified as nonrelay type and relay type. , A nonrelay type of pneumatic controlling element is the, simplest form employs a restricted air supply and a nozzle or control port. The measuring element varies the opening of the nozzle and the resulting variable pressure is applied to the controlled device. This type is limited to applications requiring small volumes of air. In a relay-type pneumatic controlling element the relay contains both a supply and an exhaust valve usually arranged' so that the exhaust valve must close before the supply valve opens. Both valves are closed except when the control pres-' sure is required to change. The variable force for operating the valves may be supplied directly by the measuring element or it may be supplied by a diaphragm actuated by air pres sure from a very small nozzle and restrictor arrangement, this air pressure being varied by the measuring element. In either case the control pressure, operating on a diaphragm within the relay, produces a force which balances the force produced by the measuring element. Pneumatic controllers may be either direct or reverse acting. A direct-acting controller increases the control air pressure as the controlled variable increases. For .example, a direct- ' acting thermostat increases the air pressure as the temperature increases. ' A reverse-acting controller decreases the control sir pres sure as the controlled variable increases. A reverse-acting 612 CHAPTER 43 1959 Guide thermostat decreases the air pressure as the temperature in creases. the control agent, the outdoor temperature, or other suitable variable. Indicating and Recording Features t. The pneumatic heating-cooling thermostat uses a twopressure air-supply system as described for day-night ther Controllers may be of the indicating or recording type. The nonindicating controller is most common in heat ing, ventilating, ana air-conditioning work, and includes all those in which the measuring element does not provide a visual indication of the value of the controlled variable. If an indication is desired, a separate thermometer, relative humidity indicator, pressure gage, etc., is required. With room thermostats, for example, a separate thermometer often is attached to the cover. An indicating controller has a pointer added to the measur ing element or attached to it by a linkage so that the value of the controlled variable is indicated on a suitable scale. A recording controller is gimilar to an indicating controller except that the indicating pointer is replaced by a recording pen which provides a permanent record on a chart driven by a clock motor. Proportional band is a term used in connection with in dicating and recording controllers and has the same meaning as throttling range. It is usually expressed in percent of the scale or chart range of the controller. mostats. j. A two-stage thermostat is arranged to operate in two successive steps. . fe. A submaster thermostat has its set point raised or lowered over a predetermined range in accordance with variations in output from a master controller. The master controller can be a thermostat, manual switch, pressure controller, or similar device. For example, a master thermostat measuring outdoor air temperature can be used to readjust a submaster ther mostat controlling the water temperature in a heating system. Master-submaster combinations are sometimes designated as single-cascade action. When such action is accomplished by a single thermostat having more than one measuring element, it is known as compensated control. 2. Humidistats are of either the room or insertion type. Submaster humidistats of either type are sometimes used in conjunction with an outdoor master thermostat to reduce the humidity in cold weather and prevent condensation cm win dows. A wet-bulb thermostat is often used for humidity control in conjunction with proper control of the dry-bulb tempera ture. A wick or other means for keeping the bulb wet, and Types of Controllers rapid air motion to asure a true wet-bulb measurement are essential. Controllers are mainly (1) thermostats, (2) humidistats, and (3) pressure types. 3. A pressure or static-pressure controller is made for mount ing directly on a pipe or remotely on a panel or wall. A small pipe or tube may be used for transmitting the pressure signals 1. Many thermostats are of the simple, single-purpose type, but there are msay others for various special purposes. Var ious types are indicated in paragraphs (a) to (fe) which follow. to the instrument. Controlled Devices a. ' The room type is designed for mounting on a wall and responds to room temperature. b. The insertion type is designed for mounting on a duct with its measuring element extending into the duct. Controlled devices may be (1) automatic valves, (2) valve operators, (3) automatic dampers, and (4) damper operators. Other controlled devices include electric heaters, c. The immersion type is designed for mounting on a pipe or tjmlc. It has a fluid-tight connection to allow the measuring and motors on such equipments as fans, pumps, burners, refrigeration compressors, and similar apparatus. element to extend into the fluid. A separable socket or well is often used with immersion thermostats to avoid the need for draining the system when removal of the thermostat is required. Since the separable socket will reduce the response rate of the thermostat, the socket should be no heavier than necessary and should fit snugly around the element. d. The remote-bulb type is designed for applications where the point of temperature measurement is at some distance from the desired thermostat location. It is often used for centralized panel mounting of the controller. The remote-bulb element may be of either the insertion or immersion type. e. The surface type is designed for mounting on and measur ing the temperature of a pipe or similar surface. /. The day-night, or dual room thermostat controls at. a reduced temperature at night. It may be indexed (changed from day to night operation) individually or in groups from a remote point by a manual or time switch. Some electric types have an individual clock and switch built into the thermostat.. g. lie pneumatic day-might thermostat uses a two-pres sure air-eupply system, the two pressures often being 13 and 17 psig or 15 and 20 psig. Changing the pressure at a central point from one value to the other actuates switching devices in the thermostat and indexes them from day to night or vice versa. Supply-air mains often are divided into two or more circuits so that switching can be accomplished in various 1. An automatic valve is designed to control the flow of steam, water, gas, and other fluids and may be considered as a variable orifice which is positioned by an electric or pneu matic operator is response to impulses from the controller. It may be equipped with a throttling plug or v-port of special _ design to provide the desired flow characteristics. . Renewable composition discs are common. They are made of materials best suited to the media handled by the valve, and its temperature and pressure. For high pressures or for superheated steam, metal discs are often employed. Internal ports of valves such as the seat ring, throttling plug or v- port skirt, disc holder, and stem sometimes are made of stain less steel or other hard and corrosion-resistant metals for use in severe service. Automatic valves should be properly selected and sized for the specific applications. See the section on Design Coordination in this chapter for further details. The functions of various types of automatic valves are as follows: . a. A single-seated valve is designed for tight shut-off. Ap propriate disc materials for various pressure ranges and media are used. b. A pilot piston valve utilizes the pressure of the control agent as an aid in operating the valve. It usually is single- seated and is used where large forces are required for valve operation. areas of the building at different times, in accordance with use. For example, a school building may nave separate circuits for classrooms, offices and administrative areas, auditorium, and gymnasium and locker rooms. h. The heating-cooling or summer-winter thermostat can have its action reversed and, if desired, have its set. point c. A double-seated or balanced valve is designed so that the media pressure acting against the valve disc is essentially balanced thereby reducing the force required of the operator. It is widely used where the fluid pressure is too nigh to permit a single-seated valve to close. It cannot be used where tight shut-off is required. changed by the indexing means. It is used to actuate con trolled devices, such as valves or dampers, that regulate a heating source at one time and a cooling source at another time. It is often indexed in groups manually by a switch or automatically by a thermostat measuring the temperature of d. A three-wcsy mixing valve has two inlet connections and one outlet connection and a double-faced disc operating be tween two seats. It is used to mix, as required, two fluids entering the inlet connections and leaving through the com mon outlet. Automatic Control e A three-way diverting valve has one inlet connection and two outlet connections and two separate discs and seats. It is nwd to divert the flow to either of the outlets or to propor tion the flow to both outlets. f x butterfly valve consists of a heavy ring enclosing a disc which rotates on an axis at or near its center, and in principle is similar to a round single-blade damper. The disc usually seats against a ring machined within the body. 2. Valve operators are of three general types: ` . A solenoid consists of a magnetic coil operatic a mov able plunger. It is used for two-position operation. The most common use of a solenoid operated valve is to control the flow of gas, water, air, and refrigerants and generally it is limited to relatively small sizes. . An electric motor operates the valve stem through a gear train and linkage. Electric motor operators are classified, in three distinct types: unidirectional, spring return, or revers ible. Unidirectional, for two-position operation. The valve opens during one-half revolution of the output shaft and closes dur ing the other one-half revolution. Once started, it continues until the half revolution is completed, regardless of subsequent action by the controller. Limit switches built into the operator stop the motor at the end of each stroke. If the controller has been satisfied during this interval the operator will con tinue to the other position. Spring-return, for two-position operation. Electric energy drives the valve to one position and holds it. When the circuit is broken, the spring returns the valve to its normal position. Reversible, for floating and proportional operation. The. motor can run in either direction and can stop in any position. It is sometimes eouipped with a return spring. For propor tional control applications, a potentiometer for rebalancing the control circuit is also driven by the motor. e. A pneumatic operator consists of a spring-opposed flex ible diaphragm or bellows attached to the valve stem in such a way that an increase in air pressure moves the valve stem and at the same time compresses the spring. Springs of vari ous ranges in terms of air pressure can be employed to provide sequence operation of two or more devices by proper selection or adjustment of the springs. Springless pneumatic operators, using two opposed diaphragms or two sides of a angle dia phragm, also are used out generally are limited to special ap plications involving large valves or high pressures. Pneumatic operators are designed primarily for proportional control. Two- position control is accomplished by use of a two-position con troller, or a two-position pneumatic relay to apply either full air pressure or no pressure to the valve operator. Pneumatic valves and valves with spring-return electric operators can be classified ea normally open or normally closed. A normally open valve will assume an open position when all operating force is removed. A normally closed valve will assume a closed position when all' operating force is removed.' ' 3. Automatic dampers are designed to control the flow of air or gases and function like valves in this respect. Steel blades and frames are most common, but other materials are used for special applications such as those involving corrosive fumes. Large dampers often are made in two or more sections for strength and convenience in handling, the sections being interconnected so as to operate as a unit. The damper types commonly used are: a. Single-blade, which is generally restricted to small sizes because of the difficulty of securing proper operation with high-velocity air. ' b. MuUtbladc or louver damper which has two or more blades linked together. It may be arranged for parallel opera tion, in which all blades rotate in the same direction or op posed operation, in which adjacent blades rotate in opposite directions and provide more linear air-flow characteristics than obtained with parallel operation. c. Mixing dampers, composed of two sections interlinked so that one section opens as the other closes. 4. Damper operators of the electric type may be unidirec tional, spring-return, or reversible, similar to electric-motor valve operators. Pneumatic damper operators are similar to pneumatic valve operators except that they usually have a 613 longer stroke ot the stroke is increased by meaua of a mul tiplying lever. Damper operators are mounted on the damper frame and are connected with linkage directly to.a damper blade or are mounted outside the duct and connected to a crank arm attached to a shaft extension of one of the blades. On large dampers two or more operators may be required, aad usually are applied at separate points on the damper. Normally open or normally closed operation is obtained ac cording to the method of mounting the operator and connecting the linkage. Auxiliary Control Equipment In addition to the conventional controllers and controlled devices described, .many control systems require auxiliary devices to perform various functions. Auxiliary controls for electric systems include: 1. Transformers to provide current at the required voltage. 2. Electric relays for control of electric heateis or to start and stop oil burners, refrigeration compressors, fans, pumps, or other apparatus for which the electrical load is too large to be handled directly by the controller. Other uses include time-delay, circuit-interlocking safety applications, and similar functions. 3. Potentiometers for positioning of proportional control devices or for remote set-point adjustment of elec tronic controllers. 4. Manual twitches for manually performing a variety of operations. These may be of two-position or multiple-position type or may be of single or multiple-pole type. 5. Auxiliary switches on valve and damper operators for providing a selected sequence of operations. Auxiliary control equipment for pneumatic systems in cludes: 1. Air compressors and accessories, to provide a source of air at the required pressure. 2. Electropneumatic relays, which are electrically actuated air valves for operating pneumatic equipment in accordance with variations in electrical output. 3. Pneumatic-electric relays, which are actuated by air pressure and make or break an electrical circuit. 4. Pneumatic relays, which are actuated by the pressure from a controller to perform numerous functions. They may be divided into two groups: a. Two-position relays, which permit a controller actuating a proportional device to actuate also one or more two-position devices. They are used in various automatic switching operations. 6. Proportional relays, which are used to reverse the action of a proportional controller, select the higher or lower of two pressures, average two or more pressures, respond to the difference between two pressures, add or subtract pressures, amplify or retard pressure changes, and perform other similar functions. - ' 5. Positioning relays, which are devices for assuring ac curate positioning of a valve or damper operator in response to changes in pressure from a controller. Hey are affected by the position of the operator and the pressure from the controller, and whenever the two are out of balance will change the pressure applied to (he operator until balance is restored. 6. Switching relays, which are pneumatically operated air valves for diverting air from one circuit to another or for opening and closing air circuits. 7. Pneumatic switches, which are manually operated devices for diverting air from one circuit to another or for opening and dosing air circuits. Hey may be of two-position or mul tiple-position type. . 8. Gradual switches, which are proportional devices for manually varying the air pressure in a circuit. Auxiliary control devices common to both electric and pneumatic systems indude: 1. Sequence controllers for operating a number of electric 614 CHAPTER 43 1959 Guide switches in sequence by means of a proportional electric or pneumatic operator. They are commonly used for controlling a number of steps of refrigeration capacity and may be ar ranged to prevent simultaneous starting of compressors and to alternate the sequence to equalise wear. They may also be used for sequence operation of electric heaters and other equipment in response to the demands of a proportional con troller. 2. Clocks or timers for turning apparatus on and off at pre determined times, for switching control systems from day to night operation, and for other time sequence functions. PART II--DESIGN COORDINATION A heating or cooling system is designed to meet maximum conditions but functions at partial capacity much of the lame. The ability to properly control the system at all timas is one of the most important factors having to do with the design of the system and for this reason the proper use and application of controls should be considered at the time the heating or. cooling system is being designed. Wherever possible the system should be designed to facilitate control operation. This section includes factors which should be considered in the design of a new heating or cooling system, . or the modernisation of an existing one, to enable the con trol system to produce the best posable results. The design of the system and its controls should take into consideration the nature and type of the building in which it is to be used and the results it is desired to accomplish. Quality of the control equipment should be consistent with the accuracy of control required. Where results more pre cise than those for normal comfort applications are re quired, such as in certain manufacturing areas, constant temperature rooms, etc., both the air-conditioning system and the control system should be given special consideration so that the required results can be.produced. Controls can be made to produce almost any degree of accuracy required, but it is useless to provide such controls unless the air . conditioning system is capable of properly responding to the demands of the controllers. For example, it is virtually impossible to maintain dose control of temperature and humidity by starting and stopping a refrigeration com pressor or opening and dosing a refrigerant valve. It is necessary instead to employ refrigeration equipment that will permit proportional control by one of the methods discussed in Chapter 38, or to use a chilled-water system with a cooling coil or air washer that will permit proportional control. Neither is it good practice or economical to select equipment capable of producing far more precise control than the application requires, or to complicate the system . to obtain special sequences or cycles of operation when not necessary. It is well to remember that the system must be adjusted and maintained in operation for many years, . and that the amplest system which will produce the neces sary results is usually the best. . SIZE OF CONTROLLED AREA No individually controlled area should be excesively large because the difficulties of obtaining good distribution and of finding a representative location for the space con trols become greater as the area increases. Each individually' controlled area must have similar load characteristics throughout and otherwise should- conform to the recom mendations given in the section on Zone Control. For uni form conditions throughout the area equitable distribution must be provided by competent engineering design, careful siring of equipment, and proper balancing of the system. The control can measure conditions only at the point where it is located, and it cannot compensate for variable conditions throughout the area caused by improper distribution or in adequate design. Areas or rooms having dissimilar load characteristics, or having different conditions to be main tained, should be individually controlled. The smaller the controlled area the better will be the control obtained and the more nearly will the system approach the optimum in performance and flexibility. Even when individual room control is employed it often is well to consider some form of overall zone control of the whole system in accordance with the major factor influencing system load. Thus the water temperature in a hot water heating system, the steam temperature or pressure in a steam heating system, or the delivered air temperature in a central fan system may be varied inversely as the out door temperature varies. This obtains a fair share of the necessary control on the system as a whole, relieves the individual space controls of a part- of their burden, and makes more accurate space control possible. Furthermore, modifying the basic rate of heating or cooling input to the system in accordance with system load reduces losses in the distribution system. The cost of the additional controls is often justified by the reduction in operating costs. . Where such overall system controls are employed, accurate zoning, while desirable, is not necessary. The system must always be able to satisfy the area or room having the greatest demand. The individual controls take care of the variations in demand within the area served by the system. The more accurately the system is zoned the larger will be the share of the control accomplished by the overall system controls, the smaller will be the system distribution losses, and the more accurately will the individual space' controls be able to maintain the space conditions. ' EQUIPMENT SRECTION AND LAYOUT Heating and cooling coils should be carefully selected to avoid oversizing. A coil that is too large is not only more difficult to control but will increase air temperature strati fication. When temperature measuring elements are to be ' placed between coils, ample space between the coils must be provided. The measuring element should be located as near as possible to the coil it is controlling. For example,' an idle water coil interposed between a thermostat and the coil it is controlling introduces anmigh thermal inertia to make it difficult to produce stable control. The elimination of stratification in an air-handling system is essentia] not only in producing good control but in ob taining equitable distribution of heating or cooling. Outdoor-. air and return-air dampers should be arranged in such a way as to help blend the outdoor air nH return air.. Face dampers should be placed far enough from coils to allow for equalization of air flow over the coil surface. The con troller for face and bypass dampers must be located far enough downstream so that the air has become thoroughly ' mixed before reaching the controller. Other sources of strati fication are coils which heat or cool unevenly and coils ar-. ranged in parallel and controlled in sequence. Whenever' stratification cannot be eliminated by proper design or ar rangement of equipment, special baffles, miring chambers,1 or other mechanical'devices should be used for this purpose. If stratification still exists at a point where the measuring. element of a thermostat is to be located,.the use of a long averaging element, or one made up of a number of small elements, may make a suitable temperature measurement possible. This does not solve the other problems relating Automatic Control 615 to stratification which can cause discomfort or, in extreme cases, freezing of equipment. Good air distribution and properly spaced diffusers and grilles will greatly assist in maintaining even temperatures throughout an area. A space temperature controller cannot prevent drafts. This can be accomplished only by proper at tention to such factors as balancing the system, by intro ducing air in the correct manner, and by providing a suitable low-limit control on the delivered-air temperature. A system that employs constant air volume with variable air temperature results in more uniform distribution than one which requires variations in air volume to achieve tem perature control. Varying the volume of air affects both ventilation and distribution, two factors which usually have little relation to thermal requirements. Return-air grilles usually can and should be located so as to aid both the distribution and control of the system. A further aid to both distribution and control is the pro virion of adequate facilities for exhausting air from the building. The larger the percentage of outdoor air introduced the more important becomes the provision for adequate exhaust. To prevent drafts due to infiltration, it is quite common to provide for positive exhaust of less air than is brought in. On systems where the quantity of outdoor air is large but constant, this may be accomplished by use of a properly sized exhaust fan. Systems having large in ternal heat gains, or large solar gains, may use a variable amount of outdoor air up to 100 percent when cooling is required during cool weather. In such cases the outdoor-' air quantity may be controlled from space conditions and the quantity of exhaust air may be controlled by a staticpressure controller set to maintain the space under a slight positive pressure. LOCATION OF SPACE CONTROLLERS Space controllers such as room thermostats must be placed " where they will measure the variables they are to control and where the condition is representative of the whole area served by the controller. If the return-air duct is used to represent space conditions, the controller should be located as near the space as possible to eliminate the effect of any heat gain or loss in the duct. Room thermostats should usually be placed in occupied areas on inside walls or columns. They should never be placed in spaces such as corridors, lobbies, and foyers unless they are used for the control of these areas only. In a typical home which is not zoned a satisfactory loca tion for a room thermostat mn usually be found on an inside wall of the living room or dining room. It should always be located toward the center of a relatively open room situated on the coolest rather than the warmest side of the building. It should not be mounted on an outside wall or other cold surface where it is exposed to cold drafts from an outride door. Neither should it be mounted where it will be affected by direct rays of the sun; by heat from a nearby warm sur face such as a chimney, pipes or ducts in the wall, or radiators, or by direct air currents from a register. The loca tion should provide ample air circulation unimpeded by furniture ox other obstructions, and should afford protection from mechanical injury. CONTROL OF ROW The successful operation of practically any air-condition ing system is dependent on the proper control of flow in one form or another. The flow being controlled may be steam, water, air, or some combination thereof. In each case a controlled device is used to regulate the flow atthe command of a controller. The proper design and sizing of these controlled devices, valves for steam or water, and dampers for air, are essential to obtain the desired results from the air-conditioning system. The performance of a valve or damper is expressed by the control industry in terms of its flow characteristics as it operates through its stroke, based on a constant pressure drop. Three common characteristics are shown in Fig. 6 and may be defined as follows: Quick Opening: Maximum flow is approached rapidly as the device begins to open. Linear: Opening and flow are related in direct proportion. Equal Percentage: Bach equal increment of opening in creases the flow by an equal percentage over the previous value. , Fig. 6.... Typical Flow Characteristics Since the pressure drop across a valve or damper seldom remains constant as its opening changes, actual performance usually deviates from the published characteristic curve. The magnitude of the deviation is determined by the over all system design. For example, in a system arranged so that control valves or dampers can shut off all flow, the pressure drop across a controlled device increases from a minimum at design conditions to the total system pressure drop at no flow. Fig. 7 shows the extent of the resulting deviations for a valve or damper designed with a Hruar characteristic, when the selection is based on various per centages of the total system pressure drop. In order to approximate the designed characteristic of the valve or damper, the design pressure drop should be a reasonably large percentage of the total system pressure drop or the system should be designed and controlled in such a manner that this pressure drop remains relatively constant. Higher pressure drops for controlled devices are obtained by using smaller sizes in conjunction with a possible in crease in size of other equipment in the system. Since 616 CHAPTER 43 1959 Guide fig. 7.... Typical Performance Curves for Linear Devices Selected at Various Percentages of Totol System Pressure Drop sizing techniques are different for steam, water, and air, wh is covered separately. THE CONTROL OF STEAM FLOW The size of an automatic steam valve is based on the re quired capacity at maximum load, under the conditions which will exist at that time. Equation 52, Chapter 4, for massflow through an orifice or nozzle can be rewritten as io - caVp, - p, . ( where . w " the flow of steam in pounds per hour. A TM the area of the port opening in square inches. Pi =* the steam supply pressure, pounds per square inch, absolute. ' Ft the downstream pressure, pounds per square inch, absolute. ' C * a constant for a given steam supply pressure and a given valve.body. Valves for two-position operation usually are selected of a size adequate to supply the required maximum capacity with a reasonably low pressure drop (Pi -- Pi). It is necessary only to be sure that the valve will close against the system pressure and will have ample capacity when fully open. . Proportional valves for steam service must be carefully sized if stable control is to be achieved. Since, in general, the tendency is to oversize such valves it should be remembered that no controller can produce its best results if handicapped by a valve which is too large. The function of the valve is to vary the value of area A in Equation 1 and it is desirable that tire flow vary in proportion to the value of A. The cor rect maiimnm required capacity must first be determined. There should be no factor of safety in this determination, and it should be based on actual heating requirements rather than on the condensing capacity of the coil, since the coil may be larger than necessary. It is also necessary to base the valve size on-the actual supply pressure Pi which will exist at the valve, since this supply pressure affects both the density of the steam and the pressure drop which will'be selected. Selecting the proper pressure drop (Pi -- Pi) across the valve when it is wide open and is supplying the maximum 8team requirement is the most important consideration in determining the valve size. For purposes of discussion it will be assumed that Pi U constant and that the valve is supply ing steam to a heating coil which has air entering at a constant temperature and velocity. Any pressure drop between the valve and the coil will be neglected so that Pi represents the pressure in the coil. The condensing capacity of the coil varies with changing values of P*. When the valve is fully open, P* assumes a value such that the capacity of the valve and the condensing rate of the coil are in balance. If this value of Pi is relatively large, then, as the valve is partially closed, Ps will decrease until the capacity of the valve and the condensing rate of the coil are again in balance. Reducing the value of A in Equation 1 results in an increase in' the value of \/Pi -- P* and partially offsets the effect of closing the valve. This effect is greatest when P* is nearly equal to Pi and diminishes as P* decreases. The minimum value which P* can assume is established by the return line pressure (or vacuum) of the system. However, P* may reach a value which results in tile critical velocity through the valve before it has been reduced to its minimum value. If so, any reduction of Pi beyond this value has no further effect on the valve capacity. The critical velocity exists when Pt is approximately 58 percent of Pi. The unde sirable effect caused by variations in P, can be eliminated by selecting a valve size such that Pf is at or near its minimum value, or the value corresponding to the critical velocity, whichever is higher, when the valve is wide open. On low-pressure steam applications it is good practice to base the valve size on a pressure differential equal to 75 or 100 percent of the gage supply pressure. When the supply pressure is high enough so P* at the critical velocity (58 percent of Pj) is above atmospheric pressure, the valve size can be based on a pressure differential of 42 percent of Pi absolute. All valves of the same size do uot have the same capacity for a given pressure differential. Having established the supply pressure and the pressure differential, the valve manufacturer's tables or charts should be consulted in selecting the proper size of valve for the required capacity. It is important that the supply pressure to an automatic steam valve be constant because it is difficult for a thermostat to produce stable results if the pressure is constantly changing. This situation arises, for example, when a steam boiler is operated by a two-position pressure controller. A pressurereducing valve, which will supply a constant pressure to the steam mains while permitting the boiler pressure to fluctuate , between the limits of the pressure controller, is recommended. T siting this, the differential of the pressure controller should be set as narrow as is consistent with efficient boiler and burner operation. On vacuum return systems the vacuum pump also should operate on a narrow differential. The use of two automatic control valves in parallel will often provide more stable control than a single larger valve, especially on large coils or steam-to-water heat exchangers. The valves should be sized so that one valve handles about one-third of the total capacity and the other about twothirds. They are controlled in sequence so that the small valve operates during periods of light load and the large valve begins to open only after the load exceeds the capacity of the gmft.ll valve. Automatic Control 617 The steam piping from the valve to the coil inlet, and from the outlet to the trap should be the full size of the coil tapping or size specified.by the manufacturer of the coil and should conform to good standard practice as illustrated in Chapter 26.It is very important that condensate be promptly drained from the coil. When the coil is at reduced pressure, as it will be much of the time, there will not be sufficient difference in pressure between the coil and the return line to obtain any lifting of the condensate. THE CONTROL OF WATER HOW The capacity of a proportional valve for water service is not influenced by the supply water pressure but only by the pressure differential. This is so because water is incompressible and because the inlet pressure is not an important factor in the thermal capacity of a water system. If a certain water circuit has a totol resistance of 30 psi at maximum flow, of which 1 psi is through the valve, the resistance of the rest of the circuit is 29 psi. As the valve closes and flow is stopped the resistance across the valve be comes the entire 30 psi. Thus the pressure drop across the valve increased by a ratio of 30:1 as the valve travelled from full open to full closed position. This increase in pressure drop as the valve is closed offsets partially the effect of closing the valve. ' It is obviously impracticable to design a water system such that there will be no increase in pressure drop across the valve as it closes. However, it is important to design the system, including the valve, in such a manner that the ratio of this increase in pressure drop as the valve closes is kept as low as possible. Thus, if the design pressure drop across the valve is 5 psi instead of 1 psi,"the ratio of increase is only 6:1 instead of 30:1 and the performance of the valve will be improved accordingly. This discussion assumes a circuit in which the entire flow is controlled by a single valve. The same reasoning will apply to the more' complicated systems involving a multiplicity of parallel circuits, each having a valve. In general it can be said that the pressure drop across a water valve at full flow should be a reasonable percentage of the resistance of the circuit in which the valve controls the flow. Due consideration should be given to any resultant increase in pumping head and operating costs. - Consideration must also be given to the fact that the Btu release from the hot water .eoil does not vary in direct proportion to changes in flow, i.e., as flow is reduced the water temperature drop through the eoil increases so that there is very little change in the total heat given off. Con versely, this is true for cold water coils. Considerable im provement^ in control valve operation is obtained where systems are designed for large temperature drop and valves are selected at minimum practical size. Special designs of throttling plugs in valves may further improve control. Water circuits involving variable flow are subject to variable pressures in accordance with the pressure vs. flow characteristic of the pump. On such circuits it is desirable to provide some means of system pressure control. A by pass from supply to return is often used to accomplish this. The bypass connection either has a spring-loaded relief valve, subject to the system pressure difference, or an auto matic control valve operated by a differential-pressure con troller. . Another very important consideration when using hot water as the heating medium, is that the heat output of a coil is not linearly related to flow. As the flow is reduced. fig. 8 .... Heat Emission vs. Flow Characteristics of Typical Hot Water Heating Coil a greater amount of heat is transferred- from each gallon of water and this tends to counteract the reduction in flow. Fig. 8 shows the heat emission versus flow characteristics for a typical coil with 220 F entering water and a 20 deg design temperature drop and shows how the temperature drop increases as the flow is reduced. To improve the coil characteristics for hot water, it is passible to design for higher water temperature drops. Selecting a temperature drop of 60 deg would require a slightly larger coil but would improve control performance and substantially lower the water requirements. This re duction in gpm also results in smaller pipe sizes,, smaller control valves, and reduced pumping costs. A properly sized control valve with equal percentage characteristics should be used to control the flow of hot water to coils for modulating service. CONTROL OF AIR FLOW It is common practice to size a damper to fit the duct into which it is installed. This usually results in a very low design pressure drop across the damper. It also keeps the fan horsepower requirements as low as posable. In some cases this practice results in very poor control performance. This is particularly true of dampers used to control the entire flow into a large duct, such as a static pressure damper. For a constant pressure drop, the flow characteristic of a damper varies with the number of blades, the manner in which the' blades rotate with respect to each other, and the length to width ratio of blades.1 Dampers commonly are of the single-blade or multiblade type. The latter may have blades with either parallel or opposed operation. When the application is such that the pressure drop across the damper increases substantially as it closes, it is preferable to use opposed blade dampers. As explained in a pre ceding section. Control of Flow, the changing pressure will cause a deviation from the design- flow characteristic. This will change the performance from nearly equal per centage to nearly linear as shown in Fig. 9. Even though Fig. 9 indicates good performance from an opposed blade damper under the conditions tested, it does not eliminate the need for using smaller dampers with higher design pressure drops in some applications. An ex treme example is a static-pressure damper in a high-velocity system. Such a damper should not be placed in the low- X 618 CHAPTER 43 1959 Guide fig. 9.... Effect of Pressure Drop Selection on OpposedBlade Damper Performance velocity coil section where it would have a design pressure drop of less than 0.1 in. water, if it is expected to control with 2 to 3 in. pressure drop during periods of low flow. It should be placed in a high-velocity section where the Hftgjgn pressure drop will be 0.5 in. water or more, careful consideration being given to avoid excessive turbulence on either entering or leaving side of the damper. ZONE CONTROL Zone control for any heating, ventilating, or air-con ditioning system is employed where it is desired to control, by one set of controls, the heating or cooling, effect in a number of rooms or areas, having similar orientation or occupancy. For tone control to be successful the require ments must be approximately consistent throughout the extent of the zone. Whether zoning a building for heating or cooling, tiie following factors should be considered in de termining the number and arrangement of the zones: 1. Exposure. Solar effect, prevailing winds, and the shelter afforded by surrounding structures affect the heat gain or loss. 2. Occupancy. Indoor temperature requirements for the various activities carried on in different portions of the building and the hours of occupancy of the various spaces impose definite control problems. 3. Building Structure. The physical characteristics of the building will influence the subdivisions of the system into zones since satisfactory temperature conditions throughout a single zone of given extent may not be obtainable equally in buildings of HiHuimilar types of construction. Other factors are the height of the building and its horizontal extent and form. 4. Floors. Even though several floors have the same wall exposure, it is advisable to have separate zones on the lowest ana highest floors.due to variations of basement or ground floor requirements and the effect of roof exposure. It is also desirable to have a separate zone or zones for the intermediate floors. The initial investment will often influence the decision as to the final number of zones to be employed. In larger buildings accepted practice is to have at least one zone for each exposure. Each exposure may require subdivision vertically into two or more zones for the higher structures. Also, the presence of two or more wings having the sama general exposure may suggest the desirability of more re strictive zoning. When the street floor or any other portion of the building is used for public occupancy or activities which differ from those carried on in the remainder of the building, it is desirable to provide separate thermostats and controls for each individual area. Zone controls alone may not provide satisfactory tem perature conditions in all rooms or areas within the zone because occupancy, lighting load, space arrangements, and similar factors cannot always be predicted with accuracy. A combination of zone controls with individual room control in critical areas may be necessary to achieve complete satis faction. INDIVIDUAL ROOM CONTROL The ideal temperature control system for any building is one that promotes mnint^nanra of the desired tempera ture in every room at all times regardless of location and occupancy. Individual room temperature control is desirable for securing proper thermal environment in schools, hos pitals, and offices. . ' Control of the temperature in each room, or possibly of adjacent roams having the same orientation (as in an apart ment), overcomes many of the problems encountered when attempting to regulate the temperature of a building as a whole or of large areas or zones. Each individual thermostat controls the heat input to its particular space regardless of occupancy or exposure to sun and wind. The advantage of individual room control is in fuel economy and comfort' for the occupants. Each room should have & thermostat that controls valves or dampers on all the controllable sources of heating and cooling. One such uncontrolled source may prevent proper operation of the control system. ' PART 111--CONTROL APPLICATIONS Applications of controls to systems or apparatus of a general nature will be found in this section. Applications pertaining to specific systems or apparatus will be found in the chapters covering these subjects. The application of con trols may conveniently be considered for the three divisions of a system indicated in Fig. 10: (1) primary source ap paratus, (2) distribution system, and (3) terminal equip ment. PRIMARY SOURCE APPARATUS cr TERMINAL EQUIPMENT DISTRIBUTION SYSTEM fig. 10____Three General Divisions of Control Applications PRIMARY SOURCE APPARATUS The control of primary source apparatus is described in the following chapters: Chapter 18, Warm Air Heating Systems, Chapter 34, Automatic Fuel-burning Equipment, Chapter 39, The Heat Pump, and Chapter 38, Refrigera tion. The second and third divisions are considered in this section. DISTRIBUTION SYSTEMS The control of distribution systems is discussed sepa rately for central fan systems, hot water systems, zoned steam systems, and zoned hot water systems, due to the dif ference in these systems. Automatic Control 619 RETURN AIR ] .--1_ MIXED AIR || |*-OW LIMIT h-1 | CONTROLLER routdoor' AIR i! ------------------------------- ---------------------------- l --(SMiANUAL SWITCH fig. 11....Manual Adjustment of Outdoor-Air Quantity - With Low-Limit Control of Mixture Temperature CENTRAL FAN SYSTEMS Refer to Chapter 19 for additional material on control for a typical central fan system. Since there are numerous control combinations that can be employed with central fan systems, the following sections will deal with only a few of the typical combina tions for controlling outdoor- and return-air dampers, pre heat coils, heating coils, cooling coils, and humidity control. The complete control system is obtained by combining the selected method for each item into an integrated set of controls. Proper consideration must be given to the inter relation of the several parts and the sequence of operation, etc. Outdoor-Air Damper Control Outdoor air for ventilation is usually controlled by a damper arrangement providing a homogeneous mixture of outdoor air and recirculated air. Outdoor air-to meet mini mum ventilation requirements should be available whenever the fan is running and is usually provided in one of the fol lowing ways: a. By a minimum outdoor-air damper which is fuDy .open . when the fan is started. A maximum outdoor-air damper may also be provided if additional outdoor air for natural - cooling is desired. - b. By an outdoor-air damper which opens to a minimum position when .the fan is started. Additional outdoor air is provided by further opening of the damper under automatic control. Recirculated-air and exhaust-air dampers are synchronized to operate with the outdoor-air dampers. Mechanical inter connections are preferable bu^separate operators on each of the dampers can be used when mechanm-ai interconnec tions are impractical. In most arrangements provisions are made to prevent admission of more than the minimum out door air required for ventilation both during heating opera tion and when the outdoor-air temperature is too high to provide some natural cooling. Provisions should also be made to close the outdoor-air and exhaust-air dampers and open the return-air damper whenever the fan is stopped. Fig. 11 shows a system having manual adjustment for maximum outdoor air and having an optional, but very desirable, mixed-air controller. This controller overrides the manual switch whenever the mixed-air temperature drops below its set point. This provides for a minimum mixedair temperature for safety of downstream equipment. When ever the fan motor is stopped the outdoor-air and exhaustair dampers close while the return-air damper opens. Fig. 12 shows an all-season ventilation control system with a fixed minimum quantity of outdoor air and auto matic control of maximum outdoor- and return-air dampers. This arrangement is sometimes referred to as an economizer control of outdoor air. With outdoor-air temperatures be low the set point of the summer controller, the mixed-air controller positions the outdoor- and return-air dampers. When outdoor-air temperature rises to the set point of the outdoor high-limit controller, usually about 70 F, the maximum outdoor-air damper is closed and the return-air damper opened. The minimum quantity of outdoor air is 'assured by the separate minimum outdoor-air damper. Both outdoor-air dampers are closed and the return-air damper opened whenever the fan motor is stopped. By adding a thermostat in the conditioned space or in the re turn-air duct the opening of the maximum outdoor-air damper can be limited to only the desired minimum quan tity of outdoor air until the space heating requirements are satisfied. This feature is desirable for quick warm-up during winter heating. Preheater Coil Control The function of a preheater is to temper the outdoor air to prevent the possibility of freezing beyond the coil. Care must be taken to avoid freezing in the coil itself. The proper selection, installation, and sizing of steam traps are very important to assure rapid elimination of condensate to pre vent freezing. Other important considerations are vacuum breakers to insure condensate removal, provisions for rapid air elimination from coil, and the use of vertical rather than horizontal tubes wherever possible. Fig. 13 shows a simple application of an outdoor ther mostat usually set for 35 F controlling the preheat coil valve. Careful sizing of the coil is very important with this type of control. The temperature rise through the coil should be limited to a maximum of 30 deg when the entering air is 35 F. A higher temperature rise will very likely cause overheating of the space. If more than a 30 deg temperature rise is needed then multiple coils should be used and their control valves operated in sequence at selected outdoor temperatures. Fig. 14 offers a method of control which reduces the OA. THERMOSTAT Minimum Outdoor Air Phis Additional Outdoor Air When Practicable . 620 CHAPTER 43 DISCHARGE.LOW LIMIT THERMOSTAT fMnonat uwtkM-A 1959 Guide Automatic Control 621 Damper Control From Mixed Air overheating problem outlined for Fig. 13. Here a mixed- air thermostat operates an outdoor-dr bypass damper in conjunction with the exhaust- and return-air dampers. The use of bypassed outdoor air makes it. possible to control the mixed-air temperature without endangering the pre heat coil. A minimum quantity of outdoor air is assured by use of a two-position face damper on the coil. . Steam-distributing type' coils can be controlled by a proportional-type thermostat set for 55 F or higher and located downstream from the coil to operate a valve in the steam supply line. Where a temperature rise of more than 30 deg is required, two or more coils in series should be used, each having a separate valve. This arrangement is shown in Fig. 15. The valves should be arranged to operate in sequence, with the valve on the upstream coil opening first. Hot water preheat coils should be controlled by face and bypass dampers operated by a thermostat downstream from the coil, with continuous water circulation when the outdoor air is below freezing. A pressure switch to stop the fan in 'case of pump failure is often employed. Further freeze protection can be accomplished by a' thermostat in the coil outlet arranged to stop the fan if the water temperature drops to 35 F. In all applications where face and bypass dampers are used, precautionary measures must be taken to prevent stratification of the mixture beyond the coil. One method is to locate the bypam damper above the face damper so that the cooler bypassed air will tend to drop while the wanner air through the face damper tends to rise thereby mixing the air by gravity. Heating Coil Control Heating coils when used for tempering air. for ventila tion can be controlled by a proportional type of insertion Discharge Air Using Valve - thermostat, preferably located in the fan discharge where the air is usually least stratified. This thermostat operates the heating coil valve or valves, or face and bypass dampers, to maintain a constant discharge air temperature. When face and bypass dampers are used it is good practice to have a valve on the coil which closes as the face damper closes to prevent overheating due to radiation from the coil, damper leakage, or escape of heat from the coil. Fig. 16 shows a typical control arrangement for a heat ing coil when the fan system is used for heating as well as for ventilation. Here a room or a return-air thermostat controls the heating coil valve until the space temperature is satisfied. A discharge duct thermostat then assumes con trol of the valve to maintain the desired minimum air dis charge temperature. With this system no portion of the air entering the coil should be les3 than 32 F. Fig. 17 shows an arrangement using face and bypass dampers on the heating coil and two-position control of the valve. It should be noted that .without a low-limit controller the air entering temperature must be the desired minimum discharge air temperature. Fig. 18 offers a typical water coil control application. The room or the return-air duct thermostat operates the three-way mixing valve until the space temperature is satisfied. The discharge duct thermostat then takes over the valve control to maintain the desired minimum air discharge temperature. Cooling and Dehumidification Coil Controls Dehumidification by condensation is so closely related to sensible cooling that it is convenient to discuss them together. Three typical applications of controls are discussed. - Direct-Expansion Systems. A thermostat measuring the space temperature may be used to open and close a solenoid - refrigerant valve on the coil inlet; control the starting' Fig. 18....Control of Hot Water Coil From Space and Discharge Air Using Mixing Valve. Rg. 20.... Control of Chilled Water Coil From Space Temperature Using Return Bypass Damper and Valve and stopping of one or more refrigerating compressors, or otherwise control the compressor capacity; position face and bypass dampers, or a return-air bypass damper, in com bination with the opening and closing of the refrigerant coil valve or the starting and stopping of the compressor; or control a back pressure regulating valve with proportional action. The positive opening and closing of the refrigerant valve or the starting and stopping of the' refrigeration compressor will result in wide variations in discharge tem perature and dehumidification. When such variations are objectionable, it is desirable to employ proportional damper controls or proportional control of refrigerant flow in con junction with refrigeration equipment capacity controls as discussed in Chapter 38. Chilled-Water and Brine Coils. A thermostat m^agimng the space temperature may be used to control a valve on the inlet or outlet of the cooling coil; control a three-way mix ing valve; position face and bypass dampers at the coil; or position a return-air bypass damper. An apparatus dew point thermostat may also be used to control 'the cooling coil valve. When cooling capacity is controlled only by a dry-bulb thermostat the amount of will vary with the sensible cooling rfflmanH When independent dehumidification is required it is necessary to employ some form of reheat. Fig. 19 shows a simple arrangement where chilled water is supplied to the coil at a constant temperature and the water volume through the coil is varied. The space or return-air thermostat modulates the three-way valve to increase or decrease the volume of water through the coil. Although this arrangement provides constant flow through the chiller, it should be noted that throttling of chilled water to the coil causes higher coil temperatures with light sensible cooling loads which may result in unsatisfactory humidity conditions. Fig. 20 shows a control system using-two-position control of a cold water coil valve and modulating control of a return-air bypass damper. Here the cooled air through the coil.is mixed with bypassed return air to satisfy the space thermostat demands. When the return-air bypass damper is fully opened the water valve can be closed. It is often desirable to omit the valve control and instead maintain a constant flow of chilled water through the coil. This provides some dehumidification with light sensible cooling loads. Air Washers. Since the air leaving an efficient washer is practically saturated, the temperature of the spray water will determine the dew-point temperature of the air leav ing the washer. With this condition it is possible to maintain very accurate dew-point temperatures and consequently accurate relative humidities under a given ratio of sensible-to-latent heat gain in the conditioned space, provided the space dry-bulb temperature is accurately controlled. In general, the water pump operates continuously and a thermo stat measuring the dew-point temperature is used to position a three-way valve to mir refrigerated water with bypassed washer water. To compensate for variations in latent load, a humidistat measuring the space relative humidity may be employed as a master controller to readjust the set point of a dew-point submaster controller. Humidity Controls Fig. 21 shows a simple method of humidity control em ploying a room or a retum-air duct hrnnidirt^t to control a valve supplying steam to an evaporator pan type hu midifier. Additional control provides for closing the valve Fig. 15.... Proportional Control of Two Preheat Coils in Sequence . Fig. 17.... Control of Heating Coil From Space Temperature Using Valve and Face and Bypass Dampers Fig. 19.... Control of Chilled, Water Coil From Space Temperature Using Mixing Valve 622 CHAPTER 43 1959 Guide when the fan is stopped. This prevents evaporation of water which might later condense in the ductwork and cause damage. Since untreated city water is evaporated there are none of the objectionable odors usually caused by chemi cally treated boiler water. Such odors often are noticeable with steam jet humidifiers. Control of steam jet humidifiers is the same as for pan humidifiers. Control of atomizing water spray humidifiers also is the same as for pan humidifiers except that two-position valve action must be employed. This action is necessary in order to obtain efficient atomization. fig. 22 shows an example of winter dew-point control of an air washer humidifier. A space or return-air huxnidistat readjusts the set point of the dew-point controller to com pensate for latent load changes. If the latent load of the space is constant then the bumidistat can be omitted in which case the dew-point controller would control at a constant set point. The dew-point controller increases the temperature first by doting the maximum outdoor-air damper and then by gradually opening the water heater valve. Static-Pressure Control Since fans are selected to produce the desired results for a certain system characteristic, any change in the system characteristic will change the output of the fan. Such changes occur, for example, on single-duct systems in which the volume of air delivered is varied and in double-duct systems where quantities of air are shifted from one duct to the other to obtain final space control. System character istics may also change when the relative quantities of out door air and recirculated air are varied, when exhaust fans are run intermittently, and for other reasons. Such changes result in a changing static pressure in the system, a changing noise level, and changing velocities at air out lets which upset the air-flow patterns. Static-pressure control of some form is usually required on such systems, and is accomplished by a static-pressure controller measuring the pressure at a selected point in the system with respect to an atmospheric reference point or some other point intide the building. It can be used to ac tuate a damper operator on fan inlet vanes, on a multi blade damper on the suction or discharge tide of the fan, or on a damper in a bypass connection between the fan discharge and the fan suction. fig. 23 shows a simple method of static-pressure con trol. Here a differential-pressure controller measures the static pressure in the supply duct in relation to some reference space such as outdoors. With increase in duct static pressure due to throttling of space volume control dampers the controller throttles the static-pressure damper proportionately. For controlling system static pressure, louver dampers may be installed on either the suction or discharge tide of the fan or fan inlet vanes .may be em ployed. To control static pressures in various sections of a distribution system, louver dampers are installed in the inlets to the various sections, with separate staticpressure controllers for each section. Measuring tubes must be located within the system or section at a point where constant pressures are most desirable. Control of a Typical Central Fan System Fig. 24 shows an example of control arrangement using some of the system components previously described and referred to in Part II of this chapter under Design Co ordination. Hie controls can be pneumatic, electric, or electronic. When the fan is started relay B-l, actuated by the fan- motor starter, opens outdoor-air damper D-l, places hu- midistat H in service, and allows insertion thermostat T-l to operate preheat coil valve V-l, maximum outdoor-air damper D-S, return-air damper DS,' and exhaust- damper D~4- When the fan stops, B-l is de-energized thereby closing dampers D-l, D-t, and D-4 while opening DS. Humidifier valve V-4 is dosed and preheat valve V-l is opened. The sequence of operation described will in general also apply to high-presure fan systems except that it is con sidered desirable to open the outdoor-air damper before starting the fan. With this arrangement, a manual- switch operates damper D-l- An auxiliary switch mounted on the damper starts the fan when the damper is fully open. It also stops the fan when the damper starts to close. Insertion thermostat T-l maintjuns a temperature of 55 F at the preheat coil discharge by operating preheat coil valve V-l. This serves as a low limit for the fan discharge temperature during heating operation. When V-l is closed, thermostat T-l then gradually opens maximum outdoor-air damper D-S and closes return-air damper D-S proportionately. At 55 F outdoor temperature'D-5 is wide open and D-S is closed. Exhaust-air damper D-4 opens and closes in synchronization with D-S. At about 70 F out doors, when the outdoor air is no longer useful for natural cooling, T-S closes D-S and D-4 and opens DS. . Reheater coil valve VS is controlled by submaster thermostat TS in the fan discharge. This thermostat is auto matically readjusted over an appropriate range of tem perature by thermostat T-4 so that the discharge tem- SPACE HUMKXTY ____ acorn AIR CONTROLLER [J 'PROPORTIONING) J j i 1 SUBMASTCR OEW*-----tH--. POINT CONTROLLER LJ | 1 (PROPORTIONING) > | |---- IAAX. QA.; ^OAM&tS iI k3 i5 j-- MIN QA. j1 1 1 '\ 'Ss` . / A ! 4- (-' l____ --en^:}*re*"wu* *nT'v ----j WATER tCATtft Rg. 22.... Control of Air Washer Humidifier With Submaster Dew-Point Controller Variable Volume System Automatic Control 623 Rg. 24.... Control Diagram for a Typical Central Fan Air-conditioning System perature matches the space requirements. When the space temperature tends to rise above a predetermined value, TS has been readjusted downward far enough to keep reheat valve V-5 closed. T-4 then controls cooling coil valve V-S directly to maintain the desired space temperature. Humidistat H operates humidifier valve V-4 to maintain the desired humidity in the conditioned space. It is usually adjusted to maintain 30 to 40 percent relative humidity, and therefore keeps the humidifier off during cooling opera tion when the humidity is higher. TEMPERATURE CONTROL IN HOT WATER SYSTEMS Hot water heating systems permit use of relatively simple automatic temperature control for the purpose of reducing operating costs and providing comfortable temperatures. On installations not requiring different supply-water tem peratures simultaneously and where the'boiler is not used to heat domestic hot water, outdoor reset control of the supply-water temperature may be obtained by direct con trol of the burner from a thermostat that is located in the boiler water and is reset in accordance with outdoor tem peratures. A seperate high limit control should be provided. In systems using converters for a hot water supply, a controlling thermostat actuated by the leaving water tem perature modulates the heat-source to the converter. The set point of this supply-water thermostat can be readjusted in accordance with outdoor temperature. In some systems a boiler or converter supplies water at a constant temperature, and three-way mixing valves are used to supply water at different temperatures for various uses or to multiple zones. In these cases, a three-way mixing valve under control of a thermostat in the valve discharge blends boiler water with return water to provide supply water at the desired temperature. The control setting of this thermostat in the valve discharge can be reset in ac cordance with outdoor temperatures. On systems using outdoor-reset supply water and lowered night or week-end temperatures, provision should be made for warmup on restoration to day or normal operation. This can be accomplished by a program control, a warmup space thermostat, or some similar means of providing higher than normal water temperatures during the warmup period. A measure of control can also be accomplished by use of a room thermostat to operate the burner. This type of control i3 applicable only to residences or very small commercial installations, where there is no great difference in heating requirement throughout the building. Where a difference in heating requirements throughout the building does exist, it is advisable to control the supply-water temperature with provision for automatic control or manual adjustment of heating unit output in individual spaces. Economical zone control can be obtained by separate return or supply piping for zones, with a zone thermostat to operate zone pumps or automatic valves. The piping for each zone should be isolated to avoid a common return Ime, because in many cases the return water from one zone is warmer than required for the supply water to another zone. 624 CHAPTER 43 1959 Guide The control of air-handling units in a hot water heating system requires careful consideration. Where the piping re quired is within economical limits, it is advisable to use a three-way nil-ring valve and a pump in the coil circuit (see Fig. 19, Chapter 28) to achieve control. This arrangement provides a constant flow to the coil while the temperature of the water to the coil is varied by changing the mixture of supply water and return water. If impracticable to use 'separate three-way valves and pumps for each coil, it is necessary when varying the flow to a hot water coil to use control valves with plugs or discs designed for close control of flow. They should also be sized accurately for the flow re quired by the coil at a pressure drop as large as the pump and the piping system will permit. Face and bypass dampers to vary the flow of air over a coil with constant water flow can be used in the control of air-handling units. Precautions should be taken to prevent the freezing of water in a hot water heating system whenever design out door temperatures are lower than approximately 20 F, par ticularly if the system is to be operated on an intermittent hftcig as in schools where normal operation is not required on Saturdays or Sundays or during vacation periods. In selecting a means of freeze protection, consideration should be given to the type of system as well as outdoor tempera ture. For iwsfaui**, an air-handling unit to heat outdoor air must have the coil protected for 32 F, whereas supply mains and radiation usually are not subjected to freezing tempera tures until the outdoor temperature drops considerably be low 32 F for extended periods. Intake dampers on air handling units that heat outdoor air should be interlocked with the fan motor so as to dose whenever the fan is not running. Provision should be made to dose the outdoor-air intake and/or stop fan operation if the water circulating in the coil drops below a safe temperature leveL The pos sibility of water freezing in the mains can be minimized by using an outdoor thermostat to provide continuous circula tion of the water whenever the outdoor temperature drops below approximately 30 F. Another arrangement uses an interval timer and outdoor thermostat to provide inter mittent cycling of the circulating pump whenever the out door temperature drops below some predetermined tempera ture. A thermostat in the-retum water at the boiler can be used to start the burner or other heat source if the tempera ture of the return water drops to about 40 F. See Chapter 43 for general information on controls. ZONE CONTROL OF STEAM AND WATER SYSTEMS This section is concerned with zone controls for steam or hot water haating systems. Refer to Part II of this chapter for a general discussion of zoning. Most zone control systems are designed to supply beat to a zone at' a rate equal to the heat loss. This rate of heat input may be established by room thermostats, by controllers responsive to outdoor conditions, or by a combi nation of both. The outdoor controller responds to tem perature and may respond to solar radiation and wind velocity and direction. Features which may be added to the basic zone control system include: 1. Means for automatically or manually, varying the heat input to the zone to compensate for variations in internal heat gain. The automatic arrangement requires a thermostat at. a representative location within the zone. The manual arrange ment usually consists of a switch located where convenient. 2. Means for maintaining a lowered economy temperature or shutting off the heat completely at night of at other times when the zone is unoccupied. This may be accomplished manually - or by means of a clock. 3. An arrangement providing rapid warm-up following a period at the nonoccupancy temperature. During this warm up period full heat may be admitted to the system or the heat input may be controlled at a higher-than-normal rate. The warm-up may be accomplished by a manual switch or may be part of the clock program. A warm-up thermostat located within the zone may be arranged to terminate the warm-up period independently of the switch or clock when the zone approaches the desired occupancy temperature. 4. A manual switch to provide full heat or no heat inde pendently of other controls and to permit manual selection of the various clock functions. 5. Means for shutting off the heat completely when the out door temperature reaches a point where heat no longer is needed. '- 6. A high-limit thermostat in the zone to shut off the heat completely when the zone becomes overheated. Steam: Zone Distribution ' In continuous-flow steam systems the quantity of steam supplied to the zone is varied in accordance with the de mands of the control system. To obtain equalized distri bution of the steam, metering orifices are generally required on the inlets to all radiators or convectors. Supplementary controls for low heat output are often desirable. The follow ing two arrangements are common: 1. Varying the difference in pressure between the supply nri return which results in partially filling the heating units in accordance with demand. This method can be used on atmospheric or vacuum return systems. 2. Varying the pressure in the system while maintaining a constant differential pressure between the supply and return. This results in the heating units being filled with steam at a temperature which is proportional to demand. A vacuum pump maintaining a vacuum slightly below tiie simply pressure is re quired, ana vacuums as high as 20 in. Hg during mild heating weather are common. In intermittent systems steam at full pressure is supplied intermittently to the zone, the length of the on and off periods being varied in accordance with the demands of the control system. Two common arrangements are: 1. A timing device controlled by an outdoor thermostatic element. This can be used to vary the on-off periods-of boiler operation or the opening and closing of a steam valve as a function of outdoor temperature. - 2. A control responding to an outdoor element and an element attached to a radiator or convector. This control varies the length and frequency of the on-off intervals in such a way that the radiator or convector temperature is varied in accordance with outdoor temperature. For proper operation of zone control equipment the heating system must be carefully designed and installed, and maintained in good operating condition. Vents, traps, vacuum pumps, and valves must be given a careful in spection and repaired or replaced when required. Piping must be of adequate size, graded, and dripped. Return piping must be vented and any pockets or lifts removed. Water: Zone Distribution A wimnn method of obtaining zone control of hot water systems consists of varying the temperature of water supplied to the zone inversely as the outdoor temperature varies. This may be accomplished by a submaster ther mostat in the zone supply line readjusted by an outdoor master thermostat, or by a single controller having one Automatic Control 625 measuring element in the supply line and another compen sating element outdoors. On single-zone installations the controller may actuate the burner directly as shown in fig. 25. If the boiler is also used for domestic hot water - the controls may be arranged as in fig. 26. In this case the boiler is controlled at a fixed temperature and the zone controller is arranged to operate a valve to proportion hot water from the boiler with cooler return water to obtain the desired zone water temperature. On multiple-zone in stallations the boiler usually is controlled at a fixed tem perature, and each zone is controlled by a separate valve and-outdoor compensated controller. Each zone should be equipped with a separate pump because in many cases the - (Limit and primary control* not thown) fig. 25.... Control of Hot Water Heating Without Domestic Hof Water Service - (limit and primary control* not dwnj Kg. 26.... Control of Hot Water Heating With Provisions for Domestic Water Heating return water from some zones is warmer than the re quired supply water for other zones. By using individual zone pumps the returns can be separated and thus prevent overheating that would otherwise occur. To compensate for variations in internal load, the action of the zone control may be modified by a room thermostat in each zone which either starts and stops the zone pump, modifies the relationship between outdoor temperature and water temperature, or operates an automatic valve in the zone supply or return line. Each zone may be farther sub divided by providing a separate thermostat and valve for each subdivision. Another zone control method for hot water systems con sists of maintaining a constant water temperature and varying the volume of water supplied to the zone by means of a room thermostat which either starts and stops the zone pump or operates a two-position valve in the zone supply or return line. ' Whenever flow control valves are employed in water circuits it is necessary to employ a relief valve or pressure regulating valve in a bypass connection around the pump. TERMINAL EQUIPMENT Control applications to the following'types of terminal equipment are described in their respective chapters: Radiant Panels--Warm Air Ceiling Panels, Chapter 18 --Hot Water Panels, Chapter 30 --Electric, Chapter 30 and 17 Snow Melting, Chapter 49' Unit Heaters, Chapter 15 Unit Ventilators, Chapter 15 - Unit Air Coolers, Chapter 16 Induction Units, Chapter 19 Dual-Duct Mixing Units, Chapter 19 Room Fan-Coil Units, Chapter 19 Reheat Coils for Individual Spaces, Chapter 19 Classroom Heating and Cooling Units Controls for winter beating and ventilating are essentially the same as for classroom unit ventilators as described in 'Chapter 15, Unit Ventilators and Unit Heaters, except that face and bypass dampers are usually added. The supply hot water temperature should be varied inversely with out door temperature for best results. The space thermostat operates the face and bypass dampers, coil valve, and the outdoor- and return-air dampers. When the system water is changed from hot to chilled water the controls are reversed. For summer cooling the outdoor-air damper opens to a fixed position to admit the required percentage of outdoor air when the fan motor is started. The space thermostat is now reverse-acting and operates only the face and bypass dampers at the cooling coil while the valve remains open. Radiators and Convectors . When individual room control is used each radiator and convector is equipped with an. automatic control valve. Depending upon the size of the room one thermostat may control one or several valves in unison- Volume Damper or Single-Duct Units When individual room control is used each volume damper is equipped with an operator. Often several air outlets are supplied through one damper. The damper operation is usually controlled by a room-type thermostat. The volume damper is usually set to provide for minimum ventilation requirements regardless of thermostat demand. When the airsupply system is used for heating as well as cooling it is necessary to use a heating-cooling thermostat. RESIDENTIAL HEATING AND AIR CONDITIONING The control equipment function in the residence may vary from the regulation of a coal-fired heating plant to the completely automatic control of a year-around heating and cooling system. Regardless of the type of heating or air conditioning system used, the control system should be selected carefully to insure safety and comfort of the oc cupants as well as economy of operation. The simplest type of domestic control is one in which the room thermostat starts and stops the burner, as de scribed in the preceding section. It may be used on gravity or forced-warm air, hot water or steam systems. In forced 626 CHAPTER 43 1959 Guide warm air or forced hot water systems the fan or circulator usually is controlled by a thermostat in the furnace or boiler *nH runs whenever the air or water temperature is above a minimum value, as discussed in Chapter 26. If- straight two-position control is used for this application, the on and off periods are relatively long and there is a tend ency towards cold drafts on the floor during off periods. If timed two-position control is used, the burner may be cycled (started and stopped) often enough to provide re sults very comparable to proportioning control. The heat input to the home is proportioned continuously to the beat loss from the home. The fan of a forced warm air system or the circulator of a forced hot water system may be run almost continuously, thus minimizing the possibility of cold drafts. Proportional control is used on residential applications when provisions are maHa for it in the design of the system. Face and bypass dampers on warm air systems, throttling valves on steam systems and three-way mixing valves on hot water systems are typical examples of controlled devices which permit proportional control. With these arrangements the burner usually is controlled by a thermostat in the furnace or boiler. Proportional control will permit nearly continuous circulation of warm air or hot water, thus re ducing cold drafts. . - Automatic night set-back through the use of a day-night type room thermostat is a refinement frequently added to residential control systems. Though opinions vary regarding the amount of fuel that can be saved by automatic night set-back, tests made both in the warm air heating research residence and the I = B = R research home at the Uni versity of Tllinnig indicate that, on thermostatically con trolled systems, a possible fuel saving of from 7 to 10 percent may be obtained by reducing the house tem perature 6 to 10 F from about 10:00 pm. to 5:30 am. It is often desirable to divide the house into two or more zones for greater accuracy of control and comfort. F>u-h zone may then be maintained individually at the desired temperature level. The division into zones should be based upon exposure or occupancy; the most common division is usually found to be (1) the living section such as living room, dining room, den; (2) the deeping section;. (3) the service section such as kitchen, pantry, servants' quarters; and (4) recreational areas. Further discussion of zone control principles has been given in Part II of this chapter. Year-round residential air-conditioning systems which provide for halting in winter and cooling in summer should be given the wme consideration in selecting the control system as required for commercial air-conditioning systems. See Chapter 19. The basic principles are the same and the final results must provide for the comfort of the occupants. A reduction in investment for automatic controls may re sult in wasteful operation of the system and discomfort for the occupants. Special thermostats have been designed to take care of the year-round residential air-conditioning systems. These thermostats offer manual, semi-automatic, and automatic change-over from heating to cooling as selected by the unit manufacturer. Generally speaking, the heating unit is controlled by timed two-position action and the cooling unit by straight two-position action. Some form of humidity control may be added. When an add-on unit is installed to obtain a year-round air-conditioning system by. change of a straight heating system, it may be controlled separately or integrated with the heating control system. However it is accomplished, the control system should be simple enough for the user to understand how to operate it effectively. REFERENCE . 1E. J. Brown and J. R. Fellows: Pressure losses and flow characteristics of multiple-le&f dampers (ASHAE Jooenai. Section, Heating, Piping and Air Conditioning, August 1957, p. 119). BIBLIOGRAPHY Automatic Control Terminology (American Society of Me chanical Engineers, 1954). R. H. MacMillan: An Introduction to the Theory of Control in Mechanical Engineering (Cambridge University Press, New York, 1951). . E. W. F. Feller: Instrument and Control Manual for Operating Engineers (McGraw-Hill Book Co.. New York, 1947). J. E. Haines: Automatic Control of Heating and Air Con ditioning (McGraw-Hill Book Co., New York, 1953, 1st ed.). Save Fuel for Victory (University of Illinois, Engineering Experiment Station Circular Series No. 47, p. 31). CHAPTER 44 INSTRUMENTS AND MEASUREMENTS Temperature Measurement, Pressure Measurement, Air-How Measurement, Air Change Measurement, Measurement of Air Currents, Humidity Measurement, Measurement of Mean Radiant Temperature, Heat Transfer Through Building Materials, Combustion Analysis, Smoke density Measurements, Sound and Vibration Measurements, Determination of Air Contaminants EATING and air-conditioning engineers and techni 4 -- the temperature of the bath. H cians require instruments for both laboratory and field t, = the average temperature of the emergent liquid column use. Somewhat more precision is attainable and essential in of n degrees. the laboratory, where research and development are under taken, than in the field, where acceptance and adjustment tests are conducted. The purpose of this chapter is to de scribe briefly some of the more important instruments, and to outline their uses and characteristics. A thermometer can be appreciably affected by radiation - from surrounding surfaces. If the temperature to be meas ured is approximately the same as that of the surrounding surfaces, radiation effects may usually be ignored. If the tem perature being measured differs considerably from that of TEMPERATURE MEASUREMENT1-1 the surroundings, steps should be taken to minimize the ef fect of radiation.1 This is usually accomplished either by Thermometers shielding or by aspiration. Shielding is accomplished by plac Any device capable of indicating temperature is a thermom eter, but in common usage the term thermometer without qualification has come to signify the ordinary'liquid-in-glass temperature indicating device. Mercury-filled thermometers have a useful range from --40 F, the .freezing point of mer cury, to about 1000 F, at or near which the glass usually softens. Lower temperatures can be measured with alcoholfilled thermometers for which the range is about --94 F to +248 F. The better thermometers have their scales, either Fahrenheit or Centigrade, etched with acid into the glass which forms their stems. Thermometers are calibrated during manufacture for at least two temperatures, frequently the freezing and boiling points of water, and the space between the calibration points is then divided into the desired scale divisions. The probable error for etched stem thermometers is plus or minus one scale division. For precise work, recalibration is frequently necessary to determine the proper corrections to be applied ing highly reflective surfaces between the thermometer bulb and the surrounding surfaces. However, this must be done in such a way that air movement around the bulb is not ap preciably restricted.4 Improper shielding may increase rather than decrease errors. Aspiration is accomplished by drawing a high-velocity stream of air or gas over the bulb of the ther mometer. Industrial-type thermometers are available for permanent installation in pipes or ducts. These instruments are fitted with metal guards to prevent breakage, and are useful for many purposes. However, the considerable heat capacity and conductance of the guards or shields may introduce er rors. To prevent errors in temperature measurements, ample time should be allowed for the thermometer to attain tem perature equilibrium with the surrounding fluid. In reading a thermometer, the eye should be at the same level as the top of the liquid column to avoid parallax. to the scale readings. Thermocouples Liquid-in-glass thermometers are calibrated by the manu facturer for either complete or partial stem irrnnargmn If a thermometer which has been calibrated for complete im mersion is used at partial immersion, that is, with a portion of the liquid column at a temperature different from that of the bath, an emergent stem correction should be made. This correction may be calculated by Equation 1: Stem correction = Kn (tt -- t,) (l) When two wires made of dissimilar metals are joined by soldering, welding, or merely by twisting, a thermocouple or thermo-junction is formed. An electromotive force, which de pends upon the temperature of the junction, is found to exist between the wires. When the wires are joined at two points a thermocouple circuit is formed. If one junction is kept at a temperature different from the other, an electric current flows through the circuit due to the difference in emf devel where oped by the two junctions. This phenomenon is employed for temperature measurements in thermocouple systems, one K " the.differential expansion coefficient of the mercury or junction being ordinarily kept at a constant temperature, as other liquid in the glass. K may be taken as 0.00016 for in an ice bath, while the other junction is placed at a point at Centigrade mercurial thermometers and 0.00009 for which it is desired to observe the temperature. In practice it Fahrenheit mercurial thermometers. For values of K is desirable to utilize emf to indicate temperature because, at for other liquids and for specific glasses, see Reference small or zero current flow, the resistance of the circuit is un important. A high resistance millivolt meter is useful in some n = the number of degrees of the liquid column emergent from the bath. cases but the potentiometer yields better results. In the po tentiometer the electromotive force generated by the thermo 627 628 CHAPTER 44 1959 Guide couples is balanced against an electromotive force from the battery so that observations are made with no flow of cur* rent through the thermocouple circuit. A conventional ar rangement is illustrated in Fig. 1. The thermocouple- leads A-B are so connected that their polarity opposes that of bat tery C. If the position of E on the graduated slide wire rheo stat DF is adjusted until galvanometer*(? shows 'no current flowing, resistance DE will indicate directly the voltage gen erated by the thermocouple. In order to calibrate the instru ment, switch S is thrown over to the standard cell circuit while rheostat R is adjusted so that the galvanometer shows Eero current. Battery C then exerts the known voltage of the standard cell at Dff. The act of adjusting rheostat D-F (Fig. 1) for zero current flow is known as balancing the potentiometer. Automatic self fig. 1.... Basic Grcuit and Connections for Thermocouple and Potentiometer hfllanr.ing instruments of both the indicating and recording types are on the market. They usually contain an automati cally compensating cold junction to avoid the use of an ice bath, and special thermocouple wire is furnished with them from the factory. - The choice of materials for thermocouple wire is deter mined by the temperature to be measured,- the protection from corrosion afforded the couple, and the precision and service life required. In general, copper vs. constantan is suitable for temperatures up to 700 F, iron vs. constantan up to 1500 F, and chromel vs. alumel up to 2200 F. Higher tem peratures require the use of noble metal thermocouples (plati num vs. platinum-rhodium). In addition to the higher initial cost of a noble metal couple, it does not develop as high an emf as the base metal couples do. Impurities make large dif ferences in the performance of thermocouple wires and for this reason calibration of samples from each spool of wire is essential for precise work. Data on wire can usually be ob tained from the manufacturer. .With a suitable potentiometer, small wires serve as well for thermocouples as large ones, and the fineness of the wires is limited only by consideration of mechanical strength and convenience in handling. Small couples respond more promptly to changes in temperature and are less affected by radiation than large ones. Heavy gage couples, however, ore necessary for high temperature work where corrosion of the wire is a problem. For use in heated air or gases, thermo couples are often shielded,' as are thermometers, and aspi rated thermocouples are sometimes used. An arrangement has been described for avoiding error due to radiation. It in volves the use of several thermocouples of different wire sizes, the true temperature being estimated by extrapolation of readings to zero diameter* By the use of thermocouples, temperatures at remote points may be indicated or recorded on conveniently located instru ments, and temperatures may be obtained within thin mate rials, narrow spaces, or otherwise inaccessible locations. 'Thermocouples in series;-with every alternate junction maintained at a common temperature, will produce an emf which, when' divided by the number of couples, gives the average emf corresponding to the true average temperature. This series arrangement' of thermocouples, often called a thermopile, can have extreme sensitivity and is useful in de tecting very small changes in temperature. Thermocouples in parallel, having the similar metals of a number of couples connected together and run to a common cold junction, will cause an indication on a potentiometer which is the true average emf only if the electrical resistances of the parallel circuits are the same.'* * . The thermocouple, is particularly useful in determining a surface temperature. It may be attached to a metal surface in any of several ways. For permanent installations, solder ing, brazing, or peening may be desirable. A small hole is drilled for the peening operation; the thermocouple is in serted and the metal is peened to retain it. The fact that the thermocouple is in electric contact with the surface is unim portant in usual circuits. For temporary arrangements, cou ples may be attached by means of surgical or cellophane tape. For boiler or furnace surfaces, furnace cement serves very well. To minimize the possibility of error due to heat conduc tion along the wires, a surface thermocouple should be made of fine wires, and the wires should be held in close contact with the surface for an inch or so from the junction. Electri cal insulation between the wires must be perfect except at the junction. Resistance Thermometers - Resistance thermometers depend for their operation upon, the change of electric resistance of metal with change in tem perature. The resistance generally increases with rising tem perature. Their use largely parallels that of thermocouples, although readings tend to be unstable above 950 F. Two-lead temperature elements are not recommended, since they do not permit correction for lead resistance. Three leads to each resistor are necessary to obtain consistent readings. A typical circuit used by several manufacturers is shown in Fig. 2. In this design a differential galvanometer is used, in Fig. 2.... Typical Resistance Thermometer Grcuit and Connections Instruments and Measurements 629 which coils L and H exert opposing forces On the indicating needle. Coil L is in series with the thermometer resistance AB, and coil H is in series with the constant resistance R. As the temperature falls, the resistance of AB decreases allowing more current to flow through coil L than through coil H. This an increase in the force exerted by coil L, pulling the needle down to a lower reading. Likewise, as the temperature rises the resistance of AB increases, causing less current to flow through coil L than through coil H. This forces the in dicating needle to a higher reading. Rheostat S must be ad justed occasionally to maintain a constant flow of current. As compared to the thermocouple, the resistance ther mometer does not require a cold junction, and it can be simply scaled for more accurate measurements; but; gen erally because of its construction it is more costly and is apt to have considerable- lag. It gives best results when used to measure steady or slowly changing temperature. For accurate results the entire thermometer coil must be exposed to the temperature to be measured, i, Pyrometers The pyrometer is the usual instrument for measuring high temperatures such as those of incandescent bodies or furnace interiors. There are two ` types. In the radiation pyrometer the radiant energy from an observed surface falls on a thermopile, and the emf generated by the pile, measured by a galvanometer or potentiometer, is an index of the surface temperature. With the optical!pyrometer a narrow spectral band, usually red, emitted by the surface, is matched visually with the filament of a special electric lamp. The emf necessary to cause the filament to match the surface in brightness is the index of the temperature of the surface. Pyrometers are calibrated by means of various metals with known-melting or freezing points. Portable as well as laboratory models are manufactured. Color Indicating Crayons - Crayons are available, the marks of which change color or melt at specified temperatures. Such crayons have been sold in boxes covering the range from about 100 F to about 800 F in 100 deg steps,.with a precision of some 10 deg. They are a rough but convenient means of determining temperatures, and of locating isothermal lines on surfaces below red heat. ' . PRESSURE MEASUREMENT Pressure Gages The Bourdon is the most common type of-pressure gage, and its appearance probably is familiar to anyone having an acquaintance with power plants or laboratories. The essential element of such a gage is the Bourdon tube, a metal tube of oval cross-6ection curved along its length to form an almost complete circle. One end is closed and the other is connected to the vessel in which the pressure is to be measured. With an increase of pressure, the tube tends to straighten, and vice versa. The resulting motion of the closed end is communicated by suitable linkages to a needle moving over a'graduated dial. If the range is above about 20 psi, such gages are usually calibrated by means of a dead weight tester, whereby known pressures are produced in a fluid by imposing known weights on a piston of known area. Suction gages and pressure gages with ranges below about 20 psi are ordinarily calibrated against mercury manometers. Gages are commonly sct to read accurately at or near the pressure of probable use. Gages of several different types or qualities are available on the market.* Manometers The manometer is a ample and useful means for measur ing partial vacuum and low pressure. It is, moreover, a ' primary instrument; it does cot require calibration, and it is often used as a standard for the calibration of other instruments. It is so universally used that both the inch of water and the inch of mercury have become accepted units of pressure measurement. In its simplest form, the manometer consists of a U-shaped glass tube partially filled with a liquid. A difference in height of the two fluid columns denotes a difference in pressure in the two legs, which is proportional to the difference in height. For converting manometer readings iDto other pressure units, certain proposed standard factors are applicable for precise work. These are based on a standard gravitational acceleration of 32.1740 ft per (sec) (sec) and are as follows: .1 Standard Atmosphere = 14.696 lb per sq in. = 29.921 in. mercury at 32 F = 33.96 ft water column at 68 F For most ordinary purposes, the following figures are of ample accuracy: 1 Atmosphere *-14.7 lb per sq in. " 29.9 in. mercury.TM 34.0 ft (408 in.) water column . Manometer tubes should be chemically clean. The bore is not important, except insofar as it affects the meniscus through wetting or surface tension. Bores of at least Me in. for rough, and V in. for more precise, measurements are recommended. Liquids other than water are sometimes used for low-pressure measurement and, when this is done, the readings must be corrected for the density of the fluid. For measuring pressure differences of a few. inches of water, or les, U-gages are often set at an angle for scale amplification. In many gages of this type, commonly termed draft gages or inclined manometers, only one tube of small bore is used and the other leg is replaced by a reservoir. The scale is calibrated to read in inches of water, and it is necessary to use a fluid having the same gravity as that for which the gage was originally calibrated, or to apply a correction if another fluid is used. Such gages may be checked one against another. For more accurate calibration the gage may be checked against a micromanometer or a calibrating device known as a hook gage.** The accuracy of a draft gage is dependent on the dope of a tube, and consequently the base of the gage must be leveled care fully. It is not desirable to use a slope of less than 1 in 10. Where pressures are read under extreme conditions of temperature, and calibration is possible only at normal tem perature, it. is necessary to correct for the change in density of the liquid in the manometer.11 For measuring low-pres sure differences to within 0.001 in. of water, very sensitive micromanometers are available, such as the Illinois or Walden,1* and the Emswiler." Various instrument manu facturers are also prepared to furnish accurate micromanom eters. Barometer The simplest and earliest type of barometer consists of a glass tube somewhat more than 30 in. long filled with 630 CHAPTER 44 1959 Guide mercury, and inverted in a cup partially filled with mer cury. The height of the mercury column in the tube above the mercury surface in the cup is a measure of the existing atmospheric pressure, except for the slight pressure of the mercury vapor in the space above the mercury in the tube. This can ordinarily be ignored. Elaborate mercury barometers, fitted with vernier scales, are available. For precise work, corrections must be made for the thermal expansion of the mercury and of the scales." The instruments are usually calibrated for 32 F mercury and 62 F scale temperature, and the correction C to be sub tracted from the observed barometer's height is obtained by means of Equation 2. hit - 28.630) (1.11231 - 10978) (2) where C " correction to be subtracted, inches of mercury. h -- observed height, inches of mercury. ( -- observed temperature of the barometer, Fahrenheit degrees. Standard atmospheric pressure at sea level is 29.921 in. Hg, and since normal atmospheric pressure decreases about 0.01 in. Hg for each 10 ft increase in elevation, it is im portant to make a correction if the elevation of the ba rometer is not that of the test apparatus. In many cases the barometric reading may be obtained from a nearby Weather Bureau Station, in which case inquiry should be made as to whether the value is for station or sea level pressure.- Atmospheric pressure may also be measured by an aneroid barometer which is easily portable. In this type, variations in atmospheric pressure deflect the thin surface of a sealed diaphragm capsule. Most commercially available aneroid barometers are not as accurate as the mercurial type, and the best require occasional recalibration. Open-scale aneroid barometers are more expensive than common mercurial ba rometers. ' Most of the pressure gages used in engineering work indicate gage pressures, that is, the difference between the pressure bong measured and the atmospheric pressure. Such pressures are called gage pressures. Absolute pressure may be obtained by adding barometric pressure and gage pressure algebraically. AJR-aOW MEASUREMENT The theory of various means for measuring the flow of fluids is rfificufiserf is Chapter 4 Fluid Flow. Heating and air-conditioning engineers are called upon to measure the flow of air more often than that of other gases, and usually the air is measured at or near atmospheric pressure. Under this condition, the air can be treated substantially as an incompressible fluid which implies that simplified formulas can1 be used with sufficient accuracy for the solution of ' many problems.1* The Pitot Tube The Pitot tube, used in conjunction with a suitable ma nometer, provides a simple method of determining the air velocity in a duct. The construction of a Standard Pitot Tube," and the method of connecting it to a draft gage is shown in Fig. 3. The equation for determining the air velocity from the measured velocity pressure is as follows: V (3) where V = velocity, feet per minute. -- velocity pressure (Pitot tube manometer reading), ' inches of water. ' p =* density of air, pounds per cubic foot. ' Since the velocity in a duct is seldom uniform across any section, and since a Pitot tube reading indicates a velocity at only one location, a traverse is usually made to determine the average velocity so that the flow can be computed. In general, the velocity is lowest near the edges CQUAL. (MCtuTIIC ' WTVT nK SBTWS I--JJCU tY o Hg. 4 .... Pitot Tube Traverse for Round and Rectangular Ducts or corners, and greatest at or near the center. Suggested Pitot tube locations for traversing round and rectangular .ducts are shown in Fig. 4. In round ducts not less than 20readings should be taken {dong two diameters at centers of equal areas as shown. In rectangular ducts the readings should be taken in the center of equal areas over the cross section of the duct. The number of spaces should not be less than 16, and need not be more than 64. When less than 64 are -taken, the number of equal spaces should be such Instruments and Measurements 631 that the centers of the areas are not more than 6 in. apart. In determining the average velocity in the duct from the p density of air, pounds per cubic foot. K = orifice or nozzle coefficient. readings given, the calculated individual velocities or the square roots of the velocity heads must be averaged. It is incorrect to use the average velocity head for this purpose. Pulsating or disturbed flow will give erroneous results and therefore, if possible, the Pitot tube should be located , at least lYt diameters downstream from a disturbance such as that caused by a turn. Straightening vanes" located Wt duct diameters ahead of the Pitot tube will serve to im prove the precision of the measurements. . The type of manometer to be used with a Pitot tube depends upon the magnitude of the velocity pressure being measured and the accuracy desired. At velocities greater than 1500 feet per minute, a draft gage of appropriate range is usually satisfactory. If the Pitot tube is being used ' to measure low air velocities, a precision manometer of some type is essential. ' ' Many forms of Pitot tubes, other than the one described, have been used and calibrated." A double-ended tube," one end pointing downstream, and one upstream, is some times used for low velocities,' but it should be carefully calibrated for accurate results. A special form of this tube design consists of two straight 14-in. tubes soldered to gether, closed at the end, and with a 0.04 in. hole in each tube opposite the line of contact. This tube is useful in exploring velocities in exhaust inlets, such as hoods placed around grinding wheels. To meet special conditions, different The discharge coefficient K for an orifice is approximately 0.60, and for a nozzle is approximately 0.95. Correct values of K for various diameter ratios, pressure tap locations, and Reynolds numbers are given in Chapter 4. In some in stances nozzles are used in multiple so that the capacity of tire testing equipment can be changed by shutting off the flow through one or more nozzles. An apparatus designed for testing the air flow and capacity of air-conditioning equipment is described by Wile" in an article in which pertinent information on nozzle discharge coefficients, Rey nolds numbers, and the resistance of perforated plates is also presented. Such apparatus in some laboratories is com monly referred to as a code tester. The Venturi- meter is like the nozzle, except for the ad dition of a downstream transition section that reduces the pressure drop through the measuring apparatus. In some cases air flow through a heater coil or heating unit may be estimated by computation from the heat given up by the coil, and the temperature rise (measured by thermocouples) of the air passing through. It is essential to have a uniform flow over the entire inlet and outlet of the heater at the planes of temperature measurement, and temperatures must be taken at enough points to provide a good average. Propeller or Revolving Vane Anemometer sized Pitot tubes which are geometrically similar to the standard tube can be used. The propeller or revolving vane anemometer consists of a light revolving wind-driven wheel connected through a Orifices and Nozzles gear train to a set of recording dials -that read the linear feet of air passing in a measured length of time. It is made Application of the Pitot tube is often inconvenient when in various 3 in., 4 in., and 6 in. bung most common. velocities are low, because the resultant velocity pressures FAe.h instrument requires individual calibration. At low become so small that extraordinary means are necessary velocities the friction drag of the mechanism is consider for measuring them. In addition, velocity surveys of^the able. In order to compensate for this, a gear train that whole cross-sectional area of a duct are-inexpedient when overspeeds is commonly used. For this reason the correc numerous test runs are in prospect. Chiefly for these reasons tion is often additive at the lower range and subtractive orifices are used in many test and research applications. at the upper range, with the least correction in the middle Plate or square-edge orifices"* " are ample to construct range of velocities. Most of these are not sensitive enough and convenient to use. They may be mounted between for use below 200 fpm. flanges, and a set of orifices of different sizes may be made readily interchangeable to measure a wide range of air-flow Deflecting Vane Anemometer rates. The proportions of standard orifices and nozzles are given in Chapter 4. Several standard arrangements of pressure taps for use with orifices are described in Chapter 4. Where velocities are low or where flow is free of large eddies and parallel to the walls of the duct, a drilled hole cleared of burrs and at a right angle to the stream is satisfactory." For higher velocities it is common practice to provide four or more holes around the periphery of the duct and connect them into a manifold. To determine air flow by means of an orifice or nozzle, the pressure drop across the device is measured. The flow rate may then be calculated by means of the equation. The deflecting vane anemometer consists of. a pivoted vane enclosed in a case. Air exerts a pressure on the vane as it passes through the instrument from an upstream to a downstream opening. The movement of the vane is re sisted by a hair spring and a damping magnet. The instru ment gives instantaneous readings of directional velocities on an indicating scale. With fluctuating velocities, it is necessary to average visually the swings of the needle to obtain average velocities. This instrument is-very useful for studying motion of the air in a room," and.in locating objec tionable drafts. Various attachments are available, such as the double tube arrangement for determining velocities in ducts, and a device for measuring static pressures. Each instrument, and the attachments for it, must receive in dividual calibration. For determining average velocity in a duct, it is necessary to traverse the duct as is done when where using the Pitot tube. Q -- air flow, cubic feet per minute. , Thermal Anemometers At = area of the orifice or nozzle, square feet. If a suitable sensing element is heated electrically at a . h " pressure drop across orifice or nozzle, inches of water. fixed rate and exposed to an air stream, the temperature 632 CHAPTER 44 1959 Guide difference between the element and the stream becomes a measure of velocity by calibration. In the hot-wire ane mometer, a very fine heated wire is employed as a resist ance-thermometer element whose temperature, may be de termined accurately.*1, *" In the heated-bulb thermometer type, a hpgf.ing wire is wound around the bulb of a mercuryin-glass thermometer, and the temperature difference be tween this thermometer and a similar unheated one serves as an index of air speed.1* The heated-thermocouple ane mometer is calibrated to give velocity in .terms of the dif ferential emf between heated and unheated thermo-junc tions exposed to an air stream.** * Combined measurements of air temperature and velocity are particularly useful for air distribution studies, and automatic recording poten tiometers or resistance-thermometer devices facilitate spa tial traverses. A correct calibration of thermal anemometers requires consideration of the effects of temperature, hu midity, and pressure upon the air properties which in fluence convective beat transfer* With sensing elements of simple shapes for which convection data are known, thermal anemometers may be designed, both thermally and electrically, for desired characteristics. Directional sen sitivity is controllable. Thermal anemometers are convenient and practical for low velocities. Cup Anemometer The cup-type anemometer is almost universally used for measuring wind speeds. It consists of three or four hemi spherical cups mounted radially from a vertical shaft. Wind from any point of the compass will cause the cups and shaft to rotate. The instrument is usually so constructed that wind speeds may be recorded or indicated electrically at some remote point. Measurement of Velocities at Inlets and Outlets of Ducts In the field it is often desirable to make volume measure ments at the face of the supply openings. For accuracy, the instrument, and its application should be checked on a similar approach and grille in the laboratory before use in the field. Tests have shown that the propeller-type anemometer can be used successfully on most of the common types of supply grilles.** * The core area is divided into equal squares, and the anemometer is held against the face of the grille for the same length of time in each. To obtain the air volume in cubic feet per minute, the average corrected velocity in feet per minute thus obtained is multiplied by the average of the gross and net free area of the grille (core) in square feet. ' On exhaust openings, the anemometer traverse is made as described previously. The air volume may be determined by multiplying the corrected velocity in feet per minute by the gross core area of the grille in square feet, and by a coefficient for average conditions of 0.85." When a propeller-type anemometer is held in a stream of varying velocities, it tends to indicate higher than the' true average, that is, the speed of the propeller is nearer to the top velocity in its area than it is to the minimum velocity. This is the main reason for. the large difference in ratings of unit ventilators by the anemometer method, and by air volume measurements in a duct approach to the inlet* Deflecting vane anemometers can be also used within their range at the. face of supply grilles when properly applied. In principle, it is a case of finding the velocity at many points, and using the average thus found with the correct discharge area at that cross-section. The deflecting vane anemometer equipped with a jet on the end of a rubber tube has been found especially convenient and ac curate on supply grilles." On modem air conditioning grilles, the core area is used without a correction coefficient when the jet is held one inch away from the face of the grille.. At this distance, the constriction due to the thin bars has disappeared, since the small air jets have reunited and the air stream has not yet spread beyond the core dimensions. With deflecting grilles the exploring jet should be turned to the anglft giving a maximum reading. With suitable trav ersing tips and calibration, this instrument may also be used on exhaust grilles if proper grille factors are applied* Those contemplating such measurements should consult the references cited. . MEASUREMENT OF AIR CURRENTS The measurement of air current velocities within an en closed space is usually a tedious undertaking. However, use ful data can be obtained with any of several instruments now available, if they are maintained in calibration, and the user understands their operation and limitations." Ther mal-type anemometers, when calibrated for low air veloc ities, are well suited for this service. The Kata Thermometer Another instrument useful for studying air currents in free spaces is the Kata thermometer. This is essentially an alcohol thermometer with a very large bulb, and with only two scale divisions etched on its stem. On the Low Kata these divisions are 95 and 100 F; on the High Kata they are 125 and 130 F. In use, the instrument is heated, usually in a water bath, until the alcohol has risen suf ficiently above the upper calibration on the stem. It is then thoroughly dried, and placed at the point at which the air velocity is to be measured. The time in seconds required for the temperature to drop from the upper to the lower scale division is observed. From this cooling time and the calibration factor inscribed on each Kata ther mometer, the air velocity can be calculated or determined .from a chart. The Kata thermometer is- also used in de termining the cooling power of the atmosphere, since it loses heat by radiation and convection when dry, and by radiation, convection, and evaporation when the bulb. is equipped with a wetted cloth covering." To minimize the effect of radiation, the Kata thermometer is also made with a silvered bulb. Smoke is a qualitative tool which is very useful in study ing air movements. Satisfactory smoke can be obtained from titanium tetrachloride (which, however, is very ir ritating to nasal membranes) or by mixing potassium chlo rate and powdered sugar (a nonirritating smoke) and firing the mixture with a match. This latter process evolves con siderable heat, and it should be confined in a pan away from flammable materials. The titanium tetrachloride smoke lends itself to spot determinations, particularly for leakage through casings and ducts, as it can be easily handled in a small pistol-iike ejector. The fumes of aqua ammonia and of sulfuric add, if permitted to mix, form a white precipitate which is useful for some purposes. Two bottles, one containing ammonia water and the other add, are connected to a common nozzle by means of rubber tubing. Air is forced over the surfaces of the liquids in the bottles Instruments and Measurements 633 by means of a syringe, and the two streams, upon mixing at the nozzle, form-a white cloud. A satisfactory test smoke may also be made by bubbling an air stream through ammonium hydroxide and then through muriatic add." Smoke tubes, smoke candles, and smoke bombs are available for studying airflow patterns. Infiltration or Air Change Measurement The total dr leakage into an existing building caused by wind and temperature difference forces can be determined with considerable accuracy by determining the decrease m concentration of a tracer gas. Hydrogen and helium have both been used rather successfully as tracer gases in con junction with a sensitive thermal conductivity compara tor"*" About one percent of tracer gas by volume is in troduced into the room or building, and the tracer gas is thoroughly mixed with the air. The decrease in concentra tion of the tracer gas is observed at regular time intervals with a thermal conductivity meter as infiltration dilutes the mixture. The following formula is used to calculate the infiltration from the observed concentration measurements: C - Cjt - . V (5) where C, = initial tracer gas concentration, percent. C concentration of tracer gas after / minutes, percent. v = volume of room or building, cubic feet. k = infiltration rate, cubic feet per minute. e *= 2.718. ` .. Closets and cupboards should be left open during such infiltration tests so the entire space will have the same rate of change of tracer-gas concentration. HUMIDITY MEASUREMENT ' perature is different for ice and for water. Some operators remove the wick from the wet-bulb for freezing conditions and dip the bulb in water a few times, allowing the water to freeze on the bulb between dips and to form a film of ice. Since wet-bulb depression is slight at low temperatures, precise temperature readings are essential. In the ventilated or aspirated psychrometer, the ther mometers remain stationary, and a small fan or blower or - a syringe is used to move the air across the thermometer bulbs. Various designs have been employed in the labora tories, and several commercial models are available. The Dew-Point Hygrometer In the usual form of these instruments, means are pro vided for cooling, and observing the temperature of, a surface which is exposed to air. The temperature at which visible condensation occurs on the surface is considered the dew point of the air. With the dew-point temperature known, the relative humidity and other properties of the air can be determined from tables and charts (See Chapter 3). A bright surface or metallic mirror is usually employed . to improve the visibility of the dew deposit, and various means are used to cool the mirror from the back, including evaporation of ether or another refrigerant, or a stream of air passed through dry ice. Dew-point temperatures, in some cases, are observed by means of thermometers in fluids in contact with the back of the mirror, but in modern instruments thermocouples are used, and are soldered or welded to the mirror itself. The dew-point apparatus is not so commonly used as the psychrometer, probably be cause it is less convenient. It is usable, however, for higher temperatures than the wetr- and dry-bulb psychrometer, and should be considered for dew points near or above the boiling point, as in the case of flue gases. Special ap paratus for high -precision has been constructed, in which the photronic cell and a light source are used for dew or frost detection instead of visual inspection. Psychrometers . * Organic Hygrometers . Any instrument capable of measuring the humidity or hygrometric state of the air is a hygrometer. A psychrom- eter .is a particular kind of hygrometer which consists of two mercury thermometers, one of which has a cloth wick - or sock applied to its bulb. For use, the wick is wetted with distilled water and ventilated-with air moving at a recom mended rate of 900 fpm or more, relative to the instru ment." In the simpler and more common type, known as the sling psychrometer, the two thermometers are mounted side by side on a frame fitted with a handle by which the device can be whirled through the air. The motion is ar rested for reading the thermometers, and continued until the thermometer readings become steady. Due to evapora tion, the wet-bulb thermometer will indicate a lower tem perature than the dry-bulb thermometer, and the difference is known as the wet-bulb depression. Charts and tables are available showing the relation between the thermom eter readings and the humidity.1** "* " Data are usually based on a total pressure of one standard atmosphere. For precise work, a correction is necessary for barometric pres sure and is usually made by multiplying the observed rela tive humidity by the ratio of the observed to the standard atmospheric pressure. ' For air temperatures below 32 F, the water on the wick may either freeze or supercool, and its state must be known and a proper table or chart used, since the wet-bulb tem- Many organic materials change in dimensions with changes in humidity and this action has been utilized in a number of simple and effective humidity indicators, recorders, and controllers. See also Chapter 43 Automatic Control. Mo tion caused by the changes in dimension, through a suitable linkage, causes a pointer to move across an indicating dial, moving a pen across a recording chart, or actuating a pneumatic or electric control mechanism. Common organic materials employed are human hair, animal membrane, animal horn, wood, and paper. Unfor tunately, although the field has been well explored, no organic material has been found which can be relied upon to consistently reproduce its action over an extended period of time. Such devices require initial calibration and frequent recalibration or setting, especially if they are exposed to extremes of either high or low humidity. In spite of this they are highly useful because they read directly in terms of humidity, they are simple and inexpensive by compar ison with most other types, and the inconvenience of re calibration is often less than that of providing distilled water and servicing the wicks of wet- and dry-bulb psy chrometers. Electrolytic Hygrometers The dampness, and therefore the electrical resistance of a salt film, varies with the humidity of the atmosphere to 634 CHAPTER 44 1959 Guide which the film is exposed, and at least two types of instru ments based on this fact have been developed. The Dunmore hygrometer was originally designed for use in radio sondes or gmall balloons, and means were devised whereby the device transmits humidity data back to earth in the form of a radio signal. In the more usual form, this hy grometer consists of a dual winding of small wire on a noneonducting tube. The whole is coated with an elec trolytic film, usually containing a salt such as lithium chlo ride, which forms an electric connection between the wind ings. Means are provided for determining the electrical resistance of the film, which is an indication of the humid ity. In the radio-sonde, variations in the resistance of the film affect the frequency of an oscillating circuit. These hygrometers are usually calibrated by comparison with a wet- and dry-bulb psychrometer. For calibration for some purposes, particularly for use at subzero, temperatures, m^ns have been provided for producing atmospheres of known humidity.0 Advantages of instruments of this type for some scientific and industrial purposes are becoming apparent, and some forms of them are on the market. The Weaver-type hygrometer is particularly useful for determining the humidity of air or other gas in pipes or closed vessels at various pressures and temperatures. It consists of a threaded plug carrying a central electrode insulated from the plug, except for a gelatinous electrolytic film. The film is exposed to the air or gas from the pipe or vessel, and provision is made for determining its electrical resistance. The hygrometer, or detector, is mounted in a manifold equipped with valves whereby the film can be alternately exposed to the test gas, and to a standard gas having a known absolute humidity. The pressure of the ' - standard gas is varied until contact with it establishes the same resistance in the film as the test gas, and the humidity of the test gas is then determined by computation based oh the gas laws. Chemical Hygrometry The humidity of an atmosphere can be measured directly by extracting and weighing the water vapor from a known sample. For precise laboratory work, powerful desiccants such as a sulfuric acid and phosphorus pentoxide are used for the extraction process, while for some purposes, calcium chloride, lithium chloride, or silica gel are satisfactory. Freezing the water vapor out of a measured stream of air or gas with solid carbon dioxide, and weighing the resulting ice, is a similar operation, A thermal conductivity method for gas analysis can be used for temperatures above 212 - F, or for very low humidities.4* MEASUREMENT OF MEAN RADIANT TEMPERATURE Because if its effect on human comfort, it is sometimes desirable to measure the1 radiation exchange between a per son and his surroundings. The radiant environment of a space is usually expressed in terms of its mean radiant temperature (MRT), which is defined in Chapter 1. The Vernon globe thermometer*4, ** is commonly used to measure mean radiant temperature. This instrument con sists of a 6-in. diameter hollow eopper sphere coated with flat black paint and having a thermocouple or thermometer bulb at its center. The temperature assumed by tbe globe at equilibrium is the result of a balance between the heat gained or lost by radiation and the loss or gain by convec tion^ In terms of heat-transfer relationships: TV - 77 + 0.103 X 10* w (t, - Q (8) tohere Tm = moan radiant temperature, Fahrenheit absolute (black-body equivalent). T, " globe temperature, Fahrenheit absolute. V *= air velocity, feet per minute. tt, tm -- globe ambient air temperature, Fahrenheit. It will be noted from the above equation that the air temperature and the air velocity around the globe must a]an be determined. It is the velocity measurement which presents the greatest problem in the use of the globe ther mometer. A two-sphere radiometer* has recently been developed which may be used for the measurement of MRT. This instrument utilizes two spheres approximately 2 in. in di ameter, one of which is gold-plated, and the other black. Tbe two spheres are heated electrically to the same tem perature, thus rfimitiftting differences in convection. The difference in energy required by the two spheres to main tain temperature equilibrium is measured, and from this difference, the MRT of the space may be calculated. Several instruments have been developed to evaluate the combined effect of radiation and convection on human com fort. Among these are the eupatheoscope" and the thermal integrator.0," HEAT TRANSFER THROUGH BUILDING MATERIALS Thermal Conductivity The thermal conductivity (k value) of an insulation, as defined in Chapter 9, is a unit heat-transfer factor. Practi cally universally accepted for the conductivity determina tion of flat insulation is the guarded hot plate, which is described in ASTM test method C-177." In its simplest form it consists of an electrically heated plate and two water-cooled (dates. Two identical specimens or slabs of a material are required for a test, and one is mounted on each side of the hot plate. A cold plate is then pressed against the outride of each specimen by & clamp screw. The heated plate is divided into two portions: tbe central or measuring section, and the outer or guard section. Dur-ing tests the two sections are maintained as nearly as possible at the same temperature. The purpose of the guard section is to minimize errors due to edge effects. The elec tric energy required to heat the measuring section is care fully observed and converted to Btu per hour. From this heat quantity, the area of the test section, the temperature gradient, and the specimen thickness, the thermal conduc tivity of the material can be calculated. Hot plate appa ratus accommodating specimens on the order of one foot square and an inch or more thick is common. The appa ratus at the National Bureau of Standards takes specimens 8-in- square, while (dates as large as 3-ft square have been used- The thermal conductivity of cylindrical or pipe in sulation (Chapter 27) is determined in a similar manner except that an equivalent thickness must be calculated to account for the cylindrical shape." Recently there has been considerable development of. transient state conductivity apparatus utilizing a slender Instruments and Measurements 635 probe.'*' '*'*" These instruments are commercially avail able and have tbe advantages of rapidity and requiring a email test specimen. While useful as research and develop ment tools, the probe has not been generally accepted as have the guarded hot plate and pipe insulation apparatus. In the case of some small equipment, the expense of the direct test is not considered justifiable, and the indirect test is relied upon with an arbitrary radiation and unac counted for factor" Hue-Gas Analysis - Wall Conductances The thermal conductances (C values) of many walls can be satisfactorily estimated from the conductivities of their components and their dimensions, but some walls are com plicated by the inclusion of metal, for instance, and tests for conductance are required. The apparatus is required to accommodate large specimens representing actual construc tion. The guarded hot box apparatus was developed for this purpose. Test specimens for the apparatus at the National Bureau of Standards are 5 ft long and 8 ft high, while others require different sizes, some larger, others smaller. The guarded hot box is described in the ASTM Standard Test Code for Btnlt-up Sections C-236-54T." The apparatus consists essentially of three boxes: a cold box, cooled by a refrigerating machine; a hot box, heated electrically; and a metering box also heated electrically. Each box has an open ride to be placed against the specimen. The cold box is damped against one ride of the specimen, and the hot box against the other. The hot box encloses the metering box and is kept at the same temperature to minimize heat exchanges to or from the metering box, except through the specimen. The electric energy necessary to heat the meter ing box is measured, converted to Btu per hour, and di vided by the area and the temperature difference through the wall, from surface to surface, to yield the conductance of the wall. The transmittance or U value of the wall is then computed by means of the surface coefficients from Chapter 9. * A heat-flow meter is sometimes useful for measuring steady heat flow through a wall or other building mem ber."- " m In essence, this meter consists of a plate or slab of material of known thermal resistance having attached thermocouples on both sides. For use, the device is pressed against or cemented to the wall to be tested. At steady slate, the temperature difference through the slab, measured with the thermocouples, with the known thermal resistance of the slab, indicates tire heat flow through the slab and hence, through the wall covered by it. For best results, such meters are calibrated by means of a guarded hot plate or other suitable apparatus. The chief precaution is to assure that the heat flow is steady at the time of measurement. COMBUSTION ANALYSIS There are two approaches to the problem of measuring the capacities of fuel-burning devices, such as boilers and furnaces. The direct or calorimetric test consists in measur ing the change in enthalpy or heat content of the fluid, air' or water, heated by the device and multiplying by the flow rate in pounds per hour to arrive at the capacity in Btu per hour.4* The indirect test consists in determining the heat lost in the flue gases and deducting it from the heat evolved by combustion of the fuel." A heat balance con sists in the simultaneous application of both tests to the same device. The indirect test almost invariably indicates the greater capacity, and the difference is credited to radiation from the boiler or furnace casing and unaccounted for loss. - The Orsat apparatus is commonly used for analyzing flue gases. In its ordinary form, it consists of three pipettes and a means for isolating a sample of flue gas in a graduate. After measuring, the sample is expelled from the graduate into the first pipette where the carbon dioxide is extracted by potassium hydroxide. The sample is then remeasured and successively passed into the second and third pipettes, where the oxygen and the carbon monoxide are respectively extracted by potassium pyrogallate and cuprous chloride. For field testing and burner adjustment, simpler portable . devices are available for carbon dioxide determination only. From curves, based on typical hydrogen content of several common fuels, efficiencies may be estimated from the car bon dioxide value obtained. More elaborate laboratory equipment is sometimes provided for precise determination of carbon monoxide content by burning the carbon mon oxide-to carbon dioxide in presence of a catalyst."*" In large plants, carbon dioxide recorders are used to obtain a continuous indication of the plant's efficiency SMOKE DENSITY MEASUREMENTS Ringelmann charts are widely used for evaluating tbe density of smoke discharged from chimneys or stacks, and smoke ordinances are based on them in some cities. Each chart is composed of a series of crossed black lines on white paper which, at a distance of about 50 ft, is visually com pared with the smoke under observation. Four charts are used with different degrees of blackness as shown in Table 1. The smoke density is specified by Ringelmann numbers from l to 4. Table 1.... Ringelmann Smoke Chart Spacing* Nvmbar of Card Tlucfciimi of Linos, am Dntdaet hi Cfeor Between Line*, bb 1 1.0 9.0 2 2.3 7.7 3 3.7 6.3 5-5 4.5 The photoelectric cell is used in some apparatus devel oped for smoke density recording in large plants. Tbe same device is included in the testing equipment for domestic oil burners described in National Bureau of Standards, Commer cial Standard CS75-42." Under Laboratory Tests this publi cation contains the following section: "Smoke Determina tion.--After combustion has reached equilibrium, the amount of smoke in the flue gases, when viewed lengthwise through-4 feet of.the smoke pipe in accordance with the Underwriters? Laboratories, Inc., Standard for Domestic Oil Burners (Subject 296), March 1934 and subsequent re visions, shall not reduce the output of a standard photo electric cell from 9 microamperes, with a clear smoke pipe, to less than 8 microamperes." The Commercial Standard also requires that during a test after installation, tbe burner shall operate without visible smoke at the chimney top. A method of evaluating smoke produced by pot-type oil 636 CHAPTER 44 1959 Guide burners was developed for the Institute of Cooking and Heating Appliance Manufacturers by R. N. St. John. A gifl-gg rod is interposed between a light source and a photo sensitive cell, both before and after being exposed to the due gases from a heating device. The diminution, of the light transmitted by the rod, due to the deposit of soot on its surface, causes a reduction in the cell mf which is taken as an index of the concentration of smoke in the flue gases. A description of the method is contained in National Bureau of Standards Commercial Standard CS104-46. DETERMINATION OF AIR CONTAMINANTS Two measures of air dustiness are in use: particles per unit volume of air, and weight per unit volume of air. A comparative method consists in drawing known samples of air through a known area of filter cloth or paper, and comparing the density of the resulting spots with black ness charts or with spots from-other sources. For counting, particles are captured in a device such as the Smith-Creenburg impinger, the Owens jet dust counter, or in an electrostatic or a thermal precipitation device de signed for the purpose." Counting is done with a micro scope, and the method yields important results when the nature or constituents of the dust are of interest. ' For a weight determination, a known volume of air is drawn through a porous crucible or thimble, and the weight - gained by the thimhl* during the operation is the weight of the dust captured from the sir sample." For precise work, the thimble must be dried in a desiccating chamber before weighing each time. . At the National Bureau of Standards a test method was developed for interested Government agencies, under which measured samples of the uncleaned air and of the air cleaned by a device under test, are passed through filter papers." The ratio of the flow rates through the two filter papers is adjusted during successive tests, until the resulting dust spots approach equality in density as shown by a photom eter. The ratio of the Sow rates is then indicative of the effectiveness of the cleaner in arresting dust. A statement of an air cleaner's efficiency by any test method, is meaning less unless the test dust is specified. Other instruments for determining gaseous and particulate air contaminants are described in industrial hygiene literature."* "* SOUND AND VIBRATION MEASUREMENTS71-7*- "74- 7` The measurement, analysis, and ultimate control of noise in air-conditioning systems is becoming increasingly impor tant. The sound-level meter is the basic instrument used in acoustic measurements. While a crystal-type microphone is usually supplied with the meter, dynamic and condenser- type microphones can also be used. The dynamic type is employed when the microphone and sound-level meter are separated by a long cable. The condenser microphone is stable and has a flat response. Crystal microphones are stable and sensitive, but require a temperature correction when connected to the sound-level meter through a long cable. - In the refined art of acoustics, the overall or total sound level is of little value. Loudness and annoyance as inter preted by the ear are a function of frequency as well as sound level. The effective rating and control of noise must, therefore, involve the measurement of frequency distribu tion. The octave-band analyzer, which divides the noise spectrum into eight frequency bands! is most commonly used in conjunction with the sound-level meter. A number of the criteria that have been developed for environmental noise levels are based on octave bands. Narrow-band filters are also available, and impact noise analyzers can be used to measure transient noise levels such as those produced by drop-forge hammers. Electronic instruments are available for measuring the frequency, amplitude, and acceleration of a vibrating mass. Vibration meters are usually portable, self-contained, and direct reading. . REFERENCES 1For a comprehensive treatment of temperature measure ment the reader is referred to Temperature, Its Measurement and Control in Science and Industry (symposium of American Institute of Physics, published by Reinhold Publishing Corp., New York). *H. D. Baker, E. A. Ryder, and N. H. Baker: Temperature Measurement in Engineering (John Wiley and Sons, New York). . Temperature measurement (ASMS Power Test Code, Part 3). 4G. V. Pannelee and R. G. Huebscher: ASHVE Research Report No. 1292--The shielding of thermocouples from the effects of radiation (ASHVE Transactions, Vol. 52, 1946, p. 183). 4P. Nicholis and W. E. Rice: Errors in the measurement of the temperature of flue gases (ASHVE Transactions, Vol. 35, 1929, p. 473). A. C. Willard, A. P. Kratz, and V. S. Day: Investigation of Warm Air Furnaces and Heating Systems (Illinois Engineering Experiment Station Bulletin No. 120). ' *P. Nicholis: Measuring heat Transmission in building struc tures and a heat transmission meter (ASHVE Transactions, Vol. 30, 1924, p. 94). *W. B. Kirk and G. J. Pac&novsky: Parallel-connected thermocouples for the testing of gas appliances (Gas, Septem ber 1939, p. 51). American Standard for Indicating Pressure and Vacuum Gages, Round Dial Type, with Elastic Pressure Chamber (American Standards Association, B. 40J--1939). Standard Test Code for Centrifugal and Axial Fans (ASHVE and NAFM, published as NAFM Bulletin No. 110, 1938). * u Fan Engineering (Buffalo Forge Company, Buffalo, New York, 5th ed,, p. 165). ** Illinois Micromanometer (University of Illinois, Engineer- ing Experiment Station Bulletin No. 120, p. 91). a J. E. Emswiler and W. C. Randall: The weathertightness of rolled steel windows (ASHVE Transactions, Vol. 34, 1928, p. 527). *. u Psyckrometnc Tables for Vapor Pressure, Relative Hu midity and Temperatures of the Dew-Point (U. S. Department of Agriculture, Weather Bureau). . u For technical data refer to Fluid Meier Reports (American Society of Mechanical Engineers, Parts 1--1937, 2--1931, and 3 --1933). " National Advisory Committee for Aeronautics Technical Notes No. 546 (November 1935). "F. R. Ingram, E. Dies-Canseco, and L. Silverman: The characteristics of double Pitot tubes (ASHVE Journal Section, Heating, Piping and Air Conditioning, November 1942, p. 708). "H. S. Bean, E. Buckingham, and P. S. Murphy: Discharge coefficients of square edged orifices for measuring the flow of air (Bureau of standards Journal of Research, Vol. 2, 1929, p. 561). " Flow measurement by nozzles and orifice plates (ASME Power Test Codes, 1949, Part 5 (rf Chapter 4). Instruments and Measurements 637 "Pressure measurement (ASME Power Test Code, 1936, Part 2 of Chapter 2). nD. D. Wile: Air flow measurement in the laboratory (Re frigerating Engineering, June 1947, p. 515). " G. L. Tuve, G. B. Priester, and D. K. Wright, Jr.: ASHVE Research Repost No. 1204--Entrainment and jet-pump action of air streams (ASHVE Transactions, Vol. 48, 1942, p. 241). "A. P. Krats, A. E. Hershey, and R. B. Engdahl: ASHVE Research Report No. 1165--Development of instruments for the study of air distribution in rooms (ASHVE Transactions, Vol. 46, 1940, p. 351). "D. D. Wile: Development of testing apparatus for thermo stats (ASHVE Transactions, Vol. 42, 1936, p. 349). "J. F. Kemp: Stable hot-wire anemometer for low speeds (ASHAE Journal Section, Heating, Piping and Air Condition ing, October 1957, p. 137). . "C. P. Yaglou: The heated thermometer anemometer (Jour nal of Industrial Hygiene and Toxicology, Vol. 20, October 1938). "H. B. Nottage: A simple heated-thermocouple anemometer (ASHVE Transactions, Vol. 56, 1950, p. 431). "L. E. Davies: ASHVE Research Reports Nos. 857, 911, and 966--Measurement of the flow of air through registers and grilles (ASHVE Transactions, Vol. 36, 1930, p. 201; Vol. 37, 1931; p. 619; and Vol. 39, 1933, p. 373).. "G. L. Tuve and D. K. Wright, Jr.: ASHVE Research Re port No. 1162--Air flow measurements at intake and discharge openings and grilles (ASHVE Transactions, Vol. 46, 1940, p. 313). "A. M. Greene, Jr. and M. H. Dean: ASHVE Research Report No. 1092--The flow of air through exhaust grilles (ASHVE Transactions, Vol. 44, 1938, p. 387). "G. L. Larson, D. W. Nelson, and R. W. Kubasta: ASHVE Research Report No. 936--Investigation of air outlets in room ventilation (ASHVE T&an&actions, Vol. 38, 1932, p. 463). "D. W. Nelson and D. J. Stewart: ASHVE.Research Re post No. 1076--Air distribution from side wall outlets (ASHVE Transactions, Vol. 44, 1938, p. 77). "G. L. Tuve: Measuring air flow (Heating, Piping and Air Conditioning, December 1941). "G. L. Tuve, D. K. Wright, Jr., and L: J. Siegel: ASHVE Research Report No. 1140--The use of air velocity meters (ASHVE Transactions, Vol. 45, 1939, p. 645). "O. W. Armspach and Margaret Ingels: Temperature, hu midity and air motion effects m ventilation (ASHVE Trans actions, Vol. 28, 1922, p. 103). "H. B. Nottege, J. G. Slaby, and W. P. Gojsza: A smokefilament technique for experimental research in room air dis tribution (ASHVE Transactions, Vol. 58, 1952, p. 399). "J. B. Dick: Measurement of.ventilation using tracer gas technique (ASHVE Journal Section, Heating, Piping and Air Conditioning, May 1950, p. 131). "C. W. Coblentz and P. R. Achenbach: ARWAF. Research Repost No. 1616--Design *nd performance of a portable infil tration meter (ASHAE Transactions, Vol. 63, 1957, p. 477). "W. H. Carrier: The temperature of evaporation (ASHVE Transactions, Vol. 24, 1918, p. 25). "H. B. Nottage: ASHVE Research Report No. 1401--A proposed psychrometric chart (ASHVE Transactions, Vol. 56, 1950, p. 411). u W. H. Carrier and C. O' Mackey: A review of existing psychrometric data in relation to practical engineering prob lems (ASME Transactions, January 1937, p. 33). Discussion (ASME Transactions, August 1937, p. 528). . "Arnold Wexler: Divided Flow Low Temperature, Humid ity Test Apparatus (National Bureau of Standards Research Paper No. 1894). "H. A. Daynes: Gas Analysis by Measurement of Thermal Conductivity (Cambridge Press, New York, 1933). . "H. M. Vernon: The measurement, in relation to human comfort, of the radiation produced by various heating systems (Institution Heating Ventilating Engineers Proceedings, VoL 31, p. 160). .. "T. Bedford and C. G. Warner: The globe thermometer in studies of heating and ventilatiog (Institution Heating Venti lating Engineers Journal, Vol. 2, 1935, p. 544). "D. J. Sutton and P. E. McNall, Jr.: A* two-epbere radiom eter (ASHVE Transactions, Vol. 60, 1954, p. 297). "A. C. Willard, A. P. Kratz, and M. K. Fahnestock: The application of the eupatheoscope for measuring the perform ance of direct radiation and convection in terms of equivalent temperature (ASHVE Transactions, Vol. 39, 1933, p. 303). "C. P. Yaglou: Physical procedures in air analysis--Instru ments and methods for recording thermal factors: affecting hu man comfort (American Journal Public Health Supplement, VoL 26, March 1936, p. 76). C. P. Yaglou, A. P. Kratz, and C.-E. A. Winslow: Instruments and methods for recording thermal factors affecting human comfort, I--Report of subcommittee on physical procedures in air analysis (American Journal Pub lic Health Supplement, Vol. 27, March 1937, p. 84). "C.-E. A. Winslow and Leonard Greenburg: The thermo- integrator--a new instrument for the observation of thermal interchanges (ASHVE Transactions, Vol. 41, 1935, p. 149). " Standard Method of Test for Thermal Conductivity of Materials by Means of the Guarded Hot Plate (adopted July 1942 by ASHVE, ASTM Designation C 177-45). " Tentative Method of Test for Thermal Conductivity of Pipe Insulation (ASTM Designation C 335-54T). "D. D'Eugtachio and R. E. Schreiner: A study of transient heat method for measuring. thermal conductivity (ASHVE Transactions, Vol. 58, 1952, p. 331). "F. C. Hooper and F. R. Lepper: Transient heat flow ap paratus for the determination of thermal conductivity (ASHVE Transactions, Vol. 56, 1950, p. 309). ` "F. C. Hooper and S. C. Chang: Development of thermal conductivity probe (ASHVE Transactions, Vol. 59, 1953, p. 463). "C. P. Lents: A transient heat flow method of determining thermal conductivity: Application to insulating materials (Ca nadian Journal of Technology, Vol. 30, June 1952, p. 153). " Tentative Method of Test for Thermal Conductance and Transmittance of Built-up Sections by Means of Guarded Hot Box (American Society for Testing Materials, ASTM-C-23649T). "P. Nicholis: ASHVE Research Report No. 685--Measur ing heat transmission in building structures and a heat trans mission meter (ASHVE Transactions, VoL 30, 1924, p. 65). "R. G. Huebscher, L. F. Schutmm, and G. V. Parmelee: A low-inertia low-resistance heat flow meter (ASHVE Transac tions, Vol. 58, 1952, p. 275). "J. T. Gier and R. V. Dunkle: Using the heat flow meter to . study heat transfer (Refrigerating Engineering, Vol. 62, October 1954, p. 63). m I ~ B ~ R Testing and Rating Codes for Low Pressure Heating Boilers (Institute of Boiler and Radiator Manufac turers, 1947). .- ** Commercial Standard for Warm Air Furnaces Equipped with Vaporising Pot-type Oil Burners (National Bureau of Standards, CS. 104-26). "Martin Shepherd.: Rapid determination of small amounts of carbon monoxide (Industrial and Engineering Chemistry, . Analytical Edition, 19, 77, 1947). - "Martin Shepherd: Determination of small amounts of carbon monoxide in air by various reference methods (National Bureau of Standards Journal of Research 38, 351, 1947, R. P. 1777). " Commercial Standard for Mechanical Draft Oil Burners Designed for Domestic Installations (National Bureau of Standards, CB. 75-42). " Philip Drinker and Theodore Hatch: Industrial Dusts (McGraw-Hill Book Co., New York). 638 CHAPTER 44 1959 Guide S. R. Lewis: Testing and rating of air cleaning devices used for general ventilation work (ASHVE Transactions, Vol. 39, 1933, p. 277). "R. 8. Dill: A test method for air filters (ASHVE TeansACnoifs, VoL 44, 1938, p. 379). * M. B. Jacobs: Analytical Chemistry of Industrial Poisons, Hazards arid Solvents (Interacience Publishers Inc, Mew Ycnk, 1941). J. J. Bloomfield and J. M. Dalla Valle: The Determina tion and Control of Industrial Dust ((/. S. Public Health Bulle tin No. 217, 1935). "F. A. Patty: Sampling and Analysis of Atmospheric Con taminants (Industrial Hygiene and Toxicology, VoL 1, Inter science Publishers Inc, New York, 1948). "E. E. Gross, Jr.: Noise measuring and sound-control (5ejrigeratmg Engineering, Vol. 66, May 1957, p. 49). SA. P. Peterson and L. L. Beranek: Handbook of Noise Control (General Radio Co, Cambridge, Massachusetts, 1954). n L. L. Beranek: Acoustics (McGraw-Hill Book Co, New York). " H. P. Olson: Elements of Acoustical Engineering (D. Van Nostrand Co, New York). "American Tentative Standards for Sound Level Meters for Measurement of Noise and Other Sounds (American Stand ards Association, Z24.3-1944). CHAPTER 45 MOTORS AND MOTOR CONTROLS Fundamentals of Motor Selection; Alternating-Current Motors, Types and Control Equipment; Motor Rating; Functions of Motor Control Equipment; Glossary of Motor Terms, Enclosures, Speed Classification and Mounting THE electric motor, available in many different types 1. Mechanical Arrangement. Arrangement of the driven suitable for various services, is now the most widely machine usually determines whether a horizontal or vertical used form of motive power. The equipment for starting, conmotor is needed. Horizontal motors are more generally avail trolling, and protecting these motors varies with the type able and less expensive; most grease-lubricated ball-bearing and with the functions it is desired to attain. Motors are motors will operate in either position. Fractional-horsepower divided into two general classifications, alternating-current waste-packed sleeve-bearing motors are satisfactory for short or direct-current, depending on the power source to be used. -periods of vertical operation where no thrust is involved. FUNDAMENTALS OF MOTOR SRECTION If shaft is tilted for momentary operation, special con struction of bearing housings wiU be required for oil-ring- The following characteristics of the power supply should lubricated sleeve-bearing motors, to avoid loss of lubricant. be determined: (1) whether current is alternating or direct, In case of long periods of tilted operation, bearings suitable (2) voltage, (3) alternating-current phase, (4) alternating- for end thrust may be necessary. Ball-bearing motors with current frequency, (5) voltage regulation, (6) continuity of power. grease lubrication are suitable for tilted operation. Most motors are suitable for mounting with base above a 1. A-C vs. D-C Systems. For most applications, a-c supply horizontal shaft or to one side of the shaft, provided the is satisfactory since suitable performance can.usually be ob end shields are rearranged. If, during operation, the angle of tained with a-c motors and control. Where special charac the motor (with regard to the horizontal 6haft) changes teristics, such as an extra wide speed range and severe ac more than 10 or 12 deg, a ball-bearing motor will usually be celerating or reversing duty are involved, conversion by means of motor generator sets, by rectifiers, or in special, required. Sleeve-bearing motors are also applicable within the angle given if modified oil gages are provided. cases by converters, may be justified. ..... On portable machines, motors of greater compactness and 2. Voltage. Standard conditions of voltage and frequency are the values listed on the namp plate of the motor. Reason able horsepower design limits are given in Table 1. Power lines are often given voltage ratings known as nominal system . voltages which are numerically slightly different from the standardized motor voltages. 3. Phases. Three-phase power supply is most desirable, but only single-phase is offered for-most residential and rural districts. 4- Frequency. Sixty-cycle systems predominate in the United States. In foreign countries, 50-cycle systems are com mon and nominal system voltages are frequently different. less weight than standard may be required, and special bear ing construction may be needed, except for ball-bearing mo tors. Direct connection should always be considered where machine speed coincides with available motor speed. Maintenance, efficiency, power factor, space, and initial cost, will determine the choice between direct connection and other methods, such as belt, chain, or gear drive. When direct connection is possible (where parts of the driven ma chine, such as shaft or bearings, are common with the motor structure) a built-in construction may be advantageous. Beit Drive. Diameters and widths of pulleys or sheaves and center distances are factors in determining motor-bearing pressures and shaft deflection. Flat belts should not run at 5. Voltage Regulation. The voltage regulation of the power greater speeds than about 5000 1pm. Application of flat supply should be known in order to select motors which will belting to vertical-shaft motors is difficult. - deliver sufficient torque even with the probable drop in Chain Drive. The chain manufacturer should be consulted voltage, to start and carry the load. All induction motor so that the best drive on a basis of quietness and economy of torques and synchronous-motor starting and pull-in torques operation may be selected. vary as the square of the voltage. Gear Drive. Compactness and arrangement of drive often 6. Continuity of Power. Dips in voltage from switching or indicate gear motors, which are obtainable in a variety of other line disturbances may necessitate time-delay under mechanical constructions with speed ratios of 3 to 1 upwards, voltage protection, and, in case of synchronous-motors, high and are generally limited to about 75 hp maiimnm Where torque designs and resynehromzing control. Sustained low the pinion of ordinary spur gearing is mounted on- the motor voltage may necessitate higher torque motors. shaft, two-bearing motors are limited in. horsepower ratings. The following characteristics of the driven machine should Maximum pitch-line speed with steel pininna is about 1400 be determined: (1) mechanical arrangement including po fpm. sition of motor and shaft, portability desired, drive connec The selection of the motor part of a gear motor is the tion, and space limitations; (2) speed range desired; (3) as for a conventional motor. horsepower requirement; (4) torque; (5) inertia; and (6) frequency of starting. Space limitations may affect the choice of motor and re quire (a) built-in construction; (b) a gear motor; (e) forced' 639 640 CHAPTER 45 1959 Guide Table 1.... Reasonable Horsepower Design Limits for Standard Motor Voltages Sowar Supply Standard Molar Voltage Suggested Minimvm Horaepowar Suggested MoJtfowsi' Horsepower Alternating 1-phase 115 230 Alternating 3-phase 110 -220 440-550 2300 4000 4600 6600 None None None None 1 50 100 250 400 .I 15 15 200 1000 6000 7500 8000 None ventilation using an external blower; or (d) a small frame with Class B or H insulation permitting higher temperature rise. . 2. Speed Range. Where more than one speed or a range of speeds is required, one of the motor types listed in Table 2 may be applicable, depending upon the power supply and the speed range required. 3. Horsepower Requirement. The horsepower required by the driven machine determines the motor rating. Where the load varies with time, a horsepower vs. time curve will permit determination of the peak horsepower required. The calcu lation of the root-mean-square (rms) horsepower indicates Table 2 .... Speed Ranges for Various Types of Motors Power Seppfy . Type Speed Range SinglePhase a-c * Brush-shifting repulsion motor a Capacitor motor with tapped winding Multi-speed capacitor motor 3:1 2:1 2 or 3 fixed speeds Polyphase a-e Multi-speed squirrel-cage Wound-rotor motor * 2-speed wound-rotor motor Brush-shifting shunt motor * Brush-shifting series motor Squirrel-cage motors with variable frequency supply Motor-Generator Set--D-C Drive Motor Rectifiers--D-C Drive Motor 2, 3, or' 4 fixed speeds 2:1 4:1 20:1 3:1 Very wide range Very wide range Very wide range Shunt-wound standard con 2:1 in some cases stant-speed motor with field control d-c D-C motor with armature Wide control Adjustable-speed motor From 3:1 to 6:1 Shunt motor with adj ustable- Very wide voltage supply * Speed regulation reUlivelj wide. Unsuitable for some loads. the proper motor rating from a heating standpoint. In ease of extremely large variations in load, or where shutdown, ac celerating, or decelerating periods constitute a large portion of the cycle, the rms horsepower may not give a true indica tion of the equivalent continuous load. The motor manu facturer should, therefore, be consulted. Where the load is maintained at a constant value for an extended period (varying from 15 min to 2 hr, depending on the size), the horsepower rating required will usually not be less than this constant value, regardless of other parts of the cycle. '' If the driven machine is to operate at more than one speed, the horsepower required at each speed must be determined. 4. Torque. The torque required to operate the driven ma chine at-every moment between initial breakaway and final shutdown is important in determining the type of motor. A torque-speed curve is desirable and sometimes essential. The starting torque or breakaway torque required by the driven machine may be as low as 10 percent, as in the case of medium-sized centrifugal pumps, or as high as 225 to 250 percent of full-load torque, as in the case of a loaded re-' ciprocating two-cylinder compressor. The breakaway.torque may vary greatly at different times because of frequency of start, temperature changes, type and amount of lubricant, etc. The motor torque available at the shaft must be well above the torque required by the driven machine, taking into consideration these variables as'well as the possibility of low voltage and the type of starter used. The torque required after breakaway for acceleration to full speed varies with different driven machines, remaining at a rather high value throughout acceleration for such ma chines as loaded compressors and plunger pumps. The torque delivered by the motor must at all points, up to full speed, be in excess of the torque required by the driven machine. The greater this excess torque, the faster will be the accelera tion. The approximate time required for acceleration from rest to full speed is: Time in seconds * (rpm) x WR* (T X 308) (1) where (rpm) = full-load speed in revolutions per minute. T ** average torque available for acceleration, foot pound. WRf inertia of rotating parts, pound-foot square. If the time to accelerate on full voltage is greater than about 20 sec, special motors or starters may be required to avoid overheating. - 5. Inertia of Driven Machine. The inertia or flywheel ef- feet Wf* of the rotating parte of the driven machine affects the accelerating time and, therefore, the heating of motors and control, particularly where reversing duty or frequent starting is involved. . ' Where synchronous motors are applied, the WR? must be known, since the pull-in torque required of this motor varies approximately as the square root of the total WRM of motor and load. The WJ2* of a rotating member of the driven machine which operates at a speed different from that of the motor may be converted to an equivalent value at the motor shaft by multiplying by [(rpm of rotating member) -5- (rpm of motor)}1 (2) 6. Frequency of Starting. The frequency of starting the driven machine affects the motor and control by increasing Motors and Motor Controls 641 their beating, particularly where accelerating time is pro longed by high WR* and high load torques. In general, driven machines starting more than 4 to 6 times per hour may re - quire special motors and control. - ALTERNATING-CURRENT MOTORS Alternating-current motors are divided into two main classifications: polyphase and single-phase (see Table 3), ac cording to the type of power supply. They are further sub divided by type of motor winding. When polyphase power is available it is usually found more economical to apply polyphase motors in preference to single-phase motors. A typical 5 hp, 1200 rpm capacitorstart induction-run single-phase motor, for instance, will cost approximately twice as much as the corresponding three-, phase Design B squirrel-cage motor. In addition, the poly phase motor has the advantage of higher efficiency. . Polyphase Motors Fig. 1 .... Speed Torque Characteristics of Squirrel-Cage Motors The three types of polyphase motors are: squirrel-cage induction motors, wound-rotor induction motors, and syn chronous motors. Squirrel-cage motors are specified by NEMA standards providing a variety of speed and torque characteristics. Design A motors provide normal starting torque at starting . current in excess of Design B motors, and are suitable for constant speed application to equipment such as fans and blowers. Design B motorsprovide normal starting torque with NEMA starting current values shown in Table 4, which are acceptable by many power companies for full voltage starting. They are used for the same type of application as Design A. Design C motors provide high storting torque with starting current same as Design B, and arc used on compressors started without unloaders, and on reciprocating pumps. Design D motors have high slip* and are used with flywheels for widely pulsating loads on equipment such as reciprocating compresors and pumps where other motors would draw high peak currents. Design F motors have low starting current and low torques. They are used on power systems of limited capacity. Careful application must be made since the low breakdown torque provides only limited safety margin for overload or low voltage conditions. A drop in voltage, for instance, could cause the motor to stall. Figs. 1 and 2 illustrate the characteristics of squirrel-cage motors. The motor operates under load from near syn chronous speed at light load toatiout 95 percent synchronous speed at full load. Overloads decrease the speed further until the maximum torque point is reached. If the load torque exceeds this point the motor will stall. The motor torque varies as the square of the voltage. If the voltage drops 10 percent, the motor torque will be only 81 percent of rated value. Both power factor and efficiency are improved if the motor is operating as near rated load as possible. In addition, as shown in Fig. 2, power factor and efficiency are better for higher speed motors. Hermetically-enclosed polyphase a-c motors are now quite generally used with large centrifugal compressors. The motors are built into the compressors and are cooled by circulation of refrigerant through the motor windings or by circulation of condenser cooling water through the motor housing. In either case, the cooling is excellent and the motor can deliver more power than if it were air-cooled. Wound-rotor motors are used for applications requiring high starting torque at low starting current, because a wound- *Btfcr Co Gloour at cad at e&apter. rotor motor with its controller and resistance can develop full load torque when storting with about full load current. For comparison, a squirrel-cage motor would require from 3 to 5 times as much current to develop full load torque at starting. The wound-rotor motor is also used for varying speed service to drive fans, blowers, and other continuous duty apparatus. The addition of resistance to the secondary winding of the wound-rotor motor changes the speed torque characteristics. The motor speed, with the resistance added, is dependent on load, and consequently, the motor has very poor speed regula tion when secondary resistance is added to reduce the speed Squirrel-Cage Induction Motors 642 CHAPTER 45 1959 Guide Type Table 3 .... Classification of Motors Speed Gmodtritikt FvO Voltage Slutlaig Torque Starting HP Kongo See Footnote* (e) to M Constant Speed Drives Polyphase a-c Single-phase a-e .\ Squirrel-cage general Constant purpose Design A Normal 1-2.5 High 6-8 All times' times (a) Fans and (c) centrifugal pumps and centrifugal com pressors Squirrel-cage Design B Constant Normal 1-2.5 Normal 5- Medium times' 6 times Small (a) Fans and centrifugal * pumps and centrifu gal compressors Squirrel-cage Design C Constant High 2-2.5 Normal 5- Medium times' 6 times Small (5) Reciprocating pumps () and compressors started loaded Squirrel-cage Design F Constant Low 1.25 Low 4 times Medium Large Fans, centrifugal pumps. and compressors Wound rotor Constant or High 1-2.5 Low 1-3 All variable times times (with secondary control) (a) Hoists (5) reciprocating pumps and compressors (c) and frequent (e) or hard start Synchronous high speed Exactly con- Normal 0.75- Normal 5- Medium stant 1.75 times 7 times Large (a) Fans and centrifugal pumps and centrifu gal compressors Synchronous low speed Exactly con- Low 0.3-0.4 Low 3-4 Medium stant times times Large (a) Reciprocating compressors starting un- . loaded Two value capacitor Constant . High Normal Small (6) Pumps and compres8018 Permanent split capaci- Constant tor Capacitor start Constant Repulsion Induction Constant Low Moderate High Normal Normal Normal Fractional (o) Fans, Blowers . Small Frac tional Medium Small (a) Fans and pumps (a) Fans (5) pumps and compres- sore Split phase Constant anc Normal adj ustable Normal Fractional (a) Fans (5) pumps and compres- sors (d) fans--direct to values below 50 percent. Fig. 3 illustrates the character istics of wound-rotor motors. Synchronous motors are used for continuous duty applica tions at constant speed where efficiency and power factor are important. Another advantage of these motors is that of lower initial cost in large sizes and for low speeds when com pared with squirrel-cage type motors. The outstanding advantage of the synchronous motor is that its power factor can be changed to compensate for the low power factor of other drives in the same location. lagging power factor is an inherent characteristic of all induction apparatus, such as induction motors and neon signs. Unless synchronous motors or capacitors are installed, the plant power factor may be comparatively low. This does not Motors and Motor Controls 643 Table 3 .... Classification) of Motors (Continued) Type fufl Voltage Owrodtnilki Starting Torque Starting Cerrent HP Kongo Adjustable Speed Drive* Application See Footnote* (a) to () Snuirrel-cave high sliD. Variable Transformer adjust ment Normal Normal Medium Small (a) Fans Polyphase a-e Squirrel-cage separate Constant winding or regrouped multi- poles speed Normal or Normal or All high low (a) Fans (5) pumps and (e) compressors Wound rotor Variable High Low All (with secondary control) ' (a) Fans (5) centrifugal pumps and compressors Repulsion Variable High* Normal Low and Fractional (a) Fans, centrifugal pumps (5) compressors Single-phase a-c Capacitor low torque Variable two Low. tapped winding speed Capacitor low torque Variable transformer adjust ment Low Normal Fractional (d) Fans, direct Low Fractional (d) Fans &Dlit Dhase resrouDed Constant poles Normal Normal Fractional (d) Fans o. Drives bvin* im*hm or low startiBg torque cad inerti* WE* mob ac fane cod eeatrilugal pomp* or recipmeti&g pumps and eompnaaore started unloaded. 6. Drive* bovine high ctaxtiac torque*, *och as reoprocatiiig pump* and eomprenen started loaded. e. RimiW to (a) except wtere frequent or hexdstartinc (large VS1) require* e taxiing and accelerating torque. d. Fan direct connected. . Stoker /. Torque depend* on hp rating and ipced. See NEMA fifaedard MGM.10 os Motor* and Gencntor*. Table A .... Locked-rotor Current of Three-phase, 60-cyde Motors at 220 Volts b HP Design 8, C, and O Ampere* Design f Amperes HP Design 8, C, end D Amperes 1 or 1au> 1H 2 3 5 24* 35 45 60 90 .30 40 50 60 75 435 580 725 870 1085 270 360 450 540 675 jm 10 15 20 25 120 150 220 290 365 100 1450 125 1815 150 2170 200 2900 900 1125 1350 1800 * The locked-rotor cunexit of three-phase, O-eycle, constant-speed, Induction motes*, tne*ured with* rated voltage and frequency ienpremed and with rotor locked, shall not *i:*jul the tabulated value*. b locked-rotor current at other voltage* ifaall be inversely proportional tothe voltage. . * Far 1 hp or lees the value t* given per hp. of Wound-rotor Motors 644 CHAPTER 45 1959 Guide ' necessarily mean that corrective equipment must always be installed, but in most cases it is desirable to determine what advantages may be gained by improving the power factor. With purchased power, if the rates include a clause embody ing a penalty for low power factor, or a bonus for high power factor, the saving in power costs may often make a very good return on the investment required for the corrective equip ment. ' Synchronous motors are used to drive fans, blowers, pumps, compressors, and other applications. Compressor applications having a high peak torque require the use of flywheels to smooth out power peaks, and should always be referred to the electrical manufacturer for recommendations. Synchronous motors are provided with built-in damper -windings on the rotor and operate during the starting period similarly to squirrel-cage motors. After the motor is nearly up to speed, field excitation is applied and the motor draws into step at synchronous speed. After excitation is applied, the motor runs at exactly constant speed and will remain at this' speed until a load approaching the pull-out load is reached, whereupon the motor pulls out of synchronism and stops. ' In applying synchronous motors, consideration must be given to the torque the motor can develop on pull-in, that is, at the instant when field excitation is applied. Table 5 shows typical application requirements of synchronous motor drives, listing starting, pull-in, and pull-out torques. . Multi-Speed motors provide flexibility in many types of drives. Synchronous motors can be furnished.only with a 2 to 1 ratio in speed, single-winding.' Squirrel-cage induction mo tors may be 2-, 3-, or 4-speed. Two-speed induction motors are usually of single-winding type, having a 2 to 1 speed ratio such as 600 rpm and 1200 rpm, or may be double winding. Three-speed induction motors are always twowinding, and four-speed motors are usually two-winding with a 2 to 1 8peed ratio in each winding. Motors can be provided in constant torque, varying torque, or constant horsepower ratings. The constant horsepower type of motor is consider ably larger than the constant torque motor, due to the fact that the same horsepower must be developed at either reduced speed or high speed. In selecting two-speed motors for fan, pump, blower, or compressor applications, it is usually found that two-winding motors are more expensive than the single-winding type. The control cost for two-speed, two-winding motors, however, is more economical, and therefore the combined price of both motor and control for the two-winding motor is only slightly higher. Because of the improved performance of the twowinding motors, and because of the factor of safety provided by two independent windings, the increased cost is frequently worth the difference. Single-phase Motors Single-phase induction motors have auxiliary windings or devices for starting, and are classified by the method used. Capacitor-start motors develop high starting torque in fractional horsepower ratings, and moderate starring torque in larger ratings. They are used for constant speed drive such as fans, blowers, and centrifugal pumps. During the starting period, a winding with a capacitor in series is connected to the motor circuit and when the motor comes up to speed, a centrifugal switch cuts the capacitor and second winding out of the circuit. Two-value-capadtor motors develop high starring torque Table 5 .... Typical Application Requirements of Synchronous Motor Drives Showing Starting, Pull-In, and Pull-Out Torques Application Method of CaamdMf Motor to Load Starting Conditions Starting Torques Pud-fa Pud-Out Fans Exhaust and venti Coupled or belted lating Usually loaded 50 60-125 150 WR* of fan must be considered Blowers Cycloidal positive Coupled or engine Unloaded type Blowing eogines re Engine-type ciprocating Unloaded 40-60 40-60 40 40-60 150 Two-speed motors sometimes used 150 Turbo high speed Direct connected or Unloaded (in 30 50 150 WR* of blower must step up gear take closed) be considered Air Engine-type Unloaded 40 30 160 Flywheel effect im portant Compressors Ammonia and am monia booster ` High speed--belted Low speed--engine- type occasionally coupled Unloaded bypass) (by Freon High speed--belted Unloaded (by Low speed--engine bypass) Gas reciprocating ' High speed--belted - Unloaded (by Low speed--engine bypass) 40 45 40 30 .50 30 150 Flywheel effect im portant 150 Flywheel effect im portant 150 Flywheel effect im portant Motors and Motor Controls employing a starting capacitor and a running capacitor. The starting capacitor gives high starring ability, but is suited for short time operation only, and is cut out for the running condition by a centrifugal switch. The running capacitor gives high efficiency- at full speed. These motors are used on compressors, reciprocating, pumps, and similar equipment which may start under heavy load. Permanent-split-capacitor motors have low starting torque and are ideally suited for Email fan drives. Operation is similar to the capacitor-start motor, except that the capacitor is not cut out when running. Repulsion-start Induction-run motors develop high start ing torque. The motors have a wound rotor connected to a commutator for starting. A centrifugal switch shorts the commutator bars when the motor comes up to speed to ob tain a winding approximately like the squirrel-cage in its function. ' Repulsion-start Induction-run motors are suitable for ap plications, such as industrial compressors, requiring high breakaway torque, and where commutator and brush noise are not factors. Split-phase motors have a high-resistance auxiliary winding which is in the circuit during starring, but is disconnected through the action of a centrifugal switch as the motor comes i up to speed. Under running conditions it operates as a single phase induction motor with one winding in the circuit. These units are available for the small horsepower ratings, and when equipped with a high-slip rotor, may be used for adjust able varying speeds through line-voltage control. The motors are ideally suited for fan duty. Speed-torque characteristics of single-phase motors are shown in Fig. 4. -- Full-voltage starting of single-phase motors is general practice, but since most of these motors are connected to secondary distribution systems located in light-load density 645 areas, power companies check carefully the starting currents in order to prevent objectionable voltage dips. This is par ticularly important for motors started frequently, such as those controlled by pressure or temperature-sensitive devices and applied to refrigerators, stokers, oil burners, and water pumps. The report of a joint committee of AIEC-EEI-NEMA recommended three application rules taking into account the greater annoyances resulting from frequent motor starting during lighting hours against infrequent starting at any time. Table 6 shows typical applications of these rules which are becoming widely accepted for full-voltage starting. Rules 1 and 2 apply to general use. Rule 1 limits the locked-rotor current to 20 amp at 115 volts, and 25 amp at 230 volts when automatically controlled (usually frequently started) motors are used. Rule 2 permits Table 6 .... Recommended Single-Phase Motor Ratings for Full-voltage Starting locfcsd-refar Current* of 25 C HP Rating Amperes Cansref Ute (fatal i A 2) Special Condition* (with Utility Permit- don) (Rule 3) 115 V 230 V 115 V 230 V 115 V 230 V Ho 20 .10 A-M A-M A-M A-M H 20 10 A-M A-M A-M A-M X 20 10 A-M A-M A-M A-M H 23 11.5 A-M A-M A-M A-M X 31 15.5 M A-M A-M A-M H 45 22.5 M A-M A-M A-M X 61 30.5 M A-M A-M 1 70 35 M A-M A-M ix 40 M A-M 2 60 M A-M 3 70 A-M 5 100 A-M A refers to automatically controlled device*. H refers to manually controlled devices. These values of Locked-rotor current are t^>* same as single phase Desicn H motors. hTEMAstandard far Rg. 4 .... Speed Torque Characteristics of " Single-phase Motors twice these values when manually controlled (usually in frequent starting) motors are used. Rule 3 applies to special conditions where larger currents may be allowed above Rules 1 and 2 upon approval of the electric company. Hermetically-enclosed single-phase a-c motors are widely used in appliances such as domestic and commercial refriger ators, room air conditioners, beverage coolers, freezer chests, and water coolers. In such appliances, the motors are sealed inside the compressor, and the gas and oil circulate freely within and around the motor. Centrifugal starring switches are not used on such motors because any arcing in the gas and oil atmosphere would be detrimental, and also because the units are permanently sealed and cannot be serviced or repaired in the field. In place of a centrifugal switch, an external relay-is used to start hermetically-enclosed motors. Hermetically-enclosed motors for refrigeration compressors will, in the future, have the horsepower rating eliminated. The full-load current is to be the operating current in am peres, when the compressor is delivering rated output. The motors for hermetically-enclosed service are usually of the 646 CHAPTER 45 1959 Guide split-phase type or of the capacitor-start (or two-value ca pacitor) type. ' For starting the split-phase type of motor, two methods are generally acceptable. In one method a thermally-operated time delay is used. When the motor is started, a contact which is normally closed applies power to the starting winding. A thermal element which controls these contacts is in series with the motor and carries line current. Due to the current flow through this element, it is heated until, after a definite period of time, it is warmed sufficiently to open the contacts and remove power from the starting winding. The running current then heats the element enough to keep the contacts open. The setting of the time for the starting contacts to open is determined by tests on the system components, i.e., the relay, the motor, and the compressor, and is based on a pre diction of the amount of time delay required to bring the motor up to speed. The second method of starting split-phase motors utilizes a series-cool or current-operated relay. This device is affected indirectly by motor speed. In thin type of connection, a relay coil carries the line current going to the motor. When the motor is started, the inrush current to the running winding, passing through the relay coil, causes the contacts to close, and applies power to the starting winding. As the motor comes up to speed, the current decreases until at a definite calibrated value of current corresponding to a preselected speed, the magnetic force of the coil diminishes to a point which allows the contacts to open to remove power from the starting winding. Capacitor-start and two-value-capacitor hermeticallyscaled motors are usually started with a voltage-type relay. In this method of starting the relay coil is connected in paral lel with the starting winding. When power is applied to the line, the relay does not operate because it is calibrated to operate on a higher voltage. As the motor comes up to speed, the voltage across the starting winding and relay coil increases in proportion to the motor speed. At a definite voltage cor responding to a preselected speed, the relay operates and opens its contacts, thereby opening the starting-winding cir cuit. The relay then keeps these contacts open because there is sufficient voltage induced in the starting winding, when the motor is running, to hold the relay in the open contact position. CONTROL FOR ALTERNATING-CURRENT MOTORS Squirrel-cage motors are usually started at line voltage where power company limitations permit. In sizes up to 5 hp at 220 volts, or 7Yt hp at 440 volts, polyphase motors may be started by means of manual switches having overload current elements for motor protection. In larger ratings a linestarter is usually provided with either an additional safety switch or circuit breaker for disconnecting and short-circuit protection. Reduced-voltage starting may be used when the current inrush on full voltage exceeds the limitations set by the power company. The magnitude of this inrush current is entirely independent of the load on the motor, and is the same whether the motor is lightly loaded or heavily loaded. Restrictions on starting current may limit the maiimtim current inrush or may limit the increments of current inrush which may be drawn on each step. Table 7 shows a comparison of the various methods of reduced-voltage starting. The choice may depend upon the limitation to be met. Fig. 5 shows examples for marimum current limitations. Fig. 6 showB Table 7 .... Comparison of Squirrel-Cage and Synchronous Motor Starting Methods Typ* of Storfcr Pawn! of Motor CaW Value* Voltage Starting Tarqv* lino Current Full Voltage Starter 100 100 100 Autotransformer 80 percent tap 65 percent tap 50 percent tap 80 65 50 64 68 42 46 25 30 Resistor, single step 80 64 80 Reactor 50 percent tap 45 percent tap 37.5 percent tap 50 45 37.5 Part Winding 60* Star-delta 58 * Varies with portion af winding used. 25 50 20 45 14 37.5 . 60* 60* 33 33 examples for increment limitations. The increment starters would not be satisfactory for meeting maximum current limi tations as they exceed the nuariiniim value before the motor reaches full speed. Both Curves B and C.of Fig. 6 would be satisfactory if the increment limitation were 400 percent but only the starter illustrated by Curve C would meet a limita tion of 200 percent increments. When increment starters are used, the motor may not develop enough torque to start until the last step. Fig. 6 shows that with the resistor step starter the motor does not start until Step 3 or after 2 seconds on Curve C. Part-winding motors may start and then stall at about half speed until the second step which applies full torque. - _A MAX MUM CURREMT L1MI TATION /B J--4- kruu. LOAD \ v\ N, O I 2 34 TIMS - SECONDS Curve A--Full Vottogo Starter Curve 8--Reactor 50 Percent Top Curve C--Autotmmformor 55 Percent Tap s e Fig. 5____Starters for Maximum Current limitations Motors and Motor Controls 647 J used for speed-regulating duty, the percent speed reduction, the number of speed control points, and the type of load (variable or constant torque) should be specified. Fig. 8 . illustrates recommended control practice for wound-rotor motors. Synchronous motor starters should provide pull-out pro tection, automatic synchronization or automatic stopping of the motor after pull-out, and assurance of complete start ing sequence, as well as overload and low-voltage protection. The control may be either magnetic or semi-magnetic at full or reduced voltage. Semi-magnetic starters provide automatic field control, but require hand operation for doting the line contactors to start and transfer to full voltage. Curve A--Vaftoge Starter Curve B--Part Winding Starter Carve C--4-Step Reader increment Starter fig. 6 .... Starters for Increment Limitations The load inertia WK* may also affect the selection of re duced current starting method since the reduced torques may not be sufficient to accelerate the load without overheating the motor or in the case of synchronous motors, may not reach sufficient speed to puli into synchronous speed. In these cases the solution may be to use the wound-rotor induction motor or some means of reducing the load such as suction dampers on compressors, fig. 7 illustrates recommended control practice for squirrel-cage motors. Wound-rotor motors require control of both primary"and secondary circuits. The primary* control may be the same as for squirrel-cage motors, manna! or magnetic, at full vol tage. Secondary* control provides means of varying secondary resistance for starting and speed control. The secondary contoller should be specified for starting duty only, or for speed regulating duty. If the secondary controller is to be Amiiigeiuenft 2, 3, 4, and 5 Prorid* Automatic PvA-bvtfoa Starting. fig. 7.... Recommended Controls for Squirrel-Cage Motors fig. 8 .... Recommended Controls for Wound-Rotor Motors In applying reduced-voltage starters to synchronous mo tors it should be remembered that, since these motors are started on damper windings and function during the accelera tion period similarly to squirrel-cage motors, the starting torque varies as the square of the applied voltage. Considera tion should be given to insure development of sufficient mo tor torque to accelerate the load. - Multi-speed control may be either manual or magnetic, and at full or reduced voltage. When using automatic mag netic control with two-, three-, and four-speed separate winding or consequent-pole motors, control may be obtained from a remote point by means of a push button master switch. The various speeds of the motor are obtained from the master switch by simply depresting the correct push button. This is known as selective speed control. It is com monly used in the smaller theater installations where the fan and motor are located backstage and the speed control is located in the lobby. . Multi-speed motor controllers may be provided with com pelling relays which make is necessary for the operator to press the first speed button before regulating the motor to the desired speed. This ensures that the motor is always started at low speed before adjusting to a higher speed. Timing relays which provide for automatic acceleration may be used for control. With this feature the motor will always start at low speed and automatically accelerate to the desired speed. Decelerating relays may be used to reduce the shock effect of the braking action on the motor and drive when the speed is reduced from a higher to a lower speed. Single-phase motor control usually consists only of an across-the-line starter, either manual or magnetic. In some Refer to Giaour et end af chapter. _ 648 CHAPTER 45 1959 Guide cases it is desirable also to provide a disconnect switch. Fig. 9 ' illustrates the recommended controls. MOTOR RATING The rating of an electric motor depends upon the total temperature which the motor attains under operating condi tions. This total temperature depends on both the ambient temperature and the temperature rise of the motor. As motor temperature rise is in turn determined by the ability of the motor to dissipate heat, circulation to the motor should not be restricted. Improper selection of motors with regard to temperature ratings may result in high motor operating temperatures and accompanying reduction in motor life. FUNCTIONS OF CONTROL EQUIPMENT FOR MOTORS In general, control equipment for all types of motors should provide (1) means of disconnecting the motor and controller from the power supply, (2) means for starting the Fig. 9 .... Recommended Controls for Single-Phase Motors motor, (3) overload protection for the motor, (4) protection agninst low voltage, and (5) means for varying the motor speed. Full-voltage starting for motors is preferable because of its lower first cost and simplicity of control. Except for d-c machines, most motors are mechanically and electrically de signed for full-voltage starting. The starting inrush current, however, is limited in many cases by regulations of power companies because of the voltage fluctuations which may be caused by heavy current surges. It is therefore often necessary to reduce the starting current below that obtained by across- the-line starting. The power supplier should be consulted to determine the allowable inrush current for any given location. The choice between full-voltage and reduced-voltage start ing is governed almost entirely by inrush current limitations. The starting torque of all motors varies with the starting current, and it is therefore necessary to insure that the motor is supplied with sufficient current to develop enough torque to accelerate the load. ( In present practice overload protection of motors is ob tained by use of thermal-overload inverse-time-limit type protection. The usual setting of such protection devices is not to exceed 125 percent of rated full load current for open 40 C deg rise motors, and not to exceed 115 percent of rated full-load current for all other motors, the element tripping, after a definite interval of time. The National Electrical Code requires the addition of fuses or circuit breakers to pro tect the overload elements from severe short-circuit currents. Two types of protection are available against low voltage at the motor terminals. One type, called low-voltage release, permits the motor line contactor to drop out on low voltage and to close again when the voltage returns to normal, thereby restarting the motor when the abnormal condition is ended. The second type, called low-voltage protection, causes the motor line contactor to drop out on low voltage, but prevents restarting when the voltage returns to normal except by the action of an operator. This latter type of pro tection is desirable where it is necessary for the operator to make initial starting adjustments on the machine. Manual control for an alternating- or a direct-current motor is usually located near the motor. When so located an operator must be present to start and stop or change the speed of the motor by operating the control mechanism. Manual control is sometimes employed only as a device to give overload protection, and another device is employed to start and stop the motor. Manual control is used particularly on small motors which operate unit heaters, Email blowers,, and room coolers in an air-conditioning system. In other cases manual control in the form of drums, when used with multi- speed motors, is used only as a speed setting device, while the starting and stopping functions operate automatically through thermostats and pressure switches. Because of the increasing complexity of air-conditioning systems, the equipment is operated preferably by automatic control, and less dependence is placed on manual operation and regulation. Automatic control of motor starters may be accomplished by the use of remote push button stations, by a thermostat, float switch, pressure regulator, or other similar pilot de vices. An added advantage of automatic control is that the main wiring for the starter may be installed near the motor, while the starter may be operated by a remote control de vice. GLOSSARY General Definitions ` NEMA is the abbreviation for the National Electrical Manu facturers Association. AEIC is the abbreviation for the Association of Edison Il luminating Companies. . . EEI is the abbreviation for the Edison Electric Institute. Speed Regulation (d-c motors) is the change in speed be tween no load and full load, expressed in percent of full-lead speed; for example, a motor having a no-load speed of 1200 rpm and a full-load speed of 1140 rpm would have a speed regu lation of 526 percent. Slip (a-c induction motors) is the difference between the motor speed, and synchronous speed expressed in percent of synchronous speed, eg., a 1200-rpm motor operating at 1140 rpm would have a slip of 5 percent. Torque is an'expression of the turning effort developed by the motor at the shaft, and is usually expressed in ounce-feet for fractional horsepower motors, and in pound-feet for motors of larger ratings. Primary is the term usually applied to the high voltage or line side'of a transformer or motor. In the ease of the wound rotor motor the primary is the stator winding. Secondary is the term usually applied to the low voltage or load side of a transformer or motor. In the case of the wound rotor motor the secondary is the rotor winding. Motors and Motor Controls 649 NEMA Classification by Mechanical Protection and Method of Cooling These classifications are from NEMA publications MGI120 and MGI-121. Open Machine An open machine is one having ventilating openings which permit passage of external cooling air over and around the windings of the machine. a. Drip-proof Machine. An open machine in which the ven tilating openings are so constructed that drops of liquid or solid particles tailing on the machine at any angle not greater than 15 decrees from the vertical cannot enter the machine either directly or by striking and running along a horizontal or in wardly inclined surface of the machine. b. Splash-proof Machine. An open machine in which the ven tilating openings are so constructed that drops of liquid or solid particles falling on the machine or coming towards it in a straight line at any angle not greater than 100 degree3 from the vertical cannot enter the machine either directly or by 'striking and running along a surface of the machine. c. Semi-guarded Machine. An open machine in which part of the ventilating openings in the machine, usually in the top half, are guarded as in the case of a "guarded machine" but the others are left open. d. Guarded Machine. An open machine in which all openings giving direct access to live or rotating parts (except smooth shafts) are limited in size by the design of the structural parts or by screens, grilles, expanded metal, etc., to prevent accidental contact with such parts. Such openings shall not permit the passage of a cylindrical rod Yt inch in diameter, except that, where the distance from the guard to the live or rotating parts is more than 4 inches, they shall not permit the passage of a cylindrical rod 34 inch in diameter. e. Drip-proof Fully Guarded Machine. A drip-proof machine whose ventilating openings are guarded in accordance with paragraph d, f. Open Externally-ventilated Machine. A machine ventilated by means of a separate motor-driven blower mounted on the machine enclosure. Mechanical protection may be as defined in paragraphs a to e, inclusive. -- g. Open Pipe-ventilated Machine. An open machine except that openings for the admission of the ventilating air are so arranged that inlet ducts or pipes can be connected to them. This air may be circulated by means integral with the machine or by means external to and not a part of the machine. In the latter case, thin machine is sometimes known as separately- or forced-ventilated machine. Enclosures may be as defined in par. a to e, inclusive. h. Weather-protected Machine. Type /--A. An open machine with its ventilating passages so. constructed as to minimize the entrance of rain, snow and air-borne particles to the electric parts and having its ventilated openings so constructed as to prevent the passage of a cylindrical rod 34 in. in diameter. Type II--A machine having, in addition to the enclosure defined for a weather-protectedType I machine, its ventilating passages at both intake and discharge so arranged that high- velocity air and air-borne particles blown into the machine by storms or high winds can be discharged without entering the internal ventilating passages leading directly to the electric parts of the machine itself. The normal path of the ventilating air which enters the electric parts of the machine shall be so arranged by baffling or separate housings as to provide at least three abrupt changes in direction, none of which shall be less than 90 deg. In addition, an area of low velocity not exceeding 600 fpm shall be provided in the intake air path to minimize the possibility of moisture or dirt being earned into the .electric parts of the machine. Totally-enclosed Machine A totally-enclosed machine is one so enclosed as to prevent the free exchange of air between the inside and the outside of the case but not sufficiently enclosed to be termed air-tight. a. Totally-enclosed Nonventilated Machine. A totally-en- closed machine which is not equipped for cooling by means external to the enclosing parts. b. Totally-enclosed Fan-cooled Machine. A totally-enclosed machine equipped for exterior cooling by means of a fan or fans integral with the machine but external to the enclosing parte. c. Explosion-proof Machine. A totally-enclosed machine whose enclosure is designed and constructed to withstand an explosion of a specified gas or vapor which may occur within it and to prevent the ignition of the specified gas or vapor sur rounding the machine by sparks, flashes or explosions of the specified gas or vapor which may occur within the machine casing. Note--See National Electrical Code Article 500--For Haz ardous Locations, Class I, Groups A, B, C or D. d. Dust-ignition-proof Machine. A totally-enclosed machine whose enclosure is designed and constructed in a manner which will exclude ignitable amounts of dust or amounts which might affect performance or rating, and which will not permit arcs, Bparks, or heat otherwise generated or liberated inside of the enclosure to cause ignition of exterior accumulations or atmos pheric suspensions of a specific dust on or in the vicinity of the enclosure. Note I--Successful operation of this type of machine requires avoidance of overheating from such causes as excessive over loads, stalling or accumulation of excessive quantities of dust on the machine. . Note II--See National Electrical Code Article 500--For Hazard ous Locations, Class II, Groups E, F or G. e. Water-proof Machine. A totally-enclosed machine so con structed that it will exclude water applied in the form of a stream from a hose, except that leakage may occur around the shaft provided it is prevented from entering the oil reservoir and provision is made for automatically draining the machine. The means for automatic draining may be a check valve or a tapped hole at the lowest part of uie frame which will serve for ' application of a drain pipe. Note--A common form of test for a water-proof machine is to'play on the machine a stream of water from a hose with a one-inch nozzle delivering at least 65 gpm from a distance of about 10 ft, from any direction, and for a period of not less than 5 min. ' f. Totally-enclosed Pipe-ventilated Machine. A totally-en closed pipe-ventilated machine is a totally-enclosed machine except for openings so arranged that inlet and outlet ducts or pipes may be connected to them for the admission and dis charge of the ventilating air. This air may be circulated by means integral with the machine or by means external to and not a part of the machine. In the latter case, these machines shall be known as separately- or forced-ventilated machines. g. Totally-enclosed Water-cooled Machine. A totally-enclosed mm-hine which is cooled by circulating water, the water or water conductors coming in direct contact with the machine parts. - h. Totally-enclosed Water-air-cooled Machine. A totallyenclosed m*ehin^ which is cooled by circulating air which, in turn, is cooled by circulating water. It is provided with a water-cooled heat exchanger for cooling the ventilating air and a fan or fans, integral with the rotor shaft or separate, for circulating the ventilating air. i. Totally-enclosed Air-to-air cooled Machine. A totally-en closed machine which is cooled by circulating the internal air through a heat exchanger which, in turn, is cooled by circulating external air. It is provided with an air-to-air heat exchanger for the ventilating air and a fan or fans, integral with the rotor shaft or separate, for circulating the internal air and a separate fan for circulating the external air. j. Totally-enclosed, Fan-cooled Guarded Machine. A totallyenclosed, fan-cooled machine in which all openings giving direct access to the fan are limited in size by the design of the struc tural parts or by screens, grilles, expanded metal, etc., to prevent accidental contact with the fan. Such openings shall not permit the passage of a cylindrical rod 34 in. in diameter except that, 650 CHAPTER 45 1959 Guide where the from the guard to the fan is more than 4 in, they shall not permit the passage of a cylindrical rod Y* in. in ' diameter. Motor Speed Gossifications . A Constant-epeed motor is one in which the speed remains practically constant with changes in load; eg., a d-c shunt- wound motor or a-c squirrel-cage motor with low slip. A Varying-epeed motor is one in which the speed varies with the load, usually decreasing when the load increases; eg., a d-c series motor or an induction motor with large slip. An Adjustable-varying-epced motor is one in which the speed can be adjusted gradually, but when once adjusted for a given load will vary in considerable degree with change in load; eg., a shunt-wound d-c motor adjusted by armature resistance con trol. ' . An Adjustable-speed motor is one in which the speed can be varied gradually over a considerable range, but when once ad- . justed remains practically unaffected by the load; eg., a d-c shunt motor with field-resistance control. The standard ratings for open-type, adjustable-speed motors, having a speed range of 3 to 1 and greater are in accordance with the following: (1) A standard continuous horsepower rating at ISO percent of minimum speed with a temperature rise of 40 C. (2) The next higher standard continuous horsepower rating at 3 times minimum speed with a temperature rise of 40 C. (3) Between 150 percent of minimum speed and 3 times minimum speed, the standard continuous horsepower rating with a temperature rise of 40 C will vary with ' the speed along a straight line connecting these two horsepower ratings. No further increase in horsepower is recognised above 3 times minimum speed. (4) Below 150 percent of minimum speed the lower continuous horsepower rating (see preceding item 1) will apply with a temperature rise of 50 C- . Example: 20/25 hp, 400 to 1600 rpm. This motor may be rated 20 hp, 40 C at 600 rpm and 25 hp, 40 C from 1200 to 1600 rpm. Between 600 and 1200 rpm the rated horsepower increases directly with speed from 20 to 25 hp. (5) Motors may also be rated 1. hour with temperature rise of 50 C with the higher horsepower rating (see pre ceding item 2) throughout the entire speed range. Example: 20/25 hp, 400 to 1600 rpm. This motor may be rated 25 hp, 50 C 400/1600 rpm; 1 hour. Mechanical Modifications Vertical Mountings are available for such applications as ' pumps and agitators. This type of application may require a special umbrella-type hood to protect against dripping liquids. Flanged Mountings are available for use where motors are built in as part of machines. Motors may also be supplied with flush plate mountings, suitable for close coupled pump and Bimilar applications. ' CHAPTER 46 RESIDENTIAL SUMMER AIR CONDITIONING Consumer Requirements, Equipment Capacity Selection, Types of Equipment, Types of Systems, Gas Year-round Air Conditioners, Location of Coo/ing Equipment, Noise, Air Distribution Methods, Operating Costs, Effects on Future House Design SUMMER air conditioning in residences has become a tial Air-Conditioning published by the Air Conditioning and major factor in the air-conditioning field and has created Refrigeration Institute. Published procedures of reliable a heavy interest among home-owners, builders, architects manufacturers when used in conjunction with their equip and business men. Residential cooling, particularly for the ment are also adequate. small home, received its initial impetus when equipment spe Both of the industry methods mentioned employ cooling cifically designed for such purposes became available in the load factors for the various components of the load that are 1930's. . averaged over a peak period of several hours and thereby The first installations were made by using commercial and make allowance for thermal storage effects. They avoid the industrial methods as the estimating basis and did not prove possibility of pyramiding non-concurrent, instantaneous peak as satisfactory as the installer or designer desired. Actually, loads. - . the difference between estimating the residential summer air With most methods it is possible to select the desired de conditioning and commercial summer air-conditioning loads sign indoor-outdoor temperature difference, using 80 F or is in the design temperature differences used, the type of in the user's preference for the indoor temperature, and the ternal load in the conditioned area, and the .method of cal commonly used outdoor temperature for the area as listed in culating equipment size. Chapter 13. - CONSUMER REQUIREMENTS Design methods which average load conditions for a period in excess of 12 hr have not been accepted by the industry Present practice is to design residential summer air condi tioning on the basis of an 80 F indoor temperature. In using this basis it is assumed that the home owner will operate the system continuously with a thermostat setting of 75 or 76 F and thereby take advantage of the thermal storage in the house and household furnishings to reduce the peak tempera tures. The preference of the individual home owner must, however, be considered in selecting the design indoor tem perature and may require that a temperature lower than 80 F be selected. Analog computed studies and field investi gations1 have apparently demonstrated the adequacy of the SO F indoor temperature as a ha-cig for equipment selection procedure. To ensure comfort, it is that the proposed opera tion and performance of the system be explained to the user in advance. Usually the greatest degree of comfort um be obtained by keeping the house closed and operating with a fixed thermostat setting throughout the cooling season. In some climates the-opening of the house to utilize night-air coding creates humidity difficulties that take several hours to overcome during the following day. The use of night-air cool ing may lead to unsatisfactory conditions when the equip ment is not turned on again sufficiently early the next day. It will also allow unfiltered air to enter the house thus reduc ing the cleanliness advantage of air conditioning. committees. Such methods require the introduction of fac tors that are not at present considered to be adequately sub stantiated by mathematical analysis or to be justified by the thermal storage effects of a typical residence. The contractor should avoid any capacity selection pro cedure based on a rule of thumb such as 10 average windows or doors per ton or 500 sq ft of floor area per ton. Insulation, glass areas, shading effects, and solar orientation must be given careful consideration by using an accurate, step-by-step procedure for estimating the load. ' In residences, peak lighting loads will not usually occur during the period of greatest load from outdoor temperature and solar conditions. Unlike summer air conditioning in com mercial or industrial establishments where internal heat pro ducing sources may be a major portion of the load, internal loads in residences may generally be neglected except under the most unusual circumstances. The heat and moisture introduced by a clothes dryer or wa ter heater should be vented to outdoors. Heat introduced by the kitchen range should be discharged through an exhaust fan. These are major internal loads that must be taken into account if adequate venting is not to be provided. The load calculation method presented in Chapter 13 is not recommended for residences where it has been found* to result in oversizing because internal loads that are generally a EQUIPMENT CAPACITY SB.ECT10N prime consideration in commercial applications are hot gen erally significant in residences. Furthermore the method out There are two industry-accepted methods of pullulating lined in Chapter 13 gives an instantaneous peak load without residential cooling loads. These are as given in Manual 11, consideration of residential usage and heat storage effects Summer Air Conditioning, of the National Warm Air Heat applied in the ARI and NWAH <fc ACA load calculation pro ing and Air Conditioning Association and Standard 610-56, Application Engineering Standard for Year-Round Residen cedure. Oversizing is objectionable from at least two view points: (1) it increases the capacity and consequently the 652 CHAPTER 46 1959 Guide cost of the equipment installed, and (2) it results in less de sirable humidity conditions within the residence because of. the increased size. TYPES OF EQUIPMENT Low Side Three types of low side equipment (the equipment that actually removes the heat from .the conditioned space) have been developed for residential work as follows: (1) refriger ated coils, (2) chilled-water coils, and (3) water-cooled coils. The first and most commonly used method of absorbing heat from .the conditioned air is to use direct evaporation of the refrigerant in a coil with the air to be conditioned passing over the outside of the coil surface. The heat is passed directly from the air into the refrigerant for removal. This requires the use of an air distribution system and, although generally most economical in new construction, may present costly problems in modernization work where ductwork is not in stalled. . In a chilled-water system, water is circulated through a closed circuit containing two coils. In one coil the water re moves heat and moisture from the air in the conditioned space. In the other coil (water chiller) the heat is removed from the water by mechanical refrigeration. This type of sys tem is called a duplex system in that the heat is picked up by chilled water and later removed from the water by means of a refrigeration system.' - The water-cooled coil sing water directly from city mains or wells is the simplest type of installation but, because of limitations imposed by the capacity, cost, or temperature of the available water supply, its use is not generally practi cable. Cold water is circulated directly through the coil while air from the conditioned space is passed over the coil to re move heat and moisture. After the water has passed through the coil, it is wasted. To operate satisfactorily, an installation of this type requires water of sufficiently low temperature to chill the air enough to remove the desired amounts of heat and moisture. Where a large supply of cool water is obtain able, the water-cooled coil will operate with satisfactory re sults. As a general rule a water-cooled coil should not be used unless there is a supply of 52 F or colder water at the peak of the coding season and in sufficient quantities to take care of the cooling load with a temperature rise of no more than 10 deg. Where water is not obtainable in sufficient quantities. or at the required temperatures, it is necessary to chill the water to the desired temperature by sing mechanical re frigeration. - . High Side . The high side of a conditioning system, the section of equipment that removes the heat from the refrigerant and reclaims the refrigerant for further use in the system may be either the air or water-cooled type. The air-cooled high side is so constructed that the heat is removed from the com pressed or hot refrigerant by passing it into a cooling coil over which outside air (air taken from outside the conditioned area and returned to outside of the conditioned area) is cir culated. ' The major advantage of air-cooled equipment is that no water is required to accomplish the removal of heat from the refrigerant and only an electrical supply is needed. The dis advantage is that operating pressures are higher because of the inability to cool the refrigerant as much by air as by water. This results in an increase in electrical input to the compressor motor. Water-cooled equipment can be of two types. In one type the water drawn from a well or from city mains is passed through the condenser of the high side and is allowed to flow to a drain, swimming pool, a wetted roof, or to other means of disposal. Where the water supply is sufficient and at low cost, this type of water-cooled unit is the better type installation because of lower equipment cost, lower operating costa and quieter operation. In a second type, if water is in short sup ply or is expensive, about 95 percent of the cooling water can be reclaimed by evaporating sufficient water to rid the re maining water of the heat picked up in the condensing unit. This can be done by the use of an evaporative condenser or a cooling tower described in Chapters 38 and 40. TYPES OF SYSTEMS The present generally accepted method of cooling resi dences is to employ a central system. The main components of the central plant for year-round air-conditioning systems may be obtained in factory-made assemblies providing matched components for both winter and summer condition ing functions or they may be obtained in one or more separate parts and combined on the job into an integrated system. Summer conditioning equipment may be obtained separately and added to existing heating systems or may be installed in dependently of any beating system. Cooling coils may be. used in conjunction with warm-air furnaces and duct systems, or chillers may be combined with boilers to provide hot and Mid water for circulation to room units as required. Refer to other Chapters 15, 16, 19, 42, and 43 for information on specific system components. Self-contained room coolers, which arc discussed in Chapter 16, are used for room or spot cooling and are not generally used to cool an entire residence. Their application and use is not to be considered further, but it may be noted that when only a portion of a'residence is cooled the load calculation methods currently used in the industry for central residential systems are not applicable. Refer to Chapter 13 when cal culating the load for such applications. In some areas there is little or no need for heating but there is a distinct need for summer cooling. Both air- and watercooled package cooling units are available for such installa tions, ranging in size from one ton to at least 15 tons capacity. To install these units it is only necessary to make plumbing and electrical connections and add the duct work required to convey air to and from the conditioned space. These units ran also be used to provide central air conditioning for residences Fig. 1 _____Combination Sommer Air-Conditioning and Hot Water Heating System Residential Summer Air Conditioning 653 having hating systems which do not contain provision for blower. The heat is taken from the water vapor, and the wa attaching summer cooling equipment. ter is returned to the generator by gravity to be used again. Year-round air conditioners require less space than a sepa rate heating plant plus a separate summer conditioner. Usu Cooling Cycle ally the heating and cooling portions of a year-round air The gas flame, when applied to the generator of the ab conditioner operate independently of each other. The air cir sorption unit, boils the solution. The water vapor which is culated by the fan passes through the cooling or heating por thus produced goes to the condenser where this vapor is tion of the equipment, only one of which is in operation at condensed. It then flows into the single coil (which is the any one time. evaporator on the cooling cycle). The air being cooled and Air conditioning can be installed in homes having a hot- dehumidified is blown over this coil. The water vapor water heating system by use of either of the following: (through the process of absorption) is returned to the liquid 1. Room un&s resembling convectors and containing both heating and cooling coils. These units are used in place of the conventional radiator or convector. They can be installed in all rooms of the house to provide complete summer cooling, or they can be used in only one or two rooms. This arrangement is shown in Fig. 1. 2. A spUi system. The cooling coil is located in a duct through which air from the rooms is circulated, cooled, and returned to the rooms. Another coil in the same duct can be used for winter heating, or conventional radiators, convectors, or panels con be used to bring heat to the rooms. state and flows by gravity to the generator to be used again. The refrigeration unit is factory-sealed and contains a solu tion of lithium bromide and water which acta as the ab sorbent, water vapor being the refrigerant. Circulation of these fluids in the system is accomplished by differences in temperature and height of liquid columns, without moving parts. Control System ' Manual switches permit the owner to select heating or When the cooling equipment to be used in houses equipped with forced-circulation hot water heating is of the type which produces chilled water, it may be located in the basement or utility room near the boiler. In most of such systems it is then possible, with the addition of suitable valves, to use the same piping system for circulation of heated water in winter and chilled water in summer. The piping must be insulated to prevent sweating when circulating chilled water. cooling, constant or automatic fan operation, and turn the system on or off. For protection of the unit a generator limit switch and a cooling circuit preventive control switch are provided. The former protects the generator from excessive input and is preset to operate at safe temperature levels both on the heating and cooling cycles. The preventive con trol switch keeps the unit from serving as a heating plant if the condensing water were cut off. Another protective de- ` GAS YEAR-ROUND AIR CONDITIONERS vice used in the year-round gas air conditioner is the low temperature control which prevents the unit from freezing Gas-fired year-around air conditioners,based on the ab sorption cycle are available in sizes suitable for residential use and commercial applications. The conditioners are built in 3# ton and 5 ton sizes with _ as a result of improper equipment operation. A fan delay control delays fan operation until the hrat.mg coil has reached 140 F so as to prevent cold air circulation when heat is desired. heating capacities appropriate for various climates. The 3Vz ton and one model of the 5 ton units have hating inputs of LOCATION OF COOLING EQUIPM4T 120,000 Btuh. This makes them suitable for homes having The preferred location for summer cooling equipment will design heat losses up to 76,800 Btuh. The other 5 ton model depend upon the type. In a combination self-contained unit, has an input'of 180,000 Btuh mwiring it suitable for homes the location will depend upon accessibility to the duct system, having design heat losses up to 115,200 Btuh. the fuel supply, the chimney, and the electrical supply. Too Genera! Description often, a heating or cooling unit is located by giving considera tion to installation only, without considering the usability of The principal components of- the gas-fired year-round air conditioner are an absorption unit, a gas burner, a cen trifugal fan for air circulation, a filter section, and controls. The gas flame supplies the heat to actuate the absorption unit which provides heating in ranter and- cooling in sum mer. The entire unit operates under a vacuum at all times. The absolute pressure within the generator and condenser on cooling cycle is of the order of 2 to 2Yt in. Hg (50 to 60 mm) absolute pressure. The pressure within the cooling coil and the basement. This may result in breaking up the basement area to such an extent that it becomes practically useless for other purposes. In a remote type combination unit, considera tion must be given to the location of the condensing unit, whether it is located in the basement area or whether the unit is located in a remote area such as the garage breezeway. Preferences of the family and their habits of living must be giyen consideration so as to keep all space as useful as possi ble and still locate the equipment in such a place that it can do its intended job and be accessible. absorber is between 0.25 to 0.3 in. Hg (6 to 9 mm) pressure. On the beating cycle, since the ram** coil is used for both heating and cooling, the absolute pressure is on the order of 14 in. Hg (350 mm) or about Vi atmosphere. NOISE One of the prime problems with residential air-conditioning installations is the operating noise level. Almost any degree of quietness in an installation can be had for a price. How Hearing Cycle ever, the numerical standards for describing sound levels have little meaning for the average person. It is difficult to The gas flame, when applied to the generator of the ab sorption unit in winter, boils the solution. The water vapor which is thus produced goes directly (bypasses the con denser) to the angle coil over which air is passed by the ascertain from the prospective user in advance of installation just what sound levels will be acceptable and to describe what sound levels will result from any particular arrangement. Motors and motor drives, comoressor, blower, pumps if 654 CHAPTER 46 1959 Guide any, apd flowing air and liquids are potential sources of noise and vibration. The first, and frequently the least expensive and most effective measure in noise reduction, is to put dis tance between the noise and the listener. Installations of cool ing equipment in basements, crawl spaces, utility rooms or attached garages are preferable to those in alcoves or closets adjacent to bedrooms and living rooms. Mounting of units on concrete floors is preferred. Further steps which may be t-nWpn to achieve an acceptable low noise level are as follows: 1. (he production of noise and vibration. Use only true, concentric pulleys with smooth belts at the proper tension and use properly balanced blower wheels and other rotating parte, operated at the minimum practical speed. Provide an mtaqiTtP duct system which promotes smooth air flow at reasonable velocity and is sufficiently rigid in construction so that it does cot vibrate unduly. 2. Prevent the transmission of noise and vibration to the house structure and to duets and piping. Use properly loaded isolation mounts for compressors, even when on concrete floore, and provide vibration isolators on blowers and refrigerant lines and vibration loops in the refrigerant system. Install flexible connections between the cooling unit and the ductwork. 3. Control airborne noise with sound-absorbing material or other pr*>nirwl treatment. Install sound-absorbing material within ductwork and, where practicable, use one or more elbowB between the equipment and the registers or grilles. be maria for different air-flow rates for summer and winter. In warmer climates, however, where air conditioning is the primary consideration, the summer air-flow rate may be used the year around. The registers may be placed either in the high ride-wall or in the perimeter location. For the high ride-wall applications, it is necessary that the deflection of the air be different for glimmer than it is for winter to prevent the jet from dropping into the living zone (60 in. above the floor and below) where the velocity should be not greater than 35 fpm. For registers located at the perimeter of the residence,' it is not necessary to change the deflection from summer to winter. The air distribution system should be designed for the largest air-flow rate that is to be used, as outlined in Manual 9 of the National Warm Air Heating and Air Conditioning Association. For snail-pipe perimeter systems, it is necessary to have , more outlets than for the larger duct systems. In some applications, it may be necessary to close off some regis ters during the winter so that adequate register air velocities will be obtained. These registers would then be opened during the summer to give a sufficient number of outlets. Recent investigations have shown* that the use of perim eter-duct systems for air conditioning gives excellent results, anH that objectionable air motion does not occur within the AIR DISTRIBUTION METHODS living zone except in the immediate vicinity of the registers. Care must be taken, however, to use only registers or diffusers Systems should be designed and installed by competent that are specifically designed for perimeter application. This engineers in accordance with authoritative information such is necessary to permit the introduction of the air into the as given in th? design of the Air-Conditioning and room in a pattern that does not cause drafts. Floor diffusers Refrigeration Institute* and the National Warm Air Heating which distribute the air in a fan-shaped pattern along the nd Air Conditioning Association.4 The rises of the ducts of wall or low ride-wall diffusers which blanket the wall are year-round air-conditioning systems are often larger than recommended. For supply-air temperatures not more than those of equivalent winter beating systems since large quanti 15 deg below room-air temperatures, diffuser face velocities ties of cool air, at 55 F to 65 F, must be circulated through of 500 fpm are recommended.' For supply-air temperatures them. 20 deg below room-air temperature, the diffuser face velocity Several manufacturers have developed reliable methods of should not be less than 700 fpm. duct defflgn Such methods should be used when recom Many registers for outride wall application may mended, since they take into account the specific air-flow and not be satisfactory for cooling when applied to low-velocity static pressure characteristics of the systems to which they systems because the coo] air is apt to remain at the floor. apply. They should, however, be applied with caution to sys Ceiling diffusers may also be used, but they may lead to tems and equipment other than those for which they were difficulty during the heating season if the warm air remains developed. at the ceiling, resulting in cold floors. Cooled air admitted to rooms from ducts through supply High return locations at inside walls are very effective with outlets is from 15 F to 25 F adder, and therefore heavier, outride wall or floor perimeter distribution systems for both than the air in the room, and has a natural tendency to drop the HAnting and cooling season. In multi-story or split-level toward the floor. Unless the supply outlets are properly se dwellings there should be a minimum of one return on each lected, located, and adjusted, the air distribution is likely to level with a high central return on the upper level to minimize result in a low velocity of cool air falling on the occupants or the effects of hot air rising through halls and stairways to up a high velocity stream of cool air striking a wall or other per levels. With filing or high-inside-wall distribution, the obstruction and deflecting on the occupants. A further returns should be located on the outride walls under windows complication is introduced when the same outlets are used for best results. for Hasting in which case the delivered air at temperatures considerably above room temperature has a tendency to CONTROLS rise. Where cooling is installed with ducts and air outlets that Control devices and systems and their application in resi dential air conditioning are discussed in Chapter 43, Auto : serve the <vHng function only, the practice and experience matic Control. of comfort air conditioning for offices and commercial build ings apply directly to residential installation. Although cool- OPERATING COSTS _ ing and hating by means of the same ductwork and air out The operating cost of residential cooling equipment during lets has been common practice in commercial and industrial a particular summer depends on variables such as the applications, greater care must be taken in residential appli- amounts of sunshine and rain, the number of abnormally cations. It has been found that low air-flow rates (much lower hot or cod days, the efficiency of the equipment, and the local than would be used for cooling systems) are desirable for power rate. It is also influenced by human factors such as warm air heating systems* It is therefore recommended that, operation of equipment only during the hottest weather, in a residence located in a moderate or cold climate, provision opening windows at night* and difference in preferred indoor Residential Summer Air Conditioning 655 Table 1 ... Approximate lew Input per 12,000 Btuh Cooling Capacity Horn ot Power Load Type of Heat Rcjorffewi* Wafer Cooled Coadefiter City Water Atmos pheric Coofirtg tower Mechani Air cal Draft Cooled CeoSng Con Tower denser Refrigeration Compressor....... Blower for Air Conditioner . .. Blower for Rejection Air......... Pump, Cooling Water............... 1.00 0.10 -- -- 1.00 0.10 -- 0.15 1.00 0.10 0.15 0.15 1.35 0.10 0.15 -- Total kw per 12,000 Btuh 1.10 1.25 1.40 1.60 * Other best rejection mens* include -well*, *pry pond*. evaporative condeaeers, water coilsin the ground, fiaoad ntcr octls in air, etc. temperatures.** Nevertheless, it is important that landing agencies and prospective buyers of equipment be given a rea sonably accurate estimate of the operating cost during nor mal summer weather and under usual operating conditions. Adjustments can then be made for any special conditions anticipated. The approximate electrical power inputs for the various motorized components in mechanical cycle air condi tioners are shown in Table 1. Power cost per hour can be estimated by multiplying the estimated power per ton, the cooling capacity in tons and the cost per kilowatt-hour. Thus the estimated cost per hour for a 3-ton air conditioner cooled with city water will be 1.1 kw X 3 tons x the power rate. It is essential to use the cor rect step of the utility residential rate structure to get a good estimate. The basis of the method used11 requires the use of a table of the estimated annual hours of operation for properly... sized equipment in typical cities. See Table 2. -' The values in Table 2 have been substantiated by utility records of actual performance in several major cities when the average indoor temperature is maintained at 80 F. Low indoor temperatures increase operating cost as do weather conditions above normal. Water usage is another important factor with water-cooled equipment. Various manufacturers have published water us age data for their equipment at varying summer water tem peratures. Representative water consumption values are given in Table 3. For a given application the power rate and water rate may be obtained from the local utilities. Since the average power requirement depends on the particular equipment used and Table 2 .... Estimated Annual Hours of Operation for Properly Sized Equipment in Typical Cties during Normal Cooling Season Ofy Cy Hoar* Table 3 .... Water Usage for Water-Cooled Equipment Sommer Water Temperature, Normal Extreme* F Gallon* Per iHourl (7oa| Summer Water Temperature, Normal Extreme* P GaDoat Per (Hour! (Tm) 55 34 75 58 60 39 80 70 65 44 85 88 70 50 the condensing method, values obtained from the manu facturer should be used in preference to those in Table 1. If the evaporator fan cycles with the compressor, the power requirement as found from Table 1 also represents the total power requirement for air-cooled condenser applications. For continuous fan operation the number of hours of compressor operation should be subtracted from the number of hours in the cooling season to obtain the extra hours of fan opera tion. This value may then be used with the appropriate value of power consumption and power cost for the fan motor only, to find the added power cost for continuous fan operation and the result should then be added to the power cost during compressor operation. For wateT-cooled condenser applications the water cost, as determined from the operating hours, water rate, anH manu facturer's data on equipment water usage, is added to the power cost to obtain the estimated total operating cost. Another method has been developed using cooling degree days above 70 F as a criterion but tabulated values of cooling degree days, for various localities are not available.* Approxi mate values can be obtained from degree-day maps.*1 " The daily range of temperatures for various localities is alan required with this method.* It is important that the method used in estimating operating cost be consistent with the method used in calculating the heat gun of the structure. EFFECTS ON FUTURE HOUSE DESIGN Air conditioning, like automatic beating, brought about improved practice in residential construction, particularly in those regions where cooling is of primary importance. Al though it is true that construction practices which reduce the heating load also reduce the cooling load, there are certain considerations that are unique in their effect upon the cooling load. Special attention should be paid to window orientation and shading. South windows may be shaded by awnings or roof overhangs, but it is not practicable to shade large win dow areas having an east or west orientation except by ex terior solar screening of some type. The use of insulation in the walls and ceiling of the residence will reduce the cooling load appreciably. In addition, attention should be paid to adequate ventilation of the attic. Double-glazed and weather- stripped windows, heat-ab6orbing glass, planned tree locations, and light-colored exterior wall and roof surfaces, also help to reduce the cooling load. Cleveland, Ohio.. . Dallas, Texas............... 1400 Fresno Calif 900 St. Louis, Mo................ Washington, D. C........ 1000 800 REFERENCES . *T. N. Willcox, C. T. Oergel, 8. G. Reque, C. M. toeLaer, and W. R. Brisken: Analogue computer analysis of residential cooling loads (ASHVE Transactions, Vol. 60, 1954, p. 505). 'H. T. Giikey, D. R. Bahnfleth, and R. W. Roose: Cooling a small residence with a two-horsepower mechanical iwnHumring unit (ASHVE Transactions, Vol. 59, 1953, p. 283). 656 CHAPTER 46 1959 Guide * Application Engineering Standard for Year-Round Resi dential Air Conditioning (Air Conditioning and Refrigeration Institute, 610-56). 4 Summer Air Conditioning (National Warm Air Heating and Air Conditioning Association, Manual No. 11, 1955). Continuous Air Circulation (National Warm Air Heating and Air Conditioning Association, Manual No. 6, 1955). M. E. Childs, R. W, Roose, H. T. Gilkey, and S. Konzo: Comparative Performances of Two Warm Air Perimeter Sys tems and Three Convection Systems (University of Illinois, Engineering Experiment (Station Bulletin 403, 1942). TD. R. Bahnfleth, C. F. Chen, and H. T. Gilkey: Cooling a small residence a perimeter-loop duct system (ASHVE Transactions, VoL 60, 1954, p. 271). ' H. E. Straub and S. F. Gilman: Room air distribution research for year-round air conditioning. Part II--Supply out lets at three floor locations (ASHVE Transactions, Vol. 60, 1954, p. 249). A. P. Kretz, M. K. Fahnestock, and 8. Konzo: Investiga tion of Summer Cooling tn the Warm Air Heating Research Residence (University of Illinois, Engineering Experiment Sta tion Bulletin 290, 1930). " R. A. Gonzales: How power usage varies for summer air conditioning of identical residences (Refrigerating Engineering, January 1957, p. 35). "T. N. Wiilcox: Annual utility cost operating residential cooling system (Fuel Oil News, June 1954). "S. F. Gilman, L. A. Hall, and E. P. Palmatier: The oper ating cost of residential cooling equipment (ASHVE Transac tions, Vol. 60,1954, p. 525). "S. 8. Visher: Relative cooling requirements for American homes (.The Scientific Monthly, November 1945, p. 211). "E. N. Kemler and 8. Oglesby: Heat Pump Applications (McGraw-Hill Book Co., New York, 1950, 1st ed., p. 246). "Summer Weather Data (The Marley Co., Kansas City, Kansas, 1939, Chapter VI). CHAPTER 47 SCHOOL SYSTEMS Genera/ Consrderofionz, Criteria for Design, Design Considerofions. Preliminary Design, Mechanical Plant Design, Types of Ventilating Systems, Types of Heating and Cooling Systems, Automatic Control, Operation, Maintenance he purpose of this chapter is to outline the factors af requirements. Many schools include multipurpose rooms Tfecting the selection of heating, ventilating, and air serving as auditoriums, gymnasiums, and community centers. conditioning systems for schools. The components of these The normal periods of operation are five days per week systems are the same as used for other types of buildings. for nine months per year, with complete shutdown during Their combination in school systems, in some cases, will be ' the same as for other buildings, but may differ considerably in others in order to provide optimum conditions for effec tive school work and to comply with local regulations. week-ends and vacation periods. Few schools operate during the summer months and therefore do not require complete air conditioning, except in southern climates. Systems for administration areas, gymnasiums, auditoriums, and multi purpose rooms, suitable for community activities, will often GENERAL CONSIDERATIONS be operated at times when the systems for classrooms and other general educational areas may not be in operation. The proper criteria for heating, ventilating, and in many Automatic control of temperature and system equipment instances air conditioning, of school buildings, particularly is a necessity if comfortable conditions are to be obtained. classrooms, are often not recognized fully. Proper application of controls may return the cost of in Many designers and school administrators approach the vestment by savings in labor and fuel within a year or two. problem as one of heating, whereas analysis may show Frequently, insufficient consideration is given to provi that cooling, rather than heating, is required during periods sions for access and maintenance with the idea that the of occupancy throughout most of the year. Ventilation mechanical system is a fixed part of the structure and should systems are frequently designed to supply air at 72 F for last as long as the structure, without attention. ventilation and, when feasible, at 55 F to 60 F to provide School boards are often criticized by their constituents for the cooling required during occupancy. spending large sums of money for so-called luxury items, with With regard to ventilation, code requirements vary from the result that economy in construction and design becomes acceptance of natural ventilation, such as obtained by a paramount factor. This often tends to limit size of the me opening of windows, to a requirement of mechanical supply chanical equipment selected below that required to maintain of a specified quantity of air, which sometimes is as high a proper indoor atmospheric environment. However, many as 30 cfm of outdoor air per occupant. The variations in schools in areas having warm spring and fall climates are now quantity of outdoor air specified are due to the basis adopted being designed to include air conditioning, at least in spaces whether it is the quantity needed to replace oxygen for of densest occupancy and greatest use. breathing or that required for the dilution of odors. A discussion of air requirements will be found in Chapter 6. CRITERIA FOR DESIGN When planning for introduction of ventilation air into Comfort, cleanliness, reduction of odors, maintenance of rooms, careful consideration should be given to air dis alertness, compliance with codes, installation cost, ease and tribution and circulation within the occupied space, as well cost of upkeep, cost of operation, and adaptability to con as the natural convection and temperature effects. trol in relation to periods of use as related to outdoor con Elementary schools of recent design are generally single ditions are the chief; criteria by which a design for main story buildings, often placed at considerable distance from tenance of indoor environment for learning may be judged. each other. They are often provided with windows 7 ft Comfort, which may be defined as freedom from strain in or more in height extending the full length of one or more accommodating to the environment, is a necessity. Uniform . classroom walls. These large glass areas constitute one of ity of air movement and temperature within the space is re the greatest problems in maintaining an optimum indoor quired to provide a comfortable environment. Fundamentals atmospheric environment. in this respect are discussed in Chapter 6, Physiological Secondary or high schools are more often two- and three- Principles, and Chapter 20, Air Distribution. Intermittent story structures but present problems only slightly less currents of air or air movement at varying velocities may severe than grade schools. Separation of school buddings result in discomfort. Similarly, variations in temperature results in increased cost of the mechanical systems. may contribute more to discomfort than uniform main-, A further characteristic of school buildings is a wide tenance of slightly higher or lower temperatures. variation in use and occupancy. Classrooms (the largest Odors, while they may not be deleterious to health, are single group of occupancies), lecture rooms, assembly rooms, disagreeable and distracting, even to the point of being nau auditoriums, and other similar areas have uniformly dense seating. Odors should not be perceptible in schoolrooms. occupancies. Gymnasiums, cafeterias, laboratories, shops, Local codes may establish requirements for construction, and similar functional spaces have lighter occupancies and glass areas, ventilation rates, etc., which exceed values used also have different and varying ventilation temperature in normal design practice. 657 658 CHAPTER 47 1959 Guide An-nrCfiTn n- WINDOWS ON 0W SIDE OUTDOOR TEMR.-F Basin Root area--1000 sq ft. Windows on oae tide only--240 tq ft. Heat liumiuuMn fbdan, V; roof--0J5, <rafl--0.25, gfcu--IJ3. No infiltration. Hoof gain* based on artificiaf fighting at 2.3 watts per tq ft of floor area. Occupant*, 35. Solar intensity and incidence at 45 deg N. latitude, Oecmatter I. WbeJowt shaded by Venetian bEnds. Since the coaiiderotioo is coating, a roam fimpuiuhnu of 75 F, instead of the 72 F diovn m Table J, was ased m the above charts. Net cooling requirement for the sooth exposure approach** ftaf of the north *xpo*ure oa o day when the sty bos a heavy chad cover. fig. 1.... Typical Net Heating and Cooling Requirements of Classrooms Installation cost is a prime consideration in design. It should be considered in relation to the overall cost of school operation. The cost of maintenance is reflected in man hours required to provide proper operation and reasonable life of the equipment. Proper location, access, and working space for the equipment are reflected in reduced operator or custodian time. Some systems require more frequent attention, overhaul, or replacement than others. Operating costs may be held to a minimum by: (1) selection of the proper fuels for system requirements based on fuel eco nomics in a particular area; (2) providing flexibility for operation of sections of systems according to use; (3) provision of adequate automatic temperature control and system control. Periods of use contemplated for the entire school building, or sections of it, due to summer school, or community use of an auditorium throughout the summer or during spring and fall months (in a region where these are mild) may influence a decision to include air-conditioning systems. DESIGN CONSIDERATIONS Design for the required indoor environment for learning must be made in consideration of the heat losses, heat gams, and air movements; ventilation means and ventilation rates; space temperature requirements; variability of occupant density; independent operation of various spaces; practi cability of cooling; means of cooling (if it is to be included in the design); and automatic control of the environment. A typical illustration of beat losses and heat gains in classrooms is presented in Fig. 1, applicable for sun effect to about 45 deg north latitude and design temperature for heating of 0 F. For the classrooms shown and based on the construction and conditions described in the footnote, heat gains in the classroom with north exposure equal the heat losses at 32 F. In the south classroom, practically no heating, is required after the room is occupied and lighted. Ac cordingly, heat is required in the south classroom only for warm-up. Cooling is required in north classrooms at out door temperatures above 32 F and, in south classrooms, at all temperatures above 0 F. Conditions shown for the north classroom would apply to a south classroom when the sky is fully overcast. " chop* of craiMwobcn. Temperatures ore often lower; mlocSms often higher. fig. 2....Natural Air Currentsin Gassrooms Natural air movements or air currents prevailing in the space must be taken into account in design. Fig. 2 illustrates two conditions: the first having windows located along one ride, the second having windows for cross-lighting. Measured conditions are shown for classrooms of the first type. It is significant, as will be noted in these illustrations, that, even though the room temperature at the control point may be at the desired level, uncomfortable conditions could be expected for the students in the first or second rows paralleling the windows. Direct radiation installed at the glass exposures cannot be fully effective in wanning the descending currents of cold air unless it extends the full length of the windows, is located close to the window sill, and is in operation whenever the outdoor temperature is low enough to cause these downdrafts. Ventilation means and rates are largely fixed by state and municipal codes and vary considerably with type and intended use of any building. Applicable ventilating systems are shown in Table 1. Natural ventilating systems are those relying on opening of windows to admit and exhaust air. Mechanical supply or exhaust systems are those using fans to supply or exhaust air. Natural ventilating systems are not suitable for spaces such as gymnasiums, auditoriums, cafeterias, and meeting rooms, because of size or density of occupancy; nor for laboratories, large toilet rooms, locker rooms, or kitchens in which intense odors are common; nor in shower rooms where high vapor concentrations are likely to occur. It is not possible to obtain consistently good room conditions in classrooms by means of any ventilating system that depends on openable windows for introduction of air. This is the case with each of the natural ventilation systems shown in Table 1. The problems are due to the following factors: - 1. At low outdoor temperatures, the windows are kept closed, resulting in high odor intensities. 2. As outdoor temperatures rise, up to temperatures of 60 F, uncontrolled, uncontrollable, and variable drafts will occur in the occupied sone. Typical conditions are shown in Fig. 3. 3. Frequent adjustment of window openings by the in structor, with consequent distraction from tmr.hing duties, will be necessary to provide adequate ventilation without excessive drafts and to maintain proper room temperature. 4. Manual readjustment of window openings is an erratic -method of controlling ventilation. . 5. The advantages of saving time and obtaining greater ac curacy of temperature control are lost. School Systems 659 Space Table I____Applicable Ventilating Systems and Room Temperatures Naiorat Natural with Nateiai with Mednuitcol Supply Median*of Supply, Gravity Exhaust Ahchanicai Exhaust and Exhaust Gravity Exhaust 4. Kitchen 8. Locker Rooms 12. Showers No* No No No No No Yes No No If Code* Yesd No No* No No No If Codeb- No Yes Yes* No* If Code* Yes* No No* No No No If Code* If Code* Yes Yes* No* If Code* Yes4 No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes No No Yes No No * 8abjet to condition. See tart. b If permitted by code. * Utti*** rooms ere interior. * If roam* ra smell end Room Temp F 72 60-70 65-70 65-72 75-60 72 65-70 70 75-60 Temperature requirements of various spaces depend on occupancy, function, degree of activity, and type of clothing. Values generally accepted are listed in Table 1. In meeting spaoes such as auditoriums, cafeterias, gym nasiums, and the like, the variability of occupant density may warrant the use of separate units or systems for the several spaces in order to permit their individual operation without operating the entire school system. It may be practicable to counteract the net heat gains shown in fig. I or some of them by cooling with ventilation air or other means besides refrigeration. This would require the use of mechanical air supply with sufficient cooling capacity at a 55 F outdoor air temperature to offset the net heat gains. If the amount of air required results in an excessive cost of the mechanical system, a study should be made of means of reducing the various cooling load sources, particularly the solar load. When outdoor tem peratures are in excess of 65 F, windows with ample opening - to produce rapid changes of air in the space, are necessary to maintain comfortable conditions, unless cooling by re frigeration is installed. When the outdoor temperature is above 65 F, relatively high velocity air movement in the space is not objectionable from the standpoint of comfort. Even under the most favorable conditions, ventilation sys tems eannot maintain comfort when the outdoor tempera ture exceeds 72 F. DESIGN OF THE MECHANICAL PLANT Heating, ventilating, and cooling loads are computed ac cording to the procedures given in Chapters 9, 11, 12, and 13. The performance requirements of the various parts of the system, whether combined or operating separately, according to use, are then established, with due considera tion being given to the method of control and operation of the entire school project. Heating requirements should be determined for design conditions and. for warm-up periods, the heaviest warm-up load being that which occurs after a weekend shutdown when the outdoor temperature is at de sign value. - The load applicable during occupancy, considering net heating and .cooling loads, is determined and evaluated as shown in Fig. 1. If planned use of the building extends through the summer, cooling design dry-bulb temperatures used are those established by the ASHAE Technical Advisory Committee on Weather Design Conditions which are shown in Column 6 of Table 2, Chapter 13, and referred to as "TAC 2Yt% Basis." Design temperatures in common use, both dry- wet-bulb, may also be found in the same table in Columns 7 and 8. For detailed analysis of frequency of occurrence of extreme conditions by months, reference may be made to Region Climate Analyses and Design Data, published in 1951 by the American Institute of Architects. These analyses are available for all United States areas. The requirements of each of the mechanical systems in corporated in a school plant are as follows: 1. An adequate warm-up rate for heating, the ability to raise room temperatures to required conditions shown in Table 1 within an acceptable interval of time when the out door temperature is at design value. Usually, warm-up re quirements after a weekend shutdown are used as a basis. 2. Maintenance of indoor design temperature when cooling is required. Considering the heat gains drown in Fig. 1, a typical analysis of ability to provide cooling with outdoor air is shown in Fig. 4. 3. Uniformity of air motion, discussed - under Criteria for . Design. Generally this requirement is satisfied by a system providing constant air flow, with proper distribution of the air supplied. 4. Uniformity of temperature of supply air, discuoed under Criteria for Design. 5. Introduction of ventilation air, according to applicable codes; otherwise on a rational basis, as discussed in Chapter 6 for quantity and Chapter 20 for distribution. 6. Interception of deflection of window drafts in rooms having extensive fenestration, such as classrooms. (See Fig. 2.) 7. Acceptable noise levels which will depend on location of the school and on the equipment provided. TYPES OF VENTILATING SYSTEMS Any ventilating system provides air circulation and thus includes means of supply and exhaust. Ventilation systems may be classified by the type of supply (window or mechan ical) or exhaust (window, gravity, or mechanical). Air Supply Methods . Windows are generally of double bung type or consist of metal architectural sections, the bottom section being ar ranged to swing inward to deflect air upward and the top section to swing outward from a hinge at its top or center. If double bung windows are used, a deflecting device, gen erally of glass, to prevent interference with light transmis sion, is provided at the bottom to deflect incoming currents upward, as illustrated in Fig. 3, and thereby prevent them from blowing directly on room occupants at desk level. Since windows require mantm! opening, proper control of air currents cannot be provided. ..Mechanical air supply is generally provided by a central . / i 660 CHAPTER 47 1959 Guide Sajed on <rmd normal to oxpoturej room 25 ft deep/ window* doMehong, 5 ft wide, 2 window* opened o* dtown. Rg. 3 .... Typical Air Row in Classrooms with Natural ' Ventilation duct system, the air being delivered through wail grilles or ceiling diffusers, or by self-contained units within the rooms, such as unit ventilators and unit conditioners located at the outside walls. Grilles are generally located most con veniently at the inside or corridor wall. They must be- of the deflecting type, deflecting upward in consideration of the drop in the air stream when air is introduced at lower than room temperature. Diffusers are generally located in railings of rooms in a pattern to provide proper air dis tribution! In location of both wall grilles and diffusers, it is important that the air-delivery path be free of obstruc tions, which might be light fixtures and crossbeams, since presence of obstacles ('will result in uncontrollable and turbulent currents of air extending into the occupied zone and rising drafts. Grilles and diffusers are generally se lected to provide a terminal velocity of' 50 fpm at. ap proximately one-fourth the distance from an opposite wall or other obstacle to air flow. ' Exhaust Methods Window, when used for exhaust, are opened at the top to take advantage of natural rise in the warm air to be exhausted. Windows are 1 not fully effective for exhaust purposes, except in completely still weather. Typical con ditions are shown in Fig. 3, indicating that, if the'windows are on the windward side, air is introduced rather than exhausted. - Gravity exhaust ventilation is obtained through exhaust grilles in the ceiling (or in a wall away from the windows) Softs: Cooling requirements shown in Fig. I. A Ne* hoot goto wHh rentitatian air controlled at room temperature of 75 F. 8, C, and 0 = Nef boot gouts using 525. 1000, and 1500 cfa, rospoc- tivefy, controlled to 55 F, minimum. Cooling air temperature wtil be higher os outdoor air temperature rite* above 55 F. Rg. 4... Typicaj Cooling Capacities, Using Outdoor Air connected to roof ventilators. Air is exhausted by wind effect chimney effect due to differential pressure re sulting from thermal head. This type of exhaust is used in conjunction with air supply obtained by admitting air at the windows. Satisfactory air changes can be obtained- by this method within limits shown in Fig. 3, if the room ventilators are adequately lafge. However, room conditions cannot be fully acceptable, since objectionable cold drafts are certain to occur in cold weather. Control of conditions depends on manual adjustment of window openings, a method that is reasonably satisfactory only in mild climates, but is not recommended where the design temperature is lower than 30 F. Gravity exhaust ventilation may be used with satisfactory results in combination with mechanical air supply systems. In mechanical exhaust systems the roof ventilators de scribed in preceding paragraph on gravity exhaust ventila tion are replaced with motor-driven exhaust fans. If this system is used in conjunction with window supply of air, it should be remembered that when windows are closed, replacement air is drawn from the corridor or the ventila tion rate is greatly reduced. At such times, negative pres sures will prevail in the building, with adverse effects on incinerators, hooded equipment, and other local exhaust and fuel-firing equipment. TYPES OF HEATING AND COOLING SYSTEMS Systems may be classified according to methods of heat ing and cooling. Each may be combined with means for ventilation in various ways. Only a few states have specific requirements with respect to types of systems. Accordingly, except in these states, engineers and administrators of school construction are free to analyze and choose kinds of sys tems. The possible combination of such systems are ex tremely numerous. A discussion of those encountered most often will follow. Direct Radiation This type of heating includes cast-iron radiators, castiron or nonferrous convectors, and continuous finned-pipe heating elements in connection with steam or water heat ing systems (see Chapters 14, 26, and 28). The radiation must extend the full length of the outside or window walls and the full width of high windows used in cross-lighted designs illustrated in Fig. 2. Control is obtained by manual valves, by individual automatic control valves for each room, or by an automatic valve or valves controlling zones of the system according to exposure. Direct radiation may be used with natural ventilation, natural ventilation with gravity exhaust, and natural ven- Schoo! Systems 661 Ration with mechanical exhaust. It is designed for the warm-up load and to provide a warm curtain of rising air to mix with the incoming cold air to temper it. However, ' it is inadequate for this purpose, because heating require ments are satisfied at relatively low outdoor temperatures as soon as classrooms are occupied and lighted, as illustrated in Fig. 1. The system requires the teacher to adjust open ings for ventilation. Installation costs can be relatively low. described in Chapter 19: Air supply may be controlled by zones of similar occupancy and identical orientation. In dividually controlled booster or reheat coils may be located within ducts leading to each of the spaces. Individual room control may also be provided by a double duct system, equipped with mixing dampers for each room located within a short distance ahead of .the supply grilles or diffusers serving the room. Central air conditioning can be included. Electric Heating This consists of electrical heating elements in baseboard type of radiation extending the full length of the window walls, electric ceiling panels, or panels formed of heating cable buried in the ceiling plaster. Control of heating is automatic by means of individual room thermostats. Any of the ventilating systems discussed previously can be com bined with electrical heating, much as discussed under Direct Radiation. Electrical heating has the same short comings as direct radiation; namely, that when classrooms are occupied and lighted, heat is not available for counter acting downdrafts at windows. The system requires the teacher to adjust openings for ventilation. The cost of energy will depend on the local electrical rates. Panel Healing . Floor panel heating is adaptable to the slab-on-ground type and to the open-corridor type of school, particularly in the wanner climates. Design data are given in Chapter 30, Panel Heating, which also describes features of panel heating control systems. (See also Chapter -43, Automatic Control.) The floor system lends itself well to individual room,control, although zone control, including several rooms of the same exposure in the same zone, is practicable. Floor panel heating systems are adaptable in areas having design temperatures down to 0 F. Since the requirement for heating is materially reduced when the spaces are oc cupied and lighted, as illustrated in Fig. 1, the panels'should be constructed to have minimum mass and thus minimum storage effect. This -is accomplished by using a slab, only sufficiently, thick to enclose the tubing or piping, underlaid by a slab of insulating concrete. Even with light concrete panels, there is enough storage effect to cause overheating after warm-up and to make it difficult to follow rapidly changing loads. Any of the types of ventilating systems already discussed may be combined with panel heating systems. However, the panel heating system cannot be effective in combating the natural condition of downdrafts at the windows. The system requires the teacher to adjust openings for ventilation. The panel system is well adapted for use in primary classrooms with slab-on-ground floor construction, where students spend much time on the floor. Central Indirect Air Systems In these systems, air is supplied for ventilation and heat ing. At a central point or points, outdoor ventilation air and recirculation air is mixed and heated by automatically controlled steam or hot water coils. Gravity or mraha.niral exhaust is coordinated with the air supply system. The central system can be arranged to recirculate air from window sills to intercept the flow of uncontrolled cold window drafts into the classroom. Such returns are fully effective only if the openings are located in the window sills; if located below the sills, the natural air currents will not be intercepted. There are many variations of the system, which may include features of central systems Split Systems The central indirect air systems may be combined with direct rodiatitin or convection units described in the pre vious section. Direct Radiation. In this combination, air may be supplied by the ventilating system at constant temperature, usually 55 F, when the outdoor temperature is less than 55 F. In this case direct radiation may be de signed to take care of the building heat loss. In order to prevent window drafts, the temperature of the ventilation air should be controlled to require operation of the direct radiation when the outdoor temperature is below 55 F. The direct radiation is controlled by automatic valves operated by a room thermostat for the individual room. This system - has wide flexibility. `- Central Direct-fired Air Systems . These systems are forced circulation warm air furnace systems. They may be arranged for single or double duct air distribution, as discussed under Central Indirect Air Systems. This type of system is further discussed in Chapter 18, Warm Air Heating. They are usually installed with zone controls and arranged to permit use of any desired proportion of outdoor air during periods of space occu pancy. Mechanical cooling may be obtained by installation of cooling coils in the main supply ducts. Unit Ventilators Unit ventilators are used in classrooms to provide heat ing, controlled ventilation, and cooling, using outdoor air as the cooling medium. Auditorium unit ventilators are used in large rooms such as auditoriums, gymnasiums, and large lecture rooms. Classroom unit ventilators are often combined with matching storage cabinets or may be com bined with ducts extending the full length of the windows and arranged either to discharge air' upward along the window sills or withdraw air at the window sills and thereby prevent downdrafts from the windows. In order to effect ively intercept natural downdrafts, the return grille must . be located with the top of the unit at the level of the win dow sill. Classroom unit ventilators may also be combined with extended finned-pipe radiation at) the window sills to combat cold window downdrafts. Electrical unit ven tilators are also available. Unit ventilators using hot water for beating and chilled water for cooling are used for school buildings where year-round use is contemplated or where warm fall or spring seasons warrant the installation of air conditioning equipment. These units and their controls are described in Chapter 15, Unit Ventilators and Unit Heaters. The noise level of the unit ventilators under the operating conditions of the installation should be considered. These systems have a high degree of flexibility. Unit Conditioners Unit conditioners are essentially the same as unit ven tilators, discussed above, except that the cabinets contain refrigeration equipment, a direct-expansion coil, and a steam or hot water coil piped from the central boiler source. Noise 662 CHAPTER 47 1959 Guide levels of unit conditioners are generally somewhat greater than those of unit ventilators. Unit conditioners are described in Chapter 16, Unitary Air-Conditioning Equipment. automatic control Discussion of automatic control in t)m chapter will be limited to general factors peculiar to school systems, and their effect on control or the need for it. Chapter 43, Auto matic Control, provides a detailed discussion of the proper application of mitematie control to the various system dements normally encountered. . Automatic temperature control equipment is justified in school systems because manual control will not maintain the temperature or environment within desirable limits. Automatic control, maria an integral part of the system design, can reduce the initial cost of the mechanical in stallation. Examples of t.h type of control include warm up clocks or low-limit thermostats, which prevent the use of outdoor air until the building has been heated for a set period of time, or until a minimum space temperature is reached. Such controls permit selection of the minimum sue of equipment such as boilers, furnaces, burners, coils, piping, etc., having the least excess capacity for warm-up purpose. Controls to prevent the heating of service water in large storage tanks during the warm-up period accom plish a similar result. Controls which reduce the man-hours of attendance at the heating plant or reduce fuel costs, can reduce operating costs. Time docks, relays, temperature and pressure con trol, which allow the starting of the heating plant without the presence of supervising personnel, are included in this category, together with controls to reduce the use of out door air during warm-up periods. Where fans and extended surface coils are used to main tain the temperature in an occupied space having outside exposure, it is not possible to control the capacity of the equipment manually without producing alternately high and low space temperatures because of the rapid changes in load due to shifting occupancy, variation in solar intensity, and wind variation in speed or direction, and the relatively high capacity of this type of equipment. Where occupancy is particularly dense, the changes in load due to changes in occupancy alone are enough to make proper automatic control oeoeesary in order to maintain space temperatures within acceptable limits. This applies to a large percentage of the spaces in a school building. There are many other factors or conditions that make proper automatic control necessary in order to achieve ac ceptable environmental conditions. Those already discussed illustrate some basic considerations in applying tempera- ture control to mechanical systems for schools. OPERATION The proper method of operation of a system depends upon its design and the automatic control applied to it and will vary with each individual system. To insure good operation throughout the life of a system, it is essential that adequate written instructions be prepared and made readily available to the operating personnel. There should be at least two copies of the instructions, one of which should be placed in a secure depository to insure its pres ervation in good condition during the life of the building. The operating personnel should be thoroughly instructed regarding proper operation of the equipment upon com pletion of the installation. Someone having authority in the school administration, in addition to the operating person nel, should be instructed in the operating characteristics of the system, not only to insure that a change in the operating personnel does not result in the loss of knowledge required for the proper operation of the system, but also to insure that the operating personnel adheres to the in structions. It is seldom that the personnel in charge of the operation of a school system has training particularly applicable to the characteristics of mechanical equipment or the auto matic control applied to it. Therefore, it is essential that this type of operating personnel be made to understand the exact limits that must be observed in adjustment and opera tion of the system. Where temperature control is applied to a system, it must be realized that any instrument used for control purpose is of necessity very sensitive to any change or adjustment made in the setting of the instrument. Therefore, It is necessary that only personnel fully trained in the proper handling of the instruments should make adjust ments other than those expressly designated as proper for the operating personnel. It is common practice for officials in large school districts where there are many buildings to employ specialists ac quainted with the adjustment of critical items of equip ment such as temperature and automatic control. Where in dividual schools do not have such personnel available, it is necessary that the operating personnel be instructed to communicate with qualified service agencies to make changes in automatic control settings and instrument characteristics when they are found to be necessary by experience in the operation of the system. Continuing service contracts for proper maintenance of equipment can be had from compa nies in this field. When systems are installed and designed on the Haris of natural or gravity ventilation, the teacher or person in charge of the individual room or space must perform the functions of adjusting window openings or ventilator settings to provide the conditions of comfort and proper environ ment in the space. To accomplish efficient operation of the system and maintain a suitable environment, it is necessary that these people be instructed in detail regarding the techniques necessary to achieve the proper environment. It is necessary that the administrative authorities super vise the maintenance of such conditions by periodic checks on the efficiency of the people responsible for the spaces. MAINTENANCE OF MECHANICAL SYSTEMS Hie proper maintenance of a mechanical system will re sult in a minimum of repair and the extended life of the system equipment. As is the case with operating instruc tions, it is essential that written instructions for the main tenance of the system be prepared and given to the owner when the system is completed and placed in his charge. These instructions should include detailed information on the lubrication and care of each item of equipment. A schedule showing items of maintenance to be performed for each month of the year should be prepared. - Name plates and identification for each valve and item of equipment should be prepared. Manufacturers' catalogs and parts lists for the equipment should be obtained. One copy of each of these items should be placed in a secure depository, together with the operating instructions. A list of-the proper service agencies should be prepared and placed in the hands of the operating personnel. Any changes in service agencies should be recorded for the benefit of the administration as well as the operating personnel. CHAPTER 48 TRANSPORTATION AIR CONDITIONING Railway Passenger Car Air Conditioning: Passenger Bus Air Conditioning; Automobile Air Conditioning; Aircraft Air Conditioning; Ship Air Conditioning, Heating and Ventilating, Air-Conditioned Space Treatment, Systems and Controls HE principles of air conditioning applying to stores, panel duct increases air flow and improves heating surface Trestaurants, hospitals, theaters, and homes are - ap effectiveness. plicable to railway passenger cars, passenger buses, auto Floor beat is supplied by introducing steam into an inner -mobiles, streetcars, trolley coaches, airplanes, and ships. tube within a finned tube or by means of a separate steam- However, equipment used for mobile applications differs to-liquid heat exchanger. The liquid (usually an antifreeze) from that used for stationary purposes in that it must is mechanically circulated through plain finned tubing. meet additional requirements. Equipment must be compact, When steam is used directly, the tube-within-a-tube con accessible for quick inspection and servicing, light-weight struction makes it possible to obtain uniform distribution and unaffected by vibration and impact. Freedom from throughout the length of the car. It is achieved by means vibration which could be transmitted to supporting vehicle of heat transfer between the steam within the inner tube and thus to passengers, is essential and the condensate returning in the annular space between RAILWAY PASSENGER CAR AIR CONDITIONING the tubes. The finned tubing at the floor must have sufficient ca The railway passenger car represents a vefy difficult air conditioning problem. Space is strictly limited so that all equipment and ducts must be reduced to minimum size. Electric power supply and water supply also are limited. All equipment must withstand severe vibration and shock, and must be very reliable anr servicing points are fre quently far apart. During the heating season it is necessary to heat con ventional cars with steam from the locomotive at pressures that may vary from 250 prig to only 5 or 10 prig on the last car in long trains. Passengers in window seats sit only a few inches from cold outride walls and windows, and are close to heating surfaces installed along rides of cars. Sudden changes in load-may be caused by changes in sun, wind, or train movement. Even in coldest weather, outside doors must be opened frequently. During the cooling season, the problem is further com plicated by a highly concentrated internal load due to the passengers. Air distribution problems are. increased by low ceilings and short air throws. Heating ' pacity to offset effects of cold walls and windows during normal operation, and to heat the entire car to a minimum temperature of 60 - during standby when the overhead system is not operating. The maximum capacity required (determined by standby requirements) varies with car construction and design temperatures, but is approximately 90.000 Btu per hour. This requires a heating capacity in finned tube of approximately 650 Btu per linear foot. The overhead air heating coil must have sufficient ca pacity to. heat the outdoor air brought into the car for ventilation, and to supply approximately 20 percent of the internal heat loss of the car so as to permit supply of floor heat at all times at an output that will not be objectionable to passengers sitting near it. The usual ca pacity of the overhead heating coil is approximately 100.000 Btu based on 2400 cfm of circulated air, with 600 cfm of this being outdoor air for ventilation. All Btu values are approximations of actual heating requirements, and do not include heat losses in the trainline (or leakage) or losses in the undercar piping. Present car designs have enabled the car builder to run the steam supply lines in recesses within the car body; thus greatly diminishing The heating of passenger cars is accomplished by using under-car losses. a split system consisting of an overhead air-circulating system with heating and cooling coils, and heating surfaces Refrigeration (floor heat) along car sides. The floor heaters, which usually For cooling and dehumidification during summer, re consist of finned tubing, may be made more effective by frigeration may be obtained from ice bunkers, steam-jet addition of covers designed to increase gravity air circula systems, or mechanical compressors (driven directly from tion, and to direct the warm air from finned heating sur car axle by electric motors or by gas engines). Refrigera face along cold outride walls and car windows. In some tion required varies with load conditions, but 7Vfe tons new cars, wall convector panels are used and extend the per car is one capacity frequently used. Evaporative-type full length of the car, with air intakes along the floor and condensers are sometimes used in combination with the outlets at window sill height and at window head height in dead-light panels. The heated panel protects passengers usual air condenser on either steam-jet or mechanical re frigeration. from cold outride walls, and the chimney - effect of the When an electric motor (approx. -10 hp) is used to 663 664 CHAPTER 48 1959 Guide drive the air-conditioning compressor, the electric power source is a problem. If the power source is an axle-driven generator, there is an appreciable increase in the drag on the locomotive. The power available for refrigeration, when train is stopped at a station, it limited to storage batteries. One solution to this problem is to use a direct-current generator driven by a gas engine. Another is to use a Diesel-driven alternator in a special head-end car to furnish power to the entire train. Recently there have been in stallations in which a Diesel-driven alternator is mounted on an individual passenger car to supply the power re quirements of the car. The attractiveness of this. type of ingtAiiftfinn can be increased by utilizing spare alternator capacity in winter for electric heating. If this capacity is supplemented by exhaust heat from the Diesel engine, there is sufficient capacity to heat the entire car and to provide hot water for washrooms when outdoor tem peratures are above approximately 30 F. This feature is important on trains using Diesel locomotives, since it eliminates the need for operating the steam heating boiler in the locomotive during a portion of the year. Air Distribution and Geaning Railway cars present critical problems in air distribution because air space per passenger is small (60 to 190 cu ft), and the sun load is great. An average passenger car con tains approximately 5000 cu ft of air, and may seat as many as 80 passengers. The occupants are continually liberating heat, carbon dioxide, moisture, odors, and some organic matter from their breath, skin and clothing. The heat and moisture can be removed by cooling and de humidification, but the other constituents can be success - fully handled only by proper ventilation and air cleansing. In an average car, from 3)00 to 2500 cfm are circulated by the air-conditioning unit. Some of this air may be re circulated, but a portion of it should always be brought in from outdoors. The amount of outdoor air desirable depends upon the type of car, number of passengers, air temperature, humidity, odors,' and whether or not the occupants are smoking. It will vary from 15 to 90 percent of the total air circulated. Careful attention must be exercised in specifying the rate of outdoor air taken in so as to fit the type of service adequately, and yet not supply more ventilation than is' necessary. Conditioning of this outdoor air is a major factor in determining size of both summer and winter equipment. ' For normal conditions, 10 cfm of outdoor air per pas senger are provided. When smoking is permitted, at least 15 cfm should be admitted. In some dining cars, and deluxe sleeping cars, outdoor air rates as high as 20 to 30 cfm per occupant are used. A ceiling duct lengthwise along the i center of the car is usually used to distribute .the air to the interior by fans or blowers. A perforated ceiling supplied from an overhead duct, or delivery grilles and plaques designed to give considerable entrainment and mixing, .are used to deliver air to the car space. Smoking rooms present a special problem. The cloud of smoke that usually hangs near the ceiling can be broken up by directing incoming air along the ceiling at a velocity somewhat higher than that used for the rest of car. The air is exhausted .through the washroom or lavatory. For compartments, provision is made in the door or partition for removal of used air. Lower berths are provided with a low-velocity air outlet. Recirculating air grilles are usually of straight-flow types. Outdoor air intakes are usually located in the vestibule, on the side of the car, or on the roof, depending upon location of the cooling coils. On many air-conditioned cars, there are no dampers or shutters at the outdoor air in takes; the percentage of the outdoor air is controlled by adjusting flow through the recirculating grille. Many coach cars are now being equipped with return-air ducts fitted in the structure of baggage racks. Part of the air circulated is returned to the blower unit through these ducts, and part through the car body. This arrangement reduces quantity and velocity of air returning through the car body, and removes smoke fumes at the source. This, and any other design features aimed at taking recirculated air at the floor and adjacent to both end doors (rather than drawing all recirculated air to one end of the car) also reduces infiltration of cold air in ankle-height strata, when doors are opened during the heating season. All air circulated by the blower is filtered before passing over the cooling and heating coils. In some cars outdoor air and recirculated air are filtered separately before mixing, while in others air from the two sources is mixed before passing through a common filter. Filters in use are combinations of metal, wool, cloth, spun glass, hemp, paper, hair, and wire screen. Most filters have a viscous coating of oil for greater cleaning efficiency. Some types may be cleaned, re-treated, and re-used, while other types are dis carded' when dirty. Applications are also being made of electric precipitation for air cleaning. In this system the coarser particles are removed from the air by mechanical separation; finer materials, by electrostatic action. Activated carbon units sometimes are used in addition to the regular filters for adsorbing odors and other impur ities, thus reducing the amount of outdoor air necessary for ventilation. - Temperature and Humidity Control Controls in a passenger car should be as automatic as possible. The regular train crew cannot be relied on to make adjustments for the comfort of passengers. For this reason the latest systems of temperature control have only an off-on switch to be operated by the train crew. When the system is in operation, heating or cooling is provided auto matically as required. When heating, it 13 important that floor-heat finned tubing be controlled at stable temperatures. Wide fluctu ation in its temperature is highly objectionable because of location close to the passengers. Stable operation may be secured by cycling the floor heat on the basis of indoor con ditions in conjunction with an overhead air-circulating system to maintain final car temperatures. Because of window condensation and other problems, no attempt is usually made to raise relative humidity ' in a railroad car in winter time. When cooling; the steam-jet refrigeration system is controlled in an on-off manner. Some means are ordi narily provided for operating mechanical compressor systems at partial capacity. In this case split evaporators are used, so that evaporator surface and compressor ca pacity can be reduced together under light load conditions.. Attempts have been made in the past, largely on an experimental basis, to control the relative humidity in railway cars. This was done by operating the air-con ditioning equipment according to outdoor' temperatures Transportation Air Conditioning 665 and then re-heating the air to an acceptable temperature. 100 percent when the heating or cooling load diminishes. This was found to be an expensive method of operating The distribution ducts and diversion-damper arrangement and the results did not justify the cost. A common method of. this system mako available two supply ducts and one of controlling heating and cooling is to provide a thermo return duct for heating and for cooling, with a change stat to control heating only and a separate thermostat set over to all three ducts to supply air during the inter at a slightly higher temperature to control the cooling mediate ventilating cycle. This system permits utilisation equipment. This obtains heating control, ventilation, and of atmospheric cooling and ventilation "to the greatest cooling control and the reverse, as the case may be. A car degree when it can be most economically employed in in service can go from heating into cooling in a very short the interval between the heating and cooling demand. time. An example of this is found on the- full-dome cars Conventional throw-away type filters or renewable fil in service on several railroads in the country. In the early ters are used in intake air ducts for many vehicles. Electro morning hours before sunrise, the car may be requiring static filters have been successfully used in some instal a considerable amount of heat. Shortly after sunrise, the lations. The need for elimination of dirt is great, but the car may go into the ventilating cycle and as the sun load problem is complicated by space limitations and limited increases, cooling may be required. On the majority of power. car heating systems, frequent cycling of the compressor is prevented by the one degree difference between the heating Refrigeration and cooling control points and by lag imposed on the system by applying artificial heat to the heating ther mostat when cooling is required. On some car heating systems, a degree of modulation is obtained by the use of split evaporation. This requires two cooling thermostats with one of them set at a somewhat higher temperature than the other. The lower temperature cooling thermostat controls a portion of the cooling capacity and, if unable to maintain the car temperature, the higher thermostat adds the remaining capacity. - Summer conditioning systems for inter-urban vehicles range in cooling capacity from 36,000 to 48,000 Btu per hour. Mechanical. compression systems nsing refrigerants are used, and are powered by water-cooled gasoline engines of approximately 14 hp. Complete systems add from 800 to 1300 lb to the weight of the coach. Sometimes an auxiliary generator driven by the refrigeration system engine is used and serves to help charge the bus battery, thereby offsetting power drain imposed by the ventilating blower. Belted recip PASSENGER BUS AIR CONDITIONING The passenger bus designed for urban transportation operation presents a greater problem to the designer of heating systems than does the inter-urban"-bus. More frequent stops, and rapidly changing passenger load cre ate this problem on urban vehicles. Provision of heat for the driver independent of the passenger heating sys rocating compressors and direct-driven V-type and rotary compressors are used, with engine speeds up to about 1800 rpm. Air-cooled condensers for this service require about 5000 cfm of outdoor air, and this is provided by either cen trifugal or propeller type fans belted or direct-driven by the air-conditioning engine. Preventing noise and vibration from affecting passengers is of vital importance. Installations must be made for quick daily engine servicing. In all cases tem, is a further problem. The inter-urban bus, however,"' fuel is obtained from the main bus tanks, and in some, the is usually a deluxe vehicle and may require a comfort cooling system. Space and weight limitations and vibration must be considered. ' main engine cooling system cools the air-conditioning en gine. Heating .. . Control Recent designs 0/ bus heating systems obtain unproved air distribution. Heat in the engine coolant liquid is used to warm air by means of suitable finned coils and this heated air is distributed throughout the passenger space by ducts and outlets directed toward the floor. Some designs include finned surface near the floor in an appli cation similar to that in railway passenger cars. Forced air circulation over this finned floor-beating surface has been provided to increase its effectiveness. Oil-burning booster heaters have been applied to many Dieselpowered buses to raise the temperature of the engine coolant for maximum engine operating efficiency, and to provide sufficient heat for the passenger space. The simplest control system for heating of buses consists of a single thermostat, located in the passenger section to start and stop the blower of the heating unit. This' method of control is not generally satisfactory because, without con tinuous air circulation, temperature gradients from floor to ceiling and from front.to rear are quite pronounced. A more satisfactory method- of control provides for continuous fan operation whenever heating is required. In this method a thermostat, usually in the return air to the heater, operates a modulating valve in the supply line to the heater to throttle the flow of engine coolant to the beater coil in accordance with bus interior temperature. On some systems a means of remotely adjusting the control point of the thermostat is provided at the operator's location. Automatic means are. Ventilation available for starting and stopping booster beaters in the engine coolant system, under control of the thermostat. Also, Air for ventilation is usually brought into a bus at the some systems provide for automatically stopping the Mower front, and distributed throughout the length of the pas of the heater unit and the booster coolant pumps when no senger space by a duct or ducts near the ceiling. Except for a few designs employing 100 'percent outdoor air beat is required in the bus. Outdoor air for ventilation, drawn into the bus by the heating unit blower, is usually not auto for heating, no heating of the ventilating air has been provided. One type of distribution system for an inter- matically controlled but is preset, either by means of a man ual damper or by sizing the outdoor-air intake to provide the urban bus provides for a fixed minimum of outdoor air, and . desired amount of outdoor air. is arranged to increase the percentage of outdoor air to On buses equipped with mechanical refrigeration for air 666 CHAPTER 48 1959 Guide conditioning one method of control includes a thermostat located in the passenger section to start and stop the refriger ation compressor. If the compressor is driven by the bus engine a clutch is provided which can be energized or de energized by operation of the thermostat. On systems em ploying a compressor, driven by a separate engine, automatic means of starting and stopping the engine are controlled by the thermostat. Modulating control of engine driven compres sors may be accomplished by automatic control of the engine throttle by a thermostat in the passenger section. Some sys tems provide for continuous operation of the compressor when cooling is required, the compressor being manually started by the operator. Temperature in the interior of the bus is maintained by reheating the air from the cooling coil. Automatic control of temperature is provided by a thermo stat in the passenger space or the return air to the blower which operates a modulating valve on the engine coolant supply to the reheat coil. AUTOMOBILE SUMMER AIR CONDITIONING The basic components used for automobile air condition ing are fundamentally the same as in any stationary air conditioning system using the vapor compression cycle. Fot automobile application the source of power is always a major obstacle to overcome. -The best solution to date for automobile applications is to operate the condensing unit by belt drive from the car motor and then control the variable refrigerating capacity caused by the variable car motor speed by suitable means. ' One to seven or more horsepower are required. Compres sors must be capable of operating at speeds of 4000 to 5000 rpm to last in this service. Refrigeration capacity re quired is about lYi to lVi tons. Radiant heat, as well as high conduction heat gain due to single-glazed large glass areas, and lack of adequate insulation in car bodies require this much capacity. Proper air distribution to avoid undesirable drafts on passengers also requires careful design. Air distribution fans and electrical controls secure power from the car's electrical system which in some cuas may require heavier generators and batteries to handle the load. Most systems weigh about 200 lb or less. - Early designs, and many current ones, have the cooling units installed in the rear of the car with the cooled air in troduced through the package shelf at the rear of the pas senger compartment. Cooled air is then distributed with or without ducts. Warm air is returned through a grille in the package shelf, or below the rear seat, thence through a filter into the cooling units. Refrigerant lines from con densing unit to cooling unit are carried from the engine compartment to the luggage compartment along the car frame under the body. Performance at open-road speeds has been very sat isfactory (even with early systems--when they were oper ating properly). Twenty percent or more outdoor air should be supplied, especially if passengers smoke. This air may be picked up by scoops on the side of the car or cowl, carried into the cooling unit, and mixed with returned . warm air from the car. Car temperature control, - compressor capacity control to compensate for the variable compressor speed, and prevention of ice formation on the evaporators (a common fault of early systems) are accomplished by bypassing compressor discharge gas into the low-pressure side of the system, or cycling the compressor with a magnetic clutch. The'solenoid bypass valve or a magnetic clutch b electrically operated by a thermostat,' usually controlled by the return air to the cooling unit. The bypass b opened or the compressor stopped when the air gets too cold. A recent development b a complete factory-assembled system, charged with refrigerant and ready to run, whieh b dropped into position ahead of the fire wall of the car and bolted into place. Flexible suction, liquid, and dis charge lines are used to connect the refrigeration com ponents together. This facilitates initial installation. It Altai simplifies removal for service and maintenance and eliminates the necessity to open the refrigeration compo nents to the atmosphere with resultant loss of refrigerant or infiltration of mobture into the system. This system combines winter heating with summer cooling. It also permits use of all or limited quantities of outdoor air, with or without heating or cooling. Outdoor air b taken in through cowl openings. This air b then pulled through a combined heating and cooling coil as sembly by a fan inside the car on the fire wall. Cooled air b discharged from adjustable nozzles on the dash inside the car. Hot air for heating is discharged onto the floor as with conventional car heaters. Dampers change the air distribution from heating to cooling, and dash controls activate or shut off either heating or cooling. Temperature control, prevention of evaporator icing and compensation for variable compressor speed are con trolled by a thermostat with bulb in the air leaving the evaporator. This cycles the compressor on a magnetic clutch. Public acceptance of current offerings has been excellent. Performance has been very satisfactory. What service difficulties have been encountered have been readily cared for by car dealers who have trained personnel to render this type of service, or by competent refrigeration service organizations. Future demand b estimated as high as 10 percent of total car production by one major manufacturer, while another estimates a million or more of its cars will be equipped in the not too distant future. AIRCRAFT AIR CONDITIONING In recent years, heating, cooling and ventilating of air planes has progressed from comparatively simple systems to highly complex multi-purpose designs. The attendant control problem has become correspondingly complex. On older, non-pressurized planes, the heating system consisted either of a steam boiler and radiator or a single stage or double stage heat exchanger. On both types, the cabin temperature was adjusted by positioning the face and by pass dampers. While these were sometimes moved by an automatic modulating control, in the majority of cases they were positioned by one of the ship's crew. As these planes cruised at less than 200 mph and normally operated at low altitudes, changes in outdoor air temperatures were generally gradual enough so that manual readjustment of controls could maintain reasonably comfortable cabin con ditions. Nearly all of these heating systems were marginal in respect to heat available, and the main problem was lack of heat, rather than inadequate control. Non-Pressurized Cabins With the advent of the combustion type beater, and use of larger and faster planes, use of manna] controls be- Transportation /Ur Conditioning 667 impracticable. The combustion type heaters reach full rating in less than a minute after being turned on, and as they are rated at 100,000 Btu per hr and up, and ninr* several heaters are generally used, it would take full time of one crew member to keep cabin temperature regulated. As ships of this type are not pressurized, the heating system is still comparatively simple. In one type, two 100,000 Btu heaters are placed in parallel positions and the ram air from an external scoop is passed through the heaters and discharged through a series of distributing outlets located in the cabin ceiling. The cabin air is discharged through grilles located in the bottom walls of the cabin- An auxiliary nose heater is used by the crew to obtain additional heat for the cockpit or for windshield de frosting. - The cabin is maintained at the desired temperature by means of an automatic control which operates both heaters simultaneously. This control consists of two duct ther mostats, one being mounted in the air inlet duct between the air scoop and the heaters so that it is affected by outdoor ambient temperatures, and the other being mounted in the beater outlet duct so that it is affected by the discharge air temperatures. A thermostat in the cabin is so located that a continuous stream of cabin air passes through it. This type of control has been found to ' respond to a 1 deg temperature change in less than a second. As the outdoor temperature starts to drop, the outdoor air duct thermostat decreases in resistance, unbalancing an electronic bridge. This unbalance is amplified by vac uum tubes and causes a power tube to close a relay, turning on the combustion heaters. The.. resulting in crease in temperature is sensed by the warm air duct thermostat which increases in resistance, thus rebalancing the bridge and causing the relay to open. If there were no loss by radiation or convection from the aircraft cabin,___ these two duct thermostats would be sufficient for--adequate control. However, the cabin thermostat is given approximately 30 times more influence than the duct thermostats and so acts as the master controller, and the duct thermostats prevent overheating or underheating and keep the discharge air from alternating between extreme cold and extreme heat. In a slightly - more elaborate system, two combustion heaters supply a plenum chamber which is maintained at a constant temperature. Air from the plenum chamber is then mixed with outdoor air to maintain desired cabin tempera ture. All of the warm air is discharged into the cabin through the walls. The discharge grilles , are located on the floor under seats, and a modulating-type controller varies pro portions of heated and outdoor air necessary to maintain desired cabin temperature. The same type of control system as previously described is used, except that an amplifier operates a two-phase motor capable of position ing control dampers instead of operating a relay which would merely open and close the fuel valve. An auxiliary ' duct, running from the plenum chamber, is used by the pilot as a source of windshield defrosting air. Pressurized Cabins With the. advent of the new high-speed pressurized transport planes, and the addition of cabin cooling in addition to beating, the control problem becomes more complex. On all of these airplanes, the heat of compres sion from cabin supercharger must be controlled, the air cycle or expansion turbines must be turned on and also, the beat exchanger or combustion heaters, which are used in the system when cooling is required for additional heat, must be automatically controlled. , Assuming that one of these airplanes is operating in an extremely cold climate, the sequence of operation would be as follows: The automatic controller for the supercharged-air inter cooler would be in full closed position, so that none of the heat of compression would be removed, and the air would bypass the expansion turbine and its compresor and the secondary after-cooler. An additional automatic controller would be op erating the combustion heater and supplying the additional heat necessary to maintain the desired cabin temperature. If a heat exchanger were used as a supplemental source of heat, a modulating control operating a damper on this exchanger would run towards full heat position. As the airplane enters a warm climate and beat requirements drop, the combustion heater would cease operation or the heat exchanger would go to full cold position, and the modulating control on the supercharger compressor would move towards the cold position. When the outdoor ambient temperature rises so high that cooling is desired, the cabin supercharger inter cooler would be opened wide. If further cooling were required, the air would go into an air cycle turbine, which is modulated to deliver the required amount of cold air to maintain a comfortable cabin temperature. Pressure in the cabin is maintained by providing a controlled, constant rate of air flow into the cabin suf ficient to maintain ventilation, and adjusting the cabinpressure relief valve setting, by means of a cabin pressure selector, to maintain the desired cabin pressure. limits on maximum inside to outride pressure may be of the order of 4. or 5 psi, and safety controls should be provided to prevent exceeding this limit. There is a maximum rate at which the cabin can change to a newly selected value, this rate being in some cases also adjustable. The requirements for controls of this nature are ex tremely rigid. It is commonplace for ships of this type to experience changes in outdoor ambient temperatures of as much as 100 deg in a space of 5 min For this reason, speed of sensing a change and rapidity of response in the control system is essential if satisfactory control is to be accomplished. The older type thermostats cannot be used in airplanes, due to mass of the thermostat and to vibra tion experienced on all airplanes. All modern controls use some type of. bridge system with temperature-sen sitive resistors as sensing elements. In some types of controls, the bridge system feeds a sensitive balanced relay, which in turn runs a modulating motor or controls an on-off power relay. A recent sensitive and quickly responding type uses an electronic amplifier, which in turn controls a two-phase motor, or, through relays, controls a d-c motor, or merely closes and opens a power relay for on-off applications. ' In addition to extreme speed and accuracy which are required of all aircraft temperature controls, they must be able to operate under great extremes of temperature, pressure and humidity, and also withstand continuous extreme vibration. Heaters should have, in addition to control from thermostats, suitable limit controls to pre vent overheating due to failure of air supply, or any other cause. Also, there should be safety devices to shut off fuel in case of flame failure. On the latest high speed jet airplanes, the temperature control problem is still more severe than' on the latest transports; as in addition to the accuracy required, con trol response must be phenomenally fast. For example, 668 CHAPTER 48 1959 Guide on some, the air going to the cabin from the jet engine compressor can change the temperature at the rate of 150 deg per second. This, coupled with the fact that on smaller size pursuit ships air is changed in the cabin -as much as four times per minute, makes the instantaneous winging of change and an extremely rapid control move ment essentia]. Also, in airplanes operating at Mach numbers in excess of 0.7, the control must react to the large adiabatic temperature rises encountered. SHIP AIR CONDITIONING In air conditioning a ship, the designer is faced with, all problems that would normally arise on shore installa tion plus additional factors. Mechanical ventilation is an absolute necessity for the comfort of passengers and ships' pprannnftl, and for utility and preservation of cargo and stores. Ships are constructed with water-tight bulkheads dividing the vessel into several compartments. This com plicates the running of ductwork and results in a multi plicity of both supply and exhaust fans. Temperature and humidify requirements of various spaces aboard ship vary widely. Passenger staterooms and public spaces must have year-round air conditioning .which is also being applied more and more to the quarters of the officers and crew. Boiler rooms, galleyB, laundries, etc., must have venti lation, and some must have tempered air. Cargo spaces are quite likely to need dehumidification in addition to ventilation. Inasmuch as ventilation is such a necessary factor aboard ship, the majority of recently built vessels have been utilizing the air distribution system for heating purposes. A ship is a self-contained structure quite likely to be away from repair ports for long. periods. Adequate spare parts, therefore, form an integral part of equip ment furnished. The same type of equipment should be used in as many places as possible throughout the ship, in order to reduce the number of spare parts to be carried. Preliminary system design is simplified by uniformity of conditions' which apply to most ships. Among such conditions are: (1) the necessity for the vessel to supply its own power, (2) the availability of an rnilimitaH supply of low cost steam at suitable pressure, (3) limitations of available spaoe and permissible weight. The problem of heat transfer and insulation must be given careful consideration. .The thermal conductivity of ship building material, such as steel, copper and brass, is many times the value of building material used ashore. The length of ducts 'between heat sources and fans ne cessitates extra duct insulation. Hull insulation must be of high quality, with attention given to fireproofness, low density, low thermal conductivity, ruggedness, vermin re sistance, and ease of application. Board types are most common. ' Duct insulation must have the same characteristics as hull insulation. Semi-rigid, and rigid board are most com mon. Corrugated asbestos is not used because in the presence of moisture, it tends to disintegrate. There is a growing .use of natural cork on chilled air ducts because of great difficulty in applying an adequate vapor seal due to space limitations. SHIP HEATING AND VENTILATING . It is usually most economical in weight and space to use steam duct heaters for heating spaces served by mechanical- supply systems. Spaces which do not have mechanical supply, or do not require ventilation in cold .weather, are heated by steam convectors or, where the load is large, by unit heaters. Ventilation air, except that supplied to' auxiliary and main machinery spaces, is usu ally preheated to temperatures of 50 to 70 F. No re circulation is used in ventilation and heating systems, but a manna! reduction (25 to 50 percent) of air quantity is made during the heating cycle. Ail heaters are auto matically controlled, and preheaters are designed and in stalled to minimize possibility of freezing of condensate.. Preheaters are frequently located dose to the outdoor air intake in order to conserve insulation and, for the same reason, zone reheaters are located as dose as possible to each zone. Where a reheater serves only one space, it is commonly located in the space. Table 1.... Design Conditions for Ships Area Outdoor Oes'go reraperafore* Heating Ventilating Coorng Indoor Coodriiottt DB & Effective Hit Living Quarters. Public Spaces... Naval Vessels.. F 0 0 +10 F F F% F 95 95 (DB) 80 50 73-74 80(WB) 95 95(DB) SO 55 73H-74M 80 (WB) 88(DB) 88 (DB) 85 50 75-78 80 (WB) 80 (WB) Combinations or variations of duct type and convection or radiant heaters are used, depending upon basic design requirements, such as weight and space limitations, and the economic justification of the cost of the type selected. Some design temperatures and humidities for various spaces aboard ship, are given in Table 1. The resulting quantities of air should be checked against typical heating and ventilation practices. for ships.* Living Spaces The minimum quantity of ventilation air provided for any sleeping or office space, inducting hospital space, should be based on a temperature rise over the outdoor air of not more than 10 deg (a rise of 7 deg is more satisfactory), with not less than 30 cfm per person! . In spaces fitted for eating, recreation, or manual work, the rise may be taken' at 10 deg with not less than 20 cfm per person. The same requirement applies to me chanical exhaust, although natural exhaust may be used - where only a short run of duct exists. Heat should be furnished to maintain the following tem peratures: . Staterooms, Berthing, Messing and Office Spaces. 70 F Working Spaces and Shops.....................................60 F Hospital Spaces........................................................ 75 to 78 F Machinery Spaces The prime purpose of machinery space ventilation is * to maintain a habitable temperature for the operating * 8m VeotiUtioa end of Maritime Commotion Ships, by J. W. Hariesrt (ffaotin# and Vtn&atiat, Feb. IMS, p. 233). Transportation Air Conditioning 669 personnel. It is more practicable to use spot cooling of personnel at working areas than to attempt to obtain uniform ambient temperature. The permissible tempera ture rise (above outdoors) at working stations is usually 15 deg, while the overall temperature rise is usually be tween 30 and 50 deg. These spaces must be exhausted adequately, preferably by mechanical means. Every attempt should be made to remove air at or dose to the heat sources. The capacity of the mechanical exhaust systems should be greater than the - supply, - taking into consideration the expansion of the supply air, to insure an indraft through access open ings to the space. Heat is not required for machinery spaces, except for those fitted with electrically operated equipment, which may remain inactive during periods while in port when heat ing to about 50 F will be required. Storerooms and Cargo Spaces The ventilation provided for these spaces depends on the type of vessel, location of space, and nature of cargo. Ventilation is required for all closed spaces. Even if ventilation is not necessary to preserve the stores or cargo, it is required to prevent the accumulation of toxic or combustible gases and odors. One air change in 15 to 30 min is common practice, except where inflammable liquids or proximity to hot spaces requires additional ventilation. Mechanical supply and natural erhant are usually used. However, where inflammahlfi gases may exist, natural supply and mechanical exhaust are provided. Many ships are fitted with dehnmiHificatinn facilities for eliminating damage to the dry cargo by preventing condensation and dampness. The dehumidification load consists of moisture removed from the ventilation air passed through the dehumidifier, plus the moisture on, or given off by, the cargo, packaging, dunnage, battens," and other materials in the ship's holds. The most severe outdoor condition requires a moisture removal of 90 grains (140-50) per pound of dry air, with 88 F cooling water. The largest cargo ships are provided with equipment for removing about 250 lb of water per hour. The dehumidifying systems generally utilize silica gel or lithium chloride with inhibitor.. (See Chapter 42.) In most cases central drying equipment is provided. On large passenger ships consideration..is given to the use of two dehumidifying units, because the cargo-carrying spaces are usually concentrated at the extreme ends of the vessel. A simple duct system distributes the dry air to the hold supply ventilation system. These ventilation systems use outdoor air when weather conditions are favorable. Re circulation and dehumidification are used only when neces sary, i.e., when the weather dew point approaches or ex ceeds the temperature in the hold. Two control stations are generally provided, one in machinery space and one in chart or wheeihouse. These stations are arranged so that either may change the cargo, conditioning system controls from use of outside air to use of conditioned air. AIR-CONDITIONED SPACE TREATMENT FOR SHIPS * The application of air conditioning to new American passenger ships is well established. All passenger state rooms, except steerage and third class, are usually air conditioned. This includes staterooms for ship's personnel and offices within conditioned passenger areas. Third class staterooms are air conditioned on some ships, de pending on the particular trade. Theaters, lounges, smok ing rooms, beauty shops, barber shops and similar closed public spaces are usually air conditioned. All messrooms, recreation rooms, officers' offices, crew's inboard rooms, and those having fixed porthghts are usu ally air conditioned on passenger vessels. The treatment depends on the requirements of the operator and the proposed itinerary of the vessel. SHIP SYSTEMS AND CONTROLS The types of comfort conditioning systems used to date generally have followed conventional lines, except for those serving staterooms, offices, and similar email spaces. Large public spaces are fitted with individual systems which supply dehumidified and cooled air during the cooling cycle, and warm air during the heating cycle. In many cases these rooms are fitted with large glass windows and doors, and require direct radiation to offset the downdraft which would occur in cold weather. Finnedtube radiation running the full length of the glam area -is commonly used for this purpose. Introduction of warm air at the sill, in lieu of direct radiation, is also used. Systems serving most public spaces are designed to provide all outdoor air as long as the refrigeration load is less than the capacity of the cooling equipment. Many central systems are simplified by using 100 percent out door air all-year-round. The important problem in ship air conditioning concerns the treatment of the gmA.ll spaces such as passenger staterooms, offices, and crew quarters. Low headroom, congested quarters, double berths, and unsymmetric arrangements mnJrp each space a problem in air distribution and treatment. The simplest system used for small spaces consists of a centra] filter hank, supply fan, preheater, and cooling and dehumidifying coil. The preheater steam valve and cooling coil water valve are controlled in sequence by a duct thermostat, in the fan discharge, set to maintain a constant outlet air temperature. Zone reheaters are pro vided to take care of variations in heating loads. The reheater steam valve is controlled by a submaster ther mostat at the reheater outlet. Control of room tempera ture is obtained by operating manual dampers in the air .supply to the space. A recirculation exhaust fan is fre quently provided, and operates in conjunction with auto matic dampers to utilize the maximum quantity of outdoor air consistent with capacity of the cooling coils. One system utilizes the same central supply equipment and recirculation exhaust system as the one just described, except that zone reheaters are replaced by individual space hot water reheaters. Each reheater is provided with a' control valve, controlled by room thermostat. Generally, a forced-circulation single-pipe hot water system is used. This system is generally used for staterooms and small spaces devoted to first and second claw* passengers. The average total air per person is about 60 cfm, and average outdoor air per person is about 18 cfm. A third system, used to a limited extent, is similar to the system just described, except that each room is pro vided with an induction unit (floor type where possible) which reheats the primary air supply. Control of heating coil in the induction unit is the same as noted for the system described in the previous paragraph. The average primary air supply is about 40 cfm per person. Recircuia- 670 . CHAPTER 48 1959 Guide tkm is not always used. The amount of induced air varies with unit design. A fourth less common arrangement is similar, but mnlrpg use of hot water in the induction unit in winter cold water in the induction unit in summer. Control of the valve on the unit is obtained by use of a summer-winter type thermostat. The unit is provided with' drip pan and drain piping to remove condensation. No recirculation is used. . On cargo ships, tankers and vessels not carrying pas sengers or not having air conditioning, heating of crews' spaces and officers' staterooms is usually obtained through a central system having filters, preheaters and reheaters. A minimum temperature of air leaving the preheater is controlled by a duct thermostat. The reheater is controlled by a sub-master discharge-duct thermostat, reset by out side master control. Relationship between submaster and master control (wherein discharge temperature is raised as outdoor temperature drops), is set according to a schedule based on the ship's itinerary. Ductwork for all systems described is designed for con ventional velocity. However, if power is available, and suit able duct construction and adequate sound absorbing facilities are provided, high velocity systems may be used. BIBLIOGRAPHY Koffawy PeiMaper Cora Report on Performance and Cost of Operation of 1937 In ternal Combustion Engine Mechanical Compression Equipment for Air Conditioning Railroad Passenger Cars (Division of Equipment Research, Amociatioa of American Railroads. May 1, 1937). . Report on Relative Performance of Air Filters (Mechanical Division, Association of American Railroads, January 15,1938). L. W. Wallace and G. G. Early, Jr.: Air conditioning of railroad passenger cars {ASMS Transactions, November 1937). Kenneth Cartwright: Pasenger car cooling methods (Re frigerating Engineering, February, p. 83; March, p. 158, 1936). J. R. Hornaday: Diesel drive for passenger air conditioning (Refrigerating Engineering, March 1942, p. 139). G. T. Wilson: Railroad air conditioning (Refrigerating En gineering, May 1943, p. 323). M. R. Eastin: Railway air conditioning (Railway Elec. Engr, August-Deeember 1942). F. L. Sahlmwnn and E. M. Bill: Head-end power for railway cars (Railway Elec. Engr, May 1939). J. D. Loftts: Head-End Power for Streamlined Passenger Trains (ASME Raleigh Section, October 26,1946). P.C.C. Car Ventilation (Westinghouse Electric Corp, B-3697, September 1946). . Bom end Avfooofofe* E. T. Todd and F. 0. Gadd: Bus heating (Heating and Ventilating, December 1946, p. 83). ' L. W. Child: Air conditioning of automobiles and buses (Society of Automotive Engineers Joxemal, June 1938). Jerry Hicke: Bus air conditioning (Heating, Piping and Air Conditioning, October 1938, p. 639). A. J. Mallinekrodt and Lars Hanson: Bus air conditioning (Refrigerating Engineering, June 1939, p. 388). O. G. Tinkey: What been done in auto air conditioning (Refrigerating Engineering, January 1953, p. 31). M. W. Baker, D. C. McCoy, H. V. Joyce, and P. J. Kent: Cars that beat the heat (Society of Automotive Engineers Jtntmal, July 1953, p. 19). P. J. Kent: Automobile air conditioning--progress and prob lems (ASHVE Transactions, Vol. 60,1954, p. 37). M. W. Baker and D. C. McCoy: Passenger automobiles (ASRE Air Conditioning Refrigerating Data Book, 1954-55, Chapter 50). D. W. Tomlinson: Comfort in high altitude flying (ASHVE Transactions, VoL 47, 1941, p. 57). A. J. Hess: Heat exchangers for aircraft (Refrigerating En gineering, September 1944, p. 192). B. M. Brad: Heating and ventilating for transport airplanes (ASHVE Transactions, Vol. 52, 1946). A. A. Amhym: Comfortisation of Aircraft (Pitman Publish ing Corp., New York, 1945). B. L. Messinger: Refrigeration - for air conditioning pres surised transport aircraft (Heating and Ventilating, January 1946, p. 63). ckip* Ventilation and air conditioning of the S. S. Panama (Heating and Ventilating, September 1939, p. 47). Air conditioning the new Mauretania (Heating, Piping and Air Conditioning, July 1939, p. 431). J. H. Clarke: Heating, ventilating and air conditioning on shipboard (Heating, Piping and Air Conditioning, August, p. 467^September, p. 529; October, p. 610, 1940). O. D. Colvin, W. H. E.` Hahne, and M. R. Colby: Care of cargo at sea (Society of Naval Architects and Marine Engineers Transactions, Part I, Vol. 46, 1938, p. 109; Part H, VoL 49, 1941, P- 208). Modem Marine Engineers Manual (Cornell Maritime Press, Cambridge, Maryland, 1943, Vol. il. Sections 16-19). Comdr. T. H. Urdahl, U.S.N.R, and W. C. Whittlesey: War ship ventilating, heating and air conditioning (ASHVE Trans actions, Vol. 49, 1943, p. 35). Comdr. R. H. Urdahl, U5.N.R, and W. C. Whittlesey: DeUSNJt.: Stamford hating and ventilating equipment for fighting ships (Heating, Piping and Air Conditioning, July 1943, p. 333). . Comdr. R. H. Urdhal, UB.N.R, and W. C. Whittlesey: De signing warship ventilation with standardised equipment (Heat ing, Piping and Air Conditioning, August 1943, p. 419). J. W. Markert: Modem air conditioning (Marine Engineer ing and Shipping Review, November 1945, p. 177). W. H. Carrier and L. E. Starr: Modem marine refrigeration and air conditioning (Marine Engineering and Shipping Re view, April 1946, p. 132). Capt. T. H. Urdahl and Comdr. E. R. Queer: Dehumidifica tion protects U. S. Navy's inactive fleet (Heating, Piping and Air Conditioning, March 1946, p. 71). Robert Tate: Reconversion of Liner S. S. Lurline (Society of Naval Architects and Marine Engineers, May 12, 1949). J. W. Markert: Air conditioning of P-2 American President liners (Pacific Marine Review, August 1946). J.-W. Markert: Export lines air conditioning of four yces (Marine Engineering, March 1949). CHAPTER 49 SNOW MELTING Design: Heating Requirement, Hydraulic Requirement, Installation: Safety, Internal Corrosion, Slab Construction, Thermal Stresses, Control, Testing, Draining, Drifting Snow, Design Example HE practicability of melting snow by means of heated the effects of these four factors, it is necessary to consider the Tcoils has been demonstrated in a large number of instal insulating effect of the snow before it is melted. As stated lations in sidewalks, roadways, ramps, and runways. In ad previously, the first ffokea fall on a dry, warm surface, and dition to eliminating the need for snow removal, other ad are then warmed to 32 F and melted. During the time that vantages gained are greater safety to pedestrians and vehicles, the flakes are bring wanned, and before they are completely and reduction of labor in removal of slush from floors. melted, they can be considered as tiny blankets or insulators. The design of a snow-melting system must determine and The effect of this insulation has been measured1 and nan be satisfy two primary requirements: (1) the heating require of considerable magnitude. Since the snowflakes cover a frac ment, and (2) the hydraulic requirement. Each of these is tion of the surface area, it has been convenient to think of treated in this chapter. Several points regarding installation the insulating effect as an area ratio. The area covered by the practices are also discussed. snowflakes is the insulated area, and the uncovered area is the DESIGN uninsulated area. The term free area ratio Ar has been adopted to represent the ratio of the uncovered, or free, area to the Heating Requirement total area or, The heating requirement for snow melting is affected by four atmospheric factors: (1) rate of snowfall; X2) air temper ature, (3) wind velocity, and (4) humidity. The effects of these - factors can be evaluated by consideration of the action of snow falling on a warmed surface. The first fall on a dry, warm surface, and are then' warmed to 32 F and melted. The water from the melted snow soon forms a film over the entire area and starts to evapo rate. The evaporation of the film is a mass transfer from the surface to the atmosphere. In addition, there is a heat transfer from the film to the ambient air and surfaces. Mass transfer due to evaporation. The rate of evaporation of the melted snow from the snow-melting slab is affected by the wind speed and the vapor-pressure difference between the air and the melted snow. The. vapor pressure of air, however, is fixed by the relative humidity and the temperature of the air. If the slab surface temperature is fixed, then the evapora tion loss varies with changes in air temperature, relative humidity, and wind speed. Heat transfer by convection and radiation from the melted snow to the ambient air and surfaces. A combined film coefficient has been used with sufficient accuracy to determine the com bined convection and radiation loss. This coefficient is based on a heat transfer from a ivetted surface, such as the film of melted snow, to air. The coefficient is a function of wind speed alone. The heat transfer, of course, is dependent upon tiie film coefficient and the temperature difference between the surface and the air. Since the surface temperature is fixed, tiie convection and radiation losses vary with changes in air temperature and wind speed. To determine evaporation and heat transfer from the melted snow to the air it is necessary to know three of the four climatic factors: (1) wind speed, (2) air temperature, and (3) relative humidity, and (4) rate of snowfall The fourth factor, rate of snowfall, is necessary to determine the heat required to warm the snow to 32 F, and to melt it. Before deriving equations to give quantitative values for Ar -- Free area ratio. A/ -- Free area, sq ft. A, -- Total area, aq ft. For At s 1, toe system would have to melt the snow so rapidly that the snow accumulation would be absolutely sero. This is impossible from a theoretical standpoint, but for all practical purposes it is permissible to have Ar = 1 as a max imum. For At -- 0, the surface would be completely covered with snow to a depth sufficient to completely prevent evapo ration and heat transfer losses. Research on the insulating effects of snow indicate that there are just three practical values for the free area ratio, 0,0.5, and l. This will be co^pred in greater detail in a later section. The equations for the heating requirements of a snow melting system have been derived and thoroughly explained in Reference 2. The general equation for slab output, q., as derived and discussed thoroughly in Reference 1, is ' <?. " g. + + Arty. + tfi) (2) where q, ~ sensible beat transferred to snow, Btu per (hour) (square foot). qm ** heat of fusion, Btu per (hour) (square foot). Ar " ratio of snow-free area to total area, dimensionless. q, = heat of evaporation, Btu per (hour) (square foot). ' 9k s beat transfer by convection and radiation, Btu per (hour) (square foot). 671 672 CHAPTER 49 1959 Guide Table 1.... Data for Determining Operating Characteristics of Snow-Melting Systems*'1 Period of No Saowfofl Period of SnowfafP Air Temperature, P Hour* of tnowfad* Required output, Btu per (sq ft) (hr)* Maxi muse Below Wind car Over 32 or equal to to to to to0 < to 50 too 150 200 250 300 350 to to output, Btu/ to 32 % of winter boors witfi no Meanduring freezing period* period,* mph Per- Hr per year J} 0 0 49 99 149 199 249 299 349 399 Frequency distribution of snowfsD hours at (sq ft) (hr) snow at above temperature* 1 Albuquerque, N. M.......... 74.7 Amarillo, Tex..................... 73.1 Boston, Mass...................... 64.6 Buffalo \xj v Niagara Falls/ '''' Burlington, Vt................... Caribou \w Limestone/ ........ 46.5 39.0 21.4 24.7 26.0 31.4 46.9' 54.5 70.6 28.2 24.6 24.7 8.5 0.6 22 /I \0 62.0 94.1 25.4 5.9 7.6 42 0.0 0.8 _ _ __ 259 82 13.3 0.9 33 /I to 33.7 88.1 35-4 15.4 10.7 10.1 1.8 3.0 1.8 -- -- -- 260 143 -14.2 4.0 145 /I \0 51.5 83.2 30.0 12.3 14.0 2.0 4.3 0.3 1.2 0.3 0.6 0.1 -- -- 0.1 -- 0..2 " 320 370* 23.9 19.6 16.5 10.8 6.6 240 /I \0 50.7 95.9 32.6 11.2 3.4 0.2 3.7 0.5 1.4 0.2 0.2 _ _ 309 192 10.8 6.5 236 \o 91.8 29.9 13.2 7.6 0.6 2.5 -- 0.6 -- 0.1 -- ---- -- -- -- -- 280 142 10.0 8.0 290 /I \o 35.0 92.0 39.7 16.0 7.5 0.5 5.7 -- 2.0 -- 1.0 0.5 0.1 __ ---- -- 378 138 Cheyenne, Wyo.................. 46.4 Chicago, HI..................... 45.4 Colorado SpringB, Colo... 54.3 49.8 50.9 43.6 21.5 21.4 22.1 Columbus, Ohio................ Detroit, Mich..................... Duluth, Minn..................... 59.0 47.0 12.6 38.1 49.3 80.5 24.5 24.1 14.5 Falmouth, Mass................. 68.5 Great Falls, Mont............. 49.0 Hartford, Conn.................. 66.4 29.5 46.2 38.9 25.5 16.5 24.4 Lineoln, Neb....................... 45.0 Memphis, Tenn.................. Minneapolis!*.- ,, st. puT 1"TM............. 87.2 23.6 52.5 12.5 70.8 20.8 27.0 16.9 15.3 11.5 11.5 3.8 138 3.7 134 2.1 76 fl \0 fl \o /I \0 10.0 10.6 12.0 2.9 105 3.7 134 6.9 250 /1 \0 (1 to /I to 12.8 14.4 8.2 2.0 73 jl \0 4.8 174 h \o 4.7 171 fl \0 10.1 . 2.5 91 11.5 0.3 11 11.1 5.6 203 /I \o fl to fl to 16.5 94.3 45.8 91.5 98.4 65.8 97.7 60.4 95.9 23.7 94.8 50.0 91.5 26.2 94.6 48.4 80.4 32.7 97.2 4S.4 85 0 28.4 96.5 26.2 5.4 37.4 8.1 36.3 .1.6 22.4 2.3 27.7 3.5 32.9 4.7 33.9 7.4 27.6 4.8 34.6 16.7 28.2 2.6 28.3 8.3 31.4 3.1 19.4 0,3 11.4 0.3 19.0 8.0 -- 9.3 0.6 20.6 0.0 14.2 1.1 16.7 0.6 11.2 2.2 20.0 0.0 6.7 6.7 21.7 0.3 13-1 -- 3.1 0.1 7.5 1.7 -- 1.5 -- 13.7 0.3 1.6 -- 16.4 __ 4.3 0.5 13.9 0.0 13.3 -- 14.1 0.1 8.6 4.7 4.2 -- ---- .1.4 0.6 0.2 -- ---- 4.4 5.5 0.5 _1.7 0.4 -- --, -- 0.8 0.3 -- -- -- -- 4 3 2.5 1.7 0.2 -- --'` 0.3 _ _ -- ---- 7.5 4.6 0.3 0.8 0.7 -- -- 0.1 -- _5.7 1.5 0.2 -- -- 3.3 -- -- -- ---- 3.5 0.6 0.3 -- ---- 4.7 2.6 499 -- -- 129 0.1 -- 368 -- -- 165 -- __ 311 63 __ 261 -- -- 72 -- -- 278 -- -- 140 O.61 __ 382 -- -- 206 _ 204 -- -- 144 0,5 0 ? 451 138 0.1 -- .396 0.1 -- 383 _ 293 -- -- 202 -- -- 227 -- -- 144 -- -- 313 -- " 155 Mt. Home, Idaho.............. 56.3 New York, N. Y................ 55.7 Ogden, Utah........................ 50.0 42.6 42.2 45.6 24.9 24.2 24.3 Oklahoma City, Okla..... 79.0 Philadelphia, Pa............. 75.8 Pittsburgh, Pa.................... 55.2 19.8 22!6 39.8 24.6 26.7 24.3 (09.5 11.8 1.1 2.1 40 76 fl 74.2 21.9 3,9 143 1 98.1 53.1 1.9 31.8 9.4 2.2 1.6 1.7 -- O.i -- 90 385 87.6 9.6 1.5 0.7 0.3 0.3 -- -- -- 298 9.4 4.4 160 fl to 64.6 88.8 29.2 9.4 5.8 1.4 0.3 0.3 0.1 0.1 -- -- -- -- -- -- -- -- 216 216* 15.8 1.2 44 /I to 27.8 95.7 18.7 17.0 12.6 14.3 4.3 5.9 2.7 1.0 _ 394 81 9.7 1.6 58 fl to 62.3 84.3 23.6 10.4 2 3 0.9 14.0 1.1 0.2 0.4 0.5 -- -- -- 296 -- -- -- -- 229 11.6 5.0 182 fl to 53.6 93.3 30.8 5.9 8.4 4.6 0.7 0.1 1.9 0.7 -- -- "-- -- -- -- 282 157 Portland, Ore...................... 92.9 Rapid City,' S. D............... 45.2 Reno, Nev............................ 56.0 6.1 51.6, 41.6 28.9 19.3 24.3 8.4 _12.9 1.0 36 3.2 116 /I 1 io 78.0 91.5 29.7 97.6 16.9 5.1 8.5 29.0 16.0 2.2 0.2 8.4 6.3 -- 125 3.6 l. 2.C 3.1 681 -- -- -- -- 102 _-- --5.6 2.4 87 fl to 82.6 90.2 15.4 8.0 1.8 1.6 0.2 0.2 -- -- -- -- 152 -- -- -- 154* Snow Melting . Table 1 ....Data for determining Operating Characteristics of Snow-Melting Systems*' 1 (Conducted) 673 > The period covered by this table is from No. 1 to March II, ind. with February takes as a Ifljf day month. Total hours in period " 1830. * The percentage is Columns 3 and 3 plus the percent under boun of snowfall total 100 percent. Note that Hovrt aj Snetc/aC does not isdode idling time, and is not actual operatic* time. See text. * Snowfalls ol trace amounts are notincluded; bcnce, Ho*rftSnow/oll meladesonly thcee hours of 0.01 inches water equivalent per boor anowfalL * Out put does not include allowance for beek or edge losses thcee depend on slab construction. * Percentages total 100 percent at the number of hours at snowfall, Prssitae Period is thst during No Snowfall when the air temperature is S3 F or below. * When heatoutput for Ar " 0 equals or exceeds the heat output for A, -- 1, the heat transfer qi i*^osi tbs air to the slab. This occurs when snowfall is at temperatures above 32 F. . The sensible heat, q,, to raise the temperature of the snow to 32 F is q. - 2.6a (32 - i.) ' (3) where " a = rate of snowfall, inches of water equivalent per hour, f# = air temperature, Fahrenheit. The heat of fusion, qm , to melt the snow is qm = 746a (4) The heat of evaporation, q., (mass transfer) is q. = A^(0.0201ti + 0ld55)(0.185 - p)ir (5) where hj, -- heat of evaporation at the film temperature, Btu per pound. - v -- wind speed, miles per hour. pn = vapor pressure of moist air, inches of mercury. The heat transfer, , (convection and radiation) is where g ~ 11.4(0.0201v + 0.055)(f/ - U)At (6) (/ *= water film temperature, Fahrenheit. In addition to determining the four hating requirements, it is necessary to make allowance-for back and edge losses. These losses vary from 30 to 50 percent, depending upon the slab construction and fluid temperature. The equation for the required fluid temperature to provide an output q9 has been derived in Reference 2. For construc tion similar to.Fig. 1, the equation is f. - 0.5g* + f, , (7) where . t,, = mean fluid temperature (antifreeze solution), Fahrenheit. Equation 7 will apply to 1 in. as well as in. IPS pipe-- see Fig. 1. Equations 2 to 7 permit the designer to determine the heating requirement of a snow-melting system. The solutions of these equations, however, require the eimvitaneoue con sideration of the four climatic factors: (1) wind speed, (2) air temperature, (3) relative humidity, and (4) rate of snowfall. It is not satisfactory to use annual averages or maximums for the climatic factors. If averages or maYimums are used there is no assurance that they will ever occur simultaneously. It is necessary, therefore, to make a frequency analysis of the solutions to Equation 2 for all the occurrences of snowfall for a period of several years. Such an analysis for 33 cities appears in Table 1 which contains the operating information for a snow-melting system. For freeting temperatures (32 F and below) without snowfall the system may be idling which means that some heat is supplied to the slab so that there will be immediate melting when snow starts to fall. Column 4 of Table 1 gives the average temperature during freeling periods. This temperature is used in calculating .the idling load. The other term needed to calculate idling load is the wind speed during the period of,freezing temperatures. The column, Hours of Snowfall, indicates the. number of hours that snow is falling at rates equal to or greater than 0.01 in. of water equivalent per hour. There are snowfalls of X 674 CHAPTER 49 1959 Guide Table 3... .Design Data for Three Casses of Snow-Melting System* caaaete). Fig. 1 .... Detail of Snow Melting Panel trace quantities about twice as often as there are for meas urable quantities of 0.01 in. or more. It is assumed that these light falls can be handled by the idling load. The remaining columns of Table 1 represent the frequency distribution of required heat output. This distribution is based on the solution to the basic equation for two values of the free area ratio, Ar . This distribution represents the haiw of the analysis and is also the for Tables 3 and 4. For specific conditions, or for cities other than those given in Table 1, the solutions to Equation 2 are given in Table 2. Table 2....Heat Output and Fluid Temperature for Snow-Melting System Cute of K Snowfall f. - OF i. = 10 F f. = 20 f fa - SO F Speed V Speed Speed - Spee< 5 10 15 5 10 15 5 10 15 5 10 15 0.08 1.0 9 151 205 260 127 168 209 102 128 154 75 '84 94 tm 108 135 162 97 117 138 85 97 110 70 75 79 0.0 9. 66 66 66 64 64 64 62 62 62 60 60 60 tm 66 '66 66 65 65 65 64 64 64 63 63 63 0.16 1.0 ? 218 273 327 183 233 274 165 191 217 135 144 154 tm 142 169 198 129 149 170 117 129 142 100 105 109 0.0 4. 133 133 133 129 129 129 125 125 125 121 121 121 tm 99 99 99 97 97 97 95 95 95 93 93 93 0.25 1.0 7. 292 347 401 265 305 346 235 281 287 203 212 221 tm 179 206 234 165 186 206 151 163 176 134 139 144 0.0 9. ^06 208 208 202 202 202 195 195 195 188 188 188 tm 137 137 137 134 134 134 131 131 131 127 127 127 Not*: Tbit table is baeod an relative humidity of SO percent far til sir tem- penture*. ' * " rmto of siowitll, taebo* of water equivalent per hour. At tree area ratio. . ( -- dab output, Bta pm (boor) (aquare foot). U air temperature, Fahrenheit. tm - Said temperature.Fthrcabeit.BasedaoeoastruetioeaaabowiiinFig.1. * " wind speed, milee per boor. cay Albuquerque, N. M. Amarillo, Tex. Boston, Mass. Buffalo-Niagara Falla, N. Y. Burlington, Vt. Caribou-Limestone, Me. Cheyenne, Wyo. Chicago, III. Colorado Springs, Colo. Columbus, Ohio Detroit, Mich. Duluth, Minn. . Falmouth, Mass. Great Falls, Mont. Hartford, Conn. ' Lincoln, Neb. Memphis, Texrn.' Minneapolis-St. Paul, Minn. Mt. Home, Idaho New York, N. Y. Ogden, Utah Oklahoma City, Okla. Philadelphia, Pa. Pittsburgh, Pa. Portland, Ore. Rapid City, S. D. Reno, Nev. St. Louis, Mo. Salina, Han. Sault Ste. Marie, Mich. Seattle-Tacoma, Wash. Spokane, Wash. Washington, D. C. Oewpo Oifpef, Bftr per (Hr) (Sq Ff) Ckm 1 system1 Ckm 0 Ckm IB system2 system* 71 82 167 98 143 241 107 231 255 80 192 307 90 142 244 89 (93) 83 89 49 (63) 52 138 129 165 63 72 307 425 350 293 253 69 83 (114) 93 84 (112) 115 140 206 144 138 254 255 374 165 372 260 64 (67) 134 63 (95) 50 121 202 144 155 90 298 246 212 254 140 342 98 216 217 66 81 350 97 229 263 89 157 275 86 97 111 58 (86) 98 122 85 52 (78) 102 154 152 120 144 447 155 198 228 213 92 128 133 87 127 189 117 121 144 From Atr Conditioning, Heating and VenlUaiing, August 1957, p. 92. * Where idling rate is greater than Class I design rate, idling rate is given in parenthesis and should be used as Class I design output. ' 1 Po Class I (residential) Bytems, tbe design output is mt at that required beat output (see Table t) when Ar * 0 at tbe Uth p--of tbe frequency djetributkm; that b where $8% of tbe hours bare this outputor tea. * For dear U (oommeraal) System*, tbe put when At " 0 fa Table 1 Qast column). output is ' maximum out * For Class QX (industrial) Systems tbe design output it determined by tbe faQowing four requiieinente: (1) Output a never nrnmtod for two eouseeutive hours; (S) Output far Ar m 1; Table 1, bat least 1 Btu pa hour per eq ft greater than maximum output far A, -- 0; (2) A, b greater cr equal to 0A maxi mum requirement shown fa Tabb 1 far Ar -- 1. That b, + + OJ (s + gt) far tbe eonditioca where ?i " , + $ + O + 9, ere a maximum; (4) The free area rstao At a unity for at least 88% of tbe hours Deted in Table 1. Snow Melting 675 Table A .... Yearly Operating Data UEag ' Mefttng Idling AWfmg Cy Kate,* Dutpvt,* Out- aty Rote,* Output,* Tone,* Owt- hr per Its per year (sq ft) Uq H) Class* (year) (sq ft) hr per (w" (year) hr per Quo* Btu per (yer) 1*0 fi) Uqft) (sq ft) Albuquerque, N. M... 897 32.5 29100 944 51.1 48200 1140 52.1 N. Y........................... 1702 50.2 85500 *> 6 i 1978 76.9 152000 93.0 238000 77.7 140000 1848 67.8 125000 1583 63.4 100000 1383 45.0 22 33 145 240 290 138 134 76 iojP , 908 u 969 Mt. Home, Idaho.... 1546 TTT 1150 I 2150 11 2520 New York, N. Y........ 1532 m 2770 8000 II 1655 in 9100 i 11800 i 14600 Oklahoma City, Okla. 719 in 14900 i 11800 u 820 in 13800 i 17800* i 20600 1445 m 22500 i 9730 221 TIT 20200 i 7200 ii 8390 Rapid City, S. D.... 1873 Til 8700 1 3960* II 3960 1510 III 7390 1 3590 II 4180 III 5350 I 5540 1104 41.9 64300 50.7 77700 44.6 56.2 40400 31.4 25700 49.5 71500 17.4 3840 86.4 162000 36.9 55700 44.8 4950 40 76 44 58 182 36 116 87 33 I 1260 11 1530 III 1590 1 4180 11 4690 111 4710 I 7050 TI 111 7370 I 2380 II 2800 111 5400 I 2710 TI 3100 111 3110 I 9050 11 10700 111 11100 1300 IT 1330 111 1360 1 7450* U 8250 111 13400 1 2970 n 3030 in 3030 i 2190 TI 2290 111 2380 I 2920 TVilntli M" w ' .' 2922 113.8 332000 250 1071 44.2 47400 73 1677 111.6 187000 174 1412 59200 171 1906 67.2 128000 91 454 32.0 14500 Minneapolis-St. Paul, 2570 95.1 244000 11 203 III 1 III I III I III I 11 III I IT III I II III 1 II III 7070 33200* 39500 3830 4290 13700* 15400 19100 9830 10800 10810 4750* 8350 8520 702 721 792 14200 17600 18400 Sault Ste. Marie, 2512 77.7 195000 Seattle-Tacoma, 392 17.2 6750 345 44 1673 39.1 65500 196 Washington, D. C... 770 30.6 23600 33 III 3810 17600* M 22200 111 23200 1 1410 11 1430 III 1430 1 8650 TI 9350 IU 9560 I 1650 II 1660 111 1690 * Rat* when idling, Bta per (Hr) (Sq Ft) - (QJ7 -f S4) (S3 - 0.' here* TM wind speed from Column 5, Table 1, ead . -- air temperature from Column 4, 1 Product of tbe two preceding column*. Hour* of Snowfall, from Column 7, Table 1. Based on tbecondition that surface temperature ii maintained atS3 deg until required output exceeds designed output, at which time design output a used rprftlfM of required output. Distribution of required output based oo Table 1. Based on Idling Bate rather than Design Rate. Atr Conditioning, Heating and Ventilating, August 1957, p. 94. Notice that these solutions are for a relative humidity of 80 percent. For other values of relative humidity, corrections be obtained by using Equations 8 and 9 as follows; aq -A-(0.0201p + 0-055)^, dp. (8) (0.0201, + O.OSSM,, (9) Snow-melting installations are classified in Table 3 ac cording to types as Class 1, II, or III. These classes have been dismsaBd thoroughly in Reference 3, and are defined in pcerasarawsss 676 CHAPTER 49 1959 Guide the footnotes to Table 3. Briefly, snow-melting systems are classified as to the urgency for melting as follows: Class I (minimum): Residential walks or driveways and interplant areaways- Class 11 (moderate): Commercial (stores and offices) side walks and driveways, and steps of hospitals. Class III (maximum): Toll plazas of highways and bridges, and aprons and loading areas of airports. These classifications depend upon the allowable rate of snow melting. For example, a residential system does not have to melt snow as rapidly as a commercial system. In fact, a depth of snow of an inch, for an hour or so during a heavy storm might not be objectionable with a residential system. On the other hand, a store manager would consider tiie system inadequate if half an inch of snow accumulated on the sidewalk in front of the store. The difference, then, between a Class I system and a Class II system is in the required ability of each system to melt snow. The one feature that is common to' all classes is that the systems must be adequate for some combination of weather factors. The designer may select equipment having capacity to melt snow whenever conditions are milder than some critical values, but be willing to have an inadequate system for a given fraction of the time. In other words, the designer will take a calculated risk providing he knows the odds of that risk. For a residential system, where initial cost must be at a minimprn. the designer must accept more frequent snow accumulations. Table 3 contains the design heat requirements for the 3 classes of snow-melting systems. Under Class I systems, the values in parentheses are idling rates and, since they exceed the Class I design rates, should be taken as design output for this classification. Design rates may be altered by the de signer if he feels that a particular job should have different design criteria from those given in the footnotes of Table 3. Any change in design conditions used should bebased on the frequency distribution given in Table 1. Use of Tables 1, 3, and 4 is illustrated by Example l. Example t: An engineer has been retained to design snow melting systems for the service areas of a turnpike running from the eastern edge of the Wisconsin-Illinois border north west to the Wisconsm-Minnesota border just east of St. Paul. He decides that Chicago data wifi be adequate for the southern terminus and that Minneapolis-St. Paul data will be adequate for the northern terminus. Hio problem is to determine the heat and hydraulic requirements of the systems for service areas between Chicago and St. Paul. Solution: Assume, for this example, that the city in question is Madison, Wis. Weather bureau records indicate tnat the annual average number of days with snow cover of an inch or more would be 100, and that the engineer assume an aver age snowfall of 40 inches. In addition, he can estimate about 11 days per year with a snowfall of an inch or more (see Refer ence 3) For the walkways to the restaurant from the parking area a Class I design rate could be used. This rate could be taken as 90 Btuh per sq ft. This is in good agreement with'data in Tables 3 and 4 which give the rate at 89 (design rate) for Chicago and 95 (idling rate) for.Minneapolis. ' The lanes leading from the turnpike to the gasoline pumps and parking areas should be rated as Class II areas. A check of Tables 1 and 3 would indicate that 160 Btuh per sq ft would be adequate. If an emergency area were included, for a wrecking truck, ambulance, or police garage, it would be wise to consider a Class III rate for such areas. An inspection of Table 1 for Chicago shows that a rate of 275 Btuh per sq ft would be ade- Table 5 .... Physical Properties of Antifreeze Solutions* Fhkl Ethylene Glycol 15.3%byvol. . Ethylene Glycol 31.4% by vol.- Ethylene Glycol 42.7% by vol. Ethylene Glycol 51.2% by vol. Heat Transfer Oil freezing Profectron Temp. F +20 0 -20 -40 * -40 Water ` +32 * B>aed on data given in Reference #, r -- Kinematic riaeceitjr, (feet squared per second) Hem * X 10` c` w p X 10* e to p X 10* c to -20 _ -- -- -- -- -- _ -- " FfafcJ Temperature--Fdireflfieit 0 20 40 120 140 160 200 __ 2.64 0.840 0.687 0.577 0.45S -- -- 0.935 0.956 0.960 0.962 0.969 -- -- 64.0 62.8 62.5 62.1 58.8 _ 6.86 4.18 1.19 0.955 0.784 0.609 -- 0.833 0.850 0.895 0.905 0.910 0.923 -- 65.7 65.4 64.1 63.7 63.3 60.0 16.1 0.764 66.8 9.47 0.775 66.7 5.75 0.788 66.3 1.46 0.832 65.3 1.20 0.845 64.9 0.950 0.856 64.4 0.748 0.884 60.6 X 10* c to 46.3 0.682 68.2 21.3 0.717 67.6 12.13 0.726 67.4 7.54 0.745 67.2 1.77 0.809 65.9 1.46 0.823 65.4 1.14 0.835 65.0 0.870 0.854 61.1 * X 10* c to X 10* c to 105 0.382 62.9 -- -- -- 43.1 29.7 0.390 - 0.400 62.5 62.0 _ ---- ---- 14.0 0.408 61.6 1.71 1.005 62.4 3.13 0.444 59.1 0.603 0.999 61.7 2.51 . 2.06 0.452 0.462 58.6 57.6 0.494 0.999 61.4 0.413 1.001 61.0 1.48 0.480 55.3 0.328 1.005 60.1 for oO at 10 F, v -- 0X00140 ft* per eec.). e -- specific beat, Btu per (pound) (Fahrenheit degree), w.-- specific weight, pounds per cubic foot. Snow Melting 677 quate for A, - 1 for 99.4 percent of the time- Similarly, 275 would be adequate 99.4 percent of the time in St. Paul. There fore, 275 Btub per sq it sufficient for the emergency areas. Table 3 in Class III column lists 350 Btuh per sq ft for Chicago and 254 for St. Paul but for uses similar to the areas in this example, 275 should be adequate. Hydraulic Requirement After determining the heating requirements, it is necessary to determine the hydraulic requirements of the system. This can be done by means of the procedures explained in Chapter 4, Fluid Flow, but it is necessary to use the proper physical properties of the antifreeze solution. A complete discussion of tiie hydraulic problem is given in Reference 4. The main consideration is the proper allowance for vis cosity. Table 5 gives viscosities for typical fluids used as Table 6 .... Conversion of Kinematic Viscosity Units* Cenfcfoke* (H/Seel X 10* ssu>> Cenfatofces (H*/See) X 10* SSU** 2 2.15 32.6 31 33.4 145.7 2.5 2.69 36.0 32 34.4 150.2 3 3.23 36.0 33 35.5 154.7 3.5 3.77 37.6 34 36.6 159.2 4 4.30 39.1 35 37.7 163.7 4.5 4.84 40.8 5 5.38 42.4 6 6-46 45.6 36 38.7 168.2 7 7.53 48.8 37 39.8 172.7 8 8.61 52.1 38 40.9 177.3 9 9.68 55.5 39 42.0 181-8 10 10.8 58.9 40 43.0 186.3 11 11.8 62.4 41 44.1 190.8 12 12.9 66.0 42 45.2 195,3- 13 14.0 69.8 43 46.3 199.8 14 15.1 73.6 44 47-3 204.4 15 16.1 77.4 45 48.4 209.1- antifreezes for snow-melting systems. Viscosities are given in feet squared per second. Table 6 can be used in conversion of viscosity units. A large increase in viscosity will be noted for glycols and oils--about 20 times--as the fluid temperature changes from 160 F to 0 F. This viscosity change has two effects. First, an increase in viscosity mil increase the fluid friction in the piping circuit. Second, an increase in viscosity will decrease the pump capacity--in both volume and head. The effect of viscosity on fluid friction in the piping circuit is illustrated in Fig. 2. For large installation, the friction losses should be cal culated by the Fanning equation where ' h, -- the loes in head of the fluid under conditions of flow, in feet. I -- the length of the pipe, in feet. V " the velocity, in feet per second. g TM the acceleration due to gravity = 32.174 ft per (second) (second). D " the internal diameter of the pipe in feet. ' / = a dimensionless friction coefficient which can be de termined from Ftg. 4, Chapter 4. The Reynolds num ber can be computed from data in Table 5 of this chap ter. ' Solutions for the pipe friction should be plotted for tem peratures at the starting condition (probably 0 F) and at the operating condition (use either 120 or 160 F). Then on the snmft graph, the operating curve of the pump should be plotted (see Reference 4 for such a graph). The intersection of the fluid friction curve and pump operating curve will give the operating point for the system. Table 7 can be used to allow for the viscosity effect on the pump. The designer must decide on the tolerable viscosity limit. Generally it is between 300 and 500 SSU, although for 16 17.2 81.3 46 49.5 213.7 17 18.3 85.3 47 50.6 218.3 18 19.4- 89.4 48 51-6 222.9 19 20.4 93.6 49 52.7 227.5 20 21.5 97.8 ' 50 53.8 232.1 21 22.6 102.0 55 59.2 255.2 . 22 23.7 106.4 ... 60 64.6 278.3 23 24.7 110.7 65 69.9 301.4 24 25.8 115.0 70 75.3 324.4 25 26.9 119.3 26 28.0 123.7 27 29.1 128.1 28 30.1 132.5 29 31.2 136.9 30 32.3 141.3 Oto- 704) ccatfetokn, SSU - 4.S3S X ceatistok**. * Kinematic vbcasitjr In ftV*ec m 1X76 X 10 X eentotokeab Value* lilted for 8SU (S7bolt Second*--Univenal) are for fluid tempera* tore* of 100 F. To obtain the Saybolt Universal vaooeitjr equivalent to a kine matic vfeaoeity determiimd at a Fahrenheit temperature (, multiply the equiva lent Saybolt Universal vieooeity at 100 F by .1 + (1 -- 100) 04)00064; for example, 10 eentfetoke* at 210 Fareequivalent to MX X 1X070 or $94 eec Saybolt Universal at 110 F. (Taken from ASTU D 44$ - 61).._ - (For J-tn. Pipe) Rg. 2 .... Effect of Viscosity on Friction Lo 678 CHAPTER 49 1959 Guide Table 7 .... Viscosity Effect on Centrifugal Pump Characteristics Kimootic Vhcostj SSIP Correction Factor* Pump Head Pitnp Capacity Pemp Efficiency 0 to 30 50 100 200 1.00 1.00 0.98 0.96 1.00 1.00 1.00 % 0.98 1.00 0.94 0.88 0.79 300 0.95 0.97 0.73 400 0.93 0.96 0.68 500 0.92 0.96 0.65 600 0.91 . 0.95 0.62 700 800 900 1000 0.90 0.89 0.88 0.87 * SSU 8yt>oit Seconds--OumnL 0.94 0.94 0.93 0.92 0.59 0.57 0.55 0.53 Table 8 .... Correction Factors for Pipe Size (For laminar Ftow N& < 2000) Pip* Sire inside Diameter lnd>es Feet D,-4 Ft* ,, 5-84 X KT o,4 (See figvre 2) ' M 0.622 0.0518 7.18 X l<r 8.13 y* 0.824 0.0687 2.23 X 10-` 2.62 i 1.049 0.0874 5.84 X KT* 1.00 IH 1.380 0.115 1.75 X 10-4 0.334 1M 1.610 0.134 3.26 X 10" 0.179 2 2.067 0.172 8.75 X 10-4 . 0.0667 2H 2.469 0.206 1.81 X 10-* 0.0322 3 3.068 0.256 4.30 X 10" 0.0136 3* 3.548 0.296 7.68 X 10"* 0.00760 4 4.026 0.335 1.26 X I0"* 0.00462 5 5.047 0.421 3.14 X 10-* 0.00186 6 6.065 0.505 6 50 X icr* 0.000898 commercial or private systems (where A, is 0-5 or 0) it may go to 750 SSU. Efficiency loss is not important, but head and capacity losses are. Reduced flow means a longer period of time for the system to become operative from a- cold start. The viscosity limit is controlled by means of a low-limit thermostat. For example, if it is desired to hold the viscosity of the solution to less than 200 SSU (43.1 ft sq per sec), then lor the oil shown in Table 5, the low-limit control would be set at 0 F. For umall jrtftjJla.tmnq, a quick method of determining the fluid friction for a 1-in. IPS pipe circuit is given in Fig. 2. - The required pump capacity, in pounds of fluid per hour is given by the equation: ' Arft C CmAi (U) when ' C = pump capacity, pounds per hour. Af " area of slab, square feet. fi - total heat requirement (slab output, q,, plus back and edge losses) Btu per (hour) (square foot). c -- specific heat at temperature , Btu per (pound) (Fahrenheit degree). At " temperature drop through circuit, Fahrenheit degress. For a temperature drop ofAf = 20 F, Equation 11 becomes G------- hlLHSOtCbCo (12) where ' O -- gallons per minute. uu " mean specific weight at temperature tm , pounds per cubic foot. ' An approximate solution for systems using pipe rises other than 1-in. IPS can be obtained by using Table 8 or Fig. 3. Table 8 is for use when the flow is in the laminar sone. Fig. 3 is for flow in the turbulent sone. For flows where Reynolds number Mis between 2000 and 3000, no reliable prediction for pressure loss can be made. It is generally safe.to assume the flow to be increased to a Reynolds number of 3000 with the pressure loss estimated at that flow rate. Figure 2 is based on a pipe rise of 1 in. IPS. If another pipe size is used and the flow is laminar, the correction factor K from Table 8 can be used. For example, assume a viscosity of 300 SSU, a flow of 5 gpm, and a K-in. IPS pipe. Fig. 2 shows that for 1-in. IPS, friction loss would be 15.50 ft/100 ft. Table 8 gives K = 2.62 for K-in. pipe; therefore, friction km would be 15.5 X 2.62 = 40.6 ft/100 ft. If the flow is in the transition zone or is turbulent, then Fig. 5 of Chapter 28 can be used in conjunction with Fig. 3. For example, assume a viscosity of 0.0001 sq ft/sec (56.5 SSU), a flow rate of 14 gpm and a 1M-in. IPS pipe rise. .(For Ng > 3000) (Acsod oa data girea in Reference 6) Fig. 3 .... Friction Correction Factor for Viscosity Snow Melting 679 Fig. 5, Chapter 28, shows a head km for water to be 190 mihnches per foot or 1.58 ft/100 ft. Fig. 3 gives a correction factor K of 1.75 for a viscosity of 0.0001 sq ft/sec; henoe, the pressure loss is 1.58 X 1.75 = 2.77 ft/100 ft. INSTALLATION There are certain precautions that must be taken during installation. They concern internal corrosion, flammability, toxicity, cleaning, joints, and hookup. A comprehensive discussion of these precautions may be found in Reference 5. Safety . Since ethylene glycol and petroleum HistilUtAn are slightly toxic, the system should be installed and maintainpH in dependently. There should be no permanent connection between the snow-melting system and the drinking water supply. . Ethylene glycol is not considered flammable. In fact, aqueous solutions of less than 60 percent glycol are used for fire sprinkler systems. These solutions do not freeze, and they are effective fire extinguishing agents. Petroleum distillates suitable for fluids in snow-melting systems are classified as non-flammable, but have fire points between 300 and 350 F. When using fluids of thin type, care should be taken to collect any oil dripping from the seal* on the pump. It is good practice also to provide some barrier between the oil lines and the boiler so that in the event of a leak, a flash back from the boiler will not ignite, the oiL There are other non-flammable fluids, such as those used in some transformers, that can be used as the antifreeze. These fluids are three or four times as expensive as the glycols or oils, but combine the fire protection of the glycols with the corrosion protection of the oils. Internal Corrosion Ethylene glycol solutions tend to become corrosive in service; therefore, rust inhibitors are generally included. Even with an inhibitor, the solution should be tested annually to determine any change in acidity. If the test indicates that tile inhibitor has been exhausted, the entire system should be drained and a fresh solution installed. To increase the life of the inhibitor, the heat exchanger surfaces should be kept below 285 F which corresponds to about 40 prig steam. Temperatures above 300 F accelerate the deterioration of the inhibitors. Slab Construction It has been found satisfactory to use J$-in pipe or tube on 12-in. centers as a standard coil. If pumping loads re quire a reduction in friction the pipe size may be increased to 1-in., but the slab depth must be increased accordingly. The piping should be supported in such a manner font there is a minimum of 2 in. of concrete above and below the pipe. This requires a 5-in. slab for 5i-in. pipe and 5%-in. for 1-in. pipe. - If an insulating material is used beneath the structural slab, it is generally good practice to provide a moisture hamer between the insulation mid the fill. A roofing material (such as a 55 lb felt) is often used as a moisture barrier. The joints in the barrier should be mopped, and the fill mad* smooth enough so that there will be no holes or gaps for moisture transfer. Also, the. edges of the barrier ahnnlH be flashed to the surface of the slab so that the ends are sealed, If the pipe must pass through an expansion joint, a pro tective coating should be applied to the pipe for a foot or two on both rides of the joint. If the pipe is kept dry at all times in both summer and winter, no external corrosion problems will occur. Thermal Stresses This problem is discussed in Reference 7. In general, there will be no ill effects from the thermal stresses if these rules of installation and operation are followed: 1. Keep the temperature difference between the fluid and the slab surface to a minimum by.: a. Close pipe spacing (see Fig. 1). b. Low temperature drop in fluid, At < 20 F deg. - c. Continuous operation (if economically feasible). 2. Keep pipe near surface to obtain about 2 in. cover. 3. Use reinforcing steel designed for thermal stress if high structural loads are expected (such as on highways). Control Normally snow-melting systems are manually controlled. They are started by an operator when snow is anticipated or is falling, and they are shut off when the snow has stopped falling and the area is clear. This is strictly two-position control either 0 or 100 percent operation. One version, with some degree of control, provides a surface-temperature control. The system is started manually, as before, but a thermostat controls the heat input to maintain & surface temperature of approximately 33 F. There are several fully automatic control systems, how ever. In general, these systems provide some means of detecting precipitation and simultaneously waging air temperature. One method is to set a thermostat for a 35 F air temperature and arrange to have the signal from this . thermostat activate a heating element on a receptacle. This ... warm receptacle collects tire precipitation, and melts it if it is frozen. The water then runs through a tube and activates another circuit. This second circuit can be used to start the snow-melting system. Another thermostat can be used to control tiie surface temperature of the snow-melting slab. For baric information on control equipment, such as thermostats, and for fundamentals of control circuits, see Chapter 43. Testing . After installation and before pouring concrete, all piping should be tested to about 100 psig. This pressure should be maintained until all welds and connections have been checked for leaks. If an oil is used as an antifreeze, the test should be performed with air or some gas (only 50 psi required with an air test) but not with water. The danger of using water is that the pipe may not be thoroughly dried when the oil is intro duced. The water will tend to collect, and when the tempera ture falls below 32 F the collected water may freeze and cause damage. Draining Proper drainage is necessary for both the slab surface and the coil. The slab must be sloped so that the water from the melted snow can run off. Puddles are objectionable on sidewalks or drives. They cause splashing, and they retard heat flow from the embedded pipes. The pipes must be placed so that they may be drained. If tiie antifreeze becomes corrosive it must be drained. It is not 680 CHAPTER 49 1959 Guide good practice to rely entirely on blowing of air through the system. Drifting Snow It is quite likely that some drifting will occur on every system that is adjacent to a wall or vertical surface. The designer should try to anticipate this condition and add extra piping in these areas. 0 possible, coils should be added in the vertical surface. Another expedient is to carry the drainage to the area expected to be drifted. The drainage will tend to wash away some of the snow. Design Example . Example t: Assume that there are three independent hy draulic systems to be used in the snow-melting application described in Example 1. One.system will be for the Class I area, another for the Class II, and the third for the emergency area, or Class HI area. . Determine the hydraulic requirement for the Class II sys tem, assuming an area of 100,000 sq ft. Solution: The beating requirement has been determined as 160 Btuh per sq ft. Since an area of this type has a large per imeter, nmo the edge and back losses add about 40 percent or 64 Btu per sq ft. The total heat requirement, then, will be taken as 224 Btuh per sq ft or 22.4 X 10* Btuh lor the 100,000 sq ft area. The fluid temperature is determined by using Equation 7: v - 0.5 q. + t, 8inee q, -- 160 Btuh per sq ft, and tf * 33 F - - 0.6 X 160 + 33 - 113 F. If an oil antifreeze is used, the specifics heat, & , the kine matic viscosity r. , and the specific weight tow , at 113 F can be found by interpolation in Table 5 as Cm ~ 0.440 Btu per (lb) (F deg) " 3.88 X 10"* sq ft per sec. - An accurate determination of viscosity cannot be made by interpolation in Table 5 and should therefore be made by use of ASTM Standard Viscosity Chari B. to. a 59.4 lb per cu ft Then from Equation 12 al&hOmCm 10* X 225 160 x 59.4 x 0.440 5380 gpm Equation 12 is based on a temperature drop of 20 F deg, therefore, the fluid must enter the slab at 123 F and leave at 103 F in order to have the desired mean temperature of 113 F. Assume that the coil with the longest equivalent length is 300 ft and has a flow of 12 gpm. Such an arrangement would suggest the use of a coil of 1 in. IPS- From Table 1, Chapter 31, theXD -- 1.049 in. = 0.0875 ft which gives an internal cross sectional area of 0.00600 sq ft. For 12 gpm the flow is 0.0268 cu ft per sec and the velocity is 0,0268 0.00600 4.47 fps and Reynolds number, Nr, , is VD 4.47 X 0 0875 Nn 3.88 X 10-* 10,100 From Fig. 4, Chapter 4, using a roughness factor e 0.00015, whence e/D 0.00172, the friction factor / is found to be 0.0333. Substituting in Equation 10 yields L V* 4.47*2 X 32.16 e 35.8 ft of fluid -- 14A psia The friction loss could have been approximated two ways: (1) by using Fig. 2{ and (2) by using rig. 3 of this chapter in conjunction with Fig. 5 of Chapter 28. . In order to use Fig. 2, the viscosity of the oil must be known in SSU. As given above the kinematio viscosity of the oil at 113 F is 3.88 X 10~ sq ft per sec. From Table 6, 3.88 X 10"* sq ft per sec is equal to 37.9 SSU. Entering Fig. 2 at 37.9 SSU and reading friction loss for 12 gpm gives 12.8 ft per 100 ft. For a 300-ft coil this is 38.4 ft of fluid. This compares fairly well with the more exact figure of 35.8 ft as found by using the Fan ning equation. If the friction loss were approximated by Fig. 3 and Fig. 5 of Chapter 28, the result would have been 40.5 ft which is determined as follows: From Fig. 5 of Chapter 28, the loss for icater flowing at 12 gpm in a one-inch pipe is 1200 milinches per foot or 10 ft per 100 ft. In this case, then, the loss for water would be 30 ft. The correction factor for oil as compared to water is given in Fig. 3 as 1.35. The friction loss then would be 1-35 X 30 or 40.5 ft. Both of the approximation methods are conservative, but for large systems, this conservative approach may be costly. The pump must deliver 5380 gpm against a 14.8 psia bead. The heat exchanger must deliver 22.5 million Btun with an inlet temperature of 103 F and an outlet temperature of 123 F. Actually some allowance should be made for the temperature drop in the piping between the slab and the heat exchanger. Both the pump and heat exchanger manufacturers should be advised that the fluid is an oil ana will operate over a wide temperature and viscosity range. 0 a low-limit thermostat is placed in the fluid line so that the minimum fluid temperature is --10 F, it can be seen from Tables 5 and 6 that the viscosity can reach about 300 SSU. From Table 7, it -a-n be found that such a viscosity can reduce the pump head 5 percent and the capacity 3 percent. This means that the pump should be rated 14 a Mart at <T95 "" 15-6 psia and 097 " 5550 gpm' : The expansion tank should be designed in accordance with the procedure outlined in Chapter 28, Hot Water Heating Systems. The amount of expansion should be based on the change in volume from the low temperature limit to the high temperature limit. Assuming the temperature range to be -- 10 F to +123 F, the expansion would be an \ ^ * ~ 6.1 percent of the total volume in the system. REFERENCES 1 W. P. Chapman and S. Katunich: Heat requirements of snow melting systems (ASHAE Transactions, Vol. 62, 1956, p. 359). . 1 W. P. Chapman: Design of snow melting systems (Heating and Ventilating, April 1952, p. 95, and November 1952, p.'88). * W. P. Chapman: Calculating the heat requirements of a snow melting system (Air Conditioning, Heating and Ven- tUating, September 1956 through August 1957). . 4 W. P. Chapman: Snow melting system hydraulics (Air Conditioning, Healing and Ventilating, November 1955). * P. B. Gordon: Antifreeze protection for snow melting sys tems (Heating, Piping end Air Conditioning Contractors Na tional Association Official Bulletin, February 1950, p. 21). * C. S. Cragoe: Properties of Ethylene Glycol and Its Aqueous Solution (National Bureau of Standards, Society of Auto motive Engineers, CEC report No. 9). ' 7 W. P. Chapman: Arc thermal stresses a problem in snow melting systems? (Heating, Piping and Air Conditioning, June 1955, p. 104, and August 1955, p. 92). CHAPTER 50 PROCESS AND PRODUCT AIR CONDITIONING General Requirements for Manufacture, Processing, and Preservation,- Design Conditions and Application Data; Classification of Problems,- Moisture Content end Regain; Conditioning and Drying; Chemical and Biochemical Reactions; Crystallization; Control for Machining, Polishing, and for Static Electricity . Elimination; Laboratory Conditions; Calculations ROCESS and product air conditioning is concerned Air conditioning for industrial processes is so extensive Pwith the design and application of equipment for ob and involved that a detailed treatment is beyond the scope taining proper conditions for tbe manufacturing, processing, of this chapter. In many industries the exact conditions and preserving of material, equipment, and commodities. to be maintained are determined and known only by the This chapter includes a general discuffiion of these condi manufacturer who specifies them. In other industries there tions and also a comprehensive list of specific requirements is a wide variance between manufacturers' requirements, for various types of products. depending on results desired, experience, and cost considera GENERAL REQUIREMENTS FOR MANUFACTURE, PROCESSING, AND PRESERVATION tions. .. CLASSIFICATION OF PROBLEMS In order to apply air conditioning to industrial processes, the air-conditioning engineer must have a thorough under standing of the processing problems involved. Since indi vidual processes and machines are changing rapidly, air con ditions must be revised constantly to meet new requirements. Table 1 lists the temperatures and relative humidities required for storage of certain commodities, and for man ufacturing and processing of others. In some cases the temperatures and relative humidities listed in Table 1 have no direct influence upon the product itself, but do affect the efficiency of employees and, in turn, the work--"" manship, uniformity, and cost of production. Sometimes, a compromise between the known optimum condition for processing and that required for worker comfort is unavoid able. In general, any industrial air-conditioning problem in processing may be classified under one or more of the fol lowing: - 1. Control of regain. - 2. Control of rate of chemical reactions. 3- Control of rate of biochemical reactions. * 4. Control of rate of crystallization. 5. Control of temperature for close tolerance machining, and grinding. . 6. Control of dew point for protection of highly polished surfaces. 7. Control of humidity for static-electricity elimination. . 8. Control of conditions for material-testing laboratories. (Text continued on p. 687) Table 1 .... Temperatures and Humidities Applicable to Industrial Air Conditioning* Process Temp. F BAKERY Mixer (bread dough)................................ Fermenting.................................................. Proof box..................................................... Bread oven................................................... Cake oven.................................................... Bread cooler (room or tunnel) Vacuum 28.6 in...................................... 75-80 75-80 92-96 375-450 300-430 70-75 Cold room.................................... ............... Make-up room............................................ Cake mixing................................................ Cake mixing (sponge).............................. Crackersand biscuits............ '................. Wrapping...................................................... 40-45 75-80 70-75 95-110 60-65 60-65 Dried ingredients, storage..................... Fresh ingredients, storage...................... Flour storage............ ............................... Shortening (depending on tvne). star- age.............................................................. Sugar, storage............................................ Water, storage.......................................... Wax paper, storage.................................. 70 30-45 65-80 45-70 80 32-35 70-80 tut.% 40-50 70-75 80-85 80-85 65-70 65 50 60-65 55-65 80-85 50-65 55-65 35 40-50 Methods of Mixes Cooling 1. 35-40 F water circulated through mixer jacket. 2. 15-25 F brine. _ 3. Direct expansion, refrigerant circulated through mixer jacket. 4. Cracked ice added to dough in mixer. 5. Cold air introduced into mixer during mixing process. 6. Cooled agitators are used in mixers. Mixer Load Calculations Refrigeration is required to remove: excess ingredient, if any; heat generated by tbe beating and mixing of dough; ex cess heat in mixer body; heat of hydration of flour and water; and heat absorbed by mixer from atmosphere during mixing. Additional factors are the design and speed of mixer, con sistency, kind and mass of dough. Data Used in Calculations: 1 bbl. flour = 200 lb. Heat of hydration " 6.5 Btu per lb of flour. Specific heat of flour 0.42 Btu per lb. Water is 65% of weight of flour. Flour is 65% of batch. ' Sponge is 60% of batch. Total motor output is converted to heat in the mixer. In fermenting rooms recent practice is to use direct radiation for heating, atomizing sprays lor humidifying, and gravity con- lafarstklMD in Table I ia drawn from many sources. See bibliography at sod of chapter. 682 CHAPTER 50 1959 Guide Table 1 .... Temperatures and Humidities Applicable to Industrial Air Conditioning--(Continued) BAKERY (Continued) vection cooling surfaces for temperature reduction and dehumidifying--thereby eliminating objectionable air currents. Proof box and bread cooler conditions vary slightly for dark bread. Cakes are sterilised by ultra-violet rays before wrapping. ProcM* rmp. F JLH.% BANANAS Enrobing Procut rmp. F CANDY (CHOCOLATE) 50 to 55 40 to 50 60 54 to 56 85 to 90 Forced ripening is accomplished in 4 to 5 days while slow ripening is extended to 7 to 9 days with lower temperatures. The green fruit with a pulp temperature of 66 F is placed in a ripening room at 68 F and 90 to 96 percent relative humidity until itoegins to change color. The temperature is then lowered sharply to 60 F (or slightly less) dependent upon how quickly the fruit is to be moved. Typical refrigeration load for ripening room per carlot, with an 85 F ambient temperature: ' Insulation and electric load -- 0.4 ton. Live load = 0.9 ton. Pull down load (from 68 F to 60 F) -- 1.6 ton. Minimum carlot--20,000 lb which represents about 300 stems. Since bananas give off minute quantities of ethylene and pos sibly other gases necessary for ripening, ventilation during the early stages of ripening is undesirable. Cooling unit to be used to provide a complete air change every 1)4 to 2 min. Provide a heating system with a rated capacity to warm the fruit at a rate of not less than 2 deg per hr. Specific heat--0.9 Btu per (lb) (F deg). Approximate rate of evolution of heat by bananas when stored at temperatures indicated: Bananas at 54 F * 3,300 Btu (per ton) (24 hr). green at 68 F -- 8,360 Btu (per ton) (24 hr), turning at 68 F = 9,240 Btu (per ton) (24 hr), ripening at 68 F -- 8,360 Btu (per ton) (24 hr). ` Room BREWING Temp. F tLH.% * If wooden tankage is used, other wise humidity controlled to prevent condensation on walls and ceiling. 32 to 35 60 max. 75 7K 75 75 * 75 Wort cooled to 47 F for lager, 64 to 69 F for ale, by evapora tive cooling or use of double pipe or plate type coolers with counterflow of cooling medium. Fermentation produces 250 Btu per lb of sugar fermented. Lager fermented five days at 55 to 60 F, ale at 68 to 75 F, then corned to storage temperature. . Bottled beer pasteurised by heating to 140 F in twenty min utes, maintaining temperature for eighteen minutes, then cooling to 80 F in twenty minutes. Canned beer requires one - third less time. Cold water, brine, direct-expansion ammonia, or propyleneglycol and water solutions may be used as the cooling medium. 65 to 70 Tempering room. = Ventilation only 40 to 50 Tunnel discharge room requires a dew point lower than the temperature of the product leaving the tunnel. During the summer months the product is usually held in the tempering room for 24 hours prior to shipping. Recovery of sugar fly in coating kettle rooms is accomplished by use of cyclone-type dust collecting devices. Supply air to coating kettles is maintained at 85 F dry-bulb ana 61 F wetbulb temperature. Bacteriological control is employed. Load calculations for hand dipping rooms are based on 100 lb of 90 F chocolate per (worker) (hr). Specific beat of chocolate -- 0.30 to 0.56 Btu per (lb) (F deg). Latent heat of fusion -- 34 to 40 Btu per (lb) (F deg). Freezing point = - Sweet milk chocolate -- 86 F. Dark chocolate =* 90 to 92 F. . Pw*a Imp. F CANDY (HARD) 40 to 45 Tempering -- (Ventilation only) 65 to 75 45 to 50 Hot rooms used in the drying of jellies and gums are main tained at 120 to 150 F. A purge system using 100 percent out side air, bypassing the heating coil, is incorporated to produce rapid cooling of both the product and the room. Cold rooms for cooling marshmallows and cast creams are maintained at 75 to 80 F with a relative humidity of 45 to 50 percent. Uniform air distribution is essentiaL Standard starch drying equipment is employed. Filtration of air is required. Proem Temp. F CERAMICS 80 60 to 70 75 to 80 48 Relative humidity has no effect on the manufacture of the products. . Temperature and humidity must be controlled in the dec orating shop in the whitew&re plants, and the decalcomania production room. . Dust control is essential and the dust count must be held down to four million particles per cubic foot due to the danger of silicosis.______________________________________________________ Process and Product Air Conditioning 683 Table 1 .... Temperatures and Humidities Applicable to Industrial Air Conditioning--.(Continued) Proa* Temp. F Ui.% Pracen Temp. F CEREAL Packaging.................. '................................ 75-80 CITRUS FRUIT 45-50 * Prior to transcontinental ship ment 84 to 88 86 to 88 Careful consideration must be given to air volumes, air temperatures, humidity, ventilation, and distribution. In regions where end rot is prevalent, it may be necessary to store grapefruit at temperatures of 32 to 34 F for a period not exceeding six weeks. Lemon and grapefruit storage requires an air-conditioning system to (1) maintain a constant temperature, (2) maintain a high relative humidity, (3) ventilate to 0.1% COi content. (4) obtain uniform air distribution, and (5) provide air washing or air filtration. Load calculations include (1) transmission losses, (2) inter nal load-fruit cooling and respiration, cooling fruit boxes, electric load, and people, and (3) outside air load--72 cfm per carlot. - Specific heat--Btu per (lb) (F deg): Lemons 0.94, Grapefruit 0.87, Boxes 0.40 Heat or Evolution in Btu Peb (ton) (24 hb) Temp. IXDOIU ` Crapefrwf 32 580 460 40 810 ' 1070 60 2070 2770 80 6200 4180 ELECTRICAL PRODUCTS Electronics and X-Ray: Coil and transformer winding.......... Electrical Instruments: 72 Thermostat assembly and calibra- Humidistat assembly and calibra- Smatl Mechanisms: Switchgear: 15 40 50 to 55 50 to 55 40 to 45 50 Thermal circuit breakers assembly Water wheel generators: Rectifiers: Processing selenium and copper ox- Dust control is essential in these processes - 74 30 to 60 30 to 40 FLOOR COVERING Linoleum: Mechanical oxidizing of linseed oil.. 90 to 100 * grains per pound abs. hum. 160 to 250 20 to 28 30 to 50 60 gr* Approximately 10 percent of the cooling load is considered as latent heat load. -- In a conventional system the air required is ooe cfm per storage box or 650 cfm per carload, resulting in a m*ll tem perature rise in the supply sir making possible the required high humidities. In a combination system the air required is one cfm per sq ft of floor area or 300 cfm per carlot with the addition of auxil iary humidifying nozzles.to maintain the required high hu midities. . Installation of metal ducts is required. Ductwork made of insulation board is sometimes preferred. Proceti Teap. F tui.% DISTILLING Some operations are stabilized to prevent mold growth. Precise control of.temperature and humidity is required for mechanical oxidizing of linseed oil. The rate of flow and the temperature of cooling water in the jacket surrounding the tank must be controlled. Air filtration is recommended for the storing process. FOUNDRIES Core making................................................ Mold making: Bench work............................................. Floor work.............................................. Pouring......................................................... Shakeout.................................. .... Cleaning Room.......................................... * Winter design temp. 60 to 70 60 to 70 - 40 40 to 50 55 to 65 Storage: 60 32 to 34 65 to 72 35 to 40 45 to 60 50 to 60 Mashing done at 150 to 155 F, then cooled to 64 to 68 F. - Yeast culture fermented at 170 F, then cooled to 70 to 72 F. Yeast propagated at 150 to 154 F. Mash heated to 165 F and then cooled to 80 F, then pitched . with yeast and fermented at mTimnm temperature of 85 F. Cooling for various distilling processes normally accom plished by use of river or well water depending on tempera tures and availability. Low humidity end dust control important where grains are ground. Viscous filters preferred as mold spores and bacteria are trapped in the viscous film, preventing propagation. The charging room is usually unheated. In core making fume-exhaust hoods are required for oven and for cooling areas adjacent to ovens. ' In mold making provide hoods at transfer points with wet collector dust removal system. Use 600 to 800 cfm per hood. Pouring rooms require two-speed powered roof ventilators. Design for minimum of two cfm per sq ft floor area at low speed. Shielding is required to control radiation from hot surfaces. Proper introduction of air will minimize preheat requirements. In shakeout room provide hoods with wet-collector dustremoval system. Exhaust 400 to 50Q cfm per sq ft grate area. Roof ventilators are generally not effective. In cleaning room provide hoods for grinders and cleaning equipment with dry cyclones or bag-type collectors. ' - Winter ventilation (preheated) is required to the extent of replacing exhausted air. Summer ventilation is usually sup plemented by use of pedestal fans. Spot coolers are sometimes used in larger installations. 684 CHAPTER 50 1959 Guide ' Table 1 .... Temperatures and Humidities Applicable to Industrial Air Conditioning--(Continued} Frocen j Temp. F 1Ul.% LIBRARIES AND MUSEUMS {Concluded) FUR Check Figures fob Coolino Estimates n :^ 110 18 to 20 40 to 50 5 to 65 Shock treatment, for eradication of any insect infestations, requires the lowering of the temperature to 18-20 F for 3 to 4 days, then raising it to 60-70 F for 2 days, then lowering it once again to 18-20 F for 2 days and raising it to the storage tem perature. Furs remain pliable, oxidation is reduced, and color and luster are preserved when stored at 40 to 50 F. ' Mold growth is prevalent with humidities above 80 percent, while hair splitting is common where humidity is lower than 55 percent. '1 ProceH ILH.% low Medium Square feet Boor area per person.... Watts per sq ft of floor area........... Room sensible heat, Btu per (hr) Grand total heat, Btu per (hr) (sq ft).......................................................... Sensible heat factor............................ Cooling load per person, tons.......... cfm per sq ft of floor area................ 40 20 30 0.73 0.12 0.92 60 1 35 51 0.83 0.23 1.60 MALTING (BREWING) Steeped 24 to 72 hr in 45 to 65 F water. Germinated six days at 55 to 75 F. Kilned at temperatures of 120 to 175 F. High 80 45 75 0.90 0.40 Manufacturing. Rolling.............. Stripping.......... Breaking.......... Wrapping......... GUM MALTING (DISTILLING) Germinated twenty days at 63 F. 77 33 Germination produces total heat of 16,000 Btu/bushel at 68 63 varying rate depending upon grain and process. 72 53 74 47 74 58 Temp. F ILH.% LEATHER Diving: Vegetable tanned.................................. Storage.................................................... . - - 70 120 50-60 75 45 40-60 After leather is moistened in preparation for rolling and stretching, it is placed in an atmosphere held at room tempera ture with a relative humidity of 05 percent. Leather is usually stored in warehouses without tempera ture and humidity control. However, it is necessary to seep humidity below 85 percent to avoid mildew. Air filtration is recommended for toggle machines. Procstx Temp. F IM.% MATCHES Manufacture. Drying.......... Storage.......... 72 to 74 70 to 75 60 to 62 50 40 50 Water evaporated is 18 to 20 lb per million matches simul taneously with the setting of the glue. The match machine will turn out about 750,000 matches per hour. MUSHROOMS Sweating-out period. Spawn added............. Growing period........ Storage....................... 120 to 140 60 to 75 nearly sat. 48 to 60 moderate 32 to 35 80 to 85 LENSES (OPTICAL) Grinding........................................... .......... 75 80 45 80 The air must be free of dust and temperature held constant. To acquire desired cleanliness of air a combination of im pingement and electrostatic filters are used. Dust collectors are required for grinding operations. Room* Ternp. F LIBRARIES AND MUSEUMS ILH.% As spawn starts to grow, it is necessary to abruptly cool the mushroom house by 15 deg in a 12 hr period (approx.) . Usually, thU is the controlling factor io selection of refrigeration equip ment, unless there is portable equipment available for such a purpose. Ductwork is usually of wood, due to the deterioration of ferrous metals during sweating-out period. Air filtration is essential in spawn rooms. Viscous filters are preferred, as mold spores are trapped in the viscous film. Odorless oil should be used. Heat ol emission is 4.Btu per (hr) (sq ft of growing surface). Frocou romp. F ILH.% Book storage 70-80 40-50 40-50 Spray type dehumidifiers used to eliminate SO*. Water treatment is essential to. maintain between 8.5 and 8.0 pH. Reheat is usually needed for refrigeration cycle due to the low sensible heat load. In extremely cold weather a lower relative humidity is re quired to prevent condensation on walls. Positive high and low limit relative humidity controls are used. Do notloeate water or steam piping where leakage can cause damage._______________________________________ .____________ PAINT APPLICATION Lacquers: Air drying................................................ Baking....................................................... Oil Paints: Air drying........................:...................... Paint Spraying........................................... 70-00 180-300 60-00 75 60 Spray booths to have 100 fpm face velocity. Make-up air must be preheated. Ovens must have air removed to keep fumes below explosive concentration. Equipment must be explosion- proof throughout.___________________________________ .________ _ Process and Product Air Conditioning 685 Table 1 .... Temperatures and Humidifies Applicable to Industrial Air Conditioning--{Continued) Room or Procast remp.F ILH.% fr"" T.mp.F ji.% PHARMACEUTICAL Powder storage (prior to mfg.)............ Manufactured powder storage and packing areas.......................................... Milling room................................. ............. Tablet compressing.................................. Tablet coating room................................. Effervescent tablets and powders....... Hypodermic tablets.................................. CoAoids......................................................... Cough syrups.............................................. Glandular products.................................. Ampule manufacturing............................ Gelatin capsules........................................ Capsule storage.......................................... Micro-analysis............................................ Biological manufacturing....................... liver extracts............................................. Serums........................................................... Animal rooms............................................. Small animal rooms.................................. 70 to 80 75 to 80 80 70 to 80 80 90 75 to 80 70 80 78 to 80 80 78 75 80 -80 70 to 80 74 to 78 75 to 80 75 to 78 30 to 35 15 to 35 35 40 35 15 30 30 to 50 40 5 to 10 35 40 to 50 35 to 40 50 35 20 to 30 50 40 47 to 48 Gelatin capsules require varying relative humidities, de pending upon size of capsule. Moisture content should not exceed 0.25 g per cu ft. Various kinds of gelatin require different temperatures. . Penicillin incubation process requires holding temperature within H deg F, with temperatures and humidity rigidly con trolled during all manufacturing phases. - Ampule filling requires a 20 percent relative humidity when especially fine powders are used. Uncoated tablet manufacturing requires accurate control of temperature and relative humidity, since low relative humidity causes formation of a hard outer layer, and bigh'relative hu midity retards drying at the proper rate. liver extracts require & low relative humidity after they are . dried. Temperatures higher than 80 F will cause the extracts to deteriorate. Tablet coating requires the control of the temperatures-of all ingredients and the temperature of air introduced to coat ing pans. Sterile conditions are essential in many pharmaceutical processes. Provide euitabie air exhaust to remove surplus ma terial from tablet compressing machine. Air filtration is generally required, with positive air filtra tion in some areas._______ Animal Rooms in Pharmaceutical Laboratories In the following tabulation each of the items mentioned is equivalent in metabolism to one,man: PHOTO STUDIO 30-40 70 60 45 Heat liberated during printing, enlarging, and drying proc esses is removed through an independent exhaust system, which also serves the lamp houses and dryer hoods. Dust control is essential, and absolute filtration is required in some areas. Froew* Temp. F ILH.% PHOTO MATERIAL Coated Paper and Film Storage.......... 20-125 65-75 70-75 70-75 60-80 40-50 40-80 40-60 40-65 40-65 45-50 40-50 Spray water must have algae inhibitor. Positive dust control must be maintained and absolute filtration is essential. In nitrate film area take proper precautions against fires. Recirculated air used for film drying is passed through acti vated carbon filters. Relative humidity for film storage should never exceed 60 percent with.a minimum of 25 percent. . Frocea Temp. F *-*.% PLASTICS Manufacturing areas: Thermo setting molding com- 75 to 80 25 to 30 45 to 65 Absolute filtration is required in some areas. Collection and removal of dust and fumes is essential. Quantity Amaaf Weigh* Each 672 White Mice 21 g 110 Rats 200 g 73 Rats 400 g 70 Guinea Piss 410 g 21 Rabbits 2.6 kg 16 Cats 3.0kg 16 Monkeys 3.0 kg 5 Dogs 14.0 kg Dogs are generally the worst offenders as far as odor genera tion is concerned. Decontamination of exhaust air is recommended in popu lated areas. For good air quality conditions the following space per ani- nial and total air circulation (all outdoor or decontaminated m recirculation) should be provided: .' Animal cu ft cfm Animal cfm Mice ` Rats Guinea Pies Rabbits 3 4 6 10 0.5 0.75 1.0 1.9 Dogs 1.5 10.0 28.0 PLYWOOD Temp. F ILH.% POULTRY RAISING Brooder: Battery room: 70-75 15 to 25 30-60 45-60 70-80 Maximum ventilation is required for laying quarters during the summer months, while an attempt is made to maintain a temperature 10 deg above or below outdoor temperature during the winter, to minimize condensation on the exterior , walls. This applies to houses not having forced ventilation systems. 686 CHAPTER 50 1959 Guide Table 1____ Temperatures and Humidities Applicable to Industrial Air Conditioning--(Continued) (LH.% Process j Temp- F KJ1.% PRECISION MACHINING 75-80 45-50 room.......................................................... Gasket storage........................................... Cement and glue storage........................ Precision parts machining..................... 75-80 100 65 75 35-40 50 40 45-50 Accurate gaging and inspection -........ Precision gage manufacture and ad justment .................................................. Precision gear drive assembly.............. Watch main spring calibration............ Gage room.................................................. Precision parts--honing.-...................... 75 68-75 72 76 78 75-80 45-60 45-50 42-50 45 50 35-45 For product improvement and increased personnel efficiency some manufacturing areas are being provided with summer air conditioning, where air conditioning is not provided, an ample supply of outdoor air and air motion are relied upon to provide acceptable working conditions. Low relative humidity is usually maintained to prevent cor rosion. Temperature control within a narrow range is more important than temperature maintained. Dust control is required wherever polishing operations occur. Air distribu tion is important to maintain constant conditions through out the area. Prewi . Tp. F tH.% PRINTING Pressroom: Newspaper and other web printing.. Stock room: Binding, cutting, drying, folding, and 5 to 8% above pressroom *k same as pressroom 75-80 75-80 75-80 73-80 70-80 70-80 73-80 46-48 45-50 50-55 b 45-50 50 Lithography requires constant humidity control of entire pressroom with paper conditioned 5 to 8 percent higher rela tive humidity at start. All printing requires conditioned paper otherwise it will not lie flat, with 40 to 45 percent R.H. low limit to eliminate static electricity; and 60 percent R.H. high limit to prevent swelling of the rolls and slow ink drying. Tem perature is not criticalTbut extremes should be avoideo due to softening of the rolls at high temperature and improper ink distribution at low temperatures. Hoods must be provided for gas dryers, with solvent recov ery recommended for all except job shops. Exhaust system with dust collectors incorporated is required for type and plate cleaning areas. Check use of gasoline and other solvents. Nor mal air cleaning is adequate. Air distribution must prevent drafts on paperTo storage or process. Gas flame dryers impose unusual loads. Air frompress and storage rooms should not be recirculated through office areas. Tamp. F REFRIGERATION EQUIPMENT 75 70 to 76 75 65 to 82 (LH.% 40 30 to 45 30 to 50 47 RUBBER DIPPED GOODS Dipping surgical articles....................... Storage prior to manufacture............... Laboratory (AJ3TM Standard)............. 90 80 75-90 60-75 73.4 25-30 25-80 40-50 50 Solvents used in manufacturing processes are usually ex plosive and toxic, requiring positive ventilation. Volume manufacturers usually install a solvent recovery system.________________ ' ' TEA Packaging. 65 65 Ideal moisture content is 5 to 6% for quality and weight. Low limit moisture content for quality is 4%. TEXTILES Cotton: Opening....................................... Picking..................................................... Carding, Winter.................................... Carding, Summer......................... or Carding, Summer........................ or Carding, Summer........ Drawing............................ Roving.............................. Ring Spinning Conventional............ Long Draft.................. Frame Spinning............. Spooling and Warping. Weaving............................ Cloth Room.... .......... Combing........................... Linen: Carding.................. Spinning........................... Weaving............................ Woolens: Pickers............... Carding................ '.......... Spinning........................... Dressing........................... Weaving light goods................ Overcoating (32 oz.). Drawing............................ Worsteds: Carding........... Combing......................... Pilling................................. Top Storage................... Drawing.......................... Cap Spinning................ Spooling ana Winding Weaving.............. Finishing............ Silk: Preparatory. Weaving.............. Dressing.............. Spinning............. Throwing............ Rayon: Spinning.. Throwing............ Weaving Regenerated. Acetate......... Spun rayon.. 70-75 75 75-80 83 85 87 80 80 80-85 80-85 80-85 78-80 78-80 75 75 75-80 75-80 80 80-85 80-85 80-85 75-80 . 80-85 80-85 75 80-85 80-85 80-85 70-85 80-85 80-85 75 80-90 80 80 80 80 55-60 55-60 55 90 80 70 60 GO 70 55 55-60 65 '70-85 65-70 50-65 60 60 65-70 50-60 60-65 50-60 65 * 65-70 65-70 75-80 65 50-55 65-70 55-70 60-65 60-70 60-65 65-70 60 50-60 55-60 50-65 "55-60 80 Process and Product Air Conditioning 687 Table 1-------Temperatures ond Humidities Applicable to Industrial Air Conditioning--(Concluded) Pracii Temp. F LH.% TEXTILES (Continued) Rayon (Continued): Picking..................................................... Carding, roving, drawing................... Knitting Viscose or cuprammonium............. Acetate................................................. Laboratory (ASTM)............................ 75-80 80-90 80-85 80-85 70 50-60 50-60 65 60 65 Rayon synthetic fiber processing: Viscose Preparatory........................................ Weaving........................................... ... Celanese Preparatory.................................;... Weaving............................................... Nylon . Preparatory........................................ Weaving................................................ 80 80 80 80 80 80 60 60 70 70-75 50-60 50-60 Cotton: Relative humidity maintained in ring spinning de pends on staple, twist, and whether. leather aprons are used for conveying long draft stock. Aprons readily absorb moisture causing cotton to stick when relative humidity is above 55 per cent. With conventional 3 or 4 roll spinning, relative humidity may be as high as 70 percent dependent upon draft, twist, ana staple. Relative humidity carried in cotton weaving depends upon construction of the cloth. When automatic machines are to be tended and the warps are heavily sized, it may be as high as 90 percent. Woolen; In woolen spinning, the relative humidity main tained for mules is generally 55 percent, with conditions over frame spinning at 55 to 60 percent. Both types of spinning de pend on the class of stock spun, also the regain in the roving. Worsted!; Top storage temperature depends on whether cellar long period conditioning at low temperature or quick conditioning at high temperature is used. Weaving relative humidity depends upon staple, quality, and construction. Filtration of air is essential. Rayon manufacture: The steeping room, where sheets of raw material are dipped in caustic soda then broken into a fine matted crumb, is held at 70 F and 55 percent relative humidity. Relative humidity is held down to prevent condensation on cold pipes and jackets. In churn room, where sodium cellulose is converted into cel lulose xanthate, temperatures of 75 to 80 F are TnintAnvf while humidity control is not important. Room temperatures are held below 85 F during the summer months. The crumb is dumped into aging tanks located in a room held at 73 F with no humidity control. For spinning operations it is desirable to limit the tempera ture to 90 F with a minimum relative humidity of 70 percent for the summer, while 70 percent and 75 F are desirable for the winter months. In the storage room, where the material is held for later rocessing, design conditions are 85 F and 100 percent relative umidity. The material is washed, desulfurized, bleached, and then washed again. It is then placed in a drier where controlled con ditions of 100 deg and o5 percent relative humidity are re quired to bring the rayon back to the proper regain. In the coning room, where winding machines place the rayon yarn on cones, temperature is held at a mwirnmn of 80 F. Rela tive humidity is held at 55 percent. Process TOBACCO r*ap. F Stemming and stripping. >.................... Filler tobacco casing and condition* Filler tobacco storage and preparaWrapper tobacco storage and condi- 75 to 85 75 ILH.% 55 to 65 70 to 75 75 In preparation for stripping, the tobacco undergoes a soften ing operation, whereby it is automatically heated, moistened, and then cooled. Control of moisture regain, and of chemical and biological reactions is required in tobacco processing. Exact temperature and humidity conditions maintained are usually trade secrets as they affect the finished product. (Text continued from p. 681.) Moisture Content and Regain In the manufacture or processing of hygroscopic materials such as textiles, paper, wood, leather, tobacco, and food stuffs, the temperature and relative humidity of the air have a marked influence upon the rate of production and upon the weight, strength, appearance, and general quality of the product. The moisture content of materials having a vegetable or animal origin, anH to a lesser extent minerals in certain forms, comes to equilibrium with the moisture of the surrounding air. This moisture content is known as regain. Standards of regain are fixed in the trade, and are the fundamental basis for the control of certain physical qualities of the material during manufacture. Manufacturing economy requires that the moisture con tent be maintained at a level favorable to rapid and satis factory manipulation, and to a minimum loss of material through breakage. A uniform condition is desirable in order that high-speed machinery may be adjusted perma nently for the desired production with a minimum loss from delays, wastage of raw material, and defective product. Moisture content refers to free moisture (as in a sponge) and to hygroscopic moisture (which varies with atmospheric conditions). It is usually expressed as a percentage of the , total weight of material. Regain is more specific and refers only to hygroscopic moisture. It is expressed as a per centage of the bone-dry weight of material. For example, if a sample of cloth weighing 100.0 g is dried to a bone-dry weight of 93.0 g, the loss in weight, or 7.0 g, represents the weight of moisture originally contained. This expressed as a percentage of the total weight (100.0 g) gives the moisture content of 7 percent. The regain, which is.expressed as a percentage of the bone-dry weight, is (7jO/93.Q) X 100 = 7.5 percent. The use of the term regain does not imply that the material as a whole has been completely dried out and has re-absorbed moisture. ' A basis for calculating the regain of textiles is obtained by drying, under standard conditions, a sample from the lot, and the dry weight thus obtained is used in the calcula tions to determine the regain. Table 2 shows the regain or hygroscopic moisture content of several organic and inorganic materials when in equi librium at a dry-bulb temperature of 75 F and various 688 CHAPTER 50 1959 Guide Ckmaflcofton Table 2 .. - - Regain of Hygroscopic Materials Content Expressed to teiwrf of Dry Weight of the Subctonee at Various Refafrre Humidities--raporohm>, 75 F Moteriof Description Refafiva Humidity--Percent 10 20 30 40 50 60 70 80 90 Authority Textile Fibers Cotton Cotton Cotton Silk Linen Jute Hemp Sea island--roving American--cloth 2.5 2.6 Absorbent Australian me- rino--skein Raw cbevennes --skein Table cloth Dry spun--yarn Average of sev- era! grades Manila and sisal--rope 4.8 4.7 3:2 1.9 3.6 3.1 2.7 3.7 4.6 5.5 6.6 7.9 9.5 11.6 14.1 Hartshorne 3.7 4.4 5.2 5.9 6.8 8.1 10.0 14.3 Schloesing 9.0 12.5 15.7 18.5 20.8 22.8 24.3 25.8 Fuwa 7.0 8.9 10.8 12.8 14.9 17.2 19.9 23.4 Hart- shorne 5.6 6.9 8.0 8.9 10.2 11.9 14.3 18.3 Schloes- ing 2.9 3-6 4.3 5.1 6.1 7.0 8.4 10.2 Atkinson 5.4 6.5 7.3 8.1 8.9 9.8 11.2 13.8 Sommer 5.2 6.9 8.5 10.2 12.2 14.4 17.1 20.2 Storch 4.7 6.0 7.2 8.5 9.9 11.6 13.6 15.7 Fuwa Rayons Viscose Nitrocellulose Cuprammonium Cellulose Acetate Average skein 4.0 5.7 6.8 7.9 9.2 10.8 12.4 14.2 16.0 Robertson 0.8 1.1 1.4 1.9 2.4 3.0 3.6 4.3 5.3 Robertson Paper M. F. News- Wood pulp--24% 2.1 3.2 4.0 4.7 5.3 6.1 7.2 8.7 10.6 NBS print ash H.M.F. Writ- Wood pulp--3% 3.0 4.2 5.2 6.2 7.2 8.3 9.9 11.9 14.2. NBS ing ash White Bond Rag--1% ash 2.4 3.7 4.7 5.5 6.5 7.5 8.8 10.8 13.2 NBS Com. Ledger 75% rag--1% ash 3.2 4.2 5.0 5.6 6.2 6.9 8-1 10.3 13.9 NBS Kraft Wrap- Coniferous 3.2 4.6 5.7 6.6 7.6 8.9 10.5 12.6 14.9 NBS ping Misc. Organic Materials Leather Catgut Glue Rubber Soap Tobacco Sole oak-- tanned Racquet strings Hide Solid tires ' Timber (average) White Cigarette 5.0 8.5 11.2 13.6 16.0 18.3 20.6 24.0 29.2 Phelps 4.6 3.4 0.11 3.0 1.9 5.4 7.2 4.8 0.21 4.4 3.8 8.6 8.6 5.8 0.32 5.9 5.7 11.0 10.2 6.6 0.44 7.6 7.6 13.3 12.0 7.6 0.54 9.3 10.0 16.0 14.3 9.0 0.66 11.3 17.3 10.7 0.76 14.0 12.9 19.5 16.1 25.0 19.8 11.8 0.88 17.5 19.8 33.5 21.7 12.5 0.99 22.0 23.8 50.0 Fuwa Fuwa Fuwa Forest P. Lab. Fuwa Ford Foodstuffs White Bread Crackers Macaroni Flour Starch Gelatin 0.5 1.7 3.1 4.5 6.2 8.5 11.1 14.5 19.0 Atkinson 2.1 2.8 3.3 3.9 5.0 6.5 8.3 10.9 14.9 Atkinson 5.1 7.4 8.8 10.2 11.7 13.7 16.2 19.0 22.1 Atkinson 2.6 4.1 5.3 6.5 8.0 9.9 12.4 15.4 19.1 Bailey 2.2 3.8 5.2 6.4 7.4 8.3 9.2 10.6 12.7 Atkinson 0.7 1.6 2.8 3.8 4.9 6.1 7.6 9.3 11.4 Atkinson Misc. Inorganic Materials Asbestos Fiber Silica Gel Domestic Coke Activated Charcoal Sulfuric Arid Finely divided Steam activated H,SOt 0.16 5.7 0.20 7.1 33.0 0.24 9.8 0.40 14.3 41.0 0.26 12.7 0.61 22.8 47.5 0.32 15.2 0.81 26.2 52.5 0.41 17.2 1.03 28.3 57.0 0.51 18.8 1.24 29.2 61.5 0.62 20.2 1.46 30.0 67.0 0.73 21.5 1.67 31.1 73.5 0.84 22.6 1.89 32.7 82.5 Fuwa Fuwa Selvig Fuwa Mason Process and Product Air Conditioning 689 relative humidities. The effect of temperature as compared to the relative humidity is comparatively unimportant, al though sudden changes in temperature cause a slight change in regain even when the relative humidity remains sta tionary. Changes in temperature do, however, affect the rate of absorption or drying, although this property gener ally varies with the nature of the material, its thickness and density. When hygroscopic materials absorb moisture from the surrounding air, they deliver to the air sensible beat equiv alent to the latent heat released by the moisture to the material. This amount of heat should be included in the load estimate. Conditioning and Drying In general, the materials may be exposed to desirable humidities for treatment coincidentally with the manufac ture or processing of the materials, or they may be treated separately in special enclosures. This latter treatment may be classified as conditioning or drying. The usual purpose of conditioning or drying is to establish a desired condition of moisture content and to regulate the physical properties of the material. When the final moisture content is lower than the initial one, the term drying is applied (See Chap ter 53). If the final moisture content is to be higher, the process is termed conditioning. In the case of some textile products and tobacco, for example, drying and condition ing may be combined in one process for the dual purpose of removing undesirable moisture, and accurately regulating the final moisture content. Frequently, conditioning or drying is made a continuous process in which the material is conveyed through an elongated compartment by suitable means, and subjected to various controlled atmospheric conditions. Control of Rate of Chemical Reactions A typical example of control of the rate of chemical re actions occurs in the manufacture of rayon. The pulp sheets are conditioned, cut to size, and passed through a mercerizing process. It is essential that, during this process, close control of both temperature and relative humidity should be maintained. The temperature controls the rate of reaction directly, while the relative humidity maintains a constant rate of evaporation from the surface of the solution, and main tains a solution of known strength during the mercerizing period. Another well-known example in this class is the drying of varnish which is an oxidizing process dependent upon temperature. High relative humidities have a retarding effect on the rate of oxidization at the surface, and allow the internal gase3 to escape freely as the chemical oxidizers cure the varnish from within. This produces a surface free from bubbles and a homogeneous film throughout. Desirable temperatures for drying varnish vary with the type. A relative humidity of 65 percent is beneficial. Control of Rate of Biochemical Reactions In the field of biochemical control, industrial air condi tioning has been applied to many different and well-known products. All problems involving fermentation are classed under this heading. As biochemistry is a subdivision of chemistry, subject to the same laws, the rate of reaction may be controlled by temperature. An example of this is the dough room of the modem bakery. Yeast develops best at a temperature of 80 F. A relative humidity of 70 percent is maintained to hold the surface of the dough open to allow the carbon dioxide gasses formed by the fermentation to pass through and produce a loaf of bread, when baked, of even, fine texture without large voids. Control of Rate of Crystallization The rate of cooling of a saturated solution determines the rise of the crystals formed. Both dry- and wet-bulb temperatures are of importance, as the one controls the rate of cooling, while the other, through evaporation, changes the density of the solution. In the coating pans for pills, gum, and nuts, a heavy sugar solution is added to the tumbling mass. As the water evaporates, each separate piece is covered with crystals of sugar. A smooth, opaque coating is only accomplished by blowing into the kettle the proper amount of air at the right dry- and wet-bulb temperatures. If the cooling and drying are too slow, the coating will be rough and semitranslucent, and the appearance unsightly; if too fast, the coating will chip through to the interior. Only by balancing temperature, relative humidity, and volume of air to the sugar solution, can the proper rate be obtained and a perfect coating assured. Control of Temperature for Close Machining Tolerances Where tolerances must be held within 2 or 3 ten-thou sandths of an' inch, as in the manufacture of precision instruments, tools, and high quality lenses, temperature variations may cause expansion and contraction of material to an extent that will seriously affect the quality of the work. This type of work usually requires close temperature control to assure accuracy and uniformity of the product. Usually the temperature level with respect to the product is not as important as controlling the temperature within close limits. For this reason, conditions are usually selected within the comfort range. Control of Dew Point for Protection of Polished Surfaces In the manufacture of certain metal articles, the presence of fingerprints, tarnish, or etching cannot be tolerated in the finished article. If these articles are manufactured under conditions of effective temperatures that will cause the hands to perspire, an unsatisfactory product will result. The salt and acid contained in body perspiration, when deposited on the highly polished article, can show corrosion and rust within a few hours if examined under a microscope. It is'therefore important to maintain temperatures and relative humidities (dew point) low enough to prevent sweating of the hands. In addition, the manufacture of polished surfaces usually requires a better-than-average job of air filtering to avoid abrasion of the surfaces. Control of Humidity for Reduction of Static Elec tricity The presence of static electricity is often detrimental to the satisfactory and economical processing of many light materials, such as textile fibers and paper. It is also ex tremely dangerous where explosive atmospheres or materials are present. Fortunately, this hazard is minimized by in- 690 CHAPTER 50 1959 Guide creasing the relative humidity to at least 55 percent, if the material processed is not damaged thereby. It must be borne in mind that for successful elimination, the air that actually comes in contact with the material in the machine must be at a relative humidity of 55 percent or more. As some machines consume a great deal of power, which is converted- directly into heat, the temperature in the marhinft may be considerably higher than the tempera ture adjacent to the machine where the relative humidity is normally measured. In such cases, the relative humidity in the mm-hina will be appreciably lower than that elsewhere in the room, and it may therefore be necessary to maintain a room relative humidity of 65 percent, or even more, to maintain the desired humidity. Control of Conditions for Material Test Labora tories Laboratories having controlled conditions of temperature and humidity, are common, not only for the purposes of scientific research, but also for routine testing and for quality production control. A control of temperature and humidity within fairiy-close plus or minus limits is usually required. Laboratories designed-for scientific research may require control of conditions over a wide range, whereas the routine testing laboratory or quality control laboratory will usually be designed to maintain the ASTM Standard Conditions of 50 percent relative humidity and 23 C (73.4 F) temperature. CALCULATIONS The methods for determining the heating and cooling loads for the various industrial processes are similar to those outlined in Chapters 12 and 13. Some factors affecting heating or cooling requirements are given in Table 1. Be cause of the large number of motors and heat producing units usually found in an industrial application, it is par ticularly important that operating allowances, for the latent and sensible heat'loads, be definitely ascertained and used in the calculations to determine the total design load. BIBLIOGRAPHY * H. A. Mosher: When is complete air conditioning of the modem factory advisable? (.Heating, Piping and Air Condi tioning, June 1945, p. 305; July 1945, p. 385). . N. N. Wolpert: Air conditioning design conditions for vari ous industries (Heating and Ventilating, May 1949, p. 70; June 1949, p. 73; July 1949, p. 79; August 1949, p. 102). N. N. Wolpert: Air conditioning design data for commercial applications (Heating and Ventilating, February 1950, p. 68). ASRE Data Book Applications 1956-57 (American Society of Refrigerating Engineers). W. L. Fleisher: Air conditioning in the bakery (ASHVE Transactions, Vol. 37, 1931, p. 141). W. W. Reece: Air condition the bakery throughout (Heating, Piping and Air Conditioning, August 1936, p. 419). H. R. Gable: The air conditioning of processes in the bread bakery (ASHVE Journal Section, Heating, Piping and Air Conditioning, October 1947, p. 107). A. E. Stacey, Jr: Proper air conditions for the manufactur ing of confections (ASHVE Journal Section, Heating, Piping and Air Conditioning, October 1937, p. 640). J. Johnson and W. B. Ogden: Relation of Air Conditions to Tobacco Curing (Wisconsin Agricultural Research Bureau, 110:1-48, 1931). J. C. Siegesmund: Heating, air conditioning and insulation for penicillin production (Heating, Piping ana Air Condition ing, August 1944, p. 475). - Air Conditioning in Textile Mills (Textile Workers Union of America, CI.O., Research Department Technical Report). L. L. Lewis: Air conditioning for textile plants making and lining synthetic yams (RayonTextile Monthly, July, August, September 1930). *. P. L. Davidson: Refrigeration for textile mill air condition ing (Heating and Ventilating, May 1947, p. 57). C. G. Weber: Bureau of standards studies determine press room conditioning requirements (Heating, Piping and Air Con ditioning, March 1936, p. 137). Humidity in the pressroom (Heating and Ventilating, May 1932, p. 35). TtohmniHifying with gas in a printing plant (Heating and Ventilating, May 1935, p. 31). R. T. Williams: Air conditioning the newspaper plant (Heating and Ventilating, September 1937, p. 63). Air conditioning in the paper industry (Heating and Ven tilating, October 1935, p. 23). C. G. Weber: Air conditioning requirements of multicolor offset printing (Refrigerating Engineering, December 1936, p. 6). ' . C. G. Weber and L. W. Snyder: Reactions of lithographic papers to variations in humidity and temperature (V. S. Bureau of Standards Journal of Research, January 1934). C. G. Weber and M. N. Geib: The treatment of offset papers for optimum register (V. S. Bureau of Standards Journal of Research, February 1938). H. E. Ryerson: Silica gel air conditioning system serves rotogravure printing plant (Heating, Piping and Air Condi tioning, August 1937, p. 497). Air conditioning for clothing research laboratory (Heating and Ventilating, July 1943, p. 69). ' C. S. Leopold: Controlled air supply for supercharger, car buretor and engine testing (Refrigeratmg Engineering, August 1943, p. 85). . R. P. Dewey: Close machine tolerances possible through temperature control (Heating and Ventilating, April 1944, p. 60). F. M. Johnson: Moisture control by liquid absorption offers a useful air-conditioning tool (Heating, Piping ana Air Con ditioning, December 1938, p. 782). S. C. Rothman: The engineering control of some solvent hazards in war industries (ASHVE Transactions, Vol. 50, 1944, p. 319). D. C. Lindsay: Air conditioning as applied in theatres and film laboratories (Society of Motion Picture Engineers Trans actions, Vol. XI, 1927, p. 335). F. F. Stevenson: Industrial air conditioning (Heating, Pip ing and Air Conditioning, May 1948, p. 100; June 1948, p. 94). J. F. S&lsburg: Industrial air conditioning (Heating, Piping and Air Conditioning, July 1948, p. 88; October 1948, p. 93). C. S. Cave: Industrial air conditioning (Industry and Power, July 1945, p. 67; September 1945, p. 57). L. R. St. Onge: Reducing heat loads in industrial air condi tioning (Refrigerating Engineering, January 1946,' p. 35). Air, light, and sound controlled in Western Electric's new plant (Heating, Piping and Air Conditioning, November 1948. p. 79). . J. T. Browne: New IBM plant addition, Poughkeepsie, N. Y. (Heating, Piping and Air Conditioning, January 1949, p. 111). 6. E. Herb&cek: Photo studios need conditioning for both Srocessing and comfort (Heating, Piping and Air Conditioning, une 1949, p. 85). * A. D. Benjamin: Maintaining constant relative humidity (Air Conditioning, Heating and Ventilating, May 1955, p. 83). C. P. Strickland, Jr: Today's improved lemon storage (Re frigerating Engineering, December 1956, p. 43). . G. A. Warner: Laboratory climates automatically controlled (Refrigerating Engineering, June 1957, p. 50). H. E. Rex: Refrigerating equipment for the citrus industry (Refrigerating Engineering, November 1957, p. 43). R. S. Ash: Greenhouse climate control (Refrigerating En gineering, February 1958, p. 41). ' CHAPTER 51 CONTROL OF THE INDUSTRIAL ENVIRONMENT Heat Control of Industrial Work Areas, Thermo/ Standards, Control of Heat Exposures, Radiation Shielding, Roof Ventilators, loco/ Relief Methods, Physiological Aspects of System Design, Types and Requirements of Systems, Outlet Types and Design, Control of Contaminants ONTROL of the industrial environment is concerned of this process heat or to offset it completely by the usual C with the design and application of equipment for pro methods of comfort ventilation and air conditioning. In the viding the necessary conditions within industrial areas for design and operation of control measures it is frequently nec maintaining the efficiency, health, and safety of workers. This essary to accept some heat exposure in excess of simple com chapter includes a comprehensive list of the requirements fort requirements. for heat control and for control of gases and vapors, and dust The engineer must distinguish between the control needs and fumes. for hot-dry industrial areas and warm-moist conditions. In General ventilation may be relied upon in some cases to the first case, the process gives off only sensible and radiant control the industrial environment, as outlined in this chap heat without adding moisture to the air. The heat load on ex ter. Additional information on natural ventilation may be posed workers is thereby increased but the rate of cooling found in Chapter 11. If mechanical ventilation is to be used, by evaporation of sweat is not reduced. Heat balance may Chapter 20, Air Distribution; Chapter 21, Air Duct Design; be maintained although this will be at the expense, perhaps, Chapter 22, Fans; Chapter 24, Air Cleaning; Chapter 40, of excessive sweating. In the warm-moisture .situation, the Evaporative Apparatus for Heat Rejection; Chapter 41, wet process gives off principally latent heat. There may be Evaporative Air Cooling and Humidification; and Chapter no significant rise in the heat load on the worker but the 43, Automatic Control; will furnish information covering a increase in moisture content of the air will seriously reduce broad range of industrial design conditions. Chapters 13, 23, the heat loss by evaporation of sweat. The warm-moist situa and 38 provide data for mechanically cooled systems. Chap tion is potentially more hazardous than the hot-dry. ter 52, Industrial Exhaust Systems, should be consulted.for Examples of hot-dry work situations are seen around hot the design of hoods and their exhaust duct systems. For fur furnaces, forges, metal-extruding and rolling mills, glass ther information on estimating radiant heat conditions see forming machines, and the like. Typical of warm-moist oper Chapters 5 and 30. ations are laundries, dye houses, and deep mines where wa Information on globe thermometers and other instruments ter is extensively used for dust control. used to measure the industrial environment may be found in The industrial heat problem varies in magnitude with Chapter 44, Instruments and Measurements. More complete local climatic conditions. Solar heat gain and an elevated information will be found in References1 and* at the end of outdoor temperature will increase the heat load at the work this chapter. place but these contributions may not be very important Specialists in the field of industrial hygiene should be con compared with the locally generated heat of the process it sulted in case of doubt concerning the presence of airborne self. The moisture content of the outdoor air, on the other industrial hazards to health. Chapter 7, Air Contaminants; hand, is a most important climatic factor affecting hot-dry Chapter 6, Physiological Principles; and Chapter 8, Air work situations and on a moist summer day will seriously Conditioning in the Prevention and Treatment of Disease, restrict evaporative cooling. For the warm-moist job, in will be of help in establishing the atmospheric conditions contrast, solar heat gain and elevated outdoor temperature that should be maintAinwi around the worker. Local codes, are the more important, since, compared with the moisture ordinances, or state labor laws must likewise be observed, release on the job, that contributed by the outdoor air will particularly with regard to ventilation requirements for haz be of little significance. ardous trades. Comfortable conditions, if possible, or toler able conditions at least, are desirable because they are likely Thermal Standards for Industrial Work Areas to increase the efficiency and, hence, the output of workers. The majority of air-conditioning and ventilation installa tions in a typical industrial plant are concerned with the control of sensible, latent, or radiant heat. The work situations considered here are those in which the attainment of simple thermal comfort is not always prac ticable. The heat stress must be kept below the level of out right hazard,- but how much below? On what criteria should HEAT CONTROL IN INDUSTRIAL WORK AREAS the specifications for control be based? How should the standards be varied in recognition of the differing demands In certain industrial work situations there is considerable and work rates from one kind of job to another? What dif release of heat from the process equipment to the environ ferences exist between older and younger workers or between ment. It is not economically feasible to stop the escape of all workers with differing degrees of physical fitness? To what - 691 692 CHAPTER 51 1959 Guide extent can periods of beat exposure be offset by alternating periods of recovery? How is this expressed in terms of design of the control measures? These and other questions arise in the analysis of an industrial heat problem and must be con sidered by the design engineer and others before specifica tions are fixed As there is no single set of thermal standards applicable to all work situations, failure to give proper recog nition to the many facets of the problem can result in inade quate control, measures. . Biophysical Basis for Fixing Thermal Standards Under conditions of thermal comfort, the rate of internal heat production (metabolism) is just balanced by the rate of heat loss to the environment. This comfortable balance is Table 1.... Estimates of Energy Metabolism (M) of Various Types of Activity (VflkM apply for o 154 lb non. Bad do sol Jscftids rest pomes) Kind of Wart Activity M Btvjhr Light Work Sleeping.................................'.................... 250 Sitting quietly.......................'.................. 400 Sitting, moderate arm and trunk move- ments.................................................... . 450-550 (e.g., desk work, typing) Sitting, moderate arm and leg movements............................................. 650-650 (c.g., playing organ, driving car in traffic) - Standing, light work at machine or bench, mostly arms.............................. 550-650 Moderate Work Sitting, heavy arm and leg movements. 650-800 Standing, light work at machine or bench, some walking about................ 660-750 Standing, moderate work at machine or bench, some walking about........... 750-1000 Walking about, with moderate liftingor pushing................................................... 1000-1400 Heavy Work Intermittent heavy lifting, pushing or pulling.................................................... 1500-2000 (e.g., pick and shovel work) Hardest sustained work.......................... 2000-2400 maintained without active sweating, with optimum skin and deep-body temperatures and without unusual load upon the heart. At the upper limits of physiological tolerance to sus tained heat exposure, thermal balance may also be estab lished, but this is accomplished only, with active sweating, elevated and body temperatures, and accelerated heart rate. The limit is fixed by the maximum permissible degree to which these indexes of physiological strain--sweating, body temperature, %nd heart rate--can be safely elevated. For practical work situations in industry, the permissible limits of these indexes must be set below the absolute physio logical TTHfrima ' The thermal relationship between man and his environ ment is dependent upon four independently variable thermal. characteristics of the environment: air temperature' radiant temperature, moisture content of the air, and air velocity. These may combine in various ways, together with the rate of internal heat production, to create widely different degrees of heat stress. The need is to provide a rational hmaa for combining them into a single index that will predict the mag nitude of the heat stress and will serve also as a baas for fixing permissible limits of exposure. A start is made with the heat balance equation: where MdzRdzCmB-^-Ed: AjS . (1) M = metabolic rate. * R * rate of heat exchange with environment by radiation. C =* rate of beat exchange with environment by convection. B rate of heat loss from body in exhaled air. E = rate of heat loss from body by evaporation of sweat. AS = rate of change in heat content of body. Terms on the left side of Equation 1 represent the beat load; those on the right represent the heat loss together with the heat storage or withdrawal from the body. R and C are positive when the environmental temperature is above skin temperature and negative when below. ' In practice,' B and AS are of small magnitude compared with the others and can be neglected. For a condition of heat balance, therefore. Equation 1 may be written: M RC - (2) required rate of evaporation of sweat to maintain heat- balance. M can be measured by standard physiological techniques or estimated for a given work situation by reference to Table 1. On both theoretical and experimental grounds, R and C can be calculated with reasonable accuracy by means of standard equations of heat exchange: R = K^Artu. ~ t.) - 22(1. - i.). (3) where C - K. VvA(t. - f.) =* 2 - t.) (4) K, - coefficient of radiant heat exchange, Btu per (hour) (square foot) (Fahrenheit degree temperature differ ence). K, varies in value; depending on the mean radiant . temperature of the surroundings, l ' A, = radiation area of body, square feet. . At differs with body position and is around 0.8 of total body surface for a standing man. 22 K, X A, for average size man with moderately high mean radiant temperature,.!. . K, = coefficient of convective heat exchange, Btu per (hour) (square foot) (unit velocity) (Fahrenheit degree tempera ture difference). . A = surface area of body, square feet. 2 TM Ke X A, lor average size man. V -- effective velocity of air movement, feet per minute. tm = (black-body equivalent) mean radiant temperature of environment, Fahrenheit. l# a.ambient air temperature, Fahrenheit. ' l, * skin temperature, Fahrenheit! So long as there is no limitation on evaporation rate, the Control of the Industrial Environment 693 CHARTS FOR DETERMINING HEAT STRESS IOOX WETTED SKIN AT 95 F-0TU/HR' Example: Determine Hoot Shots Index for worker doing Eght arm work white standing at a bench. Metabolism 600 Btuh nWronmental condition*:' , Globe thermometer temperature Dry-bulb temperature Wet-bulb temperature Air vefodty no deg 90 F 75 F 100 fern Sotutfom Follow (he broken Knot from the globe thermometer temperature and from dry-bulb temperature to Ihefr interaction on above diagram C to read o hoof stress Index of 90. ' . Fig. I .... Flow Charts for Determining Heat Stress Index Values 694 CHAPTER 51 1959 Guide sweat output is automatically limited by the body to that amount which satisfies the required value of E. With re stricted evaporation, however, there is excessive sweating; the body becomes fully wetted and a matimum evaporative cooling rate is established which does not increase with fur ther sweating. This maximum evaporative cooling rate has been established experimentally and can be calculated by the equation: - m KtA V* *(P, - P.) = 10K* (P. - P.) (5) where . K. = coefficient of heat exchange by evaporation, Btu per (hour) (square foot) (unit velocity) (millimeter of mer cury vapor-pressure difference). 10 * K, X A for average size man, fully wetted. P, -- vapor pressure of water at skin temperature, milli meters of mercury. Pm -- partial pressure of water vapor in ambient air, milli meters of mercury. A combination of Equations 4 and 5 yields Equation 6 which is a statement of the maximum thermal conditions un der which man can maintain heat balance, giving proper recognition to internal heat production M, skin temperature t, and to all four of the thermal characteristics of the en vironment: ' if + 22(1. - 1.) + 2 y/vV. - I.) - 101"`(P. - P.) (6) Equation 6 provides a rational basis on which to construct a heat stress index and to establish thermal standards for different industrial work situations. Two physiological criteria are important in fixing the limit of sustained heat exposure: 1. The increase in body heat content must not exceed a cer tain leveL Practically, this is reflected in the rise in skin tem perature. This temperature may be limited to 95 F. 2. Thermal balance must be accomplished with a rate of sweating not greater than one liter per hour (equivalent to evaporative cooling of 2400 Btu per hr). Studies on young ac climatised subjects have shown that this maximum rate of sweating can be maintained over a workday without undue strain or physiological cost. The Heat Stress Index (ESI) proposed by Belding and Hatch1 makes use of these criteria together with the previous biophysical equations. A so-called standard young man, in good physical condition and acclimatized to beat, can safely engage in simple physical work over a normal eight-hour day in a particular thermal environment so long as his skin tem perature does not exceed 95 F and he maintains thermal balance with a sweat rate not exceeding 1 liter per hr. By definition, this degree of stress has an (HSI) value of 100 and is given by any combination of M + R + C which is balanced by Em., within their defined limits. For other situa tions where m is greater or less than (2400 Btu per hr), the value of (HSI) is proportionately different from 100: (HSD - 100 X EJ;'U00 (7) By using the globe thermometer temperature (see Chap ter 52) of the environment to represent the combined effects of mean radiant temperature and air temperature, the Heat Stress Index chart Fig. 1 has been constructed, to permit quick determination of (HSI) when U, t-*, and air - velocity are given. The procedure for finding (HSI) will be obvious by following the dash line in Fig. 1. The Heat Stress Index was developed from research ex perience with young men in good physical condition and well acclimatized to heat. Table 2 assigns suggested physiological meaning to (HSI) values above and below 100, for older men as well as the standard young man and, also, for various kinds of jobs which differ in their demands upon mental and physical effort. From these it becomes possible to select (HSI) levels appropriate to each work situation. The Heat Stress Index (HSI) differs from the Effective Temperature (ET) scale in the rational rather than subjec tive basis of its construction. Practically, the commonly recommended E7T = 80 F for heavy work at moderately high air velocity agrees very well with the (HSI) limit of 100 for acclimatized young men. In Fig. 2 are shown the combina tions of dry- and wet-bulb temperature (air and wall tem perature alike) for three different air velocities and three Toble 2 .... Evaluation of Index of Heat Stress (ndex of Heat Sins Pftydalogkai and Hygienic tapficcHoo* of 8-Hr Expasom to Variou* Heat Stnuti --20 Mild cold strain. This condition frequently exists in -- 10 areas where men recover from exposure to heat. 0 No thermal strain. +10 20 30 Mild to moderate heat strain. Where a job involves higher intellectual functions, dexterity, or alert ness, subtle to substantial decrements in perform ance may be expected. In performance of heavy physical work, little decrement expected unless ability of individuals to perform such work under no thermal stress is marginal. 40 Severe heat strain, involving a threat to health unless 50 men are physically fit. Break-in period required for men not previously acclimatised. Some decre ment in performance of physical work is to be ex pected. Medical selection of personnel desirable because these conditions are unsuitable for those with cardiovascular or respiratory impairment or with chronic dermatitis. These working conditions are also unsuitable for activities requiring sustained mental effort. 70 Very severe heat strain. Only a small percentage of the population may be expected to qualify for this work. 90 Personnel should be selected (a) by medical exami nation and (b) by trial on the job (after acclimati zation). Special measures are needed to assure adequate water and salt intake. Amelioration of working conditions by any feasible means is highly desirable, and may be expected to decrease the health hazard while increasing efficiency on the job. Slight "indisposition" which in most jobs would be insufficient to affect performance may render workers unfit for this exposure. 100 The maximum strain tolerated daily by fit, acclima tized young men. - Control of the Industrial Environment 695 different grades of work, all of which give (HSI) = 100. Points representing ET = 80 F.jvith an air velocity of 300 fpm are also shown for comparison. CONTROL OF HEAT EXPOSURES Measures for control of heat exposures will be treated un der the following headings: Control at Source, Local Exhaust Ventilation, Radiation Shielding, General Ventilation, Dilu tion Ventilation, Local Relief Ventilation. Control at Source . The magnitude of heat exposure can be reduced by insulat ing hot equipment, locating such equipment most favorably (in zones of good general ventilation within buildings or even outdoors), covering steaming water tanks, providing covered drains for direct removal of hot water, and maintaining tight joints and valves where steam may escape. This method is an obvious- one and requires no particular comment other than to emphasize the benefits to be derived from elimina tion of heat sources wherever possible. Local Exhaust Ventilation The natural convection column of heated air rising from a hot process may be captured by means of ventilated enclo sures or exhaust hoods and removed with a minimum of dilu tion by air from the surrounding space when local exhaust ventilation can be used. Chapter 52 provides detailed infor mation on the design 0f exhaust hoods and duct systems for local exhaust. Radiation Shielding In some industries, commonly referred to as the hot in dustries, there are many hot objects and surfaces such as furnaces, ovens, furnace flues and stacks, boilers, molten ma terial, and hot ingots of metal, castings, or forgings and, in consequence, the major environmental heat load is in the form of radiant heat. Since air temperature has no significant influence on the flow of radiant heat, ventilation is of no help in controlling such exposures. The only effective control is the direct one of decreasing the amount of radiant heat im- 696 CHAPTER 51 1959 Guide pinging on the exposed worker. This frequently can be ac complished by radiation shielding. Radiant heat exposures can be reduced by lowering the surface temperature of hot equipment by using insulation or water-cooled surfaces or radiation shields. Hot surfaces emit infra-red waves which reach all objects within visible range. This is true not only if the hot surface is a primary one such as a furnace wall, a high temperature stack, or a hot ingot, but also if it is secondary in nature, that is, one which is reradiating heat after receiving it by direct radiation from a high temperature source. It may well be that all surfaces in a shop or building are hot because of ra diant heat received from a few primary sources. Under these circumstances, the ventilation air is heated rapidly as it circulates through the building. The result is a very unsatis factory thermal environment, all stemming from the few pri mary heat sources. Consequently if the radiant heat load from these is reduced there will be a great improvement in the entire building. A shield is simply a sheet of material, opaque to the infra red waves (or essentially so), placed between the hot object such as a furnace, and the cooler surroundings. The closer it can be placed to the hot object, the greater will be the effective coverage. Essential to most shielding is the absence of physical contact and the presence of an air space between the hot object and the shield to avoid heating, of the shield by conduction. This is not a vital matter if the shielding ma terial has a low coefficient of emission for infra-red rays as does aluminum, for example. Under such circumstances, very little heat is radiated even if the shield becomes very hot. Radiation shields in the following 5 forms are very effec tive: 1. Sheets of reflective metal or insulating board, semi-permanentiy attached to the hot equipment (such as furnace buck stays) or arranged as semi-portable floorstands. 2. Aluminum foil-faced cloth curtains raised or lowered on spring rolls. 3. Transparent shields, including heat reflective* tempered plate glass, reflective metal chain curtains, and close mesh wire screens. These have lower efficiency than opaque shields in items 1 and 2. 4. Water-cooled shields for absorbing the heat. 5. Reflective garments, such as aprons, or in the form of a sandwich in cases of continuous front and back exposures. For continuous wear the apron or sandwich width should be limited to from 14 to 18 in. in order to assure adequate continuous ride openings for air circulation and body ventilation. In addition, gauntlets and face shields are particularly applicable to opera tions such as the pouring and casting of hot metal. Supply houses dealing in safety clothing for industry offer suitable light-weight flame proofed foil-faced cotton drill or denim of excellent reflectivity. For repairs inside hot coke ovens and in dustrial furnaces, a complete suit is available using forced ven tilation from a small blower or a compresed air source. These suits may be made of asbestos cloth faced with a reflective metal in atomised form. If the shield is a good reflector, it will remain relatively cool in the presence of severe radiant heat. This reflectivity is a surface characteristic and is not dependent on thickness. A thin foil is effective. Tinplate, stainless steel, and ordinary flat or corrugated aluminum sheets are efficient and longlived. Foil-faced plaster board, though less durable, gives good reflectivity on one side. Since the best radiation shields are effective reflectors of infra-red rays, they must be used intelligently lest a radiant heat load merely be transferred from one place to another. The objective is to have the shield reflect the radiant heat back to the primary source where it may be removed by local exhaust. However, unless the ' shield completely surrounds the primary source, some of the infra-red energy will be reflected into the cooler surroundings and possibly into an occupied area. It is imperative, there fore, to study well where the reflected heat will go before shielding is installed, to avoid merely getting rid of the prob lem in one area by transferring it to another. GENERAL VENTILATION General ventilation, which involves sweeping of the space, occupied by workmen and process heat sources with large quantities of outdoor air, may be used to limit the tempera ture rise within the space, if the outdoor air itself is not too hot. The method is particularly suitable for cases where the heat sources are spread over the entire area, and for the re moval of solar heat from the space. Dilution Ventilation . The principles of dilution ventilation furnish the basis for the design of the general ventilation system. The amount of air which must be circulated can be estimated as: where H = Heat to be removed from the space,'Btu per hour. At -- temperature rise of the air, Fahrenheit degrees. All heat sources such as furnaces, electric motors, ovens, and kilowatts of lighting should be tabulated to give the total heat output in Btu per hour (See Cooling Load Cal culations, Chapter 13). The amount of air to be exhausted is a function of the total amount of heat and the permissible air temperature rise which, in practice, may vary from 10 up to 40 deg, depending on many factors such as roof height, nature of work being done, and magnitude of heat release. Advantage should be taken of the chimney effect of the heated air within the space by introducing the diluting air near the floor of the space and discharging the heated air as near the top of the structure as possible, regardless of whether natural or mechanical exhaust ventilation is used. Since the workmen ordinarily operate near floor level, the entering air temperature should be within acceptable limits as outlined earlier in this section. The leaving air temperature will have its effect on workmen through the radiant heat emitted by the upper parts of the structure which are heated by the air. A higher leaving air temperature can be used with a high than with a low ceiling, since the ceiling contribution to the mean radiant temperature will be less for the taller structure. Roof Ventilators ' Roof ventilators are basically heat escape ports located in the high section of a building and properly enclosed for weather-tightness. Stack-draft effect plus some wind induc tion are the motive forces for several common designs of con * tinuous ventilators and round ventilators. The latter can be equipped with fan barrel and motor, thus permitting gravity operation, or motorized high capacity operation, at will. Two other main designs are available: one is the low-type ventilator which consists essentially of a stack fan with a rainhood; the other contains a stack fan with a split butter fly closure that is floated to open position by the discharge air stream and is self-closing. Both employ mimimnm enclo sures and have little or no gravity capacity. Various types of roof ventilator? mnv be listed in diminish- Control of the Industrial Environment 697 ing order of temperature differential and heat-removal ca pacity. Next to chimneys and stacks, the continuous ventila tion monitor is most effective for removal of substantial and concentrated heat loads. This may be in the form of an ele vated length of roof ridge with extended overhang and no rain louvers. Such structures are commonly employed over open hearth furnaces and soaking pit buildings but, in prac tice they give uncertain performance. A more efficient type is a streamlined, watertight monitor constructed of noncor rosive metals or protected metals. Its capacity increases with wind velocity and it can be readily closed in winter to con serve building heat. Both types have tremendous capacity and are limited only by roof area and proper relation of low- level air inlets. Next in capacity are the (1) round gravity or'windband ventilator, (2) round gravity type with fan and motor added, (3) low-hood powered ventilator, and (4) vertical upblast powered ventilator. Popular modifications of these include the rotary type and the turbine ventilator. Minimum-capacity ventilators of the gravity type are ap plicable to warehouses with light heat Loads, and to manu facturing areas having high roofs and light loads. Non mechanical ventilators are desired here because the wide spacing makes electrical wiring and maintenance of fans and motors a matter of concern. - Streamlined continuous ventilators must be able to operate effectively in the absence of mechanical power. While it is difficult to predict performance accurately, it can safely be said that efficient ventilator operation is generally obtained when difference in elevation between the average air inlet level and the roof ventilation is not less than 30 ft and the exit temperature is 25 F deg above the prevailing outdoor temperature. See Chapter 11, Infiltration and Ventilation. Under these conditions and with a wind velocity of 5 mph, the ventilator throat velocity will be about 375 fpm. It will thus remove 10,000 Btu (per hr) (sq ft of throat area): 25 deg X 1.08 X 375 cfm = 10,000 Btu *" To insure this level of performance it is essential that suf ficient low-level openings be provided for the incoming air; otherwise the gravity ventilator becomes starved for air and capacity falls off. The manufacturers recommend 250 fpm to 450 fpm inlet velocity. Lack of adequate inlet area is the most common cause of failure of gravity-type roof ventila tors. A positive supply of air to insure direct ventilation around the hot equipment may be necessary within buildings of considerable area where the external wall inlets are remote from the equipment. A decision between gravity and mechanical ventilators may be difficult to reach. The electrical power required for fan operation may be a deterring factor but this is offset'by the advantage of constant ventilation capacity given by fan operation. Mechanical ventilators will also function despite inadequate fresh air inlets. In many cases there is justifica tion for a mechanical supply (make-up air) which will posi tively supply air to the work zone. LOCAL RELIEF General The methods required for general ventilation of industrial areas have been described. Such ventilation may have to be supplemented, or in some cases replaced by local ventilation in large industrial areas having substantial heat loads, high ceilings, and scattered work stations. Provision must be made for local relief, to proride tolerable working conditions around the several operations where the heat loads are concentrated. The methods indicated to be described for local relief are based on the assumption that exhaust ventilation, radiation shielding, equipment insulation, and possible changes in process design have been fully utilized to minimize the heat loads. Methods of Providing Relief Relief in local industrial work areas, may be provided by any of the following three methods (or a combination of the three): 1. Provide a complete enclosure around the worker with separate ventilation in order to maintain cooler working condi tions. This may be in the form of a control room, small shelter booth, or ventilated crane cab. In effect, this is "localised" gen eral ventilation, differing only in the conditions of air tempera ture, humidity, and motion required. 2. Surround the worker with a relatively cool atmosphere by a direct supply of air introduced at a low level over a small area of the plant. In such cases we are not concerned with the temperature at higher levels in the space so long as adjacent structures do not become hot and thus return radiant heat into the work space. . 3. Direct a high-velocity air stream at the worker to increase the evaporative cooling effect. This method, commonly called spot cooling will incorporate varying degrees of Method 2, de pending upon the number of employees and the distribution of the work stations. Method Number I, in the form of a work station enclosure, is the most desirable because it permits complete control of the environment. The second method is effective in large areas with many work* stations, such as machine shops and asembly lines. The last method is used to provide spot coolr ing in large spaces where scattered work stations and lo calized sources of heat make it highly impracticable to main tain a tolerable environment throughout the building. Physiological Aspects of System Design Two different situations in respect to heat load are encoun tered: (1) where radiant heat sources are not important, and (2) where radiant heat sources are important. These two situations must be treated differently in design. Where Radiant Heat is Not Important. Where no impor tant sources of radiant heat are located within or close to the work area, it is only necessary to introduce the relief air into the work space in such a way as to displace the hot air and thus surround the worker with an acceptable atmos phere, consistent with his own needs. Where Radiant Heat is Important. Where important sources of radiant heat are present and cannot be entirely controlled by radiation shielding, the air supplied for relief must do more than simply displace the hot air. It must also provide convective cooling to offset the radiant heat load. This requires that the air be supplied at a lower temperature and with sufficient velocity. Contrariwise, if the temperature of the relief air exceeds skin temperature, a convective load - is added to the radiative load and these, together with the metabolic heat must be removed by evaporative cooling. As the temperature of the air impinging on the worker rises above the skin temperature, a critical point is approached where too high an air velocity will add to the body heat load and too low a velocity will fail to evaporate the sweat, and thus fail to provide the maximum evaporative cooling effect.*- * The level of air motion provided at the work station should be low, approaching normal room velocities, or about 698 CHAPTER 51 1959 Guide 50 fpm for light activity in a fixed position, and- particularly when the individual is seated at a desk or bench. The maxi mum velocity around the worker should not exceed 200 fpm for continuous exposure. With a high work level and inter mittent exposure (relief stations), velocities of 1000 to 2000 fpm have been used successfully. Great care must be exercised in using such high velocities, however, to avoid the undesirable effects of air at high temperature. Ordinarily the temperature of the air supplied to the worker for convective cooling should be about SO F. Evapo rative cooling ventilation systems will usually provide this. Preferably, the air should be directed to the front and torso of the body. Impingement on the back of the head, neck, and shoulders should be minimised. The supplied air may require tempering in winter to raise it to an acceptable temperature. However, in areas of high heat load, the tem perature of the air supplied during the winter may have to be lower than room temperature to provide adequate relief for the worker. . People vary considerably, in their tolerance to air motion, temperature, and humidity, and this tolerance varies with the season. It is essential, therefore, that the air supply out lets for most local relief ventilation systems be adjustable in direction, and permit reduction in outlet velocity. A level of air motion which feels comfortable and refreshing in hot weather may fed disagreeable and drafty in the winter. Types and Design Requirements of Systems The supply air can be provided by local man-cooling fans; by outdoor air introduced directly or after dehumidification or cooling (evaporative or mechanical); and by combinations of outdoor and recirculated air either direct or after con ditioning, as required. Local man-cooling fans should be used with caution other than in light beat-load areas where the ambient temperature is below the kin temperature. In particular, where there is an elevated ambient temperature with or without high radi ation load, the high velocity may add considerably to. the convective heat load and thus seriously increase the demand for sweating and evaporative cooling. A relief system employing outdoor air is to be preferred over-man-coolers and will provide excellent relief in many industrial areas. However, when the outdoor air temperature exceeds the skin temperature, the direct supply of outdoor air is obviously reduced in effectivenes. Such a system is properly used only in geographical areas where the periods of hot weather are of short duration. In geographic areas where outdoor humidities do not exceed 50 percent relative humidity at high daytime tem peratures an evaporative cooling system offers greater relief for the worker in that the discharge air temperature can be lowered (within five degrees of the wet-bulb temperature) to obtain adequate convective body cooling. The sensible heat gain by the discharge air (through mixing) in a properly designed system will be sufficient to reduce the relative hu midity (and vapor pressure) of the supply air and thus per mit the necessary evaporative loss from the worker's skin. Generally the supply of evaporatively cooled air should not exceed 20 to 50 percent of the total ventilation through the building. So limited, the relative humidity will be kept low enough to avoid distress to the workers and rusting of equip ment under most weather conditions in the United States. For information on the design of evaporative cooling systems, see References 5 and 6 and Chapter 41. An air supply with mechanical refrigeration offers the greatest relief. Such systems are expensive in first cost and this has retarded their use. However, air supply with me chanical refrigeration is finding greatly increased use in pre cision work and testing areas, in areas requiring constant ambient conditions for product uniformity or control, and where the increased efficiency of the worker is reflected in a reasonable return on the investment. It is essential that the outdoor air, (with or without cool ing) be brought as directly as feasible to the proximity of the work station. Impingement upon hot equipment or mixing with hot ambient air should be minimized. Supply ducts passing through hot areas should be insulated. The use of aluminum ducts will minimize heat gain from radiant sources. For large work areas provided with a high rate of ventilation the local relief can best be obtained by locating the outlets as close to the floor as posible, consistent with the work and structural interferences. ' - Design of Outlets for Local Relief In the design of outlets foT local relief it is of great im portance to consider the following: location; discharge veloc ity, discharge volume, and control of direction. The influence of these items will be discussed in the paragraphs which follow. Location. The outlets should be kept as close to the worker as posable in order to minimize mixing with the warmer air in the space. In most areas the outlets can and should be brought down to the 7-ft level. Outlets at floor level can be used with success in many cases. Discharge Velocity. The discharge velocity may be as high aa necessary to obtain the desired velocity at the work station, as outlined above. Outlet velocities of 3000 to 4000 fpm may be necessary for remotely located outlets. Velocities of 1000 to 2000 fpm are the most frequently used for low outlets (at the 7-ft level). When the supply air is cooled, the velocity through an outlet directly at or over the worker must be kept low (around 50 fpm). It should be kept in mind that these recommended velocities are for conditions of max imum heat load. For more moderate weather and ambient conditions the workers will desire to reduce the velocities. Outlet dampers for velocity control (in the direction of the worker) should always be provided. The control must be designed so as not to reduce the ventilation for the space. Discharge Volume. The outlet volume required will vary widely, depending upon whether the system is designed to provide highly localized spot cooling or is to provide general ventilation throughout a sizeable work area. Generally 1500 to 2000 cfm per station will be adequate for moderate loads, and 3000 cfm per station for higher loads such as at hot metal furnace stations. With remote outlets large air volumes are required to insure adequate relief because of the mixing of the supply air with the wanner surrounding air through which it is projected. The air stream from a large outlet will mnintjiin an appreciable core of air at the original supply air temperature for a considerable distance from the outlet. Small outlets and slot outlets have small cores which are rapidly dissipated through induction. In small enclosures or semi-enclosures (shields against radiant heat, for instance) perforated panel supply outlets are very effective for me chanically cooled installations, because of their low induction characteristics. For further information on outlet design and the throw and induction characteristics, see Chapter 20. Control of the Industrial Environment Control of Direction. With very few exceptions, direc tional outlets are necessary in order to maintain ventilation or make-up air to the space even when the workers do not wish to have the air directed into their work zones. In this - way, the air can be directed down in the summer when it is needed, and up in the winter for ventilation, heating, and make-up purposes. It will be possible, too, to direct the air toward one or another work station, as needed. From the production standpoint, directional control may be necessary to direct the relief ventilation so as not to disturb the product or upset the performance of local exhaust hoods. Types of Outlets for Local Relief A few of the different types of outlets are shown in Fig. 3. In most cases, volume control is highly desirable. Directionaliring and damper control should be designed for easy ad justment from the floor by chain, sash cord, or pole. Where Fig. 3 .... Directional Outlets for Spot Cooling a constant total volume of supply make-up air must be maintained, an outlet similar to E will permit volume adjust ment to the work zone without reducing the total air supply to the building area. A double deflection grille is available with gang-operated, horizontal face bars (similar to D) to accomplish the desired objective by directing the air down to the work zone or toward the ceiling. Such a grille could be installed on outlet F. Outlets A, B, and C could be used without dampers for these applications. An inexpensive means of supplying summer relief air is shown in G. Easilyadjusted diffusers, which will provide a flat or down-blast air discharge pattern, are available. Where overhead installations are not possible because of structural interferences or other difficulty, outlets near the floor may be used. These may be in the form of grilles located 699 in pilasters, control panels, tables, equipment, or in the floor itself. Such outlets have been quite successful in welding and foundry areas and at the work locations in kitchens. CONTROL OF ENVIRONMENTAL GASES AND VAPORS, DUSTS, AND FUMES In general, the systems for the control of these atmos pheric contaminants in industrial plants will be of three types: 1. Local exhaust systems will be indicated where the con tamination originates at concentrated areas and is characterised by low or imperceptible air motion, or where the contaminant is a dust, mist, or fume requiring a capture velocity exceeding 25 fpm. Design of this type system is discussed in Chapter 52, and will not be further treated in this chapter. 2. A system employing the dilution method will usually be indicated where the contamination originates at scattered points dispersed generally throughout the area. 3. Combination of local exhaust and dilution methods is often economical, since well designed exhaust hoods or openings, re moving from the space that portion of the contamination load which is susceptible to such treatment, will often reduce greatly the air volumes required for dilution purposes. The choice of the type of system should be made on the basis of economic comparisons. Design of Dilution Systems The first step in the design of a system employing the dilution method is to determine as exactly as possible the nature and extent of the contaminating load. This will often be difficult, and may require construction of pilot production models. Often, however, the required data will be available from production records, showing the weight or volume rate of loss of the contaminating agent to the atmosphere, or it may be estimated from parallel operations in other plants, or by applying experienced engineering judgment. However ob tained, the determination of the nature and magnitude of the contaminating load is an indispensable step in the proper design of the corrective system. Designs based on number of air changes per hour, or other rule-of-thumb methods, are hopelessly inadequate, and lead either to unsuccessful opera tion or to excessive and unnecessarily high cost of installation. 1. Gases and Vapors. Once having established the nature and magnitude of the contamination load, it is rarely necessary to completely remove contaminating agents from the atmosphere. For cases involving diffusible vapor or gas contaminants, maxi mum allowable concentrations (MAC) of commonly encoun tered gases and vapors have been established, and these data are tabulated in Chapter 7. From these data, and the previouslyestablished rate of addition of the contaminant to the space, the volume of air required to dilute the addition to a tolerable level can be calculated by the equation: Qm = v` (MAC)-(SAC) (9) V where Q " quantity of air circulated, cubic feet per minute. Q, ~ rate of generation of contaminant, cubic feet per minute. ' (MAC) -- maximum allowable concentration, ppm by vol ume. ` - (SAC) = concentration in supply air, ppm by volume. The rate of generation of the contaminating vapor will often be available as a weight or volume of liquid evaporated into the space per unit time. These may be converted to the units of Equation 9 by applying the principle that a pound-mol of a i 700 CHAPTER 51 1959 Guide gas or vapor will occupy approximately 359 cu ft at standard pressure and temperature. Thus, . cfm (vapor) = -- X 359 X -- (10) where ' W = rate of generation of contaminant, pounds of liquid solvent per minute. M,, ^ molecular weight. ` t " air temperature, Fahrenheit. - A special case occurs where local concentrations of solvent vapors at the breathing tone, resulting from concentrated sources of contamination, are intolerably higher than the aver age design concentration when using dilution methods. Data are available for calculations, but involve many assumptions re garding boundary conditions, such as convection area and ran dom air movement in the vicinity. 2. Dusts and Fume*. Maximum allowable concentration of various dusts, fumes, and mists are also tabulated in Chapter 7. However, the dilution method as a means of treating particulate contaminating agents should be used with care, since the allow able air movement in spaces will ordinarily be lower than the capture velocity required for such particles. Exhausting at the source (see Chapter 52) will generally be the recommended treatment for these particulate contaminants. REFERENCES 1 Encyclopedia of Instrumentation for Industrial Hygiene (Publications Distribution Service, University of Michigan). * Industrial Ventilation (American Conference of Govern mental Industrial Hygienists). ' H. S. Belding and T. F. Hatch: Index for evaluating heat stress in terms of resulting physiological strains (ASHAE Trans actions, Vol. 62, 1956, p. 213). 4 G. F. Baines, Jr. and T. F. Hatch: Industrial heat exposureevaluation (Heating and Ventilating, November 1952, p. 93). *B. R. Small: Heat relief in industry (Iron and Steel Engi neers Magazine, April 1952). 'Evaporative cooling--a symposium (ASHAE Journal Sec tion, Heating, Piping and Air Conditioning, August 1955, p. 141). CHAPTER 52 INDUSTRIAL EXHAUST SYSTEMS Elements of Exhaust Systems/ Hoods or Enclosures, Capture Velocities, Air Volume, Exterior Hoods, Special Exhaust Require ments, Exhaust of Hot Processes, Induced Air Flow,- Duct System Design,- Calculations; Construction Specifications, Materials, Details/ Air Flow Producing Equipment,- Air Cleaning Equipment/ Make-up Air/ Maintenance of Performance/ Materials for Corrosion Resistance . N. industrial plants, some type of exhaust system de I signed to collect and remove dusts, fumes, mists, vapors, and gases is installed to protect health and safety of industrial personnel, promote worker efficiency, salvage usable material, or improve plant housekeeping. This chapter will not include consideration of systems similar in design, but used to convey heavy loadings (100 or more grains per cu ft) of materials. Definitions of various air contaminants, their particle sizes, maximum allowable con centrations, and upper and lower explosion limits are included in Chapter 7, Air Contaminants. ' Exhaust systems are 'extensively used for control of contaminants from: 1. Mechanical cutting and abrading operations including abra sive blasting and rock cutting. . 2. Fuel-burning and exhaust gas producing operations. 3. Molten materials handling operations. . 4. Welding, burning, and soldering operations. 5. Fiber handling operations. 6. Volatile and gaseous material handling operations. 7. Chemical processes. ' Local exhaust systems should be considered whenever possible rather than. general ventilation methods which allow contaminants to be dispersed within the workroom. The former provide more positive control, as well as a great reduction in exhaust volume handled, thereby re ducing the cost of air cleaning equipment required. booths, sidedraft or downdraft hoods (with or without side shields) have been developed from this complete enclosure concept. Openings in hoods are kept to a min imum gjgfl and are placed away from the natural path of the contaminant travel when possible. Doors should be provided for inspection and maintenance when needed. Capture Velocities and Air Volume Exhausted Only after the hood design has been determined can the exhaust volume requirements be calculated. With en closures, volumes are calculated from the known open area of the hood and the selected capture or indraft velocity suffi cient to prevent outward escape. Usual capture velocities for typical operations are listed in Table 1 and refer in the case of remote hoods to the air movement required at the zone of air contaminant generation. Required capture velocities for any operation will vary with the magnitude of the air volume handled, with uncontrolled air movement in the area, and often with the location of the process or operation and size of the workroom. Large remote hoods exhausting large air . volumes will provide effective control at lower maintained capture velocities than will small remote hoods handling lower exhaust volumes. A hood at one end of a small narrow room with air supply at the opposite end will provide control with a lower capture velocity than that required from the same hood in a large room where no ELEMENTS OF EXHAUST SYSTEMS An exhaust system consists of (1) hoods or enclosures at sources of air contamination, (2) branch and main ducts through which an air stream transports the con taminant to air cleaning devices or to the atmosphere, (3) air moving equipment to produce the required air flow into hoods or enclosures, and (4) air cleaning equip ment when required. See Chapter 24, Part II, for discus sion of types, applications, and principles of operation. HOODS OR ENCLOSURES 1 w The most effective hood or enclosure is one that will require the minimum exhaust volume for effective con taminant control. The design must therefore be based upon a knowledge of the process or operation for which control must be obtained. The more complete the en closure, the more economical and effective will be the installation. ' Many designers give first consideration to a hood com pletely enclosing the operation and then provide necessary access and working openings. The familiar hoods, such as Table 1 .... Minimum Air Velocities Required at Point of Origin to Capture Contaminant Effectively Minimum Condition of Generation Cepftu* of Contomineral Veiodtf, Fpm Process Released without 50-100 Evaporation of vapors, exhaust noticeable move from pickling, washing, de ment greasing, plating, welding, . etc. Released with low 100-200 Paint spraying in booth; inspec velocity tion, sorting, weighing, pack - aging, low speed (less than 200 fpm) conveyor transfer points, mending, mixing, barrel fill ing. . Active generation 200-500 Foundry shakeout, high speed (over 200 fpm) ' conveyor transfer points, crushers, screens. Released with great 500-2000 Grinding, tumbling mills, abra force sive cleaning. 701 702 CHAPTER 52 1959 Guide perceptible air flow will exist except in the immediate area of the hood. Exterior Hoods Where enclosure of the process is impracticable, the air flow pattern in front of the hood must be such that capture velocities required to convey the contaminant to the hood opening will be maintained in the area of contaminant generation. The method for determining, approximately, the quan tity of air that must be nrhaiigteH from an unobstructed hood, without flanges, to produce design capture velocities at the point or origin, is given in Equation 1: Q - VZ(IQX* + A) (1) tchert Q -- quantity of air exhausted, cubic feet per minute. Vz " air velocity at X-distance in feet from the hood and and on the center line of the hood, feet per minute. X = distance along the hood center line, from the face of the hood to the point where the air velocity is Vz feet per minute, feet. A -- area of the hood opening, square feet. Fig. 1 shows lines of equal velocities (velocity contours) for a rectangular hood opening with a side ratio of one- half. The velocities are expressed as percentages of the velocity at the opening. Studies have established the principle of similarity of contours which states that the positions of the velocity contours for any hood (when the contours are expressed in terms of the average velocity at the hood opening) are purely functions of the shape of the hood. Extensive studies*- "* " have revealed variations in values-of such velocity contours for long narrow slots and for hoods with one or more planes shielded against air flow. For smaller hoods, flanges which are usually 3 to 6 in. wide surrounding the hood opening usually will improve Table 2 .... Summary of Exhaust Rates Required with Common Types of Exterior Hoods Applied ' to Cold Processes Onlyu X-Drsfonce Inches Simple Opening, with or without Flange or Toper, faat No Plano Flanking Openingj* Simple Redungtiar Open ing flanked by Plant Parade! to Axis* fcshaujl koto Cfan Exhaust Rat* Cfm 2 4 6 8 10 12 15 18 21 24 30 36 42 48 ' 25-75 50-100 100-200 200-400 300-600 400-800 600-1200 900-1500 1200-1800 1500-2200 2500-3500 3000-4500 4000-6000 5000-7000 25-50 50-75 75-150 150-300 200-400 * 300-600 400-800 600-900 700-1000 800-1200 1200-1800 1500-2200 2000-3000 2500-3500 1 X-Disfonce Single dolt flanked by parade! plane on which containu>at)on process occtrre For X-distanc* fee, widlh of plane) always less than length of slot* Less than 2 ft More than 2 ft Exhaust rate 125 to 150 cfm per sq ft of plane area. Exhaust rate 75 to 125 cfm per sq ft of plane area. * Refers to simple hood opentnc that performs is acoordsace with Equation I. V Refers to hood hsriof complete fleahint plane parallel to exts which pre vents flow of sir from bsif of norma) air supply zone, sod performs in aeeordem with the equation. Q - Vj (SX* + X). Example; reetaatuUr hood openint rat- tat oa bench top. iMludee (intis slots, eo flanked, for X-datsoce treater then H slot length. . * If X-distence is crater than H slot lentth, consider it ss a am*te openint flanked by a plane (see upper ri(ht oolumn). With exhaust rate divided between S slots, an additional safety factor it provided. From plsal and Pteeat VtntHatin, by W. C. I* Hetaoon (Industrial Press, New York). Fig. 1____ Velocity Contours for Rectangular Opening with a Side Ratio of One-Half. Contours ore Expressed as Percentages of the Velocity at the Opening the air flow in front of the hood and will reduce the. air volume required to provide desired capture velocities by as much as 25 percent. < The exhaust volume calculated for an exterior hood by different designers may vary greatly due to their selection of different empirical design velocities. Usually capture ve locity design values are in the 50 to 200 fpm range. The rates calculated for large exterior hoods may become needlessly large if the capture velocity is selected blindly. Whether on not an individual particle or a rttmUI wisp of gas or smoke in motion away from the hood is captured before it escapes from the rone of in fluence created by the hood is determined not only by the specific air velocity (design capture velocity) at the im mediate point of contaminant release but also by the depth of the moving air curtain it must traverse before it gets beyond the influence of the hood. The capturing force of the air flow in front of any exhaust hood is the summa tion of all the separate velocities beyond (away from the hood) the point of contaminant release multiplied by the distance through which each velocity acts; i.e., force Industrial Exhaust Systems 703 times distance, the force being a function of the velocity. For large hoods, or more accurately for large exhaust rates, the depth of the rone of influence is much greater than for small exhaust rates and, also for the former, the distance between successive velocity contours is greater. Further effectiveness for larger volumes can be obtained where the air supply source produces a sweeping flow toward the roue of contaminant release. Table 2 presents design data by Hemeon4 applicable to exterior hoods employed for exhausting contaminants originating in a cold process only. These values are based on Equation 1 wherein varying values of Vz have been employed according to a scale that takes account of ve locity depth factors discussed in the preceding paragraph, and where X-distance is taken as the distance from the hood face to the point where any high velocity air cur rents engendered by the contaminating process itself have expended their energy. In addition, the ranges of exhaust volumes which have been found satisfactory in practice for many operations are reported in Table 3. These data provide a means of checking the calculated rates for specific applications. The exhaust rate for satisfactory control of hot proc esses can be kept at a minimum by enclosing the hot processes as completely as possible and exhausting from the top of the enclosure. Low canopy hoods rank next to enclosures in economy of air flow. High canopy hoods must handle greatly in creased amounts of air over that in the heated stream - itself, in order to receive and dispose of the air entrained by the convection column from far below. Where lateral exhaust ventilation must be employed, the air flow toward the hood has to overcome the tendency of the heated air to rise and also must sweep it into the hood. Consequently, the required exhaust air flow is very much larger than for hoods that simply capture the upward flow of heated air. A combination of an exhaust hood with a positive jet of air blown across the top of the equipment and directed into the hood may be required above large pieces of equipment. Hemeon has suggested" design' Equations 2 to 6 which follow for various types of hoods. . Equation 2 is suggested for estimating the flow of heated air rising from the top of a hot body: . SPECIAL EXHAUST REQUIREMENTS It is important to note that certain operations may require exhaust volumes in excess of the quantities based on design data from Table 1 and Equation 1. Typical reasons for increased ventilation rates include: 1. Induced air flow caused by the thermal or stack effect from sources of extreme heat. ' 2. Induced air flow caused by falling granular material in large quantities through considerable height, or* by internal rotating parts such as some types of crushers, knives, or mac- erators. (See discussion in later section Induced Air Flow and Table 4.) * 3. Exhaust volumes insufficient to dilute mixtures of com bustible vapor and air to les than 20 percent of the lower ex plosive limit of the combustible. " 4. Room air currents caused by cross drafts, spot cooling, motion of machinery or operators. Cross drafts are of great significance in the exhaust of hot processes with high canopy -hoods. 5. Design volumes, especially in the case of excess heat con trol and solvent vapors, may be based bn dilution systems where exhaust volumes are selected to keep contaminant concentra tions below design levels. See Reference 13, Chapter 7. 6. Local or State regulations may. specify larger exhaust vol umes for specific operations. ' . Exhaust volume requirements for many specific opera tions have been listed in Tables 3, 5, 6, and 7. where 5,-28 -VB. A.' I, (2) = air flow rate at upper limits of hot body, cubic feet per minute. Ap *r cross-sectional area of air stream at upper limits of hot body, square feet. I* -- height of hot body, feet. B, =* convections! heat transfer rate, Btu per minute. The area A, may be approximated from the dimensions of the hot body. For horizontal rods, the width of the stream is practically the diameter of the rod. For vertical planes, the air stream appears to thicken at an angle of 4 to 5 deg with the plane. For horizontal planes, the area of the air stream may be' taken as equal to the area of the plane itself. In the case of horizontal plates, in the absence of' better experimental information, U may be taken as equal to the horizontal diameter. Chapter 5 furnishes informa tion which may be used in estimating the heat transfer rate H. The flow rate, q, of heated ait entering -the hood after turbulent mixing and dilution have taken place may be approximated for low canopy hoods above horizontal sur faces and where no heat from steam is involved, as Exhaust of Hot Processes . In designing local exhaust hoods for hot processes, it is necessary to estimate the rate of delivery of hot air to the hood by the convection column. The exhaust ca pacity should exceed this by an amount sufficient to create a velocity in the excess air flowing into the envelope sur rounding the convection column that will prevent escape of the heated air at the edges of the hood. Unless distances from the heat source to the receiving hood are small (possibly under 3 ft), the quantity of heated air entering the hood is increased substantially by the induction and turbulent miring of large quantities of room air as the distance above'the heat source increases. Unless the ex haust hood can handle this total volume, spillage of con taminated mixture will occur. where q. - 5.4 A* lt (AI)W4 (3) At " surface area of hot body, square feet. At " the temperature difference, hot body to room air, Fahrenheit degrees. Similarly, where the heat is furnished by steam from a tank of hot water, - 5. -- 290 A. \/UG (4) where Q =* the rate of steam formation, pounds per (square foot water surface) (minute). (Continued on p. 707) . 704 CHAPTER 52 1959 Guide Table 3 .... A Guide to Ventilation Rates for Typical Industrial Equipment State or Local Bagi/Iatioiu Should bo Consulted and Foflowod Where Higher Ventilation Rate* ore SpodAed Operation Type of Hood Vniilafion Air Flow Jtutd Tramporl Velocity Fpm RoaMfit end Reference* Abrasive blast rooms Tight enclosure with air 60-100 fpm downdraft Gong - (sand, grit, or shot) inlets (usually in rooms of tunnel proportions roof) 100 fpm crossdraft) 3500 Ref- 8. Many codes specify minimum downdraft of 80 fpm Abraaiveblast cabinets Tight enclosure with 20 air changes per minute but access openings not less than 500 fpm through all openings 3500 Ref. 14 Asbestos: Carding Spool winding Enclosure Local Hoods 800 cfm per machine 50 cfm per spool 3000 3000 Ref. 2, 16, 17. See references for details and other opera tions _ Bagging: Open Bag Top Booth or enclosure (pro Paper bags--100 cfm per sq ft vide spillage hopper) open area Cloth. bags--200 cfm per sq ft ' open area 3500 3500 Ref. 18 Barrels--Drums (filling Local Hood or removing material by scoop) Booth 100 cfm sq ft of container cross section 100 fpm at face 3500 3500 Ref. 15, 19. Hood with 1-in. slot extending 120 to 180 deg container. Does not confine spillage. Confine spillage--also recom mended for container up setting Belt conveyors Hood at transfer point Belt speeds less than 200 fpm-350 cfm per foot of belt width, but not less than 150 fpm through open area. Belt speeds over 200 fpm--500 cfm per foot of belt width but not less than 200 ipm through open area 3500 Ref. 18, 20 Bins (closed top) Connect to bin top away 150-200 fpm through open area from feed point at feed points . 3500 Ref. 19, 20 Bucket elevators Tight casing required 10 cfm per sq ft of elevator cas ing cross-section ` 3500 Ref. 19 Brick cutting and sizing Local Hood 500 cfm (abrasive cut-off Booth with saw at face 150 fpm at face wheel used dry) of booth 3500 3500 Ref. 7,19. For portable opera tions. Control not as effec tive as booth Ceramics Dry pan Enclosure 200 fpm through all openings Dry press Local at die 500 cfm Local at die 500 cfm . - At supply bin 500 cfm Aerographing Booth . 100 fpm (face) Fettling, brushing, sag Downdraft or side hood 100-150 cfm per sq ft of plan area ger filling, and unload of dust producing operation 3500 3500 3500 3500 3500 Ref. 19, 21, 22 Automatic feed Manual feed Manual feed Cooling Tunnels (foundry Enclosure molds) Crushers and grinders Enclosure 75-100 cfm per running foot ol enclosure 200 fpm through openings 3500 Ref. 20 Ref. 18, 23 Furnaces Stationary melting pots for nonferrous Tilting or rocking melting for non-ferrous Electric Arc for Steel Enclosure Canopy 100-200 fpm at hood opening 3000-6000 cfm . Hood attached to rool 2500 cfm per ton charged ring 1500-2000 1500-2000 2500-3500 Ref. 11, 15, 22, 24, 25 Use higher ventilation rate for toxic fumes Ventilation rate can be ma terially reduced with more complete enclosures General ventilation of melting room may be substituted but involves greatly in creased ventilation rate Industrial Exhaust Systems 705 Table 3 .... A Guide to Ventilation Rates for Typical Industrial Equipment (Continued) State or Local BegiWafions Should bo Consulted end Followed Where Higher Ventilation Sates ore Specified Operation . Typa of Hood VontSotioa Air Flow Jsued Transport Velocity Fpm RooMric* and Reference* Furnaces Forge (hand) Canopy 200 fpm at face 1500 Ref. 24 Garage (tail pipe at serv Local hood slipped over 100 cfm thru 3-in. flexible duct icing location) tail pipe for autos up to 200 hp 200 cfm thru 4-in. flexible duct for trucks and autos above 200 hp 400 cfm thru flexible duct for Diesel engines 2000 Ref. 15 Granite cutting and fin ishing Pneumatic hand tools Local hood Surfacing machine Local hood 500 cfm 5500-6000 500 cfm for tools up to 2^6-in. 5500-6000 diameter 1000 cfm for 2%- to 2%-in. di ameter ' .. Ref. 26, 27 Typical hood 3 x 8 in. opening with 3-in. flange Hood surrounds tool Grinders Polishers, buffers, etc. Standard wheel hood Portable Downdraft bench ' Swing frame Booth Booth See Table 5 . Bench type, 2-400 cfm per sq ft of exhaust grille but not Iks than 150 cfm per sq ft of plan working area. 100 fpm at face 100-200 fpm indraft through opening in booth face 3500 3500 3000 Ref. 22, 28 Ref. 15, 19, 22, 29 . Recommended for larger parts (Usual cfm per grinder 2000 4000) Kitchen range Canopy 100 fpm at hood face - 1500-1800 Provide drip gutter on all in terior vertical walls to catch condensed grease. Ref. 30 Laboratory hood (pro Booth type vide with door) 50-lOCrfpm Ref. 24, 31. Air supply loca tion very critical Metalising Local hood Booth 200 fpm at hood face 125-200 fpm at booth face 3500 3000 Ref. 15. Not recommended for toxic materials Use higher ventilation rates for toxic materials Mixers Enclosure Motion picture projector Enclosure (caroon arc) Pharmaceuticals Blenders Coating pans Fully enclosed Hood Centrifuges Enclosure Hammer milla Oscillators Shakers Mixers - Local hood Hood Process kettles anc Enclosure tanks 100-200 fpm through feed and 3000-3500 Ref. 19, 22 inspection openings 12-100 cfm (for fume and gas re moval) directly exhausted from projector housing Ref. 31.1000-1500 cfm or 20-30 air changes per hour for heat removal 100 to 200 fpm through opening 2500-3500 120 cfm exh'24-in. dia pan 60 cfm supply direct to pan Differential 60 cfm 3000 250-300 fpm through opening 1500-2000 200 fmp but not less than 50 cfm Exhaust required only when filling or emptying Flexible exhaust hood connec tion extended into pans. Feed opening covered to greatest possible extent Centrifuge to be provided with cover for 50-75 percent of opening Not less than 75 cfm per sq ft o: 2500-3500 Hood with slot at each end of plan area mixer . . 100-250 fpm through opening or 1500-2000 Ref. 33. Use higher ventilation manhole rate when contents are being heated 706 CHAPTER 52 1959 Guide Table 3 .... A Guide to Ventilation Rates for Typical Industrial Equipment (Continued) State or local fagtrfoft'ow* Should be Coraufterf end Followed Where Higher Veatfaftaa Kate* are Specified Operatiso Type of Hood Veatikrtioo Air Row Utucd Transport Velocity Fpm Remark* end Reference* Pouring hoods Foundry Side hood 200 to 300 cfm per lioear ft ol hood with slot velocities ol 1500 fpm. Exhaust take-ofl every 8 to 10 ft 3500 Ref. 20 Rock drilling Dry drilling (rock) Special trap (see refer- 60 cfm--vertical (downward) erenees) work 200 cfm--horizontal work 3500 . Ref. 28,27. May vary with size and speed of drill. Wet drilling offers alternate con trol methods Rubber calender rolls . Canopy--tide panels 75-100 fpm indraft 3500 Ref. 24, 31 Quarts fusing Booth on bench 150-200 fpm at faee Ref. 34, 35 Screens Vibrating Flat deck . Enclosure 150-200 fpm indraft through hood openings but not less th*n 25-50 cfm per sq ft of screen area 3500 Ref. 15, 19 8hakeouts Foundry Enclosure 200 fpm through all openings in enclosure, but not less than 200 cfm per sq ft of grate area 3500 Ref. 20, 22 Spray coating Booth--operator inside 100-200 fpm at booth cross-sec tion Booth--operator out 150-200 fpm at booth cross-sec side tion Booth--downdraft 100-200 fpm downdraft 1500-2000 1500-2000 1500-2000 Ref. 15 Use higher ventilation rate for small booths 4 sq ft or less Tanks, open surface See Table 6 Ref. 36, 37, 38, 39 Tumbling mills Hollow trunnion type Exhaust connection by Use branch diameter same size manufacturer as exhaust outlet. For round mills branch dia should be X dia of mill; for square mills branch dia should be 1 in. plus X side dimension of mill 3500-^5000 Ref. 14 Tumbling mills, drums, Enclosure cages, barrels 400 fpm through openings but ' 3500 not less than 75 cfm per sq ft plan area Where equipment is enclosed and dust tight during rota tion, enclosure may not be needed if feed and discharge operations can be otherwise controlled Welding Local hood with flange Downdraft bench Booth 6 in. from are--150 cfm 6-9 in. from arc--275 cfm , 8-10 in. from arc--425 cfm 10-12 in. from arc--600 cfm 150-250 cfm per sq ft grille area 100 fpm at booth face 2000-4000 2000 200Q Ref. 40 Woodworking See Table 7 Ref- 22, 41 Miscellaneous Complete enclosure Packaging, machines, granulators, enclosed dust producing units Packaging, weighing, Booth - container filling, in spection Downdraft . 100-400 fpm indraft through in spection or working openings, but not less than 25 cfm per sq ft of enclosed plan area 50-150 cfm per sq ft of open faee area * 75-150 cfm per sq ft of dust pro ducing plan area 3000 3000 3500 Ref. 19 Industrial Exhaust Systems 707 For high canopy hoods, Equation 5 may be used: q, =. 7.4 Uw fi,4* (5) where lt -- effective height, feet. . The effective height L may be taken as the actual vertical distance from hood to hot surface plus twice the width of the hot surface. Where it is necessary to have, openings at the top of a hood that is filled with heated air, leakage of the hood contents through these openings may be prevented by ncing sufficient ventilation to obtain a face velocity V as calculated from the following equation: T A/ where . lm -- height of the air column, feet. Af - area of the (sharp-edged) openings, square feet. H, -- sensible heat released to air stream, Btu per minute. C = a coefficient depending on the excess of temperature inside the hood above room temperature with values as follows: Temperature excess 0-200 200-400 400-600 600-800 (F deg) Value of C 20 18 16 14 The American Society of Heating and Air-Conditioninq Engineers has recognised the need for design criteria for determining exhaust ventilation .requirements for hot processes in industry. Research studies on this subject have been in progress since 1952, and the results to date have been published.0 Induced Air Flow Where quantities of individual particles are projected through an air space by gravity or by process forces, volumes of room air in proportion to the momentum of the particles are set in motion with resulting intermixing and flow in the same direction as the particles. Exhausted volumes from hoods or enclosures must be sufficient to include this induced air flow if control is to be effective. Induced air flow should be evaluated from high speed rotating machines including pulverizers, from material handling systems employing high speed belts or involving large tonnages of falling granular material, and from escaping compressed air jets from pneumatic tools. The energy represented by material of various particle sizes and falling heights has been computed by Hemeon.1* The theoretical equivalent induced air flow resulting from un enclosed air streams is summarized in Table 4. Where falling streams occur largely within an enclosure such as a storage bin, it should be recognized that much of the air set in motion is recirculated within the bin. Exhaust volumes from the enclosure need only include the extra air induced before the falling material enters the enclosure although the recirculating induced air can cause localized positive pressures and outward leakage if the enclosure is not of airtight construction. The amount of air induced by falling material is much less if the space through which the material falls is en closed effectively than if not enclosed, and can be re- Table 4 .... Indueed-Air-Row Equivalent of the Energy in Falling, Unenclosed Streams of Partides (Foe a tofld* flow rote R of I lb per mc and a (pacific gravity i c I referred to water) Stroam Faffing DUna,t Area, cq ft Ah Flow Eqeirateflf,-Cfm, to be multiplied by (R/x)*** Partide Size, MtBanelerK 1 2 5 10 20 50 100 3 ft . 6 ft 12 ft 20 ft 30 ft X 450 350 220 180 150 80 65 1 750 550 350 300 250 150 100 2 1200 850 550 450 350 200 170 4 1900 1400 850 700 600 350 250 8 3000 ??no 1400 1100 900 500 400 15 4600 3300 2000 1700 1400 800 650 25 6400 4600 3000 2500 2000 1000 900 50 10000 7500 4700 4000. 3200 1800 1400 X 350 300 250 200 150 1 600 500 350 300 200 2 900 700 600 400 350 4 1500 1200 900 700 500 8 2300 1800 1500 1000 900 15 3500 2800 2200 1500 1300 25 5000 4000 3200 2300 1800 50 8000 6000 5000 3700 3000 X 560 450 350 270 220 1 900 700 600 420 350 2 1500 1100 900 700 550 4 2300 1800 1500 1000 850 8 3600 2900 2300 1700 1300 15 5300 4200 3500 2600 2100 25 7800 6000 5000 3600 2900 50 -- 10000 8000 6000 4700 X 1 800 650 500 370 300 1300 1000 800 600 500 2 2000 1600 1300 960 760 4 3300 2600 2000 1500 1200 8 5000 4100 3200 2400 1900 15 8000 6400 5000 3700 2900 25 -- 9000 7000 5000 4000 X 1000 850 650 500 400 1 1700 1400 1100 800 600 2 2700 2100 1700 1300 1000 4 4400 3500 2700 2000 1600 8 6800 5400 4200 3200 2500 15 10000 8200 6600 4800 4000 25 -- 9000 6800 5400 From Phxniead Proau Ventilation by W, C. L. Hemeon,Tho Industrial Prcm New York (1S5S). duced to-a rnmimirm by enclosing as well as possible the openings at the feed point of the material. DUCT SYSTEM DESIGN The duct system will consist of branch ducts connected to a rnnin duct that will convey the air from the hoods to the exhaust* fan and the air cleaning equipment, if used. Round ducts should be used wherever possible. Their gage size and construction differ from air supply practice due to the rougher usage encountered, and in the pftgp of dusts, to the abrasive effect. (See later section on Construction Specifications for Local Exhaust Sys tems.) Usual conveying velocities are shown in Table 8. Where solid contaminants are handled, recommended ve locities must be maintained throughout the system to prevent material from settling in the ducts and obstructing 708 CHAPTER 52 Table 5 .... Exhaust Requirements* for Grinding, Polishing, Buffing, Scratch Brushing Abrasive Cut-Off Wheels, Grinding and Polishing Belts (Air Volume: 4500 tpm in afi branches.) (2-m. water (action at overage hood.) ' 1959 Guide Wheel Max. Wheel Max (dlo), Width* (die) Cfm (dial. Width* (dia), Cfm ia. In. In. In. In. In. -9 IK 3 225 16-16 2 4 390 -9 2 17-19 3 20-24 4 4H 500 10-16 3 5 610 17-19 4 25-30 5 6 880 20-24 5 31-38 6 7 1200 25-30 6 3H 300 4M 500 5 610 5K 740 6K 1040 Horizontal Single Sfiiodh Disc Grinder* Whoel Branch (dial Cfm In. In. Horizontal Double Spindto Disc Grinder* Wheel Brandi (dial (dia) Cfm K In. Vertical Single Spindle Ditc Grtndart Wheel Branch (dial (dial Cfm In. In. -12 13-19 20-30 31-36 3 4 5 6 225 ' -19 1-5 610 -20 1-4K 500 390 20-25 1-5 880 21-30 .2-4 780 610 28-30 1-7 1200 31-53 2-6 1760 880 31-53 2-6 1760 54-72 2-8 3120 54-72 4-8 6240 Ghxnding ob Poushing Bblts: To 3 in. wide--3 in. branch, add H *n- to branch diame ter for each 2 in. or fraction increase in belt width over 3 in. . * Increase branch (L3 in., bat not less then H in., for each 1 in- in* cicase in width over ditncorion noted. the air flow. For conveying of solid- particles, velocities shown in Table 8 include a reasonable factor of safety and, consequently, design velocities 'may therefore be ad justed as required to permit use of commercial pipe sizes that are available generally in Vs-m. diameter steps through 5-in. diameter, 1-in. steps through 16-in. diameter or larger, and 2-in. diameter steps for large diameters. For contaminants other than solids, conveying velocities are based on a consideration of the higher resistance and lower first cost of smaller diameter ducts against higher first cost and lower resistance of larger diameter ducts. Main ducts connecting two or more branches are sized by the same procedure as for branches. The main should be designed for the total exhaust volume to be handled through all branch ducts. Where exhaust systems handling solids are to provide for a substantial increase of future capacity, required conveying velocities can be maintained by: 1. Providing open end stub branches in the main through which air will be admitted into system until future connection is made. The volume admitted into the main can be adjusted to required air flow rate (cfm) by use of a blast gate or orifice plate in such stub branch. . 2. Arranging the system layout so that exhaust from future points can be picked up by a separate main that will run directly to the fan or air cleaning equipment inlet. CALCULATION OF SYSTEM PRESSURE LOSS The pressure loss of the system includes entrance loss" as air is accelerated through the hood to a branch duct connection, resistance losses of ducts,4* elbows, and junc tions, and acceleration or deceleration losses from ve Tapered hood data from Reference 43. Weatherhood date from Reference 44 Fig. 2 .... Exhaust System Design Datau locity changes within the system. Chapter 21 includes data on duct resistance and on resistance of elbows, and provides sample calculations. In exhaust systems, either the equal friction method (illustrated in Chapter 21) or the use of blast gates in the branches to equalize pressure loss of all runs is employed.*- Data on losses for hood entrance, branch entry, transi tions, and weather hoods are given in fig. 2. The static pressure in branch ducts close to the hood connection is frequently referred to as hood suction. It is the sum of the branch velocity pressure and the hood entrance Io6s. CONSTRUCTION SPECIFICATIONS FOR LOCAL EXHAUST SYSTEMS Correct design and competent installation of sheet steel ducts and hoods, are necessary for the proper functioning of any exhaust system. The foDowing specifications are those recommended in the Industrial Ventilation Manual General . All exhaust systems shall be constructed with the materials recommended herewith and shall be installed in a permanent Industrial Exhaust Systems 709 Process Table 6 ..'. .Ventilation Rates for Open Surface Tanks*-*7 Minimum Vantialioa Rote Miniums Ventilation Rate Cfm Per Sq PI Hood Cfm Per Sq Ft Tank Area Opening lateral Exhaust (Note 1) W/L = Endoring Hood Canopy Hood " 1Wid* RAHO Tank length Minimum Ventilation Rate Minimum Venfitotien Rate Cfm Per 5q Ft Hood Cfm Per Sq Ft Tank Area lateral Fxheutf (Note I) W/l = Enclosing Hood . ' Hood Tank Width Tz--anrk-:L-e--n-grtrh RATIO One Open Two Open Three Open Four Open W/l 0-0.24 Side Side* Side* A8 W/l 0.25 0.49 AB W/l 0.50 1.0 AB One Open Side I $ Io I W/l Three Open Four Open W/l 0-0.24 0.25 0.49 Sides ABA B W/L O.SO- 1.0 AB Plating Acid Mist).. 75 Hydrogen Cy- 65 75 75 Anodizing........... 75 100 125 175 125 175 150 200 175 225 90 100 150 90 130 110 150 130 170 100 125 175 125 175 150 200 175 225 100 125 175 125 175 15(J 200 175 226 100 125 175 125 175 150 200 175 225 65 75 75 Nitric and Hy- Acid............... 75 Metal Cleaning (Degreasing) See Note 2 and Ref. 38 and 39 Metal Cleaning (Caustic or Electrolytic) Not Boiling... Boiling............. Bright Dip (Ni tric Acid). . Stripping Concentrated Nitric Acid. 90 100 150 90 130 110 150 130 170 100 125 176 125 175 1S4J 201 175 225 100 125 175 125 175 150 200 175 225 100 125 175 125 175 150 200 175 225 Stripping Cone. Nitric and Sulfuric Acid... 75 Salt Baths (Molten Salt).. - - SO Salt Solution (Parkerise, Bonderize, Not Boiling... 90 Boiling............. 7b Hot Water (if vent, desired) Not Boiling. Boiling......... 50 75 100 125 75 75 90 100 100 125 75 75 100 125 175 125 175 150 200 175 225 125 60 90 75 100 90 110 150 9C 130 110 150 130 175 125 175 150 200 175 225 125 60 90 id 175 125 175 Note 1--Column A refer* to teak with hood atone one ride or two penile! SKfee rben one hood ia ecemst well or * baffle running length of tank end w high ee is wide; to teaks with exhaust along center line with ~ twnn>in| teak width in W/L Ratio. r-rJi.mn B refer* to freeetendinv tank with hood eloaz one sideor twopereU,el (idee. - Note J--Complete control of the vapors end mist from degreering opentioos requires the ventilation rates as recommended for pickling- However, the Solvents employed in ilf [mnirinf operations ererelatively volatile, end thesolvent lose caused by evaporation increases rapidly as the exhaust rate at the tank irw*TTrTrn Far this reason perfect control is usually sacrificed in favor of tower solvent evaporation rates. Where solvent loss doss not present an important cost or operating problem, the exhaust rates given for pickling should be adhered to, but where advent must be kept at a minimum, an exhaust rate of GO cfm per Sq ft of area is commonly employed. Where this rate is used, ooatrol will be adequate only if the tank islocated in oo area free of drafts and if the degreasing operationsore carried out in accordance with a rigid schedule.* and workmanlike manner. The interior of all ducts shall be smooth and free from obstructions; with joints either welded, flanged, or soldered airtight. Materials 1. Ducts shall be constructed of block iron welded or of galvanized sheet steel riveted and soldered nnlesa the presence of corrosive gases, vapors, and mists or other conditions make use of such material impracticable. Galvanized construction is not recommended for temperatures exceeding 400 F. Welding of black iron of 18 gage and lighter is not recommended for field fabrication. 2. For average exhaust systems on non-corrosive applications the following metal thickness shall be supplied: Diameter of Straight Duct* (Inches) U. S. Standard Gage for Steel Owct Clas* 1 ass 11 ' aan III Dp to 8......... :.............. 24 22 20 ' Over 8 to 18................. 22 20 18 Over 18 to 30................ 20 18 16 Over 30........ . 18 16 14 Class I. Includes non-abrasive applications such as paint spray, woodworking, pharmaceutical and food product, and dis charge ducts from dust collectors. ., Class II. Includes applications for non-abrasive material in high concentration (low-pressure pneumatic conveying); mod erately abrasive material; and highly abrasive materials in light concentrations. Typical applications are conveying of chemiraila and wood dust; exhaust of foundry shakeouts and unnd handling systems, gram dusts; coal crushing and screening; exhaust of grit blast cabinets; arid grinding, buffing, and polish ing. * ' Class III. Includes applications for all highly abrasive ma terials in moderate to heavy concentrations and moderately abrasive materials in heavy concentrations such as low-pressure conveying of tobacco; exhaust systems from sand and gnt blast ing and abrasive cleaning operations, from rock and ore screen ing >d crushing, from dryers and kilns, and fly ash removal from boiler stacks. ;. Where aluminum, duct is indicated, the following equivalent BAS gage thickness of sheets should be used: Steel--U. S. Standard Gage 26 24 22 20 18 16 14 Aluminum--B A S Gage 24 22 20 18 16 14 12 3. For exhaust systems on corrosive applications, considera tion should be given to non-corrosive materials or coatings. (Continued on p. 7It) 710 CHAPTER 52 1959 Guide Industrial Exhaust Systems 711 Table 7 .... Exhaust Requirements for Woodworking Operations41 (Air Velocity: 4000 fpa m a0 brondtei anfea acted ufteiwt) Table 8 .... Approximate Conveying Velocities AIR ROW PRODUCING EQUIPMENT Self Feed Table Rip Saw Jointers Use 1-6 in. branch at bottom pulley; 1-4 in. branch at saw Up to 6 in. knives___ bead. 6 in. to 12 in. knives.. 12 in. to 20 in. knives. Large Self Feed Rip Saws Other Than Table Saws Over 20 in. knives.... Use 1-6 in. branch at bottom; 1-6 in. branch at top. 1-4 in. branch 1-5 in. branch 1-6 in. branch 1-7 in. branch Meferiuf Coowfd Dedga Velocity fpa 2,000 3,000 3.500 The principal types of air moving equipment are cen trifugal fans, axial flow fans, and venturi ejectors. Chapter 22 includes information on fan types, arrangements, and application. Gravity stacks have application for some sys tems handling higher air temperatures or steam where no air cleaning equipment is installed.. Swing Saws . Single Planners or Surfacera ' Up to 20 in. use 1-4 in. branch; over 20 in. use 1-4in. branch. Up to20 in. max. working width..................... 1-6 in. branch 20 in. to 26 in. max. working width............ 1-7 in. branch Circular Saws 26 in. to 32 in. max. working width............. 1-8 in. branch ' 32 in. to 38 in. max. working width............. 1-9 in. branch Up to 12 in. dia.................................................... 1-4 in. branch Over 38 in. max, working width...................... 1-10 in. branch Over 12 in. dia...................................................... 1-5 in. branch Dado head saws.................................................... 1-5 in. branch Gang Circular Saws ' Double Placers or Surfacers .Upper head Ventilation rate depends* on effectiveness of hood and man- , Up to 20 in. max. working , mum number and diameter of saws. width.................................... 1-6 in. branch 20 in. to 28 in. max. working Disc Sanders - Up to 12 in.............................................................. 1-4 in. branch 12 in. to 18 in. dia............................................ 1-4K in. branch 18 in. to 26 in. dia................................................. 1-5 in. branch 26 in. to 32 in.dia................................................. 2--4 in. branch 32 in. to 38 in. dia... .----- 1-4 in. branch and 1-5 in. branch 38 in. to 48 in. dia............. 1-5 in. branch and 2-4 in. branch width.................................... 1-7 in. branch 26 in. to 32 in. max. working width.................................... 1-8 in. branch 32 in. to 38 in. max. working width.................................... 1-9 in. branch Over 38 in. mar. working width.................................... 1-10 in. branch Lower 1-5 in. branch 1-6 in. branch 1-7 in. branch 1-8 in. branch 1-8 in. branch Multiple Drum Sanders (over the table) Molders, Matchers, Sizers (see note) Up to 31 in. wide.................................... 5 in. branch (see note) Matcher head Top Bottom 31 in. to 49 in. wide.............................. 6 in. branch (see note! Up to 4 in.. 2--4 in. branch 1-5 in. branch 1-6 in. branch 49 in. to 67 in. wide.............................. 7 in. branch (see note) 4 to 6 id-- 2-5)4 in- branch 1-6 in. branch 1-6 in. branch Over 67 in. wide. .. ............................ 8 in. branch (see note) 6 to 8 in___ 2-6 in. branch 1-7 in. branch 1-6 in. branch Note: One branch of se indicated required for each drum Fewer branch pipe* 8 to 18 in... 2-6 in. branch 1-8 in. branch 1-8 in. branch may bauaedaa baa *a total branch pipe ew wirtionnl area i* oot reduced. Bone Note: Where profiler is used, provide additional pipe not 1cm thanthat specified for mansfactarcn taa 1 extra branch of equal rise on feed aide. 1--4 in. branch nay be required far crhiinrtint bed rubber cmhione or iwinniMPy operated brush 3,500-4,500 Large particles, heavy loads, moist materials 4.500 and over (Continued from p. 709) 4. Elbows and angles shall be a minimum of two gages heavier than straight lengths of equal diameter. 5. Hoods shall be a minimitm of two gages heavier than straight section of connecting branches. 6. Where flexible piping is neoessary, a noa-collapsible type of flexible piping shall be used and its length shall be kept at a minimum. Construction ' 1. Longitudinal joints of ducts shall be lapped, and riveted or spot-welded on 3-in. centers, maximum Double-lock seams may be used on Class I application only. 2. Girth joints of ducts shall be made with lap in direction of air flow with 1-in. lap for diameters up to 19 in. and lVi-in. lap for diameters over 19 in. 3. Elbows and anglea shall have an inside or throat radius of two pipe diameters whenever passible. Large radii are recom mended for heavy concentrations of highly abrasive dusts. Con struct elbows 6 in. or less in diameter of at least five sections, over 6 in. diameter of seven sections. Prefabricated elbows of smooth construction may be used. Angles'shall be pieced pro portionately. 4. Hoods must be free of sharp edges or burrs and Khali be reinforced to provide neoessary mffnwai System Details Centrifugal fans are most frequently used for the bulk of exhaust system applications due to the system pressures involved. Where air cleaning equipment is included, fans are usually located on the dean air side. The paddle wheel or modified paddle wheel designs are heavily constructed and have few blades to make them more suitable if wear, corrosion, or accumulations are a factor. The higher efficiency backward-curved blade designs find application where relatively clean, non-corrosive air is handled. For ward-curved blade designs have limited application due to the number, shape, and metal thicknegi of the short curved blades. Belt driven fans are recommended by many designers because a change in fan speed is often needed where future changes of the system may be involved, where added pressure losses from air cleaning equipment im provements are anticipated, or where the fan may be used at some later date for another application. The axial-flow fan is used for systems having low-pressure losses. Propeller or disc designs develop pressures under I in., the vane-axial designs develop higher pressures but seldom are used where pressures exceed 3 in. The venturi ejector** is an inefficient method of air movement, but has the advantage of causing air flow without having the exhaust air pass through the air flow producing equipment. It minimizes the explosion or cor rosion potentialities in certain types of system. !j Single Drum and Spindle Type Sanders Wood Shapers 1. Connect duct to fan inlet with split sleeve drawband one ... Fans, motors, and drives should be located so that safe Up to 50 sq in. sanding surface................ 1-3 in. branch 1-4K to 10 in. branch for each spindle according to size and pipe diameter long but not less than 12 in. " ' and easy access for periodic inspection, servicing, and 50 to 200 sq in. sanding surface........................ 1-4 in. branch character of work. 2. Transitions in mains and sub-mains are to be tapered; a maintenance is possible. , 200 to 400 sq in. sanding surface...................... 1-5 in. branch taper 5-in. long for each I-in. *hng in diameter is recommended 400 to 700 sq in. sanding surface...................... 1-6 in. branch when possible. AIR CLEANING EQUIPMENT 700 to 1400 sq in. sanding surface.................... 1-7 in. branch Tenoner 1400 to 2400 sq in. sanding surface................... 1-8 in. branch For cut-off saws: Up to 12 in. dia.................... 1-4 in. branch -Over 12 in. dia...................... 1-5 in. branch 3. All branches shall enter the main at the large end of the transition at an angle not to exceed 45 deg (30 deg is preferred). Connect branches only to top or sides of with no two As discussed in detail in Chapter 24, air cleaning equip ment should be considered in all systems where it can ; Horizontal Belt Sander or Edge Sander (see note) Drive Pulley Idler Pulley Use 1-5 in. branch minimum for each top and bottom tenon, cope, and dado head. Up to 6 in. wide...................... 1-4^ in. branch 1-4 in. branch 6 in. to 9 in. wide.................... 1-5 w. branch 9 in. to 14 in. wide.................. 1-6 in. branch Over 14 in. wide...................... 1-7 in. branch 1-4 in. branch 1-4 in. branch 1-5 in. branch Automatic Lathes Use 1-3 in. to 1-10 in. branch according to work length. branches entering diametrically opposite. 4. Provide dead end caps within 6 in. from last branch of all mains and sub-mains. . 5. Provide access openings or cleanouts every 10 ft and near each elbow, angle, or auct junction in horizontal sections except for non-corrosive gases and vapors containing no particulate prevent property damage, neighborhood pollution, or re entry of polluted air to the working space, or where it can salvage usable material, reduce fire and explosion hasards, or make posable some recirculation of air to the working spaces. The present growing emphasis on air Note: Where men thaa one belt is used, the pipe risea specified shall be requited matter. . pollution control makes it desirable to remove all con for each halt. Where e common hood b uaed for mere thaa one belt, a atacle pipe ct ea am not tea than the eem of the areas of the pipes specified may be < Where belt b rerenible, pipe at idler pulley shell be the ebe specified for the drive pulley. Air volume based on 50 cu ft per lb of refuse conveyed. Use 4500 fpm minimum conveying velocity. Vertical Belt Sanders (rear belt and both pulleys enclosed) Floor Sweeps Up to 6 in. wide................................ 4J in. branch on bottom Use 6 in. branch for fine dust to 8 in. branch for coarse ma 6 in. to 9 in. wide............................ 5 in. branch on bottom terial. . 9 in. to 14 in. wide........................... 6 in. branch on bottom Mouth at floor, 10 X 4 in. to 12 X 6 in. Over 14 in", wide................................ 7 in. branch on bottom Note: Axes of Soar sweep pipe seed aotbeiaduded incwnputinfismb pipearea. Band Saws and Resaws Up to 2 in. wide........... 2 in. to 3 in. wide......... 3 in. to 4 in. wide......... 4 in. to 5 in. wide......... Over 5 in. wide............. Bottom 1-4 in. branch 1-5 in. branch 1-6 in. branch 1-7 in. branch 1-8 in. branch Top Miscellaneous Equipment 1-4 io. branch Pulley pockets and chain mortises-3 in. branch: dovetail and 1-4 in. branch lock corner machines, dowel machines, duplex molding sanders, 1-5 in. branch forming lathes, panel raisers (each bead), ploughs, rail shears, 1-5 in. branch routers, sash stickers (each head) 4 in. branch; pulley stiles-5 in. 1-5 in. branch branch; glue jointer-6 in. branch. 6. Support duets sufficiently to prevent placing of any load on connected equipment and to carry weight of system if plugged with material. Use maximum supporting interval 12 ft lor 8 in. or smaller ducts and 20 ft for larger ducts. . 7. Provide 6 in. minimum clearance between ducts and ceil ing, wall, or floor. 8. Where blast gates are used for adjustment of system, place them near connection of branch to main, provide means of locking after adjustments have been made. Butterfly-type dampers shall not be permitted. 9. Fire dampers, explosion vents, etc- should be installed in accordance with NFPA Codes or local fire ordinances. 10. Rectangular ducts can be used only when clearances prevent the use of round construction. Rectangular ducts must be as nearly square as possible. Weight of metal, lap, and other construction details are to be the equal of round duct con struction whose diameter equals the longest side. 11. Where State or local laws conflict with the specifications given, the more stringent regulation 6hall be followed. Any other deviation must Be approved before installation. taminants to the greatest practical degree based on reason able cost and maintenance. MAKE-UP AIR REQUIREMENTS A correctly designed exhaust system may be ineffective during periods when windows and doors are closed. This condition should be anticipated and prevented by making provision for an adequate air supply. Poor performance of exhaust hoods is caused by: absence of air supply systems; cold drafts due to high indraft velocities through cracks and openings in building construction especially at windows and doors; reverse air flow through lowpressure systems of roof ventilators or general ventilation systems; downflow through heater vent stacks preventing exhaust of flue gases to the outdoors. Systems for condi tioning make-up air do not necessarily increase heating requirements for the space, as cold air due to infiltration 712 CHAPTER 52 1959 Guide Process Table 9 .... Resistance to Corrosion of Materials Used for Hoods and Ducts48 0 j "0 1 t3 | | a1 |3 ,e | | 1 o E| 8 S J 4X z 1 _1 v S l Sa S | g 2-5 3* iz il 1 8 5*8 20 |l I Iot |3 75 S V 8 X *o a IJ |1 ij 3 E 11 *j j? si -ox Sy || i5 |3 if <>> Asphalt PfienoCc Resin Acid, Chromic (Plating and Anodising).............. EP EP s ES SP S S P SF P EF E Acid, Hydrochloric........... Acid, Hydrofluoric........... EP P E S F PS E E4 S E F E E EF S S S F EP F E4 E EF Acid, Nitric........................ Acid, Oxalic (Anodizing). P EE ES E E FP F S F SE E Acid, 8ulfuric.................... Acid Dipping and Pick- P P S5 E6 E E7 P E S EP S F F ES E E5 EP E ling (Boris Ducts)........ Alkaline Cleaner (Caustic P FE E 140-180 F)....................... Alkaline Cleaning Solu- EP EP E SE ES S SE E tions................................. 2 E E E EE E Alkaline Plating (Cu, Cd, Ag)................................... EP EP E S ES 8 S S S E Plating and Anodizing (Horizontal Ducts)....... Plating, Bright Nickel__ Platine and Dinning (Ver- SP SP P SE SE S E SE tical Ducts).................... P F EE Tanning, Dressing, Dye* ing. Bleaching Sol .... S8 S9 E Water, Boiling and Steam. EP SP E E E ES E ES E Decarbonising Ageots___ 3 E E Degreasing Compounds: Organic & Mineral Sol.. E E E Enamels and Lacquers (Coating A DiDDing)... E S Fabric Impregnation........ 3 Salt, Supersaturated So- lution 300-400 F............. 3 S E Wire Insulation............. . S uamocarren Approximate oar*ice ui* E--Excellent............................. Over 5 Teen 8--Satisfactory......................... 2 to 6 yean F--Fair...................................... H to 3 years P--Poor..................................... 6 months Combinations (EF)..................Indefinite rating *Nrotes: 1. Batins* ere .based, upon co.l.la.ted, ,So,l.a serv-ice reports. Indefinite cat.i&s* ere g.iven _wh, ere repor.ts are inconsistent due to varying operating conditions (rash ss dilution, cipcwire to weather, eta.). Blank spaces <tenote insufficient information, not poor service. 2. Mild soaps, detergents, water soluble oils. 14D-180 P. 3. Creosote oil, kerueiDC, ethylene dichloride, t. To 2D percent: E; 60-7U percent, L50F: 8. S. To 60 percent, plating: E; 20 percent anodising, agitated 80 F: 8. 6..To SO percent plating: 8; over SO percent pickling, 20 percent anodizing: E. 7-6-22 percent, 136-216 F pickling: S; plating, pickling, anodising: E. 8. Except add. 9. Add. from the outdoors must be heated somehow to maintain comfortable temperatures in the area. The cost will de pend on the ratio of exhaust air to that required for ven tilation of the space occupied. MAINTENANCE OF PERFORMANCE Periodic inspection and checking of exhaust systems are necessary if control is to be maintained at the effective level of the original installation. Continued effectiveness depends on maintained design air volume flowing through the exhaust hoods. A checking procedure, therefore, must include some data to indicate at least relative air flow' through the hoods. The static pressure or hood suction measurement will prove useful for such checking if data are available on air volumes and pressures at the time the system was installed. Testing and recording of such data for each new installation are of the utmost im portance. While hood suction readings have rightfully been dis carded as a means of measuring air flow, they do offer a quick and accurate method of measuring relative air flow. If the hood suction is known while an exhaust system is functioning properly, its continued effectiveness can be assured so long as the hood suction is not reduced from its original value. Difficulty from plugging may be encountered where Industrial Exhaust Systems 713 Process Table 10 .... Resistance to Corrosion of Materials Used for Exhaust Fans48 a } uJj 1 6 4 1 5 j X o | o J i < T5 11 J % >iX 13 X 3 | 4. 8 z *8 5 | 2| i*8 8|<< Arid Dinning. Pickling, and StriD- EP s Alkaline Cleaning........................... EF s E E E E SP EP E s E ES E E F s ES EEF p E Anodizing......................................... SF s E EE EE E Coating--Enamel and Lacquer... E E E sE Decarbonising................................. ES EP E EF Degreasing and Metal Cleaning.. ES ES E Hardening and Quenching...----- ES ES Plating.............................................. EP S E ES S ES E E E Washing and Rinsing..................... EP E E SP SE E F OOomiMf'ifniwtfeaii Approximate Service life K__FrwlWit.................. Over 6 yws 8--Satisfactory............... J to S yon f--fair.......................... 6 mentM to 2 years p--Poor......................... 6 months * Combination*.................Variable performance '' . Note: Ratlnga axe booed npou collated field service report*. Forward carved teas are not recommended for opeu- tank ventilation eervioe. Cleanout doom and bottom drain* are recommended on all Can* on open tank operation*. The depute which build up on fan wheel* and cnaing* ohould be removed by regular cleaning Repaint where any eoating ho* been broken and removed. . heavy dust loads or moist air are encountered. Unless . the hood design is altered or there are accumulations in the hood or branch pipe between hood and point of hood suction reading, the air volume exhausted from a hood cannot change without a change in hood suction reading. The Pitot tube can be used for routine check purposes instead of the static pressure method but requires care in reading velocity pressures in ah exact position with the tube paralleling the flow of. air. The hood suction method of checking can, however, be more readily delegated to an assistant having no technical training. U-gages have been standard plant equipment long enough to eliminate any feeling of uncertainty in their use. Since pressure readings vary as the square of the ve locity or volume of flow, a slight change in flow is mag nified by a comparison of gage readings. Normally,' a re duction of volume or velocity of 10 to 15 percent will not be sufficient to reduce the effectiveness of the exhaust system. This range is equivalent to a reduction in static pressure readings of 19 to 30 percent. A marked reduction in hood suction can often be traced to one or more of the following items: 1. Reduced performance by the exhaust fan caused by re duced speed due to belt slippage, wear on rotor or casing, or an accumulation of material in the rotor or casing obstructing the air flow. . 2. Incorrect direction of exhauster rotation. 3. Reduced performance caused by defects in the exhaust piping, such as accumulations of material in branch or main ducts due to insufficient conveying velocities, condensation of oil or water vapors on duct walls, adhesive characteristics of material exhausted. 4. Leakage losses caused by loose cleanout doors, broken joints, holes worn in duct (most frequently in elbows), or poor connection to the exhauster inlet. 5. Loses in suction due to exhaust openings added to the system or due to a change of setting of blast gates in branch lines. - 6. Increased pressure loss through the dust collector due to lack of maintenance, improper operation, wear, etc. . MATERIALS REQUIRED FOR CORROSION RESISTANCE Id many cases, exhaust systems including hoods, ducts, air flow producing equipment, and air cleaning equipment will require protective coatings if carbon- steel is used, or other materials of construction will-be required. Need for such materials will be determined by (a) the corrosion rates on interior or exterior duct surfaces,, (6) protection against product contamination, and (c) explosion hazards. Construction for corrosion protection is the most dif ficult due to the complex factors that influence rate of corrosion. It is-seldom possible to predict the concentra tion, composition, and dry-bulb and dew-point tempera tures that will exist in actual operations. A . guide for selecting corrosive resistant materials based on a survey of actual experiences has been reproduced in Tables- 9 and 10.4* REFERENCES The material in this chapter is based largely on the recom mendations of the American Conference of Governmental In dustrial Hygienists as published in the Industrial Ventilation Manual, 1958 Edition. 1 J. J. Bloomfield and J. M. DailaValle: The Determination and Control of Industrial Dust (U. S. Public Health. Service Bulletin 217,1935). *J. M. DailaValle: Exhaust Hoods (Industrial Press, New York, 1952). . 4 T. : Design of exhaust hoods for dust control systems (Journal of Industrial Hygiene and Toxicology, Vol. 18, 1938, p. 595). * W. C. L. Hemecm: Air dilution in industrial ventilation (Heating and Ventilating, February 1941). *B. F. Postman: Practical application of industrial exhaust ventilation for the control of occupation exposures (American Journal of Public Health, Vol. 30, 1940, p. 149). ' W. N. Witheridge: Principles of Industrial Process Ventila tion (University of Michigan, Inservice Training Course, Oc tober 1945). - 714 CHAPTER 52 1959 Guide fP. Drinker and T. Hatch: Industrial Dusts (McGraw-Hill Book Co, New York, 1936). 'J. L. Alden: Design of Industrial Exhaust System* (In dustrial Press, New York, 1948). *W. N. Witberidge: Ventilation (Industrial Hygiene and Toxicology, Vol. 1, Chapter 10, ed. F. A. Patty, Interscience Publishers, New York, 1948). - * A. C. Stem et al: Transport velocities for industrial dusts (American Industrial Hygiene Association Quarterly, December -1948). "A. D. Brandt: Industrial Health Engineering (John Wiley and Sons, New York, 1947). 0L. Silverman: Velocity characteristics of narrow exhaust dots (Journal of Industrial Hygiene and Toxicology, November 1942, p. 267). W. C. L. Hemeon: Plant and /Voces# Ventilation (The In dustrial Press, New York, 1955). 0 Code of Recommended Good Practice for Metal Cleaning Sanitation (American Foundrymen'e Association). * Industrial Ventilation Manual (American Conference of Governmental Industrial Hygienists, 1958, 5th ed.). 0 W. C. Dressen et al: A Study of Asbestosis in the Asbestos Textile Industry (V. S. Public Health Service Bulletin No. 241, 1938). a R. T. Page and J. J. Bloomfield: A Study of Dust Control Methods in on Asbestos Fabricating Plant (if. S. Public Health Reports, Reprint No. 1883, November 1937). ' * Rules Relating to the Control of Silica Dust tn Stone Crushing Operations (New York State Department of Labor, Industrial Code Rule No. 34, July 1942). **J. M. Kane: Design of exhaust systems (Heating and Ventilating, November 1945, p. 68). . ' . . * J. M. Kane: Foundry ventilation (The Foundry, February, March 1946). 0 W. M. Oddie: Pottery dusts: their collection and removal (Pottery Gazette, VoL 53,1928, p. 1280). 0J. M. Kane: Scrapbook of exhaust hood design (Heating and Ventilating, July, August, November 1950 and February, March, April, June 1951). 0 R. T. Pring et al: Design of exhaust ventilation for solid material handling (Industrial and Engineering Chemistry, No vember 1949). ' * Hartsell Blowers: Engineering Data <fc Installation (Hartsell Propeller Fan Company Bulletin 1001). * J. M. Kane: The application of local exhaust ventilation to electric melting furnaces (American Foundrymen's Associa tion Transactions, Vol. 52, 1945, p. 1351). 0 T. Hntrh et al: Control of silicosis hasard in the hard rock industries. II. An investigation of the Kelley dust trap for use with pneumatic rock drills of the jackhammer type (Journal of Industrial Hygiene, February 1932, p. 69). ' "P. S. Hay: Modified design of Hay dust trap (Journal of Industrial Hygiene, January 1930, p. 28). " American Standard for Grinding, Polishing and Buffing Equipment Sanitation (American Standards Association Z 43 1941). J. M. Kane: Swing frame grinder dust control (The Foundry, August 1944). . "J. M. DallaValle: Design of kitchen range hoods (Heating and Ventilating, August 1953, p. 95). " What We Make (B. F. Sturtevant Co. Catalog No. 500). "P. Drinker and J. R. Snell: Ventilation of motion picture booths (Journal of Industrial Hygiene and Toxicology, April 1938, p. 321). "P. J. Marschali: How to justify an industrial air condition ing investment (Heating, Piping and Air Conditioning, February 1952, p. 71). " E. C. Riley et al: How to design exhaust hoods for quartsftiring operations (Healing and Ventilating, April 1940, p. 23). "E. C. Riley and J. M.:DallaValle: A study of quarts-fusing operations with reference to measurement and control of silica fumes (U. S. Public Health Reports, 1939, Vol. 54, p. 532). * A. C. Stem: Ventilation of open tanka (Industrial Hygiene Quarterly, September 1950). . " I. Kingsley: Tabulation of. atmospheric contaminants re leased by open surface tanks (New York State Department of Labor, Division of Industrial Hygiene, Engineering Unit Plate* 161, 162, 163). **K. M. Morse'and L. Goldberg: Chlorinated solvent ex posures at degreasing operations (Industrial Medicine, October 1943, p. 706). m W. N. Witheridge and H. T. Walworth: Ventilation of a trichlorethylene degreaser (Journal of Industrial Hygiene and Toxicology, May 1940, p. 175). 0 American Standard for Safety tn Electric and Gas Welding and' Cutting Operation* (American Standards Association, A 49.1). . - 0 Rule* Relating to the Removal of Dust, Gate*, and Fume* (New York State Department of Labor, Industrial Code Rule No. 12, January 1931).. T. F. Hatch and D. Barron-Oomxco: Air Sow in free con vection over heated bodies (ASHA F. Transactions, Vol. 63, 1957, p. 275). ** A. D. Brandt and R. J. Steffy:' Energy losses at suction hoods (ASHVE Transactions, Vol. 52,1946, p. 205). 0 A. Nutting: Resistance test on pipe (Mechanical Engineer ing, May 1938). - " G. E. McElroy: Design of Injector for Low Pressure Air Flow (U. S. Bureau of Mines Technical Paper 678). - "American Standard Safety Code for Ventilation and Op eration of Open Surface Tanks (American Standards Associa tion, Z 91-1951). CHAPTER 53 INDUSTRIAL DRYING SYSTEMS Drying Terminology, Mechanism of Drying, Internal and External Conditions, Periods of Oryrng, Equilforium Moisture Content, Application of Hygromefry to Drying, Determination of Drying Time, Commercial Drying Time, Dryer Calculations, Drying Methods and Equipment; Rediant, Conduction, and Convection Drying; Agricultural Drying, Solution of Drying Problem ' THE term drying, in a broad sense, encompasses the re and from the dryer. The operating conditions are independent moval of water, and occasionally other liquids, from of time. gases, liquids, word confines the or solids. meaning However, the common usage of principally to the removal of theratCerpiteicraioldmeonisdtsuraencdonthteentfaislltinhga-troabtetapineirniogdwbheegnintsh.e constant- water or solvent from solids by thermal means. Dehumidifica J?ouili6rtttjn moisture content is that to which a givea material can be dried under specific conditions of air temperature and tion is the term that is commonly assigned to the drying of humidity. gases. This is usually accomplished by condensation or ad sorption by various drying agents, and is treated in Chapter Evaporative load is the total amount of water evaporated per hour in the dryer. . .42. Distillation, and more particularly fractional distillation, is associated with the drying of liquids. It is usually more economical to employ, whenever possi ble, mechanical means of separating as much water as is practicable from the solid materials before undertaking dry ing or dehydration steps. These mechanical methods such as Falling-rate period is that drying period during which the instantaneous drying rate continually decreases. Fiber-saturation point is the moisture content of cellular ma terials (wood, etc.) at which the cell wails are completely satu rated while the cavities are liquid-free. It may be defined as the equilibrium moisture content as the humidity of the surround ing atmosphere approaches saturation. filtration, screening, pressing, centrifuging, or settling usually require much less power, and frequently less capital outlay, thereby making the operation cheaper in terms of cost per pound of water removed. Final moisture content is the percentage by weight of moisture remaining in the solid at the end of the drying operation. Free moisture content is that liquid content which is remova ble at a given temperature and humidity. Free moisture may include both bound and unbound moisture. - ' DRYING TERMINOLOGY1 _ The generally accepted definitions of terms used in drying technology follow: . Adiabatic drying occurs in a dryer when all of the sensible heat given up by the air in cooling is used to evaporate water from the wet stock. Batch drying is that type of drying operation in which the material is fed to and discharged from the drying chamber in batches at definite intervals of time. Bone-dry basis indicates the moisture content of a wet solid as pounds of water per pound of bone-dry solid. The advantage of using this basis is that the absolute amount of moisture loss is obtained simply by subtracting the moisture contents before and after drying. (See definition of Wet Basis.) Bound moisture refers to liquid (held by a solid) which exerts a vapor pressure less than that of the pure liquid at the same temperature. Liquid may become hound by retention in small capillaries, by solution in cell or fiber walls, by homogeneous solution throughout the solid, and by chemical or physical adsorption on solid surfaces. Bound moisture ean be removed from a solid only under specific conditions of humidity in the external surroundings. ` Capillary flow refers to the flow of liquid through the inter stices and over the surface of a solid. It is caused by liquid- solid molecular attraction. .. , Fuel economy is the number of units of fuel (cubic feet of gas, pounds of steam, gallons of oil, etc.) required to remove 1 lb of water from the solid being dried. Humidity denotes the amount of water vapor actually pres ent in a gas, and is generally expressed as weight of vapor per unit weight of any gas. Hygroscopic material is material that may contain bound moisture. Initial moisture content is the percentage by weight of mois ture in the solid at the start of the drying operation. Initial moisture distribution refers to the moisture distribu tion throughout a solid when drying begins. Moisture gradient refers to the internal distribution of water in a solid at a given moment in the drying process, the nature of which depends on the characteristics of the solid involved. Non-hygroscopic material is material that can contain no bound moisture. " Test drying rime is the drying time of a relatively cmdl and representative sample of the material which is dried in a labora tory dryer under conditions simulating commercial operation. Through-circulation drying is that method of dryingin which the air flow is directed through a permeable bed of solids. Unbound moisture in a hygroscopic material is that moisture in excess of the equilibrium moisture content corresponding to saturation humidity. All water in a non-hygroscopic material is unbound water. Commercial dry basis expresses the moisture content of a product as pounds of water per p>ound of solid as it leaves the dryer, i.e., per pound of commercially dry solid. Commercial drying time is the residence time of the material being dried in a commercial dryer. Wet basis expresses the moisture in a material as a percentage of the weight of the wet solid. This basis is less satisfactory than the dry-weight basis on which the percentage change of mois ture is constant for all moisture contents. Constant-rate period is that drying period during which the rate of water removal per unit of drying surface is constant. MECHANISM OF DRYING1 Continuous drying is that type of drying operation in which the material to be dried is fed and discharged continuously to When a solid dries, two. fundamental processes are involved: (1) the transfer of heat to evaporate the liquid, and (2) the 715 716 CHAPTER 53 1959 Guide transfer of mms as vapor and internal liquid. These two proc esses occur simultaneously, and the factors governing the rate of each process determine the rate of drying. In any commercial drying problem, a principal objective is to supply the required heat in the most efficient manner. Consequently, heat transfer may occur by convection, con duction, or radiation, or by any combination of these mecha nisms. The various types of industrial dryers may be shown to differ fundamentally with respect to the method used for transferring heat to the solid. In general, heat must flow first to the outer surface of the solid and then into the interior. An important exception is drying with high frequency electrical currents where heat is generated within the solid, producing a higher temperature at the interior than at the surface, and consequently, causing heat to flow from inside the solid to the outer surfaces. Mass transfer in drying occurs as liquid or vapor flow, or both, within the solid, and as vapor flow from the external wet surfaces. The nature of liquid-concentration gradients in solids during drying depends on the mftchflnmm of internal liquid flow, and this mechanism, in turn, depends to a large extent upon the physical and chemical characteristics of the . solid being dried. Internal and External Conditions A study of how a solid dries may be based on the internal mechanism of liquid flow, or on the effect of the external conditions of temperature, humidity, air flow, state of sub division, etc., on the drying rate of the solid. The former pro cedure involves a fundamental study of the liquid flow condi tions within a solid during drying. The latter procedure, although leas fundamental, is more generally used because the effects are easier to establish and the results have greater im mediate application in dryer design and operation. Internal Mechanism of Liquid Flow. Internal liquid flow may occur by several mechanisms, depending on the structure of tim solid. Several mechanisms of flow are as follows: 1. Diffusion in continuous, homogeneous solids. 2. Capillary flow in granular and porous solids. 3. Flow caused by shrinkage and pressure gradients. 4. Flow caused by a vaporization-condensation sequence. 5. Flow caused by gravity. 6. Flow caused by an electrical potential, electro-osmosis. 7. Flow caused by temperature gradients, thermal diffusion. Although more than one of these mechanisms of flow may. be effective at one time, only one predominates as a rule at a given time, in a solid during drying. However, a different mechanism may predominate at a different time in the cycle. The mechanism of moisture flow is usually established experi mentally from a study of moisture gradients. External Variables. The principal external variables in volved in any drying problem are: temperature, humidity, air flow, state of subdivision of the solid, agitation of the solid, method of supporting the solid, and the contact between hot surfaces and wet solid. All these variables do not necessarily occur simultaneously in one problem. Periods of Drying1 A typical drying time curve for a wet solid is shown in Fig. 1. This curve is a plot of the moisture content at any time in a solid undergoing drying. It is the usual method of present ing experimental drying data. Although Ftg. 1 shows that the moisture content is subject to a continuous variation with time, a more precise illustration of the nature of this varia- Fig. 1 .... Moisture Content w vs. Drying Time 9 tion can be obtained by differentiating the curire and plotting the drying rate in pounds of water per (hour) (pound of dry material) against the moisture content in pounds of water per pound of dry material as shown in Fig. 2. The rate curve shows- that the drying process is not a smooth, continuous one in which a single mechanism controls throughout. Section BA on each curve represents a constant-rate period. In Fig. 1, it is shown by a straight line of constant slope dw/d$, which becomes a horizontal line on the rate curve in Fig. 2. The curved portion of Fig. 1 is termed the falling-rate period, and, as shown in Fig. 2, it is typified by a continuously nhftnging rate. Point A, where the constant rate ends and the drying rate begins to decrease, is termed the critical moisture content. The portion of the curve designated by CB in Figs. 1 and 2 represents a warming-up period, and it may, or may not, be a significant item depending on the total time involved. . Constant-Rate Period. Drying during the constant-rate pe riod is equivalent to evaporation from a free-water surface on the surface of the solid. The rate of drying in this period is determined by the rate of diffusion of water vapor through an air film at the wet surface of the solid. A constant rate of evap oration on the surface of the solid maintains the surface at a irir DRYING Rate CURVE B // SI < / 1 `/I 7 MCMSTlttE CONTENT (DRV OASIS) . Froo Keftmtc* 2 Fig. 2 .... Rote of Drying -- vs. Moisture Content w ad Industrial Drying Systems 717 constant temperature, which, in the absence of other heat effects, is very nearly the wet-bulb temperature of the air. If heat flows to the surface of evaporation by radiation and conduction, or both, in addition to convection, the surface temperature will be constant at some value between the air temperature and the wet-bulb temperature. This higher temperature in turn produces a higher constant rate of evaporation. In those dryers in which heat is transferred to a wet solid by conduction through hot surfaces, and heat.transfer by convection is not a factor, the wet surfaces approach the boiling point temperature rather than & wet-bulb tempera ture. When all the heat for evaporation in the constant-rate period is supplied by a hot gas, a dynamic equilibrium is established between the rate of heat transfer to the material and the rate of vapor removal from the surface. This equilib rium between heat and mass transfer rates can be expressed as follows: where dto h,AAt dB " H ktA&p (1) -- " drying rate, pounds of water per (hour) (pound of. - bone-dry material). h, -- total heat transfer coefficient, Btu per (hour) (square foot) (Fahrenheit degree). A * area of heat transfer and evaporation, square feet per pound of bone-dry material. H = enthalpy of evaporation at <, Btu per pound. k, -- mass transfer coefficient, pounds per (hour) (square foot) (atmosphere). 01 = (t. -- l,) -- temperature difference between air and surface of evaporation, Fahrenheit degrees. L, TM air temperature, Fahrenheit. ' t, -- temperature'of surface of evaporation, Fahrenheit. Ap * (p -- p.) = vapor-pressure difference, atmospheres. p. = vapor pressure of water at t,, atmospheres. p = partial pressure of water vapor in air, atmospheres- When ht = he, the coefficient of heat transfer by convection only, then t, under equilibrium conditions becomes , the wet-bulb temperature of the air, and p, is the vapor pressure at this temperature. If heat is also"supplied by radiation, then ht is the sum (Ac + K) where h, is the radiation coefficient , and he is the convection coefficient, and t, becomes higher than the wet-bulb temperature. A similar result occurs when heat reaches the surface of evaporation by convection and con duction. Effect of Air Velocity. The principal effect of air velocity is on he and k, , since the rate of transfer'of heat and mass in the constant-rate period depends mainly on the rate of diffusion of heat and vapor through the air film at the surface of the solid, and air velocity is the chief factor affecting the thickness of this film. The influence of direction of air flow on the heat transfer coefficient he and on the. corresponding drying rate dw. , jg a shown in Table 1. Effect of Temperature or Humidity. Temperature or humidity enters the drying rate equation as a driving force across the air film. The wet-bulb depression, which is the difference be tween the dry-bulb temperature and the wet-bulb tempera ture, is directly proportional to the drying rate in this period. Table \ .... Convection Heat Transfer (hj and Rates of Drying I -- ) Coefficients for Constant-Rate Period Direction of Air Row h. dw d6 , 0.0128G-M , Parallel to plane surfaces* 001286* * Perpendicular to plane sur faces1 0.37G" U.-U Through circulation* (for 0.376*"c. Reynolds number > 300) 0.37c^G9-Atm pJ3D9%-n Letter Symbol* for Table 1 foot pievfoasfy defined) h, " convection heat transfer coefficient, Btu per (hour) (square foot) (Fahrenheit degree). G * mass velocity of dry air, pounds per (hour) (square ' foot). t* = wet-bulb temperature of drying air, Fahrenheit, o - drying area, square feet per cubic foot of bed volume. , = bulk density of dry granular bed, pounds per cubic foot. D, = average diameter of particle, feet. Atm " logarithmic mean difference between air temperature entering and leaving the bed and the wet-bulb tem perature, Fahrenheit. , = humid heat, Btu per (pound of dry air) (Fahrenheit degree). When dealing with heat transfer coefficients the wet-bulb depression is the driving force, whereas with transfer coefficients the driving force is.expressed in terms of humidity or vapor-pressure differential ' Fig. 3 permits a ready estimate of the constant drying rate for various air temperatures mid humidities. The chart is based on the difference between the dry-bulb and wet-bulb temperatures of the entering stream of air, and on an air velocity of 300 fpm. It may be assumed satisfactory for tray drying of any material in the constant-rate drying period. It does not apply to rotary or through-circulation drying. A curve for correcting the air velocity is incorporated in Fig. 3. This curve is based on the variation of drying rate with the 03 power of the velocity. Evaporation from Liquid Drops. For the important problem of spray drying, evaporation rates of liquid drops must be estimated. Below a value of Reynolds number (DpG/p) of 10 for spherical particles, the heat transfer coefficient across the gas film surrounding the drop is given by h -- film'heat transfer coefficient, Btu per (hour) (square foot) (Fahrenheit degree). kf =* thermal conductivity of gas film, Btu per (hour) (square foot) (Fahrenheit degree per foot). 718 CHAPTER 53 1959 Guide Equation 2 is applicable when the Reynolds number for liquid drops is less than 10. Drop diameters are almost al ways less than 500 microns, and are usually in the range of 20 to 150 microns. The rate of evaporation of drops may be expressed in terms of heat transfer or transfer. In terms of heat transfer, the evaporation rate is given by the equation: dxo 2*k,Pp da H (3) where ---- ** evaporation rate, pounds per hour. tary dryers, vacuum rotary and vacuum tray dryers, and in fra-red dryers. A principal difference between indirect drying and direct drying is that, with the former, tire material is usually at a higher temperature then the surrounding air, so that heat is actually transferred to the air instead of from the air. The Falling-Rate Period. In the discussion of the periods of drying, it was shown that the drying process is discontinuous, consisting of a period of a constant rate of evaporation and a period in which the rate continuously decreases. (See Fig. 2.) This latter period is usually designated as the falling-rate period. It begins when the constant-rate period ends at the critical moisture content. If the critical moisture content is Icgy than tire required final moisture content, the constant- rate period will constitute the whole of the drying process. On the other hand, if the initial moisture content is less than the critical moisture content, as in the case of some slow- drying matwwala, such as soap and wood, then no constant rate will appear, and the whole of the drying process will be in the falling-rate period. This period, in the most general case, can be divided into two tones which may be termed (1) the rone of unsaturated surface drying, and (2) the zone where internal liquid flow controls. The rone of unsaturated surface drying follows immediately after the critical point and results from a progressively de creasing wetted surface. With the surface no longer completely wetted, dry portions of the solid protrude into the air film, so that tire rate of evaporation per unit of total surface is reduced. The effective wetted surface in this zone is frequently a linear function of the water content, so that the curve repre senting rate of drying vs. water oontent of the solid is straight in this region, as shown by line AD in Fig. 2. The mechanism of drying is essentially the name as during the constant-rate period. The zone where internal liquid flow is in control is usually the second zone of the falling-rate period. In this phase the rate of internal liquid movement by one or more of the con trolling mechanisms considered previously, such as diffusion, capillarity, etc., will determine the drying rate. When diffusion does control in the falling-rate period, it obeyB the fundamental laws of diffusion as those ap plying to the diffusion of heat. Thus for the case where the surface is dry or at the equilibrium moisture oontent, and the solid has a uniform initial moisture distribution, the following rate equation holds for relatively large values of time 6, and when (to -- to)/(to, -- toj < 0.6 Drying at Air Temperatures above the Boiling Point of the Liquid. When the temperature of the drying air is maintained above the boiling point of the liquid being evaporated, or when superheated vapors are used for drying, the usual equations for maai transfer, expressing rate of evaporation as a function of the vapor-pressure difference, lose significance, since large errors are introduced in the expression for vapor-pressure driving force due to its apparently-small value. Such cases can be treated conveniently on a basis of heat transfer, since a temperature difference must alwayB exist in order that drying may proceed. Constant-Rate Period When Heat Transfer Depends on Conduction and Radiation. In indirect drying, where heat transfer and drying do not depend on the flow of heated gases, the drying rate depends either on heat conduction through retaining walls to wet material in contact with such surfaces, or on radiation, or both. This applies to drum dryers, agitated pan dryers, indirect continuous sheet dryers, steam tube ro- dv> : ( - u>.) dS (4) w = moisture content on dry -basis, at any time 9, pounds of water per pound. ' to, -- moisture content at equilibrium with external condi tions, pounds of water per pound of dry material, to, -- initial moisture content at start of diffusions! period,. pounds of water per pound dry material. d the liquid diffusivity, square feet per hour. L ~ one-half material thickness, feet. Equation 4 is restricted to a slab-shaped solid, the length of which is large compared with the thickness. For some materials the drying time in the falling-rate period varies directly with the thickness. When this occurs the falling Industrial Drying Systems 719 Table 2 .... Approximate Classification of Materials Most Likely to Obey Equations 4 and 5 Material Obeying Equation 4 1. Single-phase solid systems such as soap, gelatin, glue. 2. Wood and similar solids below the fiber saturation point. 3. Last stages of drying starches, textiles, paper, clay, hydro philic solids, and other materials when bound water is being removed. -' Materials Obeying Equation 5 1. Coarse granular solids, such as sand, paint pigments, min erals, etc. 2. Materials in which moisture flow occurs at concentrations above the equilibrium moisture,content at atmospheric saturation, or above the fiber saturation point. rate can be expressed with fair accuracy by the following equation: ), idw/dS)t , (ttfe -- toj W to,) (5) (dw/d0). the constant drying rate, pounds per (hour) (pound dry material). falling rate, pounds of water per (hour) (pound of dry material). the critical moisture content, pounds per pound dry material. (aThe appropriate expression for obtained from Table 1, may then be substituted in Equation 5. Table 2 gives an approximate classification of materials that are most likely to obey Equations 4 and 5. Equilibrium Moisture Content In the drying of solids it is important to distinguish between hygroscopic and non-hygrosoopi<f materials. A hygroscopic material is one which retains a definite percentage of moisture PER CENT RELATIVE HUMIDITY fig. 4 .... Typical Equilibrium Moisture Content Corves1 under definite conditions of air humidity. This bound moisture is in a state of equilibrium with tire water vapor in the sur rounding air. A decrease in the water vapor oontent will decrease the amount of equilibrium bound water. Water so retained by a solid in equilibrium with the humidity of the surrounding air, is designated as the equilibrium moisture content. Such moisture may be held as adsorbed surface films or condensed in fine capillary structures at reduced vapor pressure. The equilibrium moisture content varies with the tempera ture and humidity of the surrounding air. Consequently, any correlation of equilibrium moisture content should these two factors into account. However, at low temperatures, e.g., 60 to 120 F, a plot of equilibrium moisture content cs. percent relative'humidity, expressed as 100 (p/p,), is .essen tially independent of temperature. Such a plot usually re sults in a curve of double curvature with a point of inflexion (see Fig. 4). .' APPLICATION OF HYGROMETRY TO DRYING In analysing any particular drying problem it is sometimes advisable to consider the thermodynamic changea involving the drying medium, since in most cases the drying medium is an air-water-vapor mixture. The thermodynamic prooess can be traced on a psychrometric chart. The psychrometric chart. Fig. 5, suggested by Grosvenor,* is suitable for most drying calculations. The adiabatic cooling lines on the chart indicate the paths along which the changes in the thermodynamic properties of the air occur in an adia batic dryer. . The theoretical ability of air to pick up moisture corre sponds to tiie difference between the final saturation content at the wet-bulb temperature (approximately the adiabatic cooling temperature or thermodynamic wet-bulb temperature) and the initial moisture content at the supply air dew point. The maximum posable pickup is never achieved in practical dryers because on the haris of good design, this would be undesirable. Experience has shown that there is an optimum pickup which is a function of the independent drying variables and is less than the marimmn theoretical value as obtained from the psychrometric chart. It should be noted that in practice the process will not necessarily follow exactly the adiabatic cooling line since there may be a transfer of heat to the tray or conveyor itself. Use of the psychrometric chart for analyzing drying prob lems is illustrated by Example /. Example 1: Assume a dryer having a capacity of 100 lb of gelatin per hour at 11.1 percent bone-dry basis. The initial mois ture content is 228 percent bone-dry basis and the final mois ture content is to be 32 percent bone-dry basis. The rate of pro duction of bone-dry gelatin is 90.5 lb per hr. Supply air is available at 120 F dry-bulb, 85 F wet-bulb, with make-up air at 80 F dry-bulb and 65 F wet-bulb. Air ia exhausted from the dryer at 100 F dry-bulb and 84.5 F wet-bulb. Find (1) the required amount of make-up and exhaust air, and (2) the percentage of recirculated air. Solution: Refer to psychrometric chart. Fig. 5, and obtain the humidity ratio of the make-up air and of the exhaust air. In order to maintain a steady-state condition in the dryer the water which is evaporated from the material must be carried away by the exhaust air. Therefore, the difference between the humidity ratio of the exhaust air and that of the make-up air (known as pickup) is equal to the water evaporated from the material divided by the pounds per hour of dry air in the ex haust. Step t: The moisture in exhaust air at 100 F dry-bulb and 84.5 F wet-bulb is found to be 0.022 lb per pound of dry air. The moisture in make-up air at 80 F dry-bulb and 65 F wet- 720 CHAPTER 53 1959 Guide bulb is found to be 0-010 lb per pound of dry air. Therefore the moisture pickup is 0.022-0.010, or 0.012 lb per pound of dryair. ' ` The amount of water evaporated in the dryer " 90.5 (2.28 -- 0.32) = 177 lb per hr. The weight of dry air, make-up and exhaust, required to remove the water of evaporation =* M.750 lb of dry air per hour. Step t: Let x = percentage of recirculated air and 100 -- x = percentage of make-up air. Then (humidity ratio of exhaust and recirculated air) + a (humidity ratio of make-up air) humidity ratio of supply air. Hence, ^ (0.022) + X- (0.010) 0.018 at 120 F dry-bulb, 85 F wet-bulb, ori " 66.7 percent recirculated air and therefore the required make-up air TM 33.3 percent. DETERMINATION OF DRYING TIME In most drying problems it is necessary to obtain the dry ing tirna of a particular material. Three methods are listed below in.order of preference. 1. Conduct tests in a laboratory dryer simulating conditions in the commercial machine, or obtain performance data directly from the commercial machine. ' 2. If the specific material is not available, obtain drying data on similar material by either of the above methods. This is subject to the experience and judgment of the investigator. 3. Estimate drying time from the theoretical equations which have been considered under Mechanism of Drying. In designing commercial equipment the usual procedure is to conduct tests in a laboratory dryer in which commercial Operating conditions are simulated. A representative sample in the physical form of the material as used in the laboratory testa should be identical to that which will be encountered in commercial operation. Otherwise the test results may not be an accurate indication of the drying characteristics of the commercial material. In many cases where it is impracticable to run laboratory testa, commercial drying data are derived from the experience of the equipment manufacturer. This should not be overlooked since it can be an important source of data which would other wise have to be obtained by less reliable methods. Method 3, estimating drying time from the theoretical equa tions, should be used only as a last resort because it yields only approximate values. Commercial Drying Time The first step in selecting a commercial dryer is to apply the estimated drying time to determine the sice of the commercial machine necessary for a given capacity. If the drying time has been derived from laboratory teste it is necessary to con sider the following factors: 1. In a laboratory dryer considerable drying may have been effected by radiation and conduction of heat to the material, whereas in a commercial dryer these factors are usually negligi ble. 2. Humidity conditions in a commercial dryer may be higher than in a laboratory dryer. For drying operations with con trolled humidity, this factor can be eliminated by duplicating the commercial humidity condition in the laboratory dryer. 3. Operating conditions usually cannot be kept as uniform in a commercial dryer as in a laboratory dryer. ' 4. Because of the relatively "mail sample used, the test ma terial may not be representative of the material handled com mercially. In consideration of the preceding factors 1 to 4, it should Industrial Drying Systems 721 be stressed that the test drying time must be corrected to suit commercial conditions. This is a matter of experience and judgment on the part of the designer. DRYER CALCULATIONS To determine preliminary cost estimates for a commercial dryer it is usually necessary to make the following calcula tions: - Circulating air. The amount of circulating or supply air required is established by the optimum air velocity with refer ence to tiie material. This may be obtained from laboratory tests orprevious experience, keeping in mind that there is also an optimum moisture pickup for the air, as explained in the section Application of Hygrometry to Drying. Make-up and Exhaust. The amount of make-up and exhaust air required to maintain steady-state conditions within the dryer is discussed under the section Application of Hygrome try to Drying. In any continuously operating dryer, the rela tion between moisture content of the material and quantity of make-up air is given by Equation 6 -- Wi) -- M(wi -- tDj) where Wt is constant. (6) where > Gt -- dry air supplied as make-up air to the dryer, pounds per hour. M *= stock dried in a continuous dryer, pounds per hour. Wi *=> humidity ratio of entering air, pounds of water vapor per pound of dry air. Wi " humidity ratio of leaving air, pounds of water vapor per pound of dry air. toi -- moisture content of entering material dry basis, pounds of water per pound. ut -- moisture content of leaving material dry basis, pounds of water per pound. In batch type dryers, the drying operation is given by Equa tion 7 ` 4.- Heating of the vapor from the wet-bulb temperature in the dryer to the exhaust temperature. . 5. Heating of the total water in the material from the enter ing temperature to the wet-bulb temperature in the dryer. 6. Heating of the make-up air from its initial temperature to the exhaust temperature. The energy absorbed by items 1 to 6 must be supplied by the fuel. The proper selection and design of the heating equip ment is an important part of the overall design of the dryerl DRYING METHODS AND EQUIPMENT Drying systems are sometimes classified according to the method of heat transfer that is employed, since the entire - problem of drying resolves itself into individual problems of heat transfer and the thermodynamics of air and water vapor. The methods of heat transfer are radiation, conduction, and convection. Many types of dryers have been built on these principles for different purposes. ' Drying systems can also be classified, according to the method of product handling, as batch operation, semi-con tinuous, and continuous. The method of supporting or transporting the material to be dried, efficiency of operation, cost of investment, and. the method of applying heat to the material are to be considered in selecting the equipment. Usually the final selection is a compromise between mechanical design, heat efficiency, quality, and product loss. - A systematic procedure is often justified when selecting a dryer for a given process. A general procedure will consist of: , 1. Survey of suitable dryers 2. Preliminary cost estimates of various types a. Initial investment b. Operating cost 3. Drying tests should be conducted in prototype or labora tory umts of the most promising equipment available. Some times a pilot plant is justified. 4. Summary of tests to evaluate quality and samples of the dried products. - GOT. - H\) - M,~ - dS (7) Some items may overshadow the operating cost, or the in vestment cost, such as: where . Mi weight of material charged in a discontinuous dryer, pounds per'batch. dw -- = the instantaneous rate of"evaporation corresponding to to. W\ is a variable during a portion of the cycle. 1. Product quality, which should not be sacrificed. 2. Dusting, solvent, or other product losses. 3. Space limitation. 4. Bulk density of product which may affect packaging cost. A comprehensive bibliography for special reading will be found in the article by S. J. Friedman.* In actual practice the quantity of make-up air supplied is kept constant and is based on the average evaporation rate. Equation 7 then becomes identical with Equation 6 where M -- -k. Under this - condition the humidity in the batch dryer will vary from a maximum to a minimum during the drying cycle; whereas, in the continuous dryer the humidity at any given point is constant with constant load. Heat Balance. In order to estimate the fuel requirements of a dryer it is usually necessary to make a beat balance, con sisting of the following: 1. Radiation and convection losses from dryer. 2. Heating of the commercial dry material to the leaving temperature (usually estimated). . 3. Vaporisation of the water being removed from the ma terial (usually considered to take place at the wet-bulb tem perature). - Radiant Drying In artificial systems, radiating surfaces heated by steam, . electricity, or other means, afford a good method of heat distribution and control. Radiant beating sets up convection currents, and consequently, in low temperature dryers, only about one-third to one-half of the total heat for evaporation is actually supplied to the material by radiation. At high tem peratures the radiation output increases rapidly, according to the fourth-power law. The total radiation may be computed by the equations and tables given in Chapter S. In general; fins and irregular surfaces do not increase radiation, hence, the area to be used in calculations is the area of a smooth-surface envelope enclosing the radiating elements. A certain amount of air circulation is required through a radiant dryer in order to carry off the vapor. Radiant heat from infra-red lamps has been accepted by 722 CHAPTER 53 1959 .Guide certain industries as practicable for their specific problems. An example of successful application is found in the drying of lacquers. ' Conduction Drying Drying rolls or drums. Fig. 6,7 flat surfaces, open kettles, and immersion heaters are examples of the direct-contact method. Intimate contact of the material with the hauling surface is important, and in some cases agitation is desirable to increase the uniformity of heating or to prevent over heating. A rather interesting method of conduction drying was put into practical use during the war for the drying of blood plasma, and has since been expanded to other fields such as the preservation of bacteria and other micro-organisms. This has come to be known as freeze drying or drying by sublima tion. The material to be dried is first frozen and then placed in a high vacuum chamber connected to extremely low tem perature condensers. The water b removed by vaporising from the solid directly to the gas without ever becoming liquid. Convection Drying (Direct Dryers) A typical convection dryer is composed of an air-condition ing system, a material handling system, and the dryer hous ing. In normal practice it is desirable to recirculate as much as 95 percent of the air, from the standpoint of heat economy. There is an optimum point for the percentage of recirculation, depending on the temperature and evaporation rate. A limited amount of convection drying takes place in almost any dryer such as those described in the preceding paragraphs. However, to be classified as a convection dryer the principal source of heat is the heated air or other gases circulated in the dryer. There are a number of nw.hn.nir?d means of accomplishing this circulation of air or gases, each of which has some particular virtue. Brief descriptions of some important types of convection dryers follow: Rotary Dryers. These dryers are cylindrical drums which cascade the material bong dried through the air stream. (See Fig. 7.) The dryers may be heated directly or indirectly, and the air circulation may be parallel or counterflow. A variation b the rotating-louver type dryer, which introduces the air beneath the flights thus securing very intimate contact. Cabinet and Compartment Dryers. These are generally con sidered batch dryers wherein each charge b dried to comple tion before removal.7 A wide range includes types from the heated loft with only natural convection, and usually poor and non-uniform drying, to the self-contained units with forced draft and properly designed baffles-which give positive re sults. It b also possible to evacuate some of the systems for low temperature drying of delicate or hygroscopic materials. These dryers are usually loaded with material spread in trays to increase the exposed surface. The trayB are loaded directly into tire dryer or may be stacked on trucks which are wheeled in. (See Fig. 8.) Tunnel Dryers. Tunnel dryers are a modification of the compartment dryer, and as a rule are continuous or semicontinuous in operation. Heated air or combustion gas - b usually circulated by means of fans, although a few natural draft units are still in use. The material b hundlpd on trays or racks on trucks, and moves through the dryer either inter mittently or continuously. The air flow may be parallel, counterflow, or a combination of the two, obtained by center exhaust. Further, the air flow may be across the surface of the trays or up or down through the bed, or in any combina tion of directions. By reheating the air in this type of dryer or recirculating it, a high degree of saturation b achieved before exhausting the air. This reduces the waste of sensible heat. A variation of this type dryer b the strictly continuous type having one or more mesh belts which travel through the dryer carrying the product, such as Tig. 9. Innumerable combina tions of temperature, humidity, air direction, and velocity are possible. The labor requirement b low on such a dryer, as it can be loaded and unloaded mechanically. There b the dis advantage of hot air leaks at the entrance and exit, although these can be minimized by means of baffles or inclined ends where the material enters and leaves from the bottom. Spray Dryers. In recent years the spray dryer has become important for the drying of liquids in many fields, especially in the food industry. SECTION THROUGH OftYCA HEAR FEED END HOT AIR INLET fig. 7 .... Cross Section and Longitudinal Section Through Grculotion Dryer7 Industrial Drying Systems 723 The liquid b atomized by means of pressure nozzles, air jets, or centrifugal bowls into the air stream of a tower or chamber. Inlet air temperatures may run from 250-300 F up as high as 1200 F. Drying times are very short because of the minute particle size. Particles as small as 5 to 10 microns are formed in spray dryers. The dry powder b separated from the air by cyclone separators which are sometimes followed by cloth bags or scrubbing towers. - Because of the high inlet temperatures and the relatively large volume of air required, the efficiency of the spray dryer b relatively low and, consequently, it b seldom used for dilute solutions (less than 30 percent solid), fig. 10 shows a typical arrangement for a spray drying system.7 . A common and important feature of all spray processing b the direct conversion of the spray liquid to a granular product fig. 8____ Compartment Dryer, Showing Trucks, with Air Gradation7 suitable for packaging without grinding or other intermediate handling. Another aspect b the unusually high rate of drying attained. In a well designed system 15 to 30 seconds b a fair time for the passage of the sprayed particle through the dry ing zone; the particle temperature need not rise materially above the wet-bulb temperature of the drying air. Thb the process particularly adaptable to the drying of heat-sensi- tive material, some of its most important applications being the drying of milk, eggs, potato flour, soap, and blood* Tobacco Curing* Considerable progress has been, made recently in develop^ mg improved tobacco curing systems, through the application of heating equipment for maintaining uniform temperatures. Controlled heat and air circulation shortens the curing period and improves the quality of tobacco. ' Suitable bam ventilation effected by bottom and ridge venting reduces the time and cost of curing. Orientation of bam with respect to the prevailing wind b helpful. Tobacco Re-drying In modem plants, tobacco b re-dried in continuous, con veyor type machines under controlled temperature and humidity conditions. One type of machine re-dries leaf to bacco in hands. Thb machine consists of a drying section, cooling section, and ordering section. As the hands are car ried through the drying section on sticks, a high velocity of air b directed down through the heads, and a low velocity of fig. 9 .... Section of Continuous Dryer, Blow-Through Type air passes over the body of the tobacco resulting in fast and uniform re-drying. - In the cooling section, the tobacco b quickly cooled *nd conveyed through the ordering section, where a controlled amount of moisture b added in this section which b main tained at almost saturated humidity ratio, so that the leaves can be packed for storage without the danger of breakage. Agricultural Drying Information on drying of agricultural products, such as milk, apples, flowers, tung nut, lumber, fruit juices, broom corn, grain, hay, peanuts, tobacco, and other farm crops, may be found in current issues of the Agricultural Index.1* SOLUTION OF TYPICAL DRYING PROBLEM Since there are so many types of dryers that may be used, and so many special conditions surrounding each particular problem, it b usually recommended that those having experi ence with the dryer to be used be consulted. The following example, however, will serve as a guide for typical dryer calculations. Example t: Magnesium hydroxide is to be dried from 82 percent moisture on bone-dry basis to 4 percent moisture con tent on bone-dry basis. The production rate is to be 3000 lb per hr ob 4 percent bone-dry basis. Previous experience indi cates that a continuous single-conveyor through-circulation dryer with a fin-drum feed as illustrated in Fig. 9 should be used. The dryer is to be heated with steam at 50 prig. The op timum circulating air temperature is 160 F which is not limited by the existing steam pressure. Step 1: Laboratory tests or previous experience indicate that the material enters the dryer at a temperature of 60 F, with an initial moisture content of 82 percent bone-dry basis. The test drying time is 25 min and the final moisture content is 4 percent bone-dry basis. The temperature of make-up air is 70 F dry-bulb and 60 F wet-bulb. The temperature of circulat ing air is 160 F dry-bulb and 100 F wet-bulb. The air velocity down through the preformed bed is 250 fpm, and the static pressure drop through the bed is 0.4 in. of water.- The dryer 724 CHAPTER 53 1959 Guide bed is to be loaded with 6.820 lb per sq ft of bone-dry material. Depth of the bed is to be 4 in. . Step t: Previous experience indicates that the commercial drying time is 70 percent greater than the test time obtained in the particular laboratory setup used. ( Therefore, the commercial drying time = 1.7 X 25 = 42.5 min. ' Step 8: In order to dry the desired 3000 lb per hr of material 42 5 - the holding capacity of the dryer is 3000 X -g^- -- 2125 lb at 4 percent bone-dry basis. . The required conveyor area is g2~1^2Q5 " 312 sq ft. Assuming that a perforated plate conveyor with an 8 foot effective width 312 is used, the length of the drying sone is -g- " 39 ft. 3000 Step 4: The amount of water entering the dryer is j-Q^ X jjjjj " 2370 lb per hr, while the amount of water leaving the dryer is X -- 115 lb per hr. Thus, the evaporation rate, in the dryer is 2370 -- 115 ~ 2255 lb per hr. ' Step 6: Since the air circulation is perpendicular to the per forated plate conveyor, 4he total quantity of air that must be circulated equals tne air velocity (based on the face area) multiplied by the conveyor area. Thus, ' Supply air = 250 X 312 -- 78,000 efm From Fig. 5 the humidity ratio of the supply air at 160 F dry-bulb, 100 F wet-bulb is 0.0285 lb per lb dry air. The specific volume of the supply air is 16.33 cu ft of moist air per lb of dry air, from Table 2 and Equation 27 of Chapter 3. The quantity of dry air circulated is 78*,000 X--60 = 286,5^00 l,bL per hr. Step 8: The amount of moisture pickup is = 0.0079 lb per lb of dry air. The humidity ratio of the exhaust air is 0.0079 + 0.0285 - 0.0364 lb per lb dry air. Substitute in Equation 6 and solve for G, the mass velocity of dry air, to determine the required quantity of make-up air. The humidity ratio of the make-up air is 0.0086 lb per lb dry air, from Fig. 5. . G (0.03M-0.0086) - (^)(^l) - G = 81,000 lb dry air per hr. Therefore, 81000 ' Make-up air - ^ ^ -- 28.2 percent. Recirculated air - 71.8 percent. Step 7: Heat Balance . Sensible heat of material " M(tm -- t*i)cm rar (10 - * 03 - 34,600 Btu per hr Sensible heat of water Mv>i(tm -- - 2370 (100 - 60) 1.0 . = 94 300 Btu per hr Latent heat of evaporation -- Af(u?i -- tot)H = 2255 X 1037 ' = 2,338,400 Btu per hr Sensible heat of vapor = 4f(t/>i -- to*) (h -- t*)e, - 2255 (160 - 100) 0.45 = 60,900 Btu per hr Required heat for material ~ 2328,700 Btu per hr The temperature drop (U -- tt) through the bed is Required heat 2,528,700 j__ Supply air, lb per hr X c.286,500 X 034 " 8 Therefore, the exhaust air temperature is 160 -- 37 = 123 P Required heat for make-up air =* Gr(t* -- *i}c - 81,000 (123 - 70) 0.24 \ - 1,030,300 Btu per hr. The total heat required for material and make-up air is 2,528,700 + 1,030,300 = 3359,000 Btu per hr. Additional heat must be provided for the radiation and con vection losses, which may be calculated from the known con struction of the dryer surfaces. LETTER SYMBOLS USED IN CHAPTER 53 A ** area of beat transfer and evaporation, square feet per pound of material. a ** drying area, square feet per cubic foot of bed volume, c, = specific heat of air, Btu per (pound) (Fahrenheit de gree). e* = specific heat of material, Btu per (pound) (Fahrenheit degree). c, = humid heat, Btu per. (pound of dry air) (Fahrenheit ' degree). - ' e, = specific heat of water vapor, Btu per (pound) (Fahren heit degree). c -- specific heat of water, Btu per (pound) (Fahrenheit de gree). d = diffusivity of the liquid or vapor, square feet per hour. D,, = average diameter of particle, feet. . G = mass velocity of dry air, pounds per (hour) (square foot). Gt -- dry air supplied as make-up air to the dryer, pounds per hour. H * enthalpy of evaporation of water at wet-bulb tempera ture, Btu per pound. h -- film heat transfer coefficient, Btu per (hour) (square foot) (Fahrenheit degree). he " coefficient of heat transfer by convection, Btu per (hour) (square foot) (Fahrenheit degree). hr -- coefficient of heat transfer by radiation, Btu per (hour) (square foot) (Fahrenheit degree). ' h, = total gas film beat transfer coefficient, Btu per (hour) (square foot) (Fahrenheit degree). .. . It/ gas film thermal conductivity, Btu per (hour) (square foot) (Fahrenheit degree per foot). Jbf n mass transfer coefficient, pounds per (hour) - (square foot) (atmosphere). L <= one-half material thickness, feet. M -- weight of stock dried in a continuous dryer, pounds per hour. ' Mi * weight of stock charged in a discontinuous dryer, pounds per bateh. Ap -- p, -- p. -- vapor-pressure difference, atmospheres, p. = partial pressure of water vapor in air, atmospheres, p. = vapor pressure of water at t,, atmospheres. U *= air or gas temperature, Fahrenheit. ft -- temperature of particle, solid, or surface of evaporation, Fahrenheit. ' f* = wet-bulb temperature of drying air, Fahrenheit. <1 *= make-up air temperature, Fahrenheit. = temperature of air entering stock, Fahrenheit. t, =* exhaust air temperature, Fahrenheit. Cmi TM entering stock temperature, Fahrenheit. ' tm* = leaving stock temperature, Fahrenheit. At =(* -- t.) = temperature difference between air and sur face of evaporation, Fahrenheit. . Mm = logarithmic mean between temperature entering and industrial Drying Systems leaving the bed, and the wet-bulb temperature, Fahren heit. " humidity ratio of entering air, pounds of water vapor per pound of dry air. Wt " humidity ratio of leaving air, pounds of water vapor per pound of dry air. to TM moisture content on dry basis at any time 8, pounds of water per pound. toc = critical moisture content, pounds water per pound dry material. to* ~ water content, dry basis, of the drop as it enters the drying chamber, pounds per pound of dry solid. to4 -- moisture content at equilibrium with external condi tions, pounds per pound dry material. to, TM initial moisture or moisture content at start of diffu sions! period, pounds per pound dry material. ^ = drying rate, pounds of water per (hour) (pound dry material). / ^ = constant drying rate, pounds per (hour) (pound dry \d8 dry material). (dlD ^ -- falling rate, pounds water per (hour) (pound of \-dd dry stock). 8 TM time, hours. ' p, = bulk density of dry granular bed, density of dry particle, pounds per cubic foot. REFERENCES W. R. Marshall, Jr. and S. J. Friedman: Drying (Perry's Chemical Engineer*' Handbook, McGrawTHill Co., New York, 1950, 3rd ed.). Indicated material supplied by. W. R. Marshall, Jr. and S. J. Friedman, authors of the Section on Drying in tho Third Edition of the Chemical Engineers' Handbook. Permis sion to use this material has been kindly granted to The Guide by the Editor, John H. Perry, and by McGraw-Hill Book Company, publishers of the Chemical Engineers' Hand book. ' ' 1W. R. Marshall, Jr: The drying of foods (Heating, Piping and Air Conditioning, September to December 1942, also No vember and December 1943). * C. B. Shepherd, C. Hadlock, and R. C. Brewer: Drying materials in trays (Industrial and Engineering Chemistry, April 1938). - ^ 4 B. W. Gamson, G. Thodos, and O. A. Hougen: Heat, mass and momentum transfer in the flow of gases through granular solids (American Institute of Chemical Engineers Transactions, 1943). . 1 W. M. Grosvenor: Calculations for dryer design (American Institute of Chemical Engineers Transactions, Vol. 1, 1908, p. 184). . * S. J. Friedman: Steps in the selection of drying equipment (Heating and Ventilating, February 1951, p. 95). T What the air conditioning engineer should know about drying (Heating and Ventilating, December 1942). *B. B. Fogler and R. V. Kleinschmidt: Spray drying (In dustrial and Engineering Chemistry, December 1938). * Tobacco Curing (Virginia Agricultural Experiment Station Technical Bulletin 116, Januray 1951). " Agricultural Index (H. B. Wilson Co., New York). BIBLIOGRAPHY W. H. Carrier: The temperature of evaporation (ASHVE ' Transactions, Vol. 24, 1918, p. 25). 725 J. A. Goff and S. Gratch: Thermodynamic properties of moist air (ASHVE Transactions, Vol. 51, 1945, p. 125). C. F. Pruttoo and C. O. Miller: Factors influencing the per formance of rotary dryers (American Institute of Chemical Engineers Transactions, February, August 1942). W. R. Marshall and 0. A. Hougen: Drying of solids by through circulation (American Institute of Chemical Engineers Transactions, 1942). A. Wcisselberg: Factors that influence dryer performance (Chemical and Metallurgical Engineering, August 1932). 0. A. Hougen: Typical dryer calculations (Chemical and Metallurgical Engineering, January, March 1940). W. K. Lewis, W. H. Carrier, A. E. Stacey, Jr., R. S. Fleming, R. G. Met*, G. B. Ridley, C. O. Lavett, and D. J. Van Marie: Symposium on drying (industrial and Engineering Chemistry, May 1921, p. 427). S. J. Friedman and W. R. Marshall, Jr.: Studies in rotary drying, I and II (Chemical Engineering Progress, 1949). * Symposium on drying (Industrial and Engineering Chemistry, 1938). H. D. Tiemann: Principles of Drying Lumber and Humidity Diagram (Forest Service Bulletin 104,1912). T. K. Sherwood: The Drying of Solids (Massachusetts Insti tute of Technology Bulletin Nos. 237,247, 258). T. P. Brown: Radiant energy drying with heat lamps (Metal Industry, December 1939, p. 607). E. W. Flosdorf: Drying by sublimation (Pood Industry, January 1945, p. 607). ' F. H. Slade: Evaporative drying system (Pood Manufactur ing, March 1943, p. 70). ' 1. R. Berkness: High frequency methods in gluing and drying wood (Wood Products, Vol. 45, 1940, p. 12). T. K. Sherwood: Development of the unit operations of chemical engineering: drying (Chemical and Metallurgical Engineering, vol. 42, p. 214); D. W. Biocheno: The spray dryer--its possibilities in indus try (Pood Manufacturing, June 1944, p. 195). L. E. Stout, K. J. Captan, and W. G. Baird: Mechanism and rate of drying by near-infra-red radiation (American Institute of Chemical Engineers Transactions, Vol. 41, 1945, p. 283). W. B. Van Arsdel: Some engineering problems of the new vegetable dehydration industry (ASHVE Transactions, Vol. 49, 1943, p. 49). V W. Sherman: Electronic dehydration of foods (Electronics, Vol. 17, 1944, p. 94). . Air Conditioning and Engineering (American Blower. Co., 1935). Drying in Industrial Plants (J. O. Ross Company). Badger and McCabe: Elements of Chemical Engineering (McGraw-Hill Co.,-New York, 1931). - Pan Engineering (Buffalo Forge Co.). M. Hirsch: Die Trockentechnik (Julius Springer, Berlin, 1932). Drying (Kent's Mechanical Engineers Handbook). W. H. Carrier: Drying (Mark's Mechanical Engineers Hand book). A Koehler and R. Thelen: Kiln Drying of Lumber (McGrawHill Co., New York, 1926). H. D. Tiemann: Kiln Drying of Lumber (J. B. Lippincott, New York, 1920). O. A. Hougen, H. J.'McCauley, and W. R. Marshall: limita tions of diffusion equations in drying (American Institute of Chemical Engineers Transactions, Vol. 1, 1940, p. 183). V. P. Victor: An introduction to convection drying and dry ing calculations (Heating and Ventilating, December 1944, p. 67). 726 CHAPTER 53 1959 Guide R. R. Bennett and 8. N. Hawks: Tobacco Curing {University ' Irvin Lavine and O. D. Sutherland: Revised psychrometrie of North Carolina Extension Circular 332, January 1919). chart assists high temperature design {Chemical and Metal . L. 8. O'Baanon: Principles of Burley Tobacco Bam Opera lurgical Engineering, April 1928, p. 228). |i tion (University of Kentucky Bulletin 501, May 1947) . E. M. Matthews. M. H. McVlckar, and R. B. Davis, Jr.: C. R. Wilkie and O. A. Hougen: Mass transfer in the flow of gases through granular solids extended to low modified Rey Fuels for Curing Tobacco (Virginia Agricultural Experiment nolds numbers (American institute of Chemical Engineers Station Bulletin No. 396, May 1946). ' Transactions, Vol. 41, 945, p. 445). N. C. Teter and E. G. Moss: Beating Tobacco Bams with W. R. Marshall: Current Status of the Theory and Practice of i Stokers {North Carolina Agricultural Experiment Station Bul letin No. 352, May 1945). Drying (University of Wisconsin, Engineering Experiment Station Reprint No. 265). ' I CHAPTER 54 OWNING AND OPERATING COSTS Fixed Charges: Amortization, Interest,Taxes, Insurance, Rent; Maintenance Costs; Labor for Operation; Energy and Water Costs: Operating Refrigerating Equipment, Condenser Water, Heating HE total cost for the use of heating, ventilating, and 2. Heat distributing equipment including direct radiation, Tair-conditioning systems may be divided into two classi piping, etc. ing fications. The first of expense of ownership, these is the relatively fixed and unvary and the second is the variable and 3. Air handling equipment conditioners, filters, controls, including etc. fans, air heaters, air somewhat controllable expenditure for actual operation of 4. Air distribution system including ducts, outlets, grilles, etc. the equipment. Owners and prospective purchasers of this ' 5. Refrigerating equipment including piping, pumps, etc. equipment are particularly concerned with both since the actual expenditure is generally predicated upon the possible return on the investment resulting from increased patronage, . 6. Water conservation devices including towers, evaporative condensers, etc. 7. Insulation of pipes, ducts, and equipment. greater efficiency on the part of the employees, meeting of 8. Building alterations, furring-in ducts and pipes, structural work, etc. competition, or the improvement and maintenance of quality in a manufactured product. These costs may be grouped under four headings: (1) Fixed Charges, (2) Maintenance Costs, (3) Labor for Operation, and (4) Energy and Water Costs. "" To estimate the first cost of any system prior to installa tion, the best procedure is to determine the heating and cool ing load, and then after thorough engineering study, select the type of system. The installed cost of systems will vary RXED CHARGES widely, depending upon the type of equipment selected, and the design of the distribution system, equipment and labor Fixed charges are the annual expenses anting from tbe^ costs in the locality, demands for the particular installation, ownership of the installation, including use of the owner's etc. A reasonably approximate cost may be determined for a money, and protection of the equipment in the form of in selected design in a given locality from the sum of the es surance. Such costs are usually unchanged from year to year timated unit costs of the component parts of the system. regardless of whether the equipment is in or out of service. A reasonably precise estimate of the cost of the components Fixed charges may be grouped- under five headings: (1) may be obtained from cost records of recent installations of Amortization, (2) Interest, (3) Taxes, (4) Insurance, and a, comparable design, or from quotations submitted by (5) Rent. .. manufacturers and contractors. Amortization Approximate costs are given in Table 1 for mechanical air-handling systems including heating and cooling coils for As air-conditioning equipment becomes older, its ability or capacity to perform present and future service is reduced. Provision must be made for the owner to recover each year a portion of the initial value of the equipment as an expense to be charged against revenue, or to amortize the cost. This decrease in the value of property is usually determined by an accountant or engineer using some theoretical method and will depend upon (1) the total first cost, and (2) the amortization period. . The total first cost of an installation is the actual capital expenditure required to buy and install the air-conditioning, heating, or ventilating system ready for operation. It repre sents the first cost of the equipment combined with addi tional costs incurred because of the installation of the system. The first cost of air-conditioning, heating, or ventilating systems includes the following: . distributing lVk cfm per square foot of floor area and re frigeration equipment based upon a requirement of one ton for every 333 sq ft of floor area. Different types of service demand may change the floor area per ton of refrigeration and air volume per square foot between wide limits and, con sequently, the table should be used with caution. Other first costs may be incurred because of the installa tion of the air-conditioning or heating and ventilating sys tem. These will include such items as electrical work, plumb ing, miscellaneous piping, building alterations, cutting, patching, furring-in of ducts or pipes, foundations, structural supports, remodeling or redecorating after installation, con sulting engineer's fees, licenses, and permits. As these costs vary widely no approximations are practicable. Therefore, each case must be considered individually. If a quotation can be secured from a manufacturer or contractor covering the complete job, it will usually include the items that have been mentioned. '- I. Heat producing equipment including boilers, burners, The length of the amortization period to be used depends controls, etc. - upon (1) the type and remaining life of the building or 727 728 CHAPTER 54 1959 Guide Table ?.... Cost Dollars per Ton for a Complete System, Including Heating and Cooling Coils, Fan, Ducts, Refrigeration Equipment, Temperature Controls, etc* 12 3 5 Unit Cost* 6 78 Total Corf* 9 10 11 Unit Cotfib 12 13 Refriger ation Root Ana Sqft Air Distrib uted Ca Ft Refrigera tion Equip ment per Ton Ovcts, Fan*. Heat ing Cclb, etc. Refrigera tion Equip ment dl'mg Equipment Total Fvaporafive Per Tan Per Sq Ft Floor Per Cfm Condenser! Per Ton* Per ton* 25 8,333 12,500 250 50 16,666 25,000 224 75 25,000 37,500 212 100 33,332 50,000 204 150 50,000 75,000 195 200 66,664 100,000 192 250 83,333 125,000 187 300 100,000 150,000 182 400 133,328 200,000 165 500 166,666 250,000 158 1.05 0.98 0.95 0.92 0.91 0.90 0.88 0.86 0.84 0.82 6,250 11,200 15,900 20,400 29,200 38,200 46,800 54,600 66,000 79,000 13,100 24,500 35,700 46,000 68,200 90,000 110,000 129,000 168,000 205,000 19,350 35,700 51,600 66,400 97,400 128,200 156,800 183,600 234,000 284,000 775.00 730.00 690.00 664.00 650.00 641.00 628.00 612:00 585.00 568.00 2.32 2.15 2.07 1.99 1.95 1.93 1.88 1.84 1.76 1.71 1.55 1.43 1.38 1.33 1.30 1.28 1.25 1.23 1.17 1.14 190.00 155.00 120.00 90.00 60.00 52.00 50-00 48.00 46.00 44.00. 42.00 40.00 *Tbeee eat dram (baaed oa 18S4 prices which mar be adjusted by asiog current building ccot inrier) cover only the aveiece type of comfort *j_______ . _ open ipeca ee in department (torts. or far industrial air eonditioninc Involving large arena. Where a multiplicity of email spaces must be individually controlled, as iu OSes bmMinch totals, and apartment bwset, these oosta do not apply. Indudm only final wattt, drain, and electrical connections within the equipment room. b Cotamos 9, 10, and 11 mprment cot* where well water or city water is available Icn condensing purposes. Whoe conservation of water is required, add column IS cr 13 to column 3 to obtain total coat per tan. ...... .' Does imt indude coetof structuralreinforcing if required, to support tbs weight of coming towers or evaporative eosdensen. . space for which the system is to be used; (2) the type of equipment to be employed as a part of the system; (3) the character of the business; and (4) the lease or ownership conditions. . Depreciation, due to deterioration or obsolescence, must be considered in arriving at the amortization period. Main tenance *nH deterioration usually have the effect of offset ting one or the other. If a long depredation period is to be used, then the item for maintenance, repair, and the re placement of wearing parts must be greater than for a short depreciation period. . In determining the length of the amortization period, the owner's accounting practices will have considerable bearing upon the number of years used in the calculation. For taxation purposes, this period depends upon the use and the service to which the equipment is applied. At the present time indications are that varying interpretations on depre dation wifi be made by the Bureau of Internal Revenue. While most air-conditioning equipment may be considered as having a normal useful life of 20 years for depreciation purposes, no final value for depreciation should be deter mined without consultation-with the owner's tax consultant or perhaps referral to Schedule F which is issued by the Bureau of Internal Revenue and summarized in Table 2. Interest . The interest charged to the cost of ownership may be based upon the. average interest rate for the period during which the first cost of the equipment wifi be amortized. While some accountants do not include interest in the an nual fixed charges and consider it a negligible item, the money invested in air-conditioning, heating, or ventilating equipment, must be either borrowed or diverted from the owner's funds and converted to the purpose of making the installation. Whether it is borrowed or taken from surplus funds, the money that might have been earned as interest is properly chargeable to the operation of the system. Toble 2 .... Probable Useful life of. Equipment* Ufa m Years 1. Heat Producing Equipment (a) Boilers................................................... (ft) Stokers and burners........ ................. 20 20 2. Heat Distributing Equipment (0) Piping--copper.................................... (6) Piping--iron......................................... (c) Radiation--concealed........... ............ (d) Radiation--direct............................... (e) Valves and specialties:...'................ as bldg. 20 25 25 10 3. Aib Handling Equipment (el Filters--automatic............................. (ft) Heating and cooling coils................. (c) Spray humidifiers and dehumidifiers. (d) Fans....................-.................................. (e) Air-conditioning units....................... {/) Motors................................................... (a) Electrical starting equipment:....... (ft) Pneumatic control systems............... (1) Electric control systems.................... 20 20 10 15 10 20 20 15 ' 15 4. Aib Distributing Equipment io) Ductwork........................... .. ft) Outlets, grilles...................... c) Duct insulation.................... 5. Repbigebattng Equipment (a) Centrifugal refrigerating machines., (ft) Reciprocating refrigerating ma chines.................................................... (e) Motors and starters.......................... (d) Piping--copper................................... () Piping--steel....................................... (f) Pumps................................................... le as bldg. 15 20 ` 20 20 20 20 20 20 6. Water Saving Devices () Evaporative condensers.................... () Cooling towers........................-........... (c) Wells...................................................... 15 15 25 * Taken from U. 8. Bureau of Internal Revenue 8ektjith tj ProbabU Umfal Lift, revised 1042. . Owning and Operating Costs Table 3 .;.. Owning and Operating Cost Firtf Coif Cost of mechanical system. Other costs............................ First Cost (FC)--Total. Annual Fixed Charge* Amortization--Depreciation period Y years............................................................. Interest rate i%..........................;................ Amortization and Depreciation FC -y- -- .... Interest: ^y ^ X i X cost ......... Taxes.....................................'.......................... Insurance. ....................................................... Rent............................... :................................ Annual Fixed Charges: . (Total).................................................. Replacement or servicing of air filters... Outside maintenance service..................... Water treatment........................................... . Lubricating oil and grease......................... Painting for corrosion protection or other purposes....................................................... Replacement of worn parts......................... Refrigerant...................................................... Wages of engineer or operator........... ....... Anoual Maintenance Cost- Total....... '................................................ Annual Service Cart Electric power costs Fans..................................... Pumps--chilled water__ Pumps--condenser water. Pumps--well water.......... Cooling tower fans....... .. . Cooling tower pumps....... Refrigeration machines... Miscellaneous or other... Gas............................................... .. Coal.............................................. ,-r. Oil--for boilers or Diesel engiues. Steam - For Direct heating.................... For Ventilatioo--preheaters.. For Ventilation--reheaters..... For Turbine driven equipment. For Engine driven equipment.. Sewers Charges for discharging water into pub- Annual Service Costs: .. ' Summary it- j r<w Annual Sa Ann 1 | " p | Annual Owning and Operating Costs-- Total............................................................. 729- Table 4 .... Approximate Combined Operating and Maintenance Cost for Large Air-Conditioning Installations, Using High-Quality Equipment* Dodart par(Fan) (Food Repairs for refrigeration machinery.......... Refrigerant...................................................... Oil and grease................................................ Painting (Water boxes and debumidifiers) . Filters, clean and re-oil 4 times per ye&r. Controls, outside service............................ Cleaning air conditioners........................... Total............................................................... * F<ti*vi*t--1 for 1959. 1.07 0.40 . 0.11 0.45 1.50 0.26 1.38 The formulas for computing interest and amortization are given in Table 3. This table also serves as a check list for the various items to be considered in calculating the cost, of ownership and operation. .' Taxes , The taxes that may be charged to the property as a result of the improvement due to the installation of an air-condi tioning system, will vary according to the practice of the official agencies levying property taxes. Insurance . Insurance against losses by fire is ordinarily secured by mergasing the building fire insurance coverage to cover all -or part of the first cost of installing the air-conditioning and other mechanical systems. Various types of extended coverage are available for protection against a number of other types of losses. Boiler insurance may be extended to cover the air-con ditioning equipment to protect against losses due to explo sion, rupture of piping, and similar hazards. Since insurance rates vary widely depending upon the type of structure in which the equipment is located and the nature of the own er's business, the rates are usually set by rating organiza tions specializing in this work. Exact figures on insurance cannot be determined without consultation with the owner's underwriter. - Rent If the equipment under consideration is to be located in rented or leased quarters, or if additional space must be rented, such expense becomes a fixed charge. MAINTENANCE COSTS Maintenance charges consist of expense for labor and material necessary to make repairs and replace parts, as well as cleaning, painting, inspection, etc., for the purpose of Ruminating or minimizing the need for repairs. Generally, routine maintenance labor requirements will be the function of an operating engineer or staff. If the responsibility, of this group may extend to other facilities beyond the equip ment being discussed, here, it is important that only an equitable share of the group's time be charged to main tenance. - . Extraordinary repairs are quite often handled by separate maintenance divirions and the expense charged back- to air conditioning, heating, and ventilating. In other cases, all maintenance is handled by. outride service firms and the 730 CHAPTER 54 1959 Guide Table 5 .... Equivalent Full Load Operating Hours of Refrigeration Equipment Used for Summer Cooling May 15 to Oct. 15,` Application Hr Open for Boone** Alionta Chicago Detroit las New New PfcJo- OJcfcdioOrleans York deiphia <no City St. Wadimgton, O. C Barber Shops.......................... 1280 1010 650 720 720 680 1080 830 860 1020 890 940 Department Stores................. 040 840 560 610 610 580 890 700 720 840 750 780 Drug Stores...............'.............. 2100 1630 950 1060 1060 980 1790 1280 1330 1650 1420 1530 Funeral Parlors...................... 600 440. 300 330 330 310 470 370 380 440 400 410 Offices........................................ 940 870 560 620 620 580 900 710 740 880 770 810 Restaurant (Short Hour)___ Restaurant (Long Hour).... Speciality Shops (5 & 10) -- Theaters--Continuous........... Theaters--Neighborhood.... 1290 2100 1090 1500 900 970 1510 800 1010 640 535 820 530 700 420 620 930 590 750 450 620 570 1060 760 800 980 830 930 850 1690 1170 1210 1530 1300 590 560 860 670 690 810 720 750 720 1080 850 870 1020 910 450 430 650 500 520 650 550 * Modm Air Condilimtint, ffsatin# and VmtHalinf, bjr W. H. Carrier, R. E. Cberoe, and W. A- Grant (Pitman Publishing Carp-, W*>. D- 75). 880 1400 750 950 580 cost considered as maintenance. These costs vary con-, siderably- with factors such as the type of system and the proficiency of the installing and servicing organization. Therefore, any forecast of maintenance costs should include consideration of the equipment as a part of the engineering study. The charges should be based upon the entire period under study rather than the early years of operation when, repairs may be expected to be at a minimum. Various estimates of maintenance costs vary from 5 to 10 percent of the installation cost. Table 4 is based upon an average-of 7Vi percent for about a 75-ton installation. This probably would apply to most installations using high- quality equipment. The maintenance cost must be modified for size of job and quality of equipment. With lower-cost equipment, higher maintenance costs can be expected. The accounting practices of the owner and the rules of the Bureau of Internal Revenue affect the charges for major overhauling or complete replacement which may restore, the capital value of certain equipment items. In these cases the expenditure may not necessarily be charged as maintenance but will become a fixed charge spread over the remaining years of equipment life. Table 4 gives some approximate costs for maintaining large air-conditioning installations using high-quality equipment. - LABOR FOR OPERATION In some cases wth the installation, of automatic equip ment, operating labor may be non-existent, but where such labor is required, the cost is readily calculated. Where opera tors are required, the expense is often considered main tenance, but tinea they may have other functions'that are not properly charged to operation of the air-conditioning, heating, or ventilating installations, the charges should be properly allocated. This cost of experienced and competent operators is well justified in medium and larger plants by economies that can be achieved in maintenance and energy costs. -- ENERGY AND WATER COSTS Energy costs include the costs for power, water, steam, coal, oil, etc., consumed to operate the system. From the selected equipment and type of installation, it is possible to segregate the relatively constant power loads and the total brake horsepower. Annual power cost can then be figured from the following formula: annua,l power cos.t ---0--.7--4--6-(--b-h--p)-H---R-v ' ,,(vl; - where bhp = brake horsepower. H ** annual operating hours. R power rate, dollars per kwhr, 9 " motor efficiency (decimal). . In using Equation 1 it must be pointed out that the electric rate, R, must reflect the proper combination of energy and demand rates. These vary widely between the utility companies, and sometimes the rate structure is such that it is largely the demand charge which determines the proper value of R to use in Equation 1. Operating Refrigerating Equipment Id an air-conditioning system the refrigerating equipment is usually the largest power consuming item to be considered. Also, the prediction of operating cost is more difficult be , cause the power required for summer cooling is affected by many factors of a variable nature. . ' Table 5 gives the equivalent full-load operating hours of refrigerating equipment used for summer cooling for the period of May 15th to October 15th. This table was cal culated from the following equation: ' . H, - m(6 + ef) : (2) where . H. = equivalent full load operating hours of refrigeration equipment used for summer cooling during period May 15 to October 15. m -- total hours during period May 15 to October 15 that the establishment is open for business. b " fraction of maximum load from internal heat under average operating conditions, c = fraction of maximum load that is due to external sources at maximum design conditions. ' / - ratio of the number of hours for a particular city, when the outdoor wet-bulb exceeds 65 F, during the period Juoe 1 to October 1 to the total number of hours Owning and Operating Costs 731, during that period. Total hours are assumed as 8 . The average gallons per minute per ton must take into, hr per day period for barber shops, department stores, account the variable water temperature. When well water funeral parlors, offices, short-hour restaurants, and is used as a source, and entering and leaving temperatures specialty shops, and 12 hr per day period for drug are considered constant, the average gallons per minute per; stores, long-hour restaurants, and theaters. ton obviously are equal to the design gallons per minute per ton. However, when the source is river or lake water, its It should be pointed out that certain southern cities may maximum seasonal temperature will generally be reached have seasons longer than the 5-month period indicated in at the same time that the refrigeration load factor is highest. Table 5. If it is desired to consider a longer season of opera The average gallons per minute per ton should be calculated tion, the ratio of full-load operating hours to hours open for ' ' from known or estimated water temperatures, because they burines is smaller; in other words, the refrigeration load vary through the season. Maximum water main tempera factor is lower. This is true because the extra increment of tures are given in Chapter 41, but should always be verified days added will be a relatively light load, since the table locally. In lieu of this tedious work, the average gallons already includes the more severe part of the season. per (minute) (ton) may be taken as 80 percent of design The season electrical power cost for refrigerating equip gallons per (minute) (ton) with reasonable accuracy, for ment is then given by the following equation: ' the-condition of variable temperature of entering water season power cos.ts -0--.-7-4- 6---(bh--p-)-,-7--W---.-R 0) obtained from rivers and lakes. Cooling towers and evaporative condensers virtually where - eliminate condensing water charges since the windage and evaporation losses are seldom over two or three percent of (bhp) i = brake horsepower per ton (see Fig. 1) for average load during period. (Due allowance should be made for poorer compressor efficiency at light load.) T = maximum refrigeration design load, tons. R, -- equivalent full load refrigeration operating time, hours (from Table 5). - R " power cost, including demand and energy charges, dollars per kwhr. ' 9 = motor efficiency at average load (decimal). In considering refrigeration power consumption, it should be noted that the use of weather records for a specific year the water circulated. The savings in water consumed often will not in itself justify the installation of water-economizing equipment omm the cost for pumping and the fixed or ownership charges may be in excess of the annual cost for once-through con densing operation. If operating costs are to' be the basis for selection, then fixed charges should be determined when studying application of this equipment which usually has a shorter life than the other components. Usually the primary factors influencing the installation of water conservation equipment are the lack of an adequate water supply or local regulations intended to conserve an existing water supply. ' may lead to large inaccuracies in estimating operating costs, Another factor influencing the installation, of such equip since there may be wide-variations from year to year, and ment is the increasing trend toward the enactment of t&T<*g therefore, average yearly weather records should be used-- and service charges for condensing water wasted into city rather than those for any individual'year. . ' sewers. Certain municipalities will remit the sewer ^xrq If the refrigeration compressor is steam-turbine driven, the same general method can be followed, taking into ac count average water rate per brake horsepower-hour and the cost of steam. . ' - Condenser Wafer - . Condenser-water cost estimates can also be based on equivalent full-load operating^-hours of the refrigeration equipment. The varying temperature of the. water at its source, as well as the temperature of the discarded water, must, however, be taken into account. In general, when water is purchased, control is provided to hold the leaving water temperature (or condensing temperature) constant;and in such case the entering water temperature becomes the major variable. The gallons per minute per ton pan readily be calculated for any water temperature rise- The following equation for cost of condenser water is useful: where B - 0.060 oTH.C (4) B -- cost of water for refrigeration during period, dollars. a ** Average gallons per (minute) (ton). T =* tons of refrigeration at maximum design load. equivalent full load refrigeration operating hours (Table 5). C - water cost, dollars per 1000 gal. Vahmt given ora representative of dkUoroddluoroaethono iiefrigrant 12) reciprocating machinei of about 25 tom capacity m air-condi tioning applications. Requirements of tmaller etocUnes are atzratty higher, and for larger aodunM may be lower. Vohe* drawn ore for liquid re frigerant at condenser temperature (no cubenoting). Subcooting of the liquid may decrease these soloes approximately 0.3 percent to 0,5 permat for each Fahrenheit degree the liquid temperature Is lowered. Fig. 1 .... Typical Brake Horsepower Requirements for Refrigeration" 732 CHAPTER 54 1959. Gota'e or service charge if the condensing water is submetered and discharged into a storm sewer or used for process purposes. Heating The method of estimating fuel consumption to balance the building heat loss is given in Chapter 37. It is important to include the fuel required to heat ventilation air. as used in ventilating and air-conditioning systems. In estimating fuel consumption for ventilation air, the tendency of the conventional control systems to use lea than the estimated quantity of outdoor air in cold weather should be considered in its effect in lowering fuel consumption. In addition, the heat required to accomplish winter humidifying must not be neglected, when this feature is included in the equipment. BIBLIOGRAPHY .W. H. Carrier, R. E. Cheme, and W. A. Grant: Chapter IV (Modem Air Conditioning, Heating and Ventilating, Pitman. Publishing Carp., New York, 1950). ` W. A. Grant: Predicting operating hours of refrigeration equipment used in air conditioning (Refrigerating Engineering, July 1941). R. E. Cheme: Cost of operation of refrigeration used in air conditioning (Refrigerating Engineering, December 1943). Section VTI, Chapter 45, Table 3, 1949 Cost data on variety chain store installations (ASfif? Data Book, Applications Vol ume, 1954-55, American Society of Refrigerating Engineers). (. ; . 7.Ti - -- I; - 'i CHAPTER 55 CORROSION AND WATER-FORMED DEPOSITS, CAUSES AND PREVENTION Oefifl/tions, Classification and Characteristics of Water, Causes and Prevention of Scales and Sludges, Causes and Prevention of Slimes, Underwater Corrosion, Atmospheric Corrosion, Buried Pipe Lines, Handling Water Treating Chemicals, legal Regulations THE purpose of this chapter is to .discuss some of the common problems arising from corrosion of heating is that portion of the total hardness which can combine with the carbonate or bicarbonate ions. The balance of the hardness, principally that which will combine with the sulfate and pnd air-conditioning equipment and to suggest methods ofchloride ion3, is called permanent or noncarbonate hardness. preventing or reducing corrosion. Inhibitor. A chemical substance added to an environment to reduce corrosion. DEFINITIONS Common terms used in the field of water treatment and corrosion are defined as follows: Alkalinity. The sum of the carbonate, bicarbonate, and hy drate ions in water. Other ions such as phosphate or silicate may alan partially contribute to alkalinity. Ordinarily the difference between the total hardness of a water and the al kalinity gives the amount of permanent or non-carbonate hardness present. Anode. A positive electrode toward which negatively charged non-metallic ions migrate and at which reduction occurs in an electrolytic cell. In corrosion processes, the anode is usually the electrode having the greater tendency to go into solution. - Biological Deposits. Biological deposits1 are water-formed deposits of biological organisms or the products of their life proceses. Biological deposits may bo microscopic in nature, such as slimes, or macroscopic, such as barnacles or mussels. Slimes are usually composed of deposits of a gelatinous or filamentous nature. Cathode. A negative electrode toward which positively charged metallic ions migrate and at which reduction occurs in the electrolytic cell. In corrosion processes, the cathode is usually the electrode tending to resist corrosion. Corrosion. Corrosion* is destruction of a metal by chemical or electrochemical reaction with its environment. In the corro sion process, the reaction products formed may be soluble or insoluble in the contacting environment. Insoluble corrosion products may deposit at or near the attacked area, or be carried along and deposited at a considerable distance there from. * Corrosivity. Corrosivity* is tbe capacity of an environment to bring about destruction of a metal by the process of corro sion. Corrosivity is a property of the environment, but it has no significance until the cnetal in question is specified. . Ion. An electrically charged atom or group of atoms. Passivity. The tendency of a metal to become abnormally inactive in a certain environment. pH. The logarithm of the reciprocal of the hydrogen ion concentration of a solution. The pH value denotes the degree of acidity or alkalinity of a solution. The value of a neutral solution, such as pure water, is 7. Values below 7 are increas ingly add, while values above 7 are increasingly alkaline. Polarisation. An effect produced on the electrode of an electrolytic cell by products formed by the passage of current through the cell. Hydrogen is the product generally formed, although other corrosion products may also cause polarisation. Polarization reduces corrosive activity by offering a resistance to current flow and developing an opposing electromotive force. Scale. Scale1 is a deposit formed from solution directly in place upon a <y>nfining surface. It is a deposit which will retain ' Its physical drape when mechanical means are used to remove it from the surface on which it is deposited. Scale, which may or may not adhere to the underlying surface, is usually crystal line and dense, frequently laminated, and occasionally colum nar in structure. ' Sludge. Sludge1 is a water-formed sedimentary deposit. It usually does not cohere sufficiently to retain its physical drape when mechanical means are used to remove it from the surface upon which it deposits. Sludge is not always found at the place where it is formed- It may be hard and adherent, and baked to the surface on which it has been deposited. - Water-Formed Deposits. A water-formed deposit1 is any accumulation of insoluble material derived from water or formed by the reaction of water upon surfaces in contact with water. . Deposits formed from or by water in all of its phases may be further classified as scale, dudge, corrosion products, or biological deposits: - CLASSIFICATION AND CHARACTERISTICS Electrolyte. A solution through which an electric current flows. OF WATER Galvanic Corrosion. Corrosion generally resulting from the contact of two diasimilar metals in an electrolyte. It is charac terized by an electron flow from the metal of higher potential (anode), to the metal of the lower potential (cathode), result ing in corrosion of the anodic metal. Galvanic cell corrosion may also result from the contact of two similar metals in an electrolyte of non-uniform concentration. Hardness. The sum of tbe calcium and magnesium contents in water. It is this hardness that causes the water to resist the formation of soap lather. Temporary or carbonate hardnes Due to the many conditions of water' encountered in in dustry,4 it is frequently necessary to obtain expert advice and a prescribed treatment to make the water suitable for use in a given process. The heating and air-conditioning engineer is concerned chiefly with two broad classifications of water: (1) those waters containing various amounts of mineral impurities and (2) condensates that are relatively free from mineral impurities but contain various amounts 733 734 CHAPTER 55 1959 Guide Table 1 .... Mineral Analyses Typifying Composition of Waters Available and Used industrially in the USA location or Area*'* Unit (11 (21 (31 (4) (51 (61 (71 (81 (91 37 Calcium............... Magnesium......... Sodium................ Potassium........... Ca Mg Na K 6 5 36 62 92 96 3 155 400 1 2 8 18 34 27 2 46 1,300 2 6 7 44 8 183 215 78 11,000 111 1 18 10 3 400 Bicarbonate........ HCOj Sulfate................ SO Chloride............... Cl 14 13 110 202 339 334 549 210 150 10 2 22 135 84 121 11 389 2,700 2 10 13 13 10 280 22 117 19,000 13 Dissolved Carbonate Hardness......... Non-Carbonate Hardness......... CaCO, CaSO, 983 564 948 35,000 12 11 98 165 287 274 172 125 5 7 18 40 58 54 0 295 5,900 * All nlun ie parte per million of the unit cited to Decreet whole Dumber (ace Bcfcreace )._ * Number* iadkete location or area *i follow*: <1} CatrtfU aupply--New York City ft) Swamp Water (Colored) Rlerlr Creek, Middleburt, Florida <l) Ntacara Riecr (TUteted) Niagara FaUs, New York (4) Mlmomi River (Untreated) Averaf* ' (5) Well Water*--Public Supply--Dayton, Ohio--3040 ft ' (S) Well Water--Maywood, niiiu.iii 3080 ft (7) Well Water--SmitbSeld. Va.--33S ft (8) Well Wats--RunnelI, N. Mexico (9) Ocean Water--Aeence of dissolved gases such as carbon dioxide, oxygen, and sulfur dioxide, timt tend to make them corrosive. Dissolved gases are the main factors affecting condensate corrosiveness, but they may also be present in water con taining mineral impurities to an extent that will make the water corrosive. - Mineralized Waters All the waters found in streams, wells, lakes, and the ocean are mineralized. The same is true of all municipal supplies even though they may have been treated. For a given' area, ground waters are likely to be more highly mineralized than are surface waters. Conversely, surface waters are more likely to be contaminated with municipal sewage and trade wastes. Virtually all mineralized waters also contain biologi cal organisms. - Mineralogical Characteristics. The character and amount of extraneous inorganic materials--including deleterious gases--dissolved and suspended therein, describe the miner- alogical characteristics of any water. Revealing such infor mation is the function of a mineralogical chemical analysis. The analyses in Table 1 disclose the composition of the public water supplies used by about 45 percent of the total population of the cities, in the United States, having more than 20,000 inhabitants.* ' All values recorded are in terms of parts per million* * Put* per mOliao are berrimifter ebbrevicted ppa. A part per million ritnific* unit weight cd materiel per million unit weight* ot the eolation. Table 2 .... Conversion Factors for Water Analyses To Coanrl Into Multiply by Grains per U. S. gallon..................... Grains per Imperial gallon............... Grams per liter................................... Mg per liter......................................... ppm ppm ppm ppm 17 14^ 1000 1 This is the approved standard terminology for reporting the results of mineral analyses * Values reported in the other terms commonly used may be converted into the standard form by using the factors listed in Table 2. Data for dissolved gases or pH values have been omitted in Table 1 because even waters of the same mineral contents may vary widely in these respects. Unpolluted natural ` waters usually have pH values within the range 5 to S, de pending upon their free CO* contents. Polluted waters, which include those derived from wells or swarop6 in marshy ground, may have pH values well below 5. Biological Characteristics. The slime-forming organisms are mostly lower plants, grouped by botanists into the phylum thallophyta. This group is distinguished by the absence of leaves, roots, or stems from the mosses, ferns, and seed plants which comprise the three other phyla of the plant kingdom. The thallophyta (see Table 3) are divided into algae, which can synthesize chlorophyll for the production of sugar, and the fungi which lack chlorophyll, and must therefore secure already synthesized carbohydrates. All thallophyta are of universal distribution and many of them are slime-forming. Of the five divisions of algae, only three (the green, the blue-green, and the diatoms) are found in fresh water. Of the five divisions of fungi, all may occur in fresh water, the principal slime formers being indicated in Table 3. . ' . The methods of analysis commonly used in the sanitary examination of a water have, as their principal object, to identify and count pathogens. * Most slime-forming organisms are not pathogens. When a water is subjected to a biochemical analysis for the purpose of evaluating its slime producing characteristics, tests, widely different from sanitary bacteriological tests, must be made. Tests upon the water itself are seldom satisfactory, and true indications of the sliming characteristics of a water'can Phyla Table 3 .... Principal Slime Formers Poogh Orndon of Phyla . Algae Single celled, sometimes forming slimy sheets. Many celled in either sheets or froods. Fungi Bacteria (Schisomycetes) frequently forming slimy surface coatings. Slime Molds (Myxomycetes) forming slimy sheets as one stage of their life history. Sac fungi (Ascomycetes) of which one division, the yeasts, occasionally form slimy aggregates. The alga-like fungi (Phycomyceles) and the stalked fungi (Basidomycetes) rarely form slimes but their filaments may hold together the slimes of other organisms. Corrosion and Water-Formed Deposits, Causes and Prevention 735 only .be determined by the analysis of deposits on surfaces having a temperature, that approximates the operating tem perature range of the final design equipment. The results of such tests are commonly used for selecting proper pre ventive measures. Slime and algae micro-organisms are capable of rapid multiplication and, if not controlled, can cause shut-down or permanent damage to equipment. They can be controlled by chemical treatment of the water or in certain cases by mechanical cleaning of the surfaces affected. The chemicals used are usually toxic, and should' therefore be handled only by trained personnel having a full understanding of the quantity required and their effect on operators as well as surfaces. Chemical treatment is usually preferred to mechanical cleaning particularly where surfaces are inaccessible for cleaning or where a shutdown of the operation is necessary for mechanical cleaning. . ' Condensates All condensates are caused by the cooling of vapor. Con densates resulting from the cooling of water vapor in air are dews, sweats, ram, and snow, while those formed in steamcondensing apparatus are termed condensates or return water. ' In the heating and ventilating field, the biological charac teristics of condensates are likely to be of concern only where the condensate is used as cooling water in recirculating systems. The deleterious gas contents of condensates, how ever, very often' create serious corrosion troubles. The data in Table 4 typify the chemical composition of Table 4 .... Data Typifying the Deleterious Gas Content of Different Atmospheres Air Nano ef Gat ton**, Rural Partial %by proctor* pda Metropolitan %b. Volume Partial Protxwre pdo Oxygen........ Carbon Dioxide... Sulfur Dioxide... 0, CO* so. 21 3.143 0.03 -<T004 None None 21 0.06 0.003 3.143 0.009 0.004 - Rue Gotet Bifum. Coal Fuel OR, Nome of Gat Chemical Partial Partial % by Volume pres sure % by Volume pres tore pda pdo Natural Gat Partial % *>y pretVolume pda - Oxygen........ Carbon Dioxide... Sulfur Dioxide... o, CO, so. 2 0.299 7 1.048 10 1.497 15 2.245 13 1.946 10 1.497 0.07 0.010 0.03 0.004 0.0001 0.0015 Fig. I .... Solubility of Gases at Partial Pressure of 1 Psi the atmosphere in rural and metropolitan areas, and of stack gftRpg when various types of common fuels are used. The curves in Fig. 1 disclose the solubility of the major deleterious gases present in such atmospheres in otherwise pure water, when the partial pressure of the gas is one psia. The most common deleterious gases entrained by steam are oxygen and carbon dioxide. In rare instances, hydrogen sulfide, sulfur dioxide, or ammonia are present. In most steam-condensing equipment/' * the non-condens able entrained with steam accumulate so that the amount present in the vapor space is several hundred times higher than in the incoming steam and the amount dis solved in the condensate may therefore approach, or even exceed for short periods, the amount entrained by the steam. CAUSES AND PREVENTION OF SCALES AND SLUDGES Scales may be formed on surfaces of equipment in contact with water, and sludges in the body of the water, by the separation from the water of dissolved or suspended solids. According to the nature of a particular piece of equipment and the method of its operation, such separation may be promoted by one or more than one, of several factors: a. The concentration of solids may be increased by the evaporation of water. b. The dissolved solids may be rendered less soluble in the water by changes in temperature. - c. Conditions may favor the decomposition of unstable compounds with the formation of less soluble compounds. Figs, 2 and 3 show that the solubilities of both calcium carbonate and calcium sulfate decrease with the rising temperature within a moderate range of temperatures. Sur faces transferring heat into water, such as condensers and 736 CHAPTER 55 1959 Guide -5 oe *> Fl* 3 Adapted from (1) Ind. <fc <w- C**w., 10 (1938) 1197--by Bali*. (1) J.A.C.& SO (1919) 1088--Freer * Johnson. Rg. 2 .... Solubility of Calcium Carbonate in Distilled Water Containing Carbon Dioxide (pH VaJuu af Approximately 73 F) coolers, are more susceptible to scale and sludge formation than are the cold parts of the same system using the same water. The most common of the unstable soluble salts are the bicarbonates of calcium, magnesium, and-occasionally iron. Under conditions favoring the removal of carbon dioxide, as when the water is strongly aerated or when it is boiled, the bicarbonates are readily converted to the relatively in soluble carbonates. The type of scale most usually en countered is calcium carbonate (often called alkalinity) from the decomposition of calcium bicarbonate according to the following chemical reaction: Ca(HCOi)i + heat -* CaCCh + CO, + H# . Calcium Bicarbonate + heat Calcium Carbonate , Carbon Dioxide + water Conversely, carbonates are readily converted to the more soluble bicarbonate,by the addition of carbon dioxide or other acidic materials. This explains the increase in the ap parent solubility of calcium carbonate at decreasing pH values (increasing concentration of hydrogen ion) shown in Fig. 2, the carbonate really going into solution largely as bicarbonate. In special cases, primarily with well waters possessing a high natural iron content, deposition of iron oxide from the decomposition of ferrous bicarbonate takes place according to the following reaction: iFeiHCO*), + 0. - VPt&t + 8 CO, +4 R& Ferrous Bicarbonate + Oxygen Iron Oxide + Carbon Dioxide , water . Low water velocity in heat transfer equipment often causes sludges to settle out in the tubes. This has the same effect-on heat transfer as scale formation. When this oc curs, increasing the water velocity often cures the condition. It is sometimes desired to evaluate the tendency in a particular water toward the separation of calcium carbonate, which may be desirable as a means of establishing a corro sion-resistant film on metal surfaces, or in other circum stances may be undesirable because of the impedance of _ \ a% ' T1 1: OMCTT OCOHCCS Fif. S Adapted (rom Bull. No. IS. Utuv. of ltfinh, Pm iimfi'iin and BmUr ScaUt by P. E. Partridse- Rg. 3 .... Solubility of Caldum Sulfate and of Calcium Carbonate for Comparison ' (CaCOj ut Equifibrara wtft Normal CO} Content of (ho Alntotphero) the calcium carbonate film to heat transfer. This tendency is indicated approximately by the Langelier Index* which is obtained by subtracting the actual pH of a particular water from the pH at which it is estimated precipitation of calcium carbonate would just begin. This estimate-may be made by the use of Fig. 4. . There are various expedients which may be employed for avoiding or mitigating difficulties due to scales: a. The water may be treated before use to remove elements such as calcium, magnesium, and iron, which form relatively insoluble compounds. In the various softening processes this removal of these elements is accompanied by the addition of other elements, particularly sodium, the compounds of which are relatively soluble. b. The water may be treated within the equipment to pro mote the separation of dissolved solids as sludges, rather than as scale which is, in most cases, more objectionable. c. The increase in total solids, due to the evaporation of water, may be controlled by the displacement, continuously or intermittently, of some of the used water by fresh supply. d. Substances, such as the polyphosphates, having the firoperty of inhibiting the precipitation of calcium carbonate rom solutions supersaturated with it, may be added. e. The pH of the water may be lowered (hydrogen ion con centration raised) to reduce the tendency for precipitation of carbonate. This is permissible only to such an extent as will not cause a serious increase in rate of corrosion. The choice of the best expedient or combination of ex pedients must be made for each type of equipment, and will be affected by operating and water considerations. Item c above must be used, regardless of which other items are used, for all recirculating water systems from which evaporation takes place. Once-Through Equipment Where abundant supplies of water are available at low cost, the cooling water may pass through the equipment once, undergoing a rise in temperature. little difficulty from scale should be encountered if the Langelier Index is lower than +05, based on the highest water temperature en countered in the system. This often corresponds to a car bonate hardness of less than 200 ppm when water tempera tures are lower than 100 F. However, since many municipal supplies are softened so that incipient calcium' carbonate COLUMN 5 Corrosion and Water-Formed Deposits, Causes and Prevention 737 738 CHAPTER 55 . 1959 Guide precipitation is induced, the Langelier Index is a more re liable indication of scaling tendency. Prevention of scale in once-through systems is based pri marily on the adjustment of pff, the application of surfaceactive agents, or a combination of the two. Normally tbe addition of a few parts per million of a surface-active agent such as a polyphosphate" fed proportionately to a water with a scaling tendency is ail that is required to control scale. Where a given water does not respond satisfactorily to surface-active agents, reduction of pH with sulfuric acid or carbon dioxide is often employed. The pH is reduced only sufficiently to have it fall within the effective range of the surface-active agent. The use of scid or carbon dioxide is sometimes permitted without polyphosphates when corro sion will not be severe. In this case the pH is reduced so that the Langelier Index is less than -fOh. The add or car bon dioxide must be added with care. Use of automatic pH controllers is required if corrosion is to be prevented. A special case of scale from ferrous bicarbonate decompo sition was mentioned previously. Ferrous bicarbonate is con siderably less stable than calcium bicarbonate. The preven tion of this decomposition can be accomplished by the addition of polyphosphate in low concentrations.0 The use of polyphosphate in the ratio of two parts by weight to one part by weight of iron is usually most effective. The polyphosphate must be added to the water before exposure of tbe water to air or chlorine if effective stabilization of the iron is to occur. Closed Recirculating Systems Tbe closed recirculating system is one in which water drculates through one heat exchanger where it absorbs heat, has its temperature elevated, and circulates through an other heat exchanger in which its temperature is lowered. In cold water or chilled water systems scaling is seldom a problem. In hot water systems scaling is seldom a problem unless there is a large amount of make-up water." In this case surface-active agents such as polyphosphate are used. . Open Recirculating Systems ' Where water from condensers and similar equipment is passed through a spray pond or cooling tower and then returned to the equipment, there is an increase in the con centration of solids because of the evaporation of some of the water into tbe cooling air, and, moreover, the aeration removes carbon dioxide. Both factors promote the tendency to deposit scale. Tbe corrosive properties of the water can also be increased through tbe absorption of add gases such as sulfur dioxide (SO,), from the dr." The absorption of gases from the air being processed and the concentration of solids due to evaporation are factors in air washer operation when the air is humidified. The concentration of scale-forming minerals in open re circulated cooling water is limited by natural drift or wind age loss. This is the loss of water droplets from the system. Windage losses from typical systems may be classified as folloWs, based on recirculating rates: colaCQf Rato Evaporative Condensers and Air Washers..............0 to 0.1 Mechanical.Draft Cooling Towers...................... . Q.l to 0.3 Atmospheric Cooling Towers....... .............................0.3 to 1.0 Spray Ponds.................................................................. 1.0 to 5.0 To show the effect of concentration in a typical mechani cal draft system assume: 1. Recirculating rate = 100 gpm. . 2. Drift loss -- 02 percent of recirculating rate " 0.2 gpm. 3. Evaporation rate 1 percent of recirculating rate -- 1.0 gpm. 4. Calcium bicarbonate in make-up water -- 100 ppm. 5. Calcium bicarbonate in evaporated water = 0 ppm. Let K = concentration of calcium bicarbonate in recirculat ing water -- concentration of calcium bicarbonate in drift loss. Tbe process of concentration in the system may be repre sented diagr&mmatically as follows: Evap- = 1 gpm Ca(HCOi)t " 0 ppm _________ 1____________ Recirculating Water System K " Ca(HCOj)t cone. Drift 012 gpm * Ca{HCOt)t " K ppm T Make-up 1.2 gpm Ca{HCOi)t 100 ppm The concentration may be obtained from the equation (Make-Up)[Ca(HCOj)t cone.) = (Evap.)[Ca(HCO*) cone.I -HDrift)lCa(HCOi)* cone.) (1.2) (100) - (1)(0) + (0.2)(K) substituting, 120 - 0 + 0.2 K whence, K = 600 ppm Therefore the concentration of calcium bicarbonate in the recirculating water equals 600 ppm. This far exceeds the allowable concentration of 170 ppm at which scaling will occur. . To correct this situation, it is imperative to provide a continuous bleed-off or blowdown from the recirculating water circuit. Typical bleed-off requirements are shown in Fig. 5. Reference to the No Treatment curve shows that a Fig. 5 .... Relation of Bleed-Off Requirement to CaCOj in Make-Up Water Corrosion and Water-Formed Deposits, Causes and Prevention 739 bleed-off rate of 12 times the evaporation rate is required when a make-up water contains 100 ppm calcium bicar bonate (or alkalinity) if scale is to be prevented. Calcula tion by a material balance will show that the bleed-off plus drift loss will limit the calcium bicarbonate to 171 ppm. It can be seen from fig. 5 that very large amounts of bleed-off are required as a make-up water approaches or exceeds 150 ppm of alkalinity. When alkalinity exceeds 175 ppm, bleed-off alone is no longer effective. The use of 5 ppm or less of polyphosphate is extremely effective in re ducing the required bleed-off and making possible the use of make-up waters which will not respond to bleed-off alone. Occasionally, waters are encountered which have excep tionally high alkalinities or which develop high pH values when recirculated. The use of sulfuric acid is common in these cases to maintain pH values between 7 and 8. Poly phosphates are most always used when acid is required. It is very important to control Mid feeding carefully to avoid serious corrosion. Automatic pH controllers are often employed for such a purpose. Heafing Systems In hot water heating systems or in steam heating boilers where all condensate is returned, troubles from scaling should not be severe. If necessary, sodium phosphate or sodium earbonate may be added to the water to prevent the formation of adherent calcium sulfate scale. Boilers and High Temperature Equipment Where temperature exceeds 250 F, complete softening of the water is the only practical method for minimizing sludge formation. This is usually accomplished by artificial or natural zeolites (called also ion-exchange materials) or by hot-process precipitation softeners- In boilers operating at pressures above 100 psig virtually all the calcium, magnesium, silica, iron, and manganese salts ' entering with the feed water are potential scale or sludge formers. * In boilers operating at 100 to 250 psig, the formation of adherent calcium sulfate (anhydrite) scales is most to be feared. Such deposits form on the hottest evaporative sur faces. The scale has a low heat conductivity. Even a layer of egg shell thickness may so impede the rate of heat trans fer as to bring about over-beating of the metal. Tbe orthophosphates of sodium are most frequently used to prevent sulfate scales. The concentration of phosphate required is such as to cause the precipitation of calcium phosphate as sludge, thus keeping the boiling water under saturated with respect to calcium sulfate. To a lesser ex tent, sodium carbonate (called also soda flgh and sal soda) is also used. Most of the effective boiler compounds contain either phosphates or soda ash, or both. Certain organic ma terials and colloids are sometimes found to mirmnia*- scale formation. Where chemicals are introduced directly into the boiler in amounts adequate to prevent scale, sludge is formed in amounts proportionate to the and mag nesium salts entering with the feed water. To prevent troublesome accumulation of this sludge, as well as soluble salts, as evaporation occurs, some blox&down of boiler water is necessary. CAUSES AND PREVENTION OF SLIMES A water containing dime-producing organisms will pro duce prohibitive amounts of slime only when the conditions of use are such as to propagate their life processes. Whenever sufficient food material from normal water or from airborne > dust combines with optimum temperature conditions, such as exist on cooling surfaces and air washers, serious quanti ties of slime will be produced. Some natural well waters do not contain sufficient foods to support luxuriant slime growths. Algae, which require light for carrying on their life processes, are likely to cause difficulty in cooling towers and other areas where sunlight is abundant. The ordinary slime-forming bacteria are capable of using a wide variety of nitrogenous and cellulose material as food sources. These bacteria thrive best under dark conditions such as exist in condensers and other beat transfer surfaces. Other organisms capable of causing similar difficulties use such a wide variety of food material as algae," iron compounds," and inorganic sul fates." At present, tbe use of toxic chemicals and irradiation are the two general means employed in dime control. The value of ultra-violet light, used so broadly in the beverage industry, -is somewhat in dispute. Anti-fouling paints have been developed and are fairly satisfactory for the prevention of the growth of macro- Tabte 5 .... Common Chemicals Used for Slime Control ChemrcaS Trxtdt Haot Pbyticai SW* Chlorine Hypochlorites Chlorinated Phenols . Sodium-- Potassium Per* manganate Copper Sulfate,, Chlorine Calcium Hypochlorites Sodium Hypochlorites Chlorophenylphenate Tetrachlorophenate Pentachlorophenate Permanganate of Potash Blue Vitriol Gas Crystalline Briquettes Briquettes Briquettes Crystalline Crystalline * A Shipped. organisms such as barnacles and mussels, but these paints must be renewed at frequent intervals, and are not appli cable to inaccessible areas such as the inside of pipe lines and cooling towers. Satisfactory anti-sliming paints have not been found. Names and other pertinent data relating to some of tbe more common chemicals used in slime control are shown in Table 5. Chlorine is the only chemical to which is attributed the ability to destroy slime-forming organisms. The others are presumed to poison marine organisms, most of which recover when the chemical is not used regularly. - While chlorine is the most generally used ehemical, the use of others may occasionally prove to be more practicable. Choice of the chemical is conditioned largely by the design and operation of the system. Open Recirculating Systems In spray ponds and cooling towers of the open type, light-loving algae growths are likely to cause blocking of tbe distribution piping and troughs. These organisms are most troublesome in areas accessible to sunlight Algae slimes are usually stringy in character. In open recirculating systems, continuous use of small quantities.of chlorine is generally most satisfactory. In once- , 740 CHAPTER 55 1959 Gvidi through systems, where large quantities of water are used, intermittent treatment a few times each day will usually result in satisfactory slime removal and chemical economies. Neither the phenols nor copper sulfate' may be used for the removal of slime already formed. For this pur pose, chlorine gas or suitable chlorine liberating compounds may be used. After being cleaned, the other chemicals may be used to prevent the reestablishment of slime in the system. The removal of green algae from a cooling tower should never be used as an indication that the true slime forming organisms on heat exchanger surfaces have been removed. The more resistant slime formers, which so ma terially reduce heat transfer efficiency, will often be un affected by treatment which completely eliminates algae. Copper sulfate must be used with care because it can cause serious corrosion of steel in a system. It is also in effective in alkaline water because the copper is precipitated from the water. Gosed Orce-Through Systems In equipment where light is excluded, slime formations are due to fungi. Usually, they predominate on the heat exchange surfaces. Bacteria form thick, soft slime. Yeast and molds form tough rubbery slimes. Chlorine and hypo chlorite solutions, fed intermittently, are usual preventatives. UNDERWATER CORROSION When deleterious substances are present in water, the corrosivity of the solution is increased in proportion to the amount of deleterious substances present, the tem perature, and usually the rate of flow of the solution over the metal surfaces. There are other relevant factors, but their influence in general is subordinate to those mentioned. Dissolved oxygen, acid gases, and chloride salts are the corrosion accelerators most frequently encountered. Neutral and. slightly alkaline waters saturated with air, corrode iron at a rate about triple that for the same water free of air. Hot water containing oxygen will corrode iron at a rate three to four times that for the same water when cold. Corrosion of iron decreases as the pH of water solutions increases, and practically ceases at a pH of 11. Film forming agents such as chromium, nickel, and silicon, can be added in the manufacturing of metals to provide increased corrosion resistance. In some processes, inhib itors, such as chromates, can be added to the water to minimize corrosion. Soft water, as for example the effluent from zeolite softeners, is likely to be several times more corrosive to iron than hard waters. In small installations, the use of copper or brass pipe usually is a practical expedient. Ce ment-Lined pipe and tanka suitably resist attack. Where the water contains slime-forming organisms, espe cially those bacteria that thrive on iron, chlorination of the water is imperative to inhibit tuberculation and subsequent pitting. Bitumastic paints, applied at regular intervals upon well cleaned surfaces, will measurably prolong the life of equip ment handling cold waters. It is generally agreed that the rate at which oxygen reaches the surface determines the rate of corrosion of ferrous metals. Underwater, the oxygen diffusion to a surface is often restricted by films and scale that form on the surface, and consequently the rate of corrosion differs from that of surfaces exposed to the atmosphere or to alternately wet and dry conditions. All ferrous metals will not corrode at the same rate. A thorough knowledge of the conditions to be encountered and experience gained from tests of the materials in service are required when attempting to predict performance or life in a given service. ' Copper, aluminum, and other non-ferrous metals and their alloys have been found effective in resisting many types of underwater corrosion. Corrosion of ferrous metals with which these metals are in contact, may be accelerated in water of good conductivity. ' The environmental conditions are responsible for length of service of any metal. No single material is suitable for all types of service. Once-Through Systems Where corrosion can be expected in once-through systerns, it may be minimized through the use of one of the following methods: 1. Forming a protective film of calcium carbonate on the metal surfaces. 2. Providing mechanical or ehemic&l deaeration, or both, of the water. 3. Using organic or inorganic corrosion inhibitors, or both, in low concentrations. Formation of a thin protective calcium carbonate film is accomplished by adjustment of the water until the Langelier Index has a value greater than +0.5. This is rather difficult in systems which have a wide variation in temperature. Since the Langelier Index is dependent on temperature, when a water is adjusted to form a protective film on those surfaces of higher temperature, no film will form on colder surfaces. Therefore, this method of corrosion control is more applicable to large municipal distribution systems. Where heat transfer is involved, the method is usually unpractical except 'under unusual circumstances. When this method is used, pH is increased by using an inexpensive alkali such as lime, caustic soda, or soda ash. Lime is usually used for waters of low <*1<+tTn content. Caustic soda or soda ash are used for waters of high calcium content. Mechanical1* and chemical deaeration are not often used in once-through systems because of relatively high operating costs. Mechanical deaeration nlsn requires the use of costly equipment. Chemical deaeration is usually accomplished by raising pH with caustic soda and by continuously feed ing catalyzed sodium sulfite' in proportion to water flow. The use of catalyzed sulfite is not permitted in water to be used for potable purposes. . There are several corrosion inhibitors such as chromate, polyphosphates, and silicates which are effective in once- through systems." Polyphosphate at a concentration of 2 to 5 ppm has been found useful in controlling tuberculation of iron pipe and in reducing overall corrosion. Usually, more effective treatment is to use chromate polyphosphate at concentrations of less than 60 ppm. Sodium silicate is often used in relatively soft waters by increasing the silica content about 8 ppm. It is used pri marily to reduce corrosion in potable water supply systems. Open Recirculating Systems Corrosion in open recirculating systems, such as air washers and cooling towers, is usually controlled by use of Corrosion and Water-Formed Deposits, Causes and Prevention 741 corrosion inhibitors such as chromates, polyphosphates, a Brines. Refrigerating brines usually are comprised of so combination of chromate and polyphosphate, and nitrites."'** dium chloride, calcium chloride, or calcium and magnesium Mechanical or chemical deaeration is not practicable in open chlorides. The corrosivity of dilute brines is higher than systems because of the high rate of aeration. It is not practica their more concentrated solutions. -The corrosivity of sodium ble to use high pH values of 11 or more in systems containing brines, other conditions being fixed, is about 15 times greater wood. High pH will cause serious delignification of wood. than brines of the alkaline earth metals. High pH values prevent control of scale. Corrosion con Brines are excellent electrolytes. Contact of dissimilar trol is usually carried out in the pH range of 6.5-8. metals of wide potential differences, when in contact with Chromates are by far the most effective corrosion inhibi brines, results in rapid corrosion by galvanic action. tors. It is extremely important, however, to maintain an The leakage of air, acid refrigerants, or both, accelerates adequate concentration of 300-500 ppm, which is effective the corrosivity of brines. Ammonia precipitates calchun and for most systems. If for economic reasons substantially lower magnesium salts, thus clogging the system at restricted concentrations are used, serious pitting corrosion may occur. points. " Polyphosphates are most effective in reducing tubercula The addition of caustic soda and sodium dichromate to tion. It is not usually possible to reduce overall corrosion to brine solutions to inhibit corrosion of iron, is a more or less anywhere near the degree possible with chromate. general practice. Sodium silicate and sodium phosphate are Where economy of treatment is of primary importance, a also used at times, but tests indicate they are not as effective substantial reduction of pitting and overall corrosion can be as is sodium dichromate. It has been suggested" that 125 lb obtained by using as little as 60 ppm of a mixture of poly of sodium bichromate per 1000 cubic feet of calcium chloride phosphate and chromate. Close control over pH is a re brine, and 200 lb per 1000 cubic feet of sodium chloride brine, quirement for good corrosion control by this process. be added to inhibit brines; that when salt or calcium chloride Sodium nitrite has not had widespread use as a corrosion is added to "strengthen" brine, sodium dichromate also be inhibitor in open recirculating systems. It has been reported added in the amounts shown in Table 6. that difficulty may be encountered in maintaining effective concentrations. Considerable' field experience is needed to further qualify this inhibitor. - Table 6 .... Quantifies of Sodium Dichromate to be Added to Maintain Initial Concentration . Closed Recirculating Systems The term Closed Recirculating System is in reality a mis Spedfie Gravity of 8/ino to bo Sfrongtiwood . lb Sodium Dichromate per 100 lb Cod, Added nomer. Except for relatively gmall systems, most closed sys tems are open because they most usually require make-up water. Recently, tests conducted on 84 closed- systems indi cated that more than 50 percent of the systems had one or ' more water changes per month because of leakage. Weekly water changes were found in more than 10 percent of the 1.16 1.18 1.20 1.22 1.24 0.695 0.621 0.556 0.502 0.455 . systems." Continuous make-up, of course, replenishes oxygen-in the system, thus promoting corrosion. It is imperative, therefore, that corrosion control be provided for most closed lb of Sodium Dkhrotoale per 100 lb Nod Added systems. The age old assumption that closed systems are closed is no longer valid. - Corrosion control is usually accomplished by (1) mechani cal or chemical deaeration or (2) use of corrosion inhibitors such as chromates and nitrites: 1.12 1.14 1.16 1.175 1.79 1.47 1.32 1.18 The use of polyphosphates is not generally recommended for closed systems because thgy- will revert to ineffective orthophosphates unless there is a large replacement of water 1 Refrigerants* The common refrigerants, except those of containing polyphosphate. . . the hydrocarbon type, will attack the common metals and Higher concentrations of chromate are usually maintained alloys if moisture is present. Even a very small amount of in closed systems as compared -with open systems. This is water may cause severe corrosion with certain refrigerants. primarily due to the fact that, since water losses are usually The amount required need only be sufficient to produce a small, the cost of maintaining excess chromate as a safety water film on the metal-surface. - -' factor is small. . ' With the haiogen&ted hydrocarbons, complete elimination Treating Chemicals .. of water is much to be.desired. Where ammonia is used, copper and its alloys, - aluminum and zinc, are- attacked Whenever chemicals are used to control scale, corrosion, algae, and slime, competent advice from a water chemist is desirable. Often factors considered irrelevant to the layman, will be of much importance in securing effective treatment. especially at elevated temperatures. When sulfur' dioxide is used, more than 50 ppm .(0.005 percent) of water will cause appreciable corrosion of virtually all the common ma terials. ' Very often troubles are created through improper use of chemicals and are more serious than if- they were not used.** Minimizing Steam Condensate Corrosion ' . .. Refrigerating Systems Corrosion in refrigerating systems is confined to surfaces in contact with brines or those in contact with refrigerant. . - There are four expedients that may be utilized to minimize corrosion in steam condensate systems: (1) treatment of the boiler feed water 6o-as to eliminate deleterious gases en trained with the steam, (2) design of the condensing equip- 742 CHAPTER 55 1959 Guide ment to minimise dissolution in the condensate of the dele terious gases entrained with the steam, (3) chemical treatment of the condensate, (4) use of resistant metals. . Boiler Feedwater Treatment. Elimination of oxygen from boiler feedwater and, therefore, from the steam developed, can be accomplished either mechanically or chemically. In some steam generating stations, both expedients are em ployed. Tests** have indicated that in small low-pressuie heating boilers, where the boiler input contains less than about 50 ppm of carbonate hardness, the CO, in the steam can be controlled by adding calcium hydroxide to the boiler. In Fig.. 6 are shown the equilibria conditions proposed. for boilers operating at pressures .up to about 5 psi gage. This Fig. 6.____ Relation of Hydrate/Carbonate Content in Hard Boiler Water and CO* in Steam at About 5 Psi Operating Pressure expedient may not be used in higher pressure boilers, because of the possibilities of scale and sludge formations. In the latter, the only method used to date for treating the feed water consists of removing the alkaline earth salts, i.e., softening, and subsequent addulation followed by deaeration at temperatures near the atmospheric boiling point of water.** . Design of Condensing Equipment. In the design of water heaters and comparable types of condensing equipment,** it is possible to shift the accumulation of non-condensable to a location away from the condensate level and, subse quently, vent these gases to the atmosphere. The venting of an amount of steam equal to about one?half-' percent of the total steam entering the condenser is the optimum vent rate. -Venting is of little practical, value when the CO, content of the, infffiming steam is below about 5 ppm. When the steam, contains more than 5ppm, venting provides a means of producing a condensate containing a minimum .of about 3 ppm. However, even as little as 3 ppm of dissolved CO, can produce active corrosion if large amounts of condensate are flowing.-; . ' . '*; Chemical Treatment of Condensate. Condensates con taining comparatively large amounts of oilj are practically non-corrosive, due to the protective film provided by the oil: When oil is intentionally added to condensate,1* inadequate quantities may accelerate rather than decelerate corrosion on those surfaces not covered by the oil. Sodium silicate added to C0,-bearing condensate has been shown to decrease, but not entirely prevent, corrosive action. It is not known whether the protection afforded by silicate solutions is due to the establishment of a protective film on the metal surface or to neutralisation of the CO, by the alkali in the silicate solution. It has been postulated that ammonia,1* cyclohexylamine ethylene diamine, and morpholine*1 will retard corrosion of condensate lines. Tests with benzylamine have also been re ported.*1 Where copper and its alloys are involved, the use of . alkaline inhibitors is believed inadvisable. The use of small amounts of sodium hexametaphosphate has been suggested too, but tests** indicate that this salt accelerates rather than decelerates, the rate of attack on steel by condensate con taining CO, and oxygen. Whether chemical treatment of steam or condensate is feasible, must be determined not only upon the basis of the acuteness of corrosion troubles, but also upon the uses made of the steam or condensate. Use of Resistant Metals Steam condensates vary greatly in their ability .to corrode metals. The amount of gases that have been dissolved are the determining factors, with oxygen and carbon dioxide, which turns to carbonic acid, being the most common. Steel, wrought iron, and copper are the metals ordinarily used for pipelines carrying steam condensate. All of these materials have been used with various degrees of success, but under severe corrosive conditions only a few years of service can be anticipated. With the proper metal or alloy carefully selected to suit the existing corrosive conditions, a service life of 15 to 20 years or more is not at all unusual. To obtain, a long service life, an analysis must be made of the existing conditions, and if the condensate contains undue amounts of oxygen, carbon dioxide, and other harmful impurities, me chanical elimination of these gases should be a requirement. Treatment of the boiler water and the condensate itself has also proved to be somewhat effective. Copper and ferrous metals are attacked by combinations of carbon dioxide and oxygen. When the condensate is being returned to the boiler, any copper corrosion products in the water occasionally present a serious problem. The copper that goes into solution is carried along in the condensate, and upon reaching ferrous materials in the boiler and elsewhere will plate out on the ferrous surfaces and set" up galvanic corrosion due to the contact of Higgimilnr metals. One of the most successful means of preventing corrosion near the junction point of copper and ferrous piping, or where copper piping is connected to steel tanks or boilers and other ferrous vessels, is to install a throw-away section at or near the junction. Since the corroding effect will always be -found on the ferrous side of the junction rather than on the copper ot copper-alloy tide, and the' effect is utiially localised in the immediate vicinity of the joint, the installa tion of a ferrous pipe section 8 to 10 in. long will absorb practically all of the corrosion. When this throw-avay sec tion becomes corroded, it can readily be replaced. It should be noted, however, that in ordinary hot water heating sys tems this problem of potential corrosion at junctions of dis similar metals seldom presents itself- Where there is any suspicion in this regard, precaution can be readily and com monly taken by separating the two metals electrically by means of a simple insulating union. Corrosion and Water-Formed Deposits, Causes and Prevention 743 No paint or similar protective coating has thus far proven satisfactory where dissimilar metals are used in the same condensate pipe runs. .Tests of cement-lined and vitreouslined pipe have shown the linings to be readily dissolved by the hot condensates. At condensate temperatures, galvanis ing on iron or steel pipe has not proved to have any ad vantages, and in some cases has been found to be detrimental. ATMOSPHERIC CORROSION Most of the problems originated by atmospheric corrosion occur in connection with the fire-tide of boilers and furnaces (including their flues and stacks), sewer vents, air ducts, and coal and ash handling equipment. Usually such equip ment is fabricated from common types of ferrous metals. Generally little or no atmospheric corrosion occurs at tem peratures higher than the boiling point of water; because at such temperatures little or no condensate is formed. If it does form at the higher temperatures; only' negligible amounts of carbon dioxide and oxygen present in the atmos phere, will dissolve in the hot liquid, but sulfur gases may dissolve and cause rapid attack. Oxygen, sulfur dioxide, sulfur trioxide, and carbon dioxide are the deleterious gases most frequently accountable for corrosion in moist atmos pheres. Coal Storage and Handling Equipment -periodically applying .paints such as those specified in the following paragraphs entitled Air Ducts. . Air Ducts ' ,` The most practical method for protecting air duct sur faces made of steel from.atmospheric corrosion, is to apply- protective paints. One of the most effective protective coat ings is red lead paint. -- Three coats of paint should be applied, of which the first two coats should be rust-inhibitive paint such as red-lead paint, with the second coat tinted to a light brown color with carbon black, and the finishing coat may be red lead paint tinted to a black or.brown color, black paint made ac cording to Federal Specification TT-P-61, red iron oxide paint conforming to Federal Specification TT-P-31, or white or light tinted paint made according to Federal Specification TT-P-40. ' Another paint which has had some use for priming iron and steel is zinc chromate paint. > Under some conditions, a chlorinated rubber base paint made according to Federal Specification TT-P-91 may be used for the finishing coat, particularly, where the presence of highly corrosive gases or contact with strong alkaline, water would injure the standard paints. Rubber base paints should be used only for the finishing coat over regular priming and second coats. - Virtually all coals contain sulfur in the form of pyrite, and some moisture. In storage, the pyrite is likely to be de BURIED PIPE LINES composed by oxidation. Moisture dissolves the products of lines that are cold and in intimate contact with the decomposition forming sulfurous and sulfuric acid. The earth are corroded from the same causes as in mineral add solutions vigorously attack the supporting metal. . waters, but pitting is usually more intense due to variations Rubber linings have been developed for coal chutes and in concentration of salts and oxygen in solution, acidity, bins to effectively resist corrosion and the abrasive action of drainage, and presence of solid materials (such'as cinder) in the coal, but they are expensive.*4 Concrete linings for steel contact with metal pipe. Galvanie currents, induced by con bunkers have also been effectively employed.** --- tact of certain dissolved constituents in the .soil, often act The use of high chromium steels is not always a sure' over a large area, and accelerate corrosion where they leave cure, especially with coals treated with dust-allaying agents the pipe line. ` ' high in chlorides. ' Certain bacteria that thrive in the absence of oxygen Flues, Stacks, and Fire-side of Boilers have the power to obtain' hydrogen and dissociate sulfates in the soil, with a resultant production of hydrogen sulfide The surfaces of flues and boilers contacting the products of combustion, seldom experience corrosive attack when the equipment is in operation. Breechings, smoke hoods, and canopies in contact with flue gas-may, however, be subject to attack during the warming-up period of an appliance, or which attacks iron to form iron sulfide. - Stray electric currents from electric - power generating stations sometimes find their way into buried steel struc tures, and do damage in proportion to the current density where the current leaves the metal to enter the ground: when the rate of operation is so low that the temperature of the flue gas is below the dew point. It is common practice Pipe Materials to use cast-iron or acid-resistant vitreous enameled steel in Some underground corrosive environments found in the flue gas connections to appliances, to prolong the life of these air-conditioning and heating industries require special ma parts. The shut-down period, when .condensation of moisture terials. The selecton of such materials must be based'upon occurs on the metal surfaces, is usually the time when most an economic evaluation, as the use of expensive first cost damage is done.** In those sections of the stacks where flue materials is not wise if the life of lower cost materials is gas temperature drops below the dew point, corrosion is inevitable during operation. adequate. On the other hand, a material low in cost and corrosion resistance should be avoided if it leads to costly It is clear that where long shut-down periods are antici shut-downs, repairs, and early replacements. Underground pated, a practical method for mitigating corrosion is to clean piping materials should be selected for their ability to resist the surface thoroughly and to provide adequate clean, dry exterior as well as interior corrosion, and careful evaluation air circulation to prevent condensation. (See also Care of . Idle Heating Boilers, Chapter 35.) of the soil and water should be made. ' '' Underground corrosion of metals is particularly difficult Protective coatings with organic binders are destroyed to predict. There are many different types of soils varying rather rapidly above 400 F because of the decomposition- of in composition and in ability to corrode both ferrous and the organic materials. The surfaces of metals, whose tem non-ferrous metals. Where excessively corrosive soils are perature does not exceed 400 F, may be protected by encountered, special materials may be necessary, but gener 744 CHAPTER 55 . 1959 Guide ally the commonly used ferrous materials have proved to be the most economical. Copper and many of its various alloys are used advantageously, but their use is more restricted to selected localities. It has been found that soils with high content of organic matter or alkaline soils in which the ratio of chlorides and carbonates to sulphates is high, may be corrosive to copper." Copper or the commonly used ferrous metals should not be embedded directly in cinders or in tidal , marshes, as they may be unduly attacked by sulphur com pounds. It is also wise to avoid the embedding of any pipe materials in soils where unusually high salt contents are known to exist. Galvanized wrought-iron pipe and steel will resist under ground corrosion quite .satisfactorily, particularly if the gal vanized coating is 3 oz per sq ft or more. The National Bureau of Standards reports that where an underground piping material contains 3 oz of galvanizing per square foot, or more, the life of the pipe materially increased. The zinc used for galvanized coating is on the electrochemical pro tective side of the iron; and the zinc as it corrodes is changed to zinc compounds before the underlying base metal is at tacked. This fact and the mechanical protection provided by the zinc coating account for the protection afforded by the galvanized coating. Once the galvanized coating has been destroyed, the base metal must then retard .the corrosive attack, so the rate of attack depends upon the composition of such base metals. Lead-coated pipe** has had a limited application for underground service. It has been found that it corrodes chiefly in soils deficient in oxygen or containing cinders. - Protective Coating ... Protective coatings for buried pipe lines are in a class by themselves because of the unusual service conditions, and be cause it is not possible to maintain them by recoating when necessary. Buried steel pipe lines have been protected against corrosion with considerable success by the use of very thick bituminous coatings applied in molten condition. The best results .are obtained by applying the bituminous coatings over a standard priming coat such as red lead or a bitumi nous paint, and for long-service it has been found that after the bituminous coatings are applied, a wrapping of asbestos fabric saturated with bitumens will prevent movement and displacement of the bituminous coatings, and add greatly to the length of time satisfactory protection will be main tained. Cathodic Protection Protection is obtained by rendering the structure cathodic to the surrounding water or soil by means of a controlled difference of potential. This method, which has proved satis factory and economical on a number of gas and oil pipe lines underground, has also been applied with some success to the protection of the inside of water-storage tanks and other structures that are in contact continuously with water. Pro tective coatings that insulate a large portion of the metal surface will reduce very materially the total amount of pro tective current that must be impressed on bare anodic areas to arrest corrosion. .. Because of differences in environmental conditions, it is necessary, to determine or estimate the minimum current density required for each structure, and design the anode or . anodes so that the necessary protection can be obtained most economically. In water having relatively high electrical con ductivity such as in sea water, this is comparatively easy compared with fresh water. In the latter, the composition of the water is a major factor. It is therefore desirable to ob tain an accurate estimate of the minimum current density required. The current is then controlled by the potential be tween the anode and the structure to be protected. Rectifiers have generally proved to be the most practical means for supplying the necessary current for protection of surfaces in contact with neutral waters." HANDLING WATER TREATING CHEMICALS Virtually all the chemicals used in water conditioning are injurious if taken internally in large doses. Many also cause severe skin irritation. Thus, they should be handled with caution. . Caustic soda, hme, and concentrated sulfuric acid will bum the flesh. In addition, if mixed with small amounts of water, sufficient heat may be generated so that spattering occurs or the container becomes too hot to handle. The chlorophenol compounds, even in the low concentra tions used in water conditioning, have been reported** to produce dermatitis. Chrom-itcb is not uncommon among workers handling chromates. The amines are said to be ab sorbed through the skin.u Morpholine is said to cause kidney and lung trouble when so absorbed. Chlorine gas irritates the skin, eyes, and mucous mem branes. Concentrations, as low as 0.004. percent by volume in air cause dangerous illness in one-half to'one hour. When relatively large amounts of the non-gaseous chemi cals are to be handled, protective clothing, including goggles, should always be provided, and a shower head or its equiv alent provided at or very near the point where the nhnmVflh are mixed. Chemicals should always be washed from the skin with large volumes of water. For the Handling of chlorine and chlormators, the U. S. Public Health Service" stipulates the following safety re quirements: 1. Suitable gas masks and a small bottle of ammonia for testing for leaks should be kept at convenient points imme diately outside the room or enclosure in which chlorine is being stored or is in use. Gas mask* should be inspected at regular intervals and kept in serviceable condition. Note:--All purpose masks offer adequate protection only when the concen tration of acid gases does not exceed two percent--see Safe Practices Pamphlet % 64 National Safety Council. 2. Chlorinating equipment and cylinders of chlorine should be housed preferably in separate buildings above the ground level. 3. Hie room or building housing chlorinaters in service should be maintained at a temperature above 60 F, but never in excess of the normal summer temperature. The cylinders of chlorine should be shielded, where necessary, from excessive heat or cold. Direct heat should not be applied to cylinders of chlorine, nor should hot water be poured over them or come in contact with the cylinder valve. 4. Adequate ventilation should be provided for all enclosures in which chlorine is being fed or stored. 5. All joints of tubing connecting chlorine cylinder and chlorinators should be kept absolutely tight and inspected frequently to insure tightness. Tubing should slope upward from the cylinder. LEGAL REGULATIONS . In a number of states, the water used for humidification, even in industrial plants, is required to meet drinking water standards insofar as bacteriological quality is concerned. A ruling of the TJ. S. Department of Agriculture, Meat Inspec Corrosion and* `Water-Formed Deposits, Causes and Prevent:*** 745 tion Division, prohibits the use of chromate in water used for air washing when the air later contacts foodstuffs.** There is an ever growing consciousness on the part of public health officials, of the necessity for regulations to protect potable water supplies. Attesting this is an ordi nance** now in effect in Detroit, Michigan, which stipulates . in part: "No physical connection shall be maintained between lines carrying city water and pipes, pumps, or tanks supplied from any other source. Where dual supplies are necessary or desired, lines carrying city water must be protected against back Sow of polluted water by an atmospheric gap. Secondary supplies and emergency sources shall include: surface waters from rivers, lakes, ponds, lagoons, and reservoirs; well waters both deep and shallow- any supply of water which has been stored, held, or reserved after being used for industrial purposes; cooling water, or water which has in any way been treated, processed, or has been subjected or exposed to any contamination of a bacterio logical or chemical nature; and water'from any other source than the city supply." The U. S. Public Health Service stipulates: "Salts of barium, hexavalent chromium, heavy-metal glucosides, or other substances with deleterious physiological effects, shall not be allowed in the water supply system." Table 7 .... Recommended Maximum Allowable Content in Water Supply* Svbsfonea Max. Concafttratioa, ppm Ijm(1 0.1 1.0 0.05 * U. 8. Public Health Service. 0.001 10.6 The same agency recommends that the concentration of . the substances listed be held below the values cited in Table - 7. The Board of Directors of the-American Water Works Association has accepted these values as standard for all public water supplies in the United States.** While their action is not binding, prudence dictates that no form of treatment should be used that will result in raising the con centration of the substances listed above the value cited. Since virtually all of the permissible chemicals used for scale, slime, and corrosion control have deleterious physio logical effects if takeD internally in relatively large doses, they should always be carefully proportioned. To insure this, the Detroit ordinance stipulates that the chemical feeding device must have the following major characteristics: "1. There shall be a visible means of checking the quantity of material being applied by the feeding device. 2. A water metering device, sealed to prevent tampering, shall be installed to measure the flow of water being treated. 3. The device shall be constructed so that in the event of back-flow or vacuums, the maximum amount of material that may be possibly back-siphoned from the device or any of its attachments or parts shall not exceed one fluid ounce. 4. Should there be a failure of the water metering device or the water supply, die feeding device shall automatically cease operating." REFERWCES `Committee D-19: Annual Report (American Society for Testing Materials, 1947). . *H. H. Uhlig (ed.): Corrosion Handbook (John Wiley & Sons, New York, p. 27). Discussion (Corrosion and Material Protection, May 1945, P- 2). *W. C. Schroeder: Round-table discussion on organizing the classification of industrial waters (American Society for Testing Materials Proceedings, Vol. 44, 1944, p. 1057). * W. D. Collins: Typical water analyses for classification with reference to industrial use (American Society for Testing Ma terials Proceedings, Vol. 44, 1944, p. 1057). * ASTM Standard D-696-41 (American Society for Testing Materials). * E. W. Guernsey: Discussion on preventing solution of COs in condensates (ASHVE Transactions, Vol. 51,1945, p. 69). * L. F. Collins: Studies of the mechanism of solution of COs in condensates formed in steam heating systems of buildings (ASHVE Transactions, Vol. 51,1945, p. 39). * W. F. Langelier: The analytical control of anti-corrosion water treatment (American Water Works Association Journal, Vol. 28, 1936, p. 1500). , "G. B. Hatch and Owen'Rice: Surface-active properties f hexaxnetaphosphate (Industrial and Engineering Chemistry Vol. 31, 1939, p. 51). " G. B. Hatch and Owen Rice: Threshold treatment of water systems (Industrial and Engineering Chemistry, Vol. 37, 1954, p. 710). "Betz Handbook of Industrial Water Conditioning (W. H. A L. D. Bet* Co., 4th ed.). "S. Sussman: Cooling water problems in the New York metropolitan area (Industrial and Engineering Chemistry, August 1952, p. 1740). . "J. A. Holmes: Slime control in cooling equipment with phenol derivatives (Annual Water Conference Proceedings, ` Engineers' Society of Western Pennsylvania, 1944, p. 61). "H. G. Reddick and S. E. Lindcrman: Tuberculation of mains as affected by bacteria (Neu> England Water Works As sociation Journal, Vol. 46, -No. 42). "R. F. Hadley: Microbiological anaerobic corrosion of steel pipe lines (The Oil and Gas Journal, September 1939). "S. T. Powell: Cold water vacuum deaeration (Water Con ference Proceedings, Engineers1 Society of Western Pennsyl vania, 1945, p. 51). . "G. B. Hatch and Owen Rice: Corrosion control with threshold treatment (Industrial and Engineering Chemistry, Vol. 32, 1940, p. 1572). . "J. H. Wilson and E. C. Groesback: Testa of corrosion in hibitors for water treatment in air conditioning equipment (National Bureau of Standards Journal of Research, Vol. 24, 1940, p.665). ' ... *C. M. Sterne: The control of corrosion in air-conditioning equipment by chemical methods (American Society for Testing Materials Proceedings, Vol. 38, 1935, Part 2, p. 261). D Sidney Sussman and J. B. Pullman - Corrosion in closed recirculating water systems (Heating and Ventilating, October 1953, p. 77). -F. N. Speller: Corrosion--Cause* and Prevention (Mc Graw-Hill Book Co., New York, 1951, pp. 805, 905, 910, 912). "L. F. Collins: Engineering problems of water treatment (Power Plant Engineering, July 1946, pp. 78, 120). ** Corrosion and its Prevention (Air-Conditioning and Re frigeration Institute, Washington, D. C., 1958). " See p. 470 of Reference 19. **Studies in The Detroit Edison Co. (Unpublished). " D. S. McKinney, J. J- McGovern, C. W. Young, and L. F. Collins: Preventing the solution of CO* in condensates by vent ing of the vapor space of steam heating equipment (ASHVE Transactions, Vol. 51,1945, p. 53). " L. F. Collins and E. L. Henderson: Corrosion in steam heating systems (Heating, Piping and Air Conditioning, Oc tober 1939, p. 620). 746 CHAPTER 55 1959 Guide .1 U. S. Patent 1,395,730. "U. 8. Patent 2/153,024. (National Bureau of Standards Journal of Research, Vol. 33 1944, p.145). ' "U. S. Patent 1,903,287. " A. A. Berk: Treating steam chemically to reduce return line corrosion (Industry and Power, November 1947, p. 79). . "L. P. Sudrabin: Cathodic protection of steel equipment submerged in water (Water.Conference Proceedings, Engineers' Society of Western Pennsylvania, 1944). "Testa in The Detroit Edison Co. (Unpublished). **J. J. McNeil: Rubber linings and rvt.mga (Corrosion and Material Protection, March-April 1947). *D. W. Haering: A discussion. (See p. 66 of Reference 14.) T. S. Carswell and H. L. Morrill: Cydohexylamine and dicyclohexylainine (Industrial and Engineering Chemistry Vol "L V. Schaefer: Protection of steel bins from corrosion 29,1937,0.1247). v' (Power Plant Engineering, Vol. 26, 1922, p. 632). aDrinking Water Standards, etc. (Public Health Reports, "E. R. Walters: Some Notes on Corrosion of Cast-Iron Sectional Boilers (The Institution of Heating and Ventilating Engineers, preprint 1944). Vol. 58. No. 3. Reprint No. 2440, January 15, 1943). R. M. Palmer: Discussion (Heating and Ventilating. Oc tober 1953), ' Seep. 67 of Reference 2. "K. H. Logan and M. Romanoff: Soil corrosion studies, 1941 " Official Plumbing Code of the City of Detroit, Article V. Private Communication from H. S. Jordan, AWWA. CHAPTER 56 WATER SERVICES Sizing Cold Water Supply Piping, Procedure for Sizing Cold Water Systems, Cooling Wafer Piping, Estimating Hearing . load and Storage Capacity, Methods of Heating Water, Direct-Fired, Electric, and Indirect Water Heaters, Computing Heat Transfer Surface, Hot Water Supply Piping, Control of Service Water Temperature, Safety Devices, Sohr Water Heaters, Domestic Hof Water by Heat Pump PROPER design of the water distributing system in a types of fixtures, and the average pressure necessary to give building is necessary in order that the various fixtures this rate of flow. The pressure necessarily varies with fixture may function properly. The amount of either hot or colddesign, a much greater pressure being necessary with some water used in any building is variable, depending on the type fixtures to give the same rate of fiow as in others. In general, of structure, usage, occupancy, and time of day. It is neces- the lower the quality of the faueet the greater will be the sary to provide piping, water heating, and storage facilities pressure required. . . of sufficient capacity to meet the peak demand without In estimating the load, the rate of flow is frequently com wasteful excess in either piping or equivalent cost. puted in fixture units. One fixture unit is equivalent to 7.5 SIZING COLD WATER SUPPLY PIPING gal per min. Table 2 gives the demand weights in terms of fixture units for different plumbing fixtures under several One of the important items that must be determined before any part of the water-piping system can be sized, is the probable rate of fiow in any particular reach of piping. The rate of flow in the service line, risers, and main branches, however, will rarely be equal to the sum of the rates of flow of all connected fixtures. In fact, the probability that every fixture in a large group will be in use at the same time is so remote that it would be very poor engineering practice to design the piping to take care of such simultaneous flow. The demand load in building water supply systems cannot be determined exactly and is not readily standardized. The two main problems to be considered are: (1) the satisfactory^ supply of water for a given fixture, and (2) the number of fixtures which may be assumed to be in use at the same time. The minimum flow that will be satisfactory to the con sumer depends greatly on the consumer, his standard of liv ing, his professional needs, size of family, garden require ments, and similar factors. Depending on these factors, the per capita water consumption for domestic use usually varies conditions of service, and Fig. I gives the estimated demand in gallons per minute corresponding to any total number of fixture units. Fig. 2 shows an enlargement of Fig. 1 for a range up to 250 fixture units. The estimated demand load for fixtures used intermittently on any supply pipe will be obtained by multiplying the num ber of each kind of fixture supplied through that pipe by its weight from Table 2, adding the products, and then referring to the appropriate curve of Figs. 1 or 2 to find the demand corresponding to the total fixture units. In using this method it should be noted that the demand for fixture or supply out lets other than those listed in the table of fixture units is not yet included in the estimate. The demands for outlets (such as hose connections, air-conditioning apparatus, etc.) which are likely to impose continuous demand during times of heavy use of the weighted fixtures, should be estimated sepa rately and added to the demand for fixtures used intermit tently, in order to estimate the total demand. So far, the information presented makes possible the de- between 20 and 80 gal per day. Experience indicates that the type of dwelling also has considerable influence on the water consumption. . - In apartment houses the per capita daily water consump Table 1.... Proper Flow and Pressure Required During Flow for Different Fixtures tion is generally higher than in single-family houses. This is due to the use of a central metering system which is not con Rxfcrre Row Prerwre* Row gpa ducive to the saving of water, and to the long hot water lines which cause high heat losses and an increase in the wasting of the cooled water. In designing water supply systems for apartment houses, a daily per capita water consumption of 50 gal may be considered a safe design figure. Ordinary basin faucet............................... Self-closing basin faucet............. ............ Sink faucet--% in...................................... Sink faucet--^ in...................................... 8 12 10 5 3.0 2.5 4.5 4.5 Although a considerable number of housing projects have Bathtub faucet........................................... 5 6.0 been developed throughout the United States, conclusive Laundry tub cock--Vi in....................... 5 5.0 water consumption data have not yet been gathered. Never theless, it seems that the daily per capita water consumption Ball-cock for closet................................... 15 3.0 in housing projects falls in between the consumption in apart ment houses and that in single dwellings at the same geo graphical location. In general, a daily per capita water con Flush valve for closet............................... Flush valve for urinal.............................. Garden hose, 50 ft, and sill cock........... 10-20 15 30 15-40* 15.0 5.0 sumption of 40 gal can be used as a safe design figure for housing projects. Table 1 gives the rate of flow desirable for many common * Flow prawn b the preeeore in the pipe et the entrance to the particular fixture considered. b Wide rmn<e due to variation in deaicn end type et flush-valve doaeta. . 747 748 :HAPTER 56 1959 Guide termination of the design rate of flow in any particular sec tion of piping. The next general step is to determine the size of piping. As water flows through a pipe, the pressure continually de creases along the pipe, due to loss of energy from friction. The problem is then one of ascertaining the minimum pres sure in the street main, and the minimum pressure required for the operation of the topmost fixture. (A pressure of 15 psi is'ample for flush valves, but reference should be made to the manufacturers' requirements. A minimum of 8 psi should be allowed for other fixtures.) The pressure differ ential thus obtained will be available for overcoming pressure losses in the distributing system, and in overcoming the dif ference in elevation between the water main and the highest fixture. The pressure loss, in pounds per square inch, caused by the difference in elevation between the street main and the high est fixture, may be obtained by multiplying the difference in etevation in feet by the conversion factor 0.43. When water flows through a pipe, friction occurs as the re sult of the sliding of water particles past one another. If the pipe wall is rough, the roughness projections cause addi tional friction, owing to the development of increased turbu lence in the flowing water. As the water flows along a uni form pipe, the pressure decreases as a result of a dissipation of energy arising from the internal friction set up by viscosity of the water. This loss in energy is shown by the loss of pressure. The pressure loss is proportional to the length of straight uniform pipes, and varies greatly with flow velocity, pipe diameter, roughness of pipe, and water temperature. Table 2....Demand Weights of Fixtures in fixture Units* Fixture or Group* . Occupancy Type of Supply Control Weight m Fixture Uwh* Kitchen sink................... Hotel or restaur&nt... Faucet.......... pMW.tQ ` 4 for closet.. for closet.. Combination fixture.... Private....... Faucet.......... 8 6 2 3 3 * For supply outlets likely to impose eoatinaou* demands, estimate continu ous supply Mpemtely end edd to total demssd (or fixture*. b For fixture* not listed, weights mty be assumed by compering the fixture to listed one using water in similar quantities end et similar rates. The given weights are (or total demand. For fixtures with both hot and edd water supplies, the weights (or maximum separate demands may be taken a* 94 the listed demand (or the supply. No. J for system predominantly for flush valves. No. 2 for system predominancy for flush fonts. fig. \.... Estimate Curves for Demand Load On the basis of inside surface conditions, pipes may be classified as smooth, fairly rough, and rough, as follows: Smooth. The pipe surface shows no perceptible roughness. Pipes made of copper, brass, or lead may usually be classified as smooth. Fairly Rough. All ordinary pipes, such as wrought iron, gal vanized iron, steel, and cast iron, after a few years of usage, may be called fairly rough. Rough. Pipes that have deteriorated fairly rapidly for some 10 or 15 years alter being laid, are classified as rough. Figs. 3, 4, and 5 give the pipe frictiou losses corresponding to these three types of pipes for various nominal diameters for a water temperature of 50 F.1 Example 1 will illustrate the use of the charts. Example 1: A 2Vi-in. fairly rough pipe supplies 100 gpm of water. Find the friction loss in head if the pipe length is 200 ft. Solution: Enter Fig. 4 at 100 gpm, and move along this line until it intersects the 214-in. diameter line. From this intersec tion point, move vertically down and read 4.5 psi friction loss per 100 ft of pipe length. Then the total friction loss will be 2 X 45 = 9 psi. The pressure losses in the distributing system will consist of the pressure losses in the piping itself, plus the pressure losses in the pipe fittings, valves, and the water meter, if any. Approximate design pressure losses for disc-type meters for various rates of flow are given in Fig. 6. Flow limits for disctype meters, which may be regarded as the limits of recom mended ranges in capacities, are given in Table 3. Manufac turers should be consulted for data on exact pressure losses and capacities since these vary for meters of different internal design. fig. 2.... Section of fig. 1 on Enlarged Scale .2 Wafer Services FRICTION LOSS IN HEAD IN LBS. PER SQ. IN. PER IOO FT. LENGTH 749 / Fig. 2.... Flow Chart for Copper Tube1 Fig. 7 shows the variation of pressure loss with rate of flow for various types of faucets and cocks, based on experimental data obtained at the State University of Iowa. The loss of pressure through any fitting or valve can be expressed in pounds per square inch for any given rate of flow. Experience has shown, however, that the simplest method of expressing losses in fittings and valves is to use the concept of an equivalent length of straight pipe. Thus it has 750 CHAPTER 56 1959. Guide FRICTION LOSS IN HEAD IN LBS. PER SQ. IN. PER IOO FT LENGTH Water Services FRICTION LOSS IN HEAD IN LBS. PER SQ. IN. PER 100 FT. LENGTH 751 Fig. 4.... Flow Chart for Fairly Rough Pipe1 been found, for example, that a 1-tn., 90-deg elbow introduces a loss equivalent to 22 ft of straight 1-in. pipe. Therefore, for each 1-in., 90-deg elbow, 22 ft of 1-in. pipe axe added to the total length of 1-in. pipe. Estimated pressure losses for pipe fittings and valves in terms of equivalent pipe length are shown in Table 4. Table 5 lists the equivalent lengths for various special types of apparatus and fittings. The loss in water meters varies considerably with the design even in meters of the same nominal size. The values given in Table 5 are ample for the well-known meters now on the market. The water demand for hose bibbs or other large demand fig. 5____Flow Chart for Rough Pipe1 fixtures taken off the building main is frequently the cause of inadequate water supply to the upper floor of a building. This condition may be prevented by sizing the distribution system so that the pressure drops from the street main to all fixtures are the same. It is good practice to maintain the building main of ample size (not less than 1 in. where possi ble) until all branches to hose bibbs have been connected. Where the street main pressure is excessive and a pressure reducing valve is used to prevent water hammer or excessive pressure at the fixtures, it is frequently desirable to connect hose bibbs ahead of the reducing valve. . The principles involved in sizing either up-feed or down- 752 CHAPTER 56 1959 Guide Table 3.... Performance Requirements of Water Meters* Site, In. Normal Test-Flow - Iosifs, Gpm Minimum Test-Flow, Gpm ($ manufacturer'* date far exact valve for meter used) Rg. 6.... Pressure Losses in Water Meters feed systems are the same. The principal difference in pro cedure is that in the down-feed system, the difference in elevation between the house tank and the fixtures provides the pressure required to overcome pipe friction. Procedure for Sizing Cold Water Systems The recommended procedure for sizing piping systems is outlined in following paragraphs 1 to 6, inclusive. 1. Draw a sketch of the main lines, risers, and branches, and indicate the fixtures to be served. Indicate the rate of Sow of each fixture. 2. Using Table 2, compute the demand weights of the fixtures in fixture units. - 3. Determine the total demand in fixture units and, using Fig.! or Fig. 2, find the expected demand in gallons per minute. H.................................... H.................................... l........................................... IK....................................... 2........................................... 3.......................................... 6....................................... 1 to 2 to 3 to 5 to 20 34 53 100 8 to 160 16 to 315 28 to 500 48 to 1,000 . K K K ik 2 4 7 12 * American Water Works Association Standards: . Rcgmtntioa. The registntioD on the meter dial ehnU indicate the quantity recorded to be not leas than 98 percent nor more than 103 percent at the water actually passed through She meter while it a being tested at rates cd Sow within tt. specified limits nmuml test Sow limits; There shall be not lees timn 90 percent of the aetual Sow recorded when a test b made at the rate of flow get forth under minimum test flow. - 4. Determine the equivalent length of pipe in the main lines, risers, and branches. Since the sizes of the pipes are not known, the exact equivalent length for various fittings, etc., cannot be made. Add the equivalent lengths, starting at the street main . anH proceeding along the service line, the main line in the building, and up the riser to the top fixture of the group served. 5. Determine the average minimum pressure in' the street main and the minimum pressure required for the operation of the topmost fixture. This latter pressure should be 8 to 15 pri. 6. Calculate, by means of Equation i, the approximate de sign value of the average pressure drop per 100 ft of pipe in the equivalent length determined in paragraph 4. p - IP - 0.43H - 101 i52 (1) where . p -- average pressure loss per 100 ft of equivalent length of pipe, psi. P = pressure in street main, psig. H =* height of highest fixture, above street main, feet. L = equivalent length determined in paragraph 4, feet. If the system is of the down-feed supply from a gravity tank, the height of water in the tank, converted to pounos per square B. laundry compression faucet. C-l. ^-in. compcwwfcn safe faucet (Mfr. I). C-2. %-tn. compression sink faucet (Mfr. 2). 0. Combination compression bathtub faucets (both open). E, Combination compression smfc faucet. F. Basin faucet. C. Spring self-dosing faucet. H. Stow toff-dosing faucet. (Dashed fines indicate recommended extrapolation! ' . Rg. 7.... Variation of Pressure Loss with Rate of Row for Various Faucets and Cocks - Table 4.... Allowance in Equivalent Length of Pipe for Friction Loss in Valves and Threaded Rttings Equivalent Length of Pipe for Various Fittings Oiainefer of Fitting, in. 90-Dog Stand ard Bl, Ft 45-Dog Stand ard Bl, Ft 90-Dog Side Too Ft Coupling or Straight Run of Too, Ft Goto Valve. Ft Globe Anglo Valve, Valve, Ft Ft X........ 1 0.6 1.5 K........ 2 1.2 3 X........ 2.5 1.5 4 l............ 3 1.8 5 0.3 0.6 0.8 0.9 0.2 8 4 0.4 15 8 0`. 5 20 12 0.6 25 15 IX........ 4 2.4 6 1.2 0.8 35 18 ik........ 2............ 2H........ 3............ 3K........ 5 7 8 10 12 37 4 10 5 12 6 15 7 18 1.5 1.0 45 22 2 1.3 55 28 2.5 1.6 65 34 3 2 80 40 3.6 2.4 100 50 4............ 14 8 21 5............ 17 10 25 6............ 20 12 30 4.0 2.7 125 55 5 3.3 140 70 6 4 165 80 Wafer Services 753 Table S....Equivalent Lengths of Iron Pipe to Give Some Loss os Special Rttings and Apparatus Fitting Apparatus Nominal Diameter of PipeInches MH iK 30-gal Vertical hot water tank, K*- pipe............................................ 4 17 56 30-gal Horizontal hot water tank, H*in- pipe......................................... 1.2 5 16 -- Water meters (No valves included) % in. with H~iD- connections----- 6.7 28 90 -- % in. with %-in. connections----- 4.8 20 64 -- % in. with %-in. connections----- 3.4 14 45 -- 1 in. with 1-in. connections.......... -- 9 30 115 1% in. with 1-in. connections.... -- 4.4 14 54 Water softener....................................... -- 50-200 -- _ Table 7.... Pipe Sizes for Cooling Towers* Rated Tons of Refrig. Cooling Water Gpm Pipe Sizes (Nominal (nebos) Inlot to Tower Outlet from Tower 3 to 5 . 7 to 15 20 25 35 50 75 100 150 200 250 10 to 18 20 to 45 65 86 215 170 225 300 450 GOO 750 IK .2 2K 2K 3 3 5 5 5 6 8 IK 2 3' 4 4 4 6 6 8 8 8 inch by multiplying by 0.43, replaces the street main pressure, and the term 0.43 H in Equation 1 is added instead of sub The sizing of the branches of the building main, the risen, tracted in calculating the term p. In this case, H will be the and fixture branches follows the principles outlined. For exam vertical distance of die fixture below the bottom of the tank. _ ple, assume that one of the branches of the building-main car 7. From the expected rate of flow, determined as in paragraph - 3, and the value of p, calculated as in paragraph 6, choose the sizes of pipe from Figs. 3, 4, or 5. Example f- Assume a minimum street main pressure, of 55 prig; a height of topmost fixture above street main of 50 ft; ries the cold water supply for 3 water closets, 2 bathtubs, and 3 lavatories. Using the permissible pressure loss of 8 pri per 100 ft, the size of branch determined from Table 2 and Figs. 1 and 4 is found to be 1 Vi in. Items entering the computation of pipe size are given in Table 6. a developed pipe length from water main to highest fixture of 100 ft; a total load on the system of 50 fixture units; and that COOLING WATER PIPING the water closets are flush-valve operated. Find the required size of supply main. Water is very frequently used in refrigeration systems, Solution: From Fig. 2 the estimated peak demand is found cooling towers, and other similar installations. In designing to be 51 gpra. From Table 3 it is evident that several sizes of the piping system of such installations, the principles of hy meters would adequately measure this flow. For a trial computa tion choose the lyi-in. meter. From Fig. 6 the pressure drop through a lVi-in. disc-type meter for a flow of 51 gpm is found draulics, as already outlined, are employed. Nevertheless, . there are several practical items having particular applica to be 8.5 psi. tion to cooling installations which are outlined in the fol Then the pressure drop available for overcoming friction in pipes and fittings is55--(15 + 50X 0.43 + 6.5) -- 12 pri. lowing paragraphs. It is important that the designer be familiar with them. At thia point it is necessary to make some estimate of the equivalent pipe length of the fittings on the direct line from the street mam to the highest fixture. The exact equivalent length of the various fittings cannot now be determined since In choosing pipe material, the problem of corrosion should be kept in mind to prevent failure of the system. If the water is not severely corrosive, wrought-iron or steel piping may be the pipe sizes of the building main, riser, and branch leading to used; otherwise, galvanized-eteel piping may be preferred. the highest fixture are not known as yet, but a first approxima tion is necessary in order to make a tentative selection of pipe sizes. If the computed pipe sizes differ from those used in deter mining the equivalent length of' pipe fittings, a recalculation If sea water is used as the circulating medium, it is advisable to use alloys such as admiralty metal in pipe and tubing. In refrigeration condensers where water is the cooling medium, will be necessary, uring the computed pipe axes for the fittings. iron pipe is commonly employed. For the purposes of this example assume that the total equiva In regard to assembly, cast-iron flanges or welded joints lent length of the pipe fittings is 50 ft. are to be preferred to screwed joints wherever possible. Then the permimible pressure loss per TOO ft of equivalent pipe is 12 X 100/(100 + 50) = 8 pri. - Valves used in circulating systems may be of the globe, gate, or angle types. If water is the circulating medium, Assuming that the corrosive and caking properties of the water are such that Fig. 4 for fairly rough pipe is applicable, a . brass valves are usually used. However, if the circulating 2-in. building main will be adequate. medium is an electrolyte, such as brine, then it is preferable Table 6.... Computation of Branch Size m Example 2 to use valves made of the same material as the piping itself. The friction loss in the piping may be determined from No. and Kind Fixture Units (From Table 2 and Nolo c) Demand Fig. 2) Gpm Pipe Size (From fig. 41 In. Fig. 4 for fairly rough pipe. If the coolant is brine, a correc tion for the proper density must be made. Experience indi cates that in sizing piping for cooling systems, a pressure drop of the order of 2 to 3 psi per 100 ft of pipe length, and a fluid velocity of 3 to 8 fps, yield most economical results. 3 flush valves 3x6 - 18 H (2 x 2) - 3 X (3 x 1) - 2.25 In the case of cooling towers, the amount of circulating water is about 3 gpm per ton of refrigeration, when based on a design wet-bulb temperature of about 76 F. Table 7 gives pipe sizes frequently used for various sizes of cooling towers, Total 23.25 38 IK assuming a hot water temperature of 95 F and a cold water temperature of 85F* ' 754 CHAPTER 56 1959 Guide Table 8____Maximum Daily (24-Hr) Requirements for Hot Water in Gallons No. of Room* 2345 60 2 70 --_ 3 80 -- -- -- -- 4 90 120 -- -- -- 5 100 140 -- -- -- 6 120 160 200 -- -- 7 140 180 220 -- -- Apartment* 8 160 200 240 250 -- iiihI 9 ISO 220 260 275 -- Private Homes 10 200 240 280 300 -- -- 260 12 __ 280 325 380 450 13 -- 300 350 420 500 14 -- -- 375 460 550 15 -- -- 400 500 600 16 __ __ -- 540 650 17 __ __ -- 580 700 18 -- -- -- 620 750 19 -- -- -- -- 800 20 -- -- -- -- 850 Hotels Room with basin. Room with bath-- transient. . . Room with bath-- resident....... 2 Rooms with bath....... 3 Rooms with bath....... Public shower___ Public basins.. . Slop sink. .. 10 .. 50 .. 60 .. 80 .. 100 .. 200 .. 150 .. 30 Office Balding! White-collar worker (per person). . ... 2.0 Other workers (per person).............. ... 4.0 Cleaning per 10,000 sq ft.................. ... 30.0 Hospitals Per bed.................................................... . 80-100 ESTIMATING HEATING LOAD AND STORAGE CAPACITY The maximum daily and the maximum hourly hot water demand form the haris for the selection of the beater and the Storage tank In general, two-thirds of the total daily water consump tion is hot water. For residential dwellings, a design value of about 20 to 30 gal per (person) (day) may be assumed, but it should be remembered that the hot water used will depend on the number of rooms and the number of bathrooms in any house or apartment. Table 8 gives estimates of the maxi mum hot water requirements in 24 hr in various types of buildingB. In estimating the size of hot water storage tank required, and the heating capacity to be provided, either from the . boiler or from an independent domestic hot water heater, it is necessary to know the total quantity of water to be heated per day, and the maximum amount which will be used in any one hour, as well as the duration of the peak load. In cases where the requirements for hot water are reason ably uniform, as in residences, apartment buildings, hotels, and the like, smaller storage capacity is required than in the case of factories, schools, and office buildings, where practi cally the entire day's usage of hot water occurs during a very short period. Correspondingly, the heating capacity must be proportionately greater with uniform usage of hot water than with intermittent usage, where there may be several hours between peak demands during which the water in the Table 9.... Estimated Hot Water Demand Characteristics for Various Types of Buildings Type of Budding Hof Wafer Per Mox. Hourly Demand in Refation fo Day** Use Deration of Peak Load Storage Capacity in gelation to Day'* Use Capacity in Relation fo Day'* Use Residences, apartments, hotels, etc. 40 gal per day4 IP 4 1/5 1/7 Office buildings 2 gal per day4 1/5 2 1/5 1/6 Factory buildings 5 gal per day4 1/3 1 2/5 1/8 Restaurants 1/10 1/10 Restaurants 3 meals/day 1/10 8 1/5 1/10 Restaurants 1 meal/day 1/5 2 2/5 1/6 At 140 F. storage tank can be brought up to temperature. As a gen eral rule, it is desirable to have a large storage capacity in order that the heating capacity, and consequently the size of the heater, or the load on the beating boiler, may be as small as possible. ' ' In estimating the hot water which can be drawn from a storage tank, it should be borne in mind that only about 75 percent of the volume of the tank is available, since, by the time this quantity been drawn off, the incoming cold water has cooled the remainder down to a point where it can no longer be considered hot water. . Where steam from the heating boiler is used to heat do mestic hot water, the computed load on the boiler should be increased by 4 sq ft EDR (equivalent direct radiation) for every gallon of water per hour heated through a 100 deg rise. The actual requirement is (100 X 8.33)/240 = 3-48 sq ft per gal heated 100 deg. The value of 4 allows for transmission losses. There are two methods in common use for estimating the hot water requirements of a building: (1) by the number of people, and (2) by the number of plumbing fixtures in stalled. Where the number of people to be served can be rea sonably estimated, the data in Table 9 may be used. Example S: Determine the heater size and storage tank capac ity for a residence housing five people. . Solution: From Table 9, a residence housing five people would have a daily requirement of 5 X 40 = 200 gal per day, and a maximum hourly demand of 200 X 1/7 ~ 28.fi gal. The heater should have a storage capacity of 200 X 1/5 = 40 gal, and a heating capacity of 200 X 1/7 -- 285 gal per hi. The conditions given in Example S may be cited as aver age. It is possible to vary the storage and hearing capacity by increasing and decreasing one over the other. Such a condi tion is illustrated in Example 4- Example 4- Determine the required heater capacity for an apartment housing 200 people, if the storage tank has a capac ity of 1000 gal. What heater capacity will be required if the storage tank is changed to 2500 gal Capacity? Solution: Assume an apartment house housing 200 people. From the data in Table 9: Daily requirements -- 200 X 40 = 8000 gal. Maximum hours demand = 8000 X 1/7 -- 1140 gal. Wafer Services 755 Duration of peak load -- 4 hr. Water required for 4-hr peak = 4 X 1140 = 4560. ` If a 1000-gal storage tank is used, hot water available from the tank -- 1000 X 0.75 = 750. Water to be heated in 4 hr -- 4560 -- 750 ~ 3710 gal. Heating capacity per hour -- 3710/4 -- 930 gal. If instead of a 1000-gal tank, a 2500-gal t-nlr had been in stalled, the required heating capacity per hour would be [4560 -- (2500 X 0.75)]/4 = 671 gal. Table 10 may be used to determine the size of water heat ing equipment from the number of fixtures. To obtain the probable maximum demand, multiply the total quantity for the fixtures by the demand factor in line 11. The heater or coil should have a water heating capacity equal to thin prob able maximum demand. The storage tank should have a capacity equal to the probable maximum demand multiplied by the storage capacity factor in line 12. Example 5 will illustrate the procedure. Example 5: Determination of heater and storage for an apartment building from number of fixtures. size 60 lavatories........................................... X 2 -- 120 gal per hr 30 bathtubs............................................ X 20 TM 600 gal per hr 30 showers.............................................. X 75 = 2250 gal per hr 60 kitchen sinks.................................... X 10 - 600 gal per br 15 laundry tubs........................ '.......... X 20 = 300 gal per hr Possible maximum demand.............. Probable maximum demand............. Heater or coil capacity...................... Storage tank capacity........................ = 3870 gal per hr -- 3870 X 0.30 = 1161 gal per hr -- 1161 gal per hr = 1161 X 1.25 - K50 gal Although, in private dwellings a water temperature of 140 F is reasonable for dishwashing, in public places sanitation regulations call for 180 F water. Most of the dishwashing, machines now available on the market require 180 F water. The amount of .180 F water needed in restaurants per day may be determined according to the method outlined by the American Gas Association* in the following paragraphs: 1. Multiply the number of meals per day by the number of dishes per meal (6 for low-price restaurants, 8 for medium-price restaurants, and 10 for high-price restaurants) to determine the total number of dishes per day. 2. Divide the total number of dishes per day, as determined by method in paragraph 1, by the average number of dishes per rack to find the number of racks per day. 3. Multiply the number of racks per day by the ga-llnnn of 180 F water (using 15 for single tank machines ana 0.75 for two tank machines). This product will give the gallons of 180 F water per day for rinse sprays. 4. Multiply the number of meal periods per day (one, two, or three) by the dishwashing tank capacity in gallons, giving the gallons of 180 F water per day necessary to ml the tanks. 5. Add values from paragraphs 3 and 4 to obtain the total number of gallons of 180 F water required per day. For purposes other than dishwashing, a considerable amount of 140 F water is also used. To find the daily 140 F water requirement in a restaurant, multiply the total num ber of meals served per day by the gallons of 140 F water per meal. Low priced restaurants on the average utilize 0.9 gal of 140 F water per meal, while medium- and high-price restaurants use 12 and 1.5 gal per meal, respectively.* METHODS OF HEATING WATER Hot water may be heated either by the direct combustion of fuel, by an intermediate carrier such as steam or hot water, or by electrically heated surfaces. The simplest method is to have the fire on one ride of a metal barrier and water on the other. In such a method, if the surfaces for transferring heat are small, and if the water carries, a heavy proportion of precipitable salts, the water passages may soon become clogged with resultant cracking or burning of the surface. A familiar example of such trouble is the water back in the kitchen stove, or the pipe coil inserted into the firebox of a warm air furnace or small boiler. The critical water tem- Toble 10.... Hot Water Demand per Fixtures for Various Types of Buildings Gattatu of water par hoar par filter*, calculated at a final temperature of 140 f Apartment House Club Gym- Hetpcfaf Hofei ' Industrial Phot Office Building Private Residence School XM.CA. 1. Basins, private lavatory.... 2 22 2. Basina, public lavatory......... 4 68 3. Bathtubs.................. . 20 20 30 4. Dishwashers................................ 15 50-150 5. Foot basins... . . 3 3 12 6. Kitchen sink.... . 10 20 7. Laundry, stationary tubs... 8. Pantry sink................................... 20 5 28 10 9. Showers....................... . 75 150 225 10. Slop sink.............. . 20 20 11. Demand factor........................ 0.30 0.30 0.40 12. Storage capacity factor4.... 1.25 0.90 1.00 4 Buio of Mange tank capacity to probable maximum per hour. 2 6 20 50-150 3 20 28 10 75 20 0.25 0.60 2 8 20 50-200 3 20 28 10 75 30 0.25 0.80 2 12 30 20-100 12 20 225 20 0.40 1.00 2 6 15 0.30 2.00 2 20 15 3 10 20 5 75 15 0.30 0.70 22 15 8 30 20-100 20-100 3 12 ib 20 28 10 10 225 225 20 20 0.40 1.00 0.40 1.00 756 CHAPTER 56 1959 Guide perature at which the lime, magnesia, etc., collect on hot sur faces, varies with the character and proportions of the solids, but generally such deposits are not a serious trouble below HOF. Direct-Fired Water Heaters Coal-burning, direct-fired water heaters may be constructed of cored cast-iron sections, or of steel. In some cases the ex ternal appearance of the cast-iron sections is the same as in hpAting boilers, but internally the cores are changed to en able the sections to withstand the city water pressure. In small capacity water heaters, efficiency is not considered so important as low first cost and ability to maintain a fire at a low rate of combustion, and consequently, such heaters are generally built with a dry section or firebrick lining at the base of the firepot to prevent too much chilling of the fuel. While mud and scale will eventually clog the waterways of any direct-fired heater, increased life may be obtained by providing a three-way cock in the return line between the heater and the bottom of the storage tank, so that water can be blown through the heater or the tank separately, at full line pressure, to clean out loose sediment. Cleanout openings in the bottom of the heater are advantageous, if used by op erators of water heaters for periodic cleaning out of sedi ment. Oil-burning, direct-fired water heaters usually are of steel, and operate with higher flame temperature and better effi ciency than commensurate sized coal-burning heaters. As they have the same tendency as coal boilers to accumulate lime deposits, the water passages should be large in cross section and accessible for periodic cleaning. Gas-burning, direct-fired water beaters may be of the instantaneous or storage type. Instantaneous heaters are generally constructed of spiral water tubes of copper, around . which the products of combustion circulate upward from high capacity burners. Storage-type heaters may include in one unit an insulated storage tank, a combustion chamber, flues, burner equipment, and controls, or may consist of a separate storage tank and external direct-fired water heater, which may be a so-called side-arm heater for small capacity, or a gas-fired boiler for larger capacity. Gas boilers used for direct hot water supply must be able to withstand the city water operating pressure. While direct-fired gas heaters are used generally for residences and small installations of 100 gal storage capacity or less, indirect heaters are recommended for larger installations. Chimney connections for all direct-fired, fuel-burning wa ter heaters are an important consideration. Refer to Chapter 36. - Electric Water Heaters Table 11.... Standard Rated Capacities of Electric Water Heaters Tank Six* GaOon* Nominal Rang* Bated loput, Wall* Two-Unit Hooter Primary Secondary Single-Unit Heater 30 40 52 66 80 no 120 140- 30 to 35 35 to 45 45 to 55 55 to 70 70 to 90 90 to 115 115 to 135 135 to 175 600 750 1000. 1250 1500 1000 1250 1500 2000 2500 2000 2500 3000 3000 4000 4000 1500 2000 2500 3000 4000 Instantaneous heaters are used in special cases only, be cause of the high electric power input required, for example, 15 kw to deliver 1 gpm with 100 deg temperature rise. Capacities of household automatic storage-type water heaters, as partially standardized within the electrical in- dustry, range from 30 to 140 gal nominal tank capacity with input 1600 to 7000 watts. Wattage input ratings of two-unit heaters are based on approximately 30 watts per gallon of tank capacity for the secondary unit and 20 watts for the primary unit. Single-unit heaters have tank sizes up to 80 gal with an input of 4000 watts, the ratings being based on 50 watts per gallon. The schedule of heater capacities shown in ASA Standard C72.1-1949 is reproduced in Table 11. ' The wattages listed in Table 11 are minimum recommended values for continuous service. Some departure from the standardized watts-per-gallon ratios is to be expected, as experience indicates that increased hot water use with auto matic laundry machines and dishwashers may call for larger heating units than have heretofore been found desirable. With off-peak operation the watts-per-gallon ratio likewise must be raised. Rated voltage for water heaters is 240 volts, with a range 220 volts minimum to 248 volts maximum, but specified test performance is required to be met only at the 236 volts taken as normal design voltage. Thermostats controlling the heating units are normally set for 150 F, with upper limit of adjustment range of 170 to 180 F. . Heating units are of three general types, all of which give approximately the same service efficiency if selected to suit the operating conditions, as follows: Electric water heaters for hot water service in residences and commercial buildings are predominantly of the automatic storage type. These generally have a cylindrical tank mounted vertically, with a primary electric heating element or re sistor near the bottom and a secondary unit located within the upper one-quarter of the tank. Water heaters of tingle heating-unit type have an element only at the bottom. The first cost of automatic electric heaters is somewhat higher than that of fuel-fired types, owing to the need for larger tank storage to compensate for the limitation of recovery rate, since for economical electric service the connected load should be kept low. Large tank capacity is necessary also with off-peak operation, where there are low electric rates .for this class of service. 1. Immersion element, inserted horizontally through a . threaded or flanged opening in side of tank: .. 2. Strap-on unit, externally mounted directly against the tank shell and held in close contact by a band or strap encircling the tank. . ' 3. Side-arm or outside circulation unit, consisting of a vertical cylindrical housing or heat exchanger which contains an immersion heating element, connected by pipes into top and bottom of the storage tank For the third type, which is less commonly used, thermo stats separate from the heating units are mounted within the storage tank. . A fourth type of heater, applied only in exceptional cases and for large installations with alternating current, employs the water itself as a resistor in which electrodes are im- Water Services . 757 mereed. Close temperature regulation and compensation for the effect of variable amount and composition of solids and gflfipw in the water are difficult to obtain with small un attended heaters of this kind. The electrode type of con struction has in the past been used also for generating steam in so-called electric boilers, mainly for industrial plants; however, in only few instances today is electric energy ob tainable at cost low enough to make it competitive with fuel- fired boilers for steam production. Tanks of electric heaters are regularly constructed to with stand a 300 psig hydrostatic test pressure and are rated for a safe working pressure of 127.5 psig. Materials in contact with the water are selected to resist corrosion caused by solid and gaseous impurities occurring in some locations. It may be desirable also to provide sacrificial metal anodes of mag nesium, zinc, or alloys to protect the tank and its piping connections. A safety relief valve of pressure-actuated type must be included; it may optionally be actuated also by internal temperature. A heat trap at the hot water outlet, if not provided by manufacturer within or outside the tank shell and inside the insulated jacket, may be placed in the ex ternal piping. The trap consists of vertical pipe at least 6 in. long having downward flow, to retard circulation of hot water within the distribution piping system under standby condi tions. . Occasionally, an uninsulated tempering tank is installed ahead of an electric water heater, enabling the cold inlet water to absorb heat from the basement or room air--if conditions are such that objectionable sweating does not occur. The practice of connecting a tempering tank with a firebox coil, so that the electric heater furnishes heat only when there is deficiency from the boiler or furnace, is not recommended. - Delivery performance efficiency of heaters meeting the electrical-industry standard 24-hour operation test is 90 per cent minimum, which allows 10 percent for thermal loss- through the jacket insulation. In service, the quantity of wa ter withdrawn from an automatic storage heater has con siderable influence on overall efficiency. With increasing quantities, service efficiency rises and approaches the upper limit fixed solely by the jacket thermal loss; on the other hand, if little or no water is drawn, efficiency approaches zero since no useful work is done. Hence oversizing a water heater by having too large a tank impairs the service efficiency. Ex cessive heating-unit wattage causes undesirably high electric demand. Undersizing of beaters obviously results in inade quate and unsatisfactory hot water service. Selection of electric heater capacity for residences is made by reference to rating tables which take into account the number of oceupants, number of bathrooms or plumbing fixtures, and presence of appliances such as laundry, equip ment, dishwashers, and the like. Information of this kind is given in Tables 2, 8, 9 and 10 and in design manuals issued by the electric utility industry and by heater manufacturers. For commercial applications, the hourly hot water require ments must be analyzed and the best combination of tank capacity and heating element rating determined, with due consideration of electric power demand created in relation to the user's other electric demands. A common type of electric service for water heating is the off-peak service under which the charge for energy consumed during designated hours is lower than for normal or unre stricted service. With this system, the operation of heaters is confined to such hourly intervals during the 24 hours as will (a) avoid creating peak electrical demands by the custo mer in excess of the demand resulting from the customer's other uses of electricity, or (6) keep the water heating load off the electric utility system during peak hours. In general, Case (a) occurs where rate schedules contain a demand charge component, and Case (6) where a special low rate applies to off-peak consumption. Water heater circuits are controlled with relays actuated by an electric-clock mecha nism or by a carrier-current impulse impressed at suitable intervals on the electric distribution system, or by an auto matic load-limiting type of control. . For general information on automatic control see Chapter 43. One arrangement of domestic hot water heater for off-peak service, shown in Fig. 8, has the lower heating unit under control of an off-peak switch. Upper unit is connected di rectly to the line, so that if the reserve of hot water becomes depleted, the top thermostat brings its heating unit into op eration only until the upper .portion (usually about 25 per cent) of tank contents reaches the thermostat temperature setting. . Indirect Water Heaters In the indirect method, either steam or hot water is used for heating the water. With steam, the water to be heated is - preferably circulated around the outside of the steam tubes which are submerged within a tank. A typical indirect heater using steam is shown in Fig. 9. The coils usually are of cop per, and are U-shaped to permit expansion and contraction. The shell may be of steel, with a protective coating or with a special inside protective lining, or may be of copper or cop per alloy. Where straight heating tubes are used, one end of the tube is usually expanded into a floating head to take Fig. 8 .... Domestic Hot Water Heater for Off-Peak Service fig. 9____Indirect Water Heater 758 CHAPTER 56 1959 Guide care of expansion. The coils should be capable of easy with drawal for inspection and for removal of scale. Instead of steam, the heating medium may atop be hot water inside the tubes. Another method of transferring heat from a heating boiler to the domestic water is illustrated in Fig. 10- The water heater is generally a cast-iron shell within which there is lo cated a spiral copper coil. Hot water from the boiler circu lates inside t.ho ahpn am) around the coil, and returns to the boiler, while domestic water from the storage tank circulates inside the coil. The storage tank should be installed with the I*Mrtirtttaa Fig. 10 .... Indirect Water Heater Mounted on Side of Boiler inserted through a special opening in the boiler. While the coil may be placed in the stream space above the waterline of a steam boiler, it is usually placed below the waterline. Long coils of small diameter tubing, immersed in the water, are widely used without storage tanks. The rate of flow through the coil is limited by the friction loss in the coil, and by fittings and restrictions, so that the water attains the de sired temperature in one passage through the coil. This ar rangement is frequently found in oil burner installations where the heating boiler, either steam or hot water type, is used to supply hot water during the summer. A thermostatic three-way mixing valve is frequently used to maintain a urnform temperature of the hot water supply to the plumbing fixtures. In order to reduce clogging by precipitated solids, water heating plants sometimes develop steam in a closed circuit, transferring the heat through a tubular heater to the do mestic water. The water in the primary heater, exposed to the high temperature of the fire, is repeatedly used and hence, has no appreciable tendency to deposit scale, while the do mestic water, heated by steam at a much lower temperature than that of the fire, also exhibits a much reduced tendency to precipitate dissolved salts. Water characteristics, the ef fect of impurities, and means of improving the quality of the water are important items, as brought out in Chapter 55. COMPUTING HEAT-TRANSFER SURFACE The area of the inside surface of a heating coil may be de termined from Equation 2. - bottom of the tank as far above the boiler as possible. Hori zontal storage t-anlra of less than 18- or 20-in. diameter are not recommended because of the difficulty of preventing the hot and cold water from mixing, especially when large quan tities of water are withdrawn. In Fig. 11 the heat-transfer surface is placed inside the boiler instead of in a separate vessel, but otherwise the operation is similar to that of Fig. 10. This arrangement with vertical tank is commonly used for small domestic installations. Sometimes the heating element is located inside of the larger-type fire tube boilers and small residential boilers. In this case the heat-transfer surface is in the form of a number of straight copper tubes, with rear U-bends or a floating head. = QX 8.330, ~ Q U XU _ . m where A " surface area of coil, square feet. Q n quantity of water heated, gallons per hour, tt " hot water outlet temperature, Fahrenheit. " cold water inlet temperature, Fahrenheit. ' U -- coefficient of heat transmission, Btu per (hour) (square foot) (Fahrenheit degree logarithmic mean tempera ture difference). - For copper or brass coils U =* 240 (steam) and 100 (hot water). For iron coils U = 160 (steam) and 67 (hot water). Wht Fig. 11.... indirect Water Heater Placed in Boiler r-u. rt f * r t *-* *1 s r 1* _ **'__ i * t * 1 ^ l J'i | ->i * I* 1 t S* {1 ~ i i ' s "l * 1 /li1 > t ) \^ 1 _* * >* i i Fig. 12. ...Methods of Arranging Hot Water Grcuiation Lines Water Services 759 Table 12.... Coefficient of Heat Transfer of Instantaneous Water Heaters U = Btu per (hr) (*q ft) (fah/eehetf degree fegerilfcsMc mean temperature difference) 210 200 180 225 175 150 tions, there should be a separate tapping for water circula tion into every section of to boiler, as shown in Fig. 10, unless to boiler has large top nipple ports providing intersec tional circulation. If the top nipples are entirely within the boiler steam space, no internal circulation occurs between sections. Steaming may then occur in the boiler sections not connected to to heater and, further, to unconnected sec tions will not deliver any heat to the water heater. U = logarithmic mean of the difference between the tem perature of the heating medium and the average water temperature, and is approximately: pT8] t, -- temperature of the heating medium, Fahrenheit. Equation 2 may be used to check the heating coil ratings under temperatures other than those stated in the manufac turer's published ratings. Example 6: What area of copper transfer surface will be re quired to heat 70 gal of water per hour from 40 to 180 F with boiler water at 230 F? Solution: ' U [- ' 110 70 X 8.33(180 - 40) A 7.42 sq ft For instantaneous submerged heaters, the surface required will depend upon (1) the velocity of water in the tubes, (2) the boiler water temperature, (3) the inlet water tempera ture, (4) the outlet water temperature, (5) the cleanliness of the coil surface, and (6) the condition of the boiler water surrounding the coil. If the heater is located in the water of . an actively steaming part of a boiler, the heat transfer may be twice as great as would be obtained if the water surround ing the coil were circulating slowly. Ratings of instantaneous water heating coils will therefore vary greatly, depending upon the assumptions made regarding the conditions of op eration. The values of the coefficient of heat transmission for instantaneous heaters, sbown-in Table 12, are conservative. For a coil in which heat is transferred from steam to water, the value of U = 300 y/v may safely be used (v = velocity of water in feet per second). The rate of heat transfer, between steam or water as the carrier, and the domestic water, is influenced by the rate of movement of both to carrier and to water which re ceives the heat. For this reason, where to transfer occurs from heating system water to domestic water, it is good practice to install a circulating pump to insure rapid move ment of the boiler water. In view of to high condensation rates obtained when steam is used with gravity circulation from the boiler, particularly when there is a sudden demand followed by an inflow of cold water, the bottom of a steam heat transfer element always should be.at least 30 in. above the boiler water line, and the steam and condensate return pipes should be of liberal size. Otherwise, water hammer and reduced capacity may result, due to imperfect drainage of condensate. When connecting a transfer-type hot water heater below the waterline of a cast-iron steam boiler having vertical sec HOT WATER SUPPLY PIPING It is common practice to provide circulating piping in all hot water supply systems in which it is desirable to have hot water available continuously at the fixtures. In average sized and small residences and systems, in which to piping from the heater to to fixtures is short, return circulating piping is generally omitted in order to reduce installation cost, and to reduce heat loss from the piping, particularly during periods of no water demand. The hot water supply may be distributed by either an up- feed or down-feed piping system. Three common methods of arranging the circulating lines are shown in Fig. 12. Although the' diagrams apply to multi-story buildings, the arrange ments (a) and (6) are sometimes used in residential designs. A check valve should be provided in the runout from each return riser to prevent temporary reversal of flow in the piping when a faucet is open. Proper air venting of a circu lating system is extremely important, particularly if gravity circulation is employed. In Fig. 12 (a) and (b), this is ac complished by connecting the circulating line below the top fixture supply. With this arrangement, air is eliminated from the system each time the top fixture is opened. Where an overhead supply main is located above to high est fixture as in Fig. 12 (c), an automatic float-type air vent is installed at the highest point of the system, or a fixture branch is connected to the top of the main where air venting is desired, and then dropped to the fixture outlet. It is sometimes necessary to make an allowance for pres sure drop through the heater when sizing hot water lines, particularly where instantaneous hot water heaters are used and the available pressure is low. - The principles involved in the rising of the hot water sup ply pipes are the same as those for the sizing of cold water supply lines. For small and medium sized installations a 34-in. hot water return will be ample. For larger installations, the size of to hot water return may be computed from considera tions of to heat losses in the hot water piping.* A throttling valve should be placed in to hot water return pipe so that the rate of circulation may be adjusted. Where the hot water piping system is exceedingly long, a water circulator is frequently installed. It is controlled by an immersion thermostat (in the return line) set to start and stop the pump over approximately a 20 F deg temperature range. In calculating to pump capacity, the product of (1) X to pounds of water circulated and (2) the temperature dif ference (usually 20 deg) between the flow and return, must be equivalent to the Btu heat loss from to piping at to average temperature of the water. Insulation reduces the heat loss and pump capacity required. The friction head against which the pump must operate may be calculated from the tables and charts in Chapter 28, Hot Water Heating Sys tems. The friction bead seldom exceeds 6 to 10 feet. Since service water is corrosive due to the high oxygen content and high temperature, circulating pumps should be made of bronze. 760 CHAPTER 56 1959 Guide CONTROL OF SERVICE WATER TEMPERATURE Coal-fired boilers are usually controlled by an immersion thermostat (located in the heated water) which opens or closes draft dampers at the boiler to adjust the rate .of fuel combustion. With oil- or gas-fired boilers, the immersion thermostat controls the oil burner or the automatic gas valve. The gas pilot flame usually bums continuously. With electric heaters, the immersion thermostat operates a switch on the source of energy. ' When steam or hot water is the medium for heating the water in the tank, an immersion thermostat is used to con trol a valve in the steam or hot water,supply line. In small residence installations, using water as the carrier, a com-' bined immersion thermostat and butterfly valve in one sim ple fitting may be installed in the transmitting circuit to prevent overheating of the service water. In residences heated by pump-circulated hot water, the house temperature is controlled by operating the circulating pump intermittently, while domestic hot water is warmed by transfer from the house boiler, independent of the pump operation. The domestic water is heated from the heating boiler the year-round. Under such an arrangement, to pre vent overheating the house by thermal circulation when the pump is not running, it is usual to insert a weighted check valve in the house heating main so that no circulation to the house heating system can occur unless the pump operates. In summer the fire may be controlled to maintain a boiler water temperature lower than' when heating, and generally about 20 F warmer than-that desired in the domestic hot water system. . The immersion thermostat in a hot water storage tank should be located no higher than the center of the tank, and possibly should be even closer to the bottom, since water in a tank stratifies proportionally to the temperature. When hot water is removed, the cold water entering to replace it quickly reduces the temperature in the lower parts of .the tank. * For general information on automatic control see Chapter 43. SAFETY DEVICES FOR HOT WATER SUPPLY SYSTEMS There are still numerous plumbing codes which do not have regulations for the prevention of hot water storage tank ex plosions. . An ordinary storage tank is under certain water pressure, depending on the static pressure in the system. When the . water in the tank is heated by circulation through an ex ternal heater, or by heating units in the tank, it gradually expands. For instance, if the entire contents of a 30-gal storage tank are heated from 70 F to 160 F, there will be an - increase in volume of about one-half gallon. If the tank is connected to a supply line without any intervening check valve, the increase in volume causes part of the water to be pushed back into the supply line. If the hot water reaches the water meter, it may ruin the composition discs. If back-flow cannot occur, as for example, due to the use of a check valve or a pressure-reduction valve in the line, or because of temporary shut-off of the cold water line, the pressure in the tank rises as heating continues. Such a pres sure rise, if the heating continues for any length of time, may result in rupturing of the tank. If the tank water is not confined, continued heating would, of course, cause no increase in pressure beyond ordinary line pressure. However, the temperature would continue to in crease. If this should happen at elevated temperatures, the flashing of the water into steam might cause a serious tank explosion. In order to guard against the development of excessive pressure inside a hot water storage tank (owing to the ther mal expansion of the water), it is customary to-install a spring-loaded pressure-relief valve which is set to open at a .pressure about 20 psi higher than the normal line pressure. The amount of water discharged by any pressure-relief device is usually quite small, since it takes only a small quan tity of water to relieve any pressure rise due to the thermal expansion of the water. The rate of discharge should be such as to limit the pressure rise for any given heat input to 10 percent of the pressure at which the valve is set to open. For any given installation, the discharging capacity should be in excess of the water to be discharged by the heater. The heater discharge Qm in gallons per minute may be computed by Equation 3: Q, - 0.00005b (3) where b is the heat input of heater in Btu per minute. To prevent danger of overheating, temperature-relief de vices should be used. One type of such a device has a fusible plug of metal which melts at about 212 F. The hot water then runs from the opening until the device is serviced. A better type of relief device is one which incorporates a bellows or bimetallic disc, which opens at a temperature of 210 F and closes when the temperature drops to approximately 160 F. Another type of safety device is a fuel cut-off switch or valve in which a fusible plug is melted by excessive water temperature. The fuel supply is cut off until the fusible plug is replaced. `. The capacity of temperature-relief devices may be calcu lated by Equation 4: Qm = 0.0008b (4) where and b denote the same quantities as in Equation 3. Pressure-relief valves should be installed in the cold water line near the tank out of contact with the hot water in order to prevent excessive corrosion and lime deposit on the valve seat. Temperature-relief valves, in general, must be installed at the point of maximum water temperature. SOLAR WATER HEATERS Solar heaters utilize the energy of the sun for heating wa ter. The successful operation of such heaters requires the Wafer Services 761 Dragrt (tom Table 13 .... Suggested Solar Heater Design Data* Based on Rate of 30 Gal per Day per Person Sated on Rate of 40 Get per Day per Person No. of occupants in residence............. ... ... 1 2 3 4 5 6 7 8 i 2 3 4 5 6 7 8 Hot water used at night, gal per person.. 15 15 15 15 15 15 15 15 20 20 20 20 20 20 20 20 Hot water used at night, gal total............ 15 30 45 60 75 90 105 120 20 40 60 80 100 120 140 160 Retained in tank, 25 percent, gal.............. 4 8 11 15 19 23 27 30 5 10 15 20 25 30 35 40 Tank capacity required, gal........................ 20 40 59 75 94 113 130 150 25 50 75 100 125 150 175 200 Hot water used during day, gat................. 15 30 45 60 75 90 105 120 20 40 60 80 100 120 140 160 Total water to be heated: Gal per 8-br period..................... :.............. 35 70 104 135 169 203 235 270 Gal per hour.................................................. 4.5 9 13 17 21 26 29 34 45 90 135 180 225 270 315 360 6 12 17 23 28 34 39 45 Copper coil required: Surface area, sq ft....................................... 25 60 75 100 121 145 168 192 32 64 96 128 160 192 224 256 Equivalent length 1-in. coil, ft............... 100 200 300 400 484 , .580 664 768 128 256 384 512 640 .768 896 1024 Box size: Area, sq ft...................................................... Width, ft......................................................... Length,ft....................................................... 25 4 6 50 75 100 121 145 168 192 678 9 10 10 8 11 12.5 13.5 14.5 16.5 * 8ud Effect and the Desicn of Solar Heaters, by H. L. Alt {ASHVK Tsajcsactiohs, Vat.-41, IRS, p. 131). 32 64 96 128 160 192 224 256 4 6 8 9 10 11 12 12 8 10 12 14 16 18 19 21 availability of sunshine practically every day in the year, which has limited their use to Florida and the southern por tions of California. When supplemented with some other means of gas, coal, or oil water heating, solar heaters may be used in climates where sunshine may be more or less inter mittent. They have been used in summer homes as far.north as Chicago. When properly installed and proportioned, solar water heaters render satisfactory service, especially in cli mates where the outdoor temperatures are high and extremely hot water is not necessarily desirable. Such installations con sist essentially of a storage tank, heating coil, and hot box. The coil is installed in the hot box, and is arranged to circulate water to and from the storage tank. The advantage in the use of this type of heater is the fact that it requires no fuel. The same materials should be'used for the coil, circulation fines, and tank. A copper coil is more efficient in absorbing heat in the box, but galvanized iron or steel may be sub stituted, depending on the local water conditions, cost, and other considerations. The storage tank must be able, to store sufficient heated water for the night period of about 16 hr when the coil is not functioning, or is operating under such poor nn condi tions as to make its heating effect negligible. Due to the fact that the no sun period includes the night period when little or no hot water is used, an available storage of 50 percent of the average daily usage is considered adequate. Since about 25 percent of stored hot water cannot be drawn out of a storage tank before the incoming cold water reduces the tem perature pf all of the water in the tank to an unsatisfactory point for usage, the equation for calculating the storage ca pacity of the tank becomes: where 8 = storage capacity of tank, galloos. Qj *= average daily usage, gallons. Thus, for a family of four persons using an average of 40 gal of hot water per (person) (day), the size of the tank would be 4 persons x 40 gal x 0.666 or 106 gal, and the nearest standard size of tank would be used. The tank should be well insulated to prevent undue loss of heat during the 16-hour period when the coil is inoperative, and it should be located as high as possible in the building (under the peak of the roof if such exists) so as to secure a maximum circulation head from the coil. The hot water supply line to the house, as shown in Fig. 13, is connected to the top of the tank and serves to vent the air from the tank through the hot water faucets as fast as it accumulates. 0.75 Fig, 14....Solar Heating Coil Inclination 762 CHAPTER 56 1959 Guide The coil should be of the return-bend type (square or slightly rectangular in form), and should have the pipes run ning east and west, with the coil on the south side of the building where it can receive the full sun effect all day long without shadows from the building .itself, or from the ad jacent obstructions such as trees or other structures. The coil should be placed as low as possible in relation to the storage tank level, such as on a porch roof, the roof of a one-story extension or, if necessary, even on the ground. Both the coil and the circulation lines should be designed to facilitate the circulation flow as much as possible, using long-radius copper fittings or recessed galvanized-iron fittings to match the materials of the coil, circulation lines, and tank. The coil should be inclined, as shown in Fig. 14, so that the north end is raised above the south end to secure an angle with the horizontal of about 53 deg. This will result in the inlet end of the coil being on the south side (or bottom), and the outlet end being on the north side (or top). This will satisfy condi tions along the 30-deg N latitude, which includes the por tions of Florida and Southern California where these heaters are most frequently used. The hot box is usually constructed of wood on the four sides and bottom, and is insulated. Glass mh are placed over the top of the box which should be airtight. The interior sur faces should be painted white to reflect the heat, while the coil should be painted black to absorb the heat. The box need not be deeper than necessary to house the coil and to protect it from the weather. The addition, on the bottom of the box, of a light gage copper plate to which the pipe of the coil is soldered for good metallic contact, will add to the amount of heat received by the coil, due to the fact that this plate will receive all of the sun's rays which fail to directly strike the coil. The heat from this source is transmitted to the coil through the plate rather than from the heated air surrounding the coil. Other wise, only part of the heat enters the coil, the balance being transmitted through, the glass. Design data given in Table 13 may be used with judgment in selecting the size of solar heater coil and box for a partial- . lar application. These data are based on consumptions of 30 and 40 gal of hot water per (day) (person). Fig. 15.... Heat Pump Arrangement for Hot Water Supply DOMESTIC HOT WATER BY HEAT PUMP Hot water may suitably be obtained by using a heat-pump installation. The hot water heater may be either a heat ex changer installed just ahead of the compressor of a heat- pump installation, or may be a self-contained domestic-water heat pump. Various designs of self-contained domestic water heat pumps are available, and one particular arrangement is shown in Fig. 15. , Hot water heating by means of a heat pump is not yet ad visable where high water temperatures are desired. This is- due to the fact that higher water outlet temperatures result in lower coefficients of performance. For coefficients of performance of 4 or higher, the heat- pump water heater may be more economical to operate than a conventional water heater. Although the first cost of domestic hot water heat pumps is somewhat high, they have the advantages of operating with out products of combustion, odors, soot, or chimney. A further advantage is that they may be used for cooling pur poses. With a coefficient of performance of 2)4 to 3, water temperatures of 140 to ISOF may be obtained* REFERENCES 1 R. B. Hunter: Water Distributing Systems for Buildings {National Bureau of Standards Report BMS79, p. 6). (Charts extended to flow of 020 gpm.) . . * Private communication from H. E. Degler. *J. S. Setchell: Enough Hot Water--Hot Enough (Ameri can Gas Association, 1950). `Svend Plum: Plumbing Practice and Design (John Wiley ' and Sons, New York, 1943). * P. Sporn and E. R. Ambrose: Progress report on a heat* pump water heater {Heating and Ventilating, Vol. 46, February 1949, p. 78). BIBLIOGRAPHY H. C. Russell: Laundiy, kitchen and hospital equipment (ASHVE Transactions, Vol. 35, 1929, p. 45). G. C. St. Laurent: Water consumption, cost and savings {Hotel Engineering, Vol. 1, American Hotel Association, 1940). F. M. Dawson and A. A. Kalinske: Water-Supply Piping for the Plumbing System (National Association of Master Plumbers Technical Bulletin No. 3). F. A. Brooks: Use of Solar Energy for Heating Water (Smithsonian Institution, Washington, D.C.). R. B. Hunter: Methods of Estimating Loads m Plumbing Systems {National Bureau of Standards Report BMS65, 1940). Plumbing Maraud, Report of the Subcommittee on Plumbing, Central Housing Committee on Research, Design and Con struction {National Bureau of Standards Report BMS66, 1940). R. B. Hunter: Water-Distributing Systems for Buildings {National Bureau of Standards Report BMS79, 1941). M. B. Mackay: Hot water requirements {Modem Sanitation, Vol. 1, August 1949, p. 30). - M. A. Pond: Urban domestic water consumption {Journal of the American Water Works Association, VoL 31, No. 12, 1939, p. 2003). R. Murray: How to size and install gas water heaters cor rectly {Air Conditioning, Heating and Ventilating, February 1955, p. 86). J. C. Church: Water supply for tall buildings {Air Condition ing, Heating and Ventilating, February 1955, p. 99). F. M. Reiter: Service hot water design for multi-story build ings {Air Conditioning, Heating and Ventilating, December 1955, p. 79). F. M. Reiter: Service hot water for commercial and industrial use {Air Conditioning, Heating and Ventilating, February 1956 p. 89). F. M. Reiter: Design data for service hot water {Air Condi tioning, Heating and Ventilating, April 1956, p. 81). G. R. Jerus: Design of swimming pools (Air Conditioning, HeaUng and Ventilating, February 1957, p. 113). . J. Nachbar: Water supply for industrial plants (Air Condi tioning, Heating and Ventilating, December 1957, p. 53). CHAPTER 57 CODES AND STANDARDS HE Codes and Standards listed in Table 1 represent accepted practice, methods, or standards prepared and accepted by the Torganizations indicated. They are valuable guides for the practicing engineer in determining test methods, ratings, perform ance requirements, and limits applying to equipment used in heating, ventilating, and air conditioning. Copies can usually be obtained from the organization listed in the reference column. Table 1 .... Codes and Standards Prepared and Accepted by Various Societies and Associations SubjMt n* Acoustics (Terminology) American Standard Acoustical Terminology (1951). AS of A ASA Air Conditioners Air Conditioners (Room) Air Conditioning Air Conditioning (120,000 Btu/hr or less) Air Conditioning (Above 120,000 Btu/hr) Air Conditioning Air Conditioning Air Conditioning (Residen tial) ' Air Conditioning (Unitary Equipment) Air Conditioning (YearRound Residential) Airplane Airplane Airplane Attic Ventilation Boilers Boilers Boilers Boilers Boilers Boilers (Gas) Boilers (Miniature) Boilers (Power) Boilers (Power) Boilers (Steel) ASRE Standard Methods of Rating and Testing Air Condi tioners (1956). Standards for Room Air-Conditioners. ASRE ARI Code of Minimum Requirements for Comfort Air Condition ing (1938). Code and Manual for the Design and Installation of Warm Air Winter Air Conditioning Systems (1953). ASHVE ASRE NWAH & ACA Code and Manual for the Design and Installation of Mechani NWAH & ACA cal Warm Air Heating Systems (1950). Standards for the Installation of Air Conditioning and Ven tilating Systems of Other Than Residence Type (1955). Standards for the Installation of Residence Type Warm Air Heating and Air Conditioning Systems (1956). Design and Installation of Summer Air Conditioning for New and Existing Residences, Tentative (1955). Standard for Unitary Air Conditioning Equipment. NFPA NFPA NWAH A ACA ARI Standard for Year-Round Residential Air-Conditioning. ARI Air Conditioning Equipment, Airplane--General Require ments for (1948). Heaters, Airplane, Internal Combustion Heat Exchanger Type (1949). Heaters, Airplane, Steam Type. Residence Ventilation Guide (1950). T=B=R Testing and Rating Code for Low Pressure Cast Iron Heating Boilers, 6th Edition, 1958. Net Load Recommendations for Heating Boilers. Publ. semi annually. Net Square Feet Radiation Loads in 70 Deg Fahr, Recom mended for Low Pressure Heating Boilers (1948). ASME Boiler and Pressure Vessel Code (1956, 8 Sections). ASME Boiler and Pressure Vessel Code, Section IV, Low Pressure Heating Boilers (1956 with 1957 and 1958 addenda). American Standard Approval Requirements for Central Heating Gas Appliances Vol. 1, Steam and Hot Water Boilers (1956). ASME Boiler and Pressure Vessel Code, Section V, Miniature Boilers (1952). ASME Boiler and Pressure Vessel Code, Section I, Power Boilers (1956). ASME Boiler and Pressure Vessel Code, Section VII, Sug gested Rules for Care of Power Boilers (1954). Steel Boiler Institute Rating Code for Steel Boilers (1958). SAE SAE SAE PFMA IBR HP A ACCNA HP AACCNA ASME ASME A.GA. ASME ASME ASME SBI ASRE Standard 16-56 ARI Standard 110-58 ASHAE NWAH A ACA Manual No. 7 . 4th Edition NWAH A ACA Manual No. 9 5th Edition NBFU or NFPA No. 90A NBFU or NFPA No. 90B NWAH A ACA Manual No. 11 AK1 Standard ARI Standard 230-57 SAE ARP 85B SAE ARP 143B SAE ARP 87 PFMA IBR MCAA MCAA ASME ASME ASA Z21.13.1-1956 ASME ASME ASME SBI Boilers (Steel) Simplified Practice Recommendation for Steel Firebox Boil ers and Steel Heating Boilers (Commercial and Residential Types) (1950). BS SBI CSD R157-50 763 764 CHAPTER 57 1959 Guide Table 1 .... Codes and Standards--(Continued) Subject T7ff* Sponsor Coforanc* Buildings Building Requirements Buildings Burners (Anthracite) Burners (Gas) - Burners (Gas) National Building Code (1955 Edition). American Standard Building Requirements (1946). Basic Building Code (Also published in abridged form as Abridged Building Code) 1955. Commercial Standard for Domestic Burners for Pennsyl vania Anthracite (Underfeed Type) (1940). American Standard Requirements for Installation of Domes tic Gas Conversion Burners (1948). Reaffirmed 1952. American Standard Requirements for Installation of Gas Burning Equipment in Large Boilers (1950). Reaffirmed NBFU NHA USPHS BOCA BS AIL A.G.A. A.G.A. NBFU ASA A53.1-1946 BOCA CSD CS48-40 ASA Z21.8-1948 ASA Z21.33-1950 Burners (Gas) Burners (Oil) Burners (Oil) Burners (Oil) Burners -(Pulverized Coal) Chillers Chimneys (Flue Linings) American Standard Listing Requirements for Domestic Gas Conversion Burners (1948). Reaffirmed 1952. Commercial Standard for Mechanical-Draft Oil Burners Designed for Domestic Installations (1956). Standards for the Installation of Oil Burning Equipment (1956). Standard for the Installation of Residential Oil-Fired Cen tral Heating Equipment (1958). Standards for the Installation of Pulverized Coal Systems (1956). ' Liquid-Chilling Packages with Reciprocating Compressors (2HP and Larger) (1956). American Standard Sizes of Clay Flue Linings (1947). Cleaners (Air) Coal (For Stokers) Coils Code for Testing Air Cleaning Devices Used in General Ven tilation: Section I, Unit or Panel Type Air Filtering De vices (1953). Tentative Standard Procedure for Testing and Evaluating Bituminous Stoker Coals (1952). Proposed Commercial Standard for Rating and Testing Air Cooling Coils Using Nonvolatile Refrigerants (1945). Joint ASRE-ASHAE Standard Methods of Testing and Rat ing Forced-Circulation Air Heating and Air Cooling Coils. Color Scheme (Piping) Scheme for Identification of Piping Systems (1956). Color Scheme (Piping) Scheme for Identification of Piping Systems (1956). Compressors ASRE Standard Methods of Rating and Testing Refrigerant Compressors. Compressors (Reciprocat ing) Condensers Standard Nomenclature for Reciprocating Compressors. ASRE Standard Methods of Rating and Testing Evaporative Condensers. - Coudensers ASRE Standard Methods of Rating and Testing WaterCooled Refrigerant Condensers. Condensing Units ASRE Standard Methods of Rating and Testing Mechanical Condensing Units (1940). . Conductance Conductivity Method of Test for Thermal Conductance and Transmittance of Built-up Sections by Means of Guarded Hot Box (1949). Standard Method of Test for Thermal Conductivity of Ma terials by Means of the Guarded Hot Plate (1945). Control Equipment (In dustrial) Controls Controls Temperature Controls Temperature ` Underwriters' Laboratories, Inc., Standard for Industrial ' Control Equipment (July, 1938). Underwriters' Laboratories, Inc., Standard for Temperature Indicating and Regulating Equipment (June 1953). NEMA Standards for Automatic Temperature Controls (1953). Temperature Control Equipment, Automatic, Airplane A.G.A. BS OBI NFPA OHIA NFPA ARI AIA PC AFI ASA Z21.17-1948 CSD CS75-56 NBFU or NFPA No. 31 OHIA B-68 NBFU or NFPA No. 60A ARI Standard 590-56 ASA A62.4-1947 AFI SMA BCR BC . BS ASHAE ASRE HP & ACCNA ASME ASRE ASHVE ACRMA ARI ASRE ASHVE ACRMA ASRE ASHVE ACRMA ASRE ASHVE ACRMA ASTM . ASHVE ASRE ASTM NRC UL UL NEMA SAE SMA BCR CSD TS 4044 ASRECircular No. 33-58 MCAA Engrg. Std5., Sec. 2, Part V ASA ' A13.1-1956 ASRE Standard 23-R ARI Standard 510-57 ASRE Standard 20 ASRE Standard 22 ASRE Standard 14-41 ASTM C 236-49 T ASTM C-177-45 UL Subject 508 . UL Subject 873 NEMA DC1-1953 SAE Convectors Commercial Standard for Testing and Rating Convectors (1947). BS CMA IBR CSD CS 140-47 Codes and Standards 765 Table 1 .... Codes and Standards--(Continued) Subjoc* Htto Sponsor Kebmcs Coolers (Air) ASRE Standard Methods of Rating and Testing Forced Cir culation and Natural Convection Air Coolers for Refrigera tion (1945). Coolers (Air) Coolers Cooling Towers Cooling Towers (Mechani cal Draft) Cooling Towers Forced-Circulation Free-Delivery Air Coolers for Refrigera tion. ASRE Standard Methods of Rating and Testing Liquid Coolers. ` Accepted Test Procedure for Water Cooling Towers, Me chanical Draft, Industrial Type (1955). Method of Testing for Rating Mechanical Draft Cooling Towers Under Controlled Conditions. Standard for Mechanical Draft Cooling Towers Ducts and Fittings Exchangers (Heat) Exhaust Systems Simplified Practice Recommendation for Pipes, Ducts and Fittings for Warm Air Heating and Air Conditioning (1945). Standards of Tubular Exchanger Manufacturers Association (1941). American Standard for Grinding, Polishing, and Buffing Equipment Sanitation (1941). ASRE ASHVE ACRMA REMA ARI ASRE CTI ASRE ARI Mfre. BS TEMA ` AFA ASRE Standard 25-44 ARI Standard 420-57 ASRE Standard 24-57 CTI Bulletin ATP-105 ASRE Standard 38-57 ARI Standard 910-58 CSD R207-49 TEMA ASA Z43-1941 Exhaust Systems Exhaust Systems Exhaust Systems Tentative Code of Recommended Practices for Testing and Measuring Air Flow in Exhaust Systems (1937). Tentative Recommended Good Practice Code and Handbook on the Fundamentals of Design, Construction, Operation and Maintenance of Exhaust Systems. Standards for Blower and Exhaust Systems (1949). o AFA AFA NFPA AFA Preprint 36-27 AFA NFPA or NBFU Exhaust Systems (Open Tanks) - Fans - Fans Fans Fans Fans Fans Fans Fire Prevention Furnaces (Duct) Furnaces (Gas) Furnaces (Forced Air, Solid-Fuel) American Standard Safety Code for Ventilation and Operation of Open-Surface Tanks (1951). Definitions and Terms in Use by the Blower Industry (1950) (Was NAFM Bulletin No. 105). Standard Test Code for Testing Centrifugal and Axial Fans (1950) (Was NAFM Bulletin No. 103). Standard Code for Testing Centrifugal, Axial, and Propeller Fans. (Having Wheels Less'than 12-in. Dia). 1953. Standards, Definitions, Terms and Test Codes for Centrifu gal, Axial and Propeller Fans. Standards Publication Electric Fans (1955). Test Code for Fans (1946). Testing and Rating Ventilating Fans (Axial and Propeller Type)- ' National Fire Codes (1954). Von. I--Flammable Liquids and Gases, Vol.II--Combustible Solids, Dusts, Chemicals, and Explosives, Vol. Ill-- Building Construction and Equipment, Vol. IV--Extin guishing Equipment, Vol. V--Electrical, Vol. VI--Trans portation. American Standard Approval Requirements for Gas-Fired Duct Furnaces (with 1956 and 1957 Addenda). American Standard Approval Requirements for Central Heating Gas Appliances Vol. II, Gravity and Forced Air Central Furnaces (1956). Commercial Standard for Solid-Fuel-Burning Forced Air Furnaces (1944). AIHA ASHVE NAFM NAFM NAFM* ASHVE NAFM NAFM ASHVE** NEMA ASME CSD NFPA A.G.A. A.GA. FHA NWAH & ACA ASA Z9.1-1951 NAFM-AMCA Bulletin No. 110 NAFM-AMCA Bulletin No. 110 NAFM-AMCA Bulletin No. 116 NAFM-AMCA Bulletin 110 2nd Edition, 1952 NEMA FM1-1955 ASME PTC 11-1946 CSD NFPA ASA Z21.34-1955 ASA Z21.13.2 1956 CSD CS109-44 Furnaces (Heavy Duty) Furnaces (Oil-Fired) Furnaces (Oil-Fired) Furnaces (Oil) Code for Testing and Rating Heavy Duty Furnaces and Direct-Fired Unit Heaters (1955). Commercial Standard for Warm Air Furnaces Equipped with Vaporizing Type Oil Burners (1949). Recommended Commercial Standard for Warm Air Fur naces Equipped with Pressure Atomizing or Rotary Type Oil Burners. Commercial Standard for Oil Burning Floor Furnaces Equipped with Vaporizing Type Burners (1951). ASHAE Mfre. BS BS NWAH & ACA BS OPA ASHAE CSD C8104-49 .CSD CS19S-54 CSD CSl 13-51 * Abo eadoraod by PFMA. Refen to Test Code for CentrifunJ sod Ain) Peas. 766 CHAPTER 57 1959 Guide Table 1 .... Codes and Standards--(Continued) ntfe Sponsor Mswati Furnaces (Oil) Garage Ventilation Garages Gas Equipment (Large Boilers) Gases (Toxic) and Dust Hangars Aircraft Heat Pumps (Unitary Equipment) Heat Transfer (Walls) Heaters (Recessed Gas Fired) Heaters (Room Gas Fired) Homes (Prefabricated) Mineral Wool Mineral Wool Mineral Wool ' Motors A Tentative Code for Testing Oil-Fired Furnaces. . Recommended Good Practice Requirements for the Con struction and Protection of Garages (1932, Reprint 1952) Code of Minimum Requirements for Heating and Ventilating Garages (1935). American Standard Requirements for Installation of Gas Equipment in Large Boilers (1950). Reaffirmed 1956. American Standard Allowable Concentration of Harmful Gases: Carbon Monoxide - Hydrogen Sulfide Carbon Disulfide Bensene ' Manganese . Chromic Acid and Chromates ' Mercury Xylene Lead and Certain Inorganic Lead Compounds Toluene Oxides of Nitrogen Methanol - - Styrene Monomer Formaldehyde Carbon Tetrachloride Methyl Chloride Trichloroethylene ' ' Standard for the Construction and Protection of Aircraft Hangars (1954). Standard for Unitary Heat Pump Equipment. NWAH & ACA NFPA ASHVE A.G.A. ASA NFPA ARI Thermal Conductance and Transmittance of Built-up Sec tions by Means of Guarded Hot Box (1949). Atneriean Standard Approval Requirements for Central Heating Gas Appliances, Vol. IV Gravity and Fan Type Vented Recessea Heaters (1955 with 1956 and 1957 Ad denda). American Standard Approval Requirements for Gas-Fired ' Room Heaters (formerly called Space Heaters) (1956). Commercial Standard for Prefabricated Homes Commercial Standard for Mineral Wool Insulation for Heated Industrial Equipment (1949). Commercial Standard for Mineral Wool Insulation for Los Temperature Installations (1948). Recommended Commercial Standard for Industrial Mineral Wool Products--All Types--Testing and Reporting (1946). Nema Motor and Generator Standards (June 1945). ASTM A.G.A. A.G.A. PHMI BS BS IMWI BS IMWI IMWI BS NEMA Motors Test Code for Single-Phase Motors (1941). AIEE Panel System (Warm Air) Code and Manual for the Design and Installation of Warm NWAH A ACA Air Ceiling Panel Systems (1950). Perimeter (Warm Air Small 4-Inch Pipe Warm Air Perimeter Heating (1956). Pipe) Perimeter (Warm Air) Warm Air Perimeter Heating (1956, 5th Edition). NWAH A ACA NWAH A ACA Pipe A Tubing (Copper & Brass) Piping Simplified Practice Recommendation for Copper Water Tubes and Brass Pipe. American Standard Code for Pressure Piping (1955) Piping (Gas) Pumps Radiation' (Baseboard) American Standard for Installation of Gas Piping and Gas Appliances in Buildings (1954). Hydraulic Institute Test Code for Centrifugal Pumps. Hy draulic Institute Test Code for Rotary Pumps (1943). I=B=R Testing and Rating Code for Baseboard Type of Radiation (1950). BS ASME A.G.A. HI IBR NWAH A ACA NFPA Pamphtet No. 88 ASHAE ASA 221.33-1950 . ASA Z37.1-1941 Z37.2-1941 Z37.3-1941 Z37.4-1941 Z37.6-1948 Z37.7-1943 . Z37.8-1943 Z37.10-1948 Z37.U-1943 237.12-1943 Z37.13-1944 Z37.14-1944 237.15-1944 Z37.16-I944 Z37.17-1957 237.18-1949 - Z37.19-1946 NBFU or NFPA No. 409 ARI Standard 510-57 ASTM C-236-49 T ASA Z21.13.4-1955 ASA Z21.11-1956 CSD CS125-47 CSD C8117-49 CSD CS105-48 CSD CS131-46 NEMA 45-102 AIEE Report 502 NWAH A ACA . Manual No. 7-A 3rd Edition NWAH A ACA Manual No. 10 4th Edition NWAH A ACA Manual No. 4 . CSD R217-49 ASA B31.1-1955 ASA 221^0-1954 HI Section F IBR Codes and Sfandards 767 Table 1 .,.. Codes and Standards--(Continued) Subject ` fiffe ` Sponw Reference Radiation (Finned-Type) Radiators Refrigerants J = B-It Testing and Rating Code for Finned-Type Radia tion (First Edition 1951, with Addenda 1954). Simplified Practice Recommendation for Cast Iron Radiators (1943). Standard Designation of Refrigerants. Refrigeration (Equipment) Underwriters' Laboratories, Inc., Standard for Air Condi tioning and Commercial Refrigerating Equipment (Feb. IBR IBR BS ASHE UL IBR CSD R174-47 ASRE Standard 34-57 UL Subject 207A Refrigeration (Mechanical)- Refrigeration (Unit Systerns) Refrigerators (Gas-Fired) Refrigerators (Household) American Standard Safety Code for Mechanical Refrigeration (1958). Underwriters' Laboratories, Inc., Standard for Unit Refrigcrating Systems (Feb. 1946). American Standard Approval Requirements for Refrigerators Using Gas Fuel (1942, Reaffirmed 1950). American Standard Test Procedures for Household Electric Refrigerators (Mechanically Operated) (1944). Reaffirmed ASRE UL A.G.A. ASRE USDA ASA B9.1-1958*** UL Subject 207C ASA Z21.19-1941 ASA B38.2-I944 Sound (Measurement) Sound (Measurement) Sound (Measurement) American Standard for Sound Level Meters for Measurement of Noise and Other Sounds. American Standard Method for the Pressure Calibration of Laboratory Standard Pressure Microphones. Sound Measurement Test Code for Centrifugal and Axial Fans (1050) (Was NAFM Bulletin No. 104). Sound (Measurement) Sound Measurement Test Code for Unit Heaters (1955). Space Heaters Stokers Stokers Stokers . Stokers Tubing (Seamless Copper and Copper Alloy) Tubing (Seamless Copper Water Tube) Unfired Pressure Vessels Unit Heaters Unit Heaters Unit Heaters Commercial Standard for Flue Connected Oil-Burning Space Heaters Equipped with Vaporising Pot-Type Burners (1943). Code for Determination of Rated Capacities of Anthracite Underfeed Stokers (1944). Code for Determination of Rated Capacities of Bituminous Underfeed Stokers (1944). Recommended Minimum Firebox Dimensions and Base Heights (1944). -- Recommended Standards' Governing Minimum Setting Heights (1944). Simplified Practice Recommendation for Copper and CopperAllov Round Seamless Tube (1948). Standard Specifications for Seamless Copper Water Tube (1956). ASME Boiler and Pressure Vessel Code Section VIII, Un fired Pressure Vessels (1956). American Standard Approval Requirements for Gas Unit Heaters (1957). Standard Code for Testing and Rating Steam Unit Heaters (1950). Standard Code for Testing Hot Water Unit Heaters (1942). Unit Ventilators Vacuum Pumps Warm Air (Uravity) ASHVE Standard Code for Testing and Rating Steam Unit Ventilators (1934). ASHVE Standard Code for Testing and Rating Return Line Low Vacuum Heating Pumps (1934). Gravity Code and Manual for the Design and Installation of Gravity Warm Air Heating Systems (1954). Water Heaters Water Heaters Water Heaters Water Heaters Wiring Wiring American Standard Household Automatic Electric Storagetype Water Heaters. American Standard Approval Requirements, for Gas Water Heaters Volume 1 (1956). NEMA Standards for Electric Water Heaters (1945). Testing and Rating Hand-Fired Hot Water Supply Boilers (1948). Interior Wiring Design for Commercial Buildings. National Electrical Code (1956). . AS of A AS of A NAFM IUHAICHAM SMA SMA SMA SMA BS ASTM . ASME . A.G.A. ASHVE IUHA IUHA ASHVE ASHVE NWAH A ACA NEMA A.G.A. NEMA FHA AIEE NFPA ASA Z24.3-1944 A8A 224.4-1949 NAFM-AMCA Bulletin No. 110, 1950 IUHA-AMCA Bulletin No. 13 CSD CS1Q1-43 SMA SMA SMA SMA CSD R235-48 ASA H23.1-1956 ASME ASA Z21.16-1957 IUHA-AMCA Bulletin 10 IUHA-AMCA Bulletin 11 ASHAE ASHAE NWAH A ACA Manual No. 5 5th Edition ASA C72.1-1949 ASA 221.10.1-1956 NEMA 45-104 CSD CS145-47 AIEE NFPA or NFBU No. 70 ' *** Also designated A8RB Standard No. 1S-S8. 768 CHAPTER 57 1959 Guide ABBREVIATIONS AND ADDRESSES The Codes and Standards listed in preceding pages of this table can be obtained from the organizations listed in the Reference Column. ACMA ACRMA AFA AFI A.G.A. AGAEM AU AIEE A1HA AIL AMCA ARI ASA AS of A ASHAE ASHVE ASME ASRE ASTM BCMI BCR BOCA BS CSD CMA CTI FHA GAMA HCCMA HI HP & ACCNA IBR 1CHAM IMFI MWl IUHA MCAA NAFM NBFU NEMA NFPA NHA NRC NWAH & ACA OBI OHIA OPA PC PFMA PHMI REMA RMA SAE SBI SMA TEMA UL USDA USPHS Air Conditioning Manufacturers Association, superseded 1940 by ACRMA. Air Conditioning and Refrigerating Machinery Association, Southern Bldg., Washington, D. C- superseded 1953 by ARI. American Foundryroen's Association, 616 S. Michigan Ave., Chicago, 111. Air Filter Institute, 3 Center Park, Rochester 3, N. Y. American Gas Association, 420 Lexington Ave-, New York 17, N. Y. Association of Gas Appliance and Equipment Manufacturers, superseded 1945 by GAMA. American Institute of Architects, 1741 New York Ave., N. W., Washington 6, D. C. American Institute of Electrical Engineers, 33 West 39th St., New York 18, N. Y. American Industrial Hygiene Association, 14125 Prevost, Detroit 27, Mich. . . Anthracite Industries Laboratory, 237 Old River Rd., Wilkes-Barre, Pa. Air Moving and Conditioning Association, 2159 Guardian Building, Detroit 26, Mich. Air-Conditioning and Refrigeration Institute, 1346 Connecticut Ave., N. W. Washington, D. C. American Standards Association, 70 East 45th St., New York 17, N. Y. Acoustical Society of America, 57 East 55th St., New York 22, N. Y. American Society of Heating and Air-Conditioning Engineers, 62 Worth St., New York 13, N. Y. American Society of Heating and Ventilating Engineers, name changed to American Society of Heating and Air-Conditioning Engineers, Dec. 8, 1954. American Society of Mechanical Engineers, 29 West 39th St., New York 18, N. Y. American Society of Refrigerating Engineers, 234 Fifth Ave., New York 1, N. Y. American Society for Testing Materials, 1916 Race St., Philadelphia 3, Pa. Blast Coil Manufacturers Institute,- superseded by Heating and Cooling Coil Manufacturers Association HCCMA. Bituminous Coal Research) Inc., 121 Meyran Ave., Pittsburgh 13, Pa. Building Officials Conference of America, 110 East 42nd St., New York 17, N. Y. National Bureau of Standards, Washington, D. C. . Commodity Standards Division, U. S. Dept, of Commerce, Washington, D. C. Convector Manufacturers Association, 2159 Guardian Bldg., Detroit 28, Mich. Cooling Tower Institute, 444 Emerson St., Palo Alto, Calif. Federal Housing Administration, Washington, D. C. Gas Appliance Manufacturers' Association, 60 East 42nd St., New York 17, N.' Y. Heating and Cooling Coil Manufacturers Association, superseded by Air Moving and Conditioning Associa tion, AMCA. . Hydraulic Institute, 122 East 42nd St., New York 17, N. Y. . Heating, Piping and Air Conditioning Contractors National Association, superseded. 1956 by Mechanical Con tractors Association of America, MCAA. Institute of Boiler and Radiator Manufacturers, 608 Fifth Ave., New York 20, N. Y. Institute of Cooking and Heating Appliance Manufacturers, Shoreham Hotel, Washington, D. C. Industrial Mineral Fiber Institute, 441 Lexington Ave., New York 17, N. Y. Industrial Mineral Wool Institute, superseded 1953 by IMFI. Industrial Unit Heater Association, superseded 1956 by Air Moving and Conditioning Association, AMCA. Mechanical Contractors Association of America, Suite 570, 45 Rockefeller Plasa, New York 20, N. Y. National Association of Fan Manufacturers, superseded 1956 by Air Moving and Conditioning Association, AMCA. .National Board of Fire Underwriters, 85 John St., New York 33, N. Y. National Electrical Manufacturers Association, 155 East 44th St., New York.17, N. Y. National Fire Protection Association, 60 Batterymarch St., Boston 10, Mass. National Housing Agency, Washington, D. C. National Research Council, 2101 Constitution Ave., Washington, D. C. National Warm Air Heating and Air Conditioning Association, 640 Engineers Bldg., Cleveland 14, Ohio. Oil Burner Institute, superseded 1942 by OHIA Oil Heat Institute of America, Room 1618 (Lower Level) 500 Fifth Ave., New York 36, N. Y. Office of Price Administration, Washington, D. C. Producers Council, 2029 K 8t., N.W., Washington 6, D. C. Propeller Fan Manufacturers Association. Became Power Fan Manufacturers Association before merger with AMCA. Prefabricated Home Manufacturers Institute, 908 20th St., N.W., Washington 6, D. C. Refrigeration Equipment Manufacturers Association, superseded 1953 by ARI. Refrigerating Machinery Association. See ACRMA. Society of Automotive Engineers, 29 West 39th St., New York 18, N. Y. Steel Boiler Institute, 1308 Land Title Bldg., Philadelphia 10, Pa. Stoker Manufacturers Association, 307 N. Michigan Ave., Chicago 1, 111. Tubular Exchanger Manufacturers Association, 53 Park Place, New York, N. Y. Underwriters' Laboratories, 207 East Ohio St., Chicago 11, 111. . United States Department of Agriculture, Washington, D. C. -. United States Public Health Service, Washington, D. C. j :- CATALOG DATA SECTION INDEX TO ADVERTISERS PAGE #3 INDEX TO MODERN EQUIPMENT PAGE *7 INSERT SECTION #25 through #60 INSERT SECTION INDEX ANEMOSTAT CORPORATION OF AMERICA............................ ........... CONNOR ENGINEERING CORPORATION.............................................. HAMMOND BRASS WORKS.............................. ................................................ ROY E. ROTH CO., Turbine Pump Division.............................................. TITUS MFG. CORPORATION...!.............................................. .................... *25-28 *29-32 *45-18 *49-60 33 40 VULCAN RADIATOR CO., THE,................................................................ 41-44 CATALOG DATA SECTION INDEX TO ADVERTISERS HEATING VENTILATING AIR CONDITIONING GUIDE, 1959 A A-J MFG. CO., 3601 E. 18 St.f Dept. Y, Kansas City 27, Mo............................................................................ ACME INDUSTRIES, INC., 600 N. Mechanic St., Jackson, Mich........................................................ *64-65 ADDISON PRODUCTS CO., Addison, Mich............... *97 ADSCO DIVISION, YUBA CONSOLIDATED IN DUSTRIES, INC., 20 Milburn St., Buffalo 12, N. Y.................................................................................. *296 AERCO CORP., Paris Are., P. O. Box 248, North- vale, N. J.................................................................... - *581 AEROFIN CORP., 101 Greenway Ave., Syracuse 3, N. Y............................................................ *186-187 AERoVeNT FAN CO., INC., Ash & Blade Sts., - Piqua, Ohio................................................................... *197 AIR A REFRIGERATION CORP., 439 Madison Are., . New York 22, N. Y...................................................... *63 AIR CONTROL PRODUCTS, INC., 657 Center St., Coopersville, Mich....................................................... *238 AIR DEVICES, INC., 185 Madison Are., New York 16, N. Y.............................................................. *155,240-241 AIR DISTRIBUTION PRODUCTS, 116 S. La Brea Ave., Los Angeles 36, Calif....................................... *239 AIR FACTORS, INC., 1624 S. Raymond Are., Mon rovia, Calif.................................................................... *243 AIR FILTER CORP., 4S54G W. Woolworth Ave., Milwaukee 18, Wis....................................................... *156 AIR-MAZE CORP., 25000 Miles Rd., Cleveland 28, Ohio................................................................................. *157 AIRFAN ENGINEERING CO., 7401 Telegraph Bd., Los Angeles 22, Calif.............................::................ *198 AIRFLOOR COMPANY OF CALIFORNIA, INC., 13729 E. Rosecrans Ave., Santa Fe Springs, Calif................................................................................. **13 AIRTHERM MFG. CO., 708 S. Spring Ave., St. Louis 10, Mo.................................................................. *320 ALADDIN HEATING CORP., 1111 West Ave. 137; San Leandro, Calif..................................................... *199 ALCO VALVE CO., 851 Kingsland Ave., St. Louis 5, Mo............................................................................... .... *270 ALDRICH CO., 121 E. Williams St., Wyoming, 111... *337 ALLEN COOLER & VENTILATOR, INC., 704 Woodward, Rochester, Mich.................................... *230 AMERICAN AIR FILTER CO., INC., 673 Central Ave., Louisville 8, Ky.................................... 158-159-160 AMERICAN AIR FILTER CO., INC., HERMAN NELSON DIV., Louisville. Ky............................*128-129 AMERICAN ARTISAN (publication), 6 N. Michigan Ave., Chicago 2, 111..................................................... *467 AMERICAN BRASS CO., THE, Waterbury 20, Conn. ........................................ i.......................................... *150-151 AMERICAN BRASS CO., THE. AMERICAN METAL HOSE DIV.. P. O. Box 791, Waterbury 20, Conn. *149 AMERICAN FLANGE & MFG. CO., INC., 30 Rocke feller Plata, New York, 20 N. Y.............................. *454 AMERICAN FOUNDRY & FURNACE CO., P. O. Box 904, Bloomington, III................................... *104-105 AMERICAN GAS ASSOCIATION, Arkla-Servel... * 100-101 AMERICAN C1LSON1TE CO., Municipal Airport, P. O. Box 15, Salt Lake City, Utah........................ *428 AMERICAN MOISTENING CO., Cleveland, N. C... *70 AMERICAN SOCIETY OF REFRIGERATING EN GINEERS, 234 Fifth Ave., New York 1, N. Y... *460-461 AMERICAN-STANDARD, AMERICAN BLOWER DIV., P. O. Box 58, Roosevelt Park Annex, De troit 32, Mich...................................................*66-67-68-69 AMERICAN-STANDARD, KEWANEE BOILER DIV., 101 Franklin St., Kewanee, 111................................ *338 AMERICAN-STANDARD, PLUMBING & HEATING DIV., AMERICAN RADIATOR & STANDARD SANITARY CORP., New York 18, N. Y........... *318-319 AMERICAN TUBE PRODUCTS, INC., 100 Pulaski St., West Warwick, R. I............................................ *384 AMERICAN WARMING & VENTILATING CO., 1017 Summit St., Toledo 4, Ohio............................ *226 AMERIVENT, A Div. of AMERICAN METAL PROD UCTS CO., INC., 6100 Bandini Blvd., Los Ange les 22, Calif.................................................................... *365 AMMERMAN CO., INC., Stillwater, Minn................ *231 V. D. ANDERSON CO., THE, DIV. OF INTERNA TIONAL BASIC ECONOMY CORP., I960 West 96th St., Cleveland 2, Ohio...............................*404-405 ANEMOSTAT CORPORATION OF AMERICA, 10 East 39th St., New York 16, N. Y....... Insert Section APRIL SHOWERS CO., INC., 5980-88 Sligo Mill Road, N. E., Washington II, D. C......................... *458 ARKLA AIR CONDITIONING CORP., Shannon Bldg., 812 Main St., Little Rock, Ark................ .. *102 ARMSTRONG CORK CO.. Lancaster, Pa.................. *444 ARMSTRONG MACHINE WORKS, 851 Maple St.. Three Rivera, Mich.......... .................................... *71, 356 AUER REGISTER CO., THE. 6610 Clement Ave., Cleveland 5, Ohio........................................................ *246 BABCOCK & WILCOX CO.. THE, 161 East 42nd St., New York 17, N. Y.............................................. *339 BABCOCK & WILCOX CO., THE, Tubular Products Div., Fittings Dept., 3839 W. Burnham St., Milwaukee 46, Wis....................................................... *304 BAHNSON CO., Winston-Salem, N. C........................ *72 BALTIMORE AIRCOIL CO., INC., P. O. Box 7322, Baltimore 27, Md......................................................... *177 BARBER-COLMAN CO., 1300 Rock St., Rockford. Ill................................................................................*247, 271 BARNEBEY-CHENEY CO., Cassady & 8th Aves., Columbus 19, Ohio..................................................... *161 BAYLEY BLOWER CO., 1821 S. Sixty-Sixth St., Milwaukee 14, Wis....................................................... *200 BELL & .GOSSETT CO.. Morton Grove, 111......... *382-383 BINKS MFG. CO., 3130-36 Carroll Ave., Chicago 12, III................................................... .................................. 178 M. BLAZER & SON, 175Market St., Passaic, N. J... *93 BOILER ENGINEERING * SUPPLY CO., INC., Manarvon St., Phoenixville, Pa............................... *321 G. C. BREIDERT CO., THE, P. O. Box 1190, San Fernando, Calif................................................ .......... *232 BROOKSIDE CORP.. McCordsville. Ind...................... *201 BRYAN STEAM CORP., Chile Pike, Peru, Ind......... *344 BUENSOD-STACEY, INC., 45 West 18th St., New York 11, N. Y................................................................ *73 BUFFALO FORGE CO., 450 Broadway, Buffalo. N. Y. ................................................................................. *202 BUFFALO PUMPS, Div. of BUFFALO FORGE CO., 450 Broadway, Buffalo, N. Y...................................... *394 BURGESS-MANNING CO., 5970 Northwest High way, Chicago 31, III.................................................... *309 BURKE & CO., 2902 Hyde Park Blvd., Los Angeles 43, Calif............................................................................ *162 BURNHAM CORP., Heating & Cooling Div., Irvington-on-Hudson, N. Y.................................................. *324 CAMBRIDGE FILTER CORP., 736 East Erie Blvd., Syracuse 3. N. Y....................................................... *163 E. K. CAMPBELL CO., 1809 Manchester, Kansas City 26, Mo..................................................................... **I6 CAMPBELL HEATING CO., 3121 Dean Ave., Des Moines 17, Iowa.......................................................*114-115 PHILIP CAREY MFG. CO., THE, Lockland, Cin cinnati 15, Ohio...................................................... *446-447 CARLIN CO., THE, 912 Silas Deane Highway, Wethersfield 9, Conn........................;....................... *371 CARNES CORP.. Verona, Wis..................!.............. *248-249 CARRIER CORPORATION, Carrier Pkwy., Syra cuse 1, N. Y.........................................................*74-75, 130 A. W. CASH VALVE MFG. CORP., 666 E. Wabash Ave., Decatur, Hi........................................................ *419 CENTURY FAN & VENTILATOR CO., INC., 45 Cedar St., Stamford, Conn...................................... *203 3 CHAMPION BLOWER & FORGE CO., Div. 9, Lan caster, Pa........................... 1.......................................... #204 CHICAGO BLOWER CORP., 9871 Pacific Ave., Franklin Park, III........................................................ #205 CHICAGO PUMP CO., Subsidiary of FOOD MA CHINERY & CHEMICAL CORP., 622 Diverse? Parkway, Chicago 14, 111.......................................#396-297 CHICAGO STEEL FURNACE CO., 9326 S. Anthony Ave., Chicago 17, III,..;............................................. #117 CHRYSLER AIRTEMP, Dayton 1, Ohio...................... #98-99 CLARAGE FAN CO., Kalamazoo, Mich...................#76, 206 CLEAVER-BROOKS CO., 498 E. Keefe Ave., Mil waukee 12, Wis......................................................... #340-341 COAL-HEAT (publication), 20 W. Jackson Blvd., Chicago 4, 111................................................................. #462 COLT VENTILATION OF AMERICA, INC., 4652 Hollywood Blvd., Los Angeles 27, Calif.... #228-229 COLUMBIA BOILER COMPANY OF POTTSTOWN, Pottstown, Pa..........................................................#342-343 COMBUSTION CONTROL DIV., ELECTRONICS CORPORATION OF AMERICA, One Memorial Drive, Cambridge 42, Moss........................................ #294 CONNOR ENGINEERING CORP., Danbury Conn. ...................................................................... Insert Section CONTINENTAL AIR FILTERS, INC., P. O. Box 1647, Louisville 1, Ky.................................................. #164 COPPER & BRASS RESEARCH ASSOCIATION, 420 Lexington Ave., New York 17, N. Y....................... #154 CRANE CO., 836 S. Michigan Ave., Chicago 5, III. .......................................................................................#322-323 CURTIS MFG. CO., Refrigeration Div., 1959 Kien- len Ave., St. Louis 20, Mo......................................... #193 CYCLOTHERM DIV., NATIONAL-U. S. RADIATOR CORP., Oswego, N. Y................................................. #345 D DAVIS ENGINEERING CORP., 30 Rockefeller Plaza, New York 20, N. Y.......................................... #385 DE BOTHEZAT FANS DIV., AMERICAN MACHINE & METALS, INC., East Moline, 111........................ #207 CHARLES DEMUTH & SONS, INC., 245 Elm Place. Mineola, N. Y....................................................... . #254 DESOMATIC PRODUCTS, INC., 1109 W. Broad St., Falls Church, Va.......................................................... #77 DOLE REFRIGERATING CO.. 5918 N. Pulaski Rd., Chicago 46, III..-............................................................ #194 DOLE VALVE CO., THE, 6201 Oakton St., Morton Grove, (Chicago Suburb), III................................... #420 DOLLINGER CORP., 6 Centre Pk., Rochester 3, N. Y............................ #165 DOMESTIC ENGINEERING CO., (publication), 1801 Prairie Ave., Chicago 16, 111............................ #463 DOMESTIC PUMP & MFG. CORP., Shippensburg, Pa....................................................................................... #395 DOW CHEMICAL CO., THE. Plastic Sales, Mid land, Mich...................................................................... #445 DRAVO CORP., Neville Island, Pittsburgh 30, Pa. ........................................................................................... #118 DRAYER-HANSON, Div. of NATIONAL-U. S. RA DIATOR CORP., 3301 Medford St., Los Angeles 63, Calif........................................................................... 078 DRYOMATIC CORP., 806 N. Fairfax St., Alexan dria, Va............................................................................ #79 DUNHAM-BUSH, INC.. West Hartford 10, Conn. ........................................................................ #406-407-408-409 DURANT INSULATED PIPE CO., Demeter St. off Bay Road, Palo Alto, Calif................................. #429 DURA-VENT CORP., Affiliate of PEERLESS MFG. DIV. of DOVER CORP., 1400 W. Ormsby Ave., Louisville 1, Ky............................................................ #368 DURO-DYNE CORP., Fanningdale, L. I., N. Y... #266-267 E ELECTRO-AIR CLEANER CO., INC., Olivia & Sprout Sts., McKees Rocks, Pa............................... #166 ELECTROMODE, Div. of COMMERCIAL CON TROLS CORP., Rochester 3. N. Y......................... #144 ELGO SHUTTER & MFG. CO., 2378 W. Warren, Detroit 8, Mich.............................................................. #227 ENTERPRISE ENGINE & MACHINERY CO., A Subsidiary of GENERAL METALS CORP., 18tfa and Florida Sts., San Francisco 10, Calif...... #372 GEORGE EVANS CORP., THE, 121 37th St., Moline, 111....................................................................................... #167 F FAIRBANKS CO., THE, 393 Lafayette St.. New York 3, N. Y............................... #421 FANJET DIV., MUELLERMIST IRRIGATION CO., 2616 S. Ninth Ave., Maywood, HI.,........................ #459 FARR CO., P. O. Bo* 45187, Airport Sta., Los An geles 45, Calif........................................................... #168-169 FEDDERS CORP., Laior & Hancock Sts., Tren ton 7, N. J....................................................................... #J3i FEDERAL BOILER CO., INC., Midland Park, N. J. f5 AIR CONDITIONING CORPi, 1815 Si MaybeVlej Tulsa, Okla................................................................. #80 FIELD CONTROL DIV., H. D. CONKEY & CO., Press Bldg., Mendota, III..................................... #292-293 FITZGIBBONS BOILER CO., INC., 101 Park Ave., New York 17, N. Y....................................................... #347 FLEXON1CS CORP-, Expansion Joint Div., 1329 S. Third Ave., Maywood, III.......................................... #297 FLUOR PRODUCTS CO., A Div. of THE FLUOR CORP., LTD., 12000 E. Washington Blvd., Whit- . tier, Calif........................................................................ #179 FRICK CO., Waynesboro, Pa.......................................... #195 G G & O MFG. CO., THE, 140 Winchester Ave., New Haven 8, Conn.............................................................. #190 GARDEN CITY FAN CO., 801 North 8th St., NUes, Mich...................................................... . , #208 GENERAL AUTOMATIC PRODUCTS CORP., 2300 Sinclair Lane, Baltimore 13, Md............................ #310 GENERAL BLOWER CO., 8602 Ferris Ave., Morton Grove, HI........................................................................ #209 GENERAL CHEMICAL DIV., ALLIED CHEMICAL CORP., 40 Rector St., New York 6, N. Y............. #81 GENERAL CONTROLS, 801 Allen Ave., Glendale 1, Calif............................................................................ #272-273 GENERAL ELECTRIC, Air Conditioning Dept., Tyler, Texas..................................................................#82-83 GENERAL FITTINGS CO., Box 1S1K, East Green wich, R. I........................................................................ #386 GENERAL SOUND CONTROL, INC., 6711 S. Sepul veda Blvd., Los Angeles 45, Calif........................... #433 E. D. COODFELLOW CO., INC., 496 E. Bodiey Ave., Memphis, Tenn............................................................ #180 B. F. GOODRICH, A Div. of THE B. F. GOODRICH CO., 574 Derby Place, Shelton, Conn................... #448 GORDON & PIATT, INC., P. O. Box 914, Winfield, Kans....-.......................................................................... #369 COVERNAIR CORP., 4840 N. Sewell, Oklahoma City 4, Okla.................................................................... #84 GUSTIN-BACON MFG. CO., 206 West 10th St., Kansas City, Mo........................................................... #434 H HAGAN MFG. CO., Delphos, Ohio................................ #449 HAMMOND BRASS WORKS, Summer Blvd., Ham mond, Ind................................................. # Insert Section ELOF HANSSON, INC., 711 Third Ave., New York IT. N. Y............................................................................ #435 ARTHUR HARRIS & CO., 210-218 N. Aberdeen St., Chicago 7, III....................................................... #308 HART & COOLEY MFG. CO., Holland, Mich. .. #250-251 HAVENS COOLING TOWERS, Div. of HAVENS STRUCTURAL STEEL CO., 1713 Crystal, Kan sas City, Mo................................................................... # 181 HAYES FURNACE MFG. & SUPPLY CO., 3233 S. La Cienega Blvd., Los Angeles 16, Calif.. ... 106-107 HEATING & AIR CONDITIONING CONTRACTOR, (publication, formerly SHEET METAL WORKER), 92 Martling Ave., Tarrytown, N. Y. ............................................................................................ #468 HEATING, PIPING & AIR CONDITIONING (pub lication), 6 N. Michigan Ave., Chicago 2, III... #467 HEATING PUBLISHERS, INC., 2 West 45th St., New York 36, N. Y..................................................... #464 HENDRICK MFG. CO,, 48 Dundoff St., Carbondale, Pa............................... . .. #252-253 HENRY VALVE CO., 3215 North Ave., Melrose Park, HI........................................................................... #274 HIRSCHMAN-POHLE CO.. INC., 200 Lent Ave., Le Roy, N. Y.............................................. ... . #233 HOFFMAN SPECIALTY MFG. CORP., 1700 West 10th St.. Indianapolis 7, Ind.............................. #410-411 HYDROTHERM. INC., Northvale, N. J...................... #348 I . 1LG ELECTRIC VENTILATING CO., 2880 N. Pu laski Road, Chicago 41, III.................................#134, 214 ILLINOIS ENGINEERING CO., Div. of AMERICAN AIR FILTER CO-, INC., 2059 S. Racine Ave., . Chicago 8, HI................................................................. #418 ILLINOIS TESTING LABORATORIES, INC., Room 516, 420 N. LaSalle St., Chicago 10. 111............. #275 4 INDEPENDENT REGISTER CO., THE, 3747 East 93rd St., Cleveland 5, Ohio....................................... #255 INDUSTRIAL ACOUSTICS CO., INC., 341 Jackson Ave.. New York 54, N. Y............................................ #436 INDUSTRIAL COMBUSTION, INC., 4507 N. Oak land Ave., Milwaukee 11, Wis..................................... #373 INDUSTRIAL ENGINEERING & EQUIPMENT CO., 22 Hanley Industrial Ct., St. Louis (Brent wood) 17. Mo........ ......................... . ......................... #145 INDUSTRIAL PRESS, THE, 93 Worth St., New York 13, N. Y............................................................................ #666 INFRA INSULATION, INC., 525 Broadway, New York 12. N. Y.......................................................... ^SS INTERNATIONAL BOILER WORKS CO., THE, 500 Birch St., East Stroudsburg, Pa.......................... #349 INTERNATIONAL EXPOSITION CO., 480 Lexing ton Ave.. New York 17, N. Y.................................... #465 J JACKSON * CHURCH, Div. of YORK-SHIPLEY, INC., York, Pa.............................................................. #119 JENKINS BROS., 100 Park Ave., New York 17, N. Y. JENN-A1R PRODUCTS CO., INC., 1108 Stadium Drive, Indianapolis 7, Ind........................................ #234 JOHNS-MANSVILCE, 22 East 40th St., New York 16, N. Y....................................................................... #450-451 S T. JOHNSON CO., 940 Arlington Ave., Oakland 8, Calif.......................................................................#374-375 JOHNSON HEATER CORP., 1 Winnisimmet St., Chelsea, Mass.......................................................... # 120-121 JOHNSON SERVICE CO., 507 E. Michigan St., Milwaukee 1, Wis.....................................................#276-277 JOHNSTON BROS., INC., Ferrysburg, Mich'... #350 JOURNAL of PLUMBING, HEATING & AIR CON DITIONING, THE, (publication) 92 Martling Ave., Tarrytown, N. Y................................................ #468 JOY MFG. CO., General Offices, Henry W. Oliver Bldg., Pittsburgh 22, Pa..................................... #210-211 K KEENEY PUBLISHING CO., 6 N. Michigan Ave., Chicago 2, III..............................................:................ #467 KENNARD DIV. of AMERICAN AIR FILTER CO., INC., 1270 N. Price Rd., St. Louis 14, Mo........... #85 KILLEBREW ENGINEERING CORP., 8640 Pardee Lane, St. Louis 23, Mo................................................. #387 KOPPERS CO., INC., Metal Products Div., Balti more 3, Md...................................................................... #437 KRAISSL CO., INC., THE, 297 Williams Ave., Hackensack, N. J............................. . -. -................... #400 KRITZER PRODUCTS, A Div. of PEERLESS OF AMERICA. INC., 5800 Pulaski Rd., Chicago 46, in............................................................................................... #103 KRITZER RADIANT COILS, INC., 323 N. River St., Batavia, 111.............................................. KRUEGER AIR CONDITIONING CORP., 19 E. Rillito, Tucson, Ariz.................................................... #256 L L0`F GLASS FIBERS CO., Dept. 19-118, 1810 Ma dison Ave., Toledo 1, Ohio...................................#438-439 LADISH CO., Cudahy, Wis.. ,......................................... #305 LARCO, INC., Route 20 East. Painesville, Ohio.. #108 LAU BLOWER CO., THE, 2027 Home Ave., Dept. J., Dayton 7, Ohio.........................................................#212--213 LENNOX INDUSTRIES INC., 1701 E. Euclid, Des Moines 4, Iowa............................................................. # 122 LENNOX INDUSTRIES INC., Marshalltown, Iowa .................... :............... .................................................... #109 LESLIE CO., 237 Grant Ave., Lyndhurst, N. J....... #278 LIL1E-HOFFMANN COOLING TOWERS, INC., 1450 S. Vandeventer Ave., St. Louis 10, Mo............... #182 LOCKPORT MILLS, INC., Dept. C. Lockport, N. Y. ........................................................................................... #452 M MAID-O'-MIST, INC., 3217 N. Pulaski Rd., Chi cago 41, III................................ .............................. #412-413 MAJESTIC CO., INC., TIIE, Erie St-, Huntington, Ind..................................................................................... #110 MAMMOTH FURNACE CO., THE, 6425 Cambridge St., Minneapolis 26, Minn....................................... 123 MARLEY CO., THE, 222 W. Gregory, Kansas City 13, Mo................................................................................ #183 MARLO COIL CO., 7100 S. Grand Blvd., St. Louis 11. Mo.............................................................................. #86 JAS. P. MARSH CORP., Dept. 5, Skokie, 111............. #423 MAXITROL CO., 12200 Beech Rd., Detroit 39, Mich.................................................................................... 279 McDONNELL & MILLER, INC., SSOO N. Spaulding Ave., Chicago 18, III..............................................#358-359 McQUAY, INC., 1602 Broadway, N. E., Minneapolis 13, Minn...................................................................... #132-133 MERCOID CORP., THE, 4201 Belmont Ave., Chi cago 41, III...................................................................... #280 METTLER CO., INC., THE, Div. of ECLIPSE FUEL ENGINEERING CO., Rockford, III........................ #376 METALBESTOS DIV., WILLIAM WALLACE CO., . Belmont, Calif..........................................................#366-367 MINNEAPOLIS-HONEYWELL REGULATOR CO., 2644 Fourth Ave. So., Minneapolis 8, Minn. .................................................................... J.............#170,281 MOELLER INSTRUMENT CO., 132nd St. and 89th Ave., Richmond Hill 18, N. Y.................................. #282 MONARCH MFG. WORKS. INC., 2509 E. Ontario St., Philadelphia 34, Pa............................................. #185 MUCKLE MFG. CO., 666 Belford Road, Owatonna, Minn................................................................. #235 MUELLER BRASS CO., Port Huron 12, Mich........ #424 MUELLER STEAM SPECIALTY CO., INC., 29 Meserole Ave., Brooklyn 22,N. Y............................ #357 D. J. MURRAY MFG. CO., Wausau, Wis................... #135 N NASH ENGINEERING CO., THE. 234 Wilson Rd., South Norwalk, Conn............................................ #398-399 NATIONAL CLAY PIPE MFRS., INC., 1820 "N" St. N. W., Washington 6, D. C...............#314-315-316-317 NATIONAL HEATER CO., INC., 2475 Doswcll Ave., St. Paul 4, Minn...................................................... #124-125 NATIONAL-U. S- RADIATOR CORP., Johnstown, Pa.......................................................................... #325-326-327 HERMAN NELSON, AMERICAN AIR FILTER CO., INC., Louisville, Ky............................................... #128-129 JOHN J. NESBITT, INC., State Road & Rhawn St., Philadelphia 36, Pa............................................. #142 NEW YORK BLOWER CO., THE, 3171 S. Shields Ave., Chicago 16, 111.................................................... #215 NIAGARA BLOWER CO., 405 Lexington Ave., New York 17, N. Y................................................................. #87 O ORR & SEMBOWER, INC., Morgantown Rd., Read ing, Pa.............................................................................. #351 OWENS-CORNING FIBERGLAS CORP., Toledo 1, Ohio........................................................................... #171, 440 OWENS-ILLINOIS, General Offices, Toledo 1, Ohio ........................................................................................... #441 P PACIFIC STEEL BOILER DIV., NATIONAL-U. S. RADIATOR CORP., Johnstown, Pa..................#328-329 PA#R3K1S1-CRAMER CO.. Fitchburg, Mass..................... #88 PATTERSON-KELLEY CO.. INC., THE, 101 Burton St., East Stroudsburg, Pa......................................... #191 PEERLESS ELECTRIC CO., THE, 1402 W. Market St., Warren, Ohio........................................................ #216 PEERLESS HEATER CO., THE, Boyertown, Pa. .................................................................................... #330-331 PEERLESS PUMP DIV., FOOD MACHINERY & CHEMICAL CORP., 301 West Ave. 26, Los An geles 31, Calif................................................................ #401 PENN CONTROLS, INC., Goshen, Ind....................... #283 PENN VENTILATOR CO., Goodman above Alle gheny Ave., Philadelphia 40, Pa............................. #236 PENNSYLVANIA FURNACE & IRON CO., 316 N. Pine St., Warren, Pa............................................ 111, 332 PETRO, 3242 West 106th St., Cleveland 11, Ohio .................................................... #378-379 PHILLIPS COOLING TOWER CO., INC., 220 Dupont St., Brooklyn 22, N. Y................................................ #184 PIPE LINE DEVELOPMENT CO., THE, 5700 De troit Ave., Cleveland 2, Ohio.................................. #306 PITTSBURGH CORNING CORP., Dept. S-9, One Gateway Center, Pittsburgh 22, Pa....................... #442 PITTSBURGH LECTRODRYER DIV., McGRAW- EDISON CO., P. O. Box 1766, Pittsburgh 30, Pa....................................................................................... #89 PITTSBURGH PLATE GLASS CO., Fiber Glass Div., I Gateway Center, Pittsburgh 22, Pa. .............................................................................. . #172, 443 H. W. PORTER & CO., INC., 817-G Frelinghuysen Ave., Newark 12, N. J.................................................. #430 POWERS REGULATOR CO., THE. General Office and Factory, $400 Oakton St., Skokie 84, 111. .................................................................................... #284-285 PROPELLAIR DIV., ROBBINS A MYERS, INC., 1359 Stone Bird., Springfield, Ohio....................... #217 PYLE-NATIONAL CO.. THE, Multi-Vent Dir., 1363-78 N. Kostner Are.. Chicago51, 111............... 25? R TiUVJBuEu TaURNS, uDair.. mof*CHimEMimEaTRON' wCO*R**P.,.,uLwomu.i-s-- . rille 1, Ky....................................................................... *307 TUTHILL PUMP CO., 979 East 9Sth St., Chicago 19, IU....................................................................................... *403 TUTTLE A BAILEY, New Britain, Conn.............. 258-259 RANCO, INC., Columbus 1, Ohio.................................. 288 U. RAY BURNER CO., 1301 San Jose Ave.. San Fran cisco 12, Calif................................................................ #377 RAYPAK CO., INC., 2416 Chico Are., El Monte, Calif.................................................................................. *352 READING TUBE CORP., Empire State Bldg., New York 1, N. Y.............................................................. 188-189 READY-POWER CO., THE, 11231 Freud Are., Detroit 14, Mich........................................................... 196 RECOLD CORP., 7250 E. Slauaon Arc., Los Angeles 22, Calif..........................................................................*90-91 REED UNIT-FANS, INC., SOI N. St. Patrick St., New Orleans 19, La................................................ *218 REFLECTAL CORP., A Subsidiary of BORG-WAR- U. S. FLEXIBLE METALLIC TUBING CO., KE FLEX MFG. DIV., 63 Main St., San Francisco 5, Calif............................................... 298-299-300-301-302-303 UNITED SHEET METAL CO.. INC., 540 S. Drexel Are., Columbus 9, Ohio............................................. *268 UNITED STATES REGISTER CO., Battle Creek, Mich.............................................................................260-261 UNIVERSAL DIFFUSER CORP., 38 Marbledale Rd., Tuekahoe, N. Y...................... 264 UTILITY FAN CORP., A Dir. of UTILITY APPLI ANCE CORP., 911 East 59 St.. Los Angeles 1, Calif................................................................................. *113 NER CORP., 200 S. Michigan Are., Chicago 4, HI................................................................................ *453, 456 REFRIGERATION APPLIANCES, INC., 909 West VAPOR HEATING CORP., 80 E. Jackson Blvd., Lake St., Chicago 7, 111.............................................. *112 Chicago 4, 111................................................................. *354 RESEARCH PRODUCTS CORP., Madison 1, Wis. .............................................................................................. m VIKING AIR PRODUCTS, 5601 Walworth Are., Cleveland 2, Ohio........................................................ *223 REVCOR, INC., 251 Edwards St., Carpentersrille, 111....................................................................................... 219 RIC-WIL INC-, 24 Brown St., Barberton, Ohio.. 431 VORTOX CO., Claremont, Calif.................................... *175 VULCAN RADIATOR CO., THE, 775 Capitol Are., Hartford 6, Conn.................................... Insert Section RICHMOND ENGINEERING CO., INC., 7th & Hospital Sts., Richmond 19, Va.............'............... *388 RITTLING CORP., THE, 103 Kentucky St., Buffalo 5, N. Y......................................................... #192 ROBERTSHAW-FULTON CONTROLS CO., FUL- TON-SYLPHON DIV.. Knoxville 1, Tenn.... *286-287 H. H. ROBERTSON CO., 2400 Farmers Bank Bldg., Pittsburgh 22, Pa............................................................ *92 ROY E. ROTH CO.,Milan, III.................Insert Section WALTON LABORATORIES, INC., 1186 Grove St., Irvington 11, N. J....................................................... 94 WATERLOO REGISTER CO., INC., P. O. Box 72, Waterloo, Iowa............................................................. *265 WATTS REGULATOR CO., 10 Embankment St., Lawrence, Mass........................................................*426-427 WARREN WEBSTER & CO., 1731 Federal St., Cam S SARCO CO.. INC., 635 Madison Are., New York 22, N. Y..............................................................................414-415 SCOTT-CHOATE PUBLICATIONS, 92 Martling Arc., Tarrytown, N. Y................................................ *468 SHAW-PERKINS MFG. CO., 201 E. Carson St., Pittsburgh 19, Pa................ ^................................... *312 SHELDONS ENGINEERING LTD., Galt, Ontario, Canada ........................................ *220 SIMPLEX MFG. CO.. 198-206 N. Main St., Fond du Lac, Wis........................................................................... *295 SKIDMORE CORP., St. Joseph, Mich........ ............... 402 H. B. SMITH CO., INC., THE, Westfield. Mass... *333 SNIPS MAGAZINE (publication), 5707 W. Lake St., Chicago 44, HI....................................................... *469 SONNER BURNER CO., TIIE, P. O. Box 903, 412 420 East Sixth St., .Winfield, Kans...................... *370 SONOCO PRODUCTS CO., Construction Products Div., Hartsrille, S. C.............'.................................... *364 SPENCE ENGINEERING CO., INC., 31 Grant St., Walden, N. Y................................................................. 289 SPENCER HEATER, LYCOMING DIVISION-AVCO MFG. CORP., Williamsport, Pa......................... *334-335 STERLING, INC., 5208 W. Clinton Are., Milwau kee 18, Wis...................................... .............................. *389 STRONG, CARLISLE A HAMMOND, 508 Sandusky St., Conneaut, Ohio........ ........................................ 425 den 5, N. J................................................................. 416-417 WEIL-McLAIN CO., General Sales Office, Michi gan City. Ind....................................................................*336 WESIX ELECTRIC HEATER CO., 390 First St., San Franeiseo 5, Calif............................................... 148 WESTERN BLOWER CO.. 1800 Airport Way, Seattle 4, Wash............................................................................ 224 WESTERN BOILER CO:, 1600 N. Indiana St., Los Angeles 63, Calif................... *355 WESTERN ENGINEERING A MFG. CO., 4112 Glencoe Are., Venice, Calif............................... .. *237 WESTINGHOUSE ELECTRIC CORP., STURTE- VANT DIV., Hyde Park, Boston 36, Mass. . 176, 225. WHITE-RODGERS CO.. 1209 Cass Arc., St; Louis 6, Mo................................................................................ *290 WHITTY CO., INC., 86 Western Are., Boston 34, Mass................................................................................. *361 EDWIN L. WIEGAND CO., 7672 Thomas Bird., Pittsburgh 8, Pa................. .................................. 146-147 WILCOLATOR CO., THE, 1001 Newark Are., Eliza beth, N. J.................................................-.................... 291 WILL-BURT CO.. THE, Orrrille, Ohio.................*362-363 WILSON ENGINEERING CORP., 6 N. Michigan Are., Dept. II659, Chicago 2, U1.......................... *360 L. J. WING MFG. CO., Dir. of AERO SUPPLY MFG. CO., INC., 59 Vreeland Mills Road, Lin den, N. J.................................................................... 140-141 W1REMOLD CO.. THE,Hartford 10,Conn............. *269 .T ' WOLVERINE TUBE, 17286 Southfield Road, Allen Park, Mich.................................................................152-153 TACO HEATERS, INC., 1160 Cranston St., Crans WOOD CONVERSION CO., Dept. 220-9, First Na ton 9, R. I....................................................................... 392 tional Bank Bldg., St. Paull, Minn....................... *457 THERMOBLOC DIV., PRAT-DANIEL CORP., 2 , : WORTHINGTON CORP., Air Conditioning * Re Meadow St., South Norwalk, Conn...................... *126 frigeration Dir., Ampere Station, East Orange, THERMOTANK, INC.. 11191 Lappin Are., Detroit N. J........................... ..................................................... 95 34, Mich........................................................................... *242 H. A. THRUSH A CO., Peru, Ind........................... 390-391 TITUS MFG. CORP., 113 East 8th St., Waterloo, Iowa............................................................ Insert Section ,Y YORK CORP., Subsidiary of BORG-WARNER TITUSVILLE IRON WORKS CO., THE, Dir. of STRUTHERS WELLS CORP., Titusville, Pa.... *353 TJERNLUND MFG. CO., 2140 Kasota Are., St. Paul 14, Minn..................... *127 TORRINGTON MFG. CO., THE, 50 Franklin St.. Torrington, Conn......................................................... *221 TRADE-WIND MOTORFANS, INC., 7755 Para CORP., York, Pa.................................................... *96 YORK-SHIPLEY, INC.,York 16, Pa........................ *380 YOUNG RADIATOR CO., Dept. 549, Racine, Wis. ................................................. *143 YOUNG REGULATOR CO., 20910 Miles Are., Cleve land 28, Ohio.............................. . . . ................. *262-263 YULA CORP., formerly YULA WATER HEATERS, mount Bird., Rivera, Calif...................................... *222 INC., 330 Bryant Are., New York 59, N. Y........... S93 TRANE CO., THE, 2021 Cameron Are., LaCrosse, Wis................................................................. *136-137-138-139 TRION, INC., 1000 Island Are., McKees Rocks, Pa. Z ....................................................................................................... *174G. S. ZIEGLER* CO., Great Neck, N. Y.....J........ 432 . INDEX TO MODERN EQUIPMENT OF ADVERTISERS APPEARING IN Heating Ventilating Air Conditioning Guide 1959 ACCUMULATORS ,,,, Americas Tube Products, lac., -384 Dale Refrigerating Co-. -194 Domestic Pump A 1U|. Corp., *385 Worthington Core., Air Conditioning A - - - jfcn Dir., -85. AIR CONDITIONING COILS Acme Industries, 1m., *84-65 Addison Products Co., <97 . Airtemp Dir., Chrysler Corp., *88-69 ACOUSTICAL CONTROL ' General 8ound Control, loo.. *49 Elot 1m., *41S Industrial Acoustics Co., Inc., *438 Muu-HuTille, ,450 ill . American Blower Dir. of AmericanStandard, -86-69 Bell A Goasett Co., -5S3-S83 M. Blaser A Boo., *93 - Carrier Corporation, *74-75, (30 Koppera Co., Inc., Metal Product* Div., darage Fan Co., *78,306 Crane Co., *323-333 nryi.Hi>ini' Div. of National-U. 8. Radiator Corp.. *78 - Dunham-Bush, Ino., *408-109 . United Sheet Metal Co., *368 f5 Air Conditioning Corp., -80 General Electric Co.. *82-63 ADHESIVES - Covernair Corp.. *84 Armstrong Cork Co., *444 Duro-Dyne Corp., *186-267 Kennard Div., American Air FBtm Co-, Inc.. *8S - Kritser Products, A Div. of Pecrttse of ADSORBERS. Odor Baraebey-Cheney Co,, -161 . America, Ino., *103 larco, Inc., -108 Connor engineering Carp., -Insert See- l*"-- Industries, Inc., -108, 133 Mario Coil Co.. McQuay, Ino.. *133-133 ADSORPTION SYSTEMS John J. Nesbitt, Inc., *143 Arkle AirConditioningCarp., -103 Niagara Blower Co., *87 1 . Bamebcy-Cheney Co-, -181 Patterson-Kelley Co., Inc., The, *191. Connor Engineering Corp., -Insert Sec Recotd Corporation, *90-91 tion Refrigeration Appliances. Inc., *113 Dmomatic Products, Inc., >77 Trans Co., The. *138-139 Dryomatie Corp., -79 Worthington Corp-, Air Conditioning A Pittsburgh Lectrodryer Div., McGraw- Refrigeration Div., *95 ' Co., *69 - York Corp., Sub. Borg-Warner Carp-, *96 Young Radiator Co., *143 . AFTER COOLERS Joy Manufacturing Co., (SUMII . Niagara Blower Co., *87 ' Wilson Engineering Corp-. *380 AIR CONDITIONING COMPRES SION EQUIPMENT Airtemp Div., Chrysler Corp., *98-99 American Blower, Div. of Amcrican- AIR CLEANING EQUIPMENT (Sot atto PHUtx, Air) Air A Refrigeration Corp., *83 Air Devices, Ino., *155, 340-341 Ab Filter Corp.,.156 . . Frick Co., *195 Air-Mats Corp., The. *157 General Electric Co., *83-83 . American Air Filter Co., Inc- -158-150 Trane Co., Tbs, *118-139 Amman Blower, Dir. of American,--' Worthington Con., Air Conditioning A Refrigeration Div., -95 York Corp., Sob. Borg-Wamer Corp., *96 Beroebey-Chenry Co., *161 Burks A Co., .163 . Cambridge Filter Corp., *163 C,,toionnoor Engineering Corp-., .Insert Seo- Continental Air Filters, Inc., *164 Dollinga Corp., *165 Kleetro-Air Cleaner Co.. Inc., *166 Qeorge Evans Corp., The, *167 Farr Co., *168-169 General Electrie Co.. *83-83 Jay Mfg. Co., OJO-Jll - Iiwnnox Industries, Ino., *109, 133 Minneapolis-Honeywell Regulator Co., 170.381 . . Owens-Corniag Fiberglai Corp., *171, 440 Pittsburgh Plate Glass Co., Fiber Glam Div., *172.443 Wcwnnh Products Corp., *173 Trim, Inc., *174 Vertex Co., *175 . Westingbouse Electric Corp., Sturtevsn* Div., *178, 335 AIR CONDITIONING CONTROLS. (Set Controller* cad Control Sgulpmext, Electric, Humidify cad Temperature Centrals) AIR CONDITIONING. Refrigerants General Chemical Div., Allied Chemical Corp., -81 - AIR CONDITIONING REGISTERS AND GRILLES CSw OrOUi, Berk un) . AIR CONDITIONING UNITS Acme Industries, Inc., -64-65 Addison Products Co., *97 Air A Refrigeration Corp., *63 Airtemp Div., Chryals Corp., *98-99 I' American-Standard Plumbing A Heat ing Div., *318-319 Anemostat Corporation of America, Insert Section Arida Air Conditioning Corp., *183 Betl A Gossett Co., -582-383 M. Biaxer A Son, *93 Buensod-Stacey, Ino., *73 .- Buffalo Forge Co., *303 Burgess-Manning Co., Architectural Products Div., *309 Carrier Corporation, *74-75, 130 Chicago Stem Furnace Co., *117 Clarage Fan Co.. *78, 308 Crane Co., *323-333 ' Curias Ml*. Co., RMiigaatiuu Div., *193 Dole Refrigerating Co., *194 Drayer-Hansan, Div. of National-U. S. Radiator Corp., *78. . Dunham-Bush, lne., *406-408 Etectramode, Div. of Commercial Con trols Corp., *144 f5 Air Conditioning Corp., *88 Farr Co., *168-189 Fodders Corporation, *131 Frick Co.. *195 - General Automatic Products Corp .,*310 General Electric Co., *83-83 Covernair Corp., *84 ' Ilg Eleetrie Ventilating Co.,-*134, 314 S. T. Johnson Co.. *374-875 - Kennard Div. of American Air Filter Co., Inc., *SS Kritser Radiant Coils, Inc., *311 Laroo, Inc..-108 Industries, Inc.. *109, 123 Majestic Co., Inc . The, *110 Mario Coil Co., *88 McQuay. Ino. *133-133 National-U. 8. Radiator Corp., Heating A Air Conditioning Div.. *325-337 . Herman Nelson Div., American Air rdter Co.. Inc.. -138-139 John J. Nesbitt, lne., *142 Niagara Blower Co., *87 Patterson-Kelley Co., lne.. The. *191 reericas Electric Co., The, *316 . Pennsylvania Furnace A Iron Co., *111, 333 Ready Power Co., The, *196 Recold Corporation, -90-91 Refrigeration Appliances, Inc., *113 Rittlmg Corp , The, *192 Thermotank, Inc., *343 Trane Co., The, *138-139 - Vulcan tioa Co., The, *Inswt Sco- Warren Webster A Co., *416-417 WeB-McLain Co., *336 -. Western Blower Co-, *338 ' Worthington Corp., Air Cowditinnlng A Refitecratiort Div., *95 York Corp., Bub- Borg-Warner Carp., -96 York-Shipley, lne., *380 Young Ridiator Co., *163 AIR CONDITIONING UNITS. Con trol, Air Volume Damper Anemostat Corporation of America, Insert 8ection AIR-COOLED CONDENSERS . Acme Industries, Ino., *84-65 M. Blaser A Son, *93 . Drayer-Hanson, Div., National-U. S. Radiator Corp., *78 Duubam-Bush, 1m., -408-409 IS Air Conditioning Corp., *80 Goventatr Corp., -84 , McQuay, Inc., *133-133 . . Refrigeration Applianrra, Inc.. *113 ntlon THE CUIDB 1999 when writing to Advertisers ' AIR COOLING-HUMIDIFYING AND DEHUMIDIFYING AP PARATUS Addison Produets Co.,-97 Engineering Co., *198 Air A Refrigeration Corp., *63 Airtemp Ehy., Chrysler Corp., *98-99 American Blower. Div. of American- Btandard, *68-60 American Moistening Co., *70 Armstrong MaehineWorks, *71,356 Rahnaoa Co., The, *73 Bayley Blows Co., *300 M. Bister A Son, *93 '' Buensod-Stacey, Inc., *73 Buffalo Forge Co.. *303 ' Carrier Corporation. *74-75, 130 Oarage Fan Co., *76, 206 . Curtis Mfg. Co., Refrigeration Div.. 193 - Deaomatic Products, lne., *77 : ' Prayer-Hanson, Div. of National-U. 8. Radiates- Carp., *78 Dryomatie Corp-, *79 Fur Co., -168-169 Frick Co., *195 - General Eleetrie Co., -83-63 Covernair Corp-, *84 - Joy Mfg. Co.. *318-311 ' yin*fit Div. of Aasas Air Filter Co.. Inc.. *65 Kritser Products, A Div. of PcericOT af America, Ino., *103 Lennox Industries, Inc., *109, 123 Msrio Coil Co.. *66 National-U. S. -- Corp., Heating A Air Conditioning Div., *325-327 Niagara Blower Co., -87 . Perks-Cnmer Co., *88 Pittsburgh Lectrodryer Div., McOtswRriivon Co., *89 Recold Corporation, *98-91 Research Products Corp., *173 Thermotank, Inc-. *343 Trane Co., The, *138-139 Walton inberatories, lne., *94 WeB-McLain Co., -336 " Worthington Carp., Air Conditioning A Refrigeration Div., -95 York Corp., Sub. Barg-Warner Corp., *96 AIR DIFFUSER UNITS. High Prcs- Air Devisee, lne., *155. 348-341 American Warming A Ventilating Co.. The, *338 Anemostat Corporation of America, Insert Section ' Auer Rerirtm Co,, -346 Barbcr-Cobnan Co., *247, 371 Connor Engineering Corp., 'Insert Seo- tion ` Tbermotank. Inn., *343 S Tuttle A Bailey, .258-359 . United Btates Register Co,, *380-361 Universl Diffuser Corp., *264 AIR DIFFUSERS AND VENTILA TORS, CEILING, FLOOR AND WALL A-J Mfg- Co.. *346-245 Air Control Products. Im., *238 Air Devices. Inc.. .155, 340-241 Air Distribution Products, *339 Air-Factors, Inc., *343 '' American Worming A Ventilating Co,, The, *228 1959 Guide Auer Register Co-, Tbe, *946 ' Barber-Cwmaa Co, *347, *71 Cans Oorp, 3484(9 Coenor Engineering Carp. Insert Seo- Cbark* Dernuth A Sons, Ine, *384 General Elective Co., *32-63 Hart A Cooley Mfg, Co, JS0-B1 Hendrick Mfg. Co., *288461 Independent Register Co., Tbe, *385 Knunr Ale PMutidewin| Cons* 255 Pyte-Natioosl Co., Tbe. MoUi-Veat Die.. >267 Tbenooteak, loo., *242 Titus Mff. Corp., Insert Section AIR DUCTS (Sm Dud*) AIR ELIMINATORS American Tube Products, Inc, *284 V. D. Astern Co, Tbe, Div. of Inter* national n**** Economy Corp., HOf* 405 Armstrong MiAim Works. *71, 355 _ ni^w*H. Engineering Dir., American Air Filter Co, Inc., *418 Joy Mfi. Co-, *210-211 MaidO'-Mht, Inc, *412-413 Jaa. P. Mareh Corp., *423 Sereo Co.; Inc., *414-418 Tuo Hcattea, ine, *333 . H. A. Thrash A Co, *390-391 AIR FILTER CAGE Air Devises, Ine, .165, 840-341 Owens Coming Fibrnglm* Corp., *171, 440 R--r*h Products Carp., *173 AIR FILTERS (Sm FiZIws, Air; Air AIR MEASURING INDICATING AND RECORDING INSTRU MENTS . Ancmcstat Corporation of Amtria, 170,281 I Escalator Co., AIR PURIFYING APPARATUS Air A Refrigeration Corp., *63 Air Filter Corp., *155 ` Air-Uaxe Carp, *157 - Amerian Air Filter Co, Ioe, >158-160 American Blower, Dir. ot Ammcan- V. D. Anderson Co.. Dr*, of Interna tional Basie Rcnwony Corp., *404405 Barnebey-Cbeney Co.. *161 Connor Enginatnng Corp., *Insert Seo* DoUmger Oorp., *165 Electro-Air CleanerCo., Iso., *106 Joy Mfg. Co., *210-211 ' Lctboi Industries, Inc-1*109. 122 MlnaMMlWHniwyi11 Regulator Co, Trion,* Lne, *174 Universal Diffuser Corp, *204 AIR RECEIVERS (Sm Emsimts. Air) AIR RECOVERY. Method of Bamebey-Cheney Co., *181 Connor Engineering Corp-, .Insert 800- AIR TRAPS (Sm TVups, Aw) Buenaod-SUCCT, Inc-, *73 Buffalo Forge Co., *2o2 Carris Corporaturn, *74-75, 130 Oarage Fan Co., *74,205 finetlnewtai Air niters, Inc., *154 DoQmger Corp., *165 Joy M&. Co., *210-211 Mario CoQ Co., *68 D. J. Murray Mfg. Co., *125 Niagara Blower Co., *87 Feerfaes Eleetrie Co, Tbe, *218 Trane Co.. Tbe, .U6-139 Western Blower Co., *224 Weatingbouse Eleetrie Corp., Btmlevant Dir., .175. 225 ALUMINUM DUCTS (Sm Dud*. ALUMINUM FOIL. Insolation Philip Cany Mfg. Co., The, *444-447 Infra Insulation, Iao, *455 Johns-ManriUe, *450-451 Reftectal Corp., 8ub- of Borg-Wamer, 453,455 AMMONIA COILS (Sm CeOs, Asa inriUa, *450451 H. W. Porter A Co., Inc. 430 Re&eetal Corp, Sob- of Borg-Waraer. 453, 455 Reid Hayden Inc, *430 ASSOCIATIONS AmerWn GaS Assn, *100-101 Copper and Braes Research Assn., *154 ATMOSPHERIC COOLING TOWERS (5m Cooling Town, Ateaoepierie) AVVUWB4* 1 vow OHniei, AW awtic; Cot Burner*; OH Bunn; Sicken) A*. IU|. UV.,"nTW Air Control Produete, Inc, *138 Air-Factors, Inc, *243 American-Standard. Plumbing A Heat ing Div., *318-319 Auer Register Co., *245 .Burnham Corp., *324 Campbell Seating Co., *114-115 CarnesCorn., *248-049 P-nlnmHi. Bcuer Co. of Pottetown, *343- 343 Crane Co., *323-323 Donbem-Busb, Inc, *405-409 Ri^inwnwU Djy. of fiftiwi*u**T Con trols Corp., *144 Feddm Corporation. *131 General Automatic Prodnet* Corp., *310 General Eleetrie Co., *33-63 Hart A Cooley Mfg. Co., *260-251 Independent Register Co., The, *255 Kritser Radiant OoQs, Ine., *311 Kruegv Air Conditioning Corp., *256 National Clay Pipe Mfrc, The, 414 317 National-U. 8. Radietor Corp., Heating A Air Conditioning Dir.^ *328-327 Herman Nelson Div., Anew Air Fil ter Co-Ine^ *128-129 ' John J. Nesbitt, Inc, *142 Raypak Co.. *352 RittW Cerp., The, *193 Ehaw^Perkin* Mfg. Co, *312 Trane Co.. The, *138-139 Tuttle A Bailey, *255-259 United States Register Co., *250-261 Vulcan Radiator Co., The, Insert Beo- tion Warren Webster A Co., 416417 WeB-MeLain Co.. *338 Wests Eleetrie Heater Co., *148 Edwin I*. Wiegand Co., *148-147 Young Radiator Co., *143 BELLOWS ' Flexonice Corp., *297 Robertahaw-Fultnn Controls Co., Ful ton Sylphon Div., *284485 U- 8. Flexible MeteDie Tubing Co., ' Keflex Mfg. Dir., *298-303 BENDS, Pipe. Ferrous and NonFerrous Indtsh Co, The, *305 BLOCKS. Asbestos Philip Carey Mfg. Co., The, 445H47 Johne-Maavilb, *458-451 New York Blower Co., Tbe, *215 Peerless Electrio Co., *216 Sheldons Engineering Ltd., *220 Terriogton Mfg. Co., The, *221 Westinghouse Eleetrie Corp., Sturtevani Div., *178. 225 Whitty Cos ine., *361 L. J. Wing Mfg. Co., *148-141 BLInOgWERS, ^eating and VentflatAerovent Fan Co.. Ine., *197 Airfan Engineering Co., *198 American Air Filter Co., Inc, *158-160 American Blower, Div. of American- Standard, *6649 American Foundry A Furnace Co., 104-106 Bayiey Blower Co., *200 Brookside Corporation, *201 Buffalo Forge Co.. *203 . E. K. Campbell Co., *116 Century Fan A VentilatorCo., Ine., *203 Champwn Blower A Forge Co., *304 Chicago Blower Corp., *306 Clarage Fan Co., *76. 206 Ptynmatio Carp., *79 Garden City Fan Co., *208 General Blower Co.. *209 Bg Elective Ventilating Co., *134, 214 Joy Mix. Co., *210-211 Iarm Ine., *108 Lau Blower Cov Tbe, *213-218 Leman Industries, Ido., >109, 123 MeQuay, loo., *133-133 Herman Nelson Div., American Air Fil ter Co., Ino-, *128-129' John J. Nesbitt, Ine.. *143 New York Blower Co., The. *215 Niagara Blower Co., *97 Pcerkae Electrio Co.. Urn. *216 Reveor.lne., *219 Tarrington Mfg. Co Trade-Wind Motor------ . _ Trane Co., The. *136-139 Utility Fan Corp., *113 Viking Air Products, Div. of Natioaat- U. S. Radiator Corp., *223 Western Blower Co., *224 Wettingbouse Electric Oorp., Sturtevant Div., *176, 225 Edwin L. Wiegand Co., *14^147 L. J. Wing Mfg. Co., *148-141 BLOCKS. Clans Owens-miaou. *441 Pittsburgh Coning Carp., *442 BLOWER HOUSINGS Airfan Engineering Co., *118 American Blower, Div. '* ` Standard, 46-erf Champion Blower A Forge Co., *204 Clarage Fan Co., *78,206 Garden City Fao Co., *208 Lao Blower Co.. Tbe, *213-313 Peerless Electric Co.. Tbe. *216 Revcor, Ine, *219 Utility Fan Qxp, *113 BLOWERS. Centrifugal (Sm Fobs) BLOWERS, Pressure Aerovanl Fan Co., Ine., *197 American Blower, Div. of American- Standard. *66-69 Bayiey Blower Co, *289 Brookside Corporation. *201 ' Buffalo Forge Co., *202 Century Fan A Ventilator Oo, *203 Champion Blower A Forge Co., *281 Chicago Blower Carp., *205 Clarage Fan Co, *76,206 . Deeomatio Products, Inc, *77 General Blower Co, *209 Ilg Ebetrio Ventilating Co., *134,214 Joy Manufacturing Co., *210411 U Blower Co.. The. *213-213 . Peerless Electric Co., The, *216 - Tarrington Mix. Co., Tbe, *221 Westicgbouse Electric Carp., Sturtevant Div., *176, 225 L. J. Wing Mfg. Co., *140-141 i (Sm Fens, Supply asctcbi ran i^o, ino, *iv> Aladdin H**tig Corp., *199 American Blower, Div. of American- Standard, *68-69 Baytey Blower Co., *200 Broo&de Carp., *201 Buffalo Forge Co., *203 Century Fan A Ventilator Co., Inc., 203 Champion Blewer A Forge Co., *204 Chicago Blower Corp., *205 Clarage Fan Co.. *78, 206 General Blower Co., *209 Ilg Electrio Ventilating Co., *134, 214 Joy Mfg. Co., *218411 Lao Blower Co.. The, *213413 Herman Nebon Div.. American Air Fit ter Co., Ine., *1*8-139 BLOWERS, Turbine General Blower Co., *209 Western Blower Co., *224 L. J. Wing Mfg. Co.. *140-141 BLOWERS. Warm Air Furnace Aladdin noting Corp.; *199 American Blower, Div. of . Standard, *66-0 Clarage Fan Co., *76, 206 Ess Blower Co., The, *213-213 Tarrington Mfg. Co., The, *221 Utility Fan Con., *113 Viking Air Products, Div. of Nationai- U. S. Radiator Corp., *223 L. J. Wing Mfg. Co., *148-141 BOILER-BURNER Air Devices, Inc., *155. 248-241 Aldrich Co., *337 Numerals following Ma&nfnctutesa' Names refer to pages bs tbe Catalog Data Section Index to Modem Equipment 9 American-Standard, Plumbing A Heat ing Div., *318419 __ _ Babcock A Wiloax Co., Tbe, *359 p~~w Engineering A Supply Co., Inc., 331 Bryan Steam Carp.. *344 Burnham Corp., *324 Cleaver-Brooks Co-. *340441 Columbia Boiler Co. of PotUtown, 442- 343 Cyriotherm Div., Natioaai-U. 8. Radi ator Corp., *345 Fitxribbone Boiler Co., Ibc., *347 Orr A Sembower, Ine., 451 Titusville Iron Works Co., Tbe (Div. of Frtsgibbons Boiler Co., Ioe., *347 General Automatic Products Corp., 410 Gardoo-Piatt, Ins., *359 Hydrothmn, Ioe., 448 International Boiler Works Co., The, 449 8. T. Johnson Co., 474-375 Johnston Bros., Ine., 450 Mettler Co-, Ine., Tbe, Div. of Eclipse Fuel Enin. Co., 476 Natioaal-U. O. Radiator Corp, Heating A Air Conditioning Div., *325427 Orr A Sembower, Ino., 451 Parifie Steel Balm Div., National-U. 8. Badiatar Corp., 428429 Peeriess Heater Co.. 430431 ^ __ Pennsylvania Furnace A Iron Co., *111, Fetro, 478479 , Ray Burner Co., 477 Raypak Co., Ine., *352 H. B. Smith Co., Ine., Tbe, 433 Spencer Heater, Lyeomiog Div., Aveo Mfg. Corp., 438435 Titusville Iroo Works Co., The, (Div. f StrutbeiB-WeQs Corp.), 453 Weil-HcLajn Co., 436 Western BoQer Co., *356 Btrothers-Wells Corp.), *353 Western Boiler Co., *255 York-Shipley, Ine., 430 BOILERS. Gas Fired Aldrich Co., *337 ' AmwiftuiAunAiwi Kewaoas Boiler Div., 438 American-Standard, Plumbing A Heat ing Div., 418419 Babcock Wilcox Co., The, *339 Bailer Engineering A Supply Co., Ine., 321 Bryan Steam Corp., 444 Burnham Corp., 424 Cleaver-Brooks Co., 448441 Columbia Boiler Co. of Pottetown. 443 343 Crane Co., 433423 ' Cydotherm Dir., Natioeal-U. 8. Ra diator Corp., 445 Federal Boiler Co.. *346 Fitsgibbons Boiler Co., Ine., *347 General Automatic Produete Co., 410 ' Hydrotberm, Ine., 448 International tti"'*** Works Co., The, 349 Johnston Bros., Ino., 450 National-U. S. Radiator Carp., Heating A Air Conditioning Div., *325427 Orr A 8embower, Ine., 451 Pacific Steel Boiler Div^National-U. S. Radiator Corp.. 428-329 Peerless Heater Co.. 430431 Pennsylvania Furnace A Iron Co., *111, 333 - Raypak Co., Ine., 452 H. B. Smith Co., Iwt, The, 433 Spencer Heater,- Lyeoming Div., Aveo Mfg. Corp., *334435 Titusville Iron Works Co., The, (Div. of BOILERS, Cost-Iron American-Standard, numbing A Heat ing Div., 418419 Burnham Corp., *324 - Crane Co., 425433 Federal Bcuer Co., 446 Struthera-Wells Corp.), *353 Vapor Heating Corp., *354 Weil-MeUin Co.. 436 Weston Boiler Co., *355 . Worthington Corp., Air Conditioning A Refrigeration Div., *95 ' York-Shipley, Ino., 480 ' Hydrotherm. Ine.. 448 National-U. S. Radiator Corp, Heating A Air Cnnditinninif Div., *325437 Peerless Heater Co., 438431 Pennsylvania Furnace A Iron Co., *111, 332 Speneer Hem Mfg. Corp., .......... WeB-MeLain Co., *330 BOILERS. Heating Aldrich Co^ *337 American-Standard, Kswanee Boiler Div., 436 Babcock A Wiloax Co^, The, *339 Boiler Engineering A Supply Co., Ino., 431 . Bryan Steam Corp., *363 Burnham Corp., 424 Cleaver-Brooks Co., *340441 Colombia Boiler Co. of Pottetown, 443 BOILERS. Coal-Fired - ' 344 American-Standard, Plumbing A Heat Crane Co., 423423 ing Div., 418419 Cydotherm Div., Natioaal-U. S. Ra Babcock A Wilcox Co., 439 diator Corp., 4(5 Burnham Carp., 474 Federal Boiler Co.. *346 Crane Co^ 422423 Fitsgibbons Boiler Co., Ine., *347 FUsgjbhons BoQer Co., Inc^ 447 . General Autocnatin Product* Co., 410 International Rl" Works Co., The Hydrotherm. Ine., *348 449 Johnston Bros., Ine., 450 International Boiler Works Co., The, 349 National-U. 8. Corp., *328427 Peeriees Heater Co., 430431 H. B. Smith Co.. Ine., The. 433 8. T. Johnson Co., *374475 Johnston Bros., Ino., *350 Natioaal-U. S. Radiator Corp., Spencer Heate^l^cuaiag Div., Aveo A Air Conditioning Div., 425427 Titusville Iron Works Co., The (Div. of Strothers WeBs Corp.), 453 WeD-Melain Co-, *336 Otr A Sembower, Ine., 451 Pacific Steel Boiler Div., National-U. S. Radiator Corp,. 438429 Peeriea Heater Co., *330431 Pennsylvania Furnace A Iron Co., *111, BOILERS. Down Draft American Standard. Kswanee Boiler Div., *338 Chaver-Brooke Co., 440441 Johnston Brae., Inn., 450 Titusville Iren Works Co., The (Div. of Strutbsa-Wdb Corp.), 453 BOILERS, Fire Tube i American^tandard, Kewasee Boiler Div., 433 , 333 Fetro, 478479 Raypak Co.. Ine., 452 H. B. Smith Co., Ino., The, *333 Spencer Heater, Lyeoming Div., Aveo Mfg. Oora., 434433 Titusville bon Works Co., The, Div. of Strutben-WeUs Corp., 1453 Vapor Heating Corp., **54 Wefl-MeLain Go., *T)9 Western Boiler Co., 455 York-Shipley, Inc., 480 BOILERS. High Temperature, Water Cydotherm Div., National-U. 8. Radi ation Corp^ 445 International Boiler Works Co., Tbe. 449 H. B. Smith Co-.Ioc-, The, *333 Vapor Heating Corp., 454 Aldrich Co., 437 Div., 438 AuuuimnJlUnitonl, Phimhing A Heat ing Div., 418419 Babcock A Wiloax Coa Tbe, 439 Boiler Engineering A Supply Co., Ine., 421 Bryan Steam Corp., 444 Burnham Corp., *324 Cleaver-Brooks Co., 440441 Columbia Boiler Co. of Pottetown, 442 343 Crane Co., 423423 Cydotherm Div., Nationsl-U. 8. n-- diatcr Corp., 445 Federal Boiler Co., 446 Fitsgibbons Botier Co., Inc., 447 General Automatic ProductsOorp., 410 International Boiler Works Co.. The. 449 8. T. Johnson Co., *374475 Johnston Bros, Inc., 458 Nstkmal-U. S. Rrimtnr Carp., Heating A Air Conditioning Div., 425427 Or A 8embower, Inc,. 461 Pacific Steel Boiler Div., National-U. S. Radiator Corp., *328429 Peerless Hester Co., 438431 Petro, 478479 H. B. Smith Co., Ine^ The, 433 8peneer Heater, Lyeoming Div- Aveo Mfg. Corp., 434436 . Titusville Iron Works Co^ The, Div. of Struthers-WeUs Corp., *363 Vapor Hestiw Carp., 454 Wdl-MoLein Co., 436 Western Boiler Co.. 455 . . York-Shipley, In&, 480 BOILERS. Steel Aldrich Co., *337 . American-Standard, KewaiMe Boiler Div., 438 Bryan Steam Carp-, *344 Burnham Corp., 424 Cbaver-Brooke Co., 448441 Columbia Boiler Co. of Pottetown, 442 343 Crane Co., 422-323 Cydotherm Div., Natiooal-U. 8. Ra diator Corp., 445 Federal Bailer Co., 44$ Fitigibbons Botier Co., Ine., 447 General Automatic Products Co., 410 International Botier Works Co- The. 449 S. T. Johnson Co., 474475 Johnston Brae..Inc., *350 Natiooal-U. S. Radiator Corp., H--tiwy A Air Conditioning Div., 425427 Orr A Sembower, Ino., 451 Pacific Steel Boiler Div., National-U. S. RadiatorCorp., 428429 Petro, *378479 Sponger Heater, Lyooming Div., Aveo MfgTCorp., *334435 Titusville lion Works Co., The, Div. of Struthere-WeDs Corp., 453 Western Boiler Co., 455 York-Shipley, Inc., 480 BOILERS, Unit Steam Generator American-Standard, Kswanee BoQer Div., 438 , Boiler Engineering A Supply Co., Ino., 421 Cleaver-Brooks 440441 Colombia Botier Co. of Pottetown, 442 843 Cydotherm Div., National-U. S. Ra diator Corp., 445 Fitxgibbons Botier Co., 447 International BoQer Work* Cx, The. 449 Johnston Bros., Ioe., 450 Ott A Sembower. Inc., 451 Titusville Iron work* Co-The, Div. of Sttuthere-WeOs Corp., 453 Please ntioa THE GUIDE 1959 when writing to Advertisers BOILERS. Water Tube American-Standard, Plumbing A Heat. ing Div., 418419 Babcock A Wilcox Co.,The. 439 Bryan Steam Corp., 444 Columbia BoQer Co. of Pottetown, 449- Isternatiosal Boiler Wort* Co. The. 449 Raypak Co-. Ino., 452 H. B. Smith Co., Ino., The. 423 Trtnevffle Iron Work* Co, Tim, Div. of Strutbere-Well* Corp., 453 Vapor Heating Carp, 454 BRACKETS, Radiator Nahonal-U. S. Radiator Carp, ff-- A Air Conditioning Div, 425427 BREECHINGS Pennsylvania Furnace A Iron Co, *111, BURNER PROTECTION. Gaa nd Combustion Control Div, Electroaim Corp. of America, *294 Mereotd Corp, The, *289 Minnea|oHs-HoacyaeD R*gnM^, ' Penn bontrols, Ine, *281 BURNERS. Automatic Aldrich Co, 427 Arkla Air ConditiomngCorp, *102 Onhmihte Botier Co. of"Pottetown, 442- Enterprue Engine A M^Mr_y Berner Div, Sub. of General Corp, *272 Gordon-PSatt, Ine, 469 Industrial Combustion, Ioe, 473 6. T. Johnson Co, 47*475 Msttier Co, Ine., The, Div. of Fuel Engtg. Co, 476 Petro, 478479 Ray Burner Co, 477 Wm-Burt Co., The, 463463 ' York-Shipley, Ino., 480 BURNERS, ComMnation foe Nat ural and LP Gaaes Arkla Air Conditioning Corp., *102 Gardon-KstL Inc, *369 Mettler Co., Ine., The, Div. of Fuel Engm. Co, 476 Pennsylvania Furnace A Iron Co, *111^ BURNERS. ComUnatloo Gas g Oil Babcock A Wilcox Co, Tim, *339 Enterprise Engine A Machinery Co, 8ub. at General Metals Corp, *37J Oordon-Pistt, Ine., 469 Industrial'Combustion, Inc, 473 6. T. Johnson Co, 474-375 Mettler Co, Ine, Tbe, Div. of Edicee Fuel Ecgrf. Co, 476 w Orr A Bciiibowei, Ine., 451 Petro, *375479 Ray Burner Co., 477 Bow"** Burner Co, *370 York-Shipley, Inc., 480 . BURNERS. Gas GS Gat Burners) BURNERS, Gas Conversion (See Oat BURNERS, OU (Sm Oil Sunwre) CALKING, Building CAPS, Vent Flue Amerivent, A Div. of American Metals Products Co, Ino., 465 G. C. Breidert Co, The, *233 >10 1959 Guide CASTINGS. Bronze end Nkxkri Metal Arthur Bun A Co., *308 Air Centred Product*. Inc, *338 Air-Factara, Inc., *W _ . , American Warming A Ventilating Co., The, *226 AuerRachtcr Co.. The, *246a Barber-Ocrfman Co-, *217, 27* Cam Corp., *246-249 Coonor Engineering Corp., *Inert Sec tion Charles Demath A Boos, Inc., *294 Thcrmotank, Ine, *243 Titus Ml*. Carp., *lBsert Section. United States Register Co., *260-261 CEILING PANELS Burgos-Manning Co., Architectural . Products Dir., *309 CEMENT. Asbestos Philip Carey Mfg. Co., The. *446-447 Johna-ManviHe, *450-461 . CTMENT, losolatlag Armstrong Cork Co., *444 Philip Carey Mfg. Co., The, *448-447 Johcx-ManvOto, *450-451 Krmm unr Wfg. VAh, a * Johna-ManriBe, *456-451 CHILLERS. liquid or Water Acme Industrie*. Inc., *64-66 Arkia Air Conditioning Dorp-. *102 Bd) A Gossett Co., *M2-38S Kennard Dir., American Air Filter Co., Ian., *85 Acme Industries, Inc., Addison Products Co., *97 a Aurcricaa-Stapdard. Ptomfaing A Heat ing Dir., *318-319 Arkia Air Conditiooi Bril A Outset* Co., -** Curtis Mfg. Co-, Refrigeration Dir., *193 Dunham-Bush, Inc-, >406 409 Kritser Products, A Dir. of P America, Inc., *103 ' McQuay, Ine,>122-123 ` Metalbestoa Dir., ffn. WallaM Co-> 360-387 CIRCULATORS. Ho(Water Heating Bell A GoairttCOy *382-383 Chicago Pump Co., Sab. Food Ma chinery A Cnemieal Corp., *396-397 Domestic Pomp A Mfg. Corn., *335 Dunham-Bush, Inc.. *406-4(9 Jam. P. Marsh Corp., *433 H. A- Thntab A Co.. *380-391 Trane Co., The, *136-139 Edwin L. Wiegand Co., *1<6-U7 _ CLAMPS AND SLEEVES. Pipe Regtojiu Pipe Opsin, CZeaps and COILS. Aluminum American Blower, Dir. of American- Standard. *66-69 Diayer-Hanaon, Inc., Dir. d Nationsl- U. 8. Radiator Corp., *78 45 Air Conditioning Cent, *80 G AOMaaulactumigCo,The,*190 Patterson-Kelley Co., Inc.', The, *191 Trane Co., The. *138-139 Westinghouse lap.U it Corp., Sturterant Dir., *176,225 Worthington Corp., Air Cond'g A Re frigeration Dir., *95 actoud vvp., >ioe*i M. Blaser A bon., *43 Drayer-Hanaou, Dir. of Natiooal-U. S. t>.<4u>. Corp.. *78 Dunham-Bush, Ine. *406-409 Mario Ceil Co., *68 McQuay, Inc., *132-133 Niagara Blower Co., *87 Pattrivon-KeHey Co., Ine., The, *191 Rririgtrstion Appliances. Inc, *112 Trane Co., The. *136-139 Worthington Cap.. Air Cond'g A Re frigeration Dir., *95 York Corp., Sub.Berg-WanxrCorp^ *96 COILS. Blast Aerofin Corp., *188-187 . American Blower, Dir. of American- Standard. *66-69 M. Blaser A Son. *93 Prayer-Hanson, Dir. of National U. 8.- Radiator Corp., *78 Dunham-Bush, Inc., *406-409 Gorernair Corp., *84 Industrial Engizaering A Equipment Co-, *146 Kennard Dir., American Air Filter Co., Inc.. *85 Mario Coil Co.. *86 McQuay, Inc., *132-133 D. 7. Murray Mfg. Co.. *135 New York Blower Cn, The, *2U Niagara Blower Co., *87 Recold Corporation, *90-91 Rdrigeration Appliances, Inc., *112 Trane Co..The. 136-129 Vulcan Radiator Co., The, Insert Seo- Aerofin Carp., *186-187 Airteap Drv, Chrysler Carp.. *88-99 American Blower, Dir. of American- Standard, *66-69 M. Blaser A Son, *S Dole Rdrigerating Co., *194 Drayer-Hartson, Dir. of National-U. S. Radiator Cana, *78 Tit*. _ *406-409 45 Air Conditioning Carp., *80 Fluor ProdueteCo., A Di. cd The Floor Corp., Ltd., *179 Frick Co., *195 G A O Mfg. Co., The, *190 General Electric Co., *82-83 Gorernair Corp., *84 Arthur Harris A Co., *308 Kennard Dir., American Air Filter Co., Ine, *85 Kritxer Products, A Dir. of Peeriesa of America, Ine., *103 Larco, Inc., *108 Mario Coil Co., *88 McQuay, Ine., *132-133 D. 7. Murray Mfx. Co., *135 Herman Nelson Dir., American Air Fil ter Co., Ine., *128-129 John J. Nesbitt, Ine., *142 New York Blower Co., The, *215 Niagara Blower Co., *87 Patterson-Kelley Co., Ine., The, *191 Retold Corporation, *90-41 Rdrigeration Appliances, Inc., *112 Trane Co., The, *136-139 Westinghouse ElectricCorp., Sturterant Dir., *176, 225 Worthington Corp., Air Cond'g A Re frigeration Dir., *95 Young Radiator Co-,'*143 COILS. Pipe. Copper Arthur Hama A Co., *30B Niagara Blower Co-, *87 Reeold Corporation, *90-41 York Corp., Sub. Borg-Warner Carp-, *96 COILS. Pipe. Iron Niagara Blower Co., *87 Resold Corporation, *90-41 COILS. Pipe Tube, Noofm- Arthur Harris A Co., *308 - giiMwx Engineering Corp., *387 McQuay, Inc., *182-123 Niagara Blower Co., *87 Patterson-Kdky Co.. Ine., The, *191 Recold Ccnxnstioe, *90-41 * rod Engineering Co.. Inc.. *383 COILS. Stainless Steel Arthur Harris A Co., *308 Diaycr-Hansoo, Dir. of National-U. 8. Radiator Corp., *78 McQuay, foe., *132-133 Niagara Blown Co., *87 Patterson-Kelley Co., Inc, The, *191 Richmond Engineering Co., Inc., *388 Trane Co., The, *136-139 Tula Corp., formerly Tula Water Beat- COILS. Tank Genera] Fittings Co., *386 Pattenon-Kelley Co., Ine., The, *191 Richmond FVfin**' inf Go., *388 Western Blower Co., *224 COLLECTORS, Fijr Aah American Blower, Dir. of Standard, *66*69 V. D. Andersoo Co., The, Dir. of Iliter- rmtiooal Basic Economy Corp., *40446S COMPRESSORS. Air American Blower, Dir. erf American. Standard, *66-69 Bril A Gossett Co., *282-383 Binks Mfg. Co., .178 Brunner Dir., Dunham-Bush, Ine., Curtis Mfg. Co., Rsfrigexatioo Dir., *193 Dunham-Bush, Ine., *406-409 Johnson Service Co., *276-277 Joy Mfg. Co.. *210-211 Nash Engineering Co., *398-399 Worthington Corp., Air Cond'g A Re frigeration Dir., *95 COMPRESSORS. Rdrigeration American Blower, Dir. of American- Standard. *66-69 Brunner Dir., Dunham-Bush, Inc., *406-409 Carrier Corporation. *74-75, 130 Curtis Mfg. Co., Refrigeration Dir., *193 Dunham-Bush, Inc., *406--409 Frick Co., *195 Trane Co., Tim. *136-139 Worthington Corp., Air Cond'g A Re- frigtntion Dir., *95 York Corp., Sub- Borg-WarnexCant* *96 CONDENSERS. Air-Cooled and Wa rm-cooled (Set alto Air-eooUd and Water-Coded Condeneert) Acme Industries. Inn, *64-65 Adseo Div, Yuba Consolidated Indus tries, Inc.. *296 Amerimn Blower, Dir. of American- Standard. *66-69 Baltimore AircoJ Co* Ine.. *177 BeU A Cornett Co.. *382-383 Carrier Corporation. *74-75, 130 Crane Co., *332-323 Curtis Mfg. Co.. Refrigeration Dir., *193 Drmyex-Hansm, Dir. of Natiooal-U. 8. Radiator Corp., *78 ' Dunham-Bush, Inc, *406-409 . f5 Air Conditioning Corp., *60 Feddos Corporation, *131 Frick Co, *195 . GAO Mfg. Co, The, *190 . Gorernair Carp, *64 Kennard Dir, American Air Filler Co, Inc, *85 Killcbrew Engineering Corp, *387 {Critic Products. A Dir. of Peerless of America, Inc, *103 larco, Inc., *108 Mario Coil Co., *86 McQuay, Ine., *132-133 Niagara Blower Co, *87 Pattexson-Keliey Co., Inc., The, *191 Reeold Corporation, *90-41 Refrigeration Appliances Ine., *113 Kittling Corp, The, *192 TrsasCo, The. *130-1 Worthington Corp., Air Cond g A Ra- frigeratioa Dir, *95 York Corp, Sab.Borg-WareerCorp.. *96 d Liquid Gat, Vapor) Products Co.-, Inc., *365 Dura-Vent Corp., Affiliate of 1 Mix. Dtv.orf Dover Corp, *388 Bart A Cooley Mix. Co.. *256-251 Metalbeatos Div^WaKam Wallace Co., 266-367 .- Westinghouss Electric Corp., Sturterant Dir., *176, 225 Young Rmr1--Co., *143 COILS, Brass Arthur Harris A Co., *308 McQuay, Inc., *132-133 1 Trane Co., The. *136-139 COILS. Cooling Acme Industries, Inc., *64-65 Addisoo Products Co., *97 ' - T rnBi-- iatu., *n U. 8. Flexible Metallic Tubing Co, Ko- flex Mfg. Dir., *296-303 COMPRESSOR REFRIGERANTS GSm [UfrigcranU, Flaaermotsrf Hy&ro- Gencral Chemical Dir., Allied Chemi cal Carp., *81 - H. W. Porter A Co, loo., *430 Reid Hayden, Inc, *430 Rio-wiL Ine., *431 Durant Insulated Pipe Co, Ido., *429 H. W. Porter A Co, Ine, *430 Retd Hayden, Ins, *430 Rio-wiL, Inc, *431 United Sheet Metal Co, *288 Numerals following Manufacturos' Names refer to pages in the Catalog Data Section Index to Modem Equipment >11 CONNECTORS. Flexible Ammkan Brass Co, The, American MybJ Hose Dir, *149 . Duro-Dyne Corp, *266-267 jtxonica Corp., Expansion Joints Dir, RAbLtebaw-Fuhon Controls Oo, Ful ton Sylphon Dir, *286-287 TT S Fsxtible MetiRie Tubing Co, Ke flex Mfg. Dir, *298-303 Wiremold Co., The, *289 CONTROL. Acoustical (Sss Aeonstical Control) McDonnell A Miller. Inc. *856-359 Mercoid Corn., Tbe, *280 , - . Robertshaw-Fulton Controla Co., Ful ton Sylphon Dir, *286-287 - Whilo-Rodgeia Co., *290 . CONTROLS. Combustion, Auto matic Air for Stokers WDl-Burt Co, Tbe, *362-363 ' CONTROLS. Draft (5m Draft Control, Barometric) .. Field Control Dir. of H. D. Conker A Co, *293-293 ' .' CONTROL, Air Volume Damper AL Mfg. Co, *344-245 Air A Refrigeration Corp, *W Air Control Products, Inc., *238 Air Dorises, Inc, *155,246-241 Air Distribution Product*, *219 Air-Faetcrs, Inc., *343 - A>r>*wwwn Foundry A FurnaceCo, *104- 105 .' . American Warming A VentOatihg Co.', The, *228 . Anemmtat Corporaturnof America, In sert Section Barber-Cohnan Co, *247, 271 (twiiww Engineering Carp, Insert See- Duro-Dyne Carp., *286-267 General Controls, *272-273 Hart A Cooley Mfg. Co, -256-251 Independent Register Co., The. *255 Johnson Serrioe Co., *nW71 Krueger Air Conditioning Corp, *256 Mumeepolie-Hoaeywell Regular-- Cr'o, 170, 281 Powers Regulator Co, Tbs, *284-285 Titus Mfg. Co, *Inseri Section United States Reciter Co, *266-361 Waterloo Register Co, *265 Young Regulator Co., *262-263 CONTROL. Boiler Water Lord Leslie Co, *378 Maid-O'-Mist, lac, *413-413 McDonnell A Miller, Inc., *358-359 Merecxd Carp., The, *280 Watts Regulator Co, *426-427 Warren Webster A Co, *416-417 CONTROLS. Water Level Robertsbaw-Folton Controls Co., Pul- ton-Srlpbon Dir, *286-287 IesiieOo, *278 Maid-O'-Mtst, Inc., M19-4U McDonnell A Miller, Ina, *358-381 Mercoid Corn, The, *280 - Penn Controls, lac, *283 Viking Air Products, Dir. of National-- U. S. Radiator Corp, *223. . Watts Regulator Co, *436-427 L/UBWD'DWl, UK.. 1W W Eleetromode Dir. d Commercial Con trols Corp, *144 -' Industrial Engineering A Equipment Co, *145 . National-U. S. Radiator Carp., Heating A Air Conditioning Dir, *325-327 Herman Nelson Dir, American Air Fil ter Co, Ine, *126-129 Rittling Corp., The, 192 Bhaw-Ferkiaa Mfg. Co, *312 Trane Co, Tbe, *136-139 Warren Webster A Co, *416-417 Wesx Electric Heater Co, *148 . Edwin L. Wiegand Co, *146-147 Young Radiator Co, *143 CONTROL EQUIPMENT. Air Con ditioning, Electric, Combustion Barber-Cohnau Co, *247,271 ' Combostioa Control Dir, Eleetioaim . Corp. of America, *294 General Controls, *272-773 Mercoid Carp, The, *280 Minneapolis-Honeywell Regulator Co, 170,281 - Rimpter Mfg. Co, Tbs, *295 White-Rodxtsa Co, *296 WUoolator Co, The, *291 - April Showers, I__ ,__ Barber-CoJinan Co, *247,271 Fsnjet Div, MueUcrmist Irrigation Co, 459 Hinecajicps-Honeywell Regulator Co., CONVECTORS AND CONVECTOR ENCLOSURES - A-J Mfg. Co., *244-245 Airtberm Mfg. Co, *326 Auwriean-Standard, Plumbing A Heat ing Div, *318-319 Dunham-Bush, Ine., *406-409 Fedders Corporation, *131 GAO Mfg. Co, The, *190 Kritser Radiant Coils, Inc., *311 National-U. S. Radiator Corp, Heating A Air Conditioning Dir, *326-377 Herman Nelson Dir, Amerimn Air Fil ter Co, Ine.. *123-129 - Pacific Steel Bailer Dir., Nstinnsl-U. 8. p.-lut-- Corp, *326-329 Rittling Carp, Tbe, *19) Trane Co, The, *136-139 Tuttle A Bailey, *268-259 Vulcan Radiator Co, The, *Inaert 8eo- CONTROLLERS AND CONTROL EQUIPMENT. Electric. (Set Humid ity and Temperahtn Control) Baite-Colman Co, *247, 271 General Controls, *272-273 Uhnciit Enoneering Co, Dir. of Ameri can Air Filter Co, Ine., *418 Mcreoid Corp, The, *280 Penn Controls, Inc, *283 Powers Regulator Co, Tbe, *284-285 Ranco Inc.. *288 Wesx Eiectrie Hester Co, *148 . CONTROLLERS. PNEUMATIC {Sot CaabeOers onrf Ceatrei Kaefnsiinif, Uc<nic) . CONTROLLERS, Pump Illinois Engineering Co., Dir. of Ameri, can Air Filter Co., Inc., *418 Leslie Co, *278 Jas. P. Marsh Corp., *423 ' Warren Webster A Co, *416-417 Edwin L. Wiegand Co, *146-147 Young o*^i*<w Co, *143 COOLING EQUIPMENT. Air Acme Industries, Ine., 64 68 Addison Products Co, *97 Aerofin Cp, *188-187 Aerorent Fan Co., Ioc, *197 Airfaa Engineering Co, *198 Airlemp Dir, Chrysler Corp, *96-99 Airtberm Mfg. Co, *320 American Btower. Dir. of Amerimn- Standard, *66-61 April Showers Co, Ine., *458 Arkia Air Conditioning Corp., *102 Bril A Cornett Co, *382-383 . Buensod-Stacey, Inc, *73 Carrier Corporatiou, *74-75, 130 Chicago Steel Furnam Co, *117 Clange Fan Co, *76,206 .. Crane Co, *322-823 Curtis Mfg. Co, Bririgeiatfdn Dir, *193 Darn Engineering Corp, *385 ' . , DeBothexat Fans Dir, American Ma chine A Metals, Ine., *287 Dole Refrigerating Co, *194 /. Prayer-Hanaon, Dir. of National-U. 8. Radiator Corp, *78 ' . . . f5 Air Coaditkming-Corp, *80 ' Fanjet Dir, MatlVmnat irrigation Co, 459 . Farr Co, *16B-169 - ' - - General Automatic Products Co., *810 General Electric Co, *82-63 Joy Mfg. Co, 210-211 Kennard Dir, American Air Filter Co, Inc., *85 Kritser Products, A Div. o! Peerlees of America, Inc, *105 lem, Inc., *108 Lennot Industries, Ino, *109, 122 Msjestie Co, Ino, The, *110 Marin Coil Co, *86 McQuay, Inc., *132-133 D. J. Murray "Mfg. Co, *135 Herman Nelsoo Dir, AmericanAir Fil ter Co., Ine., *126-129 Niagara Blower Co, *87 Pennsylvania Furnam A Iron Co, *111, 332 Reeold Corporation, *96-91 _ ' Refrigeration Apptmaoea, Inc.,' *112 Rittling Corp, *192 ' TmneCo, The. *U6-139 Wed-McLain Co., *336 . Westinghouae ElectricCorp, Sturterant Dir, m, 225 Wilson Engineering Carp, *360 Worthington Carp, Air Cond'g A Re frigeration Dir, *95 Young Co, *96 COOLING EQUIPMENT, OO . Acme Industries, Ino., *66-65 Adeco Dir, Yuba Consolidated Indus tries, Inc, *296 Amerimn Blower, Div. f American* Standard. *66-69 ' Baltimore AircoQ Co, Ino.. *177 Bril A Gomett Co, *383-383 Binks Mfg. Co.^ *178 ' Dark Engineering Corp.. *365 Drayw-Hsnwm, Dir. erf National-U. 8. Radiator Corp, *78 Majestic Co, Inc, The, *110 NationsJ-U. 8. Radiator Corp, Heating A Air Conditioning Dir, *325-327 Patterson-Krilay Co., Ino., The, *191 Reeold Corporation, *90-91 ' ' Trane Co, Tbe. *136-139 Worthington Corp., Air Cond'g A Re- frigoatioa Dir, *95 . Yula Carp, farmaiy Tula Water Heat- COOL1NC EQUIPMENT, Water (Sss Water Cooling) Acme Industries, Ino, *64-65 Addison Produets Co, *97 Adaoo Dir, Yuba Consolidated Indus- trim, Ine., *290 Aerofin Carp, *t86-187 Airfsn Engineering Co, *198 American Blower, Div. of American- Standard. *66-69 Plumbing A Heat ing Dir, *318-819 Baltimore Aireotl Co., Ino., *177 , Bril A Gossett Co, *381-383 Binks Mfg. Co, *178 , Brunner Div, Dunham-Bush. Inc., *406-409 Carrier Corporation, *74-75, 130 Curtis Mfg. Co, Refrigeration Div, 193 Davis Engineering Corp, *385 Dole Rringerstins Co, *194 Drayer-Hansoa, Div. <rf Natiooal-U. 8. Radiator Corp., *78 .. Dunham-Bush, Inc, *406-409 Fanjet Div, MurilermMt Irrigation Co, Fluor Products Co, A Dir. of TbeFluor Corp, Ltd., *179 - Frick Co, *193 E. D. GoodfeQow Co, Ino, *180 - Gorernair Corp, *84 *. Kennard Div, American Air Filter Co, Inn.. *85 gm**>Tw Pininwiln| ftorp, *887 Inroo, Ine, *108 - Majestic Co, Inc., The, *110 Mariey Co, The, *183 McQuay, Ino., 132-133' . Natiocal-U. S. Corp., A Air Condittoning Div, *325-377 NiagM* Blower Co, *87 Pattesoo-KeOey Co, Inn., Tbe, *191 . Pennsylvania Furnam A Iron Co, *111, Phillips Cooling Tower Co, Inc., *184 Reeold Corporation, *96-91 Refrigeration Appliances, Ine., *112 Trane Co, The, *136-139 . Worthington Corp, Air Cond'g' A Re frigeration Div, *95 . York Corp., Sub. Borg-Warner Corp., *96 Yula Corp., formerly Yala Water Hmt- ers, Ino., *393 COOLING TOWER FANS Aerovent Fan Co, 1m., *197 American Blower, Div. of Asrnimi- Standard, *66-69 Binks Mfg. Co, *178 ' Havens Cooling Towers, Div. of Havens Shuctural Steel Co, *180 ' Brcokside Corp, *201 Clarage Fan Co, *7L 206 Floor Producta Co.. A Div. of Tbe Fluor Coip, Ltd, *179 liiie-Hoffmann Coding Ttowera. Ine.. 183 - Mariey Co, The. *183 Tomngton Mfg. Co, Tha. *231 Utility Fan Corp., *113 Viking Air Products. Div. of Nstkmal- U. S. Radiator Corp, *223 . COOLING TOWER SILENCERS General Sound CooLrol, Im, *433 Ekrf Hsnason, Inc., *435 Industrial Acoustics Co, Ine., *436 COOLING TOWERS. Atmospheric. Mechanical Draft, Forced Draft, Induced Draft (5sx Cooltag Equip ment, Water) Acme Industries, Ine, *64-65 Air A Refrigeration Corp, *63 Airtemp Div, Chrysler Carp, *98-99 Amerimn Btower, Div. of American- Standard. >1541 * Baltimore AircoQ Co, Ine, *177 Binks Mfg. Co, *178 Bueaeod-atamy, Ine., *73 - Carrier Corporation, *74-75, 130 Curtis Mfx. Co, Refrigeration Div, *193 Prayer-Hanaon, Div. of Natkmal-U. 8. Rsdrmtqr Corp, *78 - Dunham-Bush, Ine.. *406-409 ' Fluor Products Co, A Div. of The Fluor Corp, Ltd, *179 E. D. CoodfsBow Co, Inc, *180 Governair Carp, *64 Havens Cooling Towers, Div. of Havem Structural Steel Co, *180 Kennard Div, American Air Filter Co, Ine, *85 Lennox Industries, Ino., *109 liiie-Hnffmsnn Cooling Towera, Inc, *183 Mariey Co, The, *183 Mario Coil Co, *86 D. J. Murray Mix. Co, >U$ PhiUipe Coaling Tawtz Co, Inc., *154 Reeold Corporation, *96-91 Refrigeration Appliances, Ine , hj CORROSION. Treatment of . y American GQtooite Co, *423 Dtuant Insulated Pipe Co, *429 Durant Insulated Pipe Co, Ine, *429 OwenaGorning Fibrigla* Carp., *171, 440 . Rio-wiL Inc., *431 COUPLINGS . Gastin-Baoon Mfg. Co., *434 Koppsa Co, Ine. Metal Products Div, *437 . Young Regulator Co, *262-283 ' COVERING. Pipe and Surface ' American Gilscnita Co, *428 , . ' Please mention THE GUIDE 1999 when wrlttnft to Advertisers tsr sr 12 1959 Guide d Pipe Co., The, *429 d Pipe C" T - *" Johns-MaavQk. 450-431 LOJ Glue Fibers Co.. *435-439 Owens Cominf Fiberglas Coro, *171, 440 Owens-IHinoia, *441 Pittsburgh Corning Corp, *442 H. W. Porter A Co., Iso., *430 Rtflsotal Corp, Son. of Barz-Wamer *45>,4S6 Reid Hayden, Ido., *430 Rio-wiL Ine, *431 Wood Coaveraioo Co.. *457 CUT-OFFS. Low Water Barber-Cotman Co., *347. >71 Geacrml Controls, *373-272 Maid-CMist, Ine., *419-112 Mwooicl Carp, The. *380 Watte Rrouktar Co, *420-427 Warren Webster A Co, *410-417 DAMPER REGULATOR SETS Barber-Caiman Co.. *247, *71 Dura-Dyne Corp., *280407 Field Central Div. ofB.D. Conkey A Co., *299-003 General Controls, *279-072 Hart A CooleyMii- Co, *230-231 Hereoid Corp.. The, *280 Simplex Mlg. 60.7*203 Tuttle A BaQey. *268-239 United Statu Berate? Co.. *280-231 Young Regulator Co, *289-283 DAMPER REGULATORS, Boiler (Se&nlrlm) Simplex Mfe. Co.. *293 DAMPER REGULATORS, Fumaco Dura-Dyne Corn, *289-287 Field Control Div. cif H. D. Conkey A Hart'A Cooky Mlg. Co, *230-231 Merooid Carp, The, *280 Simplex Mlg. Co, *293 - United Statu Hsgbtar Co.. *280-261 Yoon* Regulator Co, *289-283 DAMPERS. Air Volume Control A-J Manufacturing Co, *944-945 Air Contra! Products, Lnc., *238 Air Device*, Ino, *133,240-241 Air Distribution Prodtie' American Foundry * 104-103 American Warming A Ventilating Co., The, *228 Amineman Co, Ino, *231 Anemoatat Corporation ci America, *In- ert Seetioa Auer Register Co, Tbe, *248 Barber-Colman Co, *147, 271 Carau Corp., *243-249 Connor Engineering Carp., `Insert Seo- American Warming A Ventilating Co., Tbe. *228 imwiiwiwn Co, Ine,, *231 Bahnsmi Co, The. *72 Barbo-Colman Co, *247, 271 Bueneod-Staeey, Ino, *73 Canter Corporation, *74-73, 130 Dora-Dyne Carp, *288-287 Minnesgtis-Hooeywell Begolatar Co, Yoong Regulator Co, *289-283 DEFLECTION GRILLE (Su Urines, ffrftrfm and Omemtntat Metal Wart, alto Looter*. Bcpisten) A-J Mlg. Co, <244445 Air Central Products, Ine, *238 Air Deriou. Inc, *135, 940441 ' Ameriun Warming A Ventilating Co, The, *293 Auer Register Co, Tha, *243 Bahnsrm Co, The, *72 Barber-Ccdman Co., *247, 271 Cornu Corp., *248-249 Bart A Cooky Mlg. Co, *230431 Hendrick Mlg. Co, *239433 Independent Register Co, The, *233 Krueger Air Conditioning Corn, *238 Titus Mlg. Corp, *Ineert Section Tuttle A Bailer, *238-239 United Statu Co., *280461 Univernal Diffuser Corp, *284 Waterloo Register Co, *283 Young Regulator Co, *289483 DEHUMIDIFIERS AHriiym Products Go, *97 Air A Refrigeration Corp, *83 American Blower, Dir. of American- Standard, *8849 Bayley Blower Co, *290 M. Blaser A Son, 43 Buensod-Stacey, Ine., *73 Buffalo Forge Co, *203 Carrier Corporation, *74-73, 130 COarage Fan Co, *78, 208 Dcsomatic Products, Ino, *77 Dryomatio Corp., *79 Kntser Products, A Div. of Peerieu <rf Awrip* lac., *103 Mario Cou Co, *88 New York Blower Co, The, *213 Niagara Blower Co., *87 Pittsburgh Lecirodryer Diy, MoGraw- Edison Co., *89 Westingbouae Eleetrie Corp, Startsrant Div, *176, 223 York Carp, Sub- Boeg-WnroerCarp, 46 DETECTORS, Smoke (5 Smoke De tectors and Indicators, for Fine* and Ducts) DRAFT CONTROL. Barometric Field Control Div. of H. D. Conkey A Co, *299493 General Controls, *279473 Natiooai-U. 8. Radiator Corp, tr-- A Air Conditiodng Div, *329-827 Simplex Mfg. Co, *2#5 Whitty Co, Ino., *381 Buffalo Forge Co, *202 Century Fan A Ventilator Co. Oarage Fan Co, *76,208 Joy Mlg. Co, *210411 Westingbouse Electric Corp, Div, *178, 223 Whitty Co, Inc, *281 L. J. Wing Mfg. Co, *140-141 DRIERS, Refrigerant Dryomatio Corp, *79 Henry Valve Co, *274 Mueller Brace Co, *434 DRYING EQUIPMENT Aerorent Fan Co, Ino., *197 Air Device*. Ino., *155,240441 American Blower, Div. of American- Standard, *8849 Campbell Heating Co, *114-118 Chicago Steel Furnace Co, *117 nwnra osnrar Tbermobloa Div, Prat-Daniel Corp, Trane Co, Tbe. *139-139 cur Lnrvico. me., nw. **v Buensod-Stacey, Ine, *73 Connor Engineering Carp., Insert Sec tion H. H. Robertson Co, 43 Thermotank, Ino., *242 DUCT CONNECTORS. Prefabri cated American Brass Co, The, American Metal Han Div, *149 Dura-Dyne Corp., *288-287 DUCT FURNACES (See Beaten. Duct) DUCT SILENCERS Armstrong Cork Co, *444 Oeneral Sound Control, Ine., *433 Gustin-Bacoa Mlg. Co., *434 TM f Hansson, Ino, *433 Owena-Corniag Fiberglas Carp., *17L 440 Soooao Products Co, *384 United Sheet Metal Co, Ine., *288 United State* Register Co, *269-251 DUCTS, Ventilating Airfloor Co. at Calif, 413 American Brass Co, The, American Metal Horn Div, *149 Sonoeo Products Co, *394 Wircxaoid Co, Ttw, *289 av r liter vatp.i *iau Amerian Air Filter Co, Ine, *136-118} American Blower, Div. of American- 403 Buffalo Forge Co, *202 Ekctro-Air Cleaner Co, Ine, *168 Farr Ca, *1M-1W General Eleetrio Co, *88-83 Joy Mlg. Co, *210-211 Koppera Co., Ine., Metal Products Div. United Sheet Metal Co, *288 ELECTROSTATIC AIR CLEANERS Air-Maxe Corp, *137 Airtemp Div.. Chrysler Carp., 48-99 American Air-Filter Co, Ine., *139-160 Dellinger Coop, *183 Electro-Air Cleaner Co, Ino., *166 General Electric Co, *89-83 Mh>iw*i*ik.HoMyll Regulator Co, 1707281 Westuigboase Electric Corp, Sturtevant Diy, *173,223 ELECTROSTATIC PRECIPITA TORS (See Filter*) Koppera Co, Ine., Mstel Products Div., EVAPORATIVE CONDENSERS (See EVAPORATIVE COOLERS Acme Industries, Ine, 4445 Airfan Engineering Co.. *198 Arkla Air Conditioning Carp, *102 Baltimore Aireoil Co, Lie, *177 litiling Corn, The, *192 (lbs Mfg. Carp., *LBsert Tuttle A Baiinr, *238459 United Sheet Metal Co, United Statu Register Co, *260481 DAMPERS. Mechanical American Foundry A Furnace Co., 104-103 DISTRICT HEATING {See Common, Treatment of--Expansion Joint*--Ineolation, Undttyrivnd--Meter*, Pipe) DISTRICT HEATING. lUgh-tanpernture Fluid Systems Ameriun Gilsanite Co., *428 Durant Tw**t***4 Kpe Co, *429 Durant Insulated Pipe Co., Ine, *429 DOORS, ACCESS, for Paco, Cu ing Baboon Co, The, *72 DUCTS. AIR CONDITIONING. HEATING AND VENTILATING. Under Concrete Floor Slabs Airflow Co. of Calif, *313 Johns-ManvQle, *450-451 Sonoeo Products Co, *334 DUCTS. Flexible American Brass Co, Tbe, American Metal Hose Div, *149 U. 8. Flexible Metallic Tubing Co, Ke flex Mlg. Div, *298-303 Wiremola Co, The, *289 DUCTS, Prefabricated Airfloor Co. of Cab/, *313 American Beam Co, Tbe, American Metal Hoee Div, *149 Dura-Dyne Co, *286-287 Gustin-Baenn Mlg. Co, *434 Jobaa-ManviHe. *430-451 EVAPORATIVE ROOF COOLING SYSTEMS April Showers Co, Ine., *458 Fanjet Div, Huelkrmkt Irrigation Co, EVAPORATORS Adieu Div, Yuba Consolidated Indus tries, Ine.. *296 American Air Fitter Co, Ine, *168-160 American Blower, Dir. ol Amerimn- Bell A Cornett Co, *389-383 Davis Engineering Corp, *383 Dale Refrigerating Co, *194 Drayer-Hanson. Div. of National-U 1 Radiator Corp, *78 Kritzer Products, A Div. of Peerless e -- inn, *un Mario Coil Co, *88 MeQuay, Ine, *139-133 Recold Corporation, 49-91 RMrigsmtioo Appliances, Ine, *119 Trane Co..The, *136-139 Young Radister Co, *143 Numerals flowing Manufacturers' Namee refer to pages In tbe Data Section Index to Modem Equipment 13 EXHAUST HEADS (See Bead*, Eskoott) EXHAUST SYSTEMS. Undtrtoor and Overhead Ammomao Co, Ino., *931 EXHAUST TUBING. Flexible (See Tubing. Flexible, Metallic) exhausters Aeroveat Fan Co, Ine, *197 Air Devices. Inc, !. 8EwS&.-t( Sundard, *66-69 Ammerman Co^Ine^jrfSl Bayley Blower Co, *200 "ClBieidertCo, *232 Braokside Carp.. *201 Buffalo Forge Co, *M2 gS^TIi^rA9Fa.Co,.*04 .,, SSSwt Fans Div, American Ma chine A Metals. InoGarden CSty Fan Co, 408 General Blower Co, *209 gSST&S-SS. o... p;.:% .h Air Products Co, Ine, *234 Joy Mfg. Co, *219411 Leu Bknw Co, Tbe, *219-213 Muekk Mfg. Co, *233 New York Blower Peertesa Electric Co, The, *218 Penn Ventilator Cc^,,*236 ___ Propdkir Div, Robbins * Myers, inc. Reed Unit-Fans, Ino. *218 ... Trade Wind Motorfasa.Ine, *222 Trane Co, Tbe, *138-139 _ , Westingbouae Electric Corp, Sturtevant Div, *178, 223 L. J. tfing Mfg. Co, *140-141 EXHAUSTERS. Laboratory Fume American Blower, Div. of Aasroan; Standard, 46-69 Ammerman Co., Ino., *231 Carnes Corp, *249-249 General Blower Co, 409 jenn aI* Producta Co, Inc, *234 Muekk Mfg. Co, *233 tries, Ine., *296 American Tut* Philip Carey ui- -- .-- ,, DeBotbesat Fans Div, American Ma chine A Metals. Ice., 407 Durant Insulated Pipe Co, *429 Durant Insulated Pipe Co, Ine, *429 Flecomes Corp, Expansion Jcsnt Lnv, mi2n9d7s Engineering Div, American .A.ir Filter Co, loo.. *158-1* Pipe line development Co, The, 406 Robertsbaw-Fulton Cra^rok Co, Ful- too-Syipbon Div, 4934S7 U S. Fkxibfc MeWlic Tubtng Co, Ke flex Mfg. Div, *299-303 Warren Webster A Co, *416-417 EXPANSION LOOPS . Durant Instituted Pipe Co, *429 Durant Trnnt****1 Pipe Co, Inn, *429 Rio-wiL, Ine., *431 EXPOSITIONS _ . FABRIC. Duct (Se* Duet Fabrie) FAN BLADES Aeroveat Fan Co, Ine, *197 Braokside Corporation, *201 Revcar, Inn, 419 Tacrington Mfg. Co, Tbe, *221 FAN MOTORS (See Meter*. Electric) FAN SILENCERS __ General Sound ContraL Ine., *433 Ekf Haaasoo, Ino., *<35 Industrial Acoustics Co, *436 FANS, Attic __ aiw Cooler A Ventilator, Ino., *130 American Btower, Div. of Amerian- Philip Carey Mfg. Co, The. *448-447 Champion Blower A Forge Co, *294 Leu Blower Co, Tbe. 419-313 Muekk Mfg. Co, *233 Peerless Electric Co, The, 416 Reed Unit-Fans, Ine., *218 Revcar, Ine., 419 Trade-Wind Motorfans. Ine, *223 Viking Air Products, Div. of Nateonal- U. S. n*i*<* Carp, 423 FANS, Axial Flew Aeroveat Fan Co, Inc, *197 Allen Coder A Ventilator, Ine., *230 Amerian Blower. Div. cf American- Standard, *68-89 Ammerman Co, Inc, *231 Bahnsoa Co.. The. *73 Brookside Corp., *201 -------- Forge Co, *202 * Blower Cap, !'" Fans Div,------ rhino & Metals, Ino., *207 Tig Electric Ventilating Co., *134, 214 Jenn Air Producta Co, Ine, *234 Joy Mfg. Co, 419-211 . . New York Blower Co,'The, *213 Peerless Electric Co, The, *216 Penn Ventilator Co, *238 Propellair Div, Robbins A Myers, Inc. 417 Reed Unit-Fans, Ino., *218 Revccr, Ine, *219 Toningtoa Mfg. Co, *221 Trade-wind Motorfans, Ine, *223 Trane Co, The, *136-189 Western Enpnwu-mg A Mlg. Co, *237 Westingbouae Electric Corp, Sturtevant Div, *223 L. J- Wing Mfg. Co, *140-141 FANS. Centrifugal Aerorent Fan Co-, Ino., *197 Airfan Engineering Co, *198 Aladdin Hating Corp., *199 _ Amerian Blower, Div. of Amerian- Standard, 68-69 _ Ammerman Co, Inc., *231 Bayky Blower Co, *209 Broowde Corporation. *201 Buffalo Forge Co, *202 EL K. Campbell Co, *116 Carrier Corporation. *74-78, 139 Champion Blower A Forge Co, *204 Chicago Blower Corp., 405 Oarage Fan Co, *76, 206 DeBotbesat Fans Div, Amerian Ma chine A Metals, Inc , *207 . Garden City Fan Co, *208 _ General Blower Co, 409 Hireehcean-Pohle Go, Ino., *233 Hg Ekctric Ventilating Co, *U4. 214 Jenn Air Products Co., Ino, *234 Joy Manufacturing Co, 419-211 Muekle Mfg. Co.. *233 . .. _ Nelson Div, American Air Fu - ter Co, Inc., *128-129 New York Blower Co, Tbe, 413 Niagara Blower Co, *87 Peeneea Ekctrio Co, The, *216 Penn Ventilator Co, *226 Revcar, Ino.. *219 __ __ Torringtao Mfg. Op, The, 4X1 Trade-Wind Moterfana, Ine., *222 Trane Co, The, *139-139 Utility Fan Coni-, *113 Viking Air Producta, Div. d Natwnal- U. 6. Radiator Corp.. *223 Western Blower Co., 444 Wratinghouse EkctneCorp, Sturtevant Div, *223 Whitty Co, Ine, 461 - FANS, Electric ,, Aerorent Fan Co-, Ine, *197 Air Controls, Ine.. *188 ABa Cooler A Ventilator, Ine, *230 Amerian Blower, Div. of Amerian- Standard, *89-69 G. C- Brodert A Co., Tbe, *232 Cbunmon Blower A Forge Co, *204 Dole Refrigerating Co, *194 Hagan Mfg. Co, *449 __ Hiraehman-Pohk Co, Ino., *233 Tig Ekctric Ventilating Co, *134, 214 Lou Blower Co, The, 419413 Propellair Div, Robbins A Myers, Inc., 417 __ Trade-Wind Motorfans, Ine, *222 Utility Fan Corp, *113 _ Viking Air Producta. Div. of National- U. S. P|-'*1*- Corp, *223 Western Engineering A Mlg. Cti, *237 Westingbouse Electro Carp, Sturtevant Div, *223 L. J. Wing Mfg. Co, *149-141 FANS. Furnace Aladdin ri--tlwy Carp-, *199 American Blower, Div. of Amerian- Standard. *66-W Champion Blower A Forge Co, *294 Clange Fan Co, *78,206 Joy Mfg. Go, 410411 Tarringtoo Mfg. Co, The, *221 Utility Fan Corp, *113 Viking Air Producta, Div. of Nsttonal- U. B. Radiator Corp, *222 Whitty Co, Ine., 481 L. J. Wuxg Mfg. C , *140-141 imi*i pq*w Co, Ine., *231 Bayky Blower Co, *200 Bunak Fence Co, *203 Champion Blovw A Forge Co, *204 Chicago Blower Corp, **5 Clarage Fan Co, *76,206 DeBottwzat Fans Div, Amerian Ma chine A Metals, Ine., *207 Garden City Fan Co, *208 General Blower Co, 409 Joy Manufacturing Co, *310-211 Muekk Mtt Co, *233 ,,, ,, Pacific Steel Bailer Dir, National-U. 8. Radiator Corp, *323-329 Propefiair Dfv, Robbia A Myers, Ine., Sheldons Tiigiiiaeilni Ltd., *220 Westingbouae Electric Corp., Sturtevant Div, *233 Whitty Co, Ine., 481 L. J. Wing big. Co, *140-141 FANS. Portable Aerovent Fan Co, Ina, *197 iiiirim Blower, Div. of Amerian- Champion Blower A Forge Co, *204 General Blower Co, *209 tig Electric Ventilating Co., *134, 214 Joy Mfg. Co, 419411 Lau Blower Co, The, *219413 Propctiair Div., Robbins A Myers, lue, *217 . Reed Umt-Fans, Ino., *218 Tjernlund Mfg. Co, *127 Tcsrington Mfg. Co, Tbe, *221 L. J. Wing Mlg. Co., *1)-H1 FANS. Propeller Aerovent Fan Co, Ine, *197 Alien Cooler A Ventilator, Ine, *230 American Blower, Div. of American- Standard, *66-69 Ammerman Co, In&, *231 Buffalo Forge Co, *202 Century Fan A Ventilator Co, *203 Chicago Bknrer Cotp.^405 Ctuage Fan Co, *76.206 DeBotbesat Fans Div, Amenan Ma chine A Metals, Inc, *207 Co, Inc., *233 Itg Electric Ventilating Co, *134, 214 Jenn Air Products Co, Inc., *234 ~ s Co, Inc., Metal Products Div. Lau Blower Co, The. *219-313 Muekk Mfg. Co, *233 FUrr-mw Nslson Div, American Air Fil ter Co, Inc, *128-129__ _ _ New York Blower Co, Tbe. *214 Peerkss Electric Co, The, 416 Penn Ventilator Co., *230 PropeOair Div, Robnins A Myers, Ine., E1457 when writing to Advertisers Torrinrton Mfg. Co, Tbe, *221 Trade-Wind Motorfans, Inc., *223 Trane Co, The. *138-139 Viking Air Products, Div. of National- U. 3. Radiator Corp., *223 Western Blower Co, *224 Weston Engineering A Mfg. Co, *337 L. J. Wing Mfg. Co, *149-141 FANS. Supply and Exhnust Aerovent Fan Co, Ino., *197 Airfan Engineering Co, *193 Aladdin Heating Corp, *199 Alien Cooler AVentuator, Inc, *230 American Bkwer, Div. of American- Standard, *83-69 Ammerman Co, Inc, *231 Bayley Blower Co, *200 Binks Mfg. Co, *178 Buffalo Forge Co.. *202 Philip Carey Mfg. Co, The, *446-447 Century Fan A Ventilator Co, Inc., *203 Champion Blower A Forge Co-, *294 DeBothoat Fans Div, American Ma chine A Metals, Inc., *297 Garden City Fan Co, *208 General Blower Co, *209 Hirschman-Pohk Co, Inc., *233 Ilg Ekotrie Ventilating Co, *134, 214 Jean Air Producta Co., Ino., *234 Joy Mfg. Co, 410411 Iau Blower Co, 419-313 Muekk Mfg. Co.. *233 Herman Nelson Div, American Air Fil ter Co, Ine., *128-129 New York Blower Co, The, *215 Peerless Ekctrio Co-, The, *216 Penn Ventilator Co, *238 PropelIsit Div, Robbins A Myen, Inc, 417 Reed Unit-Fans, Inc., 418 Trade-Wind Motorfans, Inc., *222 Trane Co, Tbe, *136-139 Utility Fan Coip, *113 Viking Air Products, Div. of National- U. 3. Radiator Cop-, *223 Western Engineering A Mfg. Co., *237 Wratinghouaa Electric Corp, Sturtevant Div, *225 L. J. Wing Mfg. Co, *140-141 FEEDERS. Boils Water A. W. f---* Valve Mfg. Carp, *419 Cydotherm Div. of NatsansJ-U. S. Ra diator Corp, *343 Maid-O'-Mkt, Ine, *419-113 McDonnell A Miller, Inc, *358459 Watte Regulator Co, *429-427 Warren Webster A Co, *416-417 FELT. Insulating (Set Insolation Fell) FELT. Sound Deadening Armstrong Cork Co, *444 - Philip Carey Mfg. Co, The, *448-447 L.O-F Glass Fibers Co, *439-439 Owens-Caruing Fiberglas Carp, *440 Wood Conversion Co, *437 ~ FIBER INSULATION (Sss /nstdarim) FILTERS, Air (See Air Cleonin* Egwipmtni) Air A Refrigeration Carp, *83 Air Devices. Inc, *165, 240441 S Air-Filter Corp, *158 x Air-Maze Corp, *157 V. D. Anderson Co, Tbe. Div. ol Inter national Basic Economy Corp., *404- 403 Burke A Co, *182 Cambridge Filter Corp., *183 Continental Air FQten, Iso., *184 DoOinger Coro., *185 * Ekctro-Air Cleaner Co., Ins., *188 George Evans Corp., The, *187 Farr Co.,*168-169 General Ekctrio Co, *83-83 Joy Mfg. Co, *3Uk211 Muekk Mfg. Co, *235 t >14 1959 Guide Owens-Coroing Fiberglea Carp., *171 Pittsburgh Rate Glass CO-, Fiber Glass Dir., *171, 443 Raoncb Product* Carp-, *173 FILTERS. Air Throwoiy American Air Filter Co., Inc., <153-166 CoetiDental Air FQtsa, toe., *154 FILTERS. Air, Copthmoos. Aato mstic Air-Man Corp...157 Ameriean Air Filter Co., Int, <156-180 V. D. Aadenoa Co., The, Dir. of Inter national Baaic Economy Corn., 404 40$ ' ' Continental Air Filter*, Inc., *104 DoDinger Corp., <165 Electro-Air Cbattf Co., Inc., <166 Farr Co., *168-180 Trioa. Inc., *174 FITTINGS. Hot Water n**<in Systems American Tube Prodoi Ine., *384 Bell A Qoasott Co., *3L. . Flezoniea Corp., Expansion Joints Dir. 297 - Hammond Braes Work*, *Insert fl****TM Maid-O'-Mist, Ine., *411-413 Jas. P. Marsh Corn., *433 National-U. S. Radiator Corp., A Air Conditioning Dir., .*338437 Pipe line Development Co., The, *306 Saroo-Sarootherm, *414-416 Taco Heatsa, Ine., *363 H. A. Thrush A Co., *300-891 Trane Co., The, *136-139 Warren Webster A Co., *416-417 FITTINGS, Jacketed, Steam mad i-^rraopjpcai no, *ewe Tube Turns, A Dir. orf Cbentettoa Carp.. *307 FITTINCS. Wrot Solder Type Anerites Braes Co.. The. *160-151 Mueller Bran Co., *434 - FLANGES. Cehenlied or Noo-Pcrroos ladish Co., *306 Babcock A Wilcox Co.. Th Tubular Produeta Dir., *304 ladteh Co., *306 .. Tube Turin. A Dir. g( Chemetron Corp., *307 Mariey Co., The, *183 Mario Cm) Co., *86 MeQuay, Ine., *133-133 Phillip* CoolingTower Co., Ine., *184 Recold Corporation, *00-91 FUEL BURNING EQUIPMENT. Automatic (5*s fanrn, Automatic; Gas Burner*; OO Burners; Statin) FUEL OIL. Heating, Pumping and Straining Unit* S. T. Johnson Co., *374-378 Petto. *378-379 FUME DISPOSAL DUCTS. Vitri fied Clay - National Clay. Pipe Mfgrs., The, 314- FILTERS. Electroatatic Predplta- Air-Man Corp., *157 American Air Flits Co-, Inc., *168-160 Barnebey-Cheney Co., *161 DoDings Corp-, *165 Qactro-Air '"Iranm Co., Inc., *166 Gensal Eieetric Co., *86-63 Minncagtia-Hopeywell R*gnl<fa*> Qg^ Trie, Ine., *174 Westinghoon Eieetric Corp., Starterant Dir., *176 FILTERS. Gas . Air-Man Corp., *157 American Air Fflts Co.. Ine., *168-160 V. D. Aadenoa Co., The, Dir. o( Inter national Basie Eooaomy Ccrp_ <404 406 Baniebey-Cbeaey Co-, *161 Bollinger Corp-, *185 Electro-Air Ckaw Co., Inc.. *186 Trioa, Ine., *174 FILTERS. Grease Air Derioee, loe^ *165, 340-341 . Air Filter Corp., *166 Air-Mero Corp.. *167 Amerimn Air Flits Co., be, <153-180 Burke A Co.. *163 Continental Air Flltera, Inc., *164 Pollings Osp^ *165 Geos* Erase Corp., The, *167 F__m_t..C.*o1,6<81-61*6--9 Research Products Corp., *173 Trioa. Ino., *174 Voctox Co., *178 Babcock A Wilcox Co., Products Dir., *297 ladah Co., *306 National Clay Pipe Kfra., The, *314- FTTTINGS, Pipe, Alloy ad Stain* lees, Noolsrous Babeoek A Wilcox Co., The, Tubular Prodncsts Dir., *397 Ladish Co., *305 Tube Turns, A Dir. erf Clmmebun Corp., *307 FITTINGS. Pipe, Flanged FITTINGS, Pipe for Oadaflmuad Conduit Durant Insulated Pipe Co., *429 Durant Insulated Pipe Co., Ine., *439 National Clay Pipe Mbs., The. *314H. W. Ports A Co., Ino., *430 Reid Hayden, Ino., *430 Rie-wiL Ine., <431 FITTINGS, Pipe. Gnlmlxed I^i.h Co., *306 United Sheet Metal Co., *388 FILTERS, Liquid Air-Maxe Carp., The, *167 Pollings Corp., *166 Henry Velre Co., *374 Krainl Co.-Ine., The, *400 Richmond Engineering Co-, Ion., *388 ____________i, Inc., <43$ Industrial Anouxtira Co., Inc., *436 FILTERS, Odors . American Air Filter Co., lac-, *168-160 Barnebey-Cheney Co^ *161 Burke A Co.. *163 - Connor Enginesing Carp^ 'Insert Sec tion Minnrxjxdia-Hooey well Regulator Co., Research Produeta Corp., *173 ladish Co., <3&S FITTINGS. Pipe. Sramlraa Welding Babcock A WBeux Co., The, Tubular Products Dir., <301 Ladish Co.,1*305 Pipe Line Derdopmeat Co.. The. *308 Tube Turns, A Dir. of Chemetron Corp.. <307 FITTINCS. Pipe. Socket-Welding Co., *305 Pipe line Development Co., The, *308 FITTINGS. Pipe. Solds American Braes Co., The, *160-151 Moeller Brass Co., *434 FITTINGS. Pipe, Steel Babeoek A Wiloox Co., The, Tubular Produeta Dir,, *304 . Henry Valre Co.. *374 ladam Co., *305 Pipe line Development Co.. Tie, *808 Tube Turoa, A Dir. orf Cbemetitm Corp., *307 FITTINGS. Air Coodltfoniog and Warm Air Furnace CS*e Fvraoet Ftps end Ftctutgs) FITTINGS. Welding Babeot A Wiloox Oo., The, Tubular Product# Dir., *304 ----------- ------------t Co., The, Tubular Products Dir., *304 ' Tadi*h Co., *305 Tube Turin, A Dir. orf Clnmetroa Corp., *307 FLANGES. Pipe, Reducing Babeoek A Wucox Co., The, Tubular Products Dir., *394 ' ladish Co., *306 Tube Turns, A Dir. of Chemetron Carp., *307 FLANGES. Pipe. Steel Babeoek A Wiloox Ch The, Tubular, Products Dir., *304 Henry Valre Col, *274 ladish Co., *305 Pipe line Uerelopmen* Co-.The. *308 Tube Turns, A Dir. of Chemetron Corp., *307 Produeta Dir., *304 Henry Yalre Co., *374 ladish Co., *305 . Pipe line Dwebpaat Co., Th*, *398 Tuhe Turns, A Dir. of Chemetron Corp., *307 FLOATS, Ferrous end Nosfcrroaa (5erica) Arthur Harris A Co-, *308 FLOATS. Welded-Stainless. Mood. Plated Steel Arthur Harris A Co., *308 FORCED DRAFT COOLING TOW* BRS (Sas Cooling Tbwers, Induced Draft, Felwwl Draft) Anns Industries, Ine., *44-65 Air A RMrigemtioo Corp., *63 Airtemp Dir., Chryris Carp., *98-99 Ameriean Blows, Dir. rf American- Baltimore AirooB Co., Inc., *177 Onier Corporation, *74-75, 180 Diaycr-Hanson, Dir. eg National-UB. Radiator Corp., *78 Dunbem-Bush, Ino.. *406-409 Fluor Products Co., A Dir. of The Fluor Corp., Ltd.. *179 . B. D. Goodldlow Co^ Ino.. *180 Harem Pooling Tower*. Dir. of Hareus Structural Steel Co., *181 Keaaard Dir., Ameriean Air Elite Co.. Ino., *85 Iilkv-Hoffgmin Cooling Tower*. Ine., 183 FURNACES. Duct (Sss Heelers, Dwet) FURNACES. Electric Eleetromoda Dir., Commeraal Controls Corp., *144 Temnnt Industrie*, Ine., *t09,133 Weriz Electric Heater CoM *148 Edwin L. Wiegand Co., *116-147 FURNACES. Gas-Fired. Floor Airtberm MIg. Go., *330 American Foondiy A Furnace Co., 104-t05 Chicago Steel Furnace Co., *117 Draro Corpj, *118 Jackson A Church Dir., York-Shipley. Ine., *119 Johnson Heater Corp-, *130-131 Industrie*, Ine., <109, 13> Mammoth Foresee Co., The, *123 National Heater Co., *124-126 National-U. S. Radiator Corp., Heat ing A Air Conditioning Dir., *326-327 Tbemobloe Dir., PmV-Daniel Corp., FURNACES, OQ Burning, Floor American Foundry A Furnace Co., 104-106 -. Chicago Steel Furnace Co., *117 Draro Corp., *118 General Automatic Product#Corn., *310 Jackson A Church Dir., York-Shipley. Inc., *119 Johnson Heater Carp., *120-121 Mammoth Furnace Co., The, *123 National Heater Co., *134-126 FURNACES. Suspended Airtemp Dir., ChryalerCorp., *96-99 Airtberm Ml*. Co.. *320 Chicago Steel Furnace Co., *117 ' Crane Co., *323-323 Draro Corp., *116 General AutomaticProdueta Corp., *310 General Electric Co.. <83-63 Ha^es^FUrnaee Mfg. A Supply Oo., Jwhai A Church Dir., York-Shipley, Ine., *119 Johnson Heater Corp., *126-131 Lennor Industries, Two *109,122 Majestic Co., Ino., The. *110 Mammoth Furnace,. Toe. *123 National Heater CeM *134-126 Natiooal-U. 8. Radi*tar Corp^ Heating A Air Conditioning Dir., *325-327 ' Twites Heats Co., *33(1-331 Tbsmobloo Dir., Prat-Daniel Corp., Numerals following Manufacturer** Names refer to pages In the Catalog Data Section Index to Modem Equipment 15 FURNACES. Wall D^VeoiCorp., Affiliate of Peeriees Mix. Dir. of Do*u Corp., <368 Waix Etietric Heater Co.. *148 FURNACES. Warm Ab.Hteary Duty Ah Derice*. Ino., .ISM*-241 Airtberm Mfg.- Co., *329 Aladdin Heatmg Carp.. *M9 _ American Foundry A Furnace Co., E.*K*C^.b*Il.CoA*Ufl,,,_,ii Campbell Heating Co-. *n4-US Cam^Corporatioo. <7WS, tJ CUeago Steel Furnace Co., *117 ^Furnace Mfg. A Supply Co., Church Dir.. York-Shipkry. e inte.J.o*1b1o9son Co., *374-3_75 HSttr (%.. *WH l*n Industnea, me., M9, *** Rajeztic Co-, lac.. The, *110 jir^mnth Furoaee Co., The *123 Nstteal Heater Co^ *124-125 N^tarol'U. 8. Radiator Corp., Hrotrng A Air Cioditioning Dir., *325-827 Herman Nataoo Kr, Amenean Air Filter Co., Ine-, *123-129 . Petto, <378-W9 Rar Bums Co., *377 ,. TShwrmohtoc Dir., prat-Daaid Corp., Tjernlond Mfg. Co., *127 FURNACES. Warm Ab. RmWence Airtemp Dir., Chrysler Carp-. *88^9 Aladdin Heating Ckrp., *199 Crane Co.. *323-323 . , ,, Dura-Vent Corn.. Affiliate orf Pee Mix- Dir. of Dover Corp.. *268 __ Geeoal Automatic Produeta Omp^ <310 General Electric Co., *83-83 Hayee Furnace Mfg. A Supply Co.. j,*WwlA Church Dir., York-Shipiey S. T. Jdhueoo Co.. 374-33T__ Johnson Heater Corp., 13(til21 Industries, Ine., *109, 122 Majestic Co., Iml. The, *110 Nstional-U. 8. Radiator Corp-, Heating A Air Conditioning Dir., *326-327 Peeriees Heater Co., *3Sh331 Feanaylranta Furnace A Iron Co., *111, 132 Ray Burner Co., *377 Trane Co-, The, *136-189 ,, _ York Corp.. Sub. Borg-WarnerCorp., *96 York-Shiptey, Ine., *380 Petto, *373-379 Ray Burner Co., *377 Sooner Burner Co., *370 GAS FILTERS (See FtUcrr, Oat) GAS SAFETY PILOTS (Be* Pdett) GAS VENTS ., Amerirent, A Dir. orf American Metal Produeta Co., Ine.. *365 . Dura-Vent Corp., Affiliate orf Peerie* Mfg. Dir. of Dorm Corp . <K8 Hart A Cooley Mfg. Co., *356-251 Metalbesto* Dir., William Wallace Co., 366-367 _ . .. National Clay Pipe Mlgra., Ine., *314- 317 . GLASS BLOCKS Owcas-Hlinoa, *441 Pittaburgh Corning Carp., Foamgjae Dir., *40 GOVERNORS. Pump Leslie Co., *378 _. Rnbertahew-Fulton Conttob Co., Ful ton Sylphon Dir., *286-287 Spence Engineering Co., Ino., <389 Warren Webster A Co., *416--41? GRILLES. REGISTERS AND OR NAMENTAL METAL WORK (Scr Looser*, iTapiifni) AJ Mfg. Co.. <344-345 Air Control Produeta, Ino., <238 Air Devices, Ine.,<155,346-341 Air Distribution Produeta, *339 Air-Factors, Ine,, *243 Auer Register Co-, The, *246 Barber-Caiman Co., *347,271 Carnes Carp., <348-349 Dole Valre Co.. The, <420 General Electric Co., <83-83 Hart A Cooley Mfg. Co.. *250-251 American Blower Dir. of American- BeQ A GoaaeW Co.. *383-383 Bmks Mfg. Co., *178 Davis Eogsnemng Corp., *385 Dole Refrigerating Co., *194 Drayer-Hsssoa, Dir. of National-U. 8. Radiator Corp-, *78 . r>nfihm.Pni>il Ine., *406. 409 - li Air Conditioning Corp., *80 -__ Floor Produeta Go., A Dir. of The Fluor Corp-, Ltd., *179 General Fitting* Co., *336 International Boiler Worka Co^ The, 349 Kiliebrew Engineering Corp., *887 Mario Ceil Co., *88 MeQuay, Ine., *133-133 Mueiler Braaa Co., *434 __ National Heater Co., Ino.. <124-125 National-U. S. Radiator Corp., Heating A Air Conditioning Dir., *325-327 Patterson-Kelley Co., Ino., The, *191 Recold Corp., <96-91 Richmond Engineering Co., Inc., <388 Taco Hrotmilne.. <393 H. A. Thrush A Co., *396-391 Trane Co-, The. *136-139 Western Blower Co., *224 Wrstingbouse EleetoeCorp., Sttzrterant Div., *176. 225 Edwin L. Wietaod Co., <146-147 Worthington Corp, Air Coad'g A Bo * frigeration Dir., <95 York Corp-. Sub. Bnrg-Waraer Corp., 96 York-Shipiey, Ine., <380 Yula Corp..^formerly Yula Water Heat- HEAT PUMPS Acme Industries, Ine., <64-65 Addison Produets Co., <97 Lennox Industriee, Ine., *109,123 Mmaijcesutic Ctoo..,. Iidnuc., Tihne, <-110 Trane Co., The, <136-189 HEAT SURFACE AeroSn Caro., *186-187 _ AsMrican Btewu. Dir. of American- Standard, *66-69 GAO Mfg. Co., The, *190 D. J. Murray Mix. Co., *13$ John J. Nesoittilne., *142 New York Blower Co., *216 Niagara Blower Co-t *87 Richmond Engineering Co., Ine., *888 Rittling Corp., The, *193 Warren Webster A Co., *416-417 Edwin L. Wiegand Co- *146-147 Young Radiator Co., *143 HEATERS, Automatic Hot Water, Domestic Bryan Steam Corp., *344 - Carlin Co., The, *371 - Crane Co., *333-333 Hydrotherm, Ine., *848 8. T. Johnson Co.. *874-375 National-U. S. Radiator Corp., Heating A Air Conditioning Dir., *325-827 Peerless Heater Co., *330-83! Petto, *376-379 - Ray Burns Co., *377 Raypak Co., Ine., *353 HEATERS. Blast . Aerofin Corp., *186-187 Aeroveut Fan Co., Ine., *197 .American Blower, Dir. of AmericanStandard, *66-69 Barley Blower Co.. *200 M. Blazer A Son, *93 Carrier Corporation, *74-75, 130 Dunham-Busb, Ine., *406-409 - Electromode, Dir. of Commerrial Con trols Carp., *144 GAO Mfg- Co., The. *190 Industrial Engineering A Equipment Co., *145 Mario Coil Co.. *86 MeQuay, Ine., *133-133 D. J. Murray Mfg. Co., *135 Herman Nelson, Dir., Ameriean Air Filter Co., Ine., *126-129 Niagara Blower Co., *87 Trane Co., The. *136-139 Weatx Electric Heater Co., *148 ' Weatingbouse Electric Corp., Sturte- rantDir., *235 Edwin L. Wiegand Co., *146-147 Yoong Radiator Co., *118 HEATERS. Cabinet Airtberm Mlg. Co., *330 American Blower, Dir. orf Amorioan- Staadazd, *66-0 Carrier Corporation, *74-78, 130 Dunham-Bush, Lon., *406-409 Etaetromode, Dir. orf Commercial Con trols Carp.. *144 0g Electric Ventilating Co., *134, 314 Kritzer Radiant Coils, Ine., *311 MeQuay. Ine., *182-133 Herman Nelson, Div_, Ameriean Air Fil ter Co., Ine., *126-129 John J. Nesbitt, Ine.. *142 . Rattling Corp., The, *193 Tram Co.. The, *138-139 Wesix Fhirtrir Heater Co., *148 Edwin L. Wiegand Co., *148-147 Young Radistar Go., *143 CAGES. Liquid Level Henry Valre Co., *274 Moeuv Bras Co., *424 GAGES. Pretnuie ' . General Controls, *273-273 Ja*. P. Marsh Corp-a *423 Kritser Produeta, A Dir. of Peeriees of Am--4ra^ Inc.. *103 Krueger Air Conditioning Carp., *256 LcuBlower Co., *212-213 -Pjrfo-Netioual Co., Tbe, Multirent Dir^ 2S7 Titue Mfg.Corp., *Insert Section Tuttle A Bailnr, *358-359 United States Register Co., *260-381 GAGES. Vacuum Ja*. P. Marsh Corp., *423 MoeBs Instrument Co-, *2S3 gasburners A Heat ing Dir., *316-319 Babeoek A WtlosxCo^ The, *339 Dura-Vent Ccrp,, affiKww. of Peeries* Mfg. Dir. of Dorm Corp., *368 Gordon-Piatt, luo., *369 . Industrial Combustion, Ino.. *373 Lennox Industries, Inc., *109, 133 Mettlm Co., Ine., The, Dir. of Eclipse Fori Eugrg. Co., *376 Natioaal-u. B. Radiator Corp., Heating _ A Air Conditioning Dir., *226-327 Oit A Sembower, Inc., <351 Peonsylrani* Furnace 4 Iron Co., *111, HANGERS, Radiator NatkjnaJ-U. S. Radiator Corp., Hrstiwg A Air Conditioning Dir., *325-837 HEADS. Exhaust , . V. D. Anderson Oo.. The.Dtr. orf In tonations! Basic Economy Corp., 404-405 Muekle Mfg. Co.. *235 Acme Industries, Ine., *64-65 Adseo Dir., Yuba Consolidated In dustries, Ine.. <296 Aeroo Corp,, *381 Aerofin Corp.. *188-1S7| ' HEATERS, Air Aeroveut Fan Co., Ine., *197 Air Device*. Inc.. *155. 246-341 American Foundry A Furnace Co., 104-105 Buffalo Forge Co., *301 E. K. Campbell Cos *U6 Caapbell'Heating Co.. *114-116 Chicago Steel Furnace Co., *117 Draro Corn., *118 ' Bectrtunodo. Dir. of Commstial Con trol* Ccrp., *114 Industrial Engineming A Equipment Co., *145 Jackson A Church, Dir. of York-Ship- Icy, Inc.. *119 Johnson Heater Corp-, *126-131 Lareo, Ine., *108 Lennox Industries, Inc., *109, 123 MeQuay, Ino, *133-123 Mammoth Furnace Oo., The, *133 Mario Coil Co.. *68 National Heater Oo-, Inu, *134-126 National-U. 8. Badratnr Corp., Heating A Air Conditioning Dir., *325-327 Herman Ndsoa Dir., Ameriean Air Filter Co., lau, *126-129 Rittling Corp., The, <193 - Thermobloc Dir., Prat-Daniel Corp., 128 Tjemlund Mfg. Co., *127 Trane Co., The, *136-139 Wesix Electric Heater Co., *148 Westinghonse Electric Carp., Sturta- raatuir^ *22S L. J. Wing Mfg. Co^ *146-141 HEATERS. Duct Campbell Heating Co., *114-116 Cairur Corporation, *74-75, 130 Chicago Steel Furnace Co., *117 Draro Corp., *118 Bteetromooa, Dir. orf Commercial Con trols Corp., *114 Hayes Furnace Mfg. A Supply Co., 106-107 Industrial Engineering A Equipment Co.. *145 Jackson A Church, Dir. of York-Ship- Icy, Ine., *119 Johnson Hosts Coro., *120-121 Industries, Inc., *109,123 Mammoth Furnace Co_ Tbe, *123 National Heats Co., *124-125 ' Tjsnlund Mfg. Co., *127 Weeix Electric Heats Co., *148 HEATERS. Electric Electromode, Dir. of Otanmsaal Con trols Corp., *144 Industrial Engineering A Equipment Co., *145 - Herman Nelson Dir., American Air ni ts Co., Ino, *126-129 Trade-Wind Motarfans, Ine^ *323 Wesix Electric Heats Co-, *148 Edwin L. Wiegand Co., *146-147 HEATERS. Feed Wats Adseo Dir., Yuba Consolidated In dustries, Inc., *296 Beil A Gossett Co., <382-383 Daria Engineering Corp., *385 Please t~--1vUw THE GUIDE 1959 when writing to Advertisers  16 1959 Guide Pattereoo-KeDey Co, Ine, Tbe, *191 HiduDood &fi|iaafifi| Co, lac., *S8S Wereen Webster A Co., M16-417 Worthington Corp, Air Condg. ft Re frigeration Dir., *85 Yula Carp., formerly Yula Water Hasten, uc., *393 HEATERS. Pud Oil Adseo Div, Yobs Consolidated In dustries, Ine, >390 Bell ft Goeeett Co., 483-383 Campbell Hating Co., *114-115 Cyclotberm, Dir. of National-U. S. Radiator Corp., 445 , Davis Engbwenng Corp., 485 Draro Corp., *118 General Fittings Co., *385 Industrial Engineering ft Equipment Co., *145 Jackson ft Church, Dir. ol York-Shin- Wy, Ino, *119 Johnson Hester Corp., *130-131 Killehrew Engineering Carp., *387 Mammoth Furnace Co., Tha, *123 National Baler Co., Ine, *134-12$ Pattenoa-Kelley Co., Ion., The, *191 Richmond Engineering Co., Inc., *3S8 Taco HeatersTlne, *393 H. A. Thrush ft Co., *390-391 Titusville Iron Works Co, The, Div. of Strathera-WaU* Corp., *353 Tjernlund Mfg. Co., *137 Edwin L. Wiegand Co.-, *145-147 Wilson Engineering Corp., *380 HEATERS. Gas E. K. Campbell Co.. *115 Campbell Heating Co., *114-115 Chicago Steel Furnace Co., *117 Cyclotberm Dir. of Natiooal-D. S. Radiator Corp., *345 Draro Corp., *118 Hayes Furnace lffg. ft 8uppty Co.. 105-107 ' Jackson ft Cbureh, Dir. f York-Ship ley, Inc.. *119 Johnson Heater Corp., *120-131 Lennox Industries, foe, *133 Mammoth Furnace Co., The, *133 National Heater Co., Inc., *134-135 Herman Nelson Dir., American Air Fil ter Co.. Ine, *138-139 Thennobloc Dir., Prat-Daniel Corp.. 135 Tjemhjnd Mlg. Co., *137 Westinghouse Eleetris Corp., Sturto- vant Dir., *325 HEATERS, Hot Water Service Aoco Corp., *381 Air Devices, Inn., *155, 340-341 Aldrich Co., *337 Bell ft GoomU Co., *388-383 Bryan Steam Carp., *344 . Burnham Corp., -334 . Carlin Co.. The, *371 Crane Co., *333-333 Cydntherm Dir. of National-U. S. Radiator Corp., *345 Daria Engineering Corp., *385 Oeneral Fittings Co., *385. J. T. Johitsoa Co., *374-375 Johnston Bros., Inc.. *350 Killebinw Engineering Corp.. *387 Natioaal-U. 8. Radiator Corp., Heating ft Air Conditioning Dir., *325-337 Phttenon-Kdley Co., Inc., The, *191 Peerless Heater Co, *330-331 Kirptk Co, Ian., *353 BWtmond Engineering Co., Inc., *333 ' H. B. Smith CoT. Inc., The, *333 Taco Heatoa, Ido., *393 Titusville Iron Works Co., The, Dir. of 8ttuthas-WeQs Corp., *353 WeU-Melnia Co., *335 Yula Corp., formerly Tula Water Heaters. Inn., *393 uyMSS, IJB.J Aeroo Corp., 431 Aerofin Cerp, *185-187 American Tuba Product#, fno, *384 Bell ft GoesettCo, *383-383 CwnpheTl Co., *114-115 General FtttiaesOo, *386 KSlebtww F.ngrncrring Corp., *387 Fattersca-KeSsyCoTli >`191 Tooo Heaters, Inc., *393 H. A, Thrush ft Co., *390-391 York-Sbipley, Ino., *380 Yuls Corp., formerly Yula Water Heat ers Inc., *393 HEATERS, Space, Direct-Fired American Foundry ft pyroses Co.. 104-105 Campbell Co., *11^115 Chicago Steel Furnaee Co.. *117 Dravo Corp-, *118 Jackson ft Church, Dir. of Yak-SMp- ley, Ine, *119 Johnson Heater Carp., *130-131 I^nwar Industries, Inc,, *133 Mammoth Furnace Co., lie, *133 National Heater Co., Inc., *134-135 Thermobloc Div., Prat-Daniel Corp., Tjcrntund Mfg. Co., *137 Vapor Heating Cerp, *354 Yark-Shiptey, Inc., *380 HEATERS. Storage Adseo Div. Yuba C dustries, 100., *296 Davis Engineering Corp., *385 Central Fittings Co., *385 Killebrew Engineering Corp., *387 Pattenoa-Kelley Co., Ine., The, *191 Richmond Engineering Co., Inc., *388 Taco Heaters.-Ine, 493 Yula Corp., formeny Yula Water Heat ers, Ine., *393 HEATERS. Tank Adseo Dir., Yuba T*. dustries, Ine., *298 Aerco Corp., *381 Bril ft Gossett Co., *385-383 Dinner-Haneon^Inc, Dir. of National- *78 General, Fittings Co., *335 Indnstrud^ Engineaing ft Equipment Killebrew Engineering Carp., *387 Fsttason-KeUey Co, Ino., The, *191 Peerless Heater Co, *330-331 Richmond Engineering Co., Ino., 4*9 Werix Electric Heeta Co., *148 Edwin L. Wiegand Co., *145-147 ' Yula Corp., formerly Yula Water Heat ers, Ino., *393 HEATERS, Cult Aerorent Fan Co., Ino., *197 American Blower, Dir. of American- -foundry ft Furnace Ox, 104-105 Buffalo Fargo Co., *203 Burnham Corp., *334 Campbell n*"t Co., *114-115 Coma Corporation, *74-75, 130 Chicago Steel Furnace Co., *117 Clarage Fan Co., *76, 305 Crane Co.. *333-333 . Draro Corp., *118 Dunham-Bush, Inc., *406-409 Feddezs Corporation, *131 Haj^e^Fumace Mfg. ft Supply Co., Ilg Electric Ventilating Co., *134.814 Jackson ft Church. Dir. cf York-8hiD- ley, Ino. *119 Johnson Heater Corp., *120^131 Kritsa Products, A Dir. of Peolms of America, Inc., *103 Kritsa Radiant Coils, Ine., *311 Larco Inc., *108 Lennox Industries, Inc., *133 Mammoth Furnace Co., The. *133 MeQuav, Ice., *133-133 Mario Coil Co., *85 Mtickle Mlg. Co., *335 D. J. Murray Mfg. Co., *135 National Heater Co., Ino., *134-135 Natioaal-U. 8. Radiator Carp., w-- ft Air Conditiooiug Dir., *335-837 Herman Nelson Dir., Amoiean Air Filter Co.. I~~, *125-139 John J. Nesbitt, Inc., *143 New York Blower Co., *215 . Niagara Blower Ox, *87 Riming Carp., The, *193 Sheldons Engineering Ltd., *339 Thermobioc Dir., fret-Daniel Corp., *135 Trane Co., The, *135-139 Warren Webster ft Co., *415-417 Western Blower Co., *224 WeetingbooBS Electric Carp., Starte- rant Div. *325 Edwin L. Wiegand Co., *146-147 Wilson Engineering Corp., *360 L. J. Wing Mfg. Co., *140-141 Young Radiator Co., *143 Crane Co., *333-323 General Electric Co., *85-63 Johnson Heata Corp-, *130-131 Kntsa Product, A Div. of Feaiw rtf America, Ine., *103 Lennox industries, Inc., *109, 133 Majestic Co., Inc., The, *110 National Clay Pipe Mfgra, Tim, 414- HEATERS. Unit, Electric Electromode, Div. of Commerrial Con trols Corp.. *144 Ilg Elsctrie Ventilating Co., *134, 314 Weeix Electric Heata Co., *148 Edwin L. Wiegand Co., *146-147 L. J. Wing Mfg- Co., *140-141 NationaLD. 8. Radiator Corp., n-tin4 Air Conditioning Div., *325-337 Peateas Heata Co., The, *330-331 Pennsylvania Furnace ft boo Co., *111, Edwin L. Wiegand Co., *146-147 York Corp., Sub, Borg-Warna Carp., HEATERS, Unit. Gas Fired Aerovent Fan Co., Inc., *197 Airtherm Mfg. Co., *330 American Blower, Dir. aCAmerims- Btandsrd. *55-59 American Foundry ft Furnaee Co.. 104-105 Burnham Corp-, *334 Campbell Heating Co.. *114-115 Carrier Corporation, *74-76,130 Chicago 8teri Furnace Co., *117 Dravo Corp., *118 Dura-Vent Corp., Affiliate of Peer^s Mlg. Div., cf Dover Corp- *358 Fodders Corporation, *131 Hayes Furnace Mfg. ft Supply Co, 105-107 g Electric Ventilating Co., *134,314 Jackson ft Church, Div. of Yort-Ship- ley, Ino. *119 Johnson Heata Cory., *130-121 Lennox Industries, ino., *123 Mammoth Furnace Co., The, *123 National Heata Co., Ine, *134-125 National-D. S. Radiator Coro-, Hating ft Air Conditioning Div., *325-337 Herman Nelson Div., American Air Fil ter Co., Inc., *125-129 John J. Nesbitt, lac., *143 Tbe11rm0 obloo Div., Prat-Darnel Corp., Trane Co., The, *135-139 Warren Webster ft Co, *418-417 Wmtingbouae Electric Corp., Sturtevant Div., *325 L. J. Wing Mfg. Co., *140-141 HEATERS. Unit, OU Fired Airtherm Mfg. Co., *320 American Foundry ft Furnaee Co. 104-105 Campbell Heating Co., *114-115 Chicago Eteri Furnaee Co., *117 Dravo Corp., *118 JackaonA Church, Div. of York-Sbio- ley, lac.. *119 Johnson Heater Caro, *120-131 Lrnnoi Industries, Ine.. *132 Mammoth Furnaee Co., The, *133 National Heata Co.. Inc, *124-125 Thermobloc Div., Prat-Daniel Corp., Trane Co., The, *138-139 HEATING DUCTS. Under Concrete Floor Slabs (5m Daet*. Under Con crete Floor SZofce) HEATING EQUIPMENT, Air. Heavy Duty ' American Foundry ft Furnace Co 104-105 ' E. K. Campbell Co., *116 Campbell Heating Co., *114-113 Chicago Steel Furnaee Co., *117 Dravo Corp., *118 Johnson Heata Corp., *120-131 Lesnox Industries Ino., *106,122 . National Clay Pipe Mtgn, The, 314- York-8hipley. Ine., *380 HEATING EQUIPMENT. Auto- mafic Airtemp Div., Chrysler Corp., *98-99 Airtherm Mfg. Co., *320 American Foundry ft Furnaee Co. 104-105 American Blower, Div. of American- Standard, *55-59 Amoican-Standard, Kewmnee Boiler Div., *338 ' American Standard, Plumbing ft Heat ing Div., *318-319 B. K. Campbell Co., *116 1 Campbell Heating Co., *114-115 Carlin Co., Tlw, *371 Chicago Steel Furnace Co., *117 Columbia Boiler Co. of Pottstown, 449- Crane Co.. *333-323 Dravo Corp., *118 Dunbam-Buab, Ine., *405-409 Federal Boiler Co., *346 Hydrotherm, Inc., *348 . Illinois Engineering Co., Div. of Ameri can Air Filta Co., Inc., *418 Jackson ft Cbureh, Div. f York-Ship- ley, Ine.. *119 Johnson Heata Corp., *120-121 8. T. Johnson Co., *374-375 Lennox Industries, Inc-, *109, 123 Majestic Co.. Inc., The, *110 Mammoth Furnace Co., The. *133 National Heata Co., Inc., *134-125 National-U. 8. w*d;to* Cerp., Heating ft Air Conditioning Div. *325-327 Peerless Heata Co.. *>330-331 Pennsylvania Furnaee ft Iron Co.. Ill, 332 Pbtro, *375-379 Ray Burner Co., *377 Tbermobloo Div., Frat-Danid Cap.. *125 Titusville Iron Works Co., The, Div. of Strathas-Wells Corp., *353 Trane Co.. Tbe. *135-139 Weil-McLaia Co., *335 York-Sbipley, Ine., *380 HEATING EQUIPMENT. Coal Fired American Foundry ft Furnace Co. 104-108 American Blower, Drv. of American- Standard, *65-49 . American-Standard, Kewanee Boiler Div., *338 American Standard, Plumbing ft Hat ing Div., *315-319 K K. Campbell, Co., *116 Campbell h--*;-* Co., *114-115' Columbia Boiler Co. of Pottstown, 443 343 Crane Co., *323-323 Lennox Industries, Ine-, *109, 133 Majestic Co., Inc., The, *110 National Heata Co., Ine., *124-125 National-U. 8. Radiator Corp., H*ri*j ft Air Conditioning Div., *335-337 Peerless Heata Ox, The, *330-331 National Heata Co., Inc., *134-125 Nstional-U. S. Radiator Corp. Heating ft Air Conditioning Div., 325-337 Ray Burner Co-, *377 Thermobloc Div., Prat-Daniel Corp. HEATING EQUIPMENT. Air Real- HEATING EQUIPMENT. Electric Electromode, Div. of Commercial Con trols Corp., *144 Industrial Engineering ft Equipment Co., *145 Majestic Co.. Ine., Tbe, *110 Wait Electric Heata Co., *148 ' Edwin L. Wiegand Co., *145-147 HEATING EQUIPMENT. Furnace . Airtemp Div. Chryiler Corp., *58-69 Airtherm Mfg. Co., *320 Numerals following Manufacturers' Names refer to pages In tbe Catalog Data Stctlim Index to Modem Equipment *17 American Foundry 4 Furnace Co, E K*ChmpbeQ Co, *11* Campbell lleSjng do., *114-115 Chki^StedFtrnmee Co., *117 Crane Co., 429423 Dimvo Corp., *u* _ General Electric Co,49- fPfrpm 4 Church, biv. f York-Ship- ley Ine., *118 8. T. Johnson Co, *374-375 Johnson Heater.Com, *1*M1 i*hm Industries. Hie, KB, 132 M.txtw, Co.. Ine.. The, *110 Nationl Cky Pipe Mvis-, The, *314- NatLnal Heata Co, Inc, *134-125 . Nationel-U. 8- Radiator Corp, Heating 4 Air Conditioning Div., *335-877 Bay Burner Co, *37? _ . , _ Tbomobkw Div, Prat-Danid Corp, 135 York-Sbipley, Inc, *380 ' Kritsa Products, A Div. cf P America, Inc., *103 Jas. P. Haiah Corp, *433 Natioaal-U. B. Radiator Corp., Heating ft Air Conditioning Div, *325-337 John J. Nesbitt, Ine, *143 Pealeo Hntg Co, The, *336-331 Pennsylvania Furnace ft Iran Co, *111, 333 Petro, *375-379 ' Raypek Co, Inc., *353 Rio-wiL, Inn., *431 Rittlinz Corp, The, *193 Sarco-aarcotnerm, *414-415 H. B. Smith Co, Inc.. Tbe, *333 Teeo Heaters, Ine., *393 H. A. Thrush ft Co, *396-391 Trane Co, Tbe. U5-139 Vulcan Radiator Co, The, *Insot See- Warren Webster ft Co, *416-417 York-6hipiey, Ine, *386 Young Radiator Co, *143 HEATING EQUIPMENT. Gas Fired Iirymn Div., Chryila Carp, *95-99 Airtherm Ml*. Co, *320 American Blower, Div. of American- Standard. *58 59 Focmdry 4 Furnace Co, 1IM-105 - Div 1 *338 Amerima-Standard, Plumbiag ft Heat ing Div, *318-319 _ ArUa Air Cooditioning Corp, *103 Bryan Steam Carp, *344 E- K. Campbell Ct>, *115 Cptnpb**ii Heating Co, *114--115 Chieago Steal Furnace Co, *117 Columbia Bc2a Co. of Pottstown, 343-343 __ Crane Co, *323-333 Diavo Corp, *118 Dura-Vent Corp-, Affiliate of Parhm Mfg. Div.of Dova Carp, *368 Federal BoOtf Co, *345 General Automatic Products Corp, *310 Ge&tfal Etoctria Co, *83-83 Hava Fumsce Mfg. ft Supply Co, *100-107 Jsciaoa ft Church, Div. of York-6hip- ley, Inc, *119 Johnson Heata Com, *125-121 twwnm Industries, Inc., *109,123 HEATING EQUIPMENT, Oil Fired Airtemp Div, Chryskr Corp, *95-99 Airtherm Mfg. Co, *320 Amoiean Foundry 4 Furnaee Co, 164-105 American-Standard. Kewanee Boiler Div, *338 American-Standard, numbing ft Heat ing Div, *315-319 Bryan Steam Corp, *344 E. K. Campbell Co, *116 Campbell Heating Co, *114-115 Cariin Co., The, *371 Chicago Steel Furnaee Co, *117 Columbia BoOa Ox Of Pottstown, 345-343 Crane Co, *333-30 Dravo Corp, *118 Federal Bouiar Co, *346 Genoal Automatic Products Corp, *310 General Elsctrie Co, *83-83 Jackson ft Chtxreb, Div. of Yttk^hip- lev, Ino.. *119 _ S. T. Johnson Co, *374-875 Johnson Heata Cap-, *136-121 Lennox Industries, Ine., *109,133 Majestie Co, Ine., The, *H0 Furnace Co, The, *95 National Clay Pipe Mrgra. The, *314- 317 . National Heaattaa Ct^o., Imnoo,,-UUV4--L1425* 8. wdt*tr Carp., Heating ditioning Div., dlS-ff7 317 National Heata Co., Inc, *134-135 National-U. S- Fdifaw Carp, H**tmg ft Air Conditioning Div, *325-837 Petto, *378-879 Ray Burna Co, *377 Tbermobloo Div, Prat-Daniel Corp, PeeriemHeataOo,The, *330-331 Pennsylvania Furnace ft Iren Co, *111, 333 Thennobloc Div, Prat-Daniel Corp, 135 ' . HEATING EQUIPMENT. Radiant Titusville Iron Works Co, The, Div, Burgees-ManidAg Co., Architectural of Btruthers-WeUs Corp, *353 Produeta Div, 409 Trane Co, The. *135-139 - L. J. Wing, Mfg. Co, *140-141 - HEATING EQUIPMENT. Steam York-Shipley, Inc., *380 ' American Blower, Div. of Ameriean- Btandard, *65-56 HEATING EQUIPMENT. High. Amokaa^taadard, Kewanee Boiler Div, 438 ' International BoDer Works Co, The, 349 Parts-Crama Co., *88 TitueviBe Iron Wake Co, The, Div. of Stnithezs-Wdle Corp., *353 American-Standard, Phimfafng ft Heat . tng Div, 418-319 Bryan Steam Carp, 444 rvJwmhU Boiler Co. af Pottstown, 443-343 Crane Co, *333-823 Dunham-Bush, loo.. *405-409 HEATING EQUIPMENT, Hot Water Durant Insulated Pipe Co, *429 Air Devices, Ine., *155, 346-341 Durant Insulnted Pipe Co, Ine., *439 American-Standard, Kewanee Boiler Federal BoOer Co, 448 Div, *338 HoSman Specialty Mfg. Corp, *416-411 American-Standard, Plumbing ft Heat Illinois Engiiieoring Co., Div. of Ameri ing Div, *315-319 can Air Filta Co, Ine, *418 Bell ft Goeeett Co, *383-383 S- T. Johnson Co, 474-876 Bryan 8team Corp, *344 Jas- P. Marsh Carp, *423 Burnham Corp, *334 Nstional-U. S. Radiator Carp., Hrating Carlin Co, The, *371 ft Air Conditioning Div, 425-827 Columbia Baila Co. of Pottstown, *343- John J. Nesbitt, Ine.j*143. 343 Peerless Heata Co, The, 436-831 Crane Co, *333-323 Pennsylvania Furnaee A Iron Co. Dunham-Bush, Inc, *406-409 111. 333 Durant Insulated Pipe Co, *439 Rio-wiL Ino-, *431 Durant Insulated Pipe Co., Ine, *439 Rittliim Corp., The, *193 . Fedoal Bcakr Co, 446 Sareo-tiareotnenn, *414-415 General Automatic Products Carp, *316 H. B. Smith Co, Ine., The. 433 Hoffman Specialty Mfg. Corp, *416-411 Titusville Iron Works, Co, The, Div. S. T. Johnson Co, *374-375 of Struthas-WcOs Cap.. 453 L. J. Wing Mfg. Co, *146York-Shipley. Ino-, *380 Young Wwd>Lw Co, *143 HEATING EQUIPMENT. Swimming Pool Raypak Co, Ine., *353 HEATING EQUIPMENT. Under Concrete Floor Slabs National Clay Pipe Mfgis, The, 414- HEATING EQUIPMENT, Vacuum American-Standard, Kewanee BoQa Div, 438 ryjvmhix Boekr Co. of Pottstown, *343- 543 Dunham-Bush, Ine., *405-409 IQiAOie Engmeering Div, American Air Filta Co, Ino., *418 Jaa. P. Marsh Cerp, *433 National-U. S. Radiator Carp-, Heating ft Air Conditioning Div, 435-837 Paries Heata Co., Tha, 430-831 Sarco-Sareotham, 414-418 Warren WeUta ft Co, *418-417 HEATING EQUIPMENT. Vapor American-Standard, Kewanee Boiler Div, 438 rvJmnhU Boila Co. of Pottstown, Jas. P. Marsh Corp.. *423 National-U. S. Radiator Corp, Heating ft Air ConditioningDiv, 425-337 Peerless Heata Co., The, 430-831 Sareo-Sarootberm, *414-415 __ Titusville Inn Works Co, The, Dtv. of Struthara-WeDa Cerp, 458 Trane Co, Tbe, *135-139 Warren Webeta ft Co, *4t6-417 York-Shipley, Ine-, *39) HOSE, Flexible Dole Reftiterating Co, *1M Wiremold Co, Tbe, *259 Amonu ens* u*w, * ue. -uxr.,,1 AizMriean Brass Co, The, Amoieaa Metal Hose Div, *149 Flexunka Corp, Expansion Joint Div, 464 U. 8. Flexible MeiaOie Tubing Co, Keflex Mfg. Div, *398-303 HUMIDIFIERS Air ft Refrigeration Corp, 43 Amoiean Blowa, Div. cf Ameriean- ewKBnz, *w v* Amoiean Moistening Co., *76 ^rT,*fnnf Mmebiri* Worb, *71, 355 Babnson Co, The. *73 Bisks Mfg. Co, *m Buenaod-otacey. Ino., *73 Buffalo Forge Co, *302 Clarage Fan Co, *78, 206 Farr Co., *168-169 Maid-O'-Mkt, Ine., *413-413 Jas, P- Marsh Corp, *423 McDonnell ft Miller, Ino., *558-359 Parfca-Crmmo Co, *88 Research Products Cap., *173 Trane Co, The. *138-139 Viking Air Products. Div. of National- U- S. Radiator Carp., *223 Walton Laboratories, Ine, *94 HUMIDIFIERS. Central Plant Air A Refrigeration Carp., 43 Amoiean Bknrar, Div. of Arberican- Standard, *65-59 American Moistening Co., *70 Ai-rnatenn* MaeMna Workx, *71, 355 Bab'nwm Co., Tbe, *72 Bayley Blowa Co, *290 Buensod-Stecey, Ine., *73 Buffalo Forge Co, *203 Please meotloa THE GUIDE 1959 wben writing to Advertisers Carrier Corporation. *74-75, ISO Clarage Fan Co, *76.305 Fare Co., *168-159 Johnson Service Co, *375-977 Mario Coil Co, *88 Jas. P. Marsh Corp., *433 McDonnel ft Milla, Ine., 458459 Niagara Blow Co, *87 Parm-Crama Co., *88 Powas Regulatv Co, The, *284-28$ Research Prodaets Corp, *173 Trane Co, Tbe, *135-159, Westingbouse Eleetrie Corp, Sturto- vantDiv, *176 HUMIDIFIERS. Industrial American Moistening Co, *76 Armstrong Machine Works, *71,156 Bahnaon Co, Tbe, *73 Binks Mfg. Co, *178 Maid-O'-Mist Ino., *413-413 Farks-Cnma Co, *88 Research Products Corp, *173 Walton laboratories,'Ine, *94 HUMIDIFIERS. Spray Amoiean MaisteningCo., *70 Babnson Co, The, *73 Blnka Mfg Co, *178 Tymm Industries, Ine., *169,133 Maid-O'-Mist, Ine., *418-413 Parks-Cnma Co, *88 Walton Laboratories, Ine, *94 HUMIDIFIERS. Unit Buffalo Forge Co.. Fare Co, *158-159 Mario CoS Co, 45 D. J. Murray Mfg. Co, *138 Niagara Blowa Co, *67 Research Products Corp, *173 Trane Co, The, *138-139 Walton Laboratories, Ino, *94 . HUMIDITY AND TEMPERATURE CONTROL ' ' a Moistening Co, *76 g MachineWorka, *71, 256 V, The, *72 a Co, *247,371 Bueasod-ocaeey, Ine, *73 . Deaoxnntie Proxiact*, Inn, *77 Dryoimatie Corp., *79 Dunham-Bush, Ine., *409-469 Hagan Mfg- Co, *449 Johnson Qervioe Co., *176477 Merooid Corp, The, *2 . ^ Minneapofo-HoneyweB Regulator Co, 176,281 Penn Controls, Ine, *283 Powas Raulsta Co., The, *384-385 Walton iMoratorim, Ino., *94 Wbite-Rodgo* Co, *196 HUMIDITY RECORDERS AND IN DICATORS Amoiean **-->*-->y Co., *76 Barber-Column Co, *347,771 Johnson Service Co, *375-377 Minn**pnlCa-Honeywell Begulata Co, 170. 281 Moeller Instrument Co., *283 Walton Laboratories, Ino., *94 Witoolator Co, *291 ' HYGROMETERS (Sm Bomtfitf Recorder* oaf loiieoton) Tniwo,* Testing laboratories, Ine., *375 Moclla Instrument Co, Ine, *233 Walton Laboratories, Ine, *94 INDUCED DRAFT COOLING TOWERS (Sts Ceettay Tower*. Forced Dreft, MecAeaical Draft) Baltimore Aircoil Co., Ine., *177 Binks Mfg. Co., *178 Index to Modem Equipment >19 NOZZLES, Oil Burner Monarch HI*. Week*, Ine., *188 OH, BURNER MOTORS 0m Meter*, Electric) OIL BURNER TUBING. . JterfMe (5m Tubing, FlesibU, MctoOte) OIL BURNERS ^S^Sstandard. Plumbing * Heat- inf 0iT, *>I8-S19 Bryan SteamOorp, *344 gj&ffiSrf&Soi *>- jtflttyr Co., Ins., Tbe, Dit. of Eciipen LeFnuneolxEInngSrgt.oCios.., l*a37p5, *109. 122 Natkmel-U- S. RdW Ooro., Heatln* A Air Conditioning Dit, *323-827 Prtro, *578-379 Ray Bares Co., *377 Burner On., *370 Lgrrnm Industrie*, Ine, *109, 123 , Nataonal-U. S. Radi*tor Cent., Heating & Air-Cooditkming Dit, *3X3-337 Fiofie Steel Bailer Dir., Nitinnal-U. 8. Radiator Corp., *320-329 Petto, *378-879 Bay Burner Co-, *377 OIL BURNING SYSTEMS, Indus trial CarlinCo., The, *371 Enterprise Engine A Machinery Co., fob. of General Metals Carp., *372 8. T. fo^nyr. Co., *371-375 Mettle* Co., lac., Tbe, Dir. of Eclipse Foal Engrg. Co., *376 Petto, 378-379 Ray Burner Co., *377 York-Shipley, Loo., *380 OIL TANS. GAGES 0mOagm, Toni) ORIFICES. Radiator Dunham-Bosh, Ine, *406-409 , ntinne* Encinesing CO, Dit. <f Amrri- sn AhPilts Co.. Ine, *118 Warren Wefasts A Co., *418-417 . PIPE COVERING (See Cosria# Ftps) FITE. Fabricated Bnor Product* Co, A Dit. of Tbe Floor Carp, Ltd, *179 PIPE FITTINGS (She Fitting*, Pipe) PIPE. Gas Vent Amerivest, A DiT. of American Metal Product* Co, Ine., *388 Dura-Vent Corp, Affiliate of realm Mlg. Div. of Dots Carp, *388 Hart A Cooley Mfg. Co, *280-281 MeUlbstos Dir, William WaOaee Co., 388-387 PIPE HANGERS (See Hangers, Ftp*) PROCESS HEATING UNITS Air Darios. Ine, *188,240-241 *-*--**" Bkrws, Dit. of A. BtundardfjtP) O Trane CoJTbe. *138-139 Edwin L. Wiegand Co, *146-147 L. J. Wing Mfg. Co, *140-141 PRHO*C*HEnS^S*H*EaATING UNITS. FluidAdsoo Dit, Yuba Consolidated Indus tries, Inc., *298 American Blows, D1t. of Astcrieaa- iiaoo vo.. ine, *uo-ia* Edwin L. Wiegand Co, *148-147 PSYCHROMETBRS 0m Air Ms Testing laboratories, lac, *278 Moeller Instrument Co, *233 Parka-Crams Co, *88 OIL BURNERS. A Aldrich Co, *337 ___ . . Amerkea-Standaid, Plumbing * Hew ing Dit., *913411 . c-ru= c*,TM*;5'_, ______ ^ ORNAMENTAL GRILLES 0mDtfimttea Grills, QriZIs, Registers end Onto* mental Metal Wank, Leaser*, Register*) - gL*1 Automatic Products Corp, *310 Oordon-Piatt, Inc., .*30 Industrial Combustton, Inc, *373 S. T. Johnson Co., *374-378 ; W"*tTM Bros., Ine, *3M , _ ,, Mettkr Co., Inc, T"i C*r- <d Eclipse Fuel Enara. Co., *378 , Natieasl-u.B. Radiator Corp-, Heating A Air Conditioning Dir, *328-327 Orr A Sembows, Inc., *381 Petro,*578-379 __ Ray Burner Co.. ST7 Sonner Bams Co-, *370 York-Shipley, Inc-, *380 OIL BURNERS. Aldrich Co.. *337 Babcock A WOccrCo.,The, *339 Carlin Go., Tbe, *371 Columbia BoOer Co. of Pcttetown, *343- >13 __ Crane Co., *328-823 . General Automatic Produets Carp, *310 Gardon-Piatt, Inc., *309 Industrial Combustion, Inc., *373 8. T. Johnson, Co., *374-375 t^m* Industries, Inn., *109,122 Mettler Co., Ine, Tte, Dir. of Eclipse Fuel Emcrg. Co, *878 - NatjocaTu. 8. Radiator Corp., Heating A Air Conditioning DIt., 328-327 On A Sembows, Inc., *351 Petto, *378-879 Ray Burner Co, *377 R******** Burner Co, *370 York-Shipley Ine., *388 Titus Mlg. Corp., *Insert Section PANEL KEATING Airfloor Co. of California. *313 Crane Co, *322-323 Edwin L. Wiegand Co, *148-10 PANELS. Air Distributing Airfloor Co. <rf California, *318 Pyle-National Co-, Tba Multi-Vent Dir, *257 PANELS, f-*t"g (See CriKag. FUndr) Tito* Mfg. Carp, insert Section PERFORATED METALS A-J Mfg. Co, *344-243 Air Device*, Inc, *188,140-241 Aas Resists Co, *248 Hart ACoofey Mlg. Co, *280-281 Bendriek Mlg. Co, *233-253 ' Pyle-National Co, Tbe Multi-Vent Dit, *187 Unitea Stats Register Co, *289-281 OIL BURNERS. Rotary 8. T. Johnson Co, *374-378 Johnston Broa, Inc., *350 Petto, *378-379 Bay Burner Co, *377 Ycrk-Shipley Ine., *380 . OIL BURNERS. Steam Atomfxlng Babcock A Wilcox Co., Tbe, *339 Mettler Co., Inc, The, Dir. of Eclipse Fnd Engrg. Co, *378 OIL BURNERS. Variable Capacity Enterprise tt*|i** A Machinery Go, Bub. of General Metals Carp, *372 Ray Burns Co, *377 York-Shipley, Ine, *380 PILOTS, Safety General Control*. 273-273 Wbito-Rodgsa Co., *290 PIPE. Bros American Bras Co, The, *180-151 Mucfls Bras Co, *424 Reading Tube Corn, *188-189 WolTsine Tube, *163-183 OIL BURNING EQUIPMENT Airtemp Dit, Cbryels Corp., *98-99 - Carlin Co, The, *371 ; fcntgpiISC A M*^,Tn*i* Co, fob. of General M*mU Carp, *373 . General Electric Co, *83-33 - . Americanly Co, Tbe, *180-181 Mueller Bras Co, *434 Reading Tube Corp, *188-189 Wolverine Tube, *183-188 - PUBLICATIONS Amsiean Artisn, *487 American Society of Refrigerating Engi- PIPE SUPPORTS. For Underground Goadalts Adseo DiT, Yuba Consolidated Indas- tties, Ine., *298 Durant Insulated Pips Co, *429 . Durant Pipe Co, Ine., *4X3 H. W. Ports A Co, Inc, *430 Reid Hayden, Ine., *430 Rie-wiL Ine., *431 U. S. Flexible IdetaOic Tubing Co., Kc- flex-Matw-MIg. DiT, *298-303 P***"t A Air Conditionini Contractor, 488 H*tay, Piping and Air Conditinning. 467 Industrial Pres, *488 Journal of Pfaimbing-Hraling A Air Conditioning, The, *488 Snipe Mgripe, *4M PULSATION CONTROL Industrial Aooustica Co, loo.. *438 U. S. Flexible Metallic Tubing Co, B> flcs-Pulsco-Mfg. Dit, 296403 PIPS, Vitrified day. Heating Dueta National Clay Pipe Mlxa, Tbe, *314-817 PUMP MOTORS 0m Meter*. Electric) PUMPS. Ammonia Worthington Carp, Air Oondg. A Ra- irigsation Dir, *98 PNEUMATIC CONTROLLERS (Sm Controller* and Control Equipment. BUetrie) PRECIPITATING EQUIPMENT DoUings Corp, *168 Electro-Air Cleans Co, Ine., *168 Trion, Ine., *174 WstzngbousElectric Corp., Sturtemnt DiT, *178, 228 PREFABRICATED DUCT CON NECTORS 0m DuetCmmmtm, ProJabrimUi) PREHEATERS, FUEL OIL Adsco Dir, Yuba Consolidated Indus* tries, Ine., *298 Gcnssl Fittings C -, .. KUlebre* Engineering Corp., Taco Heater*, Inc, *393 H. A. Thresh A Co^ *380-391 Westers Blows Co.,*224 Edwin L. Wiegand Co, *148-147 PUMPS. Boils Feed ' Bufialo Pumps, *394 . Chicago Pump Co, fob. Pood Maehin- sy A Chemical Corp., *396-397 Cone Co, *321-323 Domstio Pump A Mfg. Cm, *398 Dunham-Bosh, Ine, *400-409 Bpenalty Mix. Corp., *410-411 Nash Engineering Co., The, *388-339 Roy B. Both Co, *inst Beetion Btadmore Carp, *403 Sterling. Ine, *389 . , ._ Worthington Corp, Air Condg. A Be- frigsstiaa Div, *98 PUMPS. Brins Buffalo Pomps, *394 . Chicago Pump Co, Sub. Food Machin ery A Chemical Corp., *398-397 Domeetio Pump A Mlg. Carp.. *385 Perries Pump Dir, Food Machinery A Chemical Cmp, Boy B. Roth Co, *inast Section Worthington Corp, Air Condg, A Be- irigetation Dir, *88 PUMPS. Centrifugal Bell A Gossett Co., *383-383 Buffalo Pumps, *394 - Chicago Pump Co, fob. Food Machin ery A Cbenucal Corp., *398-397 Domstio Pump A Mlg. Corp, *389 Danham-Bosh, Ine, -408-409 Hoffman Specialty Mlg. Corp, *410-411 Pksae oeodoo THE GUIDE J9S9 when writing to AdTstlss*  20 1959 Guide Kruisal Co^ Inc., . ______ " ~ THv., food Machinery A \*umuwm* Mrp., *401 Skidmore Cera. *403 Taeo Heaters, 1d&, *392 Worthington Corp., Air Condg. A Re frigeration Div., >95 PUMPS, Qreulatlnff (Sm Circulator*) Beil AGhnHC^&M Buffalo Anapa, *tbl PURGERS. Refrigeration Armatrasx MachineWorhp, *71.158 Mueller Ban Co., *434 PURIPIERS AND SCRUBBERS, Air. Goa usd Steam V. D. Aedersoa Co., The Dir. of Inter national Baaie Eeonamy Corp., *484- Trace Co-, The, 138-139 Tuttfe A Bailey, *388-289 Vulcan Radiator Co., Tbe, *naert Sec tion Warren Webster A Co., *418-417 Weeix Eleetrio Heater Co^ *148 York-Gbipley, lac., *380 Young Radiator Co., *H3 RADIATION. Cast-Iron Burnham Corp_ <324 Dunham-Buao, Ino.. *408-409 Fedden Corporation, *131 National-!}. 8. Radiator Corp., Heating A Air Conditioning Dir., *325-337 Shav-Perkina Mia- Co.. *311 Warren Webeter A Co., *418-417 Wed-MeLain Co^ *338 Young Radiator Co., *143 Chicago Poop Co., Sub. Food Machin ery A Chemical Cora. **M-*37 Domeetio Pump * Mix. Corpn *395 Dunham-Bueh, loo., *408-409 Hoffman Bpecnltjr Mix. Cora. *418-411 Krabri Co., In*. Tbfc*00 Pru lm Pump Dir., Food Maehiitery A Chemical Corp.. *401 ' Roy E. BothC<, .Insert Section Taco Heater*. loo,, *3S3 H. A. Thro^i * Co., *398-391 TuthiS Pump Co., *403 Worthington Carp., Air Condg. A Ro- fngeratiaa Dir., *95 PYROMETERS. Portable and StnlyitraSTlarting Laboratories, <375 Minneapolia-Hotieyweil Regulator Co., m, 281 QUADRANTS. Damper Dura-Dyne Carp., 268-267 RADIANT COOLING Buigese-Mmnjung Co., *389 Fupt Dir., MueUerxniat Irrigation Co., tog Div,, *318-11$ D. J. Murray kffg. Co., *135 National-U. 8. Radiator Corp., Heating A Air Conditir ' --Div., C32-5--3--37 Weil-MacLaLn C RADIATION, Copper Airtberm Mfg. Co., ^tO * ' Bmu, Dir. ef American ------------------ Plumbing A HeatiBgDir,, *318-819 RECEIVERS, Air International BoQsr Works Co., The, 349 Joy Mfg. Co.. *210-311 Rmhnwwd Engioeeriaf Co^ Ine., *388 Wortfaioxton Carp., Air Condg. A Re frigeration Dir., *95 Co_m-i rttoPump A Mlx. Corp.. *285 uuaaua*DiaB, ilia, *408-409 Hoffman SpetialtyHIg. Corp., *410-411 Naah Enginreim* i'ng "Co~ "The. **r*o----8--9--9- Peerless Putmmp Dv_ Food Machinery k Chemical CCo..rp,..,, *401 Roy B. Roth Co, losert Section "~ i. *414-415 iW PUMPS, Foe) Od Kraiaal Co., Ine^ The, *400 Ray Bursar Co., *877 Tuthill Pump Cfc>^ *403 PUMPS. Hydraulic Kraiaal Cosine., The, *400 TuthiQ Pump Co., *403 PUMPS, Lubrication Rratsel Co., Ine., The, *400 TuthBl Pump Co^ *403 PUMP-MOTOR, Combination Kraieri Co^ Ine^ The, *408 TuthiQ Pump Co., *403 RADIANT HEATING Airfloar Co. of California, *313 Tlnrxrm Mannim Co.,*309 Burnham Corp., *224 Campbell Heating Co., *114-115 Crane Co., 323-323 Electromode Dir. of Commercial Con trols Carp., *144 Kritser Radiant CoQe, Ine., *311 Natioaal-U. S. Radiator Carp., ff**ting A Air Caoditkming Dir., 325-337 BtypA Co., Ine.. *363 Serootherm Controls, Inc.. *418-415 Shew-Perkin* Mfg. Co., *313 Thermobloo Dir., Prat-Daniel Corp.. 139 Weil-McLein Co., *335 Weaix Eleetrio Hester Co., *148 Edwin L. Wlegand Co., *145-147 RADIATION. Aluminum American Blower, Dir. of American- Standard, *88-89 American-Standard, Plumbing A Heat ing Dir., *318-319 John J. Neebitt, Inc., *141 Sbaw-Peridna Mfg. Co-*313 Vulcan Radiator Ch, The, Insert Seo- Trana Co., The, *135-139 Wileon Engineering Corp-. *360 Young Radiator Co., *143 Dunham-Bueh, , ^0445 Fedden Corporation, *131 O A O lOg- Co,, The, *190 Gdneml Automatle Produeta Corp-, *310 Rittlin* Cecp-Tbe, *193 Shew-ArkiiwMIg. Co., *3U Tsene Co-, The, *138-139 Volean Radiator C&, The, *Inaert Seo- RADIATION, Plain, Extended Sur face American Blower, Dir. of American- Standard, *66-89 riiint, ^ Inn, *408-409 Fedden Corporation, *ui GAO Mlg. Co., Tbe, *190 GeneralAutomatic Products Cerp^ *310 Kritoar Produota, A Dir. < Peerieas of America, Iaa^ *103 Kritser Radiant Cotb, Inc., *311 National-U. 6. Radiator Corp- ti-g A Air Conditioning Dir, *335-337 Kittling Corp-, Tbe, *193 Sareo-Sareotoenn, *414-415 8haw-Ferkna Mlg. Co., *313 H. B. 8mitb Co^Ino^ Tbe, *333 Trane Co., Tbe, *1M-IM Vulcan Radiator Co., Tbe, *Inavt See- Warren Webeter A Co., *416-417 RECEIVERS. Condensation . Domestic Pump A Mlg. Corp., *395 RoyE. Roth Co., *eeert Section Worthington Corp., Air Condg. A Re frigeration Dir., *95 RECEIVERS. Refrigerant*' Acme Industries, Ine., *84-65 Worthington Oorp., Air Condg. A Re frigeration Dir., *95 York Carp., Sub. Bocg-Warner Carp., RECORDERS. Humidity. Tempera* tore Amerimo Motstenlng Co., *70 Barber-Cotman Co., 147, 371 Johnson Service Co., *378-377 Minneapolis-Honeywell Regulator Co., 179, SSI Moeller Instrument Co., *383 Power* Regulator Co., The, *284-28$ REFRACTORIES, Cement. Materi als Armstrong Cork Co., Building Material! Dir., *444 Babcock A WQeas Co., The, *839 Philip Carey Mix- Co- The. *448-447 REFRIGERANT DRIERS (5M Dri- PUMPS, Sump Buffalo Putspa, *384 Chicago Pruummpp Ccoo_^Bbouob. F*ooooad MMeachoin- st k Chemical Cora, *4M-41l riirrlnm Pump Div., Food Machinery A Chemical Corp., *401 Skidmore Corp., *403 RADIATION, Baeeboard, Femme American-Standard. Plumbing A Heat ing Dir., *318-319 Crane Co., *338-333 Dunham-Buah, Irw^ *408-409 Fodders Corporation, *131 Kritaer Radiant Ceils, Ine,, *311 RADIATION. Underfloor Airfloar Co. of Califorsin, *313 National Clay Pipe Mfm, The, *314-317 REFRIGERANTS 11.13, Z2.113, U4A PUMPS. Transfer, Belt-Driven and Direct Connected Kraiaal Co., Ian, The. *400 PenUm Pump Dtv,, rood Machinery A Cbemkal (W, *401 Roy B. Both Co., *Iaamt Section Natioaal-U. S. Radiator Corp. Heating A Air Conditioning Dir,, *335-337 RitUieg Corp-, Tbe, *193 Sorcothenn Orntrob, Ine., *414-415 Bbaw-Ptrione Mfg. Co., *319 H. B. Smith Co-Tino^ Tbe. *333 Tnuae Co., Tbe, *138-139 RADIATOR ENCLOSURES AND SHIELDS National-U. 8. Rndistor Corm, H**^f A Air Conditioning Dir., *335-327 S&rco-Sareotherm, *414-415 REFRIGERATING EQUIPMENT. Abeorptkm Carrier Corporation, *74-75,130 TutbQl Pump Co., *403 ato Pump Co., Bub. Food Ma _y A Chegiml Corp.. *396-397 Roy E. Roth Co., Insert Section Skidmore Cora, *403 PUMPS, Vacuum Chicago Pump Co., Sub. Food Mechin- gy A Chctniral Cora *398-397 Domeetio Pump A Mix. Corp., *388 Hoffman SBorialty Mlg. Carp., *410-411 Kmissi Co., lno.,The, *400 Nash Engineering Co., The. *398-399 Sereo-Sercotberm, *414-418 Skidmore Cora.. *403 Warthinxton Cup., Air Condx. A Re- frixetatian Dir., *98 PmtUm TMw tfiwwl Chemical Oorp., *401 Roy B. Roth Co., Inert Section a Vutaan Radiator Co., The, *Inscrt 8eotion , Weil-Melais Co^ *338 Weeiz Eleetrio Heater Co., *148 RADIATION. Baseboard Noofer- Amaricaa-Stondard, Plumbinx A Heat ing Dir., >318-319 Columbia Boiler Co. of Pottetown, *343343 Dunham-Bueh, _ *408-409 Feddere Corporation. *131 G *0 Mix. Co., The, *190 General Automatic Produeta Cora. 310 Kritser Produeta, A Dir. of Pecricaa of America. Ino^ *103 Kritaer Radiant Coilfl. Ine., *311 National-U. 8. Radiator Carp., Beating A Air Conditianinx Dir., .325-327 loba J. Nesbitt. Inc., *143 Kittling Corp., Tbe, *193 Sarcotaerm Controls. Tnc., *414-415 RADIATOR HEAT REFLECTORS Oorp., Sub. of Borg-Wanmr. 453,456 RADIATORS. Ctibfnet Airtberm Mfg. Co., *320 Plumbing A Heat ing Div., *318-319 Dunbem-Bush, Inc-, *408-489 Feddss Corporation, *131 Nstiooel-U. B. RadiatorCorp., W**ti* A Air Conditioning Dir., <433-827 Kittling Corp., The, *192 Shaw-Pmkme MfgTCo^ *313 Weil-MeLain Co., *338 Edwin L. Wiegand Co., *148-1(7 Young Radiator Co., *113 RADIATORS. Conrraled Airtberm Mlg. Co.. *330 Flumbijig A P--*ing Dir., 318*311 Ameriean Blower, Dir. d Ameriean- Standard, *68-89 Bell A Gemett Co-, *383-883 Cerrica Corporation, *74-78,130 Trane Co., The, *138-139 n Worthington Corp^ Air Condg. A Re frigeration Dir., *95 York Omp^ Sub. Borg-Werner Corp., REFRIGERATING EQUIPMENT. Steam Jet _ Worthington Corp., Air Condg. A Re frigeration Dir., *95 REFRIGERATING MACHINERY Acme Industries, Inr-, *84 85 Addison Products Co^ *97 Brunner Dir., Dunham-Bueh, Ine., 408-409 . Canter Corporation, *74-75, 139 . Curiae Mfg. Co., Rebigaretian Dir., *193 Drayer-Hanson, Inc., Dir. of National- U. 8. Radiator Corp., *78 Numerals following Manufactures*' Nausea refer to pages In tbe Q*ntog Data Section Index to Modem Equipment >21 . Koeoy rower wj., i w, -> Trane Co., The, *138-139 Worthington Corp., Air Condg. A Ro(rigeretion Dir., *95 York Corp., 8ub. Borg-Werner Corp.98 REGULATORS, Gas General Controls, *273-273 Leslie Co.. *278 Maxitml Co., *279 REFRIGERATION CONTROLS Aleo ValveOo., loo., *370 General Contreb, *373-273 Mereoid Carp The, *280 Minoeesolu-noaeyWeU Regulator Co., 170, 231 peon Contrets, Ine., *283 Ranen Ine., *288 White-Rodgere Co., *290 REFRIGERATION TUBE. Copper (Jit* Tube* and Tubing, Copper) REGISTERS (3m OrUla, Refitten and Omanunlal Mctei Work) A-J Mfg. Co- *244-245 Air Control Products. Ine.. *238 Air Deriees, Inc., *155.240-341 Air-Factors, Ine., *3(3 Auer Register Co., Tbe, *246 Barber-Caiman Co.. *247,271 Carnes Corp., *348-349 Dole Valve Co.. The, *420 General Eleetrio Co.. *83-83 Hart A Cooley Mix. Co., *750-251 Hendrick Mfg. Co.. *253-253 IsdependeutRegister Co.. Tbe, *255 Krueger Air Conditioninf Oorp., *258 LauBlower Co.. The, *213-213 National-U- S. Radiator Oorp., Heating A Air Conditioning Div.. *325-327 Prte-National Co., Tbe, Multi Vent Dir., *257 Titus Mfg. Corp., .Insert Section Tuttle A Bailey, -758-259 United States Register Co., *280-261 Universal Diffuser Corn., *284 Wetorioo Register Co.. Ins., *285 Young Regulator Co., *283-283 REGULATORS. Air Volume A-J Mfg. Co., *244-345 BarbcrGolman Co., *347,271 Duro-Dyne Corp., 266-287 Hart A Cooley Mfg. Co., ISO-251 Krueger Air Conditioning Corp., *2S6 Pincers Regulator Co., *284-285 Watte Regulator Co., *428-427 Young Regulator Co., *263-263 REGULATORS. Pressure Aerco Corp., *381 Ateo Valve Co., *270 Bell A Gossett Co., *382-383 A. W. Cash Valve Mfg. Carp., *419 General Controls, *272-273 Hoffman Specialty Mfg. Corp., *418-411 Johnson Service Co.. *275-277 leslie Co., *278 Jea. P. Marsh Corp., *423 Mazhro! Co., *279 Mereoid Cora, Tbe, *280 MinDeepoiia-HoneyweU Regulator Co., 170 281 . Penn Controls, Ine., *283 - RoberUhaw-Pultoa Confaols Co., Ful- tim-Sylpboo Div., *285-287 Sareo Co-. Iaa. *414-415 SpesoeEngmeeringCo., *289 Strong. OarliaSa A Hammond. *435 H. A/Thruah A Co., *390-391 Watts Regulator Co., *425-437 REGULATORS. Remote Control Atco Valve Co., *270 Leslie Co., *278 Mereoid Oorp-, The, *280 Robotohsw-Fulton Controls Co., Ful- ton-Sylpboti Div., *286-287 8penee EngineeringCo., Ine., *289 Wbtte-Rodgas Co., *290 Young Regulator Co., *262-283 RELAYS, Electrical and Pneumatic Merooid. Cora, The. *288 Minneapolis-Honeywell Regulator Co., 170,281 Penn Controls, Ine., *283 RELIEF VALVES (Sm Votes, Belief) RESTRICTOR TUBING (Ste Tubing, tOernebey-Cbeaey Co., *161 Dollinger Carp., *165 Dunhem-Buen, Iou, *408-409 Strong, Gari'nl* 5 Hammond, *425 SEPARATORS, Duet American Air FilterCo., loo., *158-160 American Blower, Div. of American- Standard. *86-89 V. D. Anderson Co., The, Div. of Inter national Basic Economy Carp., *48448S Dollinger Cara, *165 George Evans Corp., The, *167 Farr Co-, *168-169 SEPARATORS. Gas V. D. Anderson Co., Tbe, Div. of Inter national Berio Economy Oorp-. *404- y Co., *161 SOUND ABSORBERS Industrial Acoustics Co., Ine., ttt Elof Harrison, Ine., *435 - United Sheet Metal Co., *268 SPRAY EQUIPMENT Beyley Blower Co., *208 Bril k Coeeett Co., 333-383 Binks Mfg. Co., *178 Monarch Mfg. Works, Ine., *165 SEPARATORS. Oil Acme Industries, Inc., *64-85 Air-Hase Corp., <157 Dollinger Corp., *165 Kraaw Co., Ine., Tbe, *400 Recold Ccrp-, *w-81 York Corp., Sub. Borg-Werner Corp., American Moistening Co., *70 April Showers Co., ine., *458 Rahnson Co., Tbe, *73 Binks Mfg. Co., *178 Buffalo Forge Co., *203 Fanjet Div., MueUermist Irrigation Co., Fluor Produeta Co., A Div. of The Fluor Corp., Ltd., *179 Lilie-Hoffman Cooling Towers, Ine., SEPARATORS, Steam Adsco Div., Yuba Consolidated Indus tries, Ine., *299 V. D. Anderson Co., The, Div. of Inter national Basie Economy Carp., *484- national Basie Economy Corp., 484- SHEETS. Asbestos, Flat sod Corru gated Jonns-ManviQe, *450-451 Mariey Co., Tbe, >183 Monarch Mfg. Works, Ine., *185 D. J. Murray Mfg. Co., *135 Parks-Crsmer Co., *88 Phillips Cooling Tower Co., Inc., *184 ' SPRAY NOZZLES American Moistening Co., *70 April Showers Co., Iae., *458 Behnaon Co., The, *72 Binks Mfg. Co., *178 Buensod-Stacey Ine., *73 Buffalo Forge Co., *202 Fanjet Div., MueUermist Irrigation Co.. 459 Mariey Co., The, *183 Monarch lug. Worfcz, Ine., *185 D. J. Murray Mig. Co,, *135 Parks-Cramer Co., *88 REGULATORS. Back Pressure Aleo Valve Co., *270 Spence Engineering Co., Inc., *289 REGULATORS. Damper A-J Mfg. Co.. *244-245 . Barber-Colman Co., *247. 271 Duro-Dyne Corp., *286-287 field Control Div., of H. D. Conker A Co.. *232-293 Simplex lug. Co., 2M Spence Engineering Co.. -m* Trane Co., The, 138-183 - United Btales Begtaer Co., *268-281 Young Regulator Co., 282-283 RINGS. Welding Tube Turns, Div. of Chemetron Corp., 307 ROOF COOLERS ' April Showers Co.. Ine., *458 Fanjet Div., Muellermist Irrigation Co., 459 REGULATORS. Draft Field Control Div., of H, D. Conkey A Co-, *293-293 Simpin Mfg. Co., *295 SAFETY VALVES (See Faber, Safttg) REGULATORS. Evaporator PresAloo Valve Co., *270 REGULATORS. Feed Water McDonnell A Miller. Ine., *358-359 Spence Engineering Co , Ine.. *289 REGULATORS. Furnace - . Field Control Div. oi H. D. Conkey A Co.. *292-293 Mereoid Corp., The, *280 Penn Controls. Inc., *283 Simplex Mfg. Co., *295 White-Rodgers Co., *290 SEALING TAPE. Duct mad Insula tion Duro-Dyne Corp., *288-267 SEPARATORS, Air ' V. D. Anderson Co., Tbe, Div. of Inter national Basie Economy Corp., 404- American Wanning A Ventilating Co., The, *226 E3go Shutter k Mfg. Co., *227 ID Electric Ventilating Co,, <134, 214 . Herman Nelson Div., Ameriean Air Filter Co., Inc., *158-150 Reed Unit-Fans, Ine., *218 United States Register Co., *260-261 L. J. Wing Mfg. Co.. *148-141 STEAM GENERATORS. Unit Babcock k Wilcox Co., Tbe, *339 Columbia Boiler Co.of Pottetown, *242- 343 Cyclotherm Div. of National-U. iS. Ra- diator Cora, *345 Fitsgibbons Boiler Co., Inc., *347 Orr A Sembower, Inc., *351 Titusville Iron Warm Co., Div. of Struthers-Wdla Cora, *353 Worthington Crap., Air Condg. A Re frigeration Div.. *95 York-Shipley, Inc., *388 STEAM HEATING SYSTEMS (See Hfating Sftteme, Steam) STEEL INSULATION (See Initiation. Sted) STOKER MOTORS (See Motor* Elec tric) SKYLIGHTS. Insulated Owens-IQinots, *441 Pittsburgh Corning Corp., *442 STOKERS. Mechanical. Bltumi- Crane Co.. *323-323 WhiUy Co., Inc., *361 WiU-Burt Co , The, *362-363 - 317 SMOKE DETECTORS AND INDI CATORS (For flue* and Duett) STRAINERS. Air Combustion Control Div., Electronics ifaid-O'-Mist, Ine., *412-413 Corp. of America, *294 Muriler Steam Specialty Co., Inc., *357 B'" 1 ilis-Honeywril Regulator CSop.,ence Engineering Co., Ine_ *289 Watte Regulator Co., *425-427 Plesae mention THE GUIDE 1459 when writing to Advertlese  22 1959 Guide STRAINERS, Dirt V. D. Anderson Co., The, Dir. of Inte- Bmm Economy Corp, 406 105 Armstrong Mlrilill Wort*, *71, 856 HoffmanSpecialty Mtf Carp-, *410-411 IUinaM Engineering Oo, Dir, American Air filter Co-, Inc-, HIS Krahri Co., Imx. The, *400 Monarch MIg. WarkaTlnc, *185 Mueller Steam Specialty Co., Ine, *357 &MfcrTco;HlW17 STRAINERS. Gn# _ _ , V. D. Anderson Co., Tbe, Dir. of Inter national Bode Economy Corp., H- 406 Armstrong Machine Works. *71, 856 Co., *378 Maid-O'-Mbt, 2no., 413413 UimQct 8team Specialty Co., Ioe., *357 STRAINERS. OU _ V. D. Anderson Co., The, Div. of Intcr- Baste Economy Corp., HOI Armstrong Machine Works, *71, SS6 BeU A Garnett Co , *589-383 Krairol Co., Ioe., The. 400 Monarch MU- WorkaTlne, *185 Mueller Btcem Specialty Co., Inc., *357 Sterling. Inc., * Ales vaire vos *< Henry Valrs Co, *274 Maid-O'-Mist, Inc., H18-413 STRAINERS. Steam Aloo Valve Co, *270 V. D. AndersonCo.,The, Div. of Inter national Baaic Economy Corp., 404 Ar4m05stroog ****My Worka, *71, 356 Cmne Co-, *328-323 Dnnbam-Busb, Ioe.. *406-409 , _ HSuBt Engineering Dir., American Air Flits Co., Inc., H18 Kraiast Co., Inc., The, *400 l--Co.. *278 . at..nr Steam Specialty Co., Inc., *357 Saroo Co., Inc., <414-416 Spence Engineering Co., Inc.. <289 Stating, Inc.. *389 Strong. Carlisle A Hammond. *425 Trane Co.. The, *138-138 STRAINERS, Water Alec Valr* Co., *870 V, D. Anderaoo Co.. The, Di*. of Inter- Mtionel Baaie Economy Corp.. *404- 4SS Armstrong Machine Worka, *71, 356 A. W. Gmb Valve Mfg. Corn. H19 Dnnham-Buah, Inn, 408409 -- . -- jjinj XHt., Amenean Air Filter Co.. Inc., H18 Kraiml Co.. Inc, The, H00 LmlteCo, *278 Kaid-O'-Mist, Ine, H18-412 Monarch Ufg. Works, Imx, *185 Moeller Steam Speaalty Co., Ine, *3S7 Saroo Co-. Ine., *tl^415 Spence Engineering Co, Ine., *289 Sterling lnc, *389 TraaeCo, The. *136-129 Watts Regulator Co., *440-441 SWITCHES, Float aw. Valve Co-, *870 MeDonneD A kfiOer, Inc., *156-359 Merted Corp.. The. *280 SWITCHES. Pneumatic Johneoo Service Co., *276-277 Minnrapnlii Hnrifiyrtfl Regulator Co., .170,281 Power* Regulator Co.. The, *284-28$ General Control*, *(78-273 TANK COILS (See CeOe, TfeU) TANK HEATERS (See Heater*. Toni) TANKS. BJow-aS International Boiler Worka Co., The, *348 _ Richmond Engineering Co., Inc., *3SS American Tube Producte, Inc., *384 TANKS. Storage Richmond Rwgiexwing Co., Inc.. *388 Western Blower Co., *224 ______ r__ ______ _1 Regulator Co., 170, fai PPetnnrneraCoRnetrgoullsa,toInr Cc,o.*,2T0he, *284-285 Ranee Inc., *288 Robcrtahaw-F'ulUn Controll Co-, Ful- ton-Sylphon Dir., *386-287 Sarco-fiareotberm, *414-415 Weaix Electric Heater Ox, *148 WUte-Rodgen Co, <290 Edwin L. Wiegand Co, *146-147 Wdcnfetor Co, The, *2S1 . TIME SWITCHES (See Swiletea, Time) TOOLS. Sheet Metal Duro-Dyne Corp., *266-267 WUj-Burt Co., The, <368-863 TRAPS. Air V. D. Anderson On., The, Dir. of Inter national Pwwwy Corp., lOi- RiS Armstrong Machine Worka, *71,356 Sarco Co., Irex, *414415 Strong, Carlisle A Hammond, *425 TRAPS. Steam V. D. Anderson Co., The, Dir. of Inter national Basic Economy Corp., *404405 Armstrong Machine Works, *71, 356 Crane Co, *323-323 Dunham-Bueh, Ine.. *406-409 Hoffman Specialty MIg. Corp., H10411 Illinois Engineering Dir., American Air Filte Co., Inc,, H18 Jss. P. Marsh Carp., *423 Sarco Co., Ine., *414416 Sterling, lnc., *389 Strong, Carlisle A Hammond, *425 Trane Co.. Tim, *126-129 Warren Webster A Co.. H16417 TRAPS. Thermostatic V. D. Anderaoo Co., The, Dir. of Inter national Baric Eeoooay Corp., 4M405 Crane Co., *328-323 Dunham-Bueh, Inc., *406409 Hoffman Specialty 6Hg. Corp.. HI041I miaoca Engineering Dir., American Air Filter Co., Inc., HIS TEMPERATURE control Aereo Corp.. *281 Berber-Cwnan Co, *247, 271 Combustion Control Dir., Electronlea Corp. of America, <294 Dunham-Bush, Inc.. *406-409 General Controls, *278-273 liiiiwu* Engineering Dir., American Air FUtcr Co., Inc., H18 lUinoia Teating laborstorim, Inc., *275 Johnson Seirice Co., *276-277 Leslie Co., *278 Jan. P. Marsh Carp., *423 Mated Corn., <280 Minneeootia-HooeyweQ Regulator Co., 170.281 Powai Regulator Co.. The, *284-283 Ranco Inc., *288 Robertahaw-Fultnn Control* Co., Ful- too-Sylphon [Mr., *286-287 Sareo-Seroothom, *414-415 Spence rnriiurring Co., Inc., *289 Warren Webster A Co., 419417 Watte Regulator Co., *426-427 Wnnx Electric Heater Co., *148 White-Rodger* Co., *290 WUteator Co,The.*291 Young Regulator Co., *203-283 THERMOMETERS. Distance Type Illinois Tearing Laboratories, Inc., *275 Jaa. P. Marsh Corp., H23 Minaeapolh-Honeywell Regulator Co., 170,281 Moeller Instrument Co.. *282 Powers Regulator Co., The, *284-285 THERMOMETERS. Indicating Illinois Testing Laboratories, Inc., *275 Johnson Denim Co., *276-277 Jaa. P. Marsh Carp., *422 Minneapolis-Honeywell Regulator Co., 170,281 Instrument Co., *288 Power* Regulator Co-, The, *284-285 THERMOMETERS. Recording Johnson Service Co., *276-277 Minneapotis-HoneyweU Regulator Co., 170,281 Moeller laetrumeat Co., <282 Powers Regulator Co., The. *284-285 THERMOSTATS Barfaer-Cotmaa Co , <247. 281 Combustion Control Dir. ^ Corp. of America, *294 Central Controls, *278-273 Johnson Service Co., *176-177 Leslie Co.. *278 Mereoid Corp., The, *280 TRAPS. Bucket V. D. Andexaon Co., The, Dir. of Inter national Basie Economy Carp, 404 405 Armstrong Machine Works, *71,2SS Crane Co, *328-323 Huffman Specialty Mfg. Corp, *410-411 IlHncts Engineering Dir., American Air Filter Co., Iocx, H18 Jaa. P. Marsh Corp., *433 Sarim Co-, Incx, *414-416 Strong, Cartiale A Hammond, *425 Trane Co.. The, *126-139 TRAPS. Float V. D. Anderson Co., The, Dir. at Inter national Basic Bm--y Corp., 404 406 Armstrong Machine Worka, *71, 356 Crane Co., *329-323 Dunham-Bueh, Incx, *406409 Hoffman Specialty MIg. Corp., *410411 Jaa. P. Karsh Corp., *423 Saroo Co., lot, *414415 Strong, Carlialo A HiumbH, *425 Trane Co., The, *136-129 TRAPS, Flout and Thermostatic V. D. Anderaoo Co, The, Dir. of Inter national Basie Economy Corp., 404- Danham-Bush, Inc., *406409 Hoffman Speaalty MIg. Corp-, *410411 Illinois Engineering Dir., Americas Air Filter Co-, Ine., 418 Jaa. P. Marsh Corp.. *423 Saroo Co., Inc , *414415 Sterling, Ine.7HS9 Strong, Carlisle A H***'*An^i *425 Trane Co.. Tim, 136-139 Warren Webster A Co,, 416417 TRAPS. Noise General Sound Control, Ine., *423 tv Haosson, Inc., *433 * Industrial Acoustics Co., Inc., *436 TRAPS. Radiator Crane Co.. *228-323 Dunham-Bueh, Ine., *406409 Hoffman Specialty Mfg. Carp., *416411 Illinois Engineering Dir., American Air Filter Co, Inc., H19 Jaa. P. Marsh Corp., 423 Saroo Co.. Inc., 414419 Sterling, Ine., *389 TraneCo, The, *136-129 TRAPS. Return Crane Co., *223-323 Dunham-Bueh, Inc.. *406409 mim** Pngituning Dir., American Air Filter Co-, Inc., HIS Sereo CoTW, 414415 Sterling, lnc.. *389 TramCo, The, *128-129 Warren Webstar, A Co., H16417 TRAPS. Vacuum V. D. Anderaoo Co., The, Dir. of Inter national Basis Economy Carp., 464406 1. 366 minors Engineering Dtr.TAmerican Air Filter Co., Ine., *418 Jaa. P. ******* Corp., 423 Saroo' Co., Ioe., 414416 Strong, Ceritsia A Hammond, 425 TUBES AND TUBING. Brass Copper Amenean Brass Co., The, *156-181 Mueller Bram Co., *424 Reading Tube Corp., *189-189 Wolverine Tube, *168-153 TUBING. Aluminum' ' American Brass Co,, The, *150-IS) Wolverine Tube, *152-153 - TUBING. Fabricated ' American Brasa Co., The, American Metal Heae Dir, *149 Wolverine Tube, *168-153 TUBING. Finned Drayw-Hanson, Dir. Nataonal-U. S. Radiator Corp^ *78 f5 Air Conditioning Corp., *80 O A O MIg. Co., the, *190 General Automatic Products Corp., *319 Kritso Products, A Dir. of Peel mim of ncvuie ******* wt*, ?-* Rittling Corp., Use, *192 Wolverine Tube, *153-153 TUBING. Flexible Resdisg Tube Com, *188-189 Wtremud Co., Tbe, *269 TUBING. Flexible. Metallic Amoiets Brae* Otx. The, *156-151 Amerimn Brass Co., Tba, American Metal Hnae Div_ *149 Flezomea Corp., Expansion Joist Dir., rals following Manufacturers' Nantes refer to pages In the Catalog Data Section i* i j M Index to Modem Equipment 23 TUBING. Insulation (5cs fnsufotiea. 7V6*af) TUBING. RESTRICTOR American Bram Co-, Tbe. *150-161 Wotverins Tube. *159-153 VALVES. Check Fairbanks Co., Tbe, 421 Hammond Brasa Works, *Insert Section Henry Valve Co., Z74 Jenkins Bros.. 422 ' MueOer Bram Co., *434 . TUBING. UrUceffuIcr Rubber B F Goodrich, Sponge Products Dtr., *448 VALVES. Comatai Rediting Crane Co.. <328-323 Jenkins Bros., 433 TURBINES pyle-National Co., The, *257 L J. Wing Mfg. Co., *149441 Wwoorruthuinnggtwoua Cv^akr*p-*.,jj"ur Condg. A tte- Irigeration Dtr., *95 UNDERGROUND PIPB CON DUITS CSm Ctdnb, Undav7vmd Apr) UNIT HEATERS CSm Htaltn, Unit) UNIT STEAM GENERATORS (Ses 5tem Gtnmlart, Unit) UNIT VENTILATORS (Sat Ventila tor#, Unit*) UNITS. Air Conditioning (Sm Air Conditvmint Unit*) VALVES. Diaphragm A. W. Cash Valve MfgTCrop-, 419 Crane Coa <328-323 General Controls, <378-373 Henry VsJre Co., <274 Johnson Berviee Co., <276-277 Leslie Co.. *278 Minneapolis-HoneyweD Regulator Co-. 170, 281 Mueller Brass Co., 424 Powers Regulator Co-. Tba, <284-286 Watts Regulator Co.. 426437 White-Rodgers Co.. *290 VALVES. Expansion Akx> Valve Co., *270 Crane Co., <329-323 Genecal Controls, <278-273 Henry Valve Co., <274 Mueller Bram Co., 434 Roberishaw-Fulton Controls Co, Ful- ton-fiylphon Div., <236-287 VACUUM HEATING SYSTEMS (Sc /fcating Syrirsu, Vacuum) VALVES. Float Alco Valve Co, *270 Maid-O'-Mist, Inc.. 418413 VALVES. Air ,r V. D. Anderaoo Co., The, Div. trf Inter MeDonneD A Miller, Inn., *358-359 Roberishaw-Fulton Controls Co, Pul nationa] Baric Economy Corp., 494 ton-Sylphon Dir, *284-885 405 __ Watts IWulator Co, 426427 Craos Co., *228-323 Desornatie Products, lnc., *77 Dob* Valve Co., The. *420 Fairbanks Co., Tbe, 421 ' Hammood Brass Works, Insert Section Hoffman Specialty MIg. Corp., 410411 Jenkins Bros., 423 Haid-O'-Misi. Ine., *418413 Jam. P. Marsh Corp., 423 VALVES, Flow Control Bril A Cornett Co-. *383-383 ' Crane Co., <328-333 Dole Valve Co, 430 Dunham-Bush, Ine., *406409 Jas. P. Marsh Cop.. 423 Minneapolis-Honeywell Regulator Co, 179,281 VALVES. Angle. Globe and Cross Rnberishaw-Fultoo Controb Co., Fulton-Syipbon Dir, *286-287 Crane Co., *322-323 Fairbanks Co., The, *421 H. A. Thrash A Co, *390-391 Warren Webstar A Co, 416417 Frick Co., *195 Hammond Bram Works, Insert Section Henry Valve Co., *374 Jenkins Bros., 433 Hudler Braes Co., 434 VALVES. Gas ..... Combustion Control Dir, Electronics Corp. of America, *294 Fairbanks Co, Tbe, 431 VALVES. Automatic Hammond Brass Works, -Insert Section Jenkins Bros, *483 Barber-Caiman Co.. *347,371 Minneapolis-HoneyweD Regulate Go, A. W. Cash Valve Mfg. Cmp^, 419 . Combustion Control Dir., Electroeics 170. 381 Penn Controls, loo., *283 Corp. of America. *294 Dole Valve Co.. 439 Whita-Rodgera Co., *290 General Controls, *278-378 Johnson Semes Co., *376-377 Lcslia Co., *378 Jss. P. Marsh Corp., 423 MeDonneD A Miller, loo.. *358-359 Minneapofis-Hoasywril Regulator 170, 281 -Co., VALVES. Gate Crane Co, *322-323 ^Fairbanks Co, Tbe, 431 Hammond Brass Works, *losert Section Jenkins Bros., 423 Muslim Bram Co, *434 Powers Regulator Co., The, *284-285 Spence Engineering Co., Ine., *269 VALVES. Humidifier Watte Regulator Cb.,'428437 .. Maid-O'-Mlst, Ine, 418413 White-Rodfecs Co., *290 MeDonneD A MDler. Ioe, *258-359 VALVES. Back Pressure AJco Valve Co., *370 A. W. Cash Valve MIg. Corp., *419 VALVES. Balancing American Tubs Products, Inc., *384 General Fittings Co., *386 Hammond Brass Works, *Inaert Section Maid-O'-Mist. Inc., 419413 oarto-Barootharm, 414415 H. A. Thrash A Co., <390-391 VALVES. Blowoff Fairbanks Co., The, *421 Jenkins Bras., *422 VALVES. By.Pass Fairbanks Co., Tbe, <421 Jenkins Bros., 422 Mueller Bran Co., 431 VALVES, Magnetic Ainu Valve Co, *270 General Controls, *878-273 McDonnell A Miller, Ioe.. *358-359 Penn Controls, Ine., *283 VALVES. Mixing. Thermostatic Dote Valve Co, *420 General Fittings Co, *386 Powers Regulator Co, The, *284-285 Robertahaw-Pulton Controls Co, Ful- too-Sylphon Div, *286-287 Saroo Co, Ine., 414415 - Watts Regular Co, 426-437 ' VALVES. Motor Operated Barber-Column Co, *347, 371 Bed A Gossett Co, *389-333 Combustion Control Dir, Electronics Corp, of America, *294 Desomatic Producta. Ine-, <77 General Controls, *372-273 Illinois Engineering Dir, American Air Filter Co, Ine, 418 Jenkins Bros., 421 Johnson Service Co-, *376-377 Mi*"***I--'*-H<`*1y-^1 Regulate Co, *170,381 _ Powers Regulate Co, The, *284-285 VALVES. Non-Return Fairbanks Co, The, 421 Hammond Bram Works, 'Insert Section Jenkins Bros.. 422 VALVES. Packless Dunham-Bush, lnc-. 406-409 Henry Valve Co, *274 Hoffman Speaalty Mfg. Corp-, 410411 Johnson Service Co, *276-277 Jss. P. Marsh Corp.. 423 MueOer Bram Co, *424 Powers Regulate Co. " Robotahaw-Fulton C------------- too-Sylpfaoa Dir, *286-287 Saroo Co, Inn., 414415 Spence Engineering Co, Inc.. *2 Steriing, Inn., *289 VALVES. Radiant Heating Hammond Bram Works, lneert Section Sarcotberm Controla, Inn., 414415 H. A. Thrush A Co, *396-391 VALVES. Radiator Crane Co, *322-323 Dote Valve Co, The, *420 Duaham-Bush, Ine., *406-409 Fairbanks Co, Tbe. *421 Hammond Bram Works, -Insert Section Hoffman Speaalty MIp. Corp, 410411 I Linoia Engineering Div., American Air . Filter Co, Inn, 418 Jenkins Bros-, 423 Maid-O'-Mist, Inc-, 418413 Jaa. P- Marsh Corp, 423 Nstional-U. 8. Radiate Corp, Heating A Air Conditioning Dir, *325-327 Robertahaw-Fulton Controb Co, Ful ton-Sylphon Div, *286-287 Saroo Co, Ine., 414416 Sterling, lux, *389 TraneCo, The. *136-139 Warren Webster A Co, *416-117 VALVES. Radiator. Convector Robertehaw-Fultoa Controb Co, Ful- too-Sylpbon Div, *286-287 oarner-tyoanan us., <, in Minneapoiis-HoneyweU Regulator Co, 170, 281 Robertahaw-Fulton Controb Co, Ful ton-Sylphon Dir, *386287 VALVES. Radiator Orifice Dunham.Buah, Ine., *406409 Hammond Bram Works, 'Insert Section Illinois Engineering Dir, American Air Filter Co, Ine., 418 Warren Webster A Co, 416417 VALVES. Radiator. Convector, Pneumatic Diaphragm Johnson Berries Co, *276-277 Minneapolis-HoneyweD Regulator Co, 170,281 Power# Regulate Co, Tbe, *284-285 VALVES. Reducing Bell A Cornett 00,4388-383 A. W. Cash Valve Mfg. Corp, *419 Crane Co, *328-313 Dunhsun-Bnah. Ine.. 406409 Hoffman Specialty Mfg. Corp-, *410411 Leslie Co, *276 Please mention THE GUIDE 1259 when writing to Advertiser# Robertehaw-Fultoa Controb Co, Fulton-Sylphon Dir, 286-287 Spence Engineering Co, Inn.. *289 Strong, Carlisle A Hammond. *425 H. A- Thrush A Co, *399-391 Watte Regulate Co, 436427 VALVES. Refrigerant Line Also Valve Co, *279 Dole Refrigerating Co, *194 Hammond Bram Works. 'Insert Section Hemy Valve Co, <274 Jenkins Bros.. *422 Mueller Bram Co, *434 Worthington Corp, Air Condg. A Re frigeration Dir, *96 VALVES. Relief V. D. Anderson Co, Tbe. Div. of Inter national Basic Economy Carp, 404 405 BoD A Gomett Co, <383-383 A. W. Cash Valve Mfg. Corp. *419 Dote Valve Co., The, 429 Dunham-Bush, Inc, 406409 Henry Vahre Co, *274 Jas. r- Marsh Corp, 423 McDonnell A Miller, Ine, *358-359 Monarch MIg. Worbx Ine., *185 . Mueiier Bram Co, 424 Robertehaw-Fultoa Controb Co, Ful- ton-Sylpbon Div, *286-237 Taco Heaters, Inn, *392 . H. A. Thrush A Co, *390-391 Trane Co-, The, *136-139 TuthQl Pump Co, 483 Watte Regulator Co, *426427 York Carp., Sub- Borg-Warne Corp, *96 VALVES. Safety A. W. Cash Valve Mfg. Corp, 419 Cotabastion Control Dir, Electronice Corp-, of America, *294 Frick Co, 495 General Controls, *273-273 Jaa. P. Marsh Corp, *423 McDonnell A Miller. Ine, *3S-3S9 Mueller Bram Go, *484 Watts Regulator Co, *426477 VALVES. Solenoid Aloo Valve Co, *270 Combustion Oonrinf Div, Eteetronics Corp- ef America, *294 Dob Valve Co, 420 General Controb. *273-273 Jae. P. Marsh Carp, *423 McDonnell A Miller, Incx, *338-359 Penn Controb, Ine., *283 Rsnoo Ine, *288 _Speneei Engineering CLoo, Iitne, *289 White-Rodgera Co, *290 VALVES. Tempering American Tube Products, Ine., <384 Dote Valve Co, Tbe, *420 General Fittings Co, *388 Power# Regulate Go, The, *284-285 Taoo Heats#, Ine, *3M Watte Regulator Co, 438437 Yob Corp, formerly Yula Waters, Ine. *393 VALVES. Thermostatic Aloo Valve Co, *270 Barber-Column Co, *347,871 Crane Co-, *328-323 s' General Controb, *271-273 Leslie Co, <378 Jas. P- Marsh Corp, 423 - Powers Regulate Co, Tbe. 784-285 Bobmtshaw-Fulton Controb Co, PuJ- ton-Sylpfaan Div, *286-287 Spence Engineering Co, Inn., *289 Steriing. Ino, *389 Wibobtor Go, The. *291 Yula Corp, formerly Yula Waters, Ine., VALVES. Water Flow Regulating Bdl A Goasett Co, *383-383 Dote Valve Co-. The. *480  24 1959 Guide Dunham-Buah, Ine- *406-408 *' General Controls, *273--27J Leslie Co- *778 Johnaoo Service Co-, *275-277 Mmota|d-Honeywell Regulator .Co-, Powers Regnlatcr Co., The, 2S4-2SS Rofcertafcaw-Fultcn Gantrds Co., Fal- tan-Syipfaon Div- SSV-SS? Speace Engineering Co-, *289 Sterling, Inc.. *389 Taco Heaters, Inc., >387 H. A. Thruah A Cb., >390-391 Watts Regulator Co., >426-427 VALVES. Water Lord, Float Control Maid-O'-Mut, Ino- >41-413 McDonnell A Miller, Ino., 358-859 Robertehaw-Fulton Controls Co., Ful- ton-Sylphoo Dir.,- >388-287 Watts Regulator Co., >426-127 VALVES. Water Renatating Alee Valve Co., >270 A. W. Cash Valve Mfg. Coro., H19 Dob Valve Co., #420 , Hammond Bran Works, `Insert Section W" Co., >978 - Jas. P. Hash Corp., *423 McDonnell A Milter, he-, >358-359 Penn Controls, Inc., >253_ -S^lpbc .tor Co- >426-427 VAPOR BARRIERS Philip Carey Mf*. Co., >446-447 Infra Insulation. Ine., *455 Johne-ManvOle. >450-451 L.O.F GhuaTxixn Co-. >438-439 Refieetel Corp., Sub. of Borg-Warner, 453,456 VENTILATORS. Attic (Sse Foas, BUctria, ProptlUr, Supply and Bx- IsmO Air Devices, Ine.. >155, 240*241 AtVn Coder A Ventilator, Ine., >230 AnMRcaa Blower, Dir. of Araeriran- Air Control Products, Ino., >238 . Ammerman Co., Ine., >331 Auer Rtfkter Co., The, >246 Barter-Oilman Co., >247, 271 Buffalo Force Co,, >203 Carnes Corp., *248-349 . DeBotbesat Fans Div., American Ma chine A Metals, lee., >807 . Cb&rtes Demnth A Boos, Ino., >254 Hart A Cooley Mfg. Co., *250-251 . Headrick Mfc. Co., >233-253 III,Electric Vantilstin< Co- >134, 214 Independent Register Co., The, >355. Jena Air Products Co.. Ine., >334 Penn Ventilator Co., >336 - PrepeQair Div., Robbins A Myers, Ine., 217 Read Unit-Fans, Ino., >218 Titus Mfg. Carp., (Insert Section Trane Co.. The. >136-139 United States Register Co., >250-261 Waterloo Register Co., I ,265 VENTILATORS, Laboratory G. C. Breidsrt Co., The, >239 Century Fan A Ventilator Co., Ine., >203 Jean An Products Co., Ine., >224 MucUe Mfg. Co., >235 Western Engrg. A M/g. Co., >337 VENTILATORS. Roof Aerovens Fan Co., Ise., >197 Air Devices, Ine., >155, 240-241' Aladdin Heating Corn., >199 Alien Coder A Ventilator, Inc. >230 American Blower, Div. of American- Stendard, >68-60 Am10e5rican Foundry A Furnace Co., >104- Americao Warming A Ventilating Co., 226 Ammerman Co., Toe.. >231 C. C. Breidert Co., The, *233 Brookside Corporation, >201 Buffalo Forge Co.. >203 Caroea Corp.. *243-349 Century Fan A Ventilator Co., Ine, >203 Chicago Blower Corp., >205 Ctarace Fan Co., >78,206 Cdt Ventilation Co. of Anoio, Inc., 233-229 DeBotbesat Fans Div., American Ma chine A Metals, Inc., *207 . Hizschman-Pohls Co.. Ine., >223 Hi Electric Ventilating Co., >134, 214 Jena Air Product* Co., Ine., >334 MucUe Mfg. Co., >235 New York Blower Co., >216 Peerless Electric Co-, The, >216 Pena Ventilator Co., >226 Propellair Div., Robbins A Myers, Ine., 217 Reed Unit-Fane, Ine., >218 H. H. Robertson Co-, >92 Trade-Wind Motorfans. Inc., >222 Trane Co-, The, *136-09 - Western Engra. A Mfg. Co., >237 Westinghouse Electric Corp., Sturtevant Div., >176, 225 L. J. Wing Mfg. Co- >146-141 G. C. Bnridert Co. >233 Buffalo Font Co., >203 Champion Blower A Force Co., >204 Us Eteetrin Ventilating Co., >134, 314 Ua Blower Co., Tin, >313*213 Reed Unit-Fans, Ine-*3l Torrington Mf(- Co., The, Trade-Wind Motorfaas, Ine., > LOVI^>, IUG.,a>M, Ammerman Co., Ine., >231 Q. C. Bnsdcst Co- The. >233 Buffalo Forge Co- >203 Chicago Blower Corp- >205 Pena Ventilator Co- >235 Watarn Engre. A Mfg. Co.,' >237 WestingbouseElectricCorp- Sturtevaat Div., >176. 225 L- J. Wing Mfg. Co- >140-141 VENTILATORS, Celling Buffalo Force Co- >202 Trade-Wind Motonans, Inc., >222 VENTILATORS. Fbw , Colt Ventilation Co. of America, Inc., 238-229 Propetlair Div-Robbing A'Myera, Ioc., Aerqvent Fan Co., toe., >197 VENTILATORS, Unit Aerovent Fan Co., Ine., >197 Air A Refrigeration Corp,, *63 Allen Coder A Ventilator, Ine., >230 American Blower, Div. of Amerieao- - Standard, >66-69 Ammerman Co., Ine., >231 Buffalo Forge Co- >202 Cdt Ventilation Co. of America, Inc., 223-229 DeBothezat Fane Div., American Ma chine A Metals, Ine- >207 Ilf Eleetrio Ventilating Co- >134, 214 Muekle Mfg. Co., >235 Herman Nelson Div- American Air Fil ter Co.. Inc.. >123-129 John J. Nesbitt, Ine., >142 Propellair Div., Robbins' A Myers, Ine., >217 Kittling Corp., The. >193 Trade-Wind Uotorfana, Ine., >222 Trane Co- The, >136-139 Vuleaa Radiator Co., The, >Insert 8eo- tioa Wests Eleetrio Heater Co., >148 Wertern Eogrg.Co- >237 - Waetio*bourn Electric Corp., Sturtevaat Div- >176. 225 - Edwin L. Wiegand Co., >t46-147 L J. Wing Mfg. Co;, >140-14! ' VENTILATORS, WaU Allen Cooler A Ventilator, Ine., >230 Ammerman Co- Ine., *J3l Carnes Corp., >248-249 Colt Ventilation Co. of America, Inc., >228-129 JDeun.n AVi.raP^rLo.d_u_cft.*.Co.M- CIne.. >234 VENTILATORS. Window Of Electric Ventilating Co., >134 914 Lau Blower Co- The, >213-313 VERMICULITE (See InxxleHm) VIBRATION ABSORBERS iSr* Hoand Dcodcntng) American Braes Co- Tbs, >150-151 American Braes Co- American Metal Hose Div.. >149 Ftesoniee Corp- Expansion Joint Div- 304 . . General Sound Control, >433 Owes-Coraiog Fiberghu Corp- >171,440 U- S. Flexible Metallic Tubing Co- Keflex Mlg. Div., >293-303 WASHERS. Air (Bee Air Fasten) WATER COOLING (& Cooling Equipment, Fater, CooUnt Tovteri) Acme Industrie, Ine., >64-65 Airfan Engineering Co., >198 American Blower, Div. of American- Standard. >66-69 'American-Standard, Plumbing A Heat ing Div., *318-3)9 Baltimore Airedl Co- Ine.. >177 Binks Mfg. Co- >178 Brunner Div., Dunham-Bush, Ino., 406-409 Carrier Corporation, *74-75,130 Curtis Mfg. Co., Refrigeration Div- 193 Dole Refrigerating Co- >194 Drayer-Hanson. Div. of National-UB. Radiator Corp- >78 Dunham-Busb, Ine- >406-409 Fluor Products Co- A Div. td The Fluor Corp- Ltd->179 E. D. Goodfellow, Ine., >180 Havens Coding TVrwere, Div. d Havens Structural Steel Co- >180 Kritser Products, A Div. of Peerless of America, Ine., >103 . InUe-Hoffman Coding Towers, Ine., > 182 Marley Co- The, >183 MeQuay, Ine- *122-133 Natiocni-U. S. Radiator Corp., Heat ing A Air Conditioning Div., >325-337 Niagara Blower Co- >87 Patteraon-Kelley Co- Ine- The. >191 Phillips Coding Tower Co- Inc., >184 Ready Power Co- The, >196 Trane Co- Tim. >136-139 Worthington Corp., Air Condg. A Re-, frigeratton Div- *95 . WATER COOLING. Spray Systems Air A Refrigeration Corp., >63 American Blower, Div. of American- Standard, *66-69 April Showers Co., lac- >458 Sinks Mfg. Co- >178 Fanjet Div- Muellermist Irrigation Co- WATER MIXERS. Thermo*talk: (Sit Kefs**, Tempering) American Tube Products, Ino,, >384 Bell A Gossett Co- >382-383 Dole Valve Co- The, *420 ' General Fitting* Co- >380 Powers Regulator Co- The,' >984-285 Robcrtehaw-Fulton Controls Co- Ful- too-Sylpbon Div- *286-287 Taco Heaters, Ine., >392 WATER TREATMENT Worthington Corp., Air Condg. A Re^ frigeration Div- >95 WELDING ROD American Brass Co- The, >150-151 Mueller Brass Co- >424 WHEELS. Blower Aerovent Fan Co- Ine., >197 Airfan Engineering Co., >193 American Blower, Div. of American- Standard, >66-69 Brookeida Corporation, >201 Champion Blower &ForgCo.,*204 Oarage Fan Co., >76, 206 Garden City Fan Co- >208 General Blower Co- >209 Lau Blower Co., The, *213-718 Tomngton Mfg. Co., The, >231 Viking Air Products, Dir. of National- U. a. Radiation Corp., *222 - Namerala following Manufacturers' Names refer to pages In the Catalog Data Section A . I. A . F ile N u m b e r 3 0 - J . 30f ----------------------------------------1---------------:---------------------------------:--------'------------------- ;------'--An ------- ANEMOSTAT presents a complete line of equipment for DRAFTLESS AIR SYSTEMS A. I.A. File Num ber 3 0 -d D A T A O N A N E M Principle of Aspiration The Anemostat Air Diffuser splits the supply air into multiple, separate air streams and at the same time creates low pressure areas in certain parts of diverging passageways. This causes room air to be drawn into the device where it is thoroughly mixed with supply air. Hie mixture is discharged in a series of expanding turbulent air layers and,. therefore, readily entrains a large amount of additional room air. - ' As a result, temperature and humidity are equalized throughout the room and a' continuous air motion in the occupancy zone within low acceptable velocity limits is established. Stagnant air pockets are also avoided. . Hie quantity of room air drawn into Anemostat Air Diffusers depends on the specific design, size and type of the various units and is equal to as much as 35 per cent of the supply air. Hiis effective aspiration distinguishes Anemostat Air Diffusers from all other air outlets. . ANEMOSTAT Smaller Ducts Aspiration permits the use of higher tem perature differentials and higher supply air velocities than customary, which results in savings in the initial cost of fans and ducts and in theoperating cost offans. Ductlayouts may be simplified because Anemostat Air Diffusers distribute air evenly in spite of unusual room plans, columns or other obstructions. '- Research and Engineering Anemostat Corporation of America main tains a large, well-equipped laboratory man^pd by experienced scientific and tech nical personnel for testing purposes and the development of new products. Engineers from all over the world have visited the Anemostat laboratory to witness demon ' strations of Anemostat products and their . applications to any conceivable problem pertaining to . air diffusion. Anemostat has spent millions of dollars in research and engineering and will continue to make sub ' stantial contributions to the progress of the science of air distribution. ' has a product for every air distribution heed Anemostat high induction air diffusers provide good diffusion with high temperature differential. Because supply and return ducts, fans and filters are reduced in size in direct proportion as the temperature dif ferential of the distribution air is increased, there is a definite and logical trend to use higher tempera ture differentials in both low and high velocity systems. Anemostat 100% induction air diffusers meet these needs, thus help provide vital space savings in system design. - Anemostat high velocity units are being used through the country-in many applications such as hospitals, schools, office buildings and plants. The Anemostat all-air high velocity draftless system offers many important architectural and engineering advantages. It-permits greater flexibility of design and reduces building costs because it can be used with smaller than conventional ducts. It can be installed faster. It requires no coils, thus eliminates leakage,, clogging and odors. The Anemostat all-air high velocity system has earned wide-spread accept ance because of the simplicity of its design, in stallation, control, operation and maintenance. ' The Anemostat Constant Volume Turbulator is a standardized high capacity dual duct unit handling from 800 to 7000 CFM. It provides an economical solution to many air distribution problems in which a large volume of air at controlled volume or pressure, and temperature, is involved. - With the Anemostat system, all thermal func-' tions--heating--cooling--ventilating--are accom plished with air. Coils and resultant coil lag are eliminated together with required piping. Pressure losses are low and so are noise levels. Quality-built' Anemostat Turbulators function automatically. They are easy to install, simple to maintain . ' ' . The Model 60 Anemotherm Air Meter, developed by the Anemostat Corporation of America, gives ' you--in one' convenient instrument--a simple, . rapid method of balancing and checking any air system. It puts at your fingertips, by means of colorcoded pushbuttons, air velocities, air temperature and static pressure--all vital readings you need. Model 60-Anemotherm Air Meter pays for itself on time saved on only one major job.' ' . More data available on request Send for your free copies of these valuable catalogs and bulletins MLCCTI00 HUMl m. *0 - Selection Manual #60 contains selection and application data on Anemostat Draftless Aspirating Air Diffusers for conventional, 100% induction and high velocity systems. This new catalog describes the Anemostat Dual Duct High Velocity Air Distribution for heating and ventilating schools. You will find in these pages, typical classroom layouts, performance data, control diagrams and other essential information. This informative bulletin gives vital data on Anemostat Constant Volume Turbulators for modem air distribution systems. It explains important design features, shows practical applications, contains selection and application data. imai Anemotherm Air Meter Bulletin #55 describes the most modern way to balance heating and ventilating and air- . conditioning systems. It tells how the Anemotherm Air Meter gives you all vital readings with pushbutton ease. ?Air Meter; DRAFTLESS ASPIRATING //Jl ANEMOSTAT CORPORATION OF AMERICA lO East 39th Street, New York 16, N. Y. Representatives In Principal Cities air diff users ':;ators^lJe^Ma Utemjferatl tt--. pi' > Z ' J` ^ . \. sJ V `TlgTOaimiSK jTjj! itojsf. v,t ^ > - rent-- Ji-HGOGii ` V- gdiffusersareffiecffilya 1 jqtx. -(&Mts Circular Flusb-Mounted Air Diffuser Illustrated is the Kno-Draft KOA adjustable air diffuser. The sleeve damper, together with the adjustable lower cone, permits independent air volume and air direction adjustment after installation. Constructed of light, sturdy spun aluminum. Type KOA diffusers are available in a wide range of sires from 5" to 36" neck diameter. Bulletin K-20-A. Slotted Air Diffuser Kno-Oraft Series KLS all aluminum, adjustable slotted diffusers are partic ularly adapted to board rooms, foyers, lounges and simitar spaces. The harmonious, classic lines of the extruded aluminum vanes complement any decor. These handsome units may be installed singly or butted in series to form a continuous slot for heating or cooling. Series KLS diffusers are complete with built-in air volume and air directional control. Available io lengths from 2 to $ feet; widths of 3 W and 6" for single direction air pattern, 12" for two<lirectioo air pattern. Bulletin K-27. Square Air Diffuser . The attractive Kno-Draft square air diffuser U available in two types designed for quick, easy installation -- Type KP (overlap) for flush mounting on plaster or certain acoustical ceilings -- Type KPT for T-Bar ceilings where the diffuser snaps into the ceiling construction. Both models are identical in air performance characteristics. Despite their square design air is distributed in a true circumferential pattern for. maximum effectiveness. Fabricated of pressed steel with baked enamel finish in sires 5" to 14" neck diameter. Bulletin K-27. anbury. Conn. Building 9ace is conserved with surface mounted Kno-Oraft tfiffuseis. The deep stream lined outer cone' saves inches in the ever dwindling area above the ceiling by shift ing the difuser body downward. Performance characteristics are identical with the flush mounted KDA diffuser with the further advant-. age that the deep outer' cone inhibits ceiVing smudging. Fabricated in spun aluminum in sires 5" to 18" neck diameter. Bulletin K-38. Circular Loudspeaker Diffuser Kno-Oraft single- air stream, dual-cone design ` permits the addition of a loudspeaker to the- diffuser. As shown, a loudspeaker can be mounted above the center cone allowing both the sound source and diffuser to otilire the same strategic ceiling location. Any 8" speaker may be used and a totally enclosed - baffle provides extended frequency response. Sizes 14" to 24" neck diameter with per formance characteristics end dimensions iden tical to standard KDA diffusers. . . .. An integral light' may also be provided with - Kno-Oraft diffusers (Type KDAL). ligbt fixture . units are- available in sizes 6* to 16" neck diameter with performance characteristics identical to standard KDA diffusers. Bulletin K-20-A: . kno draft Kno-Draft Series 45 Valve Attenuators ' The Series 45 Valve' Attenuator Is the result of ten years' experience in the design and application of high. velocity units. Features in corporated in its design are allimportant to the successful oper ation of high velocity systems... assuring better balanced air de livery and constantly controlled air diffusion. These are the only high velocity units with patented Helical Neo prene-Coated Spring Dampers to insure quiet operation and com plete shutoff. Constant Volume Control insures uniform air de livery at aQ mixture conditions despite static pressure fluctuations. A Manual Control option is avail able for-use when duct design permits. While all units operate quietly, a patented Sinuous Sound Baffle may be added when excep tional silencing is necessary. Series 45 Valve Attenuators are suitable for both dual and single duct sys tems. Complete information in cluding selection tables, noise specifications, and duct desip data in Bulletin K-33-A. . dorex ^.`Recovery is the conversion) lentrained odorous, raparou^^ ineitfer adding td/tobtroctii Recovery (air pmtfiatipn\tSi *"l)texhiust air. > ' Kmmssmis& ----- ------- SZVST&Mm SPtPskss^ssHx - is *?. ^y.vM' Dorex Type C Cells are perforated steel cells 24" i 24" x 8*4" deep filled with granular activated carbon. Three models provide Afferent carbon bed thickness and weight for varying applications. Capacities range from 700 to 1000 cfm at 95% efficiency. Cells are installed in sturdy supporting frames and can be designed into oew or existing duct systems with oo more engineering than standard dust fitters. Highly effective corrosion resistant coating available for industrial applications. Bulletin 108. TYPE H CANISTERS Type H Canisters lend themselves to a variety of arrangements. Mounted in multiple on supporting manifold plates they can be installed in practically any duct system regardless of space limit ations. Supplied in two types with ft" or M" carbon bed thickness, each canister will porify from 25 to 30 cfm. Standard construction is steel but stainless steel and plastic are also available for highly corrosive conditions. Bulletin 108. CONNOR ENSKEE88 CCS?SALES REPRESENTATIVES AND ENGINEERING OfftGES^ Domestic Alabama, Birmingham Arkansas, Little Rock Arizma, Phoenix - California, Los Angeles San Francisco Colorado, Denver Connecticut, Ridgefield Oistnct of Columbia Florida, Miami . Tampa Georgia. Atlanta . Idaho, Boise minis, Chicago Peoria Indiana, Indianapolis lava, West Des Moines.. testicky, Louisville Louisiana, Hew Orleans Massachusetts, Belmont M'ttktga, Detroit ' - . Grand Rapids. - Saginaw . Minnesota. Minneapolis Missouri, Kansas City Moselle St. Louis Nebraska, Omaha New Jersey,'. Orange - New YV Albany . NewYork City . . . . Port Chester . Rochester ' . . Syracuse Norik Carolina, Charlotte '. ., . Greensboro Olio, Cleveland - Cincinnati ' ~ ` Toledo Oktahnaa, Tulsa Oregon, Portland Pennsylvania, Allentown . Mecbamcstwrgt Philadelphia - Pittsburgh . Wilkes-Barre - Tennessee, Chattanooga - . Memphis - Nashville Texas, Oailas -. Roustoo Lubbock San Antonio Utah, Salt lake City . Virginia, Richmond , - Washington, Seattle . Spokane Canadian British Cduabia, Vancouver Ontario, Toronto \ . Qnebec, Montreal - . Foreign [ ; Australia,. Sydney Aostria, Wien . - Befciua, Brussels Mi, Havana : Deanurk. Copenhagen '. ''Egypt,-Cairo *: - Bgfatd, Rochester Fraoce, Paris . >. : Germany, Dortmund Italy, Milan. . Japan, Tokyo - Netherlands, Amsterdam . Pnertn Rica,- San Juan ' South Africa, Joharmesbttrg Spain, Barcelona Sweden, Sandared - . Switzerland, Zorich SIDEWALL SUPPLY REGISTERS & GRILLES, VOLUME CONTROLLERS j TITUS SUPPLY GRILLES . , 9 1 jj I , STYLE L-271 APPLICATION * SidewaQ. 2-way directional eoo- trol. Up or down. ' S-27I L-270 SidewaQ. 2-way directional eontroL Right or left. SidewaQ. 4-way control.. Up, down, right or left.. S-270. SidewaQ. 4-way. control. Right ` left, up or . down. TITUS SUPPLY REGISTERS L-274 S-274 L-275 S-275 L-276 S-276 SidewaQ, 2-way directional con trol. Up or down plus shutoff. SidewaQ. 2-way directional con trol. Right or left plus shutoff. SidewaQ. 2-way directional con trol. Up or down phis opposed action volume control. SideweU. 2-way directional con troL Right or left plus opposed action volume control. SidewaQ. 4-way directional con troL Up, down, right or loft plus, shutoff. Same as above. * L-277 S-277 SidewaQ. 4-way directional con trol. Up, down, right or left. Opposed action volume controL Seme as above. | TITUS SIDEWALL & CEILING GRILLES L-201 S-201 L-202 5-202 No. 203 No. 204 SideweQ or ceding. Heating or cooling, l-way directional air control. SidewaQ or ceiling. Heating and eoolina. l-way directional- air controL ' Sidewall or ceitiag. Heating and cooling. 2-way directional con trol. SidewaQ or ceiling. Heating and cooling. 2-way directional. Primarily where grille must be located dose to viO. 3-way di rectionaL . Ceding -- primarily in center of room. 4-way dtrecrionaL j TITUS VOLUME CONTROLLERS AG-25 In duct behind grille or at junc tion of duct and branch takeoff. AG-35 Attached to grille or tn duct be hind . grille. - ' ;" - . '< . . AG-45\} ' Attached ^ to duct behind grille , or at .junction duct and branch takeoff.' :7' . . V 2 ' ' - ill' - LOUVER: DESIGN. Airfoil.' Solid Sk- ' tion. 'Extruded alu-' LOUVER SPACING on centers. Same as above. Same as above. Sam* at above. . . Same as above: - Sam* as abovo. Santa as above. One set individually adjustable louvers parade! long dimension. . Same as above except louvers parallel to short dimension. Two sets louvers. Front parallel long dimension. Rear parallel short dimension. Individually adjustable. Same as above except front parallel short dimension.. Rear parallel long dimension. AirfoiL Solid Sec tion.. Extruded alu minum. Santa as abovo. Same as abovo. Front louvers . 1 oo centers. Same as above. Santo as above. Same as above. Santa as above. Soma as abovo. Same as abovo. Front two tats .. %" on canters. Same as above. Same as above. Same as above. Front louvers parallel long dimension. Individually adjustable. Front louvers parallel short dimension. In dividually adjustable. Front louvers paradel long dimension. In dividually adjustable. Front louvers parallel short dimension. In dividually adjustable. Two sets individually adjustable louvers. Front parallel long dimension. Second set parallel short dimension. Same as above except front set peraDel short dim. end second set -- long dim. Two sets individually adjustable louvers. Front set parallel long dimension. Second set parallel short dimension. Same as above except front set parallel short dim. and second set -- long dim. AirfoiL Curved da* sign. Extruded ahi- . muium. . * on centers. N Santa as abovo. : Same as above. ' Same as abovo; ' - Same as above. Same as above. ^ Sara# as abovo. Same as above. Seme.es above. ^ Same as abovo. . Same as above. One set radrvtduafly adjustable louvers parallel long dimension. On# set individually adjustable louvers parallel short dimension. On# set individually adjustable louvers parallel long dimension. One set individually adjustable louvers parallel to short dimension. Left end right side louvers peraDel short dimension. Center louvers . parallel, long dimension. Individually adjustabla. Left and right side louvers parallel short di mension. Center louvers parallel long di mension. Individually adjustable.(See cut.) AirfoiL Solid Sec tion.' Extruded alu minum louver. ... 20 gauge steeL . : 22 gauge rtaoL ;iyiN -.canters. I" oo cent. Prv- ' otaid. on'center. Opposed acting I" oo canter. ;. I*/*" each section. 2%" totaL Hinged for 3renter adjustability each section, le- ividueUy adjustable. . 1 Gang operation. Full open to full dosed. Blades always parallel short dimension. Double duty. - Can move from fuO open , to fuQ dosed. , Blades always ' parallel - short dimension. .- m FRAME 1/4 41 Wide beveled edge. 18 or 20 ge. stool Same as above. Same as above. Seme as above. Wide beveled edge. 16 or 20 gauge steeL Santa as above. Same as above. Seme as above. Same as above. . Same as above. Same as above. . ' DAMPER None DAMPER CONTROL None Approx. Free Area' 80% j None None None None None None 80% . j ' -1 80% .; i *0% ' . ''4' ^. 1 Multi-shutter .. spaced on lM centers. Same as above. AG-35 opposed action. Same as above. Standard lever operator. Ramov. lever available at no extra cost. Specify K.LL Removable Allan wrench operator. Same as above. 80% f.* 50% 9, 80% ' 51 -'i - 80%-:;-| Multi-shutter .. spaced on . 1** ' centers. Same as above. AG-35 opposed action. . ;.-.i Standard 1 a v e r 80% ; operator. Ramov. lever available at . - j\ no extra cost 80% >4 Specify K.LL. ' Removable Allen* 80% "Ji wrench aperator. - ^ Seme as above.' Serna as above 8o%-;:'j W"" . Wide beveled edge. . 16 or 20 gauge steel. . Same es above." Same as above. V '' ' . . Optional (See Note A) / . ' ' . . ' . ` Optional (Saa Note A) . ' ^1 ' Optional (Saa Note A) : 80%-T ' - 80%'^1 -'80%t3 -SidewaQ & Ceiling Grille nnm e 204 -- Sidewall & Ceiling Grille ih Same as above. - " ' ' ' Same as above. * Same as above. . '. . AG-25 --Volume Controller Optional (Sae Note'A) " ' . : 7"^! 80%4 Optional (See Note Aj ' . 1 Optional (Sae Note A) "^1 i ut* e AG-45 --Volume Controller e AG-35 -- Volume Controller NOTE (A) TITUS SIDEWALL & CEILING GRILLES '- Channel type. 20 gauge cold rolled; Same as above.. " v,` None ;.v- ' .*- : 'j- t- - .si - y .. Removable Allan wrench-operator.' v ' Sevaraltvpes -re-' mote, o'perators. 47 -Write'Main Off. - - m 1 Available with opposed blada damper. Specify 2015, 2025. 2035, 2045. 2a Available with mufti-shutter damper. Specify 2014. 2024, 2034. 2044. 3. Available with rear set individually adjustable . aluminum louvers. Specify 2013, 2023, 2033, 2043. ,:sf? 'i SIDEWALL RETURN -i AIR REGISTERS, GRILLES and ACCESSORIES TITUS RETURN AIR GRILLES STYLE APPLICATION RL-230 SidewalL To moteti. oD -Titus Airfoil supplies. RS-230 Somo oi above. TITUS RETURN AIR REGISTERS RL-240 Sidewall. Rotaro air phis multv . rihutter damper. ' RS-240 . Same es above. RL-241 . . RS-241 Sidowofl. Rotura olr plus op* posed action den?per. Same as above. ' . TITUS DOOR GRILLES T-700A T-700B Exhaust arid return-air-grilles for doors, weds or partitions. ' Same as above. - . ' T-800 T-800A Exhaust and return air grille for Panel Type doors. . Same et above. T-800B Seme as above. TITUS GYMNASIUM GRILLES G-l Sidewall In school gymnasiums. G*2 Some os above except has.vol- ' ' ume controller. ' v - TITUS CONVECTOR GRILLES C-2100 C-2200 C-2300 Some os above except hat muKi- ' shutter damper blades for pos itive - shut-off. " 0*2400 Seme os above except has merits* shutter domper blades for com pute shutoff. LOUVER DESIGN V Heavy steel Curv ed* -end hemmed foradded strength. Semeesebove. LOUVER SPACING 34" on center. Same as above. Blades fixed et 45* or 0* deflection. Par allel long dimension. Seme as above except poreQel to short dimension. - s 'Y Heavy steeL Curv ed ' end.''hemmed for added strength. Same os abovo. - 34" spacing in front. ' Somo os above. Some as above. Some os above. Some ei above. Front. Nodes fixed et 45* or 0*. Parallel long dimension. ' . Some" as above' except parallel to short dimension.' ' ' Front blades et 45* or 0* deflection. Par allel long dimtation. Seme os -above except parallel to short dimension. V-Shaped _ to pre vent "see thru.- Some os abovo. ' '/j" on centers. Seme as above. . Closely spaced V-shaped louvers parallel . to long* dimension. . Same as above. V-Shoped to proveint "soe thru." . 'Somoosobovo. " "" .3/16" on centers. - - .Same as above. 1 Closely spaced V-shapad louvers parallel - to long dimension. * ' ' Same as above except has frame. Some os above. Some as above. Same as above except has flange frame. ' 14 - gauge- round i edged steel blades:' . Semeesebove. ~ . 34". on centers. ' Same ei above.* Grille. face ' only. Vertical - steel support .bars on 6 inch centers. ;Grifle .face combined rith volume con- troJUr. * '20. gauge steel -- hemmed edges. . - Same as above. */j" on centers. ' Some as.above. ^Available I" blades deflected 45* on 12" centers'- or zero degrees on 6" centers. Seme as above except provided .with 134" multi-shutter damper Wades: ' 20 gauge- steel _ outside edges 1 ` hemmed. *./ Some a* above. -34" on centers.' Some as above. Available .with I" blades deflected 45* .on 12" centers, or.zero-degrees.on 6'! centers. Specify. . ' '. Same as abova except provided with fft" multi-shutter damper blades. . - TfTUS ALL-PURPOSE FRAMES NO. 115 FRAME For all Airfoil grlllas and registers. Can be installed be fore or after plastering has been completed. Frame may be imbedded in plaster. Sponge rubber gasket to prevent air leakage. Designed for use with Titus Airfoil registers and grilles only. NO. 2 STEEL ANGLE FRAME Attaches inside duct out let with metal screws. Strengthens duct edge for easier end better plaster ing. Grilles.fit inside frame. . Grille border conceals lip' of frame ipstde. . NO. 3 FRAME For installation before or after plastering. No. 3 frame is built to actual listed size. Duct openings should be ,/a" larger to ac commodate frame. NOTE THESE ADDITIONAL SPECIFICATIONS: ' A. These edded features are standard on each SUPPLY GRILLE. 1. /)" sponge rubber gasket. 2. Countersunk screwholes. 3. Attractive softone gray lacquer finish. 4. Special mullion support where louvers exceed 20" in length. B. VOLUME CONTROLLERS have standard black lacquer finish. Gaskets furnished on all AG-25 and A6-35s. Modals ere de- . * signed to fit into duct by friction. C. RETURN AIR GRILLES are made extra heavy to withstand lew sidewall abuse. Finished with standard gray softone lacquer. D. RETURN REGISTERS are made with extra heavy steel to with stand low iid*w*ll us# and abuse. Provide volume control or completf shutoff. Have gray softone prime finish. j 6" 16" 8" 18" 10" 20" 12" 24" 14" 30" For exposed ductwork or flush mounting 6" . 16" 8" 18" 10" . 20" 12" 24" 14" 30" 36" For exposed ductwork or flush mounting . 6" 14" -8" 16" 10". 18" 12": 20" :24" For exposed ductwork or ' flush mounting ' ' 8" 18" 10" 20" . >12" 24" '14': - 30" 16" ' 36" For exposed diictwork or .flush'mounting. . CEILING DESCRIPTION A fixed con* calling outlet with exclusive Titus curved contour cone construction. 4 cones. Ingenious spring lock arrangement permits quick, easy removal or instaflarion of tflnar cone assembly. Inner cone assembly adjustable at factory or on job to 3 dif ferent air patterns -- vertical, horizontal, or intermediate. A fully adjustable out!at with Titus curved contour cone construction. Simply turn small cantar cona to adjust to any air pattern desired for any hearing or eooling applica tion. 3 -center cones move in unison, retain ing-same relative position for maximum uni formity of design, minimum pressure less. Inner cone assembly quickly, easily removed. A 3-cone supply outlet that combines econ omy with excellent diffusion performance. Inner cone assembly removes for fast, easy installation. Adjustable -- on the job -- to 2 air patterns by simply changing screws on inner cone assembly. Heavy-duty sponge . gasket around outer edge of diffuser assures - air-tight installations. . ' .A combination air supply and exhaust di ffuser .for heating, ventilating and -cooling. - Especially designed-for use where simplifi cation of ductwork b desirable. \6"..14" 8" 16" 10". 18" -12" 20" Primarily, for ceding applica- tionbutcan.alsobe.usedon' sidewail. ' ' '{ ' . A half round supply air. diffuser with remov- ' able * inner - cone assembly for quick, easy '* mounting.'. Adjustable --' on the job -- by simply removing inner, cone assembly and . adjusting screws to air pattern 'desired. ..Equally efficient for heating, cooting. ventv. -'taring. . , '- : 4" . 5" 6" 8" 10" 12" 14" 15" 16" 18" For exposed ductwork or flush mounting. -A square diffuser designed to deliver supply air for hearing, ventilating, cooling.in a 360* pattern, Blank-off baffles available to supply a wide variety of other air distribution patterns. Ingenious spring lock arrange ment permits quick, easy removal and in stallation of inner assembly.. . Also available but not pictured is THUS Modal TL CEIUNG DIFFUSER (supply air diffuser combined with attractive lighting fixture). Write for literature TITUS CEILING DIFFUSERS ARE: A. Furnished in beautiful mefaJescent aluminum finish. (Uniats otherwise specified) Individually packaged in sturdy damage-proof cartons. DIFFUSERS AND ACCESSORIES FOR USE WITH DIFFUSER MODEL DESCRIPTION MODEL AG-65 COMBINATION DAMPER AND GRID MODEL AG-75 RADIAL DERECTOR DAMPER TM TMS TMA T-l TL TM TMS TMA T-l TL A combination equalizing grid and damper that b quickly, easily installed in take-off. Blade opens up . directly into eir stream permitting precision air volume control. Installs flush with duct take-off. Four sets of gang-oparated blades distribute air evenly ' over diffuser or duct -- completely eliminating need ' for'equalizing grids. Unique design permits the pre cision metering of air flow to any degree desired , from full open to complete shut-off. Heavy gauge, vibration-free metal blades hold desired settings in spite of air pressure variations. Quickly, eerily ad justable from fece of diffuser. TM TMS TMA-T-I TL A butterfly damper that provides the ultimate- in simple, easy, economical control of air volume. Frie- ' tion pivots on heavy gauge metal blades keep blades et desired setring. Can be mounted" directly on dif- * fuser. Fully adjustable from face of diffuser. A circular type supply damper used to distribute supply air uniformly around circumference of Titus TR combination supply and return diffuser. Also used to control volume of supply air when balancing system -- and as a method for baffling unit to give correct eir dbtribution in irregular spaces. Individually adjust able blades have friction pivots to keem them at de sired settings. -- A butterfly type damper used on Titus TR combination supply and return diffusers. Easily and effectively con TR trols volume of return air. when balancing the system. Heavy gauge metal blades have friction pivots to maintain desired settings. MODEL CC CEIUNG CONE (Pictured with Model TMA Diffuser) TM TMS TMA T-l TL TM TR TMA TL Used to equalize the flow of air- into the neck of - diffuser or duct -- and to give directional control of air flow whenever needed. Features famous THus solid metal Airfoil louvers designed to give maximum air con- . trol with minimum noise and turbulence. Individually adjustable louvers spring-tensioned to rigidly maintain desired settings -- and provide silent, rattle-free. performance. ' An attractively stytedrscienrifically designed accessory that not.only affords maximum protection to ceiling -- but actually enhances appearance of diffuser unit used with it. Adapts Titus diffusers to flush mounting on exposed ductwork -- or flush with ceiling. y MODEL PMR PLASTER MOUNTING RING MODEL AG-75K VOLUME CONTROLLER DUCT RING SECTORIZING BAFFLES TM T-l TMA TR TL TH-. V TM TR TMA T-l - TL Specify side for baffle. An ingenious combination plaster mounting ring and duct ring that greatly reduces* cost, rime, work of flush mounting. Fastens by neck to duct and serves as plaster stop. Automatically provides correct ceiling opening and canters diffuser to it. Eliminates csitring hole in plaster. Does away with extra duct-work -- ' extra connections. Sturdy metal construction. . An opposed acting damper that serves as an air flow equalizer -- es well as a volume control. Positive shut off .when desired. Made of heavy gauge staeL Available for exposed duct, work and other applications. . Blanking baffles available for special applications. ' ^ 01 OTHER TITUS DIFFUSERS UNEAR TYPE air diffusing grilles APPLICATION Designed for continuous line use. in sidewalls, window tills, floors of banks, hospi tals, schools, other public boOdiags. Equally efficient for cooling, heating, venti lating. DESCRIPTION Extruded aluminum, 1Vk", 2", 2Vi", 3", 3W and 4" widths. Model C-ISOO lou vers in front fixed at 0a deflection. Model C-2615-- louvers in front fixed et 15* deflection. Choice of bor ders, dampers. Any width or length on special order. . .Series TMD SQUARE AND RECTANGULAR AIR DIFFUSERS Provide efficient, draftless, noiseless a i r distribution from any ceiling or sidewall location. For standard in stallations, tile ceilings, drop frame installations, surface mountings. . Square or rectangular--1, 2, 3, or 4-way patterns. Stand ard type TMD or type TMDC with interchangeable cores and choice of 4 styles of mounting frames. PERIMETER DIFFUSERS Models P-115 and P-75 New advanced design with dual adjustment -feature as sures plenty of capacity and the correct air patterns for both heating and cooling. For use in any size roominstall on inside or outside MOOEL P-125--adjustable for heating, adjustable for cool ing--simply move control. Built-in damper. Neutra-Tone finish. 24" in length. MOOEL P-75--tame as Model P-125 above except does not have heating or cooling ad justment feature. NOTE: Titus Perimeter Diffusers are packed 12 to e carton with each diffuser In dividually packaged in strong, dam age-proof cardboard sleeve. ScUe& ^epte4eMtaUve& AJcron, Ohio Albuquerque, N. AIL Atlanta, Ga. Baltimore, Md. Baton Rouge, La. Billings, Mont. Birmingham. Ala. . Boise, Idaho Boston,' Allass. ' Buffalo, N. Y. . . Charleston, W. Va. ' Charlotte, N. C. Chicago, III. ` ' Cincinnati, Ohio . Cleveland, Ohio ' - Columbus, Ohio . Dallas, Texas . Davenport, Iowa Dayton, Ohio Denver, Colo. Des Moines, Iowa Detroit, Michigan Fort Wayne, Irtd. Fort Worth, Texas Grand Rapids, Mkh. Hartford, Conn. Houston, Texas Indianapolis, Ind. Jackson, Miss. Jacksonville, Fla.. Kalamazoo, Midi. Kansas City, Mo. Little Rock, Ark. Los Angeles, Calif Memphis, Tenn. Miami, Fla.' Milwaukee, Wts. Nashville, Tenn.' Newark, N. Jersey New Orleans, la.. TITUS MANUFACTURING CORP i* Ul ^'uttccfreU (ZitteA New York, N. Y. Norfolk, Va. Okie. Gty, Okie. Omaha, Nebr. Pittsburgh, Pa. - Philadelphia, Pa. Phoenix, Ariz. Portland, Oregon Richmond, Va. Rochester, N. Y. St. Louk, Mo. St.. Paul, Minn. Salt Lake City, Utah Sen Antonio, Texas San Francisco, Calif. Seattle, Wash. Shreveport, La. Spokane, Wash. Syracuse, N. Y. Tacoma, Wash. Tampa, Fla. Toledo, Ohio Washington, D. C. Wichita, Kansas OUTSIDE OF U. St Caracas, Ven. S. A. Edmonton, Alberta, Canada Honolulu, Hawaii Montreal, , # Quebec, Canada San Juan; ' ' Puerto Rico Toronto, Ontario, Canada Vancouver, B. C.,' Canada / Havana, Cuba - WATERLOO, IOWA CATALOG No Fin-Tube RADIATION residential TRIMLINE for RESIDENTIAL HEATING sam&.-r* $. I ^ "!ff UNOVECTOR* for COMMERCIAL, INDUSTRIAL and INSTITUTIONAL HEATING, CLASSROOM f hmm. LINOVENTILATOR for HEATING-VENTILATING CLASSROOMS 0 The VULCAN Radiator Company 775 Ca pileLAve., Hartford_6^ Conn.__________________________ TYPES OF RESIDENTIAL INSTALLATIONS SPECIFICATIONS ACCESSORIES Z* ~ ^ ' TRIMLINE^I** ' "Hot WateVor"| X Available in lengths up to 1 2'. One-piece back and top. Snap-on cover finished in prime gray or zinc coating. Can be curved (at factory) for special installations, at extracost Rounded end enclosures, joining pieces and comer pieces. Full length positive position dampers. . \ AIReTRIM^l 4 L1 . ,, 4/ Available in 2, 4,6,8 ^ ^HWARM'^AlR^ and 10' lengths with TRIM , I:,. ej LINE design. Finished in prime -r Bosoboord^rrj . .. or zinc coating. Avoiloble with or with out positive position damp er. iy^^LECTRICl <TMmuI|e| . TRIMUNE enclosure design. Assembled in 3'. A', S', S', *' V> 11' ond ,3' '"xdu.. with junction box. 110, 208' and 240V, 500 to 3500 watts output. Standard TRIMUNE ac cessories available. For wall - to - wall retaliation, enclosure, without element, con be furnished to fill in. Vulcan - Service is available through more than 40 manufacturers' representative "offices and hundreds of jobbers and contractors, conveniently. located, throughout, the nation. The Vulcan Service, personel are trained heatingexperts. They are closely backed at'. " .the factory by Vulcan's top-fGght engineering staff. . - CATALOGS . . . TRIMUNE Catalog AIR-TRIM--AT 101 ELECTRIC TRIMLINE BULLETIN Design MANUALS for oil TRIMLINE products available upon, request. INDUSTRIAL VULCAN LINOVECTOR LINOVECTOR MATERIAL Tub* Fla* ELEMENTS Tube SIZE Has Stud Sled Stud Copper Copper Steel Steel Steel Copper or Aluminum Copper or Aluminum 154* IPS 116'PS 2'IPS 1*6' (!%' OOl 116' 0%' OD) .316* x 316' 414' x 416' 416' > 416' 3'/*' x 3%' 416' x 416' (Furnished in lengths up to 13 feet In Increments of 1 inch) Steel LINOVECTOR furnished threaded ot chamfered for weld1*10. Copper LINOVECTOR furnished for solder^oint fittings. ACCESSORIES SPECIFICATIONS Style X Grilles available in flexible segments for ' angular installations. Also, comer pieces, end endo . sures, sloping and ceiling type grilles. Expanded metal type. 'Vi* diamond mesh (No. 16-18 gage steel). Black or ivory Finish. Any lengths up to 8'. End enclosures, "RexiComer" (inside or outside). Rush Joints, Dampers, Ac cess Panels and Enclosures for inverted mounting. 18-, 16- or 14- gage zinccoated, rust-resistant, bonderized steel, or prime coat. Lengths up to 8'. slopingtoplS "ENCLOSURE ' STYLE 'CS fc STYLE CSw||j DELUXE CSM Full line available. Flush joints, "Flexi- Corners", Dampers and End Enclosures. * ' ' 18-, 16- or 14-gage zinccoated, rust-resistant, bonderized steel or prime coated. Furnished in lengths up to maximum of 8' in one piece/One unit front and top. "Rexi-Comers'VEnd En closures, and Joining Pieces (2Vr wide for outside joining). ' Solid front. 18-, 16- or 14gage zinc-coated, rust-resistant, bonderized steel or prime coat finish. Lengths up to 8 feet. Full line of matching ac cessories, including all flush joints, rounded end enclos ures and knob-operated dampers. Available with top and front louvre outlets-br-either. 18-, 16* or 14-gage zinc-coated, - rustresistant, bonderized steel or prime coated. Lengths up to 8'. SILL-TRIM ^ /ENCLOSURES?^ - Full line of matching accessories, including rounded end enclosures and knob-operated damp ers. ' Sturdy baseboard design. Full One of elements available. 18-,. 16- and 14-gage zinc-coated, rvst-resistant, bonderized steel or prime coated. Full bade optional. Rugged cover support brackets. 'INSTITUTIONAL V: BASEBOARD^** JOINTS -- efl wdMwn shown above, except Style X sod Style F, sraihbh with "H" (eiat (ee screws or belts seeded). LOUVRES -- "Mist" (smell slxs) louvres available eatyls 10- end lb-gage steel, in 1* Increments. ' Standard louvres, available In IB-,. 16- end. M^tst eieel > 3' lacrements. '' HEIGHT -- ell endoseres available In I-, 2- and 3-row Ugh, except Institutional baseboard (ealy leew Ugh). BAKED ENAMEL -- aQ endoseres, sxcept Style X, available in I standard baked enamel colors (at extra cost). See Vntcan Color Guide. LINOVECTOR CATALOG MSB available showing fall line of VULCAN elements,, accessories end enclosures. Including com plete ratings. IT t! * 'ZPE^C UNOVENTILATOR* HAMMOND,, A Quality Schoolroom Heating-Ventilating System At Lowest Cost To Fit Almost Any Budget! LEADER IN BRONZE r HAMMOND i i HEAVY-DUTY VALVES 600 SERIES GATE VALVES No. 609 GATt. 25 lb. WSP With .olid wedge disc. Complies with Federal Spec. No. WW-V-54, type 1, A. May be repacked when fully open. Recommended for heavy-duty services up to 125 lb. w.a.p. and 200 lb. w.o.g. Available ji' to 3'. Also avail able with drainable end. Specify on order. ' Construction features identi cal to No. 609. but with sweat end connections for use with copper tubing. Meets Federal Spec. No. WW-V-M, type 1. class A. Available X* to 3*. Rising stem, solid wedge disc gate valve. Rated 125 lb. W.S.P. Meets MIL Spec. WW-V-64, Type 2, Class A. No. 618 features double disc, meets WW-V-54, Type 3, Class A. Sizes to S'. Both styles available in copper-to-copper as No. 617c and 618c. No. 622 BRAZING TYPE N.R.S. GATE, ISO lb. WSP No. 629 & No. 631 UNION BONNET GATE, ISO lb. WSP With solid wedge disc. Meets Federal Spec. WW-V-54, type 1. class B. Large sixed, generously proportioned, with extra strength for serv ice requirements at 150 lb. -w.s.p. 300 lb. water, oil or gas. Available K' to 3'. With construction features and ratings similar to No. 619, but with socket ends for brazing. Used for industrial construction and general pip ing where resistance to shock is of primary * importance. Available Jf' to 3'. No. 615 available for 12S lb. w.s.p. With double wedge disc. Stur dily designed for services to 150 tb. steam, 300 lb. w.o.g. Available X* to 2'. Rising stem, solid wedge dw gate valve. Meets MIL Spec. WW-V54, Type 2, Class B. No. 631 features double disc, meets spec. WW-V-54, Type 3, Class B. Sizes X* to 2*. Both available in eopper- to-copper as No. 629c and 631c. No. 611 MONEL STEM GATE, 100 lb. WSP Non-rising mooel stem solid wedge disc gate valve. Meets military specifications MILV-11B9, type A. Rated for 100 lb. wxp. 200 lb. w.o.g. Available X' to 2*. No. 612C & No. 612 N. R. S. GATE, 2001b. WSP Heavy-duty, non-rising stem gate valve with solid wedge disc. Rated for 200 lb. wap. Also available as Fig. 612 with monel trim to meet government specifi cations MIL-V-20231A (Ships). Available X* to 3'. ROUGKIMG-tN DIMENSIONS OF SEXES 600 GATE VALVES N*. 609 lh.411 N*. 619 Ms. *21 Ms. 424 Ns. 429 4 Alt Ms. 612C Ms. 410 aze A a c A S C A CABC A ft Ift 3ft 1ft Ift 3'ft 2ft 1ft 3`ft 2ft ft 1ft 3ft ift 2ft 3ft ft mw Sft 2ft I'ft 3ft Sft ft I'ft 3ft 2ft 2ft 3ft 2ft 2ft 4ft 2'ft 2ft 4ft 2`ft 2ft ft 2ft 4ft 2ft 2*ft 4ft 2ft 2ft s 2'ft 2ft 3 7ft 2ft CA I'ft Sft 2ft Sft Aft 2ft 7ft B CA CA 3ft 2ft 1ft S'ft Sft Sft ?ft I'ft 3ft Sft Sft 2ft 2ft 4ft 2`ft Aft 2ft Sft 5 2>ft Sft BC 2k S'ft 3K 7ft 1 2ft 3ft 2ft 3ft 3ft 2ft 2ft s'ft S'ft 2ft 3'ft skt 2ft 7'ft a'k. 2ft 2ft Sft S'ft 3`ft 3'ft 4ft 9ft 1ft S'ft 3ft 3 3ft 3ft 3 2ft 4'ft Sft 2ft >ft sk Sft 9ft Sft Sft 9ft 3 2ft A*ft Sft S'ft 4ft 9ft Ift 2ft Aft 2*ft 3ft ft 3`ft Sft 7ft Sft Sft 7H 3ft 3ft lift 4ft Sft 0ft 3ft 3ft 7k Jk 3`kt 4ft 9ft 2 3ft 7ft 3`ft 4ft 7ft 3*ft 4ft 7ft 4ft 4ft 7ft 4k 3k 12ft i 5H 12ft 3ft ft 7ft 4K A lift 2ft iU. 9ft ft 3 9ft 4ft 4ft 9ft 4ft 4ft 9ft 4ft 'ft 15ft 4ft 4ft 10 4ft 3 ift. ift ift ll'ft Sft K `JL Sft I7`K m Hft 5ft .... No. 610 QUICK OPENING GATE, 125 lb. WSP Solid wedge discis operated with quick opening lever. Meets military spec. MILV-12126 (CE), class 1. Rated for 125 lb. steam and 200 lb. non-shock on water, oil or gas lines Available in X\ H\ 1*. IX\ IX' and 2* sizes. - . 5 ) l t : i Ji BHAMMOND ^ HEAVY-DUTY VALVES 400 SERIES GLOBE VALVES Sturdily constructed. All sixes have swivel discs--J(' size and largerhaverenewablediscs. Meets - all service requirements up to 125 lb. working steam pressure, 200 lb. water, oQ or gas. Available X'to2'. Extra strong brass disc globe valve with union bonnet. Meets Federal Spec. WW-V- 5IA, type 1, class A. Ratings and sizes same as No. 410. No. 411 & 4HC REGRINDING GLOBE, 200 lb. WSP With plug type brass disc, union bonnet. For dose control, throttling, regulating. Meets mil itary spec. MIL-V-1202-A. type A. Stems ofmonel. Has gland follower. size and larger have renewable and swivel discs. Sizes to 2r. Available as No. 41lC with high tensile bronze stem instead of monel. No. 413 COMPOSITION DISC GLOBE, 150 lb. WSP No. 414 MONEL DISC GLOBE, 200.1b. WSP Construction features miwIt to No. 411 but more heavily constructed for all types of service up to 300 lb. steam, 600 lb. water, oil or gas. Monel stem and disc. Meets mil itary spec. MIL-V-1187, typo A. Sizes X' to 2'. Alto available with Afgft tensile bronze stem and disc instead of monel as No. 412C. Has slip-on type disc holder for quick disc replacement, stuffing box. gland follower, onion bonnet. Complies with Federal Spec. Ww-V-51a, type 1, class B. For industrial steam-service up to 150 lb. steam, 300 lb. w.o.g. Sizes X' to 2'. Also available in aopper-to-capper as No. 423. With double union ends, meets" Bureau of Ships spec. B-164, alt. 7. Has monel seat ring, union bonnet. Double union ends used for silver brazing. Primarily for ship board use. Rated 200 lb. steam, 400 w.o.g. Available X' to X'- Also available in angle type. No. 460, X* tut only. XOUGMMQ-tN DIMENSIONS SSCES 400 GLOBE VALVES Ns. 410 Ms. 411 A 411C H.4t2A4t2C Ns. 413 Ns. 414 Ns. 41* Ns. 434 Ns. 43* CA 2ft Ift CAB CA cA CAB CA cAa c k ft 2ft 1ft I'ft 3ft Ift I'ft 4ft 2H 1 ft 2VC 4ft Sft 12ft- 4ft 2ft S'ft Sft 2ft 4*ft 2ft 2ft 4`ft Sft Sft 4'ft Sft Sft 4*ft Sft 2ft 4'ft 2ft Sft 4ft ?ft Ift 7ft I'ft 4`ft S'ft I'ft Sft "7ft 3ft 3ft Sft 7`ft Sft Sft Sft 7ft sft Sft 5ft 2ft 7ft Sft 2ft 2`ft Sft 2`ft >ft 6 Sft Sft 3`ft 3'ft 7ft 4ft Sft Sft Aft Sft Vft 3ft A'ft Sft riftIft S'ft S'ft sk Sft S'ft 3 Sft 4ft 7'ft 4ft 4ft sk 4w Sft Aft Tift 4k 4k 7ft 3 3'ft 'ft A<k vW 4ft 7'ft 4ft Aft 4k 4k ft 4ft 4k 4k |Aft 4k, 1 Sft 2*. m. }i S 3k 6. 4* 4^ A set No. 415 NEEDLE VALVE, 200 lb. WSP Produced- to Federal Specification, meets requirements of 200 lb. working steam pressure. Available in X'. X'. X', X'. X' No. 435C "500 BRINELL" GLOBE VALVE PLUG TYPE With "500 Brinell" hardened stainless steel disc and renew able seat. Rated 300 lb. steam, 600 lb. w.o.g. Available X' 1 ST. No. 433 and 434, 150 lb.. 200 lb., de signs of No. 435C. No. 435. "AAR" globe, meets MIL-V1187B, type 2. g HAMMOND INDUSTRIAL VALVE COMPARATIVE FIGURE NUMBER REFERENCE CHART n ^DESCRIPTIONS 107 450 18 1 166/'Rad?atC!'Angle JAN-V- ?iTyp^M 47G - -- - 125. /Glob,:Renewable 404' Stead:Competition _ __ _ . . _ 125 6*, / Giob, rott:Dt*c 410 r51 1 58 2140 234,WW-V AVfypVI, Class _ 411 70 160 407 750 270-C Glob# -- _ 650 110 412-C 413 414 415 431 433 .434 SOp/'GloborRegrinding 50ft f'Gtobc.':BcnwablCoraDbSiiocE>n.'^ 5 1 7^w>/.y- iA;:Typ ,'ddxsBj ^HHI 200/.-Giobe,''Regrtnding DoixblelUnioriMR^ 8iBsnhipi^Dwg. -t 200 4 4; |;GW '>i* dlo 200/ Globe/Convectof^Xv-^ \1 jOf'Gjobc/'Pbg-TyiM^'-J^IIIMI IZOO/jGlobtfAig.Typt^T.-l ijSHIII 3672-E Globe .205 95 154_ W.S. 68 120 4270 -- U14P 212P 245P 409 1130 123 106-A __ _ 906 743-G -- -- 546P 73PS 556P 370 120 520 150 _._ 238 180 --- 5-58 -- 1708 SOO/GtobepAAR Plug Typo * 435 1 1678 376 256 700'MN. V-I ,'Typo ' P P 1890P _- P_ 435 300 382 260 576 670 1710-C r /;Gteb^PVi5' P P UPS P 123 33; /,'Angle; Brow DbeJ,'.j'v jfisigNR 453 2 59 2141 235 651^WW-Y-SIA/Type B^Oom _ ISO/'Angle," Bendwobl~ GaeipoMriwm)pAAj 454 -51 7 96 214 108 521 151WW-V ArTypo^OoM' 300r /-Angto,Rogfinding 455 167 -8 364-6 306 557 1132 371 122-C -MittV-f ,'Typa V'<>7- 200.' /;Anglo/ Regrinding 458 202 8 70 161 408 752 271 112-C AAJI-V-f A^Type. ", 600 25 440 95?t /:Ga^C)bgbtd'DtK'RninV Stoai^^^E 125' /'Gate;.Sdiid:Disc -609 54 3 3 438 4 2129 370 99 507'NRSifVCW-V- , Typoi; ao c M^H 125 7 /lGdto,rQvick Opeldg 610 2 26 432 9 302 106 362rMu.w;i i j(caa 200; /-Gote,''Sbd Disc, MRS 612 -20231 2230 2 24 380-C 'Mii-Y A(Sbip) .aon'Urr^a^^M Anglo Angle 458 - i ~~ ^ __ _ -A 70 -- ? 125? /-Gcto,Sotld'Di^^HRSV'^ME|HB 613 1320 1240 1822<$eftler&><tiWW.V-^Typ.l^aSiSBM 615 2 5 5 8 4 5 1273|l S/ G t^S ^ Dbc:iNRS^ rwDeiriifeM 125 /IGotd?SolidiDbc^RWrtg StemB^^S 617 54 428 2 2127 47 97 500X^!BcS^W,W-V- ^TvpewoaHH 5125/,GdtefDobl*'De.feting'Stej^^Bi 618 54 7 430 3 2125 62 100 500uJnionJJorinef.WWj_V- ,'Jypo tO^ratq^H -- W. - . _ -- -U -U -- 619 622 626 629 631 901' 902 904 906 909 A 50fGoto/Sofid:Doc; NRV^SSjHB^B 54 39IW,W*V- ;doSB; TypW i^H 50 5ff / Goto; o<;d Dt*<",NRS, Brtninsj^^H 50 8 1^^^3l_ / Gdte,'SoGd Disc, Union. bnr 54 .8\WW-V- . fyoo.D. Cldu 1 50 06 0T /.~Go*d' uble bc. Rbmg StoglpBlBA 1 Unjdn'Jonftot^Mil-W.W-V-Sd.'Typoiffl^S^SB TM/jdbids, im ` * , 'M| 25 ^7 1il /vd V*f icaJi- ^ -5y/rCb*dE. SWmg .WW-.V lAJ^SMM ;:Typ'JV,.CIajs A 25si / Ot-ek. Swiny.'tfotiny 17547;Mli:V^ - (Havy):typ'orA,{ao^gi^B 50 4-\ /Swtno^Cho<t.Co<apdtit>on;Pa jMR WW^V-SiA/Jypiry.CkittB 437 - 431 431 --20 24 34 ,_ 34 14 4 W.S. 12 11 ! 12 73 75 406 _ ! 4)2 2153 1 670 98 -- 1273 -- 2150 64 96 2151 49-U 750 _ 2142 64-U - 7152 i 237 418 119 -- 2144 92 134 _ _ 1272 _ - 352 - 512 5-14 514 514 658 -- 578 _ 596 95 - - -- 97 _ _ 150 011 8-16 . 045 134 409 8-37 029 _ _ 427 8-66 033 89 1A 8-22 U-01 _ _ . ._ -- - 8-64 041 -- ----- -- 138P 40-9P ! I 8-29 8-62 0525 0501P 5445 _ 8-78 _ 544P 427P 8-74 0545 151 033 8-216 046 90 3A 8-222 U-03 _ 429 8-266 035 135 411 8-237 031 -114-- -- B ' - 27 66 ` 8-115 0250 _ ; _ 8-116 _ 37 i _ _ 1 8-138 _ 427SJ. 427BA 90 ; _ 0280 -- i - 0250F4. 25 86Y 8-105 0252 . _ 86X 8-106 0253 23 103 8-130 0224 23 LS. 45 -- 103A -- 0224FJ. 8-121 0228 ' _ 784 8-120 U-0226 133 705 : 8-121 8-316 0228 0607 490 -- - -- 103. i 198 8-319 0600 0601__ ; _ _ ' __ FJ. - | 205 nr - M HAMMONDflmMOJf BRONZE VALVES JiAAfMOJVD ESMtA&tS IS^OBJES HAMMOND. INDIANA - . PACKAGED BOILER FEED UNITS PAGES 2-3-4-$ 2-STAGE POWER PLANT PUMPS PAGES 6-7 VERTICAL CONDENSATE UNITS PAGE 8 61 -- UNDERGROUND CONDENSATE UNITS PAGE < ENGINEERS' GUIDE TO d) C u LKi - J] PACKAGED BOILER FEED & CONDENSATE RETURN UNITS FOR INDUSTRIAL & COM MERCIAL INSTALLATIONS COMPLETE WITH SELECTION DATA & SPECIFICATIONS ROTH turbine boiler feed pumping units are a line of factory assembled systems for boilers from 40 to 500 HP operating at pressures up to 200 PSI. Fac tory assembly reduces costly erection labor on the job site arid insures factory responsibility for the proper selection and function of the entire unit. ROTH boiler feed units consist of one or more motor driven pumps combined with a hot water storage tank or receiver and an automatic make-up valve to replace system losses. These units are used with most fire tube and scotch marine boilers when operated for process steam at pressures above 20 PSI. They are also used in modified form with water tube boilers. The motor driven pump operates intermittently and is controlled by a special float switch or pump con troller mounted on the. boiler water column, start ing the pump at low water level and stopping it at high water level. Water pumped from the vented receiver is usually at least 70% hot condensate and varies from 180F up to boiling point, depending on the amount of flash steam returned. Boiler feed pumps with low suction head tend to lose capacity as water temperature approaches 212F. By lowering the suction head to zero and raising the water temperature to 212F it is pos sible to vapor lock any turbine or centrifugal pump. For this reason the buyer should be protected against hot water fall-off by performance guaran tees in which suction head and temperatures are clearly stated as in the selection table (see page 4). All pump models furnished with ROTH Boiler Feed Units are thoroughly charted for performance in handling water close to boiling point and are rated for their capacity at 206F. In addition to certified hot water performance, ROTH engineering has resulted in many other de sign improvements assuring long, dependable opera tion. By eliminating ball bearing end-play, impeller position is permanently maintained. The new ROTH pumps have heavier shafts than any pre viously manufactured equipment and are covered by a written guarantee (see page 12). . . Other components of ROTH Boiler Feed Unite are manufactured with equal care. Welded steel receiv ers are of 3/16 inch copper-bearing steel and in ternally coated with a rust-resistant phenolic resin O 1953 -- Her E. ftotb Company 2 SEE PAGE TWELVE lining. Large diameter piping between receiver and pump eliminates pressure drop and includes a large strainer especially made for use on these units. Me chanical make-up valve for receivers up to 100 gal lon capacity is float operated. A solenoid valve controlled by a float switch is supplied for units with ISO, 250, 350, and 500 gallon receivers. Available at additional cost are the following items: (1) Separable tank cradles instead of welded legs available on all sizes. (2) Dished head receivers made to 75 lb. ASME specifications, with or without code stamp can be substituted for 3/16 inch steel flat head receivers. (3) Perforated tube heaters with manual or automatic temperature-controlled steam valves. (4) Magnetic starters, alarm bells, pressure gauges, and signal lights. (5) Motorized valve in place of solenoid valve. ROTH TWO-STAGE TURBINE POWER PLANT PUMPS delivering up to 200 PSI at 1750 RPM are standard on this line of equipment. Largo passages between stages, special suction entrance modification, and the inherent va por handling characteristics of the ROTH turbine impeller contribute to this pump's ability to efficiently handle hot water at high pressure differential and low suction head. SPECIFICATION FORM Famish and install as called for on the drawings one Roth Model ................ (specify simplex or du plex) boiler feed unit suitable for --......GPM at a discharge pres sure of................ PSI. Trie unit shall consist of the following components: (1) One (substitute two for du plex) Roth Model............stand ard fitted power plant pump -certified by the manufacturer for a minimum of................GPM of 206"F water at______ PSI with 4 ft suction head. The pump shall be guaranteed by the manu facturer for one year against defects in workmanship and ma terial and shall be guaranteed for ten years by the manufacturer ' against shaft breakage when flex ible coupled to a motor of recom mended rating. The pump shall contain an internal system for relief of pressure on the packing to insure maximum parting life. (2) One non-code welded steel receiver made of 3/16" thick cop per-bearing steel with phenolic resin limngt integral supports, and connection for inlet, outlet, drain, vent, make-up valve, ther mometer, and gauge glass. (Sub stitute if desired one dished head receiver built to ASME code for unfired pressure vessels rated 76 lb. working pressure with or without ASME inspection stamp but with separable cradle sup ports and connections for inlet, outlet, vent, drain, thermometer, gauge glass and make-up valve also with Hand hole or manhole for cleanout per ASME code de pending on tlw* diameter of the receiver.) (3) One fresh water make-up. valve consisting of a % inch sole noid valve (specify 1 inch on 500 gallon receivers) controlled by a ' float switch mounted on the re ceiver for_______ phase ............. volt current, (substitute float operated mechanical valve with pressure reducing valve set for ' 15 PSI for units with 60 and 100 gallon receivers). ' (4) Piping between the receiver ami pump to consist of one (sub-' stitute two for duplex) vertical section containing a gate valve and one (substitute two for du plex) horizontal section con nected by Roth L-Type strainer to insure minimum pressure drop between receiver and pump. (5) One (substitute two for du plex) 1750 RPM drip proof mo tor for --...... phase .--........ volt current. Motor shall not be loaded in excess of NEMA serv ice factor for integral drip proof motors. Make shall be General Electric, Louis Allis, Howell or equal. (6) One (substitute two for du plex) magnetic starter of ap proved type suitable for the above motor, with holding coil for--------- volts. (7) Gauge glass of proper (8) Tank thermometer. (9) When provision for heat ing water in the receiver is required add, "One brass perfo rated tube heater installed in the receiver." When automatic tem perature regulated heater is re quired specify, "One brass perfo rated tube heater installed in the receiver connected to one tem. perature controlled regulating valve mounted on the heater connection." TURBINE PUMP DIVISION ROCK ISLAND. ILLINOIS Boiler Feed Unffs wifh 1750 RPM Power Plant Pomps TWO-STAGE^ POWER PI PUMPS" ^ SERIES 3000 - Ji.2rvS!*!5O*"M?*OrUe0shsiSewtwioi^-Io* i >"^7> r^^rS-snu*****a.c . f^SSSS.'SS.ssw './rji^sr-SL ,,,, ^v^nitwowNi i coicct waaj^-JS^Sf^ t-'> '-&rOtO* **sW*Ba *sst <r"'";--.=....~^ ,--sss' - V>J-'$ ***** , Hstorfr. ~pgM irJ [213.215,-' *0,2560 E|i?Ss 51-1/2 [3*37? jl7-ll/as] -?F-4 [1S6-4ll//1166M^mIS T5m [VsTIs [6-5/Tslml g, ivg KeS^teS foSSE: ilroto fc-ii/ysUslrifrl SS-T/Uj|52-U/Isb-I3/lSi [ ' Tl-3/16 '-r CoTM^^rddfip-pfoof raoiort.'. Co*ar,totally enehw.d motor*. ~ m 3-1/IS -i V- Jjjwki . Sac Bit-"' lf*i <. 3521-37*1 m PA !u-u/n 2% ? 3751-375] BA ft* 12-7/8 4 TVl , -23756-37* a PA 12-7/8 4 fe ^ *. V if- .r^ ^ a&; SERIES 3000 and 2000 ROTH.Two-Stage Power Pumps serve a variety of appli- - cations found in bawi power service such as feeding water to steam boilers in a range of 100 to 500 PSI as well as condensate return, autoclave, desuperbeater, and vacuum condenser service. Series 3000 and 2000 have excellent hot water handling characteristics due to the targe passages between stages, the special suction entrance modifications, and the inherent vapor handling characteristics of the exclusive ROTH tur bine impeller design. Both series are ruggedly built with extra heavy duty, flexible coupled shafts guaranteed for 10 years against breakage (see ROTH Guarantee, page 12). End-play has been completely eliminated and pressure lubricated ball bearings maintain precision performance and assure long life under hardest usage. Steam engineers understand the proper use and main tenance of packing fax better than the harder-to-replace mechanical seal. To cater to this preference, ROTH Power Plant Pumps are HgwigrwH to handle hot water at high pressures with ordinary packing. Pressure on the packing has been reduced by approximately 65% through the installation of a throttle bushing between the impeller and stuffing box in each side. Packing maintenance is tnimmitwi nnfl adjustment mad* simple and easy. SERIES 3000 two-stage turbine power plant pumps con sist of ten models divided into two general frame sizes. ' Balanced dasign is one of the several factors resulting in the better performance and long life of ROTH series 3000. In -these pumps, the two stages are arranged so that loads (continued on next page) SELECTION TABLE--SERIES 3000 -- 1750 RPM ~ - .r t ~ i -- *-- M 1 uTfetfaiEL kna Ttt Bert la Feel tothaplaolgal:----------------- * MAI It*. 3521-3741 3751-3781 3756-37* C*K 2Vi' Section 2* Oisdarze 4* Suction 2V6* DiscfcVH Cat 4* Sactloa ttrtrBtttfe Tost Pn**. -- PSI 500 600 500 600 500 600 Mb. Voter, Oil or (-M --PSI 400 500 175 325 5001^ 225 400 *SE PAGE TWELVE _ between the two stages. This is achieved __ Ka AAint nt s4iw*har0A nf tha hsn find typnffttng discharge of first stage with suction of second glage by an external channel. Pmops are standard fitted, bronze fitted, and all bronze god are supplied with ASA flanged connections. Models 3621, 3711, 3721, and 3741 have the by-pass betWL-rn stages located under the pump. Two impellers are arranged in series. Models 3751, 3756, 3771, 3776, 3791. and 3798 have the bv-pas9 between stages located at top of pump. Models Jlui numbers ending in digit (1) contain impdlera ar- raQged in series. Models with numbers ending in digit ^6) contain impellers arranged in parallel. SEB1ES 2000 two-stage turbine power plant pumps congjst of fifteen models divided into two general frame sues. Standard fitted, bronze fitted, and all bronze pumps are supplied with ASA screwed connections. TWO-STAGE POWER PLANT PUMPS .to"TrT su IV* SZ1 iv* - 2531 IV* S31A IV* 2541 m 2551 IV* 2561 IV* out*. IV* IV* IV* IV* IV* IV* IV* SI ill y y 3' 3' TsW Hoi ia Ftt Itt 156 206 2SB 156 (04 4SB 506 BOS 12 .1.6 :o.s 9-1 14 7 4 14 5.4 42 17 65 55 4.6 3.6 L2 6 7 7.6 65 5A 4.6 3.6 btLP LI L3 1.5 1.7 2.0 22 15 17 yu 3 7 12.4 M i V.0 4/) HI) 1.7 13 24 12 1.7 63 5.4 HP 1.1 U L5 L8 2.0 13 25 18 20 SPM 12.1 16 66 65 7 3 61 4,9 13./ 7J 11 4.9 tSHF 1.4 Lb 1.8 2.1 14 17 31 3.4 4-9 . 19.1 16 < 150 13.7 lib 10.0 15 70 25 18 68 71 5,6 11.1 45 7,4 b4 51 BHP 1.5 13 2.1 2.5 18 L2 26 4.1 4.5 25 GPU 114 ii.3 117 107 9.7 12 tz 24 86 74 SPM 14? 114 12.5 11.6 10.6 96 IS 74 BHP L9 22 2.5 r2.8 3.1 3.5 28 42 -17 146 12 91 7.2 20 6PM a 57 16 118 LL4 10 65 GPM ?n A.? 16 138 11.4 9.0 65 BHP 1.7 2.0 2.4 U 3.4 4.5 50 6PM 17.7 BHP U ?1 6 17,6 16 14,5 17 8 ,L3 14./ 13 7 11.7 17.1 lb.6 15.7 14 114 10 9 z 2.6 ija 3.5 41 4.5 5.0 CPU 34 X 23 75 71 17.7 13 5 9.7 10 2571 IV* IV* 2581 IV* IV* 2591 IV* IV* 2631 2V* 2651 2V* 2671 2V* 2V* 2ES1 2V* 7? 71 14 6 15,7 11.8 7.7 BHP U K 33 3.8 4.4 5.1 28 16 GPU 763 *46 73.1 71 6 7Q0 18 6 17-2 2L2 196 186 6PU 17/ 16.9 16 7 114 ISO 126 15.1 BHP 2.1 Zi 3.2 U 4.3 4.9 25 fh 71 6 17.0 1? 7 6.5 4.7 215 245 70 14 K 9.5 4.7 71 f 20.8 70 7 117 14.8 15 4? BHP 3.1 3.1 KB 4.5 5.4 67 7.0 7J 4. a :i5 31 27 2J 19 15 *> 78 71 3' 3? 77 7.1 70 16 BHP 3.2 3.1 4J 12 11 71 12 9.4 47 44 4( 35 31 GPM 41 44 4C X 3? 77 6PM 31 3! 34 37 76 BHP 3.6 4.< 5.2 6.2 12 14 6PM 69 6! M 6PB S BHP 4.! 5. 55 41 51 44 A 41 7J L< 41 34 X 71 9.1 11.1 GPb 54. SU 415 461 411 GPU 4 4 4 36 1 mi 741 BHP 5.1 5. ii 6.4 73 11 6PM a 7' 71 65 51 GW 6 V 4< GPb a X 2 BHP 5J 63 13 10.4 1L6 MECHANICAL DATA--SERIES 2000 Mate! to. Hrtrartittt Tact Fno. -- PSI e.i. Bn. 211-2591 2631-2691 cm IV**. Suction IV** Dlscbarre Cm . 2V*" Settles 2* Dischsrre 500 600 500 600 Ita. wt. Oil or 6as -- PSI CJ. Bn. 400 500 400 500 12 400 12 400 ___PMSSUtt PACKtHS'ON Ht&H'.' ' PUSSUXE KMP. PtESSUtE AT tOTH- STwate aottsts % of: . .. DOCHAJtSC PRESSUKE. -PACK : ... UGHTU fO# to P.i'L'WHW - .. > pump soEva.oPiNe.2co p.s:l^''j ` INSTALLATION DIMENSIONS^ SEKIES^OM^ ii Miter Fr. N6MA St4* -A, i r,-iy; C 0 y. r.f C ftir -.s 182; 1M' 34-5/16 36-1/8 -12-3/4 X 61V 3-21/32 ft213,215 ^ 38-S/lS 39-7/8 14-9/16 40 6* 4^21/32 ft2S40.-2S6U 41-1/2. ,42-3/4 15-9/16 40 6* (-21/32 -*r- --* Mater fr. NCMA St* - * > f? C 7 ~ F`- 6: ft181184' 36-5/8" 38-7/16 13-13/16 40 5V* .-5 - ft;.-S 213.215' <0-5/8 42-3/16 14-9/16 40 516 S . ft25417^25611 429/16 (8-13/16 15-9/16 40 6% 2-23/32 284U;285U 18-11/16 (9-13/16 16-11/16 46i TV* 3-7/8 IV* kt Covar* ttendard drip-proof moiou A* Covar* totally aaelotad motor* i` `"I". M * P-` i, 28V* 2. 4V4 35-9/16 M/16* 38V* 3-1/11 5V* 42-9/16 2-9/16 38V* b-i/w 6V4 42-9/lS 2-9/16 .* -- -- ' r --' - - P KJ. M: -P 38V* 3-1/16 4V* 42-9/16 2-9/161 38V* 3-1/16 5V* 42-9/16 2-9/16 3SV* 3-1/16 SV* 4443/16 443/16 43V* 3-7/16 49-5/16 3-5/16'. V&kfc's \7?~' " 'i ' U yi _* i Sat Dia tiao na. 2511-2591 w 8-3/32 1-13/16 ,4 m IV* 2631-2631 5ft 8-13/32 M/4 W. 2V* 2- ROT H. ROTH COMPANY JURfl|NE PUMPDIVISION ROCK'ISLAND,' ILLINOIji` VERTICAL CONDENSATE ;,f.UNITS (witb^east iron or .. `welded^afeel ^receivers) SPECIFICATION FORM Furnish and install as shown on the drawings one vertical condensate unit, Roth Model ...... -.......or equal for....... .......... sq. ft EDR at................PSI. Pump shall be 1750 RPM ver tical submerged type with cor rosion resistant liners and stainless steel shaft Motor shall be General Electric or equal 1750 RPM, all angU drip proof construction, mounted above the high water level for.... .....volt (specify ac tual operating voltage) ......... cycle -- phase current Float switch shall be 2-pole Square D or equal, direct ac tuated by all-copper float and float rod with visibly adjustable float rod collars mid suitable for across the - line starts on single phase current up to 1 HP Load. A magnetic starter shall be provided suitable for the motor supplied. (Specify for 3 phase current only.) The receiver shall be of high quality close grain cast iron with 2 inch inlet 7 inches above floor level (specify .9-7/16 inches for 23 gal tec.) and provided with vent, overflow, and drain connections. ' DESCRIPTION ROTH Vertical Condensate Units are ragged, dependable, long-lived equipment engineered to include the most desir able features needed in pumps for local condensate collec tion or small steam heating systems. J?6* .uTM^s are especially useful where condensate must be drained from low return piping. (Floor to inlet Higfai^ on 10 and 15 gallon receivers is 7 inches.) A minimum Qf floor space is required due to location of motor mi switch on top of receiver which also permits shallow pit installa tion without hazard of flooding the electrical parts. All models listed in the selection data below operate at 1750 RPM providing a full range of pressures up to 60 PSI for radiation up to 20,000 sq. ft EDR. This low operating speed plus special bronze bearing for unusually long, trouble-free service. Up to 20 PSI working pressure, the pump operates on cen trifugal phase. It will not vapor bind at 210*F. All working parts are of bronze or stainless steel, A fully guaranteed General Electric or equal drip-proof, all-angle motor with thrust load carried on ball hoaring^ is standard equipment The unit is controlled by a heavy Square D, 2-pole float switch adequate for acroes-the-line starts on single phase current up tol HP lnd All cast iron receivers are equipped with 2 inch inW plus drain, overflow, and vent connections. SIMPLEX UNITS are float switch operated provided with cast iron receivers of 10, 15, or 23 gallon capacity. DUPLEX UNITS are standard with two float switches, one connected to each pump separately. Floats are set at separate levels to start second pump at peak returns. They are furnished with cast iron receivers of 15 or 23 gallon capacity. (Mechanical alternator can be substituted for the two float switches at slight additional cost.) Units also available with heavy gauge welded steel re ceivers made from copper-bearing steel having .20% cop per content and lined with phenolic resin. SELECTION DATA -- VERTICAL UNITS --1750 RPM SS-FL Paaf Buchan* Presan -- PSI IS 15 26 39 46 M 61 Kcceim Bata liepliei Baplet 2JX0 Mil No. IDF 10F inf IDF PM 17V UH I TV I7VI 1/4 i/4 1/4 i/4 1/3 1/3 1/2 la. HL - 7*- r Jait No. 10F I0F inf I7f 1PM 17V LTV 1750 17V LTV WV ITS ni 1/4 i/4 1/4 i/3 1/3 1/2 1/2 In. Ht W r 7" 4.000 Jolt No inf I0F 10F T7F 40F 1PM 17V 17V l/V 17V 17V Oia. 1/4 1/4 1/4 i/3 1/2 1/2 1/2 lo.Kt. V r 6.000 Jait No. I3F 17F I7F 19F F F 17V 1750 Tfl 17V 17V On 1/4 1/3 1/2 3/4 3/4 1 1a.m. is* 7- r iomo Halt No. 15F 1RF Ifif 41F PM I7S0 1 TV 17V TV 1750 1/4 \n 1/3 1/2 3/4 Jail No. nF TV nr 4RF PM 17V l/M 17V TV :tv 1/3 1/2 1/2 3/4 1 .1 2244* In. HL 7' to. HL 7' r r UoitNa vr 57F 54F zu 1PM 17V 17V 17V 750 i/2 V2 3/4 1 1 iW n-HL TZVt"x22VT 9-7/16* 9-7/lfi* Unit No. Sfif WF 5ftf PM 1750 17V 1/V 1/2 3/4 3/4 1 ,rt la. ML 9-7/16* 9-7/16* 1. All pomp capocltiei i i delivered ft tomperatora up to 200*F. 2. Will not vapor bind at 2I0*F. 3. CootsIt factory for talactioa* involving snetotad motor* or nrtteba*. 4. Salact tfca salt according to datlgn putters and maximum axpactad tqsara faat of direct radiation on tija location. 5. Spadfy timplat or dsptax. k Spacify entrant and voltaga. A (pacific operating voltage sbosld be tpnclflad rather than dual voHego to ettisl in the propat talaction and . iottelUtion of tbn aqslpmnnt. ROCK ISLAND, ILLINOIS 8 SEE PAGE TWELVE description ROTH Underground Condensate Units are indicated where condensate must be drained from underground piping. The floor-to-inlet distance is 12 inches to make possible a pipe done for draining purposes. Low silhouette design permits gush floor installation, locating under storage tanks, etc. Motor, motor mounts, and pump are essentially the same as ii?*^ on the vertical condensate unit shown on proceeding All underground condensate units operate at 1750 RPM -rovMing a full range of pressures up to 60 PSI for radi ation up to 20,000 sq. ft EDR. This unusually low oper ating speed plus special bronze bearing makes for unusu ally long, trouble-free service. The 1750 RPM pump operates on centrifugal phase up to 20 PSI working pressure. It will not vapor bind at 210#F. All working parts'are of bronze or stainless steel. The im peller is precision-located between the adjacent faces in a fixed to prevent it "riding" the lower face. Motor is a fully guaranteed. General Electric or equal drip- * proof all-angle model with thrust load carried on ball rings and controlled by a beavy'Square D, 2-pole float switch adequate for acroas-the-line starts on single phase current up to 1 HP load. All receivers are of heavy cast iron or welded steel construc tion flanged at top for bolt-down cover and equipped with 3 inch inlet plus vent connection. Interior is coated with a rust resistant, phenolic lining. Receivers are- for atmos pheric vented service only. ` SIMPLEX UNITS are float switch operated with switches ` set to start at high level and stop at low level. DUPLEX UNITS are standard with two float switches, one connected to each pump separately. Floats are set at separate levels to start second pump at peak returns. (One mechanical alternator can be substituted for the two float switches at slight additional cost) SELECTION DATA--UNDERGROUND UNITS--175C RPM Bait No. Cl Bte'r. SB. Rce'r. Sr. Ft E.D.R. Pea* Bis. 6PM Pres. ttatar Pop HP Sin Rtlll-210 RU11-215 RU11-220 RUI1-230 RU10-240 RU63-2V RU63-SQ RU11-310 RU11-315 RUU-320 RU13-330 RU22-34Q RU63-3S0 RU63-360 RUU-410 RU1*415 RU1242D RU13430 RU63440 RU63450 RU45-460 RU12-610 RU19615 RU19-62D RU2I-630 RU43440 8U43650 RU4M60 RUL6-U0 RU1M1S RUU-820 RU70-830 RU44-M0 RU50-6S0 RU23-1010 RU25-1015 RU25-1Q2D RU46-1030 RUS0-1040 SU11-21D SUU-215 SUI1-Z20 SUU-230 SU10-240 SUS3-2S0 SU63-2S0 sun-aio SU11-315 SU11-320 SU13-330 SU22-340 SU63-350 SU63-360 ' SU11410 SU12415 SU12420 SU1J430 SU63440 SU634V SU45460 SU12-610 SU19-615 SU1962D SU21-630 SU43-640 SU43-6S0 SU49660 SU16-S10 SU1B-815 SU1S-620 SU70-630 SU44440 SUS0-SV SUZ3-1010 SU25-1015 SU25-102D SU4S-1030 S1BO-1040 2/300 3,000 4,000 6/00 L000 10/00 10 1$ 20 30 40 V V 10 15 20 V 40 V V 10 15 20 X 40 V V 10 15 a V 40 V V 10 15 a V 40 V 10 15 a X 40 3.0 1/4 3.0 1/4 33) 1/4 3.0 1/4 3.0 1/3 33) 1/2 33) 1/2 4i 1/4 45 1/4 4.5 1/4 i 1/3 45 1/3 45 1/7 45 1/2 63) 1/4 6.0. -1/4 63) 1/4 6.0 1/3 6.0 1/2 63) 1/2 6.0 1 9.0 -1/4 9.0 1/3 933 1/3 93) 1/2 93) V4 9.0 3/4 9.0 1 123) 1/4 1231 1/3 123) .1/3 123) 1/2 1233 3/4 1233 1 1533 1/3 1533 V2 153) 1/2 1533 Y 1533 1" 1* 1* l* 1* 146* m* 1* 1* 1* 1*' w* 144* 1* 1* 1* 1* 144* 116* m* i* i* i* l* 144* 1V6*. 1* 1* 146* 146* 146* r r 146* 146* RUS2-1S10 SU52-1510 10 225 1/2 144* TRU52-1515 SU52-1515 15 225 1/2 146* RU54-1S20 SIB4-1S2D 153)00 a 225 146* RU60-1530 SU60-1S30 X 225 146* RU56-2010 SU56-2010 RlBMJlS SU56-2015 20/300 X 15 303) 3031 1/2 3/4 146* 146* WS5WMD SU5WD2D a xa V4 146* Receiver Bata Step). Dept C. Oia. Depth Inlet la. Dpt 8X 16* XT30* 30* rr 12* 1Z* Cap. Dia. Depth Inlet In. Dpt 8V 16* 30* 30* 30* rr 12* ir Cap. Dia. Depth Inlet la. Opt 8a 16* X' 30* 30* rr 12* 12* Cap. Dia. Depth Inlet In. Dpt 8 90 16* XT 30* 30* rr 12* 12* Cap. Dia. Depth Inlet In. Dpt 40 20* 30* r 12* Cap. Dia. Depth Inlet la. Dpt <0 20* 30* , 3' - 12* Cap. Dia. Depth Inlet la. Dpt 40 20* 30* r 12* Cap. Ota. Depth talat In. Opt 40 ar 30* r 12" V 30* 30* r 12* X 30" 30* r 12* 90 30" 30* r ir 90 30* 30* r lr Furnish and install as shown on the drawings one under ground condensate unit, Roth Model ...... ............. or equal for ............sq. ft. EDR at................. PSI. Pump shall be 1750 RPM ver tical submerged type with cor rosion resistant liners and stainless steel shaft mounted inside the receiver. Motor shall be General Electric or equal 1750 RPM, all angle, drip proof construction, mounted above the high water level for_____ volt (specify ac- Float switch shall be 2-pole Square D or equal, direct ac tuated by all copper float and float rod with visibly adjustable float rod collars suitable for across-the-line starts on single phase current up to 1 HP load. A magnetic starter shall be provided suitable for the motor supplied. (Specify for 3 phase current only.) The receiver shall be of high quality close grain cast iron (or 3/16" welded steel with phen olic resin lining) with 3 inch inlet 12 inches below floor level. DESCRIPTION These units axe essentially collection stations for condensed steam in heating or process systems. The packageunit consists of a receiver tank and a motor driven primp controlled by a Boat switch mounted in the receiver. - Successful pumping of water at temperatures in the 190F to 200*F range from low leg receivers re quires special pumps designed for those tempera tures. - High temperature returns are often caused by de fective traps or local dumping of process steam - cause ordinary pumps to vapor bind. ROTH pro tects you from such occurrences by thoroughly test ing and rating for hot water performance the pump models selected and guaranteeing them to perform as rated in the table. If desired, pump selection will be certified for 200*F temperature if request accompanies order. Such certification is based upon special test data obtained from hot water tests run upon the pump of your selection. (A flight charge is made to cover cost of test) ' Since many of these units will be located at points distant from the boiler room, maximum attention has been given to providing pumps that will give dependable service without constant maintenance. For this reason, these units are equipped with ROTH End Mounted Single Stage Pumps operating at (continued next page) SPECIFICATION FORM Furnish and install as called for on the drawings one Roth model -.............. simplex (or duplex) hori zontal condensate unit or equal for............ GPM at ............... PSI at 200F to consist of the following: One (substitute two for duplex) Roth 1750 RPM single stage end mounted pump with mechanical seal and sealed ball bearings certified for ................ GPM at ............... PSI at 200"F. Pump shall con tain stainless steel shaft and bronze impeller and be guaranteed for 10 years against shaft breakage when driven by motor supplied. - One welded non-code vented receiver made from high quality copper-bearing steel sheets and' internally lined with phenolic resin lining. (Substitute 75 lb. ASME code receiver with or without stamp on cradle legs if desired.) One (substitute two for duplex) General Electric, Louis Allis, Howell or equal 1750 RPM drip proof motor selected within recommended service factors - for intermittent service and guaranteed by the manu facturer at the point of selection. Current charac teristics shall be _______ phase .................. volts. vm ? '-.DIMENSIONAL DATA--SIMPLEX & DUPLEX UNITS ~ UttfT NO. - r /' f UBE6.UBSa, UBUWJBm ,`v - ^'UBa6. UBlB-UB123.-UCL07-UCl22.-:U5HJE55..U98. * = - - =, ..^.wm-ucia; UE6WE96,DE99-UE10l,-..S ' J .'V _T2tlfW-UF90. UW4IFI00, un05, U6101 -r-. . 1 - ; '.2 ' -i Ufe-97. UFS2, UFUJ2.1/FJ06.-UF1O7. U6102-UG1IJ5 .,r.r-= >V2ft` -ASA'tUnea. _ One (substitute two for duplex) Square D two pole float switch or equal suitable for direct connecting to single phase motors up to 1 HP and for pilot service on larger single phase and all three phase motors. (Substitute mechanical alternator for two float switches if desired on duplex units.) For units with three phase motors or large single phase motors one (or two) magnetic starter is re quired.) One (substitute two for duplex) magnetic starter of approved type suitable for the above motor, with holding coil for ....____ _ volts.- The entire unit to be factory assembled and factory guaranteed .' DIMENSIONAL DATA--SIMPLEX & OUPLEX UNITS' * Tick r, Sin A si. 0v. C 0 Ef6 Sins. DO. N J K l .0 a B$ VZ ft-i 20 m. ft 35 Cal. 36 39 26H 18W 23ft 22 24ft 38ft 16ft lift 4ft 16 5ft 19 3ft 2ft 3ft 15 1ft 2 44 46Vi 2Wt 19 26ft 22 24ft 36ft 18ft lift 4ft 18 6ft 26ft 3ft 6ft 6th 15 1ft 2ft rift-? 60 cal- bO 62 36W 24^6 32ft 22 32ft 91ft 24ft 16ft 6ft 22ft 7ft 23 6 7ft 9 19ft 1ft 3 -, 166 at- GO 61 41V4 27 37ft 23 36ft 63 25ft 9 27 10ft 28 s 8ft 9 20ft 1ft 4 1ft an cai. /!> 76 46 2SW 41ft 30 39ft 56ft 27ft 19 10ft 32 12ft 48 5 16 9 20ft 1ft 4 1ft `* -4:v ^ *. v--:'" m gpy E.^ROTH CQMPANY TUBBINE PUMP DIvfsioB [ROCK ISLAND, ILLINOIS 1750 RPM and furnished with sealed factoryhibricated bearings and dependable mechanical to eliminate the need of periodic lubri cation and re-packing. (Grease fittings are Provided to coat the bearing with a waterLgistant pereervative once or twice a.year.) Packed pumps available if specified. Because of the steep performance curve char acteristic of ROTH turbine pumps, these units will a fairly constant capacity over a considerable range of discharge pressures -- a distinct advantage over comparable centriugal-type pumps. At operating pressures lower than design pres sure the pump will not slug the boiler in heat ing systems- Also there is no increase in motor load at under-design-pressure conditions. - SELECTION DATA -- HORIZONTAL CONDENSATE UNITS --1750 RPM St Ft BtiPr E.DA BP Us. rv HW CPU BscMrerSttl tits -- Sinslcx 1 aI tit to U a a a M n 75 Csp. Dis. L*tk Pi* VL L*th BL Sin RL U00 7ft 259 ft ft ft ft ftDoit No. Pfc|. IJB110 U8U0 UB110 UBUO UB1U UB115 UB88 Motor H? ft ft 20 1$ Z 2 23ft lft 27ft X 26ft ft ft2.000 15 500 3 Udit NO. Pl. UB110 U81U U8110 UBUO UBUO U8116 UB8S Motor KP ft ft ft .ft ft a 16 a 2 23ft lft 27ft X 26ft ft3.000 22ft 750 4.5 Unit No. fkg Uotar KP U8110 UB110 UBUO UB1H U8U2 UB88 ft ft ft ft ft UB8S ft a 16 zs 2 ZTft lft 27ft 36 28ft 4,000 30 1M> 6 Unit No. Pk(. Motor No U8110 iTBlll ft ft (Bill uaiu ft ft UB88 ft UB88 ft 176118 1 UBUO 1 a ft z .2 23ft lft 27ft X isft 6JOO 45 1.500 9 Unit No. Pkc. Motor KP USUI UB113 UBU4 UB70 ft ft ft ft UB71 ft U671 ft UB11S UBI20 11 a 16 a 2 23ft lft 27ft X 26ft 8JOO- 60 2.000 12 Unit No. m. UB113 JB113 UB70 Motor Hp ft ft ft UB69 ft UB7I ft UB97 1 1B121 US122 1 lft a 16 a 2 23ft lft 27ft X 26ft 10,000 75 IM 15 Unit No. Pk<. Motor.HP U8117 U8U7 1B117 ft ft ft 11869 ft UB97 1 UBU9 JBU2 lft lft 7B123 2 a 16 a 2 23ft lft 27ft X 26ft ft15,000 112ft 3,750 224 Unit No. Pk(. Motor HF UCU8 UC108 1JC109 UCUO UCUO UC1Z2 ft ft 1 1 lft JCU2 JC123 23 X 18 32 2 25ft 2 28ft 43ft 28ft ft ft27,000 15(7 5.000 30 Unit No. Pkc. Motor HP UC107 UC120 LIC12) ft UCUS lft UCU5 lft UC124 2 JC125 3 17C125 3 X 18 32 2 25V -2 28ft 13ft 28ft 25mo 187ft 6,250 374 Unit Ha. ng. Motor HP vesT 1751 i '1 (IE55 UE95 lft lft UE96 2 UE96 2- UES7 3 UE97 a 22ft X 3 32ft 2ft 38ft 50 36ft sum 225 i*sn 45 Unit No. Ptf. Motor KP UE7L UE71 UE71 UE9S UE96 UE96 UE37 L1E1D0 60 22ft 36 1ft 1ft lft lft 3 32ft 2ft 36ft a 36ft 3SAO0 262ft 8,750 52.5 Unit No. Ptg. Motor KP vies UE69 UE95 UE95 UE96 UE79 UE85 UE10 lft lft lft lft 2 7ft so 22ft X 3 32ft 2ft 36ft 50 36ft UX0 300 10POO 60 Unit No. Pkj. Motor HP um ift UE69 lft UE95 lft UE79 3 urn 3 (JESS UE85 UE101 7ft a 22ft X 3 3Zft 2ft 36ft SO 36ft SOM 375 12J0C 75 Unit No. pk|. Motor HP UF84 1ft UF64 lft UF94 UF90 3 UF8S 5 UF91 UF105 UF10 S 7ft 10 100 27 40 4 37 3 40 56 40ft RIO) <S7ft IA250 174 Unit No. Pkf. Motor HP unoo UF100 UFUD UF101 UF102 UF102 UF106 UF10 222 5 5 7ft 10 100 27 49 4 37 3 40 56 40ft p;Check .#hesey:FoofuresT!pJ^^^.| tveV:ncf.' mounted construction insures^comp/efel. seporo- ^chanical ? end.^.~. yTrR*enewable -iiners^prop^^^^m i&^Ytded in aflsmode/s^pl^' ^\^$ecf)onicol}seai'.cb n"6c '^Cfe^ocetAw/fhouf disturb- ^^'ihgxpipipgpr^motor~ - ^` :rrc.>/5^^2 Czz 'C Faptaiy^fvbricated sealed i> earirigs%fiminate'^ieed. - - Mk.- : forTperiodic.lub/jcatibri^. f^^^andPprofec^^Qgainst^ddh^r^ pr*1 ger. of. overgreos/ngr-^:^ ^--.T tr ' ~ I |'vV';Heovy stainless steel iAaff_.-s. v fVi- and large, bearings pre- . - tx^venti-couplmg vibrations \'2i-^f^rn'beingfronsmiffed.to'^ is' fzy .impeller^ '* ~' MOM 750 snx 150 Unit No. Plf. Motor HP U6102 UG1Q2 US102 U610E UG105 IICIIK 38105 5 5 s 7ft 10 10 10 :200 a a 4 41V 44ft 74 4Sft A PARTIAL LIST of ROTH BOILER FEED fond CONDENSATE RETURN ONIT USERS?' Tlii Inf of ROTH customers inJiutM tk* nation-wide acceptance of ROTH Boiler Feed end Condensate Return Units, end Power Plant .. !'DEFENSE INSTALLATIONS' Tv ^ Pumps. Should you cere to contact users in your area, please write r-,, M|or units installed in.well over 100 air force bases, army posts. *V'1j for lot of names. . -A and -proving grounds, amaonesi naval stations, and.'radar-stations ' V ~ on the. North -American'continent.-.-. ` -A"'-.'-* ' - ROTH GUARANTEES AGAINST SHAFT BREAKAGE! The , J shaft is the keystone to good pumi|p design. A rigid shaft . properly supported by well protected bell bearings will prolong pump life by many years. All Roth pumps ere eouipped with unusually heavy shafts or pro tected by balanced loads or both. Becausa of superior pump dasign, cases of shaft failure are extremely rare. . To emphasize this important quality the Roy E. Roth Company now . often this unprecedented guarantee: ^ fuuttee HOSPITAL INSTALLATIONS * New Mexico State Hospital ' i.-A'.-' : Las Yagas. New MexKo'- - ^Chanty.Hospital 71-.5. * .Naw OrteansrioulsiaM.'- -* P.H.S. Indian Hopitelk'*.*'' -_V- Tahlequah, Oklahoma' . Frtorva Hospital - Fnona.-Texas :St. Margarets Hospital. ~ FredcMua..Kansas. ti'-'Y-- s - -^Huntsville Hotpital -iT'l~-xp'rC -.St. Mary * Hospital . _ --*.',:Huntsvdle. Alabama- --?-.-wv.-a6alesburg.-Illinois.-,-- - \ r-f McPhersoa Coenty Hospital'% : A'It McPherson. Kansaii-n.- -Sedgwick County Hospital : -i '.Wicbrta.Kansas. tMerey Hospital . SSitatu Hospital Oklahoma Cily. Oklahoma ^v^2-' *v. -MUIedgevilla.- Georgia 3. s'^-Mtd-Wand Hospital Sav --.Wausau Memorial Hespifat -r\-. . -'..j7,':.-.Bethpage; LH., NewYorfc-^S j" "* --4*Wausau..Wisconsin - .. Vt TVfv* -T- - . '..V --*1 A -^INDUSTRIAL INSTALLATIONS ** ^ ^ All Rotli pumps sold after September I, 1957 will be ' guaranteed by the company against shah breakage for tan years from the data of shipment when flexible coupled to electric motors of sizes recommended by the factory . . . The company's liability under this guarantee will be limited to repair at the factory of any pump with a broken shaft when such breakage' occurs within the specified period. Shipping cost to and from the factory to be borne by the owner. . CERTIFIED HOT WATER PERFORMANCE The Roy E. Roth Company will certify the hot weter performance of ny model recommended in the foregoing tables upon receipt of request for certification with tha purchase order. A slight charge will be made to cover the cost of a special hot water test. TWO OTHER ROTH TURBINE-PUMPS AVAIL ABLE FOR SPECIALIZED APPLICATIONS IP ROTH TURBINE CHEMICAL RUMPS--are a special adaptation of - tha tgrbina principle specifically de signed for continuous, high pressure service under adverse conditions of t American Bridge Division J. Pittsburgh; Penn*.r .-&.Ford Motor Co?-, "-^Xrar^vvtyNorthvilte. Michigaa ;;:^.;^!' If Atlantic Refining CoT^' T 'o*' - T --* -------- -------- ; -Wichita, Kansas' ^p^iThe Bordan Co. $<?- - ..-Goodyear-Tlre E Rubber.Co. -'^igj?iv?55;-'>-Des Moines. Jowa -;-?l '^,'V -j .- - /T -1 Lbs Angeles;Califi.u. .r-< - Akron. Ohio-:' - Rock.Island..III. <Si-.vf-;(j Port Newark. New Jersey y* *l,tt.!vile. Tenn.^- ."W. fSSfcV-.GrieeWicbtelephone Idg;'*^-'" CiacinoatBt. N. r. v' ^. **_ = er.V0wich, Coanw:tiCut\;^'-: -*r''i -'.'r Leominster. Massacfausi Carnation Co Oakland.Md. .^3,--'-3.Cameron. W.'Va:>eS`fe^j'j: _ Wyoming.'Nr-.cTs~- -. *Hr ug-hes A. ir.c.r.aft ,,- vt. , IT Sudiv.u, W(it> r- , aetieviii*.ohm" H*w1horn* Calf jk-fei- .--Glasgow.-Ky.tr.- ^-^-.vr^ i^L lH2SrirS;<M*`:1',ermaoo,`"-Was*hSS; vts-_wrtj*>'fejm.' .. r Watertown: Tenn^'* fv%.RuAv(ltaroh.oiP^->d-a^g,4, . Uocoin Assembly Plaht.-.-.-Hc^ r?- Oiv. of Ford Motor Co. . i.,...Chevroletv ASi - Novi. Mic(ugn^ f' *-*V '. vf-.i * Flint Mich Otterbura.' Mi.(cSh6..:-.._i.. \New Mexico State Penitentiary^. -v* Sant. Fe. NeW Mexko.^ T -Chicago. BurtingtOB,^9^1 ^*5i-5f.:Joseph? Mo. N `X.' Intamaffon'al Airport^^ ' > I--Alliance, Nebri ;i`-;iArouorokrae, id,.Mo> ;>.... '4S4S&W York/Telephone Co^' R'^'GrtybiilT/'WyocBing'J^ .fcA- ,, . licago, Milweakie^St, Paurf^i^^^fe'-N^Ywk- Nt.-Y^'^ Jiicagol Miheeakie^St, Paul PacificRT-RCo'S;.; *.... J. --a - Tacoma.'Waihinglon MKfeMad^oe^^S-0'^V^fi*i '*. . . Chicago111InoUS^i-i-ifei,'a^' Peoples Shopping Center.^- S^Sroux'Fails, 5.-0ci- LiucoIn Park/Mlchlga.*'^-- --mt. USAGE: Hot end cold water, acids, caostic rotation,' liqeiEed gases, solvents, aad by- corrosion or temperature. These pumps have a record of continuous service equalling and often surpassing that of other, more costly typos of high pressure chemical pumps and are recommended for clear liquids to 100 t^fiCuHis^WrtaM.Cdrp: ......... fc^-^^North Hollywood,Cant.-1ay-.ya 5%-vLEa'gle Food: . Milan'Itni 1 *- J` ' ^Shopping Center. : ^j5f. Paul. p<^i'VieKmondTsfitefl JIislala.hn-d^.2S* UiilH io stores la ^L,FtVu;FedCfeoCuVfnHeateC.leivrkPt.onWwhleeragdigaSn:hNt.t/CYao.'trtp^.o-^.^>.^-^^JnG:^cre..e>ea4W>^as, o>"t;aLiviiilrI-oioB<:W^SoeHawi arPr--bi,eNc..^. -rei,|e* of 41 Nates. iJltvS*. ^ -r]Wiinifu' YTucoaui"^ "" T ity, 1*140; temperature, --S0*F to +t00*F; HP, % to 30; . NPSH, at low as 3 ft; cp viscosity. . USAGti.-Ammonia, Ireont, RANGE: Head. ISO to ILOO ft.; differential, SO-TOO Kl; capac ity. I to tOO GPM; temperatare, -00`S to -t-300*F; HP. S-40 BHP; NPSH, I, 2. or 3 ft. ROTH TURBINE LOW NPSH PUMPS -- are designed to meet suc tion-loss problems in liquids heving low suction heeds with viscosities to 100 cp and temperatures to 300F. This ability derives from their ex tremely low NPSH characteristic which is due to the low disturbance at the -suction and a gradual pressure build up. throughout the pumping cycle. Available in single or 2-stage design with exclusive booster stage. -SCHOOL.INSTALLATIONS , vT 4 ??tA.'4.M.-CollegevTrS^:J*N-Ti>i'- - CowviMe Central Scboof>.s.`'V f > -. .%kas Craces. New Mexicot-i/i^.- . JLowvilla, New.York.-^f^?Y- >f-: Chaplain KapauniMa^ai^^g^^^MaVberry^Scli^vvgj-Sf;^.*^ ^bMighSttoelV ^ Wkfita;Kansas^V^ y.*--.T'T Wichita: Kansas, . - \ . tecflntiin St:Elfibn"t? t.. JjK f^or-k-Harlfor'd. New York" --f W^OalavaivOarieo Hlgh S^hool-'^-Ti;^55^Roe'l*ll? T,T5,!',P High School. ColbradoV^j f-fe'^^Df^aB^SWalmUi^KeaMnvsasiihT: --^/iii: ^ "'t- ochene. lll ools ' V .......... " `Jr.'HighS-Vc'h--EEfoa.ors^tj^SLSvi>f;t-l-a-tVoS'ii,inSiSSwcahtairoltlmeworala'Cs,t-eKeran;ut*Nra.aesi>-wS.Tchoorko.rBldgS. a--ljl<na4.H4Sigh School >' ^ ' ->' * tnTef^c^fCiairf^;. fc`.i i w i,ii.u " t L"C?,GSra5nSite?Cciif.y,`.'lIllIiInJohhr^i - '-PS-- **.--**. t.'d ^eVlAt'Biiid Hiflt. - Tr-- r*s;Jji'*i.iAYallay Center.High School. --- Center, Kansas. P .".Indiana Univertlfyrv' r-'a-' 5-.vBloomingtoa. ladiaea.-- it^v^Wbitworlh College .-",o. -5.V-JgiS. -Spokane.-.Washington^r. .~s^?<fisr - -a ROT E. ROTH COMPANY TURBINE PUMP DIVISION RcTcK ISLAND UUNois^r'' ' ' ilyg ~J' _____ - 1 " - . MANUFACTURERS' CATALOG DATA PAGES 63-- 476 J H On pages 63-476 will be found the Catalog Data of 309 man ufacturers whose products are described and illustrated. For the convenience of the user of THE GUIDE 1959 there are ten main divisions: Air Conditioning....................................... ........................................ 63~148 Air Conditioning and Heating Piping ...................................... 149-1S4 Air System Equipment............................ ....................................... 155-0269 Controls and Instruments...................... ............... ......................270-O295 Expansion Joints....................................... ......................................296-0 303 Fittings and Flanges................................ ........................................304-O30? Floats............................................................. ......................................308 Heating Systems......................................... ......................................309-# 427 Insulation.................................................... ......................................9423-0 439 Publications and Exposition................. ...................................... #460t 469 On pages 7- 24, under each of the index headings--Air Clean ing Equipment, Fans, Humidifiers, Ventilators, etc., will be found a list of manufacturers ofany desired products, fully cross-indexed, and the page numbers in the Catalog Data Section where the prod ' ucts are described. By reference to these indices, the manufacturers' names and the page numbers, any item of equipment or materials, and the pro ducer's address, may be located quickly. Ajr Conditioning oir*i Srctem* 63 AIR & REFRIGERATION CORP. 4.39 Madison Ave., New York-22-N.Y. 271 Milton Ave., S.E., Atlanta, Ga. Sales Representatives in Principal Cities Foreign Representative--Rocke International Corp. 13 East 40th St., New York-16-N. Y. EQUIPMENT ENCLOSURE--INSULATION IN ONE PREFAB PACKAGE ARTICULATED UNITS Units with unlimited capacities are furnished for standard, double duct or multizone distribution systems. Designed for each particular application, they incorporate coordinated equipment to fit within the space available. All units are factory test-assembled to assure fit of parts prior to shipment. We call them ARTICULATED UNITS. COMPONENTS A typical system often combines air mixing, filtration,-wash ing, cooling and heating, humidifying or dehumidifying and air circulating equipment. More complete systems may also include the refrigeration compressor, water chiller, evapora tive condenser, pumps and boiler with all being enclosed in a factory insulated casing. Blow-through multizone systems also require outlet air dampers for mixing hot and cold air streams for each zone. HOUSINGS Unit housings are assembled using AAR factory insulated panels. Available in indoor or outdoor weatherproofed con struction, the panels consist of an interior galvanized steel sheet to which is applied the insulation, aluminum vapor seal and outer protective sheet of tempered hardboard. For outdoor use an additional weatherproof skin of aluminum is added. To save additional cost, the machine room floor may be used as the bottom of each enclosure or an insulated drip pan may be included. ADVANTAGES Articulated units are custom engineered to suit the per formance requirements and space limitations of each particular application. All parts are selected to work in co-ordination with the rest of the system. Office time and effort by the purchaser are reduced in adopt ing articulated unit construction. One purchase order covers materials and services normally requiring a number of separate contracts. The factory insulated housings do away with the usual mess of field insulation and plastering. This may be an important factor, particularly, in older buildings such as department stores, etc., where valuable stocks of merchandise cannot be removed. Prime coated before leaving the factory, the exterior presents a continuity and neatness of appearance which needs no field painting unless scratched or marred in handling and erection. The panel type construction permits sections of units to be dismounted quickly and easily where it is necessary to remove bulky internal parts for repair or replacement. CATALOGS For further information on A A R Articulated Units or Factory Insulated Panels, write direct to main office in New York, or contact factory representative in your area. 1 n !M f fji s \  64 Air Conditioning INDUSTRIES, INC. 600 N. Mechanic St. Jackson, Mich. Sfc COMPLETE AIR CONDITIONING AND REFRIGERATION SYSTEMS ADVANCED DESIGN COMPONENTS Look to Acme for all types of air condition ing systems. Acme supplies a complete line of air conditioning and process cooling equipment including packaged liquid chil lers; and remote room conditioners, air handlers and multi-zone units for use in direct expansion or chilled water systems. Acme water saving equipment includes evaporative condensers, indoor-outdoor cooling towers and outdoor cooling towers. In addition, Acme offers a complete range, of self-contained air conditioners. Acme components for built-up systems have long been recognized for excellent quality. All major manufacturers of air conditioning and refrigeration equipment have used Acme components for many years. Call your Acme sales engineer for details on how he can help you with your air conditioning or process cooling problems. MANUFACTURERS OF QUALITY AIR CONDITIONING AND REFRIGERATION EQUIPMENT SINCE 1919 65 INDUSTRIES, INC 600 N. Mechanic St. Jackson, Mich. FOR COORDINATED BUILT-UP SYSTEMS . . . USE THESE 'rf&KS/ MATCHED COMPONENTS DIRECT EXPANSION COOLERS I to 300 tons SHELL AND TUBE CONDENSERS IH to 700 tons SHELL AND COIL CONDENSERS * to 10 tons HEAT EXCHANGERS 3 to ISO loos LIQUID RECEIVERS 3 to ISO tons OIL SEPARATORS S to 100 horsepower AIR COOLED CONDENSERS 3 to 100 tons o DIRECT EXPANSION COILS WATER AND STEAM COILS A complete range .of sizes and capacities for almost every OEM, built-up system and replacement need. Flow Pac Packaged Chillers-- 1% through 5 hp V Flow Cold Packaged Wafer Chillers--3 through 30 tons Flow Cold Coding Towers-- 3 through 20 tons Model HE Flow Therm ' Packaged Water Chillers-- 20 through 60 tons Model DE Flow Them? Packaged Wafer Chillers -- 20 through 125 tons Flow Mizer Cooling Towers-- 20 through 175 tons How Mizer Cvaporof/Ve Condensers-- Capacities to 200 tons Air handlers--4 types m 40 models from 665 to 19,200 cfm Seif contained packaged air conditioners--5 models from 3 to 15 tons, air or water, cooled Remote room conditioners--. 4 types in 16 models from 200-600 cfm Multi-zone air conditioners--5 models from 4,060 to 19,200 cfm Self contained packaged air conditioners--24 models from 20 to 60 tom, air or water cooled  66 Air Conditioning AMERicAN-<$tandard AMERICAN BLOWER DIVISION Detroit 32, Michigan AMERICAN-STANDARD PRODUCTS (CANADA) LTD., Toronto. Ontario CANADIAN SIROCCO PRODUCTS Branch Offices in Principal Cities AIR CONDITIONING--HUMIDIFYING--DEHUMIDIFYING--VENTILATING-- HEATING--VAPOR-ABSORPTION--DRYING--AIR WASHING AND PURIFICA TION-EXHAUSTING EQUIPMENT AND MECHANICAL DRAFT APPARATUS American-Standard, American Blower Division 67 Diaflo Conditioners--fan-coil type air-conditioning units for cooling and heating multi-room buildings with chilled or hot water. Fan draws fresh and re circulated air across coil, cooling or heating or de humidifying it. Write for Bulletin 9887. Tonrac--single-stage hermetic centrifugal refrigerat ing machine. Maintains constant chilled-water tem perature from 0 percent to 100 percent load. No cycling is required. Completely automatic load control-- pneumatic or electronic. Induction motor suitable for any type of starting equipment with network and pri mary voltage. Bearings arranged for positive thrust and forced-feed lubrication. Single-level construction simplifies installation and maintenance. Request Bul letin I486. Capillary Air Washers--for high efficiency in clean ing, humidification, cooling and dehumidification of air.- Air is forced at low resistance through long, ir regular passages of small size formed by a large amount of thoroughly wetted glass surface. Write for Bulletin 41SS. Inductor Units--small room air conditioners for cool ing and heating multi-room buildings. Preconditioned primary air, supplied under pressure, induces a flow of room air through a coil in the unit, then into the pri mary air stream. Mixed air is discharged through top of unit. Write for Bulletin 8887. Air Conditioning Units--four basic types. Eleven sizes. Capacities from 800 to 40,000 cfm, and for oper ation up to 9 in. static pressure. Type A for unitarytype applications: Summer cooling and dehumidifying, using chilled water, direct-expanded refrigerant, or brines; winter heating, using steam or hot water. Type S is the same basic unit as Type A, plus spray system, water recirculating pump and eliminators; combines the washing, air cleaning, humidifying, and evapora tive cooling with the cooling and heating of the basic unit conditioner. Type AB Multi-Zone Unit for either horizontal or vertical air flow. Plenum and diffusion device provides even air distribution over coils. Type C combines the features of the capillary air washer with the basic Type A unit. Request Bulletin 9887. Heating and Cooling Coils--American Blower heat ing and cooling coils offer a number of improvements in design and construction. Available in a complete range of sizes and types, including: Bulletin B-1818 Type S steam coils Type D double tube coils Type U return bend coils Type B booster coils Bulletin 1581 Type W water coils , Type C clcanable water coils Type X direct-expansion coils ' ` Bulletin B-1818 Type H heavy-duty coils Bulletin B-1418 Type D-i double tube coils Sirocco High-Pressure Fans--especially adaptable to high-pressure air-conditioning systems. The mul tiple forward-curved blade design gives it a relatively high static pressure characteristic, so for a given duty it runs at about half the speed of backward-inclined blade fans. Data on request. Packaged Air Conditioners--completely self-con tained units that cool, filter, dehumidify, circulate air; heat, when equipped with heating coils. Hermetically sealed motor-compressor assemblies. Six sizes; 3 ton to 20 ton capacities. Exceptionally quiet. Request Bul letin 6185. Also air-cooled models, Bulletin 8085.  68 American-Standard, American Blower Division Heattag cat American-Standard^ American Blower Division 69 Venturafin Horizontal Unit Heaters--available with one- or two-row standard steam and water coils, or serpentine hot-water coils (results in greater heating capacities at lower water volumes). These propeUerfan-type units heat quickly, quietly. Have adjustabledirection louvers. Request Bulletin 5017. Heating, Ventilating and Multi-zone Units--with air filters and Aileron Control. For use where attractive, quiet, and economical heating and ventilating units are required. Wall, floor, or ceiling mounting. Units offer great flexibility of design and arrangement to meet specific needs. Request Bulletin 8997. Venturafin Vertical Unit Heaters--can be mounted in minimum space at ceiling above craneways; has, as standard equipment, Equitemp Air Diffuser for main taining desired even temperature. Capacities: 42,000 to 560,000 Btu at 2 lb steam pressure and 60 deg enter ing air. Standard steam and hot-water coils. Request Bulletin 9017. Industrial Heaters--feature quiet, low-speed centrif ugal fans--V-belt driven to provide easy speed adjust ments. Universal cowls adjust to direct air and heat where required. Four arrangements: wall, horizontal, inverted, and floor (shown). Request Bulletin 7797. HS Fans--used for ventilating, air conditioning, and in commercial and industrial applications such as: drying, heating, fume removal, and processing systems. They are available in both single- and double-inlet designs and may be specified for clockwise or counter clockwise rotation in any of eight standard discharges. Single-inlet fans are built in seven standard arrange ments, double-inlet fans in two arrangements. Write for Bulletin A SOS. Utility Sets---complete packaged units, directly con-, nected or with V-belt overhung drive, for duct appli cations. Belt driven units available with Sirocco for ward curved blade wheels or HS backwardly inclined blade wheels having nonoverloading power character istics. Sizes for a wide variety of ventilating problems. Quiet, compact. Complete technical information in Bulletins 8314, 8414* Cabinet Heaters--for offices, lobbies, showrooms, cor ridors--any application where appearance is impor tant. Heavy-gauge steel cabinet houses high capacity steam or hot-water heating element and two or more centrifugal fans. Flexibility of mounting and inletdischarge locations make numerous applications pos sible. Write for Bulletin 9617. Gas Fired Heaters--self-contained units for clean, automatic, instantaneous heating. Adjustable louvers assure efficient heat distribution throughout the work area. A. G. A. approved. Write for Bulletin 8517. Sirocco Mulliblade Fans--operate at lower rotative and peripheral speeds for a given duty. They operate quietly at low speeds, and deliver more air per revolu tion. (Double-inlet model shown.) Request Bulletin A-801. Power Roof Ventilators--weatherproof ventilators with V-belt drive and access door in fan housing. Model HRV exhaust ventilators (shown) are hood type, and have automatic shutters and 4-way dis charge. Model VRV exhaust ventilators are upblast type and expel air high above roof, minimizing roof deterioration and preventing re-entry of air into sup ply ventilators. Model SSV supply ventilators, hood type, have motor-operated dampers and perimeter in take. Write for Bulletin 3904. ' 70 . Central Srateaut Air l^OnaitlOmng * Hamidifeetim and CooQof American Moistening Company ATLANTA, GA. Cleveland, N. C. PROVIDENCE, FJ. TORONTO, ONT. TEXTILE and INDUSTRIAL HUMIDIFICATION AIR CONDITIONING SYSTEMS The American Moistening Company has been design ing and manufacturing humidifying equipment for the textile industry since 1888. During this time, Amco has developed and introduced new equipment and con trol devices to solve atmospheric problems created by motorization, high speeds, new fibers, new ma chines, new techniques, and operation in varied cli mates. . . Four basic advantages are to be found in all Amco products: superior performance, economy, durability, and simplicity with consequent ease of maintenance. The combination of all four is found throughout the complete Amco line. AMCO ATOMIZER NO. 6 The automatically self-cleaning Amco No. 6 micro-spray atomizer de livers a smoke-like spray to a great distance for balanced distribution of humidity. Its fine performance and ease of maintenance make this atom izer popular for new installations and replacements. These units require compressed air for operation and obtain their water supply from a con stant level, fioat controlled tank and piping. . AMCO HUMIDITY CONTROL Model K-2, improved through redesign, maintains room humidity within the closest practical limits under both normal and unusual conditions. An Electro-Pneumatic mechanism, operating in cushion-mounted jeweled bearings controlled by two humidity-sensing membranes, regulates atom izer operating periods. A variable change anticipating mechanism com pensates for mechanical lag and the time required for water vapor to mix with and change the relative humidity of the room atmosphere. This re sults in humidity control within limits not previously attained in a rugged, dependable device. ' . '. AMCO MODEL 35 HUMIDIFIER Ideally suited for areas of light heat concentration, especially where cost of other types of humidification might be prohibitive. Propeller-type fan draws room air into rear of unit and forces it forward around periphery of atomizer disc--thus carrying atomized water into room where it quickly evaporates into surrounding atmosphere. Housed in stainless steel. Re quires only simple water and electrical connections. May be adjusted to evaporate from zero to 22 pounds of water per hour while circulating 1200 cu ft of air per minute. Simple and reliable, it requires a minimum of maintenance. Air Conditions! Bnmidlfyiat Eqsipaaent 71 ARMSTRONG MACHINE WORKS 851 Maple St., Three Rivers, Mich. GUARANTEED: SATISFACTION OR YOUR MONEY BACK Available from Factory Representatives in Major Cities, or Direct from Factory Automatic Steam Humidifiers--Air-Modulating or Electric Operated For Comfort Air Conditioning or Protection of Hygroscopic Materials in Industrial Plants Armstrong Humidifiers are large capac ity, automatic units which discharge dry steam into duct systems or directly into space humidified. Installation is simple. Maintenance is negligible: Advantages of Steam Humidification 1--Steam is - ready-made vapor which merely has to be mixed with the air. 2--Steam deposits no mineral dust such as comes from evaporated water drop lets. 3--Steam can be shut off as soon as the control is satisfied--no over-run. 4--Steam comes on immediately when control calls for humidity. 5--Steam creates no sanitation or odor problems. Duct system and air-handling units are always dry. * 6--With steam there is no accumulation of moisture to promote growth of algae - or bacteria. - 7--Steam eliminates corrosion problems in ducts or fan housing. Armstrong Humidifier Advantages 1--Low cost and large capacity. 2--Minimum maintenance, proved by thousands of installations. 3--Quiet operation. 4--No carry-over or drip. 5--Immediate response to control 6--Low operating expense. 7--Guaranteed tabulated capacities. 8--Selection is simple and easy. 9--Small space required makes duct design easy. 10--Easy installation. Size and List Price Range Air-Operated Units Model Lat Price Cep*city, Ib/hr AM-32 AM-33 DA-34 229.25 316.00 593.00 31 to 150 60 to 320 145 to 1425 Electric Units Model List Price " CL-2 CL-3 CK-4 170.00 295.00 545.00 Ciptcuy, Ib/hr 25 to 76 60 to 170 145 to 1280 Air-Operated Units--When relative hu midity drops slightly below desired level, the pneumatic hygrostat increases air pressure in operator to open modulating valve in proportion to demand. When demand is satisfied air bleed closes the valve. Air-operated units usually dis charge to ducts or are installed in plenums. - Electric Units--When relative humidity drops slightly below desired level, humidistat energizes solenoid to open steam valve and start fan. Steam flows through muffler to atmosphere and is dispersed by fan. When desired humidity is reached, humidistat closes valve and stops fan. Electrically operated units normally discharge directly into atmos phere. Simple duct installations of air . operated units AM-32 Air-Modulating Humidifier complete with strainer, trap and hygrostat. AM -33 similar. CL-2 Humidifier complete with fan and motor, humidistat, fine mesh strainer and trap. CL-3 similar. Automatic Evaporative-Type Humidifiers For Residential, Commercial and Industrial Service where the direct use of steam is impractical- Advantages: BIG CAPACITY---up to 10 pints/hr. AUTOMATIC CONTROL AND OPER ATION--set' it and forget it. USE WITH ANY HEATING SYS TEM--hot water, steam or warm air. FLEXIBLE INSTALLATION--Can be suspended from ceiling, mounted on floor stand, or attached to warm air duct. Enclosure available. DUST FREE HUMIDIFICATION-- "distilled" water vapor is used. LIFE-TIME CONSTRUCTION--Fiber glass tank and corrosion resistant parts. List prices start at $195. Bulletin No. 90S gives further information. Bow It Works--When relative humidity drops slightly below humidistat setting, humidistat starts fan, blowing air across surface of heated water and thence to area to be humidified, or into a furnace plenum. Water level is kept constant by automatic float control. 72 I Air Conditioning Catni Sy. W^~ Air Conditioning CcMnl Sritm> 73 BUENSOD-STACEY, INCORPORATED 45 WEST 18th STREET, HEW YORK 11, NEW YORK CHARLOTTE, NORTH CAROLINA RICHMOND, VIRGINIA Winston-Salem, N. C AIK CONDITIONING-HUMIDIFICATION-CLEANING-VACUUM COLLECTION-CREELS 1. AIR WASHER--Bahnson Type Y and Type DC Air Wash era cool, and provide humidity control. Available m J standard sixes from 6J300 to tSOflOO c/m, they can be provided | with spray systems best suited for the specific application, r WriteTor Catalog IA - 2 TYPE E HUMIDIFIER--A self-contained unit with high evaporative capacity for installation in all types of industrial and commercial spaces requiring automatically controlled hu midification. Evaporates up to 3 gph with 360 degree radial distribution of moisture. Requires only water supply and elec trical connection. Write for Catalog ISA 3 CENTRIFUGAL HUMIDIFIER--A self-contained unit for industrial use. Evaporation up to 12 gph plus directional air flow with fractional horsepower motor. Installed singly, or in groups with individual or group automatic control. Requires . only water supply, drain, and electrical connection. Wnte for Catalog tA 4. TYPE BA-2 HUMIDIFIER--A high-capacity unit for over head in commercial and industrial applications. Ad justable grilles give complete directional control of moist air delivered. Automatically regulated, the unit provides air flow, humidification and filtering. Requires only water supply, drain, and electrical connection; capacity up to 18 gph. Wnte for Catalog I7A 5. TYPE ESC-2 ATOMIZER--A self-cleaning pneumatic atomiser of quality design for direct humidification or supple mentary evaporation. Uses air and water under pressure to pro vide high evaporation and fine spray quality, with minimum air requirements. Modulating control regulates evaporation in' direct proportion to the room requirements. Write for Catalog SA 6. riPTT.T/RS--RaKngin Type C and D Grilles are designed for air discharge with removable core for easier cleaning and access to distribution duct. The air-foil type blades in the grilles are wide-spaced for both horizontal and vertical blade deflection and are individually adjustable by hand for air flow control Constructed of extruded aluminum, blades are mounted on lVv in. centers and are 1V4 in. in width. Type C Grille has Audi type mounting; Type D Grille blade section projects forward permitting unobstructed air flow in distribution duct. Write for Catalog SA 7. HUMIDITY CONTROU3--Bahnson Controls are offered in either electric or pneumatic design. The control consists of a Highly sensitive bumidistat which actuates an electric or pneu matic relay in response to humidity changes in the conditioned area. The humidistat is mounted in an aspirated cabinet which constantly draws a sample of room air over the hygroscopic element. Manual selector switches in the cabinet provide auto matic functioning of motor-operated valves supplying water or to humidifying units. Write for Catalog 9A OTHER BAHNSON MANUFACTURED EQUIPMENT: portable humidifiers, steam humidifiers, air washer suction strainers, spray ncarles, and complete industrial air condition ing systems. In addition Bahnson manufactures vacuum collec tion and cleaning equipment and creels. Write for descriptive literature on your requirements. Tn-Vl. Window-Wall Dual Otic* unit (snowing automatic volume control). Tjrpa H. O.ari.aa.1 DaalDacI auH. BUENSOD-STACEY AIR HANDLING UNITS WITH SELF-CONTAINED AUTOMATIC VOLUME REGULATION Automatic volume control is a self-contained feature of every Buensod-Stacey air handling unit. By simple mechanical means it maintains a constant flow of air through each unit in the system within plus or minus 5% of the desired amount even though static pressure at the' unit's inlet may vary as much as 8" wg. This makes it impossible for any zone in the system to become un balanced. Automatic volume control operates without the need of any outside power source, sensing instrument or complicated arrangement of linkage. SIMPLE TO INSTALL AND ADJUST A screw setting of spring tension at the time of installation and the unit is permanently set for the specified volume. If, after in stallation, a change of air volume is desired, it can be made quickly by adjusting one nut. No linkage. The mixing valve is designed for direct, straight-line movement. On dual-duct units, compressed airfrom a local thermostat controls the mixing valve to provide the desired room temperature. DUAL DUCT AIR CONDITIONING SYSTEMS This method of air conditioning utilizes hot and cold air in parallel conduits. The two streams of air are carried throughout a building separately and are blended in each conditioned zone by an air mixing valve. Temperature is controlled locally by a thermostat. The occupant may select the temperature at which he is most comfortable. Without adequate automatic volume control in each unit zona become unbalanced very easily. It is much like what happens when a shower bath valve is opened on the ground floor of a building and pressure drops on the top floor. Automatic volume control prevents this, TYPE H OVERHEAD UNIT Intended for use above hung ceilings, it supplies air through con ventional side wall outlets or overhead diffusers. SINGLE DUCT AIR CONDITIONING This is Buensod-Stacey's newest air handling unit. It has been designed for use with central systems where the air temperature is pre-determined by zone thermostat and a single stream of air is carried to each zone for distribu tion. When such an arrangement is used, the Type HSD unit, by using a volume regulating device as the valve, saves much field labor normally required for adjustment and balancing of the system. All Buensod-Stacey Air Handling Units, both Single Duct and Dual Duct, are now available in alumi num. Where weight and handling are factors, this construction shows economy, and where corrosion Is a factor, aluminum construction has many advantages. / HIGH PRESSURE DEHUMIDIFIERS The development of a series of dehumidifiers for use with high pressure Dual Duct and Single Duct systems has proven to be essential. These factory insulated, specially braced, sprayed coil dehumidifiers are designed for pressures up to 10" wg. BUENSMMH TYPE V3 WINDOW-WALL UNIT Designed for installation under windows. It upward .. . quietly and without draft. vertically Literature describing the equipment mentioned here is available. To obtain information about it, write Buensod-Stacey or com municate with our nearest sales representative.  74 AIR CONDITIONING REFRIGERATION INDUSTRIAL HEATING Air Conditioning Carrier Corporation Carrier Parkway Syracuse 1, New York MARINE DEPARTMENT 385 Madison Avenue New York 17, N. Y. INTERNATIONAL DIVISION 385 Madison Avenue New York 17, N. Y. Branch Offices and Dealers in all principal cities . air conditioning REFRIGERATION industrial heating 75 Carrier Corporation Carrier Parkway * Syracuse 1, New York Branch Offices and Dealers in all principal cities Refer to page 130 for Carrier Unit Heaters See Sweet's Architectural, Plant Engineering or Industrial Construction Files or write Carrier Corporation, Syracuse 1, New York for specific literature. Weathermakers These .versatile self-contained- air conditioners are excellent for use either singly or in multiples in all types of commercial and industrial buildings. Compact, attractively styled for use in or out of conditioned space, with or without ducts. Heating coils optional. Available in eight sizes, air or water-cooled models with capacities of 3, 5, 7'A, 10, 15, 20, 25 and 30 tons. Year-Round Weathermakers Complete year round air conditioning units for homes and smaller commercial and industrial buildings. All the elements for cooling, heating, filtering, circulation, humidifying and dehumidifymg in one compact package. Air or water cooled models available with cooling capacities from 5 to 7Vt tons; gas beating capacities are from 100,000 to 190,000 Btuh input. Centrifugal Refrigeration For large scale air conditioning^ process refrigeration, direct or indirect cooling of water, brines, hydrocarbons and other liquids. This compact refrigerating machine is comprised of an evaporator, condenser, and multi-stage centrifugal compressor. Available in a wide range of sizes with cooling capacities from 100 to 4,000 tons, for use with motor or steam turbine drive. Hermetic Centrifugal Refrigeration A compact, completely integrated water cooling machine de signed especially for air conditioning or process liquid cooling applications. Features include a sealed, refrigerant cooled motor-compressor unit, automatic electronic controls, low de mand motor circuiting and hydraulically powered capacity regulating vanes. In cooling capacities from 90 to 1500 tons. Single Zone Weathermakers Central station fan-coil air conditioning units for cooling and heating systems using remote sources of refrigeration and heat. Building-block design offers extreme flexibility of application. Adaptable to floor or overhead mounting in horizontal or vertical arrangements. In eight sizes with direct expansion, brine or chilled water coils. Capacities from 2400 to 40,750 cfm. Multi-Zone Weathermakers For air conditioning several zones of a large building with a single unit, using remote sources of refrigeration and heat. The multiple mixing dampers connect to hot and cold air plenums for independent temperature control of each zone. Eight sizes with coils for direct expansion, chilled water or brine - and steam or hot water. Capacities range from 2400 to 40,750 cfm. A heat operated refrigerating machine, using low-pressure steam or high-temperature water to chill water for air condi tioning or process liquid cooling applications. Uses plain water as the refrigerant and lithium bromide as the absorbent. Op eration can be fully automatic from full load to zero capacity. Thirteen sizes in cooling capacity range from 60 to 700 tons. Water Cooling and Condensing Units Completely packaged water-cooling machines include compact assembly of cooler, condenser, motor, compressor, refrigerant piping and control center all pre-engineered, assembled and factory tested. Capacities range from 5 to 139 tons. Compres sors and condensing units for medium and low temperature ap plications range from 5 to 150 hp; direct, belt drive or hermetic. Modular Weathermaster Units The high induction Weathermaster System uses these room terminals with primary air for cooling and ventilating and chilled water for supplemental cooling or heating. In four base unit sizes for furred-in application or with metal enclosures for floor-mounted or wall-hung installation. Adaptable to all types of fenestration, stool heights and wall construction. All-Air Weathermaster Units These ` high velocity room terminals combine efficient sound attenuation with effective control for every type of all-air system currently popular, including dual duct, single duct (with or without reheat), and dual conduit. Five models in six sizes from 50 to 1700 cfm offer choice for under-window or ceiling installation for both exterior and interior zone application. Cooling Towers Carrier induced-draft towers present an extremely compact de sign to reduce operating weight, structural support and main tenance. Galvanized steel construction with plastic fortified cellulose fibre fill insures long service life. Fan has adjustable pitch cast aluminum blades with close coupled, in-line motor drive. Single or multiple cell towers in sizes from' 100 tons up. Evaporative Condensers . Fan-coil type refrigerant condensers for use with refrigerating compressors to supplant water-cooled condensers or cooling towers. Designed for outdoor or indoor installation, they pro vide an efficient, economical means of heat disposal where problems exist on water supply and disposal. The complete range of sizes covers refrigeration capacities from 5 to 250 tons.  76 Air Conditioning <Wr*i Sr< CLARAGE FAN COMPANY Kalamazoo, Michigan Air Handling and Conditioning Equipment Sales Engineering Offices in All Principal Cities Since 1913 Clarage has been a leading manufacturer of air handling and conditioning equipment. By specialising--building a complete line of this equipment exclusively--Clarage has a concentrated `'know how" that means important dividends to the user. (See "Air System EquipmentFans and Blowers" for other Clarage products.) DRAW-THRU MULTITHERMS (Design 1). For both comfort and process applications. Can be arranged to handle applications ranging from simple ventilation to multi-function air conditioning. Horizontal and ver tical arrangements. 12 sizes. Capacities 500 to 35,000 elm. BLOW-THRU MULTITHERMS (Design lj. For central station zone control air conditioning. A single unit can handle different needs in as many as 8 differ ent areas simultaneously. Hot and cold air is mixed to prevent stratification. Horizontal arrangement only. 12 sizes. Capacities 500 to 35,000 cfm. Air Conditioning 0eojormaUc Pnaductu me. 1109 West Broad Street Fails Church, Virginia . Engineer* and Manufacturer* Representatives in Principal U. S. Cities and Abroad Desomatic Products, Inc. manufactures industrial de humidification equipment for commercial and Govern ment use. %77 Refrigeration as well as adsorption units are manu factured for storage rooms, underground caves and mines, cargo holds on ships, laboratories, packaging rooms and for process control. Some applications re quire combination refrigeration and adsorption sys tems, with refrigeration for moisture removal from warm humid air and adsorption for debunudification of medium to low dew-point air. SPRAYED COIL MULTITHERMS (Design I). Draw-Thru type for applications requiring extremely close control of both temperature and humidity, or where continuous flushing of coil surfaces is desired. Capacities 500 to 25,000 cfm. Unit shown with sprayed coil section exposed. HI-STATIC MULTITHERMS (Design 3). Princi pally for conduit type systems where high duct veloci ties and pressures to 8 in. sp are encountered. Hori zontal arrangement only. Cut-away view shown. Capacities 2,500 to 22,000 cfm. Sprayed coil units also available. UNICOIL UNITS. Sprayed coil equipment principally designed for cooling and dehumidifying service in cen tral station air conditioning systems. Capacities, based on 500 fpm air velocity, range from 3,000 to 41,600 cfm. AIR WASHERS. Capillary washer (shown) primar ily for air cleaning efficiency in comfort and process central station air conditioning systems. Equipped with capillary cells. Spray type for comfort air conditioning, dust removal, and product reclamation. . DOR-800 Equipment is built for atmospheric as well as elevated pressures. Standard stock models available as well as custom engineered equipment. Air Flow cfm External Pressure Voltage . Load Kw Reactivation Energy Capacity 70 deg--35 per cent lb/hr Weight, Lbs. Length, Inches Width, Inches Height, Inches Electric reactivation . SOR-g 25 H' W.G. 110 V, 1 Ph 1 Electric H 48 15 13 18 DOR-M 100 H' W.G. 110 V, 1 Ph 1.4* Electric 1 375 64 20 42.5 DOR-100 175 H* W.G. 220 V, 3 Ph 3 Electric 2.5 425 54 20 42.5 DOR-3541 500 1' W.G. 440 V, 3 Ph 9 Electric 7.5. 1150 70 25 60 555353 1500 1' W.G. 440.V, 3 Ph Electric 22 4000 108 61.5 92.6 AC-3000 3000 r W.G. 440 V, 3 Ph . 60* Electric Gas Steam 52 6000 148 81 91 AC-5000 5000 r w.g. 440 V, 3 Ph 100* Electric Gas Steam 87 9500 177 81 91  78 Air CnnAitioninS Ccatrml ud hanson 3301 Medford St. (Division of National-U. S. Radiator Corporation) Factory and General Sales Office . Los Angeles 63, California Representatives in Principal Cities--Domestic and Abroad Manufacturers of Air Conditioning and Refrigeration Equipment REFRIGERATION AND AIR CONDITIONING THE B-I-G LINE-UP ... 28 FULL LINES! d-h AIR CONDITIONING: SPOTAIRE ROOM - by - ROOM AIR CONDI TIONERS: # I d-h LRC's: basic unit, concealed or deluxe cabinet; 4 models, 200 through 600 cfm. #2. VRC's: concealed or deluxe consoles; 4 models, 200 through 600 cfm. #3. d-h HRC's: 3 suspended types, 19 models, 300 through 1750 cfm. AIR HANDLING UNITS: #4. d-h HH-Series: ceil ing suspended. #5. d-h HHV-Series: floor mounted. Both: 14 models, 624 through 28,000 cfm. HIGH PRESSURE BLOW THROUGH:. #6. d-h HCD and HPF: Hot & Cold Deck, 10 models, 1752 through 32,250 cfm. VENTILATING UNITS: #7. d-h AM: 1752 through 32,250 cfm. 9 sizes. . MULTIZONE TYPES: #8. d-h FLEXAZONE: for simultaneous, independent, variable heating, cooling, ventilating; 1752 through 32,250 cfm. 9 sizes. PACKAGED AIR CONDITIONERS: # 9. d-h AECR. with built-in evaporative condenser. #10 d-h SCR: with water-cooled condenser. Both, 7^ through 75 hp. PACKAGED STORE COOLERS: # 11. d-h DYNA- PAC & ROYAL-AIRE: 2 through 15 ton. PACKAGED WATER CHILLERS: #12. d-h CWG: 7H through 75 hp. # 13. d-h CWG-E: attached evap orative condenser. Both 7^ through 75 hp. EVAPORATIVE CONDENSER: #14. d-h PERMA- FAN: 13 models; 5 through 110 ton. COILS: #15. d-h Extended surface; steam, water, DX, Ammonia, Brine. # 16. TYPE "H"; small appli cations, DX or chilled water. COOLING TOWERS: #17. d-h WMT: 13 models, 5 through 100 ton. AIR-COOLED CONDENSERS: #18. d-h ACC: 13 models, 3 through 80 ton. . d-h COMMERCIAL REFRIGERATION: UNIT COOLERS: #19. d-h FLOCOLD UNIT COOLERS: over 34 F; 15 models; 750 through 11,000 cfm. #20. d-h FLOCOLD: under 34 F, water defrost, 11 models, 750 through' 11,000 cfm. #21. d-h FLO COLD: over and under 34 F water-defrost ammonia, 7 models,2000 through 13,200 cfm. # 22. d-h FLX3COLD HOT GAS: 11 models, 750 through 11,000 cfm. #23. d-h SPASAVER: over 34 F. 9 models, 730 through 4400 cfm. #24. d-h HOT SHOT: AUTOMATIC ELECTRIC DEFROST: under 34 F, 6 models, 700 through 3700 cfm. #25. d-h HRC; MEAT CUTTING 6 PACKAGING ROOM UNITS: 14 models, 500 through 1750 cfm. #26. d-h FLOCOLD HOT PAN; FRUIT/VEG./MEAT ROOMS: 11 models, 750 through 11000 cfm. ___ PRODUCT COOLERS: #27. d-h FLOCOLD (FT & CT; FTWD & CTWD; FTAF & CTAF): 9 models; 1314 to 24,000. REPLACEMENT HOUSING: # 28. d-h SPASAVER: kit to modernize on-job unit coolers. COMMERCIAL RESIDENTIAL "HCD" HIGH PRESSURE BLOW THRU "PERMA-FAN" EVAPORATIVE. . CONDENSER Air Condiiioniin**ff . Cntnl Syttcau lfhnmiAinti*i 79 DRYOMATIC CORPORATION 806 N. FAIRFAX STREET, ALEXANDRIA, VIRGINA MANUFACTURERS OF COMMERCIAL, INDUSTRIAL AND HOME DEHUMIDIFIERS Representatives in Principal U. S. Cities, Canada, & Abroad DRYOMATIC manufactures a complete line of automatic dehumidifiers for accurate control of humidity in laboratory, processing, and storage operations. Desiccant type industrial and commercial air divers are produced in a variety of stand ard models, and household dehumidifiers of both the mechani cal and desiccant type are stocked in various capacities. SCHEMATIC DIAGRAM ment on larger models. Air handling capacities range from 25 cfm to 1500 cfm with water removal rates from 1 to 45 lb/ hr. Units in other capacities can be built to meet individual specifications. DRYOMATIC desiccant dehumidifiers operate over a tem perature range from --40 F to plus 120 F. Their particular efficiency at tow temperatures enables them to maintain low dew points without the'use of reheat, making them suited for dehumidification of refrigerated areas in conjunction with existing air conditioning and cooling systems. Special units containing molecular sieve desiccant, for operating condi tions above 120 F, are available. Machines may be installed either outside or inside the controlled area, ana require only electrical power and two simple flexible hose or galvanized duct connections. Write for further details, requesting Inquiry Data Sheet for engineering recommendations or consultation regarding any phase of humidity control. 0ES1CC MODEL 1500--Schematic Diagram showing basic principle of design of all Dryomatic Dry Conditioners DRYOMATIC dehumidifiers are sturdy, time-tested package units which automatically and continuously remove moisture from the air through the use of stable, solid adsorbents such as silica gel and activated alumina; These desiccants are self-reactivated upon saturation by electric heating elements. Regeneration by steam or gas is available as optional equip DRYOMATIC MODEL 1500--adsorption type dehumidi*. fier with steam reactivation, explosion-proof electrical y fittings, and water-cooled after-cooler ' MODEL NUMBER 25'CT 100 105 150 L-400 1500 TYPE ` POWER TYPICAL MOISTURE REMOVAL ADSORPTION AIR FLOW EFFECTIVE AREA (vtpor tealed) Single Bed, Solid Adsorp tion Three Bed, Solid Adsorp tion Dual-Bed, Solid Adsorp tion Dual-Bed, Solid Adsorp tion Dual-Bed, Solid Adsorp tion (for low temp.) Dual-Bed, Solid Adsorp tion 315V, 60 Cycle, Single Phase 115V, 60 Cycle,' Single Phase 115V, 60 Cycle, Single Phase 230 or 208V, Single or 3- Phase 230 or 208 V, Single or 3- Phase. AorY 230, 208, or 440V 3-Phase, AorY 11.9 lb Water/24 hrs @ 90 F & 75% ft. H. 40 lb Water/24 hrs @ 90 F & 75% ft. H. 48 lb Water/24 hrs @ 90 F A 75% R. H. 104 ih Water/24 hrs @ 90 F A 75% R. H. 90 lb Water/24 his @ 40 A 75% R. H. 880 lb Water/24 hrs @ 90 A 75% R. H. 27 cfm 90 cfm 100 cfm 150 cfm 400 cfm 1500 cfm A DRYOMATIC DRY CONDITIONER FOR EVERY DF.HUMIDIFYINC NEED 10,000 cu ft 25,000 cu ft 35,000 cu ft 75,000 cu ft 90,000 cu ft 700,000 cu ft  80 Air Conditioning f5 AIR CONDITIONING CORP. Manufacturers of Air Cooled Fandaire Air Conditioners db Condensers 1815 South Maybelle Tulsa, Oklahoma CHerry 2-9266 tUprae*tatae> and OiOnbatm in Principal Cities FANDAIRE AIR COOLED CONDENSERS Available in through 80 ton capacity Conservatively rated, these condensers can be used on any application . . . either for new installation or as a replacement for outmoded equipment. While designed for outside installa tion, they work equally well inside. Their unique circular coil design delivers far greater operating efficiency than rectangu lar ' units. As standard equipment they incorporate many features normally sold as "extras." Fandaire condensers above are the 3 and 80 ton units FANDAIRE AIR COOLED AIR CONDITIONERS Available in through 10 ton capacity Fandaire air cooled air conditioners are very good for com mercial, residential and industrial installation. The unique circular coil construction delivers far greater operating ef ficiency, than rectangular units. They can easily be nnmhingd with existing heating systems. Fandaiie advanced design in corporates, without extra charge, many features normally sola as "extras." Available with a full five year warranty. FANDAIRE FEATURES on both the air conditioning and condenser units GREATER FIN SURFACE EFFICIENCY The fin* are helically formed around a heavy-wall copper tube with a spacing of eight fins per inch to permit the free pas sage of lint and dust carrying air. This self-cleaning action helps maintain a higher operating efficiency. The shoulder of each fin is firmly swaged to the tube and to the adjoining fin. No foreign matter or corrosion can form between the tube and the shoulder to cause loss of heat transfer even after years of ex posure to the elements. In addition, the shoulder provides a full 100 percent con tact with the tube, guaranteeing the mmimiim amount of heat will be trans ferred to the fin. The fins are pyramidal in shape for sturdiness and to permit the best possible dissipation of the heat. TRUE COUNTER FLOW True counter flow is an action in which the hot refrigerant is gradually cooled by Sowing against (or counter to) the ruling medium. In other words, the refrigerant Sows hot to cool, or counter to the cooling medium whicn Sows cool to hot. In Fandaiie units, the hot gas enters the condenser tubes at tbe inlet header inside the condenser and makes five complete circles before leaving the tube at tbe outlet header. Since the cool air enters the condenser around the periphery of the coil and is pulled through the bank of tubes, the coolest u gas is always in closest contact with the ~ tubes carrying the coolest gas. This pro vides tbe best possible counterflow and assures a greater mean temperature at all times, giving a higher rate of heat transfer, lower condensing temperature and a greater degree of sub-cooling. POSITIVE CONDENSATE . DRAINAGE Each row or layer of tubes slopes down ward at a 30 deg angle. This means the tubes at the outlet header are lower than the tubes at the inlet header. This slope assures a better drainage of all conden sate as fast as it forms on the tube wall. No pockets of compressor oil can form to act as an insulator between the hot gas and the air cooled tube walls. STRAIGHT THROUGH FLOW Each circuit consists of one continuous length of a single tube which completely eliminates ALL pressure drop caused by return bends. Laboratory tests have shown that up to 60 percent of the pres sure drop normally found in rectangular units is due to the short radius return bends necessary in their construction. Fandaire's long-sweeping, one-circuit construction approaches the almost non existent pressure drop of a single pass unit while retaining all the advantages of a five-pass unit. VERTICAL AIR DISCHARGE Vertical sir discharge is part of the standard construction. -No air scoop or wind deflector is necessary. This vertical air discharge eliminates any tendency to re-circulate hot air and is a "must" in multiple installations. With Fandaire units there are no dead spots to be found on the face of the coil since the air is drawn around the circumference of the coil. Wind from any direction can be used, it is not necessary to face tbe units in the direction of the prevailing wind. HOUSING All Fandaire models are weatherproof. They are housed in attractive, corrosion resistant housings of aspun construction. Models up to ton are made of alumi num alloy--all other models are gal vanized after construction for a durable, maintenance free finish. The air condi tioners are supplied with a two-piece, wrap-around skirt. Many other features, normally sold as "extras" on other units, are incorporated in the standard Fandaire design. These include legs, mount ing brackets, fan guards. MOTORS AND FANS Either direct drive or belt drive weather proof or totally enclosed, ball bearing, permanently lubricated motors are used on all Fandaire models. Fans are axial flow type and are constructed from plated, heavy-duty corrosion-resistant steel or aluminum. ` Air Conditioning kfripm. 81 Allied (jiemical GENERAL CHEMICAL DIVISION 40 Rector Street, New York 6, N. Y. genetroriManufacturer of Super-Dry Refrigerants "Cenetron" 12--White Label-- CCLF*--Dlchlorodifluoromethaiie; and "Cenetran" 22--Green label--CHCEFi -----MnnivlilnmHiflnnmmrttlnj. Used in virtually all types of refrigerationand air conditioning equipment, large and small, household and industrial, direct and in direct expansion systems. Typical unite in which "Genetron" 12 and 22 are used: refrigerators, freezers. frozen food lockers, window air con ditioners, home or office console - units, large custom-built units-for commerical comfort or industrial process, large store units, mobile units for transportation equipment, large home unite for addition to present hot air heating systems. "Genetron" 11--Orange Label-- CCIgF---- Tridilnfnmftnn<liMramMlianL SELECTED PHYSICAL DATA Selected Physical Data (Performance based on 5*F genetron evaporator temperature and 89*F 11 geaetroe 13 geaepn Cbenueal Formula Moleculir Weight ` BotUng Pt. (*F) at 1 Atm- Pm- aure Evaporator Pleasure at 6*P (png} Condensing Pressure at IFF CCLF 187.4 74.7 84.0* 1.4 CClrFi 180.9 -81.0 . CHClFt 88.5 -41.4 11.8 93.3 . 88.9 IS0.8_. Freezing Point (*F) at 1 Atm. Pleasure Critical Temperature (*F) Critical Pitisum (pal absolute) Compressor Discharge Tempera* -188 SS8 635 113 -3S3 834 807 . 101 -850 805 718 131 gamr&oQ CsCti?> 187.4 ' 117.6 87.9* 18.9* -31 417 485 88 geaetnm CiCliF, 170.9 37.6 u.e* 81.7 -78 394 478 88 For industrial commercial refrigera tion and air-conditioning systems using single or multi-stage centrifugal compres sors. Can also be used for either direct or indirect expansion-type systems. "Genetron" 113--Purple Label C*CLF*--'TrichloroCrafliioroetliane. Used in 50-ton and larger centrifugal compres sors, primarily for large comfort cooling systems, brine cooling systems and other commercial and industrial air condition ing and refrigeration systems. "Genetron" 114a--Blue Label-- C*CLF--Diehlorotetraflnoroethane, Used in centrifugal and rotary compres sors for commercial, industrial and house hold refrigeration. QUICK FACTS on "Genetron" Super Dry Refrigerants: Guaranteed exceptionally low moisture content Compression Ratio (88*F/S*F) Specific Volume of Saturated Vapor at 6*7 (eu ft/lb) Tafrnt Best ot Vaparimtion at 5*7 (Btu/lb) Net Being. Effect o1 Liquid-- *P/5*F (Btu/lb) Specific Heat of Liquid at 88*7 (Btq/lb*7) 8pedfic Heat of Vapor at Con* etsnt Pleasure of 1 Atm. A S8*F (Bba/lb*F) Specific Heat Ratio at 88*7 A 1 Attn, (k - Cp/Cv) Coefficient of Pcrforma^e Horespowtr/Ton Refrigeration Refrigerant Circulated/Ton Re frig. (Iba/mia.) Liquid Ctreulated/Ton Refrig, (ea to/min.) Compressor Displacement/Ton Being* (elm) Toxicity (Underwriters' Labors* tones Group No.) FtammebflitT A * Inches of memury nernm. 8.84 13.87 84.0 87.8 0.810.11 1.14 8.09 0.937 3.90 88.0 80.38 SA None 4.08 1.48 68.3 80.0 0.84 O.U 4.06 1.85 88.6 60.3 ' - 0.34 Q.t5 8.03 87.04 70.8 53.7 0.11 O.U 1.14 4.70 1.003 4.00 85.0 8.83 8 Noae 1.18 4.80 1.011 3.89 68.0 8.60 SA Non* 1.08 4.88 0.960 3.73 68.5 tOO.76 4-6 Noae 5,83 4.01 60.3 43.0 0.83 0.10 1.01 4.00 1.025 4.85 88.7 18.78 5 None Non-corrosive to standard equipment materials . Non-toxic, non-flammable, stable, safe Critical andfreezingpoints well outside rangeof operating uses ' - Solvent action on oil helps prevent solidi fication or congealing of lubricant ' Freely interchangeable and may be mixed in any proportions with com parable fluorinated hydrocarbons meeting the same strict refrigerant specifications - Aid in lubrication of equipment; gener ally miscible with oil Available everywhere from refrigeration wholesalers throughout the country  82 Air Conditioning GENERAL ELECTRIC AIR CONDITIONING DEPT. Tyler, Texas Atlanta 3, Ga.--410 Red Rock Building........... JAckson 3-7447 Birmingham 9, Ala.--2846 South 18th St........TRemont 9-3466 CEILING-MOUNTED. Chicago 54, III.-- ' Splitsystems.Condensing The Merchandise Mart, Room 1117........ DElaw&re 7-2137 unit air-cooled, weather Cleveland 31, Ohio--Shaker Heights, 6900 Granger Rd.......................................................LAfayette4-4406 proofed for remote instal Dallas, Texas--Suite 2001, Trade Mart, . lation, indoors or out. 2100 Stemmons Freeway......................................... Riverside8-6733 Detroit 21, Mich.--16247 Wyoming Ave.......... Diamond 1-1459 Small, compact, light Houston, Texas--2425 Broad St.........................Midway 4-5401 weight air conditioner Jacksonville 5, Fla.--5266 Highway Ave........EVergrceh 7-3571 Kansas City 15, 3260 North 7th St., Trafficway....................MAyfair 1-3700 includes blower, evaporator filter. Capacities: 2%, 3,4, 5, IVz and 10 tons. linden, N. J.--1611 Elizabeth Ave. West........ WAbash 5-3600 Los Angeles 21, Calif.-- , Zone-by-Zone installation permits individual con 2958 East 46th St........................................................MAdison7-4602 trol and servicing of each area. Accessory steam Louisville, Ky.--Appliance Park, and hot water coils available for winter heating. Memphis, Tenn.--500 South Front St............... JAckson 7-5531 New Orleans 19, La.-- 4221 Bienville St................................................GAivex 5-5771 New York 22, N. Y.-- 570 Lexington Ave., Rooms 301-2-3............... PLaxa 1-1311 New York 16, N. Y.--150 East 42nd St................PLaxa 111311 International General Electric Company ' Philadelphia 20, Pa.-- 5660 Rising Sun Ave........................................ Pilgrim 2-2880 Salt Lake City, Utah--200 South Main St........ EMpire 4-1891 Burlingame (San Francisco), Calif.-- 1649 Adrian Rd..................................................OXford 7-3321 Seattle 4, Wash.--705 Second Ave........................... MAin 4-8300 Washington 5, D. C.-- 777 14th St., N. W., Room 917............... Executive 3-3600 WHOLE-HOUSE RESIDENTIAL AIR CONDITIONERS C00UNG COILS to convert warm-air furnaces into year'round whole-house air conditioning. Type '`A" for. low headroom, upflow or downflow--type "F" (fiat) for upflow, downflow, horizontal. 5 sizes, 24,000 BTUH to 60,000 BTUH. FOR STORES, OFFICES, FACTORIES FLOOR MODELS. Self-contained--water-cooled. Capacities: 3, 5, 7%, 10,15, 20,25 and 30 tons. In space air distributor for 3 to 15 ton units. AIR HANDLING UNITS. Horizontal (shown with optional air diffuser) and vertical. For residential and lightcommercial application when teamed with remotely installed G-E air-cooled condensing unit. 2% through 5 tons. CEILING-MOUNTED. Self-contained--may also be shelf-mounted. Air-cooled in 3 and 5 ton capacities --water-cooled in 3, 5 and 7% tons. . Central S;ittal GENERAL ELECTRIC REMOTE CONDENSING UNITS. Factory-sealed, air-cooled, weatherproofed. For outdoor installa tion. For use with G-E cooling coils or air handling units. 6 models, 2 through 6 tons. 83 STEEL GAS FURNACE. Smallest unit takes only 15" x 28" floor space. Minimum clearances ap proved by AGA .--sides, rear and combustible floor ing, zero--front and flue, 6"--above plenum, 1", Ideal for closet installation. Simplified wiring, quiet blower,, advanced cast-iron burner design, "Ther mal-Trap" heat exchanger. Two types--one for normal heating and air conditioning, one for above-average cooling loads. BTUH input (upflow and down flow), 75,000 to 150,000 --(hori zontal), 70,000 to 140,000. PACKAGED COOLING UNIT. Compact, air-cooled, self-contained--for homes with or without ducts. Decorative diffuser-filter frame for commercial in-space installation. Install in attic, crawl space, cellar, hallway--on roof, slab--through transom, wall. 2, 2Vt, and 3 ton sizes. ALL FURNACES "grow" into year 'round wlflle- house air conditioning by addition of G-E cooling coils. All handsomely styled in two-tone grav. HOME HEATING UNITS OIL FURNACE. High-pressure gun burner and other standard parts^fpr easy servicing, re placement. Quick-heating "Vertifin" heat exchanger--de pendable safety features. Smallest model takes only 28" x 22" floor space. All models fire-tested, assembled, wired at factory. BTUH output, upflow, 84,000 to 168,000 -- downflowhorizontal, 84,000 to 112,000 IMPERIAL GAS FURNACE Cast-iron "Pinpoint" heat exchanger provides quick, economical heat. Simplified wiring, quiet performance, rugged construction. Small est unit takes only 21" x 30%" floor space. BTUH in put (upflow), 90,000 to 210,000. COOLS WITHOUT WATER, heats without fuel, all-auto matic. Capacities (self-con tained) , 2% and 3 tons-- (split systems), 2%, 3 and 4 tons. Weathertron not available in all states. . AIR-WALL* REGISTER SYSTEM R*S, Trademark of General Electrie Company G-E'S perimeter system for distribution of conditioned air blankets walls with warm air in winter, cool in summer. No drafts. WATER COOLERS PRESSURE AND BOTTLE TYPES. Hot and cold com binations with and without refrigerated compartment. Cold water models with and without.refrigerated com partments. Widest selection all safeguarded by G-E's protection plan. ALL PRODUCTS PROTECTED BY A GENERAL ELECTRIC WARRANTY General Electric Company, Air Conditioning Department, Tyler, Texas.  84 Air Conditioning . BU UaltiS, eOUils, EttfwsAthirc aCawdduonMmn ,' Governair Corporation 4840 North Sewell, Oklahoma City 4, Oklahoma COVERNAIR "Satisfabricated" Air Conditioners SELF-CONTAINED AIR CONDITIONERS-compIetely packed air conditioners with evaporative condenser. Ready for connection to duct system--3 through 100 tons--multiple circuit refrigeration systems included--copper fitted condensers available. "SATISFABRICATED" for numerous choices of components and models. SELF-CONTAINED MULTI-ZONE AIR CONDITIONERS-- with evaporative condenser. Zoned conditioner section---hot and cold deck, with mixing dampers for each zone. Sizes iVt through 80 tons-- multiple circuit refrigeration sys tems included. SELF-CONTAINED CHILLER UNITS Standard equipment includes heat exchanger and built-in capacity reduc tion at no additional cost. 68 combinations available from 10 basic models. Capacity 10 through 120 tons. Factory tested before shipment. ' CABINET MODELS AVAILABLE with built-in or remote evaporative condenser. AIR UNIT CONDITIONERS Available in horizontal GHC unit (shown), or GVC vertical unit. From 3 through 150 tons. In 2, 4, 5,6,8 or 10 rows of coil depth. Vari able face velocities from 400 to 600 fpm. FAN AND COIL CABINETS -- cooling, heating, humidifying, dehumidifying, ven tilating, 1 through 100 tons, 500 to 40,000 cfm, vertical or horizontal types. Governair, multi-zone fan and coil units are available in sizes ranging from 5 to 80 ton capacity, suitable for individual zoning. BLAST COILS--direct expan sion, water steam--hydraulically expanded tubes for close fin spacing --mechanically expanded tubes for wide fin spacing--copper or alumi num fins--complete range' of sizes. The copyrighted term "Satisfabricated" is defined as follows: A method of purchasing air condition ing equipment which allows the en gineer to determine the completed unit, fulfilling specified require ments and dimensions by selecting the specific components to be used. . . ziir Conditioning Upltl, Caila Tn Kennard Division of American Air Filter Co., Inc. 1270 North Price Road St. Louis 14, Missouri 85 KENNARD. PACKAGED LIQUID CHILLERS 20 to 160 tons. Water and electrical con nections only required for installation. Unloaded starting and multi-step capac ity control. Automatic chilled water temperature control. ' DUAL DUCT CENTRAL STATION AIR CONDITIONING UNITS Normal and High Pressure Types, 7 sizes. Cooling Coil Face Areas up to 60 sq ft. CENTRAL STATION AIR CONDITIONING UNITS 16 Sizes, 300 to 38,000 cfm. Cooling and heating coils up to 60 sq ft face area. Horizontal or Vertical. Single and double fan units. Flexibly adapted, by combining optional elements, to provide all or part of the air conditioning cycle, comfort or industrial. Choice of blower discharge positions simplifies ductwork, eliminates turns. LIQUID CHILLERS Direct Expansion, Shell and Tube Type. Internally-finned tubes. Capacities 2 to 200 tons. Kennard design eliminates re frigerant head gasket, prime source of refrigerant leakage. Controlled distribu tion of refrigerant to tube circuits. Rapid, positive response to control. Posi tive oil return. * ... HEATING AND VENTILATING UNITS 16 Sizes, 300 to 48,000 cfm. Horizontal or Vertical, floor or wall mounting or ceiling suspension.. Hot water or steam coils. Choice of blower discharge positions. MULTI-ZONE CENTRAL STATION AIR CONDITIONING UNITS 9 Sizes. Cooling Coil face areas up to 60 sq ft. Choice of Direct Expansion or Chilled Water Coils for Cooling, and Steam or Hot Water Coils for heating. Standard units furnished with Zone Con trol Dampers and multiple individual zone outlets. COOLING TOWERS Outdoor or Indoor, 15 to 75 tons. Com pletely corrosion-resistant. Hot-dipped galvanized after fabrication. Stainless steel or bronze fastenings used through out. Simple disassembly of blower, spray deck and sump pan sections facilitates field handling, hoisting and rigging. SPRAYED COIL DEHUMIDIFIERS 56 Sizes, Coil Face Areas up to 81 sq ft. Cooling, dehumidifying, evaporative cooling, and washed air, all in one com pact unit. Direct expansion or water coils for cooling; steam or water coils for heating. FINNED COILS Direct Expansion Coils, Water Coils, Steam Distributing Tube i Coils, Standard Steam Coils. Sizes up to 48 in. wide, 156-in. finoed length. . EVAPORATIVE CONDENSERS 18 Sizes, 16 through 125 tons. Outdoor or Indoor. Fan wheels and housings, and sump pan, hot-dipped galvanized. Non corroding, cleanable, swirl-type spray nozzles. Liquid sub-cooling coils avail able. ' HSSXG: @oV tDQj CENTRAL STATION AIR CONDITIONING UNITS cooling -- hooting -- dehumidifying -- humidifying. 38 sizes*--1 to 175 tons --400 to 52,000 cfm. Ceiling, floor types. All occessorles. Bulletin 30 REMOTE ROOM AIR CON DITIONING UNITS -- Permit Individual climate selection. No duct* work, only simple piping and ceiling type units. neeBdvelhdt.iiF, lo3o3r MULTI-ZONE UNIT-- Com plete winter and summer functions. Individual zone control--1,300 to 37.000 cfm. Stfta/c 31 COOLING TOWERS AND EVAPORATIVE CONDENS ERS-- Industrial and commercial towers--20-100 tons--induced draft, wetted deck surface, water spray-- indoor-outdoor. 4*Thrtfti-TowerM adap tation for residential, light commercial use--2-16 tons. Evaporative condensers, 3 to 250 tons --all refrigerants--all prime surface ceils--no fins--quiet--indoor-outdoor. Also air cooledBcuolnledteinn,seSrOs.,55, 60, 61 INDUSTRIAL COOLERS -- 15 unit sizes--1,000 to 26,500 cfm --water, electric and continuous brine spray defrosting. Ceiling, floor types. BvOetia 40 BLAST COILS--Air conditioning -- industrial refrigeration--heating. Any material--all refrigerants--every application. Pressure-expanded stag gered tubes,continuous plate-typefins. SuNetios 10,11 SPRAY COIL DEHUMIDI FIER--washing, cleaning, humidi fying, dehumidifying, heating and cooling. Air volumes from 600 to 74.000 dm. BvBvtm 37 UNIT COOLERS-- water and electric defrosting--manual or auto- mafic control. Bolfdta. 21, 22 Atr ClfiTlditlOTltTlS Ctttnl Srmau NIAGARA BLOWER COMPANY 87 Service and Development In Air engineering for Over 40 Years Factory and General Offices: Buffalo, N. Y.-- Executive Offices, New York, N. Y. AIR ENGINEERING Bulletin describes Niagara equipment for beat removal by the air method, cooling liq uid* and gases, coodcosing rtpon; beat and moisture control by complete function sir conditioning; vapor equilibrium by direct liquid contact. BULLETIN No. 155 AIR CONDITIONING Bnlletios describe' methods of obtaining precise control oftem perature and moisture ro help tou make your product in any climate at any season. Dlustrated with diagrams mod photographs. BULLETIN No. 122 BULLETIN No. 112 COOLING AND FREEZING Bulletin describes Niagara "No-Frost" Method; production of low air temperatures for industrial uses, such as testing or pro cessing at extreme subaero temperatures or forcoocrol ofairmoist ure in atmospheres be low the freezing point of water. BULLETIN No. 95 "NO-FROST" METHOD Butlerio describes Niagara "No-Frost" Method of refrigera~don for food freezing, frozen food warehous ing, fresh food pre cooling cod storsge, giving completely au tomatic operation with no shut-down for de frosting. BULLETIN No. 105 AERO HEAT EXCHANGERS Bnlletios describe evaporative cooling apparatus thsc keeps control of temperature within two degrees by modulating the low of air. Saves 95 % ofcool ing water. Provides beat when needed. BULLETIN No. 120 BULLETIN No. 124 BULLETIN No. 152 AERO AFTER COOLERS Describes equipment for cootiog compressed air or gases, bolding temperatures below ambient atmospheric temperature to prevent condensation of mois ture. Include* applica tion to air liquefaction BULLETIN No. 150 AIR CONDITIONERS Bulletin describes Niagaracoil surface air conditioners for use widt any refrigerant, offering any selection of air conditioning fuactioos. Models available to match any load requirement. BULLETIN No. 155 FAN COOLERS Bulletin* describe Niagara Fan Coolers, dry coil and brine spray types for use with briue, ammonia or freon refrigerants. BULLETIN No. HO BULLETIN No. 158 AERO VAPOR CONDENSERS Providing high vac uum. independent of a Large supply of cool ing water. Solves the problems ofwater sapply and disposal. Fully automatic. Save* pow. er. Saves steam. BULLETIN No. 159S DRYING AND DEHUMIDIFYING Bulletins illustrate air conditioning cabinet and drying installa tion* including sicca tive coatings, paper, plastics, provisions, confectionery, phar maceuticals, mecallur- BULLET1N No. 88 BULLETIN No. 112 AEROPASS CONDENSERS Bulletins describe evaporative refrigerant condensers providing protection against scaling of tubes, con trolling of compressor bead pressures, saving condenser wster. BULLETIN No. Ill BULLETIN No. 125 BULLETIN No. 151 LIQUID COOLERS Cooling for chilled water or solutions, with elimination of freeze-cpdamage, aritb rapid chilling of Urge fluid volume and dose temperature control. BULLETIN No. 104 HIGH PRESSURE STEAM HEATING Bolletin describes method completely utilizing both the sen sible and latent heat of high pressure steam. Trustworthy, longlived equipment for bearing or process. BULLETIN No. 109 REFRIGERANT CONDENSERS Bulletin describes evaporative conden sers for ammonia and freon refrigerants of fering high condensing capacicy at a low cost per too in power cost and upkeep as well as low installation cost. BULLETIN No. 157 MOTOR BLOWERS Balletin describes blowers in two series sp ro )Vt' static pres sure. Available in one, two and three fan as . aemblies. Applicable to ventilating, drying, air conditioning. BULLETIN No. 89 For complete information, copies of Bulletins, Engineering Data, address NIAGARA BLOWER COMPANY* 405 Lexington Ave., New York 17, N. Y. Niagara District Engineers are located in principal cities. I }'  88 Air Conditioning . Cmit>i sr PARKS-CRAMER COMPANY Fitchburg, Mass. Charlotte, N. C. Industrial Humidifying and Air Conditioning Since 1904 Atlanta, Ga. 7 1Air Conditioning * Catnl S MB PctimHiStrtiwi tbit* 89 PITTSBURGH LECTRODRYER DIVISION - ef MCGRAW-EDISON COMPANY '4 "f P. O. BOX 1766 PITTSBURGH? 30, PA. AIR WASHER CERTIFIED CLIMATE A complete system for conditioning the factory atmosphere, with positive air circulation and controlled ventilation. One or more air washer units. High humidifying and evaporative cooling capacity. Heating, filtering and refrigerated cooling where needed. Ducts with adjustable outlets distribute condi tioned air uniformly. Slight air pressure also improves uni* formity. Centralized maintenance. Used with or without booster humidification. Under gradual acting automatic con* troJ. Multi-speed control of fan improves economy. Central Station Air Washer Units. Nozzles and Self-Cleaning 'Tank Screens for Centra! Station Air Washers. Improved system of forced air change and distribution used with direct humidification. Insures fixed uniform humidity and and maximum evaporative cooling. Amount of air change, and operation of humidifiers under gradual automatic control. For complete new installations or for supplementing existing direct humidifying equipment. Includes heating, refrigeration, filter ing, where needed. With or without ducts. DIRECT HUMIDIFICATION Atomizer humidifier for all uses. Evaporative capacities up to 16 pounds of water per hour. Turbomatic--gravity type, onana-off, fixed output, several sizes. GraduVac--full range modulating control, applicable to any gravity type atomizer system. Gradumstic--water under pressure, lull range modu lation. All types--self-cleaning, used alone or with Airehangers or as boosters for air washer systems. LABORATORY AIR CONDITIONING An essential of good testing is adequate and dependable air conditioning. Accuracy in testing is maintained only when samples and room atmosphere are free from fluctuations in both temperature and humidity. A vertical or horizontal unit is located within or adjacent to the laboratory. Includes equip ment for heating, humidifying, debumidifying, refrigeration circulation, filtering. Adjustable recorder-controller. Heat by steam or electricity. CERTIFIED CLIMATE REGULATION For humidity and temperature. Gradual acting, or on-and-off. Psychrostat-rwet and dry bulb. Hygrostat--absorption type. Both types sensitive, rugged, reliable. Autographic recording included where desired. INDEPENDENTLY CONTROLLED DEHUMIDIFICATIQ^f FOR INDUSTRIAL APPLICATIONS AND AIR CONDITIONING Air-conditioning (CH-type) Lectrodryers provide an efficient, economical means of dehumidification in industrial areas in winch the material in process or in storage requires a relatively dry atmosphere. Lectrodryers are used for this purpose in pharmaceutical houses, food processing plants, metal storage areas, and many types of packaging plants. The uninterrupted production, higher quality and safer storage made pos sible by the introduction of dry air in such applications often save the user many times the cost of the Lectrodryer. In addition, operating costs are negligible. The dehumidification process is continuous and com pletely automatic. It is completely independent of any air-conditioning apparatus that might serve the same general area. If cooling is desired along with dehumidifi cation--either for comfort air conditioning or in con junction with an industrial application--an after-cooler is mounted directly on the Lectrodryer. Wide Range of Sizes and Capacities Relative humidities of 35 percent or lower are obtained with standard CH-type Lectrodryers. Capacities range from 350 cfm to as high as 15,000 cfm. Moisture is re moved from the air by means of a solid adsorbent-- activated alumina--with automatic reactivation being ^ accomplished by gas, steam or electricity. Lectrodryers require almost no maintenance. The only moving parts are the motor and blowers, and the valve drive mechanism. Units are shipped completely as sembled, ready for easy installation. All are manu factured to rigid standards that have made Lectro dryer one of the world's foremost manufacturers of adsorbent dryers. Write for full details.  90 RECOLD CORPORATION 7250 E. Slauson Awe., Los Angeles 22, Calif. Air System Equip: MULTIZONE AIR CONDITIONING UNITS Capacities from 840 through 36,000 CFM. Intermediate coils provide 27 sizes in 9 basic cabinets. Cabinets may be horizontal or vertical. Zones may discharge horizontally and/or ver tically. One unit simultaneously heats and cools up to 28 zones. Units are available with backward curved wheels for static .pressures up to 6 in. Units are also available less zone dampers for double duct high or low velocity systems. Catalog S5C7c Horizontal Air Conditioning Unit , AIR CONDITIONING UNITS Horizontal and Vertical Air Conditioning Units. Capacities from 736 through 36,000 CFM. Intermediate coils provide 30 sizes in 10 basic cabinets. Cabinets may be horizontal or verti cal . Units are available with backward curved wheels for static pressures up to 6 in. Both Horizontal and Vertical units are available with the following accessories: Insulation is }i in. or 1 in. fiberglass at tacked to panels with special mastic adhesive. Flat filter sec tion for cleanable filters, removable from side, top or bottom on Horizontal units, or sides on' Vertical units. Angular filter sec tion for disposable filters, removed from sides. Face dampers for coils. By-pass dampers. By-pass section. Spray humidifier. Mixing box and dampers. ' Vertical Air Conditioning Unit Catalog S4C7c DRI-FAN EVAPORATIVE CONDENSERS & COOLING TOWERS Capacities from 3 through 233 tons. Fan scroll assembly handles only dry air. Patented features include: clog-proof "bleed funnel," free-sliding "access doors," and "comer con struction" that provides complete accessibility. Dri-Fan Evaporative Condensers are available with multiple circuiting and may also be used as jacket water coolers. Complete water cooler selection data appears in the catalogs listed below. . Dri-Fan Evaporative Condensers Catalog S0C8c Dri-Fan Evaporative Cooling Tower Catalog 8lC7a r>atrl &Y** * (fail CMln RECOLD CORPORATION 7250 E. Slauson Ave.,Los Angeles 22, Calif. ,91 DRICON AIR COOLED CONDENSERS Capacities from 5 through 40 tons in seven cabinet sizes. Large, slow speed, belt-driven fans. Adjustable angle iron stand. Balanced circuiting. Multiple circuiting is also available. Com plete water cooler selection data appears in the Dricon Air Cooled Condenser Catalog. Catalog 94C8a HEATING AND COOLING COILS Each coil is especially circuited to insure a completely active coil for each individual application. Types of coils include: steam, water, direct expansion, non-freeze steam, heavy duty, low capacity, cleanable tube water coils and copper tube aluminum fin or copper tube copper fin coils. Steam Catalog 5/C7a . Direct Expansion Catalog SSC8a Water Catalog S8C8a RE UNITS 1 ton capacities, silent, compact, individual room units. Units are available circuited for water or direct expansion refrigerant. Standard equipment on Recold RE units includes: vertical bar adjustable grill; grill extension; filter box and filter; two speed switch and wall plate. Coils and drain pan are reversible for either right or left hand connections. Catalog 66C8a PATENTED "CORNER CONSTRUCTION" FOR COMPLETE ACCESSIBILITY Recold's exclusive "corner construction" is used on all evaporative condensers, cooling towers, air conditioners and product coolers. ELECTRICALLY WELDED ANGLE-IRON FRAME All concentration of weights, such as motor mounts, lifting channels, bearing, legs and coils are connected directly to the frame.  92 Air Conditioning Central SrcMrni H. H. ROBERTSON COMPANY 2400 Farmers Bank Building Pittsburgh 22, Pennsylvania ROBERTSON Q-AIR FLOOR SYSTEM Robertson Q-Air Floor is cellular steel sub-floor construction that incorporates within its thickness structural, load-bear ing cells that are available as electrical raceways, plus larger structural cells for use in connection with high velocity, dual duct air conditioning. (See cutaway illustration at left.) These special, load-bearing eells can be adapted by tbe air conditioning contractor to transport air' from horizontal supply ducts to mixing units for discharge into the room. In Robertson Q-Air Floor, use of the floor cells for air pas sages reduces the space between ceiling and floor above. Overall building height can be reduced (without sacrificing ceiling height) by running the secondary supply headers through the web of the horizontal beams instead of below them. Great savings in power consumption, too, are a result because of the reduced cubage of the buitdiog. Except for peak summer cooling periods, Robertson's SEASONAL CHANGEOVER feature keeps the power requirements at about 65 percent of top consumption. As with conventional dual duct systems, Q-Air Floor requires a central plant and a return air system. Except for the change in width of occasional cells, Robertson Q-Air Floor is similar to standard Q-Floor--a product having the experience of 27 years and more than 15,000 installations behind it. Cell depth is the same and the 12-in. unit width of tbe large cell fits into the 6-in. Q-Floor module. Employment of cells to carry air is simply another use added to the widely accepted Q-Floor principle of using cellular steel units for load-bearing and electrical distribution. The unique Robertson Aerator--shown below--is an ingenious piece of apparatus. In addition to its normal function as a mixing box, in which air from the hot and cold sides of the system is mixed in response to the setting of a thermostat, it also makes possible the conversion of the hot side for sup plemental cooling use during the hot months of the year. This "seasonal changeover" device is the heart of Robertson Q- Air Floor and no other system has it.* ' tieKt im Air Crtlu Om* dirtctmm isUaam htrtfirua&iitity. Air Conditioning 93 M. BLAZER & SON PASSAIC NEW JERSEY Manufacturers of Air Conditioning, Refrigeration, Heating and Ventilating Equipment Air Handling Units Custom fabricated air handling units for heating, ventilation and air condition ing. Available as illustrated in types "A" or "B". Type "A". Made in horizontal or verti cal units in 39 cabinet sizes, in 1, 2 or 3 fan assemblies, handling from 400 to 50,460 cfm at pressures up to 3 in. WG. Type "B". High pressure tvpe. Up to 9 in. WG sectionalized. factory assem- Type "B" bled air handling units, in dry coiforsprayed coil type with double insulated casings, access plenums, filter plenums, mixing and return air plenums, etc- In capacities to 28,160 cfm at 9 in. static. All units are available with steam or water heating coils, freon or water cooling coils and various filter media and arrangements. Humidifier, damper and recirculating spray assemblies, various insulations, motors and durable double casing construction. Made in Multizone and Hot and Cold Deck biowthrough types. Also specially designed to fit space limitations. * Self Contained Unit Cooling Towers Mechanical Dehumidifiers Self Contained Air Conditioning Units Complete with refrigeration compressors, built-in evaporative condensers or water cooled con densers for use with remote towers or city water. Also available with receivers only for use with remote air cooled condensers. All units are completely piped, wired and shop-run before ship ment. Available with any or all modifications listed under other equipment shown here. Can be ordered also in roof mounted units for outdoor duty with air cooled condensers and special insula tion. In sizes from 5 to 100 tons. ' Cooling Towers All metal inside and outside and completely fireproof. In sizes from 10 tons up to unlimited thou sands. Very good-for cooling water with air through any range to a 7 deg approach to wet bulb. Available m transite paneled casings, galvanized steel or stainless steel- Entire casing is paneled for easy.access into interior. Designed to require minimum maintenance. Requires the least floor area of any large tower with w&ter loadings up to 7 gpm per square foot floor space. Evaporative condensers and coolers in similar construction are available for any type of cooling or condensing application. * Mechanical Dehumidifiers Utilize Freon compressors. In sizes from 5 to 60 tons, air handling from 640 to 11,850 cfm and mois ture removal to 1,600,000 grains of moisture per hour at dewpoints to 36 deg. Greater capacities down to --25 deg dewpoint by spraying etnylene glycol over cooling coils to prevent frost. Double evaporator type with automatic defrosting also available. Completely wired, piped and shop-run. Heating and Cooling Coils -Helically finned type in copper, aluminum, carbon or stainless steel for all kinds of installations. Heating coils may be ob tained for steam in standard and non-freeze types and water in regular or high temperature, high pressure type. Cooling coils Tor Freon, ammonia or brine in direct expansion, flooded, and standard or cieanable types for water. Available with from 1 to 36 tubes high, 1 to 30 rows deep, 6 in. to 180 in. finned length. Made in steel or non-ferrous casiQgB. All coils tested to 300 lb pressure under water. Coils Product Cooling and Freezing Units Blower capacities from 2,000 to 30,000 cfm. Btu ratings to 225,000 at 10 deg TD. Available for above and below freezing duty. Patented defroster or glycol spray permits use to --40 F. Product Coolers Air Cooled Condensers Large heavy duty commerical and induBtri&l air cooled con densers in sizes up to 300 ton. Unique penthouse type design gains high capacity from limited space. Available with spe cially circuited coils and discharge dampers for head pres sure control- Air Cooled Condensers Patented Refrigeration Specialties Balance Loaders for obtaining compressor capacity control in infinite steps from 0 to 100 percent. Slug Eliminators for protecting compressors from breakage due to liquid slugging. In sizes to 100 ton. Balance Loader D  94 " Air CmulUindag . f2" WALTON LABORATORIES, INC. Irvington 11, New Jersey One of the world manufacturers of the largest diversified Line of humidifiers ALL MODELS TROUBLE-FREE WITH THE WALTON CENTRIFUGAL ATOMIZER For over 25 years this well balanced, whisper quiet at omizer has given positive humidification without pres sure devices, nozzles, or other complicated auxiliary equipment. _ PORTABLE ROOM HUMIDIFIERS are available in both table and automatically controlled console models with attractive wood-grained finishes. There are no heating coils or filters; no wet packs to become odorous or clogged. No fans that create an noying air movements in confined , areas. SPACE TYPE HUMIDIFIERS for commercial and industrial installations requiring controlled moisture conditions for manufacturing oper ations or storage of products. Need only small water supply line and electric connection through a control circuit. No costly ducts, compressors or drains are required. DUCT TYPE HUMIDIFIERS ' for commercial and residential installations. The right way to add needed moisture to any warm air-circulating system. Use water supply line and electric connection. Drain unnecessary. Produce vapor instantly without adding heat. WALTON'S CONSULTANTS' FILE offers you literature on all types of humidifiers with their many commercial, industrial and residential applications. Tell us your needs and covering technical information will be forwarded to you. _4?r Conditioning Cetri Sr**-** WORTHINGTON CORPORATION Air Conditioning and Refrigeration Division Section 12-14, Ampere Station, East Orange, N. J. 95 Condensers and Brine Coolers Packaged Liquid Chillers In air conditioning ... in refrigeration Worthington line means complete line Whatever the application ... in experienced staffs will plan for dustry , . . business . . . Worthing single unit or central system in ton offers you the trusted experience stallations, too. Architects, engi of over 70 years of leadership in the neers and contractors are cordially air conditioning and refrigeration invited to consult with us on any field. In new equipment, design, or - air conditioning or refrigeration the unmatched experience of problem. Offices or representatives Worthington engineering and ap plication staff, you are sure of precise recommendations tailored to your exact system needs. Further, a nation-wide organiza tion of distributors stands ready to in principal cities. Or, if you prefer, write to Worthington Corporation, Air Conditioning and Refrigera tion Division, Section 12-14, Ampere Station, East Orange, N. J. provide you with total sales and In Canada, Worthington (Canada) engineering service. Worthington's Ltd., Brantford, Ontario. WORTHINGTON  96 Air Conditioning Comi Snim YORK CORPORATION York, Pennsylvania Factory Branches and Distributor Engineering and Sales Offices throughout the World Subsidiary of Borg-Warner Corporation Air Conditioning and Refrigeration for maintaining proper temperature and/or humidity for industrial pro* cesses or comfort requirements. Installations of unit and central systems in a wide range of capacities and types for every design need. WATER COOLING SYSTEMS YORK HERMETIC TURBOPAK MULTI-STAGE TURBOS A packaged single stage hermetic centrifugal water cooling system for every air conditioning and process cooling purpose. Capacities range from 67 tons to 550 tons. Completely factory assembled and insulated with all controls factory mounted. Multi-stage centrifugal compressors for large comfort or industrial air-conditioning and refrigeration appli cations. Available over a wide range of capacities to 5,000 tons in a single unit. Suitable for motor or steam turbine drive. Pre-rotation vanes offer peak perfor mance at peak or partial loads. AIR CONDITIONING SYSTEMS YORK INDUCTION SYSTEMS Utilizes York Hermetic Turbopak or Packaged Water Chiller as a cooling source. Air, brought into building at one intake by fan, is filtered, dehumidified and . distributed in high pressure ducts throughout the building to individual units. Units in individual rooms ftlfin provide heat in winter by hooking into existing hot water system. Normal and high capacity units both available. YORK FAN COIL SYSTEM Cools in summer, heats in winter, uses Turbo or V/W compressor for cooling, building's hot water system for heating. Economical for buildings where space is at a premium. No large fan room required; units indi vidually operated. Floor, wall and ceiling models available. HEAT PUMPS Developed by York, compound compression air source heat pumps without supplementary heaters are economical and practical even in cold climates. Providing all- weather heating and cooling as needed for every air conditioning application, the heat pump eliminates the need for boilers, fuel storage and stacks. Air Conditioning . 97 ADDISON PRODUCTS COMPANY ADDISON, MICHIGAN Contract Manufacturers Central Air Conditioning--'Self-Contained or Split Systems Room Coolers Dehumidifiers Also Milk and Beverage Coolers--either Refrigeration Systems to Your Specifications CENTRAL AIR CONDITIONERS--AIR COOLED SPLIT SYSTEMS AIR COOLED CONDENSING UNIT--Sizes from 24,000 Btu/hour to 80,000 Btu/hour, single or 3 phase. Horizontal air flow. Completely weather-proofed for outdoor installation. Underwriters' approved. Equipped with oversized condensers for efficient, uninterrupted performance at high ambient temperatures. Compact design uses minimum space. Quiet opera tion--low velocity air flow through large openings. Completely accessible. Attractive appearance. Furnished for capillary feed or expansion valve applications. Optional refrigerant connections--including soldered, flared 3 hp Condensing Unit or improved quick connect couplings for use with refrigerant charged lines. "EB" Evaporator Blower Unit ' EVAPORATORS TO MATCH CONDENSING UNITS "EB" EVAPORATOR BLOWER--Quiet blower and smart appearance allow installation anywhere. Unit has adjustable four-way louvers. Return grille equipped with air filter. Fully accessible through removable panels. "UB" Universal Blower Unit "UB" UNIVERSAL BLOWER--Use with existing warm air system or separate ductwork. Blower assembly easily relocated to alternate positions --choice of vertical upward, horizontal or vertical downward discharge air connections. Fully accessible. "A" COILS--Designed for vertical air flow plenum installation. Uses the ductwork and blower of the heating system. Minimum resistance to air flow. Fully insulated. Coils slide into housing through removable front panel. "A" Coils, "H" Coils, Vertical Air Flow Horizontal Air Flow "H" COILS--Designed for horizontal air flow using ductwork and blower of the heating system. Install in plenum chamber or supply ductwork. Minimum air flow resistance. Insulated condensate drain pan. SELF-CONTAINED, CENTRAL AIR CONDITIONERS Available in 2 through 4 hp sizes. Designed and Underwriters' approved for outdoor installation. Equipped as factory assembled to meet FHA require ments. Compact designs allow installation through wall or in crawl space, attic or other limited access locations. Use with heating ductwork or as separate system. Capillary tube refrigerant feed system. Extra large cen trifugal blower delivers volumes of low velocity air over maximum surface coils for smooth, silent operation. Water Cooled systems also available. WINDOW AIR CONDITIONERS (Approved by the Underwriters' Laboratories) 2 hp Unit hp Portable Models from ^ to 2 hp. Compact design--quiet op eration. Automatic temperature control. Positive ex haust and ventilation. Designed for high temperature operation. Capillary tube refrigerant feed system. Easy access to all components. Variety of grilles and trim. SPECIAL SYSTEMS FOR MOBILE HOMES, DEHUMIDIFIERS, BEVERAGE AND MILK COOLERS.  98 HRYSLER AIRT EM P Dayton 1, Ohio Air Conditioning AIR CONDITIONING FOR EVERY NEED Engineered by Chrysler ROOM AIR CONDITIONER Easily installed in homes, offices or buildings. Chassis slides out if service is required. Thermostatically controlled, cools, filters, circulates, ventilates, exhausts and dehumidifies air. Capacities in 1,1^,2 and 2]/^ hp. Models designed for 7H and 12 amp, 115 and 230 volt operation, also for reverse cycle heating. CASEMENT WINDOW CONDITIONER Quickly installed from inside. No cutting or removing of glass; no outside projection. Window opens, closes, locks as before. Thermostatically con trolled,. cools, filters, circulates, ventilates, exhausts and dehumidifies air. Two-speed fan for super-quiet night cooling and exhaust features on Royal models. Capacities in %, and l-hp. ROOM AIR CONDITIONERS For year-round cooling and heating by connecting to central chilled and hot water systems. Designed for multi-room buldings, offices, and hotels. Three types--floor, wall, arid ceiling. Built-in controls permit operation to suit tenant. Two quiet centrifugal fans provide air circulation. PACKAGED AIR CONDITIONERS Completely self-contained, assembled, factory-tested, easily installed. Waterless and water cooled in 2 to 30-hp capacities. These Airtemp air con ditioners cool, dehumidify, filter, and circulate air. Free-air discharge or duct distribution. Heating coil for year-round air conditioning optional. Bon- derized steel cabinet occupies minimum floor space. Famous Airtemp sealed compressor--quiet, all moving parts balanced and bathed in oil for long life. Flexible mounting reduces vibration. 5-year warranty on entire refrigerant circuit. . LOW-COST HOME AIR CONDITIONING Compact waterless package installs easily in attic, dormer, or basement, either separately or connected to existing heating ducts, 2 and 3-hp capaci ties. Uses air and electricity only, no water piping needed. CENTRAL DUCT PACKAGED AIR CONDITIONERS Self-contained Central Air Conditioners in 25, 40,' 60, 75, and 100- ton capacities. Complete with Airtemp radial compressor and its exclusive features. Available with evaporative condenser, or for use with cooling tower. . AnlMMth EqaJpneal * asd C**Ua( h HRYSLER J AIRTEMP Dayton 1, Ohio 99 Air Conditioning Systems and Equipment Engineered by Chrysler GAS AND OIL-FIRED AUTOMATIC FURNACES Wide range to fit any application; Lo-Hi-Boy, Lo-Boy, and Counterflow automatic furnaces. Install in closet, attic or basement. Btu output from 65,000 to 250,000. Easy to add Airtemp cooling for year-round air' conditioning. HORIZONTAL GAS AND OIL FURNACES . For space-saving installation; in attic, under floor, or hung from ceiling Btu outputs from 64,000 to 168,000. Dual flue outlets. Draft diverter mounts on either side. Completely-automatic controls fully enclosed. WATERLESS CONDENSING UNIT Ideal for home or commercial use. Operates on air and electricity only--no water, no water piping, no cooling tower. Does not require winter shut-, down. Can be installed outride. Cabinet is weatherproof. In 2, 3, 5 and 7J^ hp sizes. . PACKAGED WATER CHILLERS Capacity from 25 to 250-hp, using Freon 22; and 3 to 75-hp, using Freon 12. Each package is factory-assembled, piped, pressure-tested, and furnished with refrigerant holding charge. RADIAL COMPRESSORS AND CONDENSING UNITS 10 to 125-hp capacities--heavy duty, for use with Freon. Specially de signed for air conditioning or refrigeration. Compressors have direct drive and have forced-fed lubrication. Automatic capacity-reduction. Light weight, economical to operate. * CENTRIFUGAL WATER CHILLER A complete refrigerating system with two-stage centrifugal compressor, evaporator, condenser, inter-connecting pipmg, purger, safety and operating controls. Wide application for summer air conditioning or process cooling. Capacities from 150 to 700 tons. Six compressor sizes, plus 64 evapor ator and condenser combinations, meet any requirement. X  100 Air Conditioning AMERICAN GAS ASSOCIATION ARKLA-SERVEL ...........now we're cooling Healing and * Cooling Srsidna American Gas Assn. Arkla-Servel with GAS 101 Specify Arkla-Servel Gas Air With their new Arkla-Servel Gas Absorptive Cooler, the La Grange Federal Savings and Loan Association keeps customers cool in summer with the same com pact system that keeps them warm in winter. Before installing Gas, a complete study was made of available air conditioning systems. The Arkla-Servel unit--the only 25-ton absorptive cooler--was chosen because it is compact, easy to install, and costs are low for installation, operation and maintenance. No specially trained operating or maintenance person nel are required. Conditioning and you specify years of trouble-free comfort . Only Gas gives these important advantages: high efficiency at all times--even during the light loads temperature control is constant modular adjustment of capacity (instant automatic adjustment to match actual cooling requirements) dependability of fuel service at all times Gas absorptive cooling can put your commercial and industrial clients' heating plant on a year around paying basis. It utilizes low pressure steam to cool water, has no moving parts to wear out, and provides quiet, economical operation. What's more, it's vibration-free. Take advantage of the consulting services provided by your Gas company. They have trained specialists who have been working with contractors and builders for years. They belong to your associations or affilia tions and are familiar with your problems. Check the facts about Gasand you'll see modern Gasatrconditioning out-performs all other fuels. American Gas Association.  102 Air Conditioning ARKLA AIR CONDITIONING CORPORATION Evansville 7, Indiana GENERAL. SALES OFFICE AND APPLICATIONS ENGINEERING DEPARTMENT SHANNON BUILDING. LITTLE ROCK, ARKANSAS ABSORPTION-TYPE 25 TON WA XES CRUXES--SERIES >050 Also available in multiples of GO, 7, and'100 tons. THE ARKLA-SERVEL SERIES 3000 RATED REFRIGERATION PERFORMANCE* - Water Chiller is a factory-sealed ab Tons Refrigeration...............................................................35.0 - sorption-type refrigeration unit with no Total Capacity. Btu per hour...................................... 300,000 moving parts, providing an economical Steam Input: source of chilled water for wide range of Bin per Hour, Me*..................................................... <50,000 comfort air conditioning and industrial Pounds per Hour, Max.....................................................46t process applications. It is readily adapt Clean dry steam at any prenure above 6 lb is suitable, able to multiple installations, with basic properly controlled. component of 25 tons. Water is the Chilled Water: refrigerant, lithium bromide, the' ab Inlet Temperature, "F..................................................... 60-0 sorbent, and steam, the source of Leaving Temperature, *F................................................<0.0 energy. Steam for operation is normally ' Water Quantity, gpm.......................................................60.0 obtained from a direct-connected gas Premure Drop, pei...... ......................................................3.0 boiler, but can come from practically any Condensing Water: source. The unit utilizes any steam GPM at 76* Inlet............................................................. 63 0 pressure from 6 to 15 psi. It operates Pressure Drop, pei........................................................... 13.0 under a vacuum, eliminating pressure * Refrigeration Capacity shown is based upon standard hazard; the chilled water circuit, how method of rating, specified by AmericanSecutfV fitfryw*- ever, is under pump pressure and not in* Engineer*; Inlet condensing water at 75*F and chilled . part of the vacuum system. A refrigera water entering at S0*F and leaving at <0*F. tion "package,'* the unit requires no field assembly, and is easily installed on physical data . any floor of a building. Vibration damp Net Weight, lb............................... !..................................3,800 ening is unnecessary. Automatic modu- j Shipping Weight, lb.......................................................... 3,325 lation of steam input is provided by 1 ' factory-installed steam controls. SERVICE CONNECTION SIZES Stam Inlet....................... . -.......................'.................** ^PS Steam Condeastts Drain Connection*: SSGCttohGeeDniaaieidUmmvneeAenIrVrntsWaeeilnternoagtVrtteaWDDartlarrv(DMaitepei.ianrv.T.l..ee(..r.F.r.a.C.t.e.e.p..om..r...n...a...V.n...l..e..ea......cl..C.v...t...ei.o..o.......nn........n..s......e.)........c..........t......i....o...........n...........s.........).....................l.....H..................*...............O..............DU..C.MW.2Sro**'IfIiIIPiPPpPgSSSSsr . ARKLA-SERVEL SUN VALLEY* GAS Air Conditioners THE ARKLA-SERVEL SUN VALLEY* All-Year Air Conditioner is a gas-fired, water-cooled absorption unit which automatically cools, dehumidifies, cleans and circulates the air at a controlled temperature in summer, and cleans and circulates the air at a predetermined temperature in winter. Principal parts of thin single-package year-round air con ditioner are an absorption combination refrigeration and heating unit, a filter section and a centrifugal blower... . In cooling cycle, a gas flame in the generator boils a water-lithium bromide solution, producing a water vapor which goes to the condenser. The condensed vapor flows into the single coil, over which air is blown. Heat is removed from the air and the vapor, through absorp tion, is returned to liquid ana flows by gravity to the generator for re-use. In heating, the water vapor by-passes the condenser and goes direct to the coil still hot. Then heat is taken from the vapor and the water by gravity returns to the generator . . . Circulation of the water, acting as refrigerant, and the lithium bromide, as absorbent, is achieved by differences in temperature and height of liquid columns, without moving parts. The unit operates under a high vacuum . . . available in two basic * models, the Model 500, 3^-ton and Model 750, 5-ton. * Trademark REFRIGERATION CAPACITY Gas Input, Full Capacity, Btuh Delivered Capacity, Btuh (Rated Cooling Capacity Baaed on Inlet Water 75*F., Inlet Air M deg db and 87 deg wb., 1400 CFM) 80.000 42,000 120,000 00,000 HEATING CAPACITY Cas input. Full Capacity, Btuh Capacity, Btuh 130.000 96.000 120,000 95.000 WEIGHT: Net (Approx.) Shipping (Approx.) 953 lbs 1,077 Lbe 1.163 lbe 1,303 lbe 120,000 60.000 180,000 144,000 Model 500 cjr,U bp, US V, y, I pb Motore shipped as standard. H hp, 330 V 00 1 pb Motors availableat ortra east. __ H hp, 115/3*0 V, t0 ey, I ph Motors available at *tra cost Model 750 MODEL 500 MODEL 750 H hp. 115/330 V, ey, 1 pb Motors shipped u standard. __ $4 bp, 115/330 V, 00 ey, i ph Motors available at mra eoetFor additional information, write Arkla Air Conditioning Corporation, Shannon Building, Little Rock, Arkansas Air Conditio: Heating. c**ting Units, * Caatrwi* and Filters KRITZER PRODUCTS A Division of PEERLESS OF AMERICA, INC. MAIN FACTORY AND OFFICES 5800 N. Pulaski Road, Chicago, 46, 111., U.S.A. 103 CBX COMBINEX WEATHER BEAM The Combinex Heating and Air Conditioning System (Patent Applied For) utilizes hot and chilled water and provides high-level discharge and lowlevel return for heating and high-level return and low-level discharge for air conditioning. Mounted in ceiling and discharges into plenum cham ber or conditioned space. Has control lever for changing direction of air flow. Capacity: % ton to 5 ton. Kritzer Low Voltage Control The Kritzer Unit control is com pletely factory wired and contains thermostat with thermometer, 3speed fan control, heating and cool ing cross-over switch and thermo stat adjustment for heating and cooling. Kritzer Live Air Grill Beautifully designed. Has broad flat hammered glass vanes which pro vide for full spread of discharge air. Three sizes: 14 in. x 6 in., 22 in. x 6 in. and 30 in. x 6 in. CXW CONCEAL-X (CEILING MOUNTED FAN COIL UNIT) Adaptable for new or old construction. Uses hot and chilled water providing compact, high capacity forced air heating and cooling installations. Capac ity: % ton to 5 ton. WCW CHILL-A-TRON LIQUID CHILLERS Completely packaged with water cooled condensers. Furnished with Kritzer patented Dimpled Tube exchanger surface. Easily installed. Complete hermetic unit with capacity range 2 ton to 22)4 tons. Two to 5 ton units furnished for single or 3 phase, 220 v current; units 7)4 to 22)4 tons furnished for 3 phase, 220 v current. Larger models to 350 tons also available. WRITE FOR LITERATURE containing complete specifications. Kritzer Electrostatic Filter and Grill Assembly furnished in sizes to suit systems. Grill is hinged and spring loaded and permits quick access to filter for removal and cleaning. DEHUMID-I-TRON A direct expansion refrigeration type dehumidifier with reheat. Capaci ties from )4 hp to 5 hp. Available in portable models or for permanent installations. Direct expansion, water and con denser coils; cooling towers; and air-cooled condensers available in many models and sizes.  104 Air Conditioning AMERICAN FOUNDRY and FURNACE COMPANY Bloomington, Illinois THE COMPLETE LINE IN WARM AIR HEATINGALL CAST IRON CONSTRUCTION FURNACES The New j/wA Optional Unit Construction. . . . The system that does not rely on excess outside air for temperature control . thus is inherently more economical "June-Aire" assemblies offer heating capacities from 222,000 to 3,420,000 btu per hour output and standard air flow from 2600 to 45,300 cfm. SYSTEM DESCRIPTION A completely pre-engineered unit com bining heating--ventilating--humidify ing, providing for convenient addition of summer cooling and dehumidifying. Made up of the following components: 1. "June-Aire" Furnace Unit designed to accommodate all burner models. 2. By-pass unit with clearances for cool ing coil. 3. Mixing damper unit. 4. Blower Unit. 5. Filter unit--Permanent or throw away filters. 6. Control panel, pre-wired. 7. Humidifier. ' AIR DISTRIBUTION CONTROL CENTER assures accurate, automatic room comfort Designed for dual duct systems providing heating, ventilating and air conditioning. Unit contains both balancing and mixing dampers--suitable for any type of temperature control system DRAFTLESS AIR DISTRIBUTION. QUIET OPERATION--No noisy fans or motors. . FINGERTIP AIR VOLUME ADJUSTMENT. . READY ACCESS TO DAMPERS AND OPERATOR. MINIMUM MAINTENANCE--Blowers, motors, filters, fresh sir intake and humidifier all at central location. Individual application of Air Distri bution Control Center with side grills. ' Air Distribution Control Center used with wing ducts. Air Distribution Control Center used with air handling wall book cases. FOR COMPLETE INFORMATION CONSULT SWEETS' ARCHITECTURAL FILE AMERICAN FOUNDRY AND FURNACE COMPANY . AIR HANDLING PRODUCTS CONSTRUCTION DETAILS Basic Designs DAMPERS VOLUME CONTROL . FACE AND BY PASS MIXING Parallel Blade F12 Opposed Blade F18 LOUVERS STATIONARY ADJUSTABLE EXTRUDED Comparable designs are available using extruded aluminum sections. A choice of frame and blade designs permits adapting extruded louvers to most air handling requirements. Weatherproof Stormproof F8A F9A. FIRE DAMPERS CLASS A Weatherproof WLD Automatic FLHV CLASS B SPECIFICATIONS Standard DAMPER SPECIFICATIONS Frames--2 x H z M is. or 3 x 1 in. x 14 ga Steel Channel- Maximum dimensions single section 48 in. wide x 96 in. high. Blades-- # 16 gauge steel dieformed. Width--Maximum 12 in- Minimum 4 in. Length--Maximum 48 in. Minimum 4 in. Shafts--H in- diameter steel rustproofed. Bearings--Oilite bronze Self-lubricating. Finish--Commercial steel painted alumi num or Galvanised steel not painted. Built to any dimension. Also available any material and any finish. LOUVER SPECIFICATIONS Constructed of commercial galvanized steel Frames ' Stationary--4 in. x If is. z 20 ga channel. Adjustable--4 in. x 1 in. x 14 ga box channel or 4 in. x in. x 14 ga angle. Blades Stationary--#20 ga. Dieformed with weatherlip both edges. Adjustable--#16 ga. Dieformed with weatherlip both edges. Built to any dimension. Also available any material and any finish. FIRE DAMPER SPECIFICATIONS All meet requirements of NBFU as sug gested in Pamphlet 90A. Class A dampers are approved type for ducts passing through fire walls or fire partitions. Class B are acceptable for installation in ducts at other than fire wall openings. Protecting links are UL approved. Built to fit opening size specified. ROTO-LINK SPECIAL PROCESS dampers which necessitate a SINGLE PURPOSE DESIGN APPLI CATION ENGINEERED TO MEET YOUR SPECIFIC NEED FOR . INDUSTRIAL PROCESS CONTROL FOR ANY DAMPER REQUIREMENT ALL LINKAGE INSIDE DUCT OUTSIDE AIR STREAM RECESSED MECHANISM PREVENTS DAMAGE OPERATING TORQUE LESS THAN 1 INCH POUND PER SQUARE FOOT OF DAMPER AREA . TUNNEL VENTILATION HIGH PRESSURE FAN OUTLET DUST COLLECTING SYSTEMS DRAFT CONTROL DESIGNED TO WITHSTAND UP TO 80 in. W. G. AIR PRESSURE. DYNE-AJRE Space Heatcra AFFCO Roof Hoods FOR COMPLETE INFORMATION CONSULT SWEETS' INDUSTRIAL CONSTRUCTION FILE  106 Air Condiiicnini i Hflyes Hayes Furnace Mfg. & Supply Co. l, CrJS FuP.SACfS I 3233 South LaCienega Blvd., Los Angeles 16, Calif. (Telephone Texas 0-3734) Contact Nearest Representative M. Blazer A Son, Paaaic, N. J. Luedecke Engineering Co., Austin, Texas R. E. Holcombe, Atlanta, Ga. McCombs Supply Co, Denver, Colo. Sinclair Heating Supplies, Ltd., Edmonton, Alberta, Canada McDonald Mfg. Co., Dubuque, Iowa Boyd Engineering Co., Albuquerque, New Mei,, and El Paso, Mechanical Equipment Co., Boise, Idaho Texas R. J. Clark Equip. Co., Clearwater, Fla. Dealers Supply Co., Atlanta, Ga. Reube O. Emery, Nashville, Tenn. FAD Distributors, Salt Lake City, Utah Frederick Co., Spokane, Wadi. General Engineering Co., Omaha, Nebr. J. C. Lewis Co, little Rock, Arkansas Noland A Co., Newport News, Va. Nunn Electric Co., Lubbock, Texas O'Connor-Oklahoma Co., Oklahoma City, Tulsa, Okla., and Wichita, Kansas ' Smith Steam Specialty Co., Kansas City, Mo. Central Service Co., Incn San Jose, Calif. Temp Control Corp., Portland, Oregon Valesco Inc., Visalia, Calif. DUCT FURNACES Heat exchanger constructed of Type 321 Stabilized Stainless Steel. Non-corrosive property of heat exchanger permits instai-: lation downstream of cooling coils, where codes permit, or washer. Heat exchanger will not corrode when subjected to continuous ventilation during the summer season. Designed for continuous blower operation for offices, theaters, schools, churches, and factories. Air throughput in either direction. Draft Hood and Vent Manifold reversible. 15 rises, 45,000 to 675,000 Btu per hr input in 45,000 Btu increments. A.GA. certi fied for all gases. MODEL SED-E Non-corrosive type 321 stainless steel heat exchanger. Permits installation downstream of cooling equipment, where codes permit, for continuous blower op eration. Air through-put in either direc tion. 45,000 to 675,000 Btu input. MODEL SED-S Same as SED-E except controls are at the ride, instead of at the end where ac cessibility requires. SED-S is available in sizes from 45,000 to 675,000 Btu input . in increments of 45,000 Btu. Both SED-E and SED-S can be used for industrial applications for drying. FORCED AIR FURNACE MODEL SEC Heat exchanger constructed of identical die fanned sections of type 321 stabilized stainless steel. Sections are seam and arc welded. One piece cast iron burners with drilled ports. Oversize double inlet blower. Long hour motor. Equipped with glass filters. Can furnish permanent filters at extra cost. Finished in baked silver gray. 6 sizes 70,000 to 245,000 Btu per hr input in 35,000 Btu increments. For natural, manufactured and L-P. gases. Can be used for 0 clearance. . ALL HAYES FURNACES ARE A.C.A. APPROVED AatMBMie Eqtiipe>< * Co Ffc-cd Hayes Furnace Mfg. & Supply Co. DUCT FURNACE MODEL SED-VF Tested sad approved as a DUCT FURNACE--Constructed of type 321 stabilised stainless steel. Equipped with air bypass. large cfm per Btu input. Vent in front of-' furnace. Made in B sizes from 70,000 to 280,000 Btu per hr input in increments of 35,000 Btu. For natural, manufactured and L-P. gases. 107 FORCED AIR SUSPENDED FURNACE, MODEL SES Equipped to install in a suspended duct system. Inlet and out let designed for sheet metal duct connection. UNIT HEATER MODEL SEU Used where room air is to be recirculated. Diffuser outlet with adjustable vertical and horizontal vanes. Both types of Sus pended'units are designed for factories, commercial and other large Btu requirements -- equipped with brackets for suspen sion, save floofspace. Double inlet forward curve blower. Con tinuous duty variable pitch drives; cast iron, raised port, pre cision machined burners. Made in sizes 80,000 to 480,000 Btu per hr input in 40,000 Btu increments. For natural, manufactured and LF. Gas. EJECTAIR Power Roof Ventilator by HAYES Centrifugal backwardly curved blower type ... the blower wheel cannot be overloaded regardless of length or curves in the duct or variation in design. It is belt driven to provide flexi bility. The ventilator is mounted on a built up curb on the roof. Special features include low profile with streamlined de sign and a corrosion resistant housing. The motor and fan bear ings are grease packed ball bearings and are out of the air stream. A manually operated safety cutoff switch is provided. DIMENSIONS Unit Size A B C D 1000 1200 1300 1600 1800 2000 2200 2400 2700 3000 3300 3600 4000 4400 4000 5403 24H 28 29 35K 39K 43 46M 49M -55X ' 66 75 85 90K OSH 108 .15H 17K 24^ 25H 27M 30 30>i 32H 34^ W 40 42H 45H 49 54 57K m 12 13M 16H 20 20 22M 25 28 31 33M 40M 40 44M 50 55 19M 21 21 24H 28 28 30K 33 36 39 41 48H 52 56 62 67 E ShapTwt. 16 130 16 137 16 180 16 275 16 300 16 325 16 350 16 500 16 590 16 630 16 700 16 795 16 875 16 1120 16 1500 16 1900  108 Air Conditioning buh mi c*Ub Unit* LARCO, INC. LINTERN PRODUCTS Route 20 East. Painesville, Ohio Crane Cab Conditioners Pulpit Conditioners Crane Cabs For steel, copper, and aluminum plants, forge shops, paper mills, glass plants, foundries, cement plants, incinerators ... wherever on-the-spot cooling is required... for temperature ranges up to 230F, CRANE AIRE-RECTIFIERS This Lintem air conditioning unit is of the split sys tem type allowing the condenser to be located high above the usual heat source on footwalk or trolley where the cab is so attached, as on soaking pit or strip per cranes. The condenser is connected to the cooling coil in the cab by two refrigerant lines, of high pressure hydraulic hose especially designed for "Freon" refrigerants, fitted with high quality "Hoze-Lok" fittings, eliminating soldered copper lines. ' Air Conditioning 109 LENNOX INDUSTRIES INC Marshalltown, Iowa Founded 189S. Plants located in Marshalltown and Des Moines, la.; Syracuse, N. Y.; Columbus, O.J Decatur, Ga.j Fort Worth; Los Angeles; Salt Lake City. In Canada: Toronto, Montreal, Calgary, Vancouver, Winnipeg LANDMARK* SERIES, HEATING AND AIR CONDITIONING, SEPARATE COMPONENTS OF MODULAR DESIGN TO ASSEMBLE INTO FULLY INTEGRATED UNITS One cabinet contains the air filter and blower; an other contains the heating section, whether it is gas or oil, ranging from 68,000 Btuh with gas, and from 91,000 Btuh to 378,000 Btuh of input with oil. Another cabi net contains the cooling coil, or the combination heat ing and cooling coil in the case of the Heat Pump. Heat pump and electric strip heating can. also be used with Landmark units. (Capacities can be increased by bank ing units.) Cooling and air handling capacities range from two tons through ten tons of refrigeration. Be cause of different capacities and different fuels for the ` heating section of each unit, the system designer can achieve perfect balance between heating and cooling in a building, whether it is residential or commercial, in the North or in the South. For- complete information on Landmark heating and air conditioning, or specialized assistance, phone, write, or wire Lennox Industries Inc., Marshalltown, Iowa. CAB UNITS This new Cab Unit is unique in that it can be easily mounted not only on ceiling or floor of crane cabs and pulpits, but also vertically against wall at any desired point between ceiling and floor. Compactly designed, fabricated of 11 gage steel, the unit includes an all copper evaporator or cooling coil, electric heat, dust and dirt filters, and activated carbon filter for elimination of odors and waste gases. A fea ture is the condensate fiber glass drip pan, light, easily handled, non-corrosive, and with large drain connec tion. CRANE CABS These full vision Lintem crane cabs are of our standard construction design requiring a minimum of engineer ing, permitting quick shipments, keeping costs down. They have a minimum of through-metal to reduce the cooling load. Provision is made for wiring controls and switches, as required. (Also furnished with new switches and controls, if desired.) Well designed, prop erly insulated, they centralize responsibility for proper, cooling performance. PULPIT AIRE-RECTIFIERS The Lintem Split System Aire-Rectifier allows for a' minimum of space consuming equipment within the pulpit, provides thoroughly cooled, dehumidified even air distribution throughout the pulpit without costly, space-using air. ducts. Condensers are located conveniently adjacent to the pulpit, connected to the cooling coils within the pulpit by high pressure hydraulic hose, especially designed for "Freon" refrigerants, and attached with "Hoze- Lok" fittings. A majority of the parts are interchange able with the Crane Cab Conditioners, minimizing the number of spare parts required in any mill. - Cooling Unit mounted on ceiling m LENNOX LANDMARK CFM PERFORMANCE TABLE Loadmerk CeotbissNeas Haettef Osfy (Up-Ha ar Dowo-Fto) 0 P ----- Hosting, Caafiag oad Hurt Pmap Up fie ar DosrnJTa 531 1 - zh~~ 1 STATIC PRESSURE EXTERNAL TO LANDMARK UNIT CM trM utr km'okp i*' 120 4MP .24* :w | tru kp mi okf toe 240 a 240 021 440 04S 474 044 SOS 07 (24 OK IBS 200 A) 124 044 440 04 sn 07 424 OO 540 JO MS m m 410 04 4(0 024 420 O* 4(0 .(0 410 .IK no US MS 440 02$ 410 .10 440 .12 (24 .11 410 JS 1000 400 M 424 .10 (40 .124 470 14 M .14$ 444 .144 ins 4(0 .12 OO .14 40$ .1* 420 Jl 4(4 J3 200 JU iee 440 J9 420 J4 470 JO n j* 714 .21 740 J$ 1400 444 Jl 4S0 .12 400 J4 740 .414 TOO M (K 04 oo 240 024 140 04 440 044 474 Ot 520 04 ___ ___ IBM no os in 04 420 0*4 400 .104 410 .12 '410 JSS 1200 W0 04 420 .10 470 .12 430 .14 470 .14 424 J? MOO 424 .12 4(4 .144 (SO .124 474 .14 40$ JI4 440 JS (too 400 .14 S Jl sn 'J* 4 J44 440 JS 700 JJ4 in 440 J4 cn , J24 44$ J2 420 JS 440. J7 740 02 400 J] 440 JO 444 .42 220 .444 740 -474 TK SB 420 .44 70S M 744 M 744 07 240 241 (20 04 400 2(0 OJ 200 120 04 too 170 04 no 414 02 1000 444 .<0 1200 444 .12 MOO 440 J2 1400 240 -24 too 04 410 O* 4S0 02 on .io 420 .1) 414 JO 700 Jl h> .44 444 04 410 07 100 OS 430 O* 424 .10 44$ .11 444 .IS sn .M 4*4 .14 424 .17 422 J4 700 J4 240 JS ' 774 J7 in .* (40 02 440 M M .10 440 -It 420 JS 440 .IS 7K J* (CO J4 *00 .44 41( (o 420 .12 440 .14 400 JS 710 J7 774 Jl (40 04 424 04 00 m 02 400 OS 4 on HO OM 440 .IK 4K .114 1000 US 04 4(0 002 4 .11 440 .IK STS .14 44$ J74 1200 440 .10 410 .124 474 .14 410 .IS 440 JO 444 JJ2 1400 41$ .142 STS .14 424 Jl 443 JS 440 J7 740 Jl 400 02 J14 700 .22 720 .322 744 J4 740 OO ttoo 440 .12 710 474 740 .<2 TOO .44 (00 07 MO 2IS zoao 720 .45 724 JO (20 SSS 440 04 040 OO 400 024 2200 OS JO MS M (SO .20 no ji *20 J44 440 Jl All CFM capacities listed here are extremely quiet, greater delivery can be achieved at a slight increase in sound level LENNOX INDUSTRIES INC. has more than 140 products to fill any heating and/or air conditioning need. ' Trademark, Patents Pending  no j. t# ASUBBllk UnDDuo /Itr Co/lOitJOrUrg Mewjn* nd Cooiia* The Majestic Co., Inc., Huntington, Ind. Majestic .250-400 Series Furnaces--Winter Air Conditioners in Two Sizes and Twelve Models for Oil or Gas, in Up, Down, or Horizontal-Flow Design Horizontal flow Downflow Upflow Model No. Bto Inpot* Blower CFM @ ye Tool stnt. Pres. Bto At Plcnatn rnng Size W-D-H W.A.4C.A. Pleaam Size Smoke CoUat Blower Motor U-25G-G D-250-P U-400-G :U-400*P D-250-G D-250-P D-400-G ` D-400-P H-250-G H-250-P H-400-G H-400-P 250,000 286,000 400,000 429,000 250,000 286,000 400,000 429,000 250,000 286,000' 400,000 429,000 3,000 3,000 4,000 4,000 3,000 3,000 4,000 4,000 3,000 3,000 4,000 4,000 200,000 220,000 320,000 335,000 200,000 220,000 320,000 335,000 200,000 220,000 320,000 335,000 32 X 49# X 91 32 X 49# X 91 32 X 55# X 91 32 X 55# X 91 32 X 49# X 91 32 X 49)4 X 91 32 X 55# X 91 32 X 55# X 91 32 X 49# X 67 32 X 49# X 67 32 X 55# X 67 32 X 55# X 67 * Oil Btu input based on 143,000 Btu per gallon. G--gas. P--oil. Gas units also available, same specifications, for LP gas. 24 X 39# 24 X 39# 24 X 45# 24 X 45# 24 X 39# 24 X 39# 24 X 45# 24 X 45# 24 X 39# 24 X 39# 24 X 45# 24 X 45# 8' 8' . 9' 9' 8' 8'. 9' 9' 8' 8* 9' 9' . . # HP X HP H BP H HP # HP # HP % HP H HP X HP X HP H HP X. HP Approx. Ship. Wl 820 855 975 1,100 820 855 975 1,100 715 750 900 1,000 Here are furnaces for large homes, office buildings, churches, schools, lodge buildings, factories--furnaces not just made bigger but expressly designed to deliver high bonnet capacity with the desired space and fuel economy. - From top to bottom, these superbly engineered units are built for just one function ... to extract every us able bit of heat from each unit of fuel and to deliver that heat quietly and efficiently through any type of modern forced-air system. , In the upflow models, tandem blowers are installed beneath the heat exchanger, while in the downflow models tandem blowers are mounted in a compart ment above the furnace, delivering volumes of air into a sub-floor plenum for modern perimeter distribution. A separate blower compartment is provided with hori zontal-flow- models so that the blower unit may be mounted on either side or rear of the furnace. Power gas burners with inputs of 250,000 and 400,000 Btu are furnished on the gas models. Oil burners are rated at 286,000 and 429,000 Btu input. Both oil and gas units utilize a pre-cast ceramic combustion cham ber, to shape and contain the flame for full efficiency. The heat exchanger is seam-welded of heavy steel plates and is surrounded by a four-tube secondary of unique design. Majestic also offers a full line of smaller furnaces and a complete series of system-matching summer air conditioners in a wide range of sizes and types. For full details and specifications, write The Majestic Co., Inc., Heating and Air Conditioning Division, Huntington, Indiana. Pennsylvania Furnace & Iron Company Warren, Pennsylvania 316 North Pine Street Series 10A Pennsylvania Forced Air Gas Furnace COMBUSTION CHAMBER: Extra large providing increased heating surface. Heavy gage metal insures long life. HEAT EXCHANGER: Die stamped corrugated sections furnish many flue ways from the combustion chamber and provide extra radiating sur faces. Corrugations create staggered flow of air across the flue ways. All seams in combustion chamber and heat exchanger are electric welded and BLOWER: Multiblade centrifugal type with double inlet and single bottom discharge equipped with special self-aligning bearings large oil reservoirs, rubber mounted for quiet operation, low speed motor, either split phase of capacitator type depending on -size. Overload protector, adjustable pulley, and V-belt drive FILTERS: Spun glass. Large area for efficient filtering over long periods. .BURNERS AND CONTROLS: Cast iron burners with raised ports accurately drilled for each size furnace and for the kind of gas to be burned. Venturi injection tubes prevent flash back. Operation is noiseless. Con - trols governed by room thermostat. Entirely auto matic. . CASING: Heavy and rigid. Doors provide easy access to blower and heating chamber. Controls enclosed. Finish hammertone steel blue enamel baked on. All joints tight. Furnace easily erected. This furnace was designed for those who want a high grade and efficient unit in the better class of . homes. Made in seven sizes. Input 75,000 to 225,000 Btu. A.G.A. approved. SERIES 11 ULTRA FURNACE This furnace is designed for gas or oil where standby . ,. , T. ., equipment is specified. It is made of 12 gage in three sizes: 75,000, 100,000, and 125,000 Btu. Can be fur- nished with gas burners and controls or with gun type oil burner. Efficient on either fuel. Has the- same blower and filter equipment as the 10A. (Furnace not shown). SERIES 55 PENNSYLVANIA GRAVITY FURNACE This line of gravity furnaces is made in three sizes with inputs of 75,000 to 125,000 Btu. The combustion chamber and radiators are cylindrical' The rectangular casing has corrugated inner lining providing efficient in sulation. The burner is single port type with venturi outlet and chrome flame spreader. Controls are automatic with special safety feature. Casing is finished in steel blue baked enamel. PENNSYLVANIA GAS CONVERSION BURNER X (Not Shown) This is a single port burner with automatic controls suitable for installation in coal or oil fired furnaces. Three sizes are available; 75,000 to 350,000 Btu input, .' PENNSYLVANIA MULTITUBE GAS CONVERSION BURNER (Not Shown) This burner is particularly designed for use in high pressure and tubular boilers in commercial and industrial installations. They are regularly installed through fire or ashpit doors in single or double units, Fully automatic controls are provided. Capacities range from 720,000 to 4,680,000 Btu.  112 Air Conditioning REFRIGERATION APPLIANCES, Inc. 909 West Lake Street, Chicago 7, Illinois Manufacturers of Freon, Ammonia & Flooded Ammonia Heat Transfer Equipment Since 1931 AIR COOLED CONDENSERS Quiet, remote type Multiple hanking in the field permits unlimited capacity ranges. Counter-flow refrigerant circuiting. Multi-circulating at no extra cost. Automatic Winter Control: Unique de sign eliminates low operating pressure and expansion valve problems due to failing temperatures. One valve controls pressure in condenser, one controls pres sure in receiver and a check valve stops liquid escape from receiver to condenser under all conditions. Rated Capacities: Single units 7.5 to 50 tons (belt drive, patented semi-auto matic adjustment), 1 to 7J> tons (direct drive). Certified nominal capacities based on 110F condensing temperature, 90F ambient. Air Conditioning . UTILITY FAN CORPORATION A Division of Utility Appliance Corp. 911 East 59th Street, Los Angeles 1. Calif. Manufacturers of heavy and standard duty blowers for heating, air con ditioning and ventilating installations. Producers of blowers and blower part for original equipment manufacturers. Built, tested and rated in ac cordance with ASHAE and AMCA codes. Sizos 12 in. to 73 in. Write for catalog data. 113 Heavy Duty Type "F" Design 29 Blowers are of the forward curved blade type for extraordinary efficiency - and quiet operation. Low tip speeds give lower noise levels. These blowers are available in sizes from 12 to 73 in., single and double width, Class I and Class II construction and all standard drive arrangements and discharge positions. Heavy Duty Type "FM Blower, SISW TRANSOM AIR CONDITIONERS Quiet-remote type for small fob* All aluminum construction. Insulated double drain pan. 3-speed control and thermal overload protection on motor. Rated Capacities: 9000 and 12,000 Btu/hr. . STANDARD AIR CONDITIONING COILS For new or old installation* Patented construction features. Positive fin spacing. Rated Capacities: 2 to 50 tons, 4 or 6 rows deep. . Special sizes: bi, % or Y* in. OD tubes with 3 to 12 fins/in. available. All copper and steel hot-dip galvanised after fabri cation coils available. COOLING OR HEATING UNITS Quiet-remote type Choice of coil arrangements for direct expansion, water, steam or combinations. - . Rated Capacities: 2 to 50 tons. Use with or without ducts for ceiling or floor. Insulated cabinets. Rust-resistant blowers. FURNACE AIR CONDITIONING COILS . low cost-bonnet type Converts old or new forced-air systems to summer cooling. Rated Capacities: 24,000 to 90,000 Btu/ hr. - . ' EVAPORATIVE CONDENSERS AND COOLING TOWERS Freon or ammonia for indoor* and out doors. . Rated Capacities: 5 to 100 tons. REQUEST NEW DETAILED BULLETINS Heavy Duty Type "8" Design 29 Blowers are of the backward inclined blade type for high efficiency at higher static pressures and non-overloading horse power characteristics. These blowers are available in sizes from 12 to 73 in., single and double width, Classes I, II, III and IV construction and all standard drive arrangements and discharge positions. . . Heavy Duty Type "B" Blower with Variable Inlet Vanes, DIDW Utility Sets for a wide variety of ventilation and-ex haust applications are available in sizes from 10 to 37 in. with Type "F" and Type "B" designs, single inlet arrangement Number 9 with rotatable housings for any desired discharge position. These Utility sets are completely self-contained units, ready to run with a weather-proof drive enclosure available for roof in stallation. . Utility Set Type "B" with Weather-Proof Drive Enclosure  114 tO IOT HEATER Air Conditioning CAMPBELL HEATING CO. 3121 Dean Ave., Des Moines 17, Iowa Telephone AMhetst 6-5169 OUTSTANDING PERFORMANCE You can be sure of outstanding performance at low cost, when you specify Campbell Warm Air Heaters. Fast heat delivery, positive contro) of temperature, humid' ity and ventilation--PLUS--low first cost, low installa tion cost, and low operating cost, all add up to cus tomer satisfaction. ENGINEERING SERVICE Our Engineering Department will be glad to help the consulting engineer or architect solve any heating, ven tilating or air conditioning problems or help with lay outs and specifications for any large building. Our Engineering Department consists of trained graduate engineers backed by 73 years of practical experience. HEATFR Heating Surface Normal rl BTUoe Qrttt CFM Unit No. Capacity BTU/Hr. 1 so Ft. Steel Thickness So. Ft. Area 140* primary |Secondary Heating Surface Sg. Ft Oischg. Tnmo. BLOWER! Wheel Width Inches Asswned RPM Motor External Static Size In. Water (HP1 HI BOY & HORIZONTAL UNIT HEATER -- OIL & GAS U223 U27S 11325 U4CO 225.000 775.000 325,000 84 121 121 U500 500.000 182 U600 600.000 182 700.000 244 U800 800.000 244 U950 950.000 U110C 1,100.000 334 U130C 1,300.000 455 UIS0C 1,500.000 455 14 5 I* 3 *" e 10 .. 10 &> 10 10 10 10 "T . 2 2700 3300 2700 3300 2750 3300 2850 3300 2850 3300 2850 3300 2750 T*m 13x12 3350 Twin 13x12 4900 T%in 14x14 7300 Twin 16x16 9800 T*in 18x18 11600 Twin 22x22 13500 Twin 22x22 16000 Turin 25x25 18500 Twin 25x25 704 635 600 515 462 375 390 K' H 1 i IK 2 3 3 3 5 LO BOY OIL & GAS FIRED FOR LARGE 231X300 275.000 340.000 400X300 450X100 500X100 2350 + 2200 - 2600 2750 Z 2700 2600 Tvi,,13x10 3300 T*inl3x10 4600 6600 18x16 22x22 9200 Twin 18x18 700 1 706 516 k 463 516 2 8000 SERIES OIL, GAS. STOKER OR HAND FIRED' 8032 6946 - 500,000 167 8060 G00.000 200 8074 700,000 233 8075 840,000 8100 960,000 320 8125 1,080400 360 8150 440 8175 1,440,000 480 6200 1400400 600 8250 2450,000 8300 2.700400 8350 3,150400 1050 1? 3000 3.2 5300 22 M\ K \| 4.6 22\i+ . |I 2r 7.5 11000 10.0 t2.5 15.0" 17300 17.5 3SK' 25.0 29500 30.0 35.0 44K' 49* 54K' MK' 677 ` 780 347 588 521 445 384 381 334 307 274 300 1.0 2 2 2 3 3 S 5 5 7K Gas Burner and built-in' Combustion Chamber and f Bum on 80% ttormil efficiency for oil end gw and 70% for coal- Add to*t loss for pick-up -load and 10% to 15% for duct raouten losses. Th for beet operating economy and life of the equipment. calculated CAMPBELL HEATING CO. 3121 Dean Ave., Des Moines 17, Iowa Telephone AMherst 6*5169 75 F HEATING GUARANTEE If the heating plant design is approved by our Engi neering Department or designed by a Registered Engi neer and the heater and blower are furnished by us and are in accordance with our ratings, we will guarantee the heating of all rooms to which warm air is delivered to 75F in the coldest and windiest weather. 10 YEAR DURABILITY GUARANTEE All Campbell Heaters installed as described above are guaranteed for 10 years against repairs from any cause, parts to be furnished free f.o.b. the factory. Motor, humidifier, automatic burner and controls and other parts not manufactured by us carry their manufactur ers' guarantee of one year against defects. All 2" Thick So. ft MAX FUEL RATE Oil 1000 LP Coa Largest Piece BTU Ou Lbi ifKD8 GPH Gw CFH OPH Hr, Oimensiod Wl lwrw 1 Ito. A DIMENSIONS B C DF H in. LW in. in. CHURCHES, SCHOOLS. COMMERCIAL & INDUSTRIAL BLDGS. 12.5 14.5 71 p -21.0 34.0 52.5 62.5 280 2.5 350 3.5' 3.6 500 5.0 5.4 750 7.5 875 7.2 1000 10.0 9.6 1375 13.8 11.6 1625 16 3 13.4 1875 lBfl 23x45x48 non 19 44 23x45x48 500 19 24x29x54 70(1 25 50 24x29x54 700 25 50 1000 30 ns 28x34x60 two 30 56 1400 36 74 33x40x78 1400 36 36x48x106 44 92 36x48x106 1900 44 92 50 110 42x54x114 2600 SO 110 12 14 18 20 24 26 29 30 9 72 66 22 66 10 24 72 24 72 48 48 54 54 12 at 84 60 28 84 60 14 31 99 78 33 99 78 16 36 106 96 35 106 96 18 42 126 114 18 42 126 114 73 23 29 29 34 34 40 40 48 48 54 54 1300 1700 2200 3250 4409 5800 1350 1750 2250 3350 4500 6000 RESIDENCES. SMALL CHURCHES. SCHOOLS. ETC. 9.0 11.0 16.5 16.5 16.5 22.0 25.0 ?S3 344 3.0 425 500 4.5 825 810 6.7 940 2.9 4.2 6.2 9.4 8"18x41x30 450 37 29x41x40 37 SI 8 29x50x48 600 36 38 29x50x48 680 38 34 29x50x46 750 36 34 34x60x48 900 40 36 38 44 10 34x60x54 1100 40 38H 48K 12 39x80x54 1250 60 40 50 61 87 87 74 91 76 97 72 104 41 50 so 60 60 80 1700 1900 2100 2400 2700 3200 3600 4000 2100 2500 2800 3200 3500 4100 4600 5000 FOR LARGE SCHOOLS. CHURCHES. ETC. 82.0 82.0 125.0 133.0 155.0 194.0 29Kx48x64 2954x48x84 2914*43x54 2954x43x54 28x72x76 28x72x76 28x72x76 28x72x76 28x72x76 35x90x95 ao 56 b-9 " 2-1C 2-12 M2 104 M4 104 M4 II M6 16 MG 28 H8 28 10000 12000 15000 18000 t For other *ir volume* and static pressures consult our Engineering Department. HORIZONTAL UNIT HEATER DOWN DRAFT--t/P ROW VMfT  116 Air Conditioning Mutiiil Hcaliag, Dbtet-Fbrd Ouun E. K. CAMPBELL COMPANY Manchester at 18th Kansas City 26, Mo. Sales and Service Offices in Principal Cities Heavy Duty Warm Air Furnaces Capacities to 8,000,000 btu Builders of Custom Heating'Equipment Since 1910 "Thermidaire" Design 10 "Thermidaire" Design 40 "Thermidaire" Design 41 "THERMIDAIRE" DESIGN 10 HEAVY DUTY FURN ACES--CUSTOM HEAVY DUTY EQUIPMENT FOR ENGINEERED APPLICATIONS. Typical Problems for which Design 10 Furnaces Offer an Excellent Solution: . Need for constant ventilation--To maintain freshness in any structure, particu larly where high occupancy loads occur, modulating face and by-pass zone ar rangements are used to obtain constant air circulation with "Thermidaire" Design 10 Heavy Duty Furnaces. Need for air conditioning--Since most modem structures have either present cooling requirements, or will have at some future date, the large air capacities needed ana the basic distribution system required are readily available in the structure using "Thennidaire" Design 10 Heavy Duty Furnaces. Need for very large capacity equipment--Where large loads exist, the high output capacity available from single units simplifies the solution. "Thermidaire" Design 10 Heavy Duty Furnaces available in standard sizes with output to 8,000,000 Btuh and 145,000 dm, larger on special request. Need to meet special design requirements--For balancing Btuh vs. cfm component sizing, separate sizing of furnace and blower elements permits "Thermidaire" De sign 10 Heavy Duty Furnaces to meet special requirements for very high or low air volumes, or temperature rises, and to handle unusual jobs, process needs, or exceptional buildings. Need for flexible or special equipment arrangements--Where building di mensions limit outlet or inlet duct arrangements, location of firing front or position of blower relative to air conditioning or furnace components "Thennidaire" Design 10 Heavy Duty Furnaces are excellent due to the extreme flexibility possible in arranging equipment. Need for foil convertibility to any fuel--Where dual fuel equipment is required, or in event of future changes in fuel requirements, (including gas, L. P., oil light or heavy, and solid fuels), "Thermidaire" Design 10 Heavy Duty Furnaces offer com plete protection since any of these fuels can be efficiently burned. Need for extra quality equipment--"Thennidaire" Design 10 Heavy Duty Fur . naces are the highest quality equipment available, designed for continuous duty and long life on tough jobs ana large loads. ' Only Heavy Duty blower equipment is used. Only highest grade burner and control equipment used. Extra Heavy welded steel construction throughout. Baked enamel exterior finish. Fiberglas insulated casing. Low Internal resistance to flue gases. Operating efficiencies up to 84 percent with resultant fuel economy. Counter-Flow heat transfer. Positive pressure or Drive through principle. . Need for special services-- Our half-century of application experience in the specialized field of heavy duty warm air heating is available to assist in arriving at the proper solution to your problem. We recognize that satisfactory solution of the Users problem is the end objective and we back our equipment with competent field service to accomplish this. "THERMIDAIRE" DESIGN 40 HEAVY DUTY FURNACES Standard heavy doty equipment for general heating applications--Available from 250,000 to 2,000.000 Btuh output'in vertical, horizontal, and inverted models--avail able for gas, oil or combinations. Provides convenient compactness, high efficiency, simple installation. Blower, burner, ID fan and controls, mounted, wired and fire tested. Normally shipped assembled. ' "THERMIDAIRE" DESIGN 41 HEAVY DUTY FURNACES Standard heavy duty equipment for engineered applications--designed for use; with face and lay-pass, constant ventilation, or air conditioning--requires separate" blower--has built in by-pass section--available in same models and fuels as Design -40, in sizes from 250,000 to 3,000,000 Btuh output. Provides convenient compactness, high efficiency, simple installation. Burner, controls and ID fan, mounted, wired and fire tested. Normally shipped assembled. OTHER DESIGNS AND SPECIAL EQUIPMENT AVAILABLE ON REQUEST Air Conditioning Di.Firj aatr* 117 CHICAGO STEEL FURNACE CO. Home Office & Plant 9326 S. Anthony Ave., Chicago 17, Illinois Engineering Sales Offices from Coast to Coast TUBE AND TRANSFER BOX ACCESS MATE REgent 1-0280 TWO-PASS ALUMINIZED STEEL EXCHANGE Up Flow and Counter Flow Horizontal Furnaces and Duct Heaters 120,000 to 2,500,000 Btu Output Single and Dual Fuel; Oil and/or Gas Horizontal Furnace Duct Heater 442 S.S, RIBBED TEAK OROP CONSTRUCTION, 2-PASS COMBUSTION CHAMBER FOR STRENGTH AND EFFICIENCY Stainless Steel Unit WE1DEO 12-GAUGE FRAME STRUCTURE Chicago Steel Furnace Co. announces the production of a new line of steel furnaces made of stronger 442 Stainless in capacities to 2H million Btu's in all popular designs. Chicago's 442 Stainless line supplements the refractory lined series still available. All models available with either duct flange connections or (optional) with 4-way adjustable diffuser heads and screened intakes. Cuts and features here shown pertain to our stainless steel series of furnaces only. Firing equipment, all fuels, UL and A.G.A. inspected and approved. STAINLESS STEEL SERIES*  118 Air Conditioning Indastrial Heating, Dind-fM Brmn DRAVO CORPORATION Neville Island Pittsburgh 30, Penna. Atlanta, Baltimore, Boston, Chicago, Cincinnati, Cleveland, Detroit, Dallas, Indianapolis, New York, Philadelphia, Pittsburgh, San Francisco, St. Louis Sales Representatives in Principal Cities DRAVO Counter COMMERCIAL SPACE HEATERS . 350,000 to 2,000,000 Btu/hr output PYROJET BURNER--Designed and built by Dravo exclusively for the Commer cial heater, the induced draft Pyrojet bums gas, light oil, heavy No. 5 oil or combina tion gas/light oil. Combination firing has manual or automatic switchover control. STAINLESS STEEL COMBUSTION CHAMBER--Designed for maximum Same travel and efficient wiping action of air stream for efficient heat transfer. Ruggedly built for long, trouble-free service. SAFETY TESTED--Approved by A.GA. and listed by Underwriters Laboratories, Inc., Dravo Safety Control Circuit is accepted by Factory Mutual Engineering Divi sion and Factory Insurance Association. . 10-YEAR GUARANTEE--All standard model Commercial Heaters cany a fully bonded 10-year guarantee on all parts in direct contact with flame or flue gases. Drava Caatanareid Space Heater*, in addhlan t Mwltrt hc*ila(, art eerily adapted la kcit earlag and pracc** diytaf, tempering ar replaaa. meat air, duet finuca, and far caaunertime nullitlan. DRAVO INDUSTRIAL SPACE HEATERS ' 400,000 to 2,000,000 Btu/hr output ECONOMICAL--Package type burner for gas, fight oil. No. 4 oil or automatic switchover from gas to light oil. Easy to service, this is a rugged mill-type heater which will provide long-time, low-cost, efficient heating in most types of installations. STAINLESS STEEL COMBUSTION CHAMBER--Full floating stainless steel combustion chamber, designed for four-pass flame travel to assure maximum heat transfer. Economiser tubes whirlcool the hot gases for added efficiency. APPROVALS--Burner and control components approved by Underwriters Labora tories, Inc^ and by A.QA. where applicable. . 10-YEAR GUARANTEE--All standard model Industrial Heaters cany a fully bonded 10-year guarantee on all parts in direct contact with flame or flue gases. TKe Dravo fadoatHoI Spaeo Heater b a rafted . till-type economy beater. Eaay terrierability aad loaf life make tbla tbe mod oeoaomleal bay far maay Innallatlena. la readily adaptable ta promt area, for tempering of replaaemrat air aad many etber applltattaa*. DRAVO J^aw/b SPACE HEATERS 200,000 to 250,000 Btu/hr. output POWER AND FUEL--Heater operates on 120 volt 60 cycle single-phase current. 440/220 volt three-phase operation can be supplied if desired. Bums fight oil or gas. FAST TRANSFER OF HEAT--Stain less steel combustion chamber allows faster heat transfer and guarantees longer heater life and sustained efficiency. Equipped with UL approved gun-type oil burner or A.GA. approved gas burner. FLOATING COMBUSTION CHAM BER--Supporting straps hold stainless steel chamber in place for inverted or horizontal mounting. HEAT ANY DIRECTION--Warms areas up to 3600 sq ft. Directional nozzle can be rotated 360s heating any desired, location, high velocity discharge assures adequate distribution up to 90 ft from the unit without the use of ductwork. DRAVO Gas Fired Suspended Unit Heaters available for 40,000 to 104,000 Btu/hr applications. DRAVO Paraflo Air Ci ladoetrial Beating, Dlaect-FIrad iditiontng uuit ?<=*!* Uan JACKSON & CHURCH Division of York-Shipley, Inc., York, Pa. 119 These new units incorporate a true counter-flow design. Heat ing surfaces are arranged for highly efficient heat transfer, allowing minimum pressure drop through the heater. Flexible application as they can be installed upright, laid on their side, or inverted. Fully automatic controls, installed and wired for complete programming sequences. For No. 2 oil, natural, mixed, manufactured, L. P. gases or combination. - JC-40 jc-so JC-75 JC-100 JC-IK JC-160 JC-175 JC-500 42)0 5450 8170 1260 1600 16330 irso ><050 818D0 J-C OIL-FIRED SUSPENDED FURNACES Economical and trouble-free operation of Jackson & Church Suspended Oil-Fired Furnaces is assured. Compactly designed with features that architects, engineers, and builders prefer. Units have stainless steel combustion chamber with over-size air passages for increased heating surfaces. Cabinets are heavygage, rust-resistant steel. Model Nix OL-US-810 0OLL--3158008-2S3li OL-350-S38 OL-560-S39 OL-M0-S45 OH250-S80 OL-126O-S100 OL-3aM2Fl7* 10000 12600 2230 36)4 44 6254 6254 2254 Firing with light oil and/or natural gas ,in ail capacities. Architects and engineers will find in this line the latest engi neering advances in furnaces designed for heavy duty require ments. J-C GAS-FIRED FURNACES Each size comes in three different styles--as a horizontal furnace (GS) for suspended or floor mounting, as a blower-type unit heater (GU) for suspended or floor mounting, and as a duct furnace (GDF) for quick adaptation to year-round air conditioning. All A.GA. approved. lOOLBto 160 160 00-24 ODF-24 GA-230-CF17I 192 193 193 234 - 234 224 17S t CogaUrfluv Model. JJM 2000 2125 2430 2560 2830 2990 H In. 34)4 m 3454 3454 2454 34)4 >454 3454 72H W In. 28M 26H r L. Is. 66*4 6854 <S 46H  120 JOHNSON HEATER CORP. 1 Winnisimmet St., Chelsea, Mass. Air Conditioning DESIGNERS MANUFACTURERS JOHNSON MODEL FA FACTORY ASSEMBLED "FYRE TUBE" HEATING UNITS Engineered and designed for all types of commercial and industrial direct-fired heating applications, with or without duct work. ' Single heater output capacities from 400,000 to 4,000,000 Btu/hr. Fired by light or heavy oil, gas or combination of both. Furnished as standard with UL and FM accepted burner and control systems, chrome nickel stainless steel combustion chamber, large capacity circulating blowers and separate motor driven induced-draft fan. - Cutaway view of Johnson Model FA Unit (Type VP). Note the rugged compact construction with accessible service and maintenance features. . TYPE VN Vertical floor model with adjustable discharge heads. TYPE HP Horizontal suspended type for duct connections. TYPE HN - Horizontal suspended type with discharge nozzles. TYPE VP Vertical floor mounted units for duct installations. TYPE VPO Using separate outside blower for combination beating, cooling or ventilating appications. Also furnished for horizontal mounting TYPE HPO. TYPE ITS' Inverted type using adjustable discharge.nozzles. Furnished without nozzles for duct installations TYPE IP. ID4ir<ekc>wt-UFi1ndHcHaU<Hasc,r JOHNSON HEATER CORP. I Winnisinunet St., Chelsea, Mass. 121 DESIGNERS MANUFACTURERS MODEL JA HEAVY DUTY COMMERCIAL AND INDUSTRIAL "AIRE TUBE" HEATERS 15 Sizes--Output Capacities from 400,000 to 5,000,000 Btu/hr. DirectFired by heavy or light oil, gas or a combination of both fuels "AIR ROTATION" SPACE HEATING One, free standing, Model JA "AIRE TUBE" Heater en uniformly heat in excess of 1,500,000 cu ft of open building space without duct work, noticeable drafts or the beed to spot, throw or direct the heated air. .. This is accomplished with our "AIR ROTATION" system of space heating in com bination with our special heater design. Large volumes of the cooler and denser, low-level air from the building are rotated through the heater. This air is then heated to a low temperature and discharged at a low velocity from the heater outlets baek into the area to be heated- DUCT DISTRIBUTION SYSTEM JA "AIRE TUBE" Heaters with low internal resistance are excellent for use with all types of duct distribution systems. HEAVY OIL FIRING JA Heaters are especially designed for firing with the low cost #5 or #6 fuel oils in the larger sizes. . JA Heaters have approximately 90 percent-direct heating surface with multiple hanks of practically self cleaning, air-heating tubes located over the lire. MODEL JAS Horizontal Suspended "AIRE TUBE" Heating Units. 17 ` Sizes Output Capacities from 112,000 to 1,000,000 Btu/hr. Factory assembled Multiple air tube design Practically self cleaning Low draft requirements Chrome nickel steel combustion chamber Available as duct heaters without blower section in range of sizes listed above. - Direct-fired by light oil, gas or a combination of both fuels SMALL MODEL JA MODEL HB For beating small commercial-industrial and domestic buildings Designed for use as a space heater or with duct distribution systems (EXTENDED CASING TYPE SHOWN) Nine sizes output capacities from 112,000-350,000 Btu/hr. Fired by light oil, gas or a combination of both. (SPACE HEATER SHOWN) Nine sizes output capacities from 112,000-350,000 Btu/hr. Fired by light oil, gas or a combination of both.  122 Air Conditioning KSjSLfElE. LENNOX Industries Inc. Manufacturers of Warm Air Beating Equipment 1701 EAST EUCLID, DES MOINES 4, IOWA Representatives In All Principal Cities SPACE HEATING, DRYING. I MAKE-UP AIR AND OVEN APPLICATIONS "OG" SERIES HEAVY DUTY HEATERS Specifications--Gas, oil or combination burners with manual or auto matic fuel selection. 300,000 to 500,000 Btuh output. Control system is packaged, factory-tested. Applications--Can be used as a central furnace with ducts or as a unit heater. Installations may be horizontal, vertical, suspended or floor mounted. Listed by V. L. and complies with factory mutual insurance re quirements. Blower Section--Huge air volume delivered quietly from dynamically balanced blowers. Up to 2 in. external static pressure. Blower section can be used for air conditioning, will handle up to 30 tons of cooling. A wide choice of blower motors and drives satisfies all air volume requirements. Construction--Compact, rugged, with 16 gage stainless steel heat ex changer; secondary heat surface of aluminieed steel to resist corrosion. Exceptional expansion joint allows unit to "breathe." Burner enclosed in sound proof compartment. Heater uses adjustable discharge nozzles or ducts. (Write for Bulletin OG-581-M10.) ' "AT" SERIES HEAVY DUTY HEATERS Specifications--Gas, oil or combination burners with manual or auto matic fuel selection. 750,000 to 2,000,000 Btuh output. One master control ler eliminates non-standard, hard-to-replace system components. Design Features--Special 4-pass counter flow design without the use of internal baffles gets the most heat from the flame. Boiler tubes, equipped with high-velocity retarders, and double casing, with metal radiation shield, contribute to operating efficiency of 80 percent or better, while hold ing casing heat loss to minimum. Blower Section--Quiet, large-capacity blowers may be removed for re mote applications if desired. Applications--"AT" heaters offer wide variety of uses and applications in department stores, warehouses, manufacturing plants, process indus tries, truck terminals, apartment houses, office buildings. Units can be floor mounted in upright, inverted, or horizontal positions; suspended ver tically or horizontally from ceiling (service platform optional). (Write for Bulletin LDM1-G-5-58.) GAS DUCT HEATERS Wide range of uses: Hotels, motels, stores, schools, service stations, factories. Btuh input ratings per unit from 120,000 to 420,000. Depth is never more than 49 in. including diverter. . Dual limit controls provide complete protection for air travel in either direc tion. Can be fired .with all types of gase ous fuels. ` Provides positive rone control with pre cise thermostatic action. Can be used . alone or added to an existing system. (Writs for Bulletin GSD-681-M8.) GAS UNIT HEATERS Btuh input ratings per unit from 80,000 to 250,000. Dual vertical and horizontal louvers diffuse warm air evenly over a wide area. Quick, easy installation made possible by easily balanced hangers. Motor has overload protection, is cushion mounted and totally enclosed. Attractive cabinet design allows "exposed" instal lations. Controls include automatic pilot with 100 percent safety shut-off. * Heat exchanger: Aluminized steel, with 18 gage tubes and 16 gage headers(Write for Bulletin LDMl-G-6-68.) - Atr CondUi U*limf, *6 DIrcet-Fired Hesters MAMMOTH FURNACE COMPANY 6425 CAMBRIDGE STREET MINNEAPOLIS 26, MINNESOTA 123 Commercial-ft DJRECT-FfRED SPACE HEATERS Commercial-Aire Direct-Fired Space Heaters have a high fuel-to-heat conversion efficiency. They are ruggedly built for quiet, vibrationless operation. All controls, wiring, and moving parts are accessible for service. Among the many desirable features are the central control cabinet, retractable burner tray, MH-Electronic flame control, pre-ignition draft purge timing and draft sensing, and vortex cooled motor shaft to blower wheel. A variety of controls, power supplies and burners by reputable manu facturers may be specified and integrated. Write for Bulletin C-357. SAFETY TESTED and approved by A.G.A. Labora tories and Listed by Underwriters' Laboratories, Inc. Commercial-Aire safety control circuit is ac cepted by Factory Mutual Engineering Division and Factory Insurance Ass'n. Control circuit wiring meets J.I.C. Requirements. Modal 300 400 550 700 300 1750 MODEL **F" Floor mount with discharge heads lor Industrial piants.foundries, etc. MODEL 'H" L Horizontally sus pended- unit (or use where floor space It unavail able. MODEL "FO" For duct distribu tion. For church es, schools, au ditoriums, etc. Btu Output 300,000 400,000 S50.000 700,000 300.000 1,000.000 1.250.000 1.500.000 1.750.000 3.000,000 Sq.ft. Htg. Surface E.D.T. 15S.3 135.3 183.6 183.6 276.8 276.6 431.0 431.0 574.1 574.1 Cfm <d y.` EXT. S.P. 85 RISE 4.000 5,500 7.000 8.700 10,000 13,000 16,000 19,000 23,000 56.000 Blower OIOW 14*-twln 14*-twin 14'-triple l4*-triple J6*-triple 16*-trlpie 18*-trlple ir-triple ZIMrlple 21"-triple SPECIFICATIONS Motor Approx. hp Fan rpm % 1A 2 3 5 5 754 754 10 575 640 750 820 710 TOO 755 830 680 740 Max. Firing Rate Oil Gas gph cfh 3.0 4.0 5-0 7.0 7.5 9.S 11.5 14.0 16.5 18.5 375 500 688 875 1.000 1.250 1.S63 1,875 2,188 2,500 Length Height Width 60* 80* 32* 60* 80* 32* 30* 80* 32* 80* 80* 32* 80* 83* 48" 80* 83* 48* 100* 96* 54* 100* 96* 54* 120* 96* 60* 120* 86* 60* Plenum Opening 18x60 18x60 18x80 18x80 22x80 22x80 26x100 26x100 30x120 30xt20 MODEL "IT Suspended In verted unit for make-up air ap plications in plants, foun dries, etc. Meeh. Approx. Exhaust Shipping. Discharge Weight rdia. 8*dia. 8*dla. 8*dla. I0*dia. 10*dia. 10*dia. 10*dla. 12*dta. 12*dia. 1,590 1,690 1,950 2,150 2,775 2,850 3,850 4,010 4,750 4,910 COM PACTO HORIZONTAL SUSPENDED HEATERS Require no floor space. Easily suspended from rafters or installed in loft or attic with or without ducts. Available as complete wired package ready for fuel line hook-up or with burner and controls unwired and unassembled. Has rugged 10 and 11 gauge welded plate steel heat exchanger with in ternal stainless steel combustion chamber for trouble-free performance. Oil or gas fired. Write for Bulletin 57S-1. MODEL 165 225 260 300 350 400 450 B.T.U. INPUT 232.000 260.000 326,000 375,000 450,000 500,000 560,000 B.T.U. OUTPUT 185,000 225.000 260,000 300,000 350,000 400,000 450.000 SO. FT.. HEATING SURFACE 55.4 55.4 78.2 78.2 130.3 1303 130.3 C.F.M. @ %* S.P. 70 AIR 2130 2580 3000 3450 4030 4600 5200 F IC AT IONS C.F.M. G W S.P. 85 RISE MOTOR BLOWER H.P. SIZE 2460 A 14' 2380 A 14* 3465 y. 16* 3985 % 16* 4655 i 18* 5313 i>4 18* 6000 1J4 18* APPROX. BLOWER R.P.M. 509 539 525 565 575 GOO 650 FIRING RATES OIL G.P.H. GAS C.F.H. 1.75 2.00 2.50 2.75 3.25 3.50 4.00 232 280 326 375 450 500 5G0 APPROX. SHIPPING WEIGHT 695 72S 890 935 1010 1040 1055  124 Air Conditioning . National Heater Company, Inc. 2475 Doswell Avenue St. Paul 4, Minnesota . Sales representatives in principal cities in U. S- and Canada ' SPACE HEATERS MODEL H--Standard upright (floor set) model. Also MODEL D--without discharge heads for duct installa tions. TO Series 6 models--66 sizes! Gas, oil or gas & oil fired! Stainless steel combustion chamber! 80 percent operating efficiency! Basic models UL or A.GA. approved! - Low initial cost! . Easy, quick installation! Low operating cost! Minimum maintenance! Floor and suspended models! No full time operator required! Completely automatic--thermostatically operated! Factory flame-tested! - A complete "packaged" heater requiring only fuel line, power and stack hook-up! WRITE FOR 1959 CATALOG MODEL S--For Churches, Schools. Public Buildings and institutions. MODEL R--Inverted sus pended unit. For make up air applications. MODEL P--Selfcontained portable unit. - MODEL C--Horizontally suspended unit. Ideal where floor space is lim ited. Heater Number Btu* Output Standard! CFM Blower* DWDI fu Motor HP Supply Faa RPM Plea am Opening Approx. Shipping Weifat TD-50 TD-100 TD-175 TD-200 "TD-250 TD-300 TD-350 400,000 500,000 550,000 650,000 750,000 800,000 850,000 1,000,000 1,250,000 1,500,000 1,750,000 2,000,000 2,500,000 3,000,000 3,500,000 5,400 6,600 7,100 7,600 8,800 9,600 10,500 12,500 15,300 19,400 22,000 26,000 32,000 38,000 46,000* 15'-Twio 15'-Twin 15' -Twin 16'-Twin 16'-Twin 16'-Twin 18'-Twin 18'-Twin 21'-Twm 21'-Twin 21'-Triple 21'-Triple 24'-Triple 24'-Triple 24'-Triple . 1 Ik 2 2 2 3 3 5 5 7* 7f 10 10 15 20 560 595 670 695 720 590 640 560 590 630 670 18 X 60 18 x60 18 x 60 18 x SO 18 x 80 18x80 18 x 80. 24 x 100 24 x 100 30 x 120 30 x 160 1400 1500 1550 1750 1900 2400 3200 3450 4150 6630 6720 Tested and rated in accordance with the code adopted in 1956 by ASHAE for Heavy Duty Furnaces A Direct Fired Unit Hest- i. t Higher CFM ratings available on application. Specification data subject to change without notice. Esdutrui Beating. , National Heater Co., Inc. Direct-FiraS Beaten 3 125 U SERIES HI-BOY and COUNTER-FLO MODELS WARM / AIR SPACE HEATERS U Series HI-BOY and COUNTERFU) models. > Research-designed for compactness plus efficiency are prime requirements. The HI-BOY upright units can be equipped with adjustable discharge heads or ar ranged for duct connections. COUNTER-FLO models for under floor heat distribution systems or inverted ceiling suspension. Five sizes--175,000 to 350,000 Btu output capacity for either gas or oil firing. . T-F SERIES SUSPENDED UNITS T-F Series suspended units. Heavy duty suspended units engineered for industrial and commercial heating applications where floor space is at a premium. Rugged, compact, easy to install--with four-way adjustable discharge head or for convenient integration into a duct distribution system. Duct heaters available in identi cal Btu capacities. Special stainless steel and alumi nized steel can be furnished for high temperature ap plications and corrosive conditions. Nine sizes-- 180,000 to 550,000 Btu output capacities--gas or oil fired. T-F SERIES SUSPENDED UNITS Fan CFM Capacity AvaiLSP Faa Motor HP Oimaaaiau Jq L .W H TF-18 TF-20 TF-23 TF-25 TF-30 TF-35 TF-40 TF-45 TF-55 180,000 2,050 200,000 2,300 230.000 ' ' 2,800 250.000 3,000 . 300,000 3,700 350.000 4,500 400.000 , 5,200 450.000 5,800 550.000 6,400 H H H x H % h % H H H H H H l ix 2 73 31 28 73 31 28 77 36 32 77 36 32 77 36 32 92 48 42 92 48 42 99 48 48 99 48 48 1850 * Tested &od rated i Heaters. accordance with the code adopted in 1955 by ASHAE for Heavy Duty Furnaces and Direct Fired Unit U SERIES--HI-BOY and COUNTER-FLO MODELS - Model U:175 Reiters*** Output BTU/Hr* Fas CFM ' Capacity Fan Motor HP Faa RPM Dimensioa* in Lw SMppini Weight H 175,000 200,000 250,000 300,000 350,000 2,000 2,300 3,000 3,700 4,400 y*. H X H 1 520 38 560 38 35 440 42 543 42 500 42 35 83 1,060 rated in accordance with the code adopted in 1955 by ASHAE for Heavy Duty Furnaces and Direct Fired Unit Spedficatioo Data Subject .to change without Notice. WRITE FOR 1959 CATALOG  126 Air Conditioning iMMtui iiaiun Dull Heater* THERMOBLOC DIVISION.PRAT-DANIEL CORP. 2 Meadow Street, South Norwalk, Conn. Canadian Affiliate: Canadian Wanson Combustion Equipment Ltd., Montreal PANELBLOC Air Conditioning Ittiaitriil BtMlnf, Olnti'l'M Hcucn %127 TJERNLUND MANUFACTURING COMPANY 2140 KASOTA AVENUE - ST. PAUL 14, MINNESOTA Manufacturers of Industrial and Commercial Warm Air Heating Equipment, Oil and Gas Burners, Blowers and Draft Inducers CR-63 (62^00 Btu Input) CR-125 (125^00 Btu Input) PANELBLOC INFRA-RED RADIANT HEATERS BRING THE SUN INDOORS For Commercial and Industrial Installations Through the eons man has benefited from radiant heat. First the sun and now the gas fired Overhead PANELBLOC takes over. With the speed of light healthful infra-red heat waves pleasantly warm ob jects and people without air disturbance. A few of PANELBLOC'S advantages are: No fan--ideal for dusty areas. No motor--quiet as a sun's ray. No power consumption--unit generates own oper- ating current. No costly electrical power installation charges. No possibility of shutdown due to power failure. No heat diverted by drafts from open doors or in . open pavilions. No fuel wasted heating unnecessary spaces in building. problems into routine installations. PANELBLOC spot-heats with no need for costly partitions or false ceilings. Infra-red heat like light goes only where di rected by the polished metal louvers. As a result peo ple, equipment and particularly floors are pleasantly warm. . . - CONSTRUCTION AND OPERATION The combustion gases, produced from any commer cial gas fuel pass through a unique panel heat ex changer of special steel. To overcome corrosion and high temperatures this heat exchanger is coated inside and out with vitreous enamel. The panel is heated to a carefully controlled temperature so that the infra-red waves (10 times longer than those from a glowing fire) produced have a wave length which gives maximum penetration. Maximum penetration means comfort heating. MODERN INFRA-RED METHOD (U- S. and Foreign Patents Granted) Developed to fill the gaps in Industrial and Commer cial heating, PANELBLOC turns difficult heating STYLE "A" LO-BOY Beater with separate blower section for by-pass application blowers other than standard can be utilised i.e. model 150 blower can be used with model 100 furnace for additional air capacity. STYLE "A" DUCT HEATER All heaters available as duct beaters in a variety of outlets and inlets tor use in conjunction with air conditioning equipment. STYLE "E" COUNTER FLOW HEATER With jet fired power gas burner top or side inlet for return air. STYLE "A" SUSPENDED OR LO-BOY Heater filter inlet top or rear. Discharge top or front. 3 STAGE OIL BURNER For makeup air, fluctuating loads, drying systems, heating and ventilating systems. Three individual burner heads, each com- . EVEN-FLOW HEAT EXCHANGER prising end cone, turbulator ring, nozzle and blast tube makeS' Multiple flue arrangement. Down flow of hot gasses gives a temperature equalising effect which distributes the generated heat uniformly over the entire flue area. Direct firing into combustion area .with no restrictions to block heat transfer to air stream. Stainless steel wrapper at combustion area. possible efficient air velocities and oil atomizing pressures for each firing stage. Integral draft inducing fan provides positive draft. Single motor for operation of both oil burner and draft inducer. Standard SUNDSTRAND 2 STAGE fuel unit. De layed action solenoid valves to each.burner head provides prepurge timing, control of oil for each firing stage and positive Hi-Boy, Counter Flow, Suspended, Lo-Boy Heaters in a Complete Range of Sizes--Choice of Firing Equipment. shut-off. Electronic control for fast, safe control. Standard ignition transformer. ENGINEERING DATA Model 33 GO 280 840 BTU Output CFM ' 8.P Isput Oil GPH 1.128.000 4200 8400 12000 2:00 8:00 10:00 Ntt Ges CFH - 180 230 280 400 GOO 800 1000 1400 Blower P.H. 4 Phase Volt 1/110 H m 2 RPM 680 560 520 500 450 480 No. Wheels Wheel Sue X 12 1 H X 12 1 14 X 14 1 l X 2 18 X 14 2 18 X 16 2 13 X IS 20 X 18 Filters Qua. Sue 4 16 X 20 4 20 X 25 8 . 16 X 23 8 20 X 25 12 20 X 23 WRITE for COMPLETE CATALOG and SPECIFICATIONS  128 MI Air Conditioning uai* Bnu ud c*u American Air Filter Co. Inc. Louisville, Kentucky Plants: Louisville, Ky. Chicago, IU. Moline, 111. Morrison, IU. St. Louis, Mo. HEATING EQUIPMENT HORIZONTAL SHAFT PROPELLER-FAN TYPE HEATERS For suspended mounting. Use with steam or hot water. Copper heating element with patented stay tube prolongs unit life. Many models and sizes. Bulletin 700. VERTICAL SHAFT PROPELLER-FAN TYPE UNIT HEATERS Designed for high ceiling installations. Long life copper heating element for use with either steam or hot water. Units available in range of capaci ties with high or low velocity discharge. Bulletin 700. . CONSOLE HEATERS Compact, quiet, economical and attractively styled. Ideal for offices, show rooms, corridors, stores, etc. May be placed on floor, wall or suspended from ceiling. 18 models and sizes. Bulletin 7S7. CONVECTOR RADIATORS (Not Illustrated) Range of axes for steam or hot water. Heating elements made of non-fer rous materials. Cabinets designed for free standing or recessed installation. Also sloping top models. Bulletin 791. FINNED RADIATION AND COVERS (Not Illustrated) Adaptable to any system as a primary or supplementary heating source. Range of sixes with choice of expanded metal, flat top or slant top covers. Bulletin 790. NELSON UNIT VENTILATOR SYSTEMS Herman Nelson Draft/Stop Systems automatically heat, ventilate, na tural cool (with outdoor air) and mechanically cool (with chilled water). Draft/Stop principle traps cold window drafts before they reach classroom occupants. For steam, hot water, electric heating, direct gas-firing, and hot water or chilled water for year 'round air conditioning. Bulletin 600. FANS AND BLOWERS PROPELLER FANS . A complete line of belt or direct drive ventilating fans. Twenty-nine sizes with wheel diameters from 10 to 54 in. Unit capacities ranging from 655 to 36,150 cfm. Bulletin 800. UNIT BLOWERS Direct or belt drive with forwardly curved or backwardly inclined wheels. Wheel diameters from in. to 36 in. and capacities from 160 to 18,303 cfm. Bulletin 866. CENTRIFUGAL FANS Designed for systems requiring a Class I or II centrifugal fan. Slow speed or non-overloading type. Wheel diameters from 1214 in. to 73 in., single or double width. Direct or belt drive. Any rotation or discharge. Bulletin 861. Oiu Heaten. Fea* BU*e American Air Filter Co. Inc. MI American Air Filter Co. Inc. Louisville, Kentucky AIR CONDITIONING UNITS Complete Air Treatment All basic air conditioning functions of heating, humidifying, cooling, dehumidifying, cleaning, and air movement may be combined in this one unit, providing true "year 'round" air conditioning. A Size for Every Application Twelve sizes, with air handling capacities of 675 cfm to 36,000 cfm matched with proper size cooling and heating coils of all styles and capacities make this a universal unit. No application is too small, none too large for this broad line. A Model to Fit Horizontal and Vertical models are available in all sizes to meet the modern need for compact, space-saving equipment. Bulletin 786. MULTI-ZONE AIR CONDITIONING UNITS Multi-Zone Air Conditioning Units maintain design conditions, under varying loads, in ALL zones of the system. This single central station Multi-Zone Unit can handle from 2 to 8 zones. Eight sizes, with air han dling capacities of 3,440 cfm to 36,000 cfm. Coils can be furnished for di rect expansion, chilled water, steam or hot water. One cooling coil and one heating coil in each unit (operating in parallel) supply correctly cooled, tempered or dehumidified air for perfect comfort under year-round con ditions. Bulletin 870. . HEATING AND VENTILATING-UNITS Feature sect-ionalized construction, low outlet velocities, slow fan speeds, wide selection of heating coils. Available with humidifier. Ideal for in stitutional, industrial and commercial use. Bulletin 910. ROLL-O-VENT AUTOMATIC AIR FILTER Offered exclusively by AAF, the Roll-O-Vent automatic air filter is avail able as an optional accessory with Air Conditioning Units, Multi-Zone Units, or Heating and Ventilating Units. Utilizing AAF's famous Roll-OMatic filtering principle, Roll-O-Vent assures constant air delivery at all times, makes filter changing automatic and gives major savings in main tenance. One roll of media can do the work of a year's supply of disposable filters at about one-half the cost. HEATING AND COOLING COILS A. Standard Steam Coils--Type S (Not Illustrated) Made with 5/s in. seamless copper tubing; spaced 8 fins per inch. Recommended for a maxi mum operating pressure up to 30 psL Over 30 psi, use heavy duty coils, type HS. B. Steam Distributing Coils--Type SD For use where steam supply is to be modulated and/or exposed to freezing temperatures. Bulletin 890. C. Standard Water Coils--Type W Made with Vs in. seamless copper tubing, spaced on V/t in. centers in depth and width. Fins spaced 8 per in. Coils are used for both heating and cooling. Also available with fittings to permit internal cleaning of tubes. Bulletin 880. D. Direct Expansion Coils--Type DE Aluminum or copper fins are bonded to % in. or 54 in. seamless copper tubing. Fins spaced 8 per in. Re frigerant circuits are of equal length and arranged for counter flow. Bulle tin 880. ' 129 Plants: Louisville, Ky. Chicago, IU. Moline, Hi. Morrison, 111. St. Louis. Mo. 1  130 Air Condiliutiing * Carrier Corporation Syracuse 1, New York UNIT HEATERS Carrier Unit Heater Agents, jobbers and distributors are located in ai] principal cities. Listed in your local Classified Telephone Directory under "Heaters, Unit" Carrier Unit Heaters are the product of more than half a century spent in the design and manufacture of temperature control equipment. For high and low pressure steam, forced hot water and gas-fired systems. Air Conditioning Hester: 131 FEDDERS CORPORATION HEATING DIVISION LALOR & HANCOCK ST. TRENTON 7, N. J. Representatives in Principal Cities 46S Four-Way Unit Heaters feature a variable "clover leaf" air discharge pattern through four separately controlled out lets. In eight sizes ranging from 55,000 to 600,000 Btu/hr. 46U Horizontal Unit Heaters heat areas with a conventional horizontal discharge pattern. Feature angle row, low air resist ance coils; in ten sizes ranging from 13,400 to 200,000 Btu/hr. 465D Vertical Unit Heaters mount within 2 inches of ceiling to save headroom. Available with standard or low temperature rise coils in ten capacities, from 30,000 to 576,000 Btu/hr output. 46AE Cabinet Unit Heaters include eight cabinet styles; free standing, variable semi-recesscd and recessed. Mount on floor, wall or ceiling. Capacities range from 26,200 to 115,000 Btu/hr. 46T Gas-fired Unit Heaters are compact in design and use Aluminized Steel heat exchangers for long unit life. Available in eight ranging in capacity from 50,000 to 230,000 Btu/hr. 46TD Gas-fired Duct Furnaces include eleven basic sizes from 50fiOO to 440,000 Btu/hr capacity. Companion engineered Blower Assemblies provide from 530 to 6500 cfm capacity. Carrier Heat Diffusers are designed to provide dependable heating and ventilating for large buildings or areas and for industrial process application. Available for steam, hot water or direct-fired installation. 46PQRV Heat Diffusers for steam and hot water systems * feature floor mounted or suspended units with "building block" of components for installation flexibility. Choice of fan- coil capacities to provide from 47,000 to 2,990,000 Btu/hr output. 46AF Heat Diffusers--Direct Fired are self-contained units for oil, gas or combination fuel. With stainless steel combustion chamber and heavy gage steel heat exchanger, they are A.GA. and UL approved in ten sizes from 300,000 to 2,000,000 Btu/hr. Showing compact installation of floor unit Exploded view showing accessibility of parts FEDAIR REMOTE TYPE AIR CONDITIONING UNITS Made in Free Standing, Recessed, and Overhead Models FEDAIR Units are for multiple room installations, in large and small buildings. They simplify planning of new and modernized buildings. No duct work ana only 3 lines re- uired--supply, return, and condensate drain. Aluminum nned copper tube coil gives quick response to controls. AJJ models available with motors for standard and low-speed operation. Blowers are sized to deliver rated cfm at specified motor speeds. Outside and recirculated air filtered. Write for complete catalog. '' FEDAIR overhead models are used . where floor and wall space is limited. Outlet louvers arc adjustable for direc tional control. Available without en. closure for concealed installations. FEDA IK BASIC CAPACITIES--ALL COOLING CAPACITY AIR FLOW QUANTITY CFM AT TO- F HIGH SPEED BTV/He 49* F- ENT. WATER WATER FLOW Ft. High ! s Low Mxx, Fresh Totxl Semi te 2Ai o HTO Pres sure LHCS1 819 189 139 LHC3J 810 290 810 85 6.710 4.830 1.7 89 10,793 7.8Q0 1.7 1.9 9.1 LHC43 430 339 879 110 14.900 10,000 3.8 -10.0 HLCW 809 490 410 180 10,100 13.900 4.8 7.1 MODELS (HEATING CAPACITY HIGH SPEED ISO* F. ENT. WATER Btn/Hr 18.700 28.9 87.900 80.4 >7,700 SI.8 53.100 SS.4 Temp. Drop FEDDERS MODERNLINE WALL RADIATION `Coding Cspxcity Booed on 86*F. DB, C7*P. WB Entering Ab Mixture witfc 8 . Water Te&perxtsre Rbe. ' t Heating Capacity lined w M*P. Entering Air Tcnpoatwe and indicated water flow. FEDDERS BASEBOARD RADIATION MODEL BBH Complete With Deflector Damper . ^ SMOOTH ROUNDED COVERS, available in 3 heights and 2 depths, combine attractive appearance with functional con nected and radiated heat emission. Integral die-formed louvers direct heated air outward into room. Covers finished with baked-on ivory enamel or Quaker gray neutral prime. Can be furnished in five other colors. HEATING ELEMENTS can be used with steam or hot water systems and installed one or two rows high. ML-5 elements have in. copper tubes with 4^ in. square .025 in. aluminum fins in lengths from 2 ft. to 12 ft. in increments of 6 in. ML-5 steel elements avail able.with 1}4 in. and 2 in. IPS and in. square fins. Write for catalog. FEDDERS Baseboard Ra diation provides completely packaged, factory assem bled units for easy handling and time saving installation Standard lengths are 4-ft, 6-ft, and 8-ft with other lengths available for large projects. Three series--Model BBH, Model S, and Model L provide ratings and prices to fit every iob Write for catalog. ALSO MANUFACTURERS OF HORIZONTAL, DOWNBLOW, AND CABINET UNIT HEATERS CONVECTORS, AND CONTINUOUS CONVECTOR RADIATION '  132 Air Conditioning tail Heater* ui 133 H in. Tube Coil 3^ in. Tube Coil % in. Tube Coil McQUAY RIPPLE-FIN COILS The famous McQuay Ripple-Fin coils are made in three tube diameters; % in., Yi in. and in., in a wide variety of styles and sizes for steam, hot water, cold water, direct expansion and refrigerant condensing. "Custom Engineered" coils are readily obtained, as McQuay's manufacturing methods provide a wide variety of fin spacings, fin heights, finned lengths, rows deep and circuiting, thereby both space and capacity requirements can be met. . Ripple-Fin coils have all tubes mechanically pres sure bonded into wide smooth fin collars providing a permanent bond and a high heat transfer efficiency. McQuay coils are pneumatically tested under warm water at 315 psig. Ripple-Fin coils have a staggered tube pattern which, combined with the ripple fin, produces a turbu lent air flow and reduces air "by-pass". . In addition to the ripples across the air flow, the fins of McQuay coils have rippled edges to give strength and a pleasing appearance. McQuay evaporators and condensers are dried with minus 40F dew point air to assure moisture-free coils. McQuay Ripple Fin coils have been approved by Underwriters' Laboratories for use as evaporators or condensers with either R-12 or R-22. Direct Expansion Coil Water Coil Steam Coil "AX." Aircon Vertical Air Flow Evaporator [\/lc Quay I V leansNj^uality McQUAY AIR COOLED CONDENSERS Fifteen sizes of belt drive commercial propellers and centrifugal fan models up to 50 tons capacity in a single unit. Split circuiting systems and winter control sys tems are available for all models. Centrifugal fan models are available with filters, face and by-pass dampers, intake mixing boxes, discharge diverting. boxes and humidifiers for combination condenser, ventilator and heating applications. Write for free bulletins. McQUAY RESIDENTIAL EVAPORATORS Five models of vertical residential evaporators rang ing from 26,000 to 90,000 Btu/hr constructed for either up flow or down flow of air. The horizontal residential evaporators range from 25,300 to 92,100 Btu/hr in five models, and are designed for air flow in either direction. Both the vertical and horizontal circuits are for use with R-12 or R-22. "AB" Aircon Horizontal Air Flow Evaporator McQUAY UNIT HEATERS Horizontal, down flow and cabinet unit heaters are available in an extremely wide range of sizes and ca pacities for either steam or hot water. Adjustable louvers are standard equipment on horizontal unit heaters. Down flow unit heaters are furnished with adjustable radial diffusers. There are three types of cabinet unit heaters--floor, wall and ceiling--all for Horizontal Unit Heater. . exposed, semi recessed or fully recessed mounting. `Rli" Air Conditioner Ceiling Type Seasonmaker SEASONMAKER Air Conditioning Units Individual room and large capacity air conditioners, four types--floor, hideaway, basic and ceiling. Cooling and heating medium supplied from central plant. Cools, dehumidifies and filters in summer. Heats and filters in winter. Five sizes of all models--200, 300, 400, 500 and 600 cfm. Hideaway and ceiling types also available with 800, 1200 and 2,000 cfm. The Seasonmaker's compact ness, only 8J in. deep, attractiveness, quiet operation and ease of installation make it ideal for hotels, apartment buildings, motels and other multi-room buildings. Down Flow Unit Heater Cabinet Unit Heater Basic Type Seasonmaker Floor Type Seasonmaker I V leans\^/uality HEATING AND VENTILATING UNITS Horizontal, vertical, wall and inverted types available. Covers the entire range to 48,000 cfm and 3,320,000 Btu. Filters, face and by-pass dampers, mixing boxes, humidifiers, discharge plenums and nozzles are avail " able. Special units for school applications. Hideaway Type Seasonmaker Horizontal Heating and Ventilating Unit Vertical Heating and V'entilating Unit Horizontal Multi-Zone Air Conditioner Horizontal'Type Seasonmaster MULTI-ZONE Heating and Cooling Units One unit simultaneously heats and cools up to 22 separate zones. Eleven sizes in horizontal or vertical models with capacities from 1350 to 38,000 cfm. SEASONMASTER Central Station Air Conditioning Horizontal and vertical types. Cool, dehumidify, filter and circulate air in summer. Heat, humidify, filter and circulate air in winter. Direct expansion and water , cooling coils. Steam and water heating coils. Cooling capacities to 200 tons, from 640 cfm to 38,000 cfm in both suspended and floor types. Vertical Multi-Zone Air . Conditioner Vertical Type Seasonmaster i !  134 Air System Equipment . Unit Hesti ILG ELECTRIC^ VENTILATING COMPANY 2880 N. Pulaski Road Chicago 41, Illinois Offices in 57 Principal Cities Member of Air Moving and Conditioning Association, inc. (AMCA) ILG UNIT HEATERS--STEAM, HOT WATER, ELECTRIC OR GAS Tested and rated by IUHa and ASHVE Codes. "One-Namc-Plate" guarantee. ALL-ELECTRIC UNIT HEATERS ILG ALL-ELECTRIC UNIT HEATERS--new design for lit to 36 kw. features black heat type steel-sheathed elements and Ilg's quiet Type "Q" fan wheel. Built-in thermal cutout and direct-connected, totally enclosed motors. Heavy-duty construction throughout for heatmg isolated areas, temporary or auxiliary heating, stand-by freeze prevention, etc. Send for Bulletin 808. '. STEAM AND HOT WATER UNIT HEATERS ILG VERTICAL-TYPE UNIT HEATERS--new de sign. Totally enclosed ball-bearing motors. Heating surface features similar to horizontal type. Type "V" for standard outlet temperatures, Type "VL" for low outlet temperatures. 15 capacity sizes. Send for Bul letin ISOS. CABINET HEATERS ILG HORIZONTAL-TYPE UNIT HEATERS--four side pipe connections for simplified piping. Suitable for hot water and steam to 150 lb pressure... tubes air-tested to 90 lb. Motor totally enclosed, continuousduty type. 19 capacity sizes. Send for Bulletin ISOS. GAS-FIRED UNIT HEATERS Air Conditioning Halt Hiiaten 4 CmIh* 135 D. I. MURRAY MANUFACTURING CO. WAUSAU WIS. Offices IN PHINCtPAl CITIES ' . MANUFACTURERS OF GRID CAST IRON UNIT HEATERS, BLAST HEATERS, RADIATORS. CW/IMW in HEATING EQUIPMENT WHEN YO U INSTALL----------- CAST IRON STEAM HEAT GRID TRANSFER SURFACE You once and for all eliminate internal electrolytic corrosion because all metals in GRID Cast Iron Steam Heat Transfer Surface : that are in contact with steam are similar . . . not 2 or 3 different metals that promote eorrosion to cause leaks and breakdowns. GRID Cast Iron Steam Heat Transfer Surface also largely eliminates external corrosion because its cast iron construction resists acids or fumes in the air. When corrosion in heat transfer equipment ends, high maintenance ends *. . . it's as simple as that, no mystery, no magic, no "sales" talk. Your heating problems are no longer problems . . . you do away with high maintenance costs, repair work ana the nuisance of leaky heating equipment. ` GRID Cast Iron construction is designed to withstand steam pressures up to 260 p.s.i. . . . 450 deg temperature eliminating the use of reducing valves where high steam pressures are used. GRID Cast Iron Steam Heat Transfer Surface largely does away with replacement costs because GRID is built to last for years . . . operating successfully without maintenance in many plants since 1929. Sounds worth looking into? Then get the complete story today . . . come the heating season, you will be glad you did. GRID HORIZONTAL BLOW UNIT HEATER DATA 29 YEARS MAINTENANCE-FREE Unit Hester . Model Citinj; 'Uimatuon Center Width Height Orer all Height Center Hanger Rod Motor Hp Rpm Cepedtie, el 2 PS1G Stem Pipe Size 60* F Eol Air VoL Fen Cfm Btu Per Sap- Re- Hr S ply 'fET Itod Wl Die. Lb*. SERVICE ON ALL TYPES OF GRID EQUIPMENT CMOQO 13H ISM, 15M, 11 CI-I200 15V4 ISH* ISM, 15 46* 1550 570 27720 103 1V4 IVi M* 1700 800 43320 109 1V4 IVi H H 150 210 CMSOO Cl-1520 1155 16 11 Cl-2000 2044 21 CI-202S am 26 CI-2SM 2SM 26 Cl-2500 2SV4 26 229 * 34 36H 35H 1744 17H 22H 23*6 2714 27V4 Vi 1750 1500 73000 104 144 114 Vi 17S0 1700 96730 112 IVi i Vi Vi 1150 2600 134000 107 2 1V4 Vi 1150 2875 163900 112 2 IVi 55 1150 3300 196000 114 1150 4350 213500 104 2 2 IV4 IV4 44 44 44 h Vi Vi 280 390 490 520 680 700 CI-2530 2Sf4 31 CI-3000 3tm 31 CI4000 am 31 40H 2744 Vi 1150 4650 283500 111 2 1V4 H 900 JS55 32Vi Vi 850 5900 305000 107 3Vi 1V4 32H IVi 1150 3000 382000 101 2Vi 144 Vi Vi 1020 1070 ILG SERIES "A" CABINET HEATERS--designed for maximum flexibility of arrangement and operation. Can be furnished for'floor, wall, ceiling or inverted mounting. Available in seven basic unit sizes, 35 models. Blow-through type with direct fan assembly and drawthrough type with belt-drive assembly. Equally suitable foT steam or hot water applications. Send for Bulletin isoe. ILG GAS-FIRED UNIT HEATERS--use natural, manufactured, mixed, butane-air mixtures; propane, or butane gas. Available in 10 basic model sizes, 2 types: Propeller Type (Series M); or Blower Type (Series MB) for use with duct work. Safety pilot, auto matic control valve, electric limit switch. Motor has thermal overload protection. Send for Bulletin S86. Grid Blast Heaters in Fan Assembly A rugged, strong, and economical heat transfer surface, GRID BiastHeaters are designed for the tough job . . . for low and high steam pressures . . . require less labor for installation, -less cubical space, and being designed and made the same as GRID Unit Heaters are resistant to corrosive atmospheres . . . definitely proved for years of service and maintenance-free. Grid Cast Iron Radiator Can be furnished with protective grill Designed for the tough applications in conjunction with high steam pressure systems, GRID Radiators eliminate the use of pressure reducing valves and because they are built with the same heating sections as GRID Unit Heaters, they will with stand steam pressures up to 250 psi . . . and wide fin spacing prevents collection of dust and dirt . . . particularly adaptable tor factory, shop offices, store rooms, laboratories, etc.... any lace where smaller heating capacities than required of a unit eater are needed.  136 - Air Conditioning THE TRANE COMPANY LA CROSSE, WISCONSIN TRflnE manufacturing engineers of air conditioning, heating, ventilating, and heat transfer equipment Akko-V. Ohio Aluaxv, fi. V. ALatQCUQCE, N. it. Au.C.VTON, Pa. Av.iiiuo, Texas Am.m.v, Wb, AL'BOBA, ILL. Baitiuoii!, Mo. Baton Rocoe, La. Bilunos, Mo.vt. Biuii.vciiau, Ala. Boston, Mam. Buffalo, N. V. Cavtox, Ohio CHARLESTON. W. V'A. Chablotte. N. C. Chattanooga. Tenn. Chicago, III. Cincinnati. Ohio Clarksuiho, W. Va, Clcvelaxo, Ohio Colcubia. S. C. Cqlvkecs. Onto Dallas, Texas Daventojit. Iowa Davton, Ohio Dexa'o, Colo. Des Moines, Iowa Dltboit. Mich. Dclctm, Minn. Fargo, N. D. Flint, Mich. Fobt Wayne, In. ' Gainesville, Fla. (Grand Rafids. Mich. Greensboro, N. C. Greenville, S. C. HHoarurstuobno,bToe, xPaas. Indianapolis, In. Jackson, Miss. Johnson Cm, Tenn. Kansas Citt, Mo. Knoxville, Tenn. La Crosse, Wo. Lansing, Mica. I.os Angeles, CalivLocisville, Kt. Memphis, Tenn. Miami, Fla. Milwaukee, Wis. Morristown, N. Y. Nashville, Tenn. Newark, N. J. New Orleans, La. New York, N. Y. N. Tarrttown, N. Y. Oklahoma Citt, Okla. Omaha. Nebr. Pensacola. Fla. Peoria, III. PHn.APELWtm Pa. Phoenix, Arix. Pittsbcbch. Pa. Portland, He Portland, Ore. Pbovidewcr, R- I. Ralexob. N. C. Richmond, Va. Roanoke, Va. St. Loots, Mo. St. Paul, Mum. Sacramento, Caut. Saouaw, Mm. Salt Lake Cm, Utah San Antonio, Texas San Diego, Calif. Bam Framcoco, Calif. S>8 TRANE SALES OFFICES IN UNITED STATES REFRIGERATION Savannah. Oa. SSehartetvleep,oWrta,sIh,.a. Sioux Falla, &. D. South Brno, Ind. Spokane, Wash. Steaccbe, N. Y. Tamta, Fla. Toledo, Ohio Trumbull, Cora. Tulsa, Oxla. WaRhinoton, D. C. West Hartford, Cora. WWkilhkiitsa-B, aKrarnes.. Pa. Wllminoton, Dr. 1. HERMETIC CENTRAVACS ' Hermetic centrifugal refrigeration unit--a complete water- chilling system. CenTraVac features automatic capacity con trol. No seals or gears. Capacities range from 45-1600 tons; 32 sues. Unit performs efficiently at operating levels down to 10 percent of rated capacity. . 2. TURBINE CENTRAVACS Centrifugal water chillers combining CenTraVac compressor design and steam turbine drive. Integral assembly of com- presor and turbine eliminates critical field alignment problems. Sues from 300 to 1600 tons. - 3. RECIPROCATING COMPRESSORS Two cylinder sizes in 4, 6, and 8 cylinder units. Single or du plex direct drive arrangements with capacities from 10 to 150 tons. ,. 4. COLD GENERATORS Complete factory-assembled packaged liquid chillers, de signed to meet all normal requirements of chilled water sys tems. Only simple water and electrical connections, are neces sary for installation. No special foundations are required. Available with capacities ranging from 10 to 150 tons; using Refrigerant 12 and Refrigerant 22. Automatic chilled water temperature controls are also available. ' 5. CONDENSING UNITS Trane Reciprocating Compressor complete with water cooled condensers. Capacities 10 to 150 tons; Refrigerant 12 ahd Re frigerant 22. - 6. EVAPORATIVE CONDENSERS For installations in localities where the use of water for con densing the refrigerant in the air conditioning system is re stricted, or where disposal of large quantities of water is a problem. These units condense Refrigerant 12 and Refrigerant 22 by the evaporative process using a constantly recirculated supply of water. The only water lost is that which is evaporated to cool the water being circulated. Sizes' from 3 to 100 tons. Unit HttKn tad Colm 137 The Trane Company 7-8-9. SELF-CONTAINED CLIMATE CHANGERS Packaged air conditioning units for offices, shops, commercial or industrial air conditioning. Available in 8 anw--20 models ranging from 3 to 30-ton. The 3, 5, 8, 10, and 15 sizes have deluxe cabinet design to be installed in the conditioned spaoe and blend with any surrounding. The commercial units avail able in 10, 15, 20, 25, and 30-ton sizes are usually installed in a remote location, outside the conditioned area. Deluxe units available with water- or remote air-cooled condenser. 10, 15, and 20-ton commercial units available with integral evaporative condenser; 20, 25, and 30-ton sizes with either water-cooled or air-cooled condenser. 10. RESIDENTIAL CLIMATE CHANGERS Heat, cool--or both--with this year-round unit. Cooling unit (top section) may be added later. 2,3, and 5-ton sizes. Heating unit (lower section) comes in complete range of sizes from 77,000 to 154,000 Btu. Gas-fired. A-GA. approved. Residential Climate Changer Bonnet Cooling Unit fits atop Trane heating unit--or other modem makes. Compact 2, 3, or 5-ton capacity cooling coil. Residential Climate Changer Fan-Coil Unit for cooling with independent heating system. Unit, with own quiet centrifugal fan, distributes cooled, dehumidified air. Built-in .filter clean* air of dust and dirt. Fits anywhere. 2, 3, and 5-ton sizes. Residential Climate Changer Duct-Cooling Unit for special applications. Same engineering, same capacity as bonnet type unit. 11-12-13. UNITRANE . UniTrane room air conditioners beat, ventilate, filter and cir culate air in the winter. In summer, they cool, ventilate, filter, control moisture content and circulate air. Available in both fan-coil and induction types. Wide range of sizes and models-- free standing, recessed, semi-recessed, ceiling-suspended--for exposed or concealed installation. Capacities for 100 to 600 cfm delivery. Automatic Air Flow Regulator provides permanent hftluneing for Trane high pressure induction air conditioning . systems. Acts automatically to assure proper air delivery and performance. Factory-installed for cither left-hand or righthand air supply. System is balanced in a single initial operation; requires no periodic rebalancing thereafter. - 14-15-16. CLIMATE CHANCERS Any or all ph**p of air conditioning available in one unit. Two models, horizontal and vertical, each in 12 different sizes. Ca pacities range from 600 cfm to 39,000.cfm for any application, comfort or process. Multi-Zone Climate Changers provide a number of zones with different air conditions at the same time. Temperature in each zone is automatically controlled by sepa- y' rate set of dampers, making it possible to heat in one zone, while cooling in another. Humidifiers and filters, optional. EDUCATIONAL MATERIAL "Trane Air Conditioning Manual" ($650), an unbiased 380-page textbook for the engineering profession. New revised edition now available. Many tables and charts included for making computations. In general, text covers heat gains, psy- chrometry, calculations for the conditioned air supply, refriger ation for air conditioning, water for air conditioning, and ducts and fans. "Trane Refrigeration Manual," a reference for servicing and installing all types of refrigeration systems. Also available from The Trane Company, La Crosse, Wis. Price $200. ` i ti  138 Air Conditioning THE TRANE COMPANY HEATING AND VENTILATING 17-18. CONVECTORS For all steam and hot water systems. Type C--immediately available in many standard sizes. Other units for specific ap plication problems. ' 19. WALL LINE CONVECTORS High capacity radiation designed to run continuously below window expanses. Cabinet depths 4 in. and 6 in, heights--14 in, 20 in, and 26 in. Top and front outlet. .Chain-type or dialtype knob dampers, optional. 20. BASEBOARD CONVECTORS . . Non-ferrous fin-and-tube heating element. Attractive steel cabi nets, 8Yt in.` or 12 in. height. Damper or valve controls, op tional. 21-22-23. WALL-FIN * Ferrous and non-ferrous finned radiation. Lengths 2 ft to 12 ft in 6 in. increments. Cabinets and expanded metal grilles avail able. Grille louvers two inches in length for greater strength. Ball bearing cradled elements minimize expansion-contraction noise. Spiral damper control for positive temperature control. Enclosures phosphatized and primed after spot welding to pre vent rusting. 24. PROJECTION UNIT HEATERS ` Model "P" taps the reservoir of ceiling heat, solves a multitude of heating problems. Available in 24 sizes, steam or hot water. Capacities from 40,000 to 560,000 Btu. Louver Cone diffuser, optional. 25. HORIZONTAL UNIT HEATERS Combines Trane broad blade propeller fan and extended sur face coil. In 24 sizes, 22,000 to 352,000 Btu. Louver Fin diffuser, optional. - Gas-fired Unit Heaters available in six suspended type models, all A.GA. approved for use with any type of gas--natural, manufactured, mixed or liquefied petroleum. One-piece Hori- ' zontal-Tube Heat Exchanger combines combustion chamber, heating surface, draft diverter and fiue outlet in a single com pact unit. Patented Louver Fin Diffuser, optional. All units carry Underwriters' Laboratories Seal of Approval. 26. STEAM SPECIALTIES * . Complete line including thermostatic traps, valves, float traps, bucket traps, strainers, vents and temperature control valves. 27. TORRIVENT Large capacity heating and ventilating units combining Trane Centrifugal Fans and extended surface coils for heating and ventilating large spaces and for process applications. Available in 1, 2, or 3-fan units. Choice of 3 coils. Designed for air de liveries ranging from 1150 to 36/100 cfm and for heating capaci ties from 50,000 to 1,900,000 Btu. Four models available in nine sizes. ` T ^ and Cwlrn 139 THE TRANE COMPANY 28. ROOF VENTILATORS Complete line of axial and centrifugal roof ventilators for wide variety of applications. Units for exhausting air, for supplying air--units that supply heated air for comfort conditions or process work in the winter season. 29. FORCE-FLO HEATERS Deluxe cabinet-type unit heater .with centrifugal fan. Capaci ties: 17,700 to 142,000 Btu. 30: UNIT VENTILATORS Kinetic Barrier System with lateral extensions the length of the outside wall provides constant protection against window downdrafts. Conventional discharge type units with all air being delivered from the unit itself, also available. Automatic ' or manual temperature control. Quiet, belt-driven operation. Matched components and accessories. 31. SHELVING Available for Kinetic Barrier and conventional unit ventilation in open or closed type. Three sizes with fill-in sections to make wall to wall installations. 32-33-34-35. FANS Centrifugal fans in non-overloading backwardly inclined or alow speed forward curved types. All standard arrangements in sizes from 12 in. to 89 in. Capacities 668 to 330,048 cfm. Utility fans, both belt-driven and direct connected, in non overloading backwardly inclined or slow speed forward curved types. AU standard arrangements in sizes 4Yt in. to 30 in. Capacities 110 to 15,450 cfm. Cabinet fans in size 1-7 through 2-27. Capacities 587 to 39,499 cfm. Propeller fans with direct or belt drive. Sizes 10 in. through 72 in. Capacities 475 to 58,560 cfm. * 36-37-38. EXTENDED SURFACE COILS HAftting coils include a complete range of same and opposite end connection- steam distributing tube coils, standard coils, heavy duty, high presure steam coils, and equipment coils. Cooling^coils are manufactured for direct expansion or wa ter cooling in -thousands of sizes and types. AU extended surface coils have exclusive Delta-Flo Fin for greater heat transfer efficiency. i i .I  140 Air Conditioning Una h. Office and Factory LINDEN, N. J. L. J. WING MFG. CO. Division of Aero Supply Mfg. Co. Inc. 59 Vreeland Mills Road, Linden, N. J. Canadian Factory: MONTREAL Branch Offices in European Representative for Heaters: Principal Cities Wanton, Haren-Nord, Brussels, Belgium WING REVOLVING UNIT HEATERS ONLY WING OFFERS THESE ADVANTAGES Distribution outlets slowly revolve--assuring 1--Complete distribution of heat over wide areas--around obstacles 2--No uncomfortable steady blasts of heated air 3-- nI creased worker productivity Multiple outlets direct heat in multi-diameter circles. Area entirely cov ered. Fewer heaters needed. Minimum installation, maintenance and fuel costs. For steam, hot water, electricity, gas. Summer operation gives refreshing breezes--closest approach to air conditioning. Write for Bulletin HR-6A. Four types of discharges permit mounting heights from 8 to 60 feet. -. WING FRESH AIR SUPPLY HEATERS Wing Fresh Air Supply Heaters (right and left) provide "make-up" for ex hausted air and for health, comfort and efficiency of workers and for im proving processes. illustrations show 4 way discharge for low ceilings. Other outlets for high and medium ceilings are available. Coils cannot freeze... steam always at full pressure. Temperatures automatically controlled. For roof or window mounting... horizontal or vertical discharge. Write for Bulletin FAS-1.. * OTHER WING HEATERS Left. . . Wing Door Heater. Blasts curtain of hot air over open doorways. Keeps cold drafts out. Right . . . Wing Utility (Horizontal Discharge) Unit Heater. Steam, hot water, gas, electric. Right . . . Wing Revolving Gas Fired Unit Heater --Self contained for overhead mounting and downward discharge. Output capaci ties to 368,000 Btu per hr. * Draft fiu, I.Jorm BU*en L.J. Wing Mfg, Co. WINGFOIL VANEAXIAL FANS Wingfoil Direct Drive Vaneaxial Fan has sealed motor within the casing. Sizes 10 in. to 42 in. Wingfoil Elbow Fan replaces elbow in run of duct. Motor, outside the casing, remains cool and clean. All deliver large volumes of air for size of fan without vibration. Capacities to 95,000 cfm. Write for Bulletins. Wingjet Power Roof Ventilators discharge hot or contaminated air high above building. Two types available: motor inside or outside airstream. Bulletin PV-1. . Wingfoil Straightline Vaneaxial Fan forms part of straight line of duct. Sizes 10 in. to 60 in. WING BOILER DRAFT EQUIPMENT WING DRAFT INDUCERS 141 'S' S' Wing Packaged Draft Inducers for Heating or-Power Boilers furnish uniform, adequate draft regardless of wind or weather. Tall chimneys be come obsolete. Factory assembled, easy to install in minimum space. Capacities available for all sizes of heating boilers. In power boilers up to 120,000 lb of steam per hour. Send for Bulletin 1-68. WING FORCED DRAFT BLOWERS Wing Motor. Driven Blowers. For volumes to 50,000 cfm. Statics 24 in. Manual or automatic regulation through Voltrol Vanes down 10 per cent of maximum. Static efficiencies to 80 per cent. Mountings he zontal or vertical. Send for Bulletin FD-4- X Wing Turbine Driven Blowers. Easily installed on burner fronts or boiler settings. Capacities to 50,000 cfm and statics to 15 in. Exhaust is oil free. Bulletin FD-4- Wing Dual Drive Blowers provide both turbine and motor drive, either available at will of operator. Send for engi neering data. Wing Steam Turbines for driving pumps, fans, compressors, etc. are sturdy, dependable sources of auxiliary power. Capacities to 150 bhp. Pressures to 600 psi. Temp, to 750F. Speeds to 4000 rpm. Bulletin T-64.  142 Air Conditioning - sail JOHN J. NESBITT, INC. State Road and Rhawn Street, Philadelphia 36, Pa. SALES: HEATING AND COOLING SURFACE sold by representatives of John J. Nesbitt fnc.; SYNCRETIZERS, AUDICON. ROOMMATE. WIND-O-UNE & THERMOVENTS sold by Nesbitt and American Blower Corporation; BASEBOARD RADIATION & GAS FIRED UNIT HEATERS sold through Wholesalers; ^i. SILL-LINE RADIATION & UNIT HEADERS sold by John /. Nesbitt. Inc. Products!. Heating, Ventilating and Air Conditioning Equipment -- Heat Transfer Surface (steam and water). Heating and Ventilat ing Units, Baseboard Radiation, Sill-line Radiation, and Unit Heaters (steam, water and gas-fired). NESBITT HEATING AND COOLING SURFACE Series T. Trombone shaped tubes distribute even smallest amount of steam uniformly under . modulating valve control. Maximum freeze-up protection. Ideal for pre-heating outdoor air. Avail able with steam and condensate connections at same or opposite ends. Copper tubes. Aluminum or copper fins. Lengths l2r to 120'. Publication 305-1. Series H. Efficient blast-coil surface for general heating, ventilating and air conditioning, or drying in high and low pressure systems. Seven types; full range of sizes, capacities. Publication 301-1- Series W. For cooling, dehumidifying or heating. Type WD has exclusive Nesbitt drain feature Surface pitched in casting. Freeze proof. Type WB for booster heating or air cooling where drain is unnecessary. Pub. 246. Type WC features deanable tube sections. Pub. 255. . THE NESBITT SYNCRETIZER The beating and ventilating unit for classrooms that provides quick, economic heat without over heating; draft-free ventilation and natural cooling when needed. A fully automatic, quiet operat ing unit adaptable to four cycles of control. Models to deliver from 750 to 1560 c.f.m. anemometer rating. Publication 10-1. NESBITT WIND-O-UNE RADIATION SYSTEMS Hezbitt Syseretixer with storage cabinet com poaeats Finned radiation, operating in conjunction with the Syncretizer, solves special'' problems of cold windows and walls. May be concealed by wall hung enclosures or storage cabinets. Provides positive protection against downdraft. 450, 550 and 700 Btu ft, capacities. SERIES WIND-O-LINE SYSTEM combines the Syn- cretizer with Wind-O-Line Radiation on a hot water system to reduce mechanical costs and. at the same time, increase the efficiency and quality of the system. Pub lication 10-1. NESBITT SERIES T THERMOVENTS For heating and ventilating large auditoriums, gymnasiums; cafeterias, assembly halls and similar gathering places, Nesbitt Scries T Thermovents are available in capacities up to 15,000 c.f.ra. standard. For high- ot low-pressure applications, steam or hot water. Acoustically "silenced" for quiet operation. Pub. THE NESBITT YEAR-ROUND SYNCRETIZER Quietly promotes classroom learning by providing balanced heating, ventilation and natural cooling during cold weather... ventilation and mechanical cooling during hot, humid weather. Fully automatic. One-piece motor and fan assembly. Models from 500 to 1500 c.f.m. Publication 11-1. 20-1. THE NESBITT AUDICON THE NESBITT ROOMMATE Sound engineered for large occupancy spaces such as' auditoriums, libraries, cafeterias. Provides heating, ventilat ing and natural cooling in winter; ventilating and mechanical cooling in A year-round cabinet conditioner for both winter heating and summer cooling. 7 Standard models. Complete range of air volumes from 200 to 1400 c.f.m.; cooling capacities 1 to 5 tons; heating capacities summer. The latter may be installed initially, or added at a later time. Available in high or low pressure models from 1,250 or 15,000 c.f.ro. Cooling from 3 to 60 tons. Heating capacities from 40,000 to 1,500,000 Btu. Pub lication 22-1. 25 to 100 MBH. Large variety of recessed, semi-recessed, universal and built-in ar rangements possible due to versatility of intake and discharge locations. Outdoor air dampers optional. Install for heating only, if desired... add mechanical cooling in future. Publication 600-1. NESBITT SILL-LINE RADIATION . High capacity finned radiation for perimeter heating in commercial and institutional buildings. Attractive 16-gauge enclosure, rigid one-piece back. Five casing styles, 8 lengths in baked enamel finish. Code ratings, 2.9 to 12.1 sq. ft. EDR. Publication 30-1. NESBITT UNIT HEATERS Propeller-Fan Unit Heaters feature universal coils of continuous-tube design -- perform equally well with either steam or hot water. Made for high water capacities and temperature drops. Male coil connections through casing rear provide maximum headroom. Sound rated in accordance with A.M.C.A. test code. Modern heavy gauge steel casing; green hammered-tone finish. Eight basic 24 models, 15,000 to 335,000 Btu/hr. "Giant" Blower-Fan Unit Heaters. Economical beat for large areas. Floor- mounted. wall-mounted, ceiling suspended types in wide capacity range. Giants of efficiency and endurance. Twelve sizes, choice of 20 heating elements, steam or hot water; 1, 2, or 3 fans; for heating and/or ventilating; from' 2000 to 28000 c.f.m., 83.000 to 1,735,000 Btd. Pub. 404. Publication 401. little Giant Unit Heaters. Versatile, draw- "Giant" Unit Heater *' through propeller fan units in 34 models from 34,000 to 684,000 Btu/hr; universal heating elements for steam or hot water; side piping for close-to-ceiling mounting; wide variety of ontlets; code rated for sound and capacity. Publication 402. Series A Cabinet Heaters for steam or hot water. Smartly styled, com pact, quiet, trouble free. Ideal for Gas Fired Unit Heaters. New, light, compact Series K models provide dean, economical, automatically controlled beat for commercial and industrial applications. Ten sizes from 25,000 to 250,000 Btu per hour input; approved for all types of gases. Sound rated.- Publication 400. offices, lobbies, corridors. 7 Standard models, 71 to 545 sq. ft. EDR; 265 to Gen Fired Unit Heater I860 c.f.m. Four Blow-Through types have direct drive fan assembly. Three Draw-Through types available with belt drive Ian assembly. Available for recessed, semi-recessed or nonrecessed mounting. Full selection of intake and outlet locations. Pub . AH'ratings of Nesbitt Unit Heaters are based on tests made in accordance with the standard test code of the Air Moving and Conditioning Association and the American Society of Heating and Air Conditioning Engineers. lication 403. Air Conditioning unit Heater* ud Cwkn 143 HEATING, COOLING, AIR CONDITIONING PRODUCTS FOR HOME AND INDUSTRY, HEAT TRANSFER PRODUCTS FOR AUTOMOTIVE, AVIATION, AGRICULTURAL. INDUSTRIAL, GAS AND DIESEL ENGINE APPLICATIONS General offices: Dept. 549, Racine, Wisconsin, U.S.A. Factories at Racine, Wisconsin and Mattoon, Illinois Soles and Engineering Representatives in All Principal Cities CONVECTORS & UNIT HEATERS Convectors for steam or hot water systems are available in a ^ wide range of sizes and six standard cabinet styles to fit all applications. Also available in institutional, low-level and bath room models. Vertiflow Unit Heaters for use in steam or hgt water systems are available in 22 models with sizes and capacities that range from 52/500 to 1,062/)00 Btuh. Excellent for heating industrial w buildings, garages, warehouses, and large high-ceiling airplane ^ hangars. Outstanding Young feature is the through-stack motor ventilation which provides motor cooling. Units are fitted with Spreadaire diffusers, Anemostats, or Aerojet nozzles to meet specific air distribution requirements. Type H Horizontal Unit Heaters are built in 15 models; with capacities from 19,000 to 325,000 Btuh; for steam or hot water systems. Cabinet Type Unit Heaters-are available in 3 sizes, with ca- w Cries from 29,900 to 127,300 Btuh, and in floor mounted, wall- " ?, inverted wall-hung, and horizontally suspended models. Perimaheat Baseboard Convector for hot water service; ^ available in 6 and 8 ft lengths; capacity with 190 deg average water 787 Btu per linear foot. Accessories include end caps, reside and outside corners, and optional splitters or dampers. Gas-Fired Unit Heaters are available in eight sizes ranging in - capacities from 50,000 to 230,000 Btuh input. Have welded cor rosion-resistant aluminized steel combustion chamber and heat w exchanger; other important design features. ^ HEATING AND COOLING COILS Young manufactures a complete line of heating and cooling . coils for central heating or cooling systems. AU steam coils are ^ pitched in casing to allow proper condensate drainage. AIR CONDITIONING UNITS Young Type "CS" Central Station Air Conditioning Units are available in 10 sizes with capacities from 500 to 28,000 cfm, and in three models--Type H (Horizontal), Type V (Vertical), and Type MZ (Multizone). They can be assembled in any combina- . tion, from a simple ventilation installation to a complete air conditioning system, including heating and humidifying, cool- W mg and dehumidifying, and filtering. Their simplified sectional design makes it possible to select a unit to exactly fit the requirements of the job. Young "Roomaire" Conditioner is a remote-type room air conditioning unit that provides year-round air-conditioning of ^ individual rooms in multi-room installations. For use with hot " water and chilled water systems. Individual controls. Four sizes--handling from 200 to 600 cfm with nominal cooling capacities of y% to 1V4 tons. Four models--F and CF for free standing or concealed floor installation; H for horizontal in stallation; CH for concealed horizontal installation.  144 Air Conditioning vmu Buxn, Dwuk ttfCTROMOVE Complete line of ELECTRIC HEATING SYSTEMS for HOME-INDUSTRY-FARM Ktisms Of ROCHESTER 3, NEW YORK <OMMCRCtAl CONTROLS CORPORATION When you need advice in any field, you consult a specialist. Deciding on a beating system is an important matter--one that you do not undertake very often. Therefore, it is only natural and in the course of wisdom, that you will look to a specialist in this field. For more than 25 years Electromode has devoted its research engineering and manufacturing facilities predomi nantly to the design and production of electric space heating equipment, and is one of the oldest in the business. The Safety Grid HpatJng Element is an Electromode feature. All electric wires are insulated, embedded and completely sealed inside a finned aluminum casting. No exposed hot wires, no glowing coils and no danger of fire, shock, or bum. This finned alumi num camming spreads.the heat rapidly, resulting in higher effi ciency and greater economy. The built-in safety switch auto matically prevents overheating. The Safety Grid Heating Element is guaranteed for 5 years against any defect in material or workmanship. . For HOME and OFFIC& Fig. 1 WALL-TYPE HEATERS Electromode Wall-type Heaters are made in models *r>d capacities suitable for all - si*e rooms, ranging from 1320 to 4000 watts, with built-in thermostat or man ual control. Heat is fan-circulated at floor level. All have automatic thermal safety switch. The big room heaters have silver grey finish and cn be painted to match decor. The small room or bathroom heat ers are available in gleaming chrome or white enamel and are used as complete or auxiliary source of heat. See fig*. 1 and 2. Fig. 3 BASEBOARD HEATERS Fig. 4 fig. 5 RADIANT HEATING PANEL Designed so that a completely harmoni ous installation can be made which con forms to design and dimensions of any room. Matching blank sections, end Combines radiant and convection heat ing. Modem design with silver grey fin ish. With or without built-in thermostat. Capacity 1100 watts. See fig. 4. pieces and comers for carrying out un broken baseboard effect. The comfort of RADIANT CABLE HEAT radiant warmth along outer walls, under windows and across the floor, thermo statically controlled at the comfort level you select for each room. There's no in terference from Electromode Baseboard Coils of cable hidden in ceiling radiate . clean heat downward. Each room tem perature controlled by separate thermo stat. Cables are a measured length of special insulated electric wires; water Heaters. They're so out of the way along . proof; non-corrosive. Used in plaster, the walla just like regular baseboard. 00, 900, 1200 watts; 120 or 240 volts. See fig. 3. drywall ceilings, or concrete floors. Magic Seal coating prevents streaks on eeiling- See fig. 5. ----------For INDUSTRY----------- Fig. 6 Fig. 7 UNIT HEATERS Unit Heaters available in Suspension-type and Combination Portable and Suspen sion models. Capacities' from 1500 to 45,000 watts. Fine for auxiliary warmth in hard-to-heat areas and for complete heating in outlying building. Adjustable louvers for directing fan-circulated heat into working zone. Thermostat control available on all models. See fig. 6 for Suspension and fig. 7 for Portable and Suspension. The Electromode Commer cial and Industrial heater is specifically designed for quick, comfortable, warmth in factory departments, offices, super markets and other areas where its quiet operation is an asset. It is easily portable, or it may be mounted on swivel-type brackets. 5KW--240 volts--single or 3 phase--17,075 Btu. See fig. & Fig. 8 Fi*. 9 EXPLOSION-PROOF HEATERS Explosion-Proof heaters are specially en gineered for installation in hazardous areas where beat is required and danger of explosion exists. They conform to rigid safety specifications and are fully tested and approved by Underwriters' Laboratories for use in areas covered in Class 1. Group D hazardous locations. Used in places where atmospheres contain gasoline, petroleum, naphtha, solvent va pors, natural gas and where flammable gases etc. are made or stored. Convec tion type. Three models range from 2000 to 6000 watts. See fig. 9. BLAST COILS Consists of a bank of Electromode castaluminum heating elements mounted in a 16 gauge formed steel frame having a Fig. 10 Fig. 11 114 in. wide flange with Ke in holes on approximately*6 in. centers for mounting to air ducts. Complete wiring diagrams for special applications furnished on re quest. See fig. 10. Electromode Insert Duct Heater (fig. ID Safety and endurance is inherent in its construction. It was designed as a pack age unit ready for easy installation. The Safety-Grid heating element is your as surance of complete protection against fire, shock or bum. Safety switch auto matically breaks the service to the heater in the event of stoppage of air flow through the heater from any cause. It is an automatic reset type. Engineering help gladly given. For more information, see your supplier or write Dept. HVG-19, Electromode Divi sion of Commercial Controls Corporation- Air Conditioning *145 INDUSTRIAL ENGINEERING AND EQUIPMENT COMPANY 22 Haoley Industrial Court, St. Louis (Rrentwood) 17, Mo. <Eiaaato Electric Blast Coil Heaters for Installation in Ducts and in Package Air Conditioners . Total and Supplementary Heat Package Units sized to specifications SAVE) Design & layout work YOU /Field time Commercial, industrial, institutional, residential and governmental installations are heated by these pat ented unite. They offer the following advantages: 1. COMPLETE UNIT, ready for installa tion, eliminating design and layout work 2. SIZED TO FIT 3. THERMAL CUT-OUTS, furnished with each unit ... 4. WIDE SIZE RANGE INDEECO UNITS FOR PACKAGE AIR CONDI TIONERS. Write for Bulletin E97P showing 704'sizes to fit 20 manufacturers' package unite. INDEECO UNITS FOR DUCT-INSTALLATION. Write for Bulletin E97U showing 422 sizes. SPECIAL UNITS in both categories furnished at no extra cost. INDEECO Blast Coil Heaters are made to suit your specifications.,.You are not compelled to change your plans to meet our specifications. A FEW EXAMPLES OF USES 1. Primary source of heat 2. Booster, supplementary or. standby auxiliary heating -- 3. ZONE temperature control 4. Industrial applications - (Example: for major oil refinery, seven pumping stations without attendants are heated by INDEECO blast coil heater installations) Literature describes wide range of applications in de-. tail. More than 10,000 specifications on file. WRITE FOR CATALOGS CONSULTATION ON ANY PROJECT WITHOUT CHARGE 22,621 INSTALLATIONS to date 150 to 17,500,000 Watts Typical examples include: SUN-TIMES CHICAGO BUILDING, CADILLAC MOTOR CO., . DETROIT GENERAL FOODS CORP., WHITE PLAINS ROCKEFELLER CENTER, N. Y. CITY LOYOLA UNIV- NEW OR LEANS U. S. EMBASSY OFFICE, HONGKONC I. MAGNIN DEPT. STORE, PALO ALTO, CALIF. ST. LAWRENCE SEAWAY (U. S. AND CANADIAN SIDES) AND OTHERS INDEECO Electric Blast Coil Heater for Package Air conditioners as shipped and ready for installation INDEECO Electric Blast Coil Heater for duct installa tion. Listed by Underwriters Laboratories. Above is part of installation totaling 1,680,000 watte.  146 Air Conditioning Edwin L. Wiegand Company 7672 Thomas Boulevard Pittsburgh 8, Pa. Representatives in all Principal Cities PRODUCTS: Over 15,000 types, sizes and ratings of Chromalox electric heaters for Industry and Home. All heating elements are metal or alloy sheathed in metal for strength and corrosion resistance, fully insulated for safety. Edwin L. Wiegand Company 7672 Thomas Boulevard Pittsburgh 8, Pa. Representatives in all Principal Cities 147 CHROMALOX ELECTRIC UNIT VENTILATOR The Chromalox Electric Unit Ventilator has been specifically designed to meet the requirements for proper heating, venti lating and natural cooling of classrooms and similar rooms... wherever it is normal for many people to gather in a limited space. Fast response to a room's changing requirements... from heating ventilating to natural cooling, give the versatility required for these applications. ' Normally installed below, a window rill, a louvered opening through the wall permits the introduction of fresh outdoor air into the Chromalox Unit for proper ventilation and natural cooling. The unit can be supplied with automatic room tem perature controls. To eliminate discomfort from window downdraft, Chromalox Electric Baseboard Heaters are recommended on both rides of. the Chromalox Unit Ventilator extending the full window width. Units are available in 600, 750, 1000 and 1250 cfm Standard Air and up to 18.0 kw (61,500 Btu/hr) capacities. Bulletin D-6S. CHROMALOX ELECTRIC BASEBOARD RADIATORS Oloan, balanced radiant and convected heat supplied by rugged baseboard measuring only 8-% in. high and 2- in. deep. Lengths in standards of 1 ft with 100 watts, 2 ft with 300 watts, 5 ft with 800 watts, 8 ft with 1250 watts. Extremely easy to in stall. Heating element is all metal fully enclosed, flat strip type which is break-proof, moisture-proof and shock-proof. De signed for maintenance-free heating in homes, offices and public buildings. Bulletin 975. CHROMALOX AIR DUCT HEATERS For use in square or rectangular forced air ducts. Construction allows free-flow of forced air circulation. Finned elements pre sent maximum contact for fast heating and minimum air fric tion. For.room heating and process work. Ratings from 6 kw to 100 kw. Catalog 60. .. CHROMALOX ELECTRIC CABINET CONVECTOR HEATERS Chromalox Electric Cabinet Convector Heaters are completely enclosed, 18-gage metal casings, designed to give easy bottom access of air which is then heated by a bank of metal-sheathed strip heaters and convected outward and upward. Available in 6 in. deep free-standing models or semi-recessed models pro jecting 2y4 in. from wall surface. Heating capacities: 1, 2, 3 and 4 kw. Bulletin 976. CHROMALOX ELECTRIC FARINFRARED COMFORT HEATERS "Spot heating" for personal comfort without hearing entire' rooms or buildings. May be ceiling-, wall-, or floor-mounted as- best suited for various conditions. Heater housing is aluminum extrusion. Stainless steel grill .protects against accidental con tact. Length* from 24% in. to 85% in. Individual temperature control by Chromalox thermostat, or several, heaters may be controlled on automatic cycles with Chromalox input con troller. Bulletin F-1614- . . ' . CHROMALOX ELECTRIC PORTABLE COMFORT HEATERS Model shown is one of several available. Outputs range to 13,648 Btu's. Available with manual "on-off" switch or auto matic thermostat. Swivel stand adapts for wall or ceiling mount ing. Bulletin 975. CHROMALOX ELECTRIC FORCED-AIR WALL HEATERS Smooth molded contours of heavy-gage steel form the front grille. Recessed section contains a quiet, fully-enclosed motor and dustproof fan. Metal sheathed Fintube element nd fan ' are controlled by manual on-off switch. Variable temperature control knob for setting built-in thermostat. 1500 to 4000 watts for 240 a-c supply for game rooms, living rooms, motels, re ception rooms, etc. Bulletin 975. CHROMALOX ELECTRIC CIRCULATION HEATERS Circulation Heaters heat fluids in convection or forced heating systems; for washrooms, laundries, dishwashers, central heating systems, superheating and drying steam, preheating fuel oils and heat transfer fluids, gases. Temperature to 750F. Catalog 60. CHROMALOX FAR-INFRARED UNITS , Far-Infrared Radiant Heat for hearing, drying, baking, dehy drating, etc. Compact pre-engineered panels, heaters and lamps s can be made into banks, tunnels, ovens. All-metal construction' protects against breakage, splashing; high safety against shock hazards. Catalog 60. CHROMALOX ELECTRIC.HIGH VOLUME HEATERS . For hearing of larger areas or as central heating system. Ratings from 15 to 40 kw. Twin centrifugal fans, driven by a 3-phase motor, draw air into unit *nd across Chromalox Finstrip Heaters. Air deflectors furnished for each outlet to discharge warmed air slightly downward. May bfe-connected to ducts of conventional central system when required. Fans may also be used for summer cooling. Catalog 60. . 4965  148 Air Conditioning Date WESIX ELECTRIC HEATER COMPANY 390 First Street San Francisco 5, California Chicago Dallas Denver Los Angeles New York Detroit Portland Huntsville Seattle . Complete Line of Electrical Air and Liquid Heating Equipment for Residential, Commercial & Industrial Applications BASEBOARD PERIMETER PANELS with monofin element available in standard 32 in. and 48 in. lengths for simple, inexpensive installation without special tools or metal cutting. 250 watts (853 Btu) per linear.foot. Control section (thermostat and switch), Air-conditioning Supply Section and Receptacle Section, each 6 in. long. Comer section, hood and end pieces available. Approved by- UL. ' AUTOMATIC ELECTRIC BRACKET TYPE HEATER for commercial, institutional or industrial applications, these units are available in a large range of sizes and types including explosion-proof models for use In Class I, Group C and D locations. Approved by UL. AUTOMATIC ELECTRIC WALL FURNACE sizes range from one to eight kilowatts for use in domestic and commercial installations.- Available in radiantconvection (model illustrated), convector or blower type (5000 watt maximum). Approved by UL. DUCT HEATERS utilizing either Wesix "dust free" or conventional. transverse fin elements, these units may be ordered from a wide variety of self contained, standard units, or built to order. Units available com plete with sensitive integral overtemperature control. LOAD REGULATORS control electric hearing ca pacity automatically by switching voltage supply from 240 volts to 120 volts by means of outdoor thermo static control. Controls heating loads up to 24 kw. Approved by UL. INDUSTRIAL UNIT HEATERS--BLOWER TYPE for horizontal or vertical mounting either as suspended unit heaters or duct system use in standard sizes to 60 kw. Larger sizes or models for special applications on order. Approved by UL. QUIET AUTOMATIC SWITCH, a motor operated contactor for resistance loads to 24 kw, 1$ or 40 kw 34, 240 volts and 33 kw 14 or 55 kw 34, 480 volts. Actuated by SPDT switch or thermostat. Available with sequence action for control from single switch of two or more contactors. Approved by TIL. COMMERCIAL UNIT HEATERS--AXIAL FLOW sizes from 3 to 40 kw for ceiling or pedestal mount. Feature Wesix longitudinal fin, "dust free" inclosed heating elements. Approved by UL. HEAVY DUTY WALL THERMOSTAT AND SWITCH for control of electric heating apparatus di rectly up to 25 amp, this unit includes a lockout switch double pole in the "off" position. Thermostatic action is bi-metallic, sensitive to plus or minus 1 degree F. Fits standard wall box mounted vertically. Case color: Ivory. Approved by UL. Air Conditioning and Heating Piping VibmiM md N*be 149 THE AMERICAN BRASS COMPANY AMERICAN METAL HOSE DIVISION WATERBURY 20, CONNECTICUT Specify "AMERICAN" VIBRATION ELIMINATORS Stocked by leading wholesalers AN ANACONDA PRODUCT AMERICAN VIBRATION ELIMINATORS for the important job of CONVEYING REFRIGERANTS and minimizing transfer of VIBRATION and NOISE STANDARD SIZES Standard copper tube "slip-fittings" welded on both ends. Suitable for any industrial or domestic air conditioning or ' refrigeration unit or any general piping encountering vibra tion. V. E. DATA TABLE I TO FIT COPPER TUBE FTlpemxiWnie Actual OD Nominal u>. V, Me Vt ft H % A ^6 ft ft ft % ft ft v ft ft 3/ ft H % y % 11 i% i*/ ift i% ift ift 2ft 2 2 2% 2ft m 3% 3 3% 3% 3 3ft 4ft 4 4 sy8 5 6ft 6 5 6 ft 8 8 FEMALE ENDS Part No. H 3618F * 7 1418F 5614F 7ft 8ft 3838F 9 1212F I258F 9ft 10 .3458F lift 3434F lift 1010F 13 5454F 6464F aft 17 2020F 20 5252F 24 3030F 27 7272F 32 4040F 33 5050F 41 6060F 49 808QF 62 U. L. No. OB Ferrule* W-36 W-14 W-56 W-38 W-12 W-12 W-34 W-34 W-10 W-54 W-64 W-20 W-52 W~30 W-72 -- -- -- -- Listed* by Underwriters' Laboratories, Inc. in copper tube sizes through 3% in. O.D. ID. of Copper Tube Ends for Depth "K" meets ASA Std. B16.18--1950 and ASA BI6.22--1951. in. ID. and larger are double-braided with tin bronze wire for extra strength and protection. Sizes above 3 in. ID. are soldered under the ferrules after welding. Copper Tube Ends on sizes above 3 in. are commercial parts and "E" and "H" may exceed tolerances shown. "G" Tolerance: plus or Wft.QCO STCIMa-jBaRxOsNsZErCTeUxBaINcGe fc i V. E. DATA TABLE H FTlueLbuDibn-le* Me ft Me ft ft ft ft ft 1 l*/4 1ft 2 2ft 3 3ft 4 5 6 8 fte ft ft ft 1 1 IKe Me Me 1ft 9ft 2ft 3ft 4ft 4ft 3ft 8ft 7ft 9ft B ft ft `Me Me Ifte 1ftfi lft> 1ftR 1ft 2 2ft 3 3ft 4ft 5 5ft 7 8 10 . ft ft ft ft Me Ke Me ft Me Me 1 iMe 1ft 2 2 2 2 2 E ft ft ft ft ft 1 ift ift ift ift 2 2ft 3 3ft 4 ift 5ft 8ft 7 c 6 8ft 7 7ft 8 8 9 9 10 nft * 13 15 18 20 24 24 30 . 36 48 minus in. for sizes through 4 in. ID. Above 4 in. ID.: plus or minus M in- VE's are sealed in polyethylene envelopes for internal and external protection. Also available with male ends. Write for specifications. Underwriters' Laboratories (UL) number on ferrule may appear with prefix "M" instead of "W." Neoprene latex covered VE's are available for use when danger exists from condensed moisture on the outside of the unit  150 Air Conditioning and Heating Piping * The American Brass Company Waterbury 20, Conn. District Offices in Principal Cities IN CANADA: Anaconda American Brass Limited, New Toronto, Ontario PRODUCTS--Anaconda Phosphorized Copper Tubes and Fittings; Anaconda "85" Red Brass Pipe; Ererdur Metal for storage heaters, storage tanks, ducts and air-conditioning equipment Anaconda Types K and L Phosphorized Copper Tubes, assembled with solder-joint Fittings, offer an unusual combination of advantages for hot-water and low-pressure-steam heating systems, including radiant panels. These advantages may be summarized briefly as follows: Low Friction Loss--Smooth, nonrusting inside sur faces of copper tubes do not become rough, and offer an unchanging low resistance to flow. Ease of Installation--The flexibility of copper tubes simplifies connections which would be awkward and expensive with rigid pipe, and solder-joint fittings can be installed in restricted places where the use of a wrench would be impossible. They meet the requirements for these types of tubes in Federal Specification WW-T-799a and ASTM Speci fication B88, when so specified. Type K, the heavier, is recommended for heating lines and general piping. Heat for this basement game room will be provided by Vi in. PG's imbedded in the concrete. Troublesome hand bending and resulting sags and dips that increase friction loss are elimi nated with pre-fonned PG's. Vi in. for floors). They can be contracted or expanded by hand to obtain a range of C-C spacings. PublicationC-6 describes economies of PG's, gives simplified design suggestions and short-cuts to calculating heat output. Anaconda Copper Tubes, in standard sizes, are fur nished soft in 60- and 100-ft coils; also hard and soft in 20-ft straight lengths. Anaconda Type M Copper Tube is furnished hard drawn in 20-ft straight lengths in nominal sizes from VA in. to 12 in. for drainage lines in certain types of air-conditioning installations. This tube has a thinner wall than Types K and L and provides economies in weight and cost when used in the larger sizes. Type M tube is assembled with wrought-copper or cast-brass solder-joint fittings. * PC's (Pre-Formed Panel Grids) Anaconda Panel Grids are machine-formed radiant-heating coils of Type L copper tube, supplied in two standard panel sizes and two nominal diameters (% in. for ceilings, * Trademark Reg. U. S. Pat. Off. CUSTOM-MADE CAPILLARY TUBES Anaconda Custom-Made Capillary Tubes, for re strictor purposes, are made to specific mutually agreed-upon airflow limits. These limits alone are the basis for production. Initial shipments contain Master Reference Sample Tubes with labels giving maximum and minimum flow capacities agreed upon. Duplicate Master Samples are kept in the mill files. Every subsequent shipment of tubes will be made to the limits of the Master Samples. All Anaconda Restrictor Tubes are plug-drawn to finish to provide a smooth, round inside bore'. Each length is chambered at both ends, thoroughly washed and dried, given a final air-flow test, and carefully paper-wrapped in a bundle. (Top) A cross-section of an Anaamda Copper Restrictor tube, .081 in. OD x .031 in.,ID, magnified 10X. Note the roundness of the bore. (Bottom) Section of a photo micrograph at 200X magnifi cation to show smoothness of the bore. The American Brass Company 151 REFRIGERATION TURING Anaconda Dehydrated Copper Refrigeration Tubes are manufactured in accordance with ASTM Specifi cation B280 in all standard sizes up to and including Ya in. O.D., in 50-foot coils. The tubes are sealed im mediately after annealing and dehydrating. VIBRATION ELIMINATORS American Vibration Eliminators--Compressor vi bration and noise are muffled in a line equipped with an American Vibration Eliminator. The corrugated tinbronze tubing is seamless. Copper ferrules and tube ends are braze welded. Ea,ch unit is pressure-tested under water, is spotlessly clean and dry, and is packed in a polyethylene envelope. ANACONDA "85" RED BRASS PIPE Anaconda "85" Red Brass Pipe, in standard pipe sizes, is considered the highest quality corrosion-re sistant pipe commercially obtainable at a moderate price, and is the material preferred by many engineers for steam condensate return lines. EVERDUR* Everdur Metal is the original copper-silicon alloy group. These high-strength, highly corrosion-resistant engineering alloys are manufactured by The American Brass Company in five standard compositions and in practically all commercial forms. In addition to their nonrusting properties and high strength, Everdur alloys possess many qualities not usually found in metals of this character. They are unusually resistant to general atmospheric conditions and other normally corrosive factors. Everdur alloys have excellent machining and working characteristics, and can be fabricated into a variety of forms and shapes. Everdur alloys are available for oxyacetylene, carbon-arc and inert-gas arc welding. Everdur Tanks--Everdur copper-silicon alloy is an ideal material for durable, nonrusting water tanks of every description--from domestic range boilers to large storage heaters for hotels, laundries, hospitals, textile plants, schools or breweries. Everdur is made in all commercial shapes, including annealed tank plates which have physical properties as given in ASTM Specification B96. Minimum specification requirements for hot-rolledand-annealed tank plates are: Tensile Strength, 50,000 psi.; Yield Strength (at 0.5 percent elongation under load) 18,000 psi.; Elongation, 40 percent in 2 inches. Welds made with annealed Everdur tank plates meet the requirements for construction in the ASME Boiler* and Pressure Vessel Code. ' For additional data and names of fabricators, ad- . dress our nearest District Sales Office. EVERDUR FOR AIR-CONDITIONING EQUIPMENT Because of its strength and welding properties, Ever dur may often be substituted for steel and fabricated by substantially the same methods, with much the same equipment as steel. Everdur metal has been used with marked success for fans, blowers, ducts, humidifiers, cast and wrought parts of other equipment items subject to corrosive in fluences. EVERDUR LITERATURE * Descriptive literature containing much pertinent tabular data will be sent on request. Trademark Reg. (J. S. Pat. Off. RESTRICTOR TUBE FORMED TUBE PARTS . HARD COPPER TUBE CUT TO LENGTH COPPER TUBE IN COILS AND STRAIGHT LENGTHS PRE-FORMED RADIANT PANEL GRIDS FITTINGS FOR TYPES K AND L TUBES VI BRATION ELIMINATORS FLEXIBLE REFRIGERATION TUBING CONDUIT DIE PRESSED FORGINGS COPPER, BRASS. BRONZE IN SHEETS. WIRE, RODS, TUBES AND SPECIAL SHAPES  152 Air Conditioning aruf Heating Piping WOLVERINE TUBE CAU1MKT ft HtCUh IMC. Saatbfiald Raad fail, Michigan d Tuftiaf *M Cnrudcd Atuffiaun SftaftM PLANTS IN DETROIT, MICHIGAN AND DECATUR, ALABAMA. SALES OFFICES IN PRINCIPAL CITIES. Tab* o4 Flttiafi 153 WOLVERINE TUBE CALUMET ft HECLA. INC. 17286 Se*lb(tld Road A II b Park, Michigan PLANTS IN DETROIT, MICHIGAN AND DECATUR, ALABAMA. SALES OFFICES IN PRINCIPAL CITIES. WOLVERINE ROLL-O-TUBE .., copper water tube in a round carton that rolls Wolverine Roll-0-Tube represents a new packaging concept for rolls of copper water and refrigeration tube. Roll-O-Tube for example, simplifies tube handling. It can be rolled, like a hoop, to job site or storage. A con venient center hole makes carrying easy. By holding the tube at one end and unreeling the required length, Roll-O-Tube functions as a reel. Also of importance to users is the fact that unused tube remains in the Roll- 0-Tube carton protected against damage and dirt un til needed again. Large easy-to-read print and color coding on the opening tape make identification fast and sure. WOLVERINE VERSATUBE* Aluminum Utility Tube used for air lines, connecting lines for pumps, stoves, oil burners, etc. Packaged in master cartons. Available in from Vs in. O.D. to VS in. O.D. WOLVERINE COPPER WATER TUBE Wolverine copper water tube is available in three types: Type K---in straight lengths and rolls--is recom- , mended for general plumbing where severe service con ditions may be encountered as well as for heating, gas, steam, and oil lines. It is also used for underground service. It is available in nominal sizes from Y\ in. through 6 in. . Type L--in straight lengths and rolls--is recommended for. general plumbing involving less severe conditions and for internal applications for heating, gas, steam and oil lines. It is available in nominal sizes from % in. through 6 in. Type M and Type DWV--available in straight lengths only--are ideally suited for DWV (drainage, waste, vent) installations and for other non-pressure applica tions where soldered fittings only are used. Type M is available in nominal sizes from H in. through 6 in.-- Type DWV, 1V4 in. through 4 in. Wolverine also manu factures standard and extra heavy S.P.S. pipe in cop per and red brass. Pipe is available in standard lengths of 12 ft and 20 ft. Sizes range from Vs in. through 3 in. Standard, industry-approved color coding identifies the various types of tube. WOLVERINE COPPER REFRIGERATION TUBE Wolverine copper refrigeration tube is well known throughout industry. It, too, is available in straight lengths and rolls. La roll form, Wolverine copper re frigeration tube comes packaged in the convenient Roll- O-Tube carton. Wolverine refrigeration tube is dehy drated, has a clean, mirror-bright inside surface and is consistent in quality and temper. As a further service to its customers, Wolverine refrigeration tube is pro vided with unique plastic plugs for positive end-seal ing. These plugs are removable and may be used again and again; because their O.D. is no larger than that of the tube there is no need for removing the plug when threading through partitions. ' . * Patent Applied For. TUBE SEAL WOLVERINE CAPILATOR Wolverine copper Capilator tube is designed for pre cision control in the metering of gases, liquids or air. Tiny, plug-drawn Capilator has a smooth, mirrorbright bore held to exceptionally close limits. It is avail able in sizes from .026" to .090" inside diameter. Capilator is washed, deburred, flow-tested and its ends are paper wrapped to insure absolute cleanliness. For general metering or control purposes, Wolverine-also manufactures rigidly quality controlled small diameter copper tubing, .062" O.D. and larger. FABRICATED TUBULAR PARTS Through its Copperf and Aluminum! Spun End Proc esses Wolverine is able to produce one-piece, tubular shaped parts (below) with a wide variety of contours and end treatments in one fast, economical operation. Other Wolverine fabrication techniques include finning, bending (such as the hairpin return bend at left above), coiling, flaring, expanding--to name but a few. WOLVERINE TRUFIN* Wolverine Trufin is an extended surface tube with fins extruded directly from the tube wall. Because of this, Trufin provides increased.-heat transfer surface--ex tracts more Btu's per foot of tube. Trufin's integral fins also resist vibration, temperature changes, and fluctu ating pressures. Trufin is available in five different types in a wide range of sizes, alloys, and fin spacings-- in copper, aluminum, and seamless steel. Illustrate! is Trufin Type H/R--a high finned tube ideally suited for air cooled heat transfer operations. ALUMINUM TUBE AND SHAPES Wolverine produces strong, lightweight aluminum tube--plain or finned--drawn or extruded--in a wide variety of sizes in popular alloys. Wolverine extruded aluminum shapes are rigidly quality controlled to meet customer specifications--can help save machining and assembly time and reduce material requirements. FIELD ENGINEERING SERVICE - For the convenience of our customers Wolverine maintains its Field Engineering Service. Highly skilled tubing technicians are ready at all times to help you solve problems in design, corrosion or fabrication. t Patented Process RE 22465. | Process Patent Applied For.  154 Air Conditioning and Heating Piping Copper & Brass Research Association 420 Lexington Avenue, New York 17, N. Y. The two most common types of solder used in joining copper tube are 50-50 tin-lead solder and 95-5 tin-antimony solder. 50-50 solder is generally used for moderate pressures with tem peratures up to 250 P. For all temperatures up to250 F where higher strengths are required, the 95-5 solder should be used. In general, 95-5 solder melts at a higher temperature than does 50-50, has less of a pasty range, and is therefore somewhat more difficult to handle, particularly for a vertical joint to be filled upward. . The fluxes best suited to the 50-50 and 95-5 solders are in paste . form and consist of a petrolatum-base, impregnated with zinc and ammonium chlorides. It should not be the function of the flux to clean the copper, but assuming that the copper has been cleaocd the flux may be reasonably expected to remove resi dues of Oxide, in addition to protecting the surfaces from oxida tion during the heating process. The flux also floats out the remaining oxides ahead of the molten solder and promotes wetting action of the solder. In general, paste-type fluxes are recommended rather than liquid fluxes. 1. cleaning tube end 2. cleaning fitting socket 3. fluxing tube end 4. fluxing fitting socket It cannot be too strongly emphasized that for strong, tight, long lasting joints, thorough cleaning of the tube surface and the inside of the cup of the fitting is of utmost importance. Pretinning is not necessary and generally is not recommended if the metal is properly cleaned and fluxed. ' Fittings that are oversize will result in a loose fit. The capillary action is dependent on a fairly tight fit although a certain amount of looseness can be tolerated. Looseness is more apt to cause difficulties in working with the larger size copper tube, especially for horizontal joints where an oversize fitting may allow the tube to rest directly on the socket, resulting in a double width space at the top. Wherever possible, such joints should be made up in a verti cal position,* before assembly. For best results always use fittings conforming to accepted standards. Making up a joint There are six simple steps that, when followed, will result in a well-made joint. These steps should be taken after first measuring the tube to proper length so that it will run the full length of the socket of the fitting, cutting the tube end squarely and removal of all small burrs. ' 1. Clean tube end and socket of fitting. 3. Apply flux to the clean 4. Apply heat and solder. 5. Remove residual solder and flux. areas. 3. Assemble. . 6. Allow joint to cool. Safe Strength of Soldered Joints Pressure Ratings 7. applying solder 8. removing surplus solder and flux **ASTM B32, Alley grade 50A tlttdudiog refrigerants and other netxorrojive liquid* ond gates ttASTM B260, Brazing Filler Metal . . Air System Equipment ^ 155 Air Devices Inc. Air Diffusers Registers Grilles Exhausters Air Filters High Velocity Mixing Boxes Punkah Louvres Filter Holding Frames * Industrial Furnaces 185 Madison Ave. New York 16, N. Y. LI P1I Q| L--J I I U 11 ill It Agents in All Principal Cities AGITAIR AIR FILTERS Type FMft HIGH VELOCITY - ALL METAL PERMANENT ' CLEANABLE HOW IT WORKS High turbulence of many finely divided air streams is-the keynote of Type FM air filters. The media divides the air into countless fine streams and throws those streams .into violent cyclonic turbulence against countless viscous-coated "wiping surfaces" which virtually scrub the air clean by catching and holding the dirt. HIGH VELOCITY The Agitair FM Filter is designed to perform at highest efficiency at an approach velocity of 432 fpm--or 1200 cfm through a 20 x 20.in. filter panel. 1/3 LESS SPACE REQUIRED The ability of the FM to filter, with greater efficiency) 50 percent more air at the high velocity of 432 fpm reduces the number of filter panels required. Now TWO FM's will do the work of THREE ordinary filters . . . H less space required ... fewer units to be installed ... fewer units to be serviced ... overall installation and maintenance costs reduced to a mini mum. * HIGH EFFICIENCY At the recommended velocities, the Agitair FM has a high dust arresting efficiency, which increases as the dust load is applied. LOWER RESISTANCE The sustained low resistance of the Agitair FM means sus tained peak volume of air for longer periods of time ... no loss in air volume ... no danger of unloading . . . clean filtered air at all times. ' HIGHER DUST HOLDING CAPACITY Employing a new formula for air filtration the new Agitair FM holds more dirt, from two to six times as much as ordinary 2 in. permanent, cleanable filters. No early clogging of air pass ages . . . less frequent servicing . . . lower maintenance cost. TWO TYPES OF HOLDING FRAMES Individual type: Designed and constructed for easy han dling in single unit installations, and to facilitate "on the job" assembly, into a multiple unit bank. Pre-Fabricated Type: Made of heavy gage steel and delivered completely knocked down. They can be quickly and easily bolted together to form a sturdy panel bank. . . GREASE FILTERS Strong Expanded Metal Media recommended for use ia kitchens where grease-ladened air is a fire hazard and a mainte nance problem. Prevent grease from entering exhaust ducts, eliminate frequent duct cleaning, protect fans, greatly reduce fire hazard, and help maintain good ventilation. AGITAIR WIND-ACTUATED EXHAUSTERS Type CNO Provide proper ventilation regardless of wind direction, and with positive elimination of down-draft. Functions at peak efficiency at average low wind velocities..Will not restrict the exhaust of air or gases when there ia no movement of outdoor air across the head. . *.  156 Air System Equipment Air FOun AIR FILTER CORPORATION 4554G West Woolworth Ave. Milwaukee 18, Wis. Douglas Engineering Co., Ltd. Canadian Representative Toronto, Ont. /1/ffSA# ' fcq. U. S. trt. 06 AIR FILTERS GREASE FILTERS Permanent--Cleanable VIRO-CRIMP FILTER (Type W) Pit: No. 2,653,676 A designed high velocity filter media, viscous type. Constructed of horizontal layers of galvanised wire mesh as suring a large filter-area with no appreciable pressure drop. Designed for velocities of 300-600 fpm at minimum resistance. Viro-Crimp edges are hemmed, an important safety feature that provides a smooth media surface. . Type W, Airsan High Velocity Air Filter is of all galvanised metal construction throughout. Drain slots provided to hasten drying and aid in cleaning. Available in all standard and special sizes (3 in. and 4 in.). Bulletin W802. AIR FILTERS - Low Velocity . (Type AF-1, AF-2) Domestic Industrial Commercial Expanded metal face plate acts as a lint arrestor to provide easier cleaning and servicing. It distributes air evenly over entire filter area providing high filtering efficiency and dust holding capacity with low resistance. Media is viscous type, permanent, cleanable, and is constructed of multiple layers of galvanized wire mesh. Galvanized steel frames *nd drain riots for quicker easier cleaning. Available in standard 1 in. and 2 in. thickness. Bulletin SOt. Also HEAVY DUTY filters (Type AD-2, AD-4) for industrial and special applications-- 2 in. to 4 in. thickness. Bulletin 409. For Air and Grease Filters. Features include positive snap locks, fire resistant felt seals etc. Particularly flexible to any type of installation of fiat or "V" banks. Easily built up to any height or width by progressive addition of Airsan Filter Retainers. Available in 2 or 4 in. rizes. Bulletin L60S. Permanent cleanable type Airsan Grease Filters are specially designed for range canopies, galleys, and kitchens.' Removes grease at source, reduces fire hazard in evhanst ducts, and prolongs life of fans, motors. Assemblies for mount ing on ceiling or wall, single or multiple units--include bolding frames, Supporting angles and end seals. Bulletin L604. Write AIR FILTER Corp. for Complete Bulletins AIR FILTER CORPORATION-4554G W. WOOLWORTH AVE. MILWAUKEE 18, WIS. Air System Equipment Air Faun ciww 157 'MASS CORPORATION 25000 Miles Rd., Cleveland 28, Ohio THE FILTER ENGINEERS Representatives in all principal cities Because filtering air is still an art rather than an absolute science, proven ex perience itself is even more important in this field than in other technical areas.. We at Air-Maze have specialized entirely in the art of filtration for well over 30 years. As a result, there are few filtering problems that we have not encountered during this time. Through first hand ex perience, we have learned that what not to do is a highly important factor in sue . cessfully engineering a filter for a par ticular job. There is a saying in the filter business that, "In most cases one never knows he has the wrong filter until it's too late". Consequently,-as a buyer or specifier of filters, our years of proven experience, we believe, are invaluable to you. The prime function of our application engineers is to guide you in selecting the - right filter . . . even though it mpuna suggesting an item we do not make, as is sometimes the case. By experience, we recognize that future business depends on your confidence in us. So we endeavor to justify your complete confidence in every recommendation that Air-Maze makes. A fully staffed organisation, backed by adequate plant facilities with a well- equipped testing laboratory, have helped Air-Maze become one of the largest filter manufacturers in the country. Send for catalog sheets on specific products. General catalog also available on request. J... ELECTROMAZE ELEC TRONIC AIR FILTER The Electromaze 2-stage electronic air cleaner performs an air cleaning function using the electrostatic phenomenon that no other commercial device can do. It is one of the two practical methods ' for removing particles of sub-micronic size. These particles include smoke, fumes, and carbonaceous matter which authorities agree is the principal cause of discoloration. The electronic air cleaner does this air cleaning job with' extremely low pres sure loss and high dirt-holdingcapacity. For all practical purposes the pressure . drop is so low as to be negligible. Its operating costs and maintenance are unusually low. Electromaze employs high-voltage direct current to ionize the air (and entrained dirt contaminant therein) by means of a corona discharge. Ionized particles are readily collected on plates having op posite positive and negative charges on alternate plates. AIR FILTER PANELS Available in metal washable, viscous impingement types,- and dry dis posable types. Dry filters also avail able with washable 6trainer-type . filter element. Has semi or completely automatic verti'cal spray washing system. Removes particles as small as 0.1 micron diameter, has rated efficiency over 95 percent, as tested by the National Bureau of Stand* ards' Discoloration Method. AUTOMAZE AUTOMATIC AIR FILTER Where continuous operation without servicing is required, the Automaze . "pulse action" automatic self-clean ing filter should be used. It combines a double filter panel curtain with a positive effective panel cleaning ac tion to provide a better viscous im pingement air filtration with a mini mum of maintenance. New self contained drive mechanism and unitized control system simplifies installation. Standard Automaze fil ter media is satisfactory for most installations, but other media types are available for special applications. ACCESSORIES . Cleaning tanks, holding frames, complete assemblies for range cano pies, viscous adhesive coatings, spray guns, etc., are available for complete installation and service requirements.  158 Air System Equipment American Air Filter Company, Inc. 673 Central Avenue, Louisville 8, Ky. AKEUCAN All FiLTea of Canada, Ltd., Montoal. P. Q. Air Fibers American Air Filter Company, Inc. 673 Central Avenue, Louisville 8, Ky. Ameucan An Piltex of Canada, Ltd., Montbeal, P. Q. 159 THE COMPANY; The American Air Filter Company, Inc., is recognized internationally as an authority on air filtration and dust control. In 30 years, its leadership and scientific "know how" have been responsible for installa tions of AAF equipment in every industrialized part of the world. Because its continuous research, high engineering standards and exclusive specialization have been consist ently maintained, AAF equipment is used by leading com panies in nearly every .industry and is specified by leading architects and engineers for use in commercial and indus trial air conditioning. The American Air Filter Company, Inc., manufactures a complete line of air filtering and dust control equipment. . A few representative types are shown here. AAFs years of experience and the scope of its knowledge dealing with the elimination of air-borne particles in every form insures maximum' efficiency in application, design, manufacture and installation . . . with a minimum of field engineering. Write AAF on all problems of air filtration and dust control, or its Herman Nelson Division on heating or ventilating problems. AAF AIR CLEANING PRODUCTS Electro-Matic Self-Cleaning Electronic Precipitator--The Electro-Malic Precipitator is an automatic electronic pre cipitator combining advanced principles of electronic air cleaning with a special self-cleaning principle, it eliminates the necessity of shutting down the filter for manual clean ing, minimiTFis the need for personal attention and permits continuous high-efficiency operation. It also allows the Electro-Matic filter to be built in standardized self-con tained sections, easy to install and with all exposed parts of the filter casing electrically grounded for the protection of operating personnel. Send for Bulletin No. 250. ROM-O-MATIC Renewable Media Filter --An automatic air filter featuring a low cost, renewable media filtering curtain of bonded glass fibers supplied in convenient roil form. The media, mounted at top of filter, moves down the face of the ROLL-O-MATIC and is re-roUed on a driven spool at bottom. Introduction of clean material to maintain :desired operating resistance is controlled by an automatic time switch. ROLL-O-MATIC's maintenance-free opera tion provides continuous, high efficiency cleaning at less than half the operating cost of a disposable type filter of equal capacity. Send for Bulletin 248. The Electro-Cell is a stationary plate-type electronic precip itator available in both conventional and high-velocity deigns for application on a wide range of dirt concentrations. Cell construction assures simplified installation and ease of main tenance. Collector assemblies may be removed for individual cleaning--washed in place manually--or, with the addition of Type "H" Washer, cleaned automatically by traveling water sprays. Write for Bulletin No. 252. Electro-PL--A special dry-type electronic air .filter with charged Airmat collector element which combines air filtra tion and electronic precipitation in a single unit. Gives inter mediate efficiency at lower cost, when the need for super dean air is not indicated. However, it has twice the efficiency of uncharged dry-type filters-Available in Straight Bank or "V" arrangement to meet virtually any space or capacity requirement Send for Engineering Bulletin No. 257. AMER-glas Replaceable Unit Filters. A new viscous impinge ment type for eliminating atmospheric dust from forced air beating systems. The highly efficient filtering media consists of continuous, curled and interlaced, extremely fine glass fil aments, bonded with thermoplastic to form a thick resilient pad. The pad is sprayed with a special Viscosine and placed in a fiberboard casing between perforated metal grilles. The AMER-glas is nonflammable, sanitary and odorless and the Viscosine remains in a fluid-jell state for the life of the filter. Available in 15 sizes. Write for Bulletin No. 211-A. Airmat Type PL-24--Airmat filters use standard Airmat me dium, renewable after collecting dust load. Used both for comfort and industrial air conditioning. Available with unit frames to be set up to meet any capacity requirement or space condition. Send for Bulletin No. 230. Maid-Duty Automatic Filter provides outstanding features of performance and design and will accommodate either ar mored screen panels or die stamped louvre panels available in three types. Offers advantage of uniformly constant air supply, fixed operating resistance and automatic operation. Ideal for ventilation and air conditioning service. Available in any size or capadty. Send for Bulletin No. 241-A. Type HV-2 Filter: A high capacity, low-resistance unit de signed for velocities up to 500 fpm. Special pyramid pocket media design eliminates through-air passages and gives uni formly high efficiency over wide range of air velocities. HV-2 has large dust capacity, long life, and decided advantages where space is limited. Available in three designs. Write for Engineering Bulletin No. 203. AMER-glas Disposable Filler I  160 Air System Equipment American Air Filter Company, Inc. 673 Central Avenue, Louisville 8, Ky. Ameucam Aik Pn.m op Canada, Lt,, Monikeal, P. Q. AAF DUST CONTROL EQUIPMENT AD AAF Dost Control equipment--dynamic precipitator*, by* drostatic precipitator*, dry centrifugals and fabric arresters-- combine the functions of exhausting, separating and storing dust in one simple, compact, self-contained unit. All have these basic design features: (1) small space requirements, (2) maintained performance over a wide range of operating conditions, (3) constant exhaust volume, and (4) high col lection efficiency. Available in a wide variety of types and sizes, AAF equipment has a proven record of economy and efficiency covering thousands of production line and indi vidual applications. Write for profusely illustrated 35-page application and Engineering Bulletin No. 274-A. Type D ROTO-CLONE --A dy namic precipitator designed for dry collection of granular indus trial process dust Combines func tions of exhauster, dust separator and storage facilities in one com pact unit High collection effi ciency remains constant over entire pressure volume range. Adapted for individual unit or central system use. Capacities -- from 100 to 15,000 cfm. Write lot Bulletin No. 274. Type 0 ROTO-CLONE Type W ROTO-CLONE offers high dust separation efficiency where extreme fines and heavy ' dust loads are involved. Combines dynamic precipitation with inte gral water sprays. Delivers a con stant air volume and collects dust as a sludge. Compact design makes for easy, low-cost installation. Ca pacities from 1,000 to 50,000 cfm. Write for Bulletin No. 274. Typs W ROTO-CLONE Type N ROTO-CLONE is ahydro static collector, with induced water scrubber. Requires min imum space--easy to install. No moving parts, spray nozzles or pumps. Completely self-contained with dust discharged as a sludge. Capacities--from 1,000 to 50,000 cfm. Write for Bulletin No. 277. AMERjet--A reverse jet type fabric arrester offering high col lection efficiency, constant pres sure drop (constant air volume), compact design and continuous operation. Other features are (1) unique method for pressure air supply, (2) rugged mechanism for dislodging collected material with high pressure air jets and (3) ven turi-shaped inlet for dust-laden air which extends life of cloth. Avail able in range of capacities. Bul letin No. 279. . AMERdone --A dry centrifugal dust collector designed to handle large exhaust volumes containing dust in high concentrations. Unit requires small space due to com pact design and high cleaning ca pacity of the AMERdone tubes. Abrasion resistant construction featured throughout. Collection efficiency remains practically con stant over wide range of exhaust volumes. Available in wide range of capacities. Write for- Bulletin No. 291. AMERjet AMERdoo* Air System Equipment Air FUlcr* asi Cl.mrr* BARNEBEY-CHENEY Cassady at Eighth, Columbus 19, Ohio Los Angeles San Antonio St Johns, Quebec Barnebey Cheney Activated charcoal purification equipment Bamebey-Cheoey manufactures activated charcoal and purification equipment for air, water and chemical products. Used in air purification, AC eaves on heating-cooling costs by permitting recirculation of air. AC adsorbs odors, irritating vapors, smoke and smog. Completely revitalizes stale or stuffy air. 161 FilterFokl adsorber* Pleated filter with V4 in. bed of charcoal. Installed in mul tiples, these cells give large air handling capacity in a small space. Each cell will handle up to ljOOO cfm at 02 wg. Heavy guage steel frames take rough treatment (stainless frames available). Five types available. Wall anil Flush mounted circulator for semi-light duty use. Contains centrifugal fan, charcoal filter, and dust filter. Steel cover plate furnished with prime coat. Designed to fit between studding. Capac ity: 150 cfm. ' Cabinet circulator* Complete units contain panel adsorbers, dust filter, cen trifugal blower, and motor assembly. They are fully assembled, ready to plug in. Designed for long service and quiet operation 24 hours a day. They will purify up to 12,000 cubic feet of space. Heavy duty units are available for warehouse or industrial operation. These may be ceiling mounted or portable. Canister adsorber* Cylindrical perfo rated metal with H in. to V* in. bed of charcoal. Use these for small jobs and for expansion of <*rgting installations. They are mounted in manifold plates in multiples, depending on cfm, and are in terchangeable with other types of can isters. Four models. Canister circulators Complete unit con tains removable canister and blowermotor assembly. Designed for small rooms ant^ enclosed areas. Four models, with capacities from 15 to 120 cfm. Either floor stands or wall mounting available. Panel adsorbers Flat perforated metal cell with 1 in. bed of activated charcoal.. Use it when the contaminant load is heavy and you want long service life. Frame assemblies and panels are avail able for any air flow. Capacities up to 180 cfm at 03 wg. Three models. - Other products and services Dispos able charcoal filters in paperboard frames are available for use in air conditioners, forced air furnaces, and ventilating sys tems. Breeze circulators are' attractive . units for homes, offices, clubs. '- Bamebey-Cheney's complete line of activated charcoals is available in bulk. Ask for free literature. 162 Air System Equipment FUlcn BURKE AND COMPANY 2902 Hyde Park Boulevard, Los Angeles 43, California TOTAL AIR DETENTION REPLACEABLE MEDIA AIR FILTERS GAS AND VAPOR ADSORBERS Roto Aire RMl-IR Series Impingement-Strainer Type Replaceable Media Air Filters with Integral Retainer. The Roto Aire RMl-IR Series impingement-strainer type replace able media air filter with integral retainer is the "advanced design" air filter which combines the filter holding device and the filter itself. It is comprised of a heavy gauge retaining frame which is faced with a sheet of 1' diamond, flattened, expanded steel and equipped with filter case centering dimples and spring loaded positive filter media case face-locking devices. The filter media case is likewise constructed of heavy gauge steel and is faced with a 4" mesh 12 gauge welded steel rad grid. The spring loaded posi tive filter media case face locks permit the installation of filters on any angle and press the filter case against the retainer so securely that by-pass of dirt laden air is eliminated. The filtering medium is glass fiber and consists of one filter pad (hat has a bulk thickness of 2* and one strainer mat that is .025" in thickness. Each medium is treated with Type 20] non-inflammable binder, and the 2" filter medium is treated with TCP (Tri-Cresyl Phosphate adhesive), the surface chemistry of which- is cationic. Roto Aire RM2-IR Series Impingement-Strainer Type Replaceable Media Air Filters with Integral Retainer .` Roto Aire RM2-IR Series air filters differ from the RMl-IR Series to the extent that the filter media case is 2" in depth.to accom modate three distinct types of filtering media namely large par ticle preload paper in addition to the media employed in the RMl-IR Scries. These media perform the various (unctions -of retaining airborne substances over the wide range from lint collec tion to retention of 0-5 micron particles. Greater economies in operation are to be realized because of their high dirt holding capacity and low face loading characteristics. Roto Aire G Series Impingement-Strainer Type Replaceable Media Air Filter with Integral Retainer The Roto Aire G Series air filter is comprised of a retainer, a gate lock grid and two types of fiber glass filter media that combine to form an integral filter cell. The-retainer consists of an "L" type welded frame that is faced with flattened expanded steel to form a case for the filtering medium. Clips for hinging and locking the grid are also provided in the retainer. The grid is fabricated from steel wire and shaped so that when opened it sets off to permit easy installation of replacement filter media. Like the Roto Aire I.R. Filter, the G Series filter may be installed at any angle, and the grid, when locked in place, presses the filter media against the retainer so securely that by-pass of dirt laden air is eliminated. The filtering medium is glass fiber and consists of one filter pa<f - that has a bulk thickness of 2" and one strainer mat that is .025' in thickness. - Roto Aire Gas and Vapor Adsorbers PARTIAL AIR DETENTION ROTO AIRE GAS AND VAPOR ADSORBERS increase comfort and physical efficiency because they purify air by removing noxious gases and vapors. The air purifying agent in Roto Aire Gas and Vapor Adsorbers is granular carbon that has been processed at high temperature to expel hydrocarbonic impurities and increase its porosity. The surface of carbon granules so refined becomes xuper active and contains the remarkable power of arresting nox ious gases and vapors from ventilation and recirculated air. This phenomenon is known as adsorption and is easily likened to flies clinging to fly paper. ROTO AIRE GAS AND VAPOR ADSORB ERS make it possible to greatly reduce, or even eliminate, con taminated outside air for ventilation purposes. Air conditioning, installation and operational expenses therefore decrease because there is no need-to heat or cool this additional air. There are no anoxia concerns because unavoidable infiltration (actors exceed by many limes the air volume necessary lor oxygen replenishment. Partial air detention type Roto Aire Adsorbers are designed to process air at high efficiency on a by-pass basis. Therefore only a part of the air passes through the carbon cartridges where up to 25% of air borne contaminants are removed. Their use is recom mended to process ventilation and recirculated air when ventilation air requirements are less than 10% of the total air volume. They are also recommended for use in systems where outside air is excluded and the total quantity of supply air-is recirculated. Air System Equipment ait fihcs 163 CAMBRIDGE FILTER CORPORATION 736 EAST ERIE BOULEVARD, SYRACUSE 1, N. Y. Representatives in Principal Cities Cambridge AEROSOLVE Filter Efficiencies 35% to 95% Discoloration Test, Atmos. Dust Cambridge High-Velocity AEROSOLVE Filter Cambridge ABSOLUTE Filter Guaranteed 99.97% Efficient on 03 Micron Particles High-Efficiency Air Filters Cambridge air filters are positive, strainer-type, high-efficieney filters which provide trouble-free air cleaning without electric, water or drain connections. They are economically installed and, except for infrequent re placement, require no maintenance. In relation to efficiency, initial pres sure drops are exceptionally low. Cambridge AEROSOLVE Filters Consist - of permanent cadmiumplated steel frames with easily re placeable and interchangeable car tridges available in' efficiencies of 35 percent, 85 percent and 95 per cent efficiency (discoloration test with atmospheric dust). This test was developed by the National Bu reau of Standards and is used for rating electric precipitators. Most commercial filters test 5 percent to 15 percent- by this method. Changes "in efficiency requirement are easily met without major change in the system simply by substituting car tridges. Cartridges slide easily into frames and are secured by quickactine fasteners. Integral prefiltersare available where desired. Standard units are designed for face velocity of 250 fpm and can be used at higher velocities by V-ing the filter bank. High-Velocity units, face velocity 450 fpm, can be' in stalled in the plenum in a straight bank, for even greater economies. Hfcft Velocity StUKlud 450 fpm 86 sq ft. 24' X 24' 250 fpm 250 fpm 500 cfm 43 sq ft. 22 sq ft. Low Pressure Drop In relation to efficiencies, the initial static pressure drop of AERO SOLVE Filters is exceptionally. low: AEROSOLVE 95 AEROSOLVE 85 AEROSOLVE 35 Attrcft DitaleratU* EfitUacy............................... Initial Ap (Standard)............................. Initial Ap (High-Vet.)...:..................... Final Ap (Both Types).......................... 9i ptruM 0.35' w.g. 0.45* w.g. 0.80* w.g. IS perctaS 0.22* w.g. 0.32* w.g. 0.60* w.g. JS ptrcea 0.16'w.g. 0.25' w.g. 0.60' w.g. The great area and thickness of AEROSOLVE filter cartridges provide long life which, with low initial cost, guarantees economical owning and operating costs. _ . Cambridge ABSOLUTE Filters New glass-asbestos filter medium now used in ABSOLUTE Filters is an im provement both in efficiency and in air handling capacity over the medium which Cambridge originated for removal of radioactive particles from exhaust sys tems in ABC installations. 99.97 percent removal of 0.3 micron particles is guaran teed. Essentially removes all smoke, dust, bacteria and mold spores is widely used by industry in applications where the highest degree of air clean ing is required. Every filter individually tested. Maximum penetration of 0.03 per cent guaranteed. Initial pressure drop 2.0 in. w.g. at rated air flow. Each filter self-supporting--no permanent frame re quired. Easily installed. Standard size units from 30 efm to 1375 cfm in stock for immediate shipment. Special sizes and shapes available on order. 1100 cfm units 24 in. X 24 in. X ill* in.; filter area over 200 sq ft. Standard A-series withstands 220F and 85 percent RH. Other series available for extremes of temperature, humidity, fire resistance and corrosion. Table of Sizes Model Sue, in. ity CFM at I' wg. 1-25 1-50 1-600 1-1000 1-1250 8 X 8 X 3H, 8X8X5% 24 X 24 X 5% 24 X 24 X 11% 24 X 30 X 11% 30 50 650 1100 1375  164 connnEnTBL P.O. BOX 1647 Air System Equipment . a* fih ) (Wn RIR FILTERS, Inc. LOUISVILLE, KY. CONTINENTAL CONOMATIC Roll-Away Type Air Fil ters... provide mMrimum Biter area for filter size. Automati cally advances viscous coated, glass-fiber filter media as needed. Media Saver minimizes cost. Trouble-free direct drive saves maintenance. ' Write for Bulletin No. 80S. CONTINENTAL CONOMANUAL ... manually operated dry-type filter similar to Conomatic, for use where low installa tion maintenance cost limits preclude automatic equipment. Simple band-wheel advances Vi-meh-thick. disposable synthetic media blanket which has high dust-holding capacity, is mois ture-, fungus-, and fire-resistant and will not part or "shed" when handled. Write for Bulletin No. 860. CONTINENTAL ANTOMAT1C, SELF-CLEANING Air Filters ... viscous im pingement type. Features: Patented E-Z-Wash media, "Ferris Wheel" action of continuous rotating filter-curtain, and positive automatic flush-cleaning of curtain in each rotation cycle. - Ferris Wheel action passes filter sections from front to rear curtain without re versing them to the direction of air-flow ... thus eliminating problem of trapped dirt being blown into clean air stream. Ham action tilts and lowers each filter section while in oil reservoir so as to force fully flush filter oil through the media counter to air-flow. Write for bulletin No. S10. CONTINENTAL DYCON Dry-Type Air Filters ... have excellent oust-noiamg capacity. EScient media blanket of specially prepared synthetic fiber. Low mainte nance eo.tr qoickly and easily restored to original resistance by oold-rater nrarng. No oil involved. Standaid sires. Type CA-24, 8 m. thick. Type CA-20, 4 in. thick. Type DY, 1 in. thick. Write for Bulletins No*. 460 and 570. CONTINENTAL E-Z-WASH Unit Filters ... use same advantageous patented me dia as above. Can be washed easily by brisk cold water nosing, and quickly re-oiled with E-Z-Oil spray bomb or dip tank. Standard sizes, 2 in. or 4 in. thick. . Write for Bulletin No. 488. CONTINENTAL TYPE LV Air Filter... crimped galvanized hardware cloth and screen wire in highly rust-resistant, hotdipped galvanised steel-channel frame assure long service-life for the LV viscous impingement air filter. Bale handles op ' Write for Bulletin No. 600. CLEBRALL Air Filters ... to approach totally dust-free conditions ... provide efficiency in excess of 9957 per cent on 05-micron particles as tested by DOP standard procedure re quired by Atomic Energy Commission. Available in standard sizes ranging from 30 to 1200 cfm rated capacities at 05 in. WG. Size 24 m. x 24 in. x 1114 in. has 1000 cfm capacity. Three standard types meet operating conditions in tempera tures up to 1000F or high humidities. Special filters for use up to 2300F or in highly corrosive fumes also available. . Write for Bulletin No. 900. Air System Equipment aw raten at cka. 165 Dollinger Corporation CENTRE PARK ROCHESTER 3, N. Y. Filters for Building Ventilation, Air Conditioning, Engine Intake, Pipe Lines and Many Other Special Applications tEPRCSEWMnvES IN PHtNOPAL ONES STAYNEW MODEL A-3 AUTOMATIC FILTER An endless curtain type oil-bath filter for han dling large volumes of heavily dust-laden air at low cost. The efficiency of Staynew Model A-3 is outstanding among me chanical self-cleaning filters. Patented, exclusive Staynew Compressed Air Curtain Cleaners (5) are available for special conditions. SPECIFICATIONS Model A-3 Filters are sectional and may be bolted to gether to obtain any required capacity. Sections come in. two widths, 4 ft. 3 in. and 2 ft. 9 in. Curtain drive'and control mechanism (6) arranged either as an integral part of filter unit or for remote mounting, includes a H bp motor (7) driving through a reduction gear and a mo mentary contact time switch (8) for testing and checking curtain travel and compressed air control. All are mount ed on a common base plate (9) on clean air side of filter. Shear pin (10) is provided for protection of moving parts from accidental damage. Drive Motor operates for a few seconds at 15 minute intervals, and compressed air curtain cleanerscan be arranged tooperatesimultaneously. Write for Bulletin 500. STAYNEW PANEL TYPE FILTERS Model WKE: Dry-type finned panel filter for use in ventilation and air conditioning systems. Extremely large filtering area in relation to over all size. Adaptable to wide variety of filtering media--in fact, almost any medium obtainable in sheet form that can be crimped. Steel mesh on both sides of medium prevents sagging and makes the WKE fire-resistant (models available to meet Class I Fire Underwriters approval), and cleanable without possible damage from vacuum cleaning tool or cleaning nozzle. It may !<> be washed or dry cleaned when and if necessary. There are no cross bars, spacer bars, or other obstructions to interfere with the cleaning operation. Unaffected by tem perature changes. Filter cells are held in rigid box-type supporting frames of heavy gage metal by spring-loaded cam-type locking latches. Two lifting handles are provided on each cell. Filtering medium supplied already crimped and cut to size. It may be inexpensively replaced in 2 to 5 minutes right at the filter bank--no special tools required. Frames are drilled so that they can be riveted together to form a flat bank, or by the addition of angle uprights into a "V" or staggered arrangement,, Write for Bulletin 600. Viscous Panel (Model DPV): A per manent type panel for air condition ing systems used in heavy duty in dustrial service. Filtering media consist of a series of layers of crimped galvanized screen cloth and woven mesh. These media when coated with PD-10 Pingene Filter Oil form an unusually efficient filter. Model vbemn Modal opv DPV filters are cleaned easily with d **" live steam or by washing in a suit able solvent. Spring-loaded locking latches and lifting handles are provided as in Model WKE. Both Model WKE and DPV cells are furnished in 2 in. and 4 in. depths in various standard sizes. Write for Bulletin 700. ELECTRONIC FILTERS 1200 cfm ElectroSteymw Air Cleaner SocIt-Staynew Air Cleaner: Ionizer and Collector Cell built into one compact unit. Highly efficient--removes 90 percent of all air-borne dirt, including smoke, dust, pollen, oil mist. Available in single units of 1200 and 1800 cfm; any capacity in multiple units. Write for Bulletin 400. HV Electro-Staynew Air Cleaner: Has same features as standard model but requires less space. High velocity design permits 40% reduction in face area for any given capacity. Available in 1000 and 1500 CFM units, any capac ity in multiple units. Face dimensions: 1000 CFM unit--20' x 17* 1500 CFM unit--20' x 23' Write for data sheet. Electro-Staynew Mist Collector: EHmlnntoa S smoke and oil mist at its source. Mounted on or near high speed machine tools, an Electro-Staynew Mist Collector draws con taminated air from around grinding or cut ting operations and returns clean air to shop. A completely self-contained ventilating sys- BMfefrjioyOTtftem for machine tools. Mist CoSector Write for Bulletin 420.  166 Air System Equipment * luun wi CUtf.Tt Electro-air Cleaner Company Inc. Olivia & Sproul Sts., McKees Rocks, Pa. "In Greater Pittsburgh'* Representatives in Principal Cities Electro-air Hi-C, "High Capacity" Electronic Air Cleaners have been developed for ease of installation, maintenance-free operation and high efficiency. The entire line features a self-adjusting, ballasted, single circuit and selenium rectifiers. All parts, including selenium rectifiers are guaranteed for five years. All Electro-air equipment incorporates the patented "Inside Curve" Ioniser which means higher efficiency, reduced size of equipment, increased capacity and face velocity, and service-free operation. All sizes of Elec tro-air units are available with either vertical travel ing manifold or horizontal fixed manifold washing systems. The latest Electro-air engineering development is the new DetergentAdhesive System, Type "X", with "double action" DAX solution which is available with all sizes of Electro-air equipment. It is supplied as a "package" and is used to promote thorough washing and adhesive applica tion. DAX solution is injected into the wash water during the last Vs of the washing cycle, acta as a strong detergent, then dries and leaves an ad hesive coating on collecting plates and electrodes. ' Electro-air Detergent-Adhesive System Type "X "Bnilt-up line" equipment is manufactured in capacities from 10,350 cfm to 200,000 cfm for larger building areas. Each unit is made "to order" according to the specified height, width and cleaning capacity required, is assembled and tested at the factory, then match-marked, disassembled and shipped in well marked crates. "Built-up Line" units are al6o fur nished with "enclosures" complete with drain pans, fore and aft ducts, windowed access doors and complete wiring. Electro-air "Built-up Line** Enclosure Unit "Custom Line" units are furnished in capacities from 1,150 cfm to 21,360 cfm as complete "packages" and are designed for use in those cases where space is limited and access doors in ducts are not practical. Each unit is complete with the required number of collecting cells, drain pan, washing system and power pack. "Custom Line" Electro-airs are fur nished in either horizontal or vertical (up or down) air flow, and may be floor mounted or suspended. ' Electro-air "Custom Line** Unit ' "Compact line** Electro-airs, are moderately priced and are designed for easy installation in homes and smaller commercial or industrial build ings which have forced air ventilation. They are available in fifteen models, both horizontal and vertical (down) flow in capacities from 800 to 9,600 cfm. Horizontal flow models may be either floor mounted or sus pended. "Compact Line" units include most features of larger "made-toorder" Electro-air models. Electro-air "Compact Line** Unit Electro-air Cleaner Company, Inc. also manufactures low cost "Tec Line" units which are true electronic air cleaners (90 percent efficient as . determined by the National Bureau of Standards Dust Spot Test) for in stallation in small and medium size homes. Air System Equipment . Air risers 167 THE GEORGE EVANS CORPORATION MOLINE, ILLINOIS vtma Evans Lifelong Air and Grease Filters All Aluminum . . . Every Part Precision Made SEAL TIGHT HOLDING FRAME WITH PVC GASKET GIVES PERMANENT DUST TIGHT SEAL. Strapda and grids are scientifically sited and placed for holding ' maximum dirt Joad. Filter pack ha* larger grid openings on air inlet side progressing to smaller grid openings on air outlet side. Prevents face loading and choke-off of air stream. Ac complishes uniform depth loading ail through the pack. Every grid, every strand does its part. TURBULENCE AIR CLEANING ACTION. Dirt is slammed into the flat strands of mesh where it is-caught and held by talon like edges of these grids. Precision stamped openings force sir to travel many times filter depth from inlet to outlet side.. .. for high efficiency air cleaning. LOWER AND SLOWER STATIC PRESSURE RISE PER GRAM OF DIRT LOAD. Filter pack catches and holds dirt without strangling air stream. Filter remains in service longer: (1) without sharp increase in resistance (2) with fewer cleanings (3) with power costs held down. ' HIGH VELOCITY APPLICATION ... UP TO 1,000 FPM. Using turbulence air cleaning action (instead of screening or straining action) makes Evans filters particularly well suited to extremely high velocity requirements. The higher the velocity . . . the harder dirt is "slammed into the mesh where it is caught and held by the talon like edges of the strands. Filter's efficiency rises as velocities rise. DOUBLE ACTION ADHESIVE. Works as adhesive while filter is in service. Becomes a deter gent and helps wash filter when water is flooded on. IMPORTANT . . . When Evans filter fluid is used filters can be washed with tap water. FILTER CAPACITY CHART--CFM DELIVERY Gasket pressure locks filter into frame. No springs, latches or locking attachments. Slide filter into frame. Gasket auto matically grips it securely. Gasket is permanent (Polyvinyl Chloride). Stands up for years against compressive stresses' without breaking down. Un affected by oil or moisture. HOW TO SPECIFY EVANS SEAL-TIGHT FRAMES. ' Filter holding frames shall be heavy gage steel. Polyvinyl chloride gasketed on front of air inlet side. Gasket shall provide both positive grip for holding filter in frame and positive seal between filter and holding frame. Frames shall be double coat finished in black enamel. Frames shall bolt together. HOW TO SPECIFY EVANS LIFELONG AIR FILTERS. Filters shall be aluminum. Frame holding media shall be onepiece precision die-pressed heavy gage aluminum with edges . rounded. Corners machine fitted. Frame shall have drain holes in 3 comers of frame member. Filter pack shall be made of die-cut flat and corrugated aluminum fends packed with larger openings on inlet side progressing to smaller openings on . outlet side.  168 Air System Equipment FARR COMPANY P. O. Box 90187, Airport Station, Los Angeles, California NEW YORK LOS ANGELES CHICAGO AUTOMATIC FILTERS V ROLL-KLEEN TYPE H Incorporates the basic Roll-Kleen features in a compact as sembly which can be easily attached to most makes and models of air-handling units. Media moves horisontally across the air stream. The Type H uses standard Roll-Kleen media. Write for Bulletin B-HOQ~S. . air Fiiim , Farr Company 169- F/S FILTER The type F/S Filter is an all metai, eleanable, viscous coated impingement type panel air filter. Performs efficiently at either low or high (350 to 520 fpm) velocity. The F/S filter is especially effective in air containing a high percentage of lint contamination. The filter is available in % and l-% in. thicknesses, standard and special sizes. Write for Bulletin B-lSOt-I. Far-Air HP FILTER A deep-pleated, flameproof, disposable filter which iB pre formed, then folded before shipment for convenient handling and storage. The HP is popped open at the filter bank and easily inserted into a matching metal holding frame which remains permanently in place. After use, the HP will refold trapping all collected dirt in the deep, pocket-like pleats. Filter weighs approximately one pound depending on sise. Highly efficient in the small (0-5 micron) particle size range. Available in 16 x 20 in., 20 x 20 in., 20 x 25 in., and 24 x 24 in. sizes. All sizes are 8 in. deep. For use with or without pre filters at high or low velocities. Write for Bulletin B-lSOO-t. SELF-WASHING FILTERS These completely automatic units wash and re-oil them selves. Washing water and contaminated oil is immediately flushed away, eliminating messy sludge and oil sumps. There is no oil entrainment. Each unit has a safety deluge valve that automatically prevents fire from passing the unit- In stallation is simple and inexpensive. Write for Bulletin B-1000S. MICROLOC FILTER The FAR-AIR Mieroloc is a dry-type, renewable media filter which offers a selection of high efficiencies on'the D.O.P. test method. Each Mieroloc unit consists of 5 inserts.to hold the disposable media pads. The Mieroloc filter units are interlocking and include a panel filter holding frame. A single bank of Mieroloc filters pro vides for 2 stage filtration. Recommended for use after impingement filters where high efficiency is required. Write for Bulletin B-1303-1. MAGNAMEDIA FILTER Ultra-High Efficiency filters which meet ABC specifications for high efficiency and construction. Used to trap radioactive or other fine particle contamination. For laboratory and special industrial applications. Write for Bulletin B-1S04-1. A. disposable media filter which automatically changes the media in the face of the filter. Designed for Roll-Kleen media, an adhesive coated, glass fiber mesh, bonded to and rein forced by a lenoweave fabric backing. Use of this reinforced media permits a simple, direct drive media movement system. Auto-Control system includes prewired control boxes, electric gear motor and signal lights. Pressure operated media control is standard. Timer or combination control systems also avail able. Factory assembled in Sections 3, 4, and 5 ft wide and from 5 to 15 ft high. Write for Bulletin B-UfiO-l LINT KLEEN An automatic filter similar to the Roll-Kleen in appearance and operation. Designed for textile mill applications. Uses special, extra long media rolls. Write for Bulletin B-HDQ-6. HI-KLEEN A complete, two-stage, air-filtering system combining the Far-Air Roll-Kleen and HP filters in a compact unit. Total depth is only 38% in. Both stages use convenient, completely . disposable media. Offers exceptional efficiency, especially in. the 0-5 micron range. Write for Bulletin B-1400-4- Far-Air HIGH VELOCITY FILTER A high velocity, low resistance, viscous coated, impinge ment air filter for industrial and commercial applications. Available in 1, 2 and 4 in. thickness and all standard and special sizes. One piece frame; rod-reinforced construction. Specify handles. Special materials and finishes'-for marine, fume and other applications. Write for Bulletin B-100-tB. GREASE ELIMINATORS FAR-AIR Grease Eliminators halt the deposit of grease and lint in the air ducts. Available in one-sided and two-sided models in sizes to meet any size requirement. For restaurants and commercial kitchens. Write for Bulletin B-t0t-6.  170 Air System Equipment MINNEAPOLIS-HONEYWELL REGULATOR CO. Minneapolis, Minnesota NEW SELECTOR SERIES OFFERS AN ELECTRONIC AIR CLEANER FOR EVERY REQUIREMENT Hi Velocity Cell Provides air cleaning efficiency of 98 percent at an air veloc ity of 600 fpm. A greater efficiency will result at lower speeds. Honeywell Hi Velocity deaner should be specified when maximum deaning is desired, or when unusually high velocities are common. X-in. plate interval. AC/ME Cell Offers advanced capacity for dirt loading and maximum deaning efficiency ar moderate air flow rates. 90 percent effident at 600 fpm. This cell should be used in most normal air-conditioning applications. Reduced velocity will result in greater effidency if desired. %*in. plate interval: Hi-Load Cell Designed to provide great capacity for dirt loading. Out standing for air-conditioning applications requiring wider -plate interval to reduce frequency of plate washings. Honeywell Hi-Load cell is given rating of90 percent deaning effidency at an air velocity of 400 fpm. H-in. plate interval. 6 -e -g S' oneywell's Selector Series of Electronic air deaners H offers you a choice of three air-cleaning cells. The cells identical except for the number of dirt-collecting plates cell and the spacing between places. Partides as small 001 microns can be stopped by a Honeywell electronic deaner. After being charged positively in a powerful electrostatic field, partides are attracted by grounded places where they are collected. Periodically, the unit is flushed arid deansed by a built-in water-washing system. Honeywell electronic air deaners can remove dgarette smoke, bacteria, spores, dusts and corrosive mists. ' They^protect large investments in machines, mer chandise, fixtures and lessen deaning and redecorating costs.5 ALL HONEYWELL ELECTRONIC AIR CLEANERS ARE WARRANTED FOR ONE YEAR AGAINST FAULTY WORKMANSHIP OR DEFECTIVE MATERIAL Honeywell Activated Charcoal Filters Where it is necessary to remove odors as well as to dean dirt from the air, we recommend Honeywell Activated Char coal Filters should be used with the Electronic Air Cleaners above. In addition to removing odors, these Activated Charcoal Filters cut air conditioning costs by reducing the amount of outdoor air intake normally required to diffuse odors. Four sizes available. Capaaty of the filter shown is 1000 cfm, resistance 0.2 wg. - FOR MORE INFORMATION, CALL YOUR LOCAL HONEYWELL SALES OFFICE Air System Equipment *ir . 171 Owens-Corning Toledo 1 OWEN5-CORX1 X C Fiberglas Corporation Ohio 1 AIR FILTERS AN AIR FILTER PRODUCT TO FIT MOST OF YOUR COMMERCIAL NEEDS taken to see that fan capacity is adequate to overcome increased resistances. Rated capacities are 800 cfm at 300 fpm for standard 20 X 20 Dust-Stop Filters and 1000 cfm at 300 fpm for 20 X 25 filters. a. Filter Adapter Frame for-filter banks, b. Mat-Faced Filter for paint spray booth applications, c. Pad Media Filter for room air conditioners, d. Bonded Mat for strainer type air filtering, .e. PF-115 for special high efficiency filtering applications, f. Filter wool, type TWL, for dry type specialty applications, g. Com mercial and Industrial Filter for velocities of up to 500 fpm nominal, h. Dust-Stop Filter for velocities of up to 300 fpm nominal, i. Die-cut Aerocor for liquid fuel applications, j. Special molded shaped Aerocor for Jet Fuel-Water Stripper Elements. . THE FILTER A replacement type filter that since 1931 has offered dependable air filtration, easy installation and con venient maintenance at low cost, for filter banks and other commercial or industrial filtering applications. Standard Dust-Stop Filters are designed for use in filter banks and equipment where velocities do not exceed 300 fpm. The Dust-Stop 450 series may be used with velocities up to 500 fpm. Care should be DUST-STOP FILTER FRAMES Frames are designed for the convenience of the engi neer in constructing filter banks. Metal frame is uni- versal style, suited for use in flat or "V" banks. De signed-in, self-locking device permits fast, economical assembly. Made to take 2 in. or 4 in. depth of standard 20 in. X 20 in. or 20 in. X 25 in. filters. Black painted or galvanized finish. Front, back and side-angle uprights for Y-bank assembly are also offered in 20 in. incre ments up to 160 in. length. DUST-STOP RESISTANCE INDICATOR ' Dust-Stop Resistance Indicator acts as a guide to economical bank maintenance. With adjustable filterchange- marker set at resistance level specified by engineer as point where filters should be changed, this^, indicator provides a guide to when filters should be changed and insures operation at rated capacity and efficiency. Available direct from H. 0. Trerice Co., 1420 W. Lafayette, Detroit, Mich. For technical data on Dust-Stop Filters and Frames, as well as Fiberglas Flexible Media, write: Owens-Coming Fiberglas ' Corporation, Dept. HVAC-1, P.O. Box 901, Toledo I, Ohio. * Fiberglas and Dust-Stop are trade-marks (Reg. U. 8. Pat. Off.) of Owens-Coming Fiberglas Corporation for a variety of products made of or with fibers of glass.  172 Air System Equipment Air Fibers Pittsburgh Plate Glass Company FIBER GLASS DIVISION One Gateway Center Pittsburgh 22, Pennsylvania Where clean air is a necessity for either residential, commercial or industrial applications specify GLASFLOSS filters. Products of the Pittsburgh Plate Glass Company, these filters are composed of long and fine glass fibers. Because of this fineness, they furnish a greater dust-collecting area and provide unusually complete filtering action. GLASFLOSS filters are available in three forms, to suit all filtering requirements: "' GLASFLOSS STANDARD AIR FILTER--Millions ^of fine, bonded glass fibers, treated with,a special fire-resistant, dust-catching adhesive, trap and hold more dirt.. New Safety-Grille design makes filters stronger, eliminates danger of cut hands from old-type metal grilles. Excellent for home heating and air conditioning equipment. GLASFLOSS I-S FILTER--To the long, fine glass fibers used in the STANDARD Air Filter a special strainer mat has been added on the air-exit side. This mpfin.q that the I-S filter is actually two filters in one. For industry, where clean air is essential, or in the meticulous home equipped with forced air heating, Glasfloss I-S provides new high performance air filtering. . filters who are faced with the problem of continuous replacement. The Glasfloss Roll-Pak provides sub stantial savings... as high as 30 percent. It offers quick replacement of filter media, and is available in rolls of 40 in. wide and 10 ft. long and in *4 in., I in., and 2 in. thicknesses, packed five rolls per carton, to suit every size commercial air filter. Also available in cut pads. GLASFLOSS STANDARD AIR FILTERS GLASFLOSS I-S AIR FILTERS Nominal Sixes 20* x 25' 20*x20' 16' x 25' 16' x 20* 15' x 20' 10' r 20' 10' x 10' 12' x 30**' x 1' 20' x 22K' * 1' 16' x 22)4' * I* 20' x 25' 20' x 20' 16' x 25' 16' x 20' 15' x 20' ~ Votmncol Ail Clwnrtf 1000 CFM 800 CFM . 800 CFM 640 CFM 600 CFM 400 CFM 200 CFM 735 CFM 890 CFM 715 CFM 1000 CFM 800 CFM 800 CFM 640 CFM 600 CFM ACTUAL. DIMENSIONS ____ | Width' | Haiht | Thickness ,| l" Filter" I r'Filter TOLERANCES ~ PbaOflO" Mima H" Piss or Minn* X" 19*K,,' 19*4' is1**.' 14K.' 9'tf.' li'W 'm.t" 19**' 19*4k 19`Hs' 19`Ke' VXj' 30K 22X.' 22Hfl lHs'- l**e' ;k,,lX*' `Ms' i`K' I'Xo' I'Ks' i`K- 1' only 1' only 1' only !%' 19*** 16Ha' 151*?#' 14Ks' 19*4* 19*4* 19K.' Ke' l`*fe' UKs' Air System Equipment au fih*** 173 RESEARCH PRODUCTS CORP. MADISON 1, WISCONSIN Air Filters for Heating and Ventilating--Grease Filters for Kitchen Exhaust Systems--Paint , Arrestors--Automatic Humidifiers RP AIR FILTERS Viscuous impingement, with controlled turbulence caused by scientifically staggered baffles is a feature of every R P Air Filter. In addition to high efficiency dust, dirt and pollen removal, R P washable air filters offer a bonus feature-- ODOR REMOVAL--through the use of Super Filter Coat Adhesive. E Z KLEEN AIR FILTERS Industrial Air Filters The aluminum, washable air filter that features easy clean ing and moderate cost: Available in )4. in., 1 in. and 2 in. thicknesses--all designed for velocities up to 350 fpm. Multi-Velocity E Z Kleen Air Filters For commercial-type installations, where a strong, yet light weight filter is required. Designed for both low and high ve locities (350 to 520 fpm) and available in 1 in. and 2 in. thick- R P Industrial Air Filters are Multi-Velocity filters (250 to 600 fpm) with extremely low initial resistance, and slow build up resistance. Outstanding where a rugged, heavy duty filter is required for industrial installations: In 1 in., 2 in., 3 in. and 4 in. thicknesses. Holding frames for filter banks, combina tion lift and lock handies, lift or bail handles are available. R P ADHESIVE R P Super Filter Coat adhesive performs all the normal dust and dirt trapping functions, but also is scientifically compounded to adsorb and absorb odors--and prevent their re-circulation in the air stream. A "built-in" detergent sim- ' plifies the filter washing process. Available both as a concen- trate and in ready-to-use form. ' GREASE FILTERS Efficiency in excess of 99 percent on grease vapors, gleam ing appearance, ease of cleaning and light weight* have made the R P Grease Filter a volume performance leader in its field. Inset illustration shows handle lock--also available with lift or bail handles. A free, comprehensive data booklet' on kitchen exhaust systems is available on request. PAINT ARRESTORS Specially designed, inexpensive, replaceable R P Paint Arrestors trap paint over-spray from spray booth exhaust sir. Efficient in operation, R P Paint Arrestors are flexible and versatile--can be used in existing booths and in new installa tions. Easily installed (with Snap-in Grid to hold Paint Ar- . restor in frame), and maintained--reduce down-time and ' floor-space requirements. ... . APRILAIRE AUTOMATIC HUMIDIFIERS Residential--3 models available ... all featuring controlled high capacity (up to 92 lb of water per hour). Plenum Model illustrated; Universal Model for buildings with wet heat; Portable Model, requiring no installation. Industrial-Capacities from 2** to 10 gph . . . dust-free operation .. . positive control, models for all types of heating.  174 Air System Equipment ai* F&m TRION, INC. 1000 Island Avenue McKees Rocks, Pa. in Metropolitan Pittsburgh Toronto* Canada Dortmund, Germany Zurich, Switzerland Tokyo, Japan Representatives in Principal Cities Designers and manufacturers of equipment for cleaning and purifying air and other gases TRION ELECTRONIC AIR CLEANERS High efficiency air purification equipment. Electronically removes up to 97 per cent {National Bureau of Standards Dust-Spot Test method using normal atmospheric air) of dust, dirt, smoke, pollen, and germs from air. All airborne particles are electronically charged (positive) as they enter the Trion. They are then attracted to and collected upon grounded plates An integral washing system flushes the'dirt to a sewer. FIELD ASSEMBLED UNITS The specific use of field assembled units is-for installa tions requiring the cleaning of air in comparatively large volumes. An example would be multiple floors of a building. Units are sized to specifications for han dling any volume of air. The unit consists of all basic components including power pack(s) for supplying the necessary current; required number of dirt collecting cells; and a built-in water spray system for removing collected dirt from cells. CUSTOM-BUILT PACKAGED UNITS As an aid to the architect, engineer and installer, Trion will supply equipment constructed as a complete pack age. Packaged equipment is available for installation where space' is limited. Units are designed for floor mounting or ceiling suspension and for horizontal or vertical air flow. Complete unit includes all basic units housed in a corrosion-resistant metal cabinet including drain pan. Sizes range from 1,300 to 10,000 cu ft of air per minute. PACKAGED RESIDENTIAL UNITS The standard packaged units are designed primarily for residential and small commercial installations. Because of ease of installation, they are also being widely used for industrial and commercial applications where the volume of air to be cleaned is relatively small. Units are available in suspended models or for floor mounting in sizes to handle from 800 (average 5-6-room home) up to 9,600 cu ft of air per minute. Units are sized to the capacity of the furnace or air conditioning blower. OIL MIST PRECIPITATOR UNITS These units are specifically designed for the elimination of coolant oil mist and smoke emanating from high speed cutting, grinding, and machine operations. Flexibility is provided in that they can be mounted on the floor, on the machine, or suspended from roof trusses. The basis components are the same as for field- assembled units. Under normal machining operations the daily oil recovery from a Trion Oil Mist Precipi tator may be as much as 3 to 5 gal. Air System Equipment Air Filters CRS! VORTOX COMPANY Claremont, California Panel Air Filters for all Industrial Applications 175 Vortox Panel Air Filters are of the cleanable, impingement, viscous-coated type with exceptionally low air flow resistance. They are made for use in air conditioning ventilation, range canopies, engine intakes, and general air filtration. . EFFICIENCY. Vortox Panel Air Filters are efficient at both high and low air flows. Consequently to reduce costs of the original installation or to save space, fewer Vortox Filters may be used at higher air velocities. To assure a longer service life, more Vortox Filters may be used at lower velocities. In either case, Vortox Panel Air Filters provide better cleaning at lower cost. Filter with Frame ` Vortox Type VR Panel Air Filter illustrated above is the type used on engine intakes and in car bodies of die sel locomotives. It is constructed to withstand the se vere usage of locomotive service. It has exceptional characteristics as in all types of Vortox Panel Air Eilters. OPERATION. Numerous changes in direction of dust laden air cause the dust particles to impinge on the adhesive viscous-coated surfaces of the filter element. Coarser particles collect near the entrance, while finer FILTER ELEMENT. Fabricated of elastic units of fine steel wire positively interlocked to provide a permanent filter, the element offers many advantages: (1) In a 2 in. x 20 in. panel there are from 9,300 to over 15,000 feet of fine steel wire, depending upon the type. (2) ' Even distribution of filaments exposes innumerable viscous-coated surfaces to the air stream, thus obtain ' ing the most effective cleaning for space occupied. (3) Proper spacing of filaments prevents clogging and as sures maximum dust removal efficiency. (4) Structural strength and permanent resilience combine to with stand "packing" effect of vibration and pulsation. particles penetrate to a greater depth. As the entrance becomes saturated, the cleaning action takes place deeper in the filter and the restriction is increased slightly. Increased restriction in certain sections of the filter diverts the air to cleaner sections, thus distribut ing the dust load for a higher over-all efficiency and a greater total dust-holding capacity. EASY TO CLEAN. All dust and lint are easily and completely flushed from the filter by water or steam sprays. Nominal Size of Actual Outside Panel Inches* Dimensions Inches Outside Dimensions Capacity Range of Holding Frames In CFM** Inches 16 x 20 x 2 16 x 25 x 2 20 x 20 x 2 20 x 25 x2 15H x .WH * IK \SK X 24H X IK 19*$ * 19M X IK 19*$ x 24?$ x 1H 640 to 950 800 to 1200 " 800 to 1200 1000 to 1550 16H x 2OH x 2 16*$ x 25*$ x 2 20*$ x 20*$ x 2 20*$ x 25*$ x 2 These filters are also made in 4*io. thickness. - Some filter manufacturers specify very high velocities which are applied to cer tain internal dimensions of the filter. The range of capacities stated above are com puted on the basis of average to high velocities applied to the total filter area using the actual outside dimensions of Vortox Panel Air Filters.  176 Air Syatem Equipment mr chnni Westinghouse Electric Corporation SluHevanf Division Heating, Ventilating, Cooling, Dehumidifying, Electronic Air Cleaning and Mechanical Draft Equipment Main Office--Boston 36, Mass. OIBe, in Ptineip,i cuic PRECIPITRON ELECTRONIC AIR CLEANERS By catching and holding dust, dirt, smoke, pollens and bacteria as small as one-tenth of a micron, the West inghouse PRECIPITRON provides clean air for homes, hospitals, public buildings, commercial and mercantile establishments and industrial plants. A ' product of research and development by Westinghouse engineers, PRECIPITRON is available in unitary and field assembled models, all` easily installed and with capacities to meet exacting requirements. HIGH CAPACITY UNITS--available from 2500 to 120,000 cfm for use in central ventilation and air con ditioning systems. Units feature automatic washing-- built-in high voltage connections--amplified erection. IN-LINE AIR CLEANER SECTIONS--match stand ard Air Distributing Units for Air Conditioning, Heat ing, Ventilation and Air Cleanliness control..Sizes from 2000 to 28,800 cfm--built-in traverse washing, in econ omy or automatic models. HEAVY DUTY UNITS--especially for industrial applications where dust concentrations are greater. Available with one side or dual side automatic washing, remotely controlled in sizes and capacities from 6000 cfm up. ' CABINET UNITS--available in high capacity and heavy duty models. Self-contained--built-in traverse washing--suspended or platform mounting. Capacities 2000 to 28,000 cfm in high capacity, 2000 to 12,000 in heavy duty models. ' RESIDENTIAL UNITS--for home beating and air conditioning systems. Save on household cleaning and redecoration--cost little to operate. OIL MIST CONTROL UNITS--collect coolant oil mists generated by high speed machinery. Fan is built-in for individual machine ventilation. (J-80677) High Capacity Units Catalog 1460 In-Line Air Cleaner Sections . Catalog 1636 Heavy Duty Units Catalog 1413 Cabinet Units Catalogs 1465 aod 1425 Residential Bulletin B-5203 Oil Mist Catalog 1450 Air System Equipment BALTIMORE AIRCQIL COMPANY, INC. P.O. Box 7322, Baltimore 27, Maryland EVAPORATIVE CONDENSERS -- COOLING TOWERS B.A.C. EVAPORATIVE CONDENSERS 10 to 350 Tom for Freon 12, 22 or Ammonia 177 Blow-Tbrougb Centrifugal Fans Maximum'Accessibility Oraw-Tbroegb Centrifuged Fans Minimum Floor Space Blow-lbrough Propeller Peas For Horsepower Saving One of the most complete lines of Evaporative Con densers offered. From 3 different models, you can select the unit that exactly suits your installation requirements. Baltimore Aircoil Company has specialized in the manu facture of Evaporative Condensers for 20 years and is a recognized leader in this field. B.A.C. COOLING TOWERS Up to 400 Tons in a single, factory-assembled unit A new line of adjustable capacity Flexi-Towers is now available. Without any mechanical changes to the tower, Flexi-Tower capacities can be varied over a wide range to meet changing load requirements!. All B.A.C. units require as little as Yi the space needed for field-erected cooling towers. This, plus their quiet operation, makes them ideal for today's modem build ings where the cooling tower must be inside or otherwise hidden from view. These units are of rugged, hot-dipped galvanized construction, and even the largest sizes require only a simplified and inexpensive base. 178 Air System Equipment c~Ub* t Binks Manufacturing Company 3130-36 Carroll Avenue, Chicago 12, Illinois . Representative in all.principal cities BINKS NATURAL AND MECHANICAL DRAFT COOLING TOWERS Biab atmospheric spray cooling towers Binks blower type mechanical draft cooling lowers Small sizes, in a variety of standard units with capacities ranging from 10 to I2S gpm--larger units handle from 600 to 1,200 gpm. Special designs fur nished in sizes of exceptionally large capacity. Standard tower capacity and temperature performance are based on nozzle pressure of 7 lbs per sq in. Ask for Bulletin Sit. Atmospheric cooling towers. Type **T'* The squirrel cage blower provides ex tremely quiet operation. Available in single or multiple types, capacity range from 9 to 800 gpm of cooling water. Ask for Bulletin 477-A. Binks multi-finned, plastic decked induced draft cooling towers Binks steel eased induced draft cooling towers Towers of this type are of the spray filled or deck filled type--made in 20 ;standard sizes of sq ft rated area. Larger :models are engineered to specification. Air propulsion assemblies for either type can be arranged for V-belt or reduction gear drive, as required. Ask for Bulletin SSS. Induced draft towers, Types "2-K-S". "2-K-W" New POLYETHYLENE plastic decking provides efficient evaporative cooling surface in small area. No nozzles needed for initial water break-up. Decking slides out for easy-cleaning maintenance. Ca pacities from 15 to 180 gpm. All com ponents pre-assembled for easy installa tion--hot-dipped galvanized. Fan is stainless steel. V-belt drive. Ask for Bul letin WT-601. Induced draft towers. Type "Watertemp" BINKS SPRAY NOZZLES FOR EVERY PURPOSE Binks non-clogging Rotojet spray nozzles Non-clogging Rotojet nozzles are the heart of every Binks Standard small and medium Rotojet nozzles are machined from water cooling system. They account largely for the efficiency brass bar stock, but can be made on special order from monel, and satisfactory operation of Binks water cooling installations. In addition to cooling tower applications, Sinks Rotojet noz zles have found a wide number of uses in brine-spray and quickfreeze refrigerating systems, air-washing equipment, metal - cleaning and treating machines, chemical plants, etc. Rotojets produce a uniformly fine fluid breakup in a hollow cone pattern. Binks imafl and medium capacity Rotojet nozzles To fit W to y* in. pipe connections. Regu larly supplied in brass, with male or fe male threads, as specified. Discharge ori fices are available over a considerable range for each size. Rotojet nozzles of this type are designed on the side inlet whirl chamber principle, which produces a fine fluid breakup and a uniform spray stainless steel, or other machinable metals. Large, heavy-duty -Rotojet nozzles for use in large cooling towers and spray pond installations, are cast from high quality brass with precision machined threads and orifices. These nozzles may be cast in other metals for special purposes. Binks Spra-Rite nozzles Produce a solid mass cone spray pattern. Small sizes for V* to * in. connections are widely used for air washing, cooling, brine refrigeration, rapid evaporation processes, filtering systems, chemicals, etc. Binks large capacity Spra-Rite nozzles To fit 1 to 3 in. connections meet a variety of heavy-duty uses in blast furnace - gas washers, vibrating and re volving screen coal and gravel washers and water cooling. pattern. Binks heavy-duty Rotojet nozzles Free technical bulletin and engineering service To fit 1 to 2Vt in. pipe connections. Fe male threads only. Discharge orifices available in various sizes, from 3io to DHs in- The totally unobstructed in volute type of whirl chamber produces a uniformly fine water breakup at low pressures (5 to 7 lbs). Rinks pneumatic atomizing nozzles Series 50 nozzles are designed for use wherever conditions of controlled hu midity must be maintained, as in the storage of perishable products, paper storage and printing plants, textile mills, greenhouses, etc. Nozzles of all brass construction deliver round or flat spray and are designed for use with automatic siphon or pressure feed installations. Binks 28 page Bulletin No. 5600 contains ' a wealth of useful information for any one specifying spray nozzles for air conditioning, refrigeration, humidifying, heating ana ventilating, or similar heat transfer processes. Nozzles shown above and all other nozzles in Binks line are illustrated and described. Data given in clude nozzle dimensions, capacities and spray angles. Cutaway drawings explain nozzle operation in many cases. "Blue print" drawings show installation de tails for heating and cooling uses where this information is reejuirea. Write for a free copy without obligation. Binks engineering service in planning and installing cooling systems is available without obligation or cost to architects," heating and ventilating engineers and builders. Air System Equipment CmUoi t 179 FLUOR PRODUCTS COMPANY Air Conditioning 0.and RoMgsraUon CooflngToww AC & R Division: Meadows Bldg. Dallas 6, Texas General Offices: 12000 E. Washington Blvd. A Division of the Fluor Corporation, Ltd. Whittier, California nutria Sales Offices. Acents & Representatives in: Albuquerque, El Paso,"Detroit, Philadelphia, Shreveport, Phoenix, Amarillo, Louisville, Mission, Kan., Memphis, Atlanta, Jacksonville, St. Louis, Cincinnati, Austin, Dallas, Houston, Charlotte, Minneapolis, Washington, D. C., Pittsburgh, Miami, Orlando, Daytona, Tampa, Birmingham, Richmond, New Orleans, Whittier, Corpus Christ!, Denver, Salt Lake City, Oak Park, New York, San Francisco, Cleveland SERIES 3 COOLING TOWER Offers complete coverage for the Air Conditioning, Refrigera tion System field with appeal for architectural design. The girthing material is % in. corrugated asbestos-cement, having the corrugations in the horizontal plane. Compact counterflow d^ifrn requires minimum plan area, and fits rigid space requirements. Supporting structure may' be oriented in any direction. Perimeter anchorage and uniform column spacing simplify design of supports. Water inlets may be located on any waif. The tower is offered with either V-Belt or gear drive. Single and multiple cells cover any required capacity of 40 tons and up. Gives you these extra features ... - Rugged Construction The entire tower structure with its tension type bracing and thru .bolting of all members is de signed to withstand 30 lb wind load (100 mph). Wood stress values are in accordance with the U. S. Forest Products Handbook. . ` Poly-Grid Fill Fluor patented polystyrene Poly-Grid fill gives more cooling per cubic-ft than any other fill available, reduces toted operating weight by K to ^ over conventional wood fill towers. Wood Fill (illustrated in right of cutaway) also available. Redwood Distributing Systems Header and laterals of redwood stave construction are completely non-corrosivc. Iow pressure splash plate units of non-ferrous material are non* clogging and selfmraining. Standard Accessories Galvanized steel hardware, wood ladder, and redwood basin with sump, sump cleanout, overflow- drain and makeup float valve. __ Optional Accessories Handrails, Fan guard, non-ferrous hardware. Fluor Air Conditioning and Refrigeration Cooling' Towers are available thru exclusive Representatives in all major market areas. Experienced service and erection personnel are ^ strategically located to render service to the owner when and' where needed. -' . Write for additional information. SERIES 2 COOLING TOWER This tower is offered for installations requiring minimum height, with less critical limitation on plan area. The c&pacity range is similar to that of the Scries 3 Cooling Tower. Write for additional information.  180 Air System Equipment cu>t ti E. D. Goodfellow Co., Inc. Memphis, Tennessee COOLING TOWERS GOOD-FELLOW CF Series: These models are pro duced in capacities from 2 to 100 TR. They are avail able with our standard corrosion resistant finishes or hot-dipped galvanized (after fabrication). Standard units have double air inlet and vertical discharge. Front or rear horizontal discharge and/or front or rear air inlet are available on order. This series is available with fan motor only, or with separate arrangement for closecoupled pump mounting. These models are leakproof. Models 15 tons and larger are constructed in three sec tions to facilitate erection and installation. They are normally shipped completely assembled. We believe the CF Series is one of the most versatile types of cooling tower available. CF Series P Series ___ > GOOD-FELLOW P Series: These models are manu factured in tonnage from 3 to 180 TR. All sizes of this series are designed to withstand a wind pressure of 30 lb per square foot. Large diameter slow speed fans produce efficient and quiet operation. Decibel ratings are furnished upon request. . Clear heart Redwood is used for deck filling. Inlet and discharge louvers are also of Redwood. All models P8 and larger can be completely taken apart, the largest section being the cold water basin. Motors on all models through P30 are mounted inside of tower casing, All models of this series are HOT-DIPPED GAL VANIZED after fabrication. They 'can also be supplied with corrosion resistant Epon epoxy exterior and Epon Coal-tar pitch interior finishes. Air System Equipment c~iib t. (Hjbvens COOLING TOWERS Division of Havens Structural Steel Company 1713 Crystal Kansas City, Missouri Standard and Custom-engineered Cooling Towers from 5 to 600 Tons Representatives in Principal Cities of the U. S. 181 Models 5 through 15 Tons HAVENS "33 Series" 5 to 75 Tons FEATURES ! All steel parts hot dipped galvanized after fabrication. Heavy Fan Screen Belt Guard Weather protected motors Stainless Steel Fan Shaft (our own bearing design) Stainless Steel Fan Blades Corrosion-resistant cast-iron sheaves Steel sheets, heavy gauge hot rolled mild steel ' The "33 Series" is recommended for residential and small commercial installations. The units are shipped assembled, ready for installation. Water tray distribution .system assures ample spread over all-heart, California redwood fill. All steel parts are hot dipped, double galvanized before assembly. Towers can be disassembled and reassembled with ease when necessary. Special fan bearing design assures quiet, trouble-free operation for years; it requires little maintenance. Models 20 through 75 Tons HAVENS "V SERIES" Models 80 thru 600 Tons (Models above 200 tons are field erected.) Recommended for medium and large commercial and industrial installa tions. Low, modern silhouette for pleasing appearance. Transite casings (corrugated cement asbestos board) Unique bearing design cuts main- _ tenancd costs. Models 80 to 200 tons are factory- assembled units--larger tonnages are field erected. Havens "V Series" Cooling Towers are ruggedly constructed to stand years of service under the most adverse weather conditions. ' Wood fill is California clear, all-heart'red wood with unique tray arrangement to gain most advantageous water distribution. , The variable pitch fan provides versatility. To minimize installation costs detachable hoisting yoke is furnished with each tower. Product bulletins and specification data available on request.  182 Air System Equipment c..u* t, Lilie-Hoffinann Cooling Towers, Inc. Exclusive Builders of Cooling Towers Since 1898 1450 So. Vandeventer Ave., St. Louis 10, Mo. Two Modern Plants--St. Louis, Mo., and Plainview, Texas LILIE-HOFFMANN CROSS FLOW TOWERS ... Outstanding for its "Low-Hite" and low pumping head. Ruggedly constructed to serve intermediate sized air conditioning and refrigeration installations. Appear ance designed to fit and complement modern architecture. Economical in first cost as well as operational cost, yet same high standard of quality of materials and mechanical equipment are maintained. Bulletin CM-456 LILIE-HOFFMANN COUNTER-FLOW TOWERS ... Highly func tional with conservative, highly efficient spray distribution. Choice of caring materials will fit any architecture--may be installed inride of masonry enclosure with louvered openings. Low cost, space saving tower with .very high performance record. This tower is particularly useful for high efficiency designs. Cast aluminum variable pitch multi-bladed fans are supplied. Bulletin LM-455 LILIE-HOFFMANN NEW WATER-MASTER COOLING TOWER ... Steel packaged units distributed by dealers. Built to Lilie-Hoffmann high standard quality with heavy duty motor. Standard equipment in cludes air inlet and outlet screens. Have many years of. built-in mainte nance free operation with a high performance record. Size from 3 to GO ton --shipped assembled. Large units are easily disassembled for special handling. Bulletin WM-757 - LILIE-HOFFMANN HORIZONTAL DRAFT PACKAGE TYPE TOWER ... Designed for 4 to 100 ton air conditioning and refrigeration installations. Side walls are of corrugated and/or fiat cement asbestos with stainless steel trim. Long service life with no printing problem means con servative operation. All towers equipped with either 4 or 6 bladed, deep pitched, low speed fans for delivery of maximum air at minimum horse, power and low decibel rating. Bulletin CUS57-5M LILIE-HOFFMANN INDUSTRIAL INDUCED DRAFT TYPE ... A very heavy duty tower providing the-maximum in high efficiency for large capacities. Designed with conservative ratings. Provides independent operation of individual cell or group of cells. Cells can be arranged in-line or back to back. Pumping head design is low.installations are world wide. Bulletin MD-94-Z LILIE-HOFFMANN ATMOSPHERIC SPRAY TOWERS ... Manu factured in two models. Smaller CS series for air conditioning and refrigera tion up to 50 tons which are distributed by dealers. Larger S series for heavy duty and large capacity industrial installations. Heart quality red wood throughout. Galvanized wrought iron headers with bronze non clogging spray nozzles supplies on both models. Completely prefabricated with simple instructions for easy erection. Bulletins CS and S.. l i Air System Equipment Cmiiu t THE MARLEY COMPANY 222 W. Gregory, Kansas City 13, Missouri tpic(i)to>|yM in All Principal CUie* (Comull Qatililtd Phon* Directory) Wafer Cooling Towers of AU Types and Capacities. Spray Nozzles 183 m HARLEY DOUBLE-PLOW AQUATOWER HARLEY UNDERFLOW AQUATOWER MARLEY AQUATOWER HARLEY PBRMATOWBRS - CODHTER-FLOW STEEL MARLEY DOUBLE-FLOW AQUATOWER ... For performance --and professional acceptance . . . there is nothing like the Double Flow Aquatower in the intermediate-capacity cooling field. This "low silhouette," low pumping head cooling tower is designed for air condi tioning and refrigeration jobs of 50 tons or more. It has open gravity water distribution, full height louvered walls and all fittings and me chanical equipment are readily accessible. Available in wood or steel structure with asbestos cement board casing and in single or multi-cell arrangements. Write for Bulletin DFA-58. MARLEY UNDERFLOW AQUATOWER . . . First intermediate capacity cooling tower with no louvered sides or ends. Mechanical equipment is located beneath tower which inherently baffles operating sounds and facilitates inspection and service. Structural framework of steel cold water basin acts as grillage; only corner support columns required. Hot water basins at top are covered, leaving minimum air discharge area at ends exposed from above, greatly increasing firesafety. Casing and basin covers asbestos cement board. Write for Bulletin UA-58. MARLEY AQUATOWER . . . Available in a complete range of 11 sizes, rated for servicing from 3 to 60 tons of air conditioning or refrig eration. Thousands of steel packaged units have proved themselves in years of maintenance-free operation. They are stocked by dealers throughout.the country--are shipped completely assembled and re quire no "field construction. Large units may be readily disassembled for easy handling. Write for Bulletin AQ-58. MARLEY. PERMATOWERS ... Available in II sizes, are the newest packaged cooling towers designed for maximum resistance to corro sion. They combine the time-proved design principle of Marley double flow cooling with many new design features, including all-plastic water distribution piping assembly, plastic depressed sump, plastic fan cylin der, resin-impregnated-fiber surfaced laminated casing and basins. Write for Bulletin PT-58. MARLEY COUNTER-FLOW SERIES, STEEL AND WOOD . : ; This new series of Marley counterflow cooling towers is designed especially for heavy duty air conditioning and refrigeration service. The all-steel model (with corrugated asbestos cement board casing) is designed to meet fire codes in all metropolitan areas. Both the steel and wood models blend well with modern architecture. May be installed with any combination of louvered walls open providing unusual flex ibility and maximum utilization of usable space. Write for Bulletins CS-58 and CW-58. MARLEY CROSS-FLOW . For large capacity industrial cooling, . Marley offers 2 towers that utilize the patented Marley Cross-Flow principle--The Double-Flow and Single-Flow. Write for Bulletin CF58. MARLEY SPRAYTOWERS... Complete line of all-redwood natural draft cooling towers; capacities from 2 tons up. Write for Bulletins ST-58 (up to 35 tonsJ 200-58 (above 35 tons).  184 Air System Equipment c^bi r ingTowerCo,lnc. -220 DUPONT ST., BROOKLYN 22, N. V. HEADQUARTERS FOR COOLING TOWERS Counterflow Type Towers available with either redwood or steel framing. Steel framing members are all hot dipped galvanised after fabrication in accordance with ASTM specifications. Partitions, louvers and siding of ce ment asbestos board are standard on this type of tower. . Series "DA" towers are available in California redwood, or Hot Dipped Galvanized framing. Corrugated ce ment asbestos board casing, laid horizontally, is fastened to frame with Galvanized bolts and Neo prene washers. Slipfit louvers of flat cement asbestos board provide easy access. All hardware is Hot Dipped Galvanized. Corrosion Resistant Hardware. Aluminum or Stainless Steel Fans. Nailless Redwood Filling Removable at Tower Base. Nailless Three-Pass Redwood Eliminators. Removable Louvers. Air System Equipment Sw Monarch Manufacturing Works, Inc. 185 2509 E. Ontario St., Philadelphia 34, Pa. SPRAY NOZZLES FOR WATER AND OIL NON-CLOG AIR WASHER NOZZLES Produce an exceptionally efficient, evenly distributed hollow cone spray. Single large tangential inlet to swirling chamber minimizes any possibility of clogging. Also available in Ys in. to 1 in: pipe sizes inclusive, and of Brass, Stainless and Monel. Water Capacities: Gallons per Hoar Pipe Size and Fig- No. Orifice Lead Operating Pressure: Lb per Square loch J 10 20 20 40 60 so too X inFig. 629 or 69 61 61 53 49 69 2.7 3.3 3.8 4.7 5.4 6.0 61 4.2 5.1 5.9 7.2 8-3 9.2 53 2.7 3.7 5.3 6.5 7.5 9.2 10.5 11.8 53 4.0 5.7 8-2 10.0 11.5 14.1 16.3 18.2 49 5.6 7.9 11.1 13.6 15.7 19.3 22.2 24.8 X in. Fig. 629 or Fig. 631 Hi X X X 1Xa Xs 9.6 13.5 19.2 23.4 27.0 33.0 38.4 42.9 Hi 12.2 17.3 24.4 29.9 34.6 42.4 49.0 54.9 Xa 14.6 20.6 29.1 35.7 41.0 50.4 58.4 65.1 X 15.9 22.5 3I.IT 39.2 45.1 55.2 .63.7 71.5 X 21.7 30.6 43.2 53.0 61.1 75.0 86.4 98.0 Fig. 631 Fig. 629 AIK CONDITIONING AND OIL BURNER NOZZLES Water Capacities: Gallons per Hour Ncsric fJo. Operating Pressure, Lb per Square Inch 25 40 60 so too Min. Freesme (PSI) 1.35 1.65 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 6.00 7.00 1.00 1.30 1.50 1.90 2.20 2.40 2.60 3.00 .57 .75 .94 1.13 1.27 1.64 1.90 2.40 2.78 3.04 3.28 3.SO .70 .92 1.14 1.39 1.55 2.01 2.33 2.94 3.41 3.72 4.03 4.65 .81 1.06 1.32 1.60 1.79 2.32 2.69 3.40 3.94 4.30 4.66 5.37 .90 1.18 1.49 1.80 2.00 2.60 3.00 3.80 4.40 4.80 5.30 6.00 40 40 . 35 30 25 25 20 20 20 15 15 15 Produce very effective breakup with direct pressure only. Capacities above are on .water. "Nozzle No." is capacity on 34 second Saybolt vis- X cosity oil at 100 lb pressure. Larger sizes up to 60.00 gph and smaller sizes down to 0.60 gph. Furnished of all Brass for Water--Stainless Steel tip and disc for Oil. Standard with Vs in. or Va in. female or Va in. male pipe Brass adapter and Monel gauze strainer. . SPRAY POND NOZZLES For recooling condenser water, etc. Operate on pres sures from 5 lb upward. Made of Cast Red Brass and . in pipe sizes Va in., 1 in., V/t in., 2 in., 2Vz in. and 3 in. Capacities from 41 to 134 gpm at 7 lb pressure. Write for Detailed Catalogs  Hot Transfer SerfMe Aerofih CvrffOrOtiOti 187 Available in a wide range of sizes and types for heating, cooling, air con ditioning and process, Aerofin is die modem standardized light-weight encased fan-system surface designed by fan engineers to meet present and future requirements of this highly specialized field All standard Aerofin units are furnished as completely encased units, ready for pipe and duct connections. The patented casings are built of pressed steel and are exceptionally strong and rigid to protect the unit from all strains of pipe connections and expansion or contraction in service. The casings are flanged on both faces, top and bottom, and templatepunched for bolting adjacent units together or for easy duct connection. Guarantee Aerofin is guaranteed, when properly installed and operated at pressures and temperatures not exceeding those specified, against failure or leakage due to faulty material or manufacture. The Aerofin Corporation will fur nish a new unit fob car Syracuse, N. Y., or Kingston, Ontario, for replace ment of any unit found defective in either material or workmanship within one year from date of shipment of original unit, when such defective unit is returned to the factory at Syracuse, N. Y., or Kingston, Ontario. Extended Surface Exclusively Aerofin manufactures light-weight extended-surface heat exchangers ex clusively -- not as a side line or accessory. Modern manufacturing, research and engineering facilities give real meaning to the Aerofin guarantee. Aerofin ratings are accurate -- units may be safely installed to the full rated capacity. Aerofin heat exchangers are rated accordingto accurate research labor atory test data and operate effi ciently at full rated capacity. Smooth-Fin Construction Provides Greater Capacity -- Less Air Resistance . With air resistance and turbulence caused by die corrugations in the.old- style fins now eliminated, note how many more fins can be used per inch of tube length. Note the extremely low air friction of this new design. x For optimum service, aluminum fins are spaced 14 fins per inch; copper, 12 fins per inch. Because of the low friction losses, high air velocities are entirely practical. This, combined with maximum.heat transfer per sq ft of face area, results in extremely high heating or cooling capacity in relation to the available space. ' For lower temperature differences, the tubes can be spaced on wider centers as required, or fewer rows may be used. Aerofin Tapered Fin The wide contact base of the new Aerofin tapered fin conducts suffi cient heat between fin and- tube to make the entire fin effective transfer surface. It is not necessary to crimp the fin to provide the required con tact surface. . Conventional Straight Fin The relatively small amount of heat conducted by the small contact sur face means that only a portion of the fin is effective heat transfer surface. Such fins are generally crimped to provide greater contact surface. * i i ! I j 1 ii  188 Air System Equipment EADING TUBE CORPORATION Empire State Building, New York 1, N. Y. Plant: Reading, Pa. READING, PA. WOODSOK, L.L, N.Y. 57-17 Northern Bhed. PHILADELPHIA, PA. 921 Penn SL Distribution Depots: CHICAGO, ELI. 305 W. 31st SL ATLANTA, GJL 0 Morphy Ave. OAKLAND, CALtF. 410 Hegenberger Road curajum, oato tE15PrtteA. B los akgeiis, cauf. 120 No. Santa Fe Ave. Sold Through Wholesalers Only DALLAS, TEXAS 9000 Sovereign Row Brook Hollow Industrial District HOUSTON, TEXAS im.Rotfiwed SL READING "UfCTMStAL COPPER REFRIGERATION TUBE Reading refrigeration tube is made to the highest standards. Composed of 99.90% pure deoxidised copper, every coil is thoroughly dehydrated and sealed at the mill before being packaged. Its immaculately clean in side surface is the result of the most modem production methods and exhaustive inspection operations. All sizes of refrigeration tubing are regularly shipped in 50 foot lengths. Coils are individually packaged in side master shipping cartons. ACTUAL OUTSIDE DIAMETER WALL THICKNESS, INCHES LBS. PER LINEAR FOOT WEIGHT PER 50 FT. COIL NO. COILS TO MASTER CARTON TOTAL FEET TO MASTER TOTAL NET WT,, EA. MASTER W .030 .035 1.74 10 500 17.4 .030 .058 2.88 10 500 28.8 Ya" .030 .080 4.02 10 500 40.2 .032 .109 5.45 10 500 .54.5 .032 .134 6.70 10 500 67.0 W .032 .182 9.10 5 250 45.5 W .035 .251 12.55 5 250 62.8 .035 .305 15.25 3 150 45.8 MACKENZIE WALTON SMALL SEAMLESS QUALITY PRECISION TUBING in Copper and Copper Alloys ' ' Famous for Accurate and Fine Finish Tubing Quality Controlled from.Start to Finish Produced to Your Exact Specifications CAPILLARY SHAPE CAPILLARY--Available in coil and straight lengths from 0.031 in. OD to 0.250 in. OD and 0.009 in. to 0j055 in. in wall thickness, depending upon alloy and form specified. We guar antee uniformity of size, cleanliness and smoothness of bore, and consistency of temper. Modern methods and equipment under constant control by skilled metallurgists, assure quality from start to finish. - ' SHAPE--Whatever shape you specify . . . rectangular, square, oval, fluted, reeded, embossed, specialty or architectural, all Mackenzie Walton shape tubing is produced to meet the most exacting requirements. Available to your specifications within. our size range in copper and copper-base alloys in random mill or exact eut lengths. Consult us on all applications. THIN WALL--Available in Copper (DHP or OFHC), Brass (70/30, 85/15, 80/20), Bronze (95/5, 90/10) and Nickel Silver (18 percent, 15 percent, 10 percent) in size ranges from in. to % in. OD, and wall thickness 0.007 in. and upward, de pending -on alloy and form specified. Noted for fme quality and cleanliness of OD and ID, our thin wall tuning is always made to close tolerance. BRAIDED--Where armor or reinforcement of capillary tub ing is an important factor, we will braid to your requirements. Choice of B 4 S wire gage size in eye-appealing copper, tinned copper, stainless steel, galvanized steel, ana aluminum with one to four layers over capillary tubing from 0.031 in. to 0.125 in. outside diameter, in wall thickness from 0.009 in. to .040 in. BOURDON--Our Bourdon tubing assures you absolute, min imum tolerance variation for instrument accuracy. Quality controlled through rigid inspections means consistent spring properties, accurate size ana constant wall thickness. We can furnish six standard size groups In random mill or exact cut lengths, in wall thicknesses from 0.0039 in. to 0.068 in., or to your specifications. . THIN WALL BRAIDED BOURDON TUBE CORPORATION Empire State Building, New York 1, N. Y. Plant: Reading, Pa. READING, PA- W00DSIDE, LL.N.Y. 57-17 Northern Blvd. ptnUDoran. pa. 321 Penn St Distribution Depots: CHICAGO, Rl_ 305 W. 31st SL ttEVELANO, OHIO ,615 Pe,kms ak. - ATLANTA, GA. 690 Murphy Ave. ** W- Unit 5. Bldg 6 2S45 Walnut St OAKLAND, CALIF. IlQRegenberger Road LOS ANGELES, CAUF. 120 No. Santa Fe Ave. Sold Through Wholesalers Only DALLAS. TEXAS 9000 Sovereign Row 8rook Hollow Industrial District HOUSTON, TEXAS 1121.Rothwell SL READING "READI-FIN" Type W/H IS EASILY FABRICATED beam.TM j TTiat same nigged construction and design that gives Type W/H finned tube its high performance characteristics, also readily lends itself to being coiled, bent or formed into the particular type of bundle you desire. This feature is important- Since the fins are an integral part of the tube, any bending or coiling does not affect the strength of the concentricity. The performance remains high and the durability' lasting. "Readi-Fin" Type W/H is available in the "as finned" or "annealed" temper. Annealed temper is suitable for bending. . TrBcuoTeaalfiaMila*--"BodJ-PIo-type W/B Type 1-AU.Oaiwd tube Type B- Do<h ends ptafn "READI-FIN" INTEGRAL FIN TUBING SPECIFICATIONS FINNED SCTKm JI4-J2* 4*5-.4*5 -J7*O4--.7i*4 11-Rn Tubing Spotiflcotions 442-070 AK-,07* .774-775 iJ3-W 4J2200--1J30 IM4A3 J* X25--ou X2*-473 435-441 READING READI-FIN Type S/T EXTENDED SURFACE CONDENSER TUBE "Readi-Fin" Type S/T--the extended surface condenser tube--is designed pri marily for' shell and tube heat ex changers. Tube ends may be finned, stripped or plain. The outside diameter of the plain end is approximately the same as the outside diameter of the fin. "Readi-Fin" Type S/T, with plain ends, is fabricated in shell and .tube heat ex changers in the same manner as plain condenser tubing. "Readi-Fin" Tlyypj e S/T is available in "as finned" Type S/T Condenser Tubing neaied" tempers. The "as finned" temper has plain ends suitable for rolling-in operation. The "annealed" temper is suitable for bending. iiim ix i OWJieUtfr** U It H .N a aa "READI-FIN" INTEGRAL FIN TUBING SPECIFICATIONS--19-Fin Tubing NCaauBfau 22*t4m* 5*42 i)5***M4*6*5>*)B MJmmmNO1tju 5M*4330 MMOU MnuMs* a *14134 CND { ..A*t*nt7*--s-5mm05) 00--115C)CCCwcueMMu*vwp*c*ctrrhBr*a" 444222222---4442225** 422-(21 COCOuwW*Ppmr*rr ' U-lfird1ta *t*5i5---t11s)) fMUt*4 BBBrrraaa .......777727774444444477772277----------.777777225))J))5)155515)) 5E UO--li)j'fMtZTbkuar J72-I7I 4s.*77n25-----j44m77** 472-47* CQ*a**r 4O5--15lfSMTBtrraa ....4*****7***77777-----11111.4X40400000573)) nWuaBa 4444434*5-----40075M02 44444544475S*4554--------4B40o077BJn0055) 44444444.447*54)7)5525554555------------40444004174745905032100*4* 4444**40255----0-14400*4470* " 444-472 WJ-IOO m*92--x4i*)7 Ft704ED SECTION Fi O D. Im 014. nwUaa ..,44*0**44-----**77H22 4444A400111l7l11*5--------444444111411777777 .........277777777137553555444444444---------77777777744444444*222222222 444.04M46111------J44144447777 ..J.,****t*0**t644--*--7-***m***2222 .J.J54447N7---JJ317M** .4.4.444*B***24444------555J50000044444 444444441111111177777***-------------4444444C2222222******** ...J77244444424----T7775555444* 44444*444----4117774** 444477---4*77** J2i-tii 44O4443J*r243*3------14000443J45J*123~1 `4.444.44O0445*7*)B453152*O---------400-0O40O4553rUXWS42)* 4*4-032 445-44* 444714--00*45* JilI22 ....444400005555 ..44**44 AA.4H*H4 AH JSUtt JH 471 474 AH aBO*aohdUaelao* Se. T4AJ42 j-o*r- ----1j433..4.31nM4*---.-- 54iJJU4J*N722 . 5J4U5.4J454*i0* S3JJI* As44Xu0* -. SA5t1St)*" J*1 1x4 544 "T3353444J4745J* ' ' s.7s0*r- .75* READI-FIN -.---14I44B031-- BIT 1MX05  190 Air System Equipment * nat Tnia The G & O Manufacturing Company 140 Winchester Avenue New Haven 8, Connecticut INDIVIDUAL AND STRIP FIN TUBING We manufacture a complete line of high efficiency heat transfer surfaces in a wide range of standard sizes with individual square, round and oblong fins. The use of individual fins permits using fins in groups at intervals along the straight,length of any tube for the manufacture of U-bends, continuous return bend, and spirally wound coils. Where space permits, the use of square or oblong fins provides proportionately greater surface than a round fin of a diameter equal to one side of the square or oblong fin. G&O Individual Fin Tubing is available for heating coils of every description, including unit heaters and blast coils, intercoolers, aftercoolers, baseboard radiation, and convector elements. STRIP FIN TUBING Continuous strip aluminum fin tub- ing is particularly suited for cooling and air conditioning coils. The light- weight all aluminum construction is of advantage in installation where weight is an important factor. Vari- ous fin spacing is available and sec tions can be stacked to provide any practical number of rows in direc- tion of air flow within the limits of maximum height and width area dimensions. - G&O continuous strip fin coils are produced in two standard sizes: 46 in. OD tubing with Vs in. wide continuous strip fins, or Y$ in. OD tubing with llf{$ in. wide continu ous strip fins. . . ' . . . INDIVIDUAL FIN TUBING standard SIZES Tube Fin Site Fin Surfaceper per Incb Linear Foot H' K" H" y* ys w H' I* m* %' sq Ui' r'd \H' r'd 1^'sq IK' Sq q m* q 2Kr q 6 0.80 sq ft 6 0.87 sq ft 6 1.55 sq ft 6 2.40 sq ft 7 Z95 sq ft 6 4.15 sq ft 5 3.50 sq ft 6 4.00 sq ft 6 -3.82 sq ft RADIATING ELEMENTS FOR ALL HEAT TRANSFER PURPOSES ARE AVAILABLE IN A WIDE RANGE OF SIZES Air System Equipment tw Trmf, The Patterson-Kelley Company, Inc. 191 101 Burson Street East Stroudsburg, Pa. New York 17 101 Park Avenue Philadelphia 3 Boston 16 . 700 Walnut Street 96A Huntington Avenue Representatives in Principal Cities Chicago 4 Railway Exchange Building FIG. 1--Exclusive P-K aluminum fin is designed for optimum heat transfer and vaporization. and more. FIG. 3--P-K "Internal Fin" dry expansion Freon cooler installed on Worthington packaged water chiller. Package system -designed for air conditioning. FIG. 4--P-K dry expansion Freon chiller installed on Worthington packaged air chiller. FIG. 5--P-K "Internal Fin". dry expansion Freon cooler installed on Chrysler Airtemp packaged whis key chiller. FIG. 6--Insulated 4 circuit "Inter nal Fin" Freon chiller. Continuous Strip Pin. All Aluminum Cooling Coil . . Continuous Strip Fin All Aluminum Heating & Cooling Cod FIG. 8--P-K storage water cooler designed for process liquid cooling and chilled-water services. . 7--P-K single circuit dry ex pansion Freon cooler. Cooler is de signed with plain tube and remov able "U" tube bundle.  192 Air System Equipment > SL, THE KITTLING CORPORATION 103 Kentucky St. Buffalo 5, N. Y. REPRESENTATIVES IN PRINCIPAL CITIES * Prompt delivery from strategically located warehouses RITTLlNG Heating and Ventilating equipment includes a complete line of finned tube units for residential and nonresidential application; Wall and Baseboard Radiation, Convector Radiators, Unit Heaters, Back Draft Dampers, Air Cooled Condensers. Engineering and rapacity data is included in catalogs mailed on request. KITTLING FINNED TUBING Steel tubing in 1 in., IK in., and 2 in. IPS sites. Steel tubing is supplied with steel fins. Copper tubing is available with 1 in. and lK in. nominal sizes with aluminum fins. Catalog FTSS. RITTLlNG 1200 HEAVY DUTY BASEBOARD Heavy sheet steel cabinets with louvered inlet and outlet grilles. Designed for semi- recessing. Available: with 1 or 2 heating elements for high output in short runs. Catalog BBSSA. . RITTLlNG SIL-VECTOR . Attractive enclosures with rounded top, bottom, and ends. Outlet louvers located at top and front radius. Die formed louvered inlet panel at bottom provides strength, rigidity, and integral support for front panel throughout its entire length. Catalog FTSS. . KITTLING SIL-N-WALL Top of cabinet takes place of window sill. Front takes place of plaster finish under windows where unit is installed. Sizes fit standard window designs. Variety of beating elements in single, double, and triple height to provide needed output. Length and height as required. Catalog FTSS. RITTLlNG 483 BASEBOARD RITTLlNG 485 Baseboard is only 6JKa in. low and projects 2He in- into the room--only lK in. when recessed to the depth of the plaster. Ideal for installation under picture windows. One-piece back plate has integral top and bottom cover. Covers are finished in neutral prime. Adjustable damper can be easily installed at any time. Catalog BB-48S. KITTLING SCHOOLMASTER UNIT VENTILATORS Are complete heating and ventilating units with heating elements, circulating fans, air filters, and dampers to control te fresh air volume. Steel cabinets, available in five sizes, have baked-oa enamel finish in a choice of colors. Catalog UV-11S7. MATCHING STORAGE CABINETS. Heavy steel cabinets match Schoolmaster Unit Ventilators to form an.unbroken line when joined. Available with and without concealed heating element. Also furnished with locking doors. ASK FOR YOUR COPY OF CATALOGS. ,, . . 4 x .. ,____ . .... . . . ., RITTLlNG BASEBOARD RADIATION. RitUing offers a complete line of fabricated steel baseboard radiation in five basic types to meet every requirement of residential and non-residential specifications. Wide choice of heating elements and enclosures provides sizes and designs to fit every installation condition. Catalog BBS6. ' ` OTHER RITTLlNG PRODUCTS, NOT SHOWN, INCLUDE: WALL RADIATION CABINET UNIT HEATERS UNIT HEATERS CABINET CONVECTORS SPACEMASTER HEATING AND VENTILATING UNITS BACK DRAFT DAMPERS . Air System Equipment RSgff-- Curtis Manufacturing Company Refrigeration Division 1959 Kienlen Ave. St. Louis 20, Mo., U.S.A. 193 NEW YORK OFFICE 30 VESEY ST. CHICAGO OFFICE 9 SOUTH CLINTON ST. REFRIGERATION AIR CONDITIONING Complete Line of Units from 34 to 100 hp. Unit Coolers, Air Handling Units, Evaporative Condensers and Cooling Towers. Air Conditioning Equipment, Packaged and Central Types. Complete Refrigerating Equipment for Dairies, Cold Storage Locker Systems, Walk-in Coolers, Drinking Water Systems, Commercial and Low Temperature Cooling and Processing. Combination air and water cooled Condensing Units. K through 3 hp. COMMERCIAL REFRIGERATION Air cooled condensing units from J4 U> 3 hp, inclusive, combination, air and water cooled units from % to 3 hp, inclusive, and water cooled units from ^ to 100 hp,- inclusive. All models charged with Freon 12 re frigerant. Mechanical ..advantages include Timken Bearings, Positive Treasure lubrication. AIR CONDITIONING 15 hp Cleanable Shell and Tube Condensing Unit. Other sizes from <K to 100 hp. Air cooled condensing units with various types of ^matching coils can be added to present hearing system. Water cooled units can be supplied with air cooled condenser. Water cooled units adaptable for hearing. uguuung UDU8, 3 to 100 tons. 3-5-7K*lO*15 and 20 Ton Packaged Type Air . Conditioner 25-30-40-50 Ton Packaged Air Conditioners Air Cooled Type 3-5-7K Tons 7K to 100 ton Packaged Liquid Chillers  194 Air System Equipment Uelriscrsiiss Mecfciaory DOLE REFRIGERATING COMPANY 5918 N. Pulaski Road, Chicago 46, 111. 103 PARK AVENUE, NEW YORK 17, N. Y. Canada: Dole Refrigerating Products Limited, 29 Brock St., N., Oakville, Ontario EXPORT DIVISION AND NEW YORE BRANCH--C- C. Ryan 102 Park Avenue New York 17, N. Y. Phone: MUtryhfll W693 NORTH BAST-C. J. Tew 55 Webster Street Saratnta Sprincs. N. Y. Phone: *783 ATLANTIC CENTRAL--A. J. LANE 628 St. Oeorte Read Raleifh, North Carolina Phone: TEmphs 2-8932 SOUTH EAST--D. A. DeMore 2518 Pineview Drive Decatur, Georgia Phone: Drake 3-1140 DOLE DISTRICT MANAGERS CHICAGO--H. DeBao&b 5910 N. Pulaski Road Chicago 16, lUiaraa . Phone: IRring 84442 NORTH CENTRAL--A. W. Monroe 6910 No. Pulaeki Road Chicago 46, Illinois Phone: IRviag 84442 . EAST CENTRAL--A. B. Brady 467 Melrose Avenue Columbus 2, Ohio Phone: AUberet 2-5255 SOUTH CENTRAL--J. A. Wilfcenea 7241 Canterbury Drive St. Louis 21, Missouri Phone: EVergreea 1*1781 SOUTH WEST--R. H. Tafel 10347 Plummer Drive Dallas, Texas Phone: BRoadway 94282 PACIFIC SOUTH WEST-H. E. CUy 1437 8. Los Angeles Street Loe Angeles 16, California - Phone: Richmond 74121 PACIFIC NORTH WEST--R- L. Ballinger ' 603 Maritime Building Seattle 4, Washington Phone: Main 1-MSS CANADIAN BRANCH Dole Refrigerating Products Limited 29 Brook Street, North Oakville, Ontario Ray F. Kempt. Manager Gordon L. Timb a, Saks Representative - MANUFACTURERS OF AIR CONDITIONING AND REFRIGERATION EQUIPMENT ICE-CEL ACCUMULATOR UNITS LATENT HEAT ICE STORAGE SYSTEMS FOR AIR CONDITIONING EXTERIOR ICE.CEL TANK ICE-CEL INTERIOR X-UNIT APPLICATION DOLE ICE-CELS are used wherever the air-conditioning load is high for a relatively short period of time, such as in churches, mortuaries, auditoriums, lodge halls, cafe terias, offices, theaters, motels, retail stores. OPERATION The ICE-CEL consists of an assembly of DOLE Vacuum Plates submerged in a tank of water. A condensing unit is connected to and refrigerates the plates, causing ice to build up on their surface. A control is available to stop the condensing unit when the ice has reached any desired thickness. When cooling is to begin, chilled water from the ICE-CEL is pumped through a water coil in the air stream. In passing over thi coil, the air gives up its heat to the water which is then returned to the ICE-CEL for re-chilling and re-circulation. HOLDOVER CAPACITIES AND BUILD-UP TIME FOR STANDARD ICE-CEL UNITS STANDARD LHS-12 LHS-21 LHS-31 LHS-M ICE-CEL UNITS or LHS m LHS 2lx LHS 3lx T-TT^ Jlx Hold- inlet water temp. 45* 18 T.H. 89 T.H. 43 T.H. 81 T.H. 40* 17 T.H. 31 T.H. 47 T.H. 77 T.H. 34' 18 T.H. 24 T.H. 36 T.H. 60 T.H. Comp. HP S w e tE m aes m 6 s H HP 1 HP m HP 2 HP 2 HP 6 HP 7HHP JO HP IS HP 20 HP 19* 17* 12* 25 r 30 8* 15 U 10 19* 16* ir 1* 20* 16* 29 10* 20 - 4* 15 0 13 10 9 NOTE: Add 10 parent if starting water over 60 deg Add 6 parent If starting wata between 40 deg-60 deg. 8.T. indicates approximate tuetkm temperature at end of ice buildup. Condensing units smaller or * larger than shown not recommended. COMPRESSOR REQUIREMENTS Since the compressor capacity can be spread over the whole day, if necessary, rather pnn just for the duration of the actual cooling period, a much smaller condensing unit, together with a correspondingly smaller cooling tower or evaporative condenser, can be used. This eliminates the need for water economisers. Also a compressor used for other purposes and not needed full time can have its idle periods devoted to build ing up ice on the ICE-CEL to be used while the compressor is doing its regular job. As a result, operating costs are kept at a minimum, especially in areas where demand power rates are in effect. The existing power service to the building is usually ade quate. ' ENGINEERING SERVICE Complete' Engineering Catalog BAE and further technical information avail- ' able on request. Our staff of engineers will help you with your refrigeration problems at no charge or obligation. A DOLE application engineer is located near you to give you prompt service. Write, wire, or phone. .* l . w * * |m | ss==a | 1SSS5= Air System Equipment (utriguwang Hr-^nmy Atlanta 3, Ga. Boston 15, Mass. Buffalo, N. Y. ClIARLOTTB 2, N. C. Chicago 6, III. Cincinnati 2 Ohio Dallas 1, Texas Kansas City 8, Mo. Los Angeles 14, Calif. Memphis 3, Tenn. New Obleans 12, La. Frick Company New Yore Citt 17 Oblando, Fla. Waynesboro, Penna. Palo Alto, Calif. San Francisco 4, Cauf. (sub-branch) Seattle 1, Wash. (sub-branch) Distributors in Principal Cities Air Conditioning, Refrigerating, Ice Making and Food Freezing Equipment e 195 Philadelphia 4, Penna. Pittsburgh 22. Penna. St. Louis 3, Mo. Washington 5, D. C. Unit Air Conditioners, 3. 5, St hp. AIR CONDITIONING Complete Frick systems, including original designs, in all sixes: also refrigeration for use with equipment supplied by others. Thousands of installations, the world over, attest the value of Frick air conditioning, which has 50 years experience behind it. See Frick Bulletin SOS on hospital work; 60S on in stallations and systems; Sit on unit conditioners; and tifi on Frick air conditioned storages, which are revolutionising the cold storage industry. Estimates cheerfully furnished. Frick "ECLIPSE" Compressors, 2, 3, 4, 6 or 9 cylinders. LOW-PRESSURE REFRIGERATION Bulletin 100. Small commercial units, "ECLIPSE" multi-cylinder com pressors, and larger heavy-duty enclosed compresors, handling refrigerants 12 or 22, provide a complete and efficient line to meet your exact needs. We build unit sir conditioners, central systems, plain and finned coils, water coolers, condensers, con trols, valves and fittings: no job too special for Frick Engi- Combined Units AMMONIA REFRIGERATION with "ECLIPSE" Com pressors. Bulletin 100. . ' Heavy-duty vertical compressors, with 2 or 4 cylinders, in sixes from 2n to 1000 tons of refrigeration: handle refrigerant 22 equally well. Useful life of these dependable nmghinn aver ages 40 years. Highly economical for cooling water on air condi tioning, and for neat-pump service, in addition to regular re frigeration duty. Booster systems, developed by Frick Engineers 30 years ago,-provide power savings at low temperatures. "ECLIPSE" compressors, with 3, 6,.or 9 cylinders, aln supplied for ammonia work. Heavy-duty Industrial Compressors, 3 in. by 3 in. to 17% in. by 12 SERVICE in. Bulletins 112, 514 We supply the most complete service, including recommenda & 651. tions, estimates, design, manufacture, installation, test nH maintenance. One responsibility, one superior standard. Quota tions cheerfully furnished through Branch Offices and world wide Distributor organisations. The Two Office Buildings of the American National Insurance Co. at Galveston, Texas, are Air Condi* tioned Throughout with Frick "ECLIPSE" Conti Low Pressure Refrig erating Units, Open ` ` ;ible- The Barnes Hospital--Washington University Medical Center, at St. Louis, has Eleven Frick Air Condition ing Units and 42 Frick Compressors on various Cooling Services. Four of these Frick ``ECLIPSE" Compressors were used over 17 years for Air Conditioning the TVA Offices in Knoxville, Tenn. Replaced with Four New "ECLIPSE" Machines.  196 Air System Equipment Cm ami OO THE READY POWER CO. NATURAL GAS PACKAGED AIR CONDITIONERS DETROIT 14, MICHIGAN GENERAL DESCRIPTION--Ready- AUTOMATIC OPERATION--All Power Air Conditioning Units combine modem, Freon compressors with medium-speed industrial-type gas en gines. These packaged gas air condition ing unite are performance-tested under actual operating conditions to insure long, trouble-free, service. These units operate on clean natural gas. Ready-Power Units are available with either Thermostat Start or Push-button Start Controls. All models are equipped with a-c electric starting motors and automatic LOAD-MATCH capacity con trols. .- Thermostat Start Units start and stop automatically in response to the setting of your thermostat. Push-button start Engine carbon deposits are nearly non units must be started and stopped existent. These natural gas-carbureted manually. engines last 3 to 5 times longer than similar engines operated on gasoline. AUTOMATIC CAPACITY CON . TROL--Automatic Capacity Control is OUTSTANDING ECONOMY--Less than 13 cu ft of low-cost natural gas is required per ton hour. Fuel consumption achieved by varying the operating speed and by unloading compressor cylinders after the unit has dropped to the mini mum operating speed. This means that is in direct proportion to the actual load the pumping rate of the compressor is throughout over 80 percent of the capac exactly matched with the cooling load. ity range. A power take-off pulley is provided on the engine shaft to providfor belt-driven tower pumps- The econ omy combination of low fuel require ment, engine-powered tower circulation, In this manner, maximum operating economy is realised. This "LOADMATCH" capacity control system permits almost continuous com pressor operation at a constant evapora tor coil temperature, the result of whieh ftnH "matched to the load'1 fuel con is extremely close control of humidity sumption makes Ready-Power out and temperature without the need for standing in net refrigeration costs. large re-beat systems. - PHYSICAL DATA ENGINE COMPRESSOR PACKAGED UNITS ENGINE-COMPRESSOR No. COMPRESSORS--Modern precision balanced Freon 12 and 22 compressors assure a minimum of vibration. The Ready-Power control system automat ically unloads compressor and permits start-up at idle speed with all cylinders unloaded. Approximately 2 to 3 minutes are required to fully load the compressor after start-up. This greatly decreases start-up impact loading on valves, bear ings, etc., and substantially increases compressor life over similar equipment operating at synchronous constant speeds of 1750 rpm or higher. COMPACT AND READY TO RUN-- Complete "packaging" of auxiliary con trols and accessory items with the direct driven compressor unit permits quick, easy installation in a space measuring only 3 ft X 7 ft. MATCHED WATER CHILLERS-- Ready-Power offers completely balanced and tested refrigerant systems for water- chilling applications. Matched chillercondenser units are designed to take full advantage of the variable capacity feature of the engine compressor units. The chiller and condenser are mounted on a heavy structural steel frame as sembly, completely piped and wired. A control cabinet houses the necessary related solenoids relays and switches' and other controls. LONG SERVICE LIFE--Powered by medium-speed industrial engines, these systems nave achieved an outstanding reputation for dependability and long service. The compressors represent the latest developments in design, engineer ing, and manufacture, and are longwearing and smooth-running. Units are equipped with automatic engine oil level controls and closed engine water cooling circuit. Nominal e . Refrismat Loftb--OmD Width--Overall Hcsxht--Owall Length of Baae Width of Baae Shipping Weight (approx.) UFt-onne no' *'i<r tv M$0 lb PHYSICAL DATA MATCHED CHILLER CONDENSER UNITS Chflfcr Model No. BCPS0 RCP25 ECPSO RCP40 RCPS0 RCP60 RCPM acpeo RCP1QQ RCPM0 RCP\ RCPltO Nonuo*! Capaest? Length Width Height . R^ippn| wt. Appro. ' SO T. 11* V 6* 1600 15 T. 11* 6* . Moo SOT. IS* V s* 1840 40 T. IS* I* 5* SOM 60T. 14* 3* 8* 3440 SOT. 13*6' 3* 6*0' 3740 05 T. 13* 3* 0' 4040 80 T. 14* 4' 8* 4900 IDOirT. 6* 8730 110 T. 15* 4* ` 8* 8730 130 T. 14' 4' 6' 8460 140 T. 14* 4* 7' 10000 This equipment data and information is included for convenience in rough analysis, layout, and application. It is not guaranteed accurate for final detailed design. For current design-information consult the nearest manufacturer sales office or your local Gas Utility Company. . 'Air System Equipment AxU Flow Aerovent Fan Company, Inc. Ash and Blade Sts. Piqua, Ohio Efficiency-engineered industrial fans and air handling equipment 197 DIRECT CONNECTED Heavy-duty units for industrial exhaust or air supply. Steel ring or panel orifice. Size 9 in. to 96 in. with 2, 4 or 6 blades. For capacities to 145,000 cfm. Also avail able in Extended Shaft and Pulley types. Write for Bulletin 100. EXTENDED SHAFT For high temperature, moisture or corrosive conditions. Ring or panel orifices. Sizes 12 in. to84 in. with 2, 4 or 6 blades. Capacities to 120,000 cfm. Bulletin 100. NEW "LS" FANS Belted and Direct Driven Ring, Panel or Duct types with new 4-blade "Macheta" Airfoil Propellers for peak performance at resistances to 1}A in. S.P. Sixes 24 in. to 48 in. for capacities to 46,000 cfm. Ask for Bulletin 750 and 776. PORTABLE UTILITY For personnel cooling, product drying and processing and fume removal. Ad justable for 180 degree discharge. Sizes 16 in. to 36 in. for capacities to 20,450 cfm. Bulletin tSO. SK- SEMI-PRESSURE FANS Standard units with new 7-blade pro pellers move more air with less power at resistances to 4 in. S.P. Sizes 14 in. to 60 in. Five types- Shown is "Bi-Flo" Duct Fan. Bulletin 400. VANEAXIAL Designed for maximum effi ciency and economy against resistances to 6)^ in. S.p7Highvelocity, straight-line air dis charge. Sizes 12 in. to 48 in. Capacities to 77,000 cfm. Bull. 450. AIR MAKE-UP UNITS Tempers and filters outside air entering working areas. Steam, hot water and gasfired types. Sizes 24 in. to 54 in. 2, 4 or 6 blades. Ca pacities to 45,000 cfm. Bul letin 850-875. CENTRIFUGAL BLOWERS For materials-handling, dust-collecting or exhaust systems. Reversible rotation. Adjustable discharge. 19 in., 28 in., 33 in., 40 in. and 51 in. wheel diameters. Bulletin 700. MANCOOLERS For spot cooling of men and machines, exhaust and general air circulation. Cradle, pedestal and 2 or 4-wheeled types. Portable, adjustable for 180 dis charge. Sizes 24 in. to 48 in. with 2, 4 or 6 blades. Capacities to 40,000 cfm. Bulletin tSO. DIRECT-DRIVEN DUCT Preferred by industry for high- velocity air circulation and ex haust of non-hazardous atmos pheres. Sizes 12 in. to 96 in. 2, 4 or o blades. Capacities ' to 145,000 . cfm. Bulletin 150. . ROOF VENTILATORS Three models, featuring rugged all weather construction with new low- level' design. Sizes 12 in. to 72 in. 2, 4 or 6 blades. Capacities to 93,500 cfm. Bulletin 600. LARGE DIAMETER PROPELLERS Adjustable-pitch aluminum alloy blades with cast alumimim hubs in 4 and 6 blade types and sizes 54 in. to 144 in. New AL-Metal propellers for cooling tower and heat exchanger applications in sizes 14 in. to 18 in. with 4 or 6 blades. Bulletins 500 and 510. BELT-DRIVEN DUCT - Recommended for handling dusts, fumes, vapors, high temperatures and hazardous atmospheres. Sizes 12 in. to 96 in. 2, 4 or 6 blades. Capacities to 145,000 cfm. Bulletin 160. PENTHOUSES Weather-tight enclosure for exterior mounted fans. Eliminates downdrafts; provides safe exit for fumes and vapors. Sizes 16 in to 72 in. Shutters optional. Bulletin 650. MEMBER AIR MOVING AND CONDITIONING ASSOCIATION (AMCA) Air deliveries of Aerovent equipment are determined in accordance with established and accented codes and each unit is guaranteed by the manufacturer to deliver rated performance. f 198 Air System Equipment Blwcra, DlSucn AIRFAN ENGINEERING COMPANY 7401 Telegraph Rd. Los Angeles 22, Calif., U. S. A. (Telephone RAymond 3*3354) 4-HEAVY DUTY BLOWERS Forward and backward curved wheels. Single inlet single width and double^ inlet double width. Wheel diameters range in size from 12 in. to 60 in. Any rota tion, discharge or arrangement. BLOWERS AND SCROLLS Made for original equipment. manufacturers of air handling units and evaporative condensers. Heavy duty riveted construction, center or end suspension wheels. 12 sizes; 10 in. diameter to 30 in. diameter, standard or hot dipped galvanized. <- STANDARD BLOWERS Medium duty blower assembly made in single or double width, sizes 10 in. to 30 in. wheel diameter, and features universal discharge arrangement. Motor mounting in any location. . - AIR WASHER EVAPORATIVE COOLER With slinger spray type water distribution system as part of packaged unit, assembled ready to use. Special , features of design insure high cooling efficiency and lower maintenance costs. Features such as fiber glass evaporative and eliminator filters washed continuously by efficient slinger spray. UTILITY FANS , For general ventilation, complete with weather-proof covers. Self contained package units ready to run, easy installation. 300 cfm to 20,000 cfm. Wheel diam eters 10 in. to' 30 in. Forward and backward curved wheels. AIR HANDLING COMBINATION UNITS ^ Offering a complete line of air handling and comfort conditioning units, utilizing direct expansion, water and steam coils for cooling and heating. Wide selection, both in vertical and horizontal arrangements. Capacity range from 1600 cfm to 35,400 cfm with special emphasis on quiet operation and thermal-acoustical insulation. * MULTIZONE AIR CONDITIONERS With the Heat Supplied by AGA Approved Gas Fired Furnaces from 200M-Btu to 1,200M Btu Input. -Available in horizontal and vertical arrange ments--Twelve sizes with capacity from 2500 to 35,000 cfm. Cooling coils from 6 to 60 square feet. Supplies air mixtures blended for simultaneous un equal heat load demands up to 25 individual zones from single unit. - Air System Equipment Blawcra lladdin^ 199 Heating Corporation 1111 West Avenue 137, San Leandro, California Manufacturers of Centrifugal Blowers, Heating and Ventilating Equipment BB FANS--Backwardly inclined blade fan with non-overload ing horsepower characteristic. Manufactured in 22 sizes, single and double width, all arrangements, 2 classes of con struction. Request Bulletin 605-A, 605-B. FC FANS--Forward curved fan, slow speed for quiet opera tion. Manufactured in 22 sizes; single and double width, all arrangements, 2 classes of construction. Request Bulletin 605-A, 605-C. UTILITY SETS--Self contained units for a wide variety of ventilating applications. Manufactured in 14 sizes with for ward curved rotors, 12 sizes with backwardly inclined blade rotors, single width only. Request Bulletins 610-A, 611-B. EX FANS -- Radial blade fan used chiefly for conveying ma terials, fume exhaust, etc. Manufactured in 15 sizes, single width only, all arrangements, 5 classes of construction, 3 wheel types. Request Bulletin 461. FC JUNIOR FANS--Self contained direct connected fans,with"' forward curved rotors. Manufactured in 5 sizes with 13 motor speeds, single width only. Request Bulletin 422. RB FANS -- Radial blade fan well suited for handling grease or other sticky materials. Manufactured in 13 sizes, single width only, all arrangements, 2 classes of construction. Re quest Bulletin 450-C. HP FANS -- Designed for applications requiring low air vol umes at high pressures. Manufactured in a variety of combi nation sizes. Request Bulletin 470. TYPE "M" FAN UNITS--Self contained units for a wide variety of commercial and industrial requirements. Manufactured in 7 standard sizes, units are available with accessory face and by-pass dampers, filter boxes and mixing boxes. Request Bulletin 510-A. TYPE "V" ROOF VENTILATORS --Backwardly inclined blade centrifugal type. Manufactured in 13 belt driven and 12 di rect driven sizes with steel, aluminum, copper or stainless' steel housings. Request Bulletin 410-B. - TYPE "S" ROOF VENTILATORS --Backward inclined blade cen trifugal type. All units fabricated from spun aluminum. Available in both direct connected and belt driven models. Request Bulletin 411.  200 Air System Equipment * Fbi BAYLEY BLOWER COMPANY Engineered Air-Handling Equipment 1821 S. Sixty-Sixth St. Milwaukee 14, Wis. Representatives In Principal Gties GENERAL VENTILATING & AIK-CONDITIONING FANS Bayley Type AP Fans have backward-inclined blades, non-overloading power characteristic. They are made in Classes I, II, III & IV for air-conditioning systems, plant and building ventilation, process air-bandling, mechanical draft. Sizes from 12R-in. to 132^-in. wheel diameter, capacities from 1000 to TOO,000 cfm, all standard drive arrangements, single and double width. Complete line of modifications and accessories. Sizes up to 365 (36H-iQ- wheel diameter) have reversible housings, facili tating prompt delivery of any discharge position in popular drive arrangements. All standard housings are made with scroll seams inside-welded for strong, tight con struction, smooth exterior. . BELTED VENTILATING SETS Compact unitary sets, complete with drive and motor, serve a wide variety of applica tions, such as kitchens, gymnasiums, lavatories, garages, restuarants, hospitals, laboratories, industrial plant areas. Sets may be used for supply or exhaust ventila tion. They are available in wheel diameters from 9-in. to 36H-in., fr capacities from 500 to 15,000 cfm. Smaller sizes have Type F forward-curved wheels, larger sizes have Type AP backward-inclined wheels, as required for most suitable drive selections. Wheels and housing are of same design and construction as regular Gass I fans. Pro tective drive covers and automatic outlet louvres are available for outdoor installa tion. ' DIRECT-DRIVEN VENTILATING SETS Sets with forward-curve wheel mounted on motor shaft are particularly suited for light-duty low-capacity requirements. Wheel sizes from to 10H-in., capacities from 100 to 1500 cfm. Larger sizes, made to order as regular arrangement 4 fans. Typical applications include small rooms, booths, cabinets, compartments, equip ment cooling. Housings and wheels are designed and built for permanency under hard usage. Inlet screens and filters are available. Also can be equipped with motor cover for outdoor installation. These sets are particularly recommended for in corporation as ventilating or cooling fans in factory-built apparatus. INDUSTRIAL EXHAUST FANS Type EX Fans are of the radial-blade medium speed design best suited to the wide diversity of industrial air-handling requirements. Sizes range from 5-in. to 60-in. inlet diameter, &-%-in. to 104j-in. wheel diameter. 200 to 55,000 cfm capacity. Style GP. open, back-plate wheels are recommended for the majority of materials handling applications. Style AH closed wheels are designed for maximum efficiency when handling clean air or gas. Many modifications and special construction features fn be incorporated for unusually severe conditions of abrasion or corrosion. Tem peratures up to 1450 F can be handled with appropriate bearing selections and heat flinger arrangements. PRESSURE FANS Type H Fans are proportioned to suit high pressure/volume ratio characteristically required in certain phases of pueumatic conveying, cupola blast, burner draft, suction or blast cleaning, and the like. Usual pressure range is from 12-in. WG to 55-in. WG (2 psi). Four designs are offered: No. 1, to 21-in. SP; No. 2, over 21-in. to 28-in. SP; No. 3, over 28-in. SP to 35-io. SP; No. 4, over 35-in. SP. While basic sizes and propor tions are established, the necessary flexibility of selection for the wide range of pres sure volume combinations is provided by varying widths of fans as required. Wheel diameters are also variable in sufficient degree to achieve proper operation at stand ard direct-connected motor speeds. Air System Equipment r. 201 sp BROOKSIDE ORPORATION _ McCardsville, Indiana Manufacturers of: Fans Blowers Ventilating Equipment Brookside Corporation is large, enough to serve you well--small enough for frequent contact between management and production supervisory personnel to insure top. quality sod coordination of all customer requirements. Brookside offers custom en gineering free of charge--and production at competitive prices. A company-owned airplane is maintained to offer the fastest possible service and engineering assistance when it is necessary. M-PEL-AIR 6-BLADE ONE-PIECE FANS; One piece fans in a wide range of sizes from 6 in. diameter 4-Blade to 14 in. diameter 6-Blade. Some models with slinger rings for room air conditioner application. Manufactured of aluminum or steel. 4-Blade with Ring M-PEL-AIR AUTOMOTIVE TYPE: Heavy-duty automotive type fans, both single and double spider types, in both steel and aluminum blades. A wide range of sizes from 10 in. diameter through 85 in. diameter. Available in 4, 5, 6, and 8 blade designs. Suitable for use on gasoline or diesel engines and cooling tower applications. 4-Blade without ring 6-Blade without Ring . M-PEL-AIR ROOF EXHAUSTERS: Available in a wide range of models and types ranging from 250 cfm to more than 11,000 cfm Spun aluminum construction with aerodynamic design for greater efficiency. Entire line features extremely low sil houette. Backward inclined, non-overloading centrifugal fan wheels assure quiet oper ation. .' M-PEL-AIR GRAVITY ROOF EXHAUSTERS: Engineered and designed for fresh air intake or relief of pressure within building. Lightweight, spun aluminum housing construction. 8 Models. Motor operated or spring loaded back-draft eliminators, cylindrical bird guards, bug screens optional on all models. Offset Type M-PEL-AIR BELT DRIVE ROOF F.XHAUSTERS: Power visit 13 resilient-mounted for quiet operation. Fan wheel design, unrestricted air flow make for quiet operation. Rigid spun aluminum housing. All belts, pulleys, bearings and motors standard sizes. Low silhouette blends well with' contemporary architecture. * Direct Drive Exhauster 4-5-64 8-Blade Autoraoti re Type M-PEL-AIR FAN BLADES: Slinger-type for air conditioning or offset spider and conventional propeller type fans for ventilating and other applications. All engineered exactly to your specifications free of charge. Slinger rings are all one-piece die drawn. Research and laboratory facilities available to solve air moving problems on your product. . - M-PEL-AIR SIX BLADE: One-piece or fabricated construction in a wide range of diameters, any pitch, in aluminum or steel. Gives efficient air movement against higher static pressures. Solid or resilent hub. Also available in three and four blade. Gravity Roof Exhausters 6-Blade One Piece M-PEL-AIR OFFSET TYPE: Gives maximum space-saving features by bringing blade around the motor. Brookside's advanced design blades give higher efficiency and may be made reversible. M-PEL-AIR SLINGER BLADE: Solid die-drawn slinger non, with the tabs a part of the blade, operate at low sound level and high efficiency. Designed especially for air conditioning and refrigeration industry. . Belt-Drive Exhausters 100 Series M-PEL-AIR 100 A 200 SERIES BLOWERS: 100 series specifically designed for higher pressure applications. Rugged construction with conical shaped inlet ring welded to blades. Available from 14 to 60 inch diameter. Series 200 designed for lower pressures. Fabricated of aluminum, stainless, or steel, riveted throughout. Both series have backward inclined blades for low noise and non-overloading characteristics and are statically and dynamically balanced. #202 Air System Equipment p*= m4 nuw*m BUFFALO FORGE COMPANY 450 Broadway, Buffalo, N, Y. Canadian Blower & Forge Co., Ltd., Kitchener, Ont. Ventilating Fans (centrifugal, axial Sow and propeller), Mechanical Draft Fans, Blowers, Exhausters, Air Washers, Drying Equipment, Air Conditioning and/or Cleaning Equip ment, Unit Heaters, Air Preheaters, Packaged Power Roof Ventilators, Makeup Air Units, Spray Nozzles. "Buffalo" is ready to work with you on any air problem you may have. Call the "Buffalo" Engineering Representative in your nearest principal city, or write for Bulletins mentioned below. TYPES "BL" AND "BLH" VENTILATING FANS. Quiet, efficient, non-overload ing fans with completely stable performance from free delivery to shut-off. Type "BL" Fans are designedforClasses I-II operation (moderate pressures). Type "BLH" Fans are designed for high pressure service covered by Classes III-IV. To provide minimum turbulence both fans have smoothly-curved inlet bell with directional guide vanes, wheel with full curvature shroud matching the inlet bell and stream lined, wheel-contoured housing. Type "BLH" Fans have divergent outlets, further minimising turbulence. Capacities: 1,000 to 500,000 cfm. Write for Bulletins F-104 and F-200. INDUSTRIAL EXHAUSTERS. All- welded steel plate construction is used in these heavy-duty fans. This provides smooth, rivet-free interior surfaces for minimum friction. Ease of maintenance Type is afforded by removable front and back plates. Available with interchangeable Air Wheeb for airborne dusts, gases, fumes, or with Material Wheels for grit, sawdust grain, stringy materials. Corrosion-resistant construction can be specified. Available with neat stingers to handle gases up to 1000F in induced draft and other high tem perature applications. 600 to 37,000 cfm capacities. Write for BULLETIN FI-110. AXIAL FLOW VENTILATING FANS. These lightweight fans-fit into straight duct runs, requiring no more room than a section of round duct for ventilation, Industrial Exhauster exhausting, system boosting, draft and circulation applications. Extremely ef- ... ficient, quiet and non-overloading. In Vaneaxial fans, guide vanes redirect swirling air at fan outlet, converting it into increased forward thrust. Also available in Tube axial modeb (without directional vanes). Drives include direct connected motor-in- bousing, or V-belt drive with motor out of air stream. Models for high or low tem peratures, non-sparking and/or corrosion-resistant construction. Capacities: 2,000 to 65,000 cfm. Write for BULLETIN 3720-A. Axial Flow Fan AIR CLEANING EQUIPMENT. Air Washers for cleaning, humidity control, heating and cooling are only one of the many types of units built by "Buffalo." Also available are highly specialised units for abating nuisance effluents in the chemical and process industries. More than a half-century of experience in this field is at your service, plus our complete manufacturing facilities. Write for Bulletins on industry-proved "Buffalo" equipment to solve any air cleaning or processing problem you may have. UNIT HEATERS. Widely-used for versatile, economical, efficient "spot-heating". One-piece, seamless copper coil is continuous from inlet to outlet* discharge ground joint. This makes "Buffalo" Breeso-Fin Heaters desirable for high pres sure steam systems because it eliminates all possibility of leakage inside the unit. Safety is insured for steam pressures up to 250 lbs. These units also operate on as little as 2-lbs steam. Adjustable louvers aim heat where needed; fins are spaced for maximum radiation; high-efficiency fans give quiet operation. Write for BULLETIN 3137E. Also, a wide selection of heating and ventilating units, with or without filtered intake and by-pass dampers, suspended and floor models for large Control Cabinet ZONE CONTROL CABINETS. These quiet, compact, efficient units are designed for installations where it is most feasible to use a single unit to provide varying degrees of conditioned air for several zones. Temperature is controlled by mixing cooled and heated air in correct proportions to suit each conditioned space. No need for separate reheat coils and their controls; Sectionalized for easy handling ana installation. Convenient to service, with handy access doors, removable panels and outside-located bearings. Space-saving design with floor or ceiling clips. Can be adapted to any combination of heating, cooling and/or dehumidifying. Writ for BULLETIN AC-220. * Air System Equipment an #203 CENTURY FAN & VENTILATOR COMPANY, Inc. 45 Cedar St., Stamford, Conn. Plant # 2 Torrington--Burrville, Conn. Member of Air Moving Conditioning Association Orer 25 years experience and engineering development behind its time-proven performance CENTURY CYCLONE ROOF FAN A heavy duty centrifugal roof fan--compact, symmetrical and weatherproof design. High efficiency, large volume capacity, slow operating speed and quiet performance maxes the cyclone roof fan excellent for schools and institutional type buildings. Housings supplied in galvanised steel, aluminum, copper or stainless steel. Basic frame work constructed of heavy steel that guarantees long life and vibrationless operation. ' '* Motors belt or direct driven in separate compartment--out of air stream. Fan wheels are statically, dynamically ana electronically balanced. Heavy plate construction, backwardly curved non-overloading type also furnished in non-spark ing aluminum construction. * Motor and fan assembly suspended on rubber vibration eliminators. CENTURY SPUNAIR ROOF FAN Designed to meet the modem architectural detail of low, one story buildings--streamlined gleaming appearance, low con tour and simplicity of design. - Housing is ofheavy gage spun aluminum--completely weather proof. Designed to permit straight flow exhaust with venturi inlet to minimize turbulence. - The fan wheel is of heavy gage nigged construction--back wardly inclined, non-overloading type, statically and dynami cally balanced, and quiet in operation. -Motor and fan are resiliently mounted out of air stream in ventilated compartment. ' Spunair fans are made in direct and belt drive. Also furnished less motor and fan for intake hood. Self-acting or electric operated damper. TYPE MVF ROOF FAN Meets the requirements of extra large exhaust volume, incorporating low contour design and rugged construction. -Housing-made of galvanized steel,- aluminum, copper or stainless steel. Heavy duty propeller--four blade--for low static pressure up to in., and eight blades for static pressure up to % in. W.G. .. . Direct and belt drive--hinged hood for accessibility. Supplied with self-acting or motor operated damper. CENTURY BLOWER Utility Blowers FC and BC--forward curved and backward curved non-overloading type wheels made in sizes 6 in. to 36 in. wheel diameter. Sizes 12 iD. to 96 in. wheel diameter Class 1 Blowers........................................................................ up to in. S.P. Class 2 Blowers....................................:------ *........................3? in. to 6H in. S.P. Class 3 Blowers......................................... .............................in. to in. S.P. Heavy construction, manufactured in accordance with AMCA code of standardised arrangement, and testing procedure. -_ Newly designed high efficiency blower wheels are statically and dynamically balanced on the latest electronic balancing equipment. CENTURY DRAFT INDUCERS Induced Draft Fans provide the proper draft without the use of high chimneys. TYPE MID Inducer is an axial flow, non-overloading type fan, which is easily in stalled on the boiler breaching. . Bearings and shaft are protected from heat by a double shell shaft tube with impeller blade to keep a steady flow of cool air over the shaft and bearings. Adjustable barometric damper with self contained explosion relief valve. Motor is standard single or two speed belt driven, and protected with ventilated aluminum heat shield. . . THE AUTOMIC. INDUCER is a backward curved, non-overloadiag centrifugal type blower for heavy duty service, and used when high static pressure is encoun tered, such as old flues of undetermined resistance.' Motor may be single or two speed, and with adjustable sheaves. When used with sequence controls, the draft will be constant regardless of conditions encountered. #204 Air System Equipment CHAMPION BLOWER & FORGE CO. LANCASTER, PA. Address Correspondence to Out. 9 Manufacturers of Blowers, Ventilating Fans and Exhaust Fans for handling air, material and fumes Representatives in Principal Cities Champion Type D vent sets for general ventilation of all types equipped with backward curved non-overloading wheels up to 30 in. diameter, furnished complete with electric motor, adjustable drive and weather proof covers if required. Champion Forward and Backward Curve Ventilating Fans and Exhaust Blowers manufactured in sizes up to qq ^ diameter. Fans also furnished in all standard arrangements with Ball, Babitted or Water Cooled Bearings as required. ' Air System Equipment AIRFOIL BLADED CENTRIFUGAL FANS. for heating, ventilating, air conditioning systems Aerodynamically-ehaped blades move more air with less turbulence, thereby achieving higher efficiencies with reduc tions in noise and current consumption, efficiencies up to 92 percent ' - noise redaction up to 40 percent horsepower savings up to 20 percent Capacities: 440 to 561,680 cfm up to 32 in. SP. Sixes: 1214 to 80%- Class I to V arrangements for heavy and standard, service. Direct or belt drive. Single or double inlets and widths. Adjustable and fixed housings for all discharge positions. Specified since 1951 for: high pressure and couventional ven tilation. air supply and exhaust. - industrial processing. mechanical draft.. 205 CHICAGO BLOWER CORP. 9871 Pacific Avenue, Franklin Park, Illinois Blowers, Fans and Exhausters for Every Air Movement Requirement AIRFOIL MECHANICAL DRAFT for power stations, heavy'indtutry All performance advantages of Airfoil Fan. Capacities: up to 1.097,940 cfm for temperatures to 900F; Ya to 32'in. SP. Sixes: 24Yt to 80%. Single or double width, with or without inlet boxes. Welded heavy steel construction. AXIAL AIRFOIL FANS for exhausting fames, hot gases; ventilation Welded airfoil type blades provide higher pressure characteristics, les noise and greater strength. Capacities: 1100 to. 105,000 cfm up to 5 in. SP. Sizes: 12 to 72. Orifice ring, duct, cradle, pedestal. STEEL PLATE EXHAUSTERS for material and dost handling Separate wheels handle wood shavings, grinding dust, paper, fibrous and heavy materials. Capacities: 200 to 50,000 cfm up to 15 in. SP. for temperatures to 1200* F. Sizes: 15 to 100. Arrangements for belt and direct drive. Adjustable. Champion Cast Iron Housed Fans of various types for fume hood exhaust and for handling corrosive gases. Can be equipped with either plain steel or non-ferrous blast wheels, interior of housing and wheel can be covered with special corrosive resisting coating. Champion Ventilating Fan for moving large volumes of air in either direction by reversing the rotation of the fan wheel. Develops pressures over \Vi in. w.g. Built in sizes from 18 in. to 84 in. diameter. Equipped with double Ball Bearings. MD FANS for ventilating industrial, commercial, publie buildings "Large volume and low pressure types housed in cast iron or heavy steel. Welded backward or forward curved wheels. Capacities: 300 to 17000 cfm up to 1% in. SP. Sizes: 62 to 300. Belt or direct drive, adjustable discharge. TURBO PRESSURE BLOWERS for combustion, air, forging, pneumatic systems Supplies steady, high speed air pressure or suction. Capacities: 125 to 5250 cfm at pressures from 4 to 28 os up to 750" F. Universal discharge adjustments. Direct or belt drive. POWER ROOF VENTILATORS for industrial, commercial ventilation Packaged high velocity type. Welded axial airfoil wheel. Automatic butterfly damper--has emergency opener. Capaci ties: 6040 to 53,700 cfm up to % in. SP. Sizes: 24 to 60. Steel, aluminum or stainless housings--flat or pitched bases. Weatherproof motor. Others on request. Technical Data Bulletins Available Upon Request  206 Air System Equipment * f= '--a CLARAGE FAN COMPANY Kalamazoo, Michigan Air Handling and Conditioning Equipment Sales Engineering Offices in All Principal Cities Since 1913 Clarage has been a leading manufacturer of air handling and conditioning equipment. By specialising--building a complete line of this equipment exclusively--Clarage has a concentrated "know how" that means important dividends to the user. (See "Air Conditioning Central Systems" for other Clarage products.) Clarage Fans for ventilating, air conditioning, and in dustrial applications--where clean air is handled at low pressures--are offered in many different designs, ar rangements, and wheel types. Capacities range from 140 to 725,000 cfm. Clarage Fans for industrial air handling and material conveying are available in a wide range of types and sizes. This broad line includes cast iron fans, fans for pressures to 50 in. sp, and fans for temperatures to 1000 F. Clarage Ready Unit Ventilating Sets for smaller venti lating supply and exhaust jobs. Furnished complete, ready-to-run for both direct drive and V-belt drive. Capacities 150 to 14,000 cfm. Clarage Centrilator Power Roof Ventilators (shown without cover) are V-belt driven. Capacities 1,500 to 26,500 cfm. Directilators are direct drive unite. Capaci ties 100 to 3,500 cfm. . Clarage Mechanical Draft Fans. Forced draft and in duced draft fans are available to meet virtually any capacity, pressure, and speed requirement. Unit shown has sections of housing and inlet boxes removed. Clarage Unit Heaters. Unitherms (shown) are equipped with centrifugal multiblade fans. Clarcos, for smaller space, heating assignments, have propeller fans. Air System Equipment ad BUwan 207 DeBOTHEZAT FANS DIVISION American Machine and Metals, Inc. Main Office and Factory--East Moline, Illinois Sales Engineering Offices In All Principal Cities Consult Your Telephone Directory Under "Fans** or "Ventilating Equipment" FOR CONTROLLED VENTILATION Centrifugal Roof Ventilator--low-contoured, distinctively profiled--operates at very low noise levels. It is highly efficient against static pressures. Its large unit ex haust capacity is accomplished at low fan tip speeds by a backw&rdly curved non overloading fan wheel. Capacities up to 32,980 cfm. Write for Bulletin. Centrifugal Roof Ventilator Vertical Discharge Roof Ventilators are designed for found ries, machine shops and other buildings where much oil or dust is in suspension in the air. This unit is economical in first cost and is convenient to install and maintain Exhaust airetream disperses dust particles into atmosphere. Capacities up to 48,925 cfm. Write for Bulletin. - Vertical Discharge Roof Ventilator Power-Flow Roof Ventilator Power-Flow Roof Ventilators provide controlled ventilation at all times, regardless of; jveather. This unit is a motor-driven fan in weather-proof housing, designed to provide positive controlled ventilation. Works efficiently with or without a duct system. Capacities up to 43,070 cfm. All three DeBotbezat roof ventilators are low in silhouette and distinctly profiled... blend well with modem architecture. Write for Bulletin. FOR FUME REMOVAL Bifureator Fans are excellent for exhausting air that is abnormally hot, corrosive, flammable or explosive. Motor is mounted in separate chamber and destructive fumes are by-passed (bifurcated) around it. Installs as a part of the duct horizontally or vertically. Fan wheels .12 in. through 48 in. in diameter, with capacities up to 54,200 cfm. Write for Bulletin. Induced Draft Bifurcators provide controlled draft for boilers and furnaces, minimizing the need for large costly stacks. Built with fan wheels 12 in. through 36 in. diameter for-high pressure boilers delivering up to 60,000 pounds of steam per hour--low pressure boilers delivering up to 190,000 EDR. Write for Bulletin. "Hy-V" Air Jet is used for air quenching and solving pro duction cooling problems. Effective for reducing fatigue' of workmen exposed to radiant heat from ovens, furnaces, forges or molten metal. Two styles--for stationary mounting or mounted on 2-wheel stand for easy mobility. Available with fan wheels 18 in. through 30 in. in diameter. Write for Bulletin. Additional bulletins are also offered on Axial-Flow Vent Sets and Panel Vent Seta. Induced Draft Bifurcator Bifurcator Fan BONDED RATINGS Published DeBothezat ratings are hacked by a $750,000 Performance Bond on deposit with New York Trust Co. Ratings are the output of the completely assembled unit, obtained under wind tunnel tests as per Standard Test Code for the particular product classification and conform to U. S. Department of Commerce Standard 178-51. "Hy-V" Air Jet  208 Air System Equipment Fm ni Ww*n Garden City Fan Company 801 North 8th Street Niles, Michigan Representatives in principal industrial cities Manufacturers of Design MB" Multiblade--Non-Overloading--Hi-Static and HSH Cycloidal--Radial Blade Indus trial and C. I. Small Exhaust Fans. Wheels designed in forward curved, backward curved, and radial blade types for various commercial and industrial applications. Suitable for high temperature air circulation to 1850 F, air condi tioning and ventilating, dust and fume removal, heavy materials conveying, and special applications requiring` Cus tom-built" features. High temperature fans-are equipped with a special "air-cooled" shaft which eliminates bearing failures caused by excessive temperatures. v Design "B" Mnltiblade Fans--Compact, low speed air and gas handling fans with forward curved blades. Made for temperatures to 1650 F in uninsulated and insulated double housing construction. Well suited for systems with space limitations or low. noise level re quirements. . Non-Overloading Fans--High speed air and gas han dling fans with backward curved blades. Non-overload ing power characteristics. Made for temperatures to 725 F. Well suited for systems with fluctuating system resistance. Design "By Multiblade Fans Radial Blade Industrial Fans--Heavy duty air, gas, and material handling fans. Made for temperatures to 1850 F in uninsulated and insulated double housing construction. Used for many material conveying ap plications, for all high temperature applications,, and for exhausting against high pressures. C. L Small Exhaust Fans--Durable air, gas, and material handling fans with heavy cast housing. Made for temperatures to 1650 F. Particularly suitable for applications requiring small volumes at moderate static pressures. Further information and literature available upon request. Hi-Static and HSH Cycloidal Fans--Rugged material handling and conveying fans. Two classes of construetion designed to handle a wide range of materials. Specially designed "non-clogging" Cycloidal wheel re duces power requirements while offering efficient performance at low speeds. Non-Overloading Fans - f . Hi-Static and HSH Cycloidal Fans C. I. Small Exhaust Fans Radial Blade Industrial Fans Air System Equipment General Blower Company 8602 Ferris Ave. MORTON GROVE, ILLINOIS Sales Offices in Principal Cities 209 General Backward Blade Centrifugal Fans for beating, ventilating- and air conditioning are non-overloading, quiet and efficient. Selection ranges through nineteen fan wheel diameters from 12V$ inch to 73 inch. Bulletin BB-105 bears the AMCA seal of certification. General Forward Curved Centrifugal Fans are offered in a complete range of sices for low speed, quiet operation. Bul letin FC-101R bears the AMCA seal of . certification. ' General Backward Blade wheel and In let cone are assembled of spun parts for smooth, quiet air movement. Wheels can be manufactured of alley materials alu minum or hot-dipped galvanized. Arfr for Bulletin BB-105. General Forward Carved fan wheel and inlet cone are assembled of spun parts for smooth quiet air movement. Wheel and cone can be manufactured of alley materials, aluminum or hot-dipped gal vanised. Ask for Bulletin FC-101R. General Util-A-Vents with BB wheels are recommended for low cost air han dling requirements. Belted and direct drives from 12 inch to 36 inch wheel di ameters. Bulletin UVS-104' bears the AMCA seal of certification. "DURA-TEMP" Heat Fans--Forward Curved and Radial BLaded Fans from 350*F to 1650*F. Heat resistant alloy and 5-ia. insulated construction. Backward Blade Non-overloading Heat Fans to 850*F. Bulletins HF-100 and RF-100A. General Industrial Fans for conveying dust and air borne materials. Four types of fan wheels available for air, fumes and materials handling. Modified construction for high temperature and corrosive con ditions. Bulletin IF-100. Turbo Blowers in two basic types: Type S single stage, and type M multi-stage. Both types used for gas and oU burners or gas boosters. 4 os pressure--90 cfm, to ` 48 oz pressure--6000 cfm. Bulletin TR IM. General Util-A-Veat Jr. with FC wheels are recommended for low cost air han dling requirements. Belted and direct drives from 5 inch to 12 inch wheel diam eters. Bulletin FP-101. ALL GENERAL FANS TESTED ACCORDING TO AMCA STANDARD TEST CODE  210 Air System Equipment pM JOY MANUFACTURING CO. General Offices: Henry W. Oliver Building, Pittsburg 22, Pa. BUrs Joy Axivane FANS SERIES 1000 Cot out drawing shows compact construction and motor location Joy AXIYANE Fans, Series 1000, are available in 136 sizes to a volume capacrfy'of 200,000 cmf and pressures up to 11 inches. Diameters range from 18 inches to 84 inches. Outstanding characteristics of Joy AXTVANJS design are: straight air flow, blades adjustable on the job for volume or pressure change and simplified installation. COMPACT * Joy AXIVANE Fans are built around the motor which permits the fan housing to become an integral part of the duct system. This inline installa tion frequently produces up to 70 percent more useable space than is available with conventional belt-driven centrifugal fans. Fan rooms can be eliminated in many instances. Front view shows simplicity of construction EFFICIENT Joy AXIVANE Fans utilize an aerodynamically efficient moving blade and stationary vane design that partially recovers the energy output of the rotor. Air is rotated by the blades, straightened by the vanes and passes through the duct in an axial flow with little pressure loss or turbulence. The natural result is increased efficiency. . EASY TO INSTALL Because Joy AXIVANE Series 1000 Fans develop greater pressures and volumes per pound of unit, lighter units than equal centrifugal fans can be used. In addition, the induct installation eliminates complex duct off sets and elbows, drives, guards and foundations. ' Joy AXIVANE Fans are shipped ready to install, and, in most cases, can be placed in service quickly and easily by relatively inexperienced or un skilled labor. Rear view show's vanes and motor ADJUSTABLE BLADES Joy AXIVANE Industrial Fans have the extra performance flexibility of adjustable blades. Adjustable blades are standard equipment on all Series 1000 fans. The factory blade setting can be quickly changed to provide either a wide pressure range for any particular volume or a change in a volume simply by loosening a lock nut with a wrench, setting the blades uniformly with the indicator, and retightening the lock nut. A permanent stop prevents setting blades in a position likely to overload the motor. Minimum blade settings are limited by the fan housing. Blades are adjustable on the job by loosening each lock nut. Settings are permanently stamped on hub. This feature permits change of air pressure or volume. Added advantage of the Joy AXIVANE design is that fan noise usually occurs at frequencies which are responsive to acoustical correction. Joy Manufaclurittg Co. 211 MATCHED ACCESSORIES Inlet bells, screens, and fan supports are accessories designed to fit all AXIVANE fan housings. In order ing, it is only necessary to state the fan model number, with or without the accessories, as desired. If required with accessories, these will be furnished to fit the fan model ordered. NOTE: An incorrect inlet bell will reduce fan effi ciency by increasing intake turbulence which, in turn, increases noise level. When a fan takes its air directly from the weather, plenum, fan room, or duct system larger in circumference than the fan housing, a bell should be used. The Joy Microdyne Dust Collector is a compact, wet inertial unit, Ho to Ho the size of any other collector. It collects over 99 percent of all dust particles 5 mi crons and larger, 92 percent of 2-micron dust, and sub stantial amounts of smaller dust. Cylindrically-shaped, it installs directly into the duct system--often at the point of use. It is available in ratings from 2500-to 64,000 cfm, constructed of mild steel, or Type 304 or 316 stainless steel for various corrosive and erosive conditions. i Dart frUde Sat Memmi ta Ittram LITERATURE AVAILABLE Industrial Fans--Bulletin J-611 Aircraft--Electronic Fans--Bulletin J-614 Joy Microdyne Dust Collector--Bulletin J-616 Write to Joy Manufacturing Company, Oliver Building, Pittsburgh 22, Pa. or offices listed below and specify Bulletin Number: DOMESTIC AND EXPORT OFFICES UNITED STATES AND TERRITORIES ALA., BIRMINGHAM.......... Ml--1-0th -St. -N-. (C- randall Eng.) Calzt., Los Anqeles 3. ................... 5426 E. Washington Bird. Gaut., San .Francisco t-. Com., Denter I............... D. C., Washington 6........ III., Crxtralia................... .............. ......................115S HA/riasa St 106 Waxes St (Sehloss A Shubart) ............................... 1T11 K. St, N.W. ............................. Filth and Chestnut III., Chicago 8................... mm., Burlington.............. Mica., Detroit 25............... .................... 560 W. Washington Bird. ....................................... Second Are. ...................... 17615 W. McNichoIs Rd. Mon*., Duluth..................... Mont., Bom........................ ................................. 1021 E. Superior St ...................................24 W. Granite St Mo., St. Loots 10............... N. Y., New York 6.............. ............................ 1203 MacUind Are. .....................:....................140 Cedar St Onto, Cleveland U............. Ore., Portland o................. .................................. I6I41 Purrtai Are. ........................ 1831 N.W. Thurman St Pa., Luzzeke.......................... ........................................... 453 Main 8t Pa., Pittsburgh 16............... ................................ 3021 Banksrille Rd. Pa., Philadelphia 3............ Tens., Kmrnnn............... ..................................... 1420 Walnut 8t. ...................................KB W. Main St Tex., Dallas........................ .................................. 7425 Hines Bird. Tee., El Paso.................... .................................. 1022 Wyoming St Utah, Salt Laer Cm 4... .....................OSS South Sixth West St Wash., Seattle 1................. .................................. 2411 Western Are. W. Va,, Hbwtznctcn............ 742 Eighth Are. Alberta, Calgaet............. . ,737-2nd Are., S.W. / Be. Colombia, Vakcqoteb. ........ 8883 Hudson StX Nova Scotia. Sidmbt........ .......87 Charlotte St Ontario, Galt..... ......... ...... .......... 173 Bererir 8t Ontario, Kirkland Lake.. .........24 Duncan Are. Ontario, Sudrurt............... .......... 371 Spruce St Ontario, Toronto,.............. Quebec, Montreal.............. ...........384 Montee Do lieaae, VUle St Laurent IN MEXICO Mexico, Mexico Cm............................................................ Insurgoxtes 8ur 123 EXPORT OFFICES N. Y., Hew Yore........ . ....... 80 E. 56tb St Algesia, Algxebs...................... .Cnranagnie Joy, S.A.4, Roe Charles Vaiiia Australia, Bosebsskt.............. ..................................... 55-58 Rothschild Are. Belgium, Brussels................... ............................... 88 Bird, do llmperatriee. Brasil, Rio or Janeiro............ .......................... Caixa Postal, 54, Copacabana Chile, Santiago........................ ................................................ ........ CaaUa 88-D England, London WI............... .........................................................7 Harley St France, Paris............................ ........................ .................. 30 Hue de Gbidtfo! Morocco, Casablanca.............. Ci*. (Marocaine) Joy, S. A. Rue da Verdi Northern Rhodesia, NTIola. --.........Joy-SuQiran (Africa) (Pty.) Ltd. Peru, Lima.................................. .......................................................... Canlla 3111 Scotland, Renfrewshire......... ....... Joy SuUirxa Ltd.. Cappidow. Greooek Sooth Axeica, Johannesburg. 1 Steele St, Stcdedsie AND MORE THAN 500 DISTRIBUTORS THROUGHOUT THE WORLD  212 Air System Equipment * 5" THE LAU BLOWER COMPANY 2027 Home Avenue, Dept. J, Dayton 7, Ohio Other plants in Kitchener, Ontario, Canada and Irwindale, California LAU all new *ELECTRO-WHEEL BLOWER: Two unobstructed air inlets on wheel sides plus compact motor design gives more air delivery with less power load. Stationary shaft with rubber mountings reduces vibration to a minimum. Rugged tripod mountings give extreme shipping strength without impeding air - flow. Air deliveries from 500 to 1500 cfm, static pressure from 0.5 to 1.25 in. (water gage), )4 and M hp motor, 9 in. and 10 in. wheels. Available in 115 and 230 volt a-c. Housing supports optional. Pre punched `.holes in housing unit make any discharge angle possible. LAU Econo-Pak Blowers cover most applications for residential air-moving equipment; effect savings up to 10 percent by eliminating special blowers for each ' application; reduce blower inventories by simplified order procedures, quick handling of model changes, lower handling costs, up to 26)4 percent reduction in warehouse space. Four Basic Sizes each in 2 widths, with all features of Standard Series A Blowers. Package Includes blower wheel, housing with cut-off, housing supports, motor mount (not attached), all hardware; wheel, housing, bearings and shaft assembled. Ex clusive Lau-Pak Bearings without oil cups re quire no lubrication. Adjustable Discharge, any one of 5 positions. LAU Standard Blower Assemblies (Series A), heavy-gage steel housing assemblies, entire unit die-fonned. Capacity range 350-22,000 cfm. Motor Mounting adjustable for any motor location. Housing Base heavy gage steel, rigid. Discharge Outlet unproved design, construction. Custombuilt Belt special composition for blower operation. Shafting 2-stage centerless ground, burnished. Bearing Bracket 3-point suspension; same bracket used for all discharge'angles. Lausteel Pulleys employed; V.S. motor pulley allows speed variations up to 30 percent. Center Suspended Wheel. Embossing of Scroll Sides reinforces venturi inlet and discharge. Bearings highest, grade self-aligning porous bronze sleeve type. Plastic Thrust Washer absorbs shocks. LAU Preslok* Wheels, Center Suspended Riveted Wheels, S.l. and D.l. Weld Wheels, a complete wheel line. Preslok Wheels, sizes 9 in. through 1$ in. center disc construction; baked enamel, Ruspruf, or hot-dip galvanized' finish; standard steel or Power Lock hubs. Riveted Center Suspended Wheels, blades double-riveted to end rings, arc welded to center disc, diameters 22 in.-30 in.; standard steel or Power Lock hubs. S.l. and D.l. Weld Wheels, individual blades of correct length, width, pitch; baked enamel, Ruspruf, or plated; diameters 4^ in.-9 in.; widths 2)4 in.-9 in. T. M. Reg. U. S. Pat. Off. THE LAU BLOWER COMPANY 2027 Home Avenue, Dept. J, Dayton 7, Ohio Other plants in Kitchener, Ontario, Canada and Irwindale, California 213 Lausteel Variable and Constant Speed Pulleys are in balance and true-running. Lausteel- Variable Speed Pulleys available in three standard bores: and in. Diameter 3)4 in. OD. Allow speed variations up to 30 percent, for many drive combinations. Lausteel Constant Speed Pulleys available in diameters of 6, 7,8, 9 and 10 in., inclusive. Suitable for both "A" and "O" section belts. Lau also offers cast iron pulleys in diameters of 10 in. to 14 in. Write for LAU Blower Catalog LSO-463. LAU Large-Bore Wheels, made to traditional LAU rigid performance standards, are now available. Bores for 3 in., 4 in. and 4)4 in. shafting, with other bore diameters up to 5 in., are offered on Spun wheel sizes 9 in. through 18 in. and on Riveted wheel sizes 22 in. through 30 in. Variety of finishes (contact factory for details). NO set screws--no need for flats or keyways. New design eliminates excess weight of hub. Large-Bore Wheel LAU Self-Aligning Pillow Blocks are low-cost, light-weight, oil-tight steel housings with porous bronze bearings. Hold much more oil than cast iron types. Durex bushing feeds oil to shaft by capillary action. Spring keeps spherical surface of bearing and ring in close contact. Long bolt slots permit inter changing with other makes of pillow blocks. Bore sizes available are %, 1, and l-^6 in. ' Self-Aligning Pillow Block LAU Blower Catalog LSO-463 contains full information on Pillow Blocks and Pulleys.  214 Air Conditioning * FwpJlw rad C4ntrUncal' Pass ILG ELECTRIC VENTILATING COMPANY 2880 North Pulaski Road, Chicago 41, Illinois Offices ia 57 Principal Cities * Member of Air Moving and Conditioning Association, Inc. (AMCA) ILG PROPELLER FANS, CENTRIFUGAL FANS, ROOF VENTILATORS Tested and rated by AMCA, PPMA and ASHVE code. Capacity guaranteed TYPE "LQ" DIRECT-CONNECTED, SELF-COOLED MOTOR PROPELLER FANS--Dg's self-cooled motor features ventilated enclosure which keeps motor clean and cool. Permanently- lubricated bearings and direct drive eliminate periodic maintenance attention. Nonferrous Tvpe "Q," dynamically balanced fan wheel- Exceptionally quiet opera tion. Wide range of sizes. Send for Bulletin S-317. TYPE "XQ" Explosion-Proof Fan Motors carry UL certification of suitabil ity for all Class 1, Group D hazardous applications. Send for Bulletin S-317. TYPE "TAQ" Tubeaxial Duct Fans for pressures up to 1.5 in. Easily installed duct section for vertical or horizontal use. Nine sizes, 2 types. Type TAQ is equipped with 3-bladed propeller; Type TA features the new 5-blade design. Ca pacity, range at free air 1040 to 21,300 cfm. Send for Bulletin S-317. - VOLUME BLOWER TYPE "BM-- Small volume, low pressure, quiet run ning. Direct-connected motor. Universal discharge positions. 14 capacity models. Send for Bulletin 257-33. VOLUME BLOWER TYPE "P"--For exhausting dust, fumes, vapors. Cast iron housing and aluminum wheel. Di rect-connected motor. 9 capacity models. Send for Bulletin 15S-B6. NEW AIRFOIL TYPE BC DIRECTCONNECTED CENTRIFUGAL FANS Non-overloading type. Airfoil blade de sign with high efficiency. Suitable for AMCA Class 1, II and III operation up to 9-in. static pressure. Direct-drive de sign with motor partially recessed. 12 sizes. Single- and double-width models. Also belt-driven models. Send for Cata log 257. ILG L-LSQ (Exhaust) and L-SRQ (Sup ply) POWER ROOF VENTILATORS-- Direct-connected propeller fan type featuring low silhouette, high capacity. II sizes up to 21,100 cfm at free air and 13,800 at in. static pressure. Send for Bulletin 502. ILG PRV POWER ROOF VENTILATORS--Centrifugal fan type. Directdrive. self-cooled motor. Non-overioading, backward-curved wheel. 10 sizes. Send for Bulletin 1907. ILG L-CRF CENTRIFUGAL POWER ROOF VENTILATORS--Suitable for all duct systems. Large capacity and pressure range--from 155 cfm up. Low silhouette. Sizes 67 to 182 are all alumi num. Sizes 200 and larger complete hous ings are constructed oi spun steel. Back ward-curved airfoil fan blades of patented design for quiet, high-capacity per formance. Direct-connected, self-cooled - motor. Send for Bulletin 2701. Air System Equipment THE NEW YORK BLOW Elf COMPANY Sales Offices: 3171 South Shields Avenue, Chicago 16, Illinois MAKE-UP AIR UNIT UNIT HEATERS A unit that delivers warmed, filtered, out side air to industrial spaces to replace ex hausted air and bal ance minus pressure. Corrects drafty condi tions anduncontrolled infiltration. In 4 sizes from 5000 to 20,000 CFM. Bulletin 568. Ceiling suspension type with heavy duty, welded steel, ftn-and-tube heating element. Suitable for con tinuous heating service on steam pressures up to ISO pounds or more. 10 basic sizes, capacities from 31 to 300 Mbh. Bulletin 552. 215 M-15 UnH 154)00 CFM Unit HtaMr STANDARD DUTY IPL PAN A complete line of NAFM ar rangements in both forward and backward curved wheels. Class I, II, and II construction. Ca pacities from 1,000 to 175,000 CFM. Quiet operating with non overloading horsepower charac teristics for all heating, ventilat ing and air conditioning appli cations. Bulletins 561 and 572. IPL Fan PROPELLER FANS Propeller type ventilating fans deliver large volumes of air at low resistance and low current consumption. AU wheels are machine balanced for smooth, vibrationless operation. Made' in two types and ten basic sizes to cover a wide range of industrial applications. Square steel panels simplify installa tion. Wheel diameters from 10 inch to 48 inch. Direct or belted drive. Capacities from 610 to 24,200 CFM. Bulletin 564. Propeller Fan TYPE Gl INDUSTRIAL AND HEAT FANS Gl Heat Fan For dust and gas removal, conveying of materials and the handling of hot gases in industrial processes. Hous ings, drives, both pulley and direct, and dischargearrange ments to meet any require ment. With wheel diameters from 10 inch to 66 inch.Capacities ranging from 450 to 60,500 CFM. Bulletin 585. ROOF VENTILATORS These "Twins" are completely weatherproof and corrosionresistant, and of modem de sign. Bulletin 582. GENERAL PURPOSE FANS Portable, self-contained units for Class I indus trial and ventilating ap plications. Recommended for their ease of installa tion,lowmaintenance and space saving features. Made in four types and twelve basic sizes to meet a wide range of industrial application. Both direct connected and beltdriven. Capacities from 160 to 19,070 CFM. Bulletin 563. General Purpose Fan Bolt-Ex (above) exhaust* from hoods and dec* work; VP-Cx (right) for tower resistant*,. AIR MOVING and CONDITIONING ASSOCIATION  216 THE Air System Equipment Fu Burr* e*zu^&cttic COMPANY 1402 W. Market Street * Warren Ohio Representative* in Principal Cities ' Industrial and Commercial Ventilating Equipment Air System Equipment mmsmEj&vL division ROBBINS & MYERS, INC 1359 STONE BLVD. SPRINGFIELD, OHIO Industrial end Commercial Ventilating Equipment 217 BACKWARD CURVE CLASS I BLOWERS--In sites from 12-K in. to 36 in. ; self-limiting hp character istics; AMCA standards and' ratings; dynamically balanced wheel; heavy hub; nothing in air stream; quiet entry, job-matched motor; convertible discharge; belt drive or direct drive. UTILITY BLOWERS--Belt or direct drive forward curve wheels with clockwise or counterclockwise rota tion; through hp; motors in all current charac teristics; convertible discharge; arc-welded housing; sleeve or ball-bearing construction; weatherproof drive covers optional. - ' ARRANGEMENT 2 or 3, CLASS I or II--9 in. through 73-in. wheels; single width--angle inlet or double width--double inlet; forward curve or back ward curve type; all types of motors available; vibra tion bases, drives, inlet vane control and other optional features available; ball or sleeve bearing construction. RADIAL BLADE BLOWERS--^ to 5 hp; slow and high-speed' units; self-cleaning wheel; ball-bearing motors; discharge as specified; base and housing of heavy-gage steel. POWER ROOF VENTILATORS--CENTRIFUGAL OR PROPELLER TYPE--Direct or belt drive; 12 in. to 48 in.; 600 to 25,000 cfm; complete with discon nect switch; tingle phase or three phase motors; auto matic shutters; inside insulation; 16 gage housing; baked enamel finish. INDUSTRIAL EXHAUST FANS--Direct or belt drive; vertical or horizontal mounting; totally enclosed motors; adjustable motor base; continuous duty; ball bearing construction; cfm rating from 470 to 29,350; shutters, inlet guards and other optional features avail able. . .Type CD direct connected fans are designed for applications where the motor may operate within the airstream. They may be installed in any positioo in walls, roof ventilators, hoods or ducts. They are suitable for operation over a wide pressure range from free air to relatively high resist ance. Available in sizes from 7 Vt to 60 inches. Capacities range from 300 to 103,200 cfm. Request Bulletin 690. Designed for use in offices, schools, . stores or wherever quiet operation is needed. Special cast aluminum-magne sium alloy airfoil propeller eliminates the sounding board effect of thin sheet metal blades. Steel venturi entrance ring prevents air recirculation at pro peller tips, thus further reducing noise and increasing efficiency. Sizes: 12 to 36 inches. Capacities: 1235 to 12,000 cfm. Request Bulletin 695. Designed for large volume air deliv ery at relatively low noise levels and ' moderate pressures. For use in power plants, stores, auditoriums and fac- lories. Type CB fans may be wallmounted or used in the Sky-Blast power roof ventilator described be low. Heavy duty bearing assembly is equipped with extra-wide prelubri cated ball bearings. Sizes: 42 to 72 inches. Capacities: 14,200 to 58.100 cfm. Request Bulletin 740. TYPE SB SICY-BLAST Power Roof Ventilator Designed for general ventilation, high temperatures, high pressures, fumes, - gases and materials handling. Available with forward curved, backward in clined or radial blade wheels. All bear ings are isolated from the fag-housing. Available with clockwise and counter clockwise rotation in all standard posi tions. Sizes: 7Vi to 33 inch wheel diameters. Capacities: 270 to 19,070 cfm. Request Bulletins 750 anH 760. PROPELLERS Propellair fans are equipped with air foil propellers of a cast aluminum-mag nesium alloy that provides strength, dimensional stability and balance, and greater corrosion resistance. Airfoil design assures maximum efficiency and horsepower savings impossible to attain with overloading sheet metal blades. Two-blade designs are for use at, or near, free air. Multi-blade types are for use against resistance pressure.' A low-silhouette roof ventilator that blasts heat, moisture, dust and fumes high into the air away from roofs and windows. Free-swinging butterfly dampers open instantly at minimum air flow, close weathertigbt when' fan is off. All-steel construction, hot-dip galvanized after fabrication. Rain shed and condensate drain assure weatherproof service. Sizes: 16 to 60 inches. Capacities to 78,800 cfm. Request Bulletin 680. . For use in hoods, ovens, spray booths or wherever the motor must be kept out of the airstream. Designed for use at relatively high static pressures. Over size bearing assembly has sealed, pre lubricated ball bearings which may be relubricated. Corrosion resistant coat ings available. Nine shaft lengths from 16 to 66 inches. Sizes: 12 to 60 inches. Capacities: 1020 to 79,000' cfm. Request Bulletin 640. For handling damaging or dangerous exhaust requiring isolation of the motor from the airstream. Integrally rolled mounting flanges eliminate fume or condensate leakage. Choice of to tally-enclosed, ventilated or. corrosion' resistant bearing assembly. Factory-ap plied coatings sue available for severe corrosive applications. Sizes: 16 to 60 inches. Capacities: 2755 to 85,000 cfm. Request Bulletin 620. TYPE BV Vaneaxial A highly efficient pressure fan that combines airfoil propeller and guide vanes. Fan bearings and motor are completely isolated from the air stream, thus making these fans suit able for handling dangerous or damaging exhaust. Rolled steel drum and belt tube are welded airtight for complete protection. Also available in direct drive. Sizes: 16 to 30 inches. Capacities: 1260 to 20,000 cfm. Request Bulletin 795. .  218 Air System Equipment >, (RejzxL Unit-Fans, Inc. 501 N. St. Patrick St., New Orleans 19, La. Manufacturers of Axial Flow Air Moving Equipment for Industrial, Commercial and Residential Use ROOF VENTILATORS COMMERCIAL RATING: Blade Diam--12 in. to 36 in.--sheet metal blades. Air deliveries to 12,000 cfm, static pressure to Vk in. . INDUSTRIAL RATING: Blade Diam--12 in. to 60 in.--cast aluminum blades. Air deliveries to 75,000 cfm, static pressures to 4Vi in. wg. Available direct and belt driven, heavy gage used throughout, fan section insulated from housing, hood easily raised from either end. EXHAUST FANS Blade Diam--12 in. to 60 in. Air Deliveries to 100,000 cfm. Static Pressures to 3 in. wg. Sturdily constructed for heavy duty performance. BELT DRIVE TUBEAXIAL FANS Blade Diam--12 in. to 60 in. Air Deliveries to 75,000 cfm. Static Pressures to 4H in. wg. Cast aluminum alloy air foil blades> all welded con struction, special finishes available. DIRECT DRIVE TUBEAXIAL FANS Blade Diam--12 in. to 60 in. Air Deliveries to 75,000 cfm. Static Pressures to 6 in. wg. . Cast aluminum alloy air foil blades, all welded con struction, special .finishes available. Fan Housings are of heavy gage steel, all welded construction. Impellers are of cast aluminum, Air Foil section of an unusual design which permits variation in both number of paddles and angle of attack. This unique fea ture makes it possible to tailor the fan to any exact air moving requirement within the ranges indicated. It also enables the manufacture of a truly reversible fan to give equal performance in either direction of air flow. Air System Equipment Rlwa WfcaeD 219 Revcor, Inc. 251 Edwards Street Carpentersville, Illinois Phone: HAzel 6-4819 ENGINEERS AND MANUFACTURERS OF SINGLE AND DOUBLE INLET BLOWER WHEELS, PROPELLER FANS, HOUSINGS AND INLET RINGS Revcor Blower Wheels are available in a very large selection of sixes. 20 diameters of Single and Double Inlet Wheels from 3 in. to 12% in. Single inlet widths from 1 in. to 6 in. Double inlet widths from 2 in. to 12 in. Individually attached, thin gage, full width blades eliminate air obstructions at the ends. Blades are attached to end rings by Revcor's time proven, tab locked method. BLASTAIRE DESIGN Engineered to provide outstanding per formance. Ruggedly made for all appli ance applications. Available in steel and aluminum. Unique Blastaire production methods result in lower costs while main taining high standards of rigidity, strength, balance and performance l Individual Blades of correct curvature, number, depth and blade angle to de liver the greatest amount of air, effi ciently and quietly. Full Width Blades with a blade tip di ameter substantially the same as the outside diameter of the wheel deliver the m"rirrtfm air and pressure for the space dimensions required. Blade tips are securely locked to the back plate and ring. Embosed back plate pro vides rigid support for blades and hub. Hubs can be mounted either inside or outside the wheel. NEW DOUBLE INLET BLASTAIRE DESIGN Features single center disk construction. Blades extend through slots in the center disk and are locked tight to the center disk by a unique patented method. Provides more air and pressure in less space. ' HOUSINGS ' Sheet metal housings die formed to in sure custom-made uniformity at mass production prices. Readily permit adap tation of larger size wheels when required by space limitations. INLET RINGS Scientific Bell Mouth Venturi design as sures least resistance to air flow. Die formed for consistency. Sizes for all Revcor Blower Wheels. Also available in special sheet metal shapes. PROPELLER FANS--SIZES RANGING FROM 6 IN. TO 48 IN. Revcor's expanded fan line offers you a broad range of fas types for almost any sir moringspplicstion. Fill your i&o needs from the following types: Static Pressure s' Series, Price Saver (All Purpose) Series^Space Saver^Senes,"Hurricane'Series,^Multi----------- --Blade Pressure Series, Hi-Static Series, One Piece Series, Attic Fan Series. Slinger rings are available for most types. CATALOGS AND DESCRIPTIVE SHEETS AVAILABLE Containing technical details, diagrams, specifications, performance ratings, sixes, etc., of all Revcor Blower Wheels, Propeller Fans, Housings and Inlet Rings. Write Direct to: REVCOR, INC., Dept. R-l 251 Edwards Street' * Carpentersville, Illinois  220 Air System Equipment fu 4 bi< SHELDONS ENGINEERING LIMITED GALT, ONTARIO, Montreal, Toronto, London, Ottawa, Hamilton RapresnttlW9 In all principal cities across Canada AIR HANDLING APPARATUS No one Fan type can do all things. Sheldons since the year 1896 have. designed and engineered the com plete line of products to move and condition air. Sheldon products are accepted as "EQUAL" to any simi lar apparatus produced on the ' American Continent. When planning your projects in Canada we invite your inquiries for specifications and complete infor mation on SHELDON Air Handling Equipment. Consult our engineers. They are experienced and familiar with all requirements apt to be met in the Canadian field. Multi -Zone Units Mill Exhausters Pressure Blowers Unit Heaters Air.Conditioners Air Washers Air Conditioning Units * Keith Fans Silavent Fans Utility Sets . Forced Draft Fans Induced Draft Fans Airscrew Fans * Vaneaxial Fans * Medium Blowers and Ex hausters Mill Exhausters Dust Separators and Collectors Dust Filters Centrifugal Blowers Unit Heaters * Drying Equip ment Chemical Plant Fans Mine Ventilating Fans Complete engineering data and catalogs available upon request Air System Equipment ..JEJmST" 221 THE TORRINGTON MANUFACTURING COMPANY TORRINGTON, CONNECTICUT VAN NUYS, CALIFORNIA OAKVILLE, ONTARIO TOTAL COVERAGE Torrington offers the most complete line of fans in the United States. Applications range from small precision fans for electronic cooling to the largest heavy-duty requirements of industrial and residential air moving--in diameters from to 52". Torrington blower wheels are available in diameters from 1M" to 16". A full range of designs includes standard single and double inlet Airotors, in both continuous and individually'* bladed construction. In complete blower units, Torrington offers proved-out performance ratings on three full lines, the Vari-Basic line of belt driven and direct drive units, plus the revolutionary new mixed flow Radiax blower. The result is total cove&aqe--the best "problem insurance" you could have. For complete data: Taik'io Tbmnpton/  222 Air System Equipment fb> ud TRADE-WIND MOTOR FANS, INC, Division Of Robbins & Myers, Inc. 7755 Paramount Place, Pico Rivera, California TRADE-WIND VENTILATORS EXHAUST VENTILATION FOR HOME KITCHEN, LAUNDRY, BATH, DEN AND OTHER SMALL ROOMS SPACE SAVER KITCHEN VENTILATING HOODS Concord, antique copper New high style hoods with built-in under hood ventilator. Takes up no cabinet space. Touch-Bar controls dual lights and 3_gpeed ventilator. Two oversize deanable filters. Built-in back draft damper. 3W in. x 10 in. duct sire. 30 in., 36 ul, 42 in. and 45 in. hood lengths. PRE-WIRED HOODS Salem, antique copper MoDtecito, brushed copper Newport, stainless steel For cabinet installation only. Two inlets, one over stove, second at ceiling level, each with washable filters. Twin cen trifugal blowers. Built-in back draft damper. Duct size 4 in. x 13 in. F^fnitifiilly designed. For use with models 3501, 2501 or 1501 ventilators shown at right. Hoods are pre-wired with cut outs for ventilators at right, left or center. Touch-Bar controls dual lights and 3-speeda. 30 in., 36 in., 39 in., 42 in. and 48 in. lengths. c PATRICIAN VENTILATING HOOD Coppertone Satin Chrome Complete pre-wired package with axial flow fan, light, switch and filter. 30 in., 36 in, 39 in., 42 in. and 48 in. lengths. OVEN VENTILATING HOOD Ventilator only available; also 3 hood styles-- Newport, stainless steel Montecito, brushed copper Salem, antique copper For use with Trade-Wind hoods or for ceiling installation. . Handsome new style grille. Built-in back draft damper. Model 2501 for rooms up to KMX) cu ft. Model 1501 for 1000 cu ft. Duct taze ZV* in. x 10 in. Drawer-type filter available Full 300 cfm. High-etyle grille. Installs in ceiling or cabinet. Duct size 7 in. round. 50 watt motor. For bathrooms, 2-75 watt lamps, 100 cfm ventilator. Built-in .back draft damper. Duct size 4 is. round. 50 watt motor. For built-in gas and electric ovens. Pre-wired with switch nH automatic thermostat control. Snap-in filter; built-in back draft damper. 24 in, 27 in, 33 in. and 45 in. hood lengths. 3V4 in. x 10 in. duct size. 100 cfm, specially built for bathrooms. Duct size 4 in. round. SO watt motor. Built-in back draft damper. Air System Equipment bu. 223 Air Products Cleveland 2, Ohio Viking Blowers Solve These Design Problems Interchangeable Parts . >. many of the important features of Viking Blower Assemblies available in these component parts: New Mark III Bearing is factory-packed but de signed to permit the addition of oil; New Quadruped Bracket reduces noise possibilities and strengthens blower housing; New Center-Disc Non Flexing "B" Wheel is engineered for strength; and Universal Lock-on Feet designed to require a minimum of assembly time. Interchangeable Blowers . . . in performance, dimensions, belts, pulleys and air patterns. Viking's "B" Blowers meet A.G.A. requirements as acceptable substitutes for "A" Series Blowers without A.GA. retesting and without design or specification changes by manufacturers. Also has Universal Blower quick-assembly features. Viking "B" Blower (with centerplate wheel) 9 in.; 10 in.; 12 in.; 15 in. and % widths. Lighter loading, longer life Machined journal cuts shaft cost Interchangeable with conven tional Bearings Factory-packed, but may be re-oiled Possible Positions with Lock-on Feet DOWNBLAST Cost Reduction . the Lock-on Feet and multiple mo tor positions of the Viking Universal Blower Assembly reduce inventory, eliminate dead blower stock, cut lead-time needed in ordering and - reduce, initial-cost.-Parts designed. . to permit quick assembly. X- 6000 Leak-Proof Humidifier . . . New ovenware glass pan eliminates leaks, corrosion and rust common in old-fashioned humidifiers. Com pletely automatic unit. Space Restrictions . . . New Viking Direct Drive Blowers are available for application where space is at a premium. Viking "U" Blower (with end supported wheel) 9 in.; 11 in.; 13 in Full and % widths  224 Air System Equipment WESTERN BLOWER COMPANY Main Office and Plant: 1800 Airport Way, Seattle 4, Washington Sales Offices in the Principal Cities West of Rocky Mountains 1. TURBINE MULTIBLADE FANS--forward curved blade, Type TR, or backward curved blade, Type "S" fans for heating, wntiuting ffifthmi'1'8' draft, etc. Bulletins No. 80 & 81. 2. SPIROVANE PROPELLER FANS--furnished either di rect connected or V-belt driven for commercial or indus trial ventilation. Bulletin No. 60. - 3. TURBINE UTILITY SETS--v-belt driven, slow speed, quiet operating, for general utility duct ventilating sys tems. Bulletin No. 81. SERIES 59 UTILITY SETS--for general exhaust sys tems Complete packaged units. Bulletin No. 69B. 4. RB VOLUME & PRESSURE FANS--radial blade type either direct connected or V-belt driven for ventilating and conveying applications. Bulletin No. 89A. 5. WESTERN UNIT HEATERS--vertical or horizontal, for general beating and drying applications. Bulletin No. 68. 6. AIR WASHERS--for cleaning, cooling, humidifying and dehumidifying. Bulletin - No. SO. 7. VOLUME HEATERS--with one or more centrifugal fans for heating, ventilating and air conditioning. Available in vertical or horizontal cabinet units, or Multi-zone Units with zone dampers. Bulletin No. 70. 8. TURBINE ELECTRIC VENTILATING UNITS--direct connected for general ventilating systems. Bulletins No. 80 & 81. 9. OLYMPIC HEAT EXCHANGERS--Converters, Side Arm Heaters, Immersion Heaters, Oil Heaters, and Condensate Coolers. __ 10. HIGH PRESSURE BLOWERS--to furnish air at high pressure for gas and oil furnaces, flotation separators, blast drying, and cupolas. ____ _ 11. WESTERN SPECIAL & WESTERN SLOW SPEED PLANING MILL EXHAUSTERS--single or double for general mill exhaust; and material handling. Bulletin No. StA. 12. SERIES 59 ROOF YENTILATORS-J-Slow speed wheel. Forward curved blades. Motor, shaft & bearings out of air stream, all resilient mounted. Complete weather pro tection with automatic louvres on discharge of unit. Bul letin No. 69C. Bulletins as listed above furnished upon request 98 Air System Equipment rut ud bu. Westinghouse Electric Corporation 225 Mfllfl Office Slurievan! Division Heating, Ventilating, Cooling, Dehumidifying, Electronic Air Cleaning and Mechanical Draft Equipment Boston 36^ Mass. Offices in Principal Cities air handling products Centrifugal Fans with Airfoil Blading--Standard ised General Purpose and Heavy Duty Fans for both commercial and industrial applications. Capacities up to 700,000 cfm, all pressures up to 45 in. wg. AMCA pressure classes I, II, HI, IV.- Axial Flow Fans--V-belt driven or direct connected: Designed to provide low cost fume and vapor exhaust and air supply with new high efficiencies. Easily in stalled in ductwork. Vaneaxial, Tube-axial and Spraybooth types available for wide range of applications in all industrial fields. Ventilating Sets--Direct connected units for maxi mum efficiency at popular motor speeds. Manufactured in six sizes up to 3200 cfm. Compact V-Belt driven units for large capacity and quiet operation. Fourteen sizes up to 21,000 cfm. . Air Distributing Units--Air Conditioning, Sprayed Coil and Multizone; Heating and Ventilating, and Venti lating Fan Units. Factory built, unitary assemblies. Horizontal and Vertical. Coils available for Chilled Water and Refrigerant; steam and hot water. AllUnits available with "In-Line" PRECIPITRON Electronic Air Cleaners. Capacities up to 48,000 cfm. Cooling and Heating Coils--coils are available for direct expansion refrigerants chilled or hot water and steam. Water Coils in continuous tube or removable header type. Steam coils in standard, heavy duty, and steam-distributing types. jCoils feature Air-Activating Plate Fins. Surface Dehumidifiers--For central plant air condi tioning. Sprayed coil units-are available with chilled water or direct expansion refrigerant coils. Available with water spray and recirculating system, eliminators. Capacities to 250 tons of refrigeration and 62,500 cfm. Industrial Heaters--For heating of manufacturing areas, warehouses, garages and similar industrial and commercial buildings. Also for continuous duty heating in industrial processes with heavy duty wrought iron coils. Capacities to 4,500,000 Btuh, 32,000 cfm. Cabinet and Propeller Fan Heaters--Available for steam, hot water. In horizontal and downblast models. Capacities range from 15,000 to 684,000 Btuh, 240 to 11,000 cfm. Gas-Fired Unit Heaters--Propeller and blower type. Used with Natural, Mixed, Manufactured, L. P. Gases and L. P. Gas-Air mixtures. 25,000 to 250,000 Btuh. 400 to 3,600 cfm. ts-amt) ' All Purpose Centrifugal Fan--Catalog 1121 Axial Flow Fan Catalog 1110 Ventilating Sets--Catalog 1160 Direct-Connected V-Belt Drive Air Distributing Unit Catalog 1600 Electronic Air Cleaner "In-Line" for Air Distributing Units-- Catalog 1636 Cooling and Heating Coils, with Air Activating Plate Fins Catalog 1700 Gas Fired Unit Heater Catalog 1325 Surface Debumidifier X Catalog 1660-2 Industrial Heater Catalog 1510 Steam & Hot'Water Unit Heater Catalog 1500  226 Air System Equipment THE AMERICAN WARMING AND VENTILATING CO. = WAY 1017 Summit Street Toledo 4, Ohio CHerry 3-7151 "Quality Air Control Equipment" LOUVER Architectural type louvers having an unbroken line regardless of the length of the run compliments to day's contemporary design. A new principle of blade supports make the unit possible. AIR CONTROL DAMPER A new development, center pivot balanced linkage takes unnecessary torque from the operation of air control dampers. This new linkage' is located out of the air stream thereby eliminating unnecessary turbulence. FIRE DAMPER A new key slot locking device now insures tight and positive closing of fire dampers. - - -LP-SERIES------ROOF VENTILATOR DOOR LOUVER An entirely new engineering devel opment makes possible door louvers of exceptional strength and blade alignment yet keeping cost to a minimum ' A recently perfected rotary leverage principle, for motor and manual operated, shutters makes possible free and easy opening yet when closed the shutter blades seal tightly against one another to repel weather. This new quality roof ventilator eliminates the necessity of many types, for its design encompasses universal application and functions either for air exhaust by gravity or power, air intake by power. One style unit now does every job. Air System Equipment . 227 Elgo SHUTTER & MANUFACTURING COMPANY 2738 West Warren, Detroit 8, Michigan--Phone Tyler 8-0637 AUTOMATIC WALL SHUTTERS STATIONARY SHUTTERS BACK-DRAFT DAMPERS New! Extruded Aluminum Shutters with Completely Concealed Pivot Pins Lightweight--Strong--Durable The new Elgo Extruded Aluminum Shutters give you shutters of modem design. They meet the demand of your customers who insist upon attractive, lightweight, strong and durable shutters. The distinctive appearance of Elgo Aluminum Shutters blends with aluminum doors and windows. Your customers will also like the rust proof and non-corrosion qualities of Elgo Aluminum Shutters and, the fact that Elgo Shutters do not need paint to protect them from the elements. The weather strip and extruded frame are one piece unit construction. All pivot pins are completely con cealed. This gives you positive pivot pin action and prevents rusting, which means--no rust stains to mar the beauty of the frames. The full weather strip gives you ample protection'from back-drafts, rain, snow, dust and other hazards of the elements. AUTOMATIC WALL SHUTTERS ELGO shutters give you all these advantages . . . e Light Weight - Full Weather Strip Low Freight Cost Easier Installation Concealed Pivot Pins Rust Proof and Corrosion Proof Aluminum Natural aluminum finish with fluted frames. --Types-of Shutters--Steel or Aluminum Frame Automatic Shutters Automatic Back-Draft Dampers Stationary Shutters Hand-Operated Shutters Unit Blower Shutters Motor-Operated Shutters Automatic Ceiling Shutters Automatic Ceiling Dampers Motorized Ceiling Shutters - Hand-Operated Ceiling Shutters Write for complete specifications. CEILINC SHUTTERS BACK-DRAFT DAMPERS 228 Air System Equipment Colt Ventilation of America, Inc. 4-652 Hollywood Boulevard, Los Angeles 27, California Telephone: NOrmandy 2-1181 In England: COLT VENTILATION LTD SURBITON SURREY Telephone-. ElMBRIDGE tell . Agents in: Australia, Belgian Congo, Belgium, Burma, Cyprus, India, Indonesia, Madagascar, Malaya, Mauritius,.New Zealand,Pakistan, Portugal, Rhodesia and Nyasaland, South Africa and West Indies. The Colt System of Customized Natural Ventilation Colt Clear-Opening Ventilators for roof or wall--completely weather- ' proof - STANDARD AG/CO VENTILATOR manufactured in various rises. Width can be varied to fit non-standard width of glazing. COLT AG/CO/2046 comes complete with built-in control, endless control cord. Heavy gage anti-corrosive hardened aluminum, weight 23 lb. COLT AG/CO72446 same as 2046 except dimensions (see chart), weight 27 lb. GIANT CLEAR-OPENING VENTILATORS (AG/CO/4060, 4460, 4080, 4480) designed for use where large quantities of heat or smoke must be removed from a small "hot spot." Can be fitted into roof for ex traction or at low level for air inlet. All ventilators can be operated in dividually or alternately in batteries from one control point. TYPICAL DIMENSIONS OF COLT CLEAR-OPENING VENTILATORS Type A B CD F C H AG/CO/204Q AG/CO/2446 AG/CO/4060* AG/CO/4460* AG/CO/4080* AG/CO/4480* 2,0* 4'6* 1' 1- T 3' 2'4* 4'fi' 3' 3' 4'ft* 6'0' 1' 1' : 4J' 4'4' fl'ir r 3' 4i' 4'O' K'O' r 1' S*; 4f' 4'4' S'O* 3' 3' 8T 41' 4'0* 3' 41' 41' 41' These Ventilators are designed on the same principle but have manual control bar only. Can be supplied with manual PaeNTEiCaIONS: 650372, 19577/55, 10630/55, 114569, 16504/54. Other U.S.A., Canadian and Foreign Patents Pending. . . Colt Inflow Units---- Supply and Recirculation Powered ventilators for air intake. Fitted with Recir culating Dampers for recirculating heat within the premises. Can be fitted with filter unit to remove dust and dirt. - PRINCIPAL DIMENSIONS Type . 2 <s AG/RIU 15' Roof Inflow AG/RIU 18' Roof Inflow 2'2' 2'CT l'4i' l'4p 3'4* 2'6' 2'0* I'M* 1'8J 4'cr PATENTS: 718740, 645813, 661775, 506552, 2626556. Other J- U.S.A., and Foreign Patents Pending. All ventilators available from stock SSCTONTOKJ VtMTIATOft. Saw-Toothed Roof Ectcrier Cowling. Fining flange. S1mv for U.D.C- McSrcalolioB Dadiofl. Sleeve for U.D.C. Variable AA FiUftder (V.A.f4 qm< vtuiuiMi * Colt Ventilation of America, Inc, 229 The Colt AG/SR Ventilators for Hot Industries Positive, all year 'round, all-weather controllable ventilation, guaranteed regardless of wind conditions. No back draft from adverse winds provided inlet is balanced to extracts. With or without controls. Designed on aero-dynamic principles embodying aerofoil curves which harness and control the free power of wind and roof eddies. Combined with power of convection currents within building, ventilators cre ate a suction resulting in power of extraction equal to that of mechanical means without disadvantage of noise, wearing parts or operating or maintenance costs. Design effectively prevents rain from entering building. PRINCIPAL DIMENSIONS Type A B cD E F G H J K t U AG/SRC 2046 AG/SRC 2060 AG/SRC 3080 2'0' W 4' 6' 3'ir 2'4l' I'M' 2*0' 5*2' 4' 6' 5'S' 3'0* 7*0* 6' 6' 7'2J' 2'41' 4'0* I'M' YY nr l'9f' 6' 2'0' 4f* 2' PATENTS A APPLICATIONS: 567801,610934,727817,166533, 19576/55,10631/55, 114568. Other U.S.A., Canadian and Foreign Patents pending. AlA File Numbers: 12-K, 30 D-l, 14-U Colt Dual Purpose* Smoke and Heat Exhaust Ventilator COLT AG/COF/2046 Ventilator in COLT AG/COF/2046, 4060, 4080. Each ventilator fitted with automatic release in event of fire. Immedi ately removes smoke and heat, conforming with re quirements of International Fire Services who state that "proper fire venting is the key to the prevention of spread of fire once it has started in an industrial building." Fusible link can be designed to trigger venti lator open at any predetermined temperature. * Also a day-to-day usable ventilator with manual controls as described under AG/CO Series on opposite page. Specifications same as AG/CO Series. SECTION THRU VENTILATOR EXTERIOR VIEW l" for dwetinq,1 Typical arrangement of COLT AG/COF/2046 DDAL PURPOSE FIRE VENTILATORS COLT AG/COF/2046 Dual Purpose Fire Ventilators for flat or shallow pitch roofs for free Technical Manual No. AG5. Complete engineering data, sizes  230 Air System Equipment Allen Cooler & Ventilator, Inc. Rochester, Michigan See Sweet's Catalog for further detaiJs Representatives in principal cities Write to factory for catalog Air System Equipment * EXHAUSTERS BELTED ROOF EXHAUSTER 231 Ammerman Co., Inc. Stillwater, Minnesota Exhausters Powered or Gravity Underfloor and Overhead Exhaust Systems BACKWARD CURVE DIRECT CONNECTED ROOF RELIEF EXHAUSTERS "I-LINE" LOW SILHOUETTE ROOF FAN Allen "I-LINE" Roof Fan is designed to meet the architect's demand for an .attractive silhouette and the engineer's demand for high efficiency. This is ac complished by use of a circular spun steel hood, and venturi, with baffle so arranged in relation to the pro peller as to provide maximum efficiency with mini mum over-all height. Its appearance and quiet performance recommend it for new or old construc tion, such as schools and offices as well as industrial plants. It is easy to install (no extra base required) and it is easy to lubricate and clean. Available with Direct Drive (420 to 45,000 cfm) or with Belt Drive ' (4,000 to 31,000 cfm). Special units available to 70,000 cfm. ALLEN STAXAUSTER for Conversions or New Construction Allen Staxauster is a simple, compact, sturdy unit that be used to convert all types of roof venti lators into powerful exhaust or air supply unite. It -is available in a. wide, range of sizes and capacities to solve almost any ventilating problem, with either- Direct Drive or Remote Drive, as shown below. . "T-TYPE" LOW VELOCITY ROOF FAN Allen "T-TYPE" Ventilator is designed for low, one-story, flat-roof, modern buildings. It blends well with modem exteriors and its design and construction assure high efficiency, easy installation and low main tenance. Model T-9 has capacity of 420 cfm at 0 in. SP; Model T-16, a capacity of 600 cfm at 0 in. SP. Low height enables these units to be used for both roof and wall installations. HIGH VELOCITY VERTICAL DISCHARGE FAN Allen Type "VD" Roof Fan is designed for use where extremely high discharge velocity prevents the tendency of fumes to short circuit back through build ing openings. Fabricated of prime zinc-coated iron sheet, welded construction throughout. Automatic wing dampers open with air-blast, close weathertight when not operating. Available with Dircct Drive, with motor readily accessible, or Remote Dnve, with motor in outside housing and enclosed V-belt drive. Ca'pacities available-to.90,000 cfm._________ __ ________ REMOTE DRIVE STAXAUSTER for Corrosive Fumes Alien Remote Drive Staxauster is specially de signed for applications handling fumes, and/or high temperature air. Motor and belt drive are completely isolated from the air stream. ALLEN TYPE C TURBINE VENTILATOR Allen Type "C" Turbine Ventilator is wind driven and economically removes heated air, fumes and dust. Other Allen turbine-type ventilators indude powerdriven models for ventilating in calm jut conditions. "BCB" Lo-Boy Non-Overloading Centrifugal Wheel. Capacity table offers a selection of 16 wheel sizes-- 204 constant speed combinations with tip-speeds as low as 2000 fpm. Unit is exceptionally low in height. Standard construction consists of welded structural frame. Write for special engineers - bulletin ``BCD'' Non-Overloading Roof or Wall Exhauster. Designed for op timum performance at lowest pos sible velocities, reduces noise level to an absolute minimum. Motor directly connected to dynamically balanced- wheel eliminates costly maintenance. See Sweet's file for further details "RC" is regular Airxpeler design-- but spun from one piece of metal. Throats may be round up to 42 in., square or rectangular up to 34 in. Constructed to accommodate any size roof opening. May be used as gravity vents. Write for Bulletin. UPBLAST ROOF EXHAUSTERS POWER ROOF EXHAUSTER. DISAPPEARING EXHAUST SYSTEMS "PB" or "PFAS" Lo-Boy Wall or Roof Units. Efficient and quiet op eration for low static pressures up to Yi inch. Rubber grommets, are installed around all points where metal contacts metal. Powdered fresh air supply units on "PB" ex hauster with reversed pressure blade to bring fresh air in under power. Under the Floor and Overhead ex haust systems for all makes and models of cars and trucks. Will accommodate flexible metal hose up to six inches in diameter. Write for Bulletia No. 650H. Designed for immediate heat, smoke and fume expulsion. Split disc damper that automatically opens when fan is turned on provides weather proofed units. Direct drive units equipped with totally enclosed ball bearing motors. Belt driven units furnished with motors out of line of airflow in separate weather proof compartment. Write for Special Bulletin 232 Air System Equipment ^ VeotJ THE G. C. BREIDERT CO. P.O. BOX 1190, San Fernando, Calif. Representatives in All Principal Cities POSITIVE VENTILATION GUARANTEED... NO MATTER WHICH WAY THE WIND BLOWS! HORIZONTAL DISCHARGE ELIMINATES DOWN-DRAFTS! Breidert AIR-X-HAUSTER... famous gravity-flow ventilator developed from principles of aerodynamics; proven by years of use in all types of application. Transforms winds from straight-downward to SO de grees upward into positive suction--without a single moving parti Trouble-free, maintenance-free, weather proof. Guaranteed backdralt-proof, barring internal negative pressures. ' . NEW! SPECIAL VENTILATORS FOR FORCED-AIR SYSTEMS! Breidert POWAffi-X-HAUSTER... Unique power unit provides pleasing, unobtrusive appearance on top of any roof. Discharges air on a straight horisontal plane--preventing conventional back pressures and roof deterioration caused by dovmward discharge of ordinary power ventilators. Downdraft-proof against winds from any direction when fan is off (barring in ternal negative pressure). Operates as a gravity venti lator when power is off] MORE VENTILATION PER DOLLAR! Breidert uAIR-OUT" ... now available to meet the special requirements of forced-air duct systems. It's the same low-silhouette Powair-X-Hauster head (at left) without motor and fan assembly. Specially de signed to provide an internal static resistance much lower than that of ordinary discharge heads. Like the Powair-X-Hauster, the new Air-Out discharges fumes horizontally--and boasts an architecturally-pleasing appearance to enhance any roof top! INSIST ON CERTIFIED CAPACITY RATINGS BASED ON VARIABLE WIND CONDITIONS--This is your assurance that the ventilators you specify will perform efficiently in actual use*. Capacity ratings 'of It takes fewer Breidert ventilators to do the job than conventional verttitutors of the same size* OR use the same number of smaller-sise Breiderts to do the job of conventional ventilators. Breidert ventilators are certified by Pittsburgh Testing Laboratory. Breidert POWAIR-X-HAUSTERS carry the Certified Rating Seal of the Air Moving and Con ditioning Association. Breidert single-phase power roof ventilators also carry Underwriters' Laboratory ap proval. WRITE FOR ENGINEERING DATA BOOK--44 pages of installation photos, certified capacity ratings, complete specifications. Air System Equipment Air Vents IU*I Tollwn Hirschman-Pohle Co., Inc. Since 1908 200 Lent Ave. LeRoy, N. Y. Sales Representatives in Principal Cities Manufactuers of all types of Power and Gravity Roof Ventilators 233 New Low Profile Electric Ventilator Type "CK" The Type "CK" LOW PROFILE STATICK Power ventilator shown has been designed in response to the demand for the ABSOLUTE MINIMUM IN OVERALL HEIGHT for a ventilator using backward curved blade centrifugal fan, and is available in a wide range of capacities either direct or belt driven, with or without dampers or other extras as needed. The same LOW PROFILE type of bousing is available using a propeller fan, or for gravity, pres sure relief or intake. The latter is available in oblong shapes or sizes as may be needed, with or without our Insulated Double Shell steel curb of one of the several standard types. Any or all of these ventilators subject to modification to meet the need of any building project. Type LAC STATICK Power Roof Ventilator This model features the damper housing as an integral part of the ventilator where the damper is ac cessible for cleaning. It shows the electric damper control mounted in the motor chamber where it is also readily accessible because of the hinged cowl. ' Our Type "LAC" STATICK Power ventilator designed for efficient exhaust at either low or high static pressure, using non-overloading backward curved blade centrifugal fan, available in many sizes for almost any required capacity. .. The Type "LC" STATICK Power ventilator (not shown) uses a similar construction minus the damper housing. Capacity ratings for belt driven sizes of the Types "LC" and "LAC" STATICK Power ventilators have been formally approved by Air Moving Conditioning Association, and carry their CERTIFIED RAT ING SEAL. 8ee Sweet's Architectural, Engineering, or Industrial Construction Files. Complete data on any or all types gladly furnished on request.  234 Air System Equipment juf <*d in v Jenn-Air Products Company, Inc. 1102 Stadium Drive, Indianapolis 7, Indiana Warehouse stocks in all major cities Roof Exhauster Equipment for Public. Commercial and Industrial Buildings QUIET-TESTEDI Jenn-Air Quiet-Tested Roof Exhausters are pre-proved under simulated field conditions. Each unit must pass rigid inspection by the critical Vibronic Eye ... is `'screened" in Jenn-Air's Sound-Elec Test Chamber to detect noise, vibration. ' Direct Drive Power Roof Exhauster Dependable U-Spring Suspension virtually eliminates noise caused by vibration. U-Springs suspend the power assembly, japlute it from the base. Motor and wheel are balanced together, eliminating vibration and noise. Heavy gage all aluminum construction. The Axial type Jenn-Air Roof Exhauster is recommended for general ventilation work and for duct-type applications where static pressures do not exceed one-half inch. Special Non-Over loading Design protects against motor failures. Dependable U-Spring Suspension eliminates noise caused by vibration. U-Spriags suspend the power assembly; isolate it from the base. Belt Drive Power Roof Exhauster In this Quiet-Tested Belt Drive Power Roof Exhauster, Posi tive Weather-Proof Engineering is combined with trim Low Contour Design. Full Bail Bearing Drive and Motor are mounted out of the air stream. Heavy Gage Ail Aluminum Construction gives strength without weight. Exhauster can be quickly, easily, disassembled for re-assembly on the roof. Non Overloading Blade, dynamically and statically balanced, also assures long life, smooth, quiet operation. ' Hi-D Centrifugal and Axial Power Roof Exhauster Centrifugal Wall Exhauster Jenn-Air Centrifugal Wall Exhausters eliminate most duct work ... provide a means of ventilation through the wall when roof exhausters would prove unsuitable or more costly, as in multi-etory construction. Constructed of heavy gage aluminum, exhausters are completely weather-proof, unusually quiet. De pendable U-Spring Suspension eliminates noise caused by vibra tion. U-Springs suspend the power assembly; isolate it from the wall. This exhauster fills the need for general area ventilation ... "has-a-clean-engineering-design, that,features compactnessand serviceability. The wheel (centrifugal) or blade (axial) is lo cated at the top, providing a high point of discharge which allows low curb construction. Housing is made of heavy gage aluminum which provides strength without weight. Bird guard of heavy gage stainless steel construction comes as an integral part of every unit. Unit opens easily for ready access to the drive assembly. Special vibration absorbers reduce noise to a minimum. Totally enclosed, full bail bearing, permanently lubricated motor assures smooth, uninterrupted service. Tubu-, lar drive assembly has permanently sealed, pre-lubricated ball bearings. Motor and drive can be serviced from interior of building, if desired. Jenn-Air Relief Vents-eliminate goose necks or hoods used for air outlets or intakes. Weather resistant spun aluminum construction. Member Air Moving & Conditioning Association Jenn-Air Exhausters are tested and rated in accordance with standard test code AMCA Plate V-A (centrifugal) and VI-A (axial) as adopted by AMCA and ASHAE Air System Equipment Muckle Manufacturing Co. 666 Belford Road Owatonna, Minn. Sales Engineering Representatives in Principal Cities 235 MUCKLE SPUN ALUMINUM--Rating free air de livery starting at 460 cfm on larger units up to 1 in. static. Unite may be had in backward curved wheels and propeller type blade. Heavy gage alloy aluminum .064 Motors are standard brands. Quiet, Sturdy, Low silhouette, Resilient mounted motors. MUCKLE VENTS--are excellent for moisture laden applications or corrosive conditions. Motor is located out of the air stream, and housing is hot dipped gal vanized after fabrication for lasting protection. Ca pacities 254 to 10280 cfm. Units very efficient at low static pressures. Constructed from heavy gage steel, electrically welded. MUCKLE LO-SIL--designed for low silhouette ap pearance. Largest unit only 25j in. high. Capacities from 225 to 17,600 cfm. Automatic back draft dampers built-in on all models. Vibration separators are pro vided to eliminate vibration and hum. Totally en closed, ball bearing motors are directly connected to propeller. MUCKLE BC VENT---Centrifugal backward curved wheel is fine for operation where static pressures are encountered. Non-overloading, dynamically balanced wheel, directly connected to totally enclosed motor. No maintenance of belts, pulleys, or bearings. Motor is out of air stream for protection. Capacities from 280 to 7650 cfm. Heavy gage construction. MUCKLE BELTED VENT--offers over 100 different capacities for any specific requirement. High exhaust capacity utilizes low fan tip speed to make unit very quiet in operation. Low in height, compact and sym metrical design, blends well with modern architecture. Heavy duty, ball bearing motors and non-overloading backwardly curved wheels used on all units. MANUFACTURERS OF POWER ROOF VENTILATORS FOR OVER 19 YEARS COMPLETE DATA FURNISHED UPON REQUEST  236 Air System Equipment B*f VvntUttt ENN VENTILATOR CO., Goodman above Allegheny Ave., Philadelphia 40, Pa. Representatives and Distributors in Principal Cities INC. Air System Equipment VatOmen WESTERN ENGINEERING & MFG. CO. 4112 Glencoe Avenue, Venice, California Representatives in Principal Cities 237 ESTABLISHED 1921 Penn Oynafan Monofactorert of ROOF VENTILATORS AND ACCESSORY PRODUCTS FOR PUBLIC, COMMERCIAL AND INDUSTRIAL BUILDINGS DOMEX -- V-balf and direct driven centrifugal fans in a weather-tight (pen aluminum bousing. Badcwardly curved statically and dynamically balanced fan wheel* with nan-overfooding characteristics. Over 60 capacity selection*. Bulletin DMXA-83. Hi-EX -- Straight through -- high velocity ver tical discharge air exhauster, -- streamlined housing. Certified capacities from 24,000 cfm to 60,000 cfm. Bulletin PH-UH. SONOTSOi CURB -- Bulletin SC-88 contain, data on Penn's roof curbs. Information per taining to extruded aluminum curbs as well as fabricated types b outlined- In most instances where a gravity or powered ventilator b used, a reef curb b abo required. Penn's acoustically and thermally insulated curbs are of superior quality and generally cost no more then field constructed curbs. TURBINE --Ball boarinJ'Net&ne ventilators are true rotary, air-driven suction turbines that work automatically 'and continuously without maintenance or operating expense. Boll bear ing action enables the slightest motion of oir-to move the rotor. Bulletin PT-24A. Write for ony or ail of the above illustrated catalogs PENN VENTILATOR COMPANY, INC. for More Thao 25 Years, The Bvilden Roof-Top line ' -* * Manufacturers of PROPELLER FAN, CENTRIFUGAL, STATIONARY and ROTARY RIDGE VENTILATORS Penn Ventilators are listed ia Sweets Architectural and Engineering files Charter Member AMCA Mechanical ventilation without power cost. Certified capacity ratings. Will not back-draft. Stormproof. Perma nently sealed ball bearing assembly with lubricant reservoir. Rubber ISO-mount ing- Baked enamel finish. High volume exhaust. Architecturally desirable. Fabricated in any length in 12 throat sizes to fit any roof. Storm- A stationary ventilator providing high exhaust certified capacity regardless of wind direction. Rugged construction. Rainproof and stormproof. Low sil houette. FORBES ECONOVENT VENTILATOR Rugged design. Engineered construction at a low pace. Certified capacity rat ings. Low silhouette. WESTERN AIROUT VENTILATOR Directional type ventilator. Moves in the direction of airstream for maximum exhaust power. Certified capacity rat ings. Balanced, rugged and stormproof. FORBES AMVENT VENTILATOR Government specification ventilator. Meets Corps of Engineers Guide Speci fications CE 220.09, October 5, 1951. Removable top plate. Optional bird or insect screen or damper. WESTERNAIRE VERTICAL EXHAUST VENTILATOR High capacity industrial "blow open" exhauster. Stormproof. Low silhouette. Prevents roof damage or re-entry of air in building. Fourteen gauge construc tion. WESTERNAIRE BOOSTER FAN Duct mounted fan installs between ventilator and base. For new or existing construction. Permits ventilator ex haust when fan off. WESTERNAIRE CURB . MOUNTED FAN Provides fan diameter same size as throat diameter for maximum exhautt. Available in 40 models. Capacities ba /id on NAFM ratings. See our complete Catalog in SWEET'S ARCHITECTURAL FILE, INDUSTRIAL CONSTRUCTION FILE and WESTERN STATES A-E-C CATALOG FILE  238 Air System Equipment * a?*d52? GrfD" AIR CONTROL PRODUCTS INC. 657 Center St. Coopersville, Michigan Air Conditioning Registers, Grilles, Diffusers--Celling and Baseboard Diffusers-- Commercial Registers and Grilles Air Syrt-m Equipment 239 AIR DISTRIBUTION PRODUCTS ADR 116 S. La Brea Avenue Los Angeles 36, California MULTI-TROL REGISTERS: Commer cial type with special butterfly "ShalloValve", so shallow it can be used with standard 3% in. fittings. Fully-adjustable face bars, with rolled pivots that can't pull out of frame. Single or double deflection types. Beige prime coat 6nish. Full range of types and sizes. Matching grilles, a]] sizes. No. 76 BIG CAPACITY CEILING DIFFUSER: Up to SO percent more capacity than ordinary round diffusers. Plenty of free area for use on ducts of same listed size. New "Air Flow" rings -deliver air at lowest resistance. Con toured anti-smudge outer ring. Sponge rubber gasket. Flush, Step-Down and Adjustable types--6,8,10,12 and 14 inch sizes. Beige prime coat. No. 90BIG CAPACITY CEILING DIF FUSER : Up to 40 percent more capacity than ordinary square diffusers. Same engineering, performance and appear ance advances ss No. 76. In Step-Down style only--6, 8, 10, 12, 14 ana 18 iD. NEW "STA -SET" DAMPERS in both round and square models have butterfly valve, nylon friction bearing and opera tor rod with Adjusto-Stop collar. . No. 120 SERIES MULTI-LOUVER REGISTERS: Commercial type with one-piece face, stamped fins in. wide. Great strength, large free area. Fins adjust for horizontal control of air pat tern. Multi-Louver valve for 45 deg downward deflection--any upward de flection. Removable operator handle. Adjusto-Stop. Beige prime coat finish. Matching grilles, all sizes. No. 40 FLOOR REGISTER: Features the famous Rigid-Lock type construction with each fret locked to each crossing ing fret and to margin. Dial-operator valves run the short way of the face. Medium mesh (Vi6 in-) between frets. Finished in Oak or Metafescent--all standard sizes. No. 41 FLOOR RETURN AIR GRILLES have same construction features. No. 20 SERIES AIR CONDITIONING REGISTERS: Positive control of air stream with vertical front fins, horizon-' tal back fins--both readily adjustable from face. Damper opens to full 90 deg. Adjust-Stop for balancing system at face. Models for sidewall, baseboard and inverted installation. 8 X 6,10 X 6,12 X 6,14 X 6 duct sizes. Matching griffs, all sises, plus 24 X 6 and 30 X 6. Two-tone beige finish. No. 188 BASEBOARD PERIMETER DIFFUSER: With built-in rotary damper to insure uniform velocity at face at any setting. 2-ft and 4-ft lengths with Adjusto-Bottom base strips. Both diffusers and matching grilles can be installed before or after plastering, on subfloor or finish floor. Also No. 170 BASEBOARD DIFFUSER and match ing grille for low-budget installations. ' No. 42 PERIMETER FLOOR DIF FUSER : Blankets outside wall with warm air, prevents drafts. Has one-piece face, extra-wide margins, smoothlycurved vanes and wafer-thin valve. Set vanes for any deflection witbout shearing off at ends. Opening sises 14 X 6,12 X 6, 14 X 4,12 X 4, 10 X 6, 10 X 4, 10 X 2Vi, 14 X 2Vi and 12 X 2$. Also No: ISO ECONOMY FLOOR DIFFUSER for low-budget installations. No. 15 SIDEWALL PERIMETER DIF FUSER : Rapidly diffuses warm air over outside wall without "scrubbing". Easily balanced at face. Sponge rubber gasket. Sises 10 X 6, and 12 X 6. Beige prime coat or Metolescent finish. "E" FRAME for baseboard installation. Also No. 16 OUT-OF-WALL DIFFUSER for use where stackhead and duct cannot be put in wall. WRITE FOR AIR CONTROL CATALOG FOR COMPLETE DESCRIPTIONS, ENGINEERING DATA, SIZES Three-Way Throw True 3-way distribution, no spillage Four-Way Throw 360 deg distribution High Induction S-4 SC-2 Two-Way Corner Complete 90 deg distribution Two-Way Throw Side throw balanced to area served S-2 One-Way Throw Side throw balanced to area served S-l ADP diffusers are designed and engineered for better air distribution. Greater free areas permit greater effi ciency. The unique but simple construc tion combined with hign induction characteristics result in top performance. The inner core assures a balanced air delivery over the collar and face of the diffuser. No blank-offs or baffles are re quired to meet special pattern or de livery requirements. ADP diffusers provide rapid temperature equalization with quiet, draftless efficiency. The greater -efficiency of ADP diffusers permit the use of smaller ducts and a material saving on installation costs. ADP diffusers are made in a complete range of sizes and face patterns. The air to be delivered may be proportioned in any required direction. The Type S frame, as shown, is standard, however, ADP diffusers are available with flat 'frames, tile replacement frames and with removable cores. ADP diffusers are fabricated of cold rolled steel and welded throughout. Large diffusers are made of aluminum. The standard finish is baked on silvertone enamel. Special finishes are avail able. The TOB volume control has true-op posed blades. The blades are pivoted at edge and orifices, remain constant. No contrasting velocities. Fine adjustment with fast action. ADP diffusers and volume controls have been thoroughly field tested. Thou sands of ADP diffusers are now perform ing with satisfaction in all types of in dustrial, commercial, residential and special applications. All ADP diffusers have a smart trim appearance to blend with the decor of todays modern construction. Sales engineering offices are located throughout the United States. They will welcome an opportunity to discuss your diffuser requirements. mnnsnGnncmsEsansnrri. iannnoanncHrccz?c:nc??s3ci i n c;c?Fia i - lnaEroncnccscr^r^coEi K-310 ADP manufactures a complete line of adjustable bar grilles, registers and volume controls. The "K" series shown above is available as a grille or register and in - single or double deflection with or with out attached dampers. The new frame design gives an im proved and attractive appearance and will add to any architectural treatment. The "K" series is fabricated of extruded aluminum and the frame is of welded construction. The solid section adjustable bars are of extruded aluminum and are spaced on $-in. centers and give top performance at a minimum noise level. A complete line of volume controls is available. Opposed blade dampers are adjustable through face of register with a removable key. - Dampers with individually adjusted blades are available. Extractors are manufactured for permanent setting or with key operation. ' We suggest you contact your ADP representative or write for catalog.  240 185 Madison Ave. New York 16, N. Y. Air System Equipment * r nutTM AIR DEVICES INC, ffiilBiR 1) registers and grilles high velocity units * punkah louvers air diffusers filters exhausters Representatives in Principal Cities AGITAIR DIFFUSERS Air Devices Inc. A complete line of Registers, Grilles and Scoops for all types of Industrial and Commercial air conditioning applications 185 Madison Ave. New York 16, N. Y. I1 11 Lll I HI I I Agents in All Principal Cities. 241 CUSTOM MADE DIFFUSERS AGITAIR square and rectangular air diffusers incorporate built-in diffusing vanes, scientifically arranged in unlimited louver patterns to provide draftless, noiseless air distribution in 1, 2, 3 or 4 directions from any ceiling or side wall location. These AGITAIR diffusers are custom made to suit each job condition and are available in three distinct types, "RC" with separate mounting frame and interchangeable diffuser cores; "R" and "RV" series, one piece units. Catalog R-107 contains dependable, accurate performance data. MR series matching return units (without diffusing vanes) are available in unlimited pattern designs, square and rec- tangular in shape to harmonise with AGITAIR supply, dif fusers. MR units are recommended only for return or exhaust applications. STRIPLINE SrntlPLINE slot type diffusers are slenderly designed, incon spicuous, practical and versatile. ' STRIPLINE combines the best features of both slots and efficient air diffusers to insure equalised air flow throughout the entire length of the diffuser, with . . . high rate of tempera ture equalisation . .. gentle secondary air movement. .. even temperature in area served . . . quiet operation. STRIPLINE is available in various widths (some only 2 in. wide) and stand ard 4 ft lengths which can be butted together for unlimited runs. STRIPLINE can be located almost anywhere to suit interior design--in walls, ceilings, coves, moulds, window re veals or stools. Catalog S-104 contains complete dependable engineering data. CIRCULAR DIFFUSERS AGITAIR circular air diffusers are made in two types--."O"-- non-adjustable and--"OA"--adjustable. The graceful lines of the spinnings are identical for both types. The "OA" adjustable units control the air direction at four different angles of discharge simultaneously. Air adjustment of these units is accomplished after installation and without changing the position of the spinnings- For normal ceiling dis tribution, Type "O" is recommended. Catalog C-101 contains all dependable performance data. PERFAIR Perforated Air Diffusers AGITAIR PERFAIR square and rectangular diffusers incor porate interchangeable cores available in unlimited air pattern arrangements for 1-, 2-, 3- or 4-way Wows. These units also include built-in air controllers for positive adjustment of air ' deflection after unit is installed. The perforated face plate of PERFAIR blends in naturally with acoustical ceilings. Match ing returns or exhaust units harmonize to enhance the archi tectural design. Separate mounting frames allow quick and easy installation of supply or return units. Catalog P-tOO con tains dependable performance data. THERMOTANK-AGITAIR PRODUCTS The AGITAIR diffusers illustrated on this page and the THERMOTANK products shown on page 242 are sold exclusively by representatives for Air Devices Inc. Complete engineering data, sizing and selection of these THERMOTANK-AGITAIR products are available from Air Devices Inc., 185 Madison Ave., New York 16, N. Y. See THERMOTANK INC. ad on page 242. DDY A double deflection grille affording four way diffusion --individually adjustable streamlined fins in. C.-C. heavy gage mot"! and sturdy construction. DVL A directional-type register employing 1 in. wide, parallel-acting valves. Face fins are individually adjustable right and left. The 1 in. wide, parallel-acting valve mechanism is available with any/all STEWART face patterns. DDVO A doable deflection grille with opposed action valves. The valve consists of a series of hollow, internally reinforced air-foil sections. Through a unique actuating mechanism each air-foil section turns in a 90 deg arc toward a similarly turning section. SCOOPTROL A device designed to deflect and control the air from a supply duct into' a collar, and installed at the junc tion of the duct and collar. Scooptrol is a double-blade func tional product, easily adjusted, positioned and then fastened by sheet metal screws; it cannot move or fall. DG An exhaust grille with non-adjustable fins. Fins are normally factory set at 45 deg down angle to restrict visioo. Also available with fins set at 0 deg vertical or horizontal. PLAIN LATTICE GRILLES Available in satio bronze, brass and aluminum. Also plated finishes on steel. FINISH DIRECTIONAL TYPE OUTLETS ARE PROTECTED BY A PRIME COAT AND A FINISHING COAT OF SILVAIR ENAMEL BAKED ON. SILVAIR FINISH IS A MODERN, ATTRAC TIVE COATING CONTAINING ALUMINUM PIGMENT, AND IS . SILVER-BLUE IN TONE. NO ADDITIONAL PAINTING IS REQUIRED.  242 Air System Equipment Air Conditionfat Units, Dtfumi. Ln<i Jke/moraNk 11191 Lappin Ave., Detroit 34, Michigan Toronto, Canada Glasgow, Scotland London, England Melbourne, Australia Hamburg, Germany Oslo, Norway Basrah,,Iraq Johannesburg, S- Africa THERMO-REG UNITS Thermo-Reg mixing aod sound attenuating chambers for high-reiocity air con ditioning systems, single or dual duct, are available as (1) ceiling type or (2) under window-type. CEILING UNIT Thermo-Reg ceiling units for rooms or corridors serve one direct connected AGITAIR diffuser or several remote dif fusers. They offer considerable flexibility to accommodate room modifications or changes in internal loads after installa tion. PERIMETER UNITS Thermo-Reg perimeter units, operating at a low sound level, supply conditioned air through the AGITAIR Stripline dif fuser in the top or front of each unit. In single duct systems, room conditioners are controlled by a zone thermostat. In dual duct systems, they are individually controlled by a thermqstat in the space served. Ask for Catalog TA-101. CON-VOL Equipped High Velocity Mixing Units CON-VOL, a unique device now available in all Thermo-Reg . Constant Volume perimeter and ceiling units assures preci sion control of air volume and temperature to meet all re quirements regardless of inlet static pressure variations. CON-VOL utilises flow regulators and standard pneumatic motors mounted on a sliding base. The entire system elimi nates the need of complicated linkages. DRUM PUNKAH LOUVRES These units are specially designed for those beating or ventilating applica tions requiring extremely long throw. These units are suited for installations where large spaces must be served with a minimum of duct Work. DRUM PUNKAH LOUVRES with directional air control and long throw are particu larly adapted to large spaces in indus trial plants, auditoriums and com mercial establishments. Engineering data available. ` .. ROUND PUNKAH LOUVRES .PUNKAH LOUVERS are nozzle-type outlets incorporating principles of high velocity air delivery with individual directional control for spot heating or cooling applications. These units are widely used in applications for ait con ditioning, beating and ventilating in ships, industrial plants, aircrafts, tele phone exchanges and a variety of other applications. For complete data ask for Catalog. THERMOTANK-AGITAIR Products illustrated on this page are sold exclusively by representatives for Air Devices Inc., 185 Madison Avenue, New York 16, N. Y. See Air Devices Inc. ad on'pages 210-211. "- - Air System Equipment Air DU!a*rm 243 M!R-FACTORSl 1624 South Raymond Ave. Air DistributionAir Control Monrovia, California SERIES B60 Ceiling Diffusers: MODEL MO-MJ (Series T) Patent! applied ter. Air-Factors' Model MO-MJ recessed, square and rec tangular induction type ceiling sir diffusers are designed to MODEL LCF-RC (Removable Core) comply with modern architectural tile ceilings and can be at Air-Factors' Series B60 Ceiling Diffusers for mounting on ceilings through patented construction provide propor tionately balanced air distribution with controlled air motion through laminar counter-flow cores. Square or rectangular air diffusing outlets with full range sizes and capacities allow maximum mixing of primary ana secondary air with distribu tion of supply air in direct ratio to floor area. ' tached and fitted to any standard ceiling structure. The dif fuser discharges supply air substantially parallel to the surface upon which it is mounted, inducing a large percentage of room air into the hooded section to mix with the supply air being discharged. On-the-job adjustment to the discharge angle is provided. One, two, three or four-way unbalanced or balanced air patterns are available. SERIES ACD DIFFUSERS: Air-Factors' Series ACI> Air Curtain Diffusers are de signed for ceiling installations where it is desirable to blanket a single Or perimeter exposed wall with a curtain of air. It may be used to curtain any area bordering a conditioned space. Special butt ends are provided for continuous strip installations from 1 in. to 4 in. in width. SERIES AVP-QO Adjustable Air Propor tioning Vanes: MODEL LCF-RC (Removable Core) Factory set outlets distributing air in laminar counter-flow layers mix supply with room air reaching design conditions in minimum time and space. LCF outlets can be equipped with secondary flexible horizontal vanes which may be reset on job, giving maximum, vertical control with varying length of blow. Balances air distribution for given supply outlet. Quick opening feature extracts air with a 2*4 in. maximum entrance into main duct, reducing velocity evenly over outlet face.-' Full shutoff. Manufactured separately or attached to side wall ceiling outlet or diffuser. Key or rod operated. SERIES OBD-KO Air Volume Control: Patents applied for.. Air-Factors' PAD Perimeter Air Diffuser provides for the perimeter system of air distribution. A register with built-in diffusing core. The core is factory set to distribute the air to reach comfort conditions in a minimum of time and space. The laminar counter-flow air deflecting vanes provide a maximum divergence angle to blanket a greater area of per imeter surfaces. The perimeter diffuser is provided with a dial operated volume control valve. ' Opposed acting blades; center pivoted. Operate from full open to full closed position. Used directly attached to grille, diffuser or installed as separate unit. Key operated. Friction linkage maintains blades m position when set. 244 Air System Equipment A-J Manufacturing Co. 3601 East 18th St Dept. Y Kansas City 27, Missouri REGISTERS GRILLES DIFFUSERS Grille, . ^mj Manufacturing Co. 245 Model 55 Diffusing Perimeter Register A-J Convector Grille and Register. These are custom-made to your specifications. Architectural grille of aluminum, muntz, stainless or cold-rolled steel covers adjustable bar-type louvers, single or double bank, to direct air flow in derived, pattern. Setting frame minimizes installation time. Construction elimi nates tampering after installation. A-J No. 55 Diffusing Perimeter Floor Registers. Heavy gage curved vanes are factory set to deliver a fan-shaped air pattern. Ideal for installation in stair risers, under kitchen cabinets, in picture window sills, or as side wall outlets with high velocity systems. Valve louvers may be set with special lock screw after system is balanced. A-J Architectural Grilles are available in slotted designs B, C, and Dt and square meshes of Vt, 34, 34. and 34 in. The grilles can be made to your exact order from steel, aluminum, bronze, monel or stainless. There is practically no size limita tion. See A-J illustrated catalog for specifications. A-J A-76 No-Vision Grille, shut-off type. It has extruded aluminum Y-bars and flange frame. Efficient in free area. Depth is 9i in. As in other styles of A-J no-vision grilles, the auxiliary frame telescopes over core from opposing side for fast, ample and neat installation. Spans IV4 in. to 2Vi in- depth. Cutaway view shows open and closed positions. A-J No. 400 Scries Air Conditioning Grilles and Registers. Extruded aluminum bar-type grille, steel frame. Single Or double bank adjustable; in horizontal, vertical deflection or combination of either. No. 440 styles have opposed blade damper. The No. 430 register has single hunt- of bars with multiple valve body, removable handle. All-aluminum faces on styles A-400 and A-440. A-J No. 42 Series Return Air Grilles. Available with either horizontal (42-H) or vertical (42-V) face bars on Vt in. centers. 45 degree deflection for minimized see-through. Overall, 134 in. beyond duct size; depth % in. All steel, gray prime finish. No. 432 has multiple valve body, removable handle; with op posed blade damper. No. 442. . A-J A-7000-B Grille. This extruded all-aluminum no-vision grille blends attractively with contemporary interiors. Extruded aluminum V-bars-(3 to the in.) and flange frame. Resists corro sion, rust. Lightweight, approximately 70 percent free area. Mitered comers. Auxiliary frame telescopes over core from op posing side for neat, finished appearance in doors or partitions. Span from 134 in. to 234 in. Grille % in. deep. A-J No. 77 Series Thin Core Grilles are only Vi in. thick, yet are completely sight proof. Approximately 30 per cent free area. With auxiliary frame, the No. 77 series can be installed in panels or partitions from 34 to 34 in. thick. TlhHt.ntjfn above shows grille and cut-away view of grille and auxiliary frame. No. 77-A is all steel with channel frame. Also available without framing--No. 77-C. A-J No. 200 Series Ceiling and Side Walt Diffuser. Available in a wide range of deflection patterns. Standard construction is steel frame with extruded aluminum, adjustable, curved face bars which are 1V* in. wide on 34 in. centers. Overall size is 134 in. greater than duct size. Approximately 75 percent free area. Aluminum enamel finish. No. 230 has register body, multi ple valves, removable handle. No. 240 is the opposed blade damper style. A-J No. 75 Grille. For dark room or other application which requires ventilation without light or sight. Steel construction throughout. Free area approximately 60 percent. With flange frame. No. 75-B; with channel frame, No. 75-A. Depth of No. 75-B grille, 134 in. Spans 334 in. with standard auxiliary frame. Non-epecuta black only. FOR COMPLETE SPECIFICATIONS AND PRICES ON ALL A-J PRODUCTS, WRITE FOR ILLUSTRATED CATALOG  246 Air System Equipment . Rcebten mi crfu THE AUER REGISTER COMPANY REGISTERS AND GRILLES FOR EVERY HEATING AND COOLING NEED 6610 CLEMENT AVENUE CLEVELAND 5, OHIO In Canada: Superway Products, Tilbury, Ontario Auer features a complete lice to meet every heating, cooling, or combination system requirement. The Auer line exemplifies correction of design ana construction--decorator styling-- easy installation. / PERIMETER HEATING, COOLING, OR COMBINATION SYSTEMS "PERFUSAIRE" "PERFUSAIHE" ... fits 2>i in. % 12 in. and 2K in. x 14 in. openings. Only 18 in. long and 4K'in. high, the "Perfus&ire" has spread ana capacity of 4 to 8 ft. units. "Limit-Lock" per* mita perfect balancing of system. No. 200. "FANAIRE" "FANAIRE" ... for high or low side wall installation. Efficient, low-resist ant, perimeter air diffusion. Sizes 10 x 6, 12 x 4, 12 x 6 and 14 x 6. AUER "DRP" FLOOR PERIMETER REGISTER AUER "DRP" FLOOR PERIMETER REGISTER ... for intricate, "narrow^ type" installations. Available with builtin Damper in 2%, 4 and 6 in. widths; 10, 12 or 14 in. lengths. "AIR-FLEX" SERIES "AIR-FLEX" SERIES . . . Wall regis ter, Grille bars and multi-louvers adjust able to direct air flow in all directions. Grille to match. No. 4432. "STREAMLINER" SERIES . . . For high velocity air-conditioning systems. Obtain maximum diffusion, silent opera-. . tion. SINGLE BAR MODEL: "Stream liner" Bars vertical in front, with hori zontal multiple louvers in rear. Louvers operated by lever on face. DOUBLE ' BAR: No. 1206 VH-OB--double deflec tion grille with 2 banks of "Streamliner" bars. Front bars vertical, rear hori zontal. Opposed blade damper louvres easily adjusted. ORNAMENTAL GRILLES ORNAMENTAL GRILLES . . . Com plete line available in steel, stainless steel, brass, bronze or aluminum. Large variety of decorator designs and finishes. WRITE FOR COMPLETE DESCRIPTIVE LITERATURE Air System Equipment Bututw Gmio 247 BARBER-COLMAN COMPANY 1300 Rock Street, Rockford, Illinois Field Offices m 95 Cities Throughout the United States and Canada--consult local phone book A Complete Line of Engineered Air Distribution Products Barber-Colmao air distribution products are engineered "to make air behave," to eliminate complaints: "Too hot--too cold--too drafty." They provide uniform, properly controlled rate of flow and diffusion of air being introduced into the room. Their performance is guaranteed. _ Barber-Colman offers you years of combined experience in both air distribution Eroducta and automatic controls and will help you develop the correct relationship Btween room temperature, velocity of air being introduced to the room, and tem perature of moving air in relationship to average air temperature in the room to provide expected human comfort conditions. . (See Barber-Colman page in Controls and Instruments Section.} Complete descriptive literature and selection data available upon request. Grilles & Registers Ceiling Diffusers High Velocity Units High velocity air distribution, pioneered by Barber-Colman, requires technically designed units which will reduce the hign velocity air to conventional velocities and correctly distribute it to the occu pancy zones at minimum noise levels. Barber-Colman offers a complete line of single- and double-duct control equip ment including constant volume control. Model MA sidewall diffuser . (has removable core) Venturi-flo ceiling diffusers Venturi-flo ceiling diffusers feature quiet operation, rigid construction, wide ranee of sizes, efficient diffusion, adjustable deflection volume control, and attractive appearance. They are available for sup ply and return service in both recessed and flush mounting styles, as well as in combination with lighting units. A com plete line of accessories includes volume controls, dampers, and Deflectrols. Barber-Colman high velocity control unit with Venturi-flo diffuser Uni-Flo square and rectangular diffusers with perforated diffuser plate Model FA sidewall diffuser (has removable core) .Model ST continuous line diffusing grille for under-window and sidewall installations. . Uni-Flo grilles and registers-provide rapid diffusion, a high rate of aspiration with resultant high air entrainment ratio, low pressure drop, low noise level, simple adjustment in the air pattern, and a pleasing appearance. A variety of frame styles is available to meet side wall, panel, or exposed duct installation requirements. The removable core fea ture makes it unnecessary to break the paint or plaster seal for cleaning or decorating purposes: Barber-Colman also manufactures a complete line of return, exhaust, and transfer grilles, including the Sight- Tite core for use in doors to provide adequate ventilation without unsightly "see-througb." Accessories Barber-Colman accessories include oppoeed-blade volume controls--Voladjusters, for remote manual adjustment of air volume--Airturns and Defiectrols, for efficient ffow of air around turns and into take-offs. Square and rectangular ceiling diffusers' are available with attractively designed faceplates, both recessed and surface type. Air pattern modification and vol ume control are provided without alter ing the outwaro appearance of the diffuse/s. Uni-Flo square and rectangular diffusers with louver face design ' Uni-Flo double-duct constant volume control The new Uni-Flo double-duct control unit with self-contained constant vol ume control simplifies stabilization of high velocity systems. It mixes hot and cold air ana reduces it to conventional velocity at minimum noise levels. It is self-operated, requiring no power source or motor operator. Cfm delivery and air mixture temperatures are held * within very close limits. Square and rectangular diffusers are abo available with a louver face design to meet specific architectural require ments. These are available with a variety of- vane assemblies to provide 4-way, 3-way, 2-way, or 1-way air patterns. PARAFLO combination air distribu tion and lighting unit This new troffer provides precision-engi neered air diffusion and high comfort illumination in a single attractive unit. Adjustment can be made from below. Air distribution assembly by BarberColman, lighting by Day-Brite Lighting, Inc. Model SCR constant volume regulator The Model SCR constant volume regu lator illustrated above is applicable any . where in a duct system where there are changes in static pressure. No motor operator or other power source is re quired. It provides extremely accurate constant volume control, reducing high velocities to conventional velocities for branch ducts. '  248 Air System Equipment ' ****,,,'WI CARNES CORPORATION VERONA. WISCONSIN Roof and Sidewall Ventilators--Air Diffusers--Registers and Grilles--Baseboard ONE OF THE MOST COMPLETE LINES OF VENTILATORS Hie Carnes line of ventilators includes a wide range of models and a complete selection of sizes and capacities--to fulfill every requirement. Features in- _ elude--quick, easy installation; aluminum housings and curb bases; heavy duty sealed ball bearing motors, installed out of air stream; motors and fan assemblies mounted on high quality isolators, and guaranteed performance. MODEL D1 Extremely low silhouette, especially designed for low parapet buildings. Hra a backwardly inclined, non overloading fan wheel which is direct drive. Housing is heavy gage, corrosion resistant aluminum. Available in a wide range of sizes and capacities. MODEL AX Heavy gage aluminum housing and aluminum, non sparking propeller fan direct motor drive with motor, and fan assembly mounted on resilient mounts to eliminate vibration and noise. Square curb base is standard and is furnished attached when ordered with the ventilator. Several sizes in a wide range of -ca pacities. MODEL BE Low contour for low parapet buildings. Housing is heavy gage, corrosion resistant aluminum. Backwardly-inclined fan wheels, statically and dynamically balanced to provide years of smooth, quiet operation. Large selection of sizes and capacities. MODEL WD Modern streamlined, centrifugal side-wall exhauster. Quickly and easily installed. Can be used with duct work, or as a straight exhaust. Each motor and fan unit is mounted on full-floating rubber vibration isolators to reduce vibration and noise to an absolute minimum. Available in capacities from 120 cfm to 2295 cfm. .Register*, Crfll--, Air ' DlftBHn, Bsschssrd 249 CARNES CORPORATION VERONA. WISCONSIN '****,, Air Diffusers--Registers and Grilles--Roof and Sidewall Ventilators--Baseboard AIR DIFFUSERS MODEL EJ is a completely adjustable diffuser for an infinite number of air patterns. Pattern adjustment is easily made by turning center cone. Ideal for installa tion where cooling, heating or ventilating uses the same duct. MODEL K available in one-way, two-way, three way and four-way blow in square or rectangular models--for surface or recessed installations. Corner air scoops for an even 360 deg pattern. Inner vane removable for easy installation. MODEL EH is half-round diffuser--adjustable for use on ceiling or sidewall. Can be set for either throw at the factory, or easily changed after installation.. MODEL RC AND RGD Convertible Diffuser for heating and cooling. Simply adjusted without tools or disassembly for a two-way, three-way or four-way air distribution pattern.. Available with opposed blade damper as an integral part of unit. REGISTERS and GRILLES MODEL 100 Single Deflection Supply Register with opposed blade damper provides air deflection in two directions and positive volume control. Face bars individually adjustable. 18 gage steel frames. Also available with vertical front bars. 26 standard sizes. MODEL 250 Double Deflection Supply Grille. Avail able with horizontal or vertical front bars. Adjustable rear blades. 18 gage steel frames -rounded edges-- sponge rubber gaskets. In 26 standard sizes. A complete line of registers and grilles available-- write for catalog. ( BASEBOARDS For continuous, even air diffusion, Cames-Brandes is designed to meet the needs of architects and engi neers for exacting requirements. There are standard models for all residential and commercial applications --and a complete selection of varied types. Write for Catalog No. C-B108  250 Air System Equipment HART & COOLEY MANUFACTURING CO., HOLLAND, MICHIGAN Air Conditioning Registers, Grilles & Diffusers--Warm Air Registers--Damper Regulators--Furnace Regulators--Pulleys--Chain No. 74 DESIGN ECONOMY TYPE AIR CONDITIONING REGISTER Flexible-fin face permits any up or down deflection of air-flow. Positive valve with volume control for accurately balancing system. Gasket prevents streaking. Sidewall and Baseboard Registers ia sixes 8x4 through 14 x 8. Grilles 8x4 through 30 x 8. No. 821 DESIGN COMMERCIAL-RESIDENTIAL A.C. REGISTER Multiple deflection provided by parallel action louvers, ad justable to any. upward angle and.downward to 15 deg, and pivoted face bars. Vertical or horizontal louvers and facp bars, snap-in valve positioning handle removable to prevent tamper ing with setting, shallow depth (1% in. - valve open). Face bars pivoted at front to leave appearance of face uniform re gardless of position. No. 831, not shown, has vertical louvers, horizontal face bars. Many standard sixes. Costs less than TRIPL-AIRE line. Ideal for year around air conditioning, par ticularly where low sidewall registers are presently installed. No. 76 DESIGN IDEAL REGISTER FOR SHALLOW OR HORIZONTAL DUCTS Multi-shutter valve (depth in. from wall) and flexible-fin face provide for all deflections desired. Any up or down de flection can be maintained with adjusting screw. Sealed to pre vent streaking. Sidewall and Baseboard type Registers in sixes 6x4 through 30 x 8. TRIPL-AIRE SIDEWALL REGISTERS EXCELLENT FOR COMMERCIAL TYPE INSTALLATIONS Provide any deflection or combination of deflections desired. Opposed louvers afford absolute volume control. 26 standard sixes up to 36 x 12 ... each available in 10 combinations of horizontal and vertical front and secondary face bars, and louvers. All key adjusted from front. ' No. 88 DESIGN SHALLOW DUCTS, LARGE INSTALLATIONS similar to No. 76 except that face bars are adjustable in 2Yt in. sections (one moves all in section). Exceptionally good for large installations. Removable handle available to avoid tampering. Sidewall Registers or Grilles 6x4 through 30 x 24. FIXT-AIRE RETURN AIR GRILLES AND REGISTERS Similar in construction and perfect complement to TRXPL- AIRE line. Same louver, but face bars (single bank) are fixed in either horizontal or vertical position. Grilles may be had with horizontal face bars act at 22 degree angle for up or down de flection. ' No. 16 CEILING DlFFUSAIRE IN No. 18 ADAPTER SQUARE Both this diffuser the No. 15 on the opposite page are de signed to take full advantage of pipe sixes thus providing highly efficient cfm delivery at a minimum resistance. Butterfly damper is available with both. Adjustable from below it allows thorough balancing at the diffuser face. The No. IS ADAPTER SQUARE, for use with either No. 15 or No. 16 diffuser, harmonises nicely ' with acoustical ceilings solving the "round or square" problem with just one diffuser. Gasket prevents streaking. Designed for cooling as well as heating. 5 axes. GAS VENT PIPE AND FTTONCS The H<tC line of Type B gas vent pipe and fittings is com plete. Provides everything necessary for venting gas water heaters and all types of gas-fired heating equipment. mad CriUc Hart & Cooley W/g. Co. No. 401 DlFFUSAIRE--For Perimeter Heating or Cooling. Installed above the baseboard on outside walls, provides an excellent means of blanketing outside wall and window areas with a curtain of warm or cool air. This diffuser disperses air in full 180 degrees spread upward in addition to directing a small portion downward over floor. Adjustable stop on handle permits balancing system at the face. Sixes: 10 x 6, 12 x 6, 14 x 6. No. 405 DlFFUSAIRE--For Perimeter Installation*. Particularly good for use in established homes. Out-of-wall Baseboard type. No stackhead required. Provides same air ~ pattern as our No. 401 Sidewall DlFFUSAIRE. No. 411 DlFFUSAIRE--For Perimeter Heating or Cooling. Floor type. Counteracts downdrafts from windows and cold walla. Opposed louver valves and set-screw adjustment permits accurate volume control for easy balancing of system. Design of louver blades provides even spread of air in fan shaped pattern with minimum resistance. Sizes 2Vi x 10,12, 14; 4 x 10, 12, 14; 6 x 10, 12, 14. No. 46 DlFFUSAIRE--For Perimeter Systems. Continuous baseboard type. Furnished in 2 ft and 4 ft unite for installations of any length desired. Airfoil valve assures mini mum resistance.- This diffuser maintains air pattern regardless of volume, permits balancing system at diffuser face. Flexo- flarige, furnished at no extra cost, provides a tight, quick connection between diffuser and boot. Matching RETURN AIR INTAKE is No. 47. . ._ No. IS CEILING DlFFUSAIRE This diffuser and its companion diffuser, No. 16, shown opposite, provide full 360 deg, draftless air distribution. The difference in the two is this: The rings of the No. 15 are flush, while in the No. 16 the rings step down at a 10 deg angle. Dependable for residential and small commercial installations. 5 popular sizes. ' 251 i  252 Air System Equipment Hendrick Manufacturing Company 48 Oundaff Street, Carbondale, Pa. Sales offices in principal cities--consult telephone directories Hendrick Bulators; Hendrick Perforated Metal Grilles; Hendrick Mitco Open Steel Flooring. Armorgrids, Shur-Site Treads HENDRICK BULATOR.... THE DUAL-UNIT COMBINATION A Deflecting Vane Grille + An Ornamental Grille Now you can secure in a single installation all the advantages of an adjustable vane grille--to direct air flow--and an ornamental grille--to harmonize with the decorative scheme--by specifying the new dual unit Hendrick BULATOR*. It is a practicable com bination that meets both the engineer's specifications for air throw.and spread, and the decorative require ments of the architect. In this dual-unit, the deflecting vanes are not no ticeable, although they are mounted just behind the ornamental grille. The vanes are adjustable so that the air flow can be deflected to right or left, up or down, or in a combination of both directions. For the imposed ornamental grille section of the dual-unit Buiator, Hendrick offers a wide selection of attractive designs, with the essential open area. Tested at Case Institute To determine the efficiency of the dual-unit, tests were made at the Case Institute of Technology, Cleve land, under the direction of- Professor G. L. Tuve, as a result of which, "it was found that at a given air vol ume, the presence or absence of the `Mosaic' (design) grille made very little differences on either the air stream pattern or the throw." . A copy of the detailed report on these tests will be mailed on request. Bedster* Md crie* Hendrick Manufacturing Company HENDRICK PERFORATED METAL GRILLES Hendrick decorative grilles are furnished in over a hundred patterns, and in a wide variety of overall di mensions, bar sues, and number and size of perfora tions. 253 ArgUn--63 percent Open Area Many exclusive Hendrick designs, originally pro duced to meet an architect's specifications for some particular project, are now available as standard num bers, and facilities for making special designs to speci fications make the Hendrick service even more com plete. The wide range of patterns permits the choice of a grille that will harmonize with any style of archi tectural design or period construction. Grilles are fabricated in heavy-gage aluminum, bronze, copper, Monel, steel, stainless steel, and other commercially rolled metals. With ample open areas and accurate sizes, Hendrick grilles are characterized by clean-cut perforations, fine finish, and freedom.from' burrs and other imperfections. They are easy to install, and always lie flat because of a special flattening operation in their manufacture. If among the Hendrick special and standard designs you do not find something which meets your require ments, we shall be glad to submit suggestions or to work with you in the development of a special design. La Crosse--55 percent Open Area lyi r.v Ar.i Mn bV'j A Ar.v A A AV A it l'j Vn ArrA.-vivAl'j A A lr.'vj l'j rmi l'j l'j Ar.v l'j A A lrA.'vj rArA..vv l'j kaj r.i r.v r.v l'jr.i Vl'j lr'.jv rAr..vi V l'j lr.'vjrA.v r.v AV A V r.v rA.v o r.i r.v rA.v r.v V V rA.v 2" Link--52 percent Open Area Air Conditioning Grilles and Registers Hendrick air conditioning grilles and registers for di rected air flow are made in various meshes, the standard having Vt in. or % in. opening between face bars. Ail types furnished with either horizontal or vertical di rectional bars either permanently set or so that they may be individually adjusted on the job to direct air flow to any desired degree. Grille and register faces are made regularly of steel with prime coat finish. They can be furnished in a lacquered finish to match any color sample. 1. i taken with deflecting vanes leS3 than an inch ind grille, shows that vanes are sot noticeable Vertical deflecting vanes, showing how the vanes may be set to produce any desired air stream pattern . How to specify or order Hendrick Bulators In specifying or requesting quotations on the Hendrick dual-unit Buiator, the following information is re quired: 1. The name or description of the desired ornamental grille, as given in the Hendrick Grilles cat&log. 2. The metal, gage and . finish of the orna mental grille, that is required. * Beauty 3. The dimensions of the air duct opening. 4. The type of deflection desired in the de flecting vane section; whether right and left, up and down, or a combination of both. Ventilator. M-No. 2--57 percent Open Area M-No. 9--67 percent Open Area Va" Diamond--60 percent Open Area lfi" Shell--72 percent Open Area  254 Air System Equipment Charles Demuth & Sons, Inc. Mineola, N. Y. Demuth Draftless Air Distributors Representatives in Principal Cities New-Type (D-3) available now Type (s) Type (F) Type (M) Designed and Patented by Demuth Illustration showing _ curved equalizing deflecting air vanes and method of installation The DEMUTH DRAFTLESS AIR DISTRIBUTOR Consists of a series of curved vanes, mounted on a deflecting cone, to insure 360 deg distribution without . the aid of secondary equalizing devices. A second hollow deflecting cone is arranged at a tangent to the primary cone, forming an injection nozzle. The curved vanes discharge the supply air in fcurbu. lent streams, mixing room air with conditioned air, thereby providing constant air motion, uniform tem perature and draftless distribution throughout the room. Secondary air currents, which are created by the turbulence of the discharge air, are drawn into the diffuser by the bottom or secondary cone, mixed with the supply air, resulting in positive aspiration. Type (SQ) square and rectangular Air Diffusers are made to any size with removable core assembly. Air distribution is from one, two, three or four sides of the diffuser. Made to any air pattern. . Accessories Combined lighting is available with the circular type. Volume and Splitter Dampers are available for all types. Type (SW) Type (SQ) Air System Equipment ud cmut The Independent Register Company 3747 East 93rd Street * Cleveland 5, Ohio ________Independent "Fabrikated"* Registers and Grilles 255 The valves swing from their edges and, when closed, lie flat against the flanges on the back of register face. With valves closed, register depth is VA inches, except on the side, or end, of the operating lever, which is \y* inches. With valves open the complete depth is 2 inches. If the valve length exceeds 24 inches, face and valves are made in tandem and valves are operated by two or more levers, as may be required. INDEPENDENT ADJUSTABLE BAR DOUBLE CORE REGISTERS cataiog eires. bixes over 12 inches vertical, 1 all four sides beyond wall opening sizes WWiider or narrower Jjms can be furnished at moderate additiona*l cost. Tbeae registers are available in 114 standard sires to fit practirally any opening from 8 in. * 6 in. to 48 in. x 48 in. Special sizes furnished on order. These units, No. 27, have adjustable vertical front bars and adjustable horizontal rear bars. Opposed blade, volume control dampers are key operated. Style No. 28 has adjustable hori zontal front bars and adjustable vertical rear bars. Made to fit wall openings from 8 in. x 4 in, up to 48 in. x 24 in. in 90 different sizes. "WT" WALL FRAME No. 311D-WG--Bars Faced Down The:* grilles are designed for commercial installations. Style No. 311-D-wG illustrated has grille bars set permanently at approximately 35 deg down. Other models available have grille bars set for straight flow. ' "FaJbrikated" Floor Registers ' for Perimeter Heating Can be separately installed before plastering. Duct openings must be made approximately Vi in. oversize. Frames must be fitted and attached to grilles or registers at our factory. Made in sizes to accommodate sizes of No. 27 and No. 28 Double Core Registers. rAKJinuftS No. 60A Faces are famous "Fabrikated" construction, excelling in rigidopen .area and fine appearance. Adjusting screw permits directed air flow toward outside wall when valves are set into pr^er position. Sizes comply with code requirements of " , ,, " ACA. Fabnkated floor faces for return air are also available. No. 1312R No. 1312R No. 1312C No 1312RR The gnlle bars are V-shaped; it is impossible to see through the gnlle from any viewpoint 6  256 Air System Equipment iuw. nd crfu-- KRUEGER AIR CONDITIONING CORP. 19 East RILLITO KRUEGER TUCSON, ARIZONA SUPPLY REGISTERS AND GRILLES Series 880 OBJ). Registers combine double deflection grilles and opposed blade damper units to give complete control of air in both planes plus equal distribution over entire face of register. Volume control valve is easily adjusted from face. MULTI-SHUTTER REGISTERS Series 800 Multi-Shutter Registers pro vide adjustable front fins for any desired deflection and rear louvers are gang oper ated. Models have either vertical or horizontal streamlined fins % in. deep set on % in. centers. RETURN AIR GRILLES PERIMETER REGISTERS: Series 900 Baseboard Registers offer easy installa tion in both new and old construction. Register housing can be installed at time of "rough in." Grille facing and damper installed later. Features rubber- tipped lever operated damper and attrac tive appearance. 18, 24, 30 in. lengths. ROUND CEILING DIFFUSER has 360 deg air diffusion pattern. Friction controlled butterfly damper has full 90 deg control operated from center shaft. Step-down design does not require increase in duct size at neck for installa tion. Five sizes from 6 in. to 14 in. diam. A fine low-cost register for combination beating and cooling. Vertical fins diffuse air in two directions- Adjustable multi louver has positive shut-off control. Front fins are spaced H in. for greater free area. Series 80 Return Air Grilles, matching units for air supply registers, combine rugged construction and fine appearance.. Fins spaced on % in. centers are set at 35 deg angles. Available in horizontal and vertical models. DAMPERS AND ACCESS DOORS AIR & VOLUME CONTROLS designed to balance air volume and distribute flow equally over grille face. Curved blades, adjustable from full open to full closed, stabilize pressure ana mini mize friction loss. EX-8 Extractors avail able in 26 standard sizes. MIXING DAMPERS (left) Manufactured in Opposed-Blade, Multi-Louver, Face And By-pass, and Right Anjgle designs. Construction of heavy channel frame rigidly welded with brass pivots. Louver bearings are bronze sleeve type. Built for manual or motor operation. FIRE DAMPERS (center) Manufactured to N.B.F.U. specifications- Construction of welded heavy channel with 12.gauge damper blades pivoted off-center to assure positive closing. Bronze sleeve bearings. Fusible Link furnished at 165 deg or speci fied temperature- Glosiog spring is standard part of damper assembly. ACCESS DOORS (right) Manufactured to any desired size and offset edge or flat frame types- Construction of 16 or 18 gauge cold rolled. Continuous type hinge lo cated on long dimension. Metal screw locks door to frame. Special locking devices available. . NON-VISION DOOR GRILLES pro vide constant passage of air with com- Elete obstruction to vision. "V" shaped ns are spaced on H in. centers for greater free area. Series 600 Non-Vision Grilles are available in three styles, 88 sizes. Also available are light-tight Double "V" Grilles. PLASTER FRAMES provide a neater installation for registers and grilles by protecting plastered or panelled walls. FILTER FRAMES provide easy access to filter pads installed in Frame directly behind return air grilles. Air System Equipment ouu ud cnn*. THE PYLE-NATIONAL COMPANY 257 Multi-Vent Division 1363-78 North Kostner Avenue Chicago 31, Illinois 8 Sales Engineers and Agents In Principal Cities U. S. and Canada MULTI-VENT AIR DIFFUSERS Low velocity, draft free air diffusere that permit complete concealment in ceiling and complete freedom in placement re gardless of the proximity of partitions (movable or stationary). Multi-Vent low velocity, air diffusing panels are available in In addition, Multi-Vent panels can be custom built in any shape or size, material or finish, to suit unusual needs. Your inquiries for additional information on the selection and various models, styles and sizes to suit all types of ceiling con struction. The more popular, standard types are briefly de scribed below. application of Multi-Vent panels will be given every considera tion by our experienced engineering staff. Our extensive labora tory testing facilities are also at your disposal. TYPE MVM MODULAR MULTI-VENT PANELS For acoustical metal pan ceilings. For radiant pan ceilings. For plaster and acoustical tile .ceilings. For exposed duct applications. BASIC MULTI-VENT COMPONENTS Modular Multi-Vent diffusers consist of four basic parts: Duct collar, tubing, panel, and perforated distribution plate. (The distribution plate is not required when standard perforated acoustical ceil ing pans are used.) Modular Multi-Vent Panel in Stand ard Acoustical Metal Pan Ceiling. Linear Multi-Vent Panels in Acousti-Line Ceiling. TYPE MVL MULTI-VENT PANELS ESPE CIALLY SIZED AND ADAPTED FOR USE IN THE FOLLOWING CEILINGS: Acousti-Line Mineral Tile Ceilings ' Acousti-Luminous -Ceilings Alumi-Coustic Ceilings Simplex Ceilings Wakefield Ceilings Multi-Vent Troffer in acousti cal Mineral Tile Ceiling- TYPE MVB MULTI-VENT TROFFER Patent Number 134&8S4 ud Combination Air Diffuser and Troffer Light. Air diffuser by the Pyle-National Com pany, lighting by Benjamin Electric Manufacturing Company. For use in any type of drop ceiling. Takes flexible hose and duct collar. Type MVM Multi-Vent Modular Panel MVL Multi-Vent Linear Panel MVB Multi-Vent Troffer Valve Unitary Multi-Vent panel in acoustical metal pan ceiling. TYPE MVAC TYPE MVAR UNITARY MULTI-VENT PANELS* For acoustical metal pan ceilings. For plaster and acoustical tile ceilings. For exposed duct applications. *For special applications available with built-in secondary filters; built-in germi cidal lamps; built-in radiant beating, radiant cooling coils. 1-Control Plate and Frame. 2-Pressure Displacement Air Valve. 3-Perforated Plate Ox* mtabed wfaea taadtfd Kouliul ctaQnj oaed).  258 Air System Equipment B Engineered Products for Residential, Com mercial and Institu tional Air Condition ing, Heating, Venti- NEW BRITAIN, CONNECTICUT HIGH PRESSURE AIR DISTRIBUTION UNITS TYPE MPW A complete line of equipment de signed to meet the growing de mand for high pressure installations in multi-story office buildings, schools, hospitals, hotels and in stitutions. TYPE MPW Medium Pressure Periphery Wall Mixing Plenum Unit for individual room control on beating or cooling cycle, or zone control. Handles static pressure in system up to 3.5 in. w.g. TYPE MP Medium Pressure Sub-Central Station Unit for d tribution of air to one or more diffusers by means rigid or flexible ductwork. Handles static pressure system up to 3.5 in. w.g. TYPE MPD Medium Pressure Ceiling Diffuser Double Duct Mix ing Plenum Unit for individual unit or tone control. Single duct units also available. Handles static pressure in system up to 3.5 in. w.g. TYPE PRV Pressure Reducing Valve for use in medium pressure systems, temperature muring units and sound attenua tion boxes. Manual or automatic operation. I B 'a ? a Critic* . Tuttle & Boiley AEROFUSE CEILING DIFFUSERS 259 ! A wide selection of diffuser types and sizes, styled and engineered to meet the most rigid requirements of appearance and performance at the point of air delivery. - TRI-FLEX SUPPLY AIR GRILLES AND REGISTERS Available as single and double de flection grilles; single and double deflection registers with opposed blade dampers. Blades are regu lated by means of a key operator and may be set in any position from fully open to fully closed. Face bars are individually ad justable. Stocked in 26 standard f ? ji 8x4 10 x 4 10x6 12x4 12 x 5 12x6 26 STANDARD SIZES 14x4 14 x 5 14x6 16x5 16 x6 20x5 20 x 6 20 x 8 24 x 5 24 x 6 24 x 8 24 x 10 24 x 12 30 x 6 30 x 8 30 x 10 30x12 36 x 8 36x10 36 x 12 AEROVANE RETURN AIR GRILLES AND REGISTERS Aerovane grilles are available with horizontal or vertical bars. Aerovane registers are furnished with the same opposed blade damper units as supplied with TriFlex registers. Stocked in 20 standard sizes. . . 20 STANDARD SIZES 10 x 6 10 x 8 12 x 6 12 x 8 12 x 12 18 x 6 18 x 12 18 x 18 24 x 12 24 x 18 24 x 24 30x12 30x18 30x24 38 x 18 36 x24 36x30 48x24 48x30 48x36 X *260 Air System Equipment UNITED STATES REGISTER COMPANY Battle Creek, Michigan, U.S.A. AIR CONDITIONING REGISTERS--GRILLES--DIFFUSERS--EXHAUST and BACK PRESSURE DAMPERS--ACCESSORIES No. 153 U S. Air Conditioning Single Valve Register, Lever-Operated. in. Bar Spacing 22 deg. affords Non-Vision. With Rubber Sealing Gaskets. No. 190 U.S. Multi-Flex Register, Verti cal Streamlined Front Grille Ban, Horizontal Rear Bars, Individually Adjustable, Screwdriver Operated Op posed Rear Valves. No. 256 U.S. Air Conditioning MultipleValve Register, Lever-Operated. \i deg. Bar Spacing 22 deg Right and 22 deg Left gives 4-Way Diffusion and Non Vision. No. 191 U.S. Multi-Flex Register, Hori zontal Streamlined Front Grille Bars, Vertical Rear Bars Individually Adjust able. Screwdriver Operated Opposed Rear Valves. No. 249 U.S. Air Conditioning Multiple- Valve Register, Lever-Operated Valves. Vertical Grille Bars Completely Adjust able to 45 deg Right and Left Flow and Two-Way Flow. t No. 192-L Multi-Flex Register, Vertical Streamlined Grille Bara Individually Adjustable. Lever-Operated Parallel Multiple Valves. No. 192 Same, but Screwdriver Operated Opposed Valves. No. 153-VVL U.S. Air Conditioning Multiple-Valve Register. Horizontal yi in. Bar Design. Two-Group Lever Operated, Vertical Rear Valves which afford Right and Left Flow or Two-Way Flow. ' No. 201 Non-Flex Register, Return Air-- Fixed Horizontal Bars. No. 200--Fixed Vertical Bars. For Multi-Flex Grilles and Non-Flex Return Air Fixed Bar Registers and Grilles, see Complete Catalog. . UNITED STATES REGISTER COMPANY-A-C REGISTERS--GRILLES--DIFFUSERS-- _________________________________ DAMPERS--ACCESSORIES No. 1500 Round Ceiling Diffuser Cross Section fine lor bound Outlets--also Residential No. 105 U.S. DIFFUSER A-C REGIS TER. ISO deg Perimeter Diffusion Three Sizes No. 1800 Round Ceiling Damper, Re movable Knob Control . No. 2500 SQUARE STEP-DOWN CEIL ING DIFFUSER. Also made in No. 2501 FLUSH-TYPE No. 2540--Cross-Section No. 410 DIFFUSER FLOOR REGIS TER for Perimeter Svstems- Made in Nine Sizes No. 400 U.S. Trussteel Floor Register, Grid-Bar Face 2 x ! in. O.C. spacing of Bars. No. 2800 Square Ceiling Damper, Re movable Knob Cootrol No. 600 US. SANI-STEEL REGISTER, lHf io- Square Meab in. Bars. Valve and body construction same as No. 400Lever Operation No. 600. Key Lock Operation specify No. 625. Key-Opera tion specify No. 620. Pole-Operation specify No. 650.  262 Air System Equipment * YOUNG REGULATOR COMPANY 20910 MILES AVENUE, CLEVELAND 28, OHIO SURFACE-CONCEALED - SPUTTER - SQUEEZE - REMOTE CONTROL DAMPER 5 REGULATORS Young Regulator Company offers & complete line of manmdiy controlled damper regulators for every type of heating, venti lating and air conditioning installation in office buildings, factories, hospitals, ships, schools, churches and residences. Young Regulators are used by many leading companies is nearly every industry and are specified by leading architects and engineers. No. 1 Surface Mounted, Direct Connection Regu lator The original Young Damper Regulator, of which thousands have given satisfactory service for years, has been modernised . and streamlined. It is used to regulate a damper, controlling the air flow through a duct. It is readily set and locked into posi tion by a key. No. 700CP Remote Control Damper Regulator This regulator is for manual operation of dampers and registers to give individual room temperature by remote control- With No. 704 Corner Pulleys, Remote Control Regulators operate Young Dampers at a distance of 250 feet or more. Two registers or dampers can be operated by a single unit. No. 301 Concealed Damper Regulator- This regulator is installed in ceilings or walls. The boa is em bedded in the finished ceiling or wall material so that the flange is flush with the finished surface. Cover plate* is 3}i in. in diameter and covers the joint between the box and plaster. Operation is by key or a socket wrench that fits the end of the damper rod. No. 315 Adjustable Cover Concealed Regulator This regulator is for use in acoustical ceilings. It is similar to the No. 301 Concealed Type, except the cover plate is ad justable for height by screwing down the cover plate in order to meet the various thicknesses of acoustical or plastered ceil ings. The adjustment or locking of the regulator is by a key or socket wrench. No. 330 Floor Line Adjustable Cover Regulator This new Young Regulator is set flush with the floor in a branch duct ppr a grille and is used for perimeter heating and air No. 900 Series Air-Split Damper Regulators conditioning installations. It gives accurate volume control of No. 900, illustrated above, is one of six Young Regulators used for operating splitter or squeeze dampers. The operating heads may be placed in any accessible location. Operation is by crank. air in branch ducts and makes possible the use of grilles in place of expensive registers and eliminates the necessity of separate ducts running to the heating and air conditioning room. 30F FOR COMPUTE DETAILS SEE OUR CATALOG IN SWEET'S ARCHITECTURAL FILE ^ Crfl'.M. YOUNG REGULATOR COMPANY 20910 MILES AVENUE, CLEVELAND 28, OHIO DAMPERS - REGISTERS - GRILLES Young Regulator Company offers a complete line of dampers, registers and grilles for air conditioning and heating installations. 263 No. 830 Opposed Blade Damper No. 830 Opposed Blade Damper distributes the air evenly over the entire face of the grille. It is easy to install in the duct be . hind the grille and is operated by a Remote Control Regulator placed in a convenient location. Tubing to the Remote Control Regulator is attached to the duct by a Compression Fitting. No. 830 Damper is furnished as part of No. 840 Series Air Con ditioning Register or separately. . No. 831 is the same as No. 830, but without the.Remote Control attachment. Operation is by key. * No. 817A Volume Control Damper No. 817A is an Opposed Blade Damper similar to No. 830. It is installed in a branch duct to control the volume of air mid is operated from a suspended ceiling by No- 301 Regulator. The unit is operated by a crank, and can be locked in position by key.- No. 890 Air Extractor No. 890 Air Extractor has blades that operate in unison and are controlled by a key through the grille. The adjustable extractor scoops the required amount of air from the main duct into the branch duct. No. 840 Series Adjustable Bar Registers Young No. 840 Series Registers combine the various No. 800 Series Young Grilles and a vertically Opposed Blade Damper. These registers give individual room control when operated by No. 700 Remote Control. No. 841 Series is similar to No. 840, but without Remote Con trol attachment. Operation is by key. No. 875 Series, No Sight, No Light Grilles These grilles are for dark room installations or where light must be excluded but where ventilation is required. Finish is of non secular black, assuring no light reflection. No. 882 Perimeter Baseboard Diffuser This Young Diffuser provides proper distribution of warm or cool air to all parts of the room and is engineered to induce continuous aspiration of air throughout the room. Using con nectors furnished, the lengths can be combined to furnish con tinuous runs to fit any length of wall. - No. 800 Series Air Conditioning Grilles Grille bars are made of extruded aluminum secured in a frame and dividing mullioas. They must be adjusted with a hand tool. No. 800-VH has double banks of blades, one vertical, the other horizontal, both banks adjustable. No. 845 Series Return Mr Grilles These grilles, for intake, have been designed to match the No. 800 Series for supply. FOR COMPLETE DETAILS SEE OUR CATALOG IN SWEET'S ARCHITECTURAL FILE  264 Air System Equipment UNIVERSAL DIFFUSER CORP 38 Marbledale Road, Tuckahoe, N. V. AIR DIFFUSERS - REGISTERS * GRILLES ADJUSTABLE DIFFUSERS Provide an infinitely variable means of controlling air volume. Control mechanism moves all blades up or down simultaneously. TYPE QP--A circular 4-cone adjustable pattern diffuser. Rotating lower blade moves core up or down, changing air delivery pattern from horizontal through any angle to vertically down; forcooling, ventilating or beating. TYPE R--Circular constant pattern with volume control; air travels parallel to ceiling; for cooling purposes. TYPE ' V--Circular variable diffusion pattern from horizontal to vertical with simple adjustment; for heating, ventilat ing, cooling or for high ceilings.. NON-ADJUSTABLE Made with fixed blades; volume control is obtained by the use of face operated volume dampers. TYPE B--Circular, non-adjustable dif fuser for cooling and heating; attrac tively styled for small commercial, in dustrial and residential ceiling applica tions. TYPE H--Square diffusers with round necks, made in 3 models: HAR--constant pattern with control of air volume through cone adjustment. HAV--variable pattern by moving cones up and down. TYPE CH--Circular supply and return H-F--fixed pattern with 4 different face diffuser with both "R" and "V1' char acteristics. Eliminates return grilles. patterns. TYPE MP--Rectangular and square, multi-pattern diffuser: l-way, 2-way. 3-way and 4-way; made in 18 styles ana ' 64 sizes for any type and shape of inte rior. Air diffusion pattern is determined by the style, without use of baffles. LINE-AIR--Long slot diffuser of any desired length for side wall and ceiling: Counter-current vanes provide means to deliver air at 90 to wall face without the use of auxiliary straightening vanes. UNIVERSAL GRILLES AND REGISTERS 1--Double Deflection Grilles 2--Double Deflection Registers 3--Opposed Blade Dampers 4--Return Grilles and Registers 5--Door and Partition Grilles 6--Air Extractors 7--"Grilline" Long Slot Grilles 8--Volume Controllers 9--Plaster Frames Air System Equipment WATERLOOREGISTER COMPA^,lNC. "Since 1902" P. O. Box 72 Waterloo, Iowa WATERLOO offers a complete line of Air Diffusion Equipment designed particularly for commercial and industrial heating, ventilating and air conditioning 2V Supply Grille Twu sets of extruded aluminum louvers, each indi vidually adjustable for four-way deflection at degree desired. . 3H Return Air Grille . Fixed fins at 45 degrees of 0 degree deflection, in heavy gage frame, strengthened with adequately spaced support bars. 1VMH Supply Register One set of adjustable louvers for. easy control of air, right or left, with multi-shutter damper, horizontal blades. Ideally suited for residential installations be cause of narrow stack depth. DV Door Ventilator Inverted V-Shaped fins are permanently affixed to channel frame providing rigidity and complete sight proofing. Provides 72 percent free area. Available flange both sides, one side or channel frame only. OB Damper Opposed Blade Volume Controller may be purchased as a separate unit or can be incorporated as integral part of all Waterloo grilles. DUCTROL Air Volume Extractor ' ' Volume controller and extractor adjusts from full open to full closed, to provide even distribution to entire grille surface. Completely assembled at the factory-- ready to install on job. This product of all extruded aluminum construction features solid in. face bars on Y in- spacing. Available with or without dampers. Ideally suited for wall, sill or floor applications. The complete Waterloo catalog is available upon request containing illustrations and engineering data on all products.  266 Air System Equipment 'SZdZUf** DURO DYNE Corporation Route 110, Farmingdale, New York Manufacturers of Specialties for the Sheet Metal, Heating, Air-Conditioning and Ventilating Fields DURO-BLADE KIT Pat. No. J.86W74 Multi-Blade Louver Damper Hardware The Neva-Bind Duro-Blade Kit (multi-blade louver damper hardware) assures absolutely smooth damper operation, despite the fact that little care is required in assembly, with no align ment necessary after assembly. The kit's unique 4-way adjustability automatically com pensates for alight errors in blade dimensions or formation; minnr misplacement of bearing holes, or other poble in accuracies which cause bending stress of connecting rod--the main cause of binding. The Neva-Bind feature allows the rod to remain straight regardless of any of these inaccuracies of damper construction. In addition, a damper made with the Neva-Bmd DuroBlade Kit can be fully closed without the bracket, hitting the duct. The damper can be fully opened without interference from the connecting rod. VANE RAIL* FOR MAKING AIR TURNING VANES The savings in installed costs of air turning vanes run from 50 percent to 70 percent when vanes are assembled with Duro- Dyne Vane-Rail. Vanes are sheared from simple scrap. Tab cutting on vanes is completely eliminated. . Vanes are simply inserted into concaved notches of Vane Rail. To lock assembly, place chisel (supplied with each bundle of Duro Vane Rail) on portion of vane protruding through ... one sharp blow on chisel securely locks vane to rail. P-K* REGULATORS AND QUADRANTS A--UNXLD* DAMPER QUADRANT SET--H in. siae used for dampers up to 20 in.; n in. size for dampers up to 30 in. Provides positive control. Sturdily constructed, easily installed and adjusted. B--HEAVY DUTY QUADRANTS--Regulate larger size dampers up to 60 in. The ball bearing auadrants are fine manually operated heavy duty units. The plain bearing quad rant for larger regulators up to 52 in. has the same rugged con struction except for the bail bearing feature. Size % in. to 1 in. C--JIFFY* REGULATOR SET--Installs more quickly since it does not have to be attached to the duct. D--DIAL DAMPER REGULATION SET--V4 in. size for dampers up to 10 in.; % in. size for dampers up to 20 in. Special construction prevents air leakage and damper rattle. Made of heavy gage steel, cadmium plated. "OPAX"* OPPOSED ACTION DAMPER LINKAGE SET Opposedl action dampers are preferred by engineers to the usual parallel assem.b.ly.beca&uussee turbulence is minimized and c_o__n_t_ro__l _o_f__a_ir__m__o_re linear. "'OPfAX" Linkage Set includes two brackets and pre-ossembled linkage rod which will provide efficient opposed action of damper blades 5 inches and wider. The 4 way self adjustability automatically compensates for. construction inaccuracies to assure smooth bind-free operation. Rugged construction permits use of the "OPAX" Linkage Set for the largest commercial and industrial damper installations. Duro*Dyne's "OPAX" Linage Sets are boxed in complete units with installation instructions supplied. 1 * Trade Mark ScgaUtcf* C*atni TmU Duro-Dyne Corporation FLEXIBLE DUCT CONNECTOR PRODUCTS Coils of Pre-ossembled Metal-to-Fabric-To-Metal for KHmimiting Vibration Travel 267 DURO-DYNE INSULATION ADHESIVE IA-22* DURO-METAL-FAB* ECON-O-FAB* and "JUNIOR"* are pre-assembled rolls of metal and fabric. They eliminate the annoying, expensive, time-consuming job of attaching metal to fabric in the shop. Featuring an unusual "Double-Loc Seam," the metal cannot puli away from the fabric when the finished connector vibrates; nor can the metal cut the fabric. For industrial applications or heavy gage duct work use DUROMETAL-FAB. Consists of 24 or 26 gage galvanized iron at tached to VL Approved Canvas, Asbestos or Neoprened Fibergjas. Dimensions: Metal 4 in.; Fabric 3 in.; Metal 3 in. For residential and lighter gage duct work, use ECON-O-FAB. Iden tical to DURO-METAL-FAB except for lighter gage of metal. For lowest cost residential application, T`JUNIOR" flexible duct connector is available in narrower dimensions: Metal 2 in.. Fabric W* in.. Metal 2 in. All three sizes are packed in 50 ft or 100 ft coils in handy Dispens-o-Flat Cartons. Special DUCT FABRIC* is available where fabric is re quired without metaL Packed in 100 it rolls. Canvas comes in 6 in. and 10 in. widths; asbestos and neoprene 6 in. wider' A specific use adhesive designed for a quick, strong, permsneat bond of insulation to sheet metal. Created for bonding insulation to metal; insulation to in sulation (at joints); sealing joints; "Buttering" insulation edges. Designed for glass-fiber, asbestos, cork insulation, etc. - Tack Time is only 10 seconds. Bond is immediate and posi tive. Long "open time" range permits bond one hour after ap plication of adhesive. Permits rapid coating of duct surfaces and provides positive bond of heavy insulating material" with out auxiliary holding devices. Brake-forming of metal and insulation is posible immedi ately after bonding without separation of insulation from metal. Coverage of Duro-Dyne Adhesive IA-22: Brush Application: 230 + sq ft per gallon Roller Application: 270 + sq ft per gallon Temperature Range: -30 F to 325 +F (Blanket) -30 F to 250 + F (Board) Duro-Dyne Adhesive IA-22 is waterproof, clear in color, solvent in petroleum-naphtha or white gas. Requires no thinning. Packing: 5 gal and 1 gal cans. DURO-DYNE DUCT TAPE* Duro-Dyne Portable Spot Welder "OX" Metal Punch For use in sealing air duct installations and as vapor barrier sealer on insulation. . Two types available--cloth and reinforced fiber. Both have excellent characteristics. High strength, waterproof, tempera ture range. Aluminum color--popular widths available. HIGH VELOCITY DAMPER REGULATOR AND QUADRANT SETS A complete line of damper controls designed specifically to meet the reauirements of increased velocities and pressures found in modem air distribution systems. Damper rattle is virtually eliminated by the positive lock ing device between the damper shaft and . the . regulator or quadrant. A new close tolerance tail piece bushing is used to support the damper in smooth rattle-free operation. Air leakage is overcome by the use of sealing washers clamped into position by locking nuts at control end as well as tail end of damper. Hi-V Dial Regulator Sets are available in two sizes: Va in. for small dampers--HV-145 % in. for larger dampers--HV-195 ' Hi-V Quadrant Sets are available in the % in. rig*: W in. for heavier applications--HV-3S5 More detailed information is available on request * Trade Murk '  268 Air System Equipment S5S*v^J^1*** CDnited sheet metal CO., INC. 540 S- out-h --Drexel A* venue ^C1ol-u----m----1b--usc o9, AOlh,;i/o, Representatives in Principal Cities of United States and Canada Specialists in Low Loss Components For High Velocity Systems Manufacturers of Prefabricated Metal Spiral "Lockseam" Duct, Die-Stamped, Two-Piece "Laminar-Flo' 1 90 deg Elbows, Matched Low Loss Fittings, and Sound Absorbers--For High. Velocity Systems SPIRAL "Lockseam" Duct For High Velocity Systems- Furnished in any lengths up to 20 ft as continuous duct. 12 ft lengths are standard. /"N Cross sec tion show ing 4 ply seam, ex ternal ' formed rib, internal smooth area- REDUCES FRICTION LOSS At 4000 fpm the friction loss averages of spiral duct as compared with, clean, round, galvanised, metal duct having approximately 40 joints per 100 feet are as follows: ftPTRAI, DUCT FRICTION *r ig r . 15% less Specifications of Spiral Lorkstxm Duct . __________ DIAMETER nominal SIZE EXACT WEIGHT LBS. PER l.D. FT. METAL GAGE 9.BSJ 9.033 .833 l.Ott 1.393 1.593 3.029 29 39 te.os ir 33.CI3 7.219 SOUND ABSORBERS Sound absorbers for high velocity sys tems. Eliminate high and low frequency sounds. Two-Piece Die-Stamped "LAMINAR-FLO" 90 deg Elbow Type E 1 Specifications of "Laminar-Flo" 90 deg Elbow, Type E-l ' Available in diameters of 3', 4#, 5', 6 , 7' 8' 20 ga. galvanised steel, continuous weld, longitudinal seams. Available m aluminum and other specified alloyB. Static Pressure Loss of "Laminar-Flo" 90 deg Elbow, Type E-l Inches of water at 0.075 Ib/cu ft Density "Zero Length" Loss. Add to duct friction calculated from intersection of duct centerlines 20 ga. galvanised steel. Continuous weld. Available for every diameter ol spiral duct. Portion of types available ahown below. ` I Air System Equipment rtaou Dnct *a 269 The Wiremold Company Hartford 10, Connecticut FLEXIBLE AIR DUCT Sales representatives in principal cities throughout the United States and Canada FLEXIBILITY MAKES AIR DUCT VERSATILE Wiremold Flexible Air Duct provides an efficient, economical means for conducting hot or cold air, gases, fumes, dust, or air-borne particles at high or low velocity. Com pletely different from any other duct, Wiremold is made by a process that mechani cally locks the fabric and the supporting metal spiral. There is no glue to dry out and fail with age. Its principal advantages are these: makes any bend easily, without feinting ... dampens mechanical vibrations ... saves hours of drafting time, because there is no need to work out exact positioning details on installation layouts-... eliminates the need*for expensive, special elbows ... one man can easily install even the largest site, without needing any special tools ... no air'leakage within recommended oper ating pressures . . minimum friction loss. Wiremold Air Duct is made in many types and sites to meet varying requirements and provide the longest possible service life. Write for full details. FOR AIR CONDITIONING. After three years of development, including over 25,000 hours of accelerated aging tests, Wiremold offers three types of air duct specifically for air conditioning applica tions. Manufacturers of air distribution equipment recommend the use of such connectors on the high pressure side of the attenuation box, as well as for runouts to air distribution units. Because the duct is flexible, diffusers can-easily be relocated to meet the changing needs of tenants. ' 5 major uses in air-conditioning systems FOR VENTILATING... Two types of flexible ducts--one to handle dust and abrasive particles, the other to handle corrosive fumes and gases--are available for industrial exhauBt systems. They can be hooked up to central or portable collection systems without costly duct work, elbows, fittings and connections. - typical exhaust systems On surface grinding machine, duct moves back and forth with grinding wheel, to exhaust with maximum efficiency. Glass dust and particles are removed from glass cutting machine. Height and length of cut are easy to adjust because of flexible duct. 270 Controls and Instruments ALCO VALVE CO. 851 Kingsland Avenue, St. Louis 5, Mo. thermostatic expansion valves ... constant pres sure (AUTOMATIC) EXPANSION VALVES .. . REFRIGERANT DISTRIBUTORS . . . SOLENOID VALVES . . . SUCTION LINE REGULATORS ... FLOODED EVAPORATOR CONTROLS ... RE VERSING VALVES ... LIQUID AND SUCTION LINE STRAINERS. SEE YOUR ALCO WHOLESALER For capacities In excess of those listed, write ns and give specific requirements THE COMPLETE LINE OF REFRIGERANT CONTROLS thermo expansion valves For automatic control of liquid refrigerant on all types of re frigeration and air conditioning systems. Capacities: from fractional tonnage to 200 tons Refrigerant 12 and Freon-22; selective charges. Low temperature valves for --40F to --100F. TYPE 402 with pressure lim iting feature TYPE PO Pilot operated--maintains sensitive control over wide ranges in TYPE TCL With either angle or straight-thru connections TYPETR Multi-Outlet SOLENOID VALVES TYPE SI TYPE S2 For all types of service. Liquid, up to 75 tons Refrigerant 22, 110 tons Refrigerant 22. Suction, up to 10 tons Refrigerant 12, 15 tons Refrigerant 22. For discharge gas, brine, water, steam, air or oil service. AMMONIA CONTROLS TYPE M3 TYPE R2 Solenoid liquid Valve*--up to 172 tons. Solenoid Suction Valves--up to 28 ton. Thermo Expansion Valves--from frac tional tonnage to 125 ton. Automatic Ex pansion Valves--from fractional tonnage to 60 ton. TYPE M91F TYPE TG TYPE UG TYPE TX VENTURI-FLO DISTRIBUTORS Wide application range. One piece; re place distributors requiring as many as 6 or 7 nozzles. FLOAT VALVES AND SWITCHES TYPE J56 electric floatswitch. For Re frigerant 12, 22, Methyl Chloride, Am monia and other non-corrosive liquids having a specific gravity of 0.6 or more. Up to 230 Volta, A.C or D.C. TYPE HK HIGH PRESSURE FLOAT VALVE. Up to 5 ton Refrigerant 12, 8 ton Refrigerant 22 and 20 ton Ammonia. TYPE E with strainer SUCTION LINE CONTROLS TYPE 771-772 SUCTION PRESSURE REGULATORS (Hold-Back Valves) Prevent motor over load. Refrigerant-12 and 22. . TYPE EPR EVAPORATOR PRES SURE REGULATOR For all refrigerants, with connection sizes up to 6 in. 908 LECTRO-LEVEL electronic remote control of liquid level. Accurate control for 'full-flooded evaporators. Adjustable to a wide range of level changes. Easy-to- set control dixla conveniently mounted in remote box. . ' flSMr TYPE 760 "EVAPOTROL" Pressure regulator--Vi ton. Refrigerant 12--V\ ton. Methyl Chloride. Controls and Instruments 271 BARBER-COLMAN COMPANY 1300 Rock Street, Rockford, Illinois Field Offices in 95 Cities Throughout the United States and Canada--consult local phone book A Complete Line of Electric and Electronic Controls Barber-Colman manufactures a complete line of automatic controls and control systems for heating, ventilating, and air conditioning applications for all types of buildings, large or small. Typical product lines are pictured on this page. A nationwide sales and service organisation offers experienced engineering assistance, qualified supervision of installation, and prompt, competent field maintenance assistance. Only Barber-Colman offers you years of combined experience in both automatic controls and air distribution and assumes undivided responsibility for delivering desirable indoor weather. (See Barber-Colman page in the Air System Equipment Section.) . - Product literature and application diagrams available. Please state your specific interest. Complete "Electrionic" Control Centers Motor-Operated Valves Unit Ventilator Controls A complete line of controls for all types of unit ventilators, including face and bypass, valve-controlled, electrically heated, and direct gas-firea classroom or auditorium types. "Package" sets are featured, designed for mounting entirely within the unit ventilator enclosure. These sets utilize a dual-element thermo stat combined with a motor operator for extremely accurate control of room and discharge air temperatures without the need for wall-mounted room thermo stats. Single- or double-seated valves for onoff or modulating control of steam, air, and water, and three-way valves for bypass or mixing applications. A complete line of compact motor opera tors is svailable.for two-position and proportional control. Modular Electronic Controls The "Electrionic" control center provides visual supervision of the entire heating and air conditioning systems and other mechanical or electrical functions, pro vides automatic control, and reduces installation and operation costs.- It in. eludes remote temperature indication, adjustment, and recording. Schemati cally diagramed, the control center pro vides "visual" supervision of the entire building. Ask for new booklet, "Electrionic*' Control Centers. - Thermostats . A complete line of single- and two-stage room and remote bulb thermostats for on-off control or proportional control. Humidity Controls Hair element or electronic type for twoposition (on-off) or proportional con tvraolvl eosf, mcoomtopr-roespseorarst,edrevlaaylvse, se, tsco. lenoid Motor Operators Spring return, unidirectional, reversible, multi-position, and proportional-type motor operators are available for opera tion of all types of dampers. Heavy-duty models are oil-submerged type. Adjust able speed is optional. Sequence Controllers Sequence controllers, consisting of a reversible oil-submerged driving motor to operate from two to six snap-acting switches, are available for roulti-Btep control of compressors, pumps, valves, or relays in refrigeration, air condition ing, or industrial processing applica tions. These controls translate temperature or humidity changes into voltage outputs which are amplified to operate relays. The relays, in turn, operate valves, motor operators, or other control devices. Complete custom control panels to meet any requirement are built up of one or more standard bridge circuit modules and one or more standard amplifier modules. Temperature bridges provide for use of one, two, or three standard sensing ele ments. Auxiliary bridge circuit modules are available to operate as many as three amplifiers in sequence. , Either two-position-or proportional am- . / plifiers are available. Dual compensator units, used with an amplifier module or combination of amplifier and bridge components, pro vide control for such applications as: outdoor reset of main element, stabiliza tion of discharge temperature, differen tial thermostat action, and lag element control. Accessories . The Barber-Colman accessory line.in cludes power boxes, transformers, color- coded thermostat cable, relays, switches, electric time switches, manual rheostats, polarized microrelays, and other items which go to make up o complete control system. '  272 Controls and Instruments GENERAL CONTROLS manufacturers of automatic controls for home, INDUSTRY AND THE MILITARY Glendale 1, California FACTORY BRANCH OFFICES SERVING ALL PRINCIPAL CITIES OF THE UNITED STATES AND CANADA SIX PLANTS: IRON MOUNTAIN, MICHIGAN GLENDALE, CALIFORNIA BURBANK, CALIFORNIA SKOKIE, ILLINOIS GUELPH, CANADA WARWICK, RHODE ISLAND T-270 T.90H110 T-190 THERMOSTATS New matched line of thermostats for heating and air conditioning-- horizontal and vertical models. Dis tinguished by compactness and beauty of appearance--for use in all . space heating remote control sys tems. Provide rapid response to radiant as well as converted heat. New mercury switch type. Heat Anticipator optional. Millivolt, 24-v and line voltage types to 13 amperes are available for heating and cool ing. AIR CONDITIONING CONTROLS Complete control systems for resi dential, commercial and industrial air conditioning. Thermostats for cooling and heating-cooling combi nation, system-coordinating Master Control Panels, and a line of refrig eration controls including thermal expansion valves, solenoid valves and refrigerant distributors. ELECTRICAL CONTROLS New Master Control Panels are packaged control systems combining all electrical components required for complete automatic control of refrigeration or air conditioning equipment. Electrical components such as relays, contactors, magnetic starters and transformers are also available individually. Controls and Instruments General Controls 273 V-110-1 HYDRAMOTOR VALVES MANUAL RESET VALVES . Equipped with manually-reset electromagnetically-held valve operator for safety shutoff of fuel supply to boilers. Valve can be opened only when current is applied and is closed by spring force on interruption of . current in response to high limit or safety switches. ^ in. to 6 in.; nor mally closed; screwed or flanged body; explosion-proof or weather proof. Factory Mutual and Under writers approved. Hydramotor valves, composed of electro-hydraulic actuators and valve bodies, are available in a wide range of types and sizes. Spring return for two-wire, current failure operation. Valve bodies and actua tors are offered in combination as complete self-contained units. Bod ies available in steel, brass, iron and alloy in sizes from % in. to 12 in., two-way and three-way bodies. Hy dramotor valves are particularly suited to safety shutoff applications and control of steam, hot and/or chilled water systems. BOILER COMBUSTION CONTROL SYSTEMS For improved efficiency and better operational maintenance, General Controls offers an outstanding line of combustion controls and instru ments suitable for use with oil, gas or stoker-fired boiler room installa tions in industrial and commercial installations. Included in the line are Flue Gas Temperature Indicator, Draft Gage, Steam Pressure Con troller/Indicator, Draft Program Control, Air Pressure Gage. Ail are flush or surface mounted. if i ( K-SA. X' K-3A. 1M' K-SE 2M' MAGNETIC GAS VALVES Magnetic, current failure, quiet, two-wire. Opens and closes fuel line supply at demand of room thermo stat, limit control or similar device. Widely used for controlling gas to warm air furnaces, gas fired boilers, industrial furnaces, conversion bur ners; etc. Compact; low current con sumption; humless % in.- to 6 in. IPS for pressures up to 5 lb; a-c or d-c. Also available in explosionproof model. B-63 COMBINATION GAS VALVES For ultimate space economy, an electric diaphragm gas valve com bined with pilot valve, gas cock and low pressure regulator. B-53 models for 24-v systems have provision for optional plug-in thermopilot relay for safety shut-off in event of pilot failure. B-63 self-powered millivolt models inherently fail safe upon pilot failure, since operating power is generated from pilot flame heat. SLOW-OPENING GAS VALVES New combustion control afforded by these diaphragm-controlled gas valves. Governor regulates fuel sup ply to burner in direct ratio to steam pressure, eliminating hunting aspect common to most pilot throttling valves. Low fire adjustment pre vents main valve or gas flow from reducing below adjustable set mini mum, affording fullest advantage of gas burner installed. Type B-55G-1 pictured, available 1 in. to 6 in. in IPS. U REFRIGERATION AND INDUSTRIAL SOLENOID VALVES Available in a range of sizes from M in. pipe size midget valves to 6 in. pipe size. Pressure range to 1000 psL Body construction in cast iron, forged brass, carbon steel, stainless steel ami special alloys. Available in two-way, three-way, four-way, normally open, normally closed and manually reset models. Diregji acting types, also pilot oper ated, diaphragm type, lever-.acting types. Available in a variety, of coils for special applications such as mobile applications. HAMMEL-DAHL AUTOMATIC CONTROL VALVES Pneumatic and hydraulic actuators for fluid control from a Micro-Flo basis up to the largest type. Pneu matic diaphragm motors feature re movable actuators, reversible super structures, and a wide variety of material for body, lining and dia phragm. Body assemblies include globe, angle, Saunders, three-way and butterfly designs. Particularly suited for high temperature hot water systems. TIME SWITCHES For-commercial and industrial sys tems or processes for automatic onoff control. Available in 7-day models and also 24, 12, 8, 4, 2, 1 hour rotations. Electric or springwound models. Snap switch or mercury switch.  274 Controls and Instruments HENRY VALVE COMPANY 3215 NORTH AVENUE, MELROSE PARK, ILLINOIS (Chicago Suburb) CABLE: HEVALCO, MELROSE PARK, ILLINOIS Manufacturers of Valves, Driers, Strainers, Fittings and Accessories for Refrigeration, Air Conditioning and Industrial Applications. "GOLDEN BANTAM" PACKLESS VALVE--TYPE 516 A small packless line shut-off valve with V< in. through Vs in. flare, ODS or extended end solder connections. Also "Blue Bantam" and "Standard" Balanced-Action packless line shut-off valves with V\ in. through 5/a in. FI. and lA in. through lH in. ODS size connections. CROSS-VU HERMETIC SEAL LIQUID INDICATOR-TYPE LI-16 Brass indicator with glass fused directly to metal body. Maximum work ing pressure 500 PSI Connection sizes: Y* in. through Vs in. M.F1., M.FL x F.Fl. or with extended ends and solder connections.' WING CAP PACKED VALVES--TYPE 203 The standard of the industry. Bronze alloy with ODS connections in sizes 7/s in. through 4Vfc in. (Globe) and Vi in. through 3Ys in. (Angle). Also semi-steel with Ys in. through 2Ys in- F.P.T, connections and semi-steel flanged type globe, and angle valves with brass ODS or steel butt-weld adapters, and one piece socket weld or F.P.T. flanges in a wide range of sizes from 1 in. to 5|/g in. Write fox catalogs describing the complete line. ANGLE RELIEF VALVE--TYPE 52 {UVj ASME--NB--National Board Certified Forged brass automatic pressure relief valve. Pressure setting range 50 to 450 PSI Size connections: (MPT Inlet x Flare Outlet) Vi in. x Vs m., Vi in x Vi in., Vs in. x Ys in- and Ys in. x Vi in. Also Vs in. ODS x Vs in. ODS. . . "DRI-COR" FILTER-DRIER--TYPE V800 Ceramic fired desiccant filter-core in bed of granular desiccant--a blend of molecular sieves and activated alumina. Provides high capacity drying even at relatively high temperatures, micronic filtration, efficient acid re moval and low pressure drop. Pressure sealed. Wide range of sizes with y4 in. through A in. FL connections. "DRI-COR" Filter-Drier Cartridges also available for Henry Cartridge Type Angle Driers. "Y" STRAINER--TYPE 895 Flanged design permits cleaning without removing strainer from line. Screen cylinders securely located by spring tension prevents by-passing of refrigerant. Forged brass end caps with integral end connections. Screen area: 10 through 150 sq in. Size connections: H in* through 4Ys in. ODS. Angle and straight-through type strainers also-available. mbmtI Catalog 103 --^1 Valves, Driers, I Strainers and PyS" I Accessories. Catalog SOS Ammonia: Valves and^ 1 Accessories? Catalog FF Forged S Carbon Steel Fittings. Controls and Instruments 275 Illinois Testing Laboratories, Inc. Room 516, 420 N. La Salle Si., Chicago 10, Illinois dfourt FOR PRECISE MEASUREMENT OF TEMPERATURE... AIR VELOCITY... DEW POINT... PYROMETERS autodave*, pipe Doe* <1 tares ere desired. A complete Dne of single or multiple-point pyrometers--portable or mounted--for temperature measurement In oil types of service. Particularly adopted to exhaust, cooling water and lubricating oil tempera ture measurements on diesel and gos engines. For furnaces, bins, ovens, vats, pots, beat exchangers, kettles, reactors, any similar equipment where accurate tempero- PYROCON A self-contained, hand-held portable con tact pyrometer. Takes any surface temper ature. Widely used in plastic molding, chemical processing, electrical, rubber and paper manufacturing industries. Available with fixed or flexible arm. VEIOMETERS An instantaneous air velocity meter^giving direct readings in feet per minute without necessity of timing, calculation, or reference' to tables or charts. A compact, selfcontained, portable unit. For low range readings, Velometer b held ta air streora. For high range readings, tabe-cocmecied special jets provide convenient use In any i. Standard ranges from 20 f.pjn, to 24,000 f.pjn DEWPOINTERS An improved instrument far simple, rapid dew paint reading of any gas. Indication take* place In an enclosed observation chamber under accurately controlled con ditions. Pew or fog suspended In air--not on mirrored surface--makes It easy for two or more observers to get (he seme accurate results. The Absor Dewpointer b a complete, self-contained unit--no external cocAonts or other apparatus are required. SURFACE PYROMETER The Atnor type 2300 Pyrometer sets o new high in precision measurement of low sur face - temperatures. Special design, from' AWco magnet to-quick reacting thermo-, couple, for accuracy...speed and depend ability.Thb U a self-contained, sturdy unit --. easfly carried and Used anywhere on a wide variety of applications. Direct ' reading, six-inch mirrored scale b easily read...quickly understood. The Instrument b available in five Fahrenheit scale ranges with a span as small a* 150s. Automatic cold PORTABLE PYROMETER The Alnor type 1500 b designed for work with electrically heated mantles. Thb light weight, magnetically shielded pyrometer gives fast, precise temperature reading to/ production men in afl industries. Choice of ten scale rouges, 0-400 to 0-3000F. otor b standard equipment. dtffurt ILLINOIS TESTING LABORATORIES, INC Room 516, 420 N. La 5alle St.-Chicago 10, Illinois  276 Controls and Instruments JOHNSON SERVICE COMPANY AUTOMATIC TEMPERATURE AND AIR CONDITIONING CONTROL General Office & Factory 507 E. Michigan St. Milwaukee 1, Wis- Direct Branch Offices in Principal Cities Johnson Controls Ltd., 120 Bermondsey Rd., Toronto 16, Ont. T-901 Liquid* filled Remote Bulb Submaster Thermostat R-316 Air Flow Controller MANUFACTURERS, ENGINEERS and'CONTRACTORS--A complete line of automatic temperature and humidity controls for beating, cooling, ventilating, sir conditioning, industrial processing, military installations and special temperature and humidity control applications. SPACE CONTROL--Automatic room temperature and humidity control for con vectors, radiators, radiant heating, unit ventilators, unit heaters, and beating and cooling air delivery equipment. INDUSTRIAL PROCESSING--Automatic temperature and humidity control for every requirement in manufacturing and industrial processing. Thermostats, valves, dampers for tanks, dryers, vats, kettles, curing rooms, coolers, kilns, and other special equipment in textile, rubber, paper, petroleum, meat, dairy, baking, sugar, brewing, distilling, tanning, candy, foods, pharmaceutical, and other in dustries. SERVICE ORGANIZATION--JOHNSON sales engineers and trained installa tion experts at all branches in United States and Canada. No agents, jobbers, or part-time representatives! All Johnson salaried personnel for exclusive service of Johnson Service Company customers. JOHNSON LITERATURE: Available at your nearest JOHNSON branch office or write to address above. JOHNSON THERMOSTATS Room Thermostats--single and dual temperature (Day-Night, Heating and Cool ing). Proportional or two-position action. Maintain temperatures within one degree above or below setting. Wide selection of adjusting features, guards, and mounting. Furnished with or without thermometers. Insertion and Immersion Thermostats--Liquid-filled temperature measuring elements. Stem type for direct measurement. Remote bulb types for applications re quiring location of thermostat at a distance from the point of temperature measure ment. Various bulb styles available. Standard capillary length is 8 ft. Lengths of IS, 25, 35, 50, 65, 75, and 85 ft available on special order. Submaster Thermostats--The set point of these Johnson controllers is changed from a remote location by the action of another (master) controller. Available with liquid-filled stem and remote bulb measuring elements. Johnson `.`Duo-Stats," weather compensated primary controllers, control heating system temperatures in accordance with the outdoor temperature. Duo-Stats are available for any heating system, all types of buildings, and furnished in pneumatic, electric or electronic models. . PRESSURE CONTROLLERS Pressure Regulators with ranges of 30 inches of water to 300 psi. Static pressure regu lators measure variations in pressure from 0.009 inches to 3 inches of water. Used also as differential regulators measuring difference in pressure between two chambers. Pressure switches and governors also available. ' The Johnson Air Flow Controller is applied to mixing boxes of high velocity, high pressure, dual duet air conditioning systems. Provides positive constant volume air discharge through each mixing box. Operates at any pressure difference from ap proximately 0 to 1 inch wg and will produce a 1 psi air pressure change on pressuredifference changes of less than 0.005 inch wg. JOHNSON HUMIDITY CONTROL Humidostats--Room and insertion types with humidity measuring elements of wood or animal membrane, the most sensitive of which controls within 1 percent at relative humidities as high as 95 percent, at temperatures of 200 F. Submaster models also available which are adjustable from a remote point by another controller (master) or may be manually readjusted from a remote point by means of a Johnson Gradual Switch. , Humidifiers--Steam grid (perforated pipe supplied with low pressure steam) or pan type with copper evaporating pan, brass or copper heating coils and float control. Series T-400 Room Ther mostat T-894 Liquidfilled -Immersion Thermostat R-1051 Static Pressure Indica tor-Controller Controls and Instruments Johnson Service Co. 277 T-1210 Room Temperature Transmitter 12 Point Model Pneumatic Step Controller PNEUMATIC TRANSMISSION Johnson pneumatic transmission systems provide a greatly amplified and superior means of centralized indication and control for modem air conditioning, hearing and ventilating systems. Control centers are custom designed to fit the requirements of the individual building. Johnson offers a complete line of pneumatic transmission and control center instrumentation, including room transmitters, remote bulb transmitters, indicators, receiver-controllers, recorders and related apparatus. SPECIAL CONTROLLERS Aspirating Cabinets--Several* models with many combinations of controlling and auxiliary devices required to provide control of temperature and humidity. Cabinets equipped with blowers for positive air circulation and air gauges for checking func tion of controllers at all times. Pilot Positioners--for dependable and accurate repositioning power. Applied to valves and damper operators. Respond to smallest changes in air pressure. New Precision Pilot acts 6 times faster than ordinary pilots. Pneumatic Step Controllers--for capacity control of reciprocating refrigeration equipment or any application where sequence of pressure switches is used. Record-O-Stat--Combination eapillary temperature controller and recorder. Avail able in single-pen, two-pen, and submaster models.* Indicating controllers and recorder-controllers also available. Liquid Level Regulators--(Float Type) control within extremely close limits. Mounted through wall of containing vessel by stem with 1-inch pipe thread. Floats of copper, stainless steel or special alloys. Thermometers--Insertion and immersion types for air and liquids. Stem and re mote bulb temperature measuring models with vapor tension or liquid filled elementsVariety of styles, mountings and finishes. T-1270 Receiver Controller V-530 Precision Pilot Positioner Applied to Valve V-1S3 "Sylphon*' Convector Valve JOHNSON VALVES Johnson Diaphragm Valves--Simple, rugged. Diaphragms of special molded rub ber, resistant to age and oxidation, operate valve steins against spring pressure. Available also with "Sylphon'* seamless metal bellows. In standard sires and pat terns including compact valves for convectors and unit conditioners. Normally open or normally closed. Three-way mixing and by-pass valves, for water, brine and other liquids. ' Johnson "Streamline" Diaphragm Valves--With modulating plugs and special internal construction. Smooth proportional control. Where greater power is required for repositioning at slightest demand of controlling instruments, the larger molded rubber diaphragm valves are fitted with pilot positioners. Series V-210 and V-214 Three-Way Valves--for mixing and by-pass applications. 100 percent tight closing. Can be serviced without removal from the line. Sizes to 6 in. 125 and 250 lb standard construction. T-1000 Single Pen* O-Stat Record* O-Stat V-210 Three-Way By-Pass Valve D-223 Propor tioning Louver Damper JOHNSON DAMPERS AND SWITCHES Standard Johnson Dampers--Galvanised 16-gauge steelblades in flat steel frames with adequate tracing to form rigid assembly. Black lacquer or special corrosionresisting finishes- Angle iron frames optional. Special Dampers--Galvanised iron frames and monel metal, aluminum, copper or rust-resisting steel blades on special order. Frames of same material as blades, if desired. Brass pins in steel bearings or ball bearings. Johnson Damper Operators--Similar in operating principle to valves. Specially molded rubber diaphragm or seamless metal bellows operates damper through suit able linkage. Johnson "piston" damper operators afford long travel at full power. With or without pilot mechanism, as described for "Valves." Johnson Pneumatic Switches--For direct operation of dampers and to switch controllers in and out of service from remote locations- Standard switchboard pontiff are Masonite. Ebony, asbestos, steel, polished oak and genuine or imitation marble panels on special order. Special switchboards including all types of control equip ment available on special order. D-251 Piston Damper Operator {  278 Controls and instruments LESLIE CO., 237 Grant Avenue, Lyndhurst, New Jersey Diophragm Control Valve Clou D-1 Temperature Regulator Oau T REGULATORS and CONTROLLERS for the Regulation and Control of Pressure, Temperature, Flow and Liquid Level Control Pilot Type PD SeU-Oeoning Strainer Pump Governor Class PR Reducing Valve Class 1-3 Floatless Level Control for Boilers, Tanks, Evaporators, Heaters, Standpipes, etc. ISSUE COAST-TO-COAST SERVICE--In all principal indus trial centers LESLIE factory.trained engineers arc available to help with any control problem involving steam, liquid, air or gas. Look for LESLIE REGULATORS under "Valves" or "Regulators" in your classified telephone directory. INTERCHANGEABILITY--All interna! oarts of LESLIE Regu lators are dimensionally interchangeable and have maximum interchangeability in all sizes and classes. LESLIE SPECIAL FEATURES--at rto extra cost! Stellited Seat Rings . Hardened Stainless Steel Main Valves, 500 Brinell Corrosion Resistant Springs Hardened Stainless Steel Cylinder Liners, 500 Brinell Supplied as standard equipment. . LESLIE PRESSURE REDUCING VALVES, PUMP GOVERNORS, and TEMPERATURE REGULATORS -- Self-contained,, spring loaded, interna) pilot piston or diaphragm operated with stellited seat rings, hardened stainless steel trim, bronze, iron, or steel construction. ALL LESLIE Regulators feature: High accuracy of regulation Single-seated construction.for pos - ittue dead-end shutoff Quick valve action for sudden load changes Maximum resistance to corrosion and tcear Maximum spring range -- from minimum to maximum of the range' without change of spring or diaphragm Controls and Instruments m ikiiml COMPANY 12200 Beech Road, Detroit 39, Michigan GAS APPLIANCE PRESSURE REGULATORS 279 FOR MAIN BURNER LOAD APPLICATIONS DIMENSIONS DRAW ING MOOR RV-10* ik 1% 2H 0 k RV-30* 2K 2VU 3M H 1 RV-30A* 2% 2K* 2VU * fCH H 1% K. 1% 2Vi* 2tt* 2 RV-31* 2V, 2Vu VA% H H PM 2K. RV-41* 2*Vi 2% 3% 3 RV-41A* 2 2% 3K 1% \,lA* RV-42 2Vi 3K 4Vi, IK m VA> IK RV-50 3 ?'A* 9A IK I'M. IK m* 4 RV-51 3* 4Vi VA* 2K. 2Y, IK 2K RV-60 4K 9A\ 7<A TA% 2Hfo lnM 2% RV-81 6 7 8% U2K 2K VAt 3K 5 RV-91 7K 9K m 2H- 3K !4- RV-no 9 12H UK 3K' 4K 5'Ki 6 outlet NOMINAL PRESSURE size ADJUST SHIP- (INCHES) MENT WT. INLET OUTLET INCHES x. Af K K H# K K K H K K 2-5 2-5 2-5 2-5 K K# K H K 'Att K K K K K K H K 3-4 3-4 3-4 3-4 34 34 H-# 'K -K K K 2-5 2-5 H# K K H# K 1# K K IK# K 1 K 3.5--4;5 K 3.5--4.5 K 2-5 K 2-5 K 2-5 K 2-5 1 2-5 2K# l IK 1 IK 2-5 2-5 5# m IK IK IK 2-5 2-S 9# 2 2K 2 2K 2-5 2-5 20# 2K 3 ZK 3 2-5 2-5 PRESSURE DROP CAPACITY U' ex. Prawn Ora Btt/to Bto/to aft/to SB SB/a ft SBBto/caf! Map it ap Gas UtopGs 15 11.000 7.450 81 60,000 40.500 St 60.0(10 40.500 88 65,000 44,000 81 60.000 40,500 81 60.000 40,500 88 65.000 44.000 SI 60.000 40.500 81 60,000 40.500 88 65.000 44.000 126 93.000 61,000 135 100.000 67.500 126 93.000 135 100.000 61,000 67.500 170 126.000 85.000 270 200.000 135.000 270 200.000 135.000 450 333.000 225.000 460 340.000 230.000 76 500,200 333,000 705 521.700 352.500 1250 925.000 625.000 1260 932.400 630.000 2030 1.502.200 1.015.000 2030 1.502.200 1.015.000 4200 3.108.000 2.100.000 4900 3.626.000 2.450.000 REGULATION CAPACITIES Stn/tr-eISto/orfl, R7sp i Gjs* * (MAXIMUM) (MINIMUM) 17,000 1.700 100.000 100,000 100.000 10,000 10.000 10,000 100.000 100,000 100.000- 10,000 10.000 10.000 100,000 10,000 100.000 - 10.000 100,000 10.000 152.000 174.000 15.200 17.400 152.000 174.000 15400 . 17,400 196,000 19.600 310.000 310.000 31.000 31.000 517.000 527.000 51.700 52.700 775.000 810.000 77.500 51.000 1.430.000 1.450.000 143.000 145.000 2.330.000 2430.000 233.000 233.000 4.850.000 5.650.000 455.000 565.000 * These muftis also available A.G.A. certified for main burner and pilot load applications (minimum capacity 120 btu/hr). * To convert to Btu/hr--0.6 sp gr Gas, multiply by .675. PRESSURE SETTINGS: Standard outlet pressure settings for the various models are as follows: - RV-10...................................................................... 3.0 in. w.c. RV-30, RV-30A and RV-31.................................. in. wjj. RV-41^ in., RAM1AM in., RV-41 AH in-........... 4.0 in. w.c. BV-41H in., RV-42, RV-50................................. ) RV-51, RV-60,......................................................\ 3.5 in. w.c. - RV-81, RV-91............................... .......................J . RV-UO*..................................................................... 4.0 in. we. Upon Request, any Maxitrol gas regulator will be adjusted to any other pressure within the range of the standard spring at no extra charge. ' .' INLET PRESSURES: All Maxitrol- gas regulators can be satisfactorily operated at in let pressures up to one psi. Under certain circumstances even higher inlet pressures are permissible. Consult factory. - MULTI-POISE MOUNTING: "Straight-Thru-Flow" series regulators should not be installed in a vertical pipe run if the gas is flowing upward. Otherwise, all Maxitrol gas regulators may be installed in any plane at any angle. VENTS: Position--Models RV-42, RV-50, RV-51; and RV-60 are manu factured with horizontal vent outlets. Various vent positions are available. Consult catalog 57. The vent boss on all other regulators is located vertically over the outlet end of the regu lator. Boss Sire--All models except RV-10, and RV-110 are tapped with Vi in. NPT. RV-10, no tapped boas. RV-110, boss tapped V* in. NPT.  280 Controls and Instruments THE MERCOID CORPORATION Main Office and Factory, 4201 Belmont Ave., Chicago 41, 111. NEW YORK 17, N. Y. 205 E. 42nd Street PHILADELPHIA 32, PA. 3137 E. Broad Street - Automatic Controls for Heating, Air Conditioning, Refrigeration and Industrial Applications Complete line of Mercoid Controls and mercury switches shown in Catalog No. 858A SERIES "D" PRESSURE CONTROLS General Purpose Type (Nema 1): For indoor service and other general purpose applications. Equipped with outside adjustments, visible calibrated dial, visible on-on hermetically sealed mer cury contact. Available in 23 pressure ranges from 0-30 in. vac. to 300-2500 psi with differential varying from 2 os to 150 psi depending upon range selected. Weather Resistant Type (Nema 1A, 2, 3, 4): For outdoor service and other ap plications. Hm external adjustments, visible dial, hermetically sealed mercury contact. Available with same operating ^ranges as noted under general purpose types. Explosion-Proof, Class 1, Group C (Nema 7), Class 2, Group E, F, A G (Nema 9, 9A): For hazardous locations. A new light weight control (8K lbs) equipped with external adjustments, visible calibrated dial and visible on-off hermetically sealed mercury contacts. Available with same operating ranges as noted under general purpose pressure controls. SERIES "D" TEMPERATURE CONTROLS For liquids or gases, such as air, oil, water, paraffin or distillate vapors and . other industrial applications. Equipped with outside adjustments, visible dial and visible on-off hermetically sealed mercury contact. Operating ranges from 30 to plus 60F., up to 370-530F. Avail able with Weather-Proof or ExplosionProof enclosures. LIQUID LEVEL CONTROLS Various types available such as for boiler feed water pump control, combination pressure and low water control or for use where low specific gravity liquids are ' used. Can be furnished with explosionproof ease for hazardous locations. If you have a control problem involving the automatic con trol of pressure, temperature, liquid level, mechanical opera tions, etc., it will pay you to consult Mercoid's engineering staff--always at your service. - TRANSFORMER -RELAYS Type V, a reliable low voltage mercury contact relay which also acts as a trans former, inducing low voltage (24 volts) on the pilot eircuit. Used for all types of automatic equipment. Available in various voltages, cycles and eircuit ar rangements. VISAFLAME CONTROL For direct burning mounting. Operates direct from the light of the instead of from the heat in the stack. Used with a* Mercoid panel unit for either inter mittent or constant ignition burners. Provides full protection against flame, ignition and power failure. OIL BURNER SAFETY AND IGNITION CONTROLS v Type JMI, a stack safety control, for positive protection against flame or ignition. Also provides complete protec tion against low line voltage or power failure. Type JM, available for constant ignitioQ burners. LOW VOLTAGE THERMOSTAT The Mercoid Sensatherm is a very sensitive room thermostat, operating on a differential of H*F. No internal heater coils or other means of artificial accelera tion are used to maintain an even room temperature. ` LINE VOLTAGE THERMOSTATS For direct control of motors operating automatic equipment. No relay required. These thermostats incorporate a liquid charged bellows. Expansion and con traction of the bellows tilts a Mercoid mercury to mercury contact to open or close the electric circuit. Standard ranges: 56-80, 65-90, 38-70, and 2560F. Available with manual on-off switch for use with industrial unit heaters. Can be furnished with explosionproof housing for hazardous locations. LEVER ARM CONTROLS Mercoid lever arm controls have a variety of applications where it is desired to mechanically open and close electric circuits. Mercoid float controls are used for maintaining fluid levels in tanks, or for control of sump pumps, etc. Controls and Instruments 281 MINNEAPOLIS-HONEYWELL REGULATOR CO. Minneapolis, Minnesota A COMPLETE LINE OF PNEUMATIC, ELECTRIC, ELECTRONIC CONTROLS AND INSTRUMENTS Supervisory DataCectter* allows one man to supervise and control all the mechanical systems of building from a central location; remotely check and adjust temperatures, start and stop compressors, pumps and fans. A new - Sdectografic* panel dearly dis plays the desired mechanical system on a single small screen, while the multipurpose coatrol board is automatically switched to chat system. This new feature permits all graphic layouts to be shown, yet requires less wiring, is smaller and standardized. Panel location and space requirements can be de termined early in the budding's design. Addi tional functions can be incorporated by adding modular units. You can took to Honeywell for all your control needs-- centralized panels, instruments, valves--because Honeywell has a complete line available. You'll get quick service from 112 offices across the nation, each staffed with control spe cialists who will assist and advise you. Contact Hoaeywell Electronlk* temperature indicator gives an unlimited number of remote tempera ture readings on one instrument. Accurate co l/5 of a degree. Remote readings can be taken of any point in the air-conditioning system simply by pressing a button. Re quires less than a square foot of panel space. even before blueprints are started to insure efficiency, saving, satisfaction. Shown below are three typical control valves in Honey well's complete line of electric and pneumatic valves for commercial and industrial applications. I: i '` KL Three way electric valve controls liquids in either mixing service or in systems requir ing flow be directed from either of cwo inlets to s' common oudet. Constant total flow throughout full plug travel. Scrain release mechanism insures tight close-off without motor strain. Sizes: screwed--V4 in. co 2 io.; flanged--2H in. to 4 in. *Trmdtmark Single seated pneumatic valve used for normally closed modulating control ofsteam, hot water, or cold water on heating or air conditioning coils. Also for general purpose , --zone systems, booster coils, cooling units using water, etc. Equal percentage, high lift plug. Sizes: screwed--W in. to 3 in.; flanged --2Vt in. to 6 in. Industrial diaphragm-control valve. Three-way valve used for mixing service with two inlets, one oudet, or for diverting service. Normally open to bottom port. Linear flow characteristic. Rangeability: 30 to 1 for each port. Maximum operating aix pressure 33 psi. Sizes: screwed--14 in. to 2 in. FOR COMPLETE INFORMATION CALL YOUR NEAREST HONEYWELL SALES OFFICE 11 >282 Controls and Instruments MOELLER INSTRUMENT COMPANY SINCE 1867 132nd STREET & 89th AVENUE, RICHMOND HILL, NEW YORK, N.Y., U.S.A Representatives in Principal Citi cs MOELLER INDUSTRIAL THERMOMETERS made in ail forms. Straight, Angle, Right Side Angle, Left Side Angle, Reclined and Inclined Angles, in scale ranges from minus 120 to plus j 125F. or its equivalent in centigrade. Available in 5', 7", 9 and 12' scale sizes with plain stems, union connection stems and separable sockets in all stem lengths and alloys. RECORDING THERMOMETERS, Mercury Actuated^ made in the round or rectangular cases. Charts 10r or 12', l hour, 12 hour, 24 hour or 7 day. Ranges from minus 40 to plus 1000*F. or its equivalent in centigrade. Made in remote reading, direct reading, portable and self contained styles. Plain stems, unioa connection stems and separable sockets in all stem lengths and alloys. OIAl INDICATING THERMOMETERS, Mercury Actuated, made in 4'A', <5* and S'A' sizes with flexible extension tubing. Adjustable rigid stems, single or two pointers, plain bulb, onion connection bulb or separable sockets in all lengths and alloys. Scale ranges from minus 40 to plus 1000*F. or its equivalent in centigrade. THERMOMETER TEST WELLS, THERMOCOUPLE PROTECT ING TUBES and WELLS, made up in all sizes and alloys. RECORDING PSYCHROMETERS, Mercury Actuated. Round and Rectangular Case, 12 hour, 24 hour or 7 day charts, self contained or remote reading, with or without motor driven fan. ENGRAVED STEM ond PORCELAIN and PAPER SCALE THERMOMETERS made in ranges from minus I SO to plus 1125'F. or its equivalent in centigrade. Available in stand ard and extreme precision grade. Made to meet specifications of the Government, A.S.T.M. and other authoritative bodies. HYDROMETERS PLAIN FORM or COMBINED with THER MOMETER. Made in all scales specific Gravity or Bamne for heavy and light liquids. Brix, Twaddle, Ballings Scales, etc. available for all liquids. Standard and commercial grades. Controls and Instruments 283 PEnn comrols. inc. Goshen, Indiana In Canada: Scarborough, Ontario Export Div. 27 E. 38th St., New York 16, N. Y. Offices and Representatives Albuquerque, N. M.--Decatur, Ga.--Berkeley 2, Calif.--Newton 58, Mass.--Chicago 11, 111.--Cleveland 3, Ohio-- Columbus 21, Ohio--Dallas 7, Texas--Dayton 20, Ohio--Denver 2, Colo.--Houston 22, Texas--Los Angeles 26, Calif.--Milwaukee 5, Wis.--Moline, 111.--Minneapolis 19, Minn.--North Bergen, N. J.-- Philadelphia 11, Pa.--Pittsburgh 16, Pa.--Rochester 18, N. Y.--St. Louis 10, Mo.--Salt Lake City I, Utah---Seattle 1, Wash.--Wichita 2, Kans. - Wholesalers and Warehouses in Principal Cities AIR CONDITIONING AND COMMER CIAL COOLING CONTROLS DOMESTIC HEATING CONTROLS Fan Center to control the fan coil unit on residential air conditioning with remote cooling equipment. Compact ... only 4Vi in. wide and 6 in. high... it combines a trans former with fan relay, reset relay and heating relay ... one or all. Cooling Center for control of re mote condensing unit or water chiller. Only 7 in. high and 8 in. wide, it combines pressure controls, contactor, auxiliary relay for (a) water chiller pump, (b) tower pump or fan relay or both, (c) condenser fan relay. Series 275 Oil Protection Con trol for pressure-lubricated com pressors. Stops operation of refrig erating equipment before a failure in oil pressure system can damage the unit. Features a 90-second timedelay switch with manual reset to re-start compressor. Series 273 Dual Pressure, 2-pole, refrigeration control handles poly phase motors without use of mag netic-starter. With its 2 separate circuits, each unit is really 2 switches in 1. Available in single function control, also temperature models in single and dual function. Series 246 Water Valve for pres sure or temperature application on water-cooled refrigeration compres sors and condensers. All range de sign handles both R-12 and R-22. Threaded and flange models. Also 2-piece valves for hermetic systems. 3-Way Water Valve designed for atmospheric or forced draft cooling towers. For use on single or multiple condenser hook-ups to provide the most economical and efficient use of the tower regardless of surround ing air temperature or humidity. Available in Vi in., Y\ in., 1 in. and 114 in. sizes. Series 888 Rimset Thermostat designed for close control of room temperatures in heating, cooling or combination year, 'round air-conditioning systems. Thermostat unit is interchangeable with various sub bases to handle 12 different heating and cooling jobs. AU wiring is on sub-base ... you simply "plug in" the thermostat. Series 926 Gas Valve features straight-through flow and vertical self-cleaning seat. Designed for Vi lb pressure on all types of gas. Pressure regulators and pilots are also available. Series 680 Stack Switch for con tinuous or intermittent ignition oil burners. Available in either single or two-unit models. Features lowvoltage protection and automatic recycling on power interruption. Type 520 Fan, Limit Control for warm air furnaces. Liquid expansion type in either combination fan and limit or separate models for fan and limit control. Safety limit controls for hot water jobs also available. AUTOMATIC CONTROLS FOR HEATING, REFRIGERATION, AIR CONDITIONING, APPLIANCES, PUMPS, AIR COMPRESSORS, ENGINES  284 Controls and Instruments THE POWERS REGULATOR COMPANY Specialists in Thermostatic Control Since 1891 Factory and General Offices, Skokie 84, III. OFFICES THROUGHOUT UNITED STATES AND CANADA New York 17, N. Y.: 731 East 46fh St. Chicago 26, lfl-! 6655 Sidg Bfvd. Los Angela 26, Calif.: 3200 W. Temple St. * Toronto, Ont.: 15 Torbarfie Rd. CONTROL SYSTEMS FOR HEATING, VENTILATING, AIR CONDITIONING and Processes, also Hot Water Supply Controls Room Thermostat Ilygrostat When you specify or install a Powers System of Temperature Control you can rely on Powers complete responsibility for a correctly engineered control system, proper installation, continuous successful operation and SERVICE when required from offices in 85 cities. Some of the many controls employed in a Powers pneumatic system are shown here. A few hot water supply controls are shown at bottom of opposite page. For engineering assistance or bulletins contact your nearest Powers office or write nearest office listed above. Pneumatic Room Thermostats, Hygrostats, Damper Motors Powers Thermostats provide true gradual action for precise automatic control of room temperatures. They are available for single temperature control with direct or reverse action; two temperature or day-night con trol with direct action only; heating-cooling for air-conditioning control is also avail able with remote bulb; and submaster type with control point readjctstable by a remote master instrument. Powers Hygrostau are designed for pneu matic control of valves, dampers and sim ilar devices used with various types of humidifying equipment. They are available for single point control for room or duct installations, direct or reverse action; for submaster control with reverse action and with direct or reverse adjustment, POWERsi ttOKE Dampea- Motors are piston type for gradual control of dampers or other final control elements. Available in three sizes: 3 in. (2 in. stroke) far limited space applications, 4 in. (3 in. stroke) and 6 in. (4 in. stroke) for smooth gradual control of automatic dampers up to 32 sq. h. or for other applications. Powers PACKLESS Control Valves eliminate pack ing maintenance and damage from water leakage. Heating-Cooling Thermostat Powerstrolce Motor POWERTOP Valves are designed for smooth proportional control of steam or water flow. With 10 sq. in. effective diaphragm area, it is a compact unit for limited space applications such as unit ventila tors, radiant panels, reheat coils, etc. Sizes: hi in^ % in. and 1 in. with angle union or globe union bodies. Powcrtop Control Valve Convector Valves are extremely compact and especially adapted to very limited space applications. Available in three body types: angle union, globe union and reverse flow union. Angle and globe type sizes are hi in. and % uL, reverse flow % in. Powers LIMITEM Thermostat is a precision instrument for: (1) low limit control of unit ventilators (2) return air, mixed air and fan discharge temperature control with central fan systems and (3) pipe line insertion when used with a well. It provides convenient adjust ment for any control point between 35 F and 185 F. Various mount ing arrangements can be supplied. Convector Valve Limitem Thermostat Series 200 SUBMASTER Indicating Regulator has a control point that is pneumatically, readjusted by a master instrument. It is available with sensitivity adjustment, direct or reverse action, and with direct or reverse reset adjustment. ' Series 200 Submaster Controls and Instruments The Powers Regulator Co. POWERS GRAPH-O-MATIC PANELS Powers central control panels combine precise instrumentation with simplicity of operation. They can be equipped to take care of a variety of functions such as remote readjustment of controllers, continuous temperature indicators, remote positioning of dampers and valves. Simplicity of pneumatic controls insures- continuous and reliable service, Graph-O-Matic Panels are also available in console models. All types are custom designed and built to meet the requirements of any comfort or process control system. 285 Flowrite Valves No. 11 Regulator Transmitters, Receiver Controllers, Gages The Type HT Transmitter is available for room and duct installa tion. Ranges are 35 F to 65 F, SS F to 85 F, 75 F to 105 F, and 95 F to 125 F. The Series 200 Remote Bulb Transmitter is available with bulbs for duct or pipe line insertion and with 15 ft. of capillary tub ing. Standard ranges: --25 F to IS F and 25 F to 250 F. Series 200 Receiver-Controller receives pneumatic signals bom a remotely located transmitter. It indicates the temperature at tbe remote location and also controls a valve or damper to maintain opera tion at the selected control point. It is furnished with adjustable sensitivity and with direct or reverse action. Standard indicating scales are --25 to +135 F and 25 F to 250 F. Temperature Gages continuously show the temperature of important phases of an air-conditioning or process system. They are designed for central panel mounting remote from the transmitter. Diameters are Zhi in- and 3hi in. Powers Indicator Gages are used to show the reset range of a controller, the operation of electrical equipment or the position of a valve or damper motor. - Pneumatic Transmitters Trpe HT ibwe. Scries 200 bdw Powers Pneumatic Switches and FLOWRITE Valves Pneumatic Postioning Switches are designed for manual operation of actuators requiring smooth gradual control and also for readjust ment of remotely located submaster instruments. They are 2% in, wide by 3% in. high and are compactly designed for panel board use. Powers Selector Switches are designed to deliver or stop or divert a flow of compressed air to selected control devices remotely located. Powers FLOWRITE Valves are used to control tbe flow of water or 4mm These valves are furnished with Powers #590 Teflon Graphited-Asbestos Packing. They arc available in single or doable seat and V-port types, direct or reverse acting --also in a three-way water mix type. Hot Water Supply. Temperature Controls--1 ' Shown here are a few of Powers complete line of seif operating and air operated controls for water heaters, heat exchangers, hot water line control, various types oi baths and processes. All are described; in POWERS WC CATALOG. No. 11 Self Operating Regulator controls temperature of liquids or air; operating temperatures from 60 to 260*F; sizes hi thru 4'; various types of valve bodies; available with 4" dial thermometer. Is widely used for water storage beaters; heat exchangers and processes. ACCRITEM Regulator is air operated; controls temperature of liquids or air; temperature ranges 50 to 250*F and 150 to 350*F. Used for water storage heaters, instantaneous heaters, heat exchang er^ submerged indirect heaters and processes. HYDROGUARD Thermostatic Water Mixers automatically blend hot and cold water to deliver a mixture at exact temperature desired. Used for hot water line control, various types of baths, and processes. Models available for various capacities and temperature ranges. Pneumatic Switches Accritem Regulator Type N Hydroguard *286 Controls and Instruments ^^ FULTON SYLPHON DIVISION Knoxville I, Tenn. Q Sales Representatives in Principal Cities For additional information, write for Product Bulletin listed in each product description SPACE HEATING CONTROLS Automatic - Radiator Valves #885 & #886 For exposed radiators and other heating units, either steam or hot water. Self-contained--no wiring, piping or auxiliary equip ment. Self-operated--continuously positions valve to maintain desired temperature. Packless, non-leaking valve. Quickly in stalled--simply insert in place of regular radiator valve. Ad justable. Self-powered valves also available for concealed radiation units. Sites % in. through 1 in. bulletin HVG-E. Automatic Radiator Valve for steam, #895 For any 2-pipe steam heating system of 15 lbs pressure or less. Suitable for convectors and enclosed radiators . . . only dial and adjustment knob are visible. Packless design. Two bulbs provide throttling action that assures very close temperature control. Minimum setting above freezing point. Control will lock at any adjustment to prevent tampering. Available in angle and globe types. Sizes in. through 1 in. Bulletin HVG-E. Radiator Valve # 522-A1 For hot water heating systems. Positive, accurate and reliable control of the flow of hot water. Used primarily on radiators or convectors to control room temperature in heating. Can' be applied to heating surfaces of induction units in some year ' round air conditioning systems to control room temperature for both heating and cooling. Sizes H >n- Only. Bulletin HVG-E. An electrically'operated valve for steam only. Suitable for pressures up to 15 lb. Used mainly for two-pipe steam heating systems . . for exposed or concealed radiators and unit heaters . . for control of individual rooms, zones, or entire buildings. A complete controlling unit'includes one or more #890 (angle type) or #891 (globe type) valves, a wail ther mostat and a simple transformer. Local or remote thermostatic control. Packless, no-leak valve. No wearing parts . . . nothing to lubricate. Sixes }4 in. through 1H in. Bulletin HVG-E. ' Temperature Regulator #7 . For unit heaters, wall or ceiling type radiators, steam-heated duct systems. Self-powered through filled bellows thermostat system. Packless valve continuously regulates steam supply according to setting on ultra-modern wall thermostat. 20F ranges up to 170F. Pressures to 75 psig. Sizes in. through 4 in. Bulletin HVG-E. PACKLESS EXPANSION JOINTS Sylphon* Packless Expansion Joints simplify building plans, save on the height of buildings, reduce cost of material and labor, and improve exterior and interior appearance. Successfully used in thousands of prominent build ings. Easy installation ... no repacking. They are made possible by the Sylphon Bellows, which makes these joints as permanent as other structural parts of the building. ' Low Pressure Type PACKLESS EXPANSION JOINT #1290 For steam or hot water lines. Simple, compact means of absorb ing expansion of "baseboard" radiation, finned convectors, supply lines, etc. Emergency packing feature gives extra pro tection and lengthens life should bellows ever leak: Comes completely assembled. Traverse: H in- Maximum working pres sure: 70 psig. Sizes in. through 2 in. Bulletin HVG-E. Kobertshxnc-Fullon Controls Co-, Fulton-Sylphnn. Dio. HEATING AND AIR CONDITIONING CONTROLS 287 Compensated Temperature Regulators #928 HI, -Jl, -Kl, -LI Low-cost single valve regulators that provide modulating con trol of heating and ventilating systems. Packfess valve modu lates steam flow according to dial setting on bulb. Control bulb automatically adjusts to prevent "droop" when constant dis charge temperature is wanted. Self-operated. Steam pressures up to 75 psig. Temperature ranges of 60F between 35T and 170*F. Sizes M in. through 2 in. Bulletin HVG-E. . Regulators #889-D&#889- Actually two self-powered regulators in one, providing highly advanced modulating action for duct systems. One bulb serves to regulate room temperature . . . the other the low-limit dis-' charge air temperature. A third bulb "compensates" for changes in demand, raising the "low-limit" setting if outside air temperature falls. Dial-type adjustment for.rangea between 35F and 170F. Bulletin HVG-E. Regulators # 889-F. aud #889-G These regulators provide the same multi ple control actions as #889-D and #889E. However, room temperature is main tained through an adjustable wall thermostat instead of a thermostatic bulb. Steam pressures to 15 psig. Ad justable temperature ranges between 35F and 170F. Bulletin HVG-E Room Thermostats #801 & 802 For heating, cooling or combination heating and cooling. Compact, attractive design. Available in Super Sensitive (#801) or Sensitive (#802) models. Suit able for direct control of many types of electric heating units, and for direct line voltage control of stokers, burners, mo - tors, pumps, air conditioners, fans, etc. Bulletin HVG-E - INDOOR-OUTDOOR CONTROL " FOR STEAM CONVERTORS i Regulator, # 928-PI This self-operated regulator varies hot ' water temperature as desired by regu lating steam supply to steam-liquid convertors. Outdoor bulb automatically resets control bulb, and increases water temperature as outdoor temperature falls. For steam pressure to 16 psig. Dialtype control bulb adjustable over any specified 60F range between 35F and 17CTF. BuLletin HVG-E CONTROL FOR MISCELLANEOUS USES Regulators # 1003 Series Completely self-powered, thesse sturdy units maintain hot water temperature by regulating flow of steam, to water heating units. Powerful, seamless Syl phon* Bellows actuates valve. Available with direct-or reverse-acting valve or 3 way valve. Adjustable temperature ranges between minus 35F and plus 455F. Bulletin HVG-E PACKLESS EXPANSION JOINTS High Pressure Type PACKLESS EXPANSION JOINT #1291 For steam or water lines--vertical or horizontal. Internally guided stainless steel multi-ply Sylphon Bellows. Completely assembled ready for easy installation. Traverse: 2 in. (also available to give 4 in. traverse). Maximum working pressure: steam 125 psig; water 150 psig. Sizes % in. through 3 in. bul letin HVG-E. `. PACKLESS EXPANSION . JOINTS #110-M and #I11-M These simple, rugged units absorb up to 1-H in. movement in horizontal or vertical lines. Two-ply Monel bellows will not corrode or leak at pressures up to 100 psig. No. 110-M, shown on opposite page, is for steam lines; No. 111-M is for water service. Sizes from % in. through 3 in. Bulletin HVG-E.  288 Controls and Instruments Ct4tCO //VCOj9/,O/Z47E0 Columbus i, ohio REFRIGERATION AND AIR CONDITIONING CONTROLS "0" type Commercial Refrigeration Controls, in Single or Dual Types adaptable to temperature or pressure operation; automatic cycle or manual reset. Single pole, single throw or single pole, double throw switches with front access terminals. Temperature range adjustment: --37*F to 110*F. Adjustable differential: 5* to 20*. Pressure range adjustment- 20 in. vac. to 450 psi. Adjustable differ-' ential: 5 to 25 psi and 30 to 100 psi. "G" type Commercial Air Conditioning and Refrigeration Controls for low and high pressure ap plication. non-adjustable in the field. Small in size, readily adaptable to panels. Screw or quick-connect type terminals. With or without manual reset on either single or dual pressures in combinations.. Electrical Ratings from Pilot Duty through 18 amp., full load. *`C17" Air Conditioning Control for automatic changeover on heat pumps or two-stage cooling dr heating operation that features two electrically separate, switches operated by one temperature-sensitive power element Liquid filled power element controls from the bulb. Switches are single pole, double throw with quick-connect type terminals. "A10" type Refrigeration Controls for use on household refrigerators, freezers, beverage coolers, water coolers, window air conditioners, etc. Single pole, single throw switch. 15* to 35* dial range from --37*F to 95*F. Differential: 5* to 24*. "F17" Air Conditioning Control is a cycling tem perature type plus an auxiliary switch built-in for fan opera tion. Dial knob operates and controls both fan artd unit Switches are single pole, single throw. Maximum range of 25*F. Control differential: 4*F. "V25/26" Instant Reversing Solenoid Valves for unit air conditioning heat pump systems to reverse the flow of refrigerant for either cooling or heating or both without an "off" period. Capacity of V25 is 2'A through 7lA tons; of V26 is 1 through 2 tons using Refrigerant 212. Ranco Also Manufactures Motor Relays. De-Icing Controls, Clothes Dryer Controls, Automatic Defrost Timer Controls. Sequence Timers and Automobile Water Heater Modulating Valves. Write for descriptive literature. - Controls and Instruments 289 SPENCE ENGINEERING COMPANY, Owners of Rider-Ericsson Engine Co., Founded by Capt. John Ericsson IS42 * 31 Grant St., Walden,. N, Y. . Automatic Regulating Valves, Desuperheaters and Strainers Offices in alt Principal Cities INC. SPENCE AUTOMATIC REGULATING VALVES One or more separate, sensitive pilots control the main valve in Spence Regu lators. These pilots are connected to the main valve by means of unions. This Spence feature offers the following ad- (1) It's easier to inspect and maintain Spence Regulators. . (2) It'* simple to change the control function of a Spence Regulator by changing the pilot. All main valves, re gardless of size, can be controlled by a wide variety of Spence pilots. (3) It assure* that you get the most effective and economical regulator for your needs because of the many possible combinations of main valves and pilots. Type E Main Valve The illustration at right shows how a single main valve is combined with two pilots to form two different regulators. .... TypeD Pressure Pilot TYPICAL SPENCE PILOTS - Type D Pressure Pilot --for reductions to between 3 and 150 psi . Type N Differential Pilot--for differential pressures between 3 and 150 psi Type ET124 Temper ature Regulator Type ED Pressure Regulator Type T124 Pilot--for heater pressures to 50 psi Type MQ-- Combined Electric -and Pressure Pilot--a pressure regu lator cut on or off elec trically -- Type T14D Tempera ture Pilot--for heater pressures over 50 psi Type P14 Pump Gov ernor Pilot--closes on a rise in pressure con nected to its dia- ' phragm Type O^Back Pressure Pilot--for back pres - sures between 3 and 150 psi Type X2 Liquid Level Pilot--float control for open tanks -A FEW SPENCE MAIN VALVES- For accurate water pressure reg- Type E2 Main Valve for ulation--Type D24 Direct Acting low initial pressures and Water Pressure Reducing Valve low differentials Type E3 Main Valve for high initial pressures and low differentials Type C2Q Main Valve same as Type E but double seated  290 Controls and instruments WH ITE-RODGI C O M RAN 1209 Cass Ave., St. Louis 6, Mo. New York, N. Y. (Long Island City) Buffalo, N. Y. Atlanta, Ga. In Canada, Wbite-Rodger* Limited, Toronto Chicago, III. ' Detroit, Mich. Los Angeles, Calif. Distributors in Principal Cities RS Cleveland, Ohio Philadelphia, Pa. (Havertown) Columbus, Ohio HYDRAULIC-ACTION CONTROLS The complete line of White-Rodgers controls includes: Warm Air Controls Relays Low Voltage Thermostats Gas Valves Line Voltage Thermostats Oil Burner Controls Hot Water and Steam Controls Refrigeration and Air-Conditioning ' Controls Hydraulic-Action temperature controls operate on the * principle of expansion and contraction of a solid liquid charge against & diaphragm. This system, developed and perfected by White- Rodgers provides accuracy comparable to that of a fine thermometer . . . and other outstanding features guaranteeing excellent performance. - ADVANTAGES OF HYDRAULIC-ACTION Hydraulic-Action controls provide maximum sensi tivity--positive dial settings--full range accuracy-- consistent differentials--eliminates temperature drift- simplified installation--extra sturdy switch mecha nism--and other qualities that assure long satisfactory operation. ' "Fashion" Ther mostat, low voltage, shown with hinged cover partly open. Pleasing shape - blends with any room decor. Adobe .Beige finish. Bi metal operation. Push Button sub base using "Fash ion" thermostat to give finger-touch selection of heat ing, air-condition ing or off. HOT WATER ZONE CONTROL PACKAGE Low cost system which uses no flow valves and after first zone no additional relays or circulators are neces sary. Low voltage wiring. Uses common return to save on piping, fittings etc. PRIMARY CONTROLS In addition to Hydraulic-Action Controls, WhiteRodgers manufactures Oil Burner primary controls, Gas Valves (both diaphragm and solenoid types) and automatic pilots for gas installations. Line voltage ther- JUSi 0*'ir ditioning installa. tions.. ' Zone Valve. Quite automatic water valve for inexpen sive zoning of Mo tels, Hotels, SplitLevel ; ' Homes, Ranch-type homes. Dual Hot . Water Controls; Limit and Circulator; High nil Low Limit combinations. Also made in single con trols. . Fan and Limit con trols in single Qpse. ' Note the flexible elements. Also: in single units. Remote bulb heavyduty thermostat, also availabe with self-contained bulbs. Oil Burner primarycontrol (stack switch). - Intermi t-, tent or Constant . Ignition types. "Cushioned Power'* - Solenoid Gas Valves- Quiet, . soft seat, - spring loaded, for ALL gases. - Contact your nearest White-Rodgers office for complete information. Catalog and Engineering data fur nished quickly/ .' Controls and instruments 1001 Newark Ave., Elizabeth, NJ. In Canada: Wilcolator (Canada) Ltd., 221 Evans Ave^ Toronto 14, OnL Export Address: Wilcolator, 1010 Schaff Bldg., 1505 Race Su, Philadelphia 2, Pa, THE New Effective- Temperature Control The Wilcolator G2-E Effective-Temperature Control is a thermostat designed to sense both dry bulb and wet bulb temperatures and to combine these signals in such a way that the thermostat controls at any selected effective temperature. In application, a wick or sleeve surrounding the wet bulb cools it by evaporation of the water supplied from the evaporator. As humidity increases, evap orative cooling decreases, and temperature of the wet bulb rises. Hence an increase in . humidity appears to the thermostat as an ' increase in temperature, just as-it does to the human body. Volume of the wet bulb is so proportioned to volume of the dry bulb that the thermostat automatically corrects the controlled temperature to compensate for changes in humidity. 291 TYPE G2-E Thermostat with Positive''Off" or "Constant Cool" The Wilcolator Type G liquid expansion electric thermostat features an improved, snap-action, vibration-proof control mecha nism permitting much higher ratings than previously available is such a compact unit *' (2% x 1% x 1% in.). Suggested applications . include room coolers, space heaters, and air- . conditioners. Ratings are the same as for' Type GA. Standard temperature range for . both Q and GA controls is 0*F minimum; 5S5F maximum. Special temperature ranges to customer's requirements. The Wilcolator GA is a versatile new ther mostat for both cooling and beating* appli cations. Higher rated lor new heavy duty appliances, it consists of a standard Type G thermostat, plus a special switch--cam op erated by the dial shaft--permitting control of several circuits with a single dial/Contact rating, heater load (Type Gl-A): 30 amp, 125 and 250 v a-c noninauctive load. Cooler ratings (Type G2-A): 120,208 and 240 v a-c; running current--14 amp; locked rotor--60 amp.'  292 Controls and Instruments, Combustion Field Control Division H. D. Conkey & Company, Mendota, 111. Field Barometric Draft Controls Field M+MC2s A Three-Fuel Control, in Sizes 10 in. through 32 in., for Oil, Oil-Gas, Gas, and Coal Fired Furnaces and Boilers.' The M+MG2 will serve gas, oil or coal with equal efficiency, and requires only minor, in-the-field changes to adjust from one fuel to another. A plant might conT vert from coal, to oil, to gas, then to oil-gas, without obsoleting this control. With coal it serves as a combi nation barometric draft control and check damper. With oil it serves as a single-acting barometric control. With gas it becomes a double-acting control, opening inward to regulate up-drafts, opening outward to re lieve down-drafts. Where gas-oil is used interchange ably, the control change takes less than a minute. The Field M+MG2 is a specialized, precisionmade, three-fuel control. Because, it is a control of extreme sensitivity, it is, of necessity, a control of extreme structural strength. For example, accuracy is increased when the clearance between a ring and gate is held to a minimum. To permit this, in the M+MG2, without risk of binding, Field developed a die-formed, heavy gage ring. Its deflection strength exceeds many fold the normal requirements of shipping, installation or use. The gate is also very heavy--39 pounds for a 32^inch control. Such weight obviously provides ex treme rigidity. Heavy weight is also, paradoxically, a requirement of the virtually friction-free gate mount ing that gives the M+MG2 its extreme sensitivity. Only a heavy gate could be so delicately balanced. The same weight factor also prevents the spurious responses to which so sensitive a gate might normally be subject. The M+MG2 gate is mounted on a long, thin, stainless steel knife edge, which in turn rests on self aligning bearings. The bearings are self-cleaning. Soot dr dirt cannot accumulate to cause binding or friction. They are also Belf-leveling--assuring that the knife edge is always in contact across the full width of the bearing, for an even distribution of weight. When the gate moves, only the sharp corner of the knife edge rests on the bearings--an area of contact so minute that friction is virtually non-existaat. The result is extreme and instantaneous sensitivity to draft change. The gate is deeply recessed in the ring, to direct the flow of air over the gate and avoid response to random, variable air conditions outside the control. The M+MG2 permits an unusually wide range of draft settings. The 18 in. control, for example, will maintain a draft setting as low as 0.002 in. The same control will maintain a draft as high as 0.3 in., a re quirement where there is a very high draft loss through the appliance. Compensation for differences between horizontal and vertical installation is fully provided, by the simplest means available on any Field control. Where a safety switch must be specified, to meet gas code requirements, attachment is easily, effectively, and compactly made. Compactness is a characteristic of the M+MG2. There are no protruding parts. Even the stainless steel bead chain is short, holding setting weights neatly against the side of the control. ' Unless otherwise specified the M+MG2 control is shipped as a single acting control, with patterned collar. For gas, the installer will set control for double-action. If solid fuel is involved, order the M+MG2 Barochek. If control is to be shipped less collar, so specify. . Controls and Instruments, Combustion Field Control Division 293 Control Sa 10 12 14 16 11 20 24 20 32 Mondial W Reecn. Pipe Sizes - PHYSICAL DATA B C D E F G H J Kl M y. n\ 715 113 154 ZUI 2 J14 452 lb 804 9 ( 10 2014 to 3114 10 4)4 10 414 11 3)4 1V4 4)4 1 3** j l&t 9%# M* 11112 14fc to 37% 12 5% 12 5 1314 4H 1* 4)4 1 314 V 2214 1114 0 8V4 13(14 ttttto 44 14 714 14 5)4 1514 5H 214 514 1 314 )4 2614 17* 11* 15 1 16 47 to 50V4 IS 6% 16 $M 17V4 6)4 2)4 5)4 1M 4 H 30 20* 17 t 10 53)4 to 56M 10 014 10 7)4 19)4 6)4 2)4 7)4 1M 5V4 1)4 33)4 34 * 17)4* 22)4* 18 to 21 0)4 to 2D 8% 20 614 22 7H 3 7)4 114 614 114 37)4 4214* 28V4* 22 to 2S 69 to 78V4 24 12)4 24 1014 26 9143H6K2 614 114 4^4 65* 44* Into30 01)4 to 9414 21 1314 29 38!A 10)4 414 11H 2 614 54 52M 95 * 69 * 31 to 34 9714 to 107 32 15)4 32 35 1214 4)4 12)4 2 $14 V4 9314 123* OS* .T6 .45 02 ~7D 2.12 IJJ3 11 1.41 198 2JB 5AS 190 711 445 7J0 740 SWITCHES: A draft hood provides relief for down draft pressures, but gives no visual sign of spillage. The double-acting M+MG2 gate opens outward to relieve such pressures, and by its position signals any spillage. In addition, the M+MG2 can be equipped with an automatic switch where the engineer finds conditions which could create frequent and pro longed down drafts. A time delay switch is usually recommended for an atmospheric burner; a thermal switch for a power burner. These switches provide an obvious means to measure the extent of a down draft problem so that an engineer can judge if and when some remedial action is indi cated. H + BIC2 Doable Acting for Gas, opens Inward to regulate op drafts, and opens ontward.to relieve internal pressures M -f MG2 Single Acting for Oil M + MG2 Barochek for Solid Fuels FIELD TYPE M: For automatic heating equipment, designed to as sure finer performance, greater fuel economy, through highly accurate : control of drafts. Available in sizes from 6 in. through 9 in. for pipe di ameters of 5 in. through 10 in. Fea tures "Hocking Chair" gate action, off-center gate mounting, sidewings, extended housing. Widely used in the heating industry. ' FIELD TYPE RC: Calibrated draft control in sizes 6 in. through 9 in. for 5 in. through 10 in. flues. Features extreme capacity, and re versible wing flap on gate for more precise adaption to either vertical, horizontal or sloping flues. Friction- free gate mounting, single strap at taching, easily leveled on a sloping flue. FIELD MGI: Double-acting con trol for lower-input gas-fired, fur naces and boilers; widely, used in conversion burner installations. Opens outward to relieve down drafts; opens inward to regulate up drafts. Sizes 7 and 8 In. for 6 through 8 in. flues.  294 Controls and Instruments, Combustion COMBUSTION CONTROL DIVISION Electronics Corporation of America One Memorial Drive Cambridge 42, Mass. FACTORY SALES OFFICES Cambridge, Mass. Charlotte, N. C. Chicago, 111. Cleveland, Ohio Hartford, Conn. Houston, Tex. New York, N. Y. Philadelphia, Pa. San Francisco, Calif. St. Louis, Mo. Washington, D..C. Toronto, Ontario ECA (Canada) Ltd. Albany, N. Y. Albuquerque, N. M. Amarillo, Tex. Atlanta, Ga. Baltimore, Md. Birmingham, Ala. Buffalo, N. Y. Charlotte, N.C. Cincinnati, Ohio Cleveland, Ohio Dallas, Tex. Denver, Colo. Des Moines, Iowa DISTRICT SALES OFFICES Detroit, Mich. El Paso, Tex. Houston, Tex. Indianapolis, Ind. Kansas City, Mo. Kingsport, Tenn. Loo Angeles, Calif. Memphis, Tenn. Milwaukee, Wise. Minneapolis, Minn. New Orleans, La. Odessa, Tex. Omaha, Neb. Phoenix, Ari*. Pittsburgh, Pa. Portland, Ore. Richmond, Va. Rochester, N. Y. St. Louis, Mo. Salt Lake City, Utah Seattle, Wash. . Shreveport, La. Spokane, Wash. Tampa, Fla. Tulsa, Okla. Washington, D. C. FIREYE SAFETY INTERLOCK SYS TEMS FOR SEMIAUTOMATICAIAY AND MANUALLY-LIGHTED BURNERS. Complete safeguard systems for up to four burners per boiler--oil, gas, or combination oil-gas. Assures safe light-off and firing..Includes System FP-4 elec tronic control in pre-wired cabinet assembly; plus all external valves, switches, and alarms. FIREYE ELECTRONIC SAFEGUARDS AND PRIMARY CONTROLS. System FP-2. Flame failure protection and program ming for automatic industrial oil, gas, and combina tion oil-gas burners, UL-FM approved. System FJ-2. Flame failure protection and program ming for automatic commercial light oil, gas, and combination light oil-gas burners. UL-FM approved. System FP-4. Flame failure protection for semiautomatically and manually-lighted oil, gas, and combina tion oil-gas burners. UL-FM approved. FIREYE VALVES AND INTERLOCKS. Oil Valves. Manual reset or solenoid operated safety' shutoff valves for all oil burner applications. Gas Valves. Automatic or manual reset types, 1 in. to 6 in. IK. Solenoid operated pilot gas valves, % in-, and lA in. IPS. Supervisory FM Cock, manually operated, lubricated plug cock. Untamperable position: indicating switch. - FIREYE PHOTOELECTRIC SMOKE DENSITY INDICATOR. System FES. Provides low cost, easy-to-instal) smoke density indication with assured accurate readings. Helps keep smoke within legal limits. Saves fuel dollars. Chart recorders also available. Light Source Controls and Instruments. Combustion 295 SIMPLEX MANUFACTURING COMPANY 198-206 North Main Street Fond du Lac, Wisconsin . SIM--TROL Barometric Draft Controls--Types "A" "C" "F" "H-HG" Breechings and stacks must provide sufficient draft under adverse atmospheric conditions. During normal and high barometric periods, cold months, and windy days, excessive draft intensities are generated with resulting inefficiency and fuel waste. - ADVANTAGES SIM-TROLB automatically maintain the predetermined minimum draft required for good combustion, fuel economy, increased heat transfer, by reduction of gas velocity through the boiler or furnace bonnet, minimising cold air infiltration and inrush causing sudden shrinkage of boiler parts. They eliminate local hot spots, floating and pulsating flame and sucking out of pilots. They im prove feed water regulation, super-heater results, boiler-life.and boiler-room ventilation. SIM-TROLS aid materially in smoke abatement and boiler cleanliness by reduction of unburned combustibles and air dilution of stack gases. Lowered stack temperatures prolong liner life and reduce fire hazards. CONSTRUCTION SIM-TROLS, properly sised, adjust easily to any desired draft intensity. The races of the Type A SIM-TROL adjust laterally, the race assembly vertically, and the arm angle may be varied in re- lation to the plane of the gate. . racfL* Type C SIM-TROL adjust laterally, the assembly vertically, but the angle in relation to the gate is not variable. Gates of Type A and Type C SIM-TROLS rotate on cold rolled arbors and prelubricated dust proof ball bearings. Curved tubular counter-balances contain metal balls which constantly change position to compensate for varying rotation angles of the gate maintaming overfire draft within 0.01 in. water, plus or minus. Gates of Type F SIM-TROLS rotate on cold roiled arbors and dust proof ball bearings in sices from 12 in. x 12 in. upward. Ad justable weights hung on slide loops permit regulation along the curved slide arms. Gates of Type H-HG SIM-TROLS rotate on heavy gage black oil tempered wire extending into drilled holes in the metal frame of the control at an off-center horisontal point. Counterbalance members are similar to that of the Type F, except as to angle of application. SIM-TROLS are protected by hard, beat resisting boiler room enamels. All counter balance members are outside, free from corrosion and encrustment by products of com bustion. Type "A" SIM-TROL DESIGN FACTORS Sizing is important. The input opening should equal the stack area, plus 10 percent for each 35 ft of stack over 65 ft thereof. Preference should be given to control width, rather than for height, for ease of adjustment and smooth gate rotation. Horizontal clearance from installation point approximates gate height plus 30 in. Oyer-all height approximates gate height plus 37 m. Over-ell width approximates gate width plus 8 in. Designs for limited space may be made if plans are submitted. SIM-TROLS of types A, C and F are individually designed to plant specifications, including breeching and stack dimensions, clearances, fuel, method of firing and num ber of boilers on the line. Detailed sketches are submitted for approval or suggested change without obligation. SIM-TROLS--Types A, Fand H-HG are designed to serve plants fired with solid, liquid or gaseous fuels under any method of firing. An adjustable "stop" is provided above the gate to allow dual gate action when used in connection with gaseous fuel, the stop being turned upward. For use with solid or liquid fuels the stop is turned downward effecting single action required for those fuels. Full capacity ana efficiency are available for both draft control and relief of back pressure from any cause. The Type C SIM-TROL is not adaptable to dual gate action, though it is efficient in connection with powered gas burners, or plants using induced draft equipment, or Jtlants fired with solid or liquid fuels. We do not recommend the Type C SIM-TROL or plants burning gas and designed as purely atmospheric type. - Type "F" SIM-TROL Type "H-HG" SIM-TROL Type "C" SIM-TROL *296 ENGINEERED PRODUCTS Expansion Joints f^^sJEeuuL ADSCO DIVISION Yuba Consolidated Industries, Inc. * 20 MILBURN ST. BUFFALO 12, N. Y. Yuba Plants and Sales Offices Nationwide ADSCO CORRUFLEX PACKLESS EXPANSION JOINTS Equalizing, Welding Ends Adseo's Corruflex packless expansion joints absorb pipe expansion and are adaptable to any piping condition. The equalising joint is used for various types of motions and is suitable for pressures to 300 psi and higher. They are made in sixes ranging from 3 in. to 54 in., with single or multiple corrugations, with flanged as well as welding ends. They can be supplied with covers and telescoping inner sleeves. * Non-Equalizing, Flanged Ends This type is generally used to absorb small amounts of expansion and to iso late vibration under vacuum or pressures to 50 psi. Depending on the metal used in the expansion element, both the equaliz ing and non-equalizing types are suitable for temperatures from sub zero to 1600 F. Adsco also manufactures a close-pitch type and a semi-equalizing type with root rings to reinforce the corrugations. Special Types Special types of Adsco Corruflex ex pansion joints, like the pressure-bal anced above, can be designed and manufactured to absorb axial, lateral, or angular rotation, or any combination of these movements. Some of these special types of expansion joints are the universal, hinge, swing, gimbal, tie-rod, and internally-guided. Consult Adsco for details on the performance of these special expansion joints in pipe lines. ADSCO SLIP-TYPE EXPANSION JOINTS "PG" Joint, Flanged Ends Slip-type expansion joints, designed for axial motion, offer long traverse, low initial cost, and produce minimum stresses on pipe anchors. The pistoo-ring joint, Tvpe "PG", can be unpacked ana repacked under full line pressure because of its piston-ring feature. The polished, chrome-plated sup cannot be scored by metal-to-metal contact. Packing can be quickly lubricated. In the externally- internally guided piston-ring joint the slip is fully supported at both ends throughout its circumference over the entire length of travel. .. "P" Joint, Welding Ends The internally-guided piston-ring joint. Type "P", being more compact, is especially recommended for use where space is limited. This unit, like the "PG" Type, can also be unpacked and repacked under full line pressure. Adsco slip joints are furnished in both single and double units with flanged ends or welding ends. Sizes range from 1* in. up, with traverse per slip from 4 in. to 12 in. Semi-steel joints can be used for working pressures to 250 lb and temperatures to 450 F. Steel. joints can be used for working pressures to 400 lb and temperatures to 800 F. ADSCO STANDARD HEATERS Pipe Alignment Guides . ; Proper guiding of a pipe line, as ob tained by Adsco pipe alignment guides, is essential to insure straight axial move ment of the pipe to the expansion joint. Misalignment may damage equipment. A pipe line should be considered as a load bearing column and pipe alignment guides should be used accordingly to prevent bowing and bending. Pipe sup- ports such as hangers, chairs, or rollers are not to be considered as guides. Write for details on the latset designs in Adsco pipe alignment guides. Storage Water Heaters Adsco storage heaters are built in accordance with the ASMB code * for working pressures desired. Tanks are made of flange-quality steel, nickel-clad or stainless-clad steel, or copper silicon alloy. Where alloy tanks are used, tube sheets are of corrosion-resisting metal, so that service water does not come in contact with any ferrous parts. Steel tunIra can be lined with all standard linings, including Adsco Pheoolic 6-2 or Adscote bitumastie to prevent- cor rosion. Heatingelement iseasily temeved . for cleaning. ' Instantaneous Heaters . Adsco instantaneous heaters are made in a large variety of types, including the simple U-bend instantaneous shown above, which is used to heat water for showers, dishwashers, laundries, and other purposes. These heaters are also used as converters for furnishing hot water to space heating systems.. Many straight-tube, float-bead units are used as closed feed-water heaters, boiler blow down heaters, and for various uses in the process industries. Oil Pre-heaters Adsco oil pre-heaters help obtain highly efficient performance from fuel oil by heating it properly for complete combustion in the burner. In many cases, the work done by oil pre-heaters permits the us of heavier grade, less costly fuel oil. These heaters frequently are used with Adsco tank suction heaters, the two units making an efficient team. Tank suction heaters, which heat only the liquid to be pumped and not the full contents of the tank, also are available. I Expansion Joints 297 Flexoitics Corporation EXPANSION JOINT DIVISION 1329 South Third Avenue Maywood, Illinois Factories and Warehouses: Detroit, Mich.; Maywood, Elgin, Rock Falls, and Savanna, 111.; Memphis, Term.; Santa Ana, Calif.; Elizabeth, N. J. District Offices Atlanta Boston Cincinnati Cleveland Detroit- Ft. Worth Kansas Citt Bos Angeles Memphis Milwaukee New York Philadelphia San Francisco . In Canada: Flexonics Corporation op Canada, Ltd., Brampton, Ontario FLEXONICS EXPANSION COMPENSATORS FOR STEAM AND HOT WATER HEATING SYSTEMS Model L-for pressures to 60 psig The Flexonics Model L Expansion Compensator consists of a two ply phosphor bronze bellows with copper tube end connections enclosed in a protective shroud of brass. It is especially designed for control of expansion in finned type convectors, baseboard, radia tor or heating supply and return lines. Sizes from V< in. through 2 in. Suitable for tempera tures from --60 F to 250 F and for pressures up to 60 psig. A single unit will handle motion up to Vs in. (Vt in. compression, V% in. extension). Available with all commonly used fittings. Model H Cor pressures to 175 psig . The Flexonics Model H Expansion Compensator is used primarily on vertical risers for high pressure steam and hot water lines. However it may also be used on horizontal runs. The Model H consists of a cor rosion resistant Flexonics Bellows enclosed in an allwelded steel housing. The unit is provided with a posi tive anti-torque device to prevent possible bellows damage during installation. Sizes from SA in. through 3 in. Suitable for tempera tures from --60 F to 750 F. Maximum test pressures 50 psi over working pressures shown in table. A single unit will handle motion up to 15A in. (1Vi in. compres sion, XA in. extension), Mild steel male NPT pipe nip ples on both ends are standard. Ground joint unions or weld ends are optional. Sizes and Dimensions Tube Sue (tnj Overall Length, in. Sweet Eads Female Threaded Ends - Max. O. D., in. Female Eads K 8X IK 6*6 IK 7 10$, m 2* iK 7*Kt 2K 2 SK 10K 3 1* 1* 2* 2K 3 Sizes and Dimensions Pipe Sue On.) O/A Length (in.) Mas. O. D. (in.) Working Press (pai) Unit Wt (1b.) Hm 1 9* IK 13* i* 13* 2 12* 2* 13* 3 14**6 2H 2K 3* 3K 4U 5 5K 175 2.6 175 2.8 150 7.7 150 8.0 125 10.3 125 13.7 125 17.4 FLEXONICS EXPANSION JOINTS FOR POWER AND PROCESS PIPING For medium and high pressure piping, Flexonics offers a complete line of corrugated expansion joints in free-flexing and controlled flexing types. Free-flexing units are available in standard sizes from 3 in. to 48 in. ID, for pressures to 30 psi, temperatures to 850 F. Designed for expansion travel up to 3Va in. per unit. Controlled-flexing units are available in standard sizes from 3 in- to 48 in. ID, for pressures to 300 psi, tem peratures to 850 F. Designed for expansion travel up to 7Vi in. per unit. Both free-flexing and controlled flexing types are available with flanged or welding ends.  298 Expansion. Joints U. S. Flexible Metallic Tubing Co. Since 1905 . KEFLEX MANUFACTURING DIVISION General Offices--63 Main St., San Francisco 5, Calif. Factory--Los Angeles - Sales Offices--Agents in Principal Cities of United States and Canada TYPE 1 O WITH BRASS FEMALE THREADED ENDS Working Pres. 390 PSI Maximum Trap, toe r KEFLEX QUADRA-SIDE EXPANSION COMPENSATORS FOR STEAM AND HOT WATER HEATING SYSTEMS KEFLEX Type 7 Q and 7Q-T packless type, expansion compensators are designed to compensate for both expansion and contraction in low or high temperature heat ing supply lines as well as for fin tube baseboard radiators and convectors. Type 7 Q has square brass ends with female tapered pipe threads. Type 7Q-T has female copper tube ends for soldering to copper pipe. TYPE 70-T WITH COPPER TUBE ENDS Maximum Pm. PSI Maximum Temp, m 9 The bellows section, made from highly flexible, multi-ply (two or more plies), Type 321 or 347 stabilised stainless steel, is protected from torsion, squirm, misalignment,' and external damage by a square, brass, telescoping case having positive stops against over compression. To Fit Copper Tobins Nominal Actual IX). O.D. *' .if 1 IK m mm im w 3H lm Overall Length 8.60*. 9.50 9.60 9.00 10.00 10.75 11.50 Max. 3.00* 3.00 3.00 3.50 3.00 3.50 4.00 m m m. 3H 4H 5K 8X TYPE UO-T WITH COPPER TUBE ENDS Maximum Pres. 109 PSI Maximum Temp. IMF To Fit Copper Tobias Normal ID. Actual OD. K' 1 .If IK m 3. m m IVi Overall L",tt 4.50* 4.50 4.50 4.60 4.60 Max- 1.50* 1.60 1.75 3.35 3.75 WL f IK ;IK 4 TYPE QAB ANCHOR BASE ONLY ' The force to compress KEFLEX Quadra-Side Compensators is less than 100 lb; Standard units will accommodate a total traverse of 2 in.; IX in. in compression and X in. in extension. Units for traverse in compression of in., 2 in. and 3 in. are available with proportionate extension. Made in sites % in. through 3 in. All KEFLEX Quadra-Side Compensators are provided with a removable screw, set for the indicated traverse in compression. KEFLEX TYPE 11Q-T QUADRA-SIDE EXPANSION COMPENSATORS USED WITH CONVECTOR AND FIN TUBE BASEBOARD RADIATION UNITS IN SCHOOLS, HOSPITALS, OFFICES AND COMMERCIAL INSTALLATIONS KEFLEX Type 11Q-T, packless type, expansion compensators are designed for use in low pressure heating systems where maximum test pressures do not exceed ISO psig. They will compensate for expansion In compression up to ^ in. and % in. in extension--a total traverse to 1 in. The bellows section, mad from Type 321 or 347 stainless steel, is enclosed in a'square brass case which elides over a square guide to provide positive protection against torsion, squirm and external damage during installation. Sixes: % in., 1 in., Ij in., in. and 2 in. Maximum Working Pressure 100 psig. Maximum Tem- ` per&ture 300 F. KEFLEX TYPE QAB INTERMEDIATE ANCHOR BRACKET Type QAB is a heavy bronze bracket for use with KEFLEX Type 7 Q Dual Expan sion Compensators as an Intermediate Anchor. The bracket is provided with two holes to facilitate attaching to floor, wall or ceiling. A set screw cinches the bracket tightly to the 7 Q unit and limits the movement to each individual compensator. Suggested for use in long runs of fin tube piping where lines should be segmented between the main.anchors. .1 ' 1 SESSTc^T ` V- -S'* Flexible Metallic Tubing Ceu, Keflex Mfg. Div. ' 299 KEFLEX VIBRATION ABSORBERS The high flexibility of KEFLEX Vibration Absorbers makes them extremely suitable to absorb vibration from pumps, chillers, and compressors. Keflex Vibration Absorbers are packless type as they have a bellows made from laminated stainless steel, type Ml At S47. .^ They may also be used as tow pressure expansion joints f75 psig) where axial movements of H in. in compression and H in. in extension are desired. A lateral movement of in. is also obtainable. The close face to face or overall length measurement permits their use in very close quarters where longer lengths of flexible hose would be impracticable. KEFLEX Type 301 Vibration Ahsorbers ore designed for higher pressure service than Type 151, or Type 71. Reinforcements have been added to withstood pressures over 150 psig. A liner is not standard equipment but is available if required. Dual units with long spacer nipple for lateral movement or correction of misalignment are furnished to specification. ` . Type 7i-21V.is fitted with carbon steel mechanical flanges having special elongated . . bolt holes on senes 15 bolt circle. Keflex reattachable flanges may be applied Jobsite in making emergency repairs. ~ Type 151 is fitted with either carbon steel weld ends or 150 lb type rigid flanges having special elongated bolt holes on a series 15 bolt circle to permit easy installation. ^ Type 301 is furnished with either carbon steel weld ends or 150 lb type lap joint flanges; 300 lb type flanges are also available. 71-21V ' TYPE Overall Length Sixes **-2H*-3* . Sixes 3H*-48* Inc. Max. Work Press, psig Max. Temperature Fahr. . Traverae Compression Extension Lateral Deflection 71.21V 4.75* 4.75* 73 800 0.50* 0.135* 0.1S5* ISi-JV 11.00* 11.00* 150 .-.800 ___- 0.60* ' 0.126* 0.125* 301-2V 301-14V : 301-4-14V (braided) 1S1-I2V 4.75* 4.75' 150 800 ' 0.60* 0.125* 0.125* 301-2V 11.00* 11.00* 300 800 0.50* 0.135* ' 0.135* i0l-l4V 11.00* 11.00* 300 800 0.50* 0.125* 0.125* U.S. FLEX FLEXIBLE CONNECTORS .' BRONZE METAL nOSE with High Tensile Bronze Braid - - Install as near to pump as possible in each suction and discharge line for chilled water, hot water, steam, - and force pump systems. FLEXIBLE "BMH" Connectors' BMHN---IPT Nipples Brazed on. BMHF--125# Cast Iron.Flanges Threaded on Nippies. . Suggested Lengths for Average Installations: Appro*. Offset Motion Intermit. Permanent DAMPEN NOISE PREVENT . PIPE LEAKAGE W VIBRATION ' CORRECT MISALIGNMENT "USF" BRONZE VIBRATION ABSORBERS WITH COPPER TUBE ENDS  300 U. S. Flexible Metallic Tubing Co., Keflex Mfg. Die. Expansion Joints ' KEFLEX EXPANSION JOINTS Corrugated, Packless Type FOR STEAM AND HOT WATER HEATING SYSTEMS AND PROCESS PIPING KEFLEX packless type Expansion Joints are made from highly flexible laminations of Type 321 or 347 stabilized stainless steel. Standard equipment in both KEFLEX Types 158 and 308 consists of a packless type, stainless steel bellows; weld ends or carbon eteei flanges; self guiding, full bore, flow liner; and self equalising contour control rings in sixes over 4 in., also available for smaller siaea- Type 308 also has reinforcing shoulder rings. Sires 2 in. through 48 in. The force to compress KEFLEX Expansion Joints is usually less than 100 lb. ' 138-9E . 158-15-9E 1S8-12E 158-IS-12E Rigid flanges supplied on standard Types 158-12E and 15S-15-12E assemblies have a series 15 drilling, but with special elongated bolt holes to permit easy installation in the event companion flange bolt holes are misaligned. Overall Length Sixer Size* IneL . KziiMB Working Pressure img utfnw. Temperature Fattr. Traverse Compression gviwaiim 15S-9B 12.00* 13.00' 150 800 2.00' 0.60* ' lSA-lS-9k 19.7$* lt.ty 150 800 4.00r 1.00' 15S-IZE 7.IS* 6.75* ISO 800 J-00' 0.50' IJ8-I5-11E 14.00* U.00' ISO 800 4.00* 1.00* " 308-9E 303-1S-9E 308-14E 308-15-14E When flanges are required, Type 308 is fitted with lap joint or swivel flanges. ISO lb type is standard; 300 lb type and heavier are available. 30S-9E 308-144E 30&-14E Overall Length Sbm Sixes W-H*. tod. ^fw4rr.rerei Working pTeSSUT* pSIg Wziinton Tempemlun Fahr. Trareme Cuuipmsrinn lMhiwina 14.SO* 14.00* 800 900 8.00* 0.50* .oo* 22.00* 800 800 4.00* 1.00* 14.80* 14.00* 800 800 1.00* o.so* 83.00* . 18.00* 800 800 4i..o0o0r' KEFLEX ANCHOR BASE UNITS (INTERMEDIATE TYPES) Expansion Joints U; Sr Flexible Metallic Tubing Co^ Keflex Mfg. Die. 301 KEFLEX-KETROL CONTROLLED EXPANSION JOINTS FOR EXTRA SAFETY POSITIVE PROTECTION AGAINST TORSION. FOR USE IN PIPE UNES TO COMPENSATE FOR EXPANSION AND CONTRACTION (Patent Pending) KEFLEX-KETROL, self guiding, anti-torsion, packless type, expansion joints are manufactured with multi-ply. Type 321 or 347, stabilised stainless steel and enclosed by a special alloy steel shroud having two matched sections. Each section has at least four equally spaced finger-type projections at one end, which fit axially into the space between the finger projections of the companion sect-ioD so as to serve as a positive guide to the bellows element and prevent torsion and deflection. The shroud cage the bellows from exterior damage. protects The lengths of the finger projections determine the full extent to which the bellows may be compressed, and also provide sufficient travel to accommodate extension of the bellows in the event ambient temperatures drop below normal and the pipe lines contract accordingly. Steel nngs to prevent over extension of the bellows element are attached to the ends of the finger projections of each companion section. The nngs also maintain complete concentricity of the matched shroud-cage and insure structural stability. KTO-130-2E KTO-150-1S-2E KTO-150-12E KTO-I50-15-12E Rigid flanges supplied on standard Types KTO-150-I2E and KTO 150-15-12E assemblies have a series 15 drilling, but with special elongated bolt holes to permit easy installation in the event companion flange bolt holes are misaligned. TYPE KTO-ISO-2E STANDARD UNITS KTO-1SO-15-2E Ommll Length Sims r-aw'-r - 11.10* Sites IMM4* Ind. Msrimnm Working Pv.i.r. u, 11.00* ISO nr Teapwatare F Traverse Compression * . ' 8001 . . 8.00* Extension o.so* -. ." 88.00* 23.00' ISO 800 4.00*. 1.00' . KTO-1SM2E 18.60* 13.00* . ISO . TOO 8.00* 0.S0' .- RTO-IS-12E 28.00* 28.00* ISO 800 4.00* 1.00* KTO-300-2E KTO-300-15-2E KTO-300-14E KTO-300-15-14E When flanges are required, KTO 300 are fitted with lap joint or swivel flanges. 150 lb type are standard;'300 lb type and heavier are available. . STANDARD UNITS . TYPE KT0-30MJ-2E KTO-300-15-KE Overall Length Sixa i'-lTV-r Sinn W-MMncL Maximum Working Piamt D> Maximum Temperature F Traverae Compresion TYPE KTO 450 Pressures to 450 psig--Temperatures to 800 F. For 2 in. Traverse in Compression and X in. in Extension Type KTO-450-2E with Ends Beveled for Welding Type KTO-450-14E with 300 lb, Type Lap Joint Flange For 4 in. Traverse in Compression and 1 in. in Extension Type KTO-4SO-15-2E with Ends Beveled for Welding Type KTO-450-15-14E with 300 lb, Type Lap Joint Flange NOTE: Type 450 measurements are essentially the *rna m type 300 listed above, except 450 standard flanges are series 30 (300-lb type) . *  302 XJ. S. Flexible Metallic Tubing Co., Keflex M/g. Oiv. * Expansion joints KEFLEX-MAVE TYPE M PIPE GUIDES FOR CONCENTRIC GUIDING OF PIPE LINES KEFLEX Type M pipe guides control the longitudinal movement of pipe and protect expansion joints from lateral deflection caused by bowing or bending of pipe lines. The fabricated steel shell and the inside clamp permit complete insulation of pipe at all points. Type M pipe guide is made of fabricated steel protected inside and out with a suitable finish. The body consists of a guiding cylinder with an anchor base welded on. The top half is removable for easy installation. . . The pipe clamp is made in halves bolted together with the bore being H in. larger than the OD of the pipe. Set screws, in sixes 6 in. and larger, center the pipe and secure the clamp which moves through the body with the expansion and contraction of the pipe. The "ears" of the clamp ride on the inside surface of the cylinder. Available for traverses of 3 in.-4H in.-6 in.-9 in.-12 in., and for insulation thicknesses of I in.-1H in.-2 in.'-3 in. KEFLEX-PULSCO TYPE P SHOCKTRAP FOR PIPE LINES, REFINERIES, CHEMICAL PLANTS, AIRCRAFT AND MARINE FUEL LOADING SYSTEMS KEFLEX Type P Bellows shock traps are used to eliminate "water" hammer and reduce pressure surges in pipe lines operating under extremely high velocities, pressures, and hasardous "stop and go" flows which result in broken lines, meters and overstressed loading equipment* particularly where quick closing valves are used. Type P is constructed of A-2S5 grade C steel enclosing a KEFLEX laminated Type 347 stainless steel bellows with a gas volume sealed in. The entrance to the shock trap is fitted with a special shuttle valve, consisting of an orifice restriction and a bleed hole for fluid exiting from the shock trap, and is guaranteed not to recycle. Surge resulting from the kinetic energy of the pipe line is absorbed by compressing the gas within the KEFLEX Bellows and by friction through the orifice in the shuttle valve. The orifice in the shuttle valve is so aixed as to provide the minimum gas volume for absorbing the surge. Kinetic energy in the pipeline is then converted into friction heat and into the work of compressing the gas in the KEFLEX Bellows gas chamber. Expansion Joints V. S. Flexible Metallic Tubing Co,, Keflex Mfg. Div. KEFLEX EXPANSION JOINTS 303 KEFLEX Type 151-2E expansion joints in large sizes are particularly adaptable to ducting lines and wind tunnel installations as their high flexibility reduces anchor load requirements. The force, to compress KEFLEX expansion joints is usually less than 100 lb. The use of multiple laminations (or plies) of thin stainless steel, longitudinally welded, assures a long cyclic life for the unit and great resistance to pressures. 24 and 48 in. Type 151-2E Expansion Joints Type KST300-15-14E Dual Springtrol Expansion Joint KST300-15-14E KEFLEX Springtrol assemblies are for use as controlled expansion joints where lateral deflection also occurs. Spring controlled tie rods sup port the long center section, between the bellows sections, and prevent over compression and extension. Type KG300-14E Gimb&I J'ypc Expansion Joint KG-300-14E KEFLEX Gimbal (hinged) joints are used when controlled lateral deflection is required and axial movement must be prevented or held to a mini mum. The force to deflect KEFLEX joints is usually less than 100 lb. i Type 158-12 VSP for Diesel Exhaust KEFLEX* Type 158-12VSP Vibration absorbers are designed for use on diesel engine exhaust manifolds. They are usually fitted with a telescoping, self-guiding, full bore, liner to prevent direct impingement of flame on the bellows. They will absorb axial movement as S well as the required lateral deflection. Flanges are furnished to match the drilling on the engine. U.S. FLEX-KEFLEX EXPANSION JOINT MULTI-UNIT Type 308-15CAB-14E. Traverse Provided for job Requirement MILITARY SPECIFICATIONS U. S. FLEX KEFLEX Expansion Joints may be furnished to conform with Military Speci fications MIL-E-178l3a, Type I or II and Class 1 or Class 2.  304 Fillings and Flange% rip* wMia* THE BABCOCK & WILCOX CO. riw TUBULAR PRODUCTS DIVISION FITTINGS DEPT. 3839 WEST BURNHAM ST. MILWAUKEE 46, WISCONSIN SEAMLESS WELDING FITTINGS AND FORGED STEEL FLANGES DISTRICT OFFICES Atlanta 8, Ga......................830 W. Peachtree St. N.W. Beaver Falls, Pa.................................712 Eleventh St.. Boston (Wellesley 81), Mass................. 66 Central St. Chicago 3, III........!............................ 105 S. LaSalle St. Cincinnati 6, Ohio.........................2330 Victory Pkwy. Cleveland 14, Ohio.......... 1420 Natl. City Bank Bldg. Detroit 26, Mich................................... 1717 Ford Bldg. Houston 19, Texas................................. 2134 Welch St. . Los Angeles 17, Calif................. 1111 Wilshire Blvd. Milwaukee 15, Wis............................ .. .2430 S. 28th St. New York 17, N. Y.................................. 666 Third Ave. Philadelphia 2, Pa. . '.......................... 2222 Packard Bldg. St. Louis 8, Mo.........................................3615'Olive St. San Francisco 3, Calif................................785. Market St. Syracuse 3, N. Y........................................731 James St. Tulsa 3, Okla____-....................................... 427 S. Boston St. 90 Long Radius Elbow 180* Long , Radius Return / Straight Tee Concentric Reducer Cap Stub End B&W Welding Fittings and Flanges are available in carbon, alloy and stainless steels in a wide range of sizes. Typical types and size ranges are listed below. For information on the complete line of B&W Seamless Weld ing Fittings and Flanges, write for B&W's Welding Fittings Catalog FB-76. . Carbon and Alloy Steel SUinlca Steel Type of fittin* Wei*bt Strong Schedule 160 Doable Soo", Schedule Schedule Schedule Schedule 45 Elbows--Long radius 90* Elbows--Long radius 90 Elbows--Reducing-- M"36 H-38 H>2~-3366 2x1 to 2x1 to 1-24 1-24 -- M-8 M-8 -- H-24 M-24 -- M-24 M-24 -- 4-24 >4-24 -- M-24 >4-24 -- Long Radius ` 90 Elbows--Short Radius 12x10 12x10 1-30 1M-30 -- -- -- -- .-- -- 180* Returns--Long Radius K-30 M~30 1-24 2-8 X-24 >4-24 >4-24 >4-24 180 Returns--Short Radius 1-30 1M-30 -- ---- -- --` -- Tees--Straight M-36 K-36 H-24 K-8 H-24 >4-24 >4-24 K-24 Tees--Reducing Outlet M*M to M*M to M*M. to M*M to MxM to M*M to M*M to M*M to 30x20 30x26 24x2C 8x6 24x2C 24x20 24x20 24x20 Reducers--Concentric and Eccentric Caps , Stud Ends--Lap Joint Laterals--Straight and \x% to i*H to lxH-to IxH to IxH to 1*14 to \x% to lx>4 to 36x3C 36x30 24x20 12x10 24x20 24x20 24x20 24x20 1-36 1-38 1-24 1-8 1-24 1-24 -1-24 1-24 M-24 H-34 1-12 1-8 K-24 K-24 >4-24 >4-24 1-24 1-24 -- -- On Application . Reducing Crosses--Straight and K-24 H-24 - - On Application Reducing Swaged Nipples Bull Plugs Shaped Nipples 90--45* On Apt lication On Application 2-12 2-12 -- -- -- _ -- - . - -- -- -- . --. -- -- -- -- -- - -- -- -- Saddles--Sleeves . 1-30 -- -- -- -- -- -- Welding Neck Flange Slip-on Flange Blind Flange Type of Flange Welding Neck Slip-on Lap Joint - Threaded Blind Socket Welding Reducing . . . Slip-on and Threaded iso ib 300 lb 400 tb 600 lb 9001b 1500 lb 2500 U> Vt-TA >4-24 >4-24 M-24 M-24 M-24 M*M~ 24x4 V4-24 M-24 M-24 M-24 M-24 M-4 M*M24x4 M-24 M-24 M-24 M-24 M-24 K*M24x4 M-24 M-24 M-24 M-24 M-24 M-3M M*M- 24x4 M-24 M-24 M-24 n. M-24 M-24 M-24 M-12 M-24 ' M-12 M-12 M-12 M-12 M-12 'Sfc'M*M24x4 M*M12x3M FA-8907 - Fittings and Flanges w*uiac Speetmhiee LADISH CO. 305 Cudahy (Milwaukee Suburb) Wisconsin PLANTS IN: Cudahy, Milwaukee, Kenosha, Wis., Los Angeles, Calif., to am rmicss ATLANTA, GA..........U71 Peachtree Street, N.E. BATON ROUGE. LA.............1170 Florida Bird. BRANTFORD. ONT.. CAN......... Park Rond, N. BUFFALO. N. Y.................... 14 Lafayette Square CALGARY. ALTA., CAN.........S51-13 Are., B.W. CHICAGO. ILL.................. W S. Michigan Are. CINCINNATI. OHIO..................1282 Aldrich Ave. CLEVELAND. OHIO................... 827 Hanna Bid*. DALLAS. TEXAS...................211 N. Erray Bid*. DENVER, COLO.......................... 1700 Broadway Houston, Texas, and Brantford, Ontario, LADISH SALES OFFICES: DETROIT, MICH........ISMS W. Eight Mile Rd. HAVANA. CUBA........ P. O. Box 000-283 Chacon HOUSTON, TEXAS--1201 West Belt Drive N. LOS ANGELES, CALIF.......tttl E. Slaam Ave. MEXICO CITY, MJEX ___ Bocaavista No. 2, Despacfao 60$ MONTREAL. QUE, CAN......... New Btries Bid*. NEW YORK. N. Y.................. (0 E. 42nd Street ODESSA. TEXAS...................... 819 W. 4tb Street PHILADELPHIA. PA............. 1489 Locust Street PITTSBURGH, PA...................3020 Grant Bid*. ST. LOUIS. MO......................... .WIS Olive Street ST. PAUL, MINN............... 2288 University Ave. SAN DIEGO. CALIF...............6083 Harbor Drive SAN FRANCISCO, CALIF.... .420 Market Street SEATTLE, WASH............. *14 fairview Ave., N. TORONTO. ONT.. CAN..........U YorkriBe Are. TU1SA. OKLA. ISO* let Natl Bank end Trust Bid*. LADISH ... A COMPLETE LINE OF PIPE FITTINGS BUTT WELDING FITTING^ (IPS and Tube O.D.): Sues Vt in. through 42 in. Ranging from IPS Schedule 5S through double extra strong and special wall thickne*es through 5 in., plus complete range in Tube OX). Fittings. These butt welding fittings align accurately for sound, fast welds to form an integral piping system.of continuous efficiency. Smooth, flush, leak-proof joints reduce turbulence and pressure loss...and provide assurance of product uniformity. FLANGES, LONG NECKS, ROLLED RINGS: ASA, MSS, Light type and Corrosion Weight Flanges is sizes Vt in. through 24 in --in pressure ratings ISO lbs through 2500 lbs; Large OD. and TJdA. Flanges in sizes up to 24 feet dia; Long Necks in sizes 1 in. through 24 in.--in pressure ratings 150 lbs through 2500 lbs; Rolled Rings, seamless or welded, are available in diameters up to 24 feet and in weights up to 140,000 lbs. All parts forged under exacting metal lurgical controls, accurately machined to full dimensions. SCREWED & SOCKET WELDING FITTINGS & UNIONS: Forged Fittings in sizes Vs in. through 4 in.--in pressure ratings 2000 lbs through 6000 lbs. Sharp, dean threads of Ladish screwed fittings assure tight, leak-proof joints. Wide reinforcing bands provide ample wrench grip surface and extra strength at stress points. Socket Welding Fittings have deep, true welding sockets to assure proper alignment and slip fit. 150 lb STAINLESS STEEL SCREWED FITTINGS are also available in a complete range of sizes and, types. ' INDUSTRIAL TRI-CLAMP STAINLESS STEEL FITTINGS: The industrial type Tri-Clamp Stainless Steel line presents a unique design concept in a disfnountable fitting with particular application in process lines demanding con tamination-free product flow. Available in sixes lM in. through 12 in, in IPS or Tube O.D_, in type 304 and 316 stainless steel. Tri-Clamp fittings make possible a light weight system with smooth inner walls... unobstructed flow... and no pockets and. crevices to cause hazards of contamination. Simple assembly features ... combined with light weight... asure fast, easy assembly and dismounting of lines for thorough cleaning, brushing and sterilization. Tri-Clamp line is assembled by either expand-on or weld-on methods. i^AvajlaHle^h . .Tj . -.-AlUMINUM'.'NICKti,--.-'::; }^w|^!T.A;NfyMSA'ri|gdTHiRJ^ [^|ARRqus'(ANpTNpN; A COMPLETE SERVICE TO MEET ANY REQUIREMENT: Ladish offers complete service in pipe fittings regardles of type, size, pressure rating, wall thickness or material specification. Special emphasis on metallurgieally sound materials and forging procedures ... combined with advanced engineering... and rigid manufacturing controls assures users of Ladish fittings a uniformly high standard of dependability. - CATALOGS AVAILABLE 304 page Ladish Carbon and Alloy Fittings Catalog No. 55 ... and 86 page Stainless Steel Fittings Catalog available on request. Contact your authorized Distributor, your local Ladish sales office, or write Ladish Co., Cudahy, Wisconsin. 306 Fillinga and Flanges THE PIPE LINE DEVELOPMENT COMPANY 5700 DETROIT AVENUE CLEVELAND 2, OHIO TELEPHONE: ATLANTIC 1-3233 EXPORT OFFICE: R. S. STOKVIS & SONS. INC., 17 BATTERY PLACE. NEW YORK 4. N. Y. Weld+Ends Permits Welding a Pipe Line While Pumping Through It WELD-fENDS is used as a safety welding coupling on crude oil, gas, gasoline, propane, asphalt, tar, steam and other pipe lirieff, As soon as packing rings and clamping screws are tight ened, pipe line flow is resumed. After pipe line is restored to service, WELD+ENDS is welded to pipe, making a solid, all- welded joist. PLIDCOFLANGE Plidcoflange is brand new. There are counties applications where this fluting excels. It dips over the end of the pipe, seals ofl like WELD+ENDS and mates up with standard flange facings. . Plidcoflange may be welded permanently to the pipeline while pumping or it may be bolted in place, permitting removal. Plidcoflange is outstanding for use as a blind plate flange. Simply slide Plidcoflange back to change plates. Flange spreaders and jacks for springing pipeline are not needed. Available jn sines 2 in. through 12 in. with 150 pound ASA. standard steel flanges. Other sizes and pressure classes on ap plication. * New Smith+Clamp Permits Plugging and Welding Pit-Hole Leaks in a Pipe Line While Pumping Through It SMITH + CLAMP utilizes a unique pilot pin. (See "A" in illustration at right.) Pin projects from Neo prene leak cone (C) and guides point of cone directly into leaking hole. Pilot pin is removable. After cone is pin-pointed on leak,. pressure is ap plied directly behind cone by means of Force Screw (B), thus forcing cone point into hole and stopping leak. Makes it possible to control higher line pres- ' sures with lower bolting pressure. ' SMITH + CLAMP is available in sizes 1 in. through 36 in. or larger. . WELD PLATES are also available in sizes from 4 in. through 36 in. WELD PLATES are companion pieces, required only where welded repairs are speci fied. They fit over the Clamp and weld to pipe, mak ing a permanent, all-welded, steel plate repair. . Leak' Cones, available in various diameters, are ' made of Neoprene in the standard models. Also avail able in Silicone * (for higher temperatures), Teflon, Steel, Lead and other materials. Fitting* and Flanges wwi=* speuiui 307 TUBE TURNS DIVISION OF CHEMETRON CORPORATION General Offices and Factory: Louisville 1, Kentucky Branch Offices 1605 Atlanta Federal Sav. Bldg.--Jackson 2-7310 CHICAGO.........................600 S. Michigan--Harrison 7-8526 DALLAS.............309--311 Meadows Bldg.--Emerson 1-1912 DENVER...................................1160 10th St.--Cherry 4^807 DETROIT...............2591 West Grand Bird.--Trinity 3-7938 HOUSTON.................7120 Katy Road--Underwood 9-3531 KANSAS CITY 5019 W. 55th Su, Mission, Kansas--Westport 1-8111 LOS ANGELES............2417 East 24th St.--Ludlow 7-8287 MIDLAND, TEXAS............3209 Lockheed--Mutual 2-5743 NEW ORLEANS............1205 St. Charles Ave.--Tulanc 5611 NEW YORK...........................150 Broadway--Rector 2-8230 PHILADELPHIA 1032 Sub. Station Bldg.--Locust 7-3218 PITTSBURGH...............1718 Grant Bldg.--Atlantic 1-8848 SAN FRANCISCO.............2611 Russ Bldg.--Garfield 1-2594 SEATTLE.............$510 E. Marginal Way---Parkway 2-7500 TULSA.........................704-05 Wright Bldg.--Cherry 2-9193 In Canada: TUBE TURNS OF CANADA LIMITED, Ridgetovra, Ontario Toronto, Edmonton, Montreal & Vancouver ' Distributors in Principal Cities j liBE"TURH lOelfluuj and -J-lattqea- In sizes in. through 42 in.... in all types ... all wall thicknesses ... and all piping materials Tube Turns ia the originator and pio neer manufacturer in the development and use of seamless, forged welding fit tings. This company offers fittings and flanges in all sizes and types for every pipe welding need. A few of the many ad vantages of Tube-Turn fittings are listed here. Complete details are included in the Tube Turns Catalog Sit, sent on re quest. Outstanding Advantages of TUBE-TURN Welding Fittings These sound advantages are solid rea sons why Tube-Turn welding fittings are universally preferred today: (1) Stronger, lighter, tighter piping systems. (2) Permanently Irak-proof, trouble-free construction. (3) Uniform wall thickness of elbows and returns throughout, mak ing possible exact alignment for better, taster, lower-cost welding. (4) Minimum maintenance cost: (5) Easy sweeping changes in direction reduce pressure loss.(6) Smooth inner wails for more effi cient flow, less corrosion and longer life. (7) Proper grain structure with no inter nal stresses. (8) Easier to insulate. (9) Accurate dimensions that permit prefab rication of whole sections. Materials and Construction Regular carbon steel Tube-Turn el bows and returns, in both long and short radius types, are made in Standard, Ex tra Strong and (in long radius only) Schedule 160 and Double Extra Strong, pipe thicknesses. These fittings conform to ASTM specifications A-234. TubeTurn welding fittings in other schedule numbers and special thicknesses are like wise available. They are aIso made of types 304, 347 and 316 and other stain less steels, corbon-moly and chrome-moly steels, copper, brass, nickel. Monel, In conel, wrought iron and aluminum. The uniform high quality of TubeTurn elbows and returns is due to their unique and original manufacturing process --in which short sections of seamless tub ing are forced over a curved expanding mandrel at a forging temperature. Tube- Turn tees are also made by an exclusive process and to a design that provides many special advantages. Other TubeTurn fittings offer similar quality stand ards. ' Fine Grade Forged Steel Flanges Tube Turns manufactures a complete line of forged steel flanges of outstanding strength and dimensional accuracy. Valuable Technical Data Available Several items of authoritative technical literature on fittings, flanges and piping in general are available as are bulletins giving specification information on types, sizes ana materials. Write for descriptive leaflet. Distributor Stocks Throughout U. S. and Gannd Tube-Turn welding fittings and flanges are available from distributors located in every important city and area in the . United States and Canada. . ` "tt" and '`Tube-Turn*' Reg. U. S. Pat. Off. TUBE-TURN FITTINGS,AND FLANGES - IN TYPES, SIZES, WEIGHTS FOR EVERY PIPE WELDING NEED & a Straight Tee ' Cap : RatStts Elbow 45* Lout Radios Elbow IfitT Long Rsdhts Return Extra Loot Radius Return 180* Short Radios Retain Reducing Outlet Tee StraiEtt Cres* Cooceaflfc ktttuot Stn&tt Literal MSSm Reducing Bbow SceJe-fres CeupQug Eccentric Reducer Sleeve Up Joint Stub Eed ^ Welding (TO \J Rjrip y 4s Groove' Wsm* Welding Neck Rap SBp-eo Flange Up Joist Flange - Threaded Flanp B&ad Rasp  308 Dept. H. Arthur Harris & Co. 210-218 N. Aberdeen Street Engineers--Metal Float Manufacturers Floats Chicago 7, 111. Harris Floats Harris Floats are made in a wide range of sizes in ball, column, disk, conical, cylindrical and rectangular shapes, and can be made of virtually any workable metal for open tank or high pressure and temperature installations. Some of the metals used in the manu facture of Harris Floats are Copper, Copper Plated Steel, Brass, Aluminum, Admiralty, Everdur, Monel, Nickel, Inconel, Stainless Steel, types 304 and 316, etc., and Steel, depending on the corrosion factors of the installation and the pressures under which they must operate. . Harris Copper Ball Floats Harris Copper Ball Floats are made of two separate bodies, soldered together and then heavily copper plated to provide a seamless surface. They are usually supplied with a hexagonal female spud although other special connections can be furnished. These seamless copper ball floats are carried in stock in 3. in., 4 in., 5 in., 6 in., 7 in., 8 in., 10 in. and 12 in. diameters ... foT 25 lb, 50 lb, 100 lb and 150 lb working pressures. Special sizes to 18 in. diameter and special high pressure'copper floats are made to order. Harris Stainless Steel Ball Floats Harris Stainless Steel Ball Floats for low or high pressure and Corrosion Resistance are carried in stock in diameters of 2)4 in. to 12 in. Sizes from 12 in. to 14 in. diameters are made to order. All Harris Stainless Steel Floats are joined by Atomic Hydrogen welding which produces an unusually smooth, uniformly strong and ductile weld, free from oxides or pin holes. Corrosion Resistant Floats Floats that must operate in corrosive liquids can be made of any workable metal that is resistant to the specific liquid in which they are to be used. - Plated Floats floats pad be plated with copper, nickel, chrome, zinc, tinned or lead coated where called for by the installa tion. . Float Connections A variety of connection styles are available, suitable for practically any type of attachment, including a tube through the center. A very complete catalog, with much technical engineer ing data is available to prospective float users on re quest. The Harris engineering staff will be glad to consult with you on any float, problems. . Heating Systems . BURGESS-MANNING COMPANY A'lcUiiectevuJ. PnoJudi. Sbioilitug 5970 Northwest Highway, Chicago 31, III. ' Distributors in Principal Cities 309 A suspended metal pan ceiling that supplies: 1. RADIANT PANEL HEATING 2. RADIANT PANEL COOLING 3. ACOUSTICAL CONTROL The radiant panel principle of this modem ceiling provides HEATING AND COOLING independently of air movement. * For the heating cycle, hot water is circulated through the pipe , grids. The aluminum ceiling panels, which are clipped directly to the grids are heated by conduc tion; thereby making the entire BURGESS-MANN ING FUNCTIONAL CEILING a radiator which in turn radiates to every surface and object in the room, nature's way of controlling human comfort. For the cooling cycle, cold water (above the dew point) is circulated and the above described heating cycle is reversed. ' Uniform air temperatures are maintained, convec tion drafts and heat shadows are minimized. Concen trated heat sources and overheated air are eliminated. THE BURGESS-MANNING 3-WAY FUNCTIONAL CEILING CREATES A NEW STANDARD FOR COMFORTABLE WORKING AND LIVING CONDITIONS The BURGESS-MANNING CEILING carries the Entire Heating Load. The B-M CEILING carries the Entire Sensible Cooling Load (in most cases). Air requirements are limited to latent heat removal and ventilation requirements; Reduced air handling equipment and smaller ducts SAVE BUILDING CUBAGE. Heating and/or cooling source, entirely in ceiling, gives unrestricted use of the TOTAL FLOOR AREA. Standard hot water controls are utilized. Response to temperature change is instantaneous--No Lag or Over run. Simple modular system lends itself to flexibility in layout of partitions, lighting and air distribution. For design procedure and performance curves send for catalog A-188-8-G.  310 Heating System* n*n linrrl tUdreil--i B^Jer-Banef Unit* GENERAL AUTOMATIC PRODUCTS CORP. 2300 Sinclair Lane Baltimore 13, Md. FLOORLEVEL BASEBOARD HEATING Manufacturers of a Complete Line of Residential Gas and Oil Heating Equipment and Summer Air Conditioning RATINGS Reg. u. s. pm. off Floorievel BR-2M A %" Copper Tubing Fins: Rectangular Aluminum deep X high X 0.012, 54 fins per foot WATER Average Water Teaper*tort, F Btu/br per Line** Foot 500 Ib/hr 3000 lb/hr 165 430 450 170 500 * 175 500 540 180 530 570 185 570 610 190 600 . 640 195 . 630 . 690 200 670 720 205 700 . 760 210 730 800 215 770 840 220 800 870 Floorievel Model BR-2M A has been tested and approved by the Institute of Boiler and Radiator Manufacturers under the 3d edition of the I=>B=R Rating Codes- Approval date June 10, 1958. . . DUAL DE-AIRATOR TANK A complete unit with feed and relief valve, lor positive elimination of air in hot water heating systems; also acta as an expansion tank. Three sites--500, 1,000 and 1.,500sq.ft. SERIES "LG" GAS-FIRED BOILER- BURNER UNIT Available for natural, manufactured, mixed or L.P. gas. All units only 31 in. high, completely assembled. Controls available to meet all Ideal code require ments. . SPECIFICATIONS; Model ACA. lUtings Btn Input Rtu Output Sq Ft Output LG-4 to 84,000 to 67,200 to 448 to LG-10 210,000 168,000 . 1120 CARTON "A" contains: JO ft of Floorievel Baseboard complete with heating ele ment and necessary brackets; 2 rubber grommets, 2 splice pieces. (Approximate shipping weight 28'lb.) '' ' ~ CARTON "B" contains: 10 ft of Floorievel Baseboard complete with heating ele ment and necessary brackets; 10 ft of extra enclosure only with necessary brackets, 4 splice pieces and 2 rubber grommets. (Approximate shipping weight 50 lb.) CARTON."C" contains: 10 ft of Floorievel Baseboard complete with heating ele-. meat and necessary brackets; 3 inside corners, 1 outside comer, 4 right-hand comers,4 left-hand comers, 1 wood block (used where wood baseboard meets enclosure), 2 rubber grommets, 2 splice pieces. (Approximate shipping weight 33 lb.) CARTON "D".contains: two 10 ft sections of Floorievel Baseboard complete with heating element and necessary brackets; 4 rubber grommetB, 4 splice pieces. (Ap proximate shipping weight 55 lb.) CARTON "E" contains :*two 10 ft lengths of front and back panel, 10 brackets, 2 top .moulding splice pieces, 2 front panel splice pieces. (Approximate shipping weight 44 lb.) :` OIL-FIRED BOILER BURNER UNITS "LQ" >* prc-vrired sod mn mi n~mhlnrl, oocapfct* with burner, 3 controls and circulator. Available tn Model No. Bta Input Btu Output LO-fl LO-7 140,000 168.000 1061X10 129.000 M0 Series *T" Steel water-tube Boiler-Bureer aflit, constructed to ASMB Code, Available io following isca and ratings: __ Boiler Ratings ED& Model No. Hot Water SqFt ' Steam Sq Ft T-16 to T-40 M0 to 4S00 0 to* Also manufacturers of a complete line of eummer and winter air-eonditksiung equipment. Hatting Systems . iw Beaten, * Cells. Converters, Badlaten KRITZER RADIANT COILS, Inc. 311 325 NORTH RIVER STREET BATAVIA, ILLINOIS "R"LINE RadiantBaseboardfor RESIDENTIAL, COMMERCIAL, r1: INDUSTRIAL and INSTITU TIONAL HEATING Quick end easy to install with many KRITZER features (at no extra cost) gg* such aa Coil Support Brackets,. Sliding Coil Shoes, ana Thermovane Damper. Capacities shown below are representa tive of the wide selection available with KRITZER Radiant Baseboard. ' Coyoetl*** per linearZee*. AituitiF Element Symbol J74-4QA 31-40A >1-40 STB . I p* STEAM J00F Cover 8qFtper Btu per Water Symbol Lu. Ft lin. Ft (1 gpm) K-l KtM KU-1 3.80 4.40 1.00 840 1088 6--38 Get BULLETIN ?ao 203 f?r 00rn- pfete informa. tion Radiant Baseboard for SCHOOLS, HOSPITALS, OFFICE BUILDINGS, INSTITUTIONS, and FACTORIES Sturdy. Lifetime of efficient service. Haa such KRITZER featares (at no extra cost) as . Adjustable Coil Support Brackets, Coil Shoe, and Damper and Control. Capacities shown below are but a few of the wide selection available with] KRITZER STB Radiant Baseboard. "SPECIAL" Ra diant Baseboard for HOMES, APARTMENTS, HOTELS, MOTELS, OFFICES Low cost baseboard with many KRITZER quality features: Thermovane Damper, snap-in Coil Support Brackets, Sliding Coil Shoes, Built-in Air Diverter, packaged in convenient lengths. Capaci ties shown below are representative of wide selection available. BULLETIN 350. Capacitie* ptr linear foot. Air at UF dement Symbol Cover Symbol SP 1 mi cteem Sq ft per lin (t 2.7 200F (l gpm) 175-SOA 8PU SPU 3.8 600 730 Cajtfctb,, per Unrer foot. Air at tip t P* STEAM 100? Element Cover Sq Ftper Bin per Water Symbol Symbol ue. Ft Lin.F* (2 gpm) 31-40 4125-40 42-4Q 412S-4QA STB3-1 8TB4-1 STB4-1 8TB4-1 8.1 12386.7 1610 6.3 U10 7.6 1368 070 1220 1090 1445 mini, mum height from floor Write for complete information Dasl-Yectors Fan-coil units for heating and cooling with hot or chilled water. Two models: Free standing (DVF), and Semi-recessed (DV) which fits between standard studs. . Optional outside air intake and dual room conditioning accessories. Sixes in 200, 300, 400, and 600 cfm. Write for . BULLETIN lOOt-T. Cabinet Unit Heaters Quiet, - economical -units used in areas calling for rapid concentration of heat such as meeting balls, churches, and large public recreation rooms. - Six basic rises. Standard or high ca pacity coils--500 to 1200 cfin. Up to 430 EDR. . Floor, wall, inverted wall, or ceiling mounted. Only 32 in. high and 10 in. deep. m iifSnvIS ------------- : lubricated bearings. . Trim strips, 3 or 4 sides, for full or partial recessing. i- 4 speed control available. AU piping can be kept inride of cabi nets. Send for BULLETIN ItOO-T Unit Heaters All^mls hajB dynamically balanced, propeller type fans in deep venturi for quiet, efficient operation. Rubber mounted motors. Heavy gage steel cabi nets. Baked-on enamel finish. Wide selec tion of sixes for steam or hot water. Write for BULLETIN 800. WE WELCOME YOUR INQUIRIES ON SPECIAL APPLICATIONS Floor, wall hung and recessed models. Famous KRITZER coil construction for steam and hot water. Brcnxe headers. Heavy, reinforced steel cabinets. Full range of sixes. Chain or knob operated dampers. Cabinets phosphatixed. Gray prime baked-on finish. Write for BUL LETINS 600 and 601. #312 Heating Systems Buafcmd, Panel Shaw-Perkins Manufacturing Company 201 East Carson St. Pittsburgh 19, Pa. Manufacturers of SHAW Panel-Vectors delivering AIR-e-ATED Radiant Heat All Shaw Panel-Vectors and Perkins AIRadiators are complete one-piece factory assembled units ready for installation. Manufactured of heavy gage steel with full-length heating fins and vertical serpentine copper beating coils, pressure fitted for excellent heat trans fer. Numerous sizes and models available to meet any area heat loss. Institutional models possess perforated paneling for low surface temperatures. Perkins AIRa diators axe designed for industrial installations, and are readily mounted on either ceilings or walls. SIIAW Panel-Vectors (front or top air outlets) DEPTH, front to back--3 in. HEIGHTS--8 in., 11 in., 14 in., 17 in., 20 in., 23 in., 26 in. LENGTHS--11 in. to 111 in., inclusive, in-2 in. increments. TAPPING--supply and return same end, right or left hand; also furnished on opposite ends.'PIPING--connections for }^ in., % in., or 1 in. piping. RATINGS--3.9 EDR to 117.7 EDR, based on 1 lb steam and 65 F inlet air. INSTALLATION--wall hung, free standing, open or closed recess. APPLICATION--hot water, high temperature not water, steam to 150 psi. End panels, air chambers, wail brackets available for any application. ' ` SHAW BASEBOARD Panel-Vectors DEPTH, front to back--3 in. HEIGHT--8 in. LENGTHS--2 ft 5 in. to 72 ft 7 in. inclusive, in 2 in. increments. TAPPING--supply and return same end, right or left hand; also furnished on opposite ends. PIPING-- connections for in. piping on same end, 1 in. piping on opposite ends. RATINGS--6.7 EDR per linear ft based on 1 lb steam and 65 F inlet air. INSTALLATION--wall hung with inside and outside comer runs. APPLI CATION--hot water, steam to 150 psi. End panels, air chambers, and mounting screws included as standard equipment. . SHAW INSTITUTIONAL Panel -Vectors DEPTH, front to.back--3 in. HEIGHTS--8 in., 11 in., 14 in., 17 in., 20 in., 23 in., 26 in. LENGTHS--11 in. to 111 in. inclusive, in 2 in. increments. Steel housing has $4 in. diarq. perforations on Mg ip- staggered centers. TAPPING--supply and return same end, right or left hand; also furnished on opposite ends. PIPING--connections for }$ in-, % in-, or 1 in. piping. RATINGS--5.0 EDR to 100.9 EDR based on 1 lb steam and 65 F inlet air. INSTALLATION--flush mounting for violent areas, offset mounting for non-violent areas. APPLICATION--hot water, high tem perature hot water, steam to 150 psi. End panels for complete pipe covering. PERKINS AIRadiator . DEPTH, front to back--5 in. HEIGHTS--14}$ in., 23}$ in., 32}$ in. LENGTHS--15 in. to 125 in. inclusive, in 2}$ in. increments. TAPPING --supply and return on opposite ends; top and bottom arrangement reversible by reversing radiators. PIPING--connections for 1 in. piping; may be bushed to }$ in. or % in. as specified. RATINGS--14 EDR to 187 EDR based on 1 lb steam and 65 F inlet air. INSTALLATION--ceiling or wall hung. APPLICATION--hot water, high temperature hot water, steam to 150 psi. Ceiling hangers or wall brackets available for mounting. Represented in principal cities. Send for catalog. Heating Systems iudunt AIRFLOOR Company of California, Inc. 313 13729 E. Rosecrans Avenue, Sante Fe Springs, California HOLLOW CONCRETE FLOOR PANEL FOR SINGLE AND MULTI-STORY CONSTRUCTION Warm Air Radiant Heating and Ventilating or Complete Air Conditioning for Schools, Churches. Residences. Hospitals. Industrial Buildings Airfloor forms create a strong, hollow floor serving as a common plenum for conditioned air, radiant heat, and positive mechanical ventilation for complete air-conditioning systems. Airfloor introduces all air passing through the floor into the occupied space. For use with Gas, Oil, Electric, or Coal Fired Furnaces, fan-coii units, multi-zone units, etc. am sumv w ta. far hspMioA. Ugfadne * Grifc* AIRFLOOR Truss Slab Provides: 1. A. one-way or two-way truss within the dab. 2. A flat .dab construction, which may be poured in place or lifted in place allowing flexibility of partition locations. 6. A plenum or duct through which conditioned air passes thus providing a radiant panel and simultaneous convection heating or cooling. . 3. A ceiling already in place. . 7. More utilixable volume in multi-story buildings, by elimi 4- A reduced load of 3$ pounds per square foot which in turn reduces concrete weight, supporting column, beam and foundation sizes. nating required space for exposed ductwork at each floor level, litis is especially important where limit-height build * ings are concerned. 5. A considerable reduction in seismic forces due to floor dead loads. 8. The ease of installation of hidden piping and electrical work. The necessity for rigid electric conduit is eliminated. 9. Flexibility in partition locations. ' AIRFLOOR FORM SPECIFICATIONS STANDARD MATERIAL: 26 gauge cold rolled ateeMgal- vaoized steel forms optional at extra cost). ' STANDARD WEIGHT1. One pound pet sq ft. . was applied to a six inch diameter (0.196 square foot) disc which centered over the one inch thickness of concrete at the center of the form. SIZE: 12 in. x 12 in. x ZV* in. Ibe following tabulation gives the results of this test: CONCRETE DISPLACEMENT: The concrete displaced by one Airfloor form is 0.223 cu ft. ` COMPRESSION LOAD TEST: By California Testing Laboratoriea, Inc^ on June 8,1955, Lab No. 42288: Compression load COMPRESSION LOAD IN POUNDS: 9,250. RESULT: No cracks appeared until failure which fractured the concrete by punching shear at the edge of the disc. FIELD CONDITIONS: Linear gain over installed Airfloor forms: 2 inV32 ft 0 in. AIRFLOOR REGISTER SPECI FICATIONS Material: 20 gage cold rolled steel. Length: 48 in. standard or cut to suit architectural requirements. Height: 6i*. ( Backplate & Dampers: Optional. Finish: Canterbury Blue metal primer. WRITE for complete catalog and specifications  314 Heating Systems National Clay Pipe Manufacturers, 1820 "N" St., N. W., Washington 6, D. C. 311 High Long Bldg., 5 . Long St., Columbus 15, Ohio 703 Ninth and Hill Bldg., Los Angeles 5, Calif. 100 N. LaSalle St., Rm 2100, Chicago 12. 111. Room 406, 1401 Peachtree St., N.E., Atlanta 9, Ga. CLAY PIPE HEATING. VENTILATING, AND AIR CONDITIONING DUCTS Information contained here includes the basic data, needed by engineers, architects, builders, ^nd beating contractors to evaluate and install low-cost Vitrified Clay Heating Ducts in basementiess slab-floor homes and other structures. This' new development has become so popular that many requests for authoritative information have followed the publication of articles about the new system in the trade press. There are three major reasons for its popularity: ECONOMY--The complete Clay Pipe installation is eco nomical and efficient. It combines the advantages of radiant heat and controlled warm-air circulation at greatly reduced costs. The perimeter loop design shown here is used in structures built upon a concrete slab directly on the ground. Its air distribution system includes a warm air duct that extends completely around the perimeter of the building in a'con tinuous loop. The ducts are buried in the slab 2 to 18 inches from its outside edge, and the tops of the bells will be 1V4 inches below the slab surface. Heat is delivered into the rooms by warm air discharged from registers placed in the floor beneath the windows, and by rediant heat from the warm floor surfaces over the embedded ducts. The loop is supplied by feeders -extending from a plenum chamber in the slab. * . SERVICE--Clay Pipe is chemically inert and cannot be eaten away by lime in concrete. It does not rust, corrode, or dis- integrate from moisture and furnace gases. It will not crush or deform as concrete is poured over it. ADVANTAGES--It is well known that the greatest heat loss in a well constructed and insulated building--commercial or residential--will be found at the outside walls and glass areas. This loss will usually average 65 percent of the total structural INSTALLATION--Clay Pipe's handy lengths and easy-to- heat loss. Concrete slab floors will account for approximately make joints permit fast installation and lower labor costs. 18 percent of the total beat loss. The rest of the heat will A wide variety of fittings is available to solve construction be lost through the ceiling or attic. Perimeter heating intro problems with no on-the-job delay, and Clay Pipe cannot duces the heat along the outside walla and along the glas float as the concrete is poured. area. The heat rises and the resulting blanketing effect reduces the radiant heat loss from all outer walls and windows. Further PERIMETER LOOP SYSTEM--The data and' instructions more, this blanketing effect also eliminates air drafts which. contained here apply to the Perimeter Loop system, since it is are caused by the cooling influence of the-walls. The heating more highly recommended by heating authorities. Its pattern ducts/ embedded in the concrete floors, help to maintain eliminates the "waterfall" of cold air at the outer walls and . the floor surface temperature at desired comfortable levels. effectively combats "radiant cold" at the outside edges of It can be seen that perimeter heating accomplishes three impor- the slab. It combines the advantages of forced warm-air heat tant basic functions: first, it replaces the heat that is lost; sec-, ing with heat by radiation through the concrete slab. Heat ond, it replaces the heat at the same point where it is lost; and is concentrated where people are sitting--not at the ceiling. third, it replaces the heat as fast as it is lost. Tests conducted In test installations, the new heating method has cut operating by the National FParm Air Rtating and Air Conditioning costs from 20 to 30 percent by eliminating high beat-loss at ceil ings or attics. Successful research conducted by the National Warm Air Heating and Air Conditioning Association has been followed with great interest by the building and heating indus tries. According to the Association, "Warm Air Perimeter Heat Association at its University of Illinois Research Center and in actual installations throughout the country indicate that temperatures in residential structures can be maintained well within the limits established for comfort conditioning. ing is & highly successful method of heating a basementless building.... It produces the ultimate of occupancy comfort. It is economical to install; can be designed to use a minimum amount of scarce materials; and requires no unusual skill in its design and installation that the heating contractor cannot supply." VERSATILITY--Clay Pipe beating ducts can also be adapted for ventilation and air conditioning purposes. This is another advantage of the under-dab design--the required amount of ventilation air can be circulated through the same distribution ducts used for beating. - FURNACES--Although a down-flow type of furnace is gen erally associated with the perimeter warm air heating system . when installed in basemen(Jess structures, all types of winter air conditioning units can be used. Succesful installations have been made using up-flow types of equipment as well ; as horizontal units. When up-flow furnaces or horizontal sus pended units are used, down-comer ducts are used to connect the warm air plenum of the furnace unit with the distribution - plenum in the floor. Also, two or more furnaces can be installed--each unit having separate control for its own dis* tribution system so that various sections' of the structure can have individual temperature control. However, one unit sized for the entire heat loss can be also installed, using two or . more bonnet outlets with automatically controlled dampers in each. * Under PlMr Duel, National Clay Pipe Manufacturers, Inc. 3!5 Washington 6, D. C. VITRIFIED CLAY PIPE FOR UNDERFLOOR HEATING DUCTS Conforming to ASTM Specifications C-13 . warm air winter air Conditioning systems and all necessary engineering data, ta bles, and recommendations for selection of proper heating equipment. wue intones or t^iay ripe nesting, ven tilating and air conditioning duct in stallations in homes, schools, churches, hospitals, factories, gasoline stations, ga rages, stores, and theatres, write the Na tional Clay Pipe Manufacturers, Inc., 1820 "N" St. N.W, Washington 6, D. C. ErCD) Layiaz langth <L> NonsicjJ, - ft of VtziA- ia. per ft of feaftb WlTI. mum Differ- Least! of fSro Op posite Sidm, ia. Outside Diameter of Barrel, to. Mia. Max. fetid*-- Diameter of Socket tiH in. Beae, ia. (De) Depth of Boeket, fa. (Le) Min. Max. Ts- Tfaiekoees of Barrel, ia. m Nocni<--i Ml-. Thkkaem of Socket - UMin. from Outer' End, ia. TW> Mia. DRAINAGE--When planning base mentless homes, great care should be taken to select only well-drained sites. 1 Perforated Clay Pipe should be used to drain the building site. The drainage line should be laid around the outside of the ' footings and connected to an adequate Jot-drainage system, in the herring bone, gridiron, or parallel patterns. Pipe with perforations half-way around the barrel provides good drainage yet carries off a minimum of dirt in suspension. For home drainage, Standard Strength (ASTM C-211) Perforated Clay Pipe is recommended. 4 2, 2H, 3 X. 6 2, 2%, 3 X 8 2. 2H. 3 X 10 2, 2)4, 3 X X, 5X 5* m ix IX X He K X % 7Kfl 7Hs 8K 8 2K 2 % Xt X H H 9* 9X 10X 11 2* SH X >K. X, X Hs 1W 12 13H 2X 2X H % X X. Than it bo limit for p]oj variation. can be exposed to weather in any season. resistance to shock loads, and resistance to corrosion from lime in the concrete. They create no odor as warm air flows through them during furnace operation. The smooth inner surface eliminates turbulence and minimig^g register noise. The clean smooth surface of the Vitrified Clay Duct is free from dust. --unn xiv neaitng ana Atr ConAiitoninff Association and are contained in the new revised edition of Manual 4 ($1.50) and`Manual 9 ($0.75), which are available from the association's offices, 145 Public Square, Cleveland 14, Ohio. Manual No. 4 describes warm air perimeter heating systems as applied .to structures without base ments. Manual No. 9 contains detailed information on design and installation of Large diameter day pipe heating duet , and plenum connection used in com'tnerdal structure. This type of duet, .. when installed in garages and main tenance or repair shops, can be used for heating, ventilating, air condition ing, and removal of exhaast gases. When registers are located under the windows, the warm air will blanket the glass area and eliminate frosted and wet windows.  316 Heating System* National Clay Pipe Manufacturers, Inc. Washington 6, D. C CONSTRUCTION DATA--All ground beneath the building should be cleared of organic material. A four to six inch layer of coarse fill is then laid--washed gravel, crushed rock, or stone that has been passed over a coarse screen. Cinders or firm sand should never be used for the fill. The fill must be covered with a moisture barrier before the djs poured. This membrane should be the equivalent of a good grade of roll roofing at least 55 lb per 108 sq ft. Strips should be overlapped at least four inches and tarred. The ' barrier must completely cover the area within the foundation walls *r*d extend up the walls to the top ol Ihe dab. See Figure Edge insulation must be placed completely around the concrete slab. Two-inch thick insulation is recommended, but one-inch is acceptable. It is not necessary to anchor the Clay Pipe ducts to stakes, or to surround them completely with concrete (as with lighter materials). The Clay Pipe is laid directly upon the membrane, and gravel or is used to level it. Small depressions should be made in the fill or gravel so the pipe bells "hang free". This facilitates proper pipe alignment ami prevents buckling at the joints. See Figure 2. MOISTURE MEMBRANE WATERPROOF INSULATION FIGURE 1 FOUNDATION WALL BARREL' BELL BARRa SUPPORTS BELL AND SPIGOT CLAY PIPE ON HU SMALL EXCAVATION IN FILL FOR BaL CAULKINGs t RICH CEMENT FIGURE 2 Registers must be located before the dab is poured. Wooden forms life** those shown in Figure 3 are secured to the pipe by a wire wrapped around the duct. After the slab has hard ened, the form can be removed and an opening cut into the pipe with a heavy hammer or bar. Some contractors prefer to retain the wooden register forms in the slab for register mount ing frames. The Clay Pipe bell at the plenum should be butted firmly against the wooden forms of the plenum pit and the concrete poured around it. See Figure 4. "The pit floor is poured after the wooden form is removed. The moisture membrane must extend under the, pit floor. Recommended distance from the stfth floor to the top of the pipe bell is five inches. Clay Pipe in the Perimeter Loop should be installed so that the top of the bell closest to the perimeter will be \.Vi inches below the surface. Feeder ducts should elope down ward toward the plenum, so that the top of the bell next to th*> plenum wiU be five inches below the floor slab surface. See Figure 5. All Clay Pipe joints must be waterproof. Care must be taken when the slab is poured not to puncture the moisture barrier or didodge th& ducts. Wheelbarrows should not be moved over the ducts without suitable planking. National Clay Pipe Manufacturers, Inc. Washington 6, D. C. PIPE BUTTED 1- WOOD TO BE REMOVED l J_______ PIT FLOOR TO BE POUREDy AFTER FORM IS REMOVED' Figure 3 : MOISTURE . MEMBRANE * A strip of mesh should be placed over the top of the ducts to give added strength to the slab. Mesh may be extended over the entire slab at the contractor's discretion. Perimeter insolation--Perimeter insulation material should have not more than 0.40 Btu conductance at 70" F per square foot per hour per degree temperature difference. The material must be moisture proof, vermin and insect proof, and resistant to deterioration from contact with organic ma terials in the ground. If the perimeter insulation is installed on the exterior of the foundation wall, it should be protected against damage- If installed vertically, it should extend down ward not less than 18 inches and in extremely, cold flimtiM down to the frost line. Care must be taken not to rip or punc ture the insulation material during installation. All openings and punctures should be closed with a suitable compound. Fill placement--The coarse granular fill used under the con--- crete floor slab must consist of 4 to 6 inches of coarse material of uniform rise, preferably ranging from Yt to 1 inch. It is recommended to use gravel, crushed stone, or ^lag that has been passed over a coarse screen. The material should be free of "fines" to insure maximum volume of air space in the fill. Sand, unscreened gravel, rock, or cinders should not be used. Cinders will pulverise in due time and their corrosive action may damage plumbing and utility lines. The fill should be distributed and leveled over the entire floor surface. After the fill has been leveled to a desired.grade, it should be thoroughly compacted. Trenches--Trenches should be of sufficient depth to accom modate the heating duct with 4 inches of coarse fill under neath it and a strip of moisture" barrier laid on the top of the fill the entire length of the trench. The moisture barrier should be lapped at least 4 inches over the adjacent sections. The duct should be laid directly upon the barrier and gravel should be used to level and support the duct. The trench should be partially filled with gravel after the ducts are in stalled, aligned, and jointed. Slab pouring and caring--Concrete must be made with du rable, well-graded aggregate and should contain not more than 6 gallons of water per sack of cement, including the mois ture contained in the aggregate. When using average moist sand, no more than 5 gallons of water per sack of cement should be added. The mix should consist of 1 part Portland cement to 2V* parts of fine aggregate well graded in sues from 54 inch down, and 3 parts of coarse- aggregate well graded in rises from 54 inch up to 1 inch. Concrete should be placed and compacted thoroughly by vibrating or by tamping and spading. After the concrete is properly tamped, it should be screened to grade. . Concrete should be worked with a wood float, taking care to compact the surface properly. Depressions inequalities of any kind should be avoided. After the concrete has hard ened sufficiently to prevent fine material from working to the top (this will be indicated by the disapearanoe of "sheen" or shiny fihn of water on the surface) it should be steel-troweled, but excessive troweling should be avoided. Concrete should be kept moist for at least 2 days. If the finished floor is to be exposed concrete, at least 5 days of moist curing is required. The floor slab should be covered with moist burlap, canvas or waterproof concrete curing paper during the curing period. A full 28-day aging period should elapse before heat is in troduced into the slab. The heating duct air temperature should be raised gradually during the first 96 hours of operation. Too rapid drying of a "green" slab may result in cracked concrete. BELL 1W BELOW SLAB SURFACE o-fi o'Uq- : : is-y %: {OJ ~---------- f]---------- * V* BELL 5" BELOW SLAB SURFACE - l'/ S/yk, bell CLAY PIPE CLAY PIPE MOISTURE MEMBRANE Figure 5 FURNACE PLENUM a 318 ^fitvAMERiCAN-^tandard Seeling Systems American Radiator & Standard Sanitary Corporation, New York 18, N. Y. Boiler BOILERS--ralings, applications, fuels Net Ratings - " Fuel 1. G-2* 2. G-4* 3. G"G* 4. Areoleader* B. Arcoliner* . Oakmont* 7. A-5* . a. #2 Redflash 9. Severn* to. #3 Redflash It. A7 12, Exbrook 150-750 450-1,500 1,625-13,458 --. 303-588 447-900 815-2,594 769-1,794 456-869 1.503-2.400 2,707-6,949 863-1.938 36-180 108.0-360.1 390.1-3229.8 75.0-129.8 72.8-141.0 107.3-216.1 195.8-622.7 184.7-430.5 109.5-208.6 360.6-576.0 649.7-1667.7 207.1-465.1 Smaller homes, with or without basements Larger homes, small commercial Medium to very large buildings Smaller homes, with or without basements Smaller homes, with or without basements Larger homes, small commercial Larger homes and buildings Medium to very large buildings ' Larger homes, small commercial Medium to very large buildings Medium to very large buildings Larger homes and buildings Gas-all types Gas-all types Gas--all types Oil Oil Oil Oil Hand fired All fuels . All fuels All fuels ' Stoker `Cast Iron sections of hot water boiler guaranteed 25 years in residential applications ATn*riffln-fifcnriflTri hnilwa are designed for maximum efficiency in a minimum of space. They are noted for thfttr dependability and durability, which is achieved partly through their use of corrosion-resistant cast iron sections. Many are available with tankless waterheaters. arcopume oil burner--Model PH8--Newly de signed inrwr assembly results in efficient, quiet opera tion and dean flame. Four disk-turbulator combinations provide an efficient firing range from 0.65 to 3.00 gal/hr. Hanger, pedestal and flange mountings. Tube lengths from 5" to 23". Other models designed for efficient operation from 0.70 to 7.00 gal/hr. . * American-Standard, Plumbing & Heating Div. 319 1. heatrim baseboard panels--Nonferrous panels provide convected and radiant heat with forced circulation hot water systems only. Adaptable to mainless or series loop installations. Available in 4, 5, 6 and 8-ft lAngtha. Two models: 6"-high Model L and 10"-high Model H both available with H" or 1" dement. 2. radiantrim baseboard panels--Replace ordinary baseboards. Cast iron panels provide all the advantages of convected and radiant heat. Model 10: 10H" high for forced hot water or two-pipe steam. Available in 12, 18 and 24" lengths. Sheet-metal accessories available for complete in stallation. Model 8: 8" high. Available in 12 and 24" lengths. . 3. convectors--With cast iron (Arco) or non-ferrous (Multifin) heating elements. Styles and sizes for every need. Special designs for hospitals, institutions, etc. MultiGn Type K (shown) available in 68 packaged stock sizes. a. radiators -- SUNRAD: Recessed or free-standing. Needs no en closure. Two sizes: 5" deep x 20" high, and 7M" x 23". Inlet grilles if desired. ARCO: Highly efficient, slim-tube radiators. Available in four widths--3, .4, 5 and 6 tubes--and four heights--19", 22", 25" and 32". PEERLESS: Cast iron radiators for economical heating where floor space is at a premium. May be installed on walls, ceilings or hanging from girders. Available in 2 sizes, 8 and 11 sq. ft. per section. s. TYPE IO remotaire room conditioner--Year 'round, central plant air conditioning for homes and small commercial buildings; Individually controlled room units recess into walls between studs. Units cool and heat by passing air over finned coil supplied with water from central chiller and boiler. Quiet fan motor in each unit. 150-cfm unit (shown) 24" high, 6" deep and 16" wide; 300-cfrn unit 32" wide. e. type 20 remotaire room conditioner -- R^note-type vertical unit provides year 'round hydronic air conditioning for multiroom instal lations such as office buildings, hotels, apartments and hospitals: Features individual room control. 200, 300, 400 and 600 eftn sizes--all 9" thin--for free-standing, partially and fully recessed installation. Test-rated capacities. type 30 remotaire room CONDITIONER--Horizontal-style hydronic unit. Installed overhead, exposed or concealed: Four sizes: -- 200, 300, 400 and 600 efin--three models to meet all design requirements. B. TYPE 40 REMOTAIRE ROOM CONDITIONER-- ThrOUgb-the-wall-type year 'round heating-cooling unit has a compact self-contained refrigeration circuit- Connects to two-pipe steam or hot water system or, equipped with integral electric heating coil. May be installed room or floor at a timo with out disturbing normal operations of a building. One unit can.heat .a room while another cools adjoining room. Two capacitysizes-8200and 11000 Btuh. . packaged water chillers. Models BCS and ADS--Central chilled water source for medium- and large-size air conditioning systems. Model BCS (shown) in 4 sizes, 7.5 to 20 hp; Model ADS (direct drive) in 8 mw**, 25 to 125 hp. Completely packaged unit includes compressor nnH motor, evaporator, condensor, heat exchangers, controls, piping, framework. Model BCS tested and shipped with operating charge of refrigerant; Model ADS with holding charge. #320 ] 3 < 8 * s I; H 11 Heating Systems Manufacturing Company Unit erm 708 S. Spring Ave. * St. Louis 16, Missouri HEAVY DUTY FORCED AIR HEATERS HEATING SURFACES--Large, eiliptically shaped stainless steel combustion cham ber. Four complete passes of flame across air stream insure maximum heat extraction. One complete pas occurs in combustion chamber, with 3 separate passes through secondary heat exchanger where specially designed Turbolators swirl the hot gases. LOW INSTALLATION COST--Packaged, self-contained--requires connections only to fuel, power and exhaust. APPROVED BY AMERICAN GAS ASSOCIATION AND LISTED BY UNDERWRITERS LABORATORIES--All control systems approved by Factory Mutual Insurance Companies. 10-YEAR WARRANTY---All parts in direct contact with flame carry standard 10-year guarantee. BURNERS--Power type and available for oil, or combination gas-oil. Combination burners can effect immedi ate change-over from one fuel to another. Controls available for on-off control, high- low fire, or full burner modulation. Complete electronic protection provides power and fuel shut-off if Same fails. Heaters can be located on floor, qr horizontally or verti cally suspended from ceiling. Radiation shields reduce radiation and transmission losses, raring temperature does not exceed 10 deg above ambient temperatures. CAPACITIES___The right sixes have outputs of 400,000 to 2,000,000 Btu/hr. STAND-: ARD FAN CAPACITIES--Range from 4900 to 24,500 cu ft per minute. } JkrlLm CONVECTORS Rounded comers and edges enhance safety and appearance. Cabinets are ruggedly constructed. Front panels are reinforced with formed edges and channel stiffeners welded to the back side. The heating elements are for use on all hot water and two-pipe, steam systems. Constructed with copper tubes and aluminum fins, with the tubes hy draulically expanded into the fin collars. Available in floor, wall or recessed cabinets and standard or heavy duty institutional construction. PROPELLER FAN UNIT HEATERS Airtherm Horizontal and Vertical Unit Heaters are available in a total of 46 Standard and Low Outlet Temperature Models. Basic capacities range from 18,600 to 555/XX) Btu/hr, offering a selection to meet every job requirement. The coils are con structed of copper tubes, aluminum fins and steel headers. Tim tubes are expanded into the fin collars with 2jOOO lbs hydraulic pressure. The coils are tested with 500 lbs hydrostatic pressure. are made of heavy gage steel, phosphatized and finished with attractive gray-green enamel. Jkrlkerm CABINET UNIT HEATERS Feature efficient direct-drive power assembly with aluminum centrifugal fans and permanent split capacitor motor. The cabinets ore made of 16 gage steel, reinforced with angle and rhsnnt>* stiffeners, phosphatized and finished with attractive gray-green enameb Coils are constructed of copper tubes, aluminum fins and steel headers. Avail able in g models with basic capacities ranging from 375 to 1,630 cfm and 25,100 to 124300 Btu/hr. Units are offered for Floor, Wall or Ceiling mounting and in exposed or recessed cabinets. ____ CLASSROOM HEATING AND VENTILATING UNITS Feature functional design for hearing and ventilating classrooms and similar spaces. Damper is arranged to provide from 0 percent to 100 percent fresh air. Damper can be operated manually or automatically by application of temperature controls. The cabinets are constructed of 16 gage steel, well reinforced, phosphatized and attractively finished. Adequate end pockets for piping and controls. Coils are made of copper tubes, aluminum fins and steel headers. Power assembly is efficient direct drive with aluminum centrifugal fans and permanent split-capacitor motor. Offered in 4 capacities, 375 to 960 cfm. JlirtLnn AIK CONDITIONING UNITS Airtherm Air Conditioners provide healthful all season conditioned air comfort using a central source of chilled water for cooling and hot water for bearing. Designed for ffrhin-niHifymg, ventilating, filtering and introducing outside air in new or existing buildings, such as offices, hotels, apartments, motels, schools, churches and hospitals. The units are available in 4 types, for exposed floor and veiling mounting and (or con cealed floor and ceiling installations. Offered in 4 models ranging from 220 to 600 cfm and Vi to 2 tons nominal cooling capacity. _AA*m CENTRIFUGAL FAN UNIT HEATERS Designed to deliver a large volume of air at proper velocity and temperature through outlet nozzles or through a central duct system for hearing and ventilating all types of institutional, industrial and commercial buildings. Available with mixing box and dampers, face and by-pass dampers, filter section and jpmlated discharge plenum. Three types of coils are available, hot water, standard steam and steam distributing tube. The units are offered in 8 models with basic capacities ranging from 1300 to 22/X cfm and 95,000 to 1,440.000 Btu/hr. Heating Systems B,iu,, 321 BOILER ENGINEERING & SUPPLY CO., INC. PhoenixviUe, Pa. A HALF CENTURY OF BOILER MANUFACTURING EXPERIENCE Continental AUTOMATIC BOILERS BOILER-BURNER UNIT: COMPLETE -- AUTOMATIC -- ECONOMICAL CONTINENTAL Automatic Boilers, fully-equipped for firing oil, gas, or for in terchangeable oil or gas firing, generate steam at a guaranteed efficiency of not than 80% of their conservative ratings. Units are shipped complete with wiring, glass fiber insulation, metal jacket and paint finish, ready for service connections. No special stack or foundation is needed. Necessary trim and fittings are supplied, and unit is mounted on structural steel base. BOILER: SIMPLIFIED -- RUGGED -- ACCESSIBLE Lower fuel and maintenance costs and longer service life are assured by simplified two-pass design and CONTINENTAL'S unique "Spinning Gas" technique, which imparts a spiral motion at high velocity to the gases in the tabes and results in.a high rate of heat transfer. Boiler Series F has five square feet of heating surface per horsepower. Built-in steam separator assures 99% dry. steam. Hinged front and davited rear doors give easy Racced CONTINENTAL Boiler Dengs 40 HP CONTINENTAL Beflcr, inuid for firing light ofl. to heating surfaces. No refractory or brick-work needed, despite high furnace temperature and low stack beat. Boilers designed and built in accordance with ASMS code requirements. BURNER: CLEAN -- RELIABLE -- EFFICIENT Simple, nigged burner, of pressureatomizing type, produces uniform, highly radiant flame for oil-fired burner. For gas burner, fuel is mixed with air at point of ignition; baffle-ported nozzle ends dog ging or flashback. Blower drive is stand ard 1800 RPM motor, for forced draft at' correct pressure and volume for most ef ficient combustion. CONTROLS: MODERN -- AUTOMATIC -- DEPENDABLE Control system, designed to meet Un derwriters' Laboratories and Factory Mutual requirements as well as all local and national codes, provides such safe guards as electronic monitoring of flame, immediate shutoff and purge of burner after flame failure, low water cutoff and feed water control, front-panel signal lights. 20 TO 600 HP STEAM ... 15 TO 250 PSIG HOT WATER . . . LOW OR HIGH TEMPERATURE ON-OFF, LO-HI-LO, AND MODU LATING CONTROLS OIL, GAS OR COMBINATION FIRED Ten Reasons Why It Pays to Buy a CONTINENTAL Automatic Boiler Guaranteed 80+% efficiency... Firetested before shipment... Range, 20 to 600 HP. Simple, practical two-pass design, for uniform flow of combustion gases through all return tubes. Maximum radiant heat transfer achieved by "Spinning Gas" technique for thorough mixing of sir and atomized fueL Higb-CO* and low-temperature stack gases--proof of high combustion ef ficiency. Free, rapid water circulation, to im prove beat transfer, keep heating sur faces dean. e Easy access to furnace and all return tubes. Refractory baffles and brick work are not required. An engineered product, with every part designed for simultaneous operation and maximum' efficiency with every other part A single source of responsibility for the trouble-free performance of each com ponent. Continental Boilers have received world wide acceptance by those who are most insistent in requiring silent operation, namely Hospitals, Schools, and Churches. . A nationwide network of factory-trained servicemen, available through your local CONTINENTAL Boiler distribu tor.  322 Heating Systems - CRANE CO. General Offices: 836 South Michigan Avenue, Chicago 5, Illinois Nationwide Service Through Branches Wholesalers, Plumbing and Heating Contractors BOILERS BASEBOARD, RADIATORS, AIR CONDITIONERS, VALVES, FITTINGS, PIPE, WATER AND STEAM SPECIALTIES, CONTROLS AND PLUMBING MATERIALS Crane--a single source for everything in heating CRANE CAST IRON BOILERS A complete line available for the hydronics* field. (* Industry's new name for the science of heating and cooling with water.) Residential and com mercial boilers. Cast iron sections of all Crane Sunnyday residential hot water boilers carry a 20-year guarantee. RESIDENTIAL BOILERS Crane Snnnyday Seven. All new oil fired boiler. Available in 2 sizes, pre wired, pre-asscmbled, ready for installation. Available with tankless water heater. Net I=B=R ratings: 78,000 and 117,800 Btu/hr. (water) Crane Sunnyday 15. Saves up to 15 percent on fuel. Four sizes, oil or gas fired. Two sizes available assembled and wired. Net 1--B=R rating: 66,800 to 156,000 Btu/hr. (water, oil fired) Crane Sunnysaver 15E. New replacement boiler for customers who al ready have good burners and controls. Compact, easy to install. Attractive, fully-insulated extended jacket. Four sizes, Net I=B=R ratings: 66,800 to 156,000 Btu/hr. (water, oil fired) Crane Sunnyday 2WG. Only 33 inches high. Four sizes, designed espe cially for gas. Two sizes available fully assembled and wired. A.GA. input: 70.000 to 210,000 Btu/hr. Gross A.GA. output: 56,000 to 168,000 Btu/hr. Net rating: 42,000 to 126,000 Btu/hr. (water) Crane Sunnyday 20 "All Purpose". All-fuel boiler for home or small commercial steam or hot water systems. Net I=B~R rating: 100,500 to 245,300 Btu/hr. (water, oil fired) Crane Sunnyday 26. Gas fired hot water or steam boiler. Features tank less water heater on hot water models. New efficient ribbon burner. Equal ratings for all gases. A.GA. input: 200,000.to 450,000 Btu/hr. Gross A.GA. output: 80,000 to 360,000 Btu/hr. Net rating: 60,000 to 270,100 Btu/hr. (water) Crane Sunnysaver 26. New low-cost factory-assembled gas fired hot water boiler. Available in 3 and 4-section sizes. Tankless water heater available in 4-section model. A.G.A. approved for all gases. Gross A.GA. output: 80,000 and 120,000 Btu/hr. Net rating: 60,000 and 90,000 Btu/hr. COMMERCIAL BOILERS Crane Sunnyday 30. Medium size all-fuel boiler for small commercial steam or hot water systems (or large homes). 14-inch and 21-inch base for oil fired models. Net I=B~R rating: 225,100 to 843,200 Btu/hr. (water, oil fired) .. Crane Sunnyday 40. Gas fired boiler for large homes or commercial use. Patented staggered heat travel. For hot water or steam systems. A.GA. input- 350 000 to 2,380,000 Btu/hr. Gross A.GA: output: 280,000 to - 1,904,000 Btu/hr. Net rating: 210,100 to 1,478,000 Btu/hr. (water) Crane 41. All-fuel boiler for commercial, industrial, or institutional in stallations. Precision ground cast iron sections easily assembled. Net rating. 621,900 to 1,823,800 Btu/hr. (water, oil fired) Crane Sunnyday 60. Big 6-inch gas boiler. Steam, hot water, or large volume indirect water heating. A.GA. input: 625,000 to 5,000,000 Btu/hr. Gross A.GA. output: 500,000 to 4,000,000 Btu/hr. Net rating; 374,100 to 3.108.000 Btu/hr. (water) VALVES AND FITTINGS A complete line. All the necessary piping items for any hydronic heating system. .' i Sflfc Crone Co. 323 CRANE(SUNNYBASE PANELS Complete line of finned-tube residential radiation. Takes the place of woodwork. Saves space, leaves entire floor free for furniture. Sunnybase Type E. Copper tube, aluminum fins. Fins are specially cor rugated for rigidity and heat transfer efficiency. Free expansion of element is provided by electro-galvanized Silent-Glide Slide Shoes. Finished in stallation measures 22%2 x in. 3, 4, 5, and 8-ft lengths, complete accessories available. - Sunnybase Type F. Copper tube, aluminum fins. Corrugated construction gives rigidity and increased heating surface (over 4 square feet per lineal foot of baseboard). Sized-to-mate tube ends, jointed without couplings, minimize brazed joints and save fittings. Finished installation measures 2SA x 9%G in. Available in 4, 5, 6, and 8-ft lengths, with complete ac- CRANE SUNNYAIRE UNIT HEATERS ' Completely automatic, safe, economical. Easy to install and maintain. Gas, hot water and steam models available in full range of sizes. Sonnyafre Gas Unit Heater. 10 basic sizes. A.GA. approved. Designed for natural, manufactured, mixed, or LP gases. 25,000 to 200,000 Btu/hr. (input). Sunnyaire Hot Water and Steam Unit Heaters. 58 models. Type HV-- for both horizontal and vertical applications. Features wrap-around heat ing element. Capacities from 34,000 to 684,000 Btu/hr. Type H--for hori zontal applications. Features continuous tube heating element. Capacities from 15,000 to 335,000 Btu/hr. CRANE SUNNYAIRE CABINET HEATERS StranyaireHot Water and Steam Cabinet Heaters. A complete line of blow-through and draw-through types for all practical installations. 21 hot water models, 14 steam models with air capacities from 265 to 1005 cfm.. Heating capacities: 71 to 313 Sq. ft. EDR for steam, 9.1 to 65 MBH for hot water. CRANE SUNNYWALL COMMERCIAL RADIATION-- I = B = R RATED Two types of high-capacity, superior-quality commercial radiation: Cop per tube with aluminum fins, steel tube and steel fins. Full line of ac cessories and optional equipment. Sunnywall copper tube with aluminum fins. Ten types of heating ele ments. 700 to 3060 Btu per ft. (1 lb steam) 5 enclosure styles. Sunnywall steel tube with steel fins. Five types of heating elements. 890 to 3280 Btu per ft. (1 lb steam) 3 enclosure styles. CRANE AIR CONDITIONING Crane Stowaway Air Conditioner. 2 and 3J4-hp units. Compressor, con denser, blowers and evaporator all in one cabinet. Available with pre fabricated Fiberglas ducts. ' Crane Packaged Air Conditioners. A new fine for offices, restaurants, banks, stores and small factories. Includes 3, 5, iVi, 10 and 15 ton units with front grille or top duct discharge. Water condensing unite are factory assembled, wired, charged and tested. Air condensing units have receiver ready for addition of remote air-cooled condenser. All models fully war ranted. ' 1: t ! i  324 Heating Systems B*lbn< BadlalM< Tiba, Tuia ' 'puimAam/'^iporcitiUmp -^SsSSp' HEATING & COOLING DIVISION IRVINGTON, NEW YORK Tbere's a Burnham for Every Purpose--Write for Descriptive Catalogs A. Burnham Caat-Iron BASE-RAY Radiant Baseboard Two Sizes. No. 7 and No. 9 I->B*R Rating per sq ft tor No. 7 is 235 and for No. 9 is 3.45 per sq ft Tappings yK id. top and bottom. Sections come in 12. 18 and 24 ia. lengths. New matching sheet metal baseboard extensions and accessories available. . F. BURNHAM JUBILEE Wet Base Cast-iron Oil Boiler-- Vertical Flue Travel. Available in 7 sixes for steam, 320 to 955 sq ft and 8 sizes for water, 445 to 1525 aq ft. An overall . range of 9 sixes. Flush and extended Jacket models. Provided with built-in hot water coils if desired. G. BURNHAM JUBILEE PAK--Available in 5 sixes. 445 sq ft to 1010 sq ft water only. Shown with controls ana wiring factory installed. Delivered crated ready for easy installation. B. BURNHAM RADIANT RADIATORS--Two heights 20 and 23 in. Ratings 2.25 sq ft per section and 3.40 sq ft per tec- tion respectively. C. BURNHAM SLENDERIZED RADIATORS--Three to six tubes in four heights 10 in. to 32 in. Ratings are from 1.6 sq ft per section to 3.7 sq ft per section. H. PACE-KING BOILER--Exclusively oil fired for larger buildings. Vertical Sue design . . . low stack temperatures. Tankless hot water heaters with capacities from 6 to 15 gal. 14 models from 1205 to 4500 sq ft for steam and 1925 to 7200 sq ft tot water. Built according to ASMS code and 7--B--/? rating and testing code. D. HOLIDAY Cast-Iron Boiler #60 ia A.G.A. approved for manufactured, natural, mixed or LP gases and /=B=R ap proved and rated. Capacities for water from 300 to 1100 sq ft and for steam 190 to 690 sq ft. Can be equipped with built-in year 'round tankless hot water coil, five sixes aa HOLIDAY- PAK Factory assembled. E. New HOLIDAY Cast-Iron Boiler #70 is A-G.A. approved for manufactured, natural or mixed gases and is R ap proved and rated. Capacities are for water 600 to 2?00sq ft and for steam 375 to 1690 sq ft. Can be equipped with tankless built-in hot water coil. I. WELDED STEEL Boiler--Compact type--Capacities from 2600 to 35000 sq ft for steam and 4680 to 56000 sq ft for water, EDR. Net SBI ratings. Furnished for coal, oil or stoker firing. J. SCOTCH TYPE Steel Boiler--completely packaged with combustion unit or unpackaged. Net SBI capacities from 2600 to 35000 sq ft EDR steam and from 4680 to 56000 sq ft EDR water. Also we build these up to 4000 sq ft of heating surface. Heating Systems Hrirwie National-U.S. Radiator CORPORATION HEATING AND AIR CONDITIONING DIVISION fehiatowB. Pcamylrtnii Cast Iron and Steel Boilers * Baseboard * Convectors Radiators Fintube Unit Healers * Furnaces * Oft and Oas Burners * Air Conditioning * Accessories Nationwide distribution through Branches, Wholesalers, Plumbing and Heating Contractors NATIONAL-U. S. CAST IRON BOILERS AND UNITS (FOR ALL FUELS) 325 "UB" Gas Boiler "16C" Gas Boiler "22" Gas Boiler "66" Gas Boiler CAST IRON BOILERS AND UNITS--RATINGS, APPLICATIONS, FUELS BOILER OR UNIT NET I-B-K RATING BTU/HR STEAM ' WATER NO. OF KTTFg APPLICATION Sunray IV Packet ' Sunray IV Oil Heating Boiler & Unit Comfortline Boiler and Oil Heat ing Unit Premier Chi Heating Boiler ("25B" Series) t" Senes All-fuels Boiler "2G' Senes Chi Heating Boiler and 66,800 66,800 75,000 203,300 109,500 109,500 158,300 219,100 85,500 565,600 234,100 234,100 4 6 Small to large sire residential installa- 2 Small to medium residential 6 Large residential to email commercial 6 6 Medium to large size residences "37" Series All-Fuels Boiler 232,600 638,200 9 Large residential and small eom- 3/" Senes Oil Heating Unit 232,600 636,200 9 Large residential and small com- 47" Series All Fuels Boiler 622,700 1,823,000 10 Institutional, commercial and indus- 4G' fcienes Oil Heating Unit 622,700 1,537,300 8 Institutional, commercial and indus- liB" Senes Gas Boiler' 15C" Series Gas Boiler' 32 Series Gas Boiler* 33 Senes Gas Boiler* 44". Series Gas Boiler* lw> Senes Gas Boiler* 27,000 87,000 38,000 97,500 121,600 450,100 108,000 .565,600 107,300 259,600 486,100 3,416,100 7 11 6 6 9 Large size installations 20 Institutional, commercial and indus trial installations * A.a.A. Appretui. FUEL Oil Oil Oil Oil All Fuels Oil Ail Fuels Oil All Fuels Oil All Gases  326 National-U- S. Radiator Corp. Healing Systems NATIONAL-U. S. STEEL BOILERS AND UNITS--(ALL FUELS) * A>^>utua( National-U. S. Radiator Corp. *327 Mark 11 Packet Mark III Packet Model U Packet Sentinel Series Commander Serie. Boiler Boiler CTj-pe SN * SF) "King of Scots" Boiler-Burner Unit STEEL BOILERS AND UNITS--RATINGS, APPLICATIONS, FUELS Mirk II Packet (OP-15-WE) Mark II Packet (GP-15-WE) Mark III Packet Model U Packet (OU-19-W) Model U Packet (GU-19-W) Sentinel Steel Boilers and Units (17', & 24', Series) Pnmmander Steel Boilers (28 , ry.mmknder Steel Boilers Units (26*, 29', 39', 4 Series) , Commercial Steel Boilers and Scotch Type Boilers (SN-Natural Draft) Scotch Type Boilers (SF-Forced Draft) , ,, ., Scotch Type, Packaged Boiler- Burner Units * t/att*factBTtr* CtrtifM Ratinp. SB! NET RATING STEAM WATER 74,000 87,000 87,000 78,000 87,000 243,000 243,000 189,000 1,350,000 1,350,000 813,000 1,217,000 1,969,000 1,969,000 9,450,000 9,950,000 15,300,000 15,300,000 NO. OF SIZES APPLICATION FUEL 1 Small to medium homes Small to medium homes oa Gas 4 Small to medium size residential in- 00 1 Rmall to medium size residential in- Oil 1 Small to medium size residential in- Gas 4 Small to medium size residential in- Oil 18 Large residential to small commercial Oil, Gas or, Stoker 13 Large residential to small commercial Oil or Gas installations 16 Institutional, commercial and indus- Gas, 00 Stoker or hand 13 Institutional, commercial and indus- Oil or Gas 13 lastitutional, commercial and indus- Oil, Gas, Gas00 13 Institutional, commercial and indus- Oil, Gas, Gas- trial Oil v National-U. S. Heat Distributors Baseboard--three types available: Sunray (east iron). Art Comfortline (standard capacity, non-ferrous) and Floorline Unit Heaters--for hot water and steam also for gas firing-- both types in a wide range of sues (high capacity, non-ferrous). Convectors--two types: Aero Convectors (cast iron) and Art Convectors (non-ferrous). For hot water and steam systems. Fintube Radiation--available in two types: steel tubing with steel fins and copper tubing with aluminum fins. Variety of covers can be furnished. Numerous types of enclosures. . Radiators--three types available: Thin-tube are compact and slender; Sunray with solid front and Wall for versatility. Conversion Burners and Heating Accessories--oil and gas conversion burners for boilers and furnaces. Complete line of heating accessories for convenient one-source service. CAPITOJLAIIiE AIR CONDITIONING AND WARM AIR FURNACES 1. Residential and Commercial Packaged Air Conditioners . . . water or air cooled ... 3 to 20 tons. 6. Horizontal Fan-Coil Unit, Model HRZ ... in 300 to 17<50 CFM ... for surface or concealed installations. 2. Residential Fan-Coil Unit,'Model VRS . . . for heating and cooling ... in 150 and 300 CFM Biies . . . available for recessed or free standing installations. . 3. Vertical Fan-Coil Unit, Model VER . . . for heating and cooling ... in sixes of 200, 300, 400 and 600 CFM ... for concealed or free standing installations. 4. Gas or Oil Fired Steel Furnaces . .. residential and small * commercial . . . ranging in rise from 64,000 to 200,000 . Btu/hr output. 7. Hi-Cap Furnace . . . for gas, oil or coal firing . . for commercial and industrial installations. . . output up to 1,000,000 Btu/hr... suspended models also available. 8. Model CEN-IB . . . self-contained packaged air condi tioner with built-in evaporative condenser ... ranging from 7)4 to .OO.ton capacity. 9. Model CEN-IW . . . self-contained packaged air condi tioner with water-cooled condenser . . . ranging from 7M to 60 ton capacity. 10. Model CHL-IW. . . packaged water chiller with watercooled condenser . . . ranging from 7)4 to 75 ton capacity. 5. Horizontal Fan-Coil Unit, Model HER ... in sizes of 200, 400 and 600 CFM . . . for concealed installations with and without duct work. 11. Model CHL-IE . . . packaged water chiller with built-in evaporative condenser . . . ranging from 7)4 to 75 ton capacity.  328 Pacific Scotch Type Boilers PaciGc "LoSet" Boilers Heating Systems MfMUt DIVISION Mteltr Ctrpttilpm JOHNSTOWN. PENNSYLVANIA Sales Offices in All Principal Cities SBI TABLE 1 BOILERS A Complete Line of Low-Pressure Steel Heating Boilers For Commercial Application All Pacific Commercial Boilers are built in conformity with the ASME Code for low pressure heating boilers and are rated in accordance with The Steel Boiler Institute Rating Code with the exception of the Scotch Type Boilers for forced draft firing which have Pacific certified ratings. PACIFIC STANDARD FIREBOX BOILERS Pacific Standard Firebox Boilers for Stoker, oil or gas firing are built in capacities of SBI rating from 2,840 to 64,280 sq ft for steam and from 4,540 to 102,850 sq ft for water. Design is of two types: Low Water Line and High Firebox. Pacific Direct Draft and Smokeless Boilers for .coal firing are built in capacities of 2,200 to 35,000 sq ft for steam and in corresponding capacities for water. PACIFIC SCOTCH TYPE BOILERS Pacific Scotch Type Boilers are available for natural or forced draft firing with oil or gas. The Natural Draft Scotch Type Boiler ratings range from an SBI rating of 5,800 to 64,280 sq ft steam and 9,280 to 102,850 sq ft water. The Forced Draft Scotch Type Boiler ratings are manufacturers' certified rating and range from 1,969,000 to 21,775,000 Btu/hr. Both series ap plicable for steam and water heating. PACIFIC "LOSET" BOILERS Pacific "LoSet" Boilers for oil firing are available in 18 sizes with capacities of SBI rating from 4,500 to 64,280 sq ft steam and 7,200 to 102,850 sq ft water. Unique "LoSet" design requires minimum headroom without sacrificing boiler efficiency. ' PACIFIC SPLIT-FIREBOX BOILERS Pacific Low Water Line, High Firebox and LoSet Boilers are available in three sections--shell, firebox and base--and can be moved through mini mum building openings. Where necessary, Pacific fireboxes can be split (as illustrated) to allow the boiler to be taken into the building in four pieces, through most doors, windows and hallways. No cutting or welding is required in assembling Pacific Boilers of this type. Descriptive bulletins on Pacific Commercial Boilers will be nulled on request . S. Ktditlt Cr|ruiM JOHNSTOWN. PENNSYLVANIA Sales Offices in All Principal Cities 329 MtMtts SBI TABLE 2 BOILERS . A Complete Line of Residential Steel Boilers for Coal, Stoker, Oil or Gas Firing All Pacific Residential Boilers are built in conformity with the ASME Code for low pressure heating boilers and are rated in accordance with The Steel Boiler Institute Rating Code. . PACIFIC "PLATE FLUE" BOILERS Pacific "Plate Flue" Boilers are designed for oil or gas firing and are built in 4 sizes. SBI net ratings range from 108,000 to 243,000 Btu/hr for steam and water heating. They are available with either flush or extended jackets. k ..... PACIFIC "PLATE FLUE" OIL HEATING UNITS Pacific "Plate Flue" Oil Heating Units are boiler-burner units designed for steam or hot water heating. Furnished with pre-cast combustion cham ber, matched oil burner and automatic controls. Ratings are the same as for "Plate Flue" Boilers. Available with flush or extended jackets. Pacific "Plate Flue" Oil Heating Units PACIFIC SERIES "700" BOILERS (3-pass Design) Pacific Series "700" Boileraof the 3-pass design (firebox and 2 passes of tubes) available for automatic and hand firing, also as oil or gas boilerburner units. Designed for large residential installations. SBI Net Ratings range from 180,(W0 to 595,000 Btu/hr in 7 sizes for hand firing and from 297,000 to 810,000 Btu/hr-in 7 sizes for automatic firing for steam and water heating. Available,with flush jacket. Boiler-Burner Units Automatically Fired Boilers PACIFIC SERIES "700" BOILERS (2-Pass Design) Pacific "700" Series Boilers of the 2-pass design (firebox and 1 pass of tubes) available for automatic and hand firing, also as oil or gas boilerburner units. Designed for large residential and small commercial instal lations. SBI Net Ratings range from 945,000 to 1,350,000 Btu/hr in 4 sizes for steam and water heating and for automatic firing. Hand fired SBI Net Ratings range from 690,000 to 990,000 Btu/hr. Available with flush jacket. Script!., bulletTM on P.cific Ro.id.utLI BoilTM -III b. . mailed on request Boiler-Burner .Units Automatically Fired Boilers  330 Heating Systems THE PEERLESS HEATER COMPANY Boilers Cast Iron Hot Water Steam Vapor Boyertown, Pennsylvania DEERI CCC Furnaces Automatic Winter Air Conditioners Manufacturing Division and General Offices_____________________________ BIG SERIES 150 55 GAS FIRED SIZES Rated 70,000 Btu to 6,400,000 Btu input/br. For close adherence to specifications. Cast Iron Boiler Gas Fired SERIES 150 High capacity gas fired boiler built to rigid speci fications, designed for industrial use with Natural, Manu factured and Mixed gases,' LP and LP Gas-Air Mixtures. Incorporates multiple pilot line, raised ports, cast iron burners, horizontal to vertical due collector plus additional quality features. 33 Sizes. A.GA. rated GQQfiOO to 5,400,000 Btu/hr input. Hot Water Steam and Vapor. Peerless "SUPEK" 13 gas presage, <* "H" block construction with 6 in. ports and tappings- strength and efficiency are. attained. SERIES 50 Recommended for industrial and large residential installations. Incorporates the same quality features of the 150 SERIES with lea capacity and more compactness to enable installations where limited space is a requisite. The latest ad vancements and design are the features in the SERIES 50. 7 Sizes. A.GA. rated 350,000 to 650,000 Btu/hr input. Hot Water, Steam and Vapor. ` All Series 50 Cast Iron Boiler sections are preassembled in blocks of 3. 4 and 5 sections to effect a savings and assure posi tive installations. Section blocks are factory hydrostatically tested at pressures up to 200 lb. '- The PEERLESS Series 50 and 150 introduces important advances in engineering research, modem design, new materials, manu facturing methods aad boiler setting-up procedures. PEERLESS'S world famous master foundry workers and engineers have intro duced sensationally new concepts in CAST IRON BOILERS, the lifetime metal. With the introduction of the Series 50 and 150, PEERLESS now offers 55 sizes of Gas Fired Boilera to meet every installation requirement frtan 70,000 to 5,400,000 Btu input. A.OA ,BJt Btlkn, Cut bw % The Peerless Heater Co. CAST IRON GAS AND OIL FIRED BOILERS 331 Series "TG" 8eries "G" Series "TO" Series "TOU" SERIES "TG" Gas fired cut iron boilers meet most residential requirements, including instantaneous domestic copper water heater. Available in deluxe flush and deluxe extended type jackets. SERIES "G" Gas fired boilers incorporate the same features as the "TG" Series but do not have domestic hot water heater. Deluxe flush or deluxe extended jackets are available. Rugged cast iron construction for long life. Factory assembled block sections for fast set-up- Deluxe two-tone green enameled steel jackets. SERIES "TG" A "G" 6 Sizes--105,000 to 291,000 Btu Input hr. A.G.A-. -rated. Steam Water and Vapor. SERIES "TO" Oil fired boilers with all Peerless water tube features: Factory assembled sections, domestic hot water heater op tional. "0" Scries available without domestic water heater. ' SERIES "TOU" Oil fired boiler is the same as Series "TO" but includes Peerless Deluxe oil burner. Deluxe flush and extended jackets available. Peerless oil fired heavy duty residential heating boilers are made for homes of all sizes. 7 Sixes. Gross l -- B = R Output Btu/hr 93,000 to 234,000. Net Water Rating: 465 sq ft to 1170 sq ft. Net Steam Rating: 250 sq ft to 650 sq ft. PACKAGED OIL AND GAS FIRED BOILERS SPRITES "TOUP" Oil fired boilers are delivered completely crated with all controls. Factory assembled and tested to assure time saving installations. 2 Sizes. "TOUP"-l35A-W-Net Water Rating: 555 sq ft. "TOUP"-145A-W. Net Water Rating: 735 sq ft. DESCRIPTIVE CATALOGS QF SPECIFICATIONS, RATINGS AND DIMENSIONAL DRAWINGS OF PEERLESS BOILERS WILL BE MAILED UPON REQUEST. . SERIES "MM" (Mighty Midget) boiler with compact design for installations in limited space areas. White baked enamel. Com pletely assembled and crated. "MM" 70B-W, A.G.A. input 70,000 Btu/hr, 24 in. high. "MM" 95B-W, A.G.A. Input 95,000 Btu, 30 in. High. ,rMM" 120B-W, A.G.A. Input 120,000 Btu, 36 in. High. Oil Model Gas Model PEERLESS GAS AND OIL FIRED FURNACES Peerless fully automatic Oil and Gas fired furnaces represent advancements in Engineering, Performance and Design. A full line ennafltmg of 9 Series with 22 models provide in stallations for every type of home. Gas fired furnaces are rated 70/100-150,000 Btu/hr Input. Oil fired furnaces are rated 72,000-140,000 Btu/hr Output. The 9 Scries of Peerless gas and oil fired furnaces include 10 Models in the gas fired Series and 12 Models in the oil fired Series. Beries include HI-BOY, LO-BOY, GRAVITY, COUNTERFLOW and HORIZONTAL TYPES. Peerless warm air furnaces are completely assembled, wired and packaged at the factory for ease of installation. Specification sheets are available by writing The Peerless Heater Company, Boyertown, Pennsylvania.  332 Heating Systems PENNSYLVANIA FURNACE & IRON COMPANY Warren, Pennsylvania 316 North Pine Street . Pennco Cast Iron Gas Fired Boilers, Pennsylvania Forced Air and Gravity Furnaces, Floor Furnaces, Conversion Burners, Multitube Burners, and Cooling Equipment SERIES 6 PENNCO GAS FIRED BOILERS Thirty sizes, all gases, 400,000 to 4,400,000 input. Steam, water, vapor and volume hot water beating. ASM and A.G.A. approved. Twice tested to 200 lb hydrostatic {or work ing pressures of 15 lb steam or 80 lb maximum water pressure. Base is of welded steel, shipped assembled complete with manifold and safety pilot in place. . Horizontal draft diverters save head room. Vertical diverters ran be furnished upon request. Front rasing panel removable for convenience in cleaning. Draw bolts for easy assembly of section. Holding bolts keep sections metal to metal. Individual gas burner cocks for each section permit shutting off one or more burners and still maintain operation of the boiler. Boilers are equipped with gas actuated controls to permit operation in event of electric failure. Electric controls are also available. SERIES 3 PENNCO GAS FIRED BOILERS Fight, sizes for all gases. Inputs from 96,000 to 432,000 Btu. Steam, water, vapor and volume water heating. ASME and A.G.A. approved. Two tests of cast sections at 200 lb hydro static. Water boiler approved for 80 lb working pressure. Factory assembly of battery of sections. .Water leg sections provide increased efficiency. Hollow projections on sections increase area of heating surface for faster transfer. Boiler casing Standard type with controls exposed or DeLuxe type enclosing controls. Two-tone blue baked enamel finish. . ' Controls are gas actuated or electric types; factory assembled and fire tested. Color coding removes any guesswork during erection. SERIES 2 PENNCO GAS FIRED BOILERS Four sizes for all gases. Water operation only. Inputs 44,000 to 87,625 Btu. ASME and A.G.A. approved. Sections tested at 200 lb hydraulic pressure. . Approved for 80 lb working pressure. Cast sections shipped assembled. Adapted to heating of apartments, small homes, stores, and offices. Wet base and diamond shaped hollow projections increase efficiency. Choice of Standard casings for basement use or DeLuxe casing for installation in kitchens and other finished rooms. SPECIAL Stand-by controls to supplement natural or artificial gas with LP gas. ' Automatic operation of dual gas controls. By predetermined setting based on outside temperature operation will swing from natural gas to LP gas and return as weather changes. Ask for special bulletins. ' Heating Systems bibn, cin. The H. B. SMITH COMPANY, INC. Westfield, Mass. Branch Offices and Sales Representatives in Principal Cities A complete line of modem cast iron sectional boilers for residential, commercial and industrial heating and for domestic hot water supply. 333 SMITH "CENTURY" GAS BOILER, A.G.A. approved, for steam or . hoc water heating. Input ratings from 158,000 to 745,500 Btu. Combines latest features of gas boiler design. Available .with five *'*** of built-in tanIf domestic hot water heaters, capacities to 168 gaL and eight sizes of *nlrlg heaters, capacities to 8 gpm. Entire burner assembly mounted on . wrought iron frame with casters for easy removal. "100" & "2000"OILBOILER- BURNER steam or water units for homes and small commercial instal lations. Furnished with line of tank less heaters with capacities up to 8 gaL of hot water per minute. Net radiation to 1275 sq. ft. steam; 2210 sq. ft, water. SMITH-MILLS BOILERS, Series 15-20-25; capacities 200 to 2275 sq. ft steam radiation. This complete line of modem push nipple boilers is available in models for gas, oil, stoker or hand firing. Have provisions for built-in domestic hot water heaters and controls. MILLS WATER TUBE BOILERS, Series 24-34-44; capacities 900 to 13,380 sq. ft steam radiation. Independent header type construction. Tens of thousands are installed in. schools, hospitals, apartment houses, stores and ocher commercial and public buildings. Models for hand and all types of automatic firing. v SMITH HY-TEST BOILERS for hot water supply are furnished in several models, and many sizes for tank capacities to 20,000 gaL Con structed of the finest quality grey iron castings, these Hy-Test units are carefullytested at extremely high pressures before shipment. "42" & "60" SMITH BOILERS, may be used in batteries for hearing loads up to and over 100,000 sq. ft. steam radiation. Many of these large units installed in industrial plants furnish steam for processing require ments as well as for heating and domestic hot water. r 334 Heating Systems - - 111-- ^SPENCER^ H EATE R A PRODUCT OF AVCO MANUFACTURING CORF. ,tl,A.M5poRT PENNSYT-''^*1 Akron, Ohio Albany, New York Allentown, Pa. ' Atlanta, Ga. Baltimore, Md. Binghamton, N. Y. Boston, Mass. Buffalo, N. Y. Charlotte, N. C- Chicago, HI. Cleveland, Ohio Columbus, Ohio Dallas, Texas Dearborn, Mich. Dearer, Colo. Port Worth, Texas Greensboro, N. C. Harrisburg, Pa. Sales Represents) Indianapolis, Ind. Kal&masoo, Mich. Kansas City, Mo. Knoxville, Tenn. Los Angeles, Calif. Louisville. Ky. Minneapolis, Minn. Mt. Ephraim, N. J. Murfreesboro, Tenn. Nashville, Tenn. New Orleans, La. Newtown, Conn. New York, N. Y. Philadelphia, Pa. Pittsburgh, Pa. Racine, Wis. Richmond, Va. Roanoke, Va. Salt Lake City, Utah San Antonio, Texas Spokane, Wash. * St. Petersburg, Fla. Toledo, Ohio Washington, D. C. Portland, Ore. Blenheim, Ont., Canada STEEL AND CAST-IRON HEATING BOILERS FOR EVERY BUILDING ... FOR EVERY FUEL "LW", "A", "CP", "R". and Suburban Series fully approved by Steel Boiler Institute All products manufactured in strict accordance with the ASME code and carry the code seal. Every Spencer meets rated specifications, is easy to install* assured economical operation. "A" SERIES CAPACITIES 3,500 to 42,500 sq ft STEAM SBI RATING--A rugged, tough commercial and industrial heating boiler designed for f&st steam ing pr>H efficient operation. All sizes available with front head cuts for low-6et installations and with storage or instantaneous service water coils. . ' "CP" SERIES (OIL- OR GAS-FIRED) CAPACITIES 1,300 to 5,000 sq ft STEAM NET SBI RATINGS . 468,000 to M00,000 Btu GROSS OUTPUT--Incor porating a revolutionary refractory slab base and with either oil- or gas-burning equipment. Easy and quick to install. Low waterline for problem installations. . p*ibn, stcci . Spencer Heater 333 "LW" SERIES . CAPACITIES 2,200 to 42,500 sq ft STe/m SBI RATINGS--A patented, divided low- waterline boiler made in two watertight sections that need no welding on job. Designed to overcome prob lems in low head room, excavation and entry. Particu larly adapted for replacement installations. Available' with front head cut for extra, low-set installations. "R" SERIES . RESIDENTIAL STEEL BOILER CAPACITIES 320 to 1,100 sq ft STEAM, NET LOAD--SBI RATINGS--A ruggedly constructed, high-quality boiler for oil, gas, or stoker firing. Available with storage or instantaneous type service water coils in a wide range of capacities. Par ticularly suited for engineers and contractors who prefer to build their own design for heating installa tions. Available with both flush and extended model jackets. ' "RANCHER" CAST-IRON GAS BOILER CAPACITIES: 1G series: 40,000 to 128.000 Btu 2G series: 80,000 to 232.000 Btu A clean, neat compact design. Especially quiet in operation, using cast-iron burners with raised drilled ports. Also avail able with year-round domestic hot water coils. "SUBURBAN" GAS-AND OILFIRED PACKAGE UNITS CAPACITIES: 87,000, 108,000, 149,000 and 189,000 Btu--NET SBI WATER RATING--A compact, quality package unit designed for installation in kitch ens, utility or rumpus rooms.-Baked white enamel jacket. Completely wired and ready for installation... with volumes of year-round domestic hot water supply. SPENCER H CATE R s* fROOUCT Of AVCO MANUFACTURING CORF.y ,tl,Al*srofn pcnn5TivahV  336 Heating Systems CUJier*. Call It UJElL-fflcLAIN COmPANY General Sales Office: MICHIGAN CITY, INDIANA ' . ' Distributors in principal cities HR Heavy Duty Boiler for Horizontal Rotary Burners Special steel front plate and section simplify rotary burner installation. Large fire-box volume develops better combustion conditions--high base elimi nates high brick foundation. ASME constructed. Load range : Steam and Water 885, 200-2,942,500 Btu/hr. OB Oil Fired Boiler Cast iron boiler designed specifically, to bum oil with great economy. Can be in- , stalled on any type of floor--special base' plate allows free air circulation beneath boiler. Shipped completely assembled in cluding specially designed refractory combustion chamber- ASMB con structed. Load range: Net rating. Steam 68,000-88.000 Btu/hr.; Water 79,000-101,000 Btu/hr. B-HO-40 and 44 Heavy Duty Oil Fired Boilers For dependable, efficient operation in school, commercial and industrial instal lations. The burner and other compo nents are engineered to function as a unit. High base eliminates brick founda tion or pitting. New burner design asassures smooth, quiet starts. ASME constructed. Load range: Net l=B-- R rating. Steam and Water 667.700-1,897,500 Btu/hr. No. 82 Oil Fired Boiler and Oil Heating Unit Available as `'B" unit, including burner and combustion chamber; "A" unit with combustion chamber only; "O" unit, without burner and combustion chamber. An electronic safety control proves the flame in boilers burning 7 GPH and up. ASMB constructed. Pro- vision for single or dual domestic water heaters. Load range: Net /=B=R rating. Steam and Water 389,100-793,700 Btu/ hr. No. 72 Boiler for Oil and Oil Heating Unit Exceptional fuel economy due to self regulating, turn-around flue gas travel. Extra large fire box; wide, finned crown sheet. Available as "B" unit, including burner and combustion chamber; "A" unit with combustion chamber only; "O" unit without burner and combustion chamber. ASMB constructed. . Load range: Net rating. Steam 161,000-305,000 Btu/hr.; Water 180,000-331,000 Btu/hr. Type J Gas Boiler for Hot Water or ' Steam Cast iron construction for long life. Large water volume for longer steaming period, less tendency for flashing. Fac tory assembled controls. Completely in- sulated. A.GJL. approved for natural, mixed, manufactured or LP gases; ASMB constructed. , range: Net / rating. Water and Steam 375,100-3,105,600 Btu/hr. . Type G Gas Boiler Large capacity hot water boiler engi neered into new, low space-saving design --A.G.A. approved for closet ana alcove installation. Sections and base factoryassembled for easy installation. Corro sion-resistant cast iron construction. ASMB constructed. Load range! Net I *** B= R rating. Water 45,000-135,000 Btu/hr. Type H Gas Boiler for Hot Water and Steam , Medium sited unit designed for efficient combustion and thorough heat absorp tion. Built to ASME code. AJQJL ap proved. Burns all gases including LP and LP gas-air mixtures. Safety pilot, convenient observation ports. Fully en closing, insulated jacket. ' Load range: Net I*=8-R rating. Wa ter and Steam 72,000-324,000 Btu/hr. Cast.Iron Baseboards * Provide balanced combination of radiant and convected heat to assure uniform temperatures from floor to ceiling. Two heights--No. 7 and No. 9. Complete line of metal finishing accessories. Also Solray Cabinet Radiators, Raydiant Re-, cessed Radiators, Junior Radiators. Heating Systems Aldrich Company 121 E. Williams St., Wyoming, Illinois 337 Boiler-Burner Units, Hot Water Heaters, Domestic and Commercial Oil Burners. The Aldrich line of vertical firetube steel boiler-burner units are ASME constructed and stamped, SBI rated and listed in rating book of Mechanical Contractors Association. The Series "D" units are available in ten sizes for hot water heating, steam heating and hot water supply--oil or gas fired. Boiler shipped with round jacket, insulation, flue baffles, combustion cham ber and tankless coil (if required) factory installed. Burner, trim and controls packed in carton. The Aldrich Series "C"--Gulf Stream boilers are.available in five sizes from 495 to 1260 sq ft water for hot water heating and hot water supply--oil or gas fired. The packaged units are furnished completely erected, pre wired with equipment installed. Units are compact, efficient and economical in operation. Aldrich ASME boilers furnished as high delivery hot water heaters are ideal for large residences, motels, institu tions, swimming pools, barracks and commercial applications where large quantities of hot water are required. Avail able in two types--direct heating galvanized storage (HSG) and indirect submerged coil (ID) with same ratings and either oil or gas fired. Available in wide range of sizes with outputs from 118 to 950 gph at 100 deg rise. The Model E oil burner (0.5-4.0 gph) is available for.domestic use and Model DX (4.5-10.0 gph) and JU (8.0-19.0 gph) for commercial applications. --- * SERIES "D" BOILER-BURNER SPECIFICATIONS Boiler No. D-1S0 D-lflO D-130 D-3K) D-3S0 EM50 D-5J0 D-fllO D-730 D-890 115000 720 108000 108000 144000 180000 1.35 Hot Water Heater(HSGj Output GPH @ 135 170 16 20 24 252000 300 30 34 297000 468000 560 98 42 52 88 60 2020 486000 648000 810000 6.0 594000 594000 792000 990000 7.3 8 775 950 170 129 71 SERIES "C"--GULF STREAM SPECIFICATIONS . Boiler No. C-I0 c-u C-H C-XO C-25 Net Ratiog SBI Water Sq Ft.................. Net Ratiog SBI Btu/hr............................ Gross Output Btu/hr:................................ Gross Input--Gas--Btu/hr....................... Firing Rate--Oil--gpb............................... Tankless Coil Output--gpm.................... Hot Water Heater (HSG) Output GPH @ 100* Rise (40*-140F)........................ Storage Capacity--Boiler--Gallons.... Heating Surface--Sq Ft............................ Number of Flue Tubes.............................. 495 74000 99000 120000 1.0 3 118 19 16 20 580 87000 115000 132000 1.1 3 135 23 19 20 720 108000 144000 165000 1.35 3 170 29 24 20 995 149000 198000 250000 2.0 4 235 31 32 32 1260 189000 252000 320000 2.5 4 300 39 41 32 Gulf Stream Package  338 System* b*<w*. simi )Am e rican -<>tan d ard KEWANEE BOILER DIVISION -toi FRANKLIN STREET. KEWANEE. ILLINOIS KEWANEE STEEL BOILERS ARE CONSTRUCTED IN STRICT ACCORDANCE WITH ASME CODE. With a history of over 90 successful years, Kewanee Boiler Di vision today provides a complete line of steel fire tube boilers, both high pressure and low pressure, for power and process steam in installations from coast to coast and abroad. Both Scotch type and firebox boilers are manufactured, with a total of 36 sizes of Sackaged boiler-bumei- units for oil, gas and gas-oil combination firing. Your 'rtm"" Man is always available to provide complete literature and specifica tions . .. solve installation problems . . . answer every question. Call him anytime. M-800 SERIES--Compact, efficient, economical to operate. High pressure HM Series in 14 sizes, 65 to 651 hp . . . corru* gated furnace as shown. Low pressure LW Series in 16 sizes, 1,332 to 21,855 MBh . . . wet-back design provides additional primary heating surface. Both available as packaged units. SQUARE-HEAT TYPE "R"--Excellent source of heat for any medium size building, this one-piece, all-welded boiler fires efficiently from front or rear with any fuel. Twelve sizes range from 243 to 1,350 MBh 15 psi steam or 30 psi water up . to 250 F. Available with attractive insulated jacket ana packaged for oil, gas or combination oil-gas. Hasting Systems * Beiie*# steel 339 The Babcock & Wilcox Co. 161 East 42nd Street, New York 17, N. Y. Offices in All Principal Cities Water-tube Boilers for Stationary Power Plants, and Marine Services . .. Superheaters .. . Economizers ...Air Heaters ... Pulverized-Coal Equipment... Chain Grate Stokers ... Oil, Gas, and Multifuel Burners ... Seamless and Welded Tubing and Pipe . .. Refractories . .. Process Equipment. WELDED SCOTTIE JR.--Ideal for small industry, 8 sizes of welded Kewanee Seottie Jr. Boilers range in certified ratings from 18 to 62 hp in the high pressure models ; . . 606 to 3,091 MBh in low pressure. Available as packaged unit with integrated burner for oil, gas or dual fuel firing. ROUND TYPE "R"--A rugged boiler with the capacity to serve today's larger, more extended homes. Its heavy steel plate construction assures many extra years of service. There are four Round "R" sizes from 108 to 243 MBh steam or water. Available with square or round insulated jacket. ' "500" SERIES--For heavy duty beating, power or process requirements of hospitals, schools, industries or apartment buildings, the steel riveted ``500'* Series is available in 15 sizes, 32 to 321 hp, for 125.and .150 lb wp .. . and for hightemperature hot water systems above 250 F. Two-pass tubular,- firebox type. - OW AND GW SERIES--Packaged with oil or gas burner and all controls ... for forced hot water beating of small to medium size homes. Compact design permits installation in any con venient location. Rated to produce 74 to 189 MBh. Also available as a boiler unit only, for oil or gas firing. TYPE "C" SERIES--Compact boiler . . . all-welded ... re quires a minimum of floor space. Produces ample steam for heating large buildings at tow cost. 15 psi steam or 30 psi water up to 250 F in 14 capacities 1,236 to 10,800 MBh. Corrugated crown sheet provides additional heating surface next to the fire. Has large firebox. Steel base. STORAGE WATER--Where large quantities of hot water are used at irregular intervals ... and where exhaust or live steam is available--such as hotels, apartments, schools, hospitals, laundries, industrial buildings, etc. Capacities range from 92 to 2,240 gph. Equipped with supporting saddles. BRANCHES IN PRINCIPAL CITIES... STAFFED BT QUALIFIED HEATING SPECIALISTS B&W INTEGRAL-FURNACE BOILER, TYPE FM Shop-Assembled Steam Generator B&W Type FM Boiler combines the benefits of package steam with cost-saving big-boiler advantages. This compact self-contained unit has been widely ap plied to heating services in hospitals, schools, colleges, and other buildings. It has also gained wide acceptance throughout a broad range of industries--supplying steam for combination services. The Type FM Boiler is particularly suitable for small- and medium-sized plants where excessive fuel consumption and costly maintenance are often serious problems. And, even for some larger steam require ments, multiple-unit Type FM installations have proved more flexible in operation and more economical . than one or more large boilers requiring costly field erection and close operating supervision. A large part of the total FM capacity now in service or on order consists of multiple-unit installations. ^ The Type FM Boiler is fast steaming and features automatic operation with special safety provisions. It quickly responds to load changes and operates at high efficiency over the load range. This versatile unit bums gas and/or oil, separately or in combination, with quick and easy changeover accomplished at the control panel. The Type FM Boiler is available in standard sizes for steam requirements to 40,000 lb per hr and for operating pressures to 235 psi. Many have been in stalled for higher pressures and with a moderate degree of superheat. Details are given in Bulletin G-76-- copies sent on request.  340 Heating Systems CLEAVER-BROOKS COMPANY 498 E. Keefe Avenue, Milwaukee 12, Wisconsin CLEAVER-BROOKS Pack aged Boilers for high- or low- pressure steam, or hot water . . . for heating or processing All Cleaver-Brooks boilers meet the foilowing design standards for improved performance and operating safety. (1) Pour-pass five tube construction. Higher gas velocities extract more heat from name, assure better heat transfer with lower fuel costs. (2) Heating surface of 5 sq ft per hp. (3) Forced draft controls air for combustion and assures proper air-to-fuel ratio for top efficiency, elimi nates expensive chimney. (4) Updraft construction with low furnace keeps hottest combustion gases deep within the boiler for greater safety. 19 size*,- ISO models--oil, 'gas or combination oil-gas firing- Model CB boiler (shown) incorporates control panel and other controls on front for conveni ence; available in sixes 15--S50 hp, 15-250 pel. Model LR (not shown) is avail '' able in sizes 400-600 hp, 15-250 psi. Cleaver*Brooks BOILERS--Steam or hot water, for heating and processing 15 to 600 hp, 15 to 250 psi. Oil, gas and combination oil & gas fired models COMPLETE SELF-CONTAINED STANDARD SIZES Rated Capacity--lb iteui per boar <212 F) tewta oes boar (111 F) SO 40 50 60 70 B0 B0 090 IKS I380~ 1725 2070 2416 2760 US ISO mo 250 300 4310 51 BOO SCO 10500 1 110 jjsoo' 17250 100 >450 20700 CLEAVER-BROOKS BOILER ADVANTAGES Guaranteed 80 percent efficiency-- Minimum 80 percent overall efficiency at 30 to 100 percent of full rating at work ing pressures. Quiet operation--Even at peak load, boilers more than meet the low sound levels required for schools, hospitals and institutions. ` Compact--Maximum steam generating capacity in limited space. Requires little floor space . . . fits easily into low head room. Automatic, safe operation--Controls' centralized and conveniently located. Modem electronic combustion controls are standard equipment. Fast installation--No special founda tions needed; existing concrete floors will suffice. Complete unit approval--Labeled by UndenoriUrs' Laboratories and Canadian Standard Association. Conforms to ASME codes; factory tested before shipment. Nation-wide starting service safe guards your boiler investment. Cleaver- Brooks' technician starts boiler,,adjusts it to optimum efficiency and trains boil Fast, easy maintenance--Front and rear doors are binged or davited for fast - inspection, cleaning and servicing. er operator. Fuel flexibility--Burns' heavy or light Full factory tested including complete oil, gas or combination oil/gas--simple, check of control system on every boiler. quicK changeover. Vour boiler is proved ready for efficient performance on arrival at your plant. . Clean--Oil or gas firing keeps boiler room and plant clean, eliminates the No costly chimney--Combustion gases problem of ash removal. are carried off through a small vent, elim inating high-cost chimneys. Totally enclosed control panel--Con trol panel conveniently located, contains One complete package--A complete burner switch, relays, blower motor unit from a single source--one responsi starter and control switches. Wiring is bility. Ready for operation and service in conformity with the National Electric connections on arrival. Code. Write for free descriptive literature and . specifications. Or consult the CleaverBrooks representative listed in your clas sified telephone book under "BOILERS --MANUFACTURERS & DISTRIBU TORS" Cleaver Brooks' One of the originators and largest pro ducers of packaged boilers. ' I CLEAVER-BROOKS COMPANY 498 E. Keefe Ave., Milwaukee 12, Wisconsin Progress For commercial heating applications: apart* meat buildings, hotels, hospitals, stores, commercial and public buildings. Seven sizes up to 2,010,000 Btu output. Steam or hot wa ter, gas or oil fired or combination oil/gaa fired. MODEL M-15 M-20 M-25 M-30 M-40 M-50 M-60 MONITOR BOILER HORSE POWER CAPACITY LB, Steam/hr GROSS Bta HEATING-" SURFACE *q ft 15 520 500 75 20 690 670 100 25 860 - 835 , , 125 30 1035 1000 150 40 1380 1340 200 50 1725 1670 250 60 2070 2010 300 MODEL P-15 P-20 P-25 P-30 P-40 P-50 P-60 PROGRESS BOILER GROSS Bta EDR Steam GROSS 500,000 2085 EDR Water GROSS 3355 670,000 2790 4460 835,000 3480 5570 1,000,000 . 4170 . 6700 1,340,000 5580 . 8930 1,670,000 6970 11,150 2,010,000 8370 13,400 Ckner^Bmb Monitor fedaorf Bo&r Low-cost dry steam for dairies, laundries, dry cleaners, canneries, food processing and industrial applications. Seven sizes . . . 15-40 hp . . . 150 psi. Available in oil, gas or combi nation oil/gas models with quick fuel change * Cleaver-Brooks Progress and Monitor Boiler Advantages: . A complete package--From one company, one source. Factory-assembled, tested and shipped as a fully self- contained unit--ready for installation, and requiring only service connections.' Four-pass, forced-draft design is an efficient combination to transmit a greater percentage of heat to boiler water. Field starting service--final check and adjustment by authorized service representative after installation, plus operator training--at no extra cost. Quiet-running blower supplies combustion air--eliminates need for expensive chimney. Electronic combustion-safety controls assure safe shut-down. Electric ignition assures smooth, noiseless light-off of main flame.. For complete details write direct or contact your Cleaver-Brooks representative listed under "BOILERS--MANUFACTURERS & DISTRIBUTORS" in your classified phone book.  342 Heating Systems COLUMBIA Boiler Company of Pottstown . Pottstown, Pa. 17 Makers of steel power and heating boilers COLUMBIA'S H.R.T.* OIL OR GAS FIRED BOILER & STEAM GENERATOR ifA-- Boiler*, Steel * Gaa Ud OD 343 COLUMBIA Boiler Company of Pottstown Pottstown, Pa. Makers of steel power and heating boilers STEEL, TUBELESS, OIL-FIRED, WATER TUBE GAS-FIRED AND COAL-FIRED HEATING UNITS ASME CODE CONSTRUCTED Available for pressures of 15 to 250 psi. A complete, automatic power plant wherever steam is used for processing Columbia h.r.t. boilers are fully automatic, compact, complete steam generators. Available in sices ranging -from-2 to 100 horsepower. Designed.for firing .with gas, _ light or heavy oils. A special Columbia unit makes pos sible the inter-changeable use of gas or oil. Overfiring Permitted: Conservative ratings plus large combustion volume permit overfiring. This frequently eliminates the need for additional boiler capacity, al lows for plant expansion. High Steam Output; Columbia's h.r.t. boilers have an unusually large heating surface to produce more steam at higher efficiencies. More heat is converted into steam since it is proportioned to make maximum use of hot gases of combustion for the production of steam. Horizontal Design for longer life: The complete sub mersion of tubes protects them from water line cor rosion. Dry Steam Assured: Large steam space and greater liberation area virtually eliminate waste producing water carryover. Over-All Efficiency: Factory installed, specially de signed combustion chamber provides rapid heating re fractory surfaces for peak combustion efficiency. In sulation, 7 inches thick in the combustion chamber _proper,_and 4_inches_thiek in the gas passage, keeps heat loss at a minimum. Special refractory brick'heats' up to great intensity to complete the combustion of previously unignited fuel particles. This complete com bustion not only increases efficiency but makes for clean combustion. Soot accumulation on heating sur faces is minimized. Boiler tubes require less cleaning. Safety Assured: Two pass updraft design lowers direct loss and reduces possibility of furnace pressure, pulsation or excessive combustion noises. Accessibility and easy Maintenance: Simplified con struction provides easy front and back access to the single bank of tubes. Entire unit can be gotten to for inspection of boiler and chamber by removing the SPECIFICATIONS AND DATA COLUMBIA HUT BOILERS FOR GAS, LIGHT OIL OR DUAL FUEL ' HORIZONTAL RETURN TUBULAR TYPE BOILER SIZE 8 10 15 20 30' 40 60 80 100 Bp Rating................................................. Length O.A..........................................in. 58 Width O.A................................. in. 29 Height O.A......................................... in. 44 Water Heating Surface.............. sq ft 30 Oil Firing Rate.................. gal. per hr 2.00 Gas Input...... ..................... Btu per hr 2$o,oa Approximate Output. .. .Btu per hr 200,OCX 69 33 50 56 400,000 300,000 10 69 33 . 60 72 3.5 490,000 350,000 15 84 39 64 92 5.00 700,000 500,000 20 84 39 64 120 7.00 900,000 700,000 30 40 60 80 100 100 100 102 124 124 45 45 52 58 58 68K 68H 80 96 96 200 290 415 548 10.00 12.00 18.00 , 24.00 30.00 l,4O0,00C 1,700,000 2.600.00C 3,300,00C 4,200,000 1,000,000 1,200,000 1,800,000 2,600,000 3,400,000 * Horizontal return tubular type boiler. ASME CODE CONSTRUCTED SBI RATED A.G.A. APPROVED 2* S Uf. 13 Srr- Available with highly efficient, custom engineered gas or oil burners. Columbia steel boilers, gas or oil fired, have self contained large copper instantaneous tank less coils,,supplying. a.continuous flow .of.year ground domestic hot water. ___ Maximum operating efficiencies assured by the bal anced design of the boiler and burner; by the arrange ment of the baffles which force the hot gases to travel four or five times the full length of the boiler. One piece electric welded construction: Columbia offers a heating unit with full electric welded construc tion of heavy copper bearing steel, to assure lower heat ing cost and longer operating life. Quiet operation: Ample combustion space, the insula tion and heavy steel jacket completely eliminate objectional noise. Dual Firing; Columbia oil heating units may be easily converted for efficient gas firing. Oil and gas burners for Columbia Boilers are designed and manufactured by Columbia to insure maximum perform&nce of boiler-burner units and to provide undivided responsibility. MODEL NO. Lie L-18 L-20 L-22 L-24 L-30 Ratings--Oil Fired Input--Gals per Hr........................................ SBI Net Rating Sq Ft Forced Water.................................... .. Sq Ft Gravity Water.................................... Sq Ft Steam..................................................... Btu per hr Forced Water............................. Btu per hr Gravity Water........................... Btu per hr Steam............................................ 1.00 580 510 320 87,000 77,000 77,000 1.20 720 640 400 108,000 96,000 96,000 1.35 990 880 550 149,000 132,000 132,000 1.75 1260 1120 700 189,000 168,000 168,000 2.25 1620 1440 900 243,000 216,000 216,000 3.00 1980 1760 1100 297,000 264,000 264,000 ^Constructed Water^Tube Only ' Gas Fired Units A.G.A. and SUR Approved for outputs from 72,000 to 172,000 Btu's per hour. Coal Hand Fired Conversion Units available in sires L-18, L-22 and L-30 L-32 4.00 2700 2400 1500 405,000 360,000 360,000 L-40 7.00 3500 7 2200 600,000 530,000 530,000 COLUMBIA BASEBOARD RADIATION Suspended Element--no noise 1 Tension Fastening--no rattling! Low Angle Heat--no drafts! Pre-Punched Holes--fast installation 1  344 Beating Systems Mien. Gas od BRYAN STEAM CORPORATION Chili Pike, Peru, Indiana ' Steam Boilers, Hot Water Boilers and Indirect Water Heaters designed exclusively for. oil or gas firing. 1. Bryan Copper Water Tube Boilers are engineered expressly for oil and gas firing. The Copper water tube construction offers these exclusive advantages: 2. Domestic Heating Boilers The Domestic Heating Boilers are available in 9 sizes, from 75,000 Btu to 600,000 Btu output. Oil and gas burners are installed at the factory as packaged units. Factory wiring is optional. Smaller models available as a completely packaged unit with all hot water circulation equipment installed. (a) High heat conductivity of copper heating surface. (b) Extremely rapid water circulation through the small diameter tubing. (c) Tube arrangement causes products of combustion to be finely divided, reducing "surface film" to minimum (d) Relative corrosion resistance of copper. (e) Flexibility of tubes--able to withstand sudden ex pansion and contraction--preventing "thermal shock" damage. (f) Tubes easily replaced--requiring no expensive and time consuming tube welding or rolling. All Boilers are built in accordance with requirements of the ASME Boiler Code. Gas Fired Heating Boil ers are approved by the American Gas Association {AG.A.) ' 3. Commercial Heating Boilers The Commercial Heating Boilers (400 and 500 Series) are available in 8 sizes from 720,000 Btu to 1,800,000 Btu output, for steam and hot water radiation. These sizes are suitable for most schools, churches, small apartment houses and office buildings. Sizes up to 1,080,000 Btu are available as completely assembled and packaged units. 4. High Pressure Boilers Bryan High Pressure Boilers are available in sizes up to 50 hp and up to 125 lb mwp. They are particularly noted for their ability to provide steam for applica tions requiring steam on short notice and at high effi ciency. Hospitals, dry cleaning plants, laundries, dairies, tire repair shops, food processere and many others find them fine for this purpose. 5. Indirect Water Heaters The Bryan Indirect Water Heaters are available in sizes from 112,000 Btu to 1,800,000 Btu output. This heater combines all ef the advantages of the Bryan Copper Tube Boiler with the known advantages of hfating water by indirect means. Widely used for one or two temperature, water in restaurants, soda foun tains, hotels, apartments, laundries, industry and others. Also available as a swimming pool heater. I Heating Systems BoOm, steel CYCLOTHERM DIVISION NATIONAL-U. S. RADIATOR CORP. Oswego, N. Y. 345 CYCLOTHERM STEAM AND HOT WATER GENERATORS Guaranteed Minimum 80 Percent Efficiency. With Cyclonic Combustion, a patented Cyclotherm combustion principle, 65 percent heat transfer is reached in the combustion chamber alone and 15 percent more in one pass of return tubes. 80 percent efficiency--or better--in two passes. Compact. By eliminating superfluous tubes and passes, Cyclotherm produces steam in minimum dimensions. Up to one-third smaller than other pm-fragg boilers. Low Maintenance Costa. Cyclotherm parts are easy to get at, easy to clean. Simplified construction eliminates many man-hours of maintenance. Shipped Complete. A complete package, Cyclotherm is ready to operate when shipped One manufacturing responsibility behind.the entire job. Automatic Controls. On models up to 60 hp, burner automatically shuts off when steam demand is satisfied, automatically turns on when more * m jg needed. On larger models, electronic controls modulate firing rate so that equipment may be operated at from 30 percent to 100 percent of capacity without loss of efficiency. No special foundation or excavation is needed. You can relocate your Cyclotherm if you change your plant layout . No Costly Stack. Cyclotherm requires only a simple flue. . Quick Changeover. Burning oil and/or gas, Cyclotherm offers an easy and quick changeover. You bum whichever fuel is more economical. , Full power from a cold start is reached in 15 to 20 minutes. -Conforms to Codes. Cyclotherm conforms to ASMS codes and carries Underwriters' Laboratories label. , STANDARD BURNER ARRANGEMENTS Light Oil, Noe. 1,2,3, er Dicsd C-600 through C-26,000 18-44 A PI Gravity Hrav^ Oil, No*. 4, s, . 14-20 C-M00 through C-28J3Q0 Gas, mf*., mixed end natural C~WQthrough C-2600 Comb- light oil aad at C-SOO through C-18,000 Comb, heavy oil and pa C-2,800 through C-28^00 Package Hot Water Generators Cydntberm Medela UguOaffg. 1, |.a,or Diced CW-7 through CW-T0 Heavy OU. Nob. ' ' API Gravity Caa, mf, mixed and natural Comb., light ml and pi Comb, heavy oil aadpt CW-7 through CW-70 CW-7 through CW-70 CW-29 throufb CW-70 SPECIAL CONDITIONS SpecaficstioiM are descriptive and not a representation. Equipment described or the equivalent bunated for 0,1 hot water. Cydotberm Division Na- ttonal-U.S. Radiator Carp., ramivee the right to alter, without ootice, dimensions, Cycletherm units. and components of compete information on bow Cycletbena fives yon more steam to less space at tees cost write to Cyetetberm Dtrisien. NatmoaLU. 9. Cws. X- for free booklet. Cyeiotterm Cyclonic Worldwide Service Facilities. Cyclotherm fluids Engineers are ready to serve you wherever you are located. One Year.Warranty. If there is any defect in materials or workmanship within one year of the date of adjustment, Cyclotherm will repair or replace the defective part without any cost to you. r Model No. C-600 C-700 C-tOOO C-1400 C-1725 C-2100 C-2800 C4500 C-4400 C-4200 C-7000 C-8700 C-10500 C-L2QQQ C-13800 C-17500 c-jiooo c-tsooo CYCLOTHERM STEAM GENERATORS Bto Per hr Steam Per hi Lbs Radiation Sq Ft Height Overall lltmffltmn. Width Width Light Oil Heavy Oil Length 602.900 670.000 1.005.000 1.340.000 1.676.000 3.010.000 3.660.000 3.360.000 4.IS7.600 6.026.000 6.700.000 6.376.000 10,060,000 U,TO,000 13.400.000 16.760.000 30.100.000 25.136.000 H !fin u n iig iig iiiliiiiliiiiiiiii 3'6M' 4MH' 4'1H* 4'6* 6' H* S' H* Hi? 6'JH' 7'IM' 7 8M* 7'IW vtw 8'6H* rsa* rw 9' w lO^K' 3'2W JV J'9' 4'tr 4*r 4'3* 4'8* 5'6' i'W 6'6' 7't* 7'1' . ?'#* vsr T9* TIO* 7'10# r bT 6'1' 6'10* Tt* 8'i' 8'1* 8'6' 8'6* 8'6' 8'10* vvr vn* S'O* e'er 1'8* 'll' 91* W9' irr 13`S* WM* I6'9Mr 19'9w 20'lljd' 21'tr 21v >1 'V 22'\\V i# Model No. CW-7 CW-10 CW-14 CW-17 CYCLOTHERM HOT WATER GENERATORS Output Btu per Hr Height Overall DimvMlnM Width Width Light Oil Heavy Oil 1.006.000 63H' 1.340.000 68M' . 1,676,000 1.010,000 ' 68H* 43' 2.680,000 . 70)4' . 62* 3.360.000 70)4' . 62* 4,187,600 5.025.000 sm* 67' 6,700,000 57W* n* M' Length 183)4* - IOTHERM* DIVISION NATIONAL-U. S. RADIATOR CORP., 47 East First Street, Oswego, N. Y.  346 Heating Systems * BMn gm * oa BOILER COMPANY Midland Park, New Jersey The Federal Line of Hydronic Heating Equipment is fully rated in accordance with provisions as set up by the Steel Boiler Institute (S.BJ.) Rating Code. Federal com mercial steel boilers are constructed in conformance with rigid standards as set up by the American Society of Mechanical Engineers. Every boiler receives extensive testing after assembly. Each boiler also bears the ASHE stamp of approval. Other items in the Federal Line, not illustrated here, are: Vertical steam and hot water steel residential boilers; oil and gas-fired cast iron boilers; packaged steel and castiron boilers; `TBC Ultrapower" baseboard radiation; and a full selection of heatiag accessories. 4..................SERIES FD--HORIZONTAL FIRE-TUBE RESI DENTIAL STEEL BOILERS: Available in Stoker, Gas or Oil-Fired Models. 9 full range sizes to meet most residential heating needs . . . from 540 MBh Gross Output to 1800 MBh Gross Output (Net SBl Rating1690 eq ft steam to 5620 sq ft steam). Features newly designed Sue doors to prevent beat loss and infiltration of excess air. Rigid one piece steel base supplied . . . extra Ugh bases for stoker fired models. ASME Coded and Stamped. Provides un limited year round supply of domestic hot water. .4..................SERIES FLR--INDUSTRIAL, INSTITUTIONAL _________ AND COMMERCIAL HORIZONTAL FIRE-TUBE ' ' 'BOILERS!----------- ------------------------------------------------------ 18 sizes for all ranges of heating needs . .. 792 MBh to 12,600 . ` MBh Gross Output (Net SBI Rating--2490 sq ft steam to 39,370 sq ft steam). Features hi-fire box design in larger sizes to increase efficiency of boiler. Dry base supplied in conven tional heights or extra Ugh for stoker fired models. Available with oversized tan Ham coils for abundant year-round domestic hot water supply. SERIES FLW--LOW WATER LINE BOILERS: For industrial, institutional, or commercial applications. Oil or gas-fired. Provides lowest water line of all Federal commer cial firebox boilers. New special wet leg construction completely surrounds combustion area with water walls. Reduces coetly pitting and combustion chamber installations. Supplied with revolutionary windbox to provide controlled firing of modern fuels. 21 full range sizes from 540 MBh to 12,600 MBh Gross Output (Net SBI Rating--1690 sq ft steam to 39,370 sq ft steam). Designed for installation in limited head room areas ... or where water, rock conditions require costly foundation installation. SERIES FM--SCOTCH MARINE BOILERS: For industrial, institutional, and commercial applications. Features "wet back" design for more efficient heat transfer. Compact and nigged, FM boilers are designed for low head room installation. Available in 14 full range sires from 936 MBh to 7200 MBh Gross Output (Net SBI Rating--2930 sq ft , .steam to 22,510 sq ft steam). Oversize tankless coils available for year-round domestic hot water supply. Available in oil or . gas-fired models, jacketed or unjacketed. . Heating Systems > B*un, swi *347 FITZGIBBONS BOILER COMPANY, INC. New York Sales and Executive Offices 101 Park Avenue, New York 17, N. Y. Field Sales Office and Plant, Oswego, New York PRODUCTS--STEEL HEATING BOILERS AND BOILER UNITS for all fuels and all heating systems. Capacities to meet requirements of any building. Built and rated according to ASME and SBI Codes and "Hartford" inspected. 4000 SERIES RESIDENTIAL BOILERS Four sizes - ' 108.000 to 243,000 Btu/hr oil fired Four sizes 99.000 to 195,000 Btu/hr gas fired "PB" PACKAGED BOILER 1975 MBtu/hr to 3113 .MBtu/hr Oil only 7700 SERIES RESIDENTIAL BOILERS Four sizes--oil fired 99.000 to 198,000 Btu/hr 77G1 and G2 . Two sizes gas fired 72.000 and 93,000 Btu/hr "P" PACKAGED BOILER 4 sizes 1975 MBtu/hr to 3113 MBtu/hr Light oil--oil/gas--gas "R-Z-U" JUNIOR BOILER 11 sires . 297 to 1350 MBfcu/hr Steam or water Gas, oil or coal fired "RW" HIGH PRESSURE BOILER For high pressure forced hot water systems lG80MBtu/hr to 15,430 MBtu/hr Gas or oil fired "SCOTCH" TYPE BOILER 16 sizes . 1392 MBtu/hr to 15,430 MBtu/hr Steam or water Gas or oil fired "SCOTCH" TYPE BOILER Available also for burner attach ment at installation or Fitzgibbons factory "R" TYPE PACKAGED BOILER UmTMBtu/hr to 15,530. MBtu/hr Gas or oil fired "D" TYPE BOILER O^MBtu/hr to 15,430 MBtu/hr Steam or hot water Gas, oil or coal fired . Also available in low-set model for special installations Descriptive catalogs on all these Fitzgibbons boilers are available upon request  348 Heating Systems bao, c NORTHVALE, NEW JERSEY PACKAGED AUTOMATIC GAS HEATING PLANTS Providing Space or Volume Water Heating for Residential, Commercial and Industrial Uses 45,000 BTU/hi to 3,600,000 BTU/hr input ratings Model R-1S0 with Hammeroid finish jacket; 425 lbs, 16 in. x 31 in. x 27 in. MUWTemp Multi-Temp Model R-900; 1800 lbs, 65 in. x 26 in. x 37 in. HYRDOTHERM boilers are of all cast iron construction and are exclusively designed for gas. The patented absorption unit, composed of deep-rib horizontal sections connected in zigzag, permits mnrimum heat transfer in minimum space with small water content. This "true" gas design results in low fuel con sumption, quick heat response, uniform heat transfer, self cleaning flue passages, and installation space. HYDRO THERM boilers are A .GA .-approved for ail gases and are factory assembled and wired with safety and gas controls, ready for quick installation. Boiler and controls are enclosed in an attractively finishinsulated steel jacket. - All boilers are tested at 250 lb hydrostatic pressure and carry a 100 lb ASME rating which permits direct connection of boilers to city water lines as required for volume water heating applications. .. MULTI-TEMP, a new concept in heavy duty gas-fired hot water heating, provides any desired capacity with a multiple of HYDROTHERM units, each equipped with its own controls. True input modulation is accomplished by making boiler units respond to the return water temperature through aquastats with differential settings in the return manifold. At a cold start, all units go on; as the return water temperature rises, one or more units drop out according to their own aquastat settings till the input is just enough to maintain the design water tem perature, effecting a year-round fuel saving of up to 20 percent. MULTI-TEMP, being composed of multiple units, offers extra protection against service interruption. Each boiler unit is shipped completely assembled to simplify field installation. CAPACITY BANGS OF HYDSOTHEBMS Space HtitiBf A.GA. Bating* Vain* Water Heattaf GaOaoa per Hoar Car Temperature Biae Shewn Model No. Natural, Mixed and Mintifarlqred Gas input output Bto/hr Btu/br L. P. Cm (Propane) Natural, Mixed and ' Manufactured Gas L. P- Gu (Propane) iSS? Btu/hr Btn hr 1-B-R 60* 60* 100* 120* 140* 60* so* too* 120* 1W OTHEX FAMOUS mrosotMoua reooucu 33.6 168 73 64 43 38 so 67 60 40 33 38 i 67.6 288 115 69 340 136 103 81 58 400 160 130 440 193 144 176 116 680 340 180 144 103 333 730 389 315 134 X 168 840 337 356 169 145 1,000 400 300 R-J00 zoo . 140 1.300 333 1,160 480 380 388 306 464 a ?a5 Ex" DS* i R-800 900 730 400 464 3,600 870 696 1,440 680 430 350 290 360 580 430 >50 390 350 1.680 680 610 410 340 390 670 610 3.000 800 too 400 340 3.330 1310 900 520 1300 620 3.480 1450 1080 870 730 630 1400 1050 Hydra^hiaer - 3$ E-3800 3.600 3.330 ' 14,400 3.480 3.088 3.653 3.784 4.000 1610 1310 960 800 690 1610 1200 960 800 690 4.640 1930 1450 1160 960 830 -I860 800 5,800 3410 1810 1450 1310 1030 3330 1750 1400 6.960 3890 3170 1740 1450 1340 SOT) 2100 1680 1400 s.m 3370 3630 3030 1690 t450 3260 2450 9.380 3860 3890 3310 1930 1650 3730 3800 3340 I860 10.440 4340 3350 3800 2170 I860 4190 3140 11.600 4830 3610 3410 3070 4660 13.760 6300 S98Q 3180 3650 3X70 im 3300 13,930 6780 4340 3470 3890 3480 * Tbern ratals are on piping and pieleap (actor* established by `Tie InHituti ej Bvdtr Moxidacturtr*." When pipint loss are oe*- ligibia, output may be increased 12 per cent, u in panel and baeebaard heatinc, etc. Heating System* BtOm, su*d 349 the INTERNATIONAL BOILER WORKS CO. a 500 Birch Stre<* East Stroudsburg, Pa. A Complete Line of WATER.TUBE Heating and Power Boilers International water tube design assures high h^nt ab sorption and exceptionally low operating cost with all fuels Boiler water circulation is positive and directed, delivering a constant payload of steam or hot water to the boiler nozzle Every International Boiler is built to ASMS code require- menta, and is tested and approved by a nationally recognized insurance company before shipment. Full access is provided for cleaning BOTH the fireside and waterside of all tubes without dismantling the boiler. PACKAGE BOILERS .. .fully automatic and.factory coordinated, the COMPAK * Forced Draft Series Forced draft operation eliminates the need for an induced draft fan or separate controls. Available as Type FPL for low pressure steam or hot water heating and as Type FPH for high pressure steam generation in sizes from 12 to 750 hD. Write for Bulletin 1400. the COMPAK Induced Draft Series . . . noted for high thermal efficiency, quiet operation and k convertibility to coal firing. Type PL'units (15 lb steam, 30^ lb water) . . . and Type PH units (130,160 or 200 psig) are built r tn in sizes from 12 to 600 bp. Write for Bulletin 600. the COAL-PAK AUTOMATIC Bituminous Coal Fired First FULLY AUTOMATIC package unit complete' with combustion controls, automatic coal feed and ash removal system for burning LOW COST BITUMINOUS COAL eleanJv and efficiently. Type PSL (15 lbs. steam, 30-160 lb water) and T/Pe PSH (130, 160 or 200 psig) in sizes from 71.6 to 300 hp. Write for Bulletin 1100, K the THERMOJET-Oil/Gas Fired This LOW HEADROOM-forced recirculation package unit features famous LaMONT boiler design specifically adaoted for SINGLE BUILDING low or high temperature hot water heating systems. Type TJW for operating pressures from 30 to 600 psig in standard sizes from 250,000 to 14,000000 Btu/hr Write for Bulletin 1000. ' HEATING BOILERS--IS lb Steam--30 lb Water TYPE C--built in SBI rated sizes from 2,190 to 51,000 sq ft steam. Can be equipped with an immersion coil of in stantaneous or storage tank type for hot water service require ments. Write for Bulletin tOO. TYPE IDL & BBL Boiler-Burner Units are built in capacities from 1,820 to 84,000 aq ft steam. Write for Bulletin* 600 and 900. INTERNATIONAE-LAMONT .... HIGH PRESSURE BOILERS--130--160--200 psig .TYPE CH Of all welded construction these boilers are available in standard sizes from 8 to 363 hp-oii, gas or coal fired. Wnte for Bulletin 1600. . TYPE 1DH & BBH Boiler-Burner Units, including water tube boiler, steel base and induced draft fan, are shipped as a unit ready for installation of oil and/or gas burner and controls at job site. Built in standard sizes ranging from 12 to 600 hp. Wnte for Bulletin* 400 and 900. K HIGH TEMPERATURE WATER GENERATORS ___ Discharge Temperatures to 430 F. Design Pressures to 600 psig 1 . U1HLT-IN ECONOMIZER permits safe use of tempera ture differentials to 200 F with no thermal Bhoek. LOW HEAD ROOM reduces cost of new boiler house construction and permits installation in many existing structures. TYPE LFW available in standard sizes from 3 to 200 million Btu/hr Completely packaged oil/gas fired units to 60 million Btu/hr Wnte for Bulletin 700. THERMAL LIQUID HEATERS Safe, low pressure industrial process heat to 750 F us temperature control to 2 F. Ideal for use with Arocior* I owtherm, Mobiltherm and other thermal liquids. 'I . EA available in standard sizes from * 150,000 to 50 million Btu/hr. Completely packaged units in sizes to 20 million Btu/hr. Write for Bulletin 1300. See Vow Local INTERNATIONAL DISTRICT REPRESENTATIVE or write for Bulletins above  350 Heating Systems &, smc> Johnston Brothers, Inc. Established 1864 Ferrysburg, Michigan Member PACKAGED BOILER UNITS FULLY AUTOMATIC OIL OR GAS OR COMBINATION OIL AND GAS FORCED DRAFT THREE PASS AND TWO PASS COMPLETELY ASSEMBLED AND FIRE TESTED AT FACTORY HIGH PRESSURE TYPE from 75 to 750 hp and pressures of 125, 150 and 200 lb psi (250 lb available as a special). LOW PRESSURE TYPE for beating; 15 lb pressure, and EDR rating from 2190 sq ft to 42,500 aq ft steam. ASME Code construction. Underwriters' Laboratory and Factory Mutual Approved. Specification Forms in detail to exactly cover the requirements of any particular job will be furnished upon request and without any obligation what ever. Ask for Bulletins 509-B, 9600. POWER, PROCESS, HEATING 15 to 400 hp and pressures 15 lb to 200 lb psi. For mechanical firing with Coal, Gas or Oil. Overloads up to 200 percent of rating readily developed. Oil or Gas firing equipment and controls can be in stalled for completely automatic opera tion and in emergency or fuel scarcity, can be readily converted to Coal firing. Ask for Bulletin 1000 and 9500 Firebox Heating Boiler, Compact Type. Oil, Gas, Stoker o* Hand Firing. ThreePass, 15 lb pressure, ASME Code. Ca pacities 2190 to 42,500 sq ft, SB1 rat ing. Ask for Bulletin 1500. Also built for High Pressure (125 psi). Ask for Bulletin 7Of. WATERBACK DESIGN--Special attention is directed to this valuable feature. The rear combustion chamber is entirely sub merged within the boiler water, eliminating use of firebrick,'tile, or rear end refractories, thus avoiding the necessity of frequent repair and replacement costs. SERVICE--Located in each sales area is a factory trained Service Engineer, capable of checking all phases of operation-adjusting controls and equipment to insure continuous maximum performance. Johnston service is prompt, liberal and cooperative--it a available to all customers. . 351 ORR & SEMBOWER, INC. Builders of Dependable Boilers Since 1885 Reading, Pa. World-wide Factory-trained Sales and Service Representatives and POIVERPAK Packaged Automatic Boilers Fuel Burning Systems--oil, gas and combination oil/gas . Powermaster boilers are modem, completely factory-assem bled, automatic units with a world-wide reputation for highly dependable and efficient performance in public buildings, hospitals, schools, apartments, industrial plants and other installations. Three standard models are available in sites of 20 hp to 600 hp for steam generation to 250 psi, and for hot water to 30 psi. All models are designed and built to ASME Boiler Code requirements, apprQved by Underwriters' Labora tories, Inc., and fully guaranteed by Orr 4 Sembower, Inc. All units are factory fire-tested and afford these advantages: Simple cost-saving installation .. High efficiency at all loads Instant response to load swings . 3-pass boiler with 5 sq ft of heating surface per bhp Forced draft firing Quick fuel change-over . Clean, quiet operation Fully automatic operating and safety controls Convenient accessibility for inspection and servicing Nation-wide factory-trained service Powermaster Hot Water Boiler--Powermaster is one of the first hot water heating boilers developed and constructedspecifically tor modem institutional, commercial and indus trial forced circulation heating applications. The Powermaster hot water boiler design and construction utilizes a dip-tube outlet located at the top of the boiler shell, designed to eliminate entry of air and vapor. The return con nection, located at the center on the top of the boiler, is baffled to direct return water from the system down around the ' outer surface of the boiler. An integral vent connection is' provided on the boiler. The 04 S Powermaster hot water boiler is not simply a steam boiler converted to hot water service. Its provisions for insur. ing efficient and effective internal circulation are the result of two years of concentrated research and development. These four advantages of the Powermaster packaged automatic hot water boiler emphasize its importance for every forced circulation hot water system: 1. Powermaster hot water boiler offers more protection against thermal shock. 2. Powermaster internal circulation path eliminates short circuiting. 3. Powermaster internal circulation system eliminates stratification. . 4. The hot water Powermaster insures uniform tempera ture gradients throughout the boiler. Write for information on the Powermaster packaged auto matic boiler to meet your specific needs.  352 Heating Systems w, c Raypak Company, Inc. 2416 Chico Avenue, El Monte, California THE ADVANCED LINE OF GAS FIRED 100% COPPER AND BRONZE WATER TUBE HOT WATER BOILERS. 20 YEAR GUARANTEE ON CENTRAL HEATING SYSTEMS. 160-T thru 1200-T ex tended jacket standard. Models -- TP typical pre-assembled package for central heating. Raypak-boiler cutaway with HWTG controls and Unatherm Gover nor.! pat. pending) X MODELS cover standard boilers for central fluid heatiagy volume hot water supply and sanitising 180F hot water applica tions. They feature a readily cleanable heat exchanger with indi vidual bronze plugs for each tube, extended jacket, and gas modulation governed by water temperature. Temperature ranges to 240F. XP MODELS cover the "plug-in" central heating package which Raypak developed and for Which Raypak is so well known. They feature, in addition to T Model specifications, a high head circulator, heavy duty expansion Lank with air charger, air vent, automatic make-up facilities, indicator gage, relief valve, trans former relay (where applicable)--all wired and piped. The 80-TP Special, not a plug-in package, is an 80-T with pump, tank and accessories shipped loose. . HWXG.MODELS include fully automatic swimming pool heaters. They feature Raypak's Unatbenn Governor which prevents damaging condensate and virtuallyeliminates scaling--automatically --by maintaining 1(6-110F. boiler outlet temperatures regardless of flow rate changes from the filter system. In addition they feature a built-in pool aquastat, a self-contained independent electrical sys tem and a low water cut-off device; no outside wiring--indefinite beat exchanger life, permitting no cost do-it-yourself scale removal' All models feature eitendedand integral copper fin tubes, tapered bronze distribution headers, large 10 interconnecting bronze header in the combustion chamber, monolithic cast lightweight refractory, heavy 18 gage stressed-sktn jacket, light weight (3 times the BTlTs per pound of weight), compactness, A.G-A. approval on combustible flooring, and noiseless stainless steel ported burners with drawer-type mounting pan. RAYPAK XRI-XEMP SYSTEM (patents pending) is a package for the food serving industry providing three tempera tures of water from one boiler and includes glass-lined storage tank and beater coil. 80-T and 120-T with flush jacket. -NOXES- NEW! Interconnecting bronze manifold design prevents air cavitation in heat-exchanger. NEW! Heat exchanger jacket panel permits boiler water tubes to be inspected and cleaned without breaking pipe connection*. Raypak stainless steef burners permit the same propane ratings as for natural gas on every size boiler. ' 160 lb. working pressure on ail models. Standard beat exchangers tested at 1000 psi Hydrostatic pressure on request. Model 80-T 120-T 160-T 225-T 310-T 400-T 600-T 800-T . 1200-T MBH Input 80 120 160 225 310 400 600 800 1200 MBH Output 64 96 128 180 248 320 480 640 960 EDRSq. Ft. Gross 425 642 853 1200 1600 2133 3200 4270 6400 Approx. Wt. # 150 165 220 250 325 400 500 700 1000 Heating Systems etier, steel 353 TITUSVILLE IRON WORKS DIVISION OF STRUTHERS WELLS CORPORATION Titusville, Pennsylvania TITUSVILLE TYPE WTP PACKAGED STEAM GENERATOR This compact, shop-assembled water-tube steam generator features simplicity and economy of operation, from 10,000 to 60,000 Its of steam per hour. It is shipped as a package complete with firing equipment, controls and all other components installed ready for service connections m the field. Enclosed and protected by ail-welded, pressure-tight steel casing, the unit is easy to move by lifting or skidding, and erection costs are reduced to a very low minimum. Forced draft, pressurised furnace operation eliminates need (or stack or induced draft fan. The Titusville WTP Steam Generator ** ',"c''~ned to use heavy oil, heavy oil and gas combination; light oil; light oil and gas^mbination; natural gas; manufactured gas; coke oven gas. Fully^autoniatic weldin"g ` employed, welds ate X-rayed, and drums stress-relieved. Bulletin B-&65. TITUSVILLE 3-PASS Scotch Marine Boilers The Titusville 3-Pass Scotch Marine Boilers for power (S-3P) and heat (S-3H) are compact to the limits of practical size while rrmmiftining excellent thermal qualities. Featuring complete wet4ck construction, eliminating refractory problems, these modern boilers have water-cooled rear combustion chamber, large primary heating surface area, 3-pass tubes for maximum efficiency in heat extraction. Heat release rates of less than 88,000 BTG/cu ft of furnace volume at maximum continuous output ratings assure easy firing by ail leading types.of forced draft packaged burners. Pleasing appearance joins with practical design for ample acces to all sections of boiler for inspection and maintenance. ASME power and heating boiler codes followed through out in design and construction. Bulletin B-33S3. TITUSVILLE TICOTHERM STEAM GENERATORS These large, highly efficient water tube steam generators are economical in opera tion and compact in design. They are constructed to meet or exceed a safety factor of 5, and drums are fusion welded, X-ray tested and stress relieved to meet or exceed ASME requirements as well as all local and state codes. Excellent results are achieved with any type of fuel. Ticothenn Steam Generators are completely insulated--top, rides and reax--with s minimum of 7 inches of refractory and insulation at side walls; boilera are completely steel encased. Four passes of gas travel are provided by vertical baffling, resulting in a Tnm.Trwim of draft loss and maximum heat absorption. Soot blowers are furnished as standard equipment on all boilera except gas-fired models. Bulletin BS260-A. TITUSVILLE ALL-WELDED FIREBOX BOILERS High and Low Pressures Hie Titusville Compact Steel Heating Boiler (right) is compact in design, requiring . less boiler room floor space than any other type. Excellent operating economies are obtainable, due to the unit's modem 3-para construction feature. Built for use with all fuels and all types of firing--ample c--o--m---b--u--s--t-i-o--n--s- *p---acee iiss pprroovviiddeedd ttoo eeccoonnoommiiccaallllyy bbuumm oil, gas, or coal. These all-steel boilers arc manufactured in 19 different <nyes rated in accordance with latest rating code of The Steel Boiler Institute, constructed ASME code rules. Bulletin No. BS000-B. Type WP Titusville All-Welded Firebox Boiler (left) is all-welded, utilising ad vanced welding methods, quality steels and modem fabricating techniques. A streamlined boiler of exceptional strength, it has no riveted seams or screwed stays, remains tight under all operating condi tions. Self-cleaning crown sheet and ample clean-out facilities are included in the design. These boilers combine high efficiency and low maintenance in service, and are readily adaptable for burning all rises of bituminous and anthracite coal, or, in the WPO Model, for using any recognised oil, gas or combination gas oil burners. Bulletin No. B-90S0. Write Jor the descriptive bulletins in which you are interested--let us arrange to have our nearest representative call to consult on your heating or power boiler re quirements--without obligation oj any kind.  354 Heating Systems stem cewn-mn VAPOR HEATING CORPORATION 80 East Jackson Boulevard * Chicago 4, Illinois New York St. Paul Denver Washington Philadelphia Atlanta San Francisco Houston Richmond Los Angeles M. Louis VAPOR MODULATIC WATER-TUBE BOILERS Healing System* WESTERN BOILER COMPANY 1600 North Indiana Street, Los Angeles 63, California 1 Vanderbilt Avenue, New York 17, New York 355 Detailed on this page are a few of the many features of Webco-Ray packaged heating, power and process steam boilers. Webco-Ray 3-pass boilers combine in a single guaranteed package, the skills and experience of two leaders in heating and power equipment. All units are assembled, pre-wired and test fired at Western Boiler Company prior to shipment, making possible immediate hookup at the job site. Component parts are integrated for balanced, eco nomical performance and dependability. Forced Draft design eliminates unsightly, coetly, tall stacks, an im portant advantage in todays modem buildings. Sizes from 10 to 600 boiler horsepower, 335,000 to 20,085,000 Btu/hr for oil, gas and combination oil-gas operation. DRUM TYPE Dependable, compact. Vapor Drum Modulatics are de signed to turoish high or low-pressure steam, with high or low temperature hot water for heating, power, proc essing, countless production applications, y* the size and weight of conventional boilers of comparable ratmgs^MriduIatics provide 4 bhp per sq-ft of.floor.space.. . Largest size takes only 40 sq ft, fits easily in unused corners or aisles. Lowest installation cost--Modulatics are delivered as complete units factory assembled, wired and job-tested, ready to connect and fire up. Largest unit fits through plant doors. No special foundations or chimneys required. . Operation is fast, positive, automatic. Full steam m 5 minutes, or instant hot water, from cold start. Tracks fluctuating steam demand up or down with speed and accuracy. . .. . Multiple-unit Modulatic installations can have a sin gle,. automatic coordinated control that cuts whole units in or out as steam requirements vary, and modu lates between these steps. Several smaller units always operating at design capacity minimize the inherent in efficiency of idling, larger boilers as steam demand slackens. Modulatic boilers , never require replacement because design permits easy, simple replacement of water-tube coils, or other parts, for lifetime peak efficiency. Built-in automatic safeguards against no water, flame failure, excessive pressure. All Modulatics conform to ASME Power-Boiler Code and ASME Heating-Boiler Code. DRUM.TYPE SPECIFICATIONS IN BRIEF Si* Sires ........................................................... Presuits ............................. ................. Fuel ........................ Floor Area (tOO bp) Height (WO bp)......... Floor Load (max.) . Operation ............... .JO to 100 hp .. .0 to IS pti 5 to ISO Oil Gas, or Combination 6 ft x Sit ........................T ft * in. .......,...............150 lb/aq ft ___ .Automatic INDUSTRIAL TYPE Heavy-duty Modulatic boilers are made in nine sizes to 150 bhp and pressures to 1000 psi. These industrial boilers have all Modulatic advantages of compactness, quick steaming, flexibility, and high operating efficiency with reliable, automatic performance and minimum maintenance. Thousands of Modulatics have proved themselves in tough, demanding service throughout the world. Literature is available upon request Iot both drum type and industrial type Modulatics. INDUSTRIAL-TYPE SPECIFICATIONS IN BRIEF Eigbt Sixes ............... Pleasures ....... ........ Putl ............ ....... Floor Ares (IM hp) Height (ISO hp) ... Floor Load (max) . Operation ................. 1000.......................... 10 to ISO hp ..................... S to pti Oil Gas. or Combination . S ft x 8 ft .............................. 0 fl. 10 ia- ............................. ISO lb/aq ft .............................. Automatic PACKAGED PRESSURE FORCED DRAFT: These raggedly constructed Webco-Ray packaged boilers are ideally suited for fully.automatic forced draft operation in the 10 to 100 boiler bp, 335,000 to 3,348,000 Btu/hr range. Units, are avail able for light oil, natural gas or combination gas-oil operation. All are guaranteed to provide quiet, efficient and economical performance. With Webco-Ray Pressure Forced Draft units, a single motor provides complete power for both the fan and oil pump with resultant savings in electricity. The single fan furnishes all air necessary for combustion and to overcome draft loss through the boiler. Air is supplied under constant pressure unaffected by atmospheric conditions. These forced draft features eliminate the need for tall stacks or other auxiliary draft equipment. Only a gmail vent is needed to carry off spent gases. Burners meet all requirements of the National Electric Code and Underwriter*' Laboratories. PACKAGED ROTARY FORCED DRAFT: This highly ef ficient Webco-Ray packaged boiler is fully automatic, in corporating the Webco-Ray Forced Draft System. It is designed and built to comply with the requirements of the ASmE Code and displays the appropriate Code symbols. Sized from 40 to 600 boiler hp, 1,339,000 to 20.085,000 Btu/hr, units are available to achieve efficient combustion of light and heavy fuel oils--high or low pressure gas. Combination models fire either oil or gas. Webco-Ray boilers feature large furnace volumes for high radiant heat transfer, quiet operation, longer life and minimum maintenance. -. Forced Draft--The Webco-Ray forced draft system-enables this unit to operate efficiently on all fuels regardless of external atmospheric conditions. Forced draft firing eliminates the need for costly, unsightly tall stacks or overfire draft controls. Only a small vent is required to carry off spent gases. The belt-driven forced draft fan can be easily adjusted to compen sate for varying altitude factors. BOILER OUTPUT Sixe " EDR Steam Sq Ft EDR Water Sq Ft Heat Output Oil Firing X 1000 Rate GPH BtnAr 10 ' 1390 2230 335 2.8 15 2090 3350 502 4.2 . 20 . 2790 4460 669 5.6 25 3480 5570 836 7.0 30 4180 6690 1002 8.4 40 50 60 5580 7000 P- 8400 8920 11200 13400 1339 1674 2009 11.2 14.0 16.8 70 9800 15600 2343 19.5 80 11200 17900 2678 22.3 90 12600 20100 3013 25.1 100 14000 22300 3348 27.9 Gaa Firing Rate CFH 418 628 837 1046 1255 1674 2092 2511 2929 3348 3766 4184 Sixe. 115 125 150 175 200 225 250 300 350 400 500 600 BOILER OUTPUT EDR Steam SqFt EDRWater Sq Ft Heat Output X ION Btn/kr 16000 25600 3845 17500 27900 4184 21000 33500 5021 24500 39100 5858 28000 44600 6695 31400 35000 50200 55800 7525 8369 42000 67000 10043 .49000 78100 11716 56000 89300 13390 70000 111600 16738 84000 133900 20085 Oil Firing Rate Gffi 32.0 34.9 41.8 48.8 55.8 62.7 69.7 83.7 97.6 111.6 139.5 167.4 Gaa Firing Rate era 4810 5230 6276 7323 8369 9400 10461 12553 14645 16737 20922 25106 Capacities based upon Fuel Oil at 150,000 Btu/gal, gas at 1000 Btu/cu ft, and boiler efficiency of 80 percent ARMSTRONG MACHINE WORKS 851 Maple St., Three Rivers, Mich. GUARANTEED: SATISFACTION OR YOUR MONEY BACK Traps Available from Local Stocks of 45 Factory Representatives 135 Jobbers, or Through the Supplier of Your Choice, or Direct from Factory Open Float and Thermostatic Traps for Low Pressure Heating Service ArmstrougO.F. AT. traps answer the specific needs of low-pressure intermit tent service where huge amounts of air accumulate when the steam is off-- especially good for unit heaters, pipe coils and standing radiation. Design is open-float, single valve, with bi-metal controlled air vent. Conven- . tional float and thermostatic connec tions--$4 in. to 2 in. a Mechanisms are of the same design, materials and workmanship as those used in Armstrong forced steel inverted- bucket traps for high-pressure, high- temperature service. Bodies and caps are close-grained cast semi-steel, de signed for pressures to 250 prig. Further information in Bulletin No. 775. FEATURES 1. Low First Cost--on the basis of actual capacity for discharging hot condensate. No. 880 (% in.) has a capac ity of 640 lb/hr at 15 psi, lists at $12. Other capacities to 6800 Ib/hr. 2. Easy Installation--horizontal -straight-through pipe connections mini mize fittings and labor. Also, traps can be equipped with internal check valves. 3. Long Life and Low Maintenance --Armstrong 0- F- A T. traps are non-, air-binding and self-scrubbing. Working parts are corrosion-proof. Open-float is non-collapsible. Inadvertent admission of high pressure stream will not harm trap. Traps hydraulically tested at 500 prig4. Automatic Air Elimination-- ' during warm-up, thermostatic vent is wide open to discharge large amounts of ARMSTRONG INVERTED-BUCKET STEAM TRAPS Side Inlet, . Side Outlet Bottom Inlet, Side Inlet, Top Outlet Bottom Outlet Integral Strainer ` For draining steam mains and all types of institutional and industrial steam-heated equipment--including hot water heaters, and kitchen, hospital and less to buy and install than standard trap plus separate strainer. Following table lists types, connections, and max imum capacities of hot condensate: laundry equipment. High capacity for size due to time-tested two-phase lever age system. Sizes for every capacity need. Oast semi-steel models may be used Type Mt Connections b. (ivfc) for pressures to 250 psi. Forged steel models available for higher pressures. Features: basically the same as those Side Inlet-Side H toi% 7500 outlined above for O. F. A T. traps ex cept for the extra large air-handling capacity--air is discharged through the bucket vent. Choice of body styles and built-in accessories minimise fittings and instal Bottom Inlet-Top Outlet Side Inlet-Bottom Outlet Integral StraiDer H to 2 19000 XorX 570 M to 1)4 3500 lation labor. Each type available with . thermic vent for handling faster heat-up and/or internal check valves. Integral strainer traps are available which cost Other Armstrong traps available with capacities up to 300,000 Ib/hr. Complete details in Catalog K. air rapidly. Regular vent handles normal air and/or CO, in system after heat-up, venting it at steam temperature. 5. Fast Condensate Removal--con- . densate is discharged at steam tempera ture--as fast as it enters trap. No cooling leg needed. 6. No Steam Loss--valve parts are always water sealed, and cannot be nickel by. dirt or scale. Excellent for vacuum service. Y-TYPE STRAINERS Semi-steel: screwed, in-2 in.; flanged, 2 in.-6 in. Carbon steel: screwed or socket weld, yi in.-3 in.; flanged, 2>$ in.-6 in. Chrome moly: screwed or socket weld, J4 in.-2 in. Bronze: screwed or silbras, H in-2 in. Type 316 stainless: screwed or socket - weld, H in--2 in. - ' Y-Type Strainer Air Relief Trap AIR RELIEF TRAPS Ball-float traps for venting air from high points in hot-water systems. Cor rosion-proof stainless-steel mechanisms. Smallest sire is No. 21 (shown above)-- 14 in. or % in. connections, 6J4-in. diameter, capacity of 10 cfm at 30. psi, list price $16.00. No. 21G, same capacity as 21 but fits between studs. Heating Systems . spdu 357 MUELLER STEAM SPECIALTY CO., INC. 29 Meserole Avenue, Brooklyn 22, New York /1 1 \' | MUELLER | 1 I. 9 No. 751 No. 175 . STRAINERS FOR ALL SERVICES 251 SELF CLEANING "Y" TYPE K in- through 3 in. Cast Iron, Cast Steel, Bronze and Aluminum. Pressures up to 600 lb steam. 751 FLANGED SELF CLEANING "Y" TYPE Sizes l`)4 in. through-16 in. Larger 6izes available on application. Available in Cast Iron, Cast Steel, Stain less Steel and Bronze. Pressures up to 600 lb steam. 155 and 165 BASKET TYPE Basket-Type Strainers available with screwed or flanged ends, in CasfSteel, Cast Iron, Stainless Steel and Bronze. Furnished with closed or open bottom baskets. Baskets lined with mesh are available where very fine screening is required. Drain plug at bottom of strainer easily removed for blowdown of accumulated sediment. 145 BASKET TYPE . Sizes \4 in. through 3 in. Iron Body and Bronze Body screwed end removable Basket-Type Strainers. Screens and Baskets made from a variety of per forated metals and wire mesh available for all types of strainers. .' .. No. 155 X Cast Carbon Steel and Stainless Steel Basket Strainers are available for gasoline and jet fueling applications ... In full accordance with U.S. Government Specifications. . Every Mueller Strainer is individually tested and fully guaranteed PRESSURE DROP CHARTS ON MUELLER STRAINERS AND 1959 CATALOG ARE AVAILABLE ON REQUEST. #358 Heating System* McDonnell & miller, inc. 3500 N. Spaulding Ave., Chicago 18, 111. McDonnell Feeder Cut-off Combinations McDonnell Low Water Fuel Cut-offs Better Water * U*d C*oInli McDonnell & miller, inc. 3500 N. Spaulding Ave., Chicago 18, 111. 3Ln^dL /\gyv 359 McDonnell Pump Controllers and Low Water Cut-offs McDonnell Make-up Water Feeders No. 47-2 No. 47*2 ia for steam boilers used in closed heating systems, up to 5000 sq ft capacity. Feeder adds water automatically to boiler as needed, to maintain a safe level at all times. Cut-off switch stops burner if water level drops into emergency tone. Features include cool feed valve, deep sediment chamber, self closing blow-off valve. Quick Hook-up, straight thrust stain less steel valve, packless construction. Maximum steam press ure, 25 lb. Maximum water supply pressure, 150 lb. Shipping wt., 30 lb. No. 47 Boiler Water Feeder. Same as No. 47-2 but without No. 2 Cut-off Switch, for hand-fired boilers. Shipping wt, 291b. No. 51-2 is for steam boilers above 5000 sq ft capacity. Same basic features as No. 47-2 above, but has larger capacity and is installed with 1 in. equalizing pipes. Maximum steam pressure, 35 lb.Maximum water supply pressure, 150 lb. Shipping weight, 39 lb. ....... No. 51 Boiler Water Feeder. Same as No. 51-2 but without No. 2 Cut-off switch, for hand-fired boilers. Shipping weight, 38 lb. . No. 247-2 is for hot water space heating boilers. Hot water boilers can run into low water difficulties as a result of leakage, prolonged discharge by the ASME relief valve, or even failure to fill system properly. The No. 247-2 takes care of such situa tions by adding water as needed, and by stopping the burner should the water level drop into the emergency zone. Same as No. 47-2, but specially adapted for hot water service. Installed with 1 in. equalizing pipes. M-ximum boiler pressure, 30 lb. Maximum water supply pressure, 150 lb. Shipping weight, 241b. No. 247 Boiler Water Feeder. Same as No. 247-2, but without No. 2 Cut-off switch, for hand-fired boilers. Shipping weight, 23 lb. . No. 67 No. 63 No. 67 is for steam boilers of any size; maximum steam pres sure 20 lb. Dependably stops burner when water level falls into danger zone. Has deep sediment chamber, packless con struction, Quick-Hook-up, and extra switch which closes on small drop without stopping burner to operate alarm or control No. 101 Electric Water Feeder. Shipping wt, 11 lb. 69 Series "Built-ins" fit 2H in. tappings provided in most modern jacketed boilers. Individual models in the senes--No. 69 169 269,369,469,569 and others--vary principally in length 67of.'mounting barrel, are specified by boiler make and model numbcrrSame operating mechanism as.No., . Shipping wts. vary from 4H to 9 lb. No. 63 is designed especially for use on hot water space heating boilers Handles boilere of any size, pressures to 50 lb. stops burner and prevents damage to boiler if low water condition occurs (Can also be used on steam boilers.) Installed with 1 in. FS4 Series McDonnell No. 101 Electric Water Feeder Used with No. 67 and "Built-in" cut offs--adds the convenience of automatic water feeding. For boilers to 5000 sq ft. Maximum steam pressure, 25 lb; water supply pressure, 150 lb. Water tappings, K n. Shipping wt, 8 lb. For gas DOileis with low voltage control circuits order No. 101-24V, complete with transformer. Shipping wt, 12 lb. McDonnell FS4 Series Flow Switch Dependable, moderately priced device that makes or breaks electrical circuit when flow of liquid in a pipe starts or stops. Used to turn on signal or alarm, or start a motor, burner or metering device. Parts contacting liquid are copper, brass or phosphor bronze. Seg mented paddle easily adapted for 1 in. or larger pipe. Models available to make or break circuit with flow. Shipping wt,, 3 lb. . No. 150 is for steam boilers of any size. Maximum steam pressure, 150 lb. Most widely known and used control of its type. All operating parts are away from heat. No stuffing box to bind or leak. Has two-switch construction. One starts and stops pump as boiler calls for water; second operates on greater drop of water line to stop burner and/or complete alarm cir cuit. Has 1 in. equalising tappings. Shipping weight, 31 lb. No. 157 is same as the No. 150 above, but with water column type float chamber that greatly simplifies installation on boilers having separate water columns. Has tappings for H in. Water glass cocks, 1 inch equalizing pipes and in. tri-cocks Shipping weight, 50 lb. No. 92 is for boilers of any size. Maximum boiler pressure, 250 - lb. New control on the market. Introduces the principle of repulsion magnetic switching. Remarkable dissipation of heat permits use of 75'C wire in junction box, as now required by Underwriters' Laboratories. Installed with \\i in. equalising pipes. Shipping weight, 64 lb. ' . No. 192 is same as the No. 92 above, but with water column type float chamber that greatly simplifies installation on steam boilers having separate water columns. Body includes tappings for in. gage glass and tricocks, and for 1) in. equalizing pipes. Shipping weight, 69 lb. McDonnell 202 Series Pressure-Temperature Relief Valve Wo> M2092 For hot water tanks and heaters. Bears . the ASME symbol of approval, with pressure relieving capacity Btu rated by Notional Board. Also listed by AG.A. All connections are in. internal tap pings. Features special connection for flow to fixtures for easier hook-up, better oorpdeerratNioFn;miofdueslse. of this is not feasible McDonnell Valve No. With Fittnrt Connection Without Presssre BtuVhr. 202-75 202-100 202NF-7S 202NF-100 202NF-I25 75 100 125 650,000 4 No. 27T No. 21 No. 27T teams up with McDonnell pump controls to pro vide the one good way to control water level in steam - boilers. Pump control calls for water as the boiler itself dic tates. No. 27T makes sure there is always an adequate mini mum supply in the receiving tank. Has large feeding capac ity; stainless steel valve; all brass valve body. For external hook-up with 1 in- equalizing pipes on existing receivers. Feed water tappingB, in. Shipping weight, 39 lb. 21 Series Teams up with McDonnell pump controls. Makes sure there is always an adequate minimum supply in receiver - when pump control on boiler calls for water. Mounts right on receiver, and feeds directly into it. Two standard flange sizes fit most existing tank openings: No. 21 has six bolt boles on 5% in. bolt circle. No. tl 'on 814 in. circle. Feed water tap pings, % in. Shipping weights, 15 and 26 lb. McDonnell 230 and 240 Series Pressure Relief Valves '`Comply' with" ASME Boiler Code-in every respect; tested and Btu rated by National Board of Bailer and Pressure Vessel Inspectors. Basic construction of all valves is the same, except 240 Series has outlet one pipe size larger than inlet. All operating parts of non-corrosive materials. Independent-action testing levers cannot hamper normal operation. No. 230-H in.-30 For Hot Water Space Heating Boilers McDonnell Valve Boiler Sise No. BtuW. Inlet Outlet Opening Pressure ShipWeigft 330-H IN.40 803.000 330-1 IN.-30 ItO-l JN.-S0 910.000 1.029.100 1.500.000 3,313,000 2.710.000s.uo.om 3,950.000 3 3 3 1H 36 29 ^Recommended:IS lb. opcniai valve, with (mailer JtMb. valve for thermal For Hot Water Tanks and Heaters >360 Heating Systems S>tnrffHr Seprt*ry . BtUitiM, Cafe Beeler WILSON ENGINEERING CORPORATION 6 North Michigan Avenue, Dept. HG59, Chicago 2, Illinois WILSON CENTRIFUGAL BLOWDOWN SEPARATOR SOLVES BOILER BLOWDOWN DISPOSAL PROBLEMS Here is the safe, economical way to handle boiler blowdown ... at atmospheric pressure. Steam flash is instantaneously cleared through the large top vent pipe. Water and sludge fall by gravity. through bottom drain. No objectionable noise. Install where con venient, inside or out. One Wilson Separator can handle two or more boilers in battery, if desired. Special' models with flanged or butt welding connections available. MEETS REQUIREMENTS OF A.S.M.E. UNFIRED PRESSURE VESSEL CODE SIMPLE TO INSTALL REQUIRES NO MAINTENANCE THOUSANDS IN SERVICE WILSON ALL-CAST ALUMINUM RADIATION ELEMENTS Wilson All-Cast Aluminum Directional-finned Radiation Elements are readily adapted to many applications. The patented 46 directional fin feature and the chamber shape provide for com pact installation and high thermal efficiency in heat transfer problems. Extremely rugged in construction. High pressure hydrostatic tested. WILSON UNIT HEATERS Provides large volume of warm air over wide floor areas. Completely dependable in service where, corrosive atmospheres and maintenance costs are prime factors. Ask for specifications. Heating Sy,Um. . WillITY COMPANY, INC. 86 Western Avenue -- Boston 34, Mass. MANUFACTURERS OF INDUCED DRAFT FANS, DAMPERS, AND DRAFT CONTROLS 361 INDUCED DRAFT FANS B, d Used in lieu of tall chimneys; used to improve the combustion efficiency of automatic burners; used to ' correct inadequate draft. - Furnished in 22 models with capacities to 24,000,000 Btu boiler output. A size to match every boiler and beater in the Commercial-Industrial range. Fan housing is mounted on a rigid structural chassis in either a clockwise or counter-clockwise rotation; with a choice of vertical, horizontal, or angular dis charge. See "Time-Saver" chart below for application data. . K MULTI-BLADE DAMPERS STEAM DRIVE Inlet boxes with factory installed Dampers are available for use witb power-operated draft regulators. Add Suffix "T" to model number. Optional apparatus for regulating over-fire draft is available for shipment with Fans, Power actu ators may be ordered for mounting to dampers at the factory. Steam-turbine Drive has built-in speed reducer to maintain the same slow speed feature as the motordriven models. Add Suffix "S" to model number. Multi-Blade Pampers . MECHANICAL TURNDOWN ' Steam Drive . DRAFT MONITOR Turning, handwheel varies Fan speed through an automatic pulley device while maintaining constant motor ^speed. Add Suffix "J" to model number. Prevents start-up of burner unless boiler draft is proved adequate and cuts off burner whenever the draft becomes inadequate. Specify DM-3. Mechanical Turndown `Time-Saver" Chart for Induced Draft Fans Draft Monitor  362 The Will-Burt Company Orrville, Ohio Heating System! 0 t*C3 .C2 T) O CS * ^ 3 s S > gJS 5a I O --*3 -Ho-. .q05 a l.g Qo..r O s i ja ** 2 0 s -3 -g'S g S" 1 a-s g o a s s Jills ^ rs t; or* g gx # E fl *3 S 1 - 3 c .| a . '3 & >'3 5 Xi go -- 2 O ts o fin, o 2 2 . *" ? J.H'^S 5 | S-S-S8 s s1.! | 2 I g>2 JS ,, * 15 ^ I * .S 3 t a i 1 * ll"l 5 Iliyas - a t & ;f 1a . .s aj S -^3 o. . Sfol 2mM ^.o I fell 2.?! * o *o s a -3 s^ js .2 > ^ ll'P* C . SS C3o boDi md (^ai) uad S J= =s C C3 2 3 bh ** <3 G ^3 u -S igJ-- J! W5 |G 2If O fj o 5 >n i a 1 !i I i R E F E R E N C E M A N U A L . . . yo u rs to use! S p e c ific a tio n s , d ra w in g s , te c h n ic a l d a ta a n d re co m m e n d e d a p p lic a tio n s . W rite fo r fre e copy. iflfa y 363  364 Heating System* FIbra Dadi Heating Systems vm 365 CONSTRUCTION PRODUCTS DIVISION Ilartsville, South Carolina LA PUENTE, CALIF. MONTCLAIR, N. }. AKRON, IND. LONGVIEW, TEXAS ATLANTA, GA. BRANTFORD, ONTARIO MEXICO, D. F. Sonoco SoDOjurduct is a round, lightweight fibre duct that ia aluminum foil lined mid wrapped with black, asphalt filled, duplex kraft paper. It is especially designed for use as supply and return lines in gas and oil fired, slab floor perimeter heating or combination heating and cooling systems. It can also be adapted for use in spot cool ing and ventilating systemsTSonoairduct meets and exceeds FM.A. criteria and test requirements for products in this category. . Sonoairduct is aluminum foil lined for lower co-efficient of air friction. The air friction loss of 8 in. Sonoairduct is 0.151 in. of water per 100 ft at a velocity of 800 ft per minute and 70 F. Sonoairduct has a heat conductivity of 0.46 Btu per hr per sq ft per deg F per inch of thickness. This low heat loss prevents hot spots.in the slab above the encased duet. .. . Sonoairduct possesses a sound-deadening quality which minimises transmission of noise from furnace and from room to room. As the wall thickness increases with di ameter sire, Sonoairduct is highly resistant to crushing. Sonoairduct Fibre Duct is available in 23 sizes--2 in. to 36 in. I.D. Unless other lengths are specified, shipments will be made in standard lengths of 18 ft. It is easy to cut tp exact length with a hand or power saw on the job. Long lengths mean faster leveling and fewer joints to make ana seal. Sonoairduct fitB all standard metel Mnds, elbows, T's and registers. All installations should be made in accordance with Sono airduct Manual No. 557, which is available upon request. SONOAIRDUCT SIZES AND WEIGHTS AMERIVENT double-wall GAS VENT PIPE and FITTINGS For Gas-Fired Water Heaters, Boilers, Furnaces, Space or Wall Heaters Basically, AMERIVENT is a pipe-within-a-pipe. Like the familiar ther- . mos bottle, it utilizes reflective surfaces possessing low heat-radiating values and separated by an insulating air-space which prevents excessive heat loss--and draft loss--from the vent. AMERIVENTT3 thin aluminum inner pipe is designed to heat immediately to a fully-primed, fully-operat ing temperature, thus preventing condensation and dangerous spillage of waste gases into the structure through the draft hood. The heavy-gage galvanized outer pipe stays cool to protect against fire hazards and heatdamage and to permit low-clearance installation. SOEi 3*. 4'. 5'*6* r*r 10**12* *Uncr ' AVARABIC lefGTMSi 5' r irfir 6' m i 1* 1 i i Shaded area indicates available sizes Two types ofRound Amerivent--Style "E" and Style "R"--are available, depending'on the size desired. Both types carry full U~L approval, both employ a high-purity aluminum inner-pipe enclosed in a galvanized steel outer-pipe and both require only 1 in. minimum clearance from combust ibles when installed. In addition, both pipes feature the improved Ameri vent SNAP-LOCK joint. To assemble, simply press mating ends together and snap--a secure gas-tight joint is formed. A complete line of fittings is available. OVAL AMERIVENT For warm air perimeter loop systems For warm air perimeter radial systems Oval Amerivent JHSr and Round-toOval Adaptor Oval Amerivent is furnished in one model--Style "O"--in 4 in. and 5 in. sizes. It carries full U-L approval as a Type B gas vent requiring only 1 in. minimum clearance from combustibles. Style "O" Amerivent is also l/L-approved as a Type B-W vent for use only with recessed (wall) gas heaters. In this application, 4 in. oval Amerivent can be installed in a 2 in. x 4 in. stud wall if used in conjunction with ceiling plate spacers and hold-down plate. A complete line of fittings is available, including adaptors for converting to or from Round Amerivent. METALBESTOS_ Representatives and Distributors in All Major Cities METALBESTOS DOUBLE-WALL GAS VENT PIPE AND FITTINGS Gmj Vni Listed Sizes: 3 in., 4 in., 5 in., 6 in. Standard Lengths: 6 in.,.12 in., 18 in., 3 ft, 5 ft - The convenient fittings of Metalbestos RV pipe permit complete venting for stand ard or special installations ... eliminate job-site cutting>and special hand-made parts. All RV round pipe features the quick-joining Rota-Lock Coupler. QC METALBESTOS Listed Sizes: 7 in. and 8 in.; Standard Lengths: 18 iru, 3 ft, 5 ft Listed Sizes: 10 in. and 12 in.; Standard Lengths: 18 in. and 3 ft Larger-size QC Metalbestos is often required to furnish the common vent for two or more gas appliances. QC fittings are easily joined to QC standard lengths by means of die secure, die-formed QC coupler. 367 Representatives and Distributors in All Major Cities THE METALBESTOS ALL-FUEL CHIMNEY FOR -- * Appliances Burning Oil. Gas... Coal... Wood % Domestic Incinerators The light-weight, all-fuel Metalbestos Chimney installs quickly and easily... reduces job-site construction time through simple, one-man installation. Hightemperature-resistant mineral fiber and double-wall construction offer maximum performance and safety with any fuel. Exclusive Twist-Lock Coupling securely joins sections with a simple V6 turn ... without cement, mastic, or screws. De Luxe Chimney Housing (shown at left) is one of four Metalbestos Chimney Tops designed to satisfy all requirements of cost or appearance. CHIMNEY PIPE '- Between an outer pipe of galvanized steel and an inner pipe of stainless steel, mineral fiber is packed to assure safe, light-weight insulation. Combina tions of easy-to-handle 18-in. and 30 in. lengths,provide required Chimney height ID,-7"; OD, 14*. CHIMNEYSUPPORTASSEMBLY Hie sturdy Metalbestos Chimney Sup port Assembly when suspended from structural joists can easily support any Chimney height up to 53 feet In Type B gas vent installations, the double-wall insulated design of Metalbesiqs gas vent pipe prevents conden sation within the vent and spillage of combustion products at the appliance's draft hood. Rugged galvanized steel outer pipe is durable and strong. Inner aluminum pipe is corrosion-resistant, heats up quickly to create a strong ventin^.draft The built-in insulating air space prevents heat loss from flue gases as they pass through the vent to the out-of-doors. OVAL METALBESTOS Listed Sizes: 4 in. (WV), 5 in. (Crimp) '- Standard Lengths: 4-in. WV -- 6 in., 12 in., 18 in., 3 ft, 4 ft, 5 ft ` 5-in. Crimp -- 3 ft and 5 ft WV Metalbestos is designed for installation within 2 x 4 walls as Type B-W vent pipe for recessed wall heaters up to 65,000 Btu, and as Type B vent pipe for other installations. 5-in. Crimp-Joint Oval Metalbestos permits venting of larger- input appliances within 2x6 walls. . Metalbestos "Safety System" Gas Vent Tables Assure Correct Installation The Metalbestos "Safety System" Gas Vent Tables were developed by the Metal bestos Division of the William Wallace Company to- give installers a simple, scientifically accurate guide to safe, correct gas venting. Comprehensive charts cover both individual and combined gas vents and provide the information that allows installers to solve the majority of their gas venting problems. Easily read and understood, the illustrated "Safety System" Tables include ap pliance sizes and vent diameters most frequently encountered in gas vent instal lation. Copies ofthe Metalbestos "Safety System Gas Vent Tables may be obtained by writing to Dept. 9, William Wallace Co., Belmont, Calif. DELUXE AND STANDARD CHIMNEY HOUSINGS (16rx 16') The four panels of the Standard Chim ney Housing are simply assembled by means of slip-lock corners. Galvanized steel panels are easily painted, in the same manner as galvanized gutter. Prepainted De Luxe Housing (shown in complete installation above) has the same construction as the Standard Housing and IS available in attractive simulated red and buff brick. Heights: 3*. 4', 5'. ROUND CHIMNEY TOP ASSEMBLY Contemporary in appearance, the Round ChimneyTop handsomely com plements modern building design. Complete assembly includes Chimney Top, Round Storm Collar, and Round Adjustable Roof Flashing. Tall Cone Roof Flashing is available for flat-roof installations. ' This Metalbestos Chimney Caulog-Brocborc gives you complete information on the all-fuel Metalbestos Chimney. Write to Dept. 9, William Wallace Co^ Belmont, Calif. CUSTOM CHIMNEY HOUSING Custom Chimney Housing is pre-treated to permit direct paint-application/ "Shadow-Line" ridging adds extra re inforcement ... simulates pattern of brick when painted. Custom Installa tion Package includes: Top, Housing, Chimney Flashing, Firestop Spacer, Support Assembly, Starter Tee.  368 Heating Systems Pip, c*> vm DURA-VENT CORPORATION AFFILIATE OF PEERLESS MANUFACTURING DIV. OF DOVER CORP. FACTORY A WESTERN SALES OFFICE 2325 El Cambio Boat Redwood City, California FACTORY A NATIONAL SALES OFFICE 1400 W. Ormsby Ave. Louisville 1, Kentucky DURA*VENT DOUBLE-WALL GAS VENT PIPE AND FITTINGS ASSURES SAFE GAS VENTING Dura-Vent Type B. Gas Vent Systems are made of 28-gage galvanized steel outer pipe and .016-inch aluminum inner pipe. The galvanized pipe complies with the U-L requirements for fire stopping. The inner aluminum pipe is corrosion resistant to all flue gases, end it heats up quickly and maintains the proper temperature for a strong venting draft The Dura-Vent design of continuous air space on all sizes of pipe end fittings keeps the outer pipe cooler than most other types ot gas vent, and is preferred by most architects end specifying engineers. 45 ADJUSTABLE ELBOW Available in si2es 3-inch through 12-inch. A spe cial feature of DuraVent is maintenance of continuous air space in all positions of adjust- ADJUSTABLE LENGTH . Adjustable lengths are 12-Inches long and available for 3-inch size through 8-inch size round pipe. TEE Available in sizes 3-inch through 12-inch, plus a number of special re ducing tees. Consult catalog for complete details. INCREASES Increasers are used where two or more ap pliances are connected to the same vent See' Dura-Vent catalog for complete listing. DRAFT-HOOD CONNECTOR Draft hood appliance connectors are available in all sizes. APPROVED DURA-VENT TOP Engineered for maxi- mum efficiency, smart appearance and easy in stallation. Scientifically designed to help draft action. Available in all sizes. OVAL VENT PIPE AND FITTINGS STRAIGHT LENGTH Available in 4-inch and 5-inch sizes. Consult catalog for details.' Adjustable lengths are also available in 4-inch end 5-inch sizes. Dura-Vent oval pipe and fittings are furnished in the 4-inch and 5-inch sizes. All oval pipe end fittings use the simple push-snap lock, which provides a rigid joint that can be easily taken apart if necessary. The 4-inch and 5-incfa size given for oval pipe refers to no measurable dimension, but signifies that the pipe b equal in venting capacity to 4-inch and 5-inch round pipe respectively. 45 ELBOW STANDARD Standard 45 elbow il lustrated. Available in 4-inch end 5-inch sizes. 45 fiat elbow b also available in 4-inch and 5-inch sizes. ADJUSTABLE ROOF FLASHING Available in sizes 3-inch through 12-inch. ROUND PIPE The 7-inch and 8-tnch size pipe b made in the following lengths; 18-inch, 3-foot and 5-foot The 10-inch and 12-Inch size pipe b made in 18-inch end 3-foot lengths. ` Dura-Vent round pipe and fittings are made in sizes from 3-incbes to 12-Inches in inside diam eter. Pipe and fittings larger than 12-rnches can be furnished on special order. The most commonly used sizes--3-Inches through 6-incbes --use the simple push-snap-twist lock. Pipe of larger pres are locked together with screws. 90 ADJUSTABLE ELBOW Available in sizes 3-<nch through 8inch. A special fea ture of Dura-Vent b continuous air space the maintenance of' in aP positions of adjustment 1 ADAPTER. OVAL TO ROUND . Oval to round adapter illustrated. Round to oval adapter ebo avail able. These adapters available in 4-inch and 5-inch sizes. Heating Systems Cu. ou 369 VU1UUI1 UL X lcfLL, 1UC x .v. uua Combustion Engineering *rIiuieiu, ivangas TURBO-RING FORCED DRAFT GAS OR GAS-OIL BURNER provides all air for combustion under pressure ade quate to fire Multiple Pass Scotch Marine Type Boilers without Stack or ID Fan. Complete package, with Combustion Safe* guard, sequencing relays, indicating lights and switches pre wired ana tested. Natural Gas, No. 2 Oil, or Combination Gas-Oil in sixes to 200 hp. See Cat. E~SO. BLUE LINE FLAME BURNER atmospheric upshot type to convert large sire heating plants and power boilers. Cast-iron . burner heads with deep-slotted, machined ports suitable for natural gas or LP Gas under wide range of pressures. Welded manifolds to fit size and shape of fire box. On-Off, Throttling or Step-firing available. PBL Package Models to 960,000 in Col. A-tl. Larger sizes Cat. A-10. ' TURBO-FIRE POWER TYPE GAS BURNER refractory nozzles and distinctive air distribution give desired flame characteristics. Factory assembled with control panel pre wired and tested. Sizes listed for 500,000 to 28,000,000 Btu/hr. See Cat. C-10. TYPE "H" BURNER atmospheric inshot type for Scotch Marine Boilers and other applications where horizontal flame is indicated. Consists of removable cast-iron venturis with stainless steel flame retention nozzels. Natural or L.P. Gas. 33 sizes listed in Cat. H-1A. Others available on application. 1 COMBINATION GAS AND ROTARY CUP-OIL BURNER for larger installations requiring high performance operation on both gas and either light or heavy oil. Turbo-Fire Power Type Gas Burner and Rotary Cup-Oil Burner. Factory as sembled, prewired and interlocked. UL listed to 30,000,000 Btu/hr. See Cat. E-FOO-IO. GORDON & PIATT are Combustion Engineers and Manu facturers, specializing in the design and manufacture of a complete line of Gas and Combination Gas-Oil Burners. In addition to the burners illustrated, they manufacture Do mestic Conversion Burners (7 Models listed by A.G.A. and C.Q.A.). Control Panels, as cataloged, or custom-built to meet customers' requirements. Write for complete information. I ] i i Ut  370 Heating Systems Bancn, c* The Sonner Burner Company DESIGNERS AND MANUFACTURERS OF GAS CONVERSION BURNERS OFFICES AND FACTORIES : WINFIELD KANSAS Sonner Gas Conversion Burners are a product of nearly a half century of specialization in design, and manufacture. Many of the Sonner Conversion Units feature the Blue Ribbon Flame LV Burner Head with Airblend Design. Bach ribbon of flame receives all the oxygen it needs to support complete effective combustion--from both sides along its full length--because the extraordinary Sonner Airblend Design provides just the right amount of secondary air in the right places. Catalog 58-L-S gives complete description of this efficient blue ribbon of flame. A wide range of designs provides a Sonner Burner for do mestic, commercial, or industrial use. Sonner engineering serv ice is always available for consultation; write for catalog con taining complete line. Type LVS Step-Fire Burner assemblies for large heating plants and power boilers where load varies to such extremes as to make this operation desirable. Three step control is the usual arrangement although it may be altered to meet engi neers' specifications. Standard assemblies using the Sonner Blue Ribbon Flame LV Burner head with airblend design which provides just the right amount of secondary air to support complete and effective combustion, capacities for 1,440,000 to 7,200,000 Btu/hr are described in Catalog 67-LVS-l. Larger ca pacities available; consult Sonner engineering service. Type L-l Heat Mylim* is designed specifically for the con version of residential heating-plants, either round warm air furnace or a rectangular boiler, to gas. Completely automatic burner, using the Blue Ribbon Flame LV Burner head with air blend design, is A.GA. listed. Available in two sixes with ca pacities ranging from 75,000 to 400,000 Btu/hr. See Catalog 68-L-t. Type WX-55 Sonner Burner specifically designed for re placing email gun type oil burners in domestic furnaces and boilers. A.GA. listed with inputs ranging from 75,000 to 200,000 Btu/hr. See Catalog wX-55-t. Type R Sonner Burner with horizontal flame for conversion of scotch marine boilers and similar equipment to gas and stand-by fuel applications. A multiple-venturi burner in fac tory built fully assembled form. Standard assemblies from 240,000 to 7.200,000 Btu/hr. See Catalog 58-R-l. Larger capaci ties available; consult Sonner engineering service. . Gas-Oil Unit for commercial and industrial boilers, two fuel burning units, each designed for one fuel only--natural gas . nH jjght fuel oils. For capacities 'from 280,000 to 2,800,000 Btu/hr input; See Catalog 6t-CU-l. Larger capacities avail able; consult Sonner Engineering Service. Heating Systems op 371 THE CARLIN COMPANY 912 SILAS DEANE HIGHWAY WETHERSFIELD 9, CONN MANUFACTURERS OF OIL BURNERS AND OIL-FIRED HOT WATER HEATERS Pressure-atomizing, fully automatic, gun-type Oil Burners for residential and commercial in* etallations. ` The Carlin Company manufactures a complete line of quality oil burners in capacities from 0.65 to 20.00 gpb for use of No. 2 grade fuel oil. Pedestal and flange mounted models are offered. Suspension mounting to popular makes of boilers and furnaces is made easy with a wide selection of flanges and mounting fdates especially developed by U.S.-Carlin. Advanced design eatures include the "Shell Head," a significant improvement in oil burning which develops higher combustion temperatures, makes heat-wasting soot deposits negligible, conserves fuel. With either distillate or catalytic fuels, operation is quiet, clean, economical. Generous use of heat and corrosion resistant alloys guards against deterioration--cleaning easier. U.S.-Carlin Oil Burners are available with Electronic Controls which comply fully with Underwriters' Labora tories latest safety switch timing requirements. Many types are factory mounted and wired to insure proper hook-up and save on-the-job wiring expense. For complete technical literature including consulting en gineers' manual, specification sheets, electronic control data, combustion chamber dimensions, etc., address The Carlin Go., 912 Silas Deane Highway, Wethersfield 9, Conn. CONDENSED SPECIFICATIONS MOTOR--Long-hour duty with safety overload control. Complies with NBMA mounting specifications. W> hp. (Models 400,150F, 400S, 150SF-2, 500S-35); H hp. (Models 650, 700S-35, 800S-4); y* hp. (Model 1200); H hp. (Models 2000S-5, 2000). TRANSFORMER'--Shielded to block radio and TV inter ference. 10,000 volt (12,000 volt on Models 2000S-5,1200, 2000). AIR TUBE--Steel with beat resistant air cone. FAN--Precision balanced. Mounted directly on motor shaft. NOZZLE--Stainless steel alloy. Hollow cone spray (Hollow cone or solid spray on Models 1200, 2000). Dual nozzles on Models 500S-35, 650, 700S-35, 80OS-4, 2000S-5, 1200, 2000. FUEL UNIT---Single-stage standard on Models 400, 150F, 400S, 150SF-2, 500&-35, 650. Two-stage on Models 700S-35. 800S-4, 2000S-5, 1200, 2000. Built-in strainer and pressure regulating valve. Capacity of strainer equals or exceeds maxi mum firing rate of burner. . SOLENOID VALVE--Combination delayed-opening and in stantaneous cut-off oil valve standard on all "S" models, also 1200,2000. COMBUSTION HEAD--Models 150F, 400, and 650 have standard head with diffuser vanes formed at a fixed angle to establish air pattern. Model ISOF (035 to 135 gph capacity) and Model 400 (0.65 to 1.00 gph capacity) have a series of ad- I'ustable openings in center of diffuser for regulating air de- ivery to shape the fire. All "S" Models have "Shell Head" and finned collar for efficient mixture of air with oil. Models 1200, 2000 have High Temperature Combustion Head with finned collar for greater firing rate (Model 2000) and narrower fire. --ELECTRODES'--Nichrome steel with full-glazed.porcelain insulators counterbored for utmost safety. Flared, "Wide-arc" design permits heavier spark and assures positive protection during low voltage periods. BUS BARS--Rigid heavy-gage brass (Models 400. 400S, 500S- 35,700S-35,800S-4); phosphor bronze (Models 150F and 150SF2); high tension leads (Models 650, 2000S-6, 1200, 2000). HOUSING--Cast iron. Designed to assure efficient air de- livery and quiet operation. Machined to rigid standards. COUPLING-jUoiversal type with neoprene center piece. (Flexible typtfon Models 2000S-5,1200,2000). CONTROLS--Thermostat, Limit Control, and Stack Relay. Electronic Control set in place of Stack Relay on Models 8008-4, 2000S-5, 1200 and 2000. ELECTRICAL CHARACTERISTICS--115V-60 cycle. 1725 rpm. All models except 150F and 150SF-2 available with230V-60 cycleonspecial order. Also a complete line of 110 and 220V-50 cycle models with capacities from 0.50 to 15.00 gph. MODEL 400 0.55 to 4.00 gph Also available for flange mounting MODEL 400S 0.75 to 3.00 gph Also available for flange mounting MODEL 150F 0.55 to 2.00 gph Also available for pedestal mounting MODEL 150SF-2 0.65 to 1.35 gph Also available for pedestal mounting MODEL 500$-35 3.00 to 4.50 gph MODEL 700S-35 . 3.50 to 7.00 gph MODEL 650 3.50 to 6.50 gph MODEL 800S-4 4.00 to 8.00 gph MODEL 1200 MODEL 2000S-5, 7.00 to 12.00 gph 6.00 to 12.00 gph MODEL 2000, 10.00 to 20.00 gph ttS.-Cadia Oil Burners are listed by Ui*nrriUrt' LcbvrsLria, Imc. and are approved under U. 8. Cowan*it! Cemnwrcfei gJctndard C57J- U. Grade of fuel oil recommended ia No. 3 U. 8. Cowman**! Com- aurriol SttndtuV CSlt. ;  372 Healing System* oa Enterprise Engine & Machinery Co. A SUBSIDIARY OF GENERAL METALS CORPORATION 18th & Florida Streets, San Francisco 10, California Distributors in Principal Cities ENTERPRISE BELT DRIVE HORIZONTAL ROTARY BURNERS TYPE A OIL BURNER A fully automatic burner equipped with either gaa-electric or oil-electric ignition system. Firing rate controlled by either modulating or two position control meter, with low fire start. TYPE I OIL BURNER Manual--To be started, stopped and regulated by an attend ant. Semi-Automatic--To be started by an attendant. Firing rate controlled by either modulating or two position control motor. COMBINATION GAS-OIL BURNERS Three types of burners are available depending upon the method of starting the burners: . Type AY is furnished with gas-electric ignition and pro gramming type safety combustion controls to provide full automatic operation. Requires manual re-set of control only after safety shut down. . Type AY-1 is furnished with manually operated gas-electric ignition and combustion safety control. Requires manual re starting after shut down due to any cause. Type AY-2 requires manual starting and torch ignition of main game on oil or pilot flame on gas. Utilises combustion safety control which requires manual starting after shut down due to any cause. APPROVALS All Enterprise Burners are listed by UndervmLers' Laboratorits, Inc. and approved by Canadian Standards Association and many state and civic safety authorities. FUEL Burners are listed to burn oil not heavier than Commercial Standard Grade No. 5 without electric oil preheater and C.S.G. No. 6 when equipped with electric oil prebeater; also natural, manufactured, or liquefied petroleum gases. Minimum required gas pressures of 2 to 5 in. water column, depending upon burner size. DESCRIPTION Burner utilises standard electric motors with single- or mul tiple V-belt drive to provide full burner rating at any frequency of electric power. Available for either single or polyphase power, voltages of 110, 208, 220, 440 or 550 at 50 or 60 cycles. All listed types of electronic safety controls available. Burner may be furnished with integral fuel oil pump, with integral metering pump, or non-pump with separate pump set. Type AY--Combination Gas-Oil Burner Type A--Automatic Burner witbout Electric Oil Heater Type A--Automatic Burner with Electric Oil Heater Tvpe I--Simple Manual Type Burner Ratings are based upon the combustion of fuel having heat contents of 150,000 Btu per gal for oil and 1000 Btu per cu ft for gas, both at 75 percent efficiency. Outputs are based on the requirements of 970 Btu per lb of steam, 33.500 Btu per boiler hp, 240 Btu per sq ft of steam radiation and 150 Btu per sq ft of hot water radiation. When using lighter grades of fuel oil, burners will handle an increased oil input sufficient to maintain the nnmtk total heat output as for heavy oil. Heating Systems it urn, Cu and Oil 373 INDUSTRIAL^ COMBUSTION INC. EXECUTIVE OFFICES! 4507 N. OAKLAND AVENUE, MILWAUKEE II, WIS. FACTORY: MONROE, WIS. COMMERCIAL INDUSTRIAL BURNERS ENGINEERED TO FIT YOUR EXACT NEEDS HEV-E-OIL BURNBIS for No. 4, No. 5 and PS 300 OILS COMPLETE SIZE RANGE 5 gpb or 720,000 Bto GAS INPUT to 150 pph or 21.000.000 Bto GAS INPUT. FOR BOILERS UP TO 4B0 hp HEV-E-OUTY POWER GAS BURNERS (or NATURAL GAS or IPG . . . COMBINA TION LIGHT or HEAVY OIL MODELS HEV-E-OIL BURNERS for No. 4, No. 5, ond PS 300 OILS. Larger models use No. 6 oil. AL2C-- AM2CH -- AM3CH --AM3CF AM4CH -- AM4CF AM5CH-- AM5CF AM6CH -- AM6CF AM7CH -- AM7CF AM8-E AM9-6 22,400 33,600 56.000 84.000 A12C mu MtenoapalU-Honoywoll RAH7A dock eutnl. CbeSco ol M-H RA&90C Of F?teyo FI2 electronic caatroli oe Modoli 2 tbroagb 7. *~ *uSd**1 8 9 bera 6 oU` toetocy-eqolpped with beaten, bore Industrial Combustion burners operate* on die principle of low-pressure air-atomizadon and furnish all the air necessary for complete combustion. Uniform, high effi ciency is obtained at all times regardless of weather. Built to utilize the fuel lowest in cost and most read ily available, these commercial-industrial burners are factory guaranteed . . . sold and serviced throughout _the world. Fully approved, they meet all codes and Laboratories standards. * ^ COMBINATION BURNBIS r OIL (No. 4, No. 5, PS 300} HEV-E-OUTY POWER GAS BURNERS for NATURAL GAS or IPG Maxlmom Nat s Mm2! Gaa treat Max. BTU Bailor Max. HP Srondlag RocCelloa Stoaai Water p 02 720.000 '*' 16 1,750 2,800 *C3 1.580,000 35 3,800 6,000 6 04 2,500,000 56 6,100 9,800 G3 3,600,000 80 8,750 14,000 C6 5.750.000 .. 128 14,000 22.400 j G7 8.600,000 192 21,000 33,600 G8 14.300.000 320 35,000 56.000 09 21.000,-000 480 52,500 84.000 COMBINATION BURNERS FOR LIGHT Oil ond GAS 720,000 .1,580,000 2.500.000 3.600.000 S.7$0,000 6.600.000 14,300,000 21.000,000 Standing Radiation Stoam Water 1,7SO 3,800 6,100 8.750 14.000 21.000 35.000 S2.S00 2,800 6,000 9,800 14.000 22.400 33.600 56.000 64.000 Modal AMG3 AMC4 AMOS AMG6 AMC7 AMG6 Max. BTU 1,580,000 2,500,000 3,600.000 5,750,000 6.600,000 14,300.000 21.000,000 3.80 6.10Q ' 8,750 14.000 21.000 35.000 52,$00 Firaya F12 oloctronk control! ttoideto oa oil bomon. *Modoti 8 cad 9 born No. 6 ell. Slnste tool ebaaga-ovor. COMPLETELY AUTOMATIC SAFE... LATEST ELECTRONIC CONTROLS AUTOMATIC ELECTRIC IGNITION LOW FIRE START EASILY MAINTAINED COMPLETE... READY FOR INSTALLATION FACTORY FIRE TESTED POSITIVE FUEL SAVINGS SUPER-SIMPLE INSTALLATION / Write for free copy of "ARCHITECTS and ENGINEERS HANDBOOK" Descriptive BULLETINS I ond 2 mailed on request.  374 S. T. JOHNSON CO. Heating Sjrttem* 940 Arlington Ave., Oakland 8, Calif. J"ofauon ft <M WlVUWlS . Church Road, Bridgeport, Pennsylvania S. T. JOHNSON CO. 375 940 Arlington Ave., Oakland 8, Calif. Ioh/uon BM UAtWIA Church Road, Bridgeport, Pennsylvania BANKHEAT BURNERS Pressure atomizing type. Fully automatic electronic controls. Built with the heat saving air-shut-off feature which prevents cold air from passing through the burner, firebox and flue when burner is not in operation. Pump-driven oil is forced through orifice, pressure-atomised and mixed with whirling jet of fandriven air, to bum with a soft clean flame while suspended in air. Notable for exceptional efficiency, fuel-economy and trouble free performance. Adaptable to most domestic and commercial halting needs. Particularly suited to use for "conversions.'* Easy to install and service. Water Heaters, Boiler-Burner Units, Hot Air Furnaces Johnson Water Heaters, Boiler-Burner Units and Hot Air Furnaces powered by Bankheat Burners are available in. a wide range of sixes and types. Descriptive literature on any item may be had on request. BANKHEAT Combination OIL-and-GAS BURNERS Will automatically bum cither oil or gas with high efficiency. An ideal installation for areas where low-cost gas is available only on a part time basis. You can change from one fuel to the other with a flip of the changeover switch (either manual or, at small extra cost, automatically controlled by outside temperatures). Sizes and Capacities. Bankheat Burners SIZE MAX FIRING RATE MAX BOILER OUTPUT Oil gpb Gas CFH 1000 Btu Steam Sq Ft Water Sq Ft HR 0 315 900 1450 6X 0A 3 420 1300 2100 9 IA 5}* 770 2300 3650 16 2 1050 3100 4950 22 2A 10 1400 4150 6650 30 3 15 2100 6200 9900 45 3A 18 2520 7500 12000 54 FORCED DRAFT BANKHEAT BURNERS Fully automatic, for Firing on OIL only. GAS only, or COMBINATION OIL-and-GAS Built to deliver all the air needed for combustion without the aid of an induced-draft fan or tall chimney. A special back ward-curved fan rotating at twice ordinary speed drives this, air with a minimum of pulsation in the air stream delivered to the combustion chamber. With Bankheat Forced Draft Burn ers there are few pulsation problems on "hard to fire" in stallations involving either positive or negative firebox pres sures. . , Made in 6 basic sizes: 30, 40, 60, 80 and 100 hp. These ratings are based on positive firebox pressures up to 0.75 in. wc. These units are easily wired, installed and serviced. Flange mounts are furnished. According to Type and Size, each burner is equipped with Straight-Electric or Gas-Electric ignition, with Electronic Controls to suit. Model 53 Burner Model 53 Burner with Belt Drive Model 53 Combination Oil.and-Gas Burner 53JOHNSON MODEL METERING PUMP BURNERS Fast Positive Starting. Smooth Operation. Greater Fuel Economy. These rotary-type burners were designed to produce sure, automatic "starts" even when the oil in storage tank and lines is cold and hard to pump. This important performance feature was accomplished by using a positive-displacement Metering Pump,... a 3-Way Magnetic Oil Valve, . . . and a high efficiency Suction Pump, which enable Modei 53 Burners to maintain, automatically, a fixed air-fuel-ratio regardless of variations in oil temperature and viscosity. They are easy to set and to control. Firing Rate can be de termined by reading the setting of the Metering Pump Quad rant. All working parts are quickly accessible for servicing or repair. The fuel economy and reliability of these burners been thoroughly established in every type of heavy duty service throughout America and numerous foreign countries. Model 53 Burners are available with either conventional Direct Drive or with Belt Drive for use in installations using 50 cycle current to maintain 60 cycle speed, . . . and on in stallations where additional capacity is required. They are available for firing'on Oil Only, Gas Only, or as Combination Oil-and-Gas Burners. There are 9 sizes ranging from 28 to 660 hp and from3980 to 78600 sq ft Steam Radiation. SIZES AND CAPACITIES. MODEL S3 Burner Sits* BTU Output (1000 Btu) J METERING s> o PUMP CAPACITY & GPH {BURNER RATING <3 it0. a s 2 bi s 8 a I is g-c 11 jjo ? .5 I cu S3 fi Em e 3 gtl. 0. U.Q b>Q sT zs h 50 h 75 H 100 1 150 1H 300 2 300 3 400 4 600 W 2 3 3 2 3 3 5 6 10 40 40 60 80 135 135 190 190 32$ 7.5 9.5 8.5 15 18.75 17 33.5 35.12 35 30 37.5 34 45 50.25 SO 00 75 a? 90 112.5 100 130 150 135 150 187.6 158 38 67 83 113 107 325 333 450 560 985 3980 0380 950 (90S 7950 17750 1913 3900 11700 18750 3313 3930 15050 35500 3835 5800 33400 37S00 S625 7750 31400 50200 7538 11500 48800 75000 1US0 15800 632S0 101300 15188 19400 78S00 136000 18900 obtained *t metering pomp artting of 1. .i0f.-------------"* n {Maximum metering pump capacity aetiiag 1.25 ia maximum firing rata. Burner ratine iabawd onraafio conditions of draft, combustion volume and oocnbcation chamber design. Undm lavurablo conditions, it may be permisihle to use maximum firing rate. Under restricted conditions, it may be desirable to os* reduced firing rates. Ratines based on 150,000 Btu/cal and 75 percent effi ciency. For use with f J to 6 8 C-S.G. Fuel Oil. COMPACT FORCED DRAFT Package Unit BURNERS Built for firing on Oil Only, Gas Only or as Combination Oil- and-Gas Burners. Two types are available for use on Scotch Type or Firebox Type boilers. They are engineered to provide all the air needed for proper combustion regardless of stack conditions and firebox pressure variations. All these. Forced Draft Package Units are factory-assembled, wired and tested, complete with all the controls mounted in dust type cabinet, reaay for fast, inexpensive installation on any standard size and type of boiler. They are available in the sites and capacities listed above for Johnson 53 Burners. SHEETS GIVING CATALOG DATA AND SAMPLE SPECIFICATIONS ARB AVAILABLE ON REQUEST  376 Heating Systems Batun, Oil n4 C< THE METTLER CO., Inc. 1101 Buchanan St., Rockford, 111. Division of Eclipse Fuel Engineering Company Packaged burners for gas or combination gas-oil firing rated up to 800 bhp output have been designed and built by Mettler for more than 35 years. FAN-AIR GAS BURNERS For forced, induced or natural draft operation in large and small power plants with capacities from 1,300,000 to 35,000,000 Btu input. Eight largest stand ard size burners are equipped with enclosed eontrol cabinets. Details in Bulletin G-S00-B. FAN-AIR COMBINATION GAS-OIL BURNERS With output ratings of 25 to 800 bhp, change fuel at the flick of a switch located either on burner or at re mote station. Oil-gas internal assembly combines gas pilot, oil nozzles, spark rods, flame rod, photo-cell and stainless steel Turbo-Fins in a single compact unit for adjustment or cleaning. Details in Bulletin GO-S00-B. TURBO-FLAME BURNER Is a single port nozzle mixing burner for gas, oil, or gas-oil combination firing. Designed for use on Scotch marine boilers where back pressure or positive pres sure exists or is likely. Capacity ranges from 500,000 to 5,000,000 Btu/hr depending on back pressure. De tails in Bulletin GO-S00-B. Other standard Mettler burner lines include the-Series "C" entrained combustion gas burners and Mettler junior "Fan-Air" burners rated at 150,000 to 1,400,000 Btu input. Literature on both lines available. Heating Systems Cumti, Oil ml Cat RAY BURNER COMPANY 377 Since 1872 1301 San Jose Avenue; San Francisco 12, California Atlantic Seaboard Div.; 629 Grove St., Jersey City 2, N. J. Distributors in All Principal Cities of the World RAY FORCED DRAFT PACKAGED BURNERS -*'<------- -- -- A factory assembled unit readily applied to any type of boiler designed for forced orait operation. Fully automatic operation on oil, gas or combination gas-oil. The combination gas-oil unit includes a rotary oil burner, integrated ring type gas burner, secondary air control with a forced draft fan, windbox, refractory support ring completely wired control cabinet and pre-piping completely factory assembled for quick and easy installation to the boiler. . Oil components may be selected to bum any grade of oil with the secondary air con- txol providing increased efficiency even with the difficult-to-bum catalytic residual S6 fuel oils. Sizes 1 to 10. From 40 to 750 developed output horsepower. RAY COMBINATION OIL-GAS BURNERS ARC-MODEL 550. Consists of a rotary type oil burner of Ray conventional design coupled with a gas housing for low pressure gas. The gas burner parts provide for the introduction of gas in a manner which fully utilizes the energy in the high pressure air supplied by the rotary burner fan. Gas and primary air are.intimately combined, in two stages, before mixing with the secondary air which is introduced through a vaned annular opening concentric with the nozzle. Change-over requires 1hb thin one minute Available to bum any grade of oil; 9 sizes with capacities to 31,500,000 Btu/hr Gravity type to 48,000000 Btu/hr. /nr uy TYPE PCP. Fully automatic combination gas-oil burner of the pressure atomizing type. Available in three sizes with capacities from 560,000 to 4,200,000, Btu/hr. High speed 3450 rpm models available for forced draft operation. Also available for straight gas operation, as type PG.* `- RAY DOMESTIC AND STEAM TURBINE BURNERS RAY HORIZONTAL ROTARY OIL BURNERS RAY PRESSURE ATOMIZING OIL BURNERS. Fully automatic for H2 oil or lighter. 4 sizes with capacities from I to 30 gph. Pedestal or Flange mounting. Ail types have electric ignition inter rupted or constant. AC or DC. Electronic controls are standard on all models above 7 gph capacity. High speed 3450 rpm models availiable for forced draft operation. proved far D. 5. /Ywy RAY INSHOT GAS BURNERS Multi-jet atmospheric type gas burners with high flexibility in nozzle number, arrangement and capacity, permitting high input ratings in limited space. For commercial and industrial application with natural or induced draft. Available in 36 different jet arrangements with capacities from 99 to 7512 cfh. Star 2, IC-29 Built in fuUy automatic, semi-automatic and manual types; in sizes from 7 to 1000 Boiler hp, 230 to 37# Ibs/hr, to bum all grades of fuel ml. standard models include both direct and belt drives--the latter being recom mended for use where other than 50 or 60 cycles AC, or only DC is available. Types tor diesel electric or gas electric ignition; pump or gravity feeds. Direct drive types include a steam turbine driven model. ' Most fuUy automatic types for heavy oil incorporate the Ray Dual Pump and Res ervoir, with the Ray VISCOSITY Valve, a patented, exclusive feature which auto matically meters the correct amouot of fuel at all times, regardless of changes in viscosity of the ou due to temperature variations. All larger aea employ dual igni tion system, consisting of dual high-voltage transformers, dual electric ignitors and dual gas valves. Fully automatic burners include as standard equipment electronic pilot and flame failure control as required by code. RAY BURNER HOURLY CAPACITY RATINGS Burner Site Is a Oil Capacity U. S. CaUona i-pL j-pf'* j-pJ B H 14 0 H' iH s 4 K" 5 0 1H 7S 8 k10 IS 4 7 14 S 4 8 8 10 IS 14 S4 zs 40 74 7 18 30 4 11 14 ts 34 40 70 110 140 110 330 Equi relent BoOer HP Mia. 3 13 S3 44 0 33 44 04 7 IS 13 34 17 40 37 83 S3 110 40 104 40 330 S3 305 no 600 104 700 340 1000 Equivalent Lb*. Steam Generated+ 110 430 745 1510 330 460 480 930 1100 1400 1740 3900 4040 UfB 8700 335 745 IUQ 3340 480 UTft 1740 3900 OSO 5800 8100 13700 17400 34400 87000 Heat Capacity Input Thou. Btu OU or 1000 Btu Gas Min Max. 140 420 500 1000 1000 2SOO 1900 4200 800 740 800 1080 750 3340 1300 3750 1400 1800 3240 3780 4349 7400 10500 1(400 urtasno 33400 31400 48000 Equivalent Sq. Ft Steam Hadiailnn 440 1750 3060 0130 938 1880 3340 3750 4090 sea 7030 11700 10400 33400 34100 1300 8060 7900 13140 840 JIM 7030 117*0 18400 33500 33800 61400 70S00 98300 149300 om11p0iea,rt0ia*b0St0eHlteeBa,ahttmuuprnecpoddaeunepcrrbeacdedecelilsrttoyaidrtfaberobiasvila.eeleHlnocdeormoanpntodirndiettgeiesola*Aan.mr*pe,ataFodtotaoimnapedtizraaAinrteegj"5Mlba*boatPutahoer.irndgebhurpep*roamrnnaadt*1ey6n*u0b,p,h0eoo0prni0sacaBodrnnetvuaoibsovpaeeeebldtirlaedfguorauirbvlnafeodoinfelrecormeriredlmoffdfodticerrriibacreo.tfnettcadoyrpycoeefbrna7u4dtrioUnpneeio.rr*ucaeTnntotd.  378 Heating System* PETRO 3242 West 106th Street, Cleveland 11, Ohio Quality Heating and Power Equipment since 1903 INDUSTRIAL AND COMMERCIAL OIL AND GAS BURNING SYSTEMS FOR EVERY NEED LARGE CAPACITY BURNERS, MODELS P-90, P-90E, P-200, P-200Et In to domestic heating in large residences, these Petio hnrpen have a wide field of application in many commercial and public buildings such as ^schools, cburcnes, . ' "PACKAGED" COMMERCIAL OIL BURNERS--FOR FUEL OILS UP TO AND INCLUDING HEAVY NO. 5 Here at last is a reliable gun type low pressure burner mat will fire No. 5 oils or any lighter grade, using die superchargertype fuel atomizer. Atom ization is so complete that electric ignition can be used in place of the gas flame required by other burner types. The ability to fire heavy or light oils, and to modulate over a wide range, makes this burner unique in its field. Capac ities are from 3 to 25 gph. PETRO COMPLETE "PACKAGED UNIT* Consisting of Burner (for oil or gas or both). Fuel System, Control Panel, and Pre- CAPACITY OF PETRO PRESSURE ATOMIZING BURNERS Burner Nozzle Size Model Cels, per Hr. Total Capacity* Steam Sq- Ft. Hot Water Sa. Ft.** P-80 P-90E P-200 P-200E P-S00*** 5 to 8 5 to 9 0 to 20 9 to 20 20 to 30 1750 to 3150 2300 to 5050 1750 to 3150 2800 to 5050 3150 to 7000 5040 to 11200 3150 to 7000 5040 to 11200 7000 to 10500 11200 to 16800 260 Total capacity equab funding radiation, plus piping low, pins pickup,' plus hot water. Rating based upon water at 170*F in radiators. Standard with electric controls giving two-eeeead tbot-down. NEW COMMERCIAL FORCED DRAFT PACKAGE BURNER --FOR OIL, CAS OR DUAL-FUEL--P-240 GOSM Here is a completely new commercial pres sure burner which offers l two distinct features: 1 forced draft operation and freedom from pul sation. All necessary operating controls, in cluding an electronic combustion control sys tem, are integral com ponents. The units are complete fuel burning- systems--assembled, wired and tested at the factory. Air for com bustion is supplied under pressure by a highly efficient blower. Burners are available in two types of construction: fan housing above or below the draft tube. Models with ran noosing below the draft tube are particularly adaptable to Scotch-Manne type boilers, as no burner parts project above the draft tube to interfere with boiler cleanout doors. Installation is simple. Capacities range from 8 through 24 gph for oil and for gas from 1,200,000 through 3,600,000 Btu input- This Petro package unit is much more than a conversion burner. It's a complete combustion system in which all elements are cor rectly haltmred and integrated--a thoroughly engineered firing S* t Includes burner (for oil or gas or both), fuel system, forced t air supply, control panel, and pro-formed refractory com bustion throat Installation requires little more man bolting the entire unit to the boiler-front and making service connections for power and fuel: This represents a substantia] saving in in stallation time and cost--but even more important it weans a factory tested and assembled unit for high operating efficiency, and fuel savings. Control panel is totally enclosed, with all instruments wired and tested at the factory. The units are designed for easy application to all types of boilers including the Scotch Marine. They operate either under normal firebox draft conditions or under positive pressure w sealed firebox boilers which are designed for operation under furnace pressure. Oil capacity--25 to 145 gph (No. 6 or lighter) and equivalent ratings in gas. Boneri, OO and Gsa PETRO 3242 West 106th Street, Cleveland 11, Ohio Quality Heating and Power Equipment since 1903 379 INDUSTRIAL AND COMMERCIAL OIL AND GAS ^ BURNING SYSTEMS FOR AUTOMATIC, SEMI-AUTOMATIC OR MANUAL OPERATION , FOR UNHEATED COMMERCIAL OILS ic^ronized < Model W-A: Automatic ignition with syn oil and air. FOR HEATED OILS: HEAVY NO. 5 (MODEL W-A-E); BUNKER "C" NO. 6 (MODEL W-AH) Models W-A-E; W-AH: Automatic ignition with synchronized control of oil and air, and automatic control of oil heaters. ALL PETRO MODEL W ROTARY-CUP OIL BURNERS: A Petro Model W consists of a self-contained assembly of fan, pump, rotajy cup atomizer and all oil and air adjustment ap paratus. It is either direct-driven by means of a built-in motor, or belt-driven from motor mounted on burner- bousing. Inter locking oil and air control mechanism permits operation at any point within the burner's minimum and maximum range. CAPACITIES OF PETRO MODEL W OIL BURNERS AT-75% BOILER EFFICIENCY W-2* W-3 . W-4 W-5 YV-6 W-7 W-8 W-Stt W-9 W-1Q Minmma Cab. Per Hour' 100 120 145 B.T.U. Release Per Hour 1.650.000 2.250.000 3.750.000 5.250.000 10,500,000. 15,000.000 16.000.000 21.750.000 30.000,000 Rated Capacity Steam Radiation Boiler Sq.Ft.EJXR. Horsepower 50.4 83.8 117.3 167.5 34.2 335.0 403-0 486.0 670.0 32.800 56.200 83.600 INDUSTRIAL COMBINATION GAS-OIL BURNERS USINC NATURAL AND INDUCED DRAFT: * Model WG Industrial Gas-Oil Burner will fire low or high pres sure natural gas or any grade of fuel oil, with natural or induced draft. It is a fully integrated unit in which primary air for com bustion of both oil ana gas is supplied by the oil burner fan. Secondary air is admitted around the burner opening, eliminating the deep firebox pit and brick checkerwork required in the con ventional rotary oil burner setting. Enclosed control panel, with instruments installed, wired and tested at factory, may be Hiounted at burner or on boiler room wall. Fuel change is ac complished quickly by electrical switching. Oil capacities, H to 120 gph; gas 1,650,000 to 18,750,000 Btu input Model WC Burner Combination gas-oil, with Petro rotary oil burner (direct or belt drive) integrated with gas burner, air register and * precast refractory combustion throat Modutrol Ere control added if desired. Complete gas-oil firing system fa single New Air Register Readily coaverts any Petra Rotary Oil Burner to combination gUroil fir ing. Kit includes register, gas controls and standard parts groups. A minimum of installation time required. Air regis ters available also for straight oil firing. INTEGRAL AIR REGISTER CONVERSION KITS: ^ The Petro Air Register is ideal for converting oil installations to gas^nl. The rotary oil burner bolts on the register making an easy field conversion that is complete with refractory, combustion throat and the gas ring. All combustion air is admittwl around the burner opening as required by Underwriters' Laboratories , standards. . ' * All Petra Model W burners are available in either direct- or belt-drives motor type*. o380 Heating Systems #. on YORK-SHIPLEY, INC. MAIN OFFICES AND PLANT, YORK, PA. OIL AND/OR GAS-FIRED tVbaKjjiyf^wlR) EQUIPMENT FOR INDUSTRY STEAM-PA.K GENERATORS High or low pressure steam. No. 3, 5 or 6 oil and/or gas firing. Fully automatic operation ______' Mode) No. SPH-10 BP-63A-15 SP-53A-20 8P-84A-30 BP-40 BP-60 SP-60 BP-75 BP-60O-8. SP-tOO-O.8. 8P-100 BP-125 BP-66-180 BP-200 8P-250 SP-300 SP-350 BP-400 SP-800 SP-600 NcbkbiI HP 10 15 20 30 40 80 60 78 80 IOO JOQ 12S 180 ` 200 280 300 380 400 800 800 Steesa Lbs/Hr 345 r6a2o5 1035 1360 1725 2070 2587.5 2780 3450 3480 43U.5 6173 8900 8825 10350. 12080 13800 17280 J0700 EDR Sq Ft Steam 1397 2100 2780 4250 5583 7000 6378 10489 11)60 13988 0986 17447 20037 27918 34895 41874 <8800 65800 69500 83700 H la. 44* mi 58* 88 TIM 71* 78 78 78 83* 8314 88* 115* 118* 118 US 128 138 133 W la85 i. 6lH. 61W* as 7I}4 75* 73* 91* 91* 93 103* 107* 114* 114* L In. '* 90* 90* 118 122 137 , 1S$* mi 151* SB 193* 187* 310 , 247* 247* 277* 289* 286* 292 YORK-POWER HOT WATER BOILERS Designed specifically for hot water heating applications. No. 3, 5, and 6 oil and/or gas-firing, Fully ' automatic operation High or low pressure steam or hot water. No. 3, 5 or 6 oil and/or g firing. Fully automatic operation ' Model No. EDR Sq Ft Hot Water He*TDoty 8Pi7-A-& SP-67A40 SP-67-A-M SP-S7A-40 Beeobr Doty sp-saio SP-56-1SB SP-63A-15 8P-S3A-20 SP-54A-30 BgPp--8s5i-^4o0 1397 1100 MOO SralOoO MOO 4800 <183 0700 78* TIM 85* es* FIRE-PAK BOILERS ' Packaged fire-tube boilers for low pressure steam or hot water. No. 3, 5, or 6 oil and/or gas firing. Fully automatic operation. _____________ Model No. YF884140 Mfn Certified Retina Hot Water HP SEDR Sq Ft EDR H laSq Ft 4920 7890 98 8675 48 6400 10340 SI 7080 11220 78l0 12300 63 8650 138S0 100 90 19900 102 14210 22750 27040 17450 27900 20980 33800 3X500 223 31400 0200 136 280 38950 82300 <7880 7S5D0 m 483 87180 107890 175 W la. 57 L la. 96 SCOT-PAK BOILERS Packaged scotch marine boilers for forced draft,, natural draft or induced draft firing. No. 3, 5, A 6 fuel oil and/or gas. Fully automatic. - Model No. Y6M56-40 YSMtMl YSM58-S0 Y8M56A0 Y8M6S-70 Y6J1K-85 YBM56-I0O Y8M-68-1ZS Y8MA8-U0 YSM-66-17S YSM-66-200 Y8M-50-2SQ YSH-56-300 Y8M-66-S50 Mfe. Certified Ritm 012$ 10010 127S0 11000 18450 45550 M800 55300 ir ts* 73* 78* 78* 84M 84* $ SS tost* 114* 114* 56* sm SB* om 64* 7T0DHM 78* 76H Sg to<o}t** 100* 117}* 136* 143}* 133}* 1M} 187}* its* ss 201* HIM 220* 223* YORK-POWER BURNERS Horizontal Rotary burners for conversion application. No' 2, 4, 5 or 6 oil and/or gaa firing. Factory-coordinated fuel burning systems used with burners to provide fully automatic . system- Burner Model Mu GPS A-1S A-45 A-80 B-100 B-12S C-173 C-225 0-400 FriR Sq Ft Steen a Boiler Efficiency 60 percent I 55 percept 0 percent 7500 12400 15740 1440 6095 6120 13430 17080 .14380 30493 40800 54800 3830 6580 8780 14480 36680 48780 68700 Aerco Corporation Paris Avenue, P. O. Box 248 Northvale, N. J. AERCO S Controlled "IITR" (Heat Transfer Rate) Heat Exchanger is a Compact Storage Water Heater featuring an Internal Compensator which; Anticipates changes in required steam flow before the actual heat transfer takes place. Meters the steam flow accurately in direct pro portion with load. Prevents surges in steam flow, Geminating need for large storage. Maintains ACCURATE control of outlet water tem perature. Prevents OVERRIDE of outlet temperature on sud den interruption of water flow. For UNIFORMLY VARYING LOADS (i.e. Hos pital General Water Supply), the ability of the above heater to prevent steam flow surges ELIMINATES the need for large STORAGE. ' For NON-UNIFORMLY VARYING LOADS or periodic high peak flows and low average demands (i.e. Small Commercial Laundry), the AERCO COMPACT STORAGE WATER HEATER with an Accumulator and Recirculating Pump (as shown in Figure 2) gives a low cost combination which also permits: Minimum storage volume for peak demands. Minimum steam input for re quired load. Accurate controlled outlet water temperature under all load con ditions. Figure 2--Aerco Compact Storage Water Heater in combination with Accumulator and Recirculating Pump CONSTRUCTION Shell fabricated to ASME Code Standards, of Flange Quality Steel with ' plastic or copper lining. Shell ends Cast-iron or Bronze. Internal parts of ..Copper or Brass. Tested for 125 psig operating pressure. Capacities, 300 to 25,000 gph. OPERATION Cold water enters top, flows down through the Compensator, then up across steam coils to discharge at top. Steam feeds into coils through Steam Riser and leaves through Condensate Return. Compensator anticipates and controls heat transfer rate by sensing changes in flow or incoming temperature before water passes over the heating coils. It accomplishes this by causing variations of temperature to occur at the Regulator bulb which are definitely related to changes in flow and incoming temperature as well as the final temperature. Send for booklet: "THE NEW APPROACH To the Design of Hot Water Supply Systems" and Bulletin #22 for capacity data and sires. - ^  382 Heating Systems h< v, I CW/ BELL & GOSSETT COMPANY MORTON GROVE, ILLINOIS Canadian Licensee: S. A. Armstrong, Ltd., 1400 O'Connor Drive, Toronto 16, Ont. Sec. U. S. P*L 08. Hyd!`GZSrJ& HOT WATER HEATING & COOLING SYSTEMS & SPECIALTIES B A G Universal Pump B & G Booster The B & G Booster is tbe basic unit of the B A G HydroFlo Forced Hot Water Heating System. The prime requisite of such a pump is quiet operation and in this respect the B & G Booster is completely outstanding. The oversized, special alloy, mirror-finished shaft provides large, super smooth bearing surfaces. The heat-treated thrust collar, integral with the shaft, prevents end movement. Bronze, sleeve type bearings are extra long to maintain the shaft in exact alignment and help assure smooth, quiet operation. The Seal assembly provides positive protection against water leakage into 'bearings. The true centrifugal design impeller operates with a minimum of slippage, assuring a full quota of water with each revolution. BAG Boosters have a genuine oil-circulating lubrication system--another reason for quiet, dependable operation. Oil is drawn from the oil well by wool fiber wicking snadropped on the horizontal bearing surfaces. Medium grade motor oil is used, and only a few drops at infrequent intervals are required. BAG BOOSTER SPECIFICATIONS WHERE SERVICE WATER IS PUMPED, USE A BRONZE BOOSTER Standard Equinmei US Volt, 60 CycL Single Phase B & G Universal Pump ' Designed for forced hot water heating systems in apartment and office buildings, factories, schools, etc. The Universal is not an ordinary centrifugal pump, but is specially designed to assure quiet operation so essential in heating system applica tions. * BAG UNIVERSAL PUMP SPECIFICATIONS Dimensions ore subject to change. When needed for layout, write to factory for certified print.______________ "150" 144* r EDS' LOW DELIVERY HDT HIGH DELIVERY i!5XvIhigh HV,j(VELOCITY PD IS-S PDI5-T PD S7-S PDJ7-T 44 Flanged 1 Flanged 144 Flanged 144 Flanged IB Flanged 2 Flanged *44 Flanged 3 Flanged 3 Flanged 1 Flanged 144 Flanged lli Flanged 1 Flanged 3 Flanged 3 Flanged 3 Flanged 3 Flanged 4| H.P. H* H.P. Hi H.P. H* H.P. 44 H.P. >4 H.P. W H.P. 44 H.P. 44 H.P. U H.P. -I PH. b44 H.P. -3 PH. *44 H.P.- -I PH. - ** H.P. -8 PH. * Motors with special current characteristic! at extra charge ae listed in Price ^^pb-35-6 and PD-37-S are arnilabbs with 115,108 or 230 Volt Motor* and have U-1S A U-IT U-28 * U-ST U-3S A U4T U-4S A U-4T U-6S A U-5T U-8T U-7T U-ST U-BT U-10T U-llT U-12T U-13T U-14T "S" (ingle phase motors; "T", three phase motors. built-in overtoad protection. PD-35-f and PD-J7-T are available with 208-230 Volt or 4X6-480 Volt Motors. overload equipment must be provided on three phase motor*. B, & G Flo-Control Valves For preventing gravity flow in forced hot water systems and to permit summerwinter operation of a BAG Indirect Water Heater. Sizes 1,and Iin. are made in combination straight-angle patterns, and can be installed in either horizontal or vertical puoip lines. Easy cleaning is a feature of B A G Flo-Control Valves--no need to break pipe connections for removal of foreign matter. Valve Namber and Site Connections Straight-Angle Pattern 1 in.-- IH in.-lH i- Angle Pattern 2 in.--in.--3 in. SA Straigbt-aagte pattern Angle pattern Straight pattern Bronze angle pattern Bronx--airtight pattern BA l* Af 83* . ba r SB M* SA 1W' ASH' s BA 1H' SA 1H* A 3* S3' Strewed Flanged 1 end-- , clewed end 8 4' Flanged I end-- crewed 1 end - Sweat Connection* Sweat Connection* Bell & Gossett Co. 383 B & G Monoflo Fittings--Cast-Iron or Copper BAG Monoflo Fittings permit the use of a single pipe main instead of con ventional flow and return lines. Installed at the junction of the radiator risers to the single main, they assure proper diversion of water into each radiator, convector or baseboard, regardless of its position in the system. They can be installed at either the return or supply riser, with the other main connection being a common tee. CAST IRON FITTINGS COPPER FITTINGS Size Tapping Sizes, Inches Size Tapping Sizes. Inches PRODUCTS 44' 144X 44. 44 OR i *>4X14,44.1 OR 144 3 X44. 44.1 OR 144 44' 44 X 44 RETURN ONLY *144X44 OR M w 144 X 44. 44 OR l 2 X44.44 0R1 * New Red Wing Fitting! serve ee either supply or return fittings. B & G Relief and Reducing Valves BAG Relief Valves, for relieving excess boiler pressures in hot water beating systems and in the lines of water service systems are designed and built to ASMS specifications, tested by the National Board and labelled with the ASMS symbol. BAG Reducing Valves have all working parts made of brass, with built-in ' strainer and Anti-Siphon Check Valve. Adjustable to meet varying building heights. Nos. 175-250-330-480 Relief Valves Nos. 750-1050-3300-4100 Relief Valves No. In'lf. Capacity Standard Bto/Hr Setting, Lb* No. Si Capacity Bto/Hr Standard Setting, Lb 175 175.000 250.000 350 480 480.000 30 750 , 1050 1.050.000 3300 144 3.300.000 2 4.100.000 30b * Also available el 15. 36, 45. SO, 75. 100, 125 lb eettinga. * Abo available at 15. 36. 45. 50, 75. 100. 125 lb eettinge.6 Abo available at 55,36, 45, and 60lb eettinge. No. 12 Reducing Valve All working parts are of brass, with easily cleaned, built-in strainer and Anti Siphon CheckValve. Factory adjusted at 12 lbs; suitablefor 1,2 andS-etorybuildings. B & G Motorized Valves Thermostatically operated valves used to control boiler water flow through indi vidual circuits of zoned heating systems. - B & G Comfort Control System Outdoor type, wind-compensating temperature control. The Regulator projects through the building wall, with the indoor end warmed by water in the radiation circuit. A small amount of this heat is conducted to the outside end. where it is dis sipated at a rate dependent upon temperature and wind velocity. This heat dissipa tion governs the Control Valve, which permits hot boiler water to enter the system in required amounts. - . . For preventing gravity flow in forced hot water systems and to permit summer- winter operation of a B A G Indirect Water Beater. Sizes 1 in., \Ys in. and in. are made in combination straight- angle patterns, and can be installed in either norisontal or vertical pump lines. Easy cleaning is a feature of B 4 G Flo- Control Valves--no need to break pipe connectionsforremovalofforeignmatter. On all orders specify number of supply and return fittings. BAG Relief Valve BAG Reducing Valve A i 4 B A G Com fort Control Regulator and Valve B & G HEAT EXCHANGERS AND WATER HEATERS TYPE WU--A shell and tube heat exchanger with hot boiler water pumped through the shell by a B A G Booster, making possible big capacity in a small unit. Pumping water through the heater also affords excellent temperature control and permits use of much smailerpipe and fittings. y TYPE *`SU"--For heating water with-stcam. An ideal selection for industrial plants x or wherever large volumes of hot water are required continuously for service water supply or process work. No storage tank required--the large heat transfer surface in these units heats water instantly as needed. Available in a wide range of capacities. B & G Centrifugal Pumps Design and construction based upon years of experience in the industrial field. Rugged, compact units--built to withstandstrain of continuous operation. Semi-open or enclosed impellers--motors flexible coupled or integral with pump. Series 16SS illustrated. BAG Package liquid Cooler * B & G Package Liquid Coolers The only unit of its kind with all major components designed, built and guaranteed by one manufacturer. Everything included, no extras to buy--this is truly a package unit. Because of the many features iocluded as standard equipment, this unit can be in stalled at smaller final cost. A complete line of refrigeration components is also avail able.  384 Heating Systems M Wirr AMERICAN TUBE PRODUCTS, INC. General Offices: 100 Pulaski Street, West Warwick, R. I. Nationwide distribution through branches and plumbing and heating wholesalers Foreign Sales through home offices Diaphragm-type, Pressurized Expansion Tanks "O" Ring Type Expansion Joints Hot Water Heating Accessories EXTROL EXPANSION CONTROL FOR HOT WATER HEATING SYSTEMS APPLICATION The Extrol Expansion Control Unit is a diaphragmtype, pressurized expansion tank developed by Ameri can Tube Products, Inc., specifically for use on hotwater heating systems. It replaces (he conventional expansion tank. DESCRIPTION Hie Extrol Unit is constructed of two steel AJSME hemispheres bonded together in a compact, sealed unit. A butyl diaphragm or bladder separates the unit into two chambers, one of which is factory pressurized with air. Thus there can be no contact between system water and air. Mounting and piping provisions are furnished. INSTALLATION Extrol units may be installed at any point in the sys tem mid in any position. Positioning for drainage is not required. ` CAPACITY Extrol volume is based on the ASME Formula as it appears in the ASHAE GUIDE under "Hot Water Heating Systems." ADVANTAGES No loss of air cushion through absorption by boiler water Air problems in system substantially reduced . Use of compressed air to charge expansion tank re duces the required tank volume No maintenance or servicing--no draining or re charging necessary Reduces system corrosion Smaller space requirements Simpler installation Lower initial cost OPERATION As thermal expansion build-up develops in the system, water enters one chamber, displacing the diaphragm towards the other chamber and further compressing the air cushion. When water temperature decreases, the resulting contraction of water pressure allows the air cushion to deflect the diaphragm, returning water to the system. - Writefor complete information and spt industrial, institutional. HISTORY When the closed type hot-water heating system was introduced, permitting operation at higher tempera tures, the expansion tank, usually installed in the base ment, replaced the open attic tank. Although superior to the open attic tank, the expan sion tank created several adverse operating conditions. For one, because of the solubility of air and water, the conventional expansion tank readily lost its air cushion. Thus the air gravitated to other parts of the system, causing improper heating, excessive venting, noise, and corrosion. Introduction of the Extrol unit, with its flexible butyl rubber barrier, prevents the loss of air. Furthermore, the barrier retains the air charge above atmospheric . pressure, so that water is held in position at high points in the line as system water is alternately heated and cooled. ' Until recent years, no suitable material was available for use as a diaphragm of this type--flexible, yet air tight. The Extrol Unit thus helps solve a number of problems formerly common to hot water heating systems. ^cations on Extrol unitsfor commercial, id residential applications F Heating Systems h* Trmfer DAVIS ENGINEERING CORPORATION ;1064 East Grand Street, Elizabeth 4, New Jersey I 30 Rockefeller Plaza, New York 20, New'York' 385 Paracoil fuel oil heaters for every application. : TANKSUCTION HEATERS^ . ' .. -To i(wot viscose^ftvldsjn bufkstordgf^fc tanks to transport tempefatures-ViSL^'iEk U-TUBE FUEL OIL HEATER*?' -; for sub-water fine-or. low pressure;^ v^*tom. 6-pass design for discharge sides?' or.fuel pump -- 2-pass design for^suction side.-4&. .: -.e lit HORIZONTAL TANK> SUCTION: HEATERS.^ For-obove-ground storage'tanks - AU service':. connections.are . outside the lank ;',in a ground-level^^, .access chamber? ^ ~ -VERTICAL TANK SUCTION HEATERS for below-ground' / storage tanks? FUEL' OIL' HEATER^g* .TUBULAR TYPE.*1*^ For high pressure steam^Maximum capacity with*mihifrium size-'.g^fe - r paraps obe ` ` oil LEAK - DETECTION SYSTEM Protecti'against oil'* . contamination by -1-" a '-!!;.-' ^continuously `checking^? srT'^t. purify of.condensate ^SS leaving steam-t^e?; ': : * fuel, oil beaten/*?; t ''.THERMO^liM"-SAFETY TYPE-FUEL OIL/HIATER ' . ' ` ^JDpubie tube elements (one jube inside another) V'TVlh heat transfer liquid-between tubes, J?j>cr0,t'plete)y isolote^fuel piFond water systems > .Minimum-size units delivef-fuli-rated heating ^-capacity: with' ho possibility ofiboiler water ^contamination, by* fuel oil.-t'i.r'; -for high-pressure STEAM 46s heating medium . v * . .. . :*  386 Heating Systems GENERAL FITTINGS COMPANY East Greenwich, Rhode Island, U. S. A. P. O. Box 151K HEAT EXCHANGERS GENERAL Converters Heating Systems Vim Hiiigi Rs4!a'!e, Oil 387 KILLEBREW Engineering'^'^^^^^^^*^Corporation 8640 Pardee Lane, Saint Louis 23, Mo. ASME FABRICATION Steam Converter GENERAL RC Converter ... shell and tube heat exchanger, two pass construction, steam in shell, water in tubes. U-bend copper tubing eliminates expansion strains. Removable tube bundle. Used ior forced circulation hot water beating systems. Alin for maintaining temperature in swimming pools. Capaci ties to 1800 gallons per minute flow. High Temperature Water Converter GENERAL BC Converters ... for high temperature hot water heating systems--high temperature, high pressure water circuit in tubes, medium temperature water circuit in shell. Number of in head varies from two to ten, depending upon de sign conditions and is combined with varying baffle pitch to give very high heat transfer efficiency. Design pressures tube side 400 psig and 660 prig. Inhibited admiralty tubing, semiconfined high pressure head gaskets, high temperature nozzles constructed with welding neck flanges. Design permits installa tion of temperature control bulb in shell for sensitive'response. Capacities to 1800 gpm flow medium temperature circuit. GENERAL Instantaneous Heaters FRE-FLO INSTANTANEOUS WATER HEATER Easily cleaned, straight tube with removable cover plate and floating head. Designed for heavy loads and fouling fluids. Standard sizes from 50 gph up. FRE-FLO STORAGE WATER HEATER Steel (rust resistant lining optional) or alloys. Copper tubes on square pitch or flat bundles to set low in tank for use as condensate cooler or used where heavy foul ing requires complete access for cleaning. . GENERAL ST Instantaneous Hot Water Heater . Steam Type GENERAL ST Instantaneous Hot Water Heater ... for hot water supply in hospitals, institutions, hotels and industrial plants. No storage necessary--heats water as fast as.it is drawn --should be sired to peak load requirements--can be used as a central hot water supply or as a spot source at point of use, such as a booster to provide sterilizing rinse 190 water for dish washing machines. Capacities to 300 gpm. GENERAL EV Steam Generator GENERAL BT Instantaneous Heater Boiler Water Type . GENERAL BT Instantaneous Heater ... Baffle construction for greater efficiency with boiler water circulated through the shell--circulator must be installed on boiler water circuit with control bulb in service water outlet. Affords accurate regula tion. Excellent hot water supply for apartment buildings. . GENERAL BO-Fnel Oil Preheater High Temperature Fluid Type GENERAL EV Steam Generator ... evaporator designed for service with high temperature water, Dowtherm, Aroclor or Heat Transfer Oil through the tubes--boiling water in lower half of shell, steam in upper half. Built-in steam separator, re movable tube bundle. Design presure to 660 psig. Design tem perature to 800F tube side. . Baffle Type GENERAL BO Fuel Oil Preheater ,.. Steam in tubes--oil in shell. Transverse baffles are designed to give outstanding tur bulence and heat transfer characteristics within conservative pressure drop limitations. For installation on discharge side of. pump. Cah'iSe used in conjunction with GENERAL Suction Oil Heater in tank. Capacities to 3800 gpm. - For fall write Heat Exchanger Divirion * FRE-FLO LOAD LEVELER A simple, nigged, packaged water heater designed specifically for handling extreme surge loads, yet levels the steam load on your boiler. Will deliver one or two temperatures of your selection, individually controlled. The Fre-Flo Load Leveler is completely assembled, ' ready to connect to utilities. Sizes from 450 gph and up. FRE-FLO RADIATION CONVERTER Complete range of sizes. Used with steam or boiler water. Cast iron head, steel shell, copper U tubes and f bronze tube supports or baffles. - WRITE US REGARDING YOUR HEAT EXCHANGE PROBLEMS FRE-FLO CATALOG AVAILABLE *388 Heating Systems b TroH pp^eu RICHMOND ENGINEERING CO., INC. 7th & Hospital Streets, Richmond, Va. RECO TANKS, INC. Holts Chapel Road--Greensboro, N. C. P.O. Box 147--Columbia, S. C. HEAT EXCHANGE EQUIPMENT The RECO price is competitive! Delivery is fast and sure. All RECO products are guaranteed. Because . RECO water heating plants handle maximum demand without straining, there will be a minimum of main tenance costs to add to your client's overhead. Specify RECO for your next heating job. For catalogs, write: Richmond Engineering Company, Inc., 7th & Hos pital Sts., Richmond, Virginia. CONVERTORS For forced circulation hot water heating systems specify RECO convertors. Live steam in a steel shell heats water in a copper tubing network. Removable heating elements are seamless U-bend tubes to elimi nate internal joints and expansion stresses. INSTANTANEOUS HEATERS Make it a RECO instantaneous heater when your steam supply is adequate for peak loads, and a con tinuous supply of hot water is needed. Live steam in a steel shell heats water or other liquids in. a multiple- pass network of copper tubing. STORAGE HEATERS Vertical and horizontal RECO storage heaters furnish large quantities of hot water for use at irregular inter vals. Removable heating elements of seamless copper U-bend tubes. Fabricated from steel, copper-silicon or stainless. Linings: Baked-on phenolic resin, galvanized, cement, copper or clad materials. - STORAGE TANKS RECO custom-builds storage tanks to your specifica tions. Bulk tanks, hydro-pneumatic tanks, above or underground tanks . . . ANY SIZE OR MATERIAL. All carry the famous RECO one-year guarantee of materials and workmanship. Underwriter's label for oil tanks or ASMS stamp for pressure tanks. CHECK THIS LIST OF 20 RECO HEATING & PLUMBING PRODUCTS Convertors * Hi Temp Hot Water Convertors Instantaneous Heaters Kitchen Booster Heaters Snow Melting Exchangers Feed Water Heaters Condensate Coolers Economizers Steam Gen erators Oil Tank Suction Heaters Fuel Oil Heat ers Pneumatic Tanks Surge Tanks Condensate Tanks Expansion and Compression Tanks Blow Off Tanks Swimming Pool Heaters Storage Heat ers Boiler Blow-Down Tanks Flash Tanks Heating Systems Sterling, Inc. 5208 West Clinton Avenue, Milwaukee 18, Wisconsin Heating and Temperature Control Equipment Distributed through leading Heating and Plumbing Wholesalers Sales Representatives in Principal Cities CONDENSATION PUMPS 4100-4200 Series A complete line of low pressure units for ratings up to 15,000 sq ft EDR at 20 psig. Four sizes assure accurate, easy selection of pump to boiler require ment. Steel or cast iron tanks. Centrifugal pumps, mechanical type seal, built-in Simplex or Duplex. Many modifications available to suit special applications. 3500 Series Heavy duty units built as condensation or boiler return systems. Pedestal mounted tanks. Horizontal pumps. Ratings up to 65,000 sq ft EDR, up to 150 lb psig. Available in standard units or built to specification. Special units for packaged boilers. 3700 Series Built with extra heavy cast iron tanks for underground returns and pit installations. Standard units from 2,000 to 20,000 sq ft EDR, 30 psig. Special units for larger ratings and higher pressures. SPECIAL UNITS We specialize in designing and building special equipment to solve difficult condensate and boiler return pumping problems. THERMOSTATIC TRAPS ' Exceptional for keeping radiation free of air and condensate. Uses the "Sterlco Vacuum Thermostat" which closes uniformly regardless of pres sure variation. If damaged, the thermostat fails in the closed position shutting off the radiation and giving positive indication that the trap needs attention. Trap maintenance greatly simplified. All traps equipped with replaceable seats. Three pressure ratings: 15, 65, 100 psig ^ in. L-P. angle body has smallest overall dimension for use on fin tube radiation. FLOAT AND THERMOSTATIC TRAPS Used wherever it is desired to prevent flow of steam, but to permit passage of air and water ... on unit heaters, large radiators and convectors, water heaters, steam main drips and other types of equipment where steam is used. Compact, rugged, easy to service. "Vacuum thermostat" vents air, float valve has plenty of capacity for large amounts of condensate. Sizes: % in., 1 in., 1J^ in., in., 2 in. Maximum pressures: 15,100 psig. 120-A THERMOTROLS Self-contained, thermostatically operated radiator valves for controlling individual room temperatures. For two pipe steam or hot water systems. A simple, relatively inexpensive system of control for new or old buildings. Especially good for remodeling old systems. ^ in., in., 1 in. sizes. Angle, straightway, corner body patterns. , 150-E SERIES TEMPERATURE CONTROL VALVE Self-powered, modulating, fully balanced control valve--applicable to any process involving heating or cooling by means of water, oil, steam, or other fluids. Bellows type stem seal and 125 psig makes it especially good for high temperature high pressure hot water systems. Single seated. Monel bellows: Armored capillary stainless steel seat, disc and stem. in., % in., 1 in. sizes. No. 117 Series Valves built in 1^ in. to 2 in. sizes for heating applications only. "Y" STRAINERS A complete line of "Y" Strainers. Brass strainers from % in. to 1 in. Cast iron from H in. to 3 in. 125 psig pressure rating. RADIATOR VALVES A complete line of Radiator Valves from hot water supply valves to heavy duty bellows seal type valves for Vacuum heating systems. Radiator Valves 389 "Y" Type Strainers  390 Henting System* . H. A. Thrush & Company Peru, Indiana FORCED CIRCULATING THRUSH FLOW CONTROL SYSTEM OF HOT WATER HEATING AND HEATING SPECIALTIES . Thrush Flow Control System of Radiant Hot Water Heating assures continuous radiant heat with practically no variation of room temperature, regardless of outdoor weather changes. It offers an ideal means of control for Lise with radiant panels, radiant baseboards, convectors or radiators. Circulation is forced and operation is entirely automatic. The Thrush Radiant He&t Control automatically compensates for outdoor weather changes. Provides an ample supply of hot water for kitchen, laundry and bath, both summer and winter. Wasteful, overheating is completely prevented. Piping plans and engineering asistance are available to the trade. Vertical Water Circulator Vertical Flow Valve with Air Tube THRUSH WATER CIRCULATORS Forced circulating pumps for Hot Water Heating and Domestic Water Systems. In sure uniform heating. Quiet and efficient, long lived and vibration-free. Sealed-in lubrication. Vertical and Horizontal are made in seven sices, 44 in., 1 in., 194 in., 194 in., 2 in., in. and 3 in. Hi-Head Vertical and Horizontal `Thrush Water Circulators, de signed for use with radiant haseboards, convectors, radiant panels, etc, which require higher heads, are also available in V* in, 1 in, 1V4 in. and 194 in. sizes. Thrush Water Circulators ore also available with Bronze body in 1 in. and 1)4 in. sizes, both hori zontal and vertical. Female threaded connections. THRUSH FLOW CONTROL VALVES Special check valves for use with automatically fired boilers, automatically control circulation when installed with a Thrush Circulator. Close tight when Circulator is not running, prevent gravity circulation when heat is not needed in the .radiators. This permits maintaining boiler water temperature high enough to heat domestic water, winter and summer, without overheating the building. Available with Air Tube which vests air freon boiler into pressure tank, greatly improving heatiog efficiency by elimi nating air from the system. 1 in. through 194 in. valves also available with solder type outlet unions.' Also made in angle type with or without air tube. Six sizes in Angle or Vertical types, 1 in, 114 in, 194 in, 2 in, 294 in. and 3 in. Horizontal Thrush Flow Control Valves, 1 in. through 2 in. sizes, are recommended for zoned systems and in stallations where head room makes it necessary to keep mains low. THRUSH AIR ELIMINATOR Thrush Air Eliminator Tank collects and removes air from water in the heating sys tem. Air in the water moves with circulation and will be trapped and released in the Eliminator preventing its interfering with circulation. Designed primarily for floor and ceiling panel systems, it can also be used with baseboards, convectors or radiators. Made in seven sizes, all with 1 in, lV* in. or 194 in. tappings. . THRUSH PRESSURE TANKS NOW HAVE VACUUM BREAKER. Thrush Pressure Tanks are made of heavy welded steel shells and heads and are guaranteed to be sir tight. Each Thrush Presure Tank comes equipped with a Thrush Vacuum Breaker at no extra.cost. Makes tank draining simple and quick. It is only necessary to close valve in Lank line, open drain and unscrew vacuum breaker. Thrush Pressure Tanks With Vacuum Breaker Automatic Fill ing Valve in., % in. and 1 in. No. 4 Relief Valve Yi in- and 1 in. THRUSH AUTOMATIC FILLING VALVES AND LOW PRESSURE RELIEF VALVES Whenever system pressure drops below setting of valve, city water pressure will be admitted by Thrush Automatic Pilling Valve until system pressure is restored. Presr sure setting is adjustable. Thrush Water Relief Valves protect heating boilers from exces pressures. Large diaphragm assures positive opening and doting. Convenient testing lever. Hd Water 391 H. A. Thrush & Company Peru, Indiana ASME RATED No. 46 THRUSH SAFETY RELIEF VALVE FOR HOT WATER HEATING SYSTEMS Rated output of 283,500 Btu based on steam capacity discharge. Primarily a water relief valve. Will also relieve steam should critically high temperatures occur. Testing lever. 30 lb pressure. 94 in. in let, 1 in. outlet. Same type available in settings to 125 lbs. DUAL CONTROL UNITS Thrush Dual Control Units provide auto matic filling and pressure relief for hot water heating systems. Proper water sup ply and working pressures in boiler maintained automatically. All have builtin strainers and check to prevent back flow from system. Low in cost, safe and dependable. Made in four types, all with brass working parte. Adjustable presure setting. Yi m, and 94 in. sizes. THRUSH WATER HEATERS Highly efficient heat exchangers or con verters. Provide Domestic Hot Water at low cost. Also used industrially for . heating or cooling liquids. Fourteen sizes, for Hot Water or Steam. Pressure up to 125 lb for water, SO lb for steam. Constructed with heavy cast iron shells and straight seamlera copper tubes. Both heads are removable for inspection of tubes and for easy cleaning. No. 75 Thrush High Pres- , sure Water Relief Valves To protect hot water beaters, range boilers azid automatic water heaters from excess pressure. Factory setting 85 lbs. Adjustable at factory to 150 lbs maxi mum. Other types available io 94 in, 94 in. and 1 in. sizes. No, 76 High Pressure and Temperature Relief Valves The valve illustrated above at right has an added safety feature. It not only guards against excessive pressures, but also relieves if excessive temperatures de velop A fusible element melts at 210 F. Other types available in Vi in. and 94 in. sizes. - Adjustable Supply Tees for One Pipe Systems Provide exact' balancing of forced circu lating one-pipe hot water beating systems. Available in bronze with solder connec tions for use with copper pipe and in threaded cast iron for steel pipe. Non- adjustable tees also available. ' No. 170M - 170F AUTOMATIC RESEATING TEMPERATURE AND PRESSURE RELIEF VALVES Thrush Twin-L Balancers Used to join two supply or two return branch mains into one common main. Handy lever permits balancing of circu lation in each circuit easily and quickly. Saves ten fittings commonly used to ac complish this. Available in cast iron or bronze -in three sizes. THRUSH MANIFOLDS AND BALANCING VALVES Thrush Manifolds save time, space and labor installing Radiant Heating. Avail able in 1 in. sad 194 in. sizes, each with two, three or four 94 in. or 94 in. threaded branch outlets. Also available in 194 in. and 1V4 in. sizes with three or five 94 in. solder branch connections.- Ends have solder connections. Manifold with Balancing Valves as shown above is used in return lines only. Used in supply lines without valves. Balancing Valves permit individual filling of each coil, eliminate air quickly and save time. Two types, three sizes, 44 in., 94 in. or 94 in. Flared coil fittings for 94 in. 94 in. tubing, 94 in. has solder connec tions. Where an Automatic Reseating Tem perature and Pressure Relief Valve is re quired by code, the No. 170M which has a male inlet or the No. 170F which has a female inlet will provide the Positive protection required. Reseats automati cally after each operation. Has con venient testing lever. 6 in. stem or short stemJ ASME rating 75 lbs, 450,000 Btu per hr; 100 lbs, 575000 Btu per hr; 125 lbs, 700,000 Btu per hr. AGA rating, 560,000 Btu per hr input. No* 5 Hot Water Air Valve An inexpensive, dependable, automatic air vent for Hot Water coils, convectors, radiators, unit heaters, and high points of mains. Tapping 94 in., IPT. No. 5 THRUSH TANK DRAIN Thrush Air Valve 12 in Box Combines Drain Valve and Vacuum Breaker in one handy, inexpensive fitting. Removing plug adxnite air to permit quick draining of waterlogged tank. ' . Thrush Tank Drain Write For New Condensed Catalog  392 Heating Systems bm v.u*. TACO HEATERS, INCORPORATED 1160 Cranston Street, Cranston 9, Rhode Island Corporate Office: 324 Madison Avenue, New York. In Canada: Taco Heaters of Canada, Ltd., 4 Gilead Place, Toronto 2 TACO LP PUMPS Serving the Hydronic Industry Since 1920 TACO MP PUMPS TACO WATER HEATERS, CONVERTERS, AND CHILLERS K lime adfi stage centrifugal pumps with: relatively few sites; many inter' changeable parts; broad range of per formance; high efficiencies. A base mountedline of pumps with the rugged dependability large installations require. Taco Converters and Water Heaters provide hot water and radiation for com mercial and inkiuitionat heating pur poses. Chillers are designed for chilling water in the air conditioning and re frigeration fields. - TACO CIRCULATOR Packed with quiet power and proven performance; sizes V* in. through 3 in. TACO 170 CENTRIFUGAL PUMP Excellent for cooling tower jobs; air- . conditioning installations... wherever a small top-quality built centrifugal pump is needed- . TACO VENTURI FITTINGS Powerful suction action draws water through radiator for positive circulation. May De used for above or below main radiation. Taco Super Venturis save you money by reducing branch sizes, copper tubing, pipe fittings and labor costs. TACO AIR-SCOOP Scoops air bubbles from hot water sys tem by a series of baffles. Air is then vented to either atmosphere or expan sion tank. When system is hist filled ... vent radiators and high points once ... do return to job! TACO PERFECTA Outstanding circulator; so quiet you won't believe it's running. TACO TEMPERING VALVE Guards against excessively hot do mestic hot water. Mixes cold water with hot water from Taco Tankless for storage beater to provide tempered water at fix- TACO FLOW REGULATOR tures. Limits water flow to specified require ments. TACO AUTOMATIC AIR VALVES TACO FLOW CHECK Easily installed in either angle or hori zontal position, the Taco Flow Check prevents hot water from entering the system when the thermostat stops the circulator. Taco-Vent for water systems is leakproofed. U has a porous plug that limits the flow of water through valve. The Steam Vent eliminates pinging, clicking or hissing. TACO RELIEF AND REDUCING VALVES TACO PANELTROL Adjustable to deliver water to radiant heating panels for any-temperature be tween 110F and 150F even though boiler water is kept at higher temperature for summer-winter hot water. Automatically mjniaiTi<i sufficient wa ter and pressure in system. The Taco ASMS Relief Valve handles 80 percent of all hot water heating jobs, ana is set to relieve at 29 lbs. Reducing Valve is factory set at 12 lbs. SEND FOB CATALOG CONTAINING COMPLETE INFORMATION AND ENGINEERING DATA Healing Systems . %Z,TSZ, _= YULA CORPORATION^" " (formerly) Yula Water Heaters Inc.--Established 1926. 330 Bryant Avenue, New York 59, New York Designers and Manufacturers of Heat Transfer Equipment - Member Fuel Oil and Water Heater Manufacturers Association 393 "YULATOM" FUEL OIL PROTECTION HEATER.'* Type "YA", approved by the Board of Standards and Appeals, City of New York-Cal. No. 678-57-S.A. Here is a truly low cost, light weight, easy to install below water line oil heater. Due to its counterflow operation the exit oil can be delivered at high temperatures. Should a leak occur it is impossible for oil to get into Boiler or Piping. Made by the designer of the famous "Yulatrol" Oil Heater, so you know it is good. OIL TANK SUCTION HEATER--used to lower the viscosity of oil in bulk storage tanks to facilitate pumping. Only oil being drawn off is heated making it unnecessary to heat entire tank. "U" TUBE CONVERTOR--used in hot water heating systems where steam is passed through the shell while circulated water passes through the tubes. "U"- Tube construction allows for expansion of the tubes due to great temperature variations. . FULL FLOATING HEAD EXCHANGER--used where straight tube construction is desirable affording easy access and cleaning of interior chambers while allowing for expansion of tube bundle. YULA THERMOSTATIC MIXING VALVE Automatically mixes hot and cold water and other DRY EXPANSION TYPE FREON COOLER The Yula Dry Expansion Freon Water Cooler is for use in air conditioning, refrigerating, industrial and fluids. Delivers mixture at any pre-determined con stant temperature. Sizes % in. through 3 in. Special calibrations are possible. process cooling, using water and other fluids. The , refrigerant passes through the tube side and is va porized. The fluid being cooled passes through the shell Special Features: Liquid expansion thermostat gives uniform power at all points of the range with positive, genUe throttling action. The disc controlling the porta side which is baffed. The carefully designed tube has two seats on a 35 deg angle; precluding freezing. arrangement in these coolers provides high thermal Seat is in one part. Castings are heavy bronze. Close efficiency and little pressure loss. Sound engineering temperature regulation is obtained because valve is has assured a positive oil return with the refrigerant in these units. Heat transfer and turbulent flow is as sured. extremely sensitive. Seat spring is made of durable, corrosion resistant stainless steeL Complete shut-off on hot and cold water port in "non-draw" periods. We manufacture all types of Heat Transfer Equipment for use ia many fields Agents in Principal Gtiee Buffalo Pumps Division of Buffalo Forge Co. 450 Broadway, Buffalo, N. Y. Canada Pumps, Ltd., Kitchener, Ont. A complete line of Centrifugal Pumps, Single and Double Suction, Single and Multistage, for all types of and air-conditioning installations. Write for Engineering Bulletins mentioned below, or consult tbe Buffalo Engineering Representative in any principal City. DOUBLE SUCTION SINGLE STAGE PUMPS Extensively used for handling chilled water and other air-conditioning and clear-water applications includ ing air washers, these pumps are available in capacities from 10 to 14,000 U.S. gallons per minute, against heads up to 350 ft. Highly efficient operation is pro vided by their simply formed water passages and their hydraulically balanced impellers (water enters each side of impeller with equal pressure and volume). All parts are ample for durability under bard service. Top half of the casing is readily removable for servicing without disturbing piping. Write for BULLETIN 955S. CLOSE-COUPLED SINGLE SUCTION PUMPS These pumps offer.the advantages of compactness, high performance and simple installation without need for shaft alignment. (A 4 in. pump, delivering 600 gpm at 60-ft nead, requires less than 2 cu ft of space.) Available in 1 in. to 6 in. discharge sizes. Design per mits vertical or horizontal installation, with discharge adjustable to desired angle. These pumps are suited to handling hot water with low submergence. Write for Bulletin 975B. . SINGLE SUCTION MULTISTAGE PUMPS sed for boiler-feed and other clear water service, these heavy-duty imps are especially suited to delivering at high pressures. and temperaires Available in two- and four-stage models for capacities from 20 to gpm at heads up to 1500 ft. Shaft is extra-heavy and oversize bearings ipport the shaft on each end. Top-half of pump casing is removable for :rvicing without disturbing piping. Write for BULLETIN 980E. XJTOMATIC SUMP PUMPS hese are shipped as preassembled units ready to put into the sump pit, ire and start pumping. No priming is necessary, since there is no suction ft. Thrust load is carried by ball bearings, and the shaft is fully enclosed > prevent fouling with waste or stringy matter from the sump. All parts re readily accessible. Write for BULLETIN 96SH. Healing Systems . Pup* DOMESTIC PUMP ^MANUFACTURING %395 C OR P. SHIPPINSSUlO nomcsTir MAKERS OR DIPINOAlti ^ COMMtKCtAl PUMPS SlMCt t903 PENNSYLVANIA Products: Return Line Vacuum Heating Pumps; Condensation Pumps; Boiler Feed Pumps; Condensate Accumulators; Vertical, Horizontal and Flange Mounted Centrifugal Pumps; Air Separators. FOUR COMPLETE LINES OF VACUUM HEATING PUMPS Type VLR and VL Single and Duplex Units for Standard and Special capacities thru 65,000 sq ft EDR ana up to 75 psi. Bulletins GS-llOA and GS-13I. Type VCA with individually sizea and separately controlled vacuum and con densate pumps. Air capacities thru 75 cfm and 20 in. Hg and condensate capaci ties thru 150 gpm at 75 psi. Bulletin GS-152. Type VCM custom designed for each application. Automatic make-up. Pum, individually sized and controlled for maximum flexibility and economy. Av: * ' with 1, 2 or 4 vacuum pumps, each rated up to 90 cfm and 20 in. Hg and 1 to 4 boiler feed pumps, each rated up to 400 gpm and thru 75 psi discharge pressure. Bulletin GS-152. The heart of all Domestic Vacuum Pumps is the multi-jet vacuum producer. Average air evacuating rate is twice its rating, reducing operating time and power cost Removes up to 300 per cent of rated air capacity at start of heating cycle to shorten warm-up period It is simple, efficient and capable of producing a near perfect vac uum. It will retain its original effectiveness year after year. CONDENSATION & BOILER FEED PUMPS Types SC and CC Single and Duplex units for systems thru 100,000 sq ft EDR and 60 psi. A compact dependable condensation pump with motor vertically mounted above floor dirt and water. Each motor is controlled by its own float switch. Low inlet receiver of lifetime cast iron. Bronze fitted centrifugal pumps for long life at peak efficiency. 1750 and 3500 RPM motors. Bulletins GS-202 and GS-221. -* Type CMS and CM units provide automatic water make-up to replace water lost from the system and to maintain the most efficient boiler steaming level for systems thru 200,000 sq ft EDR and 60 psi Single and Duplex units with receivers sized for ample conden sate storage. 1750 and 3500 RPM bronze fitted cen trifugal pumps designed to handle near boiling water. Bulletins GS-202 and GS-230. Type CU units for use where the return mains are below the floor or lower than the inlet of a horizontal condensation pump. The lifetime cast iron receiver is buried with the cover flush with the floor and with the motor and float switch extending above it. Bronze fitted centrifugal pumps have ball thrust bearings, stainless steel shafts and flexible couplings. Single and Duplex units for capacities thru 50,000 EDR and 75 psi, 1750 and 3500 RPM motors. Duplex units have automatic mechanical alternation and stand-by or double capacity in event of abnormal demand. Bulletin GS-240. Vacuum Pump Type VCA Type VCM CENTRIFUGAL PUMPS Horizontal, vertical and flange mounted pumps have same high quality that is built into all "Domestic" heating pumps. Heads to 230 ft, capacities to 450 gpm. Bulletin GS-691. Condensation Pump Type CC t, 396 Heating Systems Putting ideas to Work FOOD MACHINERY AND CHEMICAL CORPORATION CHICAGO PUMP COMPANY 622 DIVERSE? PARKWAY CHICAGO 14. ILLINOIS In Principal Cities Throughout The United States and Foreign Countries PRODUCTS Condomotion. House, Booster and Fire Pumps ... Return Line Vacuum Heating and Boiler Feed Pumps... Gradating, Brine, Sewage, Sump, Sludge Pumps... Pneumatic and Tankless Water Supply Systems . . . Sealed Electrode Rootless Pump Controller ... Automatic Alternator for Duplex Sets of Pumps HORIZONTALLY SPUT-CASE PUMPS For house, fire and booster service. Raggedly constructed, heavy duty, providing lasting, maintenance-free operation. The rotating assembly may be inspected withont disconnecting the piping. Capacities np to 1900 C.P.M.--beads to 530 ft. Ask for Bulletins 98 and 102. DUPLEX CONDO-VAC RETURN LINE VACUUM AND BOILER PEED PUMPS Specifically designed for vacuum heating systems. The water capacity of CONDO-VAC pumps remains constant up to the boiling point. The air capacity remains constant up to the evaporation point. Pressures up to 40 lbs. Capacities from 2500 to 150,000 EDR. Ask for Bulletin 270. Putting Ida a to Work FOOD MACHINERY AND CHEMICAL CORPORATION CHICAGO RUMP COMPANY 622 DIVERSE? PARKWAY . CHICAGO 1*. ILLINOIS In .Principal Cities Throughout The United States and Foreign Countries PRODUCTS Condensation, House, Booster and fire Pumps .,. Return Line Vacuum Heating and Boiler Feed Pumps .. . Gradating, Brine, Sewage, Sump, Sludge Pumps . .. Pneumatic and Tankless Water Supply Systems ... Sealed Electrode Bootless Pump Controller... Automatic Alternator for Duplex Sets of Pumps ' TYPE NYC VERTICAL CONDENSATION PUMP & RECEIVER Specifically designed for low re turn service and underground installations. Flanges are ac curately finished and gasketed to prevent steam leaks. Pump and receiver are shipped as a unit, ready to install. For 1000 to 40,000 EDR and 10 to 25 lbs. pressure- Ask for Bulletin 254-A. TYPE LGL2 AUTOMATIC ELECTRIC SUMP PUMP Specifically designed to drain basements, pits and sumps. Centrifugal volute pump with open bronze im* peller. A cast iron strainer of large area surrounds the suction opening. Ask for Bulletin 118-F-3. VERTICAL CLOSED SHAFT NON-CLOG PUMP Available in either single or duplex units . . . suitable for either sump or sewage serv ice. Pump is mounted on separate floor plate to allow easy removal for servicing. Ask for Bulletin 124-F. TYPE CC. CLOSE COUPLED BOOSTER PUMP Designed to handle the toughest pumping jobs efficiently and in the least possible space. May be mounted in any position as long as the motor is not lower than the pomp. Provided with leak-proof mechanical seal. Capacities up to 500 G.P.M.--heads to 21S ft. Ask for Bulletin 108. SURE RETURN CONDENSATION PUMP & RECEIVER For systems up to 75,000 EDR and for low and medium pres sures. Available in either single or duplex units. The base serves as a large capacity manifold throngh which the con densate flows by gravity from the receiver to the pump. SURE RETURN pumps never steam bind. Ask for Bulletin 250-F. TYPE PC PEDESTAL MOUNTED SIDE SUCTION PUMP Manufactured to the same exacting engineering standards as the Type CC Pump, and with the same capacities and heads. The flexible coupling drive permits easy field servicing . . . choice of motor manufacture. Ask for Bulletin 107. TYPE AVC CONDENSATION PUMP & RECEIVER Heavy cast iron receiver with low inlet for floor mounting or shallow pit. Sets on floor -- no foundation bolts necessary. Weight of unit and piping hold unit firmly in place. For 500 to 10,000 EDR and 10 to 30 lbs. pressure. Ask for Bulletin 24S-F. TYPE FC DUPLEX CONDENSATION UNIT Single or duplex units are specifically designed for operating conditions where pressures are high and eapacitiea relatively small. For duties up to 50,000 EDR and discharge pressures up lo 150 lbs. Ask for Bulletin 260-C. TYPE F FLUSH KLEEN CLOG-PROOF SEWAGE PUMP Only liquids are handled by the impeller. Solids and other coarse matter are retained is the strainer housing until clean , ly flushed to the sewer. Ask for Bulletins 122-C, 122-S. SEALED ELECTRODE FLOATLESS PUMP CONTROLLER . . . used exclusively with "Chicago" Sewage and Drainage Samp Pumps. The SEALTRODE*'Controller has every advantage of other floatless controllers,, plus these advantages of being sealed: Electrode* never become insulated and coated with grease, oil or soap. Beetrodes are never affected by cor rosive elements in sewage and drain age water. No moving parts in liquid. Low. original cost. . . eliminates need for duplex float switches and float guide pipes. Low maintenance cost. ' Ask for Bulletin 128  398 Heating Systems ? THE NASH ENGINEERING COMPANY 234 Wilson Road South Norwalk, Conn., U. S. A. Sales and Service Offices in all Principal Cities 399 THE NASH ENGINEERING COMPANY 234 Wilson Road South Norwalk, Conn., U. S. A. Sales and Service Offices in all Principal Cities RETURN LINE VACUUM HEATING PUMP TYPE CSM The new CSM Heating Pump achieves a high level of performance and efficiency. Complete flexibility is secured in this design, since each pumping element is driven by its own motor, actuated by its own control. This makes possible a wide range of air and water capacities that can be selected to meet the exact requirements of each particular job. ' These pumps are now available in a full range of air and water capacity combinations, for operation up to 20 inches Hg vacuum, and for pressures from 10 lb to 70 lbs. Bulletin on request. CONDENSATION PUMP TYPE CS Following the advanced design of our CSM Heating Pumps, the CS Condensation Pump has features representing long life, dependable operation and low maintenance and installation cost. Pump is single suction centrifugal in bronze fitted construction with renewable bronze sealing rings. Balanced impeller is designed for high efficiency handling hot condensate. Pump and motor form a compact unit. Simple mechanical seal replaces conventional stuffing box, eliminating maintenance. Strainer area nearly three times that in previous pumps. Easily removed for cleaning. Inlet connection is only 12, 14 or 15 inches, depending upon size of unit, permitting easy and low cost installation. Bulletin on request. RETURN LINE VACUUM HEATING PUMP TYPE CSI Now a Nash quality Vacuum Heating Pump can be economically installed and operated on any steam heating job. Engineered forhigh performance and low installed first cost, this new pump still makes use of time tested Nash prin ciples of operation. The Nash CSI has generous air capacity and features a wide choice of water capacities and discharge pressures. The right combination of capacities is at hand to match the requirements of the job. It is no longer necessary to pay extra for a pump with excessive water capacity, excessive discharge pressure, or in an attempt to get adequate air capacity. Capacities to 40,000 sq ft EDR. Bulletin on request. NASH HOSPITAL PUMPS For vacuum and pressure systems in hospitals to provide vacuum or pressure to operating rooms, laboratories and wards. Nash pumps possess particular characteristics adapting them to this exacting service. Silent service is assured, because the pumps and equipment are installed in a mechanical equipment room. Automatic control assures constant maintenance of the correct vacuum or pressure. No pulsation is present in either vacuum or pressure produced by Nash Pumps. Air delivered by Nash Compressors is entirely free from dust, heat or oil. Even dust entering the pump inlet is effectively removed. No oil or dust filters are required. No expert attendance is required. Bulletin on request.  400 INDUSTRIAL Heating Systems p*ni THe KRAISSL COMPANY DfCOSPO&AlED PUMPS--SEPARATORS--ENGINEERING EQUIPMENT Main Office and Factory Kraissl Building, 297 Williams Ave.f Hackensack, NJ. Sales Representatives in Principal Cities MARINE APPLICATION Class 25 small -size air pumps Bulletins A -1683-1679 We have concentrated for a period of over 30 years on the design, development, manufacture and supply of pumps, separators and fluid handling accessories to meet the requirements of original equipment manu facturers where our products.become an integral part 'of machines and installations. We do not believe any one design will meet all requirements, and our extended line reflects the wide variety of standardized equipment now available. If none of these items meet your, needs, Kraissl Engineers will be most happy to consider modifications or design for your application. Bulletins A-15S1-1401-18U Class SO roller pumps Bulletin A-1SS0 KRAISSL AIR PUMPS Rotary Compressors and Vacuum Pumps Single stage; vane and roller designs Capacities: Vi to 170 scfm Pressures: to 50 psig Vacuums: to28 in. Hg (except laboratory models to 29H in. Hg) . Patented force feed system of lubrication on oil lubricated models. Dry lubricated models aim available. Convection, fan, and water cooled models. . KRAISSL LIQUID PUMPS Gear, roller and centrifugal designs; direct and reduction drives for standard and high pressures. -. . Designed for applications in the fuel op , and hydraulic fields. Class 60 fuel oil pumps are l/L-listed in most commonly usedsizes. Capacities: to 210 gpm Pressures: to 400 psig KRAISSL SEPARATORS Filters and strainers in single and duplex models for liquids and steam- Listed by Underwriter's Laboratories in most com monly used sizes. Sizes: K in. to 6 in. std., single special to 12 in. ^,, Body materials: C.I., C.S., Bronze, S. S. Basset materials: Brass, Steel, Monel, Class 60 direct drive pumps Bulletin A-1904 . special 1200 psi. Write far General Bulletin A-1803 which summarizes our line and indexes available literature or specific bulletins describing products, of your interest. In addition to the products indicated, we currently manufacture a line of special TRANSFER VALVES, small capacity CENTRIFUGAL PUMPS, and AIR FILTERS. Class 72 single separators Bulletins A-1735-188S Bulletin A-1889 Class 72 integral duplex separators Bulletins A-1430-1698 Class 60 M motorized pumps Bulletin A-1K7 Class 72-A 3-piece duplex sep arators Bulletins A-18t4'l4^ USI-1876 Heating Systems 401 PEERLESS PUMP DIVISION Food Machinery and Chemical Corporation PLANTS: Los Angeles 31, Calif. Indianapolis 8, Ind. 1 3Q1 West Avenue 26 2005 Northwestern Avenue Offices: New York; Atlanta; Indianapolis; Chicago; St. Louis; Dallas* Plainview, Lubbock, Texas; Albuquerque, New Mexico; Phoenix, Arizona; Fresno, Los Angeles, Calif. Products: . Vertical Pumps: Deep and shallow well pumps; water supply, boosting, circulating and waste disposal pumps; condensate pumps; sump pumps. All types of drive. Horizontal Pumps: General purpose horizontal split case and end-suction pumps; turbine vane type pumps; boiler feed pumps; condensate pumps; circulating pumps; process pumps. All types of drive. Peerless Type PE integral HP general purpose end-suction close-coupled pump ' Peerless Type AquaLine general purpose horizontal centrifugal split case pump HP range: 1 to 4) HP. Capacities: 30 to 800 gpm. Heads: up to 260 ft. Design: single-stage, end - suction. Drives: standard horizontal NEMA mo tor. Screwed and flanged connections. Bronze impeller. Compact, versatile, dependable and efficient. Good hydraulic characteristics. Extremely durable and economical to operate. Completely described in Bulletin B-SS00. Peerless Type PE-A fractional HE general purpose end-suc tion close-coupled pump For hot and cold water handling, circu lation and boosting. Discharge sizes: 1)4 in. to 8 in. Capacities: up to 2600 gpm. Heads.: up to 350 ft. Temperature range: up to 250F. Drives: motor. The AquaLine volute is cast iron, bronze fitted, impeller is cast bronze. Available with packing gland or replaceable me chanical shaft seals. Highly dependable and economical to operate. Fully de scribed in Bulletin B-tl00. Peerless Type A general purpose horizontal centrifugal split case pump Peerless deep well pump For water supply services. Capacities: 15 to 30,000 gpm for installations in 4 in. wells or larger, to any practical depth. Adaptable to motor, belt, gear or steam drives. This turbine pump fea tures several design advantages special with Peerless; tne cooling method, unique bearing contact, and packing arrangements are examples. Available ' in water or oil lubricated line-shaft types. Described in Bulletin B-W. Peerless Vertical Pump Very good for adaptation to liquid mov ing equipment or systems, iff range: Vi to HP at 3450 rpm. Capacity: 10 to 65 gpm. Heads: up to 110 ft. De sign: single-stage, close-coupled, end- suction. Drives: ball bearing motor with stainless steel shaft. Castiron volute, east bronze impeller. Designed for installation at any angle; compact, flexible. Completely described in Bulletin B-9SO0. For the widest variety of pumping serv ices. Capacities: to 70,000 gpm. Heads: to 300 ft. Single stage, split case design. Drives: direct-connected electric motor; belted drives; diesel, natural gas, and asoline engine; steam turbine; comillation drives. Double-suction sizes 1)4 in. through 48 in., bottom suction sizes, 12 in. through 42 in. Completely' described in Bulletin B-1800. Other comprehensive, illustrated bulletins describing Peerless' complete line of vertical and horizontal pumps for all types of domestic, industrial and commercial service are immediately available. Request copies describing the type pump in which you are interested to the factory, address shown above. For application to cooling tower service, tank pumping, line pumping, boosting and recirculation. Capacities: 30 to 40,000 gpm. Heads: to 1000 ft. Hp range: electric, up to 2500 bp; right angle gear drives, up to 300 hp; steam turbine, as required. Pump column sizes: 2)4 in to 30 in. inclusive. Liquid temperatare range: to250 F. Available in water lubricated open line-shaft construction and enclosed line-shaft oil lubrication types. Described in Bulletin B-605. Peerless Hydro-Line encased, close-coupled vertical centrifugal pump Especially- suited to pumping hydro carbons such as gasoline, butane, pro pane, hot oils, etc.; hot or cold water; mild acids, basic and salt solutions. Capacities: up to 3000 gpm. Heads: to 1000 ft. Temperatures: up to 400F. Drives: as required, standard vertical solid shaft or explosion-proof motors, steam turbines. Request Bulletin 8-1700.  402 Heating System: SKIDMORE CORPORATION ST. JOSEPH, MICHIGAN Quality Heating Pumps Since 1921 SKIDMORE TYPE UV PUMP The Skidmore Type UV Condensation Pump, single or duplex unit, is designed for use where returns are too low to permit the operation of horizontal type pumps. Type UV Pump operates very satisfactorily where condensate is to be returned to the boiler or other points, from all types of steam heating systems or process equipment. Type UV Pump consists of vertical pump and motor unit with float and float switch mech anism mounted on cover plate which i9 bolted to sump type receiver. Capacities 2000 to 40,000 sq ft EDR and discharge pressures from 10 to 75 lb. SKIDMORE TYPE CCVS PUMP The Skidmore Type CCVS Condensate Pump is new close-coupled design. Built to give maximum efficiency, yet requires a minimum of space. Shown above is the duplex pump with two float switches. This model is also furnished with automatic alternator. The CCVS Pump is also built in single unit. Motor and pump are bolted to receiver. Pump is bronze fitted throughout with enclosed centrifugal impeller of special design for hot water. Capacities 500 to 10,000 sq ft EDR and pressures from 10 to 40 lb. SKIDMORE TYPE HS PUMP The model HS Condensation pump is economically de signed to offer manmum efficiency with lower operat ing cost. The Type HS will operate at high tempera ture encountered in condensation pump service. The pump can be disassembled without disturbing piping connections. Furnished in either single or duplex type. Pump casing is constructed of heavy close grain cast iron, vertically split, bronze fitted throughout. Capaci ties 1,000 to 125,000 sq ft EDR, pressures 10 to 75 lb. SKIDMORE TYPE TM PUMP Type TM pump consists of motor, steel receiver, auto matic make-up valve mounted on receiver, water level gage, glass mounted on receiver, self-cleaning strainer between pump and receiver, assembled and mounted on steel base. Cast iron base furnished if required. Elec tric boiler water level controller furnished for mount ing on boiler. The Type TM Condensate and makeup water pump is of turbine type designed for boilers up to 250 hp and pressures up to 150 lb. Skidmore Pumps 'are built in single and duplex units SKI C O R P O RMTfli ST. HQSEEHMMlGRi Write for complete engineering data on all Skidmore Pumps Heuting Systems pp TUTHILL PUMP COMPANY 979 East 95th Street, Chicago 19, Illinois Representatives in all principal cities Pumps for Your Purpose 403 Tuthill manufactures a complete line of positive displacement rotary pumps for transfer oil burner, lubrication, and other services. Capacities from jHs to 200 gpm, for pressures to 500 psi, speeds to 3600 rpm. Also, pump units and special models for built-in applications.. Write for catalog describing complete line. SU Belt-Driven Pump Unit. For handling heavy fuel oil in commercial oil burner applications or with packaged boilers. Internal-gear pump design and 2 to 4 "V" belt drive insure quiet operation. Economically priced, it includes quality con struction features sueh as two ball-bearing pillow blocks, one point take-up which simplifies adjustment of belt tension and special fabricated steel base with versatile motor mounting. SU pump units are compact--can be provided with overall dimensions of only 14&4 in. x 25)4 in. Furnished with a wide variety of pump and motor combinations, for pressures up to 300 psi, capacities to 2030 gallons per hour. Sub-assemblies of pump, stub shaft, pillow blocks and sub-base can be provided for incorporation into larger equipment. Ask for Catalog 107. Model L--Small Industrial Pumps. Underwriters' Laboratory approved heavy oil pump series widely used for oil burner service, lubrication, liquid transfer and gen eral industrial use. Model L is a compact, highly efficient,, positive displacement, internal-gear rotary pump with mechanical-seal. It is provided for capacities from 20 to 360 gallons per hour at pressures up to 600 psi. Available with a variety of flange or foot mountings. Model L is directional in rotation and designed for direct drive at standard motor speeds. Ask for Catalog 101. Model R--Automatic Reversing Pumps. Model R incorporates the Tuthill auto matic reversing feature--designed to maintain constant direction of flow from the same port regardless of the direction of rotation of the driving shaft, without the use of check valves. Available in 11 sixes ranging in capacities from )4 to 200 gpm, for pressures up to 400 psi. Variations of models are available with mechanical shaft seal, internal-relieving feature and various mountings. Write for Catalog 106. Stripped Pumps for.Built-in Applications. For incorporation into products of manufacturers, Tuthill pumps can be furnished with the mounting bracket removed (Series S), or with mounting bracket and housing removed--providing pumping ele ments only (Series SA). Stripped pump units arc furnished in 10 sixes in capacities from to 200 gpm for pressures up to 200 psi. The series includes nonreversing and automatic reversing type pumps as well as units with automatic internal-relieving feature. Ask for Catalog 106. Cartridge-Type Lubrication Units. These compact, cartridge-type lubrication units are provided in 4 different models, each in 3 sixes, with a capacity range of from 55 to 170 gallons per hour, for pressures up to 200 psL They may be furnished for non-directional service or with the automatic reversing feature where the pomp must be driven by a reversing shaft. Choice of internal or external porting. Designed for flange mounting. Ask for Catalog 108. Integral Motor--Pump Units. Tuthill provides a complete range of close coupled pump and motor combinations for use where space and weight are primary con siderations. Units such as illustrated can normally reduce space required for pump and motor by at least six inches and cut weight by several pounds. Capacities range from 20 to 300 gph. Pumps are available for pressures to 500 psi. Larger pump and motor combinations can be provided with capacities to 50 gpm, for pressures to 400 psi. For original equipment applications involving substantial quantities Tuthill can develop a special POWERMITE combination where pump and motor are incor porated into one unit which takes up no more space than a standard electric motor (a typical POWERMITE measures only 3Ji in. x 7M in ). Water Pumps. Tuthill provides vaae-type water pumps for capacities up to 75 gph` ' at.pressures up to 150 psi. These are particularly adapted for applications involving boiler make-up water, or other boiler feed applications. Catalog No. }00 Describing Complete Tuthill. Line Also Available on Request.  404 The Y. D. Anderson Company Division of International Basic Economy Corp. I960 West 96th Street, Cleveland 2, Ohio Beating Systems Representatives and jobbers in all principal cities Quality Steam Specialties Since 1886 FOUR TYPES OF STEAM TRAPS A Trap for every purpose Super -Silvertop Heat-Kwik : Quik-Flex Thermostatic Inverted Bucket Combination SUPER-SILVER TOP Inverted Bucket Steam Traps Anderson Float Application--The inverted backet trap is recognized as the best trap for most inside installations, as it is actuated by a liquid or gas rather than temperature. Available standard or with air elimina tor (sometimes called blast type trap) where it is necessary to remove air quickly. Description--Hooks up as an elbow or straight-in-line--only one nipple needed. Head and body of cast semi-steel; valve and seat of Anderloy; stainless steel mechanism and copper bucket (stainless steel buckets available). Precision Parts Alignment--The bucket does not swing free. It is guided on a hexagonal tube. Keeps all parts in proper alignment and prevents bucket damage. Positive closing of the valve is insured. SPECIFICATIONS Sise No. Trap......... Sise Coanaetuoa___ (Bee Note) May Ga. Pressure... list Price................. WITH THERMAL AIR ELIMINATOR ..I $11.60 I 310-60 I $11.80 I 313.60 I 317.60 $28.30 I TO.tOI 352.80 | 388.40 CAPACITY IN POUNDS OF WATER PER HOUR HEAT-KWIK Combination 9500 8500 7800 13500 14000 11500 11500 'CtMdtlcitaMdeD continuous Uow. When ordering be sore to specify maximum steam pro cure. Note: Pipe sixes (howu to heavy type are standard and traps will be shipped tapped standard unless otherwise specified- Pipe sixes shown In light type furnished at no additional cost but only from Cleveland stock. ______________________Write for Bulletin 637. Application--For fast air and conden Description--Traps have separate ori sate elimination, even at extremely low fices, one for condensate and a separate bellows orifice for air. Bead and body of pressures. This feature is an advantage cast semi-steel; valve and seat of Ander- in systems requiring fast heat such as kettles, autoclaves, dryers, cookers, loy; stainless steel mechanism; copper bucket; brente bellows for BL series for 50 lb service and monel bellows for BH etc.___________________ Write tor Bulletin 28. series for 150 lb service._____________ SPECIFICATIONS QUIK-FLEX Thermostatic STEAM TRAPS Application--Designed primarily for outdoor installation where a freezeproof trap is required; such .as tracer lines, meter boxes, drips, etc., found iu chem ical. refinery, solvent and other indus trial plants. Air and condensate is auto matically discharged. Description--A bellows actuated trap for fast air removal and condensate drainage for pressures up to 250 lb. Furnished with either bronze or monel bellows. Body and head of brass and cast semi-steel (see below) Valve and seat of Anderloy, a tough chrome nickel alloy. Guaranteed against freezing. SPECIFICATIONS Sixe Nember of Trap.......... Sise Pipe Connections........ Maximum Gauge Prenure... Body Material...................... List Price (Monel Bellows). List Price (Bronte Bellowa). S3? 01.00 B-2 Semi-Steel I Semi-Steel $4U8.0M0 1I*. ,1.$48.0M0 Differential Pressure 10 CAPACITIES IN POUNDS OF CONDENSATE PER HOUR 5.300 11,400 15.300 15.000 13.000 18,600 11,000 36,000 Write for Bulletin 157 Write for our 36-page engineering catalog "How To Select Steam Traps ' Speeielliei The Y. D. Anderson Company Division of International Basic Economy Corp. 1960 West 96th Street, Cleveland 2, Ohio 405 Representatives and jobbers in all principal cities Quality Steam Specialties Since 1886 Application--Use in steam lines or sys terns where traps must discharge con tinuously. (Inverted bucket traps dis charge intermittently.) Use to drain ANDERSON AIR RELEASE VALVES ANDERSONAIR RELEASE VALVE DOWN FEED -- RISER RETURN RISER-- Application--Anderson* Self-Cleaning Strainers remove scale, grit and sedi ment from the line ahead of steam traps, reducing valves, air tools, pumps, etc. SPECIFICATIONS Sise Number of Tnp.................................. Sis* Pipe Connections............................... Maximum Gauge Pleasure........ ....... list Fries (standard!................................. (stainle** steel Seat)............................... (with cage flass)..................................... 31 $50 $17.00 $22-00 87 yi'-Vi' 250 $03.00 75.00 S3 i'-m- 350 $ 91.00 105.00 84 1)4*.S' 350 $170.00 185.00 moisture and entrainment from air and gas pipelines, purifiers, separators and gas equipment. Description--Anderson Float Traps are Differ ential CAPACITY IN POUNDS OF WATER PER HOUR continuous flow type desirable for draining moisture from air or gas equip ment and ahead of condensate meters where intermittently discharging traps cannot be used. Traps are of rugged con 20 2200 4400 * 18000 3850 11000 4100 150 1000 3100 7800 900 1900 S8S0 13600 struction for heavy duty service. The head and body are cast semi-steel, float Write for Bulletin SI. stainless steel and working parts bronze and stainless steel. Application--Designed to eliminate air and gases from pipelines in applica tions such as domestic hot and cold water systems, hot water heating sys tems, chilled water coolers, air condi tioning systems, filters and any individ ual pipe-line or equipment carrying liquid. Description--Anderson Air Release Valves are automatic and release air from the lines as fast as it accumulatesThey are built to withstand pressures up to 500 lbs. Install at the highest point in all your liquid systems. Sim Number of Vrive................... 70 72 73 13 Sise Pipe Connection* (inlet)......... Vi' H' or 1'-1M' H" or 8ixe Pipe Conocotioes (outlet)....... fWum List Pries................ WW 150 ISO $13.00 $22.00 $48.00 Vi'or H* 390.00 Operating Pressure CAPACITY-CU- FT. FREE AIR PER MINUTE 10 7.0 20.6 9.3 23.5 $0.0 150 14.7 33.8 350 38.0 400 500 Write for Bulletin SS4. 53.0 90.0 89.0 34 38 * Typo LC Small Line Purifiers Type LC-50 LC-75 LC100 ve ils LC150 LC200 TypeL*IS>. *360 & 800 PSICLarg* Line PurtfiSe- Type L250 L-3 L-4 L-J L-6 L-8 L-10 Sixe Diameter Vi 2M H 2M l 3M m 3H IVi 5 3 5 Length 9 9 15 15 17 17 8 SVent Sise M M 44 Drain Sise H Vi H 44 # Sise 3 4 Diameter... Ih 8% 8W tim S3 16 30 14 33 35 80 35 Vent 8ise Drain Site 1 1H 1M 3 1 3 3)4 Alt above dimensions In Indie*. Bold face figure* for 801 PSIC Line Purifiers. Write for Bulletin 561 for rises ft in. through 3 In. Bulletin 2*1 for rise* 2H In. and larger. * Available from stock. Application--On steam lines and in boilers for clean, dry steam. Type L ahead of steam engines and turbines pro tect against slugs, line scale, moisture, salts and dirt. Type LC ahead of smaller steam air equipment such as heat ex changers, dryers, drums, etc. Internal type in boilers to deliver clean dry steam. For cleaning and drying air and other gases. Description--Type L * (flanged) for sizes 2H in. and larger. Type LC (threaded) for sizes K in- through 2 in. Units are installed as a compact unit in pipeline adjacent to the equipment theyy' protect- Low and high pressure types available, many from stock. Drained automatically by Float Trap (air or gas) or Inverted Bucket Trap (steam). SPECIFICATIONS AND PRICES Pipe Sixe.................................................... Overall Length............................... ....... Blowdown Connection Pine Size__ ___ Shipping Weight (Vbs.).......................... H' 3M' l44' & W i w V m 3V4 & s1yMv $44 m* O' S' 744' iyv 844' 3' 10* $4.00 $5.00 $7.35 $11.00 138.00 $30.00 List Price.............................. .................... (Bran Screen) 132.00 137.00 Writ* for Bulletin 253. Description--Stainless steel screens, (brass available on 2)4 in. and 3 in.) standard equipment, have extremely large free area. Screen for steam and gases has H* in. openings--for liquids Ms in- openings. Other sizes furnished when specified, prices on application. and Other Fluid Specialties"  406 Heating System* a*di*u>n Dunham-Bush, Inc. West Hartford 10 * Connecticut * U.S.A. RIVERSIDE. CALIFORNIA MICHIGAN CITY, INDIANA MARSHALLTOWN, IOWA BREWSTER. NEW YORK TORONTO 15, ONTARIO PORT HOPE, ONTARIO LONDON S.W. 19, ENGLAND SALES OFFICES WEST HABTFOBD. CONN. NEW fOBK. N. T. CHICAGO. ILLINOIS . RIVERSIDE, CALIFORNIA MICHjtCAJ! CITY,.INDIANA 17* Sooth Stroet 160 East 4M SL MSI N. Ltacots Are. 1S50 UimmIimUi Are. *( E. Second SC . MARSHALLTOWN, IOWA MINNEAPOLIS, MINN. ST. LOUIS 17, MO. WASHINGTON, D. C. 811 DECATOB, GEORGIA 116 Church SC JENKINTOWN, PENN. _ .SOI York Rood B. Main Si 2*4* Lrvdtie Are. Seath 2211 Bnatwood Bird.___ ^ HOUSTON, TEXAS LOS ANGELA. CALIF. *'I1l1l laIndd-iitaansaAAr.re, 2*16 Soeth Shepherd Drtre _____ 2# Cnril Sc (3NC3NNATI, OHIO CLEVELAND, OHIO TORONTO. CANADA 2722 Lord] Are. 22442 Lorain Beed Danham-Beeh (Cfcweda) Lid. N. W.___ DETROIT 21 MICH. 1(221 Wrecoin* Are. LONDON ENGLAND Ltd. Branaer Cerp. (Canada) Ltd. 140 WeadeU Are. Leaden, S. W. I*. England EXPORT DEPT: 179 SOUTH STREET, WEST HARTFORD, CONN. CHapel 9*8671 CABLE: BUSHEATX AIR CONDITIONING, REFRIGERATION, HEATING PRODUCTS AND ACCESSORIES CONVECTORS--Attractive, easy-to-install. Use with hot water or steam. Eight models, capacities with steam 1 lb entering air 65F: 9 to 139 EDR. Dimen sions: 4, 6, 8 and 10 in. wide; 18 to 112 in. long; 12 in. window convector, 20, 24, 26, 32, and 38 in. high. Picture window, extra long, plaster front and institu tional types also available. ' TYPE BFOT--High output baseboard with "snap in" features for even greater ease of assembly. Same diamper choice and heating element selection as BE-10. All accessories tailored to close tolerances enhancing beauty and simplifying installation. BE-10 BASEBOARD--Snap-on front baseboard for forced hot water, steam or vapor heating. Fits flush with floor. 10 in. high. Shipped in 2-ft to 10-ft lengths for easy, on-the-job cutting. Steel or copper elements shipped in 1- to 6-ft lengths. Semi-recessed and flushback enclosures. 12 in. baseboard also available for commercial applications. FIN-VECTOR*--Can be installed at any level above 4 in. from floor. Three style covers: sloping top, flat top, expanded metal. Adjustable hook-and-link hanger or new ball bearing bracket supports elements. One, two, or three tiers high. Two tube sizes, 1V4 in. and 2 in. steel or VA in. copper tube. Self-spacing fins. THERMO VECTOR* RADIATION--For along-thewall heating of educational, commercial' or institu tional buildings with steam or hot water. Flush-type model, one, two or three tiers high. Two tube sizes: 154 in- and 2 in. Lever- or knob-operated damper. ). . . Fwup, Air C*a4hiofttB| Durzh^zm-Bush, Inc. Vertical Unit Heater Multi-Zone Unit 407 HEATTNG-COOUNG UNITS--For individual cool ing with chilled water or heating with hot water; for individual cooling with direct expansion or heating with steam; cooling and ventilating; or heating and ventilating. Four sizes of vertical floor mounting type. Five sizes of horizontal ceiling mounted type. Can be exposed or recessed. UNIT HEATERS--Type M, Model H and HM, not shown. Cabinet type. Seven styles, 3 sizes. Blower fans directly mounted on double end shaft motor. Capacities at 2 lb steam, 60 F ent. air: 18,000 to 108,000 Btu. UNIT HEATERS---Type H. Horizontal discharge. 11 sizes, 2 models. Capacities at 2 lb steam, 60 F ent. air: 18,600 to 286,800 Btu per hour. UNIT HEATERS--Type C. Vertical discharge. Four types of diffusers available. Ten sizes, 2 models. Ca pacities at 2 lb steam, 60 F ent. air: 46,400 to 598,000 Btu. MULTI-ZONE UNITS are available in 9 sizes from 2560 to 28,800 cfm. They provide for simultaneous air conditioning of separate rooms or zones at desired tem peratures. They make possible individualized condi tioning of such areas with a single unit instead of several units. VACUUM PUMPS--Pull and maintain, at low am perage, up to 26 in. vacuum without dependence on close clearances. Only ONE principal moving part. Single motor easily handles BOTH air and condensate removal. Low 914-in. return line connections. Capac ities: 2,500 to 65,000 EDR. Single or duplex units. CENTRIFUGAL PUMPS--Volute type for horizontal or vertical installation. Thirteen sizes ranging from Vs bp to 2 hp, capacities to 150 gpm. Typical supply system applications include boiler feed, processing, drainage, washer service and booster service. Also used as circulators in evaporative condensers, cooling towers, hot water and chilled water systems etc. For applications involving fluids other than water (glycols, brines, light oils) consult factory for recommendation. CONDENSATION PUMPS----Pumps feature mechan ical seal that eliminates stuffing box worries. Ca pacities: 2,000 to 50,000 EDR. Single and duplex imit-w S Model C2 Vacuum Pump AS Centrifugal Pump Type CHV Condensation Pump 1  408 DunhamJIusk, Inc. Heating Systems sun bmii Sp*ciabfe No. IE Radiator Trap RADIATOR TRAPS--For all types of low pressure steam heating systems. Body and cover of cast bronze, disc of non-corrosive metal. Available in 6 patterns. Capacities from 200 to 700 EDR. Type TH1-A Thermostatic Trap THERMOSTATIC TRAPS--Trap has cast brass body and cover; replaceable stainless steel valve and seat; disc of non-corrosive metal. For 5 to 100 lb working pressures. Capacities from 125 to 4,500 lb of condensate per hour. FLOAT AND THERMOSTATIC TRAPS--Use as drip trap for steam mains, unit heaters, heat ex changers. Float, copper; float valve and seat, Monel metal. Up to 25 psi gauge working pressure. Sizes: 54, 1, 1 Vi, 1 Vi and 2 in. with capacities from 100 to 5,750 lb of condensate per hour.' Types OB and OBS Backet Traps INVERTED BUCKET TRAP--Body and cover of high tensile iron castings. Valve and seat (renewable and interchangeable) are specially hardened, corrosionresistant steel. Operating pressures 20 to 150 lb gauge. Sizes Vxy 54, 1 and 1V4 in. Capacities from 220 to 5,600 lb of condensate per hour. SPRING PACKED VALVES--For low-pressure sys. terns up to 25 lb. Heavy coil spring keeps packing tight around valve stem. Body and bonnet, cast brass. Sizes: 54 to 2 in. in 4 body patterns. *> . PACKLESS VALVES--Packless construction (no packing spring or stuffing box) provides tight perma nent seal. Sizes Yt to 1J4 in. in 4 body patterns. HOT WATER VALVES---For hot water heating systems with pressure to 125 lb. Cast brass body. Packing nut, one-piece asbestos ring provides tight stem Beal: Sizes 54 to 2 in. No. 400 Radiator Valve No. 600 Radiator Valve PACKED STEM VALVES--For low-pressure steam systems and hot water systems up to 125 lb. Cast brass body and bonnet. Sizes: Vi to 2 in. DUNHAM-BUSH HEATING SYSTEMS VARI-VAC DIFFERENTIAL VARI-VAC HEATING saves up to 40 per cent on fuel, because VARI-VAC automatically provides the exact amount of heat needed by using a continuous flow of sub-atmospheric steam at temperatures that vary with the weather. METRO9 single-riser method of piping, costs less to install and main tain. Provides continuous path for flow of steam from top to bottom of building. Continuous pipe runs down through overlying rooms and is offset into each room into convectors or baseboard radiation. Ht Watr Spccfelifa* Dunham-Bush, IflC. 409 DUNHAM-BUSH CIRCULATORS--Standard and high head capacity models for all water heating or cooling systems. Single spring motor coupling. Special brand name motor with built-in overload protection. Extra-large oil reservoir. Field replaceable seals. FLOW CONTROL VALVES--Completely automatic. No adjustment for winter-summer operation. Easy to clean without breaking pipe connections or removing valve mechanism. Universal pattern: 1 through 154 in. incl. Horizontal patterns: 2 to 3 in. incl. AIR SEPARATORS--Automatically remove air from forced hot water heating system. One-piece construc tion. Positively prevents re-entry of air into system. 30 psi working pressure. Sizes: SA to 214 in. incl. FLOW DIVERTOR FITTINGS--Assure proper water flow through all radiation. Only one fitting normally needed (on return) for each unit of radiation. Size (thread to thread): 1 in. x *4 in. to 2 in. x 1 in. inch; (sweat to sweat): 54 in. x 14 in. to 1 in. x 54 in. inch RELIEF AND REDUCING VALVES--Pressure Re lief Valves have extra-large diaphragm area, non stick design. Factory set at 30 lb. Pressure Reducing Valves have built-in strainer. Factory set 12 lb. Ad justable. Combination Relief and Reducing Valves available. CIRCULATOR VALVES--Pat. 2,817,489. Extralarge flow area reduces water resistance and circulator load. T-type handle operates in only Vs turn. Straight way and angle patterns; thread or sweat; full range of sizes; 125 psi working pressure. BALANCING ELBOWS AND FITTINGS--Extralarge flow area. Unique sloping seat provides V-shaped opening for accurate balancing from full open to any degree of closure. Thread or sweat. Complete line in cludes vent tees, union elbows, connectors. AUTOMATIC AIR VENTS--Expansion Type Vents need no adjustment. Manual venting for rapid air removal when system is first filled. 50 lb working pres sure. Float Type Vent has built-in siphon to prevent water-logging. 35 lb working pressure. VARI-FLOW CONTROLS--Fully automatic in door-outdoor temperature controls for all types of hot water heating systems. No seasonal adjustment needed. Immersion bulb and capillary "wrap-around" types. DISTRIBUTOR HEADS---For radiant pane! and "spaghetti" type hot water heating. Same 154 in. copper head usable for supply or return, both Yt and Vi in. tube connections. Each length has 14 pairs of connections. DUNHAM-BUSH, Inc., manufactures a complete line of air conditioning, refrigeration, heating products and accessories. For catalogs and literature write: Dept. HVAC-59, Dunham-Bush, Inc., West Hartford 10, Conn., or see your local Dunham-Bush Sales Engineer.  410 Heating System* HOFFMAN SPECIALTY MFG. CORP. GENERAL OFFICE AND FACTORY INDIANAPOLIS, INDIANA ' Sales Representatives in Principal Cities ENGINEERED VENT VALVES for STEAM and HOT WATER SYSTEMS VALVE NO. 1A 2A 70A 1000 40 500 CONN(IN.) H M H M H H RADIATOR--STEAM Adjustable for propor tional venting. . Vacuum--Adjustable for proportional venting. Meets Federal Spec. WW-V-151 for Type I Valve. Large Port--Extra large venting capacity. Single Port--For small one pipe systems. Disc type--For small one VALVE CONN. NO. (IN.) CONVECTORSTEAM IB w Adjustable for propor tional venting. - 71A 71A 71B 71C Single Port---Vents the air, seals against the y) escape of water and steam in modem con vectors that have high condensating rates. VALVE CONN. NO. (IN.) 4A M*K 16A 75. 75A V4x$ 75H 76, 76A XxH MAIN--STEAM Single Port--For small systems. - Single Port--Vacuum-- small systems. - Single Port--For medi um and large systems. Single Port--Vacuum-- For medium and large systems. VALVE NO. 500 790 791 79 78 CONN. (IN.) . WATER VENTS H Disc type--For radia tors. - H Single Port--30 psi-- For convectors. ' K Single Port--50 psi--For convectors and mains. Single Port--75 psi-- For mains. Single Port--150 psi-- For mains and process applications. SPECIAL VENTS VALVE CONN. NO. (IN.) 74 UNIT HEATER STEAM VENT Single Port--Vents with rising, steady, or fall ing pressure. STRAIGHT SHANK 41 H\ VENTS 43 H\ Single Port--For small 45 Mx*d * steam systems. ` THERMOSTATIC VENT 4 For use where water is not encountered. LOW, MEDIUM AND HIGH PRESSURE THERMOSTATIC TRAPS Low pressure traps have brass bod ies, caps and union nut and tailpiece. 17C is made in Angle, Swivel and Vertical patterns. SC is made in Angle and Straightway patterns. 9C is made in Angle pattern only. Thermostat and seat both renewable. No. 17C Capacity 200 sq ft EDR 25 lb pressure in. connection No. 8C Capacity 400 sq ft EDR 25 lb pressure K in. con nection No. 9C Capacity 700 sq ft EDR 25 lb pressure 1 in. con nection Medium Pressure Nos. 8 & 9 and High Pressure Nos. 8H & 9H have all bronze bodies and caps with union nut and tail piece. Thermostats are 6 diaphragms of special non-corrosive metal. Thermostats and seats are renewable. H in. sices are furnished in Angle, R.H., L.H. and Straightway patterns, others in Angle only. Medium Press. 50 lb. limit. High Press. 125 lb. F & T TRAPS, DIRT STRAINERS AND SUPPLY VALVES vL7vp.ly F4T ap 50 Series Float and Therm. Traps are available in pressure ranges to 125 lb. Used for venting and draining risers, steam mains, unit heaters, blast coils, etc. 50 Series Traps are made for easy servicing with all working parts mounted on cover. Remove four bolts to expose all parts. Pipe sizes are from in. to 2 in. cap. from 70 to 12,0001b condensate per hour. _ Radiator Supply Valves are made in sizes from ^ to 2 in. in Angle, R.H., L.H'., and Straightway patterns. Brass bodies, union nut and tailpiece. Nos. 180 and 185 have non-rising bandies. Both are packless. No. 186 is especially suited to vacuum systems. . Hoffman Y-Strainers are self-cleaning'. Available for 125 lb. 250 lb and 400 lb pressures. Semi-steel and Brass bodies. Should be used in line ahead of all traps, valves, and pumps. Available with brass and monel strainers. Series 600 HOFFMAN INVERTED BUCKET TRAPS Working Pressures to 250 lb Simple mechanism assures high op erating efficiency. Features include-- straight-through pipe connection; simple' seat adjustment; all working parts con nected to bonnet and easily removed with it; stainless steel seat and pin. Series 600 AS has integral Stainer. Sicja lad R*t Water 411 HOFFMAN SPECIALTY MFG. CORP. GENERAL OFFICE AND FACTORY INDIANAPOLIS, INDIANA Sales Representatives in Principal Cities WATCHMAN CONDENSATION PUMPS Condensation Pump A standard unit, single or duplex, for systems up to 12,000 so ft EDR ana 20 lb discharge pressure. A low cost, vertical type condensation pump with cast iron receiver. Pump is bronze fitted with stainless steel shaft, one-piece bronze impeller. Duplex units have two pumps, two motors, and two float switches. TYPE "UH" UNDERGROUND PUMPS "UHS" Single Unit Single or Duplex unite for systems up to 50,000 sq ft EDR. Units are equipped with single stage vertical type cen trifugal pump with cast iron receiver. Pump has enclosed type bronze impeller and stainless steel shaft. Special pits are not necessary with the Hoffman Under ground Pump. TYPE "VC" VACUUM PUMPS CONDENSATION AND VACUUM PUMPS . Hoffman pumps are available in varying capacities, a-c and d-c current, single, two, or three phase, and in pressures up to 60 lb. Condensation Pump Single and Duplex Units Capacities from 500 to 150,000 sq ft EDR Vacuum Pumps Single and Duplex Units Capacities from 2,500 to 100,000 sq ft EDR Individually sized and separately con trolled vacuum and condensate pumpe provide unusual flexi bility of arrangement and sizing. A wide, selection of vacuum VHD Full Duplex pumps and condensation pumps is inter changeable on a group of cast iron receivers so that an ideal assembly can be specified which will best serve the require ments of any particular application. Air capacities up to 70 cfm at 20 in. Hg vacuum. Condensation pump capacities up to 150 gpm and up to 75 psi. Duplex units provide double capacity. HOFFMAN TEMPERATURE REGULATORS Series 1100--for steam pressure to 150 lb per aq in. Standard temperature range, available between 80 F to 250 FT Other ranges available. Self-motivated. Hydraulically formed bellows of selected material. Rugged construction. For water heaters, convectors, fuel oil pre heaters and other similar applications. Single and double seated. Bronze and stainless steel trim available. HOFFMAN PRESSURE REDUCING VALVES Series 700 Max. Press. 200 psi.. Low Press. 1 to 15 psi. Scries 710 Max. Press. 250 psi., Low Press. 5 to 80 psi. . Series 715 Max. Press. 250 psi., Low Press. 2H to 125 psi. ' Series 720-S A 720-W Max. Press. 250 psi., Low Press. 2 to 125 psi. Series 750 Max. Press. 250 psi., Low Press. 2> to 25 psi. Choice of types specifically engi neered for your needs--continuous serv ice, or, for tight sealing against low pressure side when there is no de mand--and with typical Hoffman fea tures of design. "ZONET" ZONE CONTROL SYSTEM . "PANELMATIC" HOT WATER SYSTEM CONTROLS ...-ffftlft. - No; 193 Circulator Valve bJK^BI SyHD No. 201 Vent Tee No. 155 Flow Con* IBN3S . trol Valve - No. 250 Expansion Joint  412 Heating Systems Maid-O'-Mist, Inc. 3217 No. Pulaski Road Chicago 41, III. Manufacturers of Heating and Air Conditioning Specialties Products: Automatic air valves for (hydronic) hot water heating and cooling systems; automatic humidifiers for steam or hot water; automatic humidifiers for warm air furnaces; steam boiler water line controls; waterline float control valves; liquid gas and air strainers. . AUTO-VENT - Air Eliminators. Maid-O'-Mist Auto-Vents permit automatic venting of the air which causes circulation trouble in heating and cooling sys tems. More and more, contractors who value satisfied cus tomers axe fn-^tftHing these trouble stoppers. No. 7 Auto-Vent. For mains, pipe lines, unit heaters, chillers, convectors, coils, etc. Designed for vertical mounting only. Size 4H in. z 214 in. with Vi in. IP female connection. Made of brass and equipped with a self-closing, float operated valve. All working parts, including valve and copper Host, mounted on a removable bonnet for quick servicing or replacement. Valve is equipped with a Monel metal spring and a Neoprene valve seat which is unaffected by high temperatures, oil, anti freeze, etc. For pressure not exceeding 75 lb. - ' Venting trapped mains and circulating lines No. 77 Auto-Vent. Identical to No. 7 Auto-Vent, except for an additional % in., IP side opening to permit its use on overhead pipe lines, coils, etc., where head room is factor. Ideally suited fo - Diesel engine and cooling manifold use, where vibration demands secure mounting. No air chamber required. Auxiliary Equipment: No. 7X--bonnet assemblyfor No. 7 and 77; No.777--self-closing valve core; No. 7A--connector forsafe waste. No. 27 Auto-Vent For Horizontal Mounting Only with H *" ^ female side connection --Size 3 in. x io. No. 27 and 37 Atitd-Vents No. 37 Awto-Vent For Horizontal Mounting Only with ^ in. IF vertical male bottom connection--Size 3 in. r 2H in. For convectors or baseboard radiation;--high points of overhead Mains; Radiant Panels; small Doit Heaters. Construction and internal working parts are same as in No. 7 Auto-Vent. Made of non-ferrous metals and designed for pressure not over 50 ib. No air chamber required. Auxiliary Equipment: No. 27X--bonnet assembly for Nos. 27 and 37; No-. 7A--connector for safe waste. No. 666 valve core. ' 'Write for price sheet and descriptive literature. . No. 57 Auto-Vent No. 67 and 68 Auto-Vents For convectors and baseboard radiators. Designed for vertical mounting only. Size 3He in- x 114 in. with a H in. IP male con nection (or No. 67 and Y* in. IP connection for No. 68. Designed for limited space, small, self-closing, float operated valve may be installed in trouble spots previously neglected or improperly vented. Valve is equipped with .a Monel metal spring and Neoprene valve seat, which is unaffected by high temperature, oil, etc. No air chamber required. For pressures up to 30 lb. Where a Safe Waste is needed, specify No. 7A connector fitting. SmSVJSSaC1 Maid-O-MUt, Inc. ' No. 72 Auto-Vent For convectors, baseboard and free-standing radiation. Designed for both vertical and horizontal mounting. Size VA in. x 14 io. with Vs in. IP male connection. No. 72 Auto-Vent ib a fast venting self flushing valve of the expansion type. All expansion and contraction of the single, non-porous, composition disk is confined to four port vents. Internal siphon tube prevents waterlogging when installed in either vertical or horizonal position. Immediate drainage means fast disk drying, quick venting cycle which is continuous and no air chamber is needed. Manual venting features plus tight shut off we all controlled by valve cap adjustment. Valve cap is tamper-proof and can be removed and replaced without damage or special tools for cleaning or flushing, if needed. 413 No. 14, No. 15 and No. 16 Balancing Valve Adapter Units for Hot Water Heating and Cooling Systems No. 14 No. 15 No. 14 for copper and bronze tees. Nominal pipe sizes % in., in., * H in., 1 in., IK in.. No. 15 for tees. Sizes Yi in., H in., 1 in., IK in., 1)4 in. Maid-O'-Matic Valve Adapter Units make any copper, bronze, or cast brass or iron tee a balancing valve. These units, quickly soldered or sweat fitted into copperfi brass, and bronze tees or threaded into cast iron tees, regulate hot water Sow through radiators, convectors, baseboard panels, radiant coils, return mains, and branches. Can be inserted in side outlet or run of tee of same pipe-size to complete either a straightway or angle balancing valve. Full, free flow of water through the tee is pos sible. Since there is no inside reduction of pipe diameter, there is no water restriction except for the balancing required- This permits the use of additional balancing in a heating or cooling system without preliminary planning. Precision made of nonferrous metals. Simple balancing requires only a screw driver. CONVECTOR HUMIDIFIER No. 16 unit for H in. and 1 in. east brass tees to com plete angle balanc ing valves. Maid-0-Mist Convector Humidifier has do flat bottom to block the flow of warm air- Their individual H in.-copper water troughs are spaced 1 in. apart to allow unrestricted air flow between the evaporator pads. Maid-O'-Mist Convector Hu midifiers are designed for use with radiators cabinet con-' vectors in hot water heating systems and for all types of vans air furaances. 2 Trough Convector Humidifier, also available in 1 and 4 trough sizes No. SO SERIES FLOAT CONTROL VALVES The No. 50 Series Float Control Valves are precision designed to fill requirements for humidifying units, pan fillers, air conditioning equipment, evaporative coolers, air washers and other applications where dependable water level control is essential in limited space vanous No. 51 Float Control Valve. Only in. long overall, including copper float which is 2V4 in. diameter by 1V4 in. deep. Valve body is made of hex-brass rod with re movable, raised, hard nylon valve seat. Valve stem is brass with an incased heat and oil resistant, special Neoprene washer. Valve seat is protected with a 100 mesh Monel Metal screen. Valve body is fitted with two Vi in. IP locknuts for horizontal mounting securely in He in. bole--or valve may be screwed directly into tapped open ing. Supply is equipped with union coupling for Ya in. OD copper tubing. Working. pressures up to 85 lb with capacity of Vi gal per minute at 50 lb pressure. No. 52 High Duty Float Control Valve. Same general construction as No. 51 but designed for use where a larger volume of water is required- Capacity 1 gal (No. 52 float control valve) per minute at 50 Ib presure, with working pressures to 125 lb. Overall length 8 in. with oversized float lVi in. diameter by 4V4 in. long. No. 53Y High Duty Float Control Valve. Same general construction as No. 52 except valve is vertically mounted with specia bracket as integral part for mounting on reservoir or pan, well above water line. Only oK in. long. Non-back-siphoning when in stalled according to instructions. No. 54 Float Control Valve. Same general construction as No. 59 Valve except designed for use where a larger volume of water is required. Capacity 1 gal per minute at 50 Ib pressure. Overall length 5 in. No. 59 Float Control Valve. Same general construction as No. 51 valve, except valve is vertically mounted with special bracket as integral part for mounting on reservoir or pan, well above water Line. Non-back-siphoning when installed according to instructions. Only 5 in. tong. '. . NOTE: Nos. 51, 52, 53Y, 54, and 5Q tan be furnished with a H in. IP male connection at additional cost, when specified on order. Scries 6900--Water Line Float Control Diaphragm Valves. The No. 6900 Series float control valves are heavy duty large capacity water level controls. Rugged, strong and precision made, the cast brass body is fitted with a removable chromium valve seat. Con trolled water level is accomplished through the action oi the oversized copper float, linkage and special Neoprene diaphragm. Valve can be furnished to discharge water in an upward or downward position as specified. Can also be luraished with 8 in., 12 in., and 16 in. length float arm. Inlet and outlet tapping H in. IP. Capacities from IK gal to 6 gal per min. The No. 6927 Brass Mounting Plate 0 in. diameter) with gasket and screws is used where special mounting of the No. 6900 Series Valves isnecessary. Write for prices and descriptive literature. -  414 Heating Systems Sarco Company, Inc. SARCOTHERM CONTROLS, INC. 635 Madison Ave., New York 22, N. Y. Fully automatic weather modulated control systems for all types of heating, and all necessary accessories. Type ST A-2 for Hot Water and Radiant Heating Systems Hot Water and Radiant Heating Sarcotherm provides a carefully engineered control system for hot water or heating which is fully modulating, and allows continuous circulation. For forced hot water heating system for garden apartments, housing developments, hospitals, and institutions, Sarcotherm provides a com pletely zoned control system, including automatic night set-back and automatic morning pick-up. Steam Heating Systems The Type "W" Sarcotherm Control system can be applied to control con densate, vapor on low and high vacuum systems to promote fully modulat ing, continuous flow of steam in accordance with requirements of varying outdoor temperatures. . Complete program control panels and adjustment above or below normal requirements are provided. ' Engineering Assistance Consulting Engineers and Contractors are invited to consult with our En gineering Staff on any proposed control system. There is no obligation. Other Products. Room thermostate, lift traps, balancing fittings, dial thermometers, motor valves, cooling controls. . Radiator Trap, Type H SARCO RADIATOR TRAPS Type H for vacuum, vapor, or gravity steam systems:. Self-adjusting bronze bellows for highest vacuum to 25 psi. Body and cap of brass. Self aligning head and removable seat of hard bronze or stainless steel. Angle, straightway, offset, vertical, Vi to 1 in. Cot. N SS6. Type 40 Type SM SARCO RADIATOR VALVES Type 40--Bellows Packless--for steam heating. Valve stem sealed by packless bronze bellows, balanced pressure type. Angle or globe, Vs* to 1 Vi in. . Brass body, reversible discs, bakelite handle. Available with modulat ing devices. Wheel or extension handles; lockshield tops. Cat. iV 55. Type SM__ Spring-packless or gland packed for all steam and hot water systems. Angle, globe, offset, Vi to 2 in. Same details as for above type 40. Cat. N SS5. SARCO N-100 TRAPS Similar in style to above Sarco Radiator Trap, the N-100 Thermostatic Trap is suitable for operation at pressures up to 125 psi. Stainless steel renewable valve head and seat. Angle, straightway and vertical. Sizes Vs in. to 1 in. Bulletin N155. . Sarco Companyt !nc. 415 Float-Thermostatic Trap Inverted Bucket Trap ' Thermo-Dynamic Trap Finned-Tube Radiation Typo S Condensate Pump SARCO FLOAT-THERMOSTATIC STEAM TRAPS Discharge condensate at steam temperature, continuously and without shock. Automatically vent air and gases by built-in thermostatic by-pass. Immediately responsive to varying loads and pressures. Sizes Vi in. to 2Yi in. for pressures to 200 psi. Catalogs No. N-450 and N-455. - SARCO INVERTED BUCKET TRAPS Sarco Camlift valve mechanism provides rapid and free discharge of the condensate. Special design to prevent prime loss on light loads. Sizes Vi in. to 2 in., for pressures to 900 psi. Catalog Ni$60. SARCO THERMO-DYNAMIC STEAM TRAPS These new type traps virtually eliminate maintenance. Stainless steel throughout ... immune to both internal and external corrosion. Safe in fire-hazard locations. Not affected by corrosive condensate, superheat, water-hammer. Only moving part is solid stainless steel disc. No valve closing mechanism to wear or stick. No critical clearances to choke. No gaskets to leak. Same trap for pressures 10-600 psi. Sizes Vs in. to 1 in. Bidletin No. N-B57. ' SARCO PIPELINE STRAINERS (Also Scraper Strainers) Brass, semi-steel or cast steel for all commercial pressures. Also furnished with hand or motor operated rotary scrapers, which clean the screen with out flow interruption. Catalogs No. N-I200, N-1210, and N-1225. . SARCO SELF-POWERED TEMPERATURE REGULATORS These self-powered units use the uniform force of liquid expansion. No stuffing boxes to leak, no auxiliary "power" required. All moving parts are inside the regulator. For steam, gas, oil, water or brine for temperatures - to 300T. Bulletin N-620 and N-625. SARCO WATER BLENDERS AND TEMPERING VALVES For automatic mixing of hot and cold water at desired temperatures. Type MB for showers, wash basins, etc. Type DB for use with submerged heat-, mg coilsor tankless heaters. Bulletin NSOO. . SARCO AIR ELIMINATORS ^ For steam and hot water heating systems, chilled water lines. Semi-steel or cast brass body. Vs in. and 1 in. Bulletin N J70. SARCOFIN FINNED-TUBE. AND BASEBOARD RADIATION A complete line with approved ratings as established by Institute of Boiler and Radiator Manufacturers. Bulletins Nos. N-I64O, N-1650, and N-1660. ' SARCO CONDENSATE AND VACUUM PUMPS Complete line of condensate and vacuum pumps for all capacity ranges. Bulletin N-1465. .  416 Heating Systems WARREN WEBSTER HEATING . . . COOLING WARREN WEBSTER & CO., 1731 FEDERAL ST., CAMDEN 5, N. J. * SINCE 1888 Representatives in Principal Cities--Consult Telephone Directory RADIATION AND HOT WATER SPECIALTIES Webster Walvector Radiation Webster Steel-Fin Radiation Webster Baseboard Heating Webster Hydro-Heat Specialties Webster Convector Radiators Webster Unit Heaters HPATnvr SPECIALTIES ' Webster Thermostatic Traps Webster Radiator Valves Webster Float and Thermostatic Traps Webster Process Steam Traps Webster Dirt Strainers Webster Lift Fittings - Webster Double Service Valve Webster Boiler Protector CONTROLS, ' Webster Continuous Flow Control Webster Moderator Systems Webster Control Valves AIR CONDITIONING Webster Riviera Heating-Cooling Conditioners Webster Newport Air Conditioners WEBSTER TRU-PERIMETER HEATING Webster Tru-Perimeter Heating uses Webster Wal vector and/or Webster Baseboard to replace beat at the perimeter, where heat loss occurs. Heating ele ments are mounted close to the floor along outside walls, spreading gentle heat the entire length of the exposed walls. Webster Tru-Perimeter Heating warms the air, the floors, and the inside surface of outside walls. Air isdrawn to floor level and across floor into inlet opening of radiation. Radiant heat rays strike the floor along the full length of exposed walls. Webster Walvector Webster Walvector for steam or forced hot water beat ing is an elongated convector designed for mounting along the wall, close to the floor line and under win dows. For new buildings or modernization. Combines an attractive steel enclosure newly styled and im proved, and a highly efficient heating element of copper tubing and aluminum fins in 3 in. and 4 in. fin sizes. Features simplified, low-cost, one man installation. Custom Webster Walvector employs 3 in. or 4 in. fin size heating elements, single or double row. Front or top outlet enclosures for wall mounting or with integral sill. Custom Webster Walvector is custom made to meet architectural and construction require ments . .. yet sufficiently standard to permit produc tion on an economical basis. Deluxe Webster Walvector combines all the ad- * (Mbkwaf T'^nipnuni * Warren Webster & Company 417 Exploded view of Webster Walvector showing component parts Cut-away view showing design simplicity of Webster Tru- Perimeter Baseboard vantages of Standard Webster Walvector with a wider choice of enclosure, special wall trim and caps to achieve pleasing lower alignment and clear, simple lines: Versatile lower outlet location puts the heat where needed--excellent for panel wall construction. Ask for Bulletins on Walvector, Custom Webster Walveetor and Deluxe Webster Walvector. Webster Baseboard Heating Webster Baseboard Heating is a forced hot water system _in which a convector heating element is con cealed within a specially built metal baseboard. It is run in a continuous loop around the exposed walls of the house, with a separate loop for each floor or zone. Heating element is copper tubing with aluminum fins. Send for bulletin. WEBSTER AIR CONDITIONING Webster Newport: Provides heating and cooling in a single compact cabinet for through-the-wall installa tion. Contains.heating coil for connection to steam or forced hot water heating system, and self-contained hermetically-sealed refrigeration cycle. Provides easy, inexpensive way to modernize hotels, office buildings, apartments or motels. ' Webster Riviera Heating-Cooling Conditioner: Cab inet-contained unit utilizes same piping for winter heat ing with warm water and summer cooling with chilled water. Boiler and chiller are connected in parallel and fitted with valves for seasonal change-over. Ask for bulletins. Tile Webster Newport in this well-styled executive office illustrates bow this modern unit will complement any decor Model C-160 Webster Riviera Heat-Cooling Conditioner  418 Henting Systems s*< Illinois Engineering Company 2059 South Racine Avenue Chicago 8, Illinois Division of 'American Air Filter Company, Inc. HEATING SPECIALTIES CONTROL SYSTEMS POWER SPECIALTIES HEATING SPECIALTIES Float and Thermostatic Traps Series G For Low Pressure Service .. Compact, simple, accessible, durable, dirt-proof. Pos itive valve action. Wire drawing impossible. Low dis- . charge temperatures. Efficient air venting. Trap not damaged by freezing. Recommended Applications For draining Low Pressure Heating Systems, Ventilating Units, Unit Heaters, Pre-Heaters, Re-Heaters, and other Fan System Heat Surface, Process Heaters, Hot Water Generators, Drips of Mains and Risers. Series G operating ranges from 25 inches vacuum to 15 lbs. pressure. Illinois Radiator Supply Valves Quick Opening, Spring Loaded, Packless. For any twopipe steam, vapor or vacuum heating system. Extremely smooth and easy to operate with a cool, break-proof plastic handle for finger tip control. iDmots Thermostatic Trap Series G For Vacuum and Vapor Heating Systems--For Work ing Pressure Up to 15 Pounds Positive acting and re sponsive to the slightest temperature changes, it dis charges condensate quickly and freely without loss of live steam. Illinois Thermostatic Traps for High Pressures Series HG--Maximum working pressure 150 pounds. Used , where neat appearance and compactness are'de sirable, as for trapping sterilizers or water stills in hos pitals; steam jacketed kettles, coffee urns, warming tables and for process work. These traps are also furnished for medium pressures. OTHER PRODUCTS Air Vent Traps Strainers Boiler Return Traps Power Specialties Control Valves Vacuum and Condensate Pumps Convectors Control Systems Hot Water^Specialties Pressure Regulating Valves Scries 6 Series KG Trap Heating Systems 419 A. W. CASH VALVE MFC. CORP. 666 E. Wabash Avenue CASH-ACME Decatur, III. Representatives in principal cities. See the . `Waive*' Classification in the Yellov Pages of your local telephone directory AUTOMATIC VALVES; BOILER PRESSURE CONTROLS; RELIEF VALVES; BACK PRESSURE VALVES; PRESSURE REDUCING AND REGULATING VALVES BOILER PRESSURE CONTROLS TYPE "CQ" TYPE "CQ" DUAL CONTROL~Combines pressure reducing boiler feeder with a positive ASHE listed relief valve in one body, plus an easily accessible in built strainer. All bronze, body, silicone relief seat. High relief design for good water or emergency steam relief. Keeps water in system above 13 psi and below 30 psi continuously and automatically. TYPE "CBL" TYPE "CBL" DUAL CONTROL-- Combination reducing and regulating valve, by-pass valve and positive relief valve all in one body. Automatically keeps heating system filled with water above 13 psi and below 30 psi. Relief side protects against high pressure due to thermal expansion. By-pass affords quick filling at higher pressures. RELIEF VALVES AND SAFETY DEVICES TYPE "F-51-P-52"--ASMS tested and rated safety relief valves for hot water space beating boilers, larger storage tanks and water heaters. Fully meets ASHE requirements in safe-guarding against maximum steam a boiler might generate in runaway conditions. Avail able with male and female inlets in sizes %, in, to 2 in. TYPE "V" TYPE "FV" TYPE "V,"--Offers twofold protection for hot water heaters. Relieves in condi tions of both excessive pressure and dangerous temperatures. Contains a new patented solid-filled thermostat. Reseat ing is automatic when dangerous condi tions subside. Pressure setting from 50 psi to 175 psi available. in. or in. size. A.O.A. listed. TYPE "FV"--Provides maximum tank and heater protection. Combination pressure and temperature relief valve. Contains new patented solid-filled thermostat, eliminating fuse plug re placement. Bronze bodies, brass internal parts, silicone seat discs. Pressure settings 75 to 150 lb. Test lever standard on all models. Size in. ASHE and A.G.A. listed. BACK PRESSURE VALVES ' TYPE FR BACK PRESSURE RELIEF VALVE-- High quality industrial type. Iron or bronze; suitable up to 400 psi. For prac tically any service (except steam). Unusually accurate control; good ca pacity. M in. to 2 in. sizes. iSP JaSEk 139K . KaESP TYPE "FHTL" P,I^I>H5AGM PRESSURE RE- LrfcJVTT, water heaters, storage tanks, eVr; A1| bronze. A.6.A. listed. With or flnthout test lever and temperature fuse P*u8- H in, in. and 1 in. sixes. PRESSURE REDUCING AND REGULATING VALVES TYPE "B" TYPE "B"--Industrie! type pressure reducing valve, designed for maintaining desired pressure in service line regardless of fluctuations in pressure from supply. Available with pressure settings of 2 to 200 psi, and for gas or fluid service K in. to 2 in. sizes. TYPE "E"--Water pressure reducing valve designed for domestic supply service. Keeps pressurein homes at 45psi or whatever pressure is desired. All bronze, large in-built strainer with sepa rate cleanout. Maximum inlet 250 psi. 1 in. to 2 in. sizes. TYPE "BBC'* PRESSURE REDUCING AND REGU LATING VALVE--Similar to Type "B" above except modification for heavy, dirty or viscous fluids, including Bunker "C" Oil- Stainless steel working parts. Features new "universal" joint seat, assures good operation. % in. to IK jn. sizes. TYPE "F-3T" TYPE "F-3T"--Newly designed offset valve body permits replacement of short or 6 in. fuse extension without removing or disassembling valve. Relieves from both pressure and temperature excesses. Pressure setting 25 to 200 lb. Fuse plug melts at 210 F. Also available with fuse plug in side of straight valve body. H in. and 3 in. sizes. ' ' DIFFERENTIAL PRESSURE REGU LATOR--For controlling desired rate of flow by maintaining constant pressure "drop" across an onfice. Suitable for Bunker "C" oil. % in. to 1)4 in. axes. TYPE "BH"  420 Heating Systems vd, Air THE DOLE VALVE COMPANY Plumbing and Heating Division 6201 Oakton Street, Morton Grove, (Chicago Suburb), III. WATER MIXERS AUTOMATIC REGISTERS AIR and VACUUM VALVES The AU Star line Control with DOLE ' DOLE 20 SR. VENT (LEFT) This high-quality hot water air valve is designed to provide an automatic air eliminator, a manual shutoff and a manual air vent. A Dole design developed on the hygroscopic prin ciple by The Dole Valve. Company. A selector dial permits various settings and provides for faster venting. One of a complete line of Dole Hot Water Air Valves. DOLE NO. 100 WATER MIXER (RIGHT) - Here is a new water mixing valve utilising the famous Dole element which gives extra power. It is noncorrosive and trouble-free. The No. 100 is made of a brass forging and yet despite its high quality is low in cost, making it a top value. Nonadjustable. 140 deg setting. Designed for installation at the water heater or storage tank. DOLE AIR VALVES The complete Dole line includes air valves for every type of - heating system. Below are six typical valves from the line. DOLE NO. 1 A VARI-VENT--adjustable valve that provides an infinite number of venting speeds. DOLE NO. 1 D--a very fast venting, fixed-orifice, nonadjustable air valve- Factory-set to vent two or three times as fast as regular type air valves. * DOLE NO. 1 B VARI-VENT--provides better control of heat on convector type radiation where faster venting is essential. DOLE NO. 3--designed to assure utmost beating performance on hand-fired steam heating systems. Complete venting is assured at any pressure up to 10 lbs. DOLE NO. 4 QUICK VENT VALVE--for quick venting steam m<Aing and returns up to 25 lbs pressure. DOLE2 B VARI-VENT VACUUM VALVE--for use on handfired gravity one-pipe steam heating systems. Has the Dole patented bellows that locks air out once it has been expelled. DOLE WATER MIXERS Dole Water Mixers provide safer tempered domestic hot water on all +-gTiirl*>gg heaters and storage tank iostall&tions. Avail able in three sices: H in., Yt, in. and 1 in.; adjustable range- 125 to 175 deg F. ' DOLE AUTOMATIC REGISTER Provides individual room temperature control. Operates ther mostatically from room, air temperature. Completely selfcontained. Dial permits setting for the heat desired. Made in rises to fit' practically any stack-head opening. Healing Systems vk, THE FAIRBANKS COMPANY 421 EXECUTIVE OFFICE: 393 LAFAYETTE STREET, NEW YORK 3, N.Y. Branches: Boston, Chicago, New York, Pittsburgh and Rome, Ga. Plants: Binghamton, New York and Rome, Ga. Dependable Service GUARANTEED From This Complete Line of Bronze And Iron Body Valves Available From Your Local Distributor BRONZE GLOBE AND ANGLE VALVES NO OTHER Pressures--125 through 300 lb SWP Ends--Screwed, Flanged, Solder, Braced sad Hose. Discs--Bronze: Renewable Composition: Nickel Alloy Semi-Plug Disc and Seat Stainlea- Steel Semi- and Full Plug Disc and Seat. Needle Valves ' Radiator Valves LP--Gas and Oxygen Valves VALVE IN THE WORLD LOOKS LIKE THIS BRONZE GATE VALVES Fig. U-01 150 lb SWP Fig. U-0252 m lb SWP Fig. 0702 125 lb SWP Pressures--125 through 300 lb SWP. Ends--Screwed, Flanged, Solder, Brazed and Hose. . Stem Action--Rising with Solid or Double Taper Wedges, Non-Rising with Solid Wedsres Bonnets--Screwed, Union, Bolted and O. S. A Y. Radiator Valves LP--Gas Valves ... BRONZE CHECK VALVES Horizontal, Angle and Vertical Types--Swing and Lift ._ Pressures--125 through 300 ib"SWP Ends--Screwed, Flanged, Solder and Brazed. Discs--Bronze, Renewable Composition, Rubber Faced. ' LP--Gas Valves IRON BODY GLOBE AND ANGLE VALVES Bronze Mounted Pressures--125 through 250 lb SWP Ends--Screwed and Flanged Discs--Bronze, Renewable Composition., Nickel Alloy Semi-Plug Disc and Seat, 500 Brinell Stainless Steel Plug Disc and Seat Bonnets--O. S. A Y. and Union Automatic Stop and Check Valves IRON BODY GATE VALVES Bronze Mounted and All Iron Pressures--125 through 250 lb SWP Ends--Screwed, Flanged and Hub Stem Action--Rising, Non-Rising and Quick Opening ' Wedges--Solid and Double Disc Bonnets--Screwed, U-Bolt, Bolted and 0. 8. A Y. UNDERWRITERS', FACTORY MU TUAL, and AWWA Approved Valves ' IRON BODY SWING CHECK VALVES Horizontal--Bronze Mounted Pressures--125 through 250 lb SWP Ends--Screwed and Flanged. Discs--Bronze, or Rubber. UNDERWRITERS' and FACTORY MUTUAL Approved Valves. WHEN YOU REMOVE THE BONNET FAIRBANKS (patented) RENEWABLE SEAT RING BRONZE GATE VALVES NEVER HAS TO BE REMOVED FROM THE LINE TO REPLACE SEAT RINGS  422 Heating Systems JENKINS BROS. 100 Park Avenue, New York 17, N. Y. Bridgeport, Conn.; Boston, Philadelphia, Chicago, San Francisco, Atlanta DO YOU HAVE THIS HELPER? FOUR TYPES OF INDEXES LEAD QUICKLY TO DATA NELOtO Four-way indexing--General, Alphabetical, Fig. No,, and Sec tional--leads the reader instantly to the information desired, from any point of reference...pattern, metal, number, or function. VALVE SPECIFICATIONS UST ADVANTAGES AND MAJOR USES Every Jenkins Valve in every group,--Bronze, -Iron, Cast Sleel, and Stainless Steel--i$ fully illus trated and described in detail, with an explanation of its prin cipal advantages and uses. HELPFUL INSTRUCTIONS FOR CHOOSING AND USING VALVES Thirteen pages of basic informa tion,--"Fundamentals of Valve Design and Application"--serve as a guide in selecting the correct type of valve, and provide instruc tions tor their proper installation and maintenance to assure maxi mum service life. ' For clear, complete, easy-lo-find data on valves and bow to select and use them, reach for this latest Jenkins Catalog. USEFUL TABLES AND REFERENCE OATA TO WIN FAVOR OF ENGINEERS In the 23 pages of the "Engineer ing Data" section, Catalog No. 56 provides a compilation of useful required tables, charts, and codes --the information wanted by the men who plan piping layouts ... and specify valves. From cover to cover this 296 page genera) catalog of Jenkins Valves was designed to give specifiers and buyers all the data they want.. . and FAST. It's the book to reach for FIRST when you need valves or valve information. Write for your copy. Heating Systems - Specuuu 423 JAS. P. MARSH CORPORATION Marsh Instrument and Valve Co. (Canada) Ltd., 8407 103rd St., Edmonton, Alberta. Dept. .5, Skokie, Illinois Branches in Principal Cities Houston Branch Plant: 1121 Rothwell St., Sect. 15, Houston, Texas. Marsh products include: Pressure, Vacuum and Compound Gages; Dial Thermom eters; Steam Traps; Vents; Packiess Radiator Valves and Radiator Traps; Refrig eration Water Regulators; Refrigeration Testing Instruments; Solenoid Valves; Needle Throttling Valves. Radiator Traps--Equipped with the famous Marsh phosphor bronze diaphragm charged with volatile fluid. Extremely rugged, but ao sensitive it closes tight on steam and opens instantly to pas3 condensate and air at only a few degrees below closing temperature. Highly efficient on pressures from below atmos pheric up to 25 psi. Other traps available for pressures up to 125 psi. Pressure Ganges and Dial Thermometer*--1The respected Marsh line covers every requirement for pressure, compound, altitude gauges, ther-altimetera and dial thermometers. Marsh instruments are the product of nearly a century of experience. Sizes, ranges and case styles for all needs. Marsh Radiator Trap and Packless Valve. Both are available in full range of patterns. Packiess Radiator Valves--rNot just packles..in name; the ingenious Marsh annular mechanical seal does away with packing of any kind. Valves close on less than one turn. For either steam or hot water. Maximum water pressure, 125 psi. Float and Thermostatic Traps--De signed for complete removal of air and condensate from steam mains, branches and risers. Condensate discharged through float operated valve at bottom; air through vent in top. Wide range of pres* sure sod capacity ratings. One., of the many float and thermostatic traps is illus trated. Line alao includes float traps. Refrigeration Valves--Recent addition to the Marsh tine of water regulating valves is the Type 56 pressure actuated regulator illustrated. It is adjustable for both Refrigerant 12 and 22--adjustable from 60 to 270 psi--by simply twisting handy knurled cap on bottom. Although small and compact for installation in tight quarters, it has ample capacity for wide range of applications. Other Marsh Water Regulators, both temperature and pressure actuated, for practically every cooling or heating application. Marsh Type 56 Regulator, made in sizes of % in., K in., % in. and 1 in. Other types available. Inverted Bucket Trap*---Marsh quality and performance in a trap for applica tions where the inverted bucket type is indicated. ,_ . _ Marsh Inverted Bucket Trap. Marsh No. 50 Air Vent Air Vents--Automatically remove air and gases from tanks, coils or piping, liquid pump systems, and other similar applications. Float holds valve tightly closed when system is filled. Opens only when air accummulates. Has vacuum check which prevents return of air. Type illustrated is for working pressures up to 125 psi- Other types, including float and thermostatic types," for low pressure. Solenoid Valves--Bodies made from solid bar stock. Packiess, smooth-operat ing, tight seating valves with coils that withstand frost and moisture. / Ask for catalog The comprehensive Marsh line is merely high-lighted here. Ask for catalog infor mation covering your specific needs. Marsh Solenoid Stop Valve. Di rect acting and pilot operated valves which cover a broad range of require ments.  424 Heating Systems vKct u4 FMap MUELLER BRASS CO. PORT HURON 12, MICHIGAN WROT-SOLDER TYPE FITTINGS Manufactured from seamless copper tub- Log. Uniform solder cup depths; solder- ing temperatures reached quickly. Available for all plumbing, heating and air-conditioning systems. ' FLARE FITTINGS Accurately machined threads for tight, leak-proof joints. Made from forgingB or drawn brass rod to eliminate porosity. DRIERS, FILTERS, STRAINERS Many styles and sues to fit every instal lation requirement including new Drymaster with balanced filtering and dry ing combined in one unit, also Deluxe Driers, versatile angle-type drier-strainer; Guardsman Drier, an angle strainer and a Y-type water strainer. COMPRESSOR VALVES Made of either forged brass or all steel, Mueller Brass Co. compressor valves are sturdy and dependable. Single, double port or adjustable .. - available in both flare and solder type connections in many sizes. REFRIGERATION VALVES Diaphragm and packed valves for re frigeration and air-conditioning service have forged brass bodies. Carefully engi neered and constructed of highest grade materials to give long trouble-free service on every installation. Many sizes in line, angle, two-way and three-way, either backdating or non backseating types. CAST BRASS WATER VALVES Streamline cast bronze or forged brass valves. Packless and packed types variety of and styles. Compression stops, gate, globe, swing, check and valves in various end connections available. 125 psi, 150 psi water, oil, gas service. COPPER TUBING Fine quality dehydrated and sealed cop per tubing of dead soft temper. No mois ture or foreign particles. Hard-drawn copper in straight lengths available in variety of outside diameters. LIQUID INDICATORS Available in straight-through, single or double port models with flare or solder end connections. Versatile new Sightmaster employs light refraction to indi cate refrigerant supply. Easy, leak-proof, trouble-free installation. SAFETYMASTER RELIEF VALVES Designed and engineered for positive instantaneous action with exceptionally high volume discharge. Built to satisfy ASA B5 code requirements for refrig eration vessels safety devices. Available in either straight-thru or angle types, in a total of 12 different inlet and outlet size combinations. Pressure settings from 150 to 450 lbs. Strong, Carlisle & Hammond 508 Sandusky Street, Conneaut, Ohio The Complete Steam Specialties Line STRONG HYDRO-FLEX STEAM TRAPS (semi-steel} for pressures to 230 psi, temperatures to 450 F Strong Hydro-Flex Steam Traps feature quick, positive lever-lift action for high discharge capacity and unmatched performance on light or heavy loads. There are only two mov ing parts--bucket and lever--reducing wear to a minimum. Pins, fixed fulcrums and hinges are eliminated from larger traps. Screwed-in renewable valve and seat are of wear-re sistant AntOT-lfetf, guaranteed leakproof for one year. AH internal parts are stainless steel and attached to the cover for ease of maintenance. 140 Series Standard In-Line Traps and Blast Traps ' STRAINERS Strong Strainers collect foreign matter to protect expensive equipment, reduce maintenance and servicing on pressure and temperature regulating valves, steam traps and other fittings in heating systems. Standard screen is stainless, with 0.027 in. perforations. Stainless screens with 0.045 in., 0.062 in. and 0.125 in. perforations are available at do extra cost. Special screens furnished at extra cost. Semi-Steel Strainers 141-T and 142-T 143 and 144 140-S and 141-S Side inlet and ode outlet permit quick removal of cover for maintenance with out disturbing piping connections. Extra bottom connection is provided for drain ing or cleaning. . 140-S Series has built-in strainer for removal of foreign matter in the line to prevent clogging of the trap. ' 140-T Series Blast Traps have ther- ma\ ven^ fr use on jobs requiring very rapid starting or excessive air capacity. Type "SY" with bush ing for blow^>fT con nection. Screwed pipe connections. Type "SYG" with cap ana gasket for blow-off connection. Screwed pipe connections. Ductile Iron Strainers Type "SYD" strainers are made of Ductile (Nodular) Iron that can be bent or twisted without breaking in case of fire or explosion. Suitable for steam pressures of 600 psi at 650 F. 40 Series Standard Bottom Inlet Traps 43. 44, 45 and 46 . Heavy-duty bottom inlet, top outlet traps for severe service on low, medium and high pressures to 250 psi at 450 F. Long operating life at sustained high efficiency with minimum maintenance. Where excessive sir venting is re quired, the Strong Thermal Bucket Vent with a bi-metal element is available. Type C : Pilot-operated, single-seated, packlea valve. Recommended for installations re quiring the most accurate and dependable regu lation. Semi-steel or cast steel construction. Reduced pressures from 0 to 200 psi. Screwed connections on sizes under 2 in. Others flanged. Type "K": Self-contained, direct-operated valve for a maximum initial pressure of 225 psi for reduced pressures from 0 to 85 psi. Has in ternal strainer: Screwed connections. Type "O": Same as "K", except for sizes and no internal strainer. Screwed connections. Type ' Tn, No. Pipe Sue (w.) Cootinoous Capacity at psi lb/hi Wa*bt <S> List Pricq <3 H-H 300 1520 ISO 3380 4070 350 8750 31400 84 90.00 Type "K" NoU: When ordering. alvay* itita bichest prtiaure. For more information write for condensed Bulletin No. SS-UO-B or General Catalog No. 69-A. WATTS REGULATOR COMPANY 10 Embankment St., Lawrence, Massachusetts BELIEF VALVES AND CONTROLS FOR HOT WATER SPACE HEATING HOT WATER SUPPLY SYSTEMS PRESSURE RELIEF VALVES FOR HOT WATER HEATING BOILERS (A-S.MJi. Rated) 174A Series - For dependable protection against over pressure. A complete line of sizes, 3-in. to 2-in. inclusive. Bronze body and internal trim. Non-mechanically guided, stick&ge-free design. 74A and 740 Series ' These valves are the same as the 174A Series except for in creased outlets to provide greater capacity. Both series are tested and rated by the National Board of Boiler and Pressure Vessel Inspectors. Size M' f. *kiz `.Model Ml No. 174A 174-A* 174A 174A 174A 74A 740 740 arifR Pmx. Stexm Rxunx Bto/br 30 lb 36 lb 45 lb 800.000 1,000,000 1.05.000 3.020.000 3.815.000 700,000 3.900.000 5.3SO.OCO 575.000 1.145.000 3.130.000 3.310.000 4.300.000 795.000 3.335.000 5.975.000 1.355.000 3.505.000 3.730.000 5.130.000 040.000 3.935.000 7.050.000 SELF-CLOSING TEMPERATURE AND PRES SURE RELIEF VALVES (A.S.M.E. and A.C.A. Rated) 40. 140. 240. 340 Series For hot water supply system protection. Available in short or extended type thermal elements. Temperature relief 2L0`SF. Pressure range 75-150 lbs. Standard setting 125 ibs. Sizes, %-iu. to inlet connections. Female outlet connections. Type No. Coonectiota Inlet Drain Thomastn Temperature Wxter Kiting Btu/hr 40L 4QXL 1408 140X 141S 141X 340 34] 340 $ 1* m 1' m 1' 1)4' Wf M'f M'f M'l M* f I' 1 1'f wrt Short Extension Short Extension Short Extension Extension Extension Abort 750,030 750.000 850.000 550.000 850.000 850.000 1,000,000 . 1.000.000 3.500.000 (1) female'cfootction--(ml mate connection ASUB PRES SURE STEAM RATING (Valve set at 125 lb) Btu/br 1.317.600 1.317.600 1.217.600 1.217.600 1.217.600 1.467.000 1.467.000 5.707.000 No. 560 Automatically supplies water as needed to maintain minimum system pressure under normal operating conditions. Regulator is set to deliver 12-15 lbs, but may . be adjusted to higher pressures. Female inlet and outlet connections. Sizes, H*iQ- and $-in. TEMPERATURE ONLY RELIEF VALVES (A.G.A. Listed only) Nos. 400T. 401T Temperature only relief valves for hot water supply tanks and heaters where separate temperature relief' valves are desired or required. Btu/hr ratings up to 1,000,000. Sizes, % in. or 1 in. inlet, % in. female' outlet. Available with fixture con nection. Belief VeMec, Central. Watts Regulator Co. STEAM BOILER WATER LEVEL CONTROLS 427 BOILER WATER FEEDERS AND FEEDER CUT OFF COMBINATIONS (Listed by Underwriters' Lab.) LOW WATER CUT-OFFS (Listed by Underwriters' Lab.) No. 89A Feeder automatically feeds water to maintain safe water level - Maximum steam pressure 25 lbs. Gage glass type with deep in boiler. Cut-off switch interrupts burner circuit in the event sediment chamber. Available with single throw mercury switch of an emergency low water condition. 60 Series . for cut-off service only, or double throw for cut-off and alarm . service. Mimnm steam pressure 25 lbs. Gage glass type. in. feed . Ideally suited for self-energized control circuits on valve connections. Available as feeder only or combination gas-fired heating installations. feeder and cut-off. Up to 5,000 sq ft radiation. 76 Series Maximum steam pressure 55 lbs. Larger float and body design. Available in same models as 60 Series. ^ in. feed valve con - nections. Float chamber connections 1 in. female. For over 5,000 sq ft radiation. No. 50A Maximum steam pressure 50 lbs. Heavier float and bellows construction for use on small and medium size process boilers as low water cut-off. or pump starter. Also used on hot water heating boilers. 1 in. female top and bottom float chamber connections. See diagram on facing page. PRESSURE REDUCING VALVES FOR WATER AND STEAM SERVICE REGULATORS FOR WATER SERVICE No. 223S High capacity water pressure reducing valve with separate strainer attached. For initial pressures up to 250 lb. Reduced pressure range 30-75 lb. Sizes to 2 in. No. 13S Water pressure reducing valve and integral stainless steel strainer. For water or air service on household and industrial applications. Initial pressures up to 250 lb. Sizes, M in. to 2 in. inclusive. 135LP for reduced pressures under 30 (b. No. 127W Remote control, diaphragm-operated spring type pressure re ducing valve. Sizes, M in. to 3 in. Initial pressures up to 250 lb. Reducing pressure range 10-100 lb. No. 155 REGULATORS FOR STEAM SERVICE No. 127SC and No. 12S X No. 127SC is spring type and No. 125 weight and lever type remote control diaphragm regulators. Sizes, in. to 3 in. in clusive. Initial pressures up to 250 lb. Reduced pressure range range 1-100 lb. Sizes id. and 3 in. available with flanged connections. Also available as double seated regulators in rises up to 6 in. Stainless steel trim. .- No. 152 Self-contained type. Sizes, in. to 1 in. Initial pressures up to 250 lbs. Reduced pressure range 5-40 or 25-100 lb. No. 155 and No. 25? These.regulators are for controlling the temperature of liquids in vats, pipe lines, tanks, etc. No. 155 single seated. No. 255 double seated direct acting regulators. Sizes, in. to 1}{ in. inclusive. No. 257 is reverse acting, double seated regulator. Sizes H in., $ in., and 1 in.  428 ItUUlation CowJwH 4 Dn4nra< American Gilsonite Company Municipal Airport P. O. Box 15, Salt Lake City, Utah Eastern Office: 3537 Lee Road, Cleveland 20, Ohio Distributors in principal countries of the world Affiliate of Barber Oil Corporation and Standard Oil Company of California ULATE* TRIPLE ZONE INSULATION FOR UNDERGROUND HOT PIPES GDUSULATE is & solidified hydrocarbon of high resin content which in granular form is poured directly around under ground hot pipes for insulation and cor-' rosion protection. - GENERAL DATA 1. Low cost per installed linear foot 2. Easy-to-use: pour ... tamp ... nor mal pipe heat does the rest 3. Fuses itself in hours into 3 tones of permanent protection for the pipe ' against all commonly-encountered buried-line conditions such as acids, nlVnllpg, roots, water, and corrosion 4. Tested and proved in actual use in hundreds of new construction and re placement installations. 5. Can be used under all multiple-pipe and cramped space conditions (see il lustration below) - 6. Needs no housing or mechanical sheaths to protect it 7. Requires no mining or special han dling . 8. Can't be punctured, obviating need to remove rocks from backfill 9. Only normal pipe spacing required; steam and condensate lines can run side by side 10. Pipe eypands and contracts within chlsulate structure 11. Makes repaira to the pipe quick, easy nnrl economical GRADES AND TEMPERATURE RANGES Type A............................... 220F Type B............................... 300F Type C............................... 3S5F to300F to385F to520F TRENCH SIZE 4 in. to 22 in- wider than pipe diameter, 12 in. minimum backfill over the <ulsulatb bed. EFFICIENCY Heat loss 8-12 percent of bare pipe. Inert to ordinary acids and alkalies found in soil, excellent dielectric. For further data or information, write: American Gilsonite Co., Municipal Air Port P.0. Box 15, Salt Lake City, Utah, or 3537 Lee Rd., Cleveland 20, Ohio. ZONE 1 Dense, semi-plastic coating bonded tightly to pipe surface permits pipe to expand and contract while pipe wall is hot. Zone is waterproof and a thermal and electrical insulator. ZONE 2 Sintered rone provides excellent thermal insulation under wet or dry- con ditions. Zone 2 is also water resistant. ZONE 3 Unconsolidated GLLSULATE Earticles provide excellent thermal msuition and a high load carrying capacity. GILSULATE DISTRIBUTORS Ask for a demonstration of GILSUIATE'a unique properties COLORADO _ Joy sad Cox, Inc., tlM Broadway. . > COlfflECnCW ,, ,, A. P. Ine., P.0. Box 448, Stratiaid FLORIDA Gears* A. land, Jr., Jacksonville, . Tsffipe Manufacturer's Sales Co., . iRtfl No. Pace Blvd., Pensacola CEORCIA John A. Dodd Co.. 299 Techwood Drive, N.W., Atlanta ILLINOIS * E^g*.Industrial Co., Iso., 1021 N. 18th BL. E. St. Boy O. Kelson Company, S38 8. Wells St,, Chi cago 8 INDIANA Jackson Eamneering Co., Inc., PL Wayne, Indi- aaapotss. Lowell A Terre Haste - Allied Industries, Inc., 8717 Middle Bond, Davea- pvt A West Dee Moines KENTUCKY ' Jackson Engineering Co., Inc., 668 B Sth SL. Louisville 8 ' LOUISIANA Edcar Murray Supply Co.. Ine., P.O. Box 74, New Orleans 6 riwowc a X88S Ridgewood Ave., Baltimore IS MASSACHUSETTS ^ . _ Beaulieu end Munroe, 82 Crescent Avenue, Bos ton SS Mp^ICiidHiIrC..ANService |pdw4<i ,,ga,les _Co., _620 N. 108th PL, Milwaukee 18. Wis. . John P. Wolff Company, 788 Lothrop, Detroit 8 MINNESOTA _ Paid W. Abbott Co., Ine., TOi Vandsli* SL, 8L Paul 14 MISSOURI ' Andenoo.Stole Carp., 1737-83 Walmit SL, Ean- saa City 8 NEW JERSEY ,,, ,, A. P. Hinrichaen. Ine., 0 Ampere Parkway, Bast NEW YORK ' Axhley Equip"l Carp., Albany--Saratoga Rd.. Cohoes _. __ H. V. Boggs Co.. Ine., 419 E. Jeffcra SL, Sjrra- A.f! Hinrichaen, too., SO Church Street, New J. B. Magee Assoc., *49 Franklin SL, Buffalo S NORTH * SOUTU CAROLINA rvunto wuiu vjuuia , Lignite Combustion Engineering Corp., JU Airport Rd., Bismark, NJJ. OHIO William G. Jewett Co., 8697 Aurora Rd., Bolen Tbs Henry P. Thompson Co., Cincinnati A Co- OKLABOMA LoefBcr-Gncno Su 16M N. W. 8th, OREGON Winsor Co.. 80081 Marina View Drive S. W.. Beattie 68. Washington PENNSYLVANIA Holly Specialties Co., toe.. Walnut A 63rd Streets, Philadelphia 8 J F P---W Company. 3130 Market SL. Camp Hill _ Tutesn Equipment Co., P. O. Box 4451, Pitts burgh S TENNESSEE John M. Dooley A Awoe., 1833 M^aQs Ave., Knoxville ' Hurston-Conaway, Inc., 3470 Poplar Avenue, Memphis TEXAS _ _. . J. R. Dowdell A Co., Austin, Corpus Chnsti. Dallas, FL Worth, Houston, Lubbock, San Antonio Wltouns, Gritton A Wilde. 804 Dooly Bldg.. Salt Lake City VIBCINIA _,, , Sbults d James, Ine., 9 E. Cary E 19 WASHINGTON Winsor Co.. 80081 Manne View Dnve 8. Seattle 66 WISCONSIN ,, __ Building Service Industrial Sales Co.. 620 108th FL, Milwaukee 13 CANADA Engineering Specialtiee, *80 Richmond Road. Ottawa, Ontario Bkjp"*wriwg Equipment Co.. Lid., 874 Beanmoat Ave.. Montreal, Que. Insul-Mmstie Carpontku. Ltd.. , 1460 8pruce SL. Winnipeg, Manitoba Perry Produets Ltd.. _,, _ 586 Wat 6th Avenue, Vancouver 9, B. C- Michael Stuart Co-, Ltd.. IQS Egtinton Ave. E., Toronto. Ontario Insulation . 429 DURANT INSULATED PIPE COMPANY PALO ALTO, CALIFORNIA Durant Insulated Pipe Co., Inc. Williamstown, New Jersey DURANT Pre-Sealed INSULATED PIPE DURANT . manufactures pre-fabricated underground conduit systems to meet ALL federal and state specifications. DURANT pipe is suitable for steam, hot water, refrigerants, . _ process fluids, and for tracer type systems. DURANT - maintains complete manufacturing facilities on both the . East and West Coasts to render maximum delivery service at the roost favorable freight rate. DURANT representatives are at your service in the principal , cities of the U. S. and Canada. Fabricated in all standard sizes Manufacturers of conduit systems since 1934  430 Jherm-OiJi/z conduit FOR UNDERGROUND PIPING insulation CwnUuit um wLcrrouid H. W. Porter & Co., Inc. Newark 12, N. J. or Subsidiary REID HAYDEN, INC. Baltimore. Md. Charlotte. N. C. Richmond, Va. Thermo-O-Tile conduit is comprised of a vitrified tile envelope joined by cement mortar on a concrete base. It is designed to provide permanent protection of underground steam, high temperature or domestic hot water lines. Thermal efficiencies of 90 percent and higher are obtainable through the use of the proper commercial insulations. Therm-O-Tile cross section n*ing sectional pipe covering. Thenno-O-Tile offers other distinct advantages: I) Reasonable in cost; 2) Unusually strong--extra strength tile; 3) Accessible for piping re pairs; 4) Internal drain assures dry pipe area. . Four simple steps are required in the installation of Thermo-O-Tile: . a. Concrete Base. The concrete base is poured directly on the trench bottom and provides a permanent foundation for the piping and con duit. .. b. Piping and Supports. The piping is installed on factory assembled pipe supports which have been placed on the concrete base. c. Insolation. The piping may be insulated separately with sectional pipe covering or with compacted inorganic filler, as approved by H. W. Porter & Co. d. Tiles. The tile sections are manufactured from selected clays which have been salt glazed and vitrified. The base tiles are made from 4 in. to 12 in. high in 2 in. increments, and are 18 in. long. The arch tiles are made 9 in. to 30 in. in diameter in 3 in. increments, and 3 ft in length. For complete specifications, ask for Bulletin 9156. - LOAD BEARING COMPARISON TABLE Diameter Six* Pounds per linear foot. Sand Bearing Method, Pittsburgh Testing Lao Thenn-Q-TtJe . Avenge strength, minimum pounds per linear loot. Sand Bearing method. ASTU Specifications Standard Strength Qay Extra Strength Clay - Sewer Pipe. . Sewer ripe ASTM: C U-S7T ASTM: C JOO-57T 18' 21' 24' 4400 5200 6000 6700 - 2625 3000 3300 3600 4125 4950 5775 6600 Cross-section showing Therm -O-Tile . features Expansion loops are formed of standard Therm-O-Tilc parts. ' Oversized arch tile may be used if necessary to 'provide for expansion of pipes. -OVERSIZE TILE WHEN NECESSARY ni i J--H3 insulation * C.iwfutl vad Underground Ric-wiL Incorporated 431 Barberton, Ohio Prefabricated Insulated Piping Systems Underground and Overhead Representatives in Principal Cities This prefabrication technique produces units of exceptionally high thermal effi ciency and durability. Because of their inherent strength ana flexibility, they can be installed in shallow, narrow trenches --even aaderhighways andraiLroadtracks. Shipped in 21 or 41 -foot lengths with odd lengths and accessories as required, they are easy to handle and easy to install with a mihininm of field WOfk. HEL-COR* INSULATED PIPE UNITS 1. Steam, hot water, oil or refrigeration pipes 2. Insulation 3. Asbestos-felt jacket--asphalt saturated ' 4. Air space 5. Hel-cor conduit 6. High temperature asphalt coating 7. Asbestos felt--asphalt saturated 8. Welded collar , C*Hordpoeraartitono rtgtsl-tfe. d Tn^Msili of Araco Steel Ric-wiL Hel-cor Insulated Pipe Units are factory prefabricated tomeetspecifications for insulating and protecting single pipe or any combination of multiple pipes-- for steam, hot water, oil, other viscous fluids, process liquids and refrigeration . * lines. Pipes may be of any conventional material and pipe joints made as required. TYPE Ul UNILINE .INSULATED PIPE UNITS In this type of Ric-wiL Insulated Pipe Unit pipes are nested inside an insulation liner so that they are insulated from the exterior but not from each other. Any desired temperature can thus be main tained in system with tracer lines for steam, hot water, brine or any other heat ing or cooling medium, liquid or gas. Unilioe Insulation Liner is of highly effi cient insulating material, in any specified thickness, fitted to inside diameter ofcon duit. Individual pipes may be insulated if required. Insulation may be Ric-wiL Sectional Fibers glas insulation which has a lower K factor chan most other insulations now on the market. Return lines or other pipes not requiring insulation can be left bare. . Pipe and insulation, covered with a jacket of asbestos roofing felt, are housed in exceptionally strong, load-carrying, Hel- cor conduit--16 gauge, helically com*. . gated steel ofhill welded construction,hot dipped galvanized. The conduit is given two heavy applications of high tempera- . ture asphalt, forming a thick reinforced asphaltic coating to assure maximum pro tection against corrosive elements. TYPE J INSULATED For overhead piping, asphalt coatings and JACKETED PIPE UNITS? felt wrappings are omitted. Heavier gauge spiral weld conduits are available. Ric-wiL Insulated Jacketed Pipe Units are designed so that desired temperatures can Sturdy pipe supports, spaced according to be maintained in the system, with either requirements, carrying the weight of the pipe carrying the process liquid while the E*pe and assuring properalignment, while other carries the temperature controlling ring the pipe free to expand and con tract in the conduit without injury to the medium. Outer pipe is covered with inso lation as specified in any desired thick insulation. ness, covered by asbestos roofing felt 10 jacket. Firm supporting fins are welded to -gauge steel collars are welded to the- ' the inner pipe only, providing free move ends of the conduit. ' mentofpipes independently ofeach ocher. TEMPERATURE UNITS Ric-wiL Insulated Pipe Units with Low Temperature insulation are highly efficient for either single or multiple pipe distribu tion systems carrying brine, ammonia, freon, ice water, and other low-tempera ture liquids or gases. Low Temperature insulatioo in any specified thickness is given a heavy coating of asphalt and a ten sion wrap of asbestos felt to form a mois ture barrier before it is inserted in conduit when moisture barrier is required. Low Temperature insulation may also be used for Insulated Jacketed Pipe Units. INSULATED PIPE UNITS Ric-wiL Cast Iron Units provide a heavyduty outside bousing for insulated pipe lines buried underground--specificallyde signed to afford protection from corrosion and moisture infiltration. Mechanicallysealed joints provide ease of installation. It is an ideal system for steam or hot water lines for heating purposes, oil lines, serv ice lines for railroad yards^ and insulated piping for handling viscous fluids, chem icals, and refrigerants in various manufac turing and process industries. Cast Iron Units with pipe, insulating mate rial and conduit as per individual project specifications and requirements, are com pletely assembled at the factory and deliv ered to job site in approximately 18Vi Ft. lengths, with pipe at each end extending 3' beyond insulation and conduit. Three different methods are provided for making joint closures. Solid Sleeve--The best flexibility and the easiest to install. Standard Mechanical Joint--Good flexability, lower in material cost but usually more time required to insralL^ Flanged--May also be furnished. - Conduit diameters are available in all commercial sizes ofCast iron Pipe, allow ing a wide range of pipe sizes and insula tion thicknesses for any temperature or fpressure conditions, Ric-wiL Cast Iron nsulated Pipe Unit systems are complete, with all accessory units and fittings pre fabricated and insulated to conform with straight length units to make a finished piping system. Including housed expan sion devices. UTILIDOR CONDUITS Meet all service tunnel requirements of industrial plants, railroads, municipali ties, institutions, etc. Wide range of con-' duit diameters 36' through 84.  432 Insulation G. S. ZIEGLER & COMPANY Great Neck, New York FOR HOT UNDERGROUND PIPES Representatives throughout the United States and Canada Tri-Sui-Ite is a specially selected pure gilsonite used for protecting hot underground pipes against water, corrosion and heat loss. After being poured around and under the pipes and tamped, Tri-Sui-Ite forms, by proper curing, 3 efficient zones of protection. Curing is accomplished by transmitting heat through the pipes. ZONE 1 PROTECTION Permanent Water Barrier--The first zone of Tri-SuiIte, adjacent to the pipe, fuses from pipe heat into an impermeable, waterproof, corrosion-proof coating. It resists normal soil acids and alkalis. The first zone of Tri-Sui-Ite gives positive assurance that water can not follow the grade of the pipe. ZONE 2 PROTECTION Excellent Insulator--The second zone of partially fused Tri-Sui-Ite is a highly effective insulator which minimizes heat losses. ZONE 3 PROTECTION Insulator and Water-Barrier--The third zone of un fused Tri-Sui-Ite granules adjacent to the soil, pro vides maximum insulating efficiency, high resistance to water penetration and protection against surface shocks and subsoil stresses. Water cannot follow the grade of the pipe Excellent corrosion protection High insulating value ` Minimum capital investment Adaptable to wide range of multiple piping ar rangements . Very simple to install Cushions shocks and stresses Pipe maintenance practically eliminated TYPES OF TRl-SUL-ITE AND PIPE TEMPERATURE RANGES Type I Type II Type III 220 F to 300 F 300 F to 385 F 386 F to 520 F COMES READY TO INSTALL Tri-Sui-Ite arrives at the job site ready to install. No special mixing or preparation of the material is re quired. It is supplied in 100-lb cu ft) black and silver multiwall bags. FUTURE PIPING CHANGES SIMPLE Should branch lines or additions to the piping system be necessary, it is a relatively simple matter to open the trench, expose the piping, perform the necessary work and obtain quality protection with-Tri-Sui-Ite as in the original-installation. Cloee-up photo illustrates the plastic zone of Tri-Sol-Ite peeled back to show excellent adhesion for pipe protection TECHNICAL SERVICEFIELD SUPERVISION Trained men are available to cooperate with the engineer in adapting Tri-Sui-Ite to the piping sys tem. Supervision is available for installations provid ing it is arranged in advance. Insulation Diet 433 GENERAL SOUND CONTROL INC. engineered noise control equipment 6711 S. Sepulveda Blvd. --Los Angeles 45, California--ORegon 8-3724 AD8-2342 ACOUSTl-DUCT AD STANDARD SERIES ' 8 LENGTH IN FEET -2342 DUCT SIZE IN INCHES ADS-918 ACOUSTl-DUCT SAMPLE SPECIFICATION Noise'within all duct work shall be controlled by installation of Acousti-Duct units as manufactured by General Sound Con trol, Inc., 6711 South Sepulveda Boulevard, Los Angeles 45, California. Appropriate series and model of Acousti-Duct shall be used in accordance with the drawings. Construction of the Acousti-Duct shall be No. 22 gage or heavier sheet steel, and shall'be constructed to allow straight through airflow. Smooth aerodynamically contoured sheet metal transition sections shall be built into inlet aod outlet ends of each Acousti-Duct to flow air smoothly from the entire cross section of the unit into, the sound absorbent tubes. All sound absorbent material shall be faced with perforated sheet metal of not less than No. 22 gage. Acousti-Ducts shall be provided with standard 1 in. flanges at each end for connection to the duct system, or they may be provided with other standard forms of duct jointing when specifically called for on the drawings. ' The contractor shall furnish and install transition sections at inlet and outlet ends of each Acousti-Duct to the adjoining ducts whenever their cross section is different from the AcoustiDuct. Noise reduction in each frequency band shall be not less than is specified in Acousti-Duct Bulletin SOS by General Sound Control, Inc. .Pressure drop through each Acousti-Duct shkll not exceed values specified in Acousti-Duct Bulletin tOS by General Sound Control, Inc. ACOUSTI-DUCT Are complete ECONOMICAL duet ' silencer units ready, to install in heating, ' ventilating, and air conditioning sys tems. Are ENGINEERED to provide . . straight through air flow with aerody namically formed sheet metal entrance ' and exit sections for minimum pressure drop. May be selected by length to provide any required amount of SOUND RE DUCTION. Are available in STANDARD SIZES . from small to large duct sizes and from 2 to 10 feet in length. May be easily selected from BULLE TIN 205 which provides complete engjneering data. Send for Bulletin 205. Additional information and technical data may be obtained by writingto:Mr. Richard S. Dryden, % General Sound Con trol, Inc., 6711 S. Sepulveda Blvd., Los Angeles 45, Calif. -Aoougn -Txjcn~  434 insulation GUSTIN-BACON MANUFACTURING COMPANY 206 W. 10th St. Kansas City, Mo. Distributors in All Principal Cities (Consult Classified Phone Directory) G-B Snap* On Pipe Insulation Ultralite Duct Insulation (Thermal) Ultralite Duct Liner (Acoustical and Thermal) G-B Duct G-B Snap* On Pipe Insulation A one-piece molded pipe insulation of fine glass fibers for heated and chilled piping. "K" factor is truly exceptional-^-0.23 at 100 deg mean. The insulation is feather-light. .. flexible and resilient . . . insoluble in water . . . easy to cut with a knife . . . won't break or crumble . . dustfree . . clean and pleas ant to handle . .. available with canvas, vapor barrier, or roofing felt jackets. Snaps quickly on pipe. Single seam can be closed with any standard fastening means. Available in 6-ft and 3-ft long, single-piece sections, sizes H in.-36 in. and copper tubing sues to 6 in. See Sweet's Architectural File or wnte for Bulletin SO. ' Ultralite Duct Insulation (Thermal) A highly efficient "wrap-on" type thermal insulation weighing only 1 os per board foot in the popular % Ib/cu ft density. Available plain or with your choice of a number of facings already adhered to insulation (when a vapor barrier and/or a base for finished appearance on duct runs is required). Shipped in compressed rolls. (Write for AIA File S7-D-S) Characteristics of Ultralite. Ultralite Duct Insulation and Ultralite Duct Liner are composed of long, fine, textile-type glass fibers, bonded with a thermo-setting resin. Both are manufactured by a patented process and shipped in blanket like rolls. Both are immune to fire, rot, corrosion, age, rodents and insects; odors, vibration, and are low in moisture absorp tion. Ultralite is resilient--quickly returns to original dimen sions if compressed. ' Application Characteristics. Ultralite Duct Insulation and Ultralite Duct Liner are exceptionally light in weight. Can be cut readily with a knife, quickly run around curves and corners without special fitting. Can be adhered with adhesives, metal screws ana washers, even staples. Ultralite is not un pleasant to handle. Extreme simplicity of application keeps applied costs down. Ultralite Duct Liner (Acoustical and Thermal) A sound-absorbing insulation to be applied to interior of duct. Effectively absorbs objectional fan, air-rush and transmitted noises. Also an excellent thermal insulation. 3 types to cover full velocity range up to 7500 fpm. Won't break, chip or dent. Available in in., in. ana 1 in. thicknesses, coated one' ' side with a fire resistant coating. Can be adhered to flat metal sheets and fabricated with the metal through brakes and shears. A new coaling is available which complies with nil provisions of NBFU Bulletin 90-A. Carnes Under writers' label with flame spread classification less than 25. (Write for AIA File 37-DS) _. G-B Duct New prefabricated glass fiber for residential heating and air conditioning. Made of glass fibers and encased in an air-tight plastic vapor barrier. Hence, thermal insulation, sound ab sorber ana vapor barrier are built-in. Comes in 6-foot sectionin 4 in., 5 in., 6 in., 7 in., 8 in., 9 in., 10 in., 12 in., 14 in., 16 in. and 18 in. sizes. Approved for use in FHA insured homes. Tested by Underwriters Laboratories and now under label service. Pipe Couplings and Fittings Write for descriptive literature on G-B's complete line of couplings and fittings for plaiD end and grooved pipe. - . elof Hflnsson.inc. Acoustical Division, 711 THIRD AVENUE, NEW YORK 17, N.Y. 435 For AIR CONDITIONING and VENTILATING SYSTEMS UNLSILENCER* MODEL A Moderate pressure drop, standard acoustical efficiency A full line of Elof Hansson silenc ers to effectively reduce airborne noise generated by fans in air con ditioning, ventilating systems and by power roof ventilators. They are easily and conveniently installed in building structures at* low- cost due to new mass-production methods made possible by standardizing on modular sizes. Savings are of 'such proportions that UNI-SI LENCER* prices compare favor ably with conventional duct lining. The performance of UNI-SILENC ERS,* both as to acoustical attenu ation and pressure loss have been tested and certified by independent, impartial outstanding authority. The certified data are guaranteed in writing and bonded. Free engineer ing service! Distributors in ail major cities. UNI-SILENCER* MODEL LPD Lowest possible pressure drop, moderate acoustical efficiency UNI-RESONATOR* . Low frequency duct silencer--used in series with UNI-SILENCERS* . UNI-SILENCER* MODEL B Higher pressure drop, maximum acoustical efficiency T. 0. SILENCER Elbow silencer for ducts " 1 R. U. S. Pet. Off.  436 Insulation sa INDUSTRIAL ACOUSTICS COMPANY, INC 341 Jackson Avenue New York 54, N. Y. SPECIALISTS IN NOISE AND PULSATION CONTROL Manufacturers of Engineered Acoustical Products for Industry Quiet-DUCT Silencers STANDARDIZED "PACKAGE" SILENCERS . for SOUND CONTROL of AIRFLOW Quiet-DUCT Silencers 200 standard sizes Quiet-DUCT Silencers are engineered units having proven acoustical and air flow performance in the silencing of heating, ventilating and air conditioning systems. Easily fitted into existing sys tems, or in the design stage of new proj ects, Quiet-DUCTS Silencers provide the following advantages: 1. Quiet-DUCT Silencers measuring in length from 2 to 10 feet will give as much attenuation as a conventional lined duct measuring from 30 to 200 ft long, de pending on the frequency involved. 2. Quiet-DUCT Silencers eliminate empirical formulae and coefficient "guesstimates" out of the acoustic design of air-conditioning, heating and ventilating systems as all attenuation data has been determined by actual tests is our laboratories and verified by inde pendent laboratories. 3. Air-flow vs pressure drop data has alan been determined in our laboratories and verified by independent laboratory "MOD-U-SIZE" Quiet-DUCT Silencers 3 economical sizes Full Size I Half Size | Quarter Size 24 x 24 | 12x24 | 12x12 "MOD-U-SIZE" Quiet-DUCT Silencers are availabe in three stock production sizes; Full Size--24 in. x 24 in. x 30 in.; Half Size--12 in. x 24 in. x 30 in.; Quarter Size--12 in. x 12 in. x 30 in.: These MODU-SIZE Quiet-DUCT Silencers actually cast 20 percent less than other silencers, an economy made possible by produc tion-line volume of popular sizes carried in stock. MOD-U-SIZE Quiet-DUCT Silencers achieve further economies by reducing handling and installation costs. They nun easily be "built-up" in parallel or in series to meet any capacity and/or acoustic requirement. Their smaller "Module" size enables them to be easily taken through existing doorways, etc. MOD-U-SIZE Quiet-DUCT Silencers are certified for air-flow vg pressure drop, as well as acoustic performance by tests from recognized independent labora tories. Conic-FLOW Quiet-DUCT Silencers 100 standard sizes "CONIC-FLOW" Quiet-DUCT Silen cers are designed especially for axial flow fans and the higher pressure systems. CONIC-FLOW Quiet-DUCT Silencers are available in from 4 to 10 ft lengths and provides the attenuation achieved with 30 to 200 ft of lined ductl Engi neered and manufactured to a special for exceptional attenuation, Conic-Flow Quiet-DUCT Silencers can be used on high pressures. They are also used on lower pressure systems. They are especially applicable on jobs having high acoustic sound pressure levels. Selecting Quiet-DUCT silencers Complete technical data; attenuation, airflow vs pressure drop, and sizing, is available in the new Quiet-DUCT Silencer catalogs- Will be sent upon request. Quiet-VENT Silencers Quiet-VENT Silencers are special size Quiet-DUCT Silencers for installation on doors and in walls of air-conditioning and ventilating systems! These unique silencers prevent the passage of sound in either direction, yet permit the free circulation of air. Quiet-vENT Silencers are designed to fit* snugly inside walls or to "hug the wall", and are available in depths of 3M in-, 5 in. and 7 in.; and in widths of 30 in. and 42 in.; to handle 260 to 1710 cfm each. Used in offices, factories, apartments, homes, etc. QUIET-FLOW Cooling Tower Silencers Noise from Cooling Towers is controlled by "Quiet-FLOW" Silencers using special acoustic panels (and adjustable Resonators when necessary.) QuietFLOW Silencers for Cooling Towers are designed to assure proper attenuation of both intake and/or discharge. They are designed for minimum pressure drop to meet specifications. FAN PLENUM ABSORPTION PANELS & SPLITTERS Standard interchangeable acoustic pan els & splitters available for hundreds of noise control applications! Available in many sizes and thicknesses, Including panels with built-in resonators. Can be used to construct sound-proof enclo sures, noisy machinery enclosures, shop offices, fan plenum absorbers, etc. All parts interlock and may be removed and reused again and again. Technical Data regarding all phases of Noise Control is available by writing Industrial Acoustics Company, Inc-, Air Conditioning Department. Insulation KOPPERS COMPANY, INC. METAL PRODUCTS DIVISION Sound Control Department Baltimore 3, Maryland 437 SOUND TRAPS FOR ALL AIR HANDLING SYSTEMS This combination of acoustical structures in a single assembly is a unique and patented feature of Aircoustat. (IAS. Pat. Nos. 27S9SS4-T7S9SS6) Aircoustat sound traps are a fully effective means of silencing air conditioning" and air handling system noises of all frequencies in the audio frequency range. They have been thoroughly laboratory and field tested and proved in thousands of installations throughout the United. States and Canada. The units are simple to select and easy to install and no maintenance is ever required. All Aircoustat cases and angles are constructed of IS gage galvanized steel, assuring a structurally rigid, internally braced package- All units are internally damped to prevent noise leakage. All welds are con tinuous and all seams are mastic-sealed and guaranteed to be airtight when operating under an internal pressure of 8 in. of water. All acoustical materials are retained by a sheet of bonded matting plus a perforated galva nized face sheet. Units are rated as Class "A" fire re sistant. Two inch metal extensions are standard on all units for making quick, easy, airtight connections to ductwork. Aircoustat* are available in over 60 models, with cross section sizes ranging from 6 in. x 14 in. to 36 in. x 28 in. Larger cross sections are achieved by assembling these small units into one large unit right at the job site, making it possible to accommodate un limited airflow requirements and avoiding the necessity^ of handling lengths to meet all noise reduction criteria*. All Aircoustat pressure loss and noise reduction values have been verified by qualified and independent laboratories--the United States Testing Company, Inc. and Bolt, Beranek and Newman, Inc., Acoustical Consultants. In every case, all acoustical and airflow data are clearly defined to the satisfaction of the archi tect and consulting engineer. ' * See page 335 of this edition for further information and tables. For Complete Information, Data Books and Other Free Literature, Contact: SOUND CONTROL DEPARTMENT, KOPPERS COMPANY, INC., 201 SCOTT STREET, BALTIMORE 3, MARYLAND  438 Insulation * Ds* L O F GLASS FIBERS COMPANY Dept. 19-118, 1810 Madison Ave., Toledo 1, Ohio L-O-F GLASS FIBEKS' DUCT INSULATIONS LIGHTWEIGHT, FLEXIBLE, EFFICIENT Properties: Made from fine, consistently uniform glass fibers bonded together in blanket form, L-0*F Glass Fibers' Duct Insulations resist the transfer of heat. They also resist fire, settling and the effects of humidity. Glam fibers are inorganic. They provide no sustenance for fungi, bacteria, rodents or insects. Application: Lightweight, flexible and resilient, L*0-F Glass Fibers' Duct Insulations are easy to handle in large sections, easy to fasten securely by standard methods. They can be cut quickly with knife or shears; bent around curved surfaces; easily fitted into irregular areas. DUCT LINERS .Microtek Duct Liner effectively reduces mechanical noises, especially in the 250 to 4,000 cps range where most air-conditioning and heating system noises occur; . retards heat transfer through duct walls. When lined with Microtex, the metal of the duct acts as a vapor , barrier. Product Data: Microtex is a semi-rigid, lightweight insulation made from fine glass fibers, reinforced with glass textile yam, and bonded with a thermosetting resin. Also available: L 0 F Glass Fibers' Microlite and Super-Fine Duct Liner, non-rigid blankets made from extremely long, fine glass fibers without yam reinforcement. Noise Reduction Coefficient: Microtex-Liner 1 in. thick has a coefficient of 0.70 in 1 Yt Ib/cu ft density; 0.74 in 2 lb density and 0.75 in 3 lb density. No. 6 mounting used. Packaging Data: Microtex Liner comes in densities of 1 Yt, 2 and 3 lb/cu ft. Widths--36 in. and 48 in. ' Thicknesses--I in. and 1 Yi in. Lengths--in rolls, 60 or 100 ft. Coating: Duct Liners are coated on one side with black vinyl to resist air erosion even at peak operating velocities. DUCT WRAPS These low-density, resilient glass fiber insulating ma terials have high thermal efficiency and sound-absorp tion characteristics. Countless tiny air cells formed by -millions of fine glass fibers effectively minimise heat loss or gain. Product Data: Duct Wraps are available under the trade names Microlite, Super-Fine and Microtex. Microlite and Super-Fine are non-rigid blankets formed of extremely long, fine glass fibers. Microtex is a semi-rigid blanket of fine glass fibers, reinforced with glass textile yam. Thermal Performance: At 75 F mean temperature, Microlite or Super'Fine Duct Wrap of 1 lb/cu ft density has a k-factor of 0.24 (Microtex Va lb/cu ft density 0.29). Packaging Data: Densities--Vi, 1 lb/cu ft (Microtex Va lb/cii ft). Width--18, 24, 36, 48 and 72 in. Thick nesses--1 in. and 2 in. Lengths--in rolls to 200 ft, 'depending on thickness and density desired. Facings: All Duct Wraps are available plain, or with vapor-barrier facings such as reinforced paper and foil, vinyl film or aluminum foil applied. Where re quired, standard widths may have a 2 in. sealing tab on one or both sides. . Microtex Duct Liner is an efficient aeonstical and thermal . insolation for air-snppfy daces. Lining is attached to flat metal sheets with adhesive or mechanical clips; then formed in the brake with the metaL ' * L-O-F Glass Fibers* Duet Wraps eon be fitted quickly around duet and suporting hangers. Light-gage wire lira complete the job. Workmen find these insolations soft and flexible; pleasant to handle without gloves. Pi*. 439 L O F GLASS FIBERS COMPANY SALES OFFICES: Atlanta, Baton Rouge, Boston, Charlotte, Chicago, Cincinnati, Cleveland, Dallas, Detroit, Houston, Jacksonville. Kansas City, Mo., Los Angeles, Milwaukee, New York, Philadelphia, Richmond, St. Louis, Syracuse, Toledo, Washington, D. C. DISTRIBUTORS; (Located in principal cities) L-O-F GLASS FIBERS' MICRO-LoK PIPE INSULATION MICRO-LoK* a resilient one-piece, molded gla fiber PIPE INSULATION with full-length "SpringHinge" action. Description: Micro-LoK Pipe Insulation is made from long and fine glass fibers molded together into one-piece, three-foot sections for use in all standard iron pipe and copper .tubing. Temperature limit is 350 F maximum down to --120 F. Primary uses are cold and hot water supply lines; heating supply and return lines, either steam or hot water; dual temperature lines; and chilled water, brine, refrigerant and special process piping. Properties: Density--3.50 lb nominal. Moisture ab sorption--less than 0.2 per cent by volume. Alkalinity --less than 2 percent expressed as Na*0. Corrosivity-- (with steel, copper, aluminum) does not cause or ac celerate. Specific Heat--0.20 Btu/lb/F. Thermal Diffusivity--@ 150F mean temperature 0.032 sq ft/hr. .Micro-LoK is lightweight--a 3 ft section of 1 in. thick for fitting a 2 in. pipe weighs Ya lb L.F. It does not break or crumble during shipment or application. Glass fibers are incombustible ... resistant to moisture ... and will not rot, shrink or swell, , Application: Micro-LoK features an automatic "Spring-Hinge" opening and closing action that works like this: : Opens. easily Each section has a longitudinal cut completely through one wall and partially through on the other. Thermal Conductivity: 0 100 200 300 Mean Temperature, Degree F. Shaded area represents normal variation in conductivity due to manufacturing and raw material tolerances and to differences in testing equipment. Black curve shows average values and b osed for heat low calculations. Jackets: Available in canvas, weather resistant, or.a variety of vapor barrier jackets, such as general pur pose, dual temperature and flame resistant. All jackets factory applied with a minimum 1 Yt" longitudinal lap. Closes Automatically ` Locking action produces snug closure to insure minimum heat loss or gain. The fiber lay-up of Micro-LoK permits easy cutting _ and fitting of the inside diameter to conform to ir-y regularities common in pipe line systems, such as couplings, unions, etc. No tools--other than an ordi nary knife or shears--are needed. . Packaging Data: Available in all standard wall thick nesses--especially Yt in. and Va in.--for all standard pipe and copper tubing sizes. Lengths--3 ft sections. Shipped in' corrugated cartons. . For more information and samples on Micro-LoK Pipe Insulation, write or call the nearest L'O'F Glass Fibers Company Sales Office, or Dept. 19-118, h-0`F- Glass Fibers Co., 1810 Madison Ave.,' Toledo 1, Ohio. * Pit. Pending o440 Insulation dm OWENS-CORNI N G Fiberglas OWENS - CORNING INSULATION SELECTION GUIDE TOLEDO 1, OHIO Owens-Coming Fiberglas Corporation has long been a supplier of quality insmation products for the heating, ventilating and air conditioning industry. The selection guide Delow illustrates the broad range of products designed specifically for nearly every mechanical equipment insulation requirement. Addi tional information ana complete product specifications are available from any Owens-Coming Fiberglas Corporation branch office or authorized distributor. DUCT INSULATIONS TYPE USE facings factory-applied temperature Semirigid Flexible Semirigid Flexible TYPE PF Semirind board type duct insulations for ail types of heating, ventilating, air conditioning and dual-temperature duct systems. Available with a variety of facings for appearance and for func tional use. Plain (no facing) for heating ducts Coated for heating ducts Vapor barrier for cooling or dual-temper' ature ducts with asphalt adhered kraft paper (8F) or fire-retardant embossed FoD(FF) Resilient, flexible insulating blankets in Plain (no facing) for heating ducts rolls for insulating round and rectan gular duct work and fittings. Avail Vapor barriers: Aluminum foil 0.061 in.: able with a variety of facings for ap 0.002 in. thick; 0.004 in. grey vinyl pearance and for functional use. film; 30-30-30 duplex kraft: reinforced foil and kraft laminate. Joint flange overlaps furnished. DUCT LINERS Semirigid PF board type acoustical in sulation liner for absorbing duct system noise. One or both sides are coated to reduce air friction loss and bind surface fibers. Also insulates thermally. A sound-absorbent, mat-faced, flexible duct liner for rectangular or round duct systems. The smooth mat-faced surface reduces air flow resistance to a minimum and virtually eliminates the nrwsibilitv of fiber air erosion. Fire-retardant Neoprene coating ' Glass mat facing bonded to insulation PIPE INSULATIONS USE JACKET With a variety of factory-applied jackets thin universally used pipe insulation insulates all types of pipe and tubing from subzero to 450 F. Universal Dual-Temperature Canvas Flame-Retardant Vapor Barrier .. Roofing Felt To 250 F To 250 F SF to 150 F FF to 250 F To 250 F To 250 F Velocities to 6000 fpm To 250 F OPERATING TEMPERATURE -120 F to 450 F O-C Flexible Tubing Insulation (ggS?" One-Piece l=> Kaylo A molded foamed plastic insulation for iron pipe and copper tubing cooling and heating lines, chilled water and refrigerant lines. One-piece is a new addition to the Fiberglas line of pipe coverings. It has multipurpose use for all types of pip ing, is lightweight and easy to apply. Kaylo pipe and block insulation is a hy drous calcium silicate insulating ma terial for heating lines and equipment operating at temperatures up to 1800 None Same as PF Canvas--Standard Weight 6 and 8 oz equipment INSULATIONS TYPE TYPE USE FACING Fiberglas PF equipment insulation is a highly versatile and efficient insulat ing material. Made in a wide range of thicknesses and densities to meet most requirements. Heating and cool ing equipment Field-Applied 0 to 200 F -30 F to 400 F Standard K&ylo Up to 1200 F Kayio-20 Up to 1800 P . OPERATING TEMPERATURE Up to 400 F Fiberglas metal mesh blankets are made with unbonded fibrous glass faced on one or both rides with wire mesh or metal lath. They conform readily to ir Metal Mesh Blankets regular shapes. Heating equipment insulation Available with a variety of meshor lath facings to receive surface finish. Up to 1000 F Insulation cu Buk* OWENS-ILLINOIS General Offices. Toledo 1, Ohio GLASS BLOCK AND TOPLITE PANELS . TWO (I) PRODUCTS . $_ 441 CLASS BLOCK PANELS. Owens-Illinois Glass Block ate SOLAR HEAT GAIN. Complete instantaneous solar heat hollow, hermetically sealed glass units containing a % vacuum. gain data applicable to Owens-Illinois Glass Block designs for They are laid in mortar to form light-transmitting panels in , all exposures are given on Pages 190 through 194 of this Guide. vertical walls. Owens-Illinois Glass Block provide quality- The O-I design numbers which compare with the ASHAE type controlled d&yVighting by glass areas which reduce heat loss, numbers are as follows:-- surface condensation and infiltration in cold weather and heat gain in warm weather- ASHAE Type No. A Block Deafen Nm. TOPLITE PANELS. Owens-Illinois Toplite Panels are made of hollow, partially evacuated and hermetically sealed glass units, prefabricated at the factory into panels of insulated aluminum-grid construction. Used horizontally in roofs, Top II III IV A V 307, 316, 330, 331, 370 340 340 with Fiberglas Insert 365 363 lite Panels offer controlled dayligbting with reduced beat loss, surface condensation and solar heat gain. --' New O-I glass block designs #80 solar-selecting and #80 solar- THERMAL INSULATION. The coefficients of heat trans selecting green are available. They have a lower solar heat mission 'U' for panels of O-I Glass Block and Toplite are as gain than any of those shown in THE GUIDE. These blocks follows: . have a variable rate of solar energy transmission depending SiM f EHeck 5% in. sq 7% in. sq 7% in. sq with Glass Fiber Insert* ft/hr/F Tins Difference) .60 .56 * .48 on sun altitude. When the solar energy is maximum on the exterior of the wall, the #80 glass blocks have a minimum transmission. Calculated values of solar heat gain for these blocks are now available. . 11% in. sq .52 11% in. sq Toplite Panels with Glass Fiber Insert 44 . .58 ' Solar heat gain through Toplite panels is much less that through single glass or plastic skylights, due to their solar- See page 123 in thin GUIDE.'for additional U Factors applicable to Owens-Illinois Glass Block. selecting characteristics. They act as a mirror in reflecting a high percentage of the Bolar energy when the sun is at high altitudes as in the spring and summer months. SURFACE CONDENSATION* Because of the low over-all, air-to-air heat transfer, the Exterior air temperatures which will produce condensation on panels of 0-1 Glass Block and Toplites are much lower than those for ordinary single glass. This permits higher humidities to be maintained where needed for winter air conditioning for comfort or for industrial proc- DESIGN AND SIZES. Owens-Illinois Glass Block are made in a variety of face designs and in three standard sizes (5% in. sq, 7% in. sq, and 11% in. sq--all three are 3% in. thick). Mortar joints oi % in. thickness are recommended. INFILTRATION. Panels of glass block which are laid in mor tar provide a barrier against infiltration. Dusts, drafts, and air and vapor leakage are minimized. Natural ventilation re quirements can be met by installing windows in glass block panels. Prefabricated Toplite Panels are available in seven standard sizes: 2 x 2, 3 x 3, 4 x 4, 2 x 6, 3 x 6, 4 x 5, 5 x 5.--all 7 are 3%# in. thick. Complete technical data, description and details will be gladly sent. Write: Kimble Glass Company, subsidiary of Owens-Illinois, Department HV, P. O. Box 1035, Toledo 1, Ohio. i  442 Insulation PITTSBURGH DEPT. S-9, ONE GATEWAY CENTER CORNING PITTSBURGH 22, PA. FOAMGLAS . . . the cellular, stay-dry insulation What FOAMGLAS is ... FOAMGLAS is a unique thermal insulation composed of closed cells of glass. It possesses a combination of physical characteristics which makes it virtually an ideal insulation. It is completely inorganic and thus will not bum, rot, swell or slump. Its closed cell structure renders it impervious not only to moisture but to moisture vapor as well. Because it is water and vapor proof, it retains a constant insulating value (k) for the life of an in stallation. In addition, FOAMGLAS doesn't require a costly separate vapor barrier. FOAMGLAS is unusually strong, having an average ultimate compressive strength of nearly 7 tons per square foot. But FOAMGLAS is light in weight, works easily with ordinary tools and therefore is very easily installed. All of these characteristics have enabled FOAMGLAS users to benefit from its constantly-high insulating performance. That's why FOAMGLAS has gained recognition as an excellent insulation for roofs, ceilings, walls, and floors of dll kinds of buildings as well as for hot, cold and dual temperature piping, tanks, and other equipment. For Building, Roofs, Ceilings, Walls and Floors. At Win* ston-Saiem, FOAMGLAS* high strength permitted insulating parking deck-roof of Sears Roebuck's air con ditioned store. In your building, moisture-proof FOAM GLAS insulation can help maintain air conditioning sys tem efficiency. HOW FOAMGLAS can benefit you: Absorption Properties 0 Combustibility Compressive Strength ItwvmihmtihU 100 Ibe/sq in. Hygroscopieity Density No increase in weight in MS days in tir it 00 percent relative humidity 0 tbe/cu (t (sve) ThermalCondue- 048 Bto/hr/sq fl/'F/ tivity (k)t50*Fl in. Benchts Moisture reduces insolation effec tiveness. li/e. FOAMGLAS stays dry, m;taming constant insulating value. Protects from fire baaards. Offers unusually high strength for varied structural and load bear ing applications. FOAMGLAS is its own vapor bar- Lightweight, easy to handle and install. Excellent insulating value that remains constant FOAMGLAS is approved by Underwriter*' Laboratories and is listed under Label Service. . For Piping. FOAMGLAS pipe insulation (available for up to 36 in. pipe size) was applied on this welded pipe currying cold water for the system air conditioning several new skyscrapers. For lull technical information, please write for our new catalop indicating which of the above uses of FOAMGLAS you are most interested in. Address Dept. S-9, Pittsburgh Corning Corporation, One Gateway Center, Pittsburgh 22, Pa. . ' ;l Insulation cu Pittsburgh Plate Glass Company FIBER GLASS DIVISION One Gateway Center Pittsburgh 22, Pennsylvania 443 Pittsburgh Superfine insulation is-composed of extremely fine glass fibers, ranging upward in diameter from only 3/100,000 of an inch. It's an exceptionally light-weight, efficient thermal and acoustical insulating material. When' . specifications call for control of heat or cold--or you need sound absorbed or deadened--here are some of the ad vantages Pittsburgh Superfine Fiber Glass insulation provide: . High Thermal Efficiency--Thermal conductivity, k, at a mean temperature of 75 F is 0.22 to 0.29 Btu (sq ft) (hr) (deg F) (in.) thickness, 'depending on density. Effective for both high and low temperatures ranging up to 500 F. Fine Acoustical Properties--Noise reduction co efficient of a 1 in. thickness is as high as 0.85 with the - sound absorption curve showing high efficiencies in the ranges of the most irritating noise. Light Weight, Easy to Handle--Added load in any application is virtually negligible. Readily cut with knife, shears, or die: Can easily be sewed and quilted, glued, tacked or taped into position. Flexible, Resilient, Tough, and Soft--Made from long, fine glass fibers to attain superior qualities. Can be used on round or irregularly shaped objects and spaces as easily as in conventional layers. Fits closely into comers and tight spots quickly and easily, without damage to its structure. Saves Vital Space--In use: Higher insulating effi ciency means less thickness of Superfine required, as compared to ordinary insulation. In shipment: Pack aged compressed to reduce shipping and storage space. STANDARD SPECIFICATIONS--Pittsburgh Super fine is available in standard roll widths of 18 in., 24 id., 36 in., 48 in., 54 in. and 72 in. It can be supplied in any desired width down to 2 in. Rolls are wound on 2 in. tubes and wrapped in heavy kraft paper. Super! furnished neoprene coated for *Duct Liner or with var is also available in special lengths on request. It is paper, cloth or foil facings.  444 (Armstrong COOK COMPANY Lancaster, Pennsylvania Insulation Insulation THE DOW CHEMICAL COMPANY s Plastics Sales, Midland, Michigan 8 445 ARMSTRONG ARMAFLEX PIPE INSULATION for all air-conditioning, refrigeration, and plumbing and heating lines Armstrong Armaflex is a flexible foamed plastic insulation in pipe covering and sheet form. Pipe covering is manufactured in nominal % in., X in., and % in. thicknesses. These thick nesses are calculated to prevent condensation on cold lines within their individual recommended usage ranges at temper? atures down to zero. Armaflex also can be used on heating lines, where it will withstand temperatures to 200 F. On out door installations, consideration should be given to weather proofing. In sheet form, Armaflex is used for insulation of larger pipe sites and for covering tanks and vessels of any site or shape. The closed cell structure of Armaflex gives it a low k value of 0.28 at 75* F. mean temperature. Armaflex resists deteriora tion, so efficiency remains high in service. The uniformly sited closed cells of Armaflex seal out air and moisture. The result is a vapor transmission rating of less than 0.1 perm. Shrinkage of Armaflex when the inner surface is exposed to temperatures to 200s F. is negligible. Armaflex is only slightly affected by solvents and for all practical purposes is unaffected by oils, common corrosive chemicals, or fungus. The extreme flexibility of Armaflex Pipe Covering and Sheets mokes application very rapid. They can be applied in close quarters. Pipe covering can be slipped onto pipe and tubing prior to its installation or slit and snapped over piping that is already in place. The only sundry material required is Arm strong 520 Adhesive. Scotch Brand #472 Tape may be used to seal Armaflex joints on straight piping. Fittings are insulated with miter cut pieces of covering, quickly cut and assembled on the job, using 520 Adhesive to adhere joints. Physical Properties of Armaflex Pipe Covering Wall thickness--inches (nom) Inside diameter--inches Length of section--feet Sheet Armaflex Site--inches Thickness--inches Thermal conductivity Btu-in./sq ft-hr-*F-kj, k| Water vapor transmission Perms (Grains-in./sq ft-hr-in.-Hg.) Air transmission--static pressure at 10 in. Hg. cu ft-in./hr-sq ft Water absorption--28 days submer sion--percent by volume Density--Ibs-cu ft Fire rating ' H.H.H H to3H 30x36 M, X, H, X, H,H less than 0.1 less than 0.03 3.9 pipe covering 7.5 sheets 6.5 self-extinguishing For complete application instructions and specifics* tiona, write today to Armstrong Cork Company, 5800 Preston Avenue, Lancaster, Pennsylvania. STYROFOAM STOPS MOISTURE, REPELS HEAT Advantages of Styrofoam* as a Low Temperature Pipe Covering . (1) Low "k" factor stays low because Styrofoam (a Dow Bending Modulus Modulus of Rigidity SI Styrofoam 22 1000-1285 700-1600 Styrofoam 33 1250-1760 1000-1300 plastic foam) resists water and water vapor. (2) Prevents condensation and dripping. (3) Light, clean, easy to handle, economical to apply. (4) Resists rot, mold, deterioration. WATER RESISTANCE PROPERTIES Capillarity None Water absorption (5) Will not split or crack nor is it subject to ice build-up around valves in extreme'cold. (When subjected to 90*F^ 90 Less than 0.03 per cent by per cent relative humidity for volume 15 days) i USES Pipe covering Wall, floor and ceiling insulation for low temper . ature work Cavity and core walls * Insulation-plaster base Refrigerated vehicles Curtain wall panels Perimeter mid Water absorption (When completely submerged Water pick-up only on sur- for one week) face cells less man 0.15 ' Ib./sq. ft of areas foundation insulation VAPOR TRANSMISSION ENGINEERING DATA THERMAL- PROPERTIES Thermal Conductivity (k factor), Btu/(hr) (sq ft) ("F/in.) Linear Thermal Coefficient of Expansion Specific Heat Resistance to Heat (Maximum recommended temperature for continuous use) Average less than 0.28 at mean temperature of 40*F, .00003 to .00004 in-/in.*F. between... 0*F.and 80*F. 0.27 Btu/(Ib.) (*F.) at 40*F. Styrofoam 22--170*F. Styrofoam 33--160*F. When Styrofoam acts as a barrier 1.0-2.0 grains/(sq ft) (hr) between spaces having different (in. thickness) (in. of Hg. atmospheric conditions vapor pressure difference) ' MANUFACTURERS Styrofomics, Ino, 17 Hawkins Street, Somerville, Mass. GloBrite Products Incorporated, 6415 North California Avenue, Chicago, Illinois TufSite, Inc., Ballston Spa, New York Styrp^ Fabricators, 1401 Fairfax Trafficway, Kansas City, Kansas Robinson Industries, 3051 Curtice Road, Coleman, Michigan * MMM, Incorporated, P.O. Box 968, Portsmouth, Ohio * Kennedy Industries, 4447 Alger Street, Los Angeles, California Fastab Insulation, Inc., 304 Cleveland Transit Building, Cleveland 14, PHYSICAL PROPERTIES Density (lb/cuft) Compressive Yield Strength (psi) Tensile Strength (psi) Shear Strength (psi) Flexural Strength (psi) Compressive Modulus (psi) Styrofoam 22 1.6-2.0 16-32 45-61 27-36 42-61 1200-1700 Styrofoam 33 1.7-2.3 16-38 65-95 30-40 48-99 1500-2000 Ohio * Fibrous Glass Products, Inc., Hicksville, L. I., New York Kransco Manufacturing Company, South San Francisco, California For further information on Styrofoam in any application write to the now mrMirti comfant. Midland, Michigan, Plastics Sales Department 1941R. We can 1<q give you information on Scorbom*, the new easy-tO-app!y member of the Styrofoam family specifically designed for perimeter and cavity wall applications. STYROFOAM oad SCORSORD ' traH--ioriu of TV* Dow Qtanwcol frmiinnj YOU CAN DEPEND ON  446 1,nutation . THE PHILIP CAREY MFG. COMPANY LOCKLAND, CINCINNATI 15, OHIO PRODUCTS and chemical properties. Alltemp retains its high thermal efficiency and structural strength even when subjected to long and continuous exposure to high temperatures and moisture: It is available in blocks 1)4 in., 2 in., 2)4 in., 3 in., 3J4 in. and 4 in. thick, measuring 6 in. and 12 in. wide and 36 in. long. ALLTEMP PIPE INSULATION Uses: Alltemp pipe covering is an all-purpose insulation for temperatures from 100 F to 1600 F. It has an extremely low thermal conductivity, low internal shrinkage, and exceptional moisture resistance. Alltemp is particularly recommended for irregular surfaces, and for use around valves and fittings where it can be applied in single-layer, or broken-joint double layer construction. .. Description: Alltemp is a combination of special inorganic silicas and asbestos fibres. Every cubic foot is honeycombed with millions of tiny sealed air cells. Having excellent physical and fhaiwicftl properties. Alltemp retains its high thermal efficiency and structural strength even when subjected to long and continuous exposure to high temperatures and moisture. Alltemp sectional pipe covering is available through 12 in.; tri-sections and quad-sections available in larger sixes. "Nest ing OD" pipe covering sizes provide accurate tight fits over or into another size. This permits a wide range of assemblies and gives the advantage of building up many thicknesses from a limited number of prime'units. FIREFOIL BOARD Uses: Carey Firefoil is recommended for insulated and acous tical duct construction in heating and air conditioning sys tems, industrial ovens, coil housings, plenum chambers, mariTM* bulkheads, etc. Firefoil is recommended for interior use and under dry conditions. .- Description: Firefoil Board is formed of laminated plies of corrugated and flat asbestos paper sheets, bonded with a special fire-resistant adhesive. Firefoil has approximately . eight corrugated layers per inch of thickness. It is chemically . treated and hardened to give it strength and resistance to both fire and water. Carey Firefoil is a most efficient and economical panel material for many industrial and building construction applications. Firefoil is recommended for use at temperatures up to 1000 F. Carey Firefoil is available in thicknesses from )4 in. to 3 in., in )4 in. multiples. Standard panel size is 48 in. by 96 in., but smaller sizes can be factory-cut to order. ALLTEMP BLOCK INSULATION Uses: Alltemp Block is recommended for high temperature surfaces such as oil stills, ovens, boiler walls, breechings, furnaces and other equipment whose surfaces are between 100 F and 1600 F. It has an extremely low thermal conductivity, low internal shrinkage, and exceptional moisture resistance. Alltemp Block is available for fiat and curved surfaces. It is particularly recommended for irregular surfaces which require an easy-to-apply insulation. ' Description: Alltemp is a combination of special inorganic eHjpp* and asbestos fibres. Every cubic foot is honeycombed with millions of tiny sealed air cells. Having excellent physical CAREY SPUN WOOL DUCT INSULATION . Uses: For insulating rectangular, metal ducts for ventilating, air-conditioning and cooling systems in schools, stores, office buildings, factories, apartments, etc., where non-combustible insulation is required. Description: Made in semi-rigid panels, processed from long, firm fibers of spun mineral wool. Panels are available faced with 0.0025 embossed aluminum foil, securely attached with non-flammable adhesive; coated for interior duct sound proofing or asphalt-kraft vapor barrier facing. Light in weight, with a density of approximately seven pounds per cu ft, this insulation is easy to work and handle, is quickly installed and provides a high degree of thermal efficiency. Foil faced duct insulation is non-corrosive and has been tested and approved by Underwriters Laboratories. Sheet size is 24 in. x 48 in. in 1 in., 1)4 in. and 2 in. thicknesses. Atr Doct* Ftp* THE PHILIP CAREY MFG. COMPANY LOCKLAND, CINCINNATI 15, OfflO 447 PRODUCTS THERMOGLASS PIPE COVERING Uses: Thermoglas pipe covering is used for pipe temperatures up to 350 F. It is recommended for hot water and low-tempera ' tore steam piping in industrial plants, commercial buildings and institutions. Thermoglas can be used as an outside layer over a high-temperature insulation. Description: Thermoglas pipe covering is used on pipes hav ing temperatures up to 350 F. It simply "snaps in place." Thermoglas is exceptionally lightweight insulation composed of long, fine, blown glass fibers bonded with thermal-setting phenolic resin. It is a strong, semi-rigid and resilient insulation with no coarse fibers to irritate hands or skin. Thermoglas is available in one-piece sections made in 3-ft lengths for small sizes. Medium and large sections are furnished in 6-ft lengths. Canvas white and black dual-temperature and roofing felt jackets are available. IMPERVO WOOL FELT PIPE COVERING Uses: Impervo is used primarily for insulating chilled water and ice water pipe lines operating at temperatures between 40 F and 60 F. It is specially designed to keep water cold and prevent condensation causing damage from dripping. Recom mended for cold service water piping under particularly high humidity conditions such ss in laundries, kitchens, bakeries, textile and paper mills. Description: Impervo is composed of multiple layers of insulating felt with water resistant felts on the inner and outer surface of each layer. It is furnished in sections three feet long with canvas jacket, for both iron and copper pipes from )i in: through 24 in., and is regularly made in Double )4 in. and Double 3.4 in. thickness. Other thicknesses can be made special to order. Four inch (4 in.) wide collars for sealing cad laps, as well as longitudinal flaps on outer water resistant felt will be furnished special on request. . SUPERBO PIPE COVERING Uses: Carey Superbo is a rigid dual temperature pipe insula tion for chilled water pipiQg or piping operating at alternating high and low temperature with a service range of from 35 F (lower limit) on the cooling cycle to 200 F (maximum) on the heating cycle. The integral vapor barrier jacket properly applied and sealed will protect chilled water lines from con densation or sweating. Thickness requirements vary with the pipe size and conditions of temperature and humidity. Where recommended thickness exceeds 1)4 in. and the pipe size is 6 in. and over, double thick Superbo construction and broken joint application is required. ' Description: Carey Superbo is a rigid pipe insulation made of multiple layers of "dry" insulating felt (wool felt) firmly cemented together. The inner surface is lined with asphalt saturated organic felt. A factory applied white vapor barrier jacket is furnished consisting of aluminum foil laminated be tween two layers of special creped Kraft paper, bonded with asphalt. This same vapor barrier jacket is also available with a black outer surface. 8uperbo is furnished with 4 in. wide collars of the same vapor barrier material as the jacket. PERFECTO WOOL FELT PIPE COVERING Uses: Perfecto is an efficient economical pipe insulation for temperatures between 60 F and 225, keeping hot water hot and cold water cold, and preventing sweating of cold water service lines. For service water temperatures between 45 F and 60 F, integral jackets with properly sealed joints give ade quate service for intermittent operation. For continuous operation a water vapor barrier integral jacket should be used. Perfecto is not designed for dual temperature systems. S' Description: Perfecto is a semi-rigid structure made of multi-' pie layers of indented "dry" insulating felt (wool felt) firmly cemented together. The inner surface is lined with asphalt- saturated organic felt. Carey Perfecto covering is furnished' with a white wrapper under the canvas. ' Perfecto is finished with 10.2-yards-per-pound cotton cloth jackets. Heavier canvas jackets can be furnished. Perfecto can be finished with roofing jackets, such as the Carey recom mended jacket of 45-lb Surety Roofing. Descriptive Bulletins and Catalog Pages on Carey Insulation Products are available at Carey District Offices. Application details and specifications can be obtained by writing IN SULATION DIVISION, The Philip Carey Mfg. Company, Plymouth Meeting, Pennsylvania. - '  448 B. F. Goodrich The B. F. Goodrich Company 574 Derby Place, Shelton, Conn. Insulation kucr B. E Goodrich Molded Cell-Tite* Tubing for moisture-proof insulation B. F. Goodrich Molded Cell-Tite tubing is made of tough, flexible rubber with uniform non-connecting cell structure. Especially efficient and con venient for pipe insulation, it will not absorb moisture nor support combustion. Insulation value is excellent. Easy application Wherever used, B. F. Goodrich Molded Cell-Tite may be easily secured with air-drying adhesive. Short lengths of tubing may be slipped on; longer ones rosy be slit lengthwise, snapped over pipe and adhesive ap plied to cut edges. These edges will not absorb mois ture. Low water absorption B. F. Goodrich Molded Cell-Tite meets ASTM speci fications. Weight gain is under 10 percent after 24 hours immersion in water; under 5 percent after 3 minutes additional atmospheric pressure. Efficient insulation Thermal conductivity of B. F. Goodrich Molded CellTite is 0.28 at 75F with no deterioration in service. Low shrinkage and aging B. F. Goodrich Molded Cell-Tite has no appreciable change after 7 days at 200F. Resistance to weather aging is good. Linear shrinkage, when aged 4 weeks at 158F is under 10 percent, most shrinkage occurring in the first week. ` Wide range of density and firmness Standard grades of B. F. Goodrich Molded Cell-Tite are ASTM 41 to 43 (from 5-13 psi to compress a one square inch disc to 75 percent of its height). Can be made in practically any firmness. Density varies, de pending upon size and firmness, averaging 10 lb per cu ft for soft, 15-20 lb per cu ft for medium, and 20-30 lb per cu ft for firm. Many sizes - B. F. Goodrich Molded Cell-Tite tubing is made with standard outside diameters of % in., 1 in., lVi in., iVt in., and can be made 1% in., 13A in., and 2 in. Almost any inside diameter is available up to Y\ in. of the out side diameter. Lengths up to 50 ft facilitate ease and simplicity of installation. Variety of colors Black is standard and can be furnished as non-stain ing to lacquer, enamel or plastic. (Tested for 24 hrs under ultra-violet light or for 10 days at 158F.) Any one color available for requirements of 7,500 ft or more. White, if specified, would be off-white. Please write for more information Insulation 449 HAGAN Mfg. Company, delphos, ohio Thermal and Acoustical CELLULOSE FIBER INSULATION PREFERRED BY MANY -24in the ELECTRIC HEATING INDUSTRY INSUL-FIBER BLOWING WOOL K-foctor = 0.24 Quality production control Only first-grade cellulose material used Pressure atomization process for consistent den sity and texture * Positive chemical control provides permanent protection Permanent fire resistance, ro dent and vermin resistant, harmless to handle Expels moisture Bonded material. BLANKETS K-factor = 0.24' * Light weight Resilient Moisture Resistant Vermin Resistant All std. sizes All std. moisture barrier configuration SIU PAD Designed for easy application around high heat loss window and door framing -- 4 50 ft rolls 6 in. wide to the carton. WHY IT IS USED insisted Sorties .0 Faster BLOWN MATERIAL Ceiling with 6' Ceiling with 4' Frame Walls with 3H- BATT MATERIAL Knee Walls with 3%" Double Wood Floor with 2" Double Wood Floor with 3' .038 .055 .059 .063 .088 .065 Faetsr .011 .016 .017 .018 .027 .019 These coefficients, from HAGAN products, provide LOWER ELECTRIC HEAT OP ERATING COSTS. Products proved in thousands of electri cally heated homes and com mercial buildings. HAGAN MODEL J BLOWER -- PORTABLE, 110 VOLT 1 HP. Tornado Blower motor, % HP. agitator motor, controlled air flow. ' Moves 25 bags per hour. Airtight shut-off nozzle. 20-yr. Hagan experience perfected this applicator package for cellulose material. Complete with hole saws, couplings, 75 ft hose, nozzle, etc. Package complete. All wiring properly protected from damage due to rough handling. Operating instruction manual included. RELATIVE HUMIDITY CONTROL SYSTEMS FOR IDEAL LIVING CLIMATE 1. Maintain safe, healthy humidity. 2. Prevent window (teaming. 3. Prevent winter mildew. 4. Prevent wall and ceiBng (wealing. 5. Prevent paint peeling caused by inside moisture. 6. Allow.the insulation to do a better jab by keep ing it dry. 7. The tan naturally expels cooking grease and holds dawn cleaning cost and effort, ` '  450 J OHN S-MANVILLE 22 East 40th Street, New York 16, N. Y. Office? in All Large Cities SPINTEX DUCT INSULATION J-M Spintex, a super-springy, spun fibre insulation, is an excellent insulation for air-conditioning ducts in offices, factories, institutions and commercial buildings of all kiods. Produced by a special Johns-Manville spuming process which assures complete uniformity, the fibres possess unusual fine ness. This improved fibrous structure adds countless heat blocking dead air spaces per cubic inch to help keep working temperatures precisely the same throughout the structure at lower operating cost. ,_ Spintex will not burn or let fire spread along duct systems. Ihe fibres are non-absorptive and treated to arrest capillary action, and will neither rot nor mildew. It is not corrosive to any common metal or building material- . . Spintex can be installed quickly and easily because it is light and "friendly" to handle--simple to cut and fit, even when ducts are curved or in difficult-to-reach areas. It is available in rigid, semi-rigid or flexible form. ... Spintex is regularly furnished in a variety of special facings to meet any vapor condition, incombustibility requirement or decorative need. It provides a good base for plaster finish ._. . or where no facing is indicated, Spintex presents an attractive appearance with trim, tidy joints. Insulation AIRACOUSTIC SHEETS J-M Airacoustic Sheets meet the exacting requirements of air duct sound conditioning. Since they absorb a large percentage of the Found that strikes them, they provide a highly effective means of reducing disturbing duct noises. Composed of mineral wool and a suitable binder, Airacoustic Sheets are completely non-combustible, highly sound-absorbent, moisture-repellent, odorless and vermin-proof. They are supplied 24 in. x36 in. in % in. and 1 in. thicknesses. SPINTEX HOME INSULATION J-M Spintex spun mineral fibre insulation is made by the revolutionary spinning process which produces finer fibres. Because of these finer fibres, Spintex has more beat-stopping dead air spaces per cubic inch. It is these dead air spaces and the thickness of the insulation which results in greater insulat ing efficiency. Spintex will not rot or decay ... is inherently fireproof. It will not sag or settle ... the firmly felted fibres have the resilience to maintain a tight fit between framing members. It assures year-round comfort, protection and savings in fuel and air conditioning costs. J-M 8pintex Batts and Blankets are fabricated in a variety of thicknesses to meet all requirements. They are light in weight, have greater rigidity and resilience for ease of handling and tight fit, cut clean and sharp for better, faster, labor-saving application..Each has-an efficient vapor barrier and is care fully manufactured to meet Federal Specification Blankets are available either Kraft paper-wrapped or alumi num-wrapped. J-M Spintex Home Insulation is also available in "blown" (nodulated) form for new and existing light construction. Details on Request - For details on J-M Spintex Home Insulation or the complete line of J-M Industrial Insulations, write Johns-Manville, insulation 451 JOHNS-MANVILLE 22 East 40th Street, New York 16, N. Y. Offices in All Large Cities JOHNS-MANVILLE INSULATIONS For Heating and Plumbing Service FIBROCEL PIPE INSULATION for service from 35F to 300F No Shrinkage The use of Fibrocel makes objectionable shrinkage negligible. It is pot affected by changing atmospheric conditions. Joints stay tight... no unsightly gaps with ac companying heat leakage or costly repairs. Firm, Strong Structure Fibrocel resists compression and abuse. It gives back-up protection against puncture of jacket or vapor seal- Its smooth hard surface takes abuse in rough service. High Thermal Effectiveness Tiny particles of silica are exploded and expanded to form a cellular structure of heat trapping dead air spaces. Permanent and Sanitary Fibrocel is impervious to flame, rot, odor and vennin attack. It will not disintegrate in water; original properties are restored after drying. Fibrocel is a molded silica insulation developed by JohnsManville for use on hot, cold and chilled water lines, low pressure steam pipes and dual service heating and cooling systems. Easy to Install Fibrocel is light and easy to handle, it readily cuts with a knife. Tight, snug-fitting edges provide better heat control, smooth appearance. Jacket Styles Type -VS--richly creped pure white kraft backed by ^ mil-foil. Type VB--outer surface has same rich creping, inner barrier is full mil thickness of aluminum foil; pipe facing is creped black kraft. Type C--canvas finish. AEROTUBE PIPE INSULATION for service from 32F to 200F Aerotube is a foamed plastic tubular insulation expressly recommended for heating, plumbing and air-conditioning service. Its closed cell structure acts as a "built-in vapor barrier" to stop the passage of moisture ... obviates the necessity of applying a separate vapor barrier. Its extreme flexibility and resiliency permit quick, easy application, especially on bent tubing and fittmgB. Aerotube is clean' odorless, durable . . . docs not carry flame and is self-ex tinguishing. Aerotube is furnished in 6 ft lengths in the following iron pipe and copper tubing sizes: % in. thick--^ in. through 2 in.; H io. thick--in- through 3 in. It is also available in sheet form for flat surfaces and equipment not adaptable to pipe insulation. J-M THERMOBESTOS For Service to 1200F Thermobestos is a calcium silicate in sulation developed for the most rugged industrial service. Strong and rigidit will withstand unusual service abuse! It offers maximum moisture-resistance and low thermal conductivity, will not bum or carry flame, and is light in weight for easy handling and fast application. Pipe insulation furnished in 3 ft sections .in nominal thicknesses of 1 in. (up to 6 in. pipe size only), 1^, 2, 2ti, 3 and 3X in: Block insulation in 38 in. lengths, 6 and 12 in. widths, 1 in. through 4 in. thicknesses. Other J-M Insulations Product Description Standard Sbes *J-M 85 percent MagPot service to 6007 Made from hydrated beak; carbonate of msgnesia bonded with aabeatoe fibre. Lint wei*bt, high insubtin* value, easily worked. Pipe ins.--S ft sections or segments, nom. thicknesses of 1 in. through . 8 in. Block--18 and 36 in. lengths: 8^6,9,13 in. widths, 1 through 4 in. Asbestocel For aervioe to 300F Rook Cork For service from -300F to +2007 Cellular type insulation for use on pipes conveyin* low pressure steam and not water. 3 ft sections in standard thteka^ro of 3 to 8 [dies, meb ply approx U in. thick. Modsttue^esistajtt insubtion for all re frigeration applhatioos. Sanitary, odor less, fire-resbtant. Sheets: 18 in. z 38 in. thieknesso to 4 in. Pipe Ins.--3 ft sections in lee Water, Brine, Heavy Brine thick- J-MNo.301 Insubtins Hydraulin writing, coo-coat application SO-lb bag* cement for instuatin* small pipe fitting. Covering capacity, 86 bd ft per 100 lbs. J-M No. 450 Insubtin* Cement Mineral wool cement with excellent ad hesion to either hot or eold surfaces. 60-lb bags Covering capacity, SO lb ft per 100 iba. J-MIfaWInsttlatin* Asbestoscement for insulating pipe fittings 50 and 1004b bags or for use as finish over other insulation. Covering capacity, IS bd ft per 100 lb*. * Abo avaflable to fit straight rasa of copper tabic* with nominal diameter* from ft in. up.  452 Lockport Mills, Inc. Dept. C Lockport, N.Y, Thermal and Acoustical INSULATION Insulation Five featured types to meet every insulation need: (1) OPEN BLANKET backed by tough, waterproof, as phalt-coated kraft paper to form an effective vapor barrier. (2) ENCLOSED BLANKET. Insulation com pletely enclosed in envelope, asphalt-coated paper on one side, porous or "breather" type paper on other. (3) OPEN ALUMINUM FOIL All the features of Open Type (1) plus the extra value of aluminum foil back ing. Effective vapor barrier ... stops 90 percent of radiant heat. (4) ENCLOSED ALUMINUM FOIL. Superior in insulation plus values and thermal effi ciency. (5) DOUBLE FOIL, aluminum foil on top and back, plus superior Lo-K Blanket efficiency for tops in insulating value. ' Lockport's TEMP-LO A New Type of Semi-Rigid Insulation Improved processing makes possible a new and better semi-rigid blanket with greater thermal efficiency and ease of installation. It is light in weight, nonirritating and made in all standard sizes, styles and backings. Distributing agencies now being established. Write for details. . Thermal Conductivity--The "k" value for cotton is 0.24 Btu/hr/sq ft/degree F/inch. (See table.) Light Weight--Weight of 1 cu ft is % lb. (See table.) Flame-Proofed--Withstands 1800F blow torch heat. ' Moisture-Resistant--Chemical treatment, com bined with natural protective coating on cotton fibres, enables cotton to effectively resist moisture. Prevents rot and mildew. Smooth Texture--No sharp particles to irritate the skin. Easy to Warehouse and Handle. Offers far more "compressibility." Requires one-third the trucking and warehouse space of ordinary insulation. Simple arid Economical to Install. Saves from 25 to 40 percent in costs. . Designed to Maintain Maximum Utility. - Resists all types of deterioration. Won't sag or settle. Packaged in Rolls. INSULATING .VALUE OF VARIOUS INSULATORS* The coefficients of conductivity (ifc value) are expressed in Btu per hour per square foot per degree Fahrenheit per 1 in. of thickness. Type of Insulation Value Cotton: Insulating Batt........................... Rock Wool: Fibrous material made from Mineral Wool: Fibrous material made from mineral slag................................... Glass Wool: Fibrous material made from glass slag........................................ Rigid Insulation made from sugar cane Chemically treated wood fibre between layers of paper........................................ Eel grass between layers of paper......... Stitched and creped expanding fibrous Shavings: Various from planer................. Corkbosrd: No binder added................. Rigid insulation made from wood fibre.. .875 10.00 1.50 13.50 3.62 3.40 1.50 8.80 7.00 15.90 0.24 0.27 0.27 0.27 0.33 0.25 0.25 0.27 0.41 0.27 0.33 * Compiled from Chapter 9, 1954 Edition, k " indicates temperature conductivity. Insulation 453 Reflectal Corporation A subsidiary of Borg-Warner Corporation 200 S. Michigan Ave., Chicago 4-, Illinois UNIQUE REFLECTIVE INSULATION ALFOL Is : ALFOL is a reflective-type insulation consmwng of multiple aluminum foil layers in handy blanket form, designed to combine high thermal efficiency with positive vapor control, ALFOL is ideal for all types of residential, com mercial and industrial buildings. How ALFOL works: Utilising the reflective inniiUHng prjn- cxple, the patented ALFOL blanket effectively resists all 3 forms of heat transfer. (1) Self-spacing sheets of pure alumi num foil reflect 95 percent of all radiant heat. (2) Convection is blocked by these same foil layers. (3) Multiple "captive" air spacM hold conduction to the minimum. The result is a com bination of benefits that Is totally unique. PRINCIPAL ADVANTAGES OF ALFOL High year-round efficiency: In resisting up-flow (winter) and! honrontal heat transfer, ALFOL efficiency is comparable to that of normal bulk insulation. In resisting down-flow - (sumrrrer) heat transfer, ALFOL is decidedly superior. The JMUlt isjui overall efficiency profile that is truly outstanding. NOTE: See Chapter 9, Table 3 for characteristics of aluminum insulation. ' Extra air-conditioning economy: Low heat storage capacity, combined with the decided slimmer advantage cited above affords substantia] savings in air conditioning. Reliable condensation control: A separate vapor barrier (consisting of polyethylene lining, foil or duplex-backed kraft) is a component feature of all ALFOL types. This positive continuous vapor barrier guards against condensation. ' Rapid: application: Self-spacing Action of the un usual ALFOL blanket makes installation virtually fool-proof and its speed of application means low installed cost. * Additional a""dv'antages: ALFOL ius ctleano, perm*arnnent, odor. and complleetely uniform in aqualitvy. With 9! ALFOL _ _ to choose from, you specify what you need . ana net what you specify. AN ALFOL TYPE FOR EVERY PURPOSE (A) Standard ALFOL Types: for normal inaulnting require ments. Available in various combinations to provide 2 3 or 4 reflective air spaces. Designations: Type l. Type 1A Type 2, Type 3, Type 4. ^ .(B) Heavy-duty ALFOL Types: for utmost insulating per fovrminannmc.et. SMimixuiliaori tMoI S0UtaUnUdUaUrd Types, but with heavy reinforcing for extra rigidity anda "boooxx--ttype" end-desigen ge-to-edge coverage. Desimations: Types 22F . ,, r"?'^22t ('"w'i"thi poliyethnyliene boacckningg)j, Ttyyppes 44Fif and 44. ao A"t*; . TVyni*M8 aArrp AavvaaSilIaabKlUe iinn nwiindrtkhas Atona_c_c_o_m__m_oJd.a.t.e lJ-iii-, 16-in., 20-in. and/or 24-in. framing centers. Blankets are packaged in cLounutminiuouuas-liengtmh roulls oorf 5o0u0u or 255U0 sq ft. FREE D'aAtIAa BRormolkr. FPao,r .cnommnpllAettae technica1l Jd_aAt_a a. .n. dJs_p_ecifica tions. wnte for 28-page ALFOL Data Book. This colorful manual is available free to architects and engineers Standard ALFOL blanket is available in 5 types for vary ing thermal needs. Type 2 (shown) has 2 aluminum foil sheets that expand automatically to deliver 3 reflec tive air spaces. Duplex-lined kraft backing provides positive vapor barrier Heavy-duty ALFOL blanket is heavily reinforced, has "box-type ' design for edge-to-edge fit. Type 44F (te/t) provides 4 reflective air spaces for maximum perform ance. Type 22F (right) features polyethylene lining for extra condensation safety . Ideal for sidewall installations, A1JOL combines high thermal value with ^ the vital protection of a positive, continuous vapor harrier. Installed (ihotrn here) in residential ceiling, ALFOL provides normal ef ficiency in winter, decidedly superior efficiency in summer. Industrial "exposed ceiling'' instal lation of ALFOL. Here, Type 44F (shown) provides full insulation plus a semi-finished ceiling. #454 Insulation Mtom American Flange & Manufacturing Co. Inc. 30 Rockefeller Plaza, New York 20, N. Y. Plaza 7-2200 TerroJherm Reg. U. S. Pat. Off. METAL INSULATION FULLY PROTECTED BY U. S. AND FOREIGN PATENTS Reduces Fuel Costs 25-30 percent Installed in ceiling (or roof) and exterior walls, FerroTherm reduces fuel costs by an average of 25 percent to 30 percent. In ceiling (or roof) alone, Ferro-Therm will reduce fuel costs by 15 percent to 20 percent. During the summer, the installation of Ferro-Therm metal insulation will reduce temperatures in the house by 10 F. to 12 F. . Gives the Protection of Metal Ferro-Therm is stapled permanently in' place Because Ferro-Therm is metal (1) It is not only non combustible; it is an effective fire stop for wooden Ferro-Therm framework; (2) It prevents the penetration of ter mites, rodents and insects; (3) It does not absorb Reflects 90-95 percent moisture or convey any wood-rotting moisture in fram of All Radiant Heat ing members; (4) It does not settle or pack down, as the sheets are stapled permanently in place; (5) It is Ferro-Therm Metal Insulation, available from sheets absolutely permanent. - or coils of aluminum or steel with a special alloy coat ing, reflects 90 percent to 95 percent of all radiant heat. Ferro-Therm This high reflectivity, combined with extremely low heat storage capacity, provides maximum insulating ' efficiency in a minimum overall thickness. * - - Is Easy To Install-- and Economical Ferro-Therm takes up considerably less space than mass insulation of equivalent efficiency. Laboratory Reflects Heat From Either Side tests and thousands of applications have demonstrated that a wall of Ferro-Therm will provide insulating ef' ficiency equivalent to mass insulation approximately Ferro-Therm's high reflectivity enables it to resist the twice' as thick. And Ferro-Therm can be installed penetration of heat from either side. During the winter easily, quickly and economically. The sheets take up it reflects heat in; during the summer it reflects heat' considerably less space than mass insulation. And they out--assuring year 'round comfort and a considerable ' ' are light--easy to transport and handle. One man can saving in fuel. install 1000 to 1200 sq ft of Ferro-Therm in a day. Insulation INFRA INSULATION, INC. 525 Broadway, New York 12, N.Y.-WOrth 6-4314 . %455 This insulation has 7 INCHES insulation value in WINTER - U .04 - C .043 - R U) 23.32 heat flow UP Hunches insulation value in{ WINTEr} "U.03-C .029-RU) 34.16 heat flow DOWN 9 Aluminum Heat-Resisting Spaces, Tough, Non-Perforated Aluminum Laminates - Top and Bottom TYPE 9-LL Scientific Infra insulation insulates against Heat, Vapor, Dripping Condensation, Timber Rot, Wet Plaster, Peeling Paint, Discomfort Recent research by the National Bureau of Standards reveals how multiple layers of aluminum and air spaces drastically reduce Heat-Flow by Convection- Conduction in addition to Radiation. TOUCH, FUU-OOTH CHART OF SOME INFRA INSULATIONS- Performances and Prices no. or SPACES TYPE illustration PRICE DIRECTION PER SO. FT. - OF HEAT ROW U <Btn) c ffitn) R Noth-MetatlU Inwlotloa (I) equivalents in inchest 6 6-LL 74 UP DOWN .0$ .068 14.64 .03 .034 29.48 444" 9V." 4 4-U. UP .08 .105 9.52 3Vi" 54 DOWN .03 .038 26.18 8%' WALL .06 .068 14.65 4*f 3 3-LL 1 44 UP DOWN WALL .10 .143 7.00 .04 .046 21.79 .08 .101 9.92 2V4" 7Vs" 354" 8 8-LL 7 7-AL 5 5-AL 10ft UP 00WN UP 8d SOWN 6* UP .DOWN .04 .03 .OS .03 .07 .03, .049 .030 .057 .032 .082 .034 20.47 32.99 17.58 31.28 12.13 29.00 644" TO* 544" 1054" 4* 944' rSfitSyW SiTlTiiiii?**??; *!* V I y*** * ** of 3% Mittem*. DtbratMB * mthti fi UMil Sana* ( Staatertt la tJ.H.f.A. 8can ftntr jCvtvaM llama, ttnal man dt* ia ftt LLL-f-UU; HB-I-S83; BB-1-521*; BH-l-SSIa. Hm,loMl^i4t.u2000^. Scientific construction of multiple layers of aluminum, fiber and air spaces winimiy^B condensation on or within the insulation. There is slight capacity for absorbing water. These insulations, with a.long and continu ous (up to 500 ft.) non-porous vapor and water barrier on top as well as on bottom, made of genuine non-perforated metal of al most zero permeability, help protect against dripping condensation from above if any, timber rot, peeling paint, wet plaster,, crum bling masonry, rust and insects. For additional information and a free copy of Housing Research Paper 32, write to Infra Insulation Inc., Dept. G-9, 525 Broad way, N. Y. 12, N. Y.  456 insulation somu Reflectal Corporation A subsidiary of Borg-Warner Corporation 200 S. Michigan Ave., Chicago 4, Illinois FOR UNDEVIATING CONTROL OF SOLAR HEAT What KoolShade it: KoolShade Sunscreen is a.sun control device consisting of tiny horizontal louvers permanently interwoven with tough vertical warp wires (see illustration A). Functional and attractive, the result is a durable solar screening that combines optimum shading efficiency . . . with minimum possible obstruction of IhIow'KootShade^rorlcs: Operating like a tiny Venetian blind installed outside the window, KoolShade intercepts the sun's rays before they reach the glass. Illustration B shows how its tiny louvers (spaced 17 or 23 to the inch, depending on the type} screen out up to 100 percent of the direct solar rays. PRINCIPAL ADVANTAGES OF KOOLSHADE Reduces air conditioning costs: The ideal adjunct to air conditioning, KoolShade can sharply reduce initial tonnage requirements. (By rule of thumb, each 100 sq ft of KoolShade replaces the need for about 1 ton of cooling capacity substantial savings in cost.) Also, KoolShade increases the efficiency of the cooling unit... hence cuts operating and maintenance costs. . .- , Balances winter heating load: By eliminatingsolar hot spots (a major cause of system imbalance). KoolShade promotes more efficient winter heating. Cuts costa by reducing the need for excessive adjustment of thermostats. Eliminates eye-straining glare: Widely used for daylightmg control, Koolbhade moderates sun and sky dare to improve lighting balance, minimize fall-off.. . guard against eyestrain. Yet the extra open area afforded by KoolShade s exclusive woven design admits ample light and air ... and 83 percent clear outward visibility^ Weather resistant . . . never needs painting* Electrostatically coated with weather-proof nubelon enamel, KoolShade requires virtually no maintenance--less by far ordinary insect controls. And it enhances architectural appearance. KOOLSHADE FRAMING AND INSTALLATION For peak efficiency, durability and appearance, KoolShade is installed in KoolFrame aluminum extrusions designed exclusively for use with KoolShade. Custom-fabri cated to acenTnmfwiate fenestrations of any type or shape, KoolShade screens are sold and installed only by Franchised KoolShade Distributore. Their specialised ex perience is your assurance of a quality installation every time. (A) Magnified view (inset) shows how KoolShade louvers are literally woven in place. Background photo (screen shown actual size) demonstrates 83 percent clear outward visibility FREE Shading Data Calculator avail able on request to engineers and architects. Convenient slide chart--* with handy inserts for 4 different latitudes--provides *un position, heat gain and shading data at a glance for any window orientation, any season. An invaluable tool for figuring solar heat loads (B) Side view of louvers (Type LSA, magnified) illustrates KoolShade efficiency in screening out solar heat and glare at various sun angles Air conditioned. Savannah (Ga.) Memorial Hospital reduced cooling load by 74 tons with KoolShade. Net savings in cooling tonnage alone amounted to 830,300 ' Installed after air conditioning, KoolShade was used at North Ameri can Life Building (Minneapolis) to eliminate solar "hot spots," cut operating costs Used as adjunct to air conditioning at Los Angeles County Engineers Building, KoolShade reduced solar heat load 72 tons, saved $13,300 in equipment Insulation 457 WOOD CONVERSION COMPANY Dept. 220-9, First National Bank Building, St. Paul 1, Minnesota New York Chicago Boston Kansas City. Detroit Atlanta Buffalo St. Paul Minneapolis San Francisco . For many years a leader in the insulation field, Wood Conversion Company manufactures a complete line of flexible fiber and rigid insulation for industrial and - domestic purposes. Basic product categories include Balsam-Wool blanket insulation, Nu-Wood structural insulation and Nu-Wood interior finish board. Balsam- Wool insulation is the product of scientific research, ' and is especially designed for insulating efficiency and positive application. . - BALSAM-WOOL BLANKET INSULATION WITH REFLECTIVE LINERS--The wood fiber in sulating mat of this newest Balsam-Wool insulation is bonded with asphalt to reflective liners. Both reflective surfaces reduce heat transfer by radiation across the wall, floor, or ceiling air space. Balsam-Wool thus re ' duces heat transmission three ways by conduction, convection and radiation. Application spacer flanges . assure an effective tnKnlaf.ing; air space or reflective . surface on each side of the Balsam-Wool blanket. - WITH ASPHALT LINERS--Regular Balsam-Wool is identical to the reflective liner type except that liners are formed of asphalt saturated and coated kraft. The warm side barrier protects the wood fiber insulating mat from condensing moisture; cold side liner reduces convection through the insulating mat and reduces air infiltration. Balsam-Wool insulating, mat is uniform in thickness. Proper application is as sured by built-in spacer flanges along blanket edge which are stapled to framing members. PRODUCT ADVANTAGES Integral continuous vapor barrier. Provides air spaces on both tides of blanket. Fire-resistant insulating mat. Low thermal conductivity-value. - Resists settling or shakedown. Blanket and air spaces correctly positioned by spacer flanges. Wind-resistant liners. Rugged product construction . . . stands up under rough handling. NU-WOOD INSULATING BOARD PRODUCTS NU-WOOD SHEATHING--A strong, structural insulating sheathing in y$-w. and 2^2-in. thicknesses; asphalt impregnated for moisture protection. NU-WOOD ROOF INSULATION--Will fill all re- quirements of federal specification LLL-F-32 lb. Furnished in various thicknesses in plain and asphalt impregnated types. , . * ' SIZE DATA . BALSAMWOOL NU-WOOD SHEATHING NU-WOOD ROOF INSULATION Reflective liners---Standard (1 in.) and Double-Thick (2 in.)--16 in. and" 24 in. ' " Regular Liners--Standard (1 in.) and Double-Thick (2 in,)^-12 in., 16 in., 20 in. and 24 in. ' Regular Liners--Type E (Economy) ( in.)--12 in. and 16 in. in. Thick--2 ft. x 8 ft. Shiplap Edge; 4 ft. x 8 ft., 9 ft. Square Edge y$ in. Thick--2 ft. x 8 ft. "V" Joint Edge; 4 ft. x 8 ft., 9 ft. Square Edge in., 1 in., 1^ in. and 2 in. Thicknesses--24 in. x 48 in. or 23 in.. x 47 in.  458 insulation Rm( c*tiiu April Showers Company, Inc. 5980-88 Sligo Mill Road, N.E. Washington 11, D. C. PATENTE__D_ U T O M A T I C ROOF COOL1I (Trade Mark Reg. U. S. Pat. Off.) Distributors and Dealers in Principal Cities AUTOMATIC EVAPORATIVE ROOF COOLING Insulation rm< c.n,g 459 FANJET DIY. - Muellermist Irrigation Co. 2616 S. Ninth Ave., Maywood, Illinois AUstin 7 -7806 FELLmore 4-7806 FANJET "patented" Roof Cooling Patent No. 2^34,635 illustration shows typical April Showers installation AUTOMATIC EVAPORATIVE ROOF COOLING SYSTEMS Spray Method The April Showers Automatic Roof Cooling Systems are designed to stop solar heat at its source by evapora tive cooling. They have been used extensively since 1934 for under-roof cooling of industrial and commer cial buildings or to reduce initial and operating costs where a true air conditioning system is contemplated . or in use. In the latter case, total tonage requirements are substantially reduced and operating coks cut an average of 25 percent. April Showers Systems are completely automatic. The control thermostat is set to turn the system on at about 10 degrees above designed wet bulb temperature. A four degree drop shuts of! the spray, holding the roof surface temperature at about 8 degrees above wet bulb temperature. This lowers under-roof temperatures 8 to 15 degrees. Not only is the roof temperature affected, but all supporting upright members and walls since the heavy, cool air spills down over them thus cooling them, too. ' It is important to note that the April Showers Spray- head is scientifically designed to produce a fine DROP LET--not a mist. This produces a fine film of moisture on the roof which permits excellent evaporation; the action that creates lowered temperatures. April Showers operate on average city water pressure or utilize well or condenser waste water. Consumption is low, each Spray-head uses about 0.4 gpm and covers about 200 square feet. They operate an average of one minute in five; usually 15 or 20 seconds per spray pe riod- ---- Today, there are over 25,000,000 square feet of roofs that are cooled by the April Showers Automatic Spray Method Systems. They are operating on many of the country's leading- industrial plants and commercial buildings with gratifying results. April Showers fit all shapes and sizes of roofs, help prevent roof fires, act as Lightening arrestors, add longer life to composition roofs and there is no run-off. Estimates are made without charge; however, certain pertinent data is necessary to establish the factors that govern each individual installation. Ask or write for Form E-10&. Our Engineering Staff stand ready to give you every assistance. Patent Nos. 2,069,150--2^66,321--2,554,409. Other Pat*. Pending. ' FANJET--The certified automatic Thermo-Controlled Non-Clogging Roof Cooling System (Approved by Leading Roofing Companies) --Delivered anywhere in the U. S. or abroad-- Reduces Inside Temp 8-15 Degrees. Reduces Roof Temp 40-60 Degrees. " Reduces Air Cond Operating Cost. Reduces Air Cond Initial Cost. Reduces Personnel Turnover. Reduces Production Rejects. Increases Employee Efficiency. Increases Life Of Air Cond. System. Lessens Radiant Heat Rays. Lessens Solar Heat. ' Eliminates Pipe Clogging. . Increases Roof Life. Lessens Roof Dust ' Provides Cooled Area Over Workers. ' Acts As Lightning Arrester. Prevents Thunderstorm Shock To Roof. Promotes Good-Will Towards Management. Absorbs Internal Heat Up Through Roof. GUARANTEED Protection For The User. GUARANTEED Spray Orifices (NON-CLOG). GUARANTEED Workmanship (FIVE Years), GUARANTEED Intermittent Operation. GUARANTEED Materials (FIVE Years). GUARANTEED UNION Manufactured. GUARANTEED Non-Ferrous Materials. GUARANTEED No Water Wastage Or Runoff. GUARANTEED Spray Coverage. GUARANTEED To Use HARD Water. GUARANTEED Trouble-Free. GUARANTEED To Operate On 20 psi. GUARANTEED To Have Pipe Supports. GUARANTEED Sweat Fitted. GUARANTEED Line Drainage. WARRANTY Of Manufacturers For Thermostats, Humidity And Timing Devices. CERTIFIED PLAN with every PROPOSAL AND ESTIMATE Some USERS: TUNG-SOL ELEC.-FEDERAL TELECOM. LAB.--LOCKFORMER CO --MARCAL CO.-- LAVEZZI MACH. WORKS--CARTER PRODUCTS CO.--SOLA ELECTRIC CO.--AMERICAN NAMEPLATE CO.--OKLAHOMA TIRE & SUPPLY CO.--KAILER YOUNGQUIST CO. WHY WE GUARANTEE OUR SYSTEM WILL NOT CLOG BECAUSE DURING the "patented" PIERCING operation, the copper tube immediately surrounding the opening being formed, becomes dished. Such dishing is automatic and is concomitant of this method of forming the opening. The depth of the dishing may be varied by modifying the physical characteristics of tube or tool. Immediately concentrically surrounding opening at the tube is dished radially inward. Because of the self-cleaning action produced by the flow in passing through the FrustoPyramidal opening, this opening may be extremely small while yet avoiding the clogging tendencies of the openings now found in other spraying devices. DEPENDABLE LOW COST EVAPORATIVE ROOF COOLING  460 Publications THE AMERICAN SOCIETY OF REFRIGERATING ENGINEERS 234 Fifth Avenue New York 1, New York AVAILABLE The ASRE Data Books have been completely re designed and rewritten to fit the needs of the greatly expanded refrigeration and air conditioning industry. NEW FORMAT Larger 8M x 11 in. Page Size Larger and More Legible Charts and Tables GREATER ACCURACY & COVERAGE All Material Organised, Prepared and Checked at Each Stage of Production Before Publication By 15 Technical Committees 55 Chapter Editors & Co-Editors . 8 Associate Editors The Editor-in-Chief ADVERTISING Manufacturers & Products Index Including New Technical Inserts with Design Specifica tions for Selecting Equipment 600 Cross-References for Products of More Than 3,000 Manufacturers NEW CONTENT 53 Up-to-Date Chapters Including m 15 Chapters Covering Subjects Not in Previous Data Books 400 illustrations . Over 200 Tables ' About 1000 Pages Complete ASRE Refrigerant Designation System Names, Addresses and Publications of Domestic and Foreign Air Conditioning & Refrigeration Associations 25 percent discount to ASHAE Members if order is accompanied by payment. $12.00 the copy, sent postage free if paid in advance. Mail your orders to: ' THE AMERICAN SOCIETY OF REFRIGERATING ENGINEERS 234 FIFTH AVENUE, NEW YORK 1, NEW YORK Publications 461 ASHRAE Journal Successor to Refrigerating Engineering including Air Conditioning, and incorporating the ASHAE Journal. As an outcome of the voted merger of The American Society of Refrigerating Engineers and the American Society of Heating and Air-Conditioning Engineers to form the American Society of Heating Refrigerating and Air-Conditioning Engineers, Inc., the monthly publications of these two organizations have been combined. Thus, the ASHRAE Journal becomes the primary source of authoritative information upon current prog ress in all aspects of the engineering of equipment and facilities for the heating, cooling, conditioning, venti lating and refrigeration of living, working, industrial- processing, commercial, recreational, transportation and warehouse areas. ` ASHRAE Journal is larger in content and essential coverages than were predecessor publications. It has a circulation of approximately 20,000. Feature content includes reports and discussions upon research, design, engineering, development and tests of equipment and upon the properties, performance, characteristics of materials, refrigerants, products and parts. As the official publication of the Society, the ASHRAE Journal presents outstanding papers sponsored at So ciety meetings by members mid invited authors. Included is news of the ASHRAE Chapters; of Stand ards, Codes and research projects, and other matters of interest to the membership. Members of ASHRAE receive the Journal without additional charge. Non-member subscriptions to Refrigerating Engineer ing are being continued to the ASHRAE Journal to the limit of the subscription interval. CODES AND STANDARDS ASRE further contributes to refrigeration progress by establishing Codes and Standards in the industry. These Standards cover approved methods for testing and rating various, types of air conditioning and refrigerating equipment. Also included is the B9 Safety Code for Mechanical Refrigeration. Sold sep arately, or a complete set for $10. REFRIGERANT TABLES, CHARTS, AND CHARACTERISTICS A handy 6)4 x 9 in. volume containing the thermo dynamic properties of all refrigerants now in use (re printed from ASRE Data Book), forms a convenient reference for design and application engineers, contrac tors, professors and students. $3.50, cloth bound. DESIGN VOLUME--ASRE Data Book -' ./ The last edition (1957--58) of the old senes, this volume will not be revised until 1961. It is a standard reference work containing fundamental data, refrigerant tables, description of the different cycles, systems, and component parts. A must for the design or application engineer. $10.00 the copy. . . Mail your orders to: THE AMERICAN SOCIETY OF REFRIGERATING ENGINEERS . 234 FIFTH AVENUE, NEW YORK 1, NEW YORK  462 Publications Coal-Heat Published at 20 W. Jackson Blvd., Chicago 4, Illinois Phone Wabash 2-9464 New York City, MUrray Hill 8-6380 To Get the Facts about heating and fuel requirements, heating costs, operating and maintenance problems, the equipment situation, personnel, performance standards, fuel eco nomics, and service--this is what we are trying to do, here at COAL-HJEAT: These are the fundamental factors that affect the market, the use and sale of fuel and equipment, one's job, or business. So, it is our aim to get and print "the low-down" on these in each of the'following markets: Many of these plants and buildings are old, the equipment is in poor condition, operation leaves much to be desired, costs are excessive. Since most janitors, building owners,. members of school and hospital boards are not well informed about heating or the proper use of fuel, we face a tremendous educational job--a job that rests largely on the retail dealer and the salesmen because they alone come in 1. Apartment houses 2. Churches 3. Dept. & other stores 4. Dairies 5. Greenhouses 6. Hotels 7. Hospitals 8. Institutions 9. Laundries . 10. Municipal & govt, bldgs. 11. Mfg. plants ' 12. Office bldgs. " 13. Residential 14. Schools . 15. Theaters & other bldgs. . To find out what each of us concerned should know about the particular needs, problems and possibilities in each of these fields, and to help make more of the facts known where they will do the most good--this is . our purpose! Together, these groups represent some. 20-million plants, buildings, homes, 160-million tons of coal annually--the nation's largest fuel market, in either number of tons or customers. See "Heating-Fuel Markets"--$1.00 a copy. periodic contact with these 20-million fuel users. To help provide the essential educational sales and service tools--that's what we're trying to do. To help keep more customers happy, get into more of the new buildings, help develop new business--these are the objectives of COAL-HEAT. It can help you get more business! - FUEL AND HEATING EQUIPMENT--SALES AND SERVICE Publications DOMESTIC ENGINEERING COMPANY 1801 Prairie Avenue, Chicago 16, Illinois 463 DOMESTIC ENGINEERING MAGAZINE Editorially keyed to the total business interests of qualified plumbing-heatingcooiing contractor-dealers who specify, sell, install and service. DE covers every phase of the contractor-dealer's busi ness: engineering, servicing, merchan dising, research, financing, new products, legal, news, legislation. Winner of 16 out of the 17 national editorial awards pre sented to publications in its field by Industrial Marketing since 1939, DE holds the loyalty and confidence of "buying core" contractors who do more than two-thirds of the industry's total annual volume--loyalty and confidence that pays dividends to Domestic Engi neering advertisers. .Member, Audit Bureau of Circulations. Published monthly, $5.00 per year. ACTUAL SPECIFYING ENGINEER The only business publication written specifically for the engineer who actually specifies products into heating, piping, plumbing, ventilating and air condi tioning systems.' Editorial formula and performance are completely geared to the subject of specifications and product choices and to the application of prod ucts in various systems. Circulation is made up of men who design systems and specify products, and includes: inde pendent consulting engineers specialis ing in mechanical systems; consulting engineers; engineers associated with architects; and specifying engineers associated with large industrial com panies, institutions and commercial chains, big contractors and distributors, government (in all categories), utilities, etc. Published monthly, $5.00 per year. DOMESTIC ENGINEERING CATALOG DIRECTORY Published annually as a buyers' guide classifications and 4,600 cross references. for large contractor-dealers and whole salers. Contains 6 sections of MANU FACTURERS' CATALOGS on: Boilers, Burners, Furnaces, Controls, Air Condi tioning, Refrigeration, Insulation, Pipe, Valves A Fittings, Pumps, Tanks, Appli ances, Water Heaters 4 Softeners, Brass, TRADE NAMES, an extensive list of over 10,000 with corresponding manu facturers' names. NAMES AND AD DRESSES of approximately 5,000 manu facturers in the Industry. TECHNICAL ENGINEERING DATA, complete ar Drainage Pipe, Tools, Compounds and ray of easy-to-read, easy-to-use charts, Oil. PLUS . .. CLASSIFIED DIREC graphs and tables. $12.50 per year. TORY OF PRODUCTS with 3,000 main ` $25.00 for three years. ENGINEERS' PRODUCT FILE Published annually for engineers who specify Heating-Cooling-Plumbing. Con tains 8 sections MANUFACTURERS' CATALOGS: Heating,'Air Conditioning, Ventilating; Heating-Cooling Controls, Specialties; Tanks, Heat Transfer Equipment, Water Heaters, Water Treatment; Piping, Tubing, Valves, Fittings, Fire Protection Equipment, Pipe Hangers, Pipe Insulation; Pumps, Lawn Sprinkler Systems; Plumbing Fix tures, Accessories, Plumbers' Brass, Specialties; Plumbing Drainage Prod ucts. CLASSIFIED DIRECTORY of thousands of products, names, location of manufacturers. TRADE NAMES, lists thousands with product, manufac turer. MANUFACTURERS' NAMES, ADDRESSES, thousands whose prod ucts are specified. TECHNICAL, ENGI NEERING DATA, 260 pages, basic tables, rules commonly used in systems layout, design. ' -  464 Heating Publishers, Inc. Publications 2 West 45th Street New York 36, N. Y. FUELOIL & OIL HEAT Now in its 37th year of publication; is edited for all oilheating and aircon ditioning men. Covers installing and servicing of all oilheating and aircon ditioning equipment, selling and merchandising from the dealer level. Technical articles, exclusive market reports on oilheating, airconditioning and fuel oil. The regular monthly Commercial-Industrial Section covers installing and servicing of heavy oilheating equipment, boilers, large capacity oil-fired air movers and heavy fuel oil. Member Audit Bureau of Circulations and Business Publications Audit of Circulation. Published monthly. One year $3.00--3 years $5.00. ' GAS HEAT AND COMFORT COOLING The complete heating and cooling magazine covering the use of equipment which uses gas as a fuel exclusively. Covers all forms of comfort heating and airconditioning; commercial-industrial, residential, etc. Technical articles, sales and merchandising, exclusive monthly report on gas heating and airconditioning retail equipment sales. Covers all equipment using gas for a fuel, airconditioning, water heaters, incinerators, furnaces, boilers, conversion burners. Edited for the retailer-installer, serviceman, contractor. Many readers are utilisation engineers with gas utilities. Now in its 9th year. Member of Business Publications Audit of Circulation. Published Monthly. One year $3.00--3 years $5.00. - ELECTRIC HEAT & AIRCONDITIONING A new magazine devoted to a relatively new art--comfort heating with electricity. Covers both residential and commercial applications. Electric hp-ating is coming fast, particularly in areas where the air conditioning load hag given the electric utilities a very large, peak summer load. When this peak presents a non-profit imbalance, the utilities create comfort heating rates -nd push hard for electric heating to build a winter load. It has zone control possibilities. In some areas insulation is recommended to make electric heating competitive. Electric Heat & Airconditioning covers all phasftfl of this growing industry including heat pumps. No engineer in hftftfing a.nd air conditioning should ignore this new art. This is the only publication 100 percent devoted to electric heating. Member of the Business Publications Audit of Circulation. One year $2.00--3 years $5.00. BOOKS OF PARTICULAR VALUE: "Fundamentals of Year-Round Air Conditioning Controls with Oil Heating" ($2.00 a copy). "Summer-Winter Air Conditioning Controls for Gas Heat & Comfort Cooling ($2.00 a copy). "Modem Gas Heating" - The first compilation of information devoted to gas heating installation and service work. Close to 100 pages with many illustra tions--13130 a copy. - "Better Oil Heating" . A service guide for operation and maintenance of oil burners. Bound in attractive paper cover 8J4 X 11. Nearly 100 pages, 125 illustrations, tables ana service hints. $2.00 a copy. 465 International Heating & Air-Conditioning Exposition Permanent Address--480 Lexington Ave., New York 17, N. Y. EXPOSITIONS HELD Philadelphia, 1959; Chicago, 1957; Philadelphia, 1955; Chicago, 1953; Philadelphia, 1951; Chicago, 1949; New York, 1948; Cleveland, 1947-1940; New York, 1938; Chicago, 1936; New York, 1934; Cleve land, 1932; Philadelphia, 1930. FUTURE SCHEDULE 2nd Southwest Heating & Air-Conditioning Exposi tion in Dallas--1960; scheduled for Chicago in 1961. UNDER AUSPICES OF A.S.H.A.E. These Expositions have been and will be held co incident with the annual meetings of American Society of Heating and Air-Conditioning Engineers, Inc., and under their auspices. Management is by International Exposition Company with permanent headquarters at 480 Lexington Ave., New York 17, N. "Y. EXHIBITORS Comprise leading firms in each phase of the industry; number has varied from 150 to more than 400 exhibi tors. EXHIBITS These range from and comprise all the types of ar ticles discussed or advertised in this copy of The ASHAE Guide. 1. The Combustion Group: Furnaces, burners (coal, oil and gas), grates, stokers, boilers, radiators (various types), refractories and auxiliaries. 2. The Oil Burner Group: 3. The Hydraulic Group: Water feeders, water heaters, pumps, traps, valves, piping, fittings, expansion joints, pipe hangers, etc. 4. The Steam Heating Group: Vapor heating, steam specialties. 5. The Hot Water Heating Group: 6. The Air Group: Warm Air furnaces and stoves, registers and grilles, cooling towers, air filters, motors, fans, blowers, condi tioning equipment, ventilators (room and industrial types), unit heaters, etc. 7. The Am Conditioning Group: Equipment which circulates and filters the air, in sum mer dehumidifies and cools; in winter heats and hu midifies, and does all these in proper season for com plete, all year-round air conditioning. 8. The Control Group: '. Instruments of precision for indicating, controlling or recording temperature, pressure, volume, time, flow, draft or any other function to be measured. 9. The Refrigerating Group: Compressors, condensers, cooling apparatus, contin gent apparatus and refrigerants. 10. The Central Heating Group: Apparatus and materials especially designed or adapted to the uses of central heating and central heat ing station supplies. 11. The Insulating Group: Structural insulators (refractory and cellulose mate rials), asbestos, magnesia clays and combinations thereof, pipe and conduit covering, etc., weather-strip ping, adhesives etc. 12. The Miscellaneous Group: - Electric Heaters, boiler and pipe repair alloys, liquids and compounds, tools of all kinds, and equipment not specifically included in the above groups, but related thereto. 13. The Machinery and General Equipment Group. 14. Books and Publications VISITOR ATTENDANCE Attendance is by invitation and registration only, thereby presenting a selected audience. Included are contractors, dealers, jobbers, supply houses, home owners, industrial users, professional and service or^ ganizations, public utilities, real estate management concerns, etc. A detailed analysis of registered attend ance is available on request. Industrial Expositions in America lead the exposi tions of the world in style, business effectiveness, in dustrial influence and educational value. This Exposi tion stands among the leaders in Industrial Expositions in America. It is an educational institution which brings together the research developments and im provements in equipment and materials for use in heating, ventilating and air conditioning all types of buildings. THE INDUSTRIAL PRESS 93 Worth Street, New York, 13, N* Y. Publications KEENEY PUBLISHING COMPANY 6 North Michigan Avenue, Chicago 2, III. 467 DESIGN OF AIR CONDITIONING SYSTEMS by F. W. Hutchinson 115 full-page charts solve problems of air . conditioning system design involving cooling load, duct design, psychrometrics, solar energy, comfort conditioning, panel cooling, etc. For each chart the engi neering and mathematical background plus design example and solution are given. 336 Pages, 118 Ulus., $7.00. DESIGN OF HEATING AND VENTI LATING SYSTEMS by F. W. Hutchinson 96 full-page charts solve problems of heating and ventilating involving load determination, duct design, panel heating, solar heating and combustion analysis. Companion Book to Design of Air Con ditioning Systems. Same methods to explain *nH solve problems are used. 320 Pages, 96 Charts, $7.00. By mail order. Canada and overseas, $8.50. SETT OF BOTH, $12.50. DESIGN OF INDUSTRIAL EXHAUST SYSTEMS by J. L. Alden How to build or buy an exhaust system that will meet the requirements of law and industry. Covers flow of fluids--hood forms--air flow through hoods--pipe resistance--piping design-- dust separators--low pressure conveyers --centrifugal exhaust fans--structural de tails--field* measurements and their in terpretation. 252 pages, 122 Ulus., $350. ELECTRICAL TESTING AND TROU BLESHOOTING by Philip Green Simple, straightforward, time-tested pro cedures show how to locate and correct faults in circuits of all kinds including controllers, motors, transformers and transmission lines. Most tests described are performed with the equipment iso lated from the power line. Written by an expert in electrical troubleshooting. 160 Pages, 34 Tables, $560. EXHAUST HOODS by J. M. DallaValle Practical hood design; latest principles of air handling, contaminant dilution and transport velocities; design of hoods for control of dust, mist, fumes, vapors, gases.' Simple formulas and diagrams show ex act procedures. 130 Pages, 127 Ulus., $4.00. FLOW AND FAN by C. H. Berry Covers the flow of gas through ducts, and fan performance and control; moving air through ducts, fan selection and control, duct arrangement, system characteristics, flow analysis. Basic data and methods used to calculate system resistance. Prac tical information for selecting a fan for. any duty. 232 Pages, 84 Illus., $460. FLUID FLOW IN PIPES by C. H. McClain How to solve' problems involving the flow of liquids and gases through pipes. How to handle viscosity, friction, heat, and other factors expressed in various dimensional systems. Worked-out prob lems show applications of principles. 124 Pages, 18 Illus., $460. FUEL OIL MANUAL--2nd Edition by P. F. Schmidt Covers characteristics and uses of every type and grade of fuel oil. Explains the meaning of each oil property, and shows how this information is applied is select ing, handling and burning fuel oil. A special chapter on fuel oil additives and another on troubles and- remedies. 176 Pages, 34 Tables, $450. HIGH TEMPERATURE WATER SYS TEMS by O. S. Lieberg A thorough explanation of the principles, design, selection of equipment, operation and economics of high temperature water systems. Contains original design data used in actual systems designed by au thor. Features design of typical system based on principles set forth in this brand new book. 224 Pages, 109 Illus- Tables, $650. . HANDBOOK OF AIR CONDITIONING, HEATING AND VENTILATING Edited by Clifford Strock Completely new book containing thou sands of facts, figures, data and principles on: Air Conditioning, Air Handling and Ventilation, Fuels and Combustion, Heat ing and Heat Transfer, Piping and Plumb ing, Motors and Motor Starters, Mathe matical Data and Drafting Room Symbols. Contains section on Terminol ogy and complete cross-index. 1094 Pages, 7% in. x lCm in., 598 Charts, Maps, Illus, 518 Tables, $1560. INDUSTRIAL HEAT TRANSFER by P. W. Hutchinson Provides 123 time-saving working graphs for the direct solution of most commonly encountered problems. Graphs are equal in accuracy to the equations from which they are derived and help eliminate errors in calculation. 336 Pages, 136 Charts and Illus^ $760. METHODS OF JOINING PIPE by J. E. York The most detailed information available on standard and special joints for all types of metallic, glass, tile, plastic and concrete pipe. Data on joints designed to take up movement due to expansion and contraction. 236 Pages, 249 Illus., $460. PIPEFITTERS HANDBOOK--2nd Edi tion by F. R. Lindsey ' v Original enable pipefitters to solve problems of pipe bending, mitering, lay out, threading, etc., either in the shop or in the field. Handy site, durable binding. 282 Pages, $660. PLANT AND PROCESS VENTILA TION by W. C. L. Hemeon Design factors and data that can be ap plied to any situation. Principles are clear, logical. Shows how to estimate ex haust characteristics of any. cold, multi directional process; and obtain exhaust requirements for such a situation. 448 Pages, 172 Illus., $960. RADIANT HEATING--2nd Edition by T. Napier Adl&m Latest developments, basic principles, facts, practical working data on applica tions of radiant energy for heating and cooling. Facts, figures, design data ean be applied directly in designing and in stalling radiant heating systems without calculations. 504 Pages, 337 Illus., $6.00. Prices slightly higherin Canada and overseas; write for catalog. Heating, Piping & Air Conditioning is the one monthly publication that adequately serves the field of industry and large buildings. It is devoted to the design, installation, operation, and maintenance of heating, piping and air conditioning systems in plants, commercial, institutional and public buildings. Each January issue includes a complete directory of commercial and industrial heating, piping, and air conditioning equipment, which lists all products, their trade names, and the. manufacturers* addresses. It is the one established buying and specifying guide of the industry. Heating, Piping & Air Conditioning is read by consulting engineers and architects ... contractors . . . and engineers in charge of heating, piping and air conditioning in industrial plants, and other large buildings, federal, state, and city governments, school boards, and public utilities. Most of ASHAE members are subscribers. 7 Such coverage means, for the advertiser, considera tion at all points in the selling of a heating, piping, or air conditioning product. .. consideration in its selec tion during the preparation of plans and specifications; in its actual purchase for installation; in its year'round buying for operating and maintenance require ments. Without waste, the manufacturer of air con ditioning products and equipment can reach through Heating, Piping & Air Conditioning those from whom he is seeking.the necessary engineering accept ance. AMERICAN ARTISAN is truly THE magazine of ` central residential air conditioning, warm air heating, and sheet metal contracting. Its readers are warm air heating and sheet metal contractors, dealers, jobbers, and manufacturers. Special features of each issue have been devoted to air conditioning since 1932, when it first became apparent ' that.air conditioning for homes was to be along the lines of the central forced warm air heating system. As a result of the ready adaptability of this type of heating system to all air conditioning factors, hundreds of thousands of homes today have winter air condition ing--supplied through forced warm air heating with air cleaning and humidification. Cooling apparatus can be attached to these systems readily whenever year*round air conditioning is desired. Each January issue includes the only complete directory of central residential air conditioning, warm air heating, and sheet metal products and equipment,/''' ' which lists all products, their trade names, and-the manufacturers' addresses. The key man in the central residential air con ditioning picture is the warm air heating and sheet metal contractor--the one man experienced in "treating air" at a central place and getting it properly distri buted. And AmericanArtisanisthekey publication-- because it reaches these key men with information that has made it the recognized authority on correct practice in residential air conditioning, warm air heating, and `sheet metal contracting. SUBSCRIPTION PRICES--U. S. A. $3.00 a year. SUBSCRIPTION PRICES--U. S. A. $3.00 a year Canada, $5.00 a year. Spain, Central and South America--$6.00 a year. Elsewhere $7.00 a year. (Prices subject to change without notice due to impending increases in postal rates.) MEMBER OF THE ASSOCIATED BUSINESS PUBLICATIONS AND THE AUDIT BUREAU OF CIRCULATIONS 46a Scott-Choate Publications 92 Martling Avenue, Tarrytown, New York Publications Subscription rates--$4.00 per year U. S., Canada and Pan America. Foreign, (6.00. Advertising rates on request. HEATING- & AIR CONDITIONING CON TRACTOR (formerly Sheet Metal Worker) is the leading magazine in the warm air heating, packaged air conditioning, ventilation, and sheet metal contract* ing industry. Its editorial scope includes not only resi dential heating and cooling work, but non-residential air conditioning and air distribution for comfort and process control. HEATING & AIR CONDITIONING CON-' TRACTOR editorial content is directed primarily at the management and planning levels of the heating, air conditioning, and sheet metal contracting business. It covers not only the technical aspects of this field, but also marketing, merchandising, business manage ment and legal problems. It is also the only publica tion in the field to devote regular monthly space to labor relations. Subscription rates--(4.00 per year U. S.f Canada and Pan America. Foreign, $6.00* Advertising rates on request. THE JOURNAL OF PLUMBING, HEAT ING & AIR CONDITIONING is the recog nized editorial leader in the plumbing and heating con tracting industry. Through the use of intensive edi torial research it has developed a unique formula for building effective readership. A key factor is consistent editorial balance among the various aspects of reader interest: technical, marketing, business management, overall industry issues. In technical editorial, The JOURNAL has consis tently been a pioneer. Among the subjects on which it has published the most comprehensive information ever produced are the following: baseboard radiation; sub mersible deep well pumps; hydronic air conditioning for residences and small non-residential structures; water conditioning for domestic and industrial use; etc. The JOURNAL is also the only publication in its field with a regular monthly section devoted to the labor relations problems encountered by large mechani cal contractors in their day to day operations. Publications Snips Magazine 5707 W. Lake St. Chicago 44, El. 469 PUTS A REAL PUSH BEHIND SALES A friendly, close-to-the-reader periodical published for those contractors who handle Warm Air Hearing, Air Conditioning, Sheet Metal Work, and Ventilation. SNIPS HOLDS THE LINE ON RATES To "hold the line" on our present advertising rates we did everything possible to reduce our costs. As a result there has been no rate increase since April, 1957. We were extremely happy that we wouldn't have to increase the rates as most trade papers have had to do, due to the recent postage increase and increases in the cost of paper, printing, cuts, etc. In fact, as a result of the drive made to get around these increases we came up with lower costs than before. EXTRA COVERAGE AT NO EXTRA COST We were able to put some of these savings into extra coverage. The final result was that while we promised a thirteen thousand coverage we have been able to give advertisers an extra thousand copies per month and still keep the rates the same. The Snips Magazine is preferred as an advertising medium by many notable industrial advertisers year after year, and many prominent jobbers and ^whole salers who know their market well. It's a unique periodical which helps you put a real push behind sales. LIVE STORIES IN SNIPS TOP INDUSTRY COVERAGE TO CONTINUE Even without this above mentioned coverage increase, we continued during the year past, to provide for you, the top coverage of the magazines serving the sheet metal, warm air heating, cooling and allied industries. No effort has been made to increase coverage promis cuously. Instead, every reader added has been a known, responsible buyer of the kind of goods you sell. SNIPS is packed each month, from cover to cover, with hundreds of live news stories and exclusive pic tures including practical applications of latest advance ments of the Sheet Metal, Heating, Air Conditioning and Ventilation trade. No long contributed stories. It's all field gathered material, secured the hard way, nibbing shoulders with the readers. Such work gets for the periodical a reader interest seldom found in a trade publication. You'll find this feature the basis of the sensational inquiry pulling power and sales pro ducing value of advertising space in SNIPS. ABOUT SNIPS' MAILING LIST It's truly a select group that gets SNIPS. They are the outstanding firms and individuals in the trade whom the better supply houses are selling or trying to sell. They are the contracting and installing con cerns whom the principal jobbers and distributors of the industry--people who really know their territories best--consider worthy of cultivation by mail, promo tion and salesmen's calls. MOST ADVERTISERS SELECT SNIPS FOR PAST 6 YEARS When your copy appears in SNIPS, it is in the peri odical which has carried more advertising accounts than any other magazine in this field for the past six years. This is in exclusion of the hundreds of listing ads carried each month. This continued preference for our magazine, as an advertising medium, is some thing of which we are extremely proud. The accom plishment challenges us to do a continually better publicity job to maintain this continued preference for our periodical as an advertising medium. MUCH TO MERIT USE OF SPACE IN THIS PERIODICAL There is much to merit your selection of the SNIPS Magazine as one of your advertising mediums in the coming year. It will be our constant endeavor to con tinue to give you the best trade paper advertising value available anywhere at any price. Special Issues ` January Annual & Winter Market Number--March - Anniversary & Spring Market Issue--September Fall Market Issue--December Holiday Greeting Issue--Fur ther information gladly sent on request. ENGINEERS OF HUMAN COMFORT The Heating, Ventilating and Air-Conditioning En gineers through their work and research bring to our homes, schools, offices, factories, theaters, hospitals and other public buildings in both summer and winter, that climate best suited to our comfort and health. These men realize the basic importance of heating, ventilating and air conditioning as a primary element in the well being of civilized mankind, hying and working mostly indoors. They are truly Engineer* of Human Comfort. MEN WITH VISION The professional status of this form of engineering today can be largely attributed to the American So ciety of Heating and Aib-Conditioning Engineers (ASHAE). Founded in 1894 by a handful of men de termined to elevate the dignity of their profession and provide the public with more than perfunctory service, the Society represents an organization of more than 12,087 members. It includes 74 chapters throughout the United States and Canada plus members in many for eign countries. On August 2,1894, Hugh J. Barron, the acknowledged founder of the American Society of Heating and Ven tilating Engineers (ASHVE), L. H. Hart, William M. Mackay, and 15 other interested men met in Mr. Hart's office in the World Building, New York City, to discuss the need for developing and disseminating technical ad vancements to heating and ventilating engineers. These men stimulated sufficient interest to obtain 75 charter members who met on September 10,1894, in the Broad way Central Hotel, New York City, and adopted a name, by-laws, and constitution for the new Society. Consistent with the increasing amount of activity by members in designing air-conditioning systems, in 1954 the Society changed its name to American Society of Heating and Air-Conditioning Engineers. SOCIETY SCOPE AND OPERATION The three major activities of the Society are: Mem bership service, Publication, and Research, the records of its accomplishments being permanently recorded in the annual Transactions. The Society membership now includes engineers, edu cators, scientists, physicians, architects, contractors, and leaders of industry. Membership consists of Hon orary, Life, Presidential, Fellow, Member, Associate, Affiliate and Student Grades. The management of the Society is entrusted to 4 elected Officers and a Council of 13 elected members. Continuity of policy is insured by electing 4 men an nually for a 3-year term and retaining the retiring presi dent on the Council for 1 year. Two Society meetings are held each year--the Annual Meeting during January or February, and the Semi- Annual Meeting usually in June or July. Every 2 years the International Heating and Air-Conditioning Ex position is held in conjunction with the Annual Meeting under the auspices of the Society. The MEMBERSHIP STATUS as of January 26, 1959 was as follows: Honorary Presidential Members Life Members Fellows _ Members Associate Members over 30 yrs Associate Members under 30 yrs Affiliates Students .. - .4 19 255 9 4,689 3,712 699 2,226 174 TOTAL 12,087 470 HEADQUARTERS AND LABORATORY The Society headquarters is maintained at 62 Worth St., New York 13, N. Y., and the ASHAE Research Laboratory, devoted to the study of fundamental prin- ciples of heating, ventilating and air conditioning, is located at 7218 Euclid Ave., Cleveland 3, Ohio. ASHAE DEDICATED TO RESEARCH From the day of its inception, a primary purpose of ASHAE was and still is research. For the first 25 years such research activity had been confined to individuals ' or committees utilizing available equipment or facil ities. . In January 1919 the Society approved the establish ment of a permanent research laboratory located in the U. S. Bureau of Mines, Pittsburgh, Pa. The Laboratory was moved in 1944 to limited quarters in Cleveland, . Ohio and in 1946 the Society acquired its present large, permanent quarters in Cleveland. The Society is justly proud of the fact that it is the only professional engi neering society that maintains and operates its own re search laboratory. ... All research activities are planned and supervised by the Committee on Research of 15 elected members, as sisted by various Technical Advisory Committees of the Society. Since 1919, approximately $2,500,000 has been expended on research, which has helped guide the in dustry to better practice and equipment. In addition to work at the Society's laboratory, a substantial part of the research program has been carried on through the medium of cooperative agreements with leading educa tional institutions of the United States and Canada. Together with the cooperating institutions the Society has, during the last year, conducted 22 research projects including work on Air Distribution, Fan and Air Noise, Hot Water Heating, Industrial Ventilation, Insulation, Odor Control Comfort, and Physiological Factors. The research activities are financed from Society funds, of ' which a portion comes from membership dues and from its publications, and these funds are amplified by con tributions from friends in the industries engaged in the general field of heating, ventilating and air conditioning. SOCIETY PUBLICATIONS Transactions--The first Society publication estab lished in 1895 provides a permanent record of Society activities published annually, containing scientific pa pers, proceedings of meetings, discussions, reports of meetings. Distributed to members as part of member ship service; and to others for $6.00. Journal--Contains advance publication of technical papers, the reports of Society and Chapter meetings, and other items of general interest. The Journal was published from April 1915 to October 1919 as a quar terly; 9 times a year from 1920 to 1924, then monthly from January 1924 to April 1929, and as a section of Heating, Piping & Air Conditioning magazine from May 1929 to December 1958. The Guide--A distinctly new service was inaugu rated by the Society in 1922 when it established the Heating Ventilating Am Conditioning Guide. Now- in 1959, as the 37th Edition makes its appearance, it is notable that The Gums has served effectively not only the membership but the entire profession and the allied industries, and has received world-wide recognition as a reliable and authoritative compendium of useful heat ing, ventilating and air-conditioning data. Throughout the 37 years of its service The Guide has become a reference book of unchallenged position in its special field of engineering. The intention of its foun ders, to provide an instrument of service containing reference material on the design and specification of heating, ventilating and air-conditioning systems and containing essential and reliable information concern ing modem equipment, has been carefully safeguarded^ by those responsible for the. compilation of each Edi tion. The Guide exerts today one of the most positive'influences tending to elevate, improve and extend the whole Art of Heating, Ventilating and Air Conditioning. It is universally recognized as .the most useful and authoritative work in its field, being used by practicing engineers, educators and manufacturers in all parts of the world, and as a text book by a growing number of the world's principal engineering institutions. 471 REGIONS AND CHAPTERS OF THE SOCIETY Under the Regional Plan adopted in 1956 the 72 Chapters are divided into 7 geographical regions, with regions headed by a regional director who is chairman of the Chapters Regional Committee for his respective area. The regional directors are MEMBERS o! the Council, and also comprise the Regions Central Com mittee of which the Second Vice President is chairman. Each Chapters Regional Committee meets once a year between February and May to discuss Chapter problems and select a member to represent the region on the Society Nominating Committee. Individual Chapters average eight meetings a year between September and May, which are distinct and apart from Society Annual and Semi-Annual Meetings. Region 1--Connecticut, Delaware, Maine, Massa chusetts, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, Vermont. Region 2*--Illinois, Indiana, Michigan, Ohio, Wis consin. Region 3--Colorado, Iowa, Kansas, Minnesota, Mis souri, Montana, Nebraska, North Dakota, South Da kota, Wyoming. Region 4--Arizona, California, Idaho, Nevada, Ore gon, Utah, Washington. Region 5--Alabama, District of Columbia, Florida, Georgia, Kentucky, Louisiana, Maryland, Mississippi, North Carolina, South Carolina, Tennessee, Virginia, West Virginia. Region 6--Arkansas, New Mexico, Oklahoma, Texas, and Shreveport, La. Region 7--All Provinces of Canada. Includes Iowa-Illinois Chapter. LOCAL ASHAE CHAPTERS Arizona--Phoenix, Aria. Arkansas--Little Rock, Ark. Atlanta--Atlanta, Ga. Austin--Austin, Tex. Baltimore--Baltimore, Md. Baton Rouge--Baton Rouge, La. Bluegrass--Louisville, Ky. British Columbia--Vancouver, B. C-, Canada Central New York--Syracuse, N. Y. Central Ohio--Columbus, Ohio Cincinnati--Cincinnati, Ohio Connecticut--New Haven, Conn. Delta--New Orleans, La. El Paso--El Paso, Tex. Empire State Capital--Albany, N. Y. Fort Worth--Fort Worth, Tex. Golden Gate--San Francisco, Calif. Illinois--Chicago, 111. Illinois-Iowa--Moline, I1L Tndinnrv Tndinnnpolin. Ind. Inland Empire--Spokane, Wash. Iowa--Des Moines, la. ' . Jacksonville--Jacksonville, Fla. Johnstown--Johnstown, Pa. FriTtrniri Wichita, Kan. Kansas City--Kan--r City, Mo. Long Island--Garden City, N. Y. Manitoba--Winnipeg, Man., Canada Massachusetts--Boston, Mass. Memphis--Memphis, Tenn. Miami Valley--Dayton, Ohio Michigan--Detroit, Mich. Minnesota--Minneapolis, Minn. Mississippi--Jackson, Misa. Montreal--Montreal, Que^ Canada Nebraska--Omaha, Neb. New Mexico--Albuquerque, N. M. New York--New York, N. Y. North Jersey--Newark, N. J. North Texas--Dallas, Tex. Northeastern Oklahoma--Tulsa, Okla. Northern Alberta--Edmonton, Alta., Canada Northern Ohio--Cleveland, Ohio Northern Piedmont--Greensboro, N. C. . Oklahoma--Oklahoma City, Okla. Ontario--Toronto, Ont., Canada Oregon--Portland, Ore. Ottawa Valley--Ottawa, Ont., Canada Philadelphia--Philadelphia, Pa. Pittsburgh--Pittsburgh, Pa. Puget Sound--Seattle, Wash. Chapitre de la Ville de Quebec--Quebec, P. Q., Canada Rhode Island--Providence, R. L Rocky Mountain--Denver, Colo. * Sacramento Valley--Sacramento, Calif. San Diego--San Diego, Calif. Savannah--Savannah, Ga. . St. Louis--St Lotus, Mo. Shreveport--Shreveport, La. South Carolina--Columbia, S. C. South Texas--Houston, Tex. Southern Alberta--Calgary, Alta., Canada Southern California--Los Angeles, Calif. Southern Piedmont--Charlotte, N. C. Southwest Texas--San Antonio, Tex. Toledo--Toledo, Ohio Utah--Salt Lake City, Utah Virginia--Norfolk, Va. Washington, D. C.--Washington, D. C. West Texas--Lubbock, Tex. Western Massachusetts--Springfield, Mass. Western Michigan--Grand Rapids, Mich. Western New York--Buffalo, N. Y. Wisconsin--Milwaukee, Wia. 472 F. PAUL ANDERSON MEDAL Id 1930 an endowment fund for the award of The F. Paul Anderson Medal was created by the late Thornton Lewis and Rules of Award were prepared by a special committee appointed by the Council. This award is in recognition of outstanding work in the held of heating, ventilating, and air conditioning. Since 1932 there were 16 awards: 1932 1936 1939 1942 Willis H. Carrier* Dr. Arthur Cutts Willard Prof. Frank B. Rowley Dr. Frederick E. Giesecke* Deceased . 1944 Comm. Ferry C. Houghten, U.S.NJ1.* 1946 Capt. Alfred E. Stacey, Jr., UBNJt. 1947 James H. Walker* 1950 Dr. Charles-Edward A. Winslow* 1951 Samuel R. Lewis 1952 Homer Addams* 1953 Everett N. McDonnell 1954 Walter L. Fleisher 1955 Charles S. Leopold 1956 Robert W. Keeton, MX>.* 1957 Prof. M. K. Fahnestock 1958 Prof. George L. Tuve ' 1959 Prof. Constantin P. Yaglou 1959--A. J. Hess 1958--E. R. Queeb 1957--P. B. Gobdon 1956--John W. Jakes 1955--John E. Haines 1954--Louis N. Hunter 1953--Req. F. Tatlob 1952--Ernest Szekely 1951--Lauren E. Seeley 1950--Lester T. Avert 1949--A. E. Stacey, Jr. 1948--G. L. Tuve 1947--Baldwin M. Woods 1946--Alfred J. Offnbb 1945--C.-E. A. Winslow . 1944--S. H. Downs 1943--M. F. BlaNkin 1942--E. O. Eastwood 1941--W. L. Fleisher 1940--F. E. Giesecke 1939--J. F. McIntire 1938--E. Holt Gurnet 1937--D. S. Boydbn PRESIDENTS OF THE SOCIETY 1936--G. L. Larson 1935--John Howatt 1934--C. V. Haynes 1933--W. T. Jones 1932--F. B. Rowley 1931--W. H. Carrier 1930--L. A. Harding 1929--Thornton Lewis 1928--A. C. Willard 1927--F. Paul .Anderson 1926--W. H- Driscoll 1925--S. E- Dibble 1924--Homes Addams 1923--H. P. Gant 1922--Jay R. McColl 1921--Champlain L. Riley 1920--E. Vernon Hill 1919--Walter S. Timmis 1918--F. R. Still 1917--J. Irvine Lyle 1916--Harry M. Hart 1915--Dwight D. Kimball 1914--Samuel R. Lewis 1913--John F. Hale 1912--John R. Allen 1911--Reginald Pelham Bolton 1910--James D. Hoffman 1909--William G. Snow 1908--James Mackat 1907--C. B. J. Snyder 1906--John Gobmlt 1905--William Kent 1904--Andrew Habvet 1903--H. D. Crane 1902--A. E. Kenbick 1901--J. H. KINEALY 1900--D. M. Quay 1899--Henry Adams 1898--WiltsTM F. Wolfe 1897--Wm. M. Mackat 1896--R. C. Carpenter 1895--Stewart A. Jbllett 1894--Edward P. Bates MEETINGS OF ASHAE ' ' Annual . Year Meeting Date 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th Jan. 21-23 Jan. 21-23 Jan-. 26-28 Jan. 25-27 Jan. 24-26 Jan. 23-25 Jan. 22-24 Jan. 21-23 Jan' 20-22 Jan. 19-21 Place New York, N. Y. New York, N. Y. New York, N. Y. New York, N. Y. New York, N. Y. New York, N. Y. New York, N. Y. New York, N. Y. New York, N. Y. New York, N. Y. 473 Semi-Annual Meeting None None June 18 July 15 None None July 12-13 June 16 July 17-18July 15-16 Place New York, N. Y. Atlantic City, N. J. Chicago, 111. Atlantic City, N. J. Niagara Falls, N. Y. Detroit, Mich. Annual Year Meeting Dale 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 11th 12th 13th 14th 15th 16th 17th 18th 19th 20th 21st 22nd 23rd Jan. 17-19 Jan. 16-18 Jan. 22-24 Jan. 21-23 Jan. 19-21 Jan. 18-20 Jan. 24-26 Jan. 23-25 Jan. 21-23 Jan. 20-23 Jan. 20-22 Jan. 18-20 Jan. 16-18 1918 24th Jan. 22-24 1919 25th Jan. 28-30 1920 26th Jan. 27-29 1921 27th Jan. 26-28 1922 28th Jan. 24-26 1923 29th Jan. 23-26 1924 30th Jan. 22-25 1925 31st Jan. 27-30 1926 32nd Jan. 26-29 1927 33rd Jan. 26-28 Place New York, N. Y. New York, N. Y. New York, N. Y. New York, N. Y. New York, N. Y. New York, N. Y. New York, N. Y. New York, N. Y. New York, N. Y. New York, N. Y. New York, N. Y. New York, N. Y. New York, N. Y. New York, N. Y. New York, N. Y. New York, N. Y. Philadelphia, Pa. New York, N. Y. New York, N. Y. and Washington, D. C. New York, N. Y. New York, N. Y. and Boston Buffalo, N. Y. St. Louis, Mo. Semi-Annual Meeting July 7-8 July 19-20 July 18-19 July 24-25 July 15-16 June 30-July 1 July 6-8 July 11-12 July 17-19 July 9-11 Sept. 16-17 July 19-21 July 18-20 June 26-28 June 10-12 May 26-28 June 14-17 fJune 6-7 \june 8-10 May 21-23 June 19-22 June 15-17 May 26-28 June 28-30 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 34th 35th 36th 37th 38tb 39th 40th 41st 42nd 43rd 44th 45th Jan. 23-27 Jan. 28-31 Jan. 27-31 Jan. 26-29 Jan. 25-29 Jan. 23-25 Feb. 5-9 Jan. 28-30 Jan. 27-30 Jan. 25-27 Jan. 24-28 Jan. 23-28 New York, N. Y. Chicago, III. Philadelphia, Pa. Pittsburgh, Pa. . Cleveland, Ohio* Cincinnati, Ohio New York, N. Y. Buffalo, N. Y. Chicago, 111. St. Louis, Mo. New York, N. Y. Pittsburgh, Pa. . 1940 46th Jan. 23-26 Cleveland, Ohio 1941 1942 1943 1944 1945 1946 1947 1948 1949. 47th 48th ` 49tb 50th 51st 52nd 53rd 54th 55th Jan. 27-29 Jan. 26-28 Jan. 25-27 Jan. 31-Feb. 1-2 Jan. 22-24 Jan. 27-30 Jan. 27-30 Feb. 2-5 Jan. 24-27 City, Mo. Philadelphia, Pa. Cincinnati, Ohio New York, N. Y. Boston, Mass. New York, N. Y. Cleveland, Ohio New York, N. Y. Chicago, HI. - Fall Meeting 474 June 26-29 June 26-28 June 24-27 Judc 22-25 June 27-29 June 22-24 June 20-22 June 16-19 June 22-24 June 24-26 June 20-23 July 4-6 ' Oct. 30-31 June 17-19 Oct. 14-15 June 17-19 June 15-17 June 7t-8 June 19-20 None June 10-13 June 1-4 June 20-23 June 20-22 Place Chicago, HI. Chicago, Dl. Milwaukee, Wis. Niagara Falls, N. Y. Indianapolis, Ind. St. Louis, Mo. Chicago, 111. Detroit, Mich. Buffalo, N. Y. Cleveland, Ohio Atlantic City, N. J. Detroit, Mich. Chicago, Dl. Buffalo, N. Y. Pittsburgh, Pa. St. Louis, Mo. Cleveland, Ohio Buffalo, N. Y. Detroit, Mich. - Chicago, 111. Kansas City, Mo. Atlantic City, N. J. Lexington, Ky. White Sulphur Springs, W. Va. West Baden, Ind. Bigwin Inn, Ont. Minneapolis, Minn. Swampscott, Mass. Milwaukee, Wis. Detroit, Mich. - Buck Hill Falls, Pa. Toronto, Ont. Buck Hill Falls, Pa, Swampscott, Mass. Hot Springs, Va. ' Mackinac Isl., Mich. Atlanta, Ga. Washington, D. C. Houston, Tex. San Francisco, Calif. St. Paul, Minn. Pittsburgh, Pa. Grand Rapids, Mich. Montreal, Que. (cruise) Coronado, Calif. Bretton Woods, N. H. Minneapolis,.Miim. ' Year 1950 1951 1952 1953 1954 1955 Annual Meeting Date 56th 57th 58th Jan. 23-26 Jan. 22-25 Jan. 28-30 59th 60th 61st Jan. 26-29 Jan. 25-27 Jan. 24-27 1956 1957 1958 1959 62nd 63rd 64th 65th Jan. 23-25 Feb. 25-28 Jan. 27-29 Jan. 26-29 * Regional Meeting Place Dallas, Tex. Philadelphia, Pa. St. Louis, Mo. Chicago, 111. Houston, Tex. Philadelphia, Pa. Cincinnati, Ohio Chicago, 111. Pittsburgh, Pa. Philadelphia, Pa. Semi-Annual Meeting June 19-21 July 2-4 June 16-18 June 29-Juiy 1 June 21-23 `April 14-16 June 27-29 June 18-20 . June 24-26 June 23-25 Place Muskoka Lakes, Ont. Portland, Ore. Spring Lake, N. J. Denver, Colo. Swampscott, Mass. Oklahoma City, Okla. San Francisco, Calif. Washington, D. C. Murray Bay, Que. Minneapolis, Minn. ASHVE AND ASHAE MILESTONES 1894-1959 1894. Organization meeting September 10, at Broadway Cen tral Hotel, New York, with 75 Charter Members. 1895 First Annual Meeting, January 22-24 at 12 West 31st Street, New York. Incorporation under laws of New York State, Transactions established. 1896 Society Emblem adopted at 2nd Annual Meeting--Dr. J. S. Billings, First Honorary Member. - 1897 First Semi-Annual Meeting held at the Windsor Hotel, New York, June 18. 1906 First Chapter organized in Chicago. 1907 Membership reached 301. 1911 Membership totaled 405. New York Chapter formed. Society established Headquarters in Engineering Socie ties Building, 29 West 39th Street, New York. 1914 Charter amended. 1915 Journal first published in April as a quarterly; later is sued monthly. 1916 Full time Secretary employed. 1918 Members in Armed Services--64. 1919 After several years of consideration and planning the Society established its Research Laboratory, in the United States Bureau of Mines, at Pittsburgh, Pa., having de termined a preliminary modus operandi and provided an operating fund. The Society is justly proud that it is the only professional engineering organization which main tains and operates its own Research Laboratory. 1922 The 1st edition of the ASHVE Gums published in September. - - 1923 Comfort Zone Established by ASHVE Research. 1925 Dues raised to $25.00 and 40 per cent of dues of Members and Associates allocated to Research Fund. 1927 Membership of Council increased from 12 to 17. 1928 Appointment of Technical Secretary and completion of Code for Minimum Requirements for Heating and Venti lation of Building*. Benjamin Franklin honored as Patron Saint of Society. ' 1929 Journal incorporated as a Special Section of Heating, Piping and Air Conditioning. Society Headquarters moved to 51 Madison Ave, New York, N. Y. 1930 Endowment created by Thornton Lewis for the F. Paul Anderson Medal. First International Heating and Venti lating Exposition held in Philadelphia. 1932 First Award of F. Paul Anderson Medal to Willis Havi- land Carrier. ' 1933 New Constitution and By-Laws adopted--Membership dues reduced. 1938 Membership passed 3000. 1941 Society requested to do Research for U. S. Navy. 1944 50th Anniversary celebrated in New York. 1945 Members serving in Armed Forces --416. 1946 New Charter approved. 1950 New By-Laws adopted January 26,1950. 1954 The name of the Society was changed to American So ciety of Heating and Air-Conditioning Engineers by vote of the members at a Special Meeting in New York, N. Y., November 22, effective December 8. / 1956 The Honorable Herbert Hoover, Dr. Milton S. Eisenhower and Dr. Charles F. Kettering* were elected Honorary Members. 1957 Dr. Arthur Cutts Willard elected an Honorary Member. 1958 Membership total of ASHAE 12,000. ' On December 1 the members of ASHAE and the ASRE, at simultaneous meetings held respectively in Chicago, QL, and at New Orleans, La., voted to approve an agree ment for consolidation. Deceased. 475 American Society of Heating and Air-Conditioning Engineers Headquarters: 62 Worth St., New York 13, N.Y. Tel. BArclay 7-6262 OFFICERS and COUNCIL 1959 President.................................................................................................... A. J. Hess First Vice President...................................................................... Walter A. Grant Second Vice President................................................................ John Everetts, Jr. . Treasurer....................................................................................................J. H. Fox Executive Secretary.................................. ..................................... A. V. Hutchinson Three years: William J. Collins, Jr., Harold A. Lockhart, George . W. Myers, Eolland S. Stover Two years: F. H. Faust, Fred Janssen, J. W. May, G. B. Priesteb ' One year: W. G. Hole, P. J. Marschall, E. R. Queer, W. O. Stewart, P. N. Vinther ADVISORY BOARD E. R. Queer, Chairman; Lester T. Avery, M. F. Blankin, S. E. Dibble, S. H. Downs, E. O. Eastwood, W. L. Fleisher, H. P. Gant, P. B. Gordon, John E. Haines, H. M. Hart, C. V. Haynes, L. N. , Hunter, John W. James, S. R. Lewis, A J. Offner, F. B. Rowley, L. E. Seeley, A. E. Stacey, Jr., Reg. F. Taylor, G. L. Tuve and A. C. Willard. COMMITTEE ON RESEARCH R. C. Jordan, Chairman ' ASHAE Research Laboratory, 7218 Euclid Ave, Cleveland 3, Ohio Director of Research........................................................................... B. H. Jennings Assistant Director of Research.......................................................C. M. Humphreys Assistant Director Industry Relations..................................................J. E. Loucks HEADQUARTERS STAFF Technical Secretary......... Editor............................ Public Relations Director. Assistant Secretary........ Technical Assistant. ............... Carl H. Funk ....... C. H. B. Hotchkiss ............. W. M. Vidulich Frederick W. Hofmann ........Carl W. MacPhee 476 DRY BUL8 TEMPEI 1 0 0 ____________ 105 110___________ 115 RATURE-FAHRENHEIT r> >- > DI C U.30 H 7)0 CD 5C > 5 X O Crt 5n 3* O o>> 0H< o ,nnz oZ-f<->j H ^z x<_o 52Gg >z> T> -Lz > *n X-- n 3h z-- o z 22 f?nz.C> > "D 2 o HnC piz _ _?.o Jr* *o Z01 PSgS 0 Z -- 1-- i?<r H o -oW sS SH -ns o "Jn0 J-l -n{ r _o oi? O 3J I> o OH q jjUl -j o' m o c o H </> *T| 5 o o co CO o X m co o -n > H m Z) o m x o o .0 2 .0 3 0 4 .0 6 .0 8 . 0 2 . 0 3 . 0 4 . 0 6 . 0 8 .1 .2 .3 .4 .6 .8 I 2 34 FRICTION LOSS IN INCHES OF WATER PER 100 FT