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I American Society of Heating and Ventilating Engineers Heating ventilating air conditioning guide. VOL 32 19 St 628.8 AMERICAN . 21718 78907 Heating i nd Ventilat: ng Engineer i No._ A406322 This Book Shall Not Be Taken From The Library- 0^ Heating Ventilating Air Conditioning Guide 1954 3rnv. irms r >- "< ?:-iSI .'0, S MA I'SVi .!<,! HEATING VENTILATING AIR CONDITIONING GUIDE A n Instrument ofService Preparedfor the Profession containing A TECHNICAL DATA SECTION of reference material on the DESIGN AND SPECIFICATION OF HEATING, VENTILATING, AND AIR CONDI TIONING SYSTEMS BASED ON--- THE TRANSACTIONS--- THE 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. Vol. 32 $10.00 per copy Published Annually by : The American Society oy Heating ' ' and Ventilating Engineers ` 62 Worth;St.. .. Mew York i3, N. Y. A406322 Copyright 1954 BY The American Society of Heating and Ventilating Engineers .. AND BY IT , Dedicated To the Advancement of The Profession ' '' AND ' ' ' " '' Its Allied.Industries 1 ' ` ' 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 Wavebly Press, Inc. BALTIMORE MARYLAND U. S. A. uA A 6 4SV? (\QFv PREFACE TO THE 32nd EDITION 4' jy The Heating Ventilating Air Condition Guide, 1954,which has 1128. pages of tech nical text, exceeds the previous edition by 32 pages. New features include a chapter on residential summer air conditioning, new data on methods of obtaining local relief in hot humid environments, recent developments in industrial air and gas cleaning, and many other changes made necessary by recent developments in the held. Wher ever possible, previous text has been condensed; the space saved has been used for additional new material and improvements. The previous grouping of the chapters in sections has been retained for the benefit of those who have become accustomed to previous section arrangement which is as follows: I--Fundamentals, II--Human Reactions, III--Heating and Cooling Loads; IV--Combustion and Consumption of Fuels, V--Systems and Equipment, VI-- Special Systems, and VII--Instruments and Codes. Some of the important changes will be found in the following chapters: Chapter 8--Air Contaminants. Tables of maximum allowable concentrations for gases, vapors, toxic dusts, fumes, and mists were reviewed and changed to agree with the latest recommendations of the American Conference of Governmental Hygienists.' Chapter 9--Heat Transmission Coefficients of Building Materials. Some new ma terial was added and a large part of the chapter was rearranged to improve the presen tation of the data. A table of U-value correction factors for outside wind velocity was added. Chapter 10--Water Vapor and Condensation in Building Construction. Actual de sign isotherms were added to the condensation zone map for guidance of owners, builders and architects. . Chapter 11--Infiltration and Ventilation. The section on Garage Ventilation was enlarged and improved. Data on individual car exhaust pipe sizes for repair shops and bibliographical references on garage ventilation were added. Chapter 12--Heating Load. The procedure for selecting outdoor design tempera ture was rewritten with greater discussion for sake of clarification. The data on edge heat loss from floor slabs were extended. . Chapter 18--Cooling Load. New data from recent A.S.H.V.E. research were added for effect of shading on instantaneous heat gain through window glass. . Chapter 14--Fuels and Combustion. The section on oil fuels was improved. Chapter 17--Chimneys and Draft Calculations. New information was added on draft requirements of appliances, operation of low chimneys, induced draft and general considerations for chimneys. . Chapter 24--Panel Heating. Illustrations, descriptions, nomenclature, arid instal lation suggestions were revised on the basis of recent experience with panel systems. Chapter 27--Pipe, Fittings, Welding. Several sections of the chapter were're written to conform to current descriptions and designations of pipe. New enlarged tables of steel pipe and copper tube characteristics were added. The data on pipe threading practice were revised. Chapter 28--Pipe Insulation. The information on application of insulation to pipe and fittings was enlarged in scope. * Chapter 29--District Heating. The chapter was enlarged by the addition of new information on. steam requirements of process equipment and of water heating, as determined by the National District Heating Association. Chapter 81--Air Distribution. This chapter was rewritten and enlarged by the Technical Advisory Committee on Air Distribution in consideration of the recent air flow research at the A.S.H.V.E. Research Laboratory and cooperating institu tions. The references and bibliography were revised to give a list of the most signifi cant articles and readily accessible papers, particularly those to be found in . A.S-H.V.E. publications. Chapter 84--Air Cleaning. Part I on Atmospheric Air Cleaners was revised and largely rewritten to cover recent developments and to agree with current industry nomenclature. Part .II on Industrial Air and Gas Cleaners was rewritten by the Technical Advisory Committee on Industrial Environment to conform to present practice in selection, installation; and operation of cleaners for industrial processes. New tables have been included to illustrate characteristics of industrial cleaners. Chapter 89-^-Automatic Control. The chapter was enlarged, largely rewritten, and rearranged to bring it up to date with recent progress. Several types of control not previously shown were included. A new section on coordination of controls was added. v V .V i, ^ *s- j\ . Chapter 4-rElectric} Heating."New material was added describing?types and features of Various systems, includingpanel systems. ; '; L Chapter 44--Owning and Operating Costs. The chapter was rewritten for the, pur pose of indicating items to be considered in determining first cost as well as operating cost of present systems. ` :V f v Chapter 45--Industrial Air Conditioning. A new section was added to illustrate methods of obtaining local relief for workers in hot humid environments. . . Chapter 50--Residential Summer Air Conditioning. This is a new chapter describ ing current practice in this rapidly developing application of air conditioning. Chapter 52--Codes,and Standards. Several standards were added to the previous list. References to codes were added or changed where necessary to indicate latest editions. Addresses of sponsoring organizations were brought up to date. . , In addition to the important changes enumerated, many others of a Jess extensive nature have been made to increase the .value of the.text, tables or illustrations.,. A twenty-four-page comprehensive subject index of the Technical Data Section follows the Table of Contents. A Catalog Data Section showing products, of .319 well-known manufacturers is included together with a detailed index for rapid refer ence to any desired type of equipment. . An Edge Index is a new feature enabling the users of The Guide to open the book immediately at . any . desired chapter of text or any. section of catalog data., : r The annual revision of The Guide is not only desirable but necessary in order to provide Guide users with the latest information on current practices in its field. A great number of suggestions received from readers are considered each year in order that new information may be added as soon as its usefulness and reliability can be ascertained. Members, other engineers, Society committees, associations, and various groups interested in heating, ventilating, cooling, and air conditioning re view current Guide.text continually,, and frequently submit complete revisions of existing material, or propose improvements for consideration of the Guide Committee* The Guide Committee expresses its appreciation to all of these sources for valuable assistance received in preparing this edition. A number of individual contributors who have been most active in preparing the 32nd Edition are given grateful recog nition: .. H. W. Altea' J. M. Black A. D. Brandt T. C. Brown F. N. Calhoon W. P. Chapman J. H. Clarke R. B. Engdahl Nathan Feder L. F. Flagg R, B. Foley J. W: Frazier W. F. Friend H. T. Gilkey ' R. A. GonzaLez - C. A. Gustafson T. F. Hatch . W. O. Huebneb C. M. Humphreys J. M. Kane G. E. Klapper S. R. Lewis P. J. Marschall J. W. McElgin G. E. McElroy L. A. Miles L. G. Miller G. V. Parmelee : F. J. Reed J. E. Seiter Leslie Silverman B. R. Small T. H. Smoot J. P. Stewart C. S: Stock G. L. Tuve R. P. Warren E. F. Wehlage W. N. Witheridge The Guide Committee takes pleasure in presenting The Guide 1954, which it hopes will be a most valuable reference book for practicing engineers, manufacturers, teachers and students. : = . ... GUIDE COMMITTEE . W. S. Harris, Chairman P. R. Achenbach D. L. Mills R. E. Cherne A. B. Newton A. L. Hesselschwerdt, Jr. F. J. Nunust, Jr. Carl H. Flinx, Technical Secretary C. D. Shields W. M. Wallace II - R. S. Dill, Ex-Officio CONTENTS . . Page Title Page............................................................... - - - - - = -: -......... ........ . ...... .. Preface..................................................... v -- -................ .:............ . Index to Technical Data...................."................----- : ..................................... *" v " SECTION I. FUNDAMENTALS -'. : - Chapter 1. Terminology..................................................... ................... ....... 1 2. Abbreviations and Symbols............ ....... ............................ 11 3. Thermodynamics ..... ....................................... ... 23 . 4. Fluid Flow......................... .................. ......... - .67 5. Heat Transfer............................................. ............. ........ . "6 SECTION II. HUMAN REACTIONS :- . Chapter 6. Physiological Principles .............................................. . 7. Air Conditioning in the Prevention and Treatment of Disease. 131 8. Air Contaminants.......................................... .... 151 SECTION III. HEATING AND COOLING LOADS Chapter 9. Heat Transmission Coefficients of Building Materials ------- - 167 ' 10. Water Vapor and Condensation in Building Construction ... 201 11. Infiltration and Ventilation.......217 12. Heating Load............................................................................. . 239 13. Cooling Load.......................................................... ;................... 265 SECTION IV. COMBUSTION AND CONSUMPTION OF FUELS Chapter 14. Fuels and Combustion............................................................... 321 15. Automatic Fuel Burning Equipment....................................... 357 16. Heating Boilers, Furnaces, Space Heaters....................... 385 17. Chimneys and Draft Calculations............................... .............. 411 18. Estimating Fuel Consumption for Space Heating................... 433 SECTION V. SYSTEMS AND EQUIPMENT Chapter 19. Gravity Warm Air Systems........................................................ 451 20. Forced Warm Air Systems...................... 461 , 21. Steam Heating Systems.................. 481 22. Hot Water Heating Systems....................................................... 523 23. Radiators and Convectors.......................................................... 541 24. Panel Heating.......... ......................................... 552 25. Unit Heaters and Unit Ventilators........................................... 575 26. Unit Air Conditioners and Unit Air Coolers.......... :............... 591 27. Pipe, Fittings, Welding...... .................... ................................. 605 28. Pipe Insulation............................................................................ 25 29. District Heating............. i.......... ................................................ 641 30. Central Systems for Air Conditioning...................................... 653 31. Air Distribution............... 667 32. Air Duct Design.......................................................................... 697 33. Fans...................................................... 733 34. Air Cleaning................................................................................. '51 35. Spray Apparatus............................................................................773 36. Air Heating and Cooling Coils............................. 799 37. Refrigeration.................................. 623 . 38. Dehumidification by Sorbent Materials.................................... ?61 39. Automatic Control..................................................................... 671 40. Motors and Motor Controls.................................... .................. 269 41. Sound Control............................................................................ 42. Electric Heating.......................................................................... 627 vii . CONTENTS (Concluded) SECTION V. SYSTEMS AND EQUIPMENT (Continued) Chapter 43. Corrosion and Water Formed Deposits, Causes and Prevention 945 44. Owning and Operating Costs....................................................967 SECTION VI. SPECIAL SYSTEMS Chapter 45. Industrial Air Conditioning....................................................... 977 46. Industrial Exhaust Systems............. ... ......... ................ 1003 47. Industrial Drying Systems.......... ............ ..............................1023 48. Transportation Air Conditioning............... .............................. 1051 49. Water Services............................................. 1067 50. Residential Summer Air Conditioning.................................... .1091 SECTION VII. INSTRUMENTS AND CODES Chapter 51. Instruments and Measurements................................................. 1099 52. Codes and Standards.......................... .......................................1119 edge Index . ; .... Modern Equipment............................................................................................ 1129 Technical Data............................... ,................................................................. 1130 CATALOG DATA,SECTION.................. ................ .............................................. 1131 . Index to Advertisers........ 1133 Index to Modem Equipment......... .................................. 1141 . Manufacturers' Catalog Data....................................... 1169 INDEX Heating Ventilating Air Conditioning GUIDE 1954 -. . TECHNICAL DATA SECTION CHAPTERS 1-52 and PAGES 1-1128 . Cross Reference to Subjects in Chapters 1-52 Alphabetically Listed 32nd EDITION viii INDEX HEATING VENTILATING AIR CONDITIONING GUIDE 1954 Technical Data Section Chapters 1"52 and Pages 1-1128 A Abatement air pollution, 151, 154 smoke, 8, 155, 326 -Abbreviations, 11 Absolute humidity, 5 pressure, 7 temperature, 9, 30 aero, 1, 30 . Absorbents, 861, 866 equipment, 867 process, 866 temperature, pressure, centration, 866 . con ' Absorbers, 769 duct, sound, 914 . outlet, 919 plate cells, 917 plenum, 919 Absorption systems, 839 Acceleration, 1 Acclimatisation, 118 Acoustics, 905 Activated alumina, 862 Activated carbon, 148, 1054 Activated bauxite, 863 Adiabatic, 1 mixing two air streams, 57 saturation, 60 Adsorbents, 769, 861. equipment, 865 process, 863 temperature, pressure, con centration, 861 Adsorption, odor, vapor, 156, 762 Aerosol, 1, 134, 151 Air change measurement, 1111 change method, 222, 256 chemical vitiation of, 111, 152,156 circulation, 112, 451, 461, 653, 697, 1052 circulation in dry, 1042 _ classification of impurities, 151, 752 dust, 151, 752 lint, 151, 752 cleaner, 151, 751, 1052 viscous impingement type, 753 cleaning, 751 cleaning devices, 751, 769, 770 charged media. 756 classification of, 751 electrostatic, 768 installation, 760 maintenance, 759 performance, 757 safety requirements, 761 selection, 759, 763 testing, 757 vapor adsorption, 762 combustion, 347, 348 conditioning process, 653, 977 Air {continued) contaminants, 111, 151, 164, 752, 1003, 1116 cooled condensers, 848 coolers, 597, 601 cooling, tropics, 136 current measurement, 1110 dehumidification, 861 distribution, 451, 461, 667, 669, 1052, 1058, 1061, 1096 air entrainment, 679 application of methods, 693, 1052 balancing.the system, 688 ceiling outlets, 685 definitions, 667 design methods, 715 directional control, 690 duct approaches to outlets, 453, 689 . entrainment ratios, 679 flow patterns, 689 friction chart, 698, 699 furnace systems, 451, 461 guide vanes, 462, 482 ' jet pattern, 681 long slot, discharge from, 677 noise level, 683 outlet location, 462, 463, 686, 692 outlet performance, 681, 687 outlets, 670, 684 perforated panels, 677 principles, 669 radial jets, 676 railway car, 1052 recommended velocity, 462, 714 return and exhaust intakes, 692 922 return 'grille, 451, 453, 922 room air motion, 669, 683 selection, 686 smudging, 684 spread, 668, 670 standards for, 668 throw, 675, 681 vanes, 681, 682 velocity, 577, 671, 714 velocity across jets, 672, 673, 675 velocity profiles, 675 vertical drop and rise, 682 volume control, 689, 691 wall outlets, 462, 684 duct construction, 722, 1015 duct design, 464, 697, 713, 724, 1010 duct friction loss, 697 dust concentrations, 155, 160, 161 excess, 330, 344, 348, 377 filter, 753, 760 flow measurement, 78, 1105 flow resistance of coils, 811 impurities, 113,151, 752 infiltration, 217 causes of, 218 due to wind pressure, 218 through walls, 218 leakage, 217-222 moist, 25 ' XI Air {continued) . motion, 122 movement, influence of, 117 movement, measurement of, 1105, 1109 outdoor, 112, 653 physical impurities in, 113, 151, 155, 752 pollution, 151, 155 ' abatement, 155, 326, 1003 primary, 328,`344 quantity required, 112, 347, 348, 1053, 1055 refrigeration cycle, 836 room motion, 669, 683 saturated, 1 secondary, 328, 344, 377 space conductance, 170, 180 standard, 1 sterilization of, 132, 142 . supply and return openings, 452, 463, 684, 692 supply opening noise, 683, 919 temperature requirements, 122, 126, 247, 266, 978, 988, 1061 theoretical requirements, 112, 346, 348, 1062 . thermodynamics of, 23 unit cleaning devices, 751, 773 washers, 1, 773 Air change method computing infiltration, 220, 255 Air conditioning, 1 aircraft. 1057 automobiles in summer,-1057 central system, 653, 1093 comfort, 2 hospitals, 131-148 humidity, table, 978 industrial, 977 atmospheric conditions re quired, 267, 978-988 calculations, 993 general requirements, 977 problem classification, 977 typical applications, 977 owning and operating cost, 967 passenger bus, 1056 processes, 54 adiabatic mixing , 57 adiabatic saturation, 60 cooling, 55 heating, 54 v railway passenger car, 1051 residential, 1091 ship, 1060 stoker-fired units, 358 storage systems, 841 streetcar, 1055 summer design conditions, 266, 267, 269 temperature table, 266, 269, 978 transportation, 1051 treatment of disease, 131 unit, 591 Heating Ventilating Air Conditioning Guide 1954 Air cooler. 501 units, 591, 601 defrosting, 602 design, 601 operation, 603 performance, 602 ratings, 602 types 1, 601 ' Air filters, 753 Air pollution, 154 control, 155, 326, 762 Air requirements, 112, 1053 Air supply opening noises, 683, 919 Air velocity, 462, 577, 669, 714, 1004,1006 cooling towers, 788 design, 714 residual, 666 unit heaters, 577 Air washer, 1, 773, 775, 777 Airborne matter, 152, 752 Airborne infection, 132,164 control, 132, 184 Airfoil fan, 733 * Aircraft air conditioning, 1057 Allergic disorders, 144 apparatus, 144 asthma symptoms, 145 hay fever symptoms, 144 . limitations of air conditioning ' methods. 145 Altitude, pressure and tempera* ture, 63 Anemometer, 1,1108 deflecting vane, 1109 propeller, 1108 revolving vane, 1108 thermal, 1110 Anesthetics, 138 Anthracite coal, 322, 323, 324, 325 firing methods, 325 Apparatus dew-point, 266, 309 Aspect ratio, 1, 667, . Asthma symptoms, 145 * Atmosphere, standard, 63 Atmospheric , conditions for industrial proc esses, 078--988 cooling towers, 783 mke-up water, 797 winter freezing, 798 , Atomizing humidifiers, 777 . Atomizing oil burner, 365 Attenuation, 913 ducts, 913 duct branches, 913 elbows, 913 grilles, 913 Attic fans, 749 . location, 749 types, 749 temperature, 249 Automatic controls (see Controls), 467,580, 871 application, 874 purpose of, 871 . tvpes of, 871 fuel burning equipment, 357 viscous filter, 753 Automobile air conditioning, 1057 . Axial flow fans, 733 B Baffle, 1,375 Bare pipe heat loss, 625 Barometer, 1104 Basement *. coefficients of transmission, 185 Basement (continued) heat loss, 185, 251, 252 temperatures, 251 Basementless houses, 253, 477 Bernoulli equation, 68 Biochemical reactions control of rate of, 991 Bituminous coal, 322, 323, 326 firing methods, 326 Blast beater, 2 Blow, 2, 577 Body adaptation to hot conditions, 118 heat loss, 113,120 odor. 111 thermal interchanges, 119,120 Boiler, boilers, 385 capacity for unit heaters, 584 care, 398 cast-iron, 385, 394 cleaning, 398 combustion rates, 394 connections, 396, 508 Hartford return, 508 return, 508 sizing, 509 steam, 508 construction, 385 design, 387 efficiency, 390 erection, 397 - fittings, 396 furnace design, 387 gas-fired, 374. 396 selection of, 392, 396 gas-fired units, 374 conversions, 375 grata area, 395 heating, 385 heating surface, 2, 387 heat transfer rates, 387 horsepower, 2 hot water supply, 393, 1080 load, 393 maintenance, 397 oil-fired units, 368 operation, 397 output, 390 rating, 388, 391, 392, 395 rating codes, 388, selection of, 393 based on heating surface and grate area, 395- cast-iron, 3&4 estimated design load, 393 estimated maximum load. 393 gas-fired, 396 hot water supply load, 393. 1080 piping tax, 393, 622 radiation load, 393 steel, 386, 388, 394 warming up allowance, 393, 396 soot; 354 space limitations, 396 steel, 388, 394 stoker-fired units, 358 testing codes, 388 troubles, 397 types, 385 British thermal units, 2 Bucket trap, 512, 513 Building, buildings condensation, 201 heat transfer through surfaces, 186-197 infiltration, 217, 255, 256, 301 intermittently heated, 259 materials, heat transfer through, 170, 177, 183; 186, 252 multi-story, air leakage, 227 Burner, oil. 365 Bus air conditioning, 1056 xii By-pass, 2, 644 factor, 309, 311 c Calcium chloride, 861, 866 Calculated heat loss method, 239 Calorie, 2 Calorific value, 322,333,338,339, 346 Carbon activated, 148, 861, 1054 dioxide, 111, 158, 328, 336, 341, 343-353 monoxide, 158, 342-353 Cast-iron boilers, 385 Ceiling cooling units, 602 high, 247 ' outlets, 685, 1053 perforated, 686, 1053. unit heater, 576 Central air conditioning sys tems. 653 accessibility, 666 air quantity, 659 apparatus dew-point, 266, 309. 657 control, 653,871 cooling Load, 265, 657 corrosion, 960 - design procedure, 666 effectual temperature differ ence, 659 equipment arrangement, 653 656 equipment selection, 663 evaporative cooling, 661 . fan system, 2 features, 653 heating load, 239, 658 hamidity eontrol, 657 individual room control, 656 induction units, 660 high pressure type, 661 low pressure type, 660 location of apparatus, 665,1095 outdoor air, 653 , 657 , pre-cooling, 662 ' reheating, 654 . run-around, 662 selection, 663 sensible cooling, 662. storage capacity, 657, 658 summer only, 1093 year 'round, 653 ' . zoning, 654 Centrifugal compressors, 847 . -condensing unit, 847 fan, 733 Charcoal, 756, Chart ' .. air elimination, 493 . air flow unequal openings, 228 air flow and sound level, 921 air friction, 698, 699 axial jet velocities, 674 ...' chimney capacity, ' 415, 416, 418-423, 427 chimney draft, 415, 416, 418-- 421 chimney flow, 418-423,.427 coil temperature, 564 t color, 22 '' comfort, 126 compressor and coil perform ance, 859 correction for pipe roughness, 701 dehumidifier performance, 870 design temperature map, 246 disease frequency, 133, 134 draft required, 412 dry vs. wet weight, 1025 drying time. 1026, 1027 drying weight, 1026 dust particle size, 153 Index to Technical Data Section Chart (continued) economical thickness pipe in sulation, 638 edge loss, 254 effective diameter, 673 effective temperature, 124, 125, . 128, 127 elbow loss, 706, 707 entrainment ratio, 678 estimating surface' tempera ture, 198, 561 expansion factor, 81, 82 evaporation chart, 1039 fan characteristics, 738-740 fan sound level, 738-740, 911-- 913 fan system characteristics, 741 filter resistance, 766, 767, 768 firebox dimensions, 364 * flow coefficients, 79, 80 flow due to wind, 225 flow through opening, 228, .229 flue area, 234 flue loss, 343 friction air ducts, 698, 699 friction factor, 71 friction in pipes, 525, 527, 1070-1072 fuel consumption, 381, 382 fuel oil index, 336 gas vents, 427 - head due to temperature, 524 heat flow, glass, 290 - heat emission by radiation from panels, 557 heat endurance, 119 heat loss body, 115, 116, 120,121, 122 canvas surface, 632 coefficients, insulated ducts. . 728 _ convection from panel, 559 duct, 728 floor, 255 insulated pipe, 629-632, 635 insulation, 628, 629-631 humidity, 1036 infiltration, 219 . . . inside surface temperature, 561, 562 ,. insulation of cold pipe, 635 ~'i Langelier formula, 954 moisture loss from body, 122 motor characteristics, 894-897 5TRT elevation, 119 orifice coefficient, 77 orifice installation, 83 panel heat output, 557, 559. 560 permissible relative humidi ties for various transmis sion coefficients, 203 pressure loss in ducts, 698, 699 pressure loss in elbowB, 706, 707, 709 pressure loss in faucets, 1073 pressure loss in meters, 1073 psychrometric charts, 53, 1037 persons at rest, 124 pump performance, 534 radial jet velocities, 674 radiation between - black bodies, 99 radiation shape factor, 98 refrigerant pressure-enthalpy, 826, 828 refrigeration horsepower, 975 room absorption correction, 923 solubility of calcium salts, 951, 952 solubility of gases, 950 sound attenuation, 917 static deflection, 925 . static regain, 719, 720 system characteristics, 741 temperature in panel, 564 thickness pipe insulation pre vent sweating, 635 velocity and velocity head, 705 Chart (continued) vena contracts location, 85 viscosity, air, 69 viscosity, water, 70 well water temperatures, 778 Chemical, chemicals laboratory hoods. 1006 , reactions* 988 ' control of rate of, 989 vitiation of air. 111, 156 water treating, 953, 956, 963 Chimney, chimneys, 411 available draft, 413, 418 construction details, 428 determining sizes, 416, 423 effect, 2 efficiency, 421, 422 factors affecting draft, 412 gas heating, 426 general considerations for, 405. ' 430 . industrial, 413. 416 performance, 411, 415, 416 residential, 417, 418 short, 420, 422 . sizes, 416, 423 static draft, 412 theoretical draft, 411 Cinders, 152 Circular equivalents of rec tangular ducts, 701 Circulators, 534 Cleaning boilers, 398 Climatic conditions, 241, 269 Closed expansion tank, 536, 537 sizing formula, 537 Coal, coals anthracite, 322-325 bituminous, 322, 323, 326-330 classification of. 322 combustion, 325 draft required, 329, 412 dustless treatment, 324 estimating consumption, 433. 444 firing methods. 325 lignite, 323 Codes, 1119 . installation, 1119 rating, 1119 testing, 1119 Coefficients of transmission, 5, 100, 181-197, 625, 813 basement, 251 floor, 192, 251-253 wall, 251 . coils, 544, 629, 813 doors, 197 floors and ceilings, 191, 192 frame construction, 186, 190 glass, 197 $lass block walls, 197 insulating materials, 182 masonry partitions, 190 masonry walls, 188 overall) 181 formulas for calculating, 181 roofs, 193-196 skylights, 197 windows, 197 Coil, coils. 799 air flow resistance, 811 applications, 805 arrangement, 802, 810 by-pass factor, 309, 311 construction, 800 cooling, 809, 818 dehumidifying, 809, 815 direct-expansion, 802 dry cooling, 593, 661, 813 film coefficient, 816, 817 flow arrangement, 804 heat emission, 544, 813, 1084 heat transfer surface, 811 heating, 808 ' xiii Coil (s) - (Continued) performance, 813, 815 cooling, 813 dehumidification, 815 heating, 813 pipe, 544 rating, 809 selection. 807. 818 cooling, 809, 818 dehumidifying, 809 heating, 808 steam, 801 uses, 799 water, 802' Coke ' classification of, 324 estimating consumption, 444 firing methods, 327 Cold therapy, 143 Color, piping systems, 22 Combustion, 321 adjustments, 362, 369, 377 air required, 347 analysis, 348 chamber, 363, 371 dew-point, 354 efficiency, 348, 370 flue gas, 348, 350 gas, 340 heat balance, 351 . heat of, 345 * index, 335 . losses, 352 oil, 334 process. 359, 377 principles of, 342 rates, 381, 382, 412 smokeless, 326 Comfort - . . air conditioning, 2 air conditioning systems, 653. 1051 chart, 126 line, 2 zone, 2 Compartment dryer, 1044 Compressor, compressors, 845 centrifugal, 847 clearance, 835 reciprocating, 845 refrigeration,7 performance of. 856, 857 rotary, 846 volumetric efficiency, 835 Condensates, 958, 959 Condensate return pumps, 510 Condensation buildings, 201, 215 concealed, 209, 210 control, 211 flue gas, 353 interstitial, 209 surface, 202 visible, 202 Condensers, 848 air cooled, 848 design data, 790 evaporative. 848 water coolea, 848 Condition line, 59, 311 . Conductance, 3, 167, 170, 180 air space, 170, 178 building materials, 171,180 insulators, 174, 180, 628 soil, 169 surface, 177, 797 Conduction. 3, 89 drying methods, 1042 electric heaters, 927 equation, 90 steady-state solutions, 101 Heating Ventilating Air Conditioning Guide 1954 Conductivity, 3. 89, 174, 180 bat type insulation, 174, 180 building boards, 174,180 building materials, 174,180 homogeneous materials, 169 insulating materials, 174, 175, 180, 181, 628 insulation blankets, 174,180 insulators, 174, 180, 628 loose-fill insulation, 175, 180, 187 masonry materials, 171,180 plastering materials, 173,180 reflective insulation, 170,180 rigid insolation, 175,180 roofing construction, 173, 184 soil, 176, 177 woods, 173, 181 . Conductor, 3 Conduits for piping, 643 Connections boiler, 396, 508 heating units, 520 Control, controls absorption units, 880 actuated, 873' actuating, 872 adsorption units, 880 airborne infection, 132 all-year conditioning, 654, 877, 882 application, 874 automatic, 467, 871 fuel appliances, 357, 875 temperature, 872 basic types, 871 central fan system, 653, 880 all-year system, 653, 881 heating cycle, 656 coal-fired plant, 875 compressor, 852, 880 cooling units, 879 damper operator, 874 dehumidification, 879; 880 dehydrating equipment, 865 desigo, 887 designation, 871 draft, 329 . electric heating, 875 electronic, 885 equipment for motors, 900 fan, 744,880 gas burner, 875 gas-fired appliances, 875 heating unit, 875 hot water heating, 878 hot water supply, 1085 humidity, railway cars, 1054 ice bunker, 880 indicating, 873 individual rooms, 1064 limit, 876 modulating, 871, 877 motor, 889 oil burners, 875 panel heating, 883 circuit balance, 884 inertia, 883 night temperature, 884 typical systems, 885 pneumatic systems, 871 _ rate of biochemical reactions, 991 rate of chemical reactions, 989 rate of crystallisation, 991 recording, 873 refrigeration equipment, 850, 879 compressor type, 880 ice cooling, 880 well water, 880 regain, 988 . relay, 874 residential systems, 875 room, 886 ' room thermostat, 876, 886 safety, 853 service water temperature, 1085 ship control, 1064 single phase motor, 901 Control(s) (continued) solenoid valves, 852 sound, 905 . squirrel-cage motor, 900 steam heating, 877 steam jet system, 880 stoker, 365, 875 system, 877 temperature, 871 terminology, 871-874 thermostats, 872 two-position control, 871 types, 871, 872 unit cooler, 879 . unit heaters, 878 unit systems, 877, 878, 879 unit ventilators, 879 . valves, 521, 621, 873 ventilator, 231 volume, 689 warm air system, 876 well water, 880 zone, 677, 886 Controllers, 871 functions, 871 types, 871 Convection, 3, 89, 99 equation, 91 unit conductances, 94 Convector, convectors, 3, 541, 545 correction factor, 546, 548 heat emission, 548 heating effect, 548 induction, 660, 661 ratings, 546 Converging vanes, 682 Conversion burners, 375 equations,-15, 207 Coolers, 591, 601, 849 Cooling. 265, 584 air conditioning units, 591, 1094 atmospheric water, 773 coil selection, 807 evaporative, 661 load, 265, 657 methods, 479 performance of coils, 813, 815 ponds, 781 residential, 479, 1094 sensible, 662 spray. 779 , 781 effect of wind, 782 make-up water, 797 size of equipment, 783 winter freezing, 798 systems, 479, 653, 1052, 1056 towers, 780 atmospheric, 783 design, 789, 790 mechanical, 785 operation. 797 performance. 792 selection, 795 units, 591 component parts, 592 control, 598 . definitions, 591 defrosting, 602 design, 592 performance, 591, 599 ratings, 598, 602, 603 remote, 596 _ sound isolation, 595 types of, 601 water, 781, 788 water piping, 1076 Copper elbow equivalents, 525 Copper tube dimensions, 608 Core area, 667, 1109 Corrosion, 607, 945 air duets, 961 atmospheric, 960 boilers, 952, 961 cathodic protection, 963 coal storage equipment, 961 Corrosion (continued) cold water, 956 condensates, 948, 958, 959 flue gas, 353 flues, 961 heating systems, 952 hot water, 957 industrial exhaust systems, - 1018 . , minimizing condensate, 958 pipe, 962 prevention, 953, 1020 refrigerating systems, 957 underwater, 955 Cost of air conditioning, 967, 1096 amortization, 967 condenser water, 974 first, 967 fixed charges, 967 ' heating, 976 interest, 970 installed, 968 insurance, 971 labor,972 maintenance, 971 owning and operating, 973 rent, 971 service, 971 taxes, 970 refrigeration equipment, 973 - water, 972 Crack length ` method, 219 used for computations, 256 Crysta llization control rate of, 991 - , Cylinder dryer, 1044 D Dalton's rule, 28 ' Damper, dampers, 330, 463, 653, 685,873 Darcy formula, 69 Decibel, 905 Definitions, 1 Defrosting, 602 Degree-day, 3, 437 for cities, 439, 448 *. formula for, method, 438 industrial, 448 , 449 operating unit, 446 unit fuel consumption, 444 Degree of saturation, 8, 25, 31 Dehumidification, 654, 777, 861 . air conditioning units, 596 air washers, 777 coil selection, 799 , 809 comparison of methods, 861 control, 865 definitions and methods, 861 equipment, 777, 861, 865 performance, 864 estimating loads, 868 liquid methods, 866, 867 moisture load, 868 ships, 1063 solid methods, 863, 865 vapor transfer, 870 Dehumidifying agents, 861 sorbents, 861 absorbents, 861 - adsorbents, 861 Density of air, 1 Design conditions summer, 266, 269 winter, 241, 247, 248 Dew-point apparatus temperature, 265, 309 flue gas, 354 , 961 temperature, 9, 26, 1112 Dichlorodifluoromethane, 825 827, 854 , 855 D ielectric heating, 941 XIV Index to Technical Data Section Direct expansion coils, 802 fired unit heater, 575 indirect heating unit, 3 radiator, 7 return system, 3, 530 Disc fan, 733 Distribution of air (see' Air Distribution), 451, 461, 658, 667, 1052, 1058 District heating, 641 glossary of rate terms, 651 meters, 647 piping, 639 conduits for, 643 inside, 645 overhead distribution, 645 sizes, 641 tunnels, 645 rates, 649 steam requirement, 649 Diverging vanes, 462, 682 Domestic oil burners, 365 Door, doors coefficients of transmission, 197 leakage,219, 221 natural ventilation, 230 Down-Feed one-pipe riser, 3, 6, 483 steam heating, 3, 489 system, 4, 481 Draft, drafts, 4, 411 available, 413, 418 calculations, 411 chimney , 411' . control, 330 . factors, 412 general equation, 411 head,4 industrial chimneys, 413 mechanical, 411 - . natural, 217, 411 regulation, 329 residential chimneys, 417 requirements, 329, 412, 425. 426 appliances, 426 theoretical, 411 Drawing symbols, 17 Drip, drips, 4, 483,517 Drum dryer, 1044 Dry air, 1 composition, 25, 345 filters, 755 properties of. 30 velocity bead, 705' Dry-bulb temperature, 9 Dry cooling coils, 799, 813 Dry return, 8, 481 Dryer, dryers, 1042 cabinet, 1044 calculations, 1038 compartment, 1043, 1044 cylinder, 1044 drum, 1044 rotary, 1044 spray, 1045 tunnel, 1044 Drying. 989, 1023 application of hygrometry, 1037 calculations, 1038 chart, 1037, 1039 conduction, 1043 constant rate period, 1027, 1029 convection, 1043 critical moisture, 1034 effect- of air velocity, 1028 equations, 1034 equilibrium moisture, 1035 equipment, 1042 example, 1046 external conditions, 1025 factors influencing, 1024 falling rate period, 1031 . internal conditions, 1025 Drying (continued) mechanism of, 1(324 methods, 1042 conduction, 1043 convection, 1043 radiant, 1042 periods, 1026 problem, 1046 radiant, 1042 surface temperature, 1028 systems, 1023 terminology, 1023 Duct, ducts, 453-455, 464, 689 air velocities in, 462, 714. 1006, 1014 approaches to outlets, 689 area change, 708 attenuation, 913, 917 circular equivalents, 701 construction details, 722, 1015 design, 453, 464, 714, 715, 1010 design methods, 715 equal friction, 716 static regain, 718 velocity reduction, 715 dynamic losses, 702 elbow friction losses, 706 exhaust design; 1010 friction losses, 697 heat loss coefficients, 725, 728 lining, 916 maintenance, 729 measurement of velocities. 1105 noise transmitted, 908 pressure changes, 711 pressure loss, 697, 706 recirculating, 453, 455, 463, 692 rectangular equivalents of round, 428, 701 resistance, 697 roughness correction, 701 sizing, 688, 717 sound absorbers, 914 ' symbols for drawing, 17 system design, 453, 464, 697 weight, 724, 725 Duct sizing, 688 equal friction method, general rules, 454, 464, static regain method, 718 velocity method, 715 - 716 715 Dust, 4,151 combustible, 161 concentrations, 155 determination, 154 filters, 751, 760, 766 precipitators, 755, 768 removal, 751 size, 153 Dust collectors. 751, 762 application, 751, 760, 764 centrifugal, 765 cyclone, 766 cloth, 766 degree of dust removal, 763 electrostatic, 768 fabric, 766, 768 factors affecting selection, 763 inertial separators, 765 settling chambers, 768 scrubbers, 765, 767 testing methods, 755 types, 764 wet, 765 centrifugal, 767 packed tower, 767 spray towers, 767 washers, 767 wet filters, 767 Dynamie head, 5, 702 losses, 702 E EDR (Equivalent direct radia tion), 7; 393, 492, 496, 498, 500, 541 defined, 7, 393, 541, 546 XV Effective temperature, 9, 122 chart, 122,128 index, 122 Efficiency boiler, 390 conversion burner furnace. 404 seasonal, 434 Ejector nozzles, 685 Elbow attenuation, 913 copper equivalents, 525 friction losses, 497, 525, 706. . 707 iron equivalents, 497, 525, sheet metal, equivalent, 455 468, 706, 707, 709 Electric, electrical baseboard, 931 control systems, 861 - convector, 931 demand control, 942 dielectric heating, 941 heat applications, 928 heating, 927 calculating capacities, 939 central, 934, 935 control, 929,933 domestic water, 938 equipment, 927 heat pump, 935 induction, 941 power problems, 941 resistors, 8, 927 systems, 929 units, 928 hot water heating, 934 induction heating, 941 installation methods, 929 motor design limits, 890 . panel heating, 556, 932, 933, 934 precipitators, 755, 768 radiant convector, 931 radiant heating, 556, 931 resistors, 927, 932 steam radiator, 932 systems, 889, 929 voltage ratings, 890 Electricity, static, 139, 992 Emisaivity, 95,170 Enclosed radiator, 551 Enthalpy, 4, 24, 30, 51 free, 4 specific, 4, 30 Entropy, 4, 30, 51 mixing, 51 Equivalent evaporation, 4 Estimating fuel consumption, 433 Eupatheoscope, 1114 Evaporative condensers, 848 . cooled, unit conditioners, 591 cooling, 661 Evaporators, 849 Excess air. 330, 344, 348, 377 Exhaust opening, 692, 1004,1014 measurement of velocities. 1020, 1109 Exhaust systems, (industrial) 1003 air flow equipment, 1016 axial velocity formula, 1004 capture velocities, 1004 construction, 1015 conveying velocity, 1014 corrosion, 1020 duct construction, 1015 duct design, 1010 duct resistance, 1010 duct system design, 1010 duct velocity, 1006 ducts for, 1010 air velocities in, 1006, 1014 construction, 1015 design, 1010 resistance, 1011 Heating Ventilating Air Conditioning Guide 1954 Exhaust systems (continued) dust filters, 1017 elements, 1003 equipment, 46 exhaust requirements, 1005 Sineral requirements, 1003 oods, 1003, 1006 . air flow, 1005 air velocity, 1004 velocity formula for, 1004 - canopy, 1006-1009 capture velocities, 1004 chemieal laboratories, 1007 design principles, 1003 kitchen, 1007 large open, 1006-1009 ^ special exhaust require ments, 1005 spray booths, 1009 suction, 1017 velocity contours, 1005 ventilation rates, 1006-1013 make-up air, 1017 maintenance, 1017 materials, 1015, 1018, 1019 performance, 1017 pressure loss, 1013 resistance of, 1013 specifications, 1015 suction requirements, 1013 types of fans, 733, 748 velocity contours, 1005 velocity requirements, 1006 1009 Expansion factor, gases, 81, 82 of pipe, 520, 610, 611, 612 tank installation, 539 tank piping, 536 tank size, 537 tanks, 536 ' valves, 851 Explosion hazard, 138 Extended plenum systems, 459 F Fan, fans, 733 application, 747 arrangement of drives, 742 attic, 749 location, 749 axial flow, 733 centrifugal, 737 characteristic curves, 738-740 control, 744 designations, 734 drive position, 744 efficiency, 737 exhaust, 746 furnace system, 461 hot gas, 750 installation, 747 kitchen, 749 laws, 735 marine, 748 mine, 748 motive power, 745 noise generated, 908, 910 performance, 733, 737 radial Bow, 733 rotation, 743 selection of, 745 air conditioning systems, . 745 industrial exhaust systems, 1016 special application, 749 speed, 746 system characteristics, 741 types, 733 unitary systems, 748 velocity, operating, 746 volume control, 744 Fanning formula, 69, 569 Fever therapy, 142 equipment for production of, Film conductance, 92, 167, 168, 179, 816, 817 Filter, filters, 751 . air -conditioning units, 5% atmospheric, 751 charged media, 756 dry air, 755, 766, 1056 dust, 755 installation, 760 ionizing, 755 maintenance, 759 moving curtain, 754 performance, 757 selection, 759, 763 ' ' testing, 757 vapor adsorption, 769 viscous impin-ement type, 753 Fittings allowance, 455, 470, 497, 525 pipe, 497, 525, 613, 1074, 1075 sheet metal, 455, 459, 470, 706, 709 Flash leg, 613 Flexible mountings, 407 Float trap, 512 Floor . cooling unit, 591 heat transfer coefficients, 191,192 panel design, 561 unit heater, 575 Floor slab heat loss, 252 Flow coefficient, orifices, 77 compressible fluids, 73 critical, 76 measurement head meters, 78, 83 liquids, 78 orifices, 78 Pitot tube, 84,1105 variable area meters, Flow meters, 78, 647, 1074 Flue gas analysis, 350 Flue gas dew-point, 354, Flue gas loss, 351 Fluids, flow, 67 theory, 67 Fluid meters, 78,647 Fog, 4,152 Force, 4 Forced air beating system, 461 circulation pipe sizes, 530 convection, 92, 93 Free convection, 92,94 enthalpy, 4 Freezing in pipes, 635 86 Friction loss air ducts, 478, 697 . circular pipes, 69 effect of area change, 708 elbows, 455, 470, 497, 525, 706, 1074, 1075 gas piping, 378 non-circular pipes, 72 refrigerant piping, 853, 854, 855 water heating, 525-527 water piping, 525-527, 1072, 1074 Fuel, fuels, 321 analysis, 321, 331, 338 burning equipment, 357 classification, 321, 324, 330, 339 consumption, 433 calculated heat-loss method, 435 degree-day method, 437 load factor, 449 mAxitrmm demands, 449 seasonal efficiency, 434 unit, 442-446 firing methods, 325, 326, 327 gas, 337 liquid, 330 solid, 321 unit consumption, 444 utilization, 400 Fuel oil, 330 . analysis, 331 carbon residue. 332 classification of, 330 combustion of, 334 flashpoint, 332 grade of, 333 maximum carbon dioxide values, 349 - eg theoretical air requirements, 347 viscosity, 332 Fumes, 4,151 Furnace, furnaces, 4, 399 capacity, 401 casings, 405 cast iron, 401 combustion rate, 400 design, 387, 404 efficiency, 404 fan, 400 filters, 400 forced warm air, 400 gas-fired units, 379, 404 grate area, 403 gravity warm air, 399, 402 beating surface, 402 heavy duty, 400 humidification equipment, 405 materials, 401,406 mechanical warm air, 400 controls, 467 cooling methods, 479 cooling system, 479 dampers, 463 ducts, 463 fans, 400 - filters, 400 method of designing, 404 motors, 400 ratings, 401 oil-fired units, 400 rating, 401, 403 steel, 401 stoker-fired units, 358 types, 399 volume, 4, 330, 364 , 371 warm air, 399 G Gage, gages draft, 1104 pressure, 7,1103 Garage ventilation, 236 Gas, gases, 152, 158, 337 appliance rating, 379 atmospheric, 152, 164, 949 burner controls, 876 burners, 375 calorific value, 339 chimneys for. heating, 426 classification of, 339 combustion of, 340 equipment, commercial, 380 equipment, industrial, 380 estimating consumption, 443 expansion factor, 81, 82 flammable, 157 flue, 348 heaters, 409 pipe size, 378, 380 solubility, 932 space heatera, 376, 409 specific heat, 5 wall heaters, 377 Gaseous fuels, 337 calorific value, 339 classification of, 338, 339 combustion of, 340, 377 maximum carbon dioxide values, 349 products of combustion, 344, 346 properties of, 338 specific gravity, 338 theoretical air requirements. 346, 348 typical analyses, 338 Index to Technical Data Section Gas-fired appliances, 374 ' boilers, 374 - - , combustion process, 377 controls, 875 conversion burners, 375 furnrces, 375 measurement of efficiency of combustion, 377 pipe size, 3S0 ratings for, 378 sizing heating plants, 379 space heaters, 376 Glass coefficient of transmission, 196 design tables, 289, 295 heat absorbent, 292 shading of, 298 solar heat transmitted, 287. 293 window transmittance, 288 Glass block walls coefficient of transmission. 197 solar heat gain, 294-297 Globe thermometer, 1114 Graphical symbols for draw ings, 17 air conditioning, 17, 21 duct work, 19 beating, 17,18,19 piping, 17 refrigerating, 21 ventilating, 19, 20 Grate area, 5, 395, 402 Greek alphabet, 14 Grille, grilles, (see Registers), 451, 453, 462, 667, 684 air supply noises, 919 attenuation, 913 exhaust, 453, 692 locations, 453, 686, 692 door, 693 floor, 693 wall, 693 mechanical furnace Bystems. 462 noises, 692 railway car, 1053 recirculating, 1053 return, 451, 453, 692, 922 selection, 920 velocity, 462, 692, 922 Ground temperatures, 250 Guarded hot plate, 2113 Gun type oil burners, 365 H Hangers pipe, 612 Hartford return connection. 483, 508 Hay fever symptoms, 144 Health, 131, 993 Heat, 5 area transmitting surface, 1083 auxiliary sources, 258, 304 balance, 351 combustion, 322, 339, 345, 346 emission of appliances, 306 occupants, 120-122, 304 pipe coils, 544 exchange' measurements, 114 flow resistance, 99, 167 flow through glass, 197, 287 flow through roofs, 181, 193 196, 280, 284 flow through walls, 187-190, 282, 284 gain, 265 generated by motors, 305 humid, 5 infiltration equivalent, 301 instantaneous load, 273, 299 Heat (continued) introduced by outside air, 301 lag, 658 latent, 5, 257. 265, 274, 303, 304, 305, 308, 315, 317, 654, 866 liquid, 5 loss, pipe, 666 , mechanical equivalent of, 6, 15 methods of, transfer, 89 radiant, 92, 95, 96, 541 ratio, sensible, 309 removal, natural ventilation, 225 * sensible, 5, 256, 265, 274, 303, 304, 306, 311, 316, 666 specific, 5 transfer, 89, 187-197, 541, 625, 725, 811 boiler rates, 387 overall coefficients, 99, 167, 168, 180-197, 542, 813, 1083, 1084 surface coils, 808 symbols, 12, 95,167 through building materials, 167 water coils, 1084 Heat gain, 365 appliances, 306 ceilings, 301 ' components of, 265 ducts, 659. 725 electrical heating equipment, 306 floors, 301 . gas burning equipment, 308 glass, 287 glass blocks, 294 infiltration, 301 instantaneous, 300 latent, 274, 302 lights, 304 moisture, 305 occupants, 304 outside air, 303 partitions, 300 people, 120, 304 roof, 278, 284 sensible, 273, 302 shaded windows, 298 solar, 292 steam heated equipment, 307 various sources, 259, 309 ventilation, 301 wall, 278, 282 Heat loss air change, 257 bare pipe, 544, 626 basement, 252 duct, 725 floor slab, 253 infiltration, 255 insulated pipe, 628 latent, 257 residence problems, 259 sensible, 256. 666 through Ceilings and roofs, 255 to sky, 187 transmission, 167,254 Heat pump, 824, 842, 843, 935 1089 Heat removal, 22? Heater, heaters direct-fired unit, 575 electric, 577,927 gas,409 design, 410 ' efficiency, 409 materials, 409 rating, 408 testing, 408 oil, 407 design, 409 materials, 408 rating, 408 testing, 408 ' ' xvii Heater(s) (confirmed) solar water, 1087" ' solid fuel, 406 design, 407 material, 406 rating, 406 testing, 406 space, 406 . installation, 410 unit,575, 928 vertical blow unit, 576 ' Heating air conditioning units, 591 boiler8,385 surface, 2, 387 coil selection, 807. district, 641 effect, radiator, 548 electric, 927 hot water, 938 load, 239, 311, 392, 658 performance of coils, 813, 1083 reversed cycle refrigeration, 843 steam systems, 481 surface, 9 square foot of, 8 symbols for drawing, 17 the radiator, 550 vacuum systems, 10, 481, 488 vapor, 10,486 : warm air system, 10, 451, 461 water, 523,1067 Heavy duty fan furnace, 400 High duty humidifiers, 779 High temperature hazards, 117,137 Hood, hoods, 1003 Horsepower, boiler, 2 . Hospital, hospitals . air conditioning in, 131, 147 operating rooms, 138 air conditions, 139 reducing explosion hazard, 138 sterilization of air, 132 ventilation requirements, 140 Hot water boiler supply load, 393, 1077 coil surface, 1083 demand per ' fixture, 1068, 1069, 1080 person, 1077, 1078 electric beating, 938 heat pump, 1089 heating surface, 1083 indirect beater, 1081 methods of heating, 1080 panel beating, 553 safety devices, 1088 service, 1067 ` . service piping. 1084 solar heaters, 1087 storage tank, 1077 supply boilers, 386,938,1080 piping, 1084 temperature control, 1085 Hot water heating systems. 5,523 . Circulation head, 523, 524, 531 classification, 527, 530 direct return system, 528 elbow equivalents, 525 expansion tank{ 536 forced circulation, 524, 527, 532 friction heads, 524 gravity, 527, 531 available head, 523 circulation; 523 pressure brads, 523 installation details, 539 mechanical circulators, 533 one-pipe forced circulation, 528. 531, 533 Heating Ventilating Air Conditioning Guide 1954 Hot water beating systems {continued) gravity circulation, 527, 531,533 orifice friction beads, 529 pipe sizes, 525-527 . forced circulation, 524 gravity circulation, 523 piping design, 530 pressure head, 524 relief valve, 540 reversed return system, 530 safety devices, 1086 systems of piping, 530 two-pipe forced, 528, 531,535 gravity, 526, 531, 534 zoning, 540 Human body acclimatization, 118 adaptation. 114 . cold condition, 115 hot conditions, 115 heat emission, 120, 304 high temperature hazards, 117 metabolic rates, 116 odors, 117 temperature, 114 thermal interchanges, 113 zone of evaporative regula tion, 115 Humid heat, 5 Humidification. 595, 775, 780 control, 472 , 880 direct, 777 forced furnace systems, 405 Humidifier, humidifiers air washer, 773 atomizing, 779 high duty, 779 self-contained, 780 spray, 780 unit, 780 Humidistat, 5 Humidity, 5 absolute, 5 control, 657, 880, 1054 infiuence of, 122,141 measurement of, 1111 nurseries for premature in fants, 140 ratio, 5, 25 relative, 5, 25,665 Hygrometers, 1112,1113 Hygroscopic materials, 988-990 Hygrostat, 5, 872 I Ice systems, 841 Impulse trap, 514 Incn of water, 5 Induction units, 660 high pressure types, 661 low pressure types, 660 Industrial air conditioning, 977 calculations, 993 conditioning and drying, 989 contaminant control. 993 control of chemical reac tions, 989 dilution systems, 994 general requirements, 977 humidities, 978-988, 991 laboratories, 992 . local relief, 995 machining tolerance, 992 moisture content and re gain, 988 polished surfaces, 992 process, 977 safety, 993 static electricity, 992 temperatures, 978-988 exhaust systems, 1003 Infiltration ' . causes, 217 due to wind pressure, 218 heat losses, 255 - latent, 257 sensible, 256 measurement. 1111 temperature differences, 223 through outside doors, 222 through walls, 218 through windows, 220 . Inflammability, 162 Inside temperature, 247, 248, 266 Instruments, 1099 Insulation, 6, 625 economical pipe thickness, 637 Eavity furnace duct, 451 w temperature pipe, 634 pipe, 626 _ pipes to prevent freezing,.635 sound, 905 _ underground pipe, 639 _ Intermittently heated build ings, 259 Isobaric, 6 Isothermal, 6 j Jets, 669 expansion, 671 radial, 676 velocity, 671 Joints, duct, 722 K Kata thermometer, 549, - 1110 L" Laboratories, 992 Latent beat, 5, 257, 265 loss, 257 Laws of thermodynamics, Leaders, 451 9 Leakage of air. 217 door. 219,221, 222 window, 219, 220, 301 Light heat gain, 304 Lignite, 322, 323 Liquid absorbents, 866 heat of, 5 _ Lithium bromide, 861 Lithium chloride, 861 Load cooling, 265, 653 design, 6, 265 factor, 450 ' heating, 239 , 658 maximum, 6, 393, 449 refrigeration, 265 M Machine vibration, 923 Manometer, 6, 1103 Marine {see ship heating, venti lating, air conditioning) Mass, 6 Mbh.526 Mean radiant temperature, 119, 560, 563,884 Meter, meters. 78 , 647 area, 78, 85 , 647 condensate, 647 differential, 648 flow, 78,85, 647 force, 78 head, 78 . 83 , 648 Nicholls* heat, 1114 orifioe, 80, 648 selection, 649 velocity, 648 venturi, 1108 Metering, liquids, 78, 647 . xviii Micromanometers, 1104 Micron, 6 Mist, 152 Moist air, 25 properties of, 32 saturation. 29 specific volume, 32 Moisture. 201,988 content, 988, 990 load, 868 loss per person, 122 , 304 ~ permeability, 204,206 regain, 990 Mol, 6 , Monoftuorotrichloromethane, 827 , 828-830 - Motor, motors. 259, 400, 889 alternating current, 893 capacitor type, 899 classification, 892 control, 900 control equipment for, 902 design limits, 890 drives, 892 electric, 889 enclosures, 903 glossary, 903 heat generated by, 259 hermetically enclosed, 898 multi-speed, 895, 901 polyphase, 893 rating, 901 .. repulsion induction, 897 selection, 889 single phase, 896 speed characteristics, 892, 894 speed classification, 904 speed ranges, 890 split phase, 897 squirrel cage, 892, 893, 900 synchronous, 894 , 900 wound rotor, 894,900 N Natural draft, 411 towers, 783 Natural ventilation, 225 Noise, noises. 905 absorptive material, 914 air conditioning system, 906, 1095 air supply opening, 919 apparatus for measuring, 906 attenuation, 913, 914 average in rooms, 910 - control. 906. , controlling vibration, 923 cross transmission between rooms, 922 . design room level, 909 . duct sound absorbers, 914, 916 duct system attenuation, 913 fans,910 - general problem, 906 grille, 920 intakes, 692 kinds of, 908 levels, 683, 909 loudness, 910 measurement, 905 openings, 919 plate cells, 917 _ plenum absorption, 919 through building construc tion, 922 transmitted through ducts, 908 typical sound level, 909 unit of measurement, 905 Nozzle flow, 75, 78 Nurseries for premature In-, fants, 140 , air conditioning equipment, 141 A -) v: Index to Technical Data Section Nurseries for premature in* fants {continued) air conditioning requirements, 141 o Odors. Ill, 113, 147, 156, 976 human body, 111 Oil Fuel, 330 * analysis, 331 calorific value, 333 , 334 classification of, 330, 332 ' combustion index, 336 combustion of, 334, 368 estimating consumption, 433 , heating of, 373 * piping, 373 storage, 373 . Oil burners, 365 atomizing, 365, 372, 373 boiler settings, 371 classification, 365, 372 combustion adjustments, 369 combustion efficiency, 370 combustion process, 368 commercial,- 372 controls, 372, 871 domestic, 365 furnace design, 371 gun type, 365 industrial, 372 _ . measurement of efficiency of combustion, 370 mechanical draft, 365 operating requirements, 368 rotary type, 366, 372 vaporizing type, 367 - One-pipe system. 482, 528, 532 Eivity air-vent, 483 t water, 528 steam, 6 supply riser, 6 unit heater connection, 4S2 vapor, 484 Opening, openings air supply noises, 919 stacks, 231 types of, 230 doors, 230 - roof ventilators, 230 skylights, 230 vertical, 224 . windows, 230 Operating rooms, 138 conditions, 139 reducing explosion hazard, 138 sterilization of air in, 140 Orifice discharge, 75, 492, 529 Sow, 75 . formulas, 77, 1107 heating systems, 490 Orsat apparatus, 1115 Outdoor air, 112, 653, 1052, 1056 Outlet, outlets air supply noises, 919 ceiling, 685 duct approaches, 689 location, 462, 463, 686, 688 performance, 687 selection, 686 side outlets, 462 sound absorbers, 919 types, 670, 684 wall outlets, 684 Outside temperature, 241-245, Overhead distribution, 487, 645, 1085 Overhead system, 487, 645, 1085 nbers, 142 tents, 142 therapy, 145 Ozone, 113 P Panel heating, 553 application methods, 553 calculation principles, 556 convection transfer, 558 design of panel, 561-565 electric. 556, 930, 932-934 embedded piping, 554, 571 hot water, 553 . installation, 565, 932 output from surface, 556, 559 piping, 553, 565 radiation transfer, 556 steam, 553 warm air, 477, 555 Panel radiator, 6 Particle size chart, 153 Perfect gas relationships, 27 Perforated ceilings, 686 Perforated outlets, 684, 686 Permeability, 204, 208 Permeance, 204, 206, 208 pH value, 950, 954 Physical impurities in air, 113 Physiological principles. 111 . acclimatization, 118 comfort chart, 126 effective temperature, 122 high temperature hazards, 117 thermal interchanges, 113 upper limits of heat, 119 Pipe coils, 544, 553, 571 heat emission, 544, 625 wall, 544 * Pipe, piping, 605 capacity, 494-506, 525, 1067 coatings, 962 coil connections, 520 coil output, 544 cold water, 1067 commercial dimensions, 606 conduits for, 643 connection to heating units, 508, 520 corrosion, 955, 958 covering, 626, 628 design, hot water system, 530 dimensions, 606 economical thickness insula tion, 637 expansion, 610 fittings, 613, 627 fitting equivalent, 497, 525, 1073, 1074 flexibility, 611 forced circulation, 530 friction loss, 525 hangers, 612 heat losses, 625 hot water heating systems, 530 hot water supply, 1084 inside dimensions, 606 insulation, 625 insulation prevent freezing, 635 low temperature insulation, 634 materials, 605, 960 - one-pipe forced circulation, 533 . one-pipe gravity circulation, 499 one-pipe vapor, 503 overhead distribution, 487, 645,1085 properties, 607 sizes, 491, 495 gas. 378 high pressure steam. 499 hot water forced circulation, 533,536 hot water gravity circula tion, 533, 534 indirect heating units, 506 low pressure, 497 maximum velocity, 495, 530 one pipe riser, 498,504 one pipe vapor, 5u3 XIX Pipe, piping {continued) orifice systems, 492 pressure drop, 494,. sub-atmospheric systems, 505 tables for steam, 496^503 two-pipe forced cireulation, 535 . two-pipe gravity circula tion, 534 two-pipe low pressure, 504 two-pipe riser, 498 two-pipe vapor systems, 504 vacuum systems, 505 water supply systems, 1074, 1076 steam distribution, 491, 641 steam beating systems, 495 supports, 612 surface, 607, 627 symbols for drawings, 17 tax, 390-392 threading practice, 613, 614 thread connections, 613 threads, 613 tunnels, 645 underground insulation, 642 unit heater connections, 482, 522, 581 water supply 1067 welding, 616 Pitot tubes, 84,1105 Plate cell, 917 Plenum absorbers, 919 Plenum chamber, 6 Pneumatic control systems, 871 Pollution of air, 151 Polyphase motors. 893 Ponds, 781 Potentiometer, 7,1101 Power, 7 Precipitators, 757, 763 Pre-cooling, 662 _ Premature infant nurseries, 140 Pressure absolute, 7 atmospheric, 1 changes in ducts, 699 gages, 1103 loss, elbows, 497, 525, 706, 1074 loss, water supply piping, 1070-1076 measurement, 1103 harometer, 1104 regulators, 506, 644, 872 static, 7 taps, 83 total, 7 vapor, 7 velocity, 7 Prime surface (see Heating Sw- face), 9 Propeller fan, 734, 750 Protective coatings, 962 Psychrometer, 7.1111 Psychrometric chart, 51,124 Pump, pumps condensate return, 510 TTwhftnifgd circulators, 534 vacuum heating, 510 - controls, 511 . piston displacement, 511 Pyrometer, 7,1102 optical, 1102 radiation, 1102 R Radial flow fan. 733 Radiant drying, 1042 Radiant heating, (see Panel Heating) . Radiation, 7, 89 baseboard, 541, 544, 547 equation, 92 load, 393 shape factor, 95, 557 Heating Ventilating Air Conditioning Guide 1954 Radiator, radiators, 7, 541 .baseboard, 541, 544, 547 codes, 546, 1124 concealed, 545, 551 connections, 519 correction factor, 548 . direct, 7 ' effect oi paint, 548 enclosed, 551 gas-fired, 377 beat emission of, 541 heating, 550 heating effect, 548 output of, 541, 546 panel, 6 ratings, 546, 548 recessed, 7, 545. tube, 542 types of,. 542 warm air, 377 Railway air conditioning, 1051 air cleaning, 1052 air distribution, 1052 heating, 1051 humidity control, 1054 . refrigeration, 1052 summer systems, 1052 temperature control, 1054 ventilation, 1053 winter systems, 1051 Reciprocating compressors, 845 Recording equipment, 873 Rectangular duct equivalents, 702 Reducing valves, 506, 644 Reflective insulation, 170,180 Refrigerant, refrigerants, 8, 825 dichlorodifluoromethane, 825, 826 feeds, 803, 804 monochlorodifluoromethane, 828,829 monofluorotrichloromethane, 830 pipe size, 853 water, 838, 841 Refrigeration, 823, 1052, 1056 1063 absorption system, 839 accessories, 856 air cycle. 836 basic concepts, 823 complex cycles, 836 compressors, 845-848 condensers (see Condensers), 848 control, 850 coolers, 849 definitions, 823 discharge pressure, 834 equipment selection, 845, 857 evaporators, 849 expansion valves, 851 float valves, 851 heat pump, 842, 843 ice systems, 841 load, 265 mechanical, 823, 831, 1052, 1056, 1063 piping, 853 reverse cycle, 824, 843 ship, 1063 simple cycle, 830 Bteam jet, 837 subcooling, 834 suction, 833 superheating, 834 symbols for drawing, 17 theory, 823 - ton of, 8, 823 types of compressors (see Compressors), 845 vapor compression cycle, 830 water jacket, 834 Regain, 988 control of, 988 hygroscopic materials, 990 static, 718 Register, registers, (see Grilles), 451, 453, 462, 684, 685, 692 ' air supply noises, 919 mechanical furnace systems, 462 noises, 919 selection, 451, 462, 686 Reheat, 654, 663 Relative humidity, 5, 25, 52, 1111 measurement of, 1111 Relief valve, 540 Repulsion induction motors, 892, 897 Residence control systems, 875 air conditioning, 877, 1091 domestic hot water supply, 1067 heating, 875 cooling methods, 479 gravity furnace systems, 451 heat loss problems, 259 hot water heating system, 523 mechanical furnace system, 461 steam heating system, 481 Residential Air Condition ing. 1091 Resistance thermometers, 1102 Resistors, 927 Return grille, 453,922 mains, 8, 481, 500, 503, 525-628 openings, 453, 692 ' Reverse cycle refrigeration, 824 , 843 Reversed return system, 8, 530 Ringelmann chart, 1116 Roof, roofs heat flow through, 173, 193 188,278-284 time lag of solar radiation, 300 ventilators, 230 Room air conditioners, 1093 air motion, 668, 683 control, 876 coolers, 591, 597, 601 cross transmission noise, 922 latent heat, 302 . noise level, 909 operating, 138 sensible heat, 302 Rotary dryer, 1044 Rotary oil burner, 366 Run-around system, 662 "s Sanitary ventilation, 132 Saturated air, 1, 25, 29 . Saturation, 8 degree of, 8,29 pressure, 7 Scale. 945 cause and prevention, 945, 949 . closed systems, 951 heating systems, 952 high temperature, 952 open systems, 652, 955 Secondary air, 328, 345, 378 Sectional boiler, 386 Sensible cooling, 662 Sensible heat, 263, 274, 304, 306 gain, 263, 297-307, 666 1068,254 Sheet metal gages, 724, 725 XX Ship heating, ventilation, air conditioning. 1060 air conditioning, 1060 design conditions. 1061 factors affecting (resign, 1060 general consideration, 1060 - heating, 1061 insulation of hull,. 1060 . ducts. 1061 refrigeration, 1063 requirements for space, 1063 bakery, 1062 bath, 1062 cargo, 1063 food handling, 1062 elley, 1062 undry, 1062 living, 1062 machinery, 1061 shower, 1062 storeroom, 1063 toilets, 1062 washroom, 1062 systems, typical, 1064 ventilating, 1061 Silica gel, 863 Silicon dioxide, 863 Single phase motors, 896 Slime, 947, 953 cause and prevention, 945, 947,953 . formers, 947 Slotted outlets, 685 Sludge, 945, cause and prevention, 949 Smoke, 8, 154, 326 abatement, 154, 326 density measurements, 1115 Smokeless arch, 8 Smokeless combustion, 326 Snow melting, 565 circulating medium, 570 design, 566 draining, 571 drifting snow, 571 heat from slab, 569 heating requirements, 566 installation, 570 internal corrosion, 571 pumping head, 567 safety, 570 slab construction, 571 snowfall, 568 Soil specific heat, 176 Solar constant, 8, 274 Solar heat, 274 absorbed by glass, 287 altitude, 275 calculation tables, 275-277, 291-296 through shaded windows, 298,299 time lag, 300 transmission of, 274 through glass, 287 through roofs, 278, 280 through walls, 278, 282 Solar heat gain, 274 basic principles, 274 design for figured rolled glass, 295 design for flat glass, 289 - ` design for glass block, 297 deviation from design, 297 shading glass, 298 Solar radiation, 274 absorption of, 274 magnitude, 274 Solar water heater, 1087 Sol-Air temperature, 279 Soot, 151, 326, 354 Sorbente, 861 absorbents, 861, 866 adsorbents, 861 , Index to Technical Data Section Sound (see Noise), 905 absorbers, 914, 917 apparatus for measuring, 906 attenuation, 608, 913 control, 905,923 cross transmission between rooms, 922 - . general problem 906 duct absorbers, 914, 616, 917 intensity, 905 isolation, 595 levels, 906, 910 measurement, 906 outlet absorbere, 919 pressure, 905 unit, 905 - Space heaters, 406, 433 design, 407 , rating, 406 Split systems, 8 Splitter dampers, 691 Spray apparatus, 773 booths, 1009 cooling, 779 cooling ponds, 761 cooling towers, 783 dehumidifier, 657, 777 distribution, 776 dryer, 1045, 1046 equipment, 773 generation, 779 umidifiers, 775, 777, 779, 780 unit air conditioner, 595 Spread, air distribution, 668, 671 . Square foot of heating surface, 8 Squirrel-cage induction motor. 895, 899, 900, Stack, stacks, 217, 231, 411, 451 height, 8, 233 wall, 451, 454 smoke, 411 Standard, standards, 1119 air distribution, 668 atmosphere, 63 Standard air, 1 Static . electricity elimination, 992 pressure, 7, 711, 734, 735 regain, 718 Steady flow, energy equation. Steam, 8 coils, 801, 808 . distribution piping, 491, 641 estimating consumption, 445, flow, 493, 494 flow measurement, 78 , 647 heated equipment, 307 heating systems, 481 . condensate return, 481 connections to units, 520 control valves, 521 corrosion, 952 drips, 517 flash leg, 518 gravity one-pipe air-vent. 482 gravity return, 481 Hartford return, 483 high pressure steam, 485 low pressure steam, 485 mechanical return, 481' one-pipe, 482 orifice, 490 piping for, 491 sub-atmospheric, 489 two pipe, 484 vacuum, 488 vapor, 486 jet type system, 837 meters, 78, 647 panel heating, 553 pipe capacities, 494-503 properties, 32,49 rates, 649 Steam (continued) reducing valves, 506 requirements, 445, 649 runout 483 superheated, 8 tables, 32, 49 traps, 512 valves, 5zl velocity, 495 Steel boilers, 386 Sterilization of air, 132 Stoker, stokers, 357 classification of, 357 - combustion adjustments, 362 combustion process, 359 controls, 365 furnace design, 363 mechanical, 357 overfeed flat grate, 361 overfeed inclined grate, 359 sizing and ratings, 364 underfeed, 360 Sub-atmospheric systems, 489 Summer air conditioning sys tem, 265, 479, 653 Summer comfort, 127, 128 Superheated steam, 8 Supply mftinq , 8 Supply openings, 462, 667, 684, 685, 686, 919, 1053 measurement of velocities. 1109 Supports, pipe, 612 Surface condensation, 202, 635 conductance, 3,170,179 coefficients, 92, 170,632 external pipe, 627 heating, 9 extended, 9 temp1e10ra2 ture, 199, 405. 561 * Suspended unit heater^ 576 Symbols, 12,13,14 air conditioning, 21 . for drawings, 17 heating, 18 piping, 17 ventilating, 19 T Tables air changes, 223 air conditioning temperatures and humidities, 978-988 air duct size, 454 . air leakage, 218, 220, 221 air requirements, 113 air, volume of, 32 allowable concentration gases, vapors, 158 dust, fumes, 160,161 altitude, pressure and tem perature , 63 aluminum, 713 analytical solutions for heat conduction, 107 anthracite size, 323 anti-freeze solutions, 570 atmospheric gas, 949 atmospheric impurities, 154. 949 attenuation between grille and room, 915 data, lining board, 917 in straight ducts, 913 of branches, 914 of elbows. 914 of plate absorber, 918 attic ventilation, 214 azimuth angle, 277- black body radiation, 96 boiler ratings, 388, 389, 391 bonnet pressure, 477 building load factors, 450 calorific value, 322, 334, 338, 346 capacity constants, unit heat* ere, 579 . XXI Tables (continued) . capture velocities, 1004 carbon dioxide maximum, 352 cast-iron boiler rating, 392 ceiling temperature, 249 chimney draft, 425 chimney efficiency, 422 circular equivalents of - rec tangular ducts, 703 classification of coals, 323 . hot water heating systems. 530 motors, 892 water, 946 - climatic conditions, 241, 269 coal analyses, 322 coal classification, 323 codes, 1119 coil capacity balance, 811 coil heat emission, 544 combustible elements and compounds, 346 combustion rates, 394 comfort ranges, 123 condenser design data, 798 conductance, 93, 170-175, 178 180 air space, 170,180 conduction problem solution. 101,107 conductivity materials 91 171-176, 180 ' contaminant exhaust, 1004 convection conductances, 93 conversion equations, 15 conveying velocity, 1006-1009 cooling coil arrangements. 810 * cooling tower performance. 896 cooling tower pipe size, 1076 copper elbow equivalents, 525 copper sheets, 726 copper tube capacity. 528 copper tube dimensions, 668 copper tube surface, 627 correction factors steam radiatin', 548 water radiator, 548 unit heaters, 579 corrosion resistance, 1018 cost of air conditioning, 968 decibel scale, 607 degree-dayB for cities. 439. 448 ' design dry- and wet-bulb temperatures, 241, 248, 266. 269, 277, 978, 1081 design humidity, 978-988 dew-point, fuels, 355 .' draft in chimneys, 425 draft requirements of appli ances, 426 duct attenuation, 913. duct combinations, 465, 466 duct pages, 724 duct joints, 724 duct pressure drop, 478 duct sizing, 454, 455, 465, 466. 473, 474, 1018 duct velocity, 714 duct weight, 725, 726 dust concentration, 155 elbow attenuation, 914 elbow equivalent, 525, 1074 electric water heaters, 939 electric heating systems, 930 emissivity factors, 5 end reflection. 918 environmental conditions, limits, 118 equivalent length of fittings, 454. 456, 458, 497,' 1075 equivalent temperature, dif ferentials, 280,282 exhaust pipes for machines. 1006-1009. exhaust velocities, 1004, 1006 1009 . expansion tank sizes, 538 fabric filters, 768 Heating Ventilating , Air Conditioning Guide 1954 Tables (omdinued) fan outlet velocity, 746 fan speed, 746 _ fitting allowance, 445, 470, 497 fitting dimensions, 616-622 fixture flow, 1068 fixture unite, 1068 flammability of gases and vapois, 162 flanged fittings surfare, 627 flue gas dewpoint. 355 free convection, 94 friction loes, pipe, 378, 494, 498, 503, 526, 528, 1074 friction valves and fittings, 456, 497, fuel combustion, 348 fuel consumption, 444, 445 fuel oil properties, 332 fumes, concentration, 160 gas analysis, 338 gas piping capacity, 379 gaseous fuel properties, 338 glass absorptance, 288 glass transmittance, 288 graphical symbols, 17 heat absorbed, cooling water, 791 ,,,, heat conductance, 93,101, 170 175 heat consumption record, 447 heat equivalents, 259 beat flow walls and roofs, 187-197, 280-284 heat gain appliances, 306 cod heat emission, 544 glass, 291-293 ^ glass blocks, 294--296 insulated cold pipes, 636 heat loss . bare copper pipe, 626 bare steel pipe, 544, 626 basement, 252 ' floor, 254 pipe coils, 544 radiation, 96 residence, 261, 262 ' room, 563 heat pump, 842 . heat transmission coefficients. 187 . building construction, 187 197, 284 doors, 197 glass, 197 roofs, 193-197, 284 walls, 187 water heaters, 1084 hot water demand, 1077, 1078, hot water pipe sixes, 526 628, 1070-1072 . humidities, industrial air conditioning, 978-988 hygroscopic materials, 990 incident angle, 276 inertial separator, 766 infiltration through outside doors, 222 ' infiltration through walls, 218 infiltration through windows, 220 inflammability, gases, 162 inside temperatures, 248, 266 inside temperatures, 247, 269, 978, 1061 . instantaneous solar heat gain, 291-296 insulation conductivity, 628 insulation factors, 628 jpcmlfttinn thickness, 636, 637 insulation to prevent freezing, 637 insulation, underground, 639 intake velocity, 692 iron elbow equivalents, 525 life of equipment, 970 limits for contaminants, 1.M load factors, 450 maintenance cost, 972 Tables (continued) maximum allowable, concen trations dust, fumes, mists, 160 dusts, 160,161 flammable gases, 158 - .gases, 158 ' vapors, 158 metal gages for ducts, 724, 1015 meter performance,.1074 _ minimum outdoor air require ments to remove odors, 113 moisture content for mate rials, 990 _ moisture regain, 990 moisture transfer, 208 motor classification, 892 motor current, 893 motor design limits, 890 motor drive applications, 896 motor horsepower, 890 motor ratings, 898 motor speed range, 890 motor voltage, 890 noise levels, 909 , oil fuel specifications, 332 oil heat value, 334 operating conditions, 858 operating cost, 968, 971,972 operating hours, 973 orifice capacities, 492, 529 outdoor air requirement, 113 outlet velocities, 746 outside temperature, 241, 269, 442 . owning and operating cost, 971 particle sixe, 153, 154 particulate matter, size, 153 permeability to vapor, 208 physiological response to heat, 117 ' pipe capacity, 379, 494, 498, 500-504, 526, 528, 1076 pipe covering factors, 628 pipe dimensions, 606-609 pipe expansion, 610 pipe fitting dimensions, 616-- 621 . pipe freezing prevention, 637 pipe insulation, 637 _ pipeARrefl ctangular equivalents, pipe roughness, 73 pipe surface, 627 pipe volume, 539 ducts, 478 elbows, 525 fittingB, 497, 525 refrigerant line, 854 , 855 registers, 475, 476 return intake, 692 properties of air. 32, 346 d icnlorodifluoromethane, 827 fuel oil, 332 gaseous fuels, 338 moist air, 32 monochlorodifluoro- meth&ne, 829 monofluorotnchloro- methane, 830 steam, 49 water, 40 radiation, black body, 96 radiation factors, 95 radiation problem solution, 97 radiator heat loss correction factors, 546 radiator sixes, 542, 543, radiator water content, 539 rating air conditioning units, rating steel boilers, 388 ratio of specific heats, 73 refrigerant properties, 827, 829 , 830 refrigerant . capacity, 854, 855, 858 Tables (continued) refrigeration equipment selec tion, 858 regain of hygroscopic mate rials, 990 requirements for fuel oil, 332 return pipe capacities, 500,503 room temperature differential, 249 screen mesh, 154 aHaving effect, 299 sheet metal gages for ducts, 724, 1015 . . ship design conditions, 1061 slime control, 955 - slime formers, 947 smoke chart numbers, 1116 snowfall data, 568 snow melting systems, 569 sodium dichromate, 958 soil conductivity, 176 sol-air temperature, 279 solar altitude, 275, 277 solar azimuth, 277 solar declination, 278 solar heater design, 1089 solar heat gain, 280, 282--283, 291 . solar radiation, 275 sound attenuation, 913-915, 917,918 . sound level, 909, 910 # sound pressures and in tensities, 907 specific gravity factors, 379 specific heat of compressible fluids, 73 specific heat ratio, 73 _ . spray pond design data, 783 steady-state conduction prob lems, 101 steam consumption of build ings, 446 steam conversion factors, 548 steam pipe capacities, 494, 496-503 steam table, 49 steel boiler ratings, 388, 389 summer climatic conditions, 269 . . summer design conditions, 266,269 surface conductance, 93, 170 temperature differential, 249, 280,282 .. temperature, industrial air conditioning, 978-988 temperature, inside, 248, 266, 978-988 . temperature limit for men, 118 temperature range, 268 temperature, summer, 269 temperature, winter, 241 thrTn.l conduction problems, 107, 113 thermal conductivity, 91, 628 thermal convection conduct ance, 93 a . thermodynamic properties moist air, 32 water, 40 transmittance, glass, 288, 291 unit conditioner rating, 599 unit fuel consumption, 444, 445 unit heater capacity factors, 579 .. unit ventilator capacities, 587 upper temperature limits, 118 vanes in elbows, 709 vapor transfer, 207 velocity, return intake, 692 ventilation standards, 273 warm air ducts, 454, 455, 458 warm air fittings, 456 warming-up allowance, 393 water analyses, 946, 947, 948, 965 . water cooling effectiveness, 791 water fixture flow, 1068 water TPn'n temperatures, 776 Index to Technical Data Section Tables (Continued) water meter performance, 1074 water pipe capacities, 526, 528 water requirements, 1077,1078, 1080 weight of air, 32' weights of ducts, 725-726 ` wet collectors, 767 winter clim&tic conditions, 241 winter design temperatures, 241 . Tank, tanks expansion, 536-540 Tax, pipe, 393 Temperature, temperatures absolute, 9, 30 attic, 250 automatic control, 871, 874 basement, 253 .. control for railway passenger car, 1054 control service water, 1085 design wet-bulb, 789 dew-point, 26 dry-bulb, 9 drying, 960, 1038 effective, 9 ground, 252, 253 hazard, 117 industrial, 977 inside, 248, 266, 1061 ceilings, high, 248 proper level, 248 mean radiant, 120, 560 measurement, 1099 - pyrometers, 1102 thermocouple, 1100 thermometers, 1099 outside, 241, 269 surface, 405, 1102 . thermodynamic wet-bulb, 26 unheated spaces, 252 water main, 776 wet-bulb, 9 Terminology, 1 '. Test methods, 1099, 1119 Testing codes, 1119 Therapy cold, 143 fever, 142 oxygen, 145 Thermal conductance, 167, 170, 181 conduction equation, 90 conductivity, 90, 168 oonvection, 89, 91 convection equation, 91 expansion of pipe, 610 integrator, 1114 interchanges of body, 113 radiation equation, 92 resistance, 8, 167, 170, 180 resistivity, 8,170 steady-state conduction prob lems, 101 transmittance, 255 unit conductances for convec tion, 93 Thermocouples, 1100 Thermodynamics, 23 air and water mixture, 25, 29, 32 laws. of. 9, 23 wet-bulb temperature, 26 Thermometers, 1099 alcohol, 1099 dry-bulb, 1099 globe, 549, 1114 Kata, 549, 1110 mercurial, 1099 resistance. 1102 stem correction, 1099 wet-bulb, 1111 Thermostat, 9, 872 room. 876 Time lag through walls and roofs, 300, 657 Ton of refrigeration, 8 Total heat, 5 Total pressure, 7 Tower, towers, 780 cooling, design, 790 cooling, performance, 792 mechanical draft, 785 - natural draft, 783 selection, 795 spray cooling, 783 - Transmission heat losses, 252-256 solar heat, 284, 287 Transmittance, thermal, 9 Transportation air conditioning, 1051 temperature and humidity control, 1054, 1055, 1057, 1064 Trap, traps, 512 alternating receiver, 516 automatic return, 487, 516 bucket, 514 float, 512 impulse, 515 installation, 516 steam, 512 thermostatic, 513 tilting, 515 . Traveling-grate stoker, 359, 361 Treatment of disease, 131,137 Tropical air cooling, 136 Tube radiator, 7 Tunnel dryer, 1044 Tunnels, pipe, 645 Turning vane, 673, 677, 695, 697 Two-pipe system, 10, 484, 528 u Ultra-violet light. 113,132,156 Underfeed stoker, 358 Underground pipe insulation, 639 ^ Unheated space temperatures, 252 Unit, units air cleaners, 751, 764 air conditioners, 591 application, 598 cooling, 601 dehumidifying, 596 humidifying, 595 ratings, 599 remote units, 596 sound isolation, 595 types of, 591 air coolers, 591, 601 defrosting, 602 design. 601 performance, 601 ratings, 602 types of, 591 air filters, 751 British thermal, 2 dehumidification, 596 direct-indirect heating, 3 fuel consumption, 433 heaters, 575 application, 577 automatic control, 580 boiler capacity, 584 capacity factors, 579, 584 classification, 575 control, 580, 878 direct-fired, 368, 575 electric, 578 maintenance, 583 outlet velocity, 577 piping connections, 581 ratings, 578 temperatures, 561, 562, 580 types of, 575 xxiii Unit, Units (continued) humidifiers, 780 types, of, 780 induction, 660, 661 noise measurement, 905 systems, 575 ventilators, 584 air exhaust vents, 589 applications, 587 capacity, 587 control, 588, 855 location, 58S ratings, 585 selection, 588 window, 589 Unitary equipment, 575 definitions, 575 V Vacuum ' cooling units, 837 heating pumps, 510 control, 511 piston displacement, 511 heating system, 10, 481 down-feed, 486, 488 unit-heater connection, 581 Valve, valves. 520, 521, 601, 621 automatic, 623 check, 623 control, 521 expansion, 851 gate, 622 globe, 622 reducing pressure, 506 relief, 540 Vane, vanes, 668, 681, 682, 709 Vaned outlets, 681, 682 Vapor, vapors, 151 adsorption, 769 barrier, 211 heating systems, 10, 486 unit beater connection, 581 pressure, 7 transmission, 204 Vaporizing oii burner, 367 Velocity, 10 capture, 982 coil, 595, 601, 808, 809 conveying, 1006, 1014 duct, 714, 1006 exhaust intakes, 692, 1004 1006-1010 hood, 1004 operating, 714, 746, 1004, 1006 1010 pressure, 7 reduction method, 715 return grilles, 692 unit heater, 575, 576 Ventilation. 10, 268 animal shelters, 232-236 dairy stables, 233 garages, 236 living space, 213 natural, 225 general rules, 231 passenger bus in summer, 1056 railway passenger car, 1051 rules, 231 ship. 1061 . symbols for drawings, 17 systems, 653 wails and attics,.213 wind forces, 226 Ventilator, ventilators, 230 control, 231 roof, 230 unit, 584, 879 control, 879 window. 589 Vertical blow unit heater, 576 Vertical openings, 224 sealing of, 224 Heating Ventilating , Air Conditioning Guide 1954 Vibration, machine, 923 Viscous filters, 753 impingement, 752 Vitiation of air, 111 Voltune . control, 691 furnace, 364, 371 specific, 10 w rail, WUU3 beat flow through, 187-190,278 beat transfer coefficients, 89, 187-190 , infiltration through. 218 time lag of solar radiation, 300 Warm air gravity heating system, 451 combination carrying ca pacity, 457, 458 design procedure, 453, 457, 459 extended plenum, 459 furnace capacity401 installation practice, 451,452 standardized combinations, 454 mechanical heating systems, 461 air distribution, 461 automatic control, 405,467 celling panel system, 477 combination of parts, 464 cooling methods, 479,1093 continuous circulation, 472 dampers, 463 ' design procedure, 464, 465 ducts, 463 fans, 400 filters, 400 furnace, 399 heavy duty, 400 selection, 467 humidification, 405 large systems, 465 perimeter system, 477 pressure drop, 478 registers ana grills, 462 standard combinations, 454, 464 panel heating, 477 radiators, 377 Washer, washers, 773 air, 1, 773 cooling, 777 _ dehumidification, 777 humidification, 775 Water. _ analysis, 945 _ . atmospheric cooling equip ment, 773, 783 characteristics, 946 classification, 946 ' coils, 802, 1080 content of radiators, 539 . control temperature service, 1085 cooled condenser, 848 cooling tower, 780 corrosion treatment, 945 demand, 1069 faucets, 1068, 1073 fittings, lo6S, 1073, 1074 fixtures, 1068 fixture units, 1068 formed deposits, 945 coal-fired, 1080 solar, 1087 heating, 938-1080 load, 1077 776 meters, 1073, 1074 mineralized, 946 properties of, 40 services, 1067 _ storage capacity. 1077 supply piping, 1066,1067,1076, arrangement, 1085 temperature control, 1085 thermodynamic properties of, treating chemicals, 952, 955, 956, 957, 958, 959 well temperatures, 778 Water vapor, 25, 32-40, 201 condensation in buildings, 201 saturation pressure, 25, 40 specific enthalpy, 4 specific volume, 10, 40 surface condensation, 202 Welding, 605, 616 Wet-bulb temperature (see 'Temperature), 9, 26, 789 Wet return, 8, 481 Wind, winds forces, 218, 225 due to stack effect, 218 natural draft equipment, 783 selection of, velocity, 240, 241, Window, windows coefficients of transmission, 197 leakage, 219 solar radiation through, 287 ventUators, 589 Winter air conditioning system, 653 comfort zone, 124 freezing equipment, 798 Wound rotor motor, 894 Wrought-iron pipe, 605 Wrought-steel pipe, 605 Y Year-round air conditioning system, 653, 1091 air flow in, 653, 1096 control methods, 654 design procedure, 666 equipment arrangement, 654 656 installation, 654 location of apparatus, 665, 1095 selection, 663 Z Zone control, 654 Zone of evaporative regulation, 115 Zoning, 540, 654 control, 654, 886 reheat, 654 volume control, 655 XXIV CHAPTER 1 Glossary of Physical and Heating, Ventilating, Refrigerating and Air Conditioning Terms Used in the Text Absolute Zero: The zero from which absolute temperature is reckoned. Ap proximately -- 273.2 C or --459.8 F. . Absorbent: A sorbent which changes physically or chemically, 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.t 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), a = Acceleration Due 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 ine 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 undergoing 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 ex tracting one. or more substances present in an atmosphere or mixture of gases and liquids, unaccompanied by physical or chemical change. Commercial adsorbent materials 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.t dust, fog, smoke. Air Cleaner: A device designed for the purpose of removing airborne impurities such as dusts, gases, vapors, fumes and smokes. (Air cleaners include air washers, air filters, electrostatic precipitators and charcoal filters.) Air Conditioning: The simultaneous control of allKor at least the first three, of those factors affecting both the physical and chemical conditions of the atmosphere within any structure. These factors include temperature, humidity, motion, distri bution, dust, bacteria, odors and toxic gases, most of which affect in greater or lesser degree human health or comfort. (See Comfort Air Conditioning ) 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 U.075 lb per cu ft and an absolute viscosity of 1.22 X Iff"6 lb mass per (ft) (sec). This is substantially equivalent to dry air at 70 F and 29.92 in. (Hg) barometer. Air Washer: An enclosure in which air is drawn or forced through a spray of water in order to cleanse, humidify, or dehumidify 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 due to the weight of the atmosphere. It is the pressure indicated by a barometer. Standard Atmospheric Pressure or Standard Atmosphere is the pressure of 76 cm of mercury having a density of 13.5951 grams per cu cm, under standard gravity of 980.665 cm per (sec) (sec). It is equivalent to 14.696.lb psi or 29.921 in. of mercury at 32 F. *- Baffle: A surface used for deflecting fluids, usually in the form of a plate or wall. 1 CHAPTER 1 1954 Guide Blast Heater: A set of heat 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 per ceptible rise due to temperature difference and loss of velocity. . Boiler Heating Surface: 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, in which the fluid being heated forms part of the circulating system; this surface shall be measured on the side receiving heat. This includes the boiler, water walls, water screens, and water floor. (ASME Power Test Codes, Series 1929.),. . . Direct Heating Surface is generally understood to be the boiler heating surface subject to direct radiation from the surface of the grate, or from the surfaces of oil or gas burners. ' Indirect Heating Surface is the boiler healing 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 output of 970.3 X 34.5 = 33,475 Btu per hr. British Thermal Unit: Classically, the Btu is defined as the quantity of heat required to raise the temperature of 1 lb of water 1 Fahrenheit degree. By this definition the exact value depends upon the initial temperature of the water. Several values of the Btu are in more or less common use, each differing from the others by a slight amount. One of the more common of these is the mean Btu which is defined as 1/180 of the heat required to raise the temperature of 1 lb of water from 32 F to 212 F at a constant atmospheric pressure of 14.696 lb per sq in. absolute. For most accurate work the International Table (I.T.) Btu is usually used. This is defined by the relation: 1 (I.T.) Btu per (pound) (Fahrenheit degree) = 1 (I.T.) calorie per (gram) (Centigrade degree). This value corresponds to the amount of heat required to raise the temperature of 1 lb of water 1 Fahrenheit degree at 58 F and also at 149 F. The mean Btu corresponds to 1.0008 (I.T.) Btu. By-Pass: A pipe or duct, usually controlled by valve or damper, for conveying a fluid around an element of a system. . Calorie (Gram Calorie): Classically the calorie is defined as the quantity of heat required to raise the temperature of 1 gram of water 1 Centigrade degree. By this definition the exact value depends upon the initial temperature of the water. Several values of the calorie are in more or less common use, each differing from the others by a slight amount. Among these are the 15 C calorie and the 17\ C calorie. The mean calorie, i.e., 1/100 the quantity of heat required to raise the temperature of 1 gran, of water from 0 C to 100 C, is also extensively used. For the most accurate work the International Table (I.T.) calorie, defined in terms of the international electrical units, is usually used: 1 (I.T.) calorie = 1/860 inter national watt-hour = 3,600/860 international watt-seconds or international joules. The kilocalorie -- 1,000 cal. Central Fan System: A mechanical indirect system of heating, 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 30.) 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 unheated outside air due to the difference in density of outside and inside air. Comfort Air Conditioning: The process by which simultaneously the temperature, moisture content, movement and quality of the air in enclosed spaces intended for human occupancy may be maintained within required limits. (See Air Condi tioning.) Comfort Line: A line on the comfort chart showing relation between the effective temperature and the percentage of adults feeling comfortable. Comfort Zone {Average): The range of effective temperatures over which the ma jority (50 percent or more) of adults feelcomfortable. (See Chapter 6.) Condensate: The liquid formed by condensation of a vapor. In steam heating, water condensed'from steam; in air conditioning, water extracted from air, as by con densation on the cooling coil of a refrigeration machine. Condensation: The process of changing a vapor into liquid by the extraction of Tferminology 3 heat. Condensation of steam or water vapor, is effected in eithersteam condensers or in dehumidifying coils and the resulting water is called condensate. . . Conductance, Surface (Unit): The amount of heat transferred by radiation, con duction, and convection from unit; area of. a surface to the air or other fluid in contact with it, or vice versa, in unit time fora unit difference .in temperature between the surface and the. fluid. The common unit is: Btu per, (hour) (square foot) (Fahren heit degree). 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 temperature of the surface. . .. .. ........... .. ./ Conductance, Thermal:. The .time rate of heat flow through, unit area of a body, of given size and shape, per unit temperature differenced Common unit is: Btu per (hour) (square foot) (Fahrenheit degree). Symbol C. . Conduction, Thermal: The process of heat transfer.thrpugh 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 homo-: geneous substance under the influence of a unit temperature gradient. Common uiiits are: Btu'per (hour) (square foot) (Fahrenh`eit'!degree per inch). Symbol k. ducCtoionnd.uctor, Thermal: A m.a.ter.ial which read. il.y...transmits heat by means of con . Convection: The motion resulting in a fluid from the differences in density.and the action of gravity. In heat transmission 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 removed mechanically, or by gravity (Gravity Convector): .. Such a surface may or may not be enclosed or concealed. When concealed and enclosed the resulting device is sometimes referred to as a concealed radiator. (See also definition of .Radiator.) (See also Chapter 23.) ' '' :........ *. \ " . Decibel > A unit used to express the.relation.between two,amounts of power. By definition the difference in decibels between two powers Pi and Pj, Pjbeing, the larger, is: db difference = 10 logioP2/Pi/ In acoustics the threshold of hearing at 1,000 cycles per sec has been standardized aI 10"l# watts per sq cm. If P* is the power in watts per square centimeter of a measured sound, then 10 logio Pj/10-16 is the db difference above'the`threshold and is known as the intensity level. This is a definite recognized way of describing the intensity of a sound. : - Declination of Sun: The angle above or below equatorial plane: . It is'plus if north of the plane, and minus if Ibelow. Celestral objects are located by declination. Degree-Day: A unit; based upon temperature difference and time, used in estimat ing 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 exists.as many degree-days as there are Fahrenheit degrees difference in temperature between the mean temperature for the day and 65 F. ... . .. . Dehumidify: 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, hygro scopic water, and water of crystallization1 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. . ' ' 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. - ; 1' - '. 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 (Sfeamj: A pipe which carries steam downward to the heating units and into which the condensate from the heating units drains. 4 CHAPTER 1 ' 1954 Guide - Down-Feed Sys tern (Steam): A steam-heating- system in which the supply mains are above the level of the heating units which they serve. Draft: A current of air. Usually refers to the pressure difference 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 between 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 con densation from the 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. The 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 8.) Enthalpy: A term used in lieu of total heat or heat content. Expressible in Btu per pound. Mathematically defined as h = u + pvfJ. When a change occurs at con stant pressure, as when water is boiled, the change in enthalpy is equal to the heat added, in this case latent heat. 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 avail able energy can occur spontaneously. Enthalpy, Specific: A term sometimes applied to enthalpy per unit weight, the English unit being Btu per pound. . : Entropy: The 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 -- JdQ/T. . .. . These formulas are applicable when temperature is not constant. During a re versible adiabatic change, entropy is constant. During a reversible isothermal change, the heat absorbed by the substance is equal to the product of the absolute 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 degree, 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 corresponding atmospheric pressure. ; Fan Furnace System: See Warm Air Heating System. . . Fog: Suspended liquid droplets generated by condensation from the gaseous to.the liquid state, or by breaking up a liquid into a dispersed state, such as by splashing, foaming, and atomizing. (See also Chapter 8.) . Force: The action on a body which tends to change its relative 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 inclusive 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 volatilization from molten metals, etc., and often accompanied by a chemical reaction such as oxidation. Fumes flocculate and sometimes coalesce. (See also Chapter 8.) ..... . . . Furnace: That part of a boiler or warm air heating plant in which combustion takes place. Also a complete heating unit for transferring heat from fuel being burned to the air supplied to a heating system. . Furnace Volume (Total): 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 horizontal-return tubular boiler settings, unless manifestly ineffective (t.e., no gas 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 being used. For Scotch or other internally-fired boilers, Terminology 5 it is the cubical contents of the furnace, flues and combustion chamber, up to the plane of first entry into the tubes. (ASME 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 meas ured in the plane of the top surface of the grate, except that with special furnaces, 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 in double grate down-draft boilers, the effective area shall, tie taken as the area of the upper grate plus one-eighth of the area of the lower grate, both areas being estimated as previously 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: The formof energy that is transferred by virtue of a temperature difference. At constant pressure heat added is equal to enthalpy change. Heat, Humid: Ratio of increase of enthalpy per pound of dry air to rise of tem perature 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 indicate any portion of heat which changes only the temperature 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, 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) (Fahrenheit degree), calories per (gram) (Centigrade degree). For gases, both specific heat at constant pressure (cp) and specific heat at constant volume (cv) are frequently used. In air conditioning, cp is usually used. 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 materials and structures. (See thermal conductance, thermal conductivity, thermal resistance, thermal resistivity, thermal transmittance, etc.) Heating Element, Electric: A unit assembly consisting of a resistor, insulated sup ports, 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 insulation, 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 me dium 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. Humidistat: 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 per 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 saturated 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. Also called Specific Humidity. Humidity, Specific: See Humidity Ratio. Hygrostat: Same as Humidistat. . 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 6 CHAPTER 1 1954 Guide sometimes taken as.0 C.andfsometimes as 62 F. One inch .of water at 62 F = 5.197 lb per sq ft. : ..v. ' t .. . ., Insulation {Thermal) ', A materialhaving 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 : Ad 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'cohnected to the system.' The units are Btu per hour or, in heating, equivalent.direct radiation (EDR). . ` 1M ' Load, Estimated Maximum: In a heating or cooling system, the calculated maxi mum heat transfer that the system will be called upon to provide. ... 1 Manometer; An.instrument for..measuring pressures;, essentially a U-tube par tially filled with a liquid, usually water^ mercury, or a light oil, so constructed that the amount of displacement of the liquid indicates the ptessiite being exerted on the instrument. ' . .. . ; .. .. _ Mass: A measure of the inertia of a body. It also measures the quantity of matter in a body. Since the only general property 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:equa! masses* or to contain equal quantities of matter.(This.definition fails at velocities approaching the veloc-. ity of light.) The mass of a body is numerically, equal to the ratio of the force re quired to give the body a given acceleration, to the acceleration; in = F/a. The common units of mass are the gram and the pound. f Mechanical Equivalent of Heat: The quantity of mechanical energy equal to one unit of heat. J = 778.3 ft-lb per Btu = 4.187 X 1,Q7 ergs per gram-calprie. 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. f , Micron: A unit of length, the thousandth part of 1mm or the millionth of a meter. Millimeter of Mercury: A. unit of pressure equal to.the pressure exerted by a column of mercury 1 mm high at a temperature of 0 C. One millimeter of mercury atOC = 1.934 X 10"* psi. .s . ......... ` . Mol: A weightof a substance numerically equal to its molecular weight. If the weight is in pounds the unit, is a Pound Mol, in grams the unit is. a Grom Mol. For perfect gases the volume of 1 mol is constant for all gases at the same temperature 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 steam vertically to a heat ing 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 beating 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 heating units is returned to the supply main. Consequently, the beating units far thest from the boiler are supplied with cooler water than those near the boiler in the' same circuit. : v; . . 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 transmitted 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 surface, and in tended to function essentially as a radiator. ' Perimeter System: See Warm Air Heating System. ` . Plenum Chamber: An air compartment maintained under pressure, and connected to one or more distributing ducts. : - ;. Terminology 7 Potentiometer: An instrument for comparing small electromotive 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 and 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 manometer which has one leg connected to the pres sure 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 co exist in stable equilibrium. ........................ Pressure, Static: The normal force per unit area that would be exerted by a mov ing fluid on a small 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 thermo-dynamic properties of a moving fluid depend on 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 confine ment over its liquid so that the vapor can accumulate above the liquid, the tempera ture being held constant , the vapor pressure approaches a fixed limit called the maxi mum, 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 equiva lent velocity, if applied to move the same fluid through an orifice such that all pres sure 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 proper ties of moist air. . . ' Psychrometry: The branch of physics relating to the measurement or determina tion of atmospheric conditions, particularly regarding the moisture mixed with the air. . . . - ....... - ' Pyrometer: An instrument for measuring high temperatures. Radiant Heating: A heating system in which only the heat radiated from panels is effective in providing the heating requirements. The' term1 Radiant Heating is fre: quently used to include both Panel arid Radiant Heating. . Radiation: The transmission of energy by means of electromagnetic waves. Radiation, Thermal (Heat) Radiation: The transmission of energy by means of electromagnetic waves of very long wave length. Radiant energy of any wave length may, when absorbed, become thermal energy and result in an increase in the tempera ture 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 objects within visible range, and by conduc tion to the surrounding 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. t. 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 transfersurface of the device, which may be either, a radiator or a convector, is not visible 8 CHAPTER 1 1954 Guide 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 radiator in which the heat transfer surfaces are principally tubes. Refrigerant: A substance which produces a refrigerating effect by its absorption ojLheat while expanding or vaporizing. 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 conductance. Symbol R. Resistivity, Thermal: The reciprocal of thermal conductivity. Symbol r. Resistor, Electric: A material used to produce heat by passing an electric current through it. Return, Dry: A return pipe in a steam heating system which carries both water of condensation and air. The dry return is above the level of the water line in the boiler in a gravity system. (See Return, Wet.) . Return, Wet : That part of a return main of a steam heating system which is filled with water of condensation. The wet return usually is below the level of the water line in the boiler, although not necessarily so. (See 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-Retum System: A system in which the heating or cooling medium from several heat transfer units is returned along paths arranged so that all circuits com posing the system or composing a major sub-division of it are of practically equal Sabin: A unit of equivalent sound absorption equal to the equivalent absorption of one square foot of 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 equilibrium 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 combustion, 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 earth's at mosphere. Sorbent: A material which extracts one or more substances present in an atmos phere 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 radia tors or convectors supplemented by mechanical circulation of air (heated or un healed) 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 heat ing unit and the top of the outlet opening. Steam: Water in the vapor phase. Dry Saturated Steam is steam at the satura tion temperature corresponding to the pressure, and containing no water in suspen sion. Wet Saturated Steam is steam at the saturation temperature corresponding to the pressure, and containing water particles in suspension. Superheated Steam is Terminology 9 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 heating units by means of steam at, above, or below atmospheric pressure. Steam Trap: A device for allowing the passage of condensate, or air and con densate, and preventing the passage of steam. / . Supply Mains: The pipes through which the heating medium flows from the boiler or source of supply to the run-outs and risers leading to the heating units. Surface, Heating: The exterior surface of a heating unit. Extended heating sur face {or extended surface): Heating surface consisting of fins, pins or ribs which re ceive 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 Heating Surface.) . Temperature: The thermal state of matter with reference to its tendency to com municate 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 mixture of gases indicated by an accurate thermometer after correction 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 sensation. . Temperature, Mean Radiant (MRT): The temperature of a uniform black en closure in which a solid body or occupant would exchange the same amount of radi ant heat as in the existing .nonuniform, environments . Temperature, Wet-Bulb: Thermodynamic wet-bulb temperature is the tempera ture at which liquid or solid water, by evaporating into air, can bring the air to satu ration 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, In struments and Apparatus, Part 18.) Therm: A quantity of heat equivalent to 100,000 Btu. 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: (l).When work.is expended.in generating heat, the quantity of heat 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 pro-r portional 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 all adiabatic paths connecting the two states. (Zemansky); (3) In any power cycle or refrigeration cycle the net heat 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 external 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 pro duce 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 temperature. . .. Transmittance, Thermal: The time rate of heat flow, from the fluid on the warm side to the fluid on the cold side, per (square Joot) (degree temperature difference be tween the two fluids). Sometimes called Overall Coefficient of Heat Transfer. . . Common unit is Btu per (hour) (square foot) (Fahrenheit degree). Symbol U. Names of authors who first stated laws are giveo in parentheses. From Glossary of Pkysics, by LeRoy Dougherty Weld (McGraw-Hill, 1937). 10 CHAPTER 1 1954 Guide 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 twopipe system is that each heating unit receives a direct supply of the heating medium, which medium cannot have served a preceding heating unit.- Up-Peed 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 atmos pheric pressure when desired. Vane Ratio: In air distributing devices the ratio of depth of vane to shortest open ing 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 operates under pressures at or near atmospheric and which returns the condensate to the boiler or receiver by gravity. Vapor 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 have a pressure-equalizing and air-eliminating device at the end of the dry- return. .. Velocity: A vector quantity which denotes at once the time rate and the direction of a linear motion. V = at For uniform linear motion V = -t* 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 known 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 1 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: vis cosity in centipoises X 0.000672 = viscosity in pounds per foot second, or viscosity in centipoises X 2.42 viscosity in 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 per cu cm per gram, or 1 sq cm per sec. For conversion to English 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 consists 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 circula tion 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 mo tive 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 combi nation panel and convection type. Warm air ducts embedded m the concrete slab of a basementless house, around the perimeter, receive heated air from a furnace 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. CHAPTER 2 ABBREVIATIONS AND SYMBOLS Standard Abbreviations; Standard Symbols; Greek Alphabet; Conversion-Equations; Graphical Symbols for Piping, Ductwork, Heating and Ventilating, Refrigerating; Identification of Piping by Color THIS chapter contains information regarding abbreviations, symbols, and conversion equations, which are of particular interest to the engi neer engaged in heating, ventilating, and air conditioning. ABBREVIATIONS Abbreviations are shortened forms of names and expressions employed in texts arid tabulations, and should not generally be used as symbols in equations. Most of the following abbreviations have been compiled from a list of approved standards.1 In general, the period has been omitted in all abbreviations, except where the omission results in the formation of an English word. Additional abbreviations applying to individual chapters will be found at the end of Chapters 3j 4} 13, 32, 36, and 47. Absolute.................... .*................... Air horsepower............................... Alternating-current (as adjective) Ampere........................................... Ampere-hour........................ .......... .... abs .air hp .......a-c .. amp amp-hr Atmosphere.. Average....... Avoirdupois.. Barometer... Boiling point .atm . .avg avdp bar. ...bp Brake horsepower.................... Brake horsepower-hour........... British thermal unit................. British thermal units per hour Calorie....................................... .. . bhp bhp-hr ... Btu .. Btuh .... cal Centigram...................................... Centimeter...................................... Centimeter-gram-second (system) Cubic.............................................. Cubic centimeter.......................... ........................... eg ...............cm ........................ CgB ...............cu cu cm or cc Cubic foot.................. Cubic feet per minute Cubic feet per second. Decibel........................ Degree*....................... Degree, Centigrade Degree, Fahrenheit Degree, Kelvin .... Degree, Reaumur... Diameter ............... .. cu ft .... cfm ....... cfs .........db deg or 0 . ,C . . . .F .. K .R diam ' and Engineering Terms, Z10.1-1941 {.American Standard. Auociaiian). ions , tha5 *he abbreviation (or the temperature scale, F. C, K, R, be included in expres- lor numerical temperatures but, wherever feasible, the abbreviation for degree be omitted, e.,,, 68 F. 11 12 CHAPTER 2 1954 Guide Direct-current (as adjective) Electromotive Force....... -. Feet per minute..................... Feet per second..................... Foot........................................ d-c emf fpm fps ft Foot-pound................................................................................................................. ft-lb Foot-pound-second (system)....................................................................................... fps Freezing point................................... .......:............... ............... .......................... - - - fp Gallon..................................................... gal Gallons per minute............................................... gpm Gallons per second................................................................................................ gps Gram............................................................................. ..... : :------ -------------........................... '. .-.g Gram-calorie..................................................... ........... . ,g-cal Horsepower............................................................................. hp Horsepower-hour............. hp-hr Hour................................................ hr Inch-.................................................................. in. Inch-pound........................................................... . .......................... . .. .in.-lb Indicated horsepower.....................................:......... .......... .....................ihp Indicated horsepower-hour...... ..................... ......... ............. .................;.ihp-hr Kilogram.............................................................................;----- .....:............... .. . kg Kilowatt........................... ....................................................................... ............... kw Kilowatt-hour...................................................... . r..................................... kwhr Mass.................................. ................................... .;............'....:......... '..:----- ; .mass Melting point............................................................................................................... mp Meter....................................................................................................... m Micron..................................................................... .,............................................P (mu) Miles per hour............................................................................................................ mph Millimeter................................................................................... mm Minute..........................................................................................................................min Molecular weight......... Mol................................. Ounce..................... Pound..................... Pounds per square inch Pounds per square inch, gage.... Pounds per square inch, absolute Revolutions per minute............... Revolutions per second................. Second........................................... mol wt' __ mol .......oz .......lb ___psi psig psia rpm .rps .sec Specific gravity............................................................... Specific heat.................................................... sp gr sp ht Square foot................................................. sq ft Square inch................ .............................................................................................sq in. Watt............................................................................................................................... w Watthour.....................................................................................................................whr SYMBOLS A letter symbol is a single character, with subscript or superscript if required, used to designate a physical magnitude in mathematical equa tions and expressions. Two or more symbols together always represent a product. The following have been compiled from a selected list of approved standards.3 Additional symbols and variations in the standard symbols Letter Symbols for Mechanics of Solid Bodies, Z10J-1942, and Letter Symbols for Heat and Thermo dynamics, Z10.4-1943 (American Standard) Association). Abbreviations and Symbols . 13 found necessary in the individual chapters will be found in a list at the end of Chapters 3, 4,13, 32,36, and 47. Acceleration, due to gravity..........................................................................................g Acceleration, linear.............................................. ...................................'................... a Area............................................... V.....'.................................................................................................. A Change in specific volume during vaporization,. .......................... ...................... ..vtt Density, Weight per unit volume, Specific weight.................................... d or p (rho) Distance, linear.......................................... .................1..................................................s Dry saturated vapor, Dry saturated gas at saturation pressure and temperature, vapor in contact with liquid................................................................. Subscript g Efficiency........... V................. .................... ....................................... i; Elevation above some datum..................'!....... ....................................................... z, Z Emissivity....................................................................... i Energy in general; work, total; work, molal.............................................................. 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 pV = nRT..................... R Head.................................................. ......................... ............................ ......... H or h Heat content, Total heat, Enthalpy, (The capital should be used for any weight and the small letter for unit weight).____ V................................... H or h . Heat content of saturated liquid, Total heat of saturated liquid. Enthalpy of saturated liquid, sometimes called heat of the liquid............ .......... ................ ht Heat content of dry saturated vapor. Total heat of dry saturated vapor, En thalpy of dry saturated vapor................................................................................ft* Heat of vaporization at constant pressure........- . ................................. /, or htt Hydraulic radius............................................................................................................Rb Internal energy. Intrinsic energy. (The capital should be used for any weight and the small letter for unit weight)........................................................... U 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.... ..................... p 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 mixture..................................x Reynolds Number........................................................................................................ JVr, Saturated liquid at saturation pressure and temperature. Liquid in contact with vapor......................................................................................................... Subscript f Specific heat:.................. ........................;.................... ;...:..................................... c Specific heat at constant pressure...................................... .................... . . . .............. cP Specific heat at constant volume. -.............................................................................c* Specific volume. Volume per unit weight, Volume per unit mass............ ................ Temperature (ordinary) F or C, (Theta is used preferably only when t is used for Time in the same discussion)........................................................ tor (theta) Temperature (absolute) F abs or K. (Capital theta is'used preferably only when small theta is used for ordinary temperature)......................T or 6 (capital theta) Thermal conductance:* heat transferred per (unit time) (degree)............... ........... C C=I= 4 R Jj ti -- ta . ' 4 Terms ending ivtiy designate properties independent of size or shape, sometimes called specific proper ties. Examples: conductivity, resistivity. Terms ending ance designate quantities depending not only on the material, but also upon sue and shape, sometimes called total quantities. Examples: conductance, transmittance. Terms ending ion designate rate of heat transfer. Examples: conduction, transmission. 14 CHAPTER 2 1954 Guide Thermal conductance per unit area, Unit conductance : heat transferred per (unit tiine) (unit area) (degree)...........................................................;............C C = = _L 9 = * * A RA A(U - Q L ' . Thermal conductivity: heat transferred per (unit time) (unit area) (degree per unit length)...............................................................................................................k . J7 . (h -- la) L Surface coefficient of heat transfer, Film coefficient of heat transfer, Individual coefficient of heat transfer: heat transferred per (unit time) (unit area) (degree).....................................................................................................................f 9 A / = !i - t. (In general / is not equal to k/L, where L js the actual thickness of the fluid film.) Overall coefficient of heat transfer. Thermal transmittance per unit area: heat transferred per (unit time) (unit area) (degree overall)............................ ........ U Thermal transmission (heat transferred per unit time)..............................................9 Q q^T - Thermal resistance (degree per unit of heat transferred per unit time)................. R Thermal resistivity....................................................................................................... 1A ' Vaporization values at constant pressure. Differences between values for satu rated vapor and saturated liquid at the same pressure....................Subscript fg Velocity............................................................................................................................ T Viscosity, absolute...........................................................................................................M Viscosity, kinematic..................................................................................................... p/p Volume (total)......................................................................... ...................................... V Volume per unit time. Rate at which quantity of material passes through a machine, Quantity of heat per unit time, Quantity of heat per unit weight... 9 Weight of a major item, Total weight........................................................................ Weight rate, Weight per unit of power, Weight per unit of time....... I................... Work (total)................................................................................................................... THE GREEK ALPHABET A a Alpha B/S Beta r 7 Gamma a a Delta E e Epsilon Zf Zeta H, Eta eoe Theta I i lota K k Kappa A X Lambda M p Mu N v Nu E Xi 0 o Omicron n ir Pi P p Rho 2 a s Sigma T r Tau T v Upsilon 4> <p <(> Phi Xx Chi ik & Psi U o} Omega Abbreviations and Symbols 15 CONVERSION EQUATIONS6 Heat, Power and Work 1 ton refrigeration Latent heat of ice 1 Btu .. 1 Int. watthour 1 Int. kilowatthour 1 Int. kilowatt (1000 watts) 1000 I.T. calories) 1 I.T. Kilocalorie) 1 horsepower 1 boiler horsepower Weight and Volume ( 12,000 Btu per hour \ 200 Btu per minute = 143.4 Btu per pound 778.3 ft-lb 0.2930 Int. whr 252.0 I.T. calorie ( 2656 ft-lb I 3.413 Btu | 3600 Int. joules (860 I.T. calories ( 3,413 Btu I 3.517 lb water evaporated from l and at 212 F 1.341 hp 56.88 Btu per minute AA 00*7 ri if . 3.968 Btu = 3088 ft-lb 1.1628 Int. whr ( 0.7455 Int. kw _ I 42.40 Btu per minute ~ 1 33,000 ft-lb per minute l 550 ft-lb per second f 33,475 Btu per hour \ 9.809 Int. kw - 1 gal (U. S.) 1 British or Imperial gallon 1 cu ft 1 cu ft water at 60 F (in vacuo) 1 cu ft water at 212 F (" " ) 1 gal water at 60 F (" " ) 1 gal water at 212 F (" " ) 1 lb (avdp) 1 bushel 1 short ton Pressure ) 231 cu in. ~ \ 0.1337 cu ft = 277.42 cu in. / 7.481 gal = \ 1728 cu in. = 62.57 lb = 59.83 lb = 8.338 lb = 7.998 lb _ f 16 oz ~ \ 7000 grains = 1.244 cu ft = 2000 lb . 1 lb per square inch 1 oz per square inch 144 lb per square foot 2.0360 in. 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 0.1276 in. mercury at 62 F 1.732 in. water at 62 F Abbreviations Int. and I.T. refer to /nlemottonol 16 1 atmosphere CH!AP' TER 2 1954 Guide -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 l 29.921 in. mercury at 32 F 1 in., water at 62 F (in vacuo) 0.03609 lb per square inch 0.5774 oz per square inch 5.197 lb per square foot 1 ft. water at 62 F (in vacuo) f 0.4330 lb per square inch ( 62.37 lb per square foot 1 in. mercury at 62 F (in vacuo) { 0.4897 lb per square inch 7.835 oz per square inch 1.131 ft water at 62 F 13.57 in. water at 62 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 Bq cm 1 sq in, 1 sq m 1 sq ft 1 cu cm 1 cu in. 1 cu m 1 cu ft 1 liter 1 kg lib 1 metric ton 1 gram 1 kilometer per hour . 1 gram per square centimeter 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 = 0.02832 cu m = 1000 cu cm = 0.2642 gal = 2.205 lb (avdp) = 0.4536 kg = 2205 lb (avdp) = 0.002205 lb (avdp) = 0.6214 mph _ / 0.02905 in..mercury at 62 F -- ^ 0.3942 in. water at 62 F 1 kg per sq cm (metric atmosphere) 1 gram per cubic centimeter = 14.22 lb per square inch 0.03613 lb per cubic inch 62.43 lb per cubic foot 1 dyne 1 absolute joule ' = 0.00007233 poundals 10,000,000 ergs 0.7376 ft-lb 1 Int. joule 1 metric horsepower = 0.7378 ft-lb 75 kg-m per second 0.986 hp (U. S.) . 1 I.T. kilocalorie per kilogram 1 I.T. calorie per square centimeter = 1.8 Btu per pound = 3.687 Btu per square foot 1 I.T. calorie per (second) (square centi meter) for a temperature gradient of 1 deg per centimeter C = ( ] l 2903 BTU per (hour) (square foot) for a temperature gradient of 1 F deg per inch of thickness. Abbreviations and Symbols 17 GRAPHICAL SYMBOLS FOR DRAWINGS' Graphical Symbols for Drawings Heating Piping 1. High Pressure Steam -----*-- 2. Medium Pressure Steam 3. Low Pressure 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 Oil Tank Vent 15. Compressed Air ' 16. Hot Water Heating Supply 17. Hot Water Heating Return -FOF--FOR-- --FOV-- Air Conditioning ' 18. Refrigerant Discharge 19. Refrigerant Suction 20. Condenser Water Flow 21. Condenser Water Return 22. Circulating Chilled or Hot Water Flow 23. Circulating Chilled or Hot Water Return 24. Make-Up Water 25. Humidification Line 26. Drain 27. Brine Supply 28. Brine Return --------------------- -rd----------------------- --:-----------rs------------- -- -------------------C--------------------- -----------------------CR----------------------- -- -- CH H- -D- Pujmbing 29. Soil, Waste or Leader (Above Grade) 30. Soil, Waste or Leader (Below 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 '' --------------------------------------------------------------------- -- ----------------------- f---------------- e------------ ~A!2_ ------------------------------------ .-----V-----------------a-- Sprinklers 42. Main Supplies 43. Branch and Head 44. Drain ` Extracted from: American Standard Graphical Symbols for Pipe Fittings, Valves, and Piping (ASA Z32.2.3-1949) and American Standard Graphical Symbols for Heating, Ventilating, and Air Conditioning (ASA Z32.2.4-1949) with the permission of the publisher, The American Society of Mechanical Engineer?, 29 West 39tb St.. New York 18, N. Y. 18 CHAPTER 2 Graphical Symbols for Drawings 1. Air Eliminator 2. Anchor . 3. Expansion Joint 4. Hanger or Support 5. Heat Exchanger 6. Heat Transfer Surface, Plan (Indicate Type Such as Convector) 7. Pump (Indicate Type Such as Vacuum) 8. Strainer 9. Tank (Designate Type) 10. Thermometer 11. Thermostat 12. Traps 12.1 Boiler Return 12.2 Blast Thermostatic 12.3 Float 12.4 Float and Thermostatic 12.5 Thermostatic 13. Unit Heater (Centrifugal Fan), Plan 14. Unit Heater (Propeller), Plan 15. Unit Ventilator, Plan 1954 Guide Heating -E3- 6=6 0-0 0D n -<fcj Abbreviations and Symbols Graphical Symbols for Drawings 16. Valves 16.1 Check . 16.2 Diaphragm 16.3 Gate 16.4 Globe 16.5 Lock and Shield 16.6 Motor Operated 16.7 Reducing Pressure 16.8 Relief (Either Pressure or Vacuum) 17. Vent Point 19 Heating WX- t>b <E> -VENT Graphical Symbols for Drawings 18. Access Door 19. Adjustable Blank Off 20. Adjustable Plaque 21. Automatic Dampers Ventilating -AD GL TR 20X12 "Pp-aoxi2-7oocpm 3 3 P-20V-700 cfm -w---------- ^ 22- Canvas Connections 20 CHAPTER 2 Graphical Symbols for Drawings 1954 Guide Ventilating 23. Deflecting Damper V fel 24. Direction of Flow 25. Duct (1st Figure, Side Shown; 2nd Side not Shown) 26. Duct Section (Exhaust or Return) 27. Duct Section (Supply) 28. Exhaust Inlet Ceiling (Indicate Type) 29. Exhaust Inlet Wall (Indicate Type) 12 X 20 3 [ZMe OR R 20X 12) f><3------------(S 20 X 12) lCR 20 X 12 - 700 Cfm Jcg^oxTIT- 700 c^m h-- TR-I2*S 7ooc^m 30. Fan and Motor With Belt Guard 31. Inclined Drop in Respect to Air Flow 32. Inclined Rise in Respect to Air Flow Jf----ir 33. Intake Louvers on Screen 34. Louver Opening 35. Supply Outlet Ceiling (Indicate Type) | L 20 >$12-700 CfH (^) 20* D1AM. 1000 Cf m 36. Supply Outlet Wall (Indicate Type) 37. Vanes 38. Volume Damper Abbreviations and Symbols Graphical Symbols for Drawings 39. Capillary Tube -- VWW~ 40. Compressor R 41. Compressor, Enclosed, Crankcase, Ro tary, Belted ' o 42. Compressor, Open Crank case, Recipro cating, Belted s=\ 43. Compressor, Open Crank case, Recipro cating, Direct Drive 44. Condenser, Air Cooled, Finned, Forced Air 45. Condenser, Air Cooled, Finned, Static 1 TI 4- 46. Condenser, Water .Cooled, Concentric Tube in a Tube I- 47. Condenser Water Cooled,-- Shell and Coil * -- r* 48. Condenser, Water Cooled, Shell and Tube 49. Condensing Unit, Air : -gp6_ Cooled -6150. Condensing Unit, Water Cooled 51. Cooling Tower 52. Dryer 53. Evaporative Condenser 54. Evaporator, Circular, Ceil ing Type, Finned 55. Evaporator, Manifolded, Bare Tube, Gravity Air 56. Evaporator Manifolded, Finned, Forced Air OOO oO Oo oo K>ooo ooo ooo,l 21 Air Conditioning 57. Evaporator Mani folded, Finned, Gravity Air 58. Evaporator, Plate Coils, Headered or Manifold 59. Filter, Line 60. Filter & Strainer, Line oo o oo oo oo 61. Finned Type Cool ing Unit, Natural Convection 62. Forced Convec tion Cooling Unit 63. Gage c *--iijiii ) ) 3D 2 64. High Side Float 65. Immersion Cool ing Unit 66. Low Side Float 67. Motor-Compres sor, Enclosed Crankcase, Reciprocating, Direct Connected 68. Motor-Compres sor, Enclosed Crankcase, Rotary, Direct Connected e-6 - uaoc, eating 70. Motor-Compres sor, Sealed Crankease, Rotary "V\Ar{p)-Wr-- 72. Pressure Switch 73. Pressure Switch With High Pressure Cut-Out 74. Receiver, Horizontal 75. Receiver, Vertical -da -dEb- 0- 22 CHAPTER 2 1954 Guide 76. Scale Trap 77. Spray Pond -0- 80.6 Evaporator Pressure Regulating, Throt tling Type (Evapo rator Side) 80.7 Hand Expansion -6^ & 78. Thermal Bulb 79.,Thermostat (Remote Bulb) 80. Valves 80.1 Automatic Expan sion 80.2 Compressor Suction Pressure Limiting, Throttling Type (Compressor Side) 80.3 Constant Pressure, Suction 7r aC5- 80.4 Evaporator Pressure Regulating, Snap Action 80.5 Evaporator Pressure Regulating, Thermo static Throttling Type -<- 80.8 Magnetic Stop 80.9 Snap Action 80.10 Suction Vapor Regulating 80.11 Thermo Suction 80.12 Thermostatic Ex pansion 80.13 Water 81. Vibration Absorber> Line 5" 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 in Fig. 1, is reprinted from Part V, Fourth Edition, of the Engineering Standards of the Heat ing, Piping and Air Conditioning Contractors National Association.7 Class Color F--Fire-protection D--Dangerous materials S--Safe Materials Red Yellow or Orange Green (or the achromatic colors, white, black, gray or aluminum) and, when required P--Protective materials V--Extra valuable materials Bright blue Deep purple Fig. 1. Main Classification by Color 7 See Scheme for Identification of Piping Systems, A13-192S, American Standards Association. 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; A.S.H.V.E. Psychrometric Chart; Solution of Air Conditioning Problems by Use of Tables and Psychrometric Chart; U. S. Standard Atmosphere THERMODYNAMICS is that branch of natural science which deals with energy and its transformations into various forms. In this chap ter the discussion will be limited to thermodynamics as it affects the arts of heating and air conditioning. This will necessarily presume some knowledge of the fundamentals of the science on the part of the reader who may also find it desirable to refer to a standard text on the subject, preferably one published after 1930. MASS AND ENERGY BALANCES The First Law of Thermodynamics is a statement of the Principle of Conservation of Energy. It may be stated as follows: The energy added to a system is equal to the increase or decrease of the energy stored in the system, plus the energy which leaves the system. For a completely contained, or non-flow system, this may be restated as: The heat added to a non-flow system is equal to the change in the internal energy of the system, plus the work done by the system. iq. = U, - U, + w (1) For a constant pressure process ,q* = H, - H, (2) where iqi = 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 syBtem between which a change takes place. 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 boundaries 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 crossing 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 23 CHAPTER 3 1954 Guide 24 velocity, and energy in the form of enthalpy. Additional energy may cross lie 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 Thermody namics': ` -' PEi 4- KEi -f- Hi 4- i<71 = PEt 4- KEi 4- Hi 4- w (3) where PE -- potential energy, Btu per pound dry air. KE = kinetic energy, Btu per pound dry air. H = enthalpy, Btu per pound dry air. ,qt = heat added between sections 1 and 2, Btu per pound dry air. w = shaft work withdrawn between sections 1 and 2, Btu per pound of dry air. 9 Fio. 1. Energy Change between Two Sections op a System For most psychrometric problems, since the change in the potential energy and kinetic energy terms is negligible compared to the enthalpy change, Equation 3 may be simplified to Hi 4- iQt -- Hi 4- ic ' (4) where H = enthalpy of the flowing medium, Btu per pound of dry air. , The enthalpy of the entire system may be broken down into constituent parts, thus: GH - Gh + LKi 4- Sh,, (5) where h = enthalpy of moist air, Btu per pound of dry air. hwt -- enthalpy of liquid water, Btu per pound. h,, = enthalpy of solid water, Btu per pound. L = flow rate of liquid water, pounds per hour. 5 = flow rate of solid water, pounds per hour. 6 = flow rate of dry air, pounds per hour. ' Thermodynamics 25 Similarly, an equation expressing the conservation of mass may be written thus: where 1G(1 4- BO + L 4- S] = [(7(1 4- W) + L + SI to oat (0) IF = humidity ratio, pounds of water vapor per pound of dry air. THERMODYNAMIC PROPERTIES OF MOIST AIR The working substance of the air conditioning engineer is moist air. Air is actually a mixture of oxygen, nitrogen, carbon dioxide, water vapor, and traces of other gases. 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 water vapor varies considerably. To allow for this variation the specific properties of moist air are developed in terms of the 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 humidity, degree of saturation, dry-bulb temperature, thermodynamic wet-bulb temperature, and dew-point temperature. These terms are defined in following paragraphs. Humidity 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 humidity, 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 saturated air at the same dry-bulb temperature and barometric pressure. Degree of Saturation. Ratio of the actual humidity ratio to the humid ity ratio of saturated air at the same dry-bulb temperature arid barometric pressure. Relative humidity and degree of saturation are related according to the identity: (7) where . <t> = relative humidity, expressed as a decimal. . ii = 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 units as P.. /. = a dimensionless factor which may be regarded as accounting for influences arising when air and water are intermixed. Magnitudes of /, have been reported by Goff and Gratch' and by Goff.* Table 1 gives values of /,, for a limited range of conditions. 26 CHAPTER 3 i- 1954 Guide 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. Thermodynamic Wet-Bulb Temperature. The temperature at which liquid or solid water, by evaporating into air, can bring the air to'satura tion adiabatically at the same temperature. . Consider an adiabatic system as shown in Fig. 2. Unsaturated air at the state ft,, W,, enters the system at section 1, and saturated air at the state h*, W*, leaves the system at section 2. Liquid water at the state h,*, corresponding to the temperature of the saturated air leaving the system is supplied. Then, since no work is done and the system is strictly adiabatic, the energy equation becomes A,'+ (W*- Wx)h,,* = A* (8) where * indicates condition at thermodynamic wet-bulb temperature. 1. ft 0 125 FTable Magnitudes op fob the Range to (Standard Barometric Pressure, 29.921 in. Hg) Temp. F Temp. F fs 0 10 20 30 40 50 60 1.0048 1.0046 1.0046. 1.0045 1.0044 1.0044 1.0044 70 1.0045 80 1.0047 90 1.0048 100 1.0050 110 1.0053 120 1.0055 125 1.0057 Note The original source' given /. to seven significant figures over the temperature range -208 F to 202 F and over the pressure range 20 to in. ng. The temperature corresponding to h* for given values of A and IF, is called the thermodynamic wet-bulb temperature, or the temperature of adiabatic saturation. ' The temperature indicated by an ordinary wet-bulb thermometer 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 (a) radia tion 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 pos sible the calculation of the true thermodynamic wet-bulb temperature from observed data through the use of suitable corrections to be applied to the readings of the wet-bulb thermometer. However, unless extreme precision is required, the observed temperature may be taken equal to the theoretical temperature for most engineering 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 corresponding 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 Thermodynamics 27 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 mathe matical expressions and came to be regarded as physical laws. However, as scientific knowledge increased, and as more precise methods of measure ment were developed, it became apparent that these simple equations did not describe the behavior of the mixtures of actual gases and vapors ac curately. The original statements have been found to be useful tools, nevertheless, in many cases. For example, the behavior of common diatomic and tria- <P N.w. 1 ' V/Vp. I h,,W, I Y/V/r `V777777777777V. (Wj-W,). N, Fig. 2. Illustration of Adiabatic Saturation _ 0___ __ ____ iv.i.uwa uicse equations cioseiy enougn so that they may be used for some types of engineering problems. The practice of engineering is an art, and not an exact science, and many useful engineering works have been constructed through the use of approxima tions. The degree of approximation, however, which may be tolerated in engineering design must be decided by the engineer, based upon his study and experience in the field. Boyle's Law. One of the original observations of the physical behavior of gases was made by Robert Boyle who noted that, if a constant weight of gas is compressed with the temperature held constant, the volume V varied inversely as the absolute pressure P. Stated mathematically, PV = constant (temperature constant) (9) Charles' Law. Experiments made independently by Charles and GayLussac 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, the absolute pressure P varies as the absolute temperature T; if a constant weight of 28 CHAPTER 3 1954 Guide gas is heated or cooled at constant pressure, the volume V varies as the absolute temperature T. Stated mathematically, p -- = constant (volume constant)... (10) V -- = 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. Dalton's Rule. Dalton stated that each gas in a mixture occupies the total volume of the mixture just as though the other gases were not present. Gibbs later expanded this statement for perfect gases into the following principles: 1. The pressure of a mixture of gases is the sum of the partial pressures of the in dividual 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 respec tively 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 mix ture. While these relationships do not hold exactly for all systems of real gases, they may be used with a good degree of precision for many engineer ing applications at low pressures. Moreover, since water vapor very closely follows the perfect gas relationships in the range usually encountered in air conditioning, the Gibbs-Dalton Rule may frequently be applied to mixtures of dry air and water vapor. Thus, (13) fe ll Q fe ll = T* = Tw ' = P + Pw = m,.ft. + m.ft (14) (15) (16) where Subscript m denotes mixture; subscript a 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: nJtT Vm ------------ n,RT (n. + nw)RT ----------- ----------------------------- P* V (,17J where vr = total volume, cubic feet, n, = number of mols of dry air. Thermodynamics 29 li = universal gas constant, 1545 foot-pounds per (Fahrenheit degree) (mol). = partial pressure of dry air. p,, = partial pressure of water vapor. T = absolute temperature, Fahrenheit degrees. The partial pressure of water vapor in the mixture is then n. + n, P (18) 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 satu rated mixture may be written as where n. p = n, -f n. (19) n = number of mols of water vapor at saturation. The relative humidity may be obtained by combining Equations 18 and 19 and solving for the ratio of mol fractions. Thus, using perfect gas relationships, P. The humidity ratio W may be obtained from Equation 17: (20) w 18.016 p. ,, ,,w W ---------- -- -- flfioo 28.966 p. p - p. (21) where 18.016 and 28.966 are the molecular weights of water and dry air, respectively. Equation 16 may be rewritten as where h = ft. + WK (22) 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 zero enthalpy point. Accordingly, from perfect gas relationships, it is possible to write for any temperature of t, Fahrenheit greater than OF ' ft, = 0.24 t (23) where it is assumed that the same arbitrary datum of 0 F is used as in determining the properties of moist air in Table 2. Tabs of Thermodynamic Properties of Moist Air Research work conducted at the University of Pennsylvania and at other institutions has shown that the Gibbs-Dalton Rule is inaccurate in varying degrees, depending on temperature, pressure and the amount of water 30 CHAPTER 3 1954 Guide vapor present. The probable reasons for this inaccuracy are due to the effect of: . 1. Chemical solution of gas molecules in the water vapor. 2. The finite size of the molecules causing interference with the free passage of other molecules toward the boundaries of the system. 3. Intermolecular forces of attraction and repulsion. Many attempts have been made to develop an equation of state 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 com plicated 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 steam. 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 co operative research agreement between the American Society op Heating a.nd Ventilating Engineers and the Toume 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.4 Table 2, which experimentally and mathematically takes into account deviations from perfect gas behavior, such as those listed above, makes the applica tion of the Gibbs-Dalton Rule a less frequent necessity. In Table 2 there are 15 columns of figures, each column being headed by a suitable symbol. In the following sub-paragraphs brief explanations are given of the data in Table 2 under the appropriate column headings. i(F) = Fahrenheit temperature defined in terms of absolute temperature T by the relation, T = t + 459.69 (24) Absolute zero of temperature may be defined as the receiver temperature which will enable a Carnot Cycle engine to transform into work all the energy it receives in the form of heat. W, -- humidity ratio at saturation. Saturation is the condition at which the vapor phase (moist air) may exist in equilibrium with a condensed phase (liquid or solid) at the given temperature and pressure (standard atmospheric pressure m the case of Table 2). At given values of temperature and pressure, the humidity ratio W can have any value from zero to Wa. . = specific volume of dry air, cubic feet per pound. v* = v, -- the difference between the 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 pouhno d=osfpdercyifiacier.nthalpy 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. . h h, -- ft., the difference between the enthalpy of moist air af saturation, per pound of dry air, and the specific enthalpy of the dry air itself, Btu per pound of dryh.ai=r. enthalpy of moist air at saturation per pound of dry air, Btu per pound of drysnai=r. specific entropy of dry air, Btu per (pound) (Fahrenheit degree). It will be Thermodynamics 31 noticed that the specific entropy of dry air has been assigned the value zero at 0 F and standard atmospheric pressure. s,, = 8. -- 8b, 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). air8)b(=Faehnretrnohpeyitodf emgoreiset).air at saturation per pound of dry air, Btu per (pound of dry hw = 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 (0.088586 psia). s,, = specific entropy of condensed water (liquid or solid) at standard atmospheric fpimsqieuaa)ids. uwrea, tBertuhapsebre(epnoausnsdignoef dwtahteerv)al(uFeazhereronhaetit32deFg,resea)t.uraTthioensppreecsisfiucreen(t0r.o08p8y58o6f p. -- saturation pressure of pure water vapor, pounds per square inch or inches of Hg (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 dis solved air. On the other hand, pure water vapor (steam) below the critical tempera ture, can be saturated at only one temperature for a given pressure. The values of asnadtuGrartaiotcnhp. ressure listed in Table 2 have been computed from the formulas of Goff 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 the temperature within these limits. Therefore, the enthalpy of the water vapor may be expressed as being approximately equal to the enthalpy of saturated vapor at the dry-bulb temperature of the mixture. Substituting these values in Equation 22, the enthalpy of the mixture becomes h = 024 t + Wh. (25) where he 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 extensions downward to --160 F. These revisions and extensions were a necessary preliminary to the construction of Table 2. A detailed explanation of the methods employed in the construction of Table 3 is given in a paper by John A. Goff and S. Gratch.* As in Table 2, the temperature scale used as argument in Table 3 is the Fahrenheit scale defined in terms of absolute temperature T by Equation 24. The symbols used as column headings in Table 3 are the same as those used in steam tables, and have the same meanings. Properties of water above 212 F from Keenan and Keyes* are given in Table 4. DEGREE OF SATURATION 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 drybulb temperature and barometric pressure. This may be stated mathe matically as rr , Obviously the degree of saturation p can have any value from zero (dry air) to unity (moist air at saturation). The degree of saturation is con- CHAPTER 3 1954 Guide 32 fPscSHa*f-~ev 21S11S1 S1S1S1S1 S1 S1 21S1 s1sss ssss ssss ssss -.0 w z -1 t.sOsszHZOo 4iawfml.xo,, Ilii - wggot-*3- ini tttt iIgl't'josi ssks III! Ill mnf?i m*???i? ;sss ssss WW Iff? Ilis iiis sim mani mi ill ss;s ssss ss?^ Iff? !t!t T7T7 m HI! lii siii ^5 7777 7777 SSH--3S5fi' .'S''. iill!i lliihii nanil Si!!!!ii IiIlIiIi i111i1 !i!!!! 1??1?1? 11 1??1?1? l!!I irlnii III :- g< CO . SHPD* ' 1?1ft1?111111111. S11i1l1l H1111i ITITITIT I1I1I1I1 H-IT?i iTTlTl? M * ills Slls ills iTi^iTsf TTssTT ITTlTiiT lTls7T' sss WS5JCsPH3Q 3e j!S!!! Jill 111! ill IIII IIII IS < I*fllsf^ siii inllf!f T1TST3T 8T1T8T5T 5T5TST3T sTSTTl* *"' H c4 sgost53Bf ' 5 1 s' IBS IIII rn si HiS ISIS SI ill! 111! m IBs MIS SMI Ills ills SHI mm Si IS S Sill 11 ISIS H f9scK8-<A&x` 1do1d1o! idoldlo ioololo Sooo5o 0h<** g|| Hg fe! 9B . 3mSmI3 S1 31S1 a1-'S1S1S131 1 ff*? TTTT TTTT TTTT ^TTT b y Jo h n A . G o ff a n d S. C o m p ile d b y Jo h n A . G o ff and S. G ra tch . Thermodynamics 33 =S:!iS 5.1339 2$8e$ 8S22 neixo Mil MM I M i 7777 3.5720 3.7845 4i .l1785i 2.8886 3.0472 . 3.2137 3.3885 2.3272 2.4573 2.5940 2.7377 -0.3346 . 2.2035 2.0869 1.9740 1.8677 1.4929 1.6795 1.6706 1.7688 . 1.1219 1.2687 1.3327 1.4107 0.70048 0.78028 0.68838 . 0.99866 ' aaOrt s 0 ss 1 0u2*3M5. da O.~*.1 s -0.3254 -0.3244 -0.3234 -0.3223 =8:1151 -0.3295 -0.3285 -0.3275 -0.3264 -0.3336 -0.3326 -0.3316 -0.3305 -0.3357 -0.3367 -0.3377 -0.3418 -0.3408 -0.3398 -0.3387 -0.3469 -0.3449 -0.3439 -0.3428 -0.3552 -0.3531 -0.3511 -0.3490 E n tro p y B tu/Lb (F) flw >5m 01az 3ft 4 4* 0Qa 4 *< 1 .O a gs Zb* D5K 6 E nthalpy B tu/Lb Aw ssss S 1ii1 sass-asss gsss 2S22 2222SSSS mm 1 1 1 1 1 1T7 ssss sass S5s sssg S3SSS 3SSS ggSB BBgg TTTT TTTT TTTT TTTT 0.00036 0.00043 0.00048 0.00054 0.00061 0.00068 0.00072 0.00076 0.00080 0.00084 0.00089 0.00094 0.00099 0.00104 0.00109 0.00115 0.00121 0.00128 0.00136 0.00142 0.00149 0.00157 0.00165 0.00174 0.00183 0.00192 0!00212 3 * -0.01683 -0.01468 -0.01350 -0.01233 -0.01118 -0.00999 -0.00940 -0.00882 -0.00824 -0.00766 -0.00707 -0.00649 -0.00590 .-0.00532 -0.00473 -0.00414 -0.00354 -0.00294 -0.00234 -0.00174 -0.00114 -0.00053 0.00008 0.00069 0.00131 0.00192 0.00254 0.00316 0.00379 0.00442 o:K :888581 0.00260 0.00312 j -0.01621 -0.01609 -0.01398 -0.01287 -0.01177 -0.01067 -0.01012 -0.00958' -0.00904 -0.00850 -0.00796 -0.00743 -0.00889 -0.00836 -0.00582 -0.00529 -0.00475 -0.00422 -0.00369 -0.00316 -0.002630.00210 -0.00157 -0.00105 -0.00052 0.00000 0.00052 0.00104 ................ .... ii i i i i IS S8l fill SO OO ---- -- 22s* ** * slsl IgSS gill Sl|3PJa > ION050 OOCDQOa e*c> ta. ____ _ S3 oooo oooo oooo oood dddd dddd dddd d!L' NOegMr-ctO^>ititoc-. <0DtO <mcwowoctt- 2 N> COOOCOO dddd ^5 ~2--s- I 3138 Sis; ii ittT ? Ii3S Ills Ssll gggg 2H S 222 So oooo oooo o22 S2WM '*oo> Nae s 2222 2222 2222 oooo oSoo oooo oooo SSSS oooo oooo oooo o d o' o' dddd WddWdftd o=S= --oI 2 NW OP 3SII 3gg ===*= =;=; ===; fc 02 2S~ >ooo eak- ISIS Ilsz oooo PS (C^ 58b S22 >li< Mil 7777 CHAPTER 3 1954 Guide 34 isCOOO *" C4 e* ta SSSS SSSS SS" SSSS SSSK ms, 29.921 i n . Ho) (Continued) * a. SSSS SSt.. 111 llll list sill SHE 32*1 ssss SSSS 3 . oo- ^222 ^222 2SSS5 1 dtSVc-t ft. > ir Kaoj^ O'-'fr, 5 C..4.C..3.*}- Is! III! 111! III! sill 1111 fill 1m ??t? ??? mi mi ???? im oooc> ssss ssss ssss sss sss ggss C g -C tTTT 7777 7s7s7ss7' S-7r7Sr7-srS7r 77$T7=T7=7=77VE77s7Ts,Ts T2.,TS,~ s as.gOO g00g0=g0;' III fill III ill 1111 III ) OO O OOOO 0*000* oooo oooo oooo oooo oooo o S*55ii2g21 SsSSSg ill ill ill ill it ill ooo;SoooSooo?ooo5 2oo2oo2ogog2oo oooo oooo OOOO oooo oooo oooo I & 1 1 j >a <a Wp ! o3 >e o o o o OOC sill 111'III fill 111! Ill oooo oooo OOOO 00*00 oooo* 0*000* !2SS 3*31 *333 3335 333* fill " <22S =7=2 2222 llll 151 iSIs nEgjj 33 jj33 IOC* <9 0 OO -- ^ iii mm mm 3333 =| Sill III! Ills 3**3 Isis SHI Ills list ==== ==== =222 2222 2222 2222 2222 2222 SS00 oooo 0008 oooo sill 00*00 11=1 o oo iS oooo ill! oooo slsl oooo llll oooo llll IIES SS33 8333 1115 Ills ==22 2222 2222 2222 2222 2222 S o* 2B,, fr* BS o-^. s set, < is Hill igil 333 3333 3j?j$jj 3111 22 222= 2SSS SSSS SSSS 5SSS SSSS Thermodynamics 35 X e> --- < Sfe SS5= 5535 22=?. SSSS SSSS SggS SSSS SSSS V a p , Press In. Hg P E ntropy Btu per (F) {lb dry a ir ) T h e r m o d y n a m ic P r o p e r t ie s o f M o is t A i r * (S t a n d a r d A t m o s p h e r ic P r e s s u r e , 29.921 i n . Ha) (Continued) CONDENBED WATER 111 111 III III llll ill ill llll oooo oooo oooo oooo oooo OOOO OOOO oooo >>.0 <* iiii mi iiii mi iiii iiii mi mi a = gggg g22S 2=== ===2 2222 2222 222= ==== 2 = 22 =222 22S SSSS SSSS SSgS SSSS E nthalpy B tu/Lb hw 1 1 S ill ini . in ini ini mi in ill OOOO - OOOO OOOO OOOO* 0*000 OOOO OOOO OOOO *3 ` ill III III ill ill-ill ill ill OOOO OOOO OOOO OOOO OOOO OOOO OOOO OOOO a mi mi mi 11111111 mi mi 1111 OOOO OOOO OOOO OOOO oooo OOOO OOOO oooo -c B- > <K X tZ* aJ <A a -Q< * " s1 aa oa >E 8 .s sail 2g=l SlSs iiii sas? ssss ssss ss?s = 222 2222 2222 SgSS SSSS SKSK SSgg g:5gg sill Ills =sii isli ssgg ssss gsss gggs """" = =22 222= =222 Ills llll illg IISS Sail sS5l ISss llll oooo oooo =- = - 22222 2222 2222 2222 2222 S310- slsl llll 33*3 333 Ills Slsl 2222 2222 2222 S2S2 22=2 2223 22=2 2222 ! 5=SS ss?s ssgK SS|| 2SS? ss=s g|=a IllsIlls sls= =ggs ills llll =is slsl 2222 2222 2222 2222 2222 2222 2222 2222 ISIS Iiii ISss gill Ills ggs? ssss ssss H u m id ity R atio | W t x 10* sa =< *as* - SSSS S?=S 555? gsss ssss gggs ssss ssss T a b l e 2. T h er m o d yn am ic Properties o r MOIST Air * (Standard A tm ospheric Pressure, 29.921 i n . H o) (Continued) Vap. Press In. H g Pi 36 CHAPTER 3 ' 1954 Guide 03 S3 Sfa < &.H = RSCSS SS882- SSS5SSS SSS3S SSSSS SSSSo ... H < - & Q &5L a ' a5w a a wm z o O >A, Is! i s mu Bill mm ?w mm mm mm oooee deodo --^ --~ -- --ee* mm mu 11111 tim ami issii mu 552SS 22222 Soooo SSSSS gSSSS SSSSS S gS3S S2SSS 8SSS3 S23SE SSS38 3S38S 8S2KS "s > 03 O a OJ . | 03 a o< 0 H ffl mil Hill Illii iii Iilil lllll 1111s odddo oddoo ooooo oood ooooo oooOo ooooo Hill Hill Hill IIllHlii Hi? His 25SSo 33333 33333 ooooo 0=000 ooooo ooooo Siiii liil liil Hill 1111 liiil ii? 23333 33333 33333 333oo ooooo ooooo ooooo 03 c2 d <Q 5B * ICQ > 3 -? A 5 3 8 | 2 d S >e 5s s S 4 s 3 a a H H. s a os 2K" 3 gJ 3w H feH'* SSSRS 33888 SKSS8 lgS5S SS8SS5 35SS3 SSS8S SSSS3 sssss: SKS'SS sssss SSSSS essss PERES 1 SSSSSS 3SS3S SSS25 SSgS SftS8S "SSSS ESSSn S222S SSS8S3 SS8S8 SSSSS 28888 2583? 58S3S iiisg siisi ssssMsssa iiiis ssiss issi sddss S222S S5Sc3c3 SSS38S SSSSS iggis iilil -sisis isss 11111 iiise issss " 2S2SS SSS-S 25:2-- 35338 ! 53333 33333 ISSgg iilil iliiS ddddd ddddd ddddd OOOOO ooooo ooooo <=>-- -- 33335 Slsls 33333 35333 lilii iliii S3S5S 22222 22222 22222 22222 22222 22222 22222 mmiiggi Bliss mu igm ??? SESKR RRESS SS88S SS8S8 gSSSS SSSSg oSSSS 1 Thermodynamics 37 T a b l e 2, T h e r m o d y n a m ic P r o p e r t ie s o f M o is t A i r * (S t a n d a r d A t m o s p h e r ic P r e s s u r e , 29.921 i n . H g) (Concluded) T a b l e 2. T h e r m o d y n a m ic P r o p e r t ie s o f M o is t A i r * (S t a n d a r d A t m o s p h e r ic P r e s s u r e , 29.921 i n . H o) (Continued) 38 CHAPTER 3 1954 Guide Thermodynamics 39 t bs e.^ <s Xfc. friH . SSBSS =sgs Sl"i 1=222 22222I 15.294 I8 S 16.340 16.702 17.071 17.446 17.828 18.217 18.614 19.017 19.427 19.845 18:81 21.145 22:880 22.614 22.987 23.468 Condensed Water 13.675 13.987 i t1i4.e3l0i4 ! >v K . sS ' B o* >2 CKJl--. i c2^* ?? ? si siss ship 00000 00000 00000 00000 000000 E nthalpy B tu/Lb Aw ggsss 0000S ggggg SSSSg ggH2=2 3 22222 22222 .22222' 22222. sSIMSS iSSSS sssss gail S3S1S IIS11I t '< ^ -- > e CINNNN K O sS !!!!!CC tix. 3 !!!!! iiiP =111 si=s a. a a. . H CQ ill! IIIII lii I iffill OOOOO OOOOO OOOOO OOOOO OOOOOO e ilill iliii hm Hill I1IIII *< * >* < *1- B -c2 S6S55 Hill 1|||| ism s|l|l 7, J H <it 2115 isSss igggl 5SS3I aSSSSS 33355 35522 22233 33553 553555 ' 5IH11 sssgs iggKi mis siiiss K SggSS SgSgg S5g?33 233SS S8SS2K DS 05 sins iiiie isssi si ssssgi 1 J 2S22g SSS35S SSSSSS Ek - 03 9 W illls SSBII Sgigl gfsf -1535SS ] 5 22222 22222 22222 22222 222222 ,s H u m id it y Ratio w. ilill iilii Illls IISS5 llsssl J OOOOO OOOOO OOOO-- > K eu _ s< sSSC RSKKg gSggS ggggg =22 SS&SSg-j 40 CHAPTER 3 1954 Guide * g3S3 SSB B5SI P!! !!fT THT Wf8? i i ii i i ii i i i i i iiiiiiiiii iiif iiii iiii if iiii> ? CASaMo Oe<9> nW CQeOCQCO. C4C4C4C4 ii C4C4C4C4 0OC4C4 mnn i a m in? wi h m> e*' oSa -ow nncon eonnn commw Mne) nnnm monn III! IIII IIII IIII 1111 IIII H||| mi iiii iiii iiii iiii iiii iiii iiii an SSSg SSSS 85$ SSSS KS2g SSgg SSSS gSSS llil iill IIII' Iiii iiii iiii gill iiii T a b l e 3. T h e r m o d y n a m ic P roi SSgS SS332 SSSS SSSS SSSS SSSS S33S 5S2S Wa>*3c Iiii iiii iiii iiii iiii iiii iiii iiii SS3r= SSSS 32S2 aSSS'SSSS SKSS 285fe 383S 3 IIII ISS3 SSSS 38S8 S5EE SSSS MM MM M M M M MM MM Mil MM. Of 2 ssss ssl- 33SS Sgsl S||| j|| |||l iss= ssss 22"~ *""" oC?O --dd .-.-S- saw as3 3331 ssis BII ||g I|p isss ssss S2 ~~~~ '--= sf?s gggg Kggg gggg EBBs gggg ssss sSSs SSSS 3333 S3S3 3333 3333 SSSS 3333 3333 0090 oooo oooo oood OOOO 0 00*0 00 0*0* IS3I 1111 Isil IlsS SSSS .oo ooo "."22 2225 3333 3333 333S SSSC S9S5 isife IlsS x p5 III ill ill! KM Mil 58= 8113 III SSSS SSSS 22 SSSS SSSS SSSS SSSS sss I II I IIII IIII I Thermodynamics SSSS 3g22 MM MM mm M7M77 ?m? TTTT w m m w hr|g'0gIQ *C COCOCO _S_2JSS OWK 73*20__20__0__1_-____o-_a--o- _ _ ' w N(MC ANNA oi C9 C e W 0C*C4C4 MWNiN c* ca n cs fill nnnn fill c4cetc fill c4e4e4c4 ge*igeiIOIN Iiii NNNN IIII NNNN IIII; IIII NNNN NNNM i| m S1 ills sillS33-3 sill -swl!;........................ fff? ???? ???? ???? ???? ???? ???? Hu i s :iil 000 8g*sss OOOO mssss OOOO ssbl1s11s1 i*.i*i**i. SSSS SSSS SSSS SSSS SSSS 3222 SSSS-ssaa iiii Iiii iiii iiii iiii iiii iiii i ^'r^_^2P5Po 2StS AIsCOsN sN oesdS-O^sa- lYca}is>d^l ssss SRSS ssss SSSS s'gg'g SSSS.ggss ggg'g 3333 m. 1 u . TTTT TTTT TTTT TTTT TTTT TTTT SI 3 5eeoea?S t-03 40 -^~2 t--r TTt <<>3Ot*S CIC44gCC44CCp940A44 sSSI MONN Ises ^ g|g ^* s=3| - 2SS5 lx SSSS KSSfc ssqs n. o *0 *o w^a>d cdedcded II!I ?!!!!!!! EM SSSS ggg? 3333 3o33 OOOO OOOO 5SSSSSSS SSSS SSSS SSSS SSSS 33333333 SSSS SSSS SSSS SSSS OOOOOOOO OOOO oooo oooo OOOO L sig t'-r^QO oooo 8ggs --C^CO'V* "4^^^ ps<i=s= SSII ---------------- pig wccc |si Ncsnoe SSfK cdcdcd^ |gss I* 4 ft. !!!!!!!!! !!!| fpivN00CeBoaOt OOOO OOOO OOOO OO* I "--A &,(H" SSSS IIII g2S 1111 SSSS 1111 21215T2T ?1<1*1-1> 1>1-1 1 42 CHAPTER 3 1954 Guide S '-""2 =222 22=2 2S5SS 8SBS KSSSS S3 k Sat. V apor .. . IllHIlI 1111 III! ill 111 1 i 1 mmS 1 . u 'w 1111 Jill 1111 ilii III | I MM MM MB JIM IMS MSI 81 1 r?TT ???? TT T?5?? r?TT TTT? ?? * i 2Sgg.SSSS 22SS SSS2 SSSS S3SS 22.2 liii ilii ilii liii iig ini i Sat. V apor Sat. S olid 1 E nthalpy, Btu peb lb SS22 SSSB g33S SS52 ,2ggg S2g Sg 2 sill liii Ilii liii Ills ills 11 !. S22S 2SRS iiii sags 1 1 II 1 1 1 1 SSSS SSKS ssss sss? 111 111 1 1 88SSS SSgS 22 2332 1111 11 11 3? g 33 II fill nil 1111 1111 Ills III! II I Sat. Vapor ' Sat. Solid v* Aj i. ' Sp e c if ic V o l u m e , c u ft p e b lb 0.01903 , 1 0.01748 o'.oiTM 1 0.01748 0.01744 i 0.01744 1 0.01744 0.01744 O.OI743 0.01743 1 0.01744 1 j 0.01744 h a liii mi nn 1111 ills ini n I 0.01747 , 0.01747. 0.01748 0.01746 0.01747 0.01747 , 0.01745 0.01745 0.01745 0.01748 0.01744 0.01745 0.01745 0.01745 i. i i j 1 , In. H * Mil 1111 1111 III? 588! III! 88 1 dodo oooo oooo oooo oooo oooo oo d Is a mi mi sisi mi ms mi u i 1 oooo oooo oooo oddd dodo oooo do o -""2 =222 22=2 2gS8 SSSS KSSgg 5S fS Thermodynamics S"S~ -.go- ssssg fegsss 43 S!S! IB!!i li I!!!1 ill i t* | SI! 11! ill ill II! 11111 .i I. Hill Hill iilll III11 Hill IIIII ^ ooooo d d o ooooo Good d o o' d o' oooo I- SSS3S Sgg= 3S3SS 22SS3 SKSSS sssss >* iiiii liiii iiiii iiiii iiiii iiiii " OOOOO ggfJSg miln220 OOOOC OOOOO A SSSgg Sgggg SSS53S gg--- iiiii Iiiii 5 * o 30 ooooo ooooo 22 ooooo OOOOO o Iiiii fill! IIIII OOOOO OOOOO d 22 S*^*^* ooooo 0*0 ooo ooooc &g SSJSBS KBSgs M Sat. L iq u id W 0.05937 0.06129 0.06320 0.06610 0.06700 0.06890 0.07080 1 1.0990 0.07269 0.07468 0.07646 0.07834 0.0*022 0.08209 0.08396 0.08682 CHAPTER 3 .1954 Guide 3l gssss S? p<bH ,e 1 >3"3 GQ 2.0878 2.0848 2.0818. 2.0787 2.0757 So oSoSosso c^e-teacec-* 0"f'0S'5SS.S e^c4C4C4e Siisi OOOOO cJciwcioj SSSrSoo ooooo eaNN 2S Soooo eaC4C4C*N 1.9845 1.9893 1.0941 2.0030 2.0284 2.0235 2.0186 2.0136 2.0087 gfgli S5oso) a Thermodynamics 45 T a b l e 3. T h e r m o d y n a m ic Pr o per ties of W a t e r a t Sa t u r a t io n * (Continued) m sssss sssss sssss 22222 SS-SS SSSSS 3 a ** Hill Hill fill! Hill Hill Hill a I ---- -- -- S 8I d Is* iliil Hill Hill IlliS Hill IHII I ."2 11111 1111111111 111111111 III? 1 & SRSSg SSSSS SSSg R23SS SSSSS S3SSSS s ** Hill Hill Hill Hill Hiss HHI 1 8 1 SS22SS 5SSS5 SSSSS SSSSS SSSSS SSSSS Is w inii iiiii iiiii iiiii iiii iiiii i 'O 'I sssss sssss sssss ggggs gssss sssss 8ZS25 SSSSS SltKPIi SRSPS sssss sssss 1 s 8 E >^ e* sssss 3355S sssss.-sssss SS1S3 8S3SS sssss sssss sssss ifsis 'SUSS ssllS 1 E !8 > If w SSSSS -S353S sssss iiiii sssss MU sssss IlSIS sssss 3S8S8 sssss 3SS3S 8:${gii 0.01614 0,01614 0.01614 0.01614 0.01615 0.01815 8S 0.01818 8:818? 0.01817 0.01618 0.01618 0.01618 0.01619 0.01819 0.01611 0.01611 0.01611 0.01612 0.01612 I 3 ft 3 1 i ! 1 w%e IIIII. IIIII IHII IIIII IIIII IIIII *-** -- cP4C4e*e c> o esi e co ' Ja c Bill 11111 flljg ISW1 H 111? G'Qv J II- sssss sssss ssgss ggggs' sssss 5ss5 Compiled by John A. Goff and S.'.Gratch. 48 CHAPTER 3 1954 Guide T a b l e 3. T h e r m o d y n a m ic P r o p e r tie s of Wa t e r a t Sa t u r a t io n * (Concluded) Sat. Liquid Vi Compiled byJohnA. QoB and 8. Cratch* 0 fsS<SH&- 'SSSSS B2IS2 2S22 SSSIS sills ssssss f 'o waoA >9 11111 mu mm mis mu imii CjsD CAPBaHQ< . aa>at &M# mil mu 11111 mu mil mm > -aHoaz a h OinOOnOO mOOOOO mOOOOO iOiOiOsOOi sOOiOiOiOi 11o1o1o1o1o riS ! M883 ==SS3 BSSSS SSSS2 SSSgg SSS3SSS Baj 1 nisi mss s==s= uni mu mm ta0fAo<s aA>5 K2SS8 SSSSS ESSSS SSSSS 3S2SS SSSSS2 8SSSS liill 88381 IfessS ISS .gggggg a*5 32*c3*f 5 ggggs SS0S0 SSSSS SS222 2222= =222=2 sssss siggs.|ssss ggsis sSSg5 = ma >B3 A*a e oA CD 2383* 55SS2-SS883 SSiiSj 82333 133833 25235 8SSSS 83S3SS SSSgg SSSSKS pp >HapO>3 A a 38833 38883 SSSI3 33381.3633s' 381382 . 25235 ssj'ess SSKSS .8SSSS SSS3SS sassss 111*110c0u 1OO1O1O1O1IOIOIOHOO MOOOiOlOl SOOOiOlOl OOOOO 1OO1O1OIOSOI. raAP OBh . 8 >a-* ISsss 83883 1S22S 13333.33318 S833S3 222=2 22222 2SS3S S5SSS3 SSSSS SRSSSS f -oB0< ' . aH m& JO IIIII liill ii8S 8888* ^ *33333 *"' "="222 3=22= 22222 222=2= g-^ f3eHf*e* gssss SSSSS 222 Sails 88388 ISISSS Thermodynamics 49 ^.ms?TMmPropertTMbp H. Keenan and F. G. Keyes 50 CHAPTER 3 1954 Guide veniently 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 v, enthalpy k, and entropy s, of moist air per pound, of dry air at any de gree of saturation p may be computed from the simple relations: - !)=. + A h= S =5a "f" (27) (28) (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. 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 precision for most engineer ing design problems. Above 150 F, when greater precision than 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 which is defined as ' n(l -- m)A 1 + aWpi (30) where a 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 values of the coefficient A for several higher temperatures, the value of u at which the correction term v attains its maximum value, and the maximum value of v term there attained. . The correction term for the enthalpy is - _ mU - e)B 1 + aWin (31) Table 5. Coefficients 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, Am. Maximum Value of Correction Defined by Equation 33. Degree of Saturation at Which This Maximum Occurs, Am. 0Standard Atmospheric Pressure) t (F) (ft*A/lba) B (Btu/lb*) (Btcu/F/ lba) 96 0.0018 112 0.0042 12S j 0.0096 144 0.0215 160 0.0487 176 ! 0.1169 192 j 0.3363 0.0268 0.00004 0.0650 0.00009 0.1439 0.00020 0.3149 0.00042 0.6969 0.00091 1.636 0.00207 4.608 j0.00567 (/<tim/labxa) 0.0004 0.0010 0.0022 0.0047 0.0099 0.0207 0.0451 (B&tutn/lbx a) (Btu/F/ lb*) 0.0069 0.00001 0.0155 0.00002 0.0332 0.00005 0.0693 0.00009 0.1418 0.00019 0.2903 0.00037 0.6180 j0.00076 Mm 0.4925 0.4878 0.4805 0.4691 0.4511 0.4213 0.3662 (Btmtua/xF/ lb*) 0.0015 0.0025 0.0040 0.0065 0.0106 0.0179 0.0333 Mm 0.3650 0.3632 0.3602 0.3557 0.3485 0.3363 0.3129 Th ermodynamics 51 Table 5 gives the values of the coefficient B and maximum values of h, the maximum values occurring at the same degree of saturation as v. Corrections for the entropy consist of two terms: s which is defined as - = a(1 - h)C .. 1.+aW& (32) and i, the so-called mixing entropy, which contributes the larger part of the error. The mixing entropy is defined as S = 0.1579 [(1 + uaW,) logl0(l + paW, -- paWJogm (ji) - i(l -f aW,) logio(l 4- aW,] (33) Table 5 lists the values of the coefficient C, the maximum values of s and and the values of p at which they occur. The maximum s occurs at the same degree of saturation as the maximum values of v and 7t. THE ASHVE PSYCHROMETRIC CHART ' A psychrometric chart is a graphical representation of the thenno- dynamic properties of moist air. To be of real value in the solution of engineering problems, it must have distinctive 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 psychrometric chart. This was initially done by Mollier in 1923,''8 and is the arrangement followed in the chart included with The Guide. The A.S.H.V.E. Psychrometric 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 Fapigp.r3o.ximately 40 deg with the humidity ratio axis. This is shown in For practical use, the inclusion of dry-bulb and wet-bulb temperatures, volumes, and indices of the condition of the air in relation to saturation, is necessary for locating and describing states on the chart. The arrange- 52 CHAPTER 3 1954 Guide meat of the families of curves of constant dry-bulb temperature, wet-bulb temperature, volume, relative humidity and degree of saturation, are shown in Fig. 4. Mass and energy balances deal only with net changes between definite states; the detailed history of a change is not involved. A chart used to facilitate such calculations must primarily aid in clearly establishing states. Lines drawn on the chart to connect different states need have Thermodynamics oV, ,, T " *EM SONOOd-OUVS A-LIOIWDH a8 S8- S Kd .S 9S S S- S- -9 29 S? '52 255S! 5- 3o 8* 2 2i- 90* 53 CA) (B1 ORY-BULB TEMPERATURE (0) Fiq. 4. A.S.H.V.E.Arrangement ok Families op Curves on PSTCHROMETBIC Chart no other significance than being loci lines, that is, lines which contain the two terminal points of a change according to the particular overall con ditions imposed. Loci lines are commonly called condition lines-for the processes concerned. On the A.S.H.V.E. chart a condition line is char acterized by the ratio (hj -- hi)/(Wi -- Wi). An abridgment of the A.S.H.V.E. Psychrometric Chart appears in Fig. '5. A large size (24 x 32) chart will be found on the inside of the back cover. ; The chart is drawn for standard atmospheric pressure. Steady .flow changes .commonly involve pressure drops with the flow, but so. long as these ,pressure drops remain a small fraction of the barometric pressure, no appreciable errors need arise from using a constant pressure chart. For many design problems, the use of the standard pressure chart will not incur any undue error up to about 2000 ft above sea level. v The;region above- the saturation curve is a two-phase region giving equilibrium' states for water in. both the liquid and vapor phases. The ordinate of a point in this region is. the weight of water in both phases per pound of dry air in the vapor phase, neglecting any dissolved air P~##S8 Fiq. 5. A.S.H.V.E.Abridgment of Pstchrometbic Chart in the condensed phase. The ordinate at the saturation curve, or the point at which the break in the isotherm through the point in question occurs, is the weight of 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 isothermal threephase zone, and separates the liquid-vapor zone from the solid-vapor zone. The temperature is 32 F throughout the shaded area. 54 CHAPTER 3 1954 Guide It is possible to obtain two values for the wet-bulb temperature 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 wet-bulb 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 oh the bulb of the thermometer. After reaching 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 than 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 subxooled water, the chart, below 32 F, has been drawn for the equilibrium condition, that is, the values plotted on the A.S.H.V.E. chart are for the condition where the minimum temperature is reached with ice on the bulb of the thermometer. USE OF TABLE 2 AND THE A.SJS.V.E. PSYCHROMETRIC CHART The use of Table 2 and the A.S.H.V.E. 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 1: 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 A,, = 24.47 Btu per lb of dry air. Then A at the specified conditions is 19.221 + 0.40(24.47) = 29.01 Btu per lb of dry air. SoliUion b: From the A.S.H.V.E. Chart. Follow the 80 F dry-bulb line vertically until it intersects the 0.40 degree of saturation 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 S: Determine the thermodynamic wet-bulb temperature of moist air at the conditions of Example 1. Solution a: From the data of Table 2. Applying Equation 8, At = 29.01 Btu per lb of dry air (Example 1). As a first approximation this is A* the enthalpy at satura tion at the thermodynamic wet-bulb temperature which is, therefore, approximately 63.5 F. IF* at 63.5 F is 12.57 X 10~' lb of water vapor per lb of dry air, and W, 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 approximation, A* = 29.01 + (0.01257 -- 0.00893) (31.58) = 29.12 Btu per lb of dry air. Interpola tion in Table 2 gives as the final answer <* = 63.64 F. Solution b: From the A.S.H.V.E. Chart. At the intersection of the 80 F drybulb temperature line and the 0.40 degree of saturation line, read the thermodynamic wet-bulb temperature. Heating of Moist Air at Constant Pressure Without Addition of Moisture Example S: Air initially at 20 F, 0.80 degree of saturation, is heated to 120 F. Find the quantity of heat required to process 20,000 cfm of heated air. The process is diagrammatically illustrated in Fig. 6. The energy equation for the process is Ghi 4 iff, -- Gha or iff, = G(A. -- AO Thermodynamics 5i . .o, Fig. 6. Illustration of Process of Example 3 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 ib of water vapor per ]b 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(80.70) = 30.757 Btu per lb of dry air; the final volume is 14.611 4- 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 required is . ,ff, = (20,000/14.651) X 24.111 = 32,914 Btu per min. Solution b: From the A.S.H.V.E. Chart. The process is represented by the horizontal line 1-2, Fig. 7. The initial enthalpy, at 20 F dry-bulb temperature and 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, -- Ai)/(tF, -- (Fi) = o. The horizontal line 1-2, Fig. 7, then represents the condition line for the process, and the final state of the moist air most 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 the 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. Substituting these values in the energy equation, iff, - (20,000/14.65) X (30.8 - 6.65) = 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 * Wt = constant until the saturation line is intersected. The Fig. 7. Solution 3of Example on A.S.H.V.E. Psychrometric Chart 56 CHAPTER 3 1954. Guide temperature at this point of intersection is by definition the dew-point temperature for state 1. Further cooling through successive equilibrium states is accompanied by condensa tion. The succession of states for the total system, moist,air and liquid water, is represented by a continuation of the W = Wi line into the liquid vapor region. (Tem peratures below 32 F would involve the solid-vapor region). Consider that' the final temperature is Is. The final enthalpy is then hi; the liquid water formed is (trt -- TFi), 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 VF,; and this final moist air has dew-point, wet-bulb and dry-bulb temperatures all equal to t. Example 4-" How much heat 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) = 0.01837 lb Of water vapor per lb of dry air; the initial enthalpy is 22.827 + 0.50(40.49) = 43.072 Btu per Id of dry air; the humidity ratio at saturation at the Wi Flo. 8. Cooling op Aib at Constant Pkessuhe Shown on A.S.H.V.E. PSYCHBOMETRIC CHART 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 dry air. Fig. 9 illustrates the process diagrammatically. The energy equation for the process is Ghi = Ghi + G(Wt - Wi)h,i + 1?, or ,g, = G[h, - ht - (Wi - W,)h,,] = 2-20,0--00 x (43.072 - 34.09 - 0.00255 X 38.07) 14.391 = 12,350 Btu per min. Solution b: From the A.S.H.V.E. Chart. Two methods may be used to solve the f>erfot bolfemthebysautsueraotfiothnelinpesy(cFhigro.m8)e.tricFrcohmarpt.oinTth1edsriamwpalehr oisritzoonustael the region to the line on the chart until it intersects the constant temperature line in the liquid-vapor region corre sponding to the final temperature, 70 F. This is shown as point 2 on the diagram. Then, 1 i? = G(hi -- hi) The initial enthalpy is 43 Btu per lb of dry air; the initial specific volume is 14.4 Thermodynamics cu ft perlb of dry air; and the final enthalpy is 34:2 Btu per lb of dry air. tion of the problem is : 57 The solu 20,000 , i?i = 14.4 - X (43 -- 34.2) . 12,200 Btu per min. . . : The other method is to use an energy balance, ,q, = G[h, - h, - A(JFi -- TFj)] 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 heat to be removed is " 20,000 i?i 14.4 X (43 34.1 - 0.0025 X 38.07) -- 12,130 Btu'per min. IS 7^7777srr. .. 51 Jy Fig. 9. Illustration op Process op Example 4 Adiabatic Mixing of Two.Steady Flow Air Streams at Constant Pressure The process is diagrammed in Fig. 10. By applying the principles of the con servation of mass and energy, three equations may be written: Mass balance for the dry air, + Gt = Gi Energy balance for the process, Gihi -f- GJii = Gih2 Mass balance for the water vapor, GxW, + GtWi = GtW, . Eliminating Gi and combining the three equations yield the equation, hjzh = = ?! . hi - A, Wi-Wi Gt . (34) is tEoxbaemmpiUxeSd; aOdiuatbsaidtiecaalilryawt i0thFrdecryir-cbuulalbtetedminpseidraetaurireaatn7d00F.8d0rdye-gbruelebotef msapteurraattuioren 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 saturation in the resulting mixture. h, uSmoidluittiyonraati:o FWrot mantdhethdeaetantohfaTlpaybAle. 2o.f tThheereosnulyltinugnkmnoixwtunrep.ropTehretisees maraey,thbee determined from Equation 34. Thus, 58 CHAPTER 3 1954 Guide . 20.270 - A, _ 0.003164 - W, 1 , A, - 0.668 ~~ IV, - 0.000630 _ 4 from which A, = 16.350 and W, = 0.002657. The eDthalpy_of the final mixture may also be expressed by Equation 28: , Aj = A, + pA*, Since /i by definition is IV,/IV,, Equation 28 may be rewritten as 16.350 = A, + (0.002657/IV.) X A,, At 56 E the right side of the equation is 16.332, and at 57 F it is 16.582. Interpola tion gives as the final dry-bulb temperature of the mixture' 56.07 F. At this tem perature the humidity ratio at saturation is 0.00960 lb of water vapor per lb of dry air. Therefore, the final degree of saturation is M = 0.002657/0.00960 = 0.277 Solution b. From the A.S.H.V.E. Chart. Equation 34 indicates that the state point of the resulting mixture lies on a straight line connecting the state points of Fig io. ' Illustration of Mixing of Two Steady Flow Streams at Constant Pressure . the two streams being mixed, and divides this line into two segments whose respec tive lengths are inversely proportional to the rates of dry air flow in the Correspond ing streams. This is illustrated in Fig. 11. Points 1 and 2 are located and connected by a straight line. The state of the final mixture is set so that Gj ftj-i _ 1 (i? Dj_i 4 Scaling 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 Gi(lV, -- Wt) and the moisture having the enthalpy A Btu per pound of moisture. An energy balance yields . .. Giht + GxiWt - Wi)K == Oiht (35) Example 6: Liquid water chilled to 40 F is injected into an air stream initially at Thermodynamics 59 Fro.'11. 5 A.S.H.V.E.Solution of Example on Psychrometric Chart 95 F dry-bulb temperature and 80 F thermodynamic wet-bulb temperature. At what temperature will saturation be reached ? How much water must be evaporated to reach saturation? Solution a: From the data of Table 2. The solution of Equation 35 for At yields A, = A, + (W, - IV,)A. The initial enthalpy of the moist air A, must be found from Equation 8, ` A, = A* - (IV* - IV,)A,,* 22.827 4- p40.49 = 43.69 - (0.02233 - 0.03673p) (48.05) from which M = 0.511. Hence, hi = 22.827 0.511(40.49) = 43.52 Btu per lb of dry air and IV, = 0.03673(0.511) = 0.01877 lb per ib of dry air. The solution of Equation 35 is A, = 43.52 + (IV, - 0.01877) (8.09) By trial and error, this equation wili be satisfied at the temperature 79.87 F. At this temperature the humidity ratio IV, is 0.02223. The weight of water evaporated is therefore 0.02223 -- 0.01877 = 0.00346 lb per Ib of dry air. Fiq. 12. G(Wj -W,) AT ENTHALPY h. Illustration of Addition of Moisture to an Adiabatic Stream 60 CHAPTER 3 1954 Guide - Solution b: From the A.S.H.V.E. Chart. Solution of Equation 35 for the ratio (ft, - hi)/{Wt - IFi) yields hi -- hi if, - w>" (36) The slope of the condition line is therefore determined by the enthalpy of the water which is supplied. This slope is established on the chart by connecting the center of the protractor on the psychrometrie chart with the value of A. on the pro tractor. 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 require the final point to lie on the saturation line, the intersection 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 unsaturated condition to a saturated one witb- Fio 13. 6 A.S.H.V.E.Solution of Example on Psychbometric ' Chart p out the addition or removal of heat. According to this definition, the addition of moisture to an adiabatic stream may become an adiabatic saturation process. Ex ample 6 is an illustration. A type of adiabatic saturation of further practical interest is the use of continually recirculated spray water in a saturating air washer. Here the spray water will ultimately come to the same temperature as the saturated leaving air; this tempera ture is, by definition, the thermodynamic wet-bulb temperature. 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 psychrometrie ehart as sketched in Fig. 14. Example 7: Moist air at 75 F dry-bulb temperature and 0.60 degree of saturation, is saturated adiabatically with recirculating spray water. Find the amount of water added and the change in enthalpy. Solution a: From the data of Table 2. As previously stated, the final tempera ture of the mixture will be the thermodynamic wet-bulb temperature at the initial state. This must first be determined by the method of Example B, 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) == Q.Q11&); t{?e initial enthalpy is 0.60(20,59) -f- 18.018 = 30.372. The weight of water Thermodynamics 61 14.Fig. Moisture Added and Temperature Change is therefore 0.01350 change is 30.45 -- 30.372 =* - 0.01129 - 0.00221 lb per 0.078 Btu per lb of dry air. lb of dry air; the enthalpy Solution b: From the A.S.H.V.E. Chart. Since the initial and final states have the same thermodynamic wet-bulb temperature, the results may be read directly from the chart. Addition of Heat and Water Vapor to an Air Stream in Steady Flow wheFrieg. 15 is a schematic representation of a system operating at constant pressure, Gt is the rate of flow of dry air, pounds per minute. G. is the rate of evaporation of the water, pounds per minute. ft. 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 Gifti -f- Q + G.A. = Gifts A mass balance gives (37) or G, + GxWi + G.= Gi + GilFs G,lFi + G. = G,fPs (38) Flo. 15. Illustration of Ald,tion of Heat, and ;WaTe,e Vapor to an Air Stream in Steady Flow 62 CHAPTER 3 Combining equations 37 and 38 and solving for the ratio (h, - 1954 Guide " w>)' Wi - Wi G, (39) Example 8: Moist air at 20 F dry-bulb temperature and 0.80 degree of saturation is heated and humidified until it is at 120 F dry-bulb temperature and 71.5 F thermo dynamic wet-bulb temperature. Water at 55 F is supplied. If the air 0ow rate is 20,000 cfm at the initial conditions, how much heat is required? . 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 + 0.80(2.302) = 6.6456; the initial specific volume is 12.084 + 0.80(0.042) = 12.118. The degree of saturation at the final state may be determined from Equation 8 which may be rewritten as A.: + mA.,, + A.*(W* - uJT.0 = A* Fig. 16. 8 A.S.H.V.E.Solution of Example on Psychbometric Chart The values of these properties are: A* = 35.39; Wm = 0.01668; Aw* = 39.61; A,,i =* 90.70; W,, = 0.08149; A., = 28.84. Making the proper substitutions and solving for degree of saturation, .= 0.0681. The final 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. Gw = 2-0L0--00 (0.005549 - 0.00172) ' 12.12 = 6.32 lb per min. The heat supplied is obtained from Equation 37. Q = G,(A, _ A,) - GwA, = 2-0r0--00 (35.02 - 6.65) - 6.32(28.08) . 12.12 : . = ,46,667 Btu per min. Solution hi From th'e--A\S.H.V.l3. Chart. '-Locate-the initial and final states on 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 (At -- Ai)/(W -- Wi) as 7500 from Thermodynamics 63 the protractor on the chart (Fig. 16). From Equation 39 , hz -- hi _ Q_ w. Wi~ G,,+h' -- 7500 ?hStateItfisWater BUPPly WSS determined in Solution a, but will be found from the Gy = (0.0055 - 0.0017) = 6.28 lb per min Q = <?w(7500 - ftw) = 6.28(7500 - 23) " 46,900 Btu per min. . Table 6. Pressure and Temperature for Altitudes in U. S. Standard Atmosphere . Altitude Feet Z - 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 Pressure In. of Hg P 31.02 30.47 29.921 29.38 28.86 24.89 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 U. S. STANDARD ATMOSPHERE The definition of the U. S. Standard Atmosphere is important to the air conditioning engineer as an essential standard of reference. The basic assumptions in defining the Standard Atmosphere are: the1.isTohtheerermisalaaltimneoasrphdeercereaaste35in,33te2mftp.eraTthuures, T with . altitude up to the limit of T = T. - 0.003566 Z 2. The air is dry. 3. Air is a perfect gas obeying the laws of Charles and Boyle: (40) PV = RT - . _________________________________ nivu me ataiiumu VttiUC. 5. The temperature of the isothermal atmosphere is --66 F. Standard values at sea level, which are part of the definition of the Standard Atmosphere, are: Pressure Temperature 29.921 in. Hg 59 F 64 CHAPTER 3 1954 Guide Absolute Temperature Gravity Density 518.4 F Abs - . 32.1740 ft per (sec) (sec) 0.07651 lb per cu ft i .Values of pressure and temperature are listed in Table 6 for altitudes in the standard atmosphere' from --1000 to 50,000 ft above sea leVeh For further explanation, References 9 and 10 should be consulted. LETTER SYMBOLS USED IN CHAPTER 3 ix = degree of saturation (decimal), p = density of fluid, pounds per cubic foot. v = 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 (obtained 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). /. = factor accounting for effect of mixing air and water, dimensionless. G = flow rate of dry air, pounds per hour. Gi = flow rate of dry air, pounds per minute. G -- 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. /i* = specific enthalpy of dry air, Btu per pound. Ku, = h, -- h = 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. . A = enthalpy of saturated water vapor, Btu per pound. A. = enthalpy of moist air at saturation per pound of dry air, Btu per pound of dry air. ft.* = enthalpy-of moist air at saturation at thermodynamic wet-bulb temperature, <* Btu per pound of dry air. ft. = specific enthalpy of condensed water (liquid or solid) at standard pressure, Btu per pound water. , ft.* = specific enthalpy of water as added at the thermodynamic wet-bulb tem perature t', Btu per pound of dry air. ft.i = enthalpy of liquid water, Btu per pound. A.. = enthalpy of solid water, Btu per pound. KE = average kinetic energy, Btu per pound. KE == 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, = mols dry air. h.-= mols of water vapor at saturation, n. = mols of water vapor. P = absolute pressure. P,, = atmospheric pressure, inches Hg. Thermodynamics 65 LETTER SYMBOLS (Continued) P, = standard atmospheric pressure by definition 29.921 in. Hg. P. = saturation pressure of pure water at prevailing temperature. v = total pressure of a mixture of air and water vapor, pounds per square inch or inches Hg.. partial pressure of dry air, pounds per square inch or inches Hg. 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. 9 = ratio of energy added (or removed) to water added (or removed), Btu per pound. Also called specific enthalpy of water added. iQ = energy added between points 1 and 2. . m = heat added between sections 1 and 2, Btu per pound dry air. R - Universal gas constant, 1545 foot-pounds per (Fahrenheit degree) (mol), E. = gas constant for dry air. R, = gas constant for water vapor. S = flow rate of solid water, pounds per hour. . e = entropy of moist air per pound of dry air, Btu per (pound) (Fahrenheit degree). . s = correction to be added1 to entropy of moist air obtained from Table 2. s = additional correction to be added to entropy because of "mixing entropy" (obtained from Table 5). Correction to be added to value of s obtained from Table 2. " specific entropy of dry air, Btu per (pound) (Fahrenheit degree, absolute), 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, absolute). entropy of moist air at saturation per pound of dry air, Btu per (pound of dry air) (Fahrenheit degree, absolute). specific entropy of condensed water (liquid or solid) at standard atmos pheric pressure, Btu per (pound of water) (Fahrenheit degree, absolute), T = absolute temperature, Fahrenheit degrees. To = standard atmospheric temperature, by definition 518.4 F absolute, f = temperature, Fahrenheit degrees. t* = thermodynamic wet-bulb temperature, Fahrenheit degrees, U = internal energy of system. * u = internal energy, V = volume. V = average velocity, feet per minute. v = volume of 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. v. = specific volume of dry air, eubic feet per pound. 66 CHAPTER 3 1954 Guide . LETTER SYMBOLS (Concluded) = vt -- va> 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. vt total volume, cubic feet. W = humidity ratio, of moist air, pounds of water per pound of dry air. W. a = humidity ratio, at saturation, weight of water vapor per pound of dry air, pound per pound. Ws* = humidity ratio corresponding to thermodynamic wet-bulb temperature (*, pounds of water per pound of dry air. w = work done by system. w 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 flow; a = air, w = water, wZ = liquid water, ws = solid water, s = saturation, m = mixture; * indicates that the value is at thermodynamic wet-bulb temperature. REFERENCES 1 The Humidity Ratio of Moist Air at Saturation, by J. A. Goff and S. Gratch (Special Report of University of Pennsylvania Thermodynamic Research Laboratory, March 1948). 1 Standardization of Thermodynamic Properties of Moist Air, by J. A. Goff (A.S.H.V.E. Transactions, Vol. 55, 1949, p. 459). , 8 The Theory of the Psychrometer, by J. H. Arnold (Physicst Vol. 4, 1933). 4 Thermodynamic Properties of Moist Air, by J. A. Goff and S. Gratch (A.S.H.V.E. Transactions, Vol. 53, 1945, p. 125). 6 Low Pressure Properties of Water in the Range --160 to 212 F, by J. A. Goff and S. Gratch (A.S.H.V.E. Transactions, Vol. 52, 1946, p. 95). 1 6 Thermodynamic Properties of Steam, by J. H. Keenan and F. G. Keyes (John Wiley and Sons, Inc., New York, 1936). 7 Ein neues Diagramm fiir Dampfluftgemische, by R. Mollier, (ZVDI, Vol. 67, Sept. 8, 1923, p. 869-872). 8 Das i-x Diagramm fur Dampfluftgemische, by R. Mollier (ZVDI, Vol. 73, July 20, 1929, pp. 1009-1013). 9 National Advisory Committee for Aeronautics, Technical Report No. 218, 1925. 10 National Advisory Committee for Aeronautics, Technical Report No. 538, 1935. CHAPTER 4 FLUID FLOW Theory of Fluid Flow, Pressure Loss in: Circular Pipes, Pressure Loss in Non Circular Pipes; Flow of Compressible Fluids, Ideal Flow Through Nozzle or Orifice; Flow Measurement, Head Meters, Installation of Head Meters, Pitot Tube, Variable Area Flow Meters THE flow of fluids is part of the branch of engineering science known as fluid mechanics, which will be discussed 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 are often involved. Compressible fluids (gases) and incompressible fluids (liquids) vary somewhat in behavior, though in cases where pressure and density changes are small, the gases may be treated as incompressible fluids. 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 V, g V,2 g ------<r Jui + p,, + Jq + -- z, = -- -P Jui + p,v3 4- W 4- -- zt 2Sc 0c 2gc gc (1) where V = velocity in feet per second. g = gravitational acceleration, in feet per (second) (second). go = 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, in Btu per pound of fluid. p = pressure in pounds per square foot. v = specific volume, in cubic feet per pound. W = mechanical work done by the fluid in foot pounds per pound of fluid. . q = heat transferred to the fluid in Btu per pound of fluid flowing, z = elevation above some arbitrary datum, in feet. " Subscript 1 refers to the entrance, subscript 2 to the exit. . Introducing the enthalpy h, which by definition is u + y, Btu per pound of fluid, Equation 1 becomes V,` g VS g + Jh> + Jq + + /*, + W + 2gc 20c 0. .. .* The equivalent differential form for energy Equation 1 is in (2) -- dF! + J du + d(pv) + - dz - J dq + dW = 0 20c 0c 67 (3) 68 CHAPTER 4 1954 Guide /- Replacing v by its equal g/g<# (where p is density in pounds weight per cubic foot) and rearranging, Equation 3 becomes -- dV* + - dp 4- dz + -- [J du 4- v dv -- J dg -f dW] = 0 2g p . g (4) In the case of flow through a pipe, no outside work is performed so that dW. 0. Furthermore, J du + p dv = JT ds = J dg + JT ds' (5) where ds = total change in entropyds' = change in entropy due to internal irreversibility from turbulence and friction. ,. Fluid Flow 69 pipe diameter were the same throughout, the velocity, and consequently the velocity head, would 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 remembered that in it the effects of friction and turbulence are neglected, and that Fig. 1 represents ideal conditions. It should also be noted that, erne must be taken in determining the proper mean density. Accordingly, the Bernoulli equation is applied most conveniently to incompressible fluids for which' density is constant. . Fio. 1. Relation of Vabiotjs Factors in Bernoulli Equation Accordingly, Equation 4 may be written -- dV1 + -- + dz + -- JT ds' = 0* (6) . 2geo . In cases where there is no internal irreversibility, ds' = 0, and Equation 6 may be integrated to give . --F>s H,---P--i----,*- t.i _ = -T- 4,---P--L--- ,\r S. t 2g pm ZQ Pm (7) where p is the proper mean density. This is commonly called the Bernoulli equation, named after the Swiss mathematician and physician who first propounded the theory. ^ is known as the velocity head, ~ is the pressure head, and z is the elevation p. . head, all in feet of the fluid; the total head, ht is the sum of the other three heads. Fig. 1 shows diagrammatically 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 In the analysis of subsequent portion of this chapter the dtotincto^^ and Aside from the dimensional consistency the factor, g/ge, is not in general signifies ' Fig. 2. Relation of Kinematic Viscosity to Temperature of Air Pressure Loss in Circular Pipes The pressure loss in circular pipes is customarily expressed by the formula: flV* h, 2ffd where hi = the Joss in head of the fluid under conditions of flow, in feett 1 = the length of the pipe, in feet. V = the velocity, in feet per second. g = the acceleration due to gravity = 32.174 ft per (second) (second), d = the internal diameter of the pipe, in feet. / = a dimensionless friction coefficient. (8) The formula is generally known by the name of Darcy or Fanning, though it seems to have been originated by d'Aubisson de Voisins in 1834. The factor / is a function of the Reynolds number, ' u (9) 70 CHAPTER 4 1954 Guide where '- . = Reynolds number. p -- the density in pounds per cubic foot. p = the absolute viscosity in pounds per foot-second. Both / and the Reynolds number are dimensionless. . To aid in com puting the Reynolds number, values of the kinematic viscosity, are p ; 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: Fluid Flow 71 unstable region where the flow changes from laminar to turbulent, or vice versa. The actual value is impossible of prediction for any condi tions of flow, though in general it may be said that the prevailing type of flow persists into the unstable region; however, once the 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 Viscosity to Temperature of Water 64 1 ~ N*,, GO) With laminar flow, the velocity profile is a parabola, having the formula: V = - /.') (11) where r = the radius of the pipe in feet. L = distance perpendicularly from the axis of the pipe, in 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, there is an i Superior numbers refer to the references at the end of chapter. Fig. 4. Relation Between Friction Factor and Reynolds Number Note: The straight line at left shows values of Friction Factor for laminar flow. Reprinted by permission from ASM-B Transactions. or glass tubing. The effect of roughness on/, an effect which ia 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 the proper value of e/d, to the pertinent value of VR0> and from this, point proceed horizontally to left margin to find the value of / for use in Equation 8. 72 CHAPTER 4 1954 Guide '' - The curves in Fig. 4 may be approximated very closely by the empirical formula:1 ' r / = .0055 +/(20,000 e- + io`Y'>n (12) Equation 8 is applicable to all liquids, and to gases when the 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 -- pS = JIVS Pi* gd pii (13) which may be arranged to give the loss in pressure, Pi -- Pi = Pi firs g d pint _ (14) r % X 'i f:i p Fig. 5. Comparison of Velocity Profiles for 3 Different Reynolds Numbers but for Same Average Velocity 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 non circular sections, by suitable modification. In the basic formula, Equation 8, the internal diameter d is to be replaced by the hydraulic diameter dB defined by the equation: ' 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 hydraulic diameter will be dH = (4x2)/6 = iy,ft. In the case of a round pipe, . dH 4 X vdV4 xd a (16) In computing the Reynolds number, and from that the friction factor, the hydraulic diameter is hot 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 friction factors, is A'*. = ( + 0.25dH)Fp/(i (17) Fluid Flow 73 1.Table Values of e for Different Kinds of. Pipe. . Typk of Pipe C- " Smooth drawn tubing.......................................................................... Commercial steel or wrought iron /:.............. ......................... Asohalted east-ire*"............................................................................. Wood stave................................. ....................... Concrete................................................................. 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 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. FLOW OF COMPRESSIBLE FLUIDS In the flow of compressible fluids, the large density variations make impracticable the use of 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 internal irreversibility, Equation 6 becomes - dV* -h -- = 0 2g p If, in addition, the flow is adiabatic, pp~* = pu>r* so that Equation 18 becomes 1 2g dV__l + --pi pd>~lpt- = 0 or by integration, (18) (19) (20) 2-g W - VS) + k (21) 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, k, is used extensively in fluid dynamics; values of k for various gases are given in Table 2. Table 2. Ratio of Specific Heat at Constant Pressure to Specific Heat at Constant Volume for Compressible Fluids . Compressible Fluid Helium and other monatomic gases......................................... Air and other diatomic gases....... .................................................. Ammonia and hydrogen sulfide................................................. Carbon dioxide, methane, natural gas, superheated steam, moist steam down to a quality of 97 percent......................... Sulfur dioxide, ethylene, acetylene.......................................... Ratio ** cp/cr 1.66 1.40 1.34 1.28 to 1.32 1.24 to 1.26 74 CHAPTER 4 1954 Guide It is convenient in the analysis of compressible flow to introduce the velocity of propagation of pressure impulses or, more familiarly, the sonic velocity, a. For perfect gases this is given by the equation: o' = kgp/p = kgRT__ (22) Accordingly, Equation 21 may be written KW - VS) + =0 (23) or, by rearrangement, P 1 (24) Pi 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 and 22 it follows that aS = T, = (pA^ as Ti \m) (25) so that ---- (VS - TV) + aS - a,2 = 0 2 (26) ind k- 1 VS aS _ 1 + 2 aS a,8 k -- 1 VS 1 + --rf (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 g 0.1 the flow may be considered to be incompressible. This is generally true in heating and ventilating air ducts. In terms of the Mach number 1 + ---- MS of = Ti = 21 (28) and The quantity, Y1(i+--m' P Pi k--1 , K1 + -Tm*I P = P (29) (30) Fluid Flow 75 is called the stagnation pressure, and gives a measure of pressure energy. For incompressible flow P = p+hpVt P + 9 where (31) <? = ^pV2 2g .. (32) and is the dynamic pressure. A total head tube measures stagnation pres sure directly. From Equation 29 it follows that for frictionless, adiabatic flow . p, - 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 low 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 frictionless and adiabatic. Designating the main stream by station 1, and flow at some measuring restriction by station 2, the flow in pounds per second is w = pubFi = ptAtFi (34) or, in terms of Mach number, . id -- AiMt \/ktypzPr According to Equation 29 k--1 1 + --w from which fc - 1 1 + --"** (35) (36) (37) 1 so that ah/ k- 1 1`+' ---- MS 1 - MS/MS y k - 1 j_\p,/ J (38) If the initial velocity is sufficiently small, Mi will be negligible so that If this is computed and the figures are plotted, the curved line (partly solid and partly broken) of Fig. 6 is found. The maximum value of may be computed by differentiating w with respect to pi and equating the result to zero. This operation produces the formula: - ft ( 2 \JL ft-Vrnr "For air, with k = 1.40, -- = 0.63. Pi Actually, the broken part of the curve is not attained for the flow in the .nozzle. If the ratio of p, to pi is decreased from unity, the mass rate of discharge, as well as the volume, increases from zero to a maximum, as shown by the solid section of the curve in Fig. 6; thereafter, as pi/pi is decreased further, the discharge is constant, as indicated by the horizontal line. The value of pj at the maximum point is called the critical pressure, or p, and it is seen that p0 is approximately 63 percent of pi when air is flowing. ; ? ; v s J Fluid Flow 77 In developing the working equations for orifices and nozzles, it is custom ary. to start with the incompressible form of the flow Equation 38. In tins case both M, and Af, are small quantities, pi = p,, and (p, - ftW EquffisS tST R^tammg 0nl^ firet order ^ follows from so that Mi At Mt A, (44) , . k-1 1+-Z-M,' 1 - Af,yAf,! vi -- (Ai/Ai)! , Vi - (45) where 0 = Ds/A. The quantity 1/VT - 0* is the velocity of approach Fio. 6. Relation or Flow or Gas to Pressure Drop in a Converoino Tube To find the velocity at the critical pressure, it is assumed that the upstream velocity Vi is so small as to be negligible. Using the subscript c to indicate conditions at the critical point, from Equation 20 (41) Pl or "-lAMfeF-1]. " Substituting the critical pressure ratio from Equation 40 it follows that = 1 (43) f | or that the velocity at the throat is equal to the local sonic velocity. IA-*. -Ti <" i 50.02 Oj I * 5aioo, 5r 4-lOJ Qf* Z 5 1C? 2 3 FlG' $003 Of-J 3 D| C--o) AND Flo7 Coefficient for Standard Sharp Edged Orifice (Coefficient shown as a function of Reynolds Number and Ratio, A/A.) Note: From Reference 4. Used by permission. factor as generally used, with 0 being the ratio of the throat or orifice di ameter to the pipe diameter. Since Ap/p2 is small and the mass flow is At to -- \/2gpAp Vl - 0* The volume flow is then Q A` ^ V2gAp/P =. A, ^7= V2A. (46) (47) (48) i I ! 78 CHAPTER 4 1954 Guide 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 pressure drop across a metering orifice, or by the displacement of some device, such as a rotating vane system. The selec tion of the metering system will be determined by the type of fluid, the precision of measurement desired, the cost of equipment and installation, the range of flow quantity, the ease of maintenance, and -the method of observation and recording. 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 Meiers, which may be of gate, tapered tube, or tapered plug types; (3) Force Meiers, which may be of vane, propeUor, or turbine types;' (4) Quantity Meiers, which may be of weighing tank, reciprocating piston, or geared impeller types. Rate meters are generally of the first three groups, although rates are Fluid Flow 79 Fig. 8. Dimensions fob International Standards Association Flow Nozzle Note: From Reference 3. Used by permission of A.S.ME. obtainable from timed observations of quantity meters. Similar quantity measurements can be obtained by suitable integration of rate meter indications. Head Meters . The head meter is of sufficient flexibility so that almost any type of flow measuring problem can be handled. For this reason, standard and refer ence measurements are usually made in this way. With proper care, extreme precision can be obtained. 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 advantage of having a low pressure loss, but requires considerable 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 calibrated individually, or made with extreme care from standard specifica tions, to obtain a good precision of measurement. Standard configurations, for representative orifice plates and flow nozzles, are shown in Figs. 7 and Fig. 10. I'm. li Taps in Smooth Pipe Note: From Fig. 36d of Reference 4. OONTRACTA IaPS, IN SMOOTH PlPE Note: From Table 7 of Reference 2. 80 CHAPTER 4 1954 Guide 8, respectively. Additional specifications are given in References 2, 3, and 4 at end of chapter. The measurement of flow in head meters is dependent upon observations of a static pressure difference between two parts of the system. In gen eral, 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 contracta following an orifice. -In either case, the flow will be given by a suitable modification of Equa tions 47 and 48. Adding a correction term, these become A,C ,--------- w = ^ -- V 2ffpAp (49) Fluid Flow 81 and Q = KA, Vight ( (53) The coefficients K and C will be determined by the area ratio Ai/At, or by the diameter ratio D1/D2 and the Reynolds number. Extensive data are available from various sources.1, * Figs. 9, 10,11, 12 show repre sentative values of K based on IVr,, 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 cases where the tests are run under non-standard Fig. 12. Flow Coefficient fob International Standards Association Flow NNozzle as a Function of Abea Ratio (Dj/Di)! and the Reynolds Number k. Note: From Reference 3. Used by permission of ASMS and AC ,___ _ Q = yfiZTp v2gh` In all cases, A2 refers to the minimum area of the Venturi, nozzle, or orifice. The 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 configuration, as described by the ratio of upstream to minimum area A1/A2, it is often convenient to introduce a combined flow coefficient, K which is C K= Vw (51) so that w <= KA,\/2gpAp (62) Fig. 13. Relation of Expansion Factor, <t>, fob Nozzles to Diameter Ratio and Pressure Loss for Air and Other Diatomic Gases conditions, care must be taken that proper adjustment be made in com puting flow rates. In measuring the flow of compressible, fluids, the approximate Equations 52 and 53 must be corrected for density variations. The need for such correction is evident by comparing Equations 35 and 38 with Equation 47. Introducing a multiplicative correction factor <p the equation for flow with no loss becomes: Avf> . to = x/Zgnip, - p,) By comparison with Equation 35, (54) 0= From Equations 34 and 35, * P, 1 -- y) 2 Pi (pi/ps) - 1 Mt'/MJ = 0*(p,/p,)'k (55) (56) 82 CHAPTER 4 Hence, by Equation 38 for a" small value of Mh 1954 Guide r * V Pl/P,) - i/ (p.M) - i i -1p(p*/p.)" From Equations 37 and 56, if Mj is not too large, -; .. 2- -A (v- - l) ~ 1 - /S* + iU - 2{k - 2)pWS k MS \pj / so that, approximately, ( (58) > (59) Fluid Flow 83 Installation of Head Meters . ' In the installation of Venturis, orifices, and nozzles, care must be taken 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 straightening vanes, as described more fully in References 2 and 5. The static pressure difference across the head meter is measured by suitably located static pressure taps. For orifices, the different sets Of pressure taps are called flange taps, radius taps, vena contracta taps, and pipe or full-flow taps. The relative locations of the first three of these are shown in Fig. 16. The need for applying suitable coefficients to measure- where to the same degree of approximation from Equation 36 M? = 2, P- i - Pi fcpi (60) Values of <fi are also given by Figs. 13 and 14. . While <t> may be used for smooth nozzles and Venturi tubes, it is necessary in the case of orifices, where the departure from ideal flow is significant, to replace <j> by an empirical factor Y obtained by the equation Y = 1 - (0.41 + 0.35ffl)^Pl -- /kj (61) When this correction is used, the flow will be given by the equation w = KAzYy/"2gpi(pi - pd (62) a. h------- A----------4 a ------------- 1 B_il -- 7 = 20 B 0.4 0,/D, Fig. 15. Minimum Conditions to be Observed When Installing Orifices and Nozzles Between Fittings and Valves ments obtained 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 2| pipe diameters upstream 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 had 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 corners formed by the pipe wall and the orifice plate. 84 CHAPTER 4 1954 Guide 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 pressure tap of the vena contracta arrangement is variable. Vena'contracta is the term 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 contracta tap, vary with the ratio of orifice to pipe diameter, 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 ready for installation. In such cases, the manufacturer's instructions should be followed "with'care Fluid Flow 85 For compressible flow, the differential head is to be divided by the correc tion F,, from Equation 64, . = 1 + iM> + *Af* (64) M' = 2 ---P kp 1 (65) In the use of a Pitot tube system, care is required in obtaining correct total and static pressures. The total pressure tube must be smoothly constructed, and should point directly 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. Fig. 16. Relative Location op Flange, Radius and Vena Contracta Taps 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 impracticable to use standard orifices, and consequently, either a specially designed orifice must be calibrated, or an independent 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 51). The difference in liquid level in the manometer will be proportional to the square of the velocity, for incompressible flow, so that in general >' V = Vfyht (63) Fig. 17. Location op Vena Contracta in Relation to Ratio op Orifice to Pipe Diameter and to Rate op Flow In rectangular ducts or near valves or fittings, a disturbed flow pattern would be obtained, and therefore, 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. . Variable Area Flow- Meters For permanent installations where high precision, ruggedness, 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, however, 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 86 CHAPTER 4 1954 Guide 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 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, vi(pi -- p), is balanced by the pressure difference acting on the cross-section area of the float, ArAp, where pi, Af, vi, are, respectively, the float density, float cross-section area, and float volume. Accordingly, the difference in head across the annulus is given by = P Atp . (66) CAPACITY. SCALE 'OR REFERENCE SCALE _ TAPERED TRANSPARENT METERING TUBE Fig. 18. Schematic Diagram of Variable Area Flow Meter The volume flow follows from equation (53) as Q = Tf/i i\/'igviipt - p)IpAj (67) . and the mass flow as w = pQ = KAi\/2gvt(pi -- p)-p/A, (68) The flow for any selected fluid is, accordingly, very nearly proportional to the area, so that a convenient calibration of the tube may be obtained. The behavior of. the flow coefficient, K, has been investigated6 and the ac tion of the flow meter as just outlined, experimentally confirmed. The flow 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 sizes calibrated Fluid Flow 87 for specific fluids by the manufacturer. The compactness, reliability, and ease of installation are particularly advantageous when many measure ments of essentially the same type are to be made. ..' . . , . - , LETTER SYMBOLS USED IN CHAPTER 4 0 = ratio, throat or orifice diameter to pipe diameter. p = 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. p,, = density of water at 60 F (62.37 lb per cubic foot), pi = density of float in variable area meters. ij> = expansion factor for nozzles. . 0 = 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. cp = specific heat of gas at constant pressure. Ci = specific heat of gas at constant volume. . D -- diameter of fluid stream, feet. ' d = internal diameter of pipe, feet. . dH = hydraulic diameter, feet, e = absolute roughness of pipe surface, feet. Fc = correction factor for differential head in compressible flow. / = dimensionless friction coefficient. g = gravitational acceleration, feet per (second) (second), ffe = gravitational conversion factor = 32.174 (pounds mass per pound force) X feet per (second) (second). . h = enthalpy, Btu per pound of fluid. hi - loss of head, feet of fluid. hi = total head, feet of fluid. J = mechanical equivalent of heat = 778 foot pounds per Btu. K = flow coefficient (correction factor), including velocity of approach,correc- tion factor, for flow through orifice, nozzle or Ventun. k = ratio of specific heat at constant pressure to specific heat at constant vol ume. L = perpendicular distance from axis of pipe, feet. 1 = length of pipe, feet. M = Mach number. = Reynolds number. . V = pressure, pounds per square foot. p = stagnation pressure. Vt -- critical pressure. Q = discharge rate, cubic feet per second. q = heat transferred to the fluid per pound of fluid flowing, it = gas constant. t = radius of pipe in feet. s = entropy of fluid in Btu per (pound) (Fahrenheit degree). T = temperature, Fahrenheit degrees, absolute, u = internal energy, Btu per pound of fluid. V = velocity, feet per second. ' Vc = critical velocity, feet per second. v = specific volume, cubic feet per pound. IF = mechanical work, foot pounds per pound of fluid flowing. = mass flow of gas, pounds per second. y = expansion factor--correcting for expansion of gas under reduced down stream pressure. 2 = elevation above some arbitrary datum, feet. 1 Friction Factors for Pipe Flow, by Lewis F. Moody (ASME Transactions, 66, 1944, 671-678; Discussion, idem. 66, 1944, 678-684); also, An Approximate Formula for Pipe Friction Factors ([Mechanical Engineering, 69,1947, 1005-1006). CHAPTER 4 1954 Guide 88 * Fluid Meters, Their Theory and Application (American Society of Mechanical Eng1 iFnleoewrsM, 4eathsuEredmiteionnt,, P1o9w3e7)r. Test Codes, Part 5, Chap. 4 (American Society of Me cha*nSictaanl dEanrgdisnefeorrs,D1i9s4c9h)a. rge Measurement (National Adv-isory Committee for Aero nautics, NACA Tech. Mcrn'. 952, 1940) (Translation of German Industrial Standard 1932G). as Measurement Committee Report No. 2, Natural Gas , Department (Amer ican* TGhaesFAlosswoMciaetciohna,ni1s9m48a).nd Performance of the Rotame. ter, by E. M. Schoenborn, Jr. and A. P. Colburn (Institute of Chemical Engineers, Transactions, 35. 1939, 359 381). ' BIBLIOGRAPHY [A] Thermodynamics, by Edward F. Obert (McGraw-Hill Book Company, 1948). [B] Thermodynamics of Fluid Flow, by Newman A. Hall (Prentice-Hall, Inc., 195[C1)]. Fluid Mechanics, by Russell A. Dodge and Milton J. Thompson (McGraw- Hil[lDB] oFolkuiCdoM.,e1c9h3a7n)i.cs, by R. C. Binder (Prentice-Hall, Inc., 2nd Edition, 1949). [E] The Physics of Solids and Fluids, by P. P. Ewald, H, Poschl and L. Praiidtl (Bl[aFc]kAie,S1t9u3d6y). of the Data on the Flow of Fluids i.n Pipes, b.y..E.m..ory Kemler, Hy draulic Paper HYD-55-2 (A.S.M.E. Transactions 65, No. 10, 7-22, 1933; Discussion, ide[mG.], T55h,eNFolo. w10o, 2f 3F-l3u2id,1s9i3n3)C. losed Conduits, by R. J. S. Pigott (Mechanical Engi nee[Hrin]gF6lu5,id1M93e3t,e4rs9,7-T5h0e1,ir5S1e5l)e. ction and Installation (American Society of Mechanical Eng[Iin] eTehrse, O19ri3fi3c)e. Meter for Measurement of Flow of Gases and Liquids, by Allen D. MacLean (Pittsburgh Equitable Meter Co., 1938). [J] Pitot Tube Practice, by Edward S. Cole (A.S.M.E. Transactions 57,1935, 281 294[;ItD] isPciutosst iTonu,beidseimn.L5a8r,g1e9P36ip, e1s4,6b-1y56E)d. ward S. Cole and E. Shaw Cole (A.S.M.E. Transactions, 61, 1939, 465-473; Discussion, idem. 61, 1939, 473-475). [L] Investigation of Errors of Pitot Tubes, by C. W. Hubbard (A.S.M.E. Trans actions, 61, 477-497; Discussion, idem. 61, 1939, 497-506). [M] Piping Arrangements for Acceptable Flowmeter Accuracy, by R. E. Sprenkle (A.8.MJS. Transactions, 67, 345-357, 1945; Discussion, idem. 67, 357-360,1945). CHAPTER 5 IIEAT TRANSFER Conduction, Convection, Radiation; Equations for Conduction, Convection,1: Radi ation and Combined Convection and Radiation; Heat-Flow Resistance; in Series and Parallel; Practical Heat Transfer Problems; Periodic and Transient Heat Flow HEAT is the form of energy that is transferred by virtue of an existing temperature difference. The temperature difference is the potential which causes the transfer, the latter in turn being resisted by the thermal properties of the material combined in a single term known as the resist ance. Energy exchange associated with evaporation, condensation, etc., is treated elsewhere such as in the section on cooling tower design in Chapter 35. The objectives of this chapter are to: 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 steady-state problems (tem perature 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 analysis for transient and periodic heat transfer problems. Further applications to specific systems will be found throughout The Guide. CONDUCTION, CONVECTION AND RADIATION Thermal conduction is the term applied to the mechanism of heat trans fer 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 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, thermal conduction is significant in the region very close to a solid boundary or wall, for in this region the flow is laminar, parallel with the wall surface, and there are practically no cross currents the direction of the heat transfer across the solid fluid boundary. In solid bodies the significant mechanism of heat transfer is always thermal conduction. ' Contrasted to the thermal conduction mechanism, thermal convection involves energy transfer by eddy mixing and diffusion1 in addition to conduction. This is shown schematically in Fig. 1 which exhibits transfer from a pipe wall at surface temperature t, to a colder fluid at a bulk tem perature L. (Bulk temperature is that which would be attained if the fluid stream were drawn off at a certain section and mixed. It is therefore somewhat higher than the lowest temperature in the stream.) In the laminar sublayer, immediately adjacent to the wall, the heat transfer th01^8 thermal conduction; in the transition region, which is called the buffer layer; eddy mixing as well as conduction effects are significant; 90 CHAPTER 5 1954 Guide in the eddy or turbulent region the major fraction of the transfer occurs by eddy mixing. In most commercial equipment the main body-of the fluid is in turbu lent flow, and the laminar film exists at the solid walls only, as shown in Fig. 1, but in cases of low-velocity flow in small tubes, or with viscous liquids such as heavy oil (low Reynolds numbers), the entire flow may be laminar. In these latter cases there is no transition or eddy region. When the fluid currents are produced by sources external to the heat transfer region, as for example by a pump, the described solid to fluid heat transfer is termed forced convection. In contrast, if the fluid currents are generated internally, as a result of non-homogeneous densities arising from the temperature variations, the heat transfer is termed free convection. In the conduction and convection mechanisms, the transfer of heat is associated with matter. For radiant heat transfer, however, a change in Heat Transfer 91 Expressions of conductivity used in the heating field are usually incon sistent in this sense, in that it is customary to refer to the conductivity per square fool but for one inch of thickness. This custom has been adopted for the reason that wall thicknesses are usually expressed in inches, whereas if expressed in feet, decimal or fractional thicknesses would result. When dealing with flat walls, no complication is involved in using the inconsistent expression of conductivity. However, where curved or spherical walls are concerned, considerable complication is involved. Therefore, in this discussion the consistent units of conductivity .expressed in Btu per {hour) {square foot) {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 12. As an example, the conductivity of brick listed as 5.0 in Table 2 of Chapter 9, becomes 0.42 when used in the calculations of this chapter. Fig. 1. Thermal Convection Conditions energy form takes place, from internal energy at the source to electromag netic energy for transmission, then back to internal energy at the receiver. The rate of heat transfer, corresponding to the three transfer mech anisms 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 being proportional to the potential. The convection and radiation flow rate expressions may be approximated by a potential (tem perature difference) and a resistance in order that heat transfer calculations may be effected more conveniently and rapidly. Thermal Conduction Equation Equation 1 states symbolically that the thermal conduction per unit transfer area normal to the flow, q/A, Btu per (hour) (square foot), is proportional to the temperature 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). I * ST. (1) The minus sign on the right side of the equation is introduced to indicate positive transfer in the direction of decreasing temperature. Fig. 2 shows the physical significance of the indicated quantities. It should be. emphasized that the thermal conductivity used should be expressed in consistent units; either using the inch or foot throughout. Fig. 2. Thermal Conduction in a Flat Slab Also, it should be emphasized that in order to make the calculations and applications consistent in this chapter, all dimensions of thickness must be expressed in feel. Thermal Convection Equation - = Kki. - ti) A (2) This rate equation states that the thermal convection per unit transfer area {q/A), Btu per (hour) (square foot) is proportional to the tem- nri AVAlUlAlEi Conductivity, k -- Btu per (hr) (sqfi) (F deg per in.) Material Air. .. Aluminum Brass (70 - 36). Cast-Iron. popper..................... uiass. k 0.168 1416.0 720.0 336.0 2640.0 3.6-7.32 Material ateoXfiS" , depend to some extent on temperature. my. Refer to Chapter 9, and Reference i for additional data. k 240.0 408.0 2.4-12.0 312.0 4.08 92 CHAPTER 5 1954 Guide perature difference (t, -- 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 conductance (sometimes called the film coefficient for convection), h,, Btu per (hour) (square foot) (Fahrenheit degree). Fig.' 1 shows the conditions associated with con vection. The heat transmission by free or natural convection for objects sur rounded by. air can be conveniently expressed as in Equation 2a: where heat transmission by convection, Btu per (square foot) (hour). a constant depending upon the shape of the surface, diameter of pipe or circular duct or height of vertical wall, inches. (Effect of diameter or height becomes constant at 24 in.), average of wall surface.and surrounding air temperature, Fahrenheit degrees absolute. temperature excess between wall surface and surrounding air, Fahren heit degrees. . For horizontal cylinders, the value of C = 1.02 has been well estab lished by various investigations. For vertical plates, the value of C = 1.39 has been fairly well established. Suggested values2 of C for hori zontal 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 convection may be solved by the simple first-power equation if the convection coefficient is expressedas a unit conductance: q - h0 A (i, - f,) (2b) where q = heat transmission by convection, Btu per hour. A = surface area, square feet. _ t, -- f, = temperature difference between the surface and the fluid, Fahrenheit degrees. hc = unit convective conductance, from Table 2, Btu per (square foot) (hour) (Fahrenheit degree temperature difference). Thermal Radiation Equation The relation given by Equation 3 is applicable to systems in which radiant exchange takes place between the surfaces of solids, as schemati- - qr = vA.FaFe (2V - ZV) . (3) cally shown in Fig. 3. Gaseous and luminous radiation are not considered in this discussion. Equation 3 states that the net radiation per unit trans fer area of surface 1, qjA Btu per (hour) (square foot), which sees surface 2 through a non-absorbing medium, is proportional to the difference of the Table 2. Approximate Unit Conductances fob Thermal Convection Several Flow Systems pob CHAPTER 5 94 Table 2. Approxima_t__e U_ nit CONDC Several Flow ffijESF' 1954 Guide Free convection pact n heated horizontal ' cylinder ' 1 v\M ^' . , Free convection poet a single vertical sur face- 13 Free convection pact a heated horizontal surface (face up)-, Equation for Air ( PY" " ic = \Po/ VI/ 10* < WCr < 10' / p \* w /A/y * Ac ss o.4zo [jr) Kj) 10* < Ngt < ln Equation for Air 10* < *Gr < 10? Equation for Air Ac 10> < 1*Or < Ffrreeee ctuounvtcecvtiiuon...,p_a_s_t a heated horizontal I* Fluidssuuprrrffaaoccpeeer((tfileaacsceeshddooouwwldnn))b.. e evaluated at the j arithmetic mean fluid temperature, tt = (* surface + t fluid) divibdTehdesbeye2x.pressions a.re suitab. le approximations to longitudinal flow in o`ther than right circular cylinders, provided the hydraulic diameter is employed as the conduit dimension parameter. For non-circular cross' sections, the hydraulic diameter is equal to four times the cross-sectional area divided by the wetted perim etere. For` lo' w rate..s....o..f...h...e..a...t transfer by free c" on` vection the exponent decreases towards zero, and for h^igher rates, increases towards 0.33. The above equations employing an exponentequal to 0.25 are applicable in the intermediate range indicated. NOMENCLATURE AND DIMENSIONS FOR TABLE 2 . cB = heat capacity at constant pressure, Btu per (pound) (Fahrenheit degree). . D = cylinder diameter, feet. f * subscript denoting film. Heat Transfer 95 g = body force per unit mass, feet per hour per hour. (For static system on earth, g = 32.2 X 36001 feet per hour per hour.) G -- 3600 Uap = mass flow per unit cross-sectional area normal to flow, pounds per (hour) (square foot of flow cross-section). No, = Grashof modulus, dimensionless. (JVo, = D,ptfihtg/ii`). hc = average unit thermal convective conductance from the leading edge of surface to the position x, Btu per (hour) (square foot) (Fahrenheit degree), hex = local unit thermal convective conductance, at the position x 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). - 1 = a dimension of the system, feet, m = a subscript denoting mean. P = pressure, atmospheres. P,, = pressure (atmospheric) atmospheres. t -- temperature, Fahrenheit. T = temperature, Fahrenheit, absolute, ti = fluid veldcity, feet per second. V = volume, cubic feet, x = a dimension of the system, feet. . 1 dV P = coefficient of cubical expansion 03 = ^(^)p); for perfect gases P -- \/T. &t = difference between wall and fluid temperatures, Fahrenheit degrees. r = fluid viscosity, pounds per (hour) (foot). .. p = density, pounds per cubic foot. : "> = infinity, referring the quantity to a point not'directly affected by the phenomenon in question. Table 3. Radiation Factors or Emissivities, F.or the determination of factor Ft: in Equation 3 Class Surfaces Fraction of Black-Body " Radiation At 50-100 F At 1000 F Absorptivity - FOB Solar . Radiation 1 2. 3 4 5 6 7 8 9 --_____ A small hole in a large box, sphere, furnace, or enclosure............................................................................ Black non-metallic surfaces such.as asphalt, car bon, slate, paint, paper............................................... 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......................................................... 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......................................................... :............. 0.97 to 0.99 0.90 to 0.98 0.85 to 0.95 0.85 to 0.95 0.85 to 0.95 0.40 to 0.60 0.20 to 0.30 0.02 to 0.05 0.02 to 0.04 0.97 to 0.99 0.90 to 0.98 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 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 Emissivities of other materials may be found in Reference 4. a Reflects about 8 percent. fourth powers of the absolute surface temperatures (2V -- 7V). The pro portionality factor (cFaFe) may be conveniently separated into three parts (excepting in some problems involving interreflections, where it is not possible to divide the product (FaFe) into separate terms): v => the Stefan-Boltzmann radiation constant = 1730 X 10 11 Btu per (hour) (square foot) (Fahrenheit degree absolute temperature to the fourth power). "a = the geometrical factor which is dimensionless and si 1. This factor accounts for the shape and relative position of the two surfaces. The value of Fa = 1 may be used in the cases of large parallel planes, long concentric cylinders or smaller bodies in large enclosures.. . = the emissivity factor which is also dimensionless apd 1. This factor ac counts for the absorption and emission characteristics of the surfaces for the 96 CHAPTERS 1954 Guide: radiation which exists. Emissivities or absorptivities (). for many common surfaces, are given in Table 3. . The value of Fs for large parallel planes, long concentric cylinders, or large enclosed bodies is 1 (1/ei + 1/e, -- 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 wanner surfaces as high as 139 F. Some net radiation exchange solutions for several common radiation systems are given in Table 5. There are several methods by which the geometrical factors FA can be determined. One method involves the use of a mechanical geometrical integrator (Reference 8). Photographic and other methods are given in References 9 and 10. Equivalent Conductance for Radiation Although Equation 3 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 radiaiion by the equation: . 9, = h, A (tl -- t) (4) Table 4. Heat Transmission by Radiation for Black-Body Conditions* Expressed in Btu per (square foot) (hour) Temp F Deo 0 -1 -2 -3 -4 --5 -o -7 -a -9 -30 -20 -10 0 0 10 20 30 40 50 60 70 80 90 100 110 120 130 59.3 65.2 71.4 78.0 0 78.0 85.0 92.4 100 109 118 127 137 148 159 370 183 .196 211 58.7 64.7 70.8 77.4 58.2 64.1 70.1 . 76.7 +i 78.7 85.7 93.3 101 110 119 128 138 149 160 171 184 197 212 +2 .79.4 86.5 94.0 102 111 120 129 139 . 150 161 173 185 199 214 57.7 63.5 69.5 76.0 57.2 62.9 68.9 75.4 +3 +< 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 56.7 62.3 68.3 74.7 +5 81.5 88.7 96.4 105 113 123 132 143 153 164 176 189 . 203 218 56.2 61.7 67.7 74.0 +a 82.2 89.4 97.2 105 114 123 133 144 154 166 178 191 204 220 55.7 61.1 67.1 73.4 55.2 60.5 66.4 72.7 +7 82.9. 90.2 98.0 108 115 124 134 145 155 167 179 192 206 221 +8 . 83.6 90.9 98.8 107 116 125 135 146 156 168 180 193 207 222 54.7 59.9 65.8 72.1 . +? 84.3 91.7 99.6 108 117 126 136 147 157 169 182 195 209 224 * Example: Radiation from walls of room at 32 F to surface at -25 F for effective emissivity of 0.95 (102 -- 62.3) 0.95 = 37.7 Btu per (square foot) (hour). Heat Transfer 97 Table 5. Net Radiation Solutions System Solution Remarks -+--1 -- 'I'**) jGjnsrrfering inferreflecfiVm* 1 (Reference 5) - - - Two infinite parallel plants. 1eJdeJ or /i\ 1 2 " wie~i 71----i . Considering interreflectiona. I (Referenoe 5) One radiation shield between two infinite parallel planes. . im. eri3--s . 1 /er\ |^ogj^^ng interreflectiona. A n -f- 2 \Aso (5).where is the net radiation ex n radiation shields between two infinite parallel planes. change without the shields. o I^Hsjdenng interreflectiona (A, I + A/1 X e(Ti<- 7V9, and diffuse surface. (Ref *i At\ft / erence 5) Two concentric spheres or two infinitely long cylinders. Two areas dAi and dAt dqr _ dAi = tvrFA(Ti* -- 7V) (Surface diffuse, neglecting interreflection. ence 5) (Refer tOI* 'finitewSfTM* >ength = (0 - rr) [where AT is the length of cylinder from which Qr is exchanged en in- Neglecting interreflections. (Reference 5) P Surfaces are perfect radi atore. See Fig. 4 (Reference 4) ^MdnanSi11??^ ^tangle above tanef?^^ ^Si Wltt one Corner rec- tangte containedSiunrfancoersmaarletopderAfe. ct ra diators. - See Fig. 5 (Reference 4) planes! rectangles in perpendicular Surfaces are perfect ra diators. See'Fig. 6 (Reference 4) rectangles and disks cf 98 CHAPTER 5 1954 Guide F F dAPig. 4. Geometrical Factor ob Direct Radiation Between an Element . and a Parallel Rectangle* Heat Transfer 99 The conductance 'hi thus defined is a function of the shape-emissivity factor, as well as the temperatures of the radiator and receiver. Fig. 7 shows a plot of the equivalent conductance for two black bodies (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 computed separately. In many practical eases it is desirable to treat convection and radiation as a single combined process, using a first-power equation: ?re = Arc A (l, - 11) (5) where qIQ is the total heat flow due to radiation and convection, in Btu per hour. Values of Arc, the surface or film conductance for combined FFig. 5. Geometrical Factor for Direct Radiatton Between Adjacent Rectangles in Perpendicular Planes* Fig. 6. SIDE OR OiAMCTEft fcATIO 01STANC BETWEEN PLANES FGeometrical Factor bob Direct Radiation Between Opposed Parallel Rectangle and Discs of Equal Size* ..Rom Radiant Heat Tn.mmieetan, by H. C. Hottel (Monied July 1930, pp. 700 to 7021 Fig. 7. Equivalent Conductance for Radiation Between Two Black Bodies Exchanging Energy Only with One Another radiation and convection, are given in Chapter 9, (Table 1 and Fig. 4). Complete tables for the combined heat transfer of steam and hot water radiators, pipes, coverings, etc., will be found in the appropriate chapters. HEAT-FLOW RESISTANCE In most of the steady-state heat transfer problems encountered in air conditioning applications, more than one of the heat transfer mechanisms are effective, and the thermal current flows through several resistances in series or in parallel. In using the resistance concept, the calculations in volved are analogous to the application of Ohm's Law in electricity, viz., the heat flow or thermal current is directly proportional to the thermal potential or temperature difference, and inversely proportional to the thermal resistance: N 100 CHAPTER 5 1954 Guide Following the electrical analogy, when there is a thermal current flowing through several resistances in series, the resistances are additive: Rt ** Ri ~b Ri ~b Ri -b '" ~b Rb (7) Similarly, conductance is the reciprocal of resistance, and for heat flow through several resistances in parallel, the conductances are additive: ,, 1111 1 Ct -- ~ -- -j- -- 4- -- 4* 4- -- Rt Ri R* R, Ru (8) Practical Heat Transfer Problems The use of these relations for resistance and conductance makes pos sible the solution of many practical heat transfer problems. As discussed in Chapters 9, 28 and 36, the practical 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 Fig. 8. Heat Transfer Conditions in an Insulated Cold Wateb Line steady-state conduction problems. Table 6 gives the resistances in six common cases of steady-state conduction. A complete analysis by the resistance method is well illustrated by considering the heat transfer from the air outside to the cold water inside of an insulated pipe. The temperature 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 radiation into main cold water streams. (Radiation is not significant on the water side as liquids are sensibly opaque to radiation, although water, transmits energy in the visible region). The contact resistance between the insula tion 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, grc, Btu per hour, may be thought of as flowing through the parallel resistances R, and Rc, associated with the insulation surface radiation and convection transfer. Then the flow is through the resistance offered to thermal conduction by the insulation, R3, through the pipe wall resistance, Heat Transfer 101 Table 6. Solutions fob Some Steady-State Tbebmal Conduction Pboblems*. No. System Expressions for the resistance B entering into the equation: ^. Q -- At/R (Btu per hour) ^t w^l or curved wall if curvature is small ^thickness less than 0.1 of inside dia- Surface area, A Radial flow through a right circular cylinder '"1a. iog^ ' 2rkN (See footnote c). Radial flow in a hollow sphere. log. + Va + rjJ ^h-i (w, + S = tScN " . tikN For * 3, satisfactory approximation is: , 2o , a log -- cosh-1 2tkN 2*kN 4A The straight fin or rod heated at one end. . *- Conduction cross-section area. A Ambient Fmned surface of area HB. a ~ htp tanh mL` (see footnotes d and e). For T7it > 2.3, tanh nL 1 m = >/htP/kA A -- conduction cross-section area. p = perimeter of cross-section A. = unit conductance to the surroundings from the fin surface. .' A = thermal conductivity fin'material. At ~ wall temperature--ambient temperature ( 4- 4) it = / o .: \ kt f ~ tanh m l-f ^ BB Surface area, H6 At defined as in Case 5 above. .,,* b The t_h_e_r_m..a.l Uc.o5n1CdQu;c, tuivuitiyu,j oAi, ainretah,ease =sosluqtuioanres tseheot.uld be taken at the . average _ _____ , (square material temperature. * Log* x 2.303 logw*. d The expression can also be employed as an approximation for tapered fins or of annular fins by em ploying average magnitudes of A and p e tanh is the hyperbolic tangent. 102 CHAPTERS 1954 Guide Rt, and into the water stream through the convection resistance, Rt. Note the analogy to the direct current 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 4 R? 4~ Ra 4 Ra (9) where the resultant parallel resistance R, is obtained from . ill . r,=5;+r,, .(10,,) Provided the individual resistances may be evaluated, the total resistance can be obtained from this relation. Then the heat transfer for the length of pipe (N, ft) can be established by the relation q,, (Btu per hour) = --- Ht For a unit length of the pipe the heat transfer rate is I;0 Btu per (hour) (foot) = ^ -- N KtJ\ (11) (12) The temperature drop, At, through an individual resistance may then be calculated from the relation: At = R (13) where R is the resistance in question. The problem is now reduced to one of evaluating the individual resist ances of the system. This entails suitable manipulation of the rate Equa tions 1, 2 and 3 to produce expressions of the form: At q= (14) where q is the heat transfer rate, and At is the potential drop or tempera ture difference through the resistance R. Table 6 lists such solutions for six different conduction systems. Table 2 in Chapter 9 and Table 1. of this chapter indicate the magnitudes of the thermal conductivities, k, to be employed in the expressions of Table 6, after dividing k by 12. The solution applicable to the problem depicted in Fig. 8, for the cal culation of Ri and R3, is case 2 in Table 6. Thus for a 1 ft length of 2 in. nominal size pipe (I. D. = 2.067 in., O. D. = 2.375 in.) insulated with 1 in. of material having a conductivity of 0.025: 1.188 l0ge 1.033 Ri = 2, X 26 X 1 = 8.5 X 10-4 (hr) (F deg) per Btu. 2.188 log* R. = 2t X 1.188 0.025 X 1 = 3.9 (hr) (F deg) per Btu. Heat Transfer 103 The convection resistances to heat transfer from the pipe wall to the cold water, Ri, and from the air to the surface of the insulating material, 12c, 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 problem statement, a tempera ture 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 tempera ture difference between the temperature of the fluid body and the tempera ture of the pipe wall. For the purpose of an initial guess, this temperature difference will be assumed to be 2 deg. On the other hand, hc for heat transfer from air to a body is relatively small, and a higher temperature difference would be expected between these masses. The value initially assumed here will be 20 deg. In 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 = 100 F. Ambient air temperature = 120 F. With these assumptions and the problem statement, it is now possible to calculate values for the convective resistances. If it is found in the ultimate solution of the problem that the temperature distribution is different from that assumed, it will then be necessary to repeat the solution procedure. 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 convection between the water and the pipe wall. The equation for this case is the following: where A,, = 13.9(h)0 i/'J Um = 5 [pa D = 2.067 12 = 0.1725 ft 34 + 36 It 2 = 35F = 139 Xq67q3X ~'62 = 494 Btu per (hr) (sq ft) (F deg). (15) This heat transfer rate is through the inner surface of the pipe and it is, therefore, this area that determines the resistance R\. and therefore A = *D = 0.542 sq ft per unit length of pipe, R' = hjt " 494 X 0.542 Ri = 3.73 X 10-* (hr) (F deg) per Btu. 104 CHAPTER S 1954 Guide Case 11 of Table 2 fits the conditions of the problem if only free convec tion heating of the pipe is assumed. The equation in thiscase is as follows: {wT(3TK = 0.271 (16) where' therefore, At = 20 F D = 0.364 ft P = Po = one atmosphere he = 0.737 Btu per (hr) (sq ft) (F deg). Using the surface area of the insulation, the value of the resistance per unit length is determined. . A =x X 1 = 1.14 sq ft ,,_ 1 _ 1 KA 0.737 X 1.14 Rc -- 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. = 0.2ll(!r,)o-(hu^d)L0--8 (17) _ 100 + 120 ^ '2 (Fahrenheit absolute) = 7 fps p = 0.0694 lb per eu ft and D = 0.364 ft 0.211(570)-u(7 X 0.0694)-8 ke(av*rage) -- (0.364)0-4 hc(.r.) = 2.73 Btu per (hr) (sq ft) (F deg) B,, (Forced Convection) = = 2 73 X 1.14 . Rs = 0.321 (hr) (F deg) per Btu. The radiation resistance, Rr, which acts inparallel with the resistance just calculated, can be computed with the aid of Fig- , Pt^ raassumed at 100 F sees the surroundings at 120 F. If these two tempera Heat Transfer 105 tures are used'with Fig. 7, a value for vrL- is determined directly. r aFe , = 14 Btu Per (hr) (F deg) (sq.ft). The angle factor, FA, is unity, and for an.estimated surface emissiyity of 0.95 (see Table 3), FE = 0.95. Therefore, . . V= 1.4 FaFe = 1.4 X 1 X 0.95 , hr = 1.33 Btu per (hr) (F deg) (sq ft) and the radiation resistance, Rr, is then the following: *" hr A 1.33 X 1.14 Rr = 0.659 (hr) (F deg) per Btu. The resultant resistance of Rc and R, acting in parallel (see Fig. 8) can now be evaluated as: . -- = -- + -- = --i---F -----= 4.54 Btu per (hr) (F deg) R, Rr Rr 0.321 0.659 v 6 R4 = 0.216 (hr) (F deg) per Btu. The overall resistance, Rt, surroundings to cold water, is the sum of Ri + R2 + Rz -H Rt = 4.12 (hr) (F deg) per Btu for 1-ft length of pipe.. Note that the controlling resistances are R3 and Rt, and that neglect of both Ri and Ri would not significantly influence the total resistance, Rt. On the basis of this resistance calculation, the heat transfer from the surroundings to.the cold water may be evaluated as: = ltT l' = ~77o"" = 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, ! . ' ?rc = 20.8 Btu per hr. . The temperature drops through the various resistances are now readily evaluated by Equation 14 as: . At = qR - <0 -- ta (air to insulation surface) = qRi = 20.8 X 0.216 = 4.49 F deg ta -- < (through the insulation) = qR, = 20.8 X 3.9 = 81.2 F deg - fn (through the pipe wall) = qRt.=> 20.8 X 8.5 X 10-4 = 0.018 F deg hi tt (pipe wall to cold water), -- qR, = 20.8 X 3.73 X 10"* -- 0.078 F deg . This solution was obtained on the temperature distribution assumptions initially! made. It- is apparent that a better solution could be obtained if the whole problem were reiterated using the temperature distribution just calculated. . 106 CHAPTER 5 1954 Guide 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 problems the heat flow depends upon time. Such cases can usually be divided into two classes: periodic and transient. Periodic heat transfer repeats periodically in time. Transient heat transfer exhibits no periodicity. Graphical, ana lytical and numerical methods are available for solving transient or periodic heat flow problems.4'6-*10*'11,12 Graphical and numerical methods are the most versatile, and can be applied with minimum mathematical training. A large 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 and tabulated. Many more analytical solutions are available in the form of infinite series,11'12'18'13 *b*u*t*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 to treat analytically. In such cases, recourse may be made to a graphical method of solution sometimes called the Schmidt method.410'19.'2*1'22 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,6'21 and also, for one dimensional (radial) heat flow in spheres and cylinders.22-23 , . . ' Heat Transfer 107 Table 7. Analytical Solutions fob Heat Conduction in Vabiously Shaped Solids Shape op Solid Boundaby Conditions Data Available in Gbaphb Semi-infinite Surface temperature changed. suddenly Temperature distribution in solid as a function of time. References:(4) p. 37, (5) p. V-28; (10) p. 254; (13) p. 46. X--WGD A steady flow of heat is suddenly ap plied to the surface. The surface temperature has been varying sinusoidally with time for a long time. Heat flow from surface as a function of time. References: (10) pp. 256,267; (13) p. 47. Temperature distribution as a func tion of time. Reference: (10) p. 257. Temperature distribution as a func tion of time. Reference: (10) p. 296. . Semi-infinite with fluid at free surface. The temperature of the fluid in con tact with the surface has a sudden change in temperature. (Thesurface conductance is constant). Heat flow from surface as a function of time. Reference: (10) p. 296. Temperature distribution as a func tion of time. References: (4) p. 37; (5) pp. V-45,46, % Slab. The temperature of the fluid in con tact with the surface been varying sinusoidally with time for a long time. (The surface con ductance is constant.) The temperatures li and t* are sud denly changed from the initial uni form slab temperature to a new temperature. (The case where the surface on one side is insulated 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 func tion of time. Reference: (10) p. 298. Heat flow from the surface as a func tion of time. Reference: (10) p. 298. Temperature distribution as a func tion oftime. References: (5) p. V-12; (10) p. 265. The temperatures ti and h suddenly begin to increase as linear func tions of time. The slab is in itially at uniform temperature. (The case where one surface is insulated against heat flow is treated as noted above.) Temperature distribution as a func tion of time. ' Reference: (10) p. 268. The temperature at both surfaces has been varying sinusoidally for a long time. Temperature distribution as a func tion of time. Reference: (10) p. 300. Slab immersed in a fluid with constant conductance be- i tween fluid and slab surface.. The temperature of the fluid is sud denly changed from the initial uni form slab temperature. (If one surface is insulated against heat flow, see above.) %% hc, ki Heat flow from the surface. Reference: (10) p. 303. Temperature distribution as a func tion of time. References: (4) pp. 32, 33 , 34, 35; (5) pp. V-9, 10,35,42; (10) pp. 274,284; (13) p. 106. Heat flow from the surface as a func tion of time. References: (5) p. V-10; (10) p. 274; 03) p 107. y The temperature of the fluid at one surface varies as a periodic func tion of time while the temperature of the fluid at the other surface is constant. The conductances need not be the same on both sides. (The variations in temperatureare expressible as a Fourier series.) Temperature distribution as a func tion of time. Reference 14. Heat flow at the surface as a function of time. Reference 14. CHAPTER 5 1954'Guide 108 Table 7. Solutions fob Heat Conduction in Variously Shaped Analytical c-------- Shape of Solid . Cylinder of infinite axial di mension ' Boundary Conditions Data Available in Graphs The surface temperature is suddenly changed from the initial (uniform; Temperature distribution as a *une- tion of time. Reference'. (10) p. 265. .i ,Heat flow from surface as a function of time. Multiply temperature difference be- tween surface and fluid by surface conductance. 1 % i ' Cylinder of infinite axial di . mension immersed in a fluid. The surface temperature suddenly begins to increase linearly with time. ' The surrounding fluid suddenly changes from the initial (uniform) temperature of the cylinder. Temperature distribution as a function of time. --- ----Reference: (10) p. 269. ,TTemperature distribution as a func tion of time. 4 References: (4) p. 36; (5> pp. V-16, V-35, V-43, V-48; (10) pp. 278, 286; (15). 5. A ' i. - 1 Heat flow from the surface as a func- tion of time. ,' References: (5) p. V-16; (10). p. 278. St ^ The temperature of the surrounding fluid changes sinusoidally. Temperature distribution as a func- _ _tion of time. , .Reference: (5) p. Vi-34. . v a % sphere Sphere immersed in fluid. Qi tion of time. _ Reference: (5) p. VI-36. The temperature of the surface is suddenly changed from the initial uniform temperature. Temperature distribution as a func' tion of time. References: (5) p. V-23; (10) pp.264, 265. The temperature at the surface sud denly begins to change as a linear Temperature distribution as a func tion of time. - The temperature of the surrounding fluid suddenly changes from the ipitiftl uniform sphere temperature- Temperature distribution as a func- tion of time. , References: (4) p. 36; (5) PP* Y."?'* V-35, V-44; (10) pp. 281, 282; (4). Heat flow as a function of time. References: (5) p- V-21; (10) p. 281. V Lv *' 5 ^ Rectangular bar of infinite length. Any of the above noted boundary conditions for a slab. Temperature distribution as a func- tion of time. . _. , , . Combine solutions as indicated m . Refs. 16 and 17. t > a Parallelepiped (rectangular) Any of the above noted boundary conditions for a slab. Temperature distribution as a tunc- tion of time. Combine solutions as indicated m Refs. 16 arid 17. ^ V? .y. Cylinder of finite length. Any of the boundary conditions i given above for a cylinder and a slab. . Temperature distribution as a func- tion of time. . ,. Combine solutions as indicated m Refs-16 and 17. *- S'v ^ Hollow cylinder of infinite ex terior radius. The temperature of the surface sud denly changes from the initial (uniform) temperature. ---------------------------------- ---:---------- . ~ Temperature distribution as a func tion of time. . ` ... Combine solutions as indicated m Refs. 16 and 17. . -, % f* Heat flow at the surface as a func tion of time. ___ Reference: (10) p- 267. ------------------ ------------------------------------ % ilaCnoensspidaerraltlheel toslathbetoslabbe sduivrfiadceeda, nads ashdoiswtnanicneFAisg.a9p,arbt.y nLeeqt uthiaeistiaemni-- ff ierature of. the slab at any plane and any time (0) be denoted by Txj. % rhen the temperature of the slab at the two adjacent planes at the same f Heat Transfer 109 time will be denoted as Tlx+Ax,o) and T(x^Ax,t). ' In a similar manner the temperature of the x plane at a time A0 later will be T(x,e+eA). . In accordance with this nomenclature, the temperature at any plane x and time 8 + A0 is given as m T(x+Ax.e) Tix--Ax,o) IfI.S+AB) = ------------------- ------------------ (18) which may be interpreted as follows.. The temperature of the slab at any plane, x, and any time, 0, is equal to the average temperature of the two adjacent planes obtained at the time (0 -- A0). . The time interval A0 is determined by the equation A* A0 = -- (19) Omitting the graphical construction at the slab boundaries, reference to Fig. 9 demonstrates the graphical method by means of which the tempera ture at each plane is determined at successive intervals of time in accordance with Equation 18. For the problem stated, the boundary condition at the insulated surface is specified by the equation 3T =0 dx and at the uninsulated face by the equation - T) = -k^ox In terms of finite differences these two equations (employing nomenclature established by Fig. 9) become Tf ---------- - = 0 or Tr = Tt, at, x = L Air. . and fc(T, - Ta.) = -k (Tb ~ Th- at x = 0 . Ax or - 7V = _ Ta - Tb k/h Ax The details of the graphical construction are best obtained by inspection of Fig. 9. Note that the line (0,0,0') used to initiate the graphical con struction, is the only one drawn to the slab boundary A'. The numbered points indicate temperatures at the sub-slab boundaries at 1,2,3, etc., time intervals (A0) after the slab is exposed to the high temperature. For transient heat flow in two dimensions, and also, for steady state conduction, numerical methods of solution are available in the literature.6-10'12'!9 These numerical methods 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 110 CHAPTER 5 1954 Guide the analogy of electrical resistance-capacitance networks to thermal systems.24 For two dimensional problems in steady state conduction, additional techniques of solution are found in flux plotting,8,19 and ip the use of a potential tank.5,19 These methods are of most direct use in problems in which the boundaries of the two dimensional shape are made up of. isothermal and adiabatic surfaces. REFERENCES 1 Absorption and Extraction, by T. K. Sherwood (McGraw-Hill Book Co., Inc., 1937). 8 The Transmission of Heat by Radiation and Convection, by Griffith and Davis (Special Report No. 9, 1933, Department of Scientific and Industrial Research. His Majesty's Stationery Office, London, England). 3 A Method of Correlating Forced Convection HeatTransfer Data and a Compari son with Fluid Friction, by A. P. Colburn (American Institute of Chemical Engineers ' Transactions, Vol. 29, 1933, p. 174). * Heat Transmission, by W. H. McAdams (McGraw-Hill Book Co., Inc.). * Heat Transfer Notes, by L. M. K. Boelter, V. H. Cherry, H. A. Johnson and R. C. Martinelli (University of California Press, 1946). e Heat Transfer by Free Convection from Heated Vertical Surfaces, by V. S. Touloukian, G. A. Hawkins and M. Jakob (A.S.M.E. Transactions, 1948, p. 13). I Heat Insulation in Air Conditioning, by R. H. Heilman (Industrial and Engineer ing Chemistry, Vol. 28, July 1936, p. 782). 8 Photoelectric Photometer for Rapid Comparison of Two Light Sources, by L. M. K. Boelter, J. T. Gier and F. A. Ryder (Illuminating Engineering Society Transac tions, 1939). . ... * Scientific Basis of Illuminating Engineering, by Perry Moon (McGraw-Hill Book Co., Inc., 1936). 10 Heat Transfer, by Max Jakob (John Wiley and Sons, Inc., Vol. 1,1949). II Numerical Methods in Engineering, by L. E. Grinter (The MacMillan Co., 1949). 18 Numerical Analysis of Heat Flow, by G. M. Dusinberre (McGraw-Hill Book Co., Inc., 1949). 13 Elements of Heat Transfer and Insulation, by Max Jakob (John Wiley and Sons, Inc., 1942). 14 Periodic Heat Transfer at the Inner Surface of a Homogeneous Wall, by H. A. Johnson (A.S.H.V.E. Transactions, Vol. 54, 1948, p. 143) 18 Temperature Charts for Induction and Constant Temperature Heating, by M. P. Heisler (A.S.M.E. Transactions, Vol. 69, 1947, p. 227). 18 Temperatures in Solids During Heating and Cooling, by F. C. W. Olsen (In dustrial and Engineering Chemistry, Vol. 34, 1942, p. 874). 17 Applied Mathematics in Chemical Engineering, by T. K. Sherwood and Charles E. Reed (McGraw-Hill Book Co., Inc., 1939). 18 Introduction to the Mathematical Theory of the Conduction of Heal in Solids, by H. S. Carslaw (Dover, 1945). 18 Heal Conduction, by L. R. Ingersoli, A. C. Ingersoll and O. J. Zobel (McGraw- Hill Book Co., Inc., 1948, p. 209). 80 Charts for Estimating Temperature Distribution in Heating or Cooling Solid Shapes, by H. P. Gurney and J. Lurie (Industrial and Engineering Chemistry, Vol. 15,1923,p. 1170). 81 Applied Mathematics in Chemical Engineering, by T. K. Sherwood (McGraw-Hill Book Co., Inc., 1949, p. 241). 88 Methods graphiques pour l'etude des installations de Chauffage et de refrigera tion en regime diseontinu, by'A. Nessi and L. Nissolle (Dunod, Paris, 1949). 88 Transient Heat Conduction in Hollow Cylinders after Sudden Change of InnerSurface Temperature, by R. L. Perry and W. P. Berggren (University of California Publications in Engineering 5, Vol. 59, 1944). 84 Method for Determining Unsteady-State Heat Transfer by Means of Electrical Analogy, by V. Paschkis (A.S.M.E. Transactions, Vol. 64, 1942, p. 105). CHAPTER 6 PHYSIOLOGICAL PRINCIPLES Chemical Vitiation of Air, Physical Impurities in Air, Thermal Interchanges Between the Body and Its Environment, High Temperature Hazards, Acclimati zation, Upper Limits of Heat for Men at Work, Application of Physiologic Principles to Air Conditioning Problems, Effective Temperature Index and Comfort Zones VENTILATION is defined in part as the process of supplying air to, or removing air from, any space by natural or mechanical means. The word in itself implies quantity, but air must be of the proper quality also. The term air conditioning in its broadest sense implies control of any or all of the physical or chemical qualities of the air. The A.S.H.V.E. Code of Minimum Requirements for Comfort Air Conditioning1 defines it "as the process by which simultaneously the temperature, moisture content, movement and quality of the air in enclosed spaces intended for human occupancy may be maintained within required limits. If an installation cannot perform all of these functions, it shall be designated by a name that describes only the function or functions performed." CHEMICAL VITIATION OF AIR People living indoors bring about certain physical and 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 off 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. Objectionable body odors have the same effects. These reasons, whether esthetic or physiological, usually make it desirable in the design of air conditioning systems to provide for the elimination or control of odors arising from occupancy, cooking, or other sources. This may be accomplished by introducing odor-free air in sufficient quantities to reduce odor concentrations by dilution to a level which is not objectionable. Odor-free air may be outdoor air or air which has been cleared of odors by sorption, washing, or other appropriate means. In the case of vitiation by a few-hazardous gases such as carbon mon oxide from heating, cooking, and certain industrial processes, no satis factory chemical treatment for the elimination of the impurity has been found. The only satisfactory solution is elimination at the source by local exhaust ventilation; or, if this is impossible, reduction to a safe concen tration by dilution. (See Chapter 8.) In the case of contamination by other matter, including volatile vapors and gases, chemical treatment for the removal or reduction of the impurities has been made available : through air cleaning methods, which are discussed in Chapter 34. When the only source of contamination is the human occupant, and over heating is not a problem, the minimum quantity of outdoor air needed ap Pears to be that required to remove objectionable body odors, or tobacco smoke. The concentration of body odor in a room, in turn, depends ill 112 CHAPTER 6 1954 Guide upon a number of factors, including the dietary and hygienic habits of the occupants (frequently reflecting their socio-economic status), the outdoor air supply, air space allowed per person, odor adsorbing capacity of air conditioning processes, and temperature and relative humidity. The in tensity of odor sensation has been found-to vary as the , logarithm of the concentration of the odoriferous substance in the air, or inversely with the logarithmic function of the amount of outdoor air supplied and the air space per person. . The relation between air supply and occupancy has been reported by the Harvard School of Public Health2 (Table 1) and the A.S.H.V.E. Research Laboratory.3 Outdoor air requirements for removal of objec tionable 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 outside air to be circulated through an enclosure is often governed chiefly by physical considerations for controlling tem perature, air distribution, and air velocity. Other factors which must be taken into consideration, include the type and usage of the' building, locality, climate, height of rooms, floor area, window area, extent of occu pancy, and the operation of the system distributing the air supply. Fre quently, 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. ;} | T It will be noted that, with adequate air space, the rate of air change indicated in Table 1 is from 10 to 30 cfm per person.. In rooms occupied by only a few persons, such an air change will be automatically attained in cold weather by normal 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 air changes per hour are necessary to provide a ventilation rate of 10 cfm per person. i 1 ? ' ' _ Therefore, in the ordinary dwelling with adequate cubic space allot- } ment, no special provision for controlling chemical purity of the air is 1 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), j where the cubic space per person is less and it is usually impossible to | admit untempered outside air without creating drafts, mechanical ventila tion is essential. -i The present data regarding the effect of cubic space on ventilation requirements are not universally accepted. The Code of Minimum Re- quirements for Comfort Air Conditioning1 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. | | |fj | | Notwithstanding the rapid advance made in air conditioning, some per- jj sons still believe there is a stimulating quality in outdoor air (particularly V country, mountain and seashore air) under ideal weather conditions, which f; is lacking in artificially conditioned air. It is apparent, however, that i modem air conditioning insures control of the phenomena of nature for I the service and comfort of man independently of weather conditions. | Freedom of movement, action and thought, together with the variability of stimuli experienced by persons under ideal conditions in the country, mountains or seashore, undoubtedly has some stimulating effect. Various J| experimenters have attempted to duplicate the invigorating qualities-of & Physiological Principles 113 Tabus 1. Minimum Outdoor Air Requirements to Remove Objectionable Body Odors Under Laboratory Conditions3 Type op Occupants Air Space per Person Cu Ft I Outdoor Air Rttpw.t CFM per Person Hailing season with or without circulation. Air not conditioned. jSedentary adults of average socio-economic status.... Laborers...... 100 200 300 500 200 25 16 12 7 23 jGrade school children of average socio-economic status Lrade school children of lower socio-economic status.... Children attending private grade schools _ 100 200 300 500 200 100 29 21 17 11 38 22 Heating season. Air humidified by means of centrifugal humidifier. Water atomization rate 8 to 10 gph. Total air circulation 80 cfm per person. Sedentary Adults-- 200 12 Summer season. Air cooled and dehumidified by means of a spray dehumidifier. Spray water changed daily. Total air circulation 80 cfm per person. Sedentary Adults-- 200 <4 outdoor air by the use of ozone, ionization, or ultra-violet light, but results to date have been inconclusive or negative.6 Ozone in amounts of 0.01 to 0.05 ppm of air is allowable in comfort air conditioning. Above this limit there is a pungent, unpleasant odor and perhaps respiratory distress, depression, and stupor.6 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. Cer tain dusts may be very harmful, but coal dust is tolerated wejl. The effects of various industrial dusts, pollens, etc., are discussed in Chapter 8. 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 7). While in some instances it may be possible to reduce the physical im purities of the air by dilution from a non-contaminated source, such a source is rarely available. Frequently, outside air contains a higher con centration of physical impurities than indoor air. Therefore, it is usually desirable to reduce the concentration of physical impurities by air clean ing methods. (See Chapter 34.) THERMAL INTERCHANGES WITH ENVIRONMENT Body temperature depends upon the balance between heat production and heat loss. Heat resulting from oxidation in the body (metabolism) CHAPTER 6 maintains the body temperature well above that of the surrounding air in a cool or cold environment. At the same time, heat is constantly lost from the body by radiation, convection and evaporation. Since, under ordinary conditions, the body temperature is -maintained at its normal level of about 98.6~F,-the heat, production must be balanced by the heat loss. During work, the body temperature may rise; in fact, afternoon tem peratures of normal persons average 1 deg above the resting value of the morning whether working or not. The fundamental thermodynamic processes concerned in heat inter changes between the body and its environment may be described by the equation: jq=S + ERC (1) where 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 heat loss or gain. The rate of metabolism, M, is always positive. The storage, S, may be either positive or negative, depending upon whether 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 negative when it is below. DuBois,7 after careful calorimeter studies on a fasting, nude man, plotted the partition of body heat loss and heat production as a function of tem perature. Fig. 1 shows some disparity 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 has to take no particular action to maintain its heat balance. If he is clothed, or if he is active, this point will naturally he 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 something 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 subjacent 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 tempera ture 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 production by increasing muscular tension, by shivering, or by spontaneous increase in activity.8 As long as these are adequate 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 he in the zone of metabolic regulation against cold. Beyond Physiological Principles 115 this point, the body enters the zone of inevitable body cooling. Once body temperature starts to fall, man is headed for disaster. It will be seen that, in man, deep body temperature is preserved over an important range of cold external conditions, at the expense of (1) a fall in the temperature of the peripheral tissues, and (2) an increased expendi ture 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 side of the neutral point, there exists a zone of vaso-motor regulation against heal, corresponding to that against cold. The blood flow through the skin is increased when the opportunities for heat loss to the environment are restricted.8 This increase in blood'flow may double the conductance 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 Fig. 1. Heat Loss fbom Human Being bt Evapobation, Radiation, and Convection* * Normal control, naked, in calorimeter at temperatures from 72.8 to 94.1 F. First column in tech expertment represents heat production as determined by indirect calorimetry, the second column, heat elimination. The portion marked with vertical lines represents vaporisation; the dotted area, convection; tbe unmarked area, radiation. The skin temperature represents the average reading of 18 spots on the surface. unable to balance tbe 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 side, is a new and power ful method of promoting heat loss--the provision of water, by the operation of the sweat glands, for evaporative cooling. As long as evaporation is adequate to restore the desired heat loss, the body is in the zone of evapora tive regulation against heat. When this ceases to be adequate, the body is (o the zone of inevitable body heating. The body enjoys a little more latitude lrj this zone than it did in the corresponding zone on the cold side, 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 regu lation in the zone of evaporative regulation. Atmospheric vapor pressure 116 CHAPTER 6 1954 Guide and air motion are most important. With dry-bulb temperature above body temperature, air motion facilitates evaporative heat loss by removing hot humid air from contact with the skin and replacing it with relatively drier air. .- Heat regulation in man requires an intact set of sensory nerves, a nor mal sympathetic nerve supply to sweat glands and blood vessels, a great -many sweat glands, and a circulatory 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 graphi cally in Fig. 2. The dotted curves, from a study at the John B. Pierce Laboratory of Hygiene,10 are for subjects lightly clothed in a semi-reclining position, and give the relation between the dry-bulb temperature of the environment (with about 45 percent relative humidity) and the metabolic I f ORY-BUIB TEMPERATURE. DEG FAHR (AT A5 PER CENT RELATIVE HUMIDITY) Fig. 2. Relation Between Metabolism, Storage, Evaporation, Radiation Plus Convection, and Temperature for the Clothed Subject rate (heat production), the rate of heat dissipation by radiation and con- t vection 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 A.S.H.V.E. Research Laboratory11 give the same relationships for ? healthy, male subjects (18 to 24 years of age), seated at rest and dressed f in customary winter indoor clothing. The Pierce Laboratory data for \ the semi-reclining subjects also include the rate of heat storage (either fs 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 IJ of the radiation, convection and evaporative losses). Here, storage is given by the difference between the metabolism and total heat loss. % The small difference between the metabolic rates for the two groups of subjects may be accounted for by difference in activity. Heat exchange f between the body and the environment by radiation and convection is | greater for' the lightly clothed subject, both for cool conditions where | there is excessive heat loss, and for very warm conditions where there is .j transfer of heat from the atmosphere to the body. The two curves for . Physiological Principles 117 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 subject, and below 85 F for the lightly clothed sub ject, evaporation loss is minimal and constant. Burch12 has shown that this insensible perspiration reflects the permeability of the skin to the moisture of the body. Above these temperatures, control 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 zone of evaporative heat regulation, air movement facilitates heat loss if the temperature of the air is not above that of the,skin.10 Under hot, dry conditions air movement may be of little advantage, or even of disadvantage, if it increases the addition of heat to the skin by conduction more than it promotes the loss of heat from the skin by evaporation. Table 2. Physiological Responses to Heat of Men at Rest and at Work* ErrrcriTB Temp 60 70 80 85 90 95 100 105 110 AtTULL Chess Temp (Fahr Deg) 96.1 96.6 97.0 97.6 99.6 104.7 Men at Rest Men at Wore 90,000 ft-lb op Work per Hour Rise in Rectal Temp (Fahr Deg per Hr) Increase in Pulse Approximate Lees in Body Rate Weight by (Beats per Perspiration Min per (Lb per Hr) Hr) Total Work Accomplished (Ft-Lb) Rise in Body Temp (Fahr Deg per Hr) Increase in Pulse Rate (Beats per Min per Hr) Approximate Loss in Body Wt by Per spiration (Lb per Hr) 0.0 0.0 0.1 0.3 0.9 2.2 4.0 5.9b 0 0 1 4 15 40 S3 137b 6.2 0.3 0.4 0.5 0.9 1.7 2.7 4.0b 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 4.0b 6.0b 8.5b 6 7 11 17 31 61 103b 158b 237b ^TTPuted value from exposures lasting less than one hour. ________ w ava'j . Studies at the A.S.H.V.E. Research Laboratory14 and elsewhere 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 envi ronments results in physiological derangement affecting the leucocyte count of the blood, and other factors dealing with man's mechanism of defense against infection. Wherever S (Equation 1) becomes strongly positive and body tem perature rises progressively, men will continue to work until body tempera ture 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 in which the venous return to the heart is reduced so that fainting results.15 Early symptoms of heat exhaustion may include fatigue, headache, dizziness when erect, loss of appetite, nausea, abdominal distress, vomiting, shortness of breath, flush ing of face and heck, pulse rate above 150,' glazed eyes, and mental dis- 118 CHAPTER 6 1954 Guide Table 3. Uppeb Limits op Environmental Conditions for Acclimatized, Healthy, Young Men in Military Service Environment Reactions at the end of 4 hb Rectal Temp F Pulse rate l: Relatively Easy.............................. Difficult................................ .............. Impossible........................................ Below 101 101 to 102 Above 102 Below 130 130 to 145 Over 145 turbances 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 abdo men 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 administration 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 required to reduce the excessive body temperature by cooling quickly to avoid irreparable damage to the brain.1' The deleterious physiologic effects of high temperatures exert a power ful influence upon physical activity, accidents, sickness and mortality. Both laboratory and field data show that physical work in warm atmos pheres is a great effort, and that production falls progressively as the temperature rises. >, ACCLIMATIZATION V 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 pres sure than when unacclimatized. The process of acclimatization requires | work in the heat.17 During the recent war, white troops lived and did hard physical work for long periods in tropical conditions when disease hazards were controlled. In recent tests made at the A.S.H.V.E. Research Laboratory,18 subjects were required to perform light work under very hot conditions for a 4-hr U period each day. It was found that the ability of a new subject to endure |s these conditions' showed daily improvement for a period of at least 2 weeks. |f However, after acclimatization was completed, a recess of several days | had no effect on the endurance of the subject. Individuals differ widely ig in their capacity to acclimatize. Acclimatized men lose most of these Simprovements in a few weeks of temperate climate, even though they are f; vigorously active. In the course of acclimatization, the sweat glands come l'- to secrete fluid less rich in salt.19 For all except those carrying out really hard work in hot, dry atmospheres, this effects an important saving in Physiological Principles 119 Fig. 3. Heat Endurance of Acclimatized Subjects Working at a Specific Rate*0 salt loss, and makes all the difference between 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 the 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 that 88 F wet-bulb was the limit of endurance for coal miners, and later observers have concurred. A study was made at the Armored Medical Research Laboratory20 to determine the upper limits of environmental conditions under which a man can perform certain work. Thirteen enlisted men, thoroughly accli matized to the hot conditions, served as subjects. . During each test, the subjects were required to march for 4 hr at the rate of 3 mph, carrying 120 1954 Guide5 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. In some hot industries where few workers are Physiological Principles 121 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 conditions in which, the , MRT was kept about 40 F deg higher than 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. the 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 com/pared 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 diminishing importance of unit rise in MRT. Under ordinary still air conditions the effects of air temperature and MRT appear to be interdependent. Various authorities give 0.3 to 1 deg increase of room temperature to compensate for 1 deg depression of the MRT. Si ill! ' Fio. 5. Relation Between Total Heat Loss from the Human Body and Effec tive Temperature for Still Air* 14 * Curve A--Persons working, metabolic rate 1310 Btu per hour. Curve B--Persons working, metabolic rate 850 Btu per hour. Curve C--Persons working, metabolic rate 660 Btu per hour. Curve D--Persona seated at rest, metabolic rate of 400 Btu per hour. Curves B and D based on test data covering a wide tem perature range. Curves A and C based on test data at an Effective Temperature of 70 and extrapolation of Curves B and D. AU curves are averages of values for high and low relative humidities; variation due to humidity is * engaged in large spaces the worker himself, rather than the atmosphere, can 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.21 The A.S.H.V.E. Laboratory has studied the effects of walls of higher temperature than the air.18 The findings are in part shown in Fig. 4. It will be seen that the importance of mean radiant temperature, as com pared with that of the effective temperature, decreases as the effective temperature rises; and also, to a certain extent, as the mean radiant tem perature 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 f> aww wnvisuiUN .LiOSS FROM Body and Dry-Bulb Temperature for Still Air* 14 * See footnote a, Fig. 5. _ . w j. i via CONDITIONING PROBLEMS J V AliV 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 sur face 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 increases iu certain diseases and in the presence of fever. The metabolic rate is some what lower in women. Heat production goes up sharply with work and varies widely in different persons doing the same work. Figs. 5, 6, and 7 and Table 25 of Chapter 13 give sufficient basic data for estimating heat pro duction and heat loss under various conditions. 122 CHAPTER 6 1954 Guide EFFECTIVE TEMPERATURE INDEX AND COMFORT ZONES There is no precise physiologic observation by which comfort can be evaluated. Mean skin temperature offers some 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 temperature 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 radiation effects. Dry air at a relatively high tem perature may feel cooler than air of lower temperature with a high moisture content. Air motion makes any moderate condition feel cooler. Radia tion to cold or from warm surfaces is another important factor under certain conditions affecting the comfort reaction of the individual. Pio. 7. Evaporative Heat and Moisture Loss prom the Human Bodt in Rela- non to Dry-Bulb Temperature for Still Air Conditions* 14 * See footnote a, Fig. 5. - . Combinations of temperature, humidity, and air movement which in duce the same feeling of warmth are called thermo-equivalent condi tions. A series of studies at the A.S.H.V.E. Research Laboratory estab lished the equivalent conditions for practical use. This scale of thermo equivalent conditions not only indicates the sensation of warmth, but alk) 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 conditions is fixed by ' the temperature of slowly moving (15 to 25 fpm air movement) saturated Physiological Principles 123 air which induces a like sensation of warmth or cold. Thus, any air con dition has an effective temperature of 60 deg when it induces a sensa tion 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 dry- and 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, e.g. 1939. Fig. 9 is another form of effective temperature chart embodying all three variables: dry-bulb and wet-bulb temperatures, and air velocity. Table 4. Comparison op Comfort Ranges With Zone op Thermal Neutrality Investigators Effective Temperatube Opebative Temp Optimum Line Range _ Range Remabks Comfort Zone Houghten and Yaglou. 66 Yaglou and Drinker... Yaglou........ Keeton et al 71 72.5 75 63-71 66-75 fi6-R2 74-76 Winter non-basal; at rest, nor mally clothed. Men and women. Summer non-basal; at rest and normally 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. Zone of Thermal Neutrality DuBoia and Hardy.... Winslow, Herrington and Gagge 75 71.8 73.2-76.9 64.8-76.0 Basal; nude; men; Basal; clothed; men. 84.0-87.8 Non-basal; at rest; nude; men. 74 -84 Non-basal ;at rest ;clothed ;men. ___^.vuuuuij, cucu/ivc tempera,ulire It) an H1Q6X OI tH6. Cl6^rG6 ot wrarmth experienced by the body. An effective temperature line is, there fore, a line defining the various combinations 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. . Tests14 made at the A.S.H.V.E. Research Laboratory in very hot con ditions, with subjects doing light work, were in very close agreement with the effective temperature chart. Other work20 under similar environ mental conditions, but with subjects walking 3 mph and carrying 20 lb packs, indicated that the effective temperature lines should be more 124 CHAPTER 6 1954 Guide % nearly horizontal. It therefore appears that- the slope of the ET lines may vary, depending upon the rate of work being performed. Fig. 10 shows the A.S.H.V.E. Comfort Chart22 modified in several respects from the chart previously shown. The former areas and arrows indicating the summer and whiter comfort zones have been removed. 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. Physiological Principles 125 GRAINS OF MOISTURE PER POUND OF DRY AIR The distribution curve, showing the percent of people feeling comfortable 0 at various effective, temperatures in summer, 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 f percent of people feeling comfortable at various effective temperatures in k the winter, was based on research prior to 1932. This curve indicated C that at 66 ET a maximum number of people were comfortable. Later jy studies21 by the A.S.H.V.E. Research Laboratory indicated that a maxi- g mum of 97.7 percent of the people were comfortable at 68 ET, and this |finding has been confirmed by current practice.24 However, adequate data from the later studies were available only for the ET range of 65 to 69, |' Fig. 9. Effective Temperature Chart Showing Normal Scale of Effective Temperature, Applicable to Inhabitants of the United States Under Following Conditions: ,, X. Clothing; Customary indoor clothing. B. Activity: Sedentary or light muscular work. C. Heating Methods: Convection type, t.c,, warm air, direct steam or not water radiators, plenum systems. 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. Radiation from occupants to room surfaces, and between the occupants, has an important bearing on the feeling of warmth, and may alter to some 126 ( CHAPTER 6 1954 Guide f ' .. measurable degree the optimum 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 imbedded in the walls, these factors must be -f fi % Physiological Principles 127 Many field studies23 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 manage ments of offices employing large numbers of workers (Fig. 11). On the whole, women of all age groups studied prefer an effective temperature for comfort, 1.0 deg higher than men. All men and women over 40 years of age prefer a temperature 1 deg ET higher than that desired by persons below this age. The persons serving in all of these studies were repre sentative of office workers dressed for air conditioned spaces in the summer season, and engaged in the customary office activity. Fig. 10. A.S H.V.E. Comfort Chart for Still Air'-*1 * Note.--Both summer and winter comfort lines apply to inhabitants of the United States only. Applica tion of winter comfort line is further limited to rooms heated by central systems of the convection type. The line does not apply to rooms heated by radiant methods. Application of summer comfort line is limited to homes, offices and the like, where the occupants become fully adapted to the artificial air conditions. The line does not apply to theaters, department stores, and the like where the exposure is less than 3 hours. The' summer comfort line shown pertains to Pittsburgh and to other cities in the northern portion of the United States and Southern Canada, and at elevations not in excess of 1000 ft above sea level. An increase of one deg ET should be made approximately per 5 deg reduction in north latitude. b Dotted portion of winter comfort line was extrapolated beyond test data. . compensated. Likewise, in densely occupied spaces, such as classrooms, p theaters and auditoriums, temperatures somewhat lower than those indicated by the comfort line may be desirable because of counter- f, radiation between the bodies of occupants in close proximity to each other, f Such radiation will also elevate the mean radiant temperature of the room. ' | Pig. 11. Relation Between Effective Temperature and Percentage Observa tions Indicating Comfort On the basis of present knowledge, for different geographical 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, variations in sensa tion of comfort among individuals may be greater for any given location than variations due to a difference in geographical location. The available information indicates that changes in weather conditions over a period of a few days do not alter the optimum indoor temperature. Sudden chilling (shock) of persons entering a cooled and air conditioned space during the summer months, may at times be important. It is due to the rapid evaporation of perspiration which accumulated on the skin and in the clothing during previous subjection to hot and humid outside conditions. While studies26 have shown that for healthy individuals this shock is not harmful, under some conditions it may be unpleasant or ref'".' 128 CHAPTER 6 1954 Guide even harmful. People entering and remaining in cooled spaces for short periods, 15 min or less, may be satisfied with less cooling. For long occupancy very little deviation from the optimum effective temperature is indicated. An exit shock upon re-entering a warm atmosphere is equally plausible. Experiments at the A.S.H.V.E. Research Laboratory2* indicated no demonstrable harm to a healthy individual. Adaptation occurred as soon as normal perspiration was established. Mild exercise shortened the adaptation time. A great number of persons seem to be fairly content in summer with a higher plane of indoor temperature. Studies by the University of Illi nois27 in cooperation with the A.S.H.V.E. Committee on Research indi-. cate that effective temperatures as high as 74.5 ET are acceptable in the living quarters of a residence, and while this condition is not representa tive of optimum comfort, it provides sufficient relief in hot weather to be acceptable to the majority of users, in the interest of economy. Individual minority differences can be counteracted by clothing. Satisfactory comfort conditions for persons at work28 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 neces- . sary for comfort. Clothing has been evaluated for its overall insulation effects by a physical unit, the clo which equals 0.116 C deg per (kilogram . calorie) (square meter) (hour).29 Yaglou30 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 born infants, the optimum temperature varies from 100 to 75 F, depending upon the stage of development. The optimum relative humidity for these infants is placed at 65 percent.31 No data are yet available on the optimum 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. For children (having high metabolism) at school, in winter clothes, 70 F has been considered correct, with 55 F recommended for gymnasiums. REFERENCE 1 Code of Minimum Requirements for Comfort Air Conditioning (A.S.H.V.E. Transactions, Vol. 44, 1938, p. 27). * A.S.H.V.E. Research Report No. 1031--Ventilation Requirements, by C. P. . Yaglou, E. C. Riley and D. J. Coggins (A.S.H.V.E. Transactions, Vol. 42, 1936, ' P- 133)- . . . . .; 3 A.S.H.V.E. Research Report No. 959--Indices of Air Change and Air Distribu tion, by F. C. Houghten and J. L. Blackshaw (A.S.H.V.E. Transactions, Vol. 39, 1933, p. 261) * Tobacco Smoke Control--A Preliminary Study, by Charles S. Leopold (A.S.H.V.E. Transactions, Vol. 51, 1945, p. 255). '.. 3 A.S.H.V.E. Research Report No. 921--Changes in Ionic Content in Occupied Rooms Ventilated by Natural and Mechanical Methods, by C. P. Yaglou, L. C. Benjamin and S. P. Choate (A.S.H.V.E. Transactions, Vol. 38, 1932, p. 191). A.S.H.V.E. Research Report No. 965--Physiologic Changes During Exposure to Ionized Air, by C. P Yaglou, A. D. Brandt and L. C. Benjamin (A.S.H.V.E. Trans actions, Vol. 39,1933, p. 357). A.S.H.V.E. Research Report No. 985--Diurnal and Seasonal Variations in the Small Ion Content of Outdoor and Indoor Air, by C. P. Yaglou and L. C. Benjamin (A.S.H.V.E. Transactions, Vol. 40, 1934^p. 271). The -. ` Physiological Principles 129 Nature of Ions in Air and Their Possible Physiological Effects, by L. B. Loeb (A.S.H.V.E. Transactions, Vol. 41, 1935, p. 101). The Influence of Ionized Air Upon Normal Subjects, by L. P. Herrington (Journal Clinical Investigation, 14, January, 1935). The Effect of High'Concentration of Light Negative Atmospheric Ions on the Growth and Activity of the Albino Rat, by L. P. Herrington and Karl L. Smith (Journal Industrial Hygiene., 17, November, 1935). Subjective Reactions of Human Beings to Certain Outdoor Atmospheric Conditions, by C.-E. A. Winslow and L. P. Herrington (A.S.H.V.E. Transactions, Vol. 42, 1936, p. 119). * The British Medical Journal, Editorial, June 25, 1932, p. 1182. 7 The Mechanism of Heat Loss and Temperature Regulation, by Eugene F. DuBois (Lane Medical Lectures, Stanford University Publications, Medical Science, Vol. 3, 1937, No. 4, p. 348; also Transactions of the Association of American Physicians. Vol. 51, 1936, p. 252). 8 Exchanges of Heat and Tolerance to Cold in Men Exposed to Outdoor Weather, by E. J. Adolph and G. W. Molnar (American Journal of Physiology, Vol. 146. 1946. p. 507). ' 'A.S.H.V.E. Research Report No. 1108--Cardiac Output, Peripheral Blood Flow and Blood Volume Changes in Normal Individuals Subjected to Varying Envi ronmental Temperatures, by F. K. Hick, R. W. Keeton, N. Glickman and H. C. Wall (A.S.H.V.E. Transactions, Vol. 45, 1939, p. 123). `"A.S.H.V.E. Research Report No. 1107--Recent Advances in Physiological Knowledge and Their Bearing on Ventilation Practice, by C.-E. A. Winslow, T. Bed ford, E. F. Dubois, R. W. Keeton, A. Missenard, R. R. Sayers and C. Tasker (A.S.H.V.E. Transactions, Vol. 45, 1939, p. 111). " A.S.H.V.E. Research Report No. 830--Heat and Moisture Losses from the Human Body and Their Relation to Air Conditioning Problems, by F. C. Houghten, W. W. Teague, W. E. Miller and W. P. Yant (A.S.H.V.E. Transactions, Vol. 35 1929, p. 245). 13 Rate of Insensible Perspiration (Diffusion of Water) Locally Through Living and Through Dead Human Skin, by G. E. Burch and T. Winsor (Archives of Internal Medicine, Vol. 74, 1944, p. 437). 13 The Influence of Clothing, Work and Air Movement on the Thermal Exchanges of Acclimatized Men in Various Hot Environments, by N. A. Nelson, W. B. Shelly, S. M..Horvath, L. W. Eichna, and F. F. Hatch (Journal of Clinical Investigations. Vol. 27, 1948, p. 209). "A.S.H.V.E. Research Report No. 654--Some Physiological Reactions to High Temperatures and Humidities, by W. J. McConnell and F. C. Houghten (A.S.H.V.E. Transactions, Vol. 29, 1923, p. 129). A.S.H.V.E. Research Report No. 672-- Further Study of Physiological Reactions, by W. J. McConnell, F. C. Houghten and F. M. Phillips (A.S.H.V.E. Transactions, Vol. 29, 1923, p. 353). A.S.H.V.E. Re search Report No. 690--Air Motion, High Temperatures and Various Humidities-- Reactions on Human Beings, by W. J. McConnell, F. C. Houghten and C. P. Yag lou (A.S.H.V.E. Transactions, Vol. 30, 1924, p. 167). A.S.H.V.E. Research Re port No. 718--Work Tests Conducted in Atmospheres of High Temperatures and Various Humidities in Still and Moving Air, by W. J. McConnell and C. P. Yaglou (A.S.H.V.E. Transactions, Vol. 31, 1925, p. 101). A.S.H.V.E. Research Report. No. 719--Basal Metabolism Before and After Exposure to High Temperatures and Various Humidities, by W. J. McConnell, C. P. Yaglou and W. B. Fulton (A.S.H.V.E. transactions, Vol. 31, 1925, p. 123). A.S.H.V.E. Research Report No. 908-- Heat and Moisture.Losses from Men at Work and Application to Air Conditioning fjoblems, by F. C. Houghten, W. W. Teague, W. E. Miller and W. P. Yant (A.S.H.V.E. Transactions, Vol. 37, 1931, p. 541). A.S.H.V.E. Research Report No. 1106--Air Conditioning in Industry--Physiological Reactions of Individual Workers to High Effective Temperatures, by W. L. Fleisher, A. E. Stacey, Jr., F. C. '"-ghlcn and M. B. Ferderber (A.S.H.V.E. Transactions, Vol. 45, 1939, p. .59). A.S.H.V.E. Research Report No. 1153--Seasonal Variation in Reactions to Hot Atmospheres, by F. C. Houghten, A. A. Rosenberg and M. B. Ferderber (A.S.H.V.E. Transactions, Vol. 46, 1940, p. 185). Is A.S.H.V.E. Research Report No. 1151--The Peripheral Type of Circulatory PaHure in Experimental Heat Exhaustion, by R. W. Keeton, F. K. Hick, Nathaniel 'jiickman and M. M. Montgomery (A.S.H.V.E. Transactions, Vol. 46, 1940, p. 157). " Heat Disease: Clinical and Laboratory Studies, by M. W. Heilman and E. S. ontgomery (Journal of Industrial Disease and Toxicology, 18:651, 1936). ' 7 Performance in Relation to Environmental Temperature, by I., W. Eichna, 1945 p 2^5r^58), ^ Ashe and N. Nelson (Bulletin of Johns Hopkins Hospital, Vol. 76, 130 CHAPTER 6 1954 Guide '* Physiological Response of Subjects Exposed to High Effective Temperatures and Elevated Mean Radiant Temperatures, by C. M. Humphreys, Oscar Imalis and Carl Gutberlet (A.S.H.V.E. Transactions, Vol. 52, 1946, p. 153). 19 Life, Heat and Altitude, by David B. Dill (Harvard University Press, Cam bridge, 1938). . . 19 The Upper Limits of Environmental Heat and Humidity Tolerated by Accli matised Men, Working in Hot Environments, by Ludwig W. Eichna, William F. Ashe, . William B. Bean and Walter B, Shelley (The Journal of Industrial Hygiene and Toxi CHAPTER 7 AIR CONDITIONING IN THE PREVENTION AND TREATMENT OF DISEASE cology, Vol. 27, March, 1945, p. 59). 91 A.S.H.V.E. Research Report No. 1188--Local Cooling of Workers in Hot Industry, by F. C. Houghten, M. B. Ferderber and Carl Gutberlet (A.S.H.V.E. Transactions, Vol. 47,1941, p. 403). 32 A.S.H.V.E. Research Report No. 673--Determination of the Comfort Zone, by F. C. Houghten and C. P. Yaglou (A.S.H.V.E. Transactions, Vol. 29, 1923, p. 361). A.S.H.V.E. Research Report No. 691--Cooling Effect on Human Beings Produced by Various Air Velocities, by F. C. Houghten and C. P. Yaglou (A.S.H.V.E. Trans actions, Vol. 30, 1924, p. 193). A.S.H.V.E. Research Report No. 717--Effective Temperature with Clothing, by C. P. Yaglou and W. E. Miller (A.S.H.V.E. Trans actions, Vol. 31, 1925, p. 89). A.S.H.V.E. Research Report No. 755--Effective Temperature for Persons Lightly Clothed and Working in Still Air, by F. C. Hough ten, W. W. Teague and W. E. Miller (A.S.H.V.E. Transactions, Vol. 32,1928, p. 315). How to Use the Effective Temperature Index and Comfort Charts, by C. P. Yaglou, 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 THE Second World War caused an increase of interest in the preventive aspects of air conditioning. It re-emphasized the importance of the control of airborne infection and demonstrated the value of air cooling under tropical conditions for the prevention of heat rash, for promoting proper rest and sleep, and in the convalescence of patients. The problem of air conditioning or air purification in shelters, hospitals, W. H. Carrier, Dr. E. V. Hill, F. C. Houghten and J. H. Walker (A.S.H.V.E. Trans or any buildings, following an atomic explosion has the attention of engi actions, Vol. 38, 1932, p. 410). 93 A.S.H.V.E. Research Report No. 1196--Comfort with Summer Air Condition ing, by 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 (A.S.H.V.E. Transactions, Vol. 48, 1942, p. 107). 94 Conditions for Comfort, by C. S. Leopold (A.S.H.V.E. Transactions, Vol. neers, military personnel, public health authorities, private physicians, and the general public. The type and structure of shelters are important. In strategic areas likely to be bombed, they should be windowless, under ground, strong enough to resist blast and have sufficient cover to protect against initial radiation. Suitable ventilation is a necessity, and could be 53, 1947, p. 295). " A.S.H.V.E. Research Report No. 1102--Shock Experiences of 275 Workers After Entering and Leaving Cooled and Air Conditioned Offices, by A. B. Newton, F. C. Houghten, Carl Gutberlet, R. W. Qualley and M. C. W. Tomlinson (A.S.H.V.E. Transactions, Vol. 44,1938, p. 571). Physiologic Adjustments of Human Beings to Sudden Change in Environment, by N. Glickman, T. Inouye, S. E. Telser, R. W. provided by the use of pressurized installation in which any air taken from the outside is forced through a ventilator. Air conditioning and heating or cooling systems could then be kept in continuous operation for improv ing inside air conditions and controlling room temperature. Heat trans mission through the walls, carbon dioxide accumulation, and the total 'r Keeton, F. K. Hick and M. K. Fahnestock (A.S.H.V.E. Transactions, Vol. 53, number of people using the shelter, are factors in determining the neces i. 194"7,Ap.S. .3H27.V)..E. Research Report No. 1055--Cooling Requirements for Summer Comfort Air Conditioning, by F. C. Houghten, F. E. Giesecke, C. Tasker and Carl sity for using outside air. Such a shelter should be closed to outside air during the period immediately following a blast. Gutberlet (A.S.H.V.E. Transactions, Vol. 43, 1937, p, 145). A surface or subsurface atomic burst would result in wide dispersion of 97 A.S.H.V.E. Research Report No. 1012--Study of Summer Cooling in the Re radio-active particles in high concentrations.1 There is relatively little search Residence for the Summer of 1934, by A. P. Kratz, S. Konzo, M. K. Fahne stock and E. L. Broderick (A.S.H.V.E. Transactions, Vol. 41, 1935, p. 207). 98 A.S.H.V.E. Research Report No. 755--Effective Temperature for Persons Lightly Clothed and Working in Still Air, by F. C. Houghten, W. W. Teague and W. E. Miller (A.S.H.V.E. Transactions, Vol. 32, 1926, p.. 315). 99 A Practical System of Units for the Description of the Heat Exchange of Man with His Environment, by A. P. Gagge, A. C. Burton, and H. C. Gazett (Science, danger from such particles after a high atomic burst. Windows in ordi nary buildings close to the blast would be broken, and consequently, air conditioning systems would provide no protection against this hazard. At a distance of 1200 ft from ground zero, many windows would not be broken; outside leakage would therefore be slight, and air conditioning systems could be used with advantage. Vol. 94, 1941, p. 428). 99 Thermal Insulation of Clothing, by C. P. Yaglou (A.S.H.V.E. Transactions, Vo9l1. A54p,p1l9ic4a8,tiop.n2o9f1)A. ir Conditioning to Premature Nurseries in Hospitals, by C. P. Yaglou, Philip Drinker and K. D. Blacktgn (A.S.H.V.E. Transactions, Vol. 36, 1930, p. 383). The smog incident in Donora, Pa., has focused the attention of health authorities and engineers on the problem of air contamination by toxic gases. The exact way in which such substances affect the human being is unknown.2 There has been a great deal of speculation, but in reality there is little specific information concerning this problem. It is believed that in such cases the combination of contaminants, rather than any single substance, produces the toxic effects. It is known that low atmospheric pressure, with accumulation of toxic substances in increasingly higher concentration, produced the condition in Donora. TheU. S. Public Health team, in their investigation, found that this same city had experienced several previous incidences of lesser severity during the preceding 30 years, ihis was shown by much higher mortality rates during certain periods. A high percentage of the population of this city suffered to some extent 131 132 CHAPTER 7 1954 Guide during the recent smog. Older individuals were more seriously affected with cardio-respiratory symptoms. Study of such a situation is rather difficult, as explained in the afore mentioned report. The medical profession has much to learn about the effects of these substances on human beings, and until more precise knowl edge is obtained, it is difficult to know when precise controls are really --needed. Further research is urgently needed.3 : ; SANITARY VENTILATION During the last 15 years great popular interest has been aroused in the spread of respiratory infection indoors, and control by ventilation or its sanitary equivalent by air disinfection. In Europe three important docu ments have appeared recently in English, Swedish, and French literature.4'5'6 : In the United States where the study began, the vast literature has been consolidated, and definitions, formulations, and factors of sanitary ventila tion 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.7'8'9'10 The work of a Technical Advisory Committee on Air Sterilization of the A.S.H.V.E. has j from time to time since 1944 reported progress in The Journal, and has f recommended a set of definitions, formulations and factors for joint adop- y tion by the American Public Health Association and the Society. , But this important new field of sanitary ventilation is just emerging 5 from the research to the development stage. When consolidation and cod- f ification of present data have been completed, a more comprehensive treatment in The Guide may be possible. The following section on . Control of Airborne Infection gives some idea of the scope of the subject. CONTROL OF AIRBORNE INFECTION !. The majority of airborne diseases are spread indoors where people gather. Any program of air sanitation is influenced by a number of factors. In the winter months, the closing of doors, windows and other means of access f to the outside air to conserve warmth, as well as the crowding of persons * indoors, provides conditions conducive to a high incidence of contagion; y, This seasonal phenomenon, illustrated in Fig. 1 which represents a study made by the U. S. Public Health Service, will concern the ventilating engineer insofar as air quality (determined by temperature, humidity, air replenishment and type of air movement and by freedom from contamina- fj tion) is a major intrinsic factor. Apart from the seasonal picture of air- f borne contagion, are such extrinsic factors as rate of turnover of personnel, and the marked susceptibility of the recruit in comparison with permanent j| personnel11 as shown in Fig. 2 by studies of military personnel housed infg barracks. These extraneous variables and the factor of contact infection gy (direct spray) tend to complicate any evaluation of the effectiveness of|;air sanitation for elimination of micro-organisms in droplet-nuclei and dropr>. let-dust. Thus, control measures may eliminate consistently 90 percent. of airborne organisms in laboratory tests, but cannot effect a decrease in f actual incidence of infection exceeding 30 percent. Thirty percent mayjS be the maximal reduction in infection possible by air treatment methods'.j| Air Conditioning in Prevention and Treatment of Disease 133 The distinction should be clearly drawn, therefore, between the'effective ness of a procedure in laboratory tests 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 im portant than direct inhalation of infectious droplets or droplet nuclei in the spread of respiratory tract infections.12 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; (b) rapid venting or settling of these particles so that those remaining airborne are in low con- Occurrence of causing disability for 8 consecutive days or longer in. a group of 100,000 wage earners (10 percent women) in different industries. _ , * Graph obtained from Dean K. Brundage, U 8. Public Health Service. Pic. 1. Study op Average Monthly Fbequency (1921-1926 inclusive) op Sfecipied Respiratory Diseases* centration; (c) survival of infective particles to permit the accumulation of high concentrations on surfaces; (d) repeated reintroduction of infective particles into the air under the stimulus of ward activities or by air currents of the order of 50 fpm over the floor; and (e) extension of infective areas by air turbulence throughout the ward or hospital. The most important link in this probable infection chain has been demonstrated to be the reintro duction of particles into the air.13 ' Intensive studies on air disinfection have indicated two distinct control measures: (a) suppression of dust and lint, and (6) disinfection of dropletnuclei. A third measure, control 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 relative humidity. The mortality rate of the organisms is very high at a relative humidity of 5.9 percent,14 and decreases at humidities above and below this figure. It m$ 134 CHAPTER 7 1954 Guide ;i has also been reported that the influenza virus loses much of its virulence when the relative humidity is 50 percent.16 Well controlled, large scale tests of the various methods of air sterilization conducted in barracks16;17 have confirmed 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 baeteriologic studies aboard ships. Treatment of floors and bedclothes with oil emulsions has proved effec tive in reducing bacterial dispersion by as much as 90 percent in Army barracks and station hospitals.17 The incidence of acute respiratory in fections was from 10 to 30 percent lower in barracks with oiled floors and bedclothes than it was in control barracks which received no special treat ment. More recent studies, however, have yielded inconsistent results. An emulsifying mixture, Fixanol C containing cetyl pyridinium bromide, when incorporated in the oil-in-water emulsion imparted a bactericidal action to the emulsion. Blankets treated with this substance and oil 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.12 No simple method for disinfecting droplet-nuclei has yet been devised. Under favorable laboratory conditions, propylene glycol in concentrations of 0.07 to 0.14 milligrams per liter, and triethylene glycol in a concentra tion 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.18-u-20 A humidity of 50 percent, without the use of glycol vapor, has been reported as destructive to some bacteria. However, maxi mum rates of bactericidal action of triethylene glycol vapor will be secured at humidities between 20 to 50 percent.21 In a recent report on the effect of triethylene glycol vapor in air dis infection, it is pointed out that the rate of ventilation, as determined by the number of air changes per hour, is important and that continuous- va porization is needed to maintain effective concentrations of glycol vapor.21 Air Conditioning in Prevention and Treatment of Disease 135 In the. absence of an apparatus to measure the concentration of vapor in the room, a slight fog is an indication of adequate concentration. Ab sence of such a fog indicates a non-bactericidal concentration. The report stated: "However, under experimental- conditions we have observed no apparent decomposition of triethylene glycol when temperatures up to 290 F were maintained at the site 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 ture 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 a given vaporizer be capable of various outputs as measured by grams of liquid glycol vaporized per hour; for instance, from 0.5 g to at least 2.0 g per 1000 cu ft of volume treated, for small vaporizing 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 40QO cu ft. Apparatus for the production of glycol vapor, and an independent duct system for carrying this vapor and dilut ing air for large rooms or spaces, and unit type vaporizers for small spaces, have been described recently.22 There is also available a device for the automatic regulation of glycol vapor in the air called the glycostat. This instrument has been calibrated to measure the degrees of saturation of the air with glycol vapor by direct reading of the variations in the intensity of light reflected from the glycol condensing surface of the wheel of the instrument.23 . Under practical conditions, particularly in the presence of dust in the air, glycol effectiveness is much reduced. The use of other chemical areosols that have been tried is limited by their toxicity, odor, or destructive ness 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 incidence rate of minor respira tory infections.24 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 radiation--2537 Angstrom Units, 1 to 7 ergs per (cm2) (sec) at bed level-- than they were in adjacent control barracks without ultraviolet radiation.26 A controlled study over a six-year period on the evaluation of ultraviolet radiation of sleeping quarters as a supplement of accepted methods of respiratory disease control was recently reported.26 The amount of ra diation over the last two years of the period was believed to be about five times that recommended commercially: No significant effect in the incidence of disease could be detected in about 400 inmates during the sixyearperiod. This conclusion may not be applicable to present ultraviolet equipment installed in accordance with manufacturers' recommendations. 4he data imply that air layers were not sufficiently mixed. However, more efficient mixing would have been obtained at the expense of increased circulation of dust and lint. Sources of ultraviolet radiation should be so situated asto protect the eyes of the occupants of the room from direct or reflected rays. A combination of ultraviolet radiation and dust control 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 practical measures for reducing the total number of respiratory infections among personnel, since exposure by contact is an important factor. Bourdillon and his group concluded that there is justi- - fication for attempting to reduce the load of air-borne microorganisms by the methods now at our disposal.4 They have explored the properties of a number of compounds, and their conclusions are in agreement with those of American investigators. The present status is admirably reviewed by the Committee on Sani tary Engineering of the National Research Council,27 and by a subcom mittee of the American Public Health Association* Both committees feel that the problem of air disinfection is still in the experimental stage. Knowledge concerning the effectiveness of glycol vapors has not kept pace with the development of vaporizing devices, and there is real danger that commercial exploitation of the various devices may discredit the method and discourage careful research in this important field.28 More experi mentation is needed for arriving at a definite conclusion concerning its use in industry and public buildings. VALUE OF AIR COOLING UNDER TROPICAL CONDITIONS The commissioning of a class of naval hospital ships with all wards, laboratories and living spaces air cooled is a notable achievement to pro vide better treatment of patients, especially those suffering from extensive burns, by control of environmental factors. 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 humidity are major factors in prolonging disability and increasing 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 continuously subjected to high temperatures. Even at rest about 50 cc of fluid per hour are lost as sweat29 : through intact skin. In burn patients the difficulty, encountered in tem- ; perate climates, of maintaining fluid and'electrolyte balance is tremendously ; augmented by the additional evaporative fluid loss in hot environments, j Patients who have such varied conditions as heart disease, thyrotoxico- ! sis, shock from any cause, severe hemorrhage, or those who have had an ' anesthetic, will invariably store heat when subjected to a hot, humid envi-j ronment. The gradient between the body surface temperature and the? environmental temperature is such that loss by radiation is slight. Thei heat loss by evaporation in a warm, humid environment is low whetheri the patient does or does not perspire. The heat regulatory center may be! temporarily deranged following an anesthetic, brain injury, or after an; overdose of barbiturate. Loss of fluids and electrolytes is another influ-1 encing factor. Cooling the body is the answer to this problem, 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 controlling tern-J perature height of patients with various acute febrile diseases.80 Air Conditioning in Prevention and Treatment of Disease 137 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 experiments29 it was possible to produce a fulminating type of rash in all men living con tinuously 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 cool 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, intermittent cooling to a degree which prevented sweating in men at rest eliminated a serious handicap to good performance of duty. In both laboratory tests and aboard hospital ships a relatively cool living environment of 76 to 78 ET provided an atmosphere conducive to rest and sleep without excessive sweating. Berthing spaces tended to have ex tremely low odor levels. Motivation, initiative and alertness, in contrast to the usual irritability and lack of incentive incident to residence in tropical climate, were maintained.31 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. It is not improbable that cooled houses in a tropical climate, if used consistently for one generation, would modify the whole character of a population. The obvious advan tages of part time cooling on personnel to promote rest and sleep in tropical areas would provide a prophylactic 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 infante, maternity and delivery rooms, children's wards, clinics for arthritic patients, heat therapy, cold therapy, oxygen therapy, X-ray rooms, the control of allergic disorders, and for the physiological effects in industry. Normal individuals may be subjected to considerable strain in adjusting to hot, humid conditions. Heat loss by radiation is reduced, as is loss by evaporation of sweat. Individuals 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 in creased cell metabolism, and in turn to still greater heat production. This vicious cycle may threaten life if the cardio-vascular or transport mecha nism 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 pa tient with thyrotoxicosis. . Cardiac patients may be unable to maintain the circulation necessary to insure normal heat loss. Individuals with head injuries, those subjected to brain operations, and those with barbiturate poisoning may have hy perthermia, especially in a hot environment, due to a disturbance in the neat regulatory center of the brain. Obviously, one of the most important 138 CHAPTER 7 1954 Guide 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 circulation. 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 solution, plasma or blood to expand the circulating blood volume and thereby improve pe ripheral circulation. A cool environment is valuable in aiding heat loss after adequate skin circulation is established. A hot, dry environment (89.6 F and 35 percent relative humidity) has been used over an extended period for the treatment of patients with rheumatoid arthritis, with reported improvement.32 ( * ' 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 reduce the danger of anesthetic gases; summer cooling with some dehumidification tends to eliminate excessive fatigue and to protect the patient and operating personnel; and finally, filtering aids the removal of allergens from the operating room air. ; , i s j Reducing Explosion Hazard Explosion hazards in operating rooms increased with the introduction of anesthetic gases and apparatus. Ether administered by the old drop method gives rise to an explosive 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 explosion hazard may be as great as with ethylene-oxygen, or cyclopropane-oxygen mixtures. Of the anesthetic gases nitrous oxide alone does not explode but supports combustion. Ether, vinyl ether, ethylene, and cyclopropane are as poten tially dangerous as gasoline or illuminating gas in the home.33 Chloroform does not explode 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 dra-\ matic features surrounding an explosion justify continued investigation ; to eliminate the hazard. During the course of ethylene anesthesia, the mixture, usually 80 per- i cent 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 j into the air may accumulate to any lower concentration, and thus introduce j 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. J Even when this procedure is omitted, it is difficult in practice to avoid * dilution of the anesthetic gas with air during the normal course of breathing J following the administration. In either case the mixture would pass 3 through the explosion range and extraordinary precaution is necessary for f the safety of the patient and operating personnel. J In a study34 of 230 anesthetic explosions and fires, 70 percent of the ex-1 Air Conditioning in Prevention and Treatment of Disease 139 plosions and 60 percent of the deaths were caused by igniting agents other than static sparks. The National Fire Protection Association36 made certain recommendations for safe practice based on available informa-' tion in Pamphlet No. 56, Recommended Safe Practice for Hospital Operating Rooms (July 1952). These recommendations outline in some detail 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 observed by hospital personnel. The requirements and recommendations are interdependent and each will be ineffective unless coordinated with the other. To approach complete success in the preven tion of anesthetic explosions, all persons--the surgical staff, the nursing staff, the maintenance staff and administrative personnel--must be edu cated and periodically reminded of the explosive nature of combustible anesthetic agents. Experience has shown that neither high humidity nor intercoupling devices have eliminated the danger from static electric discharge. The removal of gas concentrations from the operating table area, by means of specially devised exhaust ventilation, should be thoroughly tested. Port able duct systems as installed aboard ship should be acceptable. Serious explosions can occur in a closed system, but proper precautions 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 A.S.H.V.E. Research Laboratory, 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 quality also in creases the safety factor of anesthetic administration. Operating Room Conditions Little is known about optimum air conditions for maintaining 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 regulate body temperature. From this it was concluded that all anes thetized patients suffered considerable heat loss, although there may be little more than 0.8-F variation in the rectal temperature during the course of the operation.33 The severe physiological effects, such as excessive sweating and rapid pulse, of high operating room temperatures on attend ants and patients during the hot months signify the need for proper cool ing. 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.36 Although the comfortable air conditions for the operators are not identi cal with those for the patient, it is usually not difficult to compromise within a range of 55 to 60 percent relative humidity and 72 to 80 F temperature. The work just cited reported that 68 to 70 F effective temperature not only 140 CHAPTER 7 1954 Guide furnished comfort for the operating room workers, but apparently pre vented exhaustion of the patient as evidenced by rapid convalescence in the recovery ward. Additional heat may be furnished to the patient locally or by suitable covering, according to body-temperature in individual 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 attempts to remove or kill pathogenic organisms. The bacterial content of conditioned operating rooms is generally lower than that of non-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 hours37 without replenishment. The removal of bacteria by the process of air cooling and condensation of mois ture out of air, merits further study.38 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 flowing through a system of mechanical cleaners which protect the patient against infection from attendants, and from bacteria-containing air in the corridor or ward.39 Operations are frequently postponed on allergic patients during asthmatic manifestations through fear of complications. . The removal of airborne allergens, therefore, is in some cases an important function of the air con ditioning system in preparing patients for operation. Central system air conditioning plants and unit air conditioners pro ducing between 8 and 12. air changes per hour of adequately filtered and properly conditioned air are generally acceptable to the medical profession for operating rooms. Opinions vary considerably on the use of all outside air versus recirculation for operating rooms. There is a current trend among eminent authorities on anesthesiology to recommend that a mini mum of 50 percent outside air be introduced to the operating room, with a maximum of 50 percent recirculated filtered room air. A separate ex haust fan system is usually necessary to confine and remove the gases and odors. Double windows are desirable and often necessary to prevent con densation and frosting on the glass in cold weather, and to minimize drafts. The air flow of 8 to 12 air changes in operating rooms should: (1) reduce the concentration of the anesthetic to well below the pharmacologic threshold in the vicinity of the operating personnel; (2) remove the great amounts of heat and sometimes moisture, from sterilizing equipment if inside the operating room, from the powerful surgical lights, from solar heat, and from the bodies of the operatives; and (3) provide extra capacity for quickly preparing the room for emergency opera tions. Much can be gained by thermal insulation of sterilizing equipment, and by thorough exhaust ventilation of sterilizing rooms adjoining the operating rooms. An air conditioned recovery ward in connection with the air conditioned operating room, is of great value in stabilizing 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 system is not fully developed, with the resultant tendency for environmental temperature to influence body temperature. Air Conditioning in Prevention and Treatment of Disease 141 The younger the premature infant, the greater is the tendency. 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 in fection 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 in-, valid if environmental conditions are not identical, since fluid and electro lyte 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 research30 at the Children's Hospital, Boston, Mass., using four valid criteria, namely, stability of body tempera ture, gain in -weight, incidence of digestive syndromes, and mortality. Individual 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 move ment less than 20 fpm. A single nurseiy conditioned to 77 F and 65 percent relative humidity was found to fulfill satisfactorily the requirements of the majority of pre mature infants. Additional heat for weak (or debilitated) infants may be furnished in the cribs or by means of electric incubators placed inside the conditioned nursery, and the temperature adjusted according to individual requirements. In this way 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. i-iiniuruxiux oj numiauy: mtnougn external neat is an important factor in the maintenance of normal body temperature, humidity appears to be of equal or greater importance. When the premature nurseries at the Children's Hospital were kept at relative humidity between 25 and 50 percent for two weeks or longer, the body temperature became unstable, gain in weight diminished, the incidence of gastro-intestinal disturbances increased, and the mortality rose. On the other hand, continuous ex posure to air conditions with 55 to 65 percent relative humidity gave satisfactory results over a period of years. The initial physiologic loss of body weight (loss occurring within first four days of fife) was found to vary inversely with the humidity. In the old nurseries with natural humid ity it averaged 12.4 percent of the birth weight; in the conditioned nur series 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 conditioned 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, per sistent vomiting, diminishing gain or loss of body weight, and other symp toms, were generally from two to three times as high under low as under high humidity. - Summarizing, the best chances for life in premature infants are created by maintaining a relative humidity of 65 percent in the nursery, and by 142 CHAPTER 7 1954 Guide providing a uniform environmental 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 importance. 5 Air Conditioning Equipment. t 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 dehumidification in hot weather. A ventilation rate between 8 and 12 air changes per hour is desirable to remove odors and main tain uniformity of temperatures in extremes of weather. Recirculation should not be used in these wards owing to odors and the possibility of infection. There should be a frequent change in spray water. . 7 t ' 7 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 con- ' ditioning alone did not prevent the spread of respiratory cross-infections.41 ? Bacterial ultraviolet barriers, air conditioning and mechanical barriers are efficient. 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 considered an imitation . of nature's way of overcoming invading pathogenic organisms. The action J; 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 re- ' sistant organisms, by general mobilization of the defensive mechanisms of ; the body. Although the action may be direct and specific by destruction of the invading organisms within the safe human limits, fever therapy exerts ~ much of its benefit through the improvement of the mechanism of bodily defense. A serious challenge to the theory on which fever therapy is based 'i comes from the demonstration that high fever causes a reduction in the ; concentration of circulating antibodies in experimental animals. Patients for fever therapy should be carefully selected. The most serious complications which may arise are heat stroke, heat exhaustion and cir- culatory collapse. The chief minor complications are heat cramps, fever ij! 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 g 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 g in women, and involvement of the eye), syphilis and chorea. iy The most striking results are seen in gonorrhea and syphilis, since the f, causative organisms can be destroyed at temperatures compatible with fl human life. However, the use of fever therapy has decreased since peni- i cillin has been found so effective in the treatment of gonorrhea and syphilis.'^*? Mild fever, up to 101 F for one hour, has recently been used in the treatment of rheumatoid arthritis. This degree of fever is not bactericidal, but is fj believed to stimulate the body defense mechanism. ` f. Air Conditioning in Prevention and Treatment of Disease 143 Equipment for Production of Fever Artificial fever can be induced by injections of various crystalloid or colloid substances, bacterial products of typhoid and malarial organisms, or by physical methods using hot baths, radiant heat cabinets, hot humidi fied air cabinets, or by short wave diathermy in combination with a cabinet. The relative advantages of various methods have been evaluated clin ically.4^ 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, Qhio. In the earlier studies of the Society, temperatures were elevated more easily using saturated atmospheres. A fever therapy apparatus43 using these same principles has proved efficient as a means of inducing and main taining 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, infrared, 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 procedure, 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 conse quent reflex dilatation of the vessels of the extremities, eliminates this dan ger of local heat application. Short wave diathermy within the cabinet during the induction phase has been used. When the desired body temperature has been reached by elec trical induction, the atmosphere of the enclosure is kept at saturation to prevent heat loss, thus maintaining the patient's temperature at the de sired point. The two underlying principles in the production 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.44 Freezing of the tissue must be avoided. For certain patients, in whom am putation of an extremity is indicated, 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 prepared 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 amputation f an extremity is not indicated, the application of a tourniquet and pack- CHAPTER 7 ing in ice are dangerous procedures, since loss of the limb usually results. An extremity with inadequate blood supply can be readily cooled with out the use of a tourniquet, but such an extremity is also usually even tually lost. Theoretically, 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 extremities with inadequate blood supply remain viable or recover. Packing in ice, or use of low temperatures, is contra-indicated in the treat ment of patients with frostbite, immersion foot or trench foot. The affected ! extremities should be exposed to the air in a 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 available facilities, are as follows:41 . (1) Cracked or shaved ice which is simple and has the advantage of not freezing tissues. However, it is cumbersome and sloppy to handle and is unsuited to pro longed 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. (5) A double chambered cabinet using dry ice has been constructed. (6) Electrical refrigerating apparatus, consisting of a compact noiseless unit that pumps fluid to various types of applications, is available. The applicators may be m 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 inducing dental anesthesia. (7) An air chamber at regulated temperature for treatments of frostbite and im mersion foot, and amputation stumps. The electrical apparatus is costly, but has the advantages of thermostatic regulation, light weight, freedom of movement, and permits prolonged treatments with heat, as well as cold over the range of temperatures thera peutically desirable. ALLERGIC DISORDERS Hay fever, asthma, eczema and contact dermatitis are classified as allergic disorders. The allergic individual responds to contact with a variety of substances, which are innocuous to a non-allergic person, with severe manifestations 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, histamine or a histamine-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 Air Conditioning in Prevention and Treatment of Disease 145 response, a contraction of the smooth muscles of the bronchi resulting in 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 anergic 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 sensi tive to various non-specific stimuli that the threshold of their response to such irritation is considerably lower than that of a non-allergic individual. Air Conditioning Apparatus Of all the measures to relieve a specifically sensitive individual, elimina tion 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 conditioning 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 treatment of asthma, should remove all possible 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 relative humidity well below 50 percent proved satisfactory.4 Di rect 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 conditioning pro cesses, in the control of allergic conditions, are fairly comparable to those ob tained by desensitization treatment, so long as the patients remain in the pollen-free atmosphere. 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. More over, the usefulness 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 ad vantages in the simplicity of treatment, convenience, and under certain conditions, almost immediate relief.48 Pollen cases are usually relieved of most of their symptoms within 1 to 3 hr after exposure to properly filtered *ur. A pollen-free atmosphere is especially valuable when desensitization has given little or no relief, and when desensitization is not advisable owing to mtercurrent 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 in clude pneumonia, severe anemia, cardiac decompensation, pulmonary ate- 146 CHAPTER 7 1954 Guide V Iectasis, 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.47 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. i 1 v 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 tem peratures and humidities are inevitable, increasing 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 hour gives satisfactory results in . patients with fever in a medium size oxygen tent. V Oxygen tents are confining to the patient. They may terrify the restless and delirious patient. Medical and nursing 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 com- fortable. 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, ft 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 ft the gravity type, or of the fan type using mechanical refrigeration or air j; drying agents. .| The temperature and humidity requirement in oxygen therapy depends gprimarily upon the physical condition of the patient, and secondarily upon A* the type of disease. In pneumonias4 prescribed conditions should be a temperature of 60 to 75 F, humidity 50 to 55 percent, moderate air move- ft ment, oxygen concentration of 50 percent, and carbon dioxide of less than p one percent. J Oxygen in Aviation -I | An important application of the principle of oxygen therapy is in aviation. \ At the present time all high altitude military airplanes in this country are |f provided with gaseous oxygen equipment, and military personnel are re- 0 quired to utilize oxygen at all times while in flight above 15,000 ft, or be- E tween 12,000 to 15,000 ft for longer than two hours, or between 10,000 Air Conditioning in Prevention and Treatment of Disease 147 to 12,000 ft for longer than six hours. The use of oxygen in commercial aviation will depend on the height and duration of the flights, as well as the state of health of the passengers. The necessity for portable, comfortable equipment, the possible fire hazards due to smoking, and the use of oxygen on sleeper planes are some of the difficulties facing civil airline operators. The pressure cabin airplane is a solution to the problem. 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 duringthe 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 humidification in winter; it will also help in keeping 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 important. In new hospitals particularly, the desirability of cooling certain sections of the building should be given serious consideration. Financial reasons may preclude the cooling 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 the South, it can be used to ad vantage 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 (70 ET) under all summer outside conditions for general wards and treatment rooms, and 70 F with 30 to 50 percent relative humidity (65-66 ET) for winter conditions. In the operating rooms, 70 F with 50 percent relative humidity (66 EH) 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 exposed 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 resuits.49 Aside from comfort and recuperative. power of the patients, 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 accompany summer heat waves. Problem of Odors The evacuation of battle casualties in aircraft and their subsequent hospitalization have stimulated efforts to minimize odors arising from drain ing wounds, old odorous casts, and gangrenous wounds, For aircraft, chemical sprays arid 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 can be recirculated. 148 CHAPTER 7 1954 Guide Based upon the effectiveness of activated carbon commercially and in- dustrially to adsorb odors, individual adsorption units have been used successfully. In hospital wards the question of superiority of adsorption methods for elimination of odors over other methods remains to be answered. The present status of the problem is that the commercial aspect is highly controversial.60 f 1 i; f * ' REFERENCES 1 The Effects of Atomic Weapons, Revised September, 1950. (For sale by the Supt. of Documents, V. S. Government Printing Office, Washington 25, D. C.). * Investigation of the Smog Incident in Donora, Pa., and Vicinity, by James G. Townsend, M.D. (American Journal of Public Health 40:183-189, Feb., 1950). * The Physiologic Aspects of Atmospheric Pollution, by Carey P. McCord, M.D., (Industrial Medicine and Surgery, 19:97-101, March, 1950). 4 Studies in Air Hygiene, by R. B. Bourdillon, O. M. Lidwell and J. E. Lovelock with W. C. Cawston, L. Colebrook, F. P. Ellis, M. Vanden Ende, R, E. Glover, A. M. Macfarlan, A. A. Miles, W. F. Raymond, E. Schuster and J. C. Thomas (Medical Research Council of Great Britain, 1948. Special Report Series No. 262). ` Ultraviolet Irradiation with Artificial Illumination, by Hans E. Ronge, Uppsala, Sweden, 1948, 191 pages. L'Hygiene du Batiment per L'Ultra-violet by P. A. Burrucand, Centre Scien tific et Technique du Batiment, Paris, 1949. 7 Acceptance of Ultraviolet Lamps for Disinfecting Purposes, Council of Physical Therapy (Journal of American Medical Association, 122:503-504, 1943). * Evaluation of Methods to Control Airborne Infection, by J. E. Perkins {Ameri can Journal of Public Health, 35:891-897, 1945). 7The Present Status of the Control of Airborne Infections, by Committee on Evaluation of Methods to Control Airborne Infections of the American Public Health Association {Journal American Public Health Association, 37:13-22, 1947). " Progress in the Control of Airborne Infections, by Sub-Committee on Air Sani tation {American Public Health Association Yearbook, 40:5, May 1950 p. 82.) 11 Factors in the Control of the Spread of Acute Respiratory Infections with Ref erence to Streptococcal Illness and Acute Rheumatic Fever, by S. M. Wheeler and T. D. Jones {American Journal of the Medical Sciences, 209:58, 1945). / 11 Dust Control, Report on Suppressive Measures for the Control of Dust, to the Standard Methods Committee for the Examination of Germicides and Antibacterial Agents, by Clayton G. Loosli (American Journal of Public Health, Vol. 38, p. 409, March, 1948). 17 Laboratory and Field Studies of Glycols and Floor-Oiling in the Control of Air Borne Bacteria, by A. P. Krueger, et al (U. S. Naval Medical Bulletin, 42:1288,1944). 14 The Lethal Effect of Relative Humidity on Air-Borne Bacteria, by Edward WDunklin and Theodore T. Puck {Journal of Experimental Medicine, 87:87-101, Feb. 1948). 15 Quotation by William Lester, Jr., in Health on the Job, No. 22, February 1949, published by Institute of Industrial Medicine, New York University, New York, N. Y. 16 Bacterial Content of Air in Army Barracks, by H. M. Lemon, H. Wise and M. Hamburger {War Medicine, 6:92, 1944). 17 A Study of the Nature and Control of Air-Borne Infection in Army Camps, by O. H. Robertson, M. Hamburger, C. G. Loosli, T. T. Puck and H. M. Lemon {Jour nal of the American Medical Association, 126:993, 1944). ** Lethal Effects of Triethylene Glycol Vapor on Air-Borne Bacteria and Influ- : enza Virus, by O. H. Robertson, et al {Science 97:142, 1943). j "The Present Status of Glycol Vapors in Air Sterilization, by M. Hamburger, Jr., O. H. Robertson, and T. T. Puck {American Journal of the Medical Sciences,4 209:162,1945). rl 10 Summary of a 3-Year Study of the Clinical Applications of the Disinfection of v Air by Glycol Vapors, by T. N. Harris and J. Stokes, Jr. {American Journal of the" Medical Sciences, 209:152, 1945). ' Air Conditioning in Prevention-and Treatment of Disease . 149 11 Factors of Importance in the Use of Triethylene Glycol Vapor for Aerial Dis infection, by William Lester, Jr., Saul Kaye, O. H. Robertson and Edward Dunklin (American Journal of Public Health 40:813-820, July 1, 1950). 77 Triethylene Glycol Vapor Distribution for Air Sterilization, by Edward Bigg, B. H. Jennings, and F. C. W. Olson (A.S.H.V.E. Transactions, Vol. 53,1947, p. 393). * Glycol Vapors for Disinfecting Purposes, Editorial (Journal of the American Medical Association, 133:696, March 8, 1947). 74 An Experiment with Triethylene Glycol Vapor for the Control of Colds Among Office Employees, by W. J. McConnell (Industrial Medicine, 18:5,192-196, May, 1949). 75 Ultra-Violet Light Control of Air-Borne Infections in a Naval Training Center, by S. M. Wheeler, H. S. Ingraham, A. Hollaender, N. D. Lill, J. Gershon-Cohen, and E. W: Brown (American Journal of Public Health, Vol. 35, p. 457, 1945). 74 An Evaluation of Ultraviolet Radiation of Sleeping Quarters as Supplement of Accepted Methods of Disease Control, by H. G. DuBuy, J. E. Dunn, F. S. Brackett, W. C. Dreessen, P. A. Nealand, and I. Possner (American Journal of Hygiene, 48: 207-226, Sept., 1948), . 77 Recent Studies on Disinfection of Air in Military Establishments (American Journal of Public Health, Vol. 37, p. 189, Feb. 1947). 77 Commercial Exploitation of Glycol Vaporizers (Editorial in American Journal of Public Health, Vol. 39, No. 2, February 1949, p. 222). 77 A Comparative Study of the Effect on Men of Continuous Versus Intermittent Exposure to a Tropical Environment, by N. Pace, M. B. Fisher, J. E. Birren, G. C. Pitts, W. A. White, Jr., W. V. Consolazio, and L. J. Pecora (Research Project X-205, Report No. 2, Naval Medical Research Institute, Bethesda, Md., May, 1945). 70Mechanism of Heat Retention, by F. K. Hick and M. M. Montgomery. (Un published) . 71 Environmental and Physiologic Studies Aboard an Air-Cooled Hospital Ship En Route from Norfolk, Virginia to Canal Zone (U. S. S. Tranquility (AH-14), 6-13, June 1945), by A. R. Behnke (Research Project X-205, Report No. 4, Naval Medical Research Institute, Bethesda, Md., September, 1945). 77 Investigation Into the Effect of Hot, Dry Microclimate on Peripheral Circula tion in Arthritic Patients, by Gunner Edstrom, G. Lundin and T. Wramer (Annals of Rheumatic Diseases, 7:76-82, June, 1948). 77 Fundamentals of Anesthesia (American Medical Association Press, Chicago, III., 2nd Edition, 1944, p. 204). 74 The Hazard of Fire and Explosion in Anesthesia, by B. A. Green (Anesthesiology, 2:144, 1941). 77 Control of Physical Hazards of Anesthesia, by R. M. Tovell and A. W. Friend (Canadian Medical Association Journal, 46:560, 1942). 74 A.S.H.V.E. Research Report No. 1111--Air Conditioning Requirements of an Operating Room and Recovery Ward, by F. C. Houghten and W. I,eigh Cook, Jr. (A.S.H.V.E. Transactions, Vol. 45, 1939, p. 161). 77 Unpublished Naval Studies, by A. R. Behnke and O. Schneider (1940). "Disinfection of Air by Air Conditioning Processes, by C. P. Vaglou and Ursula Wilson (American Association for the Advancement of Science, Publication No. 17, p. 77 The Control of Cross-Contamination by the Use of Mechanical Barriers, by J- A. Reyniers (Aerobiology, American Association for the Advancement of Science, Symposium, 17:254, 1942). . 40 The Premature Infant: A Study of the Effect of Atmospheric Conditions on Growth and on Development, by K. D. Blackfan, C. P. Yaglou and K. McKenzie (American Jowned Diseases of Children, 46:1175,1933). 41 Observations on the Control of Respiratory Contagion in the Cradle, by I. Rosenstern (Aerobiology, American Association for the Advancement of Science, Sym posium, 17:242, 1942). 41 Physical Medicine, by F. H. Krusen (W. B. Saunders Co., Philadelphia and London, 1941). V *J A.S.H.V.E. Research Report No. 1054--Fever Therapy Induced by Condi tioned Air, by F. C. Houghten, M. B. Ferderber, and Carl Gutberlet (A.S.H.V.E. transactions, Vol. 43, 1937, p. 131). A.S.H.V.E. Research Report No. 1161-- CHAPTER 7 1954 Guide 11 5D0U Fever Therapy Locally Induced by Conditioned Air, by M. B. Ferderber, F; C. Hougbten and Carl Gutberlet (A.S.H.V.E. Transactions,.Vo), 46, 1940, p. 307). 44 Refrigeration for Anesthesia and Therapy, by L. W. Crossman and S. K. Salford % (Th"e TMhoedeEmffeHctosopfitLaol,w64R:8e6l,a1ti9v4e5)H. umidity. and Constant Temperature on Pollen Asthma, by B. Z. Rappaport, T. Nelson, and W. H. Welker (Journal of Allergy, 6:11*1H,1o9s3p5)it.al Air Conditioning, by C. P. Yaglou (The Environmen.t and Its Effect ' Upon Man, Harvard School of Public Health, p. 244, 1939). 41 Principles and Practices of Inhalational Therapy, by A. L. Barach (J. B. Lippin4c8 oTtht eCMo.a, nPahgielamdeenlpt hoifaP, nLeounmdoonn,iaM, obnytrJe. aGl,. 1M94. 4B).ullowa (Oxford University Press, p. 4246W0, h1a9t3A7)r.e the Righ.t Conditions for Comf. ort Cooling,, by Cyril Tasker (Heal ingM, POidpoinrsg,PahnydsiAoloirgCy oanndditiCononintgro,l,Abuyg.C, 1. 9P48. ,Mpc. C84o)r.d and Wm. R. Witheridge (Mc Graw-Hill BookCo., New York, 1949). _ CHAPTER 8 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 Gases and Vapors; Combustible Dusts; Atmospheric Pollen; Airborne Bacteria; Radioactive Air Contaminants THE normal constituents of the earth's atmosphere are oxygen, nitro gen, carbon dioxide, water vapor, argon, small or negligible amounts of other inert gases, hydrogen, variable traces of ozone, and small quantities of microscopic and submicroscopic solid matter, sometimes called permanent atmospheric impurities. From the viewpoint of the air conditioning engi neer, all other airborne substances may be termed contaminants. This term is applied preferably, however, to undesirable or chance impurities, since the occasion may arise for adding to the air controlled amounts of solid or gaseous diluents for the prevention of explosions; germicidal vapors or mists (aerosols) for bacteria control; masking substances for odor control; or a substitute for one of the normal gases, as, for example, when helium is used to replace nitrogen in atmospheres for compressed air workers or divers. Control of the chemical quality of air is one of the functions of complete air conditioning, and some knowledge of the composition, concentration and properties of air contaminants under various circumstances is therefore essential. Air contaminants arise from the normal processes of wear, erosion, wind storm, sea-spray evaporation, thermal disintegration, earthquake, volcanic eruption, combusion, manufacturing, transportation, agriculture, and the biochemical or biological processes, of life. They are classified at various times as organic and inorganic, visible or invisible, microscopic or macro scopic, particulate or gaseous, toxic or harmless, beneficial or destructive. The following classification is based chiefly upon the origin or method of formation of air contaminants. CLASSIFICATION OF AIR CONTAMINANTS Dust, Fumes, and Smokes are solid particulate air contaminants. Dusts are solid particles projected into the air by natural forces, such as wind, volcanic eruption or earthquake, and by mechanical processes, such as crushing. Bonding, milling, drilling, demolition, shovelling, conveying, screening, bagging and sweeping. Some of these forces produce dust from larger masses, while others simply disperse materials that are already pulverized. Generally, particles are not called "usl unless they are smaller than about 100 microns. Dusts may be of mineral type, uch as rock, ore, metal, sand; vegetable, such as grain, flour, wood, cotton, pollen; or onimal, such as wool, hair, silk, feathers, leather. Fumes are solid particles commonly formed by the condensation of vapors from ormauy solid materials such as molten metals. Metallic fumes generally occur as j, e oxides in air because of the highly reactive nature of finely divided matter. rear3 may a*BO formed by sublimation, distillation, calcination, or chemical j . 01i whenever such processes create airborne particles predominately below the micron size. Fumes permitted to age tend to flocculate into clumps or aggregates ^rger size, thereby facilitating removal from air. omokes are the extremely small solid particles produced by incomplete combustion 151 'I fl II' i:\\- 152 CHAPTER 8 1954 Guide of organic substances such as tobacco, wood, coal, oil, tar and other carbonaceous materials. The term smoke is commonly applied to the mixture of solid, liquid and gaseous products of combustion, although the technical literature prefers to distin guish between such components as soot or carbon particles, fly-ash, cinders, tarry matter, unburned gases, and gaseous combustion products. The finest particulate constituents arc much less than 1 micron in size, often in the range of 0.1 to 0.3 mi cron. Mists and Fogs are liquid particulate air contaminants. 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 classifications to airborne droplets formed by condensa tion from the vapor state. This arbitrary distinction between mist and fog is of minor importance, as both terms are used to indicate the particulate state of airborne liquids (occasionally termed aerosols). Fog nozzles are so named because of their ability to produce extra fine droplets as compared to the mist from ordinary spray devices. The 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 becomes saturated with that liquid. Many droplets in fogs or clouds are micro scopic and submicroscopic in size, and may be conceived ae the transition state between the larger mists and the vapors. < Vapors and Gases are non-particulate air contaminants. Vapors are the gaseous phase of substances that are either liquid or solid in their commonly known state, examples being gasoline, kerosene, benzene, carbon tetra chloride, mercury, iodine, camphor. Vapors may be changed to the solid or liquid : form by increasing the pressure, decreasing the temperature or applying both proc- -* esses simultaneously. They are removed from the air by condensation with less . difficulty than are the gases. ? Gases are normally formless fluids which tend to occupy a space or enclosure com pletely and uniformly at ordinary temperatures and pressures. The following sub stances qualify as gases: oxygen, nitrogen, carbon dioxide, carbon monoxide, hydro gen, ammonia, sulfur dioxide. Gases, likewise, may be solidified or liquefied by the - proper control of temperature and pressure. :y The preceding classification is not suitable for the airborne living or ganisms, which range in size from the submicroscopic viruses to the largest pollen grains, not considering the smallest insect life. Bacteria range from ij about 0.2 to 5 microns in size, fungus spores from 1 to 10 microns, and pol: ; len from 5 to 150 microns. . SIZES OF AIRBORNE PARTICLES Fig. 1 is a graphic tabulation of the properties of airborne solids and j liquids arranged according to size on the micron scale. There are 25,4001 microns in 1 inch. Particles larger than 10 microns are unlikely to remain suspended inf' air currents of moderate strength, but settle out by gravity at speeds^,' dependent upon the shape, size and specific gravity of the particle, windt velocity, orientation of the collecting surface, and topography. These! larger particles are of major interest to the engineer in the solution of nug sance problems, but it is usually the smaller particles, or those below 1% microns, that remain in the air long enough to be of hygienic as well s|| economic significance. Mg Industrial dust particles are predominantly of the order of 1 micron iijij size. Tremendous numbers are also present in the submicroscopic rangep below 0.5 micron, but those below 0.1 micron are not believed at present) Air Contaminants 153 r______ ___ .Uiu,c, jjuaaiuiy uue to tneir exceedingly small mass in comparison 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). SCALE OF ATMOSPHERIC IMPURITIES I|swPHFE.PR.Mu. fcAITM0ulIt0RP.Ln0CUc6.S(RCoO6IOInTMERNIjEAHTISNSIAQNsCIUmNSHPAIENEORSRGifti t_Mwo ut SETTLING IN RELATION TO PARTICLE SIZE [(LINES Of DEMARCATION' APPRO*.) I J I--SSI ___________ _t ----------------------------------------- ------- -------------------------------- -------------------------1 Compiled by W. Q. Frank and Copyrighted, used by permission. F .ig 1. Sizes and Characteristics of Airborne Particulate Matter The survey1 of atmospheric.pollution in 14 American cities conducted from 1931 to 1933 indicated the average size of outdoor dust particles to be.0.5 micron, as collected by the Owens jet dust counter and measured wader the microscope. Inability of the light field microscope to reveal IS 154 CHAPTER 8 1954 Guide particles in the 0.1 micron vicinity may have influenced the determination of average particle size. The lower limit of particle size visible to the naked eye cannot be stated definitely. It depends not only upon the individual eye, but also upon the shape and color of the particle, intensity and quality of the light, and na ture of the background or opportunity for contrast. Under ideal condi tions 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 visibility probably ranges from 10 to 50 microns. Dusts, powders and granular materials are frequently classified by refer ence to the size of screens used for separation. Particles above 40 microns are said to be the screen sizes and those below, the sub-screen or microscopic sizes. Approximate or theoretical sizes of particles corresponding to the mesh scale of the U. S. Standard Sieve Series are given in Table 1. Microscopic examination of screened dust indicates that the average diameter of a sample of irregular particles may be substantially larger I if f If I S' Table 1. Relation of Screen Mesh to Particle Size U. S. Standard Sieve Mesh... 400 325 200 140 100 60 35 18 Nominal Sieve Opening in 37 44 74 105 149 250 500 1000 -- than the openings of the screen through which it has passed, if the particle shapes deviate considerably from the spherical form.2 The smallest di mension of many such particles will correspond with the maximum per missible distance between the wires of commercial screens made to A STM Standard Specifications. Screening does not give sharp separation into size groups, and accordingly, such a classification is statistical rather than absolute. AIR POLLUTION BY SMOKE, ASH AND CINDERS Total airborne solids settling in urban areas are usually reported as soot fall in tons per (square mile) (month). Such data published for the cities in this country range from 20 to 200 tons per (square mile) (month). To the air conditioning engineer this information may indicate the effective ness of smoke abatement or fuel combusion 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.3,3 Gravimet ric 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 concen trations 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 (lightfield microscope technic) according to the size distribution of Air Contaminants 155 the airborne dust sample. Information of this type for a specified applica tion is best obtained by simultaneous sampling for both counting and weighing and noting carefully at the time all factors that might affect the reproducibility 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 engineer, 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, and segregation of industrial districts are gradually providing effective aid in the solution of this problem. 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 Chap ters 14, 15 and 16 for further discussion on fuel burning technic.) Table 2. Dust Concentration Ranges Location Grains per 1000 Cu Ft* Rural and suburban districts Metropolitan district................. Industrial districts............. Ordinary factories or workrooms Excessively dusty factories or mines. . . Minimum explosive concentrations ' 0.02-0.2 0.04-0.4 0.1 -2.0 0.2 -4 0 4-400 4000-200,000 1 grain per 1000 cu ft = 2.3 milligrams per cubic meter, i os per cubic foot = 1 gram per liter = 1000 grams per cubic meter ' ` Milligrams per Cubic Meter 0.5 -10 10-1000 10,000-500,000 i.iaiiy present ordinances limit tne number of minutes in any one hour that smoke of a specified density (determined by comparison with;a Ringel- mann Chart which is described in Chapter 51) may be discharged. There is now considerable interest and activity in the control of air pol lution factors in addition to smoke. Difficulty in the establishment of acceptable criteria for certain corrosive and irritant gases, such as fluorides and the oxides of sulphur and nitrogen discharged with the gases of com bustion, and the frequently complicated technical and economic problems encountered in, control, have delayed the drafting and enforcement of legislative measures. Recent reports of an increased incidence of diseases, such as pneumonia and lung cancer, in areas high in certain air contami nants, require further critical investigation before acceptance. The values finally adopted will undoubtedly be lower than the M.A.C. (Maximum Allowable Concentration) limits for use in industry, because the exposure is continuous compared with the 8-hour day, 5 or 6-day week upon which M.A.C. values are based, and because the exposed population contains individuals with greater variation in age and health status. In foggy weather,.or with an inversion of atmospheric conditions, accu mulation of gaseous contaminants may cause irritation of eyes, nose, and respiratory passages, and possibly cause even more serious physiological effects. 'The Meuse Valley fog disaster (Belgium 1930) and the Donora smog (Pennsylvania 1948) are classic examples in the history of gaseous air pollution. In both instances it is believed that irritant gases, princi- pally from industrial plants, accumulating during periods of exceptionally prolonged meteorological inversion and fog, contributed to the illness of many persons, and to the death of some who were especially susceptible. Absorption of Solar Radiation Absorption of solar ultraviolet light by smoke and soot is recognized as a health problem in many industrial cities. Measurements of solar radia tion in Baltimore6 by actinic methods demonstrated that ultraviolet light intensity in the country was 50 percent greater than in the city. In New York City7 a loss as great as 50 per cent in visible light was found by photo electric 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 difficulty in the future, but meanwhile many industrial cities must resort to corrective measures by requiring installation of air cleaning devices, alteration of manufacturing processes, or termination of the of fensive operation in residential or commercial districts. . Control of outdoor odor nuisance is especially troublesome because of the extremely minute quantities of contaminant that are capable of offend ing through a wide area. New industrial chemicals with strange or un familiar odors tend to receive more attention from the neighborhood than the customary odors generated by well known processes and raw materials. Methods of odor control currently in use include charcoal, adsorption, scrubbing towers and air washers, chlorination, condensation, masking, passage of the odorous air through combustion chambers, dispersion through a tall stack, and best of all, substitution of less offensive materials whenever possible.8'10'11 . Control of air quality within buildings ventilated for human 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 position in the standards of air quality for indoor comfort. How ever, the engineer will find, at times, that odors originating outside build ings in industrial or business districts may determine the kind and capacity of equipment he must provide for a high quality air supply installation. INDUSTRIAL AIR CONTAMINANTS i| Many industrial processes are sources of contaminants. Their control ? is an important function of the ventilating or air conditioning engineer, it because the atmosphere within buildings is the medium whereby suchi# finely divided matter is dispersed and transported from the source toy? remote locations where it may cause property damage, nuisance, fire, ex- 5% plosion, disease and even death. ^ ' `S Tables 3, 4 and 5 give maximum allowable concentration values fori-* many industrial air contaminants. Some of these values have been pro*-q| posed by ASA Sectional Committee Z37 on Allowable Concentrations of-t| Toxic Dusts and Gases, and others by the Committee on Threshold Limits ^ of the American Conference of Governmental Industrial Hygienists. Ttie'-'f Air Contaminants 157 values have been adopted by the American Conference of Governmental In dustrial Hygienists and by many of the official industrial hygiene agencies. It must be emphasized that these limits in the great majority of in stances are only suggested maximum working levels since they are estimates, based in many cases upon incomplete environmental and medical studies. Where there is agreement between the ASA Standard Z37 and A.C.G.I.H. values, reliability of the ASA Standard is increased. The values are not fixed, but are subject to revision, upward or downward, with the develop ment 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 M.A.C. is usually accepted as the average exposure value when the upper limits do not greatly exceed the'M.A.C. 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 M.A.C. values may be quite different as to phys iological 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 concentration 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 incor porate a reasonable margin of safety in his estimates of ventilation capacity. In Table 3, Column 1 lists the ASA Sectional Committee Z37 M.A.C. values; Column 2, those of the A.C.G.I.H. Committee on Threshold Limits. Column 3 gives the value in grams per cubic meter or ounces per 1000 cu ft for the corresponding A.C.G.I.H. limits; Column 4 shows the liquid ounces of chemical, if liquid at 20 C (68 F), which, if equally dis persed in 1000 cu ft, would give the corresponding M.A.C. In Table 4, Columns 1 and 2 are respectively the M.A.C. values from the ASA and A.C.G.I.H. Committees. In Table 5, the M.A.C. values for industrial dusts as given were obtained from data of the A.C.G.I.H. Committee on Threshold Limits. A.C.G.I.H. limits for either gamma or Roentgen radiations are 0.3 roent gens 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 minimizing the hazard of fire or explosion due to gases and vapors. The need for good ventila tion is not removed by the use of other precautions, such as the elimina tion of known ignition sources, segregation of hazardous operations, adop tion of safe building construction, and installation of automatic alarms, oome safety engineers regard over-ventilation of an operation employing flammable liquids as a legitimate operating charge for the privilege or necessity of using a dangerous process. However, it is not possible to 158 CHAPTER 8 1954' Guide Table 3. Maximum Allowable Concentration op Gases and Vapors ASA Stand ards M.A.C. ppm by volume Acetaldehyde.................................................... Acetic acids................ ...................................... Acetic anhydride.............................................. Acetone.................. '............................................. Acrolein................................................................ Acrylonitrile . ............................ ..................... Ammonia......................................................... . I Amyl acetate.................. .................................. [ Amyl alcohol (iso)............................................ Aniline.................................................................. Benzene (benzol).............................................. Bromine............................................................ 1,3-Butadiene..................................... '......... n-Butanol............................................................ 2-Butanone......................................................... n-Butyl acetate............................... '................ Butyl "celiosolve" (2 butatyethanol)... Carbon dioxide.............................. Carbon disulfide........................... Carbon monoxide......................... Carbon tetrachloride........ '.____ "CeUceoive" (2-ethoxyethanol) "Celloaolve" acetate................... Chlorine............................................................... Chlorobenzene................................................... 2-Chlorobutadiene....................................;... Chloroform.......................................................... 1-Chloro-l-mtropropane................................ Cresol........ I ........ ........................................ Cyclohexane....................................................... Cyclohexanol...................................................... Cyclohexanone.................................................. Cyclohexene................................................. ' Cyclopropane (propane)........................ -- 1-2 Dibrorooethane (ethylene dibromide). o-Dichlorobenrene........................................... Dicblorodifluoromethane.............................. 1.1-Dichloroethane...................... v I....... 1.2-Dichloroethane (ethylene dichloride) 1.2-Dichloroetbylene...................................... Dichloroethyl ether........................................ Di chloromethane.............................................. Dicbloromonofluormethane. ....................... 1.1-Dichloro-l-Nitroethane............. -.......... 1.2-Dichloropropane (propylene dichlo ride) ..................... ^....... ................................... Dichlorotetrafluoroethane............................ Diethyl amine................................................... DimethylaniJine............................................... Dimethylsulfate.............................................. Dioxane................................................................ Ethyl acetate..................................................... Ethyl alcohol..................................................... Ethyl amine..................................................... Ethyl benzene................................................... Ethyl bromide.................................................. Ethyl chloride................................................... Ethylene chlorhydrin.................................... J Ethylene oxide.................................................. Ethyl ether......................................................... Ethyl formate........................ .......................... Ethyl silicate...................................................... Fluorine................................................................ Fluorotrichloromethane................................. Formaldehyde................................................... Gasoline......................... ..................................... Heptane............................................................... 20 100 Threshold Limit Values A.C.G.1-H* 1953 Gm/cu m or Oz/lOOO cu ftb Oa/lOOO cu ft 20100 5 1000 20 100 200 100 5 0.05 35 1000 100 250 200 200 502000 100 25 200 100 1 75 25 12000 ' 5 400 100 100 400 400 25 50 1000 100 100 200 15 500 1000 10 75 1000 25 51 100 400 1000 25 200 200 1000 5 100 400 100 100 u. i 1000 5 500 500 0.36 0.02554 0.02085 2.4130 0.1145 0.04336 0.069 1.064 0.36 0.019 0.11393 0.00653 2.210 0.3030 0.735 0.948 0.966 0.0622 00-.175376 0.54 0.3465 0.0905. 0.488 0.101 0.022 1.375 0.409 0.401 1.34 0.6875 0.3005 4.94 0.405 0.4051 0.794 0.0878 1.74 4.20 0.0589 0.3265 6.98 0.045 0.02475 0.00515 0.36 1.44 1.881 0.868 0.892 2.64 0.01645 0.18 1.212 0.303 0.851 5.62 0.006135 2.045 2.05 0.43 0.02 0.02 2.42 0.013 0.05 1.16 0.41 0.02 0.12 0.03 3.3 0.36 0.88 1.04 1.02 0.05 0.095. 0.76 0.53 0.3 0.09 0.31 0.08 0.02 1.69 0.42 0.41 1.58 0.91 0.24 3.18 0.33 0.31 0.59 0.08 1.25 2.83 0.4 0.29 4.36 0.07 0.02 0.003 0.33 1.52 0.96 0.59 2.75 0.015 0.09 1.87 0.315 0.87 3.7 2.89 2.87 Air Contaminants 159 Table 3. Maximum Allowable Concentration op Gases and Vapors ...(Concluded) . Substance ASA Stand- M.A.C. ppm by volume Threshold Limit Values A.C.GJ.H. 1953 . ppm Gm/cu m or Os/1000 cu itl> Oz/1000 cu ft Hexane............. . . . Hydrogen chloride. Hydrogen cyanide . Hydrogen fluoride.. Hydrogen selenide.. Hydrogen sulfide... Iodine................ Isophorone........ Isopropyl alcohol Isopropyl ether.. Mesityl oxide__ Methyl acetate.. Methyl alcohol.................... ............................ Methylal...... ......................................... ............. Methyl bromide....................... ................ Methyl butanone............ ................................. Methyl "celloaolve" (2-methoxyethanol).. Methyl "cellosolve" acetate............. .. -- . Methyl chloride.................... 771 ."fr............... Methyl chloroform (1-1-1. trichlorocthane) , Methyicyclohexane.................................. Methylcydohexanol.................... ................... Methylcyclobexanone..................................... Methyl formate................................................ Methyl iso-butyl ketone........ - Monochlorobenzenec.............. Monoftuorotrichloromethane. Naphtha (coal tar)................ Naphtha (petroleum)........ .. Nickel carbonyl..................... Nitrobenzene................................... ............... Nitroethane.................................. .................. Nitrogen oxides (other.than nitrous ox ide) ............................................................ Nitroglycerine.................................................. Nitromethane................................................. 2-Nitropropane................................................ Nitrotoluene.......... Octane................' "......................... Ozone................* ' ]........................... Pentane................. ............................ Pheno^006 (methyt propanone), 200 . i00 Phosgene.................... Phosphine.... ...... Phosphorus trichloride i7>?LPyl acetate___ t>bine................... . Stoddard solvent.....! Styrene monomer. fur chloride. Sulfur dioxide.......... ' 2;'rctr!lchloro<ithan<i ToluTna0rOCthylene....... ......... AMncrPhleonrotieneth.y..le..n.e. YXmyylelnceh..l.o.r.i.d.e. 400 200 200 200 500 5 . 10 3 0.05 20 1 . 25 400 500 50 200 200 1000 20 100 25 25 100 . 500 500 - 100 100 100 100 75 1000 200 500 1 1 100 25 0.5 100 50 5 500 1 1000 200 5 1.76 0.00746 0.01104 . 0.00245 2.54 0.004 . 0.015 0.003' 0.01039 0.141 . 1.022 2.085 0.2005 0.606 . 0.2618 3.11 0.0778 0.352 0.7775 0.1208 0.2086 2.005 0.466 0.458 0.2554 . 0.409 0.3465 5.61 0.638 1.945 0.00697 0.00503 0.307 0.00464 0.2495 0.182 0.028 2.33 2.94 0.704 0.0002 0.15 1.22 2.75 0.22 0.62 0.32 3.5 0.04 0.41 0.078 0.11 0.22 2.44 0.49 0.48 0.25 0.49 0.3 3.59 0.71 2.6 0.006 0.004 0.275 -' 0.003 0.21 0.17 0.23 3.17 4.5 0.82 0.05 0.5 200 0.1 500 200 1 10 5 200 200 5 200 100 500 200 0.00281 0.834 2.845 0.85 0.00552 0.343 1.358 0.752 0.0219 1.072 0.556 1.28 0.868 0.0018 0.885 3.4 0.89 0.003 0.02 0.810 0.83 0.02 0.70 0.58 1.33 0.96 bA.C.GJ.H. American Conference of Governmental Industrial Hygienists. Liquid.ounces (at 20 C) o! chemical in 1000 cu It. From 1951 list. apply a reasonable safety factor to the ventilation estimate without con sideration of the concentrations of gases or vapors that approach the danger point. Safety engineers prefer tu limit the concentration to or | of the lower explosive limit, and this fact should be given full weight in determin ing 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 ex M plosive range is too great. Ability of a flammable liquid to form explosive mixtures is determined largely by its vapor pressure, volatility, or rate of evaporation. Flash Table 4. Limits fob Toxic Dusts, Fumes and Mists Substance A.S.A. Standards, M-A.C. . mg/cu m Threshold Limit Values, A.C.QJ.ff1953 mg/cu m Antimony............................................................................................. Arsenic.................................................................................................... Barium................................ ................................................................... Cadmium.............................................................................................. Chlorodiphenyl.................................................................................... Chromic acid & chromates as CrO*.......................................... . Cyanide as CN................ ..................... ............................................ Dinitrotoluede........ .......................... ............................................... . O-Dinitrocresol.................................................................................... Fluorides................................................................................ .............. Iron Oxide fume................................................................................ Lead................. ..................................................................................... Magnesium oxide fume.................................................................. Manganese............................................................................................ Mercury................................................................................................. Parathion {O.O-diethyi-O-p-nitrophenyl thiophasphate). Pentachloroanphthalene................................................................ Pentachiorophenol.......................................................... ................. Phosphorus (yellow).. ;................................................................. Phosphorus pentachloride...................................... ................ Phosphorus pentasulfide.................................. ........................... . Selenium as Se.................................................................................. Sulfuric add...................................................................................... Tellurium........................................................................,................ Tetryl.................................................................................................... Trichloronaphthalene......................................... ........................... Trinitrotoluene................................................................................ Uranium (soluble compounds)................................................ Uranium (insoluble compounds)............................................. Zinc oxide fumes............................................................................ 0.1 (W) point is a convenient method of expressing this property in terms of the U temperature scale. It may be defined as the temperature to which a com- v bustible 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 r vapors must be applied with caution; the reader is referred to other publi-J? cations for this information.12'13 . Design of equipment for the control of combustible anesthetics is out-S' lined in Chapter 7. Construction of equipment for handling air contain-.? Air Contaminants 161 ing flammable substances, or operating in atmospheres so contaminated, is discussed in Chapter 46. ' It is customary to report the concentrations of flammable gases or vapors in percent by volume, or volume percent. Comparison with concentra tions 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 all of the substances listed have lower explosive limits above 1.0 percent, 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 explosion often originates Table 5. Limits fob Minebal Dusts - Substance Threshold Limit Values A.C.G.l.H. 1952 mppcf* . Alunduro......................................... .Asbestos.......................................... Carborundum.................... Dust (nuisance, no free silica)'. Mica (below 5% free silica) -- ___ J cement........................ .. Silica--high (above 50% free SiOj). Silica--medium (5 to 50% free SiOt) Silica--low (below 5% free SiOi) .... Slate (below 5% free SiOi)................. Soapstone (below 5% free SiOi)......... Total dust (below 5% free SiOi) appcf million particles per cubic foot of sir. standard light Held count. 50 5 50 5200 50 250 50 60 20 50 Irom a small amount of dust in suspension exposed to a source of ignition and the pressure and vibration it creates may be sufficient to dislodge large accumulations of dust on horizontal ledges or surfaces of the building and equipment, thereby creating a secondary explosion of great force. Thus the air conditioning engineer is involved for two reasons: (I) to obtain a movement of dust-laden air into exhaust hoods or openings, and through ventilating or pneumatic conveying ducts, in a manner that will prevent accumulation of highly flammable dust at points where it could ignite inside the equipment; and (2) to so design process ventilation as to prevent the escape of dust which might settle on horizontal surfaces and become a potential source of disaster at some distance from the dusty operation. (See Chapter 46). Intensity of a dust explosion depends upon: chemical and thermal Properties of the dust; particle size and shape; concentration in air; propor tion 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 oust cloud. Investigations on the explosibility of dusts require determina- n of the maximum pressure developed during explosion of a known air concentration, as well as determination of the rate of pressure rise. In- 162 CHAPTER 8 1954 Guide Fl.AMMABII.iTY OF SINGLE CASKS AND VAPORS Table 6. Approximate Limits of Temperatures . and Pressures____________ _______ In Air at Ordinary Gas ob Vapob Lower Limit . Pebcent by Volume Uppeb Limit Pebcent by Volume Closed Cupb Flash Point* Fahbenheit NBFU 1 CLASSIFI CATION Acetyldehyde. Acetone....... Acetylene........ Allyl alcohol.. Ammonia........ Amyl alcohol............... Amyl chloride . .......... Amylene .......... ......... Benzene (benzol) - Benzyl chloride.......... Butane................................. Butyl acetate.................... Butyl alcohol.................... Butylene........................... Carbon disulfide............ Carbon monoxide.......... Crotonaldehyde............ . Cyclohexane.................... Cyclopropane.................. Decane.............................. Dichloroethylene (1, 2) Diethyl selemde............ Dioxane'............................ Ethane .............. Ether (diethyl)............ Ethyl acetate............................ Ethyl alcohol............................ Ethyl bromide.......................... Ethyl cellosolve....................... Ethyl chloride.......................... Ethylene-..-.-- .................. Ethylene dichlonde................ Ethyl formate.......................... Ethyl nitrite.............................. Ethylene oxide.......................... Furfural (125 C) . .................... Gasoline (variable)................ Heptane..................................... Hexane.............. . .................... Hydrogen cyanide................ Hydrogen sulfide. Illuminating gas (coal gas). Isobutyl alcohol....................... Isopentane........................... .............. Isopropyl acetate Isopropyl alcohol Methane.................... Methyl acetate.. Methyl alcohol... Methyl bromide.............. Methyl butyl ketone... Methyl chloride ............ Methyl cyclohexane... Methyl ethyl ether........ Methyl ethyl ketone .. Methyl formate........' Methyl propyl ketone. Natural gas (variable) . Naphtha (benzene)----- Naphthalene...................... Nonane............................ Octane.............................. paraldehyde...................... Pentane........................... 4.0 2.5 2.5 2.5 15.5 1.2 1.6 1.6 1.3 1.1 1.4 12..70 1.2 122..15 1.3 2.4 0.67 > 9.7 2.5 2.0 3.1 1.8 2.2 3.3 62..76 4.0 26..72 2.7 3.0 3.0 2.1 1.41-.10.5 1.2 5.6 4.0 4.3 5.3 1.7 1.8 2.0 5.0 3.1. 6.7 13.5 1.2 8.2 1.1 2.0 1.8 5.0 1.5 4.3 1.1 0.9 0.83 0.95 1.3 1.4 57 12.8 .80 -26.6 6.8 .8.4 15.0 9^7 50 74.2 15.5 8.4 10.5 2.6 12.8 22.2 12.5 36.5 11.5 19.0 11.3 15.7 14.8 28.6 15.9 16.5 50 80 7.4-7.6 6.0 6.9 40.0 74.2 45.5 33.0 . -17 `70 . 100 "12 140 "84 -22 "55 1 *U5 57 "54 -49 28 54 104 -58 "56 -31 140 -50 25 -15 "82 . 7.8 15.6 15.5 36.5 14.5 8.0 , 18.7 . io.i 9.5 22.7 8.2 13.5 6.0 2.9 3.2 ^8 . 43 53 "U 52 "25 -35 30 -2 2CMi0 176 88 56 1 * 2 3 1 3 3 1 2 1 3 2 2 1 2 3 1 2 1 3 2 1 3 2 2 1 2 2 2 1 3 3 2 Air Contaminants 163 Table 6. Approximate Limits of Flammability of Single Gases and Vapors In Air at Ordinary Temperatures and Pressures* (Concluded) Gas ob Vapob Loweb Limit Pebcent .by Volume Uppeb Limit Percent by. Volume Closed Cupb Flash Point Fahrenheit NBFU CLASSI7ICATION Propane................................................ Propyl acetate................................ Propyl alcohol................................ Propylene................... ........................ Propylene dichloride................. Propylene oxide.............................. Pyridine.................. ..:........................ Toluene (toluol)............................ Turpentine......................................... Vinyl ether........................................ Vinyl chloride................................. Water gas (variable).................. Xylene (xylol)................................. 2.1 1.8 2.1 2.0 3.4 2.0 1.8 1.3 0.8 1:7 4.0 6.0 1.0 , 10.1 8.0 13.5 11.1 14.5 22.0 12.4 . 7.0 27.6 21.7 70 6.0 58 59 60 ' . 74 .40 . 95. ,, 2 2 2' 3 2. 3 63 2 * Adapted from: Fire and Explosion Hazards of Combustible Gases and Vapors, by G. W. Jones; Chapter 13, Industrial Hygiene and Toxicology, edited by F. A. Patty (Interscience Publishers, 1948); Properties of Flammable Liquids, Gases and Solids (Associated) Factory Mutual Fire Ins. Cos., January (1940); and National Fire Codes for Flammable Liquids, Gases, Chemicals and Explosives--1945 (National Fire Protec tion Association). -. b Closed cup refers to the equipment used in flash point determinations. - c From Standards for Storage, Handling and Use of Flammable Liquids (National Board of Fire Un derwriters, Pamphlet No.-2,.April 1952). . vestigators 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 already tested range from 0.01 ,to 0.5 oz per cubic foot, or 10 to 500 grams per cubic meter of air. Maximum pressures generated have been reported as high as 500 psi, although they are more likely to be of the order of 50 psi. Investiga tions on the flammable characteristics of dusts are currently made at 0.1 and 0.5 oz. per cubic foot.15-21 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 Disorders in Chapter 7, and Air Cleaning, Chap ter 34). Whole grains and fragments transported by the air range chiefly between 10 and 50 microns in size, but some have been measured as small as 5 microns, and others over 100 microns in diameter. Ragweed pollen grams 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 individual pollen grains are available in the botanical literature.22- 2324 Geographical distribution of plants known to produce hay fever is also recorded.25-26 - The quantity of pollen grains in the air is generally estimated by exposing an adhesive-coated glass plate outdoors for 24 hr, and then counting cali brated areas under the microscope. Methods.are available for determinlng the number of grains in a measured volume of air,25 -27- 28 but their greater accuracy has not caused them , to replace the more simple gravity slide method used for most pollen counts. . Counting technics vary some what, but the daily pollen counts reported in local newspapers during the. rtf ir ' I .i Ii CHAPTER 8 hay fever season usually represent the number of grains found on 1.8 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 maximum 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 grains 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 1 sq cm of a 24-hr gravity slide, depending on grain diameter, shape, specific gravity, wind velocity, humidity and physical placement of the collecting plate.29'3031 AIRBORNE BACTERIA Study of the occurrence and significance of micro-organisms in the at mospheres 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 conclusive index of the potential health hazard of a given environment. The reported number of airborne organisms may vary from 1 to 1000 per cubic foot of air, influ enced somewhat by the method of testing.32 Many are attached to the dust particles present in the air. . Where it seems advisable or desirable to control the bacterial content of rooms, public conveyances or buildings, highly effective methods are available (see Chapter 7), and their extended use may do much to assist the workers in this field in accumulating the necessary mass of evidence that will decide the practical value of air sterilization for the control of communicable disease. It is now well established that ultraviolet radia tion is feasible for the protection or preservation of pharmaceuticals, cos metics, and food products. m RADIOACTIVE AIR CONTAMINANTS33 Radioactive air contaminants are physically similar to ordinary indus trial and chemical plant contaminants. They differ from ordinary con taminants, 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. Concentrations resulting from absorptions by plants and subsequent feeding of animals in the magnitude of several thousand times, is not unusual. Tolerances for radioactive con-; taminants have been established and are under continuing study and re view. Guidance in regard to tolerance levels for discharge of contaminated air in different types of localities can best be had from the classified litera ture which is available through proper clearance procedures. REFERENCES 1 Atmospheric Pollution of American Cities for the Years 1931 to 1933, J. E. Ives, et al (U. S. Public Health Service Bulletin No. 224, March 1936). s Micrometries, The Technology of Fine Particles, by J. M. DallaValle (Pitman Publishing Corporation. 1943). Air Contaminants 165 * Atmospheric Pollution Due to Smoke, by A. C. Stern (Heating and Ventilating, May, 1945). Atmospheric Pollution Due to Dust and Cinders, by A. C. Stern (Heating and - Ventilating, July, 1945). * Sootfall Studies_for New York City, by J. Siegel and B. Feiner (A.S.H.Y.E. Journal Section, Heating, Piping and Air Conditioning, September, 1945, p. 495)' 5 The Use of Fuel Consumption and Equipment Data in the Abatement of Atmos pheric Pollution, by A. C. Stern (A.S.H.V.E. Journal Section, Heating, Piping and Air Conditioning, August, 1945, p. 447-454). * Effects of Atmospheric Pollution Upon Incidence of Solar Ultra-Violet Light, by J. H. Shrader, M. H. Coblentz and F. A. Korff (American Journal of Public Health, Vol. 19, 1929, p. 7). 7 Studies in Illumination--III: A Study of the Loss of Light Due to Smoke on Manhattan Island, by J. E. Ives (17. S. Public Health Service Bulletin No. 197, June, 1930). * Study and Control of Industrial Atmospheric Pollution Nuisances, by F. M. Stead (American Journal of Public Health, Vol. 35, May, 1945, p. 491-498). * Evaluation of Odor Nuisance in the Manufacture of Kraft Paper, by J. M. DallaValle and H. C. Dudley (U. S. Public Health Service Reprint No. 2022, Public Health Reports, Vol. 54, January 13, 1939, p. 35-43). " Disposal of Refinery Wastes, Section II: Waste Gases, Vapors, Sludges and Dusts (American Petroleum Institute, New York City, 1938). 11 Offensive Trades, by David Ronald (William Hodge and Co., London, 1935). 17 Limits of inflammability of Gases and Vapors, by H. F. Coward and G. W. Jones (V. S. Bureau of Mines Bulletin No. 279, 1939). 13 Inflammation Limits and Their Practical Application in Hazardous Industrial Operations, by G. W. Jones (Chemical Reviews, Vol. 22, February, 1938). '* Private Communication, by Hylton R. Brown (Bureau of Mines, College Park, Maryland). 15 Explosibility of Agricultural and other Dusts as Indicated by Maximum Pres sure ana Rates of Pressure Rise, by P. W. Edwards and L. R. Leinbach (U. S. De partment of Agriculture Technical Bulletin No. 490, October, 1935). 7*Dust Explosion Hazards in Plants Producing or Handling Aluminum, Magne sium, or Zinc Powder, by H. R. Brown (U. S. Bureau of Mines Information Circular No. 7148, March, 1941). . 17 Inflammability and Explosibility of Metal Powders, by I. Hartman, J. Nagy, and H. R. Brown (U. S. Bureau of Mines Report of Investigation No. 3722, October, 1943). . ^ 13 Inflammability and Explosibility of Powders Used in the Plastics Industry by I. Hartman and J. Nagy (V. S. Bureau of Mines Report of Investigation No.N3751, May, 1944). . ' 17 Industrial Dust Explosions, by H. R. Brown (V. S. Bureau of Mines, Infer tion Circular No. 7309, January, 1945). 70 Proposed Code for the Prevention of Dust Explosions in the Plastics Industry (National Fire Protection Association, Boston, May, 1945). 71 National Fire Codes for the Prevention of Dust Explosions (National Fire Pro tection Association, Boston, 1944). Contains codes for aluminum, magnesium, coal, pulverized fuel, flour, spice, starch, sugar, cocoa, sulfur and wood. 52 An Introduction to Pollen Analysis, by G. Erdtman (Chronica Botanica Co.> Waltham, Mass., 1943). 71 Pollen Grains, by R. P. Wodehouse (McGraw-Hill Book Co., New York, 1935). 71 Atmospheric Pollen, by R. P. Wodehouse (Aerobiology, p. 8-31, Publication No. 17, American Association for the Advancement of Science, Washington, D. C., 1942). ig^Hay/ever Plants, by R. P. Wodehouse (Chronica Botanica Co., Waltham, Mass., ,, 77 Hay Fever: A Geographical and Botanical Survey, by E. R. Squibb and Sons, Aew York, 1937. ' 77 Techniques for Appraising Air-Borne Populations of Microorganisms, Pollen and Insects (Phytopathology, Vol. 31, March, .1941, p. 201-225). _ " Apparatus for Determining the Pollen Concentration of the Atmosphere, by B. J. Lody, W. F. Kinney and N. A. Kerstein (Research Department, the Detroit Edison t'Ompany, Detroit). 166 CHAPTER 8 1954 Guide 33 The VoIumetricTncidence of Atmospheric Allergens, by O. C. Durham (Journal of Allergy, Vol. 14, September, 1943, p, 455-461). . 30 The Volumetric Incidence of Atmospheric Allergens, II: Simultaneous Measure ments by Volumetric and Gravity Slide Methods, by O. C. Durham (Journal of Allergy, Vol. 15, May, 1944, p. 226-235). . 31 Air-Borne Fungus Spores as Allergens, 0. C. Durham (Aerobiology, p. 32-47, Publication No. 17, American Association for. the Advancement of Science, Washington, D. 3C3 .S, a1m94p2li)n. g Devices, by H. G. DuBuy a.nd A. Hollaender (American Journal of Medical Science, Vol' 209, February, 1945, p. 172-177). 33 Ventilation Problems in Safe Handling of Radioactive Materials, by W. W. McIntosh, paper presented at ASMB Spring Meeting, March 1952. BIBLIOGRAPHY Abstracts and Bulletins (monthly, annual and special) Industrial Hygiene Founda tion, Inc., Pittsburgh, Pa. ._ . Aerobiology, Publication No. 17 (American Association for the Advancement of Science, Washington, D. C., 1942). ' Air Sanitation and Industrial Ventilation, by W. N. Witheridge (Detroit, Mich., 1945). : . .. . . American Industrial Hygiene Association Quarterly (4400 Fifth Ave., Pittsburgh, Pa.). . : . ... . ' Analytical Chemistry of Industrial Poisons, Hazards and Solvents, by M. B. Jacobs (Interscience Publishers, New York, 1941), Bibliography of Industrial Hygiene, 1900-1943 (U. S. Public Health Service Bul letiCnloNuod.s 2a8n9d, 1S9m4o5k)e, s, by. W.E,Gibbs (P. Bl. a`kiston's Son & Co., Philadelp, hia, Pa., 1. 92D4)e.termination and Control of Industrial Dust, by Bloomfield and DallaValle (U. S. Public Health Service Bulletin No. 217, 1935). , . Dust, by S. C. Blacktin (The Sherwood Press, Cleveland, 1934). (The) Environment and Its Effect upon Man (Harvard School of Public Health, BosIntodnu, s1t9ri3a7l).Dust, .by Drinker and Hatch (McGraw-Hill Book Co., New York, 1936). Industrial Health Engineering by A. D. Brandt (John Wiley & Sons, Inc., New YoIrnk,du19s4tr7i)a.l Hygiene and Toxicol.ogy. , edited by F. A. Patty (Interscience Publishers, Inc., New York, Vol. I, 1948 and Vol. II, 1949). Journal of Industrial Hygiene and Toxicology (monthly) (Harvard School of Public Health, Boston, Mass.). See cumulative abstract and subject indexes. Manual of Industrial Hygiene, by W. M. Gafafer, et al (V. S. Public Health Service, W. B. Saunders Co., Philadelphia, 1943). Noxious Gases and the Principles of Respiration Influencing Their Action, by Hen derson and Haggard (American Chemical Society Monograph Series No. 35, Reinhold, NewOcYcouprka,tio1n943a)n. d Health, two volumes. (International Labor Office, Washington, D. CTo.)x. icology and Hygiene of Industrial Solven. ts, by Lehmann and Flury, trans lated by Eleanor King and H. F. Smyth, Jr. (Williams and Wilkins, Baltimore, 1943). HEAT TRANSMISSION COEFFICIENTS OF BUILDING MATERIALS Beat Transfer Symbols; Calculating Overall Coefficients; Conductivity of Homo geneous Materials; Soil Conductivity; Surface Conductance; Air Space Con-ductance; Practical Coefficients and Their Use; Computed Coefficients of Walls, Roofs, Ceilings and Floors; Combined Ceiling and Roof Co : , -efficients; Calculating Surface Temperatures THE design of air conditioning or heating systems for buildings requires a knowledge of the thermal properties of the walls enclosing the space. (The term watts in this case, includes windows, doors, ceilings, floors, roofs and skylights). The rate of heat flow through the walls under steady-state conditions at design temperatures is usually the basis for calculating the heat required. For a given wall under standard conditions the rate is a specific value designated as U, 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 testing of all combina tions of building materials is impracticable, the procedure and necessary data for calculation of the value of U are given in this chapter, together with tables of computed values for the more common constructions. HEAT TRANSFER SYMBOLS U = overall coefficient of heat transmission or thermal transmittance (air to air); the time rate of heat flow expressed in Btu per (hour) (square foot) (Fahrenheit de gree 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 con ductance on both sides. . :: k = thermal conductivity; the time rate of heat flow through a homogeneous mate rial under steady conditions through unit area per unit temperature gradient in the direction of the gradient. Its value is expressed in Btu per (hour) (square foot) (Fahrenheit degree per inch of thickness). Materials are considered homogeneous when the value of k is not affected by variation in thickness or size of sample within the range normally used in construction. . C = thermal conductance; the time rate of heat flow through a unit area of a mate rial 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 de gree). The term is applied to specific materials as used, either homogeneous or het erogeneous. : / = 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 i 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 temperature difference between the boundary surfaces. Its value is expressed in Btu per (hour) (square foot of area) (Fahrenheit degree). Fhe conductance of an air space is dependent on the temperature difference, the height, the depth, the position and the character of the boundary surfaces. The relationships are not linear, and accurate values must be obtained by test and not by computation. . = thermal resistance. Its value is obtained from the reciprocal of heat trans fer as expressed by U, k, C, / or o. It is expressed in (hours) (square feet) (Fahren- ' 167 168 CHAPTER 9 heit degrees) per (Btu). For example, a wall with a U value of 0.25 would have a resistance value of 1/0.25 * 4.0. Therefore, 4 hr would be required for the flow of one Btu for each square foot of area and each degree of temperature differential. . CALCULATING OVERALL COEFFICIENTS From Chapter 5, Equation 7, the total resistance to heat flow through a wall is equal numerically to the sum of the resistances in series. . R? = .R\ + Rt -KRi + Ri d- ... + Ra (1) where, R,, Rt, etc., are the individual resistances of the wall components. Rt = total resistance. For a wall of a Bingle homogeneous material of conductivity h and thickness x, with surface coefficients /, and * Heat Transmission Coefficients, of. Budding. Materials 169 requires considerable-skill and experience to obtain accurate results. It is recommended that thermal conductivities of homogeneous materials be determined by means of the Guarded Hot Plate.1 For determination of conductances, a Guarded Hot Box method1 is generally, used. Tables- I .and 2 give conductivities and conductances which are quite generally used in calculation, and which have been selected from various sources. Wherever possible, the properties of the material and test con ditions are given. In selecting and applying heat transmission values to any construction, caution is necessary, since coefficients for the same mate rial may differ because of variations which occur in test methods, in the materials themselves, or in the temperature of the material when tested. Conductivity of Homogeneous Materials Thermal conductivity is a property of a homogeneous material and of types of building materials such as lumber, brick, and stone, which may be considered homogeneous. Most insulating materials, except reflective t: 1, orFig. Typical Variation iUflAfflAU Wvuuaa>... ______ Density--fob Fibrous Material Then by definition, V ~ l/Rr For a wall with air space construction and consisting of two homogeneous materials of conductivities fci and fa, thicknesses zi and **, respectively, and separated by an air space of conductance a, j*T-i+S + I + 5+i f\ k, a fa /,, (3) .m and U = 1/Rr In the case of types of building materials having non-uniform or irregu lar 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 fa The resistance of the section 1fC is therefore substituted for x/k in Equations 2 and 3. CONDUCTIVITIES AND CONDUCTANCES The method of calculating the overall coefficient of heat transmission for a given construction is comparatively simple, but accurate values of con ductivities and conductances must be used to obtain satisfactory results. In addition, there are sometimes parallel heat flow paths of different re sistances in the same wall, and these may necessitate modification of the formula. In such cases calculated results should be checked by test. w Tho determination of the fundamental conductivities and conductances Fig. 2. Typical Variation op Thermal Conductivity with Mean Temperature types, are of a porous nature and consist of combinations of solid matter with small air cells. The thermal conductivity of these materials will vary with density, mean temperature, size of fibers or particles, degree and extent of bond between particles, moisture present, and the arrange ment 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. I. It will be noted that for each there is an optimum density for lowest conductivity: Typical varia tion of conductivity with mean temperature is shown id Fig. 2. Thermal Conductivity of Soil . The following statements are based largely on results of. a study* made in the Engineering Experiment Station, , University of Minnesota. :and pub lished in BiiUetin No. 28. Tests were made on nineteen different soils which represented a wide textural variety, including gravel, sand, sandy loam, silt loam and clay, as well as some crushed rocks and a fibrous peat. Moisture contents in tests varied from air-dried values to those greater than the optimum moisture content; densities 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 aegree of influence of temperature depends upon whether it is above or below frees- Position of Surface Direction of Heat Flow Surface Emissivity . e * 0.83 e - 0,05 a u I Vertical................................................................. Upward Downward Horizontal 1.95 1.21 1.52* ' 1.16 0.44 0.74 ' Section B. Conductance of Vertical Spaces at Various Mean Temperatures1 Mean Temp Fahr Deg 20 40 60 80 100 120 140 Conductances of Air Spaces for Various Widths in Inches . 0.128 2.300 2.470 2.650 2.819 2.990 3.167 3.340 0.250 1.370 1.480 1.590 1.702 1.813 1.928 2.035 . 0.364 1.180 1.288 1.390 1.492 1.600 1.700 1.800 0.493 1.100 1.193 1.295 1.390 . 1.486 1.580 1.680 0.713 1.040 1.125 1.210 1.295 1.380 1.467 1.550 1.00 1.030 1.112 1.195 1.280 1.362 1.445 1.530 1.500 1.022 1.105 1.188 1.270 1.350 1.435 1.519 Section C. Conductances and Resistances of Air Spaces Faced on One Surface with Reflective Insulations - Location and Position of Air Space Direction op Heat Flow Temp4* Diff Fans Deo Winter Summer Rafter Space (8 in.) Horizontal Horizontal Horizontal Horizontal 30 deg slope 30 deg slope 30 deg slope 30 deg slope Stud Space (3* in.) . Vertical1' Vertical Vertical-^ Vertical Vertical* Down Up 45 45 Down Up Down Up 45 45 Down 1 ' Up Horizontal Horizontal Horizontal Horizontal Horizontal 30 40 30 25 25 25 25 15 20 Conductance (C) Resistance* G) No. of Air Spaces . No. of Air Spaces I 2 Z 123 ________ -- ----------- ----- ------ 0.10 0.27 0.09 0.24 0.15 0.25 0.13 0.23 0.07 0.17 0.06 0.16 0.10 0.17 0.09 0.14 10.00 3.70 11.11 4.17 6.67 4.00 7.69 4.35 14.29 5.8S 16.67 6.25 10.00 5.88 11.11 7.14 0.34 0.32 0.46 0.23 0.18 0.13 0.11 2.94 3.13 2.17 .4.35 5.56 7.69 9.09 . A.S.H.V.E. Transactions, Vol. 44, 1938, p. 513.) . . A.S.H.V.E. Research Report No. 825--Thermal Resistance of Air Spaces, by F. B. Rowley and A. B. Algren (A.S.H.V.E, Transactions, Vol, 35, 1929, p. 165). . e Thermal Test Coefficients of Aluminum Insulation for Buildings, by G. B. Wilkes, F. G. Hechler and E. R. Queer (A.S.H.V.E. Transactions. Vol. 46, 1940). . d Temperature difference is based on total space between plaster base and sheathing, flooring or roofing-. * These air space conductance and resistance values are based on one reflective surface (aluminum) hav ing an emissivity of 0.05 facing each space, and are based on total space between plaster base and sheathing." flooring or roofing. The rafter and stud spaces are divided into equal spaces. f Stud space is lined on plaster base side with loose paper with aluminum on surface facing air space- The resistance of the small air space between the plaster base and paper was 0.43. * p Radiation and Convection Across Air Spaces in Frame Construction, by G. B. Wilkes and C- M. F. Peteraon (A.S.H.V.E. Transactions, Vol. 43. 1937, p. 351). * The recommended surface conductance for calculating heat losses for still air for non-reflective surfaces is 1.65 Btu. For a 15 mph wind velocity, the recommended value is 6.0 Btu. These coefficients wero de rived from Fig. 4, which was based on tests conducted at the University of Minnesota, and apply to vertical surfaces. ' ` 3*1 Heat Transmission Coefficients of BiuIding^Materiais 171 Table 2. Conductivities (k) and Conductances (C) of Building and Insulating Materials . These constants are expressed in Btu per (hour) (square foot) (Fahrenheit degree temperature difference) Londtictivtiies (k) are per \nch thickness and.conductances (O are for thickness or _______ ___ construction stated, not per inch thickness. Material Description Conduct ivity or Conduct ance Per ` For | Inch j Thick- (*) (C) Thickr. ness j ness ; Listed j G) 1(e) BUILDING BOARDS (Non-Insulating)......... Compressed cement and as bestos sheets.......................... Corrugated asbestos board.. Pressed asbestos mill board.. Gypsum board--gypsum between layers of. heavy. . paper......................................, 1 in. gypsum board................ 1 in. gypsum board.............. . i in. gypsum board................ 118 20.4 60.5 FRAME CONSTRUC- TION COMBINA- TIONS. 1 in. fir sheathing and build ing paper.............................. 1 in. fir sheathing, building paper and yellow pine lap siding..................................... , 1 in. fir sheathing, building paper and stucco................. Pine lap siding and building paper, siding 4 in. wide___ Yellow pine lap siding.......... MASONRY MATERIALS Brice............................................. Damp or wet.......................... Common yellow clay brick One tier yellow common clay brick, one tier face brick, approx. 8 in. thick.. 4.1 0.48 0.84 0.24 2.08 1.19 3.73 2.82 2.60 0.85 1.28 5.0* 4.8 0.20 0.21 Clay Tile Hollow.. 2 in; Tile, $ in. plaster both sides................ ......................... 4 in. Tile, J in. plaster both sides....... ................................. 6 in. Tile, J in. plaster both sides.-....................................... 8 in. Tile, average of 8 types (Walls No. 59, 63, 64, 66, 67, 90. 91. 92)....................... 12 in. Clay tile wall: 8 in. x 5 in. x 12 in. and 4 in. x 5 in. x 12 in.......................... 120.0| 127.0 0.60 0.47 -- I -- I 0.26 Authorities: ' ((12)) (3) 0.27 0.35 0.38 (3) (1) (4) 2.00 1.22 1.18 0.78 (4) (4) (4) (4) (2) (4) (4) (2) (2) (2) (4) (4) 1 National Bureau of Standards, tests based on samples submitted by manufacturers. * A. G. Wihard, L. C. Lichty and L. A. Harding, tests conducted at the University of Illinois. * J. C. Peebles, tests conducted at Armour Institute of Technology, based on samples submitted by manu facturers. ' - 4 4 F. B. Rowley, et al, tests conducted at the University of Minnesota. * A.S.H.V.E. Research Laboratory- ' 1 E. A. AUcut, tests conducted at the University of Toronto. .,."See Thermal Conductivity of Building Materials, by F. B. Rowley and A. B. Algren (University of Minnesota Engineering Experiment Station Bulletin No. 12). * Heat Transmission Through Insulation as ASecfced by Orientation of Wall, by F. B. Rowley and C. L. Lund (A.S.H.V.E. Transactions, Vol. 49, 1943, p. 331). . c The Effect of Convection in Ceiling Insulation, by G. B. Wilkes and L. R. Vianey (A.S.H.V33. Trans actions. Vol. 49. 1943, p. 196). .. - , 0 See A.S.H.V.E. Research Report No.- 915--Conductivity of Concrete, by F. C- Hougbien and Carl Gutberlet (A.S.H.V.E. Transactions. Vol. 38. 1932. p. 47). - e See Heating, Ventilating and Air Conditioning, by Harding and Willard, revised edition, 1932. ^ See BMS13, U. S. Department of Commerce, National Bureau of Standards, Washington, D. C. ' 9 Roofing, 0.15 in. thick (1.34 lb per square foot), covered with gravel (0.83 lb per square foot), combined tuicknneessss aassssnumm*eHd n0.25. 172 CHAPTER 9 1954 Guide Table 2: Conductivities (k) and Conductances (C) of Building and Insulating Materials--Continued 1- These constants are expressed in Btu per (hour) (square foot) (Fahrenheit degree temperature difference). Conductivities (A) are per inch thickness and conductarices (O are for thickness or :i,ruction stated, Tiot per inch thickness. Material Description fa a Conduct- P Q 1V1TY OR Resistance u Conduct- a H P* H < fa ance s 2 Per For Inch Thick- Thick- ness 3 t* <*) CO ness Listed 0 CD 2 < aa QS G) Cc) 6 < MASONRY MATERIALS --(Continued)Concrete.. .......................... Sand and gravel aggregate! various ages and mixes... -- 11.35 -- to 16.36 Sand and gravel aggregate.. 142 75 12.6 Limestone aggregate............... 132 75 10.8 Cinder aggregate...................... 97 75 4.9 Steam treated limestone wtftg aggregate**.................v-. 74.6 75 2.27 Pumice (Mined in Cali fornia) aggregate..;..:.-... 65-0 75 2.42 Expanded burned clay ag gregate.................... 59.9 75 2.28 Burned clay aggregate. J -- 67.1 75 2.86 Blast furnace slag aggregate 76.0 70 1.6 Expanded vermiculite ag gregate...................................... 90 Expanded vermiculite ag gregate.......................... 26.7 90 . 0.76 Expanded vermiculite ag gregate.............. ...................... 35 90 0.86 Expanded vermiculite ag gregate...................................... 50' 90 1.10 Expanded Vermiculite ag gregate, 1:9.4 mix.... ... .... 26-3 119 0.97 Expanded Vermiculite ag gregate, 1:2.9 mix............... . 45.6 119 1.60 Perlite aggregate, 1:10.3 mix. 24.4 119 0.75 -Perlite aggregate, 1:2.9 mix. 47.6 II9: 1.45 Concrete plank........................ 76 75 2.5 Cellular concrete.................... * 40. C 76 1.06 Cellular concrete.................... 50.C 75 1.44 Cellular concrete.......... . 60. C 75 1.80 Cellular concrete.................... 70.C 75 2.18 Air-cooled slag aggregate.'.. 124.2 ' 119; 5.3 Air-cooled slag aggregate -.: 124.9 119 .5.9 -- -- -- -- - -' __ -- -- -- - - __ -- -- -- -- -- -- -- -- -- 0.09 to 0.06 0.08 0.09 0.22 0.44 0.41 0.44 0.35 0.63 1.47 1.32 1.16 0.91 1.03 0.63 1.33 0.69 0.40 0.94 0.69 0.56 0.46 0.19 0.17 -- (5) -- -- (4) -- (4) -- (4) - (4) -, -- -- __ (4) m (4) (3) (3) - (3) . - (3) (3) - CD -- Cl) -- -- -- -- 1 S3 (3) -- (3 -- (3) -- (3) -- (1) -- ' (1) 8 In. Concrete Blocks 8 in. three oval core, sand and gravel aggregate.'... 8 in. three oval core, crushed limestone aggregate......... 8 in. three oval core, cinder aggregate.............................. . 8 in. three oval core, burned clay aggregate...................... 8 in. three oval core, ex panded blast furnace slag aggregate.................... 8 in. three oval core, cooled slag aggregate . 126.4 134.3 86.2 67.7 -- -- 40 40 40 40 40 40 _ 0.90 -- 0:86 - 0.58 - 0.50 -- 0.49 - .0.68 -- - -- - 1.11 1.16 1.73 2.00 (4) (4) (4) (4) 2.04 1.47 (4) (4) 12 In. Concrete Blocks I U <* CO0* BM* tffi OF 1 !w 12 in. three oval core, sand and gravel aggregate . 124.9 . 40 . 86.2 12 In. three oval co burned clay aggregate 76. V 40 40 0.78 - 0.53 0.47 - 1.28 1.88 2.13 (4! (4) (4) See footnotes on first page of Table 2. Heat .Transmission Coefficients of BuUding Materials 173, Table 2. CoNDTKITIVITIES (k) AND CONDUCTANCES (C) OF BUILDING AND 1 Insulating Materials--Continued ' '' - Theee amstanU^reex prcased in* tBjhtiu* jpjectr ^(hour) (square foot) (Fahrenheit degree temperature difference.) Conductivities (A) are per inchh thickneosos and cwornnd*uccitaTnvc*.e3*i _,>,- r.r' . ... _______ construction stated, --notip__e__r.-incLh,tLhicLknIe' ss' ' ' / Material Description fa *0 a Conduct p 0 Q as ivity OB Conduct Resistance aa a < ance fa fa G) G)A * * Ba 2 a (W aa H 2 < a Per. For Inch Thick w Thick ness (O ness listed O 1 QS MASONRY MATERIALS --(continued) Gypsum........................................ 3 in. solid gypsum partition tile............................................ 3 in. three cell gypsum par : tition tile 4 in. three cell gypsum par ' ` tition tile. 87J percent gypsum, 12| percent wood chips........... ---- -- '-- 51.2 74 2I41 0.42 0.74' . 0.60 - 1.66 - * 0.60 PLASTERING RIALS MATE Gypsum plaster...........:____ Gypsum plaster, | in. thick Cement plaster....................... Wood, lath and plaster, to tal thickness f in. Gypsum plaster and ex panded .vermiculite, 4 to 1 mix. . ................................. Gypsum vermiculite plaster " Mix. 100 lb:'2 cu ft.............. Mix. 100 lb: 3 cu ft.'.. /: ;.. Gypsum perlite plaster '-Mix. 100 lb: 2 cu ft.............. Mix. 100 lb: 3 cu ft........ ; Gypsum sand plaster ' Mix. 100 lb: 200 lb............. Mix. 100 lb: 3001b............... Insulating plaster 0.9 in.-thick applied to { in. gyp. sum board.....................`......... _ . -- 73 -- -- 70 3'30 -- 8.00 39.9 75 : 0.85 46.7 - 63 1.84 43.5 64-. 1.63 49.1 : 64' 1.68 42.5 64- 1.35 104 53- 5.55 107 52 : 5.77 54.0 75 _ 8.80 -- 2.50 -- __ -- __ -- . -- 1.07 0.30 0.13 - 1.18 0.54 0.61 0.60 0.74 0.18 0.17 -- ROOFING woods Asbestos shingles.................... Asphalt, composition or prepared.................................. Asphalt shingles..................... Built-up roofing, bitumen1 ` or felt, gravel or slag ' surfaced*................................. Slate.............................................. Wood shingles............................ Balsa..................................... Balsa......................... ........... Balsa..................................... %California redwood, 0 moisture................................. Cypress........................................ Douglas fir, 0 % moisture.. Eastern hemlock, 0 % moisture........................... Long leaf yellow pine, 0 % . moisture.................:;.......... Mahogany.................... ;............. Hard maple, 0 % moisture. Maple............................................ Maple, across grain................ Norway pine, 0 % moisture. Red cypress, 0 % moisture. -Red oak, 0 % moisture... Short leaf yellow pine, 0 % moisture....................... ; Soft elm, 0 % moisture... 65.0 75 - 70.0 75 _ 70.0 75- -- -- -- 1.33 -- -- 10.00 ~ ' -- 20.0 8.8 7.3 90- 0.58 90 0.38 90 0.33 28.0 28.7 34.0 75 0.70 86 0.67 75 0.67 30.0 75 40.0 34.3 46.0 44.3 40.0 32.0 32.0 48.0 75 86 75 86 75 75 75 75 0.76 0.86 0.90 1.05 1.10 1.20 0.74 0.79 1.18 36.0 75 0.91 34.0 75 0.88 6.0 6.5 6.5 __ -- 1.28 __ -- -- - -- - _ -- -- -- .-- -- -- -- _ -- - _ -- 0.75 0.10 -- 1.72 2.63 3.03 1.43 1.49 1.49 1.32 1.16: 1.11 0.95 0.91 0.83 1.35 1.27 0.85 1.10 1.14 Sm footnotes on fiist page of Table 2. 1.35 (4) (4) 1.67 (4) -- _ 0.11 (4) (4) (2) 0.40 ' U4) -- ' ' (3) _ (1) -- _ -- Ona>)) (i) -- 0) 0.93 (3) (a)0.17 0.15 (3) 0.15 (3) -- 0.78 (2) __ (1) (1) -- (1) - -- (4) -- (4) 0)__ __ 0) __ __ __ (4$ __ (4) -- (4) __ (4) -- (4) il: - : \l .{!; i- \i !: :: Giju: These constants are expressed in Btu per (hour) (square footj (Fakrenheitdegrees temperature difference.) Conductivities (k) are per inch thickness and conductances (C7) are for thickness or construction stated, not per inch thickness. Material,' WOODS--(continued) Description Soft maple, 0 % moisture.. 42.0 Sugar pine, 0 % moisture.. 28.0 Virginia pine................................ 34.3 West coast hemlock, 0 % moisture................................... 30.0 White pine.................................... 31.2 Yellow pine.............................. . Sawdust,' various....................... 12.0 Shavings, various from planer........................................... 8.8 Shavings, from maple, beech and birch (coarse) -- .... 13.2 "o a Conduct G ivity or Resistance (S X Conduct . ANCE < m & fa Per For B a Inch Thick Thick ness Z ( (C> ness Listed < a (0 G) E % 4K ?r /'m;l it p 75' 0.95 1.05 ; __ . 4 'ftS 75 0.64 -- 1.56 -- (4) 86 0.96 -- 1.04 -- (1) _75 0.79 1.27 -- - S4) 86 0.78 -- 1.28 -- (1) -- 1.00 -- 1.00 -- (3) 90 0.41 -- 2.44 -- (1) 90 0.41 -- 2.44 .-- (1) 90 0.36 - ' 2.78 - (1) INSULATING 1 RIALS.................. Blanket and Insulations-- Chemically treated wood fi bers held between layers of strong paper........ 3.62 Flax fibers between strong paper...................................... - 4.60 Chemically treated hog hair between kraft paper--. .. 5.76' Chemically treated hog hair, between kraft paper and asbestos paper.......... . 7.70 Hair felt between layers of paper............................. . 11.00 Kapok between burlap or . paper................................. . 1.00 Stitched and creped ex panding fibrous blanket . 1-50 Paper and asbestos fiber with emulsified asphalt binder........................................ . Cotton insulating bat............ . f 4.2 0.875 6.25 Cotton fibers _ Short Staple Linters, ) Fireproofed........................ ) 4.50 2.45 1.60 0.85 0.65 Felted cattle hair................ Felted cattle hair................ :13.00 11.00 Felted hair and asbestos. . 7.80 Ground paper between tv layers, each 2 in. thi< 70 , 90 71 71 75 90 70 94 . 72 .90 90 90 90 90 90 90 90 90 6.25 0.28 0.26 0.28 0.25 0.24 0.27 0.28 0.24 0.25 0.24 0.24 0.26 0.29 0.30 0.26 0.26 0.28 _ _ - -- - - - _ -- -- -- -- -- -- -- -- -- 4.00 3.57 3.85 3.57 4.00 4.17 3.70 3.57 4.17 4.00 4.17 4.17 3.85 3.45 3.33 3.84 3.84 3.57 (3) (1) - (3) - (3) - (3) - in - (3) _ (B -- s3 -- a) --a --m -- (D -- (; -- 0) -- (1) -- (1) O') thick). Mineral Wool. . 12.1 | 4.5 Reflective..................... -.... See Table 1. Section C........... j -- Insulating Board............. Made from sugar cane fiber.. 13.5 Made from hard wood fibers. 15.20 Made from wood fiber............ i!5.90 Made from wood fiber............ jlS.OO Made from wood fiber.............1 -- Made from wood fiber............. J5.20 Made from wood fiber.......... 16.90 Made from licorice root ........ 16.1 i in. insulating boards with- i out special finish-' (eleven 1 samples)..................................... 16.5 21.8 1 in. insulating board............13.2 See footnotes on first page of Table 2. 75 0.40 0.27 -- --- 70 0.33 -- 70 -- 72 0.33 -- 70 0.33 -- 52 0.33 -- 0.33 -- 90 0.34 -- 81 0.34 90 0.33 to -- 0.40 -- -- 0.34 _ 3.70 - 3.03 3.U3 3.03 2.94 3.03 to 2.50 2.94 2.50 (4) --i -- -- --. -- -- -- - D e n b itt (L b per C u F t) J A u th o r ity 1 M e a n e m p ( F a h r D e g )T A u th o r ity | Heat. Transmission Coefficients of Building Materials 175 Table 2. Conductivities (k) and Conductances (C) of Building and Insulating Materials--Concluded These constants are expressed in Btu per (hour) (square foot) (Fahrenheit degree temperature differences.) Conductivities (k) are per inch thickness and conductances (C) are for thickness or construction stated, not per inch thickness. Material Description "P fa a O Kfej fa n > f' a Q Conduct ivity or Conduct ance r Resistance Per For Inch Thick Thick ness < (O ness Listed G) G) INSULATING MATERI- Made from ceiba fibers........... ALS--(Continued) Made from ceiba fibers........... Loose Fill Type............... Chemically treated wood fibers...................................... ...... Fibrous material made from . dolomite and silica...: Fibrous material made from . slag................................................ Redwood bark........................... Redwood bark...................... . Glass wool fibers 0.0003 in. --to 0.006 in. in diameter... Granular insulation made from combined silicate of lime and alumina.................. Expanded vermiculite .-... Regranulated oork about in. particles............................. Hand applied granular mineral wool 2 in. to 6 in. thick, horizontal posi- tion . No covering........... 4 in. machine blown granu- lar mineral wool, horizon- tal position. No cover- ing................................................ Rock wool................................... 1.90 75 1.60 75 4.0 75 1.50 75 9.40 103 3.00 90 5.00 1.50 75 4.20 72 7.0 . 70 8.10 90 6.05 -- to 7.13 -- 5.74 -- 10.0 90 0.23 0.24 0.28 0.27 0.27 0.31 0.26 0.27 0.24 0.48 0.31 0.30 to 0.33 0.30 0.27 Slab Insulations............... Corkboard, no added binder. Corkboard, no added binder Corkboard, no added binder. Corkboard, no added binder. Corkboard......... .................... Corkboard. asphaltic binder Chemicallv treated hog hair with film of asphalt............. Sugar cane fiber insulation blocks encased in asphalt membrane..........'.................... Made from shredded wood and cement........................ .... Made from shredded wood and cement........................ Cellular glass................................ Cellular glass................................ 14.0 10.6 7.0 5.4 8.7 14.5 10.0 13.8 24.2 29.8 9.0 9.0 90 0.34 90 0.30 90 0.27 90 0.25 -- 0.29 90. 0.32 75 0.28 70 0.30 72 0.46 -- 0.77 75 1 0.42 50 0.40 See footnotes on first page of Table 2. __ __ 3.57 __ 3.70 __ 3.70 __ 3.22 __ 3.84 __ 3.70 __ 4.17 __ 2.08 __ 3.22 -- 3.33 to -- 3.03 __ __ __ _ __ __ __ 3.33 ~ 3.70 _ 2.94 -- 3.33 __ 3.70 __ 4.00 __ ' 3.45 __ 3.12 __ 3.57 __ -- __ __ __ ___ _ __ 3.33 __. __ 2.17 ,,__ 1.30 . __ __ 2.38 -- 2.50 -- (3) M> (3) (3) (3) 0) n) (4) (4) (1) 0) (1) (1) (1) (4) (]) (3) (3) m (4) (I1n) >ng. For increases of moisture content exceeding about 6 to 12 percent, the conducivity 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 fro"16 manne.r/or a11 soils, at any moisture content, and for either the frozen or unze.a c?nd>t>on. On the average, each one pound per cubic foot increase in dry ensity increases the thermal conductivity by about 3 percent. Fjfecf of Moisture. An increase in moisture content, up to the point of saturation, ses 'V' ,lncrease *n thermal conductivity. The rate of increase in typical soils as as follows: average conductivities, in Btu per (square foot) (hour) (FahrenDer ae,gree.Per inch), of four sands at a density of 110 lb per cu ft were: 6.8 at 2.5 of afi n?oisture> 8-9 at 5 percent moisture, 11.2 at 10 percent moisture. Five soils a, iQDe tKxture at a density of 100 lb per cu ft, gave average conductivities of 6.7 percent moisture, and 9.5 at 20 percent. Thus, the doubling of moisture con- tent within the ranges cited increases the. conductivity by approximately 30 or 40 ||| percent. At higher moisture contents the percentage increase `would be less. ' Jg tmiVincelyrahl icgohmfopor scicti&ornsSo'ftBthXetusr&odilssaolislso affdecrtcsi&thtie'^ccioynidotuvcltuivx'ituyu. s'QicuAavrUtzicutends to agive ?} 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 Sf points are illustrated by the values in Table 3 which lists seventeen soils in approxi mate order of their magnitude of thermal conductivity from greatest to least for f-jf- seven different density-moisture content conditions: Some of the values in this table have been determined by extrapolation and are consequently approximate.,S t Blank spaces in the table indicate that the density or moisture content, or both, me 0 such that no tests were possible for that condition or that no tests were sufficiently \ : .> ' ' . ->|1 Table 3. Thermal Conductivity (k) Values op Soils in Approximate Order . of Decreasing. Values0 \ .' ,, ': Mean Temperature--40 F ' -K Soil No. P4714 P4703 P4701 P4709 P4604 P4601 P4705 P4706 P4711 P4704 P4713 P4502 P4503 P4708 P4602 P4710 P4505 Moi3TDbe Contend--% ' - ,- 4 | 4 | , 4 ,|. 10 | 10 | 20 | 20 Soil Designation ! . Dby Density-lb peb cu it , 100, no ; 120 Fine Crushed Quart* " Crushed Quarts Graded Ottawa Sand ' Fairbanks Sand Lowell Sand Chena River Gravel Crushed Feldspar Crushed Granite Dakota Sandy .Loam Crushed Trap Rock Ramsey Sandy Loam . Northway Fine Sand .. Northway Sand Healy Clay Fairbanks Silt Doam " . ' : , 12.0 * 11.5 10.0 8.5=fc 8.5 16.0: 16.0 14.0 10.5 11.0 22.0 13-5 9.0=1= 13.0 6.0 7:5 9.5 5'5 7.5 . .10:0 6.5 9.5 5.0 6.0 7.0 4.5 6.5 4.5 ! 1 5.5 4.5 ; 6.0 4.0 Fairbanks Silty Clay Loam Northway Silt Loam Btu per (square foot) (hour) (Fahrenheit degree per inch). ' 90 110 15.0 13.5 13=fc 10.0 8.5 7.5=fe 5.5 9.0 5.0 9.0 6.0 9.0=1= 4o 7.0=1= 90 100 n 8.0 10.0 7.5 10.0 7.5 9.5 6.0=1= 7.0=fc close to permit a reasonable extrapolation of the data. .Granular soils, particularly;!"; those with high quartz contents, head the tabulation or have the greatest conduc-^j tivity at a given condition. Sandy loam soils are midway in the table and grained soils such as clay and silt loam are last. `' ' V Estimating Thermal Conductivity. The four diagrams of Fig. 3 are presented toA1 aid in the estimate of the thermal conductivity of any soil. Two of the charts are;) for sands or sandy, soils, and two for silt and day soils. One of the diagrams ,fop, each type of soils is for the frozen, and.the.other for the unfrozen condition, . It expected that these charts will give conductivity values with, a precision of 25 per-si cent.' The effect of. such factors as density, moisture content, freezing, or texture; may be easily'approximated by. use of these graphs.' ; . ` - . ' ' *1?^' Specific Heat of Soils Tests to determine specific heat were run . on twelve soils. On five oh the soils, tests were'made at three or four mean temperatures varyingf from about 10 to 140 F. The specific' hekt values of all'twelve soils varied?, by only a small amount (about 0.01), and averaged 0,19 at 140 F! Tbtej 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^ Heat Transmission Coeffitients of Building Materials 177 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 heat transfer to" or from the wall by radiation, convection and conduction. 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 (emissivity), the temperature difference between them* and the solid angle through which they see each other. The heat transfer by convention and conduction is Fig. 3. Determining Thermal Conductivity of Soils from Density anp ' Moisture Content if. controlled by the roughness of the surface, by air movement, and tempera ture 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 radiation, is illustrated in Table 4, which applies to a vertical surface at 80 F, with ambient air at 70 F and effective emissivity equal to 0-83.4 .! 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 24.) The convection part of the surface conductance is affected markedly V air movement. This is illustrated by Fig. 4, which shows the results of tests6 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 con ductances include the radiation portion of the coefficient which, for the conditions of the tests, was about 0.7 Btu per (hr) (sq ft) (F deg). More recent tests7 on smooth surfaces show that surface length also affects sig- 178 CHAPTER 9 1954 Guide nificantly the convection part of conductance; the average value de creases as the surface length increases. Moreover, observations8 of the magnitude of low temperature radiant energy received from outdoor sur roundings 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 conductance coefficients for a practical building becomes a matter of judgment. In calculating the overall heat transmission coefficients for the walls, etc., of Tables 6, 7, 8, 9,15,16,17,18,19, and 21,1.65 has been selected as an average inside surface conductance, and 6.0 as an average outside surface conductance for a 15 mph wind. Both values combine the effects of convection and radiation, and are applicable to ordinary building materials. They should not be used for low emissivity surfaces such as bright metal. Values of V for windows in Table 20 have been computed from somewhat different data, as described in a later section, in order to give proper weight to actual surface con ductance. . In special cases, where surface conductances become important factors in the overall rates of heat transfer, more selective coefficients may be Table 4. Vabiation in Surface Conductance Coefficient for Vertical Surfaces with Different Temperatures of Surrounding Surface Surrounding Surface Temperature 75 F 70 F 69 F 60 F Convection--Btu per (hr) (sq ft).. Radiation-- Btu per (hr) (sq ft)... 6.6 4.4 11.0 6.6 8.6 15.2 6.6 9.6 16.2 6.6 17.0 23.6 required. Data given in Table 1, Section A, and 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 boundary surfaces as well as the intervening air; consequently, the factors influencing sur face conductance play an important part in determining the conductance of the air space. The coefficients given for air space conductance represent the total conductance from surface to surface. The radiation portion of the coefficient is affected by the difference in temperature between the boundary surfaces and by their respective emissivities, and is practically independent of depth. The convection and conduction transfer is controlled by depth and shape of the air space, the roughness of the boundary surfaces, the mean temperature, and the direc tion of heat flow. For air spaces usually employed in building construction, the radiation and convection factors vary independently of each other. Table 1, Section B gives experimentally-determined conductances of vertical air spaces bounded by such materials as paper, wood, plaster, etc., having emissivity coefficients of 0.8 or higher, and having extended parallel surfaces perpendicular to the direction of heat flow. The conductances decrease as the depth is increased, but change only slightly for spaces greater than f in. Air space tests reported by Wilkes and Peterson, gave conductance values for air spaces of 3f in. depth having boundary surfaces with emissivity values of 0.83 as follows:9 vertical, 1.17; horizontal (heat flow upward), 1.32; horizontal (heat flow downward), 0.94. Since, in buildings, the same constructions may be used for conditions where the direction of heat flow may be in one direction or its opposite, and since much of the construction involves vertical air spaces, an average value of Heat Transmission Coefficients of Building Materials 179 1.10 Btu per (hour) (square foot) (Fahrenheit degree temperature differ-, ence) was chosen for use in calculating the overall coefficients in Tables 7 to 19 wherever air spaces f in. or more in depth were involved. If one or both boundary surfaces of an air space are faced with metals which have low emissivity surfaces, the radiant heat transfer will be greatly reduced in comparison with that occurring from surfaces of ordinary build ing materials. Table 1, Section C gives conductances and resistances of air spaces bounded by one reflective surface with an emissivity of 0.05. These values include heat transferred both by radiation and convection, but the radiation component is relatively small for the test conditions. When insulating materials are installed with single or multiple air spaces, Fig. 4. Curves Showing Relation Between Surface Conductances for Different Surfaces at 20 F Mean Temperature the position (vertical, horizontal or inclined) of the material and the direc tion of heat flow must be taken into consideration. For example, the re sistance to upward heat flow is about one-third the resistance to downward heat flow in a horizontal position (Table 1, Section C). The difference between the conductance through vertical air spaces and that through hor izontal and sloping air spaces with upward heat flow is considerably less. For upward heat flow, it is recommended that a value of 0.46 be used for the conductance of horizontal or sloping air spaces bounded on one side by reflective materials having an emissivity of approximately 0.05. The same conductance value is also recommended for similar vertical air spaces. When considering heat transfer to and from reflective surfaces in building construction, the emissivity should be known. This can be determined directly for the long wave length radiation corresponding to average room 180 CHAPTER 9 1954 Guide Table 5. Conductivities (fc) and Conductances (C) Used in Calculating Heat Transmission Coefficients (l/) in Tables 6 to 19 : These constants are expressed in Btu per (hour) {square foot) (Fahrenheit degree temperature difference). . Conductivities (k) are per inch thickness and conductances (C) are for thickness or . construction stated, noi per inch thickness CONDUCTIVITY B , Conductance Resistance Description. For- Per Inch Thick- Thiekneaa (0 (e)< (O neaa Listed AIR SPACES Bounded bt Ordinary Ma- TIB1AU.......................... _ Bounded btAluminumFoii. Vertical, 3 in. or more in width . Vertical, I in. or more m width. EXTERIOR FINISHES (Frame Walls) Brick Veneer.............;.................. Stucco (J in.)................................... Wood Shingles............................. Yellow Pine Lap Siding.:. 4 in. thick (nominal).. 1.10 0.46 12.50 1.28 1.28 0.91 2.17 0.44 0.78 0,78 INSULATING MATERIALS Aluminum Foil ....................... Bats and Blankets.................. Corkboard.............................. Insulating Board................ Mineral Wool...................... Vermiculite............................ See Air Spaces............................................ Made from mineral or vegetable fiber or animal hair, enclosed or open . . Purs, no added binder............................ Vegetable fiber............................................ Fiber made from rock, slag or glass... Expanded.................................................... .. 0.27 0.30 0.33 0.27 0.48 11 i.i i 3.70 3.33 3.03 3.70 2.08 - INTEBIOR FINISHES Composition Wallboard .. A in. to 3 in. thick............. .......... Gtpsum Plaster........................ GTPsdm Board (1 IN.)......... . Plain ot decorated . ........................ Gtpsum Lath (i in.) and Plaster thickness assumed 4 in.. Plaster............................................... Insulating Board (} in.)___ Plain or decorated........................... Inbulatino Board Lath (} in.) and Plaster.............. Insulating Board Lath (1 in.) and Plaster.............. Metal Lath and Plaster ... Plywood (8 in.)......................... Wood Lath and Plaster____ Plaster thickness assumed ) in.. Plaster thickness assumed ] in.. Plaster thickness assumed i in. Plain or decorated.......................... 0.50. 3.30 3.70 2.00 0.30 2.4 0.66 0.60 0.31 4.40 2.12 2.50, 0-27 0.42 1.52 1.67 3.18 0.23 0.47 0.40 MASONRY MATERIALS Brick........................................ ............ Brick.................................................... Brick . ................................................. Cement Mortar........................... 3 in. Clat Tile (Hollow) 4 in. Clat Tile (Hollow) 6 in. Clat Tile (Hollow) 8 in. Clat Tile (Hollow) 10 in. Clat Tile (Hollow! 12 in. Clat Tile (Hollow).. 16 in. Clat Tile (Hollow).. Concrete.......................................... .. Concrete. ........................................ 3 in. Concrete Blocks.......... 4 in. Concrete Blocks .'____ 8 in. Concrete Blocks 12 in. Concrete Blocks____ 8 in. Concrete Blocks .... 12 in. Concrete Blocks____ 8 in. Concrete Blocks____ 12 in. Concrete Blocks____ Gtpsum Fiber Concrete.. . 3 in. Gtpsum Tils................. 4 in. Gtpsum Tile.................... Stucco.................................................. Tile and Tbrbazzo................. Adobe, assumed 4 in..thick..... Common, assumed 4 m. thick. . Face, assumed 4 in. thick....... Light weight aggregate^...................... Sand and gravel aggregate................ Hollow, cinder aggregate...... ............. Hollow, cinder aggregate................. Hollow, gravel aggregate.................... Hollow gravel aggregate...................... Hollow, cinder aggregate............ . Hollow, cinder aggregate.................... Hollow,' light weight aggregate -- Hollow, light weight aggregate:... 874 percent gypsum and 124 perce wood chips.......................... '............... Hollow...................................................... Hollow.................... ................................. For flooring............................................ , __ 12.00 _ __ * __ . 2.50 12.00 -_ * __ _ t 1.66 *''' ` 12.50 . 12.00 . 12.50 0.89 1.25 2.30 __ 1.28 1.00 0.64 0.60 0.58 0.40 0.31 -- -- 1.28 1.00 1.00 0.80 0.60 0.53 0.50 0.47 _ 0.6! 0.46 -- -- __ -- 0.08 __ __ __ -- __ __ -- 0.40 0.08 __ __ _. - _- _. -- 0.60 -- -- 0.08 0.03 0.08 1.12 0.80 0.43 -- 0.78 1.00 1.57 K67 1.72 2.50 3.23 -- -- 0.78 1.00 1.00 1.25 1.66 1.88 2.00 2.13. -- 2.18 --; -- Stone.. ' downward*. Conductance values for horizontal air spaces depend on whether the heat flow is upward or but in most cases it is sufficiently accurate to use the same values for horizontal as for vertical air * Expanded slag, burned clay or pumice. Table 5. Conductivities (h) and Conductances (C) Used in Calculating Heat Transmission Coefficients (U) in Tables 6 to 19 These constants are expressed in Btu per <8out) (ayunre fool) {Farhenhsit degree temperature difference.) Conductivities (k) are per inch thickness and conductances (<7) are for thickness or construction stated, not per inch thickness ' ' .Conductivity or Conductance Resistance .. Material Description ROOFING MATERIALS Asbestos Shingles.................. Asphalt Shingles............. . Built-up Rooping..................... Heavy Roll Roofing Slate.................................... Wood Shingles......................... ' Assumed thickness ) in. Assumed 4 in............. SHEATHING Gypsum (i in.)................................ Insulating Board (|| in.) .. PLYWOOD (,* in.).......................... Fir or Yellow Pine (1 in:) . Fir, Plus Building Paper. - Actual thickness Ji in. ' Actual thickness jj| in.. SURFACES Still air....................................... 15 wph Wind Velocity .. Ordinary non-refleetive vertical............................... Ordinary non-reflective vertical.............................. WOODS FiaSHBATHINO (1 IN.) BUILD ING Paper and Yellow1, Pine Lap Siding............... Maple or Oak............... :........... Yej-low Pine or Fib................ j. materials, materials. (*) 1.15 0.80 Per Inch: For Thick Thick- <C) ness G) (e) 6.00 6.50 3.53 6.50 20.00 1.28 2.82 0.42 2.56 1.02 0.86 1.65 6.00 0.17 0.15 0.28 0.15 0.05 0.78 0.35 2.37 0.39 0.98 1.16 0.61 0.17 0.50 0.87 1.25 and wall temperatures. The possibility of change in emissivity with time of exposure due to surface coatings, chemical action, deposition of dust, etc., must be considered in selecting a material for use.10 PRACTICAL COEFFICIENTS AND THEIR USE . . For practical purposes it is necessary to have average coefficients that may be applied to various materials and types or construction without the necessity of making actual tests. In Table 2 coefficients are given for a group of materials which have been selected from tests by various author ities. Since there is some variation in the resulting values due to varia tions in materials and in test conditions, average values for the usual ^con ditions encountered in building practice have been selected and listed in Table 5. These coefficients were used in the calculation of overall coeffi cients given in Tables 7 to 19. These tables, constitute typical examples of combinations frequently used, but any special constructions not given can be computed by the use of the conductivity or conductance values in Table 2 and the fundamental heat transfer formulas. Caution The user should realize that the average conductivity and conductance values given in Tables 2 or 5 do not necessarily apply to all products of the same general description. In using these values, judgment should be exer cised with regard to the extent to which the product (either as received or as 182 CHAPTER 9 1954 Guide Table 6. Coefficients of Transmission (JJ) of Frame Walls and Roofs with Insulation Between Framing0 ` Coefficients are expressed inBtu per (Aottr) {square foot) {Fahrenheit degree difference in temperature between the air on the two sides), and are based on an outside wind velocity of 16 mph. COEFFICIENT WITH INSULATION BETWEEN FRAMING a-'* I COEFFICIENT WITH NO insulation between framing 0.11 0.13 0.15 0.17 0.19 0.21 0.23 0.25 0.27 0.29 0.31 0.33 0.35 0.37 0.39 0.41 0.43 Mineral Wool or Vegetable Fibers in Blanket or Bat Form6 (Thickness below) 1 IN. A 0.078 0.088 0.097 0.10 0.11 0.12 0.12 0.13 0.14 0.14 0.14 0.15 0.15 0.16 0.16 0.16 0.17 2 in. B 0.063 0.070 0.075 0.080 0.084 0.088 0.091 0.094 0.097 0.10 0.10 0.10 0.11 0.11 o.n 0.11 0.11 A 0.054 0.058 0.062 0.066 0.069 0.072 0.074 0.076 0.078 0.080 0.081 0.083 0.084 0.085 0.086 0.087 0.088 " l^oemcieiiua wjicovcm - -- - _______ .. r 6 Based on one air space between framing. * No air space* 3|IN. Mineral Wool between Framing* 0.051 0.055 0.059 0.062 0.065 0.067 0.069 0.071 0.073 0.075 0.076 0.077 0.078 0.080 0.081 0.082 0.082 . : l applied) will comply with the tabulated values. Exact conductivities or j conductances for specific materials should be obtained from the maker. i Insulating Materials . 1 In order to determine the benefit derived from the addition of insulating ) materials to a given construction, the overall coefficient of heat transmis- ' sion Ui of the insulated construction may be compared with the corre- ' sponding coefficient U without insulation. Table 6 may be used for de- , termining the coefficients of transmission of frame constructions with the ; types and thicknesses of insulation indicated in Columns A to D inclusive * between framing. Columns A, B and C may be used for walls, ceilings ' or roofs with only one air space between framing but are riot applicable to i ceilings with no flooring above (See Table 12). Column D is applicable to walls only. - Example: Find the coefficient of transmission of a. frame wall consisting of wood siding, I) in. insulating board sheathing, studs, gypsum lath and plaster, with 2 in. ! blanket insulation between studs. According to Table 7, a wall of this construction ; with no insulation between studs has a coefficient of 0.19 (Wall No. 4D). Referring to Column B above, it will be found that a wall of this value with 2 in. blanket in- - sulation between the studs has a coefficient of 0.084. ( Attention is called to the necessity of applying the insulating material , in accordance with the manufacturer's specification. The engineer must evaluate carefully the economic considerations involved in the selection of an insulating material as adapted to various building constructions. Lack of proper evaluation, or improper installation may lead to unsatis- . factory results. Special attention must be given to vapor barriers as out-' lined in Chapter 10. Water-soaked, insulation loses its effectiveness as insulation. . ., n Heat Transmission Coefficients of Budding Materials 183 Computed Heat Transmission Coefficients - Computed overall heat transmission coefficients of many common types of building construction are given in Tables 7 to 21, inclusive, each coeffi cient being identified by .a serial number, except in Tables 19, 20, and 21. For example, the coefficient U of a brick veneer, frame wall with wood sheathing and j-in. of plaster on gypsum lath is 0.27 (Wall No, 28-C in Table 7) and with 2 inches of blanket or bat insulation, the coefficient would be 0.097 (No. 49-B in Table 6). . . In the analysis of any wall construction for the purpose of calculating the overall coefficient of heat transmission U, it is first necessary to deter mine the paths of heat flow, that is, whether they are parallel or series, or a combination of both. This is in accordance with the basic laws of heat Fig. 5. Section of Concrete Wall Having Steel Aie Rods and Insulation 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 over-emphasized. 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 2 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 2: Calculate the coefficient of heat transmission U for a wall shown in rig. 5. Wall construction consists of two 4-in. concrete walls separated by a 2$-in. space filled with insulation; J-m- diameter metal tie rods are imbedded a distance of f in. in each 4-in. concrete wall, and spaced 9 in. vertically and 12 in. horizontally. Values of k are: insulation 0.30, concrete 12.00, tie rods 400.00. Solution: In Fie. 5 the following paths of heat flow from plane A to plane F will be noted: L From A to B: One path through 3 in. of concrete, cone Two paths, (a) through 1 in. of tie rod, and (b) through 1 in. of * -v 184 CHAPTER 9 1054 Guide 3. From C to D': Two paths, (a) through 2J in. of tie rod, and (6) through 2j in. of insulation. . 1 4. From D to E: Two paths, (a) through 1 in. of tie rod, and (b) through 1 in. of concrete. ' 5. From E to F: One path through 3 in. of concrete. I . 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 difference 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'niade by:assuming that no heat transfer takes place between the metal tie.rod and , the surrounding materials. Although the pattern of the isotherms is unknown, the following method of calculation does partially take into;account the heat flow be tween the metal tie rods and its bounding materials. Parallel Flow. The conductances through the areas of parallel heat flow may be determined as follows: 1. The area of each }-in. diameter tie rod is 0.00036 sq ft, and as the tie rods are spaced 9 in. vertically, and 12 in. horizontally, there will be 0.00036 X i = 0.00048 sq ft of tie rod to each square foot of wall area. Then from plane B to plane C, the conductance C\ is 0.00048 400 0.99952 12 Cl = x To + To" xIo = 0192 + 11994 " 12186 2. For tie rod and insulation from plane C to plane D the conductance C% is ,, 0.00048 400 0.99952 0.30 ^ c' = ~LfT x 25 + ~U~ x ij = 0 077 + 0120 = 0197 3. For tie rod and concrete from plane D to plane E the conductance Ci is ,, 0.00048 400 0.99952 12 ,, c' = "15" x To + "TT x 15 = -192 +11994 " 12186 Series Flow. After the conductance values have been determined, the total re sistance and If value can be determined as follows: ,,1 1 1 1 x2 1 . ' fi h Oi Cs Cs ks fo 1 ,M V- + --1--|--:--u 3.0 -- + -- Bt - 1.65 + 12.0 + 12.186 ^ 0.197 12.186 12.0 6.0 . Rt = 0.606 + 0.250 + 0.0821 + 5.076 + 0.0821 + 0.250 + 0.167 = 6.513 7 V = -g- = = 0.153 Btu per (hr) feq ft) (F deg). n? o.51o ' The Hot Box test value, from University of Minnesota, for this wall, i) corrected for a 15 mph wind velocity, was U = 0.150 Btu per (hr) (sq ft).-/1 (F deg). The error between the calculated and test values would be . "i; 0.153 - 0.150 X 100 = 2 percent. 0.150 If the effect of the tie rods were omitted from the calculations, the overr7, all U value would be 0.103. Although the percentage of area occupied by V 0 00048 ,1 the1 tie rods per square foot of wall area is------ x 100 = 0.048 percent, Heat Transmission Coefficients of Building Materials 185 the error between the calculated and test values would be 0.150 - 0.103 0.150 X 100 31 percent. In making the calculations for values of U shown in Tables 7 to 19, the following conditions have been assumed: Equilibrium or steady-state heat transfer, eliminating effects of heat capacity. ' Surrounding surfaces at ambient air temperatures. . Exterior wind velocity of 15 mph. Surface emissivity of ordinary building materials = 0.83. No correction for position or direction of heat flow. (Average coefficients used). Air spaces are f in. or more in width. Variation of conductivity with mean temperature neglected. Corrections for framing made on basis of parallel heat flow through 2 X 4 in. (nomi nal) studs, 16 in. on centers, the framing covering 15 percent of wall area. Actual thicknesses of lumber assumed to be as follows: Nominal Actual 1 in. (S-2-S)................................. Min. li in. (S-2-S)................................. lA in. 2 in. (S-2-S)..:.._.......................If in. 21 in. (S-2-S)..............7................ 2f in. Nominal Actual 3 in. fS-2-S)..........................................2f in. 4 in. (S-2-S)...........................................3$ in. Finish flooring, (maple or oak).. .Iff in. Coefficients for frame construction are corrected for the effect of framing where such correction would increase the coefficients, but not where the correction would decrease the coefficients.11 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 becomes 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. Some engineers do not use a 17value less than 0.10. n Roof Coefficients Computations for wood shingle roofs applied over wood stripping are based on 1 by 4 in. wood strips, spaced 2 in. apart. Values for roofs con taining Spanish and French clay roofing tile are assumed the same as for slate roofs. Values for pitched roofs in Table 17 apply where the roof is over a heated attic or top floor, so that the heat passes directly through the roof structure, including any interior finish material. Combined Ceiling and Roof Coefficients If the attic space between the ceiling and roof is unheated and not venti lated, the combined coefficient from room air below the ceiling to exterior air can be calculated from the following formula: : and where JJ Ry Bt = U--,, +T n--U, U = 1/Bt combined coefficient to be used with ceiling area, total resistance of ceiling and roof. (4) (5) CHAPTER 9 1954 Guide Ua = 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 by the roof area. Values of XJt and Uce should be calculated using a value of 2.2 (the reciprocal of one-half the air space resistance) rather than 1.65 for the conductances of surfaces facing the attic, since the attic is 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, multiplied by its percentage of the total area, should be used as Ur Where attic wall areas are large, 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 Uce for the ceiling by the difference in temperature above and below the ceiling. I, 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 constituting the wall or floor, and on the conductivity of the surrounding earth. The conductivity of the earth will vary with local conditions, and is usually unknown. Tests12 at the A.S.H.V.E. Research Laboratory indicate a heat flow of approximately 2.0 Btu per (hr) (sq ft) through an uninsulated concrete basement floor, with a temperature difference of 20 F between ground temperature and the air temperature 6 in. above the floor. Based on this result a coeffi cient of 0.10 Btu per (hr) (sq ft) (Fahrenheit degree difference) is recom mended for calculation where it is desirable to allow for the small base ment floor heat loss, e.g., for heated basements. For basement walls the same coefficient may be used, but due to closer proximity to the surface of the ground, the temperature difference for win ter design conditions will be greater than for the floor. The test results indicate a unit area heat loss, at mid-height of the basement wall approxi mately twice that of the same floor area. For concrete slab floors laid in contact with the ground at grade level, recent tests1* indicate that for small floor areas (equal to 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) (lineal foot of exposed edge) (Fahrenheit degree difference between the inside air temperature and the average outside air temperature). It should be noted that this may be appreciably reduced by insulating under the ground slab, and also along the edges between the floor and the abut ting walls. See also sections on Basement Temperatures and Heat Loss, and on Floor Heat Loss in Basementless Houses, in Chapter 12. In most calculations if the perimeter loss is calculated accurately, no other floor loss need be considered. Glass Coefficients The U values for glass sheets and hollow glass block, given in Sections A, B and G of Table 20, have been computed by methods and data given in an A.S.H.V.E. Research Paper.14 It is assumed that the surface.conduct ance for convection loss to the air is 4.0 Btu per (hr) (sq ft) (F deg). It `p 183- l , f'urrfngTM"Ined| M " lh`c*k ' f studdine neglected. except wd. QTable 8. Coefficients of Transmission (U) of Masonbt. Walls Coefficients are expressed in Btu per (hour) (square foot') {Fahrenheit degree difference *n temperature between the air on the two sides), and are based on an outside wind velocity of IS mph. ' FTWTflR I Heat Transmission Coefficients of Building Materials 189 Table 9. Coefficients op Transmission (U) of Brick and Stone Veneer Masonht Walls Coefficients are expressed in Btu per (Hour) (square foot) {Fahrenheit degree difference in temperature betineen the air on the two sides), and are bn**d on zr. outside wind velocity of IS mph. TYPICAL CONSTRUCTION FACING BACKINO INTERIOR FINISH (Purs Insulation Wssbb Indicated) | & 23i & !l a f 11 P i1 JB i ao 'd 3 5 1 s 3 4 3 a I 5 i 1 3 3 i s 5 3* l K*| 3 3. If ij 1| 11 m% f! a 4 ll-ls S3 Zl d !| jm If O1 C*. jj* II 2 53 1 A B cDE FGH 1 8 In. HollowTIW..-.................... ----- 055 034 075 055 054 0.19 0.18 014 on Rfl 054 052 055 054 053 0.19 058 0.14 0.13 89 3f\*;i b 4 In. Brick Veneer* . fihvIVmrrttfe...... . _ ......... filn. Concrete------------ ........... 058 054 035 055 033 0.24 053 ai? 0.15 90 054 050 053 053 051 053 053 0J7 0.16 91 5 8 In. ConcreteBlocks* (Gravel Aggregate!....... ......... 0.44 0.41 059 059 058 051 051 0.16 0.14 92 8 In. ConcreteBlocks* 8 In. Concrete Blocks* 054 053 055 054 054 0.10 0.18 0.14 0.13 83 (LightWeightAggregata)4_-r,_ 051 059 053 053 052 0.18 0.17 0.14 0.12 94 6 In. Hollow TOe6 8ta HollowTil* 0,37 035 056 056 0.25 019 0.19 015 0.13 98 056 054 055 055 054 0.19 0.19 0.14 0.13 98 (SBTeaehsetee8dxintopn. a.4n1di8n31..0)hinar.dtilberfiicgkuraensdarreebmaasienddoenr ctwomo cmeollsnibnrtihcek.direction of heat flow. The 12 in. tile is base.d^ Dn three cells in the direction of heat flow. The 16 in. tile consists of one 10 in. and one 6 in. tile, each having.'j' two cells in the direction of heat flow. ^ c Limestone or sandstone. * These figures may be used with sufficient accuracy for concrete walls with stucco exterior finish. * * Expanded slag, burned clay or pumice. ' * Thickness of plaster assumed ) in. 9 Thickness of plaster assumed i in. '{ ,'C ' - ~ *--:--one air space, . . --''f<t i-. y0 4 In. Cut Stone Veneer* 6 la Concrete. 8 In. nonerrfa...... ........ ............. 063 058 057 056 054 055 024 0.18 0.15 97 057 053 055 054 053 054 053 0J7 0J5 88 S! 1* 8 bv Concrete Blocks* (Gravel Aggregate)-------^-------- 0.47 0.44 050 050 059 052 051 0.16 0.14 99 8In. Concrete Blocks* (Cinder Aggregate),...,.... 056 054 055 055 054 0.19 0.19 0.15 0.13 100 8 In. Concrete Blocks* (Light WeightAggregateH___ ,_ 052 050 053 053 052 0.18 0.17 0.14 0.12 101 (See text p. 183.) -. . * Calculation based on \ in. cement mortar between backing and facing, except in the case of the concrete backing which is assumed to be poured in place. 6 The hollow tile figures are based on two air cells in the direction of heat flow. Hollow concrete blocks. Expanded slag, burned clay or pumice. ^"Thickness of plaster assumed } in. Thickness of plaster assumed 4 in. Based on 2 in. furring strips; one air space. 190 CHAPTER 9 1954 Guide Table 10. .Coefficients of Transmission ({/) of Frame Partitions or Interior Walls" Coefficients are expressed in Btu per (hour) (square foot) (Fahrenheit degree difference in temperature between the air on the (too sides), and are based on still air (no wind) conditions on both sides. INTERIOR FINISH Intrrtw finish 'i I P^J SINGLE partition (Finish on one side only of studs) DOUBLE PARTITION (Finish on both sides of studs) NO INSULATION BETWEEN STUDS 1 in. Blanket* BETWEEN STUDS. One alb space. Wood Lath and Plaster Gypsum Latb (H hi.) Plastered*, a----------- -------- Plywood (H In.) Plain or Decorated.-- .. Insulating Board (H in.) Plus or Decorated^TM.... Insulating Board Lath in.) Plastered*__ Insulating Board Lath (1 m.) Plastered*.. A 0.09 0.67 0.62 0.61 0.59 0.36 0.35 023 B ' 059 057 054 034 053 0.19 0.18 0J2 C 0.16 0.16 0.15 0.15 0.15 0.11 0.1] 0082 a J Xo E s a<. 1 2 3 4 5 6 7 8 (See text p. 183.) Coefficients not weighted; effect of studding neglected. 1 j- . 6 Plaster assumed 3 in. thick.. . '` e Plaster assumed \ in. thick. * For partitions with other insulations between studs refer to Table 6, using values in Column B of above table, in left-hand column of Table 6. Example: What is the coefficient of transmission (U) of a partition consisting of gypsum lath and plaster on both sides of studs with 2 in. blanket between studs? Solution; -%; According to above table, this partition with no insulation between studs (No. 4B) has a coefficient of 0.34. 4 Referring to Table 6, it will be found that a wall having a coefficient of 0.34 with no insulation between studs. will have a coefficient of 0.10 with 2 in. of blanket insulation between studs (No. 56B). Heat Transmission Coefficients of Building Materials 192 CHAPTER 9 1954 Guide 13. U)Table Coefficients of Transmission ( of Concrete Construction Floors and Ceilings ' Coefficienta are expressed in Btu per (hour) (square foot) (Fahrenheit degree difference in temperature between the air on the two sides), and are based on still air (no wind) conditions on both sides. TYPE OF CEILING Typ E OF FLOO EUNO Thickness No of Flooring Concrete (Concrete (Inches) Bare) . Tile0 or Terra*zo Flooring on Concrete H In. Asphalt Tile* Directly on Concrete Parquett* Flooring in Mastic on Concrete Double Wood Floor on j Sleepera0 a0 a pa fc ABC DE H in. Plaster Applied to Underside of Concrete............................................. Metal Lath and Piaster0--Suspended or Furred........................................... Gypsum Board (% in.) and Plaster^-- Suspended or Furred....................... Insulating Board Lath (H in.) and Plaster-^--Suspended or Furred___ 6 10 3 6 10 3 6 10 3 6 10 3 6 10 0.59 0.50 0.62 0.54 0.46 0.38 0.35 0.32 0.36 0.33 0.30 0.25 0.23 0.22 0.65 0.56 0.48 0.59 0.52 0.44 0.37 0.34 0.31 0.35 0.32 0.29 0.24 0.23 0.21 0.66 0.58 0.49 0.60 0.53 0.45 0.37 0.35 0.32 0,35 0.33 0.30 0.25 0.23 0.22 0.45 0.41 0.36 0.43 0.39 0.34 0.30 0.28 0.26 0.28 0.27 0.24 0.21 0.20 0.19 0.25 0.23 0.22 0.24 0.22 0.21 0.19 0.18 0.17 0.19 0.18 0;17 0.15 0.15 0.14 l 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Thickness of tile assumed to be 1 in. 6 Conductivity of asphalt tile assumed to be 3.1. c Thickness of wood assumed to be in.; thickness of mastic, i in. (h * 4.5). Col. D may afro be used for concrete covered with carpet. . ' .' * Based on J$ in. yellow pine or fir sub-flooring and 13 in.,hardwood finish flooring with an air space between sub-floor and concrete. * Thickness of plaster assumed to be 3 in. S Thickness of plaster assumed to be 3 in. 0 For other thickness of concrete, interpolate. Table 14. Coefficients of Transmission (XJ) of Concrete Basement Floors on Ground with Various Types of Finish Flooring^ U = 0.10* Btu per (hr) (sq ft) (Fahrenheit degree temperature difference between the ground and the air over the floor). 0 Since authentic data are not available, this coefficient is sometimes used for concrete floors on ground. For more recent procedures1* refer to National Bureau of Standards Report BMS-103. is also assumed that the glass loses heat by radiation to the ground and to the clear sky, which together have an effective radiating 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 which is used in the usual manner. The equivalent surface conductance for radiation and convection combined, based on airlo-svrface temperature difference, therefore varies from about 5.5 for sin gle glass to about 6.6 for double glass for exactly the same environmental design conditions. It is assumed that the room air temperature equals the average tem perature of the room surfaces seen by the glass. Special consideration .should be given to those cases where the glass sees interior surfaces at H,,l TM-**. Cfwfficient, of Bwrtta, 193 (See Tabic 16 for Flat Roofs with Ceilings) These coefficients are expressed, in Btu per (hour) (square foot) (Fahrenheit degree difference in temperature bttween the air on the two sides), and are based on on outside wind velocity of tS mph. ; -- ; - r- Ttpb of Roof Decs Fkt Metal Root Deck0 . /(CrO>V^IBavELDA1t^oolht IWUow Top of Dun Thick- |noi.| J 2t%88 OF SOLU Roof TION laS, nraroAnsaBoABD . (Thickness Below) [ i In. 1 In. ljln. 2 In- Corkboab (Thickness Below) Non. sea 1 In. Hln. 2 In. I B C D E|p G 0.94 0.39 0.24 0.18 0.14 I 0.23 0.17 Precast Cement Tile 'ire- 0.84 0.3 0.24 0.17 I 0-14 I 0.22 0.16 Concrete 2 in. <" 0.82 0.36 0.72 0.34 0.65 0.33 0.24 00..2223 0.17 0.17 0.16 0.14 0.13 0.13 0.23 0.21 0.21 0.16 0.16 0.15 0.13 00..1122 "SYS ?iber Concrete* t m. Gypaum Board Wood0 mmKf`ULa>n/ | fa* i in. 0:38 0.31 00..2214 0.18 0.16 0.14 0.13 00..1112 0.17 I 0.13 0.15 0.12 0.11 0.10 in. in. 2 in. J- Sil 0.32 023 0.28 .24 0.22 0M 0 20 0.17 o> Q.'ll 0.15 0.14 00..1113 o0..1n2 0.11 0.10 0.17 0.16 0.095 I 0.13 0.14 0.13 0.12 0.11 00..1113 0.10 0.091 8 9 10 11 ^ ^ 1,68 Btu outside wind^velocity Csq ft of Projected 87* Percent gypsum, 12} 1 Percent wood fiber. Thickness indicated i; cNoi rerea) thicknesses specified-actual thicknesses need in includes calcuintious. } in. gypsum board. CHAPTER 9 Table 16. Coefficients of Transmission (t7) of Flat Roofs: Covered with Built-up Roofing. With Lath and Plaster ,Ceilings" . (See Table 15 for Flat Roofs with No Ceilings) These coefficient* are expressed in Bin per (hour) (square foot) (Fahrenheit degree difference in temperature between the air on the two sides), and are based on an outside wind velocity of 16 mpk.. , - Type or Roop Deck Insulation on Top or Deck (Covered with Built-Up Hooping; Thick ness or Roor Deck (Inches) No In sola tion Insulating Board (Thickness Below) fin. If In. 2 In. D CORKBOABD (Thickness Below) If In. 2 In. H Fist Metal Roof Deck tKXTUTWri/ jffl.Sn.mit "gjl rtSTAU*1 T a b l e 17. C o e f f ic ie n t s o f T r a n s m is s ic Coefficients are expressed in B tu per (hour) (square fo o t) (Fahren the a ir on the two sides), and are based on an out* Precast Cement Tile CLtUKfi' Concrete (LeoriHWS/Oj L&TIOM// <^HCH tTt ' 1 il *1 If in. 2 in. 4 in. 6 in. 0.42 0.40 0.37 0.26 0.25 0.24 0.19 0.18 0.18 0.14 0.14 0.14 0.12 0.12 O'. 11 0.18 0.17 0.17 0.14 0.13 0.13 0.11 0:12 0.11 Gypaum Fiber Concrete5 on 4 io- Gypaum Board 2SOPrPiIlnHHeg/xU*. Lfttlfli i.iimra eipjv*. Ci tU-`lHd '} -l !J in. 1} tn. 0.27 0.23 0.19 0.17 0.15 0.14 0.12 0.11 0.10 0.14 0.097 0.13 0.12 0.11 0.097 0.091 m Wood* MmATifti; 1 in. If in. 2 in. 3 in. 0.31 0.26 0.24 0.18 0.21 0.19 0.17 0.14 0.16 0.15 0.14 0.12 00..1132 0.11 0.10 0.11 0.15 0.10 0.14 0.097 0.087 00..1131 00..1121 0.10 0.095 0.11 0.092 0.095 0.082 m ii i i. . . ._______________ Calculations based on metal lath and piaster ceilings, but coefficients may be used with sufficient curacy for gypsum lath or wood lath and plaster ceilings. It is assumed that there is an air space betweegpjl the5u8n7dVerpseidrceeonft tghyeprsouomf ,d1ec2k^ apnedrctehnet uwpopoedr fsibideer. ofThthicekcneeislisngin. dicated includes 4 '. gypsum board. e Nominal thicknesses specified--actual thicknesses used in calculations. ,-&i Ii ,1954 Guide (U)Table 18. Combined Coefficients of Transmission of Unvented Pitched Roofs* and Horizontal Ceilings--Based on Ceiling Area1 Coefficient* are expressed tn Btu pe r (hour) (square foot of ceiling areo) (Fahrenheit degree difference in temperature between the air on the two sides), and are based on an outside wind velocity of 15 mph. Ttfb of Roofing and Roof Sheathing Coefficients (From Table 12) Wood Shingles on Wood Stbifs4* Insulation (Rafters (Ur 0.48) 1 In. Insu- lating Board lating Board on Under Side on Under Side of Rafters of Rafters (Ur = 0.22) (Ur - 0.16) Asphalt Shingles* ob Roll Roofing on Wood Sheathing* No Roof Insulation (Rafters Exposed) (Ur = 0.53) H In. Insu- 1 In. Insulating Board lating Board on Under Side on Under Side of Rafters of Rafters (Ur * 0.23) (Ur - 0.17) H ca 1 Z :v,\ AB C D EF 0.M 0.19 0.24 0.29 6.37 0.69 0.085 0.092 0.099 o.n o.n 0.12 0.13 0.13 0.14 0.14 0.15 0.15 0.16 0.16 0.17 0.17 0.18 0.18 0.-19 0.19 0.20 0.21 0.22 0.22 0.23 0.25 0.29 0.29 0.30 0.31 0.31 0.073 0.078 0.082 0.087 . 0.091 0.096 0.10 0.10 0.11 0.11 o.n 0.12 0.12 0.12 0.13 0,13 0.13 0.13 0.14 0.14 0.14 0.15 0.15 0.15 0.15 0.17 0.18 0.18 0.19 0.19 0.19 0.066 0.07 0.074 0,078 0.081 0.084 0.087 0.090 0.093 0.095 0.098 0.10 0.10 0.10 0.11 0.11 0.11 0.11 0.12 0.12 0.12 0.12 0.13 0,13 0.13 0.13 0.14 0.15 0.15 0.15 0.15 0.087 0.094 0.10 0.11 0.11 0.12 0.13 0.13 0.14 0.15 0.15 0.16 0.17 0.17 0.18 0.18 0.19 0.19 0.19 0.20 . 0.20 0.22 0.22 0.23 0.23 0.26 0.30 0.31 0.31 0.33 0.33 0.074 0.079 0.083 0.088 0.093 - 0.097 0.10 0.10 0.11 0.11 - 0.12 0.12 0.12 0.12 0.12 0.13 0.13 0.13 0.14 0.14 0.14 0.15 0.15 0.15 - 0.16 0.17 0.19 0.19 0.19 0.20 0.20 0.067 0.071 0.075 0.079 0.083 0.086 0.089 . 0.092 0.095 0.098 0.10 0.10 0.11 0.11 o.n o.n o.n 0.12 0.13 0.12 0.12 0.13 0.13 0.13 0.13 0.14 0.15 0.15 0.15 0.16 - 0.16 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 (See text on p. 185.) Calculations based on i pitch roof (n 1.2) using the following formula: : / ,, Ut X (fee V = combined coefficient to be used with ceiling area. "" Ur -- coefficient of transmission of the roof. . Ut H------- Uee * coefficient of transmission o! the ceiling. n n = the ratio of the area of the roof to the area of the oeiling. ' : Use ceiling area (not roof area) with these coefficients. -' c Coefficients in Columns D, E and F may be used with sufficient accuracy for tile, slate and rigid as- , bestos shingles on wood sheating. * Based on 1 x A in. strips spaced 2 in, apart. . .' Sheathing assumed Jf in. thick. '' f Values of Uee to be used in this column may be selected from Table 12. ' & temperatures differing greatly from the room air temperature, t.e., such > cases as in sun rooms, greenhouses, and some panel heated rooms, or a 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 20 values, consideration of the dependence of ^ the indoor surface conductances upon temperature and direction of heat^ j ( )UTable 19. Coefficients of Transmission of Solid Wood Doors dents are expressed in Btu per (hour) (sonar* NOMTNAT, Inches 9 and are based u Actual j. sickness Inches -. * ..--uegree atfference in temperature between i on outside wind velocity of 15 mph. 1' Ija.b Exposed Doos ' , Uttr b . With Glass StobmDoob i if H i* 0.69 0.59 0.35 IfH lTV . 0.52 : 0.51 0.32 0.30 0.30 2 2i if 2i 0.46 0.28 2f 0.38 0.25 Computed using k =* 1,_15__fo_r_w_o_o_d_, f_i_=_*_1_.65i, fe * 6.0, 0.33 and M0 for air space. _0_._2_3___ I- * A U value of 0.85 may be used for single exposed doors containing thin wood panels or single panes of glass, and 0.39 for the same with glass storm doors. ' * 50 percent glass and thin wood panels. ( )UTable 20. Coefficients of Transmission of Windows, Skylights and Glass Block Walls Coeffic-*ie nitts* are expressed in Btu per (hour) (square foot) (Fahrenheit degree difference in temperature between the aiirr on the two sides), ana are based upon the following outdoor conditions: 0 F air temperature, ' clear skies, no solar radiation -Section A-Vebticai. Glass Sheene Number op Sheets Glass Sheet, (heat Ihfl;*} m1- `Wet.... Ill i Ilf " Click.. . U ?.3-* " Ifaick.. Section C--Walls op Hollow Glass Blocs Description Mhltiplt Flat'g^ Window Description u 0.60 0.56 0.62 0.48 (See text p. igg.) . . b *or 1 in. or greater. ei'Tro"1 unpublished data recommended by ASHVE Tech. Adv, Comm, on Glass. d ttD1' tyPe double glazing (two lights or panes in same opening). , ^ values for two sheets with 1 in. air apace. / on area of exposed portion of sash; does not include frame or portions of sash concealed by frame. . or metal storm sash or metal sash with attached storm pane. . 198 CHAPTER 9 1954 Guide 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 1.65 used in computing U values given in other tables in this chapter. These values should therefore be used in estimating the tem perature at which condensation on glass surfaces will occur. The application factors given in Section D of Table 20 are based upon hot box tests summarized in a research bulletin16, and are approximate only. In practice, some variation in heat flow through windows having Table 21. Conversion Table fob Wall Coefficient U for Various Wind Velocities # U FOR 0 TO 30 MFH WlND VELOCITIES V FOR 15 MPH" 0 5 10 20 25 0.050 .0.060 0.070 0.080 0.090 0.100 0.110 0.130 0.150 0.170 00..129100 0.230 0.250 0.270 0.290 0.310 0.330 0.350 0.370 0.390 0.410 0.430 0.450 0.500 0.600 0.700 0.800 0.900 1.000 1.100 1.200 1' .300" 0.049 0.059 0:068 0.078 0.087 0.096 0.105 0.123 0.141 0.158 0.175 0.192 0.209 0.226 0.241 0.257 0.273 0.283 0.303 0.318 0.333 0.347 0.362 0.376 0.410 0.474 0.535 0.592 0.645 0.695 0.742 0.786 1 0.828 0.050 0.059 0.069 0.079 0.089 0.099 0.108 0.127 0.147 0.166 i 0.J84 0.203 0.222 0.241 0.259 0.278 0.296 0.314 0.332 0-350 0.368 0.385 0.403 0.420 0.464 0.548 0-631 - 0.711 0.789 0.865 0.939 1.010 , 1.080 0.050 0.060 0.070 0.080 0.090 0.100 0.109 0.129 0.149 0.169 0.188 0.208 0.227 0-247 0.266 0.286 0.305 0.324 0.344 0.363 0.382 0.402 0.421 0.439 0.487 0.581 0.675 0.766 0.858 0.949 1.039 1.129 1.217 0.050 0.060 0.070 0.080 0.090 0.100 o.no 0.131 0.151 0.171 . 0.191 0.212 0.232 0.252 0.273 0.293 0.313 0.333 0.354 0.375 0.395 0.416 0.436 0.457 0.509 0-612 0.716 0.821 0.927 1.034 1.142 1.250 1.359 0.050 0.060 0.070 0.080 0.091 0.101 o.in 0.131 0.151 0.172 0.192 0.213 0.233 0.253 0.274 0.295 0.315 0.336 0.357 0.378 0.399 0.420 0.441 0.462 0.514 0..620 0.728 0.836 0.946 1.058 ' 1.170 1.285 1.400 U in first column is from previous tables or as calculated for 15 tnph wind velocity. 30 0.050 0.060 0.070 0.080 0.091 0.101 o.in 0.131 0.152 0.172 0.193 0.213 0.234 0.254 0.275 0.296 0.317 0.338 0-359 0.380 0.401 0.422 0.444 0.465 0.518 0.626 0.736 0-847 0.960 1.075 1.192 j 11..433108 the same ratio of glass to sash area, may be expected because of difference ijl in construction details and in air space edge effects. J Wind Velocity Correction for t/-Values i* Tables 7 to 9, and 15 to 19, present values of U for walls and other sur-A faces based on an outside wind velocity of 15 mph. Table 21 shows com-/j| parative values of U lor other wind velocities. , '' Example S: Find the coefficient of transmission U of a frame wall consisting of /: wood siding, ff-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. T Solution: From Table 7, Wall No. 40, with no insulation between studs has a value of V = 0.19. From Table 6, Co). B, this wall with 2-in. insulation added has a value Heat Transmission Coefficients of Building Materials 199 of U -- 0.084. Entering Table 21 in the 15 mph column, interpolate between 0.080 and 0.090 in 15 mph column and proceed horizontally to the 25 mph column where the (/-value is found by interpolation to be 0.085. .......; CALCULATING SURFACE TEMPERATURES - In many heating and cooling load calculations it is necessary to deterT mine the inside surface temperature or the temperature of the surfaces within the structure. As the resistance of any path of heat flow is ex pressed in Fahrenheit degrees per (Btu) (hour) (square foot), the re sistances through any two paths of heat flow would be proportional to the temperature drop through these paths, and can be expressed as follows: where . - . - A) Rt <,-.) m w Ri = the resistance from the inside air to any point in the structure at which the temperature is to be determined. Ri -- the overall resistance of the wall from inside air to outside air. ti -- inside air temperature. . U = temperature to be determined, t, = outside air temperature. Example 4: Determine the inside surface temperature for a wall having an overall coefficient of heat transmission U = 0.25, inside air temperature 70 F, outside air temperature --20 F. Solution: Then, by Equation 6 Hi = Iff, = 1/1.65 = 0.606 R, = l/V = 1/0.25 = 4.00 0 606 _ 70 - U 4.00 " 70 - (--20) t, = 56.4 F The same procedure can be used for determining the temperature at any point within the structure. A chart for determining inside wall surface temperature is given in Fig. 12 of Chapter 24, Panel Heating. . REFERENCES 1 Standard Method of Test for Thermal Conductivity by Means of the Guarded Hot Plate, sponsored bv A.S.H.V.E., A.S.T.M., A.S.R.E., and N.R.C., and approved as a Tentative Code by A.S.H.V.E. and A.S.T.M. in 1942 (A.S.T.M. designation C-177-45) Approved 1945). 'Heat Transmission Through Building Materials, by F. B. Rowley and A. B. p 1 D (University of Minnesota, Engineering Experiment Station Bulletin, No. 8, . 'Thermal Properties of Soils, by Miles S. Kersten (University of Minnesota, En gineering Experiment Station Bulletin No. 28, June 1949). 'Radiation and Convection from Surfaces in Various Positions, by G. B. Wilkes id C. M. F. Peterson (A.S.H.V.E. Transactions, Vol. 44, 1938, p. 513). tt Radiation Corrections for Basic Constants Used in the Design of All Types of Voe1a; t5in1g, 1S9y4s5t,emp.s2, 1b3y).B. F. Raker and F. W. Hutchinson (A.S.H.V.E. Transactions, 200 CHAPTER 9 , . * A.S.H.V.E. Reseabch RepobtNo. 869--Surface Conductances as Affected by Air Velocity, Temperature and Character of Surface, by F. B. Rowley, A. B. Algren and J. L. Blackshaw (A.S.H.V.E. Tbansactions, Vol. 36, 1930, p. 444). 7 Forced Convection Heat Transfer from Flat Surfaces, by G. V. Parmelee and R. G. Huebscher (A.S.H.V.E. Reseabch Bulletin, No. 3, p. 40; also published in A.S.H.V.E. Tbansactions, Vol. 53, 1947, p. 276). ' 8 A.S.H.V.E. Research Report No. 1399--Heat Flow through Unshaded-Glass: Design Data for Load Calculations, by G. V. Parmelee and W. W. Aubele. (A.S.H.V.E. Tbansactions, Vol. 56,1950, p. 371). . ' ' Radiation and Convection Across Air Spaces in Frame Construction, by G. B. Wilkes and C. M. F. Peterson (A.S.H.V.E. Tbansactions, Vol. 43,1937, p. 351). ' 10 Thermal Test Coefficients of Aluminum Insulation for Buildings, by G. B. Wilkes, F. G. Hechter and E. R. Queer (A.S.H.V.E. Tbansactions, Vol. 46;.1940, p. 109). 11 Effect of Studs and Joists on Heat Flow Through Frame Walls and Ceilings, by Paul D. Close (Heating, Piping and Air Conditioning, October, 1943, p. 529). 18 A.S.H.V.E. Reseabch Repost No. 1213--Heat Loss Through Basement Walls and Floors, by F. C. Houghten, S. I. Taimuty, Carl Gutberlet and C. J. Brown (A.S.H.V.E. Tbansactions, Vol. 48, 1942, p. 369). , 18 Measurements of Heat Losses from Slab Floors, by R. S. Dill, Wm. C. Robinson andH, E. Robinson {National Bureau of Standards, Building Materials and Structures Report BMS 103). 18 See pp. 130-132 of Reference 7. 18 Heat Transmission through Glass, by G. V. Parmelee (A.S.H.V.E. Reseabch Bulletin No. 1, July 1947). . BIBLIOGRAPHY A.S.H.V.E. Research Reports: . No. 852--Effects of Air Velocities on Surface Coefficients, by F. B. Rowley,' A. B. Algren and J. L. i Blackshaw (A.S.H.V.E. Transactions, Vol. 36,1930, p..123). No. 895--Wind Velocity Gradients Near a Surface and Their Effect on Film Conductance, by F: C. Houghten and Paul McDermott (A.S.H.V.E. Transactions, Vol. 37,1931, p. 301). No. 914--Surface Coefficients as Affected by Direction of Wind, by F. B. Rowley and W. A. Eckley (A.S.H.V.E. Transactions, Vol. 38, 1932, p. 33). . No. 915--Conductivity of Concrete, by F. C. Houghten and Carl Gutberlet (A.S.H.V.E. Transac tions, Vol. 38, 1932, p. 47). No. 964--The Heat Conductivity of Wood at Climatic Temperature Differences, by F. B. Rowley (A.S.H.V.E. Transactions, Vol. 39, 1933, p. 329). No. 996--Insulating Value of Bright Metallic Surfaces, by F. B. Rowley (A.S.H.V.E. Transactions, Vol. 40, 1934, p. 413). No. 1026--Thermal Properties of Concrete Construction, by F. B. Rowley, A. B. Algren aDd Clifford Carlson (A.S.H.V.E. Transactions, Vol: 42, 1936, p. 33). No. 1048--Thermal Properties of Concrete Construction, by F, B. Rowley, A. B. Algren and Robert Lander (A.S.H.V.E. Transactions, Vol. 43, 1937, p. 33). No. 1351--Overall Coefficients for Flat Glass Determined under Natural Weather Conditions, by G. V. Parmelee and W. W. Aubele (A.S.H.V.E. Transactions, Vol.-55, 1949; p. 39)-. Insulating Effect of Successive Air Space Bounded by Bright Metallic Surfaces,'by L. W. Schad (A.S.H.V.E. Transactions, Vol. 37, 1931, p. 285). . ^Thermal Conductivity of Wood, by J. D. M&cLean (A.S.H.V.E. Transactions, Vofc:47, 1941, p; 323). The Specific Heat of Thermal Insulating Materials, by G. B. Wilkes and C. O. Wood (A;S:H;V.E. Trans actions, Vol. 48, 1942, p. 493). Heat Loss Studies in Four Identical Buildings to Determine the Effect of Insulation, by D. B- Anderson (A.S.H.V.E. Transactions, Vol. 48, 1942, p. 471). . Effect of Ceiling Insulation upon Summer Comfort, by T. D. Phillips {National Bureau of Standards, RepTohret rBmMaSl 5In2s, uJlualtyion1,M1a94d0e).of Wood-Base Materia. ls, Its Application and Use in Houses, by L. V. Tecsdale. (U. S. Forest products Laboratory Report No. B.1740, October \91Q). '' ' Heat Transmission Through Building Materials, by F. B. Rowley and A. B. Algren (University ofMinns1 tola. Engineering Experiment Station Bulletin No. 8). BuUding.Insulation, by P. D. Close (American Technical Society, Chicago, 1945). , r 3f, CHAPTER 10 WATER VAPOR AND CONDENSATION IN BUILDING CONSTRUCTION Basic Principles, Visible Condensation, Vapor Transmission Through Materials, Permeance Data and Testing, Concealed Condensation in Heated, Buildings, Control of Concealed Condensation, Condensation in Cooled Structures WATER as a vapor is present in all air and as adsorbed moisture in building materials such as wood. Even dense materials like glass hold considerable adsorbed moisture on their surfaces. In each of these places water may be harmless or even, desirable, if its quantity is not ex cessive. Excessive moisture in building materials may cause mold, rot, and rust. Water, blistering may. damage seriously the exterior, paint on wood siding when the sidmg moisture content rises above a safe level. While excessive moisture in building materials may be caused by rain leak age, it frequently is due-to.water vapor migration, a phenomenon likely to be associated with a temperature difference. Thus it may occur in the walls and roofs of heated' buildings in winter, and in the enclosure of re frigerated spaces at all seasons. Water vapor released within a building, either incidentally or intentionally, may result in excessive moisture in the structure. . The behavior of water vapor is too often overlooked or given scant con-, sideration in the design and construction of buildings and in the layout of air conditioning processes. It is an important factor to consider in the construction of residences arid public buildings in cold climates and to a lesser extent in warm climates. It is extremely important to consider the moisture problem in the construction of cold storage and low temperature rooms. Manufacturing processes which demand a high humidity, require buildings designed to reduce the effect of moisture on the structure. Moisture problems in residences occur in winter and becoine increasingly important as homes are built smaller and tighter. Water vapor originates from such necessary living requirements as cooking, laundering, bathing and the breathing and perspiration of people. In a typical family of four, the average daily production of water vapor from these sources may be as much as 25 lb, and may be much greater where such appliances as humidi fiers, automatic washers and dryers are used.1 Another large source of water vapor is sometimes the bare earth in a crawl space or basement. All this water vapor must escape from the dwelling. BASIC PRINCIPLES Water vapor in air is a gas which occupies all the space and has the same properties that it would have if the (dry) air were not present. It is steam at a low temperature and pressure. Generally it is superheated, j-e., not saturated. When water vapor is saturated, the space (or air) holds all the water vapor that it can at the existing temperature, and its vapor pressure is a maximum. A smaller content of water vapor produces less vapor pressure. The ratio of this pressure to the saturation pressure at the given temperature is called the relative humidity of the space. If an air-vapor mixture at a given relative humidity is cooled, its vapor Pressure is unchanged but its relative humidity increases until at some 201 . 202 CHAPTER 10 1954 Guide'% .. . . ii temperature it reaches 100 percent. That temperature is its dew-pomt. t; Evidently the vapor pressure which holds constant throughout this process / is the saturation vapor pressure for the dew-point temperature. Cooling ~ below the dew-point results in condensation of some of the vapor into liquid water (or frost at low temperatures) with a reduction of vapor pres sure. As an example, air at 70 F and 40 percent relative humidity has a ' vapor pressure of 0.40 X 0.73916 = 0.29566 in. Hg, and may be cooled 1 to 44.6 F with no change of vapor pressure. At 44.6 F the vapor becomes - saturated, the relative humidity being 100 percent, and this temperature is the dew-point temperature at the start and also at any stage of the cool- - ing. If the air contacts a surface colder than 44.6 F, condensation will occur on that surface. In fact, this removal of water vapor tends to re- . duce the dew-point of near-by air to the temperature of the cold surface: At a distance from the cold surface the dew-point temperature and the , vapor pressure may be higher, when such a point is in the path of vapor movement from a vapor source to the point of condensation. Such move ment of vapor may occur by diffusion without motion of the air, or by , transportation if the air moves, the latter mechanism being generally more important in larger air spaces. VISIBLE CONDENSATION , Just as moisture collects on the outer surface of a glass of cold water, so . does it also condense on other cold materials. In winter, visible con densation 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 unseen, any condensation on a visible surface will for convenience here be called visible condensation to distinguish it from concealed condensation. Within residences and public buildings, visible condensation occurs in winter and may damage decorative finishes and window sash. Interior visible condensation occurs when any surface is colder than the dewpoint of the near-by air. The temperature of any such surface-- wall, roof, or glass--is dependent upon the air temperature inside and out-: side 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. 1 shows; the relative humidity in a room at 70 F when visible condensation will, appear at various (7-values. The curves for single and double glass at, their usual (7-values are included. It should be noted that [/-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 general, be lower, at the bottom due to such things as stratification of inside air and the ef--: fects of air leakage and of convection in walls with air spaces. Since con densation seeks the coldest spot, values from Fig. 1 can be applied only " with caution. As a result, the limit of relative humidity for a non-homo- ^ geneous wall is lower than might be inferred from its average (/-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 warmer than the dew-point tempera-/' ture, is exposed to moisture damage--such as swelling, mould or discolors-1. tion. ;.t. Visible condensation may occur also in summer. It is often seen on/ basement concrete walls and floors which are cooled by the earth and whichp; Water Vapor and Condensation in Building Construction 203 being massive, tend to hold a constant temperature from day to day while the weather dew-point temperature rises. When no water vapor is re leased in the space, the dew-point tends to equal that of the outside (though it is likely to lag when there is slight ventilation). At times the dew point temperature rises above the temperature of walls and floors and condensation results. If the basement is decorated the. trouble may be serious. As an operating problem, the solution may be to reduce ventila tion 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 accom plished 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 a desiccant to retard the dew-point rise during the day. In base ment walls and floors insulation should be applied in the concrete or on its outside. Insulation placed on the inside of such walls eliminates visible Fig. 1. Relative Humidity at Which Visible Condensation Will Appeab on Inside Surface condensation but fosters 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-surface dwellings should be designed for occupancy and 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 heating system. In a northern climate where high dew-point temperatures occur in summer, con densation or very high relative humidity may damage rugs which are them selves contributors to the trouble since they reduce the floor slab tempera ture. 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 warm,ng is accomplished by the removal of rugs and abundant ventilation at proper times. In their design, floor 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 insulating value that is unaffected by water on its lower side would be desirable in the less favorable northern climates. The avoidance of interior visible condensation is partly a construction 204 ' CHAPTER 10 1954 Guide ''V}s and partly an operating problem. It is accomplished by reducing the in terior 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 giving attention to the sources of the moisture, and m winter, ;> may be controlled by ventilation, or possibly by some moisture absorption ; process. The temperatures of the inside room surfaces in winter may be : increased by adding insulation to outside walls, by double glazing of win dows, by circulating warm air over the surface, or perhaps by direct heating of the surface. The most expedient method of overcoming a surface con- densation difficulty will depend upon special conditions surrounding the ' problem. ''( VAPOR TRANSMISSION THROUGH MATERIALS " The condensation of moisture within buildings is not limited to viable J surfaces. Vapor permeates through certain materials very readily and : may penetrate exterior or cold walls and contact material therein having a i temperature below the dew point of the vapor. At these places the vapor will condense to form liquid water or frost. Such concealed condensation may, if excessive, cause serious damage which is particularly insidious when it continues without detection. An accumulation of hidden condensation ^ often causes great difficulty in long-range processes. The principal mechanism by which water vapor passes through solid * materials is a process of diffusion, the net transfer requiring a difference ; of vapor pressure. Various writers have suggested the possibility that i- adsorbed moisture (which is neither vapor nor liquid) moves from a region of high concentration to one of lower concentration without the benefit of*; a vapor pressure difference, but this action has not been conclusively/; demonstrated and probably is negligible in the problems here considered.); The property of a material which enables it to transmit vapor is known ash its vapor permeability. Other forces which play an important part are);, capillarity and gravity (when the vapor changes to liquid at any point in?' its path), and the hygroscopic adsorption of moisture (which, for many)) materials, is nearly proportional to relative humidity). 'M The term permeability has frequently been applied to the rate of vapor-i transmission for the thickness of the material considered or tested, but1-this use is not consistent with the use of conductivity (thermal) which relates) to a property of the material based on unit thickness. It has been sug-J-l gested2 that the term permeance (similar to conductance in heat transfer)s'f| be used when referring to any specimen of definite thickness, of an a&M sembly of such pieces. This recommendation is followed in this chapter.)? The term permeability, as used herein, defines a property of the materiid . and is numerically equal to the permeance of a unit thickness. (I'; The theory covering water vapor transmission through materials leads*; to the following formula, ' `0 W = MAT Ap .- - where, . - .' . W = total weight of vapor transmitted through the specimen, grains. (1)>. lbs tg' ' A = area of the specimen, square feet. T = time during which the transmission occurred, hours. .. il'f-', Ap = the difference of the vapor pressure across the specimen, inches of mercury/; M = the permeance of the specimen, in perms, or grains per (square foot) (hoiiyj' (inch of mercury vapor pressure difference). . Water Vapor and Condensation in.Building Construction 205 The basic units in Equation 1 are favored by the building industry. The designation perm for the unit of permeance has been proposed2 as a convenient substitute for the unit, 1 grain per (square foot) (hour) (inch of mercury vapor pressure difference), and this recommendation is followed herein, The weight of vapor transmitted is unquestionably proportional to area and time, but is not always proportional to the vapor pressure difference. Proportionality is a useful relation when applied with caution in a limited range, but the expression per inch of mercury does not sanction an un restricted extension of this relation. In other words, the permeance of a specimen is not a constant under every condition. This fact must be con sidered but is generally not an obstacle in the solution , of many practical problems: . Vapor resistance is the reciprocal of permeance, and theory indicates that the vapor resistance of a homogeneous specimen is proportional to its thickness. Permeance, therefore, is inversely proportional to thickness, and: M s 7 where, - -- or, m = Mt (2) _ M = the permeance of the specimen, perms. t = the thickness of the specimen, inches. As defined by Equation 2, jx is the permeability of the material or the permeance per unit thickness. Using consistent units, permeability is expressed in perm-inches, a perm-inch being equal to one grain per (square foot) (hour) (inch of mercury per inch of thickness.) Equations 1 and 2 may be combined to give: W = PATH 'S) where, M = the average permeability of the material. (The spot permeability in thin ele ments may be progressively different throughout the thickness.) The overall vapor resistance of an assembly (like a wall) of materials in series is the sum of the resistances of its component parts provided con densation does not take place within the assembly. Expressed in the more usual terms, the permeances (Mi, Mj, M3, etc.) of the individual pieces may be combined by use of the formula M= 1 1 + _L.+ 1 + ... Mi Mt M, Mn (4) Equation 4 holds for materials that are reasonably homogeneous and in a condition of steady state where the transmission at all points is a vapor diffusion process as, for example, in a vapor transmission test. Actually, be conditions of moisture movement through a building wall are generally uinerent. A steady state, where the entering and leaving moisture are n^th rare!y exists, and frequently, the moisture in some portion of the path is liquid, in which case forces of capillarity and gravity are usually 206 CHAPTER 10 1954 Guide Vf more important. It is therefore evident that the formula can be used only for certain portions of a building structure. Another caution is that the ^ permeances of the several pieces must apply at the existing conditions. The permeability of a material has been defined as one of its properties but it is not a fixed property for all conditions of exposure. Some materials ' like wood, because of their structure and hygroscopicity, are much more J permeable to water vapor when the relative humidity is high. Since the h equilibrium moisture content of permeable materials is increased to a! 1 greater or less degree by exposure to high relative humidity, it is likely i that this sorbed moisture contributes to the mechanism of transfer. *! The variations in the permeability of sugar pine wood are shown in Fig. 2 3 It is notable that high relative humidity on either side of a speci-. men increases its permeance and the average permeability of the piece.' i The spot permeability is shown, but the average is more readily used in PERCENT RELATIVE HUMIDITY ON THE H1CH PRESSURE SIDE' Fig. 2. Permeability of Wood (Sugar Pine) '; practical calculation. Temperature also affects permeability, but for mostg materials is considered a minor factor, although data are few. Thesej't variations are to be expected in most materials and therefore, due care is|j required in choosing for each the proper value at its exposure conditional Exact calculation by any of the preceding formulas, therefore, requires aj|' knowledge of such variations as shown in Fig. 2 for each material, butip. approximate calculations are readily made and are adequate for mosty. requirements. PERMEANCE DATA AND TESTING 3^ The simplest method of finding the vapor permeance of a specimen is tog seal it over the top of a cup containing desiccant or water, placing it inAS controlled atmosphere, and weighing it periodically. The steady rate ofg weight gain or loss is normally the water vapor transfer. When the cupj^ contains a desiccant the procedure is called the dry-cup method and when|-: Water Vapor and Condensation in Building Construction 207 the cup contains water, the wet-cup method. Usually the outside at mosphere is held at 50 percent relative humidity, thus providing in either method substantially the same difference of vapor pressure, but the results obtained by the two methods on the same specimen are likely to be much different, the wet method producing the higher values. It is obvious that any statement of permeance of a specimen should include the conditions of test. The permeance of a piece of material in a given service is best known if tested under conditions duplicating the serv ice. Its permeance may be adequately judged, however, if it is tested by both dry and wet methods thus providing relative humidity conditions that usually include those to be encountered in service. Unfortunately, the conditions of testing have not been standardized, and test data have frequently been presented in terms of weight transmitted Table 1. Conversion. Factors for Vapor Transfer Units Multiply Ncmbeb op to Obtain grama (24 hrs) (sq m) grains (hr) (sq ft) grama (24 hre) (sq m) grains (br) (sq ft) Perms by same method* by same method* by same method* method A & B. 73.4 F method C & D. 90 F . method E, 100 F 1 0.0597 0.144 0.0840 0.0344 - 16.7 1 0.575 % Relative Humidity on the Two Sides op Specimen : Method Temperature-F Id cup A 73.4 0 B 73.4 100 C 90 0 D 90 100 100 0 Data obtained by one method cannot be reliably converted to another method. Outside cup 50 50 50 90 per (unit area) (unit time). Such data may be called water vapor trans mission 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 units (weight, area and time) is also required. The following formula applies: where, . _ WVT rating Permeance = ------------------ Ap (5) ' rating = weight of vapor transmitted, grains per (sq ft) (hour). . Ap = vapor pressure difference in the test, in inches of mercury. Permeance is expressed in perms. Table 1 presents the conversion factors applicable to the commonly ed units and test methods. Table 2 Dresents some data on typical CHAPTER 10 Table 2. Permeance and Permeability of Materials i able a. x TO Wateb Vapor ........................ Material ;. " ` ' . 1 i Per J meance Perm - ; ....----------- ----------:------------- . ; - Air (still) Insulation . .. Cellular glass Corkboard ; Structurs?lB3aiatinKBoard (vegetable, uncoated) Pbrmsabiuty* Peru-inch ! 70 i RHi-RHs. is a-- Rev.I 120. 0.0 2.1-2.6 9.5. 20-60, 116. 92-73 75-0 100-45 40-x 100-30 >; 3 d d w ' t w 6 9 7 / 4- ^Sugar Pius (see Fig. 2) ,,. . Pl^rood (IUtenor type3ply D.F.). 54m^ 0.72 1.86 0.4-5.4 various, tv 50 *4 . so- . 4 3 11 ll Masonry ., ConcreS (Scored block wall, limestone agrgt.) Brick wall--with mortal--4 m* Tile wall--with mortar--4 in. . 2.4 0.8 , 0.12 : Interior Finish Piaster on wood lath Plaster on metal lath--H ,* Plaster on plain gypeum lath (with studs) Gypsum wall board--plain--Jkm- Tniuln*'T'g wall board (uncoated) H m* 11. 15. 20. . 50. 50-90 Paint--2 coats Asphaltic paint on plywood Aluminum in varnish on wood Enamels, brushed on smooth . Primer* or Sealer* on insulating wall board + 1 coat tat Flat paint (alone) on insulati mSriwd'iotl' prepared paint on wood elding White lead-sine oxide A linseed oil on wood 0.4 0.3-0.5 0.5-1.5 0.9-2.1 1.6-3. 4. 30.-85. I ; 0.3-1.0 0.9 3.2 100-45 79-68 50-x 50-x 100-30 40-x 40-85 50-20 40-x 100-30 95-0 92-0 40-x 40-x 40-x 40-x 50-0 95-0 w t t t w t t V t Wd b t ,t t t d d 9 3 8 8 4 7 3 13 7 4 10 3 7 7 7 7 13 u Buzlmnq PAreas and Felts Duplex sheet, asphalt laminae, aluminum foil one Sastiduerated and coated felt heavy roll roofing Kraft and otpfialt 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-pound tar felt Single sheet Kraft, double infused t MDeetshcordipst:iodn--isdarygcuuidpe; own--lyw, eatndcudpo;est--ntowt oinsteumrepeperarmtuereasn;ceb.--special cell; v--air velocity bot.h, sid, e*.;.;.,,' 4--average of four methods. '"* t References. No. 7 also includes Bulletin* 22 and 25 at the Engineering Experiment Station, Dnmrriifl.---' of iiinneeota. No. 13 includes data to be published by the Engineering Experiment Station, Th* Penn*ylvani?%Z State College. ;<*>< building materials showing, in each case, the source and method and, where apWpliactaebrl-ep,rothoefedthibcuknildeisnsgtepsatpeedr.s are listed in Federal Specifications UTJ-P'i; 147, May 24,1948, according to water vapor resistance required as: ' Class A. For uses where a high degree of water vapor resistance is required. J? Class B. For uses where a lower degree of water vapor resistance ana of water - resistance is required. ' J't-j Class C. For uses where a moderate degree of water resistance is required. Class D. For uses where low resistance te water vapor is required. . Water Vapor and Condensation in Building Construction 209. It may be noted that a paper may be walerrproof, i.e. possess water re sistance, and still havelow water vapor resistance. Detail requirements in. these specifications are given as follows, the specified WVT Test, being a dry method at 73 F: Class A 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 shall have a minimum water resistance of 24 hr, and a maxi mum water vapor permeability (WVT) of 4 grams per sqiiare meter per 24 hr, (i.e.1 0.576 perm). :^ Class 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 ahalf have a minimum water resistance of 16 hr, and a maxi mum water vapor permeability (WVT) of 6 grams per square meter per 24 hr, (i.e. 0.864 perm). : . 1. Class 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 of both strengths shall have a minimum water resistance of 8 hr. Class D paper shall have a minimum tensile strength in each direction of 20 lb per inch width. The paper shall have a minimum water resistance of 10 min., a mini mum water vapor permeability (WVT) of 35 grams per square meter per 24 hr, (i.e. 5.04 perms). CONCEALED CONDENSATION IN HEATED BUILDINGS Water vapor produced in a building necessarily raises the vapor pressure above that outside 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 tor 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 humidifi cation 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 figure applying to a very small, crowded and unventilated dwelling. A 40 percent level is considered representative of a substantial number of modem tightly constmcted small houses, although the average house relative humidity is probably below 25 percent. Surveys in residences show that the relative humidity increases as would be expected in warmer weather. Fig. 3 represents the results of one such survey.4 When water vapor is allowed to enter a wall and condensation 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 surface is non-absorbing or is already saturated with water. In weather that is con tinuously cold for a long period, the frost may build back into a cavity or nbrous. insulation and, when it reaches a warmer plane, will run to lower, cooler levels where it forms a mass of ice. Water seepage to the weather Sfde may occur harmlessly in masonry walls when the weather is above feezing but water seepage into the building must obviously be avoided; ? typical frame construction with wood sheathing which has large water absorbing capacity, seepage is rare and occurs only after a long period of sh a<L- C^ weather. More generally, moisture accumulates in wood eathmg and siding through the colder months and reaches a peak in late nter, after which the drying of spring and summer completes the annual 210 CHAPTER' 10 '1954 Guide cycle. The average winter temperature and its duration are factors in the condensation problem. In Fig. 4 the map of the United States is divided in to condensation zones based on winter weather conditions. The solid lines separating the zones follow state lines, and are those recommended by the Housing and Home Finance Agency for the guidance of owners, builders, and architects.5 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 reasonably good correlation between the zones deter mined by the two sets of lines. Zone I roughly includes those areas where the design temperature is -- 20 F or colder; zone II those for which the design temperature is zero to --20 F, and zone III those at zero and wanner. Within each zone, similar degrees 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 -*! Water Vapor and Condensation in Building Construction 211 CONTROL OF CONCEALED CONDENSATION An excessive accumulation of moisture in . walls (or roofs) can be pre vented by one or more of the following measures: (l) provide a vapor bar rier to limit vapor entrance into the wall' (2) ventilate the building to reduce vapor pressure therein, (3) ventilate 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 ventilation of the living space, either inci dental or planned, is necessary. Also, a small amount of cavity ventilation is essential in cases where the .vapor inflow is not completely stopped and the moisture storing capacity of the outer wall elements is slight. This applies to sojne prefabricated designs using metal sjding. Fig. 3. Relative Humidity in Dwellings coverings such as paint; and while paint is likely to be ruptured by exees- v sive moisture, no such relief occurs in roofs. Thus roofs furnish con-jijt; spicuous 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 --l and other members that are below the floor line and near to the outside. % Water vapor from the crawl 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 temperatur of the outer elements of the structure, thus increasing the possibility o condensation if the vapor path to the cold surface is not blocked. Sine low vapor resistance is a characteristic of fibrous insulation, the neede vapor resistance must be provided by other means. It is to be noted tha in typical residential conditions, condensation does not occur in fibrou insulation itself, except when frost has formed on sheathing and gradually built backward among the fibers. Wet insulation may result from this , condition or from liquid condensation seeping down from a higher level. Fig. 4. Condensation Zones in the United States (Zones Include Areas with Design Temperatures about as follows: Zone I. --20 F and lower; Zone II, 0 F to -- 20 F; and Zone III, above 0 F.-Note that cross hatched areas are outside of Zones I and III.) . Vapor barrier sheets are often built into the wall near the 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 side of plaster base materials. Special designs may be attached like wall paper to the inside of the wall, when satisfactory from the decorative view point. Sheet barriers often contain asphalt as the vapor resisting ingredient; metal foils, so placed that they are not too cold, may also be used. The interior wall board or finish material may itself be vapor resistant, or a barrier coating may be applied to its concealed side when that side will not be too cold. The interior finished surface may be coated with a suit able 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 resistance, is not 212 CHAPTER 10 1954 Guide -f likely to be so effective as a sheet barrier properly applied during the wall construction. This applies especially to houses of more than one story _ haying 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, requiring normally the painting fifthe ceiling as well as the walls. Similar treatment may be required on internal partitions, or.at least the first stud space adjacent to the cold wall. The necessary banier resistance depends on a number of factors. When the vapor flow occurs in annual cycles as in heated buildings, the require- . ihent is not so 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 time of moisture accumulation in the cold outer elements and their safe moisture holding capacity is an I important factor in determining the barrier requirement. A house without' sheathing requires a better barrier; and 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. Tor typical frame dwellings with wood sheathing and siding in the north ern 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 barrier 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 implies that its permeance be definitely established. The usually accepted test procedure for-this pur pose 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 higher than minimum; permeance is not preferred. : : i 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 con struction includes any material that would be damaged by moisture or its i freezing. This applies to all condensation zones in Fig. 4 when the U valuer for the wall is lower than 0.25 Btu per (sq ft) (hr) (F deg), and it applies irC Zone I and Zone II to walls of higher transmittance. In applying vapor resistance to a wall, there are certain fundamental.; principles which should. be followed.. First, the vapor barrier should bfl- placed as near to the warm surface of the wall as practicable. Second, it; should be continuous with :no direct openings through the barrier. Good.; workmanship and application. are very, important. Workmanship that. leaves two openings through the barrier, or around its margin, at different1 levels, connecting air spaces at only slightly different temperatures, leaves a path for thermosyphon air rotation which will transport large amounts of;'- water vapor from the warmer space to the colder. If a membrane barrier: is used back of the plaster or interior finish, its joints should be made overs some solid framing member, and not between the studs or in similar places;; Usually a two-inch lap over a framing member will make a sufficiently^ tight joint when the interior finish is applied. Such a lap, however, without; backing would not be adequate. Barriers attached to the warm side QC insulation should form a continuous unbroken membrane over the entire" insulated area. Edges should be lapped over framing members; ends of * Water Vapor and Condensation in Building Construction 213; strips should be fastened,by lapping over plates or headers. All 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 Living Space. The second measure listed for the control ,of concealed condensation is ventilation of the house. This measure isobviously necessary as an accompaniment to a vapor barrier since, if thebarrier 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. 5, which also shows the small amount of water vapor escaping into the barrier-equipped, well-in sulated walls and ceilings (2000 sq ft) of a typical small dwelling, the floor being neglected. Evidently, ventilation of 2000 cu ft per hr will remove 21 lbs of vapor per day with the relative humidity at 40 percent, while at the same time 1.5 lbs 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. 1. By reference to Chapter 6, Fig. 5. Water Vapor Balance in a Dwelling (Vapor Barrier, 1 perm; Wall and Ceiling Area 2000 sq ft Inaulated) 2000 cu ft per hr appears to be near the minimum for 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 neces sary in kitchen and laundry for proper vapor control and for the reduc tion of peaks in relative humidity which would otherwise occur in those areas. ' 3. Ventilation of Structure. The third measure listed for the control of concealed condensation, ventilation of the structure itself, is effective in certain cases especially as a supplement to warm side vapor resistance . which is considerable but not of itself fully adequate. Air from outside is nseAdt.tic_s_Thaend*vecrnatsw. -lm___s_up__sa_ct_e_b_s_e_m_shaiyelbdeedcofrnosmideturheioed eLnuvtruatnmc/ec as parts voif of rfoauinl 2aUnIUd insects. the structure, and r these portions ventilation is practically a necessity. Attic ventilation .ss long been an established practice but .its effectiveness is likely to be uumnjshed by the newer practice of adding insulation to ceilings. In- lation requires added ventilation which in turn necessitates adequate. N ation. The recommended ventilation shown in Table 3 for dwellings5 214 CHAPTER 10 i . IS* 1954 Guide . f is based on such insulation. The net'area refers to the total of all openings f 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. 4 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, transporting 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 openings, one at each , Table 3. Recommended Good Pbactices-Loft and'Attic Ventilation* -I F 3 12uat Roof--Slope Less thaw Inches in Inches Condensation Zone Ic: Total net area of ventilation should be foothb 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 III: Same as for Zone I.. ,. - Gable Roob--Slope oveb 3 Inches in 12 Inches Condensation Zone I: Total net area of at least 2 louvers on oppositesideslocated near ihe 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. < r-. Condensation Zone HI: Same as for Zone II.----------------------------------------------- '/ . - 'a=ag= -- . ' --------.< c Hip Roop Condensation Zone I'-Total net area of ventilation should be ($oothb.with (6othb distributed uniformly at the eaves and (tooth" located at the ridge with all spaces interconnected. A vapor barrier should also be -y, used in the top story ceiling. . '_ _ v Condensation Zone II: Same ventilation as for Zone!. A vapor barrier is not considered necessary. Condensation Zone III: Same as for Zone II. `p Gable on Hip Roop--With Occupawct Contemplated Condensation Zone I:. Total net area of ventilation shoud be Hoothb with J6ootbb distributed uniformly at the eaves and Hoothb located at the ridge with all spaces interconnected. A vapor barrier should also be used "? on the warm side of the top full story ceiling, the dwarf walls, the sloping part of the roof, and the attic jj story ceiling. -' ( Condensation Zone II: Same aa for Zone I. _' J Condensation Zone III: Same as for Zone 1 except that a vapor barrier is not considered necessary if insula*. * tion is omitted. . .. * It is reoogniied that in many areas increased ventilation may be desirable for summer comfort, FoH - winter comfort, insulation is recommended between a living space and aloft or attic ventilated at these rates.;' - . .. . .... ,-----i___i ' V s Refers to area enclosed within building lines at cave level. cThe sone numbers refer to Fig- 4- 's corner, as high as possible, should be provided.6 Their total net area be calculated by the formula: 21, A a = -- 4- -- 100 300 'H (60 where: L, = the perimeter of the crawl space, linear ft. A = the area of the crawl space, square feet. . a iso = the total net area of all vents, (or the grosB area if 4-mesh screen used) square feet. M This ventilation is usually sufficient but cools the first floor so much .... insulation is needed. A better treatment is a cover on the damp ground^ ' > U %? Water Vapor and Condensation in Building Construction 215 This cover may be a concrete slab, or merely heavy roll roofing laid on a graded surface with its edges lapped 2 in. (but not necessarily cemented). With this barrier, the vent area may be reduced to 10. percent of that calculated by Equation 6. > In building walls, cavity ventilation can be applied in a moderate climate as the sole vapor control system. In general, however, air passages in walls designed to remove an unrestricted vapor supply are unduly large and may waste considerable heat. On the other hand, a barrier as the only control measure would, in some cases, require so high a resistance as to be impractical. Ventilation of the structure in conjunction with a vapor barrier, is a procedure with important applications, but its general utility has not been fully investigated. Ventilation is most effective when each structural space has a clearly defined air passage with an inlet and outlet. In walls a small thermosyphon effect may be utilized by locating one vent at the bottom and one at the top of each space. The best time to vapor-proof a building is during its construction. After a building is completed, ventilation of the occupied space is the most easily applied of the three basic control measures. Paint that is chosen for its low vapor permeance can be applied as a barrier on the interior with good results, care being taken that all areas, including parts of partitions and ceilings which offer an indirect vapor path to the cold wall, are covered. Ventilation of the wall cavity is effective in certain cases especially to sup plement the foregoing measures. When such venting is required, each cavity space isolated by framing should be separately vented with an inlet and outlet judiciously placed, to accomplish proper air change. CONDENSATION IN COOLED STRUCTURES Water vapor is sometimes an even greater problem in cooled structures than in those which are heat^l, but the basic facts of its migration and condensation on cold surfaces are the same. Refrigerators, cold pipes and cold vessels all require insulation 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 than that required in residential construction. In the case of an insulated cold pipe line, the process is likely to be uninterrupted 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 appli cation vapor control requires insulating material that is itself very highly resistant to water vapor or a coating whose permeance is the minimum obtainable, not over 0.1 perm. Metal coverings are desirable but difficult to apply. Similar considerations apply in the case of cold rooms whether con structed inside a heated building or as a separate building. In the latter case, cold rooms operating above freezing provide some periods of vapor reversal in winter but such drying can be of little help. Refrigerators, r v.eVer' ^ lined with cement or other vapor permeant material, will allow shght amounts of vapor to pass and to that extent reduce the accumulation f moisture that may have penetrated the barrier. While this is helpful, emphasis must be placed on an adequate warm side barrier not greater than 0.1 perm. Summer air cooling for comfort does not involve serious vapor problems 216 CHAPTER 10 1954 Guide and vapor control measures are not essential. Normally the( cooled air is V little, if any, colder than the dew-point temperature of the outside at- 1 mosphere and there are no areas of condensation. However, the interior ' vapor pressure is often below that outside and therefore, vapor, which diffuses inward, adds to the cooling load. - Vapor barriers in walls installed for .winter needs, are a help in reducing this element of the cooling load; REFERENCES , 1 Research in Home Humidity Control, by S. C. Hite and J. L. Dray (Purdue University, Engineering 'Experiment Station, Research.series No.108, November 1948). ` . ? Permeance Measurement Improved by Special Cell, by F. A. Joy and E. R Queer (A.S.H.Y.E. Trans actions, Vol. 65, 1949, p.. 377). :' :. . ; . '' * Water Vapor Transfer Through Building Material*, by F. X. Joy, E. R. Queer and R. E. Schreiner (Penn- 'Sylvania. State College, EngineeringEsperiment Station Bulletin No. 61, December 1948). * Remedial Measures for Building,Construction, by L. V. Teesdale (Report R1710 of U. S. Forest Products Laboratory 1947). . * Condensation Control in Dwelling Constructions ( U. S. Housing and Home Finance Agency, 1949). `' * The Diffusion of Water Vapor Through Various Building Materials, by J. D. 'Babbitt (Canadian Jour nal of Research, Vol.l7,` February, T939, p. 15).' ' " ' . - ' - 7 Methods of Moisture Control and Their Application to Building Construction, by F. B.`Rowley, A. B. Algren and C, E. Lund ( University of Minnesota, Engineering Experiment Station:BxdUtin No. 17)., . 8 The Relation of Wall Construction to Moisture Accumulation in FBI-Type Insulation by.Henry J. Barre (lowaState College ofAgriculture and Mechanic Arts Agricultural Experiment Station Bulletin No. 271, 1940.) Moisture Migration: A Survey of-Theory and Existing.Knowledge, by P. F. McDermott (Refrigerat ing Engineering, August 1ll9H41i,, p. 1iv0w3)j. . , , .. .. . . . ... tt ., Permeability of Paint Films to Moisture by R. I. Wray and A. R. Van Voret (Industrial and Engineer ing. Chemistry VaL 25, p. 842,1933): ; :. 11 Water Vapor. Transmission of Building Materials Using Four Different Testing Methods, by R. R. Britton and R. C. Reichel, (U, S. Housing and Home Finance Agency Technical Bulletin No. 12, January I960). . . - ; i* Water-Vapor Permeability of Building Papers and Other Sheet Materials, by E. R. Bell,' M. G. Seidl, and N. T. Krueger. (A.S.H.V:E. Transactions, Vol.. 57, 1953, p. 287). . : . u Value from unpublished tests of Pennsylvania State College Engineering Experiment Station. BIBLIOGRAPHY .i - : -Moisture Condensation in Building Walls, by H; W. Wooley (National Bureau of iSfandante.Report BMS63, K December. 14, 1940). -. . , .:>;! , , ; Condensation of Moisture and Its Relation to Building Construction and Operation, by, F. B. Rowley, 'T :AVB, Algren and C. E.'Lund (A.SiH.VJSJTBANaACTiONS, VoL 45, 1939, p. 231); .' . . A Theory Covering the Transfer of Vapor Through Materials, by F. B. Rowley (A.S.H.V.E. Transao - TIOns, Vol. 45. 1939,. p. 545). . . , . :. . . . j- Simultaneous Heat and Vapor Transfer Characteristics of an Insulating Material, by F. G. Hechler, E. R. 7 McLaughlin and E.R.Queei^(A.S.H.V.E. Transactions, Vol. 48, 1942, p.505). - ' : 7 .Comparative Resistance to ,Vapor Transmission of .Various Building Materials, by L. V. Tees* - dale (A.S.H.V.E. Transactions, Vol. 49, 1943, p. 124). Permissible Relative'Humidities in Humidified Buildings, by Paul D, Close (A.S.H.V.E: Journal/*' Section, Hailing, Piping and,Air Conditioning, December, 1939, p. 76G). , .: Condensation Within Wails, by F. B. Rowley, A. B. Algrezhand C. E. Lund (A.S.H.V.E, Transactions, Vol. 44, 1938, p. 95); : . -i CHAPTER 11 INFILTRATION AND VENTILATION Causes of Infiltration, Infiltration Due to Wind Pressure, Infiltration Due to Temperature Difference, Sealing of Vertical Openings, Infiltration Meas urement; 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 interstices, around windows and doors, and through floors and walls. Its magnitude depends on the structural design, workmanship, and condition of.the building. The rate of infiltration cannot be controlled by the inhabitants of the building to any considerable extent. Natural ventilation is the controlled displace ment of air through openings; such as windows, doors and ventilators as well as through combustion heating devices. .. . ' ! CAUSES OF INFILTRATION The air leakage which takes place through various apertures in buildings must be estimated in heating-and cooling calculations and enough heating or cooling capacity provided to offset the heat lost or gained by the air leakage. The rate of air flow into and out of a building depends oh the magnitude of the pressure difference between the inside and outside of the structure and on the resistances presented to this pressure difference. The pressure difference exerted on the building walls by the air may be caused either by wind or by a difference in density of the air inside and outside the building. The effect of the wind depends on the interrelation of the speed and direction of the wind and the exposure of the building. The effect of the difference in the density of the air depends on the magnitude of the inside-outside temperature difference, the height of the rooms,..the shape of the openings, and their elevation in the room or building. The effect of the difference in density is often referred to as the chimney or stack effect. The pattern of air flow through any part of the structure de pends on both the pressure difference and the openings. In general; when the pressure difference is the result of wind pressure, air .will enter .the building through openings in the windward walls and leave through open ings in the leeward walls or through ventilating ducts in the roof. When the pressure difference is caused by the inside-outside temperature differ ence the flow will be along the path of least resistance from inlets at lower levels to outlets at higher levels in a heated building or in the opposite direction for an air-conditioned building. ,, ; <. . An exact estimate of the amount of infiltration under design conditions !s difficult to make. The complicating factors include (1) variations in building construction, particularly as to width of crack or size of openings through which air leakage takes place; (2) the variations .in Wmd velocity and direction; (3) the exposure of. the building-with respect to air leakage openings, and with respect to adjoining buildings; (4) the 217 218 CHAPTER 11 1954 Guide variations in outride temperatures which influence the chimney effect; (5) the relative area and resistance of openings on the windward and leeward sides, and on the lower floors and on the upper floors; and (6) the influence of a planned air supply and the related outlet vents. Tight construction is essential for preventing large heat loss due to infiltration. INFILTRATION DUE TO WIND PRESSURE The wind causes a pressure to be exerted on one or two sides of a building. As a result, air comes into the building on the windward ride through cracks or porous construction, and a similar quantity of air leaves on the leeward side through like openings. In general, the resistance to air movement is similar on the windward to that on the leeward ride. This causes a building up of pressure within the building, and a lesser air leakage than that ex perienced in single wall tests as determined in the laboratory. It is assumed . Table 1. Infiltration Through Walls* Expressed in cubic feel per square foot per hour - Type op Wall Wind Velocity, Miles per Hour 5 10 25 20 25 30 8)4 in- Brick Wallb.. J Plain...... ........ 2 / PIasteredc___ 0.02 4 0.04 8 12 19 23 0.07 0.11 0.16 0.24 ( Plain._______ 13 in. Brick Wallb_ < Plastered*___ (.Plastered1*___ 1 0.01 0.03 4 0.01 0.10 7 0.03 0.21 12 0.04 0.36 16 0.07 0.53 21 0.10 0.72 Frame Wall, with lath and plaster*.. 0.03 0.07 0.13 0.18 0-23 '0.28 . * The values given in this table are 20 percent less than test values to allow for building up of pressure in ' rooms, and are based on test data reported in the papers listed in chapter footnotes. . k Constructed of porous brick and lime mortar--workmanship poor. . 0 Two eoate prepared gypsum plaster on brick. ,. d Furring, lath, and two coats prepared gypsum plaster on brick. * Wall construction: Bevel siding painted or cedar shingles, sheathing, building paper, wood lath and three ' coats gypsum plaster. - that actual building leakages, owing to this building up of pressure, will |f be 80 percent of laboratory test values. While there are cases where this is not true, tests in actual buildings substantiate the factor for the gen eral case. Mechanical ventilating systems are frequently designed to i'f produce positive or negative pressures in an enclosure, which are greater or lower than prevalent wind pressures. In such designs, if the specified rate at which air is to be supplied to, or removed from, the enclosure by posi--S tive means, exceeds the infiltration rate, it is common practice to use the ,gr. greater value in determining the heating capacity to warm the outside air. |J Infiltration Through Walls ! if} Data on infiltration through brick and frame walls are given in Table l.*,3s The brick walls listed in this table are walls which show poor workman- p; ship, and which are constructed of porous brick and lime mortar. For|t good workmanship, the leakage through hard brick walls with cement;,jr; lime mortar does not exceed one-third the values given. These tests?] indicate that plastering reduces the leakage by about 96 percent; a heavy fj Infiltration and Ventilation 219 coat of cold water paint, 50 percent; and three coats of oil paint carefully applied, 28 percent. The infiltration through walls ranges from 6 to 25 percent of that through windows and doors in a 10-story office building, with imperfect sealing of plaster at the baseboards of the rooms. With perfect sealing the range is from 0.5 to 2.7 percent; or a practically negli- ' gible quantity, which indicates the importance of good workmanship in proper sealing at the baseboard. It will be noted from Table 1 that the infiltration through properly plastered walls can be neglected. The value of building paper, when applied between sheathing and shingles, is indicated by Fig. 1, which represents the effect on outside con struction only, without lath and plaster. The effectiveness of plaster properly applied is no justification for the use of low grade building paper, or of the poor construction of the wall containing it. Not only is it diffi- FlG ' W'LTRATI0N THB0DGH Ttphs of Shingle Construction cult to secure and maintain the full effectiveness of the plaster, but also it is highly desirable to have two points of high resistance to air flow with an air space between them. The infiltration indicated in Fig. 1 is that de termined in the laboratory, and should be multiplied by the factor 0.80 to give proper working values. '~ Window and Door Leakage There are two methods of estimating air leakage through window and door cracks, namely, (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 clear ance, 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. 220 CHAPTER 11 1954 Guide : Table 2. Infiltration Through Windows Expressed in Cubic Feet per Foot of Crack per Hour* IwindVelocitt, Miles per Hour Remarks 5 10 15 20 25 30 Around frame in masonry wall--not calked Around firame in masounrryy wall--calked . ,,.c.Around frame in wood frame construction1*. 3 1 8` ; 14 .2 3 20 4 27 5 35 6 2 6 11 17 23 30 Total for average window, non-weather-stripped,. Double-Hung Wood Sftah Windows (Un He-in. crack and %4-m. clearance.6 Includes wood frame leakage ....................................... .. . locked) . Ditto, weatherstripped- -............................. . 1. Total for poorly fitted window, non-weather- 7 4 21 39 59 80 104 13 24 36 49 63 stripped, Ma-in. crack and M2-in. clearance.6 Includes wood frame leakage.......................... Ditto, weatherstripped*1. --'........ ................ ?7 -6 69. 111 154 199 249 19 34 51 71 92 Double-Hung Metal Non-weatherstripped, locked.... Windows* Non-weatherstripped, unlocked. Weatherstripped, unlocked......... 20 45 70 96 125 154 20 6 47 74 104 137 170 19 32 46 60 76 Rolled Section Steel ' Sash Windows* Industrial pivoted, Ms-in. crack*--. ...................... Architectural projected, Hz-in. crack"..................... Architectural projected, %4-m. crack"..................... Residential casement, M4-in. crack1......................... Residential casement, crack*....... #............... . Heavy casement section, projected, H-in. cracks Heavy casement section, projected, H*-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 76 100 128 18 26 36 48 38 54 72 92 ---- Hollow Metal, vertically pivoted window^.. 30 88 145 186 221 242 The values given in this table, with the exception of those for double-hung and hollow metal windows , are 20 percent less than test values to allow for building up of pressure in rooms, and are based on test data, reported in the papers-listed in chapter footnotes. . . .' 1. . b The values given for frame leakage are per foot of sash perimeter, as determined for double-hung wood windows. Some.of the frame leakage in masonry walls originates in the brick wall itself, and cannot be pre- ' vented by calking.. For the additional reason that calking is not done perfectly and deteriorates with time, ,s it is considered advisable to choose the masonry frame leakage values for calked frames as the average deter- * mined by the calke'd and non-calked tests. -. * c The fit of the average double-hung wood window was determined as Me-in. crack and ?tU-in. clearance - by measurements on approximately 600 windows under heating season conditions. ' d The values given are the totals for the window opening per foot of sash perimeter, and include frame V leakage and so-called elsewhere leakage. The frame leakage values included are for wood frame construction, : but apply as well to masonry construction assuming a 50 percent efficiency of frame calking. J e A sViQ- crack and clearance represent a poorly fitted window, much poorer than average. * Windows tested in place in building, so that no reduction from test values is necessary, as mentioned in ' - fo.o*tnIontdeuas.trial pivoted window generally used in industrial buildings. Ventilators horizontally pivoted . at center or slightlyabove, lower part swinging out. ' . -j h Architecturally projected made of same sections as industrial pivoted, except that outside framing mem ber is heavier, and it has refinements in weathering and hardware. Used in semi-monumcntal buildings ' such as schools. Ventilators swing in or out and are balanced on side arms. Ma-in. crack is obtainable in the_ best practice of manufacture and installation, %4-in. crack considered to represent average practice. . 1 Of same design and section shapes as so-called heavy section casement, but of lighterweight. M*~in. crack';, is obtainable in the best practice of manufacture and installation, Ms-in. crack considered torepresentaverage practice. ' 1 Made of heavy sections. Ventilators swing in or out and stay set at any degree of opening. H*-in. crackT '5 is obtainable in the best practice of manufacture and installation, Ms-in. crack considered torepresentaverage^ practice. <' * With reasonable care in installation, leakage at contacts where windows are attached to steel frame work and at muliions, is negligible. With M<-in. crack, representing poor installation, leakage at contact' \ with steel framework is about one third, and at mulliona, about one-sixtb of that given for industrial pivoted. windows in the table. . t- The amount of infiltration for various types of windows is given in Table- i 2.1 The fit of double-hung wood windows is determined by crack and/w clearance. Crack thickness is equivalent to one-half the difference be-/ f tween the inside window frame dimension and the outside sash width.The difference between the width of the window frame guide and thejjj sash thickness is considered as the clearance. The length of the perimeter*/?opening of crack for a double-hung window is equal to three times the width, plus two times the height, or in other words, it is the outer sash perimeter-/', lengt.h, plus the meeting rail length. All of the window crack in any given;/' Infiltration and Ventilation 221 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 de pends 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 labora tory, 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 average 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 properly fitted. Lock ing, a normal operation in the closing of this type of window, maintains the crack at a low value. . For 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 properly 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 muliions 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 reduction in infiltration is secured; the application of the sash provides an air space which reduces the heat transmission and helps prevent the frosting of the win dows.3 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 size and tendency to warp. For a well fitted door, the leakage, values for a poorly fitted double-hqng 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 which is frequently opened, as might be the case in a store, should have a value applied which is 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 windi est weather. The infiltration rate through swinging and revolving doors is generally a matter of judgment by the engineer making cooling load determinations, and in the absence of adequate research .data, the values given in Table 3 Represent current engineering practice. Some tests of infiltration through swinging and revolving doors have been reported.4. 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 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 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 num ber of air changes per hcmr for each room, the number of changes as sumed being dependent upon the type, use, and location of the room, as Table 3. Infiltration Through 72-Inch Revolving Door and 36-Inch Swinging Door*'5 (Cubic Feel per Person per Passage) Usage DooaFeebly-Revolving Heavy........................................... .................. 75 60 40 Doob Equipped with Brake 60 50 40 . .... 20 to 100 3. v. t '4 y. tip. 1; use inThoenseewSaglul roenslya.re Abansyedswoningthinegadsosourms pintioonththear wt tablelsreshisounlod wbeinkaepprtesclsousreedntuouinsure air cond_i_ti_o_n_i_n_g in a'ccobrdFarnocme AwpitphlicthaetsioenreEcnogminmeeenrdinegd Ssttaannddaarrddss. for A- ir Conditioning for Comfort 1947, Air Conditioning A Refrigerating Machinery Association, Inc., Washington, D. C. and from experimental data of National Bu reau of Standards. Used by permission. indicated in Table 4. Where it is not possible to determine or pre-determine with accuracy the width of crack or clearance of windows, or where 4: other sources of air leakage cannot readily be evaluated, as is often the ?x case, the use of the air change method may be justified.5 The values in Table 4 may be used with reasonable accuracy for resi- h dences, and are the requirements for each room. The total infiltration 4/ allowance for the entire building should be one-half the sum of the infil-'ti tration allowances of the individual rooms, since whatever air enters on thevtj windward side, generally leaves the building on the leeward side, and the|& infiltration requirements therefore do not exist simultaneously on all'll sides; or in all rooms. An allowance of one air change per hour for ally?.1 sources of air leakage for the entire volume may be considered average,^? for a well constructed residence. The air leakage, due to opening and closing of doors in vestibules, i||;l 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 reception halls, it is not advisable to attempt to apply thefa air change method to factories and industrial and commercial building^ because'of wide variations in the type and percentage of fenestration wbicrntT is the principal source of air leakage in such buildings. ' Infiltration and Ventilation 223 The air exchange due to temperature difference, inside to outside, is a chimney effect, causing air to enter through openings at lower levels, and to leave at higher levels6 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 open ings near the ground level and near the ceiling; it should also be considered in tall, multi-story buildings 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 attic. It can best be understood by visualizing the building 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 Res,dences. Exclustiavkeinogf Ai-liracPeruonvdideerd AfvoerraVgeentCiloantdioitnio* ns in Kind of Room or Building Number or Air Changes taking Place per Hour Kin of Room or Building Number of Air Changes taking Place per Hour Rooms, 1 side exposed____ Rooms, 2 sides exposed___ Rooms, 3 sides exposed__.. Rooms, 4 sides exposed T m 2 2 Rooms with no windows or outside doors Entrance Halls.... Reception Halls... Bath Rooms........ Mto H 2 to 3 2 2 less tha" iaTM"angCW"thCnitnPPed w,IldoW3 0r storm these values, where applicable, but uever ----------- . moves ujiwaru unrougn cracKS ana open ings 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 communicate with the outside through cracks and fissures. The ceiling acts as another damper with air flowing upward through various cracks and openings. This condi tion 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 construction. Since the chimney effect in a building produces a negative pressure and an inward flow of air at the lower levels and positive pressure and outward now at the higher levels, a neutral zone7 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 through openings in the outside walls as a result of temperature differences. The infiltration caused by the indoor-outdoor temperature differences an be calculated by means of the crack method described earlier in this chapter for determining the infiltration caused by wind pressure. This is one by determining the equivalent wind velocity that would produce the me rate of infiltration as was caused by the prevailing temperature difcrenee. It is recommended that one-half the total crack length of the building be used for this computation.. To determine the infiltration caused by the temperature difference, one-half the crack length of the building is multiplied by the infiltration coefficient from Table 2 corresponding to the equivalent wind velocity computed from the following equation developed from basic relationships between velocity, presaute, density' and tempera ture. W = B\/h(ti -- to) (1) where Vo -- equivalent wind velocity corresponding to the temperature difference (ti -- to), miles per hour. h = height of rooms, feet. fi = inside temperature, Fahrenheit. .t . . f0 = outside temperature, Fahrenheit. i, B -- a constant to account for leakage through floor and ceiling and for the num ber of stories in the building. i s 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 was 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 the number of stories in creased, and for stories farther removed from the neutral zone in either direction in buildings that lacked perfect sealing between stories. Sealing of Vertical Openings In tall, multi-story buildings, every effort should be made to seal off ;?7J vertical openings, such as stair-wells and elevator shafts, from the remainder; /'I of the building. : Stair-wells should be equipped with self-closing doors, and, in exceptionally high buildings, should be closed off into sections of (V not over 10 floors each. Plaster cracks should be filled. Elevator en-;g.' I closures should be tight, and solid doors should be used.. . s fe-j If the sealing of the vertical openings is made effective, no allowance, need be made for the chimney effect. Instead, the greater wind move-'(.cil ment at the greater heights makes it advisable to install additional heating iff surface on the upper floors above the level of neighboring buildings, this' ;-v additional surface being increased as the height is increased. One arbi- gj trary rule is to increase the heating surface on floors above neighboring j buildings by an amount ranging from 5 percent to 20 percent. This extra.;?!-:, heating surface is required only on the windward side and on windy days/;);:; and hence/ automatic temperature control is especially desirable with such'f-ff installations.: '4*1 In stair-wells that are open through many floor levels, although closed ) ' off from the remainder of each floor by doors and partitions, the strati fication <jf 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,,"yd is to calculate the heating surface of the entire stair-well in the usual way,;.f -.1 and to place 50 per cent of this in the bottom third, the normal amount^?: in the middle third, and the balance in the top third Infiltration and Ventilation Infiltration and Air for Combustion 225 Infiltration in buildings normally supplies the air required for combus tion by fuel-burning appliances, but in some cases weatherstripping, 'Seal ing and calking may reduce infiltration to the point that special openings must be provided to supply adequate air. to the heating appliances. Thus 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 Dwellings8, requires that ah 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 same code for multiple Fig. 2. Th. e Jump op Wind . prom Windward Face/To7p VB7uTilding. B--(A--Length op Suction Area; Point op Maximum Intensity C--of Suction; Point op Maximum Pressure) . dwellings requires a permanent opening to the outdoor, air for rooms con taining fuel-burning appliances having a gross capacity, in excess of 250,000 Btu per hour. ... . - NATURAL VENTILATION , Ventilation by natural forces finds application in industrial plants, Public buildings, schools, dwellings, garages,-and in farm buildings. , ljhe natural forces available for moving air into, through, and out of wildings are; (a) wind forces, and (b) the difference in temperature p W,?jn the air inside and outside a building. The air movement may be ky either of these forces acting alone, or by a combination of the .0> depending upon atmospheric conditions, building design, and location. 226 CHAPTER 11 1954 Guide M The ventilating results obtained will vary, /rom time to time, due to varia tion in the velocity and direction of the wind, and the temperature difference. The arrangement, location, and control of the ventilating openings should be such that the two forces act cooperatively rather than in opposition. WIND FORCES In considering the use of natural wind forces for producing 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. VVaalluueess aarree ggiivveenn iinn Tiaaobilee 3o,, Chapter 13 for the a--v-e--r-a-gDe_ w__in__d velocities for the months June to September in various localities throughout the /s 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 direc tion 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 onehalf 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 AQ == afriereflaorwe,acoufbiinclefeteotppeenrinmgsin, ustqeu. are feet. V = wind velocity, feet per minute, = miles per hour X 88. |/j B E = effectiveness of openings. (E should be taken at 0.50 to 0.60 for perpendicu-yf, lar winds, and 0.25 to 0.35 for diagonal winds.)' fl 'y The precision of results obtained by the use of Equation 3, depends// upon the placing of the openings, as the formula assumes that ventilatinglf openings have a flow coefficient slightly greater than that of a square-H 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 and, if un-|g usually well placed, the flow will be slightly more than that given by th'%; formula. Inlets should be placed to face directly into the prevailing wirid^f while outlets should be placed in one of the five places listed: j| 1. On the side of the building directly opposite the direction of the prevailing wind^ 2. On the roof in the low pressure area caused by the jumpof the wind (see Fig. 2)/.| 3. On the sides adjacent to the windward face where low pressure areas occur./f 4. In a monitor on the side opposite from the wind. R T" roof ventilators or stacks. 5. In roof ventilators or stacks. tjj |L*| TEMPERATURE DIFFERENCE FORCES7 The stack effect produced within a building, when the outdoor temperam-1, ture is lower than the indoor temperature, is due to the difference in weight;/ ' ' '.V'H Infiltration and Ventilation 227 of the warm column of air within the building and cooler air outside. The flow due to stack effect is proportional to the square root of the draft head, or approximately Q = 9.44 VMfi - (,,) (4) where Q -- air flow, cubic feet per minute. A = free area of inlets or outlets (assumed equal), square feet. h = height from inlets to outlets, feet. U = average temperature of indoor air in height h, Fahrenheit. t0 = 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 con ditions are not favorable. HEAT REMOVAL In problems of heat removal, knowing the amount of heat to be removed and having selected a desirable temperature difference, the amount of air to be passed through the building per minute, to maintain this tempera ture difference, can be determined by means of Equation 5. where JJ ^ " 0.0175 (l, - to) (5) Q = air flow, cubic feet per minute. H = beat removed, Btu per minute. fi -- <,, = inside-outside temperature difference, Fahrenheit. EFFECT OF UNEQUAL OPENINGS The largest flow per unit area of openings is obtained when inlets and outlets are equal, and the preceding equations are based on this condition. Increasing outlets over inlets, or vice-versa, will increase the air flow, but not in. proportion to the added area. When solving problems having an unequal distribution of openings, use the smaller area, either inlet or out let, in the equations, and add the increase as determined from Fig. 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 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 open ings 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 independently under conditions ideal to it. This percentage de creases 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 r.eS>.*iSvr" 4. . 228 CHAPTER 11 1954 Guide distribution, cannot. be predicted with certainty, and refinement, in calcu lations is not justified; consequently, a simplified method-can be used. This may be done by using the equations and calculating the flows produced by each force separately, under conditions of openings best suited for co ordination of the forces. Then, by determining the ratio of the flow pro duced 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 shop, 200 ft long, 100 ft wide, and 30 ft high. The cubical content is 600,000 cu ft, and the height of the air 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 difference is 10 deg, and the prevail ing wind is 8 mph perpendicular to the long dimension. What is the necessary area for the inlets and outlets, and what is the rate of air flow through the building? ft of opening in its path for inflow, and 612 in the lee side of the monitor for outflow, with the windward side closed. The air flow, as calculated by Equation 3, will.be: Q = 0.60 X 410 X 704 = 173,200 cfm. This gives 17.3 air changes per hour, which should be more than ample when there is no heat to be removed. , ; < Solution to Combined Heads: Since the windward side of the monitor is closed when the wind is blowing, the flow 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 1,224 sq ft in the sidewalls ahd:612.sq,ft:in the monitor, the flow will be increased 26.5 percent over that produced by equal openings. Using Fio. 3. Increase in Flow Caused by Excess of One Opening Oveb Anotheb Solution for Temperature Difference Only: The heat H = **** * ' *. ' ' - - * Ov 34,875 Btu per min. . 18,000 ^ - * li By Equation 5, the air flow required to remove this-heat with an average temper1-^ ature difference of 10 deg is H 0.0175(1: - to) 34,875 0.0175 X10 199,286 cfm. This is equal to about 20 air changes per hour. From Equation 4, the inlet (or outlet); opening area should be . .. - qt 199,286 A= = 1224 sq ft. 9.4VA(ti - to) 9.4x/30 X 10 The flow per square foot of inlet or outlet would be 199,286 + 1224 = 163 cfm, with alt windows open. ; Solution for Wind Only: With 1,224 s<j ft of inlet openings distributed around the] sidewalls, there will be about 410 sq ft in each long side and 202 sq ft in each end.j The outlet area will be equally distributed on the two sides of the monitor, or 612,831 ft on each side. With the wind perpendicular to the long side, there will be 410 sijS . .. nation of Flow Caused by Combined Forces of Wind ' and Temperature Difference .. : the smaller opening and the flow per square foot obtained previously, the calculated amount for this condition will be . . 612 X 163 X 1.265 = 126,200 cfm. Adding the two computed flows: Temperature Difference = 126,200 = 42 percent. Wind = 173,200 = 58 percent. Total 299,400 = 100 percent. From Fig. 4 it is determined that, when the flow due to temperature difference is 42 percent of the total, the actual flow due to the'combined' forces, will be about 1.6 bmes that calculated for temperature difference alone, or 201,920 cfm. - : The original flow, due to temperature difference alone was 199,286 cfm with all openings in use. The effect of the wind is to increase this to 201,920 cfm, even though "Rif of the outlets are closed. ' A factor of judgment is necessary in the location of the openings in a budding, especially those in the roof, where heat, smoke, and fumes are to be removed. Usually, windward monitor Openings should be closed, but if 230 CHAPTER 11 1954 Guide the wind is low enough for the temperature head to overcome it, all windows ft 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 designed inlet or outlet openings. The various types and principles of operation are discussed in following paragraphs. Windows, Doors and Skylights 'Window s have the adva- ntage of transmitting light, as well as providing jv ventilating area, when open. Their movable parts are arranged to open Jg 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 ft pivots at the top, bottom or side. Regardless of their design, the air 'ft;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 ad- ft- vantageous in controlling the distribution of incoming air. Deflectors st are sometimes used for the same purpose, and these devices should be con- .-5 sidered a part of the ventilation system. M Roof Ventilators The function of a roof ventilator is to provide a storm and weather proof air outlet. These are actuated by the same forces of wind and tem- -V perature head which create flow through other types of openings. The .ft capacity of a ventilator depends upon four things: (1) its location on theft roof; (2) the resistance it and the duct work offer to air flow; (3) the height ||| of draft; and (4) the efficiency of the ventilator in utilizing the kinetic gjj energy of the wind for inducing flow by centrifugal or ejector action. For maximum flow induction, a ventilator should be located on that's; part of the roof where it will receive the full wind without interference.ftf 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 between^ two high buildings, their performance will be seriously influenced. Theirftt normal ejector action, if any, may be completely lost. J The base of the ventilator should be of a taper-cone design to producejft 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 atol the base, or if the base of structural members present obstructions, addirjfr tional resistance is introduced, and the base opening should be increased*?; in Asizire ianclectorodpinegnliyn.gs located at lower levels in the building, should be aift least equal to, and preferably larger than, the combined throat areas ofjf| all roof ventilators. The air discharged by a roof ventilator depends 01& wind velocity and temperature difference, and, in general; its performance* will be the same as any monitor opening located in the same place but, duft to the four capacity factors already mentioned, no simple formula can bfg 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 continuousftSj ridge ventilator would fall in the stationary classification. When selecting?! roof ventilators, some attention should be given to ruggedness of construe;-: Infiltration and Ventilation 231 tion, storm-proofing features, dampers and damper operating mechanisms, possibility of noise, original cost, and maintenance. 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 hand, 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. Stacks Stacks or vertical flues_are really chimneys which function through the effects of the wind and temperature difference. Like 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 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 out lined, 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 lee ward side near the top. Outside air will then be supplied to the zone to be ventilated. 2. Inlet openings should not be obstructed by buildings, trees, sign boards, etc., outside, nor by partitions inside. 3. Greatest flow per square foot of total opening is obtained by using inlet and out let 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 orientation of the building, together with amount ,6rouP'8 of ventilation openings, can be readily arranged to take full advantage of the force of the wind. Where the wind's direction is quite variable, the openings should be arranged in sidewalls 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 oc cupancy. order that temperature difference may produce a motive force, there must be ahl Ca' d'3tance between openings. That is, if there are a number of openings avail- ole m a building, but all are at the same level, there will be no motive head produced y temperature difference, no matter how great that difference might be. lo order that the force of temperature difference may operate to maximum adPoss'h?6' t*le Vf'r'ica] distance between inlet and outlet openings should be as great as i-ioii > e Openings in the vicinity of the neutral zone are less effective for ventila- clos .ft use monitors, windows on the windward side should usually be kept ed, since, if they are open, the inflow tendency of the wind counteracts the outflow 232 CHAPTER 11 1954 Guide 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 prevail ing wind. The strong suction effect of the wind at the roof near the windward end wili then cooperate with temperature difference, 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 windward end, that part of the building in which they are to be located should be built higher than the rest, so that the wind, in splashing therefrom, will create a suction. The additional 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, espe cially when an increase in occupancy may occur, or when extremely hot days may be anticipated. In the former case, free openings should be located at the level of occu pancy for psychological reasons. . 13. In single story industrial buildings, particularly those covering large areas, natural ventilation must be accomplished by taking air in and out of the roof open ings. Openings in the pressure zones can be used for inflow, and openings in the sue-' tion zone, or openings in zones of less pressure, can be used for outflow. The ventila tion is accomplished by the manipulation of openings to get air flowthrough the zones to be ventilated. VENTILATION OF ANIMAL SHELTERS10 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 found or approximately square. A thermal resistance (1/(7) of not less than two is required in their side walls. They should extend at least two feet above the highest part of the roof. Only one outlet is recommended for each room or pen. The use of several outlet flues may result in excessive: up-drafts in some flues, and down-drafts in others. . If flues have roofs or covers, these should be high enough to provide' unobstructed openings on all sides, 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.asj to avoid drafts on the animals, and to insure immediate mixing of incoming air with the room air. A reasonably uniform distribution around the' stable or pen is desirable. Inlet flues, that deliver air close to the side walls,';: stimulate convection currents, which is desirable. When so placed, they als$ tend to bathe the side walls with cool air, thus reducing temperature differ-.- ence between the inside and outside of the wall. -1, 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. Ho used, they are best applied to the inlets and limited to the side of thebuilding 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', remAaminouonptesn.of heat and water produced by livestock vary not only with;, the different kinds of animals, but also with age, weight, feed consumption^and production. These facts, and the vagaries of the weather, make exact " Infiltration and Ventilation :233 calculations impossible. 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 in the discussion!or each kind of animal. ' - ; Dairy Stables The most usually accepted temperatures for dairy stables, where cows are confined in stanchions or tie stalls, are from 45 to 55 F. These tempera tures are readily maintained 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 re- Fig. 5. Recommended Type op Cover for Wooden Outlet Flue t,s esTsheentoiaple. ning H ebould equal on*e-half the least dimension of the flue. Heavy insulation of the level deck sistance of the ceiling should be 50 percent greater than that of the side walls. In stables of this size and so insulated, a ventilation rate of 3200 to 3800 cu ft per (hr) (1000 lb of animal) usually insures good conditions. . The following,recommendations do not apply to so-called peri stables or loafing bains 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 long, the flue should be about midway between the ends or, if the stable is L-shaped, near the angle. In shorter stables, it inay be at any con venient 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 temperature. ` A basic rule for finding the cross-section of the outlet flue is , where ~ ' . . 176 N Vh ~ : . - -- -A 0 area of the outlet flue, square inches. (6) N = weight of animal population, thousands of pounds. . h = vertical distance from top of inlet flues to top of outlet flue, feet. For large flues the flue area obtained from the basic formula may well be reduced according to the chart, Fig. 6, because of a decrease in friction. Example 2: Assume a stable in which the verti.cal 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. f; Solution: From Equation 6 A. = 176 X (38 X V32A 1300) = 1525 sq in. From Fig. 6 the factor to be applied to this area is 94.5 percent. Therefore, the area of flue 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. - . fvue AREA AS CM.CUCATU* -ieww . Modification of Flue Area for Outlets Exceeding 1000 Sq In. Sheep Barns Shelters used for breeding and feeding, stock usually have enough open ings, so that no special provision for ventilation is required. Bams for win ter lambing 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. Outlets. In practice, results obtained by the basic formula, Equation 7, when modified by the use of the: chart, Fig. 6 have given good re sults : 4A( A " a/S (7) where A,, = area of the outlet, square inches. A i = floor area, square feet. 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 Infiltration and Ventilation 235 area. Inlets should be well distributed around the side walls, and de signed 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 daily 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 recommended 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 resistance 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, Ao= 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 re quired, and the number that can be so installed as to meet previous speci fications. Inlets should deliver air from points 12 to 15 in. below the ceil ing, or from a level deflector on a sloping ceiling. Poultry Laying Houses From the standpoint of ventilation, poultry laying houses may be di vided into cold houses and warm houses. The former are uninsulated, except in the ceiling. The inside-outside temperature difference is seldom more than 5 F deg. In the warm house, because of insulation or supple mental 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. 2.5 x A, 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 flue 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 nrea may be equal to 70 percent of the outlet area. Inlets in cold and in 'varm 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 .236 CHAPTER 11 1954 Guide & 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 physi- 7 ologically harmful or combustible gases or vapors in garages, the importance of proper ventilation of these buildings cannot be over-emphasized. Dur ing the warm months of the year, garages are usually ventilated adequately because the doors and windows are kept open. The A.S.H.V.E. Code of : Minimum Requirements for Heating and Ventilating Garages,11 adopted in 1935, specifies that openings for natural ventilation shall be distributed ? as uniformly 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, dis charging it to the outside as a means of flushing the garage. ' Cooperative research11 on garage ventilation, undertaken by the 1 A.S.H.V.E. Committee on Research at Washington University, St. Louis, Mo., and at the University of Kansas, and tests conducted at the A.S.H.V.E. ' Research Laboratory, have resulted in authoritative papers on the subject. ' Some of the conclusions based on work at these laboratories are: . 1. Upward ventilation results in a lower concentration of carbon 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. V 2. A lower rate of air change and a smaller heating load are required with upward ( than with downward ventilation. ., 3. In the average case, upward ventilation results in a lower concentration of ,r carbon monoxide in the occupied portion of a garage, than that obtained with mixing % of the exhaust gases and the air supplied. However, the variations in concentration 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,;' and 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 mon oxide 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 outdoors. 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 attached-^ to the tail pipe. The minimum branch size and ventilation rate for thfig; largest class of-vehicle regularly serviced at each location are shown in-1 Table 4. ^ Where each tail pipe exhaust branch is provided with an automatic de-1.;. vice to close the branch inlet when it is not in use, the capacity of the fanf for the system should be based on the maximum number of branches simultaneous use. Where the branch inlets are open when not in use, tlw; t' - Infiltration and ventilation Class of Vehicle Tail Pipe Diameter, in. Bus.................... . Under 2 . 2 to 3 3 and over Ventilation Rate, cfm 100 150 250 Flexible Pipe, Diam, in. I Diameter op Rigid Branch Connection, to "Flexible Pipe, in.' 3 4 : i'A '4 i'A 5>g system capacity should be based on the total number of branches connected to the main. Individual straight lengths of gas tight duct, not over 20 feet 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 diam eter not less than the diameter of the tail pipe. . REFERENCES 1 A.S.H.V.E. Research Report No. 786--Infiltration Through Plastered and Unplastered'Brick Walls, by F. C. Houghten and Margaret Ingels (A.S.H.V.E. Transactions, Vol._ 33, 1927, p. 377). No. 826--Air Infiltration Through Various Types of Brick Wall Construction, by G. L. Larson. D. W. Nelson and C. Braatz (A.SM.V.E. Transactions, Vol. 35,1929, p. 183). No. 851--Air Infiltration Through Various Types of Brick Wall Construction, by G. L. Larson, D. W. Nelson and C. Braatz.(A.S.H.V.E. Transactions, Vol. 36, 1930, p..99). No. 868--Air Infiltration Through Various Types of Wood Frame Construction, by G. L. Larson, D. W. Nelson and C. Braatz (A.S.H.V.E. Transactions, Vol. 36, 1930, p. 397). ' * A.S.H.V.E. Research Reports No. 686--Air Leakage, by F. C. Houghten and C. C. Schrader (A.S.H.V.E. Transactions, Vol. 30, 1924, p. 105). No. 704--Air Leakage Around Window Openings, by C. C. Schrader (A.S.H.V.E. Transactions, Vol. 30, 1924, p. 313). No. 803--Air Leakage on Metal Windows in a Modern Office Building, by F. C. Houghten and M. E. O'Connell (A.S.H.V.E. Transactions, Vol. 34,1928, p. 321). No. 815--Air Leakage Through a Pivoted Metal Window, by F. C. Houghten and M. E. O'Connell (A.S.H.V.E. -Transactions, Vol. 34, 1928, P- 519). No. 817--Effect of Frame Calking and Storm Sash on Infiltration Around and Through Windows, by W. M. Richtmann and C. Braatz (A.S.H.V.E. Transac tions, Vol. 34,1928, p. 547). No. 909--Air Infiltration Through Double-Hung Wood Windows, by G. L. Larson, D. W. Nelson and R. W. Kubasta (A.S.H.V.E. Trans actions, Vol. 37,1931, p. 571). The Weathertigbtness of Rolled Section Steel Win dows, by J. E. Emswiler and W. C. Randall (A.S.H.V.E. Transactions, Vol. 34, i"8. p. 527). Pressure Differences Across Windows in Relation to Wind Velocity, cy J. E. Emswiler and W. C. Randall (A.S.H.V.E. Transactions, Vol. 36, 1930, p. <) Air Infiltration Through Steel Framed Windows, by D. O. Rusk, V. H. Cherry and L. Boelter (A.S.H.V.E. Transactions, Vol. 39, 1933, p. 169). ' Fuel Saving Resulting from the Use of Storm Windows and Doors, by A. P. Rratz and S. Konzo (A.S.H.V.E. Transactions, Vol. 42, 1936, p. 87). , ' The Infiltmtion Problem of Multiple Entrances, by A. M. Simpson and K. B. Atkinson (A.S.H.V.E. Journal Section, Heating, Piping and Air Conditioning, Junei 1936, p. 345). Infiltration Characteristics of Entrance Doors, by A. M. Simp- sn (Refrigerating Engineering, June, 1936). , * Indices of Air Change and Air Distribution, by F. C. Houghten and J. L. Blacksnaw (A.S.H.V.E. Transactions, Vol. 39, 1933, p. 261). T, A.S.H.V-.E. Research Reports No. 994--Wind Velocities Near a Building and ,A^!r Effect on Heat Loss, by F. C. Houghten, J. L. Blackshaw and Carl Gutberlet If t'-H.V.E. Transactions, Vol. 40,1934, p. 387). No. 1069--Heating.Requirements P Office Building as Influenced by the Stack Effect, by F. C. Houghten and Carl n!y."rlet (A.S.H.V.E. Transactions, Vol. 43, 1937, p. 437). Flue Action in High Cntj.11?8'. fiy H. L. Alt (A.S.H.V.E. Journal Section, Heating, Piping and Air t!?i i11"' May, 1932, p. 376). Influence of Stack Effect on the Heat Loss in ^.Buildings, by Axel Marin (A.S.H.V.E. Transactions, Vol. 40, 1934, p. 377). v . Neutral Zone in Ventilation, by J E Emswiler /A.S.H.V.E. Transactions, vl. 32,1926, p. 59). 238 CHAPTER 11 1954 Guide # 8 State Building Construction Code Applicable to One- and Two-Family Dwellings, Stale Building Code Commission, 1740 Broadway, New York/19, N- Y. 9 Predetermining Airation of Industrial Buildings, by W. C. Randall and E. W. Conover (A.S.H.V.E. Transactions, Vol. 37, 1931, p. 605). 10 Dairy Barn Ventilation, by F. L. Fairbanks (A.S.H.V.E. Transactions, Vol. 34, 1928, p. 181). Cow Barn Ventilation, by Alfred J. Offner (A.S.H.V.E. Trans actions, Vol. 39, 1933, p. 149). For additional information on this subject refer to Technical Bulletin, V- S. Department of Agriculture (1930), by M. A. R. Kelley. Also see Air Conditioning of Farm Buildings, by F. L. Fairbanks (Agricultural Engineer ing, November, 1937, p. 485), Dairy Stable Ventilation (Revision of 1949) by F. L. Fairbanks and A. M. Goodman (Cornell University, Cornell Extension Bulletin No. 151) and The Ventilation of Poultry Laying Houses (Revision of 1950) by F. L. Fairbanks and A. M. Goodman (Cornell University, Cornell Extension Bulletin No. ' 3151)1.Code of Min.imum Requirements for Heating and Ventilating Garages (A.S.H.V.E. Transactions, Vol. 41,1935, p. 30). Airation Study of Garages, by W. C. Randall and L. W. Leonhard (A.S.H.V.E. Transactions, Vol. 36, 1930, p. 233). A.S.H.V.E. Research Report. No. 874--Carbon Monoxide Concentration in. Garages, by A. S. Langsdorf and R. R. Tucker (A.S.H.V.E. Transactions, Vol. 36, 1930, p. 511). A.S.H.V.E. Research Report No. 935--Carbon Monoxide Distribu tion in Relation to the Ventilation of an Underground Ramp Garage, by F. C. Houghten and Paul McDermott (A.S.H.V.E. Transactions, Vol. 38,1932, p. 439). A.S.H.V.E. Research Report No. 934--Carbon Monoxide Distribution in Relation to the Ventilation of a One-Floor Garage, by F. C. Houghten and Paul McDermott (A.S.H.V.E. Transactions, Vol. 38, 1932, p. 424). A.S.H.V.E. Research Report No. 967--Carbon Monoxide Distribution in Relation to the Heating and Ventilation of a One-Floor Garage, by F. C. Houghten and Paul McDermott (A.S.H.V.E, Transactions, Vol. 39, 1933, p. 395). Carbon Monoxide Surveys of Two Garages, by A. H. Sluss, E. K. Campbell and Louis M. Farber (A.S.H.V.E. Transactions, Vol. 40, 1934, p. 263). bibliography Garage ventilation Experimental Studies on the Effect of Ethyl Gasoline and its Combustion Prod- V ucts, by R. R. Sayers, A. C. Fieldner, W. P. Yant and B. G. H. Thomas (V. S. Bureau of MVeinnetsilaMtioonnogorfapVhehNicou. l2a,r1T9u2n7)n. els, by A. C. Fieldner, Yandeil Henderson, J. W. . Paul, R. R. Sayers, et al (A.S.H.V.E. Journal. Section, Heating Piping and Air Con- , ditiUosneinogf,DJiaens.e-Dl Eeen.gi1n9e2s6)in Tunnels, by S. H. Ash and L. L. Naus (U- S. Bureau of .. Mines Information Circular No. 7222, 1942). `; Ventilation Involved in the Use of Gasoline Powered Equipment in Enclosed Spaces, by L. B. Berger (U. S. Bureau of Mines Information Circular No. 7494, 1947),', ' Diesel Engines Underground: Composition of Exhaust Gas from Engines in Proper. Mechanical Condition, by J. C. Holtz, L. B. Berger, M. A. Elliott and H. H. Schrenk (U. S. Bureau of Mines Report of Investigations No. 3508, 1940). Diesel Engines Underground: Use of Diesel Locomotives in Construction of the Delaware Aqueduct: Effect of Exhaust Gases upon Quality of Tunnel Air, by L. B. Berger, M. A. Elliott, J. C. Holtz and H. H. Schrenk (U. S. Bureau of Mines Report - of Investigations No. 4032, 1947). CHAPTER 12 HEATING LOAD General Procedure, Design Outdoor Weather Conditions, Inside Temperatures, Attic Temperatures, Temperatures in Unheated Spaces, Ground. Tempera-, tures, Basement Temperatures and Heat Loss, Heat Losses from Floor Slabs, Transmission Heat 'Loss, Infiltration Heat Loss, Selection of Wind Velocities, Auxiliary Heat Sources, Intermittently Heated Buildings, Residence Heat Loss Problems PRIOR to designing a heating system, an estimate must be made of the maximum probable beat loss of each room or space to be heated, based on maintaining a selected inside air temperature during periods of design outdoor weather conditions.: The heat losses may be divided into two groups, namely: .(1) the transmission losses or heat transmitted through the confining walls, floor, ceiling, glass or other surfaces; and (2) the in filtration losses or heat required to warm outside air which leaks in through cracks.and crevices, around doors and windows, opening of doors and win dows, or heat required to warm outside air used for ventilation. GENERAL PROCEDURE The general procedure for calculating heat losses of a structure is: 1. Select the design outdoor weather conditions: temperature, wind direction and wind velocity. The data on climatic conditions given in Table 1 and the isotherms of average design temperature in Fig. 1 will be helpful, but should be used with judg ment as suggested in the section Design Outdoor Weather Conditions. 2. Select the inside air temperature, which is to be maintained in each room during the coldest weather. (See Table 2). 3. Estimate temperatures in adjacent unheated spaces and the attic. The attic temperature need not be estimated if the combined roof and ceiling coefficient is used. 4. Select or compute the heat transmission coefficients for outside walls and glass; also for inside walls, floors, or top-floor ceilings, if these are next to unheated space; include roof if next to heated space. (See Chapter 9. If the design wind velocity 18 appreciably different from 15 mph, the appropiiate change in the heat tiansmission coefficients in Tables 6 to 9 and 15 to 19 of Chapter 9 can be found in Table 21 of that chapter.) 5. Measure net area of outside wall, glass and roof next to heated spaces, as well as any cold walls, floors or ceilings next to unheated space. Such measurements are Iade from building plans, or from the actual building, using inside dimensions. 6. Compute the heat transmission losses for each kind of wall, glass, floor, ceiling and roof in the building by multiplying the heat transmission coefficient in each case ?y the area of the surface in square feet, and the temperature difference between the inside and outside air. (See Items 1, 2, and 3). Ja 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 velocity, and the temperature difference between the inside and outside air; the result expresses the heat required to warm up the cold air making into the building per hour. (See Chapter U). 8. When positive ventilation using outdoor air is provided by an air heating or an V conditioning unit, the heat required to warm the outside air to room temperature must be provided by the unit; if mechanical exhaust from the room is provided, in 'nunt. equal to the outside air drawn in by the unit, the natural infiltration losses must also be provided for by the unit. If no mechanical exhaust is used, and the : 239 240 CHAPTER 12 1954 Guide 1 outdoor air supply equals or exceeds the amount of natural infiltration which would 1 occur without ventilation, the natural infiltration may be neglected. ' 9. The sum of the heat losses by transmisions (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 cold air entering by infiltration, or required to replace mechanical exhaust, represents the total heat loss equivalent for any building. . 10. In buildings which have a reasonably steady internal heat release of appre ciable magnitude from sources other than the heating system, a computation of this heat 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 sys tems of high initial cost or those for which a demand charge is based on installed capacity. .' DESIGN OUTDOOR WEATHER CONDITIONS - There are no hard and fast rules for selecting the design outdoor weather conditions to be used for a given locality or type of building or heating system, and the selection is to some extent a matter of judgment arid experience. The appropriate design temperature in a given locality may vary with heat capacity and degree of insulation of a particular structure, the amount of protection from the wind, the lengthof time that nightly minimum tempera tures persist, whether the particular building is being used day and night, and perhaps other factors. For heating systems that depend primarily on . . - electrical energy as a source of heat it will often be desirable, for economic reasons, to make a more careful analysis of the factors that affect design . weather conditions than would otherwise be justified. The outside design temperature seldom is taken as the lowest tempera-. ture, or even the lowest daily mean temperature ever recorded in a given locality. Such temperatures rarely recur in successive years. Likewise the wind direction and velocity occurring at the time of design outside tempera ture may be different from the average velocity and prevailing direction during the. winter. .' - The A.S.H.V.E. Technical Advisory Committee on Weather Design, Conditions has recommended the adoption for heating load calculations , of an outside design temperature which is equalled or exceeded during 97\ percent of the hours in December, January, February and March. Complete - ' design temperature data based on this formula are not available, but Col umn 8, Table 1, lists this recommended design temperature based'on airport station readings for the period indicated, generally the five years, 1935- \ 1939. In most cases these stations are outside of the city and these data g apply primarily to rural areas. In general the use of the airport data for .. buildings within an adjacent city will not make an appreciable difference in : design load. is. Because of the limited data available in Column 8 of Table 1, design v temperatures in common use are listed in Column 10, Many of those values were furnished by A.S.H.V.E. members, the remainder were taken> from an ACRMA Bulletin,1 manufacturers' publications, and other sources,? ; , and a few were estimated. . - The map in Fig. 1 shows isotherms of outdoor winter design temperature ; which are based on the values in Column 10 of Table 1 with some modifies-. tions where other data indicated that Column 8 furnishes a more reasonable i design temperature. These isotherms have also been modified slightly inV. accordance with the elevations of the various cities. The isotherms are .y. drawn on 10 deg temperature intervals, in most cases, and are so placed that interpolation between isotherms will provide the proper design temper-m ature for cities between the isotherms. Thus, a city located half-way be- Heating Load Col. 1 Col. 2 Station6 -241 Table 1. Winteb Climatic Conditions* Col. 4 Record" Col. 5 Low- EST Temp. ON ' Rec ord" Col. 6 Col. 7 Col. 8 Col. 9 Col. IO.'Col. 11 Avbb- Design DE82GN age . An- B *Avo. Win- Dby- ulb Wind m% Temp- ,NTJAL Min. TEH Temp/ Temp at onTAC _PE8io.n Temp. Ala.,.. Anniston.............. Q 1893-1947 Birminghamc 1893-1945 Birmingham........... A 1939-1947 Mobile.......... V* 1872-1947 Mobile.:................ " `a 1940-1947 Montgomery........... .c 1872-1947 Montgomery........ A Ari*.,.. Flagstaff................ ..'c 1938-1944 1899-1947 Kingman.............. a 1935-1939* Phoenix..................'c 1895-1947 Phoenix..................'"a . 1937-1947 Tubson........... q IUp to 1946 Ark.. Tucson.2551 ..................... c| 4853 Winslow a Yuma....;;;;;;;;;c Fort Smith........ C 1935-1939d Up to 1946 1932-1947 1876-1946' 1882-1945 Fort Smith....... A Little Rock........ C 1945-1947 1879-1942 Cal. Little Rock..............a Bakersfield........... A 499 Burbank................. 'a '740 1942-1947 1937-1946* 1931-1947 Daggett .A Eureka..................... Fresno................C Frespo........... . . . . a Los Angeles............,c Oakland.. ... a Red Bluff............. c Red Bluff......... a .......... ''.''.A 1925 115 387 281 534 21 341 346 579 1935-1939* 1886-1947 1887-1939 1939-1947 1877-1947 1929-1947 1877-1934 1944-1947 1935-1939* fcacramento...........C Sacramento.............. A San Diego.................q San Diego............ !!jT 116 22 90 34 J877-1947 1938-1947 1871-1940 1939-1947 aan hrancisco.........C kan Jose... n. Col... Williams.......... a Denver....... ' ''' q Denver........ A Grand Junction. . .C Pueblo......... r Conn., Pueblo......... .......A Hartford............... o Hartford..... . . . . A New Haven___ C D.c.: New Haven...........A Washington............C Ha... Washington............A Apalachicola.......... C Jacksonville........... .C Jacksonville.. Key West. A c 116040c 124 5398 5379 4587 4770 4810 229 20 180 17 128 20 23 104 29 23 1875-1947 Up to 1946 1935-1939 1871-1947 1934-1947 1889-1945' 1889-1938' 1939-1947 1905-1940 1940-1947 1872-1948* 1943-1947 1871-1947 1935-1939* 1922-1947 1871-1947 1938-1947 1871-1947 48 1939-1947 Ga..,. Miami.............. Pensacola..!!!!... C Pensacola............ a Tampa!.................. V Titusville ...............aI 253 13 67 111113 12 52 1896-1947 1940-1947 1879-1947 1943-1047 1890-1940* 1941-1946 1935-1939* 1878-1945* Idaho Aogusto.;;;;;;9 m Macon p Macon. !!!..!!!' a Savannah.. Savannah. ........ a 424 408 432 115 56 2818 2849 j|ThoyFaiis:;':: " a tm 1873-1946* 1939-1947 1899-1947 1939rl947 1871-1945 1939-1947 1864-1939* 1939-1947 1935-1939* 1935-1939* ...............g TM 1900-1944 111..... 1899-1947 1938-1947 chicagogj I 1872-1947 :Up to 1946 Mdicate data not yet completed. \\ j =! i ?' j !: J) t1 1 !i i. j ! r ! Ii ' i II ` I` I: I ' 'I i ! `.vl 1 Table 1. WWliNnTter Climatic Conditions Col.'2 1 Col. 3 ' Station1* ' EleVA * ' FT iu. ... Chicago...................A . Ind... : Springfield............. Springfield............. A I Evansville.............. | Fort Wayne............C Helmer....................A 615 594 660 603 464 885 970 Indianapolis...........A Terre Haute........... C Terre Haute........... A Charles City.......... C Davenport.............C Des Moines............C Des Moines............A Dubuque............... C Keokuk...................C Sioux City...............C Sioux City............. A Concordia...............C Dodge City.-.......... C Dodge City.............A Topeka....................C Topeka....................A Wichita................... C Wichita................... A Ky. Louisville...............C Louisville................A New Orleans'....... C New Orleans........ A Shreveport............A Maine Eastport.................. C Portland -...............C Portland.................. A Baltimore................ C Baltimore............. A Mass.. Boston..................... C Boston..................... A Nantucket.............. C Nantucket.............. A Mich.. Alpena..................... Detroit.....................C 1000 1873-1933 Detroit....................A 632 1935-1939* Escanaba................. C 645 1878-1945* Grand Rapids........C 706 1891-1946* Lansing....................C 861 1910-1947 Lansing....................A 863 1940-1947 Marquette............... C 721 1874-1947 Sault St. Marie--C 724c 1888-1942* Duluth.....................C 1133 1874-1947 Duluth.................. A 1413 1941-1947 Minneapolis............ C 945 1890-1947 Minneapolis............ A 873 1938-1947 St. Paul...................C 951 1871-1933 St. Paul............... -A 708 1937-1947 Miss... Meridian..................C Meridian-............. A 410 ' 1889-1947 298 1939-1947 Vicksburg............... C 316 1874-1947 Vicksburg................A 266 - 1941-1947 Columbia................ C 739 1889-1947 j Columbia.......... - A 787 193&-1947 Kansas City........... C 741c 1889-1940 Kansas City............A 780 1935-1939* St. Louis................. C 646 1871-1947 St. Louis................. A 597 1930-1947 Springfield.............. A 1270 1935-1939* Mont... Billings.................... A 3584 1935-1939* Butter........`............ C 5700c 1894-1931 Butte........................A 5538 1931-1947 Havre.......................C 2498 1880-1947 Helena..................... C 4175c 1880-1940* Kalispell..................C 3004 1897-1947 Miles City...............C 2400 1892-1942* Miles City............... A 2629 c 1935-1939* Neb.... Lincoln.................... C 1189 1887-1947 iiill..:. ,.i Heating Load 243 CCL. 1 Col. 2 State Station1* Col.. 3 Col. 4 Elb- vation Period or Record*1 Col. 55' Col. 5 - p. ON Record^1 Aveb AGE . An nual Min Teme e *F Col. 7 Avg. WinTemp F Col. 8 Col. 9 Col. 10 Col. 11 Desic N Design Dry Bulb Temp Wind Vel. i T DryBulb Temp. Avo. Wind. Vel. - Temp. b IN COMMON Dec. Jan. Basis \ Use1 Feb.J F Mph F Mph Neb. N. H. N. J.. Lincoln............ ....A 1185 North Platte.. ...c 2815 North Platte.. Omaha . ...A ...c 2788 1219 Omaha ......... Valentine........ ...c 1009 2627 Elko................. 5079 Las Veraa ...A 1882 Reno................ 4588 Reno................ 4417 Wiunemucca... ...C 4293 Concord........... 343 . .A 359 Atlantic City... ...C 45 Camden............. ...A 20 1933-1947 1874-1947 1935-1939' 1873-1935 1935-1947 1889-1947 1935-1939 1937-1947 1905-1942 1940-1947 1871-1947 1871-1941 1941-1947 1874-1947 1935-1939* -26 -35 -32 -21 -38 -19 -16 -36 -35 -37 15 Sandy Hook.. . ...C 19 N. M... Trenton............. Albuqueraue... ...C 144 5022 Albuquerque^.. ...A 5319 7120 Rodeo................ ...A 4116 Roswell............. 3643 1931-1947 1914-1938* 1866-1946 1931-1933 1933-1947 1940-1947 1935-1939* 1905-1947 -14 ^11 -14 5 -6 -25 N. Y... Tucumeari........ ...A Albany.............. ..c 4054 114 1935-1939* 1874-1947 Albany.......................A 280 1938-1947 Binghamtoa............ C 915 1891-1946 Binghamton..............A 836 1942-1947 Buffalo.................. ,, .C 693c 1873-1945* Buffalo.............. i.. .A 726 1935-1939* Canton.................... .C 458 1889-1947 N.C. Elmira......................... A Ithaca........................... C New York..................C Oswego.........................C Rochester. ~ 948 888 425 363 Rochester. A 560 Syracuse.. 465 Syracuse......................... 404 Asheville.................... C 2280 Charlotte.................... C 809 Charlotte......... ..A 757 Greensboro... .J 896 Raleigh..........................c... 405 1935-1939* 1879-1937 1871-1947 1871-1943 18/2-1947 1935-1939* 1928-1940 1940-1947 1902-1947 1878-1947 1939-1947 1928-1947 1944-1947 -24 -14 -23 -22 --16 --24 --26 N. D. .........................A 446 .mlmington............... Cc Bismark.............___._.QC 78 1675 Bismarck.................... AA J655 Devils Lake... .C T481 Dickinson.. ..AA 2599 fSSii::::::::::! 900 1935-1939* 1871-1947 1875-1940 1940-1947 1904-1947 1935-1939* 1935-1939* --46 Ohio.. Okla.. Ore... Williston..................... C Akron......................''c 830 1919 Akron....................... . ."Aa 104 Cincinnati___ 772 Cincinnati..................A ..cCleveland.............." .C Cleveland................. [a Columbus................. .CC Columbus........... A Dayton............... 488 669 813 812 820 1086 Payton........................ a 1002 oanduskv n Toledo......... p Toledo..................... a Ardmore.. a .cOklahoma City . '. '/.C 608 668 626 762 1264 Oklahoma City Luisa............ Waynoka........... . .A a A 1311 686 Arlington.................. > t&:: 1529 881 3501 1935-1939* 1879-1947 1887-1931* 1935-1939* 1870-1947 1931-1947 1871-1946* 1930-1946* 1878-1946* 1939-1947 1883-1943 1940-1947 1878-1946* 1871-1947 1940-1947 1935-1939* 1890-1947 1939-1947 1932-1947 1935-1939* 1935-1939* 1889-1947 -50 -20 -17 -14 --17 --5 -20 -- 15 --28 -11 -16 -16 -13 -- 17 -10 -5 -25 Eugene Euaene 3374 366 368 cl 1428 1939-1947 1890-1942* 1942-1947 1911-1929 -19 -4 9 -10 -17 -14 -22 16 -10 -15 6 35.6 35.4 36.4 33.6 53.8 41.7 38.0 33.2 42.3 2 -19 -11 -11 -4 -26 -10 -3 -9 -4 6 12 13 18 -31 -33 41.2 42.0 44.3 51.4 49.1 35.2 34.7 34.8 29.5 34.9 41.1 34.4 35.1 34.8 46.1 50.6 46.4 50.0 54.6 25.3 22.9 21.7 25.6 24.5 37.3 43.0 -2 37.2 40.4 -3 38.2 40.4 38.0 -5 37.2 35.7 2 47.9 49.0 -17 35.2 33.8 45.9 45.4 44.7 -2 12.7 -9 10.7 -8 ; 11.5 . -4 23 0 7 4.0 5.3 3.6 -20 --30 -25 , 7.9 9.7 -5 --15 8.1 6.2 12 9.5 10 11.6 0 16 7.1 -6 4.6 25 8.4 16.1 10.9 0 7.3 -10 13 9.2 7.1 -10 10.5 0 9.6 -10 3 5 4 -1 22 17 .20 -24 -20 -25 -30 9 7 6 4 . 14.0 8.0 11.9 8.9 7.5 7.8 8,5 7.1 12.4 10.9 11.9 10.6 8.0 13.8 10.5 -5 17.1 ' -25 , 10.5 -15 -10 -5 11.3 16.8 12.1 -10 9.5 ' 10 7.3 10 15 -30 9.4 9.1 -30 1 . -25 -35 -5 8.6 0 01 -10 1 o .1 12.1 18 9.7 14 14.7 13 11.3 10 11.3 7 7.8 3 6.4 23 5.3 0 -10 1 1 01 0 -5 5 15 54 t 244 Cgl. 1 State' CHAPTER 12 . 1954 Guide Table 1. Climatic .CoNpmoss*---(Continued)' Col. 31 Col. 4 Col. 5 Record43 Col. 7 Col. 8. [Design Col*. 9' Col. 10 Design Avg. Win D ^ter B *Temp. . . Dry- i Wind. Bulb |VEL. ATI Temp. . esign onTAC Temp.13 97*% asis Mfb DryBtjlb -Temp. . IN Common! Use1 ' F Avo. Wind Vel. Did. Jan.. Feb.-1 Medford...................A 1343 Portland..................Cl Portland.................. A Roseburg................. C( 25 523 Curwensville..........A 2210 Erie...........................Cl 771 Erie.,.........................a! 736 1929-1947 1874-1947 1940-1947 1877-1947 1943-1947 1873-1946 1935-1939* Harrisburg..............C] 335* 1888-1938* Pa. Harrisburg..............A! Philadelphia...........CI 339 200 Philadelphia.......A 18 Pittsburgh........... .C, 929 Pittsburgh.............. AI 1284 1935-1939* 1871-1947 1940-1947 1875-1947 1935-1947 Heading................... C Scranton..................C) 311 877 1913-1947 1901-1947 Sunbury..................A 448 Block Island.......... C 46 Providence............. C1 77 1935-1939* 1881-1947 1904-1947 Charleston.............. Cl 59 1871-1947 Charleston.............. Aj 51 1940-1947 Columbia................ C! 401 1887-1947 S. D.. Columbia................A 227 Greenville...............C1 1006 Huron...................... C 1342 Huron...................... A 1287 Rapid City............. C 3309 Rapid City............. A 3220 Chattanooga...........Cl 952 Chattanooga........... A 675 Knoxville................ Cl 1024 1939-1947 ,Up to 1946 1881-1938 1938-1947 1887-1947 1939-1947 1879-1947 1940-1947 1871-1942 Knoxville................ AI 1007 1942-1947. Memphis................. C| 348 1872-1941 Memphis................. A 267 1941-1947 Texas. Nashville................. C 714 Nashville.................A 610 Abilene.....................C 1748 Abilene.................... AI 1756 Amarillo.......... ... .C 3686 Amarillo:.................A 3595 Austin...................... C 625 Austin.......... ...........A 625 Brownsville.......C[ 140 Brownsville.............A Corpus Christi... . C| 25 21 1871-1947 1939-3947 1885-1944 1940-1947 1892-1941 1941-1947 1897-1942 1942-1947 1922-1943 1943-1947 1887-1942* Corpus Christi... A, 45 Dallas....................... C 732 Dallas.......................A Del Rio....................C 520 1020 El Paso.....................C' 3792 El Paso.................... A 3956 Fort Worth..............C| 708 1943-1946* I 1913-1940 ! 1940-1947 1905-1947 1880-1942 1939-1947 1898-1039* Fort Worth............. A 728 Galveston................C) 128 1940-1947 1871-1947 Galveston............... A1 1939-1947 Houston...................C Houston...................A Palestine................. C Port Arthur............C Port Arthur.......A1 San Antonio.......Cl 198 73 555 64 21 770 1888-1947 1932-1947 1881-1947 1917-1947 1944-1947 1885-1941 San Antonio........... AI 800 1942-1947 13 tab Waco.........................A i 513 Wink.........................A 2811 Milford..................... A Modena.................... C, 5095 5472 Salt Lake City... Cl 4346 1931-1947 1935-1939* 1935-1939* 1901-1947 1874-1947 Vt. Va. Sait Lake City... A Burlington.............. C 4254 409 Burlington.............. AI 335 Cape Henry............C Lynchburg..............C 24 644 Lynchburg............. A 951 Norfolk.................... C 91 1928-1947 1884-1943 1943-1944 1874-1947 1874-1944 1944-1947 1871-1947 Richmond............... C Richmond............... A Roanoke.................. A Elleosburg --A 180 172 1194 1731 1897-1947 1929-1947 1935-1939* 1935-1939* 46.1 44.3 46.7 33.7 37.3 39.9 40.1 37.5 57.4 55.0 54.4 49.2 28.2 33.4 50.3 47.8 47.9 46.8 61.1 50.0 48.5 7.6 20.6 12.1 10.5 ' 8-0 60.6 53.5 61.0 60.1 57.1 61.2 60.6 36.3 40.0 38.3 31.5 49.2 46.8 49.3 47.0 36.2 .33 9.2 32 7.6 26 11.6 23 8.5 -2 7.7 7 7.4 15 7.1 21 8.2 1 3.8 8.3 Heating Load Table 1. Winteb Climatic Conditions*--(Concluded) 245 COL. 1 Stats Col. 2 Station1* Col. 3 Col. 4 EleTION Period of Record FT Col. 5 Low est Temp. ON Rec ord F Col. 6 Col. 7 Col. 8 Col. 9 Col. 10 Col. 11 Aver age An nual. Min. Temp. op ... Design Design Avg. Win-- ter TEMP.f Dby-Bulb Temp. onTAC 971% Wind DbyBni.n. Design Temp1* Temp. , ' IN . Common Basis* Use* * *F . F a Mph F Avg. Wind. vbl. Dec. Jan.. Feb.3 Mph Wash.. North Head........... C 199 1884-1947 Seattle ...............C 104 '1890-1947 Seattle.. ............... A 47 1928-1947 Spokane...'............ C 2030 1881-1941 Spokane.................A 1974 1641-1947 .. Tacoma................... C 279 1897-1947 Tatoosh Is.............. C 110 1883-1947 Yakima...................C 1160 1938-1946 Yakima...................A 1066 - 1644-1947 W. Va.. Elkins......................C 1969 .1898-1944 Parkersburg___'... C 685 ` 1888-1947 Wise... Green Bay......... 1C 598 1886-1947 725 1872^1947 La Crosse........ ;. ..A 677 1943-1947 Madison........... :.. .C 1008 1858-1947 Madison...................A 884 1935-1939d Milwaukee.............. C '744 1870-1947 Milwaukee.: A '707., 1927-1047 Wyo... Cheyenne................C 6144 1873-1935 Cheyenne................A 6161 1935-1947 Lander......... ..C 5448 1891-1946 lender...................:A 5568 1946-1947 Rock Springs......... A 6746 1932-1942 n 3 3 -30 -7 7 7 -24 -4 -28 -27 -36 -43 -28 -29 24 20 -5 -8 -1 -18 -21 -25 -29 -38 -34 -40 -14 -33 --12 -18 .--12 46.4 46.3 45.1 37.7 44.9 45.4 39.8 39.4 42.9 29.8 31.7 30.5 31.4 33.4 29.0 33.6 30.0 30.1 24 6.3 4 5.1 -17 -8 ' -6 --3 6.9 9.1 11.9 11.1 --7 9.1 20 15 -15 15 15 ' --5 -10 -10 -20 -25 -15 -15 -18 16.1 6.8 6.2 8.0 18.9 4.1 6.2 7.2 10.5 9.3 12.1 13.3 3.9 Alta.. Edmonton..... 2219 Up to 1943 -57 B. C... Vancouver............. ... 22 ' Up to 1943 2 Victoria...-.............. ; . 228 Up to 1943 -2 Han... Winnipeg........ ... 786 Up to 1943 -54 Fredericton.... - ... . 164 Up to 1943 i -35 Yarmouth.''.............. 136 . --12 Ont.... London..................... 612- Up to 1943 -27 Ottawa........................ 294 Up to 1943 -35 Port Arthur............... 644 Up to 1943 -40 Toronto...................... 379 Up to 1943 -26 Charlottetown.......... 186 TJp to 1943 -27 Montreal.................... "187 Up to 1941 --29 Saak... Quebec........................ Prince Albert.'.......... Dawson...................... St. Johns.- . 296 1414 1062428 Up to 1943 Up to 1943 Up to 1943 -34 -70 -68 -21 ------------------------------ ------------ . -41 13 19 -38 -25 -14 -24 -29 -11 -13 -18 -23 -47 -54 -5 22.8 42.6 44.0 17.2 27.5 34.8 32.6 26.4 22.0 32.7 29.4 27.9 24.5 16.0 .1.9 31.5 -40 10 5 -35 --20 -5 -20 -30 -10 -10 -15 -20 -45 -45 -10. 7.5 4.5 12.6 10.1 9.1 10.3 8.4 - 8.013.6 9.8 11.3 13.3 5.1 3.7 12 * United States Data compiled from U. S. Weather Bureau Records for years indicated, and Canadian uatatrom Meteorological Service-of Canada oorrected to 1946. . .. . ' f_n 2. The stations followed by letter A are airport stations, all others are city office stations and are followed by letter C. ' . * ,. . ft-. 9^ 3 The elevations marked c are ground elevations of the station. All other elevations given are the tuaielevations of the thermometer bulb above mean sea level. ' Col PM* Tta periods of record indicated apply only to the lowest temperature ever recorded shown in *w i 1'*Qd generally extend fromasummer month of the first year indicated through the spring months of year indicated. The periods marked by * terminated in December of,the year indicated. . Average of readings of one lowest temperature obtained for each year. . for period October to April, inclusive. tbia8/irrf^UTk no^'e<^ that Col. 8 applies only to airports, as these data for city stations are not available at excepH^f o7iz 6 temperature shown is the minimum hourly.outdoor temperature which has been equalled or Pointed ,'jlp,?enfc0f the total hours in December, January and February for the period of record. It is to rural "*atm most cases the airport stations are outside of the city and.these data would apply primarily than * 'odicates the maximum wind velocity which occurred at temperatures the same as, and lower ;* lDe temperatures shown in Col. 8. for thRvn^ records design temperatures in use by A S.H.VJ5. Members as reported by Chapter Secretaries tion stations. Where these were not available the design temperatures from an ACRMA publica- *"0 various other sources have been inserted. ' :' t^lIt>'Sef^bi^948^OC^^es ^dicated in Col. 11 were furnished by the U. S. Weather Bureau and corrected prePard by A.S.H.V.E. and U. S. Weather Bureau for annual weather data of city of Detroit " 88 "esin temperature based on Dec. to March, inclusive. ^foputed for Reading by Karl Shelley and O. F. Smith. Heating Load 247 average wind velocity from December through February is 15 mph or higher in only 7 of the cities listed and Column 9 shows that-a wind velocity, of 15 mph did not occur in any city listed for temperatures; equal to or lower than those shown in Column 8 for the years 1935^ 1939. Conse quently, it will often be desirable to modify the U; values in Tables 6 to 9 and 15 to 19 of Chapter 9 to correspond to lower wind velocities. , Correc tion factors for different wind velocities can be found in Table 21 of Chapter 9. : : ) Column 6 in Table 1 lists the average annual minimum' temperature' which is the average of readings of the one lowest temperature occurring for each year the weather station has been in existence. . A comparison of the temperatures listed in Columns 6, 8, and 10 of Table 1 offers some guid ance in selecting a suitable outdoor design temperature for particular cities. For the 63 cities in the United States having temperatures listed in all three columns the average annual minimums in Column 6 average 2.3 deg warmer than the design temperature in common use listed in Column 10 whereas the design temperatures in Column 8 average 11.0 deg warmer than those in Column 10, There are variations of 6 deg or more in either direction from these average differences, however, for a few cities in this group. ------,- ' Designers are cautioned against attempting to compensate for internal vagrant heat sources in a structure, the heat generated by electrical equip ment, the approximations that may exist in heat transmission factors and infiltration rates, and the safety factors used in selecting heating plant capacity by adjusting the design temperature difference between indoors and outdoors. These factors should be accounted for by more careful analysis of their existence and magnitude in computing the heating load that must be carried by the heating plant itself. - tween the O F and 10 F isotherms would normally have a design temperature^ of 5 F although sharp changes in elevation must be taken into consideration^ in mountainous areas. This map will be of considerable value in selecting- design temperatures for cities and towns not listed in Table 1. !llp The design temperatures in Column 10 of Table 1 are often used witfe^g design wind velocity of 15 mph. However, Column 11 shows that ttjijjg INSIDE TEMPERATURES The inside air temperature which 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. Inside air temperatures usually-specified, vary in accordance with the intended use of the building. Table 2 presents values which'conform to good practice. The proper dry-bulb temperature to be maintained depends upon the relative humidity and air motion, as explained 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 effective temperature for sedentary persons, as determined at the A.S.H.V.E. Research Laboratory, is 67-68 ET. As explained in Chapter 6 for so-called still air conditions, a relative umidity of approximately 50 percent is required to produce an effective jnperature of 68 ET when the dry-bulb temperature is 72.5 F. However, h^611. yhere provision is made for artificial humidification, the relative umidity is seldom maintained higher than 40 percent during the ex theme y ?ld weather, and where no provision is made for humidification, th6 cC d've humidity may be 20 percent or less. Consequently, in using relat' UreS *n Table 2, consideration should be given to the actual cat'6 humidity to be maintained, if provision is to be made for humidifi- 10n- If no humidification is to be provided, the higher temperatures 248 CHAPTER 12 1954 Guide may. not even produce comfort on cold days; if humidity is to be main tained at 50 percent, the lower temperatures will apply. ; In rooms having-large glass areas, when sun is not shining, or in rooms with walls having'a1 high transmission coefficient,, the lowered surface tem perature will cause a feeling of coolness even though the air temperature in the room is at or 'above the 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. Table 2. Winter Inside Dry-Bulb Temperatures Usually Specified Typb of Building Deo F Ttpe of Building Deg F Schools-- .. - Class rooms......................... : Assembly rooms....................... Gymnasiums............................. Toilets and baths..................... - Wardrobe and locker rooms.. Kitchens............................... . .Dining and lunch rooms....... , Playrooms.................................. Natatoriums.............................. Hospitals-- Private rooms......... ;* Private rooms (surgical). Operating rooms............... Kitchens and laundries.. Toilets.......................... Bathrooms.................' 70-72 68-72 55-65 70 65-68 66 65-70 60-65 75 Theaters-- Seating space.. Lounge rooms.. Toilets............. Hotels-- Bedrooms and baths..................... Dining rooms................................. Kitchens and laundries................ Ballrooms......................................... Toilets and service rooms............ 70-72 70-60 70-95 68 66 68 70-80 Homes................................................................. Stobes............................................. Public buildings.................;................. Wabm aib baths....................................... Steam baths....................................... Factories and machine.shops.. Foundries and boiler shops... Paint Shops............................................. 68-72 .68-72 70 70 66 65-68 68 70-72 65-68 68-72 120 no 60-65 50-60 * The most comfortable dry-bulb temperature to be maintained depends on the relative humidity and . air motion. These three factors considered together constitute what is termed the effective temperature. (See "t Chapter 6.) When relative humidity is not controlled separately, optimum dry-bulb temperature for comfort will be slightly higher than shown in Table 2. '/ The inside temperatures specified in Table 2 may be used for panel heated spaces as well as for spaces heated by warm air, radiators or con--' vectors. It is true that warm panel surfaces tend to produce a comfortable " environment at a lower room air temperature than when warm panels are . not present, but field experience in the United States has indicated that ' actual reductions in air temperature are slight in operation. Temperature at Proper Level. In making the actual heat loss compmV tations, however, for the various rooms in a building it is often necessary;, to modify the temperatures given in Table 2 so that the air temperatureat the proper level will be. used. By air temperature ai the proper level is'.; meant, in the case of walls, the air temperature at the mean height be?" tween 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 stratification of air resulting fmmV the tendency of the warmer or.less dense air to rise. An allowance 1~. -- , fact should be made in calculating ceiling heat losses, particularly in thel 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 inside# outside temperature differential The type of heating system is paT Heating Load 249 uuuiany important, as the temperature gradient from floor to breathing- level to ceiling may depend to a large extent on whether direct radiation, unit heaters or warm air 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 hav ing ceiling heights under 10 ft, the comparatively small temperature differential between the breathing level and ceiling generally may be Table 3. Approximate Temperature Differentials Between Breathing Level and Ceiling, Applicable to Certain Types of Heating Systems* Ceiling Height (Ft) Breathing Level Temperature (5 ft Above Floor) 70 10 n 12 13 14 15 16 17 18 19 20 3.0 3.6 4.2 4.8 5.4 6.0 3.3 3.5 3.9 4.2 4.6 6.2 4.9 5.6 5.9 6:5 6.3 ~.7.0 3.6 4.3 5.0 5.8 6.5 7.2 3.7 4.4 5.2 5.9 6.7 7.4 3.8 4.0 5.3 6.1 6.8 7.6 6.1 6.2 6.3 6.4 6.5 6.6 6.7 7.0 7.1 7.2 7.3 7.4 7.5 7.3 7.4 7.6 7.6 7.7 7.5 7.6 7.7 7.8 7.9 7.7 7.8 7.9 8.0 8.1 3.9 3.7 65..25 7.0 7.8 7.9 8.0 8.2 8.3 4.0 4.8 5.6 6.4 7.2 8.0 8.1 8.2 8.3 8.4 8.5 4.3 5.1 6.0 6.8 7.7 8.5 8.6 8.7 8.9 9.0 4.5 5,4 6.3 87..12 9.0 9.1 9.2 9.3 9.4 9.6 35 40 45 50 7.0 7.5 8.0 8.5 9.0 9.5 7.5 8.0 8.5 9.0 9.5 10.0 8.0 8.5 9.0 9.5 10.0 10.5 8.2 8.7 9.2 9.7 10.2 10.7 8.4 8.9 9.4 9.9 10.4 10.9 8.6 9.0 9.1 9.3 9.5 9.6 10.1 10.6 9.8 10.3 10.8 10.0 10.5 11.0 ___1_1_.1_____1_1_.3_____1_1_.5____ 9.6 10.0 10.6 11.0 11.5 .:I12.0 10.0 10.5 11.0 11.5 12.0 12.5 * The figures in this table are based on an increase of 1 percent per foot of height above the breathing level (5 ft) up to 15 ft and J4o of one degree for each foot above 5 ft. This table is generally applicable to forced air types of hating systems. For direct radiation or gravityvf&rm air, increase values 50 percent to 100 percent. neglected without serious error. For higher ceilings, an allowance of approximately 1 percent per foot of height above the breathing level may be made for ceiling heights up to 15 ft and approximately jV of 1 deg per foot of height above this level. The values in Table 3 are calculated on this basis. For direct radiation and gravity warm air systems, the allow ance should be increased from 50 percent to 100 percent over those given in Table 3. These rules should, however, be used with considerable dis cretion, and 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,3-4-* 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 ceiling temperatures. Tests at the University of. Wisconsin7 indicated a somewhat smaller differential 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 floor differential may jdsabe neglected, as the two are somewhat compensating, especially where fioth-floor and ceiling losses are calculated for the same space. In other cases> the 10 ft temperature differentials in Table 3 may be used in arriving I CHAPTER 12 at the floor heat loss, these differentials to be subtracted from tije breathing level temperature. ' ATTIC TEMPERATURES Frequently, it is necessary to estimate the attic temperature, and in such cases Equation 1 can be used for this purpose: . 1 M! AJJcTj 4- lM,U, +_A,,[/, + AgUt) u = Actfe 4" Ar(/r 4~ AwUw 4~ AgUg . (1) where 4 = attic temperature, Fahrenheit degrees. h = inside temperature near top floor ceiling, Fahrenheit degrees. 4 = outside temperature, Fahrenheit degrees. Ac -- area of ceiling, square feet. A, = area of roof,.square feet. A* = area of net vertical attic wall surface, square feet. ft, Ag = area of attic glass, square feet. Uc = coefficient of transmission of ceiling, based on surface conductance of 2.20 (upper surface, see Chapter 9). 2.20 = reciprocal of one-half the airspace resistance. Ui = coefficient of transmission of roof, based on surface conductance of 2.20 (lower surface, see Chapter 9). Uw -- coefficient of transmission of vertical wall surface. Ug = coefficient of transmission of glass. Example 1. '' Calculate the temperature in an unheated attic, assuming the follow' 5/i ing conditions: 4 = 70; 4 - 10; Ac = 1000; A, = 1200; Aw = 100; At = 10; V, = S 0.50; Ug = 0.40; Vw = 0.30; Ug = 1.13. g Solution: Substituting these values in Equation 1: 7ifS'- (1000 X 0.40 X 70) 4- 10[(1200 X 0.50) + (100 X 0.30) + (10 X 1.13)] . 4 = (1000 X 0.40) + (1200 X 0.50) + (100 X 0.30) + (10 X 1.13) *; 4 = ^^ = 33.1F. 1041 . .p Equation 1 neglects the effect of any interchange of air such as would-Jy take place through attic vents or louvers intended to preclude attic con-fesa densation. However, according to tests,8 such venting of attics by means of small louvers or other small openings does not appreciably reduce the<J| attic temperature and may be neglected without serious error. jl Neither does this equation take into consideration such factors as heat:|t exchange between chimney and attic or solar radiation to and from the' roof. Because of these latter effects, actual attic temperatures are fre-'J~; quently higher than the calculated values using Equation 1. The atticfp temperature may be calculated in the usual manner by means of Equation- ,:; 1, allowing the full value of the roof. The error resulting from this assumi>g|J: tion will generally be considerably less than if the roof were neglected (as lCfi sometimes the practice) and the attic temperature assumed to be the samesv as the outside temperature. When relatively large louvers are installed;^ as is customary in the southern states, the attic temperature is often as-'|-j sumed as the average between inside and outside. For a shorter, approximate method of calculating heat Josses throughg -% Heating Load 251 attics, the combined ceiling and roof coefficient may be used, as described in Chapter 9. TEMPERATURES IN UNHEATED SPACES The heat loss from heated rooms into unheated rooms or spaces must be based on the estimated or assumed temperature in such unheated spaces. This temperature will lie in the range between the inside and outside temperatures, depending on the relative areas of the surfaces ad jacent to the heated room and those exposed to the outside. If the re spective surface areas adjacent to the heated room and exposed to the outside 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 inside and outside design temperatures. If, however, the surface areas and coefficients are unequal, the tempera ture in the unheated space should be estimated by means of Equation 2. 4 = t(AJJi 4- AtUg 4- AsUs -4- etc.) 4- t0(Aat7a 4- AO't, 4- Act/c 4- etc.) ` AiUi 4- AiUi 4 4- etc. 4- .4aU,, 4 AbUb 4- A0f/C 4- etc. (2) where 4 -= temperature in unheated space, Fahrenheit degrees, t = inside design temperature of heated room, Fahrenheit degrees. 4 = outside design temperature, Fahrenheit degrees. At, As, As, etc. = areas of surface of unheated space adjacent to heated space, square feet. A,, Ab, Ac, etc. = areas of surface of unheated space exposed to outside, square feet. Vi, Us, Us, etc. = coefficients of transmission of surfaces of Au As, Aa, etc. Ug, Ut,, Ue, etc. = coefficients of transmission of surfaces A.,, Ab, Ac, etc. Example 8: Calculate the temperature in an unheated space adjacent to a heated room having surface areas (A >, A,, and Aa) in contact therewith of 100, 120, and 140 sq ft and coefficients (Us, Us, and Us) of0.15,0.20, and0.25, respectively. The surface areaB of the unheated space exposed to the outside (A and Ab) are respectively 100 and 140 sq ft, and the corresponding coefficients are 0.10 and 0.30. The sixth surface is on the ground and is neglected in this example. Assume f = 70 and 4 = -- 10. Solution: Substituting in Equation 2: . ( = 70f(100 X 0.15) 4- (120 X 0.20) 4- (140 X 0-25)1 4- -lQfdOO X 0.10) 4- (140 X 0.30)1 " (100 X 0.15) 4- (120 X 0.20) 4- (140 X 0.25) 4- (100 X 0.10) 4- (140 X 0.30) , _ 1?60 _ " 126 37 P' The temperatures in unheated spaces having large glass areas and having two or more surfaces exposed to the outside (such as sleeping porches and sun parlors), generally are assumed to be the same as outside. GROUND TEMPERATURES Ground temperatures to be assumed for estimating basement heat losses usually will differ in the case of basement walls and floors, the tem peratures under the floors generally being higher than those adjacent to walls. Factors affecting these temperatures will be discussed. Temperatures Under Basement Floors The temperature of the ground under basement floors9 is affected by osat sources within the basement and is not influenced by atmospheric CHAPTER 12 conditions. In computing losses through basement floors, the ground tem peratures may be assumed to be the same as water temperatures at depths of 30 to 60 ft given in Fig. 3, Chapter 35. Test observations indicate that heat losses through basement floors frequently are over-estimated.10 Temperatures Adjacent to Basement Walls . 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 result in a higher ground temperature near the surface. Therefore, in localities where the ground is covered with a heavy blanket of snow throughout the Table 4. Below Gbade Heat Losses fob Basement Walls and Floors Gboond Watbb Temperature* Basement Floor Lossb Btu/Sq Ft Below Grape Wall Lossb Biu/Sq Ft 40 50 60 * See Fig. 3, Chapter 35. b Based on basement temperature of 70 F and U of 0,10. . winter, the ground temperatures near the surface will be higher than whenj| little or no snow is present. Complete data on ground temperatures adjacent to buildings are not|| available, but since the recommended transmission coefficient for base-ii? ment walls in contact with the soil is only 0.10, any reasonable, assumed^ ground temperature will not materially affect the calculated heat. loss. Js: BASEMENT TEMPERATURES AND HEAT LOSS 4) ,' %) 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 cck'efficients (see Chapter 9) and the outside air and, ground temperatures^ Heat loss through windows and walls above grade should be based on outjrjg side temperatures and the proper air-to-air coefficients. Heat loss through,* basement walls below grade should be based on the floor and wall coeffi-;, cients for surfaces in contact with the soil, and on the proper grounds! temperature. ..^1 The heat loss values for below grade basement walls and floors given >ii Table 4 are sufficiently precise for general practice. 'J.:' If a basement is completely below grade and is not heated, the tenir; i perature in the basement normally will range between that in the rooms.;, above and the ground temperature. Basement windows will,, of courser- lower the basement temperature when it is cold outside, and heat given ojTj by the heating plant will increase the basement temperature. In any case>|; the exact basement temperature is indeterminate if the basement is heated. In general, it is found that the transient heat from the heating^ plant warms the air near the basement ceiling sufficiently to make it u|( ' -iiS Heating Load 253 necessary to make 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. It is necessary, therefore, to evaluate the. conditions and to select an appropriate temperature by judgment. HEAT LOSSES FROM FLOOR SLABS Two types of concrete floors used in basementless houses are (a) the unheated floor, relying for warmth on heat delivered 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 loss, economically considered, is of minor importance since is 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 connection, it should be remembered that a well insulated floor does not assure comfort if down-drafts 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 heat ing system that delivers enough heat near the floor to counteract the .down drafts of the exterior walls and the heat transmission through the floor. The results of some experiments10,11 with type (a) unheated floor slabs indicate that the heat loss from a concrete slab floor on grade is more nearly proportional to the perimeter than to the area of the floor, and that the heat loto can be estimated by means of the equation: where Hr = FP (t - ,,) (3) Hr = heat loss of the floor, BtU per hour. P = perimeter or exposed edge of the floor, linear feet. F = heat loss coefficient, Btu per (hour) (linear foot of exposed.edge) (degree dif ference in temperature between the inside air and the outside air). (F ranges between 0B1 for a floor with no edge insulation to 0.55 for a floor with edge in sulation). 1 = inside air temperature, Fahrenheit. to = outside air temperature, Fahrenheit. In most instances the values given in Table 5 for edge loss are of sufficient precision for use.12 The insulation shown extending under the floor hori zontally for 2 ft can also be, located along the foundation wall with equal effectiveness if the insulation extends 24 in. 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 unheated concrete slab which is insulated at the edge ^th 2 in. of insulation extending horizontally for a distance of 2 ft from the edge, Mio the house is located in an area with an outside design temperature of --15 F. From Table 5 the heat loss per foot of exposed edge is 45 Btu per hr. length of exposed edge is 12 ft + 15 ft = 27 ft, and the total edge loss 27 x 45 = 1215 Btu per hr . Floors of type (b) containing heating pipes or ducts, are now in common 254 CHAPTER 12 1954 Guide !&' use. The heat loss downward into the ground and outward through the edges of the floor slab is called the reverse loss. , 1 The results13 of an investigation in which a warm-air perimeter duct was embedded in four types of concrete floor slab and foundation constructions has verified the indication that Equation 3 can be used to calculate the reverse loss when warm-air perimeter heating ducts are used. To make the results of this application more usable, values corresponding to those shown in Table 5 for unheated' floors are given in Table 6 for concrete floors with a warm-air perimeter duct. The desirability of edge insulation is apparent. One inch of waterresistant material is the minimum thickness of edge insulation that should be used, but a 2-in. thickness is recommended.12-14 The values of edge loss in Table 6 indicate that the reverse heat loss of heated slabs is likely to be about 20 percent of the total heat loss of many types of present day Table 5. Heat Loss of Concrete Floors at or Near Grade Level per Foot op Exposed Edge Heating Load ,, ______ _ kji oiiiuauussion, air to air, Btu per (hour) (square foot) (Fahr enheit degree temperature difference) (Chapter 9). I ~ inside temperature near surface involved (this may not necessarily be the so-called breathing line temperature), Fahrenheit degrees. l0 ~ outside temperature, or temperature of adjacent unheated space or of the ground, Fahrenheit degrees. Example 4: Calculate the transmission loss through an 8 in. brick wall having an area of 150 sq ft, if the inside temperature t is 70 F and the outside temperature t0 is -- 10 F. _. .. ' Solution: The coefficient of transmission (U) of a plain 8 in. brick wall is 0.50 (Chapter 9, Table 8). The area (A) is 150 sq ft. Substituting in Equation 4: Ht -- 150 X 0.50.X [70 -- (--10)1 = 6000 Btu per hour. Table 6. Floor Heat Loss to be Used When Warm-Air Perimeter Heating Ducts Are Embedded in Slab* Bin per (hour) (linear foot of heated edge) . Outdoob Design Tempbratube, F Edge Insulation Lin. Vebtical Extendino Dowr 18 IN. Below Floob Subpace 1*in. L-Type Extend- 2-in. L-Type Extend- ing Deep at Least 12 in and 12 in. Undeb I Down at Least 12 in. and 12 in. Undeb houses, and may exceed 20 per cent if only one inch of insulation 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 waterproof membrane should be in stalled over the gravel fill. Obviously, it is important that such floors be laid several inches above grade, and that effective subsoil drainage be pro vided to avoid slabs soaked by rain or melting snow, and consequent excessive heat loss. TRANSMISSION HEAT LOSS The basic formula for the loss of heat by transmission through surface is given in Equation 4: Ht = AV (t - O `-IitV-?s*rrvr-* where Ht = heat loss transmitted through the wall, roof, ceiling, floor, or glass, per hour. A -- area of wall, glass, roof, ceiling, floor, or other exposed surface, square .1_j * Factors include loss downward through inner area of slab. Transmission Lpss Through Ceilings and Roofs The transmission heat loss through top floor ceilings, attics, and roofs may be estimated by either of two methods: . 1. By substituting in Equation 4 the ceiling area A, the inside-outside tempera ture difference (t -- t>) and the proper value of U: a. Flat roofs. Select the coefficient of transmission of the ceiling and roof from Tables 15 or 16, Chapter 9, or use appropriate coefficients in Equation 1 if side walls extend appreciably above the ceiling of the floor below. b. Pitched roofs. Select the combined roof and ceiling coefficient from Table 18, 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 estimating the attic temperature (based on the inside and outside design temperatures) by means of Equation 1, and substituting for< in Equation 4, the value of th thus obtained, together with the ceiling area A and the ceiling coefficient 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 paragraph la. INFILTRATION HEAT LOSS The infiltration heat loss includes (1) the sensible heat loss or . the heat required to warm the outside air entering by infiltration, and (2) the latent neat loss or the heat equivalent of any moisture which must be added. 256 CHAPTER 12 Sensible Heat-Loss The formula for the heat required to warm the outside air which enters jS| O r 65 room by infiltration to the temperature of the room, is given in Equation x .' m VTl H. = 0.240 Qd (i - Q (5) It. where ff. = heat required to raise temperature of air leaking into building from t,, to t, =| Btu per hour. 0.240 = specific heat of air. ,v. : Q - volume of outside air entering building, cubic feet per hour (see Chapter. 11). *' d = density of air at temperature to, pounds per cubic foot. i` #f'4* It is sufficiently accurate to use d = 0.075 in which case Equation 5jj reduces to * H, = 0.018 Q (t - U) .(5a)?* ift- j The volume Q of outside air entering per hour depends on the wind]|J velocity and direction, the width of crack or size of openings, the type ofJ5 openings and other factors, as explained in Chapter 11. Where the crack#? method is used for estimating leakage, it is more convenient to express7^ the air leakage heat loss in terms of the crack length: ^ ' Hil H, = B Hi - 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. >5. : )t L = length of window or door crack to be taken into consideration, feet. Example 6: What is the infiltration heat loss per hour through the crack of a 3 x : 5 ft average, double-hung, non-weatherstripped, wood window, based on a wind#; velocity of 15 mph? Assume inside and outside temperatures to be 70 F and rero,;/ respectively. Solution: According to Table 2, Chapter 11, the air leakage through a window of#, this type (based on W in. crack and in. clearance) is 39 cu ft per (ft of crack),# (hour). Therefore, B = 39 X 0.018 = 0.70. The length of crack L is (2 X 5) f.m (3 X 3), or 19 ft; t -- 70 and /,, = 0. Substituting in Equation 5b, .'<( H, = 0.70 X 19 X (70 - 0) = 931 Btu per hour. ' Crack Length to be Used for Computations t-(S 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 than half of the total length of crack in the - outside walls of the room. For a building having no partitions, air enter#; ing through the cracks on the windward side must leave through the#cracks bn the leeward side. Therefore, take one-half the total crack for# computing each side and end of the building. In a room with one expos^v, wall, take all the crack; with two exposed walls, take the wall having tlie.*,. Heating Load 257 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; infiltrationJosses of the-various rooms.. However, this is not necessarily- accurate:as at any given time infiltration will take place only on-the: windward, side or sides and not on the leeward side. Therefore, for determining .-the total heat requirements 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 Computations Since a certain amount of judgment is i required regarding quality of construction, weather conditions; use of room; and other factors in esti mating 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 calculatingJnfiltration- 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, ? .......... , .. where : Hi = Qd (IV, - IK) A,' ' (6) fit -- heat required to increase moisture content of air leaking into building from m,, to m,, Btu per hour. '' . Q - volume of outside air entering building, cubic feet per hour, d = density of air at temperature'tj, pounds per cubic foot. = vapor density of inside air, pounds per pound of dry air. d# - vapor density of outside air, pounds per pound of dry air. = latent heat of vapor at m,, Btu per pound. If the latent heat of vapor h/,, is assumed to be 1060 Btu per lb, Equa- tmn 6 reduces to: . '' //, = 79.5 Q (Wi.- Wo) (6a) ari?(}ua*'*ons 5a, 5b and 6a may also' lx: used, for determining the sensible . u latent heat gains due to infiltration in cooling load computations. SELECTION OF WIND VELOCITIES ^The ef[ect of wind on. the heating requirements of any building should -Riven consideration for two reasons: ; . ^ movement increases the heat transmission of walls, glass, and roof, . poo^ walls to a much greater extent than good walls. ;h 258 CHAPTER 12 1954 Guide Heating Load 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 11). , ? Theoretically, as a basis for design, the most unfavorable combination of temperature and wind velocity should be chosen. It is entirely possible that a building might require more heat on a windy day with a moderately low outside temperature, than on a quiet day with a much lower outside temperature. However, the combination of wind and temperature, which is the worst, would differ with different buildings, because wind velocity has a greater effect on buildings which have relatively high infiltration : , ; * losses. It would be possible to compute the, heating load fpr a building for several different combinations of temperature and wind velocity which records show to have occurred, and to select the worst combination, but * designers generally do not feel that such a degree of refinement is justified. ^ Therefore, since Table 1 lists the maximum wind velocity occurring A during the coldest 2\% of the winter hours for each locality, this value should be the basis for estimating infiltration losses. ; When using the air j: change method it will not be necessary to consider the wind velocities. V Designers employing the crack method generally use values corresponding ./k; to a 15-mile wind. The effect of the wind velocity on the transmission,/ coefficient can be evaluated from Table 21 of Chapter 9. Exposure Factors Many designers use empirical exposure factors to increase the calculated) heat loss of rooms or spaces on the side or sides of the building exposed tof| the prevailing winds. However, the use of exposure factors is unnecea^J sary when the Guide method of calculating heat losses is used. Therefore, <r. jf exposure factors may be regarded as factors of safely for the rooms or spaces ) exposed to the prevailing winds, to allow for additional capacity for these;') rooms or spaces, or to balance the radiation, particularly in the case offJ multi-story buildings. Tall buildings may have severe infiltration hea^S losses, induced by their stack effect (see Chapter 11), which will require;) | special consideration. Although the exposure allowance frequently is as)/ sumed to be 15 percent, the actual allowance to be made, if any, must tof;T a large extent be a matter of experience and judgment of the designer,-)'8 since there are at present no authentic test data available from which rules/ | could be developed for the many conditions encountered in practice. ,A;:j AUXILIARY HEAT SOURCES J Electric Motors and Machinery 259 Motors and the machinery which they drive, if both are located in. the room, convert all of the electrical energy supplied into heat. This heat is retained in the room if the. product manufactured is. not removed until its temperature is the same as, the room temperature. ] ;> ` ;; If' power is transmitted tofthe machinery from themutside, then only the heat equivalent of the brake horsepower supplied is used. In somemills this is the chief source of heating, and it is frequently sufficient to overheat the building even in zero weather;, thus requiring pooling by ventilation the year 'round. Table 7 shows the heat Output equivalent Tabi.e 7. Heat Equivalents op Various Sources* Machinery (Motor in room) = Motor Hp/efficiency x 2544 Btu/hr. Machinery (Motor outside room) = Motor Hp x 2544 . Btu/hr. Electric Lights = Kilowatts x 3413 Btu/hr. Gas (Producer = 150) (Manufactured = 535) (Natural = 1000) Btu/cu ft. * Additional values are given in Chapter IS, Table 26, - of various sources of heat in a factory. For information concerning the heat supplied by persons, refer to data given in Chapter 6, and also Table 25, Chapter 13. For appliances see Table 26, Chapter 13. INTERMITTENTLY HEATED BUILDINGS In the case of intermittently heated buildings additional heat is required for raising the temperature of the air, the building materials and the ma terial contents of the building to the specified inside temperature. The rate at which this additional heat must be supplied depends upon the heat capacity of the structure and its material contents, and upon the time in which these are to be heated.16 . . . This additional heat may be computed and allowed for as conditions re quire, but inasmuch as the heating system proportioned 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 either be continuously heated or have more time allowed for heating up during the few minimum temperature days, no allowance usually is made, except in the size of boilers or furnaces. For churches, auditoriums and other intermittently heated buildings, additional capacity should be provided. - The heat supplied by persons, lights, motors and machinery always) should be ascertained in the case of theaters, assembly halls, and industrials plants, but allowances for such heat sources must be made only after careful/ consideration of all local conditions. In many cases, these heat sources) should not affect.the size of the heating plant at all, although they may hav& a marked effect on the operation and control of the system. In generate^ where audiences are present, the heating system must have sufficien/ j capacity to bring the building to the stipulated inside temperature befpre& the audience arrives. In industrial plants, quite a different conditio)/ exists, and heat sources, if always available during occupancy, may jpg substituted for a portion of the heating installation. In no case should tn, actual heating installation (exclusive of heat sources) be reduced b that required to maintain at' least 40 F in the building. RESIDENCE HEAT LOSS PROBLEMS The following Examples 6 and 7 will illustrate the procedure for ealcuriting the heat Toss of a residence, uninsulated and insulated, in accordance 'vith the recommendations given in this chapter. v\J\Xam^e `. Calculate the heat loss of the residence shown in Fig. 2 located in the w-!!lty ot Chicago. From Table ), design outdoor conditions are --10 F and 12mph unh ve,ocity. Inside temperature from Table 2 is assumed to be 70 F. The attic is bas<^ate<*' J^saume ground temperature to be 50 F (see Fig. 3, Chapter 35) under losse garage floors and 32 Fadjoining basement walls. Estimate infiltration eider h- ^ air change method. No wall, ceiling or roof insulation is to be con ed in this problem, but all first and second floor windows, except in the garage, - Beating Load 261 Table 8. Heat Loss Calculation Sheet fob Uninsulated Residence A B C D E . r . ` o' . Space and Closet Bedroom B Part or Stbdctcbk or , Net Abba ' Infiltration Air Changes OB Aib Volume COEFFI* WENT Temp. Dipt.* Heat Loss" : (Btu per. ( - hour) ` ' , Totals' hour) Walls Glass Ceiling Infiltration ()* 238 sq It 40 sq ft 2$2 sq ft 1510 cfbb 0.28 0.45 0.69 0.018* SO 80 , 39.3d 80 . 5330 . 1440 . . 6910 ' 2180. 15,860 Wails Glass Ceiling Infiltration (H)K ' 156 sq ft - 40 sq ft 170 sq .ft 1020 cthb 0.28 0.45 0.69 0.018* 80 80 . 39.8 80 3490.. 1440 , 4660' . 1470 11.060 Bedroom C and Closet Walls - Glass Ceiling Infiltration ($tf)*: 114 sq ft 27 8Q ft 129 sq ft 874cfhb 0.28 0.45 0.69 0.018* 80' 80 .. 39.3d 80 2560 970 . 3540 1260 8,330 Bedroom D and Closet Walls ' Glass Ceiling ' Floor over garage Infiltration (H)1 ' 118 sq ft 20 sq ft ' 110 SQ ft' 110 SQ ft 680cfhb 0.28 0.45 0.69 0.25 0.018* 80 2650 . 80 . 720 39.3d 3020 - 35* 960* - 80 - . 950 8,300 Bathroom 1 Walls ' Glass Ceiling ''* -- Infiltration (l)1 30 sq ft 0.28 80 14 sq ft 0.45 80 . . 55 sq ft 0.69 39.3d 440cfhb 0.018* 80 Bathroom 2 Living Boom Dining Hoorn Kitchen and Entrance lo Oarage Wue and Vest) hula ________ Entrance Hall -- Oarage Walla Glass Ceiling Floor over garage Infiltration (1)* 79 sq ft 9 sq ft 35 sq ft - 35 sq ft 280cfhb 0.26 0.45 0.69 0.25 0.018* 80 80 . 39.3d 35* 80 Walls Walls (adjoining garage) Glass Floor ." Infiltration UH/ 267 sq ft 94 sq ft 50 sq ft ` 294 sq ft 3745cfhb 0.28, 0.39* 0.45 0.018" 80 35* SO 80 Walls Glass (doors) Glass (windows) Floor . Infiltration (1V$)* 166 sq ft - 35 sq ft 20 sq ft . 168 sq.ft 2140 rfhb 0.28 0.85 0.45 0.018* 80 80 80 80 Walls Wails (adjoining garage) Glass Door Floor . Infiltration (l)$y ' 96 sq ft 51 sq ft 18 sq ft 17 sq ft . 125 sq-ft 1595cfhb 0.28, 0.39* 0.45 0.51 80 35* 80 35 0.018* .80 Walls Walls (adjoining garage) Gian Door Floor Infiltration 0H)k 85 sq ft 9 sq ft 19 sq ft 30 sq.ft 383clnb 0.28. 0.391 0.45 0.51 0.018* 80 35* 80 80 80 Walls Door Ceiling1 Infiltration^)1 Walla Glass Doors Infiltration (1M)" Floor Gain adjoining rooms ' 39 sq ft 21 SQ ft 87 sq .ft 1110cfhb 167 sq ft 53 sq ft 44i ft 2360 cfhb 29 ft* 0.28 80 0.38 * 80 . 0.69 39.3d 0.018* 80 0.28 1.13 0.51 0.018* 0.81 45* 45 45 45 45 Walb Glass Floor % ______ Infiltration (1)D 220 sq ft 8 sq ft 287 sq ft 2010 cfhb 0.10 1.13 0.10 0.018 38 80 20 80 670 500 '1510 630 ; * 1640 320 960 310* 400 5980 1280* 1800 5400 3720 2380 720 3080 2150 700* 650 300 2300 1840 1160* 320 780 550 870 640 2390 1600 2110 2700 1010 1910 1060 -4410* 840 720 570 2890 3,310 3,630 '14,460 9.900 6,100 4.650 5,500 4,380 5,020 -_ TOTAL 100,500 I; 'y Heating Load 263 Notes for Table 8. * The inside-outside temperature difference is 70-- (--10) or80F except where otherwise noted. b Volume of infiltration, cfb * (no. air. changes) x (floor or ceiling area) x (ceiling height). c From Equation 5a. , .; d The ceiling heat losses are calculated by estimating the attic temperature and then calculating the loss tw.pheir.--norcdatuFetTgurrhhormeemt*h-oiohsneE.t--iqhlrcinuseJOg.aliliintFnhiToggenahauunetossdl.aoiiann.srtggsoteiocttshhmatee,ertmepperrmpcooaeppplrceeeau-rrrt*alu--attteertueemmrdeippsbieeseyrrsaa7ettt0iuumsFrrteeiam.tddeaiidTfftffieehnfrrregeeonntmtheccemeeE..apqteutTTriacahhttiitiusseormneuupnndrehhtifteeoftetaa*ruttbeee*endd<c3.aae-0tt.--tt2isiiccFt.h--iiK.sswepn.nnhnooe7ttn0v-v--teeh3nne0tt.ii2ollaauottteersddi3d9dde.8uutrrediinenmmggg-.-'`.:ij-.=f For the insulated residence, attic temperature becomes 4.6 F and temperature difference 70--4.6 = 65.4 deg. e* TCeomefpfiecireantut froerinwagallragdejoainsisnugmgeadratogebcea3lc5uFla.ted on basis of metal lath an d plaster oh both sides of studs (U = 0.39). , - Jj 6bOEnxepohsaeldf oofnvtawluoesfidroems, wTeaabtlbee4r,stCrihpappedtewr 1in1d, ofowrssotoffrsmetwbiyndfiorew-sploarcew.eaUthseers\Ytrti.pping. S. 1 Window on one side weatherstripped but double-doors are hard to close tightly. Hence, conservatively valu1eAossf u1mHi.ng kit.chen vent, doo'r to vestibule usually open, allow full tabl.e value oi 1)5. k One-half value in Table 4, Chapter-H, increased to 1H by nearby outside door in vestibule. ' ' 1 Full value in Table 4, Chapter 11, to allow for frequent opening of outside door. " Two sides exposed, huge doors but huge volume. Use-value IH as given in Table 4, Chapter 11. D Two small unweatherstripped windows in protected location, but fireplace, indicate 1* change. pQ HNegaltelcost sheesaftrolomssthtoesbearsoeommesnitn, taos gloasrsaegsefaroremhebaotilgear,inpsipfoinr gg,areatgce.,. will probably keep basement near;^- if not above, 70 F. . - . . ^ 1 Upstairs ball ceiling figures with downstairs- Heat should be provided downstairs for both. ^ * Linear feet of exposed edge. . ^5*; Table 9. Summary op Heat Losses of Uninsulated Residence (Btu Per HovrfS^ ------R---o--o-m---O--R---S-p--a-c--e--------------- ----------'------~-------"-- ----'- :--------:-----i---G--e--a-r--s--a--n--d^--|--.--1-K--M--r-------]----T--o--t-a--u--| Bedroom A Bedroom B Bedroom C Bedroom D Bathroom 1 Bathroom 2 Living Room Dining Room Kitchen Lavette Entrance Hall Garage Recreation Design Totals Operating Totals Perceennttaaggeess' 8 Wall heat loss of 2110 Btuh minus wall heat gains of 1280, 700 and 1160 Btuh 310 Btuh. c Based on >5 oomputed infiltration. d Based on operating totals. Heat Rains of 9 Table 10. Summary of Heat Losses of Insulated Residence (Btu Per Room OR Space | Wards | | Floor j I ,ICKKT?ILT-_ I Tor TRiTlOS Bedroom A Bedroom B Bedroom C Bedroom D Bathroom 1 Bathroom 2 Living Room Dining Room Kitchen Lavette Entrance Hall Garage Recreation 2480 1620 1190 1230 310 760 3370 1730 1320 1390 410 --47Q8 840 2460 1660 1260 1060 570 2.540 1440 1440 070 720 500 320 .1800 3100 1915000 640 3710 7*:o Design Totals Operating Totals' 2.540 4.6 Perc8ecenWntataaggleleshs*de* at loss of 980 j Btuh zv.i minus j wall heat gains , of 590, 320 and 540 Btuh. Btuh. c Based on H computed infiltration. d Based on operating totals. 24.620 12.310 22.1 rM 2-fel are to have storm sash. The building is constructed as follows (heat transmission coefficients U are parentheses): , - .1 Walls: Brick veneer, building paper, wood sheathing, studding, metal lath and plaster (0.^). Walls of dormer over garage, same except wood siding in place of brick veneer (0.26). . Attic Walls: Brick veneer,, building paper, wood sheathing on studding (0.42). Basement Walk: 10 in. concrete (0.10). Eoo/: Asphalt shingles on wood sheathing on. rafters (0.53). . Ceiling (Secondfloor): Metal lath and plaster (0.69). . Windows:double-hung wood windows averaging 70 percent glass (0.45; from Chapter 9, Table 19, Section D, the U value for wood windows with storm sash is 0.53 x application factor; by interpolation this factor is 0.85). Steel casement sash in garage and basement (1.13;from Chapter 9, Table 19,- U is 1.13 for all glass and the application factor is 1.00). French doors in dining room 50 percent glass, no storm doors (0.85; from Chapter 9, Table 19, U is 1.13 for all glass; by interpolation the application factor is 0.75). . Floor (Bedroom D): Maple finish flooring on yellow pine sub-flooring; metal lath and plaster ceiling below (0.25). ` 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 8, and a summary of the results in Table 9. The values in column F of Table 8 were obtained by multi plying together the figures in columns C, D, and E. The heat losses are calculated to the nearest 10 Btu. See reference notes for Table 7 for further explanation of data. Attention is calledToThe summary of heat losses (Table 9) for the uninsulated resi dence. As storm windows are used in this instance the aloes and door transmission heat losses of 19.8 percent are relatively small. The infiltration losses of 14.0 per cent are also comparatively small because the storm windows are equivalent to weatherstripping. In this problem, the wall, ceiling and floor transmission losses comprise 66.2 percent of the total. Example 7: Calculate the heat loss of residence shown in Fig. 2 based on the same conditions as in Example 6 but having construction improved or insulated to obtain coefficients as follows: Walk, 0.13; Walk of Dormer over Garage, 0.12; Attic Walls, 0.28; Walk Adjoining Garage, 0.18; Basement Walls (Recreation Room), 0.10. . Poof, 0.53. Ceiling (Second Floor), 0.15. Windows (Same as in Example 6). Floor (Bedroom D), 0.18. Solution: The procedure for calculating the heat losses is similar to that for Example 6. A summary of the results is given in Table 10. REFERENCES \ ACRMA Application Engineering Standards for Air Conditioning for Comfort, (1947), Air Conditioning n RefrigrmtinQ Machinery Association, Inc., pages 4 to 7. . !An Analysis of Winter Temperatures for One Hundred and Twenty Cities, by Clark M. Humphreys Institute of Technology Bulletin 1939). - (s `Investigation of Oil-Fired Forced Air Furnace Systems in the Research Residence, by A- P. Kratz and AOnto {University oj Illinois Engineering Experiment Station Bulletin No. 318). h .* Performance of a Hot-Water Heating System in the I=B=R Research Home at the University of IUi- **> by A. P. Kratz, W. S. Harris, M. K. Fahnestock, and R. J. Martin (University of Illinois Engineering azPenmcnt Station Bulletin No. 349). * /,* A Study of fodiant Baseboard Heating in the I=B=R Research Home, by A. P. Kratz and W. S. Harris mrsity of Illinois Engineering Experiment Station Bulletin No. 358). ' o/ ;ir*ertor.?Pance of a One-Pipe Steam System in the I=B=R Research Home, by W. S. Harris (University nou Engineering Experiment Station Bulletin No. 383). 185) ID' Research Report No. 1011--Tests of Three Heating Systems in an Industrial Type of G* 1*. Larson, D. W. Nelson, and John James {A.S.H.V.E. Transactions, Vol. 41, 1935, p. Moisture Control and Their Application to Building Construction, by F. B. Rowley, A. B. a e**" G- E. Lund (University of Minnesota, Engineering Experiment Station Bulletin No. 17). HoiioL, 369). tD' Research Report No. 1213--Heat Loss Through Basement Walls and Floors, by F. C. I* Taimuty, Cyl Gutberlet and C. J. Brown (A.S.H.V.E. Transactions, Vol. 48, i942, p. Measurements of Heat Losses from Slab Floor, by R. S. Dill, W. C. Robinson and H. E. Robinson I* l 'fii 11 I5 r i :i S .w :! I 202 {V. S. Department of Commerce, National,Bureau of Standards, Building Materials and Structures Report BMS11 T10e3in).peratur'e and Heat `Loss C.h..a..r.a...c..t.e..r.i.s..ticsof Concr'ete Fl`oors Laid on ti.e Ground, by H. D. Bareithe.r, A. N- Flemming and B.'E. Alberts (University of Illinois, Small.Homes Council Technical-Report). ' .^Concrete.Floors for Basementless Houses (University'of 'Illinois, Small Homes Council Circular No. F . ). - ` . :4 3 " Waarrmmre-fcAei.rFPloeorrims etoterr Heating, --,, Part . III--Heat Losses and S. Konzo. (A.S.H.V.E.'Joubnal'Seoton, Heatin9, f'ProipminFgloanodr SAlairb'C,h.obvnyJd.i.i.t;iRon. JiJnaagmm, iiFeeessoobnn. ,,19RR5_2.. ,Wp_. . RBoooobbs 128). 14 Worro-Atr Perimeter Heating--Manual 4, National Warm Air Heating and Air Conditioning-Association. . ^ Heat Requirement Tables .for. Intermittently. Heated Buildings, {Engineering Sxperimcnt Station < Bulletin No. 60, A andM. College of College'Station, Texas) contains a set of tables applicable to either . intermittent heating or cooling. Further'information may be found in a paper, A Method of Compiling Tables for Intermittent Heating, by Elmer G. Smith (A.S.H.y.E. Jopbnap Section, Heating, Piping and Air Conditioning, June 1942, p. 386). ' ' -' ' '' r , . '` ` ' CHAPTER 13 COOLING LOAD Cooling Load Calculations; Design Conditions; Instantaneous Heat Load; Solar Ra diation; Periodic Heat Flow; Tables for Calculating Solar Heat Gain Through Walls, Roofs and Glass; Instantaneous Heat Gain vs. Cooling Loads; Load from Interior Partitions, Ceiling arid Floors; Load from Outside Air; Ventilation ind Infiltration; Effect of Outside Air on Load; Heat Sources Within Conditioned Space; Moisture Transfer Heat Load; Miscellaneous Heat Loads; Apparatus Dew-Point and Required Air Quantity Through Conditioning Equip ment; Minimum Entering Air Temperature; Ex- 1 ample Cooling Load Calculation AJK"t, ?^ ::%%k 4&. it*U*..; % 'ft '"W. "^fte THE variables affecting cooling-load calculations are numerous, often difficult to define precisely, and always intricately inter-related. Most of the components of the cooling load vary in magnitude over a wide range during a 24-hour period, and as the cyclic changes' in load com ponents are not usually in phase with each other, careful analysis is re quired to establish the resultant maximum cooling load for a building or zone. A. zoned system must often handle peak loads in different zones at different hours. Economic considerations must be of particular influence in the selection of equipment for cooling season operation in comfort air conditioning, and this fact, coupled with present inadequacies in available data and knowl edge of the air-conditioning art, places a premium on the experienced judg ment essential to successful design or practice. Variations in the weather, building occupancy, and other factors affecting load, necessitate carefully coordinated controls to regulate simultaneously the components and the equipment in order to maintain the desired room conditions. The calculation procedures presented in this chapter deal with the vari ous instantaneous rates of heat gain, both sensible and latent, in a condi tioned space. There may be an appreciable difference between the net instantaneous rate of heat gain and the total cooling load :at any instant. This difference is caused by the storage and subsequent release of heat by the structure and its contents. This thermal-storage effect may be quite im portant in determining an economical cooling equipment capacity. The lack of any-adequate means of treating this storage quantitatively in its entirety for a complete structure, must, be recognized in judging the pro cedures aod data presented for calculating individual components of the net rate of instantaneous heat gain. Solar heating calculations involve the same principles as cooling load Emulations. Many of the data on solar radiation given in this chapter En be used in calculations for solar heating. COOLING LOAD CALCULATIONS Summer cooling load calculations, whether for industrial or comfort Pplications, require consideration of the following factors: Design Conditibns: (1) indoor conditions; (2) outdoor conditions; (3) venti- curate. .. Instantaneous Heat Load, Sensible and Latent: (1) load from solar radiation, 265 CHAPTER 13 sky radiation and from outdoor-indoor temperature differential for glass areas and| exterior, walls and roofs, modified by periodic heat flow or lag factors depending on the type of structure; (2) load due to heat gain through interior partitions, ceilings)^ and floors; (3) load due to ventilation, either natural or mechanical; (4) load duefr to heat sources within the conditioned space such as people, lights, power equipment,3ft and appliances; (5) load due to moisture transfer through permeable building'? materials; (6) miscellaneous heat sources. i ft C. Determination of Air Quantity and Apparatus Dew-Point. . These factors will be discussed in turn. The material presented leads'to an illustrative procedure for a cooling-load calculation, and a numerical!? example is given to demonstrate the calculations involved. J DESIGN CONDITIONS Indoor Conditions . Indoor air conditions for human health and comfort have been and con-;) tinue to be the subject of much discussion and research. .! The effective temperature index, explained in Chapter 6 is probably; the best available source of design criteria for comfort air conditioning; systems for buildings or enclosures in which the air and inside surface! Table 1. Typical Commercial Design Room Conditions fob Summer Average i Peak Load in Comport Air Conditioning* Type of Installation Dry-Bulb Temp Deluxe Application------------Normal Application-----------15 to 40 min Occupancy---- 78 80 82 Wet-Bulb Temp* 65 67 68 Relative Humidity Per Cent 50 51 49 Grains Per Lb* 72.7 78.5 80.0 Effective^ Temp* , 72.2 -A 74.0 75.3 * Values in Table 1 are tor peait 10ac contusions. a 8ca*ca* ______ f_______ _ mately 76 F and 50 percent relative humidity at other than peak load. k Psychroroetric data for standard barometric pressure.. * Fig. 10, Chapter 6, air movement 15 to 25 /pro. ' ' ` temperatures remain substantially equal; a condition that can safely be). . assumed for most ordinary comfort air conditioning installations. Other)' sources of design specifications are to be found in the requirements of codes'. and ordinances, and in the varied long-term experiences of manufacturers)! contractors, and engineering specialists. '$>) Past experience, cumulative over many years, indicates that indoor dev; sign conditions for which summer air-conditioning equipment is select^ should not exceed a temperature of 80 P or a relative humidity of 50 per cent for the average job in the United States. If these conditions exceeded, complaints of discomfort may be expected, especially with continu-.; ous occupancy. For very, brief occupancy only, a slightly higher peak; load design temperature may be employed. In regard to the lower lim'li of humidity, complaints are not encountered for store installations opi ated down to 35 percent relative humidity or, for office jobs, somewhat; lower. These observations apply to normal commercial practice in thi?\ country only; for extremes, such as tropical or very hot regions, it is regard#; as more practicable to design for a peak-load outdoor-indoor temperature) difference of about 15 to 20 F. : Table 1 offers typical design conditions for average requirements countered. The deluxe figures would also apply in general for locality?? having a summer outdoor design temperature of 90 F or less; and the. 15 to Ifi min occupancy values, or even somewhat higher dry-bulb tenj Cooling Load 267 peratures, would indicate acceptable conditions for very hot localities. Table 1 is to be used until good judgment, for there is no universal rule which may be applied to indoor design conditions. Guarantees of conditions to be maintained for summer operation 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 and equipment capacity, and by the method adopted for regulating the system operation. Complete specifications of indoor design conditions would include part-load and overload operation, 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 condi tions for products in industrialair conditioning are,given in Chapter 45. The load calculations for either comfort or industrial air conditioning are usually made in accordance with a guarantee. In comfort applica tions, 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. Dur ing very hot weather, the room temperature will rise above the control point and the equipment will operate continuously. Normally, industrial jobs are operated 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 zone 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, and this should be kept in mind when calculating the convective portion of the roof heat gain. A reduction of outdoor-tomdoor air temperature differential may be assumed in such instances; radiation from the inner roof surface is not diminished. Outdoor Conditions Summer climatic conditions and suggested design wet-bulb and drybulb 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 com paratively short, and higher temperatures may be expected. In making comparisons for other localities than those shown in Table 2, due considera tion must be given to elevation. Column 6 of Table 2 indicates the design dry-bulb temperature suggested oy the A.S.H.V.E. Technical Advisory Committee on Weather Design renditions. This temperature is the maximum hourly outdoor temperaure which has been equalled or exceeded 2\ percent of the total hours of "ne. July, August and September for the period of record, in this ease .6 5-year period 1935-1939, and should not be confused with the period record given in Column 4 which applies only to highest temperature er recorded. Since all of these data (Column 4) are based on airport Th 4they are 11k necessarily applicable to cities. Ch "a*'a ven 'n Columns 7 and 8 were obtained from local A.S.H.V.E. apter Secretaries, and represent the design temperatures in local use. of !<UC^ *nfrmation was not available, it was taken from a publication e a.C.fl.M.A.1 and from various other sources. 268 CHAPTER 13 . " -- - 1954 Guide ?V - -. n The Technical Advisory Committee on Weather Design Conditions has suggested that wet-bulb design temperature be taken/as that wet-bulb ; temperature which has been equalled or exceeded in 5 percent of the hours -- during months of the period of record. While not available for the 1953 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 particu larly 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 tabulation: ' East Sea Shore..............12 to 18 East of Mississippi River........................19 to 24 . Gulf Sea Shore.............. 12 to 18 Mississippi River to Rocky Mountains__ 24 to 33 Great Lakes Shore___ 18 to 21 Rocky Mountain Area.............................. 33 to 42 West Sea Shore.............15 to 20 West Coastal States.................................. 20 to 36 Ventilation Rate 1! . . '1 'll. The introduction of outside air is necessary for the ventilation of condi1 tioned spaces. Chapter 6 suggests minimum outdoor-air requirements fof representative applications; but it is to be emphasized that minimum re,1; quirements are not necessarily adequate requirements for all psychological | attitudes and physiological responses. Where maximum economy in space | arid load are essential, as in submarines or other restricted spaces, as little | as 1 cfm of outside air per person has been found to be sufficient .provided- 1 that satisfactory ventilation is simultaneously obtained by an adequate 1 decontamination of recirculated air.2 /, 1 Local codes and ordinances frequently specify ventilation requirements. I for public places and for industrial installations. For operating rooms,-; minimum requirements for safe practice are given in National Board of Fin Underwriters' pamphlet.5 This pamphlet does not require 100 percent outside air in operating rooms, although 100 percent outside air is normally used and recommended. .-d: Recommended and minimum ventilation rates for the most common applications are summarized in Table 3. For further general applications, a basis of estimating the cfm per person may be taken as: `' 1. People not smoking.................................... 74 Recommended 2. People smoking.......................................... 40 Recommended . -iifc 5 Minimi#*. | 25 Minimvff g The cooling load due to the introduction of outside air for ventilation is | determined once the indoor and outdoor design conditions are fixed. Csf. dilations will be discussed subsequently. .' .Vi -'tit Cooling Load 269 <?,,,, " 2` Sdmmer C^tic CoNhmoNs* SumstedDeszgn Wet-Bulb'and Dry-Bulb Temperatures Statb Col. 2 Station1* Col. 4 Period Record11 Ala.. Axis. Ark, Calif., Anninston........ CO Birmingham___CO Birmingham.... AP Mobile...... v........ CO Mobile................AP Montgomery___ CO Montgomery___ AP Flagstaff........ CO Kingman........... AP TMoenix............ :CO Phoenix.............. AP Tucson...... ,..,.Ap Winslow.............. CO Winslow............ AP Yuma................. CO Fort Smith........ CO Fort Smith........ AP Little Rock........ CO Little Rock........AP Bakersfield........ AP Burbank......._ .AP Lteggefce............ Ap` 1893-1947 1893-1945 1939-1947 1872-1947 1940-1947 '1872-1947 1938-1944d 1899-1947 1935-1939 1895-1947 1932-1947 1935-1939 Up to 1946 1937-1947 1875-1946 1882-1945 1945-1947 1879-I942d 1942-1947 1937-1946 1931-1947d Colo.. Conn.. D.C.. FU... Eureka............. CO Fresno.................CO Fresno................ Ap Los Angeles....... CO Oakland............. AP Red Bluff.. CO Red Bluff...........AP Jedding............. AP bacramento........CO Sacramento..AP San Diego.......... CO San Diego..........AP gan Francisco...CO ^n Jose........CO Williams___ AP Dearer.............. CO Denver...............AP Durango............ CO Orand Junction.CO Juebo................CO ............... ap gartford............ CO gartford..^....... AP New Haven...... CO New Haven...... AP Washington....... CO Washington.... AP Apalachicola.... CO Jacksonville ... CO Jacksonville... AP gey West.......... CO gey West.......... AP 90 34 164 100 124 6398 6379 6668 4587c 4770 4810 229 20 180 17 128 20 23 104 29 23 48 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 1871-1947 W34-1947 Up to 1946 Up to 1946 1889-1938 1939-1947 , m5-1940d 1940-1947 1872-1947 1943-1947 1871-1947 1935-1939 1922-1947 1871-1947 1935-1947 1871-1947 1939-1947 253 1896-1947 Ga.. Pensacola........ CO Pensacola...........AP iJ^pa............... CO ............AP Titusville...........AP Atlanta___ AP 4uusta...........;.C0 Augusta..............AP wMaaccoonn..................................ACPO 13 67 113 111 12 52 1020 196 424 408 1940-1947 1879-1947 1943-1947 1890-1940 1941-I946d 1935-1939 1935-1939 1871-1946 1939-1947 1899-1947 Idaho! gavannah.......... CO fK;........-co 432 115 56 2818 1939-1947 1871-1945d. 1939-1947 1864-1939 Burley. ...........ap Idaho Falls.::; AP 2849 4150 1939-1947 1935-1939 Lewiston.......... CO Pocatello.......... CO 4744 763 1935-1939 1900-1944d ni... 4522 1899-1947 4467 1938-1947 319 1872-1947 2Sr~S\ 601 Up to 1946 615 J935-1939 594 1932-1947 I _Col. 6 Col. 7 Design Design Dry-Bui b Temp. T.A.C. o 24 J_ % Dry-Bul b Temp, ui CoMMpr, Basis* F Use* F Con. 8 I Col. 9' Design Wet-Bdia Average JTemp, ua bOMMEB Commoi , Wind Use* Velocity* F Mph 95 78 94 95 . .78 5.4 h92 95 ' 80 8.6 95 '78 99 io7 102 *95 97 104 94 104 103 'so .I ioi '79 m '93 95 '88 '84 '92 90 105 105 100 iio 95 05 105 90 105 90 85 100 ... 166 85 85 91 95 95 95 95 93 95 95 95 95 98 65 76- 72 70 78 76 70 6.0 6.1 6.2 65 74 70 65 70 72 *68 65 70 64 65 65 65 75 '75 78 80 78 78 7.9 7.9 10.7 6.9 7.4 ^9 8.4 '96 93 93 95 94 88 92 92 94 1 ... 95 76 98 76 95 '78 95 78 95 65 95 95 98 1 95 96 I 65 65 "78 75 "75 7.9 270 CHAPTER 13 1954 Guide Col. 1 State Table 2. Summer Climatic Conditions* (Continued) Suggested Design Wet-Bulb and Dry-Bulb Temperatures Col. 2 Station1* Col. 3 Eleva tion* Col. 7 I Col. i Design Design Dry-Bulb | Wet-Bulb Temp, in Common '` Use* Ft 111... Peoria.................... AP Springfield.......... CO 660 603 Springfield.......... AP 608 Ind~ Evansville...........CO Fort Wayne........ CO 464 885 Helmer--.......... AP 970 Indianapolis. CO 816 Indianapolis.... AP 800 Terre Haute------CO 1146 Terre Haute.... AP 589 Iowa... Davenport.......... CO Des Moines.........AP 648 979 Dubuque............. CO 740 Keokuk.................CO 637 Sioux City........... CO 1093c Sioux City........... AP 1098 Kans.. Concordia............CO Dodge City......... CO 1425 2515 Dodge City......... AP 2599 Topeka.................CO 991 Topeka.................AP 883 Wichita................ CO 1497 Wichita................ AP 1423 Ky- Louisville.............CO Louisville..............AP 563 544 La.. New Orleans___ CO 85 New Orleans -- AP Maine.. Shreveport......... AP Eastport.............. CO Portland..............CO 117090 185 Portland.............. AP 65 Md....... Baltimore........... CO Baltimore..............AP 114 43 Mass.. Boston................. CO Boston.................. Ar 356 45 Nantucket.......... CO 45 Nantucket..........AP 48 Mich.. Alpena.................. CO Detroit................. CO 1601050 Detroit................ AP 632 Lansing................CO 861 Lansing.................. Ar 863 Marquette............ CO 721 Duluth...................CO 1133 Duluth................... AP 1413 Minneapolis......... CO 945 Minneapolis......... AP 873 St. PaulT..............CO 951 1935-1939 1879-1947 1930-1947 1897-1940, 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 1874-1946 1873-1933 1934-1947 1910-1947 1940-1947 1874-1947 1874-1947 1941-1947 1890-1947 1938-1947 1871-1933 Mo.. St. Paul................. AP Meridian.......... - CO Meridian................ AP Vicksburg.............CO Vicksburg............ AP Columbia..............CO Columbia. *..........AP Kansas City.... AP St. Louis...............CO St. Louis............... AP Springfield........... AP Billings.................. AP Butte...................... AP Havre..................... CO 708 410 298 316 266 739 787 780 646 597 1270 3584 5538 2498 1937-1947 1889-1947 1939-1947 1874-1947 1941-1947 1889-1947 1939-1947 1935-1939 1871-1947 1930-1947 1935-1939 1935-1947 1931-1947 1880-1947 Helena....................CO Kalispell............... CO 4175 3004 1880-1940 1897-1947 Miles City............ AP Lincoln.................. CO Lincoln.................. AP North Platte... .CO North Platte. .. .AP 2629 1189 1185 2815 2788 1935-1939 1887-1947 1933-1947 1874-1947 1935-1939, Omaha................... CO Omaha................... AP Valentine..............CO 1219 1009 2627 1873-1935 1935-1947 1889-1947 Nev. N. H Elko........................ AP Las Vegas.............AP Reno....................... CO Reno....................... AP Winnemucca... .CO Concord................. CO Concord................ AP 5079 1882 4588 4417 4293 343 359 1935-1939 1937-1947 1905-1942 1940-1947 1871-1947 1871-1941 1941-1947 76 77 78 75 `76 '78 78 78 78 78 78 78 78 T8 75 T8 '46 78 70 73 '78 75 75 8.2 -- C7.0 * ... 'r 8.9 It 8.6 ... i ; ...' snjj. * '' li's :%. 7.2 6-9 'ti ... W 8-7 f: 7A 12.5 jg - - io'.2>3& Cooling Load 271 Table 2. Summer Climatic Conditions* . (Continued) Suggested Design Wet-Bulb and Dry-Bulb Temperatures Col. 1 State Col. 2 Station1* Ohio.. Okla.. Ore., Atlantic City.. .CO Camden................ AP Newark................. AP Trenton................. CO Albuquerque___ CO Albuquerque___ AP El Morro...............AP Rodeo.....................AP Roswell..................CO Tucuracari.......... AP Albany...................CO Albany........... .. AP Binghamton___ CO Binghamton.. .AP Buffalo................... AP Canton................ CO Elmira............ r.. .AP New York..... .CO Oswego................ CO Rochester........... CO Rochester........... AP Syracuse...........CO" Syracuse.............. AP Ashville............... CO Charlotte........... .CO Charlotte.............AP Greensboro........ AP Kaleigb................ .CO Raleigh.................AP Wilmington........ CO Bismarck.............CO Bismarck.............AP Devils Lake....... CO Dickinson........... AP Fargo..................... AP Pembina AP WiUiston...............CO Akron..................... AP Cincinnati........... CO Cincinnati........... AP Cleveland............. CO Cleveland............. AP Columbus.............CO Columbus.. AP Dayton.................. CO Dayton..................AP oandusky........ CO Toledo.................... CO loledo.................... AP Ardmore.......... AP Oklahoma City . CO Oklahoma City.AP Tulsa.................... AP Waynoka............^AP Arlington___ AP 2ajcer............ co tfaker................... AP ugene..............! CO Eugene................ AP JJ^jford.............. CO Medford. AP Portland..............CO ortland..............AP Jr^aburg............ CO ^urwensville AP fn*........................CO ft. i. S| C... fe^wg....; .ap pt!We phia co Cp*la^elphia....AP p^bm-gh.......... CO Pittsburgh.......... AP feeding............... CO . : > Pmljjktond ...CO providence..........CO Chareston...........CO Charleston... AP Col. 6 Design Drt-Bul b Temp, on TA.C. 2*? ? Basis*5 F Col. 7 ' Design Dby-Buu3 Temp, in Common Use' F Cot. 8 I Col. Q . . Design Wet-Buli Temp, in Common Use' ' Average Summer Wind.' Velocity* F Mph 95 9i 89 95 95 95 93 64 97 95 97 93 88 95 86 93 90 88 95 93 95 89 93 88 93 93 . 95 91 95 95 93 95 95 96 95 94 93 95 92 . 95 88 95 95 94 95 90 95 90 95 78 75 78 8.8 : 70 7.8 . 70 75 75 '73 . 73 . 75 73 75 - 75 - 75 . 78 78 78 78 73 70 75 73 75 78 75 76 78 7.5 12! i 8.2 12.5 . 5-6 . 6.3 8.4 9.5 5.6 ii.i 9i 99 99 100 103 95 90 *88 95 87 82 '85 . 91 88 89 95 95 ioi loi 90 90 95 90 90 93 95 95 95 95 95 95 93 95 75 75 . 77 77 66 68 70 68 66 75 78 75 75 75 75 75 78 9.8 6.5 9.7 4^9 9.5 . 9.8 272 CHAPTER 13 Table 2. Summer Climatic Conditions* (Concluded) " --j n-.._ R*,ih Tfimveraturegf S. C.. S. D.. Columbia........... CO Columbia........... AP Huron................ CO I Huron'............... AP . Rapid City...-.CO . Rapid City....... AP Chattanooga___CO I Texas-. Chattanooga___AP . Knoxville........... CO Knoxville........... AP Memphis........... -CO Memphis............ AP Nashville--...CO Nashville-..........AP Abilene............CO Abilene............ AP . Amarillo.............CO Amarillo............. AP ( Austin.................CO . Austin................ AP Brownsville........CO Brownsville.-....AP J Corpus Christi. .CQ Corpus Christi. .AP I, Dallas................. CO Dallas................ AP ' Del Rio..............CO , El Paso.............. CO i EFol PrtaWsoo..r..t.h..................ACPO I Fort Worth........ AP . Galveston...........CO Galveston.......... AP Houston.............CO Houston--j,.. .AP . Palestine............ CO Port Arthur.......CO | Port Arthur.......AP [ San Antonio___ CO > San Antonio___ AP . Waco................... AP Wink.................. AP Utah Milford...............AP Modena..-........... CO Salt Lake City.. CO Salt Lake City. AP Burlington......... CO Burlington......... AP Cape Henry.......CO Lynchburg......... CO Lynchburg........ AP Norfolk............... CO Richmond..........CO Richmond..........AP Roanoke............ AP Wash... ENlolernthsbHuerga.d............ACPO | Seattle................ CO | Seattle................ AP . Spokane............. CO Spokane.............AP Tacoma...............CO Tatooeh Island.CO , Yakima........ \. -CO Yakima..............AP | W. Va... Wise... Wyo.. Parkersburg ... -CO Green Bay.........CO La Crosse........... CO La Crosse........... AP Madison.............CO Madison............. AP Milwaukee......... CO Milwaukee......... AP Cheyenne.......... CO Cheyenne........ .AP lander................ CO Lander.*.............AP Rock Springs - .AP 1887-1947, , 1939-1947* 1881*1938 1938-1947 1888*1947 1939-1947 1879-1947 1940-1947, . I$7l-1042d | 1942-1947, I 1872-1941* 1941-1947 1871-1947 1939-1947 , 1888-1944** 1 1940-1947 1892-1941 1941-1947 1897-1942 1942-3947, , 1922-1943d 1 1943-1947 1887*1942 1943-1946 1913-1940 1940-1947 1908-1947 1887-1942 1939-1947 1898-1939 1940-1947 1871-1947 1939-1947 1888-1947 1932-1947 1881-1947 3917-1947 1944-1947, , 188S--1941d [ 1942-1947 1931-1947 1935-1939 1935-1939 1901-1947 1874-1947 1928-1947, i 1884-1943d ! 1943-1947 1874-1947 1874-1944 1944-1947 1871-1947 1897-1947 1929-1947 1938-1939 1938-1939 1884-1947 1890-1947 1928-1947, , 1881-1941 1941-1947 1897-1947 1883-1947 1928-1946 1944-1947 1888-1947 1886-1947 1872-1947 1948-1947 1858-1947 1938-1939 1870-1947 1927-1947 1873-1935 1935-1947 1891-1946 1936-194? 1932-1942 Con. 6 Coi. 7 DESIGN Dby-Bulb Design DBy-BuLB. Temp, on Temp, in TJV.C. 24% Common Basis .: Use*' F BF Col. 3 1 Cot,. 9 ^ Design Average Wet-Bulb j SUMMEB Temp, in Wind Common \-\/Et-oemt* Use1 F Mph ^ --. ' 75 ... ;S- 95 '95 1 75 )0-3 . 94 94 96 - 97 , 96 . ::: ,, 95 95 95 95 95 ioo ioo 1 '70 '75 78 '78 '74 72 .7-9 ' 5- 5.7 K H /(I 7.3 ... ii.8 V ioo 78 ioo 7.6 .3* 80 . '95 ' '80 ioo '78 : 1. ;* Cooling Load 273 NOTES FOR TABLE 2 * Data compiled from' U. S. Weather Bureau Data and various other sources. , , .. . ; b Column 2. The station designation AP or CO indicates airport or city office station, respectively. e Column 3. The elevations marked c are ground elevations of the station. All other elevations given are the actual elevations of the thermometer bulb above mean sea level, corrected to 1948. '' d The periods of record indicated apply only to the highest temperature ever recorded-rshown in Column 6, and do not necessarily include all of the summer months of the first year indicated.' The last year indi cated includes July or August, except those marked d which terminate prior to July of that year. - - - It should be noted that Column .6 applies only to airports, as these data for city stations are not avari able at this time. The temperature shown is the maximum hourly outdoor temperature which baa been equalled or exceeded 2Jpercentof the total hours of June. July, August and September for the 8-year period 1938-1939, inclusive. It is pointed out that in most cases the airport stations are outside of the city, and that these data would apply primarily to rural areas. '- ' ' J :` * Columns 7 and 8 record wet and dry-bulb temperatures in'use by A.S.H.V.E; Members as reported by Chapter Secretaries for various stations. Where such values were not available, the design temperatures published by A.C.R:M.A., or obtained from various other sources, have been inserted. ` ' c The average wind velocities Indicated in Column 9 were furnished by the U. S. Weather Bureau, cor rected to 1947. In general these velocities are averages for .the months of June through September. . h The bulletin published by A.S.H.V.E. for the annual weather data of Detroit indicates'73 F as the de sign wet-bulb temperature winch has been equalled or exceeded 8 percent of the hours for period 1935-1939. . * Blank spaces indicate data not available. ' . - ..... Table 3. Ventilation Standards Application . Smoking CFM PEB PEBSONb CPU PEB SQb Ft op Floob Recommended Minimum Minimum Deluxe.. ............................... Some........ Banking Space.................;..................... Occasional.......... Barber Shops.........................'.................. Considerable___ Beauty Parlors......................................... Occasional........ 20 30 . 10 15 10 50 40 Directors' Rooms............... :................... Extreme...... . 74 50 Drug Stores............................................ Considerable__ ive and Ten Cent Stores...................... 'None.............. None................... Garages......................:.......................... ' 10 10 ?4 10 Hospitals Operating Rooms** *............ None................. Private Rooms...................... None................. Hotel Rooms............................................ Heavy............... .30 20 30 , Residence.................................. laboratories............................................. Some................. 20 unices General Some............. ,, , Private.......................................... Considerable... Restaurant Cafeteria Considerable... Dining Room.................... Considerable... hool Rooms*1........ ' 1 heater ..................... ................. - Toileted (Exhaust)......-.......... ............. None............. Some................. 50 15 25 30 12 15 io 74 15 . 10 25 n 10 7} 20 25 , 5 : 30 74 74 5 -7* 25 10 25 . 30 10 15 25 10 12 74 10 6.33 6.25 0.05 o.io . i.`o* 2.0 0.33 0.33 2.0 , 1.25 6.25 0.25 6:6' a_j ^ahen from present-day practice or large air conditioning companies. b This is contaminant-free air ia e*ther outdoor air or recirculated air which has been appropriately purified. 0 When minimum * M& ularger of the two. d See local codes which may govern. May be governed by exhaust. pJrfy b governed by special sources of contamination or local codes. * All outside air recommended to rcome explosion hazard of anesthetics. See National Board of Fire Underwriters' pamphlet No. 56. INSTANTANEOUS HEAT LOAD The total cooling load is frequently divided for convenience into two components, sensible heal and latent heat. While this subdivision is not "Operative, past practice has found it convenient. . A gain of sensible heat is considered to occur when there is a direct addi- 274 CHAPTER 13 1954 Guide tion of heat to the enclosure by any one or all of the mechanisms of conduc tion, convection, and radiation. A gain of latent heal is considered to occur when there is an addition 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 drybulb temperature and a high humidity ratio, and the corresponding escape of room air at a lower dry-buld temperature and a lower humidity ratio, would increase both the sensible heat load and the latent heat load. . 2, . SOLAR RADIATION 4 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 J because a large part of the 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 A 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 pur- i-I poses, is confined to the radiation spectrum between 0.3 and 2.3 microns! j.'- The effects of scattering and absorption vary with the wave length, but to make an exact analysis of these phenomena is impracticable in air:<; conditioning estimates. The important principle to remember is that the ' total radiation /,, received by a surface at the earth, is the sum of In and ./ It, where :: Cooling Load 275 Fio. 1. -UTOMVEPRETRICPEANLDIWCUALLLAR ^*ALL AZIMUTH, f ^SOLA* AZIMUTH, f Definition of Solar Angles Have been proposed by Moon.4 Table 4 gives these values. They are representative of a clear summer day at sea-level elevation, and are nearly identical with values derived from suggested design sol-air temperatures for Lincoln, Nebraska.6 Values typical of a humid industrial area derived from sol-air data for New York City6 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 temperatures near the design values of 95 F and 75 F (67 F dew-point). On the other hand, values Table 4. Values of 7d0> Direct Solar Radiation Received atTvormal Incidence It,at the Earth's Surface, and Values of. Diffuse or Sky Solar Radia tion, Received by Variously Obiented Surfaces if ~ " ID - K IDn = the direct or beamed solar radiation, Btu per (hour) (square foot of receiving surface). ID. = the direct solar radiation normal to the sun's rays, Btu per (hour) (square^j foot of receiving surface). ' the sky or diffuse solar radiation, Btu per (hour) (square foot of receiving?, surface). This comes principally from the atmosphere itself as a conse^ " quence of scattering. Vertical surfaces also receive solar radiation by " reflection of direct and diffuse radiation from the ground and other objects:)!1 Such radiation is usually diffuse. The diffuse radiation strikes at olf% angles. /tf, h = total incident solarradiation, Btu per (hour) (square foot of receiving)? surface). ? K = cosine of the angle of incidence, 8. For a vertical surface, 8 is defined Fig. 1. y- Standardized, practical-purpose values of the direct solar radiation incident upon a plane perpendicular to the sun's rays at the earth's surfac^| _ ) 2 ft ^onV proposed standard for sea level, 20 n>m precipitable water vapor, i tn Hg partial pressure of ozone. ^Cr *9 deg north latitude on about August 1 dust particles per cu cm. norm8Hn^donn oo,,bb--sseervravltaiaowtniisoudbney*.Ao*nSmaH*bVo*E*u-tL-AaubgourasttoIr.y at Cleveland on cloudless days during which the observed d n ."ence values closely approximated the normal incidence values tabulated. absorptivity^of^ recommended design sol-ait temperatures* for New York City fora horizontal surface wjib CHAPTER 13 approaching or exceeding those for a clear atmosphere are often encountered during Cleveland summers, but with dew-point and maximum dry-bulb temperatures 10 to 15 deg lower. Considerable judgment, therefore, 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 K,Table 5. Values or the Cosine or the Incident Angle, toe Variously Oriented Walls and a Horizontal Surface a e pSh P *5 g 0O5 z . -.0a Q U Sun Time AM - i 6 a ah. :6 pad. 7 - '5- ' 8 .4 . .. 10 11 .12. ; ' 2, 1 . : : : N 0.267 0.144 . 0.030 Cosine K of the Incident Angle NE 0.862 0.752 0.604 0.427 0.234 0.039 E 0.952 0.919 0.824 0.672 0.476 0.246 0.000 SE 0.484 0.548 0.561 0.524 0.438 0.310 : 0.147 s 0.068 0.144 0.192 0.208. i 0 % 0a Q. 0 5 a.m.7 pad.. ` 6' -6 ' ?. 75 8 ' '' 4 9 3. 10 2 It l 12 0.406 0.237 . 0.079 . 0.934 0.840 0.705 0.533 6.387 0.129 0.914 0.951 0.919 0.824 0.673 0.475 0.000 0.358 0.505 0.594 0.631 0.614 0.542 0.424 0.265 0.069 0.190 0.292 0.354 Q.376 .. 5 a.m. . 7 pad. .6.385, I '6 07 '6 ` 5 0.199 ' 0.010 84 0a 9 P 10 s 11 12 3 2 1 0.923 ' 0.813 0.656 0.465 0.252 0.030 0 920 0.951 0.918 0.824 0.673 0.475 0.247 0.000 0.378 0.532 0.643 0.700 0.699 0.642 0.532 0.375 0.166 0.316 0.433 0.505 0.530 i PM -- N NW w sw 8 SW 0.147 0.076 0.265 0.183 0.375 SE Hobie. 0.156 0.367 0.669 0.737 0.866 0.951 0.978 0.009 0.199 0.391 0.568 0.713 0.829 0.903 0.W7 }x $? 0.078 0.233 0.399 0.545 - 0.669 0.766 . 0.829-. 0.848 'P `J/j Hobie..,; latitude on August 1 (18 deg declination, north) are given in Table 4 foy^ the two types of atmospheres. These are based upon observations made?/ on cloudless days in Cleveland over a period of several summers. Sinces* less extensive data were available for industrial atmospheres, there is more/j| uncertainty regarding these values. In both instances, the values included 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 buildings may reduet diffuse irradiation by partial,shading. V3p 7 - Calculation Tables ' ' The irradiation of a surface by the sun is the product of 7d,,, the direct * normal radiation (see Table 4), and the cosine K of the incident angle,-? For horizontal surfaces, the cosine K equals the sine of the solar altitude; For vertical walls, A is a function of the solar altitude /3 and the was solar azimuth y, thus -s ' K = COS 9 = COS/3 COS 7 tf) coonng l.oaa 277 These three angles are defined in Fig. 1. 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 <t>, the solar azimuth, is required. In this discussion, <j> will-be measured east from south in the morning, and west from south in the after Table 6. y,Values of the Wall Solar Azimuth, for Variously Oriented Walls and Solar Altitude . . Computed for 18 Deg Declination, North (August 1) Sun Time AM i 6 a.m. 6 p.m. 75 84 93 10 ' 2 1112 1 5 a.m. 7p.m: 66 75 84 190 23 1121 1 5 a.m. 7 p.m. 27 65 Solas Altitude 0 Degrees Azimuth Angle y, Degrees 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 .74 81 shade 66 76 85 shade NE 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 16 29 17 38 24 14 5. 5 16 -31 55 23 12 0 12 25 42 64 90 SE SW 61 54 47 shade 84 28 73 - .7 45 52 0 shade 45 1 69 59 50 . 8hade 40 85 29 74 . 1104 45 59 shade 35 0 80 45 57 45 33 20 65 3 19 45 48 shade 26 0 71 45 PM - NW W noon. Hence, <f> 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 <j> equals 90 + 7, that is, 4> is greater than 90 deg. The wall azimuth ^ is the angle, measured east Irom south to the per pendicular to the wall for walls which have an easterly component, and west from south for those having a westerly component. For example, ^ for a wall facing northeast is 135 deg. The wall solar azimuth y may be found according to the following schedule: For walls facing east of south: 7 ^ ^ a.m. y <t> + ^ p.m. For walls facing west of south: . y = ^ -f- $ a.m. y * ^ 7" $ p.m. negative values of y as if they were positive. If 7 is greater than deg, the wall is in the shade. Values of K for other seasons and latitudes may be found in the literature^ or may be computed from data given in Hydrographic Office Bulletin Wo- 214, Tables of Computed Altitude and Azimuth3 and the Ephemens Date April 1. April 15 May 1 May 15 Declination I Date 4.5 10.0 15.0 19.0 June 1 June 15 July 1 July 15 Declination 22.0 23.5 23.0 21.5 Date j Aug. 1 Aug. 15 Sept. 1 Sept. 15 of *. Su. Table 7 shew, the variaboa o. ^ beelb 18.0 14.0 8.5 3.0 months ordinarily requiring cooling. , . fi-on n m at 40 deg north latitude on Example 1: Find the solar azimuth <f> at . P- From Table 6 in the column of .for a .all facing west.**,-6.00 p ; i EFaT iWVilK-* * -""`w w a .j. - * *"* - -- " ,0:0; " "7" 1152r,SS~- a,jt-stfBS.wa*' iC = COS 0 COS 7 Example S: Find K for the .all in Example 2 at 3:00 p.is therefore Solution: The solar azimuth >a 65 deg west. 1 . 65 + 18 = 83 deg. The angle P is 42 deg. 65 + X = cos 42 X cos o8o3 = n0.774433 vX 0u-1i22 = 0.091. -p w M . - - - <* - ,l- ""*7 1 . /D = X X ina = 0.557 X 273 = 152.0 Btu per (hr) (sq ft)- By linear interpolation, the diffuse irradiation is ' = 25 + J8 (33 -- 25) = 26.6 Btu per (hr) (sq ft). : The total solar irradiation is ,m Jt = 152 0 + 26.6 = 178.6 Btu per (hr)(sq ft). ,,=L-=371=-=.^| The calculation oi neat Df the diurnal cycles oib^ exposed to the weather, requires iirrrraaddiiaattiioonn ^^dd aaiirr tteemmppeerraattuurree.. TThheess yy and other factors lead toJ|g hheeaatt ^fiow iinntto tthhee wweeaatthbeg(^^ oeriodic vanation in the instantaneous heat flow into tbeg- ** " * IKTuSSsurface, and a related P^'fJ^at capadtyand other factors th^ air conditioned space. Bee phase and unequal m amphtu y0 lhe weather ""1 tk a building, it is necessary to know. i. Th, m - 2 The MOW < 3. The intensity of diffuse or sky solar radiation sir ,ta g ^ ->- M m ^ Cooling Load 279. Table 8. Summer Design Sol-Air Temperatures Used for Tables . . 9 and io .' Mean Sun Time `a Ratio: -7-- fto USol-Air Temperature Fahrenheit Degrees Any Sur Horn. North face East South West 0 0.225 0 0.225 0.125 0.225 0.125 0.225 0.125 12 Midnight 1 AM 2 3 77 77 77 77 77 77 77 77 77 76 76 76 76 76 76 76 76 76 76 76 76 76 76 76 76 76 76 75 75 75 75 75 75 75 75 75 4 74 74 74 74 74 74 74 74 74 5 74 74 74 . 75 80 74 74 74 74 6 74 76 74 no 93 74 74 74 74 7 . 75 91 75 123 100 75 75 75 75 8 77 106 77 126 103 82. 78 77 77 9 80 119 80 125 104 93 86 80 ' 80 10 ... 83 129 83 117 100 102 93 83 83 11 87 137 87 108 96 110 99 89 87 12 Noon 1 PM 2 3 90 142 90 93 144 93 94 140 94 95 132 95 92 92 114 104 96 92 93 93 115 105 110 102 95 94 111 104 124 111 95 95 104 100 135 119 4' 5 6 7 94 . 93 91 87 120 94 107 93 96 91 90 87 94 94 99 96 141 120 93 93 95 94 139 118 91 91 91 91 125 111 87 87 88 87 103 94 89 10 11 85 85 85 85 85 85 85 85 .85 83 83 83 83 83 83 83 83 83 81 81 81 81 81 81 81 81 81 79 79 79 79 79 79 79 79 79 24 Hr Avg tm 83.1 100.5 83.1 93.0 88.4 89.0 86.2 93.0 88.4 surface absorptivity, dimensionless: roof = 0.9; dark walls = 0.9. and light walls = 0.5. /<*> = unit convective conductance = 4.0 Btu per (hr) (F deg). ""** values in this column are magnitudes of to, the outdoor air temperature. 4. The absorptivity (or reflectivity) of the surface for diffuse or sky solar radia tion. "^he rate at which the surface emits radiation to the sky and other surroundings*. ^ rate which the surface absorbs-the low temperature radiation emitted Py fche sky and other surroundings by virtue of their temperatures and radiat ing characteristics. 7 The temperature of the surrounding air. 8 The temperature of the outer building surface. 9 convective conductance for heat transfer between the air and the building surface. The Sol-Air Temperature i^errelaticmship of the above factors can be considerably P ined through the use of the sol-air temperature concept. The sol- Cooling Load 281 5. Corrections. Par temperature difference when outdoor maximum design temperature minus-room is dif ferent from 15 deg. If the outdoor design temperature minus room temperature is different from the base of 15 deg, correct as follows: When the difference is greater (or less) than 15 deg add the excess to (or subtract the deficiency from) the above differentials. Pot outdoor daily range of temperature other than 50 deg. If the daily range of temperature is less.than 20 deg, add 1 deg for everv 2 deg lower daily range; if the daily range is greater than 20 deg, substract 1 deg for every 2 deg higher daily range. For example, the daily range in Miami, Florida is 12 deg or 8 deg less than 20 deg, therefore, the correction is + 4 deg at all hours of the day. , ,, Light Colors. Credit should not be taken for light colored roofs except where the permanence of the light color is established by experience, as in rural areas or where there is little smoke. When the exterior surface of roof exposed to the sun is a light color, such as white or aluminum (which absorb approximately 50 percent <md reflect 50 percent of the solar radiation) add to the temperature differential for roof in shade 55 percent of the difference between the roof in sun and roof in shade. When the roof exposed to the sun is a medium color such as light grey, blue or green, or bright red, add 80 percent of this difference. For solar transmission in latitudes other than 40 deg north, and in other tootU&s, The table values of tem perature differentials will be approximately correct for a roof in the following months: Nobth Latitude Lati- tude (deg) Months 0 All Months 10 All Months ' 20 All Months except Nov, Dec. Jan 30 Mar, Apr, May,- June, July, Aug. Sept 40 April, May, June, July, Aug 50 May, June, July South Latitude Lati' tude (deg) Months 0 All Months 10 All Months 20 All Months except May, June, July 30 Sept. Oct, Nov. Dec, Jan. Feb. 40 Oct, Nov, Dec, Jan, Feb 50 Nov, Dec, Jan - For other months, the total temperature differential (fx) may be approximated by the use of the following formula: tx 1* + (tv -- tf) where t = temperature differential for the same roof in shade for desired time of day; obtained from Table ty = maximum solar transmission through glass. Btu per (hr) (sq ft) for flat skylight in July, 40 deg north latitude (Note: this is maximum value irrespective of time). . f> = same as ly except use the maximum value (or flat skylight, for month, and latitude desired for tx- tv = temperature differential for particular roof exposed to sun for the desired time of day from Table 9. (.Note that this makes adjustment only for solar radiation and that there may be additional correction for out door temperature.) , Light Construction Medium Construction Heavy Construction of tbe vrood. XOTES FOR TABLE 9 Total beat transmission from solar) f c ] (Heat transuussioBj'' . radiation and temperaturedifference1 lEquivalent temperature! w /coefficientforsufftw... sxputnawm. outside and room air, Btuf jdifferential from above/ * lmer Btu per (brik; . per (br) (sq it) ol roof area ) (table ! l(sq ft) (F deg) 1. Source. Calculated by Mackey and Wright method (aee reference list) and adjusted after studyb?*^ ASHVE original test data. Estimated for July in 40 deg north latitude. <For sol-air temperatures M^ed calculations see Table 8.) For typical design day where the maximum outdoor temperature is 95 F &Jf minimum temperature at night is approximately 75 F (daily range of temperature, 20 F) mean 24 hr perature 84 F for a room temperature of 80 F. All roofs have been assumed a dark color which absorbs percent of solar radiation, and reflects only 10 percent. ' 2. Application. These values may be used for all normal air conditioning estimates; usually correction, in latitude0 deg to 50 deg north or south when the load is calculated forthe hottest weather. 5 explains bow to adjust the temperature differential for other room and outdoor temperatures. -> 3. Peaked Roofs. If the roof is peaked and the heat gain is primarily due to solar radiation, use for 4. Attics. If the ceiling is insulated and if a fan is used in the attic for positive ventilation, the totality area of the roof, the area projected on ahoriiontal plane. ^:<T**^rtialfor a roof exposed to tbesun may be decreased 25 percent. . air temperature 4 is the temperature of the outdoor air, which, in the absence of all radiation exchanges, would give the saine 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 other outdoor sur roundings, and convective heat exchange with the outdoor air. The sol-air temperature data5 8 10 as developed by Mackey and Wright or an industrial atmosphere were used as a basis for preparing Table 8 snowing summer design sol-air temperatures. Sol-air temperatures may so be estimated from experimental observation of surface temperatures o walls and roofs which appear in the literature.11-12 Both analytical and xpenmental studies have been made on the problem10 of heat flow through 0 a an<f roofs. Those concerned with a further study of the details of m estbnates in particular relation to periodic heat flow will find _ u?, ' value and interest in the reports of experimental studies of these chnn*18'10 u'12'I3, u'16 The reader may also refer to the Cooling Load and tei"f^ ^HE ^DIDE 1952 for the theory of heat flow through walls Table 10 Total Equivalent Temperature Differentials for Calculating .` Heat Gain Through Sunlit and Shaded Walls Sun Time North Latitude Wall Facing NE E SE S SW W NW N (Shade) NE E SE S SW w NW N (Shade) NE E SE S SW W NW N (Shade) NE E SE S SW W NW N (Shade) NE E . SE S SW w NW N (Shade) NE E SE S SW - WNW N (Shade) A.M. P.M. Exterior color of Wall--D = dark, L = light South Latitude Wall Facing DD D Dl D L D L Frame ' 10 14 6 -4 -4 24 38 26 4 12 18 16 0 14 32 28 22 10 16 18 12 12 12 24 10 12 16 14 14 16 14 14 14 14 14 14 14 14 14 10 10 10 10 10 10 30 20 26 20 16 14 10 10 6 6 6 6 4 6 4 6 2 2 -4 -4 -2 -2 6 6 4 4 26 22 40 28 42 28 24 20 6 4 20 - 32 12 10 40 24 21! 21 41! 40 34 26 22 34 22 24 4 10 10 14 14 12 12 8 8 6 8 e 4 4 8 4 4 2 2 2 0 2 0 4 In. Brick or Stone Veneer -f Frame SE E NW W bW S (Shade) 24 12 14 10 -4 -4 --2 -2 20 31 28 12 10 17 16 6 10 14 6 14 12 12 10 12 14 14 14 14 12 12 12 12 10 10 10 26 16 18 14 14 14 12 12 10 24 16 25 18 20 16 12 12 - 8 6 4 -4- -4 -2 -2 2 4 2 0 2 2 2 0 12 10 8 6j 8 32 22 36 26 34 fi 26 lfi 40 28 42 6 12 12 30 22 34 6 10 10 12 12 12 24 28 24 12 10 16 12 8 8 14 10 8 6 6 4 In. Hollow Tile or 8 In. Cinder Block 20 10 24 12 16 8 20 0 o -2 -2 16 26 20 10 14 12 10 20 20 6 12 14 12 12 14 10 10 12 14 14 14 12 12 12 12 14 12 10 10 10 12 6] 24 14 26 16 20 14 12 10 6 6 4 4 12 10 ?6 18 30 20 26 18 4 1C fi 18 14 30 22 32 22 2 fi 6 12! 1(J n 18 30 22 0 0 6 6 10] 10 10 10 10 10 8 In. Brick or 12 In. Hollow Tile or 12 In. Cinder Block 8 10 10 14 18 18 8 10 12 10 14 16 6 8 12 10 14 12 8 10 10 10 14 12 10 10 10 10 32 12 8 10 10 2 10 6 16 10 16 12 12 10 10 8 4 10 6 10 26 02 6 12 6 14 48 26 8 20 12 24 16 20 14 8 20 16 24 16 24 16 6 10 8 lfi 14 lfi 14 6888866 12 In. Brick 868684 12 8 12 8 12 8. 10 6 10 6 10 6 868664 4 12i 6 12 8' Hi 10! 14 46] 182] 84! 14 10 10 12 8 4 6 10 8 12 68 42 6 10 8 12 68 22 6 8 4 2 101 10 4| 11800| 2; ' 2 2 , 642r 10 6} 10| 4| 2 2! In. Concrete or Stone or 6 In. or 8 In. Concrete Block 16 24 16 4 8 12 10 1 14 24 18 12 8 12 12 6 10 18 18 16 6 10 12 12 12 14 14 18 8 10 12 32 12 14 12 14 10 10 10 12 10 12 12 10 8 10 10 8 Si 10 10 8 6 8 8 6 6 6 4 0 2 4 0 8 8 2 4 6 4 2 14 10 22 12 . 8 20 6 6 12 446 16 14 10 6 24 2fi 2<J 8 16 lfi 14 8 22 26 22 6 16 lfi lfi 6 10 14 8 4 8 10 6 4j SE N. Nh NW W SW S (b Mi Cooling Load 283 Table 10- Total Equivalent Temperature Differentials for Calculating Heat Gain Through Sunlit and Shaded Walls--Concluded. North Latitude Wall Facing NE E SE S wNW N (Shade) Sun Time A.M. Exterior color of Wall--D = dark. L = light South Latitude Walt, Facing D L D L D L D L D L D L D lL D i L lD 12 In. Concrete or Stone 6 4 6 2 6 6 2 6 4 2 14 8 14 8 10 8 10 8 12 10 10 18 10 lfi 12 16 10 12 10 14 10 14 8 16 10 16 10 14 10 12 10 12 42 6 14 10 16 12 14 10 10 8 SE E NE N 8 4 8 4 6 4 6 6 10 48 6 10 6 10 6 12 8 18 14 20 14 18 12 8 16 10 24 14 22 NW W 6 4 6 4 8 6 10 8 18 12 20 14 SW 0 0 2 2 4 4 6 6 8 8 6 6 S (Shade) NOTES FOR TABLE 10 Total'Beat'transmission from solar1 "p P.t_e_n_o,fu_m__.rabdeiatwtioenenanoduttseimdepearnadturreoodmiffeareirn, cBet!u{ per (hr) (sq ft wall area) NOTES': (Equivalent temperature differential from above [Heat transmission J coefficient for wall, table [ ^ {Btu per (hr) (eq J (ft) (F deg) 1. SOURCE. Same as Table 9. A north wall has been assumed to be a wall in the shade; this is practi cally true. Dark colors on exterior surface of walls have been assumed to absorb 90 percent of solar radiation and reflect 10 percent; white colors absorb 50 percent and reflect 50 percent. This includes some allowance for dust and dirt since clean, fresh white paint normally absorbs only 40 percent of solar radiation. 2. APPLICATION. These values may be used for all normal air conditioning estimates, usually with out corrections, when the load is calculated for the hottest weather. Correction for latitude (Note 3) is neces sary only where extreme accuracy is required. There may be jobs where the indoor room temperature is considerably above or below 80 F, or where the outdoor design temperature is considerably above 95 F, in which case it may be desirable to make correction to the temperature aifferentials shown. Thesolar intensity on all walls other than east and west varies considerably with time of year. . 3. CORRECTIONS. Outdoor minus room temperature. If the outdoor maximum design temperature minus room temperature is different from the base of 15 deg, correct as follows: When the difference is greater (or less) than 15 deg, add the excess to (or subtract the deficiency from) the above differentials. Outdoor daUp range temperature. If the daily range of temperature is less than 20 deg, add 1 deg to every 2 deg lower daily range; if the daily range is greater than 20 deg, subtract 1 deg for every 2 deg higher daily ran-?e. For example, the daily range in Miami, Florida is 12 deg, or 8 deg leas than 20 deg; therefore, the cor- . rection is +4 deg. _ . Color of exterior surface of wall. Use temperature differentials for light walls only where the permanence ot the light wall is established by experience. For cream colors use the values for light walls. For medium colors interpolate half way between the dark and light values. Medium colors are medium blue, medium . bright red, light brown, unpainted wood, natural color concrete, etc. Dark blue, red, brown, green, etc., are considered dark colors- Forlatitudes other titan 40 deg north; and in other months. These table values will be approximately correct jr the east or west wall in any latitude (0 deg to 50 deg North or South) during the hottest weather. In the lower latitudes when the maximum solar altitude is approximately 80 deg to 90 deg (the maximum occurs at P) the temperature differential for either a south or north wall will be approximately the same as a north, or shade wall. The temperature differential Ox) for any wall facing, and for any latitude for any month may approximated as follows: ^ tx -- tg 4" X (tw -- tg) vhire fg = fi 1te0-mpe.rature differential for the same wall in shade for desired time of day; obtained from Table maximum solar radiation intensity transmitted through glass, Btu per (hr) (sq ft) for particular wall facing, in July, 40 deg north latitude (note: this is maximum value irrespective of time), same as h except use the maximum value for wall facing, for month, and latitude desired for <x. temperature differential for particular wall facing, for the desired time of day from above table. {Note that this makes adjustment only for solar radiation, and that there may be additional correction FOR for outdoor temperature.) ' . . . INSULATED WALLS use same temperature differentials as used for uninsulated walls. . '84 CHAPTER 13 Table 11. Summer Coefficients of Heat Tbansmission V of Feat Roofs Covered With Built-Up Roofing* Blu per (hour) (square fool) (F deg difference between the air on the two sides) 1 t'np-dk- ____,, riTAF Ceiling not shown i 'Thickness ot Roof Deck | (Inches) Insolation on Top of Deck (Covered With Built-Up Roofing)' No Ceiling'-- Underside of Roof Enposed Furred Ceiling vritb Air Space, Metal Lath snd Plaster -------------- --------------------- - oemoiiknbaoltohridckinnseuslsa0ti1ownoiswujsjehdb,^thWenc.o.e,ff_icient U may be decreased W perveu*. PRACTICAL TABLES FOR CALCULATING SOLAR HEAT GAIN THROUGH WALLS AND ROOFS The analytical10 method reported by Mackey and Wright was used by . Stewart16 to obtain temperature differentials based on Table 8 and showfe in Tables 9 and 10. These analytical procedures, as well as those using* Cooling Load 285 Tables 9 and 10, presented here, yield generally higher rates of heat gain than reported for Pittsburgh in early A.S.H.V.E. experimental studies. Current authoritative opinion indicates a preference for analytical calcu lations. Thermal and physical properties of materials used in these tables are given in a paper.16 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 inside film conductance of 1.65 Btu (hr) (sq ft) (F deg). A reduction was made in the temperature differentials for roofs amounting to some 20 percent of solar radiation as explained by Stewart.16 This was to compensate for several factors, one of which is the radiant heat lost to the sky which is not included in the Mackey and Wright method. Recent experimental work by Parmelee17 and previous work by Brunt18 gives data showing the magnitude of this radiant heat loss from a roof or wall to the sky. Temperature differentials for roofs probably would be reduced be low those shown in Table 9 whenever the radiant heat lost to the sky is in cluded in calculation of sol-air temperature. The temperature differentials for roofs were based on an inside surface conductance of 1.65 because the charts prepared by Mackey and Wright10 used this value, and it was not considered practicable to repeat their work using a different film coefficient. An examination of the values given in their paper indicates that the tem perature differential would be. changed very little1 even if a value 1.20 were used instead of 1.65. But to obtain the heat flow rates through roofs, more accurate values will be obtained if the overall heat transmission coefficient is calculated using 1.2 as the inside film conductance of heat transfer in summer. - The roof coefficients of transmission for summer shown in Table 11 are based on surface conductances /cro 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 representative 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 mside conductance 1.20 is used because the convective portion of the film conductance factor of downward heat flow from a horizontal surface is appreciably less than the winter conductance, which applies when heat is flowing upward. Since there is little difference in wall 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 recommended that the overall coefficient U, for vmlls, be taken directly from the tables in Chapter 9 in which they are based- on an outside film conductance of 6.0, corresponding to a 15 mph wind velocity. Advantages of Equivalent Temperature Differential 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 5 to 7. .: pjjifbe total sensible heat flow is obtained by multiplying the overall heat trans- T,,v,,10n,,<!oefficient, 17, and the equivalent temperature differential indicated in -ables 9 and 10. . t;0^' Tbe temperature differentials listed for a few representative types of construc- ay be used on all classes of walls and roofs, even though the overall heat trails- 1954 Guide |J 286 CHAPTER 13 . Sr mission coefficient is different, provided the structure has thermal and physical : properties similar to one of those listed in Tables 9 and 10. .7 3. Adjustments can be made, according to instructions given in the footnotes, for room and outdoor conditions different from those on which the tables are based. Examples of Use of Equivalent Temperature Tables , Example 5: Given: A roof is constructed of 6 in. of stone concrete with. 2 in., of insulating board and tar felt roofing f in. thick, and is exposed to the sun. The loca tion 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 inside tem perature SO F. , \. . ' Solution: From Table 9 in 2 p.m. column for 6 in. concrete plus 2 in. insulation, find the total equivalent temperature differential 34 deg. The overall heat trans- sun_ SURROUNDINGS ' transmitted . , OOUUTTDDOOOORR RAWATWN^ ^ (WAVE LENGTHS UNCHANGED) JRANSMITTCP INDOOR (pun INCIDENT INDOOR RADIATION-- REFLECTED > INDOOR - ruiTftftftQ rnUVtenON to<t^o- iirrrn OUTDOOR RADIATION, thermal capacitance or CLASS _ THEN TRANSMITTER ir--rr-- IMDQftR r/^MVTCTION t*i<u ' V > ii EMITTED INDOOR RADIATION r (DIFFERENT DISTRIBUTION' OF ENERCT VS.WAVE LENGTH THEN TRANSMITTED) .. n r;;i: to " OUTDOOR AIR TEMPERATURE t-o OUTDOOR GLASS - SURFACE TEMPERATURE ti -- INDOOR AIR TEMPERATURE tNOOOP GLASS- SURFACE TEMPERATURE Fig. 2. Instantaneous Heat-Balance Conditions on a Glass Section k #i T*!tmission coefficient for summer is taken from Table 11 and is found to be 0.13. heat flow rate equals 34 X 0.13 -- 4.42 Btu per (hr) (sq ft). Example 6: For the conditions of Example 5, find the rate of heat flow into buildfvjc ing at 2:00 p.m. during July for design temperatures of 105 F (outdoor) and 78 F (ib-.|| door). Daily range of temperature 30 deg, i.eoutdoor temperature minimum-61J&J 75 F which occurs at 4:00 or 5:00 a.m.; this being 30 deg less than the maximum. ' Sg! Solution: Make correction in equivalent temperature differential in accordance^ witThhNeocteor5reinctiToanbfloer92a7sdfeogllodwessi:gn temperature difference is (27 -- 15) = + 12. ( 30 -- 20\ ------ 2-- ) = -- 5- jrv*' fl? 4P Net total correction is + 12 -- 5 = + 7. , 5.32 Btu per (hr)l The heat flow rate at 2:00 p.m. therefore is (34 + 7) X 0.13 < (sq ft). . `It A method of determining heal flaw rates, when structure is not given ^0 Tables 9 or 10, is illustrated in Example 7 which follows. Cooling Load 287 Example 7: A 4 in. stone concrete roof covered with an average depth of 4 in. cin der concrete (i = 4.9) on which is placed a f in. thick felt roof with $ in. pitch and slag 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 heat flow rate at 2:00 p.m. for a day in July. Solution: For the purpose of selecting the equivalent temperature 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 p.m. column of Table 9. Calculate the overall heat transmission coefficient U (see Equa tion 3 of Chapter 9) of the roof as follows: 1 U =------------------------------------------------------ = 0.33. 4 _4_ 0.375 0.50 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 schematically in Fig. 2. The net heat gain for the indoor space is the result of several contributing phenomena. Some observations concerning the behavior of glass with respect to radiant energy will lead to a better understanding of the heat-balance relation. To various degrees glass transmits radiation having wave lengths between 0.29 and 4.75 microns. Of the portion not transmitted, part is absorbed, and the remainder is reflected. Outside these limits glass is opaque, absorbing approximately 94 percent and reflecting 6 percent. Only a negligible amount of radiant energy from a surface at 450 F has a wave length shorter than 4.75 microns. It is therefore convenient to treat all forms of solar radiant energy separately from radiant energy from other sources, so long as the temperature of these sources is not over approxi mately 450 F. The complete heat-balance for a glass section can be expressed for a unit time interval as follows: [Total heat flow, 1 ^ [Transmuted, 1 [^dUdiaUve^xchangesItl (2a) ^through glass sectionJ [jjolar radiationj [_the m^00T surface J The second term of the right side of Equation 2a can also be expressed by a heat balance equation as follows: PHeat flow by convective"! and radiative exchanges j Lat the indoor surface J "Absorbed "| ["Radiative exchanges be- " solar tween outer surface of glass ! _radiation J Land outdoor surroundings _ 'Convective exchanges "] ["Heat storage"] =b between outer surface of within the I (2b) ^glass and outdoor air J Lgla-ss sectionj Equations 2a and 2b can be combined and expressed in symbolic terms 2y Equation 2c. Tabular values of the two bracketed terms of Equation * are presented later in this section for various types of glass for specific d^gn conditions. (9/A) = [T; dId + Td/d] + [<*d/d + ad/d + gofts -- Cjt0RSO - /eo (to - o) -.5], Btu per (hr) (sq ft) (2c) `r&tru. instantaneous rate of beat flow, Btu per (hour)(square foot), transmittance of glass for direct and diffuse solar radiation, respectively, incident direct and diffuse solar radiation, respectively, Btu per (hour) a(sbqsuoarpretafnocoet)o.f glass for direct and diffuse solar radiation, respectively, p <*d 5 .. tgo s emissivity of glass at temperature <. low temperature radiant energy falling on glass from outdoor surround R. lionwgs,teBmtupepreartu(rheoruar)di(asnqtuaerneefrogyote).mitted by a surface with emissivity Kgo oeuqtudaolotor c1o.n0vaetctteivmepceornadtuurcetatn^c.e, Btu per (hour) (square foot) (Fahren fco heit degree). ho temperature of outdoor surface of glass, Fahrenheit degrees. to = temperature of outdoor air, Fahrenheit degrees. rate at which glass stores energy, Btu per (hourXsquare foot). Table 12. Tbansmittances and Absobptances of Comuon Window Glass fob Dibect and Diffuse Solas Radiation Angle of Incidence, . 0,-DEO Single Sheets D . TWO AIR-SPACED SHEETS aD ' --------tD Outdoor Sheet Indoor Sheet --- Fob Direct Radiation * 0 20 : 40 50 60 70 -80 00 " - 0.87 0.87 0.86 0.84 0.79 0.67 0.42 0.0 0.05 0.05 0.06 0.06 0.06 0.06 0.06 0.0 0.76 0.76 0.74 0.72 0.66 0.52 0.25 0.0 0.06 0.06 0.06 0.07 0.07 0.07 0.07 0.0 , Fob Diffuse or Set Solar Radiation 0.04 0.04 0.04 0.05 0.05 0.05 0.05 0.05 f , l! ... Si ; 1 *1 - 0.79 | 0.06 I o.ss 0.07 0.05 m iL Transmissivity and absorptivity vary with both wave length of tbegt? incident radiation and incident angle. Values of r and a for a single shtjdt-f- of the average ordinary drawn window glass are given in Table 12 for.a;T standard distribution of solar energy.4 Values for two air-spaced shee|y are also given. Normal incidence transmittance values for some coigy-j monly-used types and combinations are given in Table 15. Some vanftr-V tion in these values can be expected in practice due to variations' manufacture and in solar energy distribution. However, a change1 jag:; transmissivity causes an approximately equal and opposite change lipJ / absorptivity. Hence, the total heat flow is not greatly altered. Trans-T' miittance data for other types of glass and various patterns of 8-in. gt&s&, block are given in A.S.H.V.E. research papers.1*- ** ** ** * As stated earlier in this chapter, present data as to the value of'^~ are inadequate, so for the present it is suggested that /,, be increased h'T include radiation, and the term be disregarded. It practicable to give values of <S in this chapter. However, for ordinapt- glass, the value of S is small. . Jgj* Fig. 3 is a graphical solution, for single glass, of Equation 2b. _ Oju|; absorbed solar radiation is considered, although low temperature radiattojjj Cooling Load 289 exchange and heat storage can be added algebraically to J. if such data are available. The small thermal resistance of the glass has been neglected. The heat flow rates are for a 75 F indoor temperature, an indoor surface conductance for convection f,,i as given by Equation 3, and an equivalent ssuurrff<aa-cc--ee-s--c-s-oe--nend- uLbc-yt-atitnhhiceee-. ggfll,oaassr; ss raaarrdeeiaaa.tss.issouun. mm./ee,idd, a--ttnos-; mrogariHdv'*iei;oa*nt4tAefbla'yjs Equation 4. a black body a-xIltlnlU.rdoUooOomrr air temperature. where fox = 0.27.(I,;:- U = 0.162 f (V+ 460V _ (k + 460y-| j LV 100,7 \ l00_,) J/ - ') (3) (4) tBi = temperature of indoor surface of glass, Fahrenheit. ti = temperature of indoor air, Fahrenheit. A more complete treatment of the problem is given in an A.S.H.V.E. research paper. Example 8: Find-the .total heat gain at 10 a.m. sun time for a single unshaded Bheet of common window glass in a wall facing 18 deg east of south on August 1 at 50 deg north latitude. The indoor temperature is 75 F, the outdoor temperature is 83 F. Use clear atmosphere radiation values and = 4.0. Solution: From Example 2, K is 0.557; hence, the angle of incidence, 0, is 56 deg 9min. From Example 4,ie = 152.0,14 = 26.6. By interpolation in Table 12, td is found to be 0.81, <*,, is 0.06; Td and an are 0.79 and 0.06, respectively. The beat gain due to transmitted solar radiation is (q/A), = 152.0 X 0.81 + 26.6 X 0.79 = 144.1 Btu per (hr)(sq ft). The beat gain by convection and radiation from the indoor surface is found from Fig. 3: ; from which 27* = 83 + 0 06 (152.0 + 26.6) /c 4 85.7 F (9/A)a = 11.5 Btu per (hr)(sq ft). From Equation 2a the total heat flow is (q/A) = 144.1 + 11.5 = 155.6 Btu per (hr)(eq ft). Design Tables for Flat Glass : Tables 13 and 14 give design values of instantaneous rates of heat gain for single 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. Table 13 represents the first bracketed term of Equation 2a; therefore, the values are dependent only upon values of / and t. Table 14 is the second term of Equation 2a, and is based, upon a 80 F indoor temperature and a dry-bulb temperature cycle, with a 95 F maximum as tabulated. The teteZ heat gain is the sum of the Table 13 and Table 14 values. In preparing table 14, convection and radiation heat exchange were'combined, and a combined surface conductance of 4.0 used. Corrections to be applied for 290 CHAPTER 13 1954 Guide Cooling Load 291 other design temperatures are given in Table 23 in a later section, Effect of Deviation from Design Conditions. ' ____ -------- v,* -aaaat UA1N l^MJE TO TRANSMITTED -DlRE and Diffuse ob SkySolab Radiation by a Single Sheet of Unshaded 1 Common Window Glass Tables 13 and 14 may be used for other types of glass with good accuracy, by using the factors given in Table 15. Table 13 values are multiplied by For Clear Atmospheres and 18 Deg Declinaiiont North (August 1) Note: For total instantaneous heat gain, add these values to the Table l values. the appropriate factor given in Table 15 to obtain heat gain due to trans mitted solar radiation. For glasses having a transmittance for normally incident radiation differing from the table values, factors may be found by linear interpolation. To obtain instantaneous rates of heat gain by con a Sun Time E* b AM -* _i i N .= Instantaneous Heat Gain in Btu per (hb) (sq ft) NE E SE S SW W NW Hoatz. vection and radiation, two steps are required. First, Table 14 values are multiplied by.the appropriate coefficient of X listed in Table 15. Second, Table 16 values are multiplied by the appropriate coefficient of Y listed in Table 15, and added to the first value. All convection and radiation `fs S 6 a.m. 6 p.m. 25 98 7 o8 Z9 5 4 3 23 155 16 148 16. 106 o 108 190 205 180 52 110 136 136 a 10 Q 11 n 12 2 1 17 18 18 54 128 20 . 69 19 19 116 78 35 5 5 10 10 14 21 13 15 5 10 13 15 5 10 13 15 17 71- 137 195 34 45 49 17 16 19 18 35 19 16 18 19 241 267 276 X 5 a.m. 7 p.m. 66 75 8 4 3 26 16 14 H9 a 10 o 11 12 =s= -- 3 1 15 ` 2 16 . 1 -- -0.7 17 - ' 7 116 149 129 : 79 31 18 17 6 131 195 205 180' 127 58 ' ' 19 . 2 67 124 156 162 148 113 64 0 7 11 18 0 6 10 12 0 6 10 12 0 6 10 12 1 25 77 137 42 69 90 98 14 16 23 64 14 16 17 19 14 .188 16 229 17 252 17 259 'M 5 a.m. 7 p.m. 66 O Z 7 8 5 4 ao 9 3 a 10 2 g 11 1 12 1 20 25 12 13 14 15 16 ' 16 54 128 139 107 54 18 16 16 54 149 197 202 176 124 57 18 20 81 136 171 183 174 143 96 3 8 12 32 72 110 136 144 3 7 10 12 14 16 42 96 3 7 10 12 14 15 16 18 3 7 10 12 14 15 16 16 6 34 80 129 173 206 227 234 ifI : i- ; r PM -* N NW W SW S SE E NE | Horiz. ' -It i Convection and Radiation Heat Flow fob Vertical Single Glass.; Fia. 3. - v gain values for double glass were computed for a j-in. air space. No great1!*} error is involved in cooling load estimates if these are used for double glass-)-, with other air spaces. . I'jfe Example 9: Find the total instaneous 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 Augustjp^l 1. The maximum dry-bulb temperature for design is 98 F; the atmosphere is clear&^Jl The indoor temperature is 80 F. Solution: From Table 13 the heat gain due to transmitted radiation is 148 per (hr) (sq ft) for common window glass; from Table 15, the factor for regular pla^K^I glass is 0.87. The coefficient of X in Table 15 is 1.0, while X is found from Table'lj,$ for common window glass for the same hour, orientation and latitude. The efficient of Y in Table 15 is 0.25, while the Y value is found from Table 16 for a west wall at 2:00 p.m. and 40 deg north latitude. The correction for design dry-bu*S|^ temperature is found from Table 23 to be 1.0 Btu per (hr) (sq ft) per degree difference^; from 95 F design temperature. The total instantaneous heat gain is, from tion 2a, q = 0.87 X 148 + 1.0 X 19 + 0.25 X 27 + 1.0 (98 - 95) = 157.5- Bttiu..p---e--r/u(h_\r)t--(sqr*f\t). ________.__ ____* vjBiu x> a vunvjibTJUW AND itADIATIO from a Single Sheet of Unshaded Common Window Glass For Clear Atmospheres and 18 Deg Declination, North (August 1) For 80 F Indoor Temperature Note: For total instantaneous heat gain, add these values to the Table 18 values. Time 5 a.m. 8 9 10 11 12 2 P'm- 4 7 8 DryBulb Deo F Degrees N 74 74 75 77 80 83 87 90 30,40,50 93 94 95 94 93 91 87 85 83 --6 --5 --5 --3 0 3 8 12 15 16 17 16 15 13 8 6 3 Instantaneous Heat Gain in Btu per (hr) (sq ft) NE 1 E --6 --6 --4 --4 --2 --2 01 24 46 8 10 12 12 15 15 16 16 17 - 17 16 16 15 15 13 13 88 61 3 36 1 SE --6 --5 --3 0 3 6 11 13 16 16 17 16 15 13 8 6 3 ----52 1 5 10 14 17 18 19 17 15 13 SW W NW Hob. -6 --6 --6 --6 --6 --6 --6 --5 --5 --5 --5 --3 --3 --3 --3 0 0003 3 3 3 '8 9 8 8 13 13 12 . 12 16 17 17 15 20 19 19 17 21 21 21 19 21 20 20 19 19 18 19 18 17 14 15 15 13 8888 6 6 66 33 33 292 CHAPTER 13 1954. Guide Table 15. Application Factors to Applt to Tables 13, 14. and,16 to.Obtain Instantaneous Rates of IIf.at Gain fob Various Types op Single Flat Glass and Combinations op. Two Sheets Of Flat Glass SbiTuan *t 1 tn.'! ' 1 Glass* Single Common Window Single Regular Plate Single Beet Absorbing Plate Double Common Window Double Regular Plate Beat Absorbing Plate Outdoonl Regular Plate Indoors ' / oo . Normal Inodbncb Transmittance ` - Factob to ' ' Apply to ' Table 13 0.87 0.77 0.41 0.76 1.00 0.87. 0.46b 0.85 .66b 0.37b Factor to Applt to Table 14 1.0(X)+0.0(7)" 1.0(X) +0.25(7) 1.0(X) +1.00(7) 0.6(X) +0.10(7) 0.0m +0.55(7) 0.0(X) +0.75(7) ' Common window glass i in. thick. Plate glass 1 in. thick. _ _ ,b For better precision, increase factors 10 percent when .* A values are Table 14 valueB. d Y values are Table 16 value*. YTable 16. Heat Absorbed in Glass. Values of to be Used with Factors in Table 15 and Table 17 in the Determination of Instantaneous Rates of Heat Gain Due to Convection and Radiation for Various Types of Single Glass and Combinations of Two Sheets of Glass Spaced at J in. . For Clear Atmospheres and 18 Deg Declination, North (August 1) Sun Time 5 a.m. 6 7 8 9 10 11 12 1 p.m. 2 3 4 5 6 7 Sun Tims] 5 a.m. 6 7 10 11 12 N 0 4 2 2 2 40 Degrees North Latitude ' 3 3 3 2 4 0 Degrees North Latitude 0 7 18 22 24 22 16 .6 .3 3 3 3 2 1 0 Values of 7 in Bru per (hr) (sq ft) " NE E SE 01 16 18 t 24 30 22 33 16 30 5 25 12 3 3 33 33 3 .3 22 1 1 -1 0 1 -0 0 9 20 25 29 27 21 15 3 3 3> 3 2 1 0 s SW W 0 1 2 2 8 14 18 . 19 19 16 10 4 2 1 '0 00 22 22 33 3' -3 ` 3 12 i 22 27 30 31 29 36 23 34 14 24 23 NW 0 2 2 3 3 15 23 27 21 3 Horiz. 0 3 11 21 32 37 42 45 44 41 35 26 17 6 1 Sun Time Latitude 5 a.m. 6 7 10 11 4 12 14 1 p.m. 21 2 `27 3 26 4 21 5 11 6 07 50b Degrees North Latitude SE 2 13 22 28 30 31 27 209 3 sw 01 0 1 22 32 13 3 20 3 25 5 27 17 25 26' 22 16 33 7 31, 2 1 17 \07 Values of 7 for 8 and 9 pm. are sero. b For N, NE, E, W, NW and horizontal use 40 deg North Latitude values. Cooling Load 293 luimuAuun J.'AVrUil& -- a xj a x\j j.aDAjZjO At A.DUS AO TO KJBTA stantaneous Rates of Heat Gain fob Vertical Single Sheets of Rolled Figured Glass Having Normal Incidence Tbansmittances and Listed Thicknesses (Smooth Side Indoors, Figured Side Outdoors) Glass Pattern Normal Incidence Transmittance Thickness, Inches Factor to Apply to Table 14 Hammered Hammered, etched both sides Deep ribs on f in. centers Hammered heat absorbing Hammered heat absorbing, etched both sides 0.75 0.67 0.77 approx. 0.21 0.14 Ha 1.0(X)* + 0.50(F)b.* Ha i.orjr) +0.65try1 Ha l.om + 0.50(F)* H l.on, + 1.16(F)' H 1.0 JT) + 1.40(F) * X values are Table 14 values 7 values are Table 18 values. . . c Use 0.40(7) for east and west giaan uS nv$ f0r ""1 "5 west Pk f K86 for east and west Use 0.95(7) for south glao^ : Table 18. Instantaneous Rates of Heat Gain Due to Transmitted Direct and Diffuse Solar Radiation by Unshaded. Rolled Figured Glass Multiply the Table IS Values by These Percentage Factors For Clear Atmospheres and 18 Degrees Declination, North (August 1) For - : SO, 40, and 60 Degrees North Latitude Note: To obtain total instantaneous heal gain add adjusted Table 13 values to adjusted Table 14 values Sun Time AM . i " 5 a.m. 7 8 9 10 11 12 7 p.m. Sun Time 5 a.m. 9 10 n 12 7 p.m. 6 5 4 3 21 f PM- Sun Time Hammered N. NW , ,,,, W, SW I NB SE 85 - 85 65 85 80 80 80 80 75 65 60 65" 65* Ribs on | In. Centers 60 60 60 60 60 N, NE E, SE 60 60 55 35 35. 35b 45b Hammered and Etched Heat Absorbing Hammered and Etghbd N, NW w, sw NE E SE 3 60 65 60 65 60 60 60 55 60 50 75 75 70 65 55 55 50 65 65 55 60 60 60 60 50 60 60 60 55 50 55 50 60 50 50 50 60 60 50 50 Hammered Heat Absorbing 25 25 25 25 25 25 25 25 N, NE E. SE 25 25 25 25 20 20 20 20 SW Decrease values 10 percent for 30 deg latitude; increase 15 percent for 50 deg latitude b Increase values 1 percent for 50 deg latitude i - \r 294 CHAPTER 13 1954 Guide Table 19. Description of Glass Block Patterns A - Outdoor surfoce Y - 0- Indoor surfoce -E-Covity partition Bleoation Section of Hollow Glass Block to Indicate Location of Surface Patterns - --Smooth Face Smooth Type IV--Light-Diffusing A, D: Close pitch deep horizontal Wide vertical ribs or flutes corrugations Wide horizontal ribs or flutes B, C: Vertical light diffusing prisms None E: None r.f. I Type IVA--Light Diffusing Type II ---Semi-Light Diffusing - Same as . IV except corruga A, D: Narrow vertical ribs or flutes tions vertical B, C: Etched or stippled E: None .` . Type V --Light Directing A, D: Close pitch deep vertical cor Type III -Light Diffusing A, D: Narrow vertical ribs or flutes B, C: Etched or stippled . E: Glass fiber screen B, C: B: rugations Horizontal prisms None light directing Table 20. 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 tffei >#f For Clear Atmospheres and 18 Deg Declination, North (August 1) Note: For total instantaneous heat gain add these values to Table 21 values iitf - - ---------------------------------------------------------------------------------- -M Sun Time Instantaneous Heat Gain in Btu per (hr) (sq ft) ' --Up .N NE SE . S sw w 7 p.m. 4 45 5 59 5 42 5 25 6 12 68 66 N I NW 2 22 4 5 33 44 6 55 9 10 9 66 7 8 6 7 00 22 44 5 .4 0 2 4 4 10 5 5 15 18 5 7 6 6 17 13 6 1 11 3 4 7 2 4 4 2 4 4 16 5 25 6 32 10 34 . 20 5 5fi 6 i s j SE i E 5e -,Ssai MS 1 2 \4 b; 6| 6-^4 " Cooling Load 295 Table 21. Instantaneous Rates of Heat Gain by Convection and: Radiation from Unshaded Walls of 8-in. Hollow Glass Block of Patterns Type I, II, III, IV, IVA and V* For Clear Atmospheres and 18 Deg Declination, North (August t) : , For 80 F Indoor Temperature ' . Note: For total instantaneous heat gain add these values to values in Table 18, or Table 80 adjusted by Table 22 factors. DryBulb Fahr. Instantaneous Heat Gain in Btu per (hr) (8q ft) SE SW W NW --3 --3 --2 --2 0 '0 2( 1 40 Degrees North Latitude 33 65 8 .7 12 9 28 . 11 41 17 44 30 42* 35 35* 29 21* 15 74 43 s swSun Time DryBulb Latitude SE Latitude SE S SW 3Qb Degrees . North Latitude --3 --3 --3 1 --2 --2 11 --1 20 0 0 26 1 2 29 4 26 8 5 18 12 7 10 21 15 16 . 16 30 12 14 39 12 a 13 11 43 41 10 9 32 6 6 15 446 333 5Gb Degrees North Latitude --3 --3 --2 --2 00 61 15 2 22 4 28 17 31 31 32 . 39 28 43 20 44 12 43 10 36 7 23 4 10 3> 3 7 and`8oar.tmyp. ebsyI1I.I4,0I,Van, dIVwAesatnwdaVil vpaalutteesrnfosra5n,d63a0n,d407 apn.md .5b0yde1g.2l5a.titudes, multiply east wall values for t b For N, NE, E, W and NW use 40 deg North latitude values. . Design Tables for Rolled Figured Glass Tables 17 and 18 give design values of instantaneous rates of heat gain for a number of common patterns of single vertical sheets of rolled figured ggllaassss.. TThhee ttaabbllee_ss__aa_rree__ff_oomrr aaossuooigllaaierr ddveeccrtlliiicnnaaalttiiosonnneeootffs11o88l dHroeeogll-e, dwwhWfiigVcuh>recdorresponds tfoo a9 nv,o--m:inal A ugust 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 13 and 14. The heat gain due to transmitted solar radiation is found by multiplying the Table 13 values toayn the aaPpPprrooxx'immaattee pp__ee_rr_cc__ee_nn_tt_aaggeess eg-iivveennUJiinnHiTrUra"JbKtrl,lep~iy11if80lg. . --------------------- Tn'o~ o' lb`tain instan- m nU,S rates f heat gain by convection and radiation, Table 16 values are u "Pued by the appropriate value of Y from Table 17 and then added to 296 CHAPTER 13 Table 22. Instantaneous Rates op Heat Gain Dub to Transmitted Direct and Diffuse Sglab Rauiation bt Unshaded Wajuls op 8~i'n HollowGla^s 1 Block of'Ttpbs II, III, IV; IVA and V Patterns ;'t Multiply the Table 20 Values for Type I by These Percentage Factors For Clear Atmospheres and 18 Deg Declination, North (August 1) ' For SO, 40, and 5Q Deg NorthLatitude `' ' Note: To obtain total instantaneous heat gain add adjusted Table 20 values to the Table 21 values. Instantaneous Heat Gain Dub to TaAsaMirret* Solar Radiation as a Percentage qs Tyee i Pattern Sun Time Son Timb I' "Ttpb "II "Pa--t--t---e- rn N. NW. I Am W,8W 1 E SE S 100 100 100 100 100 100 100 100 100 05 00 00 85 95 95 too 100 90 90 90 90 95 95 100 1 100 too 100 100 80 95 100 100 w SW s IVTtpb Pattern N> NW, l >rg W.SW 1 SE inTtpb Pattern Nw.N.sWw. I NE I SE 8 N.NE, NW W E, SE Ttpb IVA Pattern N, NW, I NE w, SW SE Sun Time N, NE. E, SE NW W sw Type V Pattern N, NW, W, sw E SE 30 30 35 50 90 105 110 85 8 60 60 60 60 60 90" 105" 115* , N, NE, NW \ E.SE SW S N, NE. NW W sw s ese .<6 Designation of Block Type II---Semi'Light Diffusing J-f III--Light Diffusing IV--Light Diffusing IVA--Light Diffusing V--Light Directing * Reduce by ! -lor 30 degNW;. itude only- Table 23* Approximate Corrections to Tables -14 and 22 for Devia^on^I from Indoor and Outdoor Design Temperature^ . .^r/f For each degree Ike design room temperature exceeds 80 F, subtract correction. * * design outdoor dry-bulb temperature exceeds 95 F, add correction. AppW:<i.'. ~--v ,, Table Hot Table 21. . GL.4SS Ttpb ! Correction Btu per (hr) *** Sinele Flat or Rolled Figured Glass Double Flat Glass and Glass Block Cooling Load 297 the corresponding Table 14 values.- ;>The total instantaneous heat gainJs the sum of the gain due to;transmitted solar,radiation sand; the gain ,by convection and radiation. . .. . - : , t; The values given in Tables 17 and,18 are based;upon-an.A.S.H.YiB. research paper2? to which the reader; is, directedfor; additional data. The values in Tables 17 and 18 may be used with fairiprecision for ptheripatr tems of ,similar transmittance and ;surfaee.:charactenstics. , : For. example, the data for hammered glass may;be usedifor glass haying shallow, closely- spaced ribs or for glass having small, closely-spaced circular indentations. Because some patterns have distinct,, orientation properties,;'mo attempt has been made to give values for non-vertical glass. ., Design Tables for Glass Block Walls . : , . ; . Tables 20 and 21 give.design values of. instantaneous rates 'of heat gain for sunlit walls of Type 1 pattern 8-in. hollow glass block for a solar declinationof 18 deg .(see.Tattle 19 for description .of block patterns). These tables are based upon the solar intensity values for a clear atmosphere as given in Table 4. For solar energy transmittance data the reader is referred to reference 21.. Table 20*presents values of transmitted direct and diffuse solar, radiation, while Table 21 gives values of instantaneous rates of heat gain by convection and radiation from the wall. The latter values are for.an.indoor temperature of 80 F.and a 95 F maximum dry-bulb temperature, as indicated in the table, and are based upon experimentallydetermined values of solar energy'Absorption and temperature difference between the two faces. Becausff the exact, dependence of the latter on weather conditions has not been determined;-' the Values of convection and radiation gain cannot be regarded as exact for the assumed design con ditions. Indoor and outdoor convection and radiation heat transfer data are the same as those used for common window glass. Table 23 gives cor rections to be applied for other design temperatures; V- To obtain transmitted direct and diffuse solar radiation for other types of 8-in. block, the Table 20 values are multiplied by the approximate per . centages given in Table-22. Note that corrections are the same for all latitudes, and that they-vary'only on the surfaces exposed to the direct sun. 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 waffs of some Patterns. ;- . __ Example W: Find the, total instantaneous ,heat gain through an east wall of -in. hollow glass block of Type V pattern at 8 a.m. and SO deg north latitude. The design temperatures are 80 F indoors and1 95 F maximum outdoor dry-bulb, clear awnosphere. ... . .. , Station: The gain due to transmitted solar radiation is found from Table 20 yfPf I pattern. The'factor for Type V is found from Table 22. . The convection dd radiation gain is found from Table 21 (note, the fpotnote). . The total instantaneous heat gain is, from Equation 2a, ? = 86 X 0.65 + 26 X 1.4 = 92.3 Btu per (hr)(sq ft). Effect of Deviations from Design Conditions - - b indoor temperature differs from 80 F,:, or the design outdoor dryuib temperature differs from195 F, corrections can be made to the convec'n and radiation gain values for flat glass, rolled figured glass, and glass Tg according to the schedule in Table 23. <: : be effect of the humid industrial type atmosphere is to cause a con- 298 CHAPTER 13 1954 Guide f? siderable reduction in heat gain, if all factors except solar intensity remain the same. Reference 22 gives heat gain values for four orientations at 40 i 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--Design Tables The effects and possibilities of shading should be carefully investigated whenever the heat gain from glass is a large portion of the cooling load. Vertical glass, which is not mounted in the plane of the building surface, ' is.partially shaded by the setback. If a vertical window of height l and. width w be set back from the plane of the building a distance s, the fraction of the total area of the window' which receives direct solar radiation is: : G, = 1 r, tan 0 . r,jy tan 0 tan-y :-------------- IV tan y -|---------------------------- cos y cos y (5) where r, = s/l, r, = s/w, 0 = solar altitude, and y is the wall solar azimuth (see Fig. 1). Values of /3 and y for various latitudes and August 1 are given in Table' 6. Special cases not covered by the tabulated data may be solved analy.-: tically;11 however, the design- conditions chosen will yield a satisfactory> approximation if used without correction for any time during the summer,-' period. . Example 11Estimate the total instantaneous rate of heat gain for a west win dow 3 ft wide by 5 ft high, with a setback of 6 in., for August 1 and 40 deg north;, latitude at 3:00 pm (sun time). * -T- Solution: From Table 13, the instaneous rate of heat gain, due to transmitted;: direct and diffuse solar radiation, is 180 Btu per hr. From Table 6,0 is 45.5 deg smi y is 16 deg. From Equation 5, the fraction of the total window area that is receiving- direct solar radiation is: -' - . >"5/( Gi = l 0.1 tan 45.5 ,, , 0.0167 tan 45A tan 16 ------ ---- -- 0.187 tan 16 + ----------------- ------------- - cos 16 cos 16 = 1 - 0.106 - 0.048 + 0.005 = 0.851 In this instance the convection and radiation heat gain is due principally; to temperature difference, so that shading has but a small effect on that: portion of the absorbed radiation. Hence, the factor 0.851 is appW; only to the Table 13 value. Note also a small error results from the fact; that the diffuse radiation is not shaded to the same extent as the direct- radiation. The total instantaneous heat gain therefore is: ^ 9 = 3 X 5 (0.851 X 180 + 26) = 2690 Btu per (hr)(sq ft) JV A window such as the one used in Example 11 would customarily be prfe; vided with an additional shading means for use particularly when direct!/: sunlit. Conventional shading devices include awnings, shades, and screen*-; of various types. Recent experimental and analytical work conducted at the A.S.H.Yt8f Research Laboratory26 as well as earlier experimental work,24- 28 and othtfy research22 to determine the effectiveness of various types of window shau?fe Cooling Load 299 have been used as the basis for the recommended ratios in column 3 of Table 24. A study of absorptivity of the shade to solar radiation and heat transfer from the shade to the outdoors and indoors, -was used to determine these ratios. There are a number of variables affecting these ratios such as color, fit, solar altitude, and angle of incidence of the solar radiation. These values, Table 24. Effect of Shading Upon Instantaneous Solar Heat Gain Through Single Thickness of Common Window Glass Type op Shading Canvas awning sides opes ' 14Canvas awning top and sides tight against building Inside roller shade, fully drawn Inside roller shade, fully drawn* Inside roller shade, fully drawn* Inside roller shade, half drawn* Inside roller shade, half drawn* Inside roller shade, half drawn* Inside Venetian blind, slats.setjit,45 deg*' Inside Venetian blind, slats set aC45 degb I iside Venetian blind, slate set at 45 deg -aside Venetian blind, slats set at 45 degb Outside Venetian blind, slats set at 45 deg" Outside Venetian blind, slats set at 45 deg"- c extended as awning fully covering window Outside Venetian blind, slats set at 45 deg, extended as-awning covering of window Finish on Side Exposed to Sun Dark or medium Dark or medium White, cream Medium Dark White, cream Medium Dark White, cream Diffuse reflecting aluminum metal Medium Dark White, cream White, cream White, cream Fracttion of Gain Through Unshaded ' Window 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 Darkd- < Green Outside shading screen solar altitude 20 deg tint*- * Outside shading screen solar altitude 30 deg 0.52 0.46 Outside shading screen solar altitude, above 40 deg 0.40 0.35 0.25 0.24 . Roller shades are assumed to be opaque. Some white shades may transmit conside0r.a1b5le solar0r.2a2dia tion. For white translucent shades fully drawn use 0.55 and for half drawn use 0.77. ^' b Venetian blinds are fully drawn and cover window. It is assumed that the occupant will adjust slats to prevent direct rays from passing between slats. If slats are fully closed (slats set at 90 deg.) use same 'actors as used for roller shade fully drawn. Commercial shade with wide slats. The sun may shine on window through sides of shade. Estimate Commeprcoiartliosnhaodfeg, lbarsosnazse.unsMheatdael ds.lats 0.05 inches wid e 17 per i>nch and set at 17 deg ang.le w.ith hori zontal. At solar altitudes below 40 deg some direct solar rays are allowed to pass between slats, and this becomes progressively greater at low solar altitudes. ' . Commercial aluminum shade. Slate 0.057 inches wide, 17.6 per inch, set at 17 deg angle with horizontal. At solar altitudes below 40 deg some direct solar rays are allowed to pass between slats and this amount be- C0Qje Progressively greater at low solar altitude. . . from first paper in Reference 9. therefore, must be considered as approximate, only, and will have to be used with considerable judgment. An inside shade is effective to the ex tent 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. INSTANTANEOUS HEAT GAINS VS. INSTANTANEOUS COOLING LOADS jjjJ'j16 difference between instantaneous heat gain and instantaneous cool- & oad has been mentioned previously; its practical importance is suffi- f3do CHAPTER 13 1954 Guide ;cidnt to Warrant fiirther consideration.' Fig. 4 offers a simplified schematic 'illustration'showing how the radiatiue part of the instantaneous heat gain `isfirst absorbed bysolidobjects, and is hot encountered by the conditioning equipment as a cooling load until some later time, When it finally appears in' the' air stream entering the 'equipinen;i 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 minutes 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 asthe thermal capacitance of the objects and materials involved is increased. Constituents of the total instantaneous heat gain which have appreciable : radiation components include those due to glass areas, exposed walls and roofs, lighting, appliances, and people. No comprehensive data: are presently available-for use in design load estimates to evaluate the interior load-lag effect, but several investigators^i4, 28, a. so ]jave made a' study of the problem and have-presented many . useful data. Tables ,9,10, .13,14,18,20, and 21 are all based on instantane- . ous rates of heat transfer. Hence, practical judgment and experience offerI the only basis of procedure. Until the needed data become available, it is recommended that the non-continuous load be averaged over two or three hours during the time of maximum 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! outside 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 adjacent to another space in whichrt ` different temperature prevails, the transfer of heat through the separating, structural section must be considered. Calculations are made according, to the relation: . q= (7iAi(fb -- <i) Btu per hour. . - - ... (6) where Ui = coefficient of overall heat transfer between the adjacent and the concfe tioned space, Btu per (hour) (square foot) (Fahrenheit degree). Y.f A i = area of separating section concerned, square feet. ' b, = air temperature in adjacent space, Fahrenheit degrees.' t , = air. temperature in conditioned space, Fahrenheit degrees. ' iiK -.e-l Magnitudes of C7i may be obtained from Chapter 9: The-temperature fb may have any value over a considerable range, according to conditio?^ in the adjacent space. The temperature in a kitchen or boiler room may K? as much as 15 to .50 deg above the outdoor air .temperature. ,It is recoffl*' mended'that actual temperatures be measured in adjoining spaces wherever, practicable. Where nothing is known, except that the adjacent space is. conventional.construction and contains no heat sources,-it is recommend11, that the difference (A -- fi) he taken as the difference between the pjjy;- door air and conditioned-space design dry-bulb temperatures minus 5 deg- Cooling Load . 301 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 latter conditions, -the heat gain; through, the partition will be periodic in nature, and the value, of a shaded 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 OUTSIDE AIR, VENTILATION AND INFILTRATION Ventilation. Data for determining the necessary ventilation' rate have been presented previously in- this-, chapter, i Ventilation required-is pri marily dependent upon the number-of,occupants and upon the materials and apparatus within the space -which may - give, off odors.: For spaces having ceding heights 10 ft or,less, the total requirement should-be checked against the volume, and in no-case should the ventilation air rate-be less Fig. 4. Origin of the Difference Between-the. Magnitudes of the InstAn taneous Heat Gain , and Instantaneous Cooling Load ; The radiation absorbed by the interior furnishings and structure reaches-the conditioning equipment after a considerable delay in time. .. ,, . . . .. than one air change per hour. In spaces having ceilings higher than 10 ft where the occupant load is iow, 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 ventilation, because on still days there will be little or no infiltration. . Infiltration. The principles of infiltration calculations have been dis cussed in Chapters 11 and 12, with emphasis on the heating season. For the cooling season, infiltration calculations 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 the total perimeter of the movable or ventilating sections. In calculating window infiltration for an entire structure, it is not necessary to consider t-he total crack length on all sides of the building, for the wind would not act simultaneously on all sides at once. In no case, however, should less than half of the total crack length be figured. A knowledge of the pre vailing wind direction will aid judgment in this consideration. Cooling-load infiltration for doors51 may be obtained from Table 3, Chapter 11. For conditions other than those covered, the notes appended j-o the table will provide a basis for estimates.1 The tabulated data may also oe used as the basis of estimates for interior doors between an air-condi- ned and a non-air-conditioned space. , ... Infiltration load must be included whenever the new air introduced 'Ml 302 CHAPTER 13 1954 Guide Jg through the system is not sufficient to maintain excess pressure within the enclosure to prevent the infiltration. Whenever economically feasible, it is f desirable to introduce sufficient outdoor air through the air-conditioning ic equipment to maintain a constant outward escape of air, and thus eliminate the infiltration portion of the load. The pressure maintained must, of course, be sufficient to overcome wind pressure through cracks and door , openings. When this condition prevails it is not necessary to include any v 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 Outside Air Load. Many cooling coil manufacturers publish tables i! 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 cal culate the mixed air condition entering the coil, and determine from the tables what coil and air velocity will produce the desired leaving air con- ditions as required for the space to be conditioned. When cooling coils i 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 i section on Apparatus Dew-Point. To determine the design cooling load caused by the introduction of out ' side air, the maximum rate of outside-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 ratet? Once this design quantity is established, and with the design indoor and | outdoor air states known, the cooling load may be computed. There are several methods in use; the more accurate of these require rather detailed 9 calculations. Refer to Chapter 3, and also section on Apparatus Dew-Point^ in this chapter. The following equations are considered to be of sufficients^ precision for use at usual design conditions, as their accuracy is within l|j percent. fil Sensible Load q, = Q X 60 X 0.244 X 0.075 ^1 0.62 / = OX 1.08 (to -- ti), Btu per hour I (Du- Latent Load q. = Q X 60 X 0.075 X 1076 (W,, - Wd = Q X 4840 (Wo -- Wi), Btu per hour i Total Load ?, = 9* + 9* where . Q = rate of entry of outside air, cubic feet per minute. to = outdoor dry-bulb temperature, Fahrenheit. L = indoor dry-bulb temperature, Fahrenheit. Wo = outdoor humidity ratio, pounds moisture per pound of dry air. W, = indoor humidity ratio, pounds moisture per pouBd of dry air. 0.075 = standard air density, pounds per cubic foot. V < 'hMi If 01 -is Sfi Cooling Load 303 0.244 = a constant approximating the specific heat of dry air corrected formoisture Btu per (pound) (Fahrenheit degree). 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 ventilation air into two parts: one por tion which does not contact the coil surfaces (i.e. bypasses the coil) in passing through the coil and thus becomes a part of the 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 ex plained in the literature by Ashley,31 is believed to be very easy and ac curate to use. Similar equations, therefore, can be written: Space Sensible Ventilation Load, q.i = Q X 1.08(fo - <0 X b Space Latent Ventilation Load, 9,,i = Q X 4840(Wo - WO X b Remaining Sensible Ventilation Load, . ? = C X 1.08(4, - h)(l - h) Remaining Latent-Ventilation Load, 9x = Q X 4840(Wo - Wi)(l - b) 9t = 9*i - 9 9xi 9e* where . (10) (11) (12) . (13) (14) b = fraction of air passing through coil which does not contact surfaces, coil by pass 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 conformity. HOW OUTSIDE AIR LOAD AFFECTS ROOM LOAD Actually, the outdoor air used for ventilation would pass through the conditioning equipment, and be cooled and dehumidified to a lower tem perature 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 the outdoor and indoor air conditions. One important purpose of the cooling load estimate is to determine the conditions and quantity of air supplied to the space. All the various sen sible and latent heat loads within the space must be included. Infiltration nust be included in the space load since this air enters the doors and win nows, and its heat and moisture load must be offset by the introduction of cooler, dryer air to the space. However, since ventilation air is taken through the conditioning equipment and cooled, this portion does not be come a part of the space load, except a small portion which passes through the coil untreated. To determine the total load on the refrigeration ma chine, the remaining ventilation air load must be included in the grand total load. .. n 1 "door dIeSs:igFnocroonudtidtiooonrs design conditions of 95 F of 80 F dry-bulb and 67 F dry-bulb and 75 F wet-bulb, wet-bulb, and for the supply owt CHAPTER 13 of outdoor air at the rate of 1000 cfm and the exhaust of room air at the corresponding rate, calculate the total, sensible and latent heat gains. , Solution: Substituting in Equation 7: ?, -- 1000 X i .08 (05 -- ) -- 10,200 Btu per hr. From psychrqmetrie data,lfo .= 0.01413, ITi = 0,01122. . , ...... . Substit?u.t:in=g i1n0K0q0u.Xa/t4io84n0s 8(0a.n0d1491: 3.- 0.0, 1.1.2.2) = 14. ,100 Btu per hr. gi q, + ft s= 30,300 Btu. ' : ' ` ' 25.Table Rates of Heat Gain from Occupants of Conditioned Spaces* Degree o* Activity Typical Application Latent Heat Bttj/Hb Seated at Rest........................... . Seated, Very Light Work............. Moderately Active Office Work. Standing, Light Work; or Walking Slowly.. -.................. ... Theater-Matinee----Theater-Evening----- Offices, Hotels,- ; Apartments. ------.Offices, Hotels,- ' Apartments.... : Department Store,- Retail Store.;,: .-i Dime Store.............. Walking; Seated....... ....... ......... Standing; Walking Slowly......... Bank................. Restaurant... Sedentary Work........................... Factory............ Light Bench Work....... ................ Dance Hall MWoadlkeirnagte3Dmapnhci;ng..:.........1......;.;......Moderately Heavy Work.................. Bowling*1................................................ FBFBaoaocwwct.tlo.loiinnrrygg.y; .,AA......ll..ll..ee-.....yy..... Hrieewaa*vvuNyynaWWgte-o:.o.r.rT.kk.a....b.....u.....l..a....t..e.....d...8.v..a..l.u..e...s..a...r.e...b..a...sjei*dFaoaccnttoo80rryyF.....f...r...o.....m.........d..r..y..T..b.^ulb temperature. For, ,78.F room dry-bulb, total heat remains the same, but the sensible heat values should be increased by approximately 10 perceisV,,-:- ind*thAedjluastteendttohteaal tkevaatlugeasin'deiscrbeaasseeddoanccnoorrdminagl lpye::rcJe!nit,age:.<o-f-.imen, women, an,dchild- ren/for.the application, . isted, with the postulate that the gain from an adult female is 85 percent of that lor an adult male, and the gun from a child is 75 percent of that for an adult male. '. Adjusted total.heat value lorsedenUiryuork, restaurant, includes 60 Btu per hour for food per individualJ-1 (30 Btu sensible and 30 Btu latent).f'- ? .) ' ' s ' ` : , C ' *5.^ d For howling figure one person per alley actually bowling, and all others aa sitting (400 Btu per hour}.\V-', sr standing (550 Btu per hoyr).i . : . . 1 ; . .; : . , . . -. ... -- . j fSs. baepipnlgicsautinodnesrtbdeif^feerseenntssibtalei.easnd latent heat gains become a large fraction yv*. the total loadi;:. Appreciable' variations ` iii' heat-emission1 rates: must? 'bev recognized according to the age'arid Sex/dfjtbe individual;-state of .aritivifflsj environmental'influences, and duration :of bccupandy1 (since f<jr:!sh^' occupancy the extra heat and moisture brought in'by people'may beffjky sigWnihficileanCt fhaacptoter)r'.'6 shou"ld be ref)e;rriel/d to'for" detailed information, Tabfe^ 25 in this chapter summarizes practical data representing conditions co^g[j monly encountered. , . . .' ; . , , 7(^:1 Lighting. . In general,, the instantaneous, rate of heat-gain from.elec^M lighting32 may be calculated from the following relation: "V-- -- , ftotal light v f use (special allow- ^ 341-Btu per hr. 4" ~ (wattage * (factor lance factor Cooling Load 305 The total light wattage is obtained from the ratings of all fixtures installed, both for general illumination and for display use. The use factor is the ratio ofthe wattage in use, for the conditions under which the load estimate is being made, to the total installed wattage. For commercial appli cations such as stores, the use factor would be unity. The special allowance factor is introduced tq care for fluorescent 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 iadost. For ventilated fixtures, recessed fixtures, and the like, manufacturers' or other data*3 must be sought to establish the fraction of the total wattage which may be expected 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: /Horsepower Rating) / Load V _ ,, , Sen = I ' .--------- ) X ( ) X 2544, Btu per hr. \ Motor Efficiency / \Factor/ ,, (16) It is assumed that both the motor and the driven equipment are within the conditioned space. If- the motor is without the space, then do not divide by the motor efficiency in Equation 16. The load factor is merely the fraction of the rated load which is being delivered under the conditions of the cooling-load estimate. Motor efficiencies may be approximated as follows: about 50 to 60 percent at f 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 the heat gain from all appliances, electrical, gas, or steam. Table 26 presents recommended data.34 Note that the maintaining rate in Table 26 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 up a lower limit to the heat gain to a room from the appliance when in operation. Experienced judgment must.be used in the application of data given in Table 26. Consideration must be given to the heat contributed by appli ances 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 appliances are hooded allowing part of the heat to escape through a stack. There are ho generally accepted data available on the effects of venting and shielding heating 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 condi tioned. The same effectiveness of the hood should be figured for both atent and sensible heat. . load from moisture transfer through permeable 1 BUILDING MATERIALS The diffusion of moisture through all common building materials is a rural phenomenon which is always present to a greater or lesser degree. 'The permeability and permeance values for various building materials T a b l e 26. R a t e o f H e a t G a in F r o m A p p l ia n c e s W IT H O U T HOODS" ' Cooling Load Cooling Load 309 are given in Table 2 of Chapter 10, together with, an explanation1 of moisr ture transmission through these materials: . In the: usual comfort'air-conditioning application* it is, common prac tice to neglect moisture transfer through walls, for the actual rate is quite small alid the corresponding latent-heat load is hardly significant. Socalled vapor barriers are frequently employedin modem construction for the purpose of keeping moisture transfer to a minimum, and reducing the deteriorating and insulation-destroying effects of moisture. . . Industrial jobs, oil the1 other hand, frequently call for a low moisture content to be maintained in a conditioned space. Here the matter of moisture transfer cannot be neglected; indeed, it is quite possible-to have the latent-heat load accompanying this transfer be of greater magnitude than any other latent-heat load.1 The equation for computing this load is: ( j)=~ x U*r Prer:) x kTM, Btu per ^ (sq ft) \A J 7000 \Difference, In. Hg'/ (i7) where : M = permeance of the specimen in perms, or grains per (square foot) (hour) (inch of mercury vapor pressure difference). 1 7000 = grains per pound. The factor 1076 is defined in list of symbols at Equation; 9. (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 vapor proof. All openings in moisture proof construction must be equipped with special gaskets to pre vent entrance of moisture. When moisture transfer contributes an appreciable part of the latentheat 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 dehumid ifying 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 gains jfrom exposed piping, ducts, work done by circulating fan, and unforeseen con tingencies. Where sufficient data are available, these various heat gains may be estimated individually. In the majority of cases, however, common Practice is to lump1 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. com pensate for miscellaneous effects. No rules can be given for this proce dure, as experience in air conditioning is indispensable for application of suitable safety factors. APPARATUS DEW-POINT AND REQUIRED AIR QUANTITY THROUGH CONDITIONING EQUIPMENT of^h rdinary practice, with commercial apparatus, complete saturation ,e air is seldom obtained. Four-row finned cooling coils contact ap9 oximately 80 percent of the air, whereas six-row finned coils contact PProximately 95 percent of the air. In spray type dehumidifiers of good SJ il310 CHAPTER 13 1954 Guide design the air leaves the dehumidifier at 1 to 2 deg higher wet-bulb tem perature than the spray water leaving the dehumidifier, and the difference between the dry-bulb and wet-bulb temperatures leaving the'dehumidifier may be as low as 1 deg. A spray type dehumidifier having sufficient length of spray chamber and density of spray, together with proper arrangement of nozzles, may approach saturation very closely. As explained in Chapter 3, and shown in Fig. 5, the slope of the line on the psychrometric chart connecting the room condition with the apparatus dew-point on the saturation line, determines the ratio of sensible heat absorbing capacity to the moisture absorbing capacity of the supply air. Therefore the room condition can be maintained as long as the supply air temperature lies on this line, but a greater volume of supply air must be used to satisfy the room load if the cooling coil does not contact 100 per Fig. 5. Apparatus Dew-Point Shown on A.S.H.V.E. Psychbometric Chart ,=j` '.[ cent of the air. For a given room load, the same apparatus dew-poiiit'Sf will be required whether the cooling appliance contacts all the air or orilyjj* part of the air. ' ! .. From the point of view of satisfying the given cooling load require-^ ments, the air passing through the apparatus without being cooled belowjji the dew-point temperature produces two effects: 1. The air quantity which must be passed throug'h the 'dehumidifier muBt be iij;|p creased. Thus, if 20 percent of the air passing is contacted, then (20-e 80) X 100 25 percent more air must be used than would be necessary if all of it were contacted^' 2. Passing untreated air may change the room cooling load, which in turn change the enthalpy-humidity difference ratio (sometimes called the sensible factor). If return air only is passed through the dehumidifier or if room air onlyi.^ by passed, the room load will not change, but if some outside air is passed throug%^ the room sensible heat gain and room latent heat gain will be changed due to-the^| addition of untreated outside air, which changes the enthalpy-humidity differen^g ratio. When a load calculation is made, it is necessary to know the percentage air affected in the dehumidifier, and calculation must be made accordingly. aS ... . .^1 If the ventilation air is drawn through the dehumidifier before it go<p| into the room, only that portion of the air not saturated must be includ|8'3 - oi8 Cooling Load 311 in the room load for the purpose of determining the apparatus dew-point and supply air quantity. It should be noted when evaluating the load added by untreated outside air that the temperature difference between room air and outside air, and the moisture content difference between room air and outside air, should be used, rather than the difference between outside 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. The procedure for determining the required air quantity is based upon the thermodynamic principles of Chapter 3 and the use of the A.S.H.V.E. psychrometric chart. Readers are advised to review these principles, paying particular attention to the illustrative examples of cooling load calculations. Calculation of the cooling load for a conditioned space is equivalent to making, for the space, a heat balance in which all heat, moisture, and infil tration are treated as directly entering the space. As explained in the section, Load from. Outside Air, Ventilation, and Infiltration, the outside air load normally does not become a part of the space load, because heat and moisture are removed in the air conditioner before this air gets into the conditioned space. The desired conditions are maintained by considering a certain quantity-of air to be withdrawn from the space, passed through the conditioning equipment, and returned to the space with such a tem perature and humidity ratio that its net effect will be to counterbalance or remove the given entering amounts of heat and water vapor. This quan tity of indoor air, which is considered to 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: spa1c.e.Determine the total sensible and latent heat loads in Btu per hour for the 2. Compute the quantity called the enthalpy-humidity difference ratio (also referred to as heat-moisture ratio) of the room load, ~ . Use the equation; where hi -- h, (Space sensible load + space latent load) Wt -- W% ~ Space latent load/1076 11 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. = humidity ratio of moist air supplied to the space, pounds of vapor per pound of dry air. -- humidity ratio of moist air at room design conditions, pounds of vapor per pound of dry air. Note that the ratio (space latent load/1076) is the equivalent of the required rate ? water vapor removal in pounds per hour. If the rate of water removed is known, i may he used directly in Equation 18. , * T*raw a line through the reference point on the A.S.H.V.E. psychrometric ar^ aud the value of (hi -- h,)/(fVi -- W,) determined above. Draw a second line rn i th state point of the room air (design wet-bulb and dry-bulb temperatures) P railel to this line. This is the condition line for the process. tion *^ie. temperature where the condition line from step 3 intersects the saturahne. This is called the apparatus dew-point. See Fig. 5 Note that instead of using this graphical method the left hand sid- 312 CHAPTER 13 1954 Guide of Equation. 18 may be solved by :trial and error by substituting values of A, and Wi corresponding to assumed apparatus dew-point temperatures. 5. Compute the required air quantityfrom therelation (SpSCS SOn9>tlp ]nfi/j) ' . : (la) ................ The magnitude of Q is substantially the quantity, cfm, of cooled and 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 00923Y - - ' `; .. 1----- og2~ ) ~ L08, assuming an average supply airdew-point of-55 F; b 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 = humidityratio of; b air. at 55 F dew-point, and 0.62 = ratio of density of water vapor to dry air at same f. temperature And pressure,. Refer to Chapter 36 for coil selection. - Note that the product [(space dry-bulb) -- (apparatus dew-point)] X (coil by- ~t gass factor) is equal to the dryrbulb range through which the conditioned air is cooled / ;. ence, 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, provided that the coil by-pass factor is specified accordingly on the proper basis: : :. MINIMUM ENTERING AIR TEMPERATURE '-g Due consideration must, be given to the temperature of the air entering) jg the conditioned space in order to prevent objectionable drafts. With ceil-vy' mg type diffusers or wali grilles with a high aspect ratio (see Chapter 31),.gig many engineers consider 20 deg as the maximum difference for good design .gg under average conditions. This difference can only be exceeded with exia-g? ' tremely high ceiling outlets or wall grilles. Thus, if 80`F dry-bulb is to be jjg maintained in a space with average ceiling height, the.minimum delivered*. - air temperature would be limited to about 60 F dry-bulb temperature. If/'.,-, the latent heat load is relatively high, it is often necessary to circulate moreggs air with a higher delivered dry-bulb temperature in order to produce a *>f thermodynamic balance. If the dry-bulb temperature of the air supplied,,,/ to the space is known, the required air quantity can be calcuated fromgg the formula, -if; Cr. = 1.08 u , - Q (20) or the supply temperature t, can be determined as follows, t, -- 1.08 X Qn (21)'; ' EXAMPLE--COOLING LOAD CALCULATION utjC' An effective means of summarizing the calculation procedure will be the;*, use of an illustrative example. While condensed calculation forms arepi ccoommmmoonnllyy employed empioyeu for iui work of this nature, ________________ an outline will be used Keregsr in- o--rdJe--r to facilitate oevxnplanaftnorvy ocomments:; - Example IS: A one-story office building Fig. 6 is located in an eastern state near . deg latitude. The adjoining buildings on the north and west are not conditioned)^.. Cooling Load '2>13 and the air temperature within.them is known to be substantially equal'to the outdoor air temperature at any time of the day. . . . a- -- t. .s....... .. South wall construction: 8 in. concrete block, 4 in. brick veneer, J in. plaster on walls. (Table 9, Chapter 9, No. 92B, U = 0.41.) : East wall and outside,north.wal! construction :S in: concrete block. paintedwhite, 4 in. plaster on walls., (Table 8, Chapter 9, No.82ByU = 0.52.) i ' ' ; i-r-mui >: West wall and adjoining north party Wall'construction: 13 in. solid brick, no plaster: . : M'' ''' .' J/' V' 1 -L:+*+-L U ' 1.65, ,5 T.65 or, : C/ = 0.263: Use U = 0.26. ; Roof construction:1^! in. flat roof deck Of 2 inV gypsuin'fiber concrete'oh.gypsum board surfaced with built-up roofing. (Table 11',' [/'='0.34 for summer.) " g - '. g Floor construction: 4 in. concrete on ground. Window: 3 ft x 5 ft, non-opening type, with medium colored Venetian blinds,for windows on south wall. Approximately 4 ih'.'revea.l oh all windows. " Fig. 6. Plan op One-Stout Office Building Front doors: Two 2 ft-6 in. x 7 ft (glass panels). ............ Side doors: Two 2 ft-6 in. x 7 ft (| glass panels). Rear doors: Two 2 ft-6 in. x 7 ft (wood panels). / ,. < Outside design conditions: Maximum dry-bulb 95 F,,wet-bulb 78 F; Wo = 0.0169 lbs vapor per lb dry air; hi = 41.38 Btu per'lb dry-air. , ' ` g.;g g- ..... . . . Indoor design conditions': Drjribulb 80 F, wet-bulb 65 F; Wi .= 0.0098 lb vapor per lb dry air; Ai = 29.95 Btu,per lb dry air. g . , 1 Occupancy: 85 office workers. Lights: 12,000 watts, fluorescent; 4000 watts tungsten. Pan motor; 7J hp. . ,' 1 - Assume that cooling coil has a by-pass factor of 0.15, t.e., that 15 percent of the air passes through the coil without contacting the coil surface. ' Conditioning equipment to be located in adjoining structure to north. , ,, Find: Total, sensiblegand latent maximum cooling loads and required air quantity rngh conditioning equipment. Tnt}ut*on: From Table 3, the recommended ventilation rate is 15 cfm per.person, otal necessary = 85 X 15 = 1275 cfm or 76,500 eu.'ft',per hr. . . CHAPTER 13 . As the room volume is 40,000 cu ft, the air changes perhour 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 con tribution 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 medium weight construction is 54 deg at 4:00 p.m., and 53 deg at 3:00 p.m. Examination of Table 13 (40 deg N Latitude) shows that solar heat gain through glass 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 occurs at approximately 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 necessary 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) mav 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 p.m. for a light colored wall (interpolating between 2:00 and 4:00 p.m.). Likewise, the tem perature differential 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 the 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, Table 10, No. 5A. The outdoor temperature at 3:00 p.m. is 95 F. Neglect time lag and any decrement factor. The temperature differential is (tP -- L) -- 95 -- 80 = 15 deg. The tabula tion of the preceding values at 3:00 p.m. is given in the following table: Section Net Abba Sq Ft Temperature Differential F Deg Heat Transmission Coefficient (U) Heat Flow Rate per Hour Btu Roof South Wall _ East Wall North Exposed Wall West & North Party Wall Door in North Wall 4000 405* 765* 170* 1065* 35 53 0.34 6 0.41 11 0.52 3 0.52 2 0.26 15 - 0.59 -------------------------------------------------- . ,, ____________ Calculated from gross wall area, less windows and doors. 72,000 995 4,380 265 550 310 78,500 Heat Gain Through Glass Areas In computing the load for 3:00 p.m., only the south windows and doors will be-! exposed to direct sunlight. Tables 13 and 14 will give the total heat gain from the glass areas. The window reveals will &hade the south windows; the fraction of the*, window area receiving direct radiation is obtained from Equation 5 by substituting - values as follows: .. , n = s/l = 4/60; r, =* 4/36; 0 = 45.5 deg, tan j3 = 1.02 7 ** 74 deg, tan y -- 3.487, cos 7 = 0,276 ! O' - - A.(S) - + (e) (I) ni - , The south doors will be considered entirely sunlit. The outdoor air temperaturtr' is 95 F at 3:00 p.m. From Table 24 the inside Venetian blind factor is 0.65. The*v, Cooling Load 315 instantaneous heat gains due to transmitted direct and diffuse solar radiation, and from convection and radiation gain, are found in Tables 13 and 14 as listed below for the south facing doors and windows, the north facing windows and the J 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 to + ctjjfao is found to be 98.2 for a = 0.7 and fw = 4.0. From Fig. 3, q = 27.0 Btu per (hr)(sq ft). These heat gains are itemized in the following table (note that there are no corrections to Table 14 .values .since table is based on 80 F temperature, but Fig. 3 is based on 75 F room temperature). Location South Windows South Doors East Doors/Glass VT (Wood North Windows Total Area Sq Ft 60 35 18 18 30 Frac tion Sunlit 0.462 1.00 Shade Factor 0.65 Trans Solar Gain Btu/ (hr) (sq ft) CORR CoNV and Rad Gain FROM 75F TO 80F Btu/ Indoor (hr) Temper (sq ft) ature Btu/(hr) (sq ft) Total Gain Btu/ (hr) (sq ft) Total Gain Btu/hb 13 42 14 15 19 19 ,1 32 61 17 31 27 22 17 . 32 1920 2135 560 395 960 ' 5970 , __________--_ v..v muvuuuaucuua 1 auiauon neat gain 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. j' r uiwn Since the necessary ventilation rate 1275 cfm is greater than one air change per hour, it will be satisfactory for determining the 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. The design rate of entry of outside air is then: Q = 1275 4- 67 = 1342 cfm. ... sensiDie, latent and total loads are determined from Equations 7, 8, and 9, respectively, at 3:00 p.m. (Table 8) to = 95, U = 80, IT. = 0.0169, W, = 0.0098. A1 the air entering the room as infiltration becomes a part of the space load. Infiltration (see Equations 7, 8, and 9): , ?* = 67 X 1.08 (95- 80) = 1085 Btuh, sensible. 3. = 67 X 4840 (0.0169-0.0098) = 2300 Btuh, latent. 3* = ?. + ?. = 1085 + 2300 = 3385 Btuh, total. I ^'enh/ah*ori Air Taken through Cooling Unit Which Becomes a Part of the Spac* 0a" (see Equations 10 and 11): 3.i = 1275 X 1 08 (95-80) (0.15) = 3,100 Btuh, sensible. 3.i = 1275 X 4840 (0.0169-0.0098) (0.15) = 6,570 Btuh, latent. :y,ii - . Ventilation Air Takenthrough Cooling Unit Which Does Not'Become d Part of the :(h Space Load (see Equations 12 and 13): 1 ' 1 i. ......... = 1275 X'1.08 (95-80) (1-0.15) = 17,600 Btuh, sensible. ' - 1275 X 4840 (0.0169-0.0098) (1-0.15) = 37/230 Btuh, latent, <7t =. 9.1 + 9.1 + g.1 +.g = 3100 + 17600+.6570 + 37230 = 64/500 Btuh total. Heat Gain from Sources within the'Conditioned Space: .. For the occupants, use the data of Table 25 for moderately active office work. Sensible heat gain = 85 X 200 = 17,000 Btu per hr. Latent heat gain = 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 * aliowanee factor of 1.20 for the fluorescents and of unity for the tungsten globes. A , , g.i = (12,000 X 1.20 + 4000) X 3.41 = 62,700 Btu per hr. *'fr 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. .V g. = 7.5 X 2544 = 19,100 Btu per hr. f> Moisture Permeation, Miscellaneous Allowance, and the Load-Lag Estimate: Moisture permeation will be negligible, Bince this is a comfort, job with a good+ building construction. , , ... .. , . . ... . There would be some heat gain in .the ductwork; but this would not be great be- + cause of the short run involved. . Practical judgment for this job would suggest thatg 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 important part, of the total heat gain,/> it is advisable to be conservative in recognizing the effect of the large, flat, hot roof-.i on the comfort sensations of the occupants. Radiation from the relatively low ceiling, .); augmented by heat absorption from the lighting,fixtures; would produce a sensation k of warmth in excess of the nominal effective temperature (see Chapter 6) estab. / lished 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: -o':; The total loads are summarized in the following table: Summary or Total Loads--Example 13 Load Component - Sensible Btu/hr Latent Btu/hr .. Ail walls, roof and doors...................................... Glass areas......................................................... Infiltration 67 cfm.........................: ...................... Ventilation Air (1275 cfm X 0:15)..................... Occupants.................................................................. Lighting...................................................................... Motor, fan................................................................. Space Load.......................................... Ventilation 1275 cfm X (1-0.15)............ .. Totals...................................................................... .... Grand Total Sensible and Latent..................... 78,500 6,030 1,085 3,100 17,000 62,700 19,100 187,515 ' 17,600 205,115 . .... 2,300 6,570 21,250 .... -- 30,120 ' ''C "0., ' .V /; 37,230 67,350 - 272,465 (,) Compute the enthalpy difference ratio from Equation 18 . hi - K (187,455 + 30,120) X 1076 = 7770. Wi-W. 30,120 Cooling Load ratus dew-po-i-n--t--a-s-.5..3..9tiF.ip. sycnrometric+hart Chaptci.o, aee Compute the effective air quantity (Equation 19). Then,. Qr, 1-08 (80 -- 53.9) x 0.85 - 73 cfin. (Refer to Chapter 36 for coil selection.) ': ' From note under Equation 19 the dry-bulb range will be (80 "+ 53.9) X 0:85 = 22.5 deg, and the dry-bulb temperature of air leaving the.coil will be 80 -- 22.2 = 57.8 F. The dry-bulb temperature leaving, the .fan (including.the. heat, supplied by the fan motor), or delivered into the room, will be (from Equation 16): " ,, 187,455 -7-1893,01-00 " 80 - 19 9' = 601 R" ' ' , , I, With good distribution and'diffusion, this temperature should not produce objec tionable drafts. The various calculations for .the sensible, latent, and total heat loads for Example 13 may be summarized,as follows:,; ,. - Outdoor Conditions;-. SOpuatcdeooConditions................ Difference. .. Example 13: Summary .95 DB . S0X>B - 78; WB. 65 WB : 0.0169 Humidity Ratio , 0.0098 Humidity Ratio Sensible Load Transmission Roof 4000 sq ft X 53 X 0.34 =........... .. S. Wall 405 sq ft X 6" X 0.41 =..................... E. Wall 765 sq ft X 11 X 0.52 =............. N. Wall Ex. 170 sq ft X 3 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 All Glass and Rest of Doors = --...... - 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 =.....------- - . 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 =....v. ;......................\ ; Motor, Fan 7.5 hp X 2544 =.............................. .. - Total Sensible Space Load... Latent Load '; Infiltration 67 cfm X 4840 X 0.0071 =.......... Ventilation 1275 cfm X 4840 X 0.0071 X 0.15. People 85 X 250 =......................... Btti/Hr 72,000 . 995... 4,380 : , 265. 550 310 3,020 780 1,470 . 250 450 ,1,085 3,100 62,700 17,000 19,100 187,455 2,300 6,570 21,250 Load 30,120 : 17,600 37,230 318 CHAPTER 13 1954 Guide LETTER SYMBOLS USED IN CHAPTER 13 fraction of incident solar radiation absorbed, dimensionless; subscripts D, d, and t refer to direct, diffuse and total, respectively, solar altitude, degrees, wall solar azimuth, degrees. emissivity, dimensionless, incident angle, degrees, x amplitude decrement factor, dimensionless, T : fraction of incident solar radiation transmitted, dimensionless. . Subscripts D, d and t refer to direct, diffuse and total, respectively. ; 4> - solar azimuth, degrees. . ir = wall azimuth, degrees. A = area across which heat is being transferred, square feet. b : fraction of air .passing through coil which does not contact surfaces, coil . by-pass factor. * unit surface conductance, Btu per (hour) (square foot) (Fahrenheit degree). . Subscripts c, r, o, and i refer to convection, radiation, outdoor, and indoor, respectively. y Gs == fraction of total window area receiving direct solar radiation when shaded by y window reveal, dimensionless. _ h -- enthalpy of air per pound of dry air, Btu per pound. y.: Subscripts i, o, and 8 refer to indoor,outdoor, andsupply air, respectively. ' / = 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. 1 ,r K ~= cosine of angle of incidence for direct solar radiation striking a surface, dimenv'Jy sionless. ;; k => thermal conductivity of building material, Btu per (square foot) (hour)\p* (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. Qra - required air quantity through conditioning equipment, cubic feet per min'j?; ute. q = instantaneous rate of heat transfer, Btu per hour. j*. qt -- instantaneous latent heat load, Btu per hour. qc\ = instantaneous space latent ventilation load, Btu per hour. qa = instantaneous latent ventilation load which does not become a part of^ space load, Btuh. qm = latent heat load due to moisture transmission through materials Btu (hour)(square foot). qt = instantaneous sensible heat load, Btu per hour. q\ -- instantaneous space sensible ventilation load, Btu per hour. , qa = instantaneous sensible ventilation load which does not become a partite'? space load, Btu per hour. <?t = q* + also qti -f qax + q,,, + gex, Btu per hour. R, = low temperature radiant energy received from outdoor surroundings (do6*g. not include solar radiation), Btu per (hour) (square foot of receiving surface)|^. R = radiant energy emitted by a black body, Btu per (hour) (square foot^ Subscripts go and L refer to outdoor surfaces of glass and building, reSP!&; tively. S = rate of heat storage within a glass section, Btu per (hour) (square foot).-g^4| L sol-air temperature, Fahrenheit. Cooling Load 319 t* sol-air temperature at a time earlier than the time for which heat gain is being found by an amount that is equal to the time lag of the wall or roof, Fahrenheit. tti = temperature of indoor glass surface, Fahrenheit. tgo = temperature of outdoor glass surface, Fahrenheit. ii = indoor air temperature, Fahrenheit. , = 24-hr cyclic average sol-air temperature, Fahrenheit. * - = outdoor air temperature, Fahrenheit. t, = room supply air dry-bulb temperature, Fahrenheit. U -- overall coefficient of heat transfer of a structural section, Btu per (square foot) (hour) (Fahrenheit degree). . to -- 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 i, o, and s refer to indoor, outdoor, and supply air, respectively. REFERENCES > Application Engineering Standards for Air Conditioning for Comfort (Air Conditioning and Refrigerat ing Machinery Association, Jne., 1947, pp. 4-7). . * Minimal Replenishment Air Required for Living Spaces, by W. V. Consolario and L. J. Pecora (A.S.H.V.E. TransactionsY Vol. 53, 1947, p. 127)'. . .. * Recommended Safe Practice of the NBFXj for Hospital Operating Rooms, Pamphlet No. 56, National Board of Fire Underwriters. . , 4 Proposed Standard Solar Radiation Curves for Engineering Use, by P. Moon {Journal of the Franklin Institute, November 1940, Vol. 230, No. 5, pp. 583-617). * A.S.H.V.E. Research Report No. 1268--Summer Weather Data and Sol-Air Temperature--Study of Data for Lincoln, Nebr.,- by C. O. Mackey (A.S.H.V.E. Transactions, Vol. 51, 1945, p. 93). * Summer Weather Data and Sol-Air Temperature--Study of Data for New York City, by C. O. Mackey and E. B. Wataon (A.S.H.VJS. Transactions, Vol. 51, 1945, p. 75). 7 Summer Cooling for Comfort as Affected by Solar Radiation, by G. A. Hendrikson and J. H. Walker {Heating and Ventilating, Vol. 29, No,' 11, November 1932, pp. 14-21). Tables of Computed Altitude and Azimuth (U. S. Navy Dept. Hydrographic Office Bulletin No. 214, Vols. 1-9, Washington, D. C., 1940). The American Nautical Almanac (U. S. Naval Observatory. Washington, D. C., annual). A.S.H.V.E. Research Report No. 923--Heat Transmission as Influenced by Heat Capacity and Solar Radiation, by F. C. Houghten, J. L. Blackshaw, E. M. Pugh and Paul McDermott (A.S.H.VJE. Trans actions, Vol. 38, 1932, p. 231). Effect of Heat Storage and Variation in Outdoor Temperature and Solar Intensity on Heat Transfer Through Walla, by J. S. Alford, J. E. Ryan and F. O. Urban (A.S.H.VJS. Trans actions, Vol. 45, 1939, p. 369). Periodic Heat Flow in Building Walls Determined by Electrical An ally Method, by Victor Pa&chkia (A.S.H.V.E. Transactions, Vol. 48, 1942. p. 75).--Periodic Heat Flow-- ",^"10geneou3 Walla or Roofs, by C. O. Mackey and L. T. Wright, Jr. (A.S.H.V.B. Transactions, Vol. SO , W 293). Periodic Heat flow--Composite Walls or Roofs, by C. O. Mackey and L. T. Weight, (A.S.H.V.E. Transactions. Vol. 52, 1946, No. 1299). - Periodic Heat Transfer at the Inner Surface of a Homogeneous Wall, by H. A. Johnson (A.S.H.V.E. Transactions, Vo). 54, 1948, p. 143). " TheEffectf Solar Radiation on the Heat TransmissionThroughWalls, byF- C. Houghten, Carl Gutberlet mrn.umad,el.ph. Riao, s1e9n3b9u).rg (American Society of Testing Materials Symposium on Thermal Insulating Materials, ircwy* Spnnkled anRdeWseaaterrcChoRveerpeodrRt oNoofs., 1b1y57F--.-CSu. mHmouegr hCteono.linHg, TLo. aOdlsaosn AafnfedcCteadrlbGyuHtbeeartleGt (aAin.ST.hHr.oVu.gEh. transactions, Vol. 46, (940). pp 53) 8' by F* CR- eHsoeuagrhcthenR. eCpaorrl tGNutob.e1r0le0t2,--aCndooAlinlbgeRrteJq. uWiraehml e(An.tSs .oHf .SVi.nEg.leTrRaonosmasctinioansM, oVdoel.rn41O,1f9fi3c5e, yI*A-q3.H.V.E. T-Arcatnusaal cvtsi.oPnsre,dVicotel.d4C9,o1o9l4in3g, pL.oa28d7o).n An Air Conditioning System, by James N. Livermore n.j* ^.-S.H.V.E. Research Report No, 1195--Heat Gain Through Walls and Roofs as Affected by Solar Emission of Atmosphere and Ground, by G. V. P&TrOm`e- *le8e, 1a9n42d. pW. g. j)W. . Vnl ,by F- C. Houghten, E. C. Hach, S Aubele ii p ` oij*inai. Section, Heating, Piping dt Air Conditioning, Nov. 1951, p. 120). rologi^jlp^t^D v**! by D. Brunt (Supplement to the Quarterly Journal of the Royal Veil-fTo,?0^ Heat Gain Through Walls and R "A S R Vw' ' ` "^NSAcnoNs, Vol. 54,1948, p. 36l). bv G'v Report No. 1333--Measurements of Solar Heat Transmission Through Haf h- 165). v' parmelee. W. W. Aubele and R. G. Huebecber (A.S.H.V.E. Transactions, Vol. 54, 19^8. e^anH W W. AuWe (A.S.Harv.E^ ,1954 Guide CHAPTER 13 320 81 A-S.H.VJ2. Research Repost No. 1399-rHest Flow Through Unshaded.Glass; Design Data for Use -in Load Calculations,1 by G; V. Parmelee and W. WJAubeie (A-.SiR.VJS. Transactions'Vol. 56,1050, p. 371). II A.S.H.V.E. Reseabcb Report--Solar EnergyTransmittance of Figured RoUedGlass, by G. V. Parmelee and W. W. Aubeie (AIS.H.VJB. Journal Section, Heating, Piping and Air Conditioning, Vol. 23, No. 2, February 1951, p. 124). **A,8.H,V,E. Reseabcb Report iNo. :975-r-Studies of Solar'Radiation Through'Bare and Shaded Win- \r dows, by F. C. Houghten, Carl Gutberlet andJ. L. Blackshaw (A.S.H.V.E. Transactions, Vol. iO, 1934, ?? p. 1*0*1D).e.sign Data for Slat 'Type Sunshades for Us-e"ih:'i"Lvdad---E--s--t-imating, by G. V. Parmelee and D. J. Vild & (A.S.H.V.E. Journal Section, Heating, Piping & dir Conditioning, Sept., 1953, p. 130). The Shading of Sunlit Glass: An Experimental Study of Slat Type Sun Shades, by G.` V; Parmelee, W. W. Aubele and D. J. "$ Vild (A.S.H.V.E. Journal Section, Heating, Piping dtAir Conditioning, Jan. 1953, p. 192)..The Shading 1$ ` of Sunlit Glass: An Analysis of the Effect of Uniformly Spaced Flat Opaque SJatsMby G. V. Parmelee and ~ W. W. Aubele (A.S.H.V;E. Journal:Section', Heating,: Piping Air Conditioning, June; 1952, p. 125). ** A.S.H.V.E. Research Report. No. USO-Heat Gain-Through Western Windows With and Without ;'j 'Shading, by F. C.` Houghten and' David Shore (A.S.H.V.E. Transactions, Vol. 47,1941, p, 251). R The Mechanism of Heat Transfer, Panel Cooling and Heat Storage, Part II: Solar Radiation, by C. 8. ; Leopold (Refrigerating Engineering, June.1948,.p. 571).. , . ,= . 1 ;>* .!:<* -v a The Mechanism o! Heat Transfer, Panel Cooling, Heat Storage, by C. S. Leopold .(Refrigerating Bngi- ;% neering, July 1947, p. 33). Hydraulic Analogue for the Solution of Problems of Thermal Storage, Radiation,* Convection and Conduction,,by C. S. Leopold (A.S.iLV.E, Journal ,Section Heating, Piping cnd Av Conditioning, July 1948, p. 105), "' . . !-* ** Heat Gains Are Not Cd^ing'Loads, by C. 'O. Mackey and N. R. Gay (A.S.H.VH. Transactions, /* Vol. 65, 1949, p.413). j "Cooling Load From Sunlit Glass, by C. O. Mackey and N. R. Gay (A.S.H.VJD. Journal Section, Heating, Piping & Air Conditioning, Aug. 1952;>p. 117)'.>' M Psychrometric Factors in the Air Conditioning Estimate, by C. M. Ashley (A.S.H.V.E. Transactions, ' Vol. 55, 1949, p.9V). . 5 **See Reference Vp-3- ' ' .................... '' , 7. . . . ... t. 7 . . . ' ..--s"] **.Cooler Footcandlee for Air Conditioning, by. W. ,G. Darley (AJ3.H.VJB. Transaction, Vol. 46, 1940, p 367). Lighting and Air Conditioning Design Factors, Report of I.E.S.--A.S.H.V^E. Joint Committee on ^ Lighting and Air Conditioning (A.S.H.VJ2. Journal Section, Heating, Piping and Air , Conditioning, Sep tember 1941, p.'605). Lighting and Air Conditioning, by Howard 51. Sharp {Heating And, Ventilating, No- i . v-eVm'*bCero1m9p42ile, pd.b3y5)J. ; P. Stewart from varioui sourdee., -7 . , ,. . ." - CHAPTER 14 FUELS AND COMBUSTION Solid.Fuels: Analysis, Classification of Coals, Dustless Treatment, Classification of Cokes, Combustion of Solid Fuels, Firing Methods for Solid Fuels, Secondary Air, Draft Requirements and Regulation, Furnace Volume; Fuel Oils: Classification, Analysis, Combustion, Air Required; Fuel Gases: Classification, Heat Value, Combustion; General Combustion Principles; Air Required; Efficiency from Flue Gas Analysis; Heat Balance; Condensation and Corrosion; Soot FUELS may be classified according to their physical state as solid, liquid, or gaseous. The principal fuels used for domestic heating are coal, oil, and gas. However, coke, wood, kerosene, sawdust, briquettes, and other substances are used for heating in special applications or in localities where an adequate supply is available. Experiments are in progress in the use of a colloidal suspension of coal particles in fuel oil, but this fuel has hot attained wide-spread usage as yet. The choice of fuel is usually based on dependability, cleanliness, availability, economy, operating requirements, and control. . SOLID FUELS Analysis of Fuels Coal- has a complex composition that makes classification into clear-cut types difficult. Chemically it consists of carbon, hydrogen, oxygen, nitro gen, sulfur, and a mineral residue called ash. A chemical analysis provides some indication of the quality of a coal, but does not define its burning characteristics sufficiently. The coal user is interested principally 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. relationship between the qualities of coals and these characteristics requires considerable space; a treatment applicable to heating boilers is given in a Bureau of Mines Bulletin.1 There are two forms of coal analyses, namely, the proximate analysis and the ultimate analysis. In the proximate analysis the proportions of moisture, volatile matter, fixed carbon, sulfur, and ash are determined, analysis is more 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. saiople of coal when dried at about 220 F. To determine the volatile 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, ne sulfur content is frequently reported with the proximate analysis beause 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 are <?n' hydrogen, oxygen, nitrogen, sulfur, and ash in the coal sample determined. It is used for detailed studies of fuels, and in computing 321 *0 " i i:; 322 CHAPTER 14 1954 Guide j Fuels and Combustion a heat balance when required in testing of heating devices. Typical ulti mate analyses of the various kinds of coal are shown in Table 1.* 323 Other important qualities of coals are the screen sizes, ash fusion tem perature, friability, caking tendency, and the qualities of the volatile matter, in considering these factors the following points are of interest. The volatile products given off by coals when they are heated differ mate rially in the ratios by weight of the gases to the oils and tars. No heavy oils or tars are given off by anthracite, and very small quantities are given off by semi-anthracite. As the volatile matter in the coal increases to as much as 40 percent of ash and moisture-free coal, increasing-amounts of oils and tars are released. For coals of higher volatile content, the relative quantity of oils and tars decreases and is therefore low in the sub-bituminous Table 1. Typical Ultimate Analyses for Coals of the Wes--t. Their caking=p-ropertieLs/iuruainxugueoufrsocmoaclsoaolfsthwehiEcahsmt teoltthceompopolereterlcyo, atlos those from which the volatiles and tars are distilled without change of form, bo that they are classed as non-caking or free-burning. Most bituminous coals are strong TTaabrli ev 92. rC-.la--s---s---i-f---i-c-ation of Coals by Rank* . Legend: F.C. =* Fixed Carbon. V.W. Volatile Matter. Btu -- British thermal units. Class Gboup or| Ijmits Fixed Caubon I ^ a Btu Mineral-Matter- Requisite Physical i*BBE Basis I - Pbopebties 1. Meta-anthracite....................... . Dry F.C., 98 per cent or more (Dry V.M., 2 per 2. Anthracite.................................... DryceFn.tCo.r, le9s2s)per cent or Bru ?sa Lb C0N8TITUBNTS, Pbb Cbnt Rask Moist, MineraltnaUer- free* Moist, as Received Oxygen d.rHogyen Carbon Nitrogen Sulfur Ash Orb V Anthracite..... ........ 14,600 12,910 5.0 Semi-Anthracite...... ...... 15,200 13,770 5.0 Low-Volatile . Bituminous...________ 15,350 14,340 5.0 Medium-Volatile Bituminous................. 15,200 13,840 5.0 High-Volatile Bituminous A........ .... 14,500 13,090 9.2 High-Volatile Bituminous B_______ 13,500 12,130 13.8 High-Volatile Bituminous C_______ 12,000 10,750 21.0 Sub Bituminous A_.__ .. . ___ Sub Bituminous ...... 10,250 9,150 29.5 Sub Bituminous C......... 9,000 8,940 35.8 Lignite... .......................... 7,500 6,900 44.0 2.9 80.0 0.9 0.7 10.5 87.9 3.9 80.4 1.1 1.1 8.5 89.3 4.7 81.7 1.4 1.2 6.0 91.4. ' 5.0 79.0 1.4 1.5 8.1 89.0 - 5.3 73.2 1.5 2.0 8.8 87.7, J 5.5 68.0 1.4 2.1 9.2 87.3| 6.8 60.6 1.1 2.1 9.4 87.4, > ... ______ ........... ___ __ ___ .... __-- 6.2 52.5 1.0 1.0 9.8 6.5 46.7 0.8 0.6 9.6 6.9 40.1 0.7 1.0 7.3 91.6 ; " (Btu as received) X 100 -* (100 -- 1.1 Ash) -,f> coais and in lignite. The percentage of ash and its fusion temperature not indicate the composition or distribution of its constituents. 'f Classification of Coals HiStS A classification of coals is given in Table 2, and a brief description of tiiejg' kinds of fuel is given in the following paragraphs, but it should be recogjjnized that there are no distinct lines of demarcation between the kinds, ai^, that they graduate into each other. - . 'M Anthracite is a clean, dense, hard coal which creates little dust in handling. IfcH**-' comparatively hard to ignite, but it burns freely when well started. It is non-caking^* it burns uniformly and smokelessly with a short flame, and it requires no attention^x^ the fuel bed between firings. It is capable of giving a high efficiency in the cojnn)^ types of hand-fired furnaces. A tabulation of the quality of the various anthracite.^ sizes will be found in a Bureau of Mines Report.* Standard anthracite sizing specj|^jT| cations are shown in Table 3. Semi-anthracite has a higher volatile content than anthracite. It is not so haffe,; and ignites somewhat more easily. Otherwise their properties are similar. Semi-bituminous coal is soft and friable, and fines and dust are created by handli^te it. It ignites somewhat slowly and burns with a medium length of flame. Its properties increase as the volatile matter increases, but the coke formed is relfttivw^, weak. Having only half the volatile matter content of the bituminous coals, it be burned with less nrodurtion of smoke, and is sometimes called a smokeless coo*}. I. Anthracite. more and less than 98 ' ; per cent (Dry V.M., 8 3. Semi-anthracite......... ......... . per cent or less and more DrthyaFn.C2 .p,e8r8cepnetr) cent or Non-agglomerating 1. Low volatile bituminous coal.. more and less than 92 per cent (Dry V.M., 14 per cent or less and more than 8 per cent) Dry F.C., 78 per cent or 2. Medium coal volatile more and less than 88 per cent (Dry V.M., 22 per cent or less and more bituminous 1 than 14 per cent) Dry F.C., 69 per eent or more and less than 78 per cent (Dry V.M., 31 R Bituminous*. 3- High coal volatile A bituminous per cent or less and more than 22 per cent) Dry F.C., less than 69 per Either agglomerate mg or nonweathering/ cent (Dry V.M , more than 31 per cent); and L High coal volatile B bituminous 5. High vol atile Coal bituminoi moist* Btu, 14,000* or more Moist* Btu, 13,000 or more and less than 14,000* Moist Btu, 11,000 or more L Sub-bituminous A coal and less than 13,000* Moist Btu, 11,000 or more Sub-bitumi nous- 2. Sub-bituminous B coal. ' and less than 13,000* Moist Btu, 9300 or more and less than 11,000* Both weathering and IV. Lurniti/v ......... /1lj (/ 3. 1 2. BSLriugobwn-bnitietcu.o.m..a..il.n(...o..u...s._...._..C.._.._...c....o.v..a...l.....................................................MM-.M.roaoa,,o,niniivssMsdd*tttoBBllTBeeistsstAtuutssu.. B,tltl*eehhtss8aauss3nn,0tth09h98- 85a3ao000nn00r0*88mo3300ro00re ............................ j moist Btu less than 8300 J innogn*-agglomerat \Consolidated whtehTheoismcelawssitifhiciantiothnedloimesitnsoot ifnfcixlueddecaarfebwo"ncooarlsBwtuhicohf have unusual physical and cheUmnicoanl sporolipdeartetieds and the high-volatile bituminous and sub-bituminous AU of these coals either contain less than 48 percent dry. mineral-matter-free fixed carbon, or have mob.eteHth--aag-ng* l1wo5m,,o5e0wr0ammtinoogiiss, ttc,,lammsiisnoifeeyrraainll--mm_lo_aaw_tt-tt_eev_rrno--l.ffoaurreetaieel;euvBBugttaruuon..-u-9-p-5-o-prfe-tbr1ceen`bti`tdurm.y .inmouin?ecrlaals-sm. at.te.. . of * Moist the coal. Btu---r-e-'fers to coal containing its natural bed moisture but not including visible water on the surface # R qrccognied that there may be non-caking varieties in each group o 1 the bituminous cla^. Uoals having 69 percent or more fixed carbon on the dry, mineral-matter-free basis shall be classified "/$ to fixed carbon, regardless of Btu. . "Mi.re^seerhedafrreomthrAee.Sv.aTr.ieMti.eSstoVafnacdroiaeartld_yisn,2.,t1h9ae3g7hg, il_gSo_hmu-paevpnroalaeltaimntwigleeenaaCttn,hdbpe.irtwiu1n4meg5a;,intVhAoeaumrrsieinecrgtiocy;aaVl3ng,aSrrnooieouctnp.iye-,,tayn3gaf.ag-m-lr-o-e-Tmljyee,.srtV.aintaign.rcigMeityayteJ,,riaaagglgsg.l-o-m Ad&pted frt>m A ~ ~ IneDOn *ir'a^e nugh to permit the screened sizes being delivered free from fines J?TM! they ignite easily and burn freely; the length of flame varies with different at U,!t *s *on2- Much smoke and Boot are possible, if improperly fired, especially rates of burning. Wined ^llVn*nous coals occur in the western states; they are high in moisture when liable t.a t-enc^ break up as they dry or when exposed to the weather; they are a&d 'Snite spontaneously when piled or stored. They ignite easily and quickly, t0breaLe-a wedium length flame; are non-caking and free-burning; the lumps tend * into small pieces if poked; very little smoke and soot are formed. !P>tl is 0f woody structure, very high in moisture as mined, and of low heating 1954 Guide CHAPTER 14 3Z24 valuej 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 spontaneous 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 ^ tbg ashpit codiinue to burn. Very littJe smoke or soot- is formed. ,v. Dustless Treatment a In order to allay the dust, the more friable coals are sometimes sprayed .' with various petroleum products, a solution of calcium chloride, or a mix- J ture of calcium and magnesium chlorides. . .; The coal is usually treated at the mine, but sometimes by the local dis- ; tributor just before delivery. The salt solutions are sprayed under high w Table 3. Standard Anthracite Specifications" '* Test Mesh Round T Oversize 1Oveb In. Max. % Broken Egg.. Siove Nut. Pea............. Buckwheat Rice........... Barley....... NNoo..*45Ap.p....r...o.....v....e.....d.......a...n.(id aHd7--o*pted, e,jffec,.t..i.v..e...J..ulyj 28,3(11947, bj y the Anth_r_a_cite Cojmmittee (Manual of Statistical Information, Anthracite Institute). '$$ k When elate content in the sizea from Broken to Nu t inclusive is less than above standards, bone confcectvv may be increased by one and one-half times the decrease in the slate content under the allowable limits, but-V .slatAe ctoonletreanntcsepoefci1fiepderacebnotviessahllaowll nedotobnethexecemeadxediminumanpyerecveenntatg. e of undersize and the maximum percentage^' of asAhschondteetnetr.miTnhaetiomnsaxaimreuomn apedrcryenbtaagseis-of unxdersize is applicable only to anthracite as it is produced sM'y Slate is defined as any material which has less than 40 percent of fixed carbon. ' theBporneepaisradteiofninepdlaanst,any materia) which ba3 40 percent or more, but less than 75 percent of fixed carbon. pressure, using from 2 to 4 gal or from 5 to 10 lb of the salt per ton of/;, coal, depending on its friability and size. Oil for the dustless treatment^- of coal is also applied under high pressure, in concentrations of 1 to 8 per ton of coal, depending upon the characteristics of the coal and oil. Dustless treatments, which are of such a corrosive nature that they may _ damage coal handling or burning equipment, should not be used. Classification of Cokes <si' C ^.4 "O. Coke is produced by the distillation of the volatile matter from coal. The typeiofij coke depends on the coal or mixture of coals used, the temperatures and time of distil lation and, to some extent, on the type of retort or oven. Coke is also produced as * A residue from the destructive distillation of oil. (,>'7 High-temperature cokes. Coke, as usually available, is of the higb-temperstuW>d type, and contains between 1 and 2 percent volatile matter. High-temperature co&4r| are subdivided into beehive coke of which comparatively little is now sold for dome'spt.. use, by product coke, which covers the greater part of the coke sold, and gas-house;cofe | The differences among these three cokes are relatively small; their densenessi*'!? r hardness decrease and friability increases in the order named. In general, the lilp^rj and more friable cokes ignite and burn more readily. , .' ,1..> l/ow-iemperature cokes are produced at low coking temperatures, and only a portifl?,*| of the volatile matter is distilled off. Cokes, as made by various processes underjySg velopment, have contained from 10 to 15 percent volatile matter. In general, cokes ignite and burn moTe readily than high-temperature cokes. The properties,?^; various low-temperature cokes may differ more than those of the various high;teiBgr- Fuels and Combustion 325 perature cokes because of the differences in the quantities of volatile matter, and because some may be light and others briquetted. . Petroleum cokes, which are obtained by coking the residue left from the distillation of petroleum, vary in the amount of volatile matter they contain, but all have .the common property of a very low ash content, which necessitates the use of refractory pieces to protect the grates from being burned. ' 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 bums 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 regu lating solely by means of the cold air check and the air inlet damper. Buckwheat size coal, for best results, requires more attention than pea size coal, and in addition the smaller size of the fuel makes it more difficult . to burn on ordinary grates. Greater care must be taken in shaking the grates than with the pea coal on account of the danger of having fuel fall 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 exercised in manipulation of the gTates, 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 buckwheat coal to maintain a uniform heat output and, consequently, 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 warming up. A uni- ,rm 'ow fire will minimize the clinker formation and keep any clinker ormed in an easily broken up condition so that it readily can be shaken though 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 principally in stokers 326 CHAPTER 14 1954 Guide ' . of the domestic, commercial and industrial type. No. 3 buckwheat anthra cite, or barley, has no application in domestic heating. -!t. ` 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 coals. 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 s*hou'ld' never 1be fciredJ o--v--e-r41t--he entire ffiunaell VbioeHd qa+t. nonnfet time. A portion of the glowing fuel should always be left exposed to i. ignite the gases leaving the fresh charge. \ ; The importance of firing bituminous coal in small quantities at short j- intervals is discussed in a U. S. Bureau of Mines technical paper.1 Better s. combustion is obtained by this method in that the fuel supply is main- v tained more nearly proportional to the air supply. :f If the coal is of the raking kind, the fresh charge will fuse into one solid -'!< mass which can be broken up with the stoking bar and leveled from 20 y min to one hr. after firing..depending on the temperature of the firebox.^t Care should 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 high temperature,Sp zone at the top of the fire, where it will melt and form clinker. The*} stoking bar should be kept as near the grate as possible, and should be X raised only enough to break up the fuel. With fuels requiring stoking it,5;. may not be necessary to shake the grates, as the ash is usually dislodged;/; during stoking. % It is acknowledged- th at it may be difficult to --app1-ly *tvh.e,, outlined^ methods to domestic heating boilers of small size, especially when frequent]} attendance is impracticable. The adherence to these methods insofar as|?j practicable, however, will result in better combustion. The output obtained from any heater with bituminous coal will usuallycs, exceed that obtained with anthracite, since bituminous coal bums moigg rapidly than anthracite, and with less draft. Bituminous coal, howeverg will usually require frequent attention to the fuel bed. Preventing Smoke ' ' ISr:-. V|y In general, time, temperature and turbulence are the essential requitf^ ments 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. ``It; Checker or alternate firing, in which the fuel is fired alternately !,eD}5 separate parts of the grate, maintains a higher furnace temperature and]; thereby decreases the amount of smoke. Coking and firing, in which the fuel is first fired close to the firing dqo|| and the coke pushed back into the furnace just before firing again, pi|? duces the same effect. The volatiles as they are distilled thus have "g;: pass over the hot fuel bed where they will be burned if they are mixed wiK| sufficient air, and are not cooled too quickly by the heat-absorbing surfaccgj| of the boiler. Steam or compressed air jets, admitted over the fire, create turbuleaS|| in the furnace and bring the volatiles of the fuel more quickly into contact}! . Fuels and Combustion 327 with the air required for combustion. These jets are especially helpful for the first few minutes after each firing. Frequent firings of small charges shorten the smoking period, and reduce the density. Thinner fuel beds on the grate increase the effective combustion space in the fur nace, supply more air for combustion, and are sometimes effective in reduc ing the smoke emitted, but care should be taken that holes are not formed in the fire. A lower volatile coal or a higher A.P.I. gravity oil always produces less, smoke than a high volatile coal or low A.P.I. gravity oil used in the same furnace and fired in the same manner. The installation of more modern or better designed fuel-burning equip ment, or a change in the construction of the furnace, will often reduce smoke. The installation of a Dutch oven, which will increase the furnace volume and raise the furnace temperature, often produces satisfactory results. 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 a considerable ' investment in special apparatus is often necessary. 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 designs 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 pol lution of the atmosphere is to be prevented, some type of dust and cinder catcher must be installed. Firing Methods for Semi-Bituminous Coal The Pocahontas Operators' Association recommends the central cone method of firing, in which the coal is heaped on to the center of the bed forming 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 sides, and the fines h> remain in the center and be 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 firing door be kept closed, as the thinner fuel bed around the sides admits the required air. Firing Methods for Coke Coke ignites less readily than bituminous coal and more readily than anthracite, and burns rapidly with little draft. In order to control the air Admitted to the fuel it is very important that all openings or leaks into je ashpit be closed tightly. A coke fire responds rapidly to the opening ! tlle dampers. This is an advantage in warming up the system, but it so makes it necessary to watch the dampers more closely in order to prevent the fire from burning too rapidly. In order to obtain the same terval of attention as with other fuels, a deep fuel bed always should be attained when burning coke. The grates should be shaken only 328 CHAPTER 14 -1954 Guide '' /slightly in. mild weather, and should be shaken only until the first red 3;. /particles drop from the grates in cold weather. , The best ,size of coke for i general use, for small fire-pots where the fuel depth is not over 20 in., ,is that which passes over a 1 in. screen and through a lj in. screen. For' large firerpots 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 used, but-a coke of uniform size is always more satisfactory. Large sizes of coke should either be mixed with fine sizes or broken up before using. : SECONDARY AIR " ! When bituminous coal is hand-fired in a furnace, the volatile matter in the fuel distills off 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. ' Fig. 1. Combustion op Fuel in a Hand-Fibbd Furnace ,/ 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. I.4 The free oxygen of the air passes through the grate and the ash 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 0t- 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 admitted through the firing door, in an attempt to burn carbon monoxide, as well as the volatile combustible distilled from the freshly fired fuel. " The division of the total into primary and secondary air necessary produce the same rate of burning and the same excess air, depends on!8' number of factors which include size and type of fuel, depth of fuel bed, and size of fire-pot. '/ Size of the fuel is a very important factor in fixing the quantity of second-. ary air required for non-caking coals. With caking coals it is not-?0; important, because small pieces fuse together and- form large lump|T Fortunately, a smaller size fuel gives more resistance to air flow througj??. Fuels and Combustion 329: the fuel-bed, and thus: automatically causes a larger draft above the fuel bed. More secondary air / is drawn through the same slot openings, but, nevertheless, the smallest'size of fuel will require the largest seconds ary 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 secondary air-is admitted through the- slots of the fire door. However, unless the slots are closed when secondary, air is no longer beneficial, the decrease in efficiency during.the remainder- of the firing cycle, because of excess air, may more, than offset the gain, resulting from the secondary air at the beginning of the firing period. Unless the secondary air can be readjusted between firings,.it 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 slots of domestic furnaces and boilers. When attention : is given between firings, the efficiency of combustion can be raised, appreciably by admitting secondary air over a bituminous coal fire, to bum the gases and reduce the smoke. The smoke produced is a good indicator, and that opening is best which reduces the smoke to a minimum. Too much secondary air will cool the gases below the ignition point, and prove harmful instead of beneficial. Secondary air that enters the combustion chamber too far removed from the zone of combustion, will also be harmful, because the oxygen in the secondary air will not react with any unburned gases, unless the mixture is subjected to high temperatures. , Draft Requirements for Coal and Coke Firing . , The draft required to effect a given rate of burning the fuel is dependent on the following factors: (1) kind and size of fuel; (2) grate area;,.(3) thick ness 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 *1 > and more frequent cleanings to keep its resistance down.' Insufficient oraft also restricts the control that can be accomplished by adjustment t the dampers. For draft requirements see Chapter 17. . The quantity of excess air present has a marked effect on the draft quired to produce a given rate of burning. If the excess is caused by Drnfi 10 *he/uel bhd, or. an extremely thin fuel bed, it is often possible to Th tv higher rate of burning by increasing the thickness of the bed. ,6 thickness of the fuel bed should not, however, be increased too much, <n,J^se bhe increased draft resistance will reduce the rate of primary air ^PPly and the rate of burning, . rft Regulation for Coal-and Coke Firing the varying heating load demands present in most instalof ^ s' **18 necessary to Vary the rate of fuel burning. The maintenance by re<n *?roPer a'r supply for the various rates of burning is accomplished are jPnst/on of the drafts. Methods of draft regulation used for solid fuel . wn m Fig. 2. The air enters through the ashpit draft door, firing CHAPTER 14 1954 Guide: 330 door, and by leaks in the setting, whereas the gases leave only through theh outlet. By throttling the gases with the damper in the outlet all the air' entering by each of the three intakes is reduced in the same proportion," thus maintaining about the same percent of excess air. If inlet air is con-, trolled by the ashpit draft door, the air admitted through the ashpit.is reduced, while it is increased through the other two intake openings;! resulting in an increase of excess air. A considerable increase in the efficiency of hand-fired ftfrnaces and boilers can be realized -by regulating' the air supply by means of the damper in the outlet instead of the ashpit: damper, lise, 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 closing of the> Fuels and Combustion 33-1 of crude oil could be varied considerably to suit seasonal changes in demand or gradual trends from year to year. At present gasoline represents about 43 percent and fuel oil (including kerosene) about 22 percent of the yield from crude oil. Crude oil is distilled in towers at atmospheric pressure to produce gaso line, naphtha, kerosene distillates, and colored distillates, and leave straightrun residues. The colored distillates are distilled further to produce light distillate fuel oils, some lubricating oil, wax, etc., whereas the straight-run residues are distilled under vacuum to produce heavier distillates- The residual fuels remaining can then be passed through cracking plants to produce more gasoline, cracked kerosene, cracked distillates, and cracked residual fuel oils. The exact processes used depend on the proportions of the various end products desired, and to some extent upon the composi tion and characteristics of the crude oil. Fuel oils may be described as straight-run fuels, thermally-cracked fuels, catalytically-cracked fuels, or blended fuels depending on the refining proc ess used to produce them. Straight-run fuels are those produced by distil lation under atmospheric pressure or a vacuum without decomposition of the hydrocarbons by cracking. Thermally-cracked fuels are those produced by a cracking process involving elevated temperatures (850-1100 F) to decompose some of the heavier hydrocarbons. Catalytically-cracked fuels are those produced with the aid of an alumina-silica catalyst in the crack ing process at lower temperatures than those used for thermal cracking. Blended fuel oils are mixtures of any of the above three types. Over 90 percent of all No. 5 fuel oils are blended. There is no particular problem involved with the burning of a blended oil providing it is blended from two oils which come from the same source. If the oils are not properly blended under heat or pressure, they will ex hibit a degree of instability in storage, resulting in sludge formation and a tendency to plug filters and atomizing nozzles in high pressure burners. This is especially true when the oil burning rate is 1 gpm or less. There is some evidence that the viscosity of blended oils is generally higher than for straight run fuels of the same grade. The viscosity of the >f can change the spray pattern such that smoking and pulsation may result. The adverse effects of high viscosity can be alleviated to a con siderable degree in high pressure burners by the use of higher atomizing pressures. In all cases the pressure should be 100 psig or higher and in some cases pressures up to 150 psig have been used to correct difficulties attributed to high viscosity oil. Analysis of Fuel Offs Crude oil in its natural state contains primarily paraffin hydrocarbons wJiemical formula C0f/2n+2, naphthene hydrocarbons (formula C,,H2n), and ^ hydrocarbons (formula CnHin-t) where n is a whole number, cont ' broc*.ucecI by pure distillation, that is the straight-run fuel oils ine am essentia% these same hydrocarbons. Those produced by erack- Presses may contain generally all the hydrocarbon series from ofy-to C,,//2,,_u, and especially do they contain appreciable percentages ,,a , ? 0lefin hydrocarbons which are relatively less stable than the paraffin, hydr ene' an^ aromatic hydrocarbons. The paraffin hydrocarbons are hydro8e,i~Saturated' are amonS the most stable, and have the highest fuel nen~carbn ratio of any of the hydrocarbon series. The straight-run ratio Is , ve the highest paraffin content, the highest hydrogen-carbon Dd are the most stable of the fuel oils. The thermally-cracked fuel Fuels and Combustion 333. oils have the lowest paraffin content while the catalytically-cracked fuel oils are intermediate in paraffin content aiid stability. The hydrogen- carbon ratio of straight-run fuel oils ranges from 0.155 to 0.170, and- in catalytically-cracked fuel oils ranges from 0.133 to'0:156-, -while it is sombj what lower for 'thermally-cracked fuels; The blending of straight-run oils with cracked oils is common practice to improve the paraffin content, stability, and ignition characteristics of fuel oils. -' A high paraffin content and a high hydrogen-carbon ratio are generally desirable characteristics for domestic fuel oils and consequently, the straight-run distillates are better suited to this vise than the fuel' oils produced by the various cracking processes. On the other hand, thermally-cracked fuel: oils often have a. lower pour point and a lower viscosity: than comparable straight-run fuel oils. The color and stability of cracked fuel oils can be much improved by treatment with sulfuric aicd, by neutralization;, and by redistillation. Grade Classification of Fuel Oils ^ Fuel oils are most commonly classified by dividing them into grades in accordance with the Commercial Standard (CS12-48) entitled Fuel Oil published by the U. S. Department of Commerce. These specifications, given in Table 4, conform-to ASTM Materials Tentative Specifications for Fuel Oils D 396 - 48 T. Oils may be classified roughly by specific gravity but it is not an adequate index of the suitability of an oil for a given purpose. 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, sulfur content, distillation characteristics, and vis cosity. " The flash point of an oil is important with regard to safety in storage and ease of ignition in systems employing 'automatic ignition.'' The distil lation characteristics determine whether or not the oil can be completely 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 desirable for outdoor storage-in cold climates. Sediment, carbon residue, and ash should be low to prevent clogging of strainers and the accumulation of unburned material in the burner. A low viscosity allows the fuel oil to flow through supply lines readily and to be broken up into,small droplets ln atomizing type burners. The sulfur content is of importance-because sulfur compounds corrode the burner and heating system or because un desirable compounds of sulfur may be formed in certain industrial processes, home of these characteristics of a fuel oil are required to lie within certain ''fs for each of the grades of fuel oil listed in Commercial, Standard GS12-48. Some fuel oils do not fali into any ..of the. grade classifications * the Commercial Standard because failure to. comply with all of the re- fiuirements of one grade does not automatically place the- fuel oil in the ext lower grade, unless it meets all of the requirements of the lower grade. By ultimate analysis-the No. 1 and No. 2 fuel oils contain 84 to 86 per- ent carbon, 12,0 to 13.5 percent hydrogen, one to three percent oxygen dj ^ltrgen, and 0.5 percent or less of sulfur. The heavier grades of fuel lj' os- 4, 5 and 6, may contain as much as 88 percent carbon, as low as WdqCent .kydr0Sen> and considerably more sulfur than is permissible in variation in the constituents of different fuel oils and the differ(liff refiuing methods used, the API gravities and calorific values of the erent grades of fuel oil cover a range in each grade with some overlapping 3O3U41 . CHAPTER 14 1954 Guide between domestic grades and between commercial and industrial grades. ` The relation between the API gravity of fuel oils and their palorific value is shown in Table 5. Grades No. 1 and No. 2 are used predominantly in domestic heating equipment whereas grades 5 and 6 are used in commercial and industrial burners. Grade 6 usually requires preheating to increase its fluidity and to permit atomization, whereas grade 5 is used in some burners without preheating. Grade 4 fuel oil does not require preheating and can be burned satisfactorily in a limited number of domestic burners. COMBUSTION OF FUEL OILS Many theories have been advanced during the past century to explain the mechanism of combustion of hydrocarbons in oil burners and other devices used for producing heat or light. These theories have been modi fied from time to time to agree with hew experimental evidence. Much Table 5. Approximate Gravity and Calorific Value of Standard Grades of Fuel Oil N .Commercial Standard o BApproximate Gravity Range Calorific Value tu Per Gallon 138,800-132,900 1 2 .4 5 6 35-45 26-40 12-25 10-23 8-17.5 144,300-135,800 153.000- 145,000 154,600-146,200 156.000- 149,700 still remains unknown about the process of decomposition and combustion! of hydrocarbons. >> Only three theories will be discussed here: (1) the carbonic combustion theory, (2) the aldehydeous combustion theory, and (3) the chain reaction theTohrye. carbonic combustion theory postulates that thermal destruction! of hydrocarbon molecules is likely to occur if (1) the oil is suddenly exposed' to intense heat without allowing time for previous evaporation, (2) the' oil and air are inadequately mixed, and (3) there is no preheating of the' air or mixture. According to this theory the hydrocarbons would ti' thermally decomposed into hydrocarbons of lower molecular weight along, with some free carbon atoms released under the conditions just describMj The free carbon atoms may produce smoky combustion while those carbon atoms that are oxidized to carbon dioxide will produce a yellow luminous flamThee. aldehydeous combustion theory is based on the evidence that al4< hydes, alcohols, and possibly peroxides are formed as intermediate product; when hydrocarbons are decomposed and oxidized to the final products: combustion. The formation of formaldehyde is certain since it can'', identified in the flue gases from blue flame oil burners when insuffici!; combustion air is provided. Alcohols have been identified by certain'^1! vestigators during the oxidation of methane and ethane. Aldehyde1 combustion is illustrated by the blue flame oil burner and the condition, conducive to this type of hydrocarbon decomposition consist of (1) allow# the oil time and opportunity to evaporate completely prior to combustiojV (2) mixing the air and oil vapor thoroughly before combustion, and (3)Pf|' heBatliunegatnhde yaeirlloowr tfhlaemmeicxotumreb.ustion can be demonstrated by the apparj'|| Fuels and Combustion 335 illustrated in Fig. 3. If methane is burned in an atmosphere of air, as in burner A, a yellow flame will result, whereas the introduction of the air for combustion in the center of a stream of methane, as in burner B, will result in blue flame combustion. . As the center of the flame in burner A is exposed to intense radiation the methane is thermally decomposed and liberates carbon particles which emit a yellow luminous flame during oxida tion. In burner B the center of the'flame cone is filled with air which can not decompose under heat, the methane gas at the zone of contact with the air is only moderately heated because of outward radiation, and the air is preheated in the center as it approaches the flame; each of these conditions tend to produce aldehydeous combustion. It is probable that the chain reaction theory is an extension of the alde hydeous combustion theory since most investigators who have studied the former have observed that the formation of aldehydes is one of the steps n the combustion process. It has been well established that fuel oils Fig. 3. Illustration of Blue and Yellow Flame Combustion must be gasified before combustion can occur, and that molecules of a hydrocarbon and oxygen do not combine directly with each other to form carbon dioxide and water vapor, but pass through intermediate reactions in the process. Lewis and von Elbe,5 Pease, and others6 have advanced the theory that the reactions between hydrocarbons and oxygen are probably chain reac tions. This theory postulates that a great many different reactions take place simultaneously or progressively between molecules, atoms, and radi cals in a mixture of hydrocarbons and oxygen. Some of these reactions produce particles or substances that tend to accelerate the reactions while others tend to slow down the process. Also, temperature, pressure, light and certain catalytic agents all may affect the speed and nature of these processes. The kind of intermediate products formed before combustion ls cmplete depends on the physical conditions mentioned, as well as the molecular structure of the particular hydrocarbon participating in the re action. Aldehydes, methyl and ethyl alcohols, formic acid, and other Vostances, have all been identified as intermediate products in certain orwk nS' ^le chain reaction theory, in reality embraces and elaborates the aldehydeous combustion theory. 0*1 Burning Indexes (jl^,m*ml>er of indexes have been used, or proposed, as an indication of Qj j rning qualities of fuel oils based on one or more physical measure ' ts made on the oil. These may be summarized as follows: 336 CCHHAAPPTTEERR 1144 . ,1954 Guide F4 .. A. Indexes based.on. a single physical test:.fl) API gravity7, (2) Aniline point, It (3) Institute of Petroleum smoke test, (4) Carbon-Hydrogen ratio based on flue gasi-V .analysis or ultimate analysis, and (5) Percent aromatics determined'by sulfuric acid (absorption tests. ' ' "" 1 --i ... , Bi,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-characters -zatiori factor11 basedoh specific gravity and average boiling point, (4) Burning index17 .based on API gravity and 50 percent distillation point, and (5) Estimated.)Carbon- Hydrogen ratio1 based on API gravity aniline point, and boilihg point. ' 5 Various investigators have shown correlation between one or-'more of these indexes and the performance of fuel oils in oil burners. Experiments' Fuels and Combustion 337: fuel oil indexes for particular applications, even though correlations be tween them and burning qualities have been observed: In other words, none of the above mentioned indexes has yet gained sufficiently wide usage to replace the grading of oils by Commercial Standard CS12-48. Experiments have shown that thermal decomposition or cracking of hydrocarbons begins at a temperature of approximately 680 F at atmos pheric pressure, although the temperature of cracking varies somewhat above and below this value. Thus pure distillate fuel oils, whose end point does not exceed this temperature, can usually be completely evaporated in vaporizing-type oil burners at atmospheric pressure without leaving a residue or without cracking of the hydrocarbons. Fuel oils that cannot be completely evaporated below 680 F are likely to undergo cracking in vaporizing type burners, with the resulting possibilities of smoky combus tion and residues in the oil burner. A complete distillation curve cannot usually be determined for fuel oils containing fractions that evaporate above 680 F. Since No. 1 grade fuel oil in Commercial Skmdard CS12-48 has a maxi mum end point of 625 F, it can in most cases be completely evaporated in atmospheric vaporizing burners without cracking, 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 percent point, would frequently be cracked in a vaporizing burner: How ever some No. 2 fuel oils do not crack before complete evaporation takes place. Vaporizing-type burners can generally 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, preheating of the combustion air and fuel, com plete evaporation of fuel before it is exposed to intense heat, and thorough mixing of the air and gasified fuel promote complete combustion without smoke and with a minimum of excess air. In pressure-type burners pre heating of the combustion air, a maximum of air turbulence, good atomiza- bon of the fuel, and high combustion chamber temperatures (preferably red hot) promote smokeless combustion with a minimum of excess air. , Natura_l dr_a__ft_Kbuwuuir-mrnvueovurcss. xd-i*o-en-p-e-w-n-id1th-oan m1t1hineimmuomtivoaftienxgcefsosrcaeir.of a chimney to induce enough air into the burner for complete combustion. Forced draft Burners are supplied with combustion air by means of a blower or fan; the chimney merely conducts the flue gases outdoors and prevents leakage of flue gases inside the building. More details on the operation of the different kinds of oil burners and on chimneys and draft will be found in Chapters 15 and-17 respectively. FUEL GASES iL "el gases employed for various heating and air conditioning processes fi)al f ut` United States fall into three broad classifications: natural, comh tUred' and hquefied petroleum. Natural gas is a mixture of several t_. fustible gases and, usually, a small percentage of inert gases obtained geologic formations. Natural gas is produced in significant amounts ,, , states. TTepxyaass iisf by ffa--r the 1largest prod'ucer, f*ol~l~owed-b-y-L-o-ui-siana, raacjg ?tna' California, Kansas, and West Virginia. Manufactured gas is by the distillation or cracking of oil or coal, by the steam carbon Fuels and Combustion 339 reaction, or by combinations of these processes. Liquefied petroleum gases (propane and butane) are higher hydrocarbon gases normally obtained as a by-product of oil refineries or by stripping natural gas. These two com pounds are generally gaseous under usual atmospheric conditions although they can be liquefied by the application of moderate pressures at normal temperatures. The demand for gaseous fuels has increased so tremendously during the past 25 years that few cities now can be said to depend solely on one source of supply. During peak load periods, heating demands on natural gas distribution systems may necessitate augmenting the base supply with supplemental fuels such as high Btu oil gas or liquefied petroleum gasair mixtures. The supply of manufactured gases may be similarly increased by adding natural gas, reformed refinery gases, or relatively low heating value mixtures of liquefied petroleum gas and air. In American gas practice the heating value of a gas and appliance effi ciencies are based on the gross heating 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 employed for do mestic heating processes are shown in Table 6.15-16,11 v18 . Natural gas contains from 55 to 98 percent methane with various per centages of higher hydrocarbons, chiefly ethane. In addition to these components, small quantities of non-combustible gases such as carbon dioxide, nitrogen, and helium are sometimes present. Percentages of the different components vary with the area from which natural gas is with drawn. They may even vary slightly from any given well 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 manu factured 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 content of manu factured gases, thus making it possible to serve more customers through the existing distribution system. Mixed gases are a result of increased distribution of natural gas, through ranscontinental transmission lines, into areas having existing manufac,uTMrgas facilities. In such instances some gas companies supply a 600 p>0 Btu mixture (See Table 6). In some territories these mixtures are stributed as an intermediate step in changing over from manufactured Sas to natural gas. Although the burden of adjusting installed heating na air conditioning equipment and supplying new orifices and burner equipment is generally assumed by the gas companies when the gas is a!'8ed, it is advisable to consult the local gas company to insure that Tupment is provided with proper orifices and burners when installed. Most states enforce legislation through their public service commissions 340 CHAPTER 14 1954 Guide 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 constituents of city gases are not necessarily the same in different districts nor even at succes sive stations in the same district. In every community, however, the objective is to maintain variations in composition and gas pressure within limits which 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 liquids 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 substantially 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 gases, mixed with air, or in undiluted form, are also extensively employed by gas companies to aug ment their base load supplies during peak load periods. In some smaller communities, where gas manufacturing 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 same manner, as manufactured or natural gas. COMBUSTION OF GASEOUS FUELS :; Gas burners employed in domestic heating appliances are generally of. the non-luminous flame or Bunsen type. Part of the air required for com bustion is inspirated as primary air into the burner mixing tube where,.irt mixes with gas, and then takes part in combustion at the burner ports. As the amount of primary air is seldom sufficient to support complete com bustion, additional air is supplied to the burner flames around the'periphery of its ports.; This 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 adjusted, its flames w generally have a clear, blue appearance. Yellow flames are indicative of insufficient primary , air supply, and possibly of incomplete combustion; An appreciable updraft is seldom, if ever, present even in flue-connected gas heating appliances, because most appliances of. this kind are equipped with a draft hood which reduces the chimney draft at the appliance,, is important to note that gas furnaces and boilers, as well as most classes of Seating equipment, are designed to create their own draft.'j',,;' The air-to-gas ratio ip a Bunsen burner head has a decided effect ontb rate of flame propagation. The gas-air mixture must flow from the burng ports faster than the flame burns, otherwise flashback will occur. AjS flashback condition normally results either from an excess amount,; primary air or insufficient gas or both. Conversely, the velocity of issuing mixture must not be so high that the flame will be blown from. ports, a condition known as lifting. Fortunately, contemporary typefM such burners have a rather wide range of flexibility in capacity and Fuels and Combustion . 341. ment. In addition to this characteristic, gas supply is normally so uni-' form that if a gas heating appliance is properly adjusted when it is installed, its burners, with occasional 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. ;It should be recognized that a ehangein fuel gas will change the operating C02 value. For example, an appliance operating on car- buretted water gas at 20 .{jercent 'excess air will'have 14.2 percent CO*;in the flue gases. If a change is made to coke oven gas at the same gas in put rate, with the excess air maintained at 20 percent, the operating CO* would drop to 9.2 percent. : / Luminous flame burners are occasionally used in central heating gas ap pliances. With these devices all air required for complete combustion is supplied to the flames as secondary 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 flame 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 com bustion 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 American Gas Asso ciation 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 which do not exceed the name plate input rating. These appliances normally draw in from 20 to 50 percent excess air, depending on the type and general design. As has been indicated, some excess air is necessary to insure complete combustion at all times and also to provide a reasonable degree of flexibility in performance. Various types of appliances used for gas space heating purposes are described in Chapter 15. ' Care must be exercised to insure adequate air supply for combustion equipment installed in buildings or other structures. Where the equip ment ig closely confined, as in closets or small furnace or boiler rooms, the an supply must also provide for ventilation. Current recommended prac tices are: 1 b Where the equipment is not closely confined (typical cellar installation or equivaient) provide not less than 1 sq in. of free access to outside air for each 1000 Btu Pr hr heat release of fuel consumed. Infiltration into conventional frame or brick 3Jktrurtion, unless unusually tight with storm windows and tight doors, provides 2. Where the equipment is closely confined, provide two openings to outside air or spaces freely communicating to the outside. One opening should be near the P of the equipment enclosure and the other near the bottom. Each opening should bur6 n\0t *ess fban S sq in. of free area for each 1000 Btu per hr heat.release of fuel the'iand should communicate to air source or outside by suitable ducts. Where So enclosure is in a building of otherwise conventional construction, and the air thanC<i W'^ he the normal infiltration into building, each opening shall have not less n 1 sq in. of free area for each 1000 Btu per hr.heat release. |0 j Clearances from equipment to closely confining enclosures should conform to mat es to standards listed by recognized agencies such as A GA Testing Labne*'? and Underwriters' Laboralories.K See Fig. 5 for details concerning installs- 342 CHAPTER 14 1954 Guide tion of gas burning equipment.15 For installation of equipment burning other types of fuel, refer to the National Building Code of the N .B.F.U. 4. Certain additional precautions may be required for certain fuels (such as un diluted liquefied petroleum gas) and consequently provisions of local codes and other authoritative agencies should be followed. 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 com monly called ash. Moreover, unless sufficiently high temperatures are employed and an ample supply of oxygen properly distributed is present, Fuels and Combustion 343 Fig. 5. Illustration Showing Aik Openings Necessary to Supply Air for Combustion When Appliance is Installed in Confined Space A. Ventilating air outlet register for furnace room, 1 sq in. free area for each 1000 Btu per hr furnace inputfv located above relief opening of draft hood. Register must not be blocked by drapes or other furnishings.,^B. Both registers must either face same large ventilated interior space or extend to 6uch space by meansflf? of ducts. Vertical distance C/L to C/L of registers should be not less than.3^4 ft. . '.k'?: C. Suggest room access door be not less than 6 ft high by a width sufficient to provide for installation.-^ ' or removal of furnace. At least 2 ft horizontal clearance should be provided in front of furnace when closet^ door is open, or 18 in. when door is closed. . ,tV. D. Combustion and ventilation air inlet register for furnace room, 1 sq in. free area for each 1000 Btovt; per hr furnace input, located at or below combustion air inlet to furnace. Register must not be blocked.byjp* drapes or other furnishings. jr-V E. Air circulated by furnace must be handled by ducts which are sealed to furnace casing and are entirely*./ separate from means provided for supplying combustion and ventilation air. F. Spacing between draft hood and wall at least 6 in. (unless approved for closer spacing). If flue produeiffc*' may be directed toward wall, 12 in. spacing recommended. aB' G. No part of furnace casing closer than 6 in. to wall (unless approved for closer spacing). H. Flue should terminate above peak of roof and above nearby walls to assure satisfactory flue perforc^; anoe. In installations where the flue terminal is below nearby walls or roof peaks, an effective vent <*>*?, should be used. '` the combustible constituents of solid, liquid, and even gaseous fuels can?g not be completely burned. Incomplete or partial combustion of all fuelsg produces toxic gases, such as carbon monoxide, with smaller quantiti. of aldehydes, ketones, and other hydroxylated hydrocarbon compoundsj| This fact indicates that, while combustion processes involving cowmoOM types of fuel may be regulated by experienced operators to produce t^, most efficient results, normal combustion processes can be So unbalanced ask to create hazards unless, both design and operation are planned with a knowH. edge of the fundamental principles of combustion. Combustion may be defined as the chemical combination of a substari^J; with oxygen resulting in the evolution of heat, and usually some light. Tb|g rate of combustion depends upon the rate of reaction of the substance oxygen, upon the rate at which oxygen is supplied, and upon the temper*-;. Lignite Fuel Oil - Fl*e Gas Tig. 6. Flue Gas temperature Shown. Losses with Various Fuels5 Loss is Based on 65 F Room Temperature. 344 CHAPTER 14 1954 Guide ture obtained due to surrounding conditions. This is combustion 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 jthe combustion process. For a continuous reaction, as in heating processes, jit is necessary to establish an effective balance between rates of removing iheat and of supplying fuel and air or oxygen to keep the reaction going. |In establishing such a balance, consideration must be given to the removal ior venting of products of combustion, so that the entire process is one of `flow wherein draft conditions in the combustion space are important. i Complete combustion is obtained when all combustible elements in a fuel are oxidized by all of the oxygen with which they will combine. All ioxygen or air supplied is generally not utilized, and this excess portion is commonly referred to as excess oxygen or excess air. Excess air is usually expressed as a percentage of the of air required for perfect combustion. ! Perfect combustion results when the exact amount of oxygen required jfor complete combustion of all elements of a fuel is supplied and utilized.. jThe percentage of carbon dioxide contained in the products of combustion ': from such a reaction is obviously the maximum attainable and.is referred To as the ultimate CO2 or maximum theoretical percentage of carbon dioxide:; 'This condition of perfect combustion, without having excess air or oxygen left from the reaction, is seldom, if ever, realized in practice. Most types!; of heating equipment must be sufficiently flexible in performance to pro-2 vide complete combustion with not only variations in the quality of a fuel:" but also changes in the rate at which it is supplied. This situation makes,f- it advisable, from a practical standpoint, to insure complete combustion but not perfect combustion in the sense expressed above, To attempt to dot. so would undoubtedly result eventually in unsatisfactory performance^ especially from a safety standpoint! Consequently, common typesAof heating equipment.are usually designed, installed, and adjusted to operate with some excess air. The exact percentage of such air depends on the type of fuel being utilized, as well as anticipated variations in its quantity^ and quality. Despite these practical limitations, however, it should not; be inferred that common types of fuels cannot be utilized economical}^ Reference to flue loss charts such as Figs. 6 and 7 for gas burning equipv ment and to the air requirements discussion in Chapter 15 shows that- reasonable quantities of excess air can be used without appreciable reduc tions in operating efficiencies. 'Cfi Oxygen combines with the combustible elements and compounds of. spfj fuel in accordance with fixed laws. The reactions and resultant product^ of perfect combustion of common fuel constituents are set forth in Tablfe:'t; All of the oxygen required for combustion is normally obtained from-^i surrounding air, which is a mechanical mixture of nitrogen and oxygen rgjk small amounts of carbon dioxide, water vapor and inert gases. For pra^; tical combustion calculations, air is considered to consist of 20.9 per};?! oxygen and 79.1 percent nitrogen by volume, and 23.15 percent oxygf, and 76.85 percent nitrogen by weight. The nitrogen, being inert; pa&9S| through the reaction without change. Table 7 gives the air quantifi^, corresponding to the oxygen required for perfect combustion. lj Air supplied to the combustion reaction is in most instances introdj|Cpj in two ways. Primary air is introduced through or with the fuel,?,^ secondary air is supplied to the flames issuing from the fuel. : Incomplete combustion is obtained when any of the combustible, elefnef1,-; are not completely oxidized in the combustion reaction. This condiw,. Fuels and Combustion combustion, n or example, a hydroc,,ar--bo--n mmawy noptroodxuidciztse ocof minpcloemteplylett(i carbon dioxide and water, as indicated in Table 7, but may also form al cohols, ketones, aldehydes, or carbon monoxide depending on where and how the reaction is interrupted. 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 %ccv ^ EXCESS. A(ft IN FLUE GASES ttf Z 2 if f% EXCESS JUR , xco IN FLUE CASES SF *1 * Flue .LOSS . BUTANE and PROPANE a oq-L . .I . Adapted from American Gas Association Laboratories Fine Loss Charts. - Fig. 7. Alignment Chart tor Calculation of Flue Losses for Butane, Propane, Coke Oven, and Natural Gases by products of combustion not properly vented), or insufficient mixing oi 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 complete combustion of a unit of fuel 18 constant for a given combination of combustible elements and com pounds, and is known as the heat of combustion, calorific value, or healing wane of the fuel. The heat of combustion of the several substances found w the more common fuels is given in Table 7. : The calorific value of a fuel may be determined either by direct measure ment 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 chemical elements in the fuel. When the heating value of a fuel I* determined in a calorimeter, the water vapor is condensed and the latent eat of vaporization is included in the heating value of the fuel. The heat- Fuels and Combustion 347; ing value so determined is termed the gross or higher heating value, and this is what is ordinarily meant when the heating value of a fuel is specified. In burning the fuel, however, the products of combustion are not cooled to the dew-point and the higher heating value cannot be .utilized. When combustion is complete, the carbon in the fuel unites with oxygen to form carbon dioxide, C02, the hydrogen unites with oxygen to form water vapor, //20, and the nitrogen, being inert, passes through the re action 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 burned at all. When carbon monoxide or other combustible gases are present in the flue gases, there is a loss of heat produced per unit of fuel consumed, and a lower ' combustion efficiency is obtained. Incomplete combustion may result from any or all of the following three conditions: (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 similar 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 substitution 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: . _ 34.56 Pounds air required per pound fuel c- + (h-) + s " 100 3 \ 8/ 8 For Gaseous Fuels: Cubic feet air required per cubic foot gas = 2.39 (CO + Hi) + 9.53 CHt + 16.68 C,H6 + 23.82 C,H, + 30.97 C,Hio + 11.91 CiHt + 14.29 C,/7, + (3) 7.15 HiS - 4.78 0, + 30.47 Illuminants Gaseous fuels may contain a wide variety of components classified as uluminanls, which are not separated by the usual methods of gas analysis. I he principal ones in addition to ethylene and acetylene which are included 'n 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 lor a fuel gas. An approximate value of 30.47 (as shown in Equation 3) therefore, be employed. If ethylene and acetylene are included as Ruminants, it is suggested that the value 19.65 be used. If it is desired to make the gas calculations on a weight basis the equation " exPressed as follows: founds air required per pound fuel = 2.47 CO + 34.34 Ht + 17.27 CHt + 16.12 C,H* + 15.70 CJis + 15.49 C,H,,, + 13.30 C2Ht + . 14.81 CtH, -f 6.10 HS - 4.32 0, (4) .Where1 approximate results only are desired,'values appearing 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 om the subject of combustion and related topics-by the various industries concerned. If approximate values for the oretical air requirements suffice, or if complete information on the fuel is not available, the following values should also be found helpful: 1; Solid Fuels (Pounds air per pound fuel); Anthracite, 9.6; Semi-Bituminous, 11.2; Bituminous 10.3; Lignite 6.2; and Coke 11.2. ' . .. ... . Table 8. Approximate Aik Requirements fob Theoretically Perfect ....... Combustion of Fuels* . Type . OF Fuel Mb Required fob Perfect Combustion Lbe per Lb Fuel Cu Ft per Unitb Fuel Appboxi- mate Preci sion, ; Peb Cent Exceptions Solid Btu per lb X 0.00073 Btu per lb X 0.0097 .. 3 Liquid Btu per lb X 0.00071 Btu per lb X 0.0094 3 Gas Btu per lb X 0.00067 Btu per cu ft X 0.0089 5 Fuels containing . .. more than 30%'. 5 water '! f [ Results: low fai-y gasoline and kerosene Gases of 300 Btu ' per cu ft or] less . 4 Values in table taken from page Y/o ot oaseoiw r we*o, mo, FUq,WUVv. ^ Units for solid and liquid fuels in pounds, for gas in cubic feet. _______ `> 2. Fuel Oil (Pounds air per gallon): Commercial Standard No. 1, 102.6; No. 105.5; No. 5, 112; No. 6, 114.2. `, "4 3. Gaseous Fuels (Cubic feet of air per cubic foot): Natural, 10.0; Mixed Natural;^' and Manufactured, 8.0; Manufactured, 4.7, Propane, 23.8, Butane, 31.0. 4 COMBUSTION EFFICIENCY FROM THE FLUE GAS ANALYSIS (5 Excess Air . . &. A commonly employed index of efficiency of combustion is the relation;vv existing between the amount of air theoretically required for perfect cora-/` bustion and the amount of air actually supplied. Since the difference^ between air supplied for combustion and theoretical air required is charact^f terized as excess air, its percentage may be calculated by use of the follow-g' ing equation, Percent excess air -(S plied - Theoretical air\ x Theoretical air J (5)/. , gf ' The amount of dry air supphed per pound of fuel burned may be from Equation 6 which has reasonable precision for most solid and ... ; TV fuels.. Values for CO2, CO and are percentages by volume from the fluf gas analysis, and C is the weight of carbon burned per pound of fuel, cor-. rected for carbon in the ash. .' tv'? Pounds dry air supplied per pound of fuel = (CO, -- + CO) x C .jS^* Because excess air calculations are almost invariably made from OrsaJ- s >w* Fuels and Combustion 349 analysis results, and theoretical air requirements are not always .known, another convenient method of expressing the relation of Equation 5 is as follows: . Percent excess air = 100(0, - CO/2); N, X 0.264 - (O, - CO/2) (7) As measurement standards for gaseous fuels are almost universally ex pressed in cubic feet, Equation 8 may be employed for computing excess air on a percentage basis for gases.21 where Percent excess air = (U - CO,) CO, X P 100 - A (8) U = ultimate carbon dioxide, percent of flue gases resulting from perfect com bustion. CO, = 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 - 'p ' ' ': 90 may be substituted for TOO -r in Equation 8 for rough calculation. > : . ,. ; : A. . . - . Carbon-hydrogen ratios of different fuels vary considerably, hence the maximum or ultimate attainable also varies. Where they, are un known, theoretical maximum CO2 values.may be calculated from a flue gas analysis by use of Equation 9.' ; .. Maximum theoretical % CO, = % co*ln due gas sample X 100 (!100 O, in same sample^ 0.21 (9) Approximate maximum CO2 values for perfect combustion1 of several common types of fuel are shown in Table 9 together with values of CO2 that will be attained with different amounts of excess air. Desirablevalues 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 oasic requirements must be met: .(1) adequate heat absorbing surface of proper shape and construction is necessary in the appliance, (2) heat trans fer 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 mixed, and (5) flue gas losses must be reduced to a safe minimum. If insufficient heating surface is employed, or if heat transfer surfaces 3re 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 uiuch excess air dilutes flue gases excessively and increases sensible flue Sas loss. On the other hand, a deficiency of excess air will in all probability oause incomplete combustion, and some of the combustible gases will,pass rdni the appliance without being completely burned. Highest combus- 350 CHAPTER 14 1954 Guide tion efficiency is not always obtained when sufficient excess air is supplied to eliminate incomplete combustion entirely, because the air supply must not only be adequate but also be properly mixed with the combustible gases. Even with appliances connected to an effective flue every reason able precaution should be taken to insure 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 common types of central heating appliances are largely employed 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 considerations and others indicate not only the desirability but absolute necessity of a reasonably accurate method for determining flue losses if it is desired to compute even approximate operating efficiencies. Customary procedure in arriving at flue gas losses is to make an anlysis 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. CarboD ; dioxide and oxygen content are of principal interest in determining flue ; losses. Either or both of these values may be employed in such calcula- tions. While the former constituent is probably most commonly employed, special considerations may make the latter of greater interest. Fortun ately, both can be determined readily by use of an Orsat gas analysis ap- / paratus, 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 Chapter 51 for details regarding the A operation of the Orsat apparatus. + The weight of dry flue gas per pound of fuel burned is widely used in* combustion loss calculations. For solid fuels this item may be determined by application of Equation 10. . -f Pounds dry flue gas per pound fuel 11C0, + 8Q, + 7(C0 + A,) 3(00,+ CO) (30) Values for CO2 O2, CO, and iV2 are percentages by volume from the fluer? gas analysis, and C is the weight of carbon burned per pound of fuel, cofc-yt rected for carbon in the ash. Total dry gas volumes of flue gases resulting from the combustion ow one cubic foot of gaseous fuels for various percentages of CO2 may be deter-V mined by application of Equation 11: :: : Cubic feet dry flue gases per cubic foot fuel gas = Cubic feet CO, produced per cubic foot of gas burned X 100 Percent CO, by analysis. (llp, After obtaining the quantity of flue gases from Equations 10 or 11, excess air quantity may be determined by subtracting the quantity of Fuels and Combustion 351 flue gases which would result from perfect combustion. Computations of flue losses are described in the next section on Heat Balance. ', Application of the preceding equations and tables are illustrated by Ex amples 1 and 2. Example 1: The analysis of the flue gases resulting from the burning of a natural gas is 10.0 percent CO,, 3.1 percent 0,, and 86.9 percent A , by volume. The analysis of the fuel is 90 percent CH,, 5 percent A',, and 5 percent CzHt by volume. Find U the maximum theoretical percent CO, and the percent excess air. , Solution: From Equation 9: 3.1 > From Equation 8, = N -8% CO, 0.2l) U = (lOO)UOO) P,,ercent E,,xcess A..ir = (-1--1--.8--------1--0--.0--)--X----9--0 = 16.2 - 10 Example 2: For the analyses in Example 1 find, per cubic foot of fuel gas, the cubic feet of dry air required for combustion, the cubic feet of each constituent in the flue gases, and the total volume of dry and wet flue gases. Solution: From Equation 3 (or Table 7) the volume of dry air required for combus tion is: (9.53) (CH,) + (16.68)(Ci/Te) = 9.53 X 0.90 + 16.68 X 0.05 = 9.41 cu ft/cu. ft gas. From Table 7, the constituents per cubic foot of gas are: Nitrogen, A,: From methane = (0.9 CH,)(9.53 -- 2.0) - 6.78 From ethane = (0.05 C,ff,)(16.68 - 3.0) = 0.68 Total Nitrogen Nitrogen in fuel 8.71 cu ft 0.05 Nitrogen in excess air = 0.791 X .162 X Oxygen, 0,: Oxygen in excess air = 0.209 X .162 X 9.41 = 0.32 cu ft Carbon dioxide, CO,: From methane = (0.9 Cff,)(1.0) = 0,90. From ethane = (0.05 C,#,)(4.0/2.0) = 0.10 Total Carbon Dioxide 1.00 cu ft Water vapor, H,0 (does not appear in Orsat analysis): (0 9 CH,) (2.0) =1.8 (0.05 C,Ce)(6.0/2.0) = .15 , Total water vapor = 1.95 cu ft Total volume of dry gas per cubic foot of gas: fiojf'ai4) vo'ume f weI- gas8e.s71pe+r c0u.3b2ic+foo1t.0o0f g=as10(n.0e3gcleucftitng water vapor in combus- pFeqnT,,ua0h,etioccnuhbIiiIcc affeeseefttoollof dwrsy: f"lue g1a0s.0p3er+cu1b.9ic5 fo=ot11o.f9f8uceul gfats may also be computed from (1 00) (100) Wo 10.0 cu ft to^eJisual practice in analHyzEinAgTthBeApLeArfNorCmEance of heating appliances is unit1TM6 an accounting, insofar as possible, of the disposition of all heat ts available in the quantity of fuel burned. This accounting is called Table 9. Approximate Maximum Theoretical CO; Values, and CO; Values for Various Fuels with Different Percentages of Excess Air .' /. Type op Fuel Maximum THEORETICAL OB Ultimate Percent COt Pebcbst CO, AT GIVJN Etceab Alt VAI.UAA Coke Anthracite Bituminous Coal No. 1 and 2 Fuel Oil No. 6 Fuel Oil Natural Gas Carburetted Water Gas Coke Oven Gas Mixed Gas (Natural and Carbu retted Water Gas) Propane Gas (Commercial) Butane Gas (Commercial) 21:0 20.2 18.2 15.0 16.5 12.1 17.2 11.2 15.3 13.9 14.1 i heat balance. Various components of this balance are generally expressed 0 ii terms of Btu per pound of fuel burned, or as a percentage of its calorific \rahie. Components of special interest are listed as items 1 to 7 inclusive: . a1b.leU. seCfuol hmepaot ntreanntssfeorrfesdpteoci-hael amtinmg -mC--Oe--lld1 CiuL*mL. ,Aus~ually . computed by determining aa:.;-i! the rate of flow of the beating fluid through the heating device, and the change in enthalpy of the fluid (heat added) between the inlet and outlet. "j|?F 2. Heat loss in the dry chimney gases. ' *1 = U)gCp (te - i.) 3. Heat loss in water vapor formed by the combustion of hydrogen. 9H, h, = -- (1089 ' 100 t, -p 0.455 f,) 4. Heat loss in water vapor in the air supplied for combustion. hi = 0.455 M (I, -- i.) - 5. Heat loss from incomplete combustion. h, = 10143 C ( -x~--~r ) \CO; + CO.) 6..Heat loss from unburned carbon in the ash or refuse. . A- 1460*(S-C) (i3)/.:% . 7. Radiation and all other unaccounted for losses. Radiation and convection losses from a heating appliance are not visually deter mined by direct measurement. For this reason they, together with any other loss not measured, are determined by subtracting the total of items 1 to 6 from the hSS, of combustion of the fuel. If the heating appliance is located within the heate? space, however, radiation and convection losses may be. considered as useful P? rather than lost heat. They may, therefore, be omitted from calculations of A value of 14600 applies in calculating ach pit !oea; in calculating heat of formation of carbon comport use 14093 Btu pgr lb . .. ^ Fuels and Combustion 353 losses, or added to item 1. If there is CO in the flue gases, small amounts of, un burned hydrogen and hydrocarbons will probably also Be present. The small loses due to incomplete combustion of these latter gases would also be included in item 7. Symbols used in Equations 12 to 16 inclusive arc: ' : hi = heat loss in the dry chimney gases, Btu per.pound of fuel. h; = heat loss in water vapor from combustion of hydrogen, Btu per pound of fuel. ,, : Aj = heat loss in water vapor in combustion air, Btu per pound of fuel. hi = heat loss from incomplete combustion of carbon, Btu per pound of fuel. ht = heat loss from unburned carbon in the ash, Btu per pound oi fuel i i wt = weight of dry flue gas per pound of fuel (from.Equation 10), pounds.1 cp = mean specific heat of flue gases at constant pressure (cp ranges from 0.242 toO.254 for flue gas temperatures from300F to 1000 F)*, Btu,per pound. tg == temperature of flue gases at exit'of heating device', Fahrenheit. , U = temperature of combustion air,-Fahrenheit. ; ! Ht = percentage of hydrogen in fuel by weight from ultimate analysis of fuel burned. , . . ,. ... 1091.8 = enthalpy of saturated water vapor at a temperature of 70 F, Btu per ' pound, '' .. ' '' '' ' ' ' " M - humidity ratio of combustion air, pounds of water vapor per pound ot dry air. ,' is. -- 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 corrected for carbon'in ash, pounds. WC\ - W.C., C .100 IF (17) where Ca = percentage of carbon in the fuel-by weight from the ultimate analysis. , 1F,, = weight of ash and refuse, pounds. ; C, = 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 sufficient precision for most purposes from curves shown in Fig. 62, if CO% content and temperature of flue gases are known. Values of the losses plotted for fuel oil were com puted 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 negligible error. 1' ' Utilization of gaseous fuels, for numerous reasons, is generally a more sim ple 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 m that items 5 and 6 do not generally apply to gas installations. A series of typical alignment charts has been combined in Fig. 7 for use in determin ing fine losses of items 2, 3 and 4 from common types of gas burning appli ances. : To determine flue losses place a straight edge extending from the Corrected temperature reading to the percent COt recorded. Percent flue *9ss is indicated where the straight edge interesects the flue loss column.  354 CHAPTER 14 1954 Guide mi ft 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\ gas per cubic foot/ ycubic foot fuel gas)/ ^ ^ Gross Btu of fuel gas per cubic foot Reference to Table 9 will show that ultimate CO2 percentage values of fuel gases vary. While personal errors involved in CO2, 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 information the reader is referred to Combustion, 3rd Edition, and Gaseous Fuels, (published T by American Gas Association) and particularly to tables covering various properties of different commercial gases included in these publications. CONDENSATION AND CORROSION J Sulfur dioxide or sulfur trioxide, formed by the combustion of sulfur in V fuels, are the principal corroding substances in flue gases. They become } active whenever sufficient moisture is present for the formation of sulfurous or sulfuric acid,22 and they lower the dew points of flue gases appreciably. ? Therefore, unless heating equipment is designed for operation at flue gas J temperatures below the dewpoint, which is seldom the case, it is always ad- t visable to maintain temperatures above this value in all parts of the ap- > pliance. Excessive spot temperatures in the combustion chamber or else- v where, on the other hand, are also destructive in that they may result in j| rapid oxidation of ordinary heating surfaces. American Standard Require ments for gas furnaces, floor furnaces, and recessed heaters, for example, specify that minimum spot heating surface temperatures during normalv ' operation must neither fall below 178 F (50 F above average dewpoint) ,^ nor exceed 875 F on any portion of the heating surface. In any event/ it is usually desirable to maintain flue temperatures within the limits in- 7 dicated not only throughout the appliance, but in its connecting vent, -; flue, or chimney as well. Otherwise, excessive condensation and corrosion-i problems, with resultant customer dissatisfaction, will in all probability be the result. Average dewpoint temperatures of flue gases 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- I soot ;f 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. 327??", shows that the loss of seasonal efficiency is not so great as has been be- ` lieved, and usually is not over 6 percent because the greater part of the,; heat is transmitted through the combustion chamber surfaces. The? Bureau of Standards Report BMS 5424 points out that, although the dfci crease 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 P1^"; vent proper combustion. Soot can probably be most effectively renovgf. by a jet of compressed air, by means of a brush, or a vacuum eleape^' However, it has been found that copper chloride, lead chloride, tin chlorides' zinc chloride, common salt and some other salts are partially effective U'/j, '?. s Fuels and Combustion 355 T YPE OF I' UKl. Anthracite................... Semi-Bituminous Coal Bituminous Coal Oil....................... "" Natural Gas.......' ' ' Manufactured Gas Propane Gas (2500 Btu/cu ft) Butane Gas (3200 Btu/cu ft) Butane-Air Gas Mixture (535 Btu/cu ft Average Dew-Point t emperature, F 68 84 93 111 127 137 119 124 121 removing soot from furnaces and boilers when properly used.25 A discus sion of instruments and methods of evaluating smoke will be found in Chapter 51. . * REFERENCES 1 Five Hundred Tests of Various Coals in Househeating Boilers (U. S. Bureau of Mines Bulletin No. 276). , * Combustion Efficiencies as Related to Performance of Domestic Heating Plants, by A. P. Kratz, S. Konzo and D. W. Thompson ( University of Illinois, Engineering Experiment Station Circular No. 44)- ' ' *' * Quality of Anthracite as Prepared at Breakers, 1935 {U. S. Bureau of Mines Re port of Investigation, R. I. 3283). .. * Hand Firing Soft Coal Under Power Plant Boilers (U. S. Bureau of Mines Tech nical Paper No. SO). * Combustion Flames and Explosions of Gases. Lewis and von Elbe (Cambridge University Press, 1938). 6 Oil Burning, by H. A. Romp (Martinus Nijhoff, 1937). 7 ASTM Test Designation D287-39. 8 ASTM Test Designation D611-43T. .. 9 Tomorrow's Fuel Oil, by W. A. Sullivan and E. B. Glendenning (Fueloil and Oil Heat, Vol. 4, No. 3. May 1945 p. 36). 10 The Correlation of Cetane Number with Other Physical Properties of Diesel Fuels (Journal of the Institute of Petroleum, Vol. 30, 1944, p. 193-197). 11 Characterization of Petroleum Fractions, by K. M. Watson, E. F. Nelson and G- B. Murphy (Industrial and Engineering Chemistry, Vol. 27, Dec. 1935, p. 1464). " Burning Index for Distillates, by J- C. Reid and A. B. Hersberger. Fueloil and Oil Heat, Vol. 5, No. 9, Jan. 1947, p. 90). u Carbon Hydrogen Ratio of Catalytically Cracked Distillate Fuel Oils, by S. P. Cauley and E. B. Delgass (The Oil and Gas Journal, Vol. 45, No. 12 July 27, 1946, p. 166). u Rating of Fuel Oils by a Test Unit, bv D. W. Locklin and G. V. Parmelee (ASHVE Transactions, Vol. 57,1951, p. 139). 16Caseous Fuels (American Gas Association, 1948, p. 32). u Gas Analysis and Testing of Gaseous Materials by V. J. Altieri (American Gas Association, First Ed. 1945). ''Tentative Methods of Test for Specific Gravity of Gaseous Fuels (American society for Testing Materials, ASTM Designation1070-49). 18 Standard Method of Test for Calorific Value of Gaseous Fuels by the WateryUU-48C). alorimeter (American Society for Testing Materials, ASTM Designation: u American Standard for Installation of Gas Piping and Gas Appliances in BuildnSs. ASA Z 21.30 1950 (American Gas Association). "MFU Standard for the Installation of Oil Burning Equipments--NBFU pam . no- 31 (National Board of Fire Underwriters). 7 P^cstic Gas Range Research (American Gas Association Laboratories Bulletin fP- 64). CHAPTER 14 . 1954 Guide. 356 28 Condensation of Moisture in Flues, by William R. Morgan (University of Illi noi2s3, EEfnfegcint eoef rSinogotEoxnpeHreimaet nTtraSntsamtioisnsiConircinulaBroNileor.s 2(2U).. S. Bureau of Mines Report of Investigation No. 3272). ^ u Effect of Soot on the Rating of an Oil-Fired Heating Boiler (National Bureau of Standards Report BMS 54), ' 24 Removal of Soot from Furnaces and Flues by the Use of Salts and Compounds, by P. Nieholls and C. W. Staples (U. S. Bureau of Mines Bulletin No. 360). bibliography Fuels and Their Combustion, by Haslam and Russell (McGraw-Hill Co., 1926). Principles aj Combustion in the Steam Boiler Furnace, by Arthur D. Pratt (Bab cock and Wilcox Co.). . . .. Smoke-Producing Tendencies in Coals of Various Ranks, by H. J. Rose and F. P. Lasseter (A.S.H.V.E. Transactions, Vol. 45, 1939, p. 329). Fundamentals of Combustion in Small Stokers, by C. A. Barnes (Bituminous Coal ResHeaarncdh,-FInircin.,g ToefcBhintuicmalinRoeupsorCt oNaol i.nIVth)e. Home, by A. P. Kratz, J. R. Fellows, . and; J. C. Miles (Illinois Engineering Experiment Station Circular No. 46). Classification and Selection of Illinois Coals, by G. H. Cady (Illinois Slate Geo logical Survey Bulletin No. 62). , Bituminous Coal Research, Inc.: ' Technical Report VI, The Treatment of Coal with Oil and Other Petroleum Prod;,, ucts, by J. M. Pilcher and R. A. Sherman. ;. 7 Information Bulletin No. 4, Dustless Treatment of Coals with Materials Other' Than Oil, by R. A. Sherman and G. W. Land. - , Information Bulletin No. 6, Questions and Answers on the Use of Fuel Oil for Dust lTeesschTnriecaaltmReepnot.rt VII--Application of Overfire Air Jets, by R. B. Engdahl. Bureau of Mines Publications: "' Bulletin No. 97, Sampling and Analyzing Flue Gases, by Henry Kreisinger and; FR.epKo.rtOovfitIzn.vestigations (R. I. 2980), Coke as a Domestic Heating Fuel, by P: - NTeiechhonlilcsaal nPdapBe.rAN. oL.a3n0d3r,yV. alue of Coke, Anthracite, and Bituminous Coal for' Generating Steam in a Low-pressure Cast-Iron Boiler, by John Blizard, James. Neil, and F. C. Houghten. Bulletin 378, Effect of Preheat, and Distribution of Ash in Fuel Beds; by. P. Nieholls. 'f Handbook, Questions and Answers for the Home Fireman (Revised), by J. F. ' Barkley. 0 Anthracite Industries LaboratoriesPublications: Report 2015, Comparison of Sizes, Egg,Stove and Chestnut Anthracite. j " Report 2018, Domestic Survey. Report 2062, Utilization of Anthracite for Domestic Heating. Report 2204, The Crater Method of Firing. Report 2403, Anthracite Industries Manual. Oil and Gas Publications: - Oil Fuels and Burners, by Janies A. Moyer (McGraw-Hill Co., 1937). Industrial Gas Series, Combustion (American Gas Association). Comfort Healing (American Gas Association). 'V . .:. . ?t GHaasnedobuosoFkuoeflsO(iAl Bmuerrnicianng,Gbasy AFs.sHo.ciFaatiouns,t 1a9n4d8)G. . T. Kaufman (Oil-Heat Institutei oFof rAmmuelarsicaa,nd19G5r1a).phs for Representing the Interchangeability of Fuel Gases, by^-j Elmer R; Weaver (National Bureau of Standards Journal of Research, 1951, Re~'i, search Paper R.P. 2193). 1 CHAPTER IS 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; Oil Storage Tanks and Piping; Classification of Gas-Fired Heating Equipment, Combustion Process, Ratings; Sizing of Gas : Piping, Fuel Burning Rates AUTOMATIC mechanical equipment for the combustion of solid, liquid, L and gaseous fuels is considered in this chapter. MECHANICAL STOKERS A mechanical stoker is a device that feeds a solid fuel into a combustion chamber, provides a supply of air for burning the fuel under automatic control and, in some cases, incorporates a means of removing the ash and refuse of combustion 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 the air supplied for combustion. Classification of Stokers According to Capacity Stokers may be classified according to their coal feeding rates. The following classification has been made by the U. S. Department of Com merce, in cooperation with the Stoker Manufacturers Association. Class 1. Capacity under 61 lb of coal per hour. Class 2. Capacity 61 to 100 lb of coal per hour. Class 3. Capacity 101 to 300 lb of coal per hour. Class 4. Capacity 300 to 1200 lb of.coal per hour. Class 5. Capacity 1200 lb of coal per hour and over. Class 1 Stokers These stokers are used primarily for home heating and are designed for quiet, automatic operation. Simple, trouble-free construction and attrac tive appearance are desirable characteristics 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 to the retort, a fan which supplies the air for combustion, 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 rectangular. Stokers in this class are made for burning anthracite, bituminous, semi-bituminous, and ugnite coals, and coke. The U. S. Department of Commerce, has. issued commercial standards for household anthracite stokers.1 . ., , Uuits are available in either the hopper type, as shown in. Fig. 1, or in me bin-feed type as. shown in Figs. 2 and 3. Some stokers, particularly nose designed for use with anthracite, automatically remove ash from ne ash pit and deposit it in an ash receptacle as shown in Fig. 3. Most 357 of the bituminous models, however, require 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. Where year-round domestic hot water is supplied by a boiler and indirect water heater connected to a storage tank, the stoker will usually be called on to operate often enough to maintain the fire. Stoker-Fired Boiler and Furnace Units Boilers, air conditioners, and space heaters especially designed for stokers are available having design features closely coordinating the heat absorber and the stoker. Although efficient and satisfactory performance can be obtained from the application of stokers to existing boilers and A- Fig. 1. Underfeed Stoker, Hopper Type, Class 1 -A J .'I Fig. 2. Underfeed Stoker, Bin Feed Type, Class 1 furnaces, some of the combination stoker-fired units (Fig. 4) are compact and attractive in appearance. Class 2 and 3 Stokers Stokers in this class are usually of the screw feed type without auxiliary-^ plungers or other means of distributing the coal. They are used exten-|s: sively for heating plants in apartments and hotels, also, for industrial,^ plants. They are of the underfeed type and are available in both the bP(j?, per .type, as illustrated in Fig. 5, and the bin feed type, shown in Fig'.-$y These units also are built in plunger feed type with an electric motor a steam or hydraulic cylinder coal feed drive. Stokers in this class are available for burning all types of anthracite' -- bituminous and lignite coals. The tuyere and retort design varies accort .. ing to the fuel and load conditions Stationary type grates are used on; bituminous models, and the clinkers formed from the ash accumulate on,' the grates surrounding the retort. Vj Anthracite stokers in this class are equipped with moving grates wluc Automatic Fuel Burning Equipment 359 discharge the ash into a pit below the grate. This ash pit may be located on one or both sides of the grate and, in some installations, is of sufficient capacity to hold the ash for several weeks' operation. Class 4 Stokers Stokers in this group vary widely in details of design, and several methods of feeding coal are employed. The underfeed stoker is widely used, al though a number of the overfeed types are used in the larger sizes. Binfeed, as well as hopper models, are available in both underfeed and overfeed types. Class 5 Stokers The prevalent stokers in this field are: (1) underfeed side cleaning, (2) underfeed rear cleaning, (3) overfeed flat grate, and (4) overfeed inclined grate. Underfeed side cleaning stokers are made in sizes up to approximately 500 boiler horsepower. They are not so varied in design as those in the smaller classes, although the principle of operation is similar. A stoker of this type is illustrated in Fig. 7. The rear cleaning underfeed stoker is usually of the multiple retort design, and is used in some of the largest industrial plants and central power stations. Zoned air control has been applied to these stokers, both longitudinally and transversely of the grate surface. The overfeed flat grate stoker is represented by the various chain--or traveling-grate stokers. A typical traveling-grate stoker is illustrated in Fig. 8. Another distinct type of overfeed flat-grate stoker is the spreader (Figs. 9 and 10) type in which coal is distributed either by rotating paddles or by air over the entire grate surface. This type of stoker is adapted to a wide range of fuels and has a wide application on small sized fuels, and on fuels such as lignites, high-ash coals, and coke breeze. The overfeed inclined-grate stoker operates on the same general com bustion principle as the flat-grate stoker, the main difference being that rocking grates, set on an incline, are provided in the former to advance the fuel during combustion. Combustion Process In anthracite stokers of the Class 1 underfeed type, burning takes place entirely within the stoker retort. The refuse of combustion spills over the edge of the retort into an ash pit or receptacle from which it may be removed either manually or automatically. Larger underfeed anthracite stokers operate on the same principle, except that the retort is rectangular and the refuse spills over only one or two sides of the grate. Anthracite for stoker firing is usually the No. 1 buckwheat or No. 2 buckwheat size. Because the majority of the small bituminous coal stokers operate on we underfeed principle, a general description of their operation is given, when the coal is fed into the retort, it moves upward toward the zone of combustion and is heated by conduction and radiation from the burning m the combustion zone. As the temperature of the coal rises, it fy(es off moisture and occluded gases, which are largely non-combustibles. hen the temperature increases to around 700 or 800 F the coal particles come plastic, the degree of plasticity varying with the type of coal. 360 CHAPTER 15 Automatic Fuel Burning Equipment 361 Fig. 3. Underfeed Anthracite Stoker with Automatic Ash Removal, . Bin Type . Fig. 6. Underfeed Screw Stoker, Bin Type, Class 2, 3 or 4 Feed saw--> Fig. 4. Stoker-Fired Winter Air Conditioning Unit A rapid evolution of the combustible volatile matter occurs during-and; directly after the plastic stages The .-distillation of volatile matter--cc^tinues above the plastic zone where the coal is coked. The strength apn^ porosity of the coke formed will vary according to the size and characters^ istics of the coal.- While some of the ash fuses into particles on the surface) of the coke as it is.released, most of it remains on the hearth or grates anflfev as this ash layer :becomes thicker with time, that portion exposed to tfewc higher temperatures surrounding the retort fuses into a clinker. !!!>!;. jBperature in the fuel bed, the chemical composition and homogeneity e ash, and the time of heating govern the degree of fusion. - st bituminous coal stokers of Classes 1, 2, 3 and 4 require manual Val of the ash in clinker form. 362 CHAPTER IS 1954 Guide In the underfeed side-cleaning stokers the fuel is introduced at the front, of the furnace to one or more retorts, and is advanced/away from thej retort as combustion progresses, while finally the ash is disposed of at the sides. This type of stoker is suitable for all bituminous coals, while in the I 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 volatile gases are released, are mixed with air, and pass through the fire where they are burned. The ash may be con tinuously or periodically discharged at the sides. The underfeed rear-cleaning stoker accomplishes combustion in much the same manner as the side-cleaning type, but consists of several retorts placed side by side and filling up the furnace width, while the ash disposal is at the rear. In principle, its operation is the same as the side-cleaning^ underfeed type. . Overfeed flat-grate stokers receive fuel at the front of the grate in a Automatic Fuel Burning Equipment 363 as to maintain a balance between the load demand and the heat liberated by the fuel. Under such conditions, no manual attention to the fuel bed should be required 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 burn 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 re sistance. 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 resistance, many bituminous stokers, even in the smaller domestic sizes, incorporate air controls which automatically com- layer of uniform thickness and move it horizontally to the rear of the furnace. Air is supplied under the moving grate to carry on combustion. at a sufficient rate to complete the burning of the coal near the rear of the furnace. The ash is carried over the back end of the stoker into an asb pit beneath. This type of stoker is suitable for small sizes of anthracite or coke breeze, and also for bituminous coals, the characteristics of which make it desirable to bum the fuel without disturbing it. This type of stoker requires an arch over the front of the fuel bed to maintain ignition of the incoming fuel, and frequently a rear combustion arch. - In addition to the use of rocking grates, the overfeed inclined-^3**, stoker is provided with an ash plate on which ash is accumulated dumped periodically. This type of stoker is suitable for all types df cokinS* fuels, but preferably for those of low volatile content. Its grate action keeps the fuel bed broken up, thereby allowing free passage of air. Because of rt*: agitating effect on the fuel, it is not desirable for badly clinkering coals. 1". usually should be provided with a front arch to ignite the volatile gases.-^ 'Vi* Combustion Adjustments supply to the stoker should be regulated;!|| The coal feeding rate and air Fig. 10. Overfeed Spreader Stoker (Pneumatic Type) pensate for these changes in resistance and maintain a constant air fuel ratio. The efficiency of combustion may be determined by analyzing the flue gases, 33 explained in Chapters 14 and 51. It is desirable on most stoker installations to provide automatic draft regulation in order to reduce air infiltration and provide better control during the banking, or off, periods of the stoker. Furnace Design Although there is considerable variation in stoker, boiler, and furnace design, the stoker industry, from long-time experience, has established certain rules for the proportioning of furnaces for domestic and com mercial stokers. The stoker installer and designer of stoker-fired equip ment should give careful consideration to these factors. The Stoker Manufacturers Association has published standard recom mendations on setting heights for stokers having capacities up to 1200 lb of coal per hour.2 The empirical formulas for determining these setting heights are: For burning rates up to 100 lb coal per hour H = 0.1125 B + 15.75 (1) ,364 CHAPTER 15 1954 Guide For burning rates from 100 to 1200 lb coal per hour H = 0.03 -F 2( "her* H = minimum setting height, inches, measured from dead plates to crown sheet for steel boilers. For cast-iron boilers height may be l 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. 11.5 In considering these recommendations, it should be understood 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 certain instances, setting height or firebox dimensions shown in the standards may be modified without impairing performance. Such modification will depend upon the experience of the installer or de- Automatic Fuel Burning Equipment 365 or hot water heating system, a piping and pick-up factor of 1.33 is com monly used in sizing the stoker, but this factor should be increased attimes due 'to unusual conditions. Controls .. The heat delivery from the stoker of the smallest household type to the largest industrial unit can be regulated accurately with fully automatic controls. The smaller heating applications are controlled normally by a thermostat placed in the building to be heated. Limit controls are supplied to prevent excessive temperature or pressure from being developed in tha furnace or boiler, and refueling controls are used to maintain ignition during periods of low heat demand. Automatic low water cut-outs are recom mended for use with all automatically-fired steam boilers. (See Chapter 39.) . . DOMESTIC OIL BURNERS An oil burner is a mechanical device for producing heat automatically from liquid fuels. Two methods are employed for the preparation of the Fig. 11. Suggested Minimum Firebox Dimensions and Base Heights* * For reference in selecting or designing boilers and furnaces for stoker firing. Dimensions shown are for net inside clearance at grate level usin com with heating value of not less than 12,000 Btu per pound. Under certain conditions smaller fireboxes will permit satisfactory performance but these dimensions are preferred normal minimums. . , . , . signer with a particular stoker, the type of fuel used, and the construction of Itnhsetablolailteior norofuf rnstaockee.rs (particularly smaller sizes) on the side of , the. boiler or furnace will sometimes facilitate clinker removal. . -ii;... Rating and Sizing Stokers A The capacity or rating .of small underfeed stokers is usually stated as. the burning rate in pounds of coal per hour. Codes for establishing uni; form methods of rating anthracite and bituminous coal stokers have beea adopted by the Stoker Manufacturers Association.1 ''!iff The Association also has adopted a uniform method of selecting stoker^ that is published in convenient tables and charts.' The required capacity of the stoker is calculated! as follows: Stoker burning'r*1 Load (Btu per hour) = required (pounds ? ' Heating value of coal (Btu per pound) X overall efficiency of coal per hour) ( _i.-J stoker and boiler or furnace In determining the total load placed on a stoker-fired boiler by a stev. Fig. 12. High-Pressure Atomizing Oil Burner . oil for the combustion process; atomization, and vaporization. The simpler types of burners depend upon the natural chimney draft for supplying the air for combustion. Other burners provide mechanical air supply or a combination of atmospheric, and mechanical. Ignition is accomplished by an electrical spark or hot wire, or by an oil or gas pilot. Some burners utilize a combination of these methods. Continuously operating burners may use manual ignition. Burners of different types operate with lumi- uous or non-luminous flame. Operation may be intermittent, continuous with high-low flame, or continuous with graduated flame. . Classification of Burners . Domestic oil burners may be classified by type of design or operation mto the following .groups: pressure atomizing or gun, rotary, and vapor- draft.or -pot. , T- he, s.e are further class.ified as mechanical draft, and natural, pressure Atomizing (Gun Type) Burner iDun type burners are usually designed to bum No. 1 or 2 grade fuel oil. "ey may jje divided into two classes: high-pressure and low-pressure 366 CHAPTER 15 1954 Guide atomization. The high-pressure atomizing type, illustrated in Fig. 12, is characterized by an air tube, usually horizontal, with oil supply pipe cen trally located in the tube and arranged so that a spray of atomized oil is introduced at about 100 psi, and mixed in the combustion chamber with the air stream emerging from the air tube. A variety of patented shapes is employed at the end of the air tube to influence the direction and speed of the air, and thus the effectiveness of the mixing process. A fan is used to supply the air for combustion. Ignition is established by a high-voltage electric spark that may be operative continuously while the burner is running, or just at. the beginning 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 constructed of re fractory material, or stainless steel, this being a part of the installation. Automatic Fuel Burning Equipment 367 or refractory material which is placed around the hearth. Dependent upon combustion adjustment, these burners may operate with either a semi- luminous or non-luminous flame. ., Both types of vertical rotary burners are further characterized by. their installation within the ash pit of the boiler or furnace. Various types of ignition are utilized, gas and electric, either spark or hot wire. The air for combustion is supplied partially by natural draft, and partially by fan effect of the central spinner element. 1 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 or one side. Heat for vaporization is supplied by the combustion process. Openings in the side 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 addi tional or secondary air is admitted to complete combustion. The openings Fig. 13. Center Flame Vertical Rotary Burner Fig. 14. Wall Flame Vertical Rotary Burner The low pressure atomizing type differs from the high pressure type mainly by having means for supplying a mixture of oil and primary air tOj the burner nozzle. The air pressure before mixing and the pressure of the,', oil-air mixture 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. 12. . Rotary Type Burner This class of burners may be divided into two groups: vertical an<F> horizontal. Most of the smaller rotary burners are of the vertical typejg and use a fuel oil of No. 1 or 2 grade. 1 -rf- The most distinguishing feature of vertical rotary burners is the principle*: of flame application. These burners are of two general types: the cent] flame and wall flame. In the former type (Fig. 13), the oil is atomizedhyjj being thrown from the rim of a revolving disc or cup, and the flame burns!; suspension with a characteristic yellow color. Combustion is support.;* by means of a bowl-shaped chamber or hearth. The wall flame burncy* (Fig. 14) differs in that combustion takes place in a ring of stainless Fig. 15. Vaporizing Forced-Draft Pot-Type Burner for admitting air are arranged to obtain gradual and intimate mixing of air and oil vapor for combustion, with a minimum amount of excess air and resulting high combustion efficiency. . Fuel is fed by gravity from a constant level control valve, and the flow 13 e,ther on (at rated capacity) or off (at pilot flow), according to the de mand of the thermostat. However, the high fire can be reduced and the, Pnot fire can be increased to give almost any desired control characteristic wuhin the range of the burner. The majority of vaporizing burners are f&anufactured in sizes up to one gallon per hour input. Most vaporizing offKwf8 are ''mited to use with No. 1 fuel oil having a maximum end point 625 F and a minimum A.P.I. gravity of 35 deg. , ^ barometric draft regulator is required to maintain the recommended fQru- A draft of not more than 0.06 in. of water column is recommended ^ost natural draft burners. When burners are equipped with mehjirri10^ forced draft, a slightly lower chimney draft can be used. A Figl6 lyPe *s illustrated in Fig. 15. A gravity type is shown in fU]^af>0r*z'rl8 burners are adaptable to water heaters, space heaters, and aces. Some types have also been applied successfully to conversion CHAPTER 15 '' t/ installations. The 'heat output , is in the range of requirements for the -i average or small home. , 7. * The modulating flame allows simple manual control by regulation ' of a metering valve, and simplifies the control equipment. Quiet combustion and the absence of moving parts contribute to quiet operation when the ' heating device is located in the living quarters. , ~ The ability to operate on natural draft and gravity feed of the fuel, makes possible the use of these burners where electric current is not available or is unreliable. However, most furnaces are thermostatically controlled, and many are provided with mechanical draft. ," Oil-Fired Boiler and Furnace Units . A number of types of specially designed oil-fired boiler-burner and furnace-burner units are available. Various locations of burners will lib . noted in such units; some having the combustion chamber and burner Automatic Fuel Burning Equipment 369 a. vauui using uumer prepares the oil for combustion by tra liquid fuel to the gaseous state by the application 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 combustion chamber with the liquid fuel particles, mixing, vaporization and burning occur all at once in the same space. This produces a luminous flame. A deficient amount of air is indicated 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 com bustion space. While extreme cases may be detected, it is not possible Fig. 16. Vaporizing Gravity Pot-Type Burner at the top, some at the bottom, and some at the center of the appliance. Typical combination units are shown in Figs. 17 and 18. The coordinated design of boiler (or furnace) and burner elements insures the optimum in operating characteristics, and the maintenance of balanced performance.. This type of equipment usually has more heating surface, and better flue- proportions and gas travel than conventional boilers or furnaces. Some1 of the better conversion installations, however, may equal the unit type in performance. Vm Operating Requirements for Oil Burners ^ The U. S. Department ofCommerce, in conjunction with the oil burner arid' heating appliance industries, has established commercial standards lor con-:. version burners and burner-appliance units which cover installation, con-;? struction and performance tests.4 ' Combustion Process . , fuel'' Efficient combustion must produce a clean flame and use a relatively;, small excess of air, i.e., between 25 and 50 percent. This can be don%` only by vaporizing the oil quickly and completely, and mixing it vigorous^-, with air in a combustion chamber hot enough to support the combustio^;- Fig. 17. Typical Boiler-Burner Unit ' to distinguish, by eye, the effect of the finer adjustment which competent installation requires. . , 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 combustion for a considerable..period following the initial adjustments of oil and air. Eventually, certain changes will occur, may be such that the amount of excess air will decrease below allow able limits.. A decrease in air supply while the oil delivery remains conmant, or an increase in oil delivery while the air. supply remains constant, ,, make the ore eff-ic-ient tmihneiiAxautudurjrueeso0tm1f eo01ni1lt,aatnnhdae aaiirr ttoooo rriicchh ffoorr more critical it cclleeaann ccoommbbuussttiioonn.. Tr. he will be. The oil and air .., rates must remain constant. . ^ . e following factors .may influence the oil delivery rate: (1) changes del' Vlscosity due to temperature change or variations in grade of oil p- lvered; (2) erosion of atomizing nozzle; (3) fluctuations in by-pass relief cl ssure i and (4) possible variations in methods of atomization. Any n8e due to partial stoppage of oil delivery will increase the proportion CHAPTER 15 1954 Guide 370 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 (*'.e., changes in chimney draft because of weather changes, seasonal changes, back-drafts, failure or inadequacy of automatic draft regulator, use of chimney for other; purposes, possible stoppage of the chimney, and changes in draft resistance; of boiler due to partial stoppage of the flues); and (2) changes in air inlet adjustments at the fan. Air leakage into the boiler or furnace setting should be reduced to a minimum. The amount of air leakage will be determined by the draft in the'combustion chamber. It is important that this draft should be reduced as low as is consistent with the proper disposal of the gases of combustion. When using mechanical draft burners with average' condi-!~ tions, the combustion chamber draft should not be allowed to -- 0.02-0.05 in. water. An automatic draft regulator is necessary in ordertt', maintain constant draft conditions which, in turn, improve efficiency?^, operation. The draft regulator should be adjusted in accordance witiiHJfeT manufacturer's instructions. `^4 Even though a fan is generally used to supply the air for combustion?., in most oil burners, the importance of a proper chimney should overlooked. The chimney should have sufficient height and size to insiu*; that the draft will be uniform within the limits given,if maximum efficfeogp throughout the heating season is to be maintained. Measurement of the Efficiency of Combustion . Since efficient combustion is based upon a clean flame and defi#.; proportions of oil and air employed, it is possible to determine the rj&jfe by analyzing the combustion gases. It is usually sufficient to anajxs;. only for carbon dioxide (C02) and to obtain the temperature of the gas. A showing of 10 to 12 percent indicates the best adjustment, | flame is clean. Most of the good installations show from 8 to 10 Automatic Fuel Burning Equipment 371 CO?. Taking into account the potential hazard of low excess air (high CO?), a setting to give 10 percent C02 constitutes a reasonable standard for most oil burners. Commercial Standard CS-75 requires that oil burners labeled as complying with the standard shall obtain smoke-free combustion at 10 percent C02. 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 manufacturer's instructions. It is important that the chamber be as nearly air tight 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 com bustion chamber surfaces to vaporize the oil and' support combustion. Unsatisfactory combustion may be due to inadequate atomization and mixing. A combustion chamber 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 enough below the nozzle to avoid flame contact, the sides tapering from the air tube at the same angle 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 vaporization, rapid combustion and better mixing by elimi nating 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 design becomes a less critical matter. Where secondaiy air is used, combustion chamber design is quite important. When installing some of the vertical rotary burners, the manufacturer's instructions must be followed carefully when installing the hearth, as in this class successful performance depends upon this factor. Boiler Settings . As the volume of space available for combustion is a determining factor m oil comsumption, it is general practice to remove grates and extend the combustion chamber downward to include or even exceed the ash pit 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 to 2.5 lb of oil per hour can properly be burned. This corresponds to an average liberation of about 38,000 Btu per cubic foot per hour. At times uch 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 U8?d 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 gapted to flat flames, or to conical flames that can be spread over the tnS" * combustion chamber. The proper bricking of a large or even edium sized boiler for oil firing is important, and frequently it is advisable consult an authority on this subject. The essential in combustion chamber design is to provide against flame impingement upon either me- .. tallic or firebrick surfaces. Manufacturers of oil .burners usually have available detailed plans for adapting their burners to various types of boilers, and such information should be utilized. Controls for oil burner operation, including devices for the safety and protection of a boiler or furnace, are fully described in Chapter 39. - COMMERCIAL AND INDUSTRIAL OIL BURNERS Oil burning equipment for commercial and industrial applications is usually designed for burning the lower cost 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 characteristics of the industrial fuel oil to be used. These characteristics should, therefore, be given careful con sideration when setting up the specifications of the fuel oil for which the system is to be designed. Classification of Burners These burners are usually classified according to the method used for' atomizing the oil as (1) horizontal rotary cup atomizing, (2) mechanical pressure atomizing, (3) steam atomizing, 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 oil is spun from the rim of the- eup, it enters a cone of high velocity primary air and very effective atomizaj, tion is obtained. In most applications secondary air for combustion ^ supplied by natural draft through checkered openings in the floor of the combustion chamber. In some applications, however, the secondary is admitted through openings surrounding the burner nozzle and may 'be supplied by forced draft. ''!i The rotary cup burner has been the most popular type in the capacity range from approximately 25 to 500 boiler horsepower. , Its principal vantages are that it is a self-contained integral unit; it is readily adaptable, to manual, semi-automatic, or fully-automatic control; and the firing, raw may be easily modulated through a wide range while maintaining high, combustion efficiencies. These burners are frequently used for firing pack;' age-d S. team generator units. . ' . . . f`f4- Mechanical Pressure Atomizing Burner , a-ys> In this burner oil is'atomized by- passing it through a specially desjjpg*nozzle under pressures of-approximately 100 to 250 psig. The air fpr-doip; bustion may be supplied -by either natural or forced draft, and is ugu?? admitted through an air register-surrounding the burner nozzle or throng?' checkered openings in the fioor of the combustion chamber. This burn?! is popular for marine service and for large capacity multiple,installahn^ It is not readily adapted to'fully automatic operation. ! ij'ii Automatic Fuel Burning Equipment . . . 373 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 approximately 50 to 150 psig is admitted to the nozzle by various methods to assist in the atomization. Combustion air is usually 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 operation or wide variations in firing rate. Air Atomizing Burner The air atomizing burner is similar to the steam atomizing 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. ' Heating the Oil Commercial Standard No. .4 fuel oil is intended for use in burners that are not equipped with preheating facilities. Nos. 5 arid 6 oils usually require preheating equipment to reduce their viscosity sufficiently for satis factory pumping and atomization. Some oils in the lower viscosity range of No. 5 specification may at times be handled without preheating, but definite viscosity limitations should be specified if this is attempted. In northern climates, the pour point of oil may affect the preheating require ments and should be included in the oil specifications/ " The common heat sources employed in the heating of fuel oil are steam, hot water and electricity. Shell and tube type heaters connected to the oil fired boiler are normally used for steam or. hot water heating. It is extremely important in many plants to provide oil heating equipment that will readily permit starting the burner after a prolonged shutdown during cold weather. While the initial cost of this heating system may be higher, it is necessary where a plant shutdown may cause the oil in the tank and ml lines to congeal to a point where circulation cannot be re-established unless the oil preheating system is designed for this type of service. OIL STORAGE TANKS AND PIPING Storage tanks, also the piping and pumping facilities for delivering the on from the tank to the burner, are very important considerations in the nesijpi of an industrial oil burning system. The construction and location i the tank and oil piping are usually subject to local regulations which stiould always be consulted, and to the standards of the National Board of tre Underwriters, such as NFBU Pamphlet No. 31. The size of the storage tank is usually based on the rate at which oil is M !?e consumed, the space available, method of oil delivery (truck or tank rJ and the ease with which deliveries can be made under all weather is d ns` ^ minimum capacity of at least the maximum weekly usage J'fmble. If deliveries are to be made by tank car, the capacity should 1 he less than 15,000 gal. . The 275 gal oil storage tank is commonly used for domestic installations. 374 CHAPTER 15 1954 Guide In most localities it may be installed in basements without being enclosed. Where a greater storage capacity is necessary, local regulations usually permit inside installation of two tanks of 275 gal each in accordance with NBFU Standards Pamphlet No. 31. ; 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 atmos pheric 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 Automatic Fuel Burning Equipment 375 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 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 common type is quite, similar to Fig. 18 except that gas burners, pilots, controls, and gas pressure regu lator 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 Ideation of the furnace less critical than in gravity systems. Designs of forced air furnaces vary from the conven tional types that deliver heated air to overhead ductwork to the downblow types wherein the heated air is delivered at the bottom of the furnace, this in a number of types of domestic gas heating appliances and systems?. These may be classified 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 anil;' forced warm air furnaces or steam and hot water boilers are used, and for other applications where warrri air floor furnaces and room heaters arc- installed in the space being heated. Central Heating Systems .`fii Boilers and furnaces specially designed for gas-firing incorporate design^ features for obtaining maximum efficiency and performance. Small passes to secure good heat transfer, the use of materials resistant to tjpg corrosive effects of products of combustion, and draft hoods are notablej features. Control equipment includes gas pressure regulators, autobiabcj pilots, and limit controls designed to protect the appliance and to safety of operation. A boiler designed for gas-burning is illustrate??! in Fig. 19. fig Gas designed boilers for hot water or steam heating are available fig. 20. Typical Single Port Gas Conversion Burner 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 compactness. The A .G.A. listed output at the boiler nozzle or at the bonnet for forced air and gravity furnaces is 80 and 75 percent, respectively, of the approved input to the burners. Conversion Burners Conversion burners are usually complete burner and control units de signed for installation in existing boilers and furnaces. A typical gas con version burner is shown in Fig. 20. Atmospheric conversion burners may have drilled port, slotted port, or single port burner heads. Single port ypes have become increasingly popular in the last few years due to their simplicity of construction and ease of installation. In rectangular or round, -foled and slotted port burners baffles of clay or metal are usually used to feet the products of combustion toward the side walls of the combustion camber. In single port burners the flame usually impinges against a pfizontal cast-iron, stainless steel, or ceramic distributor plate which rects the products of combustion toward the side walls. For certain Ppucations, particularly wet base boilers, a horizontal single port burner 376 CHAPTER 15 . 1954 Guide is utilized. This design produces a horizontal flame which strikes a curved baffle.that spreads the flame in a 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 obtain the desired output. ' . Conversion burners for domestic application are available in sizes ranging from 50,000 to 400,000 Btu per hr capacity. It should be noted that the American Standard Approval Requirements are limited at present to con version burners of capacities up to 400,000 Btu per input hr. 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 assembly of multiple burner heads filling the entire firebox. For conversion burner installation in boilers requiring more than 400,000 Btu per hr input, reference should be made to the American Standard Requirements for Installation of Gas Equipment in Large Boilers, ASAZ21.33-1950. Domestic sizes of conversion burners should conform to American Stand ard Listing Requirements of Conversion Burners, ASA Z21.17-1948. As the successful and safe performance of a gas conversion burner depends on numerous factors other than those incorporated in such equipment, instal lations of this kind must be made in strict accordance with American Standard Requirements for Installation of Domestic Gas Conversion Burn ers, ASA Z21.8-1948. Also, draft hoods conforming to American Standard Listing Requirements for Draft Hoods, ASA Z21.12-1937, R 1950, should be installed (in place of the dampers used with a solid fuel) on all boilers: and furnaces intended to operate without chimney draft. The A.G.A.- lists the output efficiency of conversion burners at 72 percent. This valuer is based on average installations and average heating equipment perform-- ance. .' One form of central heating system i*s t1h1 e warm----------' air floorffmu*rnnoa/>cAe.56 TT]}h6e. use of these furnaces is adaptable to mild climates, or for auxiliary heating or heating of single rooms in colder climates. They are used for heating , first floors, or where heat is required in only one or two rooms. A number may be used to provide heat for the entire building where all rooms are on, the ground floor, thus giving the heating system flexibility. . ->/ In floor-fumace 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-typL installed in the floor, or of the dual-type installed in a partition, and heating! two rooms. The A.G.A. rating of floor furnaces is based on an efficiency of 70 percent. 'j&y A recent type of central heating, used in mild climates, is the reccss&l- heater which is either a gravity or forced-air furnace designed for installif;7 tion in the interior partition of a building, and having stub ducts conduct;-.' ing air to two. or more rooms. This type of heater is usually installed :)P new homes, and is plastered into the wall, becoming a permanent part,,,||. the building. Vff Space Heaters Space heaters are defined as heating units that take the air for cgS&i bustion from the space being heated. They may be broadly classiwh-* as room heaters and unit heaters. TAf! Automatic Fuel Burning Equipment 377 Room healers are used for heating single rooms or connecting rooms with good circulation between them and, except for wall-type heaters, they are semi-portable. Unvented-type room heaters should not be used unless space is properly ventilated to prevent excess moisture and to provide sufficient combustion air to prevent formation of carbon monoxide. All types of room heaters are capable of automatic control, although they are generally controlled manually. When equipped for automatic control, they must have an automatic pilot as part of the control equipment. Room heaters may be classified as follows: ' Circulators, vented and unvented, are small warm air furnaces 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 healers, usually unvented, although some vented types are avail able, have a refractory directly above the burners which is heated to in candescence, and gives off at least 30 percent of its heat in the form of radiant energy. ' Gas-fired steam and hoi water radiators, vented and unvented, are similar in appearance to an ordinary steam or hot water radiator, but are self- contained, and the gas input is controlled by steam pressure or water tem perature within the radiator. Warm air radiators are vented or unvented circulators whose heating elements are constructed in the form of a steam radiator. Walt 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. The A.G.A. rating of room-type heaters is based on an efficiency of 70 percent. , Unit heaters are used extensively for beating 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.G.A. approval. When connected to ducts they must have sufficient blower capacity to deliver an adequate air quan- hty against the duct resistance. Duct furnaces are usually of the unit heater type without the fan, and are used for heating air in existing duct systems where blowers are pro dded for moving the air through the system. Duct furnaces are tested for Peration at much higher static pressures than are obtained in unit heaters. Combustion Process and Adjustments - Most domestic gas burners are of the atmospheric injection (Bunsen) ,?Pe M which primary air is introduced and mixed with the gas in the uroat of the mixing tube. For normal operation of most atmospheric ype burners, 40 to 60 percent of the theoretical air as primary air will |iv best operation. Slotted port and ribbon burners may require from. to 80 percent primary air for proper operation. The amount of excess of, (ecflfired in practice depends upon several factors, notably: uniformity hefti ^'^'bution and mixing, direction of gas travel from burner, and the Util - anc* temperature of combustion chamber. With power type burners the ^ Iritr driven blowers to provide both primary and secondary air, ~ excess air can be closely controlled while securing proper combustion. 378 CHAPTER 15 1954 Guide 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 ad justment should be followed. Gas designed equipment does not usually incorporate any means for varying the secondary air supply (and hence the COO- The amount of effective opening and baffling is determined by A.G.A. tests and cannot be varied. Gas conversion burners, however, do incorporate means for con trolling 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 installation manual required to be - supplied with each burner should be followed. It is possible through the use of suitable indicators to determine whether carbon monoxide is present in flue gases. Carbon monoxide should not exceed 0.04 percent when operating at the maximum gas input to the burners. During recent years, the use of fuel gas (natural, manufactured, and liquified petroleum) has become increasingly popular for heating tourist cabins and motels. Due largely to the intermittent use of such equipment and the fact that so many of the users are entirely unfamiliar with the fundamentals governing its operation, many special and unusual problems arise. The importance of safe-guarding 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 w which they must be equipped with reliable safety devices, for example, connection to an effective flue is mandatory. Furthermore, all such heatingequipment must incorporate an automatic ignition pilot which will shut off gas supply to the main burner or burners in the event of pilot outageIf liquified petroleum gas is used, the automatic pilot must cut off all 0 supply to the appliance, including the pilot burner, in case the pilot flame- becomes extinguished. r_ Ratings for Gas Appliances ' Input rating for a gas appliance is established by demonstrating that; the appliance can meet the Approval Requirements of the ASA. Tig- tests are conducted at the A.G.A. Laboratories. Output rating is deter-, mined from the approved input and an average efficiency stated in Approval Requirements, and is the heat available at the outlet. sT 4y Sizing Gas-Fired Heating Plants G Although gas-burning equipment usually is completely automat}'?!, maintaining the temperature of rooms at a predetermined figure, theig atirveeslyomtheemsatanrutainllgy lcooandtroalnleddloinsssetasllaintiopnips.ingI,naomrdaenrutaollyo-vceornctoromlleed SK- ; Automatic Fuel Burning Equipment 379 boiler should have an output as much as 100 per cent greater than the equivalent standard radiation which it is expected to serve. ' Boilers under thermostatic control, however, are not subject to such severe pick-up loads and consequently, it is possible to use a lower selec tion factor. For a gas-fired boiler or furnace under thermostatic control, a factor of 20 to 25 percent is usually sufficient for pick-up allowance. In those installations, in mild climates where 100 per cent outside air is used, furnaces should be of larger size in order to provide adequate capacity and quick pick-up under intermittent heating conditions. The factor to be allowed for loss of heat from piping will vary somewhat, the. proportionate amount of piping installed being greater for small installations than for large ones. For selection factors to be added to installed radiation under thermostatic control, see Chapter 16. Table 1. Capacity of Gas Piping Length of Pipe in Feet Nominal Diameter of Pipe in Inches Capacity Cn Ft Per Hr noth a 0.6 Sp Gr Gas and Pressure Drop of OJ' Water Column 15 30 45 60 75 90 105 120 150 180 172 120 99 86 77 70 ' 65 345 241 199 173 155 141 131 120 109 100 750 535 435 380 345 310 285 270 242 225 850 700 610 545 490 450 420 380 350 920 860 780 720 Appliances used for heating with gas should bear the approval seal of the A.G.A. Laboratories on the manufacturer's nameplate, together with the official input and output ratings. It is not permissible to operate a gas heating unit above its stated rating. It may be necessary to operate below this rating at elevations above 2000 ft, unless the appliance has been tested and approved for operation at altitudes up to 5200 ft, in which case such approval will be shown on the manufacturer's nameplate. Installa tions should be made in accordance with recommendations shown in the publications of the American Gas Association. Controls Temperature controls for gas burners are described in Chapter 39. Some central heating plants are equipped with push-button or other manual control. The main gas valve may be of either the snap action or throttling type. Automatic electric ignition is available. 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 udue loss of pressure between the point of supply (the meter) and the uroer. The size of gas pipe required depends upon the following: b 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. ' ' v _ To obtain the cubic feet per hour of gas required by the burner, divide V? the Btu input at which the burner will be adjusted,' by the average Btu heating value per cubic foot of the gas. Iff) Capacities of different sizes and lengths of pipe, in cubic feet per hour, |.f with a pressure drop of 0.3 in. of water column for a gas of 0.60 sp gr,79 are shown in Table 1. In adopting a 0.3 in. pressure drop, due allowance^? for an ordinary number of fittings was made. Jsr,- To convert the figures given in Table 1 to capacities for another gas of|*j different specific gravity, multiply the tabular values by the multipliers^ shown in Table 2. .- . ' VV Table 2. Multipliers for Various Specific Gravities For Use With Table 1 _____________ Jp Specific Gravity .35 .40 .45 .50 .55 .60 .65 .70 .75 .80 .85 .90 Multiplier 1.31 1.23 1.16 1.10 1.04 1.00 .962 .926 .895 .867 .841 .817 Specific Gravity 1.00 1.10 1.20 1.30 1.40 1.50 1.60 1.70 1.80 1.90 2.00 2.10 Multiplier .775 .740 .707 .680 .655 .633 .612 .594 .577 .565 .547 .535 COMMERCIAL AND INDUSTRIAL GAS EQUIPMENT 1 No attempt can be made, due to space limitation, to describe or classigvfthe varied types of equipment used for commercial and industrial appUcjSSr tions. Much of the equipment utilized is custom built to suit a partied^ process. Certain standard parts such as venturi and burner head $0-$ ring burners, proportional mixers, or compressors, are purchased forjj^S sveidmebplyarinticeuxlaisrtiantgmoesqpuhipemreesnot,r ufosur aalnlynebaylinthge, sinosatkainllegr.pi,tsF,umrneatcaelsmelting!: etc. are usually engineered by industrial gas equipment manufacturere^g: Burners utilized in industrial equipment often operate at gas pressures;> higher than encountered in domestic usage. High pressure gas prowdj|yi flexibility of control required in the production of constant temperature^.; In addition, air-gas ratios can be closely maintained under throttling cdncfe tions, 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-p'l^v high pressure, proportional mixing, pre-mix, two-pipe high pressure, atmospheric. '. The single-pipe high pressure burner system utilizes gas delivered orifice of a venturi at pressures from 10 to 50 psig. A constant press'^/ compressor, sometimes remotely placed, is occasionally used to increasfjyg Automatic Fuel Burning Equipment 381 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 venturi, is used and high pressure air is delivered through an orifice. 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 side 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 GROSS OUTPUT-THOUSAND BT.UPER HOUR i~ i 02 l O Sr-T--r-1--i--i l I I ~ 1~" I l *H l | \ l | l I T T* 4 6 8 K> 12 W B 18 20 CROSS OUTPUT - HUNDRED FEET STEAM RADIATION 10 20 25 i S"tO.r-i--r-i--r--i----i--i--r--r--i--i--i--i--i--i--m--I--l~l "T"1 r I GROSS OUTPUT-HONORED FEET WATER RADIATION Fio. 21. Coal Fuel Burning Rate Chart where it is discharged through orifices and burned'. The pre-mix compres sor can be remotely 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 to 12 in. water. A portion of the LIr o(' Primary air required for combustion is entrained from the atmosphere cy the stream of gas issuing from an orifice, and the air-gas mixture is eiivered through a venturi mixing tube to the burner head and parts. * Pout 40 to 60 percent of the air required for combustion is.in the form of P mary air and the remainder, known as secondary air, is supplied from ne air surrounding the flame. - ItEac|> system embodies characteristics essential for certain applications, y's,s^rongly recommended that proper and qualified engineering authori- trioi 6 coasulted prior to the purchase, installation, or operation of indusal gas equipment. * This chart is based upon No. 2 oil having a heat content of 143,400 fitu per gallon. II other grades ol oil are used multiply the value obtained from this chart by the following factors: No. 1 oil (139,000 Btu per gallon) 1.032; No. 4 oil (144,500 Btu per gallon) 0.992; No. 5 oil (146,000 Btu per gallon) 0.982; and No. 6 oil (150,000 Btu per gallon) 0.956. ' . - Automatic Fuel Burning Equipment 383: FUEL BURNING RATES The burning rate for automatic fuel burning devices is determined by. the gross heat output required of the boiler, or furnace, to carry the net heating load, plus allowances for system losses and pick-up.. General values for these allowances have been given in preceding text. Detailed information for piping and pick-up allowances for steam and hot water systems, is given in Chapter 16, and for warm air systems, in Chapters 19 and 20. ' When the gross output, operating efficiency, and heat value of the fuel are known, the required rate of burning can be determined by means of Figs. 21, 22 and 23 for the several fuels. ' As the rate of fuel burning is directly proportional 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 case of coal stokers, which are usually capable of variable rates of firing, it is desirable to operate at as low a rate as weather conditions will permit, but the maxi mum firing rate of the stoker should be sufficient to carry the gross load. This rate may be determined by the same method as used for oil or gas. REFERENCES `Domestic Burners for Pennsylvania Anthracite (Underfeed Type), ((/. S. De partment of Commerce, National Bureau of Standards, Gommerciaf Standard No. CS48-40). ' Stoker Manufacturers Association Manual: Industry Standards, Recommended Practices, Technical Information. Published by Stoker Manufacturers Association, 307 N. Michigan Ave., Chicago 1, 111. * Code for Determination of Rated Capacities of Anthracite Underfeed Stokers, adopted June 1, 1944, and a Code for Determination of Rated Capacities of Bitumi nous Underfeed Stokers, adopted May 3, 1944. See Stoker Manufacturers Associa tion Manual. (11 ^ u,0Ina*'c Mechanical Draft Oil Burners Designed for Domestic Installations N ncPeporfment f Commerce, National Bureau of Standards, Commercial Standard OS75-42). Flue Connected Oil Burning Space Heaters Equipped with Vaporizjng Pot Type Burners (U. S. Department of Commerce, National Bureau of Standards, t'Ommercial Standard No. CS1Q1-43). Warm-Air Furnaces Equipped with Vaporizn Pot-Type Oil Burners (V. S. Department of Commerce, National Bureau of Stand_^"' Commercial Standard No. CS104-46). Oil-Burning Floor Furnaces Equipped Hb Vaporizing Pot-Type Burners (!/- S. Department of Commerce, National Bureau 1 standards. Commercial Standard No. CS113-44). o , pas Floor Furnaces, Gravity Circulating Type (U. S. Department of Commerce, tional Bureau of Standards, Commercial Standard No. CS99-42). BIBLIOGRAPHY Performance Expectancy of Domestic Underfeed Stokers for Anthracite, by Allen Johnson (Transactions, A.I.M.B., Coal Division, Vol. 119, 1936). The Relation of the Size of Bituminous Coals to Their Performance on Small Underfeed Stokers--Burning Tests on Four Typical Coals, by R. A. Sherman, it. K. *Sa>ser and H. R Limbacher, Technical Report No. 1, Bituminous Coal Research, nc- (July, 1937) Part II. il Fuels and Burners, by James A. Moyer (McGraw-Hill). Handbook of Oil Burning, by Harry F. Tapp. Handbook of Oil Burning, by F. H. Faust, Editor-m-Chief, and/G. T. Kaufman, Editor (Oil Heat Institute of America, New York). . . Domestic Oil Burners, Installation.and Servicing, by C. H. Burkhardt- (McGraw- HilAl BSotuodkyCoof.,thNeeOwilYBourkrn)e. r as Applied t-o Domestic Heating, by Arthur H. Senner ?.<S (Technical Bulletin 109, U. S. Department of Agriculture). 4. Progress in Domestic Oil Heating, by Rene J. Bender (Mechanical Engineering, ibi October, 1942). ,h.s. OilAB.Sur.Hne.Vrs.Ea.nRd eLsoewarPcrehsRsuerpeoHret aNtion.g9B07o--ileSrtsu,dbyyoLf .PEe.rfoSremealenyceanCdhEar.aJc.teTriasvtiacnslaofr (A.S.H.V.E. Transactions, Vol. 37, 1931, p. 517). fA.S.H.V.E. Reseabch Report No. 925--A Study of Intermittent Operation of Oil % Burners, by L. E. Seeley and J. H. Powers (A.S.H.V.E. Transactions, Vol. 38, 1932, p. 317). . 7ig Air Supply and Its Effect on Performance of Oil Burners and Heating Boilers, by ^v L. E. Seeley, J. H. Powers and E. J. Tavanlar (A.S.H.V.E. Transactions, Vol. 39, 1933, p. 75). .7 . H Study of Fuel Burning Rates and Power Requirements of Oil Burners in Relation1 to Excess Air, by L. E. Seeley and E. J. Tavanlar (A.S.H7V.E. Transactions, V61ifi| '{ 40, 1934, p. 319). ` 'liv Oil Burning in Residences, by D. W. Nelson (A.S.H.V.E. Transactions, VoI.-4I?>rt 1935, p. 355). . A Study of Oil-Fired Heating Boilers, by R. C. Cross and W. R. Lyman (Heating?^ and Ventilating, October, 1931). Gaseous Fuels (American Gas Association). ' 4 ' 'y'y i Comfort Heating (American Gas Association). Americ an Stand- a rd Approval Requirem. ents for Central House Heat.ing Gas Ap-m pliances, ASA Z21.13- (American Standards Association). VOol. I1.. Soteam-anud Huoout Wnaawteir Boilers, Z__2_1_._1_3.1-1951. Vol. II. Gravity and Forced Air Central Furnaces, Z21.13.2-1951, with addenda..'^ Z21.13.2a-1952. Vol. III. Gravity and Fan Type Floor Furnaces, Z21.13.3-1951. ;i Vol. IV. Gravity and Fan Type Vented Recessed Heaters, Z21.13.4-1951. American Standard Requirements for Installation of Domestic Gas Conversion;; Burners, AS.4 Z21.8-1918 (American Standards Association). '7 ^ American Standard Requirements for Installation of Gas Equipment in Largej>| Boilers, Z21.33-1950 {American Gas Association). }< American Standard for Installation of Gas Piping and Gas Appliances in Buua tiiKJ&i' ings, Z21.30-1950 (American Gas Association). ^, 1951 A.G.A. Industrial Gas School Lectures (American Gas Association). Radiant Gas Burners, by J. D. Keller, A.G.A. Sales Conference, 1949 (Amerioin.H, Gas Association). Industrial Furnaces, Vol. 1 & 2, by W. Trinks. (John Wiley &.Sons, 1944). ' ; A Method for Determining Fuel Burning Rates in Heating Boilers Fired by Autog';;J matic Devices, by R. C. Cross (Heating and Ventilating, January, 1932). . Heat Losses and Efficiencies of Fuels in Residential Heating, by R. A. Sherman ; and R. C. Cross (A.S.H.V.E. Transactions, Vol. 43, 1937, p. 185). , . - ' - ' . .. - ffiy. * HEATING BOILERS, FURNACES, SPACE HEATERS BOILERS: Construction, Types, Design Considerations, Testing and Rating Codes, Efficiency, Rating, .Selection, Space Limitations, Connections and Fittings, Erection, Operation and Maintenance. FURNACES: Types, Materials and Construction, Ratings, Testing and Rating Codes, Efficiency, Design Considerations, Humidification Equipment. SPACE HEATERS: Types: Solid Fuel, Oil, Gas; Materials and Construction, Testing and Rating, Design Considerations, Installation IN presenting the subject of Boilers, Furnaces and Space Heaters this chapter is divided into three part's; 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 are built of steel or cast-iron in a wide variety of types and sizes, many of which are illus trated in the Catalog Data Section. CONSTRUCTION The nationally recognized code governing the construction of low-pres sure steel and cast-iron heating boilers is the ASMS 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 to 15 psi for steam and 30 psi for hot water heating boilers. Hot water boilers may be used for higher working pressures, for heating pur poses or for hot water supply, when designed and tested 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 cw non-ferrous boilers are made. fi According to tbe fuels for which the boilers are designed. These are coal, handfr 1 ?,r stker-fired; oil; gas; or wood. Some boilers are designed specifically for one uel, but many boilers are designed for more than one fuel. si t According to the specific purpose or application for which the boiler is used, ch as space heating or domestic not water supply. g According to the design or construction of the boiler such as sectional, round, tube, water-tube, magazine feed, Scotch, etc. Cast-Iron Boilers Oast-iron boilers are generally classified as: comor rectangular boilers with vertical sections and rectangular grates, 2 ' ^ known as sectional boilers. * Round boilers with horizontal pancake sections and circular grates. 385 386 CHAPTER 16 1954 Guide Cast-iron boilers are usually shipped in sections, and assembled 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 between adjacent sections at both the water line and bottom of the boiler, which is necessary to enable the use'of an indirect 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 sides and bottom are sur rounded by extensions of the water legs of the boiler sections, and thus no 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 capacities 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 E.D.R. Steel Boilers Steel boilers may be of the fire-tube type, in which the gases of combus tion 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 arranged: for refractory lined brick or refractory lined jacketed furnaces. Thoss 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 35,000 sq ft of steam radiation. Boilers for Special Applications One of these is known as the magazine feed boiler developed for the burning of small sizes of anthracite and coke, and has a large fuel carrying capacity, which results in longer firing periods than 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 insure adequate draft. . / Boilers for hot water supply are classified as direct, if the water heate<! passes through the boiler, and as indirect, if the water heated does not coin in contact with the water or steam in the boiler. Direct healers are built to operate at the pressures found in city suRPjf mains, and are tested at pressures from 200 to 300 lb per square tap'; The life of direct heaters depends almost entirely on the scale-fonri| properties of the water supplied and the temperatures maintained. , F low water temperatures are maintained, the life of the heater will be longer due to decreased scale formation and minimized corrosion. Dire;;, water heaters in some cases are designed to burn refuse and garbage-ii4 Indirect heaters generally consist of steam boilers in connection - heat exchangers of the coil or tube types which transmit the heat frfflfliTM <58/ steam to the water. This type of installation has the following advantages: 1. The boiler operates at low pressure. 2. The 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 heat exchanger. A. Discoloration of water may be prevented if the water supply comes in'contact with only non-ferrous metal. Where a steam or a forced circulation hot water heating system is in stalled, the domestic hot water may be heated by an indirect heater at tached to the boiler. For most satisfactory 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 pos sible with respect to the boiler. BOILER DESIGN CONSIDERATIONS Furnace Design Good efficiency and proper boiler performance are dependent on correct furnace design. There-must be sufficient volume for burning the particular fuel which is used, and means to obtain a thorough mixing of air and gases at a high temperature 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 14 and 15.) 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 heating surface, its distribution, and the temperatures on either side thereof, in fluence 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 small as to cause excessive resistance to the of gases, where natural draft is employed. Inserting baffles so that the heating surface is arranged in series with respect to the gas flow, in creases boiler efficiency and reduces stack temperature, but increases the re/t loss through the boiler. ' Seat Transfer Rate . Practical average overall heat transfer rates, expressed in Btu absorbed Q square foot of surface per hour, will average about 3300 for hand-fired ^ .ers> and 4000 for mechanically-fired boilers when operating at design as r{ e "!*e.n mechanically-fired boilers are operating at maximum load, trill eilnec^ 'n this chapter under heading Selection of Boilers, these values diti fUn ^ween 5000 and 6000. Boilers operating under favorable con- ons at these heat transfer rates, will give exit gas temperatures that 388 CHAPTER 16 1954 Guide are considered consistent with good practice, although there are boilers: which have high efficiencies and also operate at higher 'transmission rates. TESTING AND RATING CODES The Society has adopted four solid fuel testing codes, a solid fuel rating code, and an oil fuel testing code. 1 ASHVE Standard and Short Form Heat Balance Codes for Testing Low-Pressure Steam Heating Solid Fuel Boilers--Codes 1 and 2--(Re vision of June, 1929),1 provide a method for conducting and reporting tests to determine heat efficiency and performance characteristics. ASHVE Performance Test Code for Steam Heating Solid Fuel Boilers --Code No. 3--(Edition of 1929)1 is intended for use with ASHVE Code" (withdrawn in 1953) for Rating Steam Heating Solid Fuel Hand-Fire^ Boilers.2 The object of this test code is to specify the tests to be conducted^! and to provide a method for conducting and reporting tests to determine the efficiencies and performance of the boiler. ,, The ASHVE Standard Code for Testing Steam Heating Boilers Burning Oil Fuel,2 (Adopted June, 1932), provides a standard method for con ducting and reporting tests to'determine the heating efficiency and per formance characteristics when oil fuel is used with steam heating boilers'!' The ASHVE Standard Code for Testing Stoker-Fired Steam Heating. Boilers,4 (Adopted June, 1938), provides a test method for determining' the efficiency and performance characteristics of any stoker and boiler combination burning any type of solid fuel, such as anthracite or Bi tuminous coal. -ksH The Steel Boiler Institute, Inc. has adopted a Rating Code for Gommercial Steel Boilers and Residential Steel Boilers, and for Testing OilFired Residential Steel Boilers (Fifth Edition as Revised Jan. 1, 1948)i The commercial boilers (defined as those having 129 to 2500 sq ft of heating surface) are rated in square feet (steam) on the basis of heating surface with limitations set for grate area, furnace volume, and furnace height- Table 1. SBI Net Rating Data, fob Residential Steel Boilers--Oil FibhT . -Sq Ft Steam 275 320 400 550 700 9Cg) 1100 1300 1500 1300 2200 2600 3000 SB/Net Rating Sq Ft Water 440 510 640 880 1120 1440 1760 2080 2400 2880 3520 4160 4800 Btu 66000 77000 96000 132000 168000 216000 264000 312000 360000 432000 528000 624000 720000 Minimum : Furnace Volume Cu Ft 2.5 2.9 3.6 5.0 6.4 8.2 10.0 11.8 13.6 16.4 2o;o 23.6 27.3 Heating' Surface Sq Ftjp. - ) 'i 16 19 24 32; 41-,rtB 65 f? 88.1" ft 153 . 177.:; " B Stoker-fired and Gas-fired SBI Net Rating not greater than Oil-fired. Hand-fired, SBI (Steam) not greater than 14 times the square feet of heating surface. _ - for Commercial Steel B oilers Heating Boilers, Furnaces, Space Heaters 389 390 CHAPTER 16 1954 Guide The residential boilers (defined as those having not more than 177 sq ft of heating surface) are rated from tests of oil-fired boilers, with limitations in relation to heating surface and testing conditions. Stoker-fired and gas-fired residential boilers are rated (SBI Net Rating) not in excess of the oil-fired rating. Hand-fired residential boilers are rated (SBI Net Rating) not greater than 14 times the heating surface. Tables 1 and 2 show the SBI ratings of residential and commercial steel boTilehres,InresstpituectetivoeflyB.oiler and Radiator Manufacturers has adopted a Code1 for rating cast-iron heating boilers, based upon performance obtained under controlled test conditions. This Code applies to all sectional cast- iron heating boiler except those of magazine-feed type. ' The Gross I ~ B -- R Output is obtained by test, and is subject to cer-' tain limiting factors. For hand-fired boilers, the number of boilers of a series to be tested, the minimum overall efficiency, the minimum time limit (the time an Available Fuel Charge will last when burned at a rate; which will produce the Gross I -- B=R Output), the chimney area and' 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 coal. J; For automatically-fired boilers, the number of boilers of a series to he; tested, the flue gas temperature and analysis, the minimum overall ciency, the draft loss through the boiler, and the heat release in the com:}, bustion chamber are subjected to limitation by the Code.6 Automatical!}';'? fired boiler ratings are established by oil-fired tests using gun type ioil. burners and commercial grade No. 2 fuel oil. Stoker-firea and gasdircd''. ratings (where no A.G.A. Rating is published) are based on the Cross? l --TBhe-- RNeOt u1tp~uBt o=bFtat inReadtibnyg oisil-fdireetdertmesintse.d from the Gross I -- B=7L Output by applying specified Piping and Pickup Factors which range from, 2.36 to 1.40 lor hand-fired boilers, and from 1.56 to l .288 for automaticallKj fired steam boilers, and from 1.333 to 1.288 for automatically-fired water boilers. In all cases, the factor decreases as the boiler size toy creases. Table 3 is abstracted from the 1951 7= B= ft Boiler Tables in the Code and illustrates the relationship between Net I=F4b: Rating and Gross l -- B -- R Output. | The American Gas Association rates gas designed boilers at 80 percen) of the A.G.A. Input Rating. These ratings are determined byi lormance tests described in the A.G.A. Approval Requirements for Centjg* Heating Appliances. 1' The Heating, Piping and Air Conditioning Contractors National h-C sociation has adopted a method, based on their physical characteristics-w rating boilers that are not rated in accordance with the SBI or / = Codes. Ratings are expressed on a Net Load basis in square feet of sfeiff radiation. :V BOILER EFFICIENCY '" The term efficiency, as used for guarantee of boiler performance, is usU ally construed as follows: ' 1. Solid Fuels. The efficiency of the boiler alone is the ratio of the heat by the water and steam in the boiler per pound of combustible burned on the to the calorific value of 1 lb of combustible as fired. The combined effiotc boiler, furnace and grate is the ratio of the heat absorbed by the water and s' the boiler per pound of fuel as fired, to the calorific value of 1 lb of fuel as fir Heating Boilers, Furnaces, Space Heaters 391 l^J ' d Jg.' * S; Sillls S22s SBI : : : Safi ' a; Sl5 " oooooo eooooe ooo - " - ;;:... .* ; r ; ; ; .... . . ... , ;;*' , - a' |H"S s SSSRS 33355s' 8SSSS8- S888S3 S38888 21* aoS2 cS8aa 3 ?!!!!!!!!!!! f" . 'S 2 !!?!!! !!!!! mm mmm , mill iiim l!!!H min min hi L 3 a &. - 4 OJ J,, CO 2 I n D 2 *9* snm mm mm mm m 1 I s . - ***" ** Mill! IISIII SifiiS Sil i 01. t5-a**. ...O' S Ml I sz s 3V 33. e SkIIss gg|ig linnmill-in ~ .--------- - 1 * J-*MS3 SsSSss msMSs ISSfsg Sglggs gsg j J? % e M2%-* s3* ? fc* ****** SS^ swmr ; ----------------------------- . . (3 ,, "3 S5S2SI |5| i Time 1 Available i j . ` --------------------- ----------------- ---------- a w > SSiSSS SSSS^ -I s a-tSo,3'*t2^2a *3k, 1^ 1 1 ----------------------------------------- 1' !!! !!?? !!!!^ 1 ----------- --- . - s 4 A fr, 1* " s!i Him siHii min mm m ^ CiQ S- 2 1 b55 L -- sZJ *f J ss565i IS |MMM IISIII ?3 Olbo=> 3 "l,m 38 SKi SllliS SilSii |i H ~ 392 CHAPTER 16 ; , 1 1954 Guide: 2. Liquid and Gaseous Fuels. The combined efficiency of boiler, furnace and burner ! is the ratio of the heat absorbed by the water and Bteam in the bojler per pound or cubic foot of fuel, to the calorific value of 1 lb or cubic foot of fuel, respectively. 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 firing, 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 t - 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. ' . - "V ' . Assume that an installation has the following loads determined in' accordance j. with the section Selection of Boilers: . r Net Load. ....................................................... 1000 sq ft of steam radiation .: Piping Tax....................................................... 200 sq ft of steam radiation : DPeicskigunp LAollaowd.a..n..c..e......................................................:......................' 1229400 ssqq fftt ooff sstteeaamm rraaddiiaattiioonn t !; Maximum or Gross Load................................. 1440 sq ft of steam radiation >i A b, o.iler that i.s j_ust. large enough to carry this system might be said to.1 have a net load rating of 1000 sq ft, a design, load rating of 1200 sq ft, or,a-j gross load rating of 1440 sq ft, depending on the basis on which the boiler:-; is rated. i' On a net load basis the boiler would be rated 1000 sq ft of steam radiaticfo and would have sufficient excess capacity to supply the normal piping anit pickup load. Net I--B = R Ratings, SBI Net Ratings, and Net Load?' Ratings of the Heating, Piping and Air Conditioning Contractors Naiiand_ Association are established on Hus' basis. ; y On a design load basis the boiler would be rated 1200 sq ft of steam radia tion and would have sufficient excess capacity to supply the pickup tij&L It would be of adequate size for a system in which the sum of the net loaa, and the piping heat loss did not exceed 1200 sq ft of steam radiation. Th| SBI Ratings shown in columns 1, 2, 3, 10, 11 and 12 of Table 2 (not to b| confused with SBI Net Rating) are established on a design load basis-Vv, On a gross output basis of rating, the boiler would be rated 1440 sq ft . steam radiation and would be of adequate size for a system in which th^- sum of the net load, piping load, and pickup load did not exceed 144() s? . ft of steam radiation. Gross 1 = B=R Output and A.G.A. Ratings#8! esItanbltihsheeddeotenrma ingraotsiosnouotfpbuot iblearsirsa. tings`, the Gross Output is the quantity, of heat available at the boiler nozzle, with the boiler normally, insulate# and when Operating under limitations stipulated in the code or methodjtfo which the boiler is rated. The boiler may be capable of producing greater nozzle output, but in doing so would exceed some of these limitation - L.& Heating turners, furnaces. Space Heaters 393 SELECTION OF BOILERS General Factors The Maximum Load or Gross Load on 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 convection coils) to be installed. The connected radiation is determined by calculating the heat losses for each jraotoemd ihneaatccloosrsdeasncfoerwailtlhthdeatraoogmivsenreipnreCsheanptstetrhse.9t,o1t1aal nredq1u2ir.edThheeastuemmoisfstihone coaf ltchue- connected 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 heat in Btu per hour re quired to heat water for domestic use. , 1 = 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 tank capacity). For instantaneous coil installations the boiler capacity should not be less than required to heat 2 to 3 gal of water, 100 deg per min. See also Chapter 49. * 3. Piping Tax. The estimated heat emission in Btu per hour of the piping con necting the radiation and other apparatus to the boiler. As the heating industry as a whole is not entirely agreed upon piping tax allowances for different sites of installations, it is better to compute the heat emission from both bare and covered pipe surface in accordance with data in Chapter 28. In average house heating systems, it is common ni-a ri -------- ' - ' 4. Warming-Up or Pick-Up 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 con tents to operating temperature, and heating up cold radiation and piping. The factors to be used for determining the allowance to be made should be selected from Table 4. Table 4. Wakmi.n'g-up Allowances fob Hand-Fibed Low-Pbessube Steam anp Hot Wateb Heating Boilebs* b c _ DESIGN LOAD tRp`BmEffTmoSpMmTKWorlTraal.2,Ain>3) hto per Hour Equivalent Sqoan Feet atBadiatiood , Up to 100,000 om'OOO to 200,000 mcm t0 60.00 12nnoonto USOO.OOO ail000 t0 1.800,000 Above 1,800,000 Up to 420 420 to 840 840 to 2500 2500 to 5000 5000 to 7500 Above 7500 PKaCBSTAOx-CAPACirr to Add xoa WABidNO^Upe 65 60 55 50 45 40 lion of BuiMttt 13 ta^en ^rom the A-S.H.V.E. Code of Minimum Requirements for the Heating and Ventila ted in tfervnTnf8, that the second column has been added fox convenience in interpreting the design b equivalent square feet of radiation. rtONs, Vol 7$** Analysis in Starting Heating Apparatus, by Ralph C. Taggart (A.S.H.V.E. TransacReport of A.S.H.V.B. Continuing Committee on Codes for Testing and Rating * ^hd Fuel Boilers (A.S.H.V.E Transactions, VoL 38, 1930, p. 35); Selecting the Right Sire * 'This Crocker (Heating, Piping and Air Conditioning, March, 1932). .wben aatomnti,J[?/er5 to solid fuel boilers. A factor of 20 percent over design load is adequate " d24n Btu fud* are used. square foot. ;394 CHAPTER 16 I# 1954 Guide 4 Other items to be considered in boiler selection are: a. Efficiency with hard or soft coal, gas, 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 intermittent, or a combination of both. e. Convenience in firing and cleaning. /. Adaptability to changes in fuel and kind of attention. g. h. Height of water line. Miscellaneous items such as draft available, possibility of future extension, possibility of break-down, and head room in the boiler room. i. 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 manu facturers' catalogs. They may also be obtained conveniently from pub lished tables of I -- B = R ratings,6 or from recommendations of the Heating, Piping and Air Conditioning Contractors National Association,1 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 Sted - Boiler Institute, Inc. code, are intended to correspond with the estimated. Table 5. Practical Combustion Rates for Coal-Fired Helping Boilers Operating at Maximum Load on Natural Draft of fkm $ in. to 1 in. Water* ' V'- Heating Boilers, Furnaces, Space Heaters . 395 design load. When the heat emission of the piping is not known, the net load to be considered for the boiler may be determined from Tables 1 and 2. The difference 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 177 sq ft of heating surface, and having SB I net ratings (steam) of not more than 3,000 sq ft if mechanically-fired and 2,480 sq ft if hand-fired, are classified as residence size. An insulated residence boiler for oil, gas, or stoker firing may carry a net load expressed in square feet of steam radiation of not more than 17 times the square feet of heating surface in the boiler, provided the boiler has been tested in . accordance with the SB I Code for Testing Oil-Fired Steel Boilers at out put rates of 125, 150, and 175 percent of the SBI Net Rating. The SBI Net Rating (square feet steam) for hand-fired residence boilers is not greater than 14 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 a part of the net load. . Heating Surface and Grate Area Basis Where neither, the net load nor gross output ratings based upon perform ance 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 square foot) 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 maximum load including the warming-up allowance will be provided for by operating the boiler in excess of the design load, that is, in excess of the 100 percent rating on a boiler-horsepower 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: where H G CXFXE (1) G = grate area, square feet. E = required gross output of the boiler, Btu per hour (see Selection of Boilers). p = desirable combustion rate for fuel selected, pounds of dry coal per square foot of grate per hour (see Table 5). F = calorific value of fuel, Btu per pound. F = efficiency of boiler, usually taken as 0.60. l: Determine the grate area for a required gross output of the boiler of *a),000 Btu per hour, a combustion rate of 6 lb per hour, a calorific value of 13,000 "tu per pound, and an efficiency of 60 percent. 500,000 " 6X 13,000 X 0.60 107 8<1 f* mi^Id k*'er selected should have a grate area not less than that deter- suffi' ^ 9uation 1. With small boilers, where it is desired to provide *cient coal capacity for approximately an eight-hour firing period plus a 396 CHAPTER 16 1954 Guide 20 percent reserve for igniting a new charge, more grate area may be re quired depending upon the depth of the fuel pot. ' Gas-Fired Boilers After determining the net load for the installation, gas designed 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 33.3 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.G.A. output rating equal to the maximum output required. Detailed recommendations for selection of gas designed boilers are given in the A.G.A. publication, Comfort Heating.8 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, stok ing, 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 oh at least one side of every boiler for convenience of erection and for accessibility to the various damp ers, 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 die 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 exceeding 25-t0: 30 fps at maximum load is recommended, unless data are available to shoe that a higher velocity is satisfactory. See further data on pipe connection^1 to boilers in Chapters 21 and 22 and in the ASME Boiler Construction. Code for Low Pressure Heating Boilers. . Where a return header is used on a cast-iron sectionalIxnLer to distribute; the returns to both rear tappings, it is advisable to provide full size plugged -, tees instead of elbows where the branch connections enter the return tap;! pings. This aids in cleaning of sludge from the bottom of the boiler sec-y tions through the large plugged openings. An equivalent cleanout should be provided in the case of a single return connection. j&V Blow-ojf or drain connections should be made near the boiler, and soj arranged that the entire system may be drained of water by opening we..f drain cock. In the case of two or more boilers separate blow-off connepv; tions must be provided for each boiler, on the boiler side of the stop on the main return connection. . Water service connections must be provided for both steam and Heating Boilers, Furnaces, Space Heaters 397 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 ASME Boiler Construction Code for Low Pressure Heating Boilers. Smoke Breeching and Chimney Connections. The breeching or smoke pipe from the boiler outlet to the chimney should be air-tight 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 chimney. . 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 con tractor may be familiar with the boiler. All joints requiring boiler putty or cement, which cannot be reached after assembly is complete, must be finished as the assembly progresses. Five precautions that should be taken in all 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 freezing 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 ex pansion and contraction. 3. Direct impingement of too intense local heat upon any part of the boiler sur face, as with oil burners, should be avoided by protecting the surface with firebrick or other refractory material. 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 falls below a safe level, are recommended for me chanically-fired boilers. Boiler Troubles A complaint regarding boiler operation generally will be found to be due to one of the following: 1. The boiler fails to deliver enough heat. The cause of this condition may be; (o) poor draft; (b) poor fuel; (c) inferior attention or firing; (d) boiler too small; (e) irow ?er P'P'nK> (/) improper arrangement of sections; (g) heating surfaces covered no soot; (A) insufficient radiation installed; and (i) with mechanical firing, fuel "nnng equipment too small. j- The water line is unsteady. .The cause of this condition may be: (a) grease and show" der; (h) water column connected to a very active section and, therefore, not f actual water level in boiler; and (c) boiler operating at excessive rate of t0 ^ater disappears from the gage glass. This may be caused by: (o) priming due pease and dirt in boiler; (b) too great pressure difference between supply and 398 CHAPTER 16 1954 Guide return piping preventing return of condensation; (c) valve closed in return line; (d) connection of bottom of water column into a very active section or thin waterway; and (e) improper connections between boilers in battery permitting boiler with excess pressure to push returning condensation into boiler with lower pressure. 4. Water is carried over into steam main. This may be caused by: (o) grease and dirt in boiler; (6) insufficient steam dome or too small steam liberating area; (c) outlet connections of too small area; (d) excessive rate of output; and (e) water level carried higher than specified. 5. Boiler is slow in response to operation of dampers. This may be due to : (a) poor draft resulting from air leaks into chimney or breeching; (6) inferior fuel; (c) inferior attention; (d) accumulation of clinker on grate; and (e) boiler too small for the load. 6. Boiler requires too frequent cleaning of flues. This may be due to: (a) poor draft; (fe) smoky combustion; (c) too low a rate of combustion; and (d) too much excess air in firebox causing chilling of gases. 7. Boiler smokes through Jure door. This may be due to: (a) defective draft in chimney or incorrect setting of dampers; (6) air leaks into boiler or breeching; (c) gas outlet from firebox plugged with fuel; (d) dirty or clogged flues; and (e) improper reduction in breeching size. 8. Low carbon dioxide. This may be due on oil burning boilers to: (a) improper adjustment of the burner; (b) leakage through the boiler setting; (e) improper lire caused by a fouled nozzle; or (d) to an insufficient quantity of oil being burned. Cleaning Boilers AH boilers are provided with flue .clean-out 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 deter mine when cleaning is necessary. The grease used to lubricate the cutting tools during erection of new pijy ing systems serves as a carrier fpr 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, preventing 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 1'} in. nominal pipe size with outlet extended to within 18 in. of the floor or to sewer, inserting a valve in line close to boiler Bring the water line to center of outlet, raise steam pressure, and while fire is burning briskly open valve in blow-off line. When pressure recede^ close valve and repeat process adding water at intervals to maintain proper" level. As a final operation bring the pressure in the boiler to about 1? lb, close blow-off, draw the fire or stop burner, and open drain valve. After boiler has cooled partly, fill and flush out several times before filling it to proper water level for normal service. The use of soda, or any alkali, vinegar or any acid is not recommended for cleaning heating boilers be cause of the difficulty of complete removal and the possibility of subsequent injury, after the cleaning process has been completed. <;. Effective insoluble compounds have been developed and are availably- Special instructions on the proper cleaning compound and directions for i; use, as given by the boiler manufacturer, should be carefully followed-*.- 4s- Care of Idle Heating Boilers Heating boilers are often seriously damaged during summer ,T,onM:' due chiefly to corrosion resulting from the combination of sulfur in- ;i Heating Boilers, Furnaces, Space Heaters 399 soot with the moisture in the cellar air. At the end of the heating season the following precautions 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 some one may in advertently 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 glass if necessary.' 7. Remove any rust or other deposit from exposed surfaces by scraping with a wire brush or sandpaper. After boiler is thoroughly cleaned, apply a coat of preservative paint where required to external parts normally painted. 8. Inspect all accessories of the boiler carefully to see that they are in good work ing order. In this connection, oil all door hinges, damper bearings, and regulator parts. WARM AIR FURNACES Warm air heating furnaces of a number 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 heat distribution--these are either gravity or me chanical (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 occasionally high temperature steel alloys. 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 producing air flow spends upon the difference in density between the heated air leaving the op of the casing and cooled air entering the bottom of the casing. Since tos gravity head is relatively low, the furnace must have low internal restance to the flow of air, and relatively large areas must be available for vkf ClrCulation within the furnace casing. It is common practice to pro aPproximately 50 percent free air area through gravity type furnaces. ce f11??068 -^0r ravit.y type systems are available in designs suitable for fan ^ heatin6> P'Pe'ess furnace, or unit floor furnace installations. Booster cr are .sometimes used in conjunction with gravity design systems, to insizeiTf<arc.u^atin- Where a fan is to be used with a furnace casing strict, tvf ^rav*ty a'r flow, some form of baffling must be employed to reagaij, Jhe free area within the casing and to force impingement of the air l heating surfaces. Where square casings are used, the comers be baffled. 400 CHAPTER 16 1954 Guide Mechanical Warm Air Furnaces Mechanical or forced warm air furnaces include fans or blowers as in tegral parts, for the purpose of circulating the air, and usually include air filters. Centrifugal fans with either backward or forward curved blades are the type 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 34. For maximum efficiency and life under operating conditions, filters should not be subjected to a temperature in excess of 150 F. Filters should have at least 80 percent average efficiency on an 8-hr test at a maximum resistance of 0.25 in. of water. Filter resistance rises rapidly with the accumulation of dirt, and may reduce the air circulation over heating surfaces. In domestic fur naces, the maximum velocity, based on nominal filter area, should not exceed 300 fpm. Fuel Utilization A combustion rate of from 5 to 8 lb of coal per (square foot 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 available draft. . In residential furnaces for coal burning, the ratio of heating surface to grate area will average about 20 to 1; in commercial sizes the ratio may-be as high as 50 to 1, depending on fuel and draft. Furnaces may be installed singly, each furnace 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 usually designed for blow-through install lations so that the pressure in the air space is higher than that in the combustion chamber or flues. The National Warm. Air Heating and An Conditioning Association has prepared a Tentative Code for Testing aild Rating of Oil-Fired Furnaces. Compact fan-fumace-burner units are available, suitable for basement, closet, or attic installations. ,-,'t Gas-fired forced air furnaces should conform in construction and per formance to A.G.A..Approval Requirements. ; Heavy Duty Fan Furnaces ; Fan furnaces for large commercial and industrial buildings, churches, schools, etc., are available in sizes ranging from 300,000 to 6,000,000 Btu per (hour) (unit). Heavy duty furnace heaters may be arranged in bak tery combinations of one or more units. .^ Most manufacturers of heavy duty furnaces rate their furnaces in Btu;. Heating Boilers, Furnaces, Space Heaters - 401 per hour, and also in the number of square feet of heating surface. Con servative practice indicates that at no time in the heating-up period should the furnace surface be required to emit more than an average of 3500 Btu per square foot. A higher rate of neat emission tends to increase the heat loss up the chimney, and raise fuel consumption, to shorten the life of the furnace, and to overheat the air. The ratio of heating surface to grate area of furnaces for this type of work should never be less than 30 to 1 and, as indicated previously, may run as high as 50 to 1. Control of temperature is secured through (1) controlling the quantity of heated air entering the room, (2) using mixing dampers, or (3) regulating the fuel supply. . . The design of heavy duty fan furnace heating systems is in many re spects similar to that of the central fan heating systems described in Chap ter 30. Ducts are designed by the method outlined in Chapter 32. MATERIALS AND CONSTRUCTION Cast-Iron Furnaces Cast-iron furnaces are made in a multiplicity of designs or shapes. For solid fuels they are-generally of round sectional construction, the sections being.cemented or bolted together. Various types of radiators for second ary convection heat transfer are employed. Such radiators are of the circular, doughnut type, or tubular type. - Cast-iron is frequently used in the construction of gas or oil-fired fur naces, designs varying considerably with two general types in common use: multi-sectional type, and those with single combustion chambers having auxiliary secondary surface. Cast-iron 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 minimum sectional thickness of f in., and effectively resist high temperatures and corrosion. They usually have a fairly large heat capacity because of their mass, which Provides a distinct fly wheel or carry-over heating effect. Steel Furnaces Formed sheet steel construction is frequently used in furnace design. Welding, riveting, or both are used to join the formed metal. The use steel castings, however, is rare, because of the cost, and because high stresses are not encountered in normal furnace construction. Types of design employed vary greatly, although perhaps the most common type consists of a drum and circumferential or rear radiator. Steel gas furnaces P^y also be sectional in design, or may be combinations of common comustion chambers and sectional or tubular radiation surfaces connected to a "fe gas collector. teel furnaces are made in capacities ranging from 40,000 Btu per hour to Pacifies as large as 600,000 Btu. Steel furnaces have low heat capacities of their relatively low mass and, therefore, deliver heat rapidly FURNACE RATING air furnaces are generally rated in Btu per hour output at the et (point of heat generation) or at the register (point of heat delivery). 402 CHAPTER 16 1P54 Guided Rating Equations for Gravity Warm Air Furnaces9 ,tO? . Until a method of testing and rating gravity warm air furnaces has beenW developed, the following empirical rating equations are recommended by?J" the National Warm Air Heating and Air Conditioning Association. Gravity warm-air furnaces of conventional. design, having ratios (off:' heating surface to grate area) of 15 to; 1 or greater, and having a ratio tfgf casing area to face area not less than ,0.4, are rated by the following equarS) tions: . 1. Hand-fired furnaces converted to Stoker, Gas, or Oil Firing. " Bonnet Capacity in Btu per hour = 1785 X S X 1.333 (2);' vlft 2. Hand-fired furnaces, with ratios of healing surface to grate area greater than 15,to l and less than 25. to 1. " .. Bonnet Capacity in Btu per hour = 1785 X S X 1.333 (3) 3. Hand-fired furnaces with ratios of healing surface to grate area in excess of 25 tat:. ' ,, , -J4 Bonnet Capacity in Btu per hour = 1785 X 25 X G X 1.333 (4) v where S = heating surface, in square feet. . ' ' `"fe G = actual grate area, in square feet. The Register Delivery Rating is equal to 0.75 x (Bonnet Capacity). TEal* Leader Pipe Rating in square inches, formerly used as a rating unit, may be;) found by dividing the Register Delivery Rating by 136. vfj|; Heating. Surface of Furnace ..Jag Prime beating surface is defined9 as surface above the top of the grate^ having hot gases or live fuel on one side and circulating air over the other, sidft in all cases is measured on the exterior or air side. The.areas of the outei3 casing, the inner liner, and any radiation shields shall not be considered as heating surface. , In determining the amount of heating surface, extended surfacesjsst- considered to be prime heating surface subject to the following limitations)^ fv. 1. Extended heating surface may consist of fins, ribs, webs, lugs, or other,.pr?;, jections from the prime heating surface. Projections less than j in. thick base, and extending more than 1 in. from the prime surface are classified as lin3f:r'' 2. Integral fins are continuously welded to, or cast as a part of, the prime heabhjl surface. Both sides are included as heating surface, subject to the following'allo^f, ances: ' Distance from Prime Surface . 1st inch 2nd inch 3rd inch Over Ratio of Effective Area to Total Area.............................. 0.40 0.30 0.20 None.'! .............7$ 3. Non-integral fins are spot welded to, or otherwise held in line contact : prime heating surface". Both sides are included as heating surface, subject; following allowances: . jp&W Distance from Prime Surface . Ratio of Effective Area to Total Area...................... 1st inch 0.30 2nd inch 0.20 3rd inch 0.15 Heating Boilers, Furnaces, Space Heaters 403 4. In the case of ribs, webs, or lugs more than J in. thick at the base and extending less than 1 in. from the prime surface, the entire surface in contact with circulating air in included as heating surface. 5. In the case of ribs, webs, or lugs more than 1 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 heating surface. The portions projecting beyond 1 in. are treated as integral fins. Grate Area Grate area is defined9 and treated for purpose of rating as follows: 1. The nominal grate area is defined as the total cross-sectional area of the bottom of the firepot. In steel furnaces the nominal grate area is the cross-sectional area inside the firebrick lining. 2. The actual grate area, used for calculating the ratios of heating 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, shall be deducted. (2) If separate, solid projections ex tend from the firepot towards the grate, the areas of any portions of these projections extending inside of a circle, the diameter of which is 3 in. less than the diameter of the bottom of the firepot, shall 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 making any necessary deductions. Ratings for Forced Air Furnaces - For solid fuel burning, forced air furnaces having bonnet capacities between 80,000 and 250,000 Btu per hour, no standard method of test has been accepted, although eventually such codes will be developed. The National Warm Air Heating 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 xSi 1.177 (5) 2. Hand-firedfurnaces, with ratios of heating surface to grate area greater than 15 to l and less than 25 to l. Bonnet Capacity in Btu per hour =. 2265 x S x 1.177 (6) 3. Hand-fired furnaces with ratios of heating surface to grate area in excess of 25 to 1. where Bonnet Capacity in Btu per hour = 2265 x 25 x G x 1.177 (7) 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 f]l0Wjng testing and rating codes have been generally accepted in me industry: Wn"TrCla* Star/lard CS-109-44 for rating solid fuel-burning, forced-air furnaces ratirio^ outputs of 80,000 Btu per hour or less. This provides a method of 4 sms0 oal-fired forced-air furnaces by test. the V Vltative Code for Testing Oil-Fired Furnaces. This code has been adopted by i'trnacesb0^trarWl ^^ an<^ ^tr Conditioning Association for rating oil-fired ttader* i^n?eriCan Association method of rating gas-fired furnaces on performance Qas Appfja" This `s described in the Approval Requirements for Central Heating 404 CHAPTER 16 1954 Guide Commercial Standard US-61 is a method of rating oil-burning floor furnaces by test. . /. Commercial Standard CS104-49 is a method of rating warm air furnaces equipped with pot-type oil 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 codes10 which regulate construction and installation of furnace equipment. The yardstick of the National Warm Air Healing and Air Conditioning Association provides criteria for evaluating a furnace design and installation against industry accepted standards. . FURNACE EFFICIENCY Rating formulas of the National Warm Air Heating and Air Conditioning Association are based on 55 percent efficiency 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 oil-fired forced-air furnaces. Gravity gas furnaces approved by the Ameri can Gas Association are assigned a rating based on 75 percent efficiency. All forced-air gas-fired furnaces approved 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. > i. a. Heat transfer rates of 2,000 to 4,500 Btu per (hour) (square foot) of heating surface may be obtained without unduly high metal temperatures. b. Fins, pins and bosses are frequently used to add surface and to break down., superficial gas films, both on gas-to-metal and metal-to-air surfaces. c. Surface and stack (flue gas) temperatures are good indications of the amount ,, and effectiveness of the heating surfaces. 2. Safe and efficient combustion offuel. - a. Proper mixture of fuel and air is necessary for efficient combustion. This necessitates careful attention to the design of grates, nozzles, burners, air inlet areas and location, and combustion chamber baffling. . !e. 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. 1. c. Total draft loss through appliances should not exceed that available frpin;' chimneys which would normally be obtainable in the size of building whicji .. the appliance will supply with heat. , X. d. The use of ignition safety devices such as safety pilots, hold-fire controls;:' and the like is recommended. 3. Fa.ueWl citahpascoiltiydoffuaeplsplaiadnecqeu.ate coal capacity should be provided for at leastA ' hr of operation at the maximum rated combustion rate. ` 1: V,: 4. Adequate circulation of air over heating surface. a. In gravity furnaces, free air space between casing and heat exchanger should", b. Fbeorgcreedataeirnofuugrnhatcoe pdeersmigint frmeeusfltowincoluvdeer aflal nssurhfaacveisn.g proper capacity'^, suitable performance characteristics. Internal static pressures must be minimized without losing the advantages of high velocity circulation or&, the heat exchanger surfaces. . .. c. The air flow over the heating surface must be directed to obtain maxinuWV efficiency and to eliminate hot spots and air noises. F'.'-' d. Air velocities at bonnet should not be much in excess of 1,000 fpiri, temperature distribution at the furnace outlet should be uniform witnw approximately 30 deg. ' Heating Boilers, Furnaces, Space Heaters 405 5. Durability. a. A minimum metal weight for gas-fired heat exchangers is established as No. 20 U.S. Gage for plain carbon steel by the A.G.A. Approval Requirements for Central Heating Gas Appliances, with some municipal codes specifying 18 gage. Cast-iron sectional thicknesses of J in. to } in. are recommended; b. Added strength and reinforced designs may be required to preclude damage in shipment, burning out from overfiring, or corrosion from condensation. c. Maximum heat exchanger surface temperatures which may be used vary with the metal. The American Gas Association Approval Requirements for Cen tral Heating Gas Appliances specify a maximum of 875 F for cast-iron or steel gas furnaces, and the National Bureau of Standards CS 109-44 Code for Forced Air Solid Fuel-Burning Furnaces specifies 1000 F as a maximum surface tem perature. .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 to burn those who touch them, or to create fires. 6. Serviceability. a. Those parts of the furnace which may be subject to soot, fly-ash, or conden sation deposits should be accessible for cleaning. b. Parts which may require adjustments or replacements, such as grates, baffles, liners, controls, should be removable. c. Furnaces should be so designed that they can be installed with a minimum of difficulty. 7. Control. , a. Thermostatic controls of various types should be used to correlate space " temperatures With unit operation. b. Controls should be provided wherever possible, to prevent the occurrence of excessive temperatures or other conditions in any part of the unit which might cause unsafe operation. . 8. General design considerations. a. Furnace casings are normally constructed of formed and painted sheet steel or of galvanized iron. The casing should be protection from excessive radia. . . tion losses and 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 I in. to 1$ in. from the outer casing. b. The hood or bonnet of the casing above the furnace should be as high as base ment conditions will allow, to form a plenum chamber over the top of the 1 furnace. This tends to equalize the pressure and temperature of the air leaving the bonnet through the various openings. It is generally considered advisable to take off the warm air pipes from the side of the bonnet near the 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 l in. flange is normally used for this purpose. 4. 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 provided to insure their proper location. 6' T*16 ue 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 pr^paPra^ng pans are usually located in the outlet air. There is a RjSent trend toward heating the water. Equipment for doing this may placed^ - sPrays> or ** may take the form of water circulating coils humid'fT'ti1'11 the combustion chamber, and connected by pipes to the float A - Pans where a constant water level is maintained by some separate device. All humidifiers require provision for removal of dirt and lime. 406 CHAPTER 16 1054 Guide ^ 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 exchanger surface is exposed directly to the room atmosphere, and the generated heat is dissipated primarily by radiation. A circulating 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 unvented 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 magazine-feed heater includes a deep reservoir of fuel to lengthen the attention intervals. In a true magazine feed heater 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 impos sible to attain for any solid fuel under normal usage, although self-feeding may be obtained with wood and some free burning coals. Thus, a maga zine-type space heater is essentially a deep surface-fired heater, its principal difference being increased fuel capacity. Materials and Construction There is no accepted code governing the construction of solid fuel burn ing 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 air-tight heaters designed as low-cost wood-burning units with little con sideration for long life, and stoves were priced on a poundage basis. The present trend is toward fabricated steel parts and welded assemblies, al though cast-iron is still used for grates, firebox liners, and parts subject to high temperatures. Refractory firebox liners are also used quite exten sively. Formed sheet steel is used predominantly for the outer jacket of circula tor heaters, although heaters with outer casings formed from cast-iron are still readily available. Circulator cabinets normally have surfaces finished with a porcelain 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 the method of testing and ratin? solid-fuel space heaters. A tentative procedure, TS-3443, has been issued by the Division of Trade Standards, National Bureau of Standards, buy? based on use of anthracite 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 hea. Heating Boilers, Furnaces, Space Heaters 407 losses: (1) loss due to moisture in the fuel, (2) loss due to heat in the dry flue gases, (3) loss due to unburned carbon monoxide, and (4) loss' due to unburned combustible in the ash and refuse, are measured by test. The total of these four measurable losses, plus an assumed value for unac counted for losses, are then subtracted from the heat input. The dif ference multiplied by the burning rate in pounds per hour is the heater output. When using 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 incomplete, a value of 12 percent of the heat input has been determined as representing the losses due to smoke and unburned hydrocarbons for a surface-fired heater, when burning 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 overheating of floors and walls. Although there are no industry-accepted standards by which floor and wall temperatures may be determined, some indication of heater performance, with regard to overheating, may be found by the use of the corner booth test arrangement de scribed in National Bureau of Standards Commercial Standard CS 103-43 and Under writer's Laboratories 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 exchanger of circulating heaters, to permit free air flow over all surfaces and maintain a suitably low casing temperature. 4. Protection of all metal parts from deterioration due to high temperature. This Bay 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 coatlngs, (d) directing air against hot spots. 5. Proper admission of secondary air to complete the combustion process. Care should be taken to prevent this air from also functioning as primary air. 6. Strengthen assembly to prevent transportation and use damage. Considerable work has been directed in the past few years towards im provement of the performance of bituminous coal-fired space heaters, with Particular reference to smokeless operation under conditions of normal operation such as obtained in homes. A recent paper describes the smoke less coal heater developed by Bituminous Coal Research, Inc., wherein ?okeless combustion is obtained by admitting secondary air through a narrow slot, extending from side to side, above the edge of the fuel bed f the gas leaves to enter a vertical gas passage.11 Complete mixing oi the volatile material, released from the coal in the magazine, with the secondary air supplied is obtained as both streams pass under the bottom i the arch. Complete combustion results from this intimate mixing in a on which maintains itself at high temperatures even during banking Periods. OIL HEATERS of^Pori^ng pot-type oil beaters consist of: (1) a metal pot in the bottom inch the oil is vaporized, the vapors burning; aatt or uneuaari tvhuec tUoUpJf Uo1f tIUhCe 408 CHAPTER 16 1954 Guide pot; (2) a secondary combustion 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 the 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 the 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 varporized, then mixed with air introduced through suitably lo cated ports and burning at the top of the pot or perforated sleeves. Such heaters are designed to bum No. 1 oil (See Table 4, Chapter 14) or kero sene (coal oil). .At no time should.oil heavier than that for which the burner is designed be used, as heavier oils may cause excessive carboniza tion in. the burner or fuel feed line. Materials and Construction Formed sheet steel and welded assemblies are used primarily in oil heater construction. Standards governing construction which have been generally accepted are: 1. Commercial Standard for Flue-Connected Oil-Burning Space Heaters equipped' with Vaporizing Pot-Type Burners, CS101-43 (National Bureau of Standards). - 2. Standard for Oil-burning Stoves, Subject 896 (Underwriters' Laboratories, Inc.). 3. Standard for Construction and Performance of Oil Burners for Installation in. Stoves and Ranges, Subject 865 (Underwriters' Laboratories, Inc.). Some States or municipalities have codes which apply locally, but these, 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 stand ard 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: '" H, = A - B (8Xf and E = Hr/A where A = total heat of fuel used. B = heat lost in flue gases. H, = net heat delivered to the room. E = unit efficiency. (9)i . 'HI j'fr \o The following minimum performance requirements are stipulated: 1. Adequate provision for ease of lighting and insurance against loss of ignitiop prior to heating of burner. - 2. Ease of operation of controls. Heating Boilers, Furnaces, Space Heaters / 409 3. Proper operation of burner without excessive carbonization 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 are: . and1.aPirrolopcekr. pitch of oil lines from the sump to th.e. burner, thus preventing vapor. 2. Proper positioning of the oil sump or constant-level valve to maintain the proper oil level in the burners, if factory assembled. , . .: 3. Tight construction, not only of oil lines, but of oil tank, sump, and burner to prevent a hazardous condition due to oil leakage. 4. Provision for leveling and aligning the entire heater for maintenance of proper . operation. If a separate fuel tank is used, the heater should have provision for secure fastening to the floor to prevent excessive strairron oil supply line, and the conse quent 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 tank to prevent excessive oil temperatures. ' /, 7. All metal parts subjected to the corrosive action of the oil shall be made of non- corrodible metal, or of metal suitably coated to resist corrosion. 8. The heater should have suitable baffling or insulation to prevent overheating of Boors and walls. 9. Strength in assembly to prevent transportation and use damage. GAS HEATERS Vented gas heaters are defined as those capable of removing 90 percent of the flue gases through a single flue outlet. All heaters having a gas in put rating in excess of 50,000 Btu per hour must be of the vented type in order to meet ASA Approval Requirements for Gas-Fired Room Heaters.1* 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 gas. 2. Yellow Flame Burner type in which secondary air only is depended on for the combustion of t--h---e--&g<-VaJs. . Materials and Construction . __ ,-t,vux*vU UU IUC LUO . Standards covering materials and accessories used in the construction of gas heaters are described in ASA Approval Requirements for Gas-Fired Room Heaters12 and in applicable Listing Requirements.13 : 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,1* based on the total heating value of the gas. Vented space heaters having "put ratings of 20,000 Btu per hour or less are required to have a heating efficiency of not less than 65 percent.12 These efficiencies are based upon me following equation: Cohere tl e, 100- -- X 100 9 (10) 7 - hourly gas heat input, Btu per hour. Rt = heat above room temperature carried away by the flue products, Btu per hour. " heating efficiency, percent. 410 CHAPTER 16 1954 Guide 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 sizes and locations so that the flame will not lift, float, or flash back, and be excessively noisy in operation. 2. Proper venting of combustion chamber for relief of forces resulting from igni tion of an explosive mixture of gas and air. 3. Protection of valve handles to prevent excessive temperature rise during opera tion. 4. Insulation and baffling of heater to prevent over-heating 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 17, Chimneys and Draft Calculations. In all cases, it is recom7 mended that installation be made in accordance with the current National Building Code. REFERENCES 1 See A.S.H.V.E. Transactions, Vol. 35, 1929, pp. 332 and 332. `See A.S.H.V.E. Transactions, Vol. 36, 1930, p. 42. * See A.S.H.V.E. Transactions, Vol. 37,1931, p. 23. * See A.S.H.V.E. Transactions, Vol. 44, 1938, p. 366. 4 I=B=R Testing and Rating Code for Low Pressure Heating Boilers, 1950 (Instil tute of Boiler and Radiator Manufacturers). >I=B=R Ratings for Cast-Iron Boilers (Institute of Boiler and Radiator Manu facturers). 7 Engineering Standards, Part II, Net Square Feet Radiation Loads in 70 Deg Fahr, Recommended for Low Pressure Heating Boilers, 1948 (Heating, Piping and Air Conditioning Contractors National Association). 8 Comfort Heating, 1938, pp. 35 to 39 (American Gas Association). Gravity Code and Manual for the Design and Installation of Gravity Warm Air Heating Systems, Section No. 5, Third Edition, Jan. 1947 (National Warm Air Heat- ing and Air Conditioning Association). ! 10 Recommended forms for municipal installation and fire codes are included id Manual 7--Code and Manual for design and Installation of Warm Air Winter Air Conditioning Systems, Second Edition, 1947 (National Warm Air Heating and Aij Con11dTithioenDinegvAelsospomcieantiot on)f.a Design of Smokeless Stove for Bituminous Coal, by B. A. Landry and R. A. Sherman, presented at the 1948 Annual Meeting of the ASMS. ** American Standard Approval Requirements for Gas Fired Room Heaters, ASA* . Z21.ll, 1950 with addenda Jan. 1, 1951 (American Standards Association). ;;; u American Standard Listing Requirements for: Automatic Pilots, Z21.20, 1951,, Gas Appliance Thermostats Z21.23,1941, Domestic Gas Pressure Regulators, Z21 -IB. 1936, with addenda effective June 15,1935, July 8,1938, Automatic Main Gas-Control Valves, Z21.22, 1949 (American Standards Association). CHAPTER 17 CHIMNEYS AND DRAFT CALCULATIONS Theoretical Draft; Factors Affecting Required Draft; Industrial Chimneys, Available Draft, Short Chimneys Determining Chimney Size; Residential Chimneys, Available Draft, Determining Chimney Size; Draft Requirements of Appliances; Chimneys for Gas Heating; Recommendations of the National Board of Fire Underwriters; General Considerations ADRADP to the layman, is a current of air, and the draft of a furnace or boiler is the current of air which flows through the firebox and furnishes the oxygen for combustion. To the engineer, however, the word draft has come to mean the pressure difference which causes this current of air to flow. The engineering concept of draft will be used in this chapter; hence, draft will be defined as a negative differential pressure, constituting the absolute pressure at some .point in the flue, less the absolute atmospheric pressure. The opposite of draft will be called positive pressure and will be defined as a positive differential pressure. . Draft is usually measured in inches of water. It is most commonly measured at the. thimble, where the breeching enters the chimney proper, although it may be measured in the firebox, the smoke breeching, the base of the chimney, or elsewhere, depending upon the type of chimney instal lation. Draft may be classified as either natural or mechanical, depending on whether it is produced by a chimney or by a blower. . Mechanical draft is further classified as induced or forced, depending on whether the air is drawn through or forced through the combustion chamber. THEORETICAL DRAFT If the air in one of two equal chimneys is heated, while that in the other is not, the air in the heated chimney will be lighter than that in the other chimney, and a manometer or other pressure gage connecting the two at the bottom will indicate a pressure difference, called natural draft. The pressure of the air at the tops of the two chimneys will be equal, so that the pressure difference between them at the bottom will depend only on their height and the difference in density of the air they contain. As fne density of the air in either chimney is inversely proportional to its absolute temperature, the difference in pressure between them at the bot tom will be proportional to their height and to the difference between the reciprocals of the absolute temperatures within them. As the pressure at the bottom of an unheated (and uncooled) chimney ''nil be the same as that of the air outside, the unheated chimney can be dropped from the foregoing illustration. The manometer reading will be the same if its free connection is left open to the atmosphere. These considerations, in conjunction with those of barometric pressure and the difference in density of flue gases from that of air, lead to the folowing formula: D, = 2.96 HB. (Wo In _ IFA rj (I) 411 412 CHAPTER 17 1954 Guide where H = height of chimney, feet. Bo existing barometric pressure, inches of mercury. Wo -- density of air at 0 F and 1 atmosphere pressure, pounds per cubic foot. Wo = density of flue gas at 0 F and 1 atmosphere pressure, pounds per cubic foot. To = temperature of air surrounding the chimney, Fahrenheit degrees absolute. To = average or effective temperature of the gases in the chimney, Fahrenheit degrees absolute. , . The quantity Dt, found by the formula, is the pressure difference be tween the gas inside and air outside of the chimney, in inches of water, when no. flow occurs in the chimney. The quantity is variously known as U 3 1U l-J s,w __ POUNDS OF COAL BURNED PER SQ FT OF GRATE SURFACE PER HOUR Fig. 1. Draft Required at Diffebent Rates of Combustion fob Vabious Kinds of Coal the theoretical; draft, the static draft, or the computed draft. It is very- useful in predicting and analyzing chimney performance, but it is seldom, if ever, attained in an actual chimney because of the friction incident to gas flow and the effects of wind. .if-; The efficiency of a chimney is defined as the ratio of the observed dr^t or available draft, produced by the chimney for a given inlet temperature and flow rate, to the ideal draft that would be observed if the flue gas* traversed the chimney without cooling and without friction. The chimney efficiency may be calculated as follows: rrf . .t-.fij. final measured draft Efficiency = ideal draft calculated from the inlet temperature FACTORS AFFECTING REQUIRED DRAFT - Before the proper chimney can be selected for an installation, the quired draft of the combustion unit must be known. The required' dr<U is, of course, equal to the sum of all the resistances to gas flow from ash pit door to, and including, the chimney connection. _ Fig. 1 presents information on the fuel-bed draft loss for various ku^3 Chimneys and Draft Calculations 413 . of coal burned at different rates. Rough generalizations 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 design' 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 32.) 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 breech ings or flue pipes. For uninsulated surfaces this probably can be ade quately estimated by assuming a loss of heat from the flue gas of 3 Btu. per (hr) (sq ft) (Fahrenheit deg temperature difference between the gases and surrounding air). . INDUSTRIAL CHIMNEYS Chimneys can be classified as residential and industrial, the chief dif ference being their sizes and the types of draft.. Chimneys over approxi mately 1-) ft in diameter are in the industrial chimney class, and their re quirements should be . treated accordingly. The majority of industrial chimneys operate under induced or forced draft, resorting to natural draft operation only in the case of emergencies. They are built of brick, con crete, or steel, depending upon economy and the type of installation needed. Proper height is of importance because of removal of waste products, inas much as the products of combustion are often deflected downward around the chimney and, with the large amount of gases that are exhausted to the atmosphere through the industrial chimney, downwash can be very ob jectionable.1 : AVAILABLE DRAFT FOR THE INDUSTRIAL CHIMNEY The available draft, Do, for large chimneys and stacks has been estimated with apparent satisfaction in the past by means of formulas which in effect deduct an estimated friction 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 pro cedure results in formulas for the available draft as follows: For a cylindrical stack'. Do = 2.96HB,(\W7\o, To) 0.0012/&W*TofL D*BoWo and for a rectangular stack: (3) where (Wo _ 1E\ _ 0.000388iy*?',/L(x + y) V T To) i.xy)>BoWo (4) = available draft, inches water gage. H -- height of chimney above inlet, feet. Bo -- existing barometric pressure, inches of mercury. Wo = density of air at 0 F, 1 atmosphere pressure. Wo = density of flue gas at 0 F, 1 atmosphere pressure. To. = temperature of atmosphere, Fahrenheit, absolute. 414 CHAPTER 17 1954 Guide To = 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. . x 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 Bo, 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 elevationT .: 2. The unit weight of a cubic foot of chimney gases at 0 F and sea level barometric pressure is given by the equation: ' Wo = 0.131C02 4- 0.0950* + 0.0S3N* (5) In this equation CO:, Ot and Ns 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 Wc may be assumed at 0.09. The density effect on the chimney gases, $ue to superheated water vapor resulting from moisture and hydrogen in the fuel, or due to any air infiltration in the chimney proper, is disregarded. Though water vapor content is not disclosed by Orsat analy-! sis, its presence tends to reduce the actual weight per cubic foot of chimney gases.., 3. The atmospheric temperature is the actual observed temperature of the outside, air at the time the analysis of the operating chimney is made. The mean atmospheric temperature in the temperate zone is approximately 62 F. ` 4. The chimney gas temperature decreases from the breeching connection to the top1 of the stack. This drop in temperature depends upon the material and construction7 of the stack, its tightness or freedom from leaks,.its area, its height, and the velocity! of the gases 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 general equation covering all these variables has been suggested, but from observations on chimneys varying in diameter from 3 to 16 ft, and in height from 100 to 250 ft, Equation 6 was deduced :* -[(tT-i] H-3 (6); i( where Tx -- temperature at the center of the connection from the breeching, Fahrenheit. degrees, absolute. Ht, = the height of the stack above center line 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 0.016 for the condij tions 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, w- gardless of the materials of construction, becomes covered with a layer of soot, and thus the coefficient of friction has been taken the same for all types of chimneys and generally constant for all conditions of operation. For reasons of simplicity aiith. convenience to the reader, this constant value of 0.016 has been employed in the ae-i- velopment of the various special equations and charts shown in this chapter. In important large chimney design, especially when the construction or the mate rials are unusual, it is recommended that use be made of the Reynolds number',l?- determining the friction factor, /. . ' The following problem illustrates the use of Equation 3: Example 1: Determine the available draft of a natural draft chimney 200 ft 15, Chimneys and Draft Calculations 415 height and 10 ft in diameter, operating under the following conditions: atmospheric temperature, 62 F; chimney gas temperature, 500 F; sea level atmospheric pressure, Bo = 29.92in. Hg; atmospheric and chimney gas density, 0.0863 and 0.09, respectively; coefficient of friction, 0.016; length of friction duct, 200 ft. The chimney discharges 100 lb of gases per second. ., Solution: Substituting these values in Equation 3 and reducing, .. D. = 2.96 X 200 X 29.92 X /0.0863 \ 522 0.09\ 960 / 0.00126 X 100' X 960 X 0.016 X 200 10s X 29.92 X 0.09 = 1.27 - 0.14 = 1.13 in. Fig. 2 shows the variation in the available draft of a typical 200 ft by 10 ft chimney operating under the general conditions 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 AMOUNT OF CASES FLOWING AND DISCHARGED POUNDS P R SEC Fig. 2. Typical Set of Operating Characteristics of a Natural Draft Chimney the amount of gases flowing increases, the available draft decreases until it becomes zero at a gas flow of 297 lb per second, at which point the draft loss, due to friction, is equal to the theoretical intensity. The point of maximum draft and zero capacity is called shut-off draft, or point of im pending delivery, and corresponds to the point of shut-off head of a centrif ugal pump. The point of zero draft and maximum capacity is called the wide open point, and corresponds to the wide open point of a centrifugal pump, a set of operating 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 chimney. This chart is based on an atmospheric temperature of 62 F, a chimney gas temperature of 500 F, a unit chimney gas 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 Equations 2 or 4. DETERMINING INDUSTRIAL CHIMNEY SIZES If the required performance for a proposed chimney is knownj and v _ chimney-gas velocity is assumed, Equation 3 can be transposed to yield the .# necessaryheight, and an equation can be developed for the required diame- ft ' These operations remit in the following equations: iff ter H= ,, /Wo 2.96B,, ^ y D, W.\ _ ?;.mfWoBoV' I'r) TJ) WA A i `"V? (V :% Tr ->v; -ffy "L. ' - v .001 .002 .003 .004 .005 .006 Available Draft pef FI # Height ia of Water . Fig; 3. Chimney Performance Chart To talve a typical example: Proceed horizontally from a Weight Flow Kate point to intersection with diameter line; from this intersection1q\. low vertically to chimney height line; from this intersection follow hori zontally to the right to Available'Draft scale. Starting from a point of Available Draft, take steps in reverse order. . . . D2 Vjrom whjch The weight of gas per second, W = 12.075 ! D = 0.288 \/-T- y BoJVd whieere H = required height of chimney above grate, feet. D = required minimum diameter of chimney, feet. V = chimney gas velocity, feet per second. D, -- total required draft, inches of water. For large chimneys, it is usual to assume that total construction Chimneys and Draft Calculations 417 is least when the product HD (height X diameter) is minimum. . On this assumption, the product of Equations 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: \ fWo / 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 figures for boiler plants are: Average chimney gas temperature 500 F...................................... i\ = 960 F absolute Average atmospheric temperature 62 F........................................ T0 = 522 Fabsolute Average coefficient of friction 0.016.....!!........................ / = 0.016 Average chimney, gas density, 0 F, 1 Atmosphere.................... Wo = 0.09 lb per cu ft Barometer reading, sea level......................... I..............................B,, = 29.92 in. Hg When these values are substituted in Equations 7, 8 and 9, respectively, the results are: H = 190>, (10) D = 1.5W*1* (11) V. = 13.7W1'* (12) These equations should be used for general operating conditions only, or where the required data necessary for an exact determination.are difficult or impossible to secure. Whenever it is possible to obtain accurate data,< or the anticipated operating conditions are fairly well known, the required size should be determined from Equations 7, 8, and 9. Additional construction data for large industrial chimneys, whether brick, concrete, or steel, may be found in Kent's Mechanical Engineers' Handbook4 or the Handbook of Building Construction.5 RESIDENTIAL CHIMNEYS A residential chimney, to provide satisfactory performance, must have adequate height and area, be of, permanently tight construction, be as smooth as practicable internally, and be of such construction as to present no fire hazard to the building. The height of a residence or apartment chimney is usually limited by the height of the building, and by cost. ne chimney height and location that are best suited to a building from an architectural standpoint, will sometimes be unsatisfactory for the proper PPeration of the heating equipment. Chimney height is likely to be critical `n one-story ranch-type or rarribler-type houses, and therefore, it- is im portant to compare carefully the available draft of the chimney and the OQuired draft of the heating appliance to determine whether or not they operate together satisfactorily. . Most residential chimneys are constructed of brick with a clay flue liner, i Vjecently several lightweight, prefabricated chimneys have been mar- met i These chimneys were primarily designed for use with gas equip- p. > out recently several have been approved by the National. Board of ^ ? hfiiderwjters for use with all types of fuels. The advantages of the Slight, prefabricated chimney are ease of installation, somewhat lower . > and reduced weight on the supporting structure. 418 CHAPTER 17 1954 Guide % 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 occur in a residential chimney for very low flue-gas velocities. At present, it is best to rely on actual test data for determining 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 entering 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 Chimneys and Draft Calculations 419 Fig. 6 is a graphical representation of the available draft for a 13-ft brick chimney with a nominal 8 X 8-in. flue liner7 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 con ditions. This method is based on the chimney efficiencies7 shown in Fig. 7 and the ideal draft computed from the chimney inlet temperature. Fig O S IO IS 20 2S 30 35 HEIGHT OF CHIMNEY ABOVE CENTER LIME OF THIMBLE-FEET 4. Available Draft for 9" x 9" and 9" x 13" Masonry Chimneys (Ambient Temperature 0 F) ambient temperature of 60 F. The available drafts produced by 9 X 9-ini 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.6 In tests of these chimneys the smaller chimney produced slightly greater drafts in the lower end 9/ the range of mass flow rates whereas the larger chimney produced slight? higher drafts in the upper end of the range. '_`s The chimney height for heating plants that operate on an on-off or highr fire low-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 temperature decreases are not required to operate at rated input except when outdoor temperatures approach design conditions. For such systems, the chimnef height should be selected from Fig. 4 which shows the available draft an outdoor temperature of 0 F since this is likely to be the more critics1 condition with respect to chimney draft. The available draft for outdoor, temperatures between 0 F and 60 F can be obtained by interpolation fro Figs. 4 and 5 with only slight error. The available draft may be expressed as: where Da = flcDj (13) . ,, ------- ..afaaa * j6. , wis ueaireu conaiuons oi tempera ture and flow. ** ideal draft, calculated from Equation 14, assuming that the barometric pressure is 29.92 in Hg, and the ambient temperature is 60 F. Di = 0.2554B*// (k.-k) where = barometric pressure, inches of mercury, H = chimney height, feet. 2\ = chimney inlet temperature, Fahrenheit degrees, absolute, 7.= ambient air temperature, Fahrenheit degrees, absolute. (14) CHAPTER 17 1954 Guide ,-*; 420 The clay-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 chimneys can be used, with slight error, for chimneys -made of shale tile, concrete block, or cinder block.8 . -.7 SHORT CHIMNEYS 7 The application of heating systems to one-story houses without base-.,j ments requires special consideration because the chimneys in such houses are often made so low in height for architectural reasons that they produce 1 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.: _ gases out of the building since it is undesirable and contrary to American,.. Chimneys and Draft Calculations 421 "b SBqauroarmeeFtrluicePLreinsesurre6?2x9.962$ iinn.. Hings.idAe.ir Temperature 60F. . standards to have the products of combustion discharged in the living space. If a natural-draft oil-burning device is operated with insufficieuV draft because of a short chimney, smoky combustion usually occurs, pulsations are possible in the combustion chamber, the chimney or smokepipe may become blocked with soot, and the capacity of the heating egui^ ment may be reduced to the point of inadequacy. Insufficient draftIs not ordinarily the cause of smoky combustion in coal-burning heaters, but .too short a chimney can cause slow pickup of the fire and insufficient heating capacity of the device. q. Based on the amount of draft usually required for present-day heating systems at rated output, any chimney with an effective height of less 15 ft above the center line of the thimble should be regarded as a shPf1 chimney. In short chimneys every precaution should be taken to attain the highest possible average temperature in the chimney and the lowe?. practicable friction loss. Short chimneys of conventional constructin'1 are likely to produce from 60 to 90 percent of the ideal draft and, therefor the draft would only be increased from 10 to 40 percent if all frictioman cooling could be eliminated. ,7 The available draft lor short chimneys can perhaps be determined iun j readily by using Equation 13, Fig. 8, and Table 1. Fig. 8 shows there j M 422 CHAPTER 17 1954 Guide and the amount of exposure to the outdoor air. Experimental data are'/ not sufficiently complete to tabulate efficiencies that take into account ah ; 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 literature8 7 -8-' and summarized in.Table 1 for use with/ Fig. 8 in determining the available draft produced by short chimneys 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 temper/; ature increases over the applicable range. In part C of Table 1 the effi- m -C J Table 1. Efficiency of Short Chimneys A. Mabonht Chimneys Height A ft Flue Gas Flow Rate lb/br Internal Liner Sire, in. Dia. 7 7 z 11 and -'l Dia. 10 ,* 5 to 15 Efficiency, Percent 90 200 315 75-82 83-84 75-89 65-76 67-85 67--86 65-80 ^ 82-88 <fc j 801--8o9p "^ (Inlet Flue Gas Temp 200 to 1000) '_-' B. Uninsulated Metal Chimneys - Height A ft 4 to 8 Flue Gas Flow Rate lb/hr 90 200 315 C. Metal Chimneys1* Internal Diameter, in. :fp, 8 I' --- Efficiency, Peroent . 99-100 888533---98858 % * 70-880 ^$ I (Inlet FlueGas Temp- 200 to 600:F(1| ---------------- ---------------- r7T2 1-in. insulatioP^ -with 1-in. op?1,- air space aroun^ chimney *6 SInixte-irnncahl cdhiaim. 6n-einy; nfloutergeacsomflomwernadteed50fotroth1e25selbf/lohwr; riantleest. flue gas temp. 200 to 1000 F. ciency values listed will yield the available draft for the range of flows, inlet flue gas temperatures, and chimney height shown within 1 percent. .^ In the application of short chimneys, observance of the following pre cautions will assist in obtaining the highest practicable draft and maycurC unsatisfactory operation of the chimney and heating plant in certain stances: ,.\f 1. Use a minimum length of horizontal smokepipe between the heater ^ 2. cInhsimulnaetey.the smokepipe and the chimney itself, if made of metal. Insulate, of the chimney liner in masonry chimneys reduces the heat loss from tbe Av 3. gDaosens oatnudsteheaninofivletrrastizioend ochf icmonldeyairb.ecause larger chimneys produce grAfci* cooling of the flue gases. ` . ^7 Chimneys and Draft Calculations 423 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 heat ers since most barometric dampers 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 intermittently-fired 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. FLUE CAS FLOW- POUNDS PER HR 200 400 600 eoo 4 6 8 10 12 14 *6 18 C02 -PER CENT Fig. 9. Graphical Evaluation of Rate of Flue Gas Flow from Percent CO* and Fuel Rate* * Average density gas 0.0845 lb per cu ft, 62 F. Average weight oil 7.08 lb per gal, 60 F. 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 question, and comparing it with the performance values of the heating unit (either natural or forced draft type) at the desired output, it is possible to de- ternune whether the chimney is adequate in height for the particular ueating unit it serves. For calculations where the fuel rate and the percentage C02 are the only 'vn factors, the flue-gas rate can easily be determined for coal, oil and cafl frm By entering Fig. 9 at the percentage C02, moving verti- fu | 0 curve for the type of fuel, and then moving horizontally to the fuel irate' flue-gas rate in pounds per hour may be determined for any **of t^e AeseriBed methods of determining available draft may be chin/ ^ a Sraphical solution to the problem may be had for the 8 X 8-in. ^rorn Figs. 6, 7 and 9. This solution can be best explained by a numencai example. 424 CHAPTER 17 1954 Guided Example S: Determine if 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,. ` n. ' Solution: From Fig. 9, a flue-gas rate of approximately 180 lb per hr is obtained. The available draft for a 180 lb per hr. fuel-rate, ana an. inlet temperature of 400 F, obtained from Fig. 6, is 0.056 in, of water. This indicates that the chimney is ade-' quate. : The selection of chimney areas for liquid- and solid-fuel-burning devices is difficult because of the variability in efficiency of different models, the possibility that soot on the lining will restrict the chimney area, and the variation in combustion air requirements of different solid fuels. Figs. 6 and 7 show that a given chimney produces a maximum available 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 effect10 on the combustion rate of a solid-fuel burning device if it were operating to the left of the optimum point in Fig. 6 because an additional increment in mass flow rate would increase the available draft a small amount and tend to increase the mass flow.still more. On the other hand, a chimney operating to the right of the optimum point in Fig. 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 information on the effect of cross-section area on the capacity of masonry chimneys is provided by recent tests8,11 on several chimneys with liners having nominal outside dimensions: 9 in. diameter, 12 in. diameter, 9X9 in-> and 9 X 13 inThese 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 larger 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 data9 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 inlet that produce the maximum available draft for masonry chimneys8 of several conventional sizes and with;an effective height of 15 ft. This table shows that a 9-in. round chimney15 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 a 9 X T3` 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 consideration. : 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 heating plant, the breeching,,and the smokepipe, than in the vertical chimney liner. An increase in-tb liner diameter of one inch above that required for a clean chimney ^ probably make adequate allowance for soot deposits in all but the worst' Chimneys and Draft Calculations .. 425 cases. Where smoky combustion is likely to occur and the mass flow rates on a.clean chimney basis approach those listed in Table d, the next larger commercial size liner should be used. Smoky combustion with oil-burning 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 developed by . the industry and approved by the American Standards Association, in order to effect economies, that can be derived from coordination of the dimensions of building materials. These linings are known as modular clay flue Table 2. Approximate Flue-Gas Flow Rates fob Maximum Available __________________ ________ Draft in Masonrt Chimneys Nominal External Liner Dimensions 9 in. Dia. 9 in. x 9 in. 12 in. Dia. 9 in. x 13 in. Internal Area of Liner,. Sq In | 200 Floe Gas Temperature at Chimney Inlet, Fahb. GOO 1000 200 600 1000 Maas Flow Rate, LB/HR : ' Flue Gas Velocity at Chimney -: Inlet, FPM . 38.5 49 78.5 77 170 215 J?0 295 150 306 Above 320 Above 320 130 334 Above 320 Above 320 175 250 175 i 400 150 150 300 600 linings, and the dimensions and tolerances are summarized in ASA Stand ard A62.4-47. As the effective areas of these liners are somewhat smaller 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.- Typical flue-gas temperatures and drafts required at rated output for several kinds of domestic heating appliances12 are contained in Table 3. Chimney height and chimney area for cast iron boilers are specified in the I = B = R Testing and Rating Code of the Institute of. Boiler and Radiator Manufacturers. Mechanically-fired devices such as oil bumers 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 ln attics or in one-story basementless houses. Automatic oil-burning yace heaters, floor furnaces, and warm air furnaces employing naturaldraft vaporizing burners require a draft of 0.06 to 0.08 in. water for outdoor temperatures of 60 F. Coal-burning heaters and furnaces which attain design rating of 0 F would require about the same draft. For such require- fflents, data from Figure 8 and Table 1 show that an effective chimney height, above chimney inlet, should be a minimum of 8 to 12 ft. Because 426 Chapter 17 1954 Guides temperature drop and friction loss in the flue pipe cannot be calculated?* accurately,7 and the resistance of various chimney connection^ 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 provided. Extreme care should be used in the application of forced draft to avoid producing a pressure in the combustion chambers, because they are not usually de signed to avoid the leakage of toxic gases which might result. Induced draft by means of motor-driven fans or blowers will solve lowdraft problems, but would usually be employed for residential systems only as a last resort. Operation of a blower entails some cost, introduces main tenance requirements, and may be dangerous, in event of power failure unless suitab'e protective devices are used. Induced draft fans designed Table 3. Drafts Required by Typical Residential Heating Devices or Appliances Device Draft, Inches Water 0Stack Tempera Fture Deg 0.06 to 0.08 0.06 0.06b 0.06 0.03" 0.05* or less 0.04b 0.06b 1000 860 900 860 __ 400 900 ft Draft in firebox. ** For chestnut sized anthracite. c 18 in. from heater. to resist effects of high temperature and corrosion are available. Fans not carefully designed or modified to meet these conditions should not be ajy plied to this service. CHIMNEYS FOR GAS HEATING Since a gas-designed appliance must be able to operate at rated input (plus 10 or 15 percent) without chimney connection, and without produc ing carbon monoxide, the only function of the chimney is to remove the products of combustion from the room. The chimney provides draft to overcome the friction in the flue pipe and chimney, but does not draw air into the appliance. 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 basis of heat input of the appliance. The chimney sizes adopted by the American Standards Association and the National Board of Fire un derwriters in 1950 for gas appliances13 are shown in Fig. 10. ' Additional provisions of ASA Standard Z21.30-1950 relating to chimney size are:1 2 3 1. In no ease shall the vent area be less than the area of a 3-in. diameter P'P?' 2. When more than one appliance vents into a flue or vent, the flue or vent area shall be not less than the area of the largest flue or vent connector plus... per cent of the areas of the additional flue or vent connectors. . - 3. An elliptical flue or vent may be used provided its flue gas venting capaci. y is equal to the capacity of the round pipe for which it is substituted. Chimneys and Draft Calculations 427 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 appliances converted to gas burning, except those equipped with power type burners and ex cepting conversion burner installations 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-As sociation and the American Standards Association, and is essential for safe Fig. 10. Capacity in Btu per Hour for Gas Appliance Flues or - . Vents ' operation. It is designed to prevent excessive chimney draft which would lower appliance efficiency, to prevent a blocked flue or a down-draft in the chimney from impairing combustion, to provide a relief opening for the products of combustion during down-draft or blocked flue conditions, and o prevent spillage of the products of combustion to the space surrounding the appliance, if there is a chimney draft equivalent to that provided by a ^-It chimney. As the draft hood is designed without moving parts, the ehef opening is always open, and consequently some air is drawn into the jnmney. This air lowers the gas temperature in the chimney, but it so lowers the dew-point of the gases and tends to prevent condensation. installation of conversion burner equipment in large boilers is ually made in accordance with regulations of the local gas company. a 428 CHAPTER 17 1954 Guide In such installations a definite chimney draft may be required for proper., combustion, and consequently the foregoing reference to the use of draft hoods would not apply. ' The products of complete combustion of gas are water vapor (H/)) and carbon dioxide (C02). In the case of manufactured gas, the presence . of organic sulfur compounds, generally between 3 and 15 grains per hun dred cubic feet, gives rise to minute percentages of sulfur dioxide and sulfur trioxide; The.volume of water vapor in the flue products from natural or coke oven, gas is'about twice the volume of carbon dioxide. It is extremely 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 moisture and lin ings made of non-corrosive materials, are advantageous. The protection of unlined chimneys has been investigated and the results indicate that Fig. 11. Capacity of a Rectangular Flue or a Semi-Elliptical Flub, with Semi-Circular Ends Having Its Minimum Width Equal to the Diameter op a Circular Flue, Compared with the Capacity of the Circular Flue after the loose material has been removed, spraying with a water emulsion of asphalt chromate will provide excellent protection. Advice regarding recommended practice and materials for flue connec tions and chimney linings can usually be obtained from the local gas com pany, and should be given careful consideration. RECOMMENDATIONS OF THE NATIONAL BOARD OF FIRE UNDERWRITERS For general data on the construction of chimneys, reference should^ made to the National Building Code, recommended by the National Bom of Fire Underwriters, Article X, Section 1001 to 1006, in which the following are some of the important provisions listed in the 1951 edition: '"r"; 1. Flue Connections Required. Every heating apparatus or heat producing pliance requiring a flue connection shall be connected with a flue conforming to provisions of this article. This shall not include electric appliances; gas appliances, except as specifically required in this article; or oil fired appliances especially: signed for use without flue connection. ' 2. Use of Nonconforming Flues. Flues not conforming to the requirements;?! this article for chimneys, metal smokestacks or vents for gas appliances, shall, n Chimneys and Draft Calculations 429 be used unless listed by Underwriters' Laboratories, Inc., installed in full compliance with the listing and the manufacturer's instructions, and approved 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 noncombustible materials whenever their use is discontinued temporarily, and completely closing them with masonry when discontinued permanently. . 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 con nected. c. The smoke pipe of a heating appliance shall not be connected 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 structure shall be con structed 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 thickness, 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 thickness. In every case the corbeling shall not exceed 1 in. projection for each course of brick projected. e- N change in the size or shape of a chimney, where the chimney passes through the roof, shall be made within a distance of 6 in. above or below the roof joists or rafters. ; ' 5. Chimneys for Heating Appliances, Low Heat Industrial Appliances and Portable l ype 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 re quirements, the thickness of the chimney shall be not less than 4 in. In other build ings the thickness 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 linug conforming to the requirements below. , C`,R!ue 6nings shall be made of fire clay or other refractory clay which will with- tand the action of flue gases and resist, without softening or cracking, the tempera nces to which they will be subjected, but not less than 2000 F. Flue linings may be cast iron of approved quality, form and construction. fli,'*' Re3uVred pluy flue linings sljdl be not less than f in. thick for the smaller ues, and shall increase in thickness for the larger flues. e: Rlue linings shall be installed ahead of the construction of the chimney as it is wit!?6 i Ui1' carefully bedded one on the other in Type A, Type B, or fire clay mortar in close fitting joints left smooth on the inside. the RiQe linings shall start from a point not less than 8 in. below the intake, or, in verr ^n0 "replnces, from the throat of the fireplace: They shall extend, as nearly Icady as possible, for the entire height of the chimney, and be extended 4 in. 00ve the top of cap of the chimney. . frani ^l<;anouts for flues or fireplaces shall be equipped with cast-iron doors and h 6S arran^ecl rematn tightly closed when not in use. flue sh^n^I1 *'w0 or more Aues are contained in the same chimney, at least every third snail be separated by masonry at least 4 in. thick bonded into the masonry wall 430 Chapter 17 1954 Guide fej Iw of the chimney. Where flue linings are not so separated, the joints of adjacent flue '{" linings shall be staggered at least 7 in. < 6. Sizes of Flues. - a. The cross-sectional area of smoke flues shall be designed and proportioned to meet the conditions of temperature, within and without flue, thickness 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 converted readily to the use of solid or liquid fuel, and also for all boilers and furnaces, except those having a flue-gas temperature 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. Approved Type B vent piping is noncombustible, corrosion-resistant 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 of Gas Appliances Only. 1 2. Type B gas vents shall be installed with a clearance to combustible material or construction, whether plastered or unplastered, of not less 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 vent 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 Producing ' Appliances, Heating, Ventilating, Air Conditioning, Blower and Exhaust Systems. 2. Every flue-connected appliance, except an incinerator, unless 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 attached to the flue collar of the appliance as conditions permit, and in a position for which it is designed with reference to horizontal 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 con struction. 3. No vent pipe from a gas appliance shall be interconnected with any other vent pipe, smoke pipe, or flue, unless such gas appliance is equipped with an automatic device to prevent the escape of unburned 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 petro leum 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 chimneys16 made of a variety of materials have developed additional recommendations regarding the construction of masonry chimneys that will decrease the hazard to surrounding combust^ ble materials. '^ GENERAL CONSIDERATIONS FOR CHIMNEYS The draft of domestic chimneys may be subject to a variety of influences -. not usually encountered in power chimneys16 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. Hp.Wji; ever, surrounding 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; - Chimneys and Draft Calculations 431 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 chim ney 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 occurring at the thimble. The effect of recircula tion 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 located in the basement. In the majority of cases, the furnace room has windows and doors opening to the outside on two or more sides of the house. Through these enough air leaks into the furnace room to sustain combustion. In some cases, how ever, windows and doors are so tight as to restrict the flow of combustion air, and thereby affect the correct operation of the chimney. In case the boiler room is fairly tight and is open to the outside on only one side of the house, then 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, Inirif 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 smoke- pipe should therefore, be provided between the utility closet and the living space or the outdoors. If the utility closet is connected to the outdoors, greater difficulty with wind pressures will be encountered. Where a draft regulator is used it should have ample communication with the same 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 inside 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 together. 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. Batteries 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 boilers, and not connected in manifold with an other chimney, in order to avoid the difficulty described previously. In domestic installations it is sometimes necessary to serve a space heater ?r cooking stove and a water heater with the same chimney flue. This j? 1101 desirable, especially for low chimneys, since doors left open on one device, while it is unfired, will tend to annul the draft on another device, '-'as 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 ach fuel-burning device could be served by a separate opening. If two e''ices must be served by one flue-opening in a chimney, their connections 432 Chapter 17 1954 Guide to the chimney should not be located opposite each other. : The con nection from the larger device should be reasonably low, and that from the smaller, up near the ceiling, so that each device can be serviced as well as posable, regardless of the treatment of the other. ,. : Even where such precautions are taken, there is, under unusual condi tions, 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.7 Under certain- similar quiescent conditions, accidental discharge of combustible gases from a defective device into a chimney could result in flow of these gases counter current into the combus tion chamber of another device attached to the same chimney. If ignition occurred in this second device, an explosion could result. : Excessive height in- a chimney does no harm, but means for controlling the draft are more than ordinarily essential if the chimney is too tall. Goal-burning devices often have air leaks around the firebox, arid the draft doors sometimes fit so poorly that the fire cannot be controlled at a low rate. The simplest 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 fireplace is effectively sealed. REFERENCES ' 1 A Study of Flow Phenomena iu the Wake of Smokestacks, by R.H. Sherlock and' B. A. Stalker (Department of Engineering Research, University of Michigan, Bulletin No. 29, 1941). .} * Notes on Power Plant Design, by E. F. Miller and James Holt (Massachusetts Institute of Technology, 1930). - " '' : ' i!<; .* Friction Factors for Pipe Flow, by L. F. Moody (A.S.M.E: Transactions, Vol 66,1I9M4e4,chpa. n6i7c1a)l.E.ngineers' Handbook, Eleventh Edition, by R. T. Kent, E, di.tor in Chies Hf (aJnodhbnooWkiolefyBaunildinSgonCso, nInsctr.u)c. tion, by G. A. Hool and N. C. Johnson (McGrow1 Hille BOobosekrvCeod.,PInecrf.o,rNmeawncYeoorfk,So19m2e9)E. xperimental Chimneys, by R.; S. Dill, P. R-. Achenbach and J. T. Duck (A.S.H.V.E. Transactions, Vol. 48,1942, p. 351). . ,?,! 7 Performance of Residential Chimneys, by L. B. Schmitt and R. B. Engdaiu (A.S.H.V.E. Transactions, Vol. 55, 1949, p. 241). -' 8 Performance of Fourteen Masonry Chimneys Under Steady State Conditions, by P. R. Achenbach and S. D. Cole (A.S.H.V.E. Transactions, Vol. 55, 1949,,,p. 129)8. A Theor`etical and Experimental Investigation o f the Performance ofSome. Short Flues Under Steady-State Conditions, by Robert.D. Tbulman and William'S! Shenkle (Thesis at Massachusetts Institute of Technology, June 1951). . 10 Physics of Chimneys; by P. R. Achenbach (Physics Today, Vol. 2, No. 12, Dec. 194II9)P. erformance of Masonry Chimneys for Houses, by Robert K. Tbulman (H.o.u.s ing18aNndatHioonmael FBinuarenacue Aogf eSntcayn,dTaerdcshnCicoaml PmaeprecriaNl oS.taISnd, aArudsg:. 1C9S4190).1-43 Oil-Burning Space Heaters Equipped With Vaporizing Pot-Type Burners, CS75-42 Automatic Mechanical Oil Burners Designed for Domestic Installations, CS(E)104-43 Warm.Air Furnaces Equipped With Vaporizing Pot-Type Burners; CS109-.44 Solid-Fuel Burn ing Forced Air Furnaces, GS113-44 Oil-Burning Floor Furnaces Equipped Wdft Va1p3oArimzienrgicPanot-STtyapnedaBrdurInnesrtsa.llation of Gas Piping and Gas Appliances in Buliiltd ings (American Stoioiarifs Assoeia&'on, Z21.30-1950). l"t CFiorme fHorat zHaerdatTinegs,ts19w38it,hp.M7a1so(AnrmyeCrihcaimnnGeayss,AbsysoNcioaltaionn)D. . Mitchell (Natiorjei. Fir1e8 CPhroimtencetiyosn aAnsdsDocriaatfito(nChQaupatretre3rl2y,inOcWt.in1t9e4r9A). ir Conditioning, by S. Konzo, petlished by National Warm Air Heating and Air Conditioning Association, 1939)-- *TM' ' CHAPTER 18 ESTIMATING FUEL CONSUMPTION FOR SPACE HEATING Bases of Fuel Estimates; Season Efficiency; Calculated Heat Loss Method: Compu tation and Application, Examples and Solutions, Short Methods for Estimating Heat Loss; Degree-Day Method: Computation and Application, Unit Fuel , Consumption per Degree-Day, Estimating Consumption for Various Fuels, Examples and Solutions, Degree-Day as an Operating Unit; Industrial Degree-Days; Maximum Demand and Load Factors IT IS often necessary to estimate the anticipated heat requirements and fuel consumptions of heating plants for either short or long terms of oper ation. There are various general methods for estimating these condi tions, and frequently the methods can be so modified as even to become usefrilin evaluating the effectiveness of heat production or fuel utilization during plant operation: In applying a consumption-estimating, method to a particular building, it is well to note that the bases of the methods may vary as to reliability. For example: 1. Records of past heat requirements or fuel consumption of the particular build ing are a better basis for estimates than are averages from records of similar buildings. 2. In the absence of paBt records for a particular building, the data from similar plants in the same locality may become very helpful. 3. Averages of consumption taken from many types of plants in many types of buildings in various localities can only produce an average estimate which :may prove to be very inaccurate as applied to the particular building being considered. 4. Estimates based upon computed beat losses (without benefit of operating data) are wholly dependent, of course, on the degree to which the computation represents the actual facts. Where unusual operating conditions exist due to factors such as ex cessive ventilation, abnormal inside temperatures and heat gains from external sources, or where, in the case of proposed buildings of unusual design, no information is available regarding former consumption, it is necessary to estimate fuel consumption from the computed heat losses. In. preparing fuel consumption estimates it i3 well to realize that any estimating method used will produce a more reliable result over a long Period operation than over a short period. Nearly all of the inethods in cominon use will give trustworthy results over a full annual heating season, *md in some cases such estimates will prove consistent within themselves for monthly periods. As the period of the estimate is shortened, there is ore chance that some factor not allowed for in the estimating method become dominant, and thus give discrepant and even ridiculous results.. . The Calculated Heat-Loss Method, and the Degree-Day Method of estimating fuel requirements are illustrative of all methods used. Both ?rethods are based upon an estimate of seasonal efficiency. The former ls a*so based upon an estimate of average seasonal temperature. Neither Piethod takes into account factors which are difficult to evaluate, such as 433 i 1. 1 ! Hit 434 CHAPTER 18 . 1954 Guide opening of windows, abnormal heating of the building, poor design of heat ing system, sun effect, and other variations. The Degree-Day Method is the more practical since it is based, in part, on actual consumption data. The presentation of the two illustrative estimating methods will be pre ceded by a discussion of seasonal efficiency. SEASONAL EFFICIENCY The seasonal efficiency differs from the measured efficiency of the fuel- fired heating unit because it is affected by the many minor sources of extraneous heat gain and heat loss. Throughout a season, useful heat is supplied to a building not only by the heating unit, but also by the external surfaces of the heating unit, the flue pipe, and the chimney. In addition, heat is gained from lights, occupants, cooking and other appliances, and from the sun. Indeterminable amounts of heat are lost through radiation directly to basement or utility-room walls and floors, from the heating unit, the distribution system, and the flue pipe, from stand-by operation of the unit, from opening of doors and windows, and from faulty adjust ment and operation of the combustion unit. Fortunately, data which are available permit the making of reasonable estimates of seasonal efficiency for residences. The average fuel consumption of various types of approved gas-fired equipment has been obtained from a large number of heating systems.1 Corresponding seasonal efficiencies 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.2 Other tests on coal-fired room heaters indicate sea sonal efficiencies of 65 to 75 percent, when the heat from the flue pipe was included.3 A survey of 30 residences in one locality showed a variation of 45 to 75 percent in utilization efficiency, depending upon the condition of the equipment and the fuel used.4 A summary5' 6 of many tests in two research residences at the University of Illinois, using many fuels and systems, gave values of 67 to 90 percent for overall house efficiency (the ratio of the heat loss from the structure to the heat input to the unit for an average test day). These data were used by the Small Homes Council7 of the University of Illinois in a tabulation of the comparative costs of heating the same build: ing with various fuels. i The approximate seasonal efficiencies shown in Table 1 are suggested as a guide. : Table 1. Approximate Seasonal Efficiency Type of Fuel-Burning Unit Approximate Sea sonal Efficiency, Percent Type of Fuel-Burning Unit Approximate Sj4, SONAE Ei-PICIOCT. Percent Gas, designed unit..................... Gas, conversion unit.................. Oil, designed unit....................... Oil, conversion unit.................... Bituminous coal, hand fired with controls............................ Bituminous coal, hand fired without controls...................... Bituminous coal, stoker-fired... 75-80 60-80 65-80 60-80 50-65 40-60 50-70 Anthracite, hand-fired with controls.................................... Anthracite, hand-fired without controls............................ Anthracite, stoker-fired.-......... Coke, hand-fired with con trols.......................................... Coke, hand-fired without con- trols.................... _................... Direct electric heating............. W-SO 50-65 60-80 60-80 ':'r Estimating Fuel Consumption for Space Heating 435 CALCULATED HEAT LOSS METHOD - In the Calculated Heat-Loss Method a constant average outdoor temper ature is assumed throughout the heating season. ' This average tempera ture is considerably above the design temperature given in Chapter . 12. The method becomes unreliable whenever data on the seasonal average temperature are not available for the particular locality. . If the length of time is shown over which the degree-day data apply; in the particular' locality, it is possible to calculate the average temperature from the defini tion of the degree-day (see Chapter 1). When this is dofie, the two meth ods described in this chapter become identical. The average temperature for the period October to April inclusive, is listed in Table 1, Chapter 12, for U. S. and Canadian cities. Computation and Application ' In order to apply the Calculated Heat-Loss Method, the hourly heat loss from the building under maximum load, or design condition, is com puted following the principles discussed in Chapters 9, 11, and 12. The fuel requirement is then computed by the equation . '' where H(t - ON E(ld - t0)C (1) F = quantity of fuel or energy required (in the units in which C is expressed). H = calculated heat loss including infiltration loss, Btu per hour, during the design hour, based on t0 and td. t = average inside temperature maintained during beating period, Fahrenheit. t, -- average outside temperature through estimate period, Fahrenheit (for cities with an Oct. 1-May 1 heating season--see Table 1, Chapter 12). fa = inside design temperature, Fahrenheit (usually 70 F). to = outside design temperature, Fahrenheit (see Table 1 in Chapter 12). N = number of heating hours in estimate period (for an Oct. 1-May 1 heating season, 212 days X 24 hr = 5088). E = efficiency of utilization of the fuel over the period, expressed as a decimal; not the efficiency at peak or rated load condition, c -- heating value of one unit of fuel or energy. Although the assumption of an Oct. 1-May 1 heating season is reason ably accurate in the well-populated New York-Chicago zone, it is not valid as far north as Minneapolis nor farther south than Washington, D. C. and St. Louis. Consequently, it is suggested that allowance be made for this variation, especially in the far north or southern cities. /: A residence building is to be heated to 70 F from 6 a.m. to 10 p.m. ana 65 p from 10 p.m. to 6 a.m. The calculated hourly heat loss is 120,000 Btu per our based on 70 F inside at --10 F outside. If the building is to be heated by metered eam, 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 oufS P,urckased steam, the efficiency can be assumed as 100 percent. Assume average iside temperature as 36.4 F. The average inside temperature is: (16 X 70) + (8 X 65) 24 68.3 F. 436 CHAPTER 18 . 1954 Guide Substituting in Equation 1 p = msmmz-awsm = lb 1.00170 - (-10)]1000 Example 2: What would be the fuel cost to heat the building in Example t during an average heating season, using stoker-fired bituminous coal at $14.00 per ton having a calorific value of 13,000 Btu per lb, assuming that the seasonal efficiency of the system is 65 percent? Solution: Substituting in Equation 1 : 120,000 (68,3 - 36.4? 5088 28,800 lb. 0.65170 - (--10))13,000 The fuel cost is then (28,800 2000) (14) = 201.00 Example S: What will be the estimated fuel cost per year of heating a building with gas, assuming that the calculated hourly heat loss is 92,000 Btu based on 0 P;; which includes 26,000 Btu for infiltration? The design temperatures are 0 F and 72 F. The normal heating season is 210 days, and the average outside temperature during the heating season is 36.4 F. The seasonal efficiency will be 80 percent. The'; heating plant Will be thermostatically controlled, and a temperature of 65 F will be' maintained from II p.m. to 7 a.m. Assume that the price of gas is 7.5 cents per 100,000 Btu of fuel consumption, and disregard the loss of heat through open windows and dooSrso.lution: The average hourly temperature is t, (72 X 16) + (65 X 8) ~24 69.7 F. The maximum hourly heat loss will be H = 92,000 Btu. The seasonal.heat loss is _ 92,000 (69.7 - 36.4) X 24 X 210 = 2697 hundred thousand Btu. ~ 100,OCX) X 0.80 X (72 - 0) The estimated seasonal fuel cost will be . 2697 X $0,075 = $202.00 It should be noted that savings from night setback may not result as calculated.' Room temperature may not decrease and combustion efficiency may be poor during morning pickup. See Reference 8. 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 developed9 which makes post, sible a quick solution if the gross wall, ceiling, or floor areas and respective > 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 transmission coefficients. The formula was developed1 to apply to detached houses approximately rectangular in shape with total* exterior door and window areas equal to about 25 percent of the floor arej " and with a floor area not greater than about 1500 sq ft. Equation 2 is-foc a one-story residence, and Equation 3 is intended for two-story structures;. Hi = A{0 + U, + U.+ V,) (U - U 'Ik H, = A (G + 1.2 U. + 051/c + 0.5 U,) (U - t.) Estimating Fuel Consumption for Space Heating 437 where Hi = heat loss from one-story residence, Btu per hour. ' H, = heat loss from two-story 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; (1) all the area oh each principal floor level; (2) the area of all finished habitable attic rooms, including bath rooms, toilet compartments, closets, and halls; (3) all other areas intended to be heated and not located in the basement. G = glass and infiltration factor for ordinary construction: (0.45 for no weather stripping or storm windows), (0.40 for weatherstripping), (0.30 for storm windows with or without weatherstripping). ' : .. (/,, = coefficient of transmission for outside wall. . V< = coefficient of transmission for ceiling. Ut = coefficient of transmission for floor, . td = inside design temperature, Fahrenheit degrees, to -- outside design temperature, Fahrenheit degrees. , . Notes for application of Equations 2 and S. .,. 1. The calculation of heat loss from heated spaces into adjacent spaces such as attics, bftsementless areas, and heated or unheated garages shall be based on the assumption that the temperature of such adjacent spaces is the same as the outside design temperature. . , 2. For all floors over basements or other warmed spaces assume Vi = 0. 3. For structures having concrete slab'floors laid on the ground a modified appli cation of the formula may be made. Assume Ui -- 0 and calculate the heat Iosb 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 BMS Report 103. 4. No basement area is to be included in the formula calculation. 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. Both the graphical method9 and FHA formulas, when used within the limitations established, have been found to give reasonably accurate results for the average residence, but if precise estimates are. required, the procedure outlined in Chapter 12 should be used. . In the case of gravity warm air heating installations, the load was for merly expressed in square inches of leader pipe 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. DEGREE-DAY METHOD This method is based on consumption data which have been taken from buildings in operation, and the results have been computed on a degree-day basis. While this method may not be as theoretically correct as the Cal culated Heat Loss Method, it is considered by many to be of more value for. practical use. The amount of heat required in a building depends upon the outdoor temperature, if other variables are eliminated. Theoretically it is pro portional to the difference between the outdoor and indoor temperatures. Y"e American Gas Association10 determined from records in the heating of residences that the gas consumption varied directly as the degree-days, J,as the difference between 65 F and the mean outside temperature. In other words, on a day when the mean temperature was 20 deg below 65 F, WlCe as much gas was consumed as on a day when the temperature was 10 5... 438 CHAPTER 18 1954 Guide deg below 65 F. For any one day, when the mean temperature is less than 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. De;gree-days may be calculated on other than the 65 F base for use mainiy for warehouse and other industrial spaces in which temperatures to be maintained are considerably below the 68 to 72 F range. They are listed in a later section of this chapter. Studies made by the Notional District Heating Association11 of the metered steam consumption of 163 buildings located in 22 different cities and served with steam from a district heating company, substantiate the approximate correctness of the 65 F base chosen by the gas industry. Table 2 lists the average number of degree-days which 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 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 dividing 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 tem perature normals on record for the various stations. Any attempt to apply the degree-day method of estimating fuel con sumption for less than one month would be of very little value. It should be noted that this method of calculation is based on a long term average and cannot be expected to coincide with any single year in calculating fuel requirement. Individual yearly degree-day calculations may vary as much as 20 percent above and below the long term average. ' If the degree-days occurring each day are totaled for a reasonably long period, the fuel consumption during that period as compared with another period will be in direct proportion to the number of degree-days in the two periods. Consequently, for a given installation, the fuel consumption can be calculated in terms of fuel used per degree-day for any sufficiently long period, and compared with similar ratios for other periods to determine the relative operating efficiencies with the outside temperature variable eliminated. Computation and Application The general equation for calculating the probable fuel consumption bjr the degree-day method is: . F=VXNxDxC, (*) where F -- fuel consumption for the estimate period. ' U = unit fuel consumption, or quantity of fuel used per (degree-day) (ftW*ni* load unit). , N -- number of building 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. Ci -- temperature-correction factor from Table 3. , ' Values of N depend on the particular building for which the estimate is Estimating Fuel Consumption for Space Heating 439 Statzon Ala.. Anniston........... . 05/08-40/41 Birmingham... .A'98/99-45/46 Mobile................... |98/fl-45/46 Montgomery........ 98/99-45/46 Flagstaff............... 98/90-10/41 ................. [98/09-45/46 Yum"........... `.198/99-40/11 fc' 63 J CO > Z B Q *-<9 * < B z <S -- ----- ------ >< !S`:n 7n 0 n>, 135 388 800 609 152 tl -`ii! J48! 588 Ml) 497j 313 j 203! 377i 3971 314; 176 130 52 >,} ,1* ?79 184 *94 405 339 2tnl 847 UU U67 970 889 66l! 0, 18 168; 384! 402 263j 164J 47 37 J 23 1 3, o! 10 0; 469 190 2806 2611 1566 2071 7241 1441 Ark... Bentonville......... 08/07-40/41 Fort Smith........A!98/9S-lS/4a Calif... Lmle Rock....... A'98/99-15/48 1""*"................... 98/99-45/46 Fresno--...........A 98/99-45/46 Independence... |9S/99-40/41 Los Angeles...... 98/99-15/16 N*Ug...............17/18-38/39 38/39-40/4lj ? 9 I13l 306' 318 182! 85 22 1 38 216; 516 810 879! 716' 5]Q 247 07 o0.' I1t1 120. 383 H 344 fJ6i61t87'' 770643 Ml. 6671Q5, 478 390 gj 154 145 - 11 o' ! a?J' ??9 5S2i 573! 380 f 2li, e,2i 778 799/ 619 5 " no, 2251 272! 235 19 2211771i 4411A6 a44j7V;. 2o4j3o,1' 317 425 467, 406, 289 477 212 1im2s4 437 440; 391 307 152: 52! 267 120 is} 158 103 27 26; 0 4J3 415 363 1036 4036 3226 3009 4758 2403 3834 1391 1495 4474 I44/45-45/46 Sacramento.......... 198/99-45/46 San Diego.......A 98/99-45/46 ban Francisoo.... 98/99-45/46 Colo... ??n Jose......... . 08/07-40/41 Denver................. 98/99-45/46 Durango.............. 04/05-40(4\ Grand Junction. .' 98/99-45/46! Lea^Ville............. -107/08-40/41 Conn. g-uWo-:.......... -A.;98/99--45/46 ..........A,04/05-45/46 345 59j! 6011 419' 328 230 ?l 332 582 595 405 326' 143 2521 300' 257 230 24l! 420 460 340 317 329 512 5271 383 ' 339 716 1005 1023 897 790 37i MJI 535 86l!l204:i271 1002 859 332* 509 M -f .S'SSffigglg.^g* 249. 167 516.* 275 615 394 377 152 990 740 446 195 434! 29 J 2653 2680 1596 3137 2823 5839 7143 5813 10678 5558 D. C.. Fla. Apalachicola Jacksonville. Ga.. F?,m*f..................A98/99-45/46: 48 ............... 98/99-45/16. 48 Idaho.. III.. ,................A 98/99-45/46 48 ........... (00/01-32/33' 33 48 Ind... Iowa . Kan... Ky.. fort Wayne. ;;111^/461 i Indianapolis..... (98/99-45/46 48 T?TMSenter- I8/l~31/32 14 rCtharl\es City........ 0142//0153--4455//4486 Davenport........... 98/99-45/46 nfh?IQeS........... 93/99-45/46 S"b.uSue........ V.. 98/99-45/46 Sfktik:.............. 98/99-41/42 Sioux City........ A 98/99-45/46 prdc"y::.A;d 34 42 48 48 48 44 48 48 48 38 48 I*... Me... ............ 98/99-40/41 RShhrevOerpleoartn..s............A. 9988//9999--4455//4466 import........... 98/5m5/<$ Greenville........... .'07/6M0/41 158, 394 244 524 213 42 ! Kfl12J7i1109 1023 849 522 221 4?l 231 353 872 928 834 624 340 101 o' 95 ft S 323 Mi, 159 38 0n0i 2^( 0 V2; 14 ; 21 15 131 7 42 0| 0 15 411 53 45I 9a 3 O0[f O0 ' T6, m60 1P49j 313527 215256 62 3119 S'?{ 128: 392 644 660 563 382 169 J 5? 21? 329;. 533 448 274 107 S1 J'n f SJ S ?32 338 449 278 108! >?! 17; 9. 21 ,.? 136 107 , 176 .22If'205822 363190' 333995 293932 117948 385 717 1025 1077; 840 688 378 688 932 992 779 603 475 821 1159 1224 1004 845 52i 440 .371 550 '252! 193 330 7 7 52 iff f? 337' 22 222 193 *23, 878 748 512 712 1116 1218 logo g6I 730 *126 1231 1035 790 232 531 436 60 259 178: J3 4 S. 9? El 7*? % 374 737 H07 1211 1052 864 66 297j- 660 1032 1102 973 737 23S778! 18352 504' 2t7l 410 154 139 24 J 62 ,91 270 672470i 1919034 11027329 899776 43: 906 1362.1535 1281 344! 748 1176.1291 1111, 688670 995 835 502 358 552 448 245 133 255 171: 19 !2 % 767 1204.13201132 843 446 171 1'*32 3, 17218, 68, 3SV0?3}l 6!*2*8?0 11m027479\(1,\31Z981a iI1f>1S29S0 288, 670 !060|lU4i 954 ?Sr15i 712 493 397 485 365 204 136 202 142 J9i J23! 641! 998|1045 Hl 679 930 *025 868; 668 817| 599 3511 282! 139 98' 5? 2S4| 623 1013.1096. 9171 659 326; 116: StvS S5 ?Ht S6*IS|' ?884171091316l 8136 658084 290, 298. 103 93' 47 6113 : 47 5880 14} 0| 001 o! oj 01 4561 1252 1185 59 185 1281 571 21 2985 2306 oI| 1. 2338 1635 1513 92 5678 52 5109 124 6741 4 3957 671 6282 28 16 6004 5446 4410 422ll1 6232 5458 54' 6239 15 5117 62 7624 29: 6252 29. 6375 18 5663 40 is; 6905 5425 20 5069 4616 5075 4644 4417 352, 123 4792 146.' 27lj5281 ^7|,K4|lt64i 1238 1080 31 1 79j 10, 1203 2132 778j 630^ 301 8445 ........asI/M Baltimore......... os; n 0/ '!! 3`6 .*2 464 1625 1443 1251 4?l 'H 794 1182 1309 **88 997 1j S3t 227| 526 S55 921, 837, 637 842, 466 671 376 343 95 194 136; 12> 9439 7377 4487 i over a varied 440 CHAPTER 1io8 1954 Guide Avebage Monthly and Yearly Degbee-Days fob Cities Table 2. United States and Canada*- b (Continued) State Boston...............A 98/9^-45/46 Fitchburg....... ... 08/99--40/411 Mich. Nantucket........... Alpena....... :: Detroit.............. A|.,9988//9999--4455//4466 Bscanaba........ 98/99-45/46 Grand Rapids 03/04-45/46 .Houghton....... ,00/01-40/41 42/43-45/46 Lansing----- 10/11-45/46 Ludington. ,12/13-40/41 Marquette....... . 98/99-45/46 SaultSte. Marie.A| 98/99-45/46 Duluth.............. 98/99-45/46 Minneapolis-- 98/99-45/46 Morehesd......... 98/99-40/41 St. Paul............ 98/99-32/33 37/38-40/41 Miss.. Corinth.... Meridian... 09/10-40/41 00/01-45/46 Vicksburg.. 98/99-45/46 Mo..... Columbia.. Hannibal.. 98/99-45/46 98/99-40/41 Kansas City--A ,98/99-45/46 Saint Louis......... | 98/99-45/46 Springfield... iAi 98/99-45/46 Billings.......... - -A| 09/10-45/46 . Havre........ 198/99-45/46 Helena........... . .A|198/99-45/46 Kalispell.. . 99/00-45/46 Miles City......... A],98/99-45/46 Missoula........ 92/93-45/46 Drexel........... 15/16-25/26 Lincoln .*.... North Platte.. 98/99-45/46 ,198/99-45/46 Omaha.......... , A 98/99-45/46 Valentine......... ,98/99-45/46 Reno.................. Al 05/06-45/46 - Tonopah___ _ -- 14/15-40/41 Winnemucca....... 98/99-45/46 N. H. N. J.. Concord............. A] 03/04-45/46 Atlantio City... (98/99-45/46 Cape May............ ! Newark..............A 98/99-31/32 98/99-23/24 ,35/36-40/41 N. M. N.Y. N. C. N. D. Sandy Hook 25/16-40/41 Trenton....... 14/15-45/46 Albuquerque.. .A| 19/20-45/46 Roswell.... ,05/06-45/46 Santa Fe... 98/99-45/46 Albany...... 98/99-45/46 Binghamton......... . 98/99-45/46 .Buffalo................A|198/99-45/46 Canton-- 06/07-45/46 Ithaca....... New York. 99/00-42/43 98/99-45/46 Oswego-- 198/99-45/46 Rochester.......... A 98/99-45/46 Syracuse............ Aj 03/04-45/46 Asheville....... ,02/03-45/46 Charlotte.... Hatteraa........ 98/99-45/46 98/99-45/46 Manteo.......... 04/05-28/29 Raleigh......... 198/99-45/46 Wilmington. 198/99-45/46 Bismarck.... 98/99-45/46 Devils Cake. 04/05-45/46 Grand Porks 12/13-40/41 42/43-45/46 43 44 48 48 25 48 48 48 42 33 Williston..;....... Cincinnati........ Cleveland......... Columbus........ Dayton............. 98/99-45/48 ,98/99-45/46 98/99-45/46 98/99-45/46 11/12-42/43 45/46 48 Okla. Ore.. Sandusky......... 98/99-45/46i Toledo............... 98/99-45/46 Broken Arrow.. 16/19-30/31 Oklahoma City. 98/99-45/461 Baker................ , 98/99-45/46^ Medford....... :,. ,A| 11/12-40/41 45/46 Table 2. Average Monthly and Yearly Degree-Days for Cities in the United States and Canada** b (Continued) 0'(0a 5a fc * "gS o 0 < sHi GQ Ore.... Portland. Roseburg Erie....................... 98/99-45/46, 98/99-45/461 98/99-45/46 S. C.. S. D... PCDGHPCBNPSPRHirhuorluecaiheooaetaerlrrrtiavucearlsrrorairdaelkmWndnbeindigs.evtnus.I-boeea.bsin-gt.lr-oni.sllnulcga-.pe.a.n.-.tser.....hhn..eg...i...dat....t.......P'.....i.eA..Ar.,[[j.,2019990999991917884888088882/////////////21/999099090991289999599991934--44-4--4443444154405551555557/55//4/////4//4///4/3444414464416266668661666 Tenn. Texas ,42/4345/46, Rapid City Chattanooga-. Kn0Jtnlle........... A MentplTM....... " Naabadle 198/99-45/46 98/9945/46 98/9945/46 [98/9945/46 ,98/9945/46 ffiSfcv.-.'.v.'.* 98/9945/46 47 48 48 48 48 48 48 198/99-45/46 SSaviiic::; a 26/2745/46 08/0945/46 2408 38 Utah. Dallaf;......... A 98/9945/46 13/1445/46 Del Rio..........-' El Paso... A T 05/0645/46 98/99-45/461 Fort Worth.---A Galveston.. Houston........ [98/9945/46 98/99-45/46 09/10-45/46 Palestine. point Arthur San Autorno--A 98/9945/46, ,17/1845/46 98/9945/46 Taylor.................... 01/02-40/41 '00/0145/46 48 33 41 48 48 48 37 48 29 48 40 46 Vt.... -' 98/9945/46 48 06/0745/46[ 40. Va.. Wash. w. Va. Wia. 9S/9942/43 Capo Henry-Lynchburg- - ^ [98/9945/46| 98/9945/46 Norfolk. Richmond. Wythevdle.. 198/99-45/461 ,98/9945/46 02/0340/41 North Head !02/0345/46 Seattle.......... [98/99-45/46 Spokane.............. A Tacoma v" Tatoosb Wand. - Walla Walla-- Yakima................. [98/9945/46 98/9945/46 98/9945/46; 98/9945/46 [09/1045/46 Elkins......... * Parkersburg........ Green Bay . La Crosse. Madison- Milwaukee Wausau.......... * Cheyenne.......... Lander......... v Yellowstone Par* ,98/9945/46 98/9945/461 98/9940/411 98/9945/46 [04/0545/46 ,98/9945/46] ,15/1540/41 98/9945/46 [98/9945/46, 104/0540/41 45 48 48 48 48 39 44 48 48 48 48 48 37 48 48 48 48 .42 48 26 48 48 37 : ; 27 28 106 23 . 26 116 8 1 7 101 1 - 5 67 - ) 2 36 3 7 69 > 69 . > 24> 117 1<1 1 79 2( 121 f It 101 1 CC6 C9 0 1 13 10 20 159 725| 775 616 533; 714 730 5821 530] 1049 1159 1105, 922 990, 1073 973 757 884 962 881 685] 9821 1042 9641 751 957 1038 929 736 10741 1162 1071 862 919j 1030 984 876 1012 |1113| 1074 916 1020, 11061 1027 847 428 452> 384 239 560] 568, 482 305 594 651 491 411 650, 6841 551 4031 1409 1572 1353 1039] 108| 4353 H68I 4332 6363 231 5412 ' 17 4739 29 5430 23| 5232 5H 6218 108 5897 113 6397 600 21 5984 1866 2488 2890 3059 7940 4 li 136 15 28 192 0 0 13 0 0 20 ,.0 0 14 0 ' 0 20 0 0 10 1 2 42 002 000 0 .0 0 006 002 006 005 0 0 '0 0 "0 1 004 00 1 00 1 0 0 2; 6 11 156 4 3 5 98 3 23 51 209 5 62 112 283 6 0 0 7 1 1 2 37 2 0 0 91 0 1 27 1 7 13 82 a 1 229 255 a 7 69 170 3 184 4X) 37 1 75 190 3 1 295 325 4 5 10 90 3 3951 403 286 494 454 452 411 . . 568 I 251) 587 265 623 1 424 759 1 8871 1317] 14601 12531 971 842,'1178] 1280 1140 981 i 432] 691 .711 6041 .412 4981 3871 756| 670 774 716] 666 600 470| 386 5981 185 226 3391 469, 748 788 675| 467 332 603 619 483 296] 548 854i 861 719 546[ 227 65 410 176 458| 191 311151, 185; 65, 102 255 282 204 93 293 203 366 574 413 615, 600] 413 615| 246327 432 281 139] 291 285 553 586 463 270 123 334j 255 130 1601 361 247 150 261 512 401 177 375 254 171 390 287, 234] 462, 494 375 U42| 1190 944 5 8C 37 1 37 ( 64 567 1033 '1093 871 446 13131 1467 1338] 694 1389; 1524, 13841 754 676 731 682 301 799, 829j 732, 663 712 650 780 814 722| 287 264 278 916j 6421 945| 836, 677 697, 597l 610 410 505 704] 759 595 436 1061 1139 756 490 737j 786 612 455 654 716 643 537 9JO, 991 571 354 1050 1125; 624] 374 1003 1033] 763 489 930 977; 660 369 1329 1493 1087, 658 1339 1492; 990 531 1296 1451 1002 588 1203 1329 959 617 1427 1594 11471 680 1144 1187 1064 i 996| 720 1400 1427 1197 1006 669 1 f 338 236 332 405 86 81 62 72 168 428 299 286 313 454 m 193 229 129 327 232 274 341 315 460 410 0 0 0 0 : 97 66 106 166 6 12 5 8 35 312 160 118 171 350 56 60 58 18 91 52 66 102 100 165 155 1386 1464 1252 1165 841 603 334 .7283 7197 3238 3653 3090 3613 : 2573 4196 1679 628 965 2367 1501 2532 2355 1174 1315 2068 1352 1435 1909 6598 5650 `8051 8804 3538 4068 3364 '3922 5103 5367 4815 6318 5039 5857 4910 5585 1 Calgary........ \ Edmonton.. 1 Vancouver.. \ Victoria.................. 1 Prince Rupert- 1 Churchill......... ' Winnipeg....... . \ Moncton........... \ Saint John-- | Halifax........... - Fort William.. 1 Hamilton........ 1 London.............. i Ottawa............... I Toronto.............. I Windsor.............. 234 264 342 696 1224 459 657 446 462 5.4.6.,. 702 118711773 1609 1355 1215! 750 1593 1810 1504; 777 818 893 736] 498 738 815 689 504 893 9331 804 I 8091 645 2356(2604 12288 [2204 1530 480 428 326 365 521 1097] 330 -744il302`1829 21111 1775 1531 822 '397' 282 270 55a59g85o 89w73o06o 11123077/1e3 1i1o54z21s87|I31192369262(1! 111910?1 779928 540750: 264 9,650 222 10,285 1621 5,573 2371 6,485 357 7,063 672 17,148 2if67t1n8i 1Io0'S,90M8109 if?. 35 5*| 354 108 126 204 168 54 22? 1141 12S0jll68|l085 722 471 508 1143 816 843 1696 1307, 1178,1305 1200 1336 1582 1187 1240 1386 1063 1073 505 984 1494,1646, 1459 1256 604 425 817 795 1155 1172 1304, 1283 1206 1143 1072 995 768 888 651 642 726 669 582 S 567 322 307 310 341 251 2101 87,,567184 234 10,496 6 7,119 105 7,425 91 8,818 87 7,374 73 6,802 442 CHAPTER 18 1954 Guide Table 2. Average Monthly and Yearlt Degree-Days for Cities in the United States and Canada b (Concluded) State Station p!q..:. Yeabs cn o CO B Z I 6 p <! ft* 67* 7* 20* 17* 43 16* 167 68 322 e87| 648 1407 1587 1392 1050 1534 1696 1481 1305 ,1767 [2027 16351 <1908 2440 12666 |2159| -6 o m 29S 428 102 9,438 397 138 10,700 580 246] 15,355 Degree-days for cities in Canada were supplied by the Canadian Meteorological Division, Depart ment of Transport, and were computed from mean temperature normals. * Indicates actual degree- days for 1947. .' ; being prepared and must be found by surveying plans, by observation, or by measurement of the building. Values of U for use in this equation are the unit fuel consumptions per degree-day, obtained as a result of the collection of operating information and listed in Tables 4, 5 and 6. Atten tion is directed to the nature of these units in the next following sections. Unit Fuel Consumptions per Degree-Day The quantity of fuel used per degree-day in a given heating plant can be reduced to a unit basis in terms of quantity of fuel or steam per degree-day per thousand Btu hourly heat loss at design conditions. A less frequently used basis is quantity of fuel per (degree-day) (square foot of floor area). In fact any convenient unit can be used to relate the consumption to the degree-day and to the building. The choice of these units requires explanation, and some discrimination and judgment. If the volume basis is used, the net heated space is prefer able to the gross building cubage, since gross cubage includes outer walls and certain portions of attic and basement space which are usually un heated. In the absence of data on net heated volume, a figure of 80 per cent of the gross volume may be used to obtain the estimated net heated volume. The volume basis has been rather widely used primarily because it is simple to apply. In industrial buildings it is usually easier to ob tain the correct volume of a given building than to measure and evaluate the heating capacity of its heating system, or calculate its maximum hourly Btu loss. The comparison of buildings on a straight volume basis does not allow for variation in exposure, type of construction, ratio of exposed area, to cubical contents, and type of occupancy. It is inaccurate for esti mating purposes unless the buildings are of very similar nature. The calculated heat loss or the heating capacity of the installed radiation may be used as the unit. The use of the heating capacity of the installed radiation is of questionable value when referring to heat transfer surfaces -20 0.778 -10 0.875 0 1.000 +10 1.167 1.400 mlosiaghptear dpepgeraere. -dTahy.e uFnoirtefiqguuirveasleinntTbaubilldeisng4,s5a,nadnhde6atainreg psrearssoqnuaa, rtheolsoeoitnowl ararmdiactloimr aotrestohoauvseaulouwer de-sign beat losses and smaller radiator quantities than those in cold cities. Consequently, the unit figure in quantity of fuel per (square foot of radiator) (degree-day), is larger for warm localities than for colder regions. the northern cities have more radiator surface per given buildingand a higher seasonal degree-day total tt cities in the south, the total fuel per eeason will be larger for the northern city. Estimating Fuel Consumption for Space Heating 443 used in warm air furnace or central air conditioning systems. Where steam or hot water radiation is already installed, care should be exercised in using the installed radiation as the basis for estimating, since actual installed radiation may differ considerably 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. t/ouiiAuuiig uao vuiuuuipuuu Values of the Unit Fuel Consumption Constant (U) for gas are given in Table 4 for various gas heating values, and different types and sizes of heating plants. They are based on an inside design temperature of 70 F and an outside design temperature of 0 F, and apply only to these condi tions. For other outside design conditions corrections must be made by applying factors given in Table 3. The factors in Table 4, as corrected if necessary, are satisfactory for regions having 3500 to 6500 degree-days per heating 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.G.A. 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. In general, the larger the installation, the smaller the unit gas consumption becomes, and the values in the table should be used with care, if at all, in large gas-burning installations. Example 4: Estimate the gas required to heat a building located in Chicago, 111., where the heating season has 6282 degree-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 found to be 0.087 cu ft of gas per (degree-day) (square foot of hot water radiation). From Table 3, the correction factor is 0.875 for --10 F outside design temperature, hence, 0.875 X 0.087 = 0.076. By Equation 4, F = 0.076 X 1000 X 6282 = 478,000 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 inside design temperature of 70 F and an outside design temperature of 0 F. For other outside design temperatures, the constants in Table 5 must be multiplied by the values m Table 3 as explained under Estimating Gas Consumption. Values given in Table 5 assume the use of oil with a heating 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 5: Estimate the seasonal oil consumption of a boiler, designed for oil p'ug, in a building located in Toledo, Ohio. The building has a calculated heat oss of 240,000 Btu per hr. The oil heat value is 144,000 Btu per gal, and the assumed casonal efficiency is 80. The outside design temperature for Toledo is --10 F, and e lnside design temperature is 70 F. Solution: From Table 5, under 80 percent efficiency and in the bottom line, aid , ue f U is found to be 0.00383 gal per 1000 Btu hourly heat loss for 0 F outae temperature. The correction factor for --10 F outside design temperature 444 CHAPTER 18 1954 Guide from; Table 3 is 0.875: Solving 0.875 X 0.00383 = 0.00335. Making a further cor rection for the heating value, 0.00335 X = 0.00328 gal per 1000 Btu per hr calculated heat loss per degree- 'day. From Table 2, the total normal degree-days for Toledo are 6269. Since U is expressed in 1000 Btu, N is equal to 240. Substituting in Equation 4 F => 0.00328 X 6269 X 240 = 4930 gal. Estimating Coal or Coke Consumption : Coal or coke consumption estimates are made by following exactly the same procedure as for oil. Values of (/ are given in Table 6 which only apply to an inside design temperature of 70 F and an outside design tem perature of 0 F. A correction must be made for other conditions by use of Table 4. Unit Fuel Consumption Constants (TJ) fob Gas* . Based on O F Outside Temperature, 70 F Inside Temperature Hot Wateb Steam Wabm Air Heating Value of Gas Btu peb Cu Ft 500 535 800 1000 Cu Ft Gas per Degree-Hay per Sq Ft EDR Up to 500 to 500 1200 Sq Ft . Sq Ft 0.149 0.139 0.094 0.075 0.142 0.132 0.087 0.071 Over 1200 Sq Ft 0.134 0.126 0.085 0.068 Cu Ft Gas per Degree-Day per Sq Ft EDR Cu Ft Gas per DegreeDay per 1000 Btu ` Hourly Design Heat Loss Up to 300 Sq Ft 0.254 0.237 0.159 0.127 300 to Over 700 700 Sq Ft . Sq Ft 0.242 0.226 0.151 0.121 0.231 0.216 0.144 0.116 Gravity 0.896 0.840 0.560 0.449 Fan Systems 0.861 0.805 0.538 0.431 1 Therm Gas Consumption in Therms per Degree-Day 100,000 ____B__tu____ 0.000743 0.000709 0.00067E I. . 0.00127 0.00121 0.0011C 0.00450 0.00430 * Abstracted from Comfort Heating, American Gae Association, 1938 and 5 percent added for operation without night reduction of temperature. the multiplying factors in Table 3. Data in Table 6 are based on 12,000 Btu per lb coal, and for other heating values of coal 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 loss of 240,000 Btu per hr based on an inside design temperature of 70 F and an outside design temper ature of --10 F. What will be the estimated norma! seasonal anthracite or coke consumption for heating 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 0.0444 of coal or coke per 1000 Btu per hr heat loss per degree-day; Correcting for the outside design temperature of --10 F from Table 3, the value of 17 is 0.875 X 0.0444 = 0.0389. From Table 2,1) is 6218 and from the problem, N is 240.. Substituting in Equation 4, F = 0.0389 X 240 X 6218 = 58,100 lb. Fuel used over any period is, according to the theory of the degree-day, propor tional to the number of degree-days during the period. From Table 2, the average numbers of degree-days for November, December, and January in Scranton are 717, 1074, and 1162 respectively, a total of 2953. The yearly total is 6218, so that duriug these three months the estimated consumption iB 2953 X 58,100 = 27,600 lb, 218 Estimating Fuel Consumption for Space Heating Table 5. Unit Fuel Consumption*'Constants (U) fob Oil1 Based on 0 F Outside Temperature, 70 F Inside Temperature 445 Effjctenct m Pehckwt 70 Gal Oil per Sq Ft Steam Radiator. 0.00105 0.00092 Gal Oil per Sq Ft Hot Water Radiator... 0.00066 0.00058 Gal Oil per 1000 Btu per Hour Heat Loss. 0.00437 0.00383 * Based on a heating value of 141,000 Btu per gallon. ' b Abstracted by permission from Degree-Day Handbook (Second Edition, 1937), by C. Strode and C. H, B- Hotchkiss. Seven percent added for operation without night reduction of temperature and change to heat ing value of 141,000 Btu per gallon. - 6 Per degree day. Estimating Steam Consumption In estimating steam consumption the efficiency is generally assumed at 100 percent. If for low-pressure steam an average heating 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 tempera . ture (see Table 3) when the unit figures are in terms of heat loss but not when the values are in terms of building volume or floor space. Where the heat loss is calculated in Btu per (hour) (degree difference in temperature) the simple Equation 5 may be used: : where F = g.X 24 X D 1000 (5) F = pounds of steam required for estimate period. II = calculated heat loss, Btu per (hour) (degree diSerence). 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 takes care of average inside and outside temperature difference. When degree-days are taken from Table 2, an average inside temperature .of approximately .70 F is assumed throughout the period. If an average inside temperature other Table 6. Unit Fuel Consumption* Constants (U) fob. CoALb . Based on 0 F Outside Temperature, 70 F Inside Temperature Unitc Efficiency in Percent 40 hb Coal per Sq Ft Steam Radiator .. 0.0216 hb Coal per Sq Ft Hot Water Radiator.. 0.0135 L^al Per 1000 Btu per Hour Heat 50 0.0172 0.0108 60 0.0143 0.0091 7 0.0123 0.0078 SO 0.0108 0.0068 0.0717 0.0592 0.0507 0.0444 b?v8edon a beating value of 12,000 Btu per pound. . ,, , _ 1^. v'1bstr&cted by permission from Degree-Day Handbook (Second Edition, 1937), by C. Struck and C. H. B. 0l9kias. Eight percent added for operation without night reduction of temperature. . degree-day. 446 Tablet. CHAPTER 18 1954 Guide . Consumption of Buildings with VabiousTtpes^fOccupancy; -------------------------- Ttpb of Building I Steam for' | Average Heating 1 No. Volume Heated Average Hours of . Bldgs. Space Lb per DD Occupancy 1000 Cu Ft per 1000 CuFt Office and Printing.................................................... Department Store......................................... 334 8 7 26 16 73 63 24 73 51 22 Manufacturing............................................. School........... :.............................................. Municipal or Federal ................................ 9 4. 8 15 12 7 2160 3000 .1895 4950 806 3400 310 865 2230 1795 1425 1240 1350 656 3306 1115 3215 880 0.685 0.577 1.230 0.412 0.786 - 0.385 0.624 0.588 . 0.990 0.962 0.482 0.202 0.808; 0.532 1.194 0.592 0.587 0.390 0.479 12.1 13.1 17.7 12.9 13.2 11.7 11.1 10.0 . 9.4 22.3 21.8 12.9 21.4 <9.5 - 7.9 ' 22.0 11.5 15.6 , 12.4 21.4 * Principles of Economical Beating, National Association of Building Owners and Managers. 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 temper-,, ature difference). What is the estimated average yearly steam consumption for buiSldoinlugtiohne:atSiningc?e the average inside temperature is approximately 70 F, the degreedays from Table 2, based on 70 F may be used. Therefore, from Table 2, Pittsburgh has 5430 degree-days per normal season. Inserting in Equation 5: 10,500 X 24 X 5430 1,368,000 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 aver-, ages, and for small groups in each type, the figures may need considerable modification to allow for local variations. It should be especially noted that the steam used for heating water for service is not included in the values given in Table 7. -- Example 8: A store in Philadelphia with a heating system designed to maintain 70 F inside 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 4739 degree-days per normal year. Inserting in Equation 4: F = 0.624 X 250 X 4739 = 739,000 lb of steam. . Degree-Day as an Operating Unit The degree-day is also widely used as a means of comparing the efficiency of the fuel consumption of one period with another for the same buildinQ- Estimating Fuel Consumption for Space Heating 447 Since the fuel consumption is proportional to the weather (degree-days), and since the periods to be compared may not have the same weather con ditions, the comparison can be made 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 proportional to the number of degree-days, plant operators frequently compute each month the fuel burned per degree-day by the heating plant. The resulting unit value, by eliminating the outside temperature variable, indicates whether the operating efficiency of the plant is above or below the previous month or year. The figures in Table 8 illustrate a typical example of a method of using the degree-day for making heating comparisons for one building for two Table 8. Heat Consumption Record for Comparison Col. 1 Col. 2 Col. 3 Col. 4 Col. 5 Col. 6 Col. 7 Total Consumption Consumption Fob Heating _ Avg Temp. Deo Date Lb/Dbq 65 F Base Dat Lb/Dbq M CuFt Sept.......... 337,500 7C4 Oct............ Nov.......... 834,200 1,446,600 o oa Dec....... 2,176,400 3 Jan........ :. 2,332,200 Feb........... 2,131,100 0 Mar........... 2,021,900 Apr........... 1,241,500 May.......... 672,500 258.600 July.......... 188,400 180,100 170,500 667.200 1,279,600 2,009,400 2,165,200 1,964,100 1,854,900 1,074,500 505,500 91,600 65 53 44 25 22 28 31 43 55 146 339 641 1,233 1,297 1,106 1,032 647 303 50 1,170 1,966 1,990 1,630 1,670 1,775 1,799 1,660 1,670 1,830 0.575 0.970 0.982 0.804 0.822 0.888 0.885 0.818 0.822 0.905 13,821,000 Sept.......... 330,200 Oct............ 887,100 5 Nov.......... 1.525,200 Dec........... 2,045,500 Jan............ 1,933,400 Feb........... 1,990,200 Mar........... 1,934,100 146,200 703,100 1,341.200 1,861,500 1,749,400 1,806.200 1,800,100 61 52 39 28 30 30 31 167 410 812 1,120 1,044 1,111 1,021 875 1,718 1,653 1,660 1,670 . 1,624 1,760 0.431 0.845 0.815 0.817 0.825 0.800 0.868 ' If, for example, the heat consumption in March, 1943, is compared with that in March, 1944, it will be found that in the latter the steam consumption is 1799 -- 1760 = 39 lb less which is a decrease of 2.2 percent. consecutive heating seasons. The heat quantity figures inserted are pounds of steam, but a similar comparison could be made using pounds of coal, gallons of oil, or cubic feet of gas. For such a comparison, a two-year record, as shown in Table 8, is often used. The year under consideration may then be compared, month by month, 1 with the previous year. Column 3, Consumption for Heating, would be used if the same fuel is used for heating and process steam. Some reason able figure must be assumed for the process requirement and should be deducted from the amount shown in column 2. This would leave in column 3 only the fuel chargeable to heating. The degree-day values in column 5 are obtainable from the local Weather Bureau. Values in column 6 are obtained by dividing corresponding values in column 3 by the degree-days m column 5. The heating index in column 6 is, then, a figure of heat con sumption, corrected for outdoor temperature, and should be relatively con stant month by month. Column 7 in Table 8 may be used if the heat consumption is to be compared on a building volume basis with average values shown in Table 7. CHAPTER 18 1954 Guide 448 Various Cities of the Table 9. Degree-Days fob Industrial Heating in , - . ; . . United States* Annual Totals for a Normal Heating Season. Estimating Fuel Consumption for Space Heating 449 Table 9. Degree-Days for Industrial Heating in Various Cities of the United States (Continued) Annual Totals for a Normal Heating Season. State City DeqbeE'Days 45F 55F Base Base State City Degbes-Dayb 45F 65F Base Base Pierre......................... .. Rapid City...... ........... Yankton....................... 3743 3162 2590 2898 5678 Vt. 5234 4628 6045 fa- Knoxville...................... Memphis.'...................... Nashville...................... 242 1398 431 166 1741 1284 Wash. .419 , 1678 Tex............ Amarillo.......... .......... . El Paso......................... Fort Worth.................. Galveston..................... Houston........................ San Antonio................. 786. 32 . 915 2220 919 W. Va. 754 43 110 . wis. .484 305 Utah...... .. Salt Lake City....... . 1978 3981 Wyo. 1475 3202 Burlington......... Northneld.......... Lynchburg......... Norfolk............... Richmond.......... North Head....... Seattle................. Spokane........... Tacoma............... Walla Walla....... Elkins................. Parkersburg....... Green Bay........ La Crosse........... Madison.............. Milwaukee......... Cheyenne........... Lander................ 3014 4984'' 3652 7121 554 1928 260 1496 540 1895 1741 507 1506 1147 3318 3034. 3067 2657 2500 3208 2185 3672 2365 2565 3327 2784 5331 3992 4850 4617 4700 5450 * From Degree-Day Handbook By C. Strock and C. H. B. Hotchkiss (The Industrial Press, pp. 132-134). INDUSTRIAL DEGREE-DAYS When estimating the heating requirements of warehouses, factories, and other buildings where the inside temperature to be maintained differs greatly from the usual inside temperature 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 9 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 ls to be maintained 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 the difference in degree-days is not too great, and where the known fuel consumption of one building may be used to 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 tipon the maximum demand of the building. The maximum demand may ^ measured in several different ways. It may be taken as the instantanepus peak or as the rate of use during any specified interval. One method e * the average of the three highest hours during the winter. These "gures are shown for a number of buildings in Detroit in Table 10.12 These maximum demands were measured by an attachment on the conensation meter, and therefore represent the amounts of condensation trough the meter in the highest hours, rather than the true rate at mch 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 tierever this has been investigated it has been found to be negligible. 450 CHAPTER 18 1954 Guide |S b< Table 10. Biih.piso.Loap Kactohs and Demands of Some Detroit Buildings Building Classification Load Factob j Lb or Demand per (Houb) (Sq Ft of Equivalent Installed Radiator Subface) Clubs and Lodges................................................................ Hotels.. -. .1....................................... ........................ 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 , qff `'is- 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 10, the % theaters, operating for short hours, have a load factor of 0.126 as compared J - with the figure of 0,318 for clubs and lodges. 5 REFERENCES :f 1 Comfort Heating {American Gas Association, 1938). V * Are Automatic Air Shutters Justified on a Gas-Fired Conversion Burner? by ^ W. M. My)er, JK and H, W. Nelson (A.STI.V.E. Transactions, Vol. 55,1949, p. 111).. 3 Efficiency of Bituminous-Coal-Burning Space Heater, by J. W. Tieman and- F. L. Bagby (A.S.H.V.E. Transactions, Vol. 57, 1951, p. 89). /., 4 Heat Losses and Efficiencies of Fuels in Residential Heating, by R. A. Sherman-: and R. C. Cross (A.S.H.V.E. Transactions, Vol. 43, 1937, p. 185). v The Stoker-Fired Warm-Air Furnace in the Research Residence, by S. Konzorv (University of Illinois, Engineering Experiment Station, Circular 39, 1939, p. 98). =g,- Performance of a Hot Water Heating Svstem in the I = B = R Research Home at'v. the University, of Illinois (University of Illinois, Engineering Experiment Station, Bulletin No. 349, Jan. 4, 1944). .V 7 Fuels and Burners (University of Illinois, Small Homes Council, Circular G3-5,'1 Jul8yIn1v94e9s)t.igation of Oil-Fired Forced-Air Furnace Systems in the Research Resi dence, by A. P. Kratz and S. Konzo (University of Illinois, Engineering Experiment ; Station, Bulletin No. 318, Nov. 7, 1939). 9 Graphical Method of Calculating Heat Losses, by Paul D. Close (A.S.H.V.E.^|. Tr1a0nHsoaucsteionHse, aVtionlg. 49(I,n1d9u43s,trpia. l34G5)a.s Series, American Gas Association, Third''; Edition). ^ 11 Report of Commercial Relations Committee (Proceedings, National District HelattiTnhgeAHsseoactiaRtioenq,u1ir9e3m2)e.nts of . Buildings, by J. H. Walker and G. H. Tuttle..-. . (A.S.H.V.E. Transactions, Vol. 41, 1935, p. 171). ' ; .: ' II - `C. -V CHAPTER 19 GRAVITY WARM AIR SYSTEMS Warm Air Leaders, Stacks, and Registers; Return Air Grilles, Ducts, and . Connections; Outline of Design Procedure WARM air heating systems of the gravity type are described in this chapter.1 In these systems the motive head producing flow depends upon the difference in weight between the heated air leaving the top of the casing and the cooled air entering the bottom of the casing, while in the forced air type a fan may supply all or part of the motive head. A gravity warm-air furnace heating plant consists of a fuel-burning . furnace or heater, enclosed in a casing of sheet metal, which is placed in the basement of the building. The heated air, taken from the top or sides near 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. A-sectional view of a typical plant showing good installation practice is given in Fig. 1. The air supply to the furnace is usually taken entirely from inside the building through one or more recirculating ducts, although in some cases an outside air supply duct is provided. WARM AIR LEADERS, STACKS, AND REGISTERS In a gravity circulating warm-air furnace system, the size of the leader pipe to a given room depends upon the heat loss from the room, the equiv alent length of the leader, and the temperature of the warm air entering the room at the register. For most successful operation, the furance should be centrally located with respect to register and stack positions so that the leaders will be of uniform length and as short as possible, in which case the frictional resistance to air flow and the temperature loss from the ducts will be about the same for all leaders and stacks. Originally, the design was based on the heat carrying capacities per square inch of leader pipe area with register air temperatures of 175 F. ' Later, in the revision of the entire design procedure, as shown in the section entitled, Outline of Design Procedure, the carrying capacities of leader pipes nave been expressed directly in terms of Btu per hour. In general, it is necessary to use two or more leader pipes to rooms requiring more than the capacity of a 12 in. round pipe. The tops of all sizes of leader pipes should be cut into the furnace bonnet at the same elevation. Leaders over 12 ft in length, or having a large number of elbow fittings should be avoided if possible. In cases where such leaders are necessary, it is recommended that smooth transition fittings be used, and that duct insulation be applied. Asbestos paper, unless of the corrugated type, should not be considered as insulation. To assist in balancing the air distribution of the system, a damper should be placed in each leader 451 452 CHAPTER 19 1954 Guide pipe except one although it is sometimes omitted in one leader connected to a room heated at all times. ' / In a gravity circulating system, the ratio of stack to leader area is quite important, although little is gained by providing wail stacks with areas in excess of 75 percent of their connected leader pipe area. In mostcases Fig. 1. A Sectional View of'a Typical Plant Showing Good Installation Practice* A. House chimney, no bends nor offsets. B. Top ol chimney at least 2 ft above ridge of roof. C. Flue lining, fireclay., D. All joints air tight. E. At least 8 in. brick. F. No other connection beside ;that to furnace. G. Cleanout frame and door, airtight. H. Smoke pipe, end flush with inner surface of flue. I. Draft door. J. Use flue thimble. K. Casing body. L. Casing hood or bonnet, top of all leader collars on same level. M. Round leader, pitch 1 in. per foot N. Sleeve with air space or 1 in. of nonoofo* bustible insulation around leader where P ing through wall. O. Dampep in ail leaders. P. Transition fittings. -fg Q. Rectangular wall stack. R. Baseboard register. S. Distributes pipes equally around bonnet. r, V T. Floor register. U. Return air face. . -,U> V. Panning under joist. W. Transition collar. . X. Round return pipe. Y. Transition shoe. . , ' )1' Z. Top of shoe at casing not above grate level. : - * From NWABAACA Manual 5: Gravity Code and Manual. Fourth Edition, I960- ,-*d a 31 in. X 12 in. stack is the largest which can be installed in normal 'w&U construction. Hence, any room having a heat loss much' in excess of flOOP Btu per hr, will require two or more stacks, or one oversized stack built into a 6 in. studding space, providing the design register temperature is to o| retained at the average value of 175 F, which has been recommended. Registers used for discharging warm air into rooms should have a area not less than the area of the leader pipe to which the register is a*i Gravity Warm Air Systems 453 tached. First story registers should be connected through boot and register box extensions having areas at least equal to leader areas. Upper story registers should be of the same width as the wall stack, and should be placed either in the baseboard or sidewall, preferably without offsets. First story registers may be of the baseboard or floor type, with the former location preferred. Leader pipes or stacks intended to heat two rooms are not recommended. RETURN AIR GRILLES, DUCTS, AND CONNECTIONS The placement and number of return grilles will depend upon the size, details, and exposure of the house. Small compactly built houses may be adequately served by a single return grille effectively placed in the central hall. It is usually desirable to have two or more returns, provided that in two-story residences one return is placed to receive effectively the return air at the foot of the stairs. A return air connection must be carried to any room whose floor level is below that of adjacent rooms. Return ducts from upstairs rooms may be necessary in spaces which are closed off from the rest of the house, or which have much outdoor exposure. Return grilles on different floor levels should not be connected to the same vertical return duct. The return air grilles should have free areas at least equal to the ducts to which they connect, and should be installed in the floor, or in the base board with the top edge of the grille not more than about 14 in. above the floor line. As frictional resistance in the return air system is as detrimental as resistance in the warm-air system, care should be exercised in locating return air grilles which require long return ducts. The frictional resistance of the long ducts used in parallel with short return ducts must be reduced to compensate for the length. This is ac complished by using design data given in the following section, Outline of Design Procedure. The ducts through which air is returned to the furance should be designed to minimize resistance to air flow. They should be of ample area, with sizes selected according to capacity and construction, as specified in section, Outline of Design Procedure, and should be streamlined. Horizontal ducts should pitch at least \ in. per foot downward toward the furnace, avoiding fittings which would require lifting of the return air after the duct has passed under some obstacle. Ducts returning air to the furnace should be protected from heat sources fending to reheat the return air. If the duct must be run over the top of the furnace, or above the vent pipe from the furnace, insulation should be interposed between the heat source and the duct., The top of the return shoe should enter the casing below the level of the fFate of a coal furnace, and not more than 14 in. above the floor of an oil or gas furnace. It must be wide enough to retain proper area. OUTLINE OF DESIGN PROCEDURE data underlying the design procedure are given in detail in a circular2 "Sued by the University of Illinois. In this procedure the design of the arm-air duct system is considered as an entire unit, so that for a given ea'i Ioss the sizes of leaders, stacks, boots, stackheads, and registers are 454 CHAPTER 19 1954 Guide1' .. . -'.`j. Table 1: First Story Warm-Air Ducts* . Register Size, In. ' COMBlNATTOJV Leapea Pipe . No. . Diameter, In. Baseboard Size Extension ' Throat Size 1 2 3 4 -5 . 8 9 10 12 14 8 x 10 9 x 12 10 x 12 12 x 14 14 x 16 10 x 8 12 x 8 12 x 9 13 x 11 254 254 354 554 654 x 10 654 x 12 m x 12 954 x 13 * When the calculations indicate a requirement for a given room greater than Combination No. 4, two or < more smaller units totalling the required capacity are recommended. . Table 2. Second Story Warm-Air Ducts--Single Wall Stacks and Fittings, Combi nation No. Leader Pipe Diameter, In. ; Stack*1 Size, ' In. Floor ' Register Size, In. . Baseboard Size Extension Sidewall n8 12 9 14 ! 10 15 12 16 12 10 x3U 12 x 354 14 x 3*4 12 x 5J4 14 x 5)4 8 x 10 9 x 12 10 x 14 10 X 8 12 x 8 13 x 11 12 x 9 13 x 11 214 214 254 354 554 10 x 8 12x8 b Recommended stack sizes. Tables may also be applied to 3 in. and 3 1/2 in. stack depths. Table 3. Second Story Warm-Air Ducts--Double Wall Stacks and Fittings Combi nation No. Leader Pipe . Diameter, In. Stack Sizb. In. Internal External Floor Register Size, In. Baseboard Size Extension Sidewall 21 '8 2*4' x 10 354' x 1054 8 x 10 22 .8 ' 3 x 10 3^4 x 1054 8 x 10 23 . 9 2*4* x 12 354' x 1254 9 x* 12 24 9 3 x 12 354 X1254 9 x 12 c Commercial sizes vary 1/& in. from values shown. 10 X 8 10 x 8 12 x 8 12 x 8 . 254 254 254 254 10x8 10 x 8 12x8 12 x 8 i all correlated. Similarly in the case of return ducts, the selection specifies a complete unit consisting of return grille, return duct, and shoe connection. Recommended Standard Sizes For the purpose of simplification and standardization, selected combina tions of commercial sizes of warm air pipes, return air pipes, ducts, grifiSi fittings, and registers are designated as Combination Numbers. The numbers assigned and the combinations selected as standard are listed m the following Tables 1 to 4 inclusive.3 The selected types of boots are shown in Fig. 2, and their resistances ex pressed in equivalent elbows are shown in Table 5. It is essential tWt free areas be maintained throughout fittings. Figs.^ 3 and 4 show recommended practice as given in Manual 5 of tbe Gravity Warm Air Systems Table 4. Return Air Ducts' d Based on 14 in. space between joists. . * Use full depth of joist except when joist depth is less than minimum depth required, when pan must be used, . NWAH <fc ACA. For construction, design features, and ratings, of gravity furnaces see Chapter 16. Carrying Capacity cine W SK*. ||P Fig. 2. Typical Warm Air Boots 456 CHAPTER 19 .1954' Guide Vt ' Table 5. Wakm Are Boot Resistances of Wahm Aik Boot Combinations Expbesseb ... P.TTTTTlTPXlTe Name o? Combination EcjinvALEUT I[ . 6NE0lo-b.DoeowQrs'?' 45-Deg Angle Boot and 45-Deg Elbow 90-Deg A.ngle B. oo,,ti no T?1 Kmu Eiid Boot Offset Boot 45-Deg Angle Floor Register--Second Story Offset Offset Supporttojoisi or celhna " Z` or /e5$. `'Masonry Petal thimble. ' Cottpr Fio. 4. \ ^^tTjotntyJaped h/ith asbestos paper KTight collar . Details op Bonnet and Leader of Gravity Warm-Air FubnAC* n?WrM NWAH & ACA Manual 5, Fourth Edition) , Gravity Warm Air Systems 457 Table 6. Warm Air Carrying Capacity, Btuh Delivered, First Story Registers Actual Length (Bonnet to Boot) Feet Combi nation No. 1 2- 3 4 5 ! 2 3' 4 5 1 2 3 4 5 1 2 3 .4 5 2 3. 4 5 ,No. OF Elbows 6, 6H 7 4 6 8 10 4 6 8 10 12 14 4 6 8 10 12 14 16 18 m * - 4 6 8 10 12 14 16 18 20 22 1 6,020 5,850 5,680 5,510 5.340 5,170 5,000 4,830 4,660 4,490 7,620 7,400 7,180 .6,970 6,760 6,540 6,320 6,110 5,890 5,880 . I 9;400 9,140 8,870 8,600 8.340 8,070 7,810 7,540 7,270 7,010 . 13,350 12,970 12,590 12,210 11,830 11,450 11,080 10,700 10,320 9,950 - 7 17,520 17,020 16,530 16,040 15,550 15,050 14,550 14,050 13,560 13.060 ' .9- 5,850 :5,660 5.490 5,330 5,160 5*000 4,840 4,670 4,510 4,340 7,360 7,150 6,940 6,730 6,520 6,320 6,110 5,910 5,700 5;500 2 'o 9,090 8,840 8,580 8,320 8,060 7,800 7,550 7,290 7,040 6,780 a . 12,910 12*540 12,170 11,800 11,430 11,060 10,690 10,320 9,950 9,580 16,940 16,450 15,990 15,500 15,040 14,550 14,080 13,600 13,120 12,650 i i 5,620 5,460 '5,310 5,150 4,990 4,830 4,670 4,510 4,350 4,190 <3 7,120 6,910 6,710 6,510 6,310 6,110 5,900 5,700 5,500 5,300 3 8,780 8,530 8,280 8,030 7,780 7,530 7,290 7,040 6,800 6,550 ' -8 *' 12,450 12,100 11,750 11,400 11.050 10,700 10,350 10,000 9,650 9,300 o ' 16,360 15,900 15;440 14,970 14,610 14,050 13,600 13,130 12,660 12,200 a ' -a 5*420 5,260 5,110 4,960 4,800 4,650 4,500 4,350 4,190 4,040 6,860 8,660 6,460 6,270 6*080 5,890 5,690 5,500 5,300 5,110 , 4 8,460 8,220 7,980 7,740 7,500 7,260 7,020 6,780 6,550 6,310 j 12,010 11,670 11,330 10,990 10,650 10,310 9,970 9,630 9,290 8,950 - a 8 15,770 15,320 14,880 14,420 13,990 13,540 13,100 12,650 12,200 11,750 5,240 5,090 4,940 4,790 4,640 4,500 4,350 4,200 4,050 3,910 bC '5 M 6,630 6,440 6,250 6,060 5,880 6,690 5,500 5,320 5,130 4,940 8,180 7,950 7,720 7,490 7,260 7,030 6,800 6,560 6,330 6,100 11,610 11,290 10,950 10,620 10,300 9,970 9,640 9,320 8,990 8,660 15,250 14,800 14,380 13,950 13,520 13,090 12,650 12,230 11,800 11,370 Note*: Carrying capacity and length of run increased with basement depth. ., of trunk and carrying capacity of gravity extended plenum installations should be based on *ne 6 ft basement depth capacities. ' .. Design Procedure . The steps to be taken in designing a gravity warm-air duct system are: 1. Calculate the heat loss from each room as explained in Chapters 9, 11 and 12. 2. Prepare a layout showing (a) furnace, (b) chimney connection, (c) warm air registers (whether floor, baseboard or wall), (d) return air grilles. 3. Indicate on each warm-air leader (using symbols shown in Fig. 6): (a) whether fte room to be heated is on first or second story ; (6) the approximate length of leader P>pe m the basement; (c) the number of right angle elbows and equivalent elbows (Table 5) required, including the elbow at the boot connection (see Fig. 2); (d)' whether the register is to be located in the floor, in the baseboard, or in the wall. 4. Show the number and proposed locations of return-air grilles and the type of return-air system (see Fig. 5). 5. From Table.6, for first story, or from Table 7 for second story, select the comnation number for the warm air system which will supply the heat required to each room, with the number of elbows and length of leader pipe previously deter mined. Then, using the combination number as found, read directly in Tables 1, ' or leader, stack, and register sizes required. 6- Prom Table 8 select the combination number for the return-air system to cor respond with the Btu per hour serviced and the type of return-air system. Then Table 4 select the duct and grille sizes, etc., corresponding this number. 2 Select a furnace having a register delivery, in Btu per hour, equal to the total ' loss from the structure. CHAPTER 19 1954 Guides 458 an.i *-'**> ?"22=-; Gravity Warm Air Systems 459 16 i I - r--r-T-~l | , , . ___ ; Notes: When floor registers are used on second story rooms, include the equivalent elbow .resistance for theCcroomssb-ionvaetriocnonNnuemctbioenrsas21shaonwdn23inasFsigh.o2w- n in Tables 2 and 3 are compos'ed of narrow stacks for na- rrow For Combination No. 21, the capacities are the Btuh deliveries shown for Combination Nos. H or " stud spaces. muFltioprliCedombbyin0a.8t3io. n No. 23, the capacities are. the Btuh deliveries shown for Combination Nos- 12 or... multiplied by 0.83. Standard work sheets to facilitate design according to the recommended procedure, are available from NWAH & ACA. Table 8. Return Air Com bination No. Duct Diam. In. 31 10 32 12 33 14 34 16 35 18 36 20 37 22 38 24 Return ^Carrying Capacxty-BtuhS^ceb Type A BTUH BTypes Cand BTUH Type D BTUH Type B BTUH Type F , btuh Brnm-" Aw Cob- bib*tio> 11.300 16.300 9,500 13,700 7,800 11,300 5,000 7,200 7,800 11,300 31 32 22,200 29,000 18,700 24,400 15,300 20,000 9,800 12,800 15,300 20,000 33 34 36,700 45,300 30,800 38,000 25,300. 31,300 16,200 20,000 25.300 31.300 35 36 54,800 65,200 46,000 54,800 37,800 24,100 45,000 1 28,700 37,800 45,000 37 38 ' T"-- h Tin* ( Tnw.F Note: For Types C, D, E, and F leturn-air systems, reduce the carrying capacities shown in Table 8 by 1 percent for each 4 ft additional* length "in the horizontal run. ' Fig. 5. Typical Arrangements op Return-Aib Duct Systems Design of Extended Plenum Systems The extended plenum system of gravity warm air heating employs horizontal ducts in the basement leading from an enlargement or extension of the customary plenum to the risers which distribute the conditioned air to the various rooms. Extended plenum gravity systems have been satisfactorily designed and installed in small compact houses where the heat losses do not exceed 65,000 Btuh. The dimension from the floor to the bottom of the joists should in every case be at least 7 ft. To design such a system the procedure is the same as for the conventional system already described in this chapter. It is understood that the length of leader pipe is measured from the register to the furnace. For takeoffs, use standard fittings designed for Fig. 6. Typical Basement Line Drawing '460 CHAPTER 19 1954 Guide extended plenum connection and allow the equivalent length of one 90 deg elbow. To size the extended plenum, start with a trunk of standard 8-in. depth and the rectangular equivalent of the last branch, and then, proceeding toward the furnace, increase the width of the .trunk according to Table 9 for each succeeding branch connected until all branches on that trunk have been considered and the width of the trunk required has been deFteormlloinwedth. e same procedure for`each trunk. The largest size so deter mined is selected as the size of the extended plenum for the system. Return air intakes are to be sized by the same method as for conventional gravity systems. . Table 9. Rectangular Equivalents op Round Pipe and Increase in Width op 8-In. Depth Extended Plenum Commercial, Round Pipe Diameter ' - Inches Equivalent Rectangular . Duct Size Inches Increase in Width of Trunk Duct Having &-In. Depth Inches 5 6 ' '7 8 9 10 12 3x8 4x8 5x8 7x8 8x8 11 x 8 15x8 i 2 3 5 5 8 12 Design Examples , Examples 1 and 2 will illustrate the use of the tables in selecting warm4ir and return-air system sizes. . Example l: For a room which has a heat loss of 22,500 Btu per hr, select the sire of first story warm-air system. There are three elbows, and the leader is approxi mately 10 ft long. . .. Solution: Since 22,500 Btu is beyond the capacities shown in Table 6, it is neces sary to select two units of 11,250 each. From Table 6 in 10 ft leader column, and in section for three elbows,-find 11,400 as nearest capacity which corresponds to Com bination Number 4 in first column. Refer to Combination Number 4 in Table 1 and find that the leader should be 12 in. in diameter, and should be used with a 12 X 14in floor register or a 13 X 11 in. baseboard register with a 5j in. extension. Example 2: What is the size of a.return-air system of Type D which is to serv iceS3o5l,u00ti0onB:tuFrpoemr hTra?ble 8'f;ind Combina'tion Number 37 which will service 37,80, 0 Btu per hr. Refer to Table 4 to find that Combination Number 37 will require a 22-in. diameter duct, a shoe area of 420 sq in., a metal grille 18. X 30 in., a duct X 10 in. or 36 X 12 in. If joist lining is used the minimum depth should be 15 m- for two 2-joist spaces 14 in. wide, or 10 in. for three joist.spaces. REFERENCES `The engineering data were .obtained from University of Illinois, EngincertM Experiment Station Bulletins Nos. 141,188,189 and 246; Warm Air Furnaces and Heel ing Systems, by. A. C. Willard, A. P. Kratz, V. S. Day, and S. Konzo. See als Manual 5: Gravity Code and Manual for the Design and Installation of Gravity Warm Air Heating Systems, 4th Edition, 1950, published by the National Warm a Heating and Air Conditioning Association. * Simplified Procedure for Selecting Capacities of Duct Systems for Gravity Air Heating Plants, by A. P. Kratz and S. Konzo (University of Illinois, Engined": Exp* eGrirmaevnittySCtaodtioenanCdirMcualnaur a4l5f,oDr ethce., D1e94s2ig).n and Installation of Gravity Warm Aj* Heating Systems, Manual 5, 4th Edition, 1950, (National Warm Air Heating and CnnAitinnmo Association). '" CHAPTER 20 FORCED WARM AIR SYSTEMS Air Distribution, Standard Combinations of Parts, Simplified MethocP of Design) Design Procedure for Large Systems, Automatic Controls, Adjustment of System for Continuous.Air Circulation, Ceiling Panel Systems, Perimeter.Systems, . ....... . Cooling Methods, Design of Cooling System. ............... IN forced warm air or fan furnace heating systems, the air circulation is effected by motor-driven centrifugal fans, commonly referred to as blowers. The advantages of forced air systems, as. compared with gravity systems, are; 1. The furnace need not.be centrally located but may be placed in any part of the basement. - 2. Basement distribution ducts can be made smaller and can be so installed as to give full head room in all parts of the average basement, or be completely concealed from view where desired. . 3. Circulation of air is positive, and in a properly designed system, can be balanced in such a way as to give a greater uniformity of temperature distribution. 4. Humidity control is more readily attained. 5. The air may be cleaned by sprays or filters, of both. 6. The fan and duct equipment may be utilized for a complete cooling and dehumidifying system for summer, using either ice, mechanical refrigeration, or low temperature water for cooling and dehumidifying, or adsorbers for "dehumidifying. . 7. The use of the fan increases the volume of air which can be handled, thereby increasing the rate of heat extraction from a given amount of heating surface and insuring sufficient air volume to obtain proper distribution in a large room. 3. Ventilation air may be positively introduced and heated. 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 16 and other publications.1 ' AIR DISTRIBUTION The conditions of comfort obtained in a room are influenced greatly by the type of register used, and the locations of the supply registers and return irilles. In general it has been found that, changes in the type, air velocity, ^ud location of the supply register affect the room conditions much more than the-changes in the location of the return grilles. One method is to locate the supply register near the floor, or high in the side wall, so that the ^ann air from the register blankets a cold wall, and mixes with the cold air descending from the exposed walls and glass. Another method is to locate the supply openings near the floor, or high in the side wall, on the inside Wa`l, and the return openings near the greatest outside exposure. Still ^bother method is to locate all supply openings around the outside wall, ,ear the source of the greatest heat loss, usually, beneath the windows, and o use grilles designed to blanket the cold area. This causes mixing of ue warm air delivered with the cool air from the heat loss area and the 461 462 CHAPTER 20 1954 Guide cold air from infiltration thus effectively preventing drafts. This has been called perimeter heating. In any case, the warm air registers should be located so that the air stream never discharges directly against people at rest. Tests2 in Warm Air Research Residence No. 1 at the University of Illinois, have indicated that continuous blower operation gave better re sults than intermittent operation. Register and Grille Openings \ Tests also conducted in Warm Air Research Residence No. 1 have in dicated that comparable results are obtainable with either high side wall or baseboard registers, if proper registers and air velocities are selected. Baseboard registers should be of a deflecting-diffuser type.which throw the Forced Warm Air Systems 463 of Manual 7, these manuals being publications of the National Warm Air Healing and Air Conditioning Association. _ . . Registers should be well proportioned and decorated to harmonize with the trim. Air supply registers should be 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 Healing and Air Conditioning Association. Return air grilles may be located in hallways, near entrance doors, under windows, in exposed comers, or inside walls; depending on location of supply registers. Baseboard returns are preferable to floor grilles where warm air registers are located on inside walls. Where perimeter heating is used, returns placed high on inside walls are preferred. . , Fio. 1. Recommended Type of Baseboard and Low Sidewall Installation on, . Warm Wall* . * Vertical bars with ustable deflection, or fixed vertical bars with deflections to right and left not exceeding about 22 deg. For low sidewall location, the deflection for horizontal, multiple valve register should not exceed 22 aeg. For baseboard locations, the deflection for horizontal, multiple valve registers should not exceed about 10 deg. . air downward toward the floor and diffuse it at the same time. For base board registers, air temperatures under 125 F, and air velocities over 500 fpmH,igshhosuidlde wbealal vreogidisetderassmthuesyt bmeaoyf csauucshe tdyrpaeftsth. at the air is delivered horizontally or in a slightly downward direction, and must be so located as to avoid impingement of air on ceiling or wall. Directional flow diffusing type registers should be used to insure best results. Register air velocities 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 atf uniformly over the register face. Basic rules for the location and selection of registers, together with explanations of factors affecting operation, are given* in Section III of Manual 4, Section III of Manual 10, or Section n Pig. 2. Recommended Type of High Sidewall Installation on Warm Wali> ^ Horizontal valves, in back or front, to give downward deflections not to exceed from 15 to 22 deg, Hampers 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 dampers are commonly used. Volume dampers are used to completely cut off or reduce the flow through ducts. Splitter dampers are used where a branch is taken off from a main trunk. Squeeze dampers are used for adjusting the volume of air flow and resistance through a given duct. It is essential that a damper with positive locking device be pro vided for each main or duct branch. Labels placed on ducts should indi cate the room being served. Damper positions should be marked for summer and winter operation, and to avoid tampering. Ducts The ducts may be either round or rectangular in cross section. The centerline radii of elbows should preferably be not less than one and oneuaif times the pipe diameter for round pipes, or the equivalent round pipe CHAPTER 20 . 1954 Guide s1i6z4e in the case of rectangular ducts. Warm air ducts passing through cold spaces or located in exposed walls, should have 1 to 2 in. of insulation. ::'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 canvas. 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. Instal lation of a fan directly under a return air grille is usually avoided. ' STANDARD COMBINATIONS OF PARTS The combinations of parte selected as standard by the National Warm At Heating and Air Conditioning Association are shown in Tables 1 and A;.ir A method for selecting these combinations is indicated in the following Simnlified Method of Design. ... _______ Fio. 3. Recommenced Type op Floor or Low Sidewall Installation on Osi- ' side Wall" , . : V"' . c Reg-isters: set to direct air upwa.rd alongthe wall at as wide an angle as possible. . -- ' SIMPLIFIED METHOD OF DESIGN ` 1 >r J, ii A simplified method for selecting the combinations of branches, boots, stacks, and registers, is given* in Manual 7 of the National Warm. An Healing and Air Conditioning Association. In this method, the. sizes of tt>e branch ducts are obtained from two tables giving their Btu capacities.; The proper combination of parts for each branch can be determined if the follow ing information is available. .. - a. Location of room, that is, whether on first or second story. ,6. Actual horizontal length of duct from bonnet to boot, in feet. -",tcc0di...M. BABECttqouuliuUf Ilitoevousqassnbuleoiffvnrr*ooa*t--mlmleennrrtgoot"loohemmsngit.tntoo_hesf--bbeeeeo*tfhhoeefifaatnttatiteen|lddlgf..fsitticnogmsmaonnd'lyo,futsheed rfeomgraistd.tAeormr.. esFtiicg.s4ysstehomws.s.. .e Forced Warm Air Systems 465 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 3 and 4 are based upon the most reliable data pertaining to fric tion losses and temperature drops in ducts.. They are also based upon a TOO deg temperature rise of the air, and a static pressure available for overcoming friction losses in the external duet system alone of 0.20 in. water gage. The use of this method assumes that the fan in the fanfurnace 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. The combination numbers shown in the right hand column of Tables 3 and 4 correspond to those given Table 1. Warm Air Duct System Combinations op Parts Selected as Standard Combina tion No. i- Branch Pipe, Size In. . Register Size, In. (See Figs. 1, 2, 3 and 4) Stack Size, In. Round Rec tangular Base-board High or Low Sidewall 2 34 5 Floor Registers* perimeter 1_ 6 REPLACE MENT 7 Required Increase in Width op Trunk Duct, In. 8 ` 41 10 x 3)4 5 3x8 10x6 4 x 12 8 x 10- i 42 10 x 3H 6 4x8 10 x 6 4 x 12 8 x 10- 2 43 12 x 3% 7 5x8 12 x 6 4 x 14 9 x 12- 3 44 14 x 3J 8 6x8 14 x 6 6 x 14 9 x 12* 4 or longer 45 10 x 3)4 9 8x8 (2) 10 x 6 (2) 4 x 12 10 x 12* 5 (2-Stacks) or (1) 24 x 6 46 12 x 3M 10 10x8 (2) 12 x 6 (2) 4 x 14 12 x 14- 7 (2-Stacks) or (1) 30 x 6 .. * Use these items only when the installation necessitates the use of existing floor openings. The sixes luted for floor registers correspond to the standard sixes for gravity warm air furnace systems, except for the uses of the floor box collars. The use of standard blind boxes is suggested. A 12 x 51 in. stack may be used on Combination 45, and a 14 x 51 in. stack on Combination 46 with floor registers. in Tables 1 and 2. Tables 3 and 4'are also applicable for the selection of the return air branches. A depth of 8 in. has been adopted as the standard for the trunk ducts. The width of a trunk duct serving two branches is determined by adding to the width of the remote branch the value shown 'n column 8 of Table 1, or column 8 of Table 2. DESIGN PROCEDURE FOR LARGE SYSTEMS* For buildings having a heat loss in excess of 120,000 Btu per hour, the design procedure5 given in Manual 9 of the NWATI & ACA, may be used. Work sheets 9a, 9b, and 9c are available to simplify calculations.* The Procedure consists of: L Calculation of design heat losses from individual spaces in the structure. The filiation of these losses is explained in Chapter 12. V CHAPTER 20 1954 GuideiS Forced Warm Air Systems 467 i 2. Return Aik Duct System Combination op Parts Selected as '>' Standard . / " . .. ' - COMBI NATION No. Retubn-Aib Intake Rises Six, Size. In. I IIsn-. Weherkse Stack is Used in Stud Space Base. I FsoOK* BoAED ' ' Bbanch Pipe . Side. Ik- ' Requibed When Joibt Lining Inchease in w UaBDb'. - j Width op. . iTbunk Duct Numbeb of Joist Spaces Lined' and , Minimum Depth or (fob 8 In. > Depth or _ Duct), In. Space Required Run horizontally to left to obtain value for bonnet temperature in first column. Se lect 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 5 or 6 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 7 or 8 to obtain required free area and pressure loss of register. 7. Design nf duct system. .. . 51 10 X 6 6x10 10 x3V or 4 x 14 52 10 x 6 6 x 10 10 x 3i* or 4 x 14 53 12 x 6 6 x 12 12 x Si4 or 6 x 14 54 14 x 6 6 x 14 14 x 3Jd 4x8 a space of 3 in. depth 4x8 1 space of 3 in. adeeipth 5x8 1 space of 4 in. depth 1 space of 5 in. depth A. Warm air branches. ; . ; a. UseTable9 to select maximum bonnet pressure usually required for.the trunk carrying the maximum volume of air (cfm). If the maximum .. bonnet pressure is not high enough to accommodate the pressure loss .: ; ' through the registers, use a higher bonnet pressure. If the register pre ' sure 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 pressure loss, as \ determined from Tables 7 or 8, from maximum bonnet pressure. ; c. Obtain the pressure drop in each duct per 100 ft by use of Table 10. . > ; d. Determine duct size by means of air friction chart (such as Fig. l, Chapter 32), volume (cfm)> and pressure drop per 100 ft of duct. B. Return air branches. . . 55 24 x 6 6 x 30 or 30 x 6 56 30 x 6 6 x 30 57 8x30 1 space of 6 in. . depth or 2 spaces of 3 in. depth* l 10 .10 x 8 1 space of 7 in. , depth or 2 spaces] . o! 4 in. depth 12 15 x 8 1 space of 9 in. , depth or 2 spaces ... of 5 in. depth 7 12 a. Select a low value of actual duct loss obtained from step b under item A for the suction loss of return duct system. _ b. Proceed in sizing return air branches by the same method described for . 5 the warm air branches. Cr Trunk ducts for warm air and return air sides of system. 1 j a: Add air volumes of branches to be handled by each trunk duct. /, b. The friction loss per 100 ft of trunk duct is determined by taking the ; smaller of the two values for friction loss for the two ducts meeting at ; the junction. . 1 ...... . ' e. Determine trunk duct size by using an air friction chart, volume (cfm) . Vand pressure drop per 100 ft of trunk duct. . a Use these item__s_o_n_ly__w_h_en__b_u_ilding constructiIon., orespacities, require!/the, u:se, of floo- r intakes. 'The sizes listed correspond to standard sizes for gravity installations, except floor box collars. The use of standard 8. Selection of Blower. i; A. Determine total cfm air delivery (the sum of all branch cfm values). B. Determine static pressure requirement. , .. bmliunbmdBbdaoesxpeetdshoirsnesq1uu4giirgnee.dss,tpeinadc.we hbiecthwceaesne jaoidsrtos.p Use full depth o{ pan must be used. joist, This except when joist depth is less than suin' may occur when two or more return.ducto . avFor furnace-blower combination units it is the sum of bonnet pressure 'and suction pressure. - . areccIofninteicsteddestioretdhetosuasmee1j4oiins.txsp3afcien.'. stud space, it makes no difference whether this space has protruding -........ ;._b. For blowers separately selected from the furnace it is the sum of bonnet r nost.desired to use 14 in. x 3f in. stud. space`, the plaster b.a. se",must be smooth, wit.h.out any protruding - . pressure, suction pressure, filter, loss, casing loss, losses through air wash keys i ; Vers, coils, and other devices. d If it is desired to use is m. * . *. ----- -if plaster key--s to interfere with the flow of air. 2. Location of registers and return intakes on floor plan, showing types of registers, 9. Selection of Furnace. . A. Determine register delivery (the sum of room Btu losses). :i2t.* Locationfomf mregriesgteisrstearntuoroopi,upois*iteww_a__ll__a_n_d deflection of registers desired. with distance from register to opposite wall and * cirfog of B. Determine bonnet capacity. . Bonnet capacity = (total cfm) X (temperature rise) X 1.089. - tlleehnneogg.sstthnyy"ssss*tteeyoommiffn,,geeaaaao-nnc-c-uhdhd--timbbna-rrecaap,]lnnuroccdphhinogslliiennddeeedtffarruooiclsmmt osbnyf sootytnnepnnmeeeustfooti>orf\> fbriteotigtn-igstse.r.a.,nwd itthheouatctsuizaelsa. nd(SeeqeuiFvi*g. i^avv. Groups l throug'h 6* , f'or equ-ri--va*l*e**n**til/exnfrg+t.bh noffffiittttiinnegss..)) C. Determine allowance for pick-up load. For buildings which are heated in . , termittently, such as cnuTches and auditoriums, it ib customary to add from 10 to 25 percent extra furnace capacity for warming of the structure. en4tIe.frrDataetbitnelegrmsahitneatehttiiosfonvraofulufrenb.aocnenIf-ebtnlootwetmesrppeuecrnaifiitteusdrpe,e.ucsifeietshaeffixoelldowvainlugeporfobcoendnuerte: UsedaDi e5fonfrotebrru.b.ti.alu.d.b.i.il.ndl.e.ginsaghtsai'nhvnainsvgivnamghua~ecah. telaotsslo-gs--sreb~aretetwr etheann>132u50s0,e0,00t00h0eaBntotdun3op5we0,ri0uh0gr0. Btu per Sne.lief^ct s-hhhron*ort.tjer>s<TtiataabcctlteyyaMo' length and read downward in nearest column in Tables 5 or 6 until lower heavy_diage* nal line is reached, but do not cross line.'' VEttin horizontally to first column of tap . and note bonnet temperature: -Also select longest^actual length and read downwa in nearest column in Tables 5 or 6, until upper heavy diagonal line is just crosse AUTOMATIC CONTROLS ... A-ir stratification, high bonnet temperatures, excessive flue gas tempera- e|.res> and heat overrun or lag in a properly designed system, can be largely uninated through proper care in the planning and installation of the con- oi system;6 desirable controls usually employed are: . A thermostat located in occupied space-where maximum fluctuation in tempera- CHAPTER 20 Table 3. Capacity Tables for Warm Air and Return Air Branches*' *> . . FIRST STORY UNINSUL. ATED Actual Lehotb (fbom Bonnet to Boot) on, (reo Return Plenum to Boot) in *bet 1 to 7 FT. 3 TO 12 FT. 1 3 to 17 1 1 TO 24 FT. FT. 25 TO 34 S } to 44 FT. FT. 4 5 TO 54 FT. Warm Air Combi nation No. I ;etubw Air : = Combi- - nation No. Col. a Col. b Col. c Col. d Col. e Col. f Col. g Section A. 40 to 69 Equivalent Ft for Fit tings and Register 7200 12500 16000 19100 25000 32000 80000 6700 11700 15000 18000 23400 30000 75000 6100 10800 14000 17000 21600 28000 70000 5600 9900 13000 16000 19800 26000 65000 4800 8500 11300 14200 17000 22600 56500 4100 7400 9900 12500 14800 19800 49500 3500 6400 8700 11000 12800 17400 43500 .41 42 43 44 45* 46* 51 52 53 54 55 56 57" Section B. 70 to 99 Equivalent Feet 5500 9900 13100 16300 19800 26200 65500 5100 9200 12300 15400 18400 24600 61500 4800 8600 11600 14500 17200 23200 58000 4500 8100 10900 13700 16200 21800 54500 3900 7100 9700 12200 14200 19400 48500 3400 6200 8500 10800 12400 17000 42500 3000 5400 7500 9500 10800 15000 37500 41 42 43 44 45* 46" 51 52 53 54 55 56 57" Section C. 100 to 129 Equivalent Feet 4600 8500 11300 14300 17000 22600 56200 4300 7900 10600 13500 15800 21200 52600 4100 7400 10000 12700 14800 20000 50200 3800 6900 9400 11900 13800 18800 47300 3300 6100 8400 10500 12200 16800 42000 3000 5300 7400 9300 10600 14800 37000 2700 4700 6500 8300 9400 13000 32400 41 42 43 44 45" 46" 51 52 53 54 55 56' 57" Section D. 130 to 164 Equivalent Feet Section E. 165 to 200 Equivalent Feet 4100 7300 9800 12300 14600 19600 49200 3800 6500 8800 11000 13000 17600 44100 3800 6900 9100 11700 13800 18200 45800 3500 6100 8200 10500 12200 16400 41500 3600 6400 8600 11000 12800 17200 41900 3300 5700 7700 9900 11400 15400 38800 3400 6000 8100 10300 12000 16200 40300 3100 5400 7200 9300 10800 14400 36000 2900 5300 7200 9100 10600 14400 36000 2700 4800 6400 8300 9600 12800 32000 2600 4700 6400 8100 9600 12800 31800 2400 4300 5700 7300 8600 11400 28200 2300 4200 5600 7100 8400 11200 28100 2100 3800 5000 6400 7600 10000 24700 41 51 42 52 43 53 44 54 45" 55 46" 56 57" 41 51 42 52 43 53 44 54 45" 46" 55 56 * *_5_7_" Fob INSULATED Deem FT. 17 FT. Col. c 18 to 24 FT. Col. d 25 to 34 FT. Col. e 35 to 54 FT. For Deers that abb COM* PT.ETELY INSULATED WITH i In. Thick Ineu> USB these Column Heading * These tables are for use is sizing both the warm air and the return air branches. . - b Frictional resistances and temperature drops in ducts have both been accounted for in these tab!9* e Use these items only when the building construction, or capacity requirements, necessitate the u* two adjoining stacks or Boor registers. Forced Warm Air Systems 469 Table 4. Capacity Tables fob Warm Air and Return Air Branches*' *> SECOND STORY Fob ' UNINSU LATED Metal Deers <m.aoAi. Length (from bonnet to Boot) ob. (fbom Return Plenum to Boot) in Feet - 1 to 7 FT. 8 TO 12 FT. 13 TO 1 ' 18 To 2 FT. FT. - 25 to 3 FT. 35 to 4 1 45 to 5*l . FT. FT. Wabm Aib Combi nation Col. a Col. b Col, c ' Col. d Col. e Col . f Col. o Section A. 40 to 69 Equivalent Ft for : Fittings and Register 6300 10900 14000 17000 21800 28000 70000 5700 1 5200 10000 9200 13000 12100 15900 14900 20000 18400 26000 24200 65000 60500 4800 8500 11400 13900 17000 22400 57000 4100 7300 10000 12400 14600 20000 50000 3500 6400 8800 11100 3100 5600 7800 9900 12800 11200 17600 .15600 44000 39000 41 42 43 44 45" 46" Section B. 70 ta99 . Equivalent Feet 5000 9000 11900 14800 4600 8200 11000 13900 18000 -16400 23900 22000 59500 55000 4300 7600 10300 13000 15200 20600 51500 4000 7100 9600 12200 14200 19200 48000 3400 6200 8400 10800 12400 16800 42000 3000 5400 7500 9600 10800 15000 37500 2700 4700 6700 8500 9400 13400 33500 41 42 43 44 45" 46" Section C. 100 to 129 Equivalent Feet 4200 7700 10400 13000 15400 21700 52200 3900 7200 9700 12100 14400 19400 48400 .3700 6700 9000 .11300 13400 18000 45300 3500 6200 8400 10600 12400 16800 42300 3000 5400 7400 9400 10800 14800 37000 2600 4700 6500 8300 9400 13000 32500 2400 4100 5800 7400 8200 11600 29000 41 ' 42 43 44 45" 46" Section D. 130 to 164 Equivalent Feet 3800 6800 9100 11400 13600 18200 45500 3500 6300 8400 10500 12600 16800 42000 3200 5800 7900 9800 11600 15800 39600 3000 5500 7400 9200 11000 14800 36800 2700 4800 6300 8100 9m 12600 32200 2300 4200 5700 7200 8400 11400 28200 2100 3700 5000 6400 7400 10800 25100 41 42 43 44 45" 46" Section E. 165 to 200 Equivalent Feet 3500 6100 8200 10300 3200 5700 7600 9500 2900 5300 7100 8900 2700 5000 6700 8300 2500 4400 5700 7400 2100 3900 5100 6500 1900* 3400 4500 5800 41 42 43 44 12200 16400 41000 11400 15200 38300 10600 14200 35800 10000 13400 33400 8800 11400 29000 7800 10200 25800 6800 9000 22800 45" 46" Return Aib Combi nation No. 51 52 53 54 55 56 57" 51 52 53 54 55 56 57" 51 52 53 54 55 56 57" 51 52 53 54 55 56 57" 51 52 53 54 55 56 57" For Jnsulated Ducts Col. a l TO 8 Col. b 9 to 14 ft. Col. c 5 to 20 FT. Col. d ; 1 to 27 FT. Col. e 1 ft. Col. f ^ ob Ducts that are COM PLETELY INSULATED 3 TO 54 vriTH h In. Thick Insulati on rr. 'bom Bonnet to Boot Use rnESE Column Headings. k -- Mutes me ior use tn sizing both the warm air and the return air branches. Frictional resistance and temperature drops in ducts have both been accounted for in these tables. twn Adjoining sitteacmkss oonr lfyloworhreengitshtee.rbs.uilding construction, or capacity requirements, necessitate the use of 470 CHAPTER 20 Fig. 4. Equivalent Length oj-Fittings GROUP 1. WARM AAIiRr AND RETURN AIR BONNET OR PLENUM. 1954 Guide"' Forced Warm Air Systems Fr.c-. f- Equivalent Length of Fittings (Continued) GROUP 4. BOOT FITTINGS. FROM BRANCH TO .STACK. 471 (O. ft ELBOWS FOR TRUNK DUCTS; INHOE RADIUS '/2 WIDTH OF DUCT. GROUP 2. ANGLES AND 462I432ftt.TTTTTOOOOO I2455S1724--*-211250550**` 2345222345TTTTTOOOOO 234S57234I-*----3224S005O0.*"''' 2321|72f24t TTTTTTTOOOOOO03f02l24t1732-------tIISOZ43O0OS5****!' r y tai ft "! GROUP. 3. TRUNK DUCT TAKE-OFFS 30'cart 35'M.rx aBUP 5- STACR ANGLES. ELBOWS. AND COMBINATIONS % VeftVTT (0, . I0*fft. ft. W^WIOTH- 15 . tor WIDTH -40* ' lH- I * 1 12" . so* 14 " - 2Cf W- - . 55- ^, .. I *0 c* tt Ift'to. rt _ROUf> fi RETURN AIR ; .- J?it?J?*2*3*%5?h-""m7!0?-. *,fX Wt1*O22%**3334fWt--m8-8870335***' 10* t. rt 8d* n ture can be expected, in order to secure frequent operation of fans, drafts, and bur' ers. The thermostat location should not be on an outside wall, in a bedroom, batnroom, or sun room, or in a location where it will be affected by direct radiant heat from .A*0M*r` emu. and fitting, r.a. emu. to stud space, r.a. grill onlt. . TLOOR GRILL TO LINER *th?e? sun or from a fireplace, or by direct heat from any warm air duct, register or ca>rnney. . A/an sanfeh control to start blower operations at air temperatures between 110 130 F, and to stop the blower at about 15 deg below the cut-in point. The lower 472 CHAPTER 20 1954 Guide Fiol 4. Equivalent Length of Fittings (Concluded) GROUP 7. REGISTERS (INCLUDING LOSSES IN STACKHEAO AND VELOC.TY PRESSURE). DEFLECTION ANGLE 25 EQ. FT. FL. REG. A BOX ONLY Table 4A. Equivalent Length fob Registers Deflection Angle A Baseboard, High or Low Sidewall Registers_______________ Eq. Ft. 35 45 50 Floor Registers with Box only For 2-way deflection registers, add the vertical and horixontal deflection angles together and multiply by0.7. Select closest angle A in Table 4A. For diffuser type registers see manufactures' catalogs. . settings axe used for high sidewall register installations, and the higher settings for baseboard register installations. For most satisfactory results these settings should be 3a.sAlopwroatseicstifveeashiibglhe.limit control to stop the how of fuel to the burner independ- . ently of the thermostat if the air temperature exceeds 175 F. 4. Oh oil and gas burner installations, a protective control should be included to cut off the fuel supply if the fire is extinguished, or if there is a failure of the igni tion system. . .' 5. On automatic stoker installations, a control is usually included to operate the., stoker regardless of thermostat settings whenever the bonnet temperature indicates he fire is dying, or a time interval contactor is used to cause the stoker t`o---r-u--n- --a that the .....j...,,, . _ ._ few minutes out of each hour. 6. A humidistat to regulate the moisture supplied to the rooms, located either in one of the rooms or in the main return duct near the furnace. . , . -j ADJUSTMENT OF SYSTEM FOR CONTINUOUS AIR CIRCULATION j This procedure applies to the adjustment of an automatically-fired forced ; warm air heating system to provide continuous air circulation, when the . control arrangement is of the type where the room thermostat controls the fire, and the blower control (fan switch) controls the blower operation. [ This procedure as outlined in detail in Manual 6 of the National Warm. Air * Healing and Air Conditioning Association, is as follows:7 ; 1. Adjust the fuel input in proper relation to the heat loss of the structure, rfl", . 2. Determine the temperature rise through the furnace. -Li H 3. Adjust the air volume to produce a temperature rise through the furnace of7 'j about 100 deg. ; 4. Adjust the fan switch differential to a minimum of about 15 deg. ': 5. Adjust the fan switch cut-out point as low as practicable. , 6. Adjust the room thermostat temperature differential to a minimum which will, cause the burner to cycle frequently. 7. Balance the system by adjusting dampers to produce even temperature distn-' bution between rooms. Q tho rnnm iViaprnnflfftt, At. the desired amnoFfttlirfi. - Forced Warm Air Systems 87 1 42.7 106 105 I 103 1 102 , 101 l 24.2 24.8, 26.0 26.6 27.3. 100 99 98 97 28.0 28.8 29.6 30.5 1 230 c <C e . 0co0 CO 2! C^O 90 38.1: 93 34.6 0'83 , 001 3-- 1O0l 95 32.3 37.3! 93 - 9 2 91 OZZ | (C F M ) | 200 89 ) 39.! 883 o <N C005 0C3O 02oCoO -*t CCOO : 34.e 1 3 5 .S1 29.6 WCO 30.5 eo --i0^4 107 106 105 103 102 23.6 24.2 24.8 26.0 26.6 28.8 101 99 98 97 y T83 801 r e 90 1 38.( I 112 n o 21.l| 22. l! 102 i 26.6 104 : 25.4 101 100 99 98 97 27.31 28 C1. 28.8t 29. ie 30.J L in ear D istance from B o nnet to R eg ister, in F e e t . v i l e )D . eHrr /t isU gT g 0C4O I 170 ) 0*-5< eCo*. OCO 0045 CO ~CHO 27.3 t---1 20C4O "0044 110 22.1 I 130 1 118 18.4j Register D elivery Volume in C F M per 1000 B T U per H r. 0RBe and 5 0 ,0 0 ture an'd 8 empera IS O ,000 1 150 0e5o-C*O* i= -059* CCOO oeho04 '"0.044 ister T between ! 801 *0o5cCmO' r-- coco -- 0C4O 04 ^04 VP-5? as 124 122 1 17.3 17.9, 122 120 118 116 17,9 18.4 19:o 19.6 106 105 T03 102i 2 4 . !( 24.8: 26 C1. 26.6i n o 108 22.1 23.1 97 1 30. reg Loss I no hatube, a Heat jass imnvge 00 <0N5 e 0055 0040 CO ^ 04 CO ^ aa B2 131 129 1 15.71 16.2j 1 108 > 23.1 117 19.3 101 100 i 27 J1. 28.( Bx B u ild in g s No lO as (For COO 04. St; 7 aar wb 139 7 14.2 CJ* CO CO 136 --133 -- 14.8 15.3 143 140 13.5 14.0 '1 130 15.9 137 14.6 128 16.4 134 15.1 126 16.9 131 15.7 123 17.6 128 16.4 121 18.1 126 16.9 119 18.7 124 17.3 117 1 115 19.3 20.0 122 120 17.9 18.4 113 112 110 20.7 21.1 22.1 ------- L 118 116 114 19.0 19.6 20.3 107 106 23.6 24.2 n o 109 107 22.1 22.5 23.6 103 26.0 106 24.2 112 21.1 153 12.2 150 12.6 146 13.1 143 13.5 140 14.0 137 14.6 135 14.9 131 15.7 126 124 122 120 118 16.9 17.3 17.9 18.4 19.0 115 | 20.0 U , 110 21.6 22.1 - 160 11.4 156 11.8 1116.3l | 149 12.7 145 13.2 151 12.4 142 13.7 147 12.9 136 14.7 144 13.4. 133 15.3 138 14.4 130 15.9 135 14.9 li1.58a j 128 16.4 132 15.5 126 --124 -121 119 16.9 17.3 18.1 18.7 ------- 129 127 125 16.2 16.6 17,2 117 19.3 120 18.4 115 20.0 118 19.0 L 113 112 20.7 21.1 116 19.6 473 1 -c" las CO ^ f"a1s'0. 0044 0QO4^ <o*1w* oCO.H'V \ CO0044 ^1 22 a= value in each *J 474 CHAPTER 20 1954 Guide 14.9 15.9 135 130 14.2 14.6 15.3 18.6 1 4 .0 1 4 .4 14.8 15.1 15.5 15.9 16.4 16.6 17.3 139 137 133 127 15.5 15.9 16.4 ,16.6 16.9 |17.2 17.3 17.6 18.1 140 138 136 134 132 130 128 127 124 ' 132 130 128 127 126 125 124 123 121 18.4 18.7 ;i9 .o 19.3 19.6 120 119 118 j 5 s 12 n 0.0 5 S5 1 ^-- ^c* 5 il m fi I eo | j ss d cdr-O4 d cS *--C f-4 to H CI-O"* 1"o4 O<r-S04* OdHS dt*DH 1c-o4 s*-Ho r-* co so 117 116 20.7 21.1 21.6 113 112 111 200 210 220 15 d co i 00 =? w___ cdo t><.0 C-Ol r-*4** se^oo OS S 3 12.7 12.9 13.4 16.6 16.9 17.2 17.6 18.4 128 j 127 126 125 123 120 150 160 j 170 1 913 5-t I oy-s4 CrO- * d <0 rO-as! m NfH eo K___ 2 Nw ro*s 19.0 118 *ls S 5 c3 co 5 os c3___ <d eOpo4 >*i CO os o <e4--0o4 1 * 0 O1*"O** ^ f^H eo ccs SO CO * F"4 d . ^ OS fCO4 SO co CO so 655 ci S w* 149 147 CO T#4 CO S' d d 14.4 15.3 16.2 16.6 138 136 134 132 |14.4 |14.8 Il5 .1 16.5 138 11.5 11.8 12.9 159 156 133 129 127 17.2 17.3 17.6 90 100 j 125 124 123 3$! ! d CO 3___ 2 ^ eo ri dK r4 g O ~~d S ^ 147 s^ *4 y-N so d y-H *--4 co SO eo OSO dCO* ' 23 IICO -4 a -3 1 jd 11 CO C* cd so CO 1** so s*os <r+ dC--O4 8 O S( y^-l 5 Os U5 d >0 OS c-*o* SO eo O *0___ d OsoO tO~ " S>*O> C4 CO dto deo CO co C_D 00 Ci~OS t-O4 . <=? d d ^Os D d CD TH C--O4 HO cO _ c os O 10.3 CO --4 Ct"D ooss-. 10.7 172 1 6 .4 1 6 .6 60 j 70 128 127 lie s <=1>(^0 0sO4 OCrHOs d ' S y* os 2 S 0 d1--4. sy--4 0 ---4 d *f->H- CO OH o*t-s4- O0S0` Os CO 0lO-0* t--o-4*< s to 0t- N ^ O ii O co *0 eTfo SeOo CO so tD e-t g 0 r0-0 dOs- 0N I W< ^ co CO d CIsO* 0 HO o1-*s* OS 40 132 15.5 158 155 152 150 ! 11.6 1 2 .0 1 2 .3 1 2 .6 167 1164 10.7 11.0 177 9 .9 182 j1U78| 9.6 183 9 .5 D CCOO ^* tp C-*O* d00 S8 ^-4 <D 03 ar- 00 OO f, b Ms 0 H 5^ U * 2 0 150 12.6 160 11.4 170 10.5 180 9 .7 200 8 .6 as os && Table 7. Determination op Free Aru. -r r. fob 22 Deo Deflection If tek*TM*8TM* Loss OP Register DistanOceppFohsoitme HWa^de^t^to 31-.34 35~39|40-49JSO-59^60-69)70-79 S * Jj . A B ------------------------------------------ 319 0.04 230 0.06 163 0.12 136 0.2) 338 244 m | 122 0.03 O.Ofi 0.11, 0:20 356 256 IS2 i 129 0u.-0w3 0v.u0o6 0.10 0.19 ""'l^KaT (8tat,C plUS Velocity) '<* based on FLAT MCE A`"o *" ^alueaD right of line Band B'sh m *1^ PP cations such as churches, auditoriums, and con *tp" .^ TZ--T- f^ Wed 'D aP*-P-'iCati0na SUCh " icftiuenuai work, mmoottiioon picture the.- y> 2 Assume a pressure loss of 0.01 CFM X 144 300 476 CHAPTER 20 1954 Guide Table 8. Determination of Free Area and Total Pressure Loss of Register for No Deflection of Air h'c> B ' Register Free Air in Square Inches (Upper value, in each group) Pressure Loss in Inches of Water Column (Lower value in each group) ottu I Distance raou Heobteb to Offositt Wall >TBTANCE FROM . . _____________ ____ _ ... ri22^4i2^7[28^l31-34| 35-39 CFJf | DiaTAmEjraoM^RMMTAB to . ............................. Ur_MiAft-^o1 Kft-R6 160-69170-79 180-89 ------- j------ 7] ^ 1 j >00-539 >40-579 >80-619 120-659 * If register selected based on distance from register to oppo-; te wall is unsatisfactory on account of size or pressure loss, it is jrmis-rible to shift one or more spaces left or right in the tables > obtain a more suitable register. If requirements fall in blank pace, select two registers in place of one and divide CFM capac- ,y between the two registers. : b Total oressure (static plus velocity) loss is based on FLAT ACE ADJUSTABLE BAR TYPE and does NOT include tackhead. c Value? on the right of line A and A'ahould not be used inap* dications such as churches, auditoriums, and concert halls. d Values on right of line B and B' should not be used in ap plications such as residential work, motion picture theaters, court rooms and schools. ' * For floor and baseboard registers where a velocity of ap proximately 300 FPM is used, the free area = or ap proximately, ---- Assume a pressure loss of .01, r *-> . Forced Warm Air Systems 477. Table 9. Suggested Bonnet Pressure Inches of water Total CFM Through Any One Duct 800-1000 1000-1200 1200-1800 1800-2400 2400 to 3500 Suggested Bonnet Pressure In. Water 0.10 0.10 0.10 0.13 0.14 Total CFM Trhouoh Any One Duct 3500 to 5000 5000 to 7500 7500 to 10,000 10,000 to 12,000 12,000 to 14,000 Suggested Bonnet Pressure In. Water 0.15 0.25 0.375 0.500 0.750 WARM AIR CEILING PANEL SYSTEMS Warm air ceiling panel heating systems utilize a false ceiling suspended 3>4 in- from the ceiling joists which have previously been covered on the bottom with sheets of plasterboard. 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 fi in., making a completely sealed air space above the ceiling. Warm air is delivered'to this sealed spacethrough a standard warm air duct, installed in the usual manner: The air is then circulated over the entire ceiling being guided by sheet-metal baffles. After the air has passed over the ceding,' it is returned to the fur nace 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 24, Panel Heating.) Because a warm air ceiling panel system involves a different type of ceiling construction, its installation is practically limited to new construc tion. Only automatically-fired and thermostatically-controlled furnaceblower units may be used with this system. The standard automatic heating controls consisting of a room thermostat, temperature limit con trol, blower control (fan switch), and primary control are all that are re quired. 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 houses with basements. Complete design and installation procedure is given8 in Manual 7-A of the National Warm Air Healing and Air Conditioning Association. WARM AIR PERIMETER SYSTEMS Perimeter heating is a method of heating residential and commercial buildings, with or without basements, in which warm air is (a) conveyed under the floor to warm the floor surface and (b) introduced into the rooms, preferably under the windows, at or near the floor, and delivered upward in diffused pattern blanketing the outside walls. The return air is collected through one or more grilles located high on the interior sidewalls or in the ceiling. Suggested procedures9 for the design and installation of warm air Perimeter heating systems are given in Manuals 4 and 10 and in the ac companying work sheets10 of the National Warm, Air Heating and Air Con ditioning Association. The furnace may be either the down-flow or the conventional up-flow type. For basement-less houses the down-flow type is preferred since it requires a minimum amount of floor area and ductwork, and eliminates 478 CHAPTER 20 1954 Guide Table 10. Pressure Drop in Duct Inches of Water per 100 Feet of Duct Length Equiva lent Length of| Duct (Ft) 0.04 J.05 ).06 9.0? Total Pbessubb Drop in Duct (In. of Water) L08 9,09 ).~10 0. 0.12 ).13 (). 14 ().15 (9.16 0 35-44 45-54 55-64 65-74 75-84 85-94 95-104 105-114 115-129 130-149 150-109 170-189 190-214 215-239 : 240-264 265-289 290-324 . 325-374 375-424 425-474 T 475-524 525-574 575-625 0.10 0.08 0:07 0.13 0.10 0.08 0.15 9.12 9.10 0.18 9.14 9.12 0.20 9.16 3.13 0.23 9.18 9.15 0.25 0.20 0.17 0 0 0 0.06 0.07 0.09 0.10 0.11 0.13 0.14 0 0.30 0.33 0.35 0.38 0.40 0 0.24 0.26 9.28 9-30 9.32 0 0.20 0.22 9.23 0.25 0.27 C 0.17 0.19 0.20 0.21 0.23 0 0.05 0.05 0.04 0.06 0.06 0.05 0.08 0.07 0.06 0.09 0.08 0.07 0.10 0.09 0.08 0.11 0.10 0.09 6.13 0.11 0.10 0 0 0 0.04 0.05 0.05 0.06 0.07 0.08 0.09 0 0.15 0.16 0.18 0.19 0.20 0 0.13 0.14 0.16 0.17 0.18 ( 0.12 0.13 0.14 0.15 0.16 ( 0.11 0.12 0.13 0.14 0.15 0 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 0.04 0.04 0.07 0.06 0.05 0.04 0.08 0.07 0.06 U.05 0.08 0.07 0.06 0.06 0 0 0 0 0.10 0.11 0.12 0.12 0.13 C 0.09 0.09 0.10 0.11 0.11 1 0.08 0 08 0.09 0.09 0.10 G 0.07 0.07 0.08 0.08 0.09 C 0.02 0.03 0.03 0.04 0.04 0.05 0.05 G 0.02 0.02 0.03 0.03 0.04 0.04 0.05 C 0.02 0.02 0.02 0.03 0.03 0.04 0.04 ( 0.01 0.02 0.02 0.03 0:03 0.03 0.04 ( 0.06 0.07 0.07 0.08 0.08 ( 0.05 0.06 0.06 0.07 0.07 ( 0.05 0.05 0.06 0.06 0.06 ( 0.04 0.05 0.05 0.05 0.06 ( 0.01 0.01 0.01 0.01 0.02 0.02 0.01 0.01 0.02 0.02 0.02 0.01 0.03 0.02 0.02 0.02 0.03 0.02 0.02 0.02 0.03 0.03 0.02 0.02 0.03 0.03 0.03 0.03 (0.04 (0.03 0.03 0.04 0.03 0.03 0.03 0.04 0.04 0.03 0.03 0.05 0.04 0.04 0.03 0.05 0.04 0.U4 0.03 0.05 0.05 0.04 0.04 0.01 0.01 0.01 0.02 0.02 0.02 0.02 0.01 0.01 0.01 0.01 0.02 0.02 0.02 0.01 0.01 0.01 0.01 0.01 0.02 0.02 0.02 0.03 0.03 0.03 0.03 0-02 0.02 0.03 0.03 0.03 0.02 0.02 .02 0.03 0.03 Equiva lent F ) 0.21 0.22 0.23 0.24 Total Pressure 0.25 0.26 0.27 35-44 45-64 55-64 65-74 75-84 85-94 95^104 .105-114 115-129 130-149 150-169 170-189 190-214 215-239 240-264 265-289 290-324 325-374 375-424 425-474 475-524 525-574 575-625 0.53 0.42 0.55 0.44 0.58 0.46 0.60 0.4$ 0.63 0.51 0.65 0.52 0.68 0.54 0.35 0.35 0.31 0.41 0.42 0.4c 0.45 0.30 0.32 0.33 0.34 0.36 0.37 0.39 0.26 0.28 0 29 0.30 0.31 0.33 0.34 0.23 0.25 0.21 0.2: 0.21 0.29 0.30 0.21 0.22 0.2: 0.2' 0.24 0.21 0.27 0.19 0.20 0-21 0.22 0.23 0.24 0.25 0.1 0.15 0.12 0.1$ o.n 0.1 0.15 0.1' O.r 0.2C 0.1 0.K 0.21 0.1! 0.1' 0.25 0.1 0.1 0-23 0.19 0.17 0.15 0.15 0.1 O.U 0.1 0.1 0.15 0.1 0.1 o.i 0.1 0.1 0.1 0.14 0.0<) 0.1 1 0.1 0.1 0.1 0.1 0.12 0.0 i 0.0 3 0.0 0-0 3 0.0< 0.0 3 0.1 0.0 ) 0.1 0.0 i 0.1 0.1 ) 0.11 0.10 0.0 7 0.0 6 0.0 1 0.0 i 0.0 3 0.0 0.0 3 0.0 0.0 3 O.U 0.0<) 0.0 i 0.09 0.08 0.0 5 0.0 t 0 (1 ) 0.0 ) o.o 0.0 7 0.07 0.0.5 0.0 5 0.0 5 0.0.5 0.0 3 O.W5 0.06 0.04 0.04 0.05 0.05 0.05 0.05 0.05 0.04 0.0 4 0.0 [ o.c 1 0.0 5 0.(3 5 0.05 0.04 0.04 0.04 0.04 0.04 0.04 0.05 HOP IN Duct (In. of Water) 0.29 0.30 0.32 0.34 0.36 \ ) 0.73 0.75 0.80 0.85 0.90 5 0.51 0.6( 0.64 0.61 0-72 7 0.41 0.5C 0.5c 0.57 0.60 9 0.42 0.43 0.46 0.49 0.52 5 0.36 0 38 0.40 0.43 0.45 1 0.32 0.3! 0.31 0.31 0.40 8 0.2? 0.30 0.32 0.3: 0.36 6 0.2? 0.28 0.29 0.31 0.33 3 0.24 0.24 0.2' 0.2$ 0.30 0 0.2 0.2 0.2a 0.24 0.26 8 0.1 o.r 0.2i 0.2 0.23 6 0.1 o.r 0.1 0.11 0.20 4 0.1 O.U 3 0.1 1 0.1 1 0.1 2 0.1 0 0.1 0.1 0.1 o.r 0.1 0.1 0.1 : o.l 0.1 t 0.1 0.18 0.16 0.15 0.13 >9 0.1 9 0.1 9 0.1 1 0.1 l 0.12 8 0.019 0.0 } 0.0 i 0.1 i 0.10 7 0-0 B 0.0 9 0.0 5 0.0 9 0 09 6 0.07 0.0 7 0.0 7 0.0 8 0.08 )6 0.06 0.06 0.06 0.07 0.07 )5 0.05 0-0 i O.C 1 0.07 0.07 15 0.05 0.05 O.U5 0.06 0.06 0.18 ( .19 0 0.45 0.48 0 0.36 9.38 C 0.30 9.32 ( 0.2- 0.28 0 0.23 0.24 0 0.20 0.21 ( 0.18 0.19 ( 0.16 0.17 C 0.15 0.16 C 0.13 0.14 i 0.11 0.12 i 0.10 O.U ( 0-09 0.10 0.08 0.09 0-07 0.08 0.07 0.07 0.06 0.06 0.05 0.05 0.05 0.05 0.04 0.04 0.04 0.04 0.04 0.03 0.03 0.04 0.03 0.03 0.03 0.40 0.45 1.00 1.13 1.25 0.8C 0.90 1.00 0,67 0.75 0.83 0.57 0.64 0.73 .0.50 0.56 0.63 > 0.45 0-50 0.56 5 0.4( 0.45 0.50 5 0.37 0.41 0.46 2 0.33 0.38 0.47 7 0.21 0.32 0.36 4 0.25 0.28 0.31 1 0.22 0.25 0.28 9 0.2C 0.23 7 0.1! 5 0.1 0.20 0.22 0.18 0.20 4 0.K 0.16 0.18 3 0.1 ) 0.15 0.17 1 9 0.1 0.1 i 0.13 o.n 0.14 0.13 9 0.0* 0.10 o.n 8 7 6 0.0 B 0.0 0.0 0.09 0.08 0.08 o.io 0.09 0-08 the need for a duct to bring the warm air down from the top of the furnace, or a duct to bring the return air down to the blower inlet. Several arrangements of perimeter ducts may be used to heat slabs on ground construction, but the most common is the type having a complete loop of a continuous duct around the edge of the slab, supplied by radial feeders extending from the furnace sub-floor plenum to the perimeter duct. A schematic cross-section of the slab construction, with the perimeter duct installed, is shown in Fig. 5. . The slab should be constructed on a well-drained site where drainage . Forced Warm Air Systems 479 away from the slab, and where there is no standing water at aiiy time of > the year. With slab construction, a suitable porous fill and a waterproof membrane as a moisture barrier beneath the slab are required by the Federal Housing Administration. They are highly necessary with warm air perimeter heating. Insulation must be placed between the edge of the slab and the foundation, and must extend completely around the slab to reduce the-heat losses from the edge of the slab. Fig. 5 also shows many of the essential features of the slab and under-slab construction. COOLING METHODS A slight cooling effect may be obtained under certain conditions by the circulation of basement air. A more positive cooling effect may be obtained by the use of an air washer where the temperature of the city or well water is sufficiently low (55 F or lower), and where a sufficient volume of water can be provided. Unless the temperature of the leaving water is below the Fig. 5. Cross-section of Slab Construction Containing Perimeter Duct* dew-point temperature of the indoor air at the time the washer is started, both the relative and absolute humidities will be somewhat increased. Coils of copper finned tubing through which eold water is pumped are available for cooling. They require less space than air washers, and have the advantage that no moisture is added to the air when the temperature of the water rises above the dew-point. Ample coil surface and fan capacity are necessary with this type of cooling. It is thoroughly feasible to use ice or mechanical refrigeration in connec tion with a warm air system and to cool the building by this method, pro vided the building is reasonably well constructed and insulated. Windows Mid doors should be tight, and awnings should be supplied on the sunny side of the building. See also Chapters 30, 37 and 38. . Conclusions drawn from studies" conducted in the University of Illinois Research Residence, subject to the limitations of the test are: , T An uninsulated building of ordinary residential type may require the equivalent "L^hree tons of ice in 24 hr on days when the maximum outdoor temperature reaches luu F, if an effective temperature of approximately 72 ET is maintained indoors. . 2. The use of awnings at all windows in east, south, and west exposures may result m Savings of from 20 to 30 percent in the required cooling load. 480 CHAPTER 20 1954 Guide 3. The cooling load per degree difference in temperature is not constant, but in creases as the outdoor temperature increases. f ' 4. The heat lag of the building complicates the estimation of the cooling load under any specified conditions and makes such estimates, based on the usual methods of computation, of doubtful value. . 5. The seasonal cooling requirements are extremely variable from year to year, and the ratio between the degree-hours of any two.seasons occurring within a 10-year period may be as high as 7.5 to 1. Hence, an average value of the degree-hours cool ing per season is comparatively meaningless. ' 6. The duct system in a forced-air heating installation can be successfully con verted to a system for conveying cool air for the purpose of cooling the structure. No condensation of moisture was observed when the duct temperatures were not less than 65 F. 7. Cooling by means of water at a temperature of 60 F is not satisfactory unless an indoor temperature of less than 80 F is maintained. 8. In the selection of cooling coils, the additional frictional resistance of the coil to flow of air must be given consideration. 9. Cooling the structure by introducing large quantities of outdoor air at night tended to. reduce the amount of cooling required on the following day, and was a practical means of providing more comfortable conditions in those homes where cool ing systems were not available. REFERENCES 1 A Yardstick for the Evaluation of a Forced Warm Air Heating System (National Warm Air Healing and Air Conditioning Association, Manual 8,. 1941). 3 Performance of a Forced Warm-Air Heating System as Affected by Changes in Volume and Temperature of Air Recirculated, by A. P. Kratz and S. Konzo (A.S.H.V.E. Transactions, Vol, 48, 1942, p. 393). 3 Code and Manual for the Design and Installation of Warm Air Winter Air Con ditioning Systems (National Worm Air Heating and Air Conditioning Association, Manual 7, Third Edition, 1950). 3 Proposed Design Procedure for Large Mechanical Warm Air Heating Systems, by S. Konzo, R. J. Martin, D. S. Levinson, and R. W. Roose (A.S.H.V.E. Trans actions, Vol. 53,1947, p. 177). . s Code and Manual for the Design and Installation of Large Warm Air Winter Air Conditioning Systems (National Warm Air Heating and Air Conditioning Association, Manual 9, Fourth Edition, 1950). . Automatic Controls for Forced-Air Heating Systems, by S. Konzo and A. F. Hubbard (A.S.H.V.E. Transactions, Vol. 40,1934, p. 37). 7 Service Manual for Continuous Air Circulation Technicians (National Warm Air Heating and Air Conditioning Association, Manual 6, First Edition, 1947). 3 Code and Manual for the Design and Installation of Warm Air Ceiling Panel Systems (National Warm Air Heating and Air Conditioning Association, Manual 7-A, ThsirWd aErdmit-iAonir P19e5r0im).eter Heating (National Warm Air Heating and Air Conditioning Ass10oWciaotrioknS, hMeaetnsufaolr 4W, aSremco-AndirEPdeirtiimone,te1r9S5y0s).tems (National Warm Air Heating and Air Conditioning Association, Forms 41a, 41b, 42, 43 and 45. 11 Summer Cooling in the Research Residence, by A. P. Kratz, S. Konzo, M. K. Fahnestock and E. L. Broderick (University of Illinois Engineering Experiment Sta tion Bulletins Nos. 290, 305 and 321). A.S.H.V.E. Research Refort No. 1177-- Summer Cooling in the Research Residence with a Gas-Fired Dehydration Cooling Unit, by A. P. Kratz, S. Konzo and E. L. Broderick (A.S.H.V.E. Transactions, Vol. 47, 1941, p. 203). CHAPTER 21 STEAM HEATING SYSTEMS Classification, of Steam Heating Systems by Types; One-pipe; Two-pipe,. Sub-atmospheric and Orifice Systems; Sizing Piping for Steam Heating.... Systems; Pressure Reducing Valves; Boiler Connections; Condensate Return Pumps; Vacuum Heating Pumps; Traps; Drips; Con- . nections to 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. 1. By Piping Arrangement. A steam heating system is known as a one-pipe system when 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- . A steam heating system is known as a two-pipe system when each heating unit is provided with two piping connections, and when steam and condensate flow in sepa rate mains and branches. . Heating systems may also be described as up-flow or down-flow, depending on 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 con densate receiver. 2. By Pressure or Vacuum Conditions. Steam heating systems may also be classi fied as high pressure, low pressure, vapor, and vacuum systems, depending 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 vapor system when the system operates under both vacuum and low pressure condi tions without the use of a vacuum pump; and as a vacuum system when the system operates under vacuum and low pressure conditions with the use of vacuum pump. When automatic controls are employed to vary the pressure conditions ini the sys tem 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. 3. 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 heat- mg units must be elevated sufficiently above the water 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-return fohh a U-shaped container, with the boiler steam pressure on the top of the water at one end, and the steam main pressure on the top of the water at the other end. The difference between these two pressures is the pressure drop in the system, i.e., 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 condensation occurring in the system, the water in the far end will rise sufficiently to overcome this difference in order to Paiance the pressures, and it will rise far enough to produce a flow through the return P*pe and overcome the resistance of check valves, if installed. " . If a one-pipe steam system is designed, for example, for a total pressure drop of $ Pci, and utilizes a Hartford return connection instead of a check valve on the return, 481 ' 482 CHAPTER 21 1954 Guide the rise in the water level at the far end of the return, due to the difference in steam pressure, would be $ of 28 in. (28 in. head being equal to one pound per square inch), or 3 in. Adding 3 in. to overcome the resistance of the return mainland 6 in. as a factor of safety for heating up, give's 12$ 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 $ psi, and with a check in the return, would require \ of 28 in., or 14 in. for the difference in Bteam pressure, 3 in. for the flow through the return, 4 in. to operate the check, 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 accordingly. When conditions are such that condensate cannot be returned to the boiler by the action of gravity, arid either traps or pumps must be employed, the system is knowD as a mechanical return system. There are three general types of mechanical con densate return devices in common use: (a) the.alternating return trap, (6) the con* densate return pump, and (c) the vacuum return pump. In systems where pressure conditions in the system vary between that of a gravity *etum and a forced return system, a boiler return trap or alternating receiver is employed and the Bystem may be known as alternating return system. When condensate is pumped to the boiler under pressures of the atmosphere or above, the system is known as a condensate pumpretum system. .* Steam Heating Systems 483 Steam pressure at 8oiter steam pressure end of main j-fiW . ` Return water ^--Water line of boiler.- *-'Rise*water line difference __ Lewi -- Jet r'turn -- T7T777777rrtT77777TT77r7 /777fr7? Fig. 1. Difference in Steam Pressure on Water in Boiler and at End of Steam Main Fig. 2. Typical Two-Pipe Connections to Unit Heaters in One-Pipe Air Vent Systems When condensate is pumped to the boiler under vacuum conditions, the system is known as a vacuum pump return system. . In either the condensate or vacuum pump systems it is highly desirable to arrange for gravity flow 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. Radiators and other heating units, in general, have only one piping 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 separate connec tions to the wet-return. . There are several variations in the piping arrangement of a one-pip system as follows: 1. Up-feed one-pipe systems where the radiators and other heating units are I" cated.above the supply mains. The mains in this instance convey both steam and condensate. Such a system is illustrated in Fig. 3. Typical connections to radiator or risers are illustrated in Fig. 4, and method of changing sizes of mains in Fig- 5 2. Up-feed one-pipe systems where the radiators and other heating units are Id" cated above the mains, and the mains are dripped at each radiator connection to a wet- return, so that the steam main carries a minimum of the condensate. This system is illustrated in Fig. 6. Typical connections to radiators and risers are illustrated in Fig. 7. Up-feed systems are not recommended for systems higher than four stories. 3. Down-feed one-pipe systems, where the radiators and other heating units are located below the supply main. In this 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. Each radiator or heating unit in a one-pipe system must be supplied with a thermostatic air valve which functions to relieve air from the heat ing unit under pressure, and to close when steam itself heats the thermo static element of the valve. ,. To improve steam circulation in one-pipe systems quick-vent air valves should be provided at the ends and at intermediate points where the steam main is brought to a higher elevation, or where dropped below the water line. It is desirable to install the air-vent valves about a foot ahead of the drips, as indicated in Fig. 6, to prevent possible 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 condi tions in the system, and a consequent evaporation or generation of steam Fig. 4. Typical Steam Runout where Risers Are Not Dripped Fig. 5. Method of Changing Size of Steam Main when Runouts . are Taken from Top 484 CHAPTER 21 1954 Guide Fig. 6. Typical Up-Feed Gravity One-Pipe Air-Vent System or vapor at sub-atmospheric pressures, and at consequent lower tempera- _ tures. Systems which use vacuum valves are known as vapor or vacuum one-pipe systems. The vapor or vacuum systems will maintain a mors . uniform temperature condition than the pressure systems. ., Each heating unit in a one-pipe system may also be provided with;a valve on the connection to the unit, although this is not essential except to shut the unit off in case it is not desired for heating. Valves on one- . pipe systems must be either fully opened or fully closed. No throttling . or inodulating position can be maintained since, if a valve is partially . closed^ condensate will not drain from the unit. This condition is dan gerous because it may create a low water condition in the boiler with con sequent burning or cracking of the boiler, or create a hazard due to the freezing of the water-legged heating unit itself. : - TWO-PIPE SYSTEMS . 'll Two-pipe systems, as previously defined, are systems in which steafi and condensate flow in separate pipes. Two-pipe 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; Fig. 7. Typical Steam Runout where Risers are Dripped Steam Heating Systems 485 Two-Pipe High Pressure Systems Two-pipe high pressure systems operate at pressures above 15 psig, usually from 30 to 150 psig. They are usually used in large industrial type buildings, which are equipped with unit heaters or large built-up fan units, or in which high pressure steam is required for process work. Fig. 8 illustrates a typical high pressure system. Because Of the high pressures and the great differential between steam and return mains, it is possible 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 economizer heater before being dis charged to a vented receiver. It is, of course, necessary to provide for the elimination of air from high pressure systems, the same as in low pressure systems. .- FROM HIGH PRESSURE BOILER r GATE VALVE- PIPE COIL FLOAT TRAP IECK VALVE --GATE VALVE \ 'I'1--i-------\tF" ECONOMIZER Vfc L . DRIP VENT-*. ---TO BOILER NHNNEO `FLOAT TRAP \ 'CHECK VALVE RECEIVER RADIATOR , Fig. 8. Typical High Pressure Heating System . Return traps used on high pressure systems are usually of the bucket, inverted bucket, float or impulse type. Two-Pipe Low Pressure Systems Low pressure systems operate at pressures of 0 to 15 psig. The piping arrangement of both up-feed and down-feed low pressure systems is iden tical with those of two-pipe vapor systems described in the following sec tion. 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 system cannot operate under a vacuum. The low pressure systems are not as popular as the vapor sysems> because they have the disadvantage of hot holding heat when the rate of steam generation is diminishing. They also have the disadvantage i corroding to a greater extent than vapor systems, due to the continued Presence of new air in the system. Low pressure systems have the advantage, however, of 'returning conensate to the boiler readily and not retaining it in the piping, as may be possible in vapor systems when the system pressure exceeds the operating Steam Heating Systems 487 By-pass to drain Fig! 9. Typical Installation Using Condensate PiImp range of the average vapor system. Fig. 9 illustrates a typical low pressure 5- system with condensate pump. - Two-Pipe Vapor Systems n;f.- 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 psig without the use of a vacuum pump... A typical two-pipe up-feed vapor system is shown in Fig. 10, and a typical two-pipe down-feed system ^ is illustrated in Fig. 11. The method of dripping drop risers in a down-feed^? system is illustrated in Fig. 12. Radiators 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 return mains just before they drop to the wet return. The vent valves are of the float and thermostatic type which opens when cool air contracts the thermo static element, and closes when steam expands the element: 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 disc 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, depending on the tightness of the system. . Vapor systems may also be provided with an automatic return trap or alternating receiver which automatically returns 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 auto matic return trap are illustrated in Fig. 13. Fig. 10. Typical Up-Feed Two-Pipe System with Automatic Return Trap' Proper pipini connections are essential with special appliances for pressure equaliaine and air elimination. tions at Bottom op DownFeed Steam Drop Automatic Return Trap 488 CHAPTER 21 1954 Guide; Each heating unit in a vapor system, as in all two-pipe systems, is pro vided with a graduated or modulating valve which permits the control of heat in the radiator by varying the opening of the valve. Two-Pipe Vacuum Systems Vacuum systems operate under conditions of both low pressure and vacuum, but employ the use of a vacuum pump to insure maintenance of sub-atmospheric pressures in the return piping for all operating conditions. The system may operate transiently with sub-atmospheric 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 up-feed vacuum system is illustrated in Fig. 14, and a down-feed arrangement in Fig. 15. The return risers are connected in the basement into a common return main which slopes downward toward the vacuum pump. The vacuum Steam* Heating Systems 489 float control for the pump at the low point of the return main; located adjacent to the vacuum pump. When the vertical lift is considerable, several lift fittings should be used in steps as shown in Fig.-16. This permits a given lift to be secured with a somewhat lower vacuum than where the vertical distance is served by a single lift. Where several lifts are present in a given system at different locations, the lifting cannot occur until the entire system is filled with steam. A lift connection for location close to the pump, where the size may be above the commercial stock sizes, is shown in Fig. 17. It is desirable that means be provided for manually draining the low point of the lift fittings to eliminate danger of freezing. TWO-PIPE SUB-ATMOSPHERIC SYSTEMS Sub-atmospheric systems are similar to vacuum systems but, in con trast, provide control of building temperature by variation of the heat 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 desirable practice demands a return flowing to the vacuum pump by an uninterrupted downward slope. In some instances local conditions make it necessary to drop the return below the level of the vacuum pump inlet before the pump can be reached. In such an event one of the advantages of the vacuum sys tem is the ability to raise the condensate to a considerable height, by the suction of the vacuum pump, by means of a lift connection or fitting in serted in the return. The height the condensate can be raised depends on the amount of vacuum maintained. It is preferable to limit lift con nections to a single lift at the vacuum pump. A still more preferable arrangement is the use of an accumulator tank, or receiver tank, with a output from the radiators. The radiator heat emission is controlled by varying the pressure, temperature and specific volume of steam in circu lation. 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 side. In the vacuum system, steam pressure above that of the atmosphere exists in the supply mains and radiators practically at all times. In the sub-atmos pheric 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 vacuum which in mild weather "my 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. 490 CHAPTER 21 1954 Guide The control valve may be of the automatic modulating or floating type governed thermostatically from selected control points in the building, or it may be a special pressure reducing valve which will maintain the desired sub-atmospheric pressures by continuous flow into the heating main. In some systems radiator supply valves include adjustable orifices, or are', equipped with regulating 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. A vacuum pump capable of operating at high vacuum is pref-, erable to promote accuracy in the, distribution of steam throughout. the, system, particularly in mild weather. This vacuum is partially selfinduced by the condensation of the steam in the system under conditions of restricted supply used for reduction of the radiator heat emission. The returns must grade downward constantly and uninterruptedly from the radiator return outlets to the inlet of the receiver of the vacuum pump. Fia. 16. Method of Making Lifts on Vacuum Systems when Distance is Over 5 ft Fig. 17. Detail of Main Retubn Lift at Vacuum Pump One radical difference between this and the ordinary vacuum system is that no lifts should be made in the return line, except at the vacuum pump. The receivers are placed at a lower level than the pump, and equipped with float control so that the pump may operate as a return pump under night conditions. The system may be operated in the same manner asthe ordinary vacuum system when desired. 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 sub-atmos pheric method of 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 by-pass around the heaters. Some applications of sub-atmospheric systems are proprietary. TWO-PIPE ORIFICE SYSTEMS Orifice steam heating systems may have piping arrangements identical with vacuum systems. Some of these omit the radiator thermostatic traps, but use thermostatic or combination float and thermostatic traps on all drip points. A return condensate pump with receiver vented to Steam Heating Systems 491 atmosphere,, a return line 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 based on the fact 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 on one side and $ psig on the other, the absolute pressure relation is 14.7 + 0.25 ......................... --? 20 = 0.90 or 90 percent. ................. Should the steam pressure be dropped to psig on the supply 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 vvith steam when there is a given pressure on the_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 pressure in the radiator, provided the supply pipe pressures may be controlled sufficiently close. If orifices are designed on a similar basis for a given system and proportioned to the heating capacity of the radiators they serve, all radiators will heat proportionately to the steam pressure. The range of pressure variation is limited by the per missible noise level of the steam flowing under the pressure difference required for maximum heat output. The control of the steam supply is obtained by a valve placed in the steam main, which maintains a deter mined pressure, and by varying the vacuum in the return; lines. The valves are frequently set manually from a remote location, guided by tem perature indicating stations in the building; or thermostatically controlled from a thermostat on the roof, which automatically measures the dif ferential of outside and inside 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 to maintain the. desired space temperatures, particularly 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 balancing 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- 1954 Guide CHAPTER 21 492 tated as much, as possible, as an air bound system will not heat readily nor properly. In designing the piping arrangement, it is desirable to maintain equivalent resistances in; the supply and return piping to and from a radiator; Arranging the piping so 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 Tabus 1. Obificb Capacities fob Low Pressure Steam Systems This table a based on data from actual tests* Orifice Diameter 64thsof an Inch 6 IN. Hg Differential 5 in. Hg Differential 4 in. Hg. Differential 2 in. Hg Differential .1 in. Hg . Differential Capacity Expressed In Square Feet E P R -- ----------_ 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 18-23 23-29 29-36 36-44 44-52 52-62 62-72 72-83 83-94 94-106 106-119 119-133 133-148 148-163 163-179 16-21 21-27 27-33 33-40 40-48 48-57 57-66 66-76 76-86 86-97 97-109 109-122 122-135 135-149 149-164 15-19 19-25 25-30 30-37 37-44 44-51 51-59 59-67 67-76 76-86 86-97 97-108 108-120 120-133 133-145 10-13 13-17 17-21 21-26 26-31 31-37 37-43 43-49 49-56 56-64 64-72 72-80 80-88 88-98 98-107 8-11 11-14 14-17 17-20 20-24 24-28 28-32 32-37 37-42 42-47 47-52 52-58 58-64 64-71 Capacity Expressed in Pounds per Hour No111111t171121892e102345678910.--TheJra!d_i11a1221223435479t13503869o37..0....553.0...r....00.50855803o-8---------5917--r--11-2122i2433.f..1435i88030369c0374.....e.0...0.5.085.583j808plateis r11e1212124335683c0241649703..o7..,._3.0.08...3.m...03_.5053358---3--_m-6----5-8-1--11-_12122333..e4.2_40386194370n731_...0...d.0.3.._505.33538e0._d__in__th_1_i111212323s40739_12461974.03._..t..58a3.5.0.3..._...8880503b30---_---4-76---l-9--_1-1e1112223.3.._3.12843659134a07_36....r.._0..8..88e.053003_3m__a_d_e_o_111211232452_6f790248_60.2b.4.....53_33.r8.5....3..a803000_0--5----s-34_----6-59--71s-112_1122..2....03s3_243560388246t_...a....8.3.0_000058m__p_in_g_s_,1112231415_60789013_....46..0...50.830_.0..002.3.580--5_-0--3--4-2-3-56_---79-8i1111n_1...1.....853001034_60.730._...t.:5805h08_i_ck cup-*s-bFalopwedoftoStbeeaminsTehrrtoeudgihn OraridfiicaetosrinvtaolvReaudniaiotonrss., by S. S. Sanford and C. B. Sprenger (A.S.H.V.E. Trans accotinodnse, nVsoaL t3e7, 1w93h1,icp.h371o).ccurs in steam piping as well as in radiators must be drained to prevent impeding the ready flow of the steam arid air. The effect of back pressure in the returns and excessive re-vaporization, such as occurs where condensate is released from pressures considerably higher than the vacuum or pressure in the Teturn, 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 outside Steam Heating Systems 493 temperature. Moreover, in rapidly warming up a system even in moder ate 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 system 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 actual operation. The piping design of a heating system is greatly influenced by its operat ing characteristics. Heating systems do not operate under constant condi tions, as 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 appreciable periods at other locations, although at equilibrium conditions the pressures are approximately the same. In designing piping it is of especial 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 intervals than those which are sluggish. Results are given in Fig. 18 from investigations1 to deter mine the rate of condensate and air return from a two-pipe gravity heating system. 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 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 elimination does not coincide with the higher condensing rate. Steam Flow The rate of flow of dry steam or steam with a small amount of water flowing in the same direction, is in accordance with the general laws of gas flow, and is a function of the length and diameter of the pipe, the density f the.steam, and the pressure drop through the pipe. This relationship 494 CHAPTER 21 Table 2. Flow of Steam in Pipes 1954 Guide P = loss in pressure in pounds per square inch. D = inside diameter of pipe in inches. L = length of pipe in feet. & = weight of 1 cu ft of steam. W <= pounds of steam per hour. W = 5220 I (316+\-jWj-*JI* -JqT PdD Lobs Ounces Col 1 1 Pipe Sis* 5220^|-^JNojmnal Actual Internal Diameter - Col 2 Col 3 Avq _ Area or Pipe Sq Inches <1 Steam , *- Press. P6IG V' Col \ Lbngts . ' IB Feet ' 0 0.25 0.50 1.00 2 3 4 5 6 7 8 10 12 14 16 20 24 28 32 40 48 80 160 320 480 65.28 1 1 1.049 0.864 0.536 -1.0a 0.187 20 2.240 92.28 IH 1.380 1.496 1.178 --0.5a 0.190 40 130.5 184.6 1H 1.610 2 2.067 2.036 3.356 1.828 3.710 0.0 0.193 0.3 0.195 60 80 226.0 261.0 291.8 2H 2.469 3 3.068 3H 3.548 4.788 7.393 9.887 6.109 11.183 16.705 1.3 0.201 100 2.3 0.207| , 120 5.3 0.2231 140 319.7 4 4.026 12.730 23.631 10.3 0.248 160 345.3 369.1 4'A 4.506 5 5.047 15.947 20.006 32.134 15.3 0.270 43.719 20.3 0.290 180 200 412.7 6 6.065 28.886 71.762 30.3 0.326 250 452.0 7 7.023 38.743 106.278 40.3 0.358 300 488.3 J 8 7-981 50.027 149.382 50.3 0.388 350 522.0 | 9 8.941 62.786 201.833 60.3 0.415 400 583.6 10 10.020 78.854 272.592 75.3 0.452 450 639.3 12 12.000 113.098 437.503 100.3 0.507 j 500 690.5 14 13.250 137.880 566.693 125.3 0.557J 600 738.2 16 15.250 182.655 816.872 150.3 0.603 700 825.4 1 Column 1X2X3X4- lb of steam 175.3 0.645 904.1 I pipe r>our ratghiavet nwcilol nfdloitwionth. rough a straight 200.3 0.685 800 900 1.580 1.290 1.120 1.000 0.912 0.841 0.793 0.741 1 0.710 0.632 0,578 0.538 0.500 0.477 0.447 0.407 0.578 0.354 0.533 1167 2 1 - 1.3 lb press. - 100 ft equivalent length: "I 130 5 X 3.710 X 0.201 X 1 - 7-2 lb per hour. 1650.7 1 o? o y 4b <a 3SS.8 sq ft equivalent radiation. 2334.5 2859.1 smteeTarama:a>. ljecpo2inpddeoeeansssanfotoiuotnnadlilnoinwcpofrvoaercrteeicdnetr.paiipneedanwdatreoruginhnloesws-pirnescsoumr 1000 1200 1500 0.316 0.289 0.258 zow I u < >'"> <*--" hour- Steam Heating Systems 495 has been established by Babcock in the formula given at the top of Table 2. In Columns 1, 2, 3, and 4 of this table, the numerical values of the factors for different pressure losses, pipe diameters, steam densities and lengths of pipe have been worked out in convenient form so that the steam flowing in any pipe may be calculated by multiplying together the proper factors in each column, as shown in the example at the bottom of the table. Pipe Sizes The determination of pipe sizes for a given load in steam heating depends on the following principal factors: . I. The initial pressure and the total pressure drop which may be allowed between the source of supply and at the end of the return system. . ' 2. The maximum velocity of steam 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 steam supply to the farthest heating unit. 4. The direction of flow of the condensate, whether against or with the steam. Initial Pressure and Pressure Drop 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 impor tant that: (1) the total pressure drop does not exceed the initial .gage pressure of the system, and in actual practice it should never exceed onehalf 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 sub-atmospheric, which normally operate under controlled partial vacua and orifice and vapor systems, which at times operate under such partial vacua as may be obtained due to the condition of the fire; and (4) the rise in water due to pressure drop does not exceed the difference in level, for gravity return systems, between the lowest point on the steam main, the heating units, or the dry-return, and the boiler water line. The present tendency in steam heating unmistakably points toward a . constant lowering of initial pressures, even to those below atmospheric, and to the use of reasonably small pressure drops because a system de signed in this manner will operate under higher pressures without dif ficulty. When a system designed for a relatively high initial pressure and a relatively high pressure drop is operated at a lower pressure, it is likely to be noisy and have poor circulation. 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 velocity permissible without interfering with the condensate flow. A.S.H.V.E. Research Laboratory experiments limit this to the capacities given in Table 3 for horizontal pipes at varying grades. Maximum Velocity The capacity of a steam pipe in any part of a steam system depends upon the quantity of condensate present, the direction in which the con densate is flowing, and the pressure drop in the pipe. Where the quantity f condensate is limited and is flowing in the same direction as the steam, only, the pressure drop need be considered. When the condensate must flow against the steam, even in limited quantity, the velocity of the steam fflust not exceed limits above which the disturbance between the steam and 496 CHAPTER 21 1954 Guide the counter-flowing water may produce objectionable sounds, such as water hammer,, or may result in the retention of water in 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 pipe 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 certain conditions act as a restriction in pipe size. Reaming Important . Three factors of uncertainty always exist in determining the capacity of any steam pipe. The first is variation in manufacture, which appar ently cannot be avoided. The second is the care used in reaming the ends of the pipe after cutting. The effect of both of these factors increases as the Table 3. . .. Comparative Capacity of Steam Lines at Various Pitches fob Steam and Condensate Flowing in Opposite Directions* Pitch of Pipe in Inches per 10 Ft. Velocity in Ft per Sec Pitch or Pipe H IN. H in. 1 IN. 1H in. 2 IN. 3 IN. 4 IN. 5 IN. Pipe Size Inches >, '3 ad o >V a >> *aa3 ' *> i 6s >> `3 a3 9 > i `3dad > 3 U >> '3dad U *3 > 3 '3 & 6 > 3 >. " >> dQd. o >. 3 .'3da <3 > i - Capacity Expressed in Square Feet EDR H' 1 mm 2 25.0 12 30.3 . 45.8 12 52.6 104.9 18 in;2 142.6 18 159.0 236.0 19 263.5 14 37.3 15 63.0 20 133.0 21 181.0 20 299.5 18 40.4 17 70.0 23 144.5 23 196.5 23 325.5 l 19 42.5 20 75.2 25 154.0 25 209.3 25 346.5 20 46.1 22 83.0 27 165.0 27 224.0 27' 371.5 21 47.5 23 87.9 28 172.6 28: 234.8 28 388.4 22 49.3 25 90.2 29 178.2 30 242.6 29 401.1 23 26 31 31 30 Capacity Expressed in Pounds per Hour H 1 w 2 6.3 11.5 26.2 35.7 59.0 12 12 18 18 19 7.6 13.2 29.3 39.8 65.9 14 15 20 21 20 9.3 15.8 33.3 45.3 74.9 18 17 23 23 23 10.1 17.5 36.1 49.1 81.4 19 20 25 25 25 10.6 18.8 38.5 52.3 86.6 20 22 27 27 27 11.5 20.8 41.3 56.0 92.4 21 23 28 28 28 11.9 22.0 43.2 58.7 97.1 22 12.3 25 22.6 29 44.6 30 60.7 29 100.3 23 26 31 31 30 * Data from The American Society of Heating and Ventilating Engineebs Research Laboratory. pipe size decreases. According to A.S.H.V.E. Research Laboratory tests, either of these factors may affect the capacity of a 1-in. pipe as much as 20 percent. The third factor is the uniformity in grading the pipe line. All of the capacity tables given in this chapter include a factor of safety. However, the factor of safety referred to does not cover abnormal defects or constrictions, nor does it cover -pipe not properly reamed. Equivalent Length of Run All tables for the flow of steam in pipes, based on pressure 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 so many feet of straight run of the same size of pipe. Table 4 gives the number 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 Steam Heating Systems 493 length of run as distinguished from the actual length of pipe in feet. The length of run is not usually known at the outset; 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 usually is taken as double the actual length of pipe. TABLES FOR PIPE SIZING FOR LOW PRESSURE SYSTEMS* (Tables 5, 6, and 7 are based on the actual inside diameters of the pipe and the condensation of i lb (4 oz) of steam per square foot of equivalent direct radiation .(abbreviated EDR) per hour. The drops indicated are Table 4. Length in Feet of Pipe to be Added to Actual Length of Run-- .. Owing to Fittings--to Obtain Equivalent Length Size or Pips Inches. Length,in Feet to be Addbdto Run Standard Elbow Side Outlet Tee' Gate Valve* Globe Valve* : Angle Valve* 13 1.8 2.2 iy* 3.0 2H 2% 3.5 . 4.3 5.0 6.5 4 8 9 6 180 12 14 11 13 17 : 2i dSV 30 `Valve la full open position* 3 4 5 6 7 8 11 . 13 15 18 22 27 35 45 53 63 0.3 0.4 0.5 0.6 0.8 1.0 1.1 1.4 1.6 21..29 2.8 3.7 4.6 65..45 14 2138 3249 46 54 689260 112 136 180 223700 310 7 10 12 15 2128 27 .34 40 45 56 67 112 r 132 ! 152 Example of length in feet ofpipeto be added to actual length of run. m. UDOW8 )Equivalent Length 169.9 ft .................. .... H drops in pressure per 100 ft of equivalent length of run. The pipe is assumed to be well reamed and without unusual or noticeable defects. Table 5 may be used for sizing piping for steam heating systems by pre-determining the allowable or desired pressure drop per 100 equivalent feet of run, and reading from the column for that particular pressure drop. This applies to all steam mains on both one-pipe and two-pipe systems, vapor systems; and vacuum systems. Columns !? to G, inclusive, are used where the steam find condensate flow in the same direction, while Columns -a and I are for cases where the 6team and condensate flow in opposite directions, as in risers and runouts that are not dripped. Columns J, K, and L are for one-pipe systems and cover riser, radiator valve and vertical connection sizes, and radiator and runout sizes, all of which are based on the 498 CHAPTER 21 1954 Guide Table 5, Steam Pipe Capacities for Low Pressure Systems (Reference to this table will be by column letter A through L) ' This table is based on pipe size data.developed through the research investigations of The American Society of Heating and Ventilating Engineers. CAPACITIES OF STEAM MAINS AND RISERS . Special Capacities fob (Onbs-Pipb Stbtkmb Only Pipe SIunb. Dibbcyioiy of Condexbats Flow w Pipb Lise With the Steam in One-Pipe and Two-Pipe Syatema A psi or 1 o Drop Aopr a i Os Drop * P Or 1 Os Drop 1 pel or 2 Oi Drop 40e Drop ipei 8 0s Drop Against the Steam Two-Pipe Only ' Supply Risers Up- Feed Vertical Hori zontal Radiator Valves and Vertical Conneeticmz Radiator and Riser Runouts B CD H* / /b K Capacity Expressed in Square Peel E D R 1 n H 2 21 3 31 4 5 6 8 10 12 16 30 ._ 30 __ 25 39 46 56 87 . 100 122 134 155 190 273 315 386 449 518 635 822 948 1,160 79 173 269 546 898 1,650 111 245 380 771 1,270 2,330 157 56 346 122 538 190 1,091 386 1,800 635 3,290 1,130 34 75 108 195 395 700 1,230 1'740 3^210 5,280 11)000 20,000 32*000 61', 000 1,420 2,010 3',710 6,100 12,700 23,100 37,100 69)700 1,740 2,460 4,550 7,460 15,500 28,300 45,500 84,800 2,460 3,480 6,430 10,550 21,970 40,100 64,300 121,000 3,470 4,910 9,090 14,900 31,070 56,700 91,000 170,000 4,910 6,950 12,900 21,100 43,900 80,200 129,000 242,000 1,550 2,040 4,200 7,200 15,000 28,000 46,000 88,000 1,150 1,700 3,150 5,600 12,000 23,000 38,000 76,000 45 98 152 288 464 800 1,140 1,520 -- -- -- --- __ 28 62 93 169 -- -- --- . -- --- . -- -- -- -- -- 28 62 93 169 260 475 755 1,110 2,180 -- -- Capacity Expressed in Pounds per Hour 1 1 11 H 2 21 3 31 4 5 6 8 10 12 16 _I 8 - | _- 12 14 20 28 25 31 43 61 39 48 67 95 79 97 137 193 130 159 225 318 237 291 411 581 355 434 614 869 503 614 869 1,230 928 1,140 1,610 2,270 1,520 1,870 2.640 3,730 3,170 3,880 5,490 7,770 5)790 7,09C 10,000 14,200 9,290 11,400 16,100 22,700 117,400 21,200 30,300 42,400 8_ 14 9 31 19 48 27 97 49 159 99 282 175 387 288 511 425 1,050 788 1,800 1,400 3,750 3,000 7,000 5,700 11,500 9,500 122,000 19,000 6 __ 11 7 20 16 38 72 116 200 286 380 ---' ' -- 23 42 -- -- -- -- -- -- -- - --- ---- ---- ---- 7 7 16 23 42 65 119 186 278 545 All Horizontal Meins and Down-Feed Ruen UpFeed Risen and Un dripped Run- UpFeed Risen outa ator Con nec tions Run* outs Not Dripped Note.--Steam at an average pressure of 1 peig is used as a basis for calculating capacities. All drops shown are in psi per 100 ft of equivalent run--based on pipe properly reamed. Do not use Column H for drops of 1/24 or 1/32 pei; substitute Column C or Column B as required. b Do not use Column / for drop 1/32 psi except on sizes 3 in. and over; below 3 in. substitute Column B.~ c Pitch of horizontal runouts to risers and radiatorsshould be not Jess than 1/2 in. per ft. Where this pitch cannot be obtained, runouts over 8 ft in length should be one pipe size larger than called for in Table 5. Steam Heating Systems 499 critical velocities of the steam to permit the counter flow of condensate without noise. ' Return piping may be sized with the aid of Tables 6 and 7 where pipe capacities for wet, dry, and vacuum return lines are shown for the pres sure drops per 100 ft corresponding to the drops in Table 5. It is cus tomary to use the same pressure drop on both the steam and return sides oj a system. . Example l: 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 over2-psig? Solution: It will be assumed, 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 1,000 ft. Then, with the pressure drop not over one-half of the initial pressure, the drop could be 1 psi or less- With a pressure drop of 1 psi and a length of run of 1,000 ft, the drop per 100 ft would be is psi, while if the total drop were 1 psi, the drop per 100 ft would be psi. In the first instance the pipe could be sized according to Column D for fy psi per 100 ft, and in the second case, the pipe could be sized accord ing to Column C for & psi. 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 determined. 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.tbe lines resized. Ordinarily, resizing will be unnecessary. TABLES FOR PIPE SIZING FOR HIGH PRESSURE SYSTEMS Many of the recent installations of heating systems for large industrial type buildings have been designed for the use of high pressure 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 con trolled by the air temperature in the room, fan inlet or outlet. Tables 8 to 11 may be used for the sizing of steam and return piping for systems of 30 and 150 psi pressure at various pressure drops. These tables are based on Babcock's formula, and have been used as the basis of design for a number of years. 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 as follows; 1 .For the steam, main and dripped runouts to risers where the steam and condensa?*flow in the same direction, use iV-psi drop (Column D). 2. Where the riser runouts are not Gripped and the steam and condensate flow b opposite directions, and also in the radiator runouts where the same condition occuir use Column L. 3. For up-feed steam risers carrying condensate back from the radiators, use Column J. 4. For down-feed systems, the mam risers of which do not carry any radiator con densate, use Column H. 5- For the radiator valve size and the stub connection, use Column K. & For the dry-return main, use Column V. 7. For the wet-return main, use Column T. On systems exceeding an equivalent length of 200 ft, it is suggested that the total drop be not over 1 psi. The return piping sizes should corre spond with the drop used on the steam side of the system. Thus, where A-psi drop is being used, the steam main and dripped runouts would be Steam Heating Systems 501 502 CHAPTER 21 1954 Guide Table 8. Steam Pipe Capacities for 30 Psig Steam Systems* Capacity Expressed, in Pounds per Hour ` - (Steam and Condensate Flowing in Same Direction) Pipe Size Inches DDrroopp iinn PPrreessure--Pounds per 100 Ft in Length * *4 1H 1*4 21*4 2*4 3 3*4 456 ,11280 15 31 69 107 217 358 651 979 1,390 2,560 4,210 8,750 16,300 25^600 22 46 100 154 313 516 . 940 1,410 2,000 3,640 6,030 12,600 23,500 36,900 31 63 141 219 444 730 1,330 2,000 2,830 5,230 8,590 17,900 33,200 52,300 77 172 267 543 924 1,630 2,450 3,460 6,400 10,400 21,900 40,600 64,000 199 309 ' 627 1,030 1,880 - 2,830 4.000 7,390 12,100 25,300 46,900 74.000 63 125 281 437 886 1,460 2,660 4,000 5,660 10,500 17,200 35,100 66,400 104,500 , Note: Steam atT^S^e pressure of 30 psig is used as the basis for calculating the above table. sized from Column C; radiator runouts and undripped riser runouts from Column L; up-feed risers from Column J; the main riser on a down-feed system from Column C (it will be noted that if Column H is used the drop would exceed the limit of psi); the dry return from Column R; and the wet-return from Column Q. ' With a sVpsi drop the sizing would be the same as for -5^ psi, except that the steam main and dripped runouts would be sized from Column B, the main riser on a down-feed system from Column B, the dry-return from Column O, and the wet-return from Column N. Notes on Gravity One-Pipe Air-Vent Systems 1. Pitch of mains should not be less than $ in. in 10 ft. 2. Pitch of horizontal runouts to risers and radiators should not be less than \ in. per foot. Where this pitch cannot be obtained, runouts over 8 ft in length should be one size larger than called for in the table. . 3. In genera), it is not desirable to have amain less than 2in. The diameter of the far end of the supply main should not be less than half its diameter at its largest part. Table 9. Steam Pipe Capacities for 150 Psig Steam Systems* Capacity Expressed in Pounds per Hour (Steam and Condensate Flowing in Same Direction) Drop in Pressure--Psi per 100 Ft in Length Pipe Size . Inches H *4 H 44 1 2 5 H 1 1*4 m 2 2** 3 3*4 4 5 6 8 10 12 29 58 130 203 412 683 1,240 1,860 2,630 4,860 7,960 16,600 30,800 48,600 41 82 185 287 563 959 1,750 2,630 3,720 6,880 11,300 23,500 43,400 68,800 58 117 262 407 825 1,360 2,480 3,720 5,260 9,730 16,000 33,200 61,700 97,300 71 143 320 497 1,010 1,650 3,020 4,550 6,430 11,900 19,500 40.600 75.600 no.000 82 165 370 575 1,170 1,920 3,500 5,250 7,430 13,800 22,600 47,000 87,300 138,000 116 233 523 813 1,650 2,710 4,940 7;420 10.500 19.500 31,900 66,400 123.000 194.000 184 369 827 1.290 2,600 4.290 7,820 11,700 16,600 30,800 50,400 105.000 195.000 307,500 * Note: Steam at an average pressure of 150 psig is used as the basis for calculating the above table. Steam Heating Systems Table 10. Return Pipe Capacities for 30 psig Steam Systems* Capacity Expressed in Pounds per Hour . 503 Pipb Size X i m m .2 m 3 3X 4 5 6 Deop in Pressure--Pounds per 100 Ft in Length X 115 230 485 790 1,580 2,650 4,850 7,200 10,200 19.000 31.000 . X 170 340 710 1,160 2.360 3,900 7,100 10,600 15,000 27,800 45,500 M 245 4) 1,025 1,670 3,400 5,600 10.300 15.300 21,600 40.300 65,500 X 308 615 1,290 2,100 4,300 7,100 12,900 19,200 27.000 55,500 83.000 Note: The above table is based on steam at pressures of 0 to 4 psig. I 365 730 1,530 2,500 5,050 8,400 15.300 22,800 32.300 60,000 98,000 : . ... _______ouuuiu uc urippea wnere necessary. 5. Where supply mains are decreased in size they should be dripped, or be provided with eccentric-couplings, flush'on bottom. Example S: Size the one-pipe gravity steam system shown in Fig. 19 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 215 ft. If the equivalent length of run is taken at double this, it will amount to 430 ft, and with a total drop of i psi the drop per 100 ft will be slightly lessthan ^ psi. It would be well in this case to use jV psi, and this would result in the theoretical sizes indicated in Table 12. These theoretical sizes, however, should be modified by not using a wet-return less than 2 in., while the main supply, 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 the wet-return is made 2 in. ____ __ _ u u v \yi\ GlOl O 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. Table 11. Return Pipe Capacities for 150 psig Steam Systems* Capacity Expressed in Pounds per Hour Pipe Size Inches 1 y* ix 2 2M 3 3X 4 5 6 H 156 313 650 1,070 2,160 3.600 6,500 9.600 13,700 25,600 42,000 Drop in Pressure--Psi pee 100 Ft in Length H 232 462 960 1,580 3,300 5.350 9,600 14,400 20.500 38,100 62.500 H 360 690 1,500 2,460 4,950 8,200 15.000 22,300 31;600 58,500 96.000 X 465 910 1,950 3,160 6,400 10.700 19.500 28.700 40.500 . 76,000 125,000 560 1,120 2,330 3,800 7,700 12,800 23,300 34.500 49,200 91.500 150,000 note: 1 he above table is baaed on steam at pressures of 1 to 20 psig 2 890 1,780 3,700 6,100 12,300 20,400 37,200 55,000 78,500 146.000 238.000 504 CHAPTER 21 Table 12. Pipe Sizes pob One-Pipe Up-Feed System Shown in Fig. 19 PAAT O, S..TEJI Section or Vipe Radiation TTPPT-T OP EDR Sq Ft Theoretical Pipe sise (Inches) Branches to radiators......... Branches to radiators......... Riser-----`............................... Riser.................................... Riser.................. 1................... Runout to riser................... Supply main........................ Branch to supply main. ... Dry return main........... Wet return main............ Wet return main................. Wet return- main................. a to & b to c c to d d to e eix>f f tot 0 to h k to } ./ to k fc to m m to n n to p 100 50 200 300 400 500 600 600 600 600 600 600 600 600 2 m 2 2M m 3 3 3H 3 2H 1H 1 1954 Guide I M I I 50 Lula (ZL'iJ3 2nd a Fig. 19. Riser, Supply Main and Return Main op One-Pipe System 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 psig, 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, of course, caused by the dis charge of traps and flashing of condensate into steam because the return line pressure is below that corresponding to the saturation temperature of the condensate. The usual practice in the sizing of high pressure returns has been to size on the basis of psi per 100 ft of pipe for 30-psig sys tems, and 1 psi per 100 ft for 150-psig systems. This is an average figure which corresponds generally to several of the previously published tables for the design of high pressure return piping. Notes on Two-Pipe High Pressure Systems Pitch of mains should not be less than 1 in. in 10 ft. Pitch of horizontal runouts to risers and heating units should not be less than i in. per ft. SIZING PIPING FOR TWO-PIPE LOW PRESSURE SYSTEMS Piping for two-pipe low pressure systems is sized in the same manner as for two-pipe vapor systems, except that the pressure drop throughout the system can be based on \ psi to 1 psi drop. . SIZING PIPING FOR TWO-PIPE VAPOR SYSTEMS While many manufacturers of patented vapor heating accessories have their own schedules for pipe sizing, an inspection of these sizing 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 i:" Steam Heating Systems 505 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 radiators. : For small vapor systems where 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 from Column D, Table 5, while riser runouts not dripped and radiator runouts should employ Column /. The up-feed steam risers should be taken from Column H. On the returns, the risers should be sized from Tables 6 and 7, Column U (lower portion), and the mains from Column U (upper portion). It should again be noted that the pressure drop in the steam side of the system is kept the same as on the return side, except where the flow in the riser is concerned. On a down-feed system, the main vertical riser should.be sized from Column H, but the down-feed risers can be taken from Column D, al though it so happens that the values in Columns D and H for small systems correspond. This will not hold true in larger systems. For vapor systems over 200 ft of equivalent length, the drop should not exceed | psi to | psi, if possible. Thus, for a 400 ft equivalent run the drop per 100 ft should- be not over psi divided by 4, or -/j psi. In this case the steam mains would be. sized from Column B, the radiator and undripped riser runouts from Column 1; the risers from Column B, because Column H gives a drop in excess of jV psi- On a down-feed system, Column B Would have to be used for both the main riser and the smaller risers feeding the radiators in order not to increase the drop over aV psi. The return risers would be sized from the lower portion of Column 0 and the dry return main from the upper portion of the same column, while any wet returns would be sized from Column N. The same pressure drop is applied on both the steam and the return sides of the system. ' Notes on Vapor Systems. 1. Pitch of mains should not be less than i in. in 10 ft. 2. Pitch of horizontal runouts to risers and radiators should not be less than J in. per ft. Where this pitch cannot be obtained, 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 supply main smaller than 2 in. 4. When necessary, supply main, supply risers, or runouts to supply risers should he 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, sub-atmospheric and orifice systems are usually employed in large installations and have total drops varying from 1 to Psi- Systems in which the maximum equivalent length does not exceed ft preferably employ the smaller pressure drop, while systems over ft equivalent length of run, more frequently are designed for the higher Ir P> owing to the relatively greater saving in pipe sizes. For example, a "ystem with 1200 ft longest equivalent length of run would employ a drop. ^ ' Ps' divided by 12, or V* psi. In this case, the steam main uld be sized from Column C, Table 5, and the risers also from Column (Column H could be used as far as critical velocity is concerned, but the /op would exceed the limit of psi). Riser runouts, if dripped, would C?: Column C but, if undripped, would use Column I; radiator runouts, oiumn I; return risers, lower part of Column S, Tables 6 and 7; return Qouts to radiators, one pipe size larger than the radiator trap connections. 506 CHAPTER 21 1954 Guide Notes on Vacuum Systems. 1. It is not generally considered good practice to exceed J psi drop per 100 ft of equivalent run, nor to exceed 1 psi total pressure drop in any system. 2. Pitch of mains should not be less than } in. in 10 ft. 3. Pitch of horizontal runouts to risers and radiatorB should not be less than 1 in. per ft. Where this pitch cannot be obtained, runouts oyer 8 ft in length should be one size larger than called for in the table. ' 4. In general, it is not considered desirable to have a supply main smaller than 2 in. 5. When necessary, the supply main, supply riser, or runout to a supply riser should be dripped separately through a trap into the vacuum return. A connection should not be made between the steam and return sides of a vacuum system without . interposing a trap to prevent the steam from entering the return line. 6. Lifts should be avoided if possible, but when they cannot be eliminated they should be made in the manner described in this chapter. 7. No lifts can be used in orifice and atmospheric systems. In sub-atmospheric systems the lift must be at the vacuum pump. SIZING PIPING FOR INDIRECT HEATING UNITS Pipe connections and mains for indirect heating units are sized according to the quantity of steam condensed by each unit. The condensation 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 condensation has been obtained for each unit, the pipe sizes should be based on the length of run and the pressure drop de sired, 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 given in Figs. 2 to 17 inclusive, indicate the various systems to be supplied by separate boiler plants, it is also possible to have steam supplied at high pressure by a boiler plant remotely located. In this case steam is supplied directly to the system or through a pressure reducing valve. Condensate can either be returned to the boiler plant or wasted to the sewer. The general arrangement of the systems fed through a pressure reducing valve will not vaiy from those illustrated with a boiler supply. When high pressure steam is being supplied and lower steam pressures are required for heating, for domestic hot water, for utility services, etc., one or more pressure reducing valves (pressure regulators) are required. These are used in two classes of service, one where the steam must be shut off tight to prevent the low pressure building up at time of no load, and the other where the low pressure lines will condense enough steam to offset normal leakage through the valve. In the latter case, double seated valves may be used in a manner that reduces the work required of the diaphragm in closing the valve and consequently, the size of the diaphragmThese valves also control the low pressures more closely under conditions of Vvaalrvyeinsgthhaigthshpuretsosuffreasll. steam are called dead end type. They are single seated, and some of them have pilot operation that provides close eontmi of the reduced pressure. If a thermostatically controlled valve is installed Steam Heating Systems 507 after, and near, a reducing valve in such a manner as to cut off the passage of steam, the dead end type should be used. It is common practice, when the initial steam pressure is 100 psig or higher, to install two-stage reduction. If the radiation served is cast-iron, the ASME code requires two reducing valves when the inlet pressure exceeds 50 psig. This makes a quieter condition of steam flow, as it is apparent that with one reduction, as for example from 150 to 2 psig, there is a smaller opening with greater velocity across the reducing valve and,, consequently, more noise. A two-stage reduction also introduces a source of safety, since if one reducing valve were to build up its discharge pressure, this excess pressure would not be so great as the case might be in a one-stage reduction. If an installation requires single seated valves and the pilot type cannot be used, it is necessary to use two-stage reduction, as single seated valves require sufficient diaphragm area to overcome the unbalanced pressure; underneath the single valve. In many cases the large diameter of dia phragm required would make it impractical in construction. With a two- stage reduction, the diaphragm diameter required would be reduced. If a one-stage reduction is desired, it is necessary to use a pilot controlled pressure reducing valve, where low pressures are to be maintained closely. In making a two-stage reduction, allowance for expansion of steam on the low-pressure side of the valve should be made by increasing the pipe size. This also allows steam flow to be at a more nearly uniform velocity. Separating the valves by a distance up to 20 ft is recommended to reduce excessive hunting action of the first valve. .. When the reduced pressure is approximately 15 psig or lower, the weight and lever diaphragm valve gives the best results with minimum main tenance. Above 15 psig, spring loaded diaphragm valves should be used, because of the extra weights required on weight and lever type. Pressure equalizing lines should not be connected too close to the valve. They should be connected'into the bottom of the reduced pressure steam main, to allow maximum condensate to exist in the equalizing lines, or the connection can be made into the top of the main if a water accumulator is used to reduce the variation of the head of water on the diaphragm. Care should be exercised in selecting the size of a reducing valve. The safest method is to consult the manufacturer. It is essential that sizes pf 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 bring about wire-drawing of valve and seat, due to small lift of the valve seat. On installations where the steam requirements are relatively large and variable in mild weather or reduced demand periods, wire-drawing may occur. 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 50,000 lb of steam per hour are required, the size of one valve is on the basis of 0.7 X 50,000 lb, or 35,000 lb, and `he other on the basis of 0.3 X 50,000 lb, or 15,000 lb. During the mild r reduced demand periods, steam will flow through the smaller valve oly. During the remainder of the season, the larger valve is set to control I wbatever low pressure is desired, and the smaller one at a somewhat 'ver pressure. Thus, when steam flow is not at its maximum, the smaller valve is closed, but it opens automatically when the maximum CHAPTER 21 1954 Guide 508 steam demand occurs, because this maximum demand , creates a slight pressure drop in the service line. ' Theinstallation of reducing valves in pipe lines requires detailed planning. They should be installed to give ease of access for inspection and repair, and wherever possible, with diaphragm downward, except in cases of pilot op' Terhaetered svhaolvuelds. be a by-pass around each reducing va; lve of size equal to one-half the size of reducing valve. The globe valve in by-pass line should be of a good type of construction, and must shut off absolutely tight. A steam pressure gage, graduated up to the initial pressure, should be installed on the low pressure side. Safety valves located on the low: pressure side should be set 5 psi higher than the final pressure, but may be' 10 psi higher than the reduced pressure if this reduced pressure is that of the first stage reduction of a double reduction. Strainers are sometimes installed on the inlet to the reducing valve, but are not required before a Fio. 20. The Hartfobd Retubn Connection second-stage reduction. If a two-stage reduction is made, it is well to, install a pressure gage immediately before the reducing valve of the second-stage reduction also. In sizes 3 in. and above, it is advisable to install a drip trap between the two reducing valves. . BOILER CONNECTIONS SteCaamst-iron, sectional heating boilers usually have several outlets in the top. Two or more outlets should be used whenever possible to reduce the velocity of the steam in the vertical uptakes from the boiler, and thus to prevent carrying of water into the steam main. - ReCtuarsnt-iron boilers are generally provided with return tappings on both sides,: while steel boilers are generally equipped with only one return Steam Heating Systems 509 Upping. Where two tappings are provided, both should be used to effect proper circulation through the boiler. The return connection should include either a Hartford return connection or a check valve to prevent the. accidental loss of boiler .water to the returns, with consequent danger of boiler damage. The Hartford return connection is to be preferred over the check valve, because the latter is apt to stick or not close tightly and, furthermore, because the check valve offers additional resistance to the condensate coming back to the boiler, which in gravity systems would raise the water line in the far end of the wet-return several inches. In order to prevent the boiler from losing its water under any circum stances, the use of the Hartford return connection is recommended. This connection for a one- or two-boiler installation is shown in Fig. 20. The essential features of construction of a Hartford return connection are: (1) a direct connection (made without valves) between the steam side of the boiler and the return side of the boiler, and (2) a close nipple, or preferably an inverted Y-fitting connection about 2 in. below the norma) boiler water line from the return main to the boiler steam and return pressure balance connection. Equalizing pipe connections between the steam and return are given in Fig. 20, based on grate areas, but in no case shall this pipe size be less than the main return piping from the system, Sizing Boiler Connections Little information is available on the sizing of boiler runouts 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 header 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 cal culating 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 horizontal 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 same 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 will 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 nne to each boiler would require only half of the capacity of the entire pstem, or, if the boiler capacity were more than one-half the entire system *oad, the return would be sized on the basis 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. ' Withreturns pumped from a vacuum or receiver return pump, the size 01 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, `he relative boiler loads should be considered, as in the case of gravity 510 CHAPTER 21 1954 Guide return connections. 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 return of the condensate permits the water to pass repeatedly through the cycle of vaporization, with subsequent condensation 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. Serious corrosion is more frequently found in systems in which the con densate is wasted, and fresh make-up water is continually being introduced. A generally accepted condensate pump unit for low pressure 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 condensate returned per minute, and the pump generally has a delivery rate of 3 to 4 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 condensate unit is illustrated in Fig. 9. VACUUM HEATING PUMPS On vacuum systems, where the returns are under a vacuum, and sub: atmospheric systems, where the supply piping, radiation and the returns are under a vacuum, it is necessary to use a vacuum pump to discharge the air and non-condensable gases to atmosphere and to dispose of the con densate. 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 bJso frequently used where steam at suitable pressures is available, the steam being used afterward for building heating. The usual vacuum pufflP unit consists of a compact 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 specialsteaffl turbine 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 condition3 such as installations where it is necessary to return the condensate to a high pressure boiler, auxiliary water pumps may be supplied. In some instances separate air and water pumps may be used. Steam Heating Systems 511 For rating purposes3 vacuum pumps are classified as low vacuum and high vacuum. Low vacuum pumps are those rated for maintaining 5J in. Hg vacuum on the system, and high vacuum pumps are those rated to maintain vacuums above 5 in. Hg. Manufacturers of vacuum pumps specify that the. standard capacity of pumps shall be 0.3 to 0.5 cfm of air removal, and 0.5 gpm of water per 1000 EDR served; This capacity is at 5| in. Hg of vacuum, and with con densate at 160 F. The larger air capacity is for smaller systems, and the smaller capacity for the larger systems. Some manufacturers, however, specify more air capacity than stand ard where higher vacuums are desired and where air leakage is anticipated. The vacuum that can be maintained on a system depends upon the relationship of the air leakage rate into the system to the operating air capacity of the hydraulic evacuator when operating at any given return line temperature. The hotter the returns; the lower will be the possible vacuum for a given air leakage rate into the system. It is particularly essential on high vacuum installations to see that the entire system is tight in order to reduce the amount of inward air leakage and, further more, to see that relatively higher temperature steam is prevented from entering the vacuum return lines through leaky traps, high pressure drips; etc. It is for this reason that the condensate from-equipment using steam at high pressures should not be connected directly to a vacuum, return line, but should drain , to a flash tank or flash 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 controlled 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 condi tions. 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 operation 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 sub-atmospheric systems where orifices are used, the vacuum pump control maintains a pressure difference between the supply and the return piping, which is held within relatively close units. There are other sub-atmospheric systems which utilize special temperature-pressure actuated controls for maintaining the desired condi tions 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 electnc 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. Ihey are usually supplied with an air separating tank, open to atmosphere, P'aced on the discharge side of the pump, and at an elevation sufficiently VALVE ACCESS PLUG Steam Heating Systems THERMOSTATIC DISC ELEMENT^ 513 ! r- i :! 1 }`ii; m\ DRAIN PLUG Fig. 22. Multiport Float Trap 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 boilers, 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 condensate 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 itslatent heat, and to allow condensate and air to pass as soon as it accunm: lates. 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 operating 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) tilting, (9) lifting, and (10) 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 VALVE AND ORIFICE Fig. 25. Typical Float and Thermostatic Trap . BLOW OFF ' Fig. 26. Upright Bucket. Trap chamber, the float rises and gradually opens the valve, and the pressure of the steam pushes the condensate out of the valve. The discharge from a float trap is generally continuous, since the opening 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. Unless 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 j 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 traps should be equipped with a thermostatic air vent (See Float and Thermo static Traps). Figs 21 and 22 illustrate types of float traps which are in use at the present time. . Thermostatic Traps. 'Thermostatic traps function by means of elements which expand and contract under the influence of heat and cold- Early types of thermo static traps employed carbon posts and bi-metallic elements for expansion. In general, the modern 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 in contact with the expansive ele ment. The pressure created in either case expands the element and closes the valve of the trap against the escape of steam. When condensate or air comes in contact with the element, it cools and contracts, opening the valve and allowing them to escape. The discharge from this type of trap is intermittent. Thermostatic traps find their use generally for the draining of condensate from radiators, convectors, 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 sub stance from entering the trap. A cooling leg of a length of pipe should also be proyided ahead of the trap on unit heaters and similar apparatus to cool the condensate m order to help in the trap action. Thermostatic traps are made in sizes from J P .ig 27- Inverted Bucket Trap Fig. 28. Inverted Bucket Trap, with Central Guide 514 CHAPTER 21 1954 Guide to2in.,and for pressures ranging from vacuum conditions to 300 psig. Figs; 23 and 24 illustrate types of thermostatic traps which are available at the present time. Float and Thermostatic Traps. This type of trap is a combination of the float trap and the thermostatic trap, and finds 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 flow of steam around the float valve. Float and thermostatic traps are made in sizes from to 2 in. and usually operate under pressures varying from vacuum conditions to 40 psig, although some are made to operate at a maximum pressure of 200 psig. Fig. 25 illustrates a typical float and thermostatic trap. Upright Bucket Traps. In this type of trap, the condensate enters the trap cham ber and fills 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 with drawing the valve from its seat. This permits the steam pressure acting on the sur face of condensate in the bucket to force the water to 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 differen tia) pressure (usually 1 psi at least) between the inlet and outlet of the trap in order to Steam Heating Systems 515 bottom of the trap to the outlet of same. Inverted bucket traps are made in sizes from 5 to 3 in., and for pressures varying from vacuum to 2400 psig. Figs. 27 and 28 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 condensate 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. The discharge from flash type traps is intermittent. There are no moving parts in this type of tTap. 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, vulcanizers, kitchen equipment, laundry equipment, evaporators, 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 \ to 3 in., and for pressures varying from vacuum to 450 psig. Fig. 29 illustrates a trap of the flash type. Impulse Traps. These traps are a modification of the flash trap, and depend on the same principle of flash for their operation. In the impulse trap the flashing action HIGH PRESSURE INLET Fig. 29. Flash Trap Fig. 30. Impulse Trap 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 beaters, steam mains, laundry equipment, sterilizers, water and oil heaters and other equipment. This type of trap is particularly suited for use where there are pulsating pressures, such as draining steam lines and separators to reciprocating pumps or engines. It is not influenced by pulsations or wide fluctuations of pressure. Upright bucket traps are obtainable in sizes varying from to 2$ in., and for pressures varying from vacuum to 1200 psig. Fig. 26 illustrates an upright bucket trap. Inverted Bucket Traps. In this type of trap, steam, condensate and air enter the trap under the bell or inverted bucket. Steam floats the inverted bucket and closes the valve. Condensate entering the trap enables the inverted bucket to fall, opening the valve. The condensate then discharges through the open valve until steam again enters and displaces the water contained in the bucket, thus restoring its buoyancyThe Bteam 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 beaters, are usually furnished with a large capacity opening equipped with a bi-metallic thermostatic element which closes when heated by steam, and opens when cooled by air and condensate, allowing air to escape fro the inverted bucket to the trap outlet. Inverted bucket traps are used for draining condensate and air from blast coils, unit heaters, steam drips, laundiy equipn1*.* sterilizers, steam water heaters and other equipment. They are particularly suit for draining condensate from steam lines or equipment where abnormal amounts o* air must be discharged, and where there is also foreign matter such as dirt, sludge an oil draining to the trap. The discharge from inverted bucket traps, like that of upright bucket traps, is intermittent and requires a definite differential PrCSB?E between the inlet and the outlet of the trap in order to lift the condensate from tn Fig. 31. Tilting Trap is utilized to .govern the movement of a valve by causing changes in pressure in a control chamber above the valve. A small portion of condensate, called control now, by-passes 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. . ^hen 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 condensate-vapor mixture restricts the discharge through the center orifice, and therefore the reduced pressure in control chamber builds up, closes the valve, and shuts off all discharge of hot condensate, except the small amount flowing through center orifice. . n ^nc*er normal condensate loads, the valve opens and closes at short intervals under heavy loads, the valve opens wide and the discharge is heavy and 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 25 percent or less than that of the inlet pressure. Impulse traps are made in sizes from $ to 2 in., and for pressures rangmg from one to 600 psig. Fig. 30 illustrates a trap of the impulse type. th Traps. This type of trap as the name implies depends foT its operation on e tilting of the trap receiver. When the receiver is in a horizontal position con- ensate accumulates until the weight of condensate overbalances that of a countere*ght, when the receiver tilts. The tilting action opens the discharge valve, and eam pressure pushes the condensate out of the open discharge valve. When the sewer tank is emptied, except for a slight water seal, the receiver drops back to its 516' CHAPTER 21 1954 Guide Steam Heating Systems 51-7 Fig. 33. Boiler Return Trap or Alternating Receiver Fig. 34. Dripping Main Where It Rises to Higher Level horizontal position and closes the discharge valve, and is again in position to aeeumu-' late condensate. ' Tilting traps are necessarily intermittent in operation, except that once the trap is in the discharge position, it will discharge condensate continuously as long as the, flow of condensate is sufficient to overcome the balance of the counterweight. This type of trap employs packing around the trunnion and valve stem in order to prevent the loss of steam and condensate. Tilting traps are used for draining laundry and dry cleaning equipment, steam cookers, drips from steam mains, steam separators and purifiers and other equipment. They are made in sizes from 1 to 3 in., and for pressures varying from 0 to 250 psig. Fig. 31 illustrates a type of tilting trap which is in use at the present time. Lifting Traps. This type of trap is an adaptation of the upright bucket trap. It has the added feature of an auxiliary pressure inlet through which steam is intro duced 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 Bizes from one to 3 in., and for pressures ranging from vacuum to 150 psig. Fig. 32 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 hold steam, but is an adaptation of the lifting trap. It is used for returning condensate to a low pressure boiler, when due to excess pressure, the condensate cannot flow to the boiler by gravity without flooding the re turn mains, and endangering the boiler by permitting it to go dry. The boiler return trap is a vessel into which condensate alternately collects and is discharged into the boiler by boiler steam pressure. These traps are available in sizes from li to 2} in., and for pressures varying from 0 to 100 psig. A typical boiler return trap is shown in Fig. 33, and a typical connection to a low pressure heating system is indicated in Fig.13. ,. , SteTahme fTorlalopwIinnsgtaglelanteioranlsrules should govern the installation 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 ther- Fig. 35. Looping Main Around Beam Fig. 36. Looping Dry Return Main Arouno Opening Mxe method Pflgwd method Fig: 37. Methods of Taking Branch from Main To find length C-muQSply A by constant for angle B Fig. 38. Constants for Determining Length of Offset Pipe Fig. 39. Dirt Pocket Connection mostatic traps in radiators, convectors and pipe coils. These, in general, are at tached directly to the units without strainers. 2. Whenever it is necessary to maintain in continuous service, apparatus which is to be drained, it is advisable to install a gate valve on each side of the trap, and a valved by-pass around the trap, so that the trap may be removed and repaired and condensate drained through the throttled by-pass 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 pressure on the discharge side 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. Any steam main in any heating system can be elevated if dripped. Fig. 34 shows a connection where the steam main is raised and is drained to a wet-return. If the elevation of the low point is above a dry-return, it may be drained through a trap to the dry-return in two-pipe vapor, vacuum and sub-atmospheric systems. Horizontal steam pipes may also be run over obstructions without a change in level, if a small pipe is carried below the obstruction to care for the condensate (Fig. 35). Horizontal return pipes may be carried past doorways and other ob structions by using the scheme illustrated in Fig. 36. It will be noted that the large pipe, in this case, runs below the obstruction, and the smaller . one over it. Branches from steam mains in one-pipe gravity Bteam systems should use the preferred connection shown in Fig. 37, but where radiator conden sate 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 A ReducingcouptaB TT ^g. 40. Dripping End op Main into Wet Return STEAM MAIN FLOAT AND thermostatic TRAP --------- FLOAT AND THERMOSTATIC TRAP DPT RETURN MAIN DIRT POCKET Fig. 41. Dripping End of Steam Main into Dry Return DRV RETURN MAIN OtRT_ POCKE1 Fig. 42. Dripping Heel of Riser into Dry Return 518 CHAPTER 21 1954 Guide ; giving a perfect swing joint when connected to the vertical riser or radia tor 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. 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 diagonal offset will be found as shown in Fig. 38. Dirt pockets, desirable on all systems employing thermostatic traps, should be so located as to protect the traps from scale and sludge which 3 GATE VMVE SAME SIZE AS TRAP TAPPING high pressure TRAP TO LOW PRESSURE STEAM MAIN WHOLE COUPLING. ' INSIDE PIPE SCREWEO INTO COUPLING AND TANK WELDED BEFORE COUPLING WELDED TO STEEL PLATE HALF COUPLING WELOEO-TO SjDC OF FLASH LEG HIGH PRESSURE CONDENSATE RETURN SAME SIZE AS TRAP TAPPING low pressure TRAP . DIRT POCKET -- SAME SIZE AS,. HIGH PRESSURE return main STEEL FVA7ES WELDED TO PIPE TOP AND BOTTOM see table for thickness 'rrS- \ u wfiT to Exceco ^ 5 FEET to tow pressure! RETURN MAIN ,, I HALF coupling weloed to -- half coupling and gate valve FITTINGS TO BE (2$ LBS. UP TO 60 L&5. PRESS.-4*5>2E Fig. "43. Flash Leg Installation for 80 psi Maximum Steam nr-- Pos'sisTTBF. Con densate ; per Hr.,I Lb at 70 ` Psi Table 13. Dimensions Applying to Fxg^ !1 | I HP Side LP Side |] Flash Bc DE Leg, [Ft. In. In. In. In. IPS 1 F __ 200 | 4 300 700 1600 2500 -1 4000 U 8000 2 15000 21 f 21-801 4 A l31-70| 4 A ;31-70! I A '61-80 1 * .61-80 1} U 61-80 2 A |61-80 24 * 61-80 24 A 0-20, A 9-15: 1,0-15: 4i0-15; 410-15 1AP-15 1*0-15 1A 0-15| 10 12 16 3 6 8 3 1 4 3 3 6 6 8 8 3 3 43 4 ,4 5 6 6 ! i io 10 1i 44 ! t i. 16 6 i6 6 6j 8 12 1 12 14 )1 5 o6 l u 23 H U H u 2 21 3 3 Plat* Thjc*- niens-s- Steam Heating Systems /Runout above floor 5p"R,ser/ Wan line. ...... 1 Jo joint Runout below Hoof PLAN 5195 Fie*-44, .One-Pipe Radiator Connections 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. They are constructed as shown in Fig. 39. On vapor systems where the end of the steam main is dripped down into the wet-retum, the air venting at the end of the main is accomplished by an air vent passing through a thermostatic trap into the dry-return line as shown in Fig. 40. On low -pressure or vacuum systems, the ends of the steam mains are dripped and vented into the return through drip traps opening into the return line. A float and thermostatic type trap is recommended for dripping steam mains and risers as indicated in Figs. 41 and 42. The dripping of high pressure mains, or of equipment using high pressure steam into low pressure or vacuum returns, is generally accomplished by the use of a flagh 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 steam to take place. The low pressure steam therein generated is passed directly to the low pressure steam mains, and the condensate is discharged through a second trap to the 520 CHAPTER 21 1954 Guide; -! Steam Heating Systems 52! Fig. 47. Typical Convector Connections Fig. 48. Typical Connections to ., Finned Pipe Convector low pressure or vacuum return. A typical arrangement of a flash leg, with sizes required for varying capacities, is given in Fig. 43. . CONNECTIONS TO HEATING UNITS Riser, radiator and convector connections must not only be properly pitched at the time they are installed, but must 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 ex pansion or contraction 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 shown in Fig. 44. 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. F,0 Cn!i7nT"L Connections to Finned Tube Blast Heating Coils of the Steam Distributing or Non-Freeze Type Typical two-pipe radiator connections are shown iiy Figs!'45 and 46. 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 connected with top supply and bottom return on the same end. A typical method of connecting convectors is shown in Fig. 47. Some times the supply valve is omitted on convector connections, and a damper is supplied in the outlet grille for heat control: , ... A typical connection for finned pipe convectors is' shown in Fig^ '48. Typical connections to blast heaters are shown in Figs. 49, 50, and 51. Fig. 52 shows atypical return and connection for blast heaters connected to high pressure systems. A typical two-pipe connection to a unit heater is indicated in Fig. 53. 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 Fig. 49. Typical Connections to Finned Fig. 50. Typical Connections to . Tube Blast Heating Coils Arranged Finned Tube Blast Heating Coils; for Series Flow of Air >Arranged for Parallel Flow of Ai.' Fig. 52. Typical Return Connections to Finned Tube Blast Heaters with High Pressure Steam 522 CHAPTER 21 SUPPLY MAIN 1954 Guide/ - Fig 53. Typical Unit : Heater Connections FOR Two-pipe System be used for throttling. Angle globe valves and straight globe valves should be used for throttling in such cases as by-passes around pressure reducing valves or on by-passes around traps. .' REFERENCES 1 A.S.H.V.E. Research Report No. 954--Condensate and Air Return in Steam Heating Systems, by F. C. Houghten and J. L. Blacksbaw (A.S.H.V.E. Transac tio1nPsi,pVeosli.z3e9t,a1b9le3s3, inp. th19is9)c. hapter have been compiled in simplified and condensed form for the convenience of the user; at the same time all of the information contained in previous editions of The Guide has been retained. 3 A.S.H.V.E. Standard Code for Testing and Rating Return Line Low Vacuum Heating Pumps (A.S.H.V.E. Transactions, Vol. 40, 1934, p. 33). CHAPTER 22 HOT WATER HEATING SYSTEMS Available Head; Friction Loss; Classification; System Design; Examples of Piping Design; One-Pipe Gravity, One-Pipe Forced Circulation, Two-Pipe Gravity, and Two-Pipe Forced Circulation Systems, Expansion Tanks, Installation Details, Zoning of Systems A HEATING system is called a hot water system if water is used to convey heat by flowing through pipes connecting a boiler or water heater with radiators, convectors or other suitable heat dispensing means. There are two types: the gravity system in which the water flows by virtue of thermo-syphon action, and the forced system in which a pump, usually driven by an electric motor, sometimes by a steam turbine or other means, maintains the necessary flow. Most panel heating systems (see Chapter 24) fall into the category of forced hot water systems, and the design procedures pertaining to pipe sizing and friction contained in this chapter are largely applicable to such systems. Historically, the gravity system is much the older, and many such sys tems have been in satisfactory operation for several decades. Operation depends on the difference in density of the water due to difference in tem perature in the flow and return pipes. The available head is therefore limited, and the pipes must be ample in size to permit adequate flow of water. In the forced system, the pipes, valves and fittings can be much smaller, with a resultant saving in the cost of installation, since the available head is limited only by consideration of economy in pumping the water. With the forced system, higher boiler temperatures and automatic control of the pump or circulator make possible the use of indirect water heaters with hot water systems when that is desirable. (See Chapter 49.) AVAILABLE CIRCULATION HEAD The available head in a gravity circulation system may be found from the equation: where A. = -------- X 2.31 X 12,000 144 (1) A* = available head per foot of height, milinches (1 milinch = 1/1000 of 1 in. of water). Pi = average density of flow water, pounds per cubic foot. Pi = average density of return, pounds per cubic foot. 144 = square inches per square foot. 2.31 = height of water column equivalent to 1 psi, feet. 12,000 = milinches equivalent of 1 ft of water column. The available head may also be found from Fig. 1. For example, at a "dw temperature of 200 F and a 35 deg drop, and with the mains located ft above the center line of the boiler, the available head is 600 milinches. his is found by following the 200 F flow riser line in Fig. 1 to its intersec- ,IOn with the 165 F return riser line, and then reading, horizontally, a head 523 524 CHAPTER 22 1954 Guide ' of 150 milinches per foot, or 600 milinches for 4 ft. If the first floor radi ators are located 3 ft above the mains, second floor radiators 12 ft above the mains, third floor 21 ft, and fourth floor 30 ft, the heads are 450, 1800, 3150, and 4500 milinches, respectively. In forced circulation systems flow is produced mechanically by means of a pump driven by electricity, steam, or other source of energy. As Hot Water Heating Systems Table 1. Iron and Copper Elbow Equivalents* 525 Fitting Elbow, 90-deg................ Elbow, 45-deg................ Elbow, 90-deg long turn Elbow, welded, 90-deg.. Reduced coupling......... Open return bend......... Open gate valve........... .. Open globe valve........... pipe* (in inches) divided by 12. IHON ^Copper Pipe jTuSING VirriAG Ibojv Ccppr.n Pipe Tubino 1.0 0.7 0.5 0.5 0.4 1.0 0.5 12.0 1.0 0.7 0.5 0.5 0.4 1.0 0.7 17.0 Angle radiator valve........ Radiator or convector . .. Boiler or heater................ Tee, per cent flowing through branch: 100.......... ................ 50.................................. 25..................... 2.0 3.0 3.0 1.8 '4.0 16.0 3.0 4.0 4.0 1.2 4.0 20.0 * Hloe' ne elbl>" equivalent jD feet of pi.pe S_ uids straight pipe equals 25 cfiam Fio. 1. Heads Resulting from Temperature Difference (Gravity Systems) forced circulation velocities are higher than those in gravity systems, and as the friction in a heating system varies almost as the square of the velocity, a given error in the calculation or assumption of the. velocity is less im portant in a forced circulation system than in a gravity circulation systemi and, consequently, it is easier to design a satisfactory forced circulation system than a satisfactory gravity circulation system. ' ` FRICTION LOSS ^ _ Values of friction loss due to flow of water in the various parts of a had ing system must be known in order to design either gravity or forced circu lation systems. The friction loss of fittings is customarily expressed inlequi^' .. ui< 526 CHAPTER 22 1954 Guide Table 2. Heat-Carrying Capacity of Standard Black Pipes 20with Temperature Drop of Deg* , Nominal Pipe Sizes % in, to IS in., and Friction 4 to 800 milinches per fool (A -- Capacity, Mbh. B = Velocity, inches per second) (One milinch equals 0.001 in.) -v. -- -r.-- I Nominal Pipe Size,, Inches TION LOSS PEB Foot of Pipe 4 6 8 10 12 14 16 20 25 30 35 40 50 . 60 70 80 100 150 200 300 400 500 600 800 A B A B A B A B A B A B A B A B A B A B A B A B A B A B A B A B A B A B A B A B A B A B A B A B H Yi 54 0.75 1.35 2.85 1.5 1.7 2.1 1 iw 1H 2 2H 5.4 11.3 17.0 33.0 53.1 2.4 2.9 3.2 3.8 4.3 3mi 5 6 8 ------ - ------ -- -- -- 95 141 197 363 596 1250 2 5.0 5.5 6.0 7.0 7.9 9.6 373102 0.9 1.8 1.7 2.1 3.6 5.75 14.0 21.2 41.3 66.4 2.6 3.0 3.6 4.0 4.7 5.3 119 6.2 176 6.9 248 7.5 456 8.8 748 1570 2 10 12 4690 1.05 2.1 2.0 2.5 4.2 3.0 7.9 16.4 24.8 48.4 77.9 3.5 4.2 .4.7 5.6 6.3 140 7.3 207 8.0 291 8.8 535 10 879 1850 3 12 14 5520 19 1.2 2.4 2.2 2.8 4.7 3.4 8.9 18.6 28.0 54.7 88.1 4.0 4.8 5.3 6.3 7.1 158 8.2 234 9.1 329 9.9 605 12 997 2100 3 13 16 6270 27 1.35 2.45 2.7 3.1 5.2 3.7 9.8 20.5 31.0 60.4 97.4 4.4 5.3 5.9 6.9 7.8 175 9.1 259 10 364 11 671 1100 2320 J 13 15 IS 1.45 2.65 5.65 10.7 22.3 33.7 65.8 2.0 3.4 4.1 4.8 5.7 6.4 7.6 106 8.5 190 9.9 282 11 397 12 731 1200 2530 14 1 20 6950 24 7590 26 1.55 2.85 6.05 11.5 24.0 36.3 70.8 3.1 3.6 4.4 5.1 6.2 6.9 8.1 1.75 3.25 6.85 13.0 27.1 41.0 80.0 3.5 4.1 4.9 5.8 7.0 7.7 9.2 2.0 3.65 7.75 14.7 30.6 46.3 90.5 4.0 4.6 5.6 6.5 7.9 8.8 10 2.2 4.0 8.55 16.2 33.8 51.2 100 4.4 5.1 6.1 7.2 8.7 9.7 11 2.35 4.4 9.3 17.6 36.8 55.7 109 4.7 5.5 6.7 7.9 9.5 11 13 2.55 4.7 10.0 18.9 39.6 59.9 117 6.1 5.9 7.2 8.4 10 11 13 2.85 5.3 n.3 21.4 44.7 67.7 133 5.7 6.7 8.1 9.5 12 13 15 3.15 5.S5 12.4 23.6 49.4 74.9 147 6.3 7.4 8.9 11 13 14 17 114 9.7 129 10 146 12 162 13 176 14 189 15 214 17 238 19 205 11 232 12 263 14 290 15 316 16 341 18 386 20 427 22 303 12 344 13 389 15 430 17 469 18 505 20 572 22 633 25 428 787 1300 2730 13 15 17 21 484 892 1470 3100 15 17 20 24 J3C'S0i 548 1010 1670 3510 6570, 10560 17 19 22 27 32 36 607 1120 1850 3900 7280,111710 18 22 25 30 35 40 661 1220 2010 4250 20 23 27 33 12780 44 712 1320 2170 4580 8570 113780 22 25 29 35 42 47 807 1490 2460 5190 24 29 33 40 115650 54 893 1650 2730 5760 27 32 36 44 17360 3.45 6.35 13.5 25.7 33.8 81.4 6.9 8.0 9.7 11 14 15 3.7 6-8 14.5 27.6 57.9 87.6 7.4 8.6 10 12 15 17 4.15 7.7 16.4 31.1 65.4 99.0 8.3 9.7 12 14 r IS 5.2 9-6 20.4 38. 81. t 12 It 15 h 1 2 2, 6.0 n/ 23.5 45. 95. 1 14 1 1 1 21) 2 > 2 r 7. > 13. ) 29. 56. 5 11 1 18 I> 1i 2 25 3 34 8.7 5 16. 2 34. - 66. 2 14 9 21 2 1 B 2 1 2 5 3<9 3 6 4 9 9.85 18. 3 39. 2 74. 3 156 239 20 23 29 33 4 1 45 10. 9 20. 2 43. 2 82. 5 17 4 26 4 22 2 6 3 2 3 7 4 5 50 12. 7 23. 6 50. 5 96. 5 204 31 0 25 30 3 7 4 3 52 5 9 160 18 172 20 194 22 24C 2 28 3i 35 5 4 41 ~ 48 47 1 54 52 1 60 61 0 70 258 21 278 22 314 25 39C 35 46 3 57 r 45 67 3 54 765 62 84 6 68 99 2 80 465 690 973 1800 2970 6280 24 27 29 35 40 48 500 26 743 29 1050 32 1940 37 3200 43 6770 '12690 20440 52 62 70 _70|566 840 1190 220C 3630 76S0 '*4400,123200 30 33 36 42 4? 59 88 10170< 105( 149C 276( 4561 9650 18120 29220 3* 4 4 5 i 6 74 US83* 41 124C 4i 175( 51 324 ) 62 536( 11350 |21320 j34400 7 87 104 104 ) 51 122(0 64 155 ) 619 182 9 71 219 ) 65 257 9 78 40613 7S 4780 92 673 ) 9) 14270 110 126830 131 143300 146 791 9 10 5 16790 129 131580 154 151000 ' 175 1380 72 2060 80 291 0 88 541 0 10 4 897 9 M9 19040 147 1358401i 57880 174 199 1530 80 1790 94 2280 89 2670 10 4 3220 97 3780 11 4 2215990 9930 21100 [39740 |64210 11 5 132 162 193, [75S703 0 116?0 24820 146780 13 5} 155 191 228 260 * For other temperature drops the pipe capacities ny XSwbv 15 a temperature drop of 30 deg. the capacities shown m this table are to be multiplied b> Hot Water Heating Systems 527 alent number of elbows of the same pipe size which would have the same friction loss. An elbow is assumed to have the same friction loss as a straight pipe having a length equal to 25 diameters (nominal) of the elbow. The resistance of various types of fittings expressed in equivalent elbow resistance is shown in Table I. The friction loss in pipes and tubing may be determined from Fig. 2 and Table 2 for black iron pipes, and from Fig. 3 and Table 3 for type L copper tubing. The scale at bottom of Figs. 2 and 3 is the heat carrying capacity in thousands of Btu per hour based on a 20 deg temperature difference between flow and return risers. In order to use the scale for other than 20 deg difference, refer to footnote under Figs. 2 and 3. , If the flow in a given pipe is calculated in pounds per hour, it may be FLOW OF WATCR IN GALLONS PER MINUTE t ^^er, ?c*^e chart is based on 20 deg temperature difference between flow and return risers, to hnd frmtioD when temperature drop is other than 20 deg , multiply the actual heat conveyed by \actual temp, drop and read the corresponding friction. converted to corresponding gallons per minute by dividing the flow in pounds by 500, after which the friction may be found by entering Figs. * 2 and 3 at the top scale reading which corresponds to the flow in gallons per minute as determined. Orifices drilled in plates inserted in pipe unions are convenient means for introducing friction, where required to balance various circuits. The friction losses caused by various sizes of orifices are given in Table 4. CLASSIFICATION OF SYSTEMS Gravity or forced systems of piping may be classified according to piping arrangement and type of circulation as shown in Table 5. Flow and return main piping (gravity systems) for one-pipe, two-pipe direct return, and two-pipe reversed return systems are shown in Figs. 4, 5, and 6, re- .528 CHAPTER 22 1954 Guide Table 3. Heat-carrying Capacity of Type L Coppeb Tubing with Temperature Drop of 20 Deg* Nominal Tube Sizes \ in. to ^ in., and Friction 60 to 720 milinches per fool. Capacity, Mbh. B = Velocity, inches per second) (One milinch equals Q.QO (A = Miunch Friction Loss per Foot op Tube Sue, In. 56 : r* 1' :m 2 'm 3 354 :4 A B A B A B A B A B A B A B A B A B A B A B A B 720 600 480 360 300 240 180 150 120 90 75 60 8.9 23.6 16.7 27.6 29.0 32.2 43.5 34.6 93 .. 43 160 49 260 56 560 70 1100 89 1650 . 94 2500 105 3600 116 7.8 7.0 20.8 18.6 15.0 13.0 24.8 21.5 26.0 22.5 28.8 25.0 39.0 34.5 31.1 27.5 84 74 39 34 145 128 45 39 240 206 52 45 510 450 64 56 930 820 75 66 1500 1300 85 74 2250 1 2000 94 r 84 3200 2800 103 90 5.9 15.7 11.2 18.5 19.0 21.1 29.0 23-1 63 29 107 33 175 38. 380 47 700 57 1100 62 1750 73 2400 77 5.4 4.7 3.9 14.4 12.5 10.4 10.0 . 8.7 ; 7.5 16.5 14.4 12.4 17.5 15.0 13.0 19.4 16.6 14.4 26.5 -23.0 19.6 21.1 18.3 15.6 57 50 42.5 27 23 20 97 85 73 30 26 22 160 140 118 35 30 . 26 : 340 300 250 42 37 31 630 550 . 470 51 44 38 990 860 730 56 49 41 1500 1320 1100 -63 55 46 2150 1900 1600 69 61 51 3.6 9.6 6.6 10.9 11.5 12.8 17.5 13.9 38 18 65 20 106 23 . 225 28 420 34 650 37 1000 42 1440 46 3.1 8.2 5.6 9.3 10.0 11.1 15.0. 12.0 34 16 57 18 93 20 195 24 370 . 30 565 32 860 35 1250 40 2.7 ` 2.3 2.1 7.2 6.1 5.6 5.0 4.5 3.9 8.3 7.4 6.4 8.5 7.6 6.7 9.4 8.4 7.4 13.0 12.0 10.5 10.4 9.6 8.4 28.5 13 26 23 12 11 48.5 15 44 39 14 12 79 71 62 17 15 13 170 150 133. 21 ; 19 17 310 280 250 25 23 20 480 430 375 27 24 21 730 660 580 31 28 24 1150 950 840 37 31 27 * For other temperature drops the pipe capacities may oe cnangea uis|juuum^;. * temperature drop of 30 deg the capacities shown in this table are to be multiplied by 1.5. --, - spectively. These figures would also illustrate forced circulation if a pump or circulator were shown in the return line at the boiler. One-pipe gravity systems require very precise design owing to the small circulating head available. Also, circulation in them is slow, and tem perature drop is large toward the end of the main, and consequently these systems are usually considered impractical. , One-pipe forced systems compared with gravity systems provide more rapid circulation, with consequent smaller temperature drop in mains and more uniform water temperature in all radiators, and are therefore preferred. Special flow and return fittings are available for improving the circulation to risers. Two-pipe systems have separate flow and return mains. If the return main is direct as shown in Fig. 5 the radiator at the end of the system has R Pi Pi, R F, Pi &T sT" ' q! Fig. 4. One-Pipe System . Fig. 5. A Two-Pipe Direct Return Fig. 6. A Two-Pip Reversed Return Hot Water Heating Systems 529 Diametebof Obzfices (Inches) in Unions ir\~~_in_-m*r-*iicin equa,ls ,, ujuui t.n.). Velocity of Wateb in Pipe in Inches peb Second %-in. Pipe 0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.35 0.40 0.45 0.50 0.55 "'0.60 0.65 1300 650 330 170 2900 1450 740 380 185 5000 11,300 2500 5700 1300 2900 . 660 . 1500 330 . 740 155 350 75 170 20,800 10,400 5200 2600 1300 620 300 32,000 16,000 8000 4000 2000 970 480 45,000 23,000 12,000 6800 2900 1400 700 57,000 28,000 13,000 6500 3200 1600 47rn00` 24,000 12,000 . 5700 2800 53,000. 27.000 13.000 6400 l-in. Pipe 900 2000 460- 1000 270 570 160" " 330 190 3500 ` 1800 1000 580 330 200 120 7800 ' 4000 2300 1400 750 440 ' 260 14,000 7200 4100 2300 1300 800 460 22,000 12,000 6400 3700 2200 1300 720 32,000 17,000 9300 54003000 1800 1100 37,000 21,000 12,000 7000 .4200' 2400 -- 65,000 37,000 22,000 13,000 7400 4300 50,000 28; 000 17,000 10,000 1%-in. Pipe 0.45 0.50 0.55 0.60 0.65 0.70 0.75 . 1000 660 430 280 190 2250 1450 950 630 420 . 285 190 4000 2600 1700 1100 750 510 330 8900 5800 3800 2500 1700 1150! 750 16,000 10,400 6800 4400 3000 2000 1300 25,000 16,400 10,500 6900 4700- 3100 2100 36,000 23,000 15,000 10,000 6700 4500 3000 53,000 34,000 22,000 15,000 10,000 6700 60,000 40,000 27,000 18,000 12,000 60,000 40.000 26.000 0.55 0.60 0.65 0.70 0.75 0.80 0.85 lyfrin. Pipe 850 1900 3300 600 1300 2300 400 850 1500 260 600 1100 400 760 300 540 380 7400 5400 3600 2600 1800 1200 860 13,000 8600 7200 4400 3000 2200 1600 21,000 16,800 10,400 7000 5000 3200 2300 30,000 21,000 14,000 10,000 7000 5000 3000 50,000 30,000 21,000 14,000 10,200 7800 53,000 39,000 28,000 19,000 13,000 45,000 30,000 2-in. Pipe 0.70 0.80 0.90 1.00 1.10 1.20 1.30 890 470' 255 . 160., 1850 975 560 : 340 214 3500 1800 1000 610 375' 195 7400 3900 2200 1320 850 460 275 14,000 7400 4200 2520 1600 950 525 22,300 11,700 6500 4000 2500 1360 980 33,000 17,000 9500 5800 3700 1910 1375 37.000 20,500 12,500 7000 4200 3100 38,000^ 23,000 14,000 8100 4400. 49,000: 30,000 16,800 8850 . smaller i ______ _______ ___ , *Tj-m. buu 4*m. pipe were calculated from those in the . r Pipes, the calculations being based on the assumption that, for any given velocity, the loss of head *\-ctioQ * ratio of the diameter of the pipe to that of the orifice* This had been found to be prao- b hi*1116 tk0 *e8*s 40 determine the losses of head in orifices in %-\n., 1-in., and iK-in. pipe, conducted he Texas Engineering Experiment Station, and also in the tests to determine the losses of head in ori- in 4-in.# 6-in,, and 12-in. pipe, conducted by the Engineering Experiment Station of the University oj ynoi*t (Bulletin 109, Table 8, p. 38, Davis and Jordan). . 530 CHAPTER 22 1954 Guide the longest supply and longest return piping. The lengths of circuits to the various radiators may be equalized by using a reversed return main (see Fig. 6). In some cases reversed return mains require no more piping than direct return systems. With gravity circulation and direct return piping it is necessary to design the longest circuit for the available circulating head, and to obtain the same resistance in all other circuits by proper selection of pipe sizes, by addition of fittings, or by use of orifices. When a reversed return system is used, it is usually found that very little adjustment is required to attain uniform distribution to all radiators. Forced circulation in two-pipe systems, because of increased available circulating head, permits design for higher velocities with a consequent reduction in pipe sizes. The increased velocity also shortens the heating-up period and facilitates control of circulation. Reversed return mains are also advantageous in forced circulation systems, in equalizing piping re sistance to all heating units. Table 5. Classification of Hot Wateb Heating Systems Piping Arrangement One-Pipe Two-Pipe Direct Return Two-Pipe Reversed Return Type op Circulation Gravity Forced Gravity Forced Gravity Forced Expansion Take Open Open Closed Closed Open Closed Open . Closed Open Closed Open Closed PIPING SYSTEM DESIGN In designing hot water heating systems certain assumptions are usually made for the purpose of simplification as follows: . 1. Water temperature drop is assumed to be 30 to 35 deg for gravity systems and 20 deg for forced circulation systems. These values usually result in economical design but, particularly in large forced circulation systems, it is necessary to take into account the cost of pumping the water required at various velocities in relation to the annual charges in the capital cost of the system. 2. Water velocities in forced systems in excess of 4 fps in piping of \\i in. I. D. or less are likely to cause disturbing noises in residences. In factories or in instal lations having larger pipe sizes, velocities as high as 8 or 8.5 fps are not uncommon. 3. Design outlet water temperatures in gravity systems are generally selected be= tween 140 and 200 F (with the average approximately 180 F); while forced circulation design temperatures vary from 170 to 220 F, although higher temperatures can be used if the pressure in the system corresponds. 4. For forced circulation systems, the allowable friction loss, which is based upon the available circulating head, is determined partially by the characteristics of th'e pumps available. 5. Forced hot water system friction should usually be held between 600 and 250 milinches per foot. Above 600 milinches high velocities would be encountered, and below 250 milinches circulation would become too slow, so that much of the rapid response expected from forced circulation would be lost. ~ Hot Water Heating Systems 531 The water to be circulated is where ` W = H/{C A t) (2) . W = weight of water, pounds per hour [gallons per minute = 11/(8 X 60)]. H = heat required, Btu per hour. C = specific heat of water (-- 1). At = drop in temperature between supply and return, Fahrenheit degrees. The following graded series of examples of the design of hot water piping systems will illustrate the fundamental principles and methods. The differences between reversed return and direct return systems are shown, and the methods of balancing the several radiators or circuits are illustrated. A simple gravity system is shown in Fig. 7, and an elementary forced circu lation system is diagrammed in Fig. 8. Fig. 7. Gravity System Fig. 8. Forced Cir culation System Elementary Gravity System Fig. 9. Determina tion of Required Temperature Difference Example 1: A simple gravity-circulation system is illustrated in Fig. 7 with one radiator that is giving off heat at the rate of 20,000 Btu per hr or 20 Mbh. The boiler imparts heat to the water at the same rate, and the water circulates at a uniform Velocity. This uniform velocity is such that the friction of the circuit is equal to the head developed by the difference in density between the supply and return water and the height of the system. The circuit consists of 1 boiler, 1 radiator, 2 ells, 1 radiator valve and a total of 24 ft of pipe. Solution: With the average water temperatures of 200 and 180 F in the supply and return risers, respectively, the head will be 90 milinches per foot of water column. This head may be found from Fig. 1. Since the center of the radiator is 10 ft above the center of the boiler, the total head of the circuit is 10 x 90, or 900 milinches, or 0.9 in. of 190 F water. The friction of the circuit must then also be 900 milinches. The friction of 1 ft of 1 in. pipe is found from Fig. 2 to be about 46 milinches at 20 Mbh, and the corresponding velocity 9 in. per second. Note that all values in Fig. 2 are based on a temperature difference of 20 deg. . Similarly, if a 11 in. pipe were to be used, the friction head would be about 12 milinches per foot, and the corresponding velocity about 5 in. per second, from Fig. 2. To find the friction in the elbows, boiler, radiator, and valve, Table 1 is used, and jhe entire circuit is found to be equal to 10 elbow-equivalents plus 24 ft of pipe, kjjch elbow-equivalent is equal to a pipe length of 25 times the nominal diameter. Then the equivalent lengths of straight pipe are 45 ft of 1 in. pipe or 50 ft of 1} in. Plp2e*3 4I5n many cases, it is sufficiently accurate to add 50 percent to the total pipe length to correct for resistance of fittings. . Hence, if 1 in. pipe is used, the friction of the circuit will be 45 X 46, or 2070 mil- 1954 Guide CHAPTER 22 532 inches, and if 11 in. pipe is UBed, the friction will be 50 X 12, or 600 milinches. A 1 in. pipe would, therefore, be too small and a 1} in. pipe too large to permit the desired circulation with a flow-return temperature difference of 20 deg. / If the circuit is of 1 in. pipe, the circulation will take place with a temperature difference greater than 20 deg, and if the circuit is of it in. pipe, the circulation will take place with a temperature difference smaller than 20 deg. To find, for example, the temperature difference at which a circuit of 1 in. pipe would transmit the required 20 Mbh, assume the difference to be 40 deg. From Fig. 1, the head available for producing circulation would be 175 milinches per foot, or 1750 for the system, for a temperature drop from 200 to160 F. The fric tion of the system may be found from Fig. 2; the chart of this figure is based on a tem perature difference of 20 deg; if the temperature difference were 40 deg, the heat conveyed would be twice that shown in the chart. Hence, find 10 Mbh on the lower scale, proceed vertically upward to the intersection with the 1 in. line, and from there to the left scale read 13 milinches per foot. Note that the velocity would then be only about 5 in. per second. The total friction would then be 45 X 13 or585 milinches: Since the head would be 1750, circulation would take place with a temperature differ ence less than 40 deg. The required temperature difference may be determined by constructing the diagram of Fig. 9, from which it appears that the temperature differ ence with which the 1 in. pipe circuit would function is about 30 deg. Hence, if the Fig. 10. One-Pipe Gravity Circulation Fig. 11. One-Pipe Forced Circulation System (Example 3) System (Example 4) flow riser temperature is 200, the return riser temperature will be 170, and the average water temperature in the radiator about 185 F. Elementary Forced Circulation System _ Example 8: Design a system for the piping arrangement shown in Fig. 8, accord ingto one of the outlined procedures. The procedure may be as follows: Assume the head developed by the circulating pump and the pipe size and, find the flow-return temperature difference; or, assume the head developed by the pump and the flowreturn temperature difference, and find the pipe size; or, assume the pipe size and the^ flow-return temperature difference, and find the head which the circulating pump muSstodluetvioenlo: pA. ssume that the circulating pump will develop a head of 2 ft or 24,000 milinches and that a 1 in. pipe is to be used. The equivalent length of the circuit wul then be 45 ft, as in Fig. 7, and the available head will be 24,000/45, or 533 milinches per foot. In Fig. 2, find 533 on the left scale, move horizontally to the intersection with the 1 in. pipe line, and read about 77 Mbh delivered by the pipe (with a velocity of about 35 in. per second) for a temperature difference of 20 deg. Since the circuit is to deliver only 20 Mbh, the temperature difference will be 20 divided by 77 and multiplied by 20, or 5.2 deg, Hence, if the flow riser temperature is 200, the return riser temperature will be about 195, and the average water temperature in the radia torIafbaoiuitn1.9p7i.p5eFw.ere used instead of a 1 in., the equivalent length of circuit would he 35 ft instead of 45; the unit head, 686 milinches instead of 533; the velocity, 27 in. Per Hot Water Heating Systems 533 second instead of 35; the temperature difference, 19.5 instead of 5.2; and the average water temperature in the radiator, about 190.5 instead of 197.5 F. . If the 1 in. pipe is used for the circuit, the gravity head will be 22 milinches per foot, or 220 for the circuit (Fig. 1, 200 to 195). Since this is only 1 percent of the pump head (24,000 milinches), it may be neglected in the calculation, as was done previously. However, there are cases in which the gravity head is so large compared with the pump head that it should be included in the calculation. The methods just described for the design of the two elementary systems are fundamental, and apply to the design of all hot water heating systems. In every system, however large and complicated, the pipe system must be such that the head forcing the water from the boiler to any one radiator is equal to the friction in that radiator's circuit when the radiator is receiving its proper quantity of hot water, and the system is functioning at a steady rate. ; . ,. Other examples illustrating design of various systems follow. One-Pipe Gravity Circulation System Example S: Select pipe sizes for the one-pipe gravity system having a total load of 67,500 Btu, shown in Fig. 10. Assume: flow temperature 190 F, return temperature 160 F, mains 5 ft above datum plane of boiler, center plane of radiators 4 ft above the mains, length of main.IQO ft. ' . : Solution: From Fig. 1 the available circulating head for 190 F flow and 160 F return temperature is 126 milinches per' foot of height. The available circulating head for design of the main is therefore 5 X 126 = 630 milinches. The measured length of main, plus 50 percent added for resistance of fittings, equals 150 ft equiva lent length. The main can then be designed for a friction loss of 630 + 150 = 4 milinches per foot. From Table 2 at 4 milinch friction loss, a 2 in. pipe will supply 33 Mbh and a 2) in. pipe will supply 53.1 Mbh at 20 deg drop. This is equivalent at 30 deg drop to 49.5 Mbh for 2 in., and 79.6 Mbh for 2) in.-pipe. A 2\ in. main will therefore be selected, and the pressure drop will be somewhat less than .4 milinches per foot. The piping from main to radiators is sized in a similar manner. Assume that water reaches point B, Fig. 10, at 190 F and has a 30 deg drop in the radiator circuit. From Fig. 1 the available head is 126 milinches per foot of height or a total of 4 X 126 = 504 milinches for the circuit (with the radiator 4 ft above the main). The measured length of piping is 11 ft and the fittings add 14 elbow equivalents (which would be equivalent to 22 ft if the pipe size is assumed to be i in.); the equiva lent length is therefore 33 ft. The circuit can therefore be designed for a friction loss of 504 -5- 33 = 15 milinches per foot. From Table 2 by interpolation a } in. pipe would supply 5.85 Mbh at 20 deg drop or 8.78 Mbh at 30 deg drop. Since the load is 9 Mbh, the | in. size will be satisfactory. The remaining radiator circuits may be sized in a similar manner. Allowance should be ma.de in one-pipe gravity systems for the drop in temperature.which occurs in the supply main as the cooler water returns from the radiators. The drop will be in the same proportion to the total drop of 30 deg as the load supplied to any point in the main bears to the total system load, e.g., the temperature at D will be 190 -- (gpaOO X 30^ = 186 F. At point F the temperature will be 190 -- ^^G0C^H^10,500 ^ 3<>) = 181 F. One-Pipe Forced Circulation System Example 4: Select pipe sizes for the one-pipe forced circulation system having a joad of 67,500 Btu shown in Fig. 11. Assume a water temperature drop of 20 deg. Ihe water temperature does not affect the size of piping, but does affect the radiator 8izes required. Solution: The water to be circulated at 20 deg drop will be 67,500 + 20 = 3375 `bperhourorgW! = 7gpm. . By reference to manufacturers' pump capacity charts (typical example, Fig. 12), 534 CHAPTER 22 1954 Guide it wiii be found that a 1 in. pump will deliver 7 gpm against a head of 4 ft (54,000) milinches). , Since the main from A to 0 has an equivalent length of 150 ft (100 ft actual length plus 50 percent added for friction loss in fittings), the main may be sized for 54,000/150 = 360 milinches per foot. From Table 2 by interpolation at 360 milinches friction loss and at 20 deg drop, a 1 in. pipe would supply 62,600 Btu per hour, and a 1* in. pipe would supply 131,600. Since the 1 in. pipe is too small, a in. pipe will be used. Since the li in. pipe offers less than 360 milinches resistance per foot, the velocity of water will increase until the output of the pump and the friction loss are in equi librium at some point on the pump performance curve, for instance, at 10 gpm and a head of 4 ft or 48,000 -s- 150 * 320 milinches per foot of pipe. The friction loss in the main between flow and return connections to radiators will be assumed to be 320 mil- inches per foot. . In determining sizes for the piping from the main to any radiator, the resistance in the radiator circuit such as B-C (which has a load of 9 Mbh) is made equal to the Fia. 12. Performance Chart for Circulating Pump resistance in the main from B to C which, if there are 3 ft of main between connec tions, is 3 X 320 = 960 milinches. If the total equivalent length of the radiator cir cuit determined by use of Table 1 is 32 ft, the radiator circuit B-C will be sized for a friction loss of 960 + 32 = 30 milinches per foot, for which in Table 2 a f in. pipe is found to supply 8550 Btu per hr, and will be considered ample. Other radiator circuits such as D-E, F-G, etc., can be sized in a similar manner. Two-Pipe Gravity System (with Reversed Return) Example 5: Select pipe sizes for the two-pipe gravity system shown in Fig. 13The center plane of the highest radiator is 8 ft above the center plane of the boiler. Assume a 180 F flow temperature and a 150 F return temperature. Solution: The piping should be sized so that the frictional resistance at the de sired rate of flow is equal to the available circulating head. From Fig. 1 at 180 F flow and 150 F return temperature, the available head is US milinches per foot of height or 8 X 118 = 944 milinches total for the highest radiator. The longest circuit from boiler to radiator and back to boiler must therefore have a resistance of 944 milinches. The longest circuit (see Fig. 13) is A-D + D-H + II'*' containing 38 ft of pipe and, if 50 percent is added for equivalent length of fitting?, the equivalent length is 57 ft. Hot Water Heating Systems 535 The circuit should then be designed for a friction loss of 944 + 57 = 16 milinches per foot (approximately). The pipe size may be found from Table 2 at 16 milinches per foot, but since the temperature drop is 30 deg, find pipe size corresponding to 20/30 of actual load for each section as follows: Section A-B B-C C-D D-E E-F Load Mbh Size of Pipe fob 16 Milinches per Foot Section 58 Hi G-H 31 20 H4 H-K 154 K-L 16 1 L-M 6 54 M-N Load Mbh Size of Pife fob 16 Milinches per Foot 11 'm 19 25 114 31 U4 58 1H Piping to the radiators may be sized from Table 2 for the same resistance, 16 mil- inches per foot, but since the temperature drop is 30 deg, find pipe size corresponding to 20/30 of actual load for each section as follows: Radiator.................................................. Load, Mbh........................................... Pipe size. In......................... :........... %\ 11 1 *2 8 $ #3 6 1 #4 *5 6 24 1U #6 3 i A hot water heating system will adjust its rate of flow until the friction loss bal ances the available head. It is therefore self-correcting in regard to small errors made in selection-of-pipe sizes. Two-Pipe Forced Circulation System Example 6: Select pipe sizes for the two-pipe forced circulation reversed return system having a total load of 159 Mbh shown in Fig. 14. Assume a difference of 20 deg in supply and return water temperature. The total equivalent length of the longest circuit is 180 ft. The gravity circulating head due to difference in temper ature may be disregarded in design. Solution: The water to be circulated is 159,000 -* 20 7950 lb per hr or 79~5--0x = 16.5 gpm. From a pump performance chart such as Fig. 12 it is foun d thOaUt X16.o5 gpm will be delivered by a 1 in. pump against a 3 ft head (36,000 milinches) or a ljin. pump against a 4.5 head (54,000 milinches). The longest circuit, including the supply and return main and the longest radiator circuit, is 120 ft and, if 50 percent is added for friction loss in fittings, the equivalent length is 180 ft. If the 1 in. pump is used, the piping will be sized for 36,000/180 = 200 milinches per foot, resulting in selection from Table 2 of a 2 in. main for the Section A-B which supplies 159 Mbh. The large difference in pump and main size, as well as the low velocity resulting from the 200 milinch per foot friction loss, indicates that the li in. pump should be considered. The design friction loss, if the 11 in. pump is used, can be 54,000/180 = 300 milinches per foot and, at this friction loss, Table 2 will indi cate the pipe sizes for the various sections in Fig. 14 as follows: Section A-B B-C C-D D-E E-F F-G g-h Supply Mbh 159 91 75 63 49 37 .6 Pipe Size, In. 1V4 1W m r, 54 | Section J-K K-L L-M M-N N-0 O-P P-Q Return Mbh 16 28 42 54 75 91 159 Pipe Size, In. ?i X I 1 1H m fooT^sinf^blt"^'ZZtS be 8iZCd fr the Same friCtiU ,0SS' 300 P- Radiator_ ^d. Mbh.! ............... #1 #2 #3 *4 .................................. 16 12 14 12 size, In ............... i i circuit divider, use l ia. branch to #5 and $ in. to #6 radiator. *5 and 06 #7 21 16 i i CHAPTER 22 1954 Guide 536 EXPANSION TANKS Water heated from 40 F to 200 F expands about 0.04 of the original volume. The expansion tank permits the change in volume of the water in the heating system to take place without producing Undesirable stresses due to pressure in any part of the system. Expansion tanks may be open, as illustrated in Fig. 15, or closed as shown in Fig. 16. An open expansion tank has free vent to the atmosphere and consequently, the pressure on the surface of the water is always that of one atmosphere. The minimum contents of an open tank should be 0.06 of the volume of the water in the system including that in the boiler, heat transmitters, pipes, etc. This capacity is 50 percent in excess of the actual increase in volume of water ve>rr GAGE/^1 GLASS TANK '-----7B drain VALVE--' * RETURN overflow PIPE EXPANSION tank WATER-*' PILL / CHECK VALVE / FILL VALVE VALVE OPEN except WHEN .draining TANK rh expansion PIPE TO , INSIDE CIRCULATING SEVVER PIPE DRA|N / PUMP-LOCATE IN POSITION RECOMMENDED BY MANUFACTURER * Fin.15 An Open Expansion Tank 16Fig. A Goosed Expansion tank Hot Water Heating Systems 537 due to increase in temperature from 40 F to 200 F. The tank should be located at least 3 ft above the highest radiator. Provision must be made to prevent freezing of the water in the tank as well as in the pipe leading to the tank. In accordance with Paragraph H-92 of the ASME Low Pressure Heating Boiler Code 1946: "All hot water heating systems shall be so in stalled that there will be no opportunity for the fluid relief column to freeze or to be accidentally shut off. If the system is equipped with an open expansion tank, an internal over-flow from the upper portion of the expansion tank must be provided in addition to an open vent, the internal over-flow to be carried within the building to a suitable plumbing fixture or to the basement." (See Fig. 15.) When the vent from an open expansion tank is extended through the roof, it should be not less than 4 in. in diameter from a point below the roof, through and beyond the roof line. This will prevent vapor, which sometimes rises from an expansion tank, from closing the vent during outside freezing temperatures. .: In a gravity circulation system,, the pipe to the open expansion tank should be connected to the supply riser from the boiler, so that the air liberated from the. water in the boiler will enter the expansion tank. In a forced circulation system, the pipe to an open expansion tank should be connected on the suction side of the circulating pump. . A closed expansion lank is sealed against free venting to the atmosphere. The tank may be above the highest radiator or heat transmitter, or may be below the lowest, one. The minimum contents of a closed expansion tank must be such that the expansion of the water due to increase in temperature will be cushioned against a reservoir of compressed air above the water level in the expansion tank. The tank must provide space not only for the change in water volume, but also for variations in air volume within the tank due to changes in air pressure. If the closed expansion tank is below the heat transmitters, the tank should be larger than if it is above them, and the higher the building, under such circumstances, the larger should be the air capacity in excess of that required for increase in water ' volume due to temperature rise. The size of an expansion tank for installation in a closed system may be determined by the following formula: . P, + 0.434H Pt where V = required tank capacity, gallons. E = expansion of water from cold system to flow riser temperature, gallons. Pi = atmospheric pressure, psia. -. P-. = maximum tank pressure specified for heated system, psia. E = height of top of filled system above tank, feet. (Note: Top of system open to atmosphere when system is filled.) Example 7: Select a closed expansion tank for basement installation on a system TMaing 5000 gal and operating at 200 F flow temperature. The static head, due to e height of the system, is 70 ft. The maximum pressure should not exceed 100 psig. Solution: Assume that the system is filled at 40 F. Then 538 CHAPTER 22 1954 Guide E = 0.04 X 5000 = 200 gal. Pi = 14.7 psia P, = 100 + 14.7 = 114.7 psia. Substituting these values in Equation 3, 200 200 V= 14.7 = 1000 gal. 14.7 0.327 - 0.128 14.7 + 0.434 (70) 114.7 The size of a basement-located closed expansion tank should be at least equal to the following: One story buildings: x = 0.10 V Three story buildings: x -- 0.17 V Two story buildings: x = 0.13 V Four story buildings: x -- 0.23 V where x -- expansion tank size in gallons. V = water volume in heating system in gallons. This condition favors, especially in tall buildings, the placing of the closed expansion tank above the highest heat transmitter. ASMETable 6. Requibed Size op Closed Expansion Tank Sq Ft of Equivalent Direct Radiation Installed Gallon Tank Sq Ft of Equivalent Direct Radiation Installed Gallon Tank Up to 350 Up to 450 Up to 650 Up to 900 Up to 1100 - . 18 21 24 30 35 Up to 1400 Up to 1500 Up to 1800 Up to 2000 Up to 2400 . 40 2--30 2--30 2--35 2--40 For systems with more than 2400 sq ft of installed equivalent direct water radiation, the required capac ity of the cushion tank shall be increased on the basis of one gallon tank capacity per 33 sq ft of additional equivalent direct radiation. .. It is common practice to use multiple tank installations on large systems, in lieu of one tank, the required capacity of which would be beyond commer cially available sizes. s Any closed expansion tank located above the heat transmitters of a hot water heating system should be connected by a direct pipe with the flow main leaving the boiler, in order to enable the air to pass easily to the ex pansion tank. In a closed hot water heating system the water under pres sure tends to absorb air at a rate increasing with pressure increase and decreasing with temperature increase. Means must be provided to adjust and to observe the proportion of air within any closed expansion tank. This involves the provision of an air inlet valve, a water gage, and a relief valve. A source of supply of com pressed air for renewing the air cushion is highly desirable, especially in large, high pressure, hot water heating systems where it is "inconvenient, if not impracticable, to drain down the water in the system so as to permit introduction of atmospheric pressure air. In smaller installations, gage fittings on the tank are usually omitted in order to prevent air loss from the tank. Occasional inspection of the tank or the necessity of adding water to the system will then indicate whether air should be added to the tank. The ASMS Low Pressure Heating Boiler Code 1946, in paragraph H-92, specifies that provision must be made for draining a closed expansion Hot Water Heating Systems 539 tank without emptying the system. The Code also specifies the minimum sizes of closed expansion tanks based upon the equivalent direct radiation installed. (See Table 6.) For every hot water heating system, the designer should calculate the volume of water contained in the radiators, piping system, boiler, etc., in order to select the proper size of expansion tank. The water content of the piping can be obtained from Table 7. For a rough selection of size, however, it is sometimes assumed that 50 percent of the volume of water is contained in the radiators, and that the water content per square foot of radiator heating surface is 0.2 gal for column radiators, and 0.13 gal for tube type radiators. Another rough method for determining the size of an expansion tank to be located above the highest radiator, is to divide the square feet of radiation by the factor 40 to obtain the required capacity in gallons of the tank. INSTALLATION DETAILS Items that should be considered in the design of piping for a hot water system are: All piping must be so pitched that all air in the system can be vented either through an open expansion tank, radiators or automatic relief valves. When piping must be ' Table 7. Volume of Wateb in Standabd Pipe Pips Size, In. a Lineal Ft of Pipe Containing 1 Gal 63.1 36.1 22.2 12.8 9.47 Pipe Sub, | In. 2 !* 4 5 6 Lineal Ft op Pipe Containing 1 Gal 5.75 4.02 2.60 1.52 0.96 0.67 > uu arouna an ODStacie such as a beam, it is advisable to drop the piping below the beam. If looped over the beam, it becomes necessary to provide for venting of air from the high point of the pipe. When changing the size of horizontal runs of pipe, eccentric fittings should be used to keep the tops of the pipes in line to permit free passage of air along the pipe. . All piping must be arranged so that the entire system can be drained. Sections of piping individually valved shall have corresponding drain valves. In large buildings, the piping may be zoned according to exposure of building, usage of building, or method of control. All piping must be installed so that it is free to expand and contract with changes of temperature without producing undue stresses in the pipes or connections. For this purpose it is generally sufficient to allow for a variation in length of I in. for 100 ft of pipe. The pipe system should be designed so that each circuit has its correct friction for balanced water distribution. This may be done by change of pipe size or change in piping detail. The connections from the boiler to the mains should be short and direct, to reduce the friction, and should allow for expansion. The mains and branches should pitch up and away from the heater, generally not less than 1 in. in 10 ft. _ . The connections from mains to branches and to risers should be such that circulabon through the risers will start in the right direction. Hence, in a one-pipe system the flow connection must be nearer the heater than the return connection. In a correctly-designed two-pipe system, the pressure in the flow main is higher than that m the return main, and a slight variation in the distances of the flow and return con nections from the heater is not material; but it is generally best to have the two connections about equally distant from the heater. _ . Generally, connections to risers or radiators are taken out of the top of mains at either 45 or 90 deg from the horizontal plane. .Supply connections are usually made at the bottom of radiators so that circulation W*H not be stopped by accumulation of air, as would be the case with a top supply CHAPTER 22 1954 .Guide 540 Fig. 17. Vertical Zoning of Hot Water Heating System in a 12-Story Building (Provision should be made for expansion in each closed circuit.) connection. Short radiators are sometimes connected for top supply and bottom re turn on the same end. When so connected, attention must be given to venting of air from the top of the radiator somewhat oftener than when bottom connections are useUdn. less used as heating surface, all piping, both flow a nd return, should be insu llaotceAadtle.l dlasrgoethsaysttepmarstsshoofutlhdebseypstreomvidmedaywbitehiseoxltartaedstofopr and drain valves, suitably repairs without making it necessary, to drain the water from the entire system. Relief.Value. The ASME Low Pressure Heating Boiler Code requires that all hot water heating boilers shall be equipped with a tested and rated relief valve having adequate capacity to match the gross output of the boiler. In order to comply with the requirement, relief valves must be connected to the top of the boiler and a discharge pipe must be connected to the relief valve and so arranged that there will be no danger of scalding attendants. The proper location of the relief valve is shown in Fig. 16. ZONING In large hot water -systems, improved control and economy can. be achieved by separating the systems into sections or zones (vertical or honzontal) which can be operated independently of each other. Variations in heat requirement of the different zones, as influenced by the exposure of the building, solar heat, weather conditions, heat from processes, type of occupancy, building chimney effect, etc., can readily be compensated for when heat can be supplied only where needed. ' In tall buildings, vertical zoning such as shown in Fig. 17 not only pro vides the advantages of control and economy, but also reduces the water pressure in the system to that caused only by the number of floors served by each section. As shown in Fig. 17 a steam boiler can conveniently be used to supply steam to the heat exchangers supplying heated water to each zone. CHAPTER. 25 RADIATORS AND CONVECTORS Heat Emission of Radiators and Convectors, Radiators, Convectors, Ratings of Radiators and Convectors, Effect of Operating Conditions, Heating Effect, Heating Radiators and Convectors, Enclosed Radiators RADIATORS and convectors are heat emitting units used in steam and hot water heating systems for supplying heat by radiation and convection to a room. The function of any radiator or similar device is the maintenance of occupancy comfort through the control of the mean radiant and air temperatures in the area. Since heat losses through the various parts of the structure constantly tend to lower these temperatures below the comfort point, the radiator or convector should be so placed and regulated that its output will replace the losses when and where they occur. If 80 percent of the room heat loss occurs through a cold wall or window area, then 80 percent of the input should be introduced in or directed toward that area. . The term radiator refers to a unit which emits a large part of its heat by radiation and includes cast-iron radiators, baseboard radiation and pipe coils. Cast-iron radiator types may be column, large-tube,. small- tube or wall. Baseboard radiators may be of the radiant cast-iron type, radiant-convector cast-iron type, or finned-tube type. The last type, how ever, is actually a convector. . The term convector refers to a unit which emits the greater portion of its heat by convection. It includes such units as conventional convectors in which a heat emitting element of either cast-iron or of the finned-tube type is enclosed in a cabinet, but may also be of the unenclosed finned- tube type. HEAT EMISSION OF RADIATORS AND CONVECTORS Most heating units emit heat by radiation and convection. An exposed radiator emits roughly half of its heat by radiation, the amount depending upon the size and number of sections. In general, a thin radiator, such as a wall radiator, emits a larger proportion of its heat by radiation than does a thick radiator. When a radiator is enclosed or shielded, the propor tion of heat emitted by radiation is reduced. The balance of the emis sion occurs by conduction to the air in contact with the heating surface, and this heated air rises by circulation due to convection, and transmits this warm air to the space which is to be .heated. Convectors transfer the smaller proportion of their heat to the room by radiation. Since most of their heat is transferred by convection, the heat omission is dependent upon the vertical distance between the heating ele ment and the outlet grille at the top of the convector cabinet. . The output of a radiator or convector can be measured only by the heat it emits and is generally expressed in units of: Btu per hr; Mbh (1000 Btu per hr); or in equivalent direct radiation (e.g., 240 Btu per hr for steam). 542 CHAPTER 23 1954 Guide Table 1. Column-Type Cast-Iron Radiator Generally Accepted Rating per Section* Height Inches One Column Sq Ft Btu/hr - Two Column Sq Ft Btu/hr Three Column ' Sq Ft Btu/hr 15 m 360 2* 540 20 22 23 1H . 360 2 2)4 480 540 3 1M 400 2)5 560 720 26 32 38 45 2 ' 480 2H 600 3 720 2H 3)4 4 5 640 800 960 1200 . 3N 4)4 5 6 900 1080 1200 1440 Four Column Five Column Six column Sq Ft Btu/hr . Sq Ft Btu/hr Sq Ft 1 Btu/hr 13 16 18 20 22 . 32 38 45 3 720 3)4 900 ' 3 720 4H 1120 4)4 1080 1200 4 960 5 1200 7 1560 8 1920 10 10 2400 1680 2400 ' tors* Texhpeosseerdatiinngas naorermbaalsmedanonnesrt;enaomt atot r2a1d5 iaFtoarnsdinasitraallet dVUberh.indi neenycloaspuprelys, oguriilylesw, ormuanudueicrushelves. For Btu per hour ratings at other temperatures, divide table values by factors found in Table 6. .' Table 2. Large-Tube Cast-Iron Radiator's * Sectional, cast-iron, tubular-type radiators of the large-tube pattern, that is, having tubes approximately it 9i in. on ranters. Number or Tubes per Section Catalog Rating per Section* Sq Ft Btu/hr Height In. 1H 420 20 2 480 23 2)4 560 26 3 720 3W 840 38 2)4 540 20 2)4 600 23 4 2)4 660 26 3)4 840 4)4 1020 38 2)4 640 3 720 3)4 840 4)4 1040 5 1200 20 23 26 38 3 720 3)4 840 660 1200 6 1440 20 23 26 32 38 2)4 600 14 720 17 3)4 880 20 * These ratings are based on steam at 215 F and air at tors exposed in a normal manner; not to radiators installed 70 F. They apply behind enclosures, gornillleys,tobrinusntadueer ush*e-lv--es- For Btu per hour ratings at other temperatures, divide table values by factors found in Table 6. *" WMhaexriemgurmeaatesrsethmabnlys6ta0nsdeacrtidonlesg. hLeeignhgttshaerqeuraelqsuniruemd,bethrisofdsimecetinosnisontimsheasll2b\ ein6. in., except for 77*ttu.hj*e sections, in heights from 13 to 20 in., inclusive, for which this dimension shall be 4) in. Radiators may 00 furnished without legs. ' d For 5-tube hoepital-type radiation, this dimension is 3 in Radiators and Convectors 543 Table 3. Small-Tube Cast-Iron Radiators Nouber or Tubes per Section 3d 4d 5d 6d Rating PER Section* Sq Ft Btu/hr 1.6 1.6 1.8 2.0 2.1 _ 2.4 2.3 3.0 3.7 "384 384 432 480 504 576 552 720 888 Section Dimensions A Height0 B Width Minimum Maximum C Spacing1* In. In." In. In. 25 3)4 3)4 IM 19 22 25 4Me 4Me 4N 41M* 4*)i 1)4 1)4 1)4 22 25 5)4 6Ne 1)4 5)4 6M# IN 19 6'N 8 25 6*N# 8 32 6N 8 IN IN IN D Leg Height0 In. 2)4 2)4 2)4 2)4 2)4 2)4 i mill tors exposed in a ,,nor_m__a__l _m_ ra~nn..e..r;anmo.tu.tovradialrerstsuinasatairlleads btoehfin. d enncelyosaurpepsl,y gorinllelys,toor inusntdaeller dshrealdveias. For Btu per hour ratings at other temperatures, divide table values by factors found in Table 6. b Length equals number of sections times 1} in. 0 Overall height and leg height, as produced by some manufacturers, are one inch (1 in.) greater than shown in Columns A and D. Radiators may be furnished without legs. Where greater than standard leg heights are required this dimension hll be 4} in. " Or equal. RADIATORS Column and large-tube radiators are no longer manufactured, but since many of these units are still in use, Tables 1 and 2 are included to provide principal dimensions and average ratings of them. The small-tube type radiators, with a spacing of If in. per section, are about the only available cast-iron radiating surface for homes and office buildings. Small-tube radiators occupy less space than the older column and large-tube radiators, and are particularly suited for installation in recesses. After a study of the demand for various sizes of radiators, the Institute of Boiler and Radiator Manufacturers, in cooperation with the Division of Simplified Practice, National Bureau of Standards, established Simplified Practice Recommendation R174-47 for small-tube cast-iron radiators. Table 3 shows the size and dimensions now being manufactured. Wall radiators are hung from wall brackets and are well adapted to use Table 4. Cast-Iron Wall Radiators Approximate Dimensions--Inches Heat Output* Height Length or Width Thickness Sq Ft Btu/hr 13)4 13)4 22 2126)4 13)4 13)4 29 6)4 1560 1920 1920 29 13)4 .I| 2640 2640 These ratings are based on steam at 215 F and air at 70 F. They apply only to installed radia- p/3 Posed in a normal manner, not to radiators installed behind enclosures, grilles, or under shelves. r Btu per hour ratings at other temperatures divide table values by factors found in Table 6. 544 ICfDHAATPTlGEiRn w23 1954 Guide in factory buildings. Tests have shown that the heat emitted from a walltype radiator may be reduced from 5 to 10 percent if the radiator is placed near the ceiling with the bars horizontal and in an air temperature ex ceeding 70 F. When radiators are placed near the ceiling, there is usually such a large difference in the temperature between the floor level and the ceiling that it becomes difficult to heat the living zone of the rooms satis factorily. Dimensions and heat emission rates for wall radiators are given in Table[4: Baseboard radiation consists of long, low units which are made to resemble conventional baseboards, and are installed along the outside walls of rooms in;place of the usual wooden baseboard. Units are made either of hollow cast-iron panels (with, or without fins on the back) or of ferrous or nonferrous finned tubing installed behind a metal enclosure. They are pri marily used in hot water systems, but may also be used in two-pipe steam systems. ' There are various kinds of baseboard radiation available,1 the radiant type and the convector type. Radiant baseboards have a substantial portion of the front face water backed, and do not depend upon an enclo- 5.Table Heat Emission op Pipe Coils Placed Vertically on a Wall 215 F(Pipes Horizontal) Containing Steam at and Surrounded 70 Fwith Air at ` Bin per linear fool of coil per hour (not linear feet of pipe) SiiE or Pipe 1 In. 132 252 440 567 651 732 812 li In. 162 312 545 702 796 907 1005 H In. 185 348 793 1020 113l> sure for their heat output. Cast-iron radiant baseboards may be either (1) a full radiant, called Type R, or (2) a radiant convector, called Type RC. The Type RC unit, in addition to the radiant front face, has ex tended convection heating surface on the rear face to increase its output. The convector type of baseboards includes finned tube units with which enclosures are used. The front of the enclosure supplies radiant heat. The basic advantage of the baseboard radiator or of the long low narrow radiator is that its normal placement is along the cold walls and under areas where the greatest heat loss occurs in a room. Other advantages claimed for the baseboard radiator are: it is inconspicuous; it is clean in operation; it offers a minimum of interference with furniture place ment, 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 radiators especially adaptable to basementless homes, where cold floors are prevalent.2 Heat loss calculations for baseboard heating systems are the same as those used for other types of radiation. The procedure for designing baseboard heating systems is given in I = B = R Installation Guide No. 5.1 Ratings for baseboard radiation are expressed in Btu per linear foot. Pipe coils are assemblies of standard pipe or tubing (1 in. to 2 in.) which Radiators and Convectors 545 are used as radiators. In older practice these coils were commonly used in factory buildings, but are not often found in this service today. When coils are used, the miter type assembly is preferable, as it readily permits expansion in tli6 pipe. - The heat emission of pipe coils placed vertically bn a wall, with the pipes horizontal, is given in Table 5, which has been developed from available data and does not represent definite results of tests. For such coils the heat emission varies as the height of the coil. The heat emission of each pipe in ceiling coils, placed horizontally, is about 126 Btu, 156 Btu, and c1o7i5ls.Bt, u per linear foot of pipe, respectively, for 1-in., lj-in., and l-in. CONVECTORS Convectors are space heating devices composed of a casing with outlet grille, and an extended surface heating element of fin-tube or cast-iron fin surface. The casing usually contains a damper. The air enters the en closure near the floor line below the heating element, is heated in passing Fig. 1. Typical Recessed Convector through the element, and delivered to the room through the outlet grille located near the top of the enclosure. The room air movement thus established accomplishes a reduction in floor to ceiling temperature dif ferential, and tends to assure comfort in the living zone. A typical re cessed convector is shown in Fig. 1. Factory-assembled units comprised of a heating element, casing and outlet grille with damper, are widely used. Grilles may be used over the air inlets. " In cases where enclosures are to be used but are not furnished by the heater manufacturer, it is important that the proportions of the cabinet ai>d the grilles be so designed that they will hot impair the performance of the assembled convector. It is desirable that the enclosure or housing for the convector fit as snugly as possible so that the air to be heated cannot by-pass the heating element in passing through the enclosure. Cast-iron heating units may be concealed in a cabinet or enclosure for sppearance. In such cases a greater percentage of heat is conveyed to the room by convection thereby resulting in a form of gravity convector. The output of a convector, for any given length and depth, is a function 546 CHAPTER 23 1954 Guide of the height, of the discharge grille above the heating element. The published ratings are generally given in terms of Btu per hour or square feet of Equivalent Direct Radiation, EDR. For steam convectors, as for radia tors, 240 Btu per hr may be taken as an equivalent square foot of radiation. When more than one heating unit is used, one mounted above the other in the same cabinet, the output of the upper unit or units will be materially less than that of the bottom unit. RADIATOR AND CONVECTOR RATINGS A standard method of testing radiators was adopted by the A.S.H.V.E. in 1927.3 This Code 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 Table 6. Correction Factors for Direct Cast-Iron Radiators and Convectors* Steam'Press. (Approx.) Gage Vacuum Id. Hg. Abs Lb per Sq In. Heating Medium Temp F Steam or Water Factors for Direct Cast-Iron Radiators -- -- __Room Temperature F 80 75 70 65 60 55 50 Factors for Convectors Inlet Air Temperature F 80 75 70 65 60 55 50 22.4 203 17.7 14.6 10.9 6.5 1Lb per Sq In. 6 15 27 52 3.7 46..70 7.5 9.3 11.5 2115.6 30 42 67 200150 160 170 180 190 2.17 2.17 2.00 2.00 1.86 1.73 1.86 1.62 1.73 1.52 1.62 1.44 3.14 2.57 2.83 2.35 2.57 2.35 2.15 1.98 2.15 1.84 1.98 1.71 1.84 1.59 1.86 1.62 1.73 1.62 1.44 1.28 1.52 1.35 1.21 1.44 1.28 1.15 1.35 1.21 1.10 1.28 1.15 1.05 2.15 1.84 1.59 1.98 1.71 1.49 1.84 1.59 1.40 1.71 1.49 1.32 1.59 1.40 1.24 1.17 1.11 1.28 1.21 1.15 1.10 1.05 1.00 0.96 1.40 1.32 1.24 1.17 1.11 1.05 $00215 230 250 270 0.81 1.00 0.96 0.92 0.88 0.85 0.76 0.73 0.68 0.66 0.64 0.92 0.81 0.7C 0.62 0.88 Q.7S 0.61 0.6( 0.85 11.17 0.76 |1.0C 0.66 10.KJ 0.51 p.7{ 1.11 1.05 0.95 0.91 0.7V 0.76 0.61 0.65 1.00 0.95 0.91 0.87 0.87 0.83 0.79 0.76 0-73 0.70 0.65 0.63 0.60 u.o8 0.58 0.57 0.55 0.53 0.52 0.51 0.48 p.56 0.54 0.53 0.51 0.40 a To determine the sue of a radiator or a convector for a given space, multiply the beat loss oi toe space in Btu per hour by the proper factor from the above table and select radiator or convector having an equiva lenAt nBtaulteprenratheomuretrhaotidngis. to divide the heat loss in Btu per hour by 240 and multiply the result by the proper factor from the above table and select radiator or convector having an equivalent square foot rating. To determine the heating capacity of a radiator or a convector under conditions other than the basic ones with the heating medium at a temperature of 215 F, and the room temperature at 70 F in the case of a. radiator, and the inlet air temperature at 6$ F in the case of s con vector, divide the heating capacity at the basic ratiQg conditions by the proper factor from the above table. an elevation of 5 ft above the floor. The steam temperature in the radi ator is to be 215 F, which corresponds to 15.6 lb per sq in. absolute. The weight of condensate per hour, under these standard conditions, multi: plied by the difference in the enthalpy of the steam entering the radiator and that of the condensate leaving the radiator, gives the radiator output in Btu per hour. This output divided by 240 gives the steam rating of the radiator in equivalent square feet, EDR.' Similar test methods for convectors are the A.S.H.V.E. Codes for Testing and Rating Concealed Gravity Type Radiation,* (Steam Code 1932 and Hot Water Code 1933). These Codes recognize a different type of test booth, and the air temperature used is that of the air entering the convector casing instead of the temperature in the center of the room. The entering air temperature for standard test conditions is 65 F. For hot water the standard test conditions call for a mean temperature of the water in the convector of 170 F. The method of testing and rating both ferrous and non-ferrous convec tors, which is now generally accepted, is given in Commercial Standard CS140-47, Testing and Rating Convectors, which has been developed co Radiators and Convectors 547 operatively by the Convector Manufacturers Association, the Institute of Boiler and Radiator Manufacturers, other members of the trade, and the National Bureau of Standards. The rating of a top outlet convector is established at a value not in excess of the condensation capacity (which is the heat extracted from the steam or water in the convector, under standard test conditions). The rating of a front outlet convector includes the condensation capacity plus an allowance for heating effect in the occupied zone, based on convector enclosure height from bottom of the enclosure to top of the outlet. A table of heights and heating effect allowances is given in the Commercial Standard CS140--47, and lists allowances from zero percent for a 38-in. height to 15 percent for a 20-in. height, or less. For an inclined outlet convector the rating includes the condensation capacity, plus a heating effect allowance obtained by multiplying the allow ance for a front outlet convector by a factor (angle of outlet to horizontal H-90). Approval of convector ratings may be obtained by the manufacturer by submitting test data to a Convector Rating Committee appointed by the Division of Trade Standards of the National Bureau of Standards. Re quests should beaddressed to the Division of Trade Standards. . A Testing and Rating Code for Baseboard Type of Radiation6 was adopted by the Institute of Boiler and Radiator Manufacturers in 1950. This code contains test procedures for determining steam ratings which are obtained from the condensation capacity (converted to standard conditions) by adding a maximum of 15 percent. The ratings are expressed in Btu per hour per linear foot, and may also be expressed in square feet of steam radiation per linear foot. Water ratings are determined by applying the factors shown in Table 7 to the steam ratings, and are expressed in Btu per hour per linear foot for each average water temperature listed. A method for testing baseboard radiation with water for the purpose of determining water ratings is being considered. Manufacturers who. wish to publish baseboard radiation ratings as I = B -- R ratings may submit test data to the I = B = R Baseboard Rating Committee and receive approval of test procedure and ratings. The fol lowing catalog information must be given for 7 = B = R Steam Ratings: (1) rating in Btu per hour per linear foot, (2) percentage added to capacity in determining ratings, and (3) name and other type of designation. The following information must be given for 7 = B = R Water Ratings: (1) rating in Btu per hour per linear foot for each average water tempera ture listed, (2) percentage added to capacity in determining ratings, (3) name or other type of designation, and (4) a statement that the water ratings have been determined by applying to the I -- B = R Steam Ratings the factors (see Table 7) approved by the Institute of Boiler and Radiator Manufaclurers. Effect of Operating Conditions The heat output of a radiator is proportional to the 1.3 power of the temperature difference between the air in the room at the 60 in. level and the heating medium in the radiator. The heat output of a convector is Proportional to the 1.5 power of the temperature difference between the air entering the convector and the heating medium, steam or hot water, Within the convector.6 For hot water the arithmetical average between 548 CHAPTER 23 1954 Guide Table 7. I = B = RFactors to Convert Steam Ratings to Hot Water Ratings at Temperatures Indicated / Radiator Temperature. Factor Radiator Temperature Factor . Radiator Temperature Factor 150 0.45 . 175 165 0.49 180 160 0.53 185 . 165 .0.57 190 170 * 0.61 195 0.65 . 200 0.69 205 0.73 210 0.78 215 0.82 220 0.86 0.91 0.95 1.00 1.05 entering and leaving water temperatures is used. These laws may be ex pressed as correction factors to change from output under standard ratingtest conditions, to output under other operating conditions. Such factors are given in Table 6. When it is desired to change the output under any test conditions to the corresponding output under standard code test conditions, the recip rocal form of correction factor may be derived. The equations for steam units are: . For radiators For convectors f0' (2) The output under standard conditions will be: H. = CJh where C, = correction factor, t, = steam temperature during test, Fahrenheit degrees. t, -- room temperature during test, Fahrenheit degrees. t. = iniet air temperature during test, Fahrenheit degrees. H. = heat emission rating under standard conditions, Btu per hour. Ht = heat output under test conditions, Btu per hour. (3) The relation between the size of the radiator or. convector and the size of the test room will, affect the results obtained in a capacity-rating test.7 The height and location of the radiator and the insulation of the test room are other important factors that are not specifically regulated by the codes. For a radiator, 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 reduction of 10 percent or more in the total heat output of the radiator.8 -10 Radiator enclosures and convector cabinets of proper design may im prove the heat distribution within the room as compared to the heat dis tribution obtained with an unenclosed radiator.11 Heating Effect For several years the term heating effect has been used to designate the. relation between the useful output of a radiator, in the comfort zone of a room, and the total input as measured by steam condensation or water Radiators and Convectors 549. temperatures.12'13 The application of such a heating effect factor implies that some radiators and convectors use less steam than others for pro ducing equal comfort heating results in the room. All authorities do not agree that the use of heating effect factors are justified. No standard method for evaluating the heating effect of radia tors and convectors and correlating it with comfort has yet been accepted. One method, with test data14 on radiators and convectors, and making use of the eupatheoscope for evaluating the environment produced, has been sug gested by the University of Illinois. The principle underlying the eupa theoscope involves the measurement of the heat loss from a sizable body by radiation and convection, when the surface is maintained at some constant temperature. Through the use of this instrument and its calibration curve, non-uniform environments may be referred to uniform environments 1 3 * " 5 " 6 .7 Hfinm ABOVE FLOOR IN FEET Fig. 2. Temperature Gradients and Equivalent Temperatures for .Kadiator and Convectors with Common 30 in. Level Temperature in which the air and all surrounding surfaces are at the same temperature. The temperatures of the uniform environments are referred to as equivalent temperatures. The Kata thermometer,15 the thermo-integrator,16-17 and the globe 18 thermometer are other instruments which have been used to measure the influence of air temperature, air movement and radiation in an environment; . Data given in Fig. 2 stiow that while the air temperature at the '30-in. level is the. same for the three convectors and the one large-tube cast-iron radiator, in position No. 3 in the test room, the equivalent temperature is 1.5 deg lower than the air temperature in the case of the three convectors, and the same as the air temperature in the case of the radiator. The difference between the minimum and the maximum amount of heat: re quired to maintain the common air temperature at the 30-in. level is of the order of 13 percent. In Fig. 3 are shown the results of tests made with the same three convec tors and the one large-tube cast-iron radiator, so adjusted in size that each gave approximately the same equivalent temperature in the No. 3 position ni the test room. The difference between the minimum and the maximum 550 CHAPTER 23 1954 Guide amount of heat required to maintain the common equivalent temperature is of the order of 7 percent. / Figs. .2 and 3 show results obtained in cold room tests in which the radiators were continuously filled with steam at 215 F. Under these conditions of operation, air temperature gradients are likely to be exag gerated as compared with those encountered with the intermittent opera tion usually obtained in actual practice. The following statements applying to the use of radiators are based on experience and test results:13 1. The heating effect of a radiator cannot be judged solely by the amount of steam condensed within the radiator. HnTil ITT d rwxn temp m tf 1 I 11111 lj 5,91 lb convector Ma 1 T vvrlr 647 tb convector No. 22 111LL 44, &20 lb convector No. 6 m |sl32 lbjftuberwJietor Temperature tn deg F Position No. 3 Position No. 1 Eourv DiH 30-level Equfv 69.4 69.9 68.7 67.9 678 16 A 7 *1.7 67.6 *1.1 67.9 OD 68.2 664 *1.8 Convector No. 22 Convector No. I non-ferrous iron heating unit hMWgunrt ,1-sj____ _ 4' rt- ^tube cast iron radiator Convector No. 6 non-ferrous beating unit "1-------- 2 F 4 5 6" 7 height above floor in feet Fig. 3. Temperature Gradients and Equivalent Temperatures for Radiator and Convectors with Common Equivalent Temperature 2. Smaller floor-to-ceiling temperature differentials can be maintained with long, low, thin, direct radiators, than can be maintained with high, direct radiators. 3. The larger portion of the floor-to-ceiling temperature differential in a room of average ceiling height heated with direct radiators occurs between the floor and the bre4a.thTihneg cleovmelf.ort level (approximately 2 ft-6 in. above floor) is below the breathing line level (approximately 5 ft-0 in. above floor), and temperatures taken at the breath ing line may not be indicative of the actual heating effect of a radiator in the room. The comfort-indicating temperature should be taken below the breathing line level. 5. High column radiators placed at the sides of window openings do not produce as comfortable heating effects as long, low, direct radiators placed beneath windows. HEATING THE RADIATOR AND CONVECTOR ` The maximum condensation occurs in a heating unit when the steam is first turned on. Tests1' on an old-style column-type cast-iron radiator indicated that in the first 10 min the condensation rate reached a peak of 0.95 lb per sq ft of radiation per hour and 10 to 15 min later dropped to a . rate of 0.24 lb. In one-pipe gravity systems the rate of steam supply to the heating unit, while heating up, is frequently retarded by controlled elimination of air through air valves or traps. In two-pipe systems auto matic control valves may also retard the supply of steam. Vacuum types Radiators and Convectors 551 of air venting valves may be used to reduce the length of the venting periods. , ENCLOSED RADIATORS The general effect of an enclosure placed about a direct radiator is to restrict the air flow, diminish the radiation and, when properly designed, improve the heat distribution within the heated space. .: Investigations13 indicate that in the design of the enclosure three things should be considered: 1. j. uere snouici De Detter distribution of the heat below the breathing line level to produce greater heating comfort and lowered ceiling temperatures. 2. The lessened steam consumption may not materially change the radiator heat ing performance. 3. The enclosed radiator may inadequately heat the space. A comparison between a bare or exposed radiator (A) and the same radi- (C), aVn.1d0Hwithwaenc-luoetthsicgonevaere(nDc)lowsuilrleill(uBs)t,rawteiththea rpeolaotrilvye-dheesaigtninegdcehnacrlaocstuerre istics. In Fig. 4 the curve (B) reveals that the enclosed radiator used less steam than the exposed radiator, but gave a satisfactory heating perform ance. A well-designed shield placed over a radiator gives about the same result. Curve (C) shows the unsatisfactory effects produced by improperlydesigned enclosures. Curve (D) shows that the effect of a cloth cover extending downward 6 in. from the top of the radiator was to make the Performance unsatisfactory and inadequate. Some commercial enclosures and shields for use on direct radiators are Quipped with water pans for the purpose of adding moisture to the air m the room. Tests20 show that an average evaporative rate of about 0-235 lb per square foot of water surface per hour 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 aero ds.3- 552 CHAPTER 23 1954 Guide . REFFERENCES 1 I=B=R Installation Guide No. 5, Baseboard Heating Systems .(Institute of Boiler and Radiator Manufacturers, Second Edition, T953V 3 A Study of Radiant Baseboard Heating in the I = B=R Research Home, by Alonzo P. Kratz and Warren S. Harris (University of Illinois, Engineering Experi ment Station Bulletin No. 358, 1945). ' 3 A.S.H.V.E. Code for Testing Radiators (A.S.H.V.E. Transactions, Vol. 33, 1927, p. 18). . 4 A.S.H.V.E. Standard Code for Testing and Rating Concealed Gravity Type Radiation (Steam), (A.S.H.V.E. Transactions, Vol. 37, 1931, p. 367); (Hot Water), (A.S.H.V.E. Vol.Transactions,! 39, 1933, p. 237). (See also A.S.H.V.E. Trans actions, Vol. 41, 1935, p. 38; and Vol. 42, 1936, p. 29). 4 I=B=R Testing and Rating Code for Baseboard Type of Radiation (Institute of Boiler and Radiator Manufacturers, First Edition, July 1950). * A.S.H.V.E. Research Report No. 998--Factors Affecting the Heat Output of Convectors, by A. P. Kratz, M. K. Fahnestock, and E. L. Broderck (A.S.H.V.E. Transactions, Vol. 40, 1934, p. 443). . 7 Factors Influencing the Heat Output of Radiators, by A. C. Davis, W. M. Sawdon and David Dropkin (A.S.H.V.E. Transactions, Vol. 42, 1942, p. 185) and (Cor nell University, Engineering Experiment Station Bulletin Ho. 29, April, 1942). * Heat Emission from Radiators, by K. F. Rubert (Cornell University, Engineering Experiment Station Bulletin No. 24, 1937). 8 Comparative Tests of Radiator Finishes, by W. H. Sevems (A.S.H.V.E. Trans actions, Vol. 33, 1927, p. 41). : . 10 Heat Loss from Direct Radiation, by j. R. Allen (A.S.H.V.E. Transactions, Vol. 26, 1920, p. 11). 11 Heat Output of Concealed Radiators, by E. A. Allcut (University of Toronto, School of Engineering Research Bulletin No. 140, 1933). 18 The Heating Effect of Radiators, by Charles Brabble (A.S.H.V.E. Transac tions, Vol. 33, 1927, p. 33). 13 Investigation of Heating Rooms.with Direct Steam Radiators Equipped with Enclosures and Shields, by A. C. Willard, A. P. Kratz, M. K. Fahnestock and S. Konzo (A.S.H.V.E. Transactions, Vol. 35, 1929, p. 77 or University of Illinois, Engineering Experiment Station Bulletin No. 192). Investigation of Various Factors Affecting the Heating of Rooms with Direct Steam Radiators, by A. C. Willard, A. P. Kratz, M. K. Fahnestock and S. Konzo (University of Illinois, Engineering Experi ment Station Bulletin No, 223). : 14 A.S.H.V.E. Research Report No. 962--The Application of the Eupatheoscope for Measuring the Performance of Direct Radiators and Convectors in Terms of Equivalent Temperature, by A. C. Willard, A. P. Kratz and M. K. Fahnestock (A.S.H.V.E. Transactions,' Vol. 39, 1933, p. 303). 13 The Kata Thermometer--Its Value and Defects, by W. J. McConnell and C. P. Yagloglou. (Reprint No. 953 from U. S. Public Health Service Report, pp. 2293-2337, September 5, 1924). 13 The Thermo-Integrator--A New Instrument for the Observation of Thermal Interchanges, by C.-E. A. Winslow and Leonard Greenburg (A.S.H.V.E. Transac tions,.Vol. 41, 1935, p. 149). 17 The Calibration of the Thermo-Integrator, by C.-E. A. Winslow, A. P. Gagge; Leonard Greenburg, I. M. Moriyama and E. J. Rodee (The American Journal of Hy giene, Nol. 22, No. 1, July, 1935, pp. 137-156). - 13 The Globe Thermometer in-Studies of Heating and Ventilation, by T. Bedford and C. G. Warner (The Journal'of Hygiene, Vol. 34, No. 4). , 13 A.S.H.V.E. Research Report No. 1067--The Cooling and Heating Rates of a Room with Different Types of Steam Radiators and Convectors, by A. P. Kratz;"M. K. Fahnestock and E. L. Broderick (A.S.H.V.E. Transactions, Vol. 43, 1937, p 389). 38 Humidification for Residences, by A. P. Kratz (University of Illinois, Engineer ing Experiment Station Bulletin, No. 230, p. 20). vAn Tak rtViWH.iVcA 1A4A PANEL HEATING Definitions; Application Methods: Embedded Piping for Ceilings, Walls, or Floors; Warm Air and Electrically Heated Ceilings, Walls, or Floors; Output from Panel Surfaces: Radiation, Convection and Combined Heat Transfer; Floor Panel Design: Design Conditions, Calculation of Room Heat Loss, De termination of UMRT, Determination of Panel Output, Graphical Determination of Panel Input and Water Temperature; Ceiling and Wall Panel Design; Hot Water Piping, Installation and Control; Snow Melting: Design and Installation IN this chapter the term, Panel Heating, is used to describe a method of space heating which employs 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 surfaces. Panel heating may be considered as another method of convenient and effective space heating. The heat loss requirements may be calculated in the conventional manner except that the heat loss through the area occu pied by the heated panel need not be included. An assumed reverse heat loss from the panel, however, should be included in determining 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 main tained 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 similar topics that apply to all methods of heating interior spaces for human -comfort. The reader is referred to Chapter 6 for a detailed discussion of these subjects. APPLICATION METHODS The great majority of panel installations of the past 40 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 pip ing. More recently, the use of warm air ducts, and embedded electrical heating elements, has come into favor, especially where specific local fac tors 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 ai i, 1 and | in. O.D., while piping* is generally for 1 in. I.P.S. Where ooils are embedded in concrete or plaster, no threaded joints should be used mr ferrous pipe coils. The construction should be; of all-welded type. Changes in direction should be made by bending the pipe itself, rather than by use of fittings. Solder-joint fittings are used for non-ferrous heating 553 554 CHAPTER 24 1954 Guide coils and piping. It is recommended that a medium temperature solder of 95 percent tin--5 percent antimony, or capillary brazing alloys, be used. All piping is, generally, subjected to. a hydrostatic test of at least three times the working pressure, but not less than 150 psig. The more common forms of application of panel heating fall into the following general categories: (1) embedded piping for ceilings; (2) em bedded 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 concrete slab, generally very cloBe to its lower surface. If plaster is to be applied to the concrete, the piping A''-ScOMCftCTt slaA- 'o o * S3? t a 1& HEATMG cotws . V Fig. 1. Coils in Structural Concrete Slab C**TCM COA1 Fig. 3. Coils in Plaster Below Lath Plaster Ceiling Below Joists Fig. 2. Coils in Plaster Above Lath may be placed directly on the wood forms. If the slab is to be used without plaster' finish, then the piping is installed about J in. above the undersurface of the slab. Fig. 1 shews this method of construction. It is important that any local construc tion codes which may affect the position of the piping be consulted. ' b. Pipe or tubing 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 supporting members in such a way that the lath is below, but in good contact with the ceils, 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 tubes of the smaller diameters are 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 utilize prefabricated panels of metal, composition board, wood paneling, etc., having warm water piping, tube or channels built into the panel sections. Coils are usually of the sinuous type, although some header or grid type coils have been used in ceilings. Coils may be of either ferrous or non-fer-. Panel Heating 555 rous pipe or tube, with coil pipes spaced from 4| .to 9 in.: on centers, de pending on the required 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 | in. of cover be low the tubes when the tubes are installed below the lath. Generally, the surface temperature 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 temperature 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. 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 (b) the floor is above grade. iti.vuo aim uuu-iciTuud pipe ana wine are.used m floor slabs which rest oo grade. The coils are constructed as either sinuous-continuous pipe coils, or ar ranged as header coils with the pipes spaced from 6 to 18 in. on centers. The coils are generally installed with 1 to 4 in. of cover above 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 embedded com pletely and should not rest on an interface. Generally, a waterproofing layer is desirable to protect insulation and piping. b. Where the coils are embedded in structural load supporting slabs above grade, construction codes may affect their position. Otherwise, the coil piping is installed ln the same manner as described for slabs resting on grade. Fig. 5. Warm Air Plaster Ceiling Construction 556 OUT$IOt wall CHAPTER 24 ASPHALT tHPOe&H*Tt& INSULATION BOARD POURED SI.AS , PRECAST SLAB rnmCRFTC PL.OOA SUPPORT* AND DIRECTIONAL VANES AIR' PLENUM CONCRETE INSULATION -. .. CAAVCL OR ROCK TILL 4954 Guide Fig. 6. Warm Air Floor Panel Construction Air Heated Ceilings, Walls, and Floors Several methods have been devised to warm the interior room surfaces by circulating heated air through passages behind these surfaces. In some cases, the heated air is recirculated in a closed system. , In others, all or a part of the air is passed through the. room on its way back to the furnace to provide supplementary heating and ventilation.1 Figs. 5 and 6 indicate two common types of construction. Care must be exercised to assure com pliance with any building codes that might apply. (See also section on Warm Air Ceiling Panels in Chapter 20.) Electrically Heated Ceilings, 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 manner similar to hot water piping inconcrete or plaster; (2) prefabricated electric heating panels to be attached to room surfaces; and (3) electrically heated fabrics or other materials for applica tion to, or incorporation into, finished room surfaces. Figs. 7 and 8 indi cate two methods of installation. The constructions of electric panels for ceilings, walls, and floors are described in greater detail in Chapter 42, Electric Heating. ; OUTPUT FROM PANEL SURFACES The heat transfer from a panel is accomplished by radiation and con vection, which are considered in following paragraphs. . Radiation Transfer The radiation transfer can be evaluated by means of the relationship set up by Stefan and Boltzmann: S^TIUNDSSUPLAACTEION 1ELa-RIOtO LATH H^meatinO CABLCS (STAPLCO TO LATh) TINiShCD PLASTER Fig. 7. Electric Heating Cables in Plaster Fig. 8. Prefabricated Electric Panel Panel Heating . 557 where :. .. q, = heat transfer by radiation, Btu per (square foot) (hour). . T, = absolute,temperature of panel heated surface, Fahrenheit. 7'w = absolute; mean radiant temperature of all unheated surfaces, Fahrenheit.- F = the configuration factor (dimensionless). F, == the emissivity factor (dimensionless). ., For. larg;e parallel planes or large enclosed surfaces as ordinarily en countered in panel heating practice: ' where and e, = emissivities of the respective surfaces. In heating practice et and e2 are usually equal to 0.9 and Fe to 0.82. Also, the configuration factor Fa is equal to 1 for large parallel planes, long concentric cylinders, or smaller bodies in large enclosures. There fore, for ordinary rooms with parallel walls, regular floors and ceilings, with an emissivity factor of 0.82, Equation 1 can be simplified to: ' -|(.y (,yj Irregularities in room surfaces and materials may introduce some error the application of this radiation relationship. However, most author ities are in agreement that the heat emission by radiation, as calculated m this manner, can be considered accurate within 10 percent. Radiation 558 CHAPTER 24 1954 Guide values are shown in Fig/9 for various surface temperatures. These values are applicable for either floor, wall, or ceiling panel radiation outputs. Convection Transfer Convection values of heat transfer are not easily established. Con vection in a panel heated space is usually considered to be of the natural type; that is, air motion is generated by the wanning (by conduction) of the boundary layer of air which starts moving as soon as its tempera ture exceeds that of the surrounding air. In practice, however, there are many factors interfering with natural convection. Infiltration, localized drafts, ventilation, and movement of persons are all likely to disturb this process so that it becomes difficult to determine the exact convection effect. Until results from current research become available, an interim evaluation of convection heat exchange can be determined for ordinary panel heating applications from available theoretical relationships. As investigated3' * 3 by Nusselt and Henky, Griffiths and Davis, Wilkes . and Peterson, McAdams and others, natural convection is found to be affected by only two factors: (a) temperature difference between the heat emitting surface and the surrounding air and (b) the position of the sur face. ' . The basic general equation for natural convection from a flat surface is of the following form: 9 = /e(f. -- (.)" (4) where . . .: 9c = heat transfer by convection, Btu per (square foot) (hour). /,, = a coefficient (surface conductance) representing the heat transfer from a unit area per unit difference in temperature, Btu per (square foot) (hour) (Fahrenheit degree temperature difference between surface and air), n = an exponent depending on surface position and temperature difference be tween the surface and the surrounding air. t, = temperature of the surface, F. : L -- temperature of the air, F. The value of n is usually taken as 1.25 regardless of the magnitude of the temperature difference and the position of the surface. However, Wilkes and Peterson state that a value of 1.12 for n is more appropriate for low temperature differences, with heat flow upward from horizontal surfaces, and that a value of 1.00 is best in the case of heat flow downward from horizontal surfaces. The various investigators mentioned also indi cate that values of /c vary from 0.2 to 0.38 for downward heat flow from ceilings, and from 0.38 to 0.81 for upward heat flow from floors. The variation in the value of as reported by the various investigators, is dependent upon the temperature difference and the value of the exponent n. More recent experimental work indicates a provisional correlation be tween measured convection outputs in actual floor panel heated rooms, and the laboratory values obtained by the previous investigators. This correlation indicates that the values obtained from Wilkes and Peterson's equation 1 q, = 0.81 (t. - !.)'> (5) for heat flow upward from horizontal surfaces and small temperature differences, give results that check within reasonable precision the eon- Panel Heating 559 vection output from floor panels, with temperature differences as recom mended. Curve A in Fig. 10 is based on the equation of Wilkes and Peterson, and gives values which may be used for convection outputs from floor panels. More experimental data are required on convection outputs of ceding panels. The warming of the air by "a ceiling panel does not in itself create convection currents. Instead, it is the action of cooling along the outside wall or walls which causes the air movement. In lieu of actual test data which would take this factor into account, it is recommended that, the values toiobtnained from Curve B in Fig. 10, based on the Nusselt and Henky equa *9c = 0.22 (<. - (J` " . .(gj JJ, . -- msiuw air temperature > IG. 10. Heat Output bt Convection fbom Floob and Ceiling Panels. be used for determining convection outputs from ceiling panels for various surface temperatures. Combined Heat Transfer The sum of the radiant heat transfer from Fig. 9 and the convective transfer from curve A or B of Fig. 10, gives the combined useful heat trans fer to the room for any combination of panel surface temperature, room air temperature, unheated mean radiant temperature (UMRT), and . panel location. Example 1: Find the combined total useful heat transfer from a square foot of ooor panel having a surface temperature of 85 F, when the average room air tempera ture is 70 F and the mean radiant temperature UMRT of the unheated room sur faces is 60 F. Solution: Radiation . Btu/(hr)(sq ft) (Fig. 9 for UMRT of 60 F and t. of 85 F) Convection 21.4 (Fig. 10, Curve A for a temperature difference of 15 deg F) 16.9 Total useful heat transfer 38.3 560 CHAPTER 24 1954 Guide Example : Find the combined total useful heat transfer from a square foot of ceiling panel haying a surface temperature of 100 F, when the average room air tem perature is 70 F and the mean radiant temperature UMRT of the unneated room sur taxes is 60 F. ' Solution: Radiation . (Fig. 9 for UMRT of .60.F and t. of 100 F) Btii/0>rKsq tt) 35.3 . Convection (Fig.' 10, Curve B for a At of 30 F) 15.5. Total useful heat transfer 50.8 Since the greater number of panel installations are designed for an a verage room air temperature of 70 F, it is possible to present in chart form (nee Fig. 11) the relationship between panel output (radiation plus con- vsetion) and.the unheated mean radiant temperature for various surface t/anperatures and panel positions based on 70 F inside air temperature. Panel Heating 561 Fig. 12 must be corrected by values obtained from Fig. 13. The follow ing example illustrates the use of Figs. 12 and 13. Example S: The outside walls of a room' have a coefficient of heat transfer U = 0.15. Inside and outside design air conditions are 68 F and -- 20 F, respec tively. Determine the inside surface temperature of the wall. Solution: From Fig. 12 the inside surface temperature for 70 F and --20 F, and a V value of 0.15 is found to be 61.5 F. Then from Fig. 13, for a At = --2 deg and a U value of 0.15, the correction is --1.8 deg. As the correction is negative, the inside surface temperature will then be 61.5 -- 1.8 = 59.7 F. The total panel output can then be determined from Figs. 9, 10, and 11. After the various wall surface temperatures have been determined, as described, the unheated mean radiant temperature UMRT of the space Output based on 70 F inside air temperature . Fig. 11. Total Panel Output Radiation Plus Convection From Fig. 11 the panel output for Examples 1 and 2 can be read directly, 38.3 and 50.8 Btu, respectively. Similarly, combined transfer rates for floor or ceiling panels operating under other conditions may be determined from Fig. 11, or from Figs. 9 and 10. Before Figs. 9 and 11 can be used; the unheated mean radiant tempera ture UMRT of the room surface must be known. For the purpose, of this work, the UMRT may be defined as the average temperature of the unheated surfaces of the space, weighted according to the areas of the surfaces. The surface temperature of the inside walls may be assumed to be the same as the inside air temperature. The surface temperatures of outside walls or exposed ceilings, for any combination of outside design tempera ture and transmission coefficient, may be obtained from Fig. 12. .-If the inside design temperature is other than 70 F, the values determined from Inside air temperature "70 F . Fig. 12. Relation or Oveball Coefficient of Heat Tbansfeb to Inside Subface Tempebatube may be calculated as illustrated in Step 3 of the following section on Floor Panel Design Illustration. FLOOR PANEL DESIGN ILLUSTRATION . The several steps in the design of a panel heating system are listed and illustrated in the following example of the design of a floor panel for the room shown in Fig. 14, 1. Selection of Design Conditions Outside design temperature, --10 F. b. Inside design room air temperature, 70 F. c- In this problem a floor panel heating system will be used. Insulation will be used between slab and fill, d- Heating medium, hot water, e. Floor surface temperature, 85 F (Maximum). No basement. 562 CHAPTER 24 1954 Guide Fig. 13. Inside Wall Subface Temperature Correction for Inside Air Temperatures Other Than 70 F . A = If Ai is -- 70 positive: t-w' = fw + correction ta = inside air temperature ' fw = inside wall surface temperature based on = 70 P If AJ is negative.' tw' (#- correction <'. = actual inside wall surface temperature 2. Calculation of Room Heat Loss . The heat transmission coefficients of the room surfaces are given in Fig. 14. They would usually be obtained from Chapter 9. The room heat loss can be calculated in the conventional manner, as outlined in Chapter 12. The calculations are shown in Table 1. The heat loss through the surface areas containing the heating medium is notTihneclcuadlecduliantetdheractealocuf lhaetiaotnl.oss will determine the amount of heat which must be supplied by the heating panels to the room. WEST Fig. 14. Room Plan for Illustration of Method of Designing a Panel Heating System Data: Values of overall heat transfer coefficients as calculated: 1. Outside walls U = 0.10 3. Floor U = 0.36 2. Ceiling U = 0.08 4. Windows V - 0A5 Panel Heating 563 Table 1. Calculated Heat Loss of.Room (Fig. 14)' Surfaces Outside walls... Inside walls. . .. Ceiling............ Floor............. Infiltration... . Aua Sq Ft 272 80 352 480 480 Total heat loss . . a 0.10: T 3. Determination of UMRT ' Calculation HBearot/nLroass' 272 X 0.10 x 80 80 x 0.55 x 80 No heat loss 480 x 0.08 x 80 Heating panel 3,840 cu ft x 1.50 x 80 x 0.018 ' 2,176 ' 3,520 : 0i 3,072 0 8,295 17,063 ' t face ------------- - 7 temperatures shown in the <juxn.i are fourth column wsneorewndeinteTrmaibnleed2fro` TmheRiMgnniai1riu2fin gut* Table 2. Calculation of UMRT Surface Outside walls Adjacent inside wails . Ceiling. .. . C---la--s--s---.-.------- Total.................. Area Sq Ft Inside Surface* Temperature F Product - (Area x Tkmpkraturx) 0.10 0.08 t 0.55 272 352 480 80 1,184 65 17.680 70 24,640 66 31.680 43 3,440 j //,440 UMRT = Total of products _ 77,440 Total area = 65.4 F 1,184 * Values of inside wall aurf&oe temperature for various U values and outside design Fig. 12. T. temperatures foun.d in 4. Determination of Panel Output Values of total panel output for various panel positions, panel surface tempera tures and unheated MRT are given in Fig.'ll. From Fig. 11, with a floor panel sur face temperature of 85'F and a UMRT of 65.4 F, the total panel output is 34 Btu per (hr) (sq ft of panel surface). . Panel area = 24 x 20 = 480 sq ft . Panel output = 480 x 34 = 16,320 Btu per hr This panel output of 16,320 Btu per hr is reasonably close to the calculated room loss of 17,063, ana is satisfactory. If this value of total heat output from panel to the room were much less, *.e., 10 or more percent less, thaD the calculated neat loss from the room, some method of supplementary heating would be needed: Floor panel surface temperatures exceeding 85 F are not recommended. 5. Determination of Panel Input and Water Temperature Fig. 15 presents a graphical method of determining the required water tempera ture and total heat input to a pane) for various cover depths, tube or pipe sizes and spacings, and rate of neat output to the room. The panel output for this example has previously been found to be 34 Btu per (hr) (sq ft). Since some of the heat input to the panel is lost to the ground, it is necessary to supply more than 34 Btu per (hr) (sq ft) to the panel by means of the hot water heating medium. The amount of heat which must be supplied to the Panel to give the required output may be determined graphically from Fig. 15. Asflume that the panel has } in. pipes, spaced on 12 in. centers, and that the depth of cver from top of panel surface to top of pipes is 2.5 in. The four sections of Fig. --sM 564 CHAPTER 24 1954 Guide 15 are marked Part 1 to Part 4 and, as will be evident by following the dashed line on Pthaericth.artS, taarertiunsgedfraosmfotlhloewdse: pth of cover (2.5 in.), proceed vertically to the line representing pipe spacing on centers (12 in.), and then horizontally to the first ordi natPeaorft P2.arMt 2o.ve parallel to the nearest upward sloping line, indicating "2 in. & over" cover, to intersect the ordinate representing 5 in. pipe, and then proceed hori zonPtaarlltySt.oPthroecefiersdt poardrainllaetletoof Panadrta3l.ong the nearest downward sloping line to an intersection with the ordinate representing the panel output (34 Btu per sq ft), and then move horizontally to the right hand scale of Part 3 and read a required average waPtearrtte4m peFrraotmurethine twheatceorilteomf p10e6raFt.ure 106 F just found in Part 3, proceed hori zontally into Part 4 to intersect the line representing insulation between the slab and fill. Directly below this intersection read 1.09 (on the bottom scale) as the muTlthipelireerqtuoirebed upsaende.l. input is, therefore, 1.09 x panel output, or 1.09 x 34 = 37.1 Btu per (sq ft) (hr). . " The total required panel input is 37.1 x panel area = 37.1 x 480 = 17800 Btuh. . CEILING AND WALL PANEL DESIGN Where coils are embedded in plaster on ceilings or walls, design pro cedure is simplified considerably by the physical limitations of the space available. For tube fastened to the underside of lath, the largest practical size is | in. O.D., while for ferrous pipes above the lath, it is 1 in. I.P-STherefore, the actual tube or pipe size selected is usually determined by the length of coil circuit and its flow resistance in consideration of the . avaInilaobrldeecrirtcouloabtitnaginhaearde.asonably even heat distribution over the finished Panel Heating 565 plaster heating surface, pipes or tubes should be spaced on about 6 in. centers, and not over 9 in. centers. Within these limitations it ia found in practice that heat output rates do not vary too seriously with variations in pipe and tube size and tube spacing. In general, for plaster ceiling panels with tubes or pipes spaced on 4^ to 9 in. centers, the temperature of the circulating water is about 10 te25 deg above the desired surface temperature. The hourly heat output per square foot of panel surface may be found by means of Figs. 11, 12, and 13, and the calculations for room heat loss and UMRT, as previously illustrated in the example of floor panel design. HOT WATER PIPING When water is used as the heating medium, the piping layout and ar rangement should be based on the design principles outlined in Chapter 22 for Two-Pipe Forced Circulation Systems. The pressure drops through the coils should be carefully calculated, and it is recommended that all branch circuits and coils be balanced to provide for uniform distribution by means of regulating valves or tees. Generally, a 15 to 20 deg total temperature drop is used in determining water flow rates, and a total'pump head of more than 30 ft is undesirable due to noise caused by high water velocity. . Panel systems involving several rooms and panels comprising a single zone, require that all coils be selected for the same inlet water tempera tures. Panel areas and pipe spacing must be selected to make this pos sible. INSTALLATION DETAILS, ACCESSORIES, AND CONTROLS Installation details, as given in Chapter 22, Hot Water Systems, also apply to piping systems for panel heating. Control problems of panel heating systems are discussed in Chapter 39, Automatic Control. . Efficient venting of air from the coils may be obtained by arranging the circulation so that the air moves in the direction of water flow to a high point in the system where an automatic float-type vent or connection to expansion tank should be provided for its release. Coils should be installed as nearly level as possible or, if they are on sloping surfaces due to structural conditions, they should be arranged to vent air at their high points. Arrangements of pumps, expansion tanks, drainage, and flow and return mains may be generally the same as for conventional hot water heating systems. SNOW MELTING The practicability of melting snow by means of heated coils has been demonstrated in a large number of installations in sidewalks, roadways, ramps, and runways. In addition to eliminating the heed for snow removal, other advantages gained are greater safety to pedestrians and vehicles, and reduction of labor in removal of slush from floors. . The design of a snow-melting system involves primarily (1) a determina tion of the heat requirement which depends on snow fall and atmospheric conditions, (2) the coil and piping design which depends on heat transfer from a panel and on friction loss in piping due to the circulating medium used, and (3) the selection or design of a heat exchanger for heating the cir culating medium. 566 CHAPTER 24 1954 Guide DESIGN /- Heating Requirements The heating requirements for snow melting are afffe_cUteirdfb01y1v-fooufmrGaet.mos pheric factors: (1) rate of snowfall, (2) air temperature, (3) wind velocity, and (4) humidity. The effects of these factors can be evaluated by con sideration of the action of snow falling on.a wanned surface. ; The first flakes 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 evaporate. 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. Both the mass and heat transfers , attain a maximum only when the film is entirely free.of snow. Theoretically this is impossible because some time will elapse while the show is warmed to 32 F: For all practical 9% pipe on it m 1 -r 16.Fig. Detail op Snow Melting Panel F -- Depth of Finish Coat--Assumed as ^ in. of concrete. Finish Coat may be asphalt but then cover ' slab should be reduced from 3 in. Depth of slab should always keep thermal resistance equal to 3 in. _ . of concrete. S = Depth required by structural design.' purposes, however, it is permissible to assume the snow to be melted as fast as it falls. The surface is therefore considered entirely free of snow. The ratio of free area to total area is known as the free area ratio, <j>. When <)> -- 1, there is no snow oh the; surface and the mass and heat transfer is at a maximum. When <j> -- 0, the snow covers the entire area and there is no mass or heat transfer. At this time there are no data on the permissible values of <i> for various uses of snow melting systems. As a result, <j> is usually taken as unity or as zero. Since a very thin layer of snow will reduce <f>, but will not be objectionable, the selection of <t> = 1 provides a safety factor in the de sign. Until such time as <j> can be evaluated by tests, it is good practice to use <t> -- 1 for bridge ramps, public walks, emergency exits, etc. For private drives and walks where low installation costs are imperative, it may be permissible to use values of < of less than unity. For a more complete discussion of free area ratio, see Reference 6. The equations for the design of a snow melting system have been derived and explained in detail in Reference 7. The inclusion of <j> in the equations is explained in Reference 6. The four equations for the heating requirement are: 1. Sensible heat 9, to raise the temperature of the snow to 32 F q, = 2.6s (if -- l,) ff) Panel Heating 567 2. Heat of fusion qm to melt the snow . . 9m = 746s 3. Heat of vaporization 9, (mass transfer) 9.-= 1074 (0.0201b + 0.055) (0.185-p,.) <t> 4. Heat transfer 9h (convection and radition) (8) (9) 9s = 11.4 (0.0201b + 0.055) (ti-i.) <i> (10) The equation for the required fluid temperature to provide an output of qa = <?a + ?m + <?e + 9h has been derived in Reference 7 and for con struction similar to Fig. 16, is . where tm -- 0.5 9o + if (11) p,, - vapor pressure of moist air, inches of mercury. ,. 9. = heat of vaporization, Btu per (hour) (square foot); 9b = heat transfer by convection and radiation, Btu per (hour) (square foot). 9m = heat of fusion, Btu per (hour) (square foot). 9o = heat output off surface of slab 9. + 9m + 9. + 9m Btu per (hour) (square foot). 9, = sensible heat transferred to snow, Btu per (hour) (square foot). s = rate of snow fall, inches of water equivalent per hour. f = air temperature, Fahrenheit. . fe = water film temperature, Fahrenheit. Im = fluid (water and anti-freeze solution), temperature, Fahrenheit. v = wind velocity, miles per hour. 4> = free area ratio. Values for s for certain cities are given in Table 3. Using the values for s given in Table 3, the appropriate values for (a and u, the values for 9o may be found in Table 4. In preparing Table 4, only values of p8V for relative humidities of 80 percent were used. The variation in qa and tm for humidities of 75, 80, 85 and 90 percent are given in Reference 6, and may be calculated by solving Equations 12 and 13. df,, = -537 (0.0201b + 0.055) 4, (12) dgo dp,, = -1074 (0.0201b + 0.055) <t> (13) After determining the total heating requirements (the slab output) it is necessary to make allowance for back and edge losses. -These losses- vary from 30 to 50 percent, depending upon the amount of insulation that is used. . \ When determining the size of heat exchanger required, the actual film coefficient of an anti-freeze solution must be used. The manufacturer must therefore be given data on the type of anti-freeze solution; its con centration, and the temperature range to be expected during operation. Pumping Head The pumping head for a snow melting system may be computed by hieans of hydraulic tables or formulas (see chapter on Fluid Flow) except Ji 1` \l : I: 1 ;i CHAPTER 24 1954 Guide Table 3. Snowfall Data fob Vabiops Cities* City Numbeb of Readings with Maximum Tempeeatuse in 8-Houb Period below Freezing at Various Snowfall Rates Snowfall Rate in E quivalent Inches of Water per Six Hours. _ Total Taken Assumed Design Snowfall6 Col .1 0.00 to 0.24 Col. 2 Albany, N. Y..................................................... Bismarck, N. D.................................................. 2052 463 1640 2838 1300 0.25 to 0.49 Col. 3 29 5 4 0 3 0.50 to 0.74 Col. 4 0.75 to 0.099 Col. 5 Col. 6 5 1 3720 1 0 3536 0 0 3532 10 0 3720 0 0 3720 s Col. 7 0.16 0.08 0.08 0.08 0.08 1323 1871 2390 1363 1498 1045 1569 1351 1207 1830 916 1514 1189 2370 2703 11 23 9 19 3 3 2 4 4 5 5 44 12 5 7 4 3 0. 1 0 0 0 1 0 2 1 9 2 2 0 2 1 0 0 1 0 0 0 0 0 1 3 1 0 0 3720 3720 3720 1672 2976 3720 3720 3720 3720 3720 3720 3720 3720 3720 3720 0.16 0.16 0.08 0.16 0.08 0.08 0.08 0.08 0.08 0.08 0.25 0.16 0.08 0.08 613 8 4 0 3720 0.16 1795 8 1 0 3720 0.16 891 10 2 1 3720 0.16 1365 6 2 0 3720 0.08 2054 33 4 1 3720 0.16 1088 5 0 1 3720 0.08 1482 5 0 0 3720 0.08 1545 11 1 0 3720 0.16 |533 7 2 1 3348 0.16 0.16 dai*lyDfraotma frNoomveVm. bSe. rW1e5attoheFr Beburreuaaury, 15ttafrsoemao1n94re0atouiu1&9a49u. a&(cWuhae. rueutbh.eaut.o,_ta__l_r_e_a__d_in__g_s__a_,r_e__le__s_s__'than 3720 the period of record is less than 10 years). The difference between Col. 5 and the sum of readings in Cols. 2, 3, 4, and 5 is the number of readings with a maximum temperature (in the 6-hr period) above freezing. b The design rate is found as follows: Proceed to left (on line from any city) from Column 5 until the column containing the tenth reading is found. Assume that the larger value in the heading of the selected . column is an average maximum value, and should be multiplied by 2 to obtain the maximum rate for a 5-hour period. This maximum rate divided by 6 is the design rate per hour. This is equivalent to dividing the larger value in the heading of the selected column by 3. For example: For Albany, N. Y. Columns 5 and 4 total six readings, and consequently the tenth reading is in Column 3, which has the larger value of 0.49 in the column heading. .Dividing 0.49 by. 3,, the design water equivalent of 0.16 inches per hour is found, as listed in Column 7. . * New York City record was not used i n this tabulation since the records for that station were not com parable with those of the other stations. -. that allowances must be made for the physical properties of the circulating fluid. This fluid may be an aqueous solution of ethylene glycol, or it may be a petroleum distillate. In either case, the manufacturer should be contacted for the physical properties. Ethylene glycol solutions should Panel Heating 569 s Rate of Snowfall = OF Velocity v 5 10 15 I* = 10 F. Velocity v 5 10 15 t= 20 F Velocity t> 5 10 15 0.08 1.0 Co 151 205 260 127 168 209 102 128 154 tm 108 135 162 97 117 138 85 97 110 0.16 0.0 Cotm 66 66 66 64 64 64 62 . 62 62 66 66 66 65 65 65 64 64 64 i.o Co 218 273 327 193 233 274 165 191 217 tm 142 169 198 129 149 170 117 129 142 0.25 0.0 Co 133 133 133 129 129 129 125 125 125 tm 99 99 99 97 97 97 95 95 95 1.0 Co 292 347 401 265 305 346 235 261 287 tm 179 206 234 165 186 206 151 163 176 0.0 Co 208 208 208: 202 202 202 195 195 195 - - fm __ 137 137 137 134 134 134 131 131 131 ______ ______^vi wu nwuvt; Aiuunauy oi ou percent lor all air temperatures. a = Rate of snowfall, inches of water equivalent per hour (See Table 3). - 0 *s Free area ratio. Co* Slab output, Btu per (hour) (square foot). = Air temperature, Fahrenheit. tm Fluid temperature, Fahrenheit. Based on construction as shown in fig. 16. v Wind velocity, miles per hour. 30 F Velocity v ' 5 10 15 76 84 94 70 75 79 GO 60 60 63 63 63 135 144 154 100 105 109 121 121 121 93 93 93 203 212 221 134 139 144 188 188 188 127 127 127 contain a rust inhibitor (probably triethanolamine phosphate), and this will affect the properties slightly. For large installations, the friction losses should be calculated by the Fanning equation where ' 2gd ht = the loss 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 ~ the acceleration due to gravity = 32.174 ft per (second) (second). d = the internal diameter of the pipe, in feet. / = a dimensionless friction coefficient. (14) The factor / can be determined from the Moody chart which is Fig. 4 of Chapter 4, Fluid Flow. In determination of the Reynolds number, the effect of the inhibitor should be taken into account. The manu facturer of the anti-freeze solution must therefore be consulted. For approximate data for ethylene glycol without an inhibitor and for. a light oil, see Table 5. .. For small installations requiring less than 1 hp pump capacity, it may be satisfactory to compute the pump head required from friction loss tables for hot water heating systems, as given in Chapter 22, and to cor rect for the effect of. the anti-freeze solution. , Generally, hydraulic tables are prepared for water at 60 F and, 10 to 15 year old pipe. Since the circuit will be closed and the pipe will not scale 570 CHAPTER 24 1954 Guide or deteriorate, theage allowance on the pipe will probably be a sufficient allowance for the anti-freeze. If there is no age allowance, but the table is for 60 F water,; then the following allowances for heated anti-freeze solutions will be adequate: . 1. For fluid temperatures less than 100 F, add 15 percent. 2. For fluid temperatures between 100 and 130 F, add 10 percent. . 3. For fluid temperatures above 130 F, no allowance. If friction data for higher temperature water are used as a basis, the allowances needed will be much greater. If the systein is'operated intermittently, fluid temperatures may drop to the. freezing protection point. At that temperature, the fluid may be Table 5.Puyswai, Pbopebties ovAnti-freeze Solutions Solution Ethylene Glyool* Freezing Protection. Temp., F. --40 --40 %Bt Volume 31.4 42.7 51.2 100 Fluid Temperatube. 80 ( 120 I 160 j ________________ ------------- - -- --------------- - ,xW* to 1.92 0.839 65.1 1.14 0.854 64.4 0.77 0.871 63.6 0.56 0.829 62.7 M X 10* to 2.55 0.813 66.0 . 1.46 0.832 65.3 0.95 0.856 64.4 0.6S | 0.883 63.4 ,, X 10` to ft X 10* to 3:i6 1.77 0.788 0.809 66.8 65.9 _________ 6.60 0.426 1 60.7 3.13 0.444 59.8 1.14 0.835 . 65.0 ---------------2.06 | 0.462 59.0 * Interpolated from Reference 9. b From Socony-Vacuum Oil Co. - 0.000056 ft* per sec.) ' ft = kinematic viscosity, (feet squared per second) (e.fj. for oil at 80 F, 4 * ~ specific heat, Btu per (pound) (Fahrenheit degree). 10 *= specific ^weight, pounds per cubic foot. so viscous as to prevent the pump from discharging. If such conditions are expected the pump manufacturer should be consulted for advice in selAenctointhgetrhealplouwmapn.ce must he made in sizing the pump for anti-freeze; the volume of fluid to be pumped must be increased because of its low specific heat. Table 5 lists typical specific heat values, but here again, on large jobs the manufacturer should be consulted for accurate data on his product; . 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 8. SaSfeintyce ethylene glycol is slightly toxic, the system should be installed and. maintained independently. There should be no permanent connec tion hetweien the snow melting system arid the drinking water supply- Panel Heating 571 Ethylene glycol is not considered flammable. In fact; aqueous solu tions 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 a flash point between 260 and 280 F. When using fluids of this type, care should be taken to collect any oil dripping from the packing seal on the pump. Internal Corrosion . Ethylene glycol solutions tend to become corrosive in service; therefore, rust inhibitors are generally included!; Even with an inhibitor, the solu tion should be tested annually to determine any change in acidity; If the test indicates that the 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 psig steam. Tempera tures above 300 F accelerate the deterioration of the inhibitors; Slab Construction .. . - It has been found satisfactory to use '/'i pipe or tubing on 12-in. centers as a standard coil. If pumping-loads require a reduction in friction the pipe size may be increased to 1-in., but the slab depth must be increased ac cordingly. The piping should be supported in such a manner that there is a minimum of 2 in. of concrete aboye and below the pipe. This requires a 5-in. slab for %-in. pipe and 5%-in. for 1-in. pipe. If an insulating material is used; it is generally good practice to provide a moisture barrier between the insulation and the fill; A roofing material (such as a 55 lb. felt) is often used as a moisture barrier; The joints should be mopped, and the fill made smooth enough so that there will be no holes or gaps for moisture transfer. Also, the edges of the barrier should be flashed to the surface of the slab so that the ends are sealed. See Fig. 16. If the pipe must pass through an expansion joint; a protective coating should be applied to the pipe for a foot or two on both sides of the joint. If the pipe is kept dry at all times in both summer and winter, no ex ternal corrosion problems will occur. 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 the anti freeze becomes corrosive it must be drained. It is not good practice to re'y 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 antici pate this condition and add extra piping in these areas. If possible, coils should be added in the vertical surface. Another expedient is to carry CHAPTER 24 1954 Guide 572 the drainage to the area expected to be drifted. The drainage will tend to wash away some of the snow. / Example 1: Design a snow melting system for an area of 10,000 sq ft in Pittsburgh, Pa. Assume an air temperature of 10 F and a wind velocity of 10 mph. ' Solution: From Table 3 select a snowfall rate of 0.08. From Table 4 find the heat output of top of slab as = 168 Btuh per sq ft and the anti-freeze average circulating temFpoerra10tu,0r0e0assqInf.t =and11470Fp.ercent loss. from back of slab, the heat exchanger must delUivseirng10a,02000FXde1g68teXmp1e.4ra0tu-re2d,3r5o2p,0, 0th0eBetuxhit.temperature from the exchanger must be T12h7eFaanntid-frteheezeenstroalunctieontesmhpoeurldatbueresmuiutasbtl.ebefo10r7--F2.0 F minimum temperature for Pittsburgh, and will therefore have a specific heat (see Table 5) of 0.832, and a weight of 65.3 lb per cu ft. The quantity of solution to be circulated with 20 deg temper ature drop will then be 2,352,000 20 X 0.832 141,300 lb. per hr, whAicshsuemqueatlhs a27t0thgepmco, iol rc0ir.6c0u1itcouffltonpgeer ssteec.quivalent length is 250 ft and has a flow of 4 gpm. The coil is % in. IPS, having an internal diameter of 0.824 in.'or 0.0687 ft. The velocity is therefore . 60 (0-482X4)'23U1/4) 12 ' PS From Table 5 the kinematic viscosity p is 1.46 X 10~` ft' per sec. The Reynolds number N,,a. = F--d = 2Y.441g (X0.0l6(8F7*) = 11340` From Fig. 4 of Chapter 4, using a roughness factor e = 0.00015, whence e/d = 0.00218, the value of the friction factor/is found to be 0.0335. Substituting in Equation 14 for /, l, V and d = 0-0335 (250) (2.41)' ` = 2(32.2) (0.0687) = 11 *" ' The head against which the pump must operate is. therefore 11 ft of the, circulat ing liquid. . REFERENCES 1 Standard Specifications for Gypsum Plastering, including Requirements for Lathing and Plastering (American Standards Association, A42.1, 1946). ' Code and Manual for the Design and Installation of Warm Air Ceiling Panel Sys tems (Manual 7-A of the National Warm Air Heating and Air Conditioning Associ Various investigations of W. Nusselt (1915-1928) as discussed in Chap. 23 and aCthioanp).. 25, and tabulated in Author Index of Heat Transfer, by Max Jakob, Vol. I, 194*9T(hJoehTnraWnsilemyisasniodnSoofnHs,eNaet wbyYRoarkd)i.ation and Convection, by Ezer Griffiths & A. H. Davis (Special Report No. 9, 1922, Department of Scientific & Industrial Research, His1 MRaadjeiasttiyo'sn SatnadtioCnoenrvyeOctfifoicnef,rLoomndSounrf,aEcensgilannVda).rious Positions, by G. B. 'Wi_lkes and6 DCe. sMig.nFC. oPnedteitriosonns f(oArSSHnVowEMTerlatinnsga,cbtyioWn.sP, V. Cohl.a4p4m,1a9n38(H, peaagtieng51a3n)d. Ventilating, No'veDmesbiegrn, 1o9f5S2n, opw. 8M8)e.lting Systems, by W. P. Chapman (Heating and Ventilati.ng, Av8riAl,n1ti9-5F2r,epe.ze95P).rotection for Snow Melting Systems, by P.. B. Gordon (Official Panel Heating 573 Bulletin, Healing, Piping and Air Conditioning Contractors National Association, February, 1950, p. 21). 5 Properties of Ethylene Glycol and Its Aqueous Solution, by C. S. Cragoe (National Bureau of Standards CRC Report No. S, Society of Automotive Engineers). BIBLIOGRAPHY Trend Curves for Estimating Performance of Panel Heating Systems,, by B. F. Raber and F. W. Hutchinson (A.S.H.V.E. Transactions, Vol. 48,1942, p. 425). A.S.H.V.E. Research Report No. 1192--Panel Heating and Cooling Performance Studies, by B. F. Raber and F. W. Hutchinson (A.S.H.V.E. Transactions, Vol. 48, 1942, p. 35). . A.S.H.V.E. Research Report No. 1193--Radiation as a Factor in the Feeling of . Warmth in Convection Radiator and Panel Heated Rooms, by F. G. Houghten, Carl Gutberlet and E. C. Hach (A.S.H.V.E. Transactions, Vol. 48, 1942, p. 65). Panel Heating and Cooling Analysis, by B. F. Raber and F. W. Hutchinson (A.S.H.V.E. Transactions, Vol. 47, 1941, p. 285). , Operating Results of a Residence Radiant Wall Heating System, by E. J. Rodee (A.S.H.V.E. Transactions, Vol. 47, 1941, p. 123). _ Performance of a Residential Panel Heating System, by H. F."Randolph and J. B. Wallace (A.S.H.V.E. Transactions, Vol. 49, 1943, p. 235). Radiant Heating (Heating and Ventilating, March, 1941, p. 35). Radiant Heating and Cooling, by F. E. Giesecke (Healing, Piping and Air Condi tioning, June, July, August, September and October, 1940). Calculations for-Radiant Heating, by T. Napier Adlam (Heating and Ventilating, October, 1931). Radiant Heating and Cooling, Part I, by C. O. Mackay, L. T. Wright, Jr., R. E. Clark, and N. R. Gay (Cornell University Engineering Experiment Station, Bulletin No. 32, 1943). Design Method for Panel Heating Systems Using Copper Tubing, by R. G. Vander- weil (A.S.H.V.E. Journal Section, Heating, Piping and Air Conditioning, Nov. 1947, p. 123). Air Temperature Gradients in a Panel Heated Room, by J. M. Ayres and B. W. Levy (A.S.H.V.E. Transactions, Vol. 54, 1948, p. 131). Graphical Solution of Radiant Panel Areas, by W. P. Chapman and R. E. Fischer (Heating and Ventilating, Jan. 1948, p. 88). Embedding Coils in Radiant Heating Panels, by D. L. Mills and L. J. LaTart (Heating and Ventilating, Dec. 1947, p. 75). Radiant Heat with Copper Tubing, by D. L. Mills and L. J. LaTart (Heating and Ventilating, Nov. 1947, p. 95). Panel Heat with Copper Tubing--Experiment in Practice, by D. L. Mills andL. J. LaTart (Heating and Ventilating, Oct. 1947, p. 65). Experimental Studies on Panel Heating Tube Spacing, by B. F. Raber and F. W. Hutchinson (A.S.H.V.E. Transactions, Vol. 53, 1947, p. 369). Panel Heating--A Basic Discussion, by S. Konzo (American Artisan, Oct. 1946, p. 68). . Solar House Heated by a Warm Air Floor Panel, by John E. Peterson (American Artisan, Dec. 1946, p. 83). Design Data for a Warm Air Floor Panel, by Axel B. Algren (American Artisan Jan. 1947, p. 141). T The Mechanism of Heat Transfer, Panel Cooling, Heat Storage, by Charles S. Leopold (Refrigerating Engineering, July 1947, p. 33) Radiant Heating--Simplified Design and Installation (Copper and Brass Research Association, 1949). . Research Report No. 1387--Laboratory Studies on Heat Flow Within a Con crete Panel, by C. M. Humphreys, H. B. Nottage, C. V. Franks, R. G. Huebscher, L. F. Schutrum and D. W. Locklin (A.S.H.V.E. Transactions, Vol. 56, p. 175). Research Report No. 1388--Heat Flow Analysis in Panel Heating or Cooling Sections, by L. E. Hulbert, H. B. Nottage and C. V. Franks (A.S.H.V.E. Trans actions, Vol. 56, 1950, p. 189). . Electric Analogger Studies on Panels with Imbedded Tubes, by Carl F. Kayan (A.S.H.V.E. Transactions, Vol. 56, 1950, p. 205). Books . Water Heating, Radiant Heating and Radiant Cooling, by F. E. Giesecke (Tech nical Book Co., P. O. Box 62, Austin, Tex. 1947). CHAPTER 24 1954 Guide 574 , Panel Healing and Cooling Analysis, byB. F.'Raber and F. W.Hutchinson (John Wiley and Sons, New York, 1945). . /' ' Radiant Heating, by T. Napier Adlara (Industrial Press, 148 Lafayette St., New YoRrakd1ia9n47t )H: eating, by R. W. Shoemaker, 1948 (M-cGraw-Hill Book Co., New York). Chapter V (pages 103-115) of Heating and Air Conditioning, by J. R. Allen, J. H. Walker, and J. W. James (McGraw-Hill Book Co", New York--Sixth Edition, 1946). . Chapter 12, (pages 363-392) of Heating, Ventilating and Air Conditioning Funda mentals, by W: H. Severns and J. R. Fellows (John Wiley and Sons, New York, Second Edition, 1949): ' ! '. CHAPTER 25 , UNIT HEATERS AND UNIT VENTILATORS Definitions; Unit Heaters: Classification, Application, Ratings, Location, Space Temperatures, Control, Piping, Maintenance Boiler Capacity; Unit Ventilators: .. Ratings, Capacity Requirements, Application, Selection, Control, Location, Exhaust Flues; Window Ventilators ,1: DESCRIPTIONS of heating, cooling, ventilating, humidifying, and dehumidifying systems are given in other chapters: This chapter deals with unit heaters and unit ventilators. Unit air conditioners and unit coolers are discussed in Chapter 26. ,! : Definitions The generally accepted meaning of the word unit in the terms unit heat ers, unit ventilators, and unit humidifiers, is that of a factory-made en cased assembly of the functional elements indicated by Its name. Such units can be shipped complete or in sections, so that, the only field work necessary is the assembling of the sections,- providing proper supports, and connecting the unit to sources of heat (or fuel), power and water supply and, if necessary, to vent pipes for combustion gases. 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, a housing, and outlet vanes or diffusers. Some types are shown in Figs. 1 to 4. : , :, : The term unit ventilator denotes an assembly, the principal function of which is to ventilate and cool the space by the introduction of outdoor air. It may serve to heat and circulate the air within the space, or introduce air from outdoors, or may accomplish bothun varying proportions. The essential elements of a unit ventilator are fans and motor, heating element, dampers, and outlet grilles or diffusers, all encased in a housing. Classification UNIT HEATERS The various types of unit heaters which are at present available can usu ally be classified according to one of the three following methods: l. By type of healer. Under this classification there are three types of heating elements to be considered: (a) the steam, or hot water type, (6) the electric type, and (c) the direct fired type which day be gas, oil,'or coed fired. 2. By type of fan. Under this classification there are two types of fans to be considered: (a) the propeller type1 and (b) the centrifuged type. Either type may be arranged for horizontal or vertical delivery of air. 3. By arrangement of elements. Under this classification there are two types of heaters to be considered: (a) the draw-through type, in which the fan draws air through, and (b) the blow-through type, in which the fanblows air through the heater. : Unit heaters are available in any combination of the three preceding gen- 575 CHAPTER 25' 1954 Guide "Unit Heaters and Unit Ventilators 576 577 eral classifications. For example, the steam or hot water type may be secured with either the propeller or centrifugal type of fans, and in either the draw-through or blow-through type. - Unit heaters also vary in other minor respects. For example, steam and return inlets and outlets may be located on top and bottom, respectively, or on the same side of the unit. Some units are supported by the piping and some have independent supports. The heating surface of steam or water type units is generally made up of a non-ferrous tube-and-fin assem bly; or it may be fabricated of steel, or cast in steel or iron. Application of Unit Heaters There are three major factors to consider in the application of unit heat ers, namely: (1) heating medium, (2) air.distribution, and (3) location of .unit. ' Steam or hot water unit heaters are used principally for heating com mercial and industrial structures such as garages, factories, laboratories, and stores. They may also be used for heating finished rooms, if properly applied and concealed, and if some'consideration is given to the problem of noise. Unit heaters may also be adapted to a number of industrial processes, such as drying and curing, in which the use of heated air in rapid circulation with uniform distribution is of particular advantage. They may be used for moisture absorption, such as fog removal in dye houses, or for the pre 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 unit heaters draw air from outside in enough volume to provide a rapid air change, and that they operate in conjunction with ventilators or fans for exhausting the moisture-laden air. (See discussion of condensation in Chapter 10.) Electric unit heaters can be used to advantage for supplemental heat in residences, for the heating of ticket booths, watchmen's offices, factory offices, locker rooms, and other isolated rooms scattered over large areas. They are particularly useful in isolated and untended pumping stations or pits where they may be thermostatically controlled to prevent freezing temperatures. . Gas-fired unit heaters find application in industrial plants, offices, stores, garages; in fact, in almost every location where steam-type units are usedThe installation cost of gas-fired units is usually less than that of a type requiring that a new boiler be installed, unless the number to be installed would justify the cost of a boiler and steam or hot-water unit heater system. Oil-fired unit heaters are used in industrial plants, garages and commercial buildings. Coal-fired unit heaters are used principally in large industrial plants such as foundries. Outlet Velocities . Outlet velocities of unit heaters vary from about 400 to 2500 fpm, depend ing upon the type of unit and the distance (blow) to which the air to is be Projected. Noise and drafts must be considered in the choice of air veloci ties, since both generally increase with increase of air velocity. In the selection of unit heaters it is important to ascertain that the blow and coverage wp sufficient. The blow is dependent to a marked degree on 578 CHAPTER 25 1954 Guide the temperature of air leaving the heater, as well as upon its velocity. (See discussion under heading of Inlet, Outlet, and Space Temperatures with Unit Heaters.) Recommended coverage and mounting heights should be obtained from the manufacturer. Air Outlets . In order to obtain the desired air distribution and heat diffusion, unit heaters are commonly equipped with directional outlets, adjustable louvers, or fixed types of diffusers. . ;. Ratings of Unit Heaters . It is standard practice to rate unit heaters on; the basis of the amount of heat delivered by the air in Btu per hour above an entering air temperature of 60 F. This applies to all types of unit heaters, the steam or hot water type, the electric type and the direct fired type. There are* however, other factors which must be taken into account, especially when an attempt is made to compare one type of heater with another. .These are the tem perature of the heating element and the velocity of air through it. Con sideration is given to these factors in the discussion of ratings for each type of unit heater in the following paragraphs. Steam. Rating of steam unit heaters has been standardized by a code2 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 resist ance to air flow. . The capacity of a heater increases as the steam pressure increases, and decreases as the entering air temperature increases. The heating capacity for any condition of steam pressure and entering air temperature other than standard may be calculated approximately from any given rating by the use of factors in Table 1 for the blow-through or draw-through types. Hot Water. A standard for the rating of hot water type unit heaters has also been established by code3 in which the following items are the basis of rating: entering water at 200 F; entering air at 60 F (29.92 in. Hg baro metric pressure); and heater operating free of external resistance to air flow. This code also prescribes a method of translating the output in Btu and the temperature rise as obtained under test conditions to stand ard conditions of air and water temperature. Electric. Electric type unit heaters are available in sizes up. to at least 60 kw capacity. They consist of resistance type heating elements combined with fan and motor, together with a suitable casing. Electric unit heaters are rated on the energy input to the heater, expressed in terms of kilowatts, Btuh or EDR (Equivalent Direct Radiation). Gas-Fired. Gas-fired unit heaters are built in both suspended and floor models, with either propeller or centrifugal type fans. They are rated in terms of both input and output in accordance with the approval require ments of the American Gas Association. . Oil-Fired. The oil-fired unit heater is usually equipped with a centrif ugal fan or fans and is available in either the floor-mounted or in smaller sizes in the suspended type. Ratings are based on heat delivered at heater outlet in Btu per hour. Stoker-Fired. The stoker-fired unit heater can be obtained in a wide range of capacities. Ratings are based on heat delivered, at the heater outlet in Btu per hour. Unit Heaters and Unit Ventilators 579 Table 1. Constants for Determining the Capacity of Unit Heaters fob Various.Steam Pressures and Temperatures of Entering Air ; (Bated on Sleam Pressure of t pVip and Entering Air'Temperature of 80 F) Steam Pbeb- psig -10 0* Temperature or Entering Air io- 20. 30. 40* 50* 60* 70* 80* 90* 100* .0 1.54 1.45 1.37 1.27 2.29 T.13 1.03 0.96 0.68 0.81 0.74 0.67 2 1.59 1.50 1.41 1.32 1.24 1.16 1.08 1.00 0.93 0.85 0.78 0.71 5 1.64 1.55 1.46 1.37 1.29 1.21 1.13 1:05 0.97 0:90 0.83 0.76 10 1.73 1.64 1.55 1.45 1.38. 1.29 1.21 1.13 1.06 0.98 0.91 .0.84 ,s 15 1.80 1.71 1.61 1.53 1.44 1.34 1.28 1.19 1.12 1.04 0.97 0.90 a o aH . . .20 1.86 1.77 1.68 T.58 1.50 1.42 1-33 1.25 i:i7 1.10 -1.02 0.9530 1.97 1.87 .1.78 1.68 1.60 1.51 1.43 1.35 1.27 1.19 1.12 1.04 40 2.06 1.96 1.86 1.77 1.68 1.60 1.51 1.43 1.35 1.27 1.19 1.12 50 2.13 2.04 1.94 1.85 1.76 .1.67 1.58 1.50 1.42 1:34 1.26 1.19 60 2.20 2.09 2.00 1.90 1.81 1.73 1.64 1.56 1.47 1.39 1.31 1.24 70 2.26 2.16 .2.08 1.96 1.87 1,78 1.70 1,61 1.53 1.45 1.37 1.29 75 2.28 2.18 2.09 1.99 1.90 1.81 1.72 1.64 .1.55 1.47 1.40 1.32 80 2.31 2.21 2.11 2.02 1.93 1.84 1.75 1.66 1.58 1.50 1.42 1.34 90 2.36 2.26 2.16 2.06 1.97 1.88 1.79 1.71 1.62 i:54 1.46 1.38 100 2741 2.31 2.20 2:11 2:02 1.93 1.84 1.75 1.66 1.58 1.60 1:42 125 2.51 2.41 2.31 2.21 2.11 2.02 1.93 1.84 1:76 1.68 1.59 1.61 150 2.60 2.50 2.40 2.30 2.20 2.11 2.02 1.93 1.84 1.76 1.67 1.59 *H oa Do ' aH a< Q - : 0 1.48 . - 2 ... 1.52 5 1.57 10 1.64 .15 1.69 1.41 1.33 1.44/ .1.35 1.49 1.41 1.56 1.48 1.61 1.53 1.25 1.29 1.33 1.40 1.46 1:18 1.22 1.28 1.33 .1.38 1.11 1.14 2.18 1.25 1.31 1.03 1.07 1.11 1.18 1.24 0.96 1.00; 1.05 i.ii 1.17 0.89 0:93 0.98 1.04 1.10 0.82 0.88 0.910.97 1.03 0.75 0.79 0.84 0.90 0.96 0:69 0.73 0.77 0.84 0.90 20 30 40 50 60 - 1.73 1.80 1.86 1.93 1.97 1.65 1:73 1.79 1.85 1.90 1.57 1.65 1.71 1.77 1.82. 1.50 1.57 1.64 T.70 1.75 1.42 1.50 1.56 1.63 1.67 1.35 1.42 1.49 1.55 1.60 1.28 1.35 1.42 .1.48 i .53 1.21, 1.14 ,1.07; 1.28 1.21 1.15 l.to tT2fT 1^22* 1.42 1.35 1.28 1.46 1:40 1.33 i;00 1.08 1.15 i.2i 1.26 .0.94, 1.01 b08 1.15 1.19 70 2.02 1.94 1.87 1.80 1.72 1.65 1.58 1.51 1.44 1.38 1.31 1.24 75 2.04 1.97 1.90 1.82 1.75 1.68 1.61 1.54 1.47 1.40 1.33 i:27 80 2.06 1.99 1.91 1.84 1.77 1.70 1.63 1.56 1.49 1.42 U35 1.29 90 2.10 2.03 1.95 1.88 1.80 1.73 1.66 1.59 1.52 1:46 1.39 1.32 100 2.15 2.07 1.99 1.92 1.85. 1-77 1.70 1.63 1.56 1.49 T.43 1.86 125 .--__ _____ 150 2.21 2.28 2.14 2.06 2.20 1 2.13 1.99 2.05 1.91 1:98 1.84 1.91 1.77 1.84 ,1..7770 | 1.63 1.70 1.56 1.63 1.49 1.56 1.43 1.50 Mote. To determine capacity at any steam pressure and entering temperature, multiply rated capacity at 60 F entering air and 2 psig by constant from table. ' When increasing steam pressure it is important to determine whether the heater is suitable for the increased pressure application, and whether the resulting increased outlet temperature u satis factory. . Effect of Resistance Upon Capacity ` Unit heaters are customarily rated as free delivery type units. If out side air intakes, air filters, or ducts on the inlet or discharge are used, a reduction in air and heating capacity will result because of this added resistance to air flow. The percentage of this reduction in capacity will depend upon the characteristics of the heater, and on the type, design, and 580 CHAPTER 25 1954 Guide speed of the fans, so that no specific percentage reduction can be assigned for all heaters at a given added resistance. The heat output to be expected under other than free delivery conditions should be secured from the manu facturer. Location of Unit Heaters Care should be taken in the location of unit heaters to insure free air circulation to the intake and proper heat distribution over the working level. Manufacturers' catalogs usually give suggestions for best arrange ments, of the various heaters. Types and makes of available heaters are shown in the Catalog Data Section of this volume. Hot blasts in working zones should have their discharge outlets above the head line, and suspended heaters should be so adjusted that the heated air stream will not be objectionable. ..In connection with the.use of vertical type unit heaters, care must be exercised in the selection of the heater. It has been found that the higher the unit is placed above the floor, the lower must be the outlet temperature of the air leaying the heater in order that the heated air may be forced into the occupied zone. Inlet, Outlet and Space Temperatures with Unit Heaters In the selection of unit heaters for any particular design, consideration should be given to the temperature of air entering the heaters, as well as the temperature to be maintained in the working zone of the space. In general, the temperature differences per foot of elevation, when .using unit heaters, are less than corresponding variations when using direct radiation.4 High velocity units will maintain slightly lower temperature differences than low discharge velocity units. Correspondingly, units with lower dis charge air temperature will maintain lower temperature differences than units with higher discharge temperatures. Directional control of the dis charged air from a unit heater can be an important factor, added to qualities of reasonably good outlet velocity and outlet temperature, in effecting satisfactory distribution of heat and reducing floor-to-eeiling temperature difference. : Since the outlet temperature of air from a .unit heater increases with the temperature of the heating medium, such as high pressure steam, heaters can be obtained with heating elements having less than the regular amount of heating surface in order to obtain, with the high temperature heating medium, approximately the same leaving air temperature as would be ob tained from a lower temperature heating medium. When some outside air is introduced, the temperature of the mixture of outside and recirculating air must be calculated and used as the entering air temperature at the heater. Unit heaters connected in this manner per form the function of unit ventilators. For a discussion of this function see the section of this chapter entitled Unit Ventilators. For recirculating heaters located at the floor or with intakes at the floor, the temperature of air entering the heater should be assumed to be the same as that to be maintained in the room itself. Automatic. Control of Unit Heaters Thermostatic control of unit heaters may be accomplished either by starting and stopping the fan, or by controlling the flow of the heating, medium to the heating element. Unit heaters may be used in summer as Unit Heaters arid Unit Ventilators 581 Fio. 5. Unit Heater Connection to Low Pressure Steam Gravity System a means of circulating air to give some measure of comfort due to air mo tion. In such cases the heating element should be shut off from the source of heat. The. thermostat should be provided with a by-pass switch which will permit the fan to be operated independently of the room temperature. '. \ Piping Connections For Steam 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 requirements while at the same time permitting the heaters to function as intended. The basic piping principles for steam systems are discussed in Chapter 21. - Rapid condensation of steam, especially during heating-up periods, is characteristic of this type of equipment. The return piping must be planned to keep the heating coil free of rapid condensation, while 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, heater fan is operated under start-and-stop control, and where all or part of the air is taken from the outside. In such installations the condensation rate may vary rapidly, and the necessity for aniple pipe capac ity is particularly important. ....... Piping connections for unit heaters as recommended by the Industrial Unit Heater Association are shown in Figs. 5 to 9. . In steam systems the branch from the supply main to the heater should Pio. 6. Unit Hbateb Connection fob Vacuum os Vapor Steam System 582 CHAPTER 25 1954 Guide ^ Fig. 7..,Unit Heater Connection to High Pressure Steam System pitch.toward the main, and be connected to.its top to prevent condensation in the main from draining through the heater where it might reduce capac ity and cause noise. `. ;: The return piping from steam 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 condensa tion to remain in the heater. . Dirt pockets shown in Figs. 5 to 7 are essential, and strainers are recom mended as an additional means of retaining 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. Strain-' ers should always be installed in the steam supply line if the heater is equippedWith the steam distributing type of coils. An adequate air vent is required for closed low pressure gravity systems. The vertical pipe connection to the air vent should be at least % in. I.P.S. to permit separation of the water from the air passing to the vent. In vacuum systems, if thermostatic instead of float and thermostatic traps are used, a cooling leg must be provided ahead of the trap. In high pressure systems it is customary to vent the air through a pet cock which is left slightly open at all times, Where possible it is advisable to install pressure reducing valves to permit operation of the heaters at lower pressure. Traps used must be suitable for the operating pressure, encountered. In connecting piping to hot water unit heaters, the piping should be Fig. 8. Connection of Horizontal Unit Heater to Hot Water System Unit Heaters and Unit Ventilators 583 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 if shutdown in freezing weather is possible. ' ... . 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 blow ing with high-pressure air, or by using a steam spray. Removal of the heating element and washing with a mild alkali solution, followed by thor ough 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 blades should be cleaned when necessary. Vibration may also be caused by improper fan position or loose set screws. Fig. 9. Connection of Vertical Unit Heater to Hot Water System There is considerable difference in the attention required by the various types of motors used with unit heaters. This is particularly true of lubri cation, the instructions for which must be carefully followed for trouble-free operation. Excessive lubrication may cause lubricant to reach and damage the rotor. An improper lubricant may cause failure of bearings. Instruc tions for care of the motor on any unit 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 atten tion specified by the manufacturer. If the unit is direct-connected, the couplings should be inspected periodically for wear and alignment. V-belt drives should have all belts replaced with a matched set if one beit shows wear. Periodical inspection 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 re placed when dirty. For prevention of corrosion in unit heaters, see Chapter 43, Corrosion and Water Formed Deposits, Causes and Prevention, in this edition, and *"0 Bulletin 12, The Care and Maintenance of Steam and Hot Water Unit Heaters, published by the Industrial Unit Heater Association. CHAPTER 25 1954 Guide BOILER CAPACITY FOR STEAM UNIT HEATERS The capacity of the boiler should be based on the rated capacity of the unit.heaters at the lowest entering air temperature and highest fan.-speed' that will occur, plus an-allowance for pipe line losses. It is unwise to in stall a single unit heater as the sole load on any boiler, particularly if the unit heater motor is started and stopped by thermostatic control. The wide and sudden fluctuations of load that occur under such conditions would require closer attention to the boiler than is usually possible -in..a. small installation. Where oil or gas fuel is used in the boiler, it'is possible by means of a pressure operated switch to control the boiler, in response to this WINDOW Unit Heaters and Unit Ventilators 585 employed as the heating medium. Unit ventilators are intended primarily for use in schools, meeting rooms, offices, or other applications where the density of occupancy indicates the need for ventilation. In normal opera tion, the discharge air temperature from a unit ventilator is varied in accordance with the room demands. Where a heating effect is required, the air delivered is above room temperature. Where the heat generated within the room by occupants, sun, etc., is sufficient to cause overheating, the air delivery temperature must be below that of the rooms. It is cus tomary to equip unit ventilators with control devices that prevent the delivery of air at a temperature that will cause cold drafts. Unit venti- Fio. 10. Typical Blow-Thbough Type Unit Ventilator Showing One of Many , Arrangements of Dampers and Heating Elements . . rapid fluctuation. In most cases, and particularly where, the boiler is coal- fired, it is advisable to use two or more smaller units instead of one large unit heater. '. . Steam pressures below 5 lb can be used with safety for recirculating unit heaters when their heating surfaces are designed for those pressures, and when proper provision is made for returning the condensate. If units receive air that may be at a temperature below freezing, a steam pressure of not less than 5 lb should be maintained in the heating element, or a corre sponding differential in pressure between the supply and return piping should be maintained by means of a vacuum. . UNIT VENTILATORS A unit ventilator as defined earlier in this chapter, has the function'of introducing outdoor air for ventilation and cooling in addition to heating. The typical unit is arranged to introduce outdoor air and recirculated air to the room in varying quantities and is equipped with a system of control, that permits both the heating and cooling effect to be varied while the fans are operating continuously. Either steam or forced hot water may. be Fig. 11. Typical Draw-Through Type Unit Ventilator Showing One of Many Arrangements of Dampers and Heating Elements lators maybe of the heating element or damper controlled type, constructed on the blow-through (Fig, 10) or draw-through principle as illustrated in Fig. 11. Ratings of Unit Ventilators Unit ventilators are customarily cataloged with two ratings: the anemom eter rating and the standard air rating. The anemometer air rating is peculiar to school house ventilation ana was for many years the standard by which school officials checked and specified unit ventilator capacities. It originated as a convenient field measurement for checking air quantities, and is the basis of rating for ventilation requirements under many state and local building codes. The anemometer rating (air capacity) is obtained by averaging the air velocities obtained by an anemometer 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 average velocity is sometimes obtained by moving the anemometer over the outlet 2 in. from its face.) The anemometer rating is based on the 586 CHAPTER 25 1954 Guide final temperature of'the air leaving the grille while the unit is delivering outdoor air and room air in the proper proportion and the heating'element is supplied with steam or hot water as specified. '; The standard air rating is obtained in accordance with the A.S.H.V.E. Standard Code for Testing and Rating Steam Unit Ventilators.6 This code requires that the following rating information be supplied: .Rating Factors to be SpecifiedThe rating of the unit ventilator shall specify: a. Final temperature at different entering air temperatures. . b. Total EDR at different entering air temperatures. . c. Air delivered by the unit in cubic feet per minute at the standard basis of rating with the fans operated at rated speed, with all air being blown through the heating unit, and with the standard louver and grille on the outlet. The Standard Basis of Rating shall be as follows: . a. Dry saturated steam at a temperature at the unit corresponding to an absolute pressure of 16.7 psi (218.5 F). b. Entering air temperature of zero Fahrenheit degrees. c. Volume delivered in cubic feet per minute converted to standard air at 70 F. Rating Tables for unit ventilators shall contain the following data in addition to the standard rating, for entering air temperatures from -- 30 F to +60 F: a. Inlet temperature, Fahrenheit degrees. b. Final temperature, Fahrenheit degrees. c. Total EDR at the specified entering temperature. d. Surplus or heating EDR at the specified entering temperature. Surplus or Heating Equivalent Direct Radiation for the purposes of this code shall be construed to mean difference between the total EDR at a specified inlet tempera ture and the EDR required to heat the air from that temperature to 70 F. Table 2 shows the air handling capacities by the two methods of rating and the approximate room heating equivalent in EDR of an intermediate size of heating element. Heating elements are available for either a higher or lower capacity. Heating Capacity Requirements for Unit Ventilators Since a unit ventilator has the dual function of introducing outdoor air for ventilation and maintaining a specified room temperature, the heat re quired by the unit may be similarly divided as (1) heat required for ventila tion (//v) and (2) surplus heat (Hs). The surplus heat is available for main taining room temperatures. If auxiliary radiation is installed, the surplus heat requirement may be reduced by a corresponding amount. The sum of Hv and H* is the total heat (Ht) to be supplied by the unit ventilator. These quantities of heat are related by the following equations: where A, = 0.24 W - Ht = 0-24 W (l, - to) ff. = flt - fly = 0.24 W (1, - () W = d 60 Q Ht = H, + 0.24 d 60 <? (1 - to). (1) (2) (3) (U (5) d = density of air, pounds per cubic foot (0.075 lb per cu ft for Standard Air by definition). fl. = surplus heat, Btu per hour. fly -- heat required to warm air for ventilation, Btu per hour. Ht = total heat requirements for both heating and ventilation, Btu per hour. Q = volume of air handled by the ventilating equipment, cubic feet per minute. Unit Heaters and Unit Ventilators t = temperature to be maintained in the room, Fahrenheit degrees; to = outside temperature, Fahrenheit degrees. t, = temperature of the air leaving the unit, Fahrenheit degrees. W = weight of air circulated, pounds per hour. 0.24 = specific heat of air at constant pressure (approximate value). 587 _____ ,----------------- - ....... w. .. ...I ,,on, luuiu io ,uuu mu per nour, and-the: venti lating requirements are 1000 cfm. If the room temperature is to be 70 F and all air is taken from the outside at zero, what will be the total heat demand on the unit if it is required to provide for both the heating and ventilating requirements (combined system)? Solution: Since the surplus heat is available to replace the heat loss of the room, fl, = 24,000 Btu per hour. Substituting in Equation 5: , : X 0.075 X 60 X 1000 (70 - 0) = 99,600 Btu per hour t, = 0.24 X 24,000 0.075 X 60 X 1000 + 70 = 92.2 F Table 2. Typical Capacities of Unit Ventilators fob an Entering Air _____________ ^` Temperature of Zero Cubic Feet op Aib per Minute Anemometer a Rating Standard Air Rating 750 1000 1260 1560 500 750 1000 1250 Total Capacity in Square Feet, Equivalent Di rect Radiation Capacity Available fob Heating the Room, Square Feet Equivalent - Direct Radiation 214 56 320 84 427 112 534 141 Final A-iti Temperature F Deo 95 95 95 95 If in Example 1 a 1000 cfm (Standard Air) unit were required, but only 25 percent of the air introduced were outdoor air, the solution is: Ht = 24,000 + 0.24 X 0.075 X 60 X 0.25 X 1000 (70 - 0) = 42,900 24,000 ' t, = -------------------- 5--------------------------(- 70 = 92.2 0.24 X 0.075 X 60 X 1000 . . ' The only difference from Example 1 is that, in the latter case, the ventila tion load has been reduced. Applications of Unit Ventilators . Items to be considered in the application of unit ventilators are: (1) combination with other means of heating, (2) selection of unit ventilator size, (3) cycle of control, (4) location of units; and (5) method of venting and exhausting. In a split system the unit ventilator heat output is supplemented by that of additional radiators or convectors, and consequently a correspond ing reduction in required unit ventilator heating capacity may be .made. With the split system, temperature control equipment should operate to clos.e the supply to auxiliary radiation or convectors as the first step in the control cycle on a rising room temperature. . The combined system employs a unit ventilator with sufficient heating 588 CHAPTER 25 1954 Guide capacity for both ventilation and normal heat losses. In such a case no direct radiation is required. The cost of installation of a combined system is usually less than that of a split system. The unit ventilator is normally arranged to circulate outdoor air constantly or to circulate room air con stantly up to full capacity; or to circulate mixed and variable quantities of room air and outdoor air automatically, depending on the thermal require ment of the room. The minimum amount of outdoor air for ventilation purposes may be governed by state or local codes or may be calculated by the engineer to meet the ventilating air needs of the particular application. Selection of Unit Ventilator Size The primary consideration in the selection of the size of unit ventilator is the number of occupants in the space. Other factors to be considered are state and local code requirements, volume of .the room, density of occu pancy, and the usage of the room. A safe rule for determining air capacity is to allow a total air quantity of 30 cfm per person, or six to nine room air changes through the unit, whichever is greater. With this quantity of air handled, it is possible to obtain satisfactory cooling in mild weather. Since cooling is an important function, the unit ventilator must be selected to supply adequate air quantities. After selecting the basic size of unit, the coil capacity to meet the heating requirement can be determined from the manufacturer's tables. Control of Unit Ventilators Three cycles of control are available for use with unit ventilators. These cycles of control determine the sequence of operation of the dampers and heating element as follows: Cycle X--All Outdoor Air. During the heating-up period, the damper remains closed to outdoor air and the unit ventilator recirculates room air. Just before the desired room temperature is reached, the room thermostat operates the damper to admit only outdoor air. No recirculation takes place during the periods of room occupancy. Cycle Y--A Variable Quantity of Outdoor Air with a Fixed Minimum. During the heating-up period, the damper remains closed to outdoor air and the unit venti lator recirculates room air. Just before the desired room temperature is reached, the room thermostat causes the damper to open to admit the desired minimum quantity of outdoor air, the balance of the air being taken from the room. As long as the minimum quantity of outdoor air is sufficient to prevent overheating, the damper . remains in this minimum position. If more outdoor air is needed for cooling, the damper, under control of the room thermostat and the air stream thermostat, is operated to increase the proportion of outdoor air as needed, up to the maximum. Cycle Z--A Variable Quantity of Outdoor Air without a Fixed. Minimum. During the heating-up period, the damper remains closed to outdoor air and the unit venti lator recirculates room air. Just before the desired room temperature is reached, the air stream thermostat, placed ahead of the heating element to control the mixture ot room air and outdoor air, assumes full control over the damper. Thereafter, this instrument positions the damper to maintain a predetermined constant-temperature mixture of indoor and outdoor air during all occupied periods. Meanwhile, the heat ing element, under the control of the room thermostat, adds just sufficient heat to the air mixture to maintain the desired room temperature. Location of Unit Ventilator The location of the unit ventilator in a room is important. Wherever possible it should be placed against an outside wall and on the center line Unit Heaters and Unit Ventilators 589 of the room. It is difficult to obtain proper air distribution if the unit is installed either on an inside wall or in a comer of the room. Standard units discharge the air stream upward, but for special cases units may be installed to discharge air horizontally.' Units may be set against the wall or par tially recessed into the wall to save space without materially affecting the results. Air Exhaust Vents and Flues The size and location of the air exhaust vent6 outlet are important and in many cases, are regulated by laws for public buildings. Where no codes govern, the location and size of vents are left to the discretion of the en gineer. Best results have been obtained with a velocity through the vent open ings nearly equal to that at which the air is introduced into the room,, thus Fig. 12. Typical Window Ventilator maintaining a slight pressure in the room. Calculated velocities at the vent openings of from 600 to 800 fpm produce the best diffusion results from this system. Many states, however, have regulations that will not permit velocities as high as 800 fpm. If a vent opening at or near the floor is near a desk or place where a person is seated, a velocity of 800 fpm in the vent opening will produce an objectionable draft. In such a case the veloc ity in the vent opening should not exceed 400 to 450 fpm, although duct velocities may be maintained at 600 to 800 fpm if codes permit. In school buildings provided with wardrobes or cloakrooms, the vents may be so located that the air passes through these spaces, ventilating them with air which otherwise would be passed to the outside without being used to the best advantage. Many state and local codes for ventilation of public buildings make this arrangement mandatory. WINDOW VENTILATORS A window ventilator illustrated in Fig. 12 consists of filter and switch controlled motor-driven fans enclosed in a cabinet to be mounted on the window sill. Such units accomplish ventilation, air cleaning, and air cir culation, but have no means of heating the air. The direction of air dis charge is manually adjustable for seasonal operation. 590 CHAPTER 25 1954 Guide , REFERENCES 1 See National Association of Fan Manufacturers standard definitions in Chapter 33. 1 Standard Code for Testing and Rating Steam Unit Heaters (A.S.H.V.E. Trans actions, Vol. 36,' 1930, p. 165), prepared by a Joint Code Committee of the American Society of Heating and Ventilating Engineers and the Industrial Unit Heater Association and adopted i930. Code revised 1950. 1 Standard Code for Testing Hot Water Unit Heaters prepared by Engineering Committee of Industrial Unit Heater Association. Adopted by Industrial Unit Healer Association August 1942 and published September 1942. 4 A.S.H.V.E. Research Report No. 958--Temperature Gradient Observations in a Large Heated Space, by G. L. 1,arson, 1). W. Nelson and 0. C. Cromer (A.S.H.V.E. Transactions, Vol. 39, 1933, p. 243).' A.S.H.V.E. Research Report No. 1011Tests of Three Heating Systems;in an Industrial Type of Building, by G. L. Larson, D. W. Nelson and John James (A.S.H.V.E. Transactions, Vol. 41, 1935, p. 185). 5 A S H.V E. Standard Code for Testing and Rating Steam Unit Ventilators (A.S.H.V.E. Transactions, Vol. 38, 1932, p. 25)(Effective Jan. 1, 1934). A.S.H.V.E..;Research Report No. 936--Investigation of Air Outlets in-Class Room Ventilation, by G. L. Larson, D. W. Nelson and R. W. Kubasta (A.S.H.V.E. Transactions,-Vol. 38, 1932, p. 463). A.S.H.V.E. Research Report No. 1017--Air Supply to Classrooms in Relation to Vent Flue Openings,, by F. C. Houghten, Carl Gutberlet and M. F. Lichtenfels (A.S.H.V.E. Transactions, Vol. 41, 1935, p. 279). CHAPTER 26 UNIT AIR CONDITIONERS AND UNIT AIR COOLERS Definitions, Classification of Unit Type Equipment, Component Parts of Unit Type Equipment, Sound Isolation, Modifications of Remote Units, Ratings of Unit Air Conditioners, Application of Unitary Equipment, Unit Air Coolers . THIS chapter presents the physical characteristics of air cooling units and air conditioning units; a suggested procedure for selection of units; and some of the factors, involved in the application of unitary equipment. In general, factory produced unit equipment' can be obtained to accomplish, all of the functions possible from field assemblies, but the advantages of unit equipment are most apparent in small, and moderate capacities. Above 12,000 cfm capacity, or approximately 40 tons of refrigeration capacity,, handling and assembly costs generally favor the use of field assembled units. Multiple application of unitary equipment is frequently justified for large gross tonnage installations where zoning or a minimum amount of air distributing ducts is desirable. DEFINITIONS , 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 committee1-2-8 on Rating Refrigerating Equipment has defined the various types of unitary equipment: 1. A Cooling Unit is a specific air treating combination consisting of means for air circulation and cooling within prescribed temperature limits.1 2. An Air Conditioning Unit is a specific air treating combination consisting of means for ventilation, air circulation, air 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 consist ing of means for ventilation, air circulation, air cleaning, and heat transfer, with control means for cooling and maintaining temperature and humidity within pre scribed limits.1 . 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. Selfcontained air conditioning units are classified8 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 outside, ventilation by exhausting room air to the outside, or ventilation by a combination of the last two methods), and method of discharging air to the room (free delivery or pressure type). 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 im pose air resistance. J- A Forced-Circulation Air Cooler is a factory encased assembly of elements by which heat is transferred from air to refrigerants.* CLASSIFICATION OF UNIT TYPE EQUIPMENT . Field assembled apparatus as described in Chapter 30 can be designed in shape, size, and capacity for any application, with the refrigeration and 591 ! '! : ! 1 5: 1. ! i! i,:: i '! 'I , *' i:' ! r: il ! i* ':' 592 CHAPTER 26 1954 Guide heating system exactly balanced to load conditions. To obtain the economies of mass production, factory built units must be standardized in a few models per manufacturer. Each model covers a range of capac ities within the capacity of its fan to deliver air against the resistance of the unit and against the system resistance. For this reason, the unit performance will usually represent a compromise between actual load requirements and the rated capacity. Within the range of accuracy of most load calculations, this compromise is not objectionable. If the condensing unit and cooling and heating coil surfaces are care fully selected, and if proper consideration is given to reduction of piping losses, the performance of the combined system will compare favorably with field assembled apparatus. A system in which the air handling unit is separated from the condensing unit, is called a remote system, and the conditioning unit is designated as a remote unit. The economical capac ities of remote units usually range from 10 to 40 tons. For applications where load calculations are subject to considerable. variance, and where close control is not considered essential, further econo mies of factory assembly can be obtained by combining the air handling and condensing equipment in one unit. This effects another compromise between load calculations and equipment selection, since the capacity of the combined unit is then dependent on the predetermined balance between a particular coil and condensing unit. These combination units are called self-contained units and, under the aptly descriptive name store conditioners, find economical application in 3, 5, 1\, 10, and 15 ton refrigeration capacities. These capacities, or limited multiples thereof, meet the load requirements of the majority of small and medium sized commercial establishments. With some modifications, these units can also be adapted to light industrial work. To meet the requirements of individual comfort in small rooms and offices, where load calculations are subject to the indefinite design con dition of feeling cool, self-contained units, called room coolers, find exten sive and economical application. These units are usually restricted to summer and intermediate season operation, and range from J to 1? 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 secondary consideration. Because of the small temperature differences between the coil and room temperatures, unit coolers handle three to five times as much air per ton as remote units used in air con ditioning. The attic fan or exhaust fan is sometimes referred to as a cooling unit, hut since it contains no element of heat transfer, it is treated in Chapter 33. Fans. COMPONENT PARTS OF UNIT TYPE EQUIPMENT Units can be obtained for producing any of the required effects on air. As they function most satisfactorily when doing the work for which they were designed, field modifications are-usually inadvisable because of expense involved, as well as the possibility of causing unexpected diffi culties in operation. The basic design considerations of unitary equip ment are discussed in the next following paragraphs. Unit Air Conditioners and Unit Air Coolers 593 Remote Units. Remote units can be obtained in two general classes, horizontal as shown in Fig. 1 and vertical as in Fig. 2, Their construction 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 air tight. Panels should be tight fitting with cam 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. Non-metallic 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 absorbing 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 otherwise treated to resist corrosion. Some manu facturers 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 accessible for cleaning and, in air conditioning work, should be generously sized and trapped. Some municipal codes require a minimum size of ljj I.P.S. Blowers. The usual practice among manufacturers is to use light con struction in the blowers in remote units, although a few are available with heavy duty blowers in the larger sizes. These blowers work under almost constant conditions without overload or shock, and will usually last as long as the unit with reasonable maintenance. As lubrication of bearings is very important, it is good practice to locate the oil cups conveniently out side of the unit. In any application where considerable dehumidification or humidification is involved, such as in a system where the unit is handling 100 percent outside air, it is important that the blowers be painted with asphaltum or other corrosion resistant paint to prevent excessive oxidation and corrosion of the blowers. Some of the smaller suspended type units, Fig. 3, use propeller fans with a trailing edge, blade in order to obtain required pressure character istics with quiet operation. Since most of the motors driving these fans are direct-connected and use brushes for starting, adequate access should be provided for maintenance 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 The face area of the coil is usually fixed, and the number of rows deep in the direction of air flow is the variable that determines capacity. It should be remembered that adequate coil surface is important for efficient Performance of any system, and that there is little economy in reducing coil depth to less than four rows. 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 hnl capacity of the coil. The cooling coils also perform the function of -humidification. To prevent carryover of condensate, eliminator plates Unit Air Conditioners and Unit Air Coolers 595 594 CHAPTER 26 1954 Guide should be used if face velocities exceed 500 to 530 fpm, unless adequate means of catching the droplets are provided. When air is drawn upward through dehumidifying coils, as in some vertical units, water is entrained within the fins and held in suspension. This increases the resistance pressure against which the blower operates, and results in wide variation in air volumes handled between dry and wet coil conditions. Some unit manufacturers have so designed vertical units that the air passes through the coils horizontally in order to overcome this difficulty. Healing Coils. Heating coils of unit air conditioners are usually conven tional 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 total number of rows of 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 adequate insulation. Spray type humidifiers should be located so that no carryover of moisture occurs. Fillers. 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 only with lint screens or operate without filters, but in them the coils must be periodically cleaned and there is con stant 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 in sure 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 heat load to be absorbed by the system, and this requires a lower exit air temperature at the coils. Usually, however, the motor is located outside 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 adequate horse power 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. SOUND ISOLATION Both suspended and vertical floor mounted units can transmit vibra tion through the supports. Wherever such transmission of sound might be objectionable, the supports should be isolated through rubber-in-shear r other sound deadeners. (For design of suitable sound deadeners see section Controlling Vibration from Machine Mountings in Chapter 41.) 596 CHAPTER 26 1954 Guide MODIFICATIONS OF REMOTE UNITS Features of various modifications of remote air conditioners are given in tiie following paragraphs. - Spray 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 mixing of the condensate 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 spray type units, absorbent brine solutions such as lithium chloride are used to remove moisture from the air. As explained in Chapter 38, 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. Factory produced units are also available for use with solid adsorbents such as silica gel. Remote Room Units For individual rooms, with cooling load requirements of 5 to 1J tons, remote units are available in attractive casings for installation within the room. A suspended type is shown in Fig. 3 and a floor type, such as is 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 existing offices, hotel, and apartment rooms. These units may be obtained with filters and outside air con nections, but for most satisfactory application are used as supplements to central systems that supply properly conditioned and filtered air to the areas served. Induction type units, using primary conditioned air under pressure to Induce local circulation, are described in Chapter 30. Self-Contained Units A typical large self-contained unit is shown in Fig. 6. It is essentially a remote vertical'type conditioner mounted on top of a sound insulated enclosure containing 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 dis charge, and safing the top of the unit. The heat generated by the compression of refrigerant gases and that given off by the electric motor are removed from the compressor compart ment in four ways: by the use of a water coil in the compressor compart ment ; by utilizing the cold suction gases; by drawing part of the return air through the compressor compartment, and finally by circulating room air through the compressor compartment by means of a fan. attached to the motor shaft. The 7J, 10, and 15 ton self-contained units usually have horizontal type conditioners. The condensing unit enclosures are not completely sound insulated, since they are not usually installed in the conditioned area. Most units can be divided into two or three sections for ease of Unit Air Conditioners and Unit Air Coolers 597 handling and installation. Although most large self-contained units have water-cooled condensers, the 7J, 10, and 15 ton units can be obtained for operation with evaporative condensers. Self-Contained Room Cooling Units Small self-contained units can be obtained with water-cooled conden sers, but they are generally air cooled. The air-cooled types are small in capacity, ranging from ^ to 1^ hp. Their principal application is for conditioning such spaces as hotel rooms, offices and residential living quarters. A duct connection between the unit and an outside window or ventilated air shaft is required to permit Fig. 6. Self-Contained Water-Cooled Air Conditioner Fig. 7. Self-Contained Air-Cooled Unit Air Conditioner disposal of the heat extracted from the conditioned area. The unit may stand in front of the window or be mounted on the window sill. Various styles and types of windows encountered tend to increase the difficulty of making the window connections. The evaporation of condensate on the condenser coils, as a means of disposing of moisture, will tend to increase the condensing capacity and reduce the operating head pressure. Some units add supplementary water so that increased capacity may' be obtained from constantly wetted condenser coil surface. Connections to an electrical outlet may be made through a conventional cord and plug or a Permanent electrical connection, depending on local code rulings per fuming to the installation of small motors, The exterior finish of the unit m metal, wood or fabric is decorated to harmonize with office or bedroom furnishings. A unit of the air-cooled condenser type for floor mounting is shown in mg- 7, Of the two fans shown, the lower one acts as condenser air fan, and in some units this fan is arranged with slingers for discharging con densate on the condenser coil, while the upper fan discharges air into the conditioned area. A feature of the design shown in Fig. 7 is that the 598 CHAPTER 26 1954 Guide condensate from the cooling coil is sprayed over the condenser surface and vaporized, thus eliminating the need for drain connections. A simple dampering arrangement is generally provided for exhausting some air from the room, in addition to introducing outside air and recirculating required amounts of air. It is possible to remove the equipment for winter storage or utilize the ventilating features for winter operation. Controls for Room Cooling Units Control devices provided for self-contained cooling units generally will include all necessary means for automatic operation. Provision is also made for adding auxiliary external controls, when desired. Remote units are not generally equipped with controls. Control systems for remote units, and auxiliary controls for self-contained units, are covered in the general treatment of Controls in Chapter 39. RATINGS OF UNIT AIR CONDITIONERS Two standards have been used for rating and testing of unit air con ditioners: (1) Standard Method of Rating and Testing Air Conditioning Equipment,1 covering all types of air conditioning units except the selfcontained type and (2) Standard Method of Rating and Testing SelfContained Air Conditioning Units for Comfort Cooling2 covering the selfcontained type. (ASRE Standard Methods of Rating and Testing Air Conditioners, ASRE Standard 16-R, covers rating and testing of all types which operate non-frosting when cooling and dehumidifying at standard rating conditions.) The standard rating of a self-contained unit for the conditions specified in Table 1, includes all items which apply to the function of a unit as: (I) name of unit, (2) functions 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 cooling is expressed as 50 percent relative humidity (66.7 F wet-bulb) instead of 67 F wet-bulb temperature. In addition, the saturated suction refrigerant temperature for comfort cooling is specified at 40 F. This condition is omitted from Table 1 for self-contained units because it is immaterial in the rating of a unit that in cludes 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 compactness, 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 servicing and main tenance of the equipment. Adequate outside clearance at these panels is essential. Wherever there is danger of freezing of coils or clogging with dirt, sufficient clearance should be available for replacing them without removing 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 Unit Air Conditioners and Unit Air Coolers 599' 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. ' Fan speeds should be selected accurately for the system resistance. Variable pitch motor pulleys are often provided in a unit for minor field Table 1. Standabb Rating Basis for Self-Contained Air Conditioning Units Function's Alt Cooling Types op Units Item Rating Condition Description | Value All a Barometric Pressure 29.92 in. Hg. Water-Cooled, Air - Cooled and Eva poratively Cooled Con densers b c Unit Ambient and Air Entering Room--Air Inlet (1) Dry-Bulb (2) Wet-Bulb Ventilation Air 80 F 67 F See Note Water-Cooled d Water Temperature Entering Condensers Unit 75 F e Air - Cooled and EvaporCooled Con* densers f Water Temperature Leaving Unit Air Entering Outside Air Inlet (1) Dry-Bulb . (2) Wet-Bulb 95 F 95 F 75 F Heating Humidifying Air Circula tion g All Types Pro vided with Heating Function h Unit Ambient and Total Air Entering Unit Heating Medium, Pressure or Temperature (1) Dry Saturated Steam (2) Water In (3) Water Out All Types Provided with Hu midifying Function i Unit Ambient j Total Air Entering Unit 1) Dry-Bulb ' [2) Wet-Bulb All k Filters 70 F 16.7 lb per sq in. abs 180 F 160 F 70 F 70 F 53 F New and Clean 87 ahaU,be ba3?Aan,l?oth ventilation and recirculated room air entering at 80 F dry-bulb and not pertinent to tldaehapder/^^0 ^ ^ glveu m code has been condensed in order to remove material adjustment of air volume. Any such field adjustment should be made when niters are dirty, to simulate average operating conditions. Because varying sizes of coils are used within the same casing, it is very important that coil safing be carefully installed to prevent by-passing j l^eonditioned air. If coils are not equipped with individual casings, additional safing may be required on top to prevent short circuiting air down through the upper edges of the fins. In this same category is ne need for careful installation of the various sections of sectionalized 600 CHAPTER 26 1954 Guide units, using a sealing compound if necessary to prevent air leakage into the fan section of the unit. . Since the drain connection is usually made on the exit side of the coil, it is important that the drain line be properly sealed. This sea! should be at least twice as deep as the suction on the fan in inches of water, to prevent gurgling sounds, and to insure a positive seal against infiltration of odors and moisture laden air. Drain pans should not be used to sup port the coils, unless they are designed to hold this weight without sagging. As the movement of air draws the condensate or excess humidification water toward the fan, drain connections are usually placed on the exit side of the coil. The advantages of quick drainage are lost if improperly supported coils distort drain pans and cause water to accumulate in the center or back of the pan. When the fans of vertical units are stopped, condensate that has been held up in the coils by fan suction, drops into the drain pan and splashes against the casing. If water damage is to be avoided, flashings should be provided to prevent this water from running out of the unit at the seams. 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 fire-proofing. A small fire, normally of little consequence, may cause a rupture of a heavily loaded structure and permit the equip ment 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 basement is an inex pensive 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 adequately 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 separate electrical circuit of adequate capacity from the main panel is more than justified; it is a neces sary expense in the majority of installations. A water supply of adequate capacity and pressure is necessary 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 lb pressure, including 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 sink as required by most city codes. This prevents back pres sures on the city water system in the event of condenser failure. A check valve should also be installed in the water supply as a further precaution against contamination. When installing small remote or self-contained units with outside air connections in buildings more than 6 stories high, the effect of wintertime Unit Air Conditioners and Unit Air Coolers 601 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 distribution. It can also cause annoying whistling at door openings 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 installed in the outside air intakes with adequate locking devices. One further consideration when installing self-contained units in con ditioned areas is that any maintenance or repairs to be required in future years must be carried on in occupied space. UNIT AIR COOLERS Unit air coolers are intended principally for product cooling, but are often used for cooling spaces to low temperatures. They differ from normal air' conditioning units only in features required to produce lower temperatures. In using such units, relative humidity and dry-bulb temperatures should be considered as carefully as in comfort air conditioning systems. Where the product being cooled is sealed in containers impermeable to water vapor, relative humidity becomes a secondary consideration. In recent years the unit cooler has almost entirely supplanted the gravity type prime-surface and finned-tube coil. It provides more positive con trol of air and better air distribution, is more efficient in performance, re quires less space, and is less expensive. In the past, applications of unit ' coolers were often limited to cold storage warehouses and to retail and wholesale markets for meat, fruit, and vegetables. In such applications, control of relative humidity was considered unimportant because of the low storage temperature or the temporary nature of the storage. In most of these cases, experience had indicated that approximately correct relative humidities would be obtained if the temperature differential between the room and refrigerant were maintained within a desirable range. Unit coolers, however, can perform satisfactorily in installations requir ing accurate control of relative humidity, air motion, and dry-bulb temper ature, and thereby prevent excessive weight loss, mold and slime growth, and moisture absorption by hygroscopic materials such as dried fruits. Unit coolers, especially in the smaller sizes, are very similar in appear ance to unit heaters. Copper or steel prime or finned surface tubes are arranged in single or multiple circuits, depending on the loading. Pro peller or centrifugal fans either blow or draw room air over the tubes. The fan and coil are generally enclosed in a casing provided with a drip pan. The motor horsepower requirements are a function of the air quantity and coil depth, that is, the number of rows of tubes. Finned coils are generally four to six rows in depth while prime-surface coils range from six to ten rows in depth. Fin spacing is based principally on operating temperature and the ratio between latent and total load. For operation below 32 F, . hn spacing may vary from 2 to 6 fins per inch, while above 32 F it may vary from 5 t0 8 fins per inch. Both direct expansion refrigerants and bnne are used successfully as cooling mediums. Unit coolers may be arranged for either free or duct delivery. Face vel ocities vary from 200 to 800 fpm, depending principally upon the intended aPpfication of the unit. In the larger sizes particularly, speed adjustment of the fan is generally provided to permit variation of the air delivery, and Pus obtain a closer control of the relative humidity. While unit coolers are usually installed in the storage space, remote installation combined with 602 CHAPTER 26 1954 Guide appropriate duct work may be required by space or other considerations. Units are available for.floor, wall, or ceiling mounting,, thus providing an upward, downward, or horizontal discharge. Power, refrigerant, and drip pan connections are required, plus additional connections for defrosting, if necessary. Various methods of defrosting are used. In one method, hot gas is supplied to the interior of the tubes uniformly throughout the coil. The entire refrigerant circuit is thus contacted to obtain complete defrosting of all frosted surfaces. Electric defrosting generally involves the incor poration of heating elements 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 refrigera tion system and circulating the, room air over the coil. In every case, de frosting requires a cessation of refrigeration. and fan shut down. 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. Ratings As various means of expressing unit cooler capacity are utilized in the industry, different manufacturers suggest different 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 following paragraphs. The refrigerating capacity of the unit may be either gross or net, the latter being less 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. 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 pres sure drop increases as the evaporating temperature decreases, and thus temperature level exercises a significant effect on the average coil surface temperature and the consequent condensing unit selection. Coil capacity rating is usually expressed as simplified, rating or sensible heat ratio rating: the latter derives its name from the ratio of the sensible heat load to the total load. The simplified rating expresses the capacity in terms of Btu per (hour) (Fahrenheit degree temperature differential between the refrigerant and the air). The sensible heat ratio rating expresses the unit cooler capacity in terms of Btu per (hour) (Fahrenheit degree temperature differential between the refrigerant and the coil surface tempera ture). The simplified rating method does not require knowledge of the sensible heat ratio. When the total load has been obtained from the load calculations, it is necessary only to assume a temperature differential be tween the air and the refrigerant in order to select a unit cooler. Sinoe the extent of dehumidification will be a function of this assumed tempera ture differential, it is apparent that the relative humidity in the storage space is dependent upon the correct assumption of this temperature differ ential. For many applications, the correct temperature differential has been established between certain maximum and minimum values. In such applications, the simplified rating offers a quick method of selection. Where past experience is lacking, and in any case where close control of relative humidity is desired, the simplified rating may be used for tentative Unit Air Conditioners and Unit Air Coolers 603 selection of the unit, but the sensible heat ratio method should be used in the final selection. . .. In the sensible heat ratio selection method, the total heat is used in con junction with the air distribution requirements for making a tentative selection of a unit cooler. Then, for the specific air volume and surface area of the unit cooler selected, it is necessary to determine the refrigerant temperature required to maintain the dry-bulb temperature and relative humidity desired in the storage space. In order to apply air conditioning psychrometric techniques for accurate control of the room conditions a knowledge of the sensible and latent loads is required. The relationship of these loads is evident in the term, sensible heat'ratio. . From this ratio and the unit cooler air volume, the supply air conditions to maintain the storage room design conditions may be calculated. . The extent to which these supply air conditions differ from the average coil surface temperature is a function of the fin spacing, fin style, coil depth, and other factors inherent in the design of the coil. From a knowledge of the efficiency of his specific coils, a manufacturer can use the sensible, heat ratio to determine the average coil surface temperature necessary to main tain desired storage room conditions, without actually evaluating the supply air conditions. -__ , For a unit cooler adjusted to deliver a specific air volume, there exists . a specific differential between the storage room conditions and the average coil surface temperature, and, therefore, it is possible to rate coolers on the basis of this room-to-surfaee temperature differential. Refrigerant side pressure drop and the characteristics' of the heat trans fer surface, introduce a differential between the average coil surface tem perature and the refrigerant temperature. Thus, the manufacturer must also present data from which the engineer can determine the overall roomto-refrigerant temperature differential necessary with the unit cooler se lected. Some-manufacturers rate cooling equipment on the basis of the overall room-to-refrigerant temperature differential instead of using the in termediate average coil surface temperature. In either case the signifi cant consideration is, that this overall temperature differential must be determined from a knowledge of the sensible heat ratio and the air volume of a unit cooler under consideration. If the tentatively selected unit cooler does not possess the proper capacity, it may often be possible to ad just the fan speed to a new air volume. At the new air volume and new overall differential, the cooler may be able to deliver the necessary cooling capacity. If not, the procedure must be repeated with another size of unit cooler, the final selection being based on the economical balance be tween unit cooler, the compressor, and the condenser. Procedures for rating and testing room coolers are given in an ASRE Standard3 which establishes four groups of conditions (numbered I to IV) under which units may be rated. Many manufacturers establish and pub lish their ratings in accordance with this standard. In this standard, forced circulation air coolers are classified according to air side surface conditions as (1) dry coil, (2) sprayed coil, and (3) spray-- uo coil; or according to type of air delivery to room as (1) free delivery fan, r (2) pressure fan. Natural convection air coolers are classified according 10 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 thermo static expansion valve, thus obtaining dry expansion in the evaporator. 604 CHAPTER 26 1954 Guide Many prime surface coils utilize flooded expansion as obtained with a float valve to improve the heat transfer coefficient. Where dry'expansion is used, many coil manufacturers recommend the use of a liquid-vapor heat exchanger to increase the coil efficiency by obtaining the control of super heat in the heat exchanger rather than in the evaporator coil. Liquid subcooling thus obtained contributes to an increase in the overall efficiency of the refrigeration system. Where two or more evaporator coils are to be attached to a single con densing unit, and different evaporator temperatures are desired, a back pressure valve may be installed to limit the minimum evaporating tempera ture of the warmer coils. This valve also finds application where fluctua tion in the evaporator temperature prevents accurate control of air tem perature and humidity. ' The importance of securing uniform air distribution to every part of the product zone, and the use of a permissible velocity of air over the product, must be recognized when selecting the unit coolers and their outlets. For each product there are certain maximum and minimum permissible velo cities. If the average velocity falls below the maximum allowable velo city, it is of no consequence so long as the air distribution throughout the storage space is uniform and every portion of the room is reached by cooled air. It is important to note that the quantity of air in motion in the re frigerated 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 location of the unit relative to restrictive walls and prod uct. . Unit location is also important from the standpoint of occupant com fort, low velocity outlets being preferred for floor type units. High velo city 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 in a location such that 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. REFERENCES 1 Prepared by a Joint Committee of the American Society of Refrigerating. Engi neers, American Society op Heating and Ventilating Engineers, Refrigerating Machinery Association, National Electrical Manufacturers' Association, and Air Conditioning Manufacturers' Association (A.S.R.E. Circular No. 13-42).* 1 Standard Method of Rating and Testing Self-Contained Air Conditioning Units for Comfort Cooling prepared by a Joint Committee of the American Society of Re frigerating Engineers, American Society op Heating and Ventilating Engineers, Refrigerating Machinery Association, National Electrical Manufacturers' Association, and Air Conditioning Manufacturers' Association (A.S.R.E. Circular No. 16).* ' Proposed A.S.R.E. Standard Methods of Rating and Testing Forced-Circulation and Natural Convection Air Coolers for Refrigeration (A.S.R.E. Circular No. 25-44). * ASRE has combined Circulars No. 13-42 and No. 16 in ASRS Standard No. lfr-K, Methods Hating and Testing Air Conditioners. ' CHAPTER 27 PIPE, FITTINGS, WELDING Pipe Materials, Types of Pipe, Commercial Pipe Dimensions, Expansion and Flexibility of Pipe, Hangers and Supports, Threading Practice, Types of Fittings, Flange Facings and Gaskets, Welding in Erection .` of Piping, Valves IMPORTANT considerations in the selection and installation 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 brass, has increased considerably during the past few years. The development of copper, brass, and bronze fittings which can be assembled by soldering or sweating, permits the use of thin-wall pipe and thereby has reduced the initial cost of such installations. The follow ing 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 acidbessemer, the open-hearth, or the electric-furnace process. Ordinary wrought-steel pipe is made either by shaping sheets of metal into cylindri cal form and welding the edges together, or by forming or drawing from a solid billet. The former is known as welded pipe, the latter as seamless pipe. Many types of welded pipe are available, although the smaller sizes most frequently used in heating and ventilating work are made by the lap-weld, resistance-weld, or butt-weld process. While the lap-weld and resistance-weld processes produce a better weld than the butt type, lapweld and 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 pressure 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 op erations. Its advantages are its greater strength which permits use of a thinner wall and, in the small sizes, its freedom from the occasional tendency of welded pipe to split at the weld when bent. Wrought-Iran 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 disclose different grain structures. Cast-Ferrous Pipe. There are now available several types of cast-ferrous ' 605 . 606 CHAPTER 27 1954 Guide Table 1. Dimensions and Properties of SteelJPipe Pipe, Fittings, Welding 607 (Concluded)Table 1. Dimensions and Properties of Steel Pipe Nom inal1 Size ASTM* SCHE- Diameter O. D. I. D. In. In. la Surface Area Sq Ft/LiN Ft 3S. < S5 S O. D. I. D. Section Area Sq In. O. D. I. D. Area of Sq In Vol ume Lin JFt Weight* (plain end) Lbs/Lin Ft Working Pres sure* PSIA 20 20 (s) 20.000 19.250 0.375 5.23 4.51 314. 291. 23.2 15.2 78.6 : 319 (c) 30 (s) 20.000 19.000 0.500 5.23 4.97 314. 284. 30.6 14.7 104.2 454 (c) 24 20 24.000 23.250 0.375 6.29 6:08 ' 452. 426: 26.8'1 ; 22.1 94:6 (8) 24.000 23.000 0.500 6.29 , 6.03 452. . 415. 36.9.. . 21,5 125.5 265 (c) 378 (c) * 3H Double extra strong is no longer considered in ASTM specification but some pipe of t.hi size is still manufactured. > . . 1 The sizes for wrought iron are approximately the same except wall thickness is-slightly heavier. See * American Society for Testing Materials Schedule. The numbers 30,40, etc., refer to the ASTM Schedule; the letter (s) refers to the former designation Standard Weighi; the letter (x) refers to the former designation Extra Strong; the letters XX refer to the former designation Dovble Extra Strong.. - . 1 Weight per foot is based on plain end pipe. Threaded and coupled (-T and C) pipe is slightly heavier. 4 Working pressure for welded joints--see formula in Table 3. . (a) Working pressure based on an allowable fiber stress of 6225 psi (for 250 F). (b). Working pressure based on an allowable fiber stress of 8400 psi (for 250 F). (c) Working pressure based on an allowable fiber stress of 12000 psi (for 250 F). ' . Note: Standard-weight pipe is generally furnished with threaded ends in random lengths of 16 to 22 ft., although when ordered with plain ends, 5 percent may be in lengths of 12 to 16 ft. Five percent of the total cumber of lengths ordered may be jointers which are two pieces coupled together. Extra-strong pipe is generally furnished with plain ends in random lengths of 12 to 22 ft., although 5 percent may be in lengths of 6 to 12 ft. ' metal pipe made of a good grade of cast-iron with or without additions of nickel, chromium, or other alloy. This pipe is available in sizes from 1^2 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. Castferrous pipe may be obtained coupled, beveled for welding, or with ends plain or grooved for the several types of couplings. It is easily 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 classIn the case of iron pipe when copper and molybdenum are added, the ma terial is known as alloy wrought-iron. 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 man ganese, 0.60 silicon, or 0.60 copper. Also, a steel is an alloy if any of the following elements are specified in minimal quantities or within limits: AI, 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--0.20 percent, and molybdenum--0.06 percent. Commercially, steel is considered stainless when chromium exceeds 3.99 percent regardless of the inclusion of other alloying elements. With iub- however, an alloy becomes stainless when it contains a minimum of 10-5 percent chromium. The alloy and stainless steels are used for high temperature piping and for highly corrosive fluids and gases. Copper Pipe and Fittings. Owing to inherent resistance to corrosion, Pipe, Fittings, Welding 609 1954 Guide * CHAPTER 27 608 copper and brass pipe have always been used in heating, ventilating, and water supply installations, but the cost with standard- dimensions for Copper Tube threaded connections has been high. The introduction of fittings which permit erection by soldering or sweating, allows theuse of pipe with thinner walls than would be possible with threaded connections, 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--ASTM 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 Table 3. Table op Availability fob Steel Pipe Material . Specification Available Sizes (Inclusive) Inches Diam. Allowable Fiber Stress S* psi Butt-weld 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 H to 4 H to 4 2 to 12 2 to 24' 2 to 24 2 to 24 2 to 24 2 to 24 2 to 12 6,225 6,750 . 8,400 9,000 10,200" ; 12,750" 12,000 15,000 10,460 " For use in the equation p r= (fm --c) D -6.8 (im --c) See American Standard Code for Pressure Piping, pub lished by ASME, revised November, 1952. Where P = working pressure, pounds per square inch. 8 = fiberatress, pounds per equate inch. = 0.875 x wall thickness, inches. - D * O. D., inches. c ** joint factor = 0.05 for 1-in. and smaller size or 0.065 for larger than 1-in. size. . b tor electric resistance welded pipe for applications where the temperature.is below 650 F, and where PlPe furnished under this classification is subjected to supplemental tests and/or heat treatments as agreed to by the supplier and the purchaser, and whereby such supplemental teats and/or heat treatments demon* atoate the strength characteristics of the weld to be equal to the minimum tensile strength specified for the Pipe, the 5 values equal to the corresponding seamless grades may be used. j M |is!.'i5|n.617| 0.254 ( 3.W | o., , Working pressure is based on theAmerican Standard Code for Pressure Piping, published by the ASUS, Weight per foot is based on tubing without couplings. rifled Novepmbaer, 1952 ior plain end tuwbhienrge P(sw~eatlljoowinatbsl)e. pressure, pounds per square inch. D --Q.8tm * ~ 5125 psi allowable fiber stress, pounds per square inch* ttn ~ minimum wall thickness, inches. Since copper tubing wilt be subject toDa c=ermtaainxiammuomunOt.oDf a.,ninechaelins.g when heated joints are m*d,e' 0 TfyibpeerssKtresasndisLbafsuerndisohneadnnineableodthtubbairndgaantd2s5o0 fFt .tempers. Type M in hard only. laughs are 12 and 20 ft. Standard coils (}< to lii inch) are 60 ft. standards for copper or brass IPS, clay or concrete, and cast-iron pipe. Copies of the following specifications may be obtained from the American society for Testing Materials: (1) steel, wrought-iron and cast-iron--Series (2) copper and brass--Series B, and (3) clay and concrete--Series C. Table 3 lists the sizes available in each of the specifications and classes th s^e* PiPe- Note that butt-weld is not available above 4-in. size and hat lap-weld, electric-resistance-weld, and seamless are not available be low 2-in. size. i lfted 'n ^ is the formula for allowable working pressures as given o the American Standard Code for Pressure Piping. In this formula is a actor c, which is intended as an allowance for corrosion, mechanical in i r^' manufacturing tolerances, etc. At times this factor seems too con- 'vatjvg. for example, with Schedule 40, steel pipe, the allowable riQng pressure is 314 psi. Yet this pipe is tested at 700 psi. The reason- 610 CHAPTER 27 1954 Guide mg 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. Dimen sions of copper water tubing intended for plumbing, underground water service, fuel-oil lines, gas lines', etc., have been standardized by the TJ. S. Government and the American Society for Testing Materials. There are three standard wall-thickness schedules of copper water tubing classified in accordance with their principal uses as follows: Type K--Designed for underground services' and general plumbing service. Type L--Designed for general plumbing purposes. '' Tvne M--Designed for use with soldered fittings only. Table 4. Thermal Expansion op Pipe in Inches per 100 n* ' {For superheated steam and other fluid* refer to temperature column) Saturated Steam ELONGATION IN INCHES PBB 100 PT-FBOM --20 F UP Saturated Steam 1 Elongation in Inches pee , Vacu um Inches Pres sure Psig Temper ature i Cast- Fahren Iron heit Pipe [Wrought- Steel- Iron Pipe Pipe Copper Pipe Pres sure Psig Temper ature Fahren heit Degrees Cast-] Wrought- Iron Steel Pipe Pipe iron Pipe per -20 0 0 ; 0 0 220of Hg Degrees : 2.5 17634 1.852 1.936 "2.720 200 0.29.39 28.89 10027.99 12026.48 24.04 1.200!20.27 14.63 2006.45 From Piping 0.127 0.145] 0.152 0.204' 10.3 0.255] 0.293 .0.306 0.442] > 20.7 40 0.390 0.430] 0.465 0.655] 34.5 60 80 0.518' 0.593 0.620 0.649 0.725) 0.780 0.7871 0.898' . 0.939 l.ioo] 1.338 52.3 . 74.9 103.3 0.92o| 1.055 1.110 1.570 138.3 140 160 180 1.051 1.209! 1.368 1.345] 1.528] 1.265 1.427 1.597. 1.794 2.008 2.255] 180.9 232.4 293.7 1.495 1.691 .1.778 2.500 366.1 Handbook, by Walker and Crocker. This table 240 300 320 it 340 360 380 400 420 . 440 gives the 1.780 2.020 1.931 2.183 2.085 2.350 2.233 2.519 2.395 2.690 2.543 ,2.862 2.700 3.029 2.859 3.211 3.008 3.375 3.182 . 3.56( 13.345 3.74( 2.110 2.279 2.465 2.630 2.800 2.988 3.175 3.350 3.251 3.720 3.900 2.960i 3.189 3.422 3.665 3.900. 4.145 4.380 4.62S 4.870 5.118 _ 5.358 expansion from --20 F to the temperature in question. To obtain the amount of expansion between any two temperatures take the; difference between the figures in the table for those temperatures. -For example, if a steel pipe is installed at a temperature of 60 F and is to operate at 300 F, the expansion would be 2.519 -- 0.593 -- 1.926 in/ ' In general, Type K is used where corrosion conditions are severe, and Types L and M where such conditions may. be. considered normal as, for instance, in heating work. Types K.and L are available in both hard and soft tempers; Type M is available only in hard temper. Where flexibility inessential as in hidden replacement work, or where as few joints as posable are desired as iii fuel-oil lines, the soft temper is commonly used. In new or exposed work copper pipe of a hard temper is generally used. All three claSsstaesndaarerdexdtiemnesnivseiolynsu,sewdewigihthts,soalndedreddiafmitteintegrs.and wall-thickness toler ances for these classes of copper tubing.are obtainable from Table 2. Cop peTr npirpeefriigsearlastoioanvlairiileasb,leuswedithindciomnennesciotinosn owfitshteaeilrpciopne.ditioning equipment> Pipe, Fittings, Welding 611 copper tube is used extensively. For refrigeration use where tubing abso lutely free from scale and dirt is required, bright annealed copper tubing that has been deoxidized is used. This tubing is available in a variety of sizes and wall thicknesses. ' . : EXPANSION AND FLEXIBILITY The increase in temperature of a pipe from room temperature to an oper ating steam or water temperature TOO deg or more above , room tempera ture, results in an increase in, length of the pipe for which provision must be made. The amount of linear expansion (or contraction in the case of refrigeration lines) per unit length of material per degree change in tem perature is termed the coefficient of linear expansion, or commonly, the coefficient of expansion. This coefficient varies with the material. The linear, expansion of cast-iron,, steel, wrought-iron, and copper pipe, the materials most frequently used in heating and ventilating work, can be determined from Table 4. , ... . The three methods by which the elongation due to thermal expansion may be taken care of are: (1) expansion joints; (2) swivel joints; (3) in herent flexibility of the pipe itself utilized through pipe bends, right-angle turns, or offsets in theTine. Expansion joints of the slip-sleeve, diaphragm, or corrugated types made of copper, rubber, or other gasket material are all used for taking up ex pansion, but generally only for'low pressures or where the inherent flexi bility of the pipe cannot readily be used as in underground steam or hot water distribution lines. Swivel joints are used to some extent in low-pressure steam and hot- water heating systems, and in hot-water supply lines. Since swivel joints permit the expansive movement of the pipe by turning of threaded joints, which may ultimately result in a leak, it is preferable to provide sufficient flexibility without resorting to swiveling in the threads. Probably the most economical method of providing for expansion of piping in a long run is to take advantage of the directional changes which must necessarily occur in the piping, and proportion the offsets so that sufficient flexibility is secured. Ninety-degree bends with long, straight tangents in either a horizontal or a vertical plane are an excellent means for securing adequate flexibility with larger sizes of pipe. When flexi bility cannot be obtained in this manner, it is necessary to make use of some type of expansion bend. The exact calculation of the size of ex pansion bends required to take up a given amount of thermal expansion js relatively complicated.1 The following approximate method, however, oas been found to give reasonably good results and is deemed to be suf ficiently accurate for most heating installations. Pig. 1 shows several types of expansion bends commonly used for taking ?P thermal expansion. The amount of pipe, L, required in each of these bends may be computed from Equation 1. u>bere L = 6.16 VDa (1) b = length of pipe, feet. - outside diameter of the pipe used, inches. ^ = the amount of expansion to be taken up, inches. ^fiis formula, based on the use of mild-steel pipe with wall thicknesses i 612 CHAPTER 27 .. 1954 Guide not heavier than extra-strong, assumes a maximum safe value of fiber stress of 16,000 psi. When square type bends are used, the width B of the bend should not. exceed about twice the height, since for a given total length of pipe in the bend, the height A of the bend becomes progressively less with increase in width until the height approaches zero and no flexi bility exists. Actually, wide bends utilize to best advantage the inherent flexibility of the line, but such bends cannot be proportioned on the basis of Equation 1. For such applications, more' accurate' methods1 should be employed. It is further assumed that the comers are made with screwed or flanged elbows or with arcs of circles having radii five to six times the pipe diameter. Use of welding elbows with radii of 1^ times the pipe diameter will decrease the end thrusts somewhat,- but will raise the fiber stress correspondingly. -' . All risers must be anchored and safeguarded so that the difference in' length when hot, from the length when cold, shall not disarrange the normal and orderly provisions for drainage of the branches. ' Proper anchoring of piping is especially necessary with light-weight radiators, to allow for freedom of expansion in order that no pipe strain Offset U bend Fig. 1. Measurement op L on Various Pipe Bends will distort the radiators. When expansion strains from the pipes are permitted to reach these light metal heaters, they usually emit disturbing sounds. . HANGERS AND SUPPORTS Heating system piping requires careful and substantial support. Where changes in temperature of the line are not large, such simple methods of support may be utilized as hanging the line by means of rods or perforated strip from the building structure, or supporting it by brackets or on piers: When fluids are conveyed at temperatures of 150 F or above, however,, hangers or supporting equipment must be fabricated and assembled h>' permit free expansion or contraction of the piping. This can be accom plished by the use of long rod hangers, spring hangers, chains, hangers or supports fitted with rollers, machined blocks, elliptical or circular rings of larger diameter than the pipe giving contact only at the bottom, or trolley hangers. In all cases, allowance should be made for rod clearance to permit swinging without setting up severe bending action in the rods. ' For pipes of small size, perforated metal strip is often used. For hori zontal mains, the rod or strip usually is attached to the joists or steel wort of the floor above. For long runs of vertical pipe subject to considerable thermal expansion, either the hangers should be designed to prevent ex- Pipe, Fittings, Welding 613 cessive load on the bottom support due to expansion, or the bottom support: should be designed to withstand the entire load. . THREADING PRACTICE In all threaded pipe for heating and ventilating installations the American Standard taper pipe thread, ASA B2.1-1942 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 order ing line pipe2 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 the 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 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 5 contains pertinent threading data for standard weight, extra strong and double extra strong steel, and wrought-iron pipe. TYPES OF FITTINGS Fittings for joining the separate lengths of pipe together are made in a variety of forms, and are either screwed or flanged, the former being generally used for the smaller sizes of pipe up to and including %Y in-, and the latter for the larger sizes, 4 in. and above. Screwed fittings of large size, as well as flanged fittings of small size, are also made and are used for certain classes of work at the proper pressure. The material used for fittings is generally cast-iron, but in addition to this, malleable-iron, steel and steel alloys are also used, as well as various grades of brass or bronze. The material to be used depends on the char acter of the service and the pressure. Malleable iron fittings, like brass fittings, are cast with a round instead of a flat band or bead, or with no bead at all. Fittings are designated as male or female, depending on whether the threads are on the outside or inside, respectively. Screwed galvanized fittings are made according to the 150 lb American Standard. As in the case of pipe, several weights of fittings are manufactured, recognized American Standards for the various weights are as follows: P'P flanges and flanged fittings for 25 lb (sizes 4 in. and larger), 125 lb, sPWtirc| maximum aaturated steam pressure, ASA B16b2, B16a, and B16b, re- 4g^ajjable iron screwed fittings for 150 lb maximum saturated steam pressure. ^g-j^tjbon screwed fittings for 125 and 250 lb maximum saturated steam pressure an6e<l fittings for 150 and 300 lb maximum steam service pressure,.ASA fn allowable cold water working pressures for these standards vary from 43 lb the 25 lb standard, to 500 lb for the 300 lb steel standard. `614 CHAPTER 27 1954 GuideSf m War standard ratings in! effect for-the duration of the emergency per4 mitted higher ratings for certain sizes of the 125 lb cast-iron flanged^ fitting standard, and for 300 lb steel flanges and flanged fittings, thanithose shown in the regular American Standards mentioned previously. ' Screwed fittings, include; .nipples or short pieces of pipe of varying;, lengths; couplings of steel or. wrought-iron; elbows for. turning angles of either 45 deg or 90 deg; return bends, which may be of either the close or open pattern, and.may be:cast with either a back or, side outlet; tees; Table 5. Threading Data for Pipe Nominal Size* , "H H ' H H N 1 iu ly* 2 6 12 16 20 Pipe O. D. -. Standard Weight Sxtra and Double Extra Strong, Threads, Coupling Coupling per Inch ... O. D.. Length Threads per Inch Coupling Coupling O. D. Length - 0.405 0.540 0.675. 0.840 : . 1.050 ' 27 0.563 18 0;719 18 i - 0.875 14 - . 1.063 14 ' . 1.313 ' ; 1M lfte .m 27 18 1 18 14 14 0.563 0.719 0.875 1.063 1.313 lHo . 1H m 1.315 1.660 1.990 2.375 2.875 HM 11H 11*4 mV 8 1.576 1.900 2.200 2.750 3.250 2 ' 2Me . 2M 2M 3H im im 11*4 8 1.576 2.054 2.200 2.875 3.375 2M 2?i 2?4 4H 3.500 4.000 4.500 5.563 6.625/ -8; 8 ! -8 . -8 . ' ' 8 : > ' 4.000 4.625 5.000 6.296 7.390 3U 8 3H 8 3H . 8 3H 8 48 4.000 4.625 5-200 6.296 7.390 w 4H 4*4 4n 8.625 10.750 12.750 14.000 : 16.000 18.000 20.000 __i __ - 8 . ; . -- . . - , -- ' , 8 .-- , 8 8 V 8 9.625 11.750 . 14.000 15-000 17.000 / _ . ' __ ' . -- '' .. __ -- 8 / 8` 19.009 21.000 SH 6*6 6H 654 7>6 7*6 * All dimensions in inches.' : > b Taper of threads is H in., per ft on diameter on all sizes of pipe, and m . couplings of 2^ in. and over. Couplings 2 in. and smaller are straight tapped. crosses; laterals or Y branches; and a variety of plugs, bushings, caps,, lock-nuts, flanges and reducing fittings. Reducing fittings as well as bushings, both of which are used in changing from one pipe size to another, may have the smaller connection tapped eccentrically to permit free drain age of the water of condensation in steam fines or free escape of- air in water fines. Fittings for copper tubing are available in the soldered, flared, or com pression types. Illustrations of each of these types are shown in Fig- 2Fittings for copper pipe of IPS dimensions are available in screwed oi soldered types of connection. Table 6 from ASA Standard A40.3-1941 contains dimensions for soldered joint elbows, tees, crosses, and 45 deg elbows. . The compression type fitting is generally limited to smaller size tubing) Pipe, Fittings, Welding 615 while the flared and soldered types are used in both large and small sizes,. An American Standard, 4<SA A40.2-1936 has been prepared to stand ardize dimensions for brass fittings for flared copper water tubes. Flared tube fittings are widely used in refrigerating work where S.A.E. dimensions and a 45-deg flare render, most fittings interchangeable, although for re ' frigeration use, thread fits:and tolerances on thread gages must be main tained within close limits. Brass fittings with S.A.E. dimensions are not interchangeable with the American Standard fittings for water tubes. Ammonia pipe fittings, made of cast-iron were formerly used extensively in handling refrigerants in large installations. Replacement of ammonia by other refrigerants operating at lower pressures has seriously curtailed solder-typc fitting FlARLD-TUBPIG FITTINGS Fig. 2. Copper or Brass Tubing Fittings tne market for these fittings. For this reason formulation of an American Standard for these fittings was abandoned by the ASA in 1936. ' FLANGE FACINGS AND GASKETS A number of different flange facings in common use are plain face, raised face, tongue and groove, and male and female. Cast-iron fittings for 125 Psi and below are normally furnished with a plain face, while the 250 lb cast-iron fittings are supplied with a -jV-in. raised face. The standard facing for steel flanged fittings for 150 and 300 psi is a iVin. raised face, although these fittings are obtainable with a variety of facings. The gasket surface of the raised face may be finished smooth or may be machined 'vith concentric or spiral grooves often referred to as serrated face or phonograph finish, respectively. The dimensions of elbows, tees, and crosses for 125 lb cast-iron screwed fittings are given in Table 7, whereas the dimensions for 125 lb cast-iron flanged fittings are given in Table 8. . Tor low temperature service not to exceed about 220 F, a number of. 616 CHAPTER 27 1954 Guide naper or vegetable fiber gasket materials will prove satisfactory; for plain raised face flanges, rubber or rubber inserted gaskets are' commonly em- Asbestos composition gaskets are probably the most widely used, particularly where the temperature exceeds 250 F. Jacketed asbestos and metallic gaskets may be used for any pressure and temperature conditions, but preferably only with a narrow recessed facing. Table 6. American Standard Dimensions or Elbows, Tees, Crosses, and 45 ASA A40.3-1941A Deq Elbows, Solderbd-Joint Fittings, Pipe, Fittings, Weldin! 617 mended on the basis of a greatly reduced cost of maintenance and repair, of less weight resulting from the use of a lighter-weight pipe, and of increased economy in pipe insulation, hangers, and supports rather than on the basis of any economy that might be effected in actual erection by welding on low to medium pressure heating jobs. ' Table 7. American Standard Dimensions of Elbows, 45-Deo Elbows, Tees and Crosses (Straight Sizes) fob Class 125 Cast-Iron Screwed Fittings, ASA B16a-1939 All dimensions given in inches. a This ai*e is the nominal bore of the tube. _, b These dimensions may be used for wrought-metal fittings as well as for cast-brass fittings at man This dimension is the same as the inside diameter Class L tubing (American Standard Specifications for Copper Water Tube. ASA H23.1-1939 U.S.T.M. B88). * noint d patterns shall be designed to produce body thicknesses given in the table. Metal thickness at no BKoii be less than 90 percent of the thicknesses given in the table. This dimension has the same thicknesses as Type 1* tubing. I These dimensions are minimum, but in every case the thickness of wrought fittings should be as .u . heavy as the tubing with which it is to be used. /the bottom Note 1:--Wrought fittings, as well as cast fittings, must be provided with a shoulderor stop end of socket. # . ... . Note 2:--Street fittings with male ends are for use in connection with other fittings Ulustraseo. WELDING Erection of piping in heating and ventilating installations by mea*f an fusion welding has been commonly accepted in the past few^ years> alternate method to the screwed and flanged joint. Since the ,q cttjngs of economy of welding as against the use of screwed a,nd flange is dependent on the individual job, the use of welding is generally b: c [=Ksry 45 deg elbow Nominal Pips SlZB . A Center to End, Elbowb. Tees Cbosses c B B Center to End, 45 Dxo Elbows Length Width op Thread, op Band, Min. ' Min. f Inside Diameter op Fitting Min. Max. aB Metal Thicxness, Min. Outside Diameter op Band. Min. uH - 0.81 0.95 1.12 1.31 1 1.50 1.75 1.94 2.25 2.70 3.08 3.42 3.79 4.50 5.13 0.73 0.80 0.88 0.98 1.12 1.29 1*43 1.68 1.95 2.17 2.39 2.61 3.05 3.46 0.32 0.36 0.43 0.50 0.58 0.67 0.70 0.75 0.92 0.98 1.03 1.08 1.18 1.28 0.38 0.44 0.50 0.56 > 0.62 0.69 0.75 0.84 0.94 1.00 1.06 1.12 1.18 1.28 0.540 0.675 0.840 1.050 1.315 1.660 1.900 2.375 2.875 3.500 4.000 4.500 5.563 6.625 0.584 0.719 0.897 1.107 1.385 1.730 1.970 2.445 2.975 3.600 4.100 4.600 5.663 6.725 0.110 0.120 0.130 0.155 0.170 0.185 0.200 0.220 0.240 0.260 0.280 0.310` 0.380 0.430 0.93 1.12 1.34 1.63 1.95 2.39 2.68 3.28 3.86 4.62 5.20 5.79 7.05 8.28 12 8.08b 9.50b 4.28 5.16 5.97 1.47 1.68 1.88 1.47 8.625 8.725 0.550 1.68 10.750 10.850 0.690 1.88 12.750 12.850 0.800 10.63 13.12 15.47 AU dimensions given in inches. 1* designed to produce esstings of metal thickness given in the table. Metal thickness "O point shaU be less than 90 percent of the thickness given in the table. Applies to elbows and tees only. Drop " "c!TBi cummomy used in erection ol piping, is defined as the witluf^+t.^01n'n8 mptal parts, in the molten, or molten and vapor states, emhr U *"le aPP^c.atin of mechanical pressure or blows. Fusion welding used fCeS ga? we'ding and electric arc welding, both of which are commonly desnv t? . uce accePtable welds. Welding processes and procedure are "escribed in various publications. e ding application requires the same basic knowledge of design as do 618 CHAPTER 27 1954 Guide - Table 8. American Standard Dimensions of Tees, Crosses*' (Straight Sizes), 125 B16a-1939and Elbows for Class ASACast-Iron Flanged Fittings, Pipe, Fittings, Welding 619 the other types of assembly, but, ,in addition, requires a generous knowl edge of the sciences involved, particularly as to welding qualities of metal, their reaction to extremely high temperatures, and the ability to deter mine and use only the best quality welding rods, this requirement applies equally to employer and employee, with the employer accepting all of the 9.Table American Standard Dimensions for Butt-Welding Elbows, Tees, B16.9-1940Caps, and Lapped-Joint Stub Ends, ASA Nominal Pm Size1*-4 A Center to Face Tees, Crosses-** and Elbows AA ' B Face to Face Tbes AND Crosses0-*! Center to Face Long Radios . ELB0Wf,8 c Center to Face 45 Dso Elbows DuMETER or Flanob Tbicxness or Flange. Mm. MetaUi Thickness or Boot i Di 1)4 2 2)4 3 3)4 4 5 6 8 10 12 14 0.D. 16 O.D. 18 O.D. 20 O.D. 24 O.D. 30 O.D. 36 O.D. 42 O.D. 48 O.D. 314 3% 4 4)4 5 5)4 6 6M m 8 9 11 12 14 15 16)4 18 22 25 28 31 34 - 7 1)4 8 9 10 11 12 13 15 16 18 22 24 28 30 33 36 44 50 56 62 68 5 5)4 6 6)4 7 m 8)4 9 10M \m 14 16)4 19 21)4 24 26)4 29 34 41)4 49 56)4 64 m 2 2K 2)4 3 3 3)4 4 4)4 5 5)4 6H 7)4 1)4 8 8)4 9)4 11 15 18 21 24 4X m 5 6 7 8)4 9 10 11 13H 16 19 21 23)4 25 27)4 32 38% 46 53 59)4 % H % Vs, % H >ks 'Hs % 1 1X m 1 imm% VA 2)4 2H 2Vs 2% % f*6 % % 'H )4 %> H % % i iks 1 Vs iH imks. i% 2 AU dimensions given in inches. - ` -_ Crosses both straight and reducing sizes 18 in. and larger shall be reinforced to compensate for the in herent weakness in the casting design. b Size of all fittings listed indicates nominal inside diameter of port. Tees, side outlet tees, and crosses. 16 in. and smaller, reducing on the outlet, have the same dimensions center to face, and face to face as straight size fittings corresponding to the size of the larger opening. Sites 18 in. and larger, reducing on the outlet, are made in two lengths, depending on the size of the outlet. ^ d Tees and crosses, reducing on run only, carry same dimensions center to face and face to face as a straight size fitting of the larger opening. Reducing elbows and side outlet elbows carry same dimensions center to face as straight size elbows corresponding to the size of the larger opening. 1 Special degree elbows, ranging from 1 to 45 deg, inclusive, shall have the same center to face dimensions as given for 45-deg elbows, and those over 45 deg and up to 90 deg, inclusive, shall have the same center to face dimensions as given for 90-deg elbows. The angle designation of an elbow is its deflection from straigm line flow and is the angle between the flange faces. . * Side outlet elbows shall have all openings on intersecting center lines. h Body thickness at no point shall be less than 871 percent of the dimensions given in the table. Nominal Pin Sox Ootsidb Diameter . Centsr-to-End 90-Deg - Elbows A 4$^Deg Elbows B Of Rod Tee C* i Di 1)4 2 2)4 3 3)4 4 5 6 8 10 12 1.315 1.660 1.900 2.375 2.875 3.500 4.000 4.500 5.563 6625 8625 10.750 12.750 Di i% 2K 3 3>A 4)4 5% 6 1)4 9 12 15 18 % i 1)4 m iH 2 2K 2)4 3)4 3M 5 6)4 1)4 - l)i m 2)4 2)4 3 3)4 3% m 4% 5)4 7 8)4' : 10 Cabp.os 1)4 1)4 D4 1)4 1)4 2 2)4 2)4. 3 3H 4 5 6 Lapped-Joikt Stub Ends LeFnbgth 4 4 4 6 6 6 6 6 8 8 8 10 10 Radius of Fillet R y* Me M Me Me *A Mt Me Me V4 )4 )4 )4 Oi&m. of ft 2 2)4 214 3)4 4)4 5 5)4 6Me IMe 8)4 16)4 12M 15 All dimensions given in inches. ; , * The dimensions of welding tees cover those which have side outlets from one size less than half thesise of tne run-way opening of the tees, to full size. i?. Dimensions and F are applicable only to these fittings in schedules up to and including Schedule 80, ASA Standard B36.10-19S9. * The shape of these caps shall be ellipsoidal and shall conform to the requirements of the A.S.MJ2. Boiler Construction Code. d This' dimension is for standard machined facings in accordance with American Standard for Steel Pipe and Flanged Fittings (ASA B16e-1939). The back face of the lap shall be machined to conform to tne surface of the flange on which it seats. Where ring joint facings are to be applied, use dimension K as given in ASA B16e-1939. responsibility. Thus the employer should 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 at regular intervals subject their work to prescribed tests. Rules for fusion welding of pipe joints, the qualification of welding operators, welding procedures and the testing thereof, are contained in the Standard Manual on Pipe Welding of the Heating, Piping & Air Con ditioning Contractors National Association, and in publications of. other Sfoups.'A.s jn general, the wall thickness and chemical analysis of the Pipe are the governing factors, not the working pressure. There are a number of safety codes which govern the installation of welded piping in 620 CHAPTER 27 1954 Guide many cities and states, Some of the more prominent are listed at the end of this chapter.4-s-' - A. complete line of manufactured steel nuumg ..fi++mrro VeiCUGg, iiiMMiigu ... _ . :iq AUT OVP7!fl.VlIf lO uw* and a dimensional standard7 has been prepared under the procedure of the American Standards Association to unify heretofore divergent dimensions 10.Table American Standard Dimensions op Steel Welding Neck and Slip-on 160 PSIWelding Flanges fob Steam Service Pressure Rating of (Gage) 500 F, 100 PSI 760 F,at a Temperature of and (Gage) at ASA B16e-1939 pipe, Fittings, Welding 621. in some types of fittings. The welding bevel which is a.straight 37^-deg V for wall thickness f ip. and below, and a U-bevel for thicknesses heavier than in., conforms to the recommended practice of ASA Standard Bioe-1939, American Standard for Steel Pipe Flanges and Flanged Fittings. The latter also contains dimensions for steel, welding neck flanges for pressures up to 2500 psi, and slip-on welding flanges for 150 and 300 psi. Table 10 gives these dimensions for welding-neck and slip-on welding flanges suitable for 150 psi gage pressure. Socket-welding fittings also are commercially available. These fittings have a machined recess for inserting the pipe which is attached by a Table 11. Amebican Standard Dimensions or Socket-Welding Elbows, Tees, Cbosses, 45-Deg Elbows, and Couplings Nomnaj. PlPB Sm 0?DuUITtB Thickness Fio. Flangb Min. Dumb-tee Of Hob Hub Duil Beginning CnAuorrzn1'--' B Length Tbbo Hob* Iksipb Duh. or Pits Schedule 40c Bore or Slqcon Funqes Mm. Duu. or Bolt Cibcls Ka *6 %. is 2 2*6 3 m 4 5 6 8 10 12 14 O.D. 16 O.D. 18 O.D. 20 O.D. 24 O.D. 3*6 m 4*6 m 5 6 7 m 8*6 9 10 11 13*6 16 19 21 23*6 35 27*6 32 %m *6 1*6 % i% 2*6 % 316 %m m % 4% % 5*6 % 6*6 7*6 in 9% 12 ip 14*6 15*6 18 m 19% i% 22 m 26*6 0.84 1.05 1.32 1.66 1.90 2.38 2.88 3.50 4.00 4.50 5.56 6.63 8.63 10.75 12.75 14.00 16.00 18.00 20.00 24.00 % i 216 2*6 2*6 2*6 2% 3 3*6 3*6 4 4 4*6 5 5 5*6 5% 6 I 0.62* 0.82* 1.05* 1.38* 1.61* 2.07* 2.47* 3.07* 3.55* 4.03* 5.05* 6.07* 7.98* 10.02* To Be Specified by Purchaser 0.88 1.09 1.38 1.72 1.97 2.44 2.94 3.56 4.06 4.56 5.66 6.72 8.72 10.88 12.88 14.19 16.19 .18.19 20.19 24.19 22**66 3*6 3*6 3*6 4*6 5*6 6 7 7*6 8*6 9*6 n*6 14*6 17 18*6 21*6 22*6 25 29*6 Sub or Boms All dimensions given in inches. .. , * A raised Isoe of Ms in. is included in thickness offlange minimum and in length through huh. - 8 The outside surface of the welding end of the bub shall be straight or tapered at not more than 6 deg. 0 Dimensions B and J correspond to the outside and inside diameters of pipe as given in ASA B36.10*, 1939, TShcehseedudlieam40e.ters are identical with the diameters of what was formerly designated as Standard Weight Pipe of the corresponding sues. for the same type welding fittings as produced by different manufacturersStandard dimensions for steel butt-welding elbows, tees, caps, and lapped- joint stub ends are given in Table 9. Dimensions for eccentric and con centric reducers, and 180-deg return bends are not shown in Table 9, but are included in the American Standard. Larger sizes also are available- All dimensions are given in inches. a Dimension C is II times the nominal pipe thickness, minimum, but not less than H in. ' Reducing sizes have eame center to bottom of socket dimension as the largest size of reducing fitting. fillet weld between the pipe wall and socket end. Use of socket-welding fittings generally is restricted to nominal pipe sizes 3 in. and smaller in which range commercial 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 weakening the pipe, as is the case with threading. Dimensions for socket-welding fittings, in accord ance with ASA Standard B16.11-1946, are given in Table 11.8 VALVES Valves are made with both threaded and flanged ends for screwed and bolted connections just as are pipe fittings. 622 CHAPTER 27 1954 Guide The material used for valves of small size is generally brass or bronze for low pressures and forged steel for high pressures, while in the larger sizes either cast-iron, cast-steel or some of the steel alloys are employed. Practically all iron or steel valves intended for steam or water work are bronze-mounted or trimmed. Brass, bronze, and iron valves are generally designed for standard or extra heavy service, the former being used up to 125 lb and the latter up Table 12. American Standard Contact Surface to Contact Surface Dimensions of Cast-iron and Steel Flanged Wedge Gate Valves, All dimensions given in inches. * These nni are the same for Cast-Iron Double-Disc Flanged Gate Valves. b These are pressure designations which refer to the primary service ratings in pounds per square inch of the connecting end flanges. . - 0 The connecting end flanges of 175 lb valves are the same as those on 250 lb valves. Notb 1 '.--Where dimensions are not given, the sizes either are not made or there is insufficient demand to warrant the expense of unification. Note 2Female and groove joint facings have bottom of groove in same plane as flange edge, and center to contact surface dimensions for these facings are reduced by the amount of the raised face. to 250 lb saturated steam working pressure, although most manufacturers also make valves for medium pressure up to 175 lb steam working pressure. The more common types are gate valves or straightway valves, globe valves, angle valves, check valves and automatic valves, such as reducing and back-pressure valves. Gate valves are the most frequently used of all valves since in their open position the resistance to flow is a minimum, but they should not be used where it is desired to throttle the flow; globe valves should be used for this purpose. Gate valves may be secured with either a rising or a non rising stem, although in the smaller size the rising stem is more commonly, used. The rising stem valve is desirable because the positions of the Pipe, Fittings, Welding 623 handle and stem indicate whether the valve is open or closed, although space limitations may prevent its use. The globe valve is less expensive to manufacture than the gate valve, but its peculiar. construction offers a high resistance to flow and may prevent complete drainage of the pipe line. These objections are of particular importance in heating work. An American Standard, ASA B16.10-1939, has been prepared giving the face-to-face dimensions of ferrous flanged and welding-end valves. The following types are covered: wedge gate, double disc gate, globe and angle, and swing check. One purpose of establishing these dimensions, is to insure that gate valves of a given rating and flange dimension of either, the wedge or double disc design will be interchangeable in a pipe line. Contact surface to contact surface dimensions of cast-iron and Steel flanged wedge-gate valves are given in Table 12. End-to-end dimensions for steel butt-welding valves in sizes up to 8 in., inclusive, are the same as those given in Table 12 for steel valves. Check valves are automatic in operation and permit flow in only one direction, depending for operation on the difference in pressure between the two sides of the valve. The two principal kinds of check valves are the swing check in which a flapper is hinged to swing back and forth, and the lift check in which a dead weight disc moves vertically from its seat. Valves commonly used for controlling steam or water supply to radi ators constitute a special class since they are manufactured to meet heating system requirements. These valves are generally of the angle type and are usually made of brass. Graduations on the heads or lever handles are often supplied to indicate the relative opening of the valve. Automatic control of steam supply to individual radiators can be ef fected by use of direct-acting radiator valves having a thermostatic element at the valve, or near to it. The direct-acting valve is usually an angle-type valve containing a thermostatic element which permits the flow of steam in accordance with room temperature requirements. These valves usually are capable of adjustment to permit variation in room temperature to suit individual taste. Ordinary steam valves may be used for hot water service by drilling a lA-in. hole through the web forming the seat to insure sufficient circulation to prevent freezing when the valve is closed. Valves made for use in hot water heating systems are of simpler design, one type consisting of a simple butterfly valve, and another of a quick opening type in which a part in the valve mechanism matches up with an opening in the valve body. 1 In one:pipe steam-heating systems, automatic air valves are required at the radiators. Two common types of air valves available are the vacuum type and the straight-pressure type. Vacuum valves permit the expulsion of air from the radiators when the steam pressure rises and, in addition, act as checks to prevent the return of air into the radiator when a vacuum is formed by the condensation of steam after the supply pressure has dropped. Ordinary air valves permit the expulsion of air from the radiator when steam is supplied under pressure, but when a vacuum tends to be formed the air is drawn back into the radiator. REFERENCES 'See (1) Piping Handbook, by Walker and Crocker (McGraw-Hill Co.); (.2) A Manual for The Design of Piping for Flexibility by the Use of Graphs, by E. A. WWeert, " ^roith, E. T. Cope (The Detroit Edison Company). * ee API Specification 5L for Line Pipe, American Petroleum Institute. * Standard Manual on Pipe Welding (Heating, Piping and Air Conditioning Con 624 CHAPTER 27 1954 Guide tractors National Association, Second Edition, 1951). Welding Handbook (American Welding Society, 1942).. . .. * ASME Power Boiler Code. American Society of Mechanical Engineers. 5 American Standard Code for Pressure Piping, ASA B-31:1--1942, American Sta8nMdaarrdinseAsEsnogciinaetioenri.n- g Regulations of the Coast Guard, American Bureau of Ship- ping- . .. : . '' General Specifications for Inspection of Material, Appendix VII, Welding, U. S. Navy. Specifications for Welding, Appendix 5, Part 1--General--for vessels of the .U.7 SA.mNearivcya,nBuSrteaanudaorfd.S, hSiptese, lABpuritlt,-W19e40ld. ing Fittings, ASA B16.9-1940, American ' Sta8nAdmaredrsic.AasnsSoctaiantidoanr.d, S t,eel Socket-Weld ing Fittings; ASA B16.11-1946, American Standards Association. . . . ... CHAPTER 28 PIPE INSULATION Heat Losses from Bare and Insulated Pipes, Low Temperature Pipe Insulation, Insulation of Pipes to Prevent Freezing, Economical Thickness of Pipe Insulation, Underground Pipe Insulation THE heat loss from uninsulated pipes may be of considerable magni tude if the temperature of the surrounding medium differs appre ciably from that of the fluid conveyed. Losses are increased by rapid motion of the surrounding air or by contact of the pipe with bodies of high conductivity. Careful consideration must, therefore, be given to this factor in a properly designed system, and adequate insulation pro vided, if necessary. ' ' HEAT-LOSSES FROM BARE PIPES 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 1. Heat losses from horizontal copper tubes and pipes with tarnished surfaces, are given in Table 2.1 Heat losses from bare pipe , of materials having lower emissivities may be calculated from data appearing in Chapter 5. . . ... , The area in square feet per linear foot of pipe is given in Table 3 for various standard pipe sizes, and Table 4 for copper tubing, while Table 5 gives the area in square feet of flanges and fittings for various standard pipe sizes. These tables can be used to advantage in estimating the amount of insulation required. . Very often, when pipes are insulated, flanges and fittings are left bare so as to allow for'easy access to the fittings in case of repairs. The fact that a pair of 8-in. standard flanges having an area of 2.41 sq ft would lose, at 100 lb steam pressure, an amount of heat equivalent to more than a ton of coal per year, shows the necessity for insulating such surfaces. Examples 1 and 2 show how the annual heat loss from uncovered pipe and its dollar value may be computed from the data in Table 1. -...... 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 carrying steam at 10 lb pressure and is exposed to an average air temperature of 70 F. Solution: The pipe temperature is taken as the steam temperature, which is 239.4 J obtained by interpolation from Steam Tables. The temperature difference be tween the pipe and air = 239.4 - 70 = 169.4 F. By interpolation of Table 1 between temperature differences of 157.1 and 227.7 F, the heat loss from a 2-in. pipe at a tem perature difference of 169.4 F is found to be 1.624 Btu per (hr) (linear ft) (F deg). Th total annual heat loss from the entire line -- 1.624 X 169.4 X 165 (linear ft) X 4000 w) ** 181,600 Mb. (Mb - 1000 Btu.) ~- Example 2: Coal costing $11.50 per ton and having a calorific value of 13,000 Btu pound is being burned in the furnace supplying steam to the pipe line given in the Previous example. If the system is operating at an overall efficiency of 55 percent, etermine the monetary value of the annual heat loss from the line. (a The cost of heat per 1000 Mb supplied to the system = 1,000,000 X 11.5 wjUars) + [13,000 (Btu) X 2000 0b) X 0.55 (efficiency)] = $0,804. The total cost ' ^eat* lost per year 0.804 X 181.6 (thousand Mb) *= $146.00. : 625 CHAPTER 28 1954 Guide 626 - XPTJUIPTUE INSULATIO----N----S--- Pipe insulations are of several general forms and are made of various types of material. The most common form is the rigid sectional covering either split longitudinally into halves or cut through on one side and scored on the other, to facilitate assembling on pipes. Preformed ma- Table 1. Heat Losses from Horizontal Babe Steel Pipes . Expressed in Btu per (hour) (linear foot) (Fahrenheit degree difference between the pipe and surrounding still air at TO F) Table 2. Heat Loss fbom Horizontal Tabnished Copper Pipe Expressed in Btu per (hour) (linearfoot) (Fahrenheit degree difference between the pips and surrounding still air at TO F) Nominal Pips Silk (Inches) Hot Water (Type K Copper Tube) 120 F 150 F 180 F 210 F Steam (Standard Pipe Sire Pipe) 227.1 F (5 Lb) 297.7 F (50 Lb) 337.9 F (100 Lb) Temperature Difference is2 2H 3 3H 4 4H 56 8 50 F 0.250 0.340 0.440 0.500 0.580 0.730 0.880 1.040 1.180 1.460 L600 1.810 2.400 80 F 0.287 0.381 0.475 0.559 0.656 0.825 1.000 1.175 1.350 1.500 1^812 2.125 2.685 110 F 0.300 0 409 0.509 0.618 0.710 0.890 1.091 1.272 1.454 1.635 1.980 2.270 2.910 140 F 0.321 0.429 0.536 0.622 0.750 0.957 1.143 1.343 1.535 1.715 27071 2.430 3.110 157.1 F 0.433 0.533 0.636 0.764 0.904 1.101 1.305 1.560 1.750 1.941 2.131 2.387 2.740 3.310 227.7 F 0.500 0.543 0.746 0.878 1.053 1.273 1.490 1.800 2.020 2.240 2.465 2.770 3.210 4.050 267.9 F 0.530 0.654 0.803 0.934 1.120 1.364 1.605 1.940 2.170 2.430 2.650. 2.990 3.440 4.370 teriais are supplied in segments lor assembly on large pipes. The sectional coverings are generally supplied with a pasted-on canvas jacket. Blanket ire sometimes used for wrapping large pipes, particularly insulations are wanhderebernedmsoavrael fcsooormmfmreetoqimnueleysn.tcuossveeerurveicd1iUn1wgitohf *pthvo,eortinpoiinnpspe oiif?sf nnseextaccen^esdsssaaa. rrrdyy., Fittings preform1 Pipe Insulation 627 Table 3. External Surface peb Linear Foot of Pipe Nominal Pipe Size (Inches) X H I1K 1H Surface Area (Sq Ft) 0.22 0.275 0.344 0.435 0.498 Nominal Pipe Size (Inches) 2 3 m 4 Surface Area (So Ft) 0.622 0.753 0.917 1.047 1.178 Nominal Pipe Size (Inches) 5 6 8 1120 Surface Area (So Ft) 1.456 1.734 2.257 2.817 3.338 Table 4. External Surface per Linear Foot of Copper Tubing Outside diameter J in. greater than nominal size Tube Size . (Inches) HH 1 . 1H 1H Surface Area (Sq Ft) 0.164 0.229 0.295 0.360 0.426 Tube Size (Inches) 2 2X 3 3K 4 Surface Area (So Ft) 0.556 0.687 0.818 0.949 1.080 Tube Size (Inches) 5 6 8 Surface Area (So Ft) 1.342 1.604 2.128 insulation or, when' irregular in contour, with plastic materials known as insulating cements. Insulation is secured to pipes with staples which are used to bridge the joint between half sections, and with metal pipe covering bands or rings of wire which secure individual sections and effect a junc tion between abutting sections. Surface finishes used over pipe insulation depend upon the service encountered and appearance desired. Canvas jackets are most common, although asbestos paper or asbestos finishing cements are sometimes employed. Insulation outdoors should be water proof, and is generally protected with an asphalt felt for piping and asphaltic cements for fittings. Insulation on lines carrying cold water, brine, or other cold fluids is carefully finished to obtain adequate sealing against the penetration of water vapor. The selection of pipe insulation for a particular service condition must be made with full consideration of a number of properties in addition to thermal conductivity. Factors which may be of more importance than the thermal conductivity are: ease of application, fire resistance, heat, stability; weathering stability, resistance to damage by physical. abuse, and others which may apply to a particular installation. A complete Table 5. Area of Flanged Fittings, Square Feet* Nominal Pipe Skb (Inches) 1 IK i* 6 8 10 * 12 Flanged Coupling Standard Extra Heavy 0.320 0.383 0.477. 0.672 0.841 0.945 1.122 1.344 1.474 1.622 1.82 2.41 3.43 4.41 0.438 0.510 0.727 0.848 1.107 1.484 1.644 1.914 2.04 2.18 2.78 3:77 5.20 6.71 90 Deg Ell Standard Extra Heavy 0.795 0.957 1.174 1.65 2.09 2.38 2.98 3.53 3.95 4.44 5.13 6.98 10.18 13.08 1.015 1.098 1.332 2.01 2.57 3.49 3.96 4.64 5.02 5.47 6.99 9.76 13.58 17.73 Long Radius Ell Standard Extra Heavy 0.892 1.084 1.337 1.84 2.32 2.68 3.28 3.96 4.43 5.00 5.99 8.56 12.35 16.35 1.083 1.340 1.874 2.16 2.76 3.74 4.28 4.99 5.46 6.02 7.76 11.09 15.60 18.76 Tee Standard Extra Heavy 1.235 1.481 L815 2.54 3.21 3.66 4.48 5.41 6.07 6.81 7.84 10.55 15.41 19.67 1.575 1.925 2.68 3,09 4.05 5.33 6.04 7.07 7.72 8.52 10.64 14.74 20.41 26.65 Cross - Standard Extra Heavy 1.622 1.943 2.38 3.32 4.19 4.77 5.83 7.03 7.87 8.82 10.08 13.44 19.58 24.87 2.07 2.53 3.54 4.06 5.17 6.95 7.89 9.24 10.07 10.97 13.75 18.97 26.26 34.11 k^uding areas of accompanying flanges bolted to the fitting. '-3S3SE 628 CHAPTER 28 1954 Guide Table 6. Thermal Conductivity (At) of Various Type Pipe Insulations for Medium and High Temperature Pipe* '. Expressed in Btu per {hour) (square fooi) {Fahrenheit degree temperature difference per inch) Types of Insulating Materials Density Lb/Cu Ft Temp. Range Use Mean Temperature, F 100 200 300 400 11-14 Up to 600 F 0.39 0.45 Corrugated Asbestos--Type Laminated Asbestos--Type^ ^ Brown Asbestos Fiber^-Type........................... 11-13 15-17 18-20 30-35 10-15 25-30 13-15 up to 300 E Up to 300 F Up to 300 F Ud to 700 F Up to'800 F Up to 1800 F Up to-1200 F- 0.57 0.88 0.80 Un'.49 0.39 0.44 0.49 0.40 0.34 * Average values from laboratories for insulating materials, of various manufacturers. 0.51 l- 0.54 0.55 0.72 0.49 0.75 0.54 evaluation of pipe insulation cannot be included here. Insulation manu facturers should be consulted in regard to the selection of insulation which is to meet specific requirements. : Elbows and fittings should be covered with an insulation of equal thick ness and material which is similar to the. pipe covering. Pre-fabricated fittings are available for many types of insulation, such as cork and rock cork. Where asbestos cement or magnesia cement is used to build up the fittings, the material should be. applied in layers not exceeding a thickness of % in. The final coat should be mixed with 10 percent Portland cement and troweled smooth. After the final coat has thoroughly dried, it is recom mended that canvas of, the same weight as that used pn the pipe covering be pasted over the surface. This procedure will prevent the built up portions of the covering from falling off due to a slight bump or other miOnonr pdearmmaagnee. nt installations o..f high quality, it is recommended that all coverings and fittings be further encased in 8-oz. canvas, drawn tight over rosin-sized paper and.sewed in place, using not less than four stitches per inch. . .... ' HEAT LOSSES FROM INSULATED PIPES The conductivities of various materials used for insulating steam and hot water systems are given in Table 6. They are given as functions of the mean temperatures or the arithmetic mean of the inner and outer surface temperatures of the insulations. It should be emphasized that they are the average values obtained from a number of tests made on each type of material; also, that in the use of conductivity all variables due to differences in thickness, pipe sizes, and air conditions, are eliminated- Table 7. Pipe Covering Factors . i Temperature Difference, Pipe to Ais, F Deo 500 Corrugated Asbestos--Type 4 Ply per 1 in. 6 Ply per 1 in. 8 Ply per 1 in.................. laminated Asbestos--Type. Mineral Wool--Type............... Diatoxnaceous Silica--Type Brown Asbestos Fiber--Type Pipe -Insulation 629 Individual; manufacturer's materials will, of course, vary in conductivity; to some;extent from these values. . ./il-i-ni The heat losses through 1, 1, and 2-in. thick, 85 percent magnesia type of insulation for temperature differences between the;pipe and-the surrounding atmosphere up to 280 F, are shown in Figs.- I, 2\ and Sv -------- ,,--i nmiuun I in. I HICK 85 PERCENT MAGNESIA TYPE - Covering exapfi^^ thicknesses of 85 percent magnesia pipe covering are not can ' 'n'. However, the loss through any given thickness of insulation insi 1 ^^ined by interpolation. Also, the losses through any of the obt ons S'ven in Table 6 can be obtained by multiplying the losses med from Figs. 1, 2, or 3 by the factors given in Table 7. *Pes operating at high temperatures are frequently insulated to the 630 CHAPTER 28 ` 1954f.GuidS best advantage by combining a high temperature insulation near the pipe with a moderate or low temperature insulation around it as an outer layer. By this method an efficient material may be used for each of the two tem perature 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 three or four calculations performed as a series of approximations, in which assumptions Ripe Insulation 631. r, -- outer radius of. insulation, inches. . k = thermal conductivity of insulation, Btu per (hour) (square foot) (Fahrenheit degree per inch). 1, = temperature of inner surface of insulation, Fahrenheit degrees. t, = temperature of outer surface of insulation, Fahrenheit degrees. . It is convenient to work from the outer surface of the insulation, since the loss through the covering must be determined from the outer surface loss by means of surface loss curves such as given in Fig. 4. Fio. 2. Heat Loss Through 1} In. Thick 85 percent Magnesia Type Covering of thickness and mean temperature are adjusted as indicated in the dis cussion which follows. In the case of a single thickness of pipe covering, the quantity of heat transferred per square foot of outer surface of the insulation is given by the equation: - fc(ti -- h) q` . r, rj log. T\ (1) . where q0 = Btu per (hour) (square foot of outer surface of insulation). ri = outer radius of pipe or inner radius of insulation, inches. . Fig. 3. Heat Loss Through 2 In. Thick 85 percent Magnesia Type Covering After the true heat loss is obtained, the loss per square foot of pipe sur face can be calculated from the relationship: ' 9. = qJji/ri) Aere ?i = Btu per (hour) (square foot outer surface of pipe). The heat loss through two or more thicknesses of insulation applied to a P'pe can be calculated by means of the equation: 'here r, ' r. q, = t, - t. r. log. + outer radius of second layer of insulation, inches, outer radius of last layer of insulation, inches. (2) 632 CHAPTER 28 1954'Guide The method of solving Equation 2, which is the most difficult' of the twdyis'pven-in -Example -8. / = Example 3:. Compute the heat loss per linear foot of pipe surface per hour from a 6-in. pipe, insulated with a 3-in. thickness of diatomaceous silica, and a 2-in. thick ness 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: rIn figuring the heat loss from Equation 2, it is necessary to first make ah' assumption for the outer surface temperature ii and .the temperature between the; diatomaceous silica and 85 percent magnesia insulation, so that the mean tempera ture of each material can be obtained and the thermal conductivity corresponding to the mean temperature of each material substituted in the formula. First assume an Fig 4 Heat Loss from Canvas-Covered Cteindiucal Surfaces of tio. 4. I1EA1 U Various Diameters outer surface temperature of 140 F and a temperature of 570 F between the ;two maii terials corresponding to a mean temperature of (1200 + 570) 2 or 885 F for the dia tomaceous silica and (570 + 140) 2 or 355 F for the 85 percent magnesia insulation. The conductivities of these two materials at mean temperatures of 885 and 355 F, interpolated from Table 6, are 0.865 and 0.5 Btu, respectively. These values are substituted in Equation 2 and a trial calculation made.' For. a nominal 6-in. steel pipe: n = 3.312, rt = 6.312, and r, = 8.312. Then, f- 1200 - 140 1060 = 98.3 Btu. q. 6.312 8.312 log, 3.312 8.312 8.312 log. 6312 6.2 4- 4.85 0.865 + 0.5 The temperature drop from the outer surface of the insulation to the surround's?' air for a heat loss of 98.3 Btu is found from Fig. 4 to be 57 deg for a 16-in. O.D. cyu' drical surface, or 57 + 80 F room temperature = 137 F surface temperature. Since Pipe Insulation 633 surface temperature of 140 F was assumed, it is evident that a temperature closer to 137 F, or, for instance, 138 F should be used for recalculation: 1200-- 138 6.2 + 438 98.4 Btu. Since the temperature drop through each material is equal to the heat flow times the actual resistance of each material, the temperature drop through the diatomaceous silica is 98.4 X 6.2 = 610 F, or the temperature between the two insulating materials is (1200 -- 610) = 590 F. Since a temperature of 570 F between the two materials was assumed, it is obvious that a temperature closer to 590, or for instance 586 F may be selected. The mean temperatures of the two insulations corresponding to the new assumptions are (1200 + 586) -5- 2 = 893 and (586 + 138) E 2 = 362, and the inter polated conductivities corresponding to the new mean temperatures are 0.87 and 0.505 for the diatomaceous silica and 85 percent magnesia, respectively. By sub stituting in Equation 2 1200 - 138 5.36 2,29 0.87 + 0.505 1062 6.16 + 4.58 99.3 Btu. Again referring to Fig. 4, it is seen that the temperature drop from the outer sur face of the insulation to the surrounding air for a heat loss of 99.3 Btu = 58 deg, which corresponds to the surface temperature of 138 F last assumed. The temperature drop through the diatomaceous silica is 99.3 X 6.16 = 612 F, corresponding to a tem perature of 588 F between the two materials, which checks very closely with the tem perature of 585 F last assumed. The heat loss is therefore 99.3 X 8.312 -s- 3.312 or 249 Btu per sq ft of pipe surface. Since the surface area per linear foot of 6-in. pipe is 1.734 sq ft (Table 3), the heat loss per linear foot of pipe will be 249 X 1.734 = 432 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 case 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 flowing over the surface of the insulation can 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, pro vided that the insulation is thoroughly sealed so that air can flow only over the surface. If the conditions are such that the air may circulate through cracks and crevices in the insulation, 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,us 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 resisting paint, such as black asphaltum. This precaution may prevent early failure due to external pipe corrosion. : Kg. 4 shows the loss of heat from canvas-covered, cylindrical surfaces of various outside diameters when the surface to air temperature difference 13 low. The data are from tests made at Mellon Institute. The frequent practice of omitting insulation on that portion of a pipe mch passes through a masonry wall, or which may be in contact with other metals, should be avoided. Physical contact between the pipe sur- ace and other structural materials of high thermal conducitivity- will re- 634 CHAPTER 28 1954 Guide suit in heat transfer much greater than that shown in Tables 1 and 2 for transfer from bare pipe to air. ' The saving due to use of insulation on piping is illustrated in Example 4- Example 4'-. If the steam line given in Examples 1 and 8 is covered with 1 in. thick 85 percent magnesia, determine the resulting total annual loss through the insulation. Also compute the monetary value of the annual saving and the percentage of saving over the heat loss from the bare pipe. Solution: By referring to Fig. 1, the coefficient for 1 in. magnesia on a 2-in. pipe is found to be 0.300 Btu per (hr) (linear ft of pipe) (deg temperature difference) at a temperature difference, of 169.4 F. The total hourly loss per linear foot of pipe will then be 0.300 X 169.4 = 50.8 Btu. The total annual loss through the insulation = 50.8 X 165 (linear ft) X 4000 (hr) = 33,500 Mb. The annual bare pipe loss as deter mined in the solution of Example 1 was found to be 181,600 Mb. The saving due to insulation is then 181,600 -- 33,500 = 148,100 Mb per year. From the solution of Example 8, it was found that the heat supplied to the system cost $0,804 per thousand Mb. Therefore, the monetary value of the saving = 0.804 (dollars) X 148.1 (thousand Mb) = $119.07, or 81.5 percent of .the cost when using uninsulated pipe. LOW TEMPERATURE PIPE INSULATION Surfaces maintained at temperatures lower than the surrounding 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 conduc tivity of the material. This property is particularly important in the insulation of surfaces that are below the dew-point of the surrounding 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 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 pro ducing vapor seals, some of which have been worked out by insulation manufacturers to suit their products, and others by applicators and users. Unless time-proven methods are known, specifications of insulation man ufacturers should be obtained and followed carefully. Piping must be carefully protected against corrosion caused by condensa tion 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 condensation 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 ascertained from a psychrometric chart. The external vapor barrier must be made as nearly perfect as possible in order to prevent leakage of vapor into the insulation. The approximate required thickness of insulation to prevent condensa tion on pipes and flat metallic surfaces may be obtained from Fig. 5 m which a surface resistance of 0.606, corresponding to a film conductance of 1.65, was used in calculating 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 Pipe Insulation 635 Fig. 5. Thickness of Pipe Insulation to Prevent Condensation on Outer Surface* the next thinner, commercial insulation in cases where an intermediate thickness is indicated. Heat gains fpr pipes insulated with a material having an installed condueitivity 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 0.3 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 velocity that the quantity of heat carried in the water is not sufficient to take care of the heat losses which will result and 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, and if the velocity of the water flowing in the pipe is main tained at a sufficiently high rate, freezing may be prevented. Table 9 may be used for making estimates of the thickness of insula tion necessary to take care of still water in pipes at various water and surrounding air temperature conditions. Because of the damage and 636 CHAPTER 28 1954 Guide service interruptions which 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 conductivit}' of 0.30. The initial water tem perature is assumed to be 10 deg above, and the surrounding air temperature 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 which 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 column should be multiplied by the total length of the exposed pipe line expressed in feet. As an additional factor of safety, and in order to provide against temporary reductions in flow occasioned by reduced pressure, it is ad- Table 8. Heat Gains fob Insulated Cold Pipes Rates of heat transmission given in Btu per {hour) (Fahrenheit degree temperature difference between fluid in pipe and surrounding still air) . Based on materials having conductivity, k = 0.S0 Nominal Pipe Size (Inches) 2M 3 3X 4 56 8 10 12 Ice Water Thickness Brine ThicknESS Heavy Beine Thickness Thickness of Insulation (Inches) Btu Per Linear Foot Btu Per Sq Ft Pipe Surface 1.5 1.6 1.6 1.6 1.5 1.5 1.5 1.5 1.5 1.7 1.7 1.7 1.9 1.9 1.9 0.110 0.119 0.139 0.155 0.174 0.200 0.228 0.269 0.295 0.294 0.349 0.404 0.455 0.559 0.648 0.502 0.431 0.403 0.357 0.351 0.322 0.303 0.293 0.282 0.248 0.239 0.233 0.201 0.198 0.194 Thickness of Insulation (Inches) Btu Per Linear Foot Btu Per Sq Ft Pipe Surface 2.0 22..00 2.4 2.5 2.5 2.6 2.7 2.9 2.9 3.0 3.0 3.0 3.0 3.0 0.098 am 0.124 0.131 0.134 0.151 0.170 0.186 0.191 0.209 0.241 0.259 0.318 0.383 0.438 0.446 0.405 0.352 0.300 0.270 0.244 0.226 0.202 0.183 0.176 0.165 0.150 0.140 0.135 0.131 Thickness of , Insulation (Inches) Btu Per Linear Foot Btu Per Sq Ft Pipe Surface 2.8 2.9 3.0 3.1 3.2 3.3 3.3 3.4 3.6 3.7 3.9 4.0 4.0 4.0 4.0 0.087. 0.094 0.104 0.113 0.118 0.134 0.147 0.162 0.176 0.182 0.202 0.228 0.263 0.309 0.364 0.394 0.340 0.294 0.260 0.238 0.214 0.197 0.176 0.167 0.154 0.138 0.130 00..111160 0.108 visable to double the rates of flow listed in the table. It must be empha sized 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 52 F instead of 42 F, the time required to cool it to the freezing point will be prolonged to twice that given in the table, or the rate of flow of water may be reduced so that the quantity required will be one-half that shown in the last column 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 time 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 Table 9. Nominal Pipe Size (Inches) Data fob Estimating Requibements to Pbevent Fbeezing of Watek in Pipes with Subbounding Aib at --18 F rT Number of Hours to Cool 42 F Water Flow Required at 42 F to Water to Freezing Point Prevent Freezing. Pounds per Linear Foot of Pipe per Hour X 1 1)4 2 43 5 8 10 12 L2 J 0.42 I 0.83 1 1.40 I 1.94 1 3.25 1 4.55 I 5.92 1I 7.35 1 10.05 I 13.00 1 15.80 Thickness of Insulation in Inches (Conductivity, k = 0.30) 3 0.50 - 1.02 1.74 2.48 4.27 6.02 7.96 9.88 13.90 18.10 22.20 4 0.57 1.16 2.02 2.90 5.08 7.20 9.69 12.20 17.25 22.70 28.10 2 . 0.54 0.68 0.84 0.95 1.24 1.47 1.73 1.98 2.46 2.96 3.43 34 0.45 0.40 0.55 0.48 0.68 ' 0.58 0.75 0.64 0.94 0.79 1.11 0.93 1.29 1.06 1.46 1.19 1.78 1.43 2.12 1.70 2.45 . 1.93 cue outer suriace ot tne insulation to the transfer of heat to the air, have all been neglected. When 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 freezing starts. The flow 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. 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 line, or to place an electric resistance heater along the side of the exposed water line. The heating system and the water, line are 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. For this form of protection 2 in. of an efficient insu lation may be applied. . ____ -- va .itLf MlOUiiAiiV/11 The thicknesses of insulation which ordinarily are used for various temperature conditions are given in Table 10. Where a thorough analysis of economic thickness is desired, this may be accomplished through the use of the chart, Fig- 6. The . dotted line on the chart illustrates its use in solving a typical Table 10. Thickness of Pipe Insulation Obdinabily Used Indoobs* Steam Pressure Psjg or Condition 0to 25 25 to 100 . 100 to 200 j-pw Superheat Medium Superheat High Superheat Steam Temperature Fahrenheit Degrees 212 to 267 267 to 338 338 to 388 388 to 500 500 to 600 600 to 700 Thickness of Insulation Pipes Larger Than 4 In. 1 in. IX in. 2 in. 2M in. 3 in. 3X in. Pipes 2 In. to 4 In. 1 in. 1 in. IX in. 2 in. 2X in. . 3 in. Pipes X in. to IX In. 1 in. 1 in. 1 in. IX in. 2 in. 2 in. . 8l'0wS1ilDPiKi?!je?ated?'-lWOOrajOr.KIP"-`d `O > . ln this table, and covered with a waterproof juck-.it. jju.i.y inj amt i to a thicanjss ; in. greater than 1954 Guide Pipe Insulation 639 CHAPTER 28 638 example. In using the chart, start with the scale'at the left bottom margin representipg the given number of hours of operation per year; then proceed vertically to the line representing the given value of heat'; . thence horizontally to the right, to the line representing the given tem perature difference; thence vertically to the line representing the con ductivity of the given material; thence horizontally'to the left, to the line representing the given discount on that material; thence vertically to the curve representing the required percent return on the investment; thence horizontally to the right, to the curve representing the given pipe size; thence vertically to the scale at the top right margin where the eco nomical thickness may be read off directly. . A rapid method for determining the economical thickness of insulation by use of tables has been published.2 `1 UNDERGROUND PIPE INSULATION Underground steam distribution lines are carried in protective struc tures of various types, sizes and shapes (see Chapter 29). Detailed data Table 11. Thickness of Loose Insulation fob Use as Fill in -- "Unbebground Conduit Systems Minimum Thickness op Insulation in Inches Pressure . Psio ob Condition Temperature Fahrenheit Degrees Steam Lines Return Lines Pipes Less Pipes 4 In. Pipes Larger Pipes Less Pipes 4 In. than 4 In. to 10 In. than 12 In: 'than 4 In. - and Larger Hot Water, or 0 to 25 212 to 267 ij4 2 234 ik IK 25 to 125 267 to 352 2 234 3 IK 134 Above 125,or superheat 352 to 500 2-34 3 334 IK IK Minimum Between Steam Return i IK IK on commonly used forms of tunnels and conduit systems, have been pub lished by the National District Heating Association.'- Pipes in tunnels are covered with sectional insulation to provide maxi mum thermal efficiency, and are also finished with good mechanical pro tection 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 firmly secure the covering with corrosion resistant wire, then sew on a wire-inserted asbestos fabric jacket with .yfire. This jacket is porous. The 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 i insulation; however, the more usual practice is to fill the entire section of the conduit around the pipes with high quality, loose insulating material. The insulation must be kept dry at all times, and for this purpose effective waterproofing membranes enclose 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 fo determine accurately due to the many variables which have to be considered. As a result of theories4 previously developed, together with other experimental data which have been presented, the usual endeavor 640 CHAPTER 28 1954 Guide is to secure not less than 90 percent efficiency for underground piping. Table 11 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 standard conduit sizes, are primary controlling factors in the amount and thickness of insulation for use. - When sectional insulation is applied to lines in tunnels or conduits, usual practice is to apply the most efficient materials in. less in thick ness 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 temperature is substituted for air temperature in determining the teinperature difference for use with the chart when applying it for underground pipe line estimates. . REFERENCES 1 Heat Loss from Copper Piping, by R. H. Heilman (Seating, Piping and Air Con ditioning, September, 1933, p. 458). 1 Rapid Method of Determining the Economical Thickness of Pipe Insulation, by Utley W. Smith (A.S.H.V.E. Journal Section, Heating, Piping and Air Condi tioning, October 1947, p. 118). ' District Heating Handbook of the National District Healing Association, Third Edition, 1951. - 4 Theory of Heat Losses from Pipes Buried in the Ground, by J. R. Allen (A.S.H.V.E. Transactions, Vol. 26,1920, p. 335). BIBLIOGRAPHY Heat Emission from Iron and Copper Pipe, by F. C- Houghten and Carl Gutberlet (A.S.H.V.E. transactions, Vpl. 39, i938, p. 97). ' Heat Transmission from Surfaces (Philip Carey Mfg. Co., Bulletin 102-A). Surface Heat Transmission, by R. H. Heilman (Mechanical Engineering, Sec. 1, MaPyip1i9n2g9, Hpa.n3d5b5o)o. k, by S'. Crocker (McGraw-Hill Book Co., Fourth Ed, ition, 1945). Insulation Handbook, by P. Swain (Power, Vol. 94, Nos. 2, 3, 5, 7, and 9, 1950). How to Insulate Equipment, by U. W. Smith (Plant Engineering, Vol. 1, No. 2, DeHc.ea19t 4T7,rapn. s3f2e)r. Through Thick Insulation on Cylindrical Enclosures, by T. S. Nickerson and G. M. Dusinberre (ASME Transactions, Vol. 70, No. 8, November 194A8p, pp.lie9d03H).eat Transmission, by Herman J. Stoever (McGraw-Hill Book Co., 1941), CHAPTER 29 DISTRICT HEATING Steam Distribution Piping, Pipe Sizes, Conduits for Piping, Pipe Tunnels, Overhead Distribution, Inside Piping, Metering, Steam Requirements, Rates THE term district heating refers to the heating of several buildings from a central plant as in the heating of portions of cities, or to the heating of groups of buildings as in institutions and factories. It is usually prefer able, in a group of industrial or institutional buildings, that they be heated from a central plant rather than by individual plants. Fuel can generally be burned more efficiently, less labor is required, and often a central plant is cheaper to install. Those phases of district heating which frequently fall within the province of the heating engineer are outlined here, with data and information for solving incidental problems in connection with institutions and factories. Soine data are included to cover the piping peculiar to heat ing systems which'are to be supplied with purchased steam. A complete district heating installation should not be attempted without a thorough study of the entire problem by men competent and experienced in that industry. . Air Conditioning. In many cases steam from district heating mains can be used for air conditioning. There are three types of refrigeration machines which use steam as a source of energy. They are: (1) steamdriven compression machines, mostly turbine-driven; (2) steam jet ma chines; and (3) absorption machines. The .method of using the steam for the cooling unit and for closed absorption systems is described in Chapter 37. The methods used in district heating work for the distribution of steam are applicable to any problem involving the supply of steam to a group of buildings. The first step is to establish the route of the pipes, and in this mgaardttienrg, siti.nce the local conditions control the layout, little can be said re Having established the route of the pipes, the next step is to calculate the pipe sizes. 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 increases, will be transmitted without exceeding this pressure drop. The steam velocity is therefore almost disregarded and may reach a very high figure. Velocities of 35,000 fpm are not considered high. By the use of this method the pipe sizes are kept to a minimum with conse quent savings in investment. The steam flowing through any section of the piping can be computed from a study of the requirements of the several buildings served. In general, a condensation rate of 0.25 lb per (hr) (sq ft of equivalent direct radiation) is a safe figure. This allows for line condensation which, howeyer, is a small part of the total at times of maximum load. Miscellaneous 641 642 CHAPTER 29 1954 Guide District Heating 643 steam requirements such as laundry, cooking, or process, should be indi neath the conduit. The tile underdrain should be carried to the sewer or vidually calculated. The steam requirements for water heating should some other drainage point. Manholes are required at intervals for access i i i S'i be taken into account, but in most types of buildings this load will be relatively small compared with the heating load, and will seldom occur at the time of the heating peak. Unusual features, such as large heaters for swimming pools, should not be overlooked. The pressure at which the steam is to be distributed will depend upon (1) boiler pressure, (2) whether exhaust or live steam, and (3) pressure requirements of apparatus to be served. If steam has been passed through to valves, traps, and some types of expansion joints. . -' Where steam and return piping are installed in the same conduit, the return piping usually follows the same grade as the steam piping. In' general, the condensation is pumped back under pressure. Where it is possible to use basement or sub-sidewalk space for the dis tribution piping, the cost of installation and maintenance is greatly reduced. electrical generating units, the pressure will be considerably lower than if live steam, direct from the boilers, is used. The advantages of low pressure distribution (2 to 30 psig) are: (1) smaller heat loss per square foot of pipe surface; (2) less trouble with traps and valves; (3) simpler problems in pressure reduction at the buildings; and (4) general reduction in maintenance costs. With distribution pressures not exceeding 40 psig, there is little danger even if the full distribution pres sure should build up in the radiators through the faulty operation of a reducing valve; but with pressures higher than 50 psig, a second reducing valve or some form of emergency relief is usually desirable to prevent ex >! i1}t; cessive pressures in the radiators. ' '! : The advantages of high pressure distribution are: (1) smaller pipe sizes; (2) 'greater adaptability of the steam to various operations other than building heating; and (3) wider flexibility in allowance for maximum pres sure drop and ability to serve equipment requiring higher pressures. : li; Frequently the different kinds of apparatus which must be served require various minimum pressures. Kitchen equipment requires from 5 to 15 psig, the higher pressures being necessary for apparatus in which water is boiled, such as stock kettles and coffee urns. An increased amount of heating surface, which is easily obtained in some kinds of apparatus, re sults in quicker and more satisfactory operation at low pressures. For laundry equipment, particularly the mangle, a pressure of 100 psig is usually demanded, although 30 psig is sufficient if the flat work ironer is equipped with a large number of rolls, and if a slower rate of operation is permissible. Pressing machines and hospital sterilizers require about 50 psig. Where pressures are not as high as desired, higher pressures can be obtained by means of a steam compressor. Important points in laying out underground conduits are: 1. The depth of the buried conduit should be kept at a minimum. Excavation costs are a large factor in the total cost. 2. An expansion joint, offset, or bend should be placed between each two anchors- Advantage should be taken of the flexibility of piping to absorb expansion wherever possible. Information on provisions for expansion will be found in Chapter 27. 3. A proper hydrostatic test should be made on the assembled line before the Fio. 1. CoNSTBucno.v Details or Conduits Commonly Used Pipe Sizes. The lengths of pipe, steam quantities, and initial and terminal pressures having been chosen, the pipe sizes can readily be cal culated by means of Babcock's pressure drop formula given in Table 2 of Chapter 21. insulation and the top of the conduit are applied. The hydrostatic test pressure t! I! should be one and one-half times the maximum service pressure, and it should be held for a period of at least two hours without evidence of leakage. Conduits for steam CpiOpeNsDUbuITriSedFuOnRdePrgIProIuNnGd should be reasonably waterproof, able to withstand earth loads and to take care of the expansion Since it is difficult to make a concrete or masonry conduit absolutely water-tight, provision should be made for some seepage. The pipe should ^contraction of the piping without strain or stress on the couplings, or without affecting the insulation or conduit. Expansion of the piping must be protected by a waterproof jacket over the insulation, and the seepag so uareful|y controlled by means of anchors and expansion joints or bends drained from the inside of the conduit. Underdrainage of the conduit is k k Me pipes can never come in contact with the conduit. Anchors generally provided for by a tile drain laid in crushed stone or gravel under "e anchor fittings or U-shaped steel straps which partially encircle the neath the conduit. The tile underdrain should be carried to the sewer o an<^ are firmiy bolted to a short length of structural or cast steel set in . nerete. In general, cast steel is preferable to structural steel. 644 CHAPTER 29 1054 Guide There are many types of conduits, some of which are manufactured products and some of which are built in the field. Some of the more com mon forms are illustrated in Fig. 1. The conduit (A) is of a wood casing construction which has been widely used in the past. The wood casing is segmented, lined with tin, and bound with wire. The outside of the conduit is coated with asphaltum. It is not suitable for high temperatures or poorly drained soils. In Fig. 1 (B), (C), (D), (H) and (I) are patented forms of conduits. The insulation is sometimes a loose filler packed into the conduit. Con- Fiq. 2. Connections fob Reducing Valve Without Bt-pass Heating main Bypass vah Service valve Balance pipe Pipe to connect into steam mam not ress than }0 teet from reducing valve, i! possible Fig. 3. Connections fob Reducing Valve with Bt-pass duits (H) and (I) are prefabricated. Both of these conduits are enclosed in metal jackets. At (C) and (E) are shown two tile conduits using sectional insulation-.:. In these particular designs the space surrounding the pipe is filled partiallyor wholly with a loose insulating material. The addition of this loose in sulating material to the sectional insulation is, of course, optional and is justified only where high pressure steam is used. ' (E) and (F) are conduits used by two district heating companies, and, have the advantage of being constructed of common materials. ", Conduit (G) is of cast-iron construction, assembled with lead joints and is water-tight, if properly laid. It is obviously expensive and is justified only in exceptional cases. ' ,. There are, in addition to those mentioned, several conduits which use- an insulating concrete as a pipe insulation. The insulating effect of the- concrete is obtained by admixture of an insulating material with cement;, District Heating 645 PIPE TUNNELS Where steam beating lines are installed in tunnels large enough to pro vide walking space, the pipes are supported by means of hangers or roller frames on brackets or frame racks at the side or sides of the,tunnel. The pipes are insulated with sectional pipe insulation over which is placed a sewed-on, painted canvas jacket or a jacket of asphalt-saturated asbestos water-proofing felt. The tunnel itself is usually built of concrete or brick, and water-proofed on the outside with membrane water-proofing. Because of their relatively high first cost as compared with smaller con duits, walking tunnels are sometimes omitted along heating lines, unless they are required to accommodate miscellaneous other services, or provide underground passage between buildings. OVERHEAD DISTRIBUTION In some industrial and institutional applications, the distribution piping may be installed, entirely or in part, above ground. This method of con- Pressure reducing valve At least 12 feet of pipe Customer's pressure reducing valve Customer's control valve Note All valves, fittings, and Customer's work traps up to and Including . starts here customer's control valve to ' bo at toast equal to'Amor)* lean Standard 160 lb. S. S. P Plpa to be Schcd. ulo 40. . Continuousflow type .. > . float trap Fig. 4. Steam Supply Connection when Using Two Reducing Valves , struction has the advantage of requiring no excavation and being easily maintained. INSIDE PIPING Figs. 2 and 3 show typical service connections used for low pressure steam service. Fig. 2 shows installation of a reducing valve without a by-pass, which is usually omitted in the case of smaller size valves. Fig. 3 illustrates the use of a reducing valve, with a by-pass which is gen erally provided for larger installations. This latter construction permits the operation of the line in case of failure in the reducing valve. In the smaller sizes, the reducing valve can be removed, a filler installed, and the house valve used to throttle the flow of steam until repairs are made. Pig. 4 shows a typical installation used for high pressure steam service.1 The first reducing valve effects the initial pressure reduction. The second reducing valve reduces the steam pressure to that required. , In a heating system the 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 provide proper venting of non-eondensable gases. (See Chapter 43, Corrosion.) . Most district heating companies enforce certain regulations regarding he consumer's installation, partly to safeguard their own interests, but lCode for Pressure Piping, B31-1, 1942, American Standards Association, Paragraph 408, p. H5. 646 CHAPTER 29 1954 Guide principally to insure satisfactory and economical service to the consumer. There are certain fundamental principles that should be followed in the design of a building heating system which is to be supplied from street mains.. Although some of these apply to any building, they have been demonstrated to be especially important when steam is purchased. 1. Provision should be made for conveniently shutting off the steam supply at night and at other times when heat is not needed. It has been thoroughly demonstrated that a considerable amount of heat can be saved by shutting off steam at night. Although there is, in some cases, an increased consumption of heat when steam is again turned on in the morning, there is a large net saving which may be explained by the fact that the lower inside temperature maintained during the night obviously results in lower heat loss from the building, and less heat need therefore be supplied. Steam can be entirely shut off at night in most buildings, even in very cold weather, without endangering plumbing. It is necessary, however, to have an ample amount District Heating 647 Because of the lack of coincidence between the heating system load and the hot water demand, a greater amount of beat can be. extracted from the condensate if storage capacity is provided for the preheated water. Frequently, a type of econ omizer is used in which the coils are submerged in a storage tank. , J. Heat supply should be graduated according to variations in the outside temperature.1 The maximum in economical operation and satisfactory heating can only be ob- 1 tained by the use of automatic temperature control (See Chapter 39). METERING "\V The perfection of fluid meters has contributed as much .to the advance1ment of district heating as any other one thing. Meters are classified into two groups: Condensate Meters and Rate of Flow Meters. - . . .. Condensate Meters The one type of quantity meter used is the condensate meter, which may be of the tilting bucket or revolving drum type. The condensate meter is a popular type for use on small and medium of heating surface so that the building can be quickly warmed in the morning. Where the hours of occupancy differ in various parts of the building, it- is good practice1# install separate supply pipes to the different parts. For example, in an office build ing with stores or restaurants on the first floor which are open in the evening, a sepa rate main supplying the first floor will permit the steam to be shut off from the re mainder of the building in the late afternoon. The division of the building into zones, each with a separately controlled heat supply, is sometimes desirable,1asut permits the heat to be adjusted according to variations in sunshine and wind.'jon !. Residual heat in the condensate should be salvaged. . _ This heat may be salvaged by means of a cooling coil, or as is more freqireatb done, by a water heating economizer (see Fig. 5) which preheats the hot water supply to the building. r! The condensate from the heating system, after leaving the trap, passes through the economizer. The supply to the hot water heater passes through the econoihizer, absorbing heat from the condensate. If the hot water system in the building i. the recirculating type, the recirculating connection should be tied in between'^ economizer and the water heater proper, not at the economizer inlet. becauseStn recirculated hot water is itself at a high temperature. Fio. 6. Gravity Installation fob Condensation Meteb Using Vented Receivers sized installations, where all the condensate can be-brought to a common point for metering purposes. Its simplicity of design, ease in testing, ac curacy at all loads, low cost, and adaptability to low pressure distribution have made it standard equipment with many heating companies. Condensate meters should not be operated under pressure; they are made for either gravity or vacuum installations. Where bucket traps are used, a vented receiver "is essential ahead of the meter. Where continuous flpw traps are used, a vented receiver is not necessary, but is desirable. 'ig. 6 illustrates a gravity condensate meter installation using a vented receiver. Rate of Flow or Flow Meters Flow meters used for district heating work are of three types: Area Meters, Head Meters and Velocity Meters. (See Chapter 4, Fluid Flow.) Area meters are those in the operation of which a variation in the cross motion of stream, under constant head, is used as an indication of the rate w flow. A tapered plug is suspended in an orifice and moves axially with the flow, which is vertically upward. The weight of the plug provides a definite pressure differential, and the plug floats at such a height as will Provide enough orifice area to pass the flow at the pressure difference. The rs= i i. ' 'if Pc movement of the plug is transmitted by means of a lever to a pencil or marker which records the flow on a graduated strip chart. ' .. Head meters are those in which the stream of fluid creates a difference' of pressure, or differential head. This head is created by an orifice, Venturi > tube, flow nozzle, or, Pitot tube, and will depend upon the velocity and. density of the fluid. The secondary element must contain a differential pressure gage, which will translate the pressure difference into rate of flow or total flow. This mechanism may be either mechanical or electrical. The electric flow meter has the advantage of being able to locate the in struments at some distance from the primary element. . : Fig. 7 is a typical example of an orifice-type meter installation. A few general points to be considered in installing a meter of this type are: (1) Fig. 7. Obifice Meter Steam Supply Connection it is desirable to place the differential medium in a horizontal pipe in prefer-ence to a vertical one, where either location is available; (2) reservoirs should always be on the same level and installed in accordance with the instructions of the meter company; (3) the meter body should be placed at a lower level than that of the pressure differential medium--special instructions are furnished where the meter body is above; (4) meter piping should be kept free from leaks; (5) sludge should not be permitted to collect in the meter body; (6) the meter body and meter piping should be kept above freezing temperatures; (7) it is best not to connect a meter body to more than one service; (8) special instructions are furnished;for metering a turbulent or pulsating flow. . .V Velocity meters are those in which the primary element is some device that is kept in continual rotation by the linear motion of the stream. The secondary element is, essentially, a revolution counter. The primary and secondary elements are combined into one unit. ' For steam metering, the shunt meter is an example of the velocity type- This unit is connected directly in 2, 3, and 4-in. pipe lines. Larger-size mains are metered by installing a 2-in. meter in a by-pass with a restricting orifice in the main line. 1 District Heating . ,: . 649 Selection of Meter In selecting a meter for a particular installation, the number of different makes and types of meters suitable for the job is usually limited by one or more of the following considerations: (I) its use in a new or an old installation; (2) method to be used in charging for the service; (3) location of the meter; (4) large or small quantity to be measured; (5) temporary or permanent installation; (6) cleanliness of the fluid to be measured; (7) temperature of the fluid to be measured; (8) accuracy expected; (9) nature of flow, i.e., turbulent, pulsating, or steady; (10) cost: (a) purchase price, (b) installation cost, (c) calibration cost, (d) maintenance cost; (11) servicing facilities of the manufacturer; (12) pressure at which fluid is to be metered; (13) type of record desired as to indicating, recording or totalizing; (14) stocking of repair parts; (15) use of open jets where steam is to be metered; (16) metering to be done by one meter or by a combina tion of meters; (17) use as a check meter; (18) its facilities for deter mining or recording information other than flow; (19) whether or not the condensate can be returned to a central point. .Buildings, per Cu Ft of Volume* Type op Building Consumption, Lb/Yb/Cu Ft Consumption Lb/Yr/Cu Ft/100 F deq Temp. Kiss op Wateb ' Hotel Residence Club . Apartment House Department Store Office ' Theatre . Forking 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 fourteen district heating companies from metered consumptions. Building volume 8 approximate gross volume- . .' STEAM REQUIREMENTS Methods of estimating steam requirements for heating various types of buildings are given in Chapter 18. : Table 7 in Chapter 18 represents information obtained from all sections of the United States, and the group of buildings from which the informa tion was taken represents a cross-section of all types of heating systems. Steam requirements for process equipment in kitchens, laundries, and hospitals are given in Table 1. Average annual steam requirements for Water heating for various types of buildings are given in Table 2. Water requirements for various uses are given in Chapter 49, Water Services. Additional data on steam requirements of various types of buildings in a number of cities may be found in the Handbook of the National District Heating Association. '- ivnij&o Fundamentally, district heating rates are based upon the same princiPJes as those recognized in the electric light and power industry, the main a reasonable return on the investment. However, there are other requirements to be met: the rate for each class of service should be ased upon the cost to the utility company of the service supplied, and 650 CHAPTER 29 1954 Guide --EQr-U--IP--MrErNr:T "Tabus 2. Unit Steam Consumption of Process^ 1 Kitchen Appliances (exclusive op WATER BEATING) Consumption, . Lu pee He ' Pressure, ' PSIG Stock and vegetable kettlee-(per 5 gal) Vegetable steamers (per compartment) Steam tables (per sq ft) Bain-Maries (per sq ft) Coffee urns (per gal) ' . . . - Water urns (per gal) .. Soup warmers (30 X 30 X 28 in.) . Egg boilers (3 compartments) ' . Clam, lobster, and potato steamers (per compartment) Oyster pots Plate and cup warmers (per 20 cu ft) Food-warming ovens (per 20 cu ft) Silver burnisher and washers Dishwashers (per tray) , - 20.0 40.0 1.7 3.4 . 3.4 ` 5.0 . 100.0 18.0 40.0 18.0 35.0 35.0 69.0 60.0 7-20 7-20 7-20 7-20 7-20 7-20 7-20 7-20 7-20 7-20 7-20 7-20 7-20 7-20. Launpbt Equipment Tumblers 40 X 94 in. 30 X 36 in. Washers, (per gal water heated) Flatwork ironers, 100 to 120 in. chest type (per roll) 50 to 100 in. cylinder type (per machine) Standard presses Large shirt body presses Cuff and neckband presses Sleevera Steam-electric irons Woolen pressing machines Large--electric vacuum Small--electric vacuum Large--steam vacuum Small--steam vacuum Feather cleaning and sterilizing 15 piiiowB per hr Hospital Equipment Sterilisers, for bottles or pasteurization (per bottle) Sterilizers, for water, (per gal) Sterilizers, for instruments and utensils, 8 X 9 X 18 in., water depth 3)4 in. 9 X 10 X 20 in., water depth 3)4 in. 10 K 12 X 22 in., water depth 4 in. 12 X 16 X 24 in., water depth 4 in. 10 X 12 X 36 in., water depth 4 in. 16 X 16 X 20 in., water depth 10 in. 20 X 20 X 24 in., water depth 24 in. 360 225 1 60 60-120 105 190 15 12 8 25 12 35 20 175 \ 12 27 30 39 60 66 92 144 100 100 15-100 100 100 100 too 100 100 100 65 65 65 65 100 40 40 40 40 40 40 40. 40 40 Sterilizers, for instruments @ 240-250 F, 12 X 20 in. 14 X 22 in. 16 X 24 in. 40 48 40 60 40 72 District Heating 651 Table 2. Unit,Steam Consumption of Process Equipment (Concluded). Hospital Equipment (continued) Consumption, Lb peb Hr Pressure, PSIG Sterilizers, for surgical supplies . 10 X 20 in. 10 40 12 X 20 in. 22 40 . 14 X 22 in. 28 40 16X^4 in. . 38 40 16 X .36 in. . 54 40 20 X 28 in. 20 X 36 in. 20 X 48 in. 20 X 60 in. 60 40 78 40 98 40 124 40 Sterilizers, (autoclave) (240-250 F) 15.5 X 24 in. 17.5X26 in. 21.5 X 30 in. 24 X 36 in. ' ' 24 40 32 40 40 40 42 40 Disinfector, mattress . 30 X 42 X 84 in. 42 60 X 66 X 108 in. Blanket warmers -------- -------- - 318 18 X 24 X 72 in. .4 35-60 35-60 35-60 * From District Heating Handbook {National District Heating Association, Third Edition, 1951). & The above figures represent approximate operating conditions after warm-up period. upon, the value of the service to the consumer, and it must be between . these two limits. District heating rates should be designed to produce a sufficient return on the investment regardless of weather conditions, al though existing rate schedules do not always conform to this principle Lastly, the rate schedule must be reasonably simple and understandable. Glossary of Rate Terms Load Factor. The ratio, in percent, of the average hourly load to the maximum hourly load. This is usually based on a one-year period, but may be applied to any specified period. Demand Factor. The relation between the connected radiator surface, or required radiator surface, and the demand of the particular installation. It varies from 0.25 to 0.3 lb per (hr) (sq ft of surface). Diversity Factor. The ratio of the sum of the individual demands of a number of buildings to the actual composite demand of the group. Types of Rates The various types of rates to be found in use in district heating systems are: 1- Slraighl-Line Meier Rate. The price charged per unit is constant, and the con sumer pays in direct proportion to his consumption without considering the dif ference in costs of supplying the individual customers. 2. Block Meier Rate. The pounds of steam consumed by a customer are divided into blocks of thousands of pounds each, and lower rates are charged for each suc cessive block consumed. This type of charge predominates in steam heating rate schedules, having the advantage of proportioning the bill according to the consump tion and the cost of service. It has the disadvantage of not discriminating between 652 CHAPTER 29 1954 Guide customers having a high load factor (relatively low demand), and those having a low load factor (relatively high demand). The utility company must maintain sufficient capacity to serve the high demand customers, and the cost of the increased plant investment is divided equally among the users, so the high demand customers are benefited at the expense of the others. 3. Demand Rates. These refer to any method of charge based on a measured maximum load during a specified period of time. The flat demand rate is usually expressed in dollars per thousand pounds of demand per month or per annum. It is based on the size of a customer's installation, and is seldom used except where a meter is not practicable. The Wright demand rale is similar in calculation to the block rate, except that it is expressed in terms of hours' use of the maximum demand. It is seldom used, but forms the basis for other forms of rates. The Hopkinson demand rate is divided into two elements: (a) A charge based upon the demand, either estimated or measured. (b) A charge based upon the amount of steam consumed. This rate may be modified by dividing the quantities of steam demanded and con- sinned into blocks charged for at different rates. The Doherty rate is divided into three elements: , ., (a) A charge based upon demand. (b) A charge based upon steam consumed. (c) A customer charge. In the Hopkinson rate, the last two elements are combined into one element. Demand rates are comparatively new and are not yet widely used. While they are equitable and competitive, they are difficult for the average layman to understand. They are of benefit to utility companies and to consumers because the investment and operating costs can be divided, to suit the particular circumstances, into demand, customer, and consumption groups through the use of some modification of the Hbpkinson rate. De mand rates are an advantage to the customer in that the use of such a rate reduces the rate per thousand pounds to the long-hour user. ' Fuel Price Surcharge. It is usually desirable to establish a rate upon a specified basic cost of fuel to the utility company. Where there are wide variations in the price of fuel, it is also desirable to add a definite charge per thousand pounds of steam sold for each increment of increase in the price of fuel. This surcharge automatically compensates for the variations without necessitating frequent changing of the whole rate structure. " Some utility companies include a labor surcharge as well as a coal sur charge. . -I.'- CHAPTER 30 CENTRAL SYSTEMS FOR AIR CONDITIONING Features of Systems, Zoning, Humidity Control, Cooling Load, Heating Load, Air Quantity and Effectual Temperature.Difference, Low and High Pressure Induction Convectors, Evaporative Cooling, Precooling, Sensible Cooling with Unwetted Coils, Run-Around System, Selection of Type of System, Location of Apparatus, Design Procedure THE term, central, applied to an air conditioning system implies that the equipment such as fans, coils, filters and their encasement are designed for assembly in the field rather than in a factory as a unit. As a central system usually serves several different'rooms, individual con trols are required for each room. FEATURES OF CENTRAL SYSTEMS One advantage of a central air supply system is that one apparatus serving many rooms may involve a lower investment 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, 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 factoryassembled equipment. Central air conditioning systems usually are connected by ducts with the various rooms served, and preferably have exhaust fans that may effect complete removal and disposal of any desired proportion of the air. The exhaust fan may return air to the supply system for recirculation, as a measure of economy of fuel or refrigeration. Central air conditioning systems are served by heating and refrigerat ing equipment which may be located at some distance from the air supply apparatus, and which may serve one or more central air supply systems. Year-Round Air Supply System Fig. 1 is a plan of a year-round air supply system. Outside air may enter from the left at A, desirably, from an intake on the side of the build}Pg least exposed to solar heat, and not close to the ground or to a sunheated or dust-gathering roof. The damper B for proportioning the volume f outside air, is interlocked with the return air damper C in such manner mat as the outside air volume increases the return air volume decreases. The return air duct D, shown diagrammatically, comes from the exhaust fan. All the air, it will be observed, must pass through the filters E, and there is ample room on both the inlet and outlet sides of the filters for servicing them. The filters may be of mechanically cleaned type, of replaceable cell type, or may be electronic, as described in Chapter 34. The cleaned air passes to the equipment that changes its temperature and humidity. Except in very warm climates, a heating or tempering coil F is required to warm the air to a temperature above freezing. Usu- 653 654 CHAPTER 30 1954 Guide ally, the heat is supplied by means of hot water or steam. During many hours of most days it is practicable to recirculate enough of the air so that the air drawn from outside, after mixing with the relatively warm return. air, will not be cold enough to freeze the water in the humidifier. Upon leaving the tempering coil, the air enters the humidifier G. This may be a spray of warmed water, circulated by a small pump from a water tank under the spray chamber, or may be other means of supplying water vapor. The supply of moisture must be under automatic and very reliable control. Following the humidifier a heater I is required, for con trolling the temperature of the air entering the supply fan. The second group of heat transfer devices in a year-round system includes an air cooling component H, for use in warm weather. Its sur face may be chilled by direct expansion of an approved refrigerant within its tubes, or the surface may be cooled by a pump-circulated liquid such Central Systems for Air Conditioning 655 trol is attainable merely by proportioning the flow of air to each room1, 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 to warm the air to suit the occupants. The air, for example, leaving the fan that serves several rooms, may be cooled before entering the fan, to the condition favorable for one room, and the air for each other room may be reheated by the branch duct coil to the required temperature. It is also possible to circulate a heat ab sorbing 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. In Fig. 1 such coils J are indicated in the three branch ducts leaving the supply fan. When heat transfer devices are placed in branch ducts for improved temperature control, mechanically circulated water gives excellent results as a heat Fig. 1. Arrangement op Equipment for Year-Round Air Supply System as water or brine. The coil must be sufficiently cold to cool the sum mer air to a temperature below the existing dew-point, and may be ex pected to be wetted constantly by the moisture condensed from the air. A water-tight drainage tank must be installed under the cooling coil and should extend for a distance toward the fan. Water should be drained by means of a trapped waste through a vented air-break. The second group of heat transfer devices also includes an air-heating component (reheater) similar to the tempering coil and capable of warming the chilled, saturated air leaving the cooling surface, to a temperature suffi ciently high to prevent complaint of drafts when the air enters the rooms. ZONING AND ZONE CONTROL It is apparent that while an 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 Prl> 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 temperature, hu midity and air movement in various rooms or zones. A measure of con-, Fig. 2. Alternate Arrangement of Equipment for Controlling Air Condition in Central Air Supply System 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 side of each relatively small supply fan. The designer must remember that the various supply fans will compete with each other for air, against the resistance interposed by the filters, cils, etc., that are used in common under such circumstances, and con sequently, unless the fans are of backward-curved blade, non-overloading type, they may alternate in carrying more than their share of the air, and thereby cause the air distribution to be chaotic and unsatisfactory. Another method of controlling temperature in various rooms served uy a central air supply 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 uehver 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 chambers many separate ducts, one of which is shown, each with a houble-blade mixing damper, may convey the air to the various rooms. Ulft . mhaiiVx--*irnwogr dampers, one------------------------' v/A-i.vy voif1 wtvhijijvcuh iios oshuouwwnii,, aarlee AinlltWerjrlioUcCkKeeUd SsOo t.h.a.t aLsS ltlh-fie6 PP^r one closes, the lower one opens; selecting between them, air in the inquired quantity from either the warmer chamber A or the cooler one B. 656 CHAPTER 30 1954 Guide 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 hot always sufficiently precise to meet requirements, since the untreated air delivered through the upper coil may be so high in relative humidity that it cannot sufficiently compensate for the nearly saturated air leaving the lower coil. A reheater could be placed if desired, to the right of the lower coil to bring the air in the iower 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. ............ Another method of attaining temperature control in individual 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 Fia 3 Arrangement for Individual Room Temperature Control with ' .. . Central Air Supply System . 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, 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 air supply, duct is ,qeT livered into the room, the spent air outlet is throttled in proportion. , Jn 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 used for supplying the rooms of one brientation of each story. In other cases the booster fans serve only single offices, and therefore are small enough to be concealed above ceilings along: side 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 objectionable. In such cases the general recircu lation arrangements of Fig. 1 may be omitted, and heat transfer cons located in the ducts may be used. In some cases where general recircQ" lation is not acceptable, as for all the rooms in an entire building, use of the local circulation of Fig. 3 may solve the problem. '. , Central Systems for Air Conditioning 657 HUMIDITY CONTROL In winter, room relative humidities in excess of 30 percent are seldom required in a system designed for comfort conditioning only, and a low saturating efficiency may be desirable, or even necessary, especially if the same volume of air is handled as in summer. With a spray type dehu midifier the main sprays may be 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 spray 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 avail able, to introduce steam directly into the air stream to produce the desired dew-point temperature of supply air. However,, the steam must be ex ceptionally 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. Infiltration 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. ' For summer operation and significance of apparatus dew-point see Chap ter 13, Cooling Load. ' COOLING LOAD The method of determining the cooling load for a conditioned 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 these peaks and the avoidance of pyramiding 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. A large difference in the time-incidence of the peaks between 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 gain forms a fair share of the cooling load, the times 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 take full advantage of this con dition or of similar conditions of non-simultaneous peaks, and will result in a lower total load and in savings in equipment. A factor similar in effect and closely related to the non-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 attending 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 poly large enough to handle the average maximum. If a system employ,ng zone recirculating fans and a single central fan and dehumidifier were H l saving would be reflected in the capacity of the central fan and aehurrudifier. Another example of this diversity is found in an office 658 CHAPTER 30 1954 Guide building having restaurants and stores of certain types in the first story and basement. 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 radiation 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 inside temperatures to offset the radiant energy. Buildings have considerable heat storage capacity which can often be utilized to great advantage, and which has more than once provided an unexpected safety factor. If a space is kept below the design inside tem perature for some time, the interior walls, floors, furniture and fixtures begin to assume the temperature of the space. Where the time is suf ficient the entire mass, rather than merely its surface, may reach the room temperature. Thus, when a space has been precooled below the design maximum temperature for a period of time prior to the advent of the peak load, and the heat gain begins to increase the 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 accord ingly. However, unless very accurate data with regard to the mass, sur face, 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. Where air conditioning supply and return ducts pass through uncon ditioned 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 allow ance should be made for this heat gain and included in the heat estimate so that air can be supplied at a temperature low enough to offset the rise caused by this heat gain (see Chapter 32). There will also be some heat gain to Hie air in ducts passing through conditioned spaces, but since a cooling effect is produced in the space through which the duct passes, this is not a loss and usually can be compensated for by adjustment of air quantities between the various spaces. HEATING LOAD Methods of calculating the heating load are shown in Chapter 12. Many of the factors outlined previously under Cooling Load, such as zoning, non-simultaneous peaks, and diversity, apply in the reverse man ner 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 economy of opera tion more than from a capacity of equipment standpoint. It is not only necessary to heat a building or space to its design condition? when there is but the merest fraction of normal occupancy, and when there are prac tically no lights, internal heat, or solar radiation, but it is also necessary to provide capacity to heat the building quickly when sudden cold follows relatively warm weather, as may occur after a week-end or holiday shut down. However, in normal operation during week-ends and holidays, buildings are usually kept at a holding temperature to prevent the freezing of services. In many cases, less fuel is required to continue operation of the heating plant at a near-normal rate and maintain the building r Central Systems for Air Conditioning 659 space at a temperature of 50 to 65 F at such times, than to shut the sys tem 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 EFFECTUAL TEMPERATURE DIFFERENCE The difference between the room air temperature and the supply air temperature at the outlet to the room is known as the effectual tempera ture difference. In the theoretical case 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 effec tual temperature difference 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 than is indicated 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 effectual temperature difference. Thus if the difference between the room tem perature and the apparatus dew-point indicates that 10,000 cfm at 30 deg below room temperature will be required 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 an effectual temperature dif ference 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. Low effectual temperature dif ferences may be required for this reason. While the use of a high effectual temperature difference results in a saving in initial cost of fans and ducts, aj\d in the operating cost of fans, this difference should be carefully con sidered. If the sensible heat load of a space is subjected to substantial variations, low effectual temperature differences should be considered, since systems employing low effectual temperature differences require less precision in controls. Reduction of air quantity by slowing down the fans for the winter season, and increasing the temperature difference, often is feasible. A saving in fan power can thus be effected, provided the air distribution remains adequate. Extremes should be avoided in all cases. For summer air conditioning, ow supply air temperatures result in larger heat gains to the air passing 660 CHAPTER 30 1954 Guide through the ducts, as well as in poor control. Too high a supply air tem perature may result in excessive initial and operating costs. Suggested limits for the effectual temperature difference are from 12 to 20 deg. the actual selection being based on the requirements of the particular 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 31 for further discussion of the most satisfactory design difference between the entering air temperature and volume in relation to the desired room condition. Fig. 4. Induction Unit (Low Pressure Type) FiQ- 5. Induction-Unit (High Pressure Type) 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 mixture is discharged into the room through* grille at the top of the convector. Heating coils are located in the second ary air stream. The output is controlled either by manually or auto matically throttling the air jet. Heat may be supplied to the coil in summer as well as in winter. These induction convectors present several advantages. Since the secondary air stream is thoroughly mixed with the high velocity low temperature air stream before leaving the discharge outlet of the device, the resultant temperature of the mixture is satis factory 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. Ah air conditioning system without induction convectors may require in-,, stallation 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- Central Systems for Air Conditioning 661 maintain, by thermal circulation, a reasonable temperature when the pri mary air supply system is shut off. The use of low temperature, dehumidi fied air which 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 by-pass 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 since the air delivered by each unit can be controlled individually. Selection 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. INDUCTION CONVECTORS--HIGH PRESSURE TYPE Another type of induction convector, Fig. 5, employs nozzles which produce a high velocity air jet without objectionable 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 con vector, is still less than the total resistance pressure of a conventional central system. The high velocity jet of primary air induces a flow of air from the room through coils located in the secondary air stream and supplied with chilled- water in summer and with hot water in winter. The chilled water removes 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 second ary air stream. Since the primary quantity is small, very high velocities can be maintained in the supply ducts without requiring fan power in excess of that for a conventional system. Therefore, the supply 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 man ner 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. The water piping for the coils can be so valved that hot water will be sup plied to one zone that may require heating, while cold water may be sup plied at the same time to a zone that requires cooling. This system usually is limited in application to hotels, apartments, office buildings and other multi-room installations having a large perime ter with relation to the floor area. The units usually are installed beneath the windows, replacing direct radiation or thermally-circulating enclosed convectors. Where the spaces to be conditioned extend a considerable distance from the outer wall into the interior of the building, a separate system or zone for the conditioning of the interior portions may be required. EVAPORATIVE COOLING . In climates where, on the hottest days, the outdoor wet-bulb depression 0 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 dryoulb temperature to within a degree or two of the entering wet-bulb condi- 662 CHAPTER 30 1954 Guide tion. 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, can be obtained. 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 cooling, it is still possible to use pre-cooling convectors with refrigeration, well water, or a cooling tower, as the basic source of sensible heat removal to reduce the wet-bulb tempera ture 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 evaporative cooling, and where the sensible heat load is not too great, intentional partial saturation may be employed. That is, 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 by-pass the humidifier. AH of these remarks with regard to evaporative cooling are based on the assumption that aU of the supply air will be taken from outside. Provision should be made in most cases for the return of some air from the condi tioned spaces for control purposes, as well as for economy of fuel in winter. PRECOOLING Where sufficiently cold water from weUs or streams is available, a saving in refrigeration may be obtained by the use, in location ahead of the de humidifier, of precooling coils through which the cold water is circulated. The resultant cooling of the air decreases the load to be carried by the dehumidifier and refrigeration plant. In normal practice the water, after passing through the precooling coils, may be further utilized in the refrig eration 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 depres sion 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 outdoor 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 saturation after the coil wiU reduce further the dry-bulb temperature and the air quantity required. This system has very definite application in hot dry climates. RUN-AROUND SYSTEM An interesting method of control is found in the use of combined re heating and precooling, usually termed the run-around system. Typically, three coils are placed in series in the air stream. The primary one receives liquid that has been cooled in the third coil. The center coil is main tained at a temperature colder than the dew-point of the air. The primary coil thus precools the air, and the third coil reheats the saturated air from the center coil. The third coil is heated by the relatively warm water coming to it from the primary coil. The run-around scheme has the advantage of permitting a higher supply air dew-point temperature than would be possible otherwise. This is due to the fact that continuous re-. Central Systems for Air Conditioning 663 heating is available, which is not a large penalty on the refrigeration plant since it provides precooling at the same time. This reheating at peak load creates an artificial sensible heat gain which increases the ratio of sensible heat to total heat and, for a given room temperature, results in a higher apparatus dew-point. Thus, while the volume of supply air is increased, the low-side temperature level of the refrigeration plant is raised and this may effect savings in initial and operating costs. The run-around system has the disadvantage of providing a decreasing amount of heat for reheat ing as the demand for reheating increases. SELECTION OF TYPE OF SYSTEM If the perimeter of the building is large with regard to the area, and if there are many rooms, induction convectors of either, the low or high pres sure type may be employed. Occasionally a dual system, one duct carrying air at a warmer temperature than the other, may be considered. 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 department stores it may be possible to pro vide a single conditioner, with a fan delivering the conditioned air to local mixing fans which supply the various departments or spaces. This appli cation 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 supplied by a separate fan delivering conditioned air to local mixing fans. In many cases the most economical and satisfactory scheme may be to employ a hot water or steam reheater 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 ade quately 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 sectionalizing 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 coUect in the lower story and the warm air is forced to the upper story. Balconies and large lobbies in theatres 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. - --uikiw at mu capacity continuously in many systems, and there fore should be selected for good efficiencies. In winter when higher temper ature differentials are used, it is sometimes practicable to deliver smaller air quantities than when cooling. In climates where winter temperatures fall below freezing, the tempering coils should be of the steam-distributing type; or if they are heated by a bquid, this liquid should contain some anti-freezing 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 by-pass dampers rather than by throttling the valves, to prevent damage due to freezing. If zone reheaters placed in supply duct branches are employed, 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-distriouting-tube coils or mechanicaUy circulated water coils are satisfactory in such cases, and throttling valves may be used. Refrigeration equipment must be carefully selected to satisfy the partic 664 CHAPTER 30 1954 Guide ular requirements of each installation. For some small plants the evapora tor 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 relative 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 possibili ties 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 refrig erant condensers that might permit the water to be used for drinking or lavatory purposes. Practically without exception, air cleaners should be provided for both outside and recirculated air. Control of temperature and of relative humidity by automatic means is vital, if comfort and economical operation of air conditioning equipment are to be attained. The insulation of ductwork is not merely a matter of economics, but sometimes is a necessity from the standpoint of limiting the temperature change of the air between the conditioning apparatus and the point of final delivery. Such temperature change of the air should be taken into account when apportioning the air and sizing the ducts. When computing heating or cooling loads, due allowance must be made for the effect of any hot or cold ducts or pipes contained in the space under consideration, and insulation must be incorporated where necessary or justified. Consider ation must also be given to the possibilities of condensation of moisture on either the inside or outside surfaces of pipes, ducts, housings, fan encase ments, etc., and insulation should be applied to prevent corrosion and water damage and to conserve refrigeration. The location of the apparatus room often is determined by building construction or available space. The closer the apparatus, room is to the conditioned space, the less expensive are the ducts. If the equipment is noisy, it should be located at some distance from the occupied spaces or be provided with adequate sound and vibration treatment. The scattering of wet apparatus throughout a building is to be avoided unless suitable precautions are taken. It must be remembered that encroachment on spaces that are otherwise usable should be charged against the system as an operating cost. 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 outside air intake, is: weather hood of louvers, outside air dampers, return air connection, filters, tempering coils, cooling coils or sprays, by-pass connection with or without reheaters, reheaters, fan and distributing ducts. Screens at the intake prevent the entry of large foreign matter, birds etc. A hood or louver at the outside air intake prevents the entry of rain and snow. Since in most climates there are many days during which use of 100 percent outside 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 by-pass connection normally connects the return air duct system with the apparatus casing between the conditioner and the supply fan- Central Systems for Air Conditioning 665 Usually the by-pass opening is sized to handle about 50 percent of the fan capacity where a variable by-pass is used though extreme load variations may require a larger size. It is at times good design to locate a reheating coil in the by-pass connection to permit using some by-pass air when heat ing is required. Since the relatively high resistance of the cooling coil or spray is to be balanced by the heating coil and by-pass connection, enough heating surface can be provided to raise the temperature of the by-pass air to the point where the mixture of by-passed air and conditioned air will have the required temperature. When a variable by-pass is used, a damper working in opposition to the by-pass damper should be placed across the face of the dehumidifier, for unless the resistances of the two are carefully balanced at all operating points, the proper mixtures of air will not be obtained. Outside air that has not been dehumidified should not be by-passed around a cooling coil or spray dehumidifier if accurate control of the delivered relative humidity is desired. Where the by-pass is made a part of the dehumidifier or conditioner and is located on the top or side of it, the return air connection should be arranged so that stratification of return air is insured, baffles being provided to accomplish this purpose if necessary. When return air and by-pass 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 by-pass connection. When the by-pass damper is at maximum opening it may be much easier for outside air to pass through the return damper, into the return duct connection and through the by-pass* than for return air to pass through the by-pass con nection into the fan. Air tends to take the path of least resistance and, if the dehumidifier resistance is high, and if the return duct resistances are low, this situation is apt to occur. A recirculating air fan, instead of a back-draft 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 outside air intake, preheaters, and return air connections precede the conditioner, while the by-pass, 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, including the dehumid ifier, will be dependent on the type of building, 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 dehumidifiers 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 tank, return water pumps will be required, and these pumps will have to be operated until the water supply hues are drained in order to prevent flooding 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 exceedlnSly important that water-tight (brained floors be provided under all 666 CHAPTER 30 1954 Guide overhead cooling systems, since water condensed put of the air generally will be present and may damage the interior finish of the rooms .below the 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 casing or connection 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 wherever 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 removing and repairing or replacing them should be provided. Adequate space should be provided for the servicing and replacement of eliminators. Whether these accom pany sprays or wetted coils, filters must be so located that the proper cleaning, replacement or routine servicing can be accomplished without difficulty. Free access to the bearings of all moving machinery is a neces sity. Provision should be made for the complete removal and replace ment of any parts of the apparatus that are subject to wear, deterioration or damage, whether they be filtered, fanwheel, motor, pump impeller, or heat transfer surface. DESIGN PROCEDURE The customary design procedure is outlined herewith. For simplifica tion the procedure is set up on the basis of a year-round system. For systems designed only for winter or for summer, the unrelated parts may be omitted. 1. Selection of design-conditions (inside and outside): (a) summer, (b) winter. 2. Determination of outside air requirements. . 3. Determination of cooling load: (a) room sensible heat gain, (b) room latent heat gain, (c) room total heat gain (d) grand total heat gain. 4. Determination of heating load: (a) room sensible heat loss, (b) room moisture loss, (c) humidification requirement, (d) total heating requirement. 5. Determination of apparatus dewpoint and dehumidified or humidified air quant ity: (a) summer (full load and part load), (b) winter. 6. Supply air temperature difference and quantity: (a) summer, (b) winter. 7. Equipment selection. 8. Equipment layout. The foregoing steps are merely typical. Many applications will require at least a preliminary investigation of some of the latter steps before pro ceeding with the earlier steps. A permanent record of all design assump tions and computations should be made and preserved for comparison with the performance of the installation. CHAPTER 31 AIR DISTRIBUTION Definitions, Standards for Satisfactory Conditions, Principles of Air Distribution, Ventilating Jets in Air Distribution, Outlet Performance, Outlet Types, Outlet Location and Selection, Direction and Volume Control, Return and Exhaust Intakes, Specific Applications. CORRECT air distribution is essential in warm air heating, ventilating, and air conditioning systems. Even though a system delivers the re quired quantity of conditioned air to a room, unsatisfactory conditions result if the air is poorly distributed. This chapter deals with room air distribution only; the transmission of air through ducts is treated in Chapter 32, Air Duct Design. The objectives of this chapter areto: 1. Describe the present state of air distribution problems by discussing ventilat ing jets in room air distribution. 2. Present general information on practical air distribution problems by discuss ing outlet performance, outlet types, and also location, selection, and control of outlets. 3. Illustrate the use of the basic concepts and of the practical experience gained in air distribution by discussing specific applications. Further pertinent information on air distribution will be found in Chapter 6, Physiological Principles; Chapter 12, Heating Load; Chapter 13, Cool ing Load; Chapter 19, Gravity Warm Air Systems; Chapter 20, Forced Warm Air Systems; Chapter 25, Unit Heaters and Unit Ventilators; Chapter 26, Unit Air Conditioners and Unit Air Coolers; Chapter 30, Cen tral Systems for Air Conditioning; Chapter 41, Sound Control; Chapter 48, Transportation Air Conditioning; Chapter 51, Instruments and Measure ments. DEFINITIONS The following definitions referring to air distribution equipment have gained general acceptance. 1. Supply Opening or Outlet: Any opening through which air is delivered into a space which is being heated, or cooled, or humidified, or dehumidified, or ventilated. 2. Exhaust Opening or Return: Any opening through which air is removed from a space which is being heated, or cooled, or humidified, or dehumidified, or ventilated. 3. Outside Air Opening: Any opening used as an entry for air from outdoors. 4. Damper: A device used to vary the volume of air passing through a confined cross-section by varying the cross-sectional area. 5. Grille: A covering for any opening and through which air passes. 6. Register: A grille equipped with a damper or control valve. , L free Area: The total minimum area of the openings in the air outlet or inlet through which air can pass. 8. Core Area: 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. Free Area Ratio: The ratio of the free area to the core area. 10. Coefficient of Discharge: Ratio of area at vena contracta to area of opening, U. Aspect Ratio: The ratio of length to width of an opening or core of a grille. 667 668 CHAPTER 31 1954 Guide 12. Vane Ratio: The ratio of depth of vane to minimum width between two adja cent vanes. , 13. Plaque: A ceiling outlet in which the supply air impinges against a plate or series of parallel plates, and is deflected horizontally in all directions. 14. Diffuser: An outlet discharging supply air in various directions and planes. 15. Primary Air: The air delivered to the outlet by the supply duct. 16. Induction: The induction of room air drawn into an outlet by the primary air stream (commonly called aspiration). 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 discharged 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 horizontally projected air stream drops between the outlet and the end of its throw. ; . .22. Rise: The converse of drop. ; . 23. Envelope: The outer boundary of an air stream moving at a perceptible ve locity. 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 outlet discharging supply air in various directions and planes. , 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. - 27. Outlet Velocity: The average velocity of air emerging from the outlet, measured in the plane of the opening. 28. Terminal Velocity: The average air Btream velocity at the end of the throw. 29. Temperature Differential: Temperature difference between primary and room air. 30. Temperature Variation: Temperature difference between points of the same space. STANDARDS FOR SATISFACTORY CONDITIONS . The object of air distribution in warm air heating, ventilating 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 motion. To obtain comfort conditions within this zone, standard limits have been established as acceptable effective temperatures. This term comprises air temperature, motion, humidity, and their phys iological' effect on the surface of the human body. Any variation from ac cepted standards of one of these elements may result in discomfort to the occupants. The same effect may be caused by lack of uniformity of condi tions within the space or by excessive fluctuation of conditions in the same part of the space. Such discomfort may arise due to excessive room air temperature variations (horizontally, 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 fluctuation of room temperature or air motion (gusts). . With reference to permissible room air motion it is not possible to es tablish a specific standard covering the entire complex problem of air dis tribution. Velocities less than 15 fpm generally cause a feeling of air stagna tion, 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 satis factory, but air motion of 20 to 50 fpm will usually be acceptable, with the lower values used in cooling applications, and the higher values on heating Air Distribution 669 jobs. The permissible air motion depends to some degree on the geographic location of the air conditioning installation. In addition 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 in formation on effective temperature and comfort lines, and to Chapter 41, Sound Control, for acceptable room noise levels and noise generated by air outlets. Material in Chapter 45, Industrial Air Conditioning, covers temperature and humidity requirements for products and manufacturing processes, and for health, safety and efficiency of workers. 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 outside of the zone of occupancy in order that air mo tion and temperature differences will be reduced to acceptable limits be fore the air enters the occupied zone, and (2) counteraction of the natural convection and radiation effects within the room. Practical room air distribution is predominantly an art depending upon clear recognition of physical principles, good judgment, and the cumula tive benefits of extensive experience. The characteristics and performances of air outlets are evaluated by experiment, and full-scale models are em ployed in order to develop satisfactory installation recommendations for specific applications. Frequently the performance of the air distribution system is checked in the field before the installation is turned over to the customer. Adjustments may be necessary before all requirements are met. Manufacturers' literature is available to provide data for the performance and application of various outlets which are usually based upon observa tions in full-scale test rooms. , The complexity of practical room air distribution is due to innumerable variations in building construction, system design, and operating require ments, and makes the exploration of the basic character of air distribution imperative. Research at the A.S.H.V.E. Research Laboratory1 and co operative programs at Case Institute of Technology2 since 1937 have ad vanced considerably the fundamental knowledge in air distribution. A comprehensive survey of the literature relevant to air distribution problems was made at the A.S.H.V.E. Research Laboratory in connec tion with the experimental investigation of ventilation jets.1(b) This survey deals with fundamentals of turbulence, jet behavior, and miscellaneous Problems, and is sufficiently complete to permit the study of these problems without requiring recourse to the original papers. Therefore, the survey is an indispensable and timesaving tool for every researcher in air distribution. VENTILATING JETS IN AIR DISTRIBUTION The theory concerning the distribution of conditioned air within an enclosure is still far from complete but a considerable fund of knowledge supported by experimental guidance is available for free jets, and par ticularly for axial-flow type free jets, both singly and in combination.2 for many conditions of jet discharge, therefore, it is possible to analyze let performance, and to determine (1). the angle of divergence of the jet Boundary, (2) the velocity patterns along the jet axis, (3) the velocity pro]e at any cross section in the zone of maximum engineering importance, nc* (4) the entrainment ratios in the same zone. In other words, it is possi- 670 CHAPTER 31 1954 Guide ble to answer the following questions about a jet discharged from any air supply outlet: 1. What is the shape of the jet (spread or coverage)? 2. How can the velocity at any selected point within the jet be determined? " 3. How far does the jet travel or what is its throw? A free jet is a straight-flow jet, free from pulsations or helical flow, which is discharged into a large open room in which no surfaces, objects, or con vection currents interfere with the formation of the natural flow pattern. Most of the available data refer to isothermal jets. Information given herein refers to this type unless otherwise noted. Types of Outlets Two general classes of outlets have been the subject of experimental study: Class !. Straight-flow devices, such as ducts, nozzles, orifices, slots, straight-flow grilles and multiple openings located close together, perforated panels being an extreme example. Class 2. Annular outlets including ceiling plaques, but not including diffusers. . Fig. 1. Cboss-Sections of Round Ducts with Three Basic Ttfes of Annular Outlets Fig. 1 shows three basic types of annular outlets. Outlet A is a circular slot in a wall or ceiling, and produces a jet similar to straight-flow jets. Outlet B discharges the jet radially from the axis of the approach duct, and also produces a jet quite similar to straight-flow jets. Outlet C, usually called a ceiling plaque, is a radial outlet with a plane boundary extending from one edge, but it cannot readily be correlated with outlet B. . Shape of Axial Jets A surprising similarity between the shape of the jets exists at a short distance from the outlet face, whether the outlet is round, rectangular, grille-like, or a perforated panel. Even in the case of wide-angle grilles or annular outlets, the similarities are such as to permit the same analysis of performance. The jet discharged from a round opening forms an expanding cone; whereas jets from rectangular outlets rapidly pass from rectangular to elliptical cross-sectional shape at a short distance from the outlet face, and then to a circular shape, at a rate depending primarily on the aspect ratio. ` The angle of divergence is very definite close to the outlet face, but the boundary contours are somewhat billowy and are easily affected by ex ternal influences. Here, as in air distribution generally, room air movement is replete with local eddies, vortices, and surges, which are manifestations Air Distribution 671' of unbalance in the forces acting within the air stream. These internal forces govern the air motion, yet they are extremely delicate. 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 multiple outlets expand at somewhat smaller angles, averaging 18 deg, and jets discharging into relatively small spaces show even smaller angles of expansion.3 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 where X < 1.5\/Ak X = distance from face of outlet, feet. Ar = cross-sectional area of the confined space, square feet. Four Zones in Jet Expansion In analyzing the performance of jets, four major zones can be distin guished. They may be roughly defined in terms of the maximum or center line velocity existing at the cross section being considered: Zone 1:'A short zone, extending about 4 diameters or widths from the outlet face (or vena contracts for orifice discharge), in which the maximum velocity of the air Btream remains practically unchanged. Zone 2: 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 rectangular outlets of large aspect ratio, this zone is elongated and extends from about 4 widths to a distance approximately equal to the width multiplied by four times the aspect ratio. Zone 3: A long zone, of major engineering importance, in which.the maximum velocity varies inversely as the distance from the outlet. This zone is often called the zone of fully established turbulent flaw 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 maximum velocity decreases rapidly in a few diameters to the velocity 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 ac curacy from Fi KD) K'y/Tt To X x- y _ K'VvVAt K'Q 1 x xVTo (1) (2) where _ K'Q xVac XCdX Rt. (2a) V* centerline velocity, feet per minute. V, V, .: . . .... bPi--j X- K(-a -- average initial velocity at discharge from open-end duct or across contracted stream at vena contracts of orifice or multiple opening outlet, feet per minute. 672 CHAPTER 31 1954 Guide To = nominal velocity of discharge based on the core area, feet per. minute. Cd = coefficient of discharge (usually between 0.65 and 0.90), t Jg.- = ratio of free area to gross (core) area. . X = distance from face of outlet, feet: ' K and Kf -- proportionality constants, with K' - 1.13 K Do .=. effective or equivalent diameter of stream at discharge from open-end ; duct or at a contracted section, feet. Ao = Ac X Cd X = effective area of stream at discharge from an open- end duct or at a contracted section, square feet. A,, = measured gross (core) area of outlet, square feet. Q = discharge from outlet, cubic feet per minute. Equation 1 is nondimensional and requires'only that consistent units be used, as in the above nomenclature. Values oi K and K' are listed in Table l.2- 4 K K'Table 1. Recommended Values of the Centebline Velocity Constant ob . . (See Equation 1) Ttpe of Outlet K. Vo - . 500 to 1000 , F.- 2000 to 10,000 K1 " 500^to 1000 Vo = 2000 to 10,000 Free Openings Round or Square Rectangular, large aspect ratio (<40) Annular slots' axial or radial* Grilles and Grids ' Free area 40% or more Perforated Panels . Free area 3 to 5% Free area 10 to 20% 5.0 4.3 _ .: 4.1 2.7 3.5. 6.2 5.3 __ 5.0 3.3 4.3 . 5.7 7.0 4.9 6.0 3.9 4.8 4.7 5.7 3.0 3.7 4.0 ' 4.9 : For radial slots use X/H instead of H is the height or width of the slot. Note: K and K* are indexes of loss in axial kinetic energy. Interpolate as required. Departures from maxi* mum value indicate losses in first and second zones when compared with tbe jet from a'rounded-entrance, circular nozzle. Low velocity test results, in the range Vx < 150 fpm, indicate that the normal values of K and K' should be reduced about 20 percent for Vx = 50 fpm, as used in later Equation 4b for throw. Fig. 2 gives the effective diameter Z)0 in inches for single openings and includes the coefficient of dis charge.5 Similar values for grilles are available in the literature or can be experimentally determined. Values of Cd and Ru are required for deter mining Vo, Do and Ao 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 (see diagram A of Fig. 1), the streams coalesce into a solid jet before actual jet expansion takes place. This coalescence affects the experimentally de termined proportionality constants K or K' and accounts for some of the divergence in reported values for similar outlets. Centerline Velocities in Zones 1 and 2 Experimental evidence indicates that in Zone 2 , Air Distribution where 673 1 Ho -- width of jet at outlet or at vena contracta. Approximately axial outlets. the same values of K' apply as for Zone 3 expansion from In Zone 1, the ratio Vx/Vo is constant and equal to the ratio of the een- SLOT WI0TM OR ORIFICE DIAMETER* INCHES . Fig, 2. Effective Diameters fob Round and Rectangular Openings ~ , (Plenum Approach) ter velocity of the jet at start of expansion to the average velocity, ranging from approximately 1.0 for rounded-entrance 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 ra tios are plotted against distance from outlet in Fig. 3 in accordance with 674 CHAPTER 31 1954 Guide the basic relation of Equation 2, and a nomogram for calculating the parameters V, X . Vx and Ao from VX and Vo through Rta and CA 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 Fig. 3 for Fig. 3. Chart for Determining Centerline Velocities of Axial and Radial Jets Zones 1 and 2. Fx/ Vo is plotted against X/H0 and, for a range of aspect ratios, against X/VA for the single value of K' = 7.0. Values of VjVo for_other values of K' may be obtained by direct proportioning of VK' to V7.0. The following Example 1 which is solved on Fig. 3 will illustrate the use of the chart,. , Example 1: A grille lias a core area 12 in. x 18.75 in., = 0.90, Ce = 0.80, and K' -- 5.0. Find V, (velocity through core area) when Vx is 50 fpm for throw of 50 feet (X = 50). . Solution: Air Distribution 675 For Vx = 50, x . 50 VAC 1.25 _ 40 Ac = 1.56 X 0.80 X 0.90 = 1.123 X 50 V ,, = 47.2 Ac 1.06 Vx K'.VXc 5-v/l.l23 = 0.106 Vc ' X 50 Vx Vx 0.106 V. = V,,(Cd AJ = 0.147 0.80 X 0.90 V = 0^7 = 340 fpm' The quantity of air discharged is then, Q = V0AC = 340 X 1.56 = 530 cfm. Throw ------ ----- Equation 2a can be used to determine the throw X of ah outlet, if the dis charge volume and the center velocity are known. ; or, if xX = IC_ _ Q Vx VAC Cd X Ru (4) Z -- V/Cd X Rla K' Q The maximum throw L is usually defined as the distance from the outlet face where the centerline velocity is 50 fpm. Therefore, for Fx = 50 fpm, l^x=e.q 50 Zy/T, (4b) Velocity Profiles of Jets . In Zone 3 of both axial and radial jets, the velocity distribution may be expressed by a single curve (Fig. 4) in terms of dimensionless coordinates, and this same curve can be used as a good approximation for adjacent por tions of Zones 2 and 4. Experiments have shown that temperature and density differences have but a small effect on cross-sectional velocity pro files. . Velocity distribution in Zone 3 can be expressed by the Gauss errorfunction or probability curve which is approximated by a simple equation using common logarithms where fc)5=3'3,0g Vx (5) r ~ the radial distance of the point under consideration from the centerline of the jet. 676 CHAPTER 31 1954 Guide % 3-- "V i V From Dcto oh Albertson (lowo) Forthmonn (Germany) * Ruden (Germany) - * Btthv IDeraftOtW) -- fe)'-33 ">() SJ at. IS `V * A 001--1--01.--2 1I 0.I* ' 0. 101.81I1I.0 I' I1.2 l--l.l I!I--1-.8-----*-I.---1--2-.10 Fig. 4. Cross-Sf.ctional Velocity Profiles fob Stbaightflow Turbulent Jets,?/*' Ts,.i = the radial distance in the same cross-sectional plane from the axis to the' point where the velocity is half the centerline velocity. (V = 0.5 V,). F, = the centerline velocity in the same cross-sectional plane, feet per minute.yw V = the actual velocity at the point being considered, feet per minute. y\ . Experiments show that the conical angle for 0-5 Vx and r0.6 is approxi-^N; m'ately one-half of the total angle of divergence of a jet. The velocity proig? file curve for one-half of a straight-flowturbulentjet (the otherhalf being's,i| symmetrical duplicate) is shown in Fig. 4. For multiple-opening outlets'll such as grilles, or perforated panels, the velocity profiles are similar, but^ the angles of divergence are smaller. . Radial Jets 'P J In t. he radial jet (di.agra.m B .in Fig. 1) the cross-sect.ional area at any di.s^-' tance from the outlet varies as the square of this distance, the same 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 ofjg) axial jets and that the angles of divergence are about the same. In using)*: Fig. 3, X/H should be used as abscissa instead of Xfy/A-' Jf!; Jets from ceiling plaques (diagram C in Fig. 1) have the same form as"! one-half of a free radial jet. The jet is wider and longer than a free jet, with; the maximum velocity close to the wall. This is demonstrated in Fig. which also indicates that under the conditions shown the width of the slot Nozzle . i ;<Kr* 14* ploque H2* 262 cfm 5-' Nozzle Sboded Areos Represent Measured Velocity Profiles ant; -risftv- Air Distribution 677 Fig. 6. Shape of Air-Stream Envelopes as Slot Area is Increased between ceiling and plaque has little effect on the jet pattern or velocities at some distance from the plaque.2 Discharge from a Long Slot When a long slot,receives its air supply from one end only, the important design 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 deT termined by this ratio4Figa6 shows the changing.profile as the slot areais increased for a rounded entrance slot (Ca = 0.93) with constant duct cross section. ... ....... ... . The air discharge from a slot in. a tapered duct will be uniform (Fig. 7) for a relationship between discharge angle and slot-duct dimensions7 where . cot 6 = A~ Ad (6) - 4 = discharge angle, degrees. .. A. = slot area, square feet. Ad = duct cross-sectional area'at upstream end, square feet. Ct * coefficient of discharge. : . Perforated Panels When air is discharged from perforated panels of relatively large sizes, the constant velocity core formed by the coalescence of the individual jets extends a considerable distance from the panel face. In this Zone 1 region the proportionality constants K and K' do not apply. Therefore, the pro portionality constants given in Table 1 should be used only when the ratio (Distance from panel/v/Panel area) is larger than 5. When the ratio is less than 5, the equation Vx = V0:1.2\/Cd X Rf. should be used for estimating centerline velocities.8 (7) gK^^X\\\\\\\\ Fig. 5. Air Jets from a 14-in. Ceiling Plaque for Two Slot Widths with Rate of Flow t lG- 7. Uniform Air Flow from a Slot Supplied bt a Tapered Duct 4's. 678 CHAPTER 31 1954 Guide. Fig. 8. Jet Velocity Patterns for a Square Outlet Discharging along Wall^ or Ceiling (Vo - 2260, A = 0.10, Ca = 0.78) ' Effect of Walls and Ceilings . Jets discharging parallel to a wall with one edge of the outlet coincidingjf, with the wall, take the form of one-half of an axial jet discharging from'ai|g outlet twice as large, similar to radial jets from ceiling plaques. Entrain?^ ment takes place practically only along the surface of a half cone and the-;,--; maximum velocity remains close to the wall.2 (Sefe Fig 8). Values of | and K' are approximately those for a free jet multiplied by y/2, that is tdfiC say, the normal maximum of 7.0 for K' for free jets becomes 9.9 for a sim-, ; . . - . . . X-'ix ilar jet adjacent to, and discharged parallel to, a wall, and in Fig. 3, ^y==p X should be used in place of --7= VTo ' _ .^ When a jet is discharged parallel to, but at some distance from a w%Ug?j its expansion in the direction of the wall is reduced and entrained air miist.jj be obtained by recirculation from the jet itself instead of from ambient^| air.3,9 The jet expands normally to within a short distance from the wwl;^ which nearer to the outlet only affects velocity distribution in the outeiv;,; shell of the jet, but further on also affects centerline velocities. This happens^ at some distance from a plane where the jet outline becomes parallel to tlSgfi wall, and where the jet enters its fourth or terminal zone. Few engineerujgi^, data are available on this important phase of jet expansion.3 `' / : life ^ -Wi." Fig 9. Entrainment Ratios for Straight-Flow Outlets Air Distribution 679 Effect of Resistance on Return Path of Jet Air Laboratory experiments on. jets usually involve recirculated air with negligible resistance to flow 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 flow of jet air to outlets, show that the expansion of the jet terminates abruptly at a distance that is in dependent of velocity of discharge and but slightly affected by size of out let. Such distances are determined primarily by size and length of return path. In a long 5 ft x 6 ft tunnel, a jet may not travel more than 25 ft z Peak Velocity . W 2o Source Velocity Vj -ID .1 : :* 3i \ -a --4 - -4 -JB .07 --46 -i-45 --SH -i-43 - -.02 - -JJ1 - 15 - -20 -30 -40 - -50 -l60 --70 -i hBO -90 -MOO - -150 -200 - -300 - -400 - -500 . BOO Fig. 10. Nomogram for Center, or Peak, Velocities for Rounded, . Rectangular Jet Sources 2-,,er(eas ln a relatively short opening, 25 by 60 ft, it may travel more than oO ft. Few engineering data are available on this phase of jet expansion ut it can be of great practical importance.3 Entrainment Ratios Equations for the entrainment of circular jets and of jets from long slots Ve been mathematically derived.10 They are: Eor third zone expansion of circular jets, Q* 2 X Qo \/Ao (8) 680 CHAPTER 31 : 1954 Guide For a long slot ; o. y k' y ih (8a) where , : Qx = total volume flow rate at distance X from face of outlet; cubic feet per ' ! minute. ' ' ! . Q0 = discharge, from outlet, cubic feet per minute. . V, . . X = distance from face of outlet, feet. 2b -> -ntooo -,:n --a -4 - -20 - - IS i -w --1 --5 4i -L) --0 Fig. 11. Nomogram tor Entrainment Ratios op Rounded, Rectangular Jet Sources K' = proportionality constant. . . do = effective area of stream at discharge from an open-end duct or at a con tracted section, square feet. Ho = width of slot, feet. ' Equations 8 and 8a have been used in plotting Fig. 9 for entrainment ratios. : The nomograms (Figs. 10 and 11) for center velocities and entrainment- ratios for jets emitted from circular sources, and from rectangular sources of all aspect ratios, are based upon recently developed theory.11 Air Distribution 681 OUTLET PERFORMANCE The results of the studies undertaken in room air distribution which have been presented in the foregoing section can be used as a basis for engineer ing design of supply outlets if the following is kept in mind: . 1. The method for finding jet velocities is based upon several approximations and the two recommended equations must be used with caution for extreme axial and radial distances. 2. The characteristics of the low-velocity regions.of ventilating jets are not yet well understood, and for both axial and radial jets the effect of the Reynolds number is not fully known. ., . 3. The quantitative treatment of the forces which govern room air distribution phenomena has been limited, and non-isothermal conditions involving buoyant forces have not yet been fully explored. . 4. All investigations have been concerned with free jets, whereas air streams in practical room air distribution are not free streams but are influenced by walls, ceilings, floors and obstructions. 5. The science of air distribution has not yet reached its final stage where a basic theorem permits the exact mathematical solution of all problems, and velocity pat terns in closed rooms, and of a great variety of outlets, such as radial and slotted outlets, diffusers and perforated panels, must be further studied before their per formance can be predicted with confidence. However, the air distribution research sponsored by The American Society of Heating and Ventilating Engineers has proved that the phenomena of room air distribution are amenable to scientific research and rational interpretation, and the ventilation jet problem has reached a stage where a definite technique of experi mentation in combination with semi-empirical theories can be of great help in the design of air outlets. 6. In the design of air outlets, the days of unguided and unrelated experimentation should be over. Practical room air distribution, however, is still predominantly 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. In designing a satisfactory air distribution system, the engineer must make use of such tests and draw on this experience; and weigh the different factors of the outlet performance which place considerable limitations on his proceedings. A short dis cussion follows regarding some of these factors which are: (1) jet pattern, (2) capac'ty, (3) temperature differential, (4) permissible room air motion, (5) permissible noise level, and (6) smudging. Jet Pattern Refer to section Ventilating Jets in Air Distribution for a general discus sion of the jet pattern. In selecting the throw and drop of outlets the follow ing considerations are important: (1) throw, (2) effect of vanes, (3) effect f type of outlet, and (4) drop. Throw. The throw of a wall outlet must be sufficient to produce satisfactory conditions over the area to be conditioned. Underblowing may cause heated air to rise too rapidly above the occupied zone and thus create excessive vertical tem perature variation (stratification); in cooling operation it may cause cold air to drop th k18 occuP'B<i zone before supply and room air are mixed sufficiently, and thereby create a condition of acute discomfort (draft). On the other hand, over flowing will result in objectionable downdrafts from any surface the primary air stream may strike. f *'*le average, it is considered most practicable to select a throw which is three- on?' 8 d'sfance toward an exposed wall or window, as shown in diagram A ti ^owever> structural characteristics, mounting height of outlet, temperalo*j differential, and resultant drop or rise, or location of greatest heating or cooling i a"s strongly affect the selection of the optimum throw. In spaces with beamed ceiithe outlets should be located below the bottom of the lowest beam level, and ah In k y 'ow enough so that an upward or arched blow may be employed. The blow ould be arched sufficiently to miss the beams and, at the same time, in such a man- stn f55 to Prevent the primary or induced air stream from striking furniture and ob- acles, and producing objectionable drafts. ' 2. Effect of Vanes. Vanes affect grille performance if their depth corresponds at 682 CHAPTER 31 1954 Guide 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 impos sible. 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 throw of the discharged air stream. . A grille with diverging vanes (vertical vanes with uniformly increasing angular de flection 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 divergence the quantity of air handled by the grille for a given duct static pressure will decrease. A grille with converging vanes (vertical vanes with uniformly 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 converge 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, horizon tal vanes may be used to spread the air vertically. However, spreading the air verti cally 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 downward air motion. Therefore, both throw Fig. 12. Throw of Wall Outlets (radius of diffusion) and mounting height are important and interdependent factors. Due to the 360 deg spread, the rate of induction is higher and the throw shorter than that for a wall grille handling the same air quantity at the same outlet velocity. Therefore, ceiling diffusers willfrequently 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 amstream along the ceiling surface restricts induction of secondary air, and the throw is in creased 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 compa rable round or square vaned outlets of equal area handling the same air quantity, and their throw is shorter. (Refer to Discharge From a Long Slot in section Ventilat ing 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 greatest 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 ceiling outlets the following considerations should be noted' (1) if the temperature of the supply air is below that of the room, it should be thor oughly mixed with the room air before it enters the occupied zone; (2) air slightly above room temperature will usually be properly distributed by outlets selected for cooling; and (3) if the temperature of the supply air is substantially higher than that of the room, it should be projected downward in a broad diverging pattern to avoid stratification and to obtain proper mixing and controlled air flow. i 4. Drop. The 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 he located high enough for the air stream at the termination of the throw to be not less than. or 6 ft above the floor level, or in other words, the drop should not be more than the difference between mounting height and zone of occupancy (Diagram A of Fig- lTM. Air Distribution 683 As illustrated in diagram B of Fig. 12 the maximum permissible throw for a given ceiling height may be obtained by locating 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. (Refer to Chapters 11, Infiltration and Venti lation, 12 Heating Load, and 13 Cooling Load). Manufacturers' rating sheets are usually consulted for selection of the proper number, size, and type of outlets for a given air quantity. The basis of rating should be care fully noted to make certain that resulting velocities are suitable for the application. Temperature Differential The temperature difference between supply and room air is highly im portant, because temperature control in the conditioned 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 Effectual Temperature Difference in Chapter 30, Central Systems for Air Conditioning. Room Air Motion To achieve a constant air motion in the occupied zone without 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: excessive air discharge velocities; high air volume per cubic foot of space (often referred to as number of air changes per hour); pre mature drop of cold air into the occupied zone; overblow causing spilling of high velocity air into the occupied 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 downward projection of air may sometimes even be necessary if the supply air temperature is substantially higher than the room tempera ture. (Refer to section on Throw): Sometimes excessive air motion may be encountered in correctly de signed air distribution systems due to drafts occurring, 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 designed for heating and ventilation only may easily cause complaints of drafts when cooling is added. Permissible Noise Level The increase of the noise level caused by an outlet is primarily a funcI on of its discharge velocity and its size. The maximum acceptable noise level in a space may dictate completely the selection of the permissible out :684 CHAPTER 31 1954 Guide let velocity. In addition, however, noise may be caused by excessive re striction of the free outlet area due to outlet design, by unnecessary turbu lence due to one-sided air flow through the outlet, or by the impingement of high velocity air on sharp edges. The origin of excessive noise may be spotted by removing the outlet with out stopping the air supply. If noise is still evident, other elements of the air conditioning system or entirely different sources are at fault. Highpitched, rushing noise indicates that the duct system or excessive velocities in the duct are the cause, low-pitched rumbling noise points to the mechan ical equipment of the air conditioning plant. When very high duct velocities are used, sound absorbing lining or special acoustical filters (sound traps) must be provided. High pressure or high velocity outlets for multi-room and other buildings are equipped with a. special pressure 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 41, 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, small 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 ofthe air on any ceiling or room surface. Floor outlets may offer objection as dirt collectors. . TYPES OF AIR OUTLETS Air supply outlets for commercial, industrial and residential applications are either side wall or ceiling type outlets. In homes, baseboard and-floor type outlets are also used. (Refer to Chapter 19, Gravity Warm Air Systems, and Chapter 20, Forced Warm Air 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 application of out lets, reference should also be made to sections Outlet Location and Selec tion and Specific Applications of this chapter. 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 directional air flow is unnecessary, and for apphcations where the grille size can be increased in order to provide the required 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 controloi air motion is essential. Vanes should be designed for quiet operation. .1 Air Distribution 685 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 features 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 airperimeter 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, con.. Bisting either of elongated outlets with perforations, 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 entrain ment than comparable round or square vaned outlets of equal area and consequently, 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 unobtnisively with the room decoration. They may be used for either ceiling or wall air distribution, including the so-called under-the-window application. 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-Velocity Outlets. Ejector nozzles operate at high static pressure and convert this pressure into velocity pressure with resulting high induc tion of room air. They are mainly used for industrial process installations, particu larly drying. Another type of ejector nozzle is sometimes referred to as a louver ru>zzle 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 adjustability and are, therefore, useful for spotcooling in confined 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 iq. turn requires the use of high-pressure or high-velocity air outlets which reduce the velocity and pressure and attenuate the sound to predeter mined 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 con ventional 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 Induction Convectors for multi-room buildings in Chapter 30, Central Systems for Air Conditioning. - Ceiling Outlets Ceiling outlets in general use are (1) ceiling plaques, (2) ceiling diffusers, (3) high pressure or high velocity ceiling outlets, and (4) perforated ceilings and panels. b Ceiling Plagues. (Diagram C of Fig. 1). Plaques are of simple design. The air irom the supply opening impinges on a plate and is discharged horizontally. Plaques are inexpensive, but as the air is not always uniformly discharged in all directions, Proper control is difficult. oi U Diffusers. Ceiling diffusers are round, square, rectangular or slotted diff tS vaPous designs installed on, or parallel to, the ceiling. Performance of the -7TM* designs varies according to the principle employed. Some have no internal auction, but hasten external induction by supplying air in multiple layers. Others eftVe 'Plernal induction and distribute air over an entire hemisphere. The induction B >s greatest in the direction of the axis of the outlet, and least in the plane perintV|1CUar to ^e ax'6 and located at the ceiling level. Thus the induction is greatest l,overtical direction where the least throw can be tolerated, and least in the izontal plane at the ceiling where the greatest throw is desired. Refer to section Slotted Outlets under Wall Outlets. 686 CHAPTER 31 1954 Guide 3. High-Pressure or High-Velocity Outlets. Refer to text in section Wall Outlets. 4. Perforated Ceilings and Perforated Panels. These devices discharge air through perforations in the ceiling or part of the ceiling, and share with slotted outlets the Advantage 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 outlet 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 velocities. 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 location 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 distribu tion 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 construction of the individual rooms of a building, such as height and shape and the location of beams and other obstructions, influences 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 distri bution may be highly desirable but it may be impossible to use it, due to the location of beams and masonry walls. Refer to section Specific Applications for a discussion 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, determine 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 dissipated 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 outside temperature, a return fan, if it is below this temperature. Either method reduces the requirements for supply air. If the fights are exposed, Air Distribution 687 less saving can be realized than if they are enclosed, as a considerable por tion 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 possible 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 radiation under the windows, in addition to the wall or ceiling air distribution outlets. This solution must be used for com fort installations in northern latitudes (outside 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 neutralization of the downdrafts is so great that the air motion in the room exceeds comfort limits. Where com fort conditions are not critical as in factories for heavy manufacturing, ware houses, etc., satisfactory results with high induction outlets can be obtained even in cold climates. For uninsulated walls and glass areas in these build ings some supplementary heating is often valuable. Wall diffusers, direct radiation.or warm panels will satisfy these requirements for supplementary 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 oc cupied space. Great care should be exercised in the use of supply-exhaust 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 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 ph>'sical 'aws a'r distribution have, of course, a highly important influence upon the design of an acceptable distribution system. Refer to section Ventilating Jets in Air Distribution for a discussion of the theory, and to section Outlet Performance for some specific advice with regard to such features as throw, drop, capacity, temperature differential, room air motion, permissible noise level, smudging and their influence upon practical air distribution. Outlets should perform efficiently and conform to the esthetic appearance 688 CHAPTER 31 1954 Guide of the room. The physical appearance of air outlets has been highly in fluenced 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 de veloped in the past years. Linear-type outlets and perforated ceilings or panels have the advantage of unobtrusive 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. Tl)e amount of outside air introduced into the room must be checked against the ventila tion 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 impor tant point to consider is the combination of proper outlet location and efficient duct design (see Chapter 32). Consult manufacturers' tables for recommended location and spacing of outlets. - Refer to Chapter 30 for a discussion of zoning and zone control. 4. Select size of outlets according to air quantities handled, permissible throat or discharge velocities, of 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, type, size and location of the outlet must be checked against manufacturers' ratings. The most important questions to be con sidear.eWd aillred:rafts be created because of divergence between rated throw (radius of diffusion) and distance between outlet and nearest obstacle of air stream (wall, beam, column, etc.)? b. Will drafts be created because of excessive cooling temperature differential or . too low mounting height of the outlet? . c. Will drafts be created because of too low velocity energy of the air stream, causing excessive downward air flow in cooling installations? d. Will the air pass through the outlet at too high a velocity and thereby cause an excessive increase in noise level? Balancing the System In designing a system, the engineer aims to size duets 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 systems must be balanced, that is, the amount of air through supply ducts, supply outlets, outside air intakes, exhausts, return outlets and ducts must be properly adjusted so that the air quantities correspond closely with the design quantities. 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 outside air ducts, splitter dampers, or dampers in outlets.. In selecting the desired type of damper or balancing method, the follow ing points should be kept in mind: v Air Distribution 689 1. Unfavorable effect on air stream and noise level.should be avoided. This will often rule out blank-offs or dampers in outlets, unless such dampers are of special design. , ; ..... 2. It should be possible to alter outlet volume without altering the direction of discharged air, and to measure the amount of air handled without difficulty. Blank! ing 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 iri 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 section Directional and Volume Control for discussion of various air distrb bution control devices.) ; - . ; .. ' / Instruments for 'balancing include instruments' for' measuring air quan tities, static pressure, temperature and humidity. Commonly used instriri meats are the rotating vahe'anemometer," deflecting vane anemometer) thermal anemometer, smoke gun, clamp type ammeter-voltmeter, sling 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 manufacturer for the tube used. (See Air Flow Measurement in Chapter 51.)/ - .... . ". .- ' : 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 ane mometer inside the fan inlet plenum. For exhaust 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 capacity 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 possibility of overloading the motor, : . The procedure outlined may be shortened depending on the type of in stallation. 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 valuble in determin ing 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 obtain correct air distribution, the velocity of the air stream must be as uniform as possible over the entire connection to 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 cross-section, Provided the system is carefully designed. However, very few outlets are msjal!ed ru this manner. Most side wall outlets are installed either at the ePd of vertical ducts or in the side of horizontal ducts, and most ceiling 690 CHAPTER 31 1954 Guide 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 in vestigated for vertical stack heads with plain openings12 or equipped with grilles12 and for side outlets on horizontal ducts.14 In the tests conducted with the stack 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. 13 shows the direction of flow, distribution and velocity (measured 12 in. from opening) of the air for various types of stack heads tested, expand ing 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 direc tion of flow and. the distribution pattern are generally indicative of per- Air Distribution 691 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, installed 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 (ex haust) 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; Hinges 'a A Either two ,, ,, high velocity AB Fig. 13. Outlet Velocity and Aib Direction Diagrams for Stack Heads with Expanding Outlets . . Stack 14 in. x 6 in. Outlets 14 in. x 0 in. Stack Velocity 500 fpm A. Rounded Throat and Rounded Back. ' C. Square Throat and Back and 6 Guide Vanes. B. Rounded Throat and Back and 2 Splitters. 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 6 x 6 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 deflectors. A single scoop type deflector at the outlet did not improve the flow pattern obtained from a plain outlet, and was there fore not found to be desirable. Directional Control Many devices for directing and equalizing air flow in side wall and ceil ing 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 supply 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 resemble those for side outlets in horizontal air ducts. Ceiling ducts often have a rectangular cross-section, while the connections to the ceiling outlets are circular. It will then be quite difficult to install turning vanes successfully, particularly Fig. 14. Effect of Various Damper Arrangements Designed for Straight Blow (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 intermedi ate 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 respective 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 out let, 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. It is easier to handle than a splitter damper, since nly 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 (see C Fig. 14). 5. Louver Dampers. Numerous designs have been developed incorporating a series f 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 Uut&Uation. Some designs provide for louver blades moving in opposite directions, Jd while decreasing free air passage area, retain a constant air flow direction along axis of the duct air outlet connection (see A and B in Fig: 14). 692 CHAPTER 31 1954 Guide Table 2. Recommended Return Intake Pace Velocities Intake Location .. . , __ Undercutting of doors (through undercut area)........ VELOC1TX Over Gross Area Fpm 800 up 600-800 400-600 200-300 200-300 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 directions 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 veloci ties 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 control or directive devices. 3. Noise. The problem of noise generated by return intakes is the same as that for . supply outlets. In computing resultant room noise levels from the operation of an air conditioning 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 installation of the latter at ear level. When so located, it is recommended that the return intake velocity be not in excess of 75 percent of the maximum per missible outlet velocity. ., : The location of return and exhaust intakes does not critically affect air motion, unless room air velocities in the occupied zone near the intake exceed comfort limits. The locations of return or exhaust intakes are, how ever, important for obtaining the desired room temperature equalization. Ceiling locations for exhaust outlets are recommended for bars, kitchens, lavatories, dining rooms, club rooms, etc. where warm air will rise to the ceiling level. In heating installations, location of the return grilles in the ceiling or high on the wall is not recommended, as it may result in stratifica tion of the conditioned air, and--depending on the relative location of supply and return outlets--in short-circuiting. (Refer to section Outlet Location and Selection). , Some ceiling outlets combine the supply and return openings in a single Table 3. Approximate Pressure Drops fob Lattice Return Intakes - - t,, y-T---- a , Per Cent Free Area 50 60 70 80 400 0.06 0.04 0.03 0.02 500 0.09 0.06 0.05 0.03 Face Velocity, Fpm 600 0.13 0.09 0.07 0.05 700 0.17 0.12 0.09 0.07 800 0.22 0.16 0.12 0.09 900 0.28 0.20 0.15 o.n 1000 0.35 0.24; 0.18' 0.14, Air Distribution 693 Fig. 15. Air Distribution Methods for Theaters, Churches, and Auditoriums unit. This method is used for heating as well as for cooling applications. However, the application for heating is more critical and requires considera tion of ceiling height,, amount of outside wall area, and number of air changes required. In some cases, stratification of warm air may cause shortcircuiting. (Refer to section Outlet 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 ex haust. The pressure drop through door returns should not be excessive; otherwise the air distribution to the room may be seriously unbalanced with the opening or closing 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 diffusers, and the horizontal distribution system with ejector nozzles or wall diffusers. Fig. 15 shows both methods. Ceiling distribution is accomplished by ceiling outlets under main ceiling and balcony. It is indicated when main ceiling or 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 some times 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 -o*- Winter convection current Fig. 16. Distribution ..Methods for Small Rooms ____________ _,__ uiuauu ituums A. Satisfactory for cooling. Unsatisfactory for beating in severe climates where the outside temperature insistently below 40 Ff and single glass and uninsulated walls are prevalent. Performance approximately that of A when small diffusers are used in bottom of the duct. C. Satisfactory for cooling. Satisfactory for heating if direct radiation is properly controlled. Satisfactory for both cooling and heating. The air should be discharged slightly away from the wall for low velocities, should be fanned out parallel to the wall. ' ' 694 CHAPTER 31 1954 Guide 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 ornamentation. For large theaters, relatively high velocities can be used. These will work satisfac torily if adjustable outlets are used to avoid areas of local turbulence. In small or medium size theaters, it is sometimes practicable to use side wall or front wall distribution. For the satisfactory operation of such a Fig. 17. Small Store Cooling Distribution A. Rear Wall. High outlet velocity, satisfactory if properly designed; possibility of excessive air motion and drafts if used for wrong application. B. Front Wall. High outlet velocity, results same as A. C. Front and Rear Walla. Moderate room air motion, outlet blowsshould not impinge givingrise to down drafts in center. . D..Center. Moderate air motion, no impingement of air streams. Good results. E. One Side. Moderate room air motion; should blow toward exposed wall. Good results. F. Ceiling. Low room air motion. Good results. Outlets should be selected of sufficient sire to allow for blocking when not located in perfect squares. 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 infiltration from exits. For multi-room buildings diagrams shown in Fig 16 illustrate distribution methods for small rooms with exposed wall, such as offices, hotel (guest) rooms, hospital (patients) rooms, apartments, etc. For a small store the cooling performance of various distribution methods is illustrated in Fig. 17. REFERENCES 1 Ventilation Jets in Room Air Distribution, by H. B. Nottage. Originally sub mitted as a Ph.D. thesis to Case Institute of Technology. (3 volumes) Loan copies available from A.S.H.V.E. Research Laboratory. (a) Volume I: Data and interpretations of tests for ventilation jets discharging horizontally into a large confining space. 131 pages + 67 fig. + 9 tables. (b) Volume II: Appendix A. Survey of the literature on the problems of ventila tion jets and the related fundamentals of turbulent flow. 499 pages incl. figs- (c) aVnodlutmabeleIsI.I: Appendixes B to H. General features of the experimental installa tions, instrumentation, and operations, boundary-layer theory and work- energy treatment. (142 pages incl. figures). 'Air Velocities in Ventilating Jets, by G. L. Tuve (A.S.H.V.E. Journal Sec tion, Healing, Pi-ping & Air Conditioning, January 1953, p. 181). . * Air Flow at Discharge of Fan-Pipe Lines in Mines, by G. E. McElroy ((/ SBureau of Mines Report of Investigations R. I. 3730. November 1943, p. 19.) Air Distribution 695 ` A.S.H.V.E. Research Report No. 1404--Comparative Study of Ventilating Jets from Various Types of Outlets, by Alfred Koestel, Philip Hermann, and G. L. Tuve (A.S.H.V.E. Transactions, Vol. 56, 1950, p. 459). 5 Throw of Air from Slots and Jets, by R. D. Madison and W. R. Elliot (A.S.H.V.E. Journal Section, Healing, Piping & Air Conditioning, November 1946, p. 108). 6 A.S.H.V.E. Research Report No. 1328--The Discharge of Air from a Long Slot, by Alfred Koestel and G. L. Tuve (A.S.H.V.E. Transactions, Vol. 54, 1948, p. 87). 7 The Control of Air Streams from a Long Slot, by Alfred Koestel and C. Y. Young (A.S.H.V.E. Transactions, Vol. 57, 1951, p. 407). 8 A.S.H.V.E. Research Report No. 1366--Air Streams from Perforated Panels, bv Alfred Koestel, Philip Hermann, and G. L. Tuve (A.S.H.V.E. Transactions, Vol. 55, 1949, p. 283). 8 Isothermal Ventilation--Jet Fundamentals, by H. B. Nottage, J. G. Slaby and W. P. Gojsza (A.S.H.V.E. Journal Section, Heating, Piping & Air Conditioning, January 1952, p. 165). * 10 Entrainment in Ventilating Jets, unpublished paper (Case Institute of Tech nology). u Computation Charts and Theory for Rectangular and Circular Jets, by Harold G. Elrod, Jr. (A.S.H.V.E. Journal Section, Heating, Piping & Air Conditioning, March 1954). ,1! A.S.H.V.E. Research Report No. 1155--The Performance of Stack Heads, by D. W. Nelson, D. H. Krans and A. F. Tuthill (A.S.H.V.E. Transactions, Vol. 46, 1940, p. 205). 13 A.S.H.V.E. Research Report No. 1206--Performance of Stack Heads Equipped with Grilles, by D. W. Nelson, D. H. Lamb and G. E. Smedberg (A.S.H.V.E. Trans actions, Vol. 48, 1942, p. 279). 13 A.S.H.V.E. Research Report No. 1226--Performance of Side Outlets on Hori zontal Ducts, by D. W. Nelson and G. E. Smedberg (A.S.H.V.E. Transactions, Vol. 49: 1943, p. 58). BIBLIOGRAPHY Note: Many theoretical papers on air jets have been published which--though highly interesting and even fascinating to the specialist--are of little value to the practicing engineer. This guide to the literature on air distribution is, therefore, purposely restricted to papers resulting from research sponsored by The American Society op Heating and Ventilating Engineers and other papers of interest to engineers which are easily accessible to them. For an excellent survey of the entire literature the reader is referred to Reference 1. A.S.H.V.E. Research Laboratory A.S.H.V.E. Research in AiT Distribution and Ait Duct Friction, by Cyril Tasker. (A.S.H.V.E. Journal Section, Heating, Piping <fc Air Conditioning, April 1948, p. 125). . A.S.H.V.E. Research Report--Ventilation Jets in Air Distribution, by H. B. Nottage (See Reference !) The following papers based on this report have been published: A.S.H.V.E. Research Report No. 1360--Turbulence--A Fundamental Frontier in Air Distribution, by H. B. Nottage (A.S.H.V.E. Transactions, Vol. 55,1949, p. 193). A.S.H.V.E. Research Report No. 1402--A Simple Heated-Thermocouple Anemometer, by H. B. Not tage (A.S.H.V.E. Transactions ---------------------- Vol. . 56, vu, 1950, p. p. %4301l)).. q, A.S.H.V.E. Research Report--Isothermal Ventilation-Jet Fundamentals, by H. B. Nottage, J. G- 1952 ^^ ^ Gojsza (A S-H.V.E. Journal Section, Heating, Piping & Air Conditioning, January A.S.H.V.E. Research Report--A Wire Direction Probe, by H. B. Nottage, J. G. Slaby, and W. PGojsza (A.S.H.V.E. Journal Section, Heating, Piping <fe Air Conditioning, April 1952, p. 123). u A.S.H.V.E. Research Report--Outlet Turbulence Intensity as a Factor in Isothermal-Jet Flow, by *?-B. Nottage, J. G. Slaby, and W. P. Gojsza (A.S.H.V.E. Journal Section, Heating. Piping tfc Air Condi(lontng. May 1952, p. 117). .. A.S.H.V.E. Research Report--A Smoke-Filament Technique for Experimental Research in Room pl.r Pistribution, by H. B. Nottage, J. G. Slaby, and W. P. Gojsza (A.S.H.V.E. Journal Sectionf Heating, <1: Air Conditioning, July 1952, p. 123). . 0 A.S.H.V.E. Research Report--Exploration of a Chilled Jet, by H. B. Nottage, J. G. Slaby, and W. P. Lojsza (A.S.H.V.E. Journal Section, Healing, Piping <fe Air Conditioning, August 1952, p. 122). AA-.SS.UH-WV.TE>. Cnooperative --Research at Case Institute of Technology . A.S.H.V.E. Research Report No. 1140--The Use of Air Velocity Meters, by G. L. Tuve, D. K: Wright, Jr- and L. J. Seige] (A.S.H.V.E. Transactions, Vol. 45, 1939, p. 645). A.S.H.V.E. Research Report No. 1162--Air Flow Measurements at Intake and Discharge Openings &nd Grilles, by G. L. Tuve and D. K. Wright, Jr. (A.S.H.V.E. Transactions, Vol. 46, 1940, p. 313). \ 696 CHAPTER 31 1954 Guide A.8.H.V.E. Research Report No. 1204--Entrainment and Jet-Pump Action of Air Streams, by G. L. Tuve, G. B. Priester, and D. K. Wright, Jr. (A.S.H.V.E. Transactions, Vol. 48, 1942, p. 241). - A.S.H.V.E. Research Report No. 1248--Control of Air Streams in Large Spaces, by G. L. Tuve and G. B. Priester (A.S.H.V.E. Transactions, Voi. 50,1944, p. 153). A.S.H.V.E. Research Report No. 1328--The Discharge of Air from a Long Slot, by Alfred Koestel and G. L. Tuve (A.S.H.V.E. Transactions, Vol. 54, 1948, p. 87). . ,.. A.S.H.V.E. Research Report No. 1366--Air Streams from Perforated Panels, by Alfred Koestel, Philip Hermann and G. L. Tuve (A.S.H.V.E. Transactions, Vol. 55, 1949, p. 283). ' A.S.H.V.E. Research Report No.T404--Comparative Study of Ventilating Jets from Various Types of Outlets, by Alfred Koestel, Philip Hermann, and G. L. Tuve (A.S.H.V.E. Transactions, Vol. 56, 1950, p. 459). ... ;. A.S.H.V.E. Research Report--The Control of Air Streams from a Long Slot: by Alfred Koestel and C. V. Young (A.S.H.V.E. Transactions; Vol. 57, 1951, p; 407). . ' A.S.H.V.E. Research Report--Air Velocities in Ventilating Jets, by G. L. Tuve (A.S.H.V.E. Journal Section, Heating, Piping & Air Conditioning, January 1953, p. 181). : . . ` - . A.S.H.V.E. Cooperative Research at Kansas State College . A.S.H.V.E. Research Report No. 1327--Downward Projection of Heated Air, by Linn Helander and C. V. Jakowata (A.S.H.V.E. Transactions, Vol. 54,1948, p. 71). A.S.H.V.E. Research Report (In Cooperation with the Industrial Unit Htaler Association)--Maximum Downward Travel of Heated Jets from Standard Long Radius ASMS Nozzles; by Linn Helander, S. M. Yen, and R. E. Crank (A.S.H.V.E. Journal Section, Heating, Piping and Air Conditioning, March 1953, p. IS). A.S.H.V.E. Cooperative Research--General ` A.S.H.V.E. Research Reports No. 857, 911 and 968--Measurement of the Plowof Air Through Registers and Grilles, by E. L. Davies (A.S.H.V.E. Transactions, Vol. 36, 1930, p. 201; Vol. 37, 1931, p. 619 and Vol. 39; 1933, p.t'373). -. " . .. : , A.S.H.V.E. Research Report No. 1076--Air Distribution from Side Wall Outlets, by D. W. Nelson and D. J. Stewart (A.S.H.V.E. Transactions, Vol. 44,1938, p. 77). .- A.S.H.V.E. Research Report No. 1092--The Flow of Air Through Exhaust Grilles, by A. M. Greene, Jr. andM. H. Dean (A.S.H.V.E. Transactions, Vol.`44, 1938, p. 387). ' A.S.H.V.E. Research Report No. 1155--The Performance of Stack Heads, by D. W. Nelson, D. H. Krans, and A. F. Tuthill (A.S.H.V.E. Transactions, Vol. 46, 1940, p. 205). . ' A.S.H.V.E. Research Report No. 1165--Development of Instruments for the Study of Air Distribution in Rooms, by A. P. Kratz, A. E. Hershey, and R. B. Engdahl (A.S.H.V.E. Transactions, Vol. 46, 1940, p. 351). ' A.S.H.V.E. Research Report No. 1206--Performance of Stack Heads Equipped with Grilles, by D. W. Nelson, D. H. Lamb and G. E. Smedberg (A.S.H.V.E. Transactions, Vol. 48, 1942, p. 279). A.S.H.V.E. Research Report No. 1226--Performance of Side Outlets on Horizontal Ducts, by D. W. Nelson.and G. E. Smedberg (A.S.H.V.E. Transactions, Vol. 49, 1943, p. 58). Other Papers Presented at A.S:H.V.E. Meetings A.S.H.V.E. Research Report No'. 1051--The Noise Characteristics of Air Supply Outlets, by D. J- Stewart and G. F. Drake (A^S.H.V.E. Transactions, Vol. 43,1937, p. 81). . A.S.H.V.E. Research Report No. 1158--Dirt Patterns on Walls, by R.A. Nielses (A.S.H.V.E. Trans actAio.nSs.H, V.Vo.lE. .46R, e1s9e4a0,rcph. 2R47e)p. ort No. 1361--Balancing Air Delivery of a Sy, stem of Manifold Air Diffusers, by G. S. Dauphinee and Peter Argentieri (A.S.H.V.E. Transactions, Vol. 55, 1949, p. 213). A.S.H.V.E. Research Report No. 1362--Air Distribution and Draft, by John Rydberg and Per Norback (AAS..SH..HV..EV..ET.rRanessaecatricohnsR, Vepool.r5t5--, R19o4o9,mp.A2i2r5D). istributio n 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 (A.S.H.V.E. Journal Section, Heating, Piping & Air Conditioning, April 1953, p. 121). A.S.H.V.E. Research Report--Room Air Distribution Research for Year 'Round Air Conditioning, Part II--Supply Outlets at .Three Floor Locations, by H. E. Straub and S. F. Gilman (A.S.H.V.E. Journal Section, Heating, Piping <& Air Conditioning, November 1953, p. 145). , Miscellaneous Articles Measuring Air Distribution and Grille Performance in Air Conditioning, by G. L. Tuve (A.S.H.V.E. Journal Section, Heating, Piping A Air Conditioning, November 1937, p. 700). Air Discharge from Narrow Slots, by F. F. Stevenson (Heating, Piping <fc Air Conditioning, May 1941, P 308, and June 1941, p. 368. Discussed by J.-'R. Fellows and D. W. Nelson, loc. eit., September 1941, p. 558 and 559). ... ' Vertical Air Distribution in Tall Buildings, by Sturm (Heating, Piping <fc Air Conditioning, June 1947, p 69 aEnfdficSieepntteAmibreDr 1is94tr7i,bpu.ti9o3n). in Theatre. (Heatim, Pip* ing and Air Conditioning- , Question of the Month- August 1947, p. 107; September 1947, p. 113; November 1947, p. 103). Test Every Air Conditioning System, by L. T.-Avery and J. Black. (Heating and Ventilating, June 1948 p.B9a6l)a. ncing an Air Conditioning System, by L. R. Phillips. (Refrigerating Engineering, July 1950, p. Ill)What is a Draft? (Heating. Piping dt Air Conditioning, Open for Discussion. May 1951, p. 67, July 1951, P 71, Sept. 1951, p. 69, Seven Questions January 1952, on Ducts and Gp.ri1ll1e3s,.M(Harecahti1n9g5,2P, pip.i7n3g).& Atr Conditioning, Question of the Month. Maf 1952A, ipr.D1i0s6traibndutJiounlyS1t9u5d2ie. ps,, b1y11R). . V. Martelli and H. O. Scarlett (Heating- , Piping & Air Conditioning, No* vember 1952, p. 77. Discussed by W. O. Huebner, loc. cit. Jan. 1953, p. 119 and.by the Authors, March 1953 o. 85). .. CHAPTER 32 AIR DUCT DESIGN Pressure Losses, Friction Losses, Circular Equivalents of Rectangular Ducts, Dynamic Losses, Pressure Loss in Elbows, Losses Due to Area Changes, Pressure Changes, Duct Design Methods and Examples, Duct Construetion Details, Heat Losses from Ducts, Maintenance AIR ducts for the transmission of the air in forced air heating, veritilating, cooling, or air conditioning systems must be carefully designed for functional as well as economical reasons. The design should be based upon the fundamental laws of fluid flow in pipes, and should take into ac count recent analytical and experimental studies which complement and substantiate the fundamental laws. The basic equations of the flow of fluids will be found in Chapter 4, Fluid Flow. " PRESSURE LOSSES Air ducts impose resistances to air flow which must be overcome by pressure differences resulting from the expenditure of energy in maintaining the flow. Since the flow of air, in ventilating and air conditioning work, takes place under very small pressure differences, the assumption that the gas density remains constant throughout the flow will cause only a negligi ble error. It is therefore possible to use the equation for incompressible ' fluids (liquids) for the flow of air in a duct, instead of the complicated thermodynamic formulas for air discharge under conditions of adiabatic flow, which would be necessary if pressure differences were large. A reasonably precise estimate of the flow resistances offered by the system is essential for satisfactory duct design. The theoretical resistance of an air handling system can be computed from the methods and data given in this chapter. The actual resistance for any given installation, however, may vary considerably from the calculated resistance because of variation in the smoothness of materials, the type of joints used and the ability of the workmen to manufacture the system in accordance with the design. It is best to select fans and motors of sufficient size to provide a factor of safety. Dampers should be installed in each branch outlet to balance the system. The drop in pressure in air transmission systems is due to friction losses and dynamic losses. Pressure increases and decreases may also be caused by changes in duct areas, with resulting conversion of velocity pressure to static pressure, and vice versa. The friction losses for turbulent flow (which occur in all practical air flow problems) are due to the friction of air against the sides of the duct, and to Internal friction between the air molecules. The dynamic losses are caused by changes in the direction or in the velocity f air flow, and may be caused by changes in size and shape of the cross section of the duct, by bends (elbows), and by obstructions to flow offered oy dampers. FRICTION LOSSES * Pressure drop in a straight duct is caused by surface friction, and this 'Action loss is most readily calculated by means of the Air Friction Charts, 697 698 CHAPTER 32 1954 Guide Air Duct Design 699 CU FT OF AIR PER MINUTE CU F T OF AIR PER MINUTE Fig. 1. Friction of Air in Straight Doers For Volumes of 10 to 2000 cfm (Based on Standard Air of 0.075 lb per cu ft density flowing through average, clean, round, galvanized inetfll ducta having approximately 40 joints per 100 ft.) No safety factor included. Caution: Do notextropo^a below chart. Fig. 2. Friction of Air in Straight Ducts For Volumes of 1000 to 100,000 cfm (Based on Standard Air of 0.075 lb per cu ft density flowing through average, clean, round, galvanized metal ducts having approximately 40 joints per 100 ft.) No safety factor Included. Figs. 1 and 2, covering volume ranges of 10 to 2000 cfm, and 1000 to 100,000 cfm, respectively. These charts were developed by the A.S.H.V.1B. Re search Laboratory.1 They do not include any safety factor. The charts, Figs. 1 and 2, were constructed from the basic flow equation for the pressure loss in circular ducts (see Chapter 4): 700 CHAPTER 32 1954 Guide A,= (1) where hi = head loss due to friction, in feet of fluid flowing. 1 = length of conduit, feet. D = inside diameter of conduit, feet. v = mean fluid velocity, feet per second. g = acceleration due to gravity, 32.17 feet per (second) (second). / = a non-dimensional friction coefficient, which for ventilation work depends . upon Reynolds Number and the relative roughness of the conduit. Appro priate values of / were taken from the work of Moody! where e = 0.0005 ft. : See Chapter 4, Fig. 4, Relation Between Friction Factor and Reynolds Number. The air friction chart is based on standard air3 with a density of 0.075 ' lb per cu ft, flowing through average, clean, round, galvanized metal ducts having approximately 40 joints per 100 ft. Fig. 1 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. For the " average application, values from the charts should have sufficient preci- . sion, without corrections, for any air temperature from 50 F to 90 F, for.any relative humidity, and for any normal variation in barometric pressure. For widely varying air pressures or temperatures, or for unusual duct con ditions, the friction values obtained from the chart should be corrected.4. For ordinary ventilating work, friction may be assumed to vary directly. as the density without serious error, and therefore ' where ho = friction loss under actual operating conditions, any consistent units. h, = friction loss under standard conditions, any consistent units. Po = density of air under actual operating conditions, any consistent units. p = density of air under standard conditions, any consistent units. For ducts of other than standard sheet metal construction, correction factors may be obtained from Fig. 3.4 The correction factors shown in Fig. 3 were computed for the values of e, the roughness in feet, shown in Table l.4 The correct friction loss for such ducts may then be determined by multiplying the losses obtained from Figs. 1 and 2 by these factors. Examples 1 and 2 illustrate the use of Fig. 2 to determine friction loss, and the use of Fig. 3 to apply a correction for roughness. ' Example 1: Determine the friction loss when circulating 10,000 cfm of air through 75 ft of 24 in. diameter galvanized duct. Solution: Find 10,000 cfm on the left scale of Fig, 2 and move horizontally right to the diagonal line marked 24 in. The other intersecting diagonal shows that the velocity in the pipe is 3200 fpm. Directly below the intersection it is found that the friction per 100 ft is 0.50 in.; then for 75 ft the friction will be 0.75 X 0.50 = 0.38 in. In a like manner, any two variables may be determined by the intersection of the lines representing the other two variables. Air Duct Design 701 joints per 100 ft > find____t_h__e_ nttovMtaUl Ufr.iction. ' Solluuttii,on: On Fig. 3 find (by interpolation between 12 in. and 40 in. pipe) tIn intersection of the 24 in. very rough pipe line and the 3200 fpm velocity ordinate and at the left margin read a correction factor of 2. The friction loss in the rougl duct is therefore 2 X 0.38 = 0.76 in. _______ --. wva V An air handling system is usually sized first for round ducts. Then, rectangular ducts are desired, their sizes are selected to provide air carr mg capacities equivalent to those of the round ducts originally selected A recent comprehensive study at the A.S.H.V.E. Research Laboratoi proved that for most practical purposes rectangular ducts of aspect rati not exceeding 8:1 will have the same static friction pressure loss for equ Table 1. Values of Roughness < fob Different Pipes* Pipe ^rewn Tubing ^ew Steel or Wrought Iron Pipe... a*vanized Iron Average Concrete Average Riyeted Steel computing values for Fig. 3. Degree 07 Roughness Very smooth Medium smooth e Roughness in Feet ------------------------ -- 0.0000015 0.00015 Medium rough 0.0005 0.003 0.01 702 CHAPTER 32 1954 Guide lengths and mean velocitiesof flow as a circular duct of the same hydraulic diameter.; When duct sizes are expressed1 in terms of hydraulic diameter, and when equations for friction loss in: round and rectangular ducts are equated, for equal capacity and equal length* air equation giving the circu lar equivalent of a rectangular duct is obtained5 (Equation 3). where (o6) dc = 1.30 (a + 6)-> 1.30 (g&)* (a + by (3) a -- length of one side of rectangular duct, inches. (Other side is b.) b = length of one side of rectangular duct, inches. (Other side is a.) dt = 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 capacity for aspect ratios not greater than 11.7 :1 based on Equation 3.6 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 circular equivalent of an 80 x 24 in. duct is required, it will be twice that of 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. Dy namic losses generally are greater with decelerating flow in duct enlarge ments than with accelerating flow in reducing fittings. Although dynamic Table 2. Circular Equivalents op Rectangular Ducts for Equal Friction and Capacity ' Dimensions in Inches Rectan 4.0 4.5 5.0 5.5 6.0 6.5 V3 75 8.0 85 9-0 9.5 1 gular Duct 3.0 3.5 4.0 4.5 5.0 5.5 3.8 4.1 4.4 4.6 4.9 5.1 4.0 4.3 4.6 4.9 5.2 5.4 4.2 4.6 4.9 5.2 5.5 5.7 4.4 4.8 5.1 5.4 5.7 6.0 4.6 5.0 5.3 5.6 6.0 6.3 4.8 5.2 5.5 5.9 6.2 6.5 4.9 5.3 5.7 6.1 6.4 6.8 5.1 5.5 5.9 6.3 6.7 7.0 5.2 5.7 6.1 6.5 6.9 7.2 5.4 5.8 6.3 6.7 7.1 7.4 5.5 6-0 6.4 6.9 7.3 7.6 5.6 6.1 6.6 7.0 7.4 7.8 5.76.3 6.^ 7.2 7.6 8.0 Side Rectan 10.0 105 111 115 13.0 12.5 13.0 135 14.0 145 155 155 15 gular Duct 3.0 3.5 4.0 4.5 5.0 5.5 5.7 6.3 6.8 7.2 7.6 8.0 5.9 6.4 6.9 7.4 7.8 8.2 6.0 6.5 7.1 7.5 8.0 8.4 6.1 6.7 7.2 7.7 8.1 8.6 6.2 6.8 7.3 7.8 8.3 8.7 6.3 6.9 7.5 8.0 8.4 8.8 6.4 7.0 7.6 8.1 8.6 9.0 6.5 7.1 7.7 8.2 8.7 9.2 6.6 7.2 7.8 8.4 8.9 9.4 6.7 7.3 7.9 8.5 9.0 9.5 6.8 7.4 8.1 8.6 9.1 9.6 6.9 7.5 8.2 8.7 9.3 9.8 7.< 7A 8-* 8.* o\ 9.1 Air Duct Design Dimensions in Inches 703 U-) .t.h.ocsaeircanuoswe,dtboyr ccohnanvgeensieinncdeirtehcetyiona,,roe_f_dt_hivei.d.d.euudciritnaatota,butewvnuodasugyeanonecdcrabulrpacienladcshseess,: (2) those caused by changes in cross-seciional area of the duct at transi- Hynamic losses vary substantially as the square of the mean velocity of !; h, :: 'i i. i' ; 1:1 . jh 1 vi CHAPTER 32 1954 Guide I ozoo < o a z< oz po 2 j Ea> Q a gig 20 p co B tf 03 <A S 1. > | to lf 1 | .an- or, oeoo arsgs Sgg SSSS SSSS SSSS SSS ss ss tQtPbr OB OB ooo 0900 0 0 0 0f-oo C o>-->e> OBB 03ono voowoo ooo aNs oasooooo -- sbo 00 00 00 00 00 ofn. o -- eGOeo vOO iOnO OOr- ooCoO oa oo . <e> . 2 g --------------------------------------------- ' s . . SSSf: sess SSSS SSS . HPSS gESg SSSS SSS ggss gspp SSSS RSSKS SSS co co co co co co eoeoeo^ -- ci co -a* MO t-oo ob co oo ooor* cor^o -- -- ir cd if I = r*r r- r- r- r-- ,w. CSS r- f* 62 - . . s ------- -----------------------* ---------- 00O* ' --------------------------------- " . -- '' ----------------------- --------------c* ' to oooo oooo oor*N r-r*t--r- ~ 00900 N OOC cot- &*> i 03^09 toru^soVd3 o-c s g f<co ErSb S gr-Cr-rr-Sr- ?tT___| 2 2 ^eoo* --co to^es eieo voon <O--" w mv SSS&S oSwSSi-ri^- ' 1 ! co co eo coeoeoo* --oo oo r- co -t-BO co r- SSS SSSS isSSS SSSS SSSS SSg 4 4---- C C aoOr-C0 iOHO --OB 5 2 3 3S K S S SSSS ggSS`SSSS SSteB ... 00O SS._ cs> aao ooor-r- ->r p 55S SS SSSS SSSE SSSg SSSS SS bAo -w O*hqm <eAeh * rtesii-> a'Jo' o -- oo^e -- co-<j* ooocb aieno d*-C tiOJa"5oS3 e*D COOC* 2(c^oo bco^ 3ocpbcb Qwoi ~ HZ 3 > 5 w<7 es 36 y 5 C<D .705 the air, and are therefore conveniently expressed as a fraction of the velocity head; .. .......... and for standard air Hr-c(^)' \4005/ where fw = dynamic pressure loss, feet of fluid flowing. Hr = dynamic pressure loss, inches of water. v = velocity of fluid, feet per second. (4) (5) 2j = the velocity pressure corresponding to the mean velocity of flow, feet of fluid flowing. V = mean velocity of standard air, feet per minute. : C = an experimentally determined constant (dynamic loss, coefficient). . It can be seen from Equation 4 that the dynamic loss coefficient is. inde pendent of both density and the units used, and that it represents the dumber of velocity heads lost at the conduit transition or bend. Values of the dynamic loss coefficient for various duct elements are sometimes tabulated^*. *>8 though it should be kept in mind that absolutely reliable dynamic loss coefficients have not-yet been fully established for all duct elements. :. Fig. 4, which shows the relation of velocity pressure to velocity for stand ard air (V = 4005VH,), can be conveniently used to find the total. dynamic Pressure loss for any duct element-with known dynamic loss coefficient C. ^coefficient is nearly independent of the air velocity and the roughness ffiret walls; therefore dynamic losses cannot theoretically be computed as faction losses. For duct components where intense eddying flow is not 706 CHAPTER 32 1954 Guide appreciable, as in elbows of good design, it is customary to include the dynamic loss with the friction loss, thereby facilitating design calculations. PRESSURE LOSSES IN ELBOWS It is convenient to express the combined dynamic and friction losses due to an elbow as equivalent to the loss in a length L of similar straight duct. A recent A.S.H.V.E. survey9 of available data has indicated that this method of expressing the loss is justified for design purposes, owing to the relation of the loss to the corresponding friction factor, /. Fig. 6 gives the additional equivalent length of duct in terms of widths 1-V for elbows in rectangular ducts; Fig. 6 gives the equivalent length in terms Air Duct Design 707 rr ru , the aspect ratio is = ^ = 4.0; Fig. 5 gives (L/W), = 6, so Li = 6 X 6/12 = 3 addi tional equivalent feet. . The total length of the straight runs from A to D is 1 = Ia-b + 1b-c + Jc-d = 7 + 20 + 5 = 32 ft and the additional equivalent length due to the elbows is L -- L, + Lt = 23 + 3 = 26 ft. Thus the equivalent length of the system from A to D is 1 + i -- 32 + 26 = 58 ft of 6 by 24 in. duct. The diameter of a circular duct,- equivalent in friction and capacity to this rec tangular duct, is 12.4 in. as given by the table of circular equivalents. Table 2. At a delivery rate of 2000 cfm, the A.S.H;V.E. Friction Chart, Fig. 2, gives a loss of 0.6 in. of water per 100 ft of 12.4 in. diameter duct. Thus the loss; from A to D is 0.6 X 58/100 = 0.348 in. of water. The use of elbows of radius ratio, R/W = 1.5, is considered good practice with respect to both installation and operation. In a given rectangular duct 6 by 24 in., for example, the additional equivalent length L necessary to represent the elbow loss will generally be greater for a flat bend where the Fig. 5. Loss in 90-Deg Elbows of Rectangular Cross-Section of diameters D for round ducts. When these curves for additional equiva-_ lent length are used, the straight lengths of duct between elbows should be measured to the intersection of their center lines. The data of Figs. 5 and 6 may be readily converted9 to the loss as a percentage of the velocity head-. Example S: (Use of Fig. 5 for the calculation of elbow losses.) Given the portion of a duet system shown in Fig. 7, it is required to determine the pressure loss between points A and D. Air at standard conditions is being supplmo at the rate of 2000 cfm in a 6 by 24 in. galvanized duct of average construction. E*' bows No. 1 and 2 have centerline radii of 18 and 9 in., respectively. Jg . . Solution: For elbow No.. 1 the radius ratio is jwjt1, = 2;-4 == 0.75 and the. aspect ratio,t is ^ = 0.25. The additional equivalent length for elbow No. 1 in terms of ^ is obtained from Fig. 5: (L/W)i = 11.5. Thus Li = 11.5 X 24/12 = 23 additional equivalent fee t. Similarly for elbow No, 2, the ratio radius is Rt = 9g = 1.5 an?j 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 presently available for losses in compound bends,10,11 where two or more elbows are close together, do not warrant refinement of design calcu lations beyond use of the sum of the additional equivalent lengths L for the individual elbows. Where angles of other than 90-deg bend are en countered, the loss may be considered as directly proportional to the angle of bend. Losses11 for elbows discharging air directly into a large space are higher than those indicated in Figs. 5 and 6 for elbows within duct systems. Data19 for losses at branch take-offs are at present quite meager. An +-S.H.V.E. cooperative investigation is underway for the purpose of obtain- In8 more data on losses in typical take-off fittings. Turning vanes may be advantageously employed in elbows, both to re duce the pressure loss and to provide a more uniform velocity distribution downstream from the bend. Vanes and concentric splitters are particularly recommended where miter elbows are used, because even the simplest vane 708 CHAPTER 32 1954 Guide Fia. 7. Portion op Duct System for Example 3 forms will produce a substantial saving in pressure loss. The addition of vanes or splitters divides an elbow into parallel channels, each having more favorable radius and aspect ratios than the original elbow. Values of addi tional equivalent length L, for elbows of square cross-section having various' vane forms and combinations, may be found from Table 3-in which values of L/W are shown. LOSSES DUE TO AREA CHANGES . Area changes in ducts, generally unavoidable, are necessitated frequently.;; by the building construction or changes in the volume of air carried. Ex-1 perimental investigations14'16 of pressure changes, and pressure losses at*: changes of the area of duct cross-sections, indicate that the excess pres sure 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 contracted, but the air stream continues to converge beyond the edge oh the contraction arid reaches a minimum at the vena contracta. This con- ,* traction of the air stream is shown in Fig. 8. For contraction, therefore,-, the dynamic loss is-caused by expansion from the vena contracta to the full'/ area following the contraction. Enlargement in area may be consider!? as a special condition of general expansion following contraction. Fig,1? illustrates (a) abrupt enlargement and (b) abrupt contraction. 1T : For a sudden symmetrical enlargement, a theoretical expression for .the loss is Fio. 8. Air Flow at Abrupt Enlargement or Contraction op Air Stream Air Duct Design or for standard air; .70? where II.- A. \l / 17 \ V= 400355/ V 4005 / (7) K *= pressure loss due to sudden enlargement, feet of fluid flowing. II, = pressure loss due to sudden enlargement, based on standard air, inches of water. - . in Additional Equivalent Duct Length*' b . Additional Equivalent Length L = Duct Width W, in Feet, Multiplied by L/W . Values Shown --iu me uuco uuutj idfli per second* Bt = velocity in the outlet duct, feet per second. Fi = velocity of standard air in the inlet duct, feet per minute. Ft = vejpcity of standard air in the outlet duct, feet per minute. 4i = area of the inlet duct, square feet. .' r= area of the outlet duct, square feet. The loss for a sudden symmetrical contraction, he can similarly be ex pressed as h. \ Aj 2g (8) 710 CHAPTER 32 1954 Guide where . .f kc -- pressure Joss due to sudden contraction, feet of fluid flowing. > V* = the velocity at the vena`contracts, feet per second. A't = the area of the vena contracta, square feet. Introduction of the contraction coefficient a --A and the loss "'' coefficient A1. - - = -- 1^ in Equation 8 gives (with A2 X Vi -- At X fi): or for standard air: = C --2g m where \ ' ; He == pressure loss due to sudden contraction, inches of water. V\ ^ velocity of standard air in the inlet duct, in feet per minute. > Values of a and C for sharp corners for increasing ratios of A2/A, are: given in the following table: ; .: ; AifAi a c 0.01 0.1 6.2 0.4: 0.6 0,8 1.00 0.6: 0.61 0.62 0.65 . 0.7 0.77 1.00 . 0.44 0.41 0.37 0.29 0.19 0.09 0:00 For discharge to atmosphere from a pipe, C = 1.0 in Equation 10. For a gradual enlargement, Equation 7 changes to where Hlc = pressure loss due to gradual enlargement, based on standard air, inches of water. Ci = coefficient of loss, dependent upon the total angle included between the sides of the duet. Values for C, are given in the following table: Total. Included Angle. Deqbbbs c, 67 0.20 | 0.15 10 0.16 20 0.35 30 0.65 40 0.80 60 60 5^0.92 Air Duct Design 711 Pressure losses for various duct transitions and area changes have been determined experimentally, although the available information is generally restricted to symmetrical area changes.8, 7-1416,16,17 PRESSURE CHANGES The fundamental energy equation for standard air flow in a horizontal duct can be written18 ' Hi + + Loss of pressure (head), inches of water (12) where Hi and Hi = the static pressure (head) at two given points (1) and (2), inches of water. . the velocity pressure (head) at the same points, inches of water. Equation 12 states that the mechanical energy at a given point (1) must be equal to the mechanical energy at another point (2), plus any dissipa tion of mechanical energy to internal energy (loss of: pressure). Equa tion 12 is valid only if no work is done by or upon the air between the sections (1) and (2), and if there is no heat transfer to or from the air. In Equation 12, H is a measure of the potential energy and l(40V05V/ a measure of the kinetic energy or energy of motion. The sum of static pressure and velocity pressure is called total pressure, and is^a measure of the total energy. . Static pressure and velocity pressure are mutually convertible, that is to say, static pressure may be converted into velocity; pressure, and vice versa. Every change in the cross-sectional area of a duct results in such a conversion of energy and is always accompanied by some loss in effi ciency, or loss in total pressure. ' In the final analysis of pressure losses in ducts, dynamic losses are due to accelerations and decelerations of the air stream as a whole. In a con verging duct, the air velocity will be accelerated; some pressure head will be converted into velocity pressure. This conversion is generally a stable and efficient process, the energy losses are small, and there is no eddy formation. In an expanding duct section, on the other hand, the air will be decel erated and an opposing pressure gradient be required to reduce the velocity. If the angle of divergence is appreciable, the flow becomes unstable, there is danger of separation of the flow from the duct wall, and large energy esses and eddy formation are possible.19 In order to keep losses in an expanding duct section to a minimum and h) convert the velocity pressure efficiently into static pressure, the angle of divergence should be kept small.70 Theoretically, it might seem possible 10 increase the duct area so gradually that the reduction in velocity and accompanying loss of velocity pressure would occur reversibly, and thus Permit 100 percent conversion to static pressure. Such an ideal applica- fln of the principle of static regain in duct design is, of course, impossible *or various reasons71 such as: the necessity of using sections of uniform diameter because of cost, the need for using ducts of dimensions varying 1111U11 inches, the changing of duct sizes mainly at branch connections, and 712 CHAPTER 32 1954 .Guide the-inevitable loss due to turbulence. The principle of static pressure regain is, however, of importance in the economical design of duct systems'.- Fig. 9 shows the application of static pressure regain to a simple fan and " discharge duct.22 The fan in the upper part of the figure has a free inlet and discharges air through a straight duet, the diameter of which is equal to the fan outlet. The total pressure which must be provided by. the fan is therefore the sum of the pressure that is necessary to overcome the fric tion in the duct (no dynamic pressure loss), plus the velocity pressure which, in this case, is the same at any location along the length of the duct. In arrangement B in the lower part of Rg.~9, a diverging section, with after section, has been added to the straight duct. The velocity in the diverging section is therefore decreased, and velocity pressure converted Arrangement A M 4_ /Velocity Pressure >y ofthe Air Leaving the System. Atmospheric Pressure Arrangement B T After Section ^Expanding Section t-t{Decrease in'TotaiPressure . I V Due to Static Pressure Regain ^SLPressuc^ cAtmospheric Velocity Pressure ofthe AirLeaving the system^ ^Static Pressure Re gain in Expanding Section. . Fig. 9. Application of Static Pressure Regain to a Simple Fan and Discharge Duct - - . ' )-! into static pressure before the air is released to the atmosphere. It can be seen that in case B, the total pressure at the fan outlet is less than"in case A, and thus a saving in horsepower can be effected. The regain in static pressure h, in an abruptly expanded section is the difference in the velocity pressures of the small and the large duct, minus the dynamic pressure loss (Equation 6): r _ rfa ~ *' = l2g - 2g\ [ 2g _ (13) or simplified lit -- J Ihfa -- tfr) h, = g g where h, = regain in static pressure, feet, of fluid flowing. (14) J. ilf Air Duct Design 713 Pi and Pj = pmeerasnecvoenlod.cities in inlet and outlet duet sections, respectively, feet The static pressure regain in a gradually expanding transition, followed by an after section, may be expressed as - j. _ f. b_] rcifa _ ' 1*9 2g\ |_ 2g J (15) or hr = !-- ci(i -- Pi)1 2g (16) where c, = an experimentally determined regain constant depending on nature of con struction. . Curves have been developed showing the static pressure regain, and the theoretical efficiency of conversion in abrupt expansion, and in diverging sections in smooth circular ducts.16-16 ...... DUCT DESIGN The discussion of duct design in this chapter refers to ducts in fan sys tems for central heating, ventilating and air conditioning. Additional data for heating-ducts used in residences are to be found in Chapter 19 (Gravity Warm Air Systems) and Chapter 20 (Forced Warm Air Systems). The design of ducts in industrial exhaust systems is discussed in Chapter 46. The following general rules should be followed in design: 1. The air should be conveyed as directly as possible at the permissible velocities to obtain the desired results with greatest economy of power, material, and space. 2. Sharp elbows and bends should be avoided. Splitters and turning vanes should be Used to reduce the elbow or outlet pressure loss. 3. Diverging transformation pieces should fie made as long as practicable. As shown in the section on area changes, losses in sudden enlargements are high, and abrupt enlargements should be avoided. The included angle of divergence for enlargements should not exceed 20 deg. tosses in contractions are low, but the in cluded angle of convergence should not be larger than 60 deg. ,, 4. Special care should be taken to avoid restriction of flow in. elbows or trans formation pieces. : . 5. Where the greatest air carrying capacity per square foot of sheet metal is de- s,red, rectangular ducts should be made as nearly square as possible. Aspect ratios Poster than 10 to 1 should be avoided. . 6. Duets should be constructed of smooth material, such as steel, or aluminum sheet metal. For ducts made from other materials, for example masonry, proper allowance for the surface friction coefficient should be made. . Procedure for Duct Design ' The genera] procedure for design is outlined as follows: of d *-udy the plan of the building and draw in roughly the most convenient system : ,cfa taking cognizance of the building construction, avoiding all obstructions steel work and equipment, and at the.same time maintaining a simple design. " Arrange the positions of duct outlets to insure the proper distribution of air. suit' divide the building into zones and proportion the volume of air necessary for ach zone. ce(|.' Determine the size of each outlet, based on the volume as obtained in the pre- diffi 11 paragraph, for the proper outlet velocity and throw. In case of some Ceiling users, determine size of outlet for proper throat velocity and radius of diffusion. 714 CHAPTER 32 1954 Guides 5. Calculate the sizes of all .main and branch ducts by one of the three methods of sizing air supply systems in common use, the velocity reduction method, the equal friction method or the static regain method. 6. Calculate the losses for the duct offering the greatest resistance to the flow of air, using the A.S.H.V.E. Friction Charts, Figs. 1 and 2, and the other data given in this chapter. .. Recommended. Design Velocities The air velocities given in Table 4 have been found to give satisfactory results in engineering practice. Where the higher velocities are used, the ducts should be cross-broken to prevent breathing, buckling or vibra tion, and should be constructed of heavier gage metal. At the higher velocities, it is particularly important to design the ducts for minimum resistance. Since high velocities at one point offset the effect of proper de sign in all other parts of the system, emphasis should be placed on the im- Table 4. Recommended and Maximum Duct Velocities Recommended Velocities, ppm Maximum Velocities, fpm Designation Residences Schools, Theaters, Public Buildings Industrial Buildings Residences Schools, Theaters, Public Buildings Industrial Buildings Outside Air Intakes* Filters* Heating Coils* Air Washers Suction Connections Fan Outlets Main Ducts Branch Ducts Branch Risers 500 250 450 500 300 500 500 350 600 800 300 500 900 350 600 1200 350 " 700 500 500 500 700 800 1000 1000-1600 1300-2000 1600-2400 500 900 1700 500 500 1000 1400 1500-2200 1700-2800 700-900 600 500 1000-13001200-1800 600-900 1. 800rl000 600-700 800 800~1200'll00-1600 1300-2200 700-1000! 800-1300 1000-1800 650-800 800-12001000-1600 These velocities are for total face area, not the net free area; other velocities in table are for net free portance of air velocities, elbow design, location of dampers, fan connec tions, grille and register approach connections, and similar details. For in dustrial buildings, noise is seldom given much consideration, and main duct velocities as high as 2800 or 3000 fpm are sometimes used, but when these velocities are used due consideration should be given to duct design, resis tance pressure, fan efficiencies and motor horsepower. For department stores and similar buildings, 2000 to 2200 fpm are sometimes used in main ducts where noise is not objectionable. , Where high velocity diffusing outlets are used, the duct velocity should be, if possible, equal to, or somewhat lower than the throat (neck) velocity of the diffuser, in order to utilize the effect of higher static pressure in the duct for equalization of air discharge. The velocities in main ducts, and particularly in branch ducts-and branch risers, should be correlated to the throat (neck) velocity of the air outlets, and manufacturers' data should be consulted for permissible throat velocity for the particular type of application. If it is necessary to use a duct velocity that is twice the velocity for &n outlet mounted on the side of the duct, a collar with directing vanes should be used to straighten the flow of air from the outlet. Sometimes it ^ desirable to mount the outlet flush with the side of the duct, in which case Air Duct Design 715 the duct velocity should be kept below twice that of the outlet velocity, and even then an outlet larger than normally required should be used, as the entire outlet area will not be effective. Manufacturers' selection tables base sizing of outlets on required volume of air, temperature differential, and distance of throw or radius of diffusion. In following their recom mendations, maxima should be avoided. See Chapter 31 for a discussion of air outlets. DESIGN METHODS The design of the air transmission system is generally the last step in the design of the heating, ventilating or air conditioning system, but it should always be kept in mind that the type of air transmission used will, to some extent, depend on the type of equipment used, as well as on the purpose of the system. Various factors such as zoning and zone control, and their influence on the transmission and air distribution system, are briefly discussed in Chapter 30 (Central Systems for Air Conditioning). The methods used for the design of duct systems reflect, to some degree, certain developments in the arts of heating, ventilating and air conditioning, and it took a long time before empirical methods gave way to more refined and scientific calculations. Some engineers prefer speed and simplicity to scientific exactness, but experience is then needed and proper judgment must be exercised to prevent mistakes. Both the Velocity Reduction Method and the Equal Friction Method take no account of the static regain resulting from the difference between the velocity of fan discharge and velocities of pipe discharge, and are therefore, to some degree, approximate methods. However, they are more easily applied than the static regain method which is based on proper theory, but is subject to an assumption (based on tests) regarding the efficiency of conversion from kinetic energy to static regain. 1. Velocity Reduction Method When this method is used, arbitrary velocities for the various sections of the ducts are selected, with the highest velocity at the fan outlet, and lower velocities down the run as various branch ducts are taken off the main duct. Since the quantities of air that are to be delivered through each section of the duct are known, the area of each duct section can be easily determined by using the formula: where A = duct area in square feet. Q* = air quantity in cubic feet per minute. Vm = air velocity in feet per minute. To find the total static pressure against which the fan must operate, the static pressure loss of each section is calculated separately, and the total [oss found by adding the individual losses of the sections of the duct which uas the highest resistance. This may be the duct with the longest run, out not necessarily so. The velocity method has the advantage that the duct area can be deter mined very easily. It should be used only for simple layouts. The air velocities given earlier in this chapter are helpful in choosing proper ve- 716 CHAPTER 32 1954 Guide locities. Balancing is obtained by use of dampers. The method is illus trated in Example 4- ,/ sicicnw-*.A.... Ol - sec-0-- O sec-c O1 scc-o - O o-rr so-rr 2pt 20-PT Fig. 10. Duct Layout fob Example 4 Example 4: (Velocity Reduction Method). A duct layout is shown in Fig. 10. The fan delivers 8000 cfm. Four outlets deliver 2000 c!m each. Find duct dimen sions and total pressure loss. Solution: Select velocity for Section A (2200 fpm) and reduce velocity arbitrarily along run. Find duct areas by using Equation 17. For selection of circular equiva lents of rectangular ducts refer to Table 2, and for determination of friction loss in duct refer to Fig. 2 (See Example 1). Results are tabulated in Table 5. , Section A B C D Table 5. Tabulation op Results (Example 4) Aix Volume cfm Velocity fpm Area sq ft Area sq in. Duct Size ' DlAM in. in. Frict per 100 rr in. HiO Frict' Loss in. HiO 8000 2200 3.64 524 26 x 20 24.8 0.25 0.10 6000 2000 3.00 432 22 x 20 22.9 0.23 0.05. 4000 1800 2.22 320 20 x 16 19.5 0.24 0.05, 2000 1600 1.25 180 12 x 16 15.1 0.24 0.05 Total resistance, 0.25 2. Equal Friction Method When the equal'friction method of design is used, the duct system is designed for equal friction per foot of length. This prevents one section of the duct from having an excessive resistance compared with another,) The usual procedure in this method is to select the main, duct velocity to be consistent with good practice from a standpoint of noise for a particular type of building. This velocity should be less than the fan outlet velocity, All ducts are then sized for equal friction per unit length by the use of Figs, 1 or 2 and Table 2. The equal friction method has the advantage of auiof matically reducing the velocities in the various sections of the system, and.; also of allowing a quick check of the total duct resistance. In cases where the fan or factory assembled air conditioning unit can; operate against only a limited external resistance, it is necessary to divide; the permissible total resistance by the total equivalent length of the longest or most complicated run of duct to determine the design resistance per, 100 ft, and then to size all ducts at this resistance value. This will autoj matically determine the duct velocities and give the desired total duct resistance. A further refinement, which is sometimes used in large systems, is to size each branch duct so that it has a resistance equal to the resistance- of the main system at the point of juncture. Even when this refinement is added, regulating dampers are recommended in each branch. , ' Example S: (Equal Friction Method). A duct layout is shown in Fig. 11... fan delivers 2500 cfm. Outlets No. 1 and 2 deliver 750 cfm each and outlet No; 3'd*j- livers 1000 cfm. Trunk velocity is assumed as 1500 fpm; the area will be 1.67 squt- (240 sq in.): and the size will be 20 x 12 in. Determine sizes of ducts for sectioift B, C, D and E and find the total pressure loss. ; !vri Solution: The equivalent round diameter of a 20 x 12 in. rectangular duct in. (from Table 2). Referring to Friction Chart, Fig. 2, a volume of 2500 cfm tbroug,^ Fia. 11. Duct Layout fob Example 5 a 16.8 in. duct gives a resistance of 0.2 in. per 100 ft. The amount of air to be handled by each section is known, and the corresponding round duct sizes with equal pressure drop for these values can be located on the 0.2 in, friction line. The equivalent rec tangular duct sizes are then selected from Table 2. . Results are tabulated in Table 6. Table 6. Tabulation op Results (Example 5) Section A B C D E Ala Feiction Volume pee 100 nl Diam. dm in. 2500 0.2 16.8 750 0.2 10.7 1750 750 1000 0.2 0.2 0.2 14.8 10.7 12 Veloc ity fpm' Rectan gular Duct in. Friction PER 100 FT. in. Diam. in. 1620 1190 1400 1190 1300 20 x 12 10 x 9 15 x 12 10x 9 10 x 12 0.2 0.286 0.2 0.4 0.2 17 10 14.5 9.8 12 Veloc ITY 1pm RectanGULAfi Duct 1600 1350 1450 1350 1300 20 x 12 10 x 8 15 x 12 10 x 8 10 x 12 The total pressure loss in the longest run is the friction loss in Sections (A +C + E), plus the loss in one elbow and the loss through the outlet (3). The additional pressure loss in the elbow will be assumed as ^ = 12 (Fig. 5); thus, the additional equivalent length of duct is 10 ft, and the design loss will be 0.02 in. Friction loss (A -F C -F E).. 0.12 (Duct length = 20 ft -F 10 ft -F 15 ft + 15 ft) Elbow loss.................................. 0.02 Loss through outlet................ 0.12 Total pressure loss in duct. ................................--= u0.Z.2iU61iUn.. - The pressure required at the beginning of the main run is therefore 0.26 in. The fan selected for the duct system must not only deliver the required volume of air against this Iosb, but also against the losses in all air conditioning apparatus such as washers r spray chambers, heating or cooling coils and filters. The static head required of the fan for the usual air conditioning installation is between 1 and 1.5 in. of water. About one-third of this represents losses in the duct system. The losses in the air conditioning apparatus can be obtained from manufacturers' catalogs. Resizing of Ducts , In order to equalize the pressure drop in the system, the following addi tional procedure is recommended : Assume AH,, AH*, AH, to be the total pressure loss through ducts (1), (2) and fh ' rf' Tt" r'> r<>> r` ti'e friction losses in the straight sections of the system; it*,, ,, r tae elbow losses, and r,, r,, r, the loss through the outlets. Then, . AH, = r + n> + 2rbe -F r, , , AHt = r. -F rc -F rd -F ra. F n . If AHi = r + r, F r, F I F r, AH, = AH, = AH, = AH n, + 2n = AH - r -- n re -F rd. = AH -- r -- r. -- r. 718 CHAPTER 32 1954 Guide'll or, using the values from Example 5: rb + 2rb. = 0.26 - 0.04 - 0.12 = 0.10 in. ra + rdb = 0.26 - 0.04 - 0.02 - 0.12 = 0.08 in. The loss in the elbows will be assumed to be ^ = 12 or 10 additional equivalent feet, the friction loss of head per 100 equivalent ft is then for duct (1) 0.10 = 0.286 in. 0.15 + 2X0.10 for duct (2) 0.08 0.4 in. 0.10 + 0.10 Using Friction Chart Fig. 1, the duct diameter of Section B, to carry 750 cfm witha. loss of 0.286 in. per 100 ft, is found as 10 in., and the duct diameter of Section D, to carry 750 cfm with a loss of 0.4 in. per 100 ft is 9.8 in. Equivalent rectangular ducts are 10 X 8 in., the velocity in both ducts is 1350 fpm. The actual loss in ducts (1) and (2) is: 0.04 + 20 X + 15 X + 0.12 = 0.26 0.06 + 10 X ^ + 10 X ^ + 0.12 = 0.26 For final survey of ducts selected see Table 6 (Tabulation of Results). 3. Static Regain Method . When this method is used, the velocity is reduced at each branch or take-off so that the recovery in static pressure due to this reduction will offset the friction in the succeeding section. This method is based on the convertibility of static pressure and velocity pressure, as discussed in a preceding section on Pressure Changes. If no friction or dynamic losses occurred, the change in velocity head would be completely converted into a regain in static pressure, which for standard air would be: \4005/ \4005/ (18) where , H, = theoretical head recovered (static regain), inches of water. Vi = initial velocity of standard air, feet per minute. . Vi = velocity of standard air after reduction, feet per minute. .~ Under ideal conditions, 0.7 to 0.8 of the velocity head is actually re covered, blit for practical design an average recovery of 0.5 is assumed. The actual velocity head recovered Ht, then becomes ^O.J^Y-f-^Yl [_\4005/ \4005/J (19) The advantage of the static regain method is that it provides a con venient means of designing a long run of duct (or an entire system) so that essentially the same static pressure will be obtained at each outlet. This simplifies outlet selection and system balancing. On large systems or very long runs, where it may not be feasible or economically desirable to design for zero static pressure loss between outlets, the method may be used to size Air Duct Design 719 ducts for a uniform predetermined, loss. This loss or gain is net, that is, it is the friction loss compensated by any static pressure gain made available by a change in velocity. (The latter effect is commonly neglected in the Equal Friction Method.) Charts for the practical application of the principles of static regain to duct design, are presented in Figs. 12 and 13. These charts are based on Equation 19, as applied to rectangular ducts of average construction with dimension ratios of 3 to 1 or less. Note that the gain or loss indicated on the charts is the net gain or loss in the duct section considered (normally uie distance between two outlets); it should not be confused with static Pressure loss per 100 ft, or total pressure loss in the duct. The total loss or gain in the outlet run is the summation of the losses or gains in the suc cessive sections figured. (Losses in outlets, coils, or similar items are 720 LL_jmO-BOWJ LCO-2T CHAPTER 32 1954 Guide A outlet run). An outlet run is typified by Sections C-D-E in Fig. 14. On larger systems several methods of duct sizing may be combined to secure equal or approximately equal pressures at all outlets. Example 6 shows the method of approach as applied to a very small system. As with any other method of duct design, balancing dampers should be installed in each branch, and each outlet should be equipped'with means of regulating air volume. . Example 6: (Static Regain Method). A duct layout is shown io Fig. 14. The fan delivers 8000 cfm. Outlets 1, 2, 3 and 4 deliver 1500 cfm each, and outlets 5 and fi, 1000 cfm each. The operating pressure loss at all outlets is 0.12 in; water. Initial trunk velocity is assumed as 1500 fpm; the area of the trunk duct will then be 5-33 sq ft, and the size will be 48 x 16 in. It is assumed that for this example it is de sirable to maintain a 16 in. depth on all duct sections; Determine the sizes of duct sections B, C, D, E, F and G so that substantially the same static pressure will be obtained at each of the outlets, and find the total pressure loss of the system. figured separately.) The duct length of any section should include the equivalent length of any elbows occurring within the section. The static regain charts are intended primarily for constructions where regain takes place unaccompanied by radical change in direction; thus, in Fig. 14 they are strictly applicable along the main run A to E, and at the junction of Sections F and G, but not at the junction of Sections A &nd F. Although some regain will usually occur at the branch take-off (where velocity is generally reduced), there are so many varieties of elbows .and branch take-off connections, that estimation of an average value of regain would be quite impracticable. . The static regain method finds its widest application in the design of long duct runs containing numerous successive outlets (usually designated the Fro. 14. Duct Layout fob Example 6 Solution: 1. Size Section F by the equal friction method so that it has the same rate of friction loss as Section A. Section A is equivalent to a 29.2 in. round duct (Table 2) and the pressure loss from Fig. 2 is 0.13 in. per 100 ft. For 2000 cfm flowing at this rate of pressure loss, the indicated round duct diameter for Section F is approxi mately 17 in. (Fig. 2). This is equivalent to a 15 x 16 in. duct; which will be used for Section F. The velocity in Section F will be 1200 fpm. , 2. Determine the pressure loss in Section F. Actual length of duct is 10 ft; equiva lent length of elbow take-off is assumed as 10 W, or 12.5 ft. Therefore, the total equivalent length is 22.5 ft. The pressure loss in F = 0.13 in. Xy^y = 0.03 in. water. 3. Using Static Regain Chart, Fig. 13, size Section B for a net pressure loss equal > the loss in F, or 0.03 in. water as follows: The operation is indicated by arrow heads on the dotted line on Fig. 13. On Fig. 13, start at the velocity in Section A (1500 fpm) at left margin. Proceed horizontally > 6000 cfm ordinate, and then run parallel to the curved lines to intersect the di agonal Base Line. From this point, rise vertically to the 0.03 net static pressure loss pne, and from this intersection proceed horizontally to the Air Velocity Base Line, "roceed parallel to curved lines to intersect ordinate for 25 ft equivalent duct length, and then move horizontally to left margin and read the velocity (1500 fpm). Since Section B carries 6000 cfm, the area required will be yj^-jj = 4 Bq ft, and 4he size of duct will be 36 x 16 in. ,, 4. Using Static Regain Charts (Figs. 12 and 13) determine size of Sections C, D, and G, but instead of allowing 0.03 in. net loss,'which was used for Section'B, Proceed from the diagonal Base Line vertically to the no gain or loss diagonal. The Procedure for Section E is shown by the dotted line and arrows on Fig. 12: starting rom 1040 fpm velocity, which is the velocity in Section D. ^hct sizes determined by the given procedure are listed in Table 7 on next page. 722 CHAPTER 32 1954 Guide Section Table 7. Tabulation of Results (Example 6) Air Volume cfm Equiva lent Length ft Velocity fpm Rectangular Duct in. Diam. in. Friction Per 100 IT in. HiO NetPbes- BURE Loes in. HA) A 8000 B 6000 C 4500 D 3000 E 1500 F . 2000 G 1000 40 25 15 26* 15 22.5 15 1500 1500 1300 1040 860 1200 900 48 x 16 36 x 16 31 x 16 26 x 16 16 x 16 15 x 16 10 x 16 29.2 -- -- -- 17. . --- 0.13 -- -- -- --. 0.13 .05 .03 0 0 0 .03 0 : * Includes additional equivalent length of elbow-between outlets 2 and 3, which is assumed as 5.5 W, or 11 ft equivalent length of duct. (Based on 3000 cfm at estimated velocity of 1100 fpm).. - . 5. Total pressure loss of the system is the loss in Section A, plus the loss in Section F (or B), plus the loss in the outlet as follows: 40 Loss in Section A = 0.13 in. X 1..0..0 = 0.05 Loss in Section F (of B) Outlet Loss = 0.03 = 0,12 Total Pressure Loss = 0.20 in. DUCT CONSTRUCTION DETAILS Straight sections of round duct are usually formed from sheets, rolled to the proper radius with a longitudinal grooved seam. Each section is swaged 1.5 in: from each end and assembled with the larger end of the adjoining section butting against the swage. The sections are held in place by rivets, sheet metal screws, or by soldering. Rectangular ducts are generally constructed by breaking the comers and grooving the longitudinal seam, although some fabricators still use the standing seam. Elbows and transformation sections are generally formed with Pittsburgh comer seams because this seam is easier to lock in place than the double seam, but complicated fittings such as double compounded elbows are usually constructed with double seam comers.- The construc tion of these various seams, as well as the types of girth connections, are shown in Fig. 15. The application of the various slips and connec tions is outlined in Table 8. The end slip may be used wherever S slips are recommended. Where drive slips are used, the end slip may be ap plied on the narrow side of the duct, and the drive slips on only the maxi mum side. Ducts 25 to 30 in. in size should be reinforced between the joints, but not necessarily at the joint. . Ducts 31 in. and up should be reinforced at the joint and between the joints; if drive slips are used the angles are usually rivited to the duct about 2 in. from the slips. It is good practice to cross-break or kink all flat surfaces to prevent vibration or buckling due to the air flow and accompanying variations in internal pressure. The construction of elbows and changes of shape cannot be definitely outlined, because of the varied conditions encountered in the field, but in general, long radius elbows and gradual changes in shape -tend to maintain uniform velocities accompanied by decreased turbulence, lower resistance and a minimum of noise. ; Heavy canvas connections (asbestos cloth if there is a fire hazard) are recommended on both the inlet and outlet to all fans. Self-vulcanizinK Air Duct Design 723 adhesive tapes are available for this purpose and for sealing joints in duct work. The fan discharge connections shown in Fig. 15 are marked good, fair, and poor in the order of the amount of turbulence produced.. An inspection of the heater connections shown in Fig. 15 will readily show that uniform velocity through the heater cannot be expected in the diagram Grooved seam Standing seam $ slip End slip -. Itojbte ettsbuitf) Rdrtrod . Pocket Good Far Heater, fitter, and washer csnnectians poo. Sma" Large Easement around - obstructions Diverter type CBnch collar (preferred) type Branch tekeoffs Fig. 15. Sheet Metal Duct and Arrangement Details 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 require an increase in the duct size m order to maintain as nearly uniform velocity as possible. Branch take offs should always be arranged to cut or slice 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 provided. For design of such 724 CHAPTER 32 1954. Guide dampers and other fire protective details, see Pamphlet No. 90, of the National Board of'Fire Underwriters.* 'The recommended gages for steel (or iron) and aluminum sheet metal rectangular ducts are given in Table 8. Steel or iron sheets are specified according to the'Manufacturers or U. S. Standard Gage System. Aim minum sheets are specified according to the American or Brown & Sharpe Gage System. Weights of black and galvanized steel and iron sheets per square foot of surface for various gages are given in Table 9, Similar data for 2S aluminum sheets will be found in Table 10. Weights of standard Table 8. Recommended Sheet Metal Gages fob Rectangular Duct Construction* Alu minum B.&S. Gaos Steel' U. S. Std. Gage Maximum Side, Inches Type op Transverse Joint Connections0 Bracing 24 26 Up to 12 S, Drive, Pocket or Bar Slips, on None 7 ft 10 in. centers 13 to 24 S, Drive, Pocket or Bar Slips, on None 7 ft 10 in. centers 22 24 25 to 30 S, Drive, 1 in. Pocket or 1 in. Bar lx lx} in. angles Slips, on 7 ft 10 in. centers0 4 ft from joint 31 to 40 Drive, 1 in. Pocket or 1 in. Bar 1 x 1 x } in. angles .... Slips, on 7 ft 10 in. centers* 4 ft from joint 20 22 41 to 60 1} in. Angle Connections, or 1} in. 1} x l} x } in. angles Pocket or 1} in. Bar Slips with 4 ft from joint If in. x in. bar reinforcing on 7 ft 10 in. centers* 18 20 , 61 to 90 1$ in. Angle Connections, or 1$ in. Pocket or If in. Bar Slips 1} x 1} x i in. diagonal angles, or 1} x 1} x } 3 ft 9 in. maximum centers with in. angles If x f in. bar reinforcing 2 ft from joint 16 18 91 aod up 2 in. Angle Connections or If in. Pocket or If in. Bar Slips 3 ft 1} x 1} X } in. diagonal angles, or 1} x 1} x 1 9 in. maximum centers with If x in. angles f in. bar reinforcing* 2 ft from joint " For normal pressures and velocities (see Table 4) utilized in typical ventilating and air conditioning sys tems. Where special rigidity or stiffness is required, ducts should be constructed of metal two gages heavier. All uninsulated ducts 18 in. and larger should be cross-broken. Cross-breaking may be omitted on uninsu lated ducts if two gages of heavier metal are used. k Other joint connections of equivalent mechanical strength and air tightness may be used. 6 Duct sections of 3 ft 9 in. may be used with bracing angles omitted, instead of 7 ft 10 in. lengths with joints indicated. . * Ducts 91 in. and larger require special field study for hanging and supporting methods. copper sheets are given in Table 11. In calculating the total weight of a given length of duct work from these tables, it is customary to add'20 percent for the weight of joints and bracings. Aluminum sheets of the 2S and 3S type alloy and % hard temper art readily workable, and can be used for practically all duct work. The 2S type (commercially pure aluminum) is suitable for all, except very largo ducts. For large ducts, where more strength is desired, the 3S alloy with % or hard temper is frequently used. The higher tempers, particularly full hard, do not'have the formability of the lower tempers. For very large ducts, where considerable strength is required, aluminum sheets Air Duct Design Table 9. Weights of Black and Galvanized Sheets 725 u.s. Std. Gags . slack Sheets Approximate Thickness, In. Weight Per Square Foot Galvanized Sheets* Approximate Thickness, In. Weight' Per Square Foot Steel Iron Ounces Pounds Steel Iron Ounces Pounds .30 0.0123 0.0125 8 1228 0.0153 0.0156 10 26 0.0184 0.0188 2024 0.0245 16 22 . 0.0313 20 0.0368 0.0375 24 18 0.0490 0.0500 32 16 0.0613 0.0625 40 14 0.0766 0.0781 - 50 12 0.1072 0.1094 70 11 0.1225 0.1250 80 10 0.1379 0.1406 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 - 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 0.0415 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 gaged before galvanizing and are therefore approximately 0.004 in. thicker. should be 2 gages heavier than indicated in Table 8, and should be amply stiffened. Joints can be of any of the standard designs, and can be fabri cated in the same manner as iron. JEtepeated sharp bending and rebending should be avoided, as aluminum has a tendency to crack under such treat ment. Aluminum of 16 B. & S. gage or heavier can readily be welded by the metallic arc or acetylene process. Soldering is difficult and is not gen erally recommended. Riveting is done in the same manner as in iron or steel sheet. Self-tapping screws tend to loosen because of the softness of aluminum. HEAT LOSSES FROM DUCTS In designing duct systems, the heat gains or losses of ducts should not be neglected. Heat gains in large duct systems can be quite considerable, not only if the duct passes 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 to the various supply outlets is necessary in order to compensate for the heating effect of the duct surface. The thermal transmittance U for ducts can be found as follows: For uninsulated metal duct, U = -- ^ ^ (20) ' 7i +7o 10.aable Weights and Thicknesses of 2S Aluminum (Density 0.098 lb/cu in.) B- * S. Gaos 28 26 24 22 20 18 16 14 Thickness, Inches Decimal Nearest. Fraction 0.012 0.016 0.020 0:025 0.032 0.040 0.051 0.064 1/64 1/64 1/64 1/32 1/32 3/64 3/64 1/16 . Weight per Square Foot Ounces Pounds 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 726 CHAPTER 32 For uninsulated non-metallic ducts, 1 1954 Guide (21) where U ~ overall coefficient of heat transfer, Btu per (hour) (square foot) (Fahren* . heit degree). . ft = surface conductance (inside) Btu per (hour) (square foot) (Fahrenheit degree). fo = surface conductance (outside) Btu per (hour) (square foot) (Fahrenheit degree). x -- thickness, inches. . Jc = unit conductivity of material, Btu per (hour) (square foot) (Fahrenheit degree per inch thickness). 11.Table Weights and Thicknesses of Standard Copper Sheets'1 Rolled to Weight Weight pee Square Foot Thickness. Inches Nearest Gage No. Ounces 10 12 14 16 18 20 24 28 32 36 40 44 48 56 64 Pounds 0.625 0.750 0.875 1.000 1.125 1JS50 1.500 1.750 2.000 2250 2.500 2.750 3.000 3.500 4.000 Decimal Equivalent 0.0135 : 0.0162 0.0189 0.0216 ' 0.0243 0.0270 0.0324 0.0378 0.0432 0.0436 0.0540 0.0594 0.0648 0.0756 0.0864 . Nearest Fraction A 'A 'A 'A 'A 'A 'A `A 'A 'A 'A 4* % B. & S. 27 26 25 22223210 19 17 16 15 15 14 1113 Stubs 29 27 26 24 23 22 21 20 19 18 17 17 16 15 14 U.S.STD. 29 . 28 26 25 24 23 22 20 19 18 17 17 16 14 13 Variations from these weights most be Expected in practice. 31 Where x is small and k is large, however, the factor 7 is of little impor tance and may be neglected. Film conductance / i for air flowing in ducts apparently depends only on the velocity of the air and the diameter of the duct. A fairly reliable inside coefficient can be calculated from Schultz's modified equation: f= J' (22) where v = velocity of air in duct, feet per second. D = inside diameter of duct, feet. Film conductance f0 depends on a number of variables including tem perature, diameter, and emissivity of the outer surface, and can be calcu lated from data in Chapter 5. From this explanation, it is seen that it is unwise to recommend a given value of U for all uninsulated metal ducts. Air Duct Design The heat loss from a given length of duct can be expressed by: 727 <2. - VPl (23 where . Qw = heat loss through duct walls, Btu per hour. P = perimeter of duct, feet. ; l = length of duct, feet. ti = temperature of air entering duct, Fahrenheit degrees. <4 = temperature of air leaving duct,. Fahrenheit degrees. 1% = temperature of air surrounding duct, Fahrenheit degrees. The heat given up by the air in the duct is: where Qw = 0.24u>(*, - tt) = 14.44V^ih ~ti) .! (24) to = weight of air through duct, pounds per hour. A = cross-sectiona.1 area of duct, square feet. Vn = mean velocity^of fluid, feet per minute. pv = density of air at specified temperature at which velocity Vm, is measured pounds per cubic foot. ' Equating (23) and (24): t\ -- 2U 28.84Vmpv t\ 4" 2 1 XJ PI Let y = ^ 1^or rec*'anSu^ar ducts, and for round ducts and solve for h and k h(y + 1) -- 2ti (.y - 1) (25) , tAy - 1) +21, (Tnr (26) For low velocities and long ducts of small more accurate formula may be used as follows: cross-section, a somewhat where 1* + u (27) ~ 14.4ApvF,,' e - Naperian base of logarithms = 2.718. in using Equations 25, 26, and 27, one of the duct air temperatures will 06 unknown and will be obtained by substitution of the other known or assumed values. Heat loss coefficients for insulated ducts with various conductivities ,r S'ven in Fig. 16. The conductivities of various materials, which are inT 0a mean temperatures, ranging from about 70 to 90 F, will be found table 2 of Chapter 9. For cases where the mean temperature is other CHAPTER 32 1954 Guide 728 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 negElxeacmtepdle. 7: Determine the ente:ring air temperature and heat loss for a duet 24 X 31'' in. cross-section and 70 ft in length, insulated with in. of a material having a Fig. 16. Heat Loss Coefficients fob Instjuated Ducts* ;V * For round ducts less than 30 in. diameter, increase heat transmission values by the percentages she*? below. -` Thickness op Insulation (Inches) 6$T 12 to 21 in. Duct Diameter.. a ;5% ' 2% 7% 3% 4% --21 to 30 in. Duct Diameter.. ---------- r~T3R-y-. conductivity of 0.35 Btu at 86 F mean temperature, carrying air at a velocity 9{&k,. fpm, measured at 70 F, to deliver air at 120 F with air surrounding the duct at. Solution: Referring to Fig. 16, the overall heat transmission coefficient is foun J;;; to be 0.49 Btu. From Table 1, Chapter 3 the density of air at 70 F and 29.921 m. "4 ; ~:V. Air-Duct Design 729 is found to be 1/13.348 = 0.0749 lb per cu ft. Substituting these and the other given values in Equation 25, and <i will be as follows: " 28.8 X 6 X 1200 X 0.0749 45.3 0.49 X 10 X 70 ' 120(45.3 + 1) - 80 45.3 - 1 Substituting in Equation 23: 123.7F . Q. = 0.49 X 10 x 70 7-+-12Q^ - 40j = 28,100 Btu per hr. For special considerations which apply to insulation of ducts in marine installations see Chapter 48. MAINTENANCE . Duets should be designed in such a manner as to enable easy mainte nance.23 .They should have enough access doors, not only to enable in spection, but also to_. facilitate cleaning of the ducts.24 The periodic clean ing of the ducts should be part of the regular maintenance schedule. It should be done.efficiently and competently to avoid difficulties or hazards in the operation of the system.26'25 LETTER SYMBOLS USED IN CHAPTER 32 a = coefficient of contraction. . e = absolute roughness, feet. P = density of air under actual (operating) conditions, any consistent units.. p = density of air under standard conditions, any consistent units. p = density at which Fn, is measured, pounds per cubic foot. A = cross-sectiou area of duct, square feet. A, = area of inlet duct, square feet. At = area of outlet duct, square feet. A'i= area of vena contracts, square feet. o = length of one side of rectangular duct, inches. (Other side is 5.) b = length of one side of rectangular duct, inches. (Other side is a.) . C and Ci = dynamic loss coefficients, dimensionless.. Ci = regain constant, dimensionless. D ~ inside diameter of duct, feet. <4 =, circular equivalent of a rectangular duct for equal frictic and capacity, inches. e = Naperian base of logarithms = 2.718. . / = non-dimensional friction coefficient. /i = surface conductance (inside) Btu per (hour) (square foot) (Fahren heit degree). . f,, = surface conductance (outside) Btu per (hour) (square foot) (Fah renheit degree). g = acceleration due to gravity, 32.17 feet per (second) (second). H = duct dimension perpendicular to plane of bend, feet. . H/W = aspect ratio, dimensionless. B, = pressure loss due to. sudden contraction, based on standard air, inches of water. H, = pressure loss due to sudden enlargement, based on standard air, inches of water. = pressure loss due to gradual enlargement, based on standard air, inches of water. H, = dynamic loss for standard air, inches of water, o i and ff = static pressure head at given points (1) and (2), inches of water. Hr = regain static pressure for standard air; inches of water. AH = total pressure loss, inches of water. ' 730 CHAPTER 32 1954 Guide h0 = friction loss under actual (operating) conditions, any consistent uuits- ' . n -L n - ho = pressure loss due to sudden contraction, feet of fluid flowing. ho -- 'pressure loss due to sudden enlargement, feet of fluid flowing. h, = friction loss, feet of fluid flowing. hr = regain in static pressure, feet of fluid flowing. h, = friction loss under standard conditions, any consistent units. ho = total dynamic pressure loss, feet of fluid flowing. k = conductivity, Btu per (hour) (sq ft) (Fahrenheit degree per inch). L = additional equivalent length of duct for loss in elbows, feet. L/W and L/D = additional equivalent length in terms of width and diameter, dimensionless. J = length of straight duct, feet. ` P = perimeter of duct, feet. Qo = air quantity, cubic feet per minute. Qw = heat logs through duet walls, Btu per hour. R -- centerline radius of elbow, or vane radius as noted, feet. R/W and R/D = radius ratio, dimensionless. r -- loss through specified duct sections, inches of water, fi =3 temperature of air entering duct, Fahrenheit degrees. 1, = temperature of air leaving duct, Fahrenheit degrees. (j = temperature of air surrounding duct, Fahrenheit degrees. . U - thermal transmittance coefficient, Btu per (hour) (square foot), . (Fahrenheit degree). _ V = mean velocity of standard air, feet per minute. Fm " mean velocity of air or fluid, feet per minute. _ - Yi = mean velocity of standard air in inlet duct section, feet per minute.-. n , Ft = mean velocity of standard air in outlet duct section, feet per minute,; v = mean fluid or air velocity, feet per second. VI == mean velocity in inlet duct section, feet per second. Vi = mean velocity in outlet duct section, feet per second. W -- duct dimension in plane of bend, feet. w = weight rate of air flow through duct, pounds per hour. x -- thickness, inches.' REFERENCES 1 A.S.H.V.E. Research Paper No. 1280--A New Friction Chart for Round Ducts, by D. K. Wright, Jr. (A.S.H.V.E. Transactions, Vol. 51, 1945, p. 303). ! Friction Factors for Pipe Flow, by L. F. Moody (A.S.M.E. Transactions, Vol. 66, 1944, p. 671). 3 See Chapter 1 for definition of standard air. \ 4 Friction Charts for Gases Including Correction for Temperature, Viscosity and Pipe Roughness, by R. D. Madison and W. R. Elliot (A.S.H.V.E. Journal Section, ;.V Heating, Piping and Air Conditioning, October, 1946). 3 Friction Equivalents for Round, Square and Rectangular Ducts,_ by R. G; Huebscher (A.S.H.V.E. Journal Section, Heating, Piping and Air Conditioning, Decem ber, 1947). . Winter Air Conditioning, by S. Konzo (National Warm Air Healing and Air Con ditioning Association, 1939, p. 363). ' .7 Modem Air Conditioning, Heating and Ventilating, by W. H. Carrier, R- E. Cherne and W. A. Grant, 1940, p. 234 (Pitman Publishing Corp.). 3 Heating, Ventilating and Air Conditioning, by L. A. Harding and A. C. Willard, 1932, p. 673 (John Wiley and Sons). I A.SE.V.E. Research Report No. 1405--Energy Losses in 90-Depee Duct ElbowB: A Survey and Analysis of Available Information, by D. W. Locklin (A.S.H.V.E. Transactions, Vol. 56,1950, p. 479). 10 Pressure Loss in Ducts with Compound Elbows, by J. R. Weske {NationalA - visory Committee-for Aeronautics, Advance Restricted Report W-39, February 1943). II Pressure Losses in Rectangular Elbows, by R. D. Madison and J. R- barker (Heating, Piping and Air Conditioning, July, p. 365, August, p. 427, Septembe , p. 483, 1936). 13 Fittings Losses for Extended-Plenum Forced Air Systems, by H. H. Korst, A. Buckley, S. Konzo, and R. W. Roose (A.S.H.V.E. Journal Section, Heating, Pip ing and Air Conditioning, February 1950, pp. 111-118. Air Duct Design 731 18 A.S.H.V.E. Research Report No. 216--Effect or Vanes in Reducing Loss in Elbows in Seven-Inch Square Ventilating Duct, by M. C. Stuart, C. F. Warner, and W. C. Roberts (A.S.H.V.E. Transactions, Vol. 48, 1942, pp. 409-424). 14 Pressure Losses Due to Bends and Area Changes in Mine Airways, by G. E. McElroy (U. S. Bureau of Mines, Information Circular I.C. 6663, p. 4). 16 Pressure Losses Resulting from Changes in Cross-Sectional Area in Air Ducts, by A. P. Kratz and J. R. Fellows (University of Illinois Engineering Experiment Station, Bulletin No. 300). .. 16 Fan Engineering, (R. D. Madison, Editor) 5th ed., 1948, pp. 124-128 (Buffalo Forge Company). ...... . 17 Design of Power Plant Installations: Pressure-Loss Characteristics of Duct Components, by J. R. Henry (National Advisory Committee for Aeronautics, Advance Restricted Report L4F26, June 1944, L-208). 18 Air Conditioning Principles, by C. O. Mackey, 1941, p. 158 (International Text book Company). * ,y . 19 Fluid Mechanics, by R. C. Binder, 1943, p. 152 (Prentice-Hall). * Modern Diffuser Design, by G. N. Patterson (Aircraft Engineering, Sept., 1938 p. 267) and The Design of Airplane Ducts, by G. N. Patterson (Aircraft Engineering, July, 1939, p.263). ' .. 21 Duct Sizing with Partial Static Regain, by R. H. Anderegg and F. W. Hutchin son (Heating, Piping and Air Conditioning, August, 1946, p. 97). 22 Power Sayings Through Static Pressure Regain in Air Ducts, by J. R. Fellows (Heating, Piping and Air Conditioning, April, 1939, p. 219). 23 Standards of the National Board of Fire Underwriters (N.B.F.U. Pamphlet No. 90, p. 21). . .y 24 Design of Air Conditioning Systems for Low Maintenance, by M..G. Kershaw (Refrigerating Engineering, October, 1946, p. 315). 26 Clean Your Ducts, by G. L. Candler (Heating, Piping and Air Conditioning, July, 1947, p. 83). . 2# Duct Leakage and Job Revision, by E. L. Schulz (Heating and Ventilating, October, 1944,.p. 83). . . BIBLIOGRAPHY FLUID FLOW (See Chapter 4) Engineering Applications of Fluid Mechanics, by J. C. Hunsaker and B. G. Right- mire, 1947 (McGraw-Hill Book Company, Inc.). : Elementary Mechanics of Fluids, by Hunter Rouse, 1946. (John Wiley & Sons Inc.). .' i'Tnv of Liquids, by W. H. McAdams .(Refrigerating Engineering, February, The Flow of Fluids in Closed Conduits, by R. J. S. Pigott (Mechanical Engineering, vol. 55, 1933, p. 497). ' . A Study of the Data on the Flow of Fluids in Pipes, by E. Kemler (A.S.M.E. transactions, Vol. 55, 1933, Hydraulics, p. 7). Mechanical Similitude and Turbulence, by T. von Karman (translated and re printed as Technical Memorandum N.A.C.A. No. 611, 1931). Turbulent Flow in Pipes, with Particular Reference to the Transition Region between the Smooth and Rough Pipe Laws, by C. F. Colebrook (Journal, Institute ! Cml Engineers, Vol. II, 1938-39, p. 133). Evaluation of Boundary Roughness, by H. Rouse (Proceedings Second Hydraulics Conference, University of Iowa, Bulletin 27, 1943). FLOW OF AIR IN DUCTS I Tr^^ona.^ Resistance to the Flow of Air in Straight Ducts, by F. C. Houghten, ik ik^?*lm7e*er> J- A. Zalovcik, and N. Ivanovic (A.S.H.V.E. Transactions, Vol. 1939, p. 35). Arndts of Factors Affecting Duct Friction, by J. B. Schmieler, F. C. Houghten, d H. T. Olson (A.S.H.V.E. Transactions, Vol. 46, 1940, p. 193). 732 CHAPTER 32 1954 Guide The Flow of Air In Ducts, by E. Kemler (Healing and Ventilating, May 1936, P- 38). i fTinin! Sts.tic usd Velocity Pressure by A. A. Bsrsstusff {HscitiTiQ} QTid Air Conditioning, March 1932, p. 195). PRESSURE LOSS IN ELBOWS Experimental Investigation of Velocity Distributions Downstream of Single Duct Bends, by John R. WeBXe (JVotional Advisory Committee for Aeronautics Technical NoItenv1e4s71ti,gJaatinounasroy,f 1th9e48F).low in Curved Ducts at Large Reynolds Numbers, by John R. Weske (Journal of Applied Mechanics, December, 1948, pp. 344-348. Flow of Fluids in Curved Passages, by J. Eusticc (Engineering, Vol. 120, 1925, p. 6N0e4w). D.ata for the Design of Elbows in Duct Systems, by Loring Wirt (General Electric Review, Vol. 30, June 1927, pp. 286-296). ASHVE Research Repoet No. 1216--Effect of Vanes in Reducing Pressure Loss in Elbows in Seven-Inch Square Ventilating Duct, by M. C. Stuart, C. F. Warner, and W. C. Roberts (ASHVE Transactions, Vol. 48,1942, pp. 409-424). Pressure Loss in Elbows and Duct Branches, by Andrew Vazsonyi (ASME Trans actAioSnsH,VAEprRile1s9e4a4r, cphp.R1e7p7o-1r8t3)N. o. 1329--Friction Equivalents for Round, Square and Rectangular Ducts, by R. G. Huebscher (ASHVE Transactions, Vol. 54,1948, p. 101). .' Loss in 90-Degree Pipe Bends of Constant Circular Cross Section, by Albert Hofmann (Transactions of the Hydraulic Institute of the Munich Technical University BuPlleretsinsu3r,e1L9o2s9s,eAs SinMREec1t9a3n5g, uplapr. E2l9b-o4w1)s. , by R. D. Madison a. nd J. R. Parker (ASME Transactions, AER 58-2, April 1936, pp. 167-176). ASHVE Research Report No. 1211--Pressure Loss Caused by Elbows in Eight- Inch Round Ventilating Duet, by M. C. Stuart, C. FI Warner and W. C. Roberts (ASHVE Transactions, Vol. 48,1942, pp. 335-350). * Friction of Air in Elbows, by A. I. Brown (Power Plant Engineering, August 15, 193L2o,sps. o6f30P).ressure Due to Elbows in the Transmission of Air Through Pipes or Duets, by Frank L. Busey (ASHVE Transactions, Vol. 19, 1913, pp. 366-376). The Resistance to Flow of Air at Bends and in Straight Airways, by W. E. Cooke and I. C. F. Statham (Institution of Mining Engineers Transactions, Vol. 76-77,. JunAen11In, v1e92s9ti,gpapti.o1n88o-f21P2r)e. ssure Losses in Air Duct Elbows, by Oliver E. Parker (Northeastern University thesis, May 28, 1934). * Investigation of Air Flow in Right Angle Elbows in a Rectangular Duct, by Charles H. McLellan and Walter A. Bartlett, Jr. (National Advisory Committee for Aeronautics, Advanced Restricted Report L-328, October, 1941). . DUACRTaDtioEnSaIlGMNethod of Duct Design, by L. G. Miller (ASHVE Transactions, Vol. 43,1937, p. 71). MISPeCrEfoLrmLAanNcEeOTUesSts of Asbestos Insulating Air Ducts, by R. H. Heilman and R. A; McArthur (A.S.H.V.E. Transactions, Vol. 44, 1938, p. 197). Aluminum in Healing, Ventilating and Air Conditioning, Reynolds Metals Co., Louisville, Ky. ' 1 CHAPTER 33 FANS Types, Fan Performance, Fan Laws, Fan Performance Curves, System Characteristics, Fan Arrangements, Fan Control, Motive Power, Fan Selection, Fan Installation, Fan Applications IN HEATING, ventilating and air conditioning practice, the devices used to produce air flow are variously known as Ians, blowers, exhausters or propellers. The A.S.M.E. Test Code1 limits fans to those in which the fluid density change does not exceed 7 percent (one psi at atmospheric pressure) and labels as compressors those devices operating beyond that pressure range. Since air conditioning rarely requires pressures of over \ psi, all such devices will be known as fans and the air will be considered non-compressible. 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 curva ture 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 in clination, 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 im peller diameter; materials and methods of fabrication, depending upon de sign and preference of manufacturer. Tubeaxial and vaneaxial fans, usu ally used against appreciable resistance, commonly have relatively large hubs and helical blades (the angle varies radially along the blade). The blades may be of uniform 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 impeller and enclosure is common practice. Vaneaxial fans incorporate guide vanes to modify per formance 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 merely mounted within a plate or ring. The fan nomenclature in Fig. 1 has been standardized by the National Association of Fan Manufacturers} FAN PERFORMANCE Fan performance is a statement of volume, total pressures, static pres sures. speed, power input, mechanical and static efficiency, at a stated .r?nsity. These terms are defined by the National Association of Fan onufaciurers2 as follows: . !' Volume handled by a fan is the number of cubic feet of air per minute expressed Ian outlet conditions. 733 -f? 734 CHAPTER 33 1954 Guide M. 2. Total pressure of a fan is the rise of pressure from fan inlet to fan outlet. i? 3. Velocity pressure of a fan is the pressure corresponding to the average velocity - det4e.rmSiianlaictiopnrefsrsoumrethoef vaoflaunmeisotfhaeirtfolotawl aptrethsseufraendoimutilneist haereda.by the fan velocity ~ pressure- ; 5. Power output of a fan is expressed in horsepower and is based on fan volume and the6.faPnotwoetralinppreuststuorea. fan is expressed in horsepower and is measured horsepower . del7iv. eMreedchtoantihceal feafnficsiehnacfyt.of a fan,is the ratio of 'power output 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. Pan outlet area is the inside area of the fan outlet. 10. Pan inlet area is the inside area of the inlet collar. . While the total pressure truly represents the actual pressure developed by the fan, the static pressure may best represent the useful pressure for overcoming resistance. In many installations, since the outlet. velocity f of the fan is greater than the duct velocity, some of the velocity, pressure -l may be utilized by conversion to static pressure within the system. How- ever, due to the uncertainty of the flow at the points of velocity change, the ' amount of conversion is seldom known and therefore, most fan tables list v only the static pressure as available to overcome the system resistance. ';;'^ . - ' Fig. 1. Names and Definitions of Types of Fans ;i I Propeller Fan A propeller fan consists of a propeller or disc wheel within?, a mounting ring or plate. . ,. ` ' v ' ' . -' ' ' iv ,'l8..' Tubeaxial Fan - , A tubeaxial fan consists of an axial flow wheel within'*.1: cylinder. ... i,v;1.: .-iu'J\ '- Vaneaxial Fan , A vaneaxial fan consists of an axial flow wheel within a cyl inder, combined with a set of air guide vanes located either before or after the wheel. ; Centrifugal Fan A centrifugal fan consistB of a fan rotor or wheel within-6 scroll type of housing. Fans 735 According to the Standard Test Code3 the efficiencies may be determined by the formulas: :.. . .. Mechanical (total) Efficiency = 0.0001573 X (cfm) X total pressure (inches water) horsepower input 0.0(X)1573 X (cfm) X static pressure (inches water) Static Efficiency = horsepower input As the static pressure is often more useful than total pressure, static efficiency is likewise many times more useful than mechanical efficiency. However, where a high outlet velocity can be effectively utilized, the static efficiency fails to be a satisfactory measurement 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 becoming increas ingly important. Unfortunately, no method has yet been devised for accurately measuring -the sound actually discharged into a duct system. The A.S.H.V.E. Research Laboratory, in cooperation with the U. S. Navy, has a program underway seeking to find a method. Many manufacturers list the average sound (for various fan operating conditions) measured at seven stations near the fan. These stations, as specified in the N.A.F.M. 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 relative sound generated by various types and sizes of fans under comparable operating conditions. FAN LAWS6 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, groups 1 to'6, Q = air volume and P = static, velocity or 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 () Q; () P: (c) Power: Varies as fan speed. Varie9 as square of fan speed, Varies as cube of fan speed. Variation in Fan Size: Constant Tip Speed--Constant Air Density Constant Fan Proportions--Fixed Point of Rating (a) Q: Varies as square of wheel diameter. (b) P: Remains constant. (c) RPM: Varies inversely as wheel diameter. (d) Power: Varies as square of wheel diameter. 736 CHAPTER 33 1954 Guide 3. Variation in Fan Size: At Constant ftPAf--Constant Air Density Constant Fan Proportions--Fixed Point of Rating (o) Q: Varies as cube of wheel diameter. (6) 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. (b) P: Varies as density. (c) Power: Varies as density. A 5. Variation in Air Density: Constant Pressure--Constant System Fixed Fan Size--Variable Fan Speed (a) Q: Varies inversely as square root of density. (i>) 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 of Air--Constant System Fixed Fan Size--Variable Fan Speed (o) Q: Varies inversely as density. (i>) P: Varies inversely as density. (c) RPM: Varies inversely as density. (d) Power: Varies inversely as square of density. I '% i-# r t r,^v.-: .I Examples 1 to 4 illustrate the application of the preceding fan laws. Example t: A certain fan delivers 12,000cfm 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? /-.-. 15.000 Speed = 400 X = 500 rpm 12.000 Ml# Static pressure = 1 X 1.56 in. Power = 4 = 7.81 hp if Example 8: A certain fan delivers 12,000 cfm at 70 F and normal barometric pres* ' sure (density 0.075 lb per cubic foot) at a static pressure of 1 in. of water when operat-. y ing at 400 rpm, and requires 4 hp. If the air temperature is increased to 200 F (den-. / sity 0.0602 lb) and the speed of the fan remains the same, what will be the static .; pressure and power? '; 0,0602 Static pressure = 1 X = 0.80 in. 0.075 Power = 4X --- = 3.20 hp 0.075 . i Example 3: If the speed of the fan of Example 8 is increased so as to produce a static pressure of 1 in. of water at the 200 F temperature, what will be the spec capacity, and power? ... Fans / 0.075 Speed = 400 X = 446 rpm , y 0.0602 . /0.O75 Capacity . = 12,000 X V 0.0602 .=' 13.392 cfm (measured at 200 F) Power = 4 X /om = 446 y 0.0602 737 Example 4.' If the speed of the fan of the previous examples 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 Speed = 400 X--= 498 rpm 0.075 Capacity = 12,000 X = 14,945 cfm (measured at 200 F) .: U.UfaOz ... .. ,,. : - 0.075 ' Static pressure = 1 X-------- = 1.25 in. , 0.0602 -- - :. ................ P,, omr = 4x(/0o.07*5 JV =Whp.: ;- ; . . . 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 5: Assuming that a fan with a 36 in. diameter blast wheel will deliver f">p00 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 X 12,000 = 23,400 cfm Static pressure = X X 1 = 1.56 in. Horsepower = 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 and static efficiency, to actual'volume, for the desned range of volumes. Figs. 2, 3. and 4 illustrate performance (some times called characteristic) curves of various types of fans. Centrifugal fans6 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 in- 738 CHAPTER 33 1954 Guide clined backward away from direction of rotation. They are also character . ized as slow speed, moderate speed and high speed types, respectively, al though 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 and 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 en trance. Straight radial blades are most frequently found in pressure fans and material 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 imparted to the air by virtue of its velocity Fans 739 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 is being generated by conversion of velocity, which is small at low capacity. The maximum efficiency occurs at approximately 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 efficiency, 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 constantly rising from free delivery Fig. 2. Percentage Performance Curves of a Forward-Curved Blade Centrifugal Fan leaving the impeller. 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 back ward, oppositional. Thus a fan with forward-curved blades depends less on centrifugal force for its pressure, and more on velocity pressure conver sion in the scroll, with the result that it may run at relatively low speed. Conversely, a fan having backward-curved blades builds up more of its pres sure by centrifugal force (a more efficient form of energy transfer) and less by velocity conversion and, therefore, must run at a higher speed. Like wise, a fan having forward-curved blades will produce the greatest ca pacity of any type of the same size when operating against no resistance. Since the energy imparted to the air depends on the velocities,7 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 backwardcurved blades, the energy per pound of air may decrease, and in a fan Fig. 3. Percentage Performance Curves of a Backward-Curved Blade Centrifugal Fan nearly to point of no delivery. The horsepower reflects the energy-velocity relationship 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 approxi mately with the maximum efficiency. The sound is again a minimum near maximum efficiency, 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 whh fixed inlet vanes. Such vanes applied to a partially backward-curved mpeller give the steep, constantly rising pressure characteristic, and the self-limiting horsepower feature of the full-backward-curve. They also CHAPTER 33 1954 GuideIt! stabilize the flow entering the impeller when adverse flow conditions existi<|| in the approach to the inlet. / flow fans develop .none of their static pressure by centrifugal loree, but all from the change in velocity in passing through the impeller, and itst|^ conversion into static pressure. They are'thus inherently high velocity fans, and are very dependent on blade conformation for good characteristicsJaw For that reason, an air foil section, such as developed in wind tunnels forlgy aircraft work8 is frequently used. Since any shape of blade can only be'Sj correct for a narrow range of capacity at constant speed, the performance//; curves for any blade show definite characteristics. To absorb energy, the'Jgt air must be given a tangential motion in passing the impeller,7 and when'pj operating against higher pressures, must have guide vanes (see vaneaxial -| fans) to obtain best efficiencies. . Fans 741 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 comparable to centrifugal fans, is again lowest near maximum efficiency, but has a charac teristic rise when the fan is operating at low capacities and the stall point of the blade section is reached. Since propeller Jans 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" I I 1 .1 Fig. 4. Percentage Performance Curves of an Axial Flow Fan . '. . ;,f While axial flow fans are inherently a higher capacity type than centrif" ugal fans, they, too, may be designed with widely varying characteristics?; As with a centrifugal fan, the pressure 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 condition 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 centrifc ugal fan with backward-curved blades. Fig. 4-shows the performance curves for a typical design. : . . ;uj*r. The horsepower curve may be flat with a self-limiting characteristic: as in a backward-curved blade centrifugal fan, or it may have a generally1 AIR VOLUME. CUBIC FEET PER MINUTE IN THOUSANDS Fig. 5. Parabolic System Characteristic Curves horsepower is highest at no delivery, and decreases toward free delivery, m 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 duct work, heaters, air washers, "iters, 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 oliow the simple parabolic law in which the static pressure or resistance o flow of air varies as the square of the volume flowing through the sys tem. Heating and ventilating systems follow this law very closely and no serious error is introduced by its use. When a constant speed fan curve tor a given size fan is super-imposed 742 CHAPTER 33 1954 Guide'. ?' V*V-7' ~ Fans 743 No2-5W,SI No 3 - SW, SI No3-OW,Dl No 4 - SW. SI Counter-Clockwise Top Horizontal Clockwise Top Horizonte - Clockwise ' Bottom Horizontal Counter-Clockwise Bottom Horizontal Clockwise Up Blast Counter-Clockwise Up Blast Counter-Clockwise Down Blast Clockwise Down Blast No 7 - SW, SI No 7 -DW, D1 - . No 8- SW, SI No 9" SW, SJ Fig. 6. Arrangement op Fan Drives Arr: 1, SW, SI. For belt drive or direct connection.Wheel overhung. Two bearings on base. ' Arr. 2, SW, SI. For belt drive or direct connection. Wheel overhung.. Bearings in bracket sup- - ported by fan housing. ' '. Arr. 3, SW, SI. For belt drive or direct connection. One bearing on each side and supported by fan housing. Not recommended in sizes 27 m. diameter wheel and smaller. Arr. 3, DW, DI. For belt drive or direct connection.- One bearing on each side and supported by fan housing. . ', Arr. 4, SW, SI. For direct drive. Wheel overhung on prime'mover shaft. No bearings on fan. Base or equivalent for prime mover. '. - ' .* Arr. 7, SW, SI. For belt drive or direct connection. Arrangement No. 3 plus base for prime mover. .' Not recommended in sizes 27 in. diameter and smaller. Arr. 7, DW, DI; For belt drive or direct connection. Arrangement No. 3 plus base for prime mover. Arr. 8, SW, SI. For belt drive or direct connection. Arrangement No.-l plus base for prime mover Arr. 9, SW, SI. For belt drive. Arrangement No. 1 designed for mounting prime mover on side of 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 intersection of the system characteristic curve and the fan character istic curve, and it is at this point that the combination will operate. In Fig. 5, system characteristic curves A, B and C cross the fan character istic curve at points X, Y and Z. The fan whose curve is shown, when applied to systems haying 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 which 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 represented by system characteristic curve B in Fig. 5. If a 100 per cent error had been made and the resistance were 2.5 in. instead of 1-2" 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 decreased from a design volume of 13,000 cfm to 10,000 cfm. If the resistance to flow had been over-estimated and the resistance Counter-Clockwise Top Angular Dowd- . _ Clockwise Top 'AnguJar Down Clockwise Bottom Angular Uj> Counter-Clockwise Bottom Angular Up Counter-Clockwise top Angular Up Clockwise Top Angular Up Clockwise Bottom Angular Down Counter-Clockwise Bottom Angular Down *Fig. 7. Designation op Direction of Rotation and Discharge Note: Direction of Rotation is determined from the drive side for either single or double width or single or double inlet fans. (The driving side of a single inlet fan is considered to be the side opposite the inlet regardless of the actual location of the drive.) For fan inverted for ceiling suspension, direction of rotation and discharge b determined when fan b resting on floor. actually were 0.625 in., the system characteristic curve would be as shown in curve C, and the fan would deliver 16,400 cfm to the system instead of the design volume of 13,000 cfm. . In this example, extreme errors have been selected to emphasize the effect the square function of the system characteristic 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 system es timated 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 ?uch cases, the limiting systems may be plotted and the effect on fan per- ormance examined. For instance, a system might have a characteristic J-urve between A, shown in Fig. 5, as one limit, and B as the other limit. 1 he fan performance will then fall between points X and Y on the fan curve at a point determined by the system characteristics at that particular 744 CHAPTER 33 1954 Guide 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. FAN ARRANGEMENTS . Centrifugal fan arrangements have been standardized by the National Association of Fan Manufacturers. Figs. 6, 7 and 8 show the accepted designation as to arrangement of drive, rotation, discharge and motor position, for belt drive. Axial flow fans are either belt driven or direct connected, in accordance with, individual manufacturer's arrangements. Usually a choice of anti-friction`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, and this may be accomplished by a Location of motor is determined by facing the drive side of fan or blower and designating the motor po sition by letters W, X, Y or Z as the case may be. Fig. 8. Motor Position, Belt or Chain Drive 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 speea of the fan and 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 fan inlet vanes 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 consideration 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, lowering the 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 Fans 745 are sometimes made with adjustable blades to permit balancing the fan against the system, or making seasonal adjustment. , MOTIVE POWER Heating, ventilating and air conditioning fans are usually driven by. electric motors, although other prime movers may be used. The small sizes of fans, and especially those operating 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 se lect at least the standard size next larger than the fan requirements. Di rect-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 by-pass dampers, thus greatly reducing the system resistance. If such a system 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 backward-curved blades, the volume peak would not make it necessary to provide addi tional motor power. In selecting fans for such a system, sound ratings should be given careful consideration. Where a system is constant, and has no 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 properly selected. Fig, 5 shows that the system re sistance varies as the square of the volume, and the fan static pressure varies approximately inversely as the volume, thus greatly offsetting the'trend toward both increase 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 io for characteristics of various types of motors, . FAN SELECTION The following information is required to select the proper type and size of fan: 1. Capacity in cubic feet per minute2. Static pressure or system resistance. 3. Air density if other than standard. 4. Type of application or service. o- 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 manu facturers supply fan tables or curves which usually show the following factors for each size of fan operating against a wide range of static pres- *ures: (]) volume of air in cubic feet per minute (68 F, 50 percent rela tive 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 bold-face or italicized figures in the capacity tables. 746 CHAPTER 33 1954 Guide Often the service determines the type of fan. When operaticm occurs with little or no resistance, and particularly without a duct system, the propeller fan is indicated for convenience and low cost. When resistance is low the power required is low, and efficiency becomes a secondary im portance. When a duct system is involved the choice is usually made between a centrifugal fan and a tubeaxial or vaneaxial. At times the capacity-pressure-speed relationship (specific speed)9 dictates a choice. Usually, space, efficiency, sound, cost and serviceability must all be con sidered.10 In general, centrifugal and axial fans are comparable in effi ciency and sound, but the latter are lighter and require considerably less space, especially if arranged for straight-through operation. The compari son 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 expensive, and frequently requires more space. While requiring less space than the centrifugal, the Table 1. Good Operating Velocities and Tip Speeds for Ventilating Fans Static Inches op Water i i i I I 7 1 H H li 2 2i 2i 3 Forward Curved Blade Fans Backward Tipped and Double Tubeaxial and Curved Blade Fans Vaneaxial Fans Outlet Velocity. Tip Speed Feet per Minute Feet per Minute Outlet Velocity Feet per Minute Top Speed Feet per Minute Wheel Velocity Feet per Minute 1000-1100 1000-1100 1000-1200 1200-1400 1300-1500 1400-1700 1500-1800 1600-1900 1800-2100 1900-2200 2000-2400 2200-2600 2300-2600 2500-2800 1520-1700 1760-1900 1970-2150 2225-2450 2480-2700 2660-2910 2820-3120 3162-3450 3480-3810 3760-4205 4000-4500 4250-4740 4475-4970 4900-5365 800-1100 800-1150 900-1300 1000-1500 1100-1650 1200-1750 1200-1900 1300-2100 1400-2300 1500-2500 1600-2700 1700-2800 1800-2950 2000-3200 2600-3100 3000-3500 3400-4000 3800-4500 4200-5000 4500-5300 4800-5750 5300-6350 5750-6950 6200-7550 6650-8050 7050-8550 7450-9000 8200-9850 1100-1500 1250-1700 1400-1900 1500-2100 1650-2350 1800-2500 1900-2700 2150-3000 2350-3300 2500-3550 2700-3800 Wheel velocity is the axial mean air velocity through the inside diameter of the housing cylinder at the point of wheel location. axial flow fan is inherently less accessible for service. When high-tempera ture 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 permits less variation in air delivery when the resistance varies. Likewise, a flat sound curve mini mizes the change of moving into a region of increased noise. A fan having a high efficiency 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 class2 of construc tion, 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 Fans 747 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. Generally, 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 so, when noise is a con sideration, selection approaching maximum efficiency is indicated. Too large a fan may not only mean an unnecessary investment and an increased power consumption and sound, but1 may also give faulty performance if 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 systems, the characteristics of the fans available for use therewith 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 various devices whose individual resistances determine the static pressure, dictate the fan selec tion. Often a minor modification of the system may permit use of a ' smaller motor, and even a lower class2 of fan, with considerable saving of cost. Invariably, the sound generated is affected, as fans operating at high pressure produce more noise than at lower pressure (see Chapter 41). 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. AH ducts should be connected to fan outlets and inlets by means of un painted 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 unsigned to prevent transmission of vibrations through floors to the buildmg 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 41. FAN APPLICATIONS Many fan applications and the corresponding types of fan commonly u^ed are listed in the following paragraphs. Reference is also made to the chapters. where the applications are discussed. Central System Supply Fans (Chapter 30) are usually of the centrifugal 748 CHAPTER 33 1954 Guide type, since this application requires a wide range of satisfactory and quiet operation against relatively high pressures. They can readily be connected to apparatus of large cross-section on the inlet side, and to relatively small ducts on the outlet side. Comparative sizes have been standardized among manufacturers,2 and most rating tables cover a range of 700 to 500,000 cfm, and static pressures from i to 15 in. of water. Central system exhaust fans are predominately centrifugal, but the space conservation of the axial is being increasingly utilized. Tubeaxial and vaneaxial fan sizes are not yet standardized, but several manufacturers list capacities from 2000 to 100,000 cfm, and static pressures up to 3 in. of water. . . Exhaust fans are found in all types. Wall fans are predominantly 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 in corporated in factory-built pent houses or toof caps, or are provided with matching automatic louvers. Hood exhaust fans (Chapter 46) involving ductwork, are predominantly centrifugal, especially if handling hot, cor rosive 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. Spray booth exhaust fans (Chapter 46) are frequently centrifugal, especially if built into self-contained booths. Tubeaxial fans lend themselves particu larly well to this application where ease of cleaning and of suspension in a section of ductwork are advantageous. For such application built-in clean out doors are desirable. Material handling fans (Chapter 46) are always straight radial (or modified) blade centrifugal type. They are of heavier. construction, and have fewer blades and greater clearances than ventilating fans. Many characteristics are compromised to provide wear resistance and ease of maintenance. They are commonly listed in capacities' from 600 to 60,000 cfm, and static pressures up to 15 in. water. Mine fan applications11 vary greatly and require fans ranging from small 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 location, 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 of both centrifugal and vaneaxial types. The latter are particularly well adapted to both combatant and non combatant ships, where, compactness and fight weight are invaluable. Unitary systems, i.e., unit heaters, 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 relatively small suspended type where no ductwork is involved. Fans for units having considerable internal or possible external resistance, are mostly of the forward-curved blade, or so-called mixed flow centrifugal type. The latter is really a centrifugal type with axial inlets, having a pressure curve resembling a backward-curved blade centrifugal fan. Both ' of these types have the high capacities (in relation to displacement) reqUlr site for a compact unit. Ratings are frequently given for these units as separate fans, as well as in conjunction with the various internal resistances. Fans 749 In multiple units on a common shaft they, are fisted up to 40,000 cfm capacities. : Cooling tower fans (Chapter 35) are predominantly of the propeller type, but axial types are also used for packed towers, and occasionally a centrif ugal fan is used to supply forced draft. Circulating fans are invariably of propeller or disk type, and are made in a vast variety of blade shapes and arrangements. They are designed for pleasing appearance, as well as utility. General purpose fans are centrifugal fans of conventional design, built for service in the lower capacity ranges. They are built with the fan wheel mounted on the motor shaft, or connected to a self-contained belt driven arrangement. They are fisted in capacities from 100 to 20,000 cfm, and static pressures up to 1J in. water. .. . Kitchen fans for domestic use are small propeller fans, arranged for win dow or wall mounting, and with various useful fixtures. Their capacities range from 300 to 800 cfm. , Attic fans are used during the warm seasons to draw large volumes of outside air through a house or other building whenever the inside tempera ture exceeds the outside, and thereby utilize the cooling effect of the rela tively cool evening or night air. Research by the A.S.H.V.E.12 indicates that a two to three-minute air change is desirable in the North; 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 space, or in a hallway, and arranged to draw proportionately 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 escapes through windows or grilles; or the air may be drawn through grilles into the attic with the fan discharging directly 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 Fans are used to handle many gases other than air at normal tempera ture. 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 more practicable to plan on replacing a unit of standard material at more fre quent intervals. Explosive combinations usually dictate a non-sparking fan in which either all of the fan, or only those parts which might strike to gether if mal-adjusted, are built of non-sparking materials. Noxious, toxic, radio-active or pure or valuable gases call for special construction to Prevent leakage. This usually consists of a welded gas-tight housing, UanE flanged inlet and outlet, and some form of shaft seal. In most of these special applications, since it is desirable to keep all bear- 750 CHAPTER 33 1954 Guide mgs, drives and motors outside the gas stream, centrifugal fans are usually used and in arrangements 1, 2, 4, or 8 (Fig. 6). The exception'is in the case of fans handling explosive mixtures, where propeller or axial fans are per missible when built with explosion-proof motors and non-ferrous wheels. Fans handling hot air or gas are generally of the centrifugal types and follow arrangements 1 or 8 so that bearings, drives and motors are remote from the heat. If of double inlet type, they have inlet boxes and long shafts to keep the bearings outside the stream. Propeller or axial types are rare when the temperature exceeds 150 F. With temperatures above 600 F special heat resistant materials may be required for the rotors. In addition to a remote location for the bearings, external cooling is fre quently required when the temperature exceeds 200 to 250 F. This is often obtained by use. of air cooled or water cooled jackets. With anti friction bearings a heat radiating disk or a small circulating impeller between the fan and the nearest bearing is sometimes sufficient. Oil lu brication rather than grease lubrication is commonly recommended. REFERENCES 1 A.S.M.E. Test Code for Fans (American Society of Mechanical 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, pp. 2-5). Standard Test Code for Centrifugal and Axial Fans (A.S.H.V.E. and the Na tional Association of Fan Manufacturers, NAFM Bulletin No. 110, 1952, p. 18). ` Sound Measurement Test Code for Centrifugal and Axial Fans (National Asso ciation of Fan Manufacturers, Bulletin No. 110, 1952, p. 33). Noise Ratings of Ventilating Fans, by W. H. Hoppmann II and Fred Lager (A.S.H.V.E. Transac tions, Vol. 51, 1945, p. 271). . 5 Fan Laws Simplify Performance Calculations, by R. D. Moyer (Power, August 1946). 'The Centrifugal Fan, by Frank L. Busey (A.S.H.V.E. Transactions, Vol. 21, 1915, p. 43). 7 Energy Transfer Between a Fluid and a Rotor for Pump and Turbine Machinery, by Sanford A. Moss, Chester W. Smith and William R. Foote (American Society of Mechanical Engineers Transactions, 1941)". 8 The Characteristics of 78 Related Airfoil Sections from Tests in the Variable Density Wind Tunnel, by Eastman N. Jacobs, Kenneth E. Ward and Robert M. Pinkerton (National Advisory Committee for Aviation Report No. 460). Aerodynamic Characteristics of a Large Number of Airfoils Tested in the Variable Density Wind Tunnel, by Robert M. Pinkerton and Harry Greenberg (National Advisory Committee for Aeronautics Report No. 678). 8 The Specific Characteristics of Fans, by M. C. Stuart and J. B. Lusk (A.S.H.V.E. Transactions, Vol. 43, 1937, p. 57). . 10 The Axial Flow Fan and Its Place in Ventilation, by W. R. Heath and A. E. Criqui (A.S.H.V.E. Transactions, Vol. 50,1944). 11 Mine Ventilation, by J. J. Walsh (A.S.H.V.E. Transactions, Vol. 23, 1917, p. 659). Mine Ventilation and Its Relation to Health and Safety, by D. Harrington (A.S.H.V.E. Transactions, Vol. 51, 1945, p. 243). 17 Comfort Cooling with Attic Ventilating Fans, by G. B. Helmrieh and G. H. Tuttle (A.S.H.V.E. Transactions, Vol. 40, 1934, p. 155). A.S.H.V.E. Research Report No. 979--Study of Summer Cooling in the Research Residence for the Sum mer of 1933, by A. P. Kratz and S. Konzo (A.S.H.V.E. Transactions, Vol. 40, 1934, p. 167). A.S.H.V.E. Research Report No. 1198--The Effect of Attic Fan Operation on the Cooling of a Structure, by W. A. Hinton and A. F. Poor (A.S.H.V.E. Transac tions, Vol. 48, 1942, p. 145). The Installation and Use of Attic Fans, by W. HBadgett (Agricultural and Mechanical College of Texas, Bulletin No. 52, 1940). Some Effects of Attic Fan Operation on Comfort, by W, A- Hinton and W. G. Wana- maker (A.S.H.V.E. Transactions, Vol. 50,1944, p. 371). BIBLIOGRAPHY The Centrifugal Pumps and Blowers, by A. H. Church (John Wiley & Sons). Fan Engineering, Buffalo Forge Co. Fans, by Theodore Baumeister, Jr. (McGraw-Hill). The Theory and Performance of Axial Flow Fans, by Curt Keller, Adapted by Lionel S. Marks and John R. Weske (McGraw-Hill). CHAPTER 34 AIR CLEANING Atmospheric Air Cleaners: Airborne Particulate Matter, Viscous Impingement 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, Electronic Precipita tors, Adsorbers, Absorbers, Combustion Devices AIR cleaning devices remove contaminants from an air or gas stream. x\ They are ayailable in a wide range of designs to meet various air cleaning requirements. Degree of removal required, quantity and char acteristics of the contaminant to be removed, and conditions of the air or gas stream will have a bearing on the device selected for a given applica tion. Definitions and a discussion of contaminant characteristics are given in Chapter 8, together with some consideration 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 Gleaners are ordinarily used to remove particulates such as are found in outside air, and are employed 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 ventilation where the particu late 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--ATMOSPHERIC AIR CLEANERS Conventional air filters and electronic air cleaners are installed in air handling systems to remove dusts. These dusts constitute a mixture of particle sizes within the classification of temporary and permanent im purities listed in Fig. 1, Chapter 8, including bacteria, pollens, house dusts, and similar allergens which motivate attacks on persons of allergic sensitivity.* 2 .. 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 apparatus. Atmospheric dusts are mixtures uf particles in all sizes. The removal of these particles and fractions becomes progressively difficult as the particle size decreases. Smoke Particles are of major importance in many applications. Air cleaners w*h justify their cost through a reduction in housekeeping expense in the 751 752 CHAPTER 34 1954 Guide ventilated space, by the protection of the equipment in the ventilation system itself, and by providing relatively dust-free air for critical manu facturing processes. Cleaning devices for atmospheric air are classified by the principle employed to collect dirt particles: i.e. impingement on viscous coated media, filtration through porous media, or electronic air cleaning. In some cases a filter may display a combination of these principles. Each type of air cleaner has certain advantages. There are applications where it is desirable to pass air through a series of two or more different types to obtain optimum results. . . AIRBORNE PARTICULATE MATTER Suspensions of particulate matter in the air are called aerosols and con sist of smokes, dusts, mists, and fumes. The characteristics of the aerosols which affect the performance of an air cleaner include particle size, con centration, shape, density, velocity, and surface characteristics. One of the most important 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 appear 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 ordinary 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 material and even such living organisms as virus, bacteria,3 and fungus spores. This wide variety makes it impossible to design one type of cleaner which will be best for all applications. Mechanical filters of the low pres sure 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 contamination, with a low operating pressure drop. As a general rule, the removal of the coarser dust particles and lint from the ventilating air produces tangible results in so far as cleanliness in a house or building is concerned, because much of the finer dust remains Air Cleaning 753 suspended in the air and is removed from the building by the circulating air. However, since some of the fine dusts, especially smoke and fume particles, are undoubtedly deposited by means other than settling, such as electrical or thermal precipitation4'6 and by .contact, the ability to re move small particles is desirable in an air cleaner if it can be obtained at not too great a cost. VISCOUS IMPINGEMENT 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 medias. The filter may be of the unit type manually-cleaned, the replaceable type, or the self-cleaning type. The medium in a viscous impingement type filter is usually 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, in tended 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 small 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 cleaners of this type are: (1) its surface tension should be such as to produce a homogeneous film or coating on the filter medium; (2) the vis cosity should vary only slightly with normal changes of temperature;.(3) it should prevent the development 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) evaporation 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, similar 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 discharge than on the approach side, in order to increase tfie dust holding 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 also increased. Hue to pjane surface area the viscous impingement type filter, however, lminaty. be inferior to some dry types if the air carries a high percentage of ' 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 0.2 in. water, when the device is new and clean, are usual for ventilation system filters. . . Filters designated as high velocity units are also available. In most instances these filters employ a uniform media pack and give best per formance at velocities about 500 fpm. Impingement type air filters should hold a substantial amount of adhesive so that the dirt collected by the filter will be retained. The design and construction should also provide a goodly proportion of free space through the media so that high velocities ^.n be used without excessive resistances. The design should assure that the media throughout the thickness of the filter will be effectively utilized 754 CHAPTER 34 1954 Guide and therefore, the filter should be designed to minimize the formation of a clogging dirt mat on the filter face. High velocity filters arfe 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 which ordinarily necessitates 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 indicate the pressure drop across filter banks, and they serve to indicate when the filter requires cleaning. The pressure drop tolerated differs between operators and system designs. The resistance of a filter bank can be kept desirably low by periodically servicing 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 differs for differ ent 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 materials, and are designed to be discarded after one period of use. The frame is frequently a combination of cardboard and wire. Cleanable filters usually have metal frames. Various cleaning methods have been recommended including: air jet, water jet, steam jet, washing in kerosene, and dipping in an oil. The last may serve both to clean the filter and add the necessary adhesive. It is not mandatory that unit filters be removed from their metal frames for cleaning outside of the system. Cleaning of unit filtersin place is feasible by means of hot water sprayed from a hose or by means of fixed nozzles to accomplish washing 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 In the moving-curtain air filter, means are provided to remove the dust from the medium mechanically. Filters with moving cloth media are available essentially for lint removal. The medium in a typical moving-curtain filter at present consists of a series of specially formed metal plates mounted on a pair of chains. The chains are mounted on sprockets located at the top and bottom of the filter housing, so that the filter medium can be moved as a continuous curtain up one side and down the other side of the sprockets. The arrange ment is such that, at the bottom, the medium passes through a bath of special oil which both serves to remove 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 overlap each other, and due to their special shape, many small air passages are formed between them. These air passages turn abruptly one or more times in order to give the impingement effect. . 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 pressure drop, may be used to govern its motion. In operation, the resistance of an automatic filter will remain Air Cleaning 755 approximately constant as long as proper operation is obtained. A resistance of in. water at a face velocity of 500 fpm is typical of this class. , DRY AIR FILTERS The media in such 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 square unit may contain from 15 to 30 sq ft of medium. Dry air filters, by virtue of the large area of medium used, have a com paratively high lint holding capacity. The efficiency 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 impingement filters. Effi ciency with very fine particles equivalent to that of electronic air cleaners is not uncommon with certain types of dry filters. A comparatively deep bed, H to-1-in. thick, of filtering media having individual fibers in the order of 1 micron in diameter, is required for such high efficiency. Dry filters may consist of a cleanable medium held in permanent frames, or a throw-away or replaceable filtering medium held in permanent frames, or the entire filter may be of the throw-away type. Usually the filter ing medium alone 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 Cleaner Electronic air cleaners use electrostatic precipitation principles to collect particulate matter, see Fig. 1, but operate on much lower voltages than the type commonly used on industrial 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 mo mentary shock to personnel 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 operating from a 110-120 volt, 60 cycle, single phase building service. Electric power consumption is about 10 watts per 1000 cfm, plus the approximately 40 watts required to energize the rectifier tube heaters. Air cleaners of this type offer negligible resistance to air flow and, 756 CHAPTER 34 1954 Guide 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 uniformly over the cross-sectional area. The efficiency of the electronic air cleaner is sensitive to air velocity, and the device 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 Air Cleaning 757 means are employed. The dielectric filtering medium may consist of glass fiber mat, cellulose mat or other similar material; and is. supported on or in contact with a gridwdrk 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 toward 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, clean; on the order of 0.10 in. of water at 250 fpm velocity and, unlike the ionizing type, the resistance of the charged media type electronic cleaner rises as dust is accumulated on the media. Because of these characteristics the filter tends to equalize the air distribution over the face of the filter. Like Fig. 1. Diagrammatic Cross-Section of Ionizing Type Electronic Air Cleaner outside 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 removal 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 avail able 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. The1 bottom of the equipment is made water tight and provided with" a drain. In one moving-plate type, the grounded elements on which the dirt collects are mounted 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 ionization Fig. 2. uuvaiuu juiauoAin ur VOAXIUJ ' Electronic Air Cleaner typical replaceable media mechanical filters, the charged media precipitator is serviced by replacing, the filtering medium. The dielectric. properties of the media are impaired when the relative humidity exceeds 70 percent. AIR FILTER PERFORMANCE AND TESTING Air filters are generally rated in terms of the total air flow for which they are designed, expressed in cubic feet per minute. Face velocity is defined as the average velocity of the air entering the filter, and it is determined by taking the air flow and dividing it by the area of the duct connection to the cleaner in square feet. Filters are often rated at a face velocity, in the range of 250 to 500 fpm. Resistance to air flow is usually measured in inches of water column. The resistances of filters when new and clean, and when operated at rated capacity, are generally available from the manufacturer (see Catalog Data Section). A suitable allowance should be made in system design for increase of filter resistance due to the accumu lation of dust. The ability of air cleaners to clean air is called the efficiency or the arrestance, and may be denoted by the symbol E. The efficiency of an air 758 CHAPTER 34 1954 Guide cleaner differs with the size and nature of the dust on which the cleaner operates. The efficiency of an air cleaner, algebraically expressed; is E= (1) where Di -- amount of dust per unit volume in uncleaned air. Z>2 = amount of dust per unit.volume in cleaned air; .. Several methods have been investigated for evaluating Z>i and D2. The particle count method is not used for efficiency evaluation, except in in vestigation of filter performance on specific particles such as pollen, or on certain industrial dusts harmful to health. Dust particles can be captured on microscope slides by means of one of the various kinds of impingement devices. The process is useful if inspection and analysis of dust are de sired, but particle counting is not sufficiently precise for evaluating the efficiency of a cleaner operating on a heterogeneous dust. The weight method of evaluating efficiency was recognized by The American Society of Heating and Ventilating Engineers and in corporated in a code. For this test, a known weight of a prepared dust is injected into air supplied to the filter, and the quantity of dust in the cleaned air is determined by extracting and weighing the dust from a known volume of the cleaned air. Dust extraction from the air is ac complished by drawing the air through a porous crucible or thimble by means of a high vacuum. . Caution is to be exercised in interpreting published air filter arrestance data, since the test efficiency may be somewhat higher than that which will be obtained in an installation with respect to the ventilated space. The dmt-spot or blackness test for cleaner efficiency was developed at the National Bureau of Standards.'' The test consists of drawing samples of cleaned air and of uncleaned air through filter papers simultaneously. One such test apparatus consists of a means of drawing samples of air simultaneously through two filter papers, one on each side of a light cham ber. The intensity of light from a single bulb passes through these papers and falls on two photo-cells. The cells are connected to the same gal vanometer and if the light falling on one cell decreases faster than the light falling on the other, the galvanometer moves oS the zero position. The flows of air through the filter papers are kept in such ratio as to keep the galvanometer on the zero position, showing that the papers are be coming dirty at equal rates. The ratio of the sampling rates is then an index to the efficiency of the filterunder test.7 Actual atmospheric contami nation is commonly used as the basis of test. The National Bureau of Standards has also used prepared dust and lint in its air cleaner testing apparatus, two injectors for contaminant being used. One injector is used to contaminate the air stream with Cottrell precipitate, previously described. This dust is used to make both effi ciency determination and dust-holding capacity tests. The other injector contaminates the air stream with cotton linters with which lint-holding capacity tests are made. The curves in Fig. 3 illustrate the difference in the characteristics of two filters, one a viscous-impingement type and the other a dry filter with a cellulose fiber medium. The two injectors can be operated either separately or simultaneously. Air Cleaning 759 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. Determination of dust-holding capacity is an objective of each test under the A.S.H.V.E. Standard Code.6 Curves are obtained during such tests to show the relation between dust load and resistance. Fig. 4 indicates the range of resistance to air flow found in tests of four unit air filters. Type A is a dense pack used in bacterium control; Type Bi is a medium pack used for general ventilation work; Type C is a low re sistance unit, for use where low resistance is the important factor and maximum cleaning efficiencies are not essential; and Type D is a highvelocity viscous-impingement filter. Fig. 3. Dust and Lint Holding Capacity of Two Filters SELECTION AND MAINTENANCE To evaluate filters and air cleaners properly for a particular 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 afffect initial costs, operating costs and the extent of maintenance that will be required. Savings that accrue through reduction in house keeping expenses, protection of valuable property and equipment, ability to carry on dust-free manufacturing processes, improved working condi tions, 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 features. Operating costs, predicted life, and efficiency are more important than first cost, because air cleaning is a continuing process. While electronic air cleaners have a higher first cost, they exhibit very fi'gh 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. System resistance remains unchanged as dirt is being collected, and the 760 CHAPTER 34 1954 Guide 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 attention 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 arrestanee may not be any higher. - : ' : ' ' : Unit filters constitute the majority of air cleaners now in use, and some choice is possible between the types available. Where lint in an eminently dry state predominates, a dry filter obviously may be preferable to other 4. Ain AFig. Resistance to Flow of Four Unit ir Filters types because of its lint-holding capacity. If the lint is greasy, or if oil vapor exists in the air, the dry filter, if it is of the cleanable type, may be troublesome, since grease tends to make 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 size, and. their overall dimensions are small when compared 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 V Many air cleaners are available in units of convenient size for handling when installing, cleaning, or replacing. Such units are usually designated Air Cleaning ?6l as filtersor 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 intake ducts, of buildings, and generally in the'recirculating and by-pass air ducts as well. Cleaners are logically placed ahead of heating or cooling coils and other air conditioning equipment in the system to protect them from dust. The character of the dust arrested by the filters in an air intake duct is likely to be mostly particulate matter of a greasy nature, while lint may pre dominate 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 uni formly over the entire filter surface, using baffles or diffusers if necessary. Failure of air filter installations to give satisfactory results can, in most cases, be traced to faulty installation or improper maintenance or both. The most important requirements of a satisfactory and efficiently oper ating 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 increase, a larger filter should-be installed. 2. The filter must be suited to the operating conditions, such as 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 minimum. . 3. Access doors of convenient size should be provided in the sheet metal connec tions 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 niter. . . -. . . .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 10 give a warning when tbe filter resistance 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 contem plated. It is possible that combustible filtering media may not be per- mtted in accordance with some existing local regulations.. Combustion 762 CHAPTER 34 1954 Guide of dust and lint on a filtering medium is possible, though the medium itself may not bum. . > ADSORPTION OF VAPORS OTHER THAN WATER Many of the foreign gases.in the atmosphere are selectively 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 putrefaction. . 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 materials 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 reactivation, 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 organic 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 by-pass effect which depends on the physical arrangement of the charcoal containers. This by-passing 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 is determined by dividing the requirements for contaminant-free air, minus the outdoor air, by the fraction denoting the percentage removal of the gas in question in the adsorber bank which is to be used. :i 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 processing. Adsorber beds, in all cases, should be pro tected from dust, free oil and grease. PART H--INDUSTRIAL AIR AND GAS CLEANERS ; Industrial development and growth of industrial areas have had a. cumulative effect upon the problem of controlling contaminants. Not. only has the atmosphere in many cities become more polluted, but the intensity of pollution 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 housewives, 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 at mosphere, some type of collector is required. An industrial air clean ing installation is designed to perform one or more of the following 6/ functions: y<i 1. Prevent a nuisance or physical damage to an individual, a plant, or adjacent property. * Air Cleaning 2. Prevent re-entry of contaminants to working spaceB. 3. Reclaim usable material. . 4. Reduce fire, explosion, or other hazards. 5. Permit recirculation of cleaned air to working spaces. 6. Allow utilization of cleaned gases for processes. . 763 , DEGREE OF AIR CLEANING REQUIRED The amount of material which can be discharged is established by local or state regulations prepared by pollution control, labor or health depart ments. 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 atmosphere is below the permissible limits of concentration and visi bility. Plant location, contaminants involved, and meteorological condi tion of the areas must be evaluated in addition to existing regulations or codes of good practice^ Fire 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 providing 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 useable 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 refcirculation is considered poor practice and is prohibited by many regula tions where toxic materials are involved, except for those cases where discharge to atmosphere is impossible or decidedly impracticable. Where air is recirculated, its contamination must not exceed the established maximum allowable concentrations listed in Chapter 8. Usual require ments are a fraction, often to x/i, of this standard, depending on: regu lation involved, air quantities recirculated in relation to the cubical content 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 application requires an Valuation of the following 5 considerations: h Concentration, particle size, and size distribution of the contaminant. 764 CHAPTER 34 1954 Guide 2. Degree of cleaning required. . 3. Conditions of air or gas stream with reference to temperature, mbisture content, and chemical composition. ., '. ,. - 4. Characteristics of the contaminant, corrosiveness, solubility,: 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 pf these variables, all available, test data, applica tion experience, and manufacturers'. performance data should be considered. TYPES AND APPLICATION There are a number of principles'involved in the. operation of industrial air and gas cleaners. They are illustrated by the following types of cleaners: . ' 1. Inertial Separators (Gravitational or inertial force,principle): Baffle Chambers, > Centrifugal Collectors. . . . :. . . 2. Scrubbers and other Wet Collectors: Air Washers-, Wet Filters or Packed Towers; Spray Towers, Centrifugal or Inertial Scrubbers, Venturi Scrubbers. V 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 combina-; tion. The important characteristics of any unit are: its collection effi ciency, resistance to air or gas flow: (power requirements), ability to; main tain specified air or gas flow during its operating cycle, and maintenance requirements. . ; ` V ' ' ... In relation to industrial air cleaners, efficiency of collection 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. Occasionally 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 floss of visibility is the major problem, light opacity measurements may be required. From a hygienic viewpoint where air is to be; recirculated, only the contaminant concentration in the recirculated air stream, rather than the correction efficiency, should be considered. (' Correlation between the various efficiencies is poor due to the wicle 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 col lectors--up to 2 in. water; medium 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 sincethese devices are also air movers and therefore the factor of paramount importance is the overall power consumption of the unit. This is als true of certain types of wet collectors which require auxiliary pumping power. . . The ability of any unit to maintain specified air or gas flow during iff operating cycle is also a function of its operating principle. ' For example, Air Cleaning 765r inertial Collectors of the simple and centrifugal type ;are able to maintain constant resistance regardless of concentration and particle size. However,, adhesive materials may collect at , the entry, throughout the unit, and at the exit, and thus cause a reduction in air flow, and serious maintenance problems. With the exception 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 compart ments, 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 precipitators have the outstanding char acteristic of. maintaining., a constant air flow with an accompanying low resistance. Adsorbers behave similarly to packed towers in that they provide constant resistance until the voids become seriously plugged with inert dusts. Thisigenerallyrequires 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 maintenance 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. 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 mechanism, of 'separation in wet collectors depends on inertial forces such as impaction and impingement,' and in some cases, diffusion. . - Wet collectors do not. require any special construction for high temper atures. They are suitable for use on mixed contaminants such as gases and solid or liquid particles. The collection of dust in a wetted form elimi nates a secondary dust problem in disposal of collected material. Pro tection against Corrosion and freezing may be necessary and-disposal of waste liquids may become a problem. With the exception of the packed 766 CHAPTER 34 1954 Guide towers and wetted filters they .all have a constant resistance during their operation. '' / On the basis of their important characteristics wet collectors may be classified according to Table 2. FILTERS Filters for industrial air and gas cleaning consist primarily 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 Table 1. Inertial Separator Characteristics ` Efficiency Particle Size Range In Micbons . , * >100 100-10 <10 Resist - ANCB . (Pressure DrOp) - Description and Remarks Settling and baffle chambers Medium Low Low Large diameter cyclones High Medium to Low Low Low Low . A large chamber to reduce velocity to permit settling. Auxiliary baffles are sometimes used to improve performance Requires large space Considered as single body over 3 ft in diam eter -. > Gases and material must be dry. Air-tight dust bins or continuous removal of mate rial must be provided. Space require ments moderate Refined design centrifugals Integral rotor type Slotted scroll fan High High High High Medium to low Medium Available as multiple small diameter tubes, ' scroll shaped bodies, and multiple louvera Gases and material must be dry. Air-tight dust bins or continuous removal of mate rial must be provided. Space require ments moderate High Medium to low See remarks Rotor acts as air mover and separating ele ment . . Usually limited to dry granular materials and dry gases. Low space requirements No external pressure loss involved but Ppw'er requirements are higher than usual er- hauster Medium to low Low See remarks Separation takes place in fan scroll .- No external loss involved but power require ' ments are higher than usual exhauster bags or tubes. Cloth filters depend to a great extent on the accumulated dust 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. Removal of the col lected material is accomplished through periodic shaking by single mecha nisms or combinations of them employing rapping, or through reversal ol air flow, or by means of high velocity reverse air jets. With shaking oj 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 dependen upon the aerosol, fume, or dust being collected. The ultra or absolute type of filter8 may consist of pleated cellulose as* 768 CHAPTER 34 1954 Guide bestos paper, deep sand beds, composite glass wool layers, cqmpressed glass fiber in the form of paper or batts and resin wool. The Use of this type of filter is limited 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'200F. A wide variety of natural and synthetic filter medias is available for various temperature and corro sion 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 handling toxic contaminants. ! :. Table 3. Characteristics of Fabric Filters Efficiency ; Particle Size Range in Microns ' Resistance In Water Filtering Velocity - . fpm >10 Cloth collector (shaken or rapped)* ; High Cloth collectors ' High (reverse air or' jet cleaning)** Absolute type6 High 10 TO 1 High High High <1 ` -- Moderate to . high Medium ' .1-6 Moderate to Medium to high . , High . ` ' 10-35 , High Medium 3-14 Maintenance Medium to high . Cperiodic) .. Medium to low None (see' -V remarks)';;. :' *b SSppaaccee rreeqquuiirreemmeennttss lmaregdei.umR.eqCuliereasnsincghecdounlsetdancltedaunriningg. oper,ating c'yc le-. Added hors- epower used for reverse jet action. ' . .' ,, . .. : " c Space requirement small. Requires replacement of unit when predetermined resistance is attained Ordinary cleaning not possible. : ; i'i " On the basis of their important characteristics,; fabric filters may fie classified-according to-Table 3. - - ..................... ' 5 ' '; ,. :' ; -i ; ELECTROSTATIC PRECIPITATORS Electrostatic precipitators for industrial air and gas cleaning differ ma terially from the low voltage designs described in Part I of this chapter, although the principles of operation are similar.- For industrial concen trations, it is obvious that more severe demands are made upon methods of cleaning the collector, disposal of collected material, and servicing prac tices. Low voltage cleaners for industrial loadings to' date do not have sufficient inherent dust holding capacity.; One exception in the field of ex haust systems is that of the oil mist collector, which functions satisfactorily bn a liquid aerosol with the conventional low voltage type (2 stage) electro-' static precipitator. ' ; . Industrial precipitators employ an assembly of parallel collector elec trodes of various constructions; including corrugated plate, rod curtains, or perforated plate. Air flow is usually horizontal, although special con struction may permit vertical air flow. High voltage collectors were made.jn the form: of vertical pipes, and are used for high operating pressures and . for wet collector designs where water continuously flows downward inside: Air Cleaning 769 the pipe walls of the collector electrode. The negative discharge elec trodes or rods are accurately centered between the usual 9 in. collector electrode spacing, the latter being of positive charge. Precipitation occurs in a single stage wherein ionization and collection are carried on simul taneously 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 positive chargedcollector plates. Air velocities vary from 240 fpm to 480 fpm with a constant pressure, drop of less than % in. water. Since the maximum efficiency is ob tained 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 equipment rather than the collector. Although usually used for elevated temper ature work, unless the gases are pre-conditioned,. 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 per cent. 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 problems 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 described are intended primarily for particulate removal with the exception of the spray or packed towers or wet cell devices. Absorption devices are intended primarily for the removal of readily soluble gases which can be removed by simple absorbing agents such as water or alkali; for example, the removal of hydrochloric acid gas by a caustic spray. . Adsorption apparatus is intended primarily for removal of organic vapors either high concentration (solvent recovery) or low concentration (odor removal). The first process is usually carried on as a matter of economic recovery. In the second process, the concentration of the contaminant must be low enough so that the adsorbent will have a reasonable life before replacement or reactivation. Combustion, either total or catalytic, may be used to destroy organic 770 CHAPTER 34 1954 Guide compounds, either gaseous or particulate, which create odor problems. The use of catalysts to reduce the temperature needed for combustion is comparatively recent in this field. In some instances the heat of combus tion may be recovered for utilization. The temperature necessary for destruction of compounds varies with the nature of the contaminant. However, partial combustion may alter the compound to render it in nocuous. The temperature required for complete destruction is usually above 1100 F. Catalysts may only require heating to 500 F or may oper ate without heating if the gas temperature is above 500 F. Absorbers These may consist of spray chambers, packed towers, or wet cell washers through which an absorbing agent is recirculated. The gases collected may be converted to insoluble salts or usable acids and other compounds. The performance of these devices depends upon several factors such as the solubility of the gas, its vapor pressure, its rate of reaction with the ab sorbent, the velocity through the collector, area of the absorbing surface either as spray droplets or wetted media. These are generally designed for the specific purpose intended. They usually are intended to collect over 95 percent of the contaminant. Resistance depends upon the par ticular design and ranges from 1 to 10 in. of water in most installations. Their resistance during their operating interval is constant unless serious plugging of packing occurs. Spray units are seldom affected by plugging. Packed absorption devices require a precleaner to remove particulates if long trouble-free service is desired. Maintenance of spray nozzles is a function of the degree of atomization used and of conditions encountered, such as purity of spray liquids. Protection against corrosion and freezing may be necessary and disposal of waste liquids may create secondary problems. Adsorbers These units consist of a chamber filled with a granular adsorbent. The adsorbent may be activated charcoal, silica gel, alumina and other treated solids. Activated charcoal is the most common and has the highest re tention per unit weight for organic solvents. Performance of adsorbent beds 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 inorganic gases. They may be reactivated by the use of steam or heat. Resistance depends upon the adsorbent mesh size, depth and velocity. It may range from less than one inch of water to several inches of mercury. Adsorbent beds are usually limited, because of their cost, to applications where recovery may be economically feasible. Removal of particulate, matter by use of precleaners is necessary if significant loadings are involved as the adsorbent voids are readily plugged. They are not suitable for high temperature conditions. Silica gel and alumina exhibit a strong preference for water vapor whereas charcoal does not. Combustion Devices This group of industrial air cleaners entails the use of high temperatures or catalysis combined with some elevation in temperature to destroy orde' compose organic and some inorganic gases which create obnoxious odors- Air Cleaning 771 The devices are divided into those in which combustion is obtained by use of liquid or gaseous fuels and the secondary air for combustion is provided by the contaminated air. In essence, the simplest form involves passing the contaminated air through the combustion chamber of a boiler or fire box. Special fire boxes or brick checkerwork may also be employed. Catalytic devices consist of noble metal packed into frames in the form of ribbons or screens or may be ceramic granules coated with noble metal catalysts. The frames or packing are placed in a housing over which the gas stream to be decontaminated is passed. The contaminants break down and are reduced to elemental gases of an innocuous nature. Catalysts reduce the amount of heat necessary but may become contaminated by sulfur or other elements. The performance of a combustion device is dependent upon the reten-. tion period of the contaminant in the high temperature zone. Removal or destruction is thus dependent on velocity and surface area of the heat transfer device. If properly designed, obnoxious odors are removed. . The resistance of the direct combustion unit is negligible since it is an integral part of the fuel combustion system. Catalytic devices behave in a manner comparable to packed beds or filters except that they are not plugged by organic particulates but may be affected by inorganic solids. Maintenance of these types of units is essentially dependent upon the contaminants encountered. The direct combustion system requires little care other than that required by ordinary fuel burning equipment. Cata lytic units become contaminated slowly and will require removal for re activation at certain intervals depending upon the application. Economic factors may limit the use of direct combustion methods unless there is a demand for the heat generated. They may best be applied to processes employing combustion. Catalytic units require temperatures of at least 500 F and consequently it may be necessary to preheat the con taminated air to this value. REFERENCES Mn?7ial A?thm? and AiHed Allergic Disorders, by S. S. Leopold and C S wpoia {Journal of the American Medical Association, March 7,1925, Vol. 84, p. 731- 1 Air Cleaning as an Aid in the Treatment of Hay Fever and Bronchial Asthma, by Leo H. Criep, M.D., and M. A. Green, M.D. (Journal of Allergy, St. Louis, Janu ary, 1936, Vol. 7, No. 2, Page 120). . ' The Bacterial Filtration Efficiency of an Electrostatic Air Cleaner, by O. M. Lidwell (Journal of the Institution of Heating and Ventilating Engineers, 75 Eaton p`ace, London, S.W.I., June 1951, Vol. 19, No. 190, Page 139). * Dirt Patterns on Walls, by R. A. Nielsen (A.S.H.V.E. Transactions, Vol. 46,' Wl, p. 247). ` Industrial Dust, by Philip Drinker and Theodore Hatch (McGraw-Hill Co., New York, N. Y.). ,, ` A.S.H.V.E. Standard Code for Testing and Rating Air Cleaning Devices Used in General Ventilation Work (A.S.H.V.E. Transactions, Vol. 39,1933, p. 225). v ! Test Method for Air Filters, by Richard S. Dill (A.S.H.V.E. Transactions, vb 44, 1938, p. 379). Laboratory Design for Handling Radioactive Materials, Research Conference ^PW-^Building Research Advisory Board, National Research Council, Washington, BIBLIOGRAPHY Design and Application of Oil-Coated Air Filters, by H. C. Murphy (A.S.H.V.E. ^nsactjons, Vol. 33, 1927, p. 73). 772 CHAPTER 34 1954 Guide ( . .Operation and Maintenance of Air Filters, by W. G. Frank (Heating, Piping and Air Conditioning, May, 1931, p. 378). , Size and Characteristics of Air-Borne Impurities, by W. G. Frank (Heating, Piping - and Air Conditioning, January, 1932, p. 35). Fundamental Principles in the Design of Dry Air Filters, by Otto Wechsberg (A.S.H.V.E. Journal Section, Beating, Piping and Air Conditioning, April, 1933, p. 2T1h7e). Economic Factors in Converting Recirculated Air for Ventilation, by H. E. Zi'el and Henry Sleik (A.S.H.V.E. Journal Section, Beating, Piping and Air Condi tionAi.nSg.,HJ.Vul.yE,. 1R94e3s,epa.bc3h67R). eport No. 1094--Air Filter Performance as Affected b.y Kind of Dust, Rate of Dust Feed, and Air Velocity Through Filter, by F. B. Rowley and R. C. Jordan (A.S.H.V.E. Transactions, Vol. 44,1938, p. 415). . A.S.H.V.E. Research Report No. 1122--Air Filter Performance as Affected by Low Rate of Dust Feed, Various Types of Carbon, and Dust Particle Size and Den sity, by F. B. Rowley and R. C. Jordan (A.S.H.V.E. Transactions, Vol. 45, 1939, p. 339). . ., A.S.H.V.E. Research Report No.1145--The Effect of Lint on Air Filter Perform, ance, by F. B. Rowley and R. C. Jordan (A.S.H.V.E. Transactions, Vol. 46, 1940, p. 25). .' ' . A.S.H.V.E. Research Report No. 1169--Comparison of the Weight, Particle Count and Discoloration Methods of Testing Air Filters, by F. B. Rowley and R. C; Jordan (A S H.V.E. Transactions, Vol. 47, 1941, p. 29). A.S.H.V.E. Research Report No. 1187--Economical Air Velocities for Mechan ical Air Filtration, by F. B. Rowley and R. C. Jordan (A.S.H.V.E. Transactions, VoAl. .4S7.,H1.V94.1E,.pR. e3s9e1a).rch Repo.rt No. 1218--Overloadin. g of Viscous Air Filters Dur ing Accelerated Tests, by F. B. Rowley and R. C. Jordan (A.S.H.V.E. Transactions, VoAl. 4N8e, w19E42le, cpt.ro4s3t7a)t.ic Precipitator, by G. W. Penney (Electrical En.gineering, Jan uarEyl,e1c9tr3o7s,tpa.ti1c59P).recipitation for Aircraft, by Howard E. Corbitt and Norman J,; Clark (Aero Digest, December, 1940, p. 132). Pointers on Selecting Equipment for Industrial Gas Cleaning, by C. E. Miller (Chemical and Metallurgical Engineering, 45, March, 1938, p. 132-5). ' Electrical Precipitation, by W. A, Schmidt and E. Anderson (Electrical Engineer ingE, l5e7c, tAricuagluPstr,e1c9ip38it,apti.o3n3, 2b-3y3A8).. W. Simon and L. C, Kron (Electrical Engineering, 61- ,SFoemberuFaarcyt,o1rs93a2n, dp.P9r3in-5c)ip. les Involved i'n the Separation and Collection of Dust, Mist and Fume from Gases, by Evald Anderson (Transactions, American Institute of Chemical Engineers, 16, 1924, Pt. 1, p. 69-86). . Electrical Precipitation of Solids from Smelter Gases, by Ross B. Rathbun (Trans actions, American Institute of Electrical Engineers, 41, 1922, p. 815). Characteristics of Unit Dust Collectors, by Arthur C. Stern, Jack Baliff, Arthur E. Perina, Robert Crowley, Benjamin Feiner and Arthur A. Urbano (A.S.H.V.E- Journal Section, Beating, Piping and Air Conditioning, May, 1946, p. 117). Operation, Application and Effectiveness of Dust Collection Equipment, by John M. Kane (Beating and Ventilating, Reference Section, August 1952). Air Pollution Abatement Manual--Chapter 9, by C. A. Lapple (Manufacturing CheBmanisdtsboAosksoonciaAtiiornC).leaning, by Sheldon K. Friedlander, Leslie Silverman, Ph ilip . Drinker and Melvin W. First. (U. S. Atomic Energy Commission, Washington, D. C-i- Performance of Wet Cell Washers for Various Aerosols, by M. W. First, R. chella, L. Silverman, and E. Berly (Industrial and Engineering Chemistry Vo1. *>, 195C1h, epm. i1c3a6l3E).ngineers Bandbook, by John H. Perry. (McGraw-Hill Book Co., ^. Edition 1950). American Industrial Bygiene Association Quarterly, March 1950. . Design Factors in Catalytic Fume Elimination, by R. J. Ruff (Beating and Venti lating, September 1953, p. 84). CHAPTER 35, SPRAY APPARATUS Air Washers, Humidification with Air Washers, Dehumidification and Cooling with Air Washers, Well and Water Main Temperatures, Apparatus for Direct . Humidification, Unit Humidifiers, Water-Cooling Towers, Water Use . and Conservation, Rivers and Lakes, Spray Cooling Ponds, Atmos pheric and Mechanical Draft Cooling Towers, Mechanics of At mospheric Water-Cooling, Design Conditions, Water-Cooling Tower Design, Selection of Water-Cooling Towers, Operation and Maintenance AIR humidification is effected by the vaporization of water, and always requires heat from some source. This heat may be added to the water prior to the time vaporization occurs, or it may be secured by a transformation of sensible heat of the air being humidified to latent heat as the vapor is added-to the air. The thermodynamics of the process are discussed in Chapter 3. The removal of moisture from air may, or may not, involve the removal of heat from the air-vapor mixture. With spray equipment, dehumidification of air always necessitates the removal of heat. AIR WASHERS An air washer consists essentially of a chamber or casing in which is provided a spray nozzle system, a tank at the bottom of the chamber for collecting the spray water as it falls, and an eliminator section ,at the leaving end of the chamber for removal of drops of entrained moisture from the delivered air. Air is drawn through the casing of the washer, where it comes into intimate contact with the spray water. A heat trans fer takes place between the air and water, resulting in either humidifica tion or dehumidification of the air, depending upon the method of operation and the relative temperatures of air and spray water. To prevent backlash of spray ahead of the washer chamber, and to aid in more uniform air distribution, inlet diffusion plates or eliminator baffles, where necessary, are provided in the air entrance end of the air washer. Inlet diffusion plates are used when the air flow and water spray are in the same direction; eliminator baffles of special design are used where one or more of the water sprays opposes the air flow. At . the out let end of the washer suitable flooded eliminator plates are used. These plates, for the removal of entrained moisture, usually cause four to six changes in direction of the air flow. . Ugs. l and 2 show the essential construction features of conventional air washers. Intimate contact between the air and the water is secured (1) by breaking the water into fine drops; (2) by passing the air over sur faces continuously wetted by water; or (3) by a combination of the two. The wetted surfaces in an air washer may be of fiber glass, metal or scrubber plate construction. Scrubber plate types of washers are generally used to wash reclaimable. products from the air, and are composed of vral baffle type plates located, across the air stream. Water is supplied t the top of the washer to spray over these plates. In the case of the ber glass or metal surfaces, the water spray is usually rather coarse and at 773 774 CHAPTER 35 1954 Guide low pressure. In many cases these sprays are set at an angle with the air flow. Air washers of this type not only perform necessary heat transfer functions, but also are effective removers of dust and dirt from the air stream. Essential requirements in the air washer operation are: uniform distri bution of the air across the chamber section; moderate air velocity of from 250 to 600 fpm in the washer chamber; an adequate amount of spray water broken up into fine droplets throughout the air stream, at pres sures of from 15 to 30 psig; sufficient length of travel through the water Fig. 1. Typical Single-Bank Air Washer Fig. 2. Typical Two-Bank Ais Washer spray and wetted surfaces; and the elimination of entrained moisture from the outlet air. 7 Expected performances, physical size, length, number of sprays, etc., vary greatly, depending upon the functions of the installation. In general; the width and height of an air washer are dictated by the space available; Washers of nearly equal height and width are desirable from an air flo? and economic standpoint, although not necessary. The length of washers varies considerably. A space of approximately 2) ft between spray banks is used, and the first and last banks of sprays are located about 1 ft to 1$ ft from the entering or leaving end of the washer. In addition, air washere are very often furnished with cooling coils or heating coils within the washer chamber, and the use of these coils affects the overall length of the washer. Where increase of overall heat transfer between the air and watery required, multistage washers are used. These washers are equivalent to a number of washers in series, and the water is often pumped from one stage to the other where conditions permit. r! The resistance to air flow through an air washer varies with the type of eliminator and wetted surfaces, number of banks of spray and their Spray Apparatus 775 direction, air velocity, size and type of other resistances such as cooling and heating coils, and other factors such as air density. Resistances vary from as low as j in. to higher than 1 in. water column, and it is therefore necessary that the manufacturer be consulted in regard to the resistance of any particular washer design involved. 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 dry-bulb temperature less than 35 F in order to eliminate 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 leak from outside into the apparatus, including the pump and its connecting piping, the process would be strictly adiabatic. Evapo ration 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 temperature 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 constant thermodynamic wet-bulb temperature as explained in Chapter 3. The extent to which the final temperature ap proaches 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 effec tiveness, and is defined as where U-t, e>h h-t' (1) eb = humidifying effectiveness, percent. h - dry-bulb temperature of the entering air, Fahrenheit degrees. tt = dry-bulb temperature of the leaving air, Fahrenheit degrees. 1' = thermodynamic wet-bulb temperature of the entering air, Fahrenheit de grees. The following may be taken as representative humidifying or saturating effectiveness of an air washer for the conditions stated: l 1downstream................................................................. 60-70 percent 9 upstream............................... ....................................... 65-75 percent z banks--downstream........................................ ...................... 85-90 percent t "ank--1 upstream and 1 downstream............................. 90-95 percent i hanks upstream.................................................................... 90-95 percent The humidifying or saturating effectiveness of a washer is dependent npon the essential items of design mentioned under Air Washers. Other conditions being the same, low velocity of air flow is more conducive to higher humidification effectiveness. Method 2. The preheating of the air increases both the dry- and wetbulb temperatures, lowers the relative humidity, but does not alter the humidity ratio (pound water vapor per pound dry air). At a higher wet- 776 CHAPTER 35 1054 Guide Table 1. Average Maximum Water Main Temperatures* State City State City ,5 State Ark. Ariz. BiTMmrham .......... kittle Rock ' " ' hoeni*.... .......... A-lnucashoenim........ .......... Berkeley.. .......... : Fresno___ "........... ' ^ulierton.. .......... _LOoisenAdnagieeies.. ` ' ODanktalarniod..,...... ........... Pasadena.. " '" " oroona...... .......... Sftiavcermamideen. to............ WKCrrdin:: . Colo. Conn. ^Brindvgeerp..o-r;.t ........ Hartford IUdla. ho Iowa Ky. La. Me. Md. ^bington'........ Wilmington. " Jacksonville,''''' Tampa................... Atlanta ........ .. " MBoaicsoen........................ Chicago............. CEvicaenros.t.on.............. Moline. ........... Peoria... . '........... Rockford ....... Springfi,.]'^.......... Evansville ........ Liary ........ i"c!"n%poiis.. South Bend Haute.. g>u* City..] voncordia Kansas City ' lopeka. Wichita-... " Louisvilie!.. Baton Rouge J?6w Orleans "hreveport Augusta [ Baltimore.................. Mich. Grand Rapids....'. Highland Park..-.. Jackson___ ....... Kalamazoo......... V. Lansing.................. Saginaw...........: .-. i Duluth................... Minneapolis.--.. St. Paul.____ --\ Jefferson City....... Kansas City ...... Springfield. St. Joseph______ St. Louis....... Springfield___ ,----Lincoln__ :..'-----Omaha......... .'.v. Reno..................... ' Manchester....... Jersey City.......... Newark................. Paterson ............... ' Trenton................ N; Y. .Albany...... .......... Buffalo.................. -Jamaica...! -- .. Mt. Vernon......... New Rochelle.... New York. Rochester............. Schenectady....... Syracuse.............. Utica..................... Yonkers.......-- N. C. Asheville. Charlotte............ Raleigh.............. Winston-Salem.. Albuquerque-- Akron.................. Canton.-.--... .___ Cincinnati......... Cleveland....... Columbus........... Dayton.............. Lakewood.. Springfield......... 60 Toledo.......... . 76 Okla. Oklahoma City. Tulsa...................... Eugene................. Portland............ Altoona................ Erie....................... Johnstown........... McKeesport......... Philadelphia....... Pittsburgh.......... R. I. S: C. Providence.......... Charleston.......... Greenville............ Spartanburg....... S. D. Tenn. Rapid City......... Chattanooga....... Knoxville.......... Memphis.............. Nashville............ Amarillo............ Austin................ Beaumont.......... Dallas................. El Paso.............. Fort Worth........ Galveston.......... Houston............ Port Arthur....... San Antonio -- Wichita Falls.... Logan.................. Salt Lake City.. Fredericksburg.. Lynchburg........ Norfolk.............. Richmond ....... Wash. I Olympia........... Seattle.............. Spokane............ Tacoma............ Charleston....... Huntington.... Wis. Wheeling........... LaCro$se........... Madison............ Milwaukee....... Racine.............. Prov ince Alta.B. C. Ont. P.E.I. Que. I Calgary ..., -- [ Vancouver........ 1 London.............. Toronto.............. Charlottetown.. Montreal............ Quebec............... a These averages taken from various city water main locations, with some-actual values slightly hi8^er and some lower than values shown. Some'values were supplied'by H. E. Degler, Marley Company- o?^e were obtained from City Water Department records. The highest values given by the various authorities are usually those listed.. - bulb temperature, but the same humidity ratio, more water can be ab sorbed per pound of dry air in passing through the washer, assuming that the humidifying effectiveness of the washer is not adversely affected by operation at the higher wet-bulb temperature. 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 en trance to the washer. Method S. Evert if heat is added to the spray water, the mixing occur: ring in the washer itself may still be regarded as adiabatic. The state Spray Apparatus 777 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, hv elevating the water temperature, to raise the air temperature, both dry-bulb and wet-bulb, above the dry-bulb temperature 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 humidity. . DEHUMIDIFICATION AND COOLING WITH AIR WASHERS Cooling of- the wet-bulb temperature of an air vapor mixture can 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 water temperature is lower than the dew-point of the .entering air. In these cases the final dry-bulb temperature and relative humidity of the leaving air are dependent upon the design factors of the air washer. Both sensible and latent heat are removed in the process of dehumidi fication by cold spray water. Abstraction of sensible heat occurs during . the entire time that the air is in contact with the spray medium. Latent heat removal takes place as condensation occurs. Therefore, the lower the spray temperature, the greater the amount of moisture removal per pound of dry air, all other conditions remaining the same. Washers with two or more banks of spray are usually selected for de- humidifying installations, whether for comfort or industrial installations. Generally.such air washers cool the air to within one or two degrees (Fahren heit) of the leaving spray water temperature; this differential will increase somewhat when the difference between the entering wet-bulb and leaving dew-point is relatively large. ` 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 temperatures. Table 1 lists some approximate water main averages which may be used as a guide, but they should be verified from local records. This is particularly true with mty water main temperatures. In the case of well water temperatures, mg- 3 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 recircu lating pumps. These pumps deliver a mixture of cold and recirculated water under the control of a three-way valve. The valve may be actuated either by a thermostat in the washer outlet, or by a humidity or other con troller in the space being conditioned. Air washers for dehumidifying are very often furnished with direct exPansion or water cooling coils within the washer space, in which case Water for the washer sprays is entirely recirculated. APPARATUS FOR DIRECT HUMIDIFICATION Humidifiers may be divided into two general types which are, according fne method of operation: (1) indirect, such as the air washer, which 778 CHAPTER 35 1954 Guide introduces moistened air; and (2) direct, which sprays moisture into the room or introduces moisture by means of steam jets. As in the cases of humidification by use of an air washer, the heat neces sary for the vaporization of the moisture added to the air by direct humidi fication is secured either from heat stored in the spray water or by a trans- V ia . 3. A p p r o x im a t e W e l l W a t e r T e m p e r a tu r e s a t D e p th s of 30 to 60 F t 1 Spray Apparatus 779 formation of sensible to latent heat in the air humidified. In the latter case, the enthalpy of the air remains constant, but the dry-bulb tem perature of the air is reduced. Direct humidification is usually preferable where high relative humidi ties must be maintained, but where there is little cooling or ventilation required. In comfort air. conditioning, where both humidification and ventilation are required, the indirect humidifier is preferable. In indus trial applications, where the cooling or ventilation load is large and where very high relative humidities must be maintained, a combined system employing both direct and indirect humidifiers is sometimes used. Spray Generation Spray generation is obtained by (1) atomization, (2) impact. (3) hy draulic separation, and (4) mechanical separation. Atomization involves the use of a compressed air jet to reduce the water particles to a fine spray. With the impact method, a jet of water under pressure impinges directly on the end of a small round wire. Where hydraulic separation is employed, a jet of water enters a cylindrical chamber and escapes through, an axial port with a rapid rotation which causes it immediately 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 Spray distribution is obtained by (1) air jet, (2) induction, and (3) fan propulsion. . The air jet which generates the spray in atomizers also carries the spray through a space sufficient for its distribution and evaporation, and this method of distribution is termed air jet. Where distribution is obtained by induction, the aspirating effect of an impact or centrifugal spray jet is utilized to induce a current of air to flow through a duct or casing, and this air current distributes the spray. Fan propulsion obviously consists of the utilization of. fans to entrain and distribute the spray. Industrial type direct humidifiers are commonly classified as (1) atomizmg, (2) high-duty, (3) spray and (4) self-contained or centrifugal. . Atomizing Humidifiers. Several types of atomizing humidifiers employ nozzles placed within the room and rely upon compressed air to effect com plete atomization of the water which is converted to vapor by the heat of the room air. Some of these nozzles depend upon an aspirating effect to draw the water into the nozzle and atomize it; others operate on a com bined 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. High-Duty Humidifiers. Water is supplied under high pressure (usually |toout 150 psi) through pipe lines from a centrally-located pumping unit, the spray-generating nozzle, which is of the impact type, is located in a cylindrical casing. A drainage pan provides for the collection and return of unevaporated water which flows through a return pipe to a filter tank, !rm which it is recirculated. A powerful air current is forced through the humidifier by means of a fan mounted above the unit. The air enters from above, is drawn through the head, charged with tooisture, and cooled. It then escapes from the opening below at a high 780 CHAPTER 35 1954 Guide velocity in a complete and nearly horizontal circle. The spray is evapo rated and the resulting vapor diffused. This distribution of fine Spray over the maximum possible area promotes complete arid rapid vaporization. Spray Humidifiers. This type consists of an impact spray nozzle in a cylindrical casing with a drainage pan below it. The aspirating effect of the nozzle induces a moderate air current through the casing which dis tributes the entrained spray. The general method of circulating and returning the water is similar to that employed for high-duty humidifiers. A suitable pump and centrally-located filter tank are required. Self-Contained Humidifiers. The self-contained or centrifugal humidi fier has the ability to generate and distribute spray without the use of air compressors, pumps, or other auxiliaries. These may be used either singly or in groups. In large installations, where suitable connections are pro vided to permit the cleaning and servicing of individual units without af fecting 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. The essential element of a unit humidi fier 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, depending 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 evapo ration is effected by adiabatic exchange of energy. Units 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. In the rotary type of humidifier the spray is created by rotating vanes or discs which throw the water by centrifugal force, and in so doing break it up into a fine mist. 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 liable to become clogged. In the cascade type the humidification takes place by water 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. There are many variations of this type of humidifier. 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 surface. . . WATER-COOLING TOWERS The removal and dissipation of heat from a compressed refrigerant or from exhaust steam are important factors in the efficient operation of & refrigerating plant or an electric steam-generating station. This heat removal is generally accomplished by first transferring the heat of the g Spray Apparatus 781 to cooling water in a heat exchanger. The water, if cheap or plentiful, may be wasted to the nearest sewer or open waterway, such as a river or lake. Where water usage is restricted or expensive, or where the available water contains dissolved salts which would form scale on the heat-exchange apparatus, it is necessary to recirculate the water, and to cool it, after each passage through;the heat-exchanger, by contact with moving air in some type of water-cooling apparatus. Water Use and Conservation Many communities have found that present water systems are not sufficiently large to satisfy the increasing demands of domestic and indus trial users. The reasons for such shortages are primarily: (a) inadequate purification and water-distribution systems; (b) inadequate sanitary and storm-sewer disposal systems; or (c) inadequate sources of water. Even when an adequate supply of water is available from the water mains or private wells, many cities do not have sufficient sanitary or storm sewer facilities to handle increasing demands. The sanitary systems are usually limited because of the capacity of the filtration plants, and therefore many cities restrict the use of the sanitary system to sewage. Rivers and Lakes . ' Until the year 1920, large generating stations were usually located on the banks of rivers, lakes, or artificial ponds. The removal and dissipation of the heat from the Diesel cylinder or the exhaust steam of a turbine was accomplished by taking in the circulating water at a considerable distance from the discharge, thus preventing mixing of the heated discharge with the inlet water. The use of water from streams for this purpose has the following disadvantages: the site may be far removed from the fuel source or from power consumers; water supply may limit plant expansion; munici pal restrictions on use of water may hamper operation; costly intake struc tures with screens and sediment basins may be required; drastic flood or drouth conditions, the vagaries of most rivers, upstream pollution, scale forming constituents, debris, sand, algae, and formation of troublesome ice may cause operating difficulties. When lakes and cooling ponds have been used as a source of circulating water, the hot water is discharged close to the surface at the shore line. Natural air movement over the surface of the water causes evaporation over that area, thus carrying the heat away at a rate of about 4 Btu per vm) (sq ft) (F .deg temp difference between air and water). Increased density of the water due to loss of heat, causes the cooled water to sink to me bottom of the pond. The suction connection is therefore located as far below the surface as possible, and at as great a distance from the dis charge as practicable. The area required by such cooling ponds is about ~0 times that of a spray pond, or about 1000 times that of a water-cooling w>wer to dissipate the same quantity of heat and achieve equal operating costs. If the surfaces of such ponds were below the level of surrounding .terrain, and the shore were wind-sheltered by trees or other vegetation, so inat natural air movement across the surface of the water would be refarded, the use of a spray pond or water-cooling tower would be indicated. SPRAY COOLING PONDS The spray pond consists of a water collecting basin, above which spray 3zles are located in an arrangement such as shown in Fig. 4 to spray 782 CHAPTER 35 1954 Guide the water upwards into the air. Properly designed spray nozzles break the water into small drops, but not into a mist. Since the/objective is to cool the pond water, the individual drops must be heavy enough to fall back into the pond and must not float away in the air. The water surface exposed to the air passing over the pond becomes the integrated area of all the small drops. The spray pond requires about one-fiftieth of the space required by the cooling pond to dissipate the same quantity of heat with equal results, due to four factors: (1) the speed with which the drops are propelled into the air and fall back into the water basin; (2) the increased wind velocity at a point above the surrounding obstruction; (3) the in creased volume of air delivery due to the greater vertical cross-section of air permissible; and (4) the vastly increased area of contact between water and air.2 Spray pond effectiveness is increased by: (1) elevating the nozzles to a higher point above the surface of the water in the basin; (2) increasing the spacing between nozzles of any one capacity; (3) using smaller capacity Spray Apparatus 783 also restrict the flow of air, particularly at the higher wind velocities, thus reducing the possibility of water being carried from the spray cloud. The height of an effective fence should be equal to the height of the spray cloud. Algae formations may be a nuisance in a spray pond. Such growths are minimized by the periodic addition of bromine, chlorine, chlorinated lime, copper sulfate, or various blends of chlorophenates (see Chapter 43). The performance of a spray pond is limited because of space requirements and the probable high cost of piping and pumping. Water-cooling towers, however, allow the designer a wider range of performance within a given space because of the possibility of altering the smaller physical dimensions or varying the water concentration, measured in gallons per (minute) (square foot of tower area). In most cooling towers the water is broken up into drops many times, whereas with the spray pond it is broken up only once, and, consequently, in the latter the rate of cooling diminishes rapidly as the temperature of the surface of the drop approaches the wet-bulb temperature of the ambient air. Table 2. Spray Pond Design Data Fig. 4. Typical Nozzle Arrangement for a Spray Pond nozzles to decrease the concentration of water per unit area; and (4) using smaller nozzles and increasing the pressure to maintain the same concen tration of water per unit area. . It is usual practice to locate the nozzles from 5 to 12 feet above the surface of the water (dependent also upon depth of water and curb level) with water supply at 5 to 7 psig pressure at the nozzles. Nozzles spray from 25 to 60 gpm each, and the nozzles are spaced so that the average water delivered to the surface varies from 0.1 gpm (small ponds) to 0.4 gpm (large ponds) per square foot. See Table 2 for additional spray pond design data. Best results are obtained by placing the nozzles in a long, relatively narrow area, located broadside to the wind. Louver fences, to prevent the carrying of entrained water beyond the edge of a spray pond by the air on the leeward side, are required for all roof locations and for ground locations where space is restricted; the outer nozzles should be located at least 20 ft from the edge of the basin. Such fences up to 12 ft in height usually are constructed of horizontal overlapping louvers supported between vertical posts. The air, in passing between these louvers, tends to be freed of the larger drops of water. The louvers Units Water capacity per nozzle Nozzles per 12 ft length of pipe Height of nozzles above water level Nozzle pressure............... Size of nozzles and nozzle arms..................... Distance between spray lateral piping...! Distance nozzles from pond side unfenced.. Distance nozzles from pond side fenced.. Height of louver fence.. Depth pond tjasin.......... tnotion loss allowed per 100 ft pipe... Hesign wind velocity___ ** ft psig m. ft ft ft ft ft ft mph Standard Minimum Maximum 35 to 50 25 66 g 12 6 2 i 2 25 13 38 25 to 35 20 50 15 to 20 15 25 12 12 4 to 5 1 to 3 5 ATMOSPHERIC COOLING TOWERS Spray-fitted atmospheric cooling towers are used for open-area installations because of their dependence upon the velocity and direction of the wind. Operation is not so limited as with spray ponds, but the design is generally based on a 3 mph wind, and the performance falls off rapidly as the ambient air velocity decreases. These towers require less basin area, less piping, and no more mechanical equipment than spray ponds, but these savings ay be largely offset by the extra cost of the structure. The drift nuisance is similar to that of spray ponds. The word tower used in this connection is a misnomer, as the design simulates a narrow spray pond with length wee the width, or more, having elevated nozzles and a high louver fence. As usually built, the nozzles spray downward from the top of the structure, the distance from the center of the nozzle system to the louvers on either side is not more than half the distance that the nozzles are elevated above the water-collecting basin. Heights range from 6 to 15 ft, with the total width of the structure usually not greater than the height. Loadings range from 0.6 to 1.5 gpm per sq ft of tower area, and hence require about one-fourth the area of an equivalent spray pond. As the louvers are Wetted continuously, they add to the surface of water exposed to the ooung air. The spray-filled atmospheric tower is shown in Fig. 5. ilk ik 784 CHAPTER 35 1954 Guide : Much of the atmospheric water cooling for refrigeration work during the past 30 years has been done with natural-draft deck type towers, also referred to as atmospheric deck towers,--see Fig. 6. These towers consist of a sturdy wooden or steel frame 20 to 50 ft high and 8 to 16 ft wide, carrying, open horizontal wooden latticework or decks at regular intervals from top to bottom. The hot water is distributed over the upper part of the structure by means of troughs, splash heads, or nozzles, and drops from deck. to deck enroute to the basin. The purpose of the decks is primarily to arrest the fall of the water, to break and re-break it into drops so 'ds to present the most efficient cooling surface to the air which is passing through the tower transversely to the decks. The wooden decks also add to the area of water surface exposed to the air, but since they offer resistance Fig. 5. Spray Filled Atmospheric Cooling Tower Fig. 6. Atmospheric Deck Towns to the flow of air, the number and arrangement of the decks depend upon basic-tests and operating experience. To prevent loss of water on the leeward side of the tower, wide louvers (drift eliminators) are attached at regular intervals from top to bottom; these louvers extend outward and upward at an angle of 45 to 50 deg. Ia most designs the top edge of each louver extends above the bottom edge of the one above. These louvers serve the same function as a louver fence around a spray pond, namely, to stop the water drops carried by the a|r beyond the open area of the tower, and to control the quantity of air permitted to pass through the tower. ' The efficiency of a deck tower is improved primarily by increasing length or height, or both, within limits; the length and height increase the area of tower exposed to the wind. The improvement is not directly propor: tional to the change made in either case. Neither does a certain percentage Spray Apparatus 785 change of one dimension make an equal improvement in efficiency on two equal towers of different original lengths or heights. Since the range of efficiency varies through wide limits, it is impracticable to attempt to list data here on the area required per unit quantity of water. Improved efficiency, due to added height, is obtained at the expense of additional pumping head and increased weight per unit of area, whereas improvement gained by greater length or width will increase the area and, consequently, the foundation required. ' Drift loss in a properly designed deck tower is considerably less than in the spray pond, but the drift nuisance may be considerable, and for this reason atmospheric deck towers are unsuitable for downtown building roofs, locations adjacent to buildings, or near expensive mechanical equip ment in industrial plants. They must be located in an open area, broad side to the prevailing wind. They are inefficient with less than 3 mph wind velocity and with wind directions other than broadside. These towers are long and high- in proportion to width, and must be securely anchored to prevent uplift or overturning during high winds. High pump ing requirements (30 to 60 ft) and total dependence upon atmospheric caprice, especially wind (quantity and direction), are disadvantages. Due to new uses and growth of demand in recent years, requirements for water-cooling equipment have become increasingly varied and exacting, necessitating refinements and specialized adaptations. The principal de mand for large water-cooling systems in recent years has come from the petroleum industry and steam power plants. Refrigeration, air condi tioning, and engine-jacket cooling service today employ a large percentage of the medium sized and small water-cooling towers installed. MECHANICAL DRAFT TOWERS The mechanical draft tower consists usually of a vertical shell constructed of wood, metal, transite, or masonry. Water is distributed near the top, uniformly over the area, and falls to the collecting basin in the bottom, passing through air which is being circulated in the tower from bottom to top by forced or induced draft fans, or which is circulated horizontally in crossflow towers by induced draft fans. In vertical towers the air passes counterflow to the water and is in con tact with the hottest water just before leaving the tower; hence, a given quantity of air picks up more heat than the average equal quantity of air on natural draft equipment. This permits the water to be cooled with the least quantity of air required by any type of cooling equipment. As movement of air through the towers is obtained by power-consuming fans, is essential that this air quantity and the draft loss be reduced to a mini mum so as to secure low operating cost. The inside of a mechanical draft tower may be spray filled, i.e., the water surface is presented to the air by filling the entire inside of the structure with water droplets from the spray nozzles, or it may be packed with wood filling, over which the water cascades from top to bottom. In many cases, a cmbination of the spray-filled and wood-filled design is used. The forced draft type of tower (Fig. 7), has the advantages of being suit able for corrosive waters, and having the fan mounted near the ground eyel on a rigid foundation where it is easily accessible. The heated air leaves the top of a forced draft tower at a low velocity fifin may be subject to recirculation to the fan inlet, with consequent reduc- 786 CHAPTER 35 1954 Guide tion in performance. This reduction could be as much as 20 percent under certain conditions. During cold weather, recirculation 'inay cause ice formation on adjacent equipment and buildings, as well as in the tower fan ring, with possible resultant fan breakage. Fan sizes are limited to 12 ft or less, and therefore more fans, motors, starters, and wiring are needed than for induced draft towers. Induced draft towers, since fans and motors are not visible, are therefore somewhat more adaptable to architectural treatment . In the spray-filled mechanical draft tower, the area presented to the air is the combined surface area of the small drops present in the tower at any one time. The net free cross-sectional area of the air spaces in a spray-filled tower is greater than that of the wood-filled tower for the same plan area. Before discharging to the atmosphere, the water-laden exhaust air passes through a drift eliminator to remove entrained moisture. This Spray Apparatus 787 this air is in contact with the water. The surface area of water in contact with the air is increased in both cases. Increasing the air quantity de creases the time the air is in contact with the water, but since a greater quantity of air is passing through, the average differential between the water temperature and wet-bulb temperature of the air is increased, and this speeds up the heat transfer rate. Increased air quantities are obtained only at the expense of increased fan power, which, for fans of the disc type, increases approximately as the cube of the air handled. The performance of mechanical draft towers is independent of wind velocity; hence, it is possible to design them for more exacting performance. Fig. 7. Forced Draft Cooling Tower type of tower is particularly applicable for installations in restricted areas where city ordinances require fire-proof construction. In the wood-filled tower, lumber of various cross sections is laid hori zontally across the space on as close centers, horizontally and vertically, as required, without introducing too great a resistance to air flow. The water is distributed over the top layer by means of spray nozzles, troughs, splash heads, or through evenly spaced nozzles located in the floor of an overhead open-type water distribution basin, and drops from piece to piece of the wood filling as it progresses downward. As the air moves upward or across the wood filling, the latter presents a large wetted surface, repeatedly breaks up the falling drops of water, and continuously provides new drop surfaces whose integrated areas are several times that of the wood-fill area. The efficiency of a mechanical draft tower is improved by increasing the amount of filling, height, area, or air quantity. Increasing the height increases the length of time the air is in contact with the water, without affecting seriously the fan power required, but increases the pumping power. Increasing the area while maintaining constant fan power increases the air quantity somewhat and, because of lowered velocity, increases the time Fig. 8. Counterflow Induced Draft Cooling Tower They require less space and less piping than atmospheric deck towers, and the pumping head varies from 11 to 26 feet, depending upon the design. Overall plant economy, due to colder water temperature, usually more than onsets the additional operating expense and initial cost as compared with those of atmospheric towers. The counterflow (conventional) type of induced draft tower has the fan located at the top, Fig. 8, to provide vertical air movement across the ruling. Air is discharged upward at a high velocity to prevent recirculat'n. Another type, for small requirements, has the induced draft fan ln 0ne nd (see Fig. 9) to provide horizontal flow. Another induced draft tower, developed for the purpose of obtaining compactness, larger capacity, increased flexibility and improved perormance, is the crossflow type. This type of tower employs multiple os centered along the top, each fan drawing air through two cells paired fitwf sPc^'on chamber which is partitioned midway beneath the fans and ted with drift eliminators that turn the air upward toward the fan outlet, ms tower obtains a horizontal air movement as water falls in a cascade 788 CHAPTER 35 1954 Guide of small drops over the filling and across the air stream with less resistance to air flow. The air travel is longer than with the conventional design. Air velocities through mechanical draft towers vary from 250 to 400 fpm over the gross area of the structure. The air requirements are approxi mately 300 to 400 cfm of air per ton of mechanical refrigeration, and about 100 to 150 cfm of air per gallon of water passing through the tower. Cool ing tower calculations are based upon the fact that mechanical refrigera tion requires approximately 30 gallon-deg of cooling water per minute per ton of refrigeration. In atmospheric cooling towers, if 5 gpm were circulated, the water-cooling range would be 6 deg; with mechanical draft towers, 3 or 4 gpm are usually circulated for a desired water-cooling range of 10 or 7 F. Some designs of mechanical draft towers are limited to 6 oi 7 gpm per sq ft because of blanketing effect, while the capacity of the most efficient types ranges up to 9 or 10 gpm. When an inside cooling tower is required, some adaptation of a spray filled or wood filled induced draft tower is often used, and occasionally an Fig. 9. Small Horizontal Induced Draft Cooling Toweb fob 3 to 50-ton Refrigerating Units air washer is converted to this service. In this type of application pre cautions must be taken to prevent the discharged air from short circuiting to the intake. . MECHANICS OF ATMOSPHERIC WATER-COOLING The heat exchange in atmospheric water-cooling equipment is accom plished partially by a transfer of sensible heat which raises the wet-bulb temperature of the moving air; but- most of the cooling is due to an exchange of latent heat resulting from the evaporation of a small part of the water. If all of the water were cooled by evaporation, the rate of evaporation would be approximately one percent for each 10 deg of cooling. In prac tice, the loss of circulating water by evaporation will approximate 1 Per.` cent for 12 to 14 deg of actual cooling due to the additional amount of cooling by sensible heat transfer, and the rate of evaporation will vary from about 0.64 percent of the water circulated in the winter to 0.88 percent in the summer for a water-cooling range of 10 deg. .. The lowest temperature to which water may be cooled in atmospheric Spray Apparatus 789. cooling equipment is the temperature of adiabatic saturation, which is at the wet-bulb temperature of the air. Performance is measured in terms of approach (5 to 10 F deg, with 7 F deg average) of the cooled water to the wet-bulb temperature of the ambient air when cooling the water through some desired range. The water-cooling range in some installations will vary from 10 to 12 F deg when a spray pond is used, and from 5 to 17 F deg (with 10 F deg average) for a mechanical draft cooling tower. Heat absorption by the moving air in an atmospheric water-cooling tower continues as long as the wet-bulb temperature of the air is lower than the temperature of the water. The rate of heat transfer depends upon: (1) the area of water in contact with the air; (2) the relative velocity of the air and water during contact; (3) the difference between the wet-bulb temperature of the air and the initial temperature of the water; and (4) the time of contact of the air with the water. The rate of heat dissipation is also influenced by many other lesser factors8 which further complicate the cooling tower design. Ultimate selection of water-cooling equipment . for any specified service depends on overall economic considerations estab lished from correlated performance data. As the enthalpy of the moving air increases, its wet-bulb temperature rises (see Chapter 3). Since it is impracticable to allow the air to be in contact with the water for a long enough time to permit the wet-bulb temperature of the moving air and the temperature of the water to reach equilibrium, atmospheric water cooling equipment aims to circulate only enough air to cool the water to the desired temperature with least expenditure of power. DESIGN CONDITIONS FOR WATER-COOLING The maximum wet-bulb (design) temperature at which the total quan tity of circulating water must be cooled through a specified range by water cooling equipment is never selected as the highest wet-bulb temperature ever known to have occurred for some locality, nor the average wet-bulb temperature over any period of time. The maximum basis would require cooling equipment several times larger than normal capacity, and the average basis would result, for a large part of the time, in higher condenser temperatures than those for which the plant was designed. Accepted design practice for water-cooling towers, evaporative con densers, and spray ponds, is to use the maximum hourly outdoor dry-bulb temperature which will be exceeded no more than 2J percent of the time for the months of June to September; also, to use the maximum hourly wet-bulb temperature which will be exceeded no more than 5 percent of the total hours for the same period. Tabulation of these data has not been completed. The limited portion of such data as are available is given in Table 2, Chapter 13 for airport weather stations; for other locali ties design dry-bulb and wet-bulb temperatures in use locally are tabulated as a guide to design temperatures. More complete summer weather data, statistics, charts, maps, and' technical analysis have been prepared by Albright.4 Equipment for steam turbine condensers and internal combustion en gines, is usually based upon somewhat lower design temperatures if peak loads occur at night or during winter months when outdoor temperatures are lower. .Knowing the hot water temperature and the wet-bulb temperature for nich the equipment must be designed, the cold water temperature must e chosen to place the requirement within the effectiveness range of the 790 CHAPTER 35 1954 Guide type of atmospheric water cooling apparatus to be used. This effective ness is expressed as the percentage ratio of the actual cooling'effect to the maximum possible cooling effect. Since the wet-bulb temperature of the entering air is the equilibrium temperature to which the water could be ' cooled, the effectiveness of water cooling apparatus can be indicated thus: Ei = -----(-h-o--t--w--a--te--r--te--m--p--e-r-a-t-u--re--------c-o--ld---w--a-t-e-r--t-e-m---p-e--ra--t-u-r-e-)---X-;-1-0--0- -- hot water temperature -- wet-bulb temperature of entering air where . (, 2), Ei = water cooling effectiveness, percent. Magnitudes of this effectiveness ratio will vary through wide limits in accordance with construction and conditions of operation. Values indica tive of the commercial range of the effectiveness ratio are given in Table 3, although unusual designs may operate outside these ranges. Example t: A mechanical refrigeration installation requires 3 gpm of cooling water, per ton of refrigeration, with the hot-water temperature at 95 F and the coldwater at 84 F, with a design wet-bulb temperature of 78 F. Find the water-cooling effectiveness of a mechanical draft tower for the above conditions. Solution: Substituting known conditions in Equation 2, 95 - 84 ,N Water-cooling effectiveness = ---------- X 100 = 64.7 percent (typical). ' 95 -- 78 From a consideration of the factors which include the water-cooling range and the design wet-bulb temperature of the ambient air, the quan tity of water required can be calculated from the amount of heat to be rejected. The average quantities of heat to be removed, from various types of mechanical equipment that require cooling are listed in Table 4. WATER-COOLING TOWER DESIGN Because of the many variables' in water-cooling tower calculations and performance, it is difficult to provide simple handbook equations and tables whereby an engineer can readily select the type and size of unit for a definite requirement. Each manufacturer has a semi-confidential method of sizing a tower, based largely upon research and actual performance correlated with definite requirements; selection of water-cooling equipment for any specified service must ultimately depend upon overall considera tions established from reliable design and performance data. Some of the variables encountered in water-cooling tower work are: continuously changing air and water temperatures throughout the struc ture; varying moisture content, pressure, and volume of the moving air; caprice of the weather, ambient air changes in temperature, humidity wind velocity and direction, and the amount of sunshine. Other less important physical properties of the air and water affecting tower per formance are: density, specific heat, conductivity, viscosity, vapor pressure, surface tension, latent heat, coefficient of expansion, vapor diffusivity emissivity, and molecular weight. The air velocity, overall and in dif ferent parts of the tower, and also the type of air movement provided by natural draft, forced draft, induced draft, counterflow, or crossflow desigu have an important effect on heat transfer. Different features of construc tion will produce dissimilar velocities of water, and will affect its distribu tion and diffusion as well as the size of drops, jets, sprays, and sheets. The pressure and elevation of the water supply system, as well as the adsorption. Spray Apparatus Table 3. Effectiveness of Water Cooung Equipment 791 Cooling Equipment Spray Ponds..................................... Spray Filled Atmospheric Towers Atmospheric Deck Towers............. Mechanical Draft Towers.............. Water Cooling Effectiveness--Percent Minimum 30 40 50 50 Typical 40 to 50 45 to 55 50 to 60 55 to 75 Maximum 60 60 90 93 tarnibduitniotenr.facial surface tension of the wetted tower areas also affect dis Dissolved gases and other impurities in the water influence the water cooling process. Additional cooling tower variables affecting its perform ance include: location (ground, roof, nearby obstructions, wind orienta tion), dimensions, relative proportions (contour) of tower structure, ma terials, type and arrangement of interior surfaces; the louver and drifteliminator designs as they facilitate the air flow to and from the tower; temperature of the structure at different points as influenced by the external and internal conditions, Other cooling tower factors to be considered are: loss of water by entrainment (drift loss), design and location of water collecting basin, and surface evaporation therefrom; also the noise generated by the air, water, fan, and structure vibration. 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 similar to those encountered in the processes of diffusion in absorption and extraction equipment.6'6 Details of the application of the process to water-cooling tower perform ance have been published by various authorities,7 -8 '9 '10 '12 and those interested in the derivation of the various equations should refer to these references, as listed at the end of this chapter. The approach in each case is based on a heat balance in which the total heat given up by the water equals the total heat absorbed by the air. These derivations are also based on certain assumptions, viz: that the specific heat of water is unity at the temperatures encountered; that there is no loss in weight of the Table 4. Heat Absorbed bt Cooling Wateb Mechanical Equipment Btu per Min per Ton p""geratin Compressor.......... SteameTatlKn' A*?sorPtion System................... SteaS TU/llne CoDdeQser ...... ..... Diesel p>et Af:^r'gerating Condenser.... Four^g!neoJacket & L"be Oil: Pel!,. cyc|e> Supercharged....................... 7Vn ' y(;le' j)n supercharged............. Tvr0'pJc!e' h)rank-case Compressor............ . Two-`Cyc f' p"mp Scavenging, Large Unit. ^"rai Gas EnrineSCaVeDgmB' ^ Speed Four-cycle.. K ' two-cycle. . ................................... ' ----------- 250 550 550 = Btu per Lb of Steam 1000 1100 -- "* . Btu per BHP-HB -- -- -- 2600 3000 2000 2500 2200 4500 4000 792 CHAPTER 35 1954 Guide circulating water as a result of evaporation; that the water suspended in the tower is surrounded by a film of air which is saturated with'water vapor and at the temperature of the water surrounded; and that the basic theory of cooling tower operation proposed by Lewis13 and developed by Merkel14 is applicable. This theory refers to the fact that the numerical value of the coefficient of sensible heat transfer, when divided by the numerical value of the coefficient of diffusion, equals the specific heat (at constant pressure) of air. . The reader should observe that this relationship refers to the numerical values of three distinct constants, the units for each being different. The above relationship makes it possible to simplify the heat transfer equation by combining the two driving forces into one potential represented as the difference between the enthalpy of the air film (at water temperature) surrounding the water, and the enthalpy of the main air stream. conditions 1 WATER L. FLOW LB PER HR 'f- ACTIVE TOWER VOLUME V I AIR FLOW 1 Gx LB PER HR CONDITIONS 2 Fig. 10. Operations in a Typical Water Cooling Tower Tower Performance Factor The operations taking place in a typical water-cooling tower are shown in Fig. 10. If the reduction in water flow rate, due to evaporation within the volume, is neglected, and the usual concepts of heat flow and mass heat transfer are applied, the equations typifying cooling tower operation are: TM . [' -- G J2 h' -K (3) and KaV = r1 de J2L h" - K (4) where a = overall average wetted area (surface of water drops plus wetted tower sur face), square feet per cubic foot of active tower volume. G = weight rate of flow of air, pounds of dry air per hour. h = enthalpy, Btu per pound of dry air. Spray Apparatus 793 ha = enthalpy of air-vapor mixture, Btu per pound of dry air. h' = enthalpy of saturated air-vapor mixture at water temperature, Btu per pound of dry air. . . K = overall energy unit conductance, Btu per (hour) (square foot overall average wetted area) (Btu enthalpy difference per pound of dry air). L -- water rate, pounds per hour. , 8 = temperature of water in tower, Fahrenheit. 0i = temperature of inlet water, Fahrenheit. 0j = temperature of outlet water, Fahrenheit. V = active tower volume, cubic feet. '1 Either term or ^9^ may called the Tower Performance Factor Cr Lt ,' or Number of Tower Units (NTU). . Fig. WATER TEMPERATURE " FAHRENHEIT 11. Temperature-Enthalpy Diagram for Air-Water Showing Operating Lines for Example 2 Vapor Mixture These equations indicate that the rate of heat transfer from the water to the air depends primarily upon the enthalpy of the air, the latter being dependent only on the wet-bulb temperature of the air. This explains the common observation that cooling tower performance is independent of inlet dry-bulb air temperature, and that adiabatic conditions exist. uncgiauuu oi mquauons 6 ana 4 must be performed by mechanical or graphical means, because direct mathematical integration would be accurate only within narrow temperature limits. The temperature en thalpy diagram in Fig. 11 represents the conditions for either of the above equations. The water is cooled from the temperature 81 to 02, and the enthalpy of the air film surrounding it follows the saturation line A". Air enters the tower at a wet-bulb temperature of ti, and an enthalpy of -hi. It is heated to an outlet wet-bulb temperature of t[, with an enthalpy of hi. Since the heat rejected by the water equals the heat absorbed by tne air, the heat absorbed per pound of air is a function of the pounds of water per pound of air going through the tower, and the slope of the air operating line is the L/G ratio. 794 CHAPTER 35 1954 Guide Example 2: It is desired to cool 150,000 lb of water per hour (about 100 tons of mechanical refrigeration) from 110 to 84 F with 125,000 lb of dry air per hour, with a design wet-bulb air temperature of 75 F. These conditions could prevail with a steam-turbine driven centrifugal refrigeration compressor. Determine the Tower Perjormance Factor; show in tabular form the successive 6teps for this mechanical integration by selecting two-degree intervals of the water-temperature range. Solution: The accompanying Table 5 shows the sequence of mechanical integration for the given water and air temperatures. The first column shows the water temper ature 9 in increments of two degrees (A0 -- 2 F deg). Column 2 gives the enthalpies of the saturated air-vapor mixture at the water temperature, Btu per pound of dry air. The enthalpy of air, h* in column 3, has an original value of 38.61 Btu per lb corresponding to the 75 F entering wet-bulb temperature'of the ambient air; this value of A* increases in equal increments of 1.2 ^gratio^ Btu per F deg, hence, Ah = A9 X i = 2 X " 2.4. The potential for mass heat transfer is (h* -- A) asCsrhown in c1o2lu0m,wn(/4-i;uthis is frequently called the tower driving force po tential. The values in column 5 for each increment are determined by dividing 2.4 Btu per F deg by the average value of (h* -- hn); and column 6 is calculated in a similar manner, except that the increments are two degrees instead of 2.4 Btu. Mechanical Integration Tower Performance Factor. Table 5. Sequence of l 0Wateb Temp 2 Enthalpt Op Film A' a Enthalpy op Air . A,, Enthal.pt (j* -.)Difference 5 AA (A' - A.) (avg.) (A' - A.) (avg.) 84 86 88 90 92 94 96 98 100 102 104 106 108 110 48.22 50.66 53.23 55.93 58.78 61.77 64.92 68.23 71.73 75.42 79.31 83.42 87.76 92.34 38.61 41.01 43.41 45.81 48.21 50.61 53.01 55.41 57.81 60.21 62.61 65.01 67.41 69.81 9.61 9.65 9.82 10.12 10.57 11.16 11.91 12.82 13.92 15.21 16.70 18.41 20.35 22.53 0.249 0.247 0.241 0.232 0.221 0.208 0.194 0.180 0.165 0.150 0.137 0.124 0.112 0.208 0.206 0.201 0.194 0.184 0.173 0.162 0.150 0.137 0.125 0.114 0.103 0.093 Tower Performance Factor -- 2.460 or 2.050 Hence, the mechanical integration for the above conditions gives two results: ------ =- 2.46, Tower Performance Factor G h* -- An and KaV do - = 2.05, Tower Performance Factor h h" - K The results obtained in Example 2 are designated as the Tower Per formance Factor (TPF) or the Number of Tower Units (NTU); these figures represent correlated values that are directly proportional to the performance being considered. Similar calculations could be made for other quantities and temperatures of air and water. It should be noted that this factor is not related to the equipment doing the cooling, that any numerical value may represent an infinite number of possible performance conditions, that any cooling tower arrangement may give almost any performance under certain conditions. Also the mechanical integration Spray Apparatus 795 procedure used above applies only, to counterflow apparatus. However, the same principles may be applied to crossflow atmospheric water-cooling towers, although the method is more involved.,... The basic mathematical theory for water-cooling towers is now well established and recognized, but each manufacturer relies upon experimental results and practical experience with his own tower designs to establish a system for rating each unit that he builds. The problem of cooling tower design or selection is based on a knowledge of the characteristics of the equipment being considered. The Tower Performance Factor is a variable which is a function of the design; it also varies with the water loading and air velocity. Experimental data indicate that it varies with the heat load, although this variation may be due to deviations from the theoretical calculations which become more pronounced at the higher temperatures. The reference literature contains Tower Performance Factors which have been reported by various investigators, but the reader should be warned that the use of such factors, without a full understanding of the source, may lead to erroneous results. SELECTION OF WATER-COOLING TOWERS The correct type and size of water-cooling equipment for a given service cannot be determined intelligently without considering the characteristics of the various types, together with the many correlated requirement factors. Very few installations are exactly alike in details of requirements, hence, conditions affecting performance and operation of the several types of water-cooling equipment vary widely because of the many diversified applications and wide-spread geographical locations. Before the characteristics of a specific water-cooling apparatus can be judged desirable or undesirable for a given heat load and wet-bulb tem perature, a survey should consider the importance of each of the following items: first cost including all necessary auxiliaries, area, height, weight, effect of wind velocity and direction, rigidity of structure to withstand high winds, safety, conformity to building codes, drift nuisance, make-up water requirements and cost of chemical treatment if needed, total power for pumping (plus fan operation in the case of mechanical draft), maintenance, available locations (with due thought to possible future expansion, wind restrictions, space cost, proximity and accessibility, etc.), appearance, the equipment's operating flexibility for the most economical conformance to varying loads or seasonal changes, and other considerations occurring with regard to a specific application. For a definite heat-load dissipation, the type and size of a water-cooling tower is primarily affected by the following conditions: 1. Gallons per minute of cooling water. 2. Geographical location of the tower installation. 3. Wet-bulb design temperature of ambient air (see Table 2, Chapter 13). 4. Temperature of the hot water entering the tower at normal rating. 5. Temperature of the cold water leaving the tower at normal rating. 6. Ground, roof, or sub-structure installation. 7. Area available for cooling tower. 8. Proximity to other structures. 9. Surface of water exposed to each unit quantity of air. 10. Time of contact of the air with the water; this depends upon height (or length) of tower, and upon the relative velocity of air and water. 796 CHAPTER 35 1954 Guide The selection of a proper water-cooling range depends upon : (1) type of service--refrigeration, internal-combustion engine, or steam condenser; (2) wet-bulb air temperature at which the equipment must operate; and (3) type of condenser or heat exchanger employed. , Because the design of an entire plant is usually affected by the quantity and temperature of; the cooling water supply, plants should be designed for cooling water conditions which can.be most efficiently attained. The first consideration is usually the limiting temperature of the plant. For example/ if an ammonia compressor refrigerating plant is to be designed for 185 psig head pressure as a normal maximum, the limiting temperature of the ammonia in the condenser is 96 F. Should the ammonia tempera ture go above this figure, the head pressure will exceed 185 psig and the power consumption increase. To obtain this head pressure, the tempera ture of the circulating water leaving the condenser must always be less Table 6. Condenser Design Data Gas Desired Pressure in Condenses - Gas Temperature in Condenser, Fahrenheit Leaving Hot-Water Temperature, Fahrenheit Best Average Condenser Condenser Design Design 28 in. vacuum 101.2 27 in. vacuum 115.1 26 in. vacuum 125.4 185 psi* . 96.0 Carbon dioxide................. 1030 psig* 102 psig* 86.0 100.0 117 psig* 100.0 126 psig* 105.0 136 psig* 110.0 97 93 no 105 120 114 92 88 83 80 96 92 96 93 100 97 104 101 * Head pressure. than 96 F by an amount depending upon the size and design of the con denser, the quantity of water being circulated, and the refrigerating tonnage being produced. A condenser having a large surface per ton of refrigera tion may be designed to operate satisfactorily with the leaving hot-water temperature within 3 or 4 deg of the ammonia temperature corresponding to the head pressure, while a small condenser may require a 10 deg dif ference. . Table 6 lists several gases with data for the temperatures and pressures for which commercial condensers are designed. Careful evaluation of costs of water and electrical power should be made before deciding to use city water for jacket water and condensers. Economy of operation gen erally indicates the use of either a water-cooling tower or an evaporative condenser for most refrigeration installations of five tons or more capacityRefer to Chapter 37, for information on Evaporative Condensers. In ternal-combustion engines have limiting hot water temperatures of 140 to 180 F for closed systems, and liO to 130 F for open systems, depending upon the quality of the cooling water. The cooling of such fluids as milk or wort has variable requirements, and is usually accomplished in counter flow heat-exchangers in which the leaving circulating water is at a much higher temperature than is the leaving fluid. Spray Apparatus 797 OPERATION AND MAINTENANCE Water Treatment. The amount of make-up water required by a cooling tower depends upon evaporation loss, drift loss, and blow-down. Evapora tion losses average 0.80 percent of the water circulated for each 10 F deg range. Drift loss is. the water carried out of the tower by the air currents in the form of droplets or mist. In properly designed induced draft towers this loss normally approximates one-tenth of one percent, and most cooling tower manufacturers will guarantee a drift loss not to exceed twotenths of one percent. The amount of blow-down water wasted depends upon the hardness of the circulating water, type of water softening used and the amount of drift loss. Blow-down is normally controlled to main tain the concentration of soluble and scale-forming solids below the point where the formation of scale would occur or would be caused by corrosion. Algae formations will plug nozzles and prevent proper distribution of the water over the tower filling. This growth may also collect on equip ment served by the cooling tower, and thereby reduce the heat transfer rate. Algae should be held at a minimum or eliminated by use of bromine, chlorine, chlorinated lime, copper sulfate, or various blends of chlorophenates (see Chapter 43). Although some scale-forming materials are found in practically all water, those which cause trouble in water-cooling systems are normally calcium and magnesium carbonates. Scale formation in equipment served also reduces heat transfer rates. Scale can be reduced materially or prevented by softening the make-up water with lime and soda ash, zeolite, or sulfuric acid, or by use of small amounts of sodium hexametaphosphate. Water softening or treatment requires close regulation and control by a competent chemist. Too high a concentration of soluble solids in cooling tower water may raise the temperature of the water leaving the tower, and may cause sludge deposits or corrosion in the system. Concentration of solids is normally controlled by either blowing down or by a continuous overflow to the sewer. Refer also to Chapter 43. Delignification. The presence of sodium carbonate in the circulating water results in delignification of any wood with which water comes in contact. This chemical dissolves lignin which binds the wood fibers to gether and leaves the wood surface in a white fibrous condition. Prolonged exposure reduces the structural strength of the wood. Delignification first appears on parts of the tower that are alternately wet and dry, since evaporation at such points rapidly increases the concentration of dissolved solids. The presence of sodium carbonate in harmful amounts is generally indicated by a high pH of 9 to 11. The effect of the sodium carbonate may be neutralized by the use of sulfuric acid. It is desirable to have the pH value of the water at 7 to 7.5 (7.2 pH value is neutral for redwood). Two-speed Motors. For readily adapting tower performance to tempo rary or seasonal decreases in heat load, and especially for winter operation, the use of two-speed motors (for fan drives) is recommended. The chief advantage is that when operated at half-speed, fans require only about 15 percent of the power used at full speed. Particularly in multi-fan towers, the ready flexibility provided by two-speed motors results in considerable . savings, even though load reductions may sometimes call for only one or a few fans to be operated at half speed. Cold-weather Operation. Extremely cold water normally does not in- 798 CHAPTER 35 1954 Guide crease performance to any great extent, but increases operating hazards considerably. Water-cooling towers operated in sub-freezing weather are subject to ice formation on the louvers and the outer portion of the filling. To prevent icing in cold-weather operation, the cold raw water (tower circulating water) temperature should be maintained as high as practicable, taking into consideration the effect upon the economy of the equipment served. One or more of the following procedures are recommended for induced draft towers: (a) run two-speed motors on low speed, or shut off some of the fans; (b) shut down some cells completely and put all of the water over the remaining cells; (c) reduce water flow to the tower and shut off some of the cells; (d) by-pass the cooling tower with part of the water and shut off some of the fans or cells of the tower. If ice should form on the louvers and filling, one of the following methods of removal can be used: (a) reversing (for not more than TO minutes) the rotation of the motor driving the fan and thus blowing the warm air out through the louvers; (b) shutting down fans on some sections tem porarily, but not the water. When these cells have thawed out, use the same procedure on other cells. Where intermittent operation of a system is employed, water in outside basins may cause considerable damage due to freezing. To prevent this, such basins are drained when out of service and therefore in some small roof installations a tank large enough to hold all the water in the system may be installed inside the building. Maintenance. Well-maintained equipment provides the best operating results and the least overall maintenance cost. A regular schedule should be set up for the structural and mechanical upkeep of water-cooling towers. The life and continued utility of any cooling tower is directly dependent upon its inherent qualities, climatic environment, type of service, severity of operation, and general care and maintenance. REFERENCES , 1 Temperature of Water Available for Industrial Use in the United States, by W .1). Collins (U. S. Geological Survey, Water Supply Paper No. 520 F). ' 5 A.S.H.V.E. Research Paper--Design of Spray Cooling Ponds, by S. Hori, U. A. Patchett and L. M. K. Boelter (A.S.H.V.E. Journal Section, Heating, Piping and Air Conditioning, October, 1942, p. 624). 8 Cooling Tower Performance Studies, by L. M. K. Boelter (A.S.H.V.E. Transac tioInSsu, mVmole. r45W, e19a3th9e, rp.D6a1t5a).; Statistics, Charts, Maps, and Analysis, by J. C. Al bright, 1939. (The Marley Company, Inc., 1944). 8 Principles of Chemical Engineering, by W. H. Walker, W. K. Lewis, W. H. Mc Adams and E. R. Gilliland (McGraw-Hill Co., 1937, p. 480). 5 Absorption and Extraction, by T. K. Sherwood (McGraw-Hill Co., 1937, p. 91). 7 Heat Transmission, by W. H. McAdams (McGraw-Hill Co., 1933, p. 157). 8 Performance Characteristics of a Mechanically Induced Draft, Counterflow, Packed Cooling Tower, by A. L. London, W. E. Mason and L. M. K. Boelter (A .S.M.E. Transactions, January, 1940, Vol. 62, p. 41). 8 Determination of Unit Conductances for Heat and Mass Transfer by the Tran sient Method, by A. L. London, H. B. Nottage and L. M. K. Boelter (Industrial and 'EnglinGerearpinhgicCahl eMmeisthtroyd, Aopf rDil,e1te94rm1,iVnionlg. 3N3,upm.b4e6r7)T. ransfer Units, by T. Baker (In dusIItrPiaelrfaonrdmEanncgeineaenrdingSCelheecmtioisntryo,f AMuegcuhsat,n1ic93a5l-,DVroalf.t2C7,opo.li9n7g7)T. owers, by Joseph Lichtenstein (A.S.M.E. Transactions, October, 1943, Vol. 65, No. 7, p. 779). 17 Performance of Small Mechanical Draft Cooling Towers, by W. M. Simpson and T. K. Sherwood (Refrigerating Engineering, December, 1946, p. 535). 18 The Evaporation of a Liquid into a Gas, by W. K. Lewis (A.S.M.E. Transac tion14s,VVerodl.us4t4u,n1g9s22K, ipih. l3u2n5g)., by H. Merkel (Forschungsarbeiten, No. 275, 1925). CHAPTER 36 AIR HEATING AND COOLING COILS Uses for Coils, Coil Construction and Arrangement, Steam Coils, Water Coils, Direct-Expansion Coils, Flow Arrangement, Applications, Coil Selection, Heat Transfer and Air Flow Resistance, Perfonnance of Heating and Dry Cooling Coils, Overall Coefficient of Heat Transfer, Perform ance of Dehumidifying Coils, External Film Coefficient, Internal Film Coefficient, Determining Size of Cooling Coil COILS described in this chapter are used for heating or cooling an air stream under forced convection. Surface coil equipment may be made up of a number of banks assembled in the field, or the entire assembly may be factory constructed. The applications of each type of coil are limited to the field within which it is rated. Other limitations are imposed by code regulations, by proper choice of materials for the fluids used and the condition of the air handled, or by an economic analysis of the possible alternates on each installation. USES FOR COILS For heating service, coils are used as tempering coils, preheaters, reheaters Or booster heaters. 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 refriger ating system. Coils are used for air cooling with or without accompanying dehumidi fication. Examples of cooling applications without dehumidification are precooling coils using well water or other relatively high temperature water to reduce the load on the refrigerating machinery, or water cooled coils re moving sensible heat in connection with chemical moisture-absorption apparatus. By proper coil selection it is possible to handle both sensible cooling and dehumidification together. The assembly usually includes air cleaning means to protect the coil from accumulation of dirt, and to keep dust and foreign matter out of the conditioned space. Although cooling and dehumidification are the usual functions, cooling coils are sometimes purposely wetted to aid in air cleaning and odor absorption. The usual cooling media used in surface coils are cold water or Group I (ASA Classification) refrigerants, but others are used in special cases. Brines are seldom required for the range of applications covered by this chapter, although there are cases where low entering air temperatures with large latent heat loads require a refrigerant temperature so low that use of water becomes impracticable. Sometimes, also, brine from an industrial system already installed is the only convenient source of refrigeration. Tor combined cooling and dehumidifying, surface coils present an alter nate to spray dehumidifiers. For many applications it is possible, by Pfoper selection of apparatus, choice of air velocities, refrigerant tempera- 799 800 CHAPTER 36 1954 Guide tures, etc., to perform the same duty with either. In a few cases both sprays and coils are used.. The coils may then be installed within the spray chamber, either in series with the sprays or below them. In making the selection between spray and surface dehumidifiers, certain advantages of each should be considered. The fact that a spray dehumidifier is usually designed to deliver nearly saturated air, tends to simplify the control prob lem. In this case the dry-bulb temperature is also the dew-point, and- hence, a dew-point control can be arranged by using a simple duct thermo stat. Spray dehumidifiers have an advantage over unwetted coils of ob taining some air cleaning and odor absorption. On the other' hand, coils make possible a closed and balanced cooling water circuit, obviating the unbalanced pumping head, the complication of water level control, and danger from possible floods incidental to multiple spray dehumidifiers, 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 the one season and hot water in the other, with consequent saving in apparatus and piping. Another advantage is that where the surface coil system can be used with direct expansion of refrig erant, it is comparatively low in initial and operating costs. The safety of the occupant must be kept in mind in comfort conditioning applications. Some localities have refrigeration codes which restrict the use of directexpansion coils in the air stream, and hence, local codes should be consulted by the engineer before a System employing direct expansion methods is designed. The choice between spray dehumidifiers and coils depends upon the necessities and the economic aspects of each case, and no general rule can be given. There are many installations in which either may be used. COIL CONSTRUCTION AND ARRANGEMENT Coils are basically of two types, those consisting of plain tubes or pipe, and those having extended surfaces. The former are little used for the applications covered by this chapter, but are often employed where condi tions cause frost accumulation, and for cooling within spray dehumidifiers. The heat transmission from air passing over a tube to a fluid flowing within it is impeded by three resistances. The first is that from the air to the surface of the tube and is usually called the outside surface resistance or air-film resistance. The second is the resistance to the conduction of heat through the metal itself. Finally there is another surface or film resistance to the flow of heat between the inside surface of the metal and the fluid in the. tube. For the applications under consideration both the resistance of the metal wall to heat conduction, and the inside surface or film resistance are usually low as compared with the air-side surface resist ance. Economy in space, weight and cost makes it advantageous to de crease the external surface resistance, where it is proportionately large, to approach that of the tube wall, and that from the tube to refrigerant; This may be accomplished by increasing the external surface by means of fins. Sometimes water spray is applied to the same type surface as would have been used without it. The overall heat transfer is not necessarily 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 secondary. 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 arrangement is usually preferred because it obtains a somewhat higher heat Air Heating and Cooling Coils 801 transfer value. Numerous types of'fin arrangement are used, themost common of which are spiral; flat and flat-crinkled or corrugated; all as shown in Fig. 1. While 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 cominon: types, are in'use, the selection for a particular installation being based: on economic considerations, space re quirements and resistances of individual designs of coils. A most impor tant 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 order to , assure a continuing; 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 then are 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 finmay be knurled into a shallow groove on the'exterior of the; tube. The tube may be ex- Fbt continuous fins O O 4# 3 00 QO ` ` 'flat conugated fins ' O' O ; - ; - Oat square fins . ' Fig. 1. Types:op Fin Coil Arrangement , . panded after the fins are assembled, 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 coils, materials most generally used are copper and aluminum. Steel is occasionally used where sodium or calcium chloride brine is circu lated in the tubes. Aluminum fins on copper tubes are a common con struction. 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 copper fins and tubes, although aluminum 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 f, and 1 in. outside diameter, and with fins spaced three per inch up to eight per inch. The tube spacing generally varies from about to 2^ iri. 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 atten tion being paid to lint accumulation and, especially in dehumidifying, the consideration of frost accumulation. Steam Coils For proper performance of steam heating coils, condensate and air must he continuously eliminated and the steam must be evenly distributed to the individual tubes. This distribution' is usually accomplished by ihdi- CHAPTER 36 1954 Guide 802 vidual orifices in the tubes, by distributing plates and orifices ip the steam header, or by perforated internal steam-distributing pipes extending into the individual tubes. The latter arrangement has the advantage of dis tributing 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 fight heating loads, is also minimized. This is especially valuable for outside air pre heaters. WaTtheer Cpeoriflsormance of water coils, for heating or cooling, depends on the a;r frr)m ^e system and proper distribution of water. Air Air Heating and Cooling Coils 803 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 thermal expansion valve sys tems, 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 thermal expan sion valve system depends upon the thermal valve automatically feeding just as much liquid to the coils as is required to maintain the superheat at the coil suction outlet within predetermined limits, which vary from about 6 to 10 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. No auxiliary distributing devices are re quired. With the thermal valve system, there are two factors to consider. Fio. 2. Various Water Circuit Arrangements elimination is taken care of in the system piping as described in Chapter 22. 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 precooling coils using well water, where there may be consider able sand and other foreign matter in the water, provision for cleaning of individual tubes is of advantage. 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. DirCeoctil-sExfopranvsoiolantilCeorielsfrigerants present more complex problems of fluid distribution than do water, brine or steam. It is desirable that the coil Fig. 3. Direct-Expansion Coil with Flooded System Fig. 4. Direct-Expansion Coil with Thermal Valve System There must be, generally, more than one refrigerant feed through the coil per thermal valve to keep the pressure drop through the refrigerant circuit within practical limits, and to reduce the corresponding penalty in increased evaporating temperature. At the same time the coil must be so arranged that the required suction superheat can be attained with a minimum sacri fice in the performance of the coil as a whole; It is general practice to attain this superheat within the coil itself, and not by the use of external beat exchangers or other auxiliary devices. With thermal expansion valves it is advantageous to keep the pressure drop through the refrigerant feeds as low as possible. The feeds are laid . out to expose each to the same mean temperature difference so that it bandies the same refrigerating load. Here, a distributing means is imposed 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 jjpd gas mixture from the thermal valve is led tangentially into a chamber. The coil feed connections extend outward radially at the top of this chamber. In distributor B the refrigerant is discharged at a high velocity through a central jet against the end plate, forming a uniform 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 804 CHAPTER 36 1954 Guide the thermal valve and is discharged against the end plug in which the indi vidual liquid feeds are closely arranged.: These distributors 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 con nections 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 super heat 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 Air Heating and Cooling Coils ' gQ5 in steam heating coils, the temperature within the tubes being substantially uniform, fend the mean temperature difference the same whatever the direc tion of flow, relative to the air. Cross-flow is to be avoided in coils with volatile refrigerants, because of unequal loading of parallel circuits, and the danger of short circuiting of liquid refrigerant which disturbs proper functioning of the thermal expansion valve. ' Applications Heating coils in field assembled banks are used for a number of purposes as described in Chapter 30. They may be arranged with the air flow should be avoided, since it offers the disadvantage of unequal load on the two parallel circuits. ; Flow Arrangement . The relative directions of flow of the air outside the tubes and the medium' within them, influence the performance of the surface. There are threetypes of relative flow in common use. Fig. 8A shows parallel-flow in1 which the air and the medium in the tubes proceed through the coil in the same direction. Fig. 8B shows counter-flow in which the medium in the tubes proceeds in a direction opposite to the flow of air. Fig. 8C shows cross-flow in which the air and the medium in the tubes pass at right angles to each other. The counter-flow arrangement is almost universally used' in brine or water coils to take advantage of the highest possible mean temfi perature difference for given entering water and air temperatures. It is also commonly used, in coils fed with volatile refrigerant, to take advantage; of the higher air temperature for superheating the leaving gas. . In deep; coils, however, it is sometimes advantageous to use parallel flow from second: row to last row, and then to complete the circuit by passing through the first row to take advantage of the higher air temperature for superheating-' Complete evaporation and superheating of the refrigerant are essential to proper operation of the thermal expansion valve. . Cross-flow is common Fig. 6, Arrangement fob Face Control ' Fig. 7. Arrangement for Depth Control vertical or horizontal, although the latter is more common. For'steain heating, 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 avoid- lng air and water pockets, water heating 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.; . There are coils available having inner distributing tubes, and having the suPply and return headers cast in one piece. In this type of'coil the condensate that forms in the outer tube has resulted from steam.fed from the inner tube orifices! This condensation flowing back along the warm inner tube is prevented from freezing. A wide range of modulation at very lew temperatures without danger of freezing, is therefore obtained. As'an nnded precaution, with both steam and water coils, the outside air inlet 806 CHAPTER 36 1954 Guide 2 dampers are often closed automatically when the fan is stopped to avoid trouble caused by very cold outside air drifting in during ojj periods. A typical arrangement of cooling coils is shown in Fig. 9. Some means should be provided to filter all the entering air to keep dirt and foreign matter from accumulating on the coils. The assembly is provided with a drip-pan to catch the condensate during summer dehumidifying duty, and to collect the non-evaporated water from the humidifying sprays in winter. The drip connection should be made ample in size and liberally provided with cleanout fittings. It should not be exposed to freezing temperatures in winter if the apparatus is used on winter humidifying duty. Access doors should be provided for servicing filters, humidifying nozzles, and fail : bearings, and for cleaning the coils. When coils are used for dehumidifying, eliminators must be used beyond the coil to catch any water which may be , blown into the air stream. It is customary to include these eliminators, when the air velocity exceeds about 450 fpm. Where a. number of coil Air Heating and Cooling Coils 807 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, connec tions. (See Chapter 21.) '. COIL SELECTION In the selection of a coil it is necessary to consider several factoVs: 1. The duty required--heating, cooling, dehumidifying. 2. Temperature of entering air--dry-bulb only if there is no dehumidification; dry- and wet-bulb if moisture is to be removed. . 3. Available heating and cooling media. .. 4. Space and dimensional limitations. 5. Air quantity limitations. . . " . 6. Allowable resistances in air circuit and through tubes. Fio. 8. Flow of Media in Tubes in Relation to Air Flow sections are stacked one upon another, and where the velocities are low, so that eliminators need not be used, occasional trouble results when water splashes down from one coil to the next and blows out into the air stream. In such cases drip troughs as shown in Fig. 10 are used to collect this water and conduct it to the condensate pan. Sometimes finned surface coils on summer cooling and dehumidifying duty are provided with water sprays. These sprays are of two types. In the first type, a set of spray nozzles is arranged for intermittent cleaning. These sprays are not operative when the system is in use, and no recircu lating pump is provided. The second arrangement requires a collecting tank and a recirculating pump. The water is in circulation whenever the apparatus is in operation, and assists in keeping the coil clean and in absorb ing odors. Fig. 11 illustrates such an arrangement. Wherever air by passes are used around a coil on summer duty for control purposes, it is advantageous to direct only return air through the by-pass rather than a mixture of return and outside air. The casing should be arranged accord ingly. To maintain the air quantity handled by the fan reasonably con stant, and to assure the required design quantity of by-passed air when the by-pass damper is open, cooling coil banks are frequently furnished with both face and by-pass dampers as shown in Fig. 9. Fia. 9. Typical Arrangement of Cooling Coils in a Central System 7. Peculiarities of individual designs of coils. 8. Individual installation requirements, such, for example, as type of automatic Control to be used. The duties required may be determined from information in Chapters 9, 11, 12 and 13. There may, or may not, be a choice of cooling and heating Media, as well as temperatures available, depending upon whether the 'installation is new or is in combination with present sources of heating or cooling. Space limitations are dictated by the requirements of individual "fses. The air quantity is influenced by a number of considerations. The Mr quantity through heating coils is often made the same as that necessary to handle the summer cooling load. The air handled may be fixed by the Use of old ventilating ducts as the air distribution system for new air condi tioning apparatus, or may be dictated by requirements of satisfactory air distribution or ventilation. The resistance through the air circuit influx ences 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 expense ow> or it may be limited by the maximum fan peripheral velocity which Mquirement of quietness may permit. The friction through the water or 808 CHAPTER 36 ; 1954 Guide d brine circuit may be dictated by the head available fromi a given size of y pump and pump motor. As the fan and pump motor inputs represent a refrigerating load on cooling installations, it is economical to keep them low-.' Proper performance of a surface heating or cooling coil depends upon' correct choice of the original equipment, and upon certain other factors. The usual coil ratings are based on a uniform face velocity of air. If the air is brought in at odd angles, or if the fan is located so as to block part.of the air flow, the performance as given in the manufacturer's ratings cannot usually be obtained. To obtain rated performance it is necessary, that the air quantity be adjusted on the job to that used in determining the coil selection, and that it be kept at this value. The most common causes' of a reduction of air quantity are the fouling of the filters and collection,of dirt in the coils. These difficulties can be avoided by proper, design and Fig. 10. Coil Arranged with , Drip Trough Fig. 11. Recirculating Spray System for Cleaning Coils proper servicing. There are a number, of ways in which coils may be cleaned. A common method is to wash them off 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 accu mulated, it is sometimes necessary to remove the coils and wash off the accumulation with steam, compressed air and water, or hot water. The most satisfactory solution, however, is to keep the filters serviced, and thus make the cleaning of the coils unnecessary. ,. The proper selection of coils requires an understanding of the require-, ments of each case, and should be based on an economic analysis of the plant, design as a whole. No general rule can, therefore, be laid down for the selection of heating or cooling coils. It is possible, however, to point out the limits of usual practice and to indicate the influence of the variable?, involved in the coil selection. : i, Heating Coils Steam and hot water heating coils are usually rated within these limits: Air Face Velocity--200 to 1200 fpm, sometimes up to 1500 fpm. Steam Pressure--2 to 200 psig, sometimes up to 350 psig. ' Air Heating and Cooling Coils 809- Hot Water Temperature--lSO to 225 F. ., , .... / .. Water. Velocity--2 to6 fps. , ... Individual cases may deviate widely, but the tabulation given herewith will serve asm guide:to usual heating installation practice:; , Air Face Velocity ^-500 to 800 fpm face, 500 being'a common,figure: ` ' ' V, 150DFelifvoerrecdomApirleTteemhepaertiantgu.re---v.a. ries.. from',about 72.F fSf.yentilAtibn only, to about Steam Pressure--2 to 10 psig, 5 psigbeing^comrnpn;..... .. . " Hot,Water Temperature--150 to 225 F. i........... ; Water Velocity--? to 6 fps. , | r ' I.............. m,-, . Water Quantity--Based on about 20 deg'temperature drop through' a.hot-water coil. . ' 1 \. ; .......... -v, Air Resistance--The total resistance through heating, coils is .usually limited to from i to f in. of water gage for public buildings, to about PihV'for factories. The selection of heating cpils is relatively, simple-as it involves Sign-bulb temperatures and sensibleffieat only;- without the complication, of^ simul taneous latent heat loads; as in -cboling coilsi i For a given duty, entering airtemperature, and steam ;pressure; it is possible t6 select several arrange^ ments of the same design of coil depending upon the relative unpbrtahce of space, crosSTsectional.areaj.andiair-resistance. ; Cooling Coils ... .., . ... Cooling, and dehuniidifying 'coils'are usually rated within these limits : Entering Air Dry-Bulb--60 to 100 F: / i -, ,; . , Entering Air Wet-Bulb--50 to 80 F. . ... . ... - . Air Face Velocities--300 to 800 fpm (sometimes'as low as 200 and as high as-1200)'. ' Volatile Refrigerant'Temperatures-^-25 to'55 Fj at coil-suction outlet:1; ' .-, Water Temperatures4^40 to,65-F. i.-.-.' , i-.-f;-: a -- : Water Quantities--2 to ,6 gpm ,per ton,, or equivalent to ta' water temperature rise of from, 4 to,12.deg. .. ... ,. , ... .... ...... "... ., A : Water Velocity---2 to 6 fps. . .. -, The ratio of total to sensible heat removed varies in practice from 1.00 to about.1.65, t.e., sensible ,heat,is from 60 to 100 percent of total, depend ing on the application. ; (See Chapter 30.). Since required ratios may de mand wide-variations;in air velocities, refrigerant temperatures,;and Coil depth, general rules as to their values may be misleading.... On usual com fort installations air face velocities between .400 apd 600,fpm are frequent, 600 being a common valued , Refrigerant; temperatures .ordinanly vary between 40 and 50 F where cooling os accompanied , by dehumidification. 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 coqling, coil surface temper ature, the coil selection'is made on, the basis of dry-bulb,temperatures and sensible,heat transfer only, the same as .with,heating.cpils. It is possible also to choose various .arrangements of face area, depth, air velocity, etc., for. the same duty. . , Dehuniidifying Coils V : '' ' ' .' . ' The selection of. coils for combined;cooling,and dehumidifying duty is more involved than for heating or sensible cooling, and requires consideration.,of both dry- and wet-bulb air temperatures,. It is further compli cated by the fact that the proportional amount of dehumidification required 13 highly variable. The methods outlined in the section, Heat Transfer and Resistance, may, be used .to determine whether it im possible for a coil > perform the duty required. If entering and leaving air conditions are 810 CHAPTER 36 1954 Guide Table 1. Various Cooling Coil Arrangements Selection 1 Total cooling capacity, tons.--: 100 Sensible cooling capacity, tons... 69 Latent cooling capacity, tons.... 31 Ratio total to sensible heat...... 1.45 Air quantity, cfm. ----- ---- .. 47,800 478 Face "velocity, fpm.------------------ 325 0.11 Coil face area, sq ft------ ----------- 147 Coil rows deep___________ 4 Coil evaporator temp. F deg..... 45 2 100 69 31 1.45 41,700 417 423 0.27 99.0 6 45 3 100 69 31 1.45 37,100 371 500 0.51 74.2 8 45 4 100 69 31 1.45 46.800 468 600 0.37 78.1 4 38 arbitrarily specified, the corresponding duty sometimes cannot be obtained at all without the use of reheat. As with heating and sensible cooling coils, there are combinations of face areas, depth, air velocity and refrigerant temperatures which will give: the required performance. This is illustrated in Table 1. - ,, It is possible, as shown in Table 1, to perform approximately the same duty at a given refrigerant temperature with small face area and large thickness or vice versa. The large face area coil gives low air velocity and resistance, but high air quantities per ton. The coil of small face area and great depth requires small air quantities per ton of refrigeration, high resistance and high air velocities. As shown also in Table 1 the same sensi ble, latent and total cooling capacity may be obtained with various refriger ant temperatures by proper choice .of coil. This makes it possible to keep the evaporating temperature high enough to carry the load with a chosen size Of condensing unit. High evaporating temperatures with correspond ingly small compressor operating expense can be attained, but at the ex pense of coil surface, air quantity or both. The choice will be determined by the necessities of individual installations. For a given quantity and condition of entering air, the evaporating tem perature of a volatile refrigerant coil is determined by a balance between the condensing unit and the coil. The total, sensible and latent cooling capacity can then be determined from the coil rating information. If the condensing unit and cooling coil have been properly balanced for the re quired load and, due to miscalculated duct resistance or improper choice of fan speed, the air quantity is reduced, the total cooling capacity will also be reduced. The decrease generally affects the sensible capacity. This is also true when the air by-pass or volume control is used. It is necessary that not only the total capacity, but also that both sensible and latent cooling requirements be met. The installation of an excess of coil results in an increase in total capacity, but not in proportion to gain m latent heat capacity. On installations controlled from dry-bulb tempera ture, the operating time is shortened because of the added sensible cooling capacity. This results in less moisture pick-up and higher relative humid ity than calculated. If an oversize condensing unit is installed, the oppo site situation occurs. Generally, this is not a disadvantage, except that it results in a load from outside air greater than calculated, as well as in in creased power consumption. If oversize equipment is furnished, a balance should be made to assure that the ratio of total to sensible capacity is the same as in the estimated load. Sometimes, arbitrary air quantities are specified for ventilation or other Air Heating and Cooling Coils . 811 Table 2. Capacity Balances for Maximum and Minimum Load Conditions Conditions Required at peak load conditions........ Required at minimum load conditions______ Peak load equipment balance. - Same equipment balanced at minimum load rnnriifinns ,, Same equipment balanced at maximum load conditions with 40 Der cent bv-pass_.: . .... Same equipment balanced at minimum load conditions with 38,800 Btu per hour reheat Capacity in Tons Total 10.90 6.62 10.90 Sensible 7.90 3.36 7.90 Latent 3.00 3.26 3.00 9.85 6.58 3.26 8.38 5.05 3.33 6.62 3.36 3.26 ratio TotmSensible 1.38 1.98 1.38 1.66 1.98 reasons independent of the selection of the cooling coil. As, shown in Table 1, the coil selection can be altered to take care of various air quantities for the same duty. Where coil and condensing unit are selected for the peak load condition, and the sensible load.partially disappears due to fall of outside temperature or other cause, the condensing unit and coil will rebalance. This may ob tain more sensible and less latent capacity than required at the light load condition, with an increased relative humidity in the conditioned space. Such a condition is shown in Table 2. If approximately 40 percent of the total air is by-passed, the condition is improved as indicated. The situa tion may be entirely avoided by using reheat, where it is possible to handle any ratio of sensible and latent loads and maintain the design temperature and humidity.1 " Care should be taken to avoid freezing at light loads. In general, freez ing occurs when the coil surface temperature falls to 32 F. With usual coils for comfort installations, this does not occur unless the evaporating tem perature at the coil outlet is about 20 to 25 F. The exact value depends on the design of the coil and the amount of loading. Although it is not customary to choose coil and condensing units to balance at low tempera tures at peak loads, there is danger of this occurring when the load decreases. This is further aggravated if a by-pass is used so that less air is passed through the coil at light loads. It may be even worse if the control is arranged for decrease of inside temperature with fall of that outside. Freezing can be avoided by making the full load balance a high evaporating temperature, and checking the balance at the minimum load. Care should be exercised in the design of humidity control to minimize the cycling of the refrigerating compressor because of re-evaporation of moisture from the fins. It is sometimes necessary to by-pass air around a coil when the compressor is not operating. HEAT TRANSFER AND AIR FLOW RESISTANCE The transfer of heat between the heating or cooling medium and the air stream is influenced by several variables: 1- The temperature difference. *- The design and surface arrangement of the coil. " The velocity and character of the air stream. ' The velocity and character of the medium in the tubes. The driving force is usually taken as the logarithmic mean temperature difference for heating or cooling without dehumidification. For combined 4512 CHAPTER 36 1954 'Guide cooling and dehumidification, the logarithmic difference does not apply strictly, and such problems should be handled as described in a later section on Performance of Dehdmidifying, (Joils. With volatile refrigerants there is often an appreciable pressure drop and corresponding change in evaporat ing temperature through the refrigerant circuit. The problem is further complicated by the'fact that' the refrigerant is evaporating iii part; of ttie circuit, and superheating in the.remainder.' In'spite pf .'this,;:heat trahsfer and ratings for coils using volatile refrigerants are usually leased on' a refrigerant temperature corresponding to the average pressure in'the eoil. The design and surface arrangement of the coil include such items as materials, type, thickness, height and spacing of-the fins, and the ratio of this surface to that of the tube, the use of the staggered or in-line'tube arrangement, and provisions to increase the air, turbulence such as the use `of corrugated as against'flat fins. Staggered tubesiincrease the total hekt 'transfer, as against the in-line arrangement, and corrugated fibs may be more effective than flat. This design and surface arrangement has a large ,effect on the air film heat transfer resistance. ; ' ' ['' - The, velocity of the air usually considered is the: coif face velocity. This .bears, a.varied relation tothe actual velocity over the; surface,: depending upon the individual coil design. ' As long, as a fixed design of coil is under con sideration face velocities may be used, but;they may be unsatisfactory.in comparing different designs, as it,is the actual surface velocity lhal is)signifi cant. The air volume is often based on standard air at 70 F and a baro metric pressure of 29.92 in. Hg,. The use of; air volume .in cdil rating information may be misleading. The significant value is mass ,velpcity.in_ pounds per (minute) (square foot of face area) and not .cubic feet per minute, because for a!;'fixed::yOliime the corresponding weight may vary widely, ''depending upon the tcmperature and barometric pressure. ` " j h.At the same mass air velocity, varying performance .can be obtained .depending upon the turbulence .of the air flow into the' coil, and upon the . uniformity of -distribution of air over the coil face. The latter is. very im- portantin: obtaining,reliable test ratings, and in realizing rated performance :in practical, installations. The resistance through the Lcoils will, assist iii . distributing: the air: properly, but where the. inlet, duct connections are brought in at sharp angles to the coil face, the effectis frequently bad and there may even be reverse air currents through the coils. This reduces the capacity, but can be avoided.by proper layout: or by the use of:directing baffles, . , . . . ... :... .... , Heait transfer depends'also upon the velocity of the medium in the tubes and upon its character, whether flowing water, condensing steam or evapo rating volatile refrigerant. Heat transfer rates expressed as Btu per (square foot of internal surface) (degree logarithmic mean effective tem perature difference between the fluid'and tube'Wall) are; for;example: about .150 to 300 for evaporating dichlorodifluoromethane, about 350 to 1200 for. water at 2 and b fps, and about 1200 for condensing steam. .. The.influence of the medium in the tubes on the overall heat transfer rate is therefore apparent. : ;: Because of these variables, reliable rating and performance infonpation for any design of coil must be. based on actual tests on that coil under the expected conditions of operation. A comparison between the performance of two designs, unless based on such tests on each, may lead to'entirely erroneous conclusions. Details on coil calculation and performance follow. Air Heating and Cooling Coils o;. Hoi T'lAi j:; 813 PERFORMANCE OF HEATING AND DRY COOLING COILS The performance ,of heating and dry coding coils depends in general upon: "" ' ' ; ,' 1. The overall coefficient of heat transfer from the fluid'within the coilto the air it heats or cools, . ...... . ., . .... . . ...... , 2. ,The,mean,,teniperature difference between the fluid within the coil and the air flowing over the coil. ' 1 ........... , . . '. ,. '3. The physical dimensions of the coil. . ..,. , . ; Thus,'for any one definite operating condition, the heating or cooling capacity of!a >given 'cod )is' expressed by the.following basic formula: . '" '.7'; \= r> x fAtp.) k .i xN; 7 '77777' a) where . .. qt = total heat transferred by the coil, Btu per. (hour) (square foot of coil face .- . Uarea)..-., -I, . . -.. overall coefficient <if;heat; transfer,-Btu:per (hour) (square foot of external . . ' c.oil:'Surface):(Fahrenheit; degree, temperature*: difference, between. the fluid within the.coil and.the air,flowing over, the,coil).: . Ma = mean temperature difference, Fahrenheit degrees, between the fluid within Ithe coil'and the air,passingover.it. .(Thisiis commonly taken as the loga- i ,;;i rithinic mean temperature'difference). .. : external surface areaof the givehi'coil; square feet,per (square foot of;coil ' face;area); (rowpficoil depth).1 ' ; i; N = dumber, of: rowsidf icoil 'depth. . - : ; ; ;, . . ,]:' . > Overall Coefficient of Heat Transfer , Of all factors affecting the performance of heating or dry cooling coils, the overall coefficient of heat transfer is the most difficult to determine, as it is influenced by several factors'which depend upon coil design and con ditions of operation.. ... ,, , .. Considering'any coil' whether of bare pipe or of finned type, the overall heat transfer coefficient for a given size and desijgh of coil caih Always be considered as a combined effect of three individual heat transfer coef ficients, namely: .1 __^ uuvmuHiuu ui iicrtu uiauflioi uctwctju air nuu me external suriace ot the coil, usually given in Btu per (hour) (square foot external surface) (Fahrenheit degree mean- temperature, difference). ,:, etc2.. Th.e coefficient of heat trans.fer t.hro.ugh the coil materia l--tube wall, fins, ribs, ", 3: The film' coefficVeht'dthd&t' transfer between'the internal' surface of the coil and the fluid flowing within'the?coil; usiially'givehiin Btu per (hour) '(square foot internal surface),(Fahrenheit,degrpejmean temperature difference). : r . These three individual cbefficients acting in series result. in ap overall coefficient of heat transfer in accordance with l>he basic,la.Ws given in Chap ters 5 and 9. For a hare pipe coil tHe overall coefficient of heat transfer, whether for heating or for-cooling (without-dchumidification), can be ex pressed by a simplified basic formula as follows: : ' 'U RL l+i (2) 814 CHAPTER 36 1954 Guide where - . ` U = overall coefficient of heat transfer, Btu per (hour) (square foot external surface) (Fahrenheit degree mean temperature difference between air 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 sur . face) (Fahrenheit degree mean temperature difference between that surface : and the average fluid temperature). /o = film coefficient of heat transfer between air and the external surface of the coil, Btu per (hour) (square.foot external surface) (Fahrenheit degree mean temperature 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). L = thickness of tube wall, inches. R = ratio between external and internal surface of the bare tube, usually vary : ing 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 co efficient of heat transfer on the basis of external surfaced Frequently, when pipe or tube walls are thin and of material having high conductivity (as is the case in construction of typical heating and cooling coils) the term L/k in Equation 2 becomes negligible and is gener ally 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: U = * , J. fi + Jo For finned coils the formula* for the overall, coefficient of heat transfer can be conveniently written: ' in which the term 17, called the fin efficiency, is introduced to allow for the resistance to heat flow encountered in the fins. The term R, in this case, is the ratio of total external surface 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. In the discussions which follow, coefficients/i and ?//,, will be considered sepa rately, and also various ways of combining them will be outlined. The performances of all heating and dry cooling coils are influenced by these same factors. But, when cooling coils operate wet or act as dehumidifying coils, the performance cannot be predicted on the basis of overall coefficients, and an analysis must be made on the basis of individual film coefficients as will be explained. Air Heating and Cooling Coils :' 815 PERFORMANCE OF DEHUMIDIFYING COILS When a cooling coil operates with a surface temperature which is below the dew-point of the air entering the coil, moisture is condensed and the air leaves the coil with a humidity ratio lower than it had when it entered the coil. To understand the performance of surface coils under such con ditions, assume that air enters a cooling coil at conditions corresponding to point 1 in Fig. 12. As long as the surface temperature of the coil is above the dew-point, the air is cooled without dehumidification, and its condition leaving the coil will be somewhere on line 1-A. Its exact-position on this line depends on the air velocity and the external film coefficient, as well as upon the surface temperature. When the surface temperature just equals the dew-point, the air leaves with conditions represented by point A. If the surface temperature is below the dew-point, condensation takes place, and the air has a final condition somewhere along the line A-2-3 which is a F .ig 12. Performance of Dehumidifying Coil line at a constant horizontal distance from the saturation curve. It should be understood that the line 1-A-2-3 is not intended to represent the path of the condition of the air as it passes through the coil from row to row. It is simply the path traced by the exit air conditions as -the surface temper ature is gradually reduced, with other conditions remaining constant.3 In the process of dehumidification, since heat is being transferred to the coil surface by two different mechanisms (convection and condensation), t is evident that an overall coefficient of heat transfer cannot be deter mined by the same method used for heating and for dry cooling coils. However, if it is assumed that the sensible heat transfer of a dehumidifying coil is unaffected by the presence of moisture on its surface, Equation 5 may be obtained to express this part of the heat transfer in terms of the external film coefficient and the surface temperature. where q. = foXAXNX (Ai,,) (5) ? = sensible heat transferred, Btu per (hour) (square foot of coil face area), h = dry-bulb temperature of air entering coil, Fahrenheit degrees, h = dry-bulb temperature of air leaving coil, Fahrenheit degrees. - f* = average temperature of coil external surface, Fahrenheit degrees. 816 CHAPTER 36 r.hihmO in;, ; 19,5.4'Guide At, - logarithihic meanstemperature diffefenceSfietween ^ir.'affdJcpil surface = : --i/a -i'lf' 4. -I ' tl`-- ta , log. U i: . i 'u-i. \ If ; Equation. 5 is .combined with another equation;,expressing; sensible . heat..transfer in terms ,of mass velocity and temperature difference,:the variables may be. arranged in the. following form ;(jwhich;is useful,for the solution,of dehumidification problems and fbrthe,'determination, of /,, from test data): 1: [>;! if.. foANih -- t;) = 0.243G(ii --`li) ,ii - b u log' t.j ti ~^ ia foAN ll -- ta 0.243G = log. ta ~ Is (6) where 0.243 G specific heat cjf humid air, Btu per (pound) (Fahrenheit degree), air mass velocity, pounds per (hour) (square foot of coil face area). i ... ; An examination of Pig. 12 will reveal that when i, is at the dew-point of the entering air: j , j *c i h ~ ta _ <i -- <dpi j ' | ta t ta idpl ; ' and when U is below the dew-point: ' ' . ! , . ... tl ta 11 <;|,,I . ta ~ ta ta -- idpS . . ,;;Therefore, Equation. 6imay be'written in its most useful form 'as.,. .. j l! .i'i'.i ;fy-y -tl - tap. , U - t. ' f-,in'i.m.-- n>i jo og'ti;-tdp.'7; s`ta'-ia']: r where : ; ,..... ,, ... i(j " ta' = 'minimum dryi-biiR) possible witHo'ut dehumidification, Fahrenheit degrees, 'j.idpi =.dew-point ofair entering`coiliFahrenlieit degrees':'' ... fjps = dew-point of,air leaving coil, Fahrenheit degrees. ,- ,|j ' This ecpiatiorimay be used to-establish a. line, as A-2-3,; for> a: given coil if/o is-Known for'the coil;'6r it'may he-used to'determine'jisfrofn teH'daih for the purpose of rating coils[The use of this;equationfbr'coil; selection'is illustrated in Example 1 at,the end of the chapter. Equation 7 is also important as a means of determining the external film coefficient. External Film Coefficient .. , While formulas shave-been,developed expressing the film coefficient jo for air passing parallel: to; a plane surface, they cannot be .used directly.for fins on tubes because of,air,turbulence, and.because of the temperature, gradient Air Heating and Cooling Coils 817' prevalent from the edge of a fin to its center. It is therefore necessary,'to make tests to evaluate the combined term ij/,,. The term, ??/,,, will be written merely /,, in this discussion, as there is no necessity for separately evaluating ij, and because values of /0 are usually applied only to the partic ular coils for which tests are made. I,!,-.:,-- The air side coefficient,of a:coil of particular .dimensions.,is;an, expon ential function of the mass velocity of the air: - J, = ZG` : " ^ ' (8) where . ; :, {,,a-t 7 jfo = film coefficient of beat transfer, Btu per (bour) (square foot external surface) (Fahrenheit degree mean temperature difference between air and average surface temperature). ' .V G = air mass velocity, pounds per (hour) (square foot of coil face area). Z.and n = constants which depend upon both air turbulence and surface arrange. ment. , Evaluation of constants Z and n may be accomplished through the use of test data in Equation 7 which gives values of /<, directly from the results of any wet coil test. If /,,, calculated in this mannerp is' plottediagainst values of G which prevailed during the tests, a straight line should result on logarithmic coordinates. The slope of this line is the value of n.. The value of Z may then be determined by direct substitution in Equation 8. For finned coils of different designs, values qf\Z`Siid h are extremely vari able; depending on the particular design and arrangeihent ofithe pbil surface. Therefore, it is desirable that theise constants be deterniined dire'ctly from test data for each type of coil surface. . . : ^ -- i: ' Internal Film Coefficient tu-ri -ii The internal film coefficient,/! which appears in Equatioh 3, is evaluated in .various ways, depending upon the nature of the fluid, and whether the fluid is changing state. . : ' '' ']' : ' . When, evaporating refrigerants are used in tubes, the temperature of the fluid is'fairly constant, being affected principally by pressure drop through the tubes, by superheat of the evaporated'refrigerant, and'By the presence of oil in solution. To obtain maximum coil capacity it is necessary to keep the pressure drop through the tubes at a minimbni,'to keep the superheat as low as possible without carrying liquid'back tb the icompressbr,' And1 to arrange for good separation and return of,oil,to;,the compressor. Another important factor is the removal of gas to keep the tube surface flooded with liquids as5 much'as possible. The internal film coefficient is: markedly- in creased by heavy heat loads, because;the increased:turbulence'and gas velocity cause good contact of the liquid with 'the -tubes. 'Values of /; usually lie between 150 and 450. For rating Of ;dehumidifying coils, satis factory results are obtainable by first determining the average external sur face temperature from Equation 7, and then Using the difference between fhe external film temperature and. the' refrigerant for' evaluating fi in Equation 9. ' : - 9i /i = ANH{t' l,) (). 818 CHAPTER 36 1954 Guide /i = internal film coefficient of heat transfer, Btu per- (hour) (square foot of internal tube surface) (Fahrenheit degree). ,. (, = average refrigerant temperature, Fahrenheit degrees. , To evaluate /1 by this method the same tests that were.required to determine/.may be used. "' .'When water is the cooling medium in tubes, the rate of heat transfer is a function of its velocity, which influences the number of contacts of the water molecules with the tube surface, per unit of time. Increased water velocity and reduced tube diameter cause increased heat transfer. Heat transfer is also greater at higher temperatures of the, water. The basic formula for the film coefficient of heat transfer for flow, of water in smooth tubes is as follows: p in* " " '' . /i = 1-5(1 + 100) -- . (10) where V = water velocity, feet per second. :. . D -- internal diameter of tube, inches. . 1 = average water temperature, Fahrenheit degrees. ' Equation 10 should not be used when Reynolds number: is less than 2000. Since, in the case of finned tubes using water as a refrigerant, test values of /i based on the calculated surface temperature for the entire coil may be lower than those obtained by use of Equation 10, actualtest results,are preferred if available. .. , \ , When saturated steam is condensed in the tubes of coils, the film coef ficient fi varies from 1000 to 2000, depending on freedom from air in the steam, and upon good drainage of the tubes. The coefficient is fairly con stant for a particular coil, giving values of (t, -- ,) that are directly propor tional to qt. However, if water coil test results are analyzed on a row-by row basis good agreement with Equation 10 will result.4 The use of turbulence prompters increases the value, of f-, for liquids in tubes at the expense of pressure drop. The increase obtained depends upon the type of turbulence promoter and the rate of flow. No general state ment can be made regarding their use, and it is best to refer to detailed papers on this subject for further information.4- 6 , Determining Size of Cooling Coil To illustrate the use of individual film coefficients in coil calculations, the.procedure for selecting the proper size cooling coil and for determining exit air condition, coil, surface temperature, total coil load and refrigerant temperature, is outlined in Example 1. Example 1: An industrial application requires the cooling of a certain quantityof air from a condition of 102 F dry-bulb and 85 F wet-bulb to a final condition of 80.5 F dry-bulb and 73 F wet-bulb. The air velocity across the coil is to be 400 fpm and coil data are as follows :/o = 10.7 at 400 fpm,/i = 325, external surface area = 15 sq ft per (square foot of face) (row of coil depth), ratio of external surface area to in ternal surface area = 15. . Solution: (1) Lay out the problem psychrometry as indicated in Fig. 13 and note that the minimum horizontal distance between the load ratio line and the saturation curve is 1.8 F dry-bulb at point A Fig. 13. This means that f, -- teBi in Equation / AirHeating and Cooling Coils a: 819 must not be less than 1.8 Therefore,-Equation 7 should be solved for N to deter mine the proper number of rows to be used for the coil. v a ior tv to deter- foAN 0.243G U- <d,i , 102 - 80 . t*-- tdp2 -' ,0- Si -- 1--.8--. = log. 12.22 = 2.5 Then substituting values for f,, A and G, N may be found as follows: 10.7 X 15N 0.243 X 1740 = 2.5 from which, N = 6.58 (2) This establishes the maximum whole number of coil rows that can be used as 6, and it is now possible to determine the actual location of the exit air conditions from Equation 7 by solving for the actual value of (, -- fdpi for a 6 row coil. v 1 : 10.7 X 15 X 6. _ 102-80 0.243 X 1740 " g U - U& 2.275 This establishes values of 9.78 for ^- = B and 2.25 for It -- tdvi- h -- `dpi (3) Next, the exit air condition at 57.3 F dry-bulb and 56 F wet-bulb as shown at B, j? 'und by locating a point on the load ratio line at a horizontal distance of-2:25 ory-bulb degrees from the saturation curve. . (4) .The,surface, temperature may now be found from Equation 7 which may also be written as ' . . where' Bit ~ t\ " B- 1 .- , B -- Alp* 820 CHAPTER 36 ftns 1954-GuidjB. : " 9.78 X 573 102 = g23 . ' ` O <70 ' ' (5) The total coil load may be calculated from the enthalpy difference across the coil and the air quantity using the weight of dry air instead of the weight'of the mixture. g, = G. (5, - h,).= 1700,(49.24 -,23,77), ... jo onn n__\ ft rtf forto areal ,, ;rfT where . ..................... . (7,, = weight of dry air per (hour) (square foot of coil face area). Si = enthalpy of air vapor mixture entering coil, Btu per pound of dry air. Ss = enthalpy of air vapor mixture leaving coil, Btu per pound of dry air. (6) The refrigerant temperature may be found from Equation 9 43,200 ----- (t. _ l,) =22.1 .. 325 15 X 6 X -^r Therefore,'ir = (52.3 -- 22.1) 3_ 0.2. Thus a coil 6 rows deep, operating at a refrigerant temperature of 30.2 F and a face velo'ciiy of 400 fpin', is required; and it will carry a total load of'43;200 BtU`per (hour) (square foot of face area). The air conditions leaving the coil are too low for the con . ditions of the problem and therefore it is necessary to by-pass air at the entering condition to obtain the desired result of 80.5 F dry-bulb ana 73 F wet-bulb. Although the preceding solution is satisfactory, it may be more desirable in some cases to use a higher refrigerant temperature and employ reheat to obtain the de sired load ratio. Such a solution is shown in Fig. 14. In this case, the coil load ratio line intersects the saturation curve and, therefore, a coil of any depth may be seleIfctaedc.oil depth of 6 rows is maintaine' d, th. e exi,t air conditions for the coil are in. di- Air Heating and Cooling Coils 821 cated at point: B, pig. ,14 as ,72.3 F. dryTbulb and 70.8 F wet-bulb,, and; the.surface temperature will be ............ 9.78 X 72.3 - 102 J. ; " 8.78 ' ' 69.0. The coil load will;be: 5t;= ,1700.(49.24 -- 34.661= 24,800,Btu per (hour) (square foot of face area) and the rpbrjgerant .temperatme. will.be found .from Equation 9: , , 24,800 W . - tr) '"'325 *.x 6 x is 12.7 i"- Therefore, /, = 69.0 -- 12.7 = 56.3. " = ' Thus, for the case where reheat .is used, a coil 6 rows deep.operating.at a refrigerant temperature of 56!.3 F is required^ The total coil load wdl be 24,800, Btu per (hour) (square foot of face area) but the actual effective load will be less by the amount of reheat required.' Therefore','for a given load, a larger coil and'more refrigerating capacity are required when reheat is used. '' ' 1 LETTER SYMBOLS USED IN CHAPTER 36 i) = fin efficiency. ' .' . /. A = external area of, coil.square feet per (square foot of coiljface 'area) . (row . of coil depth)., .. . ... - __ tl , --` fdpl . .- . - ', ' ' . b -- fdpS ; ' 1: `' ' V. D -- internal diameter of tube, inches. G = air mass. velocity, pounds per i(hour) (squareifoot of coil face area). ',' ' = G, = dry air mass'velocity, pounds dry air per (hour),'(square foot of ceil' face, area). .............................. ji = film coefficient of heat transfer between fluid and internal coil surface, Btu per (hour) (square foot internal surface) (Fahrenheit degree mean temperature between fluid and surface). /o = film coefficient of heat transfer between air and external coil surface, . ' Btu per (hour) (square foot external surface) (Fahrenheit degree mean . temperature difference between air and coil). - - -- h\ -- enthalpy of air-yapor mixture entering coil, Btu per pound of dry air. ht = enthalpy of air-vapor mixture leaving coil, Btu per pound of dry air. k -- conductivity of pipe or tube material, Btu (square foot) (hour) (Fahren heit degree per inch thickness). L = thickness of tube wall, inches. IV = number of rows of coil depth. n = a constant, exponent of G in Equation 8, obtained by plotting, on loga rithmic coordinates, G against values of /0. The value of n is the slope of the line. S* = sensible heat transferred, Btu per (hour) (square foot of coil face area). St = total heat transferred by coil, Btu per (hour) (square foot of face area). = ratio between external and internal surface of tube, f = average water temperature, Fahrenheit degrees, b = dry-bulb temperature of air entering coil, Fahrenheit degrees, b = dry-bulb temperature of air leaving coil, Fahrenheit degrees. CHAPTER 36 i : yj-J1954 Guide 822 t. '= minimum dry-bulb temperature possible without dehiiinidi^cation, Fahr enheit degrees. ' idp, = dew-point of air entering coil, Fahrenheit degrees, tdpi = dew-point of air leaving coil, Fahrenheit degrees. lr average refrigerant temperature, Fahrenheit degrees. (, = average temperature of external surface of coil, Fahrenheit degrees. Aim = mean temperature difference between fluid in coil and air passing over coil, Fahrenheit degrees. . Note: Ata is usually the logarithmic mean-. . At0 = logarithmic mean temperature difference between air and coil surface. U = overall coefficient of heat transfer, Btu per (hour) (square foot of exter nal coil surface) (Fahrenheit degrees temperature difference between fluid in coil and air flowing over coil). , V = water velocity, feet per second. . Z = a constant for .use in Equation 8. obtained, by. plotting on logarithmic coordinates G against values of /<,. ! ... , Note: Numerical subscripts refer to condition, entering and leaving, respectively.' . .. . .................... REFERENCES 1 Reheating by Means of Refrigerant Compressor Discharge Gas, by S. F. Nicoll (A.S.H.V.E. Transactions, Vol. 47, 1941, p. 239). * Rational Development and Rating of Extended Air Cooling Surface, by H. B. Pownall (Refrigerating Engineering, October, 1935, p. 211). 'Performance of Surface-Coil Dehumidifiers for Comfort Air Conditioning, by G. L. Tuve and L. G. Seigel (A.S.H.V.E. Transactions, Vol. 44, 1938, p. 523). 4 The Effect of Turbulence Promoters on Heat Transfer Coefficients for Water Flowing in Horizontal Tubes, by L. G. Seigel (A.S.H.V.E. Transactions, Vol. 52, 194`6,Mpa. x1i9m7)u.m Rate of Heat Transfer with Minimu. m Loss of Energy, by Z. Nagoaka and A. Watanabe (Proceedings, International Congress on Refrigeration, 7th Congress, Vol. 3, No. 16, pp. 221-245, 1937). CHAPTER 37 REFRIGERATION Refrigeration Theory: Definitions and Basic Concepts, Refrigerants, Vapor Compression Refrigeration Cycles, Clearance and Volumetric Efficiency, Complex Refrigeration Cycles, Air Cycle, Steam Jet, Absorption and Ice Systems, Heat Pump; Basic Refrigeration Equipment: Compression Machines, Condensers, Evaporators and Coolers; Refrigeration Controls, Piping and Accessories; Equipment Characteristics and Selection WITH the increasing use of all-year comfort air conditioning instal lations, the importance of refrigeration to the air conditioning engineer has been greatly magnified. The details of equipment operation, mainte nance and design remain problems for the refrigeration engineer, but the air conditioning engineer does retain a responsibility to the customer which requires on his part some knowledge of the different refrigeration cycles and the relative merits of each. In order to assist in meeting this need, the present chapter has been divided into four parts, the first covering the fundamental technical relationships which govern the selection and analysis of an operating cycle, the next two presenting brief discussions of basic refrigerating equipment and auxiliaries, and the last, information on selec tion criteria. REFRIGERATION THEORY Definitions and Basic Concepts The ton of refrigeration is a quantity unit which originated in the days when harvested ice was the principal source of summer cooling. By defi nition the ton is the cooling effect realized when one ton of 32 F ice melts to water at 32 F; since the latent heat of fusion of ice is 144 Btu per pound, the ton represents a unit cooling effect of 144 X 2,000 = 288,000 Btu. In common practice the ton is usually considered a rate (rather than quantity) unit, and is taken as 288,000 Btu per day (24 hours), or 12,000 Btu per hour, or 200 Btu pier minute. Thus for air conditioning calculations, the size of the requisite refrigeration machine, expressed in tons, can be obtained by dividing the heat gain of the structure, expressed in Btu per horn-, by 12,000. In equation form: where Ht ~ (Btu per hour heat gain) + 12,000 (1) ' Hi ~ load in tons. The working substance, or refrigerant, is the fluid which carries heat through the refrigeration cycle from the evaporator, where heat enters the refrigerant, to the condenser where the heat is discharged to some cooling Medium. The great majority of modern refrigeration systems use.a liquefiaWe vapor as the working substance. By altering the pressure of the refrigerant its boiling temperature is changed, allowing the material to boil y"e evaporator at a temperature sufficiently lower than that of the con htioned SDace. to inslire maintenance of an effective heat transfer rate from 824 CHAPTER 37 1954'Guide the space (or in some cases from a secondary cooling fluid such as brine or cold water) to the refrigerant. The vapor formed in the evaporator is then raised in pressure (by a compressor, or by the absorber-generator com bination of the absorption system) until its new. boiling temperature exceeds the temperature of the available cooling medium: Under these conditions, heat transfer is established from the refrigerant vapor to the cooling medium with resultant condensation of the refrigerant. When condensed, thehigh- pressure liquid--refrigerant is reduced in pressure and again allowed to boil in the evaporator. ` ' In order to. permit evaluation of the effectiveness with which, any given cycle operates, some term is desirable which wordd be comparable to the efficiency that is used for heat engines..., In refrigeration the desired effect is heat extraction, and the cost of achieving this extraction is the amount of energy which must be supplied as shaft work! Thus the ratio of refrig erating effect to the heat equivalent of the compressor work is used as a measure of effectiveness, and is defined as the coefficient, of performance. _ v lf the desired^effect-is the rejection of-heat through the condenser instead of heat extraction through the evaporator, the refrigeration system is then termed a heat. pump. In this case-the coefficient of performance is the ratio of the heat rejected from the condenser to the heat equivalent of the compressor work. The coefficient of.performance for the heat pump is greater than that for a system operating as a refrigeraiing machine, because all mechanical shaft work required to operate the compressor is dissipated asmSeful heat through theeondenser. , - :. ' The Carhot cycle, an ideal; thermodynamically reversible Cycle consisting of an adiabatic expansion and an isothermal expansion, followed by an adiabatic compression and an isothermal compression to form a closed'cycle, may be shown to be a measure of the maximum possible conversion of heat energy into mechanical energy. In its reversed form it is a measure of the maximum performance possible for any refrigeration cycle operating either as a refrigerator or.as a heat pump. Although it cannot be applied ini an actual machine because, of the impossibility of obtaining complete reversT bility, it: is, .nevertheless, extremely valuable as a. criterion of inherent limitations. . The coefficient of performance (CP) of a reversed Carnot cycle system-operating as a refrigeration system is.. . -: . (CP) - . r. T,,-T. (2) where . .. , , . . ................ . ... .. , .. T, = evaporator temperature, Fahrenheit degrees, absolute. T, = condenser temperature, Fahrenheit degrees, absolute. With the ideal Carnot cycle operating as a heat pump, the coefficient of performance is .' Tc (CP) = Pc - T. . ... (3) The Carnot cycle coefficient of performance for both a refrigerating machine arid a heat pump increases as the spread between the evaporator and the condenser temperatures decreases. In general, the same is true for'ari actual system operating as either a refrigerating machine or a heat pumfij Refrigeration 825 Refrigerants A desirable refrigerant should possess chemical, physical, and thermo dynamic properties which permit, its efficient application in refrigerating systems. In addition, when the volume 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 vaporization since it is this heat quantity--subject to minor variations--which constitutes the working effectiveness of the refrig erant. Further, since 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 iow-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 excessively high (to prevent need for extra-heavy construction). The specific volumespecific enthalpy relationship is also important because some materials would have such low density, when in vapor form, that impractical com pressor displacements would be needed to handle the suction vapor. Properties of refrigerants are usually given either in tabular 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 pressure-enthalpy chart. The advantage of, pressure-enthalpy plotting is that linear distances on the chart correspond to energy gains or losses, and the two types of processes, constant-pressure and constant-en thalpy, which occur most frequently in refrigeration cycles, can both be represented- by straight vertical or horizontal lines. Figs. 1 and 2 present pressure enthalpy charts for dichlorodifluoromethane (Freon-12) and monochlorodifluoromethane (Freon-22), respectively. Although tabular- ar rangements of refrigerant properties require interpolation between .values, they have the advantage of an accuracy greater than that obtainable from a chart. Tables 1, 2, and 3 give the thermodynamic properties of three of the more Common refrigerants used in air conditioning installations: dichlorodifluoromethane: (Freon-12), monochlorodifluorometharie (Freon22) and monofluorotrichloromethane (Freon-11); the first two of these are commonly used in reciprocating compressors; the last refrigerant is used in centrifugal machine's. Referring to Table 1, the first column gives the range of saturation tem peratures likely to occur in practice. The second column gives the satura tion pressure expressed in pounds per square inch absolute corresponding a given temperature, while the next six columns give the three funda mental specific properties, volume, enthalpy, and entropy, of the saturated liquid and,saturated vapor, respectively. The last 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 50 F superheat means, not that toe gas is at a temperature of 50 F, but that its temperature exceeds by 50 deg the saturation temperature corresponding to its actual pressure. Thus, h-12 vapor at 38.0 psig and 91 F possesses 50 deg of superheat, since its saturation temperature corresponding to 52.7 psia is 41 F. The-tabular arrangements of refrigerant properties are literally for satu rated or superheated materials only. In many cases, however, the engineer must work with sub-cooled liquids. With an accuracy sufficient for all Practical purposes, the specific volume and the enthalpy of any sub-cooled 826 CHAPTER 37 1954 Guide refrigerant can be taken as equal to the values read from the tables for a saturated liquid at the same temperature. Thus, if F-12 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 wet vapor or of a mixture of liquid with some added vapor, such as is found at 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. Refrigeration 827? Table 1. Properties op Dichlorodifluoromethane (F-12) . Sat. Temp. F Abs. Press. Lb psb So In. liquid Etitqalpt and Entropy Taksx From --40 F .Enthalpy . Entropy 25 F Superheat . 50 F Superheat. . Vapor. liquid Vapor Liquid Vapor Enthalpy Entropy Enthalpy Entropy 0 . 23.87 0.0110 2 24.89 aono 4 25.96 0.0111 5 26.51 0.0111 6 27.05 0.0111 1X37 1X74 1X14 1.485 1.457 8X5 8.67 9.10 9X2 9X3 78X1 ; 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 82X9 8141 0.17829 0.17812 0.17795 0.17786 0.17778 85.26 .85X1 85.76 85X9 86X1 0.18547. 0.18529 0.18511 0.18502 0.18494 8 10 12 14 16 28.18 29.35 30.56 31.80 33.08 . C.0111 0.0112 0.0112 0.0112 0.0112 1.403 1X51 : 1X01- 1X53 1.207 . 9.96 10X9 . 10X2 11X6 11.70 79.13 79X6 79X9 79X2 80.05 0.02235 0.02328 0.02419 0.02510 0.02601 0.17030 0.17015 0.17001 0.16987 0.16974 82.66 8190 83.14 83X8 ,83.61 0.17763 0.17747 0.17733 0.17720 0.17706 86X6 - 86X1 86.76 87X1 87X6 0.18477: 0.18460 018444 0.18429' 0.18413 18 20 22 24 26 34.40 35.75 37.15 38X8 40.07 0.0113 0.0113 0:0113 0.0113 0.0114 1.163 1.121 : 1.0S1 1.043 1.007 12.12 80.27 12X5 80.49 13.00 . 8072 13.44' 80.95 13X8. 81.17 ` 0.02692 0.02783 0.02873 0.02963 0.03053 0.16961 0.16949 0.16938 0.16926 0.16913 83X5. 84.09 84X2 84X5 84.79 0.17693 0.17679 0.17666 0.17652 0.17639 87X1 .87.76 88.00 88X4 88.49 0.18397 0.18382 0.18369 0.18355 0.18342 .28 30 32 34 36 38 39 40 41 42 44 46 48 SO 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90 92 94 96 98 too 102 104 106 .`108 110 112 114*. U6 118 120 122 124 126 128 130 132 134 136 138 HO 41X9 43.16 44.77 46.42 48.13 49.88 50.78 51.68 52.70 53.51 55.40 57.35 59X5 6U9 63.49 65.63 67.84 70.10 72.41 . 74.77 77.20 79.67 82X4 84.82 87.50 9120 93.00 95.85 98.76 101.70 104.8 107.9 111.1 114.3 117.7 121.0 124.5 128.0 131.6 135.3 139j0 142X 146X 15a7 154^8 158.9 163.1 167.4 171.8 176.2 180X 185.4 190.1 194.9 199X 204X 209.9 215.0 220.2 0.0114 0.0115 0.0115 0.0115 0.0116 0.973 : 0.939 i . 0908 0X77 0.848 14X2 14.76 15X1 15.65 1610 0.0116 0.0116 0.0116 0.0116 0.0116 0X19 16X5 0X06 -- --16.77 0.792 17X0 0.779 17.23 0.767 17.46 0.0117 0.0117 0.0117 0.0118 0.0118 0.742 0.718 0.695 0.673 0.652 17.91 18X6 18X2 19.27 19.72 0.0118 0.0119; 0.0119 0.0119 0.0120 0632 0.612 0X93 0X75 0X57 20.18 20.64 21.11 21X7 2103 0.0120 02)120 0.0121 0.0121 0.0121 0X40 0X24 : 0,508 a493 0.479 2149 2195 23.42 23.90 24X7 0.0122 XX122 0.0123 0.0123 0.0123 0.464 0.451 0.438 0.425 0.413 24.84 25X2 25X0 26X8 26.76 0.0124 0.0124 0.0124 0.0125 0.0125 : o.4oi 0.389 0X78 0X68 : 0X57 27X4 27.72 28X1 28.70 29.19 0.0126 0.0126 0.0126 0X127 0.0127 0.347 0X38 0X28 0X19 0X10 29.68 30.18 30.67 31.16 31.65 0X128 0X128 0X129 0X129 0X130 0X02 0.293 0.28S 0.277 0.269 311S 3165 33.15 33.65 34.15 0.0130 0X131 0.0131 0.0132 QX132 0262 0.254 0.247 0.240 0.233 34.65 35.15 35.65 36.16 36.66 0X133 0X133 0.0134 0.0134 0X135 0X27 0.220 0X14 0.208 0.202 37.16 37.67 38.18 38.69 39.19 0X135 0X136 0X137 0X138 0.196 0.191 0.185 0.180 39.70 40X1 40.72 41X4 81X9 81.61 81.83 8105. 8127 0X3143 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 89X1 89.45 89.68 0.18328 0.1831S ai8303 0.18291 0.18280 8149 8160 8171 8182 82.93 0.03591 0.03635 0.03680 0.03725 0.03770 0.16843 0.16838 0.16833 0.16828 0.16823 86.18 86X9 86.41 86X2 86.64. 0.17566 0.17560 0.17554 0.17549 0.17544 89.92' 0.18268 .90.04 0.18262 90.16 0.18256 90.28 018251 90.40 0.18245 83.15 83X6 83X7 83.78 83.99 0.03859 0.03948 0.04037 0X4126 0.04215 0.16813 0.16803 0.16794 0.16785 0.16776 86X6 87.09 87X1 87X4 87.76 0.17534 0.17525 0.17515 017505 0.17496 90.65 90X9 . 91.14 91X8 91X1 0.18235' 0.18224 0.18214 0.18203 0.18193 84X0 84.41 84X2 84X2 85X2 0.04304 004392 0.04480 0X4568 0.04657 0.16767 0.16758 0.16749 0.16741 4X16733 87.98 88.20 88.42 88.64 88X6 0.17486 0.17477 0.17467 0.17458 0.17450 91X3 : 92X6 92.28 92X1 9174 0.18184' 0.18174 0.18165 0.18155 0.18147 85.22 85.42 85.62 85X2 86.02 0X4745 0.04833 0.04921 0.05009 0X5097 0.16725 0.16717 0.16709 0.16701 0.16693 89X7 89.29 89X0 89.72 89.93 0.17442 0.17433 0.17425 0.17417 0.17409 9197 93.20 93.43 93.66 93.99 018139 018130 0.18122 0.18114 0.18106 86.22 86.42 86.61 86.80 86.99 0.05185 0.05272 0.05359 0X5446 0.05534 0.16685 4X16677 0.16669 0.16662 0.16655 90.14 9036 90.57 90.78 90X8 0.17402 0.17394 0.17387 0.17379 0.17372 94.12 94.34 94X7 94X0 95.01 018098 0.18091 0.18083 0.18075 0.18068 87.18 87X7 87X6 ; 87.74 87.92 0.05621 0.16648 0.05708 0.16640 0.05795 0.16632 0.05882 0.16624 0.05969 0.16616 91.18 91X7 91X7 91.77 9L97 0.17365 0.17358 0.17351 0.17344 0.17337 95X2 95.44 95.65 95X6 96X7 0.18061 0.18054 018047 0.18040 0.18033 88.10 0.06056 0.16608 88.28 . 0X6143 0.16600 88.45 0.06230 4X16592 88.62 0X6316 0.16584 88.79 0X6403 0.16576 9116 92X6 9155 9175 9193 0.17330 0.17322 0.17315 017308 0.17301 96X8 96.50 96.71 96.92 97.12 0.18026 0.18018 018011 018004 0.17998 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 93X0 93.48 93.66 93X2 0.17294 0.17288 0.17281 0.17274 0.17266 97X2 97X3 97.73 97.93 98.11 017993 017987 017982 017976 017969 89.73 89X7 90.01 90.15 90.28 0.06922 0X7008 0.07094 0X7180 0.07266 0.16524 0.16515 0.16505 0.16495 0.16484 93.98 94.15 94X1 94.47 94.63 0.17258 0.17249 0.17241 0.17233 0.17224 98.29 98.48 98.66 98X4 99X1 0.17961 017954 017946 0.17939 017931 90.40 90.52 90.64 9C.76 90X6 0X7352 0.0743? 0X7522 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 99X5 99X3 99.70 99X7 017922 017914 017906 017897 017889 90.96 91.06 91.15 91X4 0X7775 0.16411 0X7858 0.16396 0.07941 0.16380 0X8024 0.16363 95X6 95.72 95X7 96.03 0.17166 0.17156 0.17145 X17134 100.04 100.22 100X9 100X6 0.17881 0.17873 0.17864 0.17856 828' CHAPTER 37 ha = specific enthalpy of the mixture. hf = specific enthalpy of the liquid. At = specific enthalpy of the saturated vapor. 1954Guide Refrigeration 829 Table 2. Properties op Monochlorodiflooromethane (F-22) Ass Temp : Pres. F Sq In VOLUME -------------- Enthalpy and Entropy Taken froaI --40 F Enthalpy 50 Dec Superheat 100 Dec Superheat liquid, Vapo Llquit 1 Vapoj Llquit1 Vapo Enthal] y tropy Enthal] * tropy 0 38.78 6.01192 1.373 , 10.6J 105.05 0.0246 08292 112.35 0.2446 120.0C 08590 2 .4 5 6 8 40.43 . 6.01195 1.320 : 11.13 42.14 , 0.01198 - 1870 43.02 . 0.01200 43.91 0.01201 1.246 . 1.221 45.74 0.01205 . 1.175 11.7C 11.97 12.23 12.76 10584 105.45 105.56 105.66 105.87 0.0251 0.0262 0.0268 0.0274 0.0285 0.2286 0.2285 0.2283 0.22SC 0.2276 T12.5S 112.83 112.95 113.01 11381 0.2442 0.2438 08436 0.2434 08430 12086 120.52 120.65 120.76 121.04 0.2586 0.2581 08579 08577 08572 10 12 14 16 18 47.63 0.01208 .49.58 0.01211 51.69 0.01215 53.66 0.01218 55.79 0.01222 1.130 1.088 1.048 1.009 0.9721 1389 1382 14.36 14.90 15.44 106.08 10689 106.50 106.71 106.92 0.0296 : 08272 0.0307 0.2268 0.0319 0.2264 0.0330 0.2260 0.0341 08257 113.55 1X3.79 114.02 114.25 114.48 0.2426 0.2422 08418 0.2414 0.2410 121.30 121.56 121.82 122.08 122.33 08565 0.2564 08560 08566 0.2552 20 22 24 26 28 57.98 0.01225 60.23 0.01229 .62.65 0,01232 64.94 0.01236 , 67.40 .0.01239 0.9369 * 15.98 0.9032 : 16.52 0.8707 37.06 0.8398 17.61 0.8100 . 18.17 107.13 107.33 107.53 107.73 107.93 0.0352 0.0364 0.0375 0.0379 0.0398 08253 0.2249 0.2246 08242 08239 114.71 114.94 115.17 115.40 115.62 0.2408 0.2402 0.2398 0.2395 0.2391 122.59 122.84 123.10 123.35 123.60 0.2548 08544 0.2540 0.2537 08533 30 32 34 36 38 69.93 72.53 7581 77.97 80.81 0.01243 - -0.7816 0.01247 0.7543 0.01250 0.7283 0.01254 0.7032 0.01258 0.6791 18.74 19.32 19.90 20.40 21.09 108.13 10883 108.52 108.71 108.90 0.0409 0.0421 0.0433 0.0445 0.0457 0.2235 08232 08228 0.2225 0.2222 115.84 116.07 116.29 116.52 116.74 0.2387 0.2383 0.2380 0.2376 Q.2373 12385 124.10 124.35 124.59 124.84 0.2529 08525 0.2622 08518 08515 40 42 44 46 48 83.72 0.01262 86.69 0.01260. 89.74 0.01270 92.88 . 0.01274 96.10 0.01278 0.6559 21.70 0.6339 , 2289 0.6126 * 22.90 0.5922 1 23.50 0.5726 24.11 109.09 109.27 109.45 109.63 109.80 0.0469 0.0481 0.0463 0.0505 0.0516 0.2218 0.2215 0.2211 0.2208 08205 116.96 117.18 117.40 117.61 117.82 0.2369 0.2366 0.2363 0.2359 0.2356 125.08 125.32 125.56 125.80 126.04 08511 08508 08504 08501 0.2497 -50. 52 . 99.40 102.8 54 106.2 56 109.8 58 113.5 ' 60 62 117.2 121.0 64 124.9 66 128.9 68 1 133.0 0.01282 0.5537 0.01286 lt 0.5355 0.01290 0.5184 0.01294 0.5014 0.01299 ; 0.4849 24.73 2584 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 0.01303 i 0.4695 0.01307 , 0.4546 0.01312 ; L 0.4403 0.01316 . 0.4264 0.01320 0.4129 2783 28.46 29.09 29.72 30.35 110.78 .110.93 111.08 111.22 111.35 0.0588 0.0600 0.0612 0.0624. 0.0636 08201 08198 08194 08191 08188 0.2185 0.2181 08178 0.2175 08172 118.02 11882 118.42 118.62 118.82 119.01 11981 219.40 119.59 119.77 0.2353 *126.27 0.2350 126.50 0.2347 126.73 0.2343 126.96 A2340 127.19 0.2337 0.2334 0.2331 0.2327 0.2324 127.42 127.65 127.87 128.10 128.32 0.2494 0.2491 08488 0.2484 0.2481 0.2478 08475 08472 0.2469 0.2466 137.2 72 141.5 74 145.9 76 150.4 78 155.0 0.01325 0.01330 0.01334 0.01330 0.01344 0.4000 0.3875 0.3754 0.3638 0.3526 30.99 31.65 32.29 32.94 33.6) 111.49 111.63 111.75 211.88 112.01 0.0648 0.0661 0.0673 0.0684 0.0696 0.2168 0.2165 0.2162 0.2158 08155 119.96 120.15 120.32 120.50 120.67 03321 0.2318 0.2315 0.2312 0.2309 128.54 128.76 128.97 129119 129.40 08463 0.2460 08457 08455 0.2452 82 84 86 159.7 164.5 169.4 174.5 88 179.6 0.01349 0.01353 0.01358 0.01363 0.01358 0.3417 0.3313 0.3212 08113 0.3019 3487 34.92 35.60 36.28 36.94 112.13 11284 112.36 112.47 112.57 0.0708 0.0720 0.0732 0.0744 0.0756 08151 0.2148 08144 08140 08137 120.85 121.02 121.18 121.34 121.50 0.2306 0.2303 0.2300 08297 0.2294 129.61 129.82 130.02 130.23 130.43 0.2449 08446 08443 0.2441 08438 92 184.8 190.1 94 96 98 195.6 201.2 208.$ 100 102 104 106 108 212.6 218.6 224.6 230.7 237.0 no112 114 116 118 243.4 249.9 >56.6 s>7603..34 120 ; 77.3 0.01374 0.01379 0.01384 0.01390 0.01396 0.01402 0.01408 0.01414 0.01420 0.01426 0.01433 0.01440 0.01447 0.01454 0.01461 0.01469 0.2928 08841 0.2755 0.2672 0.2594 37.61 38.28 38.97 39.65 40.32 0.2517 40.98 0.2443 41.65 0.2370 42.32 0.2301 . 42.98 0.2233 43.66 0.2167 08104 (0.2043 ).1983 (0.1926 44.35 45.04 45.74 46.44 47.14 (0.1871 47.85 112.67 112.76 112.85 112.93 113.00 0.0768 0.0780 0.0792 0.0803 0.0815 08133 0.2130 08126 0.2122 0.2119 113.06 113.12 113.16 113.20 11384 0.0827 0.0839 0.0851 0.0862 9.0874 08115 0.2111 9.2107 98104 9.2100 113.29 113.34 113.38 113.42 13.46 13.52 9.0886 9.0898 9.0909 (9.0921 (9.0933 9.2098 9.2093 9.2089 (9.20S5 (9.2081 C9.0945 j (>8078 121.66 121.82 121.97 122.12 12286 0.2291 0.2288 0.2285 08282 0.2279 122.40 122.53 122.66 122.79 122.02 0.2276 0.2273 0.2270 0.2267 0.2264 123.04 123.16 12388 123.40 23.51 0.2261 0.2258 0.2255 98253 9.2250 23.62 (9.2247 130.63 130.83 131.03 13183 131.42 0.2435 02432 0.2429 0.2427 08424 131.61 131.80 131.99 132.17 132.35 0.2421 08418 0.2416 0.2413 0.2411 132.53 132.71 132.88 33.05 1338? 0.2408 0.2405 08403 9.2400 98398 ' 33.39 (9.2395 from Kinetic Chemicals, Inc., IMS 830' CHAPTER 37 1954 Guide Table 3. Properties of Monofluorotrichloromethane (F-ll) ' Enthalpy and Entkopt Taken Fbom --40 F Enthalpy Entropy -* 50 F Superheat Liquid Vapor. t En En- Entropy th&lpy tropy ----- 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 .97.4 *97.2 99.0 99.8 100.7 101.5 0.2120 0.2117 0.2114 0.2111 0.2109 0.2107 0.0307 0.0328 0.0349 0.0370 0.0391 0.1969 0.1968 0.1968 0.1967 0.1967 98.8 996 100.3 101-1 101.9 0.0412 0.0432 0.0453 0.0473 0.0493 0.1967 0.1967 0.1967 0.1967 0.1967 102.7 103.5 .1043 105.0 105.7 0.0513 0.1966 0.0533 1 0.1966 0.0553 0.1966 0.0573 0.1966 0.059: 0.1965 0.0613 0.1965 106.4 107.1 107.9 108.6 109.2 109.9 0.2038 0.2037 0.2036 0.2035 0.2034 102.3 103.1 103.8 104.6 105.4 0.2033 106.2 0.2033 107.0 0.2032 107.8 0.2032 ' 108.5 0.2031 109.2 0.2030 109.9 0.2029 110.6 111.4 112.1 1 112.7 113.4 0.2105 0.2103 0.2101 0:2099 0.2098 0.2097 0.2096 0.2094 0.2093 0.2092 0.2090 0.2089 0.2088 0.2087 0.2085 0.2084 Values of v, and va for use in Equation 4 can be obtained directly or by calculation from the tables of properties of refrigerants. By a reversal of this same procedure the tabular data can be used to determine the state of a mixture leaving an expansion valve. Consider a valve to.which saturated liquid at pressure p,, is admitted, and a mixture of saturated liquid and vapor at pressure p<i is discharged. The quality of the material at discharge is then determined by making use of the fact that the expansion processes completely irreversible, is a throttling process, and hence, occurs without change in enthalpy. Thus, the enthalpy of the mix ture, hm, is equal to the enthalpy of the saturated liquid at the entrance state, 7iis, and can therefore be read from the table. Thus, ' hi, = km -- hvd .(1 x) (Art -- hu) or, (6) -- (hm -- ha),+ (h*d hu) inhtere hi, = enthalpy of saturated liquid at entrance to expansion valve. ha = enthalpy of mixture. hvd -- enthalpy of saturated vapor at discharge. hid = enthalpy of liquid at discharge. x = proportion of liquid in the mixture, decimal. faSpoimr pCleomCypcrlees.sioTnheRerefrfirgigeeraratinotncyCcyleclies the series of state changes (which occur in the conditioning processes) needed to restore the refrigerant to a condition in which it will possess the ability to extract heat from the spa6 to be cooled. For all compression-type systems the cycle consists of fur processes: heat gain in the evaporator; pressure rise in the compressor; Refrigeration 831 heat loss in the condenser; pressure loss in the expansion valve. The com pression 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 expanding engine with consequent release of energy as shaft work. In ordinary sys tems, however, the additional first cost and maintenance costs of an expand ing engine so greatly exceed the advantage resulting from the work realized, that such engines are not used, and the pressure reduction is allowed to occur irreversibly in an expansion valve. Basically,'theny a refrigeration cycle consists of two heat transfer processes and two pressure change proc esses, no work entering into the heat transfer processes and--in the simple cycle--no heat transfer occurring during the pressure-change processes. The most common and least complicated type of refrigeration cycle is called the simple saturation cycle, and is shown diagrammatically in Fig. 3 and plotted upon pressure-enthalpy coordinates in Fig. 4. . For this system, Heat of Compression Added to Gas saturated vapor 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 irreversibly and without external heat transfer, is characterized by constant entropy. Thus, the state of the superheated vapor leaving the compressor b.e determined from the tables of thermodynamic properties by noting the discharge pressure and fixing, also, the entropy of the saturated vapor at entrance to the compressor. Superheated vapor from the compressor flows to the condenser where ae-superheating and condensation take place. From the condenser the rengerant flows to the expansion valve, undergoes a constant-enthalpy pres sure reduction, and returns to the evaporator where it again removes a Quantity of undesired heat. When the evaporator is arranged to permit irect cooling of room air by the refrigerant, the system is said to be of the jrecl expansion type, while a system in which the evaporating-refrigerant water or brine, which in tum cools the air, is said to be indirect. hough many differences exist between most actual systems and that of itn Slrn-P^e saturation cycle, this latter is; nonetheless, of great value in that Provides an extremely simple method of rapidly achieving an approximate 832 CHAPTER 37 ,.,1954, Guide 'it.- i-) ty.(-- t .'x analysis of probable power requirements, compressor size, etc... Eurthesj the equations used in analysis of a simple saturation cycle-form ,the'basis of: the more complex treatments required for compound refrigeration cycles. For these reasons a typical simple saturation problem will be worked in detail.- v . .. ; ; : Example 1: A simple saturation cycle carries a 7 ton load whenhperating between suction and discharge pressure of 52.7 psia'andT21 psia with F-12 as'the refrigerant. Determine: (a) the cooling effect provided by each pound of refrigerant; >(5); the-re frigerant circulating rate; (e) the horsepower required; (d) the quantity of heat'to be dissipated from the condenser; (e) the required,condenser coolingjwatei, in gallons per minute, if 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; (p) coefficient*of perform ance. . ... ... . . ..... .... . . ... >i:....., j Solution: (o) Saturated liquid F-12 at 121 psia leaves the condenser and enters the expansion valve. The enthalpy of this material (from Table .1)18:29.68 BtUjper pound, and this must also be its enthalpy at entrance to the evaporator! Leaving the evaporator as a saturated vapor at 52.7 psia, its enthalpy is 82.82, so the re frigerating effect must be 82.82 -- 29.68 = 53.14 Btu per pound. Fig. 4. Pressure-Enthalpy Diagram for Simple Saturation Cycle (b) The refrigerant circulating rate is equal to the total heat to be picked up in unit time, divided by the pick-up per pound of refrigerant or,. . W, = (7 ton X 200) -s- 53.14 = 26.3 lb per minute, '. ii:". (c) The horsepower required is equal to the increase in energy of the'refrigerahV passing through the compressor (expressed in Btu per minute) divided by the cony version factor 42.42, which is the number of Btu per. minute corresponding to 1 hp) ` ; . (hp) = IF, (As - A,,) + 42.42 ($ where. ' . .. .. . : 1 hp = horsepower. !' .. .. Wt = refrigerant circulating rate in pounds per minute. , Ad = enthalpy of vapor at condition of discharge from' compressor. .` At, = enthalpy of saturated vapor entering compressor.' . : . ;, . Wr is known from (A) and Av> is the enthalpy of refrigerant as it enters the com-; pressor in a saturated vapor state at 52.7 psia; thus hn = 82.82. , ...i In order to determine Ad, 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 same entropy at 121 psia. From the table the entropy of vapor superheated 25 deg Refrigeration 833 0.17330, so, the superheat,,(* possessed,by the,actual gas discharged frpm .this.com- 'presBor can be obtained1 by ihtefpjolation.as,' :. . . . : ... 0.16828 - 0.16608 " j '! . >>-- : ' >' '> 25 ~ 0.17330 - 0.16608 : from which 4d ,= 7.6 deg. ... y-,.,. ,.a. .. . ... As thie Saturation temperature at 121 .psia,is.Ol.^theiactuai .temperature,, U,.of :the vapor leaving the compressor is, U = 94 '+ `lid' = 94 -f '7.0 = 101.6 F. By the same kmd.of interpolation the.enthalpy of the discharged'vapor'can'be determined-from the enthalpies.giyen for vapor superheated>23 F.andifbriSaturatedivapor,;, f '> : (Ad^ 88.10)' ' :(0.16828 - 0.16608) ;`("y1' !',y ; '""'y ; : `" (92.16 - 88.10) ~. (0.17330 - 0!l6608) ` '. from'which, Ad ='89.34:Btu |>er pound. > : r : > >.>, Then.substituting in-Equation 7,;> ii !'+'>'> * - ': i *?i ! (hp) = 26.3 (89.34 - 82:82) -V 42.42 = 4.03. :'! : (d) The rate of heat loss from the condenser, Q,, must be equal to the sum of the energies picked up by the refrigerant in the evaporator,and .the.compressor, .,,, , Q. = 53.14 + (89.34 - 82.82) = 53.14 + 6.52`= 59.66 Btu per pound or 26.3 X 59,66 = 1569,Bfu;per minute.,.-.This same figure>can; of course, be: determined more directly !by:subtraction qf the enthalpy .of,liquid,leaving the condenser from the enthalpy of superheated vapor going into it1, thus, '. , ... j; . . " ... ,: Qc -- 26.3,(89:34 -- 29.f>S) --1569 Btu per minute. ` (e) The cooling,Water rate1 (based pn a gallon as 8.34 lb) ,is !1569 -e (8 X 8.34) = 23.5 gpm. ;:i>;-.! >.>;.: la.'li : > >r.i: : (f) The compressor size infixed by thevohime of gas which must be drawn into the machine per unit time. Saturated .vapor, lat 52.7 psia :has a; specific Volume, from Table 1, of 0.779 cu ft per pound, hence 26.3 X 0.779 = 20..49,.cfm of gas.must be handled. Assuming a volumetric!efficienoy of 90 percent,' the bbrnpressor must'then displace 20:49 + 0.91 -- !22.8 cfm. The speed'is given as 500 rpm and, as the unit is known,to be dquble-acting, tlie.displacemeht isitherefore (22-.8X 1728).+ (2 X 500) = 39.4 cu in:' If the unit were designedso that bore d and,stroke were.the same,..., (vd>) A- 4 = 39.4 wucp) = (A,,!-'Ai,,) +(Ad-`a^)';i d = 3.69 in. ' `s: "s :.'.n; = (82.82 - 29.68) -e (89.34 - 82.82) = 8.17, where h,. is the specific enthalpy of liquid at discharge from the condenser. : The coefficient of performance of Example. 1 may be compared with that of. an ideal system operating on the Carnot cycle between the saxne.tempera? ture limits. Then Ta , ~ 501,F- (wliich is 41 ,F '+ 460) and TV = 554 F (which is 94 F. -|- 460) and, -,u. !;>>!:,! ,i> , : u';-.. ui' : (CP) ' '501 ' ' 554'-501; The .actual cycle is therefore 8.17 + 9.6 dr 85 perediit as effective'as h Carnot cycle between the same temperature limits. ' " - Influence of Suction Pressure Ani.c m,:::,:! . ' Brief consideration of. the analytical procedure: used, in discussion of the simple saturation, cycle.will-hringuout the,need;for.maintaining the suction pressure on. any! refrigeration system! as high as theioa!d will permit. As (he suction , pressure increases, for fixed discharge pressure,: the enthalpy 834 CHAPTER 37 1954 Guide of refrigerant 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 en thalpy of the superheated 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. ' The actual value of suction pressure on any system is obviously de termined by the required temperature which must be maintained in the conditioned space. For a direct expansion 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 es tablish a desired ratio of dehumidifying to cooling load. When dehumidi fication requirements dictate the use of unusually low evaporator :temperatures, the increased operating cost should properly be charged against the dehumidification rather than the sensible cooling. Influence of Discharge Pressure In contrast to the 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 which 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 pressure) raises the enthalpy of the gas leaving the compressor; hence, increases the work of compression. Further, as the enthalpy of saturated liquid leaving the con denser increases with pressure, the refrigerating effect must decreaseThus 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. Influence of Water Jacket The preceding discussion has, in every case, assumed isentropic com pression. 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 occur between the vapor in the cylinder and the cylinder wall, and also 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 aroun the cylinder. Compressor cooling is highly desirable as a method of re ducing power consumption. ' Influence of Superheating and Subcooling . The most common departure from conditions of the simple saturation cycle is that resulting from admission of superheated vapor to the com pressor. Thermodynamically, superheat is undesirable because the e thalpy increase required to compress a vapor through a given pressure rang increases with superheat. Further, superheated vapor leaving an evapo rator is usually an indication that the suction pressure is lower turn1 Refrigeration : 835; necessary. Under practical operating conditions, however, superheat is almost universally used as a means of assuring complete vaporization of the refrigerant going to the compressor. With modem 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 satu ration cycle occurs because of subcooling of refrigerant in the condenser. Thermodynamically, such subcooling 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 con denser 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 sub-cooling cycle than for the saturation cycle. This condition results from the fact that, for the same capacity on a heavily loaded condenser, the refrigerant flow rate is less when there is sub-cooling. Because of the advantages attendant upon the use of sub-cooling, many methods are in use for obtaining some sub-cooling effect outside of the condenser. One common procedure is to use the cold vapor leaving the evaporator to cool the liquid flowing from condenser to expansion valve. Another somewhat unusual sub-cooling 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 Doth sub-cooling of the refrigerant from the condenser and superheating of the refrigerant leaving the evaporator. - Clearance and Volumetric Efficiency Clearance, like displacement, is a characteristic---usually fixed--of a given compressor. In some cases clearance pockets are provided which m Cf w'^'n ^he operator's control the ability to alter the clearance of the B^.but most moderate size compressors are built with fixed clearance. .V definition, the clearance is the percentage of the volume swept by the val n' which is represented by spaces in the end of the cylinder (including Ve spaces, etc.) when the piston is at the end of its stroke. Because of the trapping of high pressure vapor in the clearance space, its subsequent re-expansion, the suction valves of the. compressor 836 CHAPTER 37 .1954. Guide do not'open until the piston has completed,parb.of- its stroke. Hence, the volume of fresh vapor introduced into, the .compressor per stroke is less than the -volume swept; by the piston. The* ratio of actual volume of fresh gas to swept Volume is, by definition, the clearance volumetric effi ciency; CVE. In equation form, be I: (CVE) - 100 - where `'v;'; .= .GVE* clearance volumetric efficiency:' . - Vo = ; clearance; percent of.volume swept by piston, which is contained in spacet ; ' `:,at end'of cylinder when piston is at end of stroke (clearance includes valve spaces, etc.), j.-.'sh'-.Uir- \ /' . : = specific-volume of gas at compressor inlet.: - ' ; r. v : ^ "'specific volume of gas at compressor discharge: . . j; Values of v, and Vd can be obtained directly or by calculation from the tables of properties of refrigerants. ` In addition to clearance, there are several other factors which tend to reduce the volumetric efficiency.,,, The suction gases from the evaporator are heated and expanded upon contact with the hot cylinder walls during the suction stroke. Thisvresults in a reduction of the actual charge drawn into the cylinder. Wire-drawing through the suction and discharge valves reduces the suction pressure in the cylinder below that in the evaporator, and increases the discharge pressure above that in the condenser. Leakage of gases around the pistons also decreases the volumetric efficiency. The total volumetric efficiency (TVE). includes all of these factors and is reliably obtained only by .laboratory measurements... It is too difficult to predict the effects of these factors to any degree of accuracy comparable to actual teStS. ; -. ' . - ... . , ......... Complex Refrigeration Cycles "'r' : ,. The, preceding.sections, have , dealt only with, refrigeration systems in which there is,but ;one evaporator; compression is,accomplished through but,a single stage, and expansion proceeds thro.ugh a single,expansion valve.. In large systems or in low temperature systems in which the compresaon ratio ishigh, the compression'process can be carried .out in stages, with the refrigerant' passing through several cylinders arranged for operation 'in series. .Thp' tliemipdyhamic advantage of such, compound compression arises 'frpm the fact that intercoolers, can .be placed, between the stages (of; compression to extract heat from the vapor, and thereby ckuse the overall compression process to approach more closely the ideal condition of iso thermal compression. Essentially, suchi;intercoplers ,serye the. same .purr, pose as a cooling jacket, but with greater effectiveness because of the more satisfactory heat transfer conditions. - . ... In the simple'saturation cycle the saturated liquid ehteringthe expansion valve'commences to vaporize as soon as'its pressure starts'to drop-. The vapor produced during the expansion process has ri'o further use, , in ternf? of refrigerating effect, since it has already picked up its latent heat of vaporization as a result of heat which it has. extracted from the imvaporized residue. Thus the instant such vapor forms, its usefulness is at an end,' and to allow such material to undergo a further drop in pressure is uneconomical- With `compound compression,' there is at least one intermediate pressure Refrigeration 837 sat. which flash vapor can be .extracted. In such, cases'several expansion valves can be utilized with all ,of the refrigerant from the condenser passed through a first expansion valve to the higher suction pressure,'and, the flash vapor, then extracted and returned to the .condenser through the: high compression stage, , The remaining, refrigerant nan.tben pass through a second expansionvalv.ewhere.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 compressor 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. ,,. The Air Cycle System ............. ................ Fundamentally, the air cycle1 is essentially the same as the vapor cycle. Compression is accomplished-by a reciprocating ipri centrifugal Compressor, and, since there is no change of phase of the refrigerant upon expansion, an air cooler replaces the condenser" and-a refrigerator, the evaporator. Although some cooling would result from the expansion of the gas through an ordinary: expansion valve, a inuch 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 ah expansion engine ;can be utilized- to supply part 'of the work of compression or-to drive other devices. ' . The Steam Jet System ;; " - , :L. The steam, Jet system, under certain circumstances, is desirable for use in air conditioning.2. Steam., slipplies directly. the power used for com pressing the refrigerant,; thus ehminating the losses connected with other methods of supplying energy. 'As1 the compression, ratio: between the evaporator and condenser under normal circumstances is large, the mechan ical efficiency of the equipment is somewhat lower than that of the positive mechanical type compressor. The condensing water requirements are considerably greater, as both the refrigerant and the impelling steam miist he condensed. . .... , .. .... .. ., ........ ?-.... - ... . The,steam jet .system functions, on :the .principle that,waiter-under high vacuum,will, .vaporize at low temperatures.. Steam jet boosters, or;com pressors of the type, commonly used in power plants for various processes, will produce the necessary low absolute pressure to cause evaporation of the water. .... ...... f V A diagrammatic representation of a typical steam ejector water cooling system is shown in Fig. 6. The ..figures, correspond to; an-average .repre sentative system. The water,,to. be copied enters the ..evaporator, and,-is cooled to a temperature corresponding , to, ,the .vacuum, maintained, . Ee- cause 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 theuwater in the .evaporator tank, .this'other water is almost instantly cooled to,a.temperature corresponding; to,the boiling point determined by, the. vacuum maintained.-,. The. amount of water flashed into steam is,a .small percentage,of the. total water, circulated. trough the evaporator, amounting to approximately il IB per (hr) (ton) 838 CHAPTER 37 1954 Guide. 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 evapo rator, plus any entrained air taken from the circulated water, to a some what higher absolute pressure. The vapor and air mix with the impelling steam on the discharge 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 which raises the pressure sufficiently so that the air can be discharged to the atmosphere. A secondary con denser 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 Refrigeration : 839 The Absorption System The absorption and compression refrigeration cycles differ: only with respect to the method of compression. Each cycle requires a condenser, expansion valve, and evaporator, but the absorption cycle utilizes three major equipments in place of the mechanical compressor; these equipments are the absorber, the pump, and the generator. Vapor from the'evaporator is absorbed by a low temperature absorbent fluid which is then pumped to the generator where heat is' supplied to boil off the refrigerant. The ab sorbent is now cooled and readmitted, through a pressure-reducing valve, to the absorber. In addition to the three primary equipments of the absorption cycle it is necessary to provide auxiliary, equipment, usually an analyzer and a rectifier, to remove from the refrigerant leaving the generator, insofar as is possible, the absorbent which vaporizes and leaves the generator with the refrigerant. Removal of this material is of great importance to effec tive operation of the system, since even a small concentration of absorbent &, 801 -M! Fig. 6. Diagrammatic Arrangement of Steam Jet Vacuum Cooling Unit... 5 to 200 psig, and condenser water temperatures as high as 90 P. The steam consumption in pounds per hour per ton of refrigeration increases . rapidly as the booster steam pressure is lowered. For example, the lower ing of the booster steam pressure 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 the steam consump tion 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 evaporator. Usually one booster is automatically controlled, whereas the others are manually operated. The capacity ri 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. . Fig. 7. Closed Absorption System in the refrigerant will suffice to reduce greatly the evaporator pressure required for maintenance of a given evaporator temperature. Thermo dynamic 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 discus sion of various absorbents is given in the sixth book. Thermodynamically, the effectiveness of a refrigerant-absorbent combination increases directly with its negative deviation from Raoult's Law. Fig. 7 shows a typical absorption cycle flow diagram. Cooling water first goes through the absorber (where it extracts the heat of absorption which is liberated by the sefrigerant vapor as it goes into solution), then through tiie 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 rectifier and the warm low concentration solution is returned to CHAPTER 37 the absorber. In the rectifier selective condensation jpcjnijiSjjthepCQn^nf ] tration.of the, absorbent in the condensate being much greater , thanits 5 ebfficeptratioii' iiv.the entering 'vapor mbctiire(rectifier,'condensate is'dripped * back to!the'generator. J. ,J,y^e,^ip.,Qhi;efrigerati'ng effect, to;heat input', (t^p pprfonn^pe rafepi^ commonly..used,'.efficiency measure .of absorption,machines) is..only. 40^to. 45 p.ereept with' the, ordinary ammonia. ,absorptipj))systeffi and, aside from .i --JS ;n,mW in ,fhp use of a toxic, and < " types" oi systems when used'in air conditioning apphcatidng,).,,Therefore)! recently, several absorption .systems using hygroscopic brines ol salts such as lithium1 cliioride or lithium bromide3 (solids in the pure state) as absorb-, ehthand'water JaS the refrigerant have been developed) `1 Such systems are' liinited 'tti higher temperature applicat'iohs but. themiodyhaTnically, have? heat-exchanger (5) .SOLUTION, PUMP U) : PUMP (?) . s ; ; . ... . Fio. 8. Diagram of Lithium Bromide Water Absorption System .. the advantages .of, a refrigerant with a high latent heat of vaporization;'^nSj nonyplatile.absorbents iyith a large negative deviation from Raoiilt's LiW;, Noneidf;tb'e absorbent is carried off with and the performance ratib ranges.as high as 75 per,cent.. Both the refnger-,. . -. ' v xa. . _t--- L.--WAtiitlvni.- nriH nrm-extiiosive and the perfbmiap'te rTahtiips idnoceresa,nseodt;,veaffricyi.egnrecayspiyla;cueesiwotpeurating costs in. competition with ,othert forms of refrigeration in many high temperature applications such as ,air conditioning-.^ . . ".. . One: .form; pf. lithium-bromide-water absorption system is .shown .schea maticaily;in;Ii'ig, 8 with the generator and .condenser, shewn,located ;ifti%' ffigh pressure shell and the evaporator and absqrber in a.lbty'.pfessure.sh^c The water, .to.he cooled. Sows, 'to the; evaporator ,1 '.from theddad wheifoft small portion of it is Sashed into vapor thus cooling the rerriffining wati;.. which is,.then returned.by.pump 2 to the load. The pressure in the. IpJh side shell .and,,therefore, the temperature of. the water passing, through.t-W! shell is controlled by the temperature and concentration of the lithium Refrigeration bromide brine sprayed over absorber coil 3. The water vapor flashed in the evaporator chamber is absorbed by the strong salt solution to form a weak solution which drains from the low pressure chamber and passes through solution pump 4. From pump 4 a portion , of the weak brine is delivered through the heat exchanger 5 to the high pressure shell and the remainder is mixed with the strong solution through eductor 6 and debvered back to the low pressure shell. Heat applied at the generator 7 boils off the water vapor eariier condensed in the absorber and returns the brine to its original concentration. The condenser 8, also located in the high pres sure shell, Uquifies the water boiled off by the generator and this condensate is returned through a liquid loop to the evaporator. The re-concentrated solution is returned from the high pressure shell through the heat exchanger 5 to the eductor 6 where it is mixed with a portion of the weak solution and pumped to the absorber with the mixture at a still relatively high concentra tion. Ice Systems Cold water systems using ice as the cooling agent have been installed in some theaters, restaurants, funeral homes, churches and other places where short hours of operation and high peaks of cooling demand make this type of system desirable. A comparatively small quantity of ice in the water cooling tank of such a system can release refrigeration at a rela tively rapid rate. For instance, neighborhood theaters having a peak demand of 1,200,000 Btu per hr (100 tons refrigeration) have found 8 ton capacity ice bunkers satisfactory. - In operation, the water in the air conditioning system is circulated over ice placed in an insulated box, and is cooled to the 38 or 40 deg range or higher, if desired. This cold water is pumped from the ice bunker to air cooling coils or spray type air washers. The blowers, coils, air washer or air handling sections are the same as those parts in any system employing cold water as a refrigerant. The ice water cooler or ice bunker is usually built at the installation in a location where it can easily be iced. It can be constructed of any de sired material such as concrete, steel, or wood with an adequate amount of insulation to save the ice from one period of use to the next. The basic requirement is that the tank.be durable and water-tight. The temperature of the water is controlled at a predetermined point by a thermostat in the supply line. If the temperature drops too low, a part of the return water is by-passed directly to the sump and is not cooled over the ice. In the larger systems it is customary to install an overflow control which, as the ice melts, discards the excess water through an econo mizer coil, the surface of which is large in relation to the flow so that the water is warmed to 60 F or more as it is discharged from the system. . In an attempt to lower initial equipment cost and operating expense, or increase the refrigeration capacity of an existing air conditioning system, storage refrigeration has been utilized in a few applications. Some of the methods which have been adopted include the storage of refrigeration in the form of chilled water, chilled brine, ice on evaporator coils4 and the accumulation of thin sheets of ice on copper plates in a steel tank.5 If the Peak load factor is low as compared with a long period of operation, such in a restaurant, or if the hours of operation are short but the usage factor mgh, as in a church, then it is possible to consider storage refrigeration, f his method of accumulating refrigeration frequently makes it possible to use low cost off-peak electric power. Power costs may also be reduced by '842 1. H e a t P u m p H e a t 'S o u r c e s A n d S i n k s CHAPTER 37 1954 Guide e. gl 8 5 ,,-8* .a^o ss lllfll a 11=3 2 |-|s-g *l9flfe805-*0S |p8 8*. T3 3 -'?-9 --fe.falj?JS.S 5MOa > . o ,,- ,,- fis-iss'|agg"s1sd .2,, gS fi- .sfgElsssl H put , < > <% O 8ft > t-iliigiS I3 -2C1fiOllElglSlO'> 1 5 w - 3*o-g23s jg0!`aS.2se8l.saO.tj3at*53*3*j3r<t HS cs*t 712! *o & jfil mu: so aa .M 41 W . Uillll . Sg# 2*0 eslp9.g o tct,fe fe JD-O.2 -r3 . I llpllls a- S4g&!rS- S . '< P &S I! 3f ST fcf- I 1| I P<> -1 11 j 0to 3e,, O. -3 "111? a2_a "srla&4sS lsg_8 o< lilgl IMh 1s!s! liilsi Him I| e 1 j 3 a TS 3S 18 a op o D O O3Ja3 s &o o5 <T IS a S 0 & O .s PS ^ B ` - w 1 -1 J5* -- 3 " -o &H 2 M ! JH r3 & VJ2 ?-s 2*2 *.aOSaf ?a !ai 8 If I TO3 o 2O,' *Og s& a a* 8' s.sj %1 * ![P.|1! I8 5- ^SS.-gaS a a .o 2 P _. >. 3 3 &3 -S5 HSM B o*j ? fl ons.p fc,##I;.g-SE o iS ga "pH C#' ' SS5 TS-8 3s: Ip & I 1 ah ~44 , 44 J|QJtsi ll!lil| "agS3g*{jo.a`"5tSSa.bgls.B*gEo.g''fS!3l!S-o3>. 1Sb13O > .* 5S *g si o a* ,6 2.2 >* S"o s i% 3 _ g l! .5- I Is U* fr. w ga Is a* O'-rss .JS>8a3^S2 llpiil eooo < < aa ,o 3 3.l| Bf S|a &b o cs Id its H HO 8o %I sl%S i-St aa- Refrigeration 843 installing a smaller refrigeration plant, augmented by a storage system, and by operating it for longer periods. The Heat Pump It has been almost 100 years since Prof. William Thomson (Lord Kelvin) first proposed the use of a compressor as a "wanning engine" and as a means of heating buildings to replace equipment for direct burning of fuels. Several early working models were constructed, but the device has remained essen tially of laboratory interest until the last 20 years. Although frequently referred to incorrectly as the reverse cycle system, the heat pump cycle is identical with the ordinary refrigeration cyole, and differs only in the sense that the desired effect is rejection of the heat from the condenser rather than absorption of heat in the evaporator. A discus sion of the coefficient of performance for the heat pump is found earlier in this chapter. . The first actual residential heat pump installation was probably made in Scotland in 1927 and since that time, a number of commercial and residen tial systems have been made in this country. Both progress and growth of interest have been particularly rapid in recent years and, consequently, at the present time there are several hundred residential installations and probably a greater'number of commercial systems. However, much re search is needed before the residential heat pump installation can success fully emerge to compete economically and with equal reliability with the more common forms of heating and fuels. From an analysis of the equation for the coefficient of performance, it is evident that the economical adaption of the heat pump as a practical means of heating, requires that the temperature of the source from which the heat is extracted be as high as possible, and that the temperature of the sink to which the heat is rejected for heating purposes, be as low as possible. Thus, with a small temperature spread between the evaporator and the con denser, six or more times as much heat may be obtained theoretically (and three to five times practically) as the heat equivalent of the work necessary to operate the system. There are a number of limitations, however, the most serious of which is the lack of ready availability of a practical source of heat. One of the major problems in the development of the heat pump involves research on, and the compilation of reliable design data for, the various heat sources and sinks available. The four principal potential sources of heat are air, water, earth, and solar energy. Of these, the first three are primary sources of heat which may be used alone! The fourth, solar energy, while of tremendous potentiality, will probably be developed in most localities as auxiliary to the other three. In addition, there are other minor sources such as process waste heat, sewage, etc., which may he used under special circumstance. There are also a number of industrial applications of heat pumps, for purposes other than space heating, which are practical largely through economic considerations of the particular process involved. Table 4 pre sents a summary of the advantages and disadvantages of each of these major heat sources. By reference to Table 4, it will be seen that, to date, the most satisfactory heat sources are air, water, and earth, and that air and water are the most satisfactory heat sinks. There are, therefore, six possible combinations of source and sink in application: air to air, air to water, water to air, water 10 water, earth to air, and earth to water. In addition, it should be recog- 844 CHAPTER 37 1954 Guide nized that, heat storage devices may be used with any of these systems involving either a single or a dual heat source. One promising possibility involves the utilization of a storage pit or cistern operating upon a heat of fusion cycle and supplied by supplementary heat from air or solar sources. Heat of fusion may, for example, also be utilized with city water and sewage disposal to increase the practicability of these sources. When heat is to be obtained from a ground coil it should be emphasized that, in general, the heat extracted must be replaced by heat from the sun, received by radiation to the ground or by heat carried into the ground by rain. . Combinations of heat sources, such as air and water, air and ground, air and solar energy, or ground and solar energy, may also be used and will frequently improve the coefficient of performance over an entire heating season; but they will probably result in considerably greater initial cost. A typical arrangement of a heat pump system with air as the heat source is shown in Fig. 9. Both water and air are practical media to which the condenser heat may be rejected; but the generation of steam requires too high a condenser temperature. Practical operation, therefore, dictates that the heat pump be used in conjunction with either an air or water heating system with actual distribution of the heat to the rooms through either air ducts, convection radiators, or panels. In general, it is believed that the future of this device is very promising, and it is recognized that there are a number of practical and economical systems in operation at the present time. However, design data for the majority of types of systems are inadequate, and it is therefore recom mended that the enthusiasm and the interest which have greeted the emergence of the heat pump from the category of a scientific toy to one . of practical application, should be tempered with caution, since it will probably be several years before proper development and design in formation will enable the widespread satisfactory application of the heat pump. It is for this reason that no design information is presented at this time in The Guide. A wealth of literature concerning individual installa tions is available, and reference to the many articles which have appeared Refrigeration 845 in current technical magazines should form sufficient information for those interested in the development of this type of heating. _ BASIC REFRIGERATION EQUIPMENT Compression Refrigeration Machines Compression of the refrigerant gas drawn from the evaporator may be accomplished by one of several means. Positive displacement may be used as in the reciprocating, rotary or gear types of compressors; centrif ugal force may be applied as in tide 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 reciprocating compressors, rotary compressors and centrifugal compressors. Reciprocating Compressors . , Reciprocating compressors may be classified according to (a) cylinder design, (b) compressor drive, (c) valves, and (d) lubrication and cooling. Cylinder Design. Cylinder design may vary as to number, arrangement, and action (.., single-acting or double-acting). Single-acting compressors usually have their cylinders arranged vertically, radially, or in a V or W shaped arrangement. Double-acting compressors, with refrigerant gas drawn in, and compressed on both the head and crank ends of the cylinder, are usually arranged horizontally. Re ciprocating units are available with from one to sixteen cylinders with the V, W, or . radial arrangements best adapted to the greatest numbers. 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 com pressors were slow speed (50 to 55 rpm) steam driven devices, modern electric motordriven 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 com pression or of foreign materials entering the compressor 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 subdivided on the basis of source of motive power, and whether they are open or hermetic. Practically all , modern 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. In a few cases, as with truck transportation, the compressor may be driven by an internal-combustion engine. 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 received from an external source with one end of the compressor crankshaft extending through the crankcase, and usually V-belt driven. The point of emergence of the shaft from the crankcase forms a weak point of refrigerant leakage, and is most frequently Bealed with a bellows type crankshaft seal. Horizontal double-acting compressors operate with a sliding piston rod, moving back and forth through a stuffing box. If the motor js direct-drive and enclosed within the compressor housing, the compressor is classi- "ed as closed or hermetic. This eliminates the necessity of any shaft seal, and not 5P*y prevents refrigerant leakage at this point, but reduces operating noise. One disadvantage is the inaccessibility of moving parts for repairs, but lubrication is greatly simplified since both the motor and compressor operate in a sealed space with "e lubricating oil. ' Compressor Valves. All refrigeration compressor valves are dependent for their 846 CHAPTER 37 1954 Guide A operation upon a difference in pressure between the inside of the cylinder and the suction or discharge line. Although mechanically-operated valves might have some advantage, they have proved unsatisfactory because each change in tne 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 arrangement). The valves themselves are usually classified as either poppet, ring-plate or flexing. Lubrication and Cooling. Lubrication of modern compressors is accomplished by either splash lubrication or forced lubrication. The latter is used on large com pressors, 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 com pressors are either water cooled or air cooled with extended finned surfaces cast on Refrigeration 847 Centrifugal Compressors Centrifugal compressors are used with very low pressure refrigerants; usually both evaporator and condenser work below atmospheric pressure. Water and monofluorotriehloTomethane (F-ll) are the refrigerants com monly used in centrifugal machines. Compression of the refrigerant is accomplished by means of centrifugal force; therefore, this type of compressor is inherently suitable for laige volumes of refrigerant at low pressure differentials. Two or more stages are usually required and high speeds are necessary to obtain good efficiency. The evaporator is usually constructed as an integral part of the centrif ugal type condensing unit, to chill water which is then circulated to the' Fig. 10. Diagrammatic View op Rotary Compressor with Flooded Evaporator and Capillary Tube the exterior of the cylinder. In a few cases small compressors 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 condi tions 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. Rotary Compressors In recent years rotary compressors, usually hermetically sealed, have become quite popular for fractional tonnage applications and are being designed in increasingly larger sizes. Of the various designs attempted, the single blade rotary compressor, shown diagrammatically in Fig. 10, is the most popular. An eccentric driven rotor revolves within a housing in which the suction and discharge passages are separated by means of a sealing blade. When the rotating eccentric first passes this blade and the suction opening, the compressor suction space is veiy small. As the ec centric rotates, this crescent-shaped space becomes increasingly larger, thereby drawing in a charge of suction gas. When the eccentric again passes the blade, the gas charge is cut off from the suction inlet, compressed, and discharged from the compressor. Such rotary compressors are quiet in operation and reasonably free from vibration. In common with other types of hermetically sealed units, they have the advantages of compara tively low loss of refrigerant and sealed-in lubrication. Fig. 11. Enclosed Type Centrifugal Condensing Unit wuiuoiumiig i- ms lb uone Decause it uvum * to pipe these large volumes of refrigerant any distance. Centrifugal compressors, like reciprocating compressors, can be divided into two general types, open and enclosed. In general, the open type com pressor is geared to the driving mechanism, and operates at higher speed than the driving motor or turbine. A modem, completely enclosed, directdriven centrifugal compressor is illustrated in Fig. 11. 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 ir units 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 is also possible to secure units as low as 50 tons in rating. Because cen trifugal units operate best with refrigerants possessing a high specific vol ume, and because of the simplification 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 im ' Portant advantage is their flexibility under varying loads, since units may be 848 CHAPTER 37 1954 Guide designed to operate with reasonable efficiency at capacities as low as 20 per cent of normal load. Condensers Condensers used for liquefying the refrigerant are of three general de signs: (1) air cooled, (2) water cooled, and (3) evaporative (combination air and water). 1. Air cooled condensers are seldom used for capacities above 3 tons of refrigeration, unless an adequate water supply is extremely difficult to obtain, as, for instance, in railway air conditioning. Even on fractional tonnage installations, air is used as the condensing medium only where water is expensive, or where simplicity of instal lation warrants the higher condensing pressure and consequent power costs higher than would be obtained using water as the condensing medium. The conventional air cooled condenser consists of an extended 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 con densers should always be located in a well ventilated space so that the heated air may escape and be replaced by cooled air. The principal disadvantages of air cooled condensers are the power required to move the air, and the reduction of capacity on hot days. This loss of capacity, due to high condensing pressures on hot. days, requires that equipment of increased capacity be selected to meet the peak load. Thus at normal loads the equipment is oversized. The principal advantages are low installation costs and simplicity, and for these reasons they are frequently used in small self-contained units. 2. Water cooled condensers are commonly used with compressors of one horsepower or larger in size, and they are found almost exclusively on large installations. They usually prove to be the most economical choice if an adequate water supply and means for its disposal are available. Although water-cooled condensers may be of many designs, the shell and coil and the shell and tube are most commonly found in present day practice. The amount and temperature of the condensing water determine 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. Because there is a decided tendency to conserve the water in city mains, and because most large cities are restricting the use of water for air conditioning and refrigeration equipment, it is often necessary to install cooling towers or evaporative condensers. Cooling towers, unfortunately, produce the warmest condensing water at the time when the load on the system is greatest, so that the refrigeration equip ment must be designed to meet the maximum load at abnormal condensing water temperatures. If properly designed, this makes little difference in the efficiency of operation throughout the year, except at those times when the condensing water temperature is highest. As this occurs only for 5 percent of the entire cooling period, it can be disregarded as a factor in establishing yearly operating costs. For further information on cooling towers, reference may be made to Chapter. 35. 3. Evaporalive condensers were developed to alleviate: the over-burdened water supply and drainage facilities of communities where many small air conditioning; systems using water cooled condensers were applied. The adaptation of cooling, towers to small installations is not practicable. The evaporative condenser combines: the functions of the two by using a minimum amount of water on a finned surface, cooling it to approximately the wet-bulb temperature of the surrounding atmos phere r : The end view of a typical evaporative condenser is shown in Fig. 12. The fan draws the air over a finned tube condenser which is kept wet by a water spray. The: discharge refrigerant gas from the compressor enters the top of the condenser cod' and the liquid refrigerant is drained from the bottom of the coil into a liquid receiver, and then circulates through the remaining portion of the system in the usual way- The water is circulated through the spray nozzles, and the level is maintained in the sump by means of a float valve. The eliminator plates are placed in the path of. Refrigeration 849 the water-air mixture so as to remove the entrained: water. The air leaving:the unit is almost completely saturated, so that care must be taken in locating discharge ducts to prevent condensation. Evaporative condensers are available in sizes up to .100 tons or <more... These units use only a small portion of the water required for a water cooled Condenser. The water iB vaporized by the heat of the refrigerant so that each pound Of water used extracts approximately 1000 Btu from the refrigerant, whereas under standard rating conditions where the water temperature rise is 20 F, each pound of water extracts only 20 Btu from the refrigerant. Including the water lost by entrainment Fig. 12. Schematic View op an Evaporative Condenser in the discharge air, by overflow and stand-by evaporation, the water used is about 3 to 5.percent of the amount that 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 has a higher first cost than the water cooled condenser, but where the use of water is restricted or expensive, the evapora tive condenser has become widely accepted. Compared with a water_ cooled con denser and cooling tower, which combination uses about the same quantity of water, the evaporative condenser has the advantage of lower cost and smaller space re quirements. - "` 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 850 CHAPTER 37 1954 Guide evaporation with the vapors leaving slightly superheated. In flooded evaporators not all of the refrigerant is evaporated, the liquid-vapor mix ture 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 conditioning work fall 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 absorber where the water flows over direct expansion coils at a rate sufficiently high to give efficient heat 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 transfer, and as the refrigerant is in the shell completely surrounding 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 tempera ture 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 re frigerant to escape into the water passage. This danger can be eliminated by auto matic 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 con duction 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 requirement than the smooth coil. The fins, however, must be far enough apart so as not to retain the moisture which condenses 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 tbe air forced across the coil and dis charged through distributing ducts or directly into the space to be conditioned. Unit coolers, designed much like unit beaters, consist of a finned coil, propeller fan, and controls suspended directly in the space to be cooled. 3. Indirect brine coolers. The indirect cooler, where brine is cooled by the re frigerant and the resulting cold brine is used to cool either air or water, introduces several other considerations. It is not the most economical from a power consump tion standpoint, as it is necessary to cool the brine to a temperature sufficiently low so that there is an appreciable difference between the average brine temperature and that of the substance being cooled. This requires that the temperature of the refrigerant 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 conditioning equipment. This arrangement eliminates any possibility of direct contact between the air and refrigerant. REFRIGERATION CONTROL In addition to the compressor, evaporator, and condenser, several auxili aries are required for proper operation of a refrigeration system. Some device must be supplied for the controlled expansion of the refrigerant from Refrigeration 851 the high condenser pressure to the low evaporator pressure; controls are required for the on-off operation of the compressor, the flow of the con densing medium, and for safety devices; proper piping is required for connecting the various portions of the systems. Where refrigerating appa ratus is used for the cooling of rooms, additional controls are required. Expansion Devices Some form of expansion device must be provided to control the rate of flow of the liquid refrigerant between the high and low side pressures of the system. This device is usually an expansion valve and may be either manual or automatic; however, with few exceptions, manual valves are obsolete and no longer used. Automatic Expansion Valves. An automatic or pressure controlled expansion valve operates to maintain a constant pressure in the evaporator. The liquid re frigerant passes 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 adjustable spring, balanced against the bellows, and these two forces operate to maintain a constant pressure in the evaporator 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 fluctuating loads such as are encountered in air conditioning installations. Thermostatic Expansion Valves. A thermostatic expansion valve controls the flow of liquid refrigerant to the evaporator so as to maintain the entire coil filled with evaporating refrigerant, and to keep a constant superheat in the refrigerant gas leaving the coil. The construction of such a valve is shown in Fig. 13 and is similar 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 connected by means of a capillary tube to a feeler bulb fastened to the suction line 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 evaporator results in a greater superheat in the gas leaving the evaporator, and this in turn operates through the power element to increase the flow of liquid refrigerant. A flooded evaporator reduces the discharge superheat, and thus tends to reduce the flow of liquid rejngerant. Such an expansion valve is satisfactory for operation with fluctuating loads since this type of control tends to keep the evaporator filled with refrigerant at all times. Low-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 852 CHAPTER 37 1954 Guide the low pressure side of the system. A needle valve, operated through a simple lever mechanism attached to the float, permits the passage of more or less refrigerant, as the level in the receiver or the evaporator fluctuates. Such a control must be used in conjunction with a flooded evaporator, and has been applied extensively to household refrigerators and, to some extent, in commercial and industrial instal lations. High-Side Float Voices. 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 con tainer. 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 Tubes. 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 diameter) of five to twenty feet in length. Although such a restricting device operates as a very simple means of expanding the liquid refrigerant, it has the disadvantage that no modifications 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 factory assembled domestic and commercial units. Refrigeration Control Devices In addition to automatic control of expansion of the liquid refrigerant, a completely automatic refrigeration system requires (1) some means for on-off operation of the compressor motor, (2) control of the flow of the con densing medium, and (3) safety devices for prevention of damage to the equipment. In addition, special controls designed for specific applications are frequently required. The various types of devices used to accomplish these purposes are so numerous that it would be impossible to describe all of their modifications. . Only the general purposes and operating char acteristics of the more typical mechanisms are here discussed. Compressor Motor Controls. Two types of controls are used for intermittently starting and stopping compressors. The first of these is a pressure motor control responsive to the evaporator pressure, and the second a thermostatic motor control responsive to the temperature of the load surrounding the evaporators. In the first case the compressor operation is indirectly dependent upon the temperature of the load, and is controlled by the refrigerant pressure at the point of control location. The second type is dependent upon the temperature of the load being cooled. . With the pressure actuated device, the control is frequently located directly on the condensing unit, and the low pressure in the suction line or the crankcase of the compressor is used to control motor operation. Such a control usually consists of a low pressure bellows, connected through tubing directly to the low pressure control source, and an electrical switch operated through linkage by the movement of the bellows. The electrical circuit is closed on rising pressure, and opened on falling pressure. The thermostatic type of motor control is usually similar in construction to the pressure control, with the exception that a temperature bulb and capillary tube replace the pressure line, and the temperature bulb is located adjacent to the evaporator itself. In this case motor control is directlyresponsive to changes in the temperature of the load surrounding the evaporator. Frequently, a high pressure safety cutout switch is combined with the motor control, and operates to cut off the power from the motor in case the high side pressure exceeds a predetermined limit; Solenoid Valves. Solenoid or magnetic stop valves are frequently used in re frigeration Bystems for control of gas and liquid flow. When applied as liquid stop valves, they are placed in the liquid line between the condenser or receiver and the evaporator, and the line is open to passage of the refrigerant only when the com pressor is in operation. When the compressor is not in operation, leakage of liquid refrigerant in the evaporator is prevented. In some cases such a magnetic stop valve is operated directly by a thermostat located at the point of the load, and the compressor motor operation is controlled independently by a low pressure switch.' Refrigeration 853 Magnetic liquid stop valves are also widely used for the control of the refrigerant flow to individual evaporators in a multiple evaporator system operated by one compressor. In some installations magnetic liquid line and suction line valves arc used to isolate completely an evaporator for defrosting purposes. A magnetic valve may be installed in a by-pass around one or more cylinders of a multiple cylinder compressor, and thereby be used to unload a compressor during starting to reduce load. Additional applications are found in control of the circulation of brine in a secondary refrigeration system. Suction Pressure Valves. Suction pressure control valves, frequently called back pressure regulators or two-temperature valves, are sometimes placed in the suction line to prevent the evaporator pressure and temperature from dropping below a pre determined level. Typical applications of such controls occur in water cooling or milk cooling systems, where freezing and other damage would result if the evaporator pressure dropped too low, or in multiple systems where several evaporators are supplied by one condensing unit. Thus, different evaporators may be kept at different temperatures by maintaining a pressure drop between the evaporator and the suction line. Condensing Water Control. The majority of the refrigeration systems, other than fractional horsepower, use water cooled rather than air cooled condensers, since the lower condensing temperatures result in more economical operation. Automatic control of the water flow to the condenser must be maintained if water wastage is to be eliminated. Such control may be provided through the use of either an electric solenoid water valve or by means of a pressure control valve. With a solenoid valve, . the flow is two-position, either off or on, and its operation is simultaneous with starting and stopping of the compressor motor. With a pressure operated valve, the flow is modulated and is dependent entirely upon condenser pressure rather than condensing unit operation. Similar water valves controlled thermostatically by the temperature of the water discharged from the condenser are also available. Safely Controls. Many controls are designed not to aid in proper operation of the system, but to prevent damage in case of improper operation. One such safety control is the high-pressure cutoff frequently combined with the low-pressure motor control as previously described. Another safety control often used is a low voltage cut-off which shuts down the system automatically in case the line voltage drops below a minimum value. High pressure relief valves are used for safety purposes to prevent damage in caBe excessive condensing pressures are encountered. Refrigeration Control for Air Conditioning Equipment When refrigerating equipment is used for space cooling, two major control problems exist:.one is control of the temperature and the 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 re wanned to return it to the comfort range. Chapter 39, Automatic Control, discusses, among other topics, control systems for unit coolers, well water and ice cooling systems, central fan systems, and all-year 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. The pressure drop through the connectlng piping between the compressor and the condenser requires that a higher pressure be maintained inside the compressor during discharge than in the 854 CHAPTER 37 1954 Guide condenser. These losses result in a greater compression ratio, and therefore greater power requirements, as well , as a lower volumetric efficiency and higher displacement requirements. Pressure losses in the liquid line between condenser or receiver and the expansion valve may result in some flashing of the liquid refrigerant, unless the liquid is subcooled. In all cases, frictional 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 be preferably 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 refriger ant ahead of the expansion valve. If the evaporator is to be located at a higher elevation than the condenser or receiver, account should be taken Table 5. Fbeon-12 Liquid Lines, Tons Capacity per 100 Ft Equivalent Length Line Sue, Inches Pressure Drop per 100 Ft Equivalent Length, Psi .3 . 5 10 20 1 OD \ OD i IPS f OD i IPS f OD 1 IPS H OD 11 IPS 1| OD HIPS If OD 2 IPS 21 IPS 3 IPS 31 IPS 4 IPS 0.88 2.89 4.86 4.86 9.73 10.5 21.4 21.4 36.9 36.9 62.0 62.0 124. 230. 364. 539. 753. 1.14 3.64 6.81 6.81 12.6 14.1 28.2 28.2 48.1 48.1 80.2 80.2 161. 297. 469. 704. 972. . 1.80 5.56 10.2 10.2 18.5 21.8 41.3 41.3 70.5 70.5 114. 114. 231. 426. 676. 1005. 1385. 2.58 8.50 15.8 15.8 27.0 33.0 60.8 60.8 101. 101. 160. 160. 328. 607. 972. 1430. 1945. Note: Tonnage values above those underlined give velocities of 300 fpm or less. 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 Freon-12, 0.51 psi per foot for Freon-22, and 0.64 psi per foot for Freon-11. Where there is a possibility of vaporization of some of the liquid before reaching the ex-; pansion 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 refrigera tion, great care should be giveD to the proper sizing of suction lines between the evaporator and the compressor. Although comparatively high veloci ties, 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 Freon and methyl chloride, for these refrigerants the minimum velocity should be 500 fp for horizontal runs and 1000 fpm for vertical runs. For the Freons, the usual design velocities range between 1000 and 2000 fpm. Too high velocities create noise problems and excessive pressure drops. t The total Refrigeration 855 Table 6. Maximum Tons of CoMP^sson.CAPACiTY tor Fbeon-12 Lines Line Size ' ' Inches i OD 1 IPS |OD \ IPS i OD f IPS H OD 1 IPS H OD li IPS If OD H IPS 2J OD 2 IPS 2f OD 2f IPS 3f OD 3 IPS 3f OD . 3| IPS 4f OD 4 IPS 5 IPS 6 IPS 8 IPS 10 IPS 12 IPS Suction Lines .Based on 105 F Condensing Temperature ' Discharge Lines Psi Pressure Drop per 100 Ft Equivalent Length at 40 F Saturation Condensing Temperature i 0.11 0.17 0.25 0.35 1 0.2( 0.21 0.3 0.45 2 0.2S 0.31 0.51 0.65 3 0.35 0.45 0.65 0.7E 4 0.41 0.4S 0.7: 0.93 5 0.45 0.5 0.81 1.03 115 F 1.43 1.81 90 F 1.15 1.50 0.55 0.68 1.26 1.43 0.76 ' 0.94 1.80 2.01 1.10 1.35 2.57 2.89 1.31 1.65 3.17 3.54 1.5S .1.95 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 2.21 2.70 3.40 4.05 3.12 3.82 4.78 5,75 4.45 5.50 5.37 6.72 6.79 8.42 8.10 10.12 6.38 7.68 9.77 11.6 7.05 8.48 10.8 12.8 7.72 9.16 10.92 12.5 6.19 7.35 8.75 10.0 6.12 7.66 12.0 12.0 8.60 10.9 17.1 17.1 12.1 15.3 24.0 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 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 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 2C3 366 123 130 224 403 95.8 101.6 171.5 266 77.1 81.6 137.8 214 211 352 550 297 503 780 422 712 1106 523 887 1373 602 1024 1582 664 1130 1748 461 725 1041 370 582 836 pressure velocity drop in the suction line should be between can be kept to within the specified limits. one and two psi, if the 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-1946, of the AtrConditioning and Refrigeration Institute, and are used by permission. Table 7. Approximate Suction-line Capacity Factors for Equal Pressure .___________ Saturated Suction Temperature, F. factor Drop of Freon-12 50 40 30 20 10 0 -10 -20 1.09 1.00 0.92 0.86 0.80 0.74 0.66 0.56 856 CHAPTER 37 1954<luide Table 5 shows the tonnage, capacity normally allowed for Freon-12 liquid lines per foot equivalent length of pipe, and Table 6 the ifaaximum tonnage for suction and discharge Freon-12 lines. Table 7 presents suc tion-line capacity factors for equal pressure drop. ACCESSORIES Dehydrators, oil separators, strainers, vibration eliminators, sight glasses, and various types of valves are accessories frequently needed for the proper Refrigeration 857 in water lines-leading to water cooled condensers,-: Sight glasses which permit visual inspection of the condition qf the refrigerant are sometimes installed on factory assembled commercial unit systems.- This particularly advisable to place such a fitting before the expansion valve, if the evaporator is located above the condenser. " : ;i x Flexible vibration eliminators, usually consisting of. a .bellows', design covered with woven copper wire, are sometimes ,installed in copper-lines where unite such as. compressors are installed on, flexible, mountings, or where vibration is otherwise a problem. Packed or packless shut-off valves are necessary where it may be required to'ikdate portions of a'system,' Fig. 14. Performance Characteristics of Compression Refrigeration Machines at Constant Speed 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, acti vated 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 compressor crankcase and its passage^0into the condenser and evaporator. The oil is separated from the gaseous; refrigerant by gravity during its passage through a chamber of sufficient \ size to reduce the velocity. A float-operated valve maintains a maximum; oil level in the separator, and additional 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 exDansion valves, as well as before regulating valves*;. ... _____.i. ' * 85 90 95 100 105 110 CONDENSER TEMPERATURE. DEG FAHR ' Pig. 15. Performance Characteristics of Compression Refrigeration Machines at Constant Speed EQUIPMENT CHARACTERISTICS AND SELECTION The various types of compression systems have quite different charac teristics of capacity and . power with varying evaporator and condenser temperatures, as may be noted from curves in Figs;,14 and 15. : From Fig. 14 it may be observed that power requirements for the centrif ugal compressor increase much more rapidly than for the reciprocating cmpressor, with increase in evaporator temperature. Similarly, the ca pacities of the steam ejector and centrifugal compressors increase, more tepidly than those of the reciprocating compressor with' increase in evapo- tetor temperature. . Thus, both the steam jet and centrifugal machines tend to be more self-regulating than the reciprocating. It isalsq evident ffb-n pjg that the steam jet equipment is best suited for operation at u>gh evaporator temperatures. . ., th^!n e^ec* of. condenser temperature upon the power and capacity of e different types of compressors is shown in Fig. 15. It may be noted ;[: i ' I|- : :|f 858 CHAPTER 37 1954 Guide) .5 "vsSS that the power required by the reciprocating compressor increases rapidlyRf with increase in condenser temperature, while the power curve for: the centrifugal compressor is relatively flat. It is also evident that the. ca^ pacity 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 others 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" Table 8. Basis of Equipment Selection Capacity Tons 0 to'5 5 to 25 Majority Used Some Used. Few Used Unit systems in con ditioned space. Unit central systems using duct distri Built up central sys tems. bution. . Built up central sys Unit central systems tems using recipro using duct distri cating compres-. bution. sors. Unit systems in con ditioned space. Built up systems us: ing absorption andc adsorption sys tems. . 25 to 50 Built up central sys tems using recipro cating compres1 sors. . Built up central systerns using centrif ugal compressors. Central systems us-, ing adsorption sys; terns. "` 50 to 400 Built up central sys tems using recipro cating compresr sors. Built up central sys tems using steam . jet and centrifugal compressors. Built up central sys Built up central sys 400 and Over tems using centrif tems using, steam ugal compressors.! jet. :. job is of utmost importance for satisfactory results. The most important factors in the selection of the equipment are: - 1. LoadB (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 influence the type of sysfe to be used). A broad division of equipment to be used for a particular instfillatiotf'or application may be made on the basis of the magnitude of the load. ' Cur: rent general practice is outlined in Table 8. . Unit or packaged systems, consisting of a reciprocating compress condenser, evaporator, and fans, are generally used in the smaller size jobs where electric power is available, as they are manufactured complete/ ready to install, and are the most economical (see Chapter 26). The reciprocating compressor in the built-up central system (* Refrigeration 859 Chapter 30) covers the widest range of application since it is applicable to either the direct expansion or indirect systems, and can be driven by steam or gas engines, 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. Centrifugal compressors are used for large installations, and usually where the indirect system is required. The driving mechanism 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. 14 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 05 6 <9 Z </) z 8 Fig. 16. Compressor and Coil Performance produce a given result, but the performance can be predicted under vary ing load conditions by the simple expedient of using the variable of evapo rating temperature as the abscissa, and the load or capacity as the ordinate m a series of curves. Manufacturers of compressors and cooling coils furnish performance data for apparatus that can be plotted in the form of curves similar to those shown in Fig. 16. The performance 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 18 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 the 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 2 percent sensible to total heat, the operating point A in Fig. 16 is found |o be 42.2 F evaporating temperature, with a face velocity of 500 fpm. In the case of the restaurant, with a ratio of 69.5 percent sensible to total heat, the air velocity is lowered to 300 fpm, and the evaporating tempera- 860 CHAPTER 37 1954 Guide :'4 Table. 9. Typical Operating Conditions for Two Types of Load Type of Enclosure . Load, Btu peb-Houb '' Sensible Latent Total. Ratio Sen sible TO Total Air Entering Operating Balance Point ' Coil F Deg . Per Cent R.H. Evapo rator Temp F Deg Con-. denser Per Cent Pressure Sensible Lb per Heat 8q In. Restaurant.... 103,000 45,000 148,000 0.695 82. 45 34.4 123 69.9 121,000 27,000 148,000 0.820 82 45 42.2 100 82.1 ture is loweredto 34.4 F as shown in points of Fig. 16. 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. L ... REFERENCES ; , - , 1 Air Cycle Refrigeration, by Paul- C . Scofield (Refrigerating Engineering, Vol. 57, No. 6, June 1949; p: 558). ~ ...... . - 1 Application and Economy of Steam Jet Refrigeration to Air Conditioning, by( A. R. Mumford and A. A. Markson (A.S.H.VE. Transactions; Vol. 44,1938, p. 33);* A New Development in Absorption Refrigeration; by A: A. Berestneff (Be- frigerating Engineering, Vol. 57, No. 6, June 1949, p. 553). . 4 The Application of Storage Refrigeration to Air.Conditioning, by C. F. Booster^.' (A.S'.H.V.E. Transactions, Vol. 45, 1939, p. 675); /' "t" 4 Use of Cold Accumulators in the Air- Conditioning Field, by R. W. Evans and;-; C. J. Otterholm (A.S.H.V.E. Transactions, Vol. 48/1942, p.T23). ;; BIBLIOGRAPHY " - Refrigerating Data Book, Vol. 1 (American Society of Refrigerating Engineers). .. Refrigeration Engineering, by H. J. Macintire (John Wiley & Sons). Theory of Mechanical Refrigeration, by. N. R. Sparks (McGraw-Hill Book Co.)-' Refrigeration and Air Conditioning Engineering, by B. F. Raber and F. W. Hutchinson (John Wiley & Sons, 1945). Refrigeration, by J. A. Moyer and R. U. Fittz (McGraw-Hill Book Co.). 1^. Refrigerants and Absorbents, by W: R.HainswOrth (.Refrigerating Engineering).f August and September, 1944). ; i' f,i.- Air Conditioning and Refrigeration, by B. H. Jennings and S. R. Lewis (Intej;-., national Textbook Company, 1944). Refrigeration and Air Conditioning, by Jordan and Priester (Prentice-Hall, Inc.,;. 1948). ;nb.; Heal Pumps, by P. Sporn, E. R. Ambrose and T. Baumeister (John Wiley, aid C Sons, 1947). : ... . ; - Heat Pump Applications, by E. N. Kemler and S. Oglesby. Jr. (McGraw Hill Book Co., 1950). . . . ?|: CHAPTER .38 DEHUMIDIFICATION BY SORBENT MATERIALS Definitions and Principles, Adsorbents, Dehumidification by Solid Adsorbents,, Dehumidification Equipment Using Solid Adsorbents, Absorbents, Dehumidification by Liquid Absorbents, Dehumidification Equipment Using Liquid Absorbents, Calculation of Moisture Load, Vapor Transfer to Dehumidified Space DEHUMIDIFICATION as used herein, is the reduction of the water vapor content of a given volume of air or other gas. The term thus describes a special case of dehydration which covers the removal of moisture in any form from matter. The degree of dehumidification required varies greatly with different applications, and is one of the prime considerations influencing the choice of a method. Dehumidifieation may be accom plished by latent heat removal, together with sensible heat removal, as described in Chapters 30, 35, and 36, or by the use of, sorbents. Sorbents are substances which have the property of extracting and hold ing other substances (usually gases or vapors, e.g., water vapor), brought into contact with them. All materials are sorbents to a greater or lesser degree. The weight of water held by a substance will increase or decrease, depending upon whether the vapor pressure of the water held by the sub stance is less or greater, respectively, than the partial pressure of water vapor in the surrounding atmosphere. As generally used, however, 'the term sorbents refers to those materials having a,capacity for moisture which is large compared to their volume and weight. : Such materials are divided into two general classifications: 1. Adsorbent--A sorbent which does not change physically or chemically during the sorption process. Certain solid materials, such as activated alumina, silica gel, activated bauxites, and activated charcoal have this property. The action of adsorb ents, 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, Bilica gel would remove the water vapor in preference to the organic vapors, 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 con taminating vapors from an air or gas mixture. (See Chapter 8.) ' '. 2. Absorbent--A sorbent which changes either physically, chemically, or both; duringthe sorption process. Calcium chloride is an example of a solid absorbent, while liquid absorbents include solutions of lithium chloride, calcium chloride, lith ium bromide, and the ethylene glycols. The ability of an adsorbent 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 reactivated condition) is less than the partial pressure of-the water vapor in the surrounding atmosphere. For instance, when an active ad sorbent 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 equi librium with the partial pressure of the water in the surrounding gas, with 861 862 CHAPTER 38 1954 GuidePi, -teS. the result that water is extracted by the adsorbent and its weight increased "S'.;, 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 dependentA* upon the relative humidity (ratio of the partial pressure in the gas to the f/ saturation pressure at a given temperature) and the temperature of theft; 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 the vapor in the surrounding atmosphere, water ., will be released by the adsorbent. After the adsorbent cools to room tern-.; perature, for instance, the vapor pressure of the water in the adsorbent falls: > below the partial pressure of the vapor in the atmosphere, 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 ad:0 sorbent so that it may be used repeatedly. J. ?; Adsorption is proportional to the amount of surface (internal and exter nal) of the sorbent. The materials that are used commercially as solid ; adsorbents have a porous structure of sub-microscopic dimensions, which' gives them extensive surface area. An adsorbent should meet the follow^: ing requirements in order to be satisfactory for dehumidification purposes: 1. Have a high adsorptive capacity under normal atmospheric conditions. '* 2. Be chemically stable, resisting contamination from impurities. . 3. Be physically rugged to resist breakdown from handling and use. 4. Be capable of reactivation at temperatures generally obtainable. , " 5. Be heat-stable at reactivation temperatures. 6. Have a weight per unit volume such as to avoid excessive bulk. 1 . 7. Be available at reasonable. cost. V >- Activated Alumina . ; Activated alumina is a granular porous material which removes by ad: ; sorption substantially 100 percent of the moisture from gases, vapors, and;.' certain liquids. Regeneration or reactivation may be accomplished by em-. . ploying a heating medium at temperatures ranging from 350 to 600 F.. After many cycles of adsorption and reactivation it is substantially, as effective as originally, and retains its original size and shape. \ Activated alumina is produced by chemically controlled precipitation from a sodium aluminate solution resulting from the extraction of alumina: from bauxite by the Bayer process. By subsequent processes this pro;, cipitate is converted into a highly porous adsorptive material. It is l01?' in iron and silica, each normally less than 1/10 of 1 percent. Commer cially produced material is uniform in analysis and physical form. ; 'Activated alumina is a partially dehydrated aluminum trihydrate con- taining about 7 percent water and small amounts of soda, oxides of iron, silicon, and titanium, as well as very minor amounts of other elemen"' indicated spectrographically. Substantially all of the soda is combmefl with silica and alumina as an insoluble constituent. Activated alumina is inert chemically to most gases and vapors, is non toxic, and will not soften, swell or disintegrate when immersed in High resistance to shock and abrasion is one of its more important phys| cal characteristics. Commercial sizes range from a powder passing throes': 300 mesh screen to particles 1 in. in diameter. The sizes commonly u^r are 8-14 mesh and 1 in. to 8 mesh. The average weight for most forms Dehumidification by Sorbent Materials ;: 863 50 lb per cubic foot. Its high degree of purity warrants classification among commercially pure chemicals. . Silica Gel Silica gel is a prepared form of silicon dioxide (silica) having an ex tremely porous structure which makes it an efficient adsorbent. It is made by mixing predetermined concentrations of an acid, such as sulfuric acid, and a soluble silicate, usually sodium silicate, and allowing the mix ture to set to a jelly-like mass called hydrogel. The product takes its name from its condition as a colloid at this stage of its manufacture. After setting, the hydrogel is broken into small lumps, washed, dried, crushed, and screened to the desired particle sizes and then given a final heat treat ment or activation. The surface area of silica gell has been found to be in excess of 50,000 sq ft per cubic inch of product. Silica gel has high adsorptive capacity per unit weight, and may be reactivated repeatedly at temperatures up to 600 F. Reactivation is generally accomplished by blowing gases through the silica gel at approximately 300 F, or by heating in a well vented oven maintained at this temperature until no more mois ture is given off. Silica gel is a high purity, rugged, non-toxic, heat-stable material, having a specific heat of 0.2, and is most inert. There is no change in the size or shape of the particles as it becomes saturated, and no corrosive or injurious compounds are given off. It is available commer cially in a number of grades, ranging in particle size from a 3 to 8 mesh product to an impalpable powder passing through a 325 mesh screen. The product generally used for dehumidification applications has a particle size of.6 to 12 mesh, and a bulk density of between 40 and 45 lb per cubic foot. Activated Bauxite Activated bauxites are certain natural products which, after controlled heat treatment, have properties which make them suitable for use as solid adsorbents. They are marketed under different trade names by several processors. The activated bauxites consist primarily. of AljOi, Fe2Oj, SiOi, TiOi, and H^O in varying percentages. The surface area, adsorptive capacity, and other properties of the several products differ to some extent, depending upon the source of the original material and its subsequent treatment. The available activated bauxites are durable products having a specific heat of about 0.24, and can be regenerated at temperatures be tween 300 F and 500 F. They are usually supplied in a number of particle sizes, and have a bulk density of between 55 and 65 lb per cubic foot. There are other solid substances having marked adsorbent properties, hut details concerning them are not available. DEHUMIDIFICATION BY SOLID ADSORBENTS th^,nce Sorption is primarily a condensation process, heat, equivalent to is a ^eat evaporation of the vapor, plus the heat of wetting (which "additional amount of heat, depending upon the vapor being adsorbed orat' 6 ackrbenh used) is liberated. The sum of the latent heat of evapa(i.10n ,and the heat of wetting is known as the heat of adsorption. During [lea?rPt'`on, 'I might be said that latent heat is transformed into sensible cont' ca's dissipated into the adsorbent, into the metal of the adsorbent Pi ,lne^> ar>d into the gas mixture, resulting in a rise in temperature, moist saows hhe relationship between temperature, vapor pressure, and Perfofftft con*'ellh i a solid adsorbent. These curves indicate the general tmance of solid adsorbents, although the exact values vary for the 864 CHAPTER 38 1954, Guide' different adsorbents, and may vary even for different types of the same compound. The effects of vapor pressure and temperature upon the mois ture content of an adsorbent may be observed by referring to Fig. 1. When the given type of solid adsorbent is in equilibrium with air having a drybulb temperature of 70 F and 70 percent relative humidity, that is, having a dew-point of 60 F or a water vapor, pressure of 13.2 mm Hg, the water content of the adsorbent is 33 percent. With air having the same dry-bulb temperature and a dew-point of. 37 F, or a vapor pressure of 5.6 mm Hgi the water content is 20 percent. . The increase in .weight for an activated solid adsorbent, after it reaches equilibrium with a gas of any given water vapor content, may be found by subtracting the residual water content (for example 6 percent) from the equilibrium value. In the case of the two examples cited, the actual water'gain would be 27 percent and 14 percent, respectively. The effect of temperature upon the adsorptive capacity may be observed by following the 5.6 mm Hg vapor pressure line. At a ter perature of 70 F, the moisture'cdntent of.the adsorbent is 20 percent, while at 100 F, the equilibrium water content is 11 percent. ,js In practice, the temperature rise in the dehumidified air caused by-the adsorption heat, is approximately 10 deg F for each grain of moisture rw moved per cubic: foot of air at atmospheric pressure. This temperature rise occurs .progressively through the adsorbent bed, and is an important consideration in predetermining the performance of a given design of al* paratus. Data such as these,: together with information covering other characteristics such as specific heat, resistance to air flow, etc., are of value in the basic design of adsorption apparatus. In the solution of air con- Dehumidification by Sorbent Materials : 865 ditioning problems, however, reference must be made to performance data on established apparatus designs. dehumidification equipment using solid adsorbents A typical solid adsorbent dehumidification unit air flow diagram is shown in Fig. 2. The apparatus consists of two adsorbent containers (adsorbers) with necessary interconnecting piping, valves, and auxiliaries consisting of filters, fans, activation air heater, controls, and, in some instances, a cooler for the dehumidified air. Before entering the adsorber, the air to be de humidified is drawn into a filter to remove dust and other impurities. In passing through the adsorbent bed, the moisture content of the air is reduced and the dehumidified air is then introduced into the space or proc ess requiring it. While the first adsorber is dehumidifying the air, the second adsorber is being reactivated by means of outside air drawn through a filter and heater in which its temperature is raised to 300 F. The heat may be supplied by electric heating elements, steam coils, the direct prod ucts of combustion of gas, oil, waste heat, or any other convenient source. In passing through the adsorbent bed, the hot gases supply the necessary heat for releasing adsorbed water from the adsorbent, and then carry it out of the adsorber to the activation gas outlet, where it is exhausted to the outside atmosphere. In some instances a thermostat placed in the acti vation outlet connection shuts off the activation fan and heater when the adsorbent is completely reactivated, as indicated by a rapid rise in the temperature of the outlet activation gas. The length of the adsorption period may be controlled by a timing device which changes the valves or dampers from the adsorbing to the activating position, or by a humidistat located in the dehumidified air connection or in the dehumidified space. The majority of commercial units are time controlled. In applications where a continuous stream of dehumidified air is not required, a single adsorber type unit may be used, while in other cases where a continuous stream of dehumidified air is required, a multiple num ber of adsorbers, or even a continuously rotating system, may be used. If the air to be dehumidified is very warm, and especially where exceed ingly low dew-point dehumidified air is required, it is advantageous to install a pre-cooler to reduce the temperature of the inlet air. In this way the working temperature in the adsorber is lowered, and the overall per formance appreciably increased. Some equipment manufacturers install cooling coils in the adsorbent beds for the same purpose, while others divide fhe adsorbent bed and install coolers between the sections. Dehumidification equipment is employed to the best advantage where the air conditioning problem is primarily one of obtaining low relative humidity control rather than temperature control. This requirement is found in the case of the preservation of inactive naval vessels where the interior of the ship must be kept at a relative humidity below 30 percent to avoid corrosion, mold, mildew, and other moisture damage that occurs nt humidities substantially in excess of this figure. Other advantageous applications for dehumidification systems are found in industrial processes where low relative humidity atmospheres are required during the manufac ture, as well as for preservation of the finished products. Dehumidification With cooling may be used to advantage in work-rooms or other spaces tecupied by humans, where the moisture load is high in comparison to the sensible heat load. In many instances, where independent control of tem perature and humidity is important, dehumidification is used to advantage 10 conjunction with cooling. 866 CHAPTER 38 1954 Guide ABSORBENTS .' / Any absorbent substance may be used as a dehumidifying agent if it has a vapor pressure with respect to water lower than the partial pressure of the water vapor in the mixture from which the moisture is to be removed. Solid Absorbents. The substances used are generally the solid forms of the liquid absorbents. At present they are used principally in small desiccating chambers and in small dryers of the cartridge type, through which air is forced under presure. Calcium chloride is frequently used because of low cost. Liquid Absorbents. These are primarily water solutions pf materials in which the vapor pressure is reduced to a suitable level by controlling the concentration and temperature of the dehumidifying solution. Water solutions of the chlorides ot bro mides of various inorganic elements and certain organic compounds, are the liquid absorbents used in air conditioning. In addition to having suitable water vapor pressure characteristics, an absorbent, to be satisfactory, should also meet the following requirements: 1. Be widely available at low cost. . 2. Be non-corrosive, odorless, non-toxic, and non-inflammable. 3. Be chemically inert against any impurities in the air stream. - 4. Be stable over the range of use. 5. Must not precipitate at the lowest temperature to which the apparatus is exposed. 6. Have low viscosity, and be capable of being economically regenerated or con centrated after having been diluted by the moistlire absorbed. DEHUMIDIFICATION BY LIQUID ABSORBENTS In liquid absorption systems the air-vapor stream is brought into intimate contact with the absorbent solution by passing the air stream through a tower into which the brine is introduced as a finely divided spray, or by passing the air through a tower or contactor which is continuously sprayed with the brine, thereby presenting a large surface of absorbent to the air. to be dehumidified. The difference in the partial pressure of the water in the concentrated brine and the partial pressure of the water vapor in the air,' causes the water vapor to be given up by the air to the brine until equilib rium is approached. The water vapor is condensed during this operation, and its addition to the absorbent solution results in a decrease in the concentration of the solution. As the water vapor condenses, the latent heat of condensation is released in the absorbent solution. An additional, frequently appreciable, quantity of heat known as the heat of solution or heat of mixing, is also released. The heat released as the result of conden sation and mixing, is directly transferred to the brine, to the equipment, and to the air being dehumidified, thereby causing a rise in temperature. A modified system includes meails for removing heat from the absorbent solution, either within the contactor or externally. Thus the temperature of the solution may be higher than, equal to, or lower than that of the air, depending on the chemical employed and the ultimate use of the dehumidi fied air. Fig. 3 shows the relationship between temperature, vapor pressure and moisture content of a typical absorbent of the inorganic type. The* curves indicate the general performance of such absorbents, although the exact values vary for the different compounds. When the given absorbent is in equilibrium with air having a dry-bulb temperature of 70 F and a relative humidity of 70 percent, i.e., having 8 dew-point of 60 F, or a water vapor pressure of 13.2 mm Hg, the wattf Dehumidification by Sorbent Materials 867 content of the solution is 4.8 lb water per pound of anhydrous absorbent. With air having the same dry-bulb temperature and a dew-point of 37 F, or a vapor pressure of 5.6 mm Hg, the water content is 2.1 lb per pound of absorbent. Therefore, when a solution of 2.1 lb water per pound of absor bent is exposed to an atmosphere of 70 F and 70 percent relative humidity, it will absorb an additional 2.7 lb of water in reaching equilibrium. The effect of temperature on the absorptive capacity may be observed by following a constant vapor pressure line in Fig. 3. At a temperature of 70 F and a vapor pressure of 13.2 mm Hg, the moisture content is 4.8 lb Fig. 3. Temperature--Vapor Pressure--Concentration Characteristics for a Typical Inorganic Absorbent (Halogen Salt Group) Fio. 4. Temperature--Vapor Pressure--Concentration Characteristics for a Typical Organic Liquid Absorbent water per pound of absorbent. At 100 F, the moisture content is 1.8 lb water per pound of absorbent. . Fig. 4 shows the relationship between temperature, vapor pressure, and moisture content of a typical liquid absorbent of the organic type. DEHUMIDIFICATION EQUIPMENT USING LIQUID ABSORBENTS One type of system utilizing liquid absorbents includes an external inter changer having essential parts consisting of a liquid contactor, a solution HPecentrator, a solution heater and a cooling coil, all as shown in Fig. 5. ihe contactor and cooling coil are located in the wet air stream. The air P.e conditioned is brought into contact with an aqueous brine solution aving a vapor pressure below that of the entering air, resulting in a trans * moisture from the air to the brine solution. This results in a conver ge of latent heat to sensible heat, which raises the solution temperature "hi conseouently, the air temperature. The temperature change of the 868 CHAPTER 38 1954 Guide'** f air being processed is determined by the cooling water temperature and : the amount of moisture removed in the equipment. Control of leaving__ air temperature may be obtained by precooling the absorbent solution in . a suitable surface cooler, by tap, well, or chilled water. ' The excess water of condensation, which dilutes the brine, is removed in the solution concentrator. This is a low pressure steam heat exchanger which over-concentrates a portion of the weak liquor, and returns it to the.' main brine reservoir for re-cycling. The concentrator operates in the man ner of an evaporative condenser, whereby moisture is evaporated from the. brine by the heating coils into a stream of regeneration air taken from, - and rejected to, the outside atmosphere. Low pressure steam is normally, ' used for heating the brine. When it is desirable or necessary to use gas or electricity, an auxiliary low pressure steam boiler is usually added to the~ equipment. Concentrators operating on a simple boiler principle have not ;, as yet been commercially practical, } It should be noted that the solution concentration phase is the reverse' Coding and- tX Pig. 5. Liquid Absorbent Equipment in Which Solution Cooleb and Contractor are Combined of the absorption process. During concentration, the aqueous vapor pre&O sure of the solution is greater than that of the surrounding air, while during* dehumidification, the reverse is the case. Utilization of this principle perif mits winter humidification by heating (instead of cooling) the solution! pumped to the contactor. Water is thereby evaporated into, instead?!.;' being condensed out of, the conditioned air stream. This requires dilution* of the brine externally to the contactor, rather than concentration. '' naffi'v CALCULATION OF MOISTURE LOAD , Calculation of the dehumidification required to maintain lower tHan?; normal moisture content in a given room begins with determination of the ; rate of moisture gain in the room from all sources. It is common praetkfj'f when maintaining a low humidity ratio, to recirculate a large percentage^' the air in the room through the dehumidifier, and to add only enough out- ? side air to meet the needs of the problem. The humidity ratio ofjtyh mixture of outside and recirculated air and the dehumidifier perfonnangg data can be used to calculate the humidity ratio of the air leaving the;#" humidifier. The difference between the humidity ratio of the air in room and that of the dehumidified air entering the room represents^ Dehumidification by Sorbent Materials 869 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 a general method of determining the dehumidifying requirements. Sensible heat determination considerations are discussed in other chapters, and are pur posely omitted here. ' : Example 1: A solid absorbent dehumidifier having performance characteristics as shown in Fig. 6 is to be used to maintain inside conditions of 73 F and 20 percent rela tive humidity, i.e., 24.1 grains per pound of dry. air, 30 F dew-point, in a room 20 ft x 30 ft x 10 ft high, having a total wall, ceiling, and floor surface area of 2200 sq ft. Outside design conditions are 72 F dew-point (11814 grains per pound). Internal sources of moisture are: 4 occupants; an open natural gas burner using 15 cu ft of natural gas per hour; an open top water tank, having an area of 2 sq ft ex posed surface, in which water is maintained at 87 F, with air movement over the water surface being 100 fpm. Determine the quantity and condition of the dehumidified air to be supplied to the room. ; Solution: The internal moisture gain consists of items 1 to 5. 1. From occupants: ' 4 X 1800/60 = 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 = 1 cu ft natural gas produces approximately 650 grains of moisture. . 3. From exposed water surface: : 2 X 20 = Evaporation from water surface is assumed to be 20 grains per (minute) (square foot) at 87 F water with air movement of 100 fpm. 4. From infiltration: - 60 6x01030 56 * U1' 8.4 --. 24.1) = One air change, 6000 cu ft, assumed per hour (see Chapter Grains per Minute 120 162 40 696 5. Moisture transmitted through room surface: 9200 - . -- X 3 X (0.783 - 0.176) = Permeability assumed to be 3 grains per (square foot) (hour) (inch Hg vapor pressure difference on two sides of wall). 67 Total moisture gain from internal sources Let ? be the air delivered to the room, pounds per minute. 1085 {h*,3 p-rojbsl>ewmuutvhat 8U5CpltVeCrclte/UntVoU fHtUhGeA Wairilli)s re__c__irc__ulated a. n.d 15 pLe---er--c-t-e--i-nt---t-b---ie-s-JaVosIustusmideedafoirr, 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, which ever is greater. The amount is estimated from experience or obtained by test.. dfZhe- ^idity ratio humidifier is then: of the mixture of recirculated and outside air entering the 0-85^(24.1) + 0.15g(118.4) 0.85? + 0.15? 38.3 grains per pound entering dehumidifier. Pound ^humidifier whose performance is shown in Fig. 6, for 38.3 grains per m entering air, the leaving humidity ratio will be 6.5 grains per pound. 8uPply ai^6 dehumidification in the room is 24.1 -- 6.5 or 17.6 grains per pound of 870 CHAPTER 38 1954 Guidef|j' > >/ Fio 6 Performance Data fob Typical Commercial Solid Adsorbent '' Dehumidifier Then o = 170?8-5.--g--rai:n--s p-e--r--m---i-n-u3t-e= 61.6 lb air per min. ute. min. im. um th.,at,must.W^ 17.6 grams per pound supplied to the room to maintain 30 F dew-point. Note that this figure represents the minimum requirement for the arbitrary condiy tions set forth and that in practice, safety margins should be added to the outside air, percentage figure and to the calculated internal moisture gain. VAPOR TRANSFER TO DEHUMIDIFIED SPACE | The walls enclosing a dehumidified space are subjected to a vapor pres sure differential. The pressure of the vapor outside the walls tends *! . force moisture through the walls into the dehumidified zone of relatively' low vapor pressure. As this process can be an unnecessary load on IK dehumidifying equipment, provisions should be made for keeping the vapor transfer to a minimum. Also, if the space is cooled below the arnbien* dew-point, there is a possibility that condensation may occur within tig. walls, unless vapor transfer is controlled. For these reasons a vapor bar rier should be located within the wall construction as near to the high vapor pressure side as feasible. To be effective, a barrier must be continuous and should be so located within the structure that it will be protected frp rupture. (See Chapter 10, Water Vapor and Condensation In Building Construction). j CHAPTER 39 AUTOMATIC CONTROL Basic Types of Control, Types of Controllers, Actuating Devices, Indicating and Recording Equipment, Actuated Controls, Automatic Control Application, Residential Control Systems, Steam Heating Systems, Hot Water Heating. Systems, Unit Heaters, Air Supply Ventilating Units, Unit Coolers, Refrigeration and Dehumidification Equipment, Central Fan Systems, Panel Heating Control, Individual Room Control, Zone Control, Design Coordination . THE function of automatic control, as applied to heating, cooling, ven tilating and air conditioning, is to maintain temperature, humidity, and pressure, within pre-determined ranges. It coordinates the operation of the various controlled devices in proper sequence to produce the desired result.1'2 BASIC TYPES OF CONTROL Available automatic control equipment may be divided into, four main groups depending on the primary source of energy: 1. A self-actuated regulator is one in which all the energy necessary to actuate a valve or damper operator is supplied by the responsive element or bulb. Tempera ture changes at the bulb result in pressure or volume variations of the enclosed media which are transmitted directly to the operating device of the valve or damper. In struments of this type are available either with a rigid bulb or with flexible tubing from the bulb to the operating bellows or diaphragm. The flexible tubing may be furnished in varying lengths, and is generally protected by a flexible metal armor. 2. Electrically operated equipment utilizes electric current as a primary source of energy, its flow being regulated as required to operate motors, relays, or other con trolled items. Electrical controls may be divided into two classes: (1) those wherein the primary measuring device makes or breaks contacts to regulate the flow of the electric cur rent, and (2) those wherein the primary measuring device is a resistance wire com ponent of an electrical circuit. . 3. In pneumatically operated equipment the primary source of energy is compressed wr usually at a pressure of 15 to 25 psig. The flow of this air is proportioned as re quired to operate valves, dampers, relays, or other controlled devices. 4. In hydraulically operated equipment the primary source of energy is a suitable hquid at a pressure of 15 to 25 psig or higher, which may be regulated after the same manner as compressed air. TYPES OF CONTROLLERS The basic types of controllers and their operations are: bv*k Tw>-pofton.r on-off controllers are the simplest type and are clearly described on) e name\ With controllers of this type the valve or aamper operator can assume *y two positions, either open or closed. , Proportional or gradual acting controllers function to reposition the controlled chftICe' ^ small increments to regulate the flow as the controller senses a slight uange from the desired conditions. The valve or damper or other device may take y position, including open and closed. vaf ^utoTn<itic reset (or proportional plus reset) controllers function to reposition a lerVe 0r damper as in a proportional controller. In addition, a device in the controlfro autk0matically resets the instrument whenever the controlled variable deviates sad1 desired value due to load changes. The rate of reset is manually adjustable u must be set to meet the load requirements of the individual system. Controllers may also be designated by types as: a non-indicating con- 871 872 CHAPTER 39 1954 Guide trotter, when it does not indicate the controlled condition and performs the control function only; an indicating controller, when fitted with a pointer, thermometer, or gage which indicates the controlled condition; a recording controller, when it is combined with a clock mechanism and chart which records the controlled condition. ACTUATING DEVICES The starting point of any control system is the thermostat, hygrostat, pressure regulator, or other mechanism which is sensitive to a change in the controlled variable and which responds in the desired manner. Thermostats are usually of the room, duct, or immersion types. Various types of thermostats found in common use are defined in the following paragraphs. 1. A thermostat is an instrument which is responsive to changes in temperature', and initiates a force that repositions valves, dampers, etc., to maintain selected temperatures. 2. A room thermostat is usually mounted on the wall of the space to be controlled with the measuring element arranged so that it is affected by the room temperature. 3. A duct thermostat is provided with fittings suitable for installation in an air or gas duct. The insertion type is equipped with a rigid bulb and is arranged so that the temperature responsive element or bulb extends through the wall of the duct. The remote bulb type is arranged so that the bulb and instrument head are connected by means of a flexible tube of the desired length. The bulb is inserted in the duct, and the head is located where it is accessible for adjustment and inspection. 4. An immersion thermostat is provided with fittings suitable for installation in a pipe line or tank where a fluid tight connection is required. Both insertion and remote bulb types are available. A union connection and separable socket, when used, permit removal of the bulb without draining the line or tank. The sockets may be of copper, stainless steel, or other materials. . 5. A day-night or two-temperature thermostat controls a heating or cooling source to maintain either of two selected temperatures. They may be indexed (set at de sired control temperature) or reset individually or in groups from a remote point by means of a manual or time switch. 6. A summer-winter or heating-cooling thermostat is similar to the day-night type, except that both the temperature setting and action are changed by the indexing means. Such a thermostat may close a valve or damper on a rising temperature in winter and may open the same valve or damper on a rising temperature in summer. The function of such thermostats may be reversed by a remotely-located switch or by a separate thermostat. . 7. A submaster thermostat has its temperature setting raised or lowered a pre determined amount for a given change in some other variable. For example, the water temperature on a heating system may be raised as the outdoor temperature drops. A master instrument is used to reset a submaster thermostat and may be s switch, pressure controller, thermostat, or similar device. In the foregoing example the master thermostat would be located where it would respond to outdoor tempera ture, and the submaster thermostat would be located in a pipe of the heating system. A hygrostat is a controller which is sensitive to changes in relative humid ity, and is available in room and duct types. Where the controlled condi tion is below 20 percent or above 80 percent, or where the temperature is above 100 F, selection of a suitable type and kind of hygroscopic element is essential. - A pressure regulator is a device which is sensitive to changes in pressure- It may be of the type which controls a single pressure or of the differentia* type which maintains a predetermined difference between two pressures- For pressures in duets, static pressure regulators are available in the wr ferential type. They may respond to pressure changes as small as 0.0m in. of water. Automatic Control 873 INDICATING AND RECORDING EQUIPMENT In addition to the automatic control of temperature and humidity con ditions, visual indication and permanent chart records of the variables in volved, are desirable. They provide an accurate check on the performance of the system, both from the standpoint of conditions maintained, and cost of operation. Instruments are available to provide accurate records of these variables such as pressure, temperature, humidity, flow, and CO?, which go to make up a complete heating or air conditioning system. In some cases the control equipment is provided with indicating or recording mechanisms, by means of which the performance of the controls may be observed or recorded, and in other cases,, separate instruments are used for the purpose.1 . .. -. ACTUATED CONTROLS Thermostats, hygrostats, pressure regulators and other actuating devices obtain' control of heating and cooling mediums, fuels, liquids, etc., by actuating various control devices such as control valves, dampers, damper motors, relays, or controllers defined in the following paragraphs: A control valve is designed to control the flow of fluids, and may be con sidered as a variable orifice which is repositioned by an electric motor, a pneumatic bellows, or a diaphragm (commonly called a.n operator) as directed by a thermostat or other controlling device.' 1. A normally open or direct acting valve will assume sin open position when all operating force is removed. ' - - -- 2. A normally closed or reverse acting valve will assume a clospdposition when all operating force is removed. ' '' 3. Single seated valves are designed for tight shut-off using appropriate disc mate rials for various pressure ranges and fluids. : 4. Pilot piston valves serve a similar function on high.pressure installations. ` 5. Double sealed or balanced valves are designed bo that the fluid pressure acting against the valve discs is.balanced and does not oppose the force of the operator. They are not affected by-varying inlet pressures or pressure differentials, and are thus widely used where these conditions exist, or where the fluid pressures are too high for a single seated valve to close. They cannot be used where tight shut-off is required. ' 6. A three-way valve has three pipe connections. The inner structure has two ports and either a double faced disc or two separate discs, operating so that As one port opens the other closes, and vice versa. Depending upon manner of installation, it may be used as: a. A three-way mixing valve to mix, as required, two fluids entering the two inlet connections and leaving through the common outlet connection. b. A three-way diverting or by-pass valve to divert the flow from the inlet con nection to either of the two outlet connections. Valve discs, poppets, and seats, are available in various shapes to meet any desired flow characteristics with various fluids as required by service conditions. For satisfactory operation control valves must be accurately sized for the required capacity, pressure and service conditions. Most manufac turer's catalogs include capacity and pressure drop data as well as recom mendations for maximum pressures and materials to be used for various services. . - A damper is designed to control the flow of air or gases, and functions like a. valve in this respect. Single blade dampers are generally restricted in Slze because of.the difficulty of securing proper operation with high velocity 874 CHAPTER 39 4954 Guide air. Multi-blade or louver dampers can be furnished so that adjacent' .blades move in the. same direction or in opposite directions. - The opposed blade type gives better directional air flow characteristics than the parallel blade type. ..=.-. ... . . - ' : .- -. . For long life and trouble free operation,- dampers should be constructed with heavy metal frames, blades adequately braced, and ample bearing surfaces of norircorrosive materials. ' When -tight closing is desired, felt may. be:glued and rivetediondhe edgra-and; ends of.`.-the-blades.-" .Special .material for blades and frames are also available. ' : - A' damper operator is repositioned by a controlling instrument, and is connected to the damper blades as required to give the desired movement It can be mounted on the damper frames or mounted outside the duct' and connected to an extended shaft on pne or more damper blades. Suitable brackets are available for floor, wall, or duct mounting of the damper operator. - .. .. - A relay is a device which uses an auxiliary source of energy to amplify or convert the force of a controller into available energy at a valve or damper operator. Various types of relays are designated as follows: .-1: An electro-pneumatic relay, when electrically energized, Btarts .or. stops'the flow of air as required. . , 2.. A pneumatic-electric relay, when affected by different air pressures, starts or stops the flow of electrical energy as required. 3. A switching relay or pilot valve may be used to switch the operation of a con trolled device from one controller to another, or to reverse the action of a controlled device in response to an impulse from a controller. , . 4. An averaging relay is affected by the forces from two or more controllers, and the resulting flow of energy is in accordance with the average of these forces. . .5. A positioning relay has a direct: connection to the operator of a valve and is affected by both valve or damper position and controller demand. It is repositioned by. a thermostat or other controlling device, and is arranged to give a definite posi tion for a given force from the thermostat regardless.of friction or pressure variations of the controlled fluid. . .6. There.are numerous other relays such as differential,.retard, advance, and linwj relays-for highest pressure or lowest pressure which are used to provide the. desired sequence of the control devices. , 7. An electronic amplifier is used only in electronic control circuits to amplify the micro-currents of electronic controllers to usable voltages required by standard elec tric .actuating devices. It may be either two-position or proportioning. - A sequence controller is used to operate two or more devices in a pre arranged sequence. It is generally, used in connection with refrigeration compressors, and may be arranged to prevent simultaneous- starting in the event of temporary electrical shutdown or in failure, of the control medium. : . ..." Manual switches are available in the two-position or proportional typesTwo-position switches change the flow of energy from one circuit to one or more other circuits; or from one pair of lines to another pair of lines. Pro portioning switches vary the flow of energy as determined by the manual setting of the switch. - - Positive switches are stop-waste, three-way or four-way cocks, and .are used to open or close a controller, or make a night and day change-over. Gradual switches may vary the flow of energy to an actuator. AUTOMATIC CONTROL APPLICATION Some of the considerations affecting the selection of automatic control? for applications are given in the following paragraphs which describe con Automatic Control '875 trols and operation for various types of systems and equipment; ; The subdivisions describe combinations of controls and devices that are particularly applicable to that individual type of equipment. Certain portions of any specific automatic control system may also be applicable to other systems, or be used in combination with-these control systems. RESIDENTIAL CONTROL SYSTEMS The control equipment function in a residence may vary from, the regulation of a coal-fired heating plant to the completely automatic control of an all-year air conditioning 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 occupants, as well as economy of operation. . '.. . ,' .i ' .' . Heating Unit Controls . .. . Typical controls for the appliances used, to supply heat in residences are as follows: ' 1. Hand Fired Coal Burners. The control of a hand fired coal burner for a boiler or furnace normally consists of a room thermostat operating a two-position electric control motor, which in turn opens the draft damper and closes the (meek damper on a demand for heat. The motor then closes the draft damper and opens the- check damper when the thermostat is'satisfied. -';A limit control on the boiler or furnace should be connected to the motor so that: it may checkithe fire whenever'a.prede termined temperature or pressure has been exceeded. A manually operated base ment switch usually is included on the motor so that the draft may be opened and the check closed when the boiler'or fuinace is being filled with coal. : . 2. Coal Fired Stokers. Domestic stokers usually are controlled by a'rbdm thermo stat, a limit control, and,a stoker relay. When the thermostat calls for heat, the relay causes the stoker motor to increase the flow of fuel and air to the burner. When the thermostat is satisfied, the relay provides for a reduced flow of fuel and air to tin; burner to maintain the-fire at its minimum rate. The limit control prevents the con tinuance of the maximum fuel rate if the temperature or pressure in the boiler or furnace exceeds a predetermined value, and also stops the feeding of fuel if the fire goes out. . .. 3. Automatic Oil Burners. Automatic oil burner controls normally consist of a mom thermostat, a limit control, a combustion safety control, and. a. control relay. On a call for heat by the thermostat, the relay starts the oil burner motor which supplies oil and air to the burner. An ignition device consisting of an electric spark of a gas flame ignites the oil automatically. If for any reason the oil and gas mix ture does not ignite, a time delay mechanism in the relay is operated by the com bustion safety control after a predetermined length of time, to cause the oil and air supply to be shut off. If the oil and air mixture ignites property, the burner con- th"*eS run un^ the thermostat is satisfied, or until the limit control affected by be temperature or pressure in the boiler or furnace stops the burner. . cl H Automatic Gas Burners. The controls for an automatic gas burner usually inude a room thermostat, a limit control, a safety pilot, gas pressure regulator and a Ebs valve (solenoid, motorized or diaphragm type). Upon a demand for heat at the ermostat, the gas valve is opened, admitting gas to the burner! The safety pilot gnites the gas which continues to burn until the thermostat is satisfied, or until the it control shuts off the gas valve. The limit control may also reduce (throttle) ?a3 flame as required to maintain a desired temperature or pressure of the heating thp 1Uni ^ the pilot flame is extinguished for any reason, either before or after ,, bbuin gas valve is turned on, the safety pilot closes the gas valve, thus eliminating danger of delivering gas to the burner without ignition. elect Electric Heating. Electric heating has become popular in those areas where locate Power *3 plentiful and inexpensive. The electric heating elements may be roo 11,1 ln eah individual room and turned on and off by thermostats in each TM.,f fbe heat may be supplied by a central heating system. In the case of a gize f "ea^*nB system, the control is usually of the proportioning type which ener gy ,8 h ve ten beating elements in sequence, according to the demand for t, by means of a sequence controller consisting of a series of switches operated by 876 CHAPTER 39 1954 Guide a proportioning motor. A limit switch recycles the sequence controller if the furnace or boiler exceeds a predetermined temperature. Limit Controls ' A high limit control for steam consists of a pressure-sensitive element, having bellows responsive to the boiler pressure. It opens an electric contact when the steam pressure exceeds a predetermined point, thereby preventing the burner from delivering additional heat to the boiler. A low water cut-off should also be used to stop the burner, if the water in the boiler drops to a dangerous level. -. : A high limit control for a hot water boiler consists of an immersion thermostat (usually equipped with a bi-metal helix) inserted in a well in the boiler. This control stops the burner when a predetermined water temperature has been reached in the boiler. ,. In a warm air system the high limit control is a thermostat including a bi-metal helix inserted in the bonnet of the furnace. It will shut off the fuel supply when a predetermined furnace temperature is exceeded. Room Thermostats , Room thermostats are of three types, depending on the temperature sensitive element which they employ. These are: (1) the bi-metallic type which distorts with temperature changes; (2) the vapor-filled bellows type which expands or contracts with temperature changes; and (3) the elec tronic type which employs resistance wires, and microcurrents which vary with temperature or humidity changes. The first two types employ either electric currents or compressed air to amplify their effect. In the electronic type the micro-currents are amplified by means of electronic amplifier- relays. The amplified effect in each instance is used to actuate the opera tors for valves, dampers, stokers, oil burners, gas burners, etc. Rooin thermostats may be of the plain or single temperature type, or of the daynight type providing for automatic night decrease and morning increase of the control setting. The automatic setback type usually includes a clock mechanism which accomplishes this result. Opinions vary regarding the amount of fuel that can be saved by automatic setback. Tests made both in the Warm-Air Heating Research Residence and the I = B =;! R Research Home at the University of Illinois indicate that, on thermo statically controlled systems, a possible fuel saving of from 7 to 10 percent may be obtained by reducing the house temperature 6 to 10 deg from about 10:00 p.m. to 5:30 a.m.s . ,,!> In locating a room thermostat the following rules should be observed: 1. It should always be located towards the center of a relatively open room on the coolest rather than the warmest side of the building. ,:tt 2. It should never be mounted on an outside wall or other cold surface, or wheff it is exposed to cold drafts from an outside door. . ;; 3. It should never be mounted where it will be affected by direct rays ot the sub; by heat from a nearby warm surface such as chimneys, pipes or ducts in a wall, Rr radiators; or by direct currents from a warm air register. 4. It should never be located where normal circulation of air is impeded by furni ture or an opened door. . . -'is 5. It should be located where it is protected from mechanical injury. " In a typical home, a satisfactory location for the thermostat can usually be found on an inside wall of the living room or dining room. In laflS$ buildings the thermostat or thermostats should be placed in occupied Automatic Control 877 areas on inside walls or columns. They should never be placed in cor ridors, lobbies, foyers, etc. unless they are used, for the control of these, areas only. : System Control ' There are several types of system control in common use for residential applications. They are usually of the two-positioqr(on-off) type, or of the proportioning type. :, . 1. Two-Position {On-Off) Control. The most simple type of domestic control is one in which the room thermostat starts the burner or other soiirce of. heat when the temperature of the air at the thermostat falls below the thermostat setting, and which stops the source of heat when the:air temperature rises above the setting. If forced warm air or.forced hot water is used, the fan or circulator may be turned' on and off at approximately the same time as the source of heat.1 1 2.Proportioning Control. When a proportioning type of control is used, the flame of the burner may be varied, or the burner may be cycled (started and stopped) frequently to provide for time modulation so that the heat input to the home is proportioned continuously to the heat loss from the home. The fan of a. forced warm air system or the circulator of a forced hot water1 system may be rim almost continuously, thereby providing for the constant flow of heat into the home. Such operation minimizes the cold drafts on the floor as caused by cold air dropping from cool walls and windows during the off period of an on-off system. Zone Control In residential heating, it is often desirable to divide the house into two or more zones for greater accuracy of control and comfort. Each zone may then be maintained individually at the desired temperature level. The division by zones should be based upon exposure and occupancy; the most common division is usually found to be: . . 1. Living section such as living room, dining room, den. 2. Sleeping section. - 3. Service section such as kitchen, pantry, servant's quarters. 4. Recreational areas. Further discussion of zone control will be found in the general section on Zone Control given later in this chapter; Air-Conditioning Systems . Year 'round residential air-conditioning systems which provide for heat- Mg in winter and cooling in summer should be given the -same considera tion in selecting the control system as required for commercial air-con ditioning systems, since the basic principles are the same anti the final results must provide for the comfort of. the occupants. A reduction in hivestment in first cost for automatic controls may result in wasteful operation of the system and discomfort for the occupants. . STEAM HEATING SYSTEMS There are several means of obtaining centralized control of heat output ` radiators in heating systems whether the steam comes from a local boiler or from underground mains. 1. Controlling the rate of steam flow into the radiators. This is accomplished by ??UlPPmg the radiator inlets with orifices, and controlling the flow of steam through ""Zm into the radiator as a result of the difference in pressure between the supply and return connections. _ Controlling the temperature of steam in the radiators by varying its pressure, mi i Lnvoh'e6 the use of high vacuums to obtain low steam temperatures. This 1st be supplemented by some other type of. control for low heat output. 878 CHAPTER 39 1954 Guide . ,_3. Controlling the length of-time steam flows into the radiators by admitting steam intermittently, and varying the.length of the on and nff periods. Two types of controls are used. (1) A clock control providing on and off settings of various lengths, which can be changed in accordance with outside temperatures. In most cases these changes are made automatically by means of a thermostatic bulb, placed out doors. (2) A control, having an outdoor bulb and a bulb attached to the radiator, which varies the length and frequency of the on intervals in such a way that the radi ator temperature is varied according to the outside temperature. In some cases heat supply is controlled by combinations of the three methods. Before installing any type of modem temperature control equipment, it is necessary to see;that the heating system is iput in good operating condi tion.- In general,' the heating system in a building is not given the atten tion that pther inechanical equipment is given, because it will continue to function, after a, fashion, eventhough changes in piping, location of radiation, and settlement have taken, place., -Because of this depreciation of the system,, operation ,becomes, more ,costly, and parts of the building may have i to be greatly overheated in-order to prevent underheating in other parts; Vents, traps; vacuum pumps, and valves should be given a careful inspection arid replaced or repaired, if required; The piping should be of adequate size and graded properly. : The return piping should be inspected, and any pockets or lifts removed arid properly vented. These inspections and repairs are not costly; arid may prevent a much greater outlay in future years. . , , HOT WATER HEATING SYSTEMS iSome-of the'more generally-accepted methods of controlling hot water heating systems are :: 1. Controlling the flow of water supplied to the system while maintaining a con stant water temperature in the boiler or converter storage tank by: a. Starting and stopping the circulating pump by means of a, room thermostat. b. Maintaining a constant pump circulation and stopping the water circulation to a zone or several zones by the use of positive acting valves under the control of room thermosats. 2, Varying the temperature of the water supplied to the system in accordance with' the variations of the outside weather conditions, while maintaining constant water circulation to the system, and ; ' ' .' a. Regulating the volume of water to each room or zone by gradual acting valves under the control of room thermostats. .: - -A b. Stopping the flow of water to each room or zone by positive acting valves under ....... the control of room thermostats. c. Arranging the piping and regulating valves, such as three-way valves, under the control of room thermostats to further modify the water temperature: in , accordance with the heating requirements of the room or zone. '> / Whatever the mechanical features of the regulator may be, its func-/ tiori.is to dictate the flow impulse, or rate of flow, in such a way as to, maintain the desired indoor teiriperature in a zone, regardless of the fluctu ations in the outdoor temperature. -. : UNIT HEATERS _ The standard method is to stop and start the fan by means of a two-,, position room thermostat. A limit control may be provided to prevent operation of the fan when no heat is being supplied by the connecting^ services. Sometimes a separate manual switch may be connected so as, to permit operation of the fan for ventilating purposes at times when no: heating is desired. . A proportioning room thermostat may control a modulating valve in^, the connecting service pipes, if continuous fan operation is maintained.'"``v. Automatic Control 879 ' AIR SUPPLY VENTILATING UNITS ; There are several different acceptable control cycles. The choice may be governed by compulsory ventilation codes. Usually there is a room thermostat that governs a heat supply valve, an air supply damper and a thermostat in the entering air stream for each unit. The room thermostat controls heat supply to such auxiliary , heat transmitters as may be in the room. In Control cycle No. 1 a fixed minimum volume of air isdrawn from out of doors at times when the room temperature is at the design level. When the room is too cool, the damper is closed to outdoor air and is open for.recirculated air from the room, and the heat supply valve is open. As the room temperature approaches the desired de gree, the damper moves,to admit more air from out of doors and reduces the volume recirculated. A further increase'In room temperature causes throttling of the heat supply valve. Ultimately if the heat supply valve closes completely, the outside air damper opens wide and recirculation of any part of the air ceases. During the com plete cycle, the thermostat in the air stream prevents entry of air so cool as to pro mote chilling. .1 1 Control cycle No. 2 sometimes is employed and is the same a3 cycle No. 1 except that the outside intake damper opens a minimum amount or is closed without an in termediate position; the recirculating damper being adjusted accordingly, The minimum quantity may be adjusted as any desired percentage of the capacity of the device. --- . . . . , .. Control cycle No. S has a stream-line thermostat in the mixed air stream to adjust the dampers so that if the room air is too cool, the outside air damper is closed and the valve on the heat supply pipe is open. As the room air temperature approaches that desired, the room thermostat takes control of the valve and the stream-line thermostat opens the damper in the outside air.intake while moving the recirculating damper to reduce the amount of recirculation. , ,. Auxiliary heating devices in the rooms that have unit ventilating' machines should be controlled in sequence with the control cycle employed for these ' machines. .: Day-night thermostats often are used with unit ventilating machines to permit reduced night temperature, with corresponding economy. For the night setting, the fan-motors may be idle, while the heaters are cir culating warm air by gravity. ' It is also possible to provide intermittent operation of the fan motors while operating under control of the night or reduced-teinperature thermo stat. - 1 . ' In many large schools it is possible to arrange for separate control cir cuits rather than for separate steam mains so that offices and toilet rooms may be controlled at a temperature considerably warmer than that of other rooms. , UNIT COOLERS Although most unit coolers, can be adapted to any control cycle, con tinuous 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 ob tained from the temperature of the recirculated air and from suction pres sure. 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. REFRIGERATION AND DEHUMIDIFICATION EQUIPMENT . Typical control equipment and its functions are described in the follow ers paragraphs. . ,/ Well Water. Where well water is used directly in air washers or cooling coils, 880 CHAPTER 39 1954 Guide control of temperature or humidity usually is obtained by thermostat- or humidistatoperated valves (two-position or proportioning). The two-position valve will pro vide better dehumidification since a lower coil temperature will be maintained, but the temperature of the discharge air will fluctuate. With proportioning thermostats, better control of discharge air temperatures will be maintained. In both cases the sensible-latent heat ratio is basically a matter of coil design rather than a matter of automatic control. Proportioning three-way valves may be used as mixing or diverting valves for better pump performance, and may also be applied to an air washer used with a recirculating pump to control water temperature rather than vol ume. % Ice Bunkers. Where water is sprayed over the ice in bunkers and circulated to air washers or cooling coils, control is obtained by a thermostat in the water line from the bunker: The thermostat proportions a three-way valve to by-pass enough return water around the ice bunker to maintain a constant discharge temperature. Compressors. Compressors may supply refrigerant to direct expansion cooling coils in air conditioning units, or to direct expansion coils in water-chilling units. In either case, the compressor motor may be started and stopped directly, by a room or duct thermostat, or a pressure controller may be used to regulate the suction pressure of the compressor. In the latter case, a room or duct tnermostat may be used to control a solenoid valve in the refrigerant supply line to the cooling coil. A high and low pressure cut-out is standard safety equipment on most compressor installations. Reduced capacity of the refrigerating unit may be obtained by means of temperature or pressure controlled unloading devices which vary the capacity of the compressor in some proportion to variations of cooling load. Program or step controllers, actuated by temperature or pressure, are commonly used in multiple compressor installations. It is desirable in such installations to return the program or step controller to the of position when the system is shut down to prevent the full electrical load of multiple compressors from being thrown across the line at the same time. Thermostatic control of water supply to water-cooled condensers may be achieved by means of self-contained controllers or valve and thermostat application. Steam Jet Evacuators are controlled by a thermostat (in the chilled water) which adjusts a two-position steam supply valve. Multiple jets can be controlled by valves that open or close in sequence. This may be accomplished by using spring of different resistance to the operating force released by the thermostat. Automatic temperature control definitely is advisable. Centrifugal Units. The control of. centrifugal refrigeration units or other types of vacuum systems is customarily achieved by means of a thermostat in the chilled water to control the operating cycle of the equipment at full or reduced capacity. This is usually accomplished by the automatic regulation of vortex dampers at the inlet of the rotor. Adsorption Units. Control of adsorption refrigeration may be obtained by a damper which, in response to humidity, varies the rate of air flow through or around the activated bed of adsorption material. Standard controls for cooling are used to reduce the dehumidified air to a.desired dry-bulb temperature. Absorption Units. Since at constant density, the absorption solution will extract water from the treated air in an amount proportional to the solution temperature, the moisture content of the air leaving an absorption unit is regulated by solution temperature. Solution density is held constant by a combination of float control and steam valve controlling the solution regenerator. Two basic methods of control are standard: . 1. Constant solution temperature where the solution temperature is set so that,at the full load for which the unit is designed, the discharge air will have the desired moisture content. Proportioning control of the water and two-position control of the steam are recommended to maintain constant temperature. 2. Control by varying the solution temperature so that the moisture content of the discharge air remains constant regardless of load variation. Basically, this control is similar to the constant solution temperature control, with the addi tion of a hygrostat or wet-bulb controller controlling thewater valve from spaco conditions. In order to gain a constant dry-bulb outlet temperature a heating coil is placed in the air stream and is served by a valve that responds to a pro portioning thermostat in the discharge air stream. 1 CENTRAL FAN SYSTEMS Automatic temperature control for central fan heating, cooling, ventilst- . ing, and air conditioning systems involves the proper application of various Automatic Control 881 types of controlling instruments and associated regulators such as valves, with operators, dampers with operators, relays and other auxiliary equip ment which are described in earlier sections of this chapter. In central fan systems the conditions required dictate the type of built-up control system to be used. It is impossible to state in detail the control apparatus which will be required in even the most representative applications. In general, in so far as automatic temperature, and humidity control equipment is concerned, central fan systems may be divided into certain broad classifications, as follows: (1) heating, (2) humidifying, (3) ventilat ing and atmospheric cooling, (4) cooling and dehumidifying, (5) control of zone temperatures, (6) year 'round air conditioning with automatic change over, (7) constant temperature and humidity. The apparatus which enters into the automatic maintenance of tempera tures and humidities for central fan systems which are designed to produce each of the effects listed in items 1 to 7, is indicated in the following para graphs: ; 1. In heating control, there are three principal items to be considered: (1) control of temperature in the space; (2) prevention of objectionable drafts: (3) prevention of freezing within the space or in any part of the equipment. Usually in central fan systems, suitable .thermostats operate valves in the steam or hot water supply to heating coils, or adjust'face dampers across such coils and by-pass dampers around them. If the heating coils are sub-divided into two or more groups, such as pre heaters and reheaters, a duct thermostat (following the preheaters, and located in the entrance to the chamber between the groups of coils) controls the preheaters; but it is essential that the preheater coils be of the steam distributing type. Similarly, a duct thermostat in the fan discharge, where any effect of stratification has been dissipated, operates the valves and dampers associated with the reheaters. In Some cases, where there are more than one bank of preheaters, the practice is to place a freeze protection thermostat in the outdoor air intake to control the valve on the first bank of heaters, which is designed so that the heat-rise, through it will not cause overheating. A room thermostat in the heated space may. serve as the controlling instrument, with a thermostat in the fan discharge serving to prevent the delivery of air at a temperature which might cause drafts. If desired, similar action may be obtained from a thermostat in the return air connection. When there is only one heating coil, a limit thermostat in the fan discharge accomplishes the control, in conjunction with a thermostat in the heated space or in the return air. 2. Humidity control may be obtained by means of a hygrostat, usually located in the conditioned space or in the return air. Such controlling instruments may operate steam supply valves to humidifiers, mixing valves to control the temperature of the water to sprays, or a system of dampers to regulate the quantity of air passed through the humidifying chamber or by-passed around it. The control of humidity, ac cording to dew-point temperature, is sometimes accomplished by means of a thermo stat in the outlet of the humidifying chamber. However, the setting of the dew point thermostat may have to be reset to compensate for varied space conditions. 3. The control of ventilating and cooling by the use of outdoor air consists of an arrangement of dampers, usually determining the relative quantities of outdoor air and return air which are to be delivered to the conditioned space. The damper positions are regulated by proper types of thermostats, located in the minimum outdoor air intake, the fan discharge, the conditioned space or the return air. In struments are available which, with an adequate arrangement of dampers, will cause a maximum quantity of outdoor air to be handled until it becomes more eco nomical to utilize return air. . I. Cooling and dehumidifying may be controlled by means of thermostats, and nygrostats or dew-point thermostats, which regulate dampers and mixing valves to maintain air of the proper temperature and humidity in the discharge from the central fan plant. Such controlling instruments normally are located in the fan uischarge or in the return air, or both, and they may be associated with thermostats or hygrostats in the conditioned spaces. ' 5. Where a separate duct serves each zone of an area with which a central fan system s associated, a room thermostat in each zone may operate mixing dampers in the met to each zone duct, determining the quantity of warm air which is required t0 fhat portion of a plenum chamber into which heated air is delivered, and the quantity of cool air which should be taken from the other portion of the double 882 CHAPTER 39 1954 Guide plenum chamber. In many instances, separate, zone .heating and zone cooling coils are employed, instead of mixing dampers. . 6. The control hook-up for a typical year Wound air conditioning system, including automatic change-over from heating to cooling, is indicated in Fig. 1 and described as follows: Whenever the fan is started, solenoid air valve or relay E-l, actuated by the fan motor Btarter, opens minimum outdoor air damper D-l, places hygrostat H in service, and allows duct thermostats T-3 and T-4 to control the maximum outdoor air damper D-2 and the return air damper D-3. When the fans stop, E-l is de-energized to close the outdoor air dampers and also 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 Automatic Control 883 Remote bulb thermostat T-2, with bulb located in preheater discharge, operates valve V-3 on the preheater coil to maintain a constant preheater discharge tempera ture. On rising temperature, thermostat T-l, in the conditioned space, closes reheater, valve V-l and, through relay C-l, opens face damper D-2 for cooling. On rising humidity in the conditioned space, hygrostat H closes humidifier valve V-2, and likewise, through C-l may open face damper D-2 for dehumidification. : For closer control, the face and by-pass dampers should be eliminated, and cooling means continuously provided whenever the outdoor dew-point rises above a pre determined maximum. Reheating and humidifying may be required to provide the desired conditions. However, such a system will be less economical in operation. . - PANEL HEATING CONTROL j Panel Heating is sometimes designated as radiant heating because the principal portion of this type of heating.is radialed to the body or object THERMOSTAT ' HYGROSTAT DISTRIBUTION Fig. 1. Control Diagram for Year 'Round Air Conditioning System discharge thermostat T-5. Duct thermostat T-6, in the preheater discharge, posi tions preheater coil valve V-l to maintain a constant preheater discharge tempera ture. ! 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 provided that T-l is satisfied. At 65 F outdoor, D-2 will be fully open and return 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 by-pass low limit thermostat T-5, so that reheater coil valve V-3 is operated directly from thermostat T-l. As outdoor air temperature rises from 65 F to 75 F, duct thermostat T-4 gradually closes maximum outdoor air damper D-2 and opens return air damper D-3. Cooling thermostat T-2 positions cooling coil valve V-2 to admit more chilled water as the space temperature rises. Hygrostat H positions humidifier valve V-4 to maintain the desired humidity in the conditioned space. ' . 7. The arrangement of automatic control for a constant temperature and constant humidity air conditioning system, using 100 percent outdoor air, is shown in Frg. 2, and the control description follows: Whenever the fan is running, relay or solenoid air valve E-l, actuated by the fan motor circuit, is energized, opens outdoor air damper D-l, and also permits hygro stat H, in the conditioned space, to control humidifier valve V-2. When the fan stops, E-l closes outdoor air damper D-l and humidifier valve V-2, which is being heated. Automatic controls for radiant and convective heating differ somewhat due to the 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.5 Effect of Inertia of Panel . If a panel has considerable heat storage capacity (as compared with a convector or conventional radiator) it will continue to emit heat for some time after the room thermostat has become satisfied and has shut off the supply of heating medium. This will cause uncomfortably warm condi tions to exist in a space. Also, there will be a considerable delay between fie time the thermostat calls for heat and the time heat is actually de-: livered to the space (because of the large part of the heat that must first be stored in the thermally heavy radiant surface). Whenever inertia exists the source of heat supply, uncomfortable cycling of space conditions will result unless means of anticipating load changes before they occur in tie space, or means of setting the basic energy supply rate from load conditions, are provided. If a thermally heavy radiant surface is used, the primary control should 884 CHAPTER 39 1954 Guide be actuated by outdoor temperature (load) to determine the basic tem perature of the heating medium supplied to the radiant surface. To allow for variations in internal load, an inside thermostat should be used as a high limit to reduce further the heat input, if necessary. If a thermally light radiant surface is used,; controls may be applied in the same manner as for typical convection heating. The terms thermally heavy and thermally light, referring to capacity for heat storage, are comparative and descriptive rather than exact. For example, a concrete .floor panel in a frame structure, without insulation would represent a heavy panel in a light structure. A frame type (metal lath and plaster) panel in a concrete structure would represent -a light panel in a heavy structure.- As indicated previously, a heavy panel in a heavy structure provides comfortable conditions if outside controls are used in addition to the inside thermostat. But if a heavy panel is used in a light structure, rapid changes in outdoor conditions may cause discomfort in spite of outdoor controls, because the structure reacts so much more rapidly than the radiant heating surface. Since thermally heavy radiant surfaces introduce considerable lag in the heating system, it is desirable that a control system be capable of maintaining the lag at a minimum. One method of reducing the lag in heat output is to utilize design water temperature in the panel, thus causing maximum rate of heat from the water in-the pipe coils through the concrete slab to the surface of the panel; and into the space when heat is needed. Satisfactory control can be obtained only if the control system is sensitive enough to regulate the heat output of the panels with sufficient precision to prevent over-heating, and to anticipate heat demand as affected by out side weather conditions. . Circuit Balance ' In addition to a thermostatically controlled device for modulating the temperature of the circulating water, it is advantageous to insert in each circuit a locked flow'control or adjustable resistance to give uniform condi tions throughout all rooms. Owing to unforeseen difficulties with varying frictional losses in pipes, emission factor, and exposures, it is an advantage to be able to regulate permanently the flow through each circuit by means of a key operated valve as indicated in Fig. 3. . Compensation for Increase of MRT . Due to the increase in-MRT (mean radiant temperature) within a panel , heated space, which necessarily takes place as the heating load increases; the air temperature should theoretically be lowered to maintain comfort. In ordinary structures, with normal infiltration loads, the required reduc tion in air temperature is not great arid a conventional fixed control point room thermostat may be used. If a large infiltration load exists, or if un tempered mechanical ventilation is employed, a thermostat with variable control point should be considered. Because of the relationship between' MRT and air temperature in the space (and the variable MRT from point to point in the space) a conventional type of room thermostat (either, fixed or variable control point as previously determined) measuring prin cipally air temperature, should provide simple and satisfactory control. :' Lowered Night Temperature ' In general, lowered night temperatures will produce very unsatisfactory" conditions with any panel healing system. Heavy panels such as concrete" floors cannot possibly respond to either increase or decrease in temperature Automatic Control ; 885 within any-reasonable time.. Light panels such as'plastef ceilings or walls may respond;'with sufficient rapidity to changes in temperature, so>that moderately`satisfactory results- can be expected front lowered 'night'temA peratures: However, very little fuel saving-can be expected-- even with these fight panels. : - ; Typical Control Systems.............. /H T . ., There are many methods of control which are' used^in connection with panel heating systems. Some systems provide continuous circulation of the water and vary the water temperature to counteract variations in the outdoor temperature, space temperature, or a combination of these tem peratures. SeveraTsystems of Control depend upon intermittent circula tion of the water,' either by- intermittent pump operation1 or' the closing and opening of valves, in combination with either- constant water tem perature or with variations in the: water temperature.! i ROOM CONTROL TO MIXING VALVE OR Fig. 3. Panel Heating Control System Fig. 3 shows a typical arrangement of the essential parts of a simple' panel heating system, which has several possible variations, depending upon the equipment used. The heating unit -controls and-safety-devices are not shown; These devices are described under-Residential- Control Systems. ': One system of control-uses a self-contained three-way mixing valve operated by an outdoor thermostat to maintain the water temperature in inverse proportion to changes in the outdoor temperature. - The indoor thermostat stops and starts the water circulator as required to maintain the space temperature. If more than one zone is to-be:-controlled, a separate indoor thermostat is used to control operation of a separate circulator for each zone. - .. - Another arrangement has a' self-contained three-way water-mixing valve controlled by an outdoor thermostat in conjunction with an indoor heatsensitive element. This instrument may be a-blackened-copper sphere perhaps 8 in. in diameter that' ivili' overcome thevoutdoor thermostat in fluence on the mixing valve if the indoor temperature varies too much. Another scheme employs a three-way water mixing valve operated by an electric motor. The impulses from the outdoor thermostat, indoor thermostat and an aquastat in 'the mixed water all are electronically co ordinated to control the mixing valve motor. "' ' Pig. 4 shows a typical electronic control system arranged for circulator Automatic Control 887 operation-.ini cycles. .Heating.unit and, safety controls;, always .essential, are not showni-in;this drawing. The electronic relay coordinates the sig nals from'the room thermostat, the outdoor element, and the return water control bulb so as to vary the .flow of water to the panel heating surface in proportion to the heat demand. When the water in the boiler is,warmer than is required, it is possible to bypass the boiler by manual operation of the hand valves. This manually operable alternative may be useful in new panel systems that have coils covered by plaster, to prevent too rapid drying-out of the plaster. ... ; buildings of limited size, it is possible to consider the entire building as a: single zone. In such cases, as in small residences, a single thermostat is used to control directly the automatic firing equipment, main heating valve, or the cooling equipment. In large buildings the demand for satis factory temperature control makes it necessary to sub-divide the building into suitable zones separately controlled. There are a number of factors to be considered in zoning, in order that heating requirements in a single zone will be approximately consistent' throughout its extent. ' ; individual room control ; ; v 1. Exposure may be a factor to be considered, with particular reference to pre The ideal temperature regulating system for any building is. one that promotes maintenance of a desired temperature in every room at any time, regardless of location and occupancy. . Individual room temperature control, is recognized as the answer to vailing winds, sun effect, and the shelter afforded by surrounding structures and topographical features. 2. Occupancy may be a determining factor, in that the indoor temperature re quirements for the activities carried on in various portions of the building may vary, and the hours of occupancy likewise may differ. 3. The physical characteristics of the building will enter into the subdividing of FLOW TEMP. .THERMOMETER the heating system into zones by reason of the fact that satisfactory temperature conditions throughout a single zone of given extent may not be enjoyed equally in c buildings of dissimilar types of construction. Also, the height of the building and its horizontal extent and form are considerations which must be borne in mind. 4. The cost of the-zone control equipment for such additional zones as might seem ( RADIANT PANEL otherwise desirable, often will influence the decision as to the final number of zones H -1 I i-- tv. vt D to be employed. In buildings of considerable size, accepted practice dictates,that there shall be at least one zone for each exposure, although each exposure very pos cELECTRONIC PRELAY sibly should be sub-divided vertically into two or more zones, for the higher struc tures. Also, the presence of two or more wings, having the same general exposure, AMPLIFIER | TANK may suggest the desirability of more restrictive zoning. When the street floor, or any other portion of the building is used for public occupancy or activities which WATER TEMR H CONTROL BULB LI differ from those carried on in the remainder of the building, it is desirable to provide separate thermostats and controls for each individual area. For zones which have outside exposures, the control for the zone must, & in some manner, respond to the effect of the outdoor temperature, the sun exposure, and the variations of the wind as they effect the temperature and conditions in the zone. Fig. 4. Electronic Control System for Panel Heating Additional Features .>' ' _ '. s; proper thermal environment in schools, hospitals and offices. Demand Provisions may also.be made to maintain a predetermined low economy temperature in each zone during periods of non-occupancy; to facilitate -. for it is increasing, to meet individual requirements in apartment homes;, hotels and separate residences. ,'r j ic quick warming-up following such periods; and to follow those portions of the daily cycle of control with normal heating effect during the occupancy Control of the temperature in each room or possibly of adjacent rooms i period. ';! t having the same orientation (as in an apartment home) overcomes many A control panel, at a central location, may be arranged so that manual- of the problems encountered when attempting to regulate the temperature , of a building as a whole, or of large areas or zones. Each individual ther-: reset switches for each zone may raise or lower the operating temperature. Time switches, if desired, may be provided for obtaining, automatically, mostat regulates the heat input for its particular space regardless of expo-: sure to sun and wind and occupancy. The end result of individual room;"' control is fuel economy and comfort of the occupants. Each room should^ any day-night or other predetermined control program which the operators of the building may desire. The characteristics of the regulators which are have a thermostat that controls valves or dampers on all the controllable ^ sources of heat or cooling effect. One uncontrolled source of heat in.a ' room in which a thermostat controls other sources of heat, or cooling,rtf will lead -to eventual unpopularity of the thermostat or control system. -,jf V\ operated by the zone controllers depend upon which of the basic systems of zone control is employed in a given installation. Shut-off, mixing or throttling valves, and various forms of devices to reset or pilot the action of reducing valves and to control fifing means, are some of the more com mon regulators which are used to control the flow of steam or hot water, ZONE CONTROL ' ' under the command of zone controllers. The characteristics of these Zone control for any heating; ventilating, or air conditioning system ,isr employed where it is desired to control the heating, or cooling effect in ,a-.^ number of rooms or areas, which have similar orientation and occupancyiy.H regulators usually are determined by the manufacturer of the type of con troller which is selected. DESIGN COORDINATION through -one set of controls. Under certain conditions, particularly m ' A heating or cooling plant designed to meet maximum conditions with out regard to controllability, may be unduly costly to operate and difficult i; 888 CHAPTER 39 . 1954 Guide to control. The coordination of the building design with the type of sys tem and arrangement of controls should be considered during tie planning stages. The following considerations are recommended:. , 1. Only groups of areas which have similar load characteristics should be served from a heating or cooling system under the control of a single zone. Rooms or areas having dissimilar load conditions should have individual controls. / The smaller the: controlled .area, the better will be the control obtained and the more nearly will the desirable, individual room control be achieved. . . 2. A system that employs constant air volume with variable air temperature is more satisfactorily controlled than one that requires throttling of air volumes in order, to achieve temperature regulation. ' / 3. Heating and cooling coils should be carefully.selected to avoid oversizirig where light loads can be expected so that accurate temperature control can be achieved without hunting or short-cycling (oscillations from high to low temperatures). 4. Stratification of air in ducts must be prevented where no turbulance occurs after the coils or mixing dampers and;where branch ducts receive air of different tem peratures. : .. : 5. When pre-heat or tempering coils are employed they should be of the internal distributing tube or non-freeze type and in cold climates it may also be desirable to use face and by-pass dampers, with constant steam supply to the coil, in preference to throttling valves for temperature regulation. . 1' 6. Wherever automatically controlled dampers are used, those with adjacent blades opposed rather than parallel to each other will obtain the more uniform dis tribution. .. 7. When the relative humidity of the air is to be controlled it is always desirable to provide some means of reheating the saturated air. 8.. Short-cycling of refrigeration equipment should be avoided by (a) providing capacity reduction or automatic unloading of the compressor to match the minimum load, (b) controlling.the temperature of the condenser water, (c) providing artificial load, or (d) providing storage capacity for the system.7 . (, 9. Good air distribution and adequate diffusion of the air entering a space are necessary. Return air grilles should be located as an aid to proper distribution. Temperature control devices cannot prevent drafts nor cam they be expected to compensate for poor design. .... . .n 10. Radiator valves and valves for heating coils must not be oversized if close control is to be expected. For large capacity services multiple valves should be used. Where two valves are used, one should be sized for and one for % of. tl?e steam requirement, and arranged for sequence operation. 11. Adequate space must be allowed for the equipment. Dampers should not be placed too close to coils and space must be allocated forthe damper operators. Valves and their operators must be accessible for inspection and. attention. Duct thermo stats must be placed in a representative unstratified mixture of the air being con trolled or if this is impossible, long averaging bulbs must be used. Humidifier pap* should be placed down-stream from the source of heat. Coils must not be placed too close to either the inlet or the outlet of fans. , 12. Space controllers must be placed in a space where they will measure the vari ables they are to control and where the condition is representative of the whole space. If the return air duct is used to represent space conditions the controllers should normally be located as near the space as possible. . '' - ; REFERENCES ^ 1. Instrument and Control Manual for Operating Engineers, by Eugeoe'W: F. Feller (McGraw-Hill Co., 1947). ji 2. Automatic Control of Heating and Air Conditioning, by John E. Haines (McGraw-Hill Book Co., Firs* Edition, 1953). -: . 3. Save Fuel for Victory (University of Illinois, Engineering Experiment Station Circular Series No. p. 3i). .` . 4. Modern Air Conditioning, Heating and Ventilating, by W. H. Carrier, R. E. Cheme and W. A. Gran*>. (Pitman Publishing Corp.-1950, Chapter 18). ' . 5. Air Temperature Gradients in a Panel Heated Room, by J. M. Ayres and B. W. Levy (A.S.H.V.B- Transactions, Vol. 54, 1948, p- 131). *. 6. The Application of Storage Refrigeration to Air Conditioning, by C. F. Boester (A.S.H.VJS. Trah*" act7i.oUnsse, VofoCl. o4l5d, A19c3c9u, mp.ul6a7t5o)r.s in the Air Conditioning Field, by B. W. Evans and C. J. Otterholm (A-S- H.VJ3. Transactions, Vol. 48, 1942, p. 123). ' '` . CHAPTER 40 MOTORS AND MOTOR CONTROLS Fundamentals of Motor Selection; Alternating Current Motors, Types and Cont:*ol 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 suitable for vari ous services, is now the most widely used form of prime mover. The equipment for starting, controlling and protecting these motors varies with the type and with the functions it is desired to attain. Motors are divided into two general classifications, alternating-current or direct-current, depending on the power source to be used. , FUNDAMENTALS OF MOTOR SELECTION The following characteristics of the power supply should be determined: (1) whether current is alternating or direct, (2) voltage, (3) alternating current phase, (4) alternating current frequency, (5) voltage regulation, (6) continuity of power. . 1. A-C vs. D-C Systems. For most applications, a-c supply is satisfactory since suitable performance can usually be obtained with a-e motors and control. Where special characteristics, such as an extra wide speed range and severe accelerating or reversing duty are involved, conversion by means of motor generator sets, by rec tifiers, or in special cases by converters, may be.justified. . 2. Voltage. Standard conditions of voltage and frequency are the values listed on the name plate of the motor. Reasonable hprsepower 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 common and nominal system voltages are frequently different. . ^ 5. Voltage Regulation. The voltage regulation of the power supply should be known in order to select motors which will deliver sufficient torque even with the probable drop in voltage, to start and carry the load. All induction motor torques and synchronous-motor starting and pull-in torques vary as the square of the voltage. 6. Continuity of Power. Dips in voltage from switching or other line disturbances ay necessitate time-delay undervoltage protection, and, in case of synchronousmotors, high torque designs and resynchronizing control. Sustained low voltage may necessitate higher torque motors. the following characteristics of the driven machine should be determined: U) mechanical arrangement including position of motor and shaft, porta bility desired, drive connection, and space limitations; (2) speed range de sired; (3) horsepower requirement; (4) torque; (5) inertia; and (6) frequency f starting. ' . .1. Mechanical Arrangement. Arrangement of the driven machine visually deter- nues whether a horizontal or vertical motor is needed. Horizontal motors are more tMerally available and less expensive; most grease-lubricated ball-bearing motors "*11 operate in either position. Fractional-horsepower waste-packed sleeve-bearing 889 890 CHAPTER 40 1954 Guide Table 1. Reasonable Horsepower Design Limits for Standard Motor Voltages Poweb Supply Standard Motob 1 Voltage Suggested Minimum Hobsepowbb Suggested Maximum Hobbefoweb Alternating 1-phase *' ' ; -115 230 1' . ' . . : Alternating 3-phase 110 ' ; 220 .. .. 440-550 2300 . i . 1 4000 4600 6500 ' - . None None None . ' None 1 50 100 250 400 1 15 15 200 1000 7500 8000 None -' motors are satisfactory for sbbrt periods of vertical operation where no thrust is involved.- ; ' If shaft is tilted for momentary operation, special construction of bearing housings will be required for oil-ring-lubricated 8leeve?bearing motors, to avoid loss of lubri cant.. In case of .long periods of tilted operation, bearings suitable for end thrust may be necessary. Ball-bearing motors with grease lubrication are suitable for. tilted operation. '* * Most motors are suitable for mounting with.base above a horizontal shaft or to one side of the shaft, provided the end shields are rearranged. If, during operation, the angle of the motor, (with regard to the horizontal shaft) changes more than 10 or 12 deg, a ball-bearing motor will usually be required. Sleeve-bearing motors are also applicable within the angle given if modified oil gages are provided. ' On portable machines; motors of greater compactness and less weight than stand? ard may be required, and special bearing construction may be needed, except for ball-bearing motors. 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 machine, such as shaft or bearings, are common with the motor structure) a built-in construction may be advantageous. .. . ..j i! ' -- - Belt 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 greater speeds than about' 5000 fpm. Application of flat belting to vertical-shaft motors is difficult. ; >- ,, Chain Drive. The chain manufacture should be consulted so that the best drive; on a basis of quietness and economy of.operation may be selected. Gear Drive. Compactness and arrangement of drive often indicate gear motors,: which are obtainable in a variety of mechanical constructions with speed ratios/of 3 to 1 upwards, and are generally limited to about 75 hp maximum. Where the pinion of ordinary spur gearing is mounted on the motor shaft, two-bearing motors POWEB Supply Single - Phase Polyphas a-c Table 2. Speed Ranges for Various Types of Motors Speed Range ',l' i:.S . .ft{ " Brush-shifting repulsion motor _ , * Capacitor-motor .with topped,winding, Multi-speed capacitor-motor . 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 .' ' Shunt-wound standard contiani-ipeed motor with field control *D-c motor with armature control '. A'djustoble-speed motor*' * .. . Shunt motor with adjustable voltage supply 3:1 2:1 ^ 2 or 3 fixed speed?; \ 2. 3 or 4 fixed speeds ud- 2:1 ` 4:1 ii 20:1 3:1 Very wide range Very wide range Very wide range -n ' 2:1 in some cases Wide From 3:1 to 6:1 Very wide ^ --Soeed regulation relatively wide- Unsuitable for i Motors and Motor Controls 891 are limited in horsepower ratings. Maximum pitch-line speed with steel pinions is about 1400`fpm. '. '" The selection of the motor part of a gear-motor is the same; as for a conventional motor. - . . . Space limitations may affect the choice of motor and require (a) built-in construc tion; (b) a gear-motor; (c) forced ventilation using an external blower; or (d) a small frame with Class B 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 the proper motor rating from a heating standpoint.. In case of extremely large variations in load, or where shut-down, accelerating, or decelerating periods constitute a large portion Of the cycle, the rms horsepower may not give a true indication of the equivalent continuous load, and the motor manufacturer should therefore be consulted. . , . , . Where the load is maintained at a constant value forian extended period (varying from 15 min to 2 hr, depending on the size), the horsepower rating required will usu ally 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 re quired at each speed must be determined. ,' > 4. Torque. The torque, required to operate the driven machine at every moment between initial breakaway and final shutdown is important ip 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 ease of medium-sized centrifugal pumps, or as high as 225 to 250 percent of full-load torque,, as in the case of a loaded reciprocating 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 pos sibility of low voltage and the type of starter used. The torque required after breakaway for acceleration to full speed varies with dif ferent driven machines, remaining at a rather high value, throughout acceleration for such machines 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 tne ac cisc:ierauo--n. The approximate time required for acceleration from rest to full speed where Time in seconds = (rpm) X WR} -5- {T X 308) : (1) (rpm) : full-load speed iu revolutions per minute. T . average torque available for acceleration, foot-pound, WR* = inertia of rotating parts, pound-foot square. ` If the time to accelerate 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 effect WR* of the rotating parts of the driven machine affects the accelerating time and, therefore, the heating of motors and control, particularly where reversing duty or frequent starting is in volved. ' Where synchronous motors are applied, the WR* must be known, Bince the pull-in torque required of this motor varies approximately as the square root of the total of motor and load. The WR* 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.themotor Rhaft by multiplying by [(rpm of rotating member) -5- (rpm of motor)]* (2). j. - frequency of Starting. The frequency of starting the driven machine affects e motor and control by increasing their heating, particularly where accelerating CHAPTER 40 Tabi-e 3. Classification of Motors Type .8?ss Character istics Full Voltage . Starting Starting . Torque., . Current .. -HPRange Constant Speed Drives Application (a) to () Squirrel-cage general' Constant purpose Design A Normal 1-2.5 High 6-8 [times ';' ' times All Squirrel-cage Design] Constant . j. Normal 1-2.5 Normal 5-6 ' times times Medium Small Squirrel-cage Design] Constant High 2-2.5 Normal 5-6 Medium times times Small Wound rotor Constant or High 1-2.5 Low 1-3 variable ' times ' timews (with secondary control) All Synchronous high speed Synchronous- low speed 1 Exactly con stant Normal r, 0.76-1.75 3 Normal 6-7 times times. . Exactly con Low 0.3-4J.4 stant. . times Low 3-4 times Medium Large Medium Large (a) Fans and (c) centrifugal pumps and centrifugal compressors . (a) Fans and centri fugal pumps and centrifu- ' 1 gal compres- ' sors (6) Reciprocating pumps (e) and compressors < started loaded ((bo)) Hoists reciprocating pumps and . compressors . (c) and frequent' (e) or hard start (o) Fans and centri- . fugal pumps - and centrifugal (a) Reciprocating compressors starting un loaded Two value capacitor Constant . High Permanent split; capacitor . Capacitor, start * Constant Constant tow - Moderate . Repulsion Induction Constant High , Normal Normal Normal Normal Split phase Constant < and ad- justable. Normal Normal Small Fractional (b) Pumps and com pressors ' (a) Fans, Blowers ; .a Small Frac (o) Fans and pumps tional.,. Medium ' Small Fractional (o) Fans (b) pumps and compressors r () Fans r () pumps and - - compressors (d) fans--direct 4 _________ Adjustable Speed Drives Squirrel-cage high slip. Transformer adjustment Squirrel-cage sepa rate winding or regrouped poles Wound rotor Variable Constant multi speed Variable Normal Normal Normal or j Normal or high low High 1 Low (inth secondary control) Repulsion Variable High Capacitor low torque Variable tapped winding , . two speed Capacitor low torquel Variable transformer ad juatment Split phase re Constant grouped poles Low Low Normal | Normal Normal' j Low Normal Medium Small' (a) Fans (o) Fans ,;r \ (b) pumps and ; c) compressors Sa) Fans ` b) centrifugal pumps and * compressors ' (o) Fans, centrifug8^ - pumps 1 (b). compressors a?(d) Fans, drect Fractional or rae. cDiprriovceastihnagvpinugmmpesdaiunmd ocor mlowpr-esstsaorrtsinsgtatortreqdueuannlodadineedr.tia (WR*) such as fans and centrifugal pum. p'--. b. Drives having high starting torques, such as reciprocating pumps and compressors started loaded. - c. Similar to (a), except where frequent or bard starting (large WR*) requires a higher starting and accel-/ erating torque, d. Fans direct connected, e. Stoker drives. Ap, Motors and Motor Controls 893 time is prolonged by high iKB1 and high load'torques. : In general, driven machines starting more than 4 to 6 times per hour may. require special motors and control. ALTERNATING CURRENT MOTORS Alternating current motors are divided into-two main classifications: -polyphase and single phase (see Table. 3),' according to the type of power supply. They are further subdivided 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 capacitor starWnduction run single phase motor, for in stance, will cost approximately twice as much1 as the corresponding three phase Design B squirrel-cage motor. In addition, the polyphase motor has the advantages of higher power factor and higher efficiency. Table 4. Locked-Rotob Cubbent of Thbee-Phasb, 60-Cycle Motors . at 220. Volts*- b ; : . i- . HP B, C, AND D :HP B^CAm D Design F Amperes - Amperes. Arepre, . Amperes . 1 or less m 2 3 5 m. 10 15 . 20 25 ' 24c ~ 36 45 60, 90 . . .. ; 30 40 50 . 60 ' 75 120 100 150 . ..' 125 220 : 150. 290 - .200 365 " * ' : 435: ' 580 725 870 1085 1450 1815 2170 . 7900 . .~ 270 360 450 540 675 900 1125 1350 1800 The locked-rotor current of three-phase, 60-cyclerconstant-speed, induction motors, measured with rated voltage and frequency impressed and with rotor locked, shall not exceed the tabulated values. b Locked-rotor current at other voltages shall be.inversely proportional io the voltage. cFor 1 hp or less the value is given.per hp. Polyphase Motors .. . The three types of polyphase motors are:sguirrel-cage induction motora, wound rotor induction motors, and synchronous motora. Squirrel-cage motors are specific 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 motors provide 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 starting .torque with starting current same as Design B, and are used on compressors started without unloadere, and on reciprocating pumps. Design D motors liave high slip* and are used with flywheels for widely pulsating loads on [equipment such as reciprocating compressors and pumps where other motors would draw' high peak currents. '' . Figs. 1 and 2 illustrate the characteristics of squirrel-cage. motors. Both power factor and efficiency are improved if the motors are operating Refer to Glossary at end of chapter. 894 CHAPTER 40 as near rated load as possible. In addition, as shown in Fig. 2, power factor' and efficiency: are better for higher speed motors. 1 ' Wound Rotor motors, are used for applications requiring high starting torque at low starting current, because a wound rotor motor with its con troller and resistance can develop full load torque when ^starting'-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 mpton changes the speed torque characteristics. The motor speed, ^with #- I Motors' and Motor Controls 895 Synchronous motors are used to drivefans, blowers, pumps, Compressors and other applications. Compressor applications having a^highi peak torque require the use of flywheels to smooth out power peaks, and should always! be referred to the electrical manufacturer for recommendations.1 ' Synchronous motors'are provided with built-in damper windings on thb 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 . ;i.: u. 11 h i; ! .4; ; i ' , f r. the resistance added, is dependent on load, and consequently, the motor has very poor speed regulation when secondary resistance is added to reduce the speed values below 50 percent. > Synchronous motors are used for continuous duty applications 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 r when compared 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 charac teristic of all induction apparatus, such as induction motors and neon: signs. Unless synchronous motors or capacitors are installed, the plaid power factor may be comparatively low. This does not 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 embodying 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 equipment.* * Refer to Glossary at end of chapter. MOTOBS , rrl'f 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 f synchronous motor, drives, fisting starting, pull-in, and pull-out torques. Multi-Speed motors provide flexibility in many types of drives. Syn chronous motors can be furnished only with a 2 to 1 ratio in speed, single winding. Squirrel-cage induction motors may be 2, 3 ar 4 speed. ' TwosPeed induction motors are usually of single winding type, having a 2 to 1 ?Peed ratio such as 600 rpm and 1200 rpm, or may be double winding, three-speed induction motors are always two winding, and four-speed Motors and Motor Controls 897. 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 small fan drives. Operation is similar to the capacitor start motor, except that the capacitor is not cut out when running. . Repulsion-Induction motors develop high starting torque. The motors have two rotor windings--a squirrel cage for running and a wound rotor connected to a commutator for starting. No switching device.is.required to change from starting to running winding as this is accomplished by a gradual shift with speed in the magnetic flux path,.so that near rated speed the motor operates completely on the squirrel cage winding. Repulsion Start-Induction Run motors are similar to the repulsion^ Single Phase Motors jl J Single phase induction motors have auxiliary windings or devices starting, and are classified by the method used. Capacitor, start motors develop high starting torque in fractional horsey power ratings, and moderate starting torque in larger ratings. They used for constant speed drive such as fans, blowers-and centrifugal punifej-^ During the starting period, a winding with a capacitor in series is connect*# to the motor circuit and when the motor comes up to speed, a centrifugate;, switch cuts the capacitor and second winding out of the circuit. Two-value capacitor motors develop high starting torque employing#^ starting capacitor and a running capacitor. The starting capacitor give^ high starting ability, but is suited for short time operation only, and ls'egig^ out for the running condition by a centrifugal switch. The running cj*^ pacitor gives high efficiency at full speed. These motors are used induction motor, but they have only the commutator winding. They are supplied with a centrifugal short circuiting switch which shorts the com mutator bars when the motor comes up to speed to obtain a winding ap proximately like the squirrel cage in its function. Repulsion-Induction and Repulsion-Start-Induction Run motors are suit able for applications, such as industrial compressors, requiring high1 break away torque, and where commutator and brush noise are not factors. Split Phase motors have a high resistance auxiliary winding which is m-the circuit during starting, but is disconnected through the action of a centrifugal switch as the motor comes up to speed. Under running con ditions it operates as a single phase induction motor with one winding in the circuit. These units are available for the small horsepower ratings, Mid when equipped with a high slip rotor, may be used for adjustable 898 CHAPTER 40 1954 Guide varying; speeds through line voltage control. The motore. are'ideally suited for fan duty. Speed-torque characteristics of single phase motors are shown in Fig. 3. 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 areas, power companies check carefully the starting; currents-in order to prevent objectionable voltage dips. This is particularly important for motors started frequently, such as those con trolled by pressure or temperature sensitive'devices and applied to re frigerators, stokers, oil burners and water pumps. . The report of a joint committee of AIEC-EEIvNEMA* recommended three application rules taking into account the greater annoyances re sulting from frequent motor, starting during lighting hours against infre- Table 6, Recommended Single Phase Motob Ratings fob Full Voltage Starting " HP Rating Locked-Rotor Current* at 25 C Amperes General Use (Rules 1 <fe 2) Special Conditions (with Utility Permission) (Rule 3) 230 V , 115 V 230 V 115 V : 230 V Ho H H H H H 1H 1H 2 3 5 io A-M 10 A-M 10 A-M . 11.5 A-M 31 15.5 M 45 22.5 M 61 30.5 70 35 40 s 50 70 100 A-M A-M A-M A-M A-M A-M M M M M . A-M A-M A-M A-M A-M A-M A-M A-M A-M A-M A-M A-M A-M A-M A-M A-M A-M A-M A-M A-M A refers to automatically controlled devices. . M refers to manually controlled devices. * These values of Locked-rotor current are the t motors. . .' . . j the'NEMA standard for single-phase Design M quent 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 twice these values when manually con trolled (usually infrequent 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 refrigerators, 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 starting switches are riof 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 Refer to Glossary at end of chapter. Motors and Motor Controls 899? to be the operating current in amperes, when the compressor. is. deliver ing rated output.; . . The motors for hermetically enclosed service are usually of the splitphase type or of the capacitor-start (or two-value capacitor) 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 prediction of the amount of time delay required to bring the motor up to speed. ACROSS THE LINE STARTING REDUCED VOLTAGE STARTING Arrangements 2, 4 and 5 provide automata c push-button starting. .. : Fig. 4. Recommended Controls for Squirrel-Cage Motors : - / The second method of starting split-phase motors utilizes a series-coil or current-operated relay. This device is affected indirectly by motor speed. . . In this 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 dose, 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 corre sponding to a pre-selected speed, the magnetic force of the coil diminishes to a point which allows the contacts to open, removing power from the starting winding. . Capacitor-start and two-value capacitor hermetically sealed motors are visually started with a voltage-type relay. In this method of starting the relay coil is connected in parallel with the starting winding. When .power 's 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 corresponding to a pre-selected speed, tile relay operates and opens its contacts, thereby opening the starting CHAPTER 40 winding circuit. The relay then keeps these contacts open because there is sufficient voltage induced in the starting winding, when /the motor is nirlningjj to hold the relay in the open contact position. CONTROL FOR ALTERNATING CURRENT MOTORS : Squirrel-Cage motors are usually linestarted where power company limitations permit. In sizes up to 5 hp at 220 volts, or 7\ 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 either of manual or push button controlled magnetic type; - In specifying this type of starter, consideration should be given to., the fact that starting torque of squirrel-cage motors varies as the square of the applied voltage. For example, a motor developing 100 lb-ft starting ilNATION STARTER Motors and Motor Controls 901 In applying reduced voltage starters to synchronous motors it'should be remembered that, since these motors arc started on damper windings and function during the acceleration period similarly to squirrel-cage motors, the starting torque varies as the square of the applied voltage. Consideration should be given to insure development of sufficient motor torque to accelerate the load. Multi-Speed control may be either manual or magnetic, and at full or reduced voltage. When using- automatic magnetic control with two-, three-, and four-speed separate winding or consequent pole motors, con trol 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 depressing the correct push button. This is known as selective speed, control. It is commonly used in the smaller theater installations where the fan and motor are located backstage and the speed control is located in the lobby. : Ii 1o-1i REGULATING '49 J CONTROLLER 01 UNIT ASSEMBLED CONTROL Fig. 5. Recommended Controls tor Wound Rotor Motors . Jf? torque on full voltage would produce only 25 lb-ft torque on starting, on half rated voltage. Fig. 4 illustrates recommended control practice for squirrel-cage motors. fl; Wound Rotor motors require control of both primary and secondary circuits. The primary* control may be the same as for squirrel-cag;lg motors, manual or magnetic, at full voltage. Secondary* control prqjpj? vides means of varying secondary resistance for starting and speed control.^ The secondary controller should be specified for starting duty only, or for, r/? speed regulating duty. If the secondary controller is to be 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 specif fied. Fig. 5 illustrates recommended control practice for wound rotor ^ ^ motors.. . if ` Synchronous motor starters should provide pull-out protection, autoj^/j, matic synchronization or automatic stopping of the motor after pull-out, and insurance of complete starting 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 g field control, but require hand operation for closing the line contactors to'./Vi start and transfer to full voltage. H J 'x * Refer to Gloesary at end of chapter. Arrangements 2, 3 and 4 are optional for motors up to 7J4 hp. 220 volts. Fig. 6. Recommended Controls fob Single Phase Motobs ` Multi-speed motor controllers may be provided with compelling relays which make it necessary for the operator to press the first speed button before regulating the motor to the desired speed. This insures 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 a linestarter, either manual or magnetic. In some cases it is desirable also to provide a dis connect switch. Fig. 6 illustrates the recommended controls. MOTOR RATING The rating of an electric motor depends upon the total temperature which the motor attains under operating conditions. This total tempera ture 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 i*" (902 CHAPTER 40 1954 Guide ibe.,restricted. Improper selection of motors with regard to temperature -ratings, may result in high motor operating temperatures and accompany ing, reduction in .motor life. . > In general, the electrical insulation is the portion of the motor most susceptible to injury from high operating temperatures. Of the several types of insulation which are available, the most common type, specified as Class A by the National Electrical Manufacturers Association, consists of cotton, felt, papier or similar organic materials, and permits a 55 C rise in temperature over a 40 C ambient temperature for totally enclosed motors. Class B insulation consists of mica, asbestos, fiber glass, or similax inorganic materials, and permits a 75 C rise in temperature over the 40 C ambient for totally enclosed motors. Other types of insulation, such as ! silicone resin, are available and permit much higher operating temperatures. " )i. The.mechanical construction of the different types of motor enclosures, and the rise in temperature with Class A insulation for each type, are enu merated in the glossary at the end of this chapter: Since the difference between the hottest spot and the maximum observable temperature, as ' measured by a thermometer, is greater for an opien machine than for an en closed machine, the permissible temperature rise is 50 C for an open motor. FUNCTIONS OF CONTROL EQUIPMENT FOR MOTORS In general, control equipment for all types of motors should provide (1) means of disconnecting the motor from the power supply, (2) means for starting the motor, (3) overload protection for the motor, (4) protec tion against 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 designed for full voltage starting. The i: starting inrush current, however, is limited in many cases by regulations ; of power companies because of the voltage fluctuations which may be i 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 cur- . rent for any given location. The choice between full voltage and reduced voltage starting is governed 7 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 obtained by use oh- 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 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 protect 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 condi- 7 tion is ended. The second type, called low voltage protection, causes the motor line contactor to drop, out on low voltage, but prevents restarting 7: ^'7 -- Motors and Motor Controls 903 when the voltage returns to normal except by the action: of am operator. This latter type of protection is desirable where it is necessary for the operator to makernitial starting adjustments on-the machine. Manual control for ah 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, small 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 devices. An added advantage of auto matic 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 device. GLOSSARY V General Definitions .. NEMA is the abbreviation for the National Electrical Manufacturers Association. AEIC is the abbreviation for the Association of Edison Illuminating Companies. EEI is the abbreviation for the Edison Electric Institute. . Speed Regulation (d-c motors) is the change in speed between no-load and full load, expressed in percent of full-load 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 regulation of 5.26 percent. - Slip (a-c induction motors) is the difference between the motor speed and syn chronous speed expressed in percent of synchronous speed, e.g., 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 case 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 trans former or motor. In the case of the wound rotor motor the secondary is the rotor winding. . ' .: ' NEMA Classification of Motor Enclosures : Open motors (40 C rise, rated load, 50 C rise, service factor load), are self-ventilated ^machines having no restriction to ventilation other than that necessitated by me chanical construction.' ............. ; ' ." ' Protected, motors (50 C rise) have all ventilating openings in the frame protected by perforated covers. .. Semi-Protected motors (50. C rise) have the ventilating openings in the top half of,the frame, only protected by perforated covers. ` ' ... Drip Proof motors (50 C rise) are so constructed that drops of liquid or solid par ticles falling on the machine at any angle not greater than 15 deg from the vertical, cannot enter the machine either directly or by Btriking and running along a hori zontal or inclined surface. \ .. ' ' *; Splash Proof motors (50 C rise) are so constructed that drops of liquid or solid ^articles falling on the machine or coming toward it in a straight line at any angle 904 CHAPTER 40 1954 Guide not greater than 100 deg from the vertical, cannot enter the machine either directly or by striking and running along the surface. ~ Totally Enclosed Non-Ventilated motors (55 C rise) are so constructed as to pre vent exchange of air between inside and outside of the case, but are not air tight and are not equipped with external cooling means. ' ' . ' Totally Enclosed Fan-Cooled motors (55 C rise) are similar to totally enclosed, noirventdated machines, except that exterior cooling is provided by means of a fan or fans integral with the machine. : :v Explosion Proof motors (55 C rise) have an enclosing case designed to withstand an explosion of a specified gas or vapor which may, occur within it, and to prevent the ignition of the gas or vapor Btirrounding the motor by sparks, flashes, or explosions of the gas or vapor which may occur within the machine casing. ' ' - . Dust Explosion Proof motors (55 C rise) have an enclosing case designed and'con- structed so as not to cause the ignition or explosion of an atmosphere of the specific dust, or to cause ignition of dust on or around the machine. (Proper overload pro tection and cleanliness are required for successful operation). .; Water Proof motors (55 C rise) are so constructed as to exclude water applied in the form of a stream from a hose. : Dust Tight motors (55 C rise) are so constructed that the enclosing case will ex clude dust. :' Motor Speed Classifications . A Constant Speed Motor is one in which the speed remains practically constant with changes in load; e.g., a d-c shunt wound motor or a-c squirrel-cage motor with low slip. A Varying Speed Motor is one in which the speed varies with the load, usually decreasing when the load increases; e.g., a d-c series motor or an induction motor with large slip. An Adjustable Varying Speed 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; e.g., a shunt Wound d-c motor adjusted by armature resistance control. An Adjustable Speed Motor is one in which the speed can be varied gradually over a considerable range, but when once adjusted remains practically unaffected by.the load; e.g., 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 150 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 stand ard 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 recognized 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 ana 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 preceding 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- v 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 ma- -;, chines. Motors may also be supplied with flush plate mountings, suitable for close1 _ coupled pump and similar applications. ' CHAPTER 41 SOUND CONTROL Unit of Noise Measurement/Apparatus for Measuring Sound, General Problem, Kinds of Noise, Noise Transmitted Through Ducts, Design Room Noise Level, Noise Generated by Fans, Natural Attenuation of Duct System, Duct Sound Absorbers, Air Supply Noises, Cross Transmission Between Rooms, Controlling Vibration from Machine Mountings IN ventilating and air conditioning a building or a room, consideration must be given to the effect of the mechanical system on the acoustics of the space conditioned. It is important to consider also that the use of air conditioning often permits keeping the windows closed, thus giving relief from certain external noises, but at the same time increasing the necessity of providing adequate sound control. It is assumed that in'a given space the architect and acoustical engineer have produced a room or rooms which are satisfactory for speech, music, or other uses. The ventilating engineer's sole function is to ventilate and air condition these rooms properly so that they will be physically comfortable without adding any acoustical hazards. UNIT OF NOISE MEASUREMENT According to ah international standard, the decibel (db) is the unit for expressing sound pressure levels. The sound pressure level, in decibels, is given by the relation: . . di-!01"`"(o-Ss) ' where P = the Bound pressure in dynes per square centimeter. The reference pressure (0.0002 dynes per square centimeter) is a sound pressure which is slightly less than the threshold of audibility,. at the frequency of 1000 cycles per second, for the person of average hearing. This reference point is approximately the minimum sound pressure that would be audible in a very quiet room to an observer having acute hearing. The ear is essentially a pressure operated device; hence, the sensation of loudness, or magnitude of sound is governed by the sound pressure existing at the point of reception. The sound level meter measures sound level pressure, the measurement being expressed as sound level on a decibel scale with zero corresponding to the reference pressure of 0.0002 dynes per sq cm at 1000 cycles. In the higher ranges of the decibel scale, approaching 120 db, the sensation is one of feeling, and at higher levels the sensation becomes painful. . Associated with sound pressure level is the sound intensity level, expressed decibels above a standard reference intensity. Sound intensity is the average rate of sound energy transmitted through a unit area normal to the direction of propagation, commonly expressed in watts per square centimeter. The sound intensity level, in decibels, is given by the relation: 905 906 CHAPTER 41 1954 Guide < = i0,g-(^r,) (2) where I -- the sound intensity'in watts'per square centimeter. The reference intensity ..is;-10rl6watts; per. square centimeter, coinciding with the reference pressure of 0.0002 dynes per sq cm or 2 X 10-4 microbar. A microbar is the unit of pressure commonly, used in acoustics, one micro bar being equal to one dyne per sq cm. : ... . The relationship of the decibel scale, to sound pressure and sound in tensity is shown,,in Table 1. A stated sound level in decibels, under standardized procedure, will thus be related to a,threshold 010.0002 dynes per square centimeter, or to a threshold of 10-16 watts per sq cm. The standardization upon terminology, procedures and reference levels may be found in Standards1 published by the American,Standards Association. . APPARATUS FOR MEASURING SOUND ' . , The measurement of sound or noise is conventionally made by means of a sound-level meter2 consisting of a microphone,: an amplifier, a variable attenuator, weighting networks, and an indicating meter, which reads directly in decibels. The approved sound-level meter,must comply with . the specifications of the American Standard for Sound Level Meters for ' - Measurement of Noise and Other Sounds, Z24.3-1944, approved and published by the American Standards Association. The meter,is designed to indicate sound level above the standard reference level. Three measur ing networks are generally provided: (1) flat response, (2) 70 db network and (3) 40 db network. The-various networks, are approximations of the equal-loudness contours relating intensity and frequency sensation response of the normal human ear.1' Where there are no specific codes which specify the particular network to be used, general'practice would indicate use of the 40 db network for sound levels up to about 55 db', the 70 db network for sound levels from about 55 db to 85 db, and the flat response network for higher levels. When sound level measurements are stated, the specific weighting network used, i.e., 40 db, 70 db or flat response, should always be reported. Complexity in design and calibration, and variations in component parts of the sound level meter impose some deviation from design objective response. Allowable''deviations in response or accept able tolerations recognized in the Standard, vary from 2 db in the 1000 cycle range to 5 db, or more, below 100 cycles arid above 1200 cycles per second. ,, , ;: GENERAL PROBLEM OF SOUND CONTROL The problem confronting the'air conditioning engineer is to design a system which will operate without increasing the'noise level in the con ditioned space. It is therefore necessary: 1. To determine the noise level existing without the equipment. . 2. To ascertain the noise level which would exist if the equipment were installed without sound control. '' 3. To provide as a part of the installation, sufficient sound control appliances and treatment to reduce the sound level due to the installation to a sound level at least three decibels, and preferably five decibels, below that found in Item 1. To accomplish this the engineer should have information of three kinds: 1, A knowledge of the noise levels currently considered acceptable in various rooms, in order that he may have a basis on which to proceed. 11 Sound Control 907 Table 1. Decibel Scale vs. Sound Pressures and Sound Intensities ' Decibel Level ' 'Pressure f !dynes per sq cm watts . Intensity per sq.cm. Decibel Level . ' Pressure . dynes per sq cm 0 0.000200 ! 1.000 X 10^" .... .40 . 0.0200 i 0.000224 1.259 X 10-" 50 2 0.000252 1.585 X 10-" 60 0.0631 0.200 3 4 0.000282 0.000317 2.000 X 10-" 70 2.520 X 10-". 80 r. 0.631 2.oo 6 8 0.000399. 4.000 X 10-" 90 0.000503 ... ;6.310 X ,10-," . 100 6.31 . . 20.0. 10 0.000631 1.000 X .10-" 'no `63.1 ' 20 30 0.00200 ' ' 1.000 X 10-" 1 120 0.00631 -i 1.000 X 10" 200.0 Intensity ; watts per eq.cm 1.000 X, 10-" 1.000 X10-n; 1.000 X 10-" 1.000 X 10- 1.000 X 10- 1.000 X 10-1 1.000 X 10~ 1.000 X 10-* 1.000 X 10-* 2. A knowledge of the nature and intensity of the noise created by the various parts of the equipment. \ 3. A knowledge of how, when necessary, to vary and control the'noise level be tween the equipment and the conditioned, space. In addition, the engineer should have sufficient information to predict the levels produced by-.noises which may. be transmitted by the duct system from one conditioned space to another, or from an outside space to the conditioned space. In either case, the designer must know the prob able noise level at the point where the noise originates. From this he can compute the attenuation or transmission loss required , in order to bring this level down to that required in the conditioned space. If there is likelihood of direct transmission through a duct,: the attenuation required may be computed as shown in section Noise Transmitted Through Ducts. If the trarismissibn is through dividing wallsj it will be necessary to refer to published data on losses through standard budding constructions.8 Information concerning the sound levels created by ventilating and air conditioning equipment such as fans, motors, air washers and similar items, has not yet1 beferit ^completely established; However, numerous manufacturers are in a .position to supply such data for. many , of their products. Additional information is being collected. Uniformity. in method of test arid presentation of sound measurement data for fans, has been standardized in. the Sound Measurement Test Code for Centrifugal .and Axial Fans, developed by the National Association df Fan Manufac turers. The Code prescribes that the sound level shall be measured by the flat response network of the sound-level ineter. Readings on the 40 db. and 70 db networks may also be taken and reported, but' the'flat response reading is required to comply with the Code requirement. General-prac tice is to use the slow or damped needie reading of the meter. The./asf or undamped needle of the-indicating meter generally reads one to two db lower than the slow or damped meter needle. The same Code prescribes a method of determining the sound level reading at each of-seven stations, spaced at 5 ft'from the'Outside of the fan housing, and located in a hori zontal plane passing through the fan shaft. The sound level of the fan ls the average of the seven readings. The level so determined is valuable Primarily for comparative purposes rather than absolute values. Of more Value to the design engineer would be the sound level at the fan outlet and at the beginning of the distribution duct system. < . The technique of sound measurement in a moving air stream of ap- 908 CHAPTER 41 1954 Guide preciable velocity has not yet been mastered, although it is a subject of current investigation. Development tests indicate that the'sound level at the fan outlet is in the order of 10 to 15 db higher than the average value determined by the seven-station traverse around the fan. Where sound treatment of a distribution duct is required, the initial level should be taken as approximately 12 decibels higher than the reported Code rating sound level. KINDS OF NOISE In solving a sound problem, it is desirable to consider, separately, the several means by which noise reaches the room. This avoids to some ex tent the necessity of knowing the noise level at the source, and instead, places the emphasis on' ascertaining the level at the point where the sound enters the room. The noise introduced into a room or building by ventilating or air conditioning equipment may be divided into two general kinds, depending on how it reaches the room: 1. Noise transmitted through the ducts. . From equipment such as fans, motors, pumps, sprays, etc. . 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 sys tem. /. Noise produced by the grilles. 2. Noise transmitted through the building construction. . From machine mountings as vibration. . From equipment through room wall surfaces. The next step in the solution, of this problem is to present data and discuss methods whereby solutions of 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 TRANSMITTED BY AIR THROUGH DUCTS , Operation. of an air distribution system results in the generation of noise which may be transmitted by air through the ducts to the ventilated or conditioned room. The transmission of this noise may be controlled by the proper application of sound absorptive material within the ducts. The application of the absorptive material is a problem in balancing the, room noise level requirements against the intensity of the noise generated. The four steps in the problem are: 1. Determination of acceptable room noise level resulting from the operation of. the equipment. ` 2. Determination of noiBe level generated by the equipment. . ' Add 5 decibels to the difference between items 1 and 2 to obtain the overall noise reduction required between the equipment and the room. In the discussion which follows, reduction of noise will be referred to as attenuation of noise. 3. Determination of the natural attenuation of the duct Bystem. . 4. Selection of the proper sound treatment for the duct system. >,i. The difference in decibels between the overall attenuation required and the natj ural attenuation (3) is the additional sound attenuation to be provided by absorb^', tive materials installed in the duct system, or by special constructions designed to,,. absorb sound. Experience has shown, for example, that where ventilating require ments permit, introduction of an expansion chamber or a change in area in the duct, will frequently provide further reduction in low frequency noise. : Sound Control 939' Table 2. Typical Sound' Levels* Weighted Network Response Roohs Sound Level in Decibels to be Anticipated Min. Represent ative Max. ' Sound Film Studios----------- Radio Broadcasting Studios 10 Planetarium ........................... 15 Residence, Apartments, etc. 33 Theaters, Legitimate........... 25 ' Theaters, Motion Picture..! 30 Auditoriums, Concert Halls etc. 25 Churches...,......... :!....................... ................................ . 25 Executive Offices, Acoustically Treated Private Offices! 7 30 Private Offices, Acoustically Untreated . 35 General Offices....... ................................... 50 Hospitals................................ .................... Class Rooms................................................ 25 30 Libraries, Museums, Art Galleries........ 30 ' Public Buildings, Post Offices, etc..... Court Rooms................... .......................... 45 30 \ Small Stores.......................... 7,................ Upper Floors, Department Stores............. 7.'....----- - Stores, General, Including Main Floor Dept. Stores... Hotel Dining Rooms......... Restaurants and Cafeterias Banking Rooms..................... Factories.............. .................. Office. Machine Rooms......... 50 40 50 50 65 60 14 14 20 40 30 35 30 30 38 43 60 40 . 35 40 55 35 50 50 ' 60 50 60 55 - 77 . . 70 20 20 25 48 . . 35 40 40 35 . 45 50 70 55 45 45 .60 45 .60 55 70 60 70 60 90 80 .. Vehicles Railroad Coach .. Pullman Car.......... Automobile........... Vehicular Tunnel . Airplane .................. : 60*- 50 75 70 80 65 = 75 65 . 80 85 95 80 90 . * These values are tentative. More detaUed measurements'by D. F. Seacord, Bell Telephone Labora tories (Journal Acoustical Society of America. Vol. 12, pp. 183-187, 1940) give average values aDd standard deviations of room noise in residences, offices, stores, factories, etc., in large American cities. . . .. * For train standing in station, a level of about 45 db is the maximum which can ordinarily be tolerated.' DESIGN ROOM NOISE LEVEL Measurements of sound levels in various types of rooms and locations have been observed by numerous investigators. However, close agree ment upon these values has not been realized, and more detailed measure-. ments are needed to accurately establish the normal sound levels in occupied spaces and enclosures subject to sound analysis and control. Typi cal sound levels, of a tentative nature, based upon earlier determinations, are listed in Table 2. The ievels listed are weighted levels by the 40 db or 70 db network, depending upon the range of level existing! Levels taken upon the flat response network may. be from 5 db to 20 db higher, as governed by the;predominating frequencies which may influence the weighting level. Table 3 lists sound levels based upon more recent surveys than Table 2, and upon the basis of the flat response network. The flat response net work offers a more logical correlation of space sound level to fan sound level which, under present practice, is reported upon basis of the flat response reading. . The values listed were determined with the air conditioning or ventila- 910 CHAPTER 41 ' 1954 Guide Table 3. . Average Sound Conditions.in Various-Types op Rooms and . 1. .Buii-dings* , ,j Flat Response Network . - Type of Room or Building Decibels 20-30 (very quiet) Residences, churches, libraries, apartments, auditoriums, execu- '40-55 (quiet) . . Hospitals, court rooms, quiet offices, show rooms, small retail ' .. . 45-60 stores, tea rooms, hotel dining rooms, foyers, upper floors of ' . (moderately (quiet) Banking 'rooms, beauty, salons, ;barber,,shops, general offices, , . 55-70 restaurants^ main floors of department stores, cocktail lounges, , ; (average) dairy bars, tap rooms, billiard halls............................................. : Gymnasiums, transportation waiting rooms, drug stores, grocery stores, cafeterias, super markets, recreation hallsi* post offices, swimming pools, locker rooms, garages, service stations, dance . halls, laundries, dry cleaners, bowling alleys........... .................. 65-80 .(moderately noisy) Warehouses, office machinery, field houses, hangars, skating rinks, loading platforms, packing plants, factories, machine shops, foundries, forge shops, round houses, steel mills........ . 75-100 (noisy) . * Values based on recent surveys. ' tion equipment out of operation., unless such equipment presented no- acoustical addition to normal conditions. The windows and doors were' closed to simulate the conditions of normal occupancy. In Table 2, minimum, representative and maximum levels are given for each type of- space, classified as shown in the following paragraph. In Table 3, the? minimum to maximum range is shown, with the same general classification?! Minimum sound level refers to spaces within well-constructed buildings,/ typified by double windows, carpeted floors, and acoustically-treated walls, and ceilings. In such spaces heavy upholstered furniture is also usually used. . ' ' ' : . .. V,.- '/ ' Representative sdund:;level^ refers to spaces within average, construction^ ' with average furnishings, and exposed, to external sounds typical of the' locality in which the space is usually found. ' Maximum sound level refers to (1) any space within inexpensive con--' struction where bare furnishings are used, and where noise is normally not *' an important factor, or: (2) spaces in close proximity to very intense street;)- traffic or industrial noise. : 1? 1 i:!l- 'In general, if the sound level in the space resulting from the operation'1, of the air conditioning equipment Only, is equivalent to, or less than, the..?, typical level (from Tables 2 or 3 or, better still, determined by actual site^\ measurement) the installation will prove satisfactory. If the space level^ and the equipment level are equal and heard together, the resultant level'"' will be 3 db higher than either space or equipment level alone. However,J'; to minimize possible annoyance due to introduction of single or distinctive ' frequency components from the equipment, it is desirable to design for an?2t equipment sound level of at least 5 db below the typical space level. -'"'C NOISE GENERATED BY FANS .-iK Noise generated by fan wheels may be divided into two classifications'^ rotational noise and; vortex noise. The rotational noise* may be described Vr Sound /Control 911 as that due.; to the thrust and torque applied to the air. Vortex noise is that due to the shedding of vortices from the blade, and is dependent on the angle of attack, velocity, air, turbulence, and blade ishape. Vprtex noise is due to pressure variations on the blade as a result of .variations of air circulation. Given the noise level at ;the outlet or inlet of,one type, of fan construction under specific, conditions of size, tip. speed, and total pressure, the noise levels at other values of tip speed, total (pressure, and size may be approximated by the relationships: . ,) . , 1. For constant size and.point of rating, the noise level of a fan will increase with increasing speed. .' v; . , ^change) 50 logo ^...... ,, (3) . 2. For constant pressure and tip speed, the noise level of a given type of fan will increase with increasing fan size. -- : : di (change) = 20logij^g^^^ . ; (4) Fan size refers to wheel diameter, housing height or some dimension that is di rectly proportional to linear units. Fan sizes based on arbitrary systems or systems of preferred numbers, have no significance. . Tbe noise of a given fan is not constant at constant speed if the air delivery changes due to change of resistance. In gereral, a backward curved blade fan is lowest in noise at or hear the point of maximum effi ciency; a forward curved blade fan at or between the point of maximum efficiency and shut-off; an axial flow fan at or between the point of maximum efficiency and free delivery. The noise level of a double width fan may be taken as 3 db higher than for a similar single width fan operating under the same conditions of speed and pressure. The sound level characteristic curve of a typical ventilating fan of the centrifugal multi-blade type is shown in Fig. 1. The accented portion f the curves denotes the range of minimum sound emission. The selec tion and application of the fan should be made within such good applica-. won range where quietness of operation is of major consideration. The yarious types of fans available possess individual sound level characterlst'cs throughout their range of possible operation. Recourse to standard 912 CHAPTER 41 1954 Guide Sound Control 913 Fig. 2. Sound Level Characteristics op Typical Vaneaxial Fan test rating information should be made to arrive at the sound emission of - a particular type. .0 In general, that size of fan which is so selected as to operate at or near' peak static efficiency, will also provide the lowest sound level attainable., with the particular type and design of fan. The characteristic trend of the sound level curve of a typical vaneaxial ' fan, adaptable to moderate pressure ventilation- requirements, is shownfin.V Fig. 2. The sound level of a particular fan is primarily governed by the' operating speed required to produce a desired delivery against the systems static pressure. Fig. 3 illustrates the variation of fan sound level in deriff bels with operating speed, the fan operating in connection with a conven-.f tional fixed system. The influence of high static pressures is evident in - increased operating speed and higher sound level. -" The range of sound levels to be experienced in fan application is wide- spread due to volumetric and pressure requirements which extend overs/-broad field. Fig. 4 illustrates the general scope of sound levels of centris t ugal ventilating fans over a wide range of volumetric capacities and static/; ' .. - .`VSI-V ' Vs ';1j- ' : j`> ` tfU ill?;-. Fig. 3. Relation op Sound Level to Operating Speed op a CentrifVo-**'?. Ventilating Fan ' XT.. pressures. The sound levels are based upon a general average of the sound emission that can be anticipated from the several types of fans adaptable to ventilating and air conditioning duties. The sound levels are typical of the centrifugal fans as a class, and specific types may exhibit sensible de parture from the charted values. Exact application should be based upon applicable test data derived from the particular equipment under consi deration. NATURAL ATTENUATION OF DUCT SYSTEM Straight Sheet Metal Ducts. The attenuation of sound in straight sheet metal ducts is a function of the length, shape, and size of the duct.* Attenuation values are given in Table 4. In general this attenuation is so negligible, except for long runs, that it may be disregarded for all practical purposes. . Elbows and Transformations. Due to reflective interference, attenuation will take place at elbows and transformations. The magnitude of the attenuation will depend, on the size and abruptness of the elbow or trans formation as shown in Table 5. When the area of a duct increases abruptly, an attenuation of noise level takes place in the duct. In duct design practice the total area of the branch ducts is greater than the supply duct.. Similarly with outlets, the area of the outlet, plus the area of the duct after the outlet is greater than the duct area before the outlet. Therefore in an outlet run, attenua tion occurs in the duct as it passes each outlet. Table 6 gives the db reduction for various ratios of total branch duct and outlet area to supply duct area. Grilles to Room. The large abrupt change in area between the grilles and the surfaces within a room results in an appreciable noise attenuation. Table 4. Attenuation in Straight Sheet Metal Duct Runs Small___ Medium., wee.._. Duct Sizb, In. 6x6 24x24 72x72 Attenuation pbs Ft. db 0.05 A Al 5VS/r - 91:4` CHAPTER 41 '1954 Guide Table 5. Attenuation op Elbows* "i / ! Elbow . 8lZB lN.b ! ' Attenuation ; per Elbow, db Very small.............. ;............................................................................... ...... Small............................................................... ;...................................... ................ Medium....................... ................... ...................................................... ... Large........................................................ ................................................................ 2 wide 3 to 15 15 to 36 36 plus . ; ' , . 3 2 1.5 1 * The attenuation in v&ned elbows should- be considered the same as in elbows having the same dimen- aions as the radius of'curyatuic of the vanes. If the vanes are lined for the.purpose of damping any vibra- tions in them, one third may bfe added to the attenuation values listed.- : \ b These attenuation values are based on elbows having'a center line radius l.;to 3 times the diameter or width of the duct.; The attenuation'will be greater if the ratio is less than 1.6 and less when the ratio is greater than 2. !' :' .' ' . 4 * This.attenuation is a function of the total grille area (supply and return) and the total sound absorption of the room in satins. (The sound absorp tion of a room in sabins is the summation of the products of each surface of the room measured in square feet multiplied by its corresponding absorption coefficient. The sabin is a unit of sound absorption equivalent to the absorption of one square foot of a totally sound-absorbent surface). The attenuation is given in Equation 5 as: . ,,, , , ., ' ,,/Attenuation between \ ( grilles and room / , Total Room Absorption m Sabins Total Grille Area ... . Values in Table 7 approximate the attenuation for various rates of air change, and general types of room surfaces. DUCT SOUND ABSORBERS The difference between the required sound attenuation and the natural attenuation must'be supplied by the proper sound treatment of the ducts.1 Selection of the Absorptive Material ;ig When a sound wave impinges on the surface of a porous material, ai vibrating.motion is set up within the small pores of the material'by the alternating sound waves. As the ratio of the cross-sectional area of the- pores to their interior.surface is small, the resistance to the movement of; . air in the pores is large. 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 selection and application of the absorptive; material;; - the following points should be considered: ' ;.t Table 6. Attenuation at Duct Branches or Outlets Ratio Branch Duct -f Oim.gr Area Supply Duct Area 1.00 Sum op Branch Areas Supply Duct Area Attenuation <n> PER Transformation, 0.0 Sound Control 915 1. For the absorption of. the low frequencies below .500 cycles per second the material should be at least 1 to 2 in. thick. Thin materials,, particularly when mounted on hard solid surfaces, will absorb the high frequencies and reflect the low. 2. In order to provide as much low frequency noise absorption as possible by means of flexural vibration, it is desirable to, fasten the absorptive.panels discon tinuously. This result may be attained to some extent by spot cementing, but better results are obtained when it is possible to fasten the absorptive panels to fur ring strips, leaving an air space behind. However, the exact resonance character istics 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;6 (2) adequate strength to avoid breakage; (3) fire resistance and compliance with national and local code require ments; (4) low moisture absorption; (5) freedom from attack by bacteria Table 7. Approximate Attenuation Between5 Grilles and Room 5' VOeulotlceitty FPU . 500 750 1000 ' 1250 Air Change - Mm. -. 5 10 16 20 5 10 15 20 6 10 15 20 5 10 15 20 . Livb Room1* o =db0.05 11 14 16 U 13 16 18 19 14 17 19 20 J5 18 20 21 MReodoiuuom a = 0.15 db .. 16 19. 21 22 18 21 23 24 19 22 24 25 20 23 25 26 !1 DRoeoawdd a =dba25 18 21 23 24 20 23 25 . 26 21 .24 26 28 22 25 27 28 . -- wage tiusurpuon coefficient for the room. . , f Live room-average absorption coefficient 0.05. Bare wood or concrete floor--bard plaster walls and ceiling--minimum of furniture. > c Medium room-average absorption coefficient 0.15. Carpeted floor, upholstered furniture, hard plaster walls and ceiling or bare room with acoustically treated ceiling. ^. Dead room-average absorption coefficient 0.25. Heavy carpeted floor. Walls and ceiling acoustically tiested. Upholstered furniture. and algae; (6) low surface coefficient of friction; (7) particles should not fray off at the higher design velocities; and (8) freedom from odor when either dry or wet. :. With every application, the use of sound absorptive material 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 through a duct lined with sound absorbing material, is related in a rather complicated manner to the size and shape of the duct, to the frequency of the sound, and to the sound absorbing char acteristics of the lining. Experimental evidence likewise indicates that there is no simple formula involving the variables which will apply accu rately to all cases. However, it may be stated generally that the attenua tion in decibels at a given frequency is directly proportional to the length of 916 CHAPTER 41 1954 Guide lined duct. It decreases as the cross-sectional area increases, and increases as the aspect ratio is increased. ' The noise reduction varies to a considerable extent with the frequency of the sound. In calculating noise reduction, consideration should be given both to the comparative efficiency of the duct lining material at different frequencies, and to the frequency distribution of the.noise to be quieted. In the case of fan noise, it is recommended that calculations be based upon the predominant frequency component in the fan sound level spectrum. Normally, most of the sound energy is in the region of this frequency, which generally corresponds to the blade frequency and is equal to rpm X no. of blades -f- 60. .. Where the noise reduction is calculated upon the basis of the funda- mental frequency component, the treatment indicated as required should be ample for the harmonics which are more easily absorbed than the funda mental. In quieting noise due to air turbulence and eddy currents where high frequencies predominate, the frequency 1024 should be used. Since ventilating system noise contains many frequencies, an exception should be noted to the previous statement that attenuation in decibels is directly proportional to length of duct. Most sound absorbent materials are more efficient at high frequencies than at low frequencies. In con- sequence, the attenuation in the first five or ten feet of lined duct will be greater because the high frequencies are being absorbed; Thereafter, since low frequencies will be predominant, the overall noise attenuation per foot will gradually be less. " * ' . ' . . , ^ i Duct Lining A By far the most commonly used method of obtaining sound absorption A, in ventilating systems is to line the duct with absorbing material. It is A usually more convenient to line all four sides of the duct, but a lining on one side over a longer length of the duct will, in general, give the same effect A for the same area of applied acoustical material. Subject to certain A; restrictions, the attenuation of a fully lined duet to single-frequency sounds J may be expressed by the approximate Equation 6:7 ' P R = 12.6Z, - o1-* A where R = attenuation, decibels. L = length of lined duct, feet. P = perimeter of duct, inches. A = cross-sectional area of duct, square inches, a = absorption coefficient of lining. This formula was empirically developed for a set of duct sizes ranging A--- 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 and 2048 cycles, and for absorption;.',' coefficients between 0.20 and 0.80. The duct lining material used was 1r-- in. rock wool sheet. In Table 8 are listed the absorption coefficients of a material of this type in one-half and one inch thickness. - i f *>v It is also possible to calculate the absorption by a very complicated {5/; mathematical theory.8'9 Such calculations are in substantial agreement with Equation 6. This equation may be in error when applied to other Sound Control 917 Table 8. Attenuation Data for Typical 1 in. and \ in. Thick Duct Lining Board Fbequenct cycles per second Absorption Coefficient a 1-Inch Thickness Attenuation db J-Inch Thickness. Absorption Coefficient .a o* Attenuation db 128 256 512 1024 2048 0.29 0.51 0.70 0.80 0.79 0.17 0.39 0.60 0.73 0.72 2.1 L^r A 4.9 L~ 7.6 P A 9.2 LA 9.1 A 0.13 0.25 0.40 0.72 0.78 0.06 0.15 0.28 0.63 0.71 0.8 L j A 1.9 A3.5 A p 7.9 L~ A p 8.9 L-~ A types of duct lining and to duct sizes and shapes greater than those specified. An empirically-derived chart10 representing the average experimental data on a number of different types of materials, is shown in Eig. 5. Since individual materials vary, the curves of Fig. 5 are given only as repre senting the best available averages for duct sizes of cross-sections from 6 x 6 in. to 48 x 48 in. The dotted lines are plotted from Equation 6 and show that the slope is materially different from the average values. Rectangular Cells (Plate or Cell Absorbers) If the length of duct from the main duct to the grille is shorter than the length of lining indicated by Equation 6, the duct may be subdivided into smaller ducts as shown in Fig. 6, or it can also be even more subdivided by an egg-crate construction. In such a construction in which all the sub divided ducts are the same size, sound will be equally absorbed down each channel. It is, therefore, only necessary to calculate the sound attenuation of an individual channel. For this, Equation 6 is adequate. When the number of splitter plates or cell partitions is large, the percent age free area of the gross duct size may be materially reduced; This leads to a further sound attenuation. Values of the attenuation possible, due to this cause, are given in Table 9. . Fig. 5. Sound Attenuation for Various Absorbing Duct Liners 918 CHAPTER 41 1954 Guide Sound Control 919 A. Unlined metal duct. B. Absorption lined duct (Case I). - . C. Splitter plate type absorber (Case 2). (Channels 20 in. x 3.33 in. inside). D. Cell type absorber. (Cells 5 in. x 3.33 in. inside). . .. , 1 in. thick absorption material in all eases.: <. . - - ' - Sample Calculations for Duct Treatment r; : Example 1: An air conditioning installation is to be installed in a small theater. Determine the necessary sound treatment for the air distribution system to provide a satisfactory noise level in the theater utilizing these conditions:^. . Fan tip speed 4000 fpm, total pressure 1.25 in................................... 77 db Acceptable room noise level (Table 2) ........:.................v. ..40 db 4 . Required attenuation.................... .................... .............................. -37 . db ; Solution: Natural attenuation of supply duct.. . f. Sheet metal duct 50 ft long 48 in. x 36 in. (Table 4) 50 x 0.01. .. 0.5 db Elbows, two size 48 in. x 36 in. (Table 5) 2x1....:..:..........: 2.0 db , Attenuation grilles to theater air change 10 min (Table 7) outlet velocity 1000 fpm..................... .................................. . .i......... 22.0 db ' Total natural attenuation . ..................................... . 24.5 db ' Difference between required and natural attenuation, 37 minus 24.5,. is 12.5 db. This attenuation must be supplied by sound treatment in the duet, either in the form.of duct wall lining or rectangular cells of the plate or cell absorber arrangement. \'l A similar analysis of the return duct system shows that 15 db attenuation is to be furnished by absorptive material. An inspection of the installation shows that the lining of the plenum on the suction side of the fan would prove the most eco nomical, where it would secure the dual function of heat insulation and sound ab sorption. . Example &: A 10 x 20 in. duet is connected to a private [office space in a quiet lo cation. Determine the length of lining necessary to attenuate average .fan noise satisfactorily, using a lining material of a type to which Equation 6 applies, and having an absorption coefficient of 0.40 at 256 cycles. : Assume [that: the aucfc is only 12 ft long as shown in Fig. 6, and that a 30 db reduction is required in this length. Solution: .. . Case 1. (No splitters, duct lining only). From Equation 6, ; - - 60 R = 12.6 X 12 X -- X 0.401-' = 13 db. Table 9. End Reflection of Plate or Cell Absorbers Percentage free area of absorber.............................. 50 40 30 25 Attenuation db............................................................. 1 . 2 4 5 2 covered roc* wool . . . * --' PLAN . Duct , 'branches ELEVATION Fig. 7. . Absobption Plenums With and Without Sound Cells Cose 2. (Two 1 in. splitter plates, 3 channels each 20 in. X V in.). From Equation 6, -. ; 467 !. ' / `; ' 3 = 12.6 X 12 X --~ X 0.40!1 = 29 db. 66.7 - - : -; Additional attenuation may be obtained by using additional-splitter plates or use of egg-crate arrangement,of absorbing material and application of Equation 6. 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. 7 will often prove the most economical arrangement. The absorption in the plenum may be approximated by Equation 7. T:-. . ' db (Attenuation) = 10 logit, Area Fan Discharge ! (7) The area of the plenum should be at least ten times as great as the fan discharge area. The plenum should be lined with 2 in. of muslin covered rock wool blanket, or 1 in. sound absorbing board preferably nailed to wood strips on ..the inside of the plenum. With such a lining the plenum is particularly effective in reducing low frequency fan noise. The absorp tion of the plenum in sabins is the sum of the products of each interior area of the plenum measured in square feet multiplied by its corresponding absorption coefficient. Outlet Sound Absorbers , Outlet sound absorbers are rectangular or plate cells installed directly behind an outlet or they may be the lining of a pan or plaque outlet. They are particularly effective in the elimination of high frequency whistles which are generated by air flow in the ducts. They arealso 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 correcting existing noisy installations, as the duct sections directly behind the outlets may be the only sections accessible for treatment. (See Fig. 8). . AIR SUPPLY OPENING NOISES When air is introduced into a room through a grille or register at a constant velocity, sound energy is being introduced into the enclosure at 920 CHAPTER 41 1954. Guide' crnvtd rack ed or board nnh rnT;i ; ! 'I it u ii i i, J ll f-----------,J U11 Li Li | -I ' SECTION K* Ceflabnrtwn SECTION** 9utsorten Flo. 8. Outlet Cells fob Pan Outlets ob Gbilles a constant rate.11 Due to partial reflection at the boundaries of the en closure, the intensity of sound at any point in the space builds up to some maximum value. In a large room at a point remote from the source of sound (the supply opening) the intensity can be shown to be substantially proportional to the rate at which sound energy is generated, and inversely proportional to the number of sound absorption units (sabins) in the room. It would thus appear that doubling the sound absorption of the room would halve the intensity and result in a noise level decrease of 3 db. Grille noise is similar in character to fan vortex noise. Knowing the noise level at the face of a grille for a given grille blade setting, the noise will vary as given in Equation 8 where V is the velocity of the air through the grille. db (change) = 50 logu { (8) For a change in blade setting Equation 9 applies, and in this case the' total pressure is measured directly behind the face of the grille. For a typical air conditioning grille the noise level at the grille face may be approximately 48 db with a total pressure behind the grille of 0.1 in. J,, , , , ,,,, , T(Total Pressure)," db (chaDge) " 2510610 [((TToottaal Pressure), (9) The resultant room noise level can be approximated by Equation 10. Room Level < Noise Level at Face of Grille Total Room Absorption in Sabins 10 login - (10) Total Grille Area Grille Selection - In practice the allowable total sound and the required air flow are usually known, and it is desired to determine the maximum allowable velocity. In comparing sound ratings of various grilles several factors must be known if the information is to be properly applied: 1. The threshold intensity on which the decibel ratings are based 1 2. The distance from the grille at which data were taken. 3. If stated as sound level versus velocity for a given grille, the core area (not nominal area) must be known. . 4. The sound absorbing characteristics of the test room. 5. Whether or not corrected for test room sound level; if not, the room level (with out grille noise) must be known. 6. Methods used for.recording data. (Characteristics of sound meter). Since total sound and air flow are both functions of velocity and area, the solution of the problem implies a trial and error method. It has been fiP:;% : Sound Control 92b AFio. 9. ib Flow and Sound Level Chabt found possible to present these data with sufficient practical accuracy.as a family of unifonn curves, as illustrated in Fig. 9, which are based1 on these assumptions: -- ,. 1. Threshold intensity = 10-1* watts per square centimeter:1 2. Microphone location 5 ft from lower edge of supply opening on a line,down ward at 45 deg, and in a plane bisecting the supply opening perpendicularly. 3. Where data are given as sound level versus velocity, the rating is per square foot of core area. 4. The room is assumed to have 100 sabins absorption. . 5. Plotted data are sound levels of supply openings only, correction having been made for test room level. .. ; ' \ - ' 6. Data taken with a direct reading sound-level meter with frequency weighing network intended to approximate the response of the human ear. . If the published ratings are in terms of decibels per square foot, correc tion must be made for area to secure the total sound level of supply open ings of more or less than one square foot area from Equation 11. . where Decibel Addition = 10 log,, A (11) A = core, square feet. With Fig. 9 it is possible to find directly the velocity in feet per minute which ,will give a predetermined total sound at a predetermined rate of flow expressed in cubic feet per minute. The values used are arbitrarily chosen for. the purpose of discussion, and do not necessarily represent data referring to any particular design of air supply opening. A correction chart is shown in Fig. 10 for a room having a sound absorption other than 100 sabins. . .. . Example S: Determine the core area (see Chapter 31) of an air supply grille which will maintain a noise level of not more than 40 db in a room having 100 sabins of sound absorption, if an air volume of 2400 cfm is required to maintain the proper air conditioning. Solution: Assuming a grille noise rating of at least 5 db below the noise level of the room, Fig. 9 shows that the limiting grille velocity for a total sound level of 35 db is about 725 fpm, and the core area becomes fixed at 2400 + 725 or 3.31 sq ft. If the room absorption had been greater the previously selected velocity of 725 >Pm would be safe, smce the sound level reduces. If the room absorption had been 200 sabins, a correction of plus 1.3 should be made by reference to Fig. 10, and the 922 CHAPTER 41 11954 Guide permissible velocity becomes that corresponding to a total sound level of 36.3, or approximately 800 fpm____________ _ . v . ' If the room had been highly reflective with an absorption of less than 100, the correction would be much more important. For instance, for a room of 35 saciins, a correction of minus 3 db should be made, and the maximum velocity corresponding to the 32 db total sound level would be approximately 600 fpm. . Where more than one supply opening must be considered, the problem is more complicated. If..a-similar supply, opening is added in a far corner of a highly absorbent room, the change in noise level at the 5 ft station at the first supply opening is small; however, if the room is small, or highly reverberant or both, the intensity at the 5 ft station may be almost doubled and the noise level increased nearly 3 db thereby. The simplest method of handling this problem is to treat the room as though all the air were being supplied by one supply opening. Thus, if two outlets, each supplying 1000 cfm are used, the value 2000 cfm should be used with Fig. 9. Although this method may place an unwarranted limit on velocity when used in a large room, it is seldom that such a room has a noise level low enough to justify a more complicated, though more exact procedure. In general, return grilles are selected for velocities about half the supply velocity, and when this is done, they may be neglected in sound computa tions. However, if supply and return grilles are the same size, resulting in the same face velocity, they must be treated as two supply openings. That is, if 1000 cfm are supplied and exhausted through grilles of the same area, 2000 cfm must.be used in the solution with Fig. 9. ' CROSS TRANSMISSION BETWEEN ROOMS Ducts serving more than one room permit cross talk between the rooms and should be lined with acoustical material. Where the rooms are close, together and the ducts short, the ducts should be sub-divided to provide ample acoustical treatment. Lagging .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 ventilated. Unless the ducts are lined, some of the mechanical noise from air in the equipment room may be trans mitted 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 permit a simple and practical calculating procedure to determine 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 insula tion or pipe covering does not materially increase the sound insulation value unless the material is dense, or unless it is surfaced with another sound impervious layer such as metal or board. Standard 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 SounduGontrol 923 :924 CHAPTER 41 1954'Guide of frequencies and does 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: Sound Control 925 where T = transmissibility of the support. f = frequency of the vibratory force. /n = natural frequency of the machine unit on its support (damping = 0). Equation 12 shows that the transmissibility approaches unity for disturbing frequencies considerably lower than the natural frequency of the mounting. As the disturbing frequency is increased, the transmis- ~ sibility is also increased until at the reasonant frequency, where / = /,, the. L transmissibility becomes infinite. This is not true in practice because all 1 materials have some internal damping effect. However, operating at or very close to the reasonant frequency is always serious as forces and stresses . may be multiplied 10 to 100 times. As the disturbing frequency becomes v greater than the natural frequency, the transmissibility becomes a smaller quantity, and at the value of ///,, = V2 it again has the value of unity. ^ Beyond this point true isolation is first accomplished. At a ratio of 3 to 1 ,. for / to /,, the isolation is effective enough for practical application, 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 fl results for effective vibration control, but for the lower speeds as experienced with compressor work the higher ratios become Uneconomical. A For a given installation, the speed of the compressor is fixed by the speci- ;v fications; therefore, the Value of / is fixed. That leaves only fa to be de termined, and that is accomplished by the choice of mounting material and design for the support of the machine. It is well to keep in mind that when trying to isolate vibration, no attempt should be made to isolate 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 13: J. where g = gravitational constant. : d = static deflection of supporting material. . / = frequency of the vibratory force. ' /,, = natural frequency of the machine unit on its support (damping = 0)v '. By the use of Equation 13 a set of curves may be plotted as shown in/'. Fig. 11. The first line AB, plotted as the critical frequencies for the varirj-- ous static deflections, is a curve showing the worst possible conditions or, resonant conditions. . .,v y. Plotting another curve CD, which is s/2 times curve AB, shows the*..', area MCDN in which the resifient material or mounting does more harm <T 11.Fig. Static Deflection fob Various Frequencies 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. Exam-pie 4' An electric motor driven compressor unit is to be isolated. The com pressor is partially balanced and operates at a speed of 360 rpm. The speed of the motor is 1160 rpm, and it is-belt connected to the compressor. Total weight,of the compressor 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 mini mum, and that 5 is desired. The desired natural frequency of the mounting is 360 -s- 5 = 72 cycles per minute. From Fig. 11 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 the minimum ratio of 3 the deflection would be 2.5 in. . The next step is to determine the total weight to be supported by the springs. For low speed partially balanced compressors, 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....................................................... ...!.................... 4,500 lb Concrete foundation............................................................................ ................. 9,000 lb Total..............................................:.................................................... 13,5001b 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, jt is desirable to design for at least 8 springs and one or two spares for cases of un- Knovm weights. As many as 50 springs have been used on one installation. The distribution of the springs must be balanced against the masses to be supported, otherwise the foundation design and supporting structure determine the location of the springs. . The choice of the material used in the design of the resilient mounting 's also important. For the slow-speed type compressor, a common speed found in practice is 360 rpm. For speeds below this, isolation should not he attempted except under careful supervision. Referring to Fig. 11, it is 926 CHAPTER 41 1954 Guide 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 material is the coil spring. This is also 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 designed with a working height equal to 1.0 to 1.5 times the outside diameter. A long spring of small outside. diameter has very 'low transverse rigidity, and therefore requires some`additional means of preventing side drift of the unit, and on very sensitive applications this may tend to destroy the isola tion efficiency. For speeds of 700 to 1200 rpm the required deflections range from 0.22 in. to 1.75 in.: For these conditions rubber in shear serves as a rather satisfactory material if protected from oil. For speeds higher than 1200 rpm cork specially made for vibration damping 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 possible 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 machine. If this resultant machine movement is too great for the necessary connections or the satisfaction of the customer, it can be reduced only in two ways without destroying the quality of the isolation; first, adding mass or dead weight to the machine (such as concrete) common in the application of low speed, partially balanced machinery; second, accurately balancing (both statically and dynamically) all moving parts so as to eliminate the vibration at the source. This latter method is the best engineering practice and is the modem trend. However, even with well balanced machinery, installed in the vicinity of quiet offices, it is usually necessary to isolate properly the equipment to, prevent the transmission of vibration likely to cause complaints. ' Where limitation of machine movement is desired during the starting and stopping periods, the. application of friction or hydraulic damping will.serve without seriously interfering with the efficiency of the isolation. REFERENCES ' 1 American.Standard for Noise Measurement, Z24.2-1942, American Standards Association. " * American Standard for Sound Level Meter* for Measurement of Noise and Other Sounds, Z24.3-1944, Am9eSricoaunndSItannsdualardtisonAsosfoWciaatliloann. d Floor Constructions (U. S. Department of Commerce, . National Bureau of Standards, Building Materials and Structures Report BMS17 and Supplement). ' : 4 A.S.H.V.E. Research Report No. 1205--Determining Sound Attenuation in Air Conditioning Sys tems, by D. A. Wilbur and R.,F. Simons (A.S.H.V.E. Transactions, Vol. 48, 1042, p. 267). . _# * For coefficients of commercial-sound absorbent materials see Bulletin Acoustical Materials Association, 019 No. Michigan Ave., Chicago, 111. ' . .' . # * SoundPropagation inDucts Lined with Absorbing Materials, by L. J. Sivian (Journal Acoustical Society of A1mTehreicAa,bVsoorlp. 9ti,o1n9o3f7-N38o,ispepi.n1V35e-n14ti0la).ting Ducts, by Hale J. Sabine (Journal Acoustical Society of Americ. a, Vol*. S12o,upn.d5A3.b1s9o4r0p)t.ion in Rectangular Ducts, by L. L. Beranek (Journal Acoustical Society of A. merica, Vol. 12, *ppT.h2e2T8-r3a7n,sOmcistosbioenr, o1f9S40o)u. nd Inside Pipes, by Philip M. Morse (Journal Acoustical Society of . America, V' ol1.81T1h, eppP.r2e0d5i-c2t1io0n, Oofc'Ntoobiesre, L19e3v9e) ls fr`om Mechanical Equipment, by J. S. Parkinson . (Heating and rr vents- _tlating, March. 1939, pp. 23-26). ' . .t_ n.u.. .V. XT-:. Equipment, by J. S. Parkinson (A.S.H.VJ3. Stewart'and G. F. Drake (AS.H.V.E. TbaJ- ! ''Vi":A:-KJ CHAPTER 42 '.... ELECTRIC HEATING Resistors, Heating Elements,.Elec,tric.Heating Units, Applications of Electric Heat, Types of Electric Heating Systems, Equipment and Installation Methods, Calculating Capacities, Heating Water by Electricity, Induction . , and Dielectric Heating, Power Problems........ .__ ; ELECTRICITY as a source of heat represents thermal-energyiin a re^ fined form, easily applied to space heating by a variety of-methods; and readily distributed and controlled. However, it'usually is more1 expensive on a direct-heat-equivalent basis than heat from conventional fuels, and for economical service requires careful application in the design of system; adaptation of building structure, choice of control devices, and in method of operation by the user. For special, applications and. particularly when used to supplement heating-, systems of other -types,. The compactness, simplicity*, responsiveness, accuracy, of control, safety;.and other charac teristics of electric heating may carry greater weight in ehoice of method; than operating expense or initial investment. . .a The basis of all electric heating methods and'devices, except so-called heat pumps, is in the power-toTieat'conversion constant:-! kilowatt equals 3413 Btu per hr: Because ratings'of electric heating.equipinent are ex pressed in terms of watts'input and volts at the .terminals, heating capacity calculations'are translated directly to electric power requirements without the necessity of considering ampere currents or ohm resistances. ; Definitions of Resistor, Healing Element;'Electric Hebling: UnitAnd other terms applying to heating practices will be found in Chapter 1. A'. It is strongjy recommended that compliance with the National Electrical Code and approval by Underwriters' Laboratories Inc., or other recog nized certifying agency, be required in the specifications for 'all equipment; materials, and construction-used .in electric heating systems. RESISTORS AND HEATING ELEMENTS .A - . ;- Electric resistors usually are composed of metal'alloys'siich as nickelchromium wire or ribbon, or rion-metallic compounds containing -carbon formed into rods or other shapes. Heating elements may. have resistors either in the form of exposed coils mounted on insujators or! of metallic conductors embedded in a refractory insulating material, 'encased in a , protective sheath of metal... Fins or extended surfaces may be used to add heat-dissipating area. Elements are made in many forms, such as wires, strips, rings, tubes, plates and panels. Strip elements are used for clamping to surfaces requiring heat transfer by conduction, in some types of con vection air heaters; and in low-temperature radiant heaters; Ring and plate elements are common in electric ranges and' many small air heaters: Metal or oxide conductive films on glass and ceramics have been applied, usually in the form of panels. Tubular elements may be immersed in liq uids, and when cast into metal or formed into coils, are used in water heaters, electric ranges and air heaters. . ' Cloth fabrics, woven from flexible resistor wires and'asbestos or glass 927 928 CHAPTER 42 1954 Guide fiber thread, are employed for many low-temperature purposes such as heating pads, blankets, aviators' clothing, and some radiant panel heating installations. Special incandescent lamps are used as heating elements in certain ap plications where radiant heat alone is desired. These may have tungsten or carbon filaments as resistors, and are designed to produce maximum energy in the infra-red portion of the spectrum. ELECTRIC HEATING UNITS In general, an electric heating unit is considered to be a structure con taining one or more heating elements, electric terminal connections or leads, electrical insulation, and a frame, casing or other supporting means, all assembled together into a unit. There are many varieties, designated by such characteristics as shape and size of- housing, material and arrange ment of heating elements, operating temperature of resistors, ratio of radiant to convective heat delivery, directional control for radiation, natural or forced convection air circulation, thermostatic or manual con trol, and electric load-limiting features. , So-called electric unit heaters include a 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 supple mental 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 heaters are discussed in Chapter 25. The typical wiring connection for a heater; with single-phase power supply, shown in Fig. 1, has a safety thermal trip wired in series with the magnetic contactor, thermostat, and manual switch. . ; Forced-air duct heaters have collar frames designed to fit into rec-. tangular cross-section ducts* within which are mounted closely nested resistors all wired to the terminal connections. Choice of resistor type and spacing depends on requirements for heat transfer to the air and on ob-. taining low air-flow resistance. ... APPLICATIONS OF ELECTRIC HEAT Until recently the predominating applications of electric space heating have been for convenience service, such as: (a) to supplement an existing system, locally, at times when the mail system is shut down, (b) for local, use, where the main system may be inadequate, (c) for temporary service requirements, (d) for special conditions involving separate or remote control, (e) for isolated locations, (f) where minimum initial cost is the dominant factor. Some of these requirements are readily satisfied with portable heating units. However, complete electric heating systems are now finding wide application, mainly in residences, but also in many commercial and and industrial establishments. -j. Small electric duct heaters or compact strip heaters are useful in balancing heat distribution in central fan heating systems operated with steam and hot water, and in improving temperature and humidity control for summer air conditioning. Such heaters can be installed in branch ducts or behind the air inlet grilles in each room. '' In control of heating systems, employing electric units of the forced-air duct or similar types, a basic difference between electric heating and Electric Heating 929 steam should be taken into account.. Steam is approximately a constant- temperature source of heat, at any . given-pressure, and a change in air quantity flowing over steam coils does not greatly alter the temperature of the coil surface; / The amount of steam condensed (heat input) varies in proportion to the air volume, but the surface temperature of the steam coils remains about the same. Electric heat is quite different, having a constant rate of energy input. If the air flow over electric heating elements is changed, but no change is made in the electric power input, there will be a corresponding change in temperature of the air delivered. This occurs because the electrical energy input remains constant, and the surface temperature of the heating elements will vary as is necessary to compel the air to accept all the heat. ' Thus, with electric heat the total heating effect is constant unless some compensating action is performed by controls. Automatic variation of Power supply Fig. 1. Wiring Diagram for Unit Heater the electrical heat input synchronized properly with the air flow; can be successfully accomplished by certain special methods of control. By-pass dampers as used with steam units cannot control electric heat. TYPES OF ELECTRIC HEATING SYSTEMS The principles employed in electric house heating for heat transfer and distribution, and for temperature control and cyclic operation, and the variety of equipment that has found application, outnumber those for systems utilizing fuel. This can be ascribed to the inherent adaptability of electric energy for transmission, conversion and regulation, and more importantly to the relatively high unit cost in terms of thermal equivalent as compared with fuels traditionally used for house heating; this necessi tates 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 installation 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 Standard heating units for wall mounting, of either recessed or surface type, are made with resistors of incandescent bare-wire or low-temperature $30 CHAPTER 42 ;;k: 1954 Guide (black) types and1 the1 general ^construction 'already described;)) A metal inner liner or reflector,usually) placed between: resistors; and casing, pro vides a secondary) air passage to promote circulation.and'reduce casing surface temperature at the rear. Depending on, ratio . of:. horizontal to Table 1. PrincIpal Types of Electric House. HeAtin6 Systems A. .Radiators, Convectors, Unit Heaters--Built-In and Portable : 1. Metallic resistor, high- or low-temperature . : : . - !,.12. Glass unit with metal frame ' . : . . , . ' ,: r . i : 3. Baseboard-type resistor ... .4. Resistor with fan, including unit heater . , :. . .., , . ...... 5. Resistor with focusing radiation reflector,. . . ... i 6. Steam radiator with immersion electric element J 7. Resistor unit placed in window-type air-conditioner B. Panel-Type Installations . , . 1. Ceiling panel a. Rigid composite panels containing electrically conductive rubber b. Flexible composite sheets containing embedded metallic filaments or con ductive rubber) ' c. Electric conductors embedded in plaster on lath ` 2. Wall panel ; 1 a. Rigid panels, as for ceilings : , b. Flexible sheets, as for ceilings ; 3. Floor panel a. Electric conductors embedded in concrete slab b. Soil heating cable under ceramic tile ' ' C. Central Hot-Water Systems -, . 1. .Water from electric heater pumped to radiators or convectors in rooms 2. Same, with thermal storage for ofEpeak operation - -!* 3. Fuel-fired boiler converted to electricity D. Central Warm-Air Systems .. 1. Resistance-element bank in housing or air duct 2. Fuel-fired furnace converted to electricity . * r E. Heat-Pump Systems ' ' ' ' T. Warm-air distribution through ducts, like D-l ' 2. Hot-water distribution, like C-l or 2 ! 3. Radiant panels, like B-l or 2, but with embedded tubing to act as refrigerant condenser . 4. Modification Of window-type air conditioner by addition of refrigerant reverb ing valve and controls ..; . vertical dimension, pattern of face grille, and arrangement of resistor? and deflector, the convection heat delivery constitutes between 40 and 60 percent of total output. . , . .. Ratings usually are from 1000 to 8000 watts (3400 to 27,300 Btu per hr) with some models down1 to 500 and up to 15,000 watts. Voltages are the standardized values between 110 and 240. Similar models equipped also with air circulation fans of axial type, are available; these give con vection heat delivery up to 80 percent. Other types, using the s^me components but without a fan, are arranged as floor furnaces to be installed Electric Heating 931 between floor, joists. . A manual switch and. thermostat integral with the unit are optional. . . ' ,. ., . : Portable units of the foregoing types, except floor furnaces, are ob tainable with plug-in extension cords for convenience and occasional ser vice. Ratings are.500 to 1200 watts at 110 yqlts;.special:models rated up to 5000 watts are also.made, but can be used only on branch circuits having, special wiring and receptacles.................... . ; ' .. Convector Type Unit ) ) ,, :. The location of built-in electric heating units of convector type, generally along the exterior walls beneath or alongside windows, is governed by the same principles that determine arrangement of steam and hot-wafer con vectors, with respebt tb movement of warm'arid return air. Positions on interior walls are sometimes permissible, so long as interference from opened ' doors and from furniture placement is avoided.; A' thermostat of high 1 sensitivity type and a conveniently located!.manual switch are recom mended for each unit or at least each room. '` Radiant Convector Unit ! . . Glass electric, heating units, sometimes designated, as radiant panels, depend on the heating effect produced by passage of current through a thin coating of conductive material fused to one face of a panel of J-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 coating less than 0.0001 in. thick over the entire active face of panel. Normal glass operating temperatures are 300 to 400 F, with maximum permissible temperature1 around 650 F. , ; . .-, - . Electric wiring connections are made to the panel coating at its oppo site extremities by wires soldered to the coating, by metal strips held in place with springs, or by other methods that assure low electrical resist ance. The panel is supported on insulators within a metal frame which also carries a reflector behind the glass and is arranged to provide space for air circulation. A protective guard prevents accidental contact with the hot glass. . :: Glass units have standardized ratings, usually 1000 watts, with smaller units extending down to 200 watts, for the common voltages ranging be-' tween 110 and 240 volts. Starting current for some types exceeds running current by 10 and by 50 percent.. Frame sizes vary,-from about 30 x 24 in. for 1000-watt size to 42 x 6 in. for 300-watt baseboard model; frame types are for either recessed or surface mounting.. .Thermostats integral with the frame assembly are optional. Portable units equipped with plug in extension cords are of similar construction. . Baseboard Type Unit Metal casing proportioned to resemble and replace the conventional wood baseboard along plastered or masonry walls, contains 2 or 3 resistors placed horizontally, one above another. These usually are of low-tem Perature type, with ratings 80 to 120 watts (270 to 400 Btu per hr) per linear foot of baseboard unit, at 240 volts. The maximum surface tem perature is 140 to 160 F. The vertical dimension is 6, to 8 in. above floor hue, and the projection from face of plaster about 1.5 in. Placement Within the room and method of control follow the same principles that aPply to hot-water type baseboard installations described in Chapter 23. 932 CHAPTER 42 1954 Guide Another type of baseboard unit has glass panels 6 to 8 in.'high and 30 to 42 in. long, with surface operating temperature kept below 250 F. Resistor with Focusing Reflector An example of the focusing-reflector-type heating unit is the copperbowl parabolic of circular glow heater for portable use. This has an in candescent wire-coil resistor on a conical ceramic core, screwed into a lamp- type central receptacle. Usual ratings are 600 and 1000 watts for 110 or 120 volt service. Heat emitted by radiant effect is 75 to 85 per cent of total delivery. For permanent installation,, low-temperature focusing, units are made with tubular resistors mounted within sectional trough-type reflectors resembling industrial fluorescent lighting fixtures. They may be sus pended from ceiling,or bracketed from a wall. Rated capacities are 500 to 1500 watts per linear foot of unit. Installations of this kind are mainly iri public and industrial buildings, to handle the perimeter heat loss at windows, doors or wall openings. In a modified form, such units are employed for infra-red heating and drying in industrial processes. Steam Radiator with Immersion Element ' For portable use, radiators (convectors) of light-weight 2-column con struction are equipped with an immersion element screwed into a bottom opening at one end. Usually, after charging with water and antifreeze compound the radiator is sealed. A safety valve or thermal relief plug is provided, to protect against excessive pressure in case heat dissipation is unduly curtailed by clothing, bedding or other insulating material placed' over the unit. The steam-and-water intermediate heat-transfer medium has no effect on overall thermal efficiency, but gives the unit operating characteristics adapted for certain applications. . Many recent models of window-type air conditioners are provided.with resistors, enabling them to be used also for heating service in moderate weather. Electric input for heating is usually kept the same as for cooling. Consequently, the units normally give only convenience heating and are intended for use at times when the main heating system is shut down. Ceiling Panel-Type 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 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 js 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 mouldings are furnished for wiring connections. An earlier type of construction using asbestos-board backing to form rigid panels j in. thick has been discontinued. Under normal operating conditions that cause cycling under thermo static control, the surface temperature is about 100 F. When panels are turned on in a cold room or with continuous operation, the maximum temperature reached is 120 F. The position of panels on the ceiling of a room should be as near as pos sible to exposed walls, especially at windows and doors, to counteract Electric Heating 933 cold-wall effect and to keep' the occupants never farther than 3 ft horizon tally from a heated area. The preferred location is with the terminal- block edges close to the walls and with 1-ft spaces between panels. Since it is not permissible to cut heating panels, the entire pattern for ceiling must be planned in advance both for appearance and for economy. At tachment to ceiling plaster, plaster-board or other smooth surface is made by a special adhesive applied on the ceiling along a 1^ in. fastening margin, provided around the four sides of each panel, which carries a dry adhesive tape bonded to the panel. Lighting fixtures must not be fastened or cut into the active area of a panel. Adequate thermal insulation above panels is mandatory to protect all wiring from excessive temperature and to assure economical heating service. The minimum thickness of mineral or fiber insulation (glass or rock wool, cellulose fibers, loose asbestos, etc.) is 4 in. at top story and 2 in. for inter mediate floors, whereas 6 in. and 3 in., should be the minimum correspond ing thicknesses of expanded mica insulation. A thermostat of high sensitivity type with an integral manual cut-off device should be provided in each room. To obtain economy of operation, a time switch or clock is advocated for lowering the room temperature to 55 F at night or when rooms remain unoccupied. Ceiling Panel-Type Installations with Embedded Conductors Resistors or cables for embedding in plastereid ceilings to form panel-type heating installations are electrically insulated with a special compound resistant to high temperature, water absorption, aging effects, and chemical action with plaster, cement and soil. Cable units are furnished in stand ardized lengths between 20 ft and 1000 ft, rated from 50 to 3000 watts per unit, for 120; 220 and 240 volts. They have an outside diameter about | in., the maximum safe .operating temperature is about 165 F, and the test voltage is 2500. Non-heating leads 8 ft long are attached to each unit, allowing the unit to be terminated at thermostats or in switch boxes with out causing erratic operation of thermostat by heat from cable. Units are identified in regard to rating, by label and by color code. It is not per missible to alter the length of cable or leads, nor to install, any cable unit lacking a visible identification label. For plastered ceilings, the lathing used is of gypsum or other non- metallic fire resistant type. The cable is temporarily secured to lath with strips of f-in. cotton tape spaced not over 16 in. apart. Each element is tested immediately after fastening on lath, for completeness of circuit and for insulation resistance of at least 100,000 ohms measured to adjacent plaster or structural members. The minimum spacing between cable passes or turns should be I5 in. Leads from cable to junction boxes should be placed in loom. A clearance of at least 2 in. is required from any metal lath, such lath being permissible only for reinforcement along comers at walls. Clearance is likewise neces sary at any metal objects, and this applies also to non-heating leads, as a precaution against magnetic hum. Cables must be kept away from local areas of ceiling that would be additionally heated by recessed or surfacetype lighting fixtures. All general wiring for power and light is ran above thermal insulation over the heat panel areas, or at least 4 in. above the heated ceiling surface. Plaster should be applied in three coats with the first coat trowled in the same direction as the elements. A superfine sand finish is recom mended, since a putty finish coat has a tendency to crack. While new 934 CHAPTER 42 1954 Guide 'ft plaster is drying out, the range and rate of temperature changes (either S' increase or decrease), should be kept low. Vermiculite or/other insulating S. plaster must not be used, since it causes cables to overheat. - . Thermostats should be of high sensitivity type with a manual switch and have other characteristics like those described for conductive rubber panel installations. . Electric Wall Panels Although less common than ceiling of floor panel systems, walls may / similarly be utilized for electric panel heating. However, possibility of ft damage to the electrical conductors or to their insulation, from nails driven for hanging pictures and from building alterations, as well as radiation ft, interference caused by furniture placement and interior decorations, re- ft quires consideration. Care must be exercised to assure compliance with ft any applicable codes or safety regulations. "'' . ft Electric Floor Panels -r Resistor cables of the same types which are used for ceiling panels are ft employed also for floor panel systems in concrete slabs. The. thickness ft of the concrete slab is usually made a minimum Of 3 in. when placed directly ft on soil. Precautions to be observed in.construction of floor slabs for panel ; heating are covered in Chapters 12 and 24. Cement finish If in. thick is poured and trowled above the cables. They are stapled at the specified > spacing to wood nailing strips laid on the rough concrete slab. It is ft desirable that cables be secured in place either with a to f-in. layer ftft of cement wash or thinned grout before the final if-in. cement or ter- ft razzo finish is applied, or by tacking at 2 ft intervals with daubs of cement, -f, plaster-of-Paris, strips of masking tape or other non-conductive material. % When the slab is made of light-weight insulating concrete, cables should be ft? secured by tape or cord stapled directly to the slab as in the case of plastered ftft; ceilings. With monolithic finish, nailing strips are omitted and the cable "T is strung on frames with nail spacers; frames are removed when enough ", concrete has been poured to hold the cable in place. If desired, magnesite flooring, asphalt tile or wall-to-wall carpeting may be used on the floor.. : , Spacing between adjacent turns or loops of cable, and clearance from reinforcing steel bars , or other metal bodies embedded in concrete, for.ft prevention of magnetic hum,, are the same as for plaster ceilings. Non- ` heating leads should have rigid conduit between the wall outlet box and floor. They terminate beneath the surface of the final coating! Porce- -ft lain or phenolic bushings to separate the leads should be placed with the v leads pass from raceway into the slab. Cable circuits should be tested for continuity during the time they are being laid and again while the ft top concrete layer or cement finish is being poured. ft Under ceramic tile floors, the cables are embedded in grout before tiling is laid. In the case of bathrooms, laundry rooms, basements subject .to flooding, or other locations where wet floor conditions are likely, soil -ft heating cable of lead-sheathed or other special water- and corrosion-re sistant types may be required under local regulations. Gentral Hot-Water Systems '' Heating systems of hot-water type using conventional radiator or con- ~ vector units, discussed in Chapter 22, may be operated electrically by ft; means of heat exchangers containing immersion elements (resistors) of ft- Electric Heating 935 the required capacity. Control of the resistor 'circuit by a thermostat within the exchanger is usually desirable. The water holding capacity of exchanger should be made sufficient to minimize frequency of cycling of the heavy electric load from the resistor, and for safety.- Resistors may be interlocked with the circuit of the water circulating pump,'so that they can be energized only when circulating pump is in operation under control of the room thermostat. For off-peak operation, where rate schedules for electric power make this desirable, a water heating tank of large storage capacity is employed. The system may be designed for a maximum water temperature of 250 to 275 F at pressures of 60 to 75 psig. An automatic valve is required to provide 140 to i60 F temperature at the pump, by mixing hot water from the tank outlet with cool water from the return main. Another method for heat delivery employs the flash principle, withdrawing water at high storage temperature into a low-pressure separating chamber where steam is obtained as a result of the pressure reduction; however, power for pump ing is substantially greater with- this steaimaccumulator method. In practice, tanks up to 1200 gal with immersion elements of 25 to 30 kw have been used for installations with design heat requirements up to 90,000 Btu per hr. -Thermal insulation-on the tank piping must have low heat transmission in order to cut down the daily and seasonal standby losses. Design of such off-peak systems requires careful analysis of all factors, both thermal and economic.! High investment, space required for equip ment, and other practical considerations tend to limit the application of this type of electric heating. . Central Warm-Air Systems .. - ; These systems usually employ heaters consisting of resistors mounted in a frame or housing, as mentioned under Electric Heating Units earlier in this chapter. In many cases, arrangement of the supply and return duct system can be planned advantageously to facilitate future addition of equipment for summer air conditioning; Conversion of Existing Heating Systems ; Changeover of existing conventional fuel-type house heating systems to electric operation, by substituting resistors in place of the fuel equipment in the combustion chamber of a warm-air furnace or boiler, is seldom de sirable. Excessive thermal losses from such central equipment and lack of adequate refinements in the distribution facilities and controls, ' will usually cause high operating cost. However, where heat delivery into the system is accomplished by a steam or hot-water coil assembly located within a duct system, replacement or supplementing with a bank of resistors like those employed in electric unit heaters is sometimes advantageous. A case of this kind occurs where standby heating is needed to maintain safe or comfortable temperature in isolated rooms, during emergency conditions or when the normal electric service for lighting and motors is not in use. Heat Pump Systems Where summer air conditioning is wanted in addition to heating, the heat-pump type of all-year system, which utilizes a refrigeration com pressor unit in conjunction with a central-plant installation, is finding a number of applications. It reduces electric input demand and consumption for heating to about one-half or one-third that with the resistance method, the reduction depending mainly on temperature level of the heat source ,936 CHAPTER 42 1954 Guide used and on the type of heat distribution system and its controls. In general, the conditions most favorable to heat pumps occur Where, due to climate or operating requirements, the compressor capacities needed both for heating and for cooling service are the same, or nearly so. -Customary methods of conveying the heat output from heat pumps to the space served are indicated in Table 1. The main types of heat pumps and the characteristics of heat sources utilized are discussed in Chapter 37. Some recent models of window-type air conditioners are being equipped for operation as heat pumps. They have refrigerant reversing valves and controls, provided either at the factory or optionally by the installing contractor. Such units are intended for between-season or convenience heating only, since they do not give good performance when the outdoor temperature, falls below 35 to 40 F, and they lack means for defrosting the evaporator coil. In the case of heat pumps using air as heat source, it is shown theoretically and found in practice that heat delivery capacity falls off rapidly as out door temperature decreases, whereas the heat requirement increases di rectly with indoor-outdoor temperature difference. Deficiency at tem peratures below the balance point can be made up by supplementary electric resistance elements, but this adds disproportionately to power demand. Moreover, seasonal energy consumption by such resistance heating, per kilowatt of demand established, is much less than for the heat-pump cycle itself, and the combination gives load characteristics unfavorable to the utility company for rendering low-cost electric service. An alter native 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 two to three times that of resistance types. However, in practically all cases the summer air-conditioning service obtained with conventional heat pumps is as valuable to the user as the winter heating. Resistance heating systems, except the minority using mechanical air circulation through ducts, do not lend themselves to consolidation with summer air conditioning features, and consequently, an independent cooling installation is necessary. Heat pumps thus have, an advantage over such dual systems. CALCULATING CAPACITIES The procedure outlined in Chapter 12 for calculating the heating load should be used for electric systems. Load expressed in Btu per hour is converted to kilowatts by the divisor 3413 Btu per kilowatt. All the . energy applied to a resistor transforms itself into heat, unaffected by tem peratures of the surrounding air and of surfaces receiving radiated heat. However, both electric power input and heat output are directly affected by voltage at the resistor 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. Selection of proper indoor and outdoor temperatures for design of electric heating systems is more critical than for those using fuel, since in case the installed heating capacity is found deficient, the only recourse is to add more electric heating units or to bring the supply voltage up to the permis sible maximum. On the other hand, fuel-operated systems ordinarily Electric Heating 937 permit raising the rate of combustion somewhat above the nominal rating, although there may be some penalty on efficiency, operating or maintenance expense, or overall performance. Indoor temperatures usually specified are shown in Table 2 of Chapter 12, subject to the indicated notation concerning effect of radiant or panel heating. Moreover, allowance is required for radiation effect of cold surfaces if there are large windows, and for the continuing trend toward adoption of higher indoor temperatures. Concerning outdoor temperature for design, attention is directed in the case of electric heating systems to the cautionary remarks relating to winter climatic conditions in Table 1 of Chapter 12. Judgment must be exercised in choice between values In Common Use and TAG 97.5 Percent Basis, which show differences as large; as 15 deg for some cities. If indoor temperature is taken at 70 F, it may be inadvisable to select outdoor temperature as high as the TAC 97.5 percent value. The arbitrary addition of a percentage safety margin on the calculating heating load or on the specified rated capacity of heating units to be in stalled, is not recommended, especially in case the outdoor temperature for design is taken at or near the In Common Use value instead of TAC 97.5 Percent Basis.__ Such practice increases the peak electric demand and usually the cost of electric service. It also tends to produce excessive onand-off cycling, impaired temperature regulation, and needless voltage variation or flicker disturbances with bad effect on lighting and other electric devices. Many electric heating systems are of decentralized type, with a thermo stat provided on each convector or for each room as recommended by manu facturers of such heating equipment. This practice compensates for varia bility of heat contributed by auxiliary sources such as sunshine, lighting and appliances. It also gives opportunity for diversity of power demand, i.e., the non-coincidence of electric load from all the convectors, panels or heating units of an installation. Manual switches are also commonly provided in such decentralized installations to permit cutting off heat or reducing temperature in rooms when not occupied. Such decentralized operation, advocated as an economic measure with electric heating, re quires that consideration be given to adequate capacity for warm-up, as against the uniform-temperature operation with a fully centralized system. It is essential that buildings intended to be heated electrically should be well constructed, with adequate thermal insulation having impervious vapor barriers, and with storm windows or double-glazed window units and weather stripping to minimize heat loss and air infiltration. Open fire places should be eliminated wherever possible, because they induce ex cessive infiltration. The relatively high electric cost for thermal energy, about $6.00 per million Btu at $0.02 per kwh, for example, as compared with about $1.20 for oil at $0.12 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 seasonal energy consumption in kilowatt hours, divided by degree-days and by volume of gross heated ?Pace expressed in thousands of cubic feet) between 0.2 and 0.3. The features necessary to hold consumption within these limits result in con struction that for 5000 degree-day climate with 0 F outside design tem perature, gives a calculated heating load of 4000 to 5000 Btu per hr per 1000 cu ft gross volume. Heat factors up to 0.4 are not uncommon, but 938 CHAPTER 42 ' 1954 Guide experience shows that such high heat, requirement may result in excessive operating cost. : ., ii HEATING WATER BY ELECTRICITY Electric water heaters for hot-water service in residences and commercial buildings are predominantly of the automatic storage type. These gener ally have a cylindrical tank mounted vertically, With a primary electric heating element or resistor near the bottom and a secondary unit located' within the upper one-quarter of the tank. Water heaters of single-heatingunit 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. - Instantaneous heaters are used in special cases only, because 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 par tially standardized within the electrical industry, 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 secondary unit and 20 watts for 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 capaci ties shown in ASA Standard C72.1-1949 is reproduced in Table 2. The wattages listed in Table 2 are minimum recommended values for con tinuous service. Some departure from the standardized watts-per-gallon ratios is to be expected, as experience indicates that increased hot-water use with automatic 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. Thermo stats 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: 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, thermostats 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 re- Electric Heating 939 sistor in which electrodes are immersed. `Close temperature regulation and compensation for the effect of variable amount and composition of solids and gases in the water are difficult to obtain with small unattended heaters of this kind. The electrode type of construction 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 obtainable at cost low enough to make it competitive with fuel-fired boilers for steam pro duction. .: Tanks of electric heaters are regularly constructed to withstand a 300 psig hydrostatic test pressure and are rated for a safe wprking 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 rnay be desirable also to provide sam/5ctaZ mefaZ anodes , of magnesium, 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 Table 2. Standard Rated Capacities op Electric Water Heaters Tank Size Gallons Nominal 30 40 52 66 80 110 120 140 Range 30 to 35 35 to 45 45 to 55 55 to 70 70 to 60 90 to 115 115 to 135 135 to 175 ' ' Rated Input, Watts : Two-Unit Heater Primary .. ' ' Secondary 600 ,750 1000 1250 1500 . . 1000 1250 1500 2000 . 2500 2000 2500 3000 3000 4000 4000 Single-Unit Heater 1500 2000 2500 3000 4000 outlet, if not provided by manufacturer within or outside the tank shell and inside the insulated jacket,, may be placed in the external 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 conditions. ;; Occasionally, an uninsulated tempering tank is installed ahead of an TMe water heater, enabling the cold inlet water to. absorb heat from the basement or room air---if conditions are such that objectionable sweat ing does not occur. The practice of connecting a tempering tank with a co^> electric heater then furnishing 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 percent minimum, which allows 10 percent for thermal loss through the jacket insulation. In service, the quantity of water withdrawn from an automatic storage heater has con siderable influence on overall efficiency. With increasing quantities, ser- yice 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, ef- ciency approaches zero since no useful work is done. Hence oversizing *940 CHAPTER 42 - 1954 Guide || a water heater by having too lai-ge a tank impairs the service efficiency. ` Excessive: heating-unit wattage, causes undesirably high electric demand. Undersizing of heaters obviously results in inadequate and unsatisfactory T hot-water service. ; Selection of electric heater capacity for residences is made by reference to rating tables which take into account the number of occupants, number of ; bathrooms or plumbing fixtures, and presence of appliances such as laundry equipment, dishwashers, and the like. Information of this kind is in Chapter 49 and in design manuals issued by the electric utility industry and: by heater manufacturers. For commercial, applications, the hourly hot-water, requirements must be analyzed and the best, combination of tank capacity and heating element rating determined, with due considera tion 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 so-called Fig. 2. Domestic Hot-Water Heater for Off-Peak Service off-peak service under which the charge for energy consumed during, desig-, nated hours is lower than for normal or unrestricted 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!. customer in excess of the demand resulting from the customer's other uses of electricity, or (b) keep the water heating load off the electric utility system during peak hours. In general, Case (a) occurs where rate schedule contain a demand charge component, and Case (b) where a special low rate applies to off-peak consumption. Water heater circuits are controllw with relays actuated by an electric-clock mechanism or by a carrier-current impulse impressed at suitable intervals on the electric distribution system,^; or by an automatic load-limiting type of control. '' " One arrangement of domestic hot-water heater for off-peak service, shown - in Fig! 2, has the lower heating unit under control of an off-peak switch. Upper unit is connected directly to the line, so that in case the reserve of hot water becomes depleted, the top thermostat brings its heating unit into operation only until the upper portion (usually about 25 percent) . of tank contents reaches the thermostat temperature. Water heaters employing the heat-pump principle are now in bmit$J.;.Ta trial use, obtaining annual performance factor (sometimes called coefficient-^ Electric Heating 941- of performance) approaching 2.5. This value represents the ratio of useful heat delivered, to the direct heat equivalent of total electric input. The predominant models have tank capacity of approximately 55.gal, hemietic type compressors rated' i or J hp, and small circulating fans. So-called vagrant heat occurring within the basement or utility room is generally the heat source. In some cases there is secondary benefit from dehumidifying, and an appreciable cooling effect is produced. Present limitations include high initial cost, low recovery rate, restricted maximum temperature, and necessity of condensate drain connections, compared with conventional electric resistance-type and fuel-fired water heaters. INDUCTION AND DIELECTRIC HEATING These methods, employed for industrial processes requiring extreme speed or close control of heat location, "do not lend themselves to space or water heating. However, since they are sometimes proposed for con sideration, the operating principles are described briefly. Any electrically conducting material placed in an alternating magnetic field develops eddy currents that generate heat. The rate of internal heating is so high that conduction away from the zone to be treated does not unduly lower tlfe temperature. The field is created by ceils connected to an alternating-current power source such as motor-generator set, a mercury arc, or an electronic-tube or spark-discharge oscillator, producing frequencies usually between 250 and 10,000 cycles per second, but for some applications up to 500,000 cps. The coils are generally copper tubes through which cooling water is circulated. Induction heating apparatus must be specifically designed for each application such as melting metals, brazing, heat treating internally or in zones, and surface hardening without oxide scale formation or distortion. Dielectric heating, for materials that are non-conductors of electricity and are poor thermal conductors, requires a high-frequency electrostatic field produced at high voltage and very high frequencies reaching 50 mil lion cps. The method is well adapted to continuous-flow production process including manufacture of bonded plywood, drying of deep-pile fabrics, dehydration of granular or crystalline materials, and sterilization of foods. POWER PROBLEMS Rates 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 ex penses 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 instantaneously 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's use of his premises. Most of the heating loads in a region occur simul taneously, thereby tending to create peaks for which the capacity of the dectric system must be adequate. Accordingly, rates contain in one way I !' M . 1 '!.* 942 CHAPTER 42 1954 Guide or another, charges both for demand and energy. Dempid may be in dicated 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 capacity 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 consumption. Decentralized con trol 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 switching whereby electric service to individual rooms or circuits is shifted in rotation by an automatic timing device and sequence is modified by out door 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 ap pliances, refrigerator and water heater, cooking range, and the space heating system. When the demand exceeds a preset value, one or more heating circuits are cut off progressively in rooms least affected by the inter ruption. 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 light ing, appliances and cooking ranges is contributing some useful heat at such times. Another form of limiting control for 120/240-volt 3-wire circuits pro vides 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 or 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 desired, a clock-operated master thermo stat can be provided to lower the heating-system voltage. On some' electric utility systems, centralized control by means of a pilot-wire or carrier-current actuating a relay is applied to house-heating installations. 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 especially for types of resistor units that have a power input, when cold, as much as 50 percent above the rated value abnormal operating temperature. Operating Costs The range of electric costs for house heating, on residential rate schedules typical of country-wide conditions, is from something over two cents per kilowatt-hour where house-heating consumption comes mainly on the Electric Heating bottom step of a block-type residential rate, to.as little as half that figure in areas served by large hydroelectric systems. Since the range of heat factors for houses of differing construction types with various methods of resistance electric, heating and with a variety of occupancy is likewise more than 2-to-l, costs of house heating for dwellings of the same size in similar winter climates may vary through a range of nearly 5-to-l. However, an Table 3. Relation op Resistob Voltage to Heat Deliveby Condition' 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 Minimumr: rr- Maximum.. .. Tolerable zone ' Minimum........ Maximum. . Emergency conditions. Volts 120/240 118/236 Heat Delivered % ouuu-eu ii nouse can be heated with 8000 kilowatt-hours of electrical energy annually in 5000 degree-day climate, if a heat factor of 0.2 is attained by means of good construction and adequate insulation. Voltage Requirements The preferred nominal system voltage at point of electric utilization by equipment, for single-phase 3-wire systems necessary with space heating, is 120/240 volts, as stipulated by standards of the electrical industry (EEI 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. However, naturally variations exist from time to time in the conditions 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, ex pressed in percent of rated delivery with the normal 118/236 volts (at terminals) is given in Table 3. Voltages stipulated for secondary distribution systems are at point of service entrance to the building; the drop of voltage in the house supply wiring to terminals of the heating equipment may be 2 to 3 percent, thus re ducing heat delivery by some 5 to 8 percentage points below the favorable zone and tolerable zone values included in the last column of Table 3. Ac- 944 CHAPTER 42 1954 Guide cordingly, 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 capacity and voltage for equipment, wiring and controls. BIBLIOGRAPHY Electric House Heating--Load Characteristics and Economics, by W. F. Friend {Proceedings of Midwest Power Conference, April 1951). Electric House Heating, by E. E. Parks (Electrical Engineering, August 1951). , Electric House Heating, issued by Rural Electrification Administration (REA Bulletin 142-1. November 1952). '. Complete Electric House Heating, by F. A. Compton {Edison Electric Institute Bulletin, May 1950). Experience with Electric Space Heating, by R. H. Giedd (AIEE Conference Paper, January 1953). House Heating Experience, by C. E. Simpson (Electrical World, October 9, 1948). Heating by Electricity in Tennessee Valley Area, by B. H. Martin and T. W. Newberry {Heating and Ventilating, May 1948). Longview House Heating Data, by H. G. Kelsey {Electrical West, September 1945). .Electric Storage Heating Serves New Oregon School, by W. Bruce Morrison, {Heating, Piping and Air Conditioning, June 1949). - Electric Space Heating and Resulting System Load Factors, by T. H. Allen and C. D. Anderson, Jr. {AIEE Conference Paper, January 1953.) ' Electric House Heating Load Characteristics, by R- E. Sinclair {Electrical West, September 1950). House Heating Load Characteristics as They Affect Wiring Costs, by J. B. Cochran {Electrical World, April 12, 1947). Heat Factor Formula to Calculate Electric House Heating, by H. C. Bender (Electrical World, May 12, 1945). . Modulating and Load-Limiting Controls for Electric House Heating, by W. F. Friend {Proceedings of American Power Conference, March 1953, also Heating and Ventilating August 1953, p. 82). ' Progress Report on the Heat Pump, by W. F. Friend {Refrigerating Engineering, January 1951). Methods Developed for Built-In Radiant Heat {Electrical West, December 1948). Performance of Electrical System of Panel Heating with Four Stages of Insulation, by R. J. Lorenzi and J. F. Schreiber {Heating, Piping and Air Conditioning, January 1949). Radiant Heating by Electricity, by L. N. Roberson {Heating and Ventilating, September 1946, p. 89). Low-Voltage High-Current Radiant Heat, by R. S. Tice {Electrical West, December 1947). . Applications of Radiant Energy {Lighting Handbook, Illuminating Engineering Society, 1952, Section 18). Radiant Glass Heating Panels {Technical News Bulletin, National Bureau of Standards, May 1953). Radiant Glass Heating Panels by P. R. Achenbach (Heating and Ventilating, January 1953, p. 83). American Standard--Household Automatic Electric Storage-Type Water Heaters, ASA C72.1-1949 (Na tional Electrical Manufacturers Association Publication No. WHl-1949). Federal Specification for Domestic Electric Storage Water Heaters, W-H-196, amended May 1949. Application of Electric Water Heaters to Domestic Service, by C. G. Hillier (Heating, Piping and Air Conditioning, November 1946). Industrial Electric Resistance Heating, by Lee P. Hynes (American Institute of Electrical Engineers, Paper No. 48-247). . Induction and Dielectric Heating, by Kennard Pinder (Electrical Engineering, February 1947). EEl-NEMA Preferred Voltage Ratings for A-C Systems and Equipment (Edison Electric Institute Publica tion No. R-6, May 1949, also Notional Electrical Manufacturers Association Publication No. 11, May 1949). Standard Handbook for Electrical Engineers (McGraw-Hill Book Co., 1952). , CHAPTER 43 CORROSION AND WATER FORMED DEPOSITS, CAUSES AND PREVENTION Definitions, Classification and Characteristics of Water, Causes and Prevention of i Scales and Sludges, CauseB and Prevention of Slimes, Under-Water Corrosion, Atmospheric Corrosion, Buried.Pipe Lines, Handling Water Treating Chemicals, Legal Regulations THE surfaces of heating and ventilating equipment that are in in timate contact with water sometimes are affected by the chemical characteristics of contacting waters to such an extent that prohibitive amounts of insoluble materials are formed or corrosion ensues at an in sufferable rate. To avoid or to correct such troubles, it is desirable that heating and ventilating engineers have a general appreciation of industrial water chemistry. The principal purpose of this chapter is to provide those criteria by which the average engineer may judge whether a problem is one that will yield to rather simple remedies, or will require the skill of an experienced water technologist. : DEFINITIONS The following definitions for water-formed deposits, corrosion, and closely allied terms have been proposed: , 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, sludge, corrosion products, or biological deposits. Scale. Scale1 is a deposit formed from solution directly in place upon a confining surface. It is a deposit which will retain its physical shape when mechanical means are UBed to remove it from the surface on which it is deposited. Scale, which may or may not adhere to the underlying surface, is usually crystalline and dense, fre quently laminated, and occasionally columnar in structure. . Sludge. Sludge1 is a water-formed sedimentary deposit. It usually does not cohere sufficiently to retain its physical shape 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. Biological Deposits. Biological deposits1 are water-formed deposits of biological organisms or the products of their life processes. Biological deposits may be mi croscopic in nature, such as slimes, or macroscopic, such, as barnacles or mussels, hlimes are usually composed of deposits of a gelatinous or filamentous nature. Corrosion. Corrosion* is destruction of a metal by chemical or electrochemical reaction with its environment. In the corrosion process, the reaction products 'orrueii may be soluble or insoluble in the contacting environment. Insoluble cor rosion products may deposit at or near the attacked area, or be carried along and deposited at a considerable distance from the attacked area. Corrosivity. Corrosivity* is the capacity of an environment to bring about de struction of a metal by the process of corrosion. Corrosivity is a property of the environment, but it has no significance until the metal in question is specified. 945 946 CHAPTER 43 1954 Guide CLASSIFICATION AND CHARACTERISTICS OF WATER For industrial use there is no accepted conventional classification of water. Rather, each industry usually develops a body of ideas applicable to its own water problems.4 . For heating and ventilating engineers, it is perhaps most convenient to distinguish between mineralized waters and condensates. ' ' O Mineralized Waters ' .. All the waters found in, streams, wells, lakes, and the ocean are min eralized. 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 Table 1; Mineral Analyses Typifying Composition of Waters Available USAand Used Industrially in the Substance Location ob ABEAa'b -Unit ; a) (2) (31 -(4) (5) (6) (7) (8) (9) SiO* Fe Ca Ms Na K 12 37 10 22 14 0 6 0 0 1. 0 0 5 36 62 92 .98 02 3 155 ' '466 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 HCO* 14 13 119 202 339 334 549 210 150 SO 10 ' 2 22 135 84 121 11 389 2,700 Cl 2 10 13 13 10 280 22 117 19,000 NO) 1 0 2 13 0 1 3 31 66 165 426 434 983 564 948 35,000 12 11 98 165 287 274 8 172 125 Non-Carbonate Hardness..................... CaSO 5 7 18 40 58 54 0 295 5,900 * All values are parts per million of the unit cited to nearest whole number (see Reference 5). b Numbers indicate location or area as follows: (1) Catskill supply--New York City (2) Swamp Water (Colored) Black Creek, Middleburg, Florida (3) Niagara River (Filtered) Niagara Falls, New York . (4) Missouri River (Untreated) Average - (5) Well Waters*--Public Supply--Dayton, Ohio--30-60 ft. (6) Well Water--Maywood, Illinois-- 2090 ft. (7) Well Water--Smithfield, Va.--330 ft (5) Well Water--Rosewell, N. Mexico , ( 9). Ocean Water--Average are more likely to be contaminated with municipal sewage and trade', wastes. Virtually all mineralized waters also contain biological organisms.' Mineralogical Characteristics. The character and amount of extraneous' inorganic materials--including deleterious gases--dissolved and sus pended therein, describe the mineralogical characteristics of any water. Revealing such information 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.5 . All values recorded are in terms of parts per million.* This is the approved standard terminology for reporting the results of mineral analyses.6 Values reported in the other terms commonly used may be. converted into the standard form by using the factors listed in Table 2. 1 'Porta per million ore hereinofter abbreviated ppm. A port per million signifies o unit weight of mote- rial per million unit weights of the solution. . ,. Corrosion and Water Formed Deposits, Causes and Prevention 947 Table 2. Conversion Factors for Water Analyses To Convert Grains per U.-S. gallon ... . . Grains per Imperial gallon Grams per liters................................... Mg per liter. ................... ` . Into ppm ppm ppm Multiply by 17 14Ji 1000 1 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 8, depending upon their free COj contents. Polluted waters, which include those derived from wells or swamps 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 syn thesize 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 di visions 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 bacterio logical tests, must be made. Tests upon the water itself are seldom satis factory, and true indications of the sliming characteristics of a water can only be determined by the analysis of deposits on surfaces having a temperature close to the temperature of the final design equipment. The Phtla Algae Fungi Table 3. Principal Slime Formers Rough Division op Phtla Single celled, sometimes forming slimy sheets. Many celled in either sheets or fronds. Bacteria (Schizomycetes) 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, occasion* ally form slimy aggregates. The alga-like fungi (Phycornycetes) and the stalked fungi (Basidomycetes) rarely form slimes but their filaments may hold together the slimes of other organisms. '948 CHAPTER 43 1954 Guide Table 4. Plant Wateb Supplied Examination WATER SUPPLY-- 200 feet deep well--average water temperature i>3 Jb~ water is producing a brown stain in plumbing fixtures. SAMPLE-- The sample was scraped from the surface of the shell and tube condenser of #2 Freon Compressor on the meat chilling room. The sterile sample bottle was filled one-half with deposit and the balance with circulating water. No preservative was added--pH at time of col lection was 7.4. BACTERIOLOGICAL LJ ORGANIC CONTENT |v| PROBLEM-- : A 26-ton Freon--12 Compressor has head pressure about 10 lb higher than during initial operation, without . change in water temperature. Deposits have been observed on heat exchanger surfaces. It is desired to know the nature of these deposits and if they are the cause of this increased head pressure. MACROSCOPIC EXAMINATION-- MICROSCOPIC EXAMINATION-- Heavy brown flocculant material settles rapidly in clear water. pH--7.3 Odor--woody, mouldy. Inorganic Material--small amount white crystals. Amorphous Material--small amount brown. Iron Bacteria--profuse growth of crenothnx--(Photo usually included). CULTURAL NATION-- EXAMI Sabouraud's Agar . ., 1. Aerobic gram positive spore-forming rod with mucoia sheaths. (Photo usually included). 2. Short gram negative coccibacilli (Photo usually in cluded). TOTAL COUNT . 100,000 organism/cc. DISCUSSION-- RECOM MENDATIONS-- The presence of common slime-forming organisms in the deposit combined with high organic content indi cates that the deposit is bacterial in origin. Heat transfer reductions would be caused by such a deposit. These deposits, combined with crenothrix, can cause corrosion of both ferrous and non-ferrous metals. It is recommended that the water be treated at the sue tion side of the deep well pump with chlorine in quanti ties sufficient to maintain a free chlorine residual o 1.0 ppm at the discharge of the shell and tube cle7; This treatment can be scheduled on an intermittent basis. __ results of such a test are commonly reported in the manner illustrated in Table 4. Condensates - All condensates' result from the chilling of water vapor. Such chilling may result from natural causes, thus producing dews, sweats, rain, and snow, or from artificial causes, as in steam condensing equipment, pro ducing condensate or r" eturn...w...a..ter. " ' 1 11 1 ' 1---:--l of Corrosion and Water Formed Deposits, Causes and Prevention 949 as cooling water in recirculating systems. The deleterious gas contents of condensates, however, very often create serious corrosion troubles: The data in Table 5 typify the chemical composition of the atmosphere in rural and metropolitan areas, and of stack gases 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 pound per square inch absolute. .: The most common deleterious gases entrained by steam are oxygen and carbon dioxide. In rare instances, hydrogen sulphide, sulphur dioxide, or ammonia are present. In most steam condensing equipment,7 - 8 the non-condensable gases entrained with steam accumulate so that the amount present in the vapor space is several hundred times higher - than in the incoming steam and Table 5.; Data Typifying the Deleterious Gas' Content op ' Different Atmospheres : Aib ' . 1 1 : ; ' Flue Gases Name of Gas Chemical Formula : Bubal ` % by Vol ume. Partial Pres* sure psia Metro politan Partial % by Pres Vol sure ume . psia 1mm. Coal Fuel Oils %by Vol ume Partial Pre^ % by sure -. Vol ume psia. Partial Pres sure psia Natural Gas % by Vol ume Partial Pres sure psia Oxygen........................ Carbon Dioxide........ Sulphur Dioxide___ 0*. CO* SO* 21 3.143 : 21 3.143 : 2 * 0.299 0.03 0.004 0.08 '0.009 15 7 2.245 None None' 0.003 0.004 0.07 0.010 7 1.048 10 1.497 13 1.946 10 . 1.497 0.03 0.004 0.0001 0.0015 the amount dissolved 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 sulphate decrease with the rising temperature within a moderate range of temperatures. Surfaces transferring heat into water, such as condensers and 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 950 . CHAPTER 43 1954 Guide insoluble carbonates (or, in the case of iron in the presence; of oxygen, ferric hydroxide or oxide may be formed). 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 apparent solubility of calcium carbonate at decreasing pH values (in creasing concentration of hydrogen ion) shown in Fig. 2, the carbonate really going into -solution largely as bicarbonate. It is sometimes desired to evaluate the tendency in a particular water toward the separation of calcium carbonate, which may be desirable as a Corrosion and Water Formed Deposits, .Causes and Prevention 951 b. The water may be treated within the equipment to promote the separation of dissolved solids as sludges, rather than as scale which is;-in most cases; more'ob jectionable. . 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. . , : ... . . i , d. Substances, such as the polyphosphates, having the property of inhibiting the precipitation of calcium carbonate from solutions supersaturated with it, may be e. The pH of the water may be lowered (hydrogen ion concentration 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 must be: made for each; type of equip ment, and will be affected by local considerations. Fig. 1.- Solubility of Gases at Partial Pressure of 1 Psi means of establishing a corrosion-resistant film on metal, surfaces, or in other circumstances may be undesirable because of the impedance of the: calcium carbonate film to heat transfer. This tendency is indicated approximately by the Langelier Index,9 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,'mag nesium, and iron, which form relatively insoluble compounds. In the various soften- , ing processes this removal of these elements is accompanied by the addition of otn . elements, particularly sodium, the compounds of which are relatively soluble. Fig. 2. Solubility of Calcium Carbonate in.Distilled Water Containing Carbon Dioxide (pH Values at Approximately 7S F) . 4 JoiiraoiidaPte<1 ,TOm (1> In<i' 4 En- chem, 20 (1928) 1107--by Baylis. . (2) J.A.CS. SO (1920) 2086--Frear Once-Through Equipment and Closed Recirculating Systems Where abundant supplies of water are available at low cost, the cooling water may pass through the equipment once, undergoing a slight, rise in temperature. Little difficulty from scale should be experienced in this case unless the carbonate hardness is more than 200 ppm, or the water has been treated to induce incipient calcium carbonate precipitation. Closed recirculating systems in which the water is cooled indirectly, as in radia tors, and returned to the equipment, should usually be subject to li'ttle rouble with scale. However, in both once-through and closed recirculatlng systems, slimes may cause trouble. ,, ^ there is some tendency for scaling, it may usually be prevented by he addition of small amounts, about 5 ppm or less, of polyphosphate.10 Alternately, a minor lowering of pH by the addition of carbon dioxide or sulphuric acid may be effective if permissible from corrosion standpoint. 952 CHAPTER 43 1954 Guide 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 concentration of solids because of the evaporation of some of the water into the cooling air, and, moreover, the aeration removes carbon dioxide: Both factors promote the tendency to deposit scale. If the conditions are particularly adverse, it may be necessary to subject the water to a softening treatment before use, this being the more feasible because of the reduced water requirement in such a recirculating system. When this is not practicable, or when the tendency to scale formation is only moderate, a considerable improvement may be effected by the Fig. 3. Solubility of Calcium Sulfate and of Calcium Carbonate fob Comparison (CaCOi in Equilibrium with Normal COt Content of the Atmosphere) - Fig.-S Adapted from Bull. No. 16, Univ. of Mich. "Formation and Propertiee of Boiler Scales" by P. E Partridge. addition to the water of organic compounds such as gelatine, glucosates, dextrine, and tannin which tend to prevent precipitated material from forming adherent scales. In systems of this kind, the loss of liquid as spray from the cooling towers or spray ponds may limit adequately the final concentration of solids in the cooling water. If not, provision must be made for sufficient purging of used water. , Heating Systems In hot water heating systems or in steam heating boilers where all con densate is returned, troubles from scaling should not be severe. If necessary, sodium phosphate or sodium carbonate may be added to the water to prevent the formation of adherent calcium sulphate scale. , Boilers and High Temperature Equipment Where temperature exceeds 250 F, complete softening of the water is the only nractical method for minimizing sludge formation. This is Corrosion and Water Formed Deposits, Causes and Prevention 953 usually accomplished by artificial or natural zeolites (called also ion-ex change materials) or by hot-process precipitation softeners. In boilers operating at pressures above 100 psi virtually all the calcium, magnesium, silica, iron, and manganese salts entering with the feed water are potential scale or sludge formers. In low pressure boilers (100-250 psig),' the formation of adherent cal cium sulphate (anhydrite) scales is most to be feared. Such deposits form on the hottest evaporative surfaces. It is a material of low heat con ductivity. Even a layer of egg shell thickness may so impede the rate of heat transfer as to bring about over-heating of the metal. The ortho-phosphates of sodium are most frequently used to prevent sulphate 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 sulphate. To a lesser extent, sodium carbonate (called also soda ash and sal soda) is also used. Most of the effective boiler compounds contain either phosphates or soda ash, or both. Certain organic materials and colloids are some times found to minimize scale formation. Where chemicals are introduced directly into the -boiler, in amounts adequate to prevent scale, sludge is formed in amounts proportionate to the calcium and magnesium salts entering with the feed water. To prevent troublesome accumulation of this sludge, as well as soluble salts, as evaporation occurs, some blowdown of boiler water is necessary. CAUSES AND PREVENTION OF SLIMES A water containing slime-producing organisms will produce 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 quantities 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 heat transfer, surfaces. Other organisms capable of causing similar difficulties use such a wide variety of food material as algae,11 iron compounds,1' and inorganic sulphates.1' At present, the use of toxic chemicals and irradiation are the two general means employed in slime 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-organisms such as barnacles and nussels, but these paints must be renewed at frequent intervals, and are not applicable 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 the more common chemicals used in slime control are shown in Table 6. Chlorine is the only chemical to which is attributed the ability to de- . stroy slime-forming organisms. The others are presumed to poison marine organisms, most of which recover when the chemical is not used regularly. Corrosion and Water Formed Deposits^ Causes and Prevention 955' While chlorine is the most generally used chemical, tbeiuse of others mayoccasionally 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 cause1 blocking of the 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-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 sulphate may be used for the removal of slime already formed. . For this purpose, chlorine gas is used. After being cleaned, the other chemicals may be used to prevent the reestablish- TableS,. Common Chemicals .Used fob Slime Control Chemical Trade Name Physical State* Chlorine Hypochlorites : Chlorinated Phenols Sodium--- Potassium Permanganate .. Copper Sulphate Chlorine Calcium Hypochlorites Sodium Hypochlorites , Chlorophenylphenate v Tetracnloropnenate, ` . . Pentachlorophenate Permanganate of Potash Blue Vitriol Gas Crystalline Briquettes Briquettes Briquettes Crystalline . Crystalline *As Shipped. ment 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 materially reduce heat transfer efficiency, will often be unaffected by treatment which completely eliminates algae. Closed Once-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 hypochlorite solutions, fed intermittently, are used to prevent such slimes. UNDER-WATER 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 temperature, and usually the rate of flow of the solution over the metal surfaces. There are other relevant factors,- but their influence 10 general is subordinate to those mentioned. Dissolved oxygen, acid 956 CHAPTER 43 ,...., 1954 Guide 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. If the metal contains film forming agents, such as chromium, nickel, and silicon, or if the water contains inhibitors such as silicates and chromates, corrosion may in some instances be minimized. '. . '} ' >' ; ' , " / Cold Water Services i- Where water from municipal supplies is used industrially in a closed system with little or no increase in temperature, it is seldom necessary or feasible to treat the water to reduce its corrosivity. When it is mandatory, the addition of caustic soda to maintain a pH over 11, plus the addition of sufficient sodium sulphite to maintain a residual of over 100 ppm (as Na^SOj), usually suffices to prevent serious troubles.' However, in some 5 cases the cost may be prohibitive. .V When the use of sodium sulphite or a comparable chemical for oxygen frremoval is prohibited, as in potable waters, the addition of small amounts of lime to maintain a Langelier Index (see Fig. 4) of 0.5 or more may prove helpful. In systems exposed to the atmosphere, as for example air washers or storage tanks, both laboratory14 and field tests15 have shown that the addition of alkalies to maintain a pH greater than 8.5, plus the addition of other chemicals that produce protective films on the metal surface, will measurably decrease corrosion. Sodium dichromate, sodium silicate/ and tri-sodium orthophosphate have been shown to be effective film formers in rc the order mentioned. Caustic soda is usually used to raise the pH value, and sodium dichro- > mate is most often employed as a film former in industrial waters. In old y systems, not previously inhibited, about 500 ppm of sodium .dichromate. y; are usually maintained at the start. After two or three months, and in, new systems, a residual of about 300 ppm of dichromate usually proves, effective. When insufficient dichromate is employed, pitting, is sometimes, "p. accelerated. Aeration does not impair the efficiency of dichromaies, but, yj does deplete the caustic soda concentration. ' In large industrial systems, the use of vacuum deaeration has . been? shown to be effective.16 In small systems, the equipment required can ' seldom be justified economically. ' ,' 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 ex-.~` pedient. Cement lined pipe and tanks suitably resist attack. Where the water contains slime-forming organisms, especially 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 sur/ faces, will measurably prolong the life of equipment handling cold waters/V Corrosion and Water Formed Deposits, Causes and Prevention 957 Hot Water Services As a usual thing, corrosion does not create important troubles when temperatures are maintained below 140 F. In closed systems where little fresh water is introduced, such as in a hot water space heating system, corrosion is usually negligible because the oxygen released in heating the water is purged through the vents. ', Where large amounts of fresh water are constantly entering and are being heated, the use of mechanical deaeration is the most universally satisfactory expedient to employ. Where the use of such equipment can not be justified economically, anti-corrosive chemicals, and the. use of corrosion resistant metals,-are the more practical expedients to be Used. Treating Chemicals. Alkalies, such as lime and caustic soda, silicates of soda (water glass), the poly-phosphates of soda, sodium sulphite, and sodium dichromate are usually used. Organic compounds, such as the glucosates, dextrines, and tannins are sometimes used, but their value is still a controversial matter. When any chemical is used, so many rele vant factors are involved that it is always advisable to seek adequate technical counsel in inaugurating the treatment. Very often, where such precaution is not taken, new troubles are created that are more aggra vating than the original difficulty.17. Silicate of soda is used to protect iron, lead, and brass water pipe.18 For most waters, a solution of Na20:3Si02 is recommended. Sodium sili cate, equivalent to about 10 ppm added silica, should be fed to the water for the first month after which it may be reduced to give 5 or 6 ppm added silica. Where careful control of the silicate feed is exercised, the water is not injured for domestic use by this treatment. The rate of corrosion of iron pipe has been reduced by 70 percent, and dezincification of brass pipe practically stopped, by this simple treatment. The amount required and the effect are not the same in all waters. . Pipe Materials. Brasses with 60 to 67 percent copper are dezincified in some corrosive waters, and in certain localities are not much more service able than galvanized iron or steel pipe. The zinc in brass pipes is leached out locally, leaving a plug of porous copper. The weakening of such pipe is especially noticeable under the threads. Dezincification is retarded by the use of silicate of soda (8 ppm added silica).19 In salt or fresh water, there is no material difference in rate of pitting of wrought iron, steel, low metalloid steels, or copper bearing steels. This is contrary to the relative performance of these metals in atmosphere. Refrigerating Systems Corrosion in refrigerating systems is confined to surfaces in contact with brines or those in contact with the refrigerant. Brines. Refrigerating brines usually are comprised of sodium chloride, calcium chloride, or calcium and magnesium chlorides. The corrosivity of dilute brines is higher than their more concentrated solutions. . The corrosivity of sodium brines, other conditions being fixed, is about 1.5 times greater than brines .of the alkaline earth metals. Brines are excellent electrolytes. Contact of dissimilar metals of wide potential differences, when in contact with brines, results in rapid corrosion by galvanic action. The leakage of air, acid refrigerants, or both, accelerates the corrosivity 958 CHAPTER 43 1954 Guide of brines. Ammonia precipitates calcium and magnesium salts, thus clogging the system at restricted points.. .. The addition of caustic soda and sodium dichromate to brine solutions to inhibit corrosion of iron, is a more or less general practice. Sodium sili cate and sodium phosphate are also used at times, but tests indicate they are not as effective as is sodium dichromate. It has.been suggested20 that 125 lb of sodium bichromate per 1000 cubic feet of calcium chloride brine, and 200 lb per 1000 cubic feet of sodium chloride brine, be added to inhibit brines; that when salt or calcium chloride is added to "strengthen" brine, sodium dichromate also be added in the amounts shown in Table 7. : Refrigerants. The common refrigerants, except those of the hydro carbon type, will attack the common metals and alloys if moisture is present. "Even a very small amount of water may cause severe corrosion Table 7. Quantities of Sodium Dichbomate to be Added to Maintain Initial Concentration Brine to be Strengthened : . 1.16 1.18 1.20 1.22 1.24 1 1.12 1.14 1.16 1.175 Lb Sodium Dichromate per 100 lb CaClt Added 0.695 0.621 0.556 0.502 0.455 Lb op Sopium Dichromate per 100 lb NaCl Added 1.79 1.47 1.32 1.18 with certain refrigerants. The. amount required need only be sufficient to produce a water film on the metal surface. ' With the halogenated hydrocarbons, complete elimination of water is. much to be desired. Where ammonia is used, copper and its alloys, aluminum and zinc, are attacked especially at elevated temperatures. When sulphur dioxide is used, more than 5Q ppm (0.005 percent) of. water will cause appreciable corrosion of virtually all the common materials. Minimizing Condensate Corrosiveness There are four expedients that may be utilized to minimize corrosion in steam condensate systems: (1) treatment of the boiler feedwater so as to eliminate deleterious gases entrained with the steam, (2) design of the condensing equipment to minimize dissolution in the condensate of the deleterious gases entrained with the steam, (3) chemical treatment of the condensate, (4) use of resistant metals. Boiler Feedwater Treatment. Elimination of oxygen from boiler feed water and, therefore, from the steam developed, can be accomplished either mechanically or chemically. In some steam generating stations, both expedients are employed. Tests" have indicated that in small low-pressure heating boilers, where the boiler input contains less than about 50 ppm of carbonate hardness, Corrosion and Water Formed Deposits, Causes and Prevention 959: the CO, in the steam can be controlled by adding calcium hydroxide to the boiler. In Fig. 5 are shown the equilibria conditions proposed for* boilers operating at pressures up to about 5 psi gage. This 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: feedwater consists of removing the alkaline earth salts; i.e., softening, and subsequent acidulation followed by deaeration at.tempera-; tures near the atmospheric boiling point of water.22 ' . Design of Condensing Equipment. In the design of water heaters and comparable types of condensing equipment,22 it is possible to shift the' accumulation of non-condensible gases to a location away from the con* densate level and, subsequently, vent these gases to the atmosphere. Fig. 5. Relation op Htubate/Carbon ate Content in Hard Boileb COWater and i in Steam at About 5 Pei Operating Pressure (All analytical values are ppm by weight) Venting 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 in coming steam is below about 5 ppm. When the steam contains more than 5 ppm, 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 containing compara tively large amounts of oil, are practically non-corrosive, due to the pro tective film provided by the oil. When oil is intentionally added to con densate,24 inadequate quantities may accelerate rather than decelerate corrosion on those surfaces not covered by the oil. Sodium silicate added t CO,-bearing condensate has been shown to decrease, but not entirely prevent, corrosive action. It is not definite whether the protection horded by silicate solutions is due to the establishment of a protective r 960 CHAPTER 43 r ; - 1954 Guide film on the metal surface or to neutralization of the GOn by-the alkali in 1 the1 silicate solution. 1 ' It has been postulated that ammonia,28 cyclohexylamine,26 ethylene ` diamine, and morpholine27 will retard corrosion of condensate lines. - Tests . with benzylamine have also been reported.28 - 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 tests29 indicate that this salt accelerates rather than decelerates, the rate of attack of steel by condensate containing CO2 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 to which the steam or condensate is put. . Use of Resistant Metals. For economic reasons, the metals known to resist corrosion can seldom be used exclusively for condensate lines in any Fio. 6. 10Comparative Corrosion Resistivity of Materials Exposed to Condensate sizable enterprise. Nevertheless, there may be instances where the use of a limited amount of the more costly, but resistant, materials can'-be justified. The data in Fig. 6 are the results of tests30 designed to reflect1 the corrosion resistance of the more commonly used metals to attack by condensate containing oxygen and COj. , . ;1. 1 In contemplating the use of a resistant metal, as a section of a conden15 ' sate line, it should be remembered that, if other conditions are right}' corrosive attack will merely be transferred down stream in the system-' Galvanic corrosion resulting from the contact of dissimilar metals in`a'' condensate line seldom occurs. No paint or similar protective coating. has thus far proven satisfactory. Tests of cement lined and vitreous- ' lined pipe have shown the linings to be readily dissolved by hot con-j densates. ATMOSPHERIC CORROSION 'ti Most of the problems originated by atmospheric corrosion occur" connection with the fire-side of boilers and furnaces (including their fli Corrosion and Water Formed Deposits, Causes and Prevention 961 and stacks), sewer vents, air ducts, coal and ash handling equipment. Usually such equipment is fabricated from common types of ferrous metals. Generally little or no atmospheric corrosion occurs at temperatures 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 atmosphere, will dissolve in the hot liquid, but sulphur gases may dissolve and cause rapid attack. Oxygen, sulphur dioxide, sulphur trioxide, and carbon dioxide are the deleterious gases most frequently accountable for corrosion in moist atmospheres. Coal Storage and Handling Equipment Virtually all coals contain sulphur in the form of pyrite, and some moisture. In storage, the pyrite is likely to be decomposed by oxidation. Moisture dissolves the products of decomposition forming sulphurous and sulphuric acid. The acid solutions vigorously attack the supporting metal. Rubber linings have been developed for coal chutes and bins to ef fectively resist corrosion and the abrasive action of the coal, but they are expensive.31Concrete linings for steel bunkers have also been ef fectively employed .32 `' The use of high chromium steels is not always a. sure cure, especially with coals treated with dust allaying agents high in chlorides. Flues, Stacks, and Fire-side of Boilers 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, how ever, be subject to attack during the warming-up period of an appliance, or when the rate of operation is so low that the temperature of the flue gas is below the dew-point. It is common practice to use cast-iron or acid resistant vitreous enameled steel in flue gas connections to appliances, to prolong the life of these parts. The shut-down period, when condensation of moisture occurs on the metal surfaces, is usually the time when most damage is done.33 In those sections of the stacks where flue gas tempera ture drops below the dew-point, corrosion is inevitable during operation. It is clear that where long shut-down periods are anticipated, a practical method for mitigating corrosion is to clean the surface thoroughly and to provide adequate clean, dry air circulation to prevent condensation. (See also Care of Idle Heating Boilers, Chapter 16). Protective coatings with organic binders are destroyed rather rapidly above 400 F because of the decomposition of the organic materials: The surfaces of metals, whose temperature does not exceed 400 F, may be pro tected by periodically applying paints such as those specified in the fol lowing paragraphs entitled Air Ducts. Air Ducts The most practical method for protecting air duct surfaces made of steel from atmospheric corrosion, is to apply protective paints. One of tee most effective protective coatings 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 962 CHAPTER 43 1954 Guide be red lead paint tinted to a black or brown color, black paint made according to Federal Specification TT-P-61, red iron-oxide paint con forming 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. BURIED PIPE LINES Lines that are cold and in intimate contact with the earth are corroded from the same causes as in mineral waters, but pitting is usually more intense due to variations in concentration of- salts and oxygen in solution, acidity, drainage, and presence of solid materials (such as cinder) in contact with metal pipe. Galvanic currents, induced by contact of certain dis solved constituents in the soil, often act over a large area, and accelerate corrosion where they leave the pipe line. Certain bacteria that thrive in the absence of oxygen have the power to obtain hydrogen and dissociate sulphates in the soil, with a resultant pro duction of hydrogen sulfide which attacks the iron to form iron sulphide- Stray electric currents, from electric power generating stations some times find their way into buried steel structures, and do damage in pro portion to the current density where the current leaves the metal to enter the ground. Pipe Materials Under many conditions where steel would be corroded, the use of corrosion-resistant metals other than steel may be desirable, even if greater in first costs. Wholly austenitic stainless steels are very resistant to under ground corrosion. In most environments copper, red brass, and coppersilicon alloys will resist corrosion and may, at times, be used to advantage. However,84 soils with a high content of organic matter, or alkaline soils in which the ratio of chlorides and carbonates to sulfate is high, may be corrosive. Copper should not be embedded directly in cinders or in tidal marshes where it may be subjected to attack by sulfur compounds. Lead85 corrodes chiefly in soils deficient in oxygen or containing cinders. Because lead is corroded to a considerable extent in most soils, lead coatings applied to steels are not adequate for underground use. ' Galvanized iron pipe will resist corrosion for various periods of time, depending on the soil and how long the galvanized coating lasts. The zinc used for the galvanized coating, is on the electrochemical protective side of the iron, and the zinc is corroded and changed to zinc compounds before the iron is attacked. This accounts for the protection afforded by gal' vanized iron. Even if some protection is obtained, eventually the gal vanized coatings are destroyed by chemical action and the corrosion of the steel begins. Protective Coating Protective coatings for buried pipe lines are in a class by themselves because of the unusual service conditions, and because it is not possible to Corrosion and Water Formed Deposits, Causes and Prevention 963 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 oyer a standard priming coat such as red lead or a bituminous paint, and for long service it has been found that after the bituminous coatings' are applied, a wrap ping 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 maintained. Cathodic Protection . Protection is obtained by rendering the' structure cathodic to the sur rounding water or soil by means of a controlled difference of potential. This method, which has proved satisfactory 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. Protective coatings that insulate a large portion of the metal surface will reduce very materially the total amount of protective 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 conductivity 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 obtain an accurate estimate of the minimum current density required. The current is then controlled by the potential between 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.86 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, lime, and concentrated sulphuric 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 concentrations used in water conditioning, have been reported87 to produce dermatitis. Chromltch is not uncommon among workers handling chromates. The amines are said to be absorbed through the skin.88 Morpholine is said to cause kidney and lung trouble when so absorbed. Chlorine gas irritates the skin, eyes, and mucous membranes. Concen trations as low as 0.004 percent by volume in air cause dangerous illness w 0.5 to 1 hour. When relatively large amounts of the non-gaseous chemicals are to be handled, protective clothing, including goggles, should always be pro- 964 CHAPTER 43 1954 Guide y vided, and a shower head or its equivalent provided at or very near the point where the chemicals are mixed. Chemicals should alwayi be washed from, the skin with large volumes of water. For the handling of chlorine and chlorinators, the U. S. Public Health Service33 stipulates the following safety requirements: . 1. Suitable gas masks and a small bottle of ammonia for testing for leaks should be kept at convenient points immediately outside the room or enclosure in which chlorine is being stored or is in use. Gas masks should be inspected at regular inter vals and kept in serviceable condition. Note:--All-purpose masks offer adequate protection only when the concentration 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. The room or building housing chlorinators 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 in dustrial plants, is required to meet drinking water standards insofar as bacteriological quality is concerned. A ruling of the U. S. Department of Agriculture, Meat Inspection Division, prohibits the use of chromate in water used for air washing when the air later contacts foodstuffs.40 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 ordinance41 now in effect in Detroit, Michigan,- which stipulates in part: i "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 flow of polluted water by an atmospheric gap. Secondary supplies and emergency sources shall include: surface waters from rivers, lakes, ponds, lagoons, and reser voirs; 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 bacteriological 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 sub stances with deleterious physiological effects, shall not be allowed in the water supply system." ' The same agency recommends that the concentration of the substances: listed be held below the values cited in Table 8. 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.40 While their action is not binding, prudence dictates that no form of treatment should; be used that will result in raising the concentration of the substances listed, above the value cited. Since virtually all of the permissible chemicals used for scale, slime, and, corrosion control have deleterious, physiological effects if taken internally Corrosion and Water Formed Deposits, Causes and Prevention 965 Table 8. Recommended Maximum Allowable Content in Wateb Supplt` SutfbiANCS ^ Majc ' t/ONCZS TSATION, ppm SunalANCX n Max Concentration, ppm Copper..................................... Iron & Manganese (Total).. Magnesium. ........ ........ Zinc........................................... Lead.......................................... Fluorine................................... 3.0 0.3 125.0 15.0 0,1 1.0 Selenium............. .. Phenols (Total)..................... Poly-phosphateofSodium.. 0D5 0.05 0.001 10.0 10.6 V. S. Public Health Service. 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, the feeding device shall automatically cease operating." REFERENCES , 1 Annual Report (1947) Committee D-19 (American Society for Testing Materials). * Corrosion Handbook, edited by H. H. Uhlig (John Wiley & Sons, p. 27). 1 Discussion, Corrosion and Material Protection, May 1945, p. 2. ' , \84)'Sllt,I'hble Discussion on Organizing the Classification of Industrial Waters, 10,M , Schroeder (Proceedings, American Society for Testing Materials, Vol. 44 p. 1051). w SnyP.ic$ Water Analyses for Classification with Reference to Industrial Use, by n TOwi 1 mS (>rocee(bn88> American Society for Testing Materials, Vol. 44, 1944, uuuuuiliu m-oso--11 \American society jor t esting materials). on Preventing Solution of CO. in Condensates, by E. W. Guernsey lA.b.H.V.E. Transactions, Vol. 51, 1945, p. 69). * Studies of the Mechanism of Solution of CO. in Condensates Formed in Steam 1945'pg 39)StemS f BuiIdinBs> by L- F- Collins (A.S.H.V.E. Transactions, Vol. 51, * The Analytical Control of Anti-Corrosion Water Treatment, by W. F. Langelier yournal, American Water Works Association, Vol. 28,1936, p. 1500). "rf,ace-Active Properties of Hexametaphosphate, by G. B. Hatch and Owen (industrial and Engineering Chemistry, Vol. 31, 1939, p. 51). (P ' Sbnie Control in Cooling Equipment with Phenol Derivatives, by J. A. Holmes 1944 Cp glgS' Annual Water Conference, Engineers' Society of Western Pennsylvania, "Tuberculation of Mains as Affected by Bacteria, by H. G. Reddick and S. E. `merman (Journal, New England Water Works Asscoiation, Vol. 46, 1932, No. 42). On ^jhrebiological Anaerobic Corrosion of Steel Pipe Lines, by R. F. Hadley (The wand Gas Journal, September, 1939). Tests of Corrosion Inhibitors for Water Treatment in Air Conditioning Equip- .966 CHAPTER 43 . /- 1954 Guidei* ment, by James H. Wilson and E. C. Groesback (Research Paperl305, National Bureau of Standards Journal of Research, Vol. 24, 1940, p. 665). ! " The Control of Corrosion in Air-Conditioning Equipment by Chemical Methods," By C. M. Sterne (Proceedings, American Society for Testing Materials, Vol. 38, 1935, Part 2, p. 261). 11 Cold Water Vacuum Deaeration, by S. T. Powell (Proceedings, Water Confer ence, Engineers' Society of Western Pennsylvania, 1945, p. 51). 17 Corrosion--Causes and Prevention, by F. N. Speller (McGraw-Hill Book Co., 1951, pp. 805, 905, 910.and 912). 77 Corrosion Control with Threshold Treatment, by G. B. Hatch and Owen Rice (Industrial and Engineering Chemistry, Vol. 32, 1940, p. 1572). 77 Refrigeration Data Book (American Society of Refrigerating Engineers, 1936, p. 404). "Engineering Problems of Water Treatment, by.L. F. Collins (Power Plant ' Engineering, Vof. 50, July 1946, p. 78-81,120): . . 81 See p. 470 of Reference 18. , 77 Studies in The Detroit Edison'Co. (Unpublished); , 71 Preventing the Solution of COi in Condensates by Venting of the Vapor Space of Steam Heating Equipment, by D. S. McKinney, J. J. McGovern, C. W. Young and L. F. Collins (A.S.H.V.E. Transactions, Vol. 51, 1945, p. 53). 14 Corrosion in Steam Heating Systems, by Leo F. Collins and Everette L. Hender son (Heating, Piping and Air Conditioning, October 1939, p. 620).' ' 77 U. S. Patent 1,395,730. U. S. Patent 2,053,024. 77 U. S. Patent 1,903,287. " Treating Steam Chemically to Reduce Return Line Corrosion, by A. A. Berk {Industry and Power, Vol. 53, Nov. 1947, p. 79). ` 77 Tests in The Detroit Edison Co. (Unpublished). * More Information Concerning Corrosion in Steam Heating Systems, by L. F. Collins (Proceedings, Water-Conference, Engineers' Society of Western'Pennsylvania, 1943, p. 37). ...... 11 Rubber Linings and Coatings, by J. J. McNeil (Corrosion and Material Pro tection, March-April, 1947). 17 Protection of Steel Bins from Corrosion, by J. V. Schaefer {Power Plant Engi neering, Vol. 26, 1922, p. 632). i "Some Notes on Corrosion of Cast-Iron Sectional Boilers, by E. R. Walters {The Institution of Healing and Ventilating Engineers, Preprint, 1944). ' 74 See p. 67 of Reference 2. 77 Soil Corrosion Studies, 1941 by K. H. Logan and M. Romanoff {National Bu reau of Standards Journal of Research, Vol. 33,1944, p. 145). '. 77 Cathodic Protection of Steel Equipment Submerged in Water, by L. P. Sudra- bin (Proceedings, Water Conference, Engineers' Society of Western Pennsylvania, 1944). ; 77 A discussion by D. W. Haering (See p. 66 of Reference 11). 78 Cyclohexylamine and Dicyclohexylamine, by T. S. Carswell and H. L. Morr7^ {Industrial and Engineering Chemistry, Vol. 29, 1937, p. 1247). 77 Drinking Water Standards, etc. (Reprint No. 2440, Public Health Reports, Vol. 58, No. 3, January 15, 1943). 40 Discussion of Ref. 15, by R. M. Palmer. 47 Official Plumbing Code of the City of Detroit, Article V. 47 Private Communication from H. S. Jordan, A.W.W.A. CHAPTER 44 OWNING AND OPERATING COSTS Fixed Charges: Amortisation, Interest, Taxes, Insurance, Rent; Maintenance Costs; Labor for Operation; Energy and Water Costs: Operating Refrigerating Equipment, Condenser Water, Heating THE total cost for the use of heating, ventilating, and air conditioning systems may be divided into two classifications. The first of these is the relatively fixed and unvarying expense of ownership, and the second is the variable and somewhat controllable expenditure for actual operation of the equipment. Owners and prospective purchasers of this equipment are particularly concerned with both since the actual expenditure is gen erally predicated upon the possible return on the investment resulting from increased patronage, greater efficiency on the part of the employees, meeting of competition, or the improvement and maintenance of quality in a manufactured product. These costs may be grouped under four headings: (I) Fixed Charges, (2) Maintenance Costs, (3) Labor for Opera tion, and (4) Energy and Water Costs. - FIXED CHARGES Fixed charges are the annual expenses arising from the ownership of the. installation, including use of the owner's money, and protection of the equipment in the form of insurance. Such costs are usually unchanged from year to year regardless of whether the equipment is in or out of serv ice. Fixed charges may be grouped under five headings: (1) Amortization, (2) Interest, (3) Taxes, (4) Insurance, and (5) Rent. Amortization 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 uppn (I) 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 represents the first cost of the equipment combined with additional costs incurred because of the installation of the system. The first cost of air conditioning, heating, or ventilating systems includes the following: . 1- Heat producing equipment including boilers, burners, controls, etc. 2. Heat distributing equipment including direct radiation, piping, etc. 3. Air handling equipment including fans, air heaters, air conditioners, filters, controls, etc. 4. Air distribution system including ducts, outlets, grilles, etc. 5. Refrigerating equipment including piping, pumps, etc. 6. Water conservation devices including towers, evaporative condensers, etc. 967 968 CHAPTER 44 1954 Guide; eo o 5fc hn P$ SSS agn eng 5s 55 <s2 BOgO gOgh 3H gg H 190.00 165.00 120.00 9 0 .0 0 60.00 62.00 6 0 .0 0 48.00 4 6 .0 0 44.00 42.00 40.00 :: :___j ts % S.'S D P - Z*\ < fa = A 1 O O 0 0 O i. oz & 3 o 0 O*. at eZ BH < P er T on F eb Sq Ft Floor a & 0H . Ph S5 'so $| oo O a5 H W<S 1tOO-i gPDeS JOK< 503 O 3HO ss H .a . sgHa 0 AS -86 r* H H CO Z S Sa g& * & 0 - <e.a< aa a au& o b* . z o H K a n a o Q E0-3* O c* Q B , OS bBH* Or?* 15 5a MOS -a go SM B < < < bOOJ* cs g , a" PD *< - H Pi EFRIOB ATION T ons ---------------1 8,333 12.500 16,666 25.000 25.000 37.500 33.332 50.000 50.000 75.000 66,664 100,000 83.333 125.000 100.000 150.000 133,328 200.000 166,666. 250,000 U n it C osts 1 .0 5 0 .9 8 0 .9 5 0 .9 2 0.91 0 .9 0 0 .8 8 0 .8 6 0 .8 4 0.82 13,100 24,500 35,700 46.000 68,200 90.000 110,000 129.000 168.000 205,000 19,350 35,700 61,600 66,400 . 97,400 128,200 156,800 183,600 234.000 284.000 775.00 730.00 690.00 664.00 650.00 641.00 628.00 612.00 585.00 568.00 2 .3 2 2 .1 5 2.07 1 .9 9 1.95 1.93 1.88 1.84 1 .7 6 1.71 1 .5 6 ' 1.43 1 .3 8 . 1.33 1.30 1 .2 8 1.25 1.23 1.17 1 .1 4 s >> 3a 45 . i &. ? -I A & O. * .s"S *o .I*|a 1 is os a, s 9 * 3 s > *- J- 3-b9O . g l^a's -j g.a| 6,250 11,200 15,900 20,400 29.200 38.200 46,800 54,600 66,000 79,000 ONtACN'f4W<N-'ON'SG'H)lDOCOrtqOHNONHOUCHJOCkOOH S?St-h8--S c8i o|iBn 88`O 3 ' O Qo oa 3 .s III d- t2 i3 ll5!*3 5ig-a 'C-o, S3 5* a 2' --= lsi$S-*a*5'35ad* ooi*uds.Z-ej*sl * . - .. S ; `i *Ti .' "S"{aj*ws3'dfl 8- as S$%^ W1 (wC ,, o a-S2. |sagi;! - 8sssl=g .8 5 S2i`3S-I-a23Iasg3ko! * oo 8 Owning arid Operating Costs > -- 969 7. Insulation of pipes, ducts and equipment. 8. Building alterations, furring-in ducts and pipes, structural work, etc. To estimate the first cost of any system prior to installation, the best procedure is to determine the heating and cooling load, and then after thorough engineering study; select the type of system. The installed cost of systems will vary widely, depending , upon the type of equipment se lected, and the design of the distribution system, equipment and labor costs in the locality, demands for the particular installation, etc. A trea sonable approximate' cost may be determined for a selected design in a given locality from the sum of the estimated unit costs of the component parts of the system. A reasonably precise estimate of the cost of the com ponents may be obtained from cost records of recent installations of a comparable design, or from quotations submitted by manufacturers and contractors. . Approximate costs are given in Table 1 for mechanical air handling sys tems including heating and cooling coils for distributing cfm per square foot of floor area and refrigeration equipment based upon a requirement of one ton for every 333 sq ft of floor, area. Different types of service de mand may change the floor area per ton of refrigeration and air .volume per square foot between wide limits and, consequently the table should be used with caution. Other first costs may be incurred because of the installation of the air conditioning or heating and ventilating system. These will include such items as electrical work, plumbing, miscellaneous piping, building altera tions, cutting, patching, furring-in of ducts or pipes, foundations, struc tural supports, remodeling or redecorating after installation, consulting engineer's fees, licenses, and permits. As these costs vary widely no ap proximations are practicable. Therefore, each case must be considered individually. If a quotation can be secured from a manufacturer or con tractor covering the complete job, it will usually include the items Which have been mentioned. The length of the amortization period to be used depends upon (1) the type and remaining life of the building or space for which the system is to be used; (2) the type of equipment to be employed as a part of the sys tem; (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. Maintenance and deterioration usually have the effect of offsetting one or the other. If a long deprecia tion period is to be used, then the item for maintenance, repair, and the replacement of wearing parts must be greater than for a short deprecia tion period. In determining the length of. the amortization period, the owner's ac counting practices will have considerable bearing upon the number of years used in the calculation. 1 For taxation purposes, this period depends upon the use and the service to which the equipment is placed. At the present time indications are that varying interpretations on depreciation will 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 970 CHAPTER 44 `4954 'Guidei*' referral to Schedule F which is issued by the Bureau of Internal Revenue ' and summarized in Table 2. ' ' , _ Interest \.v _ ' ...., ... '\ ^ i The interest charged to the cost of ownership may be. based upon the average interest rate for the peripd during which the first cost of the equip-1 ment will be amortized. While some ' accountants do not include , interest in the annual fixed charges and consider it amegligible 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 " Table 2. Pbobable Useful Life of Equipment* Life-in Years 1. Heat Producing Equipment . - ..... (0)' Boilers. . ..............-- ................................................................................ .(b) Stokere and burners-............................................ ----------:--------....... ' 20 : 20 ,, 2. Heat Distributing Equipment ' : -. (0) Piping-7-copper.;..................................................................................... . -- ;* v-.; '' (bj Piping-^iron. i......................................;......................................'-------'............................. . (cj.Radiationr^oncealedi.-.......................................................................- v ..............*...................... (e) Valves and specialties...........................................................................................-.................................... ' ' - same as bldg. : 20 25 ' 25 10 ! -b 3.iAirTIandling Equipment .. * f (6) Heating and cooling coils..................................................................................................................... ' . (c) Spray humidifiers and idehumidifiers.........-.................................*:*.?.............................. (d)` Fans....................................................................................................................................................................... (e)iAir conditioning units.......:............................................................. -.............................................. (?) ` Electrical starting equipment................................................. .. ........................................................... (A) Pneumatic control systems....................................................... ...................... ....................-- (i) Electric control systems.............................................................................................................................. -20 20 10 ' 15 : 10 20 20 15 15 ; ;j ;l - 4. Air Distributing Equipment . . . _ .- " (d) Ductwork:....................................................................................................... -......................'.....................: (c) Duct insulation......................................................................................................................................... ' same as bldg. ' 20 15 - 1, ;. 5. Refrigerating Equipment _ - , - (b). Reciprocating refrigerating machines...................... v.............................................. - (c) Motors and starters.................................................................................................................................' (d) Piping--copper...................................,.......................................;,:.............................................r (e) Piping--steel-................................................... .................................................................................. ............... : (/) Pumps...............................'.................................---------------------------------------------:..:-------'.......................... , '. 20 20 V 20 20 20 . 20 'U 6. Water Saving Devices (0) Evaporative condensers-- .............. -. ...........................--........ (b) Cooling towers.................................................................................................................................................... 15 ' 15 . .(c) Welb..........................................................................................-..............................................:..................... 25 * Taken from U. S. Bureau of Internal Revenue Schedule of Probable Useful Life, revised 1942. , - :. . , - - -if j'l'i . purpose of making the installation. Whether it is borrowed or taken from surplus funds, the money that might have been earned as interest is prop erly chargeable to the operation of the system'. ,, The formulas for computing interest and amortization are given in Ta ble 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 which may be charged to the property as a result of the im* provement due to the installation`of an air conditioning system wiIkvary according to the practice of the official agencies levying property taxes. Owning and Operating Costs ^971 Insurance ; " ' . ' | Insurance against losses by fire is ordinarily secured by increasing the building fire insurance coverage to coyer all or part of the first cost, of in stalling the air conditioning and other mechanical systems. Various;types of extended coverage are available for protection against a dumber of other types of losses. ' 1 . . . Boiler insurance may be extended to coyer the air conditioning equip ment to protect against losses dunto explosion, 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 owner's business, the rates are usually set by rating qrgamzation^specializ- T^ble 3. Owning and Operating Cost First Cost . . Annual Service Coot Cost of mechanical system............ .. . . Other costs........................................ i... First Cost (FC)--Total. :--. Annual Fixed Charges I Amortisation--Depreciation period Y years.................... Interest rate i%....................................... Amortisation and Depreciation FC Y *.................................................. Interest: --2y 1 X i X cost =* .......... Taxes............................................................ Insurance.................................................... Rent.............................................................. Annual Fixed Charges: _ (Total).............................................. Annual Maintenance Costs Replacement or servicing of air filters.................................................... . Outside Maintenance service.............. I Water Treatment..................................... . Lubricating oil and grease--........... Painting for corrosion protection or other purposes....................................... Replacement of worn parts.j Refrigerant................. ............................. . ( Wages of engineer or operator.......... : i Annual Maintenance Cost--- . ! Total......................... ::.................| Electric Power.Costs .: , ' : ' i Fans..................................... !......... .. ----------------- Pumpe--Chilled water..i'....I.-..': ^ Pumps--Condenser water.............. - Pumps--Well water........................... -- -- - Cooling tower fans......... - Cooling tower pumps.......;........ ......................... Refrigeration machines....... ........... ........................ Miscellaneous or other........................ -- Gas............................................................ Coal..................................................... .. .......................... Oil--for boilers or Deisel,engines...-------;------- -- Steam .> For Direct Heating...................... ................. For Ventilation--preheaters:. . i; --- - . For Ventilation--reheatere.1..-- ------------- - For Turbine driven equipment... ' ;-- For Engine driven equipment.. 1: --1------- --- Sewers ' - Charges for discharging water into public drainage systems... --:-------------- Condenser water.......... ............. *. Annual Service Costs: v *. Total.................... .......... .......................................... . SUMMARV Annual Fixed Charges.......................... --; Annual Service Costa...................... ,. -tAnhuaTMaintenance Costs......... -7-- Annual Owning and Operating . Costs--Total.......'.......... -- 1........... ......... dig in this work. Exact figures on insurance cannot be determined with out 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. . ., . ; - . lunixi woio 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 eliminating 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 972 CHAPTER 44 1954 Guide extend to other facilities beyond the equipment being discussed here, it is important that only an equitable share of the group's time be charged to maintenance. . Extraordinary repairs are quite often handled by separate maintenance divisions and the expense charged back to air conditioning, heating, and ventilating. In other cases, all maintenance is handled by outside service firms and the cost considered as maintenance. These costs vary to such an extent that the type and cost of the purchased equipment may deter mine the amount of maintenance necessary. 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. The. accounting practices of the owner and the rules of the Bureau of Internal Revenue affect the charges for major overhauling or complete re placement which may restore the capital value of certain equipment items. In these cases the expenditure may not necessarily be charged as mainte nance but will become a fixed charge spread over the remaining years of Table 4. Approximate Maintenance Cost for Large Air Conditioning Installations, Using High Quality Equipment " * . Dollars peb(Ton)(Yeab) Refrigerant...................................................................................................................................... Controls, outside service........................................................................................................... Cleaning air conditioners.......... ................................................................................................ 0.96 0.40 0.40 1.36 0.24 1.19 . equipment life. Table No. 4 gives some approximate costs for maintaining large air conditioning installations using high quality equipment. LABOR FOR OPERATION In some cases with the installation of automatic equipment, operating labor may be non-existent, but where such labor is required, the cost,is readily calculated. Where operators are required, the expense is often considered maintenance, but since they may have other functions which are not properly charged to operation of the air conditioning, heating, or ventilating installations'the charges should be properly allocated. The 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 horse power. Annual power cost can then be figured from the following formula ' 0.746(bhp)HR annual power cost = ------------------------ 0) Owning and Operating Costs t- ' ';? <'. '973 where ).'. : \ blip = brake horsepower. H = annual operating hours. . R = power rate, dollars per kwhr. i) = 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 struc ture is such that it is largely1 the demand charge which determines the proper value of E to use in Equation 1. ;, Table 5. Equivalent Full Load;.Opebating Hours ofRefrideration ... Equipment . Used for Summer Cooling Mat ; 15 to. Qct. 15* . Application HbOpen .FOB. Atlanta Business Chicago Detroit Los New. Angeles Orleans'/ Barber Shops........... Department Stores. Drug Stores.............. Funeral Parlors....... Restaurant (Short Hour).. Restaurant (Long Hour).. Specialty Shops (5 <fc 10) .. Theaters--Continuous........ Theaters--Neighborhood.. 1280 940 2100 600 940 1290 2100 1090 1500 900 . 1010 ` 840 ` 1630 440 . 870 970 1510 800 1010 640 /.650 '560' 950 300 560 535 820 530 700 420 720 . 610 1060 330 930 590 750 450 720 610 .1060 330 620 620 930 590 750 450 680 580* 980 310 580 ! 1080 890 1790 470 900 .s 570 1060 850 1690 560 860 720 1080- 430 650 Application Barber Shops........... Department Stores. Drug Stores.......... Funeral Parlors.. Offices................. .. Restaurant (Short Hour).. Restaurant (Long Hour)., specialty Shops (5 A 10).. theater?--Continuous....... Afiearers--Neighborhood.. HbOpen FOR Business New ' ' .York Phila- Oklahoma . DELPHIA': City St. Louis 1280 940 2100 '600 . 940. 830 700 . 1280 .... 370 . .710 . 860. 720 1330 , -380 . 740. 1290 2100 1090 1500 . 900 760 800 1170 1210 . 670 * 690 ' . . 850, s. , 870- ' 500'" 520 1020 . 840 1650 440 880 980 1530 810 1020 650 ' 770 ' 550 Wash ington D.C. .940 ,780 1530 410 810 1400. 750 950 . 580 * Modern Air Conditioning, Heating and Ventilating, by W. H. Carrier, R. E. Cbeine and W. A. Grant witman Publishing Carp. 1940, p. 73). .. .. Operating Refrigerating Equipment In an air conditioning system the refrigerating equipment is usually fhe largest power consuming item to be considered. Also, the prediction f operating cost is more difficult because 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 codling for the period of May 15th to Octo ber 15th. This table was calculated from the following equation: where B. = m(b -)- cf) (2) H. = equivalent full load operating hours of refrigeration equipment used for summer cooling during period May 15 to October 15. 974 CHAPTER 44 : '1954 Guide m total hours during period May 15 to October 15 that the establishment is open for business. l b = fraction of maximum load from internal heat under average operating con ditions. .. i ?s 4 V c = fraction of maximum load which is due to ext-ernal sources at maximum design conditions. iV, , .......... .. -/ = ratio of the number of hours for a particular city, when the outside wet- bulb exceeds 65 F, during the period June 1 to_October 1 to the total number of hours during that same period- Total1 hours are'assumed as 8 hr per day period for barber shops,-department'stores,` funeral parlors, offices, : short hour restaurantsi-and specialty shops,land 42rhr per dayiperipd for drug stores, long hour,restaurants, and theaters. . It should be pointed out that certain' southern citiehmay have seasons' longer than the 5-month period indicated in Table 5. If it is desired to consider a longer season of Operationy the ratio of! full load operating hours to hours open for business is smaller; in!'other words,'therefrigeration load factor is lower. This is true because the extra increment of days added will be a relatively light load, since the table already includes the more severe part of the season. The season electrical power cost for refrigerating equipment is then given' by the following equation: . 0.746 (bhp,) THe R season power costs = i) . (3)- wkere bhpt = 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.' ` ' Zf = equivalent full load refrigeration operating time, hours (from Table 5). R = power cost, including demand and energy charges, dollars per kwhr. , 17 = 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 may lead to large inaccuracies, in estimating operating costs, since there may be wide variations from year to year, and therefore, average yearly weather records should be used rather than those for any individual year. `. If the refrigeration compressor is steam turbine .driven, the, same general, method can be followed, taking into account average water rate per brake horsepower-hour and the cost of steam. ... Condenser Water i, , . .. . 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 pur chased, 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, and the gallons per minute per ton can readily be calculated for any water temperature rise. ' The following equation for cost of condenser water is useful: B = 0.060aTH'C (4) Owning and Operating Costs ; : : r -A h 975 wherei r; . .. . .... ... .... B = cost of waterforrefrigeration during period, dollars.' " a = average gallons per (minute) (ton). : , T = tons of.refrigeration at maximum design.load. ' -- B* = equivalent full load refrigeration operating hours (Table 5). C = water cost, dollars per 1000 gal. v " 1 ' i ; . >. The. average gallons per, minute per :ton must take into account the variable water , temperature. When, well water is used as :a; source, and entering, and leaying.temperatures are, considered constant, the,average gallons per. minute per ton. obviously are equal to the derign gallons per minute per ton:. . However, when the source is river or lake water, its max-1 imum seasonal temperature \yill generally be reached at the same time that Fig. 1. Typical Brake Horsepower Requirements for Refrigeration* cuDacitvT8. en '^."'Pns^tatwe of dichlorodifluoromethane reciprocating machines of about 25 tons bm m. k conditioning applications. Requirements of smaller machines are usually higher, and for coohL?''i it."*?' ^,aluea s5own "* !ot liquid refrigerant at condenser temperature (no sub- ftuSSiSSif the' liquid 0 3 * 0 5 the refrigeration load factor is highest. The average gallons per minute per wn should be calculated from known or estimated water temperatures, be cause they vary through the season. Maximum water main temperatures tv ^ven Chapter 35, but should always be verified locally. In lieu of this tedious work, the average gallons per (minute) (ton) may be taken as percent of design gallons per (minute) (ton) with reasonable accuracy, mr the condition of variable temperature of entering water obtained from nvers and lakes. . Cooling towers and evaporative condensers virtually eliminate condens es water charges since the windage and evaporation losses are seldom over wo or three percent of the water circulated. The savings in water consumed often times will not in itself justify the 976 CHAPTER 44 1954 Guide installation of water economizing equipment since the cost for pumping and the fixed or ownership charges may be in excess of the annual cost for once through condensing operation. If operating costs are to be the basis for selection, then fixed charges should be determined when studying ap plication of this equipment which usually has a shorter life than the other components. '. ,, Usually the primary factors influencing the installation of water con servation equipment are the lack of an adequate water supply or;local regulations intended to conserve an existing water supply. . ;" ; Another factor influencing the installation of such equipment- is the in creasing trend toward the enactment of taxes and service charges; for con densing water wasted into city sewers. Certain miinicipalities wil] remit the sewer taxes or service charge if the condensing water is submetered and discharged into a storm sewer or used for process purposes. Heating; j ;;.: The method of estimating fuel consumption to balance the building heat loss is given in Chapter.18, 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 less than the estimated quantity of out side air in cold weather should be considered in its effect in lowering fuel consumption. In addition, the heat required to accomplish winter humid ifying must not be neglected, when this feature is included in the equip ment. ' ' - ' ... . .. ' BIBLIOGRAPHY ^ Modern Air Conditioning, Heating and Ventilating, by W. H. Carrier, R. E. Cheme, and W. A. Grant--Chapter IV {Pitman Publishing Corp., 1950). Predicting Operating Hours of Refrigeration Equipment Used in Air Condition ing, by W. A. Grant (Refrigerating Engineering, July, 1941). : Cost of Operation of Refrigeration Used for Air Conditioning, by R. E. Cherne (Refrigerating Engineering, December, 1943). ................. . CHAPTER 45 INDUSTRIAL AIR CONDITIONING General Requirements for Manufacture; Processing and Preservation; Design ConV; ditions and Application Data; Classification of Problems; Moisture Content and; Regain; Conditioning and Drying; Chemical and Biochemical Reactions;.. ;! Crystallization; Control,?01, 2M*a4chining, Polishing, and for Static Elec- , . , tricity Elimination; Laboratory Conditions; Calculations; Safe- > guarding Health and Maintaining Safety; Contaminant Con- . : ; : i trol; Dilution Systems for Contaminants; Heat Storage; , Radiation; Local Relief and Spot Cooling; Odors .. INDUSTRIAL air conditioning is concerned with the design and ap-; plication of equipment for obtaining proper conditions for (1) the; manufacturing, processing, and preserving of material, equipment, arid commodities; and (2) mniR^h^S-the health, safety and efficiency of workers. This chapter included a general discussion of these conditions and also a comprehensive list of specific requirements for various types of products. ' : ' . ' /;' `. GENERAL REQUIREMENTS FOR MANUFACTURE, PROCESSING AND PRESERVATION In order to apply air conditioning to industrial processes, the air condi tioning engineer must have a thorough understanding of the processing problems involved; individual processes and machines 'are changing rap idly, and air conditions must be revised constantly to meet the new conditions. . Table 1 lists the temperatures and relative' humidities required for storage of certain commodities, and for manufacturing 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 affect Workmanship, uniformity and the cost of production.' Sometimes, a compromise between the known optimum condition for processing and that required for worker comfort is unavoidable. Air conditioning for industrial processes is so extensive and involved that a detailed treatment is beyond the scope of this chapter. It is possible to cover only a few salient points of the general subject. In many in dustries the exact conditions to be maintained are determined and known only by the manufacturer who specifies them. In other industries there ls a Wide variance between manufacturers' requirements, depending on results desired, experience, and cost considerations. ...... CLASSIFICATION OF PROBLEMS In general, any industrial air conditioning problem in processing may he classified under one or more of the following: 1. Control of regain. ...... 2. Control of rate of chemical reactions. . 3- Control of rate of biochemical reactions. 4. Control of rate of crystallisation. Control of temperature for close tolerance machining and grinding. 977 978 CHAPTER 45 1954 Guide Table 1. Temperatures and Humidities Applicable to Industrial Air Conditioning*. . Process Temp. F j R.H. % .. , - . : : BAKERY i? .* ' ** ` *' Mixer (bread dough)................................................................... Fermenting................................................................................ 75-80 . .. . \ 75-80' ' ' " 92-96 . 40-50 . . 70-75 80-85 .s Bread oven.................... ............. ................................................. ; .... 375--450 i Bread cooler (room or tunnel) Vacuum 28.6 m-................... Cold room------------- .................................................................. Make up room.-.V,..-/.i.;........ ------- ..... : Cake mixing (Bpon$e);.............................................. . 40-45 75-80 , - 70-75 60-05 go-65 '' . : : '- ' ' : . 65-70 . 65 -.: : 50 .'' . : 60-65 Dried ingredients, storage...................'................ .................- - - Fresh ingredients, storage................................................................ 70 30-45 65-80 Shortening (depending on type), storage........................... .... : - .,.4.5-70; 8ugar, storage................ ..................................................... Water* storage......... ..................^...................................... Wax paper, storage............. ;............................................... .............. 32-35 70-80 55-65 - 80-85 50-65 ...i/.. .: 55-6355 ' v...- . . 40-60 - . . ; .. . . U ....... r --- T .... 1 METHODS of mixer cooling ' ... ^* ; \ ... . I. 35-40 P water circulated through mixer jacket . . 2J .15-26 F brine. il: ; l' .' . . . , . . . .. 3. Direct expansion, refrigerant circulated through mixer jacket. 4. Cracked ice added to dough in mixer. 6. Cold air introduced into mixer during mixing process. . 6. Cooled agitators are used in mixers. . . .. . ' , . .. . ;. , , .. ` -} J MIXER DOAD CALCULATIONS Refrigeration is required to remove: excessIngredient, if anyjheat generated by the beating and miring of dough; excess heat mmixer body; heat of hydration of flour and water; and heat absorbed by mixer from, atmosphere during miring process. - : ' `! 1; i - Additional factors are-the design and speed of mixer* consistency* kind and mass of dough. - ' J Data Used in Calculations:; . 1 bbl. flour * 200 lb Heat of hydration a 6.6 Btu per lb of flour ; . .' . ' Specific heat of flour = 0.42 Btu per lb Water ib 65% of weight of flour ; Flour is 65% of batch . Sponge fa 60%'of batch ' . ' . - : .= . ' . '/ Total motor output is converted to heat in the mixer. In fermenting rooms reoent practice is to use direct radiation for heating, atomizing sprays for humidify, Ing, and gravity convection booling surfaces for temperature reduction and aehumidifying thereby eliminat ing objectionable air currents. ! . t 4 . : . . ; . . ill Proof box and bread cooler conditions vary slightly for dark.bread. Cakes are sterilised by ultra-violet rays before wrapping. ; ' , . '-ju-;: Process Tamp. F . R.H.% BANANAS , .. , : :- ' 68 ' 60 . 54 to 56 90 to 95 . 85 to 90 - 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 56 F is placed in a ripening room at 68F and 90 to 95 percent relative humidity until it begins to change color. The temperature is then lowered sharply to 60 F (or slightly less) dependent upon how quickly the fruit ia to be moved. ' '. Typical refrigeration load for ripening room per carlot, with an 85 F ambient temperature: Insulation & 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 possibly other gases necessary for ripening, ventilation during the early stages of ripening is undesirable. Cooling unit to be sized to provide a complete air change every 1} to 2 min. Information in Table 1 is drawn from many sources. See bibliography at end of chapter. Industrial Ail Conditioning 979 Table 1. Temperatures and Humidities Applicable to Industrial Air Conditioning--(Continued) BANANAS (Continued) . 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 = S,360Btu (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 ' Temp. F ' ' 1 R.H. % BREWING Storage: Hods.......................................... Grain...................................... Liquid veast............................... Lager.................................................... ........................ Ale.............................................. .................................................. Fermenting Cellar: Tawi- ___ Ale.......................... . Racking Cellar......... ....................................................... 1 If wooden tankage is used, otherwise humidity con trolled to prevent condensation on walls and ceiling. * 30 to 32 80 max.' 32 to 34 32 to 34 40 to 46 40 to 45 55 32 to 35 55 to 62 60 max.. 75 min.* . 75 min.* 75 min.* 75 min.* 75 ' Wort cooled to 47 F for lager, 54 to 59 F for ale* by evaporative cooling or use of double pipe or plate type coolers with counter flow of cooling^medium. Fermentation produces 250 Btu per lb of sugar fermented. Lager fermented five days at 55 to 50 F* ale at 68 ta.75 F, then cooled to storage temperature. . Bottled beer pasteurised by heating to 140 F in twenty minutes, 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 ammoniaor propylene-glycol and water solutions may be used as the cooling medium. . : . Temp. F 1 CANDY (CHOCOLATE) Candy centers for coating...................... Hand dipping room................................... Enrober room............................................... Enrobing Loading End............................................ Enrober...................................... . Stringing.................................................... Tunnel........................................................ Packing.......... .......................................... . Panned specialty room............................. . General candy storage.......... ................... Tempering room ** ventilation only 80 to 85 60 to 65 75 to 80 80 90 70 40 to 45 65 70 to 75 65 to 70 . R.H. 40 to 50 60 to 55 55 to 60 50 13 40 to 50 55 45 40 to 50 --___ >#uaaa .unci tuou me ceiBfRsrsture oi toeproauct leavingtne tunneL During the summer months the product ia usually held in the tempering room for 24 hours prior to ship ping. . -> Recovery of sugar fly in coating kettle rooms is accomplished with the use of cyclone type dust collecting devices. Supply air to coating kettles is maintained at 85 F dry-bulb and 61 F wet-bulb temperature. Bacteriological control is employed. Load calculations for hand dipping rooms are based on 1001b of 90 F chocolate per (worker) (hr). Specific heat of chocolate = 0.30 to 0.56 Btu per (lb) (F deg).' Latent beat of fusion = 34 to 40 Btu per (lb)(F deg). * Freezing point .' Sweet milk chocolate -- 86 F. ' Dark chocolate * 90 to 92 F. .. ' ' . ' ' Process Manufacturing................................... Mixing and cooling......................... Tunnel................................................ Packing............................................... Storage.......................................... . Tempering = (Ventilation only) Temp. F 1 R.H. % CANDY (HARD) 75 to 80 75 to 80 55 65 to 75 65 to 75 30 to 40 40 to 45 40 to 45 45 to 60 ,: ggO CHAPTER 45 . . 1954 Guide 1.Table Temperatures and Humidities Applicable to Industrial Air Conditioning--(Continued) .' CANDY (HARD) (Continued) . Hot rooms used in the drying of jellies and gums are maintained at 129 to .150 F. A purge system using 100 percent outside 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 hu midity of 45 to 50 percent. Uniform air distribution is essential. Standard starch drying equipment is employed. ; . . ... Filtration of air is required. `` . . . : Pbocess CHEWING .GUM Manufacturing.............................................................. ..................... Striping................................................... . .............. .......................... Breaking.. ......................................................................................... Temp.F..; 77 " '68 72 74 74 ' ^ R.H. % 33 63 53 47 ' 58 - ' - ' ' Pbocess ;' CERAMICS '' Temp. F ' V . . ...... R.H. . Refractory............................................................................................. ' 110 to 150 r.Molding room.. : -- --v ............ ......................... '-- 80 ' 60 to 80 - . 75 to 80 Decorating room,........... .......................................................... -- 75 to 80 - . 50 to 90 . 60 to 70 35 to 65 ' .. ; 48 48 Relative humidity has no effect on the manufacture of the products. - Temperature and humidity must-be controlled in the decorating shop in the whiteware 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. ' Pbocess CEREAL Packaging.............................................................................................. Temp. F 75-80 R.H. % ' .* 45-50 . Pbocess . Temp. F " , R.H.% ' < CITRUS FRUIT Lemons (storage)*................................................. ............................ 58 1 84 to 88 . * Prior to transcontinental shipment Careful consideration must be given to air volumes, air temperatures, humidity, ventilation and dis tribution. In regions where end rot is prevalent, it may be necessary to store grapefruit at temperatures of 32 to * 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 maintain 0.1% CO* content, (4) obtain uniform distribution, and (5) provide air washing or air filtration. '_ Load calculations include (1) transmission losses, (2) internal 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 ` _ .. Temp. 32 40 60 80 HEAT OF EVOLUTION IN Btu Peb (ton) (24 hb) Lemons Grapefruit 580 810 2070 6200 460 1070 2770 4180 Industrial Air Conditioning 981' Table 1. Temperatures and Humidities Applicable to Tndustrial Air , Conditioning--(Continued) tnuu I'nuii' (Continued) . Approximately 10 percent of the cooling load is considered, as latent heat ioacl In a conventional system the air required is one cfm per storage box or 650 cfm per carload, resulting in a small temperature nse in the supply air making possible the required high humidities. In a combination system the air required is one cfm per aq ft of floor area,or 300 cfm per carlot with-the addition of auxiliary humidifying nozzles to maintain the required high humidities. ..... . Installation of metal: ductsis required. Ductwork made of insulation board is sometimes preferred;; ' Pbocess TeMP.:F- ': .. . ,;}VR.H. %........... " DISTILLING ..{7. ,5.\, v", Storage: Grain................_______________ ................ " ` " 11 60 Liquid Yeast............................................................................... 32 to 34 General Manufacturing........ .........................;... :v...!!!!! 7! : ' 60 to 75 - ; ' ^ . 35 to .40 ; . - ' ''45to 60 . . r 60to'60'` - Mashing done at 150 to 155 F,-then-cooled to 64 to 68 F.'- * u,* -.; r Yeast culture fermented at 170 F, then oooled to 70 to 72 F. i; Yeast propagated at 150 to 154 F. ' : * . . : .. . r s ? Mash heated to 165 F and then cooled to 80 F, then pitched,with yeast and fermented at maximum tem perature Of oO Jt v* ** ` ' `` - * ` '1 4 ; i - *. Cooling for various distilling processes normally accomplished by use of river or well water dependina on temperatures and availability.- : 'i:i v ; ..........-=- r Low humidity and dust control important where grains are ground. Viscous Altera preferred as mold spores and bacteria hre trapped in the viscous film, preventing propaga- Process | Temp. F ELECTRICAL products Electronics and X-Ray: ..... . ... , . , Coil A transformer winding ......................................... Tabe assembly.............................................. .........7 Electrical Instruments: . " . ........ Manufacture and Laboratory./........................ . Thermostat assembly. & calibration ;.................... ......... ... ^umidistat assembly & calibration....................................! Small Mechanisms: Close tolerance assembly............................... ........................ o J"e*er assembly and test.................................................... Switchgear: . ' Fuse and cutout assembly.................. .. . .................................. Capacitor winding.................................................................... '.. Paper storage................................................................... . ; ,r Conductor wrapping with yarn:.............. ............................. '.. JUgntning arrestor-assembly........................................................... -thermal circuit breakers assembly and test........................... T'u wiieel generators: j^^nmner lapping................................................................ Processing selenium and copper oxide plates..................... control is essential in these processes ' .' * '- '7706 1` 1 ' 76 72 74 to 78 73 ` 73 73 75 68 76 70 74 | R.H.% 15 V 40 ' 50 to 55 50 to 55 - 50 to 55 40 to 45 60 to 63 50 50 50 65 to 70 20 to 40 .. *. 30 to 60.V\ 30 to 50 30 to 40 . Pbocess | Temp.F R.H.% FLOOR COVERING Linoleum: Printin^*^ oxidizing of linseed oil.............. Stoving process............................ * grains per pound abs: hum. 90 to 100 80 160 to 250 20 to 28 30 to 50 60 gr* Some operations are stabilized against possibility of mold growth. .: . teteof<fl^B.C?nj^L0^tempcr?tur6 humidity is required for mechanical oxidizing of linseed oil. The A* fiiW a temperature of cooling water in the jacket surrounding the tank must be controlled. ' filtration is recommended for the stoving process. 982 CHAPTER 45 > X954 Guide Table 1. Temperatures and Humidities Applicable to Industrial Aib . Conditioning--(Continued) ' Process . -. J FOUNDRIES Temp.* F ^ Hold making: Dcuch wor ... - ' ' .. * Winter design temp. 60 to 70 - ' 60 to 70 55 to 65 40 40 to 50 55 to 65 > 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. >. .. flooPr oaruerainagtrlooowmsspereeqdu. irSe htiweold-sinpgeeisdrepqouwireereddtorocoofnsvoenl rtailadtioartsio.n Design for minimum-of two cfm per sq from hot surfaces. Properintroduction ft of air will minimize preheat requirements. In shakeout room provide hoods with wet collector.dust removal system. Exhaust 400 to 500 cfm per sq ft grate area. Roof ventilators are generally not eSective. , . In cleaning room provide hoods for grinders and cleaning equipment with dry cyclones or bag type col lectors. ` ' Winter ventilation (preheated) is required to theextent of replacing exhausted air. Summer ventilation is usually supplemented by use of pedestal fans. .. ` Spot coolers are sometimes used in larger installations. . .. . R.H. % 110 . 18 to 20 40 to 50 55 to 65 Shock treatment, tor eradication oi any insect iuwmwuw, i^uum >UE vuw _________ 19-30 F for 3.to 4 days, then raising it to 60-70 F for 3 days, then lowering it once again to 18-20 degrees for 2 days and raising it to the storage temperature. ' . / 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 hu midity is lower than 55 percent. ' LEATHER After leather is moistened in preparation for rolling and stretching, it is placed in an atmosphere held at. room temperature with a relative humidity of 95 percent. ` . Leather is usually stored in warehouses without temperature and humidity control. However, it is necessary to keep humidity below 85 percent to avoid mildew. ' Air filtration is recommended for toggle machines. . Pbocess | Temp. F R.H. % - ^. LENSES (OPTICAL) . 75 * 80 _2_ 45 80 . The air must be free of dust and temperature held constant. . ^. To acquire desired cleanliness of nil a combination of impingement and electrostatic filters are 0300 Dust collectors are required for grinding operations. Industrial Air Conditioning 983 Table 1. Temperatures and Humidities Applicable to Industrial Air CoNDiTioNLNG-^(Continued) Rooms Temp. F LIBRARIES AND MUSEUMS R.H. % . 8 5 rod 9 0*pH de'mmidi&!n> used to eliminate SO*. Water treatment is essential to maintain between Reheat is usually, needed for refrigeration cycle due to the low sensible heat load. . In extremely cold weather a lower relative humidity is required to prevent condensation on walls. . . Positive high and low limit relative humidity controls are used. Do not locate water or steam piping ere leakage can cause damage. Check Figures for Cooling Estimates: Square feet floor area per person.............................. Watts per sq ft of floor area.............. .. Room sensible heat, Btu per (hr) (so ft) . Grand total heat. Btu ner (hr) (no ft).............. Sensible heat factor.......... ................. Cooling load per person, tons.......... ........................................... cfm per sa ft of floor area.......... '.. .................. Low 40 20 30 0.73 0.13 0.92 Medium High ' on 2' 0.23 1.00 0.40 MALTING (BREWING) Steeped 24 to 72 hr in 45 to 66 F water. Germinated six days at 55 to 75 F. Kilned at temperatures of 120 to 175 F. '' MALTING (DISTILLING) Germinated twenty days at 83 F. ', ` Germination produces total heat of 16,000 Btu/bushel at varying rate depending upon grain and Pbocess | Temp. F R.H. % , _ MATCHES Manufacture.............. . Paying...................................................................... storage.............. -- " `* 72 to 74 70 to 75 60 to 62 50 40 50 Water evaporated is 18 to 20 lb per million matches simultaneously with the setting of the glue. The match machine will turn out about 750,000 per hour. Process Temp. F MUSHROOMS Sweating-out period. Spawn added.............. Storage* period..... 120 to 140 60 to 75 48 to 60 32 to 35 nearly sat. moderate 80 to 85 As spawn starts to grow, it is necessary to abruptly cool the mushroom house by 15 deg in a 12 hr period fepprox.). Usually, this is the controlling factor in selection of refrigeration equipment, 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 7*scous film. Odorless oil should be used. Heat of emission is 4 Btu per (hr) (sq ft of growing surface)- 1984 CHAPTER 45 , ; t. - ' Table 1. Temperatures and Humidities Applicable to Industrial Air y-i---------------------- -- .TROCESB Temp. F paint application. , R.H. % . Lacquers: 70-90 180-300 60 Oil Paints . 60-90 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 Room ob Process R.H. % 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.......................................................... Colloids............ ..................................................................... Cough syrups...................................................................... Glandular products___.................................................... Ampule manufacturing!.................................................. Gelatin capsules.................................................................. Capsule storage.................................................................... Micro-analysis..................................................................... Biological manufacturing................................................ Liver extracts........................................................!--------- Serums.................................................................................... Animal rooms...................................................................... Small animal rooms. 70 to 8 75 to S 90 75 to 8 70 78 75 70 to 74 to 75 to 75 to 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, depending upon size of capsule. Moisture content should not exceed 0.25 gr per cu ft. Various kinds of gelatin require different temperatures. . Penicillin incubation process requires holding temperature within \ deg F, with temperatures and hu midity rigidly controlled during ail manufacturing phases. .(- Ampule filling requires a 20 percent relative humidity when especially fine powders are used. | . ' Uncoated tablet manufacturing requires accurate control cif temperature and relative humidity, since low relative humidity causes formation of a hard outer layer, and high relative humidity retards drying at theLpirvoepreerxrtaratec.ts require a 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 in troduced to Coating pans. ' Sterile conditions are essential in many pharmaceutical processes. Provide suitable air exhaust to re move surplus material from tablet compressing ^nchine. .'7; Air filtration is generally required, with positive air filiation in some areas. . . Animal Rooms in Pharmaceutical Laboratories Quantity Animal ' Weight Each 672 110 70 * 16 .5 ' White Mice Rats Rats Guinea Pigs Rabbits Cats Monkeys Dogs 21 g 200 g 400 g 410 g 3.0 kg ,3.0 kg Dogs are generally the worst offenders as far as odor generation is concerned. Decontamination of exhaust'air is recommended in populated areas. '' _ . ,ljfi For good air quality conditions the following space per animal and total air circulation (all outdoor of . - . Animaldecontaminated in recirculation} should be provided; Mice Rats Guinea Pigs Rabbits Hamsters Cats Dogs '' cu ft 3 4 6 10 8 35 150 cfm 0.5 0.75 1.0 1.9 1.5 10.0 28.0 Industrial Air Conditioning .985 Table 1. Temperatures'and Humidities Applicable-to Industrial'Air CoNDiTTOOTNG-^(Continued) . Process Temp. F . PHOTO' STUDIO R.H. % Dressing Room............................ ... Setting Room......................................... . Developing Room.......................;..................................................... 74 75-80 70 72 70-75 60- - 80 Heat liberated during printing, enlarging and;drying processes is removed through an independent ex haust system, which also serves the lamp houses and dryer'hoods.'? ii.i . . Dust control is essential, and absolute filtration is required in?some areas. -. . Process . . C./I TeMP.F-.; . r R.H. % . PHOTO MATERIAL Drying........................ ..................... ' Cutting & Packing........................ ............ ...............;................... Film Base & Paper Storage...................... '' ' Coated Paper & Film SLirntr* - Safety Base Film Storage........ - Nitrate Film Storage___ ........ 20-125 65-75 ~! 70-75 70-75 60-80 40-50 :. 40 80 40-450 40-65 im - Spray water must have algae inhibitor. Positive dust control must be maintained and absolute filtra tion is essential. '. , . In nitrate film area take proper precautions against fires. , . .. . - .. Recirculated air used for film.drying is passed through activated carbon filters. . . . .. Relative humidity for film storage should never exceed 60 percent with a minimum of 25 percent. Process Temp. F . . ' .. . plastics' . '...' .. . ' Manufacturing areas: - . Thermo setting moulding compounds\. .v....:___ Cellophane wrapping........... . .......... ' Absolute filtration is required in some areas. Collection and removal of dust and fumes is essential. 80 ? 75 to 80 ... - R.H. % 25 to 30 - . . f Process ' ' : - ' Temp. F R.H. % PLYWOOD ^.Pressing (resin).............................................. ;....................... Cold Pressing...... ...................................... ----------------------------------------------------------------------- ' POULTRY RAISING 90 Incubator. Brooder: 1st week........ 2nd week.. .. ^ttery room: Starting.......... Growing.'.;;; Egg storage .... 70-75 70-75 50-60 70 50-60 45-60 . 30-60 60 60 70-75 50-60 70-80 Maximum ventilation is required for laying quarters during the summer months, while an attempt is Blade 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. Process PRECISION MACHINING Spectrographic analysis..............- ................. Lear matching A special assembly room Gasket storage.................................................... Lement A glue storage;.................................. Precision parts ............................. 78-80 75-80 100 65 75 R.H. % 45-50 35-40 50 40 45-50 986 CHAPTER 45 1954 Guide Table 1. Temperatures and Humidities Applicable to Industrial Air Conditioning--(Continued) , ' Process . : | Temp. F R.H. % PRECISION MACHINING (Continued) Precision parts--honing................... ............................................... 75 68-75 72 76 78 75-80 45-50 45-50 42-50 45 .50 35-45 For general manufacturing and assembly .areas no attempt is made to.control conditions during hot - weather. An ample supply of outside air and air motion are relied upon to provide personal comfort. Low relative humidity is usually, maintained to prevent corrosion. . Temperature control within a narrow range is more important than temperature maintained. Dust control is required wherever polishing operations occur. Air distribution is important to maintain constant conditions throughout the area. PRINTING R.H. % Pressroom: Multicolor offset lithography............................. Other sheet fed printing..................................... Newspaper A other web printing................... Stock room: . Multicolor offset lithography............................. Other paper storage............. .......................... Binding, cutting, drying, folding and gluing Roll storage.................................................................. * 5 to 8% above pressroom same as pressroom 75-80 75-80 75-80 73-80 70-80 70-80 73-80 46-48 45-50 50-55 " 5-8% above pressroom b 45-50 50 Lithography requires constant humidity control of entire pressroom with paper conditioned 5 to 8 percent relative 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 prevents swelling of the rolls and slow ink drying. Temperature is not critical, but extremes should be avoided . 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 recovery 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. ' Summer--winter central systems are recommended for all except job shops where unitary equipment with coils and humidifiers may be used. Normal air cleaning is adequate. Air distribution must. prevent drafts on paper in storage or process. Gas flame dryers impose unusual loads* _. Air from press and storage rooms should not be recirculated through office areas. ' Process Temp. F refrigeration equipment 75 70 to 76 75 65 to 82 R.H.% i`" 40 30 to 45 30 to 50 47 Process | Temp. F | R.H. % RUBBER DIPPED GOODS ^ 90 80 75-80 60-75 73.4 25-30 25-30 40-50 50 Solvents used in manufacturing processes are usually explosive and toxic, requiring positive ventilation* Volume manufacturers usually install a solvent recovery system. ' Industrial Air Conditioning 987 Table 1. Temperatures and Humidities Applicable to Industrial Air . Conditioning--(Continued) Process TEXTILES Cotton: Opening-............................................................................... Picking.................................................... ................... ....................... Carding, Winter...... ................ ............. ........... ..................... .. Carding, Summer.................................................................... .. Carding, Summer........... ...................................................... .or Carding, Summer....... :........................... ;........... .. .or Drawing............................................. `..........1j.'.'. Roving....................................................................;.... Ring Spinning - Conventional.................................................. .............................. Long Draft.............. ............................. -..................................... Frame Spinning.............. ;.......... ...................................... ...... Spooling A Warping.................................................... ................ Weaving...................`.................:............;.... Cloth Room...........:............................................. ...................... ... Combing............................................................ ......................... ; Linen: Carding...................................................... ............................. Sp; ' eaving.. Woolens: Pickers.....___ Carding.............................. Spinning............................ Dressing............................ Weaving Light goods.................. Overcoating (32 os.). Drawing............................ Worsteds: Carding.......... Combing......................... Gffling............................. Top Storage.................. Drawing.......................... Cap Spinning.............. Spooling A Winding.. Weaving.................... Finishing...................... Silk: Preparatory........... Weaving.......................... Dressing.. . .................. Spinning......................... Throwing........................ Rayon: Spinning............................ Throwing........................................ Weaving - Regenerated.............................. Acetate......................................... Spun rayon................................ Picking........................ .................. Carding, roving, drawing........ Knitting Viscose or cuprsmmonium. Acetate............................. ... laboratory (ASTOf)................ Rayon synthetic fiber processing: Viscose . Separatory............... '.................. Weaving....................................... Lelanese.............................. '.............. Preparatory................................... Weaving.................... ..................... Nylon Piseparatory. Weaving........ 70-75 75 75-80 > - 83 . . . 87. 80 ` 80 ' 55-60 55 90 80 70 . 60 .: so : 80-85 . -80-85 , . 80-85 . . 78-80 78-80 75 70 55 55-60 65 70-85 65-70 50-65 75-80 . 75-80. ; 80 . 60 . 60 80 80-85 80-85 80-85 75-80 ., 60 65-70 50-60 60 80-85 80-85 75 60 60-65 60-60 80-85 80-85 80-85 70-85 80-85 80-85 75 80 75 : 65 65-70 65-70 75-80 65 50-55 65-70 55-70 60 80 60-65 80 60-70 80 60-65 80 65-70 80 60 80-90 ' 80 ` ; 50-60 55-60 ' 80 60 80 75^80 80-90 50-65 55-60 80 50-60 50-60 80-85 60-85 70 65 60 65 .80 ' 80 80 80 80 80 60 . 60 70 70-75 50-60 50-60 anrnn *iauve numiouy maintained in ring spinning depends on staple, twist and whether leather .?* are used for conveying long draft stock. Aprons readily absorb moisture causing cotton to stick when restive humidity is above 65 percent. dr5***k conventional`3 or 4 roll spinning, relative humidity-may be as high as 70 percent dependent upon twist and staple. . jJklative humidity carried in cotton weaving depends upon construction of the cloth. When automatic ines are to be.tended and the warps are heavily sized, it may be as high as 80 percent. conHif^71' woo^en spinning, the relative humidity maintained for mules is generally 55 percent, with sunn .i08 ?,ver frame spinning at 55 to 60 percent. Both types of spinning depend on the class of stock *'" also the regain in the roving. . 988 CHAPTER 45 1954 Guide Table 1. Temperatures and Humidities Applicable to Industrial Air Conditioning--(Concluded) TEXTILES (Continued) ' - Worsteds: 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 mid jackets. ' In churn room, where sodium cellulose is converted into cellulose xanthate, temperatures of 75 to 80 F are maintained 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 oontrol; For spinning operations it is desirable to limit the temperature 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.'. The storage room, where the material is held for later processing design conditions, are 85 F and 100 per cent relative humidity. .' . The material is washed, desulfurized, bleached and then washed again. It is then placed in a drier where controlled conditions of 100 deg and 65 percent relative humidity are required 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 maximum of 80 F. Relative humidity is held at 55 percent. - Process j Temp. F R.H. % TOBACCO r- ^ 70 to 75 90 75 to 85 74 to 76 75 78 75 55 to 65 85 to 88 70 to 75 .65 . 75 70 75 - ' ' In preparation for stripping, the tobacco undergoes a softening 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 aSeot the fin ished product. - 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 test laboratories. Moisture Content and Regain . In the manufacture or processing of hygroscopic materials such as tex tiles, paper, wood, leather, tobacco and foodstuffs, the temperature and relative humidity of the air have a marked influence upon the rate of pro duction and upon the weight, strength, appearance, and general quality, of the product. The moisture content of materials having a vegetable or animal origin, and to a lesser extent minerals in certain forms, comes to equilibrium with the moisture of the surrounding air. This moisture con tent 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 content be main tained at a level favorable to rapid and satisfactory manipulation, and to a' minimum loss of material through breakage. A uniform condition is desirable in order that high speed machinery may be adjusted permanently for the desired production with a minimum loss from delays, wastage of raw material, and defective product. Moisture content refers to free mois ture (as in a sponge) and to hygroscopic moisture (which varies with at- Industrial Air Conditioning 989 mospheric conditions). It is usually expressed as a percentage of the. total weight of material. Regain, is more specific and refers only to hy groscopic moisture. It is expressed as a percentage 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 per centage of the total weight (100.0 g) gives the moisture content of 7 per cent. The regain, which is expressed as a percentage of the bone-dry weight, is (7.0/93.0) 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 ob tained is used in the calculations to determine the regain. . Table 2 shows the regain or hygroscopic moisture content of several organic and inorganic materials when in equilibrium at a dry-bulb temper ature of 75 F and various 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 stationary. Changes in tem perature do, however, affect the rate of absorption or drying, although this property generally 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 heat equivalent 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 manufacture or processing of the mate rials, 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 Chapter 47). 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 conditioning may be combined in one process for the dual purpose of removing undesirable moisture, and accurately regulating the final moisture content. Frequently, condition ing or drying is made a continuous process in which the material is con veyed 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 reactions 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 itin? % 990 CHAPTER 45 1954 Guide orTable 2. Regain Hygroscopic Materials Moisture Content Expressed in Percent of Dry Weight of the Substance at Various Relative Humidities--Temperature, 75 F V -- CbUSh nemo* Description Relative Buuoitt--Per Cent . Auteorttt 10 20 30 40 50 60 70 80 90 Natural Textile Flbera Cotton Cotton Cotton Wool SUk linen ' Linen Jute Hemp Sea island--roving 2.5 3.7 4.6 54 6.6 7S 9.5 1-5 4.1 Hartshorn* American--doth . 2.6 3.7 4.4 5.2 5.9 64 &.1 0.0 144 Sddoedng . Absorbent . . 4.8 9.0 12.5 5.7 84 >04 12.8 144 254 Fuwa . . Australian meriuo^-skrin 4.7 7.0 8.9 104 12.8 14.9 11.2 19,9 23.4 Hartshorn* - Raw chevennes--skein 3.2 5.5 6.9 8.0 8.9 L0-2 U.9 44 184 Schloesing Table doth IS 2.9 3.6 44 5.1 6.1 7.0 8.4 I0L2 Atkinson Dry span--yarn 3.6 5.4 6.5 74 8.1 8.9 9.8 11.2 13.8 Sommer Average of several grades 3.1 5.2 6.9 8.5 10.2 12.2 14.4 17.1 20.2 Starch Manila and sisal--rope 2.7 4.7 6.0 7.2 8-5 9.9 11.6 13.6 15.7 Faws Rayons Viscose Nitrocefln-. lose Cupramonium Average skein Cellulose Acetate Fiber M. F. Newsprint Wood pulp--24% ash a M. P. Writing Wood pulp--3% ash Paper White Bond Com. Ledger Rag--1% sab 75% rag--1% 1> Kraft Wrapping Coniferous Leather Catgut Misc. Organic Materials Glue Rubber Wood Soap Sole oak--tanned . Racquet string* Hide Solid tires Timber (average) - White , Tobacco ' Cigarette White Bread Crackers Pood. stuffs Macaroni Flour Starch ' Gelatin Asbestos Fiber Finely divided Misc. , Inorganic Materials Silica Gel Domestic Coke Activated Ch&rcoa1 Steam activated Sulfuric Arid HtSDt 4.0 5.7 6.5 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 44 54 Robertson 2.1 3.2 4.0 4.7 5.3 6.1 7.2 8.7 10.6 U.S.B.ofSw 3.0 4.2 5.2 6.2 7.2 8.3 9.9 11 9 14.2 U.&B.nfSl 2.4 3.7 4.7 5.5 6.5 7.5 8.8 10.8 13.2 U.&B.oiS. 3.2 4.2 S.0 5.6 6.2 6.9 8.1 104 13.9 U.S.B.OSS. 3.2 4.6 5.7 6.6 7.6 8.9 10.5 126 144 U. S.B-oS. 5.0 8.5 11.2 13.6 16.0 184 20.6 24.0 294 Phelps 4.6 72 8.6 10.2 12.0 144 17.3 194 21.7 Fuwa 3.4 4.8 J.S 6.6 7.6 9.0 10.7 114 124 Fowa 0.11 0.21 0.32 0.44 0.54 0.66 0.76 048 G.99 Fuwa 30 4.4 5.9 7.6 94 114 14 0 174 22.0 Forest P. lab. 1.0 3.8 5.7 7.6 10.0 11.9 16.1 194 234 Fuwa 5.4 8.6 11.0 13-3 16.0 19.5 25.0 334 500 Ford 04 1.7 3.1 4.5 6.2 8.5 11.1 144 19.0 Atkinson 2.1 2.8 3.3 3.9 S.0 6.5 8.3 10.9 14.9 Atkinson S.l 7.4 88 tO-2 117 13.7 16.2 19.0 22.1 Atkinson 2.6 4.1 54 615 8.0 93 12.4 15.4 19.1 Bailey 2.2 3.8 SJ 6.4 7.4 84 9.2 10.6 12.7 .Atkinson 0.7 1.6 2.8 3.8 4.9 6.1 7.6 94 11.4 Atkinson 0.11 0.24 0.2C 0.33 0.41 0.51 0.62 0.12 .044 Fuwa 5.7 94 12.7 15.2 17.2 18.8 20.2 214 22.6 Fuwa 0.2<) 0.4t 0.6 0.8 1.0. 1.24 1.41 1.61 145 Setvig 7.1 14.3 22.8 26.2 28.3 29.2 30.0 31.1 32.7 Fuwa 33.0 41.0 47.5 52.5 57.0 61.5 67.0 734 824 Mason surface of the solution, and maintains a solution of known strength through out 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 hu midities have a retarding effect on the rate of oxidization at the surface, and Industrial Air Conditioning 991 allow the internal gases to escape freely as the chemical oxidizers ewe the1 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 for ob taining the best processing results. Control of Rate of Biochemical Reactions In the field of biochemical control, industrial air conditioning has been applied to many different and well-known products. All problems involv ing fermentation are classed under this heading. As biochemistry is a sub division 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 caTbon dioxide gases formed by the fermentation to pass through and produce a loaf of bread, when baked, of even, fine texture without large voids. The curing of fruits, such as bananas and lemons, also comes under this classification. Bananas require a cycle of temperatures and relative hu midities for ripening. The starches in the pulp of the fruit must be changed and the skin cured and colored, after which the fruit is cooled to maintain as low a rate of metabolism as possible. Ideal storage conditions range between 56 and 60 F, with about 85 percent relative humidity, and ventilation at the rate of three or four air changes per hour. The curing of lemons is an entirely different problem. Bananas are cured for a quick market, while lemons are held for a future market. The process, therefore, varies in the temperature used. Temperatures from 54 to 59 F have been found to be best suited for this process. A high rela tive humidity of 84 to 88 percent is necessary to hold shrinkage to a mini mum and, at the same time, develop the rind so it will be sufficiently tough to permit handling. ' . Tobacco from the field to the finished cigar, cigarette, plug or pipe tobacco, offers another interesting example of what may be done by indus trial air conditioning in the control of color, texture and flavor. In the processing of tobacoo, control of moisture regain, and of chemical and bio chemical reactions, is involved, and only through close atmospheric control can the best quality of leaf be developed. ' Control of Rate of Crystallization The rate of cooling of a saturated solution determines the size of the crystals formed. Both dry- and wet-bulb temperatures are of importance, a? the one controls the rate of cooling, while the other, through evaporahon, changes the density of the solution. In the coating pans for pills, gum, and nuts, a heavy sugar solution is ?dded to the tumbling mass. As the water evaporates, each separate piece is covered with crystals of sugar. A smooth, opaque coating is only accom plished by blowing into the kettle the proper amount of air at the right my- and wet-bulb temperatures. If the cooling and drying are too slow, me coating will be rough and semi-translucent, and the appearance un sightly; 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. 992 CHAPTER 45 1954 Guide Control of Temperature for Close Machining Tolerances , ! Where tolerances must be held within 2 or 3 ten-thousands 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. ' f ; Control of Dew-Point for Protection of Polished Surfaces - . In the manufacture of certain metal articles, the presence of finger ' prints, tarnish, or etching can not be tolerated in the finished article. \ If these articles are manufactured under. conditions of effective tempera tures 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. ,,v-. It is therefore important to maintain temperatures and relative humidi- .... ties (dew-point) low enough to prevent sweating of the hands. In addi- ) tion, the manufacture of polished surfaces usually requires a better-than- J- average job of air filtering to avoid abrasion of the surfaces. Control of Humidity for Reduction of Static Electricity The presence of static electricity is often detrimental to the satisfactory, and economical processing of many light materials, such as textile fibers,, t paper, etc. It is also extremely, dangerous where explosive atmospheres; or. materials are present. Fortunately, this hazard is- minimized by in-; . creasing the relative humidity to at least ;55 percent, if the material being,- . 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 ar relative humidity of 55 percent, or more. As some machines consume, r a great deal of power, which is converted directly into heat; the tempera-, , ture in the machine may be considerably higher than the temperature, adjacent to the machine where the relative humidity is normally measured., In such cases, the relative humidity in the machine will be appreciably lower than that elsewhere in the room, and it may therefore be neces-, sary to maintain a room relative humidity of 65 percent, or even more, to maintain the desired humidity. Control of. Conditions for Material Test Laboratories Laboratories having controlled conditions of temperature and humidity,1 are becoming more common, not only for the purposes of scientific re-' search, but also for routine testing and for quality production control. A- control of temperature and humidity within fairly 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 A.S.T.M. Standard Conditions of 50 percent relative hu-; midity and 23 C (73 4 F) temperature. . Industrial Air Conditioning 993 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. Because of the large number of motors and heat producing units usually found in an industrial application, it is particularly important that operating allowances, for the latent and sensible heat loads, be defi nitely ascertained and used in the calculations to determine the total design load. ' GENERAL REQUIREMENTS FOR HEALTH, SAFETY AND EFFICIENCY Control of Atmospheric Contaminants Safeguarding the health and maintaining the safety and efficiency of workers, require control of dusts, fumes, smokes, mists, fogs, vapors, and gases, and control of the . effective temperature,, which, includes tempera ture, humidity and motion of air about the worker. General ventilation may be relied upon in some cases to .control air contaminants. Chapter 11 gives .information on natural ventilation.. If mechanical ventilation is to be used, Chapter 33, Fans; Chapter 31; Air Distribution; Chapter 32, Air Duct Design; Chapter 34; Aar Cleaning; and Chapter 35, Spray Apparatus, furnish information on a broad range of industrial design conditions. - Specialists in the field of industrial hygiene should be consulted in case of doubt concerning the presence of airborne industrial hazards to health. Chapter 8, Air Contaminants; Chapter 6, Physiological Principles; and Chapter 7, Air Conditioning in the Prevention and Treatment of Disease, will be of help in determining the atmospheric conditions which should be maintained around the worker. Local codes, .ordinances,, or state labor laws must likewise be observed, particularly for ventilation requirements for hazardous trades. Comfortable conditions are desirable because they are likely to increase the efficiency of workers. For purposes of analysis, both sensible and latent heat should be included as contaminants of in dustrial atmospheres. A, recent small scale survey, has indicated that more than half of the air conditioning and ventilation installations in a typical industrial plant were concerned with removal of either sensible or latent heat as a source of air contamination. Contaminant Control Systems In general, systems for control of atmospheric contamination in industrial plants will be of three types: - 1. Local exhaust systems will be indicated where the contamination originates at concentrated areas and is characterized 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 46, 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 pointB dispersed generally throughout the area. .. 3. Combination of local exhaust and dilution methods is often economical, since well designed exhaust hoods or openings, removing 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. 994 CHAPTER 45 1954 Guide Design of Dilution Systems ' : '.1 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 contami nating load. This. will.often be'difficult', and may require construction of . pilot production models. Often, however, the required data will be avail able 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 engi neering judgment. However obtained, the determination of the nature and magnitude of the contaminating load is an indispensable step in the proper design of the corrective systeni.' Designs based on number of air changes per hour, or other rule-of-thumb methods, are hopelessly inade quate, and lead either to unsuccessful operation or to excessive andun- necessarily 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 contami nants, maximum allowable concentrations (MAC) of commonly encountered gases and vapors have been established, and these dataware tabulated in Chapter 8. From these data, and the previously established 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: ... ' . ... qQ _' (MAVC)X-1(0S` AC) . . (,) where Q = quantity of air circulated, cubic feet per minute. ' V = rate of generation of contaminant, cubic feet per minute. MAC = maximum allowable concentration, ppm by volume.; SAC = concentration in supply air, ppm by volume. ' The rate of- generation of the contaminating vapor will often be available as a iHeight or volume of liquid evaporated into the space per unit time. These may be converted to the units of Equation 1 by applying the principle that a pound-mol of a gas or vapor will occupy approximately 359 cu ft at standard pressure and tempera ture. Thus, . |V t I, 460 cfm (vapor) = --' X 359 X - ' 492 -f (2) 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 rone, resulting from concentrated sources of contamination, are intolerably higher than the average design concentration when using dilution methods. Data are available for calculations, but involve many assumptions regarding boundary condi tions, such as convection area and random air movement in the vicinity. 2. Dusts and Fumes. Maximum allowable concentration of various dusts, fumes and mists are also tabulated in Chapter 8. However, the dilution method as a means of treating particulate contaminating agents should be used with care, since the allowable air movement in spaces will ordinarily be lower than the capture velocity required for such particles. Exhausting at the source (see Chapter 46) will generally be the recommended treatment for these particulate contaminants. Industrial Air Conditioning 995' 3. Sensible Heal. Excessive sensible heat contamination is subject to treatment,' similar' to that for vapors,< by. the dilution method^ the difference being that the rate of generation of the contaminant must be expressed in units of energy rather than volume or weight, and-that the effect will: .be expressed as excessive tempera ture. In this case, the circulated air required will be: .. ' Q = (t.-Uxdxc ` (3) where ' ' . . . . ... _ . Q = quantity of air circulated, cubic feet per minute. H' = rate of generation of heat, Btu per minute: h = allowable temperature in the space, Fahrenheit. ta = temperature of supply air, Fahrenheit. ; d = density of air in pounds per cubic foot. c = specific heat of air. . : ' \ ' '. In some cases, such as ventilation systems not employing refrigeration, unusually large and uneconomical air quantities may, be required when the desired or tolerable.temperature (i.approaches too closely the temperature U of the dilution air. This condition may sometimes be corrected by a combination of treatment by dilution and central exhaust, large sources of heat load being eliminated by exhaust through hoods at the source. Heat Storage in Structure .. A special condition is sometimes encountered in large masonry struc tures when, due to the heat storage'capacity and time lag of the structure, a prolonged period of hot Weather may cause storage of such large quanti ties of heat in the structure that,they continue to.be a source of heat load after the outside weather has moderated. In general, the solution to ventilation problems by the simple dilution method is limited to cases where a practical and economical equilibrium may be established between the maximum rate of generation of the con taminant distribution and cost of the air required for its removal. " LOCAL RELIEF IN HOT AND HOT HUMID INDUSTRIAL ENVIRONMENTS, In many areas in industrial buildings, it is hot economically feasible to provide acceptable working conditions by the conventional means of venti lation and air conditioning. In such cases,1 local control of the environment (spot cooling) may be provided by means of shielding, air cooled booths, and spot cooling by means of air motion to provide a relatively cool area for the worker. These methods of local control may be used in conjunc tion with the natural or mechanical ventilation systems of the building to obtain the desired conditions for the worker, process or equipment. Spot cooling may be defined for the purposes of industrial environment control as heat relief of a local area within a larger space, independently of the general surroundings; a so-called oasis to provide conditions of relative comfort. . Environmental Considerations In the preliminary design for hot environments the following should be considered: . 1- Estimate the conditions of dry-bulb temperature, humidity, air motion, radiant .,22 996 CHAPTER 45 1954 Guide heat, effective temperature, and body heat balance. For buildings with low ceiling heights, the possibility that heated air may accumulate under the ceiling or that the ceiling may absorb heat and become a radiant heating panel should be explored. (See Chaps. 5 and 24.) Such radiant heat loads may represent other heat loads con sidered but not dissipated to the outside. In addition to the pertinent chapters in The Guide, the designer should refer to the articles by Small1, and Haines and Hatch* on the subject of heat relief in industry, in evaluating the above factors. !- 2. Consider the practicability of reducing the heat loads imposed on the area and worker by: a. Designing a building structure of adequate height, reducing the glass area exposed to sun radiation, and utilizing heat-absorbing glass to shield the high intensity radiant sources. . b. Changing the process in such manner as to provide lower operating tem peratures, thereby lowering the heat release to the area. . c. Providing air cooled booths, possibly in conjunction with remote operating controls and visual aid devices, so that the hot areas may be avoided except for short exposures. .. d. Insulating all surfaces above 125 F in temperature where these surfaces are extensive enough to add appreciably to the ambient air temperature or mean radiant temperature. ' ' e. Using canopy hoods for hot equipment or providing local hoods at flues and doors of furnaces and similar hot equipment to reduce the heat dissipated to the work area. .; f. Shielding hot equipment (often used in conjunction with hoods) so as to reduce sources of radiant heat. . ; 3. Give careful consideration to the type of clothing used by the workers.5 Light weight, open-weave fabrics in white, will frequently reduce the heat received by the worker to a small extent and will materially increase'the workers' ability to lose heat by convection and evaporation. Also, reflective clothing can be provided, as noted hereinafter under the heading Radiation SMelding. . .; 4. Heat removed from exchangers, motors, generators and similar equipment ciui be used to temper necessary make-up air or to neat the building in the winter. This,' heat can be discharged outdoors in warm weather. Physiological Considerations . In hot environments, the major physiological considerations are the de gree of activity of the occupants (this affects their metabolic rate or rate of; heat production), the length of the period of activity and occupancy, and-' the ambient environmental factors (dry-bulb temperature, mean radiant temperature, humidity and air motion) which control the dissipation and reception of heat by the occupants. The subjects of work activity, and the correlated effective temperature limitations are covered in detail in Chapter 6. While effective temperature is a good index for hot areas (when mean, radiant temperature effects are included), it must be realized that the allows, able effective temperature which can be considered for a particular area, must be dependent upon the degree of activity or work rate, and, conse-; quently, on the body heat balance. It is essential that body heat balances (metabolic rate plus heat received by the body, versus the heat dissipated, by the body) be maintained except for relatively short exposures to hot, environments. The subject is treated to some extent in Chap. 6, but Haines and Hatch2 have recently provided detailed data for estimating the maximum heat removal that can be expected for various environmental, conditions. These data and calculations will also provide a means of, estimating the maximum practical work rate for the area under considera tion, and will indicate the best means for providing relief for the worker, -ji Too little information is available on the effect of air motion (draft) on human comfort. An understanding of the subject is of great importance, in designing areas for local cooling. The comfort reaction to a draft is a function of (a) the physiological factors of work activity: position, age, sex, health and acclimatization; and (b) the environmental conditions of Industrial Air Conditioning 997 temperature, air movement (over the body), and humidity. In hot- at mospheres with high mean radiant temperatures and with high degrees of activity, a draft maybepleashnt. In cooler conditions with lesk active"work, a draft may be unpleasant. The body extremilies.are sensitive to draft and the head, neck, and shoulders have been found particularly sensitive if-subjected to continued or excessive air movement in conjunction with low humidity, sweating, and the impingement of low temperature air. The position of the worker is important. A person sitting, at rest, will produce less heat than a person standing, but because of the increased con vection and evaporation surface exposed, the latter can lose more;heat. Likewise, a person whose job requires him to stay at a-fixed point, cannot be comfortable under the same conditions of air movement as a person who is moving about and exposed intermittently to the same air movement. Yaglou4 among others, has pointed out that, minimum-body stress occurs with uniform cooling or heating over the body area. On the basis that the maximum work rate which can normally be maintained for an 8 hr day is 88 Btu per (sq ft) (hr) or 1700 Btu per'hr for a surface area of 19.5 sq ft, the following stress factors may be used as guides in determining the design of local relief areas in hot industries. . . ; ; 1. The effective temperature should be maintained below 85 F. (See Ref. 2 also.) 2. The relative humidity should not exceed 80 percent for normal temperatures nor should the wet bulb temperature exceed 83 F. (See Chap. 6, Fig. 9.) 3. The skin temperature should not exceed 95 F. , 4. The pulse rate should not exceed 125-beats per minute (from'an initial rate of 70 to 80). ; - ' 5. The rectal temperature should not exceed 100 F (from an initial level of 98 to 99 F). ' '' , These are neither rigid nor exact limitations but do provide guides for design purposes. Generally, the designer will do well to stay reasonably below these limits. If the limits of paragraphs'3,4, and 5 are not exceeded within the first two hours of work they probably wall not be exceeded during the work day provided there is no change in the rate of work or the en vironmental conditions. Radiation Shielding; ` ' : Shielding is an all-important method for reducing radiant heat exposures and the one technique that has been largely neglected in industry. A shield consists of a sheet of suitable material placed between a hot ob ject, such as a furnace, and its cooler surroundings. The closer it is placed to the hot object, the greater the effective coverage. Hot surfaces emit mfra-red waves which reach all objects, within visible range. Essential .to all shielding is the presence of an air,space between the hot object arid the shield to avoid conduction to the shield or a thermal short circuit. Radiation shields in the following forms are very effective: :. , b Sheets of reflective metal or insulating board, either semi-permanently at tached to the hot equipment (such as furnace buck stays) or arranged as semi-port able floor stands. . .? Aluminum foil faced cloth curtains which can be raised or lowered on spring rolls. , .- 3. Transparent shields, including heat absorbing tempered plate glass, reflective metal chain curtains and close mesh wire screens, These have lower efficiency than Paque shields described in preceding paragraphs 1 and 2. 4- Reflective garments, such as aprons, or in the form of a sandwich in cases of 998 CHAPTER 45 1954 Guide continuous front and back exposures. For continuous wear the apron or. sandwich width should be limited.to 14.to 18 in. to assure adequate continuous side.openings for air circulation and body .ventilation,, In addition gauntlets and face shields are .particularly applicable to operations such'as the:poufing and casting'of hot metid. Supply houses dealing in safety clothing for industry ofTer suitably lightweight flame proofed foil-faced cotton drill or denim oflexcellent reflectivity. . For repairs inside hot coke-ovens and industrial furnaces, a complete suit is avail able using forced ventilation frpm.a small blower or-a compressed air source*. .These suitB may be made of asbestos cloth, faced with a reflective metal in atomized 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 characteris tic. Hence a thin sheet is as effective as ,a' thick one. Tinplate, stainless Fid. Indirectional Outlets for Spot Cooling steel and ordinary flat or corrugated aluminum sheets are efficient and long-lived. Foil-faced plaster board, though less durable, obtains good reflectivity on one side.'' " ' ' :- ^ p Spot Cooling By Air Motion .V ... The previous paragraphs have described the steps which should be taken to reduce the heat load on the worker- or the work area. When these fad tors have been considered and the heat load has been minimized to a practi cal degree, the designer:may then resort to spot cooling by air motion to cool the worker himself. Such cooling may be provided by supplying air to the local areas or into suitable working enclosures or booths, or to venti lated coverall suits. The air supplied should be at such conditions temperature, relative humidity and air motion as to provide a cooling effect on the worker. .. ' These systems may also he used to provide make-up air for industrial exhaust systems, or to provide spot heating in the winter time. ' Such installations may be provided to improve the conditions around the Industrial Air Conditioning 999 worker continuously, or else to provide a relief area'where the worker will be in a cool zone intermittently. The designer, should keep this in mind in selecting the proper method of air cooling. '. Spot cooling may be provided by means of recirculated (man-coolers), direct outside, dehydrated, evaporatively cooled or mechanically cooled air, the solution depending upon the environmental'Conditions existing in the working area, and the economic factors. Generally, recirculated air will be effective only for areas of. moderate heat release. Other systems will be required for areas having high heat release. : A great variety of outlets may be used for spot cooling. Several dif-; ferent types are shown by Fig. 1. In addition, several manufacturers make remotely adjustable ceiling diffusers such'that the air'patterns may be altered from horizontal (parallel to the ceiling) to vertical, down. A number of manufacturers also make double deflection grilles that are good for this service. Such outlets1 can be provided in conjunction with an elbow type outlet and slip joint (see lower right diagram in Fig. 1) so as to provide directional discharge at any desired angle. The latter is very important to the worker because he may frequently, want the air discharging into the space but may not want it to blow ori him. ' , ' ' Perforated panels may also be used for the supply air. Such panels have low induction, characteristics and, used in conjunction with a booth could provide a low velocity blanket of air which should be effective for local heat relief, if supplied with cooled air. A booth would shield the worker from radiant heat and would permit effective cooling by means of the air supplied through the panel. , The outlet air velocities used for spot cooling systems may vary from 50 to 2000-fpm. The higher velocities are frequently used but should be used with caution as noted hereafter. The data in Chap. 31 Air Distribution, should be studied in determining the required outlet velocities correspond ing to the desired velocity at the worker or the operating station! The following items are particularly important in designing spot cooling installations: , 1. Where the personnel are engaged in work requiring little activity and where the exposure is continuous, the air velocity at the personnel should be low, approach ing the normal room velocities. The maximum velocity for such cases is sometimes given as 200 1pm. With greater worker activity and where the worker is in the air current intermittently, higher velocities may be used. See Chap. 6, Effective Tem perature Chart, Fig. 9. 2. Generally the temperature of the air impinging on the worker should exceed 3. When the temperature of the air impinging on the worker exceeds the skin tem perature the 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 remove the sweat, and thus fail to provide the maximum evaporative cooling for the existing: conditions. (See Ref. 5.) . . .. : 1- The outlets should be placed as close as practicable to the worker in order to take advantage of the lower discharge air temperature and the relatively larger core of air at the discharge air temperature. Installations in which the air is discharged from outlets 4 to 8 ft. from the worker are effective with small volumes of air, 200 to 1000 cfm. per outlet. At hot metal furnace working stations, 2000 to 3000 cfm. will be adequate. At greater distances more air is required due to the increased entrain ment of room air. However, the effect of the lower velocity air would be more toler able. 5. In selecting the outlets it should be kept in mind that large outlets have greater cooling effect because of the larger core of cool air. Slot outlets by comparison have bigh induction ratios, thus higher impinging temperature (at the worker). Per- 1000 CHAPTER 45 1954 Guide , forated panels have low. induction, ratios and thus will provide lower impingement temperatures.6 See Chap.31. . . ... : ': 8. Generally the outlets should have remote directional or volume control or,' preferably, both. The worker should be able in most cases to operate the outlet damper, vanes or louvers (or to turn .the .outlet) from the floor by some convenient means., . ' . ... , -The damper control should provide atleast 80 percent reduction in velocity. The workers may desire the full air velocity in hot weather, but may wish to reduce the velocity or to direct the air above the head zone in cold weather. 7. Generally the spot cooling air should.be directed to the front and to the torso of the worker. If possible the air should not be directed at the head, shoulders or the back of,the worker.. , .; , . . . .,8. When providing spot cooling with evaporatively cooled air, be sure that con ditions of high humidity will not exist and cause conditions detrimental to the com fort of the personnel or cause rusting or other difficulty with the equipment or proc ess. . ' ' . ' ' Generally the evaporatively cooled air should be limited to 20 to, 50 per cent of the total outside air circulated through the building. ,; Odors' ' There is little information available, either oh the rate of generation of common odors, or on the maximum concentration which would be tolerated by a majority of persons.' Thus a quantitative, specification covering systems for locker rooms and toilet .rooms, or other applications where odors constitute the contaminafit, is not now possible. Pending research in this important field, it is suggested that the data in Table 1, Chapter 6, showing the outside air supply required per person, at various socio economic levels, be used. , . REFERENCES , 1 Heat Relief in Industry j by'Bartlett R. Small (Iron and Steel Engineers Maga zine, April, 1952). ,, . . ' , * Industrial Heat Exposures--Evaluation and Control; by George F. Haines, Jr. and Theodore Hatch (Heating arid Ventilating, Nov. 1952, p. 94). 6 Physiology of Heat Regulation' and the Science of Clothing, by L. H. Newburgh (W. B. Saunders Co.). ., , 4 Thermal Standards in Industry--C. P. Yaglou, American Public Health Asso ciation Yearbook, 1949. . . . 6 Temperature and Human Life--C.-E. A. Winslow and L. P. Herrington, Prince-, ton University Press. . ' m i. 6 Private Discussion withG. L. Tuve and Alfred Koestel (Case Institute of Tech nology, May 31, 1952). : ' .. > . .u 1 When Is Complete Air Conditioning of the Modern Factory Advisable? by ri. A. Mosher (Heating Piping and Air Conditioning, June, 1945, p. 305 and July, 1945, p. 385). . BIBLIOGRAPHY . , . Processing . Air Conditioning, Design Conditions for Various Industries, by N. N. Wolpert (Heating and Ventilating, May 1949, p. 70; June 1949, p. 73; July 1949, p. 79;.Aug- 1949, p. 102). . . , : . .. T :, Air Conditioning Design Data for Commercial Applications, by N. N. Wolpert (Heating and Ventilating, Feb. 1950, p. 68). ASRE Data Book 1950 (American Society of Refrigerating Engineers). .; Refrigeration of Oranges in California, by H. M. Hendrikson and J. R. MacKiu, Refrigerating Engineering Application Data, No. 17-R (American Society of Refriger ating Engineers). Refrigeration of Lemons and Grapefruit, by H. M. Hendrikson and J. R. Maclun. Refrigerating Engineering Application Data No. ,18-R (American Society of K " frigerating Engineers). ' _ _ . '. . Air Conditioning in the Bakery, by W. L. Fleisher (A.S.H.V.E. Transaction , Vol. 37,1931, p. 141). Industrial Air Conditioning 1001 Air Condition the Bakery Throughout, by W. W. Reece (Heating, Piping and Air Conditioning, August, 1936, p. 419). ,, The Air Conditioning of Processes in the Bread Bakery, by H. R. Gable (A.S.H. v_E. Journal Section, Heating, Piping and Air Conditioning, October 1947, p. 107). Air Conditioning in Candy Manufacture, by H. G. Hoffmann (Section 39, Refriger ating Engineering Application Data, Refrigerating Engineering, April, 1947). Proper Air Conditions for the Manufacturing of Confections, by A. E. Stacey, Jr. (A.S.H.V.E. Journal Section, Heating, Piping and Air Conditioning, October 1937, p.640). _ .. Air Conditioning for Sausage Manufacturing Plants, by M. G. Harbula (A.S.H.V.E. Transactions, Vol. 28, 1922, p. 343). Relation of Air Conditions to Tobacco Curing, by J. Johnson and W. B. Ogden (Wisconsin Agricultural Research Bureau 110:1-48,1931).. Heating, Air Conditioning and Insulation for Penicillin Production, by J. C. Siegesmund (Heating, Piping and Air Conditioning, August, 1944, p. 475). Air Conditioning in Textile Mills, Research Department Technical Report, Textile Workers Union of America, C.I.O. Air Conditioning for Textile Plants Making and Using Synthetic Yarns, by L. L. Lewis (Rayon Textile Monthly, July, August, September, 1930). . Refrigeration for Textile Mill Air Conditioning, by P. L. Davidson (Heating and Ventilating, May, 1947, p. 57). ' Bureau of Standards Studies Determine Press Room Conditioning Requirements, by C. G. Weber (Heating, Piping and Air Conditioning, March, 1936, p. 137). Humidity in the Pressroom (Heating and Ventilating, May, 1932, p. 35). Dehumidifying with Gas in a Printing Plant (Heating and Ventilating, May, 1935, P- 31). . Air Conditioning the Newspaper Plant, by R. T. Williams (Heating and Ventilat ing, September, 1937, p. 63). Air Conditioning in the Paper Industry (Healing and Ventilating, October, 1935, p. 23). ; ' Air Conditioning Requirements of Multicolor Offset Printing, by C. G. Weber (Refrigerating Engineering, December, 1936, p. 6). Reactions of Lithographic Papers to Variations in Humidity and Temperature, by C. G. Weber and L. W. Snyder (U. S. Bureau of Standards Journal of Research, January,1934). The Treatment of Offset Papers for Optimum Register, by C. G. Weber and M. N. V. Geib (U. S. Bureau of Standards Journal of Research, February, 1936). . Silica Gel Air Conditioning System Serves Rotogravure Printing Plant, by H. E. Ryerson (Heating, Piping ana Air Conditioning, August, 1937, p. 497). Air Conditioning for Clothing Research Laboratory (Healing and Ventilating, July, 1943,p. 69). . Refrigeration Insures Quality of Clothing for the Army, by A. J. Mallinckrodt (Heating and Ventilating, March, 1944, p. 79). Controlled Air Supply for Supercharger, Carburetor and Engine Testing, by C. S. Leopold (Refrigerating Engineering, August, 1943, p. 85). CloseMachine Tolerances Possible Through Temperature Control, by R. P. Dewey (Heating and Ventilating, April, 1944, p. 60). Moisture Control by Liquid Absorption Offers a Useful Air Conditioning Tool, by F. M. Johnson (Heating, Piping and Air Conditioning, December, 1938, p. 782). Air Processing Needs of Plywood Plane Parts, by F. O. Jordan (Heating and Ven tilating, April, 1944, p. 67). The Engineering Control of Some' Solvent Hazards in War Industries, by S. C. Rothman (A.S.H.V.E. Transactions, Vol. 50,1944, p. 319). Air Conditioning as Applied in Theatres and Film Laboratories, by D. C. Lindsay (Jransachons Society of Motion Picture Engineers, April, 1927, Vol. XI, No. 30 p. Industrial Air Conditioning, by F. F. Stevenson (Heating, Piping and Air Condi tioning, May, 1948, p. 100; June, 1948, p. 94; and Jack F. Salsburg, July, 1948, p. 88, and Oct. 1948, p. 93). Industrial Air Conditioning, by Charles S. Cave (Industry and Power, July 1945, P- 67; Sept. 1945, p. 57). "J^ucing Heat Loads in Industrial Air Conditioning, by L. R. St. Onge (Refrigerat ing Engineering, January 1946, p. 35). Air, Light, and Sound Controlled in Western Electric's New Plant (Heating, Piping an`{Air Conditioning, Nov. 1948, p. 79). New IBM Plant Addition, Poughkeepsie, N. Y., by J. T. Browne (Heating, Piping and Air Conditioning, Jan. 1949, p. 111). 1002 CHAPTER 45 1954 Guide Photo Studios Need Conditioning for Both Processing and Comfort, by E. E. Herbacek (Heating, Piping and Air'Conditioning, June, 1949, p. 85); Foundry Ventilation, by Jim Black and Lester Avery (Heating, Piping and Air Conditioning, March, p. 71, April, p. 78, and May, p. 89,1947). . Dust Control for Foundries, by B. F. Postman (Heating and Ventilating, Dec 1948, p. 65; Jan. 1949, p. 78). .. Foundry Cuts Its Dust (Editorial, Heating and Ventilating, Feb. 1949, p. 85). Fog Removals in Industrial Plants, by R. C. Soronen (Heating, Piping and Air Conditioning, April, 1949, p. 72). Air Conditioning Crane Cabs, by R. D. Darrah (Refrigerating Engineering, May, 1949j p. 440). Air-Conditioned Crane Cabs, by B. R. Small {Industrial Hygiene Foundation, Pre ventive Engineering Series, Bulletin No. 4,1947). Health, Safety and Efficiency . Lectures, The Inservice Training Course in Environmental Controls for Industrial Processes, University of Michigan School of Public Health, 1946: Environmental Controls in Industrial Health, by R. R.-Sayers; Principles of Industrial Process Ventilation, by W. N. Witheridge; The Selection and Maintenance of Equipment for Process Control, by R. P..Warren; Environmental Control of Industrial Processes as Affected by Foundry Lay-out, by John Linabury; Foundry Ventilation, by J. M. Kane; Control of Welding Hazards, by W. C. L. Hemeon; Environmental Control of the Metal Cleaning Processes, by F. A. Patty; Painting, by T. F. Mooney; Health Hazards in the Electroplating Industry, by William Blum; Industrial Housekeeping and Sanitation, by John Soet. Air Sanitation and Industrial Ventilation, by W. N. Witheridge, Detroit, 1945. An Investigation of the Bacterial Contamination of the Air of Textile Mills with Special Reference to the Influence of Artificial Humidification, by W. F. Weils and E. C. Riley (The Journal of Industrial Hygiene and Toxicology, Vol. 19, Ho. 10, De cember, 1937). Industrial Cooling as a Production Aid, by J. Partington, Jr. (Heating and Ven tilating, April, 1944, p. 47). Industrial Exhaust Ventilation in Industrial Hygiene, by A. D. Brandt )A.S.H. V.E. Transactions, Vol. 50,1944, p. 331). Control of Industrial Atmospheres, by W. N. Witheridge (A.S.H.V.E. Transac tions, Vol. 51,1945, p. 227). . . Mine Ventilation and its Relation to Health and Safety, by D. Harrington (A.S.H.V.E. Transactions, Vol. 51,1945, p.243). i Ventilation Requirements for Industrial Solvents, by W. C. L. Hemeon (Healing and Ventilating, December, 1945, p. 95, January, p. 69, March, p.-82, and April, p. 79, 1946). .. . Guides for Industrial Ventilation, by Allen D. Brandt (Heating and Ventilating, March, 1946, p. 67). .. Industrial DuBt Explosions, by Hylton R. Brown (Heating and Ventilating, March; 1946, p. 73). .. . . . Supply Air in Plant Ventilation, by J. B. Skinner and William M. Pierce (Heating and Ventilating, May, 1946, p. 57). What Air Conditions Make for Comfort in Industry?, by H. A. Mosher (Healing; Piping, and Air Conditioning, April, 1946, p. 106). Air Conditioning Requirements for Workers in Factories, by H. A. Mosher (Heat ing. Piping and Air Conditioning, August, 1946, p. 82). Hot Weather LimitB Hard Work. (Brief summary of investigation done for Army . Quartermaster Corps, by Department of Physiology, Medical School, University of Indiana. Healing and Ventilating, August, 1947, p, 110). . a Methods Used in Determining the Health Hazaras Arising from the Inhalation of. Various Chemicals, by Francis F. Heyroth (A.S.H.V.E. Tbansactions, Vol. 53,1947, P-113). ' Air Recirculation from Exhaust Systems, by John M. Kane (Heating and Ventilat ing, April, 1947, p. 75). Should Air Be Recirculated from Industrial Exhaust Systems? by Allen D. Brandt (Heating, Piping and Air Conditioning, August, 1947, p. 69). Dehumidification Methods and Applications, by John Everetts, Jr. (A.S.H.V.E- Transactions, Vol. 53, 1947, p. 91). . Rating Dynamic Dehumidification Equipment, by E. R. Queer and E. R- McLaughlin (A.S.H.V.E. Transactions, Vol. 53,1947, p. 101). . -BSE CHAPTER 46 INDUSTRIAL EXHAUST SYSTEMS Elements of Exhaust Systems, Hoods or Enclosures, Capture Velocities, Air Volume, Duct System Design, Calculations, Construction of System, Materials, Details, Air Flow Producing Equipment, Air Cleaning Equipment, Make-Up Air, Maintenance of Performance, > Materials for Corrosion Resistance IN industrial plants, some type of exhaust system designed 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 con taminants, their particle sizes, maximum allowable concentrations, and upper and lower explosion limits are included in Chapter 8, Air Con taminants. Exhaust systems are extensively used for control of contaminants from; 1. Mechanical cutting and abrading operations including abrasive 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. More positive control, great reduction in exhaust volume handled, and reduced cost of air cleaning equipment will result. ELEMENTS OF, EXHAUST SYSTEMS An exhaust system will consist of (1) hoods or enclosures at all sources of air contamination, (2) branch and main ducts through which an air stream trans ports the contaminant to air cleaning device or to the outside atmosphere, (3) air moving equipment to produce required air flow into hoods or en closures, and (4) air cleaning equipment when required. See Chapter ,34 "art II, for discussion of types, applications, and principles of operation. HOODS OR ENCLOSURES1 ,oS Basically, hood design requires sufficient knowledge of a process or operabon so the most effective hood or enclosure can be installed to provide niiniHRim exhaust volumes for effective contaminant control. The more com plete the enclosure, the more economical and effective will be the installation. Many designers develop their hoods by mentally, enclosing the.operation completely and then providing access and working openings as indicated, r rom this complete enclosure concept are developed the familiar hood shapes hke booths, side or downdraft hoods (with or without side shields). AH 1003 1004 CHAPTER 46 1954 Guide openings are kept to a minimum size and are placed away from the natural path of the contaminant travel wherever possible. Inspection and main tenance openings are provided with doors whenever practicable. Capture Velocities and Air Volume Exhausted Only after the hood design has been determined can exhaust volume requirements be calculated. With enclosures, volumes are calculated from the known open area of the hood and ^he selection of the capture or indraft velocity sufficient to prevent outward escapement. Where enclosure of the process is impracticable, the air flow pattern in front of the hood must be such that selected capture velocities will be maintained in the area of generation, conveying the contaminant to the hood opening. . Usual capture velocities for typical operations are listed in Table 1 and Table 1. Minimum Alt Velocities Required at Point of Origin to. Capture Contaminant Effectively Condition op Generation , op Contaminant ' ' Minimum . Capture Velocity, FPM . Process Released without noticeable movement Released with low velocity . Active generation Released with great force 50-100 100-200 200-500 500-2000.. Evaporation of vapors, exhaust from pick- ling, washing, degreasing, plating, weld ing, etc. ' Paint spraying in booth; inspection, sort- ing, weighing, packaging, low speed Qess than 200 fpm) conveyor transfer points, blending, mixing, barrel filling. . Foundry shakeout, high speed (over 200 fpm) conveyor transfer points, crushers, screens. Grinding, tumbling mills, abrasive cleaning. refer in the case of remote hoods to the air movement required, at the zone of air contaminant generation. Required capture velocities for any opera tion will vary with the magnitude.of the air volume handled, with:uncon trolled air movement in the area, and oftentimes with the location ob the process or operation and size of the workroom. Larger remote hoods'ex hausting large air volumes will provide effective control at lowermaintained capture velocities than in the case of small remote hoods handling lower exhaust volumes. A hood at one end of a small narrow room with air supply at opposite end will provide control with lower capture velocities than that required from the same hood in a large room where no perceptible air flow will be obtained except in the immediate area of the hood. The method for determining, approximately, the quantity of air that must be exhausted from an unobstructed hood, without flanges,,to produce these capture velocities at the point of origin, is given in Equation 1 : Q = V(10X* + A) W where . . .n Q -- quantity of air exhausted, cubic feet per minute. .' V ~ air velocity in feet per minute at X distance in feet from the hood and on the centerline of the hood. ' X = distance in feet, along the hood centerline,'from the face of the hodd to the point where the air velocity is V feet per minute. ' ,;f A = area in square feet of the hood opening. .. Industrial- Exhaust Systems 1005 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 ve locity 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 studies2- 'l 12 have revealed variations in values of such velocity contours for long harrow 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 surround ing the hood opening usually will improve the air flow in front of the hood Fig. 1. Velocity Contours fob Rectangulab Opening with a Side Ratio of One-Half. Contours are Expressed as Percentages of the Velocity at the: Opening . and will reduce the air volume required to provide desired capture velocity by as much as 25 percent. ' 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 from falling granular material in large quantities tnrough considerable height, or from internal rotating parts like some types of crushers, knives, numerators. IT a b l e 2. A G u i d e t o V e n t i l a t i o n R a t e s f o b T y p ic a l n d u s t r i a l E q u ip m e n t ' State or Local Regulations Should be Consulted and Followed Where H igher V e n tila tio n Rates are Specified T a b l e 2. A G u id e t o V e n t il a t io n K a t e s f o r T y p ic a l n d u s t r ia l E q u ip m e n t (Continued)I State or L o c a l Regulations Should be Consulted and Followed Where H ig h e r V e n tila tio n Rates are Specified 1008 at>f Ha uEh a es O 3 - a4 s pf So og S5?< 2 h - 3 PH 0> R e f. 18, 21 fm o r 20-30i a ir heat removu1 CHAPTER 46 uo ooTs a 2w wc .jxa: V pd O H > J> ' M t. . O a 11 a | > 3 2 g& % -0 o.S > *2, ''0 a fl 861 -S& a J 00 -a Wis a-S tjjl si gS* .3 3a) CaU-2-TO3-T3t -'4C3f2l jsX S Js * S? c)SkOL W fe o 3: g.c-rs - o o e* o eo a>.g- ** e |,s 1-sf ? PCtf .. tf 1954 Guide f 16 *W s i =5 *-l . S*S . CoOs oCs et a-g-e .^y e-4 P9 0' ' ^ to d o * 1 pd Pd ' o oo 5 ?8 2 ?? Oo A oo o *CJ . >--a . s2 %o o ;a okO o ' nfitn go fs Exhaust pe sq jreen area ' od pe through 25-50 cf :fm ---vertical (d o w n w a rd ) w o rk ofm --horizontal w ork fpm . to 300 c fm per linear f t of hood w ith 200 fp m th r u feed and inspection open- a 00 cfm (fo r fu m e and gas rem oval) d io tly exhausted from projector housing CS <s ' 1 ^S3 a 3 5chS. "", " 5 *3 o a' ss o r Is - t. Q 1 Si Ss ho m "t1*I^L ' I d ' s .ri 1 ' * |s . 3 :-f i. i s& So a-a. -A -a5 " o -Si of. 8 to 1500 10 f t 1 Js t? dra tha ft n .iSlo .. "g --;c4 <0 a| ` - -200 fp m in u t n o t less ot velocities .ke-off every - a "i? .6 Il ; 2 o S' -sS Is ja -S sa s fS < 2ta oo.S 7 ' s;a o a ii- a 8as 1 1 go OO Z2 oo tS S - OewOOco .oco ie owo oo ^ ta |S BctXI <8 E n c lo s u re , F u lly enolose Hood i 1 Enclosure | Local hood Hood E p o lo s u re Side hood 1- o & >, H fl 5 3 * fl *o <3 & s s 0& "o aa A is a <5 s| a . 'a a .2a*fc. Is ? d'n.P Is -1 a a 04 5 aa _i 1 S e 1 Sjls.s u 5 -- v. *t 1 -aam . 0s curing hoods Foundry Rock drilling D r y d rillin g (re ireens V ibrating F lat deck hakeouts ' F o u n d ry ? ti 2 I fl a 1 T Si fol '3 s. -ao JS CQ 3 E n c lo s u re h< . .3 o' Hfl ' oa u V o fl tc .a "V3 *3S X.- M J2 3 fl 3 aw CQ | R e f. 32, 33 T- '. W ; /.Mtt.ui' <fiC-y. fcua Industrial-Exhaust Systems 1,{* .-a i UO T0O9 5 S*. "1 o aan . S a? a2fl tMo . fl SH Pd e f*a- x ves S3 2b 'K < gH j> 500-2000 500-2000 500-2000 Ref. 13 Use higher ventilationf t booths 4 sq or less 5' ` ( ' 3|sl -^E 1. ,, "1^8 ^1111 1 --ol gS5 fcl< 1& STs ,i3T : -gg'SS llll o 3 s ' o 3 - :" ! 8 1 a 2 o N 2000 2000 c3 t R e f.18 3000 3000 3500 . b< fc Q. *s > sg 'I o<S. fltf*,l fS*f3l} o CQ 2O..5 a Ed >. -ooo W 'o a. A ir Flow fl fl .2.2 If 09 03 . ooi3< SC5 JS^ fl . OooO 3fl . *fl t0a*0O .saagos, oo <owi<io *o j2'!5 !! Efie a&| f fT .fl.fl.fl III S s 1115 g -<oa^^s flr g. Sxj a 1 S| .2-0S=-5*2 ' 3 B*3.-a fl S*o^ s `5 ofs'3' i s^`*f 1 II "Jjr -'-gi " 3 . gll s^g&. STilrf - :4*Zf3l&ol.~3S3.2Ofl ..^XJ*nw ..f5sl ef fe *3 -$ Ba a 2O*9 8Bp !=> SB : I"8 - orefl lip Ss BE s-l? ^c.SgS , ^.S'-csS ' .2 S T .-.'iotSSS _ 3 i ' g>> .2o o 0 Is si x-S . 9 s M X3 :fl a *fl 1 *3 1 Off} ' J S| gg IJ5J1 3 fl g o ,|il|l.. 1 si's* =iIaS& . oT.SS94 *g-^ooto -. gS fQSN2s S3 *3 >o 3 2 49 * -fl . CO : &s is I ' , . . . , ...8 o2 fHf?ll o g> i 5; 8 S ' ta . cu 3' jm*2o a 6S 1. ', 8 ao a? 33 O 5is * aw t CO fl -a3,2 H - |8` ' is 'H III I3! !!* mB 3 11 "g cs* |PiS*l 4?l3 * i.ST3.S.g -Isj *f oo .iiSgpJa pi, (! it i !7 i ' I :: i : i : if ! i .Id 1010 CHAPTER 46 . 2. Induced air flow caused by the thermal or stack effect from sources of ex treme heat. : _ . 3. Exhaust volumes insufficient to dilute mixtures of combustible vapor and ' air to less than 20 percent of the lower explosive limit of the combustible. 4. Room air currents caused by cross drafts, spot cooling, motion of machinery or operators. 5. Local or State regulations may specify larger exhaust volumes for specific opera tions. Exhaust volume requirements for many specific operations have been listed in Tables 2, 3, 4, and 5. ;- Table 3.. Exhaust Requirements*7 fob Grinding, Polishing, Buffing, Scratch Brushing Abrasive Cut-Off Wheels, Grinding and Polishing Belts . (Air Volume: 4500 fpm in all branches.) (g in. water suction at average hood) Grinding or Cut-Opp Wheels Butting, Polishing, and Scratch Brushing In. -9 10-16 17-19 20-24 25-30 31-36 Max. Branch Width*, In. Diam, In. li 2 3 4 5 .6 3 4 41 5 6 7 .225 390 500 610 .830 1200 Wheel Diam, Max. Branch In. Width*, In. Diam, In. -9 10-16 17-19 20-24 25-30 2 31 3 44 45 5 51 6 61 300 500 610 740 1040 - . :: - Horizontal Single Spindle Disc Grinders Horizontal . Double Spindle Disc Grinders Vertical Single Spindle Dffldi Grinders . Wheel Diam, In. Diam, In. Wheel Branch Diam, In. Diam, In. CFM Wheel Branch . CFM ^ Diam, In., Diam, In. -12 3 225 * -19 1-5 610 -20 1-44 500 ~ 13-19 20-30 4 5 390 610 20-25 26-30 1-6 1-7 880 1200 21-30 31-53 2-4 2-6 780. 1760 - 31-36 6 880 31-53 2-6 1760 54-72 2-8 3120 If 64-72 4-8 6240 .- 3 Grinding or Polishing Beltb: To 3 in. wide--3 in. branch, add 1 in. to branch diameter for each 2 in. or fraction increase in belt width over 3 in. - . .' ' - * Increase branch diameter 0.3 in., but not less than l in., for each 1 in. increase in width over dimension noted. -- Duct System Design :. !? The duct system will consist of branch ducts connected to a main du<&, which will convey the air from the hoods to the exhaust fan and the-air, cleaning equipment, if used. Round ducts should be used wherever pos sible. Their gage size and construction differ from air supply practice due to the rougher usage encountered, and in the case of. dusts, to the abrasive effect. . (See later section on Exhaust System Design and Construction Fea tures.) Usual conveying velocities are shown in Table 6. Where solid con taminants are handled, recommended velocities must be maintained through: _ out the system to prevent material from settling in the ducts and obstructing the air flow. For conveying of solid particles, velocities shown in Table Industrial Exhaust Systems 1011 include a reasonable factor of safety, and design velocities may therefore be adjusted to use commercial pipe sizes which are available generally in 3-in. diameter steps through 6-in. diameter and 1-in. steps through 16-in; diameter or larger with 2-in. diameter steps for large diameters. For con taminants that are not solids, conveying velocities are based on a balance between the higher resistance and lower first cost of smaller diameter ducts against higher first cost and lower resistance of larger diameter ducts. Table 4. Ventilation Rates for Open Surface Tanks Minimum Ventilation Rate CFM Per Sq Ft Hood Opening Minimum Ventilation Rate CFM Per Sq Ft Tank Area Lateral Exhaust (Note 1) Enclosing Hood Canopy Hood One ' Two Open Open Side Sides Three Open Sides Four Open Sides W/L 0-0.24 AB W/L 0.25-0.49 AB W/L ' 0.50-1.0 AB Plating Chromium (Chromic Acid Mist)..:................ :.................... 75 Arsenic (Arsine)___ .................... 65 Hydrogen Cyanide...................... Cadmium........................................ Qodizing........:................... ............. 75 75 75 Metal Cleaning (Pickling) Cold Acid.............................................. 65 Hot Acid.......................................... 75 Nitric and Sulphuric Acid. .. 75 Nitric and Hydrofluoric Acid.. Metal Cleaning (Degreasing) 75 Trichloroethylene......................... 75 ..Ethylene Dichloride................... 75 , Carbon Tetrachloride................. 75 Metal Cleaning (Caustic or Elec trolytic) Not Boiling... 65 Boiling.............................................. 75 Bnght Dip (Nitric Add)_______ stripping 75 Concentrated NitricAcid.......... 75 Cone.. Nitric and Sulphuric Acid............................. . 75 - Salt Baths (Molten Salt)............... 50 Salt .Solution (Parkerue,'Bond- erize, etc.) Not Boiling........... 90 .............................. ............... M Wlter Gf vent- desired) Not Boiling.................................... Boiling.............. 75 75 50 100 90 100 100 100 90: 100 100 100 100 100 100 90 100 100 100 75 90 100 75 100 125 175 125 175 150 200 175 225 100 150 90 130 110 150 130 170 125 175 125 175 150 200 175 225 125 175 125 175 150 200 .175 225 125 175 125 175 150 200 175 225 100 150 90 130 110 150 130 170 125 175 125 176 150 200 176 225 125 175 125 175 150 200 175 225 125 175 125 175 150 200 175 225 125 175 125 175 150 200 175 225 125 175 125 175 150 200 175 225 125 175 125 175 150 200 175 225 100 125 125 150 175 175 125 175 75 125 90 130 110 150 130 170 125 175 150 200 175 225 125 175 150 200 175 225 125 175 150 200 175 225 125 175 150 200 175 225 60 90 75 100 90 110 100 150 90 130 110 150 130 170 125 175 125 175 150 200 175 225 75 125 60 90 75 100 90 no 125 175 125 175 150 200 175 225 A *?th kd along one aide or two parallel sides when one hood is against a **11 or a baffle running length of tank and as high as tank is wide; also to tanka with exhaust manifold Mong center line with ^ beooming tank width in W/L Ratio. Column B refers to free standing tank with hood along one side or two parallel aides. duels connecting two or more branches are sized by the same proedure The main should be designed for the total exhaust volume to be uandled through all branch ducts. Where exhaust systems handling solids are to provide for a substantial jncrease of future capacity, required conveying velocities can be maintained intn Frvi<fing Open end stub branches in main through which air will be admitted system until future connection is made. The volume admitted into the main 1012 CHAPTER 46 1954 Guide Table 5- Exhaust .Requirements fob Woodworking Operations"- {Air Velocity: 4000 fpm in all branches unless noted otherwise) ; Self Feed Table Rip Saw ... ,, Us 1-5 in. branch at bottom pulley; 1-4 in. branch at saw bead. Large Self Feed Rip Saws Other Than Table Saws Use 1-6 in. branch at bottom; 1-6 in branch at top. to2oTm. use 1-4 in. branch; over 20 in. use 1-4)4 in. branch. Circular Saws - ' Up to 12 in. diam....................................................................................................................... Dado head saws.............. .................................... -- .............. ^ Ve^it^lation^te'depcnda on effectiveness of hood and maximum number and diameter of saws. Disc Sanders Up to 12 in. diam... v. 12 in. to 18 in. diam'. .. 18 in. to 26 in. diam... 26 in. to 32 in. diam... 32 in. to 38 in. diam.. 38 in. to 48 in. diam.,. . .................................. J~4 in. branch ................................ 1-4)4 in. branch .................................... 1-5 in. branch -- %.......................... 2-4 in. branch 1-4 in. branch and 1-5 in. branch 1-5 in. branch and 2-4 in. branch M' Uulptiptloe3D1 riunm. wSidaned.e..r.s....(..o..v..e...r...t.h...e...t.a:b...l.e...).. ............... ................. ;......................................... 5 in. branch (see note) 31 in. to 49 in. wide......... ...............................................;................. ............................................ 6 in. branch (see note) 49 in. to 67 in. wide......... ............................................................... *.............................................. 7 in. branch (see note). Over 67 in. wide.......................................................... .................................................................. 8 in. branch (see note) Note: One branch of size indicatedrequired for each drum. Fewer branch pipes may be used as long as total branch pipe cross sectional area is not reduced. Some manufacturers use 1 extra branch of equal site on feed side. 1-4 in. branch may be required for exhausting bed rubber cushions or mechanically operated brush. Single Drum and Spindle Type Sanders Up to 50 sq in. sanding surface........... . 50 to 200 sq in. sanding surface............ 200 to 400 sq in. sanding surface.......... 400 to 700 sq in. sanding surface. .......... 700 to 1400 sq in. sanding surface........... 1400 to 2400 sq in. sanding surface........... 1-3 in. branch 1-4 in. branch 1-5 in. branch 1-6 in. branch 1-7 in. branch 1-8 in. branch Horizontal Belt Sander or Edge Sander (see note) . Drive Pulley Up to 6 in. wide.................... ............................................................................. .......... 1-4)4 in. branch .......... 1-6 in. branch Idler Pulley 1-4 in. branch 1-4 in. branch 1-4 in. branch Note: Where^more than one belt is used, the pipe sizes specified shall be required for common hood is used for more than one belt, a single pipe of an area not less than the sum of the areas the pipes specified may be used. ` ... .# ,i , . ,, _. Where belt is reversible, pipe at idler pulley shall be the sue specified for the drive pulley. . Vertical Belt Sandera (rear belt and both pulleys enclosed) 6 fn to 9 h. wide.............................. !........... 11 ! . ...................................................... * S! . ........................................ ...................... 8 in. branch on bottm? in. branch on bottom Band Saws and Resaws Bottom 3 in. 4in. Over to to 5 4 in. wide.......................................................................................... 5 in. wide................................................t-- ............... ............* in. wide.............. 1............. ................. ............................... ................ .............. .............. ........... 1-6 in. branch 1-7 in. branch 1-8 in. branch Jointers p p Top 1-4 in. branch 1-4 in. branch 1-5 in. branch 1-5 in..branch 1-5 in. branch 1-4 in.-branch 1-5 in. branch 1-6 in. branch 1-7 in. branco Industrial Exhaust Systems : 1013 Table 5. Exhaost Requirements for Woodworking Operations (Concluded) . (Air Velocity: 4000 fpm in all branches unless noted otherwise) dingie Planers or Suriaceia Up to 20 in. max. working width .. 20 in. to 26 in. max, working width. 26 in. to 32 in. max. working width. 32 in. to 38 in. max. working width. Over 38 in. max. working width . ... 1-6 in. branch 1-7 in. branch 1-8 in. .branoh 1-t9 in. branch 1-10 in. branch Double Planers or Surfacers Up to 20 in. max. working width... 20 in. to 26 in. max. working width. 26 in. to 32 in. max. working width. 32 in. to 38 in, max. working width. Over 38 in. max. working width .... ./fas, 1-10 in. branch U & Moulders, Matchers, Sixers (see Note) ' Matcher head Top Up to 4 in.............................................................................. . 2-4 in. branch 1-5 in. branch 4 to 8 in..................................................................................... 2-5)4 in. branch 1-6 in. branch 6 to 8 in.............................................'....................................... 2-6 jn. branch 1-7 in. branch 8 to 18 in............................................ ....................................... 2-6 in. branch 1-8 in. branch Note: Where profiler is used, provide additional pipe not lessthanthatspecifiedfortop head. Bottom ' 1-6 in. branch 1-6 in. branch 1-6 in. branch 1-8 in. branch Wood Shapers 1-4)4 to 10 in. branch for each spindle according to size and character of work. Tenoner '- . For cutoff saws: Dp to 12 in. diam............................................................................................. .............. _ Over 12 m. diam.................................. ........................................................................... Use 1-5 in. branch minimunm-tfonr Meai>chh. t/omp eand bottom teno--n, -c--o--p--e----a---n-jd dad1o'h.e'aVd.............. 14 in. branch 1-5 in. branch ' Automatic Lathes - Use 1-3 in. to 1-10 in. branch according to work length. Hogs . . Air volume based on 50 cult per lb of refuse conveyed. Use 4500 fpm minimum conveying velocity. Floor Sweeps . Use 6 in. branch for fine dust to 8 in. branch for coarse material. Mouth at floor, 10 X 4 in. to 12 X 5 in. . ." Note: Area of floor sweep pipe need not be included in computing main pipe area. Miscellaneous Equipment '` Pulley pockets and chain mortises-3 in. branch; dovetail and lock comer machines, dowel machines, duplex molding sanders, forming lathes, panel raisers (each head), ploughs, rail shears, routers, sash stickers (each head) 4 in. branch; pulley atiles-5 in. branch; glue jointer-6 in. branch. can be adjusted to required airflow rate, c/m, by use of a blast gate or orifice plate in such stub branch. 2. Arranging system layout so future points can be picked up by a separate main which will run directly to the fan or air cleaning equipment inlet. CALCULATION OF SYSTEM PRESSURE LOSS The pressure loss of the system includes entrance loss37 as air is accelerated through the hood to a branch duct connection, resistance loss of ducts,38 elbows, and junctions, and acceleration or deceleration losses from velocity changes within the system. Chapter 32 includes data on duct resistance and on resistance of elbows, and provides sample calculations. In exhaust sys tems, either the equal friction method (illustrated in Chapter 32) or the use of blast gates in the branches to equalize pressure loss of all runs is em ployed.8- "13 18 . Data on losses for hood entrance and branch entry, transitions 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 velocity pressure in the branch and the hood entrance loss. 1014 CHAPTER 46 . 1954. Guid.e Table 6. Approximate Conveying Velocities Material Conveyed _ Design Velocity FPM Large particles, heavy loads, moist materials................................ 2,000 3,000 3.500 3,500-4,500 . 4.500 and over TAPER R, (REGAIN) L, (LOSS) ANGLE, FRACTION OF FRACTION OF ccgrEs VP DIFFERENCE VP DEFERENCE 3.3 3 <0 ts 20 25 30 OVER 30 0.76 a72 0.56 0.42 a28 0.13 0.00 aoo 0.22 0.26 0.44 0.56 ` 0.72 a 67 1.00 1.00 DECELERATION LOSS A REGAIN TAPER L, (LOSS) ANGLE. FRACTION Of DECREES VP DOTERENCE 5 0.05 to 0.06 IS 0.06 20 0.10 25 an 30 o.u AS 0.20 <0 as ACCELERATION LOSS 'Lta, BRANCH ENTRY LOSS K" WEATHER HOOD LOSS Fig. 2. Exhaust System Design Data1* Tapered hood data from Reference 37. Weather hood data from Reference 38 Industrial Exhaust Systems 1015 EXHAUST SYSTEM CONSTRUCTION SPECIFICATIONS AND DESIGN DETAILS13 Correct design and competent installation of sheet steel ducts and hoods are necessary for the proper functioning of any exhaust system. The follow ing specifications are mainly those recommended in the manual Industrial Ventilation.13 General Requirements All exhaust systems shall be constructed with the materials recommended here with and shall be installed in a permanent and workmanlike manner. The interior of all duets shall be smooth and free from obstructions; with joints either welded, flanged, or soldered air-tight. . Materials a. Ducts shall be constructed of black iron welded or of galvanised sheet steel riveted and soldered unless the presence of corrosive gases, vapors and mists makes 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. b. For average exhaust systems on non-corrosive applications the metal thickness in the following table shall be supplied. Diaueteb or Stbaioht Doers (Inches) Up to 8......... Over 8 to 18. Over 18 to 30 Over 30.......... U. S. Standard Gauge fob Steel Duct Class I 24 22 20 18 Class 11 22 20 18 16 Class HI 20 18 16 14 Class t. Includes ducts non-abrasive applications such as for paint spray, wood working, pharmaceutical, and food products. Class II. Includes ducts for non-abrasive material in high concentration (low pressure pneumatic conveying); moderately abrasive material; and highly abrasive materials in light concentrations. Typical examples are chemicals and wood dust; exhaust of foundry shakeouts and sand handling systems, grain dusts; coal crushing and screening; exhaust of grit blast cabinets; and grinding, buffing and polishing. Class III. Includes ducts for conveying all highly abrasive materials in moderate to heavy concentrations and moderately abrasive materials in heavy concentrations as in: low pressure conveying of tobacco; and exhaust systems from abrasive cleaning operations, rock and ore screening and crushing, dryers and kilns, and flyash from boiler stacks. ' Where aluminum duct is indicated, the following equivalent B & S gage thickness of sheets should be used: Steel--U. S. Standard Gage Aluminum--B & S Gage 26 24 22 24 22 20 20 18 18 16 c. Elbows and angles shall be a minimum of two gages heavier than straight lengths of equal diameter. d. Hoods shall be a minimum of two gages heavier than straight section of con necting branches. e. Where flexible piping is necessary, a non collapsible type of flexible piping shall he used and its length shall be kept at a minimum. Construction - a. Longitudinal joints of ducts shall be lapped, and riveted or spot-welded on $'in. centers, maximum. ' b. Girth joints of ducts unless flanged or butt welded shall be made with lap in direction of air flow with not less than 1-in. lap. 1016 CHAPTER 46 1954 Guide' c. Elbows and angles should have an inside or throat radius of two pipe diameters whenever possible, but the radius shall never be less than one pipe diameter. Large radii are recommended 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. Angles shall be pieced proportionately. .. .. d. Hoods must be free of sharp edges or burrs and shall be reinforced to provide necessary stiffness. .. . e. Provide dead end caps within 6 in. from last branch of all mains and sub-mains. f. Provide cleanouts every 10 ft and near each elbow, angle, or duct junction in horizontal sections. ` g. Support ducts sufficiently to prevent placing of any load on connecting equip ment and to carry weight of system if plugged with material. Use maximum sup porting interval 12 ft for 8 in.or smaller ducts and 20 ft for larger ducts. .. h. Provide 6 in. minimum clearance between ducts and ceiling, wall, or floor; i. 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 construc tion whose diameter equals the longest side. j. All branches shall enter the main at the large end of the transition at an angle not to exceed 45 deg (30 deg is recommended). Connect branches only to top or sides of main, with no two branches entering diametrically opposite. System Details a. Connect duct to fan inlet with split sleeve drawband one pipe diameter long but not less than 5 in. b. Transitions in mains and sub-mains are to be tapered; taper 5-in. long for each 1-in. change in diameter is recommended. c. Place blast gates for adjustment of system near connection of branch to main. Provide means for locking gates after adjustments have been made. d. Fire dampers, explosion vents, etc., should be installed in accordance with NFPA Codes or local fire ordinances. Deviation From Specifications Where State or local laws conflict with the specifications given, the more stringent regulation shall be followed. Any other deviation must be approved before instal lation. AIR FLOW PRODUCING EQUIPMENT The principal types of air moving equipment are centrifugal fans, axial flow fans, and venturi ejectors. Chapter 33 includes information on fan types, arrangements, and application. Gravity stacks have application for some systems handling higher air temperatures or steam where no air cleaning equipment is installed. 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 clean air side. Ih paddle wheel or modified paddle wheel designs are heavily constructed an have few blades to make them more suitable if wear, corrosion, or ac cumulations are a factor. The higher efficiency backward curved blade designs find application where relatively clean, non-corrosive air is hancneuForward curved blade designs have limited application due to the nurnoet shape, and metal thickness 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 involved, where added pressure losses from air cleaning equipment TMPr0T . ments are anticipated, or where the fan may be used at some later date 1 another application. The axial flow fan is used for systems having low pressure losses. Pro Industrial Exhaust Systems 1017 peller or disc designs develop pressures under 1 in., the vane-axial designs develop higher pressures but seldom are used where pressures exceed 3 The venturi ejector39 is an inefficient method of air movement, but has the advantage of causing air flow without the exhaust air passing through the air flow producing equipment. It minimizes the explosion or corrosion potentialities in certain types of system. Fans, motors, and drives should be located so that safe and easy access for periodic inspection, servicing, and maintenance is possible. AIR CLEANING EQUIPMENT As discussed in detail in Chapter 34, air cleaning equipment should be considered in all systems to prevent property damage, neighborhood pollution, re-entry to the working space; to salvage usable material, reduce fire and explosion hazards or to make possible some recirculation of air to the working spaces. The present growing emphasis on air pollution control makes it desirable to remove all contaminants to the greatest practical de gree based on reasonable 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 per formance bf 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 low pressure systems of roof ventilators or general ventilation systems; downflow through heater vent stacks preventing exhaust of flue gases to the outside. Systems for conditioning make-up air do not necessarily increase heating requirements for the space, as cold air due to infiltration from the outside must be heated somehow to maintain comfortable temperatures in the area. The cost will depend 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 con trol 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 in clude 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 . system was installed. Testing and recording of such data for each new rnstallation are of the utmost importance. While hood suction readings have rightfully been discarded as .a means of Measuring air flow, they do offer a quick and accurate method of measuring dative air flow. If the hood suction is known while an exhaust system is t?nct,l0ning properly, its continued" effectiveness can be assured so long as he hood suction is not reduced from its original value. Unless the hood design is altered or there are accumulations in the hood or ranch pipe between hood and point of hood suction reading, the air volume aT b l e 7. R e s is t a n c e t o C o r b o s io n o f M a t e r ia l s U s e d f o b H o o p s a n d D u c t s " T a b l e 8 . R e s is t a n c e t o C o r b o s io n o f M a t e r ia l s U s e d f o r E x h a u s t F a n s *0 1E 1 E 1 E E 1018 CHAPTER 46 1954 Guide SLNiOf DUSTH BUM ajij xv-io aaurexiA HBIfaSlWHSlWWWHHWWiaHW ._____________ _____________ JtNIYJ 3A-IX . ,| kissh ai-niRiA <E ft 5 ft ^03 - CG-._ CD W gffDX ho asvog 1N3R30 soxsassy urea'll xsvo anog ho `aasvg aoo4ia3i] ao aoOAiiTX daaKog ' XNJVJ qoom asbothj da^jvx aOO^ SO 'IV.L3ft NO aaxaax asaaoO'S . MOHJ ATVQ NO .* 00Z-081 `xH S0V3g HO ATVD NOHJ NO XNIVX 3 8 ~fMaoot 4 TV3S0HO5J s VNflg axvig aNHax. aNaHjoa^j aoo^ aassaag aaaang 'ivnOiTM aaaaog <jhvjj KONUC0TV onini'i ava'] 13NOW Taaxg aaa'iNivi^ ft 3 CD . ,ft ft B H 0< W CD CD ft ^ ftft ft CD ft CO ft ft 09 CD CD CO ft ft a CD ft CD ft CD ft ft ft ft CD CD _ CD ftftcDftcoHftWWWftWft ft H 1. | CD ft .00 | CD ft ft ft ft ft CD CD )1 ft ft CD ft ft | S to 1 ft ft s 1 ft co ft ft ft CD ft 1 CD ft ft1 " a ft ft ft n. I ft ft ft ' Qj ft ft ft ft CO ' 0* CD ft co cD w AS , so ~c> 8 S ?. o o " '3 ? 2J o o aaft -I ,c521? #* 5 S-. a Z CD .1a3 5gJuS r S||| 5 ?V .M! 30- -5 *' 'j^o ft #" C i 2 |2 Si g f S'**3 c Sg ew <*? Sin? .9 Jj B 3 ** ; *3g C .2 SS I1 13 Hi aj o 0 NOHJ aaZINVA'IVO aixiNiOO^ aag Iy ^ S W W W Id CQ tfl DQ s ol BgS- > t~o|4 E? IcsS !!f!l 3 .5 ft 3 O A II sg e -S o 3 o2 WA ao < ^o ff 6 c o. 6 S 3 ' O~ v 3,, ,-11 a 61 1a33 : *&* .2 t* I i e o il-3 so - -n <aWOgo u3^,; 2 u ss Sj>? ZS** OJSJ b3 q& b . j -o 3 y 5 55 5. "-r8f *3 S '3 `o -- : S . tt sC QstSiB.,_ D31S 2*S a &| .* eS * s aS E .t2a -ga Is *___IM___a<S HO a 11* J (lll sl . N: 2 ft ` T"3 go*5 ' 3iC 5O -v.! 5I !* T. 3 *1 Industrial Exhaust Systems \' I aZNOHg OK>V 1 Oh - 918ISXV aoOM aaBOTHg ft. . '. ft otiohox' ft ft . HOaaaAg ft ft ft ft ` 3N3Hd03^ ft ft ft ft Hasaag uog . ONINPJ aaaang aavg onuvoq aa-svg Nieag onoNang CD ' ft. ' ft ft ft ft CD CD ft CD X3VHHBy xoh . ft ft ' . ; ft. ft ft to ft CD iNivg avag aag ft ft iNJVg Nisag TANIjV ft XNtvg nvaasy O. P-1 CD ft ft drag ft ft CD CD . CL ft CO . esvag ft ft ft NOHJ XBVQ laaxg aaziNYA'irQ m w co co aft naKuwny CD CD CD ft CO ft aaaxg ftftft 09 ' CD CD ft ft ftftCDftftftftftft :a g ;&? ^s | .2 8> `g a S 111 a j< a g* 8a a as . s 3-2 2^ a 1019 Ig <a 5 BS h"SEoEoS.2 On e^ O- .S s 32 1 1 2 Q .S .2 ft Ml .Oa3 *C 8 5- -3 - Ooo Q a w S -g `3 3 'ff t TI W CD Uh ft O 1020 CHAPTER 46 1954 Guide/ 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. Difficulty from plugging may be encountered where heavy dust loads or moist air is encountered. In any case, the hood suction method of checking -can more readily be delegated to an assistant having no technical training, whereas the Pitot tube method requires care in reading velocity pressures in an exact position with the tube paralleling the flow of air. U-gages have been standard plant equipment long enough to eliminate any feeling of un certainty in their use. ; Since pressure readings vary as the square of the velocity or volume of flow, a slight change in flow is magnified by a comparison of gage readings. Nor mally, a reduction of volume or velocity of 10 to 15 percent will not be suf ficient 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 reduced 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 accumu lations 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 clean-out doors, broken joints, holes worn in duct (most frequently in elbows), or poor connection to the exhauster inlet. 5. Losses in suction due to additional exhaust points added to the system or 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 In many cases, exhaust systems including hoods, ducts, air flow producing equipment, and air cleaning equipment will require protective coatinpsjf 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, (b) protection against product contami nation, and (c) explosion hazards. Of the above groups, construction for corrosion protection is the most dif ficult due to the complex factors that influence rate of corrosion. It b seldom possible to predict the concentration, composition, and dry- and dew-point temperatures that will exist in actual operations. A guide for selecting corrosive resistant materials based on a survey of actual expe riences has been reproduced in Tables 7 and 8.40 REFERENCES The material in this chapter is based largely on the recommendations of the American Conferaiu o/*" ernmentai Industrial Hygienists as published in the Industrial Ventilation Manual, 1952 Edition. 1 The Determination and Control of Industrial Dust, by J. J. Bloomfield and J. M. DallaValle (Build1 tl7, U. S. Public Health Service, 1936). * Exhaust Hoods, by J. M. DallaValle (Industrial Press, New York, 1952). * Design of Exhaust Hoods for Dust Control Systems, by T. Hatch (Journal of Industrial Hvt&* fl Toxicology, Vol. 18, 1936. p. 595). ' Industrial Exhaust Systems 1021 < Air Dilution in Industrial Ventilation, by W. C. L. Hemeon (Healing and Ventilating, February-1941). * Practical Application of Industrial Exhaust Ventilation for the Control of Occupation Exposures, by 3. F. Postman (American Journal of Public Health, Vol. 30, 1940, p. 149). ' * Principles ofIndustrial Process VeniHaiicn, fey W. N. Witheridge (University of Michigan Inservice Train ing Course, October 1945). 11ndustrial Dusts, by Philip Drinker and Theodore Hatch (McGraw-Hill Book Co., New York, 1936) * Design of Industrial Exhaust Systems, by J. L. Alden (Industrial Press, New York, 1948). * Ventilation, by W. N. Witheridge (Industrial Hygiene and Toxicology, Vol. I, Chap. 10, Edited by F. A. Pstty. Interscience Publishers, New York, 1948). ' "Transport Velocities for Industrial Dusts, by A. C. Stern et al (American Industrial Hygiene Associa tion Quarterly, December 1948). 11 Industrial Health Engineering, by A. D. Brandt (John Wiley and Sons, New York, 1947). Velocity Characteristics of Narrow Exhaust Slots, by Leslie Silverman (Journal of Industrial Hygiene and Toxicology, November 1942, p. 267). u Industrial Ventilation Manual, (American Conference of Governmental Industrial Hygienists, 1952 Edition). . . J* Code ofRecommended Good Practice for Metal Cleaning; Sanitation (American Foundrymen's Association). 14 A Study of Asbestosia in the Asbestos Texile Industry, by W. C. Dressen et al ((7. S. Public Health Ser vice, Bulletin 241, 1938). u A Study of Dust Control Methods in an Asbestos Fabricating Plant, by R. T. Page and J. J. Bloom field (U. S. Public Health Reports, Reprint No. 1883, Nov. 26, 1937). . 11 Rules Relating to the Control of Silica Dust in Stone Crushing Operations (New York State Depart ment of Labor, Industrial Code Rule No. 34, July, 1942). . w Design of Exhaust Systems, by J. M. Kane (Heating and Ventilating, November 1945, p. 68). u Foundry Ventilation, by J. M. Kane (The Foundry, February and March, 1946). w Pottery Dusts: Their Collection and Removal, by W. M. Oddie (Pottery Gazette, Vol. 53, 1928, p. 1280). * Scrapbook of Exhaust Hoods, by J. M. Kane (Heating and Ventilating. Portable Grinding--July 1950; rinding. Polishing, Buffing--August 1950; Foundry Shakeout--November 1950; Melting Furnaces--Feb* ruary 1951; Pottery--March 1951; Mixers--April 1951; and Woodworking--June 1951). 8 ^teign of Exhaust Ventilation for Solid Material Handling, by R. T. Pring et al (Industrial and Bngineertnp Chemistry, November 1949). Hartzdl Blowers.' Engineering Data & Installation (Hartsell Propeller Fan Company, Bulletin 1001). The Application of Local Exhaust Ventilation to Electric Melting Furances, by J. M. Kane (Transac`ns, American Foundrymen's Association, Vol. 52, 1945, p. 1351). f *`'on*ro^ ? Silicosis Hazard in the Hard Rock Industries. II. An Investigation of the Kelley Dust Trap 07 8e ^^h Pneumatic Rock Drills of the Jackhammer Type, by T. Hatch et al (Journal of Industrial Ha- February 1932. p. 69). Modified Design of Hay Dust Trap, by P. S, Hay (Journal of Industrial Hygiene, January 1930, p. 28). American Standard for Grinding, Polishing and Buffing Equipment Sanitatioi (American Standards A*soc\atum, Z 43-1941). * Swin* Prams Grinder Dust Control, by J. M. Kane (The Foundry, August 1944). What We Make (B. F. Sfcurtevant Co., Catalog No. 500). , _yenrilation of Motion Picture Booths, by P. Drinker and J. R. Snell (Journal of Industrial Hygiene W To2Kolm, April 1938, p. 321). j - J^ow Justify an Industrial Air Conditioning Investment, by P. J. Maischall (Heating, Piping and Conditioning, February 1952, p. 71). 1.7-,. Exhaust Hoods for Quartz-Fusing Operations, by E. C. Riley et al (Heating and Yen- {Uahn9. April 1940, p. 23). 1022 CHAPTER 46 1954 Guide A Study of Quartz-Fusing Operations with Reference to Measurement and Control of Silica Fume* by E. C. Riley and J. M. DaUaVaile (U. S. Public Health Reports, Vol. 54, 1939, p. 532). ' ^Ventilation of Open Tanks, by A. C. Stern (American Industrial Hygiene Association, Industrial By. ffiene Quarterly, Sept. 1950). - American Standard for Safety in Electric and Gas Welding and-Cutting Operations (American Stand ards Association, Z 49.1). ". w Rules Relating to the Removal of Dust, Gases, and Fumes (Veto York State Department'of Labor, In dustrial Code Rule No. H, Jan. 1931). .. - . ' - tt Energy Losses at Suction Hoods, by A- D. Brandt and R. J. Steffy (A.S.H.V.E. Transactions, VoL ..-52, 1946, p. 205). ' ` ** Resistance Test on Pipe, by A. Nutting {Mechanical Engineering, May 1933). Design of Injector for Low Pressure Air Flow, by G. E. McElroy (.U. S. Bureau 0} Mines, Technical Pa per 678). .. American Standard Safety Code for Ventilation and Operation of Open Surface Tanks (American Stand ards Association, Z 9.1*1951), .- CHAPTER 47 INDUSTRIAL DRYING SYSTEMS Drying Terminology, Mechanism of Drying, Internal and External Conditions, Periods of Drying, Approximate Equations for Estimating Drying Time, Equi librium Moisture Content, Applications of Hygrometry to Drying, Dryer Calculations, Drying Methods and Equipment; Radiant, Conduction and Convection Drying; Solution of Drying Problem THE term drying, in a broad sense, encompasses the removal of water, and occasionally other liquids, from gases, liquids, or solids. How ever, the common usage of the word confines the meaning principally to the removal of water or solvent from solids by thermal means. Dehumidi fication is the term that is commonly assigned to the drying of gases. This is usually accomplished by condensation or adsorption by various drying agents, and is treated in Chapter 38. Distillation, and more particularly fractional distillation, is associated with the drying of liquids. It is usually more economical to employ, whenever possible, mechanical means of separating as much water as is practicable from the solid mate rials before undertaking drying or dehydration steps. These mechanical methods such as 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. DRYING TERMINOLOGY1 The generally accepted definitions of terms used in drying technology follow; 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 bound 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 sur f es" ,oun<i moisture can 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 interstices and over the sur face of a solid. It is caused by liquid-solid molecular attraction. Commercial dry basis expresses the moisture content of a product as pounds of water per pound of solid as it leaves the dryer, .e., per pound of commercially dry BOlld. the constant-rate period is that drying period during which the rate of water re moval per unit of drying surface is constant. The critical moisture content is that obtaining when the constant-rate period ends and the falling-rate period begins. riry 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 junount of moisture loss is obtained simply by subtracting the moisture contents Deore and after drying. (See definition of Wet Basis.) Dryer efficiency is that fraction of the total heat, supplied by fuel, used to evaporate f ater- Overall efficiency is sometimes used to distinguish overall system efficiency m the efficiency of the drying space or evaporative efficiency. %Alrium moisture content is that to which a given material can be dried under Pacific conditions of air temperature and humidity. ^Evaporative efficiency compares the amount of evaporation actually obtained in a ^TyT with that which would obtain by saturation of the air. rfalling-rate period is that drying period during which the instantaneous drying continually decreases. 1023 1024 CHAPTER 47 1954 Guide Fiber saturation point is the moisture content of cellular materials (wood, etc.) at which the cell walls are completely saturated while the cavities are liquid-free. It may be defined as the equilibrium moisture content as the humidity of the sur rounding atmosphere approaches saturation. Free moisture content is that liquid content which is removable at a.given tempera ture and humidity. Free moisture may include both bound and unbound moisture. The funicular state is that condition in drying a porous body when capillarysuction causes air to be sucked into the pores. -' Humidity denotes the amount of water vapor actually present in a gas, and is generally expressed as weight of vapor per unit weight of any gas. A hygroscopic material is one that may contain bound moisture. Initial moisture distribution refers to the moisture distribution throughout a solid' when drying begins. ' Internal diffusion. Diffusion is a single-phase phenomenon; internal diffusion must therefore occur as solid through solid, liquid through liquid, or gas through gas. Internal diffusion occurs when the moving phase obeys the fundamental laws of diffusion. The moisture content of a solid is usually expressed as moisture quantity per unit weight of volume of the dry or wet solid. A weight (dry or wet) basis is preferred. 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. A non-hygroscopic material is one that can contain no bound moisture. . Pendular state is that state of a liquid in a porous solid when a continuous film of liquid no longer exists around and between discrete particles and, therefore, flow by capillarity cannot occur. This state succeeds the funicular state. Unaccomplished moisture change refers to the ratio of the free moisture present at any time to that initially present. Unbound moisture in a hygroscopic material is that moisture in excess of the equi* librium moisture content corresponding to saturation humidity. All water in * non-hygroscopic material is unbound water. , 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 moisture is constant for all moisture contents. Fig. 1 shows the relationship between the dry- and wet-weight bases, and indicates that when the wet-weight basis is used to express moisture content, a 2 or 3 percent change at high moisture content (above 70 percent) actually represents a 15 to 20 percent change in evaporative load. An evaporative increase of this amount might well increase the load above the capacity of a dryer. MECHANISM OF DRYING1 When a solid dries, two fundamental processes are involved: (1) the transfer of heat to evaporate the liquid, and (2) the transfer of mass as vapor and internal liquid. These two processes 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 trans fer may occur by convection, conduction, or radiation, or by any com bination of these mechanisms. The various types of industrial dry may be shown to differ fundamentally with respect to the method usea 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 ex ception is drying with high frequency electrical currents where heat generated within the solid, producing a higher temperature at the inteno than at the surface, and consequently, causing heat to flow from lnsiu the solid to the outer surfaces. Mass transfer in drying occurs as liquid or vapor flow, or both, withm Industrial Drying Systems 1025 the solid, and as vapor flow from the external wet surfaces. The nature of liquid concentration gradients in solids during drying depends on the mechanism 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 vs. External Conditions A study of how a solid dries may be based on the internal mechanism of liquid flow, or bn the effect of the external conditions of temperature, humidity, air flow, state of subdivision, etc., on the drying rate of the solid. The former procedure involves a fundamental study of the liquid flow conditions within a solid during drying. The latter procedure, al though less fundamental, is more generally used because the effects'are utr 60 fa 540 Z 30 2. 0 50 too 150 - 200 250 300 350 400 4SO 500 550 600 . - ' PERCENT MOISTURE - DRV BASIS - Pig. 1. Relation between Wet-Weight and Dry-Weight Bases easier to establish and the results have greater .immediate application in dryer design and operation. . Internal Mechanism of Liquid Flow. Internal liquid flow may occur y several mechanisms, depending on the structure of the solid. Several mechanisms of flow are as follows: , 1. Diffusion in continuous, homogeneous solids. i' papillary flow in granular and porous solids. 4 fi cause<l by shrinkage and pressure gradients. Plow caused by a vaporization-condensation sequence, o. How caused by gravity. ' How caused by an electrical potential, electro-osmosis. flow caused by temperature gradients, thermal diffusion. a2^10,'^1 more than one of these mechanisms ol flow may be effective d rine "m?> only one predominates as a rule at a given time in a solid differ^ , r^m\ However, a different mechanism may predominate at a estahfk jme *n. cycle. The mechanism of moisture flow is usually ished experimentally from a study of moisture gradients. drvir'/mia^ Variables. The principal external variables involved in any 0f I, ^ Problem are: temperature, humidity, air flow, state of subdivision contrftua :' aSt^atin of the solid, method of supporting the solid, and the nepp between hot surfaces and wet solid. All these variables do not isanly occur simultaneously in one-problem. 1026 , CHAPTER 47 1954 Guide Periods of Drying1 A typical drying time curve for a wet solid is shown in Fig. 2. This curve is a plot of the moisture content at any time in a solid undergoing drying. It is the usual method of presenting experimental drying data. Although Fig. 2 shows that the moisture content is subject to a continuous variation with time, a more precise illustration of the nature of this varia tion can be obtained by differentiating the curve and plotting the drying rate (pounds of water per hour per pound of dry material) against the moisture content (pounds of water per pound of dry material) as shown in Fig. 3, or plotting the rate of drying against time as shown in Fig. 4. These rate curves show that the drying process is not a smooth, continuous one in which a single mechanism controls throughout. The rate curve in Fig. 4 has the advantage of showing how long each drying period predom inates. Section AB on each curve represents a constant-rate period. In Fig- % it is shown by a straight line of constant slope dW/dB, which becomes a horizontal line on the rate curves in Figs. 3 and 4. Mofstur* Content (On/ Oersfs) d8Fio. 3. Rate or Drying -to- vs. Moisture Content W' Industrial Drying Systems 1027 The curved portion of Fig. 2 is termed the falling-rate period, and, as shown in Figs. 3 and 4, it is typified by a continuously changing rate. Point A, where the constant rate ends and the drying rate begins to de crease, is termed the critical moisture content. The portion of the curves designated by CB 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 period is equiv alent 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 con stant rate of evaporation on the surface of the solid maintains the surface at a 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 TIME Flo. 4. Rate or Drying, -drar vs. Time 6 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. , to ^0se dryers in which heat is transferred to a wet solid by conduction "tough hot surfaces, and heat transfer by convection is not a factor, the ''et surfaces approach the boiling point temperature rather than a wetou|b temperature. When all the heat for evaporation in the constant-rate period is supplied . "to* SOS) a dynamic equilibrium is established between the rate of heat Thi 6r -- ^*e matorial and the rate of vapor removal from the surface, fofi ec*udtorium between heat and mass transfer rates can be expressed as where dw ft,Aat da " x k,,AAp d\0 dd ^ frying rate, pounds of water per hour. (1) 1028 CHAPTER 47 ,1954 Guide hi = total heat transfer coefficient, Btu per (hour) (square foot) (Fahrenheit degree): .; > ' ' ' A. = area of heat transfer and evaporation, square feet. . , X = latent heat of evaporation at ti, Btu per pound. * ht = mass transfer coefficient, pounds per (hour) .(square foot) (atmosphere). ) M = (1* -- *) = temperature difference between air and surface of evaporation, Fahrenheit degrees. ' J. = air temperature, Fahrenheit, ; . , f, = temperature of surface of evaporation, Fahrenheit. Ap = (p,, -- p) = vapor pressure difference, atmospheres. ' p, = vapor pressure of water at ti, atmospheres, p, = partial pressure of water vapor in air, atmospheres. When h, = hc, 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 (hc r|- hr) where hr is the radia tion coefficient and hc 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 conduction. When the surface is at the wet-bulb temperature, the value of Ap in millimeters of mercury, is almost exactly one-half the wet-bulb depression (ta -- f), in Centigrade degrees. , ' Effect of Air Velocity. The principal effect of air velocity is on hc and ks, 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 air velocity may be expressed by the following relationship:3 , A,, = 0.0128 G (2) where ' hn = convection heat transfer coefficient, Btu per (hour) (square foot) (Fahren heit degree). G = mass velocity of dry air, pounds per (hour) (square foot). For estimating the constant rate in drying from plane surfaces with air flow parallel to the surface of evaporation and with no radiation or conduction effects, the following heat transfer expression can be used: du> _ 0.01286 M ), ", ' de X M (3) where .. t. = wet-bulb temperature of the drying air, Fahrenheit degrees. Heat transfer coefficients, rather than mass transfer coefficients, should be vised to estimate drying rates, because heat transfer coefficients are generally more reliable, and, unless the temperature of the drying suna is measured, it must be calculated from heat transfer considerations beipre mass transfer coefficients can be applied for drying-rate predictions, assumption that the surface of drying is at the wet-bulb temperat of the air, introduces a more serious error in the computation of m transfer than of heat transfer. ^ Determination of True Surface Temperature. Frequently, radiation an conduction are of sufficient magnitude to cause the temperature of evap oration to exceed the wet-bulb temperature of the air. When this cc" it is necessary to estimate the true surface temperature in order to calcuia Industrial Drying Systems 1029 the constant rate. This may be done by means of a heat balance equating the total heat transferred by convection, conduction, and radiation to the latent heat of evaporation. Constant-Rate Period in Through-Circtdalimi Drying. The equation for estimating the rate of evaporation when air, flows across. a free water surface must be modified for the case of air-flow through a permeable bed of solids. The constant rate in through-circulation drying depends on the; air rate, air temperature, air humidity, size of the particles making up the permeable bed, and physical characteristics of these particles.4 The following general expression for the constant rate in through-circula tion drying for the system water and air, was developed5 from experiments on the rate of evaporation of . water from the surface of wet spheres and cylindrical particles with through-circulation of air: - ; where . dW _0A2aG TM{AH)m de Z)"*1 6McmG**AU xP.t>p" . . (4) : dW "jj = constant rate, pounds of water per (hour) (pound of dry stock). o = drying area, square feet per'cubic foot of bed volume. G - superficial mass velocity, pounds of dry air per (hour) (square foot). Affm = logarithmic mean of inlet and outlet humidity driving force across the air film adjacent to the particle through which the water vapor diffuses, pounds per pound (the. surface humidity is taken as the humidity corres ponding to the wet-bulb temperature of the drying air). p> = bulk density of dry granular bed, pounds per cubic foot. Bp = average diameter of particle, feet. Aim = logarithmic mean difference between temperature entering and leaving the bed and the wet-bulb temperature, Fahrenheit degree). c, = humid heat, Btu per (pound of dry air) (Fahrenheit degree). X = latent heat of evaporation, Btu per pound. Equation 4 applies when the Reynolds number DpGJy is greater than eu0, where y is the viscosity of the air stream. For values less than 300, a modification of Equation 4 has been presented.6 Evaporation from Liquid Drops. For the important problem of spray "ymg, evaporation rates of liquid drops must be estimated. Below a value of Reynolds number (DpG/y) of 10 for spherical particles, the heat transfer coefficient across the gas film surrounding the drop is given by where 2k, h D, (6) A - film heat transfer coefficient, Btu per (hour) (square foot) (Fahrenheit de gree). = thermal conductivity of gas film, Btu per (hour) (square foot) (Fahrenheit degree per foot). . ...... Pfluation 5 is applicable when the Reynolds number for liquid drops ,,n *han 10. Drop diameters are almost always less than 500 microns, a usually in the range of 20 to 150 microns. tran^f rate * evaporation of drops may be expressed in terms of heat i,,jS er r mass transfer. In terms of heat transfer, the evaporation rate w given by the equation: : 1030 CHAPTER 47 19S4 Guide to x where dw _ evaporation rate, pounds per hour. to ' A similar expression based on mass transfer is dv> . 2TrMd,Dc - (p. p.) RT (7) where df = molecular weight of the diffusing vapor. dr = diffusivity of the vapor, square feet per hour. T = absolute temperature of the gas, Fahrenheit degrees. R = gas constant, (cubic feet) (atmosphere) per (Fahrenheit degree), p, = vapor pressure at the particle surface corresponding to the liquid tempera ture, atmospheres. p. cs vapor pressure of liquid in the drying medium, atmospheres. Both Equations 6 and 7 are based on the assumption that Equation 5 applies. If Equation 6 is integrated for a constant drop diameter (t'.e., if it is assumed that the solid being dried in the liquid drop creates a struc ture which becomes rigid at a fixed Dp) and evaporation proceeds as from a pure liquid drop, an expression for the time of evaporation is obtained as follows: . likjiu f.) (8) where W8 ==> wtimatee,r hcoounrtse.nt of the drop as it enters the drying chamber, pounds per pound. p, = density of dry particle, pounds per cubic foot. The temperature difference between drop and gas (to -- O is essentially constant for a single drop evaporating in a large mass of gas. However, in spray dryers this is not true, and an overall average temperature differ* ence must be used in Equation 8 in this case. When the drop diameter varies as evaporation proceeds, the expression for the time of evaporation becomes plXKPqi)* ~ (Dm)1! (9) where pl = density of the evaporating liquid, pounds per cubic foot. Ppi = drop diameter at the start of evaporation, feet. D& = drop diameter of dry particle, feet. Equation 9 assumes that the drop density is essentially that of the liquid Drying at Air Temperatures above the Boiling Point of the Liquid. Whe the temperature of the drying air is maintained above the boiling point > the liquid being evaporated, or when superheated vapors are used w* drying, the usual equations for mass transfer, expressing rate of evaporation A Industrial Drying Systems 1031 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 conven iently on a basis of heat transfer, since a temperature difference must always exist in order that drying may proceed. At drying temperature above 260 F, recirculation has no retarding effect on the drying process. 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 sur faces, or on radiation, or both. This applies to drum dryers, agitated pan dryers, indirect continuous sheeting dryers, steam tube rotary dryers, vacuum rotary and vacuum tray dryers, and infra-red dryers. A principal difference between indirect drying and direct drying is that, with the former, the material is usually at a higher temperature than the surrounding air, so that heat is actually transferred to the air instead of from the air. Generally, the individual heat transfer coefficients for indirect dryers are difficult to determine or estimate, and therefore, an overall coefficient, as defined by Equation 10, is generally used: q = UA (t,, - t.) (10) where q = rate of heat transfer, Btu per hour. U =. overall heat transfer coefficient based on the temperature difference between the heating medium and the product, Btu per (hour) (square foot) (Fahren heit degree). (h = temperature of the heating medium, Fahrenheit. (. = temperature of the solid, Fahrenheit. The overall coefficient is a function of dryer type. Thus, in agitated pan dryers, U depends on the degree of agitation, temperature of the sur face, physical properties of the wet material, etc., and will sometimes vary throughout a drying cycle as the physical properties of the solid vary with a changing moisture content. As long as U and the temperature difference in Equation -10 remain constant, a constant drying rate will be maintained. However, as drying proceeds the material temperature will begin to increase after some critical moisture content is reached, and, as in the case of direct dryers, a fallingrate period is encountered. U is frequently defined, for the entire drying Period, on the basis of an overall mean temperature difference. There fore, q = UA (Ai)m (ID 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 f a constant rate of evaporation and a period in which the rate contin uously decreases. (See Figs. 3 and 4). 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 con sul- is less than the required final moisture content, the constant-rate Period will constitute the whole of the drying process. On the other hand, u the initial moisture content is less than the critical moisture content, as 1032 CHAPTER 47 1954 Guide1 in the case of some slow-drying materials, 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 zones which may be termed (1) the zone of nnsaturated surface drying, and (2) the zone where internal liquid flow controls. The zone of unsaturated surface drying follows immediately after'the 'critical point and results from a progressively decreasing wetted surface. With the surface* no longer completely wetted, dry portions of the solid protrude into the air film, so that the 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 representing rate of drying vs. water content of the solid is Straight in this region, as shown by fine AD in Fig. 3. The mechanism of drying is essentially the same 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 controls the drying rate, and in drying to low moisture contents, this period may be the principal factor determining the drying time. Studies of internal moisture flow have indicated the possibility of several controlling mechanisms, the more significant ones having been postulated previously as diffusion, capillarity and pressure gradients due to shrinkage. Of these mechanisms, internal moisture movement by diffusion has been treated extensively, while capillary flow and flow caused by shrinkage and pressure gradients, have received only preliminary consideration. When diffusion does control in the fafiing-rate period, it obeys the same fundamental laws Of diffusion as those applying to the diffusion of heat. On this basis, the integrated diffusion equation for the falling-rate period (for the case where the surface, is dry or at its equilibrium moisture content and the solid has a uniform initial moisture distribution) expresses the average moisture content as a function of time as follows: w - w. _ 8 r ig-MCWSi)1 _f. g-MitwItLi* . -L -4 g-lddlWIL)1 4 ... I 9 25 J (12) where W, To, W, = the moisture contents, on a dry basis, at any time 9; at 9 = 0, the start of the diffusional flow period; and in equilibrium with the ; external conditions, respectively, pounds of water per pound of dry solid. , . d = the liquid diffusivity, square feet per hour. . L = one-half, the. thickness of the solid layer through which the liquid is . diffusing, feet. . In Equation 12 it is assumed that evaporation is occurring from two opposite faces of the solid. When evaporation occurs from only one surface, substitute the total thickness of the solid layer for L in Equation 12. Equation 12 is based on the assumption that d is constant. However, this is rarely true, and d has been shown to vary with moisture content, temperature and humidity.7 When the time becomes large, a limiting form of Equation 12 is obtained as follows: W. Wo - Wo c-dcm.>' ** (13) Industrial Drying Systems 1033 From Equation 13 an expression for the rate of drying.may be derived to give dW ir*d ~d$ x where dW/d9 = drying rate, pounds per (hour) (pound dry material). Equation 14 states that the rate of drying, when internal diffusion con trols for long times, is directly proportional to the free moisture content (W - We),, the liquid diffusivity d, and that the time, of drying varies as the square of the material thickness. However, Equation 14 holds only when (W -- We)/(W0 -- We) <0.6. When this ratio exceeds 0.6, the curve of drying rate vs. moisture content is concave upward. Equations 12, 13, and 14 hold only for a slab-shaped solid, the length of which is large compared with its thickness. . The falling rate frequently can be expressed with fair accuracy over the required range of moisture content by an equation similar to Equation 14: (dI)r~K(w-w^ m where K is a function of the constant rate as follows: idW/de)o (To - Wo) (16) where (dW/de)o = the constant drying rate, pounds per (hour) (pound dry material). Wo = the critical moisture content, pounds per pound dry material. Substituting in Equation 16 the proper expression for (dW/ddc) the value of K becomes At(f. - t.) PolMWc -- Wo) (17) and hence, the falling rate for this case is given by fdW\ _ K(t. - to){W - Wo) \de), P.L\(Wo - Wo) (18) For materials obeying Equation 18, the drying time varies directly as the thickness. When the surface temperature in the constant-rate period >s at the wet-bulb temperature, L can be substituted for t,, and 0.0128 G0-8 can be substituted for h, in Equations 17 and 18. The drying time for each case of the falling-rate period may be obtained by integration of Equations 14 and 18, respectively, to give: 1. Diffusion law 2. Proportional-to-thickoess law pXUWo - Wo) 9, hd.to -- U) (20) 1034 CHAPTER 47 1954 Guide Table 1 gives an approximate classification of materials which are most likely to obey Equations 19 and 20. ' Equations 18 and 20 hold for cross-circulation (hying. When through- circulation drying is involved, the appropiate constant-rate expression given by Equation-4 must be used to determine K in Equation 16. Thus, for through-circulation drying in the falling-rate period when Equation 15 holds, the rate is given by 0-37c.aGl>-M(Ai),, p*D**W. - W.) or - ord (21) where the symbols have been defined for Equations 4, 12, and 16. Critical Moisture Content. In order to use the above equations for estimating the drying time in the falling-rate period, it is necessary to know values of the critical moisture content. Such values are usually difficult Table 1. Approximate Glassification of Materials Most Likely to Obet Equations 19 and 20 Material Obeying Equation 19 Materials Obeying Equation 20 1. Single-phase solid systems such as soap, gelatin, glue. 2. Wood and similar solids below the fiber saturation point. 3. Laststagesof drying starches, textiles, paper, clay, hydrophilic solids, and other materials when bound water is being removed. 1. Coarse granular solids, such as sand, paint pigments, minerals, etc. 2. Materials in which moisture flow occurt at concentrations above the equi librium moisture content at atmos pheric saturation, or above the fiber saturation point. to obtain without making actual drying tests which, in themselves, would give the required drying time and thereby obviate the necessity of the calculations. It appears that the constant-rate period ends when the moisture content at the surface reaches some specific value. If the rate of drying is great, the moisture gradients within the solid will be steep and the average moisture content considerably greater than that at the surface. It is for this reason that the critical moisture content (average through the ma terial) increases with increase in rate of drying, and with an increase m thickness of the layer being dried: Approximate Equations for Estimating Drying Time An estimate of the overall drying time for a given drying problem usually involves an estimate of the time required for the constant-rate period, plus an estimate of the time for the falling-rate period. An ap proximate equation for the overall drying time applicable to the cross circulation drying of materials of the type listed in Table 1 as obeying Equation 20, may be written as follows: (Wo - W,,)XLp. pJMW' - W') t W'-W' - +fit fit + fif = htU. (.) ht(l, - O g" W -- W. rw.-w. t, =B w,, -- w.] (22) Industrial Drying Systems \............. 1035 where ,, p.L\( We -- it') 1 a " At(t. - U) ~ IT . fit = total drying time, hours. ft, -- drying time for constant-rate period, hours. fit = drying time for falling-rate period, hours. W. = initial moisture content, pounds per pound of dry solid. Wo critical moisture content, pounds per pound of dry solid. . W. = equilibrium moisture content, pounds per pound of dry solid. \V = moisture content at time fit, pounds per pound of material. At = total overall heat transfer coefficient Btu per (hour) (square foot) (Fahren heit degree). U = air temperature, Fahrenheit. U = temperature of surface of material, Fahrenheit. L = depth of material in tray, feet. X = latent heat of evaporation at t,, Btu per pound, p, = density of dry solid, pounds per cubic foot. Equation 22 will apply to those materials satisfying Equation 20 when drying to very low moisture content is not involved. For through-circulation drying, an expression similar to Equation 22 is obtained. Thus, the total drying time for through-circulation drying is given by Hr..- w. W, - W'l fit = B' |_1F. - w. + log. w- W.J (23) where 2.7ff.XDp qr0 - IF.) The drying times estimated from Equations 22 and 23 apply only to cross-circulation drying and through-circulation drying, respectively. Drying times for other methods, such as rotary drying or drum drying, must be estimated by other methods. Equilibrium Moisture Content In the drying of solids it is important to distinguish between hygroscopic ana non-hygroscopic materials. A hygroscopic material is one which retains a definite percentage of moisture under definite conditions of air humidity. This bound moisture is in a state of equilibrium with the water 'apor in the surrounding air, and a decrease in the water vapor content will ecrease the amount of equilibrium bound water. Water so retained y a solid in equilibrium with the humidity of the surrounding air, is csignated as the equilibrium moisture content. Such moisture may be held adsorbed surface films or condensed in fine capillary structures at mouced vapor pressure. hi^Tr e<Iu'libriurn moisture content varies with the temperature and umidity of the surrounding air. Consequently, any correlation of equilie 11111 moisture content should take these two factors into account. Howcont' ^ 'W temperatures, e.g., 60 to 120 F, a plot of equilibrium moisture ndp t Percent relative humidity, expressed as 100 {p/p,), is essentially dm Jleri<lent f temperature. Such a plot usually results in a curve of ble curvature with a point of inflection (see Fig. 5). he equilibrium moisture content at a given relative humidity is not 1036 C. HAPTER 47 ' 1954 G`u"idSe'-: independent of temperature for all temperature ranges. As the tempers* ture increases at a given relative, humidity, the equilibrium moisture con tent tends to decrease. A limiting condition exists when temperatures above the boiling point of the adsorbed liquid-are encountered. In such cases, relative humidity loses its significance with regard to equilibrium moisture content, and complete dryness of most hydroscopic materials is possible, even when a large amount of vapor exists in the atmosphere. This makes possible drying by means of superheated vapors. ' In the special case of the dehydration of hydrated inorganic salts, such as copper sulfate, sodium sulfate, and barium chloride, temperature and humidity are very important in obtaining the desired degree bf dehydra tion. Thus, in the drying of wet salt crystals to obtain a product with the maximum number of molecules of hydrate water, it is necessary to dry under closely controlled conditions of air temperature and humidity. Generally, the temperature is low and the humidity is high. The equilibrium moisture content of a hydroscopic material may be determined-in a number of ways. The requirement for any method is a Industrial Drying Systems 1037 conditions of air humidity and temperature. Drying costs can be un necessarily high if a material is dried to a moisture content less than that which it normally possesses in equilibrium with atmospheric air. For example, if a dryer dries a material to 1 percent final moisture, and on standing under normal atmospheric humidities it regains moisture to 5 percent, the material is considered to be overdried, so that probably the dryer would be capable of a considerably higher capacity and efficiency with a 5 percent final moisture content. Applications of Hygrometry to Drying Drying of a solid by hot air or hot gases may be divided into two proc esses: (1) transfer of heat to evaporate the water, and (2) removal of the source of constant humidity and constant temperature air into which the sample may be placed. The determination may be made under either static or dynamic conditions, the latter being preferred if the data are to be used for drying calculations. . Probably the simplest static procedure is to place a series of samples in ordinary laboratory desiccators over sulfuric acid solutions of known concentration, which thereby produce atmospheres of known relative humidity. The sample in each desiccator is weighed periodically unhl * constant weight is obtained. The moisture content at this final weign represents the equilibrium moisture content for the particular relative humidity involved. The value of equilibrium moisture content so o tained will depend oh whether it is reached by losing moisture, as in drying) or by gaining it, i.e., whether the sample is at a moisture content higher lower than the equilibrium value. The equilibrium moisture contee^ reached by losing moisture, i.e., by drying, is generally higher than tb* reached when moisture is adsorbed, as shown in Fig. 5. The equilibrium moisture content of a solid has particular significance in drying because it represents a limiting final moisture content for sped '?,P"r by the air or gas stream. Likewise, two processes are involved in tne design and operation of direct dryers: (1) the estimation of the drying rate or drying time, and the effect of the external variables on the drying ate, and (2) the calculation of the heat and air quantities required. The rst estimates concerning drying time have been considered in the first Part of this chapter. The second calculations are based on the use of the Psyehronietric chart, Fig. 6. In drying, the humidity chart finds its greatest utility in analyzing the Pfrf*011 of existing dryers, in making design calculations, and in checking hu vrti0rlS a'r Quantities. It is equally useful in interpreting the li rnicllty"temperature relations within the dryer. The adiabatic cooling ancf r ^le I\uTMdity chart indicate the relation between the temperature drv humidity which are present in air passing through an adiabatic l ne in which all of the sensible heat given up by the air in cool- ofth Ufec*to evaporate water from the wet stock. Referring to the section tion V "'u?*dity chart shown in Fig. 7, where AB is one adiabatic satura- une, it follows that air entering an adiabatic dryer at temperature L 1038 . .. CHAPTER 47 and a humidity Hi will cool, following this cooling line toward pointed; Air leaving with a humidity Hi will consequently have cooled to t*, th'e wet-bulb temperature of the air throughout the dryer being t. When heat is lost to the surroundings, the operation" is-somewhat lower thanTj so that the actual" humidity-temperature relation is represented by the line Bb, having less slope than the adiabatic saturation line. The ratio (ti -- tj)/(tj -- ts) then gives a measure of the evaporative efficiency of the dryer. For the case of dryers containing steam coils maintained at a con stant temperature, the humidity-temperature relation is obviously repre sented by the vertical line Be, assuming the initial and final humidities to be Hi and H2 as before. The heat supplied within the dryer itself is usually less, but may be greater, than the total heat requirements of the dryer. If less, the cooling is indicated by some such line as Bd, and if greater, by a fine such as Be having a positive slope. Industrial Drying Systems 1039 The use of Fig. 8 in practical drying problems is as follows: Since the drying conditions of temperature and relative humidity are fixed, the corresponding absolute drying rate is read from Fig. 8. This value is then multiplied by the correction factor corresponding to the air velocity employed. The rate so obtained, however, does not include any effects of radiation or of conduction through unwetted surfaces. These effects tend to increase the rate of evaporation so that the chart is conservative.5 It has been demonstrated empirically for certain materials that the rate of drying during the falling-rate period is approximately proportional to the-free water content of the material. Actual calculations of drying time Fig. 7. Humidity-Temperature Relations in Dryers1 DRYER CALCULATIONS As shown in the foregoing part of this chapter calculations for drying during the constant-rate period are different from those applying to the falling-rate period, and in contrast are subject to relatively simple mathe matical analysis. The constant rate of drying by convection is directly proportional to the temperature difference between air and wet solid, and also proportional to the 0.8 power of the air velocity as shown by Equation 3. Usually the wet surface is assumed to attain the wet-bulb temperature of the air passing over it, and evaporation takes place at a constant rate under equilibrium conditions. This is a conservative assumption, however, and when con duction and radiation effects occur, the constant rate may be increased by 30 to 60 percent over that for pure convection. Fig. 8 permits a ready estimate of the constant drying rate for various air temperatures and 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 fr 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 in any given problem is incor porated in Fig. 8. This curve is based on the variation of drying rate wiw the 0.8 power of the velocity, as given by Equation 3. during the falling-rate period for this case require only a knowledge of the critical moisture content and the constant rate. For other cases of the falling-rate period, calculations are not feasible. Consequently, it is best |9 determine drying times for design purposes by means of pilot tests. However, when tests are not feasible, drying times may often be estimated approximately from Equations 22 and 23. The following nomenclature will be used in the discussion of design cal culations: = humidity ratio of air, pounds of water vapor per pound of dry air. = pounds of dry air supplied to the dryer per unit of time. = pounds of stock dried per unit of time in a continuous dryer. = pounds of stock charged per batch to a discontinuous dryer. ~ time, hours. @ ~ total heat supplied to the dryer, Btu. 1040 ' CHAPTER 47 1 = air temperature, Fahrenheit. I' = stock temperature. Fahrenheit. t" = average stock temperature over short time interval, in a batch uryer, Fahrlt enheit. = wet-bulb temperature, Fahrenheit. . ift, Si = specific heat of the stock, Btu per pound. kb Q,, = total radiation and conduction losses, Btu per hour. W =. pounds of water per pound of dry stock. , X = heat of evaporation of water, Btu per pound. , c. = humid heat of air, i.e., heat necessary to raise 1 lb of dry air + H lb of steam, . 1 F deg. Subscript (1) designates conditions at the point where the material in question (air or stock) enters, and (2) where it leaves the dryer. Air dryers may be divided into two classes, batch and continuous. In any continuously operating dryer, the relation between moisture content of the stock and quantity of air required for the drying operation is given by the equation AT. (Hi - Hi) = S(1F, - IF,) (24) where Hi is constant. ` In discontinuous dryers, the drying operation is given by the equation W.(H, - H,) = S' ~ (25) where if2 is a variable during a portion of the cycle. In the continuous dryer, the heat consumption per unit time is ? = IF.c.iO, - /,) + H.(x, + l, - Cl) (Hi - H,) + S(i', - r,)(s, + fF.) + Q,. (26) e Equation 26 assumes continuity of operation. For charge or batch operations, the total time of the drying cycle may be broken up into a number of periods, sufficiently short so that over each period average values of t, t' and H may be employed, provided the third term of the right hand member of the equation is modified to read: - r,) (s, - IF,) and in the second term ('2 be replaced by ' 2 Theoretically, these periods should be very short and the equation inte grated. Practically, the error introduced by using a small number 0 long periods and employing average values of the variables over each, not serious. The evaluation of Equation 25 may be approximated in a similar manner. , The first term of the right hand member of Equation 26 represents bea lost as sensible heat in the effluent air. In many drying operations TM becomes excessive. Each pound of air supplied should remove the ma mum amount of moisture. This is best accomplished by bringing the ai into contact with the stock with sufficient intimacy so that the air leaving Industrial Drying Systems 1041 the dryer is saturated, or nearly so. Countercurrent, as against parallel, flow of air and stock gives rise to optimum operating conditions, resulting in a minimum quantity of air required (Nm), and a corresponding minimum loss, as sensible heat, in the exit air. Similarly, continuous operation is superior to intermittent operation. . Despite the fact that the sensible heat loss, increases with the rise in temperature of the air, the percentage of heat lost from this source de creases if the increase in moisture carrying capacity of . the air (due to high temperature) is actually utilized. To secure maximum thermal effi ciency in drying, a high drying temperature and high saturation of the outlet air are imperative. , The second term of the right member of Equation 26 represents the latent ' heat of evaporation of the water plus the heat to raise this water to the temperature of evaporation. The third term of the equation represents heat to raise the temperature of the stock plus the water which remains unevaporated in the stock. The changes taking place in the air during the drying process can be illustrated on the skeleton psychrometric chart, Fig. .9. The case illus- Fio. 9. Changes in Air Dhbinq: Drying Process trated is typical of tunnel and rotary dryers where heat is applied to the air at one point only. After the first adjustment stage, during which both the material and the dryer reach the working temperature, the only heat Josses from the dryer are those of radiation and conduction from the hous- and these are practically negligible for an insulated dryer. Hence, the drying process can be considered to be adiabatic: If 100 percent outside air is used, the air can be considered to enter at point A, Fig. 9 (the prevailing outside, air condition), and be heated to point B (the maximum permissible temperature 4, or the temperature etermined by previous test). As the air' evaporates moisture, it cools long the constant wet-bulb line; BD to point C. The difference between moisture content of air at B and at C represents the moisture pick up 1 the air. The maximum possible pick up from B to D is never achieved practical dryers, the actual pick, up being anywhere from 10 to 75 per^nt of the maximum. J.n order to conserve heat and to control the wet-bulb temperature at on F- t"e tak?s Place, recirculation is used. The process is shown rig- 9. The outside air at A is mixed with recirculated air until the oisture level is raised to the desired point. The mixture is represented point M, the heaters heat the mixture to the desired dry-bulb tempera at point S. The moisture is picked up from S to L. Point L is the onaition at which air is exhausted. ' 1042 CHAPTER 47 1954 Guide Industrial Drying Systems 1043 Actual dryer operation is somewhat more complicated because even-if radiation and conduction losses are neglected, the wet-bulb temperature of the air remains constant only as long as surface evaporation of water is taking place. When sub-surface evaporation is occurring, some heat from the air is used to heat the material and hence, there is a drop in wet- bulb temperature. Fig. 10 illustrates the drying process in a tunnel dryer in which the air is flowing parallel to the product.2 ; In design calculations using Equation 26, the following steps outline the procedure: 1. The unit drying rate, pounds of water per hour, is determined from the experi mental drying time curve and the amount of product to be dried per hour. The drying time may also be approximated from previous experience. 2. The experimental data or experience also determine the drying condition, i.e., point L Fig. 9. This fixes H,. Where experimental data are lacking L may be ap proximated from Regain Tables (see Chapter 45 Industrial Air Conditioning) since the relationship between the vapor pressure in the product and in the air at equilibrium for the desired final moisture content must prevail in the dryer. The air temperature must be not greater than the maximum permissible product temperature. In artificial systems, radiating surfaces, heated by steam, electricity or other means, afford a good method of heat distribution and control. Ra diant heating sets up convection currents, and 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 temperatures 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 5. 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 certain in dustries as practicable for their specific problems. An example of success ful application is found in the drying of lacquers. Lacquers and similar surface films can be very effectively dried by radiation. Special electric lamp units have been developed which give off a high percentage of infra-red and similar heat rays. For continuous manufacturing processes these units are mounted in tunnels through which conveyors pass. For local applications, as for example paint drying in automobile repair shops, they may be mounted on portable racks. Ob jects of relatively large surface area in proportion to their weight, and fabricated materials having a rather high heat absorption, may be satis factorily heated by such a source. 10.Fig. Temperature and Moisture Conditions in a Tunned Dryer Parallel Flow Air and Product 3. The rate of air circulation N. must be determined and also the supply air con dition S. In the design of some dryers, such as rotary or tunnel types, it is customary to determine S first and then to calculate the air rate N. In other types of dryers, such as tray dryers or through circulation dryers, where a fixed air velocity is main tained, N. is calculated first and then point S is found. Because of the many vanables involved, it is generally not possible to select S except on the basis of past ex perience or on the basis of experimental drying tests. 4. The prevailing outside air conditions establish point A and hence, the line AL. The percent of recirculated air can then be calculated. 5. The physical arrangement of the dryer must then be selected to handle the desired quantity of product, and at the same time circulate the calculated air quantity at the desired velocity. 6. Equation 26 can then be used to calculate the heat requirements. 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 ol air and water vapor. The methods of heat transfer are radiation, con duction 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-continuous and continuous. For drying, baking, pre-heating and de-hydrating, where a low tem perature infra-red heat source is desired, or where use of glass-enclosed radiant lamps is objectionable for safety reasons, electric heating units employing low temperature metal sheathed resistors, are available. Conduction Drying Drying rolls or drums, Fig. 11,8 flat surfaces, open kettles and immersion heaters are examples of the direct-contact method^ Intimate contact of the material with the heating surface is important, and in some cases agita tion is desirable to increase the uniformity of heating or to prevent over heating. Greatest resistance to heat transfer occurs on the air side of the material being dried. The rate of heat transfer from the surface of the heated inaterial to the air, and hence the rate of drying, may be increased by (a) forced convection or air circulation, and (b) vacuum operation to lower the boiling point of the liquid being evaporated. 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 uucro-organisms. This has come to be known as freeze drying or drying by sublimation. The material to be dried is first frozen and then placed >n a high vacuum chamber connected to extremely low temperature con densers. The water is removed by vaporizing from the solid directly t0 kbe gas without ever becoming liquid. Radiant Drying Convection Drying (Direct Dryers) Sun drying, the oldest form known to man, is still practiced where the material is amenable to such treatment, where the necessary time can be allowed, and where there is little danger of rain or atmospheric pollution- A limited amount of convection drying takes place in almost any dryer "ueh as those described in the preceding paragraphs. However, to be ik 1044 CHAPTER 47 1954 Guide Industrial Drying Sections 1045 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 mechan ical 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 being dried through the air stream. (See Pig. 12). The driers may be heated directly or indirectly, and the air circulation may be paral lel or counter-flow. A variation is the rotating louver type dryer, which introduces the air beneath the flights thus securing very intimate contact. Cabinet and Compartment Dryers. These are generally considered batch dryers wherein each charge is dried to completion before removal.8 A wide range includes types from the heated loft with only natural con vection, and usually poor and non-uniform drying, to the self-contained units with forced draft and properly designed baffles which give positive results. It is also possible to evacuate some of the systems for low tem perature drying of delicate or hygroscopic materials. These dryers are usually loaded with material spread in trays to increase the exposed surface. The trays are loaded directly into the dryer or may be stacked on trucks which are wheeled in. (See Fig. 13) Tunnel Dryers. Tunnel dryers are a modification of the compartment dryer, and as a rule are continuous or semi-continuous in operation. Heated air or combustion gas is usually circulated by means of fans, although a few natural draft units are still in use. The material is handled on trays or racks on trucks, and moves through the dryer either intermittently or continuously. The air flow may be parallel, counter-flow or a combina tion 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 Fig. 13. Compartment Dryer, Showing Trucks, with Air Circulation' combination of directions. By reheating, the air in this type of dryer or recirculating it, a high degree of saturation is achieved before exhausting the air. This reduces the waste of sensible heat. A variation of this type dryer is the strictly continuous'type having one or more mesh belts which travel through the dryer carrying the prod uct, such as Fig. 14. Innumerable combinations of temperature, hu midity and air direction and velocity are possible.. The labor requirement is low on such a dryer, as it can be loaded and unloaded mechanically. There is the disadvantage 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. The liquid is atomized by means of pressure nozzles, air jets or centrif ugal bowls into the air stream of a tower or chamber. Inlet air tempera-; hires may run from 250-300F 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 is separated from the air by cyclone separators which are sometimes followed by cloth bags r scrubbing towers. Because of the high inlet temperatures and the relatively large volume f air required, the efficiency of the spray dryer is not too good and, conse quently, is seldom used for dilute solutions (less than 30 percent solid). 15 shows a typical arrangement for a spray drying system.8 A common and important feature of all spray processing is the direct conversion of the spray liquid to a granular product suitable for packaging Fig. 12. Cross Section and Longitudinal Section Through Circulation Darn' Fig. 14. Section of Continuous Dryer, Blow-Through Type 1046 , . CHAPTER 47 1954 Guide without grinding or other intermediate handling. Another aspect is the unusually high rate of drying attained. In a well designed system 15 to 30 seconds is a fair time for the passage of the sprayed particle through the drying zone; the particle temperature need not rise materially above the wet-bulb temperature of the drying air. This makes the process partic ularly adaptable to the drying of heat-sensitive material, some of its most important applications being the drying of milk, eggs, potato flour, soap and blood.9 SOLUTION OF TYPICAL DRYING PROBLEM Since there are so many types of dryers which may be used, and so many special conditions surrounding each particular problem, it is usually recommended that those having experience with the dryer to be used be consulted. The following example, however, will serve as a guide for typical dryer calculations.10 Example i: Assume 900 lb per hour of ceramic powder is to be produced. The powder has a specific heat o! 0.22 and density of 98 lb per cu ft, wet. Initial moisture content is 19 percent on a wet basis; final moisture content is to be one-half ot one percent on a wet basis. A continuous belt dryer is a logical choice, and previous experience indicates that rubber belts will withstand temperatures up to 200 F, which is also about the iugnesi desirable product temperature. Experience also indicates that a drying time oi min is possible at about 160 F dry-bulb and 100 F wet-bulb. - Eftecthm Belt Length Cgqrr^l1 SeCTKM A-A Fig. 16. Continuous Belt Dbyeb fob Cebamic Powdeb10 Industrial Drying Systems 1047 Step 1: Let x Then, pounds moisture at final condition. ^ = 0.005 or, x = 4.5 lb moisture and therefore the solid will amount to 895.5 lb. Likewise the weight of the initial moisture x can be found from x 895.5 -f x 0.19 or, x = 210 lb. The weight of moisture to be removed is 205.5 II? per hour, and wet material enter ing dryer is 1105.5 lb per hr. Step S: Previous tests indicate that a i in. layer of powder gives satisfactory re sults, and that a desirable air velocity is 50 fpm applied at a right angle to the belt. Based on 45 min (f hr) drying time, the dryer 30 bolding capacity will have to be 1105.5 X 0.75 = 830 lb of wet material or gg- = 8.45 cu ft of material. Assuming a 48 in. wide belt with an effective 42 in. width for the product, each foot of belt length carries 0.146 cu ft or 14.3 lb of wet material. Hence, the linear feet of 830 - belt must be j^--g = 58 ft and the total area of exposed product is 232 sq ft. Based on 50 fpm velocity directed at a right angle to the belt the total air circulation will be 232 X 50 = 11,600 cfm. For space economy and in order to expose periodically fresh layers of powder to air, a multiple vertical belt arrangement (Fig. 16) with belts traveling in opposite direc tions, IS selected. Three belts each 19.4 ft long will be required. Fig. 16 illustrates the physical arrangement of the dryer." The housing will Be about 25 ft long 8 ft wide and 7 ft high. Step S: At the drying conditions of 160 F dry-bulb and 100 F wet-bulb, the air moisture content (from Fig. 6) is 0.028 lb per pound of air. Make-up air will be at 80 F dry-bulb and 72 F dew-point (summer weather), or a humidity of U.U168 lb per pound of air. The ptcfc-up is therefore 0.0280 -- 0.0168 or 0.0112 lb per pound of air. Then ~ 18400 lb of air per hour or 307 lb per min. At the elevated temperature, the total air quantity of 11,600 cfm represents 675 lb oi air per min. Hence, Make-up air =* 46 percent Recirculated air = 54 percent tpmfep j*V^though the drying condition and drying rate should preferably be de- rmined from experience or test results, the drying conditions can sometimes be In }? ec* " the re8ain characteristics of the product or a similar product are known. r . ase^h regain characteristics of clay could be used as a guide. Inspection of 0 v typical clays indicates that at about one-half of one percent the vapor 0r . SUI" . the moisture in the product is about 0.7 in. Hg less than the vapor pressure tem 66 rnoi8ture at the product temperature. An assumption is made that the product rei>!ya^ur? aPProx*mate3 the air wet-bulb temperature. If an assumption is made esti F j the percent recirculated air the desired vapor pressure in the dryer can be mated. For example assume a use of 46 percent outside air or 307 lb per min. tii iyi r e r en t"e moisture pick-up -- qq x2Q7 = ^^ Per Poun^ of air, with a consequent ajr^?( -f- 0.0112 == 0.0280 lb of moisture per pound of air in the leaving outside sure nf fiT ^as abut 1.25 in. Hg vapor pressure. This is assumed to be the vapor pres- uct to tiie moi8ture in the product, and thus the vapor pressure of free water at prod- 1 oc lnRera^ure can be 1.25 + 0.7 = 1.95 in. Hg. The temperature corresponding to a-et-hi ik ^18 anc^ thus the air wet-bulb can be estimated to be 100 F. At 100 F ture ia i J^r?Pera*'u.re an<^ ^ moisture per pound of air, the dry-bulb tempera- suits Obviously, the assumed percentage of recirculated air affects the re- recj' aQd therefore it is important that it be based on experience. About 50 percent ulation is reasonable for the type dryer considered in this example. |: I : T: I: : i f :i i ; :' V: j. is 60 X 675 0.0051 lb. 0.0280 -- 0.0051 = 0.0229 lb moisture per lb of air for the supply air. : Assuming an existing wet-bulb of 100 F, the supply air dry-bulb will be 182 F. The mixture of recirculated air at 160 F dry-bulb anu 100 F wet-bulb> with outside air at 80 F dry-bulb and 72 F dew-point, will be at approximately 120 F dry-bulb and 89 F wet-bulb. . . Step 6: The heat required may be determined from Equation 26 by substitution of the following values: N& = 307 X 60 = 18420 lb of air per hr; S -- 900 lb; c. = 24 + OAS^0'028 H2'-2y) = 0.251; h = 80 F; l, = 160 F; h' = 100 F; X = 1100 (approx.); W -- 0.005 lb; $1 = 0.22. Q = 18420 (0.251) (160 - 80) *+ 18420 (110 + 160 - 100) (0.028 - 0.0168) + 900 (100 - 80) (0-22 + 0.005) + Qn = 609,000 Btu per hr 4- QTM - The heat input requirement is therefore 609,000 Btu per hr plus radiation and con vection losses (Qrc) which may be computed from the known construction of the dryer surfaces and the heat transfer coefficients. Summer conditions were used in Example 1 in order to obtain the maximum heat requirement which would be the case, except under the unusual condition where r&Qi* ation and conduction losses are a large percentage of the total. In winter it is usually possible to take advantage of drier makeup air, and either speed up the process or operate at a lower dry-bulb temperature. . Controls for the system selected for Example 1 would consist of a thermo stat in the main return air duct controlling the heat input to maintain constant dry-bulb temperature. A wet-bulb controller in the return os culating duct would maintain constant desired wet-bulb temperature by simultaneous positioning of three sets of dampers in the makeup air, tbe exhaust air and the recirculated air ducts. LETTER SYMBOLS USED IN CHAPTER 47 A ,=. area of heat transfer and evaporation, square feet. a = drying area, square feet per cubic foot of bed volume. B -- a constant (for use in Equation 22). . B' = a constant (for use in Equation 23). c, = humid heat, Btu per (pound of dry air) (Fahrenheit degree), d = diffusivity of the liquid or vapor, square feet per hour. Z)p = average diameter of particle, feet. Dpi = drop diameter at start of evaporation, feet. Dpj drop diameter of dry particle, feet, e =.Naperian base of logarithms = 2.718. G -- mass velocity of dry air, pounds per (hour) (square foot). . &Hm logarithmic mean of inlet and outlet humidity driving force across _ air film adjacent to the particle through which the water vapor dinusra, pound per pound. (The surface humidity is taken as'the humidity c responding to the wet-bulb temperature of the drying air). , Hi = humidity ratio of entering air, pounds of water vapor per pound oi i Hi = humidity ratio of leaving air, pounds of water vapor per pound ofdrysb' h = film heat transfer coefficient, Btu per (hour) (square foot) (FaUrenu h, = coefficient of heat transfer by convection, Btu per (hour) (square oo (Fahrenheit degree). ,, . , ,,,,,, rnot) h, - coefficient of heat transfer by radiation, Btu per (hour) (square w - (Fahrenheit degree). . ,, , , . ,,,,,, foot) At = total gas .film heat transfer coefficient, Btu per (hour) (square Fahrenheit degree). . K = a constant (a function of the constant drying rate). Industrial Drying Systems 1049 h = gas film thermal conductivity, Btu per (hour) (square foot) (Fahren heit degree per foot). Jr. = mass transfer coefficient, pounds per (hour) (square foot) (atmosphere). L -- material thickness, feet. Af = molecular weight of the diffusing vapor. JV. = dry air supplied to the dryer, pounds per hour. Ap = Ps -- p. = vapor pressure difference, atmospheres. p = vapor pressure of water at U, atmospheres. = vapor pressure at the particle surface corresponding to the liquid tem perature, atmospheres. p. => partial pressure of water vapor in air, atmospheres: ` p. = vapor pressure of liquid in the drying medium, atmospheres. Q= radiation and conduction loss, Btu per hour. Q = total heat supplied to dryer, Btu. q = rate of heat transfer, Btu per hour. R = gas constant (cubic feet) (atmospheres) per (Fahrenheit degree). S = weight of stock dried in a continuous dryer, pounds per hour. S' - weight.of stock charged in a discontinuous dryer, pounds per batch, s = specific heat of stock, Btu per pound. T = absolute temperature of the gas, Fahrenheit. t. = air or gas temperature, Fahrenheit. fh = temperature of the heating medium, Fahrenheit. U = temperature of particle, solid or surface of evaporation, Fahrenheit, t, = wet-bulb temperature of drying air, Fahrenheit. ti = entering air temperature, Fahrenheit. ti -- leaving air temperature, Fahrenheit. ti = entering stock temperature, Fahrenheit. h' = leaving stock temperature, Fahrenheit. I" = average stock temperature over short interval of time, in batch dryer (ti" = entering, t." = leaving) Fahrenheit. At = (U -- l,) -- temperature difference between air and surface of evapora tion, Fahrenheit. Aim = logarithmic mean between temperature entering and leaving the bed and the wet-bulb temperature, Fahrenheit. ' U -- overall heat transfer coefficient, Btu per (hour) (square foot) (Fahren heit degrees temperature difference between heating medium and prod- w yct)' *r = moisture content on dry basis at any time 0, pounds of water per pound. = critical moisture content, pounds water per pound dry material. H'd = water content, dry basis, of the drop as it enters the drying chamber, pounds per pound of dry solid. ' IF, = moisture content at equilibrium with external conditions, pounds per pound dry material. IF, = initial moisture or moisture content at start of diffusional period, pounds per pound. ' w -- pounds of water. aw de ~ drying rate, pounds of water per (hour) (pound dry material), t = constant drying rate, pounds per (hour) (pound dry material). dejt ~ falling rate, pounds water per (hour) (pound of dry stock). dw ~dd ** drying rate or rate of evaporation, pounds of water per hour (Eq. 1). 9 = time, hours. . 9 = drying time for constant rate period, hours. "f = drying time during falling rate period, hours. "t = total drying time, hours. A = latent heat of evaporation at f,, Btu per pound. = viscosity of the air stream, pounds per (hour) (square foot). Pl = density of evaporating liquid, pounds per cubic foot, e, -- bulk density of dry granular bed, density of dry particle, pounds per cubic foot. ' 1050 . CHAPTER 47 1954 Guide REFERENCES 1 Drying, by W. R. Marshall, Jr. and S. J. Friedman, Perry's Chemical Engineere' Handbook, McGraw-Hill Book Co., Inc., New York, 3rd Edition, 1950. Indicated material supplied by W. R. Marshall, Jr. and S. J. Frie'dman, authors of the Section on Drying in the 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' Handbook. The Drying of Foods, by W. R. Marshall, Jr. (Heating, Piping and Air Condition ing, September to December, 1942, and November and December, 1943). Drying Materials in Trays, by C. B. Shepherd, C. Hadlock and R. C. Brewer (Industrial and Engineering Chemistry, April, 1938). 4 Drying of Solids by Through-Circulation, by W. R. Marshall, Jr. and 0. A. Hougen (Transactions, American Institute of Chemical Engineers, 1942). ` Heat, Mass and Momentum Transfer in the Flow of Gases through Granular Solids, by B. W. Gamson, G. Thodos and O. A. Hougen (Transactions, American Institute of Chemical Engineers, 1943). 4 Mass Transfer in the Flow of Gases through Granular Solids Extended to Low Modified Reynolds Numbers, by C. R. Wilke ana 0. A. Hougen (Transactions, Ameri can Institute of Chemical Engineers, 1945). Limitations of Diffusion Equations in Drying, by 0. A. Hougen, H. J. McCauley and W. R. Marshall (Transactions, American Institute of Chemical Engineers, 1940). What the Air Conditioning Engineer Should Know About Drying (Beating and Ventilating, December, 1942). ` Spray Drying, by Ben B. Fogler and Robert V. Kleinschmidt (Industrial and Engineering Chemistry, December, 1938). 10 An Introduction to Convection Drying and Drying Calculations, by V. P. Victor {Heating and Ventilating, Vol. 41, Dec. 1944, p. 67). BIBLIOGRAPHY The Temperature of Evaporation, by. W. H. Carrier (A.S.H.VJE. Transactions, Vo). 24,1918, p. 25). Thermodynamic Properties of Moist Air, by John A. Goff and S. Gratch (A.S.H.V.E. Transactions, Vol. 51, 1945, p. 125). Factors Influencing the Performance of Rotary Dryers, by C. F. Prutton and C. O. Miller (Transaction*. American Institute of Chemical Engineers, Part 1, February, 1942; Part 2, August, 1942). Drying of Solids by Through Circulation, by W. R. Marshall and O. A. Hougen {Transactions, American Institute of Chemical Engineers, 1942). -- Factors That Influence Dryer Performance, by A. Weisselberg {Chemical and Metallurgical Engineering, August, 1932). Typical Dryer Calculations, by O. A. Hougen {Chemical and Metallurgical Engineering, January and March, 1940). * Symposium on Drying, Articles by W. K. Lewis, W. H. Carrier, A. E. Stacey, Jr., R. S. Fleming, R- G Meta, G. B. Ridley, C. O. Lavett, D. J. Van Marie {Industrial and Engineering Chemistry, May, 1921, PP- 427-460). . Studies in Rotary Drying, I and II, by S. J. Friedman and W. R. Marshall, Jr. (Chemical Engineeruw- Progress, 1949). . Symposium on Drying (Industrial and Engineering Chemistry, 1938). ,^ Principles of Drying Lumber and Humidity Diagram, by H. D. Tiemann (Forest Service Bulletin, ltw 1912). _ The Drying of Solids, by T. K. Sherwood (Bulletin, Massachusetts Institute of Technology, Nos. 237, 247, and 258). Radiant Energy Drying with Heat Lamps, by T. P. Brown (Metal Industry, Vol. 37. Dec. 1939, p- 607). Drying by Sublimation, by E. W. Flosdorf (rood Industry, Vol. 17, Jan. 1945, p. 607). Evaporative Drying System, by F. H. Slade (Food Manufacturing, Vol. 18, March, 1943, p. 70). High Frequency Methods in Gluing and Drying Wood, by I. R. Berkness (Wood Products, Vol. 45, IM' p. 12). . Development of the Unit Operations of Chemical Engineering: Drying, by T. K. Sherwood (Chertaan <fe Metallurgical Engineering, Vol. 42, p. 214). The Spray Dryer--Its Possibilities in Industry, by D. W. Biocheno (Food Manufacturing, Vol. 19, Junft 1944, p. 195). r Mechanism and Rate of Drying by Near-infra-red Radiation, by L. E. Stout, K. J. Caplan and W. u Baird (Transactions American Institute of Chemical Engineers, Vol. 41, 1945, p. 283). ,. Some Engineering Problems of the New Vegetable Dehydration Industry, by W. B. Van Ajsd (A.S.H.V.E. Transactions, Vol. 49, 1943, p. 49). . Electronic Dehydration of Foods, by V. W. Sherman (Electronics, Vol. 17, 1944, p. 94). Air Conditioning and Engineering, American Blower Co., 1935. Drying in Industrial Plants, J. O. Roes Company. - Elements of Chemical Engineering, by Badger and McCabe (McGraw-Hill Co., 1931). Fan Engineering, Buffalo Forge Co. . Die Trockentechnik, by M. Hirsch (Julius Springer, Berlin, 1932). Drying (Kent's Mechanical Engineers Handbook). Drying, by W. H. Carrier (Mark's Mechanical Engineers Handbook). Kiln Drying of Lumber, by A. Koehler and R. Thelen, New York, 1926. - Kiln Drying of Lumber, by H. D. Tiemann (Lippincott, 1920). CHAPTER 48 TRANSPORTATION AIR CONDITIONING Railway Passenger Car Air Conditioning; Streetcar and Trolley Coach Heating and Ventilating; Passenger Bus Air Conditioning; Automobile Air Conditioning; . Aircraft Air Conditioning; Ship Air Conditioning, Heating and Venti lating, Refrigeration Systems, Air Condition Space Treatment, . Systems and Controls THE principles of air conditioning applying to stores, restaurants, hos pitals, theaters, and homes are applicable to railway passenger cars, passenger buses, automobiles, streetcars, trolley coaches, airplanes and ships. However, equipment used for mobile applications differs from that used for stationary purposes in that it must meet additional requirements. Equipment must be compact, accessible for quick inspection and servicing, light-weight and unaffected by vibration and impact. Freedom from vi bration which could be transmitted to supporting vehicle and thus to pas sengers, is essential. RAILWAY PASSENGER CAR AIR CONDITIONING The railway passenger car represents a very 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 since servicing points are frequently far apart. During the heating season it is necessary to heat conventional cars with steam from the locomotive at pressures that may vary from 250 psig to only 5 or 10 psig on the last car in long trains. Passengers in window seats must sit only a few inches from cold outside walls and windows, and must also be very close to standing radiation installed along sides of cars. Sud den changes in load may be caused by changes in sun, wind, or train move ment. Even in coldest weather, outside doors must be opened frequently. During the cooling season, the problem is further complicated by a high concentrated internal load due to the passengers. Also, air distribution problems are increased by low ceilings and short air throws. Heating The heating of passenger cars is accomplished by using a split system consisting of an overhead air circulating system with heating and cooling coils, and standing radiation (floor heat) along car sides. The floor heaters, which usually consist of finned tubing, may be made more efficient by Usmg covers designed to increase gravity air circulation, and to direct the warm air from finned heating surface along cold outside walls and car MmWS' some new cars>wa^ convector panels are used and extend the jj length of the car, with air intakes along the floor and outlets at win now sill height and at window head height in dead-light panels. The heated Panel protects passengers from cold outside walls, and the chimney effect of panel duct increases air flow and improves heating surface efficiency, oteam may be used directly in finned tubing, or steam may be used to nea a liquid (usually a mixture of water and diethylene glycol) which is 1051 1052 CHAPTER 48 1954 Guide circulated through the finned tubing by means of circulators. If steam is used directly, it is difficult to distribute the heat uniformly along the length of the car. In the case of steam, it is. customary to divide lone finned tubes into separate sections which are fed independently. This is not true zoning since it' is not based on principles for zoning. (See Chapter 30.) The finned tubing at the floor must have sufficient capacity to offset ef fects of cold walls and windows during normal operation, and to heat the entire car to a minimum temperature of 60 F during standby when the over head system is not operating. The maximum capacity required (deter mined 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 capacity to heat the outside 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 capacity of the overhead heating coil is approxi mately 100,000 Btu based on 2400 cfm of circulated air, with 600 cfm of this being outside air for ventilation. ' All Btu figures are approximations of actual heating requirements, and do not include heat losses in the trainline (or leakage) or losses in the undercar piping. The heat losses in the under car piping can become a major portion of the train heating boiler load on cars having many undercar loops and steam regulating devices. Refrigeration . For cooling and dehumidification during summer, refrigeration may be obtained from ice bunkers, steam jet systems, or mechanical compressors (driven directly from car axle by electric motors or by gas engines). Re frigeration required varies with load conditions, but tons per car is one capacity frequently used. Evaporative type condensers are sometimes used in combination with the usual air condenser on either steam jet or mechanical refrigeration. When an electric motor (approx. 10 hp) is used to drive the air condi tioning 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 locomotive, and the power available for refrigeration, when train stopped at a station, is limited to storage batteries. One solution to this problem is to use a d-c generator driven by a gas engine. Another is to use a Diesel-driven alternator in a special head-end car to furnish power h> the entire train. Recently there have been installations in which a Dieseldriven alternator is mounted on an individual passenger car to supply Ike power requirements of the car. The attractiveness of this type of installa tion 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 pro vide hot water for wash rooms when outside temperatures are above ap proximately 30 F. This feature is important on trains using Diesel loco motives, since it eliminates the need for firing the steam heating boiler m the locomotive during a portion of the year. Air Distribution and Cleaning 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- Transportation Air Conditioning 1053 An average passenger car contains 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 dehumidification, but other constituents can be successfully handled only by proper ventilation and air cleansing. In an average car, from 2000 to 2500 cfm are circulated by the air conditioning unit. Some of this air may be recirculated, but a portion of it should always be brought in from outside. The amount of outside air desirable depends upon the type of car, number of passengers, air temperature, humidity, odors, and whether or not the occupants are smoking, and will vary from 15 to 90 percent of the total air circulated. Careful attention must be exercised in specifying the rate of outside air taken in so as to fit the type of service adequately, and yet not supply more ventilation than is necessary. Conditioning of this outside air is a major factor in determining size of both summer and winter equipment. For normal conditions, 10 cfm of outside air per passenger are provided. When smoking is permitted, at least 15 cfm should be admitted. In some dining cars, and deluxe sleeping cars, outside air rates as high as 20 to 30 cfm per occupant are used. A ceiling duct lengthwise along the 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. Outside 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 recently air- conditioned cars, there are no dampers or shutters at the outside air in takes; the percentage of the outside air is controlled by adjusting flow through the recirculating grille. . A considerable number of 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 outside 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 metal, wool, cloth, spun glass, hemp, paper, hair and wire screen. Most niters 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 precipitalon for air cleaning. In this system the coarser particles are removed 1054 CHAPTER 48 1954 Guide 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 impurities, thus reducing the amount of outside 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 automatically as required. When heating, it is important that floor-heat finned tubing be controlled at stable temperatures. Wide fluctuation in its temperature is highly ob jectionable because of location close to the passengers. Stable operation may be secured by controlling the floor heat on the basis of outside condi tions (see Chapter 30 on zoning), and using an overhead air circulating system to maintain final car temperatures. Because of window condensation and other problems, usually no attempt is 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 ordinarily provided for operating mechanical compressor systems at partial capacity. In this case split evaporators are used, so that evaporator surface and compressor capacity can be reduced together under light load conditions. Under very light cooling loads, the relative humidity in a car tends to increase because of long off periods of refrigeration equipment. This can be prevented by starting refrigeration equipment on low capacity at an established outdoor air temperature, operating it continuously, and using a heating coil in the overhead system to re-heat sufficiently to maintain de sired car temperatures. Under higher load conditions the heating coil becomes inoperative, and compressor and evaporator capacity are increased as needed. Room type sleeper cars introduce a further problem of providing indi vidual adjustment of room temperatures. Sometimes this individual control is secured by adjusting air volume, but such adjustment is unsatis factory for overall comfort, and may affect the air supply to other rooms. Another method is to use the heaters at the floor to control the room tem perature, but this tends to cause unstable and improper floor heat tempera tures which may be objectionable to the passengers. A simpler and basically more satisfactory system is to use a small booster heater m individual overhead air supply ducts to each room under manual control of the occupant. In this case, the floor heat and basic overhead systems are automatically adjusted for varying load conditions just as in a simple coach type car. A fixed amount of heat regulated by the occupant can be added by the room booster heater to maintain desired individual room temperature. Temperature lag is less when room boosters are used instead of gravity floor heating control. Any adjustment of the booster will g>ve the occupant immediate change in space conditions. The use of floor heat surfaces for room control may also cause low or excessive surface temper atures close to the passenger, with resulting discomfort. Transportation Air Conditioning 1055 STREETCAR AND TROLLEY COACH HEATING AND VENTILATING Streetcars and trolley coaches present a special problem in the main tenance of satisfactory comfort conditions because of the frequent opening of the doors and highly fluctuating passenger load. Space limitations for ducts, and a desire to keep outlet grilles well above the floor to facilitate car cleaning, add further problems to the distribution system. Maintain ing comfort conditions at the driver's station cannot be overlooked, since bis term of occupancy is considerably longer than that of any passenger, and because he is usually dressed more lightly than passengers. A separate source of heat is usually provided for the operator, and is under his control. Heating and Ventilating Recently-built streetcars and trolley coaches obtain heat from air blown over the main accelerating resistors and track switch resistors, to heat the passenger space. In the modern streamlined streetcars, designated P.C.C., approximately 2400 cfm are drawn from the car and blown over these re sistors to dissipate their heat. In trolley coaches, an amount of 800 cfm is customary. The heated air is then delivered to the passenger space or diverted to the outside by means of dampers, as required. If available heat from this source is insufficient, auxiliary electric heaters in the supply ducts may be cut in. The air distribution system is 100 percent recirculat ing when the maximum heating requirement is being met. At conditions other than maximum heating demand, part of the air drawn from the car is exhausted.to the atmosphere. Outside air enters the car, under these con ditions, by infiltration at all cracks and through doors when opened at stops. The most recently-built streetcars have added ventilating fans in the roof structure to introduce outside air through ceiling diffusing grilles. By governing the outside air volume introduced through these roof fans in coor dination with the heated air distributing system, it is possible to maintain a slight pressurization of the passenger space and avoid inrush of air when the doors are opened to load passengers. The roof fans also provide an effec tive means of maintaining lower inside temperature during summer opera tion. Ventilation tests on P.C.C. streetcars indicate that with 90 F outside temperature and above, 12,000 cfm are required to provide sufficient air change to keep inside temperature within a few degrees of outside air tem perature, and to provide enough air movement over passengers for comfort. H resu^s have been obtained by operating the ventilating fans and keeping the windows closed. New cars provided with adequate ven tilating capacity have been built with fixed sash. Control Temperature control, consisting of equipment especially designed to ithstand the vibration present on transportation equipment, is used, utomatically operated dampers are used to control flow of heated air to the finger space, or to direct heated air to the atmosphere. An automatth ^ Pcrated rheostat or multi-point switch is used to vary the speed of thp ven*'hating fans. Recent control system applications employ one Pera*'e both heating dampers and ventilating fans in a jje ,ulatlI?8 or graduated manner, with a compensating thermostat in the the SUPP y to correct for wide fluctuations in temperature of airleaving Ventilating fans are usually stopped or operated at lowest as th dunn6 ^he heating cycle, and then their speed is gradually increased ne car temperature rises above the heating-cycle control point. 1056 CHAPTER 48 1954 Guide- PASSENGER BUS AIR CONDITIONING rg 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 create this problem on urban vehicles. Provision of heat for the driver independent of the passenger heating system, is a further problem. The inter-urban bus, however, is usually a deluxe vehicle and may require a comfort cooling system. Space and weight limitations and vibration must be considered. Heating Recent designs of bus heating systems obtain improved 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 application similar to that in railway passenger cars. Forced air circulation over this finned floor heating surface has been provided to increase its effectiveness. Oil burning booster heaters have been applied to many Diesel-powered buses to raise the temperature of the engine coolant for maximum engine operating efficiency, and to provide sufficient heat for the passenger space. Ventilation Air for ventilation is usually brought into a bus at the front, and dis tributed throughout the length of the passenger space by a duct or ducts near the ceiling. Except for a few designs employing 100 percent outside air for heating, no heating of the ventilating air has been provided. One recently designed distribution system for an inter-urban bus provides for a fixed minimum of outside air, and is arranged to increase the percentage of outside air to 100 percent when the heating or cooling load diminishes. The distribution ducts and diversion damper arrangement of this system make available two supply ducts and one return duct for heating and for cooling, with a changeover to all three ducts to supply air during the inter mediate ventilating cycle. This system permits utilization of atmosphenc cooling and ventilation to the greatest degree when it can be most econom ically employed in the interval between the heating and cooling demand. Conventional throw-away type filters or renewable filters are used in intake air ducts for many vehicles. Electrostatic filters have been success fully used in some installations. The need for elimination of dirt is great, but the problem is complicated by space limitations and limited power. Refrigeration , Summer conditioning systems for inter-urban vehicles range in cooling capacity from 36,000 to 48,000 Btu per hour. Mechanical compression systems using refrigerants are used, and are powered by water-cooled gasoline engines of approximately 14 hp. Complete systems add from 800 to 1300 lb to weight of the coach. Some times an auxiliary generator driven by the refrigeration system engine i used and serves to help charge the bus battery, thereby offsetting power drain imposed by the ventilating blower. Belted reciprocating 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 re- Transportation Air Conditioning 1057 quire about 5000 cfm of outdoor air, and this is provided by either centrif ugal or propeller type fans belted or direct-driven by the air conditioning citrine. Preventing noise and vibration from affecting passengers is of vital importance. Installations must be made for quick daily engine servicing. In all cases fuel is obtained from the main bus tanks, and in some, the main engine cooling system cools the air conditioning engine; Control Automatic temperature control is receiving more, attention in the design of new vehicles. Some municipalities and states have enacted laws re quiring that buses operated on their streets and roads be so equipped. The simplest control systems for heating of urban buses consist of a single thermostat to start and stop the blower of the heater unit. Improved heating systems employ a thermostat to control liquid flow to the heater cores by means of modulating valves, in combination with a means of stop ping the heating blower when no heat is required. Heating and ventilating control is accomplished by controlling the volume of outside air, over and above the minimum required in accordance with the temperature in the passenger space, by means of automatic modulating dampers in the out side air intake, or by varying the speed of the ventilating air blowers. In a large proportion of inter-city buses equipped with mechanical re frigeration, a single thermostat is used to start and stop the cooling opera tion. This may be accomplished by automatically starting an engine- driven compressor on the cooling demand or by engaging a clutch to drive the compressor. Modulated or graduated control of engine-driven com pressors may be accomplished by automatic regulation of the engine throttle controlled from a thermostat in the passenger space. Complete control systems are available to coordinate operation of the heating, ventilating and cooling equipment from a single thermostat, with automatic change over from heating to ventilating to cooling. . AUTOMOBILE SUMMER AIR CONDITIONING Recently summer cooling has been applied to automobiles. The average present-day automobile with little insulation, large, single glazed window areas, and high infiltration and exfiltration losses, requires about 15,000 Btu per hour of cooling capacity. One system utilizes a reciprocating compressor belted from the main engine fan shaft, thus operating at varying speeds up to 3000 rpm. The resulting refrigeration capacity varies from about 6000 Btuh at idling speed, to 24,000 Btuh at maximum car speed. A dry air condenser is placed in front of the engine radiator, and the liquid and suction refrigerant lines run back under the car floor to the evaporator which is located in back of the rear seat. Conditioned air is delivered into the car just above the shelf near the back of the rear seat. A return grille !s provided under the rear seat, and the recirculated air is filtered. Outdoor air is provided by infiltration. Power for the air circulating blowers is obtained from the car storage battery. Equipment of this nature increases the car weight approximately 200 lb. AIRCRAFT AIR CONDITIONING In the space of a few years, heating, cooling and ventilating of airplanes as progressed from comparatively simple systems to highly complex anuti-purpose designs. The attendant control problem has become corospondingly complex. On older, non-pressurized planes, the heating sys- 1058 CHAPTER 48 1954 Goidif^ tem 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 bypass 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, with results which, while not satisfactory, were passable. As these planes cruised at less than 200 mph and normally operated at low altitudes, changes in outside air temperatures were generally gradual enough so that manual readjustment of controls could maintain reasonably comfortable cabin conditions. 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 heater, and use of larger and faster planes, use of manual controls became impracticable. The com bustion 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 since 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 dis charged 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 defrosting. The cabin is maintained at the desired temperature by means of an auto matic control which operates both heaters simultaneously. This control consists of two duct thermostats, one being mounted in the air inlet duct between the air scoop and the heaters so that it is affected by outside ambi ent temperatures, and the other being mounted , in the heater 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. Its theory of operation follows. As the outside temperature starts to drop, the outside air duct thermo stat decreases in resistance, unbalancing an electronic bridge. This un balance is amplified by vacuum tubes and causes a power tube to close a relay, turning on the combustion heaters. The resulting increase in tem perature is sensed by the warm air duct thermostat which increases in resistance, thus re-balancing 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 over-heating or under-heating and keep the discharge air from alternating between extreme cold and extreme heat. In a slightly more elaborate system, two combustion heaters supply plenum chamber which is maintained at a constant temperature. Air from the plenum chamber is then mixed with outside air to maintain desired cabin temperature. 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 proportions of heated and Transportation Air Conditioning 1059 outside air necessary to maintain desired cabin temperature. The same type of control system as previously described is used, except that an ampli fier operates a two-phase motor capable of positioning 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 heating, the control problem becomes more complex. On all of these airplanes, the heat of compression from cabin supercharger must be controlled, the. air cycle or expansion turbines must be turned on and also, the heat 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 eupercharged-air inter-cooler would be in full closed position, so that none of the heat of compression would be removed, and the air would by-pass the expansion turbine and its compressor and the secondary after cooler. An additional automatic controller would be operating 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 heat 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 outside ambient temperature rises so high that cooling is desired, the cabin supercharger intercooler would be opened wide. If further cool ing were required, the air would to 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 sufficient to maintain ventilation, and adjust ing the cabin-pressure relief valve setting, by means of a cabin pressure se lector, to maintain the desired cabin pressure. Limits on maximum inside to outside 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 extremely rigid. It is commonplace for ships of this type to experience changes in outside ambi ent 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 thermo- s(at and to vibration experienced on all airplanes. All modern controls use some type of bridge system with temperature sensitive resistors as easing 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 J'ses an electronic amplifier, which in turn controls a two-phase motor, or, nrough 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 air craft temperature controls, they must be able to operate under great ex- 1060 CHAPTER 48 1954 Guide tremes of temperature, pressure and humidity, and also withstand contin uous extreme vibration. Heaters should have, in addition to control from thermostats, suitable limit controls to prevent over-heatingdue 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, control response must be phenomenally fast. For example, 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 sensing of change and an extremely rapid control movement essential. Also, in airplanes operat ing at Mach numbers in excess of 0.7, the control must react to the large adiabatic temperature rises encountered. Some of these problems are so new that controls still have not been developed to meet all of the desired conditions. However, present studies being made by control manufac turers should result in developments of such controls in the near future. SHIP AIR CONDITIONING In air conditioning a ship, the designer is faced with all problems that would normally arise on shore installation plus additional factors. Mechanical ventilation is an absolute necessity for the comfort of passengers and ships' personnel, and for utility and preservation of cargo and stores. Ships are constructed with water-tight bulkheads dividing the vessel into several compartments. This complicates the running of duct work and results in a multiplicity of both supply and exhaust fans. Temperature and humidity requirements of various spaces aboard ship vary widely. Passenger staterooms and public spaces must have year-round air condiditioning with is also being applied more and more to the quarters of the officers and crew. Boiler rooms, galleys, 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 a 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 equipment 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 unlimited supply of low cost steam at suitable pressure, (3) limitations of available space and permissible weight. The problem of heat transfer and insulation must be given careful con sideration. The thermal conductivity of ship building material, suc"Jl steel, copper and brass, is many times the value of building material use ashore. The length of ducts between heat sources and fans necessitate extra duct insulation. Hull insulation must be of high quality, wit" Transportation Air Conditioning 1061 attention given to fireproofness, low density, low thermal conductivity, ruggedness, vermin resistance, 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 common. 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 diffi culty 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 Table 1. Design Conditions fob Ships Area Heat* ing Living Quarters. .. Public Spaces........ Naval Vessels........ F 0 0 +10 Outside Deszok Txmpezlatubbb Ventilating Cooling F 95 95 88(DB) 80(WB) F 95(DB) 80(WB) 95(DB) 80(WB) 88(DB) 80(WB) Inside Conditions DB & R.H. Effective Temp. F% 80 50 80 55 85 50 F 73-74 731-741 75-78 machinery spaces, is usually preheated to temperatures of 50 to 70 F. No recirculation is used in ventilation and heating systems, but a manual reduction (25 to 50 percent) of air quantity is made during the heating cycle. All heaters are automatically controlled, and preheaters are de signed and installed to minimize possibility of freezing of condensate. Preheaters are frequently located close to the outside air intake in order to conserve insulation and, for the same reason, zone reheaters are located close as possible to each zone. Where a reheater serves only one space, Jt is commonly located in the space. 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. , Because of many different requirements of various spaces aboard ship, some design temperatures and humidities are given in Table 1. The resulting quantities of air should be checked against typical heating and ventilation practices for ships.* Machinery Spaces h TKhtev.pnme PurP0Se of machinery space ventilation is to maintain a t mutable temperature for the operating personnel. It is more practicable unif86 co?^n0 * personnel at working areas than to attempt to obtain mrm ambient temperature. The permissible temperature rise (above 3^on an<* Heating of Maritime Commission Ships, by J. W. Marhert (Heating and Ventilating 1062 CHAPTER 48 outside) at working stations is usually 15 deg, while the overall temperature rise is usually between 30 and 50 deg. - These spaces must be exhausted adequately, preferably by mechanical means. Every attempt should be made to remove air at or close 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 openings 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 heating to about 50 F will be required. t f r Living Spaces The minimum quantity of ventilation air required for any sleeping or office space, including hospital space, should be that which will limit the temperature rise over the outside air to not more than 10 deg (a rise of 7 deg is more satisfactory), or a minimum of 30 cfm per person, whichever is the greater. 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 require ment applies to mechanical exhaust, although natural exhaust may be used where only a short run of duct exists. Heat should be furnished to maintain the following temperatures: Staterooms, Berthing, Messing and Office Spaces.......................... 70 F Working Spaces and Shops.................................................................. 60 F Hospital Spaces...................................................................................... 75 to 78 F Toilets, Washrooms, Showers and Baths Spaces for these purposes should be fitted with mechanical exhaust ven tilation for odor and steam removal. .Usually, the surrounding living or working spaces are exhausted through them. Air requirements on mer chant vessels are commonly estimated on the basis of a complete air change in 4 min. Where the available air is limited by outside air requirements of air conditioning systems, a lesser quantity (one change in 6 min) is used for private bathrooms. Heat is obtained by use of convector radiators which should maintain a temperature of 70 F. Galleys, Bakeries, Laundries, and Food Handling Spaces The problem of the ventilation of spaces fitted for cooking and food preparation is primarily one of heat and smoke or fume removal. Com plete mechanical exhaust is always provided, and the mechanical supply is made equivalent' to at least 50 percent of the exhaust. Sufficient natural supply to provide an indraft is required. The exhaust quantities should be predicated on restricing the ambient temperature rise to 15 deg above the outside summer design air conditions. The resulting quantity change the air in these spaces in about 23 sec to 1 min. All of the exhaust should be arranged to remove air from the space through hoods fitted over the heat producing equipment. The tempered mechanical supply should blow air directly on the personnel, but away from the equipment, to minimize interference with the flow of exhaust air to the hoods. The problem of ventilating laundries is somewhat similar to that for galleys. The exhaust should be about 20 percent greater than supply to insure air indraft. Supply air is generally heated to a temperature of frolD t ; Transportation Air Conditioning 1063 45 to 60 F. Ventilation should be sufficient to change the air in the spaces in 1 to 4 min. 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 sup ply and natural exhaust are usually used. However, where inflammable gases may exist, natural supply and mechanical exhaust are provided. Many ships are fitted with dehumidification 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 outside 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 dehumidification systems generally utilize silica gel or lithium chlo ride with inhibitor. (See Chapter 38). In most cases central drying equip ment 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 outside air when weather conditions are favorable. Recirculation and dehumidification are used only when neces sary, i.e., when the weather dew-point approaches or exceeds the temper ature in the hold. Two control stations are generally provided, one in machinery space and one in chart or wheelhouse. These stations are arranged so that either may change the cargo conditioning system controls from use of outside air to use of conditioned air. SHIP REFRIGERATION The kind of refrigeration equipment chosen for a particular vessel depends on the same factors which would govern selection on land. Small tonnage systems use reciprocating or radial-type compressors. Ships requiring in excess of approximately 125 tons of refrigeration generally j)se centrifugal compressors. Steam jet refrigeration has proven satis factory on several large foreign liners and is being seriously considered in this countiy for similar applications. The two essential prerequisites of the steam jet (low-cost steam and condenser cooling water) are available. The type of equipment used for the refrigerated cargo space will de termine the equipment to be used for air conditioning. This consideration can reduce materially the overall cost, because a stand-by unit is always provided for cargo refrigeration. AIR CONDITIONING SPACE TREATMENT FOR SHIPS The application of air conditioning to new American passenger ships is Ve 1 established. All passenger staterooms, except steerage and third 1064 CHAPTER 48 1954 Guide 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, depending on the particular trade. Theaters, lounges, smoking 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 portlights are usually 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 small 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. Finned-tube radiation running the full length of the glass area is commonly used for this purpose. Introduction of warm air at the sill, in lieu of direct radi ation, is also used. Systems serving most public spaces are designed to provide all outside 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 outside air all-year-round. The important problem in ship air conditioning concerns the treatment of the small spaces such as passenger staterooms, offices, and crew quarters. Low headroom, congested quarters, double berths, and unsymmetric arrangements make each space a problem in air distribution and treatment. The simplest system used for small spaces consists of a central filter bank, 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 provided to take care of variations in heating loads. The reheater steam valve is controlled by a sub-master thermostat at the reheater outlet. Control of room tem perature is obtained by operating manual dampers in the air supply to the space. A recirculation exhaust fan is frequently provided, and operates in conjunction with automatic dampers to utilize the maximum quantity of outside 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 pro vided with a control valve, controlled by room thermostat. Generally, 8 forced circulation single pipe hot water system is used. Fig. 1 shows a diagrammatic arrangement of this system. It should be noted that reheat is used to eliminate overcooling of the individual spaces during mild cooling conditions. This system is generally used for staterooms and small spaces devoted to first and second class passengers. The average total air per person is about 60 cfm, and average outside air per person is about 18 cfm- A third system, used to a limited extent, is similar to the system j051 described, except that each room is'provided with an induction unit type where possible) which reheats the primary air . supply. Control o> Transportation Air Conditioning 1065 Equipment and Individual Hot Wateb Room Reheatebs heating coil in the induction unit is the same as noted for the system de scribed in the previous paragraph. The average primary air supply is about 40 cfm per person. Recirculation is not always used. The amount of induced air varies with unit design. A fourth less common arrangement is similar, but makes use of hot water in the induction unit in winter and cold water in the induction unit in summer. Control of the valve on the unit is obtained by use of a summerwinter 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 passengers 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 outside master control. Relationship between subntaster and master control (wherein discharge temperature is raised as outdoor temperature drops), is set according to a schedule based on the ship's itinerary. Duct work for all systems described is designed for conventional velocity, owever, if power is available, and suitably strong duct construction and equate sound absorbing facilities are provided, high velocity systems may be used. BIBLIOGRAPHY Railway Passenger Cars ertorm&nce and Coat of Operation of 1937 Internal Combustion Engine Mechanical Compres- e*Qlionnf for Air Conditioning Railroad Passenger Cars, by Division of Equipment Research, Asscr n f American Railroads, Mayl?1937. 1066 CHAPTER 48 1954 Guide Report on Relative Performance of Air Filter*, by Mechanical Division, Association of Amen** o , roads, January 15. 1938. wrican uau- Air Conditioning of Railroad Passenger Cara, by L. W. Wallace and G. G. Early Jr IA S u ;? * actions, November, 1937). *' ' * '*>* 83 anTSareh ^936Cli16l)Methods' by Kenneth Cartwriht (Rofritorating Engineering. February, p p 1^ Dr`Ve f" ^aasenger Air Conditioning, by J. K. Hornaday (Refrigerating Engineering, March, !2 .. Rf^pad A*r Conditioning, by Gordon T. Wilson (Refricerating Engineering, May: 1943. n. 323} p,n~_ Air Conditioning, by M. R. Eastin (Railway Elec. Engr., August-December, 1942). * Head-End Power for Railway Cars, by F. L. Sahlmann and E. M. Bill (Railway Elec. Engr. Mav imm Hgd-End Power for Streamlined Passenger Trains, by J. D. Loftis (A.S.M.E. Raleigh Section, October ' P.C.C. Car Ventilation, B-3697 Westinghouse Electric Corp,, September, 1940. * Muses and Automobiles Bus Heating, by E. T. Todd and F. 0. Gadd (Heating and Ventilating, Dec. 1946 p. 83). iomn/- ofr>Auj9"ol?aes and Busea, by L. W. Child (Society of Automotive Engineers Journal -.v198S* Conditioning, by Jerry Hicke (Heating, Piping and Air Conditioning, October 19M 19393p 2SS)3 Alr Condltw*un*. by A- Malhnckrodt and Lara Hanson (Refrigerating Engineering, June, nal^July6TM39) ^ Conditionins Automobiles, by F. J. Linsenmeyej (Society of Automotive Engineers Jout- Airplanes Comfort in High Altitude Flying, by D. W. Tomlinson (A.S.H.V.E. Tbansactions, Vol. 47,1941 o 571 Heat Exchangers for Aircraft, by Arthur J. Hess (Refrigerating Engineering, September. 1944 d 192) ' Heat, mg and Ventilating for Transport Airplanes, by B. M. Brod (A.S.H.V.E. Transactions. Vol. 52, 1946) Com- formation of Aircraft, by Albert A. Arahym (Pitman Publishing Corp., New York 1945) Refrigeration for Air Conditioning Pressurised Transport Aircraft, by B. L. Messinger (Heating and Very tilating, January, 1946, p. 63). . . Ships British VOrtibe1r0ni939S)h'P3' by R` MoDtmald <-Jumat o/U, Imiilulion ot Heating and Ventilating Engineeri, VentilatioD 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). .Heating, Ventilating and Air Conditioning on Shipboard, by J. H. Clarke (Healing, Piping and Air Con ditioning, Auguat, p. 467; September, p. 529; October, p. 610 1940). Care of Cargo at Sea, by O. D. Colvin. W. H, E. Habne, and M. R. Colby (Traneaetieme of the Soeietg of Hanoi Arnhrtectsand.ManneEngtneere, Part I, Vol. 46. 1938. p. 109; PartII, Vol. 49, 1941, p. 208). j * Ships* by J. Dawson (Journal of The Institution of Heating arid Ventilating Engineers, Lon don Vol. 10, June-July, 1942. No. Ill, p. 89). Modern Marine Engineers Manual, Vol. II, Sections 16 to 19, Inc. (Cornell Maritime Press. 1943). Warship Ventilating, Heating and Air Conditioning, by Comdr. T. H. Urdahl, U.S.N.R., and W. C., Whittlesey (A.S.H.VJb. Transactions, Vol. 49, 1943, p. 35). Standardized Heating and Ventilating Equipment for Fighting Ships, by Comdr. T. H. Urdahl, U-S.NJL and Lt. John Everetts, Jr.. U.S.N.R. (Heating, Piping and Air Conditioning, July, 1943, p. 333). Designing Warship Ventilation with Standardized Equipment, by Comdr. T. H. Urdahl. U.S.N.R. and W. C. Whittle sey (Heating, Piping and Air Conditioning, August, 1943, p. 419). Ventilation and Heating of Maritime Commission Ships, byJ. W. Marked (Heating and Ventilating,Feb ruary, 1943, p. 32). Why Ship Ventilation, by J. W. Marked (Heating and Ventilating, October, 1943). Evo lution of Ships Ventilation Systems, by J. W. Marked ( The Log, 1944 Yearbook, p. 202). Refrigeration. Air Conditioning, Ventilation and Heating, by H. E- Parker (Marine Engineering, Vol. II, The Society of Nasal Architects and Marine Engineers, 1944, Chapter VI, p. 319). Blackout at Sea. by J. W. Marked (Heating and Ventilating, March, 1944, p. 55). Your Merchant Marine Will be Comfort Air Conditioned, by J* W* Marked (Heating and Ventilating, May, 1945, p. 60). ,?Sdern Air Conditioning, by J. W. Marked (MarineEngineering and Shipping Review, November, 1945, p, 177). # - Modern Marine Refrigeration andAir Conditioning, by W. H. Carrier and L. E. Starr (Marins Engineering and Shipping Review, April, 1946, p. 132). Dehumidification Protects U. S. Navy's Inactive Fleet, by Capt. T. H. Urdahl and Comdr. E. R. Queer, (Heating, Piping and Air Conditioning, March, 1946, p. 71). ' Reconversion of Liner S. S. Lurline, by Robed Tate (Society of Naval Architects and Marine Engineer*, May 12, 1949). 1946)ir CoQditioning of P~2 American President Liners, by J. W. Marked (Pacific Marine Review, August, Export Lines Air Conditioning of Four Aces, by J. W. Marked (Marine Engineering, March, 1949). CHAPTER 49 WATER SERVICES Sizing Cold Water Supply Piping, Procedure for Sizing Cold Water Systems, Cool ing Water Piping, Estimating Heating Load and Storage Capacity, Methods a of Heating Water, Computing Heat Transfer Surface, Hot Water Supply Piping, Control of Service Water Temperature, Safety Devices, Solar Water Heaters, Domestic Hot Water by Heat Pump PROPER design of the water distributing system in a building is neces sary in order that the various fixtures may function properly. The amount of either hot or cold water used in any building is variable, de pending on the type of structure, usage, occupancy, and time of day. It is necessary to provide piping, water heating, and storage facilities of sufficient capacity to meet the peak demand without wasteful excess in either piping or equivalent cost. SIZING COLD WATER SUPPLY PIPING 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 flow 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 deter mined exactly and is not readily standardized. The two main problems to be considered are: (1) the satisfactoiy 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 consumer depends greatly on the consumer, his standard of living, his professional needs, size of family, garden requirements, and similar factors. Depending on these factors, the per capita water consumption for domestic use usually varies between 20 and 80 gal per day. Experience indicates that the type f dwelling also has considerable influence on the water consumption. In apartment houses the per capita daily water consumption is generally ngher than in single-family houses. This is due to the use of a central metering system which is not conducive 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 apart ment houses, a daily per capita water consumption of 50 gal may be con tacted a safe design figure. Although a considerable number of housing projects have been developed throughout the United States, conclusive water consumption data have not yet been gathered. Nevertheless, it seems that the daily per capita water oonsumption in housing projects falls in between the consumption in apart ment houses and that in single dwellings at the same geographical location. 1067 1068 CHAPTER 49 1954 Guide Table 1. Proper Flow and Pressure Required During Flow for Different Fixtures Fixture Flow Pressure^ Flow gpm Ordinary basin faucet............................................................... Self-closing basin faucet......................................................... Bathtub faucet........................................... ................... Shower....;................................................. ......... '.......... Ball-cock for closet.................................................................. Garden hose, 50 ft, and sill cock............................................ 8 12 10 5 5 5 12 15 10-20 15 30 3.0 2.5 4.5 . 4.5 6.0 5.0 5.0 3.0 ls-to* 15.0 5.0 * Flow pressure is the pressure in the pipe at the entrance to the particular fixture considered. b Wide ranee due to variation in design and type of flush-valve closets. In general, a daily per capita water consumption 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 types of fixtures, and the average pressure necessary to give this rate of flow. The pressure necessarily varies with fixture design; with some, a much greater pressure is necessary to give the same rate of flow than with others. In general, the lower the quality of the faucet the greater will be the pressure required. In estimating the load, the rate of flow is frequently computed in fixture units. One fixture unit is equivalent to 7.5 gal per min. Table 2 gives the demand weights in terms of fixture units for different plumbing fix tures under several conditions of service, and Fig. 1 gives the estimated demand in gallons per minute corresponding to any total number of fix ture units. Fig. 2 shows an enlargement of Fig. 1 for a range up to 250 fixture units. . Table 2. Demand Weights of Fixtures in Fixture Units* Fixture ob Group* Occupancy Type op Supply Control Weight m "Fixture Units* _ Pnhl.V 10 5 10 6 3 2 4 4 3 4 6 3 1 2 2 8 6 2 2 3 3 --- * For Bupply outlets likely to impose continuous demands, estimate continuous supply separately and add to total demand for fixtures. . ia b For fixtures not listed; weights may be assumed by comparing the fixture to a listed one using water u* similar quantities and at similar rates. .. The given weights are for total demand. For fixtures with both hot and cold water supplies, the weigh for maximum separate demands may be taken as % the listed demand for the supply. Water Services 1069 No. 1 for system predominantly for flush valves. No. 2 for system predominantly for flush tanks. Fig. 1. Estimate Curves for Demand Load The estimated demand load for fixtures used intermittently on any supply pipe will be obtained by multiplying the number 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 outlets other than those listed in the table of fixture units is not yet in cluded in the estimate. The demands for outlets (such as hose connec tions, air conditioning apparatus, etc.) which are likely to impose con tinuous demand during times of heavy use of the weighted fixtures, should be estimated separately and added to the demand for fixtures used in termittently, in order to estimate the total demand. So far, the information presented makes possible the determination of the design rate of flow in any particular section of piping. The next general step is to determine the size of piping. As water flows through a pipe, the pressure continually decreases along the pipe, due to loss of energy from friction. The problem is then one of ascertaining the minimum pressure in the street main, and the minimum FIXTURE UNITS Fig. 2. Section of Fig. 1 on Enlarged Scale 1070 CHAPTER 49 1954 Guide! FRICTION LOSS IN HEAD IN LBS. PER SQ. IN. PER 100 FT. LENGTH Water Services FRICTION LOSS IN HEAD IN LBS. PER SQ. IN. PER 100 FT LENGTH 1071 Fig. 3. Flow Chart fob Copper Tubing 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 differential thus obtained will be available for overcoming pressure losses in the distributing system, and in over coming the difference 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 highest fixture, may be ob tained by multiplying the difference in elevation in feet by the conversion factor 0.43. When water flows through a pipe, friction occurs as the result of the sliding of water particles past one another. If the pipe wall is'rough, the roughness projections cause additional friction, owing to the develop ment of increased turbulence in the flowing water. As the water flows along a uniform pipe, the pressure decreases as a result of a dissipation of Fig. 4. Flow Chart for Fairly Rough Pipe 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, and roughness of pipe. 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 aopper, brass, or lead may usually be classified as smooth. fairly Rough. All ordinary pipes, such as wrought iron, galvanized 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 after "in6 laid, are classified as rough. Pigs. 3, 4 and 5 give the pipe friction losses corresponding to these three types of pipes for various nominal diameters.1 Example 1: A 2i in. fairly rough pipe supplies 100 gpm of water. Find the fric tion loss in head if the pipe length is 200 ft. 1072 CHAPTER 49 FRICTION LOSS IN HEAD IN LBS. PER SQ. IN. PER 100 FT. LENGTH Water Services 1073 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 been found, for example, that a 1 in., 90 deg elbow introduces a loss equivalent to.2.2 ft of straight 1 in. pipe. Therefore, for each 1 in., 90 deg elbow, 2.2 ft of 1 in. pipe are added to the total length of 1 in. pipe. , Estimated pressure losses for pipe fittings and valves in terms of equiva lent pipe length are shown in Table 4. . Table 5 lists the equivalent lengths for various special types of ap paratus 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. Fig. 5. Flow Chart for Rodgh Pipe Solution: Enter Fig. 4 at 100 gpm, and move along this line until it intersects the 21 in. diameter line. From this intersection 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 4.5 = 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. Estimated pressure losses for disc-type meters for various rates of flow are given in Fig. 6. Flow limits for disc-type meters, which may be regarded as the limits of recommended ranges in capacities, are given in Table 3. For informa tion on other types of meters, the manufacturers should be consulted. 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 Stale University of Iowa. The loss of pressure through any fitting or valve can be expressed iu Tig. 7. Variation of Pressure Loss with Rate of Flow for Various Faucets and Cocks a. ) in. laundry bibb (old style). E. Combination compression sink faucet Laundry compression faucet. F. Basin faucet. I in. compression sink faucet (Mfr. 1). G. Spring self-closing faucet. ^-2. 4 in. compression sink faucet (Mfr. 2). H. Slow self-closing faucet. Combination compression bath tub faucets (both open). (Dashed lines indicate recommended extrapolation) 1074 , . CHAPTER 49 Table 3. Performance Requirements of Water Meters* Sizs In. . 3 1 IU 9. a A R. ' Normal Test-Flow Limits GPM 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 Minimum Test-Flow GPM 1 2 4 7 12. * American Water Works Association Standards: ' Registration. The registration on the meter dial hall indicate the quantity recorded to be not less tw 98 percent nor more than 103 percent of the water actually passed through the meter while it is being tested at rates of flow within the specified limits herein under normal test flow Limits: There be not less 90 percent of the actual flow recorded when a test is made at the rate of flow set forth under minimum test The water demand for hose bibbs or other large demand 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 possible) 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 exces sive 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-feed systems are the same. The principal difference in procedure is that in the downfeed 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 fol lowing 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 flow of each fixture. . Table 4. Allowance in Equivalent Length of Pipe for Friction Loss in Valves and Threaded Fittings Diameter of Fitting In. 90 Deg Standard Ell Ft %---------------------14----------------% l ___ , m----------------2 2)43 m---------------------- 4 5 ______________ i 2 2.5 3 4 5 7 8 10 12 14 17 20 Equivalent Length of Pipe for Various Fittings 45 Deg Standard Ell Ft 0.6 1.2 1.5 1.8 2.4 3 4 5 6 7 8 10 12 90 Deg Side Tee Ft Coupling or Straight Run of Tee Ft 1.5 3 4 5 6 7 10 12 15 18 21 25 30 0.3 0.6 0.8 0.9 1.2 1.5 2 2.5 3 3.6 4.0 5 6 Gate Valve -Ft 0.2 0.4 0.5 0.6 0.8 1.0 1.3 L6 2 2.4 2.7 3.3 4 Globe Valve Ft 8 15 20 25 35 45 55 65 80 100 125 140 165 Angle Valve Ft 4 8 12 15 18 22 28 34 40 50 55 70 80 ----- Water Services 1075 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. 1 or Fig. 2, find the expected demand in gallons per minute. 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 and 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 psi. 6. Calculate, by means of Equation 1, the approximate design value of the average pressure drop per 100 ft of pipe in the equivalent length determined in paragraph 4. inn p = IP - 0.43// - 10] ~ where . p -- average pressure loss per 100 ft of equivalent length of pipe, psi. P = pressure in street main, psig. (1) Table 5. Equivalent Lengths of Iron Pipe to Give Same Loss as Special Fittings and Apparatus Fitting Apparatus 30-gal Vertical hot-water tank, ^ in. pipe. . . 30-gal Horizontal hot-water tank, a in. pipe.. Water meters (No valves included) . H in. with % in. connections......................... % in. with % in. connections......................... 4 in. with in. connections......................... 1 in. with I in. connections. ........................... 1)4 in. with 1 in. connections......................... Water softener........................................................ Nominal Diameteb of Pipe--Inches H M 1 1M 4 17 56 1.2 5 16 ___ -- 6.7 28 90 4.8 20 64 3.4 14 45 -- 9 30 -- 4.4 14 50-200 -- ___ -- -- 115 54 -- 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 m the tank, converted to pounds per square inch by multiplying by 0.43, replaces the street main pressure, ana the term 0.43 H in Equation 1 is added instead of sub tracted in calculating the term p. In this case, H will be the vertical distance of the fixture below the bottom of the tank. 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 2: Assume a minimum street main pressure of 55 psig; a height of topmost fixture above street main of 50 ft; 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 the water closets are flush-valve operated. Find the required size of supply main. volution: From Fig. 2 the estimated peak demand is found to be 51 gpm. From -lable 3 it is evident that several sizes of meters would adequately measure this flow. *'or a trial computation choose the 1)4 in- meter. From Fig. 6 the pressure drop fimugh a 1^ in. disc-type meter for a flow of 51 gpm is found to be 6.5 psi. -j. Then the pressure drop available for overcoming friction in pipes and fittings is 05 ~ (15 -f 50 X 0.43 -1- 6.5) = 12 psi. of tins point it is necessary to make some estimate of the equivalent pipe length 1 the fittings on the direct line from the street main to the highest fixture. The *act equivalent length of the various fittings cannot now be determined since the P*Pe sizes of the building main, riser, and branch leading to the highest fixture are not fiown as yet, but a first approximation is necessary in order to make a tentative ejection of pijje sizes. If the computed pipe sizes differ from those used in determing the equivalent length of pipe fittings, a recalculation will be necessary, using 1076 i CHAPTER 49 1954 Guide Table 6. Computation of Branch Size in Example 2 Fixtures No. and Kind Fixture Units (From Table 2 and Note c) --..._ Demand (From Fig. 2) Gpm Pipe Sub (From Fig. 4) Jjf. 3x6 =18 f (2 x 2) = 3 1 (3 x 1) - 2.25 23.25 38 il the computed pipe sizes for the fittings. For the purposes of this example assume that the total equivalent length of the pipe fittings is 50 ft. Then the permissible pressure Iobs per 100 ft of equivalent pipe is 12 X 100/(100 + 50) = 8 psi. Assuming that the corrosive and caking properties of the water are such that Fig. 4 for fairly rough pipe is applicable, a 2 in. building main will be adequate. The sizing of the branches of the building main, the risers, and fixture branches follow the principles outlined. For example, assume that one of the branches of the building main carries the cold water supply for 3 water closets, 2 bath tubs, and 3 lavatories. Using the permissible pressure loss of 8 psi per 100 ft, the size of branch determined from Table 2 and Figs. 1 and 4 is found to be 1) in. Items entering the computation of pipe size are given in Table 6. COOLING WATER PIPING Water is very frequently used in refrigeration systems, cooling towers and other similar installations. In designing the piping system of such installations, the principles of hydraulics, as already outlined, are em ployed. Nevertheless, there are several practical items having particular application to cooling installations. They are outlined in the following paragraphs, and it is important that the designer be familiar with them. In choosing pipe material, the problem of corrosion should be kept in mind to prevent defects in the system. If the water does not have drastic corrosion characteristics, wrought iron or steel piping may be used; other wise, galvanized steel piping may be preferred. 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, iron pipe is commonly employed. In regard to assembly, cast-iron flanges or welded joints are to be pre ferred to screwed joints wherever possible. Valves used in circulating systems may be of the globe, gate, or angle Table 7. Pipe Sizes for Cooling Towers* Rated Tons of Refriq. Cooling Water GPM Pipe Sizes (No minal Inches) Inlet to Tower Outlet from Tower 3 to 5 7 to 15 20 25 35 50 10 to 18 20 to 45 65 86 . 115 170 li 2 21 21 3 3 H 2 3 4 4 4 75 225 100 300 150 450 200 600 250 750 5 5 5 6 8 6 6 8 8 8 Water Services 1077 types. If water is the circulating medium, brass, valves are usually used. However, if the circulating medium is an electrolyte, such as brine, then it is preferable to use valves made of the same material as the piping itself. The friction loss in the piping may be determined from Fig. 4 for fairly rough pipe. If the coolant is brine, a correction for the proper density must be made. Experience indicates that in sizing piping for cooling sys tems, 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. 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 tempera- Table 8. Maximum Daily (24-Hr) Requirements fob Hot Water in Gallons Apartments and Private Homes No. or Rooms 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Number of Bathrooms 1 60 70 80 . 90 100 120 140 160 180 200 -- --. -- -- -- -- -- -- -- -- 2 __ __ __ 120 140 160 180 200 220 240 260 . 280 300 -- --. -- -- -- -- -- 3 __ __ -__ __ 200 220 240 260 280 300 325 350 375 400 __ -- __ __ -- 4 __ -- -- -- -- -- -- 250 ' 275 300 340 380 420 460 500 540 580 620 -- -- 5. , -- __ .-- -- -- -- -- -- -- -- 450 500 550 600 650 700 750 800 850 Hotels Room with basin............................................................................................................... 10 Room with bath--transient............................................................................................ 50 Room with bath--resident.............................................................................................. 60 2 Rooms with bath........................................................................................................... 50 3 Rooms with bath........................................................................................................ 100 Public shower................................................................................................................. 200 Publio basins........................................................ 160 Slop 8 ink.................................................................................. Office Buildings Hojpilali White collar worker (per person)............................................................................... 2.0 Other workers (per person).......................................................................................... 4.0 Cleaning per 10,000 sq ft.................................................. ........................................... 30.0 |per bed ................................................................................................................... 80-100 hire of about 76 F. Table 7 gives pipe sizes frequently used for various sizes of cooling towers, assuming a hot-water temperature of 95 F and a cold-water temperature of 85 F.2 ESTIMATING HEATING LOAD AND STORAGE CAPACITY The maximum daily and the maximum hourly hot water demand form the basis for the selection of the heater and the storage tank. In general, two thirds of the total daily water consumption is hot water. I or residential dwellings, a design value of about 20 to 30 gal per capita Per 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 30 1078 CHAPTER 49 I' 1954 GuiSf any house or apartment. Table 8 gives estimates of the maximum hot' water requirements in 24 hr in various types of buildings. 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 reasonably uniform, as in residences, apartment buildings, hotels, and the like, smaller storage capacity is required than in the case of factories, schools and office build ings, where practically the entire day's usage of hot water occurs during a very short period. Correspondingly, the heating capacity must be pro portionately greater with uniform usage of hot water than with inter mittent usage, where there may be several hours between peak demands during which the water in the storage tank can be brought up to tempera- Table 9. Estimated Hot Water Demand Characteristics for Various Types op Buildings Type of Building Hot Water Required Max. Hourly Dehand in Relation to Day's Use Duration of Peak Load Hours Storage Capacity in Relation to Day's Use Heating Capacity in Relation to Day's Use Residences, Apartments, 40 gal per hotels, etc. person per day* Office buildings - 2 gal per person per day* Factory buildings 5 gal per person per day* 1/7 1/5 1/3 4 1/5 2 1/5 1 2/5 1/7 1/6 1/8 Restaurants Restaurants 3 meals per day Restaurants 1 meal per day 1/10 1/10 8 1/5 1/5 2 2/5 1/10 1/10 1/6 At noF ture. As a general 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 heating 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 has 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 domestic hot water, the computed load on the boiler should be increased by 4 sq ft EDR (equiva lent 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 watei requirements of a building: (1) by the number of people, and (2) by the number of plumbing fixtures installed. Where the number of people to be served can be reasonably estimated, the data in Table 9 may be used. Example 3: Determine the heater size and storage tank capacity for a residence housing five people. Solution: From Table 9, a residence housing five people would have a daily rB" Water Services 1079 miirement of 5 X 40 = 200 gal. per day, and a maximum hourly demand of 200 X 1/7 6= 28.5 gal. The heater should have a storage capacity of 200 X 1/5 -- 40 gal, and a i. .-* ________ :a.. rnri i m __ OQ K ol nov hr . The conditions given in Example 8 may be cited as average. It is pos able to vary the storage and heating capacity by increasing and decreasing one over the other. Such a' condition is illustrated in Example 4- Example 4: Determine the required heater capacity for an apartment housing 200 people, if the storage tank has a capacity 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. 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. W ater 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 tank had been installed, the required heat i.ng capac.ity per .hour wou,ld. .be4--5-6--0-'-------(-2--50-0-- X----0--.-7-5--) -- o/i gai. Table 10 may be used to determine the size of water heating equipment from the number of fixtures. To obtain the probable maximum d&mand, 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 this probable 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 tank size for an apartment build ing from number of fixtures. 60 lavatories :.................................................................... X 2 = 120 galperhr 30 bathtubs........................................................................ X 20 = 600 galperhr 30 showers........................................................... X75=2250 galperhr 60 kitchen sinks................................................................ X 10 = 600 galperhr 15 laundry tubs................................................................ X 20 = 300 galperhr Possible maximum demand.......................................... = 3870 gal per hr Probable maximum demand....................... -- 3870 X 0.30 = 1161 gal per hr Heater or coil capacity.................................................. = H1 gfll Per hr Storage tank capacity.................................. = 1161 X 1.25 = 1450 gal Although, in private dwellings a water temperature of 140 F is reason able 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. Tbe 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 restau rants) to determine the total number of dishes per day. 2. Divide the total number of dishes per day, as determined by method in para graph 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 gallons of 180 F water (using 1.5 for single tank machines and 0.75 for two tank machines). This product will give the gallons of 180 F water per day for rinse sprays. 4. Multiply the Dumber of meal periods per day (one, two or three) by the dish- f i . '* . ii| ! : l'\ ! ,! : ;| li*.\ '' !j| . [j ] j y washing tank capacity in gallons, giving the gallons of 180 F water per day necessary to fill the tanks. 5. Add vahies from paragraphs 3 and 4 to obtain the total number of gallons of 180 x* 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 res taurant, multiply the total number 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 1.2 and 1.5 gal per meal, respectively.8 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 Table 10. Hot Wateh Demand per Fixtures for Various Types of Buildings Gallons of water per hour per fixture, calculated at a final temperature of HOF Apart ment House Club Gym nasium Hos pital Hotel Indus trial Plant Office Build ing Pri vate Resi dence School Y.M. CA. 1. Basins, private lavatory 2 2 2 2 2 2 2. Basins, public lavatory 4 6 . . 8 . 6 8 12 3. Bathtubs........................ 20 20 30 20 20 30 4. Dishwashers.............. 15 50-150 50-150 50-200 20-100 5. Foot basins.................... 3 3 12 3 3 12 6. Kitchen sink................. 10 20 20 20 20 7. Laundry, stationary tubs............................. 20 28 28 28 8. Pantry sink................... 5 10 10 10 9. Showers.......................... 75 150 225 75 75 225 10. Slop sink........................ 20 20 20 30 20 11. Demand factor............. 0.30 0.30 0.40 0.25 0.25 0.40 12. Storage capacity factor4 1.25 0.90 1.00 0.60 0.80 1.00 2 6 15 0.30 2.00 2 22 15 8 20 30 15 20-100 20-100 3 3 12 10 10 20 20 5 75 15 0.30 0.70 10 225 20 0.40 1.00 28 10 225 20 0.40 1.00 * Ratio of storage tank capacity to probable maximum demand per hour. surfaces. The simplest method is to have the fire on one side 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 re sultant 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 perature at which the lime, magnesia, etc., collect on hot surfaces, varies with the character and proportions of the solids, but generally such deposits are not a serious trouble below 140 F. Coal-burning, direct-fired water heaters may be constructed of cored cast-iron sections, or of steel. In some cases the external appearance of the cast-iron sections is the same as in heating boilers, but internally the cores are changed to enable the sections to withstand the city water pres sure. In small capacity water heaters, efficiency is not considered so important as low fust cost and ability to maintain a fire at a low rate of combustion, and consequently, such heaters are generally built with a dry Water Services 1081 section or fire-brick fining at the base of the fire-pot to prevent too much chilling of the fuel. While mud and scale will eventually clog the water ways of any direct-fired heater, increased fife may be obtained by pro viding 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. Clean-out openings in the bottom of the heater are advantageous, if used by operators of water heaters for periodic cleaning out of sediment. Oil-burning, direct-fired water heaters usually are of steel, and operate with higher flame temperature and better efficiency 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 heaters 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 Fig. 8. Indirect Water Heater 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 water heaters are an important consideration. Refer to Chapter 17. Electric water heaters for domestic hot water supply are described in the section Heating Domestic Water by Electricity in Chapter 42. 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 fhe outside of the steam tubes which are submerged within a tank. A typical indirect heater using steam is shown in Fig. 8. The coils usually |P'e of copper, 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 fining, or may be of copper or copper alloy. Where straight heating tubes are used, one end of the tube is usually expanded into a floating head to take care of expansion. The coils should be capable of . j.l .1. w . ji'jf hot wafer to fixtures Fig. 9. Indirect Water Heater Mounted on Side of Boiler easy withdrawal for inspection and for removal of scale. Instead of steam, the heating medium may also be hot water inside the tubes. Another method of transferring heat from a heating boiler to the domestic water is illustrated in Fig. 9. The water heater is generally a cast-iron shell within which there is located a spiral copper coil. Hot water from the boiler circulates inside the shell and 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 bottom of the tank as far above the boiler as possible. Horizontal storage tanks of less than 18 or 20 in. diameter are not recommended because of the difficulty of preventing the hot and cold water from mixing, and especially is this an important consideration when large quantities of water are withdrawn. In Fig. 10 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. 9. 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 sur face is in the form of a number of straight copper tubes, with rear U-bends or a floating head, inserted through a special opening in the boiler. While the coil may be placed in the steam space above the water line of a steam boiler, it is usually placed below the water line. Long coils of small diam eter 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 desired temperature in one passage through the coil. This arrangement is fre quently 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 uniform 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 domestic 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 domestic 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 effect of impurities and means of improving the quality of the water are important items, as brought out in Chapter 43. COMPUTING HEAT TRANSFER SURFACE The area of the inside surface of a heating coil may be determined from Equation 2. where Q X 8.33(1, - fi) Ux tm (2) A -- surface area of coil, square feet. Q = quantity of water heated, gallons per hour. ' U = hot water outlet temperature, Fahrenheit. fi = cold water inlet temperature, Fahrenheit. . U = coefficient of heat transmission, Btu per (hour) (square foot) (Fahrenheit de gree logarithmic mean temperature difference). For copper or brass coils U -- 240 (steam) and 100 (hot water). For iron coils XJ = 160 (steam) and 67 (hot water). = logarithmic mean of the difference between the temperature of the heating medium and the average water-temperature, and is approximately: -[H*] -- temperature of the heating medium, Fahrenheit. Equation 2 may be used to check the heating coil ratings under tempera tures other than those stated in the manufacturer's published ratings. Example 6: What area of copper transfer surface will be required to heat 70 gal water per hour from 40 to 180 F with boiler water at 220 F? Solution: Fig. 10. Indirect Water Heater Placed in Boiler ^220 70 X 8.33(180 - 40) 110 A = = 7.42 sq ft 100 X 110 u For>tantaneous submerged heaters, the surface required will depend tun i YeIocity f water in the tubes, (2) the boiler water tempera- /.,e; 0) the inlet water temperature, (4) the outlet water temperature, 1 ) the cleanliness of the coil surface, and (6) the condition of the boiler ater surrounding the coil. If the heater is located in the water of an ac- Mi*. 1084 CHAPTER 49 1954 Guide tively steaming part of a boiler, the heat transfer may be twice as great as would be obtained if the water surrounding the coil were circulating slowly. Ratings of instantaneous water heating coils will therefore vary greatly, depending upon the assumptions made .regarding the conditions of operation. The. .values of the coefficient of heat transmission for in stantaneous heaters, shown in Table 11, are conservative. . For a coil in which heat is transferred from steam to water, the value of U = 300 V~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 the carrier and the water which receives the heat. For this reason, where the transfer occurs from heating system water to domestic water, it is good practice to install a circulating pump to insure rapid movement of the boiler water. In view of the high condensation rates obtained when steam is used with gravity circulation from the boiler, as when there is a sudden demand followed by an inflow of cold water, the bottom of a steam heating 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, Table 11. Coefficient of Heat Transfer of Instantaneous Water Heaters U -- Btu per {hr) (sg ft) {Fahrenheit degree logarithmic mean temperature difference) Boiler water temperature..................... v.................................................. .... 210 225 200 175 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 sections, there should be a sepa rate tapping for water circulation into every section of the boiler, as shown in Fig. 9, unless the boiler has large top nipple ports providing inter-sec 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 the heater and, further, the unconnected sections will not deliver any heat to the water heater. 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, m which the piping from the heater to the 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 downfeed piping system. Three common methods of arranging the circulating lines are shown in Fig. 11. Although the diagrams apply to multi-story buildings, the arrangements (a) and (b) are sometimes used in residential designs. A check valve should be provided in the run-out from each return riser to prevent temporary reversal of flow in the piping when a faucet is open. Proper air venting of a circulating system is extremely important, particu larly if gravity circulation is employed. In Fig. 11 (a) and (6), this is ac- Water Services 1085 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 the highest fixture as in Fig. 11 (c), an automatic float type air vent is installed at the highest point of the system, ora 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 pressure 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 sizing of the hot water supply pipes are the same as those for the sizing of cold water supply lines. For small and medium sized installations a %-in. hot water return will be ample. For larger installations, the size of the hot water return may be computed from considerations of the heat losses in the hot water piping.4 A throttling -> P* __ ^ Vent 1 t- 1- t `1 + 1 + 1 J f l! II t t~ 1 -a- t 1 aCL. w !> 1 "1 I\ 1 1 * i" 1 y <St a (/CC>a>l>L -5- CQ3L. " \\ I t H. I 1 t _ 1 ^ // j ^ J h ?^ J J /</ (a) tb) (cl Fig. 11. Methods of Arranging Hot Water Circulation Lines 1 /<$ valve should be placed in the hot water return pipe so that the rate of cir culation may be adjusted. Where the hot water piping system is exceedingly long, a water circu lator is frequently installed and controlled from an immersion thermostat on i!^e re^urn i'ne) set to start and stop the pump over approximately a 41 F deg temperature range. CONTROL OF SERVICE WATER TEMPERATURE Coal-fired boilers are usually controlled by an immersion thermostat , seated in the heated water) which opens or closes draft dampers at the ooiler to adjust the rate of fuel combustion. With oil or gas-fired boilers, ri|e lmmersion thermostat controls the oil burner or the automatic gas valve. ie gas pilot flame usually burns continuously. With electric heaters, the Emersion thermostat operates a switch on the source of energy, t ^hen steam or hot water is the medium for heating the water in the ank, an immersion thermostat is used to control a valve in the steam or ot water supply line. In small residence installations, using water as the rrior, ^ combined immersion thermostat and butterfly valve in one simple 1086 CHAPTER 49 1954 Guide fitting may be installed in the transmitting circuit to prevent over-heating of the service water. In residences heated by pump circulated hot water, the house tempera ture is controlled by operating the circulating pump intermittently, while domestic hot water is warmed by transfer from the house boiler, inde pendent of the pump operation. The domestic water is heated from the heating boiler the year 'round. Under such an arrangement, to prevent 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 puinp 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 tem perature. When hot water is removed, the cold water entering to replace it quickly reduces the temperature in the lower parts of the tank. 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 explosions. 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 external 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 in crease in volume of about one-half gallon. If the tank is connected to some supply 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 pressure 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 increase. 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 thermal 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 quantity of water to relieve any pressure rise due to the thermal expansion of the water. The rate <# 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 gallon5 per minute may be computed by Equation 3: Water Services 1087 ~ 0.000056 (3) where b is the heat input of heater in Btu per minute. To prevent danger of overheating, temperature-relief devices 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 incor porates 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 cutoff 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. tion^f ca^)ac'^ temperature relief devices may be calculated by Equa- Qm = 0.00086 - (4) where Qm 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 cor rosion 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 water. The suc cessful operation of such heaters requires the availability of sunshine practically every day in the year, which has limited their use to Florida and the southern portions 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 intermittent. They have peen used in summer homes as far north as Chicago. When properly installed and proportioned, solar water heaters render satisfactory service, especially in climates where the outside temperatures are high and ex tremely hot water is not necessarily desirable. Such installations consist pssentially of a storage tank, heating coil, and hot box. The coil is installed hi 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 1088 . CHAPTER 49 1954 Guide requires no fuel. The same materials should be used for the coil, circula tion lines, and tank. A copper coil is more efficient in absorbing heat in the box, but galvanized iron or steel may be substituted, 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 sun conditions 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 temperature of all of the water in the tank to an unsatisfactory point for usage, the equation for calculating the storage capacity of the tank becomes: ,, QA X 050 5 = 0.75 0.666<?d (5) where S = storage capacity of tank, gallons, 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. 12, 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. The coil should be of the return-bend type (square or slightly rectangu lar in form), and should have the pipes running 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 adjacent ob structions 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 circula tion 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. 13, so that the north end is raised above the south end to secure an angle with the hori zontal 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 conditions along the 30-deg N latitude, which includes the portions 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 sash are placed over the top of the box, and the box should be constructed as air-tight as possible. The interior surfaces 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. i Water Services 1089 Table 12. Suggested Solar Heater Design Data* Design Item Based on Rate op 30 Gal per Dat per Person Based on Rate op 40 Gal per Dat per Person No. of Occupants in Residence.. Hot Water Used at Night, gal per person................................ 1 2 3 4 5 6 7 '8 i 2 3 4 5 6 7 8 15 15 15 15 15 15 15 15 20 20 20 20 20 20 20 20 total.......................................... 15 30 45 60 75 90 105 120 20 . 40 60 80 100 120 140 160 Retained in Tank, 25 per cent, 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 94 113 130 160 25 50 75 100 125 150 175 200 Hot Water Used During Day, gal 15 30 45 60 75 90 105 120 20 40 60 80 100 120 140 160 35 70 104 135 169 203 235 27C 45 90 135 180 225 270 315 360 Gal per hour............................... 4.5 9 13 17 21 26 29 34 6 12 17 23 28 - 34 39 45 Copper Coil Required: Surface area, aq ft............._........ 25 50 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 25 50 75 100 121 145 168 192 32 64 96 128 160 192 224 256 Width, ft...................................... 4 6 7 8 9 10 10 11 4 e 8 9 10 11 12 12 Length,ft.................................... 8 11 12.5 13.5 14.5 16.5 17.5 8 10 12 14 16 18 19 21 6 Sun Effect and the Design of Solar Heaters, by H. L. Alt (A.S.H.VJE. Transactions, Vol, 41,1935, p. 131). 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. Otherwise, only part of the heat enters the coil, the balance being transmitted through the glass. Design data given in Table 12 may be used with judgment in selecting the size of solar heater coil and box for a particular application. These data are based on consumptions of 30 and 40 gal of hot water per day per person. 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 exchanger 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 avail able, and one particular arrangement is shown in Fig. 14. Hot water heating by means of a heat pump is not yet advisable where Fig. 14. Heat Pump Arrangement for Hot Water Supply 1090 CHAPTER 49 1954 Guide 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 eliminating products of combustion, odors and soot, and not needing a chimney. A further advantage is that they may be used for cooling purposes. With a coefficient of performance of 2^ to 3, water temperatures of 140 to 150 F may be obtained.5 REFERENCES 1 Water Distributing Systems for Buildings, by R. B. Hunter (National Bureau of Standards, Report BMS79, p. 6-9). (Charts extended to flow of 0.39 gpm). 1 Private communication from Howard E. Degler. * Enough Hot Water--Hot Enough, by J. Stanford Setchell (American Gas Asso ciation, 1950). 4 Plumbing Practice and Design, by Svend Plum (John Wiley and Sons, Inc., 1943). 1 Progress Report on a Heat Pump Water Heater, by P. Sporn and E. R. Ambrose [Heating and Ventilating, February, 1949, Vol. 46, p. 78). BIBLIOGRAPHY Laundry, Kitchen and Hospital Equipment, by H. C. Russell (A.S.H.V.E. Trans actions, Vol. 35, 1929, p. 45). Water Consumption, Cost and Savings, by G. C. St. Laurent (American Hotel Association, Hotel Engineering, Vol. 1, 1940). Water-Supply Piping-for the Plumbing System, by F. M. Dawson and A. A. Kalinske (Technical Bulletin No. 3, National Association of Master Plumbers). ' Use of Solar Energy for Heating Water, by F. A. Brooks, Smithsonian Institution, Washington, D. C. Methods of Estimating Loads in Plumbing Systems, by R. B. Hunter (National Bureau of Standards, Report BMS65, 1940). Plumbing Manual, Report of the Sub committee on Plumbing, Central Housing Committee on Research, Design and Con struction (National Bureau of Standards, Report BMS66,1940). Water-Distributing Systems for Buildings, by R. B. Hunter (National Bureau of Standards, Report BMS79, 1941). . Hot Water Requirements, by M. B. Mackay (Modem Sanitation, August, 1949, Vol. 1, p. 30). Urban Domestic Water Consumption, by M. A. Pond (Journal of the American Water Works Association, Vol. 31, No. 12, 1939, p. 2003). CHAPTER 50 residential summer air conditioning Equipment Capacity Selection, Types of Equipment, Types of Application, Room Air Conditioners, Central Systems for Summer, Central Systems for Heating and Cooling, Location of Cooling Equipment, Noise, Air Distribution Methods, Operating Costs, Effects on Future House Design IN RECENT years, summer air conditioning in residences has developed to the stage where it has become a maj or factor in the air conditioning field and has created a heavy interest among home-owners, builders, architects and business men. Residential cooling, particularly for the small, home, received its initial impetus when equipment specifically designed for such purposes became available in the 1930's. Recently it has caught the public fancy resulting in a tremendous increase in the number of sales and installa tions. The first installations were made by using the commercial and industrial methods as the estimating basis and did not prove as satisfactory as the installer or designer desired. Actually, the difference between estimating the residential summer air conditioning and commercial summer air condi tioning loads is in the design temperature differences used, the type of internal load in the conditioned area, and the method of calculating equip ment size. EQUIPMENT CAPACITY SELECTION With cooling, as with heating, the proper equipment capacity selection is that which, when properly installed, maintained, and operated, will satisfy the customer. Although at present an indoor design temperature of t5 F is used only on deluxe installations, it is felt that eventually this temperature will be used as the basis for design for both heating and cooling systems.. At the present time, however, most summer air conditioning installations are designed on the basis of an 80 F indoor temperature. The outdoor design conditions commonly used in each locality are those listed m Chapter 13. In calculating residential cooling loads, internal loads are not taken into consideration as much in domestic summer air conditioning as in .commercial or industrial summer air conditioning. Lighting, electrical Appliances, and so on, are not considered except in the cases where unusual oads are added to the conditioned area by means of certain types of r^ese Appliances, such as clothes dryers, and water heaters, " ou be vented to the atmosphere in order to limit their effect on the summer cooling load. in methods of calculating the cooling load which are presented Chapter 13 may be used for calculating residential cooling load, it has act11 i?uncb *^At the load so calculated is much greater than that which is j u,a *y expericnced in most residences. This is objectionable from at two viewpoints: (1) it increases the capacity and consequently the 1091 1092 CHAPTER SO 1954 Guide cost of the equipment installed, and (2) because of the increased size it re sults in less desirable humidity conditions within the residence. A number of manufacturers, as well as several organizations, have been working on methods of calculating.summer air conditioning loads for do mestic applications. One of these is the method developed by the National Warm, Air Heating and Air Conditioning Association in conjunction with the Air-Conditioning and Refrigeration Institute. This method is based on a load at a particular time of the day and takes into consideration the amount of solar radiation and heat gain due to the temperature difference between the conditioned area and the outside area on the assumption that the peak cooling load occurs from 3:00 to 4:00 o'clock in the afternoon. Methods have been devised to calculate instantaneous heat loads for the 24 hours in a day and others have been devised to use the peak loads and allow for temperature time delays due to the construction of the residence. TYPES OF EQUIPMENT Low Side . Three types of low sides (the equipment that actually removes the heat from the conditioned space) have been developed for residential work as follows: (1) water-cooled coil, (2) chilled-water coil, and (3) refrigerated coils. The water-cooled coil using water directly from the supply sources, such as city water or a well is the most simple type of installation. Cold water is circulated directly through the coil while air from the conditioned space is passed over the coil to remove heat and moisture. After the water has passed through the coil, it is wasted. To operate satisfactorily, an installa tion of this type requires water of sufficiently low temperature to chill the air enough to remove the desired amount of heat and moisture. Where a large supply of water at a cold temperature is obtainable, the water-cooled coil will operate with satisfactory results. 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 cooling 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 using mechani cal refrigeration. This is known as a chilled-water system. ' In a chilled-water system, water is circulated through a closed circuit containing two coils. In one coil the water removes 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 system 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 third method of absorbing heat from the conditioned air is by means of direct evaporation of the refrigerant in a coil with the air to be condi tioned passing over the outside of the coil surface. The heat is passed directly from the air into the refrigerant for removal. 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 Residential Summer Air Conditioning 1093 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 compressed 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 circulated. 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 disadvantage is that operating pressures are higher because of the inability to cool the refrigerant as much by air as by water. This results in anjncrease 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 be cause of lower equipment cost and lower operating costs and quieter opera tion. In a second type, if water is in short supply or is expensive, about 95 per cent of the cooling water can be reclaimed by evaporating sufficient water to rid the remaining 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. These units are described in Chapters 35 and 37. TYPES OF APPLICATION The common ways of cooling residences today are by the use of room air conditioners, central systems for cooling only, or central systems de signed for both summer cooling and winter heating. The choice between these methods is largely one of cost and the relative heating and cooling loads. ROOM AIR CONDITIONERS Window and cabinet-type air conditioning units can be used to cool small sections of a house. The window units fit into an opening of a.standard double-hung window and vary in size from K to 1 ton of cooling capacity. Room air is circulated .rough the unit where it is cooled, dehumidified, and filtered. No water pipes are necessary since the condenser is air-cooled; nor is a drain necessary maanucb as the moisture condensed from the air is evaporated into the ou oor air. Electrically operated, the units can generally be plugged into xisting electrical outlets although a voltage of 220 is required for units naving one-horsepower motors. Cabinet units stand on the floor and require an opening in the wall rough which air to cool the condenser is brought in and discharged, i r?om cooler is popular for use in offices or residences where the exist ed r6at-mg system does not contain provision for summer cooling or where oonng is not required in the entire space. . CENTRAL SYSTEMS--SUMMER ONLY need fme areaS ^cre's or ,no need for heating but there is a distinct or summer cooling. Both air- and water-cooled package cooling units 1094 , -CHAPTER SO 1954 Guide' are available for such installations, ranging in size from one ton to at least 15 ton 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 can also be used to provide central air conditioning to residences having heating systems which do not contain provision for attaching summer cooling equipment. CENTRAL SYSTEMS--HEATING AND COOLING A summer air conditioner can be installed beside or near an existing warm-air furnace and can be connected to the duct work if the duct system has ample capacity for the cooling operation. If it does not, additional ducts and supply outlets will be required. The conditioner is about the same size or slightly smaller than a conventional forced warm-air furnace. Year-round air conditioners require less space than a separate heating plant plus a separate summer conditioner. Usually the heating and cooling portions of a year-round air conditioner operate independently of each other,- The air circulated by the fan passes through the cooling or heating portion of the equipment, only one of which is in operation at any one time. Cool air supplied to rooms is usually 15 to 25 deg lower than the tempera ture of the rooms to be cooled. The size of the ducts of year-round air condi tioning systems are often larger than those of equivalent winter heating systems because large quantities of cool air at 55 F to 65 F must be circu lated through them. Duct systems should be designed and installed by com petent engineers in accordance with such authoritative information as the design manuals of the Air-Conditioning and Refrigeration Institute and the National Warm Air Heating and Air Conditioning Association} The cooled air is admitted to the room from the ducts through supply outlets. Since this air is colder, and therefore, heavier than the air within the room, it has a natural tendency to fall toward the floor. Unless the supply outlets are properly selected, located, and adjusted, the air distribu tion is likely to result in (1) a low velocity of cool air falling on the occu pants, or (2) a high velocity stream of cool air striking a wall or other ob struction and splashing on the occupants. Research is being conducted to determine the most advantageous type and location of supply outlets. The most commonly used outlets are registers with either fixed or adjust able vanes, and diffusers. Registers distribute the cooled air throughout the room. They are usually located either high or low in the sidewall or m the baseboard. The diffuser type of outlet can be used in ceiling, wall, or floor. Different designs are available for each of these locations. The floor, baseboard, and sidewall diffusers blanket the walls with a curtain of cool air (or warm air in winter); the ceiling diffuser blankets the ceiling. Air conditioning can be installed in homes having a hot-water heating system either by use of: 1. Room units 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 split system. The cooling coil is located in a duct through which air from the rooms is circulated, cooled, and returned to the rooms. The coil can be used for winter Residential Summer Air Conditioning 1095 heating, or conventional radiators, convectors, or panels can.be used to bring the . heat to the rooms. ^ The cooling equipment is located in the basement or utility room near the boiler. Valves are provided so that the same piping system can be used to circulate heated water in winter and chilled water in summer.The piping must be insulated to prevent sweating when circulating cold water. LOCATION OF COOLING EQUIPMENT The location of the summer cooling equipment will depend upon the type of unit. In a combination self-contained type unit, the location will depend upon accessibility to the duct system, the fuel supply, and the electrical supply. Too often, a heating or cooling unit is located by giving considera. tion to installation only, without considering the usability of the basement. This may result in breaking up the basement area to each an extent that it becomes practically useless for other purposes. In a remote type combina- Fig. 1. Combination Summer Air Conditioning and Hot Water Heating System tion unit, consideration' must be given to the location of the condensing unit, whether it is located in the basement area or whether the unit is lo cated in a remote area such as the garage breezeway. Preferences of the lamily and their habits of living must be given consideration so as to keep ml space as useful as possible and still locate the equipment in such a place that it can do its intended job and be accessible. NOISE One of the prime problems of domestic air conditioning is operating noise. uue consideration must be given to location of summer air conditioning equipment, with respect to areas under bedrooms or other rooms requiring very low noise levels. Equipment is often installed without due considerajon to blower and duct sizes, with a resulting increase in noise level. Con sideration should be given to the use of vibration absorbers in refrigerant !'i i: : ; l'"` .! !.;. ,1 ! - I; 1096 .CHAPTER 50 1954 Guide and water lines, to anti-vibration padding under equipment, and to flexible duct connectors to isolate operating sounds. AIR DISTRIBUTION METHODS Where cooling is installed with ducts and air outlets which serve the cooling function only, the practice and experience of comfort air condition " ing for offices and commercial buildings apply directly to residential installa tion. Although cooling and heating by means of the same duct work and air outlets has been common practice in commercial and industrial applica tions, it must be handled carefully in residential applications. It has been found that low air-flow rates are desirable for warm-air heating systems,4 much lower than would be used for cooling systems. It is therefore recom mended that, in a residence located in a moderate or cold climate, provision be made 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 sidewall or in the perimeter location. For the high sidewall applications, it is necessary that the deflec tion of the air be different for summer 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,6 it is not necessary to change the deflec tion from summer to winter. The air distribution system should be designed for the largest air-flow rate which is to be used, as outlined in Manual No. 113 of the National Warm, Air Heating and Air Conditioning Association. For small-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 registers 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 shown6 that the use of perimeter duct systems for air conditioning gives excellent results, and that objectionable air motion does not occur within the living zone except in the immediate vicinity of the registers. Care must be taken, however, to use only registers or diffusers that are specifically designed for perimeter application. This is necessary to permit the introduction of the air into the room in a pattern which does not cause drafts. Floor diffusers which distribute the air in a fan-shaped pattern along the wall or low sidewall diffusers which blanket the wall are recommended. For supply-air temperatures not more than 15 deg below room-air temperatures, diffuser face velocities of 500 fpm are recommended. For supply-air temperatures 20 deg below room-air temperature, the dif fuser face velocity should not be less than 700 fpm. OPERATING COSTS A sufficient number of residential air conditioning installations have been made in most areas to supply local experience on operating costs. Although this experience generally indicates that the operating costs are not an important factor to the users, they usually are considered on new construction by the financing organizations. Residential Summer Air Conditioning 1097 When operating costs are to be estimated, it is well to secure information based on the local experience and to take cognizance of the following factors: 1. There is much variation in the operating practice between users, in that some home owners keep their homes closed and on thermostatic control at all times, where as others use their cooling equipment only in the extreme of hot weather. 2. The possibility of opening the windows at night to take advantage of night-air cooling should be considered.* 3. In some areas, cooling requirements vary considerably from one year to the next so that averages are not representative of any one season's expectancy. 4. Since the cooling load of a residence has only a small component of internal heat, it is much more subject to weather variations than commercial installations which have a much higher component of internally generated heat load. - 5. Vacation periods may also offset the operating costs. EFFECTS ON FUTURE HOUSE DESIGN Air conditioning, like automatic heating, has brought about improved practice in residential construction, particularly in those regions where cool ing is of primary importance. Although it is true that construction practices which reduce the heating load also reduce the cooling load, there are certain considerations which are unique in their effect upon the cooling load. Special attention must be paid to window orientation and means of shading the windows. South windows may be shaded by awnings or roof overhangs, but it is not practicable to shade large window areas having an east or west orientation except by exterior 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 ventila tion of the attic. Double-glazed and weatherstripped windows, heat-absorb ing glass, planned shade tree locations, and light colored exterior wall and roof surfaces, also help to reduce the cooling load. REFERENCES 1 Cooling a Small Residence with a Two-Horsepower Mechanical Condensing Unit, by H. T. Gilkey, D. R. Bahnfleth, and R. W. Roose, (A.S.H.V.E. Journal Section of Heating, Piping and Air Conditioning, February 1953). 1 Application Engineering Standard for Year 'Round Residential Air Conditioning (Air-Conditioning and Refrigeration Institute, 1953). 3 Summer Air Conditioning, Manual No. 11 (National Warm Air Heating and Air Conditioning Association, 1953). * Continuous Air Circulation, Manual No. 6 (National Warm Air Healing and Air Conditioning Association, 1947). * Comparative Performances of Two Warm Air Perimeter Systems and Three onvection Systems, by M. E. Childs, R. W. Roose, H. T. Gilkey and S. Konzo, n'':crsity of Illinois, Engineering Experiment Station Bulletin 403, 1942). ' Cooling a Small Residence Using a Perimeter-Loop Duct System, by D. R. Bahneth, C. F. Chen and H. T. Gilkey, (A.S.H.V.E. Journal Section, Heating, Piping arid Air Conditioning, February, 1954). 1098 , . CHAPTER 50 1954 Guide 7 Room `Air Distribution Research for. Year 'Round. Air Conditioning, Part II-- Supply Outlets at Three Locations, by H. E. Straub, and S. F. Gilman. (A.S.H.V.E Journal Section of Heating, Piping, and Air Conditioning, November 1953, p. 145). _ 8 Investigation of Summer Cooling in the Warm Air Heating Research Residence by A. P. Kratz, M. K. Fahnestock and S. Konzo, (University of Illinois, Engineering Experiment Station Bulletin 290j 1930)1 ' ' CHAPTER 51 INSTRUMENTS AND MEASUREMENTS Temperature Measurement, Pressure Measurement,, Air Flow Measurement,, Air Change Measurement, Humidity Measurement, Heat Transfer Through Building Materials, Evaluation of Thermal Environment, Combustion Analysis, Smoke Density Measurements, Determination of ; Air Contaminants, Sound and Vibration Measurements HEATING and air conditioning engineers and technicians require instruments for both laboratory and field use and somewhat more pre cision is attainable and essential in the laboratory, where research and de velopment are undertaken, than in the field, where acceptance and adjust ment tests are conducted. Some instruments have attained an adequate state of development, while others fall far short of the desirable. For in stance, temperatures can now be measured readily with ample accuracy for most purposes, while a convenient and precise method for determining or comparing the dustiness of atmospheres is lacking, and improvement in existing hygrometers and humidity controllers is essential.- Codes and standards covering different types of heating and air condi tioning devices and apparatus have been promulgated by various authori tative organizations, and instruments essential for performance or com pliance testing are enumerated in the relevant publications.1-2-3- 4 The present purpose is to discuss the use and characteristics of the more im portant instruments. . TEMPERATURE MEASUREMENT5-6 Thermometers .. . Any device capable of indicating temperature is a thermometer, but in common usage the term thermometer without qualification has come to signify the ordinary mercury-in-glass temperature indicating device. This type has a useful range from -- 40 F, the freezing point of mercury, to about 1000 F, at or near which the glass usually softens. Lower temperatures can be measured with alcohol-filied 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. The probable error for etched stem thermometers.'is plus or jnmus one scale division, and calibration is desirable for much test work, thermometers are calibrated during manufacture at not less than two temperatures--the freezing and boiling points of water--and calibration 11 tv?11 accomPlisbed with the instrument completely immersed in. a bath j.;TM known temperature. The intervening scale divisions are then ap plied to the stem. When such a thermometer is used with the stem in completely immersed, a correction known as the stem correction is neces sary for accurate measurements, and its magnitude is usually computed, oy means of the following formula: . where K = 0.00009 D (1, - t,) , K = correction to be added, Fahrenheit degrees. 1099 ' ' " ' (1) ': 1100 CHAPTER 51 1954 Guide D = number of degrees on the thermometer scale which are not immersed, ti = temperature indicated on the thermometer, Fahrenheit. ts = temperature of the non-immersed mercury column, Fahrenheit. 0.00009 = difference in the coefficient of expansion of the mercury and glass. When a thermometer is used in a liquid or in air or gas near room tem perature, the effects of radiation can often be ignored, but when the tem perature of hot air or gas is desired, means are usually provided for mini mizing the effect of radiation.7 These include bright metallic shields around the thermometer bulb, and the use of aspirated thermometers in which a stream of the air or gas is drawn at considerable speed across the bulb and increases the influence of the gas temperature on the thermom eter indication. In any case, to prevent errors in temperature measure ments, there should be ample circulation so that the thermometer will indicate a true temperature of the medium under observation, and ample time should be allowed for the thermometer to reach the same temperature as the medium. In reading a thermometer the eye should be at the same level as the top of the liquid to avoid parallax. 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 con siderable heat capacity and conductance of the guards or shields prevent such thermometers from following closely the fluctuations in. a medium of varying temperature. Thermocouples When two wires made of dissimilar metals are joined by soldering, weld ing or merely by twisting, a thermocouple or thermo-junction is formed and an electromotive force, which depends upon the temperature of the junc tion, is found to exist between the wires. When the wires are joined at two points a thermocouple circuit is formed, and 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 developed by the two junctions. This phenomenon is employed for temperature measurements in thermocouple systems, one junction being ordinarily kept at a constant temperature, as in an ice bath, while the other junction is placed at a point at which it is desired to observe the temperature. In practice it is desirable to utilise emf to indicate temperature because, at small or zero current flow, the resistance of the circuit is unimportant. A high resistance millivolt meter is useful in some cases but the potentiometer yields better results. In the potentiometer the electromotive force generated by the thermocouples is balanced against an electromotive force from the battery so that observetions are made with no flow of current through the thermocouple circuit. A conventional arrangement is illustrated in Fig. 1. The thermocouple leads A-B are so connected that their polarity opposes that of battery C. If the position of E on the graduated slide wire rheostat DF is adjusted until galvanometer G shows no current flowing, resistance DE will indicate directly the voltage generated by the thermocouple. In order to calibrate the instrument, switch S is thrown over to the standard cell circuit while rheostat R is adjusted so that the galvanometer shows zero current. Bat tery C then exerts the known voltage of the standard cell at DH. ` The choice of materials for thermocouple wires is determined by the range of temperature to be measured. Up to about 600 F base metals such as iron-constantan or, preferably from the corrosion standpoint, copper constantan are satisfactory and develop a relatively large emf of 40 to 60 Instruments and Measurements 1101 microvolts per degree. Chromel-alumel couples are useful in the flue gas temperature range, while platinum (platinum-rhodium) couples are used for higher temperatures. Impurities make large differences in the perform ance 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 obtained from the manufacturer. The act of adjusting rheostat D-F (Fig. I) for zero current flow is known as balancing the potentiometer. Automatic self-balancing instruments of both the indicating and recording types are on the market. They usu ally contain an automatically compensating cold junction to avoid the use of an ice bath, and special thermocouple wire is furnished with them from the factory. With a suitable potentiometer, small wires serve as well for thermo couples as large ones, and the fineness of the wires is limited only by consid- Fig. 1. Basic Circuit and Connections for Thermocouple and Potentiometer Fig. 2. Typical Resistance Thermometer Circuit and Connections eration 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. For use in heated air or gases, thermocouples are often shielded, as are thermometers, and aspirated thermocouples are sometimes used. An arrangement has been described for avoiding error due to radiation. It involves several thermocouples of different sizes, the true temperature being estimated by extrapolation of readings to zero diameter.8 By the use of thermocouples, temperatures at remote points may be indi cated or recorded on conveniently located instruments; average; tempera ture may be readily obtained by connecting several couples in parallel or in series; and temperatures may be obtained within thin materials, narrow spaces, or otherwise inaccessible locations. Thermocouples in series with every alternate junction maintained at a common temperature will give an emf which, divided by the number of couples to give the average emf9 per couple, may be used to find the aver age temperature. Thermocouples in parallel, having the similar metals of a number of couples connected together and run to a common cold junction, wall cause an indication on a potentiometer which is the true emf only if the electrical resistances of the parallel junctions are the same.9,10 1102 CHAPTER 51 1954 Guide , Temperatures of surfaces below red heat are difficult to determine by any other means than thermocouples. For this purpose, a thermocouple of fine wires is preferable to minimize the possibility of error due to the conduction of heat along the wires. It may be attached to.a metal surface in any of several ways.. For permanent installations, soldering, brazing or peening may be desirable. A small hole is drilled for the peening opera tion; the thermocouple is inserted and the metal is peened to retain it. The fact that the thermocouple is in electric contact with the surface is unimportant in usual circuits. For temporary arrangements, couples may be attached by means, of surgical or cellophane tape. For many boiler or furnace surfaces, furnace cement serves very well. The thermocouple may be attached by means of the cement when the surface is cold, and must be treated gently and usually supported until the cement dries, due to heat, and hardens--after which it has ample strength. It is good practice to use as little cement as possible, and also to plaster the wires to the surface for an inch or so from their junction to avoid errors due to heat conduction along the wire. Electric insulation between the wires should be perfect except at the junction since, otherwise, the indicated emf will be between those existing at the junction and at the short circuit. Resistance Thermometers Resistance thermometers depend for their operation upon the change of electric resistance of metal with change in temperature. The resistance generally increases with rising temperature. 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 which coils L and H exert opposing forces on the indicating needle. . Coil L is in series with the ther mometer 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 causes an in crease 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 indicating 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 thermometer does not require a cold junction, and it can be simply scaled for more accurate meas urements; but, generally because of its construction it is more costly and is apt to have considerable lag. It gives best results when used to meas ure steady of slowly changing temperature. For accurate results the entire thermometer coil must be exposed to the temperature to be measured. 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 Instruments and Measurements 1103 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 speci fied 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 appear ance probably is familiar to any one 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-section curved along its length to form al most a 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 pres sure, the tube tends to straighten, and vice versa, and 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. Gages are commonly set to read accurately at. or near the pressure of probable use. Gages of several different types or qualities are available on the market.11 Suction gages and pressure, gages with. ranges below about 20 psi are ordinarily calibrated against mercury manometers. Manometers . .. The manometer is a simple and useful means for measuring partial vacuum and low pressure. It is, moreover, a primary instrument; it does not 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 measure ment. 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 propor tional to the difference in height. For converting manometer readings into 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 nre 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 = 34.0 ft (408 in.) water column Manometer tubes should be chemically clean. The bore is not impor- ant, except insofar as it affects the meniscus through wetting or surface ten10n- Bores of at least in. for rough, and 5 in. for more precise, measure 1104 CHAPTER 51 1954 Guide ments 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 used. For measuring pressure differences of a few inches of water, or less, Ugages 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.12 The accuracy of a draft gage is dependent on the slope of the tube, and consequently the base of the gage must be leveled carefully. 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 nor mal temperature, it is necessary to correct for the change in density of the liquid in the manometer.1* For measuring low pressure differences to within 0.001 in. of water, very sensitive micromanometers are available, such as the Illinois or Wahlen, the Meriam, the Trimount, and the Emswiler.14,16 When using a manometer or other pressure gage for measuring air flow, by means of orifices, the type of duct openings used for manometer con nections and their location are important. Where velocities are low, as in some plenum chambers, or where the flow is free of large eddies and parallel to the walls of a duct; a drilled hole cleared of burrs and at right angles to the stream, is satisfactory.16 For higher velocities, it is common practice to provide four holes or taps around the periphery of the duct. Diamet rically opposite pairs of taps are connected together, and then such pairs are manifolded together. An alternate method involves the use of the Pitot tube, shown in Fig. 3. This instrument should be pointed up-stream, parallel with the air flow. Where the flow is not axial or parallel to the side walls of the duct, a very close approximation of the static pressure and the flow direction can be obtained by a Fechheimer tube.17 Barometer The simplest and earliest type of barometer consists of a glass tube some what more than 30 in. long filled with mercury, and inverted in a cup par tially filled with mercury. The height of the mercury column in the tube above the mercury surface in the cup is a measure of the existing atmos pheric 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.18 The instruments are usually cali brated for 32 F mercury and 62 F scale temperature, and the correction C to be subtracted from the observed barometer's height is obtained by means of Equation 2. h(t - 28.630) 0 = (1.1123 10978) where C = correction to be subtracted, inches of mercury. Instruments and Measurements 1105 h = observed height, inches of mercury. '' t - 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 important to make a correction if the elevation of the barometer 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 barometers. Most of the pres sure gages used in engineering work indicate gage pressures, that is, the Fio. 3. Standard Pitot Tube difference between the pressure being measured and the atmospheric pres sure. Such pressures are called gage pressures. Absolute pressure may be obtained by adding barometric pressure and gage pressure algebraically. AIR FLOW MEASUREMENT The theory of various means for measuring the flow of fluids is discussed in Chapter 4, Fluid Flow. Heating and air conditioning engineers axe 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 can be used with sufficient accuracy for the solution of many problems.19 The Pitot Tube The construction of the Standard Pitot Tube12 is shown in Fig. 3. The formula for velocity used in conjunction with it, is as follows: Fm = 1096.5 (3) 1106 CHAPTER 51 1954 Guide where Vm = velocity, feet per minute. h\r 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. Suggested Pitot tube locations for traversing round and rectan gular ducts are shown in Fig. 4. In general, the velocity is lowest near the edges or comers, and greatest at or near the center. For this reason a large number of readings should be taken (in the case of round ducts not less than 20) along two diameters at centers of equal annular areas. Iii 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 riot be more than 64. When less than 64 are taken, the number of equal spaces should be such that the centers of the areas are riot more than 6 in. apart. In determining the average velocity in the duct from the 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 er roneous results and therefore, if possible, the Pitot tube should be located at least 7J diameters down-stream from a disturbance such as that caused by a turn ; or a criss-cross type of flow straightener should be installed in the duct 1J diameters ahead of the Pitot tube.12 Flow straighteners do not equalize flow velocity across a duct. They merely serve to improve the precision of measurements. Equalization can be effected, if desirable, for measuring purposes by the use of wire netting, perforated plates or cloth screens across the duct. , Many forms of Pitot tubes, other than the one described, have been used and calibrated.20 A double-ended tube,21 one end pointing down-stream, and one up-stream, is sometimes used for low velocities, but it should be carefully calibrated for accurate results. A special form of this tube design consists of two straight in. tubes soldered together, 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 Instruments and Measurements 1107 around grinding wheels. To meet special conditions, different sized Pitot tubes which are geometrically similar to the standard tube can be used. Plate Orifices Application of the Pitot tube is often inconvenient when velocities are low, because the resultant velocity pressures become so small that extra ordinary means are necessary for measuring them. In addition, velocity surveys of the whole cross-sectional area of a duct are inexpedient when numerous test runs are in prospect. Chiefly for these reasons orifices are favored for much test work. There are two types: the plate orifice and the shaped orifice or nozzle. Plate orifices are simple to construct and con venient to use, in that a frame can be made to support them in the duct such that one can be removed and another inserted when it is desirable to use an orifice of a different size: Formulas for Orifices In the heating and air conditioning fields it is usually convenient to obtain orifice pressure drops in inches of water column, temperatures in Fahrenheit degrees and barometric pressure in inches of mercury. The air flow is usually desired in cubic feet per minute at the existing condition, so that velocities in various ducts can be computed, and in pounds per hour so that computations of heat transferred by the air can be based on weight, tem perature change and specific heat. Equation 4 is applicable. Qm = 5.2KYB* VI h, W where Qm = air flow, cubic feet per minute. K = orifice coefficient. Y = expansion factor, see Fig. 5. D = orifice diameter, inches. <f = pipe diameter, inches. T1 = temperature of air at orifice, Fahrenheit, absolute. Bi = absolute pressure ahead of orifice, inches of mercury. = absolute pressure after orifice, inches of mercury. hw = pressure drop through orifice, inches of water. As most laboratories are less than 1000 ft above sea level, precision is adequate in many cases if standard atmospheric pressure, 29.92 in. Hg, is assumed. Equation 4 then becomes Qm = 0.95 KYD' VT,K,, After the flow in cubic feet per minute is determined, it can be expressed in pounds of air per hour by means of the relation W = 60 BT, P = pressure, pounds per square inch, absolute. R = 53.3, the gas constant for air. T, = temperature of the flowing air, Fahrenheit, absolute. (6) The thin-plate square-edged orifice often has a discharge coefficient K 1108 . CHAPTER 51 1954 Guide near 0.60. The exact value depends on the location of the connections, the pressure drop, the diameter ratio of orifice to pipe, and the sharpness of the edge.22'23 Other information on orifices and their use is contained in Chap ter 4, Fluid Flow. '. . Shaped orifices or nozzles have the advantage, if well made, that their discharge coefficients are close to unity so that the probability of large errors is less. Orifices of this type have been adopted for several specific purposes, and designs are.described in the A.S.H.V.E. Unit.Heater1 and Unit Venti lator Codes,2 and in A.S.R.E. Circular 133 entitled "Standard Methods of Rating and Testing Air Conditioning Equipment". In some instances nozzles are used in multiple so that the capacity of the 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 Wile24 in an article in which pertinent informa tion on nozzle discharge coefficients, Reynolds numbers, and the resistance Fig. 5. Expansion Factob fob Aib and Otheb Diatomic Gases Applicable to Flange, Radius and Vena Contbacta Taps of perforated plates is also presented. Such apparatus in some laboratories is commonly referred to as a code tester. The Venturi meter is like the nozzle, except for the addition of a down stream transition section that reduces the pressure drop through the meas uring apparatus. . In some cases air velocity through a duct, heater coil, or heating unit may be most conveniently 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 plane of temperature measurement. Propeller or Revolving Vane Anemometer The propeller or revolving vane anemometer consists of a light revolving wind-driven wheel connected through a 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 in various sizes, 3 in., 4 in., and 6 in. being most common. Each instrument requires individual calibration. At low velocities the friction drag of the mechanism is considerable. In order to compensate for this, a gear train that overspeeds is commonly used. For this reason the correc Instruments and Measurements ;: tion is often additive at the lower range and subtractive at the upper range; with the least correction in the middle range of velocities. Most of these are not sensitive enough for use below 200 fpm. Anemometers of this type are practically standard for wind measurements, and may be used in large ducts where the air flow is not seriously altered by the presence of the instrument itself. Deflecting Vane Anemometer 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 up-stream to a down-stream opening. The movement of the vane is resisted by a hair spring and a damping magnet. The instrument 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,25 and in locating objectionable drafts. Various attachments are available, such as the double tube ^arrangement for determining velocities in ducts, and a device for measuring static pres sures. Each instrument, and the attachments for it, must receive indi vidual calibration. For determining average velocity in a duct, it is neces sary to traverse the duct as is done when using the Pitot tube. Measurement of Velocities at Inlets and Outlets of Ducts . In the field it is often desirable to make volume measurements at the face of the supply openings. It is rare to have access to the interior of duct sections where the flow is sufficiently uniform for measurement. For ac curacy, 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 suc cessfully on most of the common types of supply grilles.26' 27 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 cor rected 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..28 When a propeller type anemometer is held in a stream of varying veloc ities, 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 mini mum velocity. This is the main reason for the large difference in ratings of unit ventilators by the anemometer method, and by air volume measure ments in a duct approach to the inlet.29 Anemometers can be 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 iet on the end of a rubber tube has been found especially convenient and accurate on supply grilles.30 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 1110 CHAPTER 51 1954 Guide 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 angle giving a maximum reading. With suitable traversing 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. Smoke is a qualitative tool which is very useful in studying air move ments. Satisfactory smoke can be obtained from titanium tetra-chloride (which, however, is very irritating to nasal membranes) or by mixing potassium chlorate and powdered sugar (a non-irritating smoke) and firing the mixture with a match. This latter process evolves considerable heat, and it should be confined in a pan away from flammable materials. The titanium tetra-chloride smoke lends itself to spot determinations, particu larly for leakage through casings and ducts, as it can be easily handled in a small pistol-like ejector. The fumes of aqua ammonia and of sulfuric acid, if permitted to mix, form a white precipitate which is useful for some purposes. Two bottles, one containing ammonia water and the other acid, are connected to a common nozzle by means of rubber tubing. Air is forced over the surfaces of the liquids in the bottles by means of a syringe, and the two streams, upon mixing at the nozzle, form a white cloud. The Kata Thermometer The measurement of air current velocities within enclosed spaces, such as the rooms of a house, is usually a tedious undertaking. However, useful data can be obtained by using the instruments described in following para graphs if they are maintained in calibration, and the user understands the operation and limitations of the instruments.82 One of the instruments useful for determining the velocity of air currents in free spaces is the Kata thermometer which is essentially an alcohol thermometer with a large bulb. The instrument is heated above 100 F, and then the time in seconds required for it to cool from 100 to 95, when located in the air current, gives a measure of the air speed. It is important to have the Kata thermometer dry before taking the reading. Each Kata has its own factor etched on the stem, and this factor must be used with its cooling formula or chart for obtaining the velocity. The Kata thermom eter is useful in exploring ventilated spaces to determine whether the proper air movement and distribution are being maintained. It is also used in determining 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.88 Thermal Anemometers If a suitable sensing element is heated electrically at a fixed rate and exposed to an air stream, the temperature difference between the element and the stream becomes a measure of velocity by calibration. In the hot-wire anemometer, a very fine heated wire is employed as a resistancethermometer element whose temperature may be determined accu rately.84-85 In the heated-bulb thermometer type, a heating wire is wound around the bulb of a mercury-in-glass thermometer, and the temperature difference between this thermometer and a similar unheated one serves as an index of air speed.85 The heated-thermocouple anemometer is cali brated to give velocity in terms of the differential emf between heated and Instruments and Measurements 1111 unheated thermo-junctions exposed to an air stream.84- 87 Combined measurements of air temperature and velocity are particularly useful for air distribution .studies, and automatic recording potentiometers or resist ance-thermometer devices facilitate spatial traverses. A correct calibra tion of thermal anemometers requires consideration of the effects of tem perature, humidity and pressure upon the air properties which influence convective heat transfer.87 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 sensitivity is controllable. Thermal anemometers are convenient and practical for low velocities. Infiltration or Air Change Measurement The total air leakage into an existing building caused by wind and tem perature difference forces can be determined with considerable accuracy by determining the decrease in 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 comparator.89 About one percent of tracer gas by volume is introduced into the room or building, and the tracer gas is thoroughly mixed with the air. The decrease in con centration of the tracer gas is observed at regular time intervals with a thermal conductivity meter as infiltration dilutes the mixture. The fol lowing formula is used to calculate the infiltration from the observed concentration measurements: C = (7) where C,, = initial tracer gas concentration, percent. C = concentration of tracer gas .after t minutes, percent. = volume of room or building, cubic feet. k = infiltration rate, cubic feet per minute. = 2.718, for natural logarithms. 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 concen tration. Psychrometers HUMIDITY MEASUREMENT Any instrument capable of measuring the humidity or hygrometric state of the air is a hygrometer. A psychrometer is a particular kind of hygrom eter 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 water and ventilated with air moving at a recommended rate of 900 fpm or more, rela tive to the instrument.49 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 arrested for reading the thermometers, and contin ued until the thermometer readings become steady. Due to evaporation, the wet-bdb thermometer will indicate a lower temperature than the drybulb thermometer, and the difference is known as the wet-bulb depres- -on- Charts and tables are available showing the relation between the thermometer readings and the humidity.41 42 Data are usually based on a total pressure of one standard atmosphere. For precise work, a correction 18 necessary for barometric pressure and is usually made by multiplying 1112 . CHAPTER SI 1954 Guide the observed relative humidity by the ratio of the observed to the standard atmospheric pressure. For air temperatures below 32 F, the water an the wick may either freeze or super-cool, and its state must be known and a proper table or chart used, since the wet-bulb' temperature 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 thermometers 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 laboratories, and several commercial models are available. The Dew-Point Hygrometer In the usual form of these instruments, means are provided for cooling, and of observing the temperature of, a surface which is exposed to air. The temperature at which visible condensation occurs on the surface is con sidered the dew-point of the air. With the dew-point temperature known, the relative humidity and other properties of the air can be taken 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 areUsed to cool the mirror from the back, including evaporating ether or another refrigerant, or a stream of air passed through dry ice. Dew-point temperatures, in some cases, are observed by means of thermom eters in fluids in contact with the back of the mirror, but in modem instru ments thermocouples are used, and are soldered or welded to the mirror itself. The dew-point apparatus is not so commonly used as the psy chrometer, probably because it is less convenient. It is usable, however, for higher temperatures than the wet- 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 apparatus for high precision has been con structed, in which the photronic cell and a light source are used for dew or frost detection instead of visual inspection. Hair Hygrometers Many materials, especially organic materials, change in dimensions with changes in humidity, and many devices have been designed in efforts to utilize this action in simple and effective humidity indicators, recorders and controllers. Unfortunately, no material has been found which can be relied upon to perfectly reproduce its action when exposed to repeated identical changes in humidity. The field has been well explored, and in strument and control manufacturers are practically unanimous in the selection of human hair for this service. The hair hygrometer consists of from one to several strands of hair with a mechanism whereby changes in length of the strands, due to changes in humidity, cause an indicator to move across a dial. In the recording instru ment, a pen is moved across and marks a moving paper ribbon, indexed in relative humidity. In a controller, or humidistat, the motion makes or breaks an electric contact governing the air conditioning equipment. Such devices require initial calibration and, for precise work, frequent recalibra tion or setting, especially if they are exposed to extremes of either high or low humidity. For continuous operation, with only slight changes in humidity, some operators report satisfactory reproducibility of results. Instruments and Measurements 1113 Electrolytic Hygrometers The dampness, and therefore the electrical resistance of a salt film, varies with the humidity of the atmosphere to which the film is exposed, and at least two types of instruments based , on this fact have been developed. The Dunmore hygrometer was originally designed for use in radio-sondes or small 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 hygrometer consists of a dual, winding.of small wire, on a non-conducting tube. The whole is coated with an electrolytic film, usually containing a salt such as lithium chloride, which forms an electric connec tion between the windings. Means are provided for determining the.elec trical resistance of the film, which is an indication of the humidity. In the radio-sonde, variations in the resistance of the film affect the frequency of an oscillating circuit. These hygrometers are usually calibrated by com parison with a wet- and dry-bulb psychrometer. For calibration for some purposes, particularly for use at sub-zero temperatures, means have been provided for producing atmospheres of known humidity.43 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 elec trode 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 alter nately exposed to the test gas, and to a standard gas having a known abso lute 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 on 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 labora tory work, powerful desiccants such as sulphuric 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.44 HEAT TRANSFER THROUGH BUILDING MATERIALS Thermal Conductivity Use of the guarded hot plate apparatus for determining the thermal con ductivity (k value) of homogeneous materials was adopted by A.S.H.Y.E. ln UU2, and has become practically universal, and the apparatus is de scribed in an A.S.T.M. publication.45 * 46 It consists essentially of an elecrically heated plate and two water cooled plates. Two identical speci mens 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 outside m each specimen by a clamp screw. Hot plate apparatus accommodating Pecimens on the order of one foot square and an inch or more thick, is 1114 CHAPTER 51 1954 Guide common. The apparatus at the National Bureau of Standards takes speci mens 8 in. square, while plates as large as 3 ft square have been used. The heated plate is divided into two portions: the central or measuring section, and the outer or guard section. During tests the two sections are main tained as nearly as possible at the same temperature, and the purpose of the guard section is to minimize errors due to edge effects. The electric energy required to heat the measuring section is carefully observed and, converted to Btu per hour, is divided by the area and the temperature gradient to obtain the conductivity of a material tested. 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 complicated by the inclusion of metal, for instance, and tests for conductance are required. The apparatus is required to accom modate large specimens representing actual construction. The shielded hot box apparatus was developed for this purpose.47 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 Built-up Sections, C-236-49T.47 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 side to be placed against the specimen. The cold box is clamped against one side 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 metering box is measured, converted to Btu per hour, and divided by the area and the temperature difference through the wall, from surface to surface, to yield the conductance of the wall. The transmittance or (7-value of the wall is then computed by means of the surface coefficients from Chapter 9. The Nicholls heat flow meter is sometimes useful for measuring steady heat flow through a wall or other building member.48 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 state, the tempera ture difference through the slab, measured with the thermocouples, with the known thermal resistance of the slab, indicates the 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., ,. EVALUATION OF THE THERMAL ENVIRONMENT Advocates of radiant heating emphasize the fact that comfort depends on radiant heat exchanges, as well as air temperature. For this reason sev eral instruments have been devised to evaluate the comfort or warmth of rooms, taking radiant as well as convective effects into account. Prom inent among these are the eupatheoscope, the globe thermometer, the thermal integrator and the heated globe.49' 50 Descriptions are contained in the references, and are omitted here because these devices are not widely used in America for several reasons, among which is the fact that radiant Instruments and Measurements 1115 heating with high temperature sources is not a chief method of comfort heating in this country. 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 calori metric test consists in measuring 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.51 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.62 A heat balance consists 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. ' 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 unaccounted for factor.62 Flue Gas Analysis 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 ex tracted 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 pyrogal- late 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 carbon dioxide value obtained. More elaborate labora tory equipment is sometimes provided for precise determination of carbon monoxide content by burning the carbon monoxide to carbon dioxide in presence of a catalyst.53-64 In large plants, carbon dioxide recorders are used to obtain a continuous indication of the plant's efficiency.55 SMOKE DENSITY MEASUREMENTS Rvngelmann charts are widely used for evaluating the density of smoke cuscharged from chimneys or stacks, and smoke ordinances are based on nem m some cities. Each chart is composed of a series of crossed black whi*'e paper which, at a distance of about 50 ft, is visually compared tn the smoke under observation. Four charts are used with different egrees of blackness as shown in Table 1. The smoke density is specified y Bmgelmann numbers from 1 to 4. The photoelectric cell is used in some apparatus developed for smoke ensity recording in large plants. The same device is included in the test- g equipment for domestic oil burners described in National Bureau of n,7hr Commercial Standard CS75-42.58 Under Laboratory Tests this co (!Ca^I.on cntains the following section: "Smoke Determination.--After ^mtmstion has reached equilibrium, the amount of smoke in the flue gases, erl.vi<-wed lengthwise through 4 feet of the smoke pipe in accordance with Underwriters' Laboratories, Inc., Standard for Domestic Oil Burners 1116 CHAPTER 51 1954 Guide Table 1. Ringelmann Smoke Chart Spacings ' Number of Card Thickness op Lines, mm Distance in Clear Between Lines, mm : I ------2 3 4 1.0 2.3 3.7 5.5 9.0 7.7 6.3 4.5 (Subject 296), March 1934 and subsequent revisions, shall not reduce the output of a standard photoelectric 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, the burner shall operate with out visible smoke at the chimney top. A method of evaluating smoke produced by pot type oil burners was developed for the Institute of Cooking and Heating Appliance Manufac turers by R. N. St. John. A glass rod is interposed between a light source and a photo-sensitive cell, both before and after being exposed to the flue 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 emf 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 CS104-46.62 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 blackness charts or with spots from other sources. For counting, particles are captured in a device such as the SmithGreenbiirg impinger, the Owens jet dust counter, or in an electrostatic or a thermal precipitation device designed for the purpose.67 Counting is done with a microscope, 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 thimble dining the operation is the weight of the dust captured from the air sample.68 For precise work, the thimble must be dried in a desiccating chamber before weighing each time. The test method specified in the A.S.H.V.E. Code for Testing and Rating Air Gleaning Devices Used in General Ventilating Work is based on a weight method for evaluating the cleanliness of air after pass ing through an air cleaner.69 The Code has not filled all needs for an air cleaner testing method and the subject is now under investigation by the A.S.H.V.E. Research Laboratory. At the National Bureau of Standards a test method was developed for interested Government agencies, under which measured samples of the un cleaned air and of the air cleaned by a device under test are passed through filter papers.60 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 photometer. The ratio of the flow rate 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 meaningless unless the test dust is specified. Other instruments for determining gaseous Instruments and Measurements 1117 and particulate air contaminants are described in industrial hygiene litera ture.67-61 62 63 Sound and Vibration Measurements ,' . Approximate measurements of sound intensity can be made by aural methods. The ear is used to compare the measured noise with sounds of known strength. Electrical devices, in which the ear plays no part, furnish the most satis factory means of measuring noise intensities. The sound meter consists essentially of a microphone coupled to an amplifier designed with an ear-like response. The output of the microphone is read on a sensitive direct current milliammeter graduated to read directly in decibels. Instruments of this type, if connected with suitable band pass filters, can be used to study the intensity of the sound over its entire range of frequencies. : Electrical instruments are available for measuring the frequency, ampli tude and acceleration of a vibrating mass. They are usually more con venient and accurate than the vibrating reed tachometer, the seismic type displacement meters or the accelerometers which can also be used for this purpose. Sound level meters are discussed in several text books64'66 and standards.66 . REFERENCES Standard Code for Testing and Rating Steam Unit Beaters, adopted January, 1930, by A.S.H.VJE. revised 1950. ' '. ' ' " * A.S.H.V.E. Standard Code for Testing and Rating Steam Unit Ventilators (A.S.H.VJE. Transactions, Vol. 38, 1932, p. 25), adopted June, 1932. ' -. ' . 1 A.S.R.E. Standard Methods of Rating and.Testing Air Conditioning Equipment, A.S.R.E. Circular No. 13. '' 4 A Survey of Testing Methods and Rating Limits for Domestic Heating Devices, by R. S. Dill (A.S.H.V.E. Transactions, Vol. 51, 1945, p. 185). ' ' ' * For a comprehensive treatment of temperature measurement the reader is referred to Temperature, Its Measurement and Control in Science and Industry, a symposium sponsored by the American Institute of Physics and published by Reinhold Publishing Corp. ' .- Errors in the Measurement of the Temperature of Flue Gases, by P. Nicholls and W.'E. Rice'(A.S.H.V.E. Transactions, Vol. 35, 1929, p. 473). . 'Temperature Measurement (A.S.M.E. Power Test Code, Part 3). ." ' JLestig8tion of Warm Air Furnaces and Heating Systems, by A. C. Willard, A. P. Kratz and V. S. Day (IUtnois Engineering Experiment Station, Bulletin No. 120). .. 'Measuring Heat Transmission in Building Structures and a Heat Transmission Meter, by P. Nicholls (A.S.H.V.E. Transactions, Vol. 30, 1924, p. 94). ' Parallel-Connected Thermocouples for the Testing of Gas Appliances, by Walter B. Kirk and George J. Pacanovsky (Gas, September, 1939, p. 51). - "American Standard for Indicating Pressure and Vacuum Gages, Round Dial Type, with Elastic Pres sure Chamber, B. 40.1 1939- American Standards Association). at Test Code for Centrifugal and Axial Fans, 1938 (A.S.H.V.E. and N.A.P.M.) published by N.A.F.M. as Bulletin No. 110. u Fan Engineering, Buffalo Forge Company, 5th Edition, p. 165. 14 Illinois Micromanometer (University of Illinois, Engineering Experiment Station Bulletin No. 120,- p. 91). uTbe Weathertightness of Rolled Steel Windows, by J. E. Emswiler SDd W. C. Randall (A.S.H.V.E. Abansactions, Vol. 34, 1928, p. 527). u Pressure Measurement (A.S.MJ3. Power Test Code 1936, Part 2, Chapter 2). ' ''The Measurement of Static Pressure;' by C. J. Fechheimer (Mechanical Engineering, August,. 1927). ' , TJ14 P^hrometric Tables for Vapor Pressure, Relative Humidity and Temperatures of the Dew-Point tu. 6. Department of Agriculture, Weather Bureau, Washington, D. C.). ' '' of datajrefer Tluid Meter Reports, Parts 1--1937, 2--1931, and 3--1933 (American Society 10Technical Notes No. 546 (National Advisory Committee for Aeronautics, November, 1935). (A q Characteristics of Double Pitot Tubes, by F. R. Ingram, E. Diez-Canaeco and L. Silverman .n.v.h,. Journal Section, Heating, Piping and Air Conditioning, November, 1942, p. 708). Coefficients of Square Edged Orifices for Measuring the Flow of Air, by H. S. Bean, E. Buck- g m and P. S. Murphy (Bureau of Standards Journal of Research, Vol. 2, 1929, p'. 501)! " - 1940) ^ow Measurement by Nozzles and Orifice Plates (A.S.M.E. Power Test Codes; Chapter.4 of-Part 5, * Air Flow Measurementin the laboratory, by D. D. Wile (Refrigerating Engineering, June, 1947, p. 515). Research Report No. 1204--Entrainment and Jet-Pump Action of Air Streams, by G. L. uve> u. B. Pnester and D. K. Wright, Jr. (A.S.H.V.E. Transactions, Vol. 48, 1942, p. 241). silti1 il,!;, ini'. i.j t'\ i,! 3:i 0r ,! j! I. !: l , i!, ; ;i j I I. 1118 . CHAPTER 51 1954.Guide * A.S.H.V.E. Research ReportsNcs. 857, 911 and 966---Measurement of the Flow of Air Through Reg isters and Grilles, by L. E. Davies (A.S.H.V.E. Transactions, Vol. 36, 1930, p. 201, Vol. 37, 1931, p. 619, and Vol. 39, 1933, p. 373). n A.S.H.V.E. Research Report No. 1162--Air Flow Measurements at Intake and Discharge Openings and Grilles, by G. L. Tuve and D. K. Wright, Jr. (A.S.H.V.E. Transactions, Vol. 46, 1940, p. 313). n A.S.H.V.E. Research Report No. 1092--The Flow of Air Through Exhaust Grilles,.by A. M. Greene Jr. and M. H. Dean (A.S.H.V.E. Transactions, Vol. 44, 1938, p. 387). .' * A.S.H.V.E. Research Report No. 936--Investigation of Air Outlets in Class Room Ventilation, by G. L. Larson, D. W. Nelson and R. W. Kubasta (A.S.H.V J3. Transactions, Vol. 38, 1932,-p. 463). w A.S.H.VJ2. Research Report No. 1076--Air Distribution From Side Wall Outlets, by D. W. Nelson and D. J. Stewart (A.S.H.V.E. Transactions, Vol. 44, 1938, p. 77). ' *' Measuring Air Flow, by G. L. Tuve (Hating, Piping and Air Conditioning, December, 1941). " A.S.H.V.E. Research Report No. 1140--The Use of Air Velocity Meters, by G. L. Tuve, D. K. Wright, Jr. and L. J. Seigel (A.S.H.VJ3. Transactions, Vol. 45, 1939, p. 645). ` - ** Temperature, Humidity and Air Motion Effects in Ventilation, by O. W. Armspach and Margaret Ingels (A.S.H.V.E. Transactions, Vol. 28, 1922, p. 103). .. M A.S.H.VJ3. Research Report No. 1165--Development of Instruments for the Study of Air Distri bution in Rooms, by A. P. Kratx, A. E. Heraheyand R. B. Engdabl (A.S.H.ViE;-Transactions, Vol. 46, 1940, p. 351). . u Development of Testing Apparatus for Thermostats, by D. D. Wile (A.S.H.V.E. Transactions, Vol. 42, 1936, p. 349). r m The Heated Thermometer Anemometer, by C. P. Yaglou (Journal Industrial Hygiene and Toxicology, Vol. 20, October, 1938, No. 8). . A Simple Heated-Thermocouple Anemometer, by H. B. Nottage(A.S.H.VJ3. Transactions, Vol. 56, 1950, p. 431). ;: ** A.S.H.V.E. Research Report No. 959--Indices of Air Change and Air Distribution, by F. C. Houghten and J. L. Blackshaw (A.S.H.V.E. Transactions, Vol. 39, 1933, p. 261). ' ** Measurement of Ventilation Using Tracer Gas Technique, by J. B. Dick (A.S.H.V.E. Journal Sec tion, Heating, Piping and Air Conditioning, May, 1950, p. 131). "The Temperature of Evaporation, by Willis H. Carrier (A.S.H.V.E. Transactions, Vol. 24, J918, p. 25). 47 Fsychrometric Tables for Vapor Pressure, Relative Humidity and Temperatures of the Dew-Point (U. S. Department of Agriculture, Weather Bureau, Washington, D. C.). * A Review of Existing Psychrometric Data in Relation to Practical Engineering Problems, by W. H. . Carrier and C. O. Mackey (A.S.MJS. Transactions, January, 1937, p. 33; Discussion AJ3.MJS. Transaction*, August, 1937, p. 528). Divided Flow Low Temperature Humidity Test Apparatus, by Arnold Wexler (National Bureau of Standards, Research Paper No. 1894). ' 44 Gas Analysis by Measurement of Thermal Conductivity, by H. A. Daynes (Cambridge Press, 1933). 44 Standard Method of Test for Thermal Conductivity of Materials by Means of the Guarded Hot Plats adopted July, 1942, by A.S.H.V.E. (A.S.T.M. Designation C177 - 42T). ** Guarded Hot Plate Apparatus Complying With the Requirements of Section 4 of A.S.TJd. Method of Test for Thermal Conductivity of Materials by Means of the Guarded Hot Plate, AJS.T.M. 47 Tentative Method of Test for Thermal Conductance of and Transmittance of Built-up Sections by Means of Guarded Hot Box (American Society for Testing Materials, ASTM C-236-49T). ' ' - 44 A.S.H.V.E. Research Report No. 685--Measuring Heat Transmission in Building Structures and a Heat Transmission Meter, by P. Nicholls (A.S.H.VJ3. Transactions, Vol. 30, 1924, p. 65). 4> Instruments and Methods for Recording Thermal Factors Affecting Human Comfort, by C. P. Yaglou, A. P. Krati and C.-E. A. Winslow (Year Book, American Journal Public Health, 36737). M The Thermo-Integrator--A New Instrument for the Observation of Thermal Interchanges, by C.-E. A. Winslow and Leonard Greenburg (A.S.H.V.E. Transactions. Vol. 41, 1935, p. 149). u I => B = R Testing and Rating Codes for Low Pressure Heating Boilers, 1947 (Institute of Boiler and Radiator Manufacturers). - . . 41 Commercial Standard for Warm Air Furnaces Equipped with Vaporising Pot-Type Oil Burners, C-&* 104-46 (National Bureau of Standards). - .. o Rapid Determination of Small Amounts of Carbon Monoxide, by Martin Shepherd (Ind. Eng. ChestAnal. Ed. 19, 77: 1947). 44 Determination of Small Amounts of Carbon Monoxide in Air by Various Reference Methods, by Martin Shepherd (National Bureau of Standards Journal of Research 38,' 351-8; 1947 R. P. 1777).' 44 A Carbon Monoxide Recorder, by S. H. Katz, D. A. Reynolds, H. W. Frevert and J. J. Bloomfield - (U. 8. Bureau of Mines, Technical Paper So. 355, 1926). - 44 Commercial Standard for Mechanical Draft Oil Burners Designed' for Domestic Installations, C-S. 75-42 (National Bureau of .Standard#). . .. - Industrial Dust, by Philip Drinker and Theodore Hatch (McGraw-Hill Book Company, New York)- 44 Testing and Rating of Air Cleaning Devices Used for General. Ventilation Work, by S. R. Le*78 (AAH.V.E. Transactions, Vol. 39, 1933, p. 277). . . . ... 44 A.S.H.V.E. Code for Testing and Rating Air Cleaning Devices Used, in General Ventilation Work, adopted January, 1934 (A.S.H.V.E. Transactions, Vol. 39, 1933, p. 225). 40 A Test Method for Air Filters, by Richard S. Dill (A.S.H.V.E. Transactions, Vol. 44, 1938, p. 379). 41 Analytical Chemistry of Industrial Poisons, Hazards and Solvents, by Morris B. Jacobs (Interscience Publishers, Inc-, New York, 1941). .. 43 The Determination and Control of Industrial Dust, by J. J. Bloomfield and J. M. Dalla Valle (V. & Public Health Bulletin No. 217, 1935). 44 Sampling and Analysis of Atmospheric Contaminants, by F. A. Patty (Industrial Hygiene and Tost cdogy, Vol. I, Interscience Publishers, Inc., New York, 1948). ' 44 Electrical Engineer's Handbook, by Harold Pender and Knox McDvaine (John Wiley and Sons, Ne* York). 44 Elements of Acoustical Engineering, by Harry F. Olson (D. Van Nostrand Co., New York). 44 American Tentative Standards for Sound Level Meters for Measurement of Noise and Other Sounds* Z 24.3-1944 (American Standards Association). CHAPTER 52 CODES AND STANDARDS THE Codes and Standards listed in Table 1 represent accepted practice, methods, or standards prepared and accepted by the organizations in dicated. They are valuable guides for the practicing engineer in determin ing test methods, ratings, performance 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 bt Vabious Societies and Associations Subject Title . Sponsor Acoustics American Standard Acoustical Ter* (Terminology) minology. ' ' AS of A Air Conditioning Air Conditioning (120,000 Btu/ Hr or less) Code of Minimum Requirements for Comfort Air Conditioning (1938)', ' Code and Manual for the Design and Installation of Warm Air Winter Air Conditioning Systems (1945)1 ASHVE V;:" ; ASRB , . NWAH & ACA Air Conditioning The Technical Code for the Design NWAH & ACA (Above 120,000 and Installation of Mechanical Btu/hr) Warm Air Heating Systems (1948), Air Conditioning Standards of the NBF V for the Instal lation of Air Conditioning, Warm Air Heating, Air Cooling and Venti lating Systems. NFPA NBFU Air Conditioning (Equipment) ASRB Standard Methods of Rating and Testing Air Conditioning Equipment (1942). " ' ASRB ASHVE NBMA RMA ACMA ' ASRB Standard Methods of Rating and Testing Air Conditioners (1949). (Supersedes ASRB Circular 13-42), ASRB . Aeronautical Recommended Practice for Heating and Ventilating Air planes (1943). SAB , Attic Ventilation Boilers Boilers Boilers Boilenj Boilers Boilers Aeronautical Recommended Practice for Internal Combustion Type Air plane Heaters (1945). Residence Ventilation Guide (1950). I=B=R Testingand Rating Code for Low Pressure Heating Boilers (1950). Net Load Recommendations for Heat ing Boilers. Publ. semi-annually. Net Square Feet Radiation Loads in 70 Deg Fahr, Recommended for low Pressure Heating Boilers (1948). ' Standard and Short Form Heat Bal ance Codes for Testi ng Low Pressure Steam Heating Solid Fuel Boilers (Codes 1 and 2)(1929). ASHVE Performance Test Code for "tem Heating Solid Fuel Boilers (Code No. 3)(1929). ASHVE Standard Code for Testing Steam Heating Boilers Burning.Cm Fuel (1932). - -SAB ; PPMAIBR . .; HP A ACCNA HP & ACCNA ASHVE ASHVE , ASHVE . im Reference ASA Z24.1 ASHVE NWAH AACA Manual No. 7 3rd Edition NWAH A ACA - .Manual No. 9 4th Edition NBFU Pamphlet No. 90 Feb. 1950 ASRB Circular No. 13-42 ASRB Standard 16-53 SAB ARP 85 SAB ARP 143A PFMA IBR HP A ACCNA HP A ACCNA ASHVE ASHVE ASHVE . i '(![ i i ' ' Kit ! Mi & '! i , !;i ^ if i M]U : i. ' \\ < Hi;1-]: ; ii I ' ! ' r. j; , r 1 :1! 1120 CHAPTER 52 1954 Guide Table 1. Codes and Standards--(Continued) Subject Title Sponsor Reference Boilers ASBVE Standard Code for Testing: Stoker-Fired Steam-Heating Boilers (1938). ' . ASHVE - ASHVE - Boilers ASME Boiler Construction Code for Low Pressure Heating Boilers (1946 . with 1948 Addenda). . ASME ASME Boilers . ASME Boiler Construction Code (Combined Edition) (1946 with 1947 Addenda). ' . ASME - ASME Boilers(Gas) ` American Standard Approval Re1 . uuirementa for Central Heating Gas Appliances Vol. 1,. Steam and Hot ` Water Boilers (1951). A.O A. ' ' ASA Z21.13.M951 Boilers (Miniature) ASME Miniature Boiler Code (1946). ASME ASME Boilers (Power) ASMETower Boiler Code, Including Rules for Inspection (1946) with 1947 Addenda). SMB ASME Boilers (Power) Suggested Rules for Care of Power .. . ASME Boilers (1946). . ASME Boilers (Steel) Steel Boiler Institute Rating Code for - Commercial Steel Boilers and Resi dential Steel Boilers (1948). i SBI. SBI Boilers (Steel) - Simplified Practice Recommendation for Steel Firebox Boilers and Steel . Heating Boilers (Commercial and Residential Types) (1950). BS SBI , . BS R157-50 Boilers (Steel) SBI Code for Testing Oil-Fired Resi dential Steel Heating Boilers (1948)'. SBI SBI Boilers (Steel) . SBI Rating Code for Scotch Type ; Boilers (Over 15 psi Working.Pres sure) (1949). . SBI SBI Building Code Standards Building Code Standards of the NBFU for the Installation of.Heat Producing Appliances, Heating', ' ing. Ventilating, Air Conditioning, Blower and Exhaust Systems. NBFU NBFU Building American Standard Building Re Requirements quirements (1946). NHA . . uspest ASA. :/ . . A53.1-1946 Buildings Basic Building Code (Also published in Abridged form as Abridged Building Code) 1950. BOCA ' BOF Burners (Anthracite) Commercial Standard for Domestic Burners for Pennsylvania Anthra cite (Underfeed Type) (1940). : BS AlL BS CS48-40 Burners (Gas) American Standard Requirements for Installation of Domestic Gas Con version Burners (1948). A.Q.A. ASA Z21.8-1948 Burners (Gas) American Standard Requirements for Installation of Gas Burning Equip ment in Power Boilers (1950). A.G.A ASA Z21.33-1950 Burners (Gas) American Standard Listing Require ments for Gas Conversion Burners (1948). . A.G.A ` ASA Z21.17-1948 Burners (Oil) Commercial Standard for MechanicalDraft Oil Burners Designed for Do mestic Installations (1942). ' ' BS ' OBI BS CS75-42 Chimneys (Flue Linings) Cleaners (Air) American Standard Sizes of Clay Flue Linings (1947). ASHVE Standard Code for Testing and Rating Air Cleaning Devices Used in General Ventilation Work (1934). AIA PC ASHVE ASA A62.4-1947 See ASHVE Trans"; tions, Vol. 39, 19^ p. 225 Cleaners (Air) Code for Testing Air Cleaning Devices Used in General Ventilation: Section I, Unit or Panel Type Air Filtering Devices (1953). AF1 AFI Codes and Standards 1121 Table 1. Codes and Standards--(Continued) Subject Coal (For Stokers) Coils Color Scheme (Piping) Color Scheme (Piping) Compressors Condensers Condensers ' Condensing Units Conductance Conductivity Title Sponsor Tentative Standard Procedure for Testing and Evaluating Bitumin ous Stoker Coals (1952). . SMA BCR Proposed Commercial Standard for BCMI Rating and Testing Air Cooling . ... ..BS - \ Coils Using Non-Volatile Refriger ants (1945). Scheme for Identification of Piping Systems (1945). HP <& ACCNA Scheme for Identification of Piping Systems (1928). ASME ASRE Standard Methods of .Rating, and Testing Refrigerant Com pressors. .ASRE :.. .ASHVE ACRMA ASRE Standard Methods of Rating and Testing Evaporative Conden sers. ,ASRE Standard Methods of Rating and Testing Water-Cooled Refrig erant Condensers. . .' . . -ASRE ASHVE .. ACRMA ASRE ' ASHVE ACRMA ASRB Standard Methods of Rating and Testing Mechanical Condensing. : . Units (1940). ASRE ASHVE ACRMA Tentative Method of Test for Thermal - , Conductance and Transmittance of, - Built-Up Sections by Means of Guarded Hot Box (1949). .. .. ASTM :. Standard Method of Test for Thermal Conductivity of Materials by Means of the Guarded Hot Plate (1945). ASHVE ASRB ASTM NRC Reference SMA BCR i BS TS 4044 HP <fc ACCNA Engrg. Stds., Sec. Part V ASA A13-1928 2 ASRE . Standard 23-R ASRE Standard 20 ASRE Standard 22 ASRB - Standard 14-41 . ASTM C 236-49 T ASTM C-177-45 Control Equip ment (Indus trial) Underwriters* - Laboratories,. Inc., Standard for Industrial Control Equipment (July 1938, reprinted Sept. 1945). ' : : UL: - - UL Subject 508 Controls Controls Temperature Convector Convector Convector Underwriters' Laboratories, Inc., Standard for Temperature Indicat ing and Regulating Equipment (Jan. 1947). - UL NEMA StandardsforAutomaticTem- \ - NEMA perature Controls (1953). ' .' ASHVE Standard Code for Testing and Rating Concealed Gravity Type Radiation(Hot Water Section) (1933). , , ASHVE ASBVE Standard Code for Testing, ; ing and Rating Concealed Gravity Type Radiation (Steam Code) (1931). . 'ASHVE , Commercial Standard for Testing and Rating Convectors (1947). . . V BS . .... CMA . . IBR UL Subject 873 NEMA DC1-1953 . ASHVE Transactions, Vol. 39, 1933, p. 237 ASHVE . Transactions, Vol. 37, 1931. p. 367 . BS C8 140-47 Coolers (Air) Coolers Ducts and Fittings E(HhLTra Exhaust Systems ASRB Standard Methods of Rating and Testing Forced Circulation and Natural Convection Air Coolers for Refrigeration (1945). : ASRE . ` ASHVE ACRMA , .REMA ASRE Standard Methods of Rating and Testing Water and Brine Coolers. " ./.ASRE ASHVE .... ACRMA Simplified Practice Recommendation for Pipes, Ducts and Fittings for Warm Air Heating and Air Condi tioning (1945). ... . Mfrs. BS Standards of Tubular Exchanger Man . ufacturers Association (1941). " TEMA , - American Standard for Grinding, Pol ishing, and Buffing Equipment Sanitation (1941). AFA *' . ASRB ? Standard 25-44 ASRE Standard 24 BS R207-49 TEMA ASA 1122 . CHAPTER 52 > 1954 Guide Tabu: 1.' Codes and Standards--(Continued) Subject Title Sponsob Refebence Exhaust Systems Tentative Code of Recommended ... AFA Practices for Testing and Measur ing Air Flow in Exhaust Systems (1937). . AFA . Preprint 36-27 Exhaust Systems Tentative Recommended Good Prac tice Code and Handbook on the Fundamentals of Design, Construc tion, Operation and Maintenance of Exhaust Systems. AFA AFA Exhaust Systems Standards for Blower and Exhaust Systems (1949). Exhaust Systems American Standard Safety Code for (Open Tanks) Ventilation and Operation of Open- Surface Tanka (1951). . Fans Definitions and Terms in Use by the Blower Industry (1950) (Was NAFM Bulletin No. 105). NFPA : NBFU A1BA A.S.H.V.E. NAFM NAFM NFPA No. 91 ASA Z9.1-1951 NAFM Bulletin No. 110 Fans Fans Standard Test Code for Testing Cen trifugal and Axial Fans (1950) (Was NAFM Bulletin No. 103). . Standard Code for Testing Centrifu gal, Axial, and Propeller Fans- (Hav- ing Wheels Less Than 12-in. Diam). 1953. NAFM* ASHVE - NAFM NAFM ' Bulletin No. 110 NAFM Bulletin No. 116 Fans Fans Fans Fans Standards, Definitions, Terms and Test Codes for Centrifugal, Axial and Propeller Fans. Standards for Fans (1947). Test Code for Fans (1946). Testing and Rating Ventilating Fans (Axial and Propeller Type). ' NAFM ASHVE** NBMA ' - ASMS CSD NAFM Bulletin 110 2nd Edition, 1952 NBMA Publ. 47-128 ASMS PTC 11-1946 CSD Fire Prevention Building Code Recommended by the National Board of Fire Underwriter! (1943). NBFU - NBFU Fire Prevention Fire Prevention Furnaces (Duct) National.Fire Codes (1951). National Fire Code for the Prevention of Dust Explosions (1943). American Standard Approval Re quirements for Gas-Fired Duct Fur naces (1950). ' NFPA NFPA A.G.A. NFPA NFPA ASA Z21.34-R1950 Furnaces (Gas, Floor) Commercial Standard for Gas Floor Furnaces--Gravity Circulating Type (1942). BS AGABM BS CS99-42 Furnaces (Gas) American Standard Approval Re quirements for Central Heating Gas Appliances Vol. II, Gravity and Forced Air Central Furnaces (1952). A.G.A. , Furnaces (Forced Air, Solid-Fuel) Commercial Standard for Solid-Fuel- FHA Buming Forced Air Furnaces (1944). N.W.A.H. A A.G.A. AIL Furnaces (OilFired) Commercial Standard for Warm Air Furnaces Equipped with Vaporis ing Type Oil Burners (1949). Mfrt. BS . Furnaces (OilFired) Recommended Commercial Standard for Warm Air Furnaces Equipped with Pressure Atomising or Rotary Type Oil Burners. BS NWAH & ACA Furnaces (Oil) Commercial Standard for Oil Burn ing Floor Furnaces Equipped with Vaporising Type Burners (1951). BS OPA Furnaces (Oil) A Tentative Code for Testing Oil- Fired Furnaces. . Also endorsed by PFMA. ** Refers to Test Code for Centrifugal and Axial Fans. NWAHAACA ASA Z21.13.2 1951 BS CS109-44 BS CS104-49 BS TS-5107 BS CS113-51 NWAH A ACA Codes and Standards 1123 Table 1. Codes and Standards--(Continued) Subject Title Garage _ Ventilation . Recommended Good Practice Re quirements for the Construction and Protection of Garages (1932). Garages Code of Minimum Requirements for Heating and Ventilating Garages (1935). Gas Equipment American Standard Requirements for (Large Boilers) Installation of Gas Equipment in Large Boilers. Gases (Toxic) and Dust American Standard Allowable Con centration of Harmful Gases: Carbon Monoxide Hydrogen Sulfide -- Carbon di-eulfi.de - Benzene Cadmium . Manganese Chromic Acid and Chromate t Mercury 4 Metallic Arsenic and Arsenie Tri oxide Xylene Lead aad Certain Inorganic Lead . Compounds Toluene Oxides of Nitrogen Methanol Heat Transfer (Walls) Styrene-Monomer Formaldehyde. Methyl Chloride Trichloroethylene - Tentative Method of Test for Ther mal Conductance of and Transmit tance of Built-up Sections by Means of Guarded Hot Box (1949). Heaters (Room, Gas Fired) Homes (Pre fabricated) Mineral Wool Mineral Wool Mineral Wool Motors Motors Panel System (Warm Air) Perimeter (Warm Air Small Pipe) American Standard Approval Re quirements for Gas-Fired Room Heaters (formerly called Space Heaters) (1949 with Addenda 1950). Commercial Standard for Prefabri cated Homes. Commercial Standard for Mineral Wool Insulation for Heated Indus trial Equipment (1949). - Commercial Standard for Mineral Wool Insulation for Low Temper ature Installations (1948). . Recommended Commercial Standard for Industrial Mineral Wool Prod ucts^--All Types--Testing and Re porting (1946). Nema Motor and Generator Stand ards (June 1945). Test Code for Single-Phase Motors (1941). Code and Manual for the Design and Installation of Warm Air Ceiling Panel Systems. . Small Pipe Warm Air Perimeter Heat ing. Perimeter (Warm Air) Warm Air Perimeter Heating. A Tubing (Copper & Brass) Piping Simplified Practice Recommendation for Copper Water Tubes and Brass Pipe. American Standard Code for Pressure Piping (1942, with Supplement No. 2, 1947). Spokbob NFPA NBFU . ASHVE A.G.A. ASA ASTM A.G.A. PHMI BS BS IMW1 BS IMWI 1MWI BS NBMA AIBB NWAH A ACA NWAH A ACA NWAHA ACA Mfrt. BS ASMS ilii MjAjiafcct . Rbfebencb NFPA No. 88 ASHVE ASA Z21.33-1950 . ASA Z37.1-1941 Z37.2-1941 Z37.3-1941 Z37.4-1941 Z37.5-1941 Z37.6-1942 Z37.7-1943 Z37.8-1943 . Z37.9-1943 Z37.10-1943 Z37.11-1943 Z37.12-1943 Z37.13-1944 Z37.14-1944 ASTM C-238-49T ASA Z21.11-1949 BS CS125-47 BS CS117-49 BS C8105-48 BS C8131-46 NBMA 46-102 AIBB Report 502 NWAH A ACA Manual No. 7-A NWAH A ACA Manual No. 10 NWAH A ACA Manual No. 4 BS R217-49 ASA B31.1-1942 1124 CHAPTER 52 1954 Guide Table !. Codes and Standards--(Continued) Subject . Title Sponsor Refekence Piping (Gas) American Standard for Installation of staUation of Gas Piping and Gas Ap pliances in Buildings (1950). A'.G.'A. Pumps ' Hydraulic Institute Test Code for Centrifugal Pumps. Hydraulic In stitute Test Code for Rotary Pumps (1943). HI Radiation (Base I*BR Testing and Rating Code board) for Baseboard Type of Radiation (1950). IBR Radiators Code for Testing Radiators (1927). ASHVE Radiators Simplified Practice Reoommendation for Cast Iron Radiators (1943). IBR : BS . Refrigeration (Equipment) Underwriters' Laboratories, Inc.. Standard for Air Conditioning and Commercial Refrigerating Equip ment (Feb. 1946). VL Refrigeration (Mechanical) American Standard Safety Code for Mechanical Refrigeration (1950). ASRE . Refrigeration Underwriters' Laboratories, Inc., (Unit Systems) Standard for Unit Refrigerating Systems (Feb. 1946). VL - Refrigerators / (Gae-Fired) American Standard Approval Re quirements for Refrigerators Using Gas Fuel (1950). , A.G.A. Refrigerators (Household) American Standard Test Procedures for Household Electric Refriger ators (Mechanically Operated) (1944). ASRB USDA Sound American Standard for Noise Meas (Measurement) urement. AS-of A Sound American Standard for Sound Level (Measuremen t) Meters (or Measurement of Noise and Other Sounds. AS of A Sound American Standard Method for the (Measurement). Pressure Calibration of Laboratory Standard Pressure Microphones. AS of A Sound Sound Measurement Test Code for (Measurement) Centrifugal and Axial Fans (1950) (Was NAFM Bulletin No. 104). - NAFM Space Heaters Commercial Standard for Flue Con nected Oil-Burning Space Heaters Equipped with Vaporising Pot*. Type Burners (1943). WHAM > Stokers Code for Determination of Rated Ca . pacities of Anthracite Underfeed Stokera (1944). * SMA Stokers Code for Determination of Rated Ca pacities of Bituminous Underfeed Stokers (1944); SMA Stokers Recommended Minimum Firebox Dimensions and Base Heights (1944). SMA Stokers - Reoommended Standards Governing Minimum Setting Heights (1944). SMA Tubing (Seam less Copper and Copper Al loy) Simplified Practice Recommendation for Copper and Copper-Alloy Round Seamless Tube (1948). Mfra. BS Tubing (Seam Standard Specifications for Seamless less Copper Copper Water Tube (1951). Water Tube) ASTM ASA ' Z21.30-1950 HI Section F IBR ASHVE BS R174-47 VL Subject 207A ASA B9.1-1950 VL Subject 207C ASA Z21.1&-1950 ASA B38.2-1944 - ASA ' Z24.2-1942 : ASA Z24.3-1944 , ASA Z24.4-1938 NAFM . Bulletin No. 110 1950) BS CS101-43 . SMA SMA SMA . SMA BS R23&-48 1 ASA H23.1-1951 Unfired Pressure Unfired Pressure Vessel Code (1950). Vessels *** Also designated ASRE Circular No. 15. ASMS ASMS Codes and Standards Table 1. Codes and STANi)ARDST CConcluded)j;! s... Subject Unit ileators Unit Heaters Title American Standard Approval Re quirements for Gas Unit neavers (1951). Standard Code for Testing and Rating) ' Steam Unit Heaters (1950). ( Sponsor A.G.Ai ASHVE IVHA Unit Heaters Unit Ventilators Vacuum Pumps Warm Air (Gravity) Water Heaters Water Heaters Water Heaters Water Heaters Wiring Wiring Proposed Standard Code for Testing ; Hot Water Unit Heaters (1942). 'IVHA A.S.H.VJ3. Standard Code for Testing and Rating Steam Unit Ventilators (1934). ' ASHVE A.S.H.V.E. Standard Code for Test ing and Rating Return Line Low Vacuum Heating Pumps (1934). ASHVE Gravity Code and Manual for the De sign and Installation of Gravity Warm Air Heating Systems (1947); NWAH -& ACA American Standard Household Auto matic Electric Storage-type Water Heaters. NBMA American Standard Approval Re quirements for Gas Water Heaters (1952). . A.Q.A. NBMA Standards for Electric Water Heaters (1945). . < NBMA Testing and Rating Hand-Fired Hot Water Supply Boilers (1948).' : FHA Interior Wiring Design for Commer cial Buildings. . AIBB National Electrical Code, Standard of NBFU and NFPA (1947, with 1949 Supplement). NBPV NFPA . Reference ASA Z21.lft.lQ51 ASHVE IVHA . Bulletin 10 . IUHA ASHVE ASHVE NWAH A ACA ,t Section No. 5 ' 4th Edition, ASA C72.1-1949 ASA Z21.10-1950 NBMA . 45-104 CS145-47 . AIBB 7 NBFU Pamphlet No. 70 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.Q.A. AGAEM AlA AIEE AlHA AIL ARI ASA AS of A ASHVE ASMS A SRB ASTit BCR BOCA BOP BS CSD CM A fha oama Air Conditioning Manufacturers Association, superseded 1540 by ACRMA. Air Conditioning and Refrigerating Machinery Association, Southern Bldg., Wash ington, D. C. superseded 1953 by ARI. _ American Foundrymen's Association. 16 S. Michigan Ave.,/Chicago, 111. Air Filter Institute, 215 Central Ave., Louisville, Ky. American Gas Association, 420 Lexington Ave., New York, N. Y. Association of Gas Appliance and Equipment Manufacturers, superseded 1945 by GAMA. . American Institute of Architects, 1741 New York Ave., Washington, D. C. American Institute of Electrical Engineers, 33 West 39th St., New York 18, N. Y. American Industrial Hygiene Association, 4400 Fifth Ave., Pittsburgh 13, Pa. Anthracite Industries Laboratory; 237 Old River Rd., Wilkes Barre, Pa. Air-Conditioning and Refrigeration Institute, 1346 Connecticut Ave., N. Washington, D. C. American Standards Association, 70 East 45th St., New York, N. Y. - W Acoustical Society of America, 919 N. Michigan Ave., Chicago, 111. American Society of Heating and Ventilating Engineers, 62 Worth St., New York 13. N. Y. .' American Society of Mechanical Engineers, 29 West 39tb St., New York, N. Y. American Society of Refrigerating Engineers, 40 West 40th St., New York, N. Y. American Society for Testing Materials, 1916 Race St., Philadelphia, Pa. Bituminous Coal Research, Inc., 2609 First National Bank Bldg., Pittsburgh 22, Pa. Building Officials Conference of America, 51 East 42nd St., New York 17, N. Y. Building Officials Foundation, 51 East 42nd St., New York 17, N. Y. National Bureau of Standards, Washington, D. C. _ Commodity Standards Division, D. S. Dept, of Commerce, Washington, D. C. Convector Manufacturers Association, 400 W. Madison Ave., Chicago, HI. Federal Housing Administration, Washington, D. C. Gas Appliance Manufacturers' Association, 60 East 42nd St., New. York, N. Y- 1126 . CHAPTER 52 1954 Guide ABBREVIATIONS AND ADDRESSES (Concluded) HI HP <k ACCNA IBB 1CHAM IMPI imwi IUHA NAPM NBPU NEMA NPPA NHA NBC NWAH <ffc ACA OBI OBIA OPA PC PPMA PHMI REMA RMA SAE SBI SMA TEMA UL USDA . USPH3 Hydraulic Institute, 90 West St., New York, N. Y. Heating, Piping and Air Conditioning Contractors National Association, Suite 1841 30 Rockefeller Plaza, Ndw York 20, N. Y." ,^ Institute of Boiler and Radiator Manufacturers, 60 East 42nd St,, New York, 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 IMPI. Industrial Unit Heater Association, 2157 Guardian Bldg., Detroit, Mich. National Association of Fan Manufacturers, 2159 Guardian'Bldg;, Detroit, Mtih* National Board of Fire Underwriters, 85 John St., New York, N. Y. National Electrical Manufacturers Association, 155 East 44th St., New York,' N. Y. National Fire Protection Association. 60 Batterymarch St., Boston, Mass. National Housing Agency, Washington, D. C. National Research Council, 2101 Constitution Ave., Washington, D. C.' 1 '' National Warm Air Heating and Air Conditioning Association, 145 Public Square, Cleveland, Ohio. Oil Burner Institute, superseded 1942 by OHIA Oil Heat Institute of America,'.Room 1618 (Lower Level) 500 Fifth Ave., 'New York 38, N. Y. . Office of Price Administration,- Washington, D. C. - . . Producers Council, 815-15th St., N.W., Washington, D. C. Propeller Fan Manufacturers Association, 2159 Guardian Bldg., Detroit, Mich. Prefabricated Home Manufacturers Institute, 908 20th St., N.W., Washington, D. C. Refrigeration Equipment Manufacturers Association, superseded 1953 by ABI. Refrigerating Machinery Association. See ACRMA. . Society of Automotive Engineers, 29 West 39th St., New York, N. Y. , /,/ Steel Boiler Institute, 1308 Land Title Bldg., Philadelphia 10, Pa. Stoker Manufacturers Association, 307 N. Michigan Ave., Chicago, 111. . Tubular Exchanger Manufacturers Association, 366 Madison Ave., New York, N. Y Underwriters' Laboratories, 207 East Ohio St., Chicago, 111. United States Department of Agriculture, Washington, D. C. ` United States Public Health Service, Washington, D. C. ' Heating Ventilating Air Conditioning Guide 1127 Materials SPECIFIC HEAT Table 1. Specific Heat of Solids* . FTemperature Specific Heat Authobitt Alloys Brass, Yellow......................................... Atuuunu Fire*Clay Brick...................................... Glass Rocks ' Silica Brick .............................................. Woods (Average)....................................... . 32 32 57-208 68-2370 . 80-212 68-208 104-1637 . 64-212 77-1832 50-122 50-122 64 32 -40 32 32-600 68-212 59-212 32 32 58-212 63-210 54-212 59-212 32-212 32 240-320 77-1832 77 68 32 . 0.0899 0.0883 0.0862 0.127 0.212 0.195 0.195 0.314 : 0.278 0.201 0.270 0.0928 0.258 0.161 0.117 0.0312 0.259 0.487 0.434 0.1043 0.127 0.1189 0.1152 0.0297 0.1032 0.2159 0.2 0.0319 0.196 0.192 0.216 0.21 0.22 0.0536 0.1175 0.220 0.263 0.0548 S .. S S S s s s H I H H H S I s s s H 8 S S .M H H S s H H S Ss . s s s s H S I s 8 s Table 2. Specific Heat of Liquids Liquid Temperature F Specific Heat Authobitt Alcohol. Ethvl dvcerinp Lead (Molten! Mercurv.. Petroleum............ Sea Water Sp Gr 1.0043....... Sp Gr 1.0463................... ^ater... ---- . 32 59-122 360 68 70-136 64 64 59 ! 0.548 0.601 0.576 . 0.041 0.03325 0.511 0.980 0.903 1.000 Table 3. Specific Heat of Gases and Vapors S S s H S S s s s Substance Temperatube F Specific Heat at Constant Pressure Ratio of Specific Heat Cp/Cv Air... Ammonia ~arLon Monoxide.. Coal Gas flue Gas Hjdrogen.. N itrogen... l^*Vgen........... S'er Vapor ....... "ater Vapor ' 80-392 52-417 79-388 68-1900 70-212 212*"* 356 0 ??75 6.5358 0.2169 0.2426 0.3145 0.24 (Approx.) 3.41 0 2175 0.421 0.51 1:8? 1.3003 1.395 1.419 1*3977 1.305 Specific Heat at Constant Volume (Computed) Authobitt 0.419 0.1668 0.1736 2.402 0.1729 0.322 S S S sS H S s s ss (4 q Specific Heat of Thermal Insulating Materials, by Gordon B. Wilkes and Carl O. Wood NcirnrwTRANBAC,noN8. Vol. 48, 1942, p. 493). , .,, Boeeifi* til, iT^n one temperature is given the true specific heat is given, otherwise the value is the mean between the given limits. . Ventilat;^11^1*^^111^*19011^11 Physical Tables, 1933; I--International Critical Tables; H--Heating, Lionel S. M^ks Au> Conditionill8- by L. A. Harding and A. C. Willard; M--Engineers' Handbook, by Table 4. Circumferences and Areas of Circles T)mu. ETEB IN Inches Abba . Sq In. SqFt CIRCUMFERENCE Inches Feet DIaueiEE Inches Abba Sq In. Sq Ft Circumference Inches Feet; y* Yt K 1 IK IH IK 2 2H 2Ys 2H 3 3H 3H 3H 4 4H 4H 4H 5 5M 5H. 5H 6 m 6}* 6K 7 7H m 7H 8 SM m. m 0 9H m m 10 10}* ii \m 12 12 }* 13 13 Vi 14 14}* 15 15H 16 16}* 17 17}* 18 18}* 19 im 20 20}* 21 21 ft 22 22}* 23 23}* 24 24H 25 25}* 26 26}* .27 27}* 0.049 0.0003 0.785 0.196 0.0014 1.571* 0.442 0.0031 2.356 0.785 0.0054 3.142 . 1.227 0.0085 . 3.927 1.767 0.0123 4.712 2.405 0.0167 ' 5.498 . 3.142 0.0218 *' 6.283 3.976 0.0276 ' 7.069 4.909 0.0341 ; 7.854 5.939 0.0412 8.639 7.069 0.0491 9.425 8.296 0.0576 .10.21 9.621 0.0668 10.99 11.04 0.0767 11.78 12.57 0.0873 12.57 14.19 0.0986 13.35 15.90 0.1104 14.14 17.72 0.1231 . 14.92 19.64 0.1364 . 15.71 21.65 0.1504 16.49 23.76 0.1650 17.28 25.97 0.1840 . r;'18.06 28.27 0.1964 7 18.85 30.68* 0.2131 19.64 33.18 0.2304 .20.42 35.79 0.2486 21.21 . 38.49 0.2673 .21.99 41.28 0.2867 . 22.78 44.18 0.3068 23.56 47.17 0.3276 24.35 50.27 0.3491 ; 25.13 53.46 0.3713 25.92 56.75 0.3942 26.70 60.13 0.4175 ,27.49 : 63.62 0.4418 28.27 - 67.20 0.4668 -,29.06 70.88 0.4923 29.85- 74.66 0.5185 . 30.63 78.54 0.5454 31.42 86.59 0.6010 32.99 95.03 0.6600 - : 34.56 103.9 0.7215 36.13 113.1 0.7854 37.70 122.7 0.8520 39.27 ' 132.7 0.9218 . 40.84 143.1 0.9937 .42.41 153.9 1.069 43.98 165.1 1.146 ,45.55 176.7 1.227 47.12 188.7 1.310 48.69 201.1 1.396 50.27 213.8 1.485 51.84 226.9 1.576 53.41 240.5 1.670 54.98 254.5 1.767 56.55 268.8 1.867 58.12 283.5 1.969 ; 59.69 298.6 2.074 61.26 314.2 2.182 62.83 330.1 ' 2.293 64.40. 346.4 '2.405 65.97 .. 361.1 2.508 67.54 380.1 2.640 69.12 397.6 2.761 70.69 415.5 1 ' 2.885 72.26 433.7 3.012 73.83 : 452.4 3.142 75.40 471.4 3.274 76.97 490.9 3.409 78.54 . 510.7 3.547 80.11 530.9 3.687 81.68 551.6 3.832 83.25 572.6 3.976 84.82 593.9 4.125 86.39 . 0.0652 0.1309 o.idfc 0.2618 0.3273 0.3927 0.4582 0.5236 0.5891 0.6546 0.7200 0.7854 0.8510 0.9160 0.9818 1.047 1.113 1.178 1.243 1.309 1.374 1.440 .1.505 1.571 1.637 1.702 1.768 1.833 1.899 1.964 2.029 2.094 2.160 2.225 2.291 2.356 2.422 2.488 2.553 2.618 2.750 '2.880 3.011 3.142 3.273 3.403 3.535 3.665 3.796 3.927 4.058 4.189 4.321 4.451 4.582 4.712 4.845 4.974 5.105 5.236 5.367 -5.498 5.629 5.760 5.891 6.021 6.153 6.283 6.415 6.545 6.676 6.807 6.938 7.069 7.199 28 28}* 29 29}* . 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 .48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 . 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 . 86 . ..87. . . 88 : 89 90 91 92 93 94 95. - 96 97 98 99 100 616.8 4.276 637.9 4.430 660.52 4.587 683.5 4.747 706.8 4.909 754.8 5.241 804.3 5.585 855.3 5.940 907.9 6.305 962.1 6.681 1018.0 7.069 1075.0 7.467 1134.0 7; 876 1195.0 8.296 1256.0 8.727 1320.0 9.168 1385.0 9.621 1452.0 . 10.08 1521.0 10.56 1590.0 11.04 1662.0 11.54 1735.0 12.05 1810.0 12.51 1886.0 13.09 1963.0 13.64 2043.0 14.19 2124.0 14.75 2206.0 15.32 2290.0 15.90 2376.0 16.50 2463.0 17.10 2552.0 17.72 2642.0 18.35 2734.0 18.99 2827.0 19.63 2922.0 20.29 3019.0 20.97 3117.0 21.65 3217.0 22.34 3318.0 23.04 3421.0 23.76 3526.0 . 24.48 3632.0 25.22 3739.0 25.97 3848.0 26.73 3959.0 27.49 4072.0 .28.27 4185.0 29.07 4301.0 29.87 ' 4418.0 30.68 4536.0 31.50 4657.0 32.34 4778.0 33.18 4902.0 34.04 5027.0 34.91 5153.0 35.78 5281.0 36.67 6411.0 .37.57 5542.0 38.48 5675.0 39.41 5809.0 40.34 5945.0 41:28 6082.0 42.24 6221.0 43.20 6362.0 44.18 6504.0 45.17 6648.0 i 46.16 6793.0 47.17 6940.0 . 48.19 7088.0 49.22 7238.0 50.27 7390.0 51.32 7543.0 52.38 7698.0 53.46 7854.0 54.54 87.97 89.54: 91.11 92.63 94.25 97.39 100.5 103.7 108.8 109.9 113.1 116.2 119.4 122.5 125.6 128.8 131.9 135.1 138.2 141.4 144.5 147.7 150.8 153.9 157.1 160.2 163.4 166.5 169.6 172.8 175.9 179.1 182.2 185.4 188.5 191.6 194.8 197.9 201.1 204.2 207.3 210.5 213.6 216.8 219.9 223.1 226.2 229.3 232.5 235.6 238.8 241.9 245.0 248.2 251.3 254.5 257.6 260.8 263.9 267.0 220.2 273.3 276.5 279.6 282.7 286.9 289.0 292.2 295.3 298.4 301.6 304.7 307.9 311.0 314.2 7.330 7.462 7.592 7.725 7.854 8.116 8.378 8.639 8.901 : 9.163 9.425 9.686 9.948 10.21 10.47 10.73 10.99 11.26 11.52 11.78 12.04 12.30 12.57 12.83: 13.09 13.35 13.61 13.88 14.14 14.40 14.66 14.92 15.18 15.45 15-71 15.97 16.23 16.49 16.76 17.02 17.28 17.54 17.80 18.06 18.33 18.59 18.85 19.11 19.37 19.63 19.90 20.16 20.42 20.68 20.94 21.21 21.47 21.73 21.99 22.25 22.51 22.78 23.04 23.56 23.82 24.09 24.35 24.61 25.13 25.39, 25.92 EDGE INDEX for HEATING VENTILATING AIR CONDITIONING GUIDE 1954 Chapter No. Title Index-Technical Data Section 1 Terminology 2 Abbreviations and r Symbols 3 Thermodynamics 4 Fluid Flow Chapter Page No. Title Page ix 27 Pipe, Fittings, Welding 605 1 -28 Pipe Insulation 625 11 29 District Heating 641 23 30 Central Systems for Air Conditioning 653 67 31 Air Distribution 667 5 Heat Transfer 89 32 Air Duct Design 697 6 Physiological Principles 111 ' 7 Air- Conditioning in the Prevention and Treatment of Disease 131 8 Air Contaminants 151 0 Heat Transmission _ Coefficients of Building Materials 10 Water Vapor and Condensation in Building Construction 167 201 11 Infiltration and Ventilation 217 33 Fans 733 34 Air Cleaning 751 35 Spray Apparatus 773 36 Air Heating and Cooling Coils 799 37 Refrigeration 823 38 Dehumidification by Sorbent Materials 861 12 Heating Load 239 39 Automatic Controls 87J 13 Cooling Load 265 40 Motors and Motor Controls 889 14 Fuels and Combustion 321 41 Sound Control 905 lfi Automatic Fuel Burning ' Equipment 357 16 Heating Boilers, Furnaces, SpaceHeaters 385 17 Chimneys and Draft: Calculations 411 18 Estimating Fuel Consumption for Space Heating 433 19 Gravity Warm Air. Systems 451 - 42 Electric .Heating 927 43 Corrosion and Water ' Formed Deposits, Causes and Prevention 945 44 Owning and Operating Costs 967 45 Industrial Air. Conditioning 977 46 Industrial Exhaust Systems 1003 20 Forced Warm Air Systems 461 47 Industrial Drying Systems 1023 21 Steam Heating Systems 481 48 Transportation Air Conditioning 22 Hot Water Heating Systems 523 49 Water Services 1051 1067 23 Radiatms and Convectors 541 24 Panel Heating 553 25 Unit Heaters and Unit Ventilators . 576 60 Residential Summer Air Conditioning 1091 51 Instruments and Measurements 1099 52 Codes and Standards 1119 26 Unit Air Conditioners and Unit Air Coolers 591 Tbs first few times you use this- EDGE INDEX? follow the "HOW TO USE" i slowly and one step at a time. After you will be able to open easily almost instantly to the chapter an ject you are seeking. HOW TO VSEp 1. Place the four fingers of your left (palm up) between the fronts and the front page. 2. Place your left thumb near tbs ' of the open side of this insert.^ 3. Lift your left hand (about 3, " moving it to the right to ben' pages nearly double. From the 1 or 2 line symbol adj to the letter or subject.you e_.... your eye across the page edges'^ you reach the horizontally^ sponding symbol. 4. Open there. There are two rows of symbobjui page edges. The first or left! Identifies the subjeets in the left} row on thTM page. The second .ori hand row identifies the subjects.!? right hand column on this insert^ Page numbers are included if you to use them. You will find it easier and quicker# "fan" or "riffle" the last few peg your left thumb. 1130 THE GUIDE A distinctly new service was inaugurated by the Society in 1922 when it estab lished The Guide. Now in 1954, as the 32nd Edition of the Heating Ventilating Air Conditioning Guide makes its appearance, it is notable that The Guide served effectively not only the membership but the entire profession and the alliei industries, and has received world wide recognition as a reliable and author!tativ compendium of useful heating, ventilating and air conditioning data. Throughout over three decades of service The Guide has become a reference boo| of unchallenged position in its special field of engineering. The intention of its founders, 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 concerning modem equipment, has' been carefully safeguarded by those responsible for the compilation of each Edition 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. INDEX TO ADVERTISERS PAGE 1133 INDEX TO MODERN EQUIPMENT PAGE 1141 INDEX TO MODERN EQUIPMENT PAGE 1141 INDEX TO ADVERTISERS IftHEATING VENTILATING AIR CONDITIONING GUIDE, 1954 A Page fACME INDUSTRIES, INC., Jackson, Mich............................................................ 1300 j-AERCO CORP., 214 Lafayette Place, P. O. Box 428, Englewood, N. J............... 1515 ?AEROFIN CORP., 410 S. Geddes St., Syracuse 1, N. Y.....................1301-1302-1303 AIR & REFRIGERATION CORP., 439 Madison Ave., New York 22, N. Y........ 1171 1'!AIR CONTROL PRODUCTS, INC., Coopersville, Mich...............1368-1369-1370-1371 AIRDEVICES, INC., 185 Madison Ave., New York 16, N. Y...........................1261, 1372 AIR FILTER CORP., 108G N. Water St., Milwaukee 2, Wis............................... 1264 AIR-MAZE CORP., 25000 Miles Rd., Cleveland 28, Ohio..............................1262-1263 $AIRTHERM MFG. CO., 728 S. Spring Ave., St. Louis 10, Mo............................. 1229 ALADDIN HEATING CORP., 1111 West Ave. 137, San Leandro, Calif............. 1318 "ALCO VALVE CO., 851 Kingsland Ave., St. Louis 5, Mo..................................... 1410 4`ALDRICH CO., 121 E. Williams St., Wyoming, 111................................................. 1443 J* ALLEN VENTILATOR DIV., PRODUCTION PLANNING CO., 704 Woodward, V Rochester, Mich.......................................... 1358 AMERICAN AIR FILTER CO., INC., 673 Central Ave., Louisville 8, Ky....... ' 1265-1266-1267 f:AMERICAN ARTISAN (publication), 6 N. Michigan Ave., Chicago 2, HI........ 1610 '> AMERICAN BLOWER CORP., P. O. Box 58, Roosevelt Park Annex, Detroit 32, g.' Mich.. 1172-1173 "AMERICAN BRASS CO., THE, Waterbury 20, Conn......................................1256-1257 AMERICAN COOLAIR CORP., 3604 Mayflower St., Jacksonville 3, Fla............. 1319 AMERICAN DISTRICT STEAM CO., INC., North Tonawanda, N. Y.... .1402-1403 AMERICAN FLANGE & MFG. CO., INC., 30 Rockefeller Plaza, New York 20, ii;' N. Y. . 1601 ? AMERICAN FOUNDRY & FURNACE CO., P. O. Box 904, Bloomington, 111. i' 1214-1215 AMERICAN FURNACE CO., 1300 Hampton Ave., St. Louis 10, Mo.................. 1216 AMERICAN GILSONITE CO., Salt Lake City, Utah........................................... 1571 AMERICAN MOISTENING CO.,Providence 1, R. 1............................................. 1174 ^AMERICAN RADIATOR & STANDARD SANITARY CORP., P. O. Box 1226, . ' Pittsburgh 30, Pa..................................................................................................1444-1445 AMERICAN SOCIETY OF REFRIGERATING ENGINEERS, 40 West 40th 4 St., New York 18, N. Y........................................................................................... 1606 ,AMERICAN-STANDARD, SUNBEAM AIR CONDITIONER DIVISION, Svi. Elyria, Ohio........................................................................................................ 1194-1195 V. D. ANDERSON CO., THE, 1960 West 96th St., Cleveland, Ohio............. 1534-1535 MPAOSTAT CORP. OF AMERICA, 10 East 39th St., New York 16, N. Y.. 1374-1375 1133 1134 1954 APRIL SHOWERS CO., INC., 4126 Eighth St., N.W., Washington 11, D. C... . ARMSTRONG CORK CO., Building Materials Div., Lancaster, Pa................... 1 ARMSTRONG MACHINE WORKS, 851 Maple St., Three Rivers, Mich... 1536-153 ATLAS MANUFACTURING CO., Eustis at Robbins, St. Paul, Minn............... 1538 AUER REGISTER CO., THE, 6600 Clement Ave., Cleveland 5, Ohio............... 13" AURORA PUMP CO., SUB. of the NEW YORK AIR BRAKE CO., 40 Loucks St., Aurora (Chicago Suburb), 111............................ .......................................... AUTOMATIC BURNER CORP., 1823 W. Carroll Ave., Chicago 12, 111............. AUTOMATIC GAS EQUIPMENT CO., Brushton & Thomas St., Pittsburgh 21, Pa...................................................................................................................... . - B *' BABCOCK & WILCOX CO., THE, 161 East 42nd St., New York 17, N. Y....... 1 BADGER MFG. CO., 230 Bent St., Cambridge 41, Mass..................................... 1404 BAHNSON CO., THE, Winston-Salem, N. C.................................................... 1176-1#E BALTIMORE AIRCOIL CO., INC., 2615 Mathews St., Baltimore 18, Md....... 1289 BARBER-COLMAN CO., 150 Loomis, Rockford, 111....................................... 1376, 141 BARNEBEY-CHENEY CO., Cassady & 8th Aves, Columbus 19, Ohio..........1268-1269 BARNES & JONES, INC., 128 Brookside Ave., Boston 30, Mass...................... 153' BARRY CORP., THE, 714 Pleasant St., Watertown 72, Mass.............................. 132 BAYLEY BLOWER CO., 1821 S. Sixty-Sixth St., Milwaukee 14, Wis................. 1321 BELL & GOSSETT CO., Morton Grove, 111...................................................... 1516-151 BINKS MFG. CO., 3130-36 Carroll Ave., Chicago 12, 111..................................1290-1291 BISHOP & BABCOCK MFG. CO., THE, MASSACHUSETTS BLOWER DIV., 4901 Hamilton Ave., Cleveland 14, Ohio........................................................... 132? G. C. BREIDERT CO., 3129 San Fernando Rd., Los Angeles 65, Calif............ 1359 BROOKSIDE PRODUCTS CO., INC., McCordsville, Ind................................. 1323 BROWN PRODUCTS CO., 97-12 Metropolitan Ave., Forest Hills, N. Y......... BRUNDAGE CO., THE, 530 N. Park St., Kalamazoo, Mich................................ 132 BRUNNER MFG. CO., Dept. M-54, Utica, N. Y.................................................... 13j BRYAN STEAM CORP., Chili Pike, Peru, Ind...................................................... 14g BUENSOD-STACEY, INC., 60 East 42nd St., New York 17, N. Y...................... U BUFFALO FORGE CO., 450 Broadway, Buffalo, N. Y........................................... 132 BUFFALO PUMPS, INC., 450 Broadway, Buffalo, N. Y....................................... 1523 BURNHAM CORP., Irvington-on-Hudson, N. Y................................................... 14*l C E. K. CAMPBELL CO., 1809 Manchester, Kansas City 3, Mo........................ . 12J7j CAMPBELL HEATING CO., 3121 Dean, Des Moines 17, Iowa.....................1218-12' CAM-STAT, INC., DIV. of the PAUL HENRY CO., 11831 W. Olympic Blvd., i Los Angeles 64, Calif......................................... ,.................................................. 14)? CAREY ELECTRONIC ENGINEERING CO., Metal Wool Div., 1880 Clifton Ave., Springfield, Ohio.......................................................................................... 12ffl PHILIP CAREY MFG. CO., THE, Lockland, Cincinnati 15, Ohio............... 1580-158 CARRIER CORP., Syracuse 1, N. Y................................................................... 1178-117? CARTY & MOORE ENGINEERING CO., 1150 W. Baltimore Ave., Detroit 2, f Mich........................................................................................................................... 1 CELOTEX CORP., THE, 120 S. LaSalle St., Chicago 3, III..................................... 15CENTURY FAN & VENTILATOR CO., 45 Cedar St., Stamford, Conn............. 13?fe CHAMPION BLOWER & FORGE CO., Div. 9, Lancaster, Pa............................ 13. CHICAGO BLOWER CORP., 9867 Pacific Ave., Franklin Park, 111.................. 1?` CHICAGO PUMP CO., 622 W. Diversey Parkway, Chicago 14, 111...............1524-1525 CHICAGO STEEL FURNACE CO., 9326 S. Anthony Ave., Chicago 17, IU....... 128 CHRYSLER AIRTEMP, DIV. of CHRYSLER CORP., Dayton 1, Ohio . .1196-1197 CLARAGE FAN CO., Kalamazoo, Mich............................................................ 1180, 13 CLEAVER-BROOKS CO., 498 E. Keefe Ave., Milwaukee 12, Wis...............1467, lW COAL-HEAT (publication), 20 W. Jackson Blvd., Chicago 4, 111........................ 1<$ COEN CO., 40 Boardman Place, San Francisco 3, Calif................................:... 14?9 COMBUSTION CONTROL CORP., 718 Beacon St., Boston 15, Mass............... HI? COMBUSTION ENGINEERING, INC., 200 Madison Ave., New York 16, N. Y. & 1468-14<g CONNOR ENGINEERING CORP., Shelter Rock Lane, Danbury, Conn. 1272-1273, 1378-137? aSSpyAdvertisers w 1135 EONTINENTAL AIR FILTERS, INC., P. O. Box 1647, Louisville 1, Ky........... 1271 fcsJANE CO., 836 S. Michigan Ave., Chicago 5, 111............................................. 1448-1449 eURTIS REFRIGERATING MACHINE DIV. of CURTIS MFG. CO., 1959 ` IKienlen Ave., St. Louis 20, Mo.. ......................................................................... 1312 CYCLOTHERM DIVISION, UNITED STATES RADIATOR CORP., Oswego, -N. Y............................................................................................................................. 1470 "i- ' ..y;/ D E BOTHEZAT FANS DIV., AMERICAN MACHINE & METALS, INC., East SMollne, 111................................................................................................................. 1330 DECATUR PUMP CO., 2750 Nelson Park Rd., Decatur, 111................................ 1526 DELTA HEATING CORP., 1 Cole St., Trenton 8, N. J........................................ 1221 CHARLES DEMUTH & SONS, INC., 245 Elm Place, Mineola, N. Y............... 1377 DETROIT STOKER CO., 5-125 General Motors Bldg., Detroit 2, Mich........... 1488 EVICES, INC., 214 East 53 St., New York 22, N. Y.......................................... 1570 WEYrSHEPARD BOILER CO., THE, Sales Office, 1311 N. Capitol Ave., $<Indianapolis, Ind...................................................................................................... 1471 DOLE VALVE CO., THE, 1933 Carroll Ave., Chicago 12, U1................................ 1565 QOLLINGER CORP., 6 Centre Pk., Rochester 3, N. Y....................................1274-1275 DOMESTIC ENGINEERING PUBLICATIONS, 1801 Prairie Ave., Chicago 16, iglU.................................................................................................................... 1608 DQW CHEMICAL CO., Plastics Sales, Midland, Mich........................................ 1589 KAVO CORP., Heating Dept., Dravo Bldg., Fifth & Liberty Aves., Pitts- .sburgh 22, Pa......................................................................................................... 1222-1223 RAYER-HANSON, INC., 3301 Medford St., Los Angeles 63, CaUf....... ......... 1181 C|?A5DUNHAM CO., 400 West Madison St., Chicago 6, IU...................1541-1542-1543 DURANT INSULATED PIPE CO., Demeter St. off Bay Road, Palo Alto, Calif. _ 1572-1573 DURO-DYNE CORP., 38 S. Franklin St., Hempstead, L. I., N. Y...................... 1400 DUTTON BOILERS, DIVISION HAPMAN-DUTTON CO., 639 Gibson St., fJKalamazoo, Mich......................................................................... #" ' 1472 ................... %:- e QONOMY FLUE CLEANER CO., 819-11 Ave. South, St. Cloud, Minn........... IJWNGTON METAL SPECIALTY CO., Eddington, Pa.................................... 9E&7IRDS ENGINEERING CORP., 101 Alexander Ave., Pompton Plains, J............................................................................................................................. AUTO-LITE CO., THE, Instrument & Gauge Div., Dept. HV, -teToledo 1, Ohio.................................................................... .. ... ... HSOTROMODE CORP., 45 Crouch St., Rochester 3,N. Y................................ KHTERPRISE ENGINE & MACHINERY CO., A SUBSIDIARY of GENERAL ^ISETALS CORP., 18th and Florida Sts., San Francisco 10, Calif............... 1494 1505 1414 1253 1507 =& F |45ANKS CO., THE, 393 Lafayette St., New York 3, N. Y............................ 1566 p- - B* 10187, Airport Sta., Los Angeles 45, Calif... .1276-1277 FARRAR &TREFTS, INC., 20 Milbum St., Buffalo 12, N. Y.............................. 1473 Vn?r UIGAN CORP., Hancock & Lalor Sts.,'Trenton 7, N. J................ 1231 ;D CONTROL DIVISION of H. D. CONKEY & CO., Press Bldg., Men- .fir-dota. 111................................... s' 141S boiler CO-.'iNC., ioi Park Ave., New York 17^^.1474-1475 ^`S CORpORATION, CHICAGO METAL HOSE DIVISION, May- CORPORATION, Expansion joint Division, (formerly Chicago Hose Corp.), Maywood, 111......... J.......................... ........... ;........6. 1405 LTD- THE. 2500 S. Atlantic Blvd., Los Angeles 22, Calif....... 1292 FPTni?Vi FEELER CORP., 165 Broadway, New York 6, N. Y.......................... 1293 K2?.WaiM8boro-Pa....................................................................................... 1313 SnTM' DIVISION OF GENERAL MOTORS, Dayton 1, Ohio............. 1184 JnPHON DIVISION, ROBERTSHAW-FULTON CONTROLS gg KnoxvUle 1, Tenn..................................................................................... 1416-1417 ft. g^MANOFACTUMNG CO., THE, 138 Winchester Ave., New Haven 8, GApt.^?.? *=0-> THE, 4108 Dodge Sti, Omaha 3, Nebr.V....... ............ 1360 k^DEN CITY FAN CO., 332 S. Michigan Ave., Chicago 4, 111.......................... 1331 GENERAL AUTOMATIC PRODUCTS CORP., 2300 Sinclair Lane, Baltimore 13, Md....................................... ................................................................................ GENERAL BLOWER CO., 8602 Ferris Ave., Morton Grove, 111 GENERAL CONTROLS, SOI Allen Ave., Glendale'!, Calif............................1418-141'. GENERAL ELECTRIC CO., Air Conditioning Div., Bloomfield, N. J......... 1182-11 GLASFLOSS CORP., 15S East 44th St., New York 17, N. Y.................................. 12 GLASS FIBERS INC., 1810 Madison Ave., Toledo 2, Ohio.................................. 15 GOODYEAR TIRE & RUBBER CO., INC.; THE, Akron 16, Ohio..................... V GORDON & PIATT, P. O. Box 331, Winfield, Kans............................................. 1 GRINNELL CO., INC., Providence 1, R. 1........................................................ 1232-1" GUSTIN-BACON MFG. CO., 210 West 10th St., Kansas City, Mo.................... 15 HALSTEAD & MITCHELL, Bessemer Bldg., Pittsburgh 22, Pa...................... If HAMMOND BRASS WORKS, Summer Blvd., Hammond, Ind.......................... 156 ARTHUR HARRIS & CO., 210-218 N. Aberdeen St., Chicago 7, 111................... 1 HART & COOLEY MFG. CO., Holland, Mich................................................. 1380-1381 HARTZELL PROPELLER FAN CO., DIV. of CASTLE HILLS CORP., Piqua, " Ohio............................................................................................................................ i; HASTINGS AIR CONDITIONING CO., INC., Hastings, Nebr........................ 11 HAYES FURNACE MFG. & SUPPLY CO., 2929 S. Fairfax Ave., Los Angeles 16, Calif..................................................................................................................... 11 HEATING & PLUMBING EQUIPMENT NEWS (publication), 148 Lafayette St., New York 13, N.Y.......................................................................................... If HEATING and VENTILATING (publication), 148 Lafayette St., New York 13, N.Y............................................................................................................................ 16Q8 HEATING, PIPING and AIR CONDITIONING (publication), 6 N. Michigan _ Ave., Chicago 2, 111....................................... lfl HENDRICK MFG. CO., 48 Dundaff St., Carbondale, Pa................................1382-1; HENRY VALVE CO., Melrose Park, 111................................................................... I HLRSCHMAN-POHLE CO., INC., 200 Lent Ave., Le Roy, N. Y........................ 13j5 HOFFMAN SPECIALTY MFG. CORP., 1001 York St., Indianapolis 7, if Ind.......................................................................................................1544-1545-1546-154 HUBBELL CORP., P. O. Box 700, Hawley Road, Mundelein, 111........................ 142 HUNTER FAN AND VENTILATING CO., P. O. Box 2858, Desoto Sta., 400 S. Front St., Memphis 2, Tenn................................................................................. 1. ILG ELECTRIC VENTILATING CO., 2880 N. Crawford Ave., Chicago 41, XU..........................................................................................................................1234, 1 ILLINOIS ENGINEERING CO., Chicago 8, 111................................................1548-1', ILLINOIS TESTING LABORATORIES, INC., Room 516, 420 N. LaSalle St., Chicago 10, 111.......................................................................................................... 142 INDEPENDENT REGISTER CO., THE, 3747 East 93rd St., Cleveland 5, Ohio 1 INFRA INSULATION, INC., 525 Broadway, New York, N. Y.............................. 1 INGERSOLL PRODUCTS DIV., BORG-WARNER CORP., 310 S. Michigan Ave., Chicago 4, 111................................................................................................. 1. INGERSOLL-RAND, 11 Broadway, New York 4, N. Y.................... ................... 1? INSULITE DIVISION, MINNESOTA and ONTARIO PAPER CO., 500 Baker _ Arcade Bldg., Minneapolis 2, Minn.............................................................1590-15? INSUL-MASTIC CORP. OF AMERICA, 1162 Oliver Bldg., Pittsburgh 22, Pa. 1' INTERNATIONAL BOILER WORKS CO., THE, 500 Birch St., East Strouds burg. Pa..................................................................................................................... lj INTERNATIONAL EXPOSITION CO., 480 Lexington Ave., New York 17, N.Y. I?1 IRON LUNG VENTILATOR CO., 5407 Prospect Ave., Cleveland 3, Ohio........ If JACKSON & CHURCH CO., Saginaw, Mich.......................................................... ^ JENKINS BROS., 100 Park Ave., New York 17, N. Y............................................. 1 JOHNS-MANVILLE, 22 East 40th St., New York 16, N. Y.................... 1592-1 S. T. JOHNSON CO., 940 Arlington Ave., Oakland 8, Calif..........................1508-1. _ -NNARD CORP., 1819 S. Hanley Rd., St. Louis 17, Mo.................................... 1235 REWANEE-ROSS CORP., Kewanee, 111................................ 1479-1480-1481-1482-1483 KII.1.EBREW ENGINEERING CORP., 8640 Pardee Lane, St. Louis 23, Mo... 1518 ?ERLY-CLARK CORP., Neenah, Wis..'.................................................... 1594-1595 KNOWLES MUSHROOM VENTILATOR CO., Upper Montclair, N. J............. 1385 KRAISSL CO., INC., THE, 297 Williams Ave., Hackensack, N. J.................... 1530 KRITZER RADIANT COILS, INC., 2909A Lawrence Ave., Chicago 25, 111....... 1464 MSH CO., Cudahy, Wis........................................................................................... 1407 U BLOWER CO., THE, 2007 Home Ave., Dept. H, Dayton 7, Ohio......... 1338-1339 LEE CORP., 1011 Tatnall St., Wilmington, Del....................................................... 1225 LESLIE CO., 266 Grant Ave., Lyndhurst, N. J........................................................ 1425 LlLIE-HOFFMANN COOLING TOWERS, INC., 4239 Duncan Ave., St. Louis 'i'/? 10, Mo......................................................................................................................... 1295 LOCKPORT MILLS INC., (formerly Lockport Cotton Batting Co.), Lockport, ............................................................................................................................. 1596 ;M MAID-O'-MIST, INC., 3217 N. Pulaski Rd., Chicago 41, HI.......................... 1550-1551 CHARLES E. MANNING CO., 4135 Brownsville Rd., Pittsburgh 27, Pa........... 1280 MARLEY CO., THE, 222 W. Gregory, Kansas City 5, Mo....... ......................... 1296 MAKLO COIL CO., 6135 Manchester Ave., St. Louis 10, Mo.............................. 1314 JAS. P. MARSH CORP., Dept. 5, Skokie, HI.....................................................1552-1553 MAXITROL CO., 12200 Beech Rd., Detroit 28, Mich............................................. 1426 McCORD CORP., Air Conditioning & Refrigeration Div., Detroit 11, Mich... 1238 McDONNELL & MILLER, INC., 3500 N. Spaulding Ave., Chicago 18, M v...................................................................................... 1490-1491-1492-1493 MpQUAY, INC., 1602 Broadway, N.E., Minneapolis 13, Minn................... .1236-1237 MERCOID CORP., THE, 4201 Belmont Ave., Chicago 41, 111.............................. 1427 METALBESTOS DIV.,WILLIAMWALLACE CO., Belmont, Calif.................1498-1499 MILWAUKEE GAS SPECIALTY CO., 730 N. Jackson St., Milwaukee 2, Wis.. 1430 MINNEAPOLIS-HONEYWELL REGULATOR CO., 2644 Fourth Ave., So., ^^Minneapolis 8, Minn...........................................................................................1428-1429 JgRACLE ADHESIVES CORP., 214 East 53 St., New York 22, N. Y................. 1570 vJggINE MFG. CO., 1515 Dekoven Ave., Racine, Wis....................................1240-1241 MOELLER INSTRUMENT CO., 132nd St. and 89th Ave., Richmond Hill 18, "3 - N. Y................... 1431 MFG. WORKS, INC., 2509 E. Ontario St., Philadelphia 34,'Ea'.;! 1299 '"JOORE DRY KILN CO., 1220 W. State St., Jacksonville, Fla............................ 1306 MORRKon PRODUCTS, INC., East 168th St. and Waterloo Rd., Cleveland 10> Ohio.................................................................................................'.................. 1340 jM^-KLe MFG. CO., 666 Belford Road, Owatonna, Minn.................................... 1363 FURNACE CO., Milwaukee15, Wis........................................ 1200-1201 vMUNDET CORK CORP., Insulation Div., 7105 Tonnelle Ave., North Bergen, " J................................................................................................................ 1S97 J- Murray MFG. CO., Wausau, Wis....................................................... !.... 1239 N ASHENGINEERING CO.,THE, 234 Wilson Rd., South Norwalk, Conn.. .1528-1529 Sf'rfA?AL HEATER CO., 2180 Cleora Ave., St. Paul 4, Minn........................ 1226 WniA?!lAL RADIATOR CO., THE, Johnstown, Pa...............................1452-1453-1454 .OEKMAN NELSON DIVISION of the AMERICAN AIR FILTER CO., INC., Cm J,\?ESBITT. INC-. Philadelphia 36, Pa..................................................1244-1245 Tg* BLOWER CO., THE, 3145 S. Shields Ave., Chicago 16, HI........... 1341 im u ARA BLOWER CO., 405 Lexington Ave., New York 17, N. Y................... 1186 s V- NICHOLSON & CO., 211 Oregon St., Wilkes-Barre, Pa.................. 1554-1555 A,tv?^SS co-> Mansfield, Ohio.......................................................................... 1556 TM A. OLSON & CO., Broad and Court Sts., Canfield, Ohio................. 1227 OER & SEMBOWER, INC., Morgantown Rd., Reading, Pa............................. 14 OWENS-CORNING FEBERGLAS CORP., Toledo 1, Ohio.............................1281, l ' OWENS-ILLINOIS, General Offices, Toledo 1, Ohio.......................................... li PACIFIC LUMBER CO., THE, 100 Bnsh St., San Francisco 4, Calif................... 1- PACIFIC STEEL BOILER DIV., U. S. RADIATOR CORP., Detroit 31, Mich........................................................................................................................1456-145 SID E. PARKER BOILER MFG. CO., INC., 2035 East 37 St., Los Angeles % 58, Calif................................. :................................................................................... 1 PARKS-CRAMER CO., Fitchburg, Mass............................................................ 1188-1189 PATTERSON-KELLEY CO., INC., THE, 101 Burson St., East Stroudsburg, ' Pa.................................................................... ............................................................ r PEERLESS ELECTRIC CO., Fan and Blower Div., Warren, Ohio....................... 1 PEERLESS PUMP DIVISION, FOOD MACHINERY AND CHEMICAL CORP., 301 West Avenue26, Los Angeles 31, Calif......................................... 153 PENN CONTROLS, INC.,Goshen, Ind...................................................................... 143 PENN VENTILATOR CO., Goodman above Allegheny Ave., Philadelphia 40, Pa................................................................................................................................. 13/ PENNSYLVANIA FURNACE & IRON CO., 316 N. Pine St., Warren, Pa........... iff# PERFEX CORP., Milwaukee 7, Wis........................................................................... H PITTSBURGH CORNING CORP., One Gateway Center, Pittsburgh 22, Pa................ 1578-15 PITTSBURGH LECTRODRYER CORP., Foot of 32nd St., P. O. Box 1766, ' Pittsburgh 30, Pa...................................................................................................... 1187 PLUMBING AND HEATING JOURNAL (publication), 92 Martling Ave., Tarrytown, N. Y....................................................................................................... 1W: H. W. PORTER & CO., INC., 817-G Frelinghuysen Ave., Newark, 5, N. J...... 157 POWERS REGULATOR CO., THE, General Office and Factory, 3400 Oakton St., Skokie, 111...........................................................................................1434-1435-14$ J. F. PRITCHARD & CO., Dept. 320, 210 West 10th St., Kansas City 5, Mo. li PROPELLAIR DIVISION, ROBBINS & MYERS, INC., 1947 Clark Blvd., ?. Springfield, Ohio..................................................................... ............................... 1 PUR AIR DIV., BARNEBEY-CHENEY CO., Cassady & 8th Aves., Columbus 3, Ohio................................................................................................................... 1268-r PYLE-NATIONAL CO., THE, Multi-Vent Div., 1363-78 N. Kostner Ave., 4 Chicago 51, 111..................... 1386-1387-1388 R RAY OH BURNER CO., 1301 San Jose Ave., San Francisco 12, Calif........... 1510-151 C. L. RAYFEBLD CO., 2010-18 S. Halsted St., Chicago 8, HI.................................. 151 READY-POWER CO., THE, 11231 Freud Ave., Detroit 14, Mich....................... 131 REED UNIT-FANS, INC., 1001 St. Charles Ave., New Orleans, La................... 1/ REFLECTAL CORP., A SUB. OF BORG-WARNER CORP., 155 East 44th St., ? New York 17, N. Y................................................................................................... 1, REFRIGERATION ECONOMICS CO., INC., 1231 Tuscarawas St. E., Canton t 2, Ohio....................................................................................................................... 13 REFRIGERATION ENGINEERING, INC., 7250 E. Slauson Ave., Los Angeles -s 22, Calif......................:............................... :............................................................ *5 REGISTER & GRHLE MFG. CO., INC,, 70 Berry St., Brooklyn 11, N. Y....... 1,, RESEARCH PRODUCTS CORP., Madison 10, Wis............................................... If? REVCOR, Dept. R, Carpentersville, 111..................................................................... 1^ REVERE COPPER & BRASS, INC., 230 Park Ave., New York 17, N. Y............ I2?? RHEEM MFG. CO., 570 Lexington Ave., New York 22, N. Y........................ 1202-1203 RIC-WIL CO., THE, 24 Brown St., Barberton, Ohio............................. ............... 1?" RITE ENGINEERING & MFG. CORP., 144 S. Mission Rd., Los Angeles 33, J Calif............................................................................................................................. RITTLING CORP., THE, Rand Bldg., Buffalo 3, N. Y......................................... 1* ROCHESTER MFG. CO., INC., 80 Rockwood St., Rochester 10, N. Y............... 1# ROME-TURNEY RADIATOR CO., THE, Erie Blvd., East, Rome, N. Y........... 1? *?*...Advertisers 1139 -S Page [SSNTA FE TANK & TOWER CO., 5401 S; Boyle Ave., Los Angeles 11, Calif. 1298 ISARCOCO., INC., Empire State Bldg., New York 1, N. Y........................... 1558-1559 S5RCQTHERM CONTROLS, INC., Empire State Bldg., New York 1, N. Y... 1557 gsCHNACKE, INC., 1101 N. Governor St., Evansville, Ind.................................. 1317 BSERYEL AIR CONDITIONING DIVISION, Evansville, Ind.......................... 1204-1205 iSHAW-PERKINS MFG. CO., 201 E. Carson St., Pittsburgh 19, Pa................. 1465 Sheet METAL WORKER (publication), 92 Martling Ave., Tarrytown, N. Y... 1611 ISSh/SHELDON EQUIPMENT CO., Muskegon, Mich.................................. 1356-1357 (SHELDONS ENGINEERING LIMITED, Galt,Ontario, Canada........................ 1346 SHIMON MFG. CO., 1819 Holmes St., Kansas City 8, Mo.................................. 1500 gSHVERCOTE PRODUCTS, INC., 161 E. Erie St., Chicago 11, III.................... 1605 gjSIMPLEX MFG. CO., 198-206 N. Main St., Fond du Lac, Wis.......................... 1438 fSEHPMORE CORP., St. Joseph, Mich.................................................................... 1532 jBfBfe'SMITH CO., INC., THE, Westfield, Mass................................................... 1462 iSNiPS MAGAZINE (publication), 5707 W. Lake St., Chicago 44, HI.............. 1612 IH5, T.?S0MERS, INC., 6063 Wabash Ave., Detroit 8, Mich............................ 1282-1283 JSONNER-BURNER CO., THE, 412-420 East 6th Ave., Winfield, Kansas.... 1501 (SPENCE ENGINEERING CO., INC., 28 Grant St,, Walden, N. Y................... 1439 (SPENCER HEATER, LYCOMING DIVISION--AVCO MFG. CORP., Wil- TlSliamsport, Pa.................................................................. 1460-1461 SPRAYO-FLAKB INSULATION CO., 2727 Irving Park Road, Chicago 18, HI... 1586 (STANDARD ELECTRIC MFG. CO., West Berlin 69, N. J................. 1347 (STANDARD STAMPING & PERFORATING CO., 3111 West 49th Place, pll.Chlcago 32, HI........................................................................................................... SHEETING, INC., 3738 N. Holton St., Milwaukee 12, Wis................................. (STEWART MFG. CO., INC., Cedar Grove, Essex County, N. J........................ 1390 1440 1391 (STRONG, CARLISLE & HAMMOND CO., 1392 W. Third St., Cleveland 13, B#OUo........................................................ J560 pURFACE COMBUSTION CORP., 2375 Dorr St-','Toledo 1, Ohio. .!.... 1206-1207 (SWARTWOUT CO., THE, 18511 Euclid Ave., Cleveland 12, Ohio..................... 1365 (SYNCROMATIC CORP., 1141 Tenth St., Watertown, Wis.................................. 1211 JFSL T |TACO HEATERS, INC., 137 South St., Providence 3, R. 1.......................... i4S,OR FORGE * PIPE WORKS, INC., P. O. Box 485, Chicago 90, 111.... BAILOR INSTRUMENT COMPANIES, Rochester 1, N. Y................................ |THERMOBLOC DIV., PRAT-DANIEL CORP., Meadow St., South Norwalk, pi/Conn................................................................... 1519 1408 1441 j22g * CO.. Peru, Ind........................................................................ 1520-1521 CORP-> 113 East 8th St., Waterloo, Iowa................................. 1392-1393 ffioN WORKS CO., THE, DIV. OF STRUTHERS WELLS ^T,n^^ltUSViUe- Pa........................................................................................ 1484-1485 MFG' co- the- 50 FrankUn St., Torrington, Conn......... 1348-1349 lTR4wn'^Nr> MOTORFANS, INC., 5725 So. Main St., Los Angeles 37, Calif. 1350 iwrivW THE. 2021 Cameron Ave., LaCrosse, Wis..................................1246-1247 ElgTraKs,1m000cIs(LlaonudlsAvvilele., M1cKKye.e..s...R...o...c..k.s;,...P..a........................................................................................... 11420895 KETTLE & BAHEY, INC., New Britain, Conn................................................. 1394-1395 jp/ |S u WED STATES AIR CONDITIONING CORP., 3321 Como Avenue, S.E., f% Mtaneapolls 14, Minn........................................................................................... . .1190 lim^i.ECTRICA1, MOTORS, INC., Box 2058, Los Angeles 54, Calif............... 1354 I^HTTED STATES GYPSUM CO., 300 W. Adams St., Chicago 6, 111................... 1599 IfiNrroS stATES RADIATOR CORP., Detroit 31, Mich.............................. 1458-1459 fyUTED STATES REGISTER CO., Battle Creek, Mich................................1396-1397 |S2TMSTATES STEEL, Pittsburgh, Pa.................... 1367 |nTn T"RSAL DIFFUSER CORP., 1360 Garrison Ave., New York 59, N. Y.... 1398 iUTTT itv APPLIANCE CORP., 4851 S. Alameda St., Los Angeles 58, Calif.. 1208-1209 FAN CORP., A DIV. OF UTILITY APPLIANCE CORP., 911 East * t., Los Angeles 1, Calif................................................................................... 1210 II1- gsSb V VAPOR HEATING CORP., 80 E. Jackson Blvd., Chicago 4, 111......................... 31 VIKING AIR CONDITIONING CORP., DIV. of THE NATIONAL RADIATOR CO., 5601 Walworth Ave., Cleveland 2, Ohio.................................................... '4 VORTOX CO., Claremont, Calif.................................... .......................................... VULCAN RADIATOR CO., THE, 26 Francis Ave., Hartford 6, Conn............... i W WAGNER ELECTRIC CORP., 6464 Plymouth Ave., St. Louis 14, Mo..............ri WATERLOO REGISTER CO., INC., P. O. Box 72, Waterloo, Iowa................. 13 WATERMAN-WATERBURY CO., THE, 1121 Jackson St., N. E., Minneapolis 13, Minn................................................................................................................1212-- WARREN WEBSTER & CO., 1731 Federal St., Camden 5, N. J........ 1562-1563-r WEBSTER ENGINEERING CO., THE, DIV. of SURFACE COMBUSTION CORP., 115 S. Frisco St., P. O. Box 2168, Tulsa, Okla.............. .............. 1, WEIL-McLAIN CO., General Sales Office, Michigan City, Ind........................... T WESIX ELECTRIC HEATER CO., 390 First St., San Francisco 5, Calif......... 12 WESTERN BLOWER CO., 1800 Airport Way, Seattle 4, Wash.......................... 135 WESTERN ENGINEERING & MFG. CO., 4112 Ocean Park Ave., Venice, Calif............................................................................................................................. 1 WESTINGHOUSE ELECTRIC CORP., Air Conditioning Div., Hyde Park, Boston 36, Mass....................................................................................................... U WESTINGHOUSE ELECTRIC CORP., STURTEVANT DIV., Hyde Park, Boston 36, Mass...............................................................................................1287, 1^ C. H. WHEELER MFG. CO., 19th & Lehigh, Philadelphia 32, Pa.................. 153 WHITE-RODGERS ELECTRIC CO., 1209 Cass Ave., St. Louis 6, Mo........... I EDWIN L. WIEGAND CO., 7672 Thomas Blvd., Pittsburgh 8, Pa.................... 1 WILL-BURT CO., THE, Orrville, Ohio.................................................................... 1 WILSON & CO., INC., Air Filter Div., 4100 S. Ashland Ave., Chicago 9, 111... 1 L. J. WING MFG. CO., 59 Vreeland Mills Road, Linden, N. J...........1249 1250-125 WOLVERINE TUBE DIVISION of CALUMET & HECLA, INC., 1417 Central Ave., Detroit 9, Mich.............................................................................................. ! WOOD CONVERSION CO., Dept. 220-4, First National Bank Bldg., St. Paul 1, Minn....................................................................................................................... WORTHINGTON CORP., Air Conditioning & Refrigeration Div., Harrison, i N. J........................................................................................ ..................................... Y YARNALL-WARING CO., 133 Mermaid Ave., Philadelphia 18, Pa.................... YORK CORP., York, Pa........................................................................................ YORK-SHIPLEY, INC., York 16, Pa....................................................................... YOUNG RADIATOR CO., Dept. 544, Racine, Wis................................................. YOUNG REGULATOR CO., 5209 Euclid Ave., Cleveland 3, Ohio..................... 1, 11 1 125 1 Z Z-CRETE DIVISION, ZONOLITE CO., 135 S. LaSalle St., Chicago 3, 111----- 151 JOHN ZINK CO., 4401 S. Peoria,Tulsa,Okla......................................................1502-1 i iULATORS ,tr'- Specialty Mfg. Corp., 1185 ;1M7. Kennard Corp., 1235 ijyInc., 1236-1237 Mario Coil Co., 1314 ' Corp., 1192 McCord Corp., 1238 McQuay, Inc., 1236-1237 Modine Mfg. Co., 1240-1241 ^Ad_h_e_s_i_v_e_s__C__or,p., 1570. John J. Nesbitt, Inc., 1244-1245 Niagara Blower Co.. 1188 ___ _ __ w., Tire A Rubber Co., 1279 Patterson-Kelley Co., Inc., The, Curtis Refrigerating Div of Curtis Mfg. Co., 1312 * Refrigeration Economics Co., Inc., Prayer-Hanson, Inc., 1181 RBERS, Odor 1248 Farr Co., 1276-1277 ihey-Cheney Co., 1268-1269 RefrigerationEngineering, Inc., Fedders-Quigan Com.. 1231 ''-Engineering Corp., 1272- 1316 Frick Co., 1313 Rome-Turney Radiator Co., The, Frigidaire, Div. of General Motors 1309 . 1184 * Trane Co., The, 1246-1247 General Electric Co., 1182-1183 SORPTION SYSTEMS United States Air Conditioning Hastings Air Conditioning Co Inc 1 'ey-Cheney Co., 1268-1269 Corp.. 1190 " ftpr.'''Engineering Corp., 1272- WestinAouse Electric Corp., Air Hunter Fan & Ventilating Co.. Inc sura; Conditioning Div.; 1191 1334 |Co;f^"A12i6r 8--D12--i6v9., Barn--ebe--y--Cvheney Worthington C~orp., 1192 York Corp., 1193 S. T. Johnson Co., 1508-1509 Kennard Corp., 1235 Young Radiator Co., 1252 Mario Coil Co., 1314 ^CLEANING EQUIPMENT Jfce also Filters, Air) TM,..|^.`Rfrigeration Corp., 1171 Wir Devioes, Inc., 1261 "^Filter Com., 1264 xvMase C'"orfpm,, The, 1262-1263 AIR CONDITIONING COMPRESSION EQUIPMENT Airtemp Div., Chrysler Corp., 1196- 1197 nBrruunnner aMufg. cCoo.., I1a31n1 McQuay, Inc., 1236-1237 L. J. Mueller Furnace Co., 1200-1201 John J. Nesbitt, Inc.. 1244-1245 Niagara BlowerCo.,fl86 Parks-Cramer Co., 1188-1189 Pattereon-Kelley Co., Inc., The, 1307 Air Filter Co., Inc., 1285- Carrier Corp., 1178-1179 Ready Power Co., The, 1315 ncan Moistening Co., 1174 ncan Radiator A Standard JC^adjXitainrreto^CrDollriiovv.-,., 1nS1i(u1f-4n_Ubfel3Aa5rm Air The' 1534-1535 n Co., The, 1176-1177 ' ney Co., 1268-1269 nic Engineering Co., Curtis Refrigerating Machine Div. of Curtis Mfg. Co., 1312 Frick Co., 1313 Fri1itg1m8id4aire Div. of General Motors, ' General Electric Co., 1182-1183 Ready Power Co., The, 1315 Schnacke, Inc., 1317 Servel, Inc., 1204-1205 Refrigeration Economic Co., Ino. 1248 Refrigeration Engineering JnC 1316 Schnacke, Inc., 1317 Servel, Inc., 1204-1205 Sheldons Engineering Ltd., 1346 Surface Combustion Corp., 1206 1207 ,_ j .. iSrUL1*TMkent ISC 1271 a Corp.. (formerly Staynew 1274"1275 m6'1277 IGlaafloea, 1278 ISSfxilTar Tire 4 Rubber Co.. 1279 115. Manning Co., 1280 Kl28r`l5(5i* FiberBl" Corp., Txiraaunue uCuo..,, T1UhCe,, w12i4u6--i1o24*/7 Westinghouse Electric Corp., Air CConodnidtiiotinoinnigngDDiviv.,11101191 Worthington Corp., 1192 York Corp., 1193 __________ AIR CONDITIONING CON- TROLS (See Controllers and Control Equipment, Humidity and TArraanuev UCol..,. T1Bhe8,, 1246-1247 United States Air Conditioning CCoorrnp., l1i1o9n0 ^ Waterman-Waterbury Co., The. 1212-1213 ' Western Blower Co., 1352 Westinghouse Electric Corp., Air Conditioning Div., 1191 Worthington Corp*. 1192 York Corp., 1193 Temperature Controls) wiS-1357 don EqmPmeat Co-. Yoouu:ng Radiator Co., 1252 Jo>l hn Zink Co., 1502-1503 Somers, Inc., 1282-1283 _ a, Inc., 1285 igatax Co., 1286 Co^-. Stur- AIR CONDITIONING REGIS TERS AND GRILLS (See Grilles, Registers) AIR COOLING EQUIPMENT (See Cooling Equipment, Air) BK?011 * Co., Inc., 1288 pte-' (See Com- fesSOe.N?300COILS in Div '... '* Chrysler Corp., 1196- K^Mncan BWt pTM fljell A Yffi,,,rffl2~l273 [Gwrier 1517 ^yer-Hansin Tm. ,101 ^<3rP., 1304 AIR CONDITIONING SCREEN AIR COOLING. HUMIDIFY- (See Shade Screening) ING AND DEHUMIDIFYING APPARATUS _________ Aerofin Corp., 1301-1303 AIR CONDITIONING UNITS Air A Refrigeration Corp., 1171 AAcommeh IInnHduiiesttvriienos, IInnnc., l1i3n0n0 AA irtemp TD?i:v..., VCvhi__r_y_s_ler Corp., Air A Refrigeration Corp., 1171 1196-1197 Airtemp Div., Chrysler Corp., 1196- American Blower Corp.. 1272-1273 1197 American Moistening Co., 1174 American Blower Corp., 1272-1273 American _F_u_r_n_a_c_e__C_o_.,, 1216 American Radiator A Standard Sanitary Corp., Sunbeam Air American Moistening Co., 1174 Conditioner Div., 1194-1195 American Radiator A Standard Armstrong Muhina Works, 1536- Sanitary Corp., Sunbeam Air 1537 Conditioner Div., 1194-1195 Bahnson Co., The, 1176-1177 Bell A Gossett Co., 1516-1517 Bahnson Co., The, 1176-1177 Bayley Blower Co., 1321 Brookside Products Co., Inc., 1323 tfi. Please mention THE GUIDE 1954 when writing to Advertisers 1141 Brown Products Co., 1446 AIR FILTER GAGE Buensod-Staoey, Inc., 1175 Air Devices, Inc., 1261 Buffalo Forge Co., 1325 Owens-Coming Fiberglas Corp., Carrier Corp., 1178-1179 1281. 1585 Clarage Fan Co., 1180, 1329 Research Products Corp., 1284 Drayer-Hanson, Inc., 1181 Farr Co., 1276-1277 Frick Co., 1313 AIR FILTERS (See Filters, Air; General Electric Co., 1182-1183 Air Cleaning Equipment) Kennard Corp., 1235 Mario Coil Co., 1314 HcQuay, Inc., 1236-1237 AIR MEASURING INDICAT Modine Mfg. Co., 1240-1241 ING AND RECORDING IN D. J. Murray Mfg. Co., 1239 John J. Nesbitt, Inc., 1244--1245 STRUMENTS Anemoetat Corp. of America, 1374 Niagara Blower Co., 1186 1375 Parka-Cramer Co., 1188-1189 Illinois Testing Laboratories, Inc., J. F. Pritchard A Co., 1297 1424 Ready Power Co., The, 1315 Minneapolis-Honeywell Regulator Refrigeration Economics Co., Inc., Co., 1428-1429 1248 Parks-Cramer Co., 1188-1189 Refrigeration Engineering Inc., 1316 Taylor Instrument Co's., 1441 ' Serve!, Inc., 1204-1205 Tnon, Inc., 1285 Sheldons Engineering Ltd., 1346 Surface Combustion Corp., 1206 1207 Trade-Wind Motorfans, Inc., 1350 AIR MOISTENING APPARA TUS (See Humidifier*) Trane Co., The, 1246-1247 United - States Air Conditioning Corp., 1190 AIR PURIFYING APPARATUS Utility Appliance Corp., 1208-1209 Air A Refrigeration Corp., 1171 Westinghouse Electric Corp., Air Air Filter Corp., 1264 Conditioning Div., 1191 V. D. Anderson Co., The, 1534-1535 Worthington Corp., 1192 Bamebey-Cbeney Co., 1268-1269 York Corp., 1193 Young Radiator Co., 1252 Connor Engineering Corp., 1272 1273, 1378-1379 Dollinger Corp., 1274-1275 Charles E. Manning Co., 1280 AIR DIFFUSER UNITS, Hlfch Pressure . Anemoetat Corp. of America, 1374-- 1375 Tuttle A Bailey, Inc., 1394-1395 J. F. Pritchard A Co., (Puridryer Dept.), 1297 H. J. Somers. Inc., 1282-1283 Trion, Inc., 1285 Universal Diffuser Corp., 1398 Wilson A Co., Inc., 1288 AIR DIFFUSERS AND VENTI AIR RECEIVERS (See Receiver*, LATORS. CEILING. FLOOR Air) AND WALL Air Control Products, Inc., 1368-1371 Air Devices, Inc., 1261 AIR RECOVERY, Method of Aladdin Heating Corp., 1318 Bamebey-Cheney Co., 1268-1269 Anemcetat Corp. of America, 1374-- Connor Engineering Corp., 1272 1375 . 1273, 1378-1379 Auer Register Co., The, 1373 Barber-Colman Co., 1376, 1411 Connor Engineering Corp., 1272 AIR TRAPS (See Trap*, Air) 1273, 1378-1379 Charles Demuth A Sons, Inc., 1377 Hart A Cooley Mfg. Co., 1380-1381 Hendrick Mfg. Co., 1382-1383 Independent Register Co., The, AIR TUBING, Flexible Metal (See Tubing, Flexible Metallic) ATOMIZING SPRAY NOl-- (See Spray Nozzles) % jv 1384 ,, Knowles Mushroom Ventilator Co., 1365 Minneapolis-Honeywell Regulator AIR TURNING VANES Vanes, Air Turning) ATTIC FAN COOLERS^ (See. Fans, Attic; Ventilator*, " Co., 1428-1429 Pyle-National Co., The, Multi-Vent AUTOMATIC FUEL BURNJJ Div., 1386-1388 AIR VELOCITY METERS (See EQUIPMENT (See Burners^ Register & Grille Mfg. Co., Inc., Meter*) tomatic: Gas Burners; OH Bi 1389 Stokers) Standard Stamping A Perforating Co., 1390 Titus Mfg. Corp., 1392-1393 Tuttle A Bailey, Inc., 1394-1395 United States Register Co., 1396-- 1397 Universal Diffuser Corp., 1398 Waterloo Register Co., 1399 AIR WASHERS Air A Refrigeration Corp., 1171 American Blower Corp., 1272-1273 Babnson Co., The, 1176-1177 Bayley Blower Co., 1321 Bishop A Babcock Mfg. Co., The, (Massachusetts Blower Div.), 1322 Buensod-Stacey, Inc., 1175 AUTOMATIC SHUTTERS?' Shutter,, Automatic) AXIAL FLOW FANS (S ?. Axial Flaw) . AIR DUCTS CSee Duet*) Buffalo Forge Co., 1325 Carrier Corp., 1178-1179 Clarage Fan Co., 1180, 1329 Continental Air Filters, Inc., 1271 BASEBOARD HEATING Air Control Products, Inc., American Radiator A Stan AIR ELIMINATORS V. D. Anderson Co., The, 1534-1535 C. A. Dunham Co., 1541-1543 Illinois Engineering Co., 1548-1549 Maid-O'-Mist, Inc., 1550-1551 Jaa. P. Marsh Corp., 1552-1553 Dollinger Corp., 1274-1275 Mario Coil Co., 1314 D. J. Murray Mfg. Co., 1239 Niagara Blower Co., 1186 Parks-Cramer Co., 1188-1189 Sheldons Engineering Ltd., 1346 Trane Co.. The, 1246-1247 Sanitary Corp., 1444-1445 Brown Products Co., 1446 Burnham Corp., 1450 _ Campbell Heating Co., 1218-121? Crane Co., 1448-1449 ,, '-h C. A. Dunham Co., 1541-1543,^ Edwards Engineering Corp.! Sarco Co., Inc., 1558-1559 Western Blower Co., 1352 Feddera-Quigan Corp., 1231 Numerals followlno Manufacturers* Names refer to pages in the Catalog Data Section -- ** GeneSaTAntoxnatic Products Corp., 145:--'. AffmanT'Specialty Mfg. Corp., 1644^1547 - ~ r-Radiant Coils, Inc., 1464 Herman Nelson Div., American Air Filter Co., Inc., 1242-1243 New York Blower Co., The, 1341 Sheldons Engineering Ltd., 1346 Utility Fan Corp., A Div. of Utility BLOWERS, Turbine General Blower Co., 1332 Western Blower Co., 1352 L. J. Wing Mfg. Co., 1249-1251 "SmeiDry. 4Ciln Co., 1306 Appliance Corp., 1210 'atihnal' Radiator Co., The, 1252- John#; '-NNesbitt, Inc., 1v2u44-1245 Rittiihg Corp., The, 1308 RBite Engineering A^MMfg. Corvp..,,^45*5, .omeVIumey Radiator Co., The, 1309 V ~ is Co.vThe, 1246-1247 iittle>'A Bailey, Inc., 1394-1395 United States Radiator Corp., 1458-1459 arreb Webster A Co., 1562-1564 Weil-McLain Co., 1463 Westinghouse Electric .Corp., Stur- tevant Div., 1353 ' L. J. Wing Mfg. Co., 1249-1251 BLOWERS, Heating and Venti lating Aladdin Heating Corp., 1318 American Blower Corp., 1272-1273 American Foundry A Furnace Co . 1214-1215 American A Standard Sanitary Corp., Sunbeam Air BLOWERS, Warm Air Furnace Aladdin Heating Corp., 1318 American Blower Carp., 1272-1273 American Foundry A Furnace Co 1214-1215 American Radiator A Standard Sanitary Corp., Sunbeam Air Conditioner Div., 1194-1195 Bishop A Babcock Mfg. Co*. The, (Massachusetts Blower Div.), 1322 Brundage Co., The, 1324 Campbell Heating Co., 1218-1219 Clarage Fan Co., 1180,1329 Conditioner Div., 1194-1195 General Blower Co., 1332 BELLOWS jexonics Corp., (Formerly Chicago Automatic Gas Equipment Co., 1230 Bayley Blower Co., 1321 Bishop A Babcock Mfg. Co.. The, Lau Blower Co., The, 1338-1339 Morrison Products, Inc., 1340 L. J. Mueller Furnace Co., 1^)0-1201 .Metal Hoee Corp.), 1258 (Massachusetts Blower Div.), 1322 Peerless Electric Co., The, 1342 IJulton'Sylphon Div., The, Robert- Brookside Products Co., Inc., 1323 ahaw-Fulton Controls Co.. 1416-- Brundage Co., The, 1324 1417. Buffalo Forge Co., 1325 Utility Applianoe Corp., 1208-1209 VilringAir Conditioning Corp., 1351 L. J. Wing Mfg. Co., 1249-1251 Campbell Heating Co., 1218-1219 E. K. Campbell Co., 1217 ENDS, Pipe, Ferrous and NonFerrous Grinhell Co., Inc., 1232-1233 Arthur Harris A Co., 1406 Parks-Cramer Co., 1188-1189 BENDS (See Pipe, Returns) Century Fan A Ventilator Co., 1326 Champion Blower A Forge Co., 1327 Chicago Blower Corp., 1328 Clarage Fan Co., 1180, 1329 C. A. Dunham Co., 1541-1543 Garden City Fan Co., 1331 General Blower Co.. 1332 Harteell Propeller Fan Co., Div. of Castle Hills Corpv 1333 Hastings Air Conditioning Co., Inc., BOILER-BURNER Air Devices, Inc., 1261, 1372 Airtemp Div., Chrysler Corp., 1196- Aldrich Co., 1443 American Radiator A Standard Sanitary Corp., 1444-1445 Brown Products Co., 1446 Bryan Steam Carp., 1447 Burnham Corp., 1450 KNOCKS, Asbestos Carey Mfg. Co., The, 1580 :1581 BLOCKS, Glass OTreM-IUmoa Glass Co., 1577 4*Tsburgh Coming Corp., 1578 "! ffijOTOR HOUSINGS Atlas Mfg. Co., 1538 _nmdage Co., The, 1324 Lnampion Blower A Forge Co., 1327 F" Co., U80, 1329 ' Jgofilower Co^The, 1338-1339 Wffitaghooae Electric Corp., Stur- aerant Die., 1353 ' ft*?; Ilg Electric Ventilating Co., 1234, 1335 Joy Mfg. Co., 1336-1337 Lau Blower Co., The, 1338-1339 McQu&y, Inc.. 1236-1237 Morrison Products, Inc., 1340 L. J. Mueller Furnace Co., 1200-1201 Herman Nelson Div., American Air Filter Co., Inc., 1242-1243 New York Blower Co., The, 1341 Niagara Blower Co., 1186 Peerless Electric Co., The, 1342 Refrigeration Engineering, Inc., 1316 Revoor, 1345 Sheldons Engineering Ltd., 1346 Standard Electric Mfg. Co., 1347 Torrington Mfg. Co., The, 1348-1349 Trane Co., The, 1246-1247 Utility Appliance Corp., 1208-1209 Viking Air Conditioning Corp., 1351 Western Blower Co., 1352 Cleaver-Brooks Co., 1467, 1495 Fitzgibbons Boiler Co., Inc.. 1474-- 1475 General Automatic Products Corp., 1451 General Electric Co., 1182-1183 Gordon A Piatt, 1497 Kewanee-Ross Corp., 1479-1483 L. J. Mueller Furnace Co., 1200-1201 National Radiator Co., The, 1452- Ray Oil Burner Co., 1510-1511 Rite Engineering A Mfg. Corp., 1455 H. B. Smith Co., Inc., The, 1462 Sonner Burner Co., The, 1501 Titusville Iron Works Co., The, (Div. of StrutherB-Wells Corp.), 1484-1485 United States Radiator Corp., 1458 1459 Weil-McLain Co., 1463 MOTORS <& Motor., Westinghouse Electric Corp., Sturtevant Div., 1353 L. J. Wing Mfg. Co., 1249-1251 BOILER COMPOUNDS Compounds, Boiler) (See ^g^RS- Centrifugal (See BLOWERS, Pressure American Blower Corp., 1272-1273 Bayley Blower Co., 1321 BOILER COVERING (See Cover ing, Pipe and Surfaces) Brookude Products Co., Inc., 1323 I*'*.'. (S" Pan*- Buffalo Forge Co., 1325 BOILER FEED PUMPS (See Century Fan A Ventilator Co., 1326 Pump*, Boiler Feed) Champion Blower A Forge Co., 1327 Chicago Blower Carp., 1328 Clarage Fan Co., 1180, 1329 Genera] Blower Co., 1332 BOILER FEEDERS (See Feeder*. Boiler Water) Hartzell Propeller Fan Co., Div. of Castle Hills Carp., 1333 Ilg Electric Ventilating Co., 1234, 1335 ' BOILER GRATES (See Orate* or Boilers) Ingersoll-Rand, 1527 Lau Blower Co., The, 1338-1339 Peerless Electric Co., The, 1342 Sheldons Engineering Ltd., 1346 Standard Electric Mfg. Co., 1347 BOILER JACKETS Atlas Mfg. Co., 1538 T --1?l^eCtric Ventilating Co., 1234- . feBfe^pu,1336-1337 ^Blower Co., The. 11338-1339 Westinghouse Electric Corp., Sturtevant Div., 1353 L. J. Wing Mfg. Co., 1249-1251 BLOWERS. Soot Economy Flue Cleaner Co., 1494 BOILERS. Cast-Iron Airtemp Div., Chrysler Corp., 1196 1197 American Radiator A Standard Sanitary Corp., 1444-1445 Burnham Corp., 1450 Please mention THE GUIDE 1954 when writing to Adrertlsers 1144 p- 144R-1448 Burnham Corp.. 1450 BOILERS, Steel General Electric Co., 1182-1183 Cleaver-Brooks Co., 14Q7 1195 Div- Chrysler Corp.,] L J. Mueller Furoaoe Co., 1200-1201 Combustion Engineering, Inc., 1468- 1197 Notional Radiator Co., The, 1462- 1469 MM ' Crane Co-1448-1449 Aldrich Co , 1443 ,, Brown Products Co., 1446 H B. Smith, Co- Inc- The, 1462 Cyclotherm Corp., Div- U. S. Bryan Steam Carp. 1447 S&rSp.^M "T- De^sM^.Co-MTl' &BrSS|i4.fi467, 1495| Surface Combustion Corp- 1206- 1io2r0y7r" " " United States Radiator Corp., s1e4e5o8-144i5M9 Weil-McLain Co., 1463 BOILERS, Down Draft Cleaver-Brooks Co., 1467, 1495 Farrar A Trefts, Inc., 1473 Johnson Bros., Inc., 147 7 Kewanee-Ross Coro-14764483 Titusville Iron Works Co- The Dutton Boilers, Division HapmanDDuuttttoonn CCoo..., 11447722 Ff arraarr Aa Txriceifwts,, Iiunc..,, 1473 TFGit'zrf-gyirbriHbKonnnsfl BHo/lileprf CCfot..., IInl c., 1474 1475 ^ _ General Electric Co., 1182-1183 International Boiler Works Co., The, 1476 S. T. Johnson Co., 1508-1509 Johnston Bros., Inc., 1477 Kewanee-Ross Corp., 1479-1483 L. J. Mueller Furnace Co- 1200-1201 National Radiator Co- The, 1452- ' Combustion Engineering, T 1468-1469 _ _ _ _ 'f Cyclotherm Div., U.S. Radis Corp., 1470 . Dewey-Shepard Boiler Co., 14 Dutton Boilers, Division Hap- Dutton Co.. 1472 `' Farrar & Treits, Inc., 1473 : * Fitzgibbons Boiler Co., Inc.,!147 1475 r-"' GFrnooe_ssn_ite_ee_rraWllmEhuelseeciletrriciC^owCfrtpo..-, 1u2w93 t, 1182-1183 International Boiler Works Co.,^ 1476 * (Div. of Struthera-Wells Corp.), ^ & gembower, Inc., 147s S. T. Johnson Co- 1508-1509 \ 1484-1485 Sid E. Parker Boiler Mfg. Co., 1486 Johnston Bros., Inc., 1477 Pennsylvania Furnace A Iron Co., Kewanee-Ross Corp., 1479-1483:? Ugg National Radiator Co., The, 1 BOILERS, Fire Tube Rite Engineering & Mfig. GCorp., i1s4o5o5 1454 ' Cleaver-Brooks Co., 1467. 1495 jtjt 3T> Smith Ci-or.., ITn--c---.',PTI,,h. e1,A1R4962 Orr A Sembower, Inc., 1478 Combustion Engineering, Inc., 1468- grUncer Heater, Lycoming Div., Sid E. Parker Boiler Mfg. Co.j l 1469 ,, . Orr A Sembower, Inc., 1478 ^ Avco MMffgg.TCCoorprp.,.^1460C-k1l4461 ' RRhheeeemm MMffgg.. CCoo..,, 11220022--11220033 ^* Surface Combustion Corp., 1206- Rite Engineering & Mfg. Corp.^1 1207 Spencer Heater, Lycoming ui Titusville Iron Works Co., The, Avoo Mfg. Corp., 1460-1461 BOILERS, Gas Fired Airtemp Div., Chrysler Corp., 1196-- 1197 Aldrich Co., 1443 American Radiator A Standard (Div. of Struthera-Wells Corp.), 1484-14S5 U__n_i_te__d__S_tates Radiator Corp., 1458-- 1459 Vapor Tfoaling Corp., 1487 Titusville Iron Works Co., (Div. of Struthera-Wells Corp? 1iv48m4-1i4w85 York-Shipley, Inc., 1513 Sanitary Corp., 1444-1445 Weil-McLain Co., 1463 Brown Products Co., 1446 York-Shipley, Inc., 1513 BOILERS, Unit Steam Gen Bryan Steam Corp., 1447 ator /' Burnham Corp., 1450 Cleaver-Brooks Co., 1467, 1495 BOILERS, Magazine Feed Cleaver-Brooks Co.? 1467, 1495-\ Combustion Engineering, .1 ' Combustion Engineering, Inc., 1468- Farrar & Trefts, Inc., 1473 11446688-1-1446699 X 1169 _ ... Spencer Heater, Lycoming Div., Cyclotherm Div.. U. S. Radia Crane Co., 1448-1449 *Avco Mfg. Corpn.,. 1460-1446611 Corp., 1470 '.%> Cyclotherm Div., U. S. Radiator Duttoa'Boilera, Division Haps Corp., 1470 , Dewey-Shepard Boiler Co., 1471 BOILERS, Oil Burning Dutton Co., 1472 ^ International Boiler Works Co.,'. Dutton Boilers, Division Hapman- ^Air Devices, Iinc., 1iz2o61i, 11337/22 1479 Dutton Co.. 1472 Airrtt^eTmTmp Div.., Chrvyasler Corop., 1196- Johnston Bros., Inc., 1477 .. Farrar A Treits, Inc., 1473 1197 Kewanee-Ross Corp., 1479-14835? Aldrich Co., 1443 Orr & Sembower, Inc., 1478 r American Radiator A Standard Titusville Iron Works Co., -T-. Fitzgibbons Boiler Co., Inc., 1474- Sanitary Corp., 1444-1445 1475 Babcock A Wilcox Co., The, 1466 General Electric Co., 1182-1183 Brown Products Co., 1446 International Boiler Works Co., The, Bryan Steam Corp., 1447 1476 Burnham Corp., 1450 Johnston Bros., Inc., 1477 Cleaver-Brooks Co.r 1467, 1495 Kewanee-Ross Corp., 1479-1483 Combustion Engineering, Inc., (Div. of Struthera-Wells Cofo >1..4..8..4..-.1..4..8.5. v* United States Radiator Corp.,.l 1459 Vapor Heating Corp., 1487 $ York-Shipley, Inc., 1513 L. J. Mueller Furnace Co., 1200-1201 1468-1469 Nal1l4tti5o4inal Radiator Co., The, 1452- J"C_r_anUejkCnwo.M, 14n48it-f1449TT s- " ssmzas?0? Sid E. Parker Boiler Mfg. Co., 1486 Pennsylvania Furnace A Iron Co., ESteSSBS-aS* 1199 . _ Rite Engineering A Mfg. Corp., Dutton Co.. 1472 i 1455 H. B. Smith Co.. Inc., The, 1462 Spencer Heater, Lycoming Div., AAvvccoo MMffgg.. CGoorrpp..,, 1144W60--1i46u1 Surface Combustion Corp., 1206- 1207 , Titusville Iron Works Co., The, (Div. of Struthera-Wells Corp.), 1484-1485 United States Radiator Corp., 1458- Va1p45o9r Heating Corp., 1487 M74- General Electric gCoo..., u11b82--1ii1m83 International Boiler Works Co., The, 1476 S. T. Johnson Co., 1508-1509 Johnston Bros., Ino., 1477 Kewanee-Ross Corp.. 1479-1483 National Radiator Co., The, 1452 Or1r46A4 Sembower, TInc., 1478 isoa-isoy :? PtfnriLCo..* International Boiler ^ 1476 ,^ % Rite Engineering A Mfg. Corpus H. B. Smith Co., Inc., Tbe,?l Titusville Iron Works (Div. of Struthera-Wells 1484-1485 Weil-McLain Co., 1463 Sid E. Parker Boiler Mfg. Co., 1486 H. B. Smith Co., Inc., The, 1462 BRACKETS, Radiator , Spencer Heater, Lycoming Div., American Radiator A Stan BOILERS, Heating Avco Mfg. Corp., 1460-1461 Sanitary Corp., 1444-1445 >. Airtemp Div., Chrysler Corp., 1196- Titusville Iron Works Co., i he, Carty & Moore Engineering] 1197 (Div. of Struthera-Wells Corp.), 1&4q Babcock A Wilcox Co., The, 1466 Brown Products Co., 1446 Bryan Steam Corp* I447 Vaopor Heating Corp., 1487 Weil-McLain Co., 1463 York-Shipley, Inc., 1513 Un14it5e4d States Radiator 1458-1459 ' -V Numerals following Manufacturers' Names refer to pages In the Catalog Data Section g 1145 PROTECTION, Gas CEMENT, Insulating UHiion.CoiitTwl Corp., 1133 id Corp., The, 1427 SGontrols, Inc., 1432 Philip Carey Mfg. Co., The, 1580 COILS, Ammonia 1581 Acme Industries, Inc., 13GO Johna-Manville, 1592-1593 Aerofm Corp., 1301-1303 Owens-Coming Fiberglas Corp., Drayer-Hanson, Inc., 1181 1281, 1585 Mario Coil Co., 1314 BURNERS, Automatic ggHeKGd:1443 ^ Krtohiatic Burner Corp., 1506 Sver-Brooks Co., 1467, 1495 a'Co:; 1495 . .xrpnse' Engine A Machinery .5&?Brirher Div., Sub. of General IjjbSfe&Ccirp., 1507 rdra'A-Piatt, 1497 ^Johnson Co., 1508-1509 Burner Co., 1510-1511 BSE.Rayfield Co., 1512 SonnorBurner Co.. The, 1501 United'States Radiator Corp., 1458- *1459^; FTebeter,Engineering Co., The, 1509 .York-Shipley, Inc., 1513 (johh'Zink Co., 1502-1503 Z-Crete Div., Zonolite Co., 1576 CEMENT. Mineral Wool Philip Carey Mfg. Co., The, 1580 1581 CEMENT, Refractory GSee Re fractories) CHIMNEY TOPS G. C. Breidert Co., The, 1359 Penn Ventilator Co., 1364 CHIMNEYS Metalbestoa Div., William Wallace McQuay, Inc., 1236-1237 Modine Mfg. Co., 1240-1241 Niagara Blower Co., 1186 Patterson-Kelley Co., Inc., The, 1307 Refrigeration Economics Co., Inc., 1248 Refrigeration Engineering, Inc., 1316 Trane Co., The, 1246-1247 Worthington Corp., 1192 York Corp., 1193 COILS, Blast Aerofm Corp., 1301-1303 American Blower Corp., 1272-1273 Bayley Blower Co., 1321 . Brown Products Co., 1446 Co., 1498-1499 Drayer-Hanson, Inc., 1181 GAO Mf$. Co., The, 1305 ... R.S, Combination for Hastings Air Conditioning Co., Inc., ^Natural and LP Gases CIRCULATORS, Hot Water 1185 ^jJ;\MueIler Furnace Co., 1200-1201 Heating Kennard Corp., 1235 ,,_lejhon;Mfg. Co., 1500 Bell A Gossett Co., 1516-1517 Kritzer Radiant Coils, Inc., 1464 gJphpEnk Co., 1502-1503 Chicago Pump Co., 1524-1525 Mario Coil Co., 1314 Crane Coy 1448-1449 McCord Corp., 1238 Hoffman Specialty Mfg. Corp., 1544 McQuay, Inc.. 1238-1237 Burners. Combination Gas 1547 Modine Mfg. Co., 1240-1241 ^lou -~ock. A Wilcox Co., The, 1466 saver-Brooks Co., 1467, 1495 ea.Co., 1496 iwey-Shepard Boiler Co., 1471 Engine A Machinery -Cki Burner Div., Sub. of General -Metals Corp., 1507 ^Johnson Co., 1508-1509 HOnA Sembower, Inc., 1478 Burner Co., 1510-1511 SB*' Rayfield Co., 1512 MBPon Mfg. Co., 1500 Burner Co., The, 1501 Engineering Co., The, 1509 *TMpley, Inc., 1513 Kraissl Co., Inc., The, 1530 Jas. P. Marsh Corp., 1552-1553 Minneapolis-Honeywell Regulator Co., 1428-1429 National Radiator Co., The, 1452 1454 Taco Heaters, Inc., 1519 H. A. Thrush A Co., 1526-1521 Trane Co., The, 1246-1247 United States Radiator Corp., 1458 1459 CLEANERS, Air (See Air Cleaning Equipment) Moore Dry Kiln Co.. 1306 D. J. Murray Mfg. Co., 1239 John J. Nesbitt, Inc., 1244-1245 New York Blower Co., The, 1341 Niagara Blower Co., 1186 Refrigeration Economics Co., Inc., 1248 Rome-Turoey Radiator Co., The, 1309 Trane Co., The, 1246-1247 # United States Air Conditioning Corp., 1190 Vulcan Radiator Co.{ The, 1310 - Westinghouse Electric Corp., Sturtevant Div., 1353 Young Radiator Co., 1252 WhOiZink Co., 1502-1503 CLEANERS. Flue (See Flue Cleaners) COILS, Brass ^P^NERS, Gas (See Goa Burners) Arthur Harris A Co., 1406 Mario Coil Co., 1314 COAL BURNERS (See Burners, McQuay, Inc., 1236-1237 ffiWIBRS. OU (See oa Burner,) Automatic) Trane Co., The, 1246-1247 j^SJklNG. Building COATINGS Armstrong Cork Co., 1587 jgttJlCsrey Mfg. Co., The, 1580- Miracle Adhesives Corp., 1570 - ^/Vent Flue ul,-?dert Co., The, 1359 COATINGS, Protective Philip Carey Mfg. Co., The, 1586' >581 JggV'* ^niintTi Wallace Insul-Mastic Corp. of America, 1584 COILS, Cooling Aerofm Corp., 1301-1303 Airtemp Div., Chrysler Corp., 1196 1197 American Blower Corp., 1272-1273 Drayer-Hanson, Inc., 1181 Edwards Engineering Corp., 1304 Frick Co., 1313 Frigidaire, Div. of General Motors, "^Ventilatcr Co., 1364 COILS, Aluminum Aerofm Corp., 1301-1303 RJR?ON, Activated Drayer-Hanson, Inc., 1181 IRurfiAir Div., BimpW^>.or.ou Mario Coil Co., 1314 |gp-i 1268-1269 5arncbey-Cheney McQuay. Inc., 1236-1237 ' John J. Nesbitt, Inc., 1244-1245 ^ Niagara Blower Co., 1186 EmSTGS- Bronie and Nickel Pa,3mrSOn'Kell,!y Co'- InC- The' Egjhnr Harris A Co 1406 Refrigeration Economics Co., Inc., BBp/-; . Rome-Turney Radiator Co., The, ?,,LAS?- XNSULA- tS Co,, The, 1246-1247 @Ui). / nsulation, Cellular United States Air Conditioning Corp., 1190 GAO Mfg. Co., The, 1305 Arthur Harris A Co., 1406 Hustings Air Conditioning Co., Inc., 1185 Kennard Corp., 1235 Kritzer Radiant Coils, Inc., 1464 Mario Coil Co., 1314 McCord Corp., 1238 McQuay, Inc., 1236-1237 Modine Mfg. Co., 1240-1241 Moore Dry Kiln Co., 1306 D. J. Murray Mfg. Co.. 1239 John J. Nesbitt, Inc., 1244-1245 New York Blower Co., The, 1341 . Niagara Blower Com 1186 Patteraon-Kelley Co., Inc., The, 1307 Please mention THE GUIDE 1954 when writing to Advertisers Mm 1146 1954 Grid Refrigeration Economies Co., Inc., Johnson Service Co., 1422-1423 Durant International Corp., 1 1248 Joy Mfg. Co., 1336-1337 1573 ' ' Refrigeration Engineering, Inc., Minneapolia-HoneyweU Regulator H. W. Porter A Co., Inc., 1574 1316 Co., 1428-1429 Reid Hayden Inc., 1574 Rome-Turaey Radiator Co., The, Nash Engineering Co., 1528-1529 Rio-wiL Co., The, 1575 1309 Worthington Corp., 1192 ----- Trane Co., The, 1248-1247 United States Radiator Carp., 1458 CONDUITS. Underground 1 1459 \ Westinghouse Electric Corp., Air Conditioning Dir., 1353 Worthington Corp., 1192 York Corp., 1193 Young Radiator Co., 1252 COMPRESSORS. Refrigeration Airtemp Div., Chrysler Corp., 1196 1197 Brunner Mfg. Corp., 1311 Carrier Corp., 1178-1179 > Curtis Refrigerating Machine Div. Durant Insulated Pipe Co., * 1573 Durant International Corp., 1573 . H. W. Porter A Co., Inc., 1574 Reid Hayden Inc., 1574 of Curtis Mfg. Co., 1312 Frick Co., 1313 Rio-wiL Co., The, 1575 ' Z-Crete Div., Zonolite Co., 1576 COILS. Pipe, Copper Frigidsire, Div. of General Motors, Arthur Harris A Co.. 1406 1184 Kritzer Radiant Coils, Inc., 1464 General Electric Co., 1182-1183 CONTROL, Air Volume Dampers Niagara Blower Co,t 1186 Ingersoll-Rand, 1527 Air A Refrigeration Corp., 1171 -^fa Refrigeration Engineering, Inc., Ready Power Co., The, 1315 Air Control Products, Inc., 136$n| 1316 Schnacke, Inc., 1317 1371 M York Corp., 1193 Trane Co., The, 1246-1247 Air Devices, Inc., 1261, 1372 -if;3 Westinghouse Electric Corp., Air Anemostat Corp of America, 137 Conditioning Div., 1191 1375 COILS, Pipe, Iron - Worthington Corp., 1192 Barber-Colman Co., 1376, 1411 ' ' Acme Industries, Inc., 1300 York Corp., 1193 ` Duro-Dyne Corp.. 1400 B&yley Blower Co., 1321 Hart A Cooley Mfg. Co., 1380-13S1J Killebrew Engineering Carp., 1518 Johnson Service Co., 1422-1423 Kritzer Radiant Coils, Inc., 1464 CONCRETE INSERTS (See In Minneapolis-Honeywell Regulator! Niagara Blower Con 1186 serts, Concrete) Co., 1428-1429 . Refrigeration Engineering, Inc., Powers Regulator Co., The, 142 1316 1436 COILS, Pipe and Tube, Non* Ferrous Edwards Engineering Corp., 1304 McQuay, Inc., 1236-1237 Niagara Blower Co., 1186 Patterson A Kelley Co., Inc., The, 1307 . Refrigeration Economics Co., Inc., 1248 Refrigeration Engineering, Inc., 1316 Rome-Turney Radiator Co., The, 1309 CONPENSORS and EVAPORA TORS Acme Industries, Inc., 1300 American Blower Corp., 1272-1273 Baltimore Aireoil Co., Inc., 1289 Bell & Gossett Co., 1516-1517 Buffalo Forge Co., 1325 Carrier Corp., 1178-1179 _ Curtis Refrigerating Machine Div. of Curtis Mfg. Co., 1312 Drayer-Hanson, Inc., 1181 Edwards Engineering Corp., 1304 Farrar A Trefts, Inc., 1473 Foster Wheeler Corp., 1293 Frick Co., 1313 Register A Grille Mfg. Co., 1 Titus Mfg. Co., 1392-1393 Waterloo Register Co., 1399 Young Regulator Co., 1401 CONTROL, Boiler Water Level? Maid-O'-Mist, Inc., 1550-1551 McDonnell A Miller, Inc., 1490-149M Merooid Corp., The, 1427 " Sarco Co., Inc., 1558-1559 Warren Webster A Co., 1563--15 CONTROL EQUIPMENT, < G A O Mfg. Co., The, 1305 bustlon COILS, Stainless Steel Arthur Harris A Co., 1406 Mario Coil Co., 1314 Niagara Blower Co., 1186 Patterson-Kelley Co., Inc., 1307 Trane Co., The, 1246-1247 The, Halstead A Mitchell, 1294 Kennard Corp., 1235 Kewanee-Roes Corp., 1479-1483 Killebrew Engineering Corp., 1518 Mario Coil Co., 1314 McCord Corp., 1238 McQuay. Inc., 1236-1237 Niagara Blower Co., 1186 Barber-CoLman Co., 1376, 1411 Coen Co., 1496 Combustion Control Corp., 1413 . General Controls, 1418-1419 Illinois Engineering Co., 1548 Maxitrol Co., 1426 Mercoid Corp., The, 1427 Milwaukee Gas Specialty Co., Patterson-Kelley Co., Inc., The, Minneapolis-Honeywell ~ COILS. Tank Patterson-Kelley Co., Inc., The, 1307 Western Blower Co., 1352 1307 Ready Power Co., The, 1315 Refrigeration Economics Co., Inc., 1248 Refrigeration Engineering, Inc., Co., 1428-1429 National Radiator Co., The, 1 1454 PenD Controls, Inc., 1432 Perfex Corporation, 1433 1316 Simplex Mfg. Co.. 1438 COLLECTORS, Fly Ash American Air Filter Co., Inc., 1285 1267 American Blower Corp., 1272-1273 V. D. Anderson Co., The, 1534-1535 Detroit Stoker Co., 1488 Prat-Daniel Corp., 1228 Rome-Tumey Radiator Co., The, Webster Engineering Co., Tb 1309 White-Rodgers Electric Co., 1 Schnacke, Inc., 1317 Taco Heaters, lnc., 1519 Trane Co., The, 1246-1247 CONTROL EQUIPMENT. Tlmg United States Air Conditioning April Showers, Inc., 1569 ' Corp.. 1190 B&rber-Colman Co., 1376, 1411 Westinghouse Electric Corp., Air General Controls, 1418-1419 Conditioning Div., 1191 Minneapolis-Honeywell " ~ COMPOUNDS, Boiler Kewanee-Roes Corp., 1479-1483 Worthington Corp., 1192 York Corp.. 1193 Young Radiator Co., 1252 Co., 1428-1429 Penn Controls, Inc., 1432 Perfex Corp., 1433 COMPRESSOR MOTORS (flee Motors, Electric) COMPRESSOR TUBING, Flex ible (See Tubing, Flexible Metallic) COMPRESSORS, Air Brunner Mfg. Co., 1311 Cleaver-Brooks Co., 1467, 1495 _ Curtis Refrigerating Machine Div. of Curtis Mfg. Co., 1312 Ingersoll-Rand, 1527 CONDUIT, Non-Ferrous Metal CONTROLLERS AND American Brass Co., The, 1256-1257 TROL EQUIPMENT (See miditg and Temperature Con Alco Valve Co., 1410 CONDUIT, Refrigeration (See American Moistening Co., 1174 Hose, Flexible Metal, and Liquid Bahnson Co., The, 1176-1177 Goa, Vapor) Barber-Colman Co.. 1376, 1411 ; Combustion Control Corp., 1413 CONDUITS, Underground Fit tings CONTROLLERS, Pump Durant Insulated Pipe Co., 1572- Pump Controllers) 1573 C. A. Dunham Co., 1541-1543 Numerals following Manufacturers' Names refer to pages in the Catalog Data Section Index to Modern Equipment 1147 Fulton Sylphon Div.. The. Robert- Airtemp Div., Chrysler Corp., 1196- Baltimore Aireoil Co., Inc., 1289 show-Fulton Controls Co., 1416- 3^1417' General Controls, 1418-1419 -^Hoffman Specialty Mfg. Corp., -3^1544^1547 . Hubbell Corp., 1421 ^Illinois Engineering Co., 1548-1549 1197 . American Blower Corp., 1272-1273 American Coolair Corp., 1319 American Furnace Co., 1216 American Moistening Co., 1174 American Radiator A Standard Sanitary Corp., Sunbeam Air Bell A Gossett Co., 1516-1517 Bulks Mfg. Co.,1290-1291 "Brunner Mfg. C~o., 1311----Carrier Corp., 1178-1179 Drayer-H&nson, Inc., 1181 C. .A.....D...u...n..h..a...m.. wCo., 1541-1543 Fluor Corp., Ltd., The, 1292 uLeslie Co., 1425 "*Jas;;P. Marsh Corp., 1552-1553 Conditioner Div., 1194-1195 Apnl ShowerB, Inc., 1569 Foster Wheeler Corp., 1293 Frick Co., 1313 ^Mercoid Corp., The, 1427 Hall A Gossett Co., 1516-1517 Fngidaire, Div. of General Motors. _.MinneapoIis-HoneyweIl Regulator Bishop A Babcock Mfg. Co., The, 1184 . -Jfe-Co., 1428-1429 (Massachusetts Blower Div.), 1322 General Electric Co., 1182-1183 ^Parks-Cramer Co., 1188-1189 Brown Products Co., 1446 Halstead A Mitchell, 1294 'vPehn Controls, Inc., 1432 ' Perfex Corporation, 1433 Brunner Mfg. Co., 1311 Bueusod-Stacey, Inc., 1175 Hastings Air Conditioning Co., Inc., ^ Photoswitch, Inc., (Affiliate of Com- Buffalo Forge Co., 1325 Keon&rd Corp., 1235 fni'iv'bustion Control Corp.), 1413 Carrier Corp., 1178-1179 Kewanee-Ross Corp., 1479-1483 -^powers Regulator Co., The, 1434- '^1436 Clarage Fan Co., 1180, 1329 DeBothezat Fans Div., American Killebrew Engineering Corp., 1518 Libe-Hoffmann Cooling Towers. l&Sarcotherm Controls, Inc., 1557 Machine A Metals, Inc., 1330 Inc., 1295 "^Simplex Mfg. Co., 1438 Drayer-Hanson, Inc., 1181 Maxley Co., The, 1296 ^ Sterling. Inc., 1440 Farr Co., 1276-1277 Mario Coil Co., 1314 ^Taylor Instrument Cos., 1441 Frigidsire, Div. of General Motors, McQuay, Inc., 1236-1237 _ ;Wesax Electric Heater Co., 1254 ^;White-Rodgers Electric Co., 1442 1184 General Electric Co., 1182-1183 Modine Mfg. Co., 1240-1241 National Radiator Co., The, 1452 w Halstead A Mitchell, 1294 1454 Ingereoll Products Div., Borg-War- John J. Nesbitt, Inc., 1244-1245 ^CONTROLS, Water Level ^'Leslie Co., 1425 ' Maid-O'-Mist, Inc.. 1550-1551 ner Corp., 1603 Joy Mfg. Co., 1336-1337 Kewanee-Ross Corp., 1479-1483 Niagara Blower Co., 1186 Patterson-Kelley Co., Inc.. The. 1307 McDonnell A Miller, Inc., 1490-1493 Mario Coil Co.. 1314 Merooid Corp., The, 1427 McQuay, Inc., 1236-1237 J. F. Pritchard A Co., 1297 Ready Power Co., The, 1315 L. J. Mueller Furnace Co., 1200-1201 Refrigeration Economics Co.. Inc.. D. J. Murray Mfg. Co., 1239 1248 # iCONVECTION HEATERS Airtherm Mfg. Co., 1229 Niagara Blower Co., 1186 _P_a_r_k_s_-_C__ra__m_e__r_C__o._,_1_1_8_8_-_1_1_89_ Refrigeration Engineering. Inc.. 1316 American Radiator A Standard Ready Power Co. 'The, 1315 Sante Fe Tank A Tower Co., 1298 Sanitary Corp., 1444-1445 C. A. Dunham Co., 1541-1543 Refrigeration 1248 Economics Co., Inc., Servel, Inc., 1204-1205 Sterling, Inc., 1440 Kntser Radiant Coils, Inc., 1464 Refrigeration Engineering. Inc., Taco Heaters. Inc., 1519 Modine Mfg. Co., 1246-1241 1316 Trane Co., The, 1246-1247 '1454^ Radiator Co* The 1452~ John J. Nesbitt, Inc., 1244-1245 Rome-Turney Radiator Co.. The. 1309 Shaw-Perkins Mfg. Co., 1465 Trane Co., The, 1246-1247 oS.erve,l,- In. c., 1204-1205 _ Standard Electric Mfg. Co., 1347 Surface Combustion Corp., 12061207 Trane Co., The, 1246-1247 United States Air Conditioning United states Air Conditioning Corp., 1190 Westinghouse Electric Corp., Air Conditioning Div., 1191 C. H. Wheeler Mfg. Co., 1533 Worthington Corp., 1192 United States Radiator Corp.. H58- United States Radiator Corp., 1458- YoungfUdiatOT Co.. 1252 1*4*5"9 Webster & Co.. 1562-1564 WBn Electric Heater Co., 1254 Ldwm L. Wiegand Co., 1255 xoung Radiator Co., 1252 CONVECTORS AND CONVEC. TOR ENCLOSURES Acme Industries, Inc., 1300 Antherm Mfg. Co., 1229 . American Rndiator & Standard Sanitary Corp., 1444-1445 "own Products Co., 1446 Crane Co.. 1446-1449 fcA; Dunham Co., 1641-1543 PeddOT-Onigan Corp.. 1231 it * o Mig. Co., The, 1305 S2i?er Radiant Coila, Ine., 1464 STMne Mfg. Co.. 1240-1241 '* 1454 Radiator Co., The, 1452- 1459 Utility Appliance Corp., 1208-1209 Westinghouse Electric Corp., Air Conditioning Div., 1191 Worthington Corp., 1192 York Corp., 1193 Young Radiator Co., 1252 COOLING EQUIPMENT, OU Acme Industries, Inc., 1300 Aerofin Corp., 1301-1303 American District Steam Co., Ine.. 1402-1403 Bell A Gossett Co., 1516-1517 Bulks Mfg. Co.. 1290-1291 Brunner Mfg. Co., 1311 Kewanee-Ross Corp., 1479-1483 Marley Co., The, 1296 Mario Coil Co., 1314 Niagara Blower Co., 1186 COOLING TOWER FANS DeBothezat Fans Div., American Machine A Metals, Inc., 1330 Fluor Corp., Ltd., The, 1292 Halstead A Mitchell, 1294 Hartseli Propeller Fan Co., Div. of Castle Hills Corp., 1333 Joy Mfg. Co., 1336-1337 Lau Blower Co., The, 1338-1339 Lilie-Hoffmann Cooling Towers, Inc., 1295 Marley Co., The. 1296 J. F. Pritchard A Co., 1297 United States Air Conditioning Corp., 1190 L. J. Wing Mfg. Co., 1249-1251 COOLING TOWERS. Atmos Herman to i tD-.i.v., . American Air jXrf S'! Ino-l 1242-1243 TKw ' Ine-, 1244-1245 Cm?., The. 1308 "^"-Turney Radiator Co., The, gaw-Perldna Mfg. Co., 1465 Stani^R?' l2!2-i283 ' Co7l390StoPm * PerforaUn fe? ^> i.The. 1245-1247 Patterson-Kelley Co., Inc., The, 1307 ' ' ' Ready Power Co., The, 1315 Refrigeration Economics Co.. Inc.. 1248 Refrigeration Engineering, Inc., 1316 Sterling, Inc., 1440 Trane Co.. The, 1246-1247 Worthington Corp., 1192 Young Radiator Co., 1252 pheric, Mechanical Draft* Forced Draft, Induced Draft (See also Coding Equipment, Water) Acme Industries, Inc., 1300 Air A Refrigeration Corp., 1171 American Blower Corp., 1272-1273 Baltimore Aireoil Co., Inc., 1289 Binks Mfg. Co., 1290-1291 Buensod-Stacey, Inc., 1175 Carrier Corp., 1178-1179 Curtis Refrigerating Machine Div. ---- of Curtis Mfg. Co.. 1312 ` >diator Corp., 1458- COOLING EQUIPMENT. Water Drayer-Hanson, Inc., 1181 (See also Water Coding) Fluor Corp., Ltd., The, 1292 Acme Industries, Inc., 1300 Foster Wheeler Corp., 1293 Aerofin Corp., 1301-1303 Halstead A Mitchell, 1294 Airtemp Div., Chrysler Corp., 1196- Kennard Corp.. 1235 1197 .L..i.l.i.e...-.H.. o-ffmann C-ooling Towers, American District Steam Co., Inc.. Inc., 1295 1402-1403 Marley Co., The, 1296 Please mention THE GUIDE 1954 when writing to Advertisers Mario CoO Co., 1314 McQuay, Inc.. 1236-1237 D J. Murray Mfg. Co., 1239 J. F. Pritchard A Co., 1297 Refrigeration Engineering, Inc., 1316 Saute Fe Tank A Tender Co., 1298 Servel, Inc., 1204-1205 C. H. Wheeler Mfg. Co., 1633 DAMPER REGULATORS. Fur nace -- -. Field Control Div. of H. D. Conkey A Co., 1415 General Controls, 1418-1419 Hart A Cooley Mfg. Co., 1380-1381 earner v^arp., Clarage Fan Co., 1180, 1329 .. Frigidaire, Div. of General Mo 1184 " CORK PRODUCTS (S Imu- Mercoid Corp^ The, 1427 Mario Coil Co., 1314 . lotion) Minneapolis-Honeywell Regulator New York Blower Co., The, 1341 Armstrong Cork Co., 1587 Co., 1428-1429 Niagara Blower Co., 1186 Mundet Cork Corp., 1597 Penn Controls, Inc., 1432 Parks-Cramer Co., 1188-1189 Perfex Corp., 1433 Pittsburgh Lectrodryer Corp., 11 Simplex Mfg. Co., 1438 J. F. Pritchard & Co., 1297 ; CORROSION, Treatment of United States Register Co., 1396 Ready Power Co., The, 1315 .. American Gilsonite Co., 1571 1397 Refrigeration Engineering, Ii Durant Insulated Pipe Co., 1572-- 1316 1573 . Surface Combustion Corp., 12 Durant International Corp., 1572 DAMPERS, Air Volume Control 1207 ~ 1573 Air Control Products, Inc., 1368 Trane Co., The, 1246-1247 . Insul-Mastic Corp. of America, 1584 1371 United States Air Conditio-' Owens-Coming Fiberglas Corp., Air Devices, Inc., 1261, 1372 Corp., 1190 . 4 .i 1585 Rio-wiL Co., The, 1575 Aladdin Heating Corp., 1318 Viking Air Conditioning Corp.^1 American Foundry A Furnace Co., Westinghouse Electric Corp., St' 1214-1215 tevant Div., 1353 ft Anemoetat Corp. of America, 1374 York Corp., 1193 4 COVERING, Pipe and Surface American Gilsonite Co., 1571 Armstrong Cork Co., 1587 Philip Carey Mfg. Co., The, 1580 1581 ^ Durant Insulated Pipe Co., 1572 1573 . Durant International Corp., 1572 1573 Glass Fibers, Inc., 1582 Gustin-Bacon Mfg. Co., 1583 Infra Insulation, Inc., 1602 Insul-Mastic Corp. of America, 1584 Johna-Manville, 1592-1593 Kimberly Clark Corp., 1594-1595 Lockport Cotton Batting Co., 1596 Mundet Cork Corp., 1597 Owens-Corning Fiberglas Corp., 1375 Barber-Colman Co., 1376, 1411 Hart A Cooley Mfg. Co., 1380-1381 Johnson Service Co., 1422-1423 Minneapolis-Honeywell Regulator Co., 1428-1429 Parks-Cramer Co., 1188-1189 Perfex Corp., 1433 Powers Regulator Co., The, 1434 1436 Register A Grille Mfg. Co., Rittling Corp., The, 1308 Titus Mfg. Corp., 1392-1393 Tuttle A Bailey, Inc., 1394-1395 United States Register Co., 1396 1397 . ,, Waterloo Register Co., Inc., 1399 Young Regulator Co., 1401 DEHYDRATORS, Refrigerant Henry Valve Co., 1420 "* DESTROYERS, Soot (See ;S Destroyers) ' DETECTORS, Smoke (See Si Detectors and Indicators, for Fland Ducts) DIFFUSERS. Air (See Air JHf; fusers, and Ventilators, Floor;, ~ Wall) 1585 . Owens-Illinois Glass Co., 1577 Pittsburgh Corning Corp., 1579 H. W. Porter A Co., Inc., 1574 Reid Hayden, Inc., 1574 DAMPERS, Back Draft (See DISCS, Removable Compos!tio Dampers, Air Volume Control) Fairbanks Co., The, 1566 ' Jenkins Bros., 1568 Rio-wiL Co., The, 1575 Sprayo-Flake Insulation Co., 1586 United States Gypsum Co., 1599 Z-Crete Div., Zonolite Co., 1576 DAMPERS, Mechanical Bahnson Co., The, 1176-1177 Barber-Colman Co., 1376, 1411 Buensod-Staoey, Inc., 1175 DISTRICT HEATING (See Cr rosion, Treatment of--Expant*Joints--Insulation, Underground: CUT-OFFS, Low Water Barber-Colman Co., 1376, 1411 General Controls, 1418-1419 Maid-O'-Mist, Inc., 1550-1551 McDonnell A Miller, Inc., 1490-1493 Mercoid Corpy The, 1427 Minneapolis-Honeywell Regulator Co., 1428-1429 National Radiator Co., The, 1452 1454 Warren Webster A Co., 1562-1564 Duro-Dyne Corp., 1400 Minneapolis-Honeywell Regulator Co., 1428-1429 Perfex Corp., 1433 Powers Regulator Co., The, 1434 1436 Young Regulator Co., 1401 DAMPERS, Multi-Blade. Hard ware . Duro-Dyne Corp., 1400 Meters, Pipe) DISTRICT HEATING, . temperature Fluid Systems^ American Gilsonite Co., 1571 Durant Insulated Pipe Co., '15 1573 ; Durant International Corp., 1. 1573 Z-Crete Div., Zonolite Co., 1576.. DAMPER REGULATOR SETS Air Control Products, Inc., 1368-1371 Barber-Colman Co.. 1376, 1411 Duro-Dyne Corp., 1400 Field Control Div, of H. D. Conkey A Co., 1415 . Hart A Cooley Mfg. Co., 1380-1381 Mercoid Corp., The, 1427 Minneapolis-Honeywell Regulator Co., 1428-1429 National Radiator Co., The, 1452 1454 Pehn Controls, Inc., 1432 Perfex Corp.. 1433 Tuttle & Bailey, Ine. 1394-1395 Young Regulator Co., 1401 DAMPER REGULATORS, Boiler (See Regulators) Minneapolis-Honeywell Regulator Co., 1428-1429 DEFLECTION GRILLE (See Grilles, Registers and Ornamental Metal Work, also Louvers, Registers) Air Control Products, lnc., 1368 1371 Auer Register Co., The, 1373 Barber-Colman Co., 1376, 1411 Hart A Cooley Mfg. Co., 1380-1381 Hendrick Mfg. Co., 1382-1383 Register 6c Grille Mfg. Co., 1389 _ Standard Stamping A Perforating Co., 1390 Titus Mfg. Corp., 1392-1393 Tuttle A Bailey, Inc., 1394-1395 United States Register Co., 1396 1397 Waterloo Register Co., 1399 * Young Regulator Co., 1401 DEHUMIDIFIERS Air A Refrigeration Corp., 1171 DRAFT APPARATUS (See Bl% era. Forced Draft) - DRAFT CONTROL, Barome Field Control Div. of H. D. Co , A Co.. 1415 National Radiator Co., The, 1. 1454 K Perfex Corp., 1433 Simplex Mfg. Co.t 1438 'a :t Webster Engineering Co., low DRYING EQUIPMENT Air Devioes, Inc., 1261, 1372 Buffalo Force Co., 1325 .. Campbell Heating Co., 1218-121 Dravo Corp., 1222-1223 ^ Electromode Corp., 1253 JackBon A Church Co., 1224 ^ Lau Blower Co., The, 1338-1339 Numerals following Manufacturers* Names refer to pages In the Catalog Data Section ^fiis^Co-S 1240-1241 OOTS'Dry Kiln Co., 1306 'ationaLGeater Co., 1226 Niagara Blower Co., 1186 AJtimriAvOlson A Co., 1227 evCo., The, 1246-1247 Trane Co., The, 1246-1247 United States Air Conditioning Corp., 1190 Westinghouse Electric Corp., Air Conditioning Div., 1191 - Young Radiator Co., 1252 UCT INSULATION (See Insu lation, i-Duets, Ventilating, Air Conditioning) Si?, : - UCTS/Prefabricated juHp Carey Mfg. Co., The, 1580 1581' ' ohna^Manville, 1592-1593 IivJ.r-;Mueller Furnace Co., 1200-. i2or . ,, United^ States Register Co., 1396 1397 s*. . UST: COLLECTING EQUIP MENT American Air Filter Co., Inc., 1265- ~-1267i* American Blower Corp., 1272-1273 V*D; Anderson Co., The, 1534-1535 Buffalo Forge Co., 1325 Clarage Fan Co., 1180, 1329 General Blower Co., 1332 Sheldons Engineering Ltd., 1346 iioh,-lno.. 1285 Sson A Co., Inc., 1288 tTUySpTe COLLECTORS, doth _mencan Air Filter Co., Inc.. 1265 -1267. 4S-" EJECTORS, Sewage tiffalo Pumps, Inc.. 1523 (Chicago Pump Co., 1524-1525 ELECTROSTATIC AIR ?CLEANERS An>Mase Corp., 1262-1263 Air Filter Co., Inc., 71268-1287 merican Radiator A Standard Sanitary Corp., Sunbeam Air -Conditioner Div., 1194-1195 gWer Corp., 1274-1275 Mon, Inc., 1285 Westmghouse Electric Corp.. Sturf^.tevant Div., 1287 EXHAUST HEADS (Sec Heads, Exhaust) EXHAUST TUBING. Flexible (See Tubing, Flexible, Metallic) EXHAUSTERS Air Devices, lnc., 1261, 1372 Allen Ventilator Div., Production Planning Co., 1368 American Blower Corp., 1272-1273 American Coolair Corp., 1319 Bayley Blower Co., 1321 G. C. Breidert Co., 1359 Brundage Co., The, 1324 Buffalo Forge Co., 1325 Century Fan A Ventilator Co., 1326 Champion Blower A Forge Co., 1327 Chicago Blower Corp., 1328 Clarage Fan Co., 1180,1329 DeBothezat Fans Div., American Machine A Metals. Inc., 1330 Gallaher Co., The, 1360 Garden City Fan Co., 1331 General Blower Co., 1332 H&rtzell Propeller Fan Co., Div. of Castle Hills Corp., 1333 Hunter Fan A Ventilating Co., 1334 Xlg Electric Ventilating Co., 1234, 1335 Joy Mfg. Co., 1336-1337 Lau Blower Co., The, 1338-1339 Muckle Mfg. Co., 1363 John J. Nesbitt, lnc., 1244-1245 New York Blower Co., The, 1341 Peerless Electric Co., The, 1342 Penn Ventilator Co., 1364 Propellair Div., Robbins A Myers, Inc., 1343 Reed Unit-Fans, Inc., 1344 Sheldons Engineering Ltd., 1346 Swartwout Co., The, 1365 Trade-Wind Motorfans, lnc., 1350 Trane Co., The, 1246-1247 _ United States Air Conditioning Carp., 1190 Westmghouse Electric Corp., Stur- tevant Div., 1287,1353 L. J. Wing Mfg. Co., 1249-1251 JJ^CTROSTATIC Gas Tnon, Inc., 1285 FILTERS, EXHAUSTERS. Laboratory Fume Gallaher Co., The, 1360 E. H. Sheldon Equipment Co., M MOTORS. Air 136W3K Maid-O'-Mist, Inc., 1550-1551 - f EXPANSION JOINTS Ev&pnn.^nn, American District Steam Co., Inc., CONDENSERS 1402-1403 Condensers and Evaporators) Badger Mfg. Co., 1404 Celotex Corp., The, 1588 evaporators tSL " Gosaett Co., 1516-1517 Malo Forge Co., 1325 i^a-Haraon, Ino., 1181 * Trefle, lnc., 1473 Wheeler 6orp., 1293 Mrf-1 S'S Co., 1314 Corp., 1238 gfgyay, Inc., 1238-1237 Xj^g^tion Economics Co., Inc., Flexonics Corp., Expansion Joint Div., (Formerly Chicago Metal Hose Corp.), 1405 Foster Wheeler Corp., 1293 Fulton Sylphon Div., The, Robertshaw-Fulton Controls Co., 1418 1417 Illinois Engineering Co., 1548-1549 Owens-Coming Fiberglas Corp., 1585 Warren Webster A Co., 1562-1564 Yarnall-Waring Co., 1561 Engineering, Inc., i|j*"-Tumey Radiator Co., The, EXPANSION LOOPS l9;Hitere,Ine.,1519 touto*ed PipB Co ' I572` Durant International Corp., 1572 1573 Rie-wiL Co., The, 1575 Z-Crete Div., Zonolite Co., 1576 EXPOSITIONS International Exposition Co., 1514 FAN BLADES Brookside Products Co.,Inc., 1323 Standard Electric Mfg. Co., 1347 Torrington Mfg. Co., The, 1348-1349 FAN COOLER Utility Appliance Corp., 1208-1209 FAN MOTORS (See Motors, Elec tric) FAN STACKS . Dutton Boilers, Division Hapman- Dutton Co., 1472 FANS, Attic Allen Ventilator Div., Production Planning Co.. 1368 American Blower Corp., 1272-1273 American Coolair Corp., 2319 Buffalo Forge Co., 1325 Philip Carey Mfg. Co., The, 1580 1581 Champion Blower A Forge Co., 1327 General Blower Co., 1332 Hunter Fan A Ventilating Co., Inc., 1334 Ug Electric Ventilating Co., 1234, 1335 Lau Blower Co., The. 1338-1339 Muckle Mfg. Co.. 1363 Peerless Electric Co., The, 1342 Reed Unit-Fans, Inc., 1344 H. J. Somers, Inc., 1282-1283 Standard Electric Mfg. Co., 1347 Torrington Mfg. Co., The, 1348-1349 Trade-Wind Motorfans, lnc., 1350 Viking Air Conditioning Corp., 1351 John Zink Co., 1502-1503 FANS. Axial Flow Allen Ventilator Div., Production Planning Co., 1368 American Blower Corp., 1272-1273 American Coolair Corp., 1319 Bahnson Co., The, 1178-1177 Buffalo Forge Co., 1325 Century Fan A Ventilator Co., 1326 Chicago Blower Corp., 1328 DeBothezat Fans Div., American Machine A Metals, Inc., 1330 Gallaher Co., The, 1360 Hartzell Propeller Fan Co., Div. of Castle Hills Corp., 1333 Hunter Fan A Ventilating Co., 1334 Ug Electric Ventilating Co., 1234, 1335 Joy Mfg. Co., 1336-1337 Lau Blower Co., The, 1338-1339 New York Blower Co.. The. 1341 Peerless Electric Co., The, 1342 Penn Ventilator Co., 1364 Propellair Div., Robbins A Myers, Inc., 1343 Reed Unit-Fans, Inc., 1344 Westinghouse Electric Corp., Stur- tevant Div., 1287 L. J. Wing Mfg.-Co., 1249-1251 FANS, Centrifugal Aladdin Heating Corp., 1318 American Blower Corp., 1272-1273 Please mention THE GUIDE 1954 when writing to Advertisers 1150 1954 Guide. American Foundry A Furnace Co., Champion Blower A Forge Co., 1327 Century Fan A Ventilator Co., 1325 ' 1214-1215 Clarage Fan Co., 1180, 1329 Champion Blower A Forge Co., 1327 .. ' Bayley Blower Co., 1321 DeBothexat Fans Div., American Chicago Blower Corp., 1328 > Bishop A Babcock Mfg. Co., The, Machine A Metals, Inc., 1330 DeBothexat Fans Div., American.. (Massachusetts Blower Div.), 1322 Gallaher Co., The, 1360 Machine A Metals, Inc-, 1330 ' Brookside Products Co., Inc., 1323 Brundage Co., The, 1324 - Buffalo Forge Co., 1325 ' E. K. Campbell Co., 1217 . Garden City Fan Co.. 1331 Gallaher Co., The, 1360 General Blower Co., 1332 - .. Garden City Fan Co., 1331 Muckle Mfg. Co., 1363 General Blower Co., 1332 .. Westinghouse Electric Corp, Stur- HartzeU PropeUer Fan Co., Div. of i, Century Fan A Ventilator Co., 1326 tevant Div., 1287 Champion Blower A Forge Co., 1327 L. J. Wing Mfg. Co., 1249-1251 Castle Hills Corp., 1333 Hirechman-Pohle Co., Inc., 1361 Chicago Blower Corp., 1328 Clarage Fan Co., 1180, 1329 Cleaver-Brooks Co., 1467, 1495 Gallaher Co., The. 1360 Garden City Fan Co., 1331 General Blower Co.. 1332 HartxeU Propeller Fan Co., Div. of Castle Hills Corp., 1333 Hastings Air Conditioning Co., Inc., 1185 Hirechman-Pohle Co., Inc., 1361 FANS, Portable American Coolair Corp., 1319 Brookside Products Co., Inc., 1323 Champion Blower A Forge Co., 1327 Chicago Blower Corp., 1328 General Blower Co.. 1332 Hartnell Propeller Fan Co., Div. of Castle Hills Corp., 1333 Hunter Fan A Ventilating Co., Ine., Hunter Fan A Ventilating Co., Inc.;. 1334 <! Hg Electric Ventilating Co., 1234: 1335 Joy Mfg. Co., 1336-1337 Lau Blower Co., 1338-1339 Muckle Mfg. Co., 1363 Herman Nelson Div., American Air< Filter Co., Inc., 1242-1243 New York Blower Co., The, 1341 Niagara Blower Co., 1186 Ilg Electric Ventilating Co., 1234, 1335 Morrison Products, Ine., 1340 L. J. Mueller Furnace Co., 1200-1201 Herman Nelson' Div., American Air Filter Co., Inc., 1242-1243 New York Blower Co., The, 1341 Niagara Blower Co., 1186 Peerless Electric Co., The, 1342 Penn Ventilator Co., 1364 Revcor, 1345 Standard Electric Mfg. Co., 1347 Torrington Mfg. Co., The, 1348-1349 1334 Ilg Electric Ventilating Co., 1234, 1335 Lau Blower Co., The 1338-1339 Propeliair Div., Robbins A Myere, Ine., 1343 Reed Unit-Fans, Inc., 1344 Standard Electric Mfg. Co., 1347 Torrington Mfg. Co., The, 1348-1349 L. J. Wing Mfg. Co., 1249-1251 FANS, Propeller Peerless Electric Co., The, 1342 Penn Ventilator Co., 1364 . Propeliair Div., Robbins A Myere, Inc., 1343 " Reed Unit-Fans, Inc., 1344 . Standard Electric Mfg. Co., 1347 Trane Co., The, 1246-1247 ^ United States Air Conditioning Corp., 1190 >' Viking Air Conditioning Corp., 1351'f Westinghouse Electric Corp., Stur? tevant Div., 1287 ' L. J. Wing Mfg. Co.. 1249-1251 Trade-Wind Motorfans, Inc., 1350 Trane Co., The, 1246-1247 United States Air Conditioning Corp., 1190 Utility Fan Corp., A Div. of Utility Appliance Corp., 1210 Allen Ventilator Div., Production Planning Co., 1368 American Blower Corp., 1272-1273 American Coolair Corp., 1319 Bishop A Babcock Mfg. Co., The, (Massachusetts Blower Div.), 1322 FANS, Attic, etc.) Ventilating Axial Flow, (See Fans; Centrifugal?, " Western Blower Co.,1352 Brookside Products Co., Inc., 1323 Westinghouse Electric Corp., Stur- Buffalo Forge Co., 1325 FEED WATER HEATERS (See tevant Div., 1287 Century Fan A Ventilator Co., 1326 Heaters, Feed Water) Chicago Blower Corp., 1328 ' Clarage Fan Co., 1180, 1329 _ FANS, ELECTRIC American Coolair Corp., 1319 DeBothezat Fans Div., American FEED WATER REGULATORS Machine A Metals, Inc., 1330 (See Regulators, Feed Water) Philip Carey Mfg. Co., The, 1580 1581 Champion Blower A Forge Co., 1327 General Blower Co., 1332 Hirechman-Pohle Co., Inc., 1361 Hunter Fan A Ventilating Co., Inc.. 1334 Hg Electric Ventilating Co., 1234, 1335 ' Lou Blower Co., The. 1338-1339 Propeliair Div., Robbins A Myere, Inc., 1343 Standard Electric Mfg. Co., 1347 Gallaher Co.. The, 1360 General Blower Co.. 1332 HartzeU Propeller Fan Co., Div. of Castle Hills Corp., 1333 Hirechman-Pohle Co., Inc., 1361 Hunter Fan A Ventilating Co., Inc., 1334 Ilg Electric Ventilating Co., 1234, 1335 Lau Blower Co., The, 1338-1339 Muckle Mfg. Co., 1363 Herman Nelson Div., American Air Filter Co., Inc., 1242-1243 FEEDERS, Boiler Water Cyclotherm Div., U. S. Radiator. Corp., 1470 ` Maid-O-Mist, Inc., 1559-1551 MeDonneU A Miller, Inc., 1490-1493 Penn Controls, Inc., 1432 V Warren Webster A Co., 1562-1564 , FELT, Insulating (See Insulation Felt) Torrington Mfg. Co., The, 1348-1349 New York Blower Co., The, 1341 Trade-Wind Motorfans, Inc., 1350 Viking Air Conditioning Corp., 1351 Western Engineering & Mfg. Co., 1366 L. J. Wing Mfg. Co., 1249-1251 Peerless Electric Co., The, 1342 Penn Ventilator Co., 1364 J. F. Pritchard A Co., 1297 Propeliair Div., Robbins A Myere, Inc., 1343 Reed Unit-Fans, Inc., 1344 FELT, Sound Deadening Armstrong Cork Co.. 1587 _ Philip Carey Mfg. Co., The, 15. 1581 Glass Fibers. Inc., 1582 Revcor, 1345 Kimberly-Clark Corp., 1594-1595 FANS, Furnace Aladdin Heating Corp., 1318 American Blower Corp., 1272-1273 Torrington Mfg. Co., The, 1348-1349 Owens-Corning Fiberglaa Corp-i Trade-Wind Motorfans. Inc., 1350 1281, 1585 '*' Trane Co., The, 1246-1247 Wood Conversion Co., 1600 Bishop A Babcock Mfg. Co.. The, Viking Air Conditioning Corp., 1351 (Massachusetts Blower Div.), 1322 Western Blower Co., 1352 Brundage Co., The. 1324 Western Electric A Mfg. Co., 1366 FIBER INSULATION (See /& Champion Blower Forge Co., 1327 L. J. Wing Mfg. Co., 1249-1251 eviction) f Clarage Fan Co., 1180, 1329 DeBothexat Fans Div., American Machine A Metals, Inc., 1330 Joy Mfg. Co., 1336-1337 Morrison Products, Inc., 1340 L. J. Mueller Furnace Co., 1200-1201 United States Air Conditioning Corp., 1190 U J. Wing Mfg. Co., 1249--1251 FANS, Supply and Exhaust Aladdin Heating Corp., 1318 Allen Ventilator Div., Production Planning Co., 1358 American Blower Corp., 1272-1273 American Coolair Corp., 1319 Bayley Blower Co., 1321 Bishop A Babcock Mfg. Co., The FILTERS. Air (See Air Cleaning Equipment) Air A Refrigeration Corp., H71 Air Devices, Inc., 1261, 1372 Air Filter Corp., 1264 Air-Maxe Corp., 1262-1263 American Air Filter Co., Inc., lwjr 1267 ` (Massachusetts Blower Div.), 1322 American Moistening Co., 1174 ^ FANS INDUCED DRAFT American Blower Corp., 1272-1273 Bayley Blower Co., 1321 Buffalo Forge Co., 1325 Century Fan A Ventilator Co., 1326 Brookside Products Co., Inc., 1323 Brundage Co., The, 1324 BuffaloForge Co., 1325 Philip Carey Mfg. Co., The, 1580 1581 American Radiator A Standard Sanitary Corp., Sunbeam AJ? Conditioner Div., 1194-1195 V. D. Andereon Co., The, 1534-15 Bishop A Babcock Mfg. Co., Numerals following Manufacturers* Names refer to pages in the Catalog Data Section rtgflndex to Modern Equipment 1151 ? (Massachusetts Blower Div.), 1322 L- J. Mueller. Furnace Co.. 1500- Taylor Forge & Pipe WorkB. Ine.. Carey Electronic Engineering Co., ,, 1*08 : >-`1270 United States Register Co., 1396- Tube Turns. Inc.. 1409 - Continental Air Filters, Inc., 1271 1397 t -Dollinger Corp., 1274-1276 y Farx Co., 1276-1277 - Glasfloss, 1278 -/Goodyear Tire A Rubber Co., 1270 >.MucUe Mfg. Co., 1363 -'rOwena-Conung Fiberglaa Corp., >-.r 1281, 1585 .Research Products Corp., 1284 f;H. J. Somers, Inc., 1289-1283 --Trion, Inc., 1285 ^ Vortax Co.. 1286 Wilson A Co., Inc., 1288 ./FILTERS, Air, Continuous, Au '' temarie . v Air-Maxe Corp., 1262-1263 American Air Filter Co., Inc., 1265 ' 1287 FITTINGS, Hot Water Heating Systems Hammond Brass Works, 1567 Hoffman Specialty Mfg. Corp., 1544 1547 Jas. P. Marsh Corp.. 1552-1553 National Radiator Co., The, 1452 1454 Sarco Co.. Inc.. 1558-1559 Sarcotherm Controls, Inc., 1557 Taco Heaters, Inc., 1519 H. A. Thrush & Co- 1529-1521 Trane Co., The. 1246-1247 ' United States Radiator Corp., 1458-1459 Warren Webster A Co., 1562-1564 FITTINGS, Welding GrinneU Co., Ine.. 1232-1233 Iiftdiah Co., 1407 Taylor Forge A Pipe Works, Inc., 1408 Tube Turns, Inc., 1409 FLANGES, Galvanized or NonFerrous Ladish Co., 1407 Simplex Mfg. Co., 1438 FLANGES. Lead. Roof Simplex Mfg. Co., 1438 ` V. D. Andereon Co., The, 1534-1535 . Bahnson Co., The, 1176-1177 > Continental Air Filters, Inc., 1271 1 Dollinger Corp., 1274-1275 -.FarrCo., 1276-1277 fFfIiTrTnIwNGrcS, J,ac.keted Sc,team and. FLNAoNnG-FEeSrr,oHupse, Alloy,Stainless _ Parka-Cramer Co., 1188-1189 Ladish Co., 1407 Tube Turns, Inc., 1409 - , Charles E. Mannfng Co., 12&) '.'Trion, Ine., 1285 FILTERS, Electrostatic Preclpl- *?, tators FITTINGS, Pipe, Add Resisting Ladish Co., 1407 Taylor Forge A Pipe Works, Ine., 1408 FLANGES, Pipe Blind GrinneU Co.. Inc., 1232-1233 Ladish Co., 1407 Taylor Forge A Pipe Works, Inc., jg; Air-Maxe Corp., 1262-1263 **' American Air Filter Co., Inc., 1265 * 1287 Dollinger Corp., 1274-1275 Trion/inc., 1285 -%' Xi FriILLiTcEKRoS,. Guaas % Air-Maxe Corp., 1262-1263 ?,t American Air Filter Co., Inc., 1265 % 1287 *- V. D. Anderson Co., The, 1534-1535 Bamebey-Cheney Co., 1268-1269 FITTINGS, Pipe. Alloy and Stainless, Non-Ferrous Ladish Co., 1407 Taylor Forge A Pipe Works, 1408 Tube Turns, Inc., 1409 FITTINGS, Pipe, Flanged Grinnell Co.. Inc.. 1232-1233 Taylor Forge A Pipe Works, Inc., 1408 . York Corp., 1193 ' Tube Turns, Inc., 1409 FLANGES, Pipe, Reducing GrinneU Co., Inc., 1232-1233 Ladish Co., 1407 Taylor Forge A Pipe Works, Ine., 1408 Tube Turns, Inc., 1409 FLANGES, Pipe, Steel GrinneU Co., Ine., 1232-1233 *S>` ^ im- Ladish Co., 1407 'T. Dollhier Corp., 1274-1275 Cd3m-2m` Bar"bcy-Chei"y FITTINGS, Pipe ground Conduit for Under Taylor Forge A Pipe Works, Inc. 1408 Tube Turns, Inc., 1409 . Trion, Inc., 1285 Durant Insulated Pipe Co., 1572 1573 Durant International Carp., 1572 FLANGES, Welding FILTERS, Grease l&T***'Inc- 1261. 1372 #-.4? f^ter Corp., 1264 -U-y A-Mase Corp., 1262-1263 A^y*an Alr Filter Co., Inc., 1265 1573 H. W. Porter A Co., Inc., 1574 Reid Hayden, Inc., 1574 Rio-wiL Co., The, 1575 GrinneU Co.. Ino., 1232-1233 Ladish Co., 1407 Taylor Forge A Pipe Works, Inc., 1408 Tube Turns, Inc., 1409 S FDleruJuc.. 1271 1274-1275 Co., 1275-1277 V .Roaoarch Product. Corp., 1284 FITTINGS, Pipe, Galvanized GrinneU Co., Inc., 1232-1233 Ladisb Co., 1407 Taylor Forge A Pipe Works, Ine., 1408 ^_ FLOATS, Ferrous and Ferrous (Seamless) Arthur Harris A Co., 1406 'tli A?'uER^! Uquld Ths- 1262-1263 C?Tp ' 1274-1275 C Metal Specialty Co., 1505 ^ .uranal Co., Inc., The, 1530 - Odors - cS^ey/:h?ne7 Co., 1288-1289 FITTINGS, Pipe, Screwed GrinneU Co., Inc., 1232-1233 Henry Valve Co., 1420 Ladish Co., 1407 FITTINGS, Pipe, Seamless Weld ing Ladish Co., 1407 Tube Turns, Inc., 1409 FLOATS, Welded-Stainless, Mo nel. Plated Steel Arthur Harris A Co.. 1406 W. H. Nicholson A Co., 1554-1555 FLOOR PLATES National Radiator Co., The, 1452- United States Radiator Corp., 1458-1459 v' United States Steel, 1367 % Products Corp., 1284 FITTINGS, Pipe, Socket-Weld ing FLUE CLEANERS Ladish Co., 1407 Economy Flue Cleaner Co., 1494 FITTINGS. Pipe, Solder American Brass Co., The, 1256-1257 FLUE GAS ANALYSIS Minneapolis-Honeywell Regulator Co., 1428-1429 Conditioning FITTINGS, Pipe. Steel FLUES Metalbestos Div., William Wallace Co., 1498-1499 . Please mention THE GUIDE 1954 when writing to Adrertlsers FOOD SAVERS Delta Heating Corp., 1221 Barnebey-Cheney Co., 1268-1269 Dravo Corp.,1222-1223 Connor Engineering Corp., 1272- Jackson A Church Co., 1224 1273, 1378-1379 Lee Corp.. 1226 Pur Air Div., Barnebey-Cheney National Heater Co., 1226 LiU.| ** -- Arthur A. Olson & Co.. 1227 Pennsylvania Furnace A Iron Co..' 1199 i Ray Oil Burner Co., 1510-1511 Rheem Mfg. Co., 1202-1203 1 Servel, Inc., 1204-1205 .< Surface Combustion Corp., 1206-' 1207 Syncromatic Corp., 1211 FORCED-AIR DUCTS and FIT TINGS (See Ducts; Fittings) FURNACES. Suspended Airtemp Div., Chrysler Corp., 1196-- 1197 American Furnace Co., 1216 United States Radiator Corp., 1458-1459 Utility Appliance Corp., 1208-1209 Waterman-Waterbury Co., The, FORCED DRAFT COOLING TOWERS (See Coding Towers, Induced Draft, Mechanical Draft) Acme Industries, Inc., 1300 . Air A Refrigeration Corp., 1171 Binks Mfg. Co., 1290-1291 Fluor Corp., Ltd., The, 1292 Foster Wheeler Corp., 1293 Kennard Corp., 1236 Lflie-Hoffmann Cooling Towers, Inc., 3296 Marley Co., The, 1296 Mario Coil Co., 1314 McQuay, Inc., 1236-1237 J. F. Pritchard A Co., 1297 Refrigeration Economics Co., Inc., 1248 Refrigeration Engineering, Inc., 1316 ^ Santa Fe Tank & Tower Co., 1298 Servel, Inc., 1204-1205 American Radiator A Standard 1212-1213 Sanitary Corp., Sunbeam Air York-Shipley, Inc., 1513 Conditioner Div., 1194-1195 Chicago Steel Furnace Co., 1220 Delta Heating Corp., 1221 GAGES, Altitude Dravo Corp., 1222-1223 Electric Auto-Lite Co., The, Instru Hayes Furnace Mfg. A Supply Co., ment A Gauge Div., 1414 1198 Jas. P. Marsh Corp., 1552-1553 Jackson A Church Co., 1224 Surface Combustion Corp., 1206 1207 GAGES, Compound United States Radiator Corp., 1456 C. A. Dunham Co., 1541-1543 1469 Electric Auto-Lite Co., The, In Utility Appliance Corp., 1208-1209 strument A Gauge Div., 1414 Waterman-Waterbury Co., The, Jas. P. Marsh Corp., 1552-1553 1212--1213 Wesix Electrio Heater Co., 1254 GAGES, Liquid Level . Minneapolis-Honeywell Regulator FURNACES, Wall Co., 1428-1429 Delta Heating Corp., 1221 'Rochester Mfg. Co., Inc., 1437 Rheem MfgTCo., 1202-1203 Yaraall-Waring Co., 1561 United States Radiator Corp., 1458 FUEL BURNING EQUIPMENT, 1459 Automatic (See Burners, Auto Utility Appliance Corp., 1208-1209 matic; Gas Burners; OH Burners; Wesix Electric Heater Co., 1254 Stokers) John Zink Co., 1502-1503 GAGES, Pressure C. A. Dunham Co., 1541-1543 , Electric Auto-lite Co., The Instm-i ment A Gauge Div., 1414 FUEL OIL, Heating, Pumping and Straining Units Coen Co., 1496 S. T. Johnson Co., 1508-1609 Killebrew Engineering Corp., 1518 FURNACES, Warm Air, Heavy Duty Air Devices, Inc., 1261, 1372 Airtherm Mfg. Co., 1229 Aladdin Heating Corp^ 1318 American Founory A Furnace Co., 1214-1216 Jas. P. Marsh Corp., 1552-1553 Mercoid Corp., The, 1427 Minneapolis-Honeywell Regulator^ Co., 1428-1429 Perfex Corporation, 1433 Rochester Mfg. Co., Inc., 1437 Taylor Instrument Cos., 1441 FUME DISPOSAL UNITS (Hoods) Laboratory E. H. Sheldon Equipment Co., 1356-1357 FURNACE CABINETS Atlas Mfg. Co., 1538 FURNACE PIPE AND FIT TINGS L. J. Mueller Co., The, 1200-1201 United States Register Co., 1396-- 1397 FURNACES, Electric E. K. Campbell Co., 1217 Campbell Heating Co., 1218-1219 Chicago Steel Furnace Co., 1220 Dravo Corp., 1222-1223 Hayes Furnace Mfg. A Supply Co., 1198 Jackson A Church Co., 1224 Lee Corp., 1225 L. J. Mueller Furnace Co., 1200-1201 National Heater Co., 1226 Arthur A. Olson A Co., 1227 Ray Oil Burner Co., 1510-1511 Rheem Mfg. Co., 1202-1203 Surface Combustion Corp., 1206 1207 Syncromatic Corp., 1208 United States Radiator Corp., 1458-1459 GAGES, Steam Dole Valve Co., The, 1565 C. A. Dunham Co.. 1541-1543 Electric Auto-Lite Co., The, Instru-... ment A Gauge Div., 1414 ; Hoffman Specialty Mfg. Corp.,' 1544-1547 Jas. P. Marsh Corp., 1552-1553 , Minneapolis-Honeywell Regulator.' Co., 1428-1429 ~ GAGES. Tank Minneapolis-Honeywell Regulatory Co., 1428-1429 Rochester Mfg. Co., Inc., 1437 Electromode Corp., 1253 Wesix Electric Heater Co., 1254 FURNACES, Gas-Fired, Floor American Radiator A Standard Sanitary Corp., Sunbeam Air Conditioner Div., 1194-1195 Dravo Corp., 1222-1223 Jackson A Church Co., 1224 Pennsylvania Furnace A Iron Co., 1199 _ Rheem Mfg. Co., 1202-1203 Surface Combustion Corp., 1206 1207 John Zink Co., 1502-1503 FURNACES, Warm Air, Resi dence Airtemp Div., Chrysler Corp., 1196-1197 Aladdin Heating Corp., 1318 American Foundry A Furnace Co., 1214-1215 American Furnace Co., 1216 American Radiator A Standard Sanitary Corp., Sunbeam Air Conditioner Div., 1194-1195 Campbell Heating Co., 1218-1219 Delta Heating Corp., 1221 Electromode Corp., 1253 General Automatic Products Corp., GAGES, Vacuum Dole Valve Co., The 1565 C. A. Dunham Co., 1541-1543 * Electric Auto-Lite Co., The, Instru-r ment A Gauge Div., 1414 1 Hoffman Specialty Mfg. Corp., 1544-:* 1547 Jas. P. Marsh Corp., 1552-1553 Minneapolis-Honeywell Regulator-; Co., 1428-1429 Moeller Instrument Co., 1431 Perfex Corp., 1433 Rochester Mfg. Co., Inc., 1437 Taylor Instrument Cos., 1441 FURNACES, Oil Burning, Floor Airtherm Mfg. Co., 1229 American Foundry A Furnace Co., 1214-1215 . _ j American Radiator A Standard ft Sanitary Corp., Sunbeam Air p Conditioner Div., 1194-1195 Chicago Steel Furnace Co., 1220 1451 General Electric Co., 1182-1183 Hayes Furnace Mfg. A Supply Co., 1198 _ Hoffman Specialty Mfg. Corp., 1644-1547 Jackson A Church Co., 1224 8. T. Johnson Co., 1508-1509 L. J. Mueller Furnace Co., 1200-1201 GAGES, Vapor ,-n C. A. Dunham Co., 1541-1543 Minneapolis-Honeywell Regulator,; Co., 1428-1429 GAGES, Water Yarnall-Waring Co., 1561 Numerals following Manufacturers' Names refer to pages In the Catalog Data Section to Modem Equipment 1153 SS;.-v ?;AtfSmpURD^S Chrysler Corp., Hart & Cooley Mfg. Co., 1380-1381. HEAT RECLAIMERS Hendrick Mfg. Co., 1388-1383 American District Steam'Co.. Inc., *>"1106-1197 TAmcrici&n Furnace Co., 1216 ^American Radiator A Standard ^'Sanitary Corp., 1444-1445 American Radiator A Standard rf-'Sanitary Corp., Sunbeam Air S'-.Conditioner Div., 1194-1195 JiVBabcock A Wilcox Co., The, 1466 H Cleaver-Brooks Co., 1467, 1495 rCoen Co., 1496 'jCrane Co., 1448-1449 cvciDelta Heating Corp., 1221 ^Gordon A Piatt, 1497 He Hastings Air Conditioning Co., Inc., -H85 ? -L. J. Mueller Furnace Co., 1200-1201 National Radiator Co., The, 1452-- '' 1454 .' .Oir A Sembower, Inc., 1478 Pennsylvania Furnace A Iron Co., 1199 ^'Ray Oil Burner Co., 1510-1511 Independent Register Co., The, 1384 Minneapolis-Honeywell Regulator Co.. 1428-1429 Pyle-National Co-, The, Multivent Div., 1386-1388 _ Register A Grille Mfg. (Jo., Inc., 1389 Standard Stamping A Perforating Co., 1390 Stewart Mfg. Co., Inc., 1391 Titus Mfg. Corp., 1392-1393 Tuttle A Bailey, Ino., 1394-1395 United States ^Register Co., 1458 1459 Waterloo Register Co., Inc., 1399 Young Regulator Co., 1401 HANGERS, Pipe Grinnell Co., Inc., 1232-1233 1402-1403 C. L. Rayfield Co., 1512 HEAT SURFACE Aerofin Corp., 1301-1303 Edwards Engineering Corp., 1304 GAO Mfg. Co., The, 1305 Kritzer Radiant Coils, Inc., 1464 McCord Corp., 1238 McQuay, Inc.. 1236-1237 Modine Mfg. Co., 1240-1241 John J. Nesbitt, Inc., 1244-1245 New York Blower Co., 1341 Niagara Blower Co.; 1186 Rome-Turney Radiator Co., The, 1309 Vulcan Radiator Co., The, 1310 Warren Webster A Co., 1562-1564 Young Radiator Co., 1252 SlC. L. Rayfield Co., 1612 ?>>''Sieinon Mfg. Co., 1500 V.Sonner Burner Co., 1501 r:'Surface Combustion Corp., 1206J 1207 & ^United States Radiator Corp., 1458-1459 Utility Appliance Corp., 1208-1209 Waterman-Waterbury Co., The, 1212-1213 v- Webster Engineering Co., The, 1504 John Zink Co., 1502-1503 GAS FILTERS OSes Filters, Gas) HANGERS, Radiator American Radiator A Standard Sanitary Corp., 1444-1445 Carty A Moore Engineering Co., 1540 . National Radiator Co., The, 1452 1454 United States Radiator Corp., 1458 1459 HEADS, Exhaust V. D. Anderson Co., The, 1534-1535 Muckle Mfg. Co., 1363 HEATERS, Air Aerofin Corp., 1301-1303 Air Devices, Inc., 1261, 1372 Airtherm Mfg. Co., 1229 American Foundry A Furnace Co., 1214-1235 Automatic Gas Equipment Co., 1230 Buffalo Forge Co., 1325 E. K. Campbell Co., 1217 Campbell Heating Co., 1218-1219 Chicago Steel Furnace Co., 1220 Combustion Engineeringr Inc., 1468-1469 Dravo Corp., 1222-1223 Electromode Corp., 1253 GAS SAFETY J Pilots) PILOTS (See HEADS, Sprinkler (Fire Protec Grinnell Co.. Inc., 1232-1233 Lee Corp.. 1225 tion) . McQuay, Inc., 1236-1237 Grinnell Co., Inc., 1232-1233 Modine Mfg. Co., 1240-1241 GAS VENT PIPE or GAS VENTS (See Pips, Gas Vent) GASKETS, Cork {' Armstrong Cork Co., (Industrial . Div.), 1587 Mundet Cork Corp., 1597 GLASS BLOCK ROOFLIGHTS (See Skylights Insulated) . GLASS BLOCKS . . Owens-Illinois Glass Co., 1577 "H1 'Pittsburgh Coming Corp., 1578 *fe;' GLASS, Cellular - Pittsburgh Coming Corp., 1579 1 GOVERNORS, Pump Co., 1425 ' McDonnell A Miller, Inc., 1490-1493 Engineering Co., Inc., 1439 barren Webster A Co., 1562-1564 FILTERS (See Filters, GRIDS, Panel American Brass Co., The, 1256-1257 . REGISTERS AND wSSiM.!s"rAL metal ter#) ^ Louvers, Regis- Air Control Products Inc., 1368-1371 hi Su?r Register Co., The, 1373 i- "tason Co., The, 1176-1177 Wr-Colman Co., 1376, 1411 :;,ule Valve Co., The, 1565 HEAT EXCHANGERS Acme Industries, Inc., 1300 Aerco Corp., 1515 . Aerofin Corp., 1301-1303 American District Steam Co., Inc., 1402-1403 Bell A Goesett Co., 1516-1517 Binks Mfg. Co., 1290-1291 Edwards Engineering Corp., 1304 Farrar A Trefts, Ino., 1473 Fluor Corp., Ltd., The, 1292 Hayes Furnace Mfg. A Supply Co., 1198 International Boiler Works Co., The, 1476 Kewanee-Ross Corp., 1479-1483 Killebrew Engineering Corp., 1518 Marley Co., The, 1296 Mario Coil Co., 1314 McCord Corp., 1238 McQuay, Inc., 1236-1237 Modine Mfg. Co., 1240-1241 Moore Dry Kiln Co., 1306 National Radiator Co., The, 1452 1454 John J. Nesbitt, Inc., 1244-1245 Niagara Blower Co., 1186 Patterson-Kelley Co., Inc., The, 1307 J. F. Pritchard A Co., 1297 Refrigeration Economics Co., Inc., 1248 Rome-Turney Radiator Co., The, 1309 Taco Heaters. Inc., 1519 H. A. Thrush A Co., 1520-1521 Trane Co., The, 1246-1247 United States Radiator Corp., 1458 1459 Western Blower Co., 1352 Westinghouse Electric Corp., Sturtevant Div., 1353 Worthington Corp., 1192 York Corp., 1193 Young Radiator Co., 1252 L. J. Mueller Furnace Co., 1200-1201 National Heater Co., 1226 National Radiator Co., The, 3452 1454 Herman Nelson Div., American Air Filter Co., Inc., 1242-1243 John J. Nesbitt, Ine., 1244-1245 Arthur A. Olson A Co., 1227 Surface Combustion Corp., 1206 1207 Syncromatic Corp., 1211 Thermobloc Div., Prat-Daniel Corp., 1228 Trane Co., The, 1246-1247 United States Radiator Corp., 1458 1459 Westinghouse Electric Corp., Stur- tevant Div., 1353 Edwin L. Wiegand Co., 1255 L. J. Wing Mfg. Co., 1249-1251 Young Radiator Co., 1252 John Zink Co., 1502-1503 . HEATERS, Automatic Water, Domestic Hot Airtemp Div., Chrysler Corp., 1196-1197 American Radiator A Standard Sanitary Corp., 1444-1445 Bryan Steam Corp7 1447 Combustion Engineering, Inc., (Chattanooga Div.), 1468-1469 Crane Co., 1448-1449 Dewey-Shepard Boiler Co., 1471 Edwards Engineering Corp., 1304 Frigidaire Div., General' Motors Corp., 1184 S. T. Johnson Co., 1508-1509 Ray Oil Burner Co., 1510-1511 Rheem Mfg. Co., 1202-1203 Rite Engineering A Mfg. Corp., 1455 United States Radiator Corp., 1353 Wesix Electric Heater Co.. 1254 Edwin L. Wiegand Co., 1255 Please mention THE GUIDE 1954 when writing to Advertisers 1154 1954 Gui HEATERS, Blast HEATERS, Gas HEATERS.Storage Aerofin Corp., 1301-1303 Airtemp Div., Chrysler Corp., 1196-- American District Steam Co., Airtherm Mfg. Co., 1229 1197 1402-1403 Bayley Blower Co., 1321 Airtherm Mfg. Co., 1229 Fitsgibbons Boiler Co., Inc., j Carrier Corp., 117S-1179 American Foundry A Furnace Co., 1475 Drayer-Hanson, Inc., 1181 1214-1215 _ Kewanee-Ross Corp., 1479-1483 Electromode Corp., 1253 Automatic Gas Equipment Co., Killebrew Engineering Corp., 15 G & O Mfg. Co., The, 1305 1230 National Radiator Co., The, 1 Hastings Air Conditioning Co., Inc., E. K. Campbell Co., 1217 1454 1185 Campbell Heating Co., 1218-1219 Patterson-Kelley Co., Inc., McCord Corp-, 1238 Cyclotherm Div., U. S. Radiator 1307 MoQuay, Inc., 1236-1237 Corp., 1470 - Modine Mfg. Co., 1240-1241 Dravo Corp., 1222-1223 Moore Dry Kiln Co.. 1306 Hayes Furnace Mfg. A Supply Co., HEATERS, Tank D. J. Murray Mfg. Co.. 1239 1198 Aerco Corp., 1515 John J. Nesbitt, Inc., 1244-1245 Lee Corp., 1225 Bell A Gossett Co.. 1516-1517 Niagara Blower Co.. 1186 L. J. Mueller Furnace Co., 1200-1201 Patterson-Kelley Co., Inc., Rome-Turney Radiator Co., The, National Heater Co., 1228 1307 1309 Arthur A. Olson A Co., 1227 Spencer Heater, Lycoming Div Trane Co.. The, 1246-1247 Rheem Mfg. Co., 1202-1203 Avco Mfg. Corp., 1460-1461 United States Air Conditioning United States Radiator Corp., Taco Heaters, Inc., 1519 Corp.. 1190 . ,, 1458-1459 Wesiz Electrio Heater Co., 1254 Westinghouse Electric Corp., Stur- Utility Appliance Corp., 1206-1209 Edwin L. Wiegand Co., 1255 tevant Div., 1353 John Zink Co., 1502-1503 Edwin L. Wiegand Co., 1255 Young Radiator Co., 1252 HEATERS. Unit HEATERS, Hot Water Service Airtherm Mfg. Co., 1229 Aeroo Corp., 1515 American Blower Corp., 127&-1 HEATERS, Cabinet C. A. Dunham Co., 1541-1543 Electromode Corp., 1253 Modine Mfg. Co., 1240-1241 John J. Nesbitt, Inc., 1244-1245 Trane Co., The, 1246-1247 Wesiz Electric Heater Co., 1254 Young Radiator Co., 1252 Air Devices, Inc., 1261, 1372 Airtemp Div., Chrysler Corp., 1106 1197 Aldrich Co., 1443 American District Steam Co., Inc., 1402-1403 Bell A Gossett Co., 1516-1517 Bryan 8team Corp., 1447 Burnham Corp., 1450 Automatic Gas Equipment9 1230 Bishop A Baboock Mfg. Co.. V (Massachusetts Blower Div.), 1 Brown Products Co., 1446 Buffalo Forge Co., 1325 Burnham Corp., 1450 Campbell Heating Co., 1218-L Carrier Corp., 1178-1179 Crane Co., 1448-1449 Chicago Steel Furnace Co., 1220 Cyclotherm Div., U. S. Radiator Clarage Fan Co., 1180, 1329 HEATERS, Convection (See Base- Corp., 1470 Crane Co., 1448-1449 hoard Heating, Convection Heaters) Dewey-Shepard Boiler Co., 1471 Delta Heating Corp., 1221 Dutton Boilers, Div. H&pman- Dravo Corp., 1222-1223 Dutton Co., 1472 C. A. Dunham Co., 1541-1543 HEATERS. Duct Type Automatic Gas Equipment Co., 1230 Carrier Corp., 1178--1179 _ Hastings Air Conditioning Co., Inc., 1185 Hayes Furnace Mfg. A Supply Co., 1198 _ Surface Combustion Corp., 1206 1207 Edwin L. Wiegand Co., 1255 Fitsgibbons Boiler Co., Inc., 1474-- 1475 S. T. Johnson Co., 1508-1509 Johnston Bros., Inc., 1477 Kewanee-Ross Corp., 1479-1483 L. J. Mueller Furnace Co., 1200-1201 National Radiator Co., The, 1452 1454 Patterson-Kelley Co., Inc., The, 1307 Rheem Mfg. Co., 1202-1203 Rite Engineering A Mfg. Corp., Electromode Corp., 1253 Fedders-Quigan Corp., 1231 Gordon A Piatt, 1497 Grinnell Co., Inc., 1232-1233 Hartzell Propeller Fan Co., Div.' Castle Hills Corp., 1333 Hastings Air Conditioning Inc., 1185 Hayes Furnace Mfg. A Supply 1198 Dg Electric Ventilating Co., 1335 HEATERS, Electric Electromode Corp., 1253 Wesiz Electric Heater Co., 1254 Edwin L. Wiegand Co., 1255 1455 H. B. Smith Co., Inc., The, 1462 Spencer Heater, Lycoming Div., Avco Mfg. Com. 1460-1461 Titusville Iron Works Co., The, (Div. of Struthers-Wells Corp.), Jackson A Church Co., 1224 Kennard Corp., 1235 Lee Corp., 1225 McCord Corp-. 1238 McQuay, Inc., 1236-1237 Modine Mfg. Co., 1240-1241 1484-1485 Muckle Mfg. Co., 1363 United States Radiator Corp., 1458 L. J. Mueller Fura&oe Co., 1200- HEATERS. Feed Water 1459 American District Steam Co., Inc., Vapor Heating Corp., 1487 1402-1403 Weil-McLain Co., 1463 D. J. Murray Mfg. Co., 1239 National Heater Co., 1226 National Radiator Co., The, 1 Bell A Gossett Co., 1516-1517 1454 Foster Wheeler Corp., 1293 Kewanee-Ross Corp., 1479-1483 Patterson-Kelley Co., Inc., The, 1307 Warren Webster A Co., 1562-1564 Worthington Corp., 1192 HEATERS, Fuel Oil American District Steam Co., Inc., 1402-1403 Bell A Gossett Co., 1516-1517 Brown Products Co., 1446 HEATERS, Indirect Aeroo Corp., 1515 Aerofin Corp., 1301-1303 American District Steam Co., Inc., 1402-1403 Bell A Gossett Co., 1516-1517 Campbell Heating Co., 1218-1219 Killebrew Engineering Corp., 1518 Patterson-Kelley Co., Inc., The, 1307 H. A. Thrush A Co.. 1520-1521 York-Shipley, Inc., 1513 Herman Nelson Div., Ameri Air Filter Co., Ino., 1242-1243 John J. Nesbitt, Inc., 1244-1245 New York Blower Co., 1341 Niagara Blower Co., 1186 Arthur A. Olson A Co., 1227 Refrigeration Economics Co., In 1248 Rheem Mfg. Co., 1202-1203 Rittling Corp., The, 1308 Rome-Turney Radiator Co., The, 1309 Sheldons Engineering Ltd.. 1346 Cyclotherm Corp., 1470 Surface Combustion Corp., 120 Dravo Corp., 1222-1223 Kewanee-Ross Corp., 1479-1483 HEATERS, Space, Direct-Fired 1207 .. Automatic Gas Equipment Co., Thermobloc Div., Prat-Darnel National Heater Co., 1226 1230 Corp.. 1228 ' Arthur A. Olson A Co., 1227 Campbell Heating Co., 1218-1219 Patterson-Kelley Co., Inc., The, Chicago Steel Furnace Co., 1220 Trane Co., The, 1246-1247 . United States Air Conditioning 1307 Taco Heaters, Inc., 1519 Dravo Corp., 1222-1223 National Heater Co., 1226 Corp., 1190 United States Radiator Corp., 1458 H. A. Thrush A Co., 1520-1521 Arthur A. Olson A Co., 1227 1459 _ Titusville Iron Works Co., The, Thermobloc Div., Prat-Daniel Utility Appliance Corp., 1208-1209 (Div. of Strutheis-Wells Corp.), Corp., 1228 Warren Webster A Co., 1562-1564 1484-1485 John Zink Co.. 1502-1503 Western Blower Co., 1352 . Numerals following Manufacturers* Names refer to pages in the Catalog Data Section 1155 Titusville Iron Works Co., The, (Div. of Struthezs-Wells Corp.), 1484-1485 Trane Co., The, 1246-1247 United States Radiator Corp.. 1458-1459 Vapor Heating Corp., 1487 Waterman-Waterbury Co., The, 1212-1213 Weil-McL&in Co., 1463 York-Shipley, Inc., 1513 HEATERS. Unit, Gas Fired .Airtherm Mfg. Co., 1229 American Blower Corp., 1272-1273 American Foundry A Furnace Co., 1214-1215 American Furnace Co., 1216 . Automatic Gas Equipment Co., 1230 Cambell Heating Co., 1218-1219 Dravo Corp., 1222-1223 C. A. Dunham Co., 1541-1543 Feddere-Quigan Corn.. 1231 Hastings Air Conditioning Co., Inc., 1185 Hayes Furnace Mfg. A Supply Co., 1198 Hg Electric Ventilating Co., 1234, 1335 Lee Corp., 1225 Modine Mfg. Co., 1240-1241 L. J. Mueller Furnace Co., 1200-1201 National Heater Co., 1226 National Radiator Co., The, 1452 1454 Herman Nelson Div., American Air Filter Co., Inc., 1242-1243 John J. Nesbitt, Inc., 1244-1245 Arthur A. Olson A Co., 1227 Rheem Mfg. Co.. 1202-1203 Sonner-Bumer Co., The, 1501 Surface Combustion Corp., 1206 1207 Thermobloc Div., Prat-Daniel Corp., 1228 Trane Co., The, 1246-1247 United States Air Conditioning Corp., 1190 United States Radiator Corp., 1458- i459 Utility Appliance Corp., 1208-1209 Warren Webster A Co., 1562-1564 Westinghouse Electric Corp., Air Conditioning Div., 1191 L. J. Wing Mfg. Co., 1249-1251 Airtherm Mfg. Co.* 1229 Amenram Foundry A Furnace Co. Campbell Heating Co., 1218-1219 Chicago Steel Furnace Co., 1220 Delta Heating Corp., 1221 Dravo Corp., 1222-1223 Lee Corp 1225 National Heater Co., 1226 Arthur A. Olson A Co., 1227 ihermobloc Div., Prat-Danie Corp., 1228 HEATERS, Unit. Turbine L. J. Wing Mfg. Co., 1249-1251 HEATING SYSTEMS, Air Hes Duty Airtherm Mfg. Co., 1229 mM2i5Foundry 4 Furnace < Campbell Co., 1217 Campbell Heating Co., 1218-1 Ckcago 8teel Furnace Co., 1220 Liravo Corp., 1222-1223 American Foundry A Furnace'Co., 1214-1215 American Radiator A Standard Sanitary Corp., Sunbeam Air Conditioner Div., 1194-1195 Burnham Corp., 1450 Electromode Corp., 1253 General Automatic Products Corp., 1451 General Electric Co., 1182-1183 Hayes Furnace Mfg. A Supply Co., 1198 Jackson A Church Co., 1224 Kritser Radiant Coils, Inc., 1464 L. J. Mueller Furnace Co., 1200-1201 Pennsylvania Furnace A Iron Co., 1199 Servel, Inc., 1204-1205 . Surface Combustion Corp., 1206 1207 Syncromatic Corp., 1211 Trane Co., The, 1246-1247 United States Radiator Corp., 1458-1459 Waterman-Waterbury Co., The, 1212-1213 York-Shipley, Inc., 1513 John Zink Co., 1502-1503 HEATING SYSTEMS. Auto matic Airtemp Div., Chrysler Corp., 1196 1197 Airtherm Mfg. Co., 1229 American Foundry A Furnace Co., 1214-1215 American Radiator A Standard Sanitary Corp., 1444-1445 American Radiator A Standard Sanitary Corp., Sunbeam Air Conditioner Div., 1194-1195 E. K. Campbell Co., 1217 Campbell Heating Co., 1218-1219 Chicago Steel Furnace Co., 1220 Crane Co., 1448-1449 Delta Heating Corp., 1221 Dravo Corp., 1222-1223 C. A. Dunham Co., 1541-1543 Electromode Corp., 1253 General Automatic Products Carp., 1451 General Electric Co., 1182-1183 Hayes Furnace Mfg. A Supply Co., 1198 Jackson A Church Co., 1224 S. T. Johnson Co., 1508-1509 Kewanee-Ross Corp., 1479-1483 Lee Corp., 1225 L. J. Mueller Furnace Co., 1200-1201 National Heater Co., 1226 National Radiator Co., The, 1452 1454 Arthur A. Olson A Co., 1227 Pacific Steel Boiler Div., U. S. Radiator Corp., 1456-1457 Pennsylvania Furnace A Iron Co., 1199 Ray Oil Burner Co., 1510-1511 C. L. Rayfield Co., 1512 Rheem Mfg. Co., 1202-1203 Sarco Co., Inc., 1558-1559 Sarcotherm Controls, Inc., 1557 Surface Combustion Corp., 1206 1207 HEATING SYSTEMS, Goal-fired American Foundry A Furnace Co., 1214-1215 American Radiator A Standard Sanitary Corp., 1444-1445 American Radiator A Standard Sanitary Corp., Sunbeam Air Conditioner Div., 1194-1195 E. EL Campbell Co., 1217 Campbell Heating Co., 1218-1219 Crane Co., 1448-1449 Fitsgibbons Boiler Co., Inc., 1474 1475 Kewanee-Ross Corp., 1479-1483 Lee Corp., 1225 L. J. Mueller Furnace Co., 1200-1201 National Heater Co., 1226 National Radiator Co., The, 1452 1454 Arthur A. Olson A Co., 1227 Syncromatic Corp., 1211 United States Radiator Corp., 1458 1459 Waterman-Waterbury Co., The, 1212-1213 HEATING SYSTEMS. Electric Electromode Corp., 1253 Wesiz Electric Heater Co., 1254 HEATING SYSTEMS. Furnace Airtemp Div., Chrysler Corp., 1196 1197 Airtherm Mfg. Co., 1229 American Foundry A Furnace Co., 1214-1215 American Furnace Co., 1216. American Radiator A Standard Sanitary Corp., Sunbeam Air Conditioner Div.. 1194-1195 Automatic Gas Equipment Co., 1230 E. K. Campbell Co., 1217 Campbell Heating do., 1218-1219 Crane Co., 1448-1449 Dravo Corp., 1222-1223 General Electric Co., 1182-1183 Hayes Furnace Mfg. A Supply Co., 1198 Jackson A Church Co., 1224 S. T. Johnson Co., 1508-1509 Lee Corp., 1225 L. J. Mueller Furnace Co., 1200-1201 National Heater Co., 1226 Arthur A. Olson A Co., 1227 Ray Oil Burner Co., 1510-1511 Rheem Mfg. Co., 1202-1203 Syncromatic Corp., 1211 United States Radiator Corp., 1458 1459 Waterman-Waterbury Co., The, 1212-1213 HEATING SYSTEMS, Gas-fired Airtemp Div., Chrysler Corp., 1196 1197 Airtherm Mfg. Co., 1229 American Foundry A Furnace Co., 1214-1215 American Furnace Co., 1216 American Radiator A Standard Sanitary Corp., 1444-1445 American Radiator A Standard Sanitary Corp., Sunbeam Air Conditioner Div., 1194-1195 Please mention THE GUIDE 1954 when writing to Advertisers Automatic Gas Equipment Co., 1230 Bryan Steam Corp-, 1447 E. K. Campbell Co., 1217 Campbell Heating Co., 1218-1219 Chicago Steel Furnace Co., 1220 HEATING SYSTEMS, Oil Fired Crane Co., 1448-1448 Airtemp Dv., Chrysler Corp., Dewey-Shepard Boiler Co., 1471 1198-1197 ~ HEATING. SYSTEMS. Vacuum Dravo Corp., 1222-1223 - Airtherm Mfg. Co., 1229 Airtemp Div., Chrysler Corp., 119CP' Fitzgibbons Boiler Co., Inc., 1474 American Foundry A Furnace Co. 1197 --c 1475 1214-1215 American Radiator A Standard General Electric Co., 1182-1183 American Furnace Co., 1216 Sanitary Corp.. 1444-1445 ~ . Hayes Furnace Mfg. A Supply Co., American Radiator A Standard Barnes A Jones, Inc., 1539 1198 Sanitary Corp., 1444-1445 C. A. Dunham Co., 1541-1543 Jackson A Church Co., 1224 Brown Products Go., 1446 General Electric Co., 1182-1183 Kewanee-Ross Corp., 1479-1483 Bryan Steam Corp., 1447 Hoffman Specialty Mfg. Corp., 1544-? Lee Ccop., 1225 E. K. Campbell Co.. 1217 1547 f L. J. Mueller Furnace Co., 1200-1201 Campbell Heating Co., 1218-1219 Illinois Engineering Co., 1548-1549 National Heater Co., 1226 Crane Co., 1448-1449 Kewanee-Ross Corp., 1479-1483 ' National Radiator Co., The, 1452 Delta Heating Corp., 1221 Jas. P. Marsh Corp., 1552-1553 . 1454 Arthur A. Olson A Co., 1227 Dewey-Shepard Boiler Co., 1471 Dravo Corp., 1222-1223 National Radiator Co., The, 1452-r 1454 * Rheem Mfg. Co., 1202-1203 Fitzgibbons Boiler Co., Inc., 1474-- Pacific Steel Boiler Div., U. S. Radi-' Syncrorustic Corp., 1211 1475 ator Corp-, 1456-1457 " Titusville Iron Works Co., The, General Automatic Products Corp., Sarco Co., Inc., 1558-1559 (Div. of Struthers-Wells Corp.), 1451 Warren Webster A Co., 1562-1564 1484-1485 General Electric Co., 1182-1183 United States Air Conditioning Jackson A Church Co., 1224 Corp., 1190 8. T. Johnson Co., 1508-1509 HEATING SYSTEMS, Vapor United States Radiator Corp., 1458 Kewanee-Ross Corp., 1479-1483 Airtemp Div., Chrysler Corp.? 1459 Lee Corp., 1225 1196-1197 Utility Appliance Corp., 1208-1209 L. J. Mueller Furnace Co., 1200-1201 American Radiator A Standard Waterman-Waterbury Co., The, National Heater Co., 1226 Sanitary Corp-, 1444-1445' 1212-1213 National Radiator Co., The, 1452-- Barnes A Jones, Inc., 1539 L. J. Wing Mfg. Co., 1249-1251 1454 C. A. Dunham Co., 1541-1543 York-Shipley, Inc., 1513 Arthur A. Olson A Co., 1227 General Electric Co., 1182-1183 Pacific Steel Boiler Div., U. S. Radi Hoffman Specialty Mfg. Corp-^' ator Corp., 1456-1457 1544-1547 HEATING SYSTEMS, High- Ray Oil Burner Co., 1510-1511 Illinois Engineering Co., 1548-1549 temperature Fluid C. L. Rayfield Co., 1512 Kewanee-Ross Corp., 1479-1483 Titusville Iron Works Co., The, Svncromatic Corp., 1211 Jas. P. Marsh Corp., 1552-1553 (Div. of Struthere-Wella Corp.), Waterman-Waterbury Co., The, National Radiator Co., The, H52- 1484-1485 1212-1213 1454 * York-Shipley, Inc., 1513 Pacific Steel Boiler Div., U. S. Radi ator Corp., 1456-1457 ` HEATING SYSTEMS, Hot Water Sarco Co., Inc., 1558-1559 . Air Devices, Inc., 1261, 1372 HEATING SYSTEMS, Steam Titusville Iron Works Co., The, Airtemp Div., Chrysler Corp., 1198 Airtemp Div., Chrysler Corp., (Div. of Struthers-Wells Corp-)* 1197 1198-1197 1484-1485 American Radiator A Standard American Radiator A Standard Trane Co., The, 1246-1247 Sanitary Corp., 1444-1445 Sanitary Corp., 1444-1445 United States Radiator Corp., 1458r Bell A Gossett Co.. 1516-1517 Barnes A Jones, Inc., 1539 1459 Brown Products Co., 1446 Brown Products, Co., 1446 Vapor Heating Corp., 1487 . Bryan Steam Corp., 1447 Bryan Steam Corp., 1447 Warren Webster A Co., 1562-1564 Burnham Corp., 1450 Burnham Corp., 1450 York-Shipley, Inc., 1513 " Cleaver-Brooks Co., 1467, 1495 Cleaver-Brooks Co., 1467, 1495 Crane Co., 1448-1449 Crane Co., 1448-1449 Durant Insulated Pipe Co., 1572 Dewey-Shepard Boiler Co., 1471 HOSE, Flexible Metal 1573 C. A. Dunham Co., 1541-1543 American Brass Co., The, 1255-1257^ Durant International Corp., 1572 Durant Insulated Pipe Co., 1572 Flexonics Corp., Chicago Metal; 1673 1573 Hose Div., 1258 v Fitzgibbons Boiler Co., Inc., 1474-- Durant International Corp., 1572 1475 1573 General Automatic Products Corp., Fitzgibbons Boiler Co., Inc., 1474 HOT WATER HEATING SYS 1451 1475 TEMS (See Heating Systems, Hot- General Electric Co., 1182-1183 General Electric Co., 1182-1183 Water) Hoffman Specialty Mfg. Corp., Hoffman Specialty Mfg. Corp., 1544-1547 1544-1547 S. T. Johnson Co., 1508-1509 Illinois Engineering Co., 1548-1549 HUMIDIFIERS , Kewanee-Ross Corp., 1479-1483 S. T. Johnson Co., 1508-1509 Air A Refrigeration Corp., 1171' Kritzer Radiant Coils, Inc., 1464 Kewanee-Ross Corp., 1479-1483 American Blower Corp., 1272-1276 Jas. P. Marsh Corp., 1552-1553 Kritzer Radiant Coils, Inc., 1464 American Moistening Co., 1174 L. J. Mueller Furnace Co., 1200-1201 Jas. P. Marsh Corp., 1552-1553 American Radiator A Stands National Radiator Co., The, 1452 L. J. Mueller Furnace Co., 1200-1201 Sanitary Corp., Sunbeam Air 1454 National Radiator Co., The, 1452 Conditioner Div., 1194-1195 Pennsylvania Furnace A Iron Co., 1454 Armstrong Machine Works, 1536^ 1199 Pacific Steel Boiler Div., U. S. 1537 ' Refrigeration Engineering, Inc., Radiator Corp., 1456-1457 Bahnson Co., The, 1176-1177 1316 Pennsylvania Furnace A Iron Co., Binks Mfg. Co., 1290-1291 -f Ric-wiL Co., The, 1575 1199 Buensod-Staoey, Inc., 1175 ' Sarco Co., Inc., 1558-1559 Ric-wiL Co., The, 1575 Buffalo Forge Co., 1325 Sarcotherm Controls, Inc., 1557 Sarco Co.. Inc., 1558-1559 Carrier Corp., 1178-1179 Shaw-Perkins Mfg. Co./1465 . Shaw-Perkins Mfg. Co., 1465 Clarage Fan Co., 1180, 1329 H. B. Smith Co., Inc., The, 1462 H. B. Smith Co., Inc., The, 1462 Farr Co., 1278-1277 Taco Heaters, Inc., 1519 Titusville Iron Works Co., The Maid-O'-Mist, Inc., 1550-1551 Trane Co., The, 1248-1247 (Div. of Struthere-Wells Corp.), Jas. P. Marsh Corp., 1552-1553 H. A. Thrush A Co., 1528-1521 t 1484-1485 Mario Coil Co., 1314 . United States Air Conditioning Trane Co., The, 1246-1247 McDonnell * Miller, Inc., 1490-1493, Corp., 1190 United States Air Conditioning L. J. Mueller Furnace Co., 1200-120, United States Radiator Corp., Corp., 1190 Niagara Blower Co., 1186 ' 1458-1459 United States Radiator Corp., 1458 Parka-Cramer Co., 1188-1189 Vapor Heating Corp., 1487 1459 H. J. Somers, Inc., 1282-1283 Numerals following Manufacturers' Names refer to pages in the Catalog Data Section vsfeisv dSrane Co., The, 1246-1247 Johnson Service Co., 1422-1423 Celotex Carp., The, 1588 Vikmg Air Conditioning Corp., 1351 ^HUMIDIFIERS, Central Plant . 'aAt Refrigeration Corp., 1171 -American Moistening Co., 1174 -'Armstrong Machine Works, 1538- ^*1537 Bahnson Co., The, 1178-1177 - %Barber-Colman Co., 1376, 1411 ^uBayley Blower Co., 1321 \-jBuensod-Stacey, Inc., 1175 ^Buffalo Forge Co., 1325 "'Carrier Corp-, 1178-1179 ^ Clarage Fan Co., 1180, 1329 >*Farr Co., 1276-1277 ^Johnson Service Co., 1422-1423 .^Marlo Coil Co.. 1314 ->Jas. P. Marsh Corp., 1552-1553 ^McDonnell A Miller. Inc., 1490-1493 ^.'Niagara Blower Co., 1186 '^Parks-Cramer Co., 1188-1189 '"Powers Regulator Co., The, 1434-- Minneapolis-Honeywell Regulator Co.. 1428-1"429 Moeller Instrument Co., 1431 Parks-Cramer Co., 1188-1189 Powers Regulator Oo., 1434-1436 Taylor Instrument Cos., 1441 ____ _____ . HYGROMETERS (See Humidity Recorders and Indicators) American Moistening Co., 1174 Minneapolis-Honeywell Regulator Co., 1428-1429 Moeller Instrument Co., 1431 Parks-Cramer Co., 1188-1189 Taylor Instrument Cos., 1441 IGNITION. Oil Burner See Transformers) INDUCED DRAFT COOLING Dow Chemical Co., The, 1589 Glass Fibere Inc., 1582 Gustin-Bacon Mfg. Co., 1583 Infra Insulation, Inc., 1602 Insul-Mastic Corn of Azs"*"" t1 Insulite, 159(M591 ** ~ Johns-Manville, 1592-1593 Kimberly-Clark Corp., 1594-1595 Luowcnkupovri,t M iMllisn,, Ixnucu.,, 1U579V6 Munaet Cork Corp., 1597 Owens-Coming Fiberglas Corn.. 1281, 1585 Pacific Lumber Co., The, 1598 Pittsburgh Corning Corp., 1579 H. W. Porter A Co., Inc., 1574 Reflectal Corp., 1604 Reid Hayden, Inc., 1574 Silvercote Products, Inc., 1605 Sprayo-Flake Insulation Co., 1586 United States Gypsum Co., 1599 Wood Conversion Co., 1600 Z-Crete Div., Zonolite Co., 1576 *y'i"1436 Trane Co., The, 1246-1247 ,.>>Westinghouse Electric Corp., Sturf;^,.tevant Div., 1287 -V. W-i' HUMIDIFIERS, Convector Maid-O'-Mist, Inc., 1550-1551 .'vV. HUMIDIFIERS, Industrial American Moistening Cv,ov., 1174 a, Armstrong Machine Works, 15361537 T-H Bahnson Co., The, 1176-1177 Binks Mfg. Co., 1290-1291 -Maid-O'-Mist, Inc., 1550-1551 . Parks-Cramer Co., 1188-1189 v TOWERS (See Cooling Towers, Forced Draft, Mechanical Draft) INSULATION, Calcium Silicate Acme Industries, Inc., 1300 Johns-Manville, 1592-1593 Baltimore Aircoil Co., Inc., 1289 Owens-Corning Fiberglas Corn., Binks Mfg. Co., 1290-1291 Kaylo, 1585 Fluor Corp., Ltd., The, 1292 Foster Wheeler Corp., 1293 Kennard Corp*, 1235 INSULATION, Cellular Glass Lilie-Hoffmann Cooling Towers,. Armstrong Cork Co., 1587 Inc., 1295 Pittsburgh Corning Corp.,1579 Marley Co., The, 1296 Mario Coil Co., 1314 Refrigeration Economics Co., Inc., INSULATION, Cork 1248 Armstrong Cork Co., 1587 Santa Fe Tank A Tower Co., 1298 Insul-Mastic Corp. of America, 1584 C. H. Wheeler Mfg. Co., 1533 Mundet Cork Corp., 1597 H. W. Porter A Co., Inc., 1574 Reid Hayden, Inc., 1574 INSERTS, Concrete Carty A Moore Engineering Co., _&3f; HUMIDIFIERS, Spray 1540 INSULATION, Cotton American Moistening Co., 1174 Lockport Mills, Inc., 1596 Bahnson Co., The, 1176-1177 Binks Mfg. Co., 1290-1291 INSTRUMENTS. Indicating, Maid-O'-Mist, Inc., 1550-1551 Controlling and Recording INSULATION, Ducts, Ventilat Barber-Colman Co., 1376, 1411 ing, Air Conditioning HUMIDIFIERS. Unit Combustion Control Corp., 1413 Armstrong Cwo.rok. Co., 1587 Electric Auto-Lite Co.. The, In- Philip Carey Mfg. Co., The, 1580- '^.. American Moistening Co., 1174 strument A Gauge Div., 1414 1581 Armstrong Machine Works. 1536- Illinois Testing Laboratories, Inc., Celotex Com., The, 1588 1537 1424 Dow Chemical Co., The, 1589 *- - Bahnson Co., The, 1176-1177 - Buffalo Forge Co., 1325 Johnson Service Co., 1422-1423 Jas. P. Marsh Corp., 1552-1553 Gla--ss rF'i:bi-e--r-s- TI-n-c., 1582 Gustin-Bacon Mfg. Co., 1583 >/ fan-Co.. 1276-1277 -J:; Mario Coil Co., 1314 *. S:J* Murr*y Mfg. Co., 1239 Minneapolis-Honeywell Regulator Infra Insulation, Inc., 1602 Co., 1428-1429 Insul-Mastio Corp. of America, Moeller Instrument Co., 1431 1584 ; Niagara Blower Co., 1186 Moore Dry Kiln Co., 1306 Johns-Manville, 1592-1593 % Parks-Cramer Co., 1188-1189 Perfex Corp., 1433 Kimberly-Clark Corp., 1594-1595 ;* J- Somers. Inc., 1282-1283 Powers Regulator Co., The, 1434 Lockport Mills, Ino., 1596 "ane Co., The, 1246-1247 1436 Munaet Cork Corp.. 1597 Rochester Mfg. Co., 1437 Owens-Coming Fiberglas Corp., Taylor Instrument Cos., 1441 ^ tempera TURE CONTROL Kaylo, 1585 Pittsburgh Coming Corp., 1579 Reflectal Corp., 1604 ^American Moistening Co., 1174 INSULATION, Acoustical (See Sprayo-Flake Insulation Co., 1588 ` 1537 Machine Works, 1536- e>,Baluon Co., The, 1176-1177 Insulation, Sound Deadening) United States Gypsum Co., 1599 Wood Conversion Co., 1600 *"arber-Colman Co., 1376. 1411 I' Bnenaod-Stacey, Inc.. 1175 V ,A- Dunham Co., 1541-1543 - Johnson Service Co., 1422-1423 4- ;Sa,1 0011 Co.. 1314 A; "ereoid Corp^ The, 1427 O^UlSS1'^ Regulator Parks-Cramer Co., 1188-1189 oT. p61111 Controls, Inc., 1432 INSULATION, Aluminum Infra Insulation, Inc., 1602 Reflectal Corp., 1604 Silvercote Products, Inc., 1605 INSULATION, Anchors and Ad hesives (See Anchors, Adhesives) INSULATION, Felt Glass Fibers Inc., 1582 Johns-Manville, 1592-1593 Kimberly-Clark Corp., 1594-1595 Lockport Mills, Inc., 1596 Owens-Coming Fiberglas Com.. 1585 Wood Conversion Co., 1600 rt- .v; ^era Regulator Co., 1434-1436 i^y-Power Co., The, 1315 . i^ywr Instrument Cos., 1441 A* "bite-Rodgers Electric Co., 1442 f Hm2u5Tog|CORDERS and Mobtening Co., 1174 -'i"arberr--CCoollmman Co., 1S37R6,* m141t1 INSULATION, Asbestos (See Cov ering, Pips) INSULATION, Building American Flange A Mfg. Co., Inc., 1601 Armstrong Cork Co., 1587 Philip Carey Mfg. Co., The, 1580 1581 INSULATION, Fiber Celotex Corp., The, 1588 Glass Fibers Inc., 1582 Gustin-Bacon Mfg. Co., 1583 Insulite. 1590-1591 Kimberly-Clark Corp., 1594-1595 . Lockport Mills, Inc.. 1596 Owens-Coming Fiberglas Corn., 1585 Please mention THE GUIDE 1954 when writing to Advertisers 1158 1954 Guide* Pacific Lumber Co., The, 1598 Pacific Lumber Co., The, 1598 LIQUID LEVEL GAGES (See Sprayo-Flake Insulation Co., 1586 Sprayo-Flake Insulation Co., 1586 Gages, Liquid Level) * United States Gypsum Co., 1599 United States Gypsum Co., 1599 Wood Conversion Co., 1600 Wood Conversion Co., 1600 Zonolite Co., 1576 LOUVERS (Also see Grilles, Regis ters) '.t. INSULATION. Low Tempera ture ... Dow Chemical Corp., The, 1589 INSULATION, Magnesia INSULATION. Steel American'Flange A Mfg. Co., Inc., 1601 . Sprayo-Flake Insulation Co., 1586 American Foundry A Furnace Co.,'? 1214-1215 Auer Register Co., The, 1373 Bahnson Co., The. 1176-1177 Barber-Column Co., 1376, 1411 Dole Valve Co., The, 1565 Philip Carey Mfg. Co., The, 1580 Duro-Dyne Corp., 1400 ^ 1581 Johns-Manville, 1593-1593 Mundet Cork Corp., 1597 Hart A Cooley Mfg. Co., 1380-1381^ INSULATION, Structural Hendrick Mfg, Co.. 1382-1383 * American Flange A Mfg. Co., Inc., Independent Register Co., The, 1384.^ 1601 . Minneapolis-Honeywell Regulator- INSULATION, Metal American Flange A Mfg. Co., Inc., 1601 . Infra Insulation, Inc., 1602 Reflectal Corp., 1604 Silvercote Products, Inc., 1605 Sprayo-Flake Insulation Co., 1586 INSULATION, Mineral American Gilsonite Co. 1571 Owens-Coming Fiberglas Corp., Armstrong Cork Co. (Building Ma terials Div.), 1587 Celotex Corp., The, 1588 Insul-Mastic Corp. of America, 1584 Insulite, 1590-1591 Johns-Manville, 1592-1593 Owens-Coming Fiberglas Corp., Kaylo, 1585 Pittsburgh Corning Corp., 1579 United States Gypsum Co., 1599 Wood Conversion Co., 1600 Zonolite Co., 1576 Co.. 1428-1429 Pyle-National Co., The, (Multi- Vent Div.), 1386-1388 y Register A Grille Mfg. Co., Inc.,.; 1389 Standard Stamping A Perforating; Co-, 1390 " Stewart Mfg. Co.. Inc., 1391 Swartwout Co., The, 1365 Titus Mfg. Corp., 1392-1393 . United States Register Co., 1396-. 1397 Waterloo Register Co., Inc., 1399 Kaylo, 1585 _ L. J. Wing Mfg. Co., 1249-1251 Sprayo-Flake Insulation Co., 1586 INSULATION, Underground United States Gypsum Co., 1599 Z-Crete Div., Zonolite Co., 1576 . Steam Pipe , American Gibsonite Co., 1571 MECHANICAL DRAFT APPA Durant Insulated Pipe Co., 1572 RATUS (See Blowers, Forced 1573 Draft, Exhausters Laboratory Fume; INSULATION, Mineral Wool Durant International Corp., 1572 Laboratory Ventilation) (See Insulation, Building) 1573 American Blower Corp., 1272-1273 Johns-Manville, 1592-1593 DeBothezat Fans Div., American Owens-Coming Fiberglas Corp., Machine A Metals, Inc., 1330 INSULATION, Pipes and Sur Kaylo, 1585 General Blower Co., 1332 faces (See Catering, Pipe and Pittsburgh Coming Corp., 1579 . Pacific Steel Boiler Div., U. S. Radi Surface) H. W. Porter A Co., Inc., 1574 Reid Hayden, Inc., 1574 ator Corp., 1456-1457 E. H. Sheldon Equipment Co., 1356 Ric-wiL Co., The, 1575 1357 . INSULATION, Plastic ' Dow Chemical Co., The, 1589 Z-Crete Div., Zonolite Co., 1576 Westinghouse Electric Corp., Sturtevant Div., 1353 Sprayo-Flake Insulation Co., 1586 INSULATION. Reflective American Flange A Mfg. Co., Inc., 1601 Celotex Corp., The, 1588 Glass Fibers, Inc., 1582 Infra Insulation, Inc., 1602 Kimberly-Clark Corp., 1594-1595 Lockport Mills, Inc., 1596 Reflectal Corp., 1604 Silvercote Products, Inc., 1605 Sprayo-Flake Insulation Co., 1586 INSULATION, Refractory Armstrong Cork Co., 1587 Philip Carey Mfg. Co., The, 1580 1581 Johns-Manville, 1592-1593 INSULATION, Water April Showers Co., Inc., 1569 MECHANICAL DRAFT COOL ING TOWERS (See Codling Towers, Forced Draft,. Induced Draft) INSULATION. Window Screens sAcme Industries, Inc., 1300 Ingereoll Products Div., Borg- Baltimore Aircoil Co., Inc., 1289 Waraer Corp., 1603 Binks Mfg. Co., 1290-1291 Drayer-Hanson. Inc., 1181 Fluor Corn., Ltd., The, 1292 JOINTS, EXPANSION (See Ex pansion joints) Kennard Corp., 1235 Lilie-Hoffmann Cooling Inc., 1295 Mariey Co., The, 1296 Towers, LABORATORY AND TESTING Laboratory) RESEARCH (See Testing Mario Coil Co., 1314 McQuay, Inc., 1236-1237 J. F. Pritchard A Co., 1297 Refrigeration Economics Co., Inc., 1248 Santa Fe Tank A Tower Co., 1298 LABORATORY VENTILATION C. H. Wheeler Mfg. Co., 1533 (See Exhausters, Laboratory Fume: INSULATION, Sheets, Stainless Steel A merieap Flange A Mfg. Co., 1601 Fume Disposal Units (Hoods) Laboratory) METAL INSULATION (See In sulation, Metal) INSULATION, Sound Deaden ing (See also Fell, Sound Deaden ing) Armstrong Cork Co., 1587 Philip Carey Mfg. Co., The, 1580 1581 Celotex Corp., The, 1588 Glass Fibers Inc., 1582 Gustin-Bacon Mfg. Co., 1583 Insul-Mastic Corp. of America, 1584 Insulite, 1590-1591 Johns-Manville, 1592-1593 Kimberly-Clark Corp., 1594-1595 Lockport Mills, Inc.. 1596 Munaet Cork Corp., 1597 Owens-Coming Fiberglas Corp., 1281, 1585 LIQUID LEVEL CONTROLS Aloo Valve Co., 1410 Barber-Colman Co., 1376, 1411 General Controls, 1418-1419 Johnson Service Co., 1422-1423 Leslie Co., 1425 Jas. P. Marsh Corp., 1522-1523 McDonnell A Miller, Inc., 1490-1493 METERS. Air Anemostat Corp. of America, 1374 1375 _ Illinois Testing Laboratories, Inc., 1424 , Minneapolis-Honeywell Regulator Co.. 1428-1429 Minneapolis-Honeywell Regulator Co.. 1428-1429 Penn Controls. Inc.. 1432 Photoswitch Inc., (Affiliate of Com bustion Control Corp.), 1413 Powers Regulator Co., The, 1434 METERS, Flow Minneapolis-Honeywell Regulator Co., 1428-1429 ' Taylor Instrument Cos., 1441 1436 ' Sarco Co., Inc., 1558-1559 METERS, Steam Spence Engineering Co., Inc., 1439 Minneapolis-Honeywell Regulator Taylor Instrument Cos., 1441 Co., 1428-1429 Numerals following Manufacturers' Names refer to pages in the Catalog Data Section Index to Modem Equipment 1159 'C;* . ^MIXERS, Hot-Cold Water, Fitzgibbons Boiler Co., Ine., 1474- L. J. Mueller Furnace Co., 1200-1201 %liSteam-Water 1475 . ^ _ National Radiator Co., The, 1452 `^American Radiator A Standard General Automatic Products Corp., 1454 Sanitary Corp-, 1444-1445 Vf-Dole Valve Co., 1526 1451 S. T. Johnson Co., 1508-1509 Pacific Steel Boiler Div., U. S. Radiator Corp.. 1456-1457 iFnltbn Sylphon Div., The, Robert- Johnston Bros., Inc., 1477 Ray Oil Burner Co., 1510-1511 ?/;ahaw-Fulton Controls Co., 1416- L. J. Mueller Furnace Co., 1200-1201 C. L. Rayfield Co., 1512 **'1417 ^Powers Regulator Co., 1434-1436 Orr A Sembower, Inc., 1478 Ray Oil Burner Co., 1510^-1511 C. L. Rayfield Co.. 1512 Serve!, Inc., 2204-1205 Surface Combustion Corp., 1206 1207 United States Radiator Corp., Webster Engineering Co., The, 1509 vMIXERS, Steam and Water 1458-1459 . ^Powers Regulator Co., 1434-1436 Webster Engineering Co., The, 1509 OIL BURNING SYSTEMS. In dustrial ^MOTORS, Damper OIL BURNERS, Pressure Atom Coen Co., 1496 >^T-Barber-Colman Co., 1376, 1411 izing Enterprise Engine A Machinery Merooid Corp The, 1427 Airtemp Div., Chrysler Corp., 1196 ^.-Minneapolis-Honeywell Regulator 1197 Co., Burner Div., Sub. of General Metals Corp., 1507 Co., 1428-1429 Aldrich Co., 1443 S. T. Johnson Co., 1508-1509 *.- *Penn Controls, Inc., 1432 American Furnace Co., 1216 Ray Oil Burner Co., 1510-1511 Powers Regulator Co., The, 1434 American Radiator A Standard 1436 Sanitaiy Corp., 1444-1445 Automatic Burner Corp., 1506 OIL TANK GAGES (See Gages. Babcock A Wilcox Co., The, 1466 Tank) MOTORS, Electric Burnham Corp., 1450 Peerless Electric Co.. 1342 Cleaver-Brooks Co., 1467, 1495 Propellair Div., Robbins A Myers, Coen Co., 1466 ORIFICES, Radiator Inc. ,1343 Crane Co., 1448-1449 C. A. Dunham Co., 1541-1543 U. 8. Electrical Motors, Inc., 1354 Enterprise Engine A Machinery Illinois Engineering Co., 1548-1549 Wagner Electric Corp., 1355 Co., Burner Div., Sub. of General Johnson Service Co., 1422-1423 Metals Corp., 1507 Minneapolis-Honeywell Regulator Fitzgibbons Boiler Co., Inc., 1474-- Co.. 1428-1429 . NOISE ELIMINATORS (See Tub 1475 Sarco Co., Inc., 1558-1559 ing, Flexible; Sound Deadeners; General Automatic Products Corp., Sarcotherm Controls, Inc., 1557 . Vibration Absorbers) 1451 Warren Webster A Co. 1562-1564 S. T. Johnson Co., 1508-1509 L. J. Mueller Furnace Co., 1200-1201 NON-FERROUS METAL CON Orr A Sembower. Inc., 1478 ORNAMENTAL GRILLS (See DUIT (See Conduit, Non-ferrous Ray Oil Burner Co., 1510-1511 Deflection Grilles, Grilles, Registers Metal) C. L. Bayfield Co., 1512 and Ornamental Metal Work, Lou Sonner Burner Co., The, 1501 vers, Registers) Syncromatic Corp., 1211 NOZZLES, Air Diffusion, Air United States Radiator Corp., 1458 Washing, Brine Spraying. Hu 1459 PANEL GRIDS (See Grids, Pand) midifying. Oil Burner, Water John Zink Co., 1502-1503 Cooling (See Spray Nozzles) PANEL HEATING NOZZLES, Oil Burner Automatic Burner Corp., 2506 Eddington Metal Specialty Co., 1505 Monarch Mfg. Works, Inc., 1299 OIL BURNERS, Rotary Enterprise Engine A Machinery Co., Burner Div., Sub. oi General Metals Corp., 1507 S. T. Johnson Co., 1508-1509 American Radiator A Standard Sanitary Corp., 1444-1445 Crane Co., 1448-1449 Kritzer Radiant Coils, Inc., 1464 Sarcotherm Controls, Inc., 1557 Johnston Bros., Inc., 1477 Ray Oil Burner Co., 1510-1511 OIL BURNER MOTORS (See C. L. Rayfield Co., 1512 Motors, Electric) ' PANELS, Air Distributing Pyle-National Co., The, (Multi Vent Div.), 1386-1388 OIL BURNER TUBING, Flex ible (See Tubing, Flexible, Me tallic) OIL BURNERS Aldrich Co., 1443 American Radiator A Standard Sanitary Corp., 1444-1445 Automatic Burner Corp., 1506 Bryan Steam Corp., 1447 OIL BURNERS, Steam Atomiz ing Babcock A Wilcox Co., The, 1466 Coen COy, 1496 Webster Engineering Co., The, 1509 John Zink Co., 1502-1503 OIL BURNERS, Vaporizing American Furnace Co., 1216 Automatic Burner Corp., 1506 PERFORATED METALS . Hart A Cooley Mfg. Co., 1380-1381 Hendrick Mfg. Co., 1382-1383 Pyle-National Co., The, (Multi Vent Div.), 1386-1388 Standard Stamping A Perforating Co., 1390 United States Register Co., 1396 1397 Cleaver-Brooks Co., 1467, 1495 PILLOW BLOCKS Coen Co., 1496 OIL BURNERS, Variable Capac Lau Blower Co., The, 1338-1339 Enterprise Engine A Machinery ity Co., Burner Div., Sub. of General Metals Corp., 1507 ay Oil Burner Co., 1510-1511 Enterprise Engine A Machinery Co., Burner Div., Sub. of General Metals Coin., 1507 C. L. Rayfield Co., 1512 PILOTS, Safety General Controls, 1418-1419 Mpwaukee Gas Specialty Co., 1430 Minneapolis-Honeywell Regulator OIL BURNERS, Automatic Aldnch Co.. 1443 ` Airtemp Div., Chrysler Corp., 1196- American Radiator A Standard sanitary Corp., 1444-1445 American Radiator A Standard Sanitary Corp., Sunbeam Air Conditioner Div., 1194-1195 Automatic Burner Corp., 1506 Cleaver-Brooks Co., 1467, 1495 OIL BURNING EQUIPMENT Aldrich Co., 1443 American Radiator A Standard Sanitaiy Corp., 1444-1445 Automatic Burner Corp., 1506 Brown Products Co., 1446 Coen Co., 1496 Enterprise Engine A Machinery Co., Burner Div., Sub. of General Metals Corp., 1507 Co., 1428-1429 Penn Controls, Inc., 1432 Perfex Corp., 1433 White-Rodgers Electric Co., 1442 PIPE ALIGNMENT GUIDES American District Steam Co., 1402-1403 PIPE ANCHORS ,, Enterprise Engine A Machinery General Automatic Producte Corp., American District Steam Co.. Ine., Burner Div., Sub. of General 1451 1402-1403 ;; Metals Corp., 1507 General Electric Co., 1182-1183 GrinneU Co., Ine., 1232-1233. Please mention THE GUIDE 1954 when writing to Advertisers 1160 PIPE BENDING Acme Industries, Inc., 1300 GrinneU Co., Inc., 1232-1233 Parks-Cramer Co., 1188-1189 PIPE, Brass American Brass Co., The, 1256-1257 Revere Copper 4 Brass, Inc., 1259 Wolverine Tube Div. of Calumet 4 Hecla, Inc., 1260 , PIPE CONDUITS (See Conduits, 1 Underground Pipe) PIPE, Copper American Brass Co., The, 1256-1257 Revere Copper 4 Brass, Inc., 1259 Wolverine Tube Div. of Calumet 4 Hecla, Inc., 1260 ' PIPE COVERING (See Covering Pipe) PIPE, Fabricated Dutton Boilere, Div. Hapman- Dutton Co., 1472 Fluor Corp., Ltd., The, 1292 GrinneU Co., Inc., 1232-1233 PIPE FITTINGS (See Fittings, Pipe) PIPE, FURNACES (See Furnace Pipe) PIPE, Gas Vent Metalbestce Div., William Wallace Co., 1498-1499 PLASTER BASE, Fire Retarding Celotex Corp., The, 1588 Johns-Manville, 1592-1593 Zonolite Co., 1576 PLASTER BASE, Insulatlve ' Celotex Corp., The, 1588 Insulite, 1590-1591 Johns-ManviUe, 1592-1593 Wood Conversion Co., 1600 Zonolite Co., 1576 PLASTER BASE, Sound Dead ening Celotex Corp., The. 1588 Insulite, 1590-1591 Wood Conversion Co., 1600 ZonoUte Co., 1576 PLATES, Stainless Steel United States Steel, 1367 PLATES, Steel United States Steel, 1367 PRECIPITATING EQUIPMENT American Air Filter Co., Inc., 1265 1267 Dollinger Corp., 1274-1275 Trion, Inc., 1285 Westinghouse Electric Corp., Stur- tevant Div., 1353 PREHEATERS. Fuel Oil American District Steam Co., Inc., 1402-1403 BeU 4 Gossett Co., 1516-1517 Kewanee-Ross Corp., 1479-1483 Killebrew Engineering Corp., 1518 Taco Heaters, Inc., 1519 H. A. Thrush & Co., 1520-1521 Western Blower Co., 1352 American Society of Refrigerating Engineers, 1606 " Coal-Heat, 1607 Domestic Engineering, 1608 . Heating & Plumbing Equipment News, 1609 ' Heating 4 Ventilating, 1609 Heating, Piping and Air Condition^ ing, 1610 'i Plumbing and Heating Journal! 1611 Sheet Metal Worker, 1611 Snips Magazine, 1612 PUMP CONTROLLERS . McDonneU 4 Miller, Inc., 1490-1493? PUMP MOTORS (See Motors, Electric) PUMPS, Ammonia Worthington Corp., 1192 York Corp., 1193 PUMPS. Boiler Feed Aurora Pump Co., 1522 Buffalo Pumps, Inc., 1523 Chicago Pump Co., 1524-1525 Crane Co., 1448-1449 Decatur Pump Co., 1526 C. A. Dunham Co., 1541-1543 v Dutton Boilers, Div. Hapman- Dutton Co., 1472 1 Hoffman Specialty Mfg. Corp., 1544-1547 5f -Ingereoll-Rand, 1527 x Nash Engineering Co., The, 1528---1, 1529 ; Peerless Pump Div.. Food Ma-. chinery 4 Chemical Corp., 1531tk Skidmore Corp., 1532 7 Spence Engineering Co., Inc., 1439 ( Wheeler-Economy Pumps, Inc., 1533 ' Worthington Corp., 1192 ' PIPE HANGERS (See Hangers, , Pipe) PRESSURE REDUCING VALVES (See Regulators, Pres sure) PIPE HEATING Edwin L. Wiegand Co., 1255 PROCESS HEATING UNITS Air Devices, Inc., 1261, 1372 PIPE, Returns GrinneU Co., Inc., 1232-1233 Niagara Blower Co., 1186 Trane Co., The. 1246-1247 L. J. Wing Mfg. Co., 1249-1251 PUMPS. Brine Aurora Pump Co., 1522 Buffalo Pumps. Inc., 1523 > Chicago Pump Co., 1524-1525 Ingereoll-Rand, 1527 Peerless Pump Div.. Food Ma-/ chinery 4 Chemical Corp., 1531V, Wheeler-Economy Pumps, Inc., 1533Worthington Corp., 1192 PIPE, Spiral Welded Moore Dry Kiln Co., 1306 Taylor Forge 4 Pipe Works, 1408 PIPE, Steel Farrar 4 Trefts, Inc., 1473 GrinneU Co., Inc., 1232-1233 Taylor Forge 4 Pipe Works, 1408 PIPE SUPPORTS. For Under ground Conduits Durant Insulated Pipe Co., 1572-- 1573 Durant International Corp., 1572-- 1573 H. W. Porter 4 Co., Inc., 1574 Reid Hayden, Inc., 1574 Ric-wiL Co., The, 1575 Z-Crete Div., ZonoUte Co., 1576 PIPE, Wood Sante Fe Tank 4 Tower Co., 1298 PITOT TUBES (See Air Measuring and Recording Instruments) PROCESS HEATING UNITS* Fluid Heating and Cooling American District Steam Co., Inc., 1402-1403 Killebrew Engineering Corp., 1518 Arthur A. Olson & Co., 1227 Trane Co., The, 1246-1247 PROPELLER FANS (See Fans, Propeller) PSYCHROMETERS (See Air Measuring, Indicating and Re cording Instruments) American Moistening Co., 1174 Bahnson Co., The, 1176-1177 lUinois Testing Laboratories, Inc., 1424 Johnson Service Co., 1422-1423 Minneapolis-Honeywell Regulator Co., 1428-1429 Moeller Instrument Co., 1431 Parks-Cramer Co., 1188-1189 Powers Regulator Co., 1434-1436 Taylor Instrument Cos., 1441 PUBLICATIONS American Artisan, 1610 PUMPS, Centrifugal Aurora Pump Co., 1522 BeU 4 Gossett Co., 1516-1517 Buffalo Pumps, Inc., 1523 Chicago Pump Co., 1524-1525 $ Decatur Pump Co., 1528 C. A. Dunham Co., 1541-1543 IngersoU-Rand, 1527 Kraigfll Co., Inc., The, 1530 . Peerless Pump Div., Food Ms-. chinery 4 Chemical Corp., 1531 X Skidmore Corp., 1532 .^j Taco Heaters, Inc., 1519 Trane Co., The, 1246-1247 Wheeler-Economy Pumps, Inc., 1533 Worthington Corp., 1192 ' PUMPS, Circulating (See Cir-:} culators) Aurora Pump Co., 1522 BeU 4 Gossett Co., 1516-1517 Buffalo Pumps, Inc., 1523 Chicago Pump Co., 1524-1525 Decatur Pump Co., 1526 IngersoU-Rand, 1527 KWiwal Co., InC., 1530 - Minneapolis-HoneyweU Regulatorx Co., 1428-1429 -f Peerless Pump Div., Food Ma chinery 4 Chemical Corp., 1531'- Numerals foUowing Manufacturers' Names refer to pages in the Catalog Data Section RADIATION, Copper Airtherm Mfg. Co., 1229 Brown Products Co., 1446 C. A. Dunham Co., 1541-1543 Feddera-Quigan Corp., 1231 G 4 O Mfg. Co., The, 1305 Kritzer Radiant Coils, Inc., 1464 5PUMPS. - Condensation RADIANT HEATING Modine Mfg. Co., 1240-1241 ^Aurora Pump Co., 1522 American Radiator 4 Standard Rome-Turney Radiator Co., The, ^Buffalo Pumps, Inc., 1523 Sanitary Corp., 1444-1445 1309 ; ^Chicago Pump Co., 1524-1525 Burnham Corp., 1450 Shaw-Perkins Mfg. Co., 1465 ^Crane Co;, 1448-1449 Campbell Heating Co., 1218-1219 Trane Co., The, 1246-1247 ?Decatur Pump Co., 1525 Crane Co., 1448-1449 Vulcan Radiator Co., The, 1310 ?C."A. Dunham Co., 1541-1543 Kritzer Radiant Coils, Inc., 1464 York-Shipley, Ino., 1513 ^Hoffman Specialty Mfg. Corp., National Radiator Co., The, 1452 Young Radiator Co., 1252 %V1544-1547 1454 u'IngersoU-Rand, 1527 Rite Engineering 4 Mfg. Corp., 1455 Nash Engineering Co., The, 1528 Sarcotherm Controls, Ine., 1557 RADIATION. Plain and Ex - 1529 Surface Combustion Corp., 1206 tended Surface ^Peerless Pump Div., Food Ma 1207 Brown Products Co., 1446 .: chinery 4 Chemical Corp., 1531 United States Radiator Corp., 1458 C. A. Dunham Co., 1541-1543 Skidmore Corp., 1532 1459 Edwards Engineering Corp., 1304 Sterling, Inc., 1440 Weil-McLain Co., 1463 Feddera-Quigan Corp., 1231 *H. A. Thrush 4 Co., 1520-1521 Wesix Electric Heater Co., 1254 G 4 O Mfg. Co., The, 1305 Trane Co., The, 1246-1247 Infra Insulation, Inc., 1602 Wheeler-Economy Pumps, Inc., 1533 Modine Mfg. Co., 1240-1241 RADIATION. Aluminum Moore Dry Kiln Co., 1306 Infra Insulation, Ino., 1602 John J. Nesbitt, Inc., 1244-1245 PUMPS, Fuel Oil Kritzer Radiant Coils, Inc., 1464 Rittling Corp., The, 1308 ^O Kraissl Co., Inc., The, 1530 Shaw-Perkins Mfg. Co., 1465 Rome-Turney Radiator Co., The, v Ray OU Burner Co., 1510-1511 Trane Co., The, 1246-1247 1309 . Vulcan Radiator Co., The, 1310 Shaw-Perkins Mfg. Co., 1465 Young Radiator Co., 1252 H. B. Smith Co., Inc., The, 1462 .. PUMPS, Sump Trane Co., The, 1246-1247 Aurora Pump Co., 1522 Vulcan Radiator Co., The, 1310 ' Buffalo Pumps, Inc., 1523 ' Chicago Pump Co., 1524-1525 'V Decatur Pump Co., 1526 RADIATION, Baseboard, Fer Warren Webster 4 Co., 1562-1564 rous Young Radiator Co., 1252 American Radiator 4 Standard ; Peerless Pump Div., Food Ma* Sanitary Corp., 1444-1445 V .. chinery 4 Chemical Corp., 1531 Brown Products Co., 1446 RADIATOR BRACKETS (See k-f-v Skidmore Corp.. 1532 Burnham Corp., 1450 Brackets, Radiator) Standard Electric Mfg Co., 1347 Crane Co., 1448-1449 -fv C. A. Dunham Co., 1541-1543 Feddera-Quigan Corp., 1231 RADIATOR ENCLOSURES PUMPS, Turbine Kritzer Radiant Coils, Inc., 1464 AND SHIELDS ' Aurora Pump Co., 1522 Rittling Corp., The, 1308 American Flange 4 Mfg. Co., Inc., Chicago Pump Co., 1524-1525 H. B. Smith Co., Inc., The, 1462 1601 Decatur Pump Co., 1528 Trane Co., The, 1246-1247 American Radiator 4 Standard ` Peerless Pump Div., Food Ma Vulcan Radiator Co., The, 1310 Sanitary Corp., 1444-1445 chinery 4 Chemical Corp., 1531 Weil-McLain Co., 1463 Brown Products Co., 1446 Skidmore Corp., 1532 Wesix Electric Heater Co., 1254 National Radiator Co., The, 1452 1454 - H. J. Somers, Inc.. 1282-1283 PUMPS, Turbine Vane Type RADIATION, Baseboard Non- Peerless Pump Div., Food Ma ferrous chinery 4 Chemical Corp., 1531 American Radiator 4 Standard RADIATOR HANGERS (See Sanitary Corp., 1444-1445 Hangers, Radiator) Brown Producte Co., 1446 PUMPS, Vacuum %. Chicago Pump Co., 1524-1525 C. A. Dunham Co., 1641-1543 Hoffman Specialty Mfg. Corp., 1544 1547 . Joy Mfg. Co., 1336-1337 V-t - Kraissl Co., Inc., 1530 Nash Engineering Co., The, 1528 1529 Skidmore Corp., 1532 Sterling, Inc., 1440 Wheeler-Economy Pumps, Inc., 1533 Worthington Corp., 1192 C. A. Dunham Co., 1541-1543 Feddera-Quigan Corp., 1231 G 4 0 Mfg. Co., The, 1305 General Automatic Products Corp., 1451 Kritzer Radiant Coils, Inc., 1464 National Radiator Co., The, 1452 1454 John J. Nesbitt, Inc., 1244-1245 Rittling Corp., The, 1308 Rome-Turney Radiator Co., The, 1309 - Shaw-Perkins Mfg. Co., 1465 H. B. Smith Co., Inc., The, 1462 RADIATOR HEAT REFLEC TORS Infra Insulation, Inc., 1602 Silvercote Products, Inc., 1605 RADIATORS. Cabinet Airtherm Mfg. Co., 1229 American Radiator 4 Standard Sanitary Corp., 1444-1445 Crane Co., 1448-1449 C. A. Dunham Co., 1541-1543 Feddera-Quigan Corp., 1231 Trane Co., The, 1246-1247 Kritzer Radiant Coils, Ino., 1464 PUMPS, Water Supply Aurora Pump Co., 1522 Decatur Pump Co., 1526 Peerless Pump Div., Food Ma- chmery 4 Chemical Corp., 1531 Sterling, Inc., 1440 Wheeler-Economy Pumps, Inc., 1533 Tuttle 4 Bailey, Inc., 1394-1395 United States Radiator Corp., 1453 1459 Vulcan Radiator Co., The, 1310 Warren Webster 4 Co., 15G2-1564 York-Shipley, Inc., 1513 Modine Mfg. Co., 1240-1241 National Radiator Co., The, 1452 1454 Rittling Corp., The, 1308 Shaw-Perkins Mfg. Co., 1465 United States Radiator Corp., 1458 1459 Weil-McLain Co., 1463 RADIATION, Cast-Iron Young Radiator Co., 1252 PURGERS, Refrigeration American Radiator 4 Standard Sanitary Corp., 1444-1445 Anastrong Machine Works, 1536 Burnham Corp., 1450 ` 1537 Crane Co., 1448-1449 York Corp., 1193 D. J. Murray Mfg. Co., 1239 RADIATORS, Concealed Airtherm Mfg. Co., 1229 American Radiator 4 Standard National Radiator Co., The, 1452 Sanitary Corp., 1444-1445 1454 Crane Co., 1448-1449 j, PURIFIERS AND SCRUBBERS, United States Radiator Corp., 1458 C. A. Dunham Co., 1541-1543 'a ..Air, Gas and Steam 1459 Feddera-Quigan Corp., 1231 c- V. D. Anderson Co., The, 1534-1535 Weil-McLain Co., 1463 Kritzer Radiant Coils, Inc., 1464 Please mention THE GUIDE 1954 when writing to Advertisers 1162 1954 Guide! Modine Mfg. Co., 1240-1241 Ready-Power Co., The, 1315 Penn Controls, Inc., 1432 ... National Radiator Co., The, 1452 Refrigeration Engineering, Inc., 1316 White-Rodgers Electric Co., 1442 jg 1454 Servel, Inc., 1204-1205 Rittling Corp., The, 1308 Trane Co.; The, 1246-1247 Shaw-Perkina Mfg. Co., 1465 Worthington Corp., 1192 United States Radiator Corp., 1458 York Corp., 1193 REGULATORS. Gas .... General Controls, 1418-1419 1459 Vulcan Radiator Co., The, 1310 Warren Webster A Co., 1562-1564 Weil-McL&in Co., 1463 Young Radiator Co., 1252 REFRIGERATION CONTROLS Aloo Valve Co., Inc., 1410 General Controls, 1418-1419 Hubbell Corp., The, 1421 Maxitroi Co., 1426 . Minneapolis^Honeywell Regulatorll Co., 1428-1429 Penn Controls, Inc., 1432 , Webster Engineering Co., The, 1509 fl Merooid Corp., The, 1427 . RANGES, Cooking. Hotel, Hos Penn Controls, Inc., 1432 pital, etc. Schnacke, Inc., 1317 Air Devices, Inc., 1261, 1372 White-Rodgers Electric Co., 1442 REGULATORS, Humidity (Seel Humidity Control) ** Ray Oil Burner Co., 1510-1511 REGULATORS, Pressure REGISTERS (See Grilles, Louvers) Alco Valve Co., 1410 RECEIVERS, Air Air Control Products, Inc., 1368 Bell A Gossett Co., 1516-1517 Curtis Refrigerating Machine Div. 1371 C. A. Dunham Co., 1541-1543 of Curtis Mfg. Co., 1312 Auer Register Co., The, 1373 Farrar A Trefte, Inc., 1473 Barber-Column Co., 1376, 1411 International Boiler Works Co., Dole Valve Co., Tim, 1565 The, 1476 Hart A Cooley Mfg. Co., 1380-1381 Eddington Metal Specialty Co., 1505$ Fulton Sylphon Div., The Robert-?? ehaw-Fulton Controls Co., 1416-$i 1417 ** Joy Mfg. Co., 1336-1337 Worthington Corp., 1192 Hendrick Mfg. Co., 1382-1383 General Controls, 1418-1419 . Independent Register Co., The, 1384 Hoffman Specialty Mfg. Carp.,-, Pyle-National Co., The, (Multi 1644-1547 3 Vent Div.), 1386-1388 Hubbell Corp., The, 1421 RECEIVERS, Condensation Register A Grille Mfg. Co., Inc., Illinois Engineering Co., 1548-1549 Hoffman Specialty Mfg. Corp., 1544 1389 Johnson Service Co., 1422-1423 1547 Standard Stamping A Perforating Leslie Co., 1435 Illinois Engineering Co., 1548-1549 Co., 1390 Jss. P. Marsh Corp., 1552-1553 Worthington Corp., 11OT Stewart Mfg. Co., Inc., 1391 Maxitroi Corp., 1426 . Titus Mfg. Corp., 1392-1393 McDonnell A Miller, Inc., 1490-1493^ Tuttle A Bailey, Inc., 1394-1395 Mercoid Corp., The, 1427 RECEIVERS, Refrigerants United States Register Co., 1396-- Monarch Mfg. Works, Inc., 1299 Acme Industries, Inc., 1300 1397 Killebrew Engineering Corp., 1518 Waterloo Register Co., Inc., 1399 Penn Controls, Inc., 1432 Perfex Corp., 1433 . Worthington Corp., 1192 Young Regulator Co., 1401 Powers Regulator Co., The,1434-j^ York Corp., 1193 1436 Spence Engineering Co., Inc., 1439 REGULATORS, Air Volume Strong, Carlisle A Hammond RECORDERS, Humidity, Tem Barber-Colman Co., 1376, 1411 1560 m perature Minneapolis-Honeywell Regulator Swartwout Co., The, 1365 i American Moistening Co., 1174 Co., 1428-1429 H. A. Thrush A Co., 1520-1521 'M Electric Auto-Lite Co., The. Instru Powers Regulator Co., 1434-1436 Webster Engineering Co., The, 1509 ; ment A Gauge Div., 1414 Young Regulator Co., 1401 Johnson Service Co., 1422-1423 Moeller Instrument Co., 1431 REGULATORS, Remote Con-s5 Powers Regulator Co., The, 1434 REGULATORS, Back Pressure trol ' 1436 Aloo Valve Co., 1410 Alco Valve Co., 1410 Taylor Instrument Cos., 1441 Hubbell Corp., 1421 Hubbell Corp., 1421 * Mercoid Corjx, The, 1427 ^ Minneapolis-Honeywell Regulator % REFRACTORIES, Cement, Ma REGULATORS, Damper terials Barber-Column Co., 1376, 1411 Co., 1428-1429 Penn Controls, Inc., 1432 Armstrong Cork Co. (Building Ma Duro-Dyne Corp., 1400 Perfex Corp., 1433 terials Div.), 1587 Field Control Div., of H. D. Conkey Powers Regulator Co., 1434-1436 Babooek A Wilcox Co., The, 1466 A Co., 1415 Sterling, Inc., 1440 Philip Carey Mfg. Co., The, 1580 Hart A Cooley Mfg. Co., 1380-1381 Young Regulator Co., 1401 1581 Minneapolis-Honeywell Regulator Johns-Manville, 1592-1593 Co., 1428-1429 Powers Regulator Co., The, 1434 REGULATORS, Temperature^ 1436 (See Temperature Control) 'ifj|| REFRIGERATING EQUIP Spence Engineering Co., Inc.. 1439 MENT, Centrifugal Trane Co., The, 1246-1247 Bell A Gossett Co., 1516-1517 Warren Webster A Co., 1562-1564 REGULATORS, Time Controls^ Carrier Corp., 1178-1179 Young Regulator Co., 1401 General Controls, 1418-1419 Trane Co., The, 1248-1247 Minneapotis-Honeywell Regulator s Worthington Corp., 1192 York Corp., 1193 REGULATORS, Draft Field Control Div., of H. D. Conkey A Co., 1415 Co., 1428-1429 Perfex Corp., 1433 Powers Regulator Co., 1434-1436 ' REFRIGERATING EQUIP- Simplex Mfg. Co., 1438 v MENT, Steam Jet RELIEF VALVES (See Valves,] Ingerso11-Rand, 1527 Worthington Corp., 1192 REGULATORS, Evaporator Pressure Relief) Aloo Valve Co., 1410 REFR1GERATING MACHIN- Hubbell Corp., The, 1421 RESTRICTOR TUBING (See Tubing, Restrictor) * AERY . i irtemp Div., Chrysler Corp., 1195- f 1197 Brunner Mfg. Co., 1311 REGULATORS. Feed Water McDonnell A Miller, Inc., 1490-1493 ROOF COOLER April Showers Co., Inc., 1569 Carrier Corp., 1178-1179 Curtis Refrigerating MtuhinA Div. REGULATORS, Furnace ROOM COOLER of Curtis Mfg. Co., 1312 Field Control Div., of H. D. Conkey Utility Appliance Corp., 1208-1209 Frick Co., 1313 A Co., 1415 Frigidaire Div., General Motors Merooid Corp^ The, 1427 Corp., 1184 Minneapolis-Honeywell Regulator RUST PREVENTATIVE (See Cor- jg Niagara Blower Co., 1186 Co., 1428-1429 rosion, Treatment of) * sa Numerals following Manufacturers' Names refer to pages in the Catalog Data Section Hates to Modern Equipment 1163 SAFETY CONTROLS (See Burner SHEETS, Stainless Steel Bahnson Co.. The, 1176-1177 ^Protection, Gas and Off) American Flange A Mfg. Co., Inc., Biliks Mfg. Co., 1290-1291 -- 1601 Buensod-Stacey, Inc., 1175 United States Steel, 1367 Buffalo Forge Co., 1325 SAFETY VALVES (See Valves, Eddington Metal Specialty Co., 1505 ^Safety) SHEETS. Steel Fluor Corp., Ltd., The, 1292 Marley Co., The. 1296 American Flange A Mfg. Co., Inc., Monarch Mfg. Works, Inc., 1299 ^SCREENING SHADE (See Shade 1601 D. J. Murray Mfg. Co., 1239 ' Screening) United States Steel, 1367 ParkB-Cramer Co., 1188-1189 J. F. Pritchard A Co., 1297 jpfe- ' Yarnall-Waring Co., 1561 ^SCREENS, Perforated Metal SHUTTERS, Automatic ^Hendrick Mfg. Co,, 1382-1383 American Coolair Corp., 1319 [$ American Foundry A Furnace Co., STEAM AND WATER MIXERS 1214-1215 (See Mixers, Steam and Water) ^SEPARATORS, Air Dole Valve Co., The. 1565 Ry.D. Andereon Co., The, 1534-1535 Duro-Dyne Corp., 1400 5-Baroebey-Cheney Co., 1268-1269 ^Dollinger Corp., 1274-1275 IW^H/Nicholson A Co.. 1554-1555 Hunter Fan and Ventilating Co., STEAM GENERATORS, Unit 1334 Babcock A Wilcox Co., The, 1466 Ilg Electric Ventilating Co., 1234, Cleaver-Brooks Co., 1467, 1495 j-pur Air Div., Bamebey-Cheney 1335 Combustion Engineering, Inc., 1468 feCo., 1268-1269 Herman Nelson Div., American Air 1469 ^Strong, Carlisle A Hammond Co., Filter Co., Inc., 1242-1243 ^gv-1560 Reed Unit-Fans, Inc., 1344 Cydotherm Div., U. S. Radiator Corp., 1470 Ltandard Electric Mfg. Co., 1347 Dutton Boilers, Div. Hapman- S. J. Wing Mfg. Co., 1249-1251 Dutton Co., 1472 ,,.."SEPARATORS, Dust Foster Wheeler Corp., 1293 American Air Filter Co., 1265-1267 Johnston Brothers. Inc., 1477 r^V. D. Anderson Co., The, 1534-1535 SKYLIGHTS. Insulated Orr A Sembower, Inc., 1478 Jb-:? Dellinger Corp., 1274-1275 Owens-Illinois Glass Co., 1577 Titusville Iron Works Co., 1484-1485 f?*r Pittsburgh Corning Corp., 1578 Vapor Heating Corp., 1487 ^SEPARATORS, Gas Worthington Corp., 1192 York-Shipley, Inc., 1513 D. Anderson Co., The, 1534-1535 SMOKE DETECTORS AND IN DICATORS (For Flues and ^ SEPARATORS. Oil fesfe Acme Industries, Inc., 1300 Ducts) Combustion Control Corp., 1413 Trion, Inc., 1285 STEAM HEATING SYSTEMS (See Heating Systems, Steam) Ss.^Air-Maxe Corp., 1262-1263 * ^ .Dollinger Corp., 1274-1275 Illinois Engineering Co.. 1548-1549 ^ Kraiasl Co., Inc., The, 1530 SOOT DESTROYER John Zink Co., 1502-1503 STEEL INSULATION (See in sulation, Steel) p-Yark Corp., 1193 SOOT REMOVER SEPARATORS, Refrigerant OU Economy Flue Cleaner Co., 1494 Acme Industries, Inc., 1300 STOKER MOTORS (See Motors, Electric) SEPARATORS. Steam American District Steam Co.. Inc.. 1402--1403 g. V. D. Anderson Co., The, 1534-1535 Illinois Engineering Co., 1548-1549 W. H. Nicholson A Co., 1554-1555 Strung, Carlisle A Hammond Co., SOUND ISOLATORS Barry Corp., The, 1320 SOUND DEADENING (See Vibra tion Absorbers) STOKERS, Mechanical, Anthra cite Airtemp Div., Chrysler Corp.. 1196 1197 Combustion Engineering, Inc., 1468 1469 Detroit Stoker Co., 1488 gy: SEPARATORS, Vapor V. D. Anderson Co., The, 1534-1535 Sip SHADE SCREENING HcV "geraoll Products, Div. Borg ' Warner Corp., 1603 SHEETS, Asbestos, Flat, and Spfi . Corrugated fej Carey Mfg. Co., The, 1580 1' Johns-Manville, 1592-1593 ` SHEETS, Copper Alloy Es? Amencwa Brass Co., The, 1256-1257 i&C Revere Copper A Brass, Inc., 1259 fg; &* CopP**1 Bearing Steel Uwted States Steel, 1367 pr' SHEETS, Galvanized 5|= United States Steel, 1367 M Tensile United States Steel, 1367 % Special Finish j-umted States Steel, 1367 SPRAY DRYER (See Spray Equip ment) SPRAY EQUIPMENT Bayley Blower Co., 1321 Binks Mfg. Co., 1290-1291 Eddington Metal Specialty Co., 1505 Monarch Mfg. Works, Inc., 1299 D. J Murray Mfg. Co., 1239 ` Yarnall-Waring Co., 1561 SPRAY NOZZLE COOLING SYSTEM American Moistening Co., 1174 April Showers Co., Inc., 1569 Bahnson Co., The, 1176-1177 Binks Mfg. Co., 1290-1291 Eddington Metal Specialty Co., 1505 Fluor Corp., Ltd., The, 1292 Lilie-Hoffman Cooling Towers, Inc., 1295 Marley Co., The, 1296 Monarch Mfg. Works, Inc.. 1299 D. J. Murray Mfg. Co., 1239 J. F. Pritchard A Co., 1297 Santa Fe Tank A Tower Co., 1298 Yarnall-Waring Co., 1561 SPRAY NOZZLES American Moistening Co.. 1174 April Showen Co., Inc., 1569 STOKERS. Mechanical. Bitu minous Airtemp Div., Chrysler Corp., 1196 1197 Combustion Engineering, Inc., 1468 1469 Crane Co., 1448-1449 Detroit Stoker Co., 1488 WiU-Burt Co., The, 1489 STOKERS, Refuse Burning Combustion Engineering, Inc., 1468 1469 Detroit Stoker Co., 1488 STRAINERS, Air Maid-O'-Mist, Inc., 1550-1551 W. H. Nicholson A Co., 1554-1555 STRAINERS, Dirt V. D. Anderson Co., The, 1534-1535 Armstrong Machine Works, 1536 1537 C. A. Dunham Co., 1541-1543 Hoffman Specialty Mfg. Corp., 1544-1547 Illinois Engineering Co., 1548-1549 Kraissl Co., Inc., The, 1530 W. H. Nicholson A Co., 1554-1555 Sarco Co., Inc., 1558-1559 Sterlingjlnc., 1440 Warren Webster A Co., 1562-1564 Yarnall-Waring Co., 1561 Please mention THE GUIDE 1954 when writing to Advertisers 1164 STRAINERS, Gas Hubbell Corp., 1421 ^ Maid-O'-Mist, Inc., 1550-1651 W. H. Nicholson & Co., 1654-1555 STRAINERS, Oil _ V. D. Andereon Co., The, 1534-1535 Annstrong Machine Works, 1530- 1537 Bell A Gossett Co., 1516-1517 Eddington Metal Specialty Co., 1505 Hu*b.bel.l >C. orn., mThl e_ , ,14.A21. frugal Co., Inc., The. 1530 SWITCHES, PttCi Powers Regulator Co., 1434-1436_ .... ......... , SWITCHES.Stack Safe. ty Minneapolis-Honeywell Regulator Co., 1428-1429 7 1 1Penn Controls, Inc., 1432 UWIh.*iAtea-Ro-d^g--e--rs- IErlAleActtMriAc IC.o., 1442 Fulton-Sylphon Div., The, Robert? shaw-Fulton Controls Co., 1416^ 1417 . ^ Illinois Testing Laboratories, Inc:| 3424 ' Jas. P. Marsh'Corp., 1552-1553 , Minneapolis-Honeywell Regulator! Co., 1428-1429 Moeller Instrument Co., 1431 ' Powers Regulator Co., The, 1434-j 1436 Sarco Co., Inc., 1558-1559 Taylor Instrument Cos., 1441 Monarch M/g- Works. Inc., 1299 W. H. Nicholson A Co., 1554-1555 Sarco Co., Inc., 1658-1559 Spence Engineering Co., Inc., 1439 Sterling, Inc., 1440 STTRAINERS, Refrigerant Alco Valve Co., 1410 General Controls, 1418-1419 Henry Valve Co., 1420 Hubbell Corp., The, 1421 Maid-O'-Mist, Inc., 1550-1551 Penn Controls, Inc., 1432 Sarco Co.. Inc., 1558--1559 Sterling, Inc., 1440 STRAINERS. Steam SWITCHES, Time April Showers, Inc., 1569 TEHleEctRricMAOuMtoE-LTiEteRCSo,.,InTdhiec,aIntisntrgu-J^S ment & Gauge Div., 1414 Fulton Sylphon Div., The, Robert^ TANK COILS (See Coils, Tank) shaw-Fulton Controls Co., 1416^? 1417 . .% Tiiinoin Testing Laboratories, Inc.',^ TANK COVERING (See Covering 1424 Pips) Johnson Service Co., 1422--1423 Jas. P. Marsh Corp., 1552-1553 Minneapolis-Honeywell Regulator? TANK HEATERS (See Heaters, Co., 1428-1429 ** Tank) Moeller Instrument Co., 1431 , Powers Regulator Co., The, 1434-.* 1436 TANKS, Blow-off Rochester Mfg. Co., 1437 International The, 1476 Boiler Works Co., Sarco Co., Inc., 1558-1559 Taylor Instrument Coe., 1441 Alco Valve Co., 1410 American District Steam Co., Inc. 1402-1403 V. D. Anderson Co., The, 1534-1535 AArrmWstfrromnigr Machine Works,. 1536- 1537 Crane Co., 1448-1449 C. A. Dunham Co., 1541-1543 Grinnell Co., Inc., 1232--1233. Illinois Engineering Co.. 1548-1549 Kraissl Co., Inc., The, 1530 Leslie Co., 1425 Maid-O'-Mist, Inc., 1SSO-35S1 TANKS, Pressure Farrar A Trefts lnc., 1473 International Boiler Works The, 1476 Trane Co., The, 1246-1247 Go., TANKS, Storage Rheem Mfg. Co., 1202-1203 Santa Fe Tank A Tower Co., 1298 Western Blower Co., 1352 THERMOMETERS, Recording Electric Auto-Lite Co., The, Instru-- ment A Gauge Div., 1414 Johnson Service Co., 1422-1423 Minneapolis-Honeywell Regulator^ Co., 1428-1429 M Moeller Instrument Co., 1431 ^ Powers Regulator Co., The, 1434-|g 1436 THERMOSTATS W. H. Nicholson A Co., 1554-1555 Barber-Colman Co., 1376, 1411 Sarco Co., Inc., 1558-1559 Spence Engineering Co., Inc., 1439 Sterling, Inc., 1440 Strong, Carlisle A Hammond Co., 1560 Trane Co., The, 1246-1247 STRAINERS. Water Alco Valve Co.. 1410 V. D. Andereon Co., The, 1534-1535 TEMPERATURE CONTROL American Flange A Mfg. Co., Inc., 1601 Barber-Colman Co., 1376, 1411 Cam-Stat, Inc., Div. of the Paul Henrv Co., 1412 Crane Cd., 1448-1449 C. A. Dunham Co., 1541-1543 Fulton-Sylphon Div., The, Rolbieifrit-- shaw-Fulton Controls Co- lU9~ Cam-Stat, Inc., Div. of the Paul/!* Henry Co., 1412 .ijL Crane Co., 1448-1449 , Fulton Sylphon Div., The, Robert-^ shaw-Fulton Controls Co., 1416-^a 1417 General Controls, 1418-1419 Hoffman Specialty Mfg.Corp.J| 1544-1547 ,, Johnson Service Co.,1422-1423 -^Jl Mercoid Corp., The, 1427 ,x Armstrong Machine Works, 1536 1537 Eddington Metal Specialty Co., 1505 1417 GHoenffemraalnCoSntpreocl.sia-, l1ty418-M14f1g9. Corp., Minneapolis-Honeywell Regulator^ Co., 1428-1429 Penn Controls, Inc., 1432 ~R Hubbell Corp., The, 1421 Illinois Engineering Co., 1548-1549 Co., Inc., The, 1530 Leslie Co., 1425 Maid-O'-Mist, Inc., 1550-1551 Monarch Mfg. Works. Inc., 1299 1544-1547 Illinois Engineering Co., 1548-1549 Illinois Testing Laboratories, Inc. 1424 Johnson Service Co., 1422-1423 Leslie Co., 1425 Perfex Corp., 1433 Powers Regulator Co., The, 1434^ 1436 Sarco Co., Inc., 1558-1559 Sarcotherm Controls, Inc., 1557 H. A. Thrush A Co., 1520-1521 W. H. Nicholson A Co., 1554-1555 Penn Controls, Inc., 1432 Sarco Co., Inc., 1558-1559 Spence Engineering Co., Inc., 1439 Sterling, Inc-, 1440 TraneCo., The, 1246-1247 Yarnall-Waring Co., 1561 Co., 1428-1429 Penn Controls, Inc., 1432 Perfex Corp. 1433 Powers Regulator Co., The, 1434 1436 Sarco Co., Inc., 1558-1559 White-Rodgers Electric Co., 1442 TIME SWITCHES (See Switches,* Time) ~ SWITCHES, Electric and Time April Showers Co., 1569 Sarcotherm Controls, Inc., 1557 Spence Engineering Co., Inc., 1439 Sterling, Inc., 1440 Taylor Instrument Coe., 1441 Warren Webster A Co., 1562-1564 TIMERS, Electric; Interval Barber-Colman Co., 1376, 1411 ~ Photoewitch, Inc., (Affiliatei OLR Combustion Control Corp.), 14W$s SWITCHES. Float Alco Valve Co., 1410 McDonnell A Miller, Inc., 1490-1493 Mercoid Corp., The, 1427 Wesix Electric Heater Co., 1254 Young Regulator Co., 1401 TEMPERING VALVES (iSee TIMERS, Electric, Sequence ** Photoewitch, Inc., (Affiliate of Co*|8 bustion Control Corp.), 1413 ' SWITCHES, Flow Control Valves, Tempering) TOWERS, Cooling, (See Coding^ McDonnell A Miller, Inc., 1490-1493 THERMOMETERS, Distance Towers) SWITCHES, Mercury Mercoid Corp., The, 1427 Type Electnc Auto-Lite Co., The Instru TRANSFORMERS ment A Gauge Div., 1414 Aldrich Co., 1443 Numerals following Manufacturers* Names refer to pages in the Catalog Data Section 1165 TRAPS, Scale, Refrigerant . TUBING. Finned Henry Valve Co., 1420 Aerofin Corp., 1301-1303 Edwards Engineering Corp., 1304 STRAPS, Air ' jVf.p: Anderson Co., The, 1534-1535 rmstrbng Machine Works, 1538 .--1537: - Nicholson A Co., 1554-1555 ^Sarco Co.. Inc., 1558-1559 'Strong, Carlisle A Hammond Co., ^.1560 ' ' TRAPS, Steam - V. D. Anderson Co.. The, 1534-1535 Armstrong Machine Works, 1536 1537 . Barnes A Jones, Inc.,1539 Crane Co., 1448-1449 C. A. Dunham Co.. 1541-1543 Hoffman Specialty Mfg. Corp.. GAO Mfg. Co., The, 1305 Kritzer Radiant Coils, Inc., 1464 Moore Dry Kiln Co., 1306 Refrigeration Economics Co., Inc.. 1248 Rittling Corp., The, 1308 Rome-Tumey Radiator Co., The. 1309 Wolverine Tube Div. of Calumet A W--: TRAPS. Buckets JV/'D. Andereon Co., The, 1534-1535 :%Xirhstrong Machine Works, 1536- -1537 ?Crane Co., 1448-1449 ,^C.-A.,Dunham Co., 1541-1543 i'&Hoffm&n Specialty Mfg. Corp., 'fe./1544-1547 ^ Jas/P. Marsh Corp., 1552-1553 Sarco Co., Inc., 1558-1559 ^Strong, Carlisle A Hammond Co., *.`1660 Trane Co., The, 1246-1247 1544-1547 . Illinois Engineering Co., 1548-1549 Jas. P. Marsh Corp., 1552-1553 W. H. Nicholson A Co., 1554-1555 Powers Regulator Co., The, 1434 1436 Sarco Co., Inc., 1558-1559 Sterling, Inc., 1440 Strong, Carlisle A Hammond Co., 1560 Trane Co., The, 1246-1247 Vapor Heating Corp., 1487 Warren Webster A Co., 1562-1564 Yarnall-Waring Co., 1561 - - Heda, Inc., 1260 TUBING. Flexible Metallic American Brass Co., The, 1256-1257 Flexonics Corp., Chicago Metal Hose Div., 1258 TUBING RESTRICTOR American Brass Co., The, 1256-1257 TUBING. Steel Revere Copper A Brass, Inc., 1259 TRAPS, Float TRAPS, Thermostatic 'American District Steam Co., Inc., Barnes A Jones, Ine., 1539 1402-1403 Crane Co., 1448-1449 . Wolverine Tube Div. of Calumet A Hecla, Inc., 1260 V. D. Andereon Co., The, 1534-1535 C. A. Dunham Co., 1541-1543 TURBINES 'Armstrong Machine Works, 1536 1537 *; Barnes A Jones, Inc., 1539 4 Crane Co., 1448-1449 -7 C; A. Dunham Co., 1541-1543 Grinnell Co., Inc., 1232-1233 Hoffman Specialty Mfg. Corp., 1544-1547 Illinois Engineering Co., 1548-1549 Jas. P. Marsh Corn.. 1552-1553 Pyle-National Co., The, 1386-1388 L. J. Wing Mfg, Co.. 1249-1251 Worthington Corp., 1192 * Illinois Engineering Co., 1548-1549 Jm. P. Marsh Corp., 1552-1553 &8^S. W. H. Nicholson A Co., 1554-1555 Sarco Co., Inc., 1558-1559 W. H. Nicholson A Co., 1554-1555 Powers Regulator Co., The, 1434 1436 Sarco Co., Inc., 1558-1559 UNDERGROUND PIPE CON DUITS (See Conduits, Under ground Pipe) Trane Co., The, 1246-1247 Sterling. Inc.. 1440 Trane Co., The, 1246-1247 UNIT HEATERS (See Heaters, Warren Webster A Co., 1562-1564 TRAPS, Float and Thermostatic Unit) American District Steam Co. Inc., 1403-1403 V. D. Aadeison Co., The, 1534-1535 .Barnes & Jones, lac., 1539 C. A. Dunham Co., 1541-1543 Gnaaell Co., Ino., 1232-1233 : Bjgj^Bp-bRy Mfg. Corp., TRAPS, Vacuum V. D. Andereon Co., The, 1534-1535 Armstrong Machine Works, 1536 1537 Barnes A Jones, Inc., 1539 Illinois Engineering Co., 1548-1549 UNIT VENTILATORS (See Ven tilators, Unit) UNITS, Air Conditioning (See Air Conditioning Units) Illinois Engineering Co., 1548-1549 m-. Corp., 1552-1553 W. H. Nicholson & Co., 1554-1555 Sarco Co lne., 1558-1559 Jas. P. Marsh Corp.. 1552-1553 Strong, Carlisle A Hammond Co.. 1560 VACUUM HEATING SYSTEMS (See Heating Systems, Vacuum) sterling, Inc., 1440 TUBES, Boiler " W5(f' * Hammond Co., Babcock A Wilcox Tube Co., The, VACUUM REFRIGERATING Trane Co., The. 1246-1247 Warren Webster & Co.. 1562-1564 1466 SYSTEMS IngeraoU-R&nd, 1527 vl' TRAPS, Radiator Barnes A Jones, Ino., 1539 j Crane Co., 1448-1449 C. A. Dunham Co., 1541-1543 S"11 Co., Inc.. 1232-1233 l&547SBedalty "* Cor>" Illinois Engineering Co., 1548-1549 Jas. P. Marsh Corp., 1552-1553 s,-Nicholson A Co., 1554-1555 "Jarling. Ine., 1440 Co.. The, 1246-1247 Warren Webster A Co., 1562-1564 TRAPS, Return Co-. 1448-1449 Dunham Co., 1541-1643 &547Spe<:Uty Mfg- CorP- J^P8 SnEi?ecrin Co., 1548-1549 ^Mai?h Corp., 1552-1553 S500 Co., Inc.. 1558-1559 Inure Co., The, 1246-1247 TRAPS. Scale Henry Valve Co., 1420 Illinois Engineering Co., 1548-1549 TUBES, Copper American Brass Co., The, 1256-1257 Revere Copper A Brass, Inc., 1259 Wolverine Tube Div. of Calumet A Hecla, Inc., 1260 VALVES Air V. D. Andereon Co.. The, 1534-1535 Crane Co., 1448-1449 Dole Valve Co., The. 1565 Fairbanks Co., The, 1566 Hammond Brass Works, 1567 - TUBES, Pitot (See Air Measuring and Recording Instruments) Hoffman Specialty 1544-1547 Mfg. Corp.. Jenkins Bros., 1568 Maid-O'-Mist, Inc., 1550-1551 TUBING, Aluminum ' American Brass Co., The, 1256-1257 Revere Copper A Brass, Inc., 1259 Wolverine Tube Div. of Calumet Jas. P. March Corp., 1552-1553 . W. -H. Nicholson A Co., 1554-1555 Ohio Brass Co.. 1556 Taco Heaters, Inc., 1519 A Heda, Ine., 1260 VALVES. Angle, Globe and Cross TUBING, Copper American Brass Co., The, 1256-1257 Revere Copper A Brass, Inc., 1259 Wolverine Tube Div. of Calumet A Heda, Inc., 1260 ' Crane Co., 1448-1449 Fairbanks Co., The, 1566 Frick Co., 1313 Grinnell Co., Inc., 1232-1233 Hammond Brass Works, 1567 Henry Valve Co., 1420 Jenkins Bras., 1568 TUBING, Fabricated Ohio Brass Co., 1556 Revere Copper A Brass. Inc., 1259 Wolverine Tube Div. of Calumet A VALVES, Automatic Hecla, Inc., 1260 Barber-Colman Co., 1376, 1411 Please mention THE GUIDE 1954 when writing to Advertisers Dole Valve Co.. 1565 Fulton Sylphon Div., The. Bobert- shaw-Fulton Controls do.. 1415 1417 General Controls, 1418-1419 Hubbell Corp., The. 1421 Johnson Serviee Co., 1422-1423 Jas. P. Marsh Corp., 1552-1553 McDonnell A Miller, Inc.; 1490-1493 Minneapolis-Honeywell Regulator Co., 1428-1429 Penn Controls, Inc., 1432 Powers Regulator Co., The, 1434 1435 Sarpotherm Controls, Inc., 1557 Sterling, Ine., 1440 White-Rodgers Electric Co., 1442 VALVES, Flow Control Bell A Gcesett Co.. 1515-1517 : Crane Co., 1448-1449 Dole Valve Co., 1565 Fulton Sylphon Div., The, Robert- shaw-Fulton Controls do., 1416 1417 General Controls, 1418-1419 Illinois Engineering Co., 1548-1549 Jas. P. Marsh Corp., 1552-1553 McDonnell A Miller, Inc., 1490-1493 Ohio Brass Co., 1555 Powers Regulator Co., The, 1434 1436 Sterling, Inc., 1440 Taco Heaters, Inc., 1519 H. A. Thrush & Co., 152CM521 Fulton Sylphon Div.. The, lw_ ahaw-Fulton Controls Co.,-jl4l 1417 -'2T General Controls, 1418-1419 Henry Valve Co., 1420 Hoffman Specialty Mfg. 1544-1547 Illinois Engineering Co., 1548-1549 Johnson Servioe Co., 1422-1423 ?' Jas. P. Marsh Corp., 1552-1553 ^ Minneapolis-Honeywell Regular Co.. 1428-1429 Ohio Brass Co., 1556 Powers Regulator Co., The, 1 " 1436 Saroo Co., Inc., 1558-1559 Sterling, Inc., 1440 VALVES, Back Pressure Aleo Valve Co., 1410 General Controls, 1418-1419 Hubbell Carp., The, 1421 Illinois Engineering Co., 1548-1549 VALVES. Gas Fairbanks Co., The, 1566 Hammond Brass Works, 1567 Jenkins Bros., 1568 Ohio Brass Co., 1556 Penn Controls, Inc., 1432 Perfex Corp., 1433 VALVES, Pressure Redu (Ses Regulators, Pressure) VALVES. Radiant Heating.;. Hammond Brass Works, 1557 Ohio Brass Co., 1556 Jl VALVES, Balancing White-Rodgers Electric Co., 1442 General Controls, 1418-1419 Hammond Brass Works, 1567Illinois Engineering Co.. 1548-1549 Johnson Serviee Co., 1422-1423 Maid-O'-Mist Inc., 1550-1551 -McDonnell A Miller, Inc., 1490-1493 Minneapolis-Honeywell Regulator Co., 1428-1429 Ohio Brass Co., 1556 VALVES, Gate Crane Co., 1448-1449 Fairbanks Co., The, 1566 General Controls, 1418-1419 Hammond Brass Works, 1567 Jenkins Bits., 1568 Ohio Brass Co., 1556 VALVES. Radiator American Radiator A Standi Sanitary Corp., 1444-1445 ' Barnes A Jones, Inc., 1539 Crane Co., 1448-1449 C. A. Dunham Co., 1541-1543 "s Fairbanks Co., The, 1566 ? Fulton Sylphon Div., The, Rob shaw-Fulton Controls Co., 141 VALVES, Blowoff Fairbanks Co., The, 1566 Jenkins Bros., 1568 Yarnall-Waring Co., 1561 VALVES, By-Pass General Controls, 1418-1419 Jenkins Bros.. 1568 Johnson Service do., 1422-1423 Ohio Brass do., 1556 VALVES, Check Fairbanks Co., The, 1566 GrinneU Co., Inc., 1232-1233 Hammond crass Works, 1567 Henry Valve Co.* 1420 Hubbell Corp., The, 1421 VALVES. Humidifier Maid-O'-Mist, Inc., 1550-1551 McDonnell A Miller, Inc., 1490-1493 VALVES. Hydraulic Fairbanks Co., The, 1566 Jenkins Brae., 1568 W. H. Nicholson A Co., 1554-1555 Yarnall-Waring Co., 1561 VALVES. Magnetic Alco Valve Co.. 1410 General Controls, 1418-1419 Hubbell Corp., The, 1421 McDonnell A Miller, Inc., 1490-1493 Milwaukee Gas Specialty Co., 1430 Penn Controls, Inc., 1432 1417 GrinneU Co., Inc., 1232-1233 - Hammond Brass Works, 1567 Hoffman Specialty Mfg. Corp;, 1544-1547 niiniita Engineering Co., 1548-1549 Jenkins Bros., 1568 " Maid-O'-Mist, Ine., 1550-1551 . Jas. P. Merab Corp., 1552-1553 f Minneapolis-Honeywell Regula Co., 1428-1429 Ohio Brass Co., 1556 , Powers Regulator Co., The, 1 1436 * Saroo Co., Ino., 1558-1559 Sterling, Inc., 1440 `" Taco Heaters, Inc., 1519 Trane Co., The, 1246-1247 - United States Radiator Corp., 145jh 1459 Jenkins Bros., 1568 Ohio Braes Co., 1556 VALVES, Miring, Thermostatic Dole Valve Co., 1565 VALVES. Radiator, Convector. Fulton Sylphon Div., The, Robert- Powers Regulator Co., The, 14? VALVES, Corrosion Resisting Crane Co., 1448-1449 Jenkins Brae., 1568 . shaw-Fulton Controls do., 1416 1417 Powers Regulator Co., The, 1434 1436 1436 ` VALVES. Radiator. HumldUj;- VALVES, Diaphragm Saroo Co., Inc., 1558-1559 Mahf-O'-Mist, Inc.. 1550-1551 Crane Co.. 1448-1449 General Controls. 1418-1419 Grinnell Co., Inc., 1232-1233 Henry Valve Co., 1420 Hubbell Corp.. The, 1421 Johnson Service Co., 1422-1423 Penn Controls, Ine., 1432 Powers Regulator Co., The, 1434 1436 Taylor Instrument Coe., 1441 White-Rodgers Electric Co., 1442 VALVES, Expansion Alco Valve Co., 1410 Crane Co., 1448-1449 General Controls, 1418-1419 Henry Valve Co., 1420 VALVES, Motor Operated Barber-Colman Co., 1376, 1411 Bell A Gossett Co., 1516-1517 General Controls, 1418-1419 Illinois Engineering Co., 1548-1549 Johnson Service Co., 1422-1423 Milwaukee Gas Specialty Co., 1430 W. H. Nicholson A Co., 1554-1555 Penn Controls, Inc., 1432 Powers Regulator Co., The, 1434 1436 Saroo Co., Ine., 1558-1559 Warren Webster A Co., 1562-1564 VALVES, Non-Return Fairbanks Co., The, 1566 Hammond Brass Works, 1567 VALVES. Radiator Orifice Barnes A Jones, Ine., 1539 * C. A. Dunham Co., 1541-1543 Grinnell Co., Inc., 1232-12331 . Hammond Brass Works, 1567 Illinois Engineering Co., 1548-1549 Minneapolis-Honeywell Rego*?j2* Co., 1428-1429 ^ Ohio Brass Co., 1556 Saroo Co., Inc., 1558-1559 Warren Webster A Co., 1562-1584 VALVES, Radiator, Pneums^. Diaphragm '3 Johnson Service Co., 1422-1423 -fr Minneapolis-HoneyweU RegulatsT' VALVES. Float Alco Valve Co., 1410 Hubbell Corp., The, 1421 Illinois Engineering Co., 1548-1549 Jenkins Bros., 1568 Ohio Brass Co., 1556 Co., 1428-1429 .Efe Powers Regulator Co., The, 14*23 1436 $ Illinois Engineering Co., 1548-1549 Maid-O'-Mist, Inc., 1550-1551 VALVES, Packless McDonnell A Miller, Inc., 1490-1493 C. A. Dunham Co.. 1541-1543 VALVES. Reducing _ Bell A Gossett Co., 1516-1517 Numerals following Manufacturers' Names refer to pages in the Catalog Data Section aexJMModera Equipment 1167 VALVES, Water Flow Regulat Auer Register Co., The* 1373 ' ' ' fu^feSp&a^iv'^h^Robert- Beinllg"* Gossett Co., 1516-1517 Barber-Colman Co., 1376, 1411 ' DeBothesat Fans Div., American iSKOsSwW-.F*Ju"lton CVontrols Co., 1416"ian?*Specialty Mfg. Corp., _ 'mra'Engiheerihg Co.. 1548-1549 RfcrFS^CnrUsle A Hammond Co., .... DTF7ouml1letoVnaClSvwyellpnChkooa.nn, TTDh^ieivir,.,15TT6Kh5e, Robert shaw-Fulton Controls Co., 1416-- 1417 Hoffman Specialty Mfg. Corp., Mc15D4o4-n1n54e7ll A Miller, Inc., 1490-1493 Powers Regulating Co., The, 1434- Machine A Metals. Inc., 1330 Charles Demuth A Sons, Inc., 1377 General Blower Co., 1332 - Hart A Cooley Mfg. Co., 1380-1381 Hendrick Mfg. Co., I389-13S3 Hunter Fan A Ventilating do., 1334 Ilg Electric' Ventilating Co., 1234. 1335 --^Heaters, Inc., 1519 1 .^A^Thrush A Co., 1520-1521 VALVES. Refrigerant Line --r'Velre Co.. 1410 _ mmohd -Brass Works, 1567 Henry-Valve Co., 1420 Jenkins:Bros., 1568 Worthington Corp., 1192 V&klCorp:, 1193 Mtity 1436 Taco Heaters, Inc., 1519 H. A. Thrush A Co., 1520-1521 VALVES, Water Level, Float Control Maid-O'-Mist. Inc., 1550-1551 McDonnell A Miller, Inc., 1490-1493 VALVES, Water Regulating Alco Valve Co., 1410 - Independent Register Co., The. 1384 1385Knowles Mushroom Ventilator Co., .. Propellair Div., Robbins A Myers, Inc.. 1343 Reed Unit-Fans. Inc., 1344 ' Register & Grille Mfg. Co., Inc., 1389 Titus Mfg. Corp., 1392-1393 Trane Co., The. 1246-1247 United States Register Co.,' 1396 1397 . VALVES, Relief V#D?Andemon Co., The, 1534-1535 "H!"**;G.qBsett Co., 1516-1517 -Eddington Metal Specialty Co., 1505 Henry.Valve Co., 1420 Jas.5r.'Marsh Corp., 1552-1553 A Miller, Inc., 1490-1493 Monarch.Mfg. Works. Inc., 1299 Taco'Heatera. Inc., 1519 Hi'A? Thrush A Co., 1520-1621 Trans Co., The. 1246-1247 York Corp., 1193 Dole Valve Co., 1565 Fulton Sylphon Div., The, Robert- shaw-Fulton Controls do., 1416-- 1417 Hammond Brass Works, 1567 Jenkins Bras., 1568 Jas. P. Marsh Corp., 1552-1553 McDonneU A Miller, Inc., 1490^493 Penn dontrols, Inc., 1432 Powers Regulator Co., The, 1434 1436 Saroo Co., Inc., 1558-1559 Universal Diffuser Corp., 1398 Waterloo Register Co., Inc., 1399 VENTILATORS, Laboratory Gallaher Co., The, 1360 E. H. Sheldon Equipment Co.. 1356-1357 VENTILATORS, Roof Air Control Products, Inc., 1368-1371 Air Devices, Inc., 1261, 1372 Aladdin Heating Corp.,' 1318 VALVES, Safety Frick,Co., 1313 General Controls, 1418-1419 " ry Valve Co., 1420 rvMarsh Corp., 1552-1553 McDonnell A Miller, Inc., 1490-1493 ". : ' VALVES. Solenoid .Aloe Valve Co., 1410 General Controls, 1418-1419 Jm?P. Marsh Cotp., 1552-1553 McDonnell A Miller, Inc., 1490-1493 .Milwaukee Gas Specialty Co., 1430 W.fH. Nicholson A Co., 1554-1555 Penn Controls, Inc., 1432 Bare Co., Inc.. 1558-1559 Spenee Engineering Co., Inc., 1439 ute-Rodgers Electric Co., 1442 YALVES. Stop and Check (See t;,'Volte*,1 Non-Return) VANES, Air Turning Duro-Dyne Corp., 1400 VAPOR BARRIERS Glass Fibers Inc., 1582 Infra Insulation, Inc., 1602 Insul-Mastic Corp. of America, 1584 Silvercote Products, Inc., 1605 VAPOR HEATING SYSTEMS (See Heating Systems, Vapor) VENT FLUE CAPS (See Cape, Vent Flue) VENT PIPE, Gas or Vents, Gas (See Pipe, Gas Vent) VENTILATORS. Attic (See Pane. Allen Ventilator Div., Production Planning Co., 1358 American Blower Corp., 1272-1273 G. C. Breidert Co., 1359 Century Fan A Ventilator Co., 1328 DeBothesat Fans Div., American Machine A Metals, Inc., 1330 Gallaher Co., The, 1360 General Blower Co., 1332 Hartzeli Propeller Fan Co., Div. of Castle Hills Corp., 1333 Hirschman-Pohle do., Inc., 1361 Ilg Electric Ventilating do., 1234, 1335 Iron Lung Ventilator Co., 1362 Muckle Mfg. Co., 1363 ' New York Blower Co., 1341 Penn Ventilator Co., 1364 Propellair Div., Robbins A Myers. Inc., 1343 . Sheldons Engineering Ltd., 1346 Swartwout Co., The, 1365 Trade-Wind Motorfans, Ino., 1350 Trane Co., The, 1246-1247 Electric, Propeller, Supply ana Western Engrg. A Mfg. Co., 1366 .VALVES, Tempering Dole .Valve C6., The 1565 Exhaust) L. J. Wing Mfg. Co., 1249-1251. A-ir C- ontrol Products., Inc.,. 1368-1371 Fulton Sylphon Div' The Robert- American Blower Corp., 1272-1273 ^shaw-Fulton Controls Ho '1417. " Oo-' G. C. Breidert Co., 1359 Philip Carey Mfg. Co., The, 1580 VENTILATORS, Ship Air Devices, Inc., 1281, 1372 ( v -J Regulator Co., The, 1434 '1436 ' ^eo Co.. Inc., 1556-1559 .tsco Heaters, Inc., 1519 fv 1581 Champion Blower A Forge Co., 1327 DeBothezat Fans Div., American Machine A Metals, Inc., 1330 General Blower Co., 1332 G. C. Breidert Co., 1359 Gallaher Co., The, 1360 Hartzeli Propeller Fan Co., Div. of Castle Hills Corps., 1333 Penn Ventilator do., 1364 L. J. Wing Mfg. Co., 1249-1251 VAI-VES, Thermostatic Hirachxnan-Pohle Co., Inc., 1361 Alco.Valve Co., 1410 Hunter Fan A Ventilating Co., 1334 Mrber-Colman Co.. 1376, 1411 Hg Electric Ventilating Co., 1234, SS?* Co-i 1448-1449 -1-3--3-5- , . Sylphon Div., The, Robert- Blower Co.. The. 1338-1339 ^-Fulton Controls do.. 1416- .. 1 Unit-Fans, Inc., 1344 Torrington Mfg. Co., The, 1348-1349 --S?j--*TM--1 CwoUntHroUlUs,| M141io8--1is41iv9 Trade-Wind Motorfans, Inc., 1350 Hoffman Specialty Mfz Coro Western Engrg. & Mfg. Co., 1366 _V1544-1547 ^orp* L.J. Wing Mfg. Co., 1249-1251 VENTILATORS, Unit Air A Refrigeration Carp., 1171 American Blower Corp., 1272-1273 DeBothesat Fans Div., American Machine A Metals, Ine., 1330 General Blower Co., 1332 Hg Electric Ventilating Co., 1234, 1335 Muckle Mfg. Co., 1363 ~ Paired Co., 1548-1549 ' liu. VENTILATORS. Ceiltaa Herman Nelson Div., American Air Filter Co.. Inc., 1242-1243 <1438 " Co'. The. 1434~ ^ ' >S-1558 -rS?" ""Otteenng Co.. Inc., 1439 Inc., 1440 i srnail-Waring Co., 1561 C-.C Trade-Wind Motorfans, Inc.. 1350 VENTILATORS, Floor and Wall Air Control Products, Inc., 1368 1371 John J. Nesbitt, Ino., 1244-1245 Propellair Div., Robbins A Myers, Inc., 1343 Trade-Wind Motorfans, Ine., 1350 Trane Co., The, 1246-1247 L. J. Wing Mfg. Co., 1249-1251 m'Si-: Please mention THE GUIDE 1954 when writing to Advertisers VENTILATORS, Window Airtemp Div., Chrysler Corp., 1196 Air Control Products. Inc., 1368-1371 1197 Hunter Fan A Ventilating Co., 1334 Baltimore Aircoil Co., Inc., 1289 Ilg Electric Ventilating Co., 1234, Binka Mfg. Co., 1290-1291 1335 Brunner Mfg. Co., 1311 Ian Mower Co., The, 1338-1339 Carrier Corn.. 1178-1179 Muckle Mfg. Co., 1363 Curtis Refrigerating Machine. Div. Reed Unit-Fans, Inc.. 1344 of Curtis Mfg. Co., 1312 L. J. Wing Mfg. Co.. 1249-1251 Drayer-Hanson, Inc., 1181 Fluor Corp., Ltd., The, 1292 Halstead A Mitchell, 1294 VIBRATION ABSORBERS OSes Kennard Corp., 1235 Sound Deadening) Lilie-Hoffmann Cooling Towers, American Brass Co., The, 1256-1257 Inc., 1295 Barry Corp., The, 1320 Marley Co., The, 1296 Celotex Corp., The. 1588. Mario Coil Co.. 1314 Ftexonica Corp., Chicago Metal Hose Modine Mfg. Co., 1240-1241 Div., 1258 . National Radiator Co., The, 1452 -Glass Fibers, Inc., 1582 1454 Mundet Cork Corp., 1597 Niagara Blower Co., 1186 Patterson-Kelley Co.. Inc., The, 1307 VIBRATION ISOLATORS J. F. Pritchard A Co., 1297 Barry Corp., The, 1320 Refrigeration Economics Co., Inc., 1248 WALLBOARD ANCHORS AND ADHESIVES Devices, Inc., 1570 Miracle Adhesives Corp., 1570 Santa Fe Tank. A Tower Co., 1298 Serve!, Inc., 1204-1205 Trane Co., The, 124^1247 Westingbouse Electric Corp., Air Conditioning Div., 1191 Worthington Corp., 1192 WALLBOARD, Insulating Yarnall-Waring Co., 1561 Armstrong Cork Co., 1587 Philip Carey Mfg. Co., The, 1580 York Corp., 1193 Young Radiator Co.. 1251 1581 Celotex Corp., Tne, 1588 Insulite. 1590-1591 Johns-Manville, 1592-1593 Mundet Cork Corp., 1597 Wood Conversion Co., 1600 WATER COOLING, Spray Sya- terns . Air A Refrigeration Corp., 1171 April Showers, Co-, Inc., 1569 Carrier Corp., 1178-1179 McQuay, Inc., 1236-1237 WARM AIR FURNACES Furnaces, Warm Air) (See Niagara Blower Co., 1186 Pittsburgn Lectrodryer Corp., 1187 Refrigeration Engineering, Inc., 1316 Trane Co., The, 1246-1247 WARM AIR HEATING SYSTEM Westinghouse Electric Corp., Air (See Beating Systems, Furnace) Conditioning Div., 1191 York Corp., 1193 WASHERS, Air (See Air Washers) WATER COOLING (See Cooling Equipment, Water; Cooling Towers) Acme Industries, Inc., 1300 Aerofin Corp.. 1301-1303 WATER COOLING TOWERS (See Cooling Towers, Water) WATER FEEDERS (See Feeders, Boiler Water) WATER MIXERS, Thermos (See Valve*. T*mn^r%ng^ - Bell A Gossett Co.Vi516-l517Dole Valve Co., The, 1565 i Fulton Sylphon Div., The, Ro' shaw-Fulton Controls Co..:141 1417 % Powers Regulator Co., Thelll 1436 ' Sarco Co., Inc., 1558-1559 Taco Heaters, Inc., 1519 WATER TREATMENT Worthington Corp., 1192 WELDING FITTINGS (Si tings, Welding) ' WELDING ROD ,, American Brass Co., The. 125&-I Revere Copper A Brass, Inc., 1" WHEELS, Blower . j|v Brookside Products Co., Inc.,- J" Brundage Co., The. 1324 ' Champion Blower A Forge Co.;! Clarage Fan Co., 1180, 1329 ~ General Blower Co., 1332 Lau Blower Co., The, 1338-1339 Morrison Products, Inc.. 1340 Revcor, 1345 S. Torrington Mfg. Co., The, 134tl United States Air Conditio^ Corp., 1190 Viking Air Conditioning Corp.?. WHEELS, Spray (See Spray Egui ment) .* $ WINDOWS. Fire Observation Detroit Stoker Co., 1488 WINDOWS, Storm Ingersoll Products Div., Barg Warner Corp., 1603 MANUFACTURERS' CATALOG DATA (PAGES 1171-1616) Numerals following Manufacturers' Names refer to pages in the Catalog Data Section On pages 1171-1616 will be found the Catalog Data of 319 manufacturers whose products are described and illustrated. For the convenience of the user of THE GUIDE 1954 there are eight main divisions: Air Conditioning ................................................. 1171-1255 Air Conditioning and Heating Piping........... 1256-1260 Air System Equipment............... 1261-1401 Bends. Coils. Fittings.........................................1402-1409 Controls and Instruments.................... 1410-1442 Heating Systems..................................................1443-1568 Insulation...............................................................1569-1605 Publications........................................................... 1606-1612 On pages 1141-1168, under each of the index headings--Air Cleaning Equipment, Fans, Hu midifiers, Ventilators, etc., will be found a list of manufacturers of any desired products, fully cross-indexed, and the page numbers in the Catalog Data Section where the products are described. By reference to these indices, the manufacturers' names and the page numbers, any item of equipment or materials, and the producer's address, may be located quickly. Air Conditioning Central. Systems Air & Refrigeration Corporation ' 439 Madison Avenue, New York 22, N. Y. 271 Milton Avenue, S. E., Atlanta, Ga. Representatives in all major cities Air Conditioning, Humidifying, Dehumidifylng, Cooling, Scrubbing, Air Washing and Purification Apparatus Air & Refrigeration Corporation specializes in the design and manufacture of indus trial and comfort-conditioning apparatus where maintenance of suitable humidity and temperature within closely controllable limits is essential. This specialization is based on technical knowledge and ingenuity born of extensive experience in the solution of the more difficult problems of air conditioning. A complete line of air conditioning equipment is available to contractors and owners for all phases of humidifying, dehumidifying, cooling and washing. * Capillary Air Washers provide a superior type humidifying, dehumidifying, air washing, cleaning and cooling unit for central station apparatus. For most purposes the Capillary Washer requires the volume of water at the pressure used by conventional spray equipment. They are available with factory insulated casings ana tank for central station applica tions. For complete data, see Capillary Bulletin. * Capillary Unit Conditioners are factory insulated and as sembled, ready for use. They include fan, motor, drive, heating coils, Capillary Cells with suitable sprays, spray pump and mixing dampers. Units are designed for floor mounting or for ceiling suspension, and can be arranged for the reception of Factory insulated Class I cooling coils, if required. Complete description and engineering Caphlary Air Washer data will be found in Capillary Unit Bulletin. Spray Type Air Washers for washing, humidifying and dehumidifying air are all basically the same. A & R Spray Washers include special features of design developed to insure more efficient and dependable operation, lower maintenance costs, and, in many cases, lower installation costs. Such features relate especially to eliminators, collecting tanks, flooded baffles, nozzle arrangement, etc. Spray Washers can be supplied with factory insulated casings and tank for central station applications. For details, see Air Washer Bulletin. Sprayed Coil Dehumidifiers for year-round treatment of air are complete with cooling coils, sprays, circulating pump and glass mat eliminators. Sprayed coil de^Jiumidifiers are factory insulated and complete, ready for assembly in the field. "" Special features in design insure continuous washing and cleaning of finned surfaces and easy accessibility to all parts. For engineering information and detailed descrip tion, see Sprayed Coil Bulletin. A & R Insulated Panels consist of insulation between metal sheet on one side and hard fiber board on the other, the three laminated and cemented together. This unique panel design includes the structural frame to form units which require only boiling together to make enclosures of any required shape for plenum chambers and many other purposes. Panels are available in widths from 3 in. to 48 in., and in lengths /? ^eir use insures tremendous economies in field labor. For details, see Panel Bulletin. Write for catalog and engineering data. Registered Trade Mark Type gs Air Washer Factory Insulated 1171 Factory Insulated Plenum Chamber Air Conditioning Central System American Blower Corporation Detroit 32, Michigan CANADIAN SIROCCO COMPANY, LTD, 310 Ellis Street, Windsor, Ontario Branch Offices in Principal Cities Division of American Radiator & Standard Sanitary Corporation AIR CONDITIONING -- HUMIDIFYING -- DEHUMIDIFYING -- COOLING -- VENTILATING -- HEATING -- VAPOR-ABSORPTION -- DRYING -- AIR WASHING AND PURIFICATION -- EXHAUSTING EQUIPMENT AND MECHANICAL DRAFT APPARATUS American Blower Corporation Air Conditioning ""items TYPES OF AMERICAN BLOWER CORPORATION AIR HANDLING AND CONDITIONING EQUIPMENT All types of air handling and air conditioning equipment for industrial applica tions, process work, drying, cooling; also equipment for stores, offices, shops, public buildings, power plants, etc., and attic and kitchen ventilation for homes. Capillary Air Washers--above, for high efficiency in cleaning, humidification, cooling and dehumidification of air. Air is forced at low resistance through long, irregular passages of small size formed by a large amount of thoroughly wetted glass surface. Write for Bulletin 4023. "ABC" Utility Sets--complete packaged units, directly connected or V-bclfc short coupled drive for duct applications. Equipped with Aileron Control consist ing of scroll sheet adjusted by connecting rod. Fan outlet is modified to give effi cient operation over a wide range of air volumes and pressures. Sizes for a wide variety of ventilating problems. Quiet, compact. Complete technical informa tion in Bulletin 2814- Heating & Cooling Coils--right, Ameri can Blower heating and cooling coils offer a number of improvements in design and construction. Available in a complete range of sizes and types, including: Bulletin B-1218 Type S steam coils Type D double tube coils Type U return blend coils Type B booster coils Bulletin 1521 Type W water coils Type C cleanable water coils Type X direct expan sion coils Bulletin B-1318 Type H heavy duty coils Double Inlet "ABC" Multiblade Fan above, is a heavy duty ventilating f*n* The wheel has narrow, forward pitched blades. Low tip speeds assure quiet op eration. Request Bulletin A-801. But' letin A-608. describes backwardly in* dined, nonoverloading HS Fan. 1172 Unit Heaters--for many general purpose heating jobs. Wall or ceiling mounted. Streamline construction, rugged heating elements. Steam or hot water. Re quest Bulletin 6717. Heating and Ventilating Units--with air filters and Aileron control. Ideal wher ever attractive, quiet and economical heating and ventilation units are re quired. Wall, floor or ceiling mounting. Offer great flexibility of design and ar rangement to meet specific needs. Bul letin 7227. Gas Fired Unit Heater--self con\fiined--available in 7 sizes for clean, -'''pufcomatic, instantaneous heating. Ad justable louvers assure efficient heat dis tribution throughout the work area. A. G. A. approved. Write for Bulletin Centrifugal Type Unit Heaters--for itn or without duct systems, for h ard to heat areas. Ideal for mounting. Request Bulletin 7727. American Blower Air Conditioning Units. --Type A for all normal unitary type commercial and industrial applications. Cooling, heating, humidifying. Capaci ties 1000 cfm--40,000 cfm. Type S for commercial and industrial applications desiring washed air or high relative hu midities. Capacities 1000 cfm--36,500 cfm. Type M, large capacity for central system installation with separately mounted fan. Cooling, dehumidifica tion, heating, humidifying. Capacities 1000 cfm--41000 cfm. Bulletin 7487. 1173 A. i.r C^ ond..i.t.ioni.ng Central Systems Humidification and Cooling American Moistening Company Atlanta, Ga. Providence 1, R. I. Boston, Mass. Camden, N. J. Charlotte, N. C Air Conditioning Systems Since 1888 Humidification Evaporative Cooling (Ductless or Central Station) Refrigeration Because Amco installs both ductless and duct systems, you can rely on Amco engi neers to give you sound, impartial advicje. If you already have a modern, efficient humidification system and desire COOLING, an Amco engineer will probably point out the advantages of an Amco ductless system in which you discard nothing and make only a modest addition to your present humidification system. On the other hand, if your proposed installation calls for a unit duct or a central station air condi tioning system, Amco can handle the job. In either case you will get reliable, un biased advice and expert installation of a system tailored to your needs. A few of the many AMCO products with a Long Record of Dependable Performance Self-cleaning Atomizers; Humidity Controls; Amtex Humidifiers; Evaporative Cool ing Units; Mine Sprays; Fabric and Paper Dampeners; Electro Psychrometers; Sling Psychrometers; Hygrometers; Atometer. AMCO ATOMIZER, NO. 6 New Automatically Self-Cleaning AMCO No. 6 atomizer retains all the time-tested features of the popular No. 5 unit . .. . plus additional features which assure improved spray quality. Its bet ter performance and ease of maintenance make this automatically self-cleaning atomizer superior for new installations and replacements. AMCO HUMIDITY CONTROL Compressed Air Operated A unique hygroscopic element, which responds primarily to humidity and not to temperature, forms tne heart and brain of the Amco Humidity Control. Its sensitive impulses, ampli fied by a simple pneumatic circuit, respond automatically to changes in relative humidity of one or two per cent of the de sired value, with a minimum of care and supervision. Suc cessful operation in many hundreds of mills throughout the United States attests to its ruggedness and reliability. AMCO EVAPORATIVE COOLING UNIT The Amco System of evaporative cooling contributes to smooth .production at high speeds in two ways; it maintains the percentage of relative humidity best suited to the fibre and process involved, and at the same time promotes the com fort and efficiency of personnel by ob taining the maximum practical cooling effect from evaporation. It does this by introducing outside air into the room in Varying amounts, regulated in accord ance with climatic conditions and inside requirements. A ductless system--very flexible and portable. Can be applied in conjunction with an existing humidifying system. 1174 Air Conditioning BUEN50D STACEY^ mcofteoniTCb 221 Watson Building 60 East 42 St. 1001 N. Church St. Greensboro, N. C. New York 17, N. Y. Charlotte 1, N. C. Air Conditioning, Humidifying, Cooling, Ventilation Systems BUENSOD-STACEY AIR CONDITIONING SYSTEMS are based on long experience and great technical knowledge. Where close control of temperature and relative humidity is essential, the Buensod-Stacey engineering and contracting organiza tion designs and installs systems to meet the most exacting requirements with the greatest economy. To facilitate the installation of systems for air conditioning, refrigeration, ventilation, etc. Buensod-Stacey maintains two factories, one in Charlotte, N. C. and the other in New York, N. Y., with complete sheet metal and pipe shops in each. Buensod-Stacey also manufactures many components of the complete system, a few of which are listed below: BUENSOD-STACEY HUMIDIFIERS AND DEHUMIDIFIERS incorporate many unique features to increase effi ciency and decrease maintenance. Fac tory insulation reduces field labor expense. Special eliminators and spray systems insure proper performance for each application. All air washers are treated with protective coatings to reduce corrosive action. Buensod-Stacey Special Dehumidifier BUENSOD-STACEY EVAPORATIVE COOLING UNITS have all the advan tages of central station systems but are so designed that they can be suspended from the ceiling and, thus, save valuable floor space. They can be used to supple ment and enlarge existing systems with out disturbing their continuous opera tion. Buensod-Stacey Evaporative Cooling Unit AGASY ROTARY STRAIN*xto save maintenance dollars. Con structed of stainless steel, they are es P ially useful where the air contains e Q,uanUties of solids such as lint ln textile mills. Buensod-Stacey Rotary Strainer mui,?^OD-STACEY DUAL DUCT SYSTEM* for air conditioning multi-story and trolled^001 kuildinRS }8 a practical and economical way to obtain individually conlaborat .mPera^ures in each enclosed space of such structures as office buildings, tion ofK^k' aPar*ment' bouses and hotels. This system, which is a simple combinaat rW j " Pressure. high velocity, cold and warm air ducts, distributes the air tribut'lred temperature through Buensod-Stacey Vertical and Horizontal Air Dis- 1Q.& an<* Mixing Units. It does not require widely scattered coils, fans or other mechanical apparatus. rtected by patent applications. 1175 Air Conditioning central Sjstems EN_G_IN__E_E_R_S__A_N_D MANUFACTURERS Winston-Salem, N. C HUMIDIFYING -- VENTILATING -- COOLING -- FILTERING COMPLETE SYSTEMS 1. CENTRISPRAY--A Unit or Central Station System, developed by The Bahnson Company, using the truly modu lating Centnspray Air Washer. Based on the first really new idea in Air Washer design in almost fifty years, the Centrispray System provides precise control of temperature and humidity with out standing flexibility in design and opera tion. 2. HUMEDUCT--A unit system for eco nomical industrial air conditioning. Sin gle or multiple installation--for buildings of any size. Systems provide ventilating, heating, cooling, humidifying, dehumidifying and filtering in any desired com bination. 3. CENTRAL STATION--Central Sta tion Systems for industrial and com mercial applications are designed and manufactured by The Bahnson Com pany. Type Y or Type DC Air Washers along with Bahnson-manufactured com ponents provide temperature and hu midity control. Bahnson has manufac tured many of the largest Central Station Systems in existence today. UNIT HUMIDIFIERS 4. TYPE E HUMIDIFIER--A self-con tained unit with high evaporative capac ity for installation in all types of indus trial and commercial spaces requiring automatically controlled humidification. Evaporates up to 3 gallons per hour with 360 degree radial distribution of mois ture. Requires only water supply and electrical connection. 5. CENTRIFUGAL HUMIDIFIER--A self-contained unit for industrial humidi fication. Evaporation up to 12.gph plus directional air flow with fractional horsepower motor. Installed singly or in groups with individual or group auto matic control. Requires only water supply, drain, and electrical connection. 6. TYPE BA-2 HUMIDIFIER--A highcapacity unit for overhead suspension in commercial and industrial applica tions. Adjustable grilles give complete directional control of moist air delivered. Automatically regulated, the unit pro vides air flow, humidification and filter ing. Requires only water supply, dram, and electrical connection; capacity up to 18 gph. 1176 Air Conditioning Central Systems Winston-Salem, N. C HEATING -- DEHUMIDIFYING -- AIR CLEANING -- VAPOR ABSORPTION SYSTEM COMPONENTS 7. TYPE S AIR CLEANER--An auto matic self-cleaning filter for systems handling air which contains heavy con centrations of lint. Eliminates routine cleaning of recirculated air screens and requires no replacement of filter media. 8. AIR WASHER--Bahnson Type Y and Type DC Air Washers cleanse, cool, and provide humidity control. Available in standard sizes from 6,000 to 250,000 cfm, they can be provided with spray systems best suited for the specific ap plication. 9. AUTOMATIC SUCTION STRAINER --The Type B Automatic Suction Strainer is a self-cleaning rotary strainer for Air Washers. Prevents clogging of spray nozzles and allows washer to oper ate at full efficiency. Can be fitted to new or existing systems; fully automatic in operation. 10. TYPE DC SPRAY NOZZLE--The Bahnson Type DC Spray Nozzle utilizes the principle of impingement of water jets to produce a fine uniform spray. jLhiS' can result in a saving in pumping cost of 50 per cent over conventional air washer spray nozzle systems. 11. TYPE ESC ATOMIZER--A self cleaning pneumatic atomizer of superior design for direct humidification or sup plementary evaporation. Uses both air and water under pressure to provide high evaporation and fine spray quality at low cost. Modulating control regulates evap oration in direct proportion to the room requirements. t'-vuumwc or eiectnc Humidity and ^u,re cont-rols are sensitive, accu4Pendable. Available in as P ed cabinets with recorders installed. -- Bahnson wide-blade tinn.i a * r!^es Prov'de complete direcinr,,,,contrl f air flow. Special features cleaninga remvable core *0 facilitate the Hi.? We" as t provide access to tne distribution duct. . 1177 ' Air Conditioning Carrier Corporation Syracuse 1, N. Y. MARINE DIVISION: 385 Madison A to. New York 17. N. Y. Carrier INTERNATIONAL DIVISION 385 Madison Are. New York 17. N. Y. Offices and Dealers in principal cities--refer to your telephone directory. AIR CONDITIONING Room Air Conditioners--for individual rooms and offices in compact modern styl ing and handsome finish to blend with fin est of interior furnishings. Window sill models in 3*3, Vl, % and 1 hp capacity. Console models in 1 and hp capacity. Weathermakers--completely self-con tained air conditioners for commercial and industrial applications. Seven sizes from 2 to 20 hp cooling capacity. Year-Round Weathermakers--for heat ing and cooling in residential and com mercial applications. Compact, efficient gas heating combined with summer cool ing. Six combination sizes. Zoning Weathermakers--blow-through fan-coil units for air conditioning sys tems using remote sources of heat and refrigeration. Six sizes for comfort and industrial applications, 6 to 80 tons. System Weathermakers--fan-coil uni tary air conditioners for application to central cooling and heating systems for comfort and industrial use. Seven basic sizes in vertical and horizontal models. Central Station Air Conditioners--for application with fan and duct systems for large spaces such as stores, theatres, auditoriums and industrial plants. Weathermaster Systems--for air condi tioning of multi-story, multi-room build ings such as hotels, hospitals, office and apartment buildings. System consists of room units with individual tempera ture control, and central station air conditioning. Conditioned air distrib uted by high velocity conduits to indi vidual Weathermaster units shown. Blast Freezers and Cold Diffusers--for food freezing and storage, meat packing operations, and other industries requir ing low temperatures. Units available in suspension or floor models, for use within space to be refrigerated or re motely located and connected by ducts. Write for descriptive literature. 3178 Carrier Corporation Centrifugal Refrigerating Machines--for large comfort and industrial air condi tioning applications and for process cool ing. High efficiency at peak or partial loads. Operate with any standard motor or turbine drive. Available in capacities up to 3000 tons in a single unit. Absorption Refrigerating Machines--for producing chilled water at 38 F or higher in fully automatic operation from 10 to 100 per cent capacity. Uses high or low pressure steam for operation. Capacities 115, 150, 200, 270, 350, 500, and 700 tons. Reciprocating Refrigerating Machines-- for comfort and industrial air condition ing and for process cooling. Direct or belt drive, water or evaporative cooled types, 100 to 200 tons capacity. Commercial Refrigerating Machines-- for storage refrigerators, display cases, walk-in coolers and similar duty. Com plete with compressor, drive, air or water cooled condenser and controls. All sizes. Reciprocating Compressors--for refrig eration needs of air conditioning and process cooling. Adaptable to all drives and available for "Freon" and ammonia refrigerants. Sizes from 3 to 200 hp. Evaporative Condensers--for use with refrigerating compressors in place of water cooled condensers. Simplify water supply and disposal problems. For in door or outdoor use. Capacities 10 to 85 tons, for "Freon" or ammonia. Air Conditioning Central Systems REFRIGERATION Carrier) INDUSTRIAL HEATING Unit Heaters--for commercial and indus trial space heating using steam or hot ^ater. Complete range of sizes in two types: Model 46U Horizontal Discharge m capacities from 21,000 to 200,000 Btu per hour, and Model 46S Four-way Di- *n caP*cities from 49,000 to 90,000 Btu per hour at 2 lb steam. Gas-Fired Unit Heaters--for clean, eco nomical heat in offices, stores, factories a{Jp similar spaces where gas is avail able. Approved for manufactured, mixed, and LP gases. Capacities: 50,000 to 230,000 Btu per hour. Heat Diffusers--for ventilating as well s heating large commercial and indusriai spaces. Floor, wall or ceiling ounted with coils for steam or hot fter- Capacities 115,000 to 2,390,000 tftu per hour at 2 lb steam. 1179 Air Conditioning s"temS Clarage Fan Company Kalamazoo, Michigan Application Engineering Offices In Principal American Cities (Consult Telephone Directory) Clarage Air Handling and Conditioning Equipment For nearly a half century Clarage has been a leading manufacturer of equipment and units for ventilating, exhausting, cooling, air cleaning, humidifying and com plete conditioning. Clarage equipment is designed to meet all types of industrial, commercial and public building requirements. For other equipment in the complete Clarage line see "Air System Equipment--Fans and Blowers." Clarage Multitherms cool and dehu- midify in summer, heat and humidify in winter. For comfort applications and process conditioning. Vertical and hori zontal types, 10 sizes, capacities 600 to 20,500 cfm. . Clarage Air Washers are built in both capillary and spray types. Sizes range from 2000 to 193,000 cfm. Used for air cleaning, humidifying and dehumidifying purposes. Special constructions can be furnished. Clarage Unicoil Units are ideal as an integral part of a central station system for heating or cooling, or both; or for complete air conditioning in comfort applications. Wide size range. We welcome your inquiry on any air handling or conditioning problem. Con tact our nearest branch office, or write us at Kalamazoo, Michigan. 1180 Ah Conditioning . omflJaSL hanson SINCE 1910 Factory and General Sales Office Medford St. Los Angeles 63, California Representatives in Principal Cities Manufacturers of Air Conditioning and Refrigeration Equipment REFRIGERATION AND AIR CONDITIONING LEFT HAND COLUMN READING DOWN: Flexazone Type FZ--air conditioners of the blow-through type for supplying several zones independently by damper control in either horizontal or vertical types. Perma-Fan Series PF--a complete line of evaporative condensers of the blow-through type based on DrayerHanson experience acquired since build ing the first unit in 1937. Capacities range from 5 to 65 tons. WMT Cooling Towers--in wide range of sizes. Designed for air conditioning and refrigeration use. HH and HHV types--air conditioners for both horizontal and vertical air con ditioning as used in central type systems. RIGHT HAND COLUMN READING, DOWN: Spotaire Series HRC--room unit air conditioner for chilled water, hot water or direct expansion. For concealed in stallation. Also furnished with cabinet. "Quiet beyond belief!" . Spotaire Series VRC--compactly de signed for floor mounting. Utilizes chilled water, hot water or freon. Fur nished in several sizes. d-h Hot Shot Electric Defrost-- ceiling type unit designed and developed under Drayer-Hanson electric auto matic defrost patents. d-h Spasaver--available in many sizes. Product cooling application for tem perature above 34F. Extended Surface Coils--staggered tubes for steam, water and direct expan sion, freon or ammonia. Also removable header coils and removable plug type coils. 1181 Air Conditioning Central Systems GENERAL ELECTRIC ' HEATING AND AIR CONDITIONING Air Conditioning Division, 5 Lawrence St., Bloomfield, New Jersey REGIONAL SALES OFFICES: New York 22, N. Y.--570 Lexington Ave. Chicago 54, III.--Merchandise Mart, Room 1144 New Orleans 12, La.--511 International Trade Mart Los Angeles 17, Cal.--1052 West 6 Street See your classified telephone directory for local sources under: G-E Home Heating & Cooling Equipment G-E Air Conditioning--G-E Water Coolers G-E HOME HEATING AND COOLING EQUIPMENT 1. G-E YEAR-ROUND AIR CONDITIONER Self-contained central system heats, cools, filters, dehumidifies, ventilates, and circulates conditioned air quietly and effec tively^ Cooling capacity: 1%, 2, 3 ana 5 tons.Heating capacity: with gas firing, 60, 75, 90, 120, 150, and 210,000 Btuh input; with oil firings, 60, 85, 115, and 155,000 Btuh, bonnet output. Over 220 heating-cooling combinations. For all new homes, and existing homes with warm-air systems. Upflow, Downflow, Horizontal models--water-cooled and air-cooled. 2. G-E HOME COOLING UNIT FOR ENTIRE HOME Available in 1}$, 2, 2>, 3 and 5-ton capacities, this self-con tained unit will cool every room of the home . . . filter, de: humidify, ventilate, circulate. "Pre-Paired" to match G-E Furnace, it may also be added to warm-air distribution systems and used in homes with wet-heat systems (See #3 below). G-E refrigeration compressor has five-year Warranty. Up-' flow, Downflow,Horizontal models--water-cooled and air-cooled. Single and three-phase motors. 3. G-E AIR-WALL* SYSTEM FOR HEATING AND COOLING The original perimeter distribution system features Air-Wall registers that spread a protective wall of conditioned air over insides of windows and outer walls, protecting against extremes of nature winter and summer. Working with same ducts and G-E Home Cooling Unit, these Air-Wall registers blanket the walls with cool air that diffuses evenly with room air for greater summer comfort, without cold air puddling on floors. With G-E Year-Round Air Conditioner, or G-E Furnace or G-E Home Cooling Unit, same registers deliver both heat and cooling. Standard, Baseboard and Automatic Air-Wall regis ters (latter with individual room temperature control) permit complete decorating freedom, eliminate carpet-cutting. 4. G-E OIL-FIRED WARM AIR FURNACES Famous for fuel savings up to 50 per cent, according to actual users. Features: G-E Atomized Oil burning method, famous G-E "Turnback Flame" tailored to combustion chamber, and G-E finned "Spira-Flow" heat transfer surface, made of steel. Compact, quiet. Factory-wired, assembled and tested. Listed by Underwriters' Laboratories. Four Upflow models: 60, 85, 115 and 155,000 Btuh, bonnet output. "Pre-Paired" for home cooling. Two Downflow models, for basementless homes: 60 and 85,000 Btuh, bonnet output. Two Horizontal models for attic, crawl-space or overhead in stallation: 60 and 85,000 Btuh, bonnet output. 1182 General Electric Air Conditioning gSems 5. G-E GAS-FIRED WARM AIR FURNACES . G.E.'s long-life, cast-iron "Pinpoint" heat transfer sections expose more surface to burning gases, turbulate them for faster, better heating action. Whisper-quiet, space-saving. Factory- wired, tested and assembled. Listed by Underwriters* Labora tories, tested and approved by A.G.A. Six Upflow models: 60, 75, 90, 120, 150 and 210,000 Btuh input. "Pre-Paired" for Home Cooling. Four Downflow models for basementless homes: 60, 75, 90 and 120,000 Btuh input. Three Horizontal models for attic, crawl-space or overhead in stallation: 60, 75, and 90,000 Btuh input. All models are available equipped to burn manufactured, mixed, natural, natural-SUR and LP gases, as specified on . order. a. G-E OIL-FIRED BOILERS Compact, integrated steel boiler units designed exclusively for low-pressure oil burning. Ideal for multiple installation. High heat transfer rate with Tow water content and low metal mass. Built-in tank or tankless-type hot water coil. Five models: 100, 140, 200, 300 and 450,000 Btuh output. Listed by Under writers' Laboratories, Inc. Constructed in accordance with ASME Code. G-E KITCHEN WHITE OIL BOILER is a compact, fully inte grated hot water steel boiler for kitchen or basement. Built-in expansion chamber and tankless-type hot water coil. Designed for radiant panel and forced hot water systems. Attractive white jacket stays comfortably cool. 100,000 Btuh output. Listed by Underwriters' Laboratories, Inc. . 7. G-E GAS-FIRED BOILERS Water-filled, diamond-shaped projections on durable cast iron sections plus zigzag flue gas travel assure rapid heat transfer and maximum heat absorption. Clean, quiet, complete combus tion with raised-port atmospheric burners. Seven models--96. 144, 192, 240, 288, 336, and 432,000 Btuh input for natural, manufactured or mixed gas. Tested and approved by A.G.A. Listed by Underwriters' Laboratories, Inc. Constructed in ac cordance with ASME Code. G-E COMMERCIAL AND INDUSTRIAL AIR CONDITIONING 8. G-E PACKAGED AIR CONDITIONERS--For stores, offices, hotels, restaurants, industrial areas. Factory built, assembled and tested units that cool, dehumidify, filter, venti late and circulate air (heating coil available as accessory). Features new sealed-in-steel, hermetic condensing unit for maximum reliability. Improved Muggy Weather Control dehumidifies without overchilling. Five sizes--3, 5, 7^, 10, 15 and 20 hp^-are ideally suited for multiple installations in large space applications. G-E 5-year Protection Plan on entire refrigeration system at no extra cost. i G-E WEATHERTRON (HEAT PUMP) 9. G-E WEATHERTRON YEAR-ROUND SYSTEMS-- Operating on the heat pump principle, G-E Weathertron cools without water, heats without fuel. A single, self-contained, packaged unit, factory assembled and tested. All-electric and all-automatic, the G-E Weathertron burns no fuel, needs no water or cooling tower yet cools, heats, dehumidifies, filters and circulates air all year round. Set the thermostat once and the Weathertron automatically changes over from heating to cooling and back, not only from season to season but even daily or hourly as required by outside weather conditions. Present markets are principally in the south, southwest and on the west coast; other locations to be added as distribution and service facilities are established. Particularly effective with the G-E Air-Wall System, the G-E Weathertron is avail able in two sizes--3 and 5 hp--for commercial applications as well as residential use. * Beg. trademark of General Electric Company 1183 Air Conditioning Central Systems Frigidaire Division of General Motors Dayton 1, Ohio Room Conditioners--Self-Contained Conditioners-- Year 'Round Conditioners--Compressors Sdf-Con tain ed Conditioner Room Conditioner Self-Contained Conditioners 3, 5, and 7 ton capacity self-contained units. Quickly in stalled, efficient, low-cost cooling. Little or no duct work needed. Use singly, or in multiple for a wide range of applica tions. Attractive cabinets with welded, steel frames. Centrif ugal, double-width fans. Thermostatically controlled. Sealed, direct-drive compressor. Fans and compressor mounted on vibration absorbers for quiet operation. Uses safe Freon-12. Heating coil optional. Five year warranty on sealed compressor. Room Conditioners Four compact, easily installed units, in % and 1 hp sizes, providing all summer air conditioning functions. 4-way cool air outlet, fresh air control, exhaust air control, moisture disposal. All-steel, heavy gage welded cabinet, bonderized. Quiet opera tion. Powered by sealed-rotary Meter-Miser, with 5-year warranty. Selective cooling feature on larger capacity models permits continued dehumidification and air circulation with reduced operating cost in moderate weather. Year-Round Conditioners Year-Round Air Conditioners New combination unit heats in winter, cools in summer for true, one-temperature living. The summer half of this year- round conditioner cools, filters, ventilates, dehumidifies and circulates the air. Exclusive Frigidaire Multipath cooling unit, with counterflow principle, has extra large coil surfaces and fins for maximum efficiency. Entire system is factory-balanced with Frigidaire XX) Meter-Miser compressor for maximum economy. Simple thermostat and damper control. Winter heating unit available for oil, or natural, manufactured and artificial gas. Use of common ductwork for both heating and cooling units makes installation simple in new homes, or in older homes where forced air system was previously installed. Sturdy all-steel cabinet finished in attractive grey enamel. Entire unit warranted for one year--Meter-Miser compressor warranted for 5 years. - XD Meter-Miser Compressors Compressors XD Meter-Miser sealed type compressors, air-cooled models-- to 3 hp; water-cooled models--14 to 7J4 hp; combination air and water-cooled--}4 to 3 hp. Evaporative models--1 n t0 7}<j hp. Also heavy-duty water-cooled and evaporative type compressors--10 to 25 hp, with step-control for regulating capacity. 1184 Air Conditioning % SSaSSSa Coolers . Hastings Air Conditioning Co., Inc. Hastings, Nebr. Manufacturers of Ceding, Heating and Ventilating Equipment. Gas and Steam Unit Heaters, Water, DX and Steam Coils. "Heatwell" Gas Power Conversion Burners. Dealers and Representatives in Principal Cities A Complete Line of Air Conditioners for.DX, Cold City Water, Chilled or Well Water Operation. ` Coils are designed for utmost efficiency and constructed of copper tubing expanded and metallically bonded to pure copper fins. FLOWMETERS (to visually indicate water-flow) are standard on all water equipment. HOME AIR CONDITIONERS--From 2 to 5 tons capacity. Water Coil Models--6 row all copper coils. DX Models--4 row all copper Freon coils. Combination Models--4 row water and 2 row Freon coils'. GAS UNIT HEATERS.--Twelve models, 75,000 to 200,000 Btu capacity. Equipped with CENTRIFUGAL or PRO PELLER type fans. AGA approved for all gases. Stainless steel ribbon burners result in quietj efficient com bustion. Aluminized steel heat exchangers. Dual directional, individually adjustable louvers permit complete control of air delivery. HEATWELL POWER GAS CONVERSION BURNERS-- Adjuslo "V"--Commercial and industrial. Up to 4,000,000 Btu. No combustion chamber required. Adjustable flame placement. Inshot--For oil burner conversions. Up to 300,000 Btu. Roundhead--For coal or oil conversions. Up to 250,000 Btu. Write for Catalogs, Literature, or Information Air Conditioning System Niagara Blower Company General Sales Office: 405 Lexington Aye. New York 17, N.Y. Chicago--5: 37 W. Van Buren St. Buffalo-- 7: 673 Ontario St. " Seattle?:--4: 305 Lowm&a Bldg. District Engineers is Principal Cities of U. S. and Canada Over 85 Years* Experience in Industrial Air Conditioning, Liquid Cooling and Air Drying . NIAGARA AIR CONDITIONING SYSTEMS For human comfort and for all industrial applications requiring controlled conditions Of temperature, relative humidity, air purity and air movement. NIAGARA AIR CONDITIONER, TYPE A, AND CONTROLLED HUMIDITY METHOD USING HYGROL LIQUID ABSORBENT High precision apparatus using saturation to obtain control of R. H. to 1 per cent for laboratory work and control of hygroscopic materials. Ask for Bulletin 122. NIAGARA AIR CONDITIONER, TYPE C A year around air conditioning unit providing heating and humidifying or dehumidi- fying. Ask for Bulletin 80. NIAGARA FAN COOLER AND DISK FAN COOLER For comfort cooling, process cooling, low temperature storage for dairies, fruits, meats, food products, fur storage vaults, etc. Bulletin 72. NIAGARA SPRAY COOLER For all cooling applications requiring high humidity or high capacity in small space. Ask for Bulletin 110. NIAGARA "NO FROST*/ SYSTEM Using Niagara "No Frost" Liquid in spray coolers, prevents frosting of cooling coils, automatically keeps spray solution at proper concentration, gives freedom from brine troubles, corrosion. Constant, efficient operation. Temperature to --100 F- Ask for Bulletin 105 (Food) or Bulletin 95 (Industrial). NIAGARA AEROPASS CONDENSER (Illustrated) Saves power and water cost utilizing atmospheric air to remove heat of condensation- patented Duo-Pass prevents scaling, saves power. "OILOUT" positively removes oil and dirt from refrigerant lines, assuring always full capacity. Balanced Wet Bulb Control assures operation of refrigeration plant at minimum head pressure regardless of weather or load conditions. Capacities up to 400 tons refrigeration. Ask for Bulletins 108 and 111. ' NIAGARA "DUAL** COOLERS Simultaneously cools a room and furnishes chilled water as a refrigerant. Saves equipment cost, operating expense. Patented. Ask for Bulletins 70. NIAGARA AERO HEAT EXCHANGER For cooling industrial liquids, water, oils, solutions, chemicals, compressed air and gases, with Niagara "Balanced Wet-Bulb" temperature control to improve efficiency and obtain precise results. Patented (U. S. Nos. 2,296,946 and R. I. 22,553). Ask for Bulletin 120. NIAGARA INDUSTRIAL LIQUID COOLER Furnishes refrigerated water or aqueous solution in any quan tity up to 220 gpm. Positive control of temperature regardless of load variation. Delivers "sweet" water at 33 F without danger of freezing damage. Ask for Bulletin 104. NIAGARA FAN HEATERS AND HIGH PRESSURE STEAM FAN HEATERS For heating and ventilating large areas. Units of the highest quality in engineering, material and workmanship. Ask for Bulletins 78 and 109. NIAGARA MOTOR BLOWERS One, two and three-fan units. High and low static pressure models. Ask for Bulletin 89. 1186 tagara ATt8 \nd*n*cr unlk *0* and Balanced- .. _ ... . Central Systems Air Conatitontno Dehumidification y Units Pittsburgh Lectrodryer Corporation Foot of 32nd Street Pittsburgh, 30, Pa. FOR INDEPENDENT CONTROL OF DEHUMIDIFICATION IN COM FORT AND INDUSTRIAL AIR CONDITIONING The results of years of experience in the independent control of industrial dehumidification are now available for comfort air conditioning in the form of sturdy, dependable, thoroughly tested machines for controlled adsorption de humidification. LECTRODRYER equipment using Ac tivated Alumina, a solid adsorbent, is widely used in maintaining lower than normal.relative humidities in the chem ical, pharmaceutical and other indus tries. In comfort air conditioning these ma chines handle the latent heat load with only the sensible heat load left for refrig eration or water cooling. With this type system, only the air needed for the sensi ble heat load is cooled and no reheat is required. Machines are available for steam, gas or electric operation, whichever the pur chaser specifies. Standard machines aie available in several sizes ranging from 350 cfm upward. LECTRODRYERS are shipped com plete as self-contained automatic units in that they require no regular manual attention except for starting. They are built for continuous operation with reac tivation being carried on simultaneously with the drying operation. Write for full details. Air Conditioning Parks-Cramer Company Fitchburg, Mass. Charlotte, N. C. CERTIFIED CLIMATE Complete Air Conditioning Systems including Hu midifying or Dehumidifying, Cooling by Evaporation or Refrigeration, Ventilating, Filtering, Air Washing; with Automatic Control of Humidity, Temperature and Air Change. Air Conditioning <> Parks-Cramer Company Fitchburg, Mass. Charlotte, N. C. Automatic Airchanger An improved system of forced air change and distribution used with direct humid ification. Insures fixed uniform humidity and maximum evaporative cooling. Amount of air change and operation of humidifiers controlled by humidity and temperature Psychrost&t. Designed for either complete new installations or for supplementing existing direct humidify ing equipment. Especially beneficial with Gradumatics. Gradumatic Humidifying System New and vastly improved type of direct humidifying system for use alone, with Airchangers, or as booster for Central Station system. Air and water under pressure, water pressure always less than air. Safe. Economical. Humidifier is self-cleaning. Central Station Air Conditioning A complete system for conditioning air, with positive circu lation and controlled ventilation. One or more air washer and fan units. High humidifying and evaporative cooling capacity. Heating, filtering, and refrigerated cooling optional. Ducts with adjustable outlets distribute conditioned air uniformly. Slight air pressure also improves uniformity. Centralized maintenance. Used with or without booster humidification. Under complete automatic control. Exclusive multi-speed fan motor control available. Central Station Air Washer Units. Nozzles and Self-Cleaning Tank Screens tor Central Station Air Washers. Laboratory Air Conditioning An essential of a good testing laboratory is adequate and de pendable air conditioning. Accuracy in testing is maintained only when samples and testing equipment are free from fluctu ations in both temperature and humidity. A vertical or hori zontal unit is located within or adjacent to the laboratory. Includes equipment for heating, humidifying, dehumidifying, refrigeration, circulation, and adjustable recorder-controller. Heat by steam or electricity. 1188 Has few component parts, easy to take apart and reassemble. Proper operation as- sored without testing. No adjustment required. When humidification is needed, heads operate continuously, evaporative output being varied gradually and auto matically by Certified Climate Psychrosfcat to suit requirements for constant humid ity at all times. Certified Climate Psychrostat Improved model more sensitive than ever before. Rugged and Pliable. Use of the wet and dry bulb principle permits Psy chrostat to perform the many and varied tasks in the field f humidity and temperature control which contribute to the success of Certified Climate systems. * The Pettifogger (not illustrated) A compact centrifugal humidifier, with fan, for offices, storerooms, experimental rooms, hospitals, or other isolated departments. Self-contained in lacquered copper casing. Easily connected to water and electrical supplies. Automatic control. Adjust able capacity. Neutralizes drying effect of heating. 1189 Air Conditioning s,"ems United States Air Conditioning Corporation Engineers and Manufacturers of Air Conditioning, Refrigeration, Units Heaters, Coils and Ventilating Equipment 3321 Como Ave., S.E. usAIRta 30 YEARS OF AIR CONDITIONING For Industrial. Commercial and Residential Applications Minneapolis 14, Minn. Refrigerated Kooler-aire--Central Sta tion Air Conditioning plant (single or dual refrigeration circuit) with built-in evaporative condenser or water con denser. 3 to 50 hp sizes. Other models available for water chilling with either evaporative condenser or water condenser. Evaporative Condensers--A cooling unit that condenses refrigerants, available capacities from 3 through 100 tons. Permits water savings of 95 per cent. Upright Store Conditioners--A com pletely packaged room air conditioner built in: 2,3,5,7H and 10 ton capacities. Home Air Conditioner--Compressor type uses existing ductwork of warm air furnace. Available in 2 to 5 hp models. Motor compressor has 5 year warranty. Modu-aire--Individual room controlled coil and blower units which provide year around air conditioning without ductwork for multiroom buildings. Re cessed, free standing and horizontal models built in capacities from 300 cfm up. Unit Heaters--Suspension type heaters operating on steam, hot water or gas . . . built in a complete range of sizes. Blower Type Unit Heater--Floor, ceiling inverted or wall mounted models from 1000 to 33,000 cfm for industrial heating. Blowers--Backwardly or forwardly in clined blade blowers. Sizes and ca pacities for all cooling, heating, ventilat ing and air conditioning requirements. Unit Air Conditioners--Coil-blower units for year around air conditioning. Made in ceiling and floor models, from 1000 cfm to 12,000 cfm. Coils--Coils for every air conditioning requirement, including standard and steam distributing tube type steam coils, water coils for heating or cooling and direct expansion coils. 1190 ._ ... Central Systems. Air Conditioning Refrigeration and umt Heaters Westinghouse Electric Corporation Air Conditioning Division Hyde Park Self-contained Air Conditioners--2 to 25 tons; Heat Pumps; Field-assembled Air Conditioning Equipment Offices in all principal cities BOStOU 36, MftSS* AIR CONDITIONING UNITS Type HP Heat Pumps are flameless, water-less all-electric units which will heat the home in the winter and cool it in the summer--automatically. Recom mended for areas where extremes of tem perature are not of long duration. Avail able in 3 and 5 hp capacities. Type RU Unitaire conditioners are for residential application--occupy a mini mum of floor space. They come with or without a fan unit--are available with single or 3 phase electrical characteristics in 2,3, ana 5 ton capacitiesi Like all Unitaire conditioners they are easily installed--require only simple, water, drain and electrical connections. Where required they can be used in con junction with a duct distribution system. Type SU Unitaire Conditioners are pro vided with an attractively designed finished cabinet and are suitable for installation within the space to be con ditioned. They are widely used in stores, restaurants, office suites and similar establishments. Available in capacities of 2, 3, 5, 8, 10 and 15 tons. Type LU Central Plant Unitaire Con ditioners are designed for installation with supply and return air ducts and are available in capacities of 20 and 25. tons. Air-to-air Heat Pump REFRIGERATION compressors Type CLS Freon-12 Refrigeration Com pressors are hermetically sealed, direct, connected units with refrigerant cooled motors made in 12 sizes from 2 to 100 hp. WATER COOLED CONDENSERS Available in 14 sizes within the 2 to 100 ton range. Constructed with integrally nnned copper tubing and steel shells and tube sheets in accordance with the recommendations of Paragraph U-69 of 1 e ASME Unfired Pressure Vessel Code. DNIT heaters estmghouse horizontal Speedheaters-- mblS capacities of 25,800 to 300, jjjujltu/hr for steam, hot water, and gasured applications. o^ nblast Speedheaters project heated r downward to working level. Availao e in capacities of 40,000 to 400,000 plication s*'eam anc* hot water ap- Downtiast Speeiheater 1191 Horizontal Speedkeater Air Conditioning central Sjmems Albant Atlanta Baltimore Bibmingham Boston Buffalo Charlotte Worthington Corporation Air Conditioning and Refrigeration Division General Offices: HARRISON, NSW JERSEY Chicago Cincinnati Cleveland Dallas Denver Detroit El Paso Fort Worth Louisville Galveston Milwaukee Greenville, S.C. New Haven Houston New Orleans Kansas Crrr Knoxville New York Omaha Los Angeles Philadelphia Phoenix Pittsburgh Portland, Ore. Providence St. Louis St. Paul Salt Lake Citt Representatives in all Principal Cities San Francisco Seattle Springfield, Mass. Syracuse Tulsa Washington, D. C. Wilmington, Del. A.O.25 Packaged Air Conditioners Centrifugal Refrigeration Water Cooling Systems Provide cooling (and heating, if desired), dehumidification, ventilation, and air cleaning for commercial and industrial applications. 3, 5, 7), 10, 15, 20, and 25 ton capacities.. 150 to 1,200 tons, 56 unit sizes. Freon centrifugal compressor, water cooler and water-cooled condenser in compact unit assembly. Electric motor or steam turbine drive. ' Reciprocating Compressors Freon Air Conditioning 'Units V.and W type, to 150 tons with Freon-12 and to 170 tons with Freon-22. Full force feed lubrication above 10 hp. Ca pacity reduction and unloaded starting by magnetic' unloaders. Mounted on steel base, with water cooled condenser or for use with separate evaporative condenser. Evaporative Condensers Series AHY and AVY Central Station Air Conditioners for year-round air con ditioning. AHY units for horizontal air flow, ceiling mounting; AVY units ver tical, for floor mounting. 6 sizes, 2,000 to 17,500 cfm, 4 to 62 tons. With or without internal face and bypass dampcrs. Series ECZ, 10 to 150 tons. Section- alized construction, all parts easily ac' cessible. Galvanized steel coils for am monia, bare copper coils for Freon-12- 1192 Air Conditioning Central Systems York Corporation York, Pennsylvania Factory Branches and Distributer Engineering and Sales Offices throughout the World. Air Conditioning and Refrigeration for maintaining proper atmospheric conditions for industrial processes or comfort requirements. Installations of unit and central systems in a complete range of capacities and types for every design re quirement. Condensing and Water Cooling Systems--Turbo (centrifugal) . brine and water cooling systems (1) available over wide range of capacities^-up to 2500 tons refrigeration for Freon water cooling duty--suitable for steam turbine or motor drive. Selfcontained dynamically balanced, non-vibrating V/W type reciprocating compressors (2) available in capacities up to 350 tons refrigeration in a single unit, with water cooled or econo mizer type condensers. Efficient automatic capacity, reduc tion available for economical operation at reduced load. The York Economizer (3)--A combined force-draft cooling tower and refrigerant condenser, is available for installations where prohibitive water costs or inadequate drainage facilities preclude the use of a water cooled condenser. Standard factory constructed and built-up units may be used singly or in multiple for applications of any specified capacity. Econo mizers for use with Freon as the refrigerant are furnished, as standard, with a liquid sub-cooling coil. Economizers also designed for cooling of quench oil and other liquid coolants. Air Conditioning Units. A complete line of finned coil, dry coil, wetted surface and spray type sectional air conditioners for horizontal or vertical applications, designed to facilitate installation and the distribution of air. Standard units can be equipped with by-pass feature and arranged for cooling and dehumidifying, heating and humidifying. Yorkaire Unit Air Conditioner (4)--A compact, self-contained model occupying but 21 x 42 inches of floor space and requiring only water, drain and electrical connections to operate. Spec ial features provide utmost flexibility to meet varying condi tions. Finger-tip dial control provides automatic and manual temperature and humidity control. Air volume and motion may also be adjusted by a special control and the directional grille provides directed air flow--up, down or from side to side. May be used with ducts if desired. Yorkaire Conditioners are ruggedly built, quiet in operation, equipped with standard fan and compressor motors for AC or DC. Dehumidifiers--For central station systems where a. large volume of air is to be handled and where control of humidity is an essential requirement, the York dehumidifier is especially applicable. Construction features insure a minimum space demand and maximum performance conditions. Standard washers are available in a full range of capacities for industrial installation. 1193 .. Winter and / - Air Conditioning Summer Air Conditioners AiWERlCAN-c^taifdawI SUNBEAM AIR CONDITIONER DIVISION - - Elyria, Ohio Executive Offices: Bessemer Building, Pittsburgh 22, Pa. a division of American Radiator <& Standard Sanitary Corporation District offices in principal cities are listed tinder "Furnaces" or "Air Conditioning Equipment & Supplies" in the yellow pages of your telephone directory. RESIDENTIAL SUMMER AIR CONDITIONERS hSO| EBpllpB|! The MAYFAIR Summer Air Condi tioners are self-contained units with hermetically-sealed refrigerant circuits. Available in 2, 3 and 5 ton capacities with or without blower sections, units are idea! for combining with winter air conditioners to provide year 'round air conditioning. In modernization, summer cooling can be added to existing forced air furnace . . . uses the same ductwork. For basement or utility room installation. Listed by Underwriters Laboratories. COMMERCIAL SUMMER AIR CONDITIONERS The commercial MAYFAIR models-- 2, 3 and 5 ton capacities--are similar to the residential units, offering the same hermetically-sealed refrigerant circuits. Can be used singly or in multi ples. Ideal for shops, restaurants, offices and similar spaces. Listed by Under writers Laboratories. WINTER AIR CONDITIONERS (Gas Fired) The MOHAWK--a unit with cast iron leat exchanger and sturdy steel jacket or large or small homes. Preheated air iffers fuel economy, extra efficiency. Burners with removable ribbons for any ,ype of gas. In eight sizes with A.G.A. nput ratings of 80,000 to 300,000 Btu. The SENECA--an economy basement ,ype unit with copper bearing steel heat exchanger for' small and medium size lomes. Four sizes with A.G.A. input `atings of 85,000 to 150,000 Btu. The WYANDOTTE--a utility type jnit with steel heat exchanger for small lomes with or without basements. Factory,assembled and pre-wired. Five 3izes with A.G.A. input ratings of 55,000 ~ t.. r.:j_ __ + rot.lim air inlet. The WINTERLINE--a couhterflow unit for utility room installation iu basementless homes. In three sizes-- 76,000, 90,000 and 100,000 Btu output at bonnet. Approved for zero clearance. 1194 American-Standard Sunbeam Air Conditioner Div. Warm Air Furnaces NEW ELECTROSTATIC AIR CLEANER The MAGNE-FILTER--designed for easy installation in the return duct of any winter or summer air conditioner, this dry type electronic air filter traps even the smallest dirt par ticles, removes pollen, air-borne bacteria, dust and smoke from the air. Has perfected selenium type power pack. Made in seven sizes to meet all residential requirements. No water connection required. WINTER AIR CONDITIONERS (Oil Fired) The WINTERWAY is a basement type unit. Underwriters' listed with flange mounted Arcoflame burner. Stainless steel combustion chamber. Converts to gas. Heavy steel heating element. Five sizes--76,500; 90,000; 100,000; 120,000 and 150,000 Btu at register. Two smaller sizes factory assembled. The WINTERLINE--a counterflow unit for utility room installation in basementless homes. In three sizes--76,000, 90.000 and 100,000 Btu output at bonnet. Approved for zero clearance and converts to gas. Listed by Underwriters. The WINTERGLO--a utility type unit for small homes and individual apartments. In three sizes--76,000, 90,000 and 100.000 Btu output at bonnet. Underwriters' listed with Arco flame burner. Approved for zero clearance and converts to gas. Gas) . __________ ___________ _____ -- -- -- U1XU . The OLANDO--for oil--is available in 80,000, 100,000 and 112.000 Btu per hour at bonnet. Has heavy steel heating ele ment fired oy Arcoflame burner. Factory assembled and shipped with wiring harness for quick, easy installation. Listed by Underwriters. The PAWNEE--for gas--is A.G.A. approved for 60,000, 80.000 and 100,000 Btu input per hour. Burns all types of gas. Has heavy steel heating element and efficient slotted type cast iron burner. Factory assembled and pre-wired. WINTER AIR CONDITIONER FOR ALL FUELS The ARLINGTON--a moderately priced universal unit for all fuels. Has heavy steel heating element. In four sizes, rang ing from 67,800 to 134,000 Btu capacity at register. Also avail able as square or round jacketed gravity furnace, and pipeless furnace. FLOOR & GRAVITY FURNACES The NAVAHO--a gas fired shallow steel floor unit for homes with or without basements. Factory assembled. Available with floor grills or dual wall register. Manual or Automatic Controls. Three sizes, with A .G.A. inputs of 25,000,35,000 and 50,000 Btu. The SHAWNEE--a gas fired, compact steel furnace. Avail able in two factory assembled sizes, with A.G.A. inputs of 65,000 and 80,000 Btu. Other sizes available--105,000, 125,000 and 140,000 Btu inputs. 1195 ( ' Air Conditioning Air Conditioning Heating AIRTEMP DIVISION OF CHRYSLER CORPORATION. DAYTON I. OHIO "PACKAGED" AIR CONDITIONERS 2-, 3-, 6-, 8-, U- and 15-ton capacities. COMPLETE--Assembled and tested at the factory. Cools, dehumidifies, filters and circulates air. Free air discharge or duct distribution. Heating coil for yeqr-'round service optional. COMPACT--Entire unit is enclosed in "Bonderized" steel cabinet of modem design. Occupies very little floor space. EASILY INSTALLED--Needs only electric, water and drain connections. FLEXIBLE--Can be installed singly or in multiple to meet virtually every requirement. SEALED RADIAL. COMPRESSOR--Quiet with all moving parts balanced and bathed in oil for long life, flexibly mounted to reduce vibration. Optional 5-year warranty. , ROOM AIR CONDITIONERS and 1-hp Capacities. Ideal for home or office use. Fits in window. Cools, ventilates, filters and circulates. The % hp units operate with standard 115-volt current. The 1-hp unit requires 230 volts. Adjustable grilles provide controlled air circulation. Adjustable outside air in take. Cooling mechanism can be turned off for mild weather air circulation. PACKAGED LIQUID COOLERS. For use with Freon 12, sizes 3 to 75 hp. For use with Freon 22, sizes 25 to 250 hp. A com pletely assembled unit that is piped, pressure tested, dehy drated and with a refrigerant holding charge. RADIAL COMPRESSOR UNITS 10 to 125-hp Capacities. These heavy-duty units, for use with Freon, are especially designed for refrigeration and air conditioning. Radial com pressors are direct connected and have force-feed lubrication. Automatic capacity-reduction device. Light weight, econom ical to operate. INDIVIDUAL ROOM AIR CONDITIONING UNITS. Used for year-'round cooling and heating by connecting with central cold and hot water systems. Three types--floor, wall and ceiling--are available. Built-in controls make each unit independently operated. Two centrifugal fans provide cir culation. AIR-COOLED RESIDENTIAL AIR CONDITIONERS. Use no water, need no plumbing--all-electric operation. "Pack aged" model shown is complete with condenser and coil"Custom" unit, containing condenser, is primarily for outdoor installation, but under certain conditions may be used indoorsCooling coil in duct work completes system. 1196 AIRTEMP DIVISION OF CHRYSLER CORPORATION. DAYTON I, OHIO CENTRAL DUCT "PACKAGED" AIR CONDITIONERS . . . Self-Contained Central Type "Packaged;' Air Conditioners of 25,40,60 and 100 ton capacities. Utilize the Airtemp Radial Compressor with its exclusive features. Units available with evaporative condenser or for use with cooling tower. HORIZONTAL GAS FURNACE . . . Btu output from 48,000 to 80,000. May be installed in attic, under floor, or hung from ceiling. Dual flue outlets. Draft diverter mounts on either side. Automatic gas valve suitable for use with all types of gas.. Burner ignites instantaneously--single screw adjustment prevents clogging. Heat exchanger of efficient up-draft design with built-in baffles. Completely automatic controls fully enclosed- Steel cabinet "Bonderized" to resist rust. CONVERSION GAS BURNERS ... For quick, easy installa tion in existing furnaces. Combustion principle provides higher efficiency . . . minimum fuel consumption. Available in two models, capacities from 75,000 to 225,000. Btu. GAS- and OIL-FIRED AUTOMATIC FURNACES . . . HiBoy and Lo-Boy models heat, humidify, filter and circulate the air. 67,000 to 210,000 Btu output. "Bonderized" and insu lated cabinets. Burners start, stop and operate quietly, have many features for high-efficiency heating. Gas models ap proved by .4 O.A. Laboratories; oil models approved by tJnderwriiers Laboratories. OIL-FIRED BOILERS STEEL OR CAST IRON. . . .models from 77,000 to 264,000 Btu--for steam and hot water heating in every size and type of home. Complete with Airtemp burner and all controls. COMBINATION HEATING AND COOLING FOR THE HOME___ Combination of a Chrysler Airtemp 2-bp, 3-hp, 5-hp or 8-hp; "Packaged" Air Conditioner and any of the larger Chrysler Airtemp automatic furnaces. The same blower, filters and ducts oi the automatic heating system are employed for cooling in the summer. 1197 Air Conditioning uS""' Hayes Furnace Mfg. & Supply Co. . 2929 South Fairfax Ave., Los Angeles 16, Calif. (Telephone^Texas 0-3734) STAINLESS STEEL GAS HEATING EQUIPMENT DUCT FURNACES Constructed of Type 321 Stabilized Stainless Steel. Non-corrosive property of heat exchanger permits installation downstream of cooling coils 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, factories. Air throughput in Either direction. Draft Hood and Vent Manifold revers ible, adjustable for both horizontal and vertical connection. 14 sizes, 80,000 to 600,000 Btu per hr input in 40,000 Btu increments. A.G.A. certified for all gases. DUCT FURNACE MODEL SED-VF (Left). Tested and approved as a duct fur nace--Constructed of type 321 stabilized stainless steel. Re-circulated or fresh air is introduced through bottom, sides or back of furnace. Equipped with air by pass. Handles large cfm per Btu input. Vent in front of furnace. Made in 6 sizes from 70,000 to 245,000 Btu per hr input in increments of 35,000 Btu. For natural, manufactured and L.P. gases. FORCED AIR SUSPENDED FURNACE, MODEL SES (Right) Equipped to install in a sus pended duct system. Inlet and outlet designed for sheet metal duct connection. UNIT HEATER MODEL SEU (Left, Below). Used where room air is to be recircu lated. Diffuser outlet with adjustable vertical and horizontal vanes. Both types of Suspended units are de signed for factories, commercial and other large Btu requirements--equipped with brackets for suspension, save floor space. Double inlet forward curve blower. Continuous duty variable pitch drives; cast iron, raised port, precision machined burners. Made in sizes 80,000 to 480,000 Btu per hr input in 40,000 Btu increments. For natural, manufactured Suspended and L.P. Gas. FORCED AIR FURNACE MODEL SEC. Heat exchanger constructed of identical die formed sections of type 321 stabil ized 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. Finished in baked silver grey. 6 sizes 70,000 to 245,000 Btu per hr input in 35,000 Btu increments. For natural, manu factured and L.P. gases. ALL HAYES FURNACES ARE A.GM APPROVED 1198 Air Conditioning Automatic Equipment Gas and Oil Pennsylvania Furnace & Iron Company 316 North Pine St., Warren, Pennsylvania Representatives are in principal gas using centers. Pennsylvania Gas Furnaces, Floor Furnaces, Conversion Burners, Pennco Gas Fired Boilers for steam, vapor and water, for residences, schools, hospitals, hotels, stores, and any other type of build ing that requires a heating plant. A full and complete line of sizes. SERIES 6 PENNCO BOILER The Series 6 Pennco boiler is a large capacity type boiler. It is a cast iron sectional type with all sections having hollow pro jections which add to the heating surface. The sections are assembled on a specially designed steel base. The design of this base greatly reduces assembling time and reduces installa tion costs. . ' The Series 6 boiler sections are hydro-statically tested to 150 psi. All boilers are constructed in accordance with the ASME code. They are also approved by the A.G.A. Testing Labora tory. Twenty-six different sizes are available from 400,000 Btu per hr input to 4,000,000 Btu per hr input. All Series 6 Pennco boilers are furnished with completely automatic controls. SERIES 2 & 3 PENNCO BOILERS Series 2 & 3 Pennco boilers are the cast iron sectional type with all sections hav ing hollow projections to add to the heat ing surface and efficiency. Both the Se ries 2 & 3 are made in either Standard or Deluxe type. The Series 2 is made for water only in four sizes from 175 sq ft EDR to 350 sq ft EDR. The Series 3 is made for steam, vapor or water and is made in eight sizes from 96,000 Btu per hr input to 400,000 Btu per hr input. SERIES 10 PENNSYLVANIA FURNACES The Series 10 Pennsylvania Forced Air Furnace is constructed with an all steel combustion chamber and corrugated steel radiator. All joints and seams are continuous welded assuring gas tightness. A two-tone blue baked enamel casing contrib utes to the beauty of the Series 10 Pennsylvania furnace. This Series furnace is made in seven sizes ranging from 72,000 Btu per hr input to 265,000 Btu per hr input. SERIES 10-V VERTICAL TYPE PENNSYLVANIA FURNACE _ The Series 10-V vertical type furnace is constructed with the same type combustion chamber and radiator as the Series 10 horizontal. This unit is compact and made in three sizes; 60,000, 90,000 and 120,000 Btu per hr input. SERIES H AND SERIES 11 ULTRA The Series 11 and Series 11 Ultra are newly designed forced air furnaces. The Series 11 Ultra is constructed of 12 gauge steel to comply with SUR and for burn ing fuel oil and gas. Both series are available in three sizes--75,000, 100,000 and 125,000 Btu per hr input. This n IEr 55 PENNSYLVANIA GRAVITY FURNACES throo lne Pennsylvania Gravity Furnaces is made in towwwfhhot.iihcc-lt.hhio-s-n-f`ueozcnn.bsnitrls.ue'a0e>d0neaa0nd.u`1al 0fiir0n,s0isp0ha0cceaancsdoinn1gt2ra5ibn,0ud0t0espBteotcutihalepdeherisghighrneeinfdfpicluiinetn.incAgy The p , PENNSYLVANIA CONVERSION GAS BURNERS diarnot011 rvan*a Conversion Gas Burner is made in three sizes, 8 in., 10 in., and 12 in. Btu per^r ^rnet ^ea^s' an(l ranges in size from 80,000 Btu per hr input to 300,000 Air Conditioning L. J. Mueller Furnace Co. - Milwaukee 15, wis. Mueller ClimofrolHEATING AIK CONDITIONING Tvoe 101 (Gas) 201 (Oil) GaB-fired, steel, gravity furnace (convertible to, or avail able as oil-fired, Type 201). Available in four sizes with A.G.A. input ratings of 90-, 135-, 160- and 180,000 Btu. .. Type 105 (Gas) 202 (Oil) Gas-fired, steel, winter air-conditioner (convertible to, or available as oil-fired, Type 202). Available in nine sizes with A.G.A. input ratings of 100,000 to 675,000 Btu per hour116-216 Oil or gas-fired winter air conditioners. Small, compact, shipped assem bled and pre-wired. 90,000 to 150,000 Btu input. Convertible to oil or gas. L. J. Mueller Furnace Co. Air Conditioning HeS-cST"'1 Type ISO Type W . Type 111-tlt Type 160 Gas, direct-fired, steel, suspended unit heater. Horizontal tubular design. Propeller-type fan. Available in 7 sizes with A.G.A. input ratings of 50,000 to 225,000 Btu per hour. Type 151 Blower Unit Heater is available with A.G.A. input ratings of 60,000,90,000, 120,000, 150,000 Btu. Has similar construction to Type 155 horizontal winter air conditioner. Type 111 (Gas) and 211 (Oil) Gas-fired gravity furnace (convertible to, or available as oil-fired Type 211). 90,000 Btu input. Trim, compact, only in. wide. Shipped assembled. Type 110 Type 111 (One) and 111 (OH) Type 114 tGae) and 114 (Oil) Tvoe 110 Gas-fired, steel, winter air-conditioner for basements, closets or utility rooms. Available with A.G.A. input ratings of 60,000,80,000 and 100,000 Btu per hou . Type 112 (Gas) and 212 (Oil) Gas-fired, steel, winter air-conditioner (convertiDie to or available as oil-fired, Type 212). Two sizes: 90- and 110,000 Btu input Type 114 (Gas) and 214 (Oil) Gas-fired, steel, winter air-coI'ditin,er ^vertib^ oravailable as oil-fired, Type 214). A.G.A. input rating of 90,000,110,000 and 150,000 Btu. Type 10 Gas-fired, cast-iron boiler for residential heating, and hot-water supply. Controls enclosed. (Also with controls exposed, Type 11.) Approved for all types of gas. A.G.A. ratings of 290 to 2015 sq ft for water, and 180 to 1260 sq ft for steam. Type 21 Gas-fired, cast-iron boiler for larger installations. Sectional construction mcrease in increments of 70,000 Btu). A.G.A. approved. Ratings of 1870 to 22,400 sq ft for hot water, and 1,400 to 17,300 sq ft for steam. Type 35 Oil-fired, cast-iron sectional boiler for heating and hot water supply. Burner and controls enclosed. Convertible to gas. Available four to eight sections, with inputs from 240,000 to 560,000 Btu. Type 116 (Gae) and 115 (0.1) Type 155 Type 15S Type 115 (Gas) and 215 (Oil) Gis-fired steel, winter air-conditioner (eonvert>D to nr available as oil-fired Type 215). Counter flow design for perimeter heatinB. slVor crlwl-sp^e homes. A <?.A. rated at 80,000, 110,000 and 150,000 Btuinput. Type 155 Gas-Fired Horizontal Winter Air Conditioner Horizontal 1tubular h.^ exchanger May be suspended, or used for attic installations. Available A.G.A input ratings of 60,000 and 90,000 Btu per hour n,,drsft Type 253 oil-fired horizontal winter air conditioner or blower unit heater. UP w design, completely cleanable. All welded steel heat exchanger. Convertibl gas. Available in four sizes--110,000 to 250,000 Btu input. rvpe SOI Type SOS Type 804 niInfir :dr cn<iitioner available in 3-, 5- and 7-J^ ton sizes. Shown in- 180 000 and furnace *las A.G.A. inputs of 100,000, 150,000, col>ng.ul?it for home installation with any type warm air comple'te refrige t' *n ex'3^'n installations. Two, three, five ton sizes-- "Hh^raHia^6.^-contained cooling unit--for store, restaurants, duct systems in homes tons nt r rad'a*,or heat. Built-in blowers and filters. Two, three, five and 1201 Air Conditioning Rheem Manufacturing Company 570 Lexington Avenue, New York 22, N. Y. REGIONAL OFFICES ' Spabbows Point 19, Md. 4361 Fibestone Blvd., South Gate, Calif*. 7600 S. Kedzie Ave., Chicago 29, III. 800 Cheslby Ave., Richmond,--Callf. 1025 Lockwood Drive, Houston 20, Tex. 3693 E. Marginal Wat, Seattle, Wash. Every Rheem Furnace is "Fire-Tested" with pilot and burners ignited. Automatic controls, safety checks, operational and construction details must pass rigid tests. WARM-AIR HEATING EQUIPMENT . RHEEM GAS-FIRED WINTER AIR CONDITIONERS--Fully automatic, factoryassembled, forced-air furnaces of all-steel electrically welded construction. "Flame shaped" combustion chamber and multi-section heat exchanger specially designed to prevent expansion-contraction noise, provide high heat transfer in limited space. Features built-in draft diverter, enclosed controls; dynamically balanced, large capacity blower-motor assembly; gray, baked-enamel finish. Approved by A.G.A. for natural, mixed, manufactured, and LP gases. Units of Series 3202, 3203, and 3402 available for LP-Air and Dual Gas operation. Series 3202 and 3402 units also available with heat exchangers of 12 and 14 gage. Modd seat Model S!OS Moid SiOt Moid StOl Modd MB& Model 3202 Hi-boy--for first floor utility room or basement installations. Top rear flue outlet. Side or bottom filter frames. Casing sides equipped with knockout plates for optional side cold air return. Five sizes from 66,000 through 150,000 Btu input. Model 3203 Hi-boy--same as Model 3202 but with top front flue outlet. Six sizes from 60,000 through 150,000 Btu input. Units in lower input range available for zero clearance closet installation. Model 3402 Lo-boy--for basement instal- > lations. Top rear flue outlet with built-in draft diverter. Four izes from 77,000 through 150,000 Btu. Model 3201--zero clearance for closet, alcove utility room, or basement instal lation. Available in a wide variety of sizes and rated capacities. Model 3205 Counterflow--for perimeter heating applications. Blower-filter as sembly mounted in top of unit. Ample space in bottom of unit for humidifier installation. Two sizes: 80,000 and 100,000 Btu input. FORCED-AIR GAS-FIRED FURNACE FOR LARGE BUILDINGS Model 3200 forced-air furnaces designed for large residences, small commercial buildings, churches and stores. Five sires from 168,000 through 350,000 Btu input. A.G.A. approved for natural, manufactured, mixed and LP gases. 1202 Rheem Manufacturing Co. Air Conditioning Heamgtic OIL-FIRED WINTER AIR CONDITIONERS Model 2438 Lo-boy and Model 2436 Hiboy--pressure atomizing oil-fired. Three sizes: 85,000, 100,000 and 120,000 Btu bonnet output. Enclosed burner and controls. Readily converted to gas-firing. Modd 438 RHEEM GAS GRAVITY FURNACES Model 3302 fully automatic, factory-assembled, gas-fired gravity furnaces designed for low cost installation and trouble- free operation. "Flame-shaped" combustion chamber and multi-section heat exchanger of all-steel, electrically welded construction. . Features include inner casing installation, enclosed controls, optional side gas connection, and rectangular-shaped casing finished in gray, baked enamel. A.G.A. approved for natural, manufactured, mixed and LP gases. Five sizes: from 77,000 through 187,000 Btu input. Model 3S0 RHEEM GAS-FIRED RECESSED WALL HEATERS Model 1801 compactly designed for small homes, "hard-to- heat " rooms, and small commercial applications. Easily in stalled between in.-studding. Neutral ivory casing only 60 in. high, 17 in. wide. Features built-in controls, porcelaneous heat exchanger, built-in draft diverter, front casing Fiberglas insulation. single wall unit A.G.A. rated at 28,000 Btu input; dual wall --50,000 Btu input. Available with thermostat or manual con trols for natural, manufactured, mixed and LP gases. RHEEM GAS-FIRED CONSOLE HEATERS Model 1703 attractively styled, easily installed with minimum space requirements. Ready access to burner and controls. eatures built-in draft diverter. Available with thermostat or manual controls. A.G.A. approved for natural, manufactured, mixed and LP gases. Three sizes: 25,000, 35,000 and 50,000 otu input. RHEEM GAS-FIRED FLOOR FURNACES d:rf compact, space-saving units in flat register and jj 3 types. Only 25j^ in. overall depth. "Pillow-type" exc anera designed for rapid, efficient heat recovery n expansion-contraction noise. A.G.A. approved for Ura ' manufactured, mixed, LP and LP-Air gases. . 1203 Modd 1703 Series 1603 B {fiat register) Series 1603 B 6dual wall) Air Conditioning gEfZS&S? REGIONAL OPRICES New York--Atlanta Chicago -- Dallas Loe Angeles Air Conditioning Division Evansville 20, Indiana Air Conditioning Equipment for residential, commercial, and industrial applications SERVEL ABSORPTION-TYPE units are hermetically sealed, and operate without moving parts. Water is the refrigerant, lithium bromide the absorbent, and steam the source of energy. The most economical steam source may be used to operate these units. They may be operated at partial capacity without use of complicated controls. They may be installed in compact groupings in any convenient builder location because the units are quiet and vibrationless. Servel Air Conditioning Division Air Conditioning tgSfSJlSSffi? SERVEL ALL-YEAR AIR CONDITIONER MODEL DE Delivers 5 tons of refrigeration with 96,000 or 144,000 Btu/hr of heating. Operated on existing steam source' or comes complete with gas or oil boiler and controls. SERVEL ALL-YEAR AIR CONDITIONER MODEL DC Provides 3.3 tons of refrigeration with 96,000 Btu/hr heat output. Operates on existing steam source or comes complete with gas- or oil-fired steam generator and controls. SERVEL 25-TON WATER CHILLER MODEL DDT. An economical source of chilled water for industrial processing and air conditioning for office build ings, hospitals, factories. 25-ton capac ity ASRE rating. SERVEL DIRECT EXPANSION UNIT 3- and 5-ton nominal capacities. May be used separately or in combination with other parts of SERVEL Air Condition ing equipment under "Incremental As sembly Plan." SERVEL "CORROSION - MASTER" WATER COOLERS for use with Servel units where city water is limited, too warm, or costs too much; or where a well is impractical, or drainage insufficient. MODEL TE-10--used with DC model Air Conditioner. MODEL TE-15--used with all DE models. 1204 SERVEL ALL-YEAR AIR CONDI TIONER MODEL EB-72-G Delivers 2 tons of refrigeration with '2,000 Btu/hr heating output. Gas burn ers supply the energy for absorption rerigeration unit and also heat in winter. SERVEL ELECTRIC "PACKAGED" AIR CONDITIONERS MODELS 130E, 150E, 175E. These compact eleetricroperated units are designed for ease of installation; nominal refrigeration capacities of 36,000, Vod& 60,000, and 90,000 Btu/hr. Servel superI-50E matic compressors are semi-hermetically sealed and direct drive motor type. An optional accessory of hot water or steam coil is available to furnish winter heating when year-round service is desired. SERVEL 5-YEAR WARRANTY--ALL SERVEL absorption equipment carries a 5-year factory warranty. 1205 Air Conditioning . Surface Combustion Corporation Janitrol Executive Offices: 2375..Doit St., Toledo 1, Ohio * Winter and Summer Air Conditioners, Gravity Furnaces, Conversion Burners, Floor Furnaces, Domestic Hot Water and Steam Boilers. Gas or Oil Fired. Complete specifications and performance data are available upon request from the Engineers Service Bureau of Surface Combustion Corporation. WINTER AIR CONDITIONERS. . .Available in a complete range of sizes which may be used successfully with either radiant or convection systems. These condi tioners are suitable for use with small diameter duct systems and for perimeter heating. Construction features include choice of Dura-tube (for greater protection against rust and corrosion) or standard steel heat exchangers,-patented design ribbon burn ers, large capacity blowers and filters. A.G.A. approved for sea level and at high altitude operation; also approved for close clearance alcove and closet installations (subject to local building codes). For all gases including L-P. Model FEC-45 Conditioners (Dura-tube heat exchangers): ^e-Vrmanre Model No. FEC60-45 FEC76-45 FEC9045 FEC105-45 Ratings-- dtu per hr. A.G.A. Input ` A.G.a: Output At Bonnet 6U.00U 75,000 00,000 105,000 48,000 60,000 72,000 84,000 CFM Del. for F Temp. Rise 80 100* 525 418 655 525 790 630 920 733 Motor HP 115 60-1 No. M2 W2 H2 W2 Filters Site 16 X 20 X 2 16 X 20 X 2 20 X 20 X 2 20 X 20 X 2 FEC120-45 FECI50-45 FRCIW-Jfi Vodel No. FEC60-45 FEC75-45 FEC90-45 FEC105-45 120,000 150.000 isn non 96.000 120,000 144.000 1050 1310 1575 841 1053 1260 Dimensions--inches Cabinet M Width ac Height Q Outlet mi 26 G0M 18*4 26 60*4 22*4 26 60*4 25 26 60*4 8 X 15*4 8 X 15*4 8 X 19W 8 X 22X H 2 25 X 20 X 2 H 4 16 X 20 X 2 14 4 20 X 20 X 2 Return Air [nlet 9*4 X 16*4 9*4 X 16W 9*4 X SOW 9*4 X 22H Approx. Ship. Wt., Lbs. 312 325 356 380 FEC120-45 FEC150-45 FEC180-45 28 26 mi 34*4 26 60*4 42*4 26 60*4 8 X 25*4 8 X 31*4 8 X 39*4 9*4 X 25*4 9*4 X 32*4 9*4 X 40*4 407 481 572 Model FES-45 Conditioners: The model FES-45 conditioners (with steel heat exchangers) are available in 7 sizes which are similar in dimensions and performance to the 7 sizes of the Model FEC-45 conditioners described above. Large Capacity Model FES Conditioners (steel heat exchangers): For use in more spacious homes, in public buildings and in commercial installations, the model FES-45 conditioner ^is available in the capacities described below. . performance Model No. FES210-45 FES240-45 FES300-45 FES360-45 Ratings--] Hu per hr. A.G~A. Input A.Q^A. Output at Bonnet 210,000 240,000 300,000 360.000 168.000 192,000 240,000 288,000 CFM Del. for F Temp. Rise 80 100" 1840 2100 2620 3150 1466 1682 2106 2520 Dimensions--inches Motors 230-60-1 No. H.P. 2 *4 2H 2 *4 2H No. 2 2 4 4 Modd No. FES210-45 FES240-45 FES300-45 FES360-45 Width 50*4 56*4 68*4 84*4 Cabinet Depth 26 26 26 26 Height 60*4 60*4 60*4 60*4 Warm Air Outlet 8 X 48 8 X 54 8 X 68*4 8 X 82*4 Return Air Inlet 9WX48H 9HX54H 9*4X66*4 9*4 X 82*4 1206 Filters Size 20 X 25 X 20 X 25 X 16 X 25 X 20 X 25 X Approx Ship Wt, Lb* 750 802 950 Air Conditioning AutomaticvEquipment Gas FiredjfU&its Surface Combustion Corporation Janitrol Executive Offices: 2375 Dorr St., Toledo 1, Ohio Unit Heaters, Heavy Duty Blower Type Heaters, Floor Type Unit Heaters, Duct Furnaces, Large Capacity Conversion Burners, Kathabar Humidity Control Systems for Comfort and Processing. Gas Fired; Complete specifications and performance data are available upon request from the Engineers Service Bureau of Surface Combustion Corporation. UNIT HEATER. . '.Janitrol suspended type unit heaters are self-contained heat ing plants circulating large volumes of heated air. The unit is suspended over head and utilizes a propeller type fan to direct warm air to the space where heat is most useful. The patented ribbon burners occupy a fixed position beneath the steel heat ex changer tubes which helps insure maxi mum equipment life, evenly distributed temperatures, and high operating effi ciency. This unique combination makes extra head room available underneath the unit because of its compact design. DuunnoiMl Drawing structed to provide quick, easy access to internal parts should servicing be re quired. Available for all gases including L-P. For high al titude operation consult a Janitrol representative, or write tc home office (address above). Performance Model No ~~ UBS50-94 UBS65-94 UBS85-94 . Ratings--Btu per hr. A.Q.A. . AO.A. Input 1 Output* 50.000 65.000 85.000 40.000 52.000 68.000 Sq ft Steam Rad Equiv. 167 217 283 Air Deliv., CFM 780 850 1235 Motor HP Ho Ho Ho Approx. Snip Wt, Lbs 133 152 191 UBSI00-94 UBS125-94 UBS165-94 100,000 125.000 165.000 80,000 100,000 132,000 333 1525 *4o 206 417 1825 *4o 244 550 1730 *4 298 UBS175-94 UBS200-94 UBS225-94 175.000 200.000 225,000 140.000 160.000 180.000 583 2180 *6 298 667 2225 *4 352 750 2860 *4. 352 product* nf "T excessive air changes sufficient to adequately dispose of tl assumed to beTO^8**00 anc^ ur"l " unventod, the available output can 1 Modd UBSSi Dimensions--inches Model' 1 _ NNoo." 1 A B C n E FGH UBS85-94 ! toff HfSlOO-94 30u UBS165-94 MU OBg&JJ JJg tBS22o-91 5*4 14*4 5*4 15*4 5*4 18*4 5*4 18*4 5*4 20*4 6*4 20*4 6H 20*4 6*4 20*4 6*4 20*4 6 13*4 6 16*4 7 19*4 7 22*4 7 25*4 8 21*4 8 21*4 8 25*4 8 25*4 12*4 15*4 18*4 17*4 20*4 23*4 21*4 24*4 20*4 20*4 24*4 24*4 26*4 29*4 25*4 ' 25*4 29*4 29*4 22 22 *4 24*4 24*4 24*4 33*4 33*4 34*4 34*4 1207 J 9*4 9*4 10*4 10 10 13*4 13*4 13*4 13*4 K 12*4 13*4 13*4 14*4 14*4 21*4 21*4 21*4 21*4 L MN 5 13*4 17 5 13*4 17 6 12*4 17 6 12*4 17 6 12*4 17 7 12*4 20 7 12*4 20 8 12*4 20 8 12*4 20 / Air Conditioning Automatic Heating, Evaporative Air Cooling and Blowers Utility Appliance Corporation 4851 South Alameda St., Los Angeles 58, Calif. Cable Address: utilifan, Los An*ei Forced Air Furnace Horizontal Forced Air Furnace Floor Furnaces--Flat and Dual Vented SO UF Unit Heater FORCED AIR FURNACES Compact design permits use in basement or closet. Approved for zero clearance. Dynamically-balanced blower. Fiber glass filters. Heavy gage steel. 70,000 to 200,000 Btu. COUNTERFLOW FURNACES Designed for perimeter and all low-duct installations. Oversize blower for more effective heat distribution. Compact to save space. Models: 70,000 and 105,000 Btu. HORIZONTAL FORCED AIR FURNACES Designed to save floor space. Made for easy installation in out of the way places--can be installed in attic, under ceiling or under floor. Models: 65,000 to 140,000 Btu. FLOOR FURNACES FLAT AND DUAL VENTED Quiet, trouble free service. Highest quality materials. Four basic models: 45,000 Btu and 60,000 Btu. Floor and Dual Register. Controls: (1) Manual, manual pilot: (2) Manual 100 per cent safety pilot; (3) Automatic, self-generat ing safety pilot. WALL HEATERS Fit standard 4 in. stud without furring. Adjustable for wall thickness from 4% in.-5J4 in. Single or dual. Optional Thermostat or 3-rate manual control. Vented. Models: 27,500 Btu to 50,000 Btu. 50 UF UNIT HEATER Especially designed for installations where high heat efficiency is required in an extremely compact, attractive unit. Adjustable grille. Summer switch pro vides air circulation for warm weather ventilation. 50,000 Btu. UNIT HEATERS Suspended type.. Complete unit, burner, heat exchanger, draft diverter, motor fan and all other parts housed steel cabinet; baked enamel finish. Ad justable grilles. Models: 65,000-90,000 150,000-225,000 Btu. A.G.A.'approved Write for complete information, catalogs and prices. 1208 Counterflow Furnace Wall Heater Unit Heater Air r'nnHifinninn ,, Automatic Heating, Evaporative AVT LsOTtUltlOTUng Air Cooling and Blowers Utility Appliance Corporation 4851 South Alameda St., Los Angeles 58, Calif. Cable Address: utilifan, Los Angeiea Manufacturers of Utility Air Coolers Model 1200-P and 1600-P Fan Cooler. Designed for either permanent or port able installation. Features built-in re circulating, belt-driven pump. Com plete with cord, plug, motor switch, water control valve, window filler panels. May be permanently connected to water line or hand-filled. Model ItOO-P and 1S00-P Fan Cooler Blower Models 4000BD-4500BD. Bot tom Discharge Model is designed to eliminate duct work in most installa tions. Also enhances roof installation with elimination of duct elbow. Blower Models 4000BD-1500BD Blower Models 2000-2500. Ideal for small apartments, trailers and large single room installations. Can be in stalled with duct or in window. Com plete with cord, switch and water valve. Model 1S00 Fan Cooler Model 1200 Fan Cooler. Designed for permanent installation in any standard double-hung window up to 36 in. wide. Equipped with cord, plug, motor switch and water control valve. Complete with window filler pads. Blower Models SOOO-S50O Blower Mode] 3000. For small homes and office buildings. Adaptable for duct or window installations. Model 1000-P Room Cooler Model 1000-P Room Cooler. Comes complete with built-in pump, cord, plug, motor switch, water control valve and window filler panels. Two-speed con trol. Trailer Model Cooler. Installs flush with roof of trailer. Bottom discharge fits standard trailer vent. Blower ModebSOOO Blower Models 5000, 5500, 6000 especially designed for large residences, multiple dwelling units or commercial installa tions. Trailer Model Cooler Models 6500, 7500, 8000 for large office spaces, factories, warehouses. Models 10,000-11,000 and 13,000 for all com mercial installations, factories, ware houses, theatres, churches, auditoriums. 1209 Blower Models 5000-5500 6000-6500-7500-8000 10000-11000-15000 Ib i IS !' < Air Conditioning Automatic Heating, Evaporative _ Air Cooling and Blowers Utility Fan Corporation A Division of Utility Appliance Corp. 911 East 59th Street, Los Angeles 1, Calif. Cable Address: Utilifan, Los Angeles Manufacturers of heavy and standard duty blowers for heating, air condition ing and ventilating installations. Pro ducers of blowers and blower parts for original equipment manufacturers. Built, tested and rated in accordance with . A.S.H.V.E. and NAFM codes. Sizes 6 inches to 60 inches. , * Write for catalog data. MEMBER OF THE NATIONAL ASSO CIATION OF FAN MANUFACTURERS Direct-Drive Blowers Air Conditioning Oil Gas Coal Furnaces Syncromatic Corporation Watertown, Wisconsin HEAVY DUTY STEEL FURNACES OIL -- GAS -- COAL 330,000 to 1,000,000 BTU Output MANUFACTURERS OF WARM AIR HEATING EQUIPMENT DISTRIBUTED THROUGH RECOGNIZED WARM AIR WHOLESALERS IN PRINCIPAL CITIES Series 11 O. B. A The Utility Fan Corp. manufactures a complete line of blowers designed and built to meet any application. Utility blowers are available in all drive and discharge arrangements. Rigid wheel construction permits heavy duty service. Utility blowers comply with the most rigid specifications, and are tested and rated in accordance with the Standard Test Code for Centrifugal and Axial Fans, adapted by The American Society of Heating and Ventilating Engineers. Following are standard features of all Utility blowers: DYNAMICALLY BALANCED BLOWER WHEELS--To eliminate vi bration, insure quiet operation, high efficiency of performance and long life, Utility blower wheels are dynamically bal anced TWO-PIECE SCROLL HOUSING--To facilitate handling, scroll housings on No. 5}4 blowers and larger are built to permit disassembly into two pieces. HOISTING HOLES--For easy lifting, hoisting holes are placed on the heavy angle iron frames to prevent damage to the blower. ; Blower 4-Way Discharge LOW OUTLET VELOCITY-QUIET OPERATION--Advanced design of Utility blower wheels gives optimum performance at each specified diameter, insures quiet operation and long life, and reduces power cost and bearing wear. WELDED JOINTS--For maximum strength, minimum vibration and the ultimate in quiet operation, all joints and seams are welded. HEAVY GAUGE, DURABLE PAINT FINISH--Heavy gauge steel, protected with a durable paint finish, insures long life of Utility blowers. ^ SELF-ALIGNING PILLOW BLOCK BEARINGS--Selected for large oil reservoir and extreme durability under severe heavy duty service. , On outside installations, enclosed drive unit protects motor, pulleys and be* from weather exposure. . Range of air flow: 200 to 175,000 ctm- Single and double widths and inlets. Utility blowers are available^ in twj and triple unit assemblies. Lses on > one shaft, one motor and one set drives. 1210 SYNCROMATIC HI-CAP furnaces for schools, churches, theatres, auditoriums, gymnasiums, stores, garages, factories, etc. are designed primarily for use with duct systems. Flexibility in design permits wide range of blower sizes with each size unit. Units can be furnished with internal Bi-Pass for air condition ing installations. These furnaces as indicated can be operated efficiently with oil, gas or stoker. Also available for hand-fired coal with ratings 75 per cent of stoker fired. MODEL NUMBER Y)FB 33 OFB 40 OFB 45 OFB 50 OFB 55 OFB 60 OFB 70 OFB 80 OFB 90 OFB 100 B.T.U. OUTPUT AP BONNET 330.000 400.000 450.000 500.000 550.000 600.000 700.000 800.000 900.000 l.ono.ooo CTM AT 2" ext. ST. PR. 4.000 4.850 5.800 5.800 6.800 7.500 8.500 10.000 11.500 13.500 a .ss *e2 s 1.0 1.0 1.5 1.5 2.0 2.0 2.0 3.0 3.0 3.0 DIMENSIONS L wH 53 102* 72" 53 102* 72" 53 102* 72" 67 110' 72" 67 110* 72" 67 no* 72" 81 118' .84" 8) 118' 84" 95 132' 84" 95 132* 84" s H >2 H 09 12" 12" 12" 14" 14" 14" 16" 16" 18" 18" FIRING RATES OIL G.P.H. .1030 B.T.U. GAS C.F.H. 8TOKEB lb/hb APPROX. SHIPPING WEIGHT 3.0 3.5 4.0 4.5 5.0 5.5 7.0 8.0 9.0 10.0 393 476 534 595 655 715 835 950 1075 1145 35 4180 9 40 41809 45 42309 50 4884 9 55 4934 60 4934 70 6357 80 6617 90 100 7307 7517 *50,000 Btu '`<M-Fir5.R!ES $0 to 146,100 Btu "500" Series OH or Gas H1-BOY, Counterfiow or LO-BO Y GFU Gas Fired HI-BOY 75 & 95,000 Btu GF Gas Fired LO-BOY "900" Series OH Fired 75 to 115,000 Btu 80 to 108,000 Btu mP ete line of warm-air furnaces for residential heating in Gas, Oil and Coal Complete .an US1/lg Patented Counter Flow heat exchanger principle ' of the above ratmgS fr?n? 60-000 to250,000 Btu output. Separate catalogs on all Erie write tn able on retluest- For complete information on Hi-Cap wr,te to. SYNCROMATIC CORPORATION, Watertown, Wisconsin. 1211 W idth Casing H eight Casing iis ii wm Air Conditioning Automatic Equipment Heating Systems The Waterman-Waterbury Co. Minneapolis 13, Minnesota Manufacturers of WATERBURY Coal, Oil and Gas ' Fired Furnaces and Air Conditioning Equipment WATERBURY COAL-FIRED AIR CONDITIONER Modern winter air conditioning, added to the dependable Waterbury coal-fired furnace. Has a gas-tight, welded steel furnace body, featuring a large combustion chamber and radiator with long fire travel to insure efficiency and economy. W idth ' Casing Length Casing H eight . Casing 1No. of 1 Filters Size Output BTU Per Hr Size Size Outlet Inlet Open Open ing ing A120B-10* AI22B-I0* A124B-12* A127B-15* A130-18* A133-22* A136-22* 95,400 105,800 118,200 153.000 205.000 250.000 300.000 38' 40 42 46 53 55 64 60* 62 64 74 93 99 108 52* 52 52 59 57H 67 67 * Also available as a Gravity Furnace. 28x34 28x36 34x38 34x42 49x49 51x51. 60x60 16x34 20x36 20x38 22x42 36x36 40x40 40x40 Size Each Filter Size Fuel Door Htg. Flue Surf. Pipe Sq Ft Dia. CFM Range 2 16x20 2 20x25 2 20x25 2 20x25 4 16x25 4 20x25 4 20x25 IWxUH UHxllH MlfxllJi 141&11K 14KH1H 35.7 39.6 44.3 57.4 76-0 94.0 112.0 8'' 600 to 1400 8 600 to 1400 9 1000 to 2400 9 1600 to 3200 9 2800 to 4800 10 4000 to 6500 10 4000 to 6500 WATERBURY GAS-FIRED AIR CONDITIONER Designed specifically for most efficient use of gas. Enclosed in the compact, baked enamel casing, it is completely auto matic, providing filtered, humidified forced air. Can also be furnished for liquefied petroleum gas. Size Input Rating BTU Output BTU Per Hr Per Hr 6412-7* 6413C-9*t 6415C-10*t 6418C-12*t 6O4T2^U0VC>--1150___ _ 60.000 90.000 120,000 150.000 I1Q8O5..U0U0U0 48.000 72.000 98.000 120,000 H14fl8..U00W0 * Also available as a Hi-Boy. 3 Size Outlet Open ing Size Inlet Open ing No. of Fil ters Size Each Filter >4 22* 42* 42' 18x18 18x12 1 16x25 28 59 50 24x24 24x16 20x25 28 62 55 24x24 24x19 2 16x25 34 71 55 30x30 22x30 2 20x25 v3w6 v6~5 --55 3--2x32 32x22 2 20x25 t Also available aa a Gravity Furnace. Size Flue Gas Pipe Connec. Dia. Re quired 5' 5 \6 u7 8i CFM Range Waterbury Gas Conversion Burner A real gas burner, the same as used in the Gas Furnace and Air Conditioner. Maximum i Maximum Number Maximum Cubic Feet of Cubic Feet of BTU Input Mired Gas [Manuf'd Gas G-200 200.000 250 1 360 1212 Air Conditioning The Waterman-Waterbury Co, Minneapolis 13 Minnesota WATERBURY SUSPENDED OIL-FIRED FURNACE Built for installation where more space is available at ceiling level than on the floor. All parts are accessible from the front for easy cleaning and servicing. W idth Casing H eight Casing Length Casing No. of F ilte re Size Input Rating Gal. CM Per Hr Output BTU Per Hr Size Outlet Open ing Size Inlet Open ing 313 D-10SU 315 D-12SU 3ISD-15SU 320 D-15SU .75 1.00 1.35 1.50 84,000 28* 28' 78* 24x24 24x24 112,000 28 28 88 .24x24 24x24 151,000 34 34 92 30x30 30x30 168,000 36 36 92 32x32 32x32 Size Each Filter Flue Smoke Pipe Diam. CFM Range 2 16x25 6' 2 16x25 7 1000 to 2400 2 20x25 7 2 20x25 8 1600 to 3200 WATERBURY OIL-FIRED AIR CONDITIONER 6300 SERIES Completely automatic oil heat, plus the equipment to provide forced, filtered, humidified air, all enclosed in one compact casing finished in baked enamel. 1 W idth : 1 Casing 1 Length I Casing 1 H eight 1 Casing No. of F ilte rs Size Input Rating Gal. Oh Per Hr Output BTU Per Hr Size Outlet Open ing Size Inlet Open ing 6313C-9* 6315C-10* 6318C-12* 6320C-15 .75 1.00 1.35 1.50 84,000 112,000 151,000 168,000 28' 59' 50' 28 62 55 34 71 ,55 36 60 55H 24x24 24x24 30x30 32x32 24x16 24x19 22x30 32x22 Also available aa a Hi-Boy and aa a Gravity Furnace. Size Each Filter ao 5 1 20x25 6* 2 16x25 7 82 20x25 7 2 20x25 WATERBURY OIL-FIRED AIR CONDITIONER B 300 SERIES Designed especially for large installations, the B 300 Oilred Air Conditioner has a unique furnace body. It features an extra large radiator with a baffle for unusually long fire ravel, thus assuring efficient use of the fuel. Adaptable to gas. Length Casing H e ig h t Casing 1N o. of F ilte rs Width Less Front Hood 44' 48 52 56 60 66 72* 88 92 100 108 114 Size Size Outlet Inlet Opening Opening 55* 40x40 55 44x44 62 48x48 62 52x52 70 56x56 70 62x62 24x28 36x36 36x36 40x40 44x44 44x44 2 4 4 4 4 4 Size Each Filter Flue Pipe Dia. CFM Range 20x25 16x25 16x25 20x25 20x25 20x25 8' 1600 to 3200 9 2800 to 4000 9 2800 to 4800 9 4000 to 6500 10 5000 to 8000 10 7000 to 10.000 ____________________ Air Conditioning ^t(gg^1Hea,hg American Foundry and Furnace Co. General Offices: Bloomington, Illinois, P. O. Box 904 Sales Offices --... Atlanta 6, Ga. Boynton Cole Boston, Mass. Foulds Associates Buffalo 2, N. Y. Arnold R. Kamman Co. Chicago, 111. D. P. Gladish Co. (Glenview) Cincinnati 2, O. Walter A. Juergens Cleveland 7, O. Am. Warming & Ventilating Co. Denver 2, Colo. Kent Engineering Co. Des Moines 9, Ia. C. H. McGuiness Co. Detroit, Mich. H. J. Clemens . Elmira, N. Y. Am. Warming & Ventilating Co. . Gband Rapids 2, Bennett Heating Equipment Mich. * Co. Indianapolis 18, Ind. Elliott-Williams Co. Kansas City 11, M o. ' John H. Kitchen & Co. Los Angeles 7, Harry F. Haldeman, Inc. Calif. Milwaukee 2, Wis. Nashville, Tenn. New Orleans 15, Am. Foundry A Co. Cooper A Winters R. K. Rothrock Furnace ' La. New York 68, N. Y. Oakland 12, Calif. Philadelphia 2, Pa. Richmond 25, Va. Rochester 7, N. Y. Seattle 9, Wash. St. Louis 17, Mo. Salt Lake City 1, Utah San Antonio 6, Tex. Syracuse, N. Y. Toledo 4, O. Toronto 5, Canada West Lafayette, Ind. The Demuth Co. Aladdin Heating Corp. Am. Heating A Ventilating Co. < Richmond Air Equipment Co., Inc. Arnold R. Kamman Co. McPherson Furnace A Equip ment Co. M. F. Cariock Williams, Gritton A Wilde Langhammer-Rummel Co. F. W. Chadwick Co., Inc. Am. Wanning A Ventilating Co. Michael Stuart Co., Ltd. F. H. Speaker A Son, Inc. a?? 'S$ -5r JSi 8 - .ti 45 HEAVY DUTY FORCED WARM AIR HEATERS Heavy Cast Iron Construction--Inte grally Cast Fins. Shipped Knocked Down--Assemble In side Building. Tight Bolted Joints. Long Fire Travel--Ample Heating Sur face. .A" Design Relieves Internal Stresses When Expanding. Horizontal Flues With Access Doors Facilitate Cleaning. CENTRAL TYPE "June-Aire" conditioning for schools, public and commercial buildings. Heats and ventilates with same system. Out side air and recirculated air used in any desired proportion. Air' filters--Germ killing means. Atomist humidifier-- Humidistat control. Individual room temperature control with constant venti lation. Time clock program control of plant. Oil, Gas, Coal (hand or stoker fired) and convertible models. Capacity for buildings of any size. Warm floors (air tubes in slab) combined with window sill air supply, optional application method. Summer cooling by adding com pressor and coil. UNIT HEATER TYPE "Superfin" (Cast Iron*) and ``Dyne- Aire" (Stainless Steel) for factories, in dustrial buildings, warehouses, etc. Com plete heating plant in one package. Use for heating and ventilating or tempering outside air supply. Main blower, burner, and induced draft fan driven by separate motors. `Cast iron units with built-in refractories recommended for heavy oil- RESIDENTIAL UNITS: ``June-Aire' cast iron--oil and gas fired. Complete information available at near est sales office or factory. 1214 American Foundry and Furnace Co. Air Conditioning Automatic Heating Air Control AFFCO" VENTILATING SPECIALTIES "Affco" Specialties Comprise A Full Line Of Fresh Air Intakes, Outside Wall Ad justable Louvers, Dampers (Single and Multiple Blade--Parallel and Opposed Blade), Automatic Fire Dampers, Fan Outlet Louvers, Fan Pent Houses, Low Profile Roof Ventilators, Et Cetera. Used in Public, Commercial, Factory, and Industrial Buildings Including Power Plants. Inquiries Invited On Standard Or Special Con structions In Any Size, Any Metal, Any Quantity. S-454-F COMBINATION STORMPROOF LOUVER AND DAMPER Frame: 20 gage galvanized steel. Sta tionary Stormproof Louvers: 26 gage galvanized riveted to frame--apron ex tends over sill. Insect Screen: 16 mesh, rust-proofed, in removable "U" type frame, back of sta tionary louvers. . Louver Control Damper: 16 gage gal vanized steel multiple blades in 2 x x i galvanized steel channel frame. Manual or motor operation means available. Wall Thickness: 8 in. minimum. F-12 LOUVER DAMPER Frame: 2 x $ x f steel channel, 2 x l bar iron optional, heavier frames for large sizes. Blades: 16 gage steel. Bearings: Oilite, ball, or brass trunnions. Position Installed: Vertical or horizon tal. Maximum Blade Length: 48 in. Longer dampers are made in sections with all blades.arranged to operate in unison. Motor Mounting Brackets: Internal or external--at extra charge. Motors and Connecting Linkage: By others, or from us at extra charge. Finish: Prime coat--galvanized steel optional. ' "LO-VENT" ROOF VENTILATOR Designed to hug roof and be inconspicu ous. For buildings with pressurizing ventilating systems--propeller fans may be added. Body: galvanized steel--cover hinged. Back Pressure Dampers: aluminum blade. Bird Screen: over exhaust openings on four sides. Louver Control Damper: optional for in side curb. Vent Grille: By others if desired--may oe placed under curb, oizes: 8 to 42 in. square standard-- special sizes optional. 1215 Air Conditioning |SXfwSSr" American Furnace Co. 1300 Hampton Ave., St Louis 10, Mo. Factory--Red Bud, HI. Home Office--St. Louis, Mo. Manufacturers of Cooling and Warm Air Heating Equipment Distribution and Sales Offices in Principal Cities GAS - OIL - COAL FIRED HEATING UNITS - YEAR AROUND AIR CONDITIONING UNITS AIR CONDITIONING UNITS--Comfortmaker--complete year around air con ditioning--Gas fired heating to 135,000 Btu input--Sealed unit cooling--2 find 3 tons--a compact unit requiring minimum floor space. Cooling and blower units in 2, 3 and 5 ton sizes. Custom built heating and cooling units combining AFCO Master Gas or Oil Master heating with 3 or 5 ton AFCO cooling within a single package. Gas fired sections A.G.A. approved. Cooling sections adaptable to existing warm air heating systems. Comforfmoker Combination Heating A Cooling Oil Fired . . . Horizontal Go* Fired. .. Horizontal Oif or Gas Fired Modern Air SPACE HEATERS--Suspended ceiling units for industrial and commercial installations--oil or gas fired. Space saving automatic heat--no furnace room needed. Ratings up to 210,000 Btu out put. Two sizes--oil input 1.35 gph and 2 gph. Unit Heater--A.G.A. approved--Gas fired--vented--propeller fan forced air type modemly styled, die formed, welded steel cabinet--baked Hammer- loid finish. Heat exchange elements hidden from view and touch. Fan se curely mounted at rear. Btu input, 90,000 and 150,000 per hour--air delivery cfm--1400 and 2300. GAS FIRED FURNACES--A.G.A. approved--Gravity, Forced Air, Base-Bio (hi-boy), Counter-Flo and Horizontal Ceiling models. Master Gas heat ex changer--electrically welded rust and corrosion resistant steel--Nationally known controls, double walled Hanuner- loid enamel finished cabinets. Hourly Btu input ratings, 70,000 to 300,000. A.G.A. listed gas conversion units-- single port upshot burners for all type gases. Ratings, 70,000 to 370,000 Btu input--for furnace or boiler installation. OIL FIRED FURNACES--Gravity, Hi-Boy, Counter-Flo Horizontal and Modern Air Units--Qil Master, Vapor- Fire and Air Stream models. Burners--Pressure gun type \and oil vaporizing type. Combustion unit Heavy gage steel, designed for efficient transfer of heat. Cabinets--Double walled construction, finished in two- toned baked Hammerloid enamel. Models available in a range of 75,000 to 250,000 Btu output per hour. Conversion Burners--Pressure gun type --Sizes 75,000 to 588,000 Btu output. Fuel burning capacity--0.75 to 6 gph- SOLID FUEL UNITS--AFCO Gravity and Modern Air (Forced Air) steel units. Btu capacity at registers up to 236,00U Sit hr. . escriptive Bulletin Available on eacn Unit. 1216 Air Conditioning . SSSSSSSSS* E. K. Campbell Co. E. K. Campbell Company Manufacturers targe Manchester at 18th Street, Kansas City 26, Missouri Heating Equipment K.C., Mo. Since 1910 Manufacturers of Heavy Duty Furnaces Standard units up to 8,000,000 Btu per hour District Offices: New Yoke City, St. Louis, Mo., Denver, Colo., Kansas City, Mo Representatives: Minneapolis, Minn., Salt Lake City, Utah, Memphis, Tenn. Custom equipment for engineered applications--units from 400,000 to 8,000,000 Btu per hour output--any required duct-outlet arrangement--equipment component O' Jb arrangements extremely flexible--bal anced job design, blower and furnace sized separately--available in any fuel, stoker Jr fired model illustrated--large air volumes at low temp, rises up to 84 per cent opera ------------------- ------ . DESIGN 20-TYPE H-D FURNACE ting efficiencies--normally shipped K-D standard equipment for engineered application--available for installation in any position m capacities from 400,000 to 8,000,000 Btu per hour output--requires sepa- re blower equipment--highly compact heavy duty furnace of high operating ~~le"?y UP to 84 per cent--available in any fuel except coal--normally shipped assembled. Available for special air volumes if required. DESIGN 30-TYPE H-D FURNACE. Standard equipment, industrial type direct fired heater-- available from 400,000 to 2,000,000 Btu per hour output-- available in vertical, horizontal and inverted models--pro vides maximum compactness--available for single or multiple unit installations--equipped with burner, induced draft fan, and controls mounted and wired at the factory. __ Used in thousands of large buildings over the country, Type H-D furnace equipment is particularly suited for public struc tures such as schools, churches, municipal auditoriums, etc., and for industrial plants such as factories, hangars, ware houses, etc. All Type H-D furnaces are heavy duty equipment of high quality--extra heavy welded steel construction for durability--baked enamel exterior finish on all units. All manocdeeolsf sfluueppglaiesdesw. Litohwinsdtauctiecdprdersasfutrefadnr.oLpoawcroinstseernqauliprmeseinstt. Permanently smoke and gas tight. High operating efficiencies (up to 84 per cent) with resultant fuel economy--true counter flow heat transfer. For further information see your Consulting Engineer or write to E. K. CAMPBELL COMPANY, Kansas City 26, Missouri. 1217 Air Conditioning . gS3S3tg&, Campbell Heating Co. 3121 Dean, Des MoinesT?, Iowa WINTER-CHASER AIR CONDITIONING SYSTEMS EASTERN REPRESENTATIVE: Nbl Adams, 22 Jettebsox St., Lxmbebtville, N. J. Tel. No. 665 HEAVY DUTY HEATERS For Large Churches, Schools, Commercial & Industrial Buildings H SERIES Otl & Gas Fired 75 Heating Guarantee If the heating plant design is approved by our Engineering Department 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 75 in the coldest and windiest weather. 10 Year Durability Guarantee All Campbell Heaters installed as de scribed 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 man ufactured by us carry their manu facturers' guarantee of one year against defects. 8000 SEB1BS For All Fuels HALF SERIES Stoker or Hand Fired Engineering Service Our Engineering Department will be glad to help solve any heating, ventilat ing or air conditioning problems or help with layouts and specifications for any large building. Our Engineering Depart ment consists of trained graduate engi neers backed by 60 years of practical experience. 1218 Campbell Heating Co, Air Conditioning Industrial Heating; Direct-Fired Heaters SPECIFICATIONS and DIMENSIONS Unit No. Btu Heat- per BLOWER! Output ing Sq Ft Normal Capacity Sur Heat cfm Btu/Hrt face ing 135" Sq Ft Sur Dischg. face Temp. Assumed External Static In. Water Motor hp MAX. FUEL RATE Oil gph 1000 Btu Gas cfh LP Gas gph Coal Lbs. per Hr ."S? a in. 1a* -2 in. .e o in. H Series Oil & Gas Fired for Large Residences, Small Churches, Schools, Etc. H200 H250 H300 H350 H400 H500 II600 H700 200,000 250,000 300,000 350,000 400,000 500,000 600,000 700,000 100 2000 125 2000 136 2200 152 2300 167 2400 200 2500 240 2500 280 2500 2600 3300 4000 4600 5300 6600 8000 9200 X X X X X X X H X 1.8 250 2.5 X 2.2 312 3.1 X 2.7 375 3.8 1 3.1 437 4.4 1 3.6 500 5.0 1 4.5 625 6.3 ix 5.4 750 7.5 m 6.3 875 8.8 52 75 57 85 61 87 50 61 87 61 87 . 74 91 60 72 97 72 104 80 8000 Series Oil, Gas, Stoker or Hand Fired for Large Schools, Churches, Etc. 8075 8100 8125 840.000 960,000 1,080,000 280 3000 11,000 320 3000 12,500 360 3000 14,100 1 3 7.5 1050 10.5 100 93 134 76 3 8.6 1200 12.0 114 95 153 76 3 9.7 1350 13.5 129 97 171 76 8150 Sl'/b 8200 1,320,000 1,440.000 1,800,000 440 3000 17.300 480 3000 18,900 600 3000 23,600 5 11.8 1650 16.5 157 98 195 76 5 12.9 1800 18.0 171 99 202 76 5 16.1 2250 22.5 214 120 216 94 8250 2,250.000 2,700.000 750 3000 29,500 900 3000 35.400 1 1 7V* 20.1 2810 28.0 268 120 243 94 7X 24.1 3380 33.8 320 132 251 104 3,150,000 1050 3000 41,300 10 26.1 3940 39.4 375 150 251 114 Half Series Stoker or Hand Fired for Small Churches, Schools, Stores, Etc. 930K sratiyt 940 Vt 944^4 310.000 363,000 399.000 435.000 486,000 104 3000 121 3000 133 3000 145 3000 162 3000 4050 4750 5200 5700 6350 X X X X H X H 1 IX 1H 37 60 72 43 60 78 92 48 60 82 92 52 60 86 92 58 60 90 92 Rectangular Tube Radiator 9445 9485 537.000 179 [ 3000 550.000 183 I 3000 7000 [ 7200 j X H 64 I 60 I 92 | 92 66 | 60 | 96 1 92 8000 Series Unit Heater--Oil, Gas, Stoker or Hand Fired--for Large Industrial U8075 U8100 U8125 U8150 U8175 U8200 U8250 U8300 U8350 Buildings 280 3000 11,000 2-X 320 3000 12,500 2-44 360 3000 14,100 Engineers 2-1 7.5 1050 8.6 1200 9.7 .1350 10.5 12.0 13.5 100 114 129 93 80 95 93 97 105 76 70 76 440 3000 17,300 480 3000 18,900 600 3000 23,600 if duct system 2-m 2-H4 2-2 11.8 1650 16.5 157 12.9 1800 18.0 171 16.1 2250 22.5 214 98 118 99 130 120 137 76 76 94 750 900 1050 3000 3000 3000 29,500 35,400 41,300 is to used. 2-3 2-3 2-5 20.1 2800 28.0 268 120 157 94 24.1 3380 33.8 320 132 157 104 26.1 3940 39.4 375 150 157 114 for nielr... li l"erm,al efficiency for oil and gas anda 7nr/o lor coai. aqo iuy0 to ddy0u outumuM uea* mew - stine a<* Fo?JtS?my tnd life of to 15% for duct the equipment. radiatio--n losses. The hig'her fig" ure is preferable for best oper- ir volumes and static pressures consult our Engineering Department For Complete Specifications, See Sweet7s Catalog Service 1219 Air Conditioning Chicago Steel Furnace Co. 9326 S. Anthony Ave., Chicago 17, 111. Manufacturers and Designers Artcraft Heating & Air Conditioning Equipment DIRECT-FIRED SPACE HEATERS 350,000 Btu to 2,000.000 Btu UNIFORM AIR DELIVERY BLOWERS--Three standard up-blast discharge, multi-vane Blowers, each in dividually powered, are provided to sup ply the correct amount of air to properly cool the Heat Exchanger. Individuallydriven Blowers are used because of the great flexibility of operation obtainable. Uniform bonnet temperature may be enjoyed by the simple expediency of in creasing or reducing the amount of air driven around any particular section of the Heat Exchanger. Performance Data Direct Fired Model A Units MODEL AIR DEL CFM 3000-4200 6000-7800 8200-6600 12500-15500 15000-17500 17500-21000 21000-24000 L 72 92 100 114 124 128 144 W 40 42 50 54 56 62 66 99 no 114 115 125 ARTCRAFT SUSPENDED UNITS Fired with Gas or Oil Ratings and Specifications Suspended Units OUTPUT AIR DEL MODEL BTU CFM-VS.P. 75-S 75-SL 100-S 200-S 250-S 350-S 400-S 750-S 85,000 85,000 100,000 150.IKI0 200,000 250.000 350,000 400,000 500,000 750,000 800-1000 800-1000 1000-1600 1200-2000 2200-2600 2400-3200 3000-4200 4200-5200 4600-6200 8200-9600 L 63 78 76 79 86 90 104 107 114 146 W 24 22 24 31 31 35 40 42 45 52 1220 Factory Installation Model 100S-& Air Conditioning Direct Fired Heaters HEATING CORPORATION 1 Cole St., Trenton 8, New Jersey Manufacturers of Unit Heaters, Suspended Horizontal Furnaces, Floor Furnaces, Winter Air Conditioners, Gravity Furnaces and Counterflow Furnaces. Representatives in all principal cities. Io Canada--Kresno-Stamm, Montreal 24, Quebec DIRECT FIRED OIL UNIT HEATER FREE AIR DELIVERY - NO DUCTS REQUIRED - ADJUSTABLE LOU VRES - DIRECT HEAT WHERE NEEDED Cutaway Vieu? For Factories, Warehouses, Multiple Unit Installations, Small spaces, Tempo rary buildings. Outside loading plat forms, Chemical Plants, Woolen, Textile and Wastepaper plants. Stores, Restau rants, and Commercial Buildings Fired with a conventional gun-type oil burner, this unit is ideal for locations re quiring high air delivery. Outstanding features include a vertical flue travel which permits the exhaustion of com bustion products through a short flue pipe without the use of a high-draft chimney. The UH-220 becomes an effective summer air circulator and ventilator. For applica tion in locations where humidity should be increased. Delta includes an automatic humidifier as an accessory. . The burner and flue outlet can be attached to either side of the housing which measures 49J^ in. high x 39 in. wide x 21 in. deep. Heat output is 220,000 Btu/hr hred with a 2 gal/hr nozzle. A large >4 hp propeller fan and motor "throws" the heated air for an effective distance of 50-75 ft. Air delivery rates 5,730 cfm. Mounting is by overhead suspension or by setting upon a platform or dolly in temporary loca tions. Factory pre-wircd and assembled. . DELTA OIL-FIRED SUSPENDEDHORIZONTAL FURNACE FOR INSTALLATIONS REQUIR ING DUCT WORK TO HEAT VARIOUS CLOSED-IN AREAS. lor Narrow Crawl Spaces, Temporary Heating, Homes, Factories, Commercial Buildings, Gas Stations, Paint Dry Ovens, Restaurants, Hothouses, Humidity Control, Showrooms, Tobacco Curing, and Warehouses. , e versatile Suspended-Horizontal Furnace is available in 4 sizes with heat fr lPu'lof ^0,000, 110,000, 160,000 and 210,000 Btu/hr. Adjustable blower capacity Tt 8(S'-1000> 900-1200, 1900-2200 and 2500-2800 cfm. sus "e | "8 an<J Slf-110 are only 20 in. from top to bottom--shallow enough to hea^Cn I, 0,fU t^1<r way especially narrow attics or crawl spaces. For temporary t, the furnace is placed on a 2 wheel dolly and moved wherever required. ' fhe.iurnaees are economical, ruggedly constructed, factory wired and assembled r quick, easy installation. . 1221 ntf I Hi m- !'i Air Conditioning SreSiSed^HeitOT ft, Dravo Corporation Heating Department ~ Dravo Building, Fifth-&,Liberty-Avenues, Pittsburgh 22, Penna. . - Atlanta, Boston, Chicago, Cincinnati, Cleveland, Dertoit, Indianapolis, Mkw York, Philadelphia, Pittsburgh, St. Louis, Washington Sales Representatives in Principal Cities DRAVO Lounfiftfur SPACE HEATERS 400,000 to 2,000,000 Btu/hr output ECONOMICAL--Low initial cost-- 30-60 percent less than standard wet- ^J type equipment to'install. 80-85 per !p' cent efficient at bonnet . . . burns gasfe or oil, readily convertible from one to ^ the other. ^ EASY INSTALLATION--Just hook up If fuel, electric and exhaust connections-^. --no ductwork required. . ,||| STAINLESS STEEL COMBUSTIONl?f CHAMBER--Rugged mill-type con- m struction . . . top quality engineering. Exhaust whirl-cooled through two sets of economizer tubes. SAFETY-TESTED--Approved by A.G.A. and listed by Underwriter's Laboratories, Inc. Dravo Safety Con- g trol Circuit is accepted by Factory|| Mutual Engineering Division andjjs Factory Insurance Association. Dravo Counterflo Space Heaters in addition to comfort heating are easily adapted to heat curing and process drying, temper ing of replacement air and summertime ventilation. Dravo Counterflo Space Heaters can also be tied in with air condi tioning systems. COUNTERFLO Htr. No. 40 50 75 100 125 150 175 2(10 Output CFM Temp. Btu/hr at- iUT7 Rise 400,000 4500 500,000 5500 750.000 8500 1.000.000 11,000 1.250.000 14,000 1.500.000 17,000 1,750,000 19,000 2,000,000 22,000 S2 84 82 84 83 82 85 54 Efficiency Fan Approx. Mtr. Nozzles Shpg. hp wt. Dimensions ' L W H$ 80% 80% 80% 80% 80% 80% 80% 80% m 2 3 5 10 is 20 3 3 4 4 4 4 4 4 1500 1600 2600 2700 3600 3800 4300 4500 4'ir 4'H" 7'3" 7'3" 811" s;ij' 95 9'5" 2'7" 2'7" 3'8" 3'8" 4'3" 4'3" 4'9" 4'9" 7'0" % /u 8'8" ;.y 38 y8 9 8 b :jf lull. lO'll 4 ' r PARAFLO * 1 20 200.000 2200 84 25 250,000' 2700 84 80% 80% 1222 2 2 710 4'1K" 2'5" ?'9k; # 730 4W 2'5" 7'9M, y Dravo Coup. Air Conditioning Industrial Heating; Direct-Fired Heaters DRAVO tPffla/fo SPACE HEATERS 200,000 to 250,000 Btu/hr output POWER AND FUEL--Heater operates on 110 volt, 60 cycle, single phase power, and burns up to and including No. 2 fuel oil. . FAST TRANSFER OF HEAT--Stainless-steel combustion chamber allows faster heat transfer from fuel to air and guarantees longer heater life and sustained efficiency. Equipped with UL approved gun-type oil burner. FLOATING COMBUSTION CHAMBER--Supporting straps hold stainless steel chamber in place for inverted or hori zontal mounting. One end floats freely relieving stresses and strains due to normal expansion of chamber. . HEAT ANY DIRECTION--Warms areas up to 3600 sq ft. Directional nozzle can be rotated 360 heating any desired location, high velocity discharge assures good distribution up to 90 ft from the unit without the use of ductwork. This new Dravo heater is ideal for garages, service stations, construction offices, recreation centers, agriculture buildings, warehouses, stores, offices and showrooms. The heater fan can be used for summer ventilation. Heaters can be adapted to air conditioning systems. See data chart on opposite page. DRAVO /=ukeaf SUSPENDED TYPE UNIT HEATERS 68,000 to 180,000 Btu/hr output RUGGED CONSTRUCTION--Heater is a durable unitjwith a cast iron heat exchanger, cast iron burner, and a heavy-gauge steel exterior jacket with baked enamel finish. EASILY HOOKED UP--Delivered completely assembled. Just connect gas piping, electric line and exhaust stack. Units wall hung or suspended from roof trusses to conserve valuable floor space. EFFICIENT--Minimum heating efficiency 80 per cent. Built in draft diverter. . Complete range of models: Heaters are available with either propeller fan for free ^charge or blower type fan for ductwork; without fan for duct furnace application where air is supplied from separate source (some models only). Each model capable of 'ru natural or manufactured gases in all size ranges. A" Dravo Gas-Fired Suspended-Type Heaters can use natural, manufactured, mixed, butane, sewer, or propane gas and liquified petroleum. Give low cost space neating commercial and industrial buildings such as garages, stores, machine shops, warehouses, amusement centers and other buildings. SUSPENDED GAS FIRED MODELS oizes and Capacities--Propeller Type*--Series DE Model Output CFM at Btu/hr. 70*F Approx Temp. Minimum Motor imate Rise Effic. hp Shipping 68,000 88,000 112,000 128,000 160,000 180,000 1350 1820 2320 2600 3200 3500 46.5 44.7" 44.7 45.7 46.5* 47.5* 80% 80% 80% 80% 80% Vio Ho Vi y* H 300 350 400 450 525 525 hor*^!Liype j nl*? aYa`lable in same sizes, however cfm and motor and power and shipping weight may vary. --and Capacities--Duct Type*--Series 120DD 9~6-.-0--0-0--------8-7--5---1--2--7-0------1--0--0-*-F---------- --80--% ----------- 160DD 70*F 128,000 1280-1830 100*F- 80% -- 200DD 70"F 160.000 1600-2280 100*F- 80% 70"F DD 435 500 585 Saginaw, Michigan "Work well done since '81" SUSPENSION FURNACES Ideal for residential, commercial or in dustrial heating, these J-C designed and engineered suspension units save valu able floor space. Comfort and perform ance plus long life with features that include: 20 gage rust-resistant steel cabi nets and liners, 12 gage steel heaters, proven J-C designed stainless steel com bustion chambers assembled in oil fired units. Grey hammertex baked enamel. J-C Suspension Units, in factory assem bled packages, require a minimum of installation time. Gas or oil fired. 80,000 to 1,000,000 Btu output. 1010 cfm to 12,500 cfm bonnet. POWERAIRE FURNACES J-C Poweraire Series for larger homes. Incorporates famous J-C leakproof welded construction in an enclosed, mod ern cabinet. Casing and liners are. of rust-resistant steel. Grey hammertex enamel. Economical, automatic . . . the Poweraire Series is J-C engineered for comfort and plus performance. Gas or oil fired. 152,000 to 320,000 Btu output. 1910 cfm to 4020 cfm bonnet. POWERATED* SERIES For the largest commercial and indus trial installations. J-C PoweRated Se ries is specifically engineered for heavyduty heating requirements such as: industrial ventilation where outside air is introduced and tempered to working requirements; industrial heating and cooling; industrial processing and dry ing. Begins where most warm air heat ing lines leave off! Up to 3,800,000 Btu output. Cfm bonnet --as specified. * Designed to fit the job . . . provide specific Btu output to meet big requirements. - 1224 Suspension Series Poweraire Series PoweRated Series -V >'! ` -;Vv. & V-vf.r JjU Air Conditioning Automatic Equipment; Direct-Fired Heaters. Unit Heaters Lee Corporation 1011 Tatnall Street, Wilmington, Delaware Baltimose. Mo. New Yobk, N. Y. Representatives in all Principal Cities Chicago, III. Manufacturers and Designers of Complete Line of Industrial and Commercial Warm Air Heaters MODEL UD--300,000 to 2,000,000 Btu MODEL TSE--2,000,000 to 8,000,000 Btu MODEL VTH--2,000,000 to 6,000,000 Btu MODEL BST---2,000,000 to 10,000,000 Btu LEE HEAVY DUTY HEATERS Lee Direct-Fired Space Heater Model hd 300,0C0 to 1,000,000 Btu LEE HEATERS have been in continuous operation since 1918. Lee Heater in stallations have been made in most of the States of the United States, in Canada, Alaska, Yukon Territory, Northwest Territory, Labrador, Iceland, Norway, Mexico and South America. Firing Equipment manufactured spe cially for us by leading Companies with International service organization. There is a Service man near you if and when you require assistance. In addi tion Lee maintains a competent field serving staff. Replacement and Spare Parts Service is maintained. Most items are carried in stock. Heater Number output Capacity (Btu per hr) iotal Heating Surface in sq ft Ertemal Static Pressure (Std ) Maximum External Static Press Available for Duct Work (larger Motor Required) Shipein Weight (Approx.) Lbs Refractory Comb. Chamber Stainless Steel Comb. Chamber 300 . 300.000 92 3500 . r- 400 400,000 ' 106 4500 !* r 79 380 2.6 3000 2100 82 500 3.5 3100 2200 500 500,000 126 6000 Y V 77" 630 4.3 . 3300 2400 600 600,000 202 7000 3; P. 79 750 5.2 4500 4000 750 750.000 235 8500 .5 Y 1* 82 940 6.5 4700 4200 ~ Lee Heater Numbed Output Capacity (Btu per hr) Total Heating Surface in sq ft Cu ft of Air per min. (AppTOX.)* Fan MotoT hp Externa) Static Pressure (Std.) Maximum External Static Press. Available for Duct Work (Larger Motor Required) Temperature Rise (Degree I Fuel Consumption** * F) A-cu ft Gas per hr. (App.) E-gal Oil per hr. (Approx.1 Shipping Weight (Approx.) Lbs Refractory Comb. Chamber Stainless Steel Comb. Chamber **BS?r" Standa.rd Air at 70 F Free Delivery, 1,000 1,000,000 278 11,500 5 Y 1* 1250 8.6 ` 6000 5200 1250 1,250,000 333 14,000 1' 1560 10.8 5500 1500 I 1750 1,500,000 375 17,000 10 Y 1,750,000 423 20.000 15 i: 1880 13.0 7500 6200 2190 15.0 2000 2,000,000 470 22,000 15 2500 17.2 ciency for ttah^ter011 Based on 1000 Btu per cu ft Gas, 145,000 Btu per Gal Oil, and on 80 per cent Effi- 1225 . :! MODEL "H"--EFFICIENT--Produces p controlled heat at 80 percent operating efficiency in factories, foundries, ware- '||? houses, garages, hangars and terminals. Designed to burn gas, oil or combination fuels. Available in ceiling suspended, |g' inverted and portable units. ECONOMICAL OPERATION--Circu- J| lates warm air at working levels, keeps roof heat loss at a minimum. Low initial -||r; cost--no boiler house or power piping ^5 required. Low operating cost--standby losses eliminated, no licensed attendant ||.- needed. . TESTED CONSTRUCTION--Features stainless steel firebox in efficient teardrop ;|x- design. Completely automatic in opera- ^ tion, fully self-contained, easy to install. Separate induced draft blower. All equipment wired and fire tested at the factory to assure dependable, enduring service. Underwriters* Laboratories listed. 34 w Heater Number TD-20 TD-25 TD-30 TD-40 TD-50 TD-70 TD-80 TD-100 TD-125 TD-150 TD-175 TD-200 Btu Output Capacity 200,000 250.000 300,000 400,000 500,000 750,000 800.000 1,000,000 1,250,000 1.500,000 1,750,000 2,000.000 CFM at H in- S.P. HP Blower Motor 2,400 3,200 4,000 5,400 6,600 8,800 10,200 12,500 15,300 19,400 22,000 26,000 H H y* 1 IX 2 3 5 5 m TX 10 1226 Overall Dimensions Width 28 28 32 32 32 32 48 43 54 54 60 60 Length 52 52 60 60 80 80 80 80 100 100 120 120 Height 66 66 81 81 81 81 81 81 98 98 98 98 Shipping Weight 950 1020 1250 1360 1600 1850 2310 2680 3155 3340 4300 4500 Air Conditioning Direct-Fired Heaters Arthur A. Olson & Company Canfield, Ohio Manufacturers of Direct Fired Heaters ` ( A completely automatic direct-fired unit heater. Olson heaters operate on gas, oil, dual gas-oil or coal. These units may be hung, suspended horizontally or inverted. All heaters can be adapted to filtering, humidifying and air conditioning. Use of standard accessories and easy access to bearings and other vital parts simplify main tenance. Also special adaptions for make-up air, drying, high-temperature and process work. 1. Standard 10 Gage Boiler Tube Heat Transfer Surface. 2. Stainless Steel or Refractory Combus tion Chamber. . 3. Heavy Duty Fans and Shaft. 4. Inlet Screens or Frame for Filter Box. 5. Adjustable, Deflecting Outlets. 6. Separate Induced Draft Fain. 7. Bearings Outside Heater at End of Shaft. Four Pata Goa Tmvcl-Counter Current. Engineering Data--Gas, Oil. or Dual Gas-Oil Heaters. Heater Model Number BTU/HR Output Capacity ~B5oo~ U-400 U-500 U-600 JJ-750 U-1000 U-1250 U-1500 Jl-1750 U-2000 1 400.000 500, COO 600.000 750.000 1.000,000 1.250.000 1.500.000 1.750.000 2.000.000 1 CFM Blowing A 3.500 V- 1' 4.500 3'- r 5.500 3'- r 7.000 v- \m 8.500 3'- 8' n.ooo 3'- 8* 14.000 4'- 4" 17.000 4'- 4' 20.000 , 4'-J0' 22.000 1 4'-10* Genera! Dimensions B 2'-ir 3'- 7* 4'- 3' 4'-ll' 5'- 3* 5'-lI' V- O' 8'- 0* 8'- 0' 9'- 0' C 7'-I0' 7'-ny 7'- 3' 7'- 3' 8'- 9* 8'- 9' 9'- 9' 9'- 9' 10'- 9' 10'- 9' Cl i'-r r-i* r-3' r-r r-i* r-3' l'-6' r-6' r-5' I'-5' D 1'- 6' r- 6' r- 7' r- 7' r- 8* r-ii' r-ii' 2'- O' 2'- r V- 1' No. of Blow- ing Fans Motor HP Blowing Fans 1 1 1M 22 23 23 25 2 7H 2 10 2 15 2 15 Stack 8' 8' 8' 8* S' lO' 10* 12* 12* 12* Write for complete data on stoker fired units and large central systems. No. of Nos- Out- 2 3 3 4 4 4 4 5 5 S 1227 - Air Conditioning dSihSot ' Division ~ Prat-Dauiel Corporation Meadow Street S. Norwalk, Conn. THERMOBLOC DIRECT-FIRED, SELF-CONTAINED INDUSTRIAL UNIT HEATERS Complete Range of Sizes 100.000-200,000-300,000500.000-800,000^1,000,000 Btu output Model 300 Model 300 THERMOBLOC saves you more money by more effectively utilizing the econom ical principles of direct-heat transfer. Low in first cost, easy to install, THERMO BLOC needs no special foundation, no expensive piping, radiation and duct work. A real "fuel miser," its operation at 82 per cent to 86 per cent efficiency means you get the most from your fuel dollar throughout the years, . .and because it is fully automatic, THERMOBLOC needs no attendant. THERMOBLOC provides a wide variety of units, combinations and multiples which can conform to the exact heating requirements of any plant, regardless of size or shape. This THERMOBLOC flexibility makes possible the economical heating of plants that present problems which often cannot be solved with cither types of heating equipment. By placing THERMOBLOC in a strategic position and adjusting the louvers, any amount of heat can be furnished where required--at floor level and not in the ceiling. . .Sturdy, boiler-like construction of combus tion and heat-transfer surfaces and the use of nationally known, dependable controls, burners and fans make THER MOBLOC a unit that will give you reliable, long, trouble-free service. For better heating buy THERMOBLOC ' Send for your THERMOBLOC Bulletin NGC-10-52 today! Packed with information, including many application photos. Write today for your copy! 1228 Air Conditioning Direct Fired Unit Heaters aiid Coolers Airtherm Manufacturing Company 728 S. Spring Ave. St Louis 10, Mo. Representatives in Principal Cities For Heating Satisfaction-Think first of AIRTHERM Vertical Boricontal AIRTHERM Steam Unit Heaters, - Horizontal and Vertical Discharge Horizontal models are produced in ca pacities from 18,000 to 270,000 Btu. Ver tical models 32,000 to 350,000 Btu per hour. Write for Catalog 1209. AIRTHERM Gas or Oil Fired Space Heaters A complete heating, and heating and ventilating unit. Equipped with motors, burner and all safety and operating con trols. Easy to install and operate. Heavy duty steel combustion chamber lined with castable refractory. Capacities from 650,000 to 2,000,000 Btu per hour. Write for Catalog 802 B. AIRTHERM Gas Fired Unit Heaters Efficient answer to heating needs where there is no steam supply. Compact, sus pended, propeller fan units available from 25,000 Btu to 200,000 Btu. Write for Catalog BOO, AIRTHERM Convectors Airtherm Convectors are designed for easy installation and outstanding per formance. Copper coil for all hot water and two pipe steam systems. Produced *2} full range of types and sizes. Write for Catalog 702-A. AIRTHERM Centrifugal Fan Unit Heaters For all types of heating, and heating and ventilating installations, in industrial and commercial buildings auditoriums, gym nasiums, schools. Available with dam pers, filters and non-freeze coils. Ca pacities up to 1,440,000 Btu per hour. Write for Catalog 403. Air Conditioning iiec. Automatic Gas Equipment Company Brushton and Thomas St., Pittsburgh 21, Pa. Manufacturers of Pittsburgh Gas Unit Heaters and Duct Furnaces Cast Iron Heating Elements Cast iron is considered to be the best material to withstand the corrosive effects of the products from combustion of gases. For this reason, both the heat exchanger and combustion cham ber in a Pittsburgh Gas Unit Heater are made, of cast iron. Furthermore, they are cast in one piece and the ex tended heating surface fins on the heat exchanger are cast integral. Pittsburgh Gas Unit Heaters have been designed to consume exactly the right amount of air to support complete combustion but without permitting an excess of air to lower heating efficiency. This is accomplished by means of a built in draft hood which absorbs all excessive chimney action and thereby conserves heat. The heater does not depend upon forced draft from the fan for either the primary or secondary air supply. For this reason there is no possibility of variation in the air supply to the burners resulting from changes in fan speed or louver adjustment. By the use of adjustable horizontal louvers, warm air can be directed to any desired level. Safety Features A tested and proved safety pilot is used on these heaters to automatically turn off the gas if the pilot light goes out or if it burns too low to insure posi tive ignition. The draft diverter is absolute protection against any possible down drafts through the chimney. Write for folder containing complete details, including installation measure ments. Approved by American Gas Associa tion and Underwriters' Laboratories. Cut-owap view oj healer showing the cast iron heal exchanger in place. Heal exchanger and combustion chamber. SIZES AND CAPACITIES (also made in five sizes in Blower Type Units) Unit No. 215 C 175 C 160 C 140 C 110 C 85 C Input B.T.U. Per Hour 215,000 175.000 160,000 140,000 110,000 85.000 Output--AGA B.T.U. Per Hour 172,000 140.000 128,000 112,000 88,000 68.000 So. Ft. ED.R. 744 605 553 484 381 294 Air Del. C.F.M. y*3500 2900 2600 2320 1820 1350 Motor H.P. i 1 1 A *0 DO Speed R.P.M. 1140 1140 860 860 860 1000 Approx Wta. 525 Air Conditioning Unit Heaters and Coolers Fedders-Quigan Corporation . Heating Division Hancock & Lalor Sts., Trenton 7, N. J. FED DEE S Manufacturers of Convector-Radiators, Wall Radiation, Baseboard Radiation, Unit Heaters, Railroad Car Convectors, Unit Coolers, Refrigeration Coils, Air-Cooled Fin and Tube Condensers, Clip-on Thermometers, Room Air Conditioners, Auto motive Radiators, Car Heater Cores, Dehumidifiers. Feiders Series 17 Hori zontal Unit Heaters made in capacities from tlO- USS EDR. >. Feiders Series 16 DownHow Unit Heaters' for high or low ceilings and spot locations. Capacities from 155-S050 EDR. Feiders Series 18 GasFired Unit Healers in eight sizes--183-667 EDR. FEDDERS UNIT HEATERS Made in horizontal and 'downblow types. Well graduated range of capacities to fit requirements. Quick response to manual and thermostatic controls as sures comfort and fuel economy. Com plete data given in catalogs. FEDDERS CONVECTOR RADIATORS Complete line for standard and special applications. For use with steam and forced or gravity hot water systems. Widely used for new and modernization work. Write for catalog giving complete data. FEDDERS BASEBOARD RADIATION FEDDERS WALL RADIATION omplete line for semi-recessed and ush-mounted residential and non-resi- ential installations. Available with cop For industrial, commercial, institu tional and household use. Rugged, all Per aluminum or steel heating element, steel heating elements available with ex ivaP n ^es'8n uts installation time. panded mesh or solid front, flat or sloping " nte for catalog. top enclosures. Write for catalog. 1231 Air Conditioning Dmt Heaters-" GRINNELL COMPANY, INC. Heating, Power and Process piping. Pipe Hangers, Pipe Fittings, Welding Fittings, Valves, Unit Heaters, Piping Supplies Executive Offices: Providence, R. I. Branch Offices in Principal Cities of United States and Canada GRINNELL UNIT HEATERS THERMOLIERS FOR STEAM (OR HOT WATER) Thermolier Unit Heaters maintain rated capacity because their pitched U-tubes and internal cooling leg prevent collection of condensate in the heating element. In fact, condensate cooling is so efficient with Grinnell Thermoliers that a thermostatic trap--the simplest and least expensive of all traps--Can be used with every model. . Textile Thermoliers maintain maxi mum capacity by means of a special heating element consisting of a series of webbed, pitched U-tubes, parallel to one another and assembled into a sin gle header. Absence of conventional fin edges minimizes the collection of lint, fly ash and dirt on the heating surfaces. Parallel openings between the webbed tubes permit air from the fan to pass through the entire heating element. The vertical delivery Thermolier delivers heated air directly downwardIn normal operation the heated air would blanket a circular area. In large areas of single story construction, - an ideal heating system would utilize vertical delivery Thermoliers for the central portion of the area and horizontal de livery Thermoliers to blanket the ex posed walls. GAS-FIRED (FOR ANY TYPE GAS) Grinnell gas-fired unit heaters are easy to install, operate and maintainEfficient performance is assured--wile any type of gas--by modern design ot burners and heat exchanger, proper motor and fan unit. Automatic safety pilot operates to shut off main ges supply if pilot goes out. Flash bacx and extinction noise prevented by tn? burners' raised port design and proper port size for the gas used. Low speea motors have built-in thermal overloao protection and automatic reset. 1232 Grinnell Company, Inc. Air Conditioning vnB Heaters CAPACITIES--GRINNELL UNIT HEATERS CTP A1VT* Based "on Standard Basis of Rating (2 lb Steam Pressure and 60 deg O 1 E,r\ivx En1.eYing Air Temperature) Horizontal delivery models--for constant speed operation, use bold face figures only . --for two speed operation, use both figures model rpm at normal speeds total heat delivered Btu per hr equivalent direct radiation edr cfm at exit air. temp D21 D31 1725 1250 1725 1250 35,600 29,700 48.700 38,400 :. - 148 124 203 160 637 482 689 513 D37 D41 D44 D57 1140 950 1725 1250 1140 750 1140 875 62,200 54,200 71,000 56,000 84.100 63.000 101.300 84,400 259 226 295 233 350 262 4 22 352 1062 874 1271 914 1250 852 1433 . 1127 D66 D71 D91 1140 .760 1140 690 1140 690 128.700 103,000 151.700 111,600 196.000 137,100 536 2166 375 1572 632 2716 423 1744 817 2738 532 1702 Dill 1140 640 275,300 195.7(H) 1147 815 5095 3342 Capacity tables for hot water Thermolier on request. Textile models--constant speed operation exit air temp F conden sation lb per hr 116 122 133 138 119 123 116 122 129 137 133 . 138 120 127 116 125 134 145 114 119 37 31 50 40 64 56 73 58 87 65 105 87 133 107 157 115 203 ; , 142 285 203 air velocity at esit-- tinear ft per i louvers wide open louvers set at 45* velocity nozzle max 786 595 851- 633 912 690 ' 987 734 1336 1011 1447 1076 753 620 901 648 887 604 1016 799 779 556 977 . 628 985 612 949 781 1135 816 1118 761 1280 1007 982 712 1231 790 1241 771 1160 955 1388 998 1366 930 1565 1230 1332 967 1671 1072 1684 1048 1048 688 1415 929 1803 1183 model rpm at normal speeds total heat delivered Btu per hr equivalent direct radiation edr cfm at exit air temp exit air temp P TX70 1140 69.800 291 2297 TX110 1140 113,700 474 2438 Textile Thermolier not available for hot water systems. 89 106 conden sation lb per hr . 72 118 air velocity at exitlinear ft per min louvers wide open louvers set at 45* velocity nozzle max 826 1041 1412 877 1105 1500 Vertical delivery models--for constant speed operation, use bold face figures only __ ______ < . --for two speed operation, use both figures model rpm at total heat normal delivered speeds Btu per hr equivalent direct radiation edr cfm at exit air temp exit air temp *F condensa tion lb per hr air velocity at exit ft. win, 1725 50.800 212 1483 93 53 1399 VA1D45 1250 1725 40,100 73.600 167 307 T078 1363 96 114 41 1017 76 1287 VA1065 1250 1140 59.900 109.400 249 456 995 2869 121 97 62 939 113 1354 VA1075 690 1140 80,000 145.600 ' 310 607 1786 2609 104 116 83 842 151 1231 VA1101 690 1140 101.900 185.000 392 770 1557 4510 127 100 105 734 191 1495 VA1111 600 1140 122,000 257.000 508 107! 2517 4921 108 112 126 835 266 1631 640 187.000 729 3105 121 194 1030 . GAS-FIRED Orders must specify heat input, type of gas, its heating value in BTU per cu. ft. . model no. _ GF20Q " Btu/hr input 25,000 50,000 130,000 170,000 output 20,000 40.000 60,000* 80,000 104,000 136,000 I1U6U0,,0U0W0 cu ft of air per min 400 650 1000 1200 1700 2500 t2W90U0lj final temp F*f 124 137 126 132 127 121 121 throw, ft (max. under ar*g condi tions) 18 28 33 38 45 50 O56f) fan speed rpm 1050 1050 - 1050 1050 1140 1140 -1144U0 diameter 12 12 16 16 16 18 i2\0) motor hp Mo Ms Ha M t Orf enterin air temperature . Btu/hr. q Ded ^troleum gases and L. P. gas-air mixtures, input is 70,000 Btu/hr and output is 56,000 1233 ILG Electric Ventilating Co. 2880 North Crawford Ave., Chicago 41, 111, Offices In more than 40 Principal Cities ILG UNIT HEATERS--STEAM, HOT WATER, ELECTRIC OR GAS Air Conditioning u^nd^s. KE KennnRD 1819 So. Hanley Rd., St. Louis 17, Mo. Manufacturers of AIR CONDITIONING EQUIPMENT Finned Coils (Heating & Cooling)--Air Conditioning Blower Units--Multi-Zone Units--Heating and Ventilating Units-- Sprayed Coil Dehumidifiers--Cooling Towers -- Evaporative Condensers -- Liquid Chillers Low-Ceiling Type--for mounting where there is little head-room. Side inlets and outlets assure compact installation. Horizontal Type Unit Heaters--have ILG-built Self-Cooled Motor to counter act coil heat--never "slow roasts." Graduated 2-piece, cast iron header gives "balanced" steam distribution. Brass orifice bushings expand tubes uniformly in header plate. Copper fins are pressed into round copper tubes for permanent union--no brazing, soldering, or welding. Bottom header "floats" to permit expan sion and contraction of coil independent of casing. Tested and Rated according to codes of I.U.H.A. and A.S.H.V.E. Ratings certified by I.U.H.A.--"OneName-Plate" Guarantee. Wide range of sizes, capacities. Vertical Type--for installations with ex tremely high or low ceilings. Diffiisej? ? or deflectors available to direct air flow. Textile Type--more tubes, no fins--for., applications where lint, etc., normally, adheres to fin surfaces, clogs up coil. ILG Electric Unit Heaters . Standard Type--for instant, clean, safe, dependable heating- ` Coil is of black heat type which operates below 400 degreesProtected against excessive temperature rise by patented auto matic thermal cut-out and magnetic starter. Sizes 5 to 15 KW- \. Type HT also available in l)- to 4KW sizes. * ILGDUALGAS Unit Heaters ' Suspended propeller fan type, completely self-contained with simplified central control system. Uses natural, manufactured, mixed, propane or butane gas. Capacity range 25,000 to 200,'**'" Btu's. Approved by Underwriters Laboratories and the A.O.A For ILG Propeller and Centrifugal Fans, see page 1335. 1234 AIR CONDITIONING BLOWER UNITS MULTI-ZONE UNITS 13 Sizes. 300 to 21,600 cfm. Horizontal or Sizes up to 36 sq ft. Cooling Coil Face Vertical. Catalog No. AC-1. Area. Catalog No. MZ-1. HEATING AND VENTILATING UNITS Air Volumes 300 to 28,800 cfm, and up to SQ ft Coil Face Area. Catalog No. SPRAYED COIL DEHUMIDIFIERS 56 Sizes. Coil Face Areas up to 81 sq ft. Catalog No. SC-1. COOLING TOWERS AND EVAPORA TIVE CONDENSERS Packaged Economy Line in sizes from 3 to 15 tons. Centrifugal type fan for quiet Indoor and Outdoor installation. Galvanized asphalt and asbestos fibre material. CT model (not shown) fur nished in sizes from 15 to 75 tons. w> up to d6 in '-atalog No. BC-t. LIQUID CHILLERS Direct Expansion, Freon Shell and Tube Liquid Chillers. Internally finned tubing (Pat. Applied For), brass baffles, positive oil return, closed refrigerant circuits without freon gaskets. 1235 Air Conditioning Unit Heaters and Coders "If? McQuay, Inc. 1602 Broadway, N.E., Minneapolis 13, Minn. MANUFACTURERS OF AIR CONDITIONING EQUIPMENT Air Conditioners Air Conditioning Coils Blast Heating Coils Refrigeration Coils Unit Heaters Unit Coolers ` Seasonmakers Cooling Towers Sales Offices in ail Principal Cities PROVEN Htg. & Vent. Units Blower Coolers (Suspended & Floor Type) WM Ice Cube Makers (Auto fUGlj. matic) Icy-Flo Accumulators Zeropak Low Temp. Units PRODUCTS Evaporative Condensers THE EXCLUSIVE McQUAY RIPPLE FIN COILS Heat transfer surface with higher efficiency and greater durability is as sured when you select a McQuay Ripple Fin Coil. ' The expansion of all tubes into fins having wide smooth collars, without the use of any "low conductivity" bonding material, provides a permanent mechan ical bond, for long life high heat transfer efficiency. Ripple fin coils produce a rippled- air flow pattern assuring a closer and longer contact between the air stream and the coil surface, thereby preventing air by pass and producing more rapid heat transfer. Ripple fin coils have higher flexible strength with minimum air friction and cleaner operation. The copper tube headers provide inherent flexibility to accommodate unequal contraction and expansion during operation. Ripple fin coils easily and effectively drain off con densed moisture, with water hang-up being sharply reduced on coils requiring vertical (up) air flow. Ripple fin coils permit increased face velocities without danger of moisture Ripple-Fin CoU carry-over from the fin surface to the air stream. ' McQuay's numerous header sizes and tube lengths provide greater flexibility for sizing jobs. McQuay coils are available in a wide variety of styles and sizes; both standard and special coils for steam, hot water, cold water, brine, direct expansion, re frigerant condensing, and other applica tions. . McQuay coils are proved and preferred --proved by service under the most rigid conditions, and preferred because of their exclusive fin construction. McQUAY manufactures a complete line of Standard Coils for the Industry. Coils for Heating--1 to 10 rows deep using low or high pressure steam or hot water. Jet-Tube (Non-Freeze steam inner tube) type coils 1 and 2 rows deep. Cleanable Tube--Removable plug type water coils 1 to 10 rows deep. Water Coils for Cooling--1 to 10 rows deep. Direct Expansion Coils for Cooling--1 to 8 rows deep. Refrigeration Coils--all types and sizes. Special Colls--of various materials furnished on order for special applications. 1236 McQuay, Inc. Air Conditioning Unit Heaters and Coolers Horizontal Unit Heater HORIZONTAL UNIT HEATERS Three basic types available--Standard High cfm, and Textile. 13 Standard models ranging in size from 21,600 to 360,000 Btu; 11 High cfm models 20,300 to 248,000 Btu; 5 Textile models 38,100 to 196,300 Btu. Write for Catalog 322. Down Flow Unit Beater DOWN FLOW UNIT HEATERS Two basic types available--Standard and High cfm. 11 Standard models ranging in size from 39,300 to 500,000 Btu; 11 High cfm models 25,400 to 289,000 Btu. Write for Catalog 760. "RH" AIR CONDITIONER (For Small Commerical Jobs) Deluxe units with attractive appearance. Four basic sizes: 1000, 1500, 2000, and 3000 cfm. Nominal capacities range from 2 to 10 tons. Freon and water cool ing coils-steam and water heating coils. Write for Bulletin 86A. BLOWER TYPE UNIT HEATERS Horizontal, vertical, wall and inverted types. Covers the entire range from 1280 cfm and 26,000 Btu to 32,000 cfm and 2,227,000 Btu. Filters, face and by pass dampers, mixing boxes, humidifiers, and all styles of discharge nozzles are available. Write for Catalog 344. Air Conditioner {Year-Round) Blower Type Unit Healer SEASONMASTER (Central- Station Air Conditioner) Horizontal and Vertical types. Cools, dehumidifies, filters, and circulates air in summer; heats, humidifies, filters, and circulates air in winter. Freon and water cooling coils--steam and water heating coils. Cooling capacities from 1 to 100 tons, cfm from 640 to 21,000 in both sus pended and floor type. Write for Cata log 505. SEASONMAKERS (For Multi-Room Buildings) Room air conditioner, four types: floor, Seaeonmaker {Ceiling Type) hideaway, basic, and ceiling. Cooling and heating medium supplied from cen tral plant. Cools, dehumidifies, and filters in summer; heats and filters in winter. Three basic sizes: 200, 400, and 600 cfm (up to 25 per cent of cfm may be fresh air). The Seasonmaker's com pactness, attractiveness, quiet opera tion, and ease of installation make it ideal for hotels, apartment buildings, hospitals, motels, etc. Write for Bulletin 700. Seawmmaster Air Conditioner CYear-Round) s"onmaier (Floor Type) ICY-FLO ACCUMULATORS The practical "Storage-Battery" for re frigeration effect is now available for handling heavy loads of short duration. Ideal for churches, lodges, mortuaries, noon cafeterias, and many industrial applications. Write for Bulletin 108. 1237 Accumulator Air Conditioning _ Unit Heaters and Coolers | McCord Corporation AIR CONDITIONING AND REFRIGERATION DIVISION Detroit II, Michigan If i' FACTORIES: DETROIT, MICH., WASHINGTON, IND., WINDSOR, CANADA v MANUFACTURERS OF UNIT HEATERS, CONDENSERS FOR DOMESTIC AND COMMERCIAL REFRIGERATORS S MCCORD HORIZONTAL TYPE UNIT HEATERS r 16 models for industrial, commercial general office, and store use--a type v size and design for every application. Features: modern design, high capacity. / Air Conditioning Unit Heaters and Coolers D. J. Murray Manufacturing Co. yr T. H. REO. U. t. FAT. OFF. Wausau, Wisconsin . Offices in Principal Cities MANUFACTURERS OF GRID UNIT HEATERS AND GRID BLAST COILS Designed and tested to operate with steam or hot water systems--for steam pres-sures from 2 lbs to 250 lbs. GRID Unit Heaters are "Put up to stay up" without repairs or other maintenance. . .service records from all types of industry prove it. 12 models for overhead installation--up near the ceilings, in bays, or at low levels in offices and stores. McCord unit heaters incorporate every unit heater advancement that McCord en gineers and the experience of thousands of users could suggest. The spiral fin tube surface as used in McCord horizontal and vertical types provides a type of heat trans fer surface of maximum efficiency. Constructed entirely of copper, the fins are bonded by solder. The solder protects the fins from external corrosion, prolonging the life of the heating element. Individual tubes prevent stresses due to unequal expansion. Tube headers are rounded for strength. Improved fan blades deliver large quantities of air with minimum noise or vibration. The design of the die-formed air inlet is an improvement that increases air quantity and decreases noise and horsepower. The motor support is nonair-restricting. Standard base type motors are used, making replacement easy if it should ever be necessary. CONDENSERS FOR DOMESTIC AND COMMERCIAL REFRIGERATORS McCord refrigeration condensers are fab ricated by the most modern and econom ical methods, resulting in a high quality product at low cost. The McCord coin struction permits use of continuous tubing without joints, eliminating possi bility of leaks. Fins are permanently copper-brazed to the tube. Complete range of sizes. 1238 One piece construction "fin" heating sections of high test cast iron--no sol dered, brazed, welded or expanded con nections. Patented. Overall dimension* for installation of Cast Iron GRID Unit Heater Cl (CAST IRON) SERIES GRID UNIT HEATER DATA Mode! No. A Dimensions BCD E Cl-1000 Hi 141 13* 181 121 121 9} m 1513 >M 16 23 17* 1M m 21 28 CI-4C5 221 221 271 20ft HI 20* m 261 13 21ft 28 261 35J 261 36J 271 261 13 261 36 2/1 2if 13 31 40 32| 31 13 31 40 321 31 13 31 40 Motor Vol. Fan CFM HP RPM Capacities 5 PSI Steam 60F Air Btu/ Hr Final Temp. F 1/20 1/12 1/8 1/8 1/6 1/6 1/2 1/4 1/2 1/2 H 1550 1700 1750 1750 1150 1150 1150 1150 1160 850 1150 572 20,080 798 45,450 1500 76,500 1700 101,500 2600 143,000 2875 173,640 4350 224,000 3300 206,000 4650 275,000 6300 332,000 8000 330,000 106 112 107 114 110 115 107 117 114 108 103 Pipe Size Supply Return nn au U li nu 2 li 2u 2 li 2u 2 li 21 n 21 h Sup port Rod Dia. Approx. Snip. Weight Lbs. H 150 H 210 H 280 h 390 H 490 a 520 700 n 660 if 900 H 1020 X 1070 NO ELECTROLYSIS TO CAUSE CORROSION kw maintenance expense. ^fore air changes per hour. Positive "directed" heat. No taaks--no breakdowns. . Lower outlet temperature. Larger air volume. . No soldered, brazed or expanded joints. Open design that keeps units clean. Send for complete Catalog information Send for Information on Blast coils and radiation. 1239 Air Conditioning 2?cSSP f - -- ^ Modine Manufacturing Company Heating and Air Conditioning Division General Offices: 1515 Dekoven Ave., Racine, Wis. Factories at Racine, Wis., LaPorte, Ind., Paducah, Ky, and Whittier, Calif. Sales Representatives m all Principal Cities .. MODINE UNIT HEATERS FOR HOT WATER AND STEAM ^ Horizontal Delivery--Modine gives you 23 Models to choose from. Built for general industrial and commercial appli cations. Vertical Delivery--26 Models designed ^ for high overhead installation or at low levels. A fully coordinated line of Modine Unit Heaters offers greatly expanded oppor tunities for correct unit heater applica tion. Used individually or in combina tion, they meet the exacting engineering demands of any space heating applica tion. Rugged Condenser--Tubes and headers are cylindrical and brazed at the joints for greater pressure-resisting strength. Individual expansion bends absorb dif ferential stresses. One-Piece Construction--Tubes, header, inlet and outlet connections are brazed into a rugged, pressure-resisting unit. Safety Fan Guard--On all Horizontal models, a built-in fan guard offers con stant protection from exposed fan. Bonderized Casings--All .Unit Heater casings are Bonderized to prevent rust and bond paint to steel. Efficient Motors--Nationally known makes of continuous-duty, totally en closed fan type. Rubber mounted to prevent vibration noise. ' Easy Installation--Direct-from-pipe line suspension for low cost, fast installation of all Horizontal types. Accurately rated in strict accordance with the Standard Test Code for Unit Heaters. NEW MODINE GAS-FIRED UNIT HEATERS New Modine Gas-Fired Unit Heaters mfive sizes . . . from 217 to 733 EDR - * feature lightweight, smaller size, greater durability and faster response to auto matic controls. Heat exchangers and burners are cor rosion-resistant stainless steel. Tubes are individually fired for most effective heat transfer. Elongated burner ports having approximately four times the free area of conventional drilled ports, dis courage clogging and minimize cleaningAll models are A.G.A. approved for natural, manufactured, mixed, LP and ----- LP-air gases. Modine Manujacturing Company Air Conditioning StSSST MODINE CONVECTOR RADIATION Available in Standard enclosure styles and in heavy-duty Institutional models. Enclosures are bonderized. ^Accurate ratings are determined in conformance with Commercial Standard CS-I40-47 as developed by the National Bureau of Standards and approved by the Convector Rating Committee. TYPE IF--Institutional style for recess ing or free standing installation. Op tional special tamper-proof fronts and dampers. Institutional models also available in the wall types IW and IS. TypeF TYPE F Shown with attractively Jouvred lower grille and fingertip control damper' both optional. Ideal for either complete or partial recessing in a wall or for flush installation against a wall. TYPE S--Wall type with air outlet grille incorporated in sloping top. Also avail able in heavy gage metal for institutional use. Type W, another wail hung en closure resembling the Type F, can also be furnished in heavy-duty models. TYPE F-12---Designed for free-standing or recessed installation beneath a picture window, convector has an over-all height of only 12 in. Damper and lower grille are optional. MODINE CABINET UNITS Type P IS MODINE HEATING COILS The extensive line of Modine Heating ,,ou! is engineered to meet the diversified qmrements of modern air-handling systems. In addition to more than 1200 catalogued heating coils for use with mf3111 a,1( water, Modine produces in built coils for installation ntv"r' hng equipment produced by r brms. Types include standard an,) reeze beating and booster coils, and hot water heating coils. Completely redesigned, the Modine Cabinet Unit line provides economical heating, cooling and ventilating where the expense of air conditioners or unit ventilators is not warranted. A single unit can provide quick, positive, quiet distribution of heated or cooled air, with or without ducts. Addition of inexpen sive accessories permits introduction, filtering, heating and distribution of fresh outside air for ventilation. Five different models provide (1) heat ing with steam or hot water and (2) cool ing with chilled water in addition to heating. Various combinations with or without optional equipment permit free standing, recessed and concealed instal lations--floor, wall or ceiling mounting. 1241 Air Conditioning Unit Heaters and Coolers herrirr reisor American Air Filter Company, Inc. Office -- Louisville, Ky. Factories -- Louisville, Ky., and Moline, 111. Branch Offices and Product Application Engineers in Principal Cities < HORIZONTAL SHAFT PROPELLER-FAN TYPE UNIT HEATERS. For ceiling or wall mounting. Use with steam or hot water. Copper heating element with patented stay tube prolongs unit life. Many models and sizes. Bulletin 700. Horizontal Shaft Heater 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 avail able in range of capacities with high or low velocity discharge. Bulletin 700. Gas Fired Heater < GAS FIRED UNIT HEATER. Operates on all types of gas. Compact in design-- easy to install--readily moved. Avail able in 7 sizes with heat output ranging from 20,000 to 160,000 Btu's per hour. Bulletin 715. Vertical Shaft Healer DE LUXE UNIT HEATER. Compact, quiet, economical and^. DeLuxe Unit Heater attractively styled. Ideal for offices, showrooms, corridors, stores, etc. May be placed on floor, wall or suspended from ceiling. 18 models and sizesBulletin 725. CENTRIFUGAL FAN UNIT HEATERS. Use has supplied, solution to many heating and ventilating problems. Wide variety of models, sizes and speeds assure right unit for every commercial and industrial building need. Bulletin 750. ^ Centrifugal Fan Unit Heaters Unit Ventilator DRAFT/STOP UNIT VENTILATORS. A Unit Ventilation System that traps cold drafts before they reach classroom occupants--automatically heats, ventilates and cools. System is quiet and economical--requires little maintenance. Bulle tin 600. Herman Nelson Unit Heaters and Unit Ventilators are tested and rated in accord ance with the Standard Test Code adopted jointly by the Industrial Unit Healer Association and ASHVE. 1242 Air Conditioning HERmnn nELson American Air Filter Company, Inc. Louisville, Ky. Moline, M. Unit Heaters 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. ` Propeller Fans 4 UNIT BLOWERS. Direct or belt drive with forwardly curved or backwardly inclined wheels. Wheel diameters from 4/^-in. to 30-in. and capacities from 160 to 18,303 cfm. Bulletin 825. Unit Blowers 4 VENTILATING UNIT. Features one, two or three fans on a common shaft and housed in compact cabinet for straight line air movement. Useful for booster work in ducts or untempered air supply or exhaust. Bulletin 765. Ventilating Unit HEATING AND VENTILATING UNIT.*. Features sectionalized construction, low outlet velocities, slow fan speeds, wide selection of heating coils. Available with humidifier. Ideal for institutional or commercial use. Bulletin 775. ^ CENTRIFUGAL FANS. Designed for*, systems requiring a Class I or II cen-. trifugal fan. Slow speed or non-over loading type. Wheel diameters from to 73-in., single or double width. Direct or belt drive. Any rotation or discharge. Bulletin 850. Herman Nelson Propeller and Centrifugal Fans are tested and rated in accordance with the Standard Test Code adopted jointly by the National Association of Fan Manufacturers and ASHVE. 1243 Air Conditioning Unit Heaters and Coolers JOHN J. NESBITT, INC. Philadelphia 36, Pa. mouiuavvuiU!) av*f NESBITT SCHOOLHOUSE HEATING AND VENTILATING EQUIPMENT AND AUXILIARY STORAGE CABINETS Ensemble of the Nesbitt Syncretizer and metal shelving. THE NESBITT PACKAGE The modern classroom ensemble of Nesbitt Storage Cabinets, Auxiliary Con vectors where, desired, and the Nesbitt Syncretizer--the heating and ventilating unit for schoolrooms, offices, etc., that sets a new standard of comfort. The Syncretizer is a fully-automatic unit adaptable to three cycles of control--to circulate all outdoor air, or varying per centages with and without a fixed mini mum. Doubly controlled by a room thermostat and air-stream thermostat or Comfort Control, an exclusive Nesbitt feature, designed to maintain optimum thermal conditions. The Syncretizer provides quick, economic heat without overheating; draft-free ventilation and cooling when needed; room.-by-room bal ance. Sturdily designed for modern interiors, quiet-operating. Models to deliver from 750 to 1560 cfm anemometer rating. Publication 261, Section A. Watt-hung easing WIND-O-LINE RADIATION For integration with the Syncretizer under large glass areas with cold expo sures. Consists of fin and tube radiation in a grilled wall-hung casing, or recessed in components of the Nesbitt Package. Controlled in cycle with the Syncretizer to meet the heat demands of low tem perature surfaces. Capacities 450, 550 and 700Btu/lineal ft. Pub. 261, Section W. SERIES T THERMOVENTS New higher capacity heating and ven Horizontal mounted Series T Thermoveni tilating units for large auditoriums, gyms, shop rooms, cafeterias and similar gathering places. Available for both low-pressure and high-pressure, rela tively high - resistance applications. Special acoustically treated discharge section assures quiet operation. Avail able in capacities from 1250 to 15,000 cfm. Publication 270. SILL-LINE RADIATION WITH STORAGE CABINETS For the many installations which require practical storage space combined with a need for heating facilities, Nesbitt Open and Closed Storage Cabinets integrated with Sill-line Radiation are now offered. This low-cost combination of high-capacity perimeter heating with storage shelving is de signed for modern schools and offices where automatic ventila tion is not required. Cabinets are available in 28 in. and 32 in. heights, 2 ft, 3 ft and 4 ft lengths to form continuous ensembles. Special Piping Compartments and Fill-in Sections conceal con trol valves, piping, etc. Steam capacities from 1315 to 2265 Btu per hr per lineal ft, true condensation. Publ. 261, Section S- 1244 Air Conditioning * Sd<Si25rB JOHN J. NESBITT, INC. Philadelphia 36, Pa. NESBITT SILL-LINE RADIATION All the advantages of high-capacity perimeter strip heating in an enclosure design that harmonizes with modern interiors. For use in hospitals, schools, apartments, showrooms, etc. Made in three cabinet sizes, five lengths from 31^ to 8 feet; two fin sizes for single or double tiering. Capacities from 1250 to 2290 Btu per hr per ft. Publication 276. NESBITT CONVECTORS Designed for two-pipe steam, forced or gravity hot water heating of offices, residences, apartments. Available in 23 stock sizes: heights 20 and 24 in.--lengths 16 in. to 88 in.-- capacities 13 to 88.5 sq ft EDR. Universal cabinets for free standing or semi-recessed installation. Pub. 262. NESBITT SURFACE SERIES W. Continuous or cleanable tube water surface for air-cooling, dehumidifying or heating. Copper tubes, aluminum fins. Wide range of sizes in three types: Type WD with exclusive freeze-proof drainability feature and sur face pitched in the casing. Pub. 246. Type WB sections for booster-heating or air-cooling relatively small air volumes; without drainability feature. Type WC employs standard Series W cores pitched in the casing; cast iron headers and re movable cover plates. Single or double serpentine circuits. Pub. 256. SERIES H. General blast coil surface for heating,- ventilating, air-condition ing and drying in both high and low pressure systems. Copper tubes, alu minum fins. Seven types, full range of sizes. Pub. 248. SERIES D. Steam-distributing tube surface. Freeze-proof. Ideal for pre heating outdoor air; uniform discharge temperatures; precise controllability with modulating valves. Type DS: Sin gle supply header with single steamdistributing tubes for normal heating and ventilating applications, or DUAL tubes in finned lengths up to six feet. Type DD: Two supply headers; DUAL steam-distributing tubes. Finned lengths from 78 in. to ten feet. Pub. 247. NESBITT GAS-FIRED UNIT HEATERS Modern, attractive direct-fired unit heaters in seven basic models ranging in capacity from 25,000 to 200,000 Btu heat input. Made of die-formed furniture steel finished in heatresistant, baked-on enamel. Low-speed motor equipped with thermal overload protection. Quiet-operating fans; dieformed adjustable louvers. Equipped with automatic con trols and safety pilot. Units are A.G.A. approved and listed by Underwriter's Laboratories. Publication 280. NESBITT BASEBOARD RADIATION A new approach in baseboard design. PlJJbines an enclosure of unusual beauty ith a heating capacity ample to achieve true perimeter heating (4.1 sq ft EDR ana inea* ft). 1-B=R approved steam a hot water ratings. Copper tube, uminum fin element. Furniture steel cabinet in 4, 6, 8 ft lengths. Pub. 272. 1245 Air Conditioning Unit Heaters and Coolers The TRRI1E Company La Crosse, Wisconsin In Canada- Trane Company of Canada, Ltd., Toronto, Ontario--Offices in 14 Canadian Cities COMPLETE LINE HEATING AND CONDITIONING 89 Trane Sales Offices in U. S. , Albany, N. Y. Allentown, Pa. Amarillo, Texas Appleton, Wis. Asheville, N. C. Atlanta, Ga. Aurora, III. Baltimore, Mo. Baypoet, L.I., N. Y. Billings, Mont. Birmingham, Ala. Boston, Mass. . Buffalo, N. Y. Canton, Ohio Charleston, W. Va. Charlotte, N. C. Chattanooga, Tenn. Chicago, III. Cincinnati, Ohio Clarksburg, W. Va. Cleveland, Ohio Columbia, S. C. Columbus, Ohio Dallas, Texas Davenport, Iowa Dayton, Ohio Denver, Colo. Des Moines, Iowa Detroit, Mich. Duluth, Minn. Erie, Pa. Fargo, N. D. Flint, Mich. Gainesville, Fla. Grand Rapids, Mich. Greensboro, N. C. Greenville, S. C. Harrisburg, Pa. Houston, Texas Indianapolis, Ind. Jackson, Miss. Johnson City, Tenn. Kansas City, Mo. Knoxville, Tenn. La Crosse, Wis. . Lansing, Mich. Little Rock, Ark. Los Angeles, Calif. Louisville, Ky. Memphis, Tenn. Miami, Fla. Milwaukee, Wis. Nashville, Tenn. Newark, N. J. New Orleans, La. New York, N. Y. N. Tarrytown, N. Y. Oklahoma City, Okla. Omaha, Nzbr. Peoria, III. Philadelphia, Pa. Phoenix, Ariz. Pittsburgh, Pa. Portland, Me. Portland, Ork. Providence, R. I. Raleigh, N. C. Richmond, Va. Roanoke, Va. Rochester, N. Y. St. Louis, Mo. St. Paul, Minn. Saginaw, Mich. Salt Lake City, Utah San Antonio, Texas San Francisco, Calif. Seattle, Wash. Sioux City, Iowa South Bend, Ind. Spokane, Wash. Syracuse, N. Y. Toledo, Ohio Trumbull, Conn. Washington, D. C. West Hartford, Conn. Wichita. Kans. Wilkes-Barre, Pa. . Wilmington, Del. Worcester, Mass. A COMPLETE LINE. The Trane Company fabricates a complete line of heating, cooling, air conditioning, airhandling and heat transfer equipment. Any number of complete heating and air conditioning systems can be designed in which all the major parts are made by Trane. CONVECTORS--Attractive, efficient, easy-to-install units for either steam or hot water heating systems. Wide range of cabinet types in a multitude of sizes. COILS--Extended Surface Coils for most heating or cooling applications; for steam, hot water or booster heating, direct expansion or water cooling. PROJECTION UNIT HEATERS-- Model "P" taps the reservoir of ceiling heat, solves multitude of heating prob lems. Louver Cone diffuser, optional. HORIZONTAL UNIT HEATERS--Com bine Trane broad blade propeller fan and extended surface coil into a heater that is rugged, efficient and handsome. In 24 sizes, 22,000 to 352,000 Btu. Louver Fin diffuser, optional. BLOWER TYPE UNIT HBATERS-- Trane Torridors combine Trane Cen trifugal Fans and Extended Surface Coils for heating and ventilating large spaces and for process applications. GAS UNIT HEATERS--The built-likea-boiler unit that's suitable for most heating applications. Available in six sizes. 50,000 to 230,000. Btu1 capacities. FORCE-FLO HEATERS--De luxe unit heater with centrifugal fan. A power house of heat in a neat appearing cabi net. Capacities: 17,700 to 105,000 Btu. Force-Flo Heater 1246 Wall-Fin Heater The Trane Company Air Conditioning Unit Heaters and Coolers WALL-FIN HEATERS--Finned radia tion, ferrous or nonferrous. Lengths 2 ft to 12 ft, in 6 in. increments. Expanded metal grilles and cabinets available. UNIT VENTILATORS--Kinetic Barrier System with lateral extensions provides constant protection against downdrafts. Matched shelving and convectors, op tional. ROOF VENTILATORS--Complete line of supply and exhaust ventilators and ventilating heaters. 355 to 25,000 cfm. BASEBOARD CONVECTORS--Nonfer rous fin-and-tube heating element. At tractive steel cabinets, in. or 12 in. height. Damper or valve controls op tional. STEAM SPECIALTIES--Complete line for pressures up to 200 lbs, including radiator and temperature control valves, strainers, vents, bucket and float traps. HOT WATER SPECIALTIES--Circula tors, FloValves and Fittings. Combined with Trane Convectors they provide an ideal warm water heating system. MULTI-ROOM AIR CONDITIONING SYSTEMS--Custom-Air for separate control of temperature and moisture; UniTrane for control of temperature and moisture without the use of ducts. SELF-CONTAINED AIR CONDITION ERS--Packaged units for offices, shops or home air conditioning. 3 to 20 tons. CLIMATE CHANGERS--Unit type air conditioners for year-round air condi tioning. Has various coil combinations with or without humidification equip ment. Capacities: 450 to 23,000 cfm. EVAPORATIVE CONDENSERS--For condensing Freon and Methyl Chloride. refrigerants. Use minimum amount of water. Sizes from 3 to 100 tons. Centrifugal Fan COLD GENERATORS--Packaged water-chillers shipped assembled, tested, ready to install. No refrigeration work required. Ten sizes, 10 to 100 hp. EQUIPMENT--Trane CenTraVac is a hermetic centrifugal Scration unit in 8 sizes with capacities from 50 to 400 tons. Trane Reciprocating nipressors and Condensing Units are available from 3 to 100 tons. Class I and II. Non-overloading backwardly inclined or slow t.ipc .ftr?r4VaAP,c^7e<! tyPs. .aU arrangements. Wheels from 12 in. to 108 in. Capaci- - oo6 to 491,000 cfm. Utility and propeller fans with direct or belt drives. MATERIAL--Trane Air Conditioning Manual ($5.00), an unbiased en,loD?0k tor engineering profession. Trane Refrigeration Manual ($1.50), a refer- ior servicing and installing all types of refrigeration systems. OTUnr. mv. ______ ______ ____ __ " Tnha li * t-t ** transportation Air Conditioning Equipment; 7. Shell-and- Cnnri;*-eat Exchangers; 8. Evaporative Coolers; 9. Air Washers; 10. Multi-Zone Air tioners; 11. Mechanical Refrigeration equipment for railroads. 1247 Air Conditioning Unit Heaters and Coolers Refrigeration Economics Co., Inc. 1231 Tuscarawas St. E., Canton 2, Ohio . RECOY PRODUCTS FREEZE PROOF WATER COOLERS PATENTED BULLETIN 0-52 BEFRicERtrvr suction CYlinOKKAL OUTER IHtU DISTRIBUTED THERMAL VALVE WATER RETURN WATER OUT # . PATENT JJ3- g5n)69 VERTICAL SECTION ./METAL FirtSTOOlpECT WATER ROTW BACK AHP FOrTH $ In '-fr % 'S'- Air Conditioning Unit Heaters Office and Factory linden, n. j. L. J. Wing Mfg. Co. 59 Vreeland Mills Road, Linden, N. J. Canadian Factory: MONTREAL Branch Offices in European Representative for Heaters: Principal Cities Wanson, Haren-Nord, Brussels, Belgium WING REVOLVING UNIT HEATERS The moving streams of heated air (or cooling breezes in summer) sweep slowly around through 360 deg covering sue- cessively every^ direction. The air velocity is sufficient to carry to walls and remote corners and around obstructions. FREEZE PROOF--Freezing does not damage as water is outside the cooling coil and freezing only distorts the light sheet metal coil casing. No damage results unless the freezing extends to outer shell and even then water does not get into the refrigerant NO OIL LOGGING--Oil returns with refrigerant. . MINIMUM FREON CHARGE--5 to 8 lbs per ton. CLEANABLE COOLER--Cooling coils are removable for cleaning or repair. CAPACITIES--Supplied in sizes from 2 to 100 tons, as coolers only with thermal' valves, coolers with insulation and steel lagging, or complete assembly including condensing unit and all controls. - High ceiling installation in airline hangar. Revolting Medium ceiling installation in manufacturing plant, outlet is Design No. 8. Revolving outlet is Design No. 5. An outstanding and exclusive feature of WING Revolving Unit Heaters is the revolving air distributor having one or more outlets. As the distributor slowly turns, heated air is delivered from each outlet obliquely downward, in every changing direction, to the working floor. The warm air spreads across the floor and around obstacles creating a warm, pleasant atmosphere. In warm weather with the heat turned off, the WING Units furnish zephyrs of cooling air appre ciated by workers. Write for Bulletin HR-6. C. F. COILS--Continuous fin coils for air conditioning, heating, and cooling. . AIR CONDITIONING--Air conditioning units of ceiling or floor type in all capac ities, for cooling, heating, or both. 1248 1 2 34 Left to right: WING Stationary Discharge Unit Heater, (2) WING Utility (Hori zontal Discharge) Unit Heater, (3) WING Electric (Horizontal Discharge) Unit Heater, (4) WING Gas-fired Unit Heater. ' 1249 Site. Air Conditioning Ventilation Office and Factory LINDEN, N. J. L. J. Wing Mfg. Co. 59 Vreeland Mills Road, Linden, N. J. Canadian Factory: MONTREAL - Branch Offices in European Representative for Heaters: Principal Cities Wanson, Haren-Nord, Brussels, Belgium WING FRESH AIR SUPPLY HEATERS {Above) Freeh Air Supply Beater with,motor and fan above roof level. (Right) Fresh Air Supply Heater in plant of finishing company, pro viding warmed make-up air from outside, . . _____|_____cou ia i 1 COlO Alfl ) 4 t 1 i{l i i'MIXCO WARM1 AIR 1 ( i V V LI * li II II u os-- O-a4 o-X4 *H mot Ata oclivcrco (Above) Section of heating element in Wing Fresh Air Supply Heater, showing action of thermostatically controlled dampers in adjusting temperature of incoming air to requirements of room or building. When ventilating and fume exhaust systems do not provide adequate fresh air supply your plant may be literally "starved for air." WING Fresh Air Supply Heaters provide an adequate supply of properly warmed, evenly distributed fresh air without chilling drafts. They cannot freeze, as the steam is on all the time. The diagrams above show how the temperature is regulated. Write for Bulletin HS-3. Air Conditioning T>mtt inducers Office and Factory UNDEN, N. J. L. J. Wing Mfg. Co. 59 Vreeland Mills Road, Linden, N. J. Canadian Factory: MONTREAL Branch Offices in European Representative for Heaters: Principal Cities Wasson, Haren-Nord, Brussels, Belgium WING DRAFT INDUCERS WING DRAFT INDUCERS for heating boilers assure positive draft regardless of weather conditions or of inadequate chimney or breeching construction. They eliminate the need for high stacks or chimneys. They insure boiler operations at maximum capacity. They may be installed in the flue, in the breeching or at the top of the chimney. New design (shown at left) has interchangeable in lets, automatic belt tension, pre-sealed lubricated bearings. Fan and bearing as sembly may be withdrawn from housing for inspection or servicing. {Abate) H ing Draft Inducer in stalled in heating plant of na tionally known bottling concern. {At right) Note absence of < ll chimneys in plant equipped with B'tnj,. Draft Inducers. The new Wing Draft Inducer requires no aignment in the field as shaft and bearings are rigidly mounted at the acton. Wing Draft Inducers are available in a wide range of capacities for handling loads up to 100,000 lbs of steam per hour. Send for Bulletin 1-62. Left to right: WING Variable Temperature Heater Section for air heating, drying and process work. (2) WING Vaneaxial Duct Fan has motor in casing, dust-proof, pre-sealed bearings. (3) WING Elbow Type Duct Fan. Motor and drive outside airstream. (4) WING Straight Line Duct Fan. Easily installed in run of duct. 1250 12 3 4 Left to right: WING Power Plant Draft .Inducer. (2) WING Motor Driven orced Draft Blower, manual or automatic capacity regulation. (3) WING Turbine oven Blower, capacities to 50,000 cfm, statics to 15 in. (4) WING Steam Turbine 'or driving fans, pumps, etc. ' 1251 Air-Conditioning Unit Heaters and Coolers HhNlll1 Radiator Co. Dept. 544, Racine, Wis. Sales & Engineering Representatives in ail Principal Cities- Heating, Cooling, Air Conditioning Products for Home and Industry, Heat Transfer Products for Automotive, Agricultural, Industrial, Gas and Diesel Engine Applications CONVECTORS & UNIT HEATERS ^Convectors are available from stock in six standard cabinet styles; also Insti tutional and bathroom models; for steam or hot water systems. "Vertlflow" Unit Heaters are built in^ seven models; capacities from 52,600 to" 552,000 Btu per hr; adjustable louvers, nozzles, diffusers, Anemostats. Type "SH" Unit Heaters are built in 14 models; capacities from 19,000 to ^325,000 Btu per hr; for steam and hot water systems. Cabinet Type Unit Heaters are avail able in number of arrangements, wall hung, horizontally suspended, etc.; fromP' 26,200 to 115,000 Btu per hr. Type "BH" Blower Unit Heaters for floor, wall or ceiling mounting, designed 4to heat extra large industrial buildings, garages, etc. Gas-Fired Unit Heaters are available in eight sizes ranging in capacities from 50,(MO to 230,000 Btu/hr input. Have welded corrosion-resistant aluminized^ steel combustion chamber and. heat ex- changer; other important design features. AIR CONDITIONING UNITS ^ Young "YAC" Air Conditioning Units provide year around service for cooling, heating, filtering, circulating, humidi fying and dehumidifying in any com bination. Units are available in eight sizes; capacities from 400 to 15,748 cfm; vertical (right) or horizontal types; for air conditioning stores, hotels, theaters, etc., and specialized industrial applica tions. Heating coils are furnished for either steam or hot water; cooling coils for water or direct expansion operation. HEATING & COOLING COILS Young manufactures a complete line of heating and cooling coils for central heating or cooling systems, etc. Type "W" Water Coils--Serpentine tube construction with casing; for either cold water cooling or hot water heating sys- terns. Type "K" Water Coils--Cleanable tube type; used in either cold water cooling Type "HD" for heavy duty applica tions. Type "SD" Steam Distributing Tube Heating Coils--Complete with casing; for heating, ventilating, and air condi tioning systems. . Type "E" Evaporator Coils--For direct expansion cooling systems using Freon or Methyl Chloride. , Special Purpose Coils--Unencased ana or hot water heating systems. built in many sizes for use in factory- Type "S" Standard Heating Coils-- built air conditioning, heating, drying Complete with casing; also available in and special processing units. 1252 Air Conditioning . "&SS1" 4'5 .Crouch Sti FOR HOMS LtCTR0M0D INDUSTRY FARM CUtSiecOic HEATERS J BILT-IN-WALL Heaters for Homes and Offices Using Electromode's Down-Flo princi ple, these heaters fan-circulate warm air at floor level for greater comfort and im proved heating efficiency. Quick and easy to install. No duct work required. Famous cast-aluminum heating element elimi nates all danger of fire, shock or burn. Ca pacities from 1500 to 4000 watts--with manual, wall thermostat or built-in ther mostat control. All have thermal safety switches. Silver gray enamel finish. j BILT-IN-WALL BATHROOM Heater j Designed to build into the wall, this 110 volt, 1320 watt heater S is designed for small rooms such as baths, bedrooms, kitchens, j etc. Employs the famous cast-aluminum heating element that ; is completely safe. Available with or without built-in ther| mostat. Thermal cut-off prevents overheating. Two-way switch : permits use of fan without heat. Available in white baked-on * enamel or chrome. UNIT HEATERS for Auxiliary Warmth These fan-circulating units are used as auxiliaries to a main heating system or, where electric rates permit, as main heating sources. Require no plumbing or duct work--only circuit wir ing. Employ the completely safe cast-aluminum heating ele ment that has no exposed hot or glowing wires, gives high thermal conductivity and resists corrosion. Safety switch pre vents overheating. Thermostat control available on all models. Suspension Type (left) for wall or ceiling mounting in factories, stores, offices. 10,000 to 45,000 watts. Combination Portable and Suspension Type plugs in where needed or mount permanently. 1500 to 7500 watts. Automatic thermostat control available on 1500 to 5000 watt models. Explosion-Proof Heaters (left) for areas charged with inflam mable vapors. Convection type. Entire electrical input pro vides useful heat. Three models range from 2000 to 6000 watts. Listed by Underwriters' Laboratories for Class 1-Group D Hazardous Industries. Engineering help is at your disposal. For more information, see your supplier or write Dept. HVG-14, Electromode Cor poration. - Electromodes are approved by Underwriters' Laboratories and are fully guaranteed. 1253 Air Conditioning Unit Heaters,' Electric AUTOMATIC HEAT Wesix Electric Heater Co. 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 available in standard lengths for simple, inexpensive installation without special tools or metal cutting. Heating lengths: 32 in. and 48 in., 157 watts (536 Btu) per lineal foot. Control Section (thermostat and switch) 6 in. long. 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 FUR NACE sizes range from one to eight kilo watts for use in domestic and commercial installations. Available in radiant-con vection (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 complete with sensitive inte gral overtemperature control. . LOAD REGULATORS control electric heating capacity 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 verti cal 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. Ap proved by UL. QUIET AUTOMATIC SWITCH, a motor operated contactor for resistance loads to 24 kw, 1^ or 40 kw 3^, 240 volts and 33 kw 1$ 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 UL. COMMERCIAL UNIT HEATERS--AXIAL FLOW sizes from 3 to 40 kw for ceiling or pedestal mount. Feature Wesix longi tudinal fin, "dust free" inclosed heating elements. Approved by UL. HEAVY DUTY WALL THERMOSTAT AND SWITCH for control of electric heating apparatus directly up to 30 ampi this unit includes a lockout switch double-pole in the "off position. Thermostat action is bi-metallic, sensitive to 2<^FFits standard wall box mounted horizontally. Approved by UL. 1254 Air Conditioning Unit Heaters Edwin L. Wiegand Company 7672 Thomas Boulevard Pittsburgh 8, Pa. Representatives in all Principal Cities. Over 15,000 types, sizes and ratings of Chromalox electric heating units are made to efficiently and economically do your heating jobs. Chromalox heaters give you clean, dependable electric heat, when and where heat is needed. Uniform and ac curate temperatures are easily achieved by automatic or manual control.. CHROMALOX CIRCULATION HEATER Chromalox Circulation Heaters are used for heating water for convection or forced water heating systems; for wash rooms; shower rooms, laundries, dish washers; process kettles and tanks; heating water; drying steam; preheating fuel oil; heating heat transfer mediums; heating nitrogen and other gases. Tem peratures to 750F. CHROMALOX BLOWER TYPE UNIT HEATERS These heaters are easily installed wher ever temporary or permanent comfort heatingjis needed. Motor-driven fans assureSadequate supply of heated air. Available with manual or automatic controls in 1.5 to 4.0 kw capacities. CHROMALOX FINSTRIP HEATERS Finstrip heaters are used in air ducts wit h. forced air circulation, process work requiring heated air blasts, ovens, dryers, etc. Temperatures up to 750F easily obtained and accurately main tained by thermostatic controls. Air blast heater for heating larger rooms, factories, etc. Air ducts can be used to carry warm air to any desired locations. Complete with CAB heat units mounted within cabinet, centrifugal fans and 3phase motor. Ratings from 51,180 to 136,480 Btu's per hr. CHROMALOX CAB & CABB FORCED AIR DUCT HEATERS Hm-ioT'" s.<iuar? or rectangular air 3 2,r heating air over forced circula- ... il ^or. room heating and process ;n freclu*rlng heated air blasts. Ratngs from 6 kw to 100 kw. CHROMALOX RADIANT HEATERS Far-infrared generator for comfort heat ing, drying, curing, etc. nd for. Catalog D-52 for Comfort Heating; Catalog 50 for Industrial Heating. 1255 Air-Conditioning and Heating Piping copper and Brass * The American Brass Company General Offices: Waterbury 20, Conn. District Offices in Principal Cities AnacSndA from nyne to consumer IN CANADA: Anaconda American Brass Limited, New Toronto, Ontario PRODUCTS--Anaconda Phosphorized Copper Tubes and Fittings; Anaconda "85" Red Brass Pipe; Everdur Metal for storage heaters, storage tanks, ducts and air conditioning equipment ANACONDA COPPER TUBES AND FITTINGS For Heating, Plumbing and Air Conditioning Anaconda Types K and L Phosphorized Copper Water Tubes, assembled with solder type Fittings, offer an unusual combination of advantages for hot water and low pressure steam heating systems, including radiant panels. These advan tages may be summarized briefly as fol lows : stalled in restricted space 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 Specification . B88. Type K, the heavier, is recom mended for heating lines and general piping. . ` Anaconda Copper Water Tubes, in standard sizes are furnished soft in 60 and 100-ft coils; also hard and soft in 20 ft straight lengths. CUSTOM-MADE CAPILLARY TUBES Low Friction Loss--Because the inside surfaces of copper tubes are inherently smoother than those of pipe and tubes made of ferrous materials and also be cause they do not become roughened by the formation of rust, these .tubes offer a lower resistance to flow. In addition, the long-radius turns of elbows and the smooth inside surface of wrought copper fittings further reduce friction losses. These factors naturally increase the efficiency of the system, particularly when it includes a forced-pressure circulator. Anaconda Custom-Made Capillary Tubes, for restriction purposes, are made to specific mutually-agreed-upon airflow limits. These limits alone are the base for production. Initial shipments contain Master Ref erence Sample Tubes with labels giving maximum and minimum flow capacities agreed .upon. Duplicate Master Samples are kept in the mill files. Every subse quent shipment of tubes will be made to the limits of the Master Samples. REFRIGERATION TUBING Ease of Installation--In many places the flexibility of copper tubes simplifies connections that ordinarily would be awkward and expensive to make with rigid pipe and threaded fittings. Solder fittings are compact. They can be in Anaconda Dehydrated Copper Refrig eration Tubes are manufactured in accord ance with the ASTM Specification for this product in all standard sizes up to and including % in. O.D., in 50-foot coilsThe tubes are sealed immediately after annealing and dehydrating. 1256 Air Conditioning and Heating Piping * copper and Brass The American Brass Company VIBRATION ELIMINATORS variety of forms and shapes. Everdur American Vibration Eliminators--Com pressor vibration and noise are muffled in a line equipped with an American Vibration Eliminator. The corrugated bronze tubing is seamless. Copper ferrules alloys are available for oxyacetylene, carbon-arc and inert-gas arc welding. Everdur Tanks--Everdur copper-sili con alloy is an ideal material for durable, non-rusting water tanks of every descrip tion--from domestic range . boilers to and tube ends are braze welded. Each unit is pressure-tested under water, is spot lessly clean and dry, with ends firmly large storage heaters for hotels, laun dries, hospitals, textile plants, schools or breweries. sealed. Everdur is made in all commercial shapes including annealed tank plates ANACONDA "85" RED BRASS PIPE which have physical properties as given in ASTM Specification B96. Anaconda "85" Red Brass Pipe, in standard pipe sizes, is considered, the highest quality corrosion-resistant pipe commercially obtainable at a moderate price and is recommended for steam re turn lines. Minimum specification requirements for hot-rolled-and-annealed tank plates . are: Tensile Strength, 50,000 psi.; Yield Strength (at 0.5 per cent elongation under load) 18,000 psi.; Elongation, 40 per cent in 2 inches. Anaconda "85" Red Brass Pipe con tains 85 per cent copper and conforms to Government specifications for Grade "A" water pipe. The mark "Anaconda 85" is stamped in the metal at one-foot intervals throughout each length. Welds made with annealed Everdur tank plates meet the requirements for construction in the A.S.M.B. Code for Unfired Pressure Vessels. For additional data and names of fabri cators address our nearest District Office. EVERDUR* Everdur Metal is the original coppersfficon alloy group. It is manufactured by The American Brass Company in five standard compositions and in practically all commercial forms. --~~~ --xgjix-tjciGLigLu engineering anoy: are resistant to a wide range of corroding agents. Because of a versatile combina won of useful properties, Everdur has Decome standard as a material for equip indu t*n IUan^r engineering anc In addition to their non-rusting prop erties and high strength, Everdur alloys possess many qualities not. usually und in metals of this character. They e unusually resistant to general atmos nc- con(brions and other normally pvf*r?i81Vf Everdur, alloys have t ` -el.. machining and working charac- sties and can be fabricated into a EVERDUR FOR AIR-CONDITIONIKG EQUIPMENT Because of its strength and welding properties, Everdur may be substituted for steel and fabricated by substantially the same methods and with much the same equipment as steel. Everdur metal has been used with marked success for fans and blowers, ducts, humidifiers, cast and wrought parts of other equipment items subject to corrosive influences. EVERDUR LITERATURE Descriptive literature containing much pertinent tabular data will be sent on request. * "Everdur" is a trademark of The American Brass Company registered at the U. S. Patent Office.' RESTRICTOR TUBE FORMED TUBE PARTS * HARD COPPER TUBE CUT FttNGTH * C0PPER WATER TUBE IN COILS AND STRAIGHT LENGTHS Ft PvrTINGS FOR TYPES K AND L TUBES VIBRATION ELIMINATORS * rnonLE REFRIGERATION TUBING CONDUIT DIE PRESSED FORGINGS '-UPPER, BRASS, BRONZE IN SHEETS, WIRE. RODS, TUBES AND SPECIAL SHAPES 1257 Air Conditioning and Heating Piping Flexible Tubms Ip --- -m M Flexonics Corporation t Chicago Metal Hose-Division | - Maywood, Illinois }?. Atlanta Houston District Offices . Boston Cincinnati Cleveland Detroit Ft. Worth Los Angeles New Yore Philadelphia St. Louis San Francisco Distributing Outlets in Principal Cities In Canada: Flexonics Corporation of Canada, Ltd., Brampton, Ontario FLEXON Super Service Vibra-Sorbers FLEXON Vibra-Sorbers control vibra tion and reduce noise in refrigeration and air conditioning machinery. All-metal construction is liquid- and gas-tight, does not age, and has high corrosion resist ance. Available in copper bearing alloy for use with Freon or Methyl Chloride, or steel for Ammonia systems. SIZES: A in- to 4 in. inside diameters. BURST PRESSURES: 400 to 3,750 psi. ;|"` LENGTHS: Standard stock lengths, i Special lengths available on order. COUPLINGS: Stock units with male or J. female sweat fittings; also available with T male pipe thread fittings. v? REX-TUBE Flexible Metal Hose REX-WELD Flexible Metal Hose FOR Diesel engine exhaust lines Refrigeration tubing armor Air blower ducting Ventilating ducts Control wire casing Wiring conduit Suction hose General utility hose FOR Steam Hose Reciprocating flexible connections Refrigerant loading, unloading and charging Oil burner connections Pressure lubricating lines Conducting searching gases and liquids Diesel engine exhaust lines Misalignment correction Rex-Tube Convoluted Flexible Metal Hose Types have three basic formation patterns: square-locked, ball-bearing (or double-groove), and fully interlocked. Made of stainless steel, brass, steel, aluminum, bronze and other alloys. Packless and packed types. Sizes range from A in- to 12 in. inside diameters, and lengths to suit requirements. Rex-Weld hose types are manufactured from uniform wall tubing by a spe cial CMH corrugation-forming process. Metals used are steel, bronze, and other alloys. Rex-Weld sizes range from A "> to 14 in. inside diameter; with lengths and couplings to fit specific requirements. Especially designed for use under high temperatures and pressures, and where corrosive action is present. 1258 .... ... . -. . Pipe and Tube Ait Conditioning and Heating Piping copper and Copper Alloys COPPER AND BRASS INCORPORATED Executive office: 230 Park Avenue, New York 17, N. Y. HILLS--Baltimore, Md.; Chicago, III.; Clinton, III.; Detroit, Mich.; Los Angeles and Riverside, Calif.; New Bedford, Mass.; Rome, N. Y. . DISTRICT SALES OFFICES--Atlanta, Ga.; Boston, Mass.; Buffalo, N. Y.; Cincinnati, Ohio; Cleveland, Ohio; Dallas, Tex.; Dayton, Ohio; Grand Rapids, Mich.; Hartford, Conn.; Houston, Tex.; Indianapolis, Ind.; Miami,'Fla.; Milwaukee, Wis.; Minneapolis, Minn.; New York, N. Y.; Philadelphia, Pa.; Pittsburgh, Pa.; Providence, R. I.; St. Louis, Mo.; San Francisco, Calif.; Seat- le. Wash. . TUBE AND PIPE FOR GENERAL CONSTRUCTION Revere produces a wide range of Pipe and Tube for various industrial uses including condensers, aftercoolers and similar heat exchangers. The services of Revere Technical Ad visors are available without. obligation to assist Engineers, Designers and Con tractors in the selection of suitable Revere products for various appli cations. REVERE COPPER WATER TUBE For: Hot and cold water service lines Underground systems for water, oil. or gas . Drainage and soil piping Fuel oil and compressed air lines Heating systems--hot water and steam Radiant Panel Heating (technical book let, Design Procedure for Radiant Panel Heating available upon request). Revere Copper Water Tube does not LENGTHS, TEMPERS AND OPERATING PRESSURES Type K K L L M Temper Hard Soft Hard Soft Hard Pressure Standard Lengths Pounds Straight Coils up to400 12 and 20 ft " " 250 " " M 250 " " 150 " " 250 " __ 60 ft 60 ft STANDARD DIMENSIONS AND WEIGHTS Type K Type L Type M Size in In. k H k k H 1 lk 2 2k 3 3k 4 5 6 a e x>& .2 n c oM c AS<-> .2 =: 8 =8 .J fe = 8 eSM C 6& & .37 .500 .625 .750 .875 .035 .049 .049 .049 .065 .145 .269 .344 .418 .641 .030 .035 .040 .042 .045 .126 .198 .285 .362 .455 .025 .028 .032 1.125 .065 1.375 .065 1.625 .072 .839 .050 1.04 .055 1.36 .060 .655 .035 .884 .042 1.14 .049 2.125 .083 2.06 .070 1.75 .058 _2.625 .095 2.93 .080 2.48 .065 3.125 .109 4.00 .090 3.33 .072 3.625 .120 5.12 .100 4.29 .083 4.125 .134 6.51 5.125 .160 9.67 .192 13.9 .110 5.38 .125 7.61 .140 10.2 .095 .109 .122 .145 .204 .328 .465 .682 .940 1.46 2.03 2.68 3.58 4.66 6.66 8.92 rust. It is smooth inside and out, easy to install and bends and flares readily. There is no thread cutting; it takes solder or compression type fittings. Specifications: Federal: WW-T-799 ASTM: B88 REVERE DRYSEAL COPPER TUBE For: Air conditioning and refrigeration sys tems General service work Revere Dryseal Copper Tube is . de hydrated and sealed at the factory be fore packaging. It is soft and flexible and when flared for compression fittings, it does not split on the ends. Its ability to take smooth hand bends virtually elimi nates the need for fittings. 50 ft. Coils in sizes from % in. to % in. O.D., with wall thicknesses from .030 in. to .035 in., are packed in individual cartons. REVERE RED BRASS AND COPPER PIPE For: Piping systems in commercial, institu tional, municipal, and residential, con struction. Both are manufactured in standard pipe sizes--hence can be used with standard threaded or silver brazed fittings. Because of their extraordinary resistance to corrosion, they function with unimpaired efficiency even after many years of normal service. Specifications: Revere Red Brass Pipe meets the fol lowing specifications: Federal Standard: WW-P-351, Grade "A" Navy Department: 44P12, Grade "A" ASTM: B43 (Red Brass) Revere Copper Pipe meets the following specifications: Federal Standard: WW-P-377 Navy Department: 44P2 ASTM: B42 1259 Wolverine Tube Division of Calumet & Hecla Inc. 1417 Central Avenue, Detroit 9, Michigan Manufacturers of Quality-Controlled Tubing Sales Offices In Principal Cities Wolverine Trufin* and the WoIti Spun End Process! available in' C; through the Unifin Tube Co.t Lo; Ontario. CHOOSE WOLVERINE TUBE FOR ITS DEPENDABILITY ALUMINUM TUBING 1 Where conditions dictate the use of aluminum tube--because of its weight serving factor or for some other practical reason--there is one tube that will meet the supreme test--the Wolverine alumi num tube. The expert "know-how" that has been producing Wolverine nonferrous tubing, recognized for many dec ades for its top quality, brings you the same dependability in this aluminum tube. Its applications are varied, in cluding such uses as suction lines, radio antennas, furniture, etc. Made in pop ular sizes and wall thicknesses. COPPER WATER TUBE WOLVERINE REFRIGERATION TUBE Wolverine Refrigeration Tube has long been the standard of the industry. Rec ognized for its exceptionally smooth and dry interior.- Dehydrated, sealed, uni form soft temper. Moisture content well below minimum specified by ASRE. 50 ft coils individually packed in strong cartons. WOLVERINE TRUFIN* Type K--Recommended for air condi tioning, refrigeration, oil burner, plumb ing and heating installations, and under ground service. Type L--for oil burner, air condition ing, refrigeration and general plumbing uses. Type M--suitable for air conditioning and refrigeration installations and for interior plumbing and heating purposes. (Recommended only for use with sol dered fittings and non-pressure applica tions) . _ Types K and L furnished in hard and soft tempers; Type M hard only. Wolverine water tube is made accord ing to U. S. Government and ASTM specifications. For a complete list of data, ask for Form 575, Wolverine Trufin*--the integral finned tube. Presents wide range of outside-toinside surface ratios; more efficient and more economical than plain tube in many heat transfer applications. Saves space in all installations. Can be fabricated as readily as plain tube. In solid copper alloys, all aluminum and in bi-metal; iD variety of fin spacings, fin heights. TUBULAR PARTS WOLVERINE CAPILATOR* The capillary tube for restriction pur poses. Has record for outstanding per formance in metering control of liquids, gases and air. Seamless tube, smooth, clean bore, plug-Drawn consistent I.D. measurements, close tolerances, ends paper-wrapped. Available in both cop per and aluminum. Tubular Parts--made economically by Wolverine Spun End Processt which can produce one-piece forms with closed or partially-closed ends in one quick operation--saving production time, ma terial and assembly costs. With a background of over 36 years of exclusive tube producing, Wolverine, through its Field Engineering Service, can offer you much valuable technical help. Reg. U.S. Pat. Off. t A patented process RK.22465 1260 Air System Equipment Air Filters and Cleaners Air Devices Inc. Air Diffusers Exhausters 185 Madison Ave. New York 16, N. Y. Air Filters Filter Holding Frames t i7?rrWill R telROOUC TS" liil Industrial Furnaces Agents in All Principal Cities HOW IT WORKS High turbulence of many finely divided air streams is the keynote of Type FM air filter's new design. The media di vides the air into countless fine streams and throws those streams into violent cyclonic turbulence. Each little "cy clone" centrifuges its dirt particles against countless viscous-coated "wiping surfaces" which virtually scrub the air clean by catching and holding the dirt. There is no straining action, hence no clogging. The Agitair FM Filter is designed to perform at highest efficiency at an ap proach velocity of 432 fpm--or 1200 cfm through a 20 x 20 in. filter panel. The efficiency of the FM is higher than con ventional filters when operating at the lower design velocity of 288 fpm. ing principles, the high velocity Agitair Type FM permanent, cleanable air filter assures an amazingly high dust arresting efficiency and dust-holding capacity cou pled with sustained low resistance to air flow. This j>ennits the Type FM to re main in service from two to three times as long as ordinary 2 in. permanent, cleanable filters. Although these new fil ters do not have to be cleaned as often, particular attention has been paid to their design to make cleaning easier and more thorough. They can be restored to top efficiency easily and quickly. Rug gedly constructed to withstand the me chanical abuse of cleaning. Panels and frames are accurately designed to pre vent leakage around the filters. LOWER RESISTANCE The sustained low resistance of the Agitair FM means sustained peak volume of air for longer periods of time. . .no loss in'air volume. . .no danger of un loading. . .clean filtered air at all times. HIGHER DUST HOLDING CAPACITY Employing a new formula for air filtra tion 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 passages. . .less frequent servicing. . .lower mainte nance cost. LONGER SERVICE LIFE The Agitair FM Filter with its greater dust holding capacity, stays in service for longer periods of timej gives efficient per formance for months instead of weelaj or weeks instead of days. Less frequent servicing--and rugged construction combine to give the Agitair FM Filter a much longer serviceable life. 1/3 LESS SPACE REQUIRED The ability of the FM to filter, with efficiency, 50 per cent more air at the high velocity of 432 fpm reduces the filler panels required. Now I WO FM's will do the work of THREE ordinary filters . . . l/i less space required . fewer units to be installed . . . fewer units to be serviced . . . overall installa tion and maintenance costs reduced to a minimum. HIGH EFFICIENCY At the recommended velocities, the pffi *Sir has a high dust arresting mciency, which increases as the dust load is applied. Designed along entirely new air filter- TWO TYPES OF HOLDING FRAMES Individual type: Designed and con structed for easy handling in single unit installations, and to facilitate "on the job" assembly, into a multiple unit bank. Pre-Fabricated Type. Made of heavy gauge steel supports and delivered com pletely knocked down. They can be quickly and easily bolted together to form a sturdy panel bank. GREASE FILTERS Recommended for use in kitchens where grease-laden air is a fire hazard and a maintenance problem. Prevent grease from entering exhaust ducts, eliminate frequent duct cleaning, pro tect fans, greatly reduce fire hazard, and help maintain good ventilation. 1261 Air System Equipment and Cleaners Air System Equipment Air Filters and Cleaners CORPORATION 25000 Miles Rd. Cleveland 28, Ohio THE FILTER ENGINEERS Representatiees in all principal cities TYPES AVAILABLE--During the past 29 years, Air-Maze engineers have en countered and solved nearly every air filtering problem. As a result, a wide variety of engineered filter designs are available, including Electromaze elec tronic air filter, Automaze automatic air filter, and viscous impingement type panel air filters for ventilating, grease, railroad, aircraft and marine applica tions. EFFICIENCY--Efficiency of dirt arrestance of various filter panels varies with filter design, type of dust, amount of dust, method of charging filter with adhesive, etc. Specific information on any type of filter furnished on request. RESISTANCES--Filters available with initial resistances as low as .045 in. water at face velocity of 300 fpm. Re sistance versus velocity curves available on request. FACE VELOCITIES--Air-Maze offers filters designed to operate at peak effi ciency at velocities ranging from 100 fpm to 700 fpm. Recommended veloci ties for each type of-filter furnished on request. SIZES--Filter panels furnished in"accepted standard sizes and in special rec tangular sizes -,if required. Thickness varies with filter type. Most types fur nished in both 2 in. and 4 in. thicknesses but available in certain special thick nesses if required. HOLDING FRAMES--Holding Frames, complete with neoprene seals and choice of locking devices, available for use either singly or drilled for assembly into panel bank. CLEANING AND RECHARGING-- Permanent type filters easily cleaned by washing in hot water containing commercial detergent or with steam. Recharged by immersing in special ad hesive or SAE 30-50 oil. Complete in structions available on request. WRITE FACTORY for name of nearest representative or information on any type of filter. Representatives are in most principal cities. See classified section of your telephone directory. , ELECTROMAZE ELECTRONIC AIR FILTER For super-clean air, the Electromaze electronic air filter is the choice. It re moves particles as small as 0.1 micron diameter, has a rated efficiency exceeding 90 per cent, as tested by the National Bureau of Standards Discoloration Method. Collects smoke, fumes, pollens, and soot. AUTOMAZE AUTOMATIC AIR FILTER Where continuous operation without servicing is required, the Automaze automatic self-cleaning filter should be used. It combines a double filter panel curtain with a positive effective panel cleaning action to provide the best in viscous impingement air filteration wit" a minimum of maintenance. New sell contained drive mechanism and unitizeu. control system simplifies installation. Standard Automaze filter media is satis factory for most installations, but other media types are available for special applications. CORPORATION KLEENFLO For average-duty residential and com- mercialventilating applications. Panels are permanent viscous impingement type. Low initial cost. Available in 1 in., 2 in., and 4 in. thicknesses. . ` TYPE P-5 High velocity panel for handling air at low resistance. Recommended where space is limited. Available in 2 in. and 23^ in. thicknesses. 'Yjdely used in restaurant and hotel kitchens to trap airborne grease and re duce duct fire hazards. Available in either j 9ro^a11 angle assemblies or as indi vidual filters. 2 in. thickness only. . TYPE "B" . Heavy duty industrial filter for fresh air intakes. Has large dirt holding capacity, high efficiency, low pressure drop. Holds approximately 2 to 2J^ times more dust than conventional filters. Available in 2 in. and 4 in. thicknesses. fo?r:iy designed as a railroad filtei intake* e?uerT?ars anc* Diesel locomotive industrial*16 P,'.18 is also w`dely ir eentraHnioaPP l<iatl0ns where dust con- thicknessoffiy? ^ Availab,e in 4 in . DUSTAY Disposable-type panel for home furnaces and air conditioning units. "Wick action" provides 50 per cent more dirt holding capacity than ordinary throw away type filter panels. Available in 1 in. and 2 in. thicknesses. 1263 Air Filter Corporation 108G North Water St. Canadian Representative Milwaukee 2, Wis. DOUGLA8 ENGINEERING CO., Ltd. Monthilu. AIR FILTERS (formerly Aircor) Permanent-Cleanable GREASE FILTERS AIRSAN AIR FILTERS Industrial Domestic Commercial AIRSAN VIRO-CRIMP FILTER The specially designed high velocity Airsan Viro-Crimp filter core is viscous type and constructed of horizontal layers of galvanized wire mesh so arranged as to assure a large filter area with no ap . preciable pressure drop. Its exclusive Viro-Crimp is designed to operate at face velocities of 300-500 fpm at minimum resistance. Viro-Crimp edges are hemmed, an important safety feature that provides a smooth surface, extra rigidity and filtering area. Airsan Viro-Crimp filters are easily cleanable. Drain slots are provided, hasten drying and aid in cleaning. Air san Viro-Crimp Air Filters are of all metal construction throughout, the formed galvanized steel frames having full bronze welded corners and joints. Bulletin W 801. Airsan's expanded metal face plate acts as a lint arrestor to provide easier clean ing and servicing. It distributes &\r evenly over entire filtering area provid ing 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 to give maximum air resistance. All Airsan Filters have full bronze welded corners, galvanized steel frames and drain slots for quicker, easier cleaning. Airsan Air Filters are available in stand ard 1 in. and 2 in. thickness--Bulletin LS01. Also HEAVY DUTY filters for industrial and special applications in 2 in. to 4 in. thickness--Bulletin L401. AIRSAN GREASE FILTER ENGINEERING DATA Initial Resistance Rated Efficiency Type Ft (1 in thick) .060 in. w.g. at 288 fpm Type Fj (2 in. thick) .065 in. w.g. at 288 fpm Type D (2 in. thick) .09 in. w.g. at 288 fpm Type D (4 in. thick) .10 in. w.g. at 288 fpm Type W i 2 in. thick) .07 in. w.g. at 300 fpm Type W (2 in. thick) .012 in. w.g. at 500 fpm 98.5% 98' .5' % 985% 95.1% 97.9% AIRSAN HOLDING FRAMES Made of heavy gage metal complete with fireproof felt seal and locking device. Available in straight and V-banks. Pre fabricated with Airsan slip-groove con struction--eliminates felt between filter frames and cuts installation costs. Built to your specifications. Bulletin LS01 Permanent cleanable type Airsan Grease Filters specially designed for range cano pies, galleys, kitchens. Removes grease at source, reduces fire hazard in exhaust ducts and prolongs life of fans, motors and other mechanical equipment. Assemblies for mounting on ceiling or wall, single or multiple units--includes holding frames, support ing angles and end seals. Bulletin LS0S. Initial Resistance: .07 in. w.g. at 216 fpm Efficiency Rating: 98.5% Stand. Thickness: 2 in. Write AIR FILTER Corp. for Complete Bulletins 1264 Air System Equipment Air Filters and Cleaners American Air Filter Company^ Inc. 673 Central Avenue, Louisville 8, Ky. ' American Aib Filter of Canada, Ltd., Montreal., P. Q. MU THE COMPANY; The American Air Filter Company, Inc., is recognized in ternationally as an authority on air filtration and dust control. In 30 years, its leadership and scientific "know how" have been responsible for installations of AAF equipment in every industrial ized part of the world. Because its con tinuous research, high engineering stand ards and exclusive specialization have been consistently maintained, AAF equipment is used by leading companies in nearly every industry and is specified by leading architects and engineers for use in commercial and industrial 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. AAF's 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 con trol, or its Herman Nelson Division (see pages 1242-1243) on heating or ventilat ing problems. REPRESENTATIVE AAF PRODUCTS ELECTRONIC PRECIPITATORS: For air cleaning problems requiring super clean air AAF has developed three types of high-efficiency electronic filters. The complete line now available is the result of more than ten years of basic research and experimentation with electronic pre cipitation. It includes the self-cleaning Electro-Matic, the washable Electro-Cell with removable collector plates, and the Electro-PL with the replaceable Airmat Paper medium. These three electronic filters are now used extensively in both industrial and commercial installations. The wide range of applications has made available engineering data and performance char acteristics covering innumerable air cleaning and air volume requirements. This data simplifies materially the prob lem of specifications and selection of filter type. Electro-Matic Self-Cleaning Electronic Precipitator--The Electro-Matic Precip itator is an automatic electronic pre cipitator combining advanced principles of- electronic air cleaning with an ex clusive self-cleaning principle. It elimi nates the necessity of shutting down the filter for manual cleaning, minimizes the need for personal attention and permits continuous high-efficiency oper ation. It also allows the Electro-Matic filter to be built in standardized self- contained sections, easy to install and with all exposed parts of the filter casing electrically grounded for the protection of operating personnel. Send for Bul letin No. 50. 1265 American Air Filter Co., Inc. Air System Equipment Electro-Cell Electronic Filter Electro-Cell Electronic Filter--A plate type electronic precipitator offering sim plified design, improved performance and maintenance advantages. Built in verti cal sections 2-ft and 3-ft wide. Hinged ironizers extend the full height of the sections for easy access. Collector as semblies 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: An exclusive dry-type elec tronic air filter with charged Airmat collector element which combines air filtration and electronic precipitation in a single unit. Gives intermediate effici ency at lower cost, when the need for super-clean air is not indicated. How ever, it has twice the efficiency of un charged dry-type filters. Available in Straight Bank or "V" arrangement to meet virtually any space or capacity requirement. Send for Engineering Bul letin No. 257. Multi-Duty Automatic Filter provides outstanding features of performance and design and will accommodate either armored 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 ven tilation and air conditioning service. Available in any size or capacity. Send for Bulletin No. 2%1-A. AMER-glas Replaceable Unit Filters. A new viscous impingement type for eliminating atmospheric dust from forced air heating systems. The highly efficient filtering media consists of continuous, curled and interlaced, extremely fine glass filaments, bonded with thermo plastic to form a thick resilient pad. The pad is sprayed with a special Visco sine 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. Bit-A. Airmat Type PL-24--Airmat filters use standard Airmat medium, renewable af ter 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. Type HV-2 Filter; A high capacity, lowresistance unit designed for velocities up to 500 fpm. Exclusive pyramid pocket media design eliminates through-air pas sages ancl gives uniformly high efficiency oyer 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-ylas Disposable Filter American Type H V-S 1266 Airmat Type PL-H American Air Filter Co., Inc. Air System Equipment Air Filters and Cleaners AAF ROTO-CLONE DYNAMIC DUST PRECIPITATORS THE ROTO-CLONE is an exclusive, pat ented development of AAF combining the functions of exhausting, separating and storing dust in one simple, com pact, self-contained unit. Most types of dust collectors or separators are so large that they are usually installed out doors, which requires long pipe runs, increased power consumption, and higher installation costs. The Roto-Clone, however, eliminates expensive ductwork and reduces both installation and operat ing costs to a minimum. Available in a wide variety of types and sizes for either individual unit or central system in stallations and with wet or dry type collectors, the Roto-Clone has a proven record of economy and efficiency cover ing thousands of production line and individual applications. Write for pro fusely illustrated 35-page application and Engineering Bulletin No. 27%-A. Type D Roto-Clone--A dynamic precipitator designed for dry collection of granular industrial process dust. Combines func tions of exhauster, dust separator and storage facilities in one compact unit. High collection efficiency remains constant over entire pressure volume range. Adapted for individual unit or central system use. Capacities--from 100 to 15,000 cfm. Write for Bulletin No. 274- Type W Roto-Clone offers high dust separation efficiency where extreme fines and heavy dust loads are involved. Com bines dynamic precipitation with inte gral water sprays. Delivers a constant air volume and collects dust as a sludge. Compact design makes for easy, low-cost installation. Capacities from 1,000 +o 50.000 cfm. Write for Bulletin No. 274- AMERjet Type N Roto-Clone is a hydro-static col lector, with induced water scrubber. Re quires minimum space--easy to install. No moving parts, spray nozzles or pumps. Completely self-contained with dust dis charged as a sludge. Capacities--from 1.000 to 50,000 cfm. Write for Bulletin No. 277. Type N Roto-Clone AMERjet--A reverse jet type fabric arrester offering high collection efficiency, constant pressure drop (constant air volume), compact design and continuous operation. Other features are (1) tension control to compensatejfor variation in fabric dimensions, (2) rugged mechanism for dislodging col lected material with high pressure air jets and (3) venturi shaped inlet for dust-laden air which extends life of cloth. Available in range of capacities. Bulletin No. 279. AMERclone--A dry centrifugal dust collector designed to andle large exhaust volumes containing dust in high concen trations. Unit requires small space due to compact design and 1gh cleaning capacity of the AMERclone tubes. Abrasion resistant construction featured throughout. Collection effi ciency remains practically constant over wide range of exhaust volumes. Available in wide range of capacities. Write for Bulletin No. 291. 1267 AMERclone ' Air Filters / >* Air System Equipment Barnebey-Cheney Company Cassady and 8th Aves. Columbus 19, Ohio Air Recovery ACSC* Odor Removal Air Purification Solvent Recovery Activated Carbon* 1 AIR RECOVERY Air Recovery conserves costly conditioned air and reduces the amount of heating and/or cooling capacity required on new installations. Pur Air AIR RECOVERY equipment enables existing systems to handle increased ventilation load or a larger space without additional heating or cooling equipment. Substantial savings in fuel and power readily amortizes all installation costs. ODOR REMOVAL Pur Air ACSC Adsorbers continuously remove odors and gases by positive adsorp tion. By physically removing the odors--stale, stuffy "used" air is revitalized for fresh use. Pur Air ACSC Adsorbers will eliminate odor nuisances from fresh air in take, recirculated air, as well as air exhaust when air decontamination is desired. AIR PURIFICATION Air Purification removes airborne, vaporous impurities. Industrial wastes, process ing odors, combustion odors, atmospheric irritants and contaminants are removed from the air with ACSC Air Purification. SOLVENT RECOVERY We design, engineer, fabricate and erect complete, industrial solvent recovery sys tems. If you use a solvent that disappears into thin air, chances are we can recapture it for re-use. Let us explain. REACTIVATION Complete reactivation service for all types and grades of carbon in any existing nstallation. . PUR AIR ACTIVATED, COCONUT SHELL CARBON ADSORBERS Special, high activity (increased adsorptive and retentive capacity) activated coconut shell carbon has been developed`especially for air purification purposes. This high quality ACSC is available in a complete line of perforated, compact, easy to handle Pur Air Adsorbers designed to purify all types of enclosed spaces. The manufacturer of Pur Air ACSC Adsorbers and Units produces both the activated coconut shell car bon and the complete air purification equipment. This combined, integrated function permits Pur Air to offer the greatest 'protection in better quality activated coconut shell carbon at lower initial and maintenance costs. PUR AIR PANEL ADSORBER Pur Air ACSC Panel Adsorber permits installing the most carbon in the smallest space. For precision results, install one (1) Panel Adsorber per 100 cfm. Air re sistance only 0.30 in. (w.g.) Available in assembly frame components and also self-contained units. PUR AIR FILTER FOLD "FF" The Pur Air ACSC Filter Fold is a "pack age filter" that packs a lot of punch. In a small space--24 in. x 24 in. x 8% in.-- it recovers (deodorizes) 1000 cfm of "used" air. For Recirculated Air that has tobacco odors, body odors, etc., in homes, public buildings, theaters and all types of enclosed spaces. Model M for 1000 cfm Model D for 500 cfm Barnebey-Cheney Co. Air System Equipment uiamm ___________________________________ Air Recovery PUR AIR SALES REPRESENTATIVES Albany, N. Y., Associated Thermal Products, Inc. Albuquerque, N. M., Boyd Industrial Engineer ing, Inc. Amarillo, TeXm Snook A Adertoii, Inc. Atlanta, Ga., Crawley-Gorbandt Co. Baltimore, Md., Lancaster, May A Co. - Billings, Mont., L. W. Worthington Birmingham, Ala., S. C. Bratton Sales Engrs. Ltd. Boston, Mass., L. R. Geissenhainer Buffalo, N. Y., V. N. Harwood Co. Charleston, W. Va., Engineering Products Co. Charlotte, N. C., Robert E. Mason A Co. Chicago, 111., Zintel, Byfield A Co. Cincinnati, Ohio, Russell R. Gannon Co. Cleveland, Ohio, Dan B. Billington Columbis, Ohio, Russell R. Gannon Co. Corpus Christi, Tex., L. S. Pawkett A Co. Dallas, Tex., W. E. Lewis A Co. Davenport, Iowa, D. C. Murphy Co., Inc. Dayton, Ohio, Russell R. Gannon Co. Denver, Colo., E. P. Murr Des Moines, Iowa, D. C. Murphy Co., Inc. Detroit, Mich., George Q. McNamara Co. El Paso, Tex., Boyd Industrial Engineering, Inc. Ft. Wayne, Ind., Jones Engineering Products Ft. Worth, Tex., W. E. Lewis A Co. Hammond, Ind., Zintel, Byfield A Co. Hartford, Conn., Augur, Jones A Green Houston, Tex., Jack Thomas Davis Indianapolis, Ind., Russell R. Gannon Co. Jackson, Miss., Robert Porter Jersey City, N. J., Associated Thermal Products, Inc. Little Rock, Ark., J. C. Lewis Co. Los Angeles, Calif., Hess, Greiner <fe Polland Louisville, Ky., Russell R. Gannon Co. Lubbock, Texas, Snook A Aderton, Inc. Memphis, Tenn., J. B. Lemmons Miami, Fla., J. L. Middleton Co. Milwaukee, Wis., Zintel, Byfield A Co. . Mobile, Ala., S. C. Bratton Sales Engineers, Ltd. New Orleans, La., Robert Porter New York, N, Y., Associated Thermal Products, Inc. . ` Norfolk, Va., Laurence Trent A Co. Oklahoma City, Okla., O'Connor-Oklahoma Co., Inc. Omaha, Nebb., D. E. McCulley Company Peoria, III., Zintel, Byfield A Co. Philadelphia, Pa., George F. Bertrand Co. Phoenix, Ariz., Boyd Industrial Engineering, Inc. Pittsburgh, Pa., E. J. Dbckman Co. Portland, Ore., H. W. McKenzie Company Rochester, N. Y., A. R. Bowman Company Rockfobd, III., Zintel, Byfield A Co. St. Louis, Mo., Myers Engineering Equipment Co. St. Paul, Minn., E. J. Baker Company Salt Lake City, Utah, Williams, Gritton A Wilde San Antonio, Tex., L. S. Pawkett A Co. San Francisco, Calif., E. C. Cooley Co. Seattle, Wash., E. H. Langdon Co. South Portland, Me., A. E. Wallgren ' Spokane, Wash., Harold W. Frederick Co. Syracuse, N. Y., F. W. Chadwick Toledo, Ohio, Eyster Engineering Co. Tulsa, Okla., O'Connor-Oklahoma Co., Inc. Washington, D. C., Lancaster, May A Co. Wichita, Kan., O'Connor Industrial Equipment Co., Inc. ` M-15 CANISTER For replacement on existing systems. For new installations where canister-type ACSC equipment is specified. -- THROW-AWAY TYPE ADSORBER These disposable adsorbers are produced for package, unitized air conditioners . . . window, floor or automotive types. . Canister AIR FRESH'NER Purifies and removes odors from offices, toilets, hospital rooms, small laboratories, darkrooms, recreation rooms, etc. 65 cfm capacity serves up to 1500 cubic feet. PORTABLE UNIT Suitable for offices, recreation rooms, hospital rooms, labora Tkrovxncay type Adsorber tories, animal rooms, toilets, locker rooms, libraries, vaults, food coolers, etc. 500 cfm and 1000 cfm models available. FIXED MOUNT UNIT Complete line of self-contained units available for warehouses, industrial rooms, cold storages, etc. 12 sizes from 220 cfm to 2640 cfm. Air Fresh'ner Unit STANDARD EQUIPMENT Pur Air Adsorbers and Units are available to purify air and to remove odors in practically all occupied spaces. Efficient air recovery and removal are functions of selecting the proper Pur Air Adsorber for each application and available space. CUSTOM DESIGN Custom design and fabrication service is available for special requirements. Abnormal odor problems, industrial solvent recovery and compressed air filters are among the many proj ects handled. Inquiries are invited on any phase of air re covery, odor removal and air purification. Key personnel have security clearance for handling classified military docu ments. 1269 Fixed Mount Unit Air System Equipment Air Filters Carey Electronic Eng. Co. 1880 Clifton Ave. Springfield, Ohio Metal Wool Division. A-LUM-O-AIRE A-LUM-O-AIRE is a permanent type air filter designed for top efficiency in all forced air heating, air conditioning and ventilation applications. In 90 per cent of all applications oils or adhesives are not required. The filter is so efficient that the media of A-lum-o aluminum wool will catch and hold the dirt and dust. It is completely made of metal and is fireproof. Eiamea are constructed from aluminized steel. This material gives the strength of steel and the pro tection of an aluminum surface. Corners are welded for extra strength. Mat retainers are of heavy gauge ex panded steel and plated after cutting to size. The filter media is securely locked in place so it cannot slip or move, thus eliminating air and dirt from es caping past the filter media. The Metal Wool Division of Carey Electronic Engineering Co. has put many years of research into the development and methods of producing A-lum-o aluminum wool and copper wool and has thoroughly tested and proved its unusually high efficiency as a filter media. In a 20 x 20 x 2 filter there is an area of over 59 sq ft with millions of tiny barbs which effectively catch and hold the dirt. The aluminum wool consists of continuous strands with no short fibers. It is made from an aluminum alloy pro duced according to the specifications of Carey Electronic Engineering Co. for this purpose. A-lum-o-aire filters have been in industrial use many years and maintenance costs have proven it to be more economical. Many of them are in use in multiple banks where they can be washed clean in position. They are easily cleaned by flushing with cold water. A-LUM-O-AIRE filters are avail able in all standard 1 in. and 2 in. sizes. Special sizes made to order. Copper wool filter media with copper plated mat retainers also available. A-luin-caire filters can be loaded with the proper filter media to meet any specific indus trial requirement. Whatever your air filtration problems are, Carey Electronic Engineering Co., maintains one of the most modern laboratories and eng1* neering departments which is available to it's customers. WherPeh.oetovmeircryogoruaphlooof akl,umIninduumswtoryol,. Automobile Manufacturers, Air Conditioning, Of- Sees, Home Kitchen Exhaust Units, Warm Air Furnaces, Government, Electro Static Units, you will find A-lum-o-aire in use. 1270 tonrinEiiTBL Air System Equipment Air Filters and Cleaners HIR FILTERS Inc. tOUISVillE \. KY. AUTOMATIC, SELF-CLEANING Air Filters range in rated capacities from 3,220 cfm to 153,900 cfm (larger units are avail able) having an efficiency of 91.3 per.cent and a resistance of 0.28 W.G. Filters are the viscous impinge ment type. For details of patented media design see below. "Ferris Wheel" action of continu ous, rotating filter curtain eliminates, in back curtain, reversing filter cells to direction of air flow. Counter-air-flow flush-action in oil reservoir assures thorough self-cleaning of filter. The rota tion of the curtain is controlled by an automatic electric timer. E*ZWASH MEDIA used in Continental Filter Cells is a honey comb of die-formed, double corrugated metal strips. Efficiency of performance results from changes in direction and turbu lence created as air streams cross and recross each other while passing through the media. This insures retention of dust particles by the oil-coated surfaces. Low resistance results from relatively large, non-clogging passages. ------------ ----------- vui, uuiaau JJ u-naoil LUCUlft, lllay be thoroughly cleaned by a cold water hosing. No hot water, detergents, or special equipment are required. E*Z*OIL in handy spray bomb makes re oiling fast and simple. Filters are avail able with handles, latches, and holding frames for bank installations, and in 1 in., 2 in., and 4 in. thicknesses of popu lar sizes and capacities. Used without oil, these filters make excellent grease filters, or replacements for glass cells in air washeTS. NEW DYCON dry-type air filters have approximately 4 times the dust-holding capacity of other widely-used dry-type filters of similar size and efficiency. Efficient media is blanket of specially prepared synthetic fibers. Low maintenance cost: quickly and easily restored to like-new efficiency by vacuuming or cold-water rinsing. No oil involved. 1271 Air Filters Air System Equipment CONNOR ENGINEERING CORP. Danbury, Conn. Representatives in All Principal Cities Air Recovery lorex recovBry Air Purification In Canada: Douglas Engineering Co,, Ltd., Montreal, P. Q. WHERE TO APPLY AIR RECOVERY Air Recovery is simply the conversion of foul or stale air to fresh air. It has been used to advantage wherever air is conditioned to enhance comfort, raise production efficiency, extend food preservation or protect product quality. Depending on the source of contamination, Dorex Air Recovery Equipment has been installed to remove odors and other gaseous impurities from intake air, from recirculated air or from exhaust air. When applied to recirculated air, Dorex Adsorbers reduce the amount of uncon ditioned outdoor air needed for ventila tion and effect savings in installation and . operation costs. For example: Given an air conditioning requirement of an area of 20,000 cfm, of which it is assumed 14.000 cfm would be recirculated and 9.000 would be outdoor ventilation be fore installation of Air Recovery Equip ment, it may be possible to cut the amount of unconditioned outdoor air intake to 2,000 cfm by converting 4,000 cfm of used, already conditioned re circulated air to fresh air. Figured for average temperate zones, this 33J-6 per cent Toad reduction would lower the installation and operating cost substan tially because each 1,000 cfm of heated or cooled air that is converted saves: (1) 100,000 Btu of installed heating capac ity, (2) 2.6 tons of installed refriger ation, (3) 1,800 kw hours of current per cooling season, (4) 1,500 gallons of fuel oil or 9 tons of coal, and (5) incidental water consumption and maintenance. In existing systems, the application of Dorex Air Recovery Equipment will en able the system to serve a larger space or satisfy a greater conditioning load with out increasing, cooling or heating equip ment and without consuming more fuel or power. Pig. 9 Typical Canister Arrange ment--tide vteto Activated Carbon Traps Gases and Odors Activated^ carbon removes gases and odors by adsorption--a natural phe nomenon which takes place when air* home gases or vapors come in contact with it. An instantaneous condensation occurs and the condensed impurities are held tenaciously until the carbon is forced to give them up in reactivation* For air conditioning purposes, however, 1272 ,. . _. Connor Engineering Corp. the carbon must be especially processed, activated, and impregnated to meet the following specifications: (1) High ac tivity (adsorptive capacity) for a wide range of gases and vapors; (2) High retentivity over an entire range of normal operating conditions: (3) No retentivity for water vapor; (4) Extreme hardness to 'avoid dusting in handling and in service; (5) High apparent density (in the granu lar form) of not less than 0.45; (6) Adapt ability to repeated reactivation without appreciable loss in activity or reten tivity. In actual use, Dorex activated carbon has removed and retained 95 per cent of all gaseous impurities from the air passed through it and maintained that efficiency from six months to two years, depending on the air contami nation. Equipment to Suit Individual Requirements Dorex Air Recovery Equipment is available in a range of types and sizes to suit individual requirements. Each type is designed to hold the correct amount of activated carbon in a manner to provide a maximum area for decontamination, a minimum of air resistance and uniform air flow through the carbon. The average resistance to air flow ranges only from0.15 to 0.2 in. wg. TYPE H--Adaptable to Most Central Systems for Recovering the Freshness of Intake Air and Recirculated Air and for Eliminating. Exhaust Nuisances Type H Equipment--for complete de contamination of all air passed through ^ ons*sts of removable, perforated, carbon-filled canisters which are mounted in multiple on one or more supporting manifold plates. Fig. 1 snows a canister and its function; Fig. 2 shows a typical arrangement of canisters as installed. The flexibility of this ar rangement makes Type H Equipment readily adaptable to a wide variety of "Citations. Write for Bulletin .. _ . iui ruiero Air System Equipment andcieaoers Air Recorery Ftp. S. Dorex Type C Air Recovery Cdl Fig. i. Dorex G Pand TYPE C--Equipment for Recovering the Freshness of Recirculated Air. eaaif* ?yPf, ^ ^`r Recovery Cells were developed to meet a need for a large capacity, 24 in sS ec* an<* installed air purification unit. Each cell measures only 24 in. x ;th * 1' ^eep an<i completely purifies 1,000 cfm. They require no more engineertlwL. an . required for ordinary dust filters and can be mounted right along with ra in either flat or "V" arrangement. (Fig. 3) Write for Bulletin 117-C `"Package" Conditioners, Unit Heaters, Refrigerated Spaces, Airplane, at .'d TMway Car, and Marine Installations and Other Systems Where Space Is a Premium. Write for Bulletin 106-C TV exnn^mp?ct PaneIs consist of sturdy metal frames, each housing a battery of units of Perrrated metal tubes which contain the activated carbon. Standard fn. 1 one' *'wo or three tube rows in depth are available in a range of stock sizes or arrangement in air ducts. (Fig. 4) 1273 Air System Equipment an/cieam-s Dollinger Corporation Filters for Building Ventilation, Air'Conditioning, Engine Intake, Pipelines and Many Other Special Applications. Representatives in Principal Cities 6 Centre Park SshUI Rochester 3, N. Y. STAYNEW MODEL A-3 AUTOMATIC FILTER An endless curtain type oil-bath filter for handling large volumes of heavily dust-laden air at low cost. The effi ciency of Staynew Model A-3 is unsur passed among mechanical self-cleaning filters. Operation and Features: Doitble filter curtains (1) carried on heavy roller chains driven by sprockets keyed to the shafts of the curtain rollers (2). These rollers float cm ball bearings for quiet, frictionless operation. Curtains consist of removable panels (3) made of a single layer of bronze screen cloth to which are attached layers of woven copper mesh. The first of the curtains is the denser, having about twice the impingement sur face of the second or rear curtain. This first curtain acts as the filter and travels through the oil reservoir. The second curtain does not enter the reservoir, but acts only as a safeguard against oil en trainment. This design permits a direc Model A-S Automatic Filter (numbered featura ore referred to in accompanying description) tion of curtain travel such that cleaned panels (4) are always on the filtered air side. TAhUeCrIeCfioUrle^UnVo/ duuuwsvt cwaun.. be c--a--r-r-i-e--d across the back or return side of the front curtain to be blown off and carried on by the flow of air. Patented, exclusive Staynew Compressed Air Curtain Cleaners (5) arc available for special conditions. Specifications Model A-3 Filters are sectional and may be bolted together 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 K hp motor (7) driving through a reduction gear and a momen tary contact time switch (8) for testing and checking curtain travel and compressed air control. All are mounted on a common base plate (9) on clean air side of filter. Shear pin (10) is provided for protection of moving p&rts from accidental damag- Drive motor operates for a few seconds at 15 minute intervals, and compressed air curtain cleaners can be arranged to operate simultaneously. 1274 . Dollinger Corporation Air System Equipment Air Filters and Cleaners Handles nud latches STAYNEW PANEL TYPE FILTERS Model WKE: Dry-type finned panel filter for use in ventila tion and air conditioning systems. Extremely large filtering area in relation to overall 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 also 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. Unaf fected by temperature changes. Filter cells are held in rigid box-type supporting frames of heavy gauge metal by spring-loaded cam-type locking latches. Two lifting handles are provided on each cell. Filtering me dium supplied already crimped and cut to size. It may be in expensively 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. Viscous U.mIH DPV Panel and Frame Viscous Panel (Model DPV): A permanent type panel for air conditioning systems used in heavy duty industrial service. Filtering media consist of a series of layers of crimped galvan ized screen cloth and woven mesh. These media when coated with PD-10 Pingene Filter Oil form an unusually efficient filter. Model DPV filters are cleaned easily with live steam or by washing in a suitable 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. Electro-Staynew Electronic Filter: Ionizer and Collector Cell built into one compact unit. Highly efficient--removes 90 per cent of all air-borne dirt, including smoke, dust, pollen, oil mist. Available in single units of 1200 and 1800 cfm; any capac ity in multiple units. STAYNEW LIQUID FILTER _ , 1200 cfm cleclro'Slaijheu- Precipitator Model ELS: Widely used for the filtration of cooling water to prevent clogging of spray nozzles. Exclusive, low-cost SLIP-ON INSERT easy to remove, clean, replace. Radial Fin Construction provides all possible filtering area in smallest possible space. Standard modelsilab avale to handle up to 1000 gpm. Model ELS (Sectional View) Representatives in Principal Cities Complete Information from Factory on request FILTERS FOR INTERNAL COMBUSTION ENGINES. COMPRESSORS, PIPE LINES; ALSO DUST COLLECTORS 1275 Air System Equipment Air FateTM Chicago Farr Company manufacturing Enginsets P.O. Box 10187, Airport Station Memphis LOS Angeles 45, Calif, Manufactured under license by Farr Co. Mfg. Ltd., Montreal, Canada ; ' > New York > V FAR-AIR FILTER AND HOLDING FRAME A high velocity, low resistance, viscous impingement unit for industrial and commercial applications. Available in a wide range of types and sizes for dirt, lint, grease, entrained water, ink, paint, etc. Herringbone-crimp media design assures higher performance, larger dirt holding capacity, lower pressure. loss, easier cleanability and reduced main tenance costs. Standard interlocking holding frames are 16 gage steel, baked enamel finish. FAR-AIR CAPACITIES Recommended net face velocity is guide in ..estimating FAR-AIR Filter 519 fpm although velocities up to 700 requirements. 4 in. filter thickness has fpm may be used. The following chart is a twice the pressure loss of the 2 in. NET FACE VEL. F.P.M. CAP. C.F.M. Per Sq. In. PRES SURE LOSS CLEAN In. HiO V #44 m 2.40 390 2.70 433 3.00 476 3.30 519 3.60 563 3.90 4.20 650 4.50 693 4.80 0.06' 0.07' 0.09' 0.10* 0.12' 0-14' 0-16' 0-19' 0-21' NOMINAL FILTER SIZE Standard Stocked Filters Other Common Sizes 16* x 20"| 16* x 25'| 20* x 20"| 20 x 25* 10* x 20--116" x 16--| 20' x 30-| 25' x 30" FILTER CAPACITY CUBIC FEET PERTmINUTE 700 860 935 1015 1170 1250 795 895 995 1095 1195 1290 1390 1490 1590 800 900 1000 1100 1200 1300 1400 1500 1600 1020 1145 1275 1400 1530 1655 1780 1910 2035 360 . 485 405 550 450 . 610 495 670 540 730 585 790 630 855 . 680 915 725 975 1235 1390 1545 1700 1855 2010 2165 2320 2475 1575 2365 2560 MEDIA DESIGNATION AND APPLICATION Type 44: 14 mesh zinc-electroplated chromate before and after assembly. steel screen. For ventilation, paint, Frame hot dip galvanized. Marine lint, ink, oil. ventilation application. Type 44F: Coated with vinyl or other Type C4C4H: All copper media and special paint. For fume-resistant ap filter frame. Corrosive atmosphere and plications. . water elimination applications. Type 44G: Standard filter, unoiled. Type A4A4: All aluminum media and For grease arrestance. filter frame. Stainless steel and monel Type 44MZ: Screen painted with zinc filters for special applications can be Trade Mark Reg. supplied on special order. 1276 Farr Co. Air System Equipment Air patera HOW TO SPECIFY STANDARD TYPE 44 FILTERS & FRAMES Filter shall be permanent, impinge ment, washable, all metal, panel type. Media shall be zinc electroplated, 14 mesh steel screen, arranged in alternate layers of flat and herringbone-crimped screens, so that at no point is air flow restricted to flow through the screen, .4 layers of each per inch, -in. rod reinforced, and enclosed in a frame of 16 gage steel with flush mitered corners. Resistance to air flow of a clean filter shall not exceed 0.12 in. w. g. at 3.6 cfm per square inch of net face area. Holding frames shall be factory built on 16 gage steel "T" section, bonderized and bake enameled, with felt air seal, interlocking edges, and filter locking device. Filters shall be Far-Air Type 44 and frames shall be Far-Air Standard Inter locking as manufactured by Farr Com pany, Los Angeles 45, California. ROTONAMIC SELF WASHING FILTERS ROTONAMIC The Rotonamic is a compact, multiple tube, cyclonic type air cleaner with continuous dirt removal by air bleed. Efficiency averages 98 percent on 5 to 10 micron dust of 2.5 specific gravity. Efficiency is even higher on larger parti cles or on denser material. Rating of 20 x 20 x 4in. panel is 1000 to 2000 cfm depending on available pressure. Ap parent straight through air flow requires no difficult change in duct direction. Bleed off piping is simple. Deflecting vanes form a high velocity vortex in each tube. Internal reversal of the direc tion of flow doubles the cyclonic action, producing the high efficiency. These completely automatic units wash and re-oil themselves on any frequency cycle desired. Each is made up from 4 in. thick corrosion-resistant filters in combination to meet any cfm require- ?e*nj hashing water and contami nated oil is immediately flushed away, eliminating messy sludge and oil sumps, jnere is no oil entrainment. Each unit r* a ,?a^ety deluge valve that auto matically prevents fire from passing inp Umt/ Installation is simple and ENDLESS GREASE ELIMINATORS FAR-AIR Endless Grease Eliminators halt the deposit of highly combustible grease and lint in the air ducts, reduce maintenance, protect blower and fan, provide better ventilation and sanita tion. Available in sizes and types to meet any cfm requirement. Full catalog and technical ihforma- tion on any FAR-AIR product is avail able on request ... or see Sweet's Archie tectural File. . 1277 Air System Equipment Air Filters Glasfloss 155 E. 44th St., New York 17, N.Y. Glass Fiber, Disposable Air Filters For All Forced Air Heating, Ventilating and Air Conditioning Systems <- GLASFLOSS I-S AIR FILTER Recommended for maximum air cleaning efficiency. To the GLASFLOSS Stand ard Filter pad of long, fine glass fibers has been added a strainer mat (see sec tional illustration at left). The com bination of these two elements brings air filtering efficiency to as high.as 95 per cent. Resistance to the passage of air is normal. GLASFLOSS STANDARD FILTER -* This type of filter is most widely used for home heating equipment and normal industrial installations (see illustration at right). The long, fine glass fibers provide a greater surface area to hold more dust. Extremely low resistance to passage of air. Available in all standard sizes. GLASFLOSS ROLL-PAK Carefully planned for bulk users and for economy. Filter pads are cut to size from standard rolls, 40 in. wide to ft long and either 1 in. or 2 in. thickness, then fitted into permanent fra-ro^The result in saving is as much as on per cent of air filter costs. Changes can be made quickly and the fluffy, hne glass fibers are easy on the hands. For Complete details, write Dept. HVG-54 1278 Air System Equipment Air cleaners The Goodyear Tire & Rubber Company, Inc. Akron 16, Ohio PLIOTRON* AIR CLEANER SELF-CHARGING ELECTROSTATIC WASHABLE PERMANENT TYPE WHAT IT IS PLIOTRON is a self-charging, electro static, washable, permanent-type air cleaner. Revolutionary feature is its new filter medium of shredded polyethylene. Sound engineering and construction in sure long life and minimum maintenance. HOW IT WORKS Shredded polyethylene carries inherent positive and negative charges in close proximity to each other. These charges are greatly increased with the passage of air. Since particles of dirt are simi larly charged, the meshed plastic does an effective job of attracting and capturing them. SPECIAL SHREDDING INCREASES EFFICIENCY A special method of shredding produces a feathered edge with thousands of cilia like serrations. These increase the area exposed and create a heavy turbulence that brings the dirt particles into inti mate association with the statically charged polyethylene. AVAILABILITY INFORMATION PLIOTRON is supplied through dis tributors located in every major market ing center across the country. It is presently available in four standard sizes, all 1 in. in thickness. It is so de signed as to stay in the general resistance range of ordinary, 2 in. thick, impinge ment filter, yet do a superior job of air cleaning. Spacer clips which are . also available, or another PLIOTRON, are recommended in instances where a filter greater than 1 in. in thickness is required. Filter Size Nominal 16 x 20 x 1 16 x 25 x 1 Net Face Static Pres Actual 15*%6 x 19 151%6 x 24 Velocity sure Drop % x .938 %6 x .938 fpm Inches HjO Sq Ft (Net Area) 2.22 2.78 20 x 20 x 1 19% x 19 % x .938 2.78 200 300 375 450 500 __ 600 0.08 0.15 0.22 0.30 0.36 0.48 445 665 830 1000 1110 1330 Filter Capacity cfm 555 835 1040 1250 1390 1670 555 835 1040 1250 1390 1670 PLIOTRON--T.M. The Goodyear Tire A Rubber Company, Akron, Ohio 1279 20 x 25 x 1 19% x 24 %6 x .938 3.47 695 1040 1300 1560 1735 2080 Avt System Equipment - ^/aSSTer* Owens-Corning Fib ERG I.AS Corporation Toledo 1, Ohio REFILLABLE ACTIVATED CARBON RECOVERY CANISTER TYPE "C"--CANISTER, a perforate metal cylinder filled with granular car ibon (for 15 to 35 cfm each with recom mended maximum of 25 cfm). Made up of one perforate metal cylinder within another, with the side walls of the two forming an open area which is filled with granular activated carbon. The top is completely sealed with a eap that en closes both the inner and outer shell. Air flows through the cylindrical side THE ALL-PURPOSE, REPLACEMENT-TYPE AIR FILTER wall and carbon bed, into the hollow Air flows freely through a Fiberglas Dust-Stop* Air Filter, 0* ISOM CMIU center of the inner cylinder--then down yet virtually all dirt is trapped inside. Correctly sized fibers PERFORMANCE CHART C-4 Cfm Pressure Loss* through the opening punched manifold plate upon which it rests. mean peak efficiency . . . minimum resistance. "Depth-load ing" extends filter life. (Inches W. G.) 5 0.02 The Canisters may be set on the mani THE FILTER 10 0.045 fold plate in any arrangement that best Dust-Stop Air Filters are impinge Resistances ; 15 0.075 20 0.11 25 0.15 30 02 suits the requirements and available space.' Canisters and/or manifold plate ment-type filters constructed of glass fibers which are non-absorptive, fire proof and will not shrink or swell. Resistance--inches, water gauge 300 fpm 450 fpm 35 025 40 0.32 * Resistance is overall can be furnished in stainless steel, brass or aluminum for special installations. Fibers are coated with a non-evaporating odorless adhesive which effectively traps 1 in. filter .080 2 in. filter .135 .170 .300 NU-AIR TYPE "A" AIR RECOVERY UNIT The Type "A" panel Air Recovery unit handles from 700 to a maximum of 1000 cfm. For use in removing odor and gaseous impurities where those concentrations-are light to medium. The shape of the carbon bed offers a great exposed dust, lint and pollen. Dust-Stops are replacement-type filters and should not be laundered. Uses--Dust-Stop Filters may be used at approach velocities up to 450 fpm with out impairment of their high efficiency characteristics but with higher resist ances. Maximum permissible resist ance of filters is 1)^ in. water gage. In cases where velocities approach 450 fpm, care should be taken to see that fan capacity is adequate to overcome . increased resistances. Cfm Capacities--Rated capacities of standard 20 in. x 20 in. Dust-Stop Filters are 800 cfm at 300 fpm velocity and 1250 cfm at maximum permissible velocity of 450 fpm. area to the air flow for maximum effi DUST-STOP FILTER FRAMES ciency. The carbon bed is formed by two parallel sheets of perforated metal, fashioned in a series of S-curves, com prising the Surface through which the air flows. Both types of equipment can be used in single or multiple units for required capacities. Complete technical data available in new bulletin 15-CX, 15-DX by writing the manufacturer. PERPORMANCE TABLE CFM Static Pressure Loss* (Inches V-Arrangement Flat 500 600 700 800 900 1000 1100 1200 1300 . 0.105 0.15 0.177 0.23 0.275 0.33 0.377 . 0.08 0.105 0.13 0.17 0.19 0.23 0.26 0.3 0.345 1 Resistance is overall. Dust-Stop Filter Frames are designed for the convenience of the engineer in constructing filter banks. Metal frame is of universal style, suited to use in flat or "V" banks. Designed-in, self-lock ing 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 galva nized finish. Front, back and side angle uprights for V-bank assembly are also offered in 20 in. increments up to 160 in. length. ' DUST-STOP RESISTANCE INDICATOR The Dust-Stop Resistance Indicator acts as a guide to economical bank main tenance. With adjustable filter-change be changed, this indicator provides a guide to "when-to-change filters." In marker set at resistance level specified sures operation at rated capacity and fiy engineer as point where filters should efficiency. TMorRaG^t"ni55T-STPare trade-m^fa (Reg.U.S.Pat.Off.) of Owens-Corning Fiberglas Corpora- " variety of producta made of or with fibere of glass. * 1280 1281 Air System Equipment tSi ci<Sm jH. ft. H. J. Somers, Inc. -G0G3 Wabash Ave., Detroit 8, Mich. Agents in All Principal Cities 4* fc All Welded Vee Type Patent No's. 200S800. 2130107 Somers Hair Glass Filters provide everything required in an efficient air-cleaning system. ' Consider These Features High rating for dust, soot and bacteria separation. Require no adhesive, coating or impreg nation. Indestructible in normal service. Minimum low-pressure drop. Odorless and non-absorptive. Fireproof. Washable. Permanent-"Ho not rot nor disintegrate. All welded zinc-plated 20 ga. steel frame. Metal protection strip on apex. Glass cloth between hot-dipped hard ware cloth. Glass ribbon seal so air cannot short circuit. Somers Hair Glass Filters consist of a 20 gauge hot galvanized frame holding gal vanized wire cloth packed with hair-spun glass strands. The glass strands are flex ible, do not break up and cannot be drawn into air stream. Hair Glass being chemically inert, has no facility of absorption; it cannot rust and lasts indefinitely in service. Water either hot or cold may be used to clean it, without impairing its efficiency. These filters eliminate the necessity, the expense and the inconvenience of periodic replacement. 1282 H. J. Somers, Inc. Air System Equipment Air Filters and Cleaners SOMERS WASHABLE AIR FILTERS All Welded Vee Type Stock Sl2es Frame Size Height and Length 8* * ir 12* x w ir x 20' 15K* x24*' 15H* x24*' 15W x24*' 15H* x24H' 16' x 20' 16' x21*' 16' x 25' 16' x 25' 16' x 25' 16' x 25' 16' x 25' 16' x 25' 16' x 25' 18* x 18* 18* x 18* 18' x 24' iw x IW' 1W x 19** 1W x 19*' 19M' xl9H' 19H* x 19*' 19H* x 19*' 19H' X 19H' 20* x 20* 20* x 20* 20' x Vf 20' x 20' 20' x 20T 20' xVf 20* x 20* 20* x 20* 20* x 20* 20* x 25' 20* x 25' 20' x 25' 20" x 25* 20* x 30* 20* x30H' ' 23' x 20* 23*' x 23*' 23K' x 17*' 24' x25H' 25' i 20* 26' x23H* 26' x23H' 26* *34' 28' x 33H' W x33H' 30* x 15' 30* x 20* 30* x 24' 31' x23YaT Frame Depth 3*' 2*' 3*' 3H' 3*' V 3*' 2* 3' 2* 2*' 3' 3*' 3*' 3H' 3H' 3V6' 3*' 3' 2* 3' 3' 3' 3*' 3*' z%r V . 2H' 2*' ws 3' W 3*' 3H' 3H' V mm 3*' w 3 W 3H' 3*' 3' 3*' 3*' 2W 2%r 3*' 2*' 3H' 3*' 3H' 3' 3*' Filter Surface Square Inches 288 288 720 1023 1674 480 1110 384 816 480 624 864 1344 1440 1632 1056 864 1134 1080 480 819 936 995 1053 1170 1696 480 600 780 840 960 1020 1200 1320 1680 600 1020 1560 1800 1800 2400x 1656 1621 1068 1872 1800 936 936 2652 1428 3045 1800 1800 1800 3162 For Average Dry Filter Installations 288 C.F31. 288 C.F.M. 720 C.F.M. 1023 C.F.M. 1674 C.F.M. 480 CF.M. 1110 C.F.M. 384 C.F.M. 816 C.F.M. 480 C.F.M. 624 C.F.M. 864 C.F.M. 1344 C.F.M. 1440 C.F.M. 1632 C.F.M. 1056 C.F.M. 864 C.F.M. 1134 C.F.M. 1080 C.F.M. . 480 CJ.M. 819 C.F.M. 936C.F.M. 995 C F.M. 1053 C.F.M. 1170 C.F.M. 1696 C.F.M. 480C.F.M. 600 C.F.M. 780 C.F.M. 840 CJ.M. 960 C.F.M. 1020 CJ.M. 1200C.F.M. 1320 C-F.M. 1680 C.F.M. 600C.F:M. 1020 C.F.M. 2560 C.F.M. 1800 C.F.M. 1800 CJ.M. 2400 CJ.M. 1656 C.F.M. 1621 C.F.M. 1068 C.F.M. 1872 C.F.M. 1800 C.F.M. 93fi C.F.M. {36 C.F.M. 2652 C.F.M. 1428 C.F.M. 3045 CJ.M. 1800 C.F.M. 1800 C F M 1800C.S.M 3162 C.F.M Wet Application 144 C.F.M. 144 CJ3I. 360 CJM. 511 CJJJ. 837C.F.M. 240 C.F.M. ' 555CJ.M. .192 CJ.M. 408 C.F.M. 240 CJ.M. 312 CJ.M. 432 CJ.M. 672 CJ.M. 720 CJ.M. 816 CJ.M. 528 CJ.M. 432 C.F.M. 567 CJ.M. 540 CJ.M. 240 CJ.M. 409 CJ.M. 468 C.F.M. 497 CJ.M. 526 C.F.M. 585 C.F.M. 848 CJ.M. 240 CJ.M. 300 CJ.M. 390 C.F.M. 420 C.F.M. 480 C.F.M. 510 CJ.M. 600 CJ.M. 660 CJ.M. 840 CJ.M. 300 C.F.M. 510 CJ.M 780 C.F.M 900 C.F.M. 900 CJ.M. 1200 CJUf. 828 CJ.M. 1810 C.F.M. 534 CJ.M. ' 936 CJ.M. 900 CJ.M. 468 CJ.M. 468 C.F.M. 1326 C.F.M. 714 CJ.M. 1520 CJ.M. 900 CJ.M. 900 C.F.M. 900 C.F.M. 1581 C.F.M. Other sizes also available. Send for complete stock size list. Frames zinc plated for 100 hour salt water spray test. Refill may be inserted if necessary. Quotations and further engineering data, including master holding frame drawings will be sent on request. Just a few users of Somers Filters Chemical Plants: American Viscose Co., American Zinc & Chemical Co., Celanese Corporation, Davison Chemical Corp. Automotive: Cadillac Motor Car Co., Chevrolet Motor Car Co., Chrysler Corp., Fisher Body Corp. Refrigeration and Air-Cond.: Frigidaire '-orp Norge Div.--Borg Warner Kelvinator Corp., York Ice Machine Co. ohips: Amer. Shipbuilding Co., U. S. S. baratoga, U. S. N. Lake City, Fla., U. S. Daytona Beach, Fla., U. S. N. Vero ^a*> U. S. N. Jacksonville, Fla., utilities and Municipalities: City of tvenosha, Michigan Consolidated Gas Co., Detroit Edison Co., New York Edi son Co., Westchester Lighting Co., Dep't. Stores: S. S. Kresge Co., S. H. Kress & Co., Food Processing: Awrey Bakeries, Gil bert Chocolate Co., Kellogg Co., Manufacturers: Buffalo Forge Co., Bur roughs Adding Machine Co., Clarage Fan Co., Curtiss-wright Airplane Co., Glensder Textile Co., Hoover Co., Inter national Heater Co., Kearney & Trecker Corp., Kilian Mfg. Co., National Carbon Co., Inc., Pittsburgh Plate Glass Co., Rockford Machine Tool Co., Sunstrand Machine Tool Co. 1283 Air System Equipment *ir Ritas Research Products Corporation Madison 10, Wisconsin AIR FILTERS FOR HEATING AND VENTILATING Greads Kilters for Kitchen Exhaust Systems--Point Arrestor Pads \ \^NXf v \ 1 A>v /. XX VVXnA''vXVv' V\V\AAA<WVv V />sV \ \ vWs \ AV R3? AIR FILTERS Controlled turbulence design is pro vided in every RP filter. Scientifically staggered baffles cause thousands of sharp reversals of air flow in the filter. Media gradation, insures RP depth loading, an important longevity feature. Air borne particles are centrifuged against the baffles and are held by adhe sive in the air filter and by the viscous qualities of the particles, themselves, in the grease filter and paint arrestor appli cations. Constructed of slit and expanded ma terial, RP filters are uniform in con struction and performance. REPLACEMENT WASHABLE "5mxp-/n" Grid Atr Fitter Installation Showing Sdf || Seal Edge. Fiber Self-Seal Air Filter The highly efficient, soft; resilient, non-fracturing RP replacement .media isheld in a sturdy, refillable wire grid. Media pad is oversize and no channel is required or used on edge which provides the self-sealing feature. Used in domestic and commercial units and in central sys tem filter banks. Available in in., 1 in. and 2 in. thicknesses in standard and E Z Kleen Air Filter The RP Alumaloy, E Z Kleen Air Filter is an economical selection for many ap plications. Like all RP washable air filters, this filter is extremely easy to clean. Industrial Air Filter RP Alumaloy Industrial air filters are multi-velocity filters, which have, ex tremely low initial resistance and slow build-up resistance. Holding frames for filter banks, combination lift and lock handles, lift handles and water soluble filter coat adhesive are available. Grease Filter Efficiency in excess of 99 per cent on grease vapors, gleaming appearance, ease of cleaning and light weight have made RP Alumaloy Grease Filters a volume performance leader in its field. A free comprehensive data booklet pn kitchen exhaust systems is available. special sizes. Snap-In Grid Air Filter Designed for central system use of the inexpensive Fiber Self Seal Pad. Paint Arrestors Specially designed, inexpensive and efficient pad removes overspray from paint spray booth exhaust air. Snap-in RP Alumaloy Air FiUrr and Inset Showing Handle grid retains pad in frame. Lock ODOR REMOVAL . Exclusive RP Combination dust and odor removal is available in the D-0 Air Filter--a replaceable filter--and with D-0 Kote, the dust and odor removing aohesive for application to RP alumaloy washable filters. 1284 Air System Equipment At Fnters TRION, INC. 1000 Island Avenue, McKees Rocks, Pa. In Metropolitan Pittsburgh TRION ELECTRONIC AIR CLEANERS (Electrostatic Precipitator) ELECTRONIC AIR CLEANERS remove more than 90 per cent of dust, dirt, Hnot P? *en an<* a*r-krne bacteria from air streams {National Bureau of Standards fiiti1 SIr test method). Trion manufactures a complete size range of electronic air wrs for residential, commercial and industrial applications as follows: ASSEMBLED UNITS for commercial and industrial use. Complete unit Sl1. ra\' lonizing-collecting cells for specified cfm at required cleaning effi- inHJCyi- power pack(s) of proper size and capacity, complete with rectifier tubes, atJng instruments and magnetic circuit breaker; (C) complete water-wash clean- mft *e?' built-in bank of water proof, dry type mechanical after-filters; (E). .rf/xn?^ 8tee^ framework, factory assembled, then matched-marked before ship /ta fT'. ' floor interlock and time delay screws; (I) "Danger High-Voltage" sign: v ) non name plate; (K) all high voltage cable and connectors. tinna "PACKAGED" UNLTS are advantageous in smaller installa- where space isiimited. Models up to 9330 cfm are constructed to specifications complete package, including drain pan and access door. "PACKAGED" UNITS for residential and small commercial use are aaspmki6 from stock in 4 sizes up to 4000 cfm at 90 per cent efficiency. Shipped fully rieht n i nCOm^ete a(^aPters, interchangeable to accommodate air flow from EQUIPMENT designed and manufactured to meet specific re- ajr TMe,n,t3 ` by-product recovery, nuisance elimination, general purification of . i 5?es- Design takes into consideration pressure, temperature, corro- slon, oirt-loadmg, removal of collected dirt. ' 1285 Air System Equipment At F`H .vfe? CESE3> Vortox Company Claremont, California CSSI Panel Air Filters for all Industrial Applications 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. | k' OPERATION. Numerous changes in direction of dust laden air cause the dust particles to irdpinge on the ad hesive viscous-coated surfaces of the Vortox Type VR Panel Air Filter illus trated above is the type used on engine intakes and in car bodies of diesel loco motives. It is constructed to withstand the severe usage of locomotive service. It has the exceptional characteristics as in all types of Vortox Pane! Air Filters. FILTER ELEMENT. Fabricated of elastic units of fine steel wire positively interlocked to provide a permanent filter, the element offers many advan tages: (1) In a 2 in. x 20 in. panel there are from 9300 to over 15,000 feet of fine steel wire, depending upon the type. (2) Even distribution of filaments ex poses innumerable viscous-coated sur faces to the air stream, thus obtaining the most effective cleaning for space occupied. (3) Proper spacing of fila ments prevents clogging and assures maximum dust removal efficiency. (4) Structural strength and permanent re silience combine to withstand "packing" effect of vibration and pulsation. filter element. Coarser particles collect near the entrance, while finer 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 distributing 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 Panel Inches* 16X20X2 16 X 25 X 2 20 X 20 X 2 20 X 25 X2 Actual Outside Dimensions Inches 15| X 19 15| X 24 191 X 19 19i X 24 XH XH X li X 11 Capacity Range In CFM** 640 to 950 800 to 1200 800 to 1200 1000 to 1550 Outside Dimensions Of Holding Frames Inches 161 X 201 X 2 161 X 251 X 2 201 X 201 X 2 201 X 251 X 2 These filters are also made in 4-in. thickness. . Some filter manufacturers specify very high velocities which are applied to certain internal dimensions o> the filter. The range of capacities stated above are computed on the basis of average to high velocities applied to the total filter area the actual outside dimensions of Vortox Panel Air Filters. 1286 Air System Equipment Air cleaners Westinghouse Electric Corporation Slurlevanl Division Air Conditioning, Heating, Ventilating, Dust Control and Fume Removal Equipment, Electronic Air Cleaners, Compressors. Mechanical Draft Equipment Hyde Park Offices in Principal Cities EoStOll 36, MfiSS. ELECTRONIC AIR CLEANING PRECIPITRON high efficiency elec tronic cleaners save money by removing harmful dust and dirt from ventilating air. In commercial buildings PRE CIPITRON catches dirt and grime before it settles on walls, merchandise, light fixtures and equipment. In in dustrial plants PRECIPITRON protects valuable equipment, prevents product spoilage and improves working condi tions. , Encased Precipitron Horizontal Airflow- Horizontal and Vertical Air Flow Manual wash type for installation in ducts. Sizes range from 1200 to 100,000 cfm for operation at 90 per cent efficiency by Blackness Test. Units easily main tained by manual washing. Uses 115 . volts single phase power--only 40 watts per 1000 cfm. Push-Button washing type, washes and applies adhesive with a built-in motorized moving'nozzle washing mech anism operated by remote control. Allows operator to service the unit5 quickly and economically from outside the duct. Sizes from 5000 to 72,000 cfm. Automatic Washing type for large, heavy duty applications. Washes and applies adhesive automatically without interrupting the air flow. Mobile washer boxes isolate small section of unit for complete servicing. Capacities from 24,000 cfm up. Vertical Unit for up or down, air flow --manual washing. Suited to small and medium size installations where floor apace is at a premium. Capacities 1200 to 9600 cfm. Commercial Precipitron With "Push-Button" Wash Home Unit Oil Mist Control Unit Oil Mist Control Units Designed to collect oil coolant mists generated by high-speed cutting, grind ing or machining operations. Have builtin fan for individual machine ventilation. Available in 600 and 1200 cfm capacities. Home Unit Designed for residential use when con nected with forced warm air heating system. Two capacities: 1000-1200 cfm and 2000-2400 cfm; efficiency 90 per cent. Uperates from house current. 1287 Commercial Vertical Airflow Unit Air System Equipment Air Fiiten^: Wilson & Co., Inc. AIR FILTER DIVISION 4100 S. Ashland Ave. Chicago 9, Illinois HA[RWILSONS FI LT E R P-M * 4 ' * -> < * -X i P 4 .>-4" X' X r* > * 4 V- 4 ` X >- 4 >< . 4 M'l * ' x- v4 X >4 < h. -< -< > < : n >-4 y-4. vw M v a >< v- v V-4 4 fc- -< `>-4 .?* A >-4 >,4 ` >-*< . :<_ . - ~<-W > V4. V 4 , v^< ; y< x X M- *<, *.<' vv-> >-4 V.4 * V'K-"- V r-^. ' . . X The Popular WILSON HONEYCOMB Here you have the popular HONEY COMB air filter. Embodying the cus tomary fiber bound edges and cellular metal face, the HONEY-COMB offers a new air cleaning principle to scientific filter design. Laboratory tests prove that no man-made fibre, or other non-ab sorbent surface, can equal natural hair as a medium for trapping and holding dust--with a minimum resistance to air flow. The Famous WILSON ,EDGESEAL Wilson EDGESEAL filters whip that old " problem, marginal leakage. By spring ing to fit, due to highly processed ammal hair, scientifically bound, EDGE- : SEAL adds an extra 20 per cent of face filtering area. Even greater is the addi tion toholdingcapacity. This filter works perfectly in the home. Filter banks de manding maximum area, ,a complete seal, and top efficiency should always use EDGESEAL. This advanced filter . reaches you ready to install for your greatest satisfaction and protection. ENGINEERING DATA WILSON HONEYCOMB WILSON EDGESEAL Filter Opening Size Rated Capac ity C.F.M. at 300 F.P.M. ACTUAL DIMENSIONS Width Length Thickness ACTUAL DIMENSIONS Width Length Thickness 20*x!0*x2* 200 10* 10* 2* 10H' VM' 2* 10* z 20* x 2* 400 w 2* 10H# 20H* 2* 16*x20fx2* 600 14W 19M* 2* 15H' 20H* -2* 16* *20* i 2* 640 15H* 19M' 2* 16H* 20H' 2* Ifi*x25*x2* 800 155*' 24M* 2* 16H* 25H* 2* 20* x 20**2* 800 19H' 1M* 2* 20M' 20H* 2* 20* x 2ft* x 2* 1000 mm* 24H' 2* 20H' 25H' 2* 20*x30*x2* 1200 w 29H# 2* 20M* 30W* 2* WILSON HAIR FI LTERS are manufactured in all regular and special sizes in 1 in. and 2 in. thicknesses. - (M in and H in. thickness provided when required.) 1288 Air System Equipment cSsSiSlm Baltimore Aircoil Company, Inc. 2615 Mathews Street Baltimore 18, Maryland Manufacturers of Evaporative Condensers and Cooling Towers B.A.C. Evaporative Condensers and Cooling Towers are rigidly built throughout for long, trouble-free service. Casings are of galvanized construction, providing full protection against corrosion. Sump pans are hot dipped galvanized after fabri cation. Condensing coils are prime surface steel pipe, hot dipped galvanized after fabrication. Non-metallic cooling tower surface is designed for efficient operation. Model "P" Evaporative Condenser: Vertical propeller fan type. . .outdoor installation only. . .Freon or Ammonia. Capacities: up to 100 TR. Model "P" Model "PT" Cooling Tower: Vertical propeller fan type. . .outdoor installa tion only. Capacities: up to 100 TR. Model "U" Evaporative Condenser: Centrifugal fan type. . .indoor or out door installation. . .Freon or Ammonia. Capacities: up to 100 TR. Model "PT" . Model " V " Model "UT" Cooling Tower: Centrifu gal fan type. . .indoor or outdoor in stallation. Capacities: up to 100 TR. Model "UL" Evaporative Condenser: Centrifugal fan type. . .indoor or out door installation. . .Freon or Ammonia. Capacities: 105 to 260 TR. Modd "UT" Model "UL" Model "LT" Cooling Tower: Centrifu gal fan type. . .indoor or outdoor in stallation. Capacities: 115 to 225 TR. 1289 Model "IT" $'! mt fei-" ..:< Air System Equipment ^s7 Rinks Manufacturing Co. Air System Equipment Manufacturing Company Binks non-clogging Rotojet spray nozzles Non-clogging Rotojet nozzles are the heart of every Binks water cooling system. 3130-36 Carroll Ave., Chicago 12, 111. They account largely for the efficiency and satisfactory operation of Binks water cooling installations. In addition to cooling tower applications, Binks Rotojet Representatives in all principal cities nozzles have found a wide number of uses in brine-spray and quick-freeze refrigerat ing systems, air washing equipment, metal cleaning and treating machines, chemical plants, etc. Rotojets produce a uniformly fine fluid breakup in a hollow cone pat Water cooling systems and nozzles ... a size and type for every purpose^ tern. Standard small and medium Rotojet nozzles are machined from brass bar stock, but can be made on special order from monel, Btainless steel, or other machin Binks atmospheric spray cooling towers able 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 Small sizes, in a variety of standard units threads and orifices. These nozzles may be cast in other metals for special purposes. with capacities ranging from 10 to 125 gpm--larger units handle from 600 to 1200 gpm. Special designs furnished in sizes of exceptionally large capacity. Standard tower capacity and tempera ture performance are based on nozzle pressure of 7 lbs per sq in. Ask for Bulletin 32. Atmospheric cooling towers. Type "S" |- Binks small and medium capacity Rotojet nozzles To fit l/i to % in. pipe connections. Regularly supplied in brass, with male or female threads, as specified. Discharge orifices are available over a considerable range for each size. Roto jet nozzles of this type are designed on the side inlet whirl chamber principle, which produces a fine fluid breakup and a uniform spray pattern. Binks horizontal induced draft cooling towers Binks heavy-duty Rotojet nozzles rri The horizontal draft principle of opera tion results in a tower having relatively low height. Single fan units of the spray filled type have fans from 18 to 30 in. in diameter. Larger twin units have fans from 42 to 48 in. in dimneter. Fre To fit 1 to in. pipe connections. Female threads only. Discharge orifices available in various sizes, from % in. to 1% in. The totally unobstructed involute type of whirl chamber produces a uniformly fine water breakup at low pres sures (5 to 7 lbs). . quently installed in multiples for large capacities. Ask for Bulletin $4- induced draft towers, Type "S-D" Binks Spra-Rite nozzles Produce a solid mass cone spray pattern. Small sizes for to Binks spray filled forced draft towers % in. connections are widely used for air washing, cooling, brine Small, compact, quiet, specially suitable for use with packaged air conditioners. refrigeration, rapid evaporation processes, filtering systems, chemicals, etc. Nineteen sizes for systems ranging from 3 to 21 tons of refrigeration. Binks large capacity Spra-Rite nozzles Ask for Bulletin 35. To fit 1 to 3 in. connections meet a variety of heavy-duty uses Binks blower type induced draft cooling towers in blast furnace gas washers, vibrating and revolving screen coal and gravel washers and water cooling. The squirrel cage blower provides ex tremely quiet operation. Available in single or multiple types, capacity range from 3 to 300 gpm of cooling water. Ask for Bulletins JftA and 47B. Binks steel cased Induced draft cooling towers Blower type towers. Type utBB" Binks pneumatic atomizing nozzles Series 50 nozzles are designed for use wherever conditions of controlled humidity must be maintained, as in the storage of perishable products, paper storage and printing plants, textile mills, greenhouses, etc. Nozzles of all brass construction <jeiiyer round or flat spray and are designed for use with auto matic siphon or pressure feed installations. 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 Bulletins 36 and 37. Binks induced draft masonry cooling towers Engineered for large scale air condition ing systems in towers that harmonize with the architectural features of the building. Spray or deck filled. Ask for Bulletin 88. Induced draft towers. Types "B-K-S", "B-K-li Induced draft towers w& masonry vt#1 Free technical bulletin and engineering service. Binks 40-page Bulletin No. 5200 contains a wealth of useful in- flit!rt'10n *0r.anyone specifying spray nozzles for air Con or si n-?^'/e^S6ration, humidifying, heating and ventilating, oti milar heat transfer processes. Nozzles shown above and all given 1 S8 *D Jine are illustrated and described. Data Cut-au*110 ** 6 n*ozz*e dimensions, capacities and spray angles. '`BhiP ay- drawings explain nozzle operation in many cases, ine nnJ>nnV drawings show installation details for heat- frr Q r coo*lng uses where this information is required. Write or a free copy without obligation. svftpm3 n6*ne.erin& service in planning and installing cooling heating 18 available without obligation or.cost to architects, g and ventilating engineers and builders. 1290 1291 Air System Equipment Cooling Town. The Fluor Corporation, Ltd. , 9500 South Atlantic Elvd. k< sure WITH FLUOR - Los Angeles 22, California ' E we WITH FLUOR , District Offices New York Chicago * Los Angeles - Houston - San Francisco - Tulsa - Philadelphia -- Representatives Farrell and Jones, Boston P. C. McKenzie Co., Inc., Pittsburgh - Joseph W. Rshplmwn Qq Birmingham - Bradbury-Kendrick, Detroit . '' '. Foreign Fluor Corp. of Canada, Ltd., Toronto - Head Wrightson Processes, Ltd., London - Fluor Peruana, S. A., Lima Counterflo Mechanical Draft Cooling Towera--Aerator Natural Draft Cooling Towers Thirty years of intensive development work in research, design, fabrication and erection of cooling towers enable Fluor to offer both natural draft and mechani cal draft cooling towers with guaranteed fierformance, quality construction, and ong-life service. COUNTERFLO MECHANICAL DRAFT COOLING TOWERS DESIGN: Counter-flow principle of de sign which enables the greatest possible utilization of available driving force for cooling. Available in a variety of distri bution systems, tower heights, and ar rangements. Exterior appearance de signed to complement modern plants and buildings. . PERFORMANCE. Efficient counter-flow principle provides economy cooling for all 1 services. Costs studies made on individual design conditions dictate the type of tower to be offered from' the many available designs. Performance to customer's specifications is guaranteed in every case. MAINTENANCE: Decking withstands repeated washing and cleaning and the abuse of removing and replacing. Enclosed distribution system eliminates algae growth. Stainless steel fan blades support a man's weight at their tips. Heavy-duty, precision gear units are designed specifically for the conditions peculiar to cooling tower operation. . MANUFACTURE: Completely prefabricated. Tower structure based on 4 in. x 4 in members with fan and gear supported on structural beams. Two-inch redwood in fan deck and stack. Internal.gusset plate and bolt-type structural joints take bow tension and compression loads. Over 250 tower sizes and combinations are furnished from only 258 prefabricated parts to enable fast delivery and erection. AERATOR NATURAL DRAFT COOLING TOWERS DESIGN: Fluor Aerator Cooling Towers feature two distinct design advantages: (1) A patented Aerator panel which re duces drift loss to a minimum; (2) a patented bowed deck design for structural stability and greater water distribution- PERFORMANCE: Trouble-free in operation. Cold water tem peratures in the neighborhood of 15 deg above the wet-buio temperature present a normal cooling requirement. Perform ance to customer's temperature requirements is guaranteed. MAINTENANCE: Designed for extremely low maintenance* Decks withstand severe and repeated washing. Closed distribu tion system retards algae growth. With proper treatment life expectancy is from ** to 25 years. . MANUFACTURE: Completely prefabricated. Internal gusset plate structural joints meet the most rigid building code requirements. Structure is of select redwood. - 1292 BRgwgjHK! 1 Air System Equipment cooling Towers . Foster Wheeler Corporation 165 Broadway, New York 6, N. Y. Atlanta Boston Chicago Cleveland Dallas Detroit Houston Kansas Crrr, Mo. Los Angeles Philadelphia Pittsburgh Rochester San Francisco Washington, D. C. COOLING TOWERS Guaranteed Performance . . . Custom engineered to your requirements. Foster Wheeler mechanical - draft counter-flow type cooling towers are cus tom engineered from standardized parts to meet your individual needs for service j1? ?ny location, under any climatic con ditions. ` Structure, mechanical equipment and tower filling are selected to meet the most exacting requirements in chemical plants, pubhc utilities, oil refineries, and air- Cj j10n*ng service for office buildings and department stores--year-round or intermittent operation. Features of Foster Wheeler Cooling Towers: . Uniform air and water distribution over the entire ground area. Maximum water surface exposed to the counter-flowing air. Minimum spray loss. Corrosion-resistant hardware. Easily removable non-sagging fill and drift eliminators. Proper air inlet louver arrangement to retard the formation of ice during freez ing weather conditions. 1293 Air System Equipment Ifjjjjjt Halstead & Mitchell Bessemer Bldg., Pittsburgh 22, Pa. Plant: Zelienople, Pa. One of the world's largest manufacturers of CLEANABLE, WATER-COOLED CONDENSORS COOLINQ TOWERS 20-YEAR GUARANTEE ON THE WETTED DECK SURFACE Halstead & Mitchell's use of Koppers pressure-treated wetted deck surface ex clusively, makes possible a 20-year guar antee against rotting--and provides an effective deterrent against fungi growth. MOTOR: Special weatherproofed and splashproof--for all weather conditions. SPECIAL NOTE: All towers deliver 300 cfm of air per ton @26 in. static pressure. A Cooling Tower for all applications-- from 2 to 100-ton capacities--all to strict Halstead & Mitchell "Built Like a Battleship" specifications. HOUSING: Sheet steel, electrical welded, with coatings of Vinsynite, Vinyl Zinc and chlorinated rubber. WATER DISTRIBUTION: Efficient gravity-type distributing pan eliminates extra pumping head, cuts down windage losses due to atomizing of water. DRIVE--STAINLESS STEEL Shaft: Ball-bearing grease-sealed fan bearings with grease fitting brought to outside of cabinets. Cast iron bearing supports. Adjustable belt tension. FANS: Quiet - operating, high - pressure, STAINLESS STEEL, multi-bladed. COMPLETE ASSEMBLY: All bolts used are Everdur for ease of disassembly after years of service. Easily accessible for cleaning through inlet on back of tower. | W idth Fan Dio. Cooling Tower No. WT2U WT314 WT514 WT714 WT1014 WT1514 WT2014 WT2514 WT3014 WT4014 WT5014 11? gtfC z 2 3 5 ,75* 10 15 20 25 30 40 50 Dimension (Inches) Pipes Sizes Length Height In Out Over Flow 33>* 37 435* 43>* 61 755* 76 76 100 101 125 24- 345* IKF 15*F 24 345* 15* K K*K 29 425* 154 m 29 58 2 2 29 58 2 2 29 63 2 2 44 76 3 44 76 3 44 76 3 72 76 4 72 76 4 1 1 1 1x IH 15* \X IX IX 2 2 Motor Air Inlet HP RPM Ht X Width 16 100C 16 1000 24 X J725 24 X 1725 24 1725 24 X 1725 36 36 XQ. 1725 1725 36 1 1725 42 1 1725 42 15* 1725 224 X 21)4 224 X 214 28H X 264 444 X 264 444 X 264 484 X 264 55 X 40 55 X 40 55 X 40 55 X 68 55___X 68 198 210 380 495 665 855 1440 1600 1920 280C 3160 303 345 755 890 1200 1495 2370 2550 3U0 4800 561C Also available in 75 and 100 ton sizes. Open Type Distribution Pan. Capacity 78 deg. Wet Bulb .. In larger towers, open-type pan allows bringing inlet water through the center, providing better distribution over entire pan. ` Remote water basins may be had for basement installation for year around operation even during freeiinf weather. . Send for complete Descriptive Bulletins on Cooling Towers and Condensers. 1294 Air System Equipment cooling Towers Lilie-Hoffmann Cooling Towers, Inc. Exclusive Builders of Cooling Towers for SS Years 4239 Duncan Ave., St. Louis 10, Mo. Two Modern Plants--St. Louis, Mo., and Plainview, Texas INDUCED DRAFT TOWERS New type filling reduces static pressure. Filling consists of slats, assembled in grids. Slat arrangement insures maximum wetted surface, minimum pressure drop of air .flowing through tower packing, and uniform distribution of water and air over the entire effective area within the tower. Gravity distribution system requires only one riser pipe. Teco timber connectors develop 100 per cent working stress of members. Normally constructed of selected California redwood. All fans furnished by LilieHoffmann are P.F.M.A. tested and certified. ATMOSPHERIC SPRAY TYPE Generally offered in capacities up to 3000 gpm. Distribution by galvanized pipe header with smaller lateral arms, equipped with non-clogging spray noz zles. Water atomized as finely as possi ble. . Sides and ends of towers equipped with narrow louvres, which fit into mast slots--no nails required. Recommended where cost is prime factor; and close approach to wet bulb is unnecessary. horizontal draft package Type) Resigned .specifically for 4 lo 60 ton [^ngeration installations. Struct ure and )as,n of California Redwood. Sides of orrugated and fiat cement asbestos ? sets with stainless steel trim; no paint- required. Distribution of splash grav^Pe, non-sag, non-warp removable 1295 / ' Air System Equipment cooUntTm^T The Marley Company rr. uoi_c,^__uni:}*,-rnr ac iiofto vujf mioovuu Representatives In AH Principal Cities (Consult Classified Pbone Directory) .Water Cooling Towers and DrlCoolers of All Types and Capacities. Spray Nozzles MARLEY DOUBLE-FLOW AQUATOWER ... The new 'low silhouette," low pumping head tower for air conditioning and refrigeration jobs of 60 tons or more--a 150-ton model is only feet high. This entirely new tower provides Double-Flow efficiency combined with Aquatower simplicity. Produced in a wide range of standard sizes of all steel or wood with asbes tos cement board casing, it has open distribution, full height louvered sides, and all fittings and mechanical equipment are completely accessible. Write for Bulletin DFA-54- MARLEY Aquatower... For "packaged" cool water, the steel Aquatower packs solid performance for even the extra tough jobs. Aquatowers are available in ten sizes ranging from 3 to 60 tons of refrigeration. Thousands of Aquatowers have proved themselves in years of maintenance-free performance. They are carried in stock, shipped completely assembled and require no field erection. "Large models may be readily disas sembled to facilitate handling. Write for Bulletin AQ-54- MARLEY Redwood Forced Draft Aquatower . . . this cooling tower is produced in three models, serving air conditioning or refrigeration in 5-, 7J^-, and 10-ton capacities. It utilizes the forced-draft, cross-flow, vertical discharge principle. De signed especially for localities with high corrosion incidence, the forced draft design permits location of mechanical equip ment out of the hot, humid air stream. Rugged, all-boltea, all-redwood construction assures long-life durability. Ex terior of tower is finished with attractive redwood resin stain. May be installed either outdoors or indoors. Easily vented when installed indoors. Write for Bulletin RAQ-5S. MARLEY Natural Draft... These heart quality redwood tow ers are available in two series. Economical to erect and op erate, sturdy and long lasting. Assures top performance. Series 100 . . . used primarily for refrigeration and air condi tioning small buildings, thfeaters, locker plants ranging up to 35 tons of refrigeration. Series 200 ... is built in standardized units for larger capacities and is also available with atmos pheric sections for indirect cooling of jacket water, oils and gases. Write for Bulletins 100-54 or BOO-54. MARLEY Cross-Flow . .. Three types of Marley large capacity industrial cooling towers embody this unique Marley design principle . . . the Double-Flow, TwinFlow, and Single-Flow. The Double-Flow is designed for use wherever large gsllonages of water must be cooled economically and efficiently. Marley Twin-Flows are recommended for largest cooling capacity with limited tower area, and Single Flows are designed to give maximum performance in a limited plan area. Each type of tower offers many exclusive Marley Cross-Flow features and advantages: maximum air-water contact due to horizontal air flow through full height louver walls . patented Marley non-sagging, non-warping, non-cracking, nail-less fill - - - *" open water distribution system. Other advantages include low pumping head, mini mum draft loss, quick inspection and easy maintenance. . Rugged construction assures long-life durability. All mechanical equipment is Marley-designed and Marleymanufactured exclusively for cooling towers. Write for Bulletin CF-5S. 1296 Air System Equipment. cooling Towers J. F. Pritchard & Co. Dept. 320, 210 West 10th St., Kansas City 5, Mo. Chicago Houston New Yobx Pittsburgh St. Louis * Tulsa Representatives in Principal Cities from Coast to Coast - Cooling Towers Specialized Heat Exchangers Gas and Air Treating Equipment Construction and Processing Facilities COOLING TOWERS of standard Pritchard design will meet your cooling needs efficiently and economically with maximum water saving--conserving up to 99 per cent for re-use. Experienced design plus guaranteed performance ratings to meet your specific requirements assure adequate capacity and long, interference-free operation. Many patented features not available in any other towers (see below). Specifications, ratings and prices furnished promptly, without obligation. SEALDFLOW* FAN DRIVES are fully encased, self-ventilated by fresh air from outside the fan stack--no hot, saturated vapors from tower discharge can enter assembly. Completely inte grated assembly mounts motor and gears directly on the fan shaft and encloses them in one compact unit for long inter ference-free service. POWalrSAVER* FANS were especially developed by Pritchard for cooling tower service . . . designed for operation at high aero-dynamic efficiency and low horsepower. Adjustable pitch blades available in 6 ft to 20 ft diameters, in 4, 6 or 8 blade assemblies. SERIES "D" FAN THROAT is a modi fied Venturi design, fabricated in panels of all heart redwood--bolted together for rigid construction which permits close blade clearances with resultant high fan efficiencies. Contains no steel, castings, brackets, rods or.turnbuckles. * Registered Trade Name WRITE FOR SPECIFIC INFORMATION AND BULLETINS. 1297 Air System Equipment cooung Tower, Santa Fe Tank & Tower Co. Since 1903 5401 So. Boyle Ave. Los Angeles 11, Calif. Atlanta El Paso New Yore . Branch Offices Boston Chicago Dallas Houston - Minneapolis San Francisco Tulsa Denver Detroit New Orleans Washington, D. C. SANTA FE Induced Draft Cooling Towers Santa Fe Induced Draft Cooling Towers are engineered to provide the most econom ical unit per cubic foot of space required. They are designed for continuous opera tion, and standard structural design will withstand wind loads up to 100 miles per hour. Specially designed decks assure proper break-up of water and a balanced distribution of air. Either gravity or spray type distributing system. Inner and outer sheathing serves as an in sulator and prevents deterioration. Clear and select California Redwood provides a sturdy framework to with stand all live and dead loads. Me chanical equipment is selected for con tinuous operation. NEW "MD-54" This tower represents an important step toward the development of a cool ing tower with a substantially improved structural design. Simplified construc tion and better utilization of materials is the key to its improved performance. The "MD-54" requires fewer parts for construction, and thereby allows for faster erection and less maintenance. To make the "MD-54" adaptable to indi vidual requirements, two separate stand ard types of decks were designed. One is best suited to lowest first cost, and the other to the lowest evaluated cost on an amortized basis. A new bracing system is used to minimize obstruction to the free flow of air. The result is better cooling performance. This new type of bracing re quires only two specially designed joint connectors in conjunction with 3 standard braces to build any size or height of the "MD-54" cooling tower. SANTA FE Econotower (Series V) A prefabricated tower furnished with either a double Redwood shell or Red wood interior wall and Transite exterior wall. Prefabrication assures simple field erection. Available with grayity or uniform spray type distribution. Spray distribution system consists of steel pipe headers with Santa Fe bronze nozzles. Sturdy interlocking decks are made in assembled sections and can be removed. Multiple-blade, belt-driven fans are durable and corrosion resistant. Motors are NEMA standard specifica tion, either totally enclosed fan cooled or splash proof type, as specified. Red wood towers may have collecting basins manufactured from durable Redwood. These units utilize bolted construction and are furnished with a heavy galvan ized steel sump with Vortex breaker and float valve for make-up water. 1298 Air System Equipment spray Nozzles Monarch Manufacturing Works, Inc. 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 in. to 1 in. pipe sizes inclusive, and of Brass, Stainless and Monel. Capacities: Gallons per Hour Sizes . Lbs Operating Pressure Pipe Orifice Lead 69 69 61 61 61 53 53 53 49 49 % w H' H' %' w %w w Vkm 10 4.4 5.8 9.1 11.8 19.5 24.3 31.5 52.2 78.0 83.0 20 4.0 6.2 8.2 11.1 16.6 27.6 34.6 46.1 75.0 112 121 30 2.9 5.0 7.5 9.8 13.2 20.4 33.3 43.8 57.0 92.5 138 152 40 3-3 5.5 8.3 10.9 15.0 23.4 39.1 50.0 64.1 109 163 180 60 4.0 7.0 10.3 14.1 19.5 29.0 49.0 64.0 81.9 138 205 225 100 5.1 8.7 13.0 17.3 24.6 36.5 60.0 78.5 105 189 257 300 AIR CONDITIONING AND OIL BURNER NOZZLES Water Capacity in Gallons per Hour Pig. PSO Nozzle No. ' 1.35 1.65 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 6.00 7.00 25 1.03 1.36 1.56 1.86 2.20 2.22 2.55 2.90 Lb Operating Pressure 40 .57 .75 .94 1.13 1.39 1.77 2.00 2.32 2.88 2.96 3.35 3.91 GO .69 .89 1.14 1.45 1.62 2.11 2.42 2.77 3.57 3.75 4.01 4.60 80 .83 .99 1.28 1.64 1.85 2.46 2.77 3.21 4.09 4.31 4.78 5.17 100 .92 1 12 1.40 1.86 1.95 2.80 3.16 3.68 4.59 4.78 5.23 6.00 Produce finest breakup possible with direct pressure only. Capacities above are on water. "Nozzle No." is capacity on 34 second Saybolt viscosity 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 y% in. or K in. female pipe Brass adapter and Monel gauze strainer. SPRAY POND NOZZLES For recooling condenser water, etc. Operate on pressures- from 5 lb upward. Made of Cast Red Brass and in pipe sizes 1 *n-> in., 2 in., and 2J^ in. Capaci ties from 4.1 to 88 gpm at 7 lb pressure. Write for Detailed Catalogs 1299 Pig. BS Air System Equipment. KeT^Ser SurtK>P flCfllE MDUSTRIES, me. JACKSON, MICHIGAN, U.S.A. Continuously serving the air conditioning and refrigeration industry since 1919 34 years experience stands behind these ACME products Since 1919 Acme has been building units to serve the air conditioning and re frigeration field. They have experi mented with thousands of models and installations. On-the-job service has alwayB been the basing point for any Acme design changes. Today, Acme has a complete line of commercial refrigera tion and air conditioning equipment-- the end result of 34 years effort. You gain all this experience for yourself and your customer simply by specifying Acme on your installations. THE FLOW-COLD LINE The Flow-Cold is a factory assembled and tested packaged liquid chiller de signed for use in industrial process temperature control and air condition ing. Used as-a heat pump and installed with the Flow-Temp Remote Room Conditioner it provides both heating and cooling. ACME DRY-EX WATER CHILLERS For cooling water, brines, and other fluids by direct expansion of the re frigerant. Capacities from 5 to 260 tons. EVAPORATIVE CONDENSERS and COOLING TOWERS Solid, sturdy, dependable. All. fabri cated steel parts are hot-dip galvanized after fabrication assuring long life. Prime surface coils or specially designed Acme packs for Freon or Ammonia in stallation. Capacities from 4 to 130 tons. FREON and AMMONIA CONDENSERS The standard of the industry. Enough production combinations to assure you of the most efficient operation available. Capacities from 3^ to 700 tons. Write for catalogs and more Information on any ACME product. HEAT EXCHANGERS, LIQUID RECEIVERS, OIL SEPARATORS Freon suction and liquid line heat ex* changers with capacities from 3 to 200 tons; more than 70 standard sizes of liquid receivers for Freon, Ammonia or other refrigerants; and a complete line of Freon or Ammonia Oil oepa* rators for to 100 ton systems- 1300 Air System Equipment Heat Transfer Surface /lefUJFiN Corporation 410 So. Geddes Street Syracuse 1, N. Y. Aerofin Standardized Light-weight Heat Exchange Surface There is a factory-trained Aerofin application and service engineer located near yon to give you prompt service. Write, wire or phone the factory. Aerofin is the modern Standardized Light-Weight Encased Fan System Heat ing and Cooling Surface originated by. Fan Engineers to meet the present and future requirements of this highly specialized held. All Standard Aerofin Units are furnished as completely en cased Units, ready for pipe and duct connections. The patented casings are built of pressed steel and are exception ally strong and rigid, protecting the Unit from all the strains of pipe connections and expansion or contraction in service. The casings are flanged on both faces, top and bottom, and template punched for bolting together adjacent Units, or for duct connection. units or for installing in ducts. May be installed either horizontally or vertically. Used on any two-pipe steam system for preheating or reheating. Modulating control on preheaters. Available in 13 lengths and 3 widths, from net face area of 2.76 sq ft to 26.28 sq ft. # Fig. t Flexitube Aerofin (Fig. 2) is distin guished from all other developments by its off-set tubes, so arranged as to absorb all expansion and contraction strains. Headers--Steel. . Tubing--6 in. O.D. copper, admiralty or aluminum. . Joints--Where admiralty or copper tubes are used together with bronze or steel headers tubes are brazed to headers. Where both aluminum tubes and headers are used tubing is welded to headers. Casings--Copper, aluminum or galvan Aerofin Non-freeze heater (Fig. 1) is non-freeze, non-stratifying spiral fin coil UlIt into casing for air conditioning; ized iron. Design--Constructed,with headers on opposite ends making possible installa tion of units with tubes horizontal or vertical. 1301 Aerofin Corporation Air System Equipment sSiJ-" Aerofin Corporation Air System Equipment sif'aansfer Fig. S Universal Aerofin (Fig. 3) is distin guished by its "S" bend construction of tubing, units designed with steel headers on opposite ends, the ends of the "S" bends being connected thereto by com pression nuts, the bends taking care of the expansion and contraction of the tubing. Recommended where close control is desired. * Headers--Pressed steel. Tubing--1 in. O.D. copper or admi ralty. Casings--Copper, aluminum or galvan ized iron. Fig. 5 Booster Aerofin (Fig. 5)--straight tube type, single pass construction for pres sures from 1 to 200 lb gauge. Headers--steel. Tubings--% in. O.D. copper^ Casings--copper, aluminum or gal vanized iron. Recommended where small coils are needed or to raise the air temperatures in branch ducts. Fig. 6 Aerofin Heavy-Duty Industrial Heating Coil (Fig. 4) for use where extra-rugged coil is needed for close control. Steam pressures from 25 to 450 lb gauge; tem peratures to 550 F. Headers--Pressed steel. Tubing--1 in. O.D. heavy copper. Casings--12-gauge galvanized iron. Narrow Width Aerofin: (Fig. 6) recom mended for water cooling or for flooded Freon systems. Made in straight tubes only with headers on opposite ends, joint between headers and tubing being brazed. Construction similar to Flexitube Aerofin. Aerofin Continuous Tube Water Coils (Fig. 7) are designed for air cooling by circulating cold water through the Aerofin and air over extended fin surface. Made for either horizontal or vertical air flow. Tubes and fins are copper, completely tinned with permanent metallic bond between fin and tubes. Headers are made of steel and casings of heavy gal vanized iron or copper. Tested to 100 lb steam, followed by 450 lb air with coil submerged in water^ Fig. 9 Aerofin Direct Expansion Units: (Fig. 9) Centrifugal Header Type--For cooling air, using Freon expanded directly into the coil. Aerofin Sizes Flexitube: 13 standard lengths, three widths, one and two rows deep. Narrow: same as Flexitube. Universal: 17 standard lengths, two widths, one and two rows deep. Continuous Tube: 13 standard lengths, three widths, 2-3-4-5 and 6 rows deep. Cleanable Tube: 17 standard lengths, one width, 2 and 4 rows deep. Direct Expansion: Centrifugal Header --11 standard lengths, three widths, 2-3-4-5-6 rows deep. Steel Supporting Legs: 18 in. and 24 in. high. Punched same bolt hole centers as standard casings. Quickly attached. Fig. 8 Aerofin Cleanable Tube Units (Fig. 8) 0r cooling only made with headers re movable to permit cleaning tubes. No other foundation required. Sale: Aerofin is sold only by manu facturers of nationally advertised Fan System Apparatus. List upon request. ecommended for use where sediment or e forming chemicals are present in the cooling water. Headers--Fabricated steel. Tubing--Copper or admiralty. usings Copper or galvanized iron. Write Syracuse for Heating Bulletin H-45; Direct Expansion Bulletin DE-48-1 on refrigeration type units; Continuous Tube Bulletin C.T. 39-2 for Water Cool ing coils; or pamphlet on Cleanable Type Aerofin for cooling. 1303 Air System Equipment ?dtn3?nsla Edwards Engineering Corporation 101 Alexander Ave., Pompton Plains, N. J. Mfrs. of Finned Heat Transfer Tubing for Baseboard Radiators and Convectors, Freon Condensers & Evaporators, Heating & Cooling Coils. FINNED FREON CONDENSER TUBING AND COILS This finned tubing was especially designed for the condensa tion of freon refrigerants. This optimum tube design consisted of % in. high copper fins spaced 12 to the inch. Tube sizes were selected to permit the design of continuous tube double cir cuited condensers for packaged air conditioning units of 2, 3, 5 and 7^ ton capacity. The double circuit permits the use of series circuiting for city water and parallel circuiting for cool ing tower applications. The dead soft tubing may be bent by means of special bending jigs into a variety of compact shapes, (see illustration) by Edwards Engineering Corp., making a compact package for shipment. Also available as highly eco nomical water-saving water chillers. FINNED TUBE WATER HEATERS Edwards finned tube water heaters are fabricated from finned tubing specifically designed for tankless water heating serv ice. The tube and fin are both copper. The % in. high fins are helically wound about the tube and. are spaced 12 fins per inch. The fins are bonded to the tube with virgin solder-- consisting of 30 per cent tin 70 per cent lead. This construc tion has high capacity per lineal foot combined with ease of workability and low cost. Every conceivable shape and con figuration is available. (See illustrations) We suggest that the boiler manufacturer pick a shape that will fit his requirements most closely, then write us for specific dimensions. Tests have shown us that with our tubing, there is little difference in performance between the various shapes. This water heater tubing is ideal for heating liquids by means of steam passed through the tubing. Therefore, these water heaters make excellent steam heating coils for water, oil, organic solvents, and a variety of chemical solutions. Although other types of our finned tubing are more efficient for heating air or gases with steam, these standard tankless heater coils are available and have proved themselves for this purpose. Straight lengths of finned tubing are available to coil manufacturers for fabricating apartment house heaters or to chemical plants for making heat interchangers. SPIRAL-FIN RADIATION Designed specifically for industrial and commercial applications. Fabricated from standard steel pipe (1 J4 in. or 2 in.) with 3)4 in.-4)4 in.-4)<J in. or 5 in. diameter, spirally wound fins. Faster heat trans fer, ease of installation, ruggedness and economy are inherent in the design. Can be installed in one, two or three tiers, with suitable solid or expanded metal covers. SPI-ROL-FXN baseboard radiation (spirally wound aluminum fins on copper tube) is available for efficient, economi cal residential heating. Complete with cover and accessories. WRITE FOR CATALOGS, LITERATURE OR INFORMATION. 1304 ' Air System Equipment sSfacensfer The G & O Manufacturing Company 138 Winchester Avenue New Haven 8, Connecticut INDIVIDUAL 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 radia tion, and convector elements. A--Generous Fin Collar provides large contact area between Tube and Fin- B--Tube expanded against Fin Collar; insures mechanically tight joint made permanent by bond of high ^emperature alloy--complete ther mal contact. C Free air-flow passages; non-clogging. STANDARD SIZES O.D. of Tube Fin Sue Fin Spac Surface per ing per Inch Linear Foot w ?A* sq. 6 0.80 sq. ft. w W r'd. 6 0.60 sq. ft. O' m* X V oblong & 'US'r'd. 6 3.65 sq. ft. 6 0.87 sq. ft. 54' . 1 \ r'd. 6 1.55 sq. ft. 54' 1' lit' lA" sq. 2}im sq. 2#' sq. 254* sq. 6 2.40 sq. ft. 6 4.15.sq. ft. 6 4.00 sq. ft. 6 3.82 sq. ft. r'd. 4 2.33 sq. ft. RADIATING elements for a G&O Finned Radiation Coils for indu range of sizes.1 . HEAT TRANSFER PURPOSES ial applications are available in a wide Universal Type B Standard No. 10 Send for Catalog and Price List 1305 / . Air .Ctre/^rn Rtririfimonl Moore DotIjgif Company 1220 W. State St. Jacksonville, Fla. Plants also at: North Portland, Ore.--Brampton, Ont.--Vancouver, B. C. MOORE-FIN RADIATION (Steel Piping) Air System Equipment Heat Transfer Products The Patterson-Kelley Company, Inc. 101 Burson Street East Stroudsburg, Pa. New York 17 . 101 Park Avenue Philadelphia 3 1700 Walnut Street Boston 16 . 96A Huntington Avenue Chicago 4 Railway Exchange Building Representatives in Principal Cities P* Heat Exchangers for Heating, Air Conditioning and Refrigeration Service. Hot Water Storage Heaters--Instantaneous Heaters--Convertors--Fuel Oil Heaters --Freon Coolers--Condensers--Balance Loaders--Interchangers--Suction Line Ex changers--Slug Eliminators--Coolers for Water, Brine and other Liquids. Since 1880, |-c has designed, engineered and fabricated heat transfer equipment to meet industries' most exacting requirements. We are prepared to recommend and design exchangers for air conditioning, refrigeration, process and industrial cooling applications. . I'l* Preon is. Pin Tube Condenser. APPLICATIONS: Factory Heating Systems; Greenhouse Heating Systems; Base board Radiation; Steam and Hot Water Coils; Blast or Booster Coils; Heat Ex changers; Refrigeration Coils. Sizes and Ratings on Moore-Fin Radiation Pipe Diameter* Overall Diameter (including fins) Heating Surface (per lineal foot) Weight (per lineal foot) 1' 2`Me' 2.8 sq ft 5.25 lbs l.K' ZW 3.25 sq ft 6.38 lbs l.W' 3W 3.5 sq ft 7.1 lbs PIPE: Heavy steel wall type for pressures up to 150 lbs per sq in. LENGTHS: Furnished cut to length. Maximum single length. 20 ft. END CONNECTIONS: Threaded American standard pipe with right hand threads, or chamfered for weld. . Also available.in following sizes: H in., 2J4 in., 3 in. and 4 in. Moore-Fin Radiation--a steel finned pipe-- is suited for many different heating and cooling applications. It may be the answer to your problem. Write for information. , 1306 I*-**. Freon Cooler (Dry Expansion Type) 2-circuit construction. All He Coolers built in accordance with the ASME 6ode, Par. U-69, for unfired pressure vessels. Freon Cooler (Dry Expansion Type) -circuit constructioD for 200-too refrig eration capacity. Catalog number 101 contains tables, . charts and complete data which will en able you to select the Cooler which exactly meets your needs. 1307 Air System Equipment The Rittling Corp Executive offices: Rand Building Buffalo 3, N. Y. Factories in Hamburg, N. Y. and Brooklyn, N. Y. Manufacturers of Finned Tube Surfaces, ; * Baseboard Heating, Unit Heaters, . \ Finned Tube Convector Radiators, 5 Cabinet Type Convectors, Back Draft - I Dampers {' Factory Representatives in ail Principal Cities : | (Consult Classified Telephone Directory). Fat { complete descriptions and specifications, send di- ; rect to executive office for catalogs on all items. . BASEBOARD HEATING Heating element; in- copper tube with 2 x 3 in. steel fins. Covers: heavy steel. Hot water rating: 485 Btu at 180 deg. High capacity element also avail able: two Yi in. copper tubes with 2 x 5^ in. steel fins. Hot water rating: 680 Btu at 180 deg. Easy installation. See Sketches. p"3^TM TM8 Hang Healing Element f Air System Equipment Fin Tubing and Colls The Rome-Turney Radiator Company Erie Boulevard, East Rome, N. Y. ' I ROME H | TURNEY RADIATOR COMPART Manufacturers of "Ro-Fin" Tubes for Efficient Heat Transfer - In Philadelphia seb W. H. Buntkn, 1205 Hamilton St. In St. Louis see Bbabs and Cofpeb Sales Co., 2817 Euclid Ave. In Buffalo see J. Landebs, 170 Franklin St. "RO-FIN" Extended Surface Helical Fin Tubing for Heat Transfer __________ FINNED TUBE ' CONVECTOR RADIATORS , Snap-on cover and accessories f in. copper tube with 3 in. square aluminum fins, rated 4.25 sq ft EDR per lines ft. in. IPS steel tube with 3 in. square steel fins, rated 4.25 sq ft EDR per lineal ft. 1^2 in. IPS steel tube with 4 in. square steel fins rated 5.91 sq ft EDR. 2 in. IHj steel tube with 4 in. square steel fins, rated 5.25 sq ft EDR. Plain front, louvreo openings, fiat or sloping tops. Baseboard type enclosures, fully enclosed or opefl inlet also furnished for all types of finned tube. * i } s CABINET CONVECTORS: Six cabinet styles available with ratings from 7 to sq ft EDR. Copper tube, copper headers, aluminum fin elements. # . BACK DRAFT DAMPERS: For high or low velocity. Positive action, positive sea1* Extremely sensitive, light weight non-metallic blades. UNIT HEATERS: Horizontal or vertical. Steam or hot water. Sizes range fro h*' EDR to 2,000 EDR. 1308 i 100 Sizes in Production: Outside Tube Diameters: % in. to l-% >nFin Widths: % in. to % in. No. Fins per Inch: 3 to 19 "RO-FIN" TUBES can be furnished in continuous lengths, with or without joints. Straight lengths up to 25 ft long. ---- -UUA LDUMinO COILS U-BENDS - furnished with or without threaded end connection, or for standard flare connecRO-FIN" TUBES are adaptable for all types of heat transfer work, and are ma e individual specifications of each order./' Write for Information on Heat Transfer "roblems involving: Refrigeration Condensers Fluid Recovery Condensers Concealed Radiation Convectors ` Steam Condensers Fan-Type Unit Heaters Diesel Engine Cooling Baseboard Radiation **RO-FIN" T UBES shown in convector radiator for heating homes, offices, churches, schools. 1309 Air System Equipment. The Vulcan Radiator Company 26 Francis Avenue ^- " Representatives in Principal Cities Hartford 6, Conn. Vulcan Radiation (Linovector) is used in rairoad cars, ships, hospitals, schools, churches, homes and industrial plants. Available in steel or copper . . . easy to install . . . light in weight . . . requires few fittings and supports . . . tube ends threaded or chamfered for welding.. Heat distribution is uniform. Steel ra diation comes in two sizes ... 2 in. IPS, rated--5J sq ft per lineal ft at 1 lb steam and 65 deg air . . . for lj in. IPS see illustration--this size also available . in copper. Illustrated catalog available. Standard Linovector Covers Grille Type F Type S Cover _ I=>B =R Ratings for Vulcan Linovector. available in , catalog 6i5A. Vulcan Radiation is fabricated by mechanically imbedding offset fins or plates on seamless steel pressure tube or copper water tube. The patented offset fin construc tion gives complete rigidity to the entire assembly and extends the heating surface of the tube. . Because of its comparatively light weight and compactness, Vulcan. Radiation re sponds quickly to thermostatic control. Full heat output is obtained almostttmmedi- ately after steam is supplied. Since most of the heat is given off bv convection, the result is EVEN, UNIFORM HEAT from floor to ceiling. . Vulcan Baseboard Radiation . .. fin-on- tube construction with TRIMLINE cov ers combines radiant and convection heating. High safe working pressure . . . either hot water or two-pipe steam systems. Light in weight . . . easy to install . . . requires few fittings or sup ports. Comes in two sizes ... 1 in. IPS . . . steel fins 2\ in. wide by 3i in. high and 1 in. IPS, 2 in. x in-----for 1 <n IPS, see illustration. Also available in copper. / in. IPS TRIMLINE covers in continuous lengths up to 15 ft. Built of JJSi-gage galvanite steel l*BsR ratings for Vulcan Radi- Vector available in Catalog No. 54. 1310 Illustrated catalog available. Air System Equipment Refrigerating Machinery Brunner Manufacturing Company Dept. M-54, Utica, New York, U. S. A. Refrigeration Air Conditioning Air Compressors Industrial Gas Compressors PRODUCTS: Refrigeration compressors and condensing units for commercial and industrial use--motor-compressor units for use with evaporative condensers, 2-stage and sub-zero units, truck units, self-contained and remote air conditioning, industrial liquid chillers. Also complete line of single and two-stage air compressors for pneumatic control and other industrial applications. Industrial Gas Compressors for transferring Liquefied Petroleum Gas, Anhydrous Ammonia and booster for nat ural gas in manufacturing plants. Refrigeration Compressors Complete line of 2, 4 and 8 cylinder re frigeration compressors, adaptable to any need. Designed for slow-speed opera tion, less wear, longer life. F-12andF-22. Air and Air-and-Water Cooled Condensing Units 34 hp to 3 hp, for" Freon-12" refrigerant, finned tube condenser. Also-34 bp to 3 hp combination.air and water cooled units, with cleanable condensers, to.handle fluctuating loads. Water Cooled Condensing Units K hp to 75 hp, for every commercial and industrial use. "Freon-12" or "Freon22 refrigerants, with cleanable con densers. Air Compressors Complete line--single stage from 34 hp to 2 hp, two stage from 134 bp to 40 hp. Air compressors 5 hp and over available with water-cooled after-cooler. Industrial Refrigeration oizes up to 75 hp, complete line of water- cooled condensing units and compressor units for use with evaporative condens- er8 for industrial refrigeration and air conditioning use. Capacity controls available. * Air Conditioning Units . : 2, 3, 5, 7}, 10, 15 and 20 hp sizes, com pletely self-contained, in various styles for commercial and residential use. Easily installed. Liquid Chiller-Ice Builder Highly efficient liquid chilling cabinet and ice builder. Models from 34 bp to 734 hp factory-assembled--larger models as required. . 1311 Air System Equipment Curtis Refrigerating Machine Division of Curtis Manufacturing Company 1959 Kienlen Ave., St. Louis 20, Mo., U. S. A Established 1854 New Yobk Office 30 Veset St. . Chicago Office 9 S. Clinton St. Full Line of Units from to 40-hp. Unit Coolers, Air Handling Units, Evaporative Condensers, and Cooling Towers PRODUCTS: Complete Refrigerating Equipment for Dairies, Creameries, Ice Cream - Cabinets, Ice Cream Making Plants, Cold Storage Locker Systems, Walk-in Coolers, Drinking Water Systems, Commercial and Low Temperature Cooling, Processing and Air Conditioning Installation, Packed and Remote Types. Combination air and water cooled Condensing - Units. H Through 2 hp. VAhp Air Coded Condensing Unit. Other its from M to S hp. IS hp Cleanable Shell and Tube Condensing Unit. Other Sizes from to 40 hp. Year-round Cool ing and Heating Unit--8 and S tons Commercial Refrigeration Air cooled condensing units from to 3 hp, inclusive, com bination air and water cooled units from to 3 hp, inclusive, and water cooled units from },$ to 40 hp, inclusive. All models charged with Freon 12 refrigerant. Mechanical advantages in clude Timken Bearings, Positive Pressure lubrication. . Special models are available for ice cream, frozen food cabinets and for the dairy industry. l,3,S,7H ani 10 ton Packaged Type Air Conditioner. ' 10-15 ton Remote or Central Type Air Conditioner. Atlanta Boston Buffalo Charlotte Chicago Cincinnati Dallas Kansas City Los Angeles Air System Equipment Frick Company Air Conditioning, Refrigerating, Ice Making and Food Freezing Equipment Waynesboro, Penna. Distributors in true maox Principal Cities Memphis New Orleans New Yobs Oklahoma City Palatsa Philadelphia Pittsburgh St. Louis Seattle Washington AIR CONDITIONING Complete Frick Systems; also refrig eration for use with equipment supplied by others. Thousands of installations attest the value of Frick air conditioning. Successful experience with exacting com mercial and industrial jobs since 1910 enables us to solve your problems. Frick "ECLIPSE" FREON-12 REFRIGERATION Compressors. Bulletin 100. Frick low-pressure units, "ECLIPSE" machines, and the larger enclosed F-12 compressors provide a complete and ef ficient line. Air conditioners, coils, coolers, condensers and controls to suit. Patented Flexo-Seal at shaft, pressure lubrication from reversible pump, capac ity controls, and other unique features make Frick machines your logical choice. See Prick Bulletin 602 on air conditioning for hos pitals, SOS on ammonia systems, S04 on typical installations, SOS on en gineering details, and 622 on unit conditioners (il lustrated). Combined Unit with "ECLIPSE'* Com pressors. Bulletin 100 AMMONIA REFRIGERATION Combined units and vertical enclosed compressors, with two or four cylinders, in sizes from 2J^ tons up. Also "ECLIPSE" conmressore for ammonia, with 3, 6, or 9 cylinders. Widely used for air conditioning, with material savings. Ask for Bulletins 100 and 508. ' Enclosed Ammonia Compressors. Bulletin 112. Air Conditioning For today's Air Conditioning requirements Curtis offers com plete packaged, refrigerated air conditioning units, requiring only water and electrical connections to install. Cools, dehumidifies, circulates and filters the air. Eliminates costly installation expenseAdaptable for heating. ' 1312 _Two Frick fiM * 5H "ECLIPSE" Compressors air conditioning an office building. Driven by 800 hp, 1200 rpm motor mounted between them. 1313 Air System Equipment 5SdK2?" Mario Coil Co. G135 Manchester Ave., St. Louis 10, Mo. Manufacturers MARLO = MEAn-_ Sine. (925 IRANSFER Equipment Industrial Coolers--Unit Coolers--Evaporative Condensers--Low Temperature Units-- Air Conditioning Units--Heating and Cooling Coils--Cooling Towers--Diesel Engine and Oil Evaporative Coolers.__________________ _________ ________ COOLING TOWERS--industrial and commercial--20-100 tons--induced draft; wetted deck surface, water spray--out door-indoor. "THRIFTI-TOWER"-- smaller adaptation for residential, light commercial use--2-16 tons. Write for Bulletins 406, 406-A. ' . CEILING TYPE AIR CONDITIONING UNITS--cooling, heating, dehumidifying^ humidifying. 14 sizes--1 to 150 tons --640 to 37,200 cfm. Ceiling suspended, floor types. Write for Bulletins 408, 409-MZ. INDUSTRIAL COOLERS--15 unit sizes --1,000 to 26,400 cfm--blow-through and pull-through type. Write'for Bulletins 392,412, 40S. (. REMOTE ROOM AIR CONDITIONING UNITS--permit individual climate selec tion. No ductwork, only simple piping needed. Floor and ceiling type units. Write for Bulletin 1149. . ' . BLAST COILS--air conditioning, indus trial- refrigeration, heating. Any mate rial-all refrigerants--every application. Pressure-expanded staggered tubes, con tinuous plate-type fins. Write for Bulle tins 396-A, 495. / MULTI-ZONE UNIT--complete winter and summer functions--individual zone control--1,500 to 17,000 cfm. Write fr Bulletin 409-MZ. ' Ceiling Type Air Conditioners^ Air System Equipment Refrigerating Machinery Gas and On Atlanta Boston Chicago The Ready-Power Co. 11231 Freud Ave., Detroit 14, Mich. Cincinnati Dallas Detroit District Offices or Representatives Philadelphia Pittsburgh Los Angeles Milwaukee New Orleans New Yobk AEflDV-POUlER Seattle St. Louts Washington AIR CONDITIONING AND REFRIGERATION EQUIPMENT SAVES AS IT SERVES Manufacturers of Gas and Diesel Engine Driven Generators arid Air Conditioning Units; Gas and Diesel Electric Power Units for Industrial Trucks. Ready-Power Engine Driven Com pressor Units are designed and built to rnget the need of (1) Low operating cost air conditioning and refrigeration em ploying N ATURAL GAS fuel and (2) Air Conditioning and refrigeration where Electric power is not available or high in cost. It is particularly adaptable to . portable equipment for cooling airplanes, before take-orf, for pre-cooling perishable food shipments by rail or truck, and for installations in refrigerated rail cars and trucks. CAPACITY MODULATION The Ready-Power inherent system of capacity modulation permits operation ` the compressor to meet the needs of frying conditions. This assures much etter control of temperature and urnidity conditions than is possible with "e Us4al "on and off" system generally used with electrically driven equipment. ~.n units of 15 to 70 ton the capacity .,0^u*afin ts controlled both by varying cvV e?*ne sPeed and by unloading the yiinders of the compressor. Since engine speed can be varied from maxi mum to less than half of maximum this more than doubles the usual advantages obtained from unloading. On the smaller units, the capacity modulation is controlled entirely by engine speed variation. AH capacity modulation is auto matically controlled. 3 TO 70 TON RANGE Unit capacities range from 3 to 70 tons for air conditioning and multiple unit installations of more than 150 tons are in successful operation. Compressor units are adaptable for use with evaporative condenser, heat ex changer or radiator cooling of the engine. Water cooled manifolds are standard on some models and available on all models. Engine starting is by either storage battery or AC Motor. AH units are supplied for operation on Natural Gas, Gasoline, Propane or Butane fuels. , Units of 15 ton and larger are also available for operation on Diesel fuel. 1315 Air System Equipment SSlSf1* eZ/lW^UltUm ENGINEERING. INC. 7250 East Slauson Avenue, Los Angeles 22, California. pHRECOILIDi] Manufacturers of Air Conditioning and Commercial Refrigeration Equipment TftADt MARK RCC. RECOLD AIR CONDITIONERS AND INDUSTRIAL REFRIGERATION UNITS Outstanding in appearance, performance and versatility, these units have pleasing rounded corners and sparkling blue-grey hammertone finish. Totally enclosed units, with large access doors to motor, expansion valves and coil connections. Capacities: Air Conditioners up to 50 tons; Industrial Units up to 15 tons Air Conditioning Units; Multi-Zone Air Con ditioners; Commercial and Industrial Coolers; Ammonia and Freon Units. . Illustration shows manner in which duet connections can be made in both horizontal and ver tical directions. Recold Multi-Zone Air Conditioner COOLING AND HEATING COILS For direct expansion, chilled water, hot water and steam. Complete range of sizes to meet all conditions and capaci ties. "DRI-FAN" EVAPORATIVE CONDENSERS AND "DRI-FAN" COOLING TOWERS. Capacities from S to 160 tons. Diagram Showing How "Dri-Fan" Principle Oper ates. Wavy arrows denote warm inlet air stream, ether arrows show discharge of moist air. Fan is placed in dry incoming air stream, preventing rust and corrosion. Unique construction provides completely sealed access doors without the use of gasKew of any kind. Galvanized construction. Write for Complete Catalog and Name of Nearest Distributor 1316 Air System Equipment 1101 N. Governor St. 1 Evansville, Ind. Manufacturers of compressors and Condensing Units for commercial refrigeration and for. industrial air conditioning and comfort cooling. The industry's unique line of compressors from 5 to 60 hp, with 100 per cent interchangeability of all wear ing parts. Forced feed lubrication, Modern Automotive design for high efficiency and satisfactory service. The Industry's Low Cost, Compact and Rugged Compressors Ideal for multiple installation in close space requirements. Known 'for high efficiency and low price. Direct drive compressors available in 15, 30, and 60 hp. Designed for use with Freon-12 or Methyl-Chloride refrigerant. MODEL T COMPRESSOR 5 hp to 15 hp MODEL FC CONDENSING DNIT 10 hp to 30 hp MODEL F COMPRESSOR 10 hp to 30 hp MODEL EC CONDENSING UNIT 20 hp to 60 hp THERMATROL or Cylinder Unloading Capacity Control Schnacke patented Thermatrol provides modern capacity control with utmost simplicity--self contained cylinder un loading at start or for capacity control also available for the actual degree of control required. 1317 I Air System Equipment Fans and Biowo* Aladdin Heating Corporation 1111 West Ave. 137, San Leandro, Calif. Manufacturers of Centrifugal Blowers, Heating and Ventilating Equipment. . BB FAN--Backwardly inclined blade fan with non-overloading horsepower charac teristic. Manufactured in 22 sizes, single and double width, all arrangements, 2 classes of construction. Request Bulletin 605-A, 605-B. FC FAN--Forward curved fan, slow speed for quiet operation. Manufactured in 22 sizes, single and double width, all arrangements, 2 classes of construction. Request Bulletin 605-A, 605-C. RB FAN--Radial blade fan well suited for handling grease or other sticky materials Manufactured in 13 sizes, single width only, all arrangements, 2 classes of construc tion. Request Bulletin 450-B, EX FAN--Radial blade fan used .chiefly for conveying materials, fume exhaust, etc. Manufactured in 15 sizes, single width only, all arrangements, 5 classes of construc tion, 3 wheel types. Request Bulletin 461. UTILITY SETS--Self contained units for a wide variety of ventilating applications. Manufactured in 12 sizes with forward curved rotors, 10 sizes with backwardly in clined blade rotors, single width only. Request Bulletins 610, 611. FC JUNIOR FANS--Self contained direct connected fans with forward curved rotors. Manufactured in 4 sizes with 9 motor speeds, single width only. Request Bulletin fil BV Unite Roof Ventilator Futeair Ceiling OtUleil l. HV UNITS--Heating and ventilating unit of universal design. Can be furnishe with air filters, face and by-pass dampers or mixing box. Manufactured in 7 siz with unlimited flexibility as to arrangement. Request Bulletin 610. ROOF VENTILATOR--Backwardly inclined blade centrifugal type. Manufactured in 12 belt driven and 12 direct driven sizes with steel, aluminum, copper or stainie steel housings. Request Bulletin 410. CEILING DIFFUSERS--Fuseair ceiling outlets are manufactured in a complete range of sizes in both supply and combination supply and return types. Requ Bulletins 5$ and 615. 1318 , Air System Equipment Fans and Biowem American (((wilbwp Corporation --;> 3604 Mayflower Street, Jacksonville 3, Florida Exhaust Fans and Related Equipment (or Industrial and Home Cooling .. Authorized Distributes and Dealers in Most Communities . ;;... \ District Representatives: Atlanta, Ga.--John L. Underwood Co.. Inc., 555 Whitehall SL, S.W., Atlanta 3, Ga. Phone Mom 7878 Cincinnati, Ohio --Halsey E. Kendrick, 5167 Valley Ridge Hoad, Cincinnati 11, Ohio, phone Humboldt 4573 Dallas, Texas-J. D. Clower, Whitewright, Texas. LD Phone, Whitewright 919F2. .. . Jackson, Miss.--Bert White, P.O. Box 4264, Fondren Station, Jackson 6, Miss., Phone 6-4853 New Yorx, N. Y.--E. R. Dexter, 117 N. Middletown Rd., Pearl River, N. Y., LD Phone Pearl River 5-2725 Washington, D. C.--Robert A. Magee, Drayden, Md., Phone Gieat Mills 347J2, Wire % Western Union. Leonardtown, Md- COOLAIR BELT DRIVE FANS are specifically engineered to move l&rge volumes of air quietly and at low cost. Certified Ratings: Coolair Fans are rated in accordance with the ASHVE Standard Test Code for Centrifugal and Axial Fans (1938). In addition, most sizes up to and including 62-inch are rated by the A&M College of Texas. Exclusive Ball Bearing Hub with sta tionary shaft and ball bearing motors insure long life and permit mounting in any position. closed, and explosion proof motors for all types of service. Types S and SX--Recommended for large industrial applications where large vol umes of air must be handled. Heavy duty, double frame construction with special pillow-block, ball bearing drive. Small Fans and Accessories--A complete line of Window Fans, Direct Drive Fans, Attic Packages, Ceiling Shutters, Wall Shutters and Guards. Write for descrip tive bulletins. - CONDENSED PERFORMANCE DATA and DIMENSIONS Coolair V-Belt Drive R-rhattgt Fans TYPE H (Ultra-quiet, spring-mounted) (Blade dia. | (inches) Single or Twin Units--To simplify space problems Coolair Fans through the 50- mch size are available in twin units hy a single motor (U. S. Patents 2108738 & 2191418). commercial use where ultra quiet opera- l? squired, these slow speed units itn integrally mounted spring suspen- in (U S. Patent 2191418) are recom- ended. Most models available with ^-speed motors. Types C and CT (Twin)--For heavy duty ommercial and industrial applications, ir.!re high output units are Available without motors or ed with standard semi-enclosed, en Ovtjail hp rpm cfm (free air) Dim. (inc aes) Ht. Width 26 Vi 490 4350 32 Vi 420, 475 7750, 8600 38 Vi 330, 367 9800, 11050 44 vs, a 291, 326 13300, 14650 50 >4, H 284,318 17250,19300 56 %,% 242, 272 20000, 22500 62 Vi, % 216, 241 24400, 27200 30% 36% 42% 49 55V* 61%] 67% 30% 36% 42% 49 55V* 61V* 67% Two-speed units available in all sizes TYPE HT (Ultra-quiet TWIN UNITS) 26 32 VS , 468 8400 vs, vs 361, 420 13000, 15450 30% 61% 36% 73% 38 vs 310 18700 42% 85% 44 % 300 27200 49 98 50 274 33300 55V* 110% Two-speed units available in all sizes below I hp ______TYPE C (Commercial, Rigid Frame) 26 % to V* 612 to 780 5450 to 7200 32 V* to % 502 to 651 8200 to 10450 38 V* to 1 367 to 552 10000 to 14700 44 V* to 1V* 330 to 494 13250 to 19450 50 % to 3 318 to 496 19300 to 30000 5B H to2 272 to 370 22500 to 30000 62 1 to 3 261 to 369 29300 to 41500 30% 36% 42% 49 55 IS 51 VS 67VS 30V* 36% 42% 49 55V* 61V* 67% TYPE CT (Commercial Twin Units) 26 Vi, V* 32 VS, H 38 U, 1 44 1 50 1VS, 2 557, 612 441,523 378, 448 330 320.351 9800 to 10900 14600 to 17100 20600. 23800 26500 38600,42600 30%] 61% 36% 73% 42% 85% 49 98 55V* now TYPE S (Industrial Units) 72 11 to 5 1155 to 2701 35000 to 600001 75HI 75)* 84 1 2 to 7V* |l70to270| 58000 to 85000| 87 1 87 TYPE SX (Industrial Units) 96 3 to 10 150 to 225 SOOOO to 120000 99 99 108 5 to 15 150 to 215 110000 to mvs 11IV* 154000 1319 I jHf f ! ; .1 11 .3 :l Air System Equipment F*n nd Bienr4 The Barry Corporation 714 Pleasant Street, Watertown 72, Mass. Representatives.in the Following Cities: Atlanta Baltimore Chicago'Cleveland Dallas Detroit Kansas Citt Los Angeles Minneapolis Lexington, Mass. (New England) Great Neck, ^- Lonq Island (New York City) Philadelphia Phoenix Rochester, N.Y. St. Loots San Fban-3^ cisco Seattle_Washinoton, D.C. Toronto Montreal^'?. Barry Fan Isolators "V These unit isolators are specifically:^.' designed for use with fans, blowers,^ ventilators, and air-conditioning units. They are highly efficient in reducing J building-borne vibration and noise from ; such machines. They are available in a wide range of load ratings, to permit exact selection to meet varying load requirements at different support points in an installation. The elastic element is oil-resistant neoprene, acting in a combination -jof compression and shear to provide high static deflection under load, and maximum^ stability of the mounted equipment. They are the isolating elements in the hanger v mounts and the rail bases illustrated. Dimensions are 334 in* by 334 in., by l%g in. high. These special rail bases incorporate the Fan Isolators described above, in a welded steel channel manufactured to the specific requirements of each installation, on order only, to ensure proper performance. They are also available with an`integral motor base welded to the rail structure. Threaded holes for the attaching bolts are provided in the upper rail, at points that exactly match the mounting holes of the equipment itself. Width 3% in., height 1J46 in. Length is fixed by individual installa tion requirements. Barry Hanger Isolators These units are highly efficient in re ducing transmitted noise and vibration from ceiling-mounted installations. They incorporate the Barry Fan Isola tors in a steel U-strap mounting spotwelded to the isolator djase plate. Their shallow construction economizes on over head space. 1320 i Air System Equipment * Blowers Bayley Blower Company 1821 S. Sixty-Sixth Street Branche. in Principal cities Milwaukee 14, Wis. Engineers and Manufacturers of Fans, Washers, Heaters and Other Air-Handling Equipment Vent Set CENTRIFUGAL FANS Bayley offers a complete selection of types, sizes and arrangements of centrifugal fans for ventilating, conditioning,, industrial, and mechanical draft service, with slow-speed, power-limiting, or medium speed wheels. Made in single or double widths, with capacities up to 300,000 cfm or more. Smaller sizes have reversible hous ings for convenience and economy. INDUSTRIAL FANS Bayley Industrial Fans are available in a wide range of sizes and constructions from which to select the unit best fitted for any application in exhausting, conveying, cleaning, drying, blast, draft, or similar duties. Type "EX" is proportioned primarily for medium pressures and capacities usually encountered in materials handling or exhaust. Type "H" is similar, but proportioned for relatively higher pressures and smaller volumes. Designs are adaptable to suit virtually any requirement of tempera ture, corrosion-resistance or other severe operating conditions. VENTILATING FANS Type "F" Fans are equipped with wheels having forwardcurved floats, effecting a slow-speed characteristic. The floats of the wheels supplied with Type "AP" Fans are backwardly. inclined, producing a non-overloading characteristic. Choice of fans is determined by the design conditions of the individual installation. Type *`AP" Wheel VENTILATING SETS--Compact, unitary Ventilating Sets are manufactured with drive complete, ready to use, direct-connected and belted styles with capacities to 15,000 cfm. These handy units serve a wide variety of applications in ventilation and exhaust, for kitchens, lavatories* gymnasiums, restaurants, garages, halls, hospitals, laboratories, industrial plants, and many other locations. May be used for supply, exhaust or both. They can be equipped with weather-protection hood for outdoor or penthouse installation. Carefully engi neered and sturdily built to give long-lasting, efficient service. AIR WASHERS Because Turbo washers atomize by mechanical means, they cannot clog, hence are admirably suited to handling air contaminated with particulate mat ter. Standard pressure-nozzle washers also available for use where dust content is light. Turbo Waaker BLAST HEATERS--The finless, long-lasting iron pipe coils of Chinook Heaters will not clog, therefore maintain full capacity longer. Pipe-within-a-pipe arrangement has single header for supply and return, cannot short-circuit, and absorbs expansion and contraction without damaging stresses. A size and type for any blast heating application. . Chinook Heater . 1321 i ' Air System Equipment . and Biowor The Bishop & Babcock Mfg. Co. Massachusetts Blower Division 4901 Hamilton Aye. Cleveland 14, Ohio. P.F. (B.C.) SQUIRREL CAGE AND POWER = FIXED FANS Squirrel Cage (forward curve) and Power Fixed (Backward curve) Fans available in a complete range of sizes--single or double width. For all types of commer cial and industrial air conditioning and exhaust systems^ Bulletin 101 (P.F.) Bulletin 105 (S.<3.) MASSACHUSETTS UNIT HEATERS AND AIR CONDITIONING UNITS Both floor and ceiling mounting arrangements available. These units are built in sections to facilitate efficient handling and erection. Offered in a wide range of popular sizes with various heating and cooling coil combinations. Bulletin lit (Unit heaters) No. ISO (A.C. Units) POWER ROOF VENTILATORS Propeller fan type features a steel ven turi-type inlet orifice, belt or direct drive. Power fixed type has backward curve wheel, belt or direct drive. Both offered in a wide range of competitive sizes. Bulletin No. 118 (Power fixed) No. 119 (Propeller fan). ii * BELT OR DIRECT DRIVE UTILITY TYPE VENTILATING SETS Belt drive wheel diameters 7 in. to 30in., direct drive 6 in. to 13*/ in. Both avail able in popular competitive sizes. Bulletin No. 109. PROPELLER FANS New venturi-type propeller fans. Belt drive 24 in. to 48 in. wheel diameters. Direct drive 12 in. to 30 in. wheel diam eters. A complete line of accessory items ' are available. Bulletin No. 117. DESIGN 2 AIR CONDITIONING FURNACE BLOWERS Available in single, double or special width. All housing and wheel parts are die formed and are offered as complete as semblies or parts only. Bulletin No. 115. Air System Equipment Fans and Blowers Brookside Products Company, Inc. McCordsviUe, Indiana * Manufacturers of-- FANS -- BLOWERS -- VENTILATING EQUIPMENT POWER-FLO 100 SERIES BLOWERS Sturdy built with blades riveted to a back plate and inlet rim welded to blades. Constructed for medium high pressure appli cations in exhaust systems in sizes ranging from 14)4 in. di ameter to 60 in. diameter. Backward inclined blades to guarantee low noise level. Single and double inlet. Non-over loading. Features both statically and dynamically balanced. In Steel, Stainless, Brass. POWER-FLO 200 SERIES BLOWERS This series is designed particularly for the ventilations field where economy as well as ruggedness and efficiency is demanded. Fabricated of lighter gage material for lower pressure ap plications--considerably lighter weight than the 100-SERIES. Riveted throughout. Backward inclined blades. A BRAND NEW DESIGN. Non-overloading characteristics. Both stati cally and dynamically balanced. In Steel, Brass, Stainless, Aluminum. BROOKSIDE SPECIAL BLOWERS Brookside will build any type of blower wheel to customer specifications, either of aluminum or steel. BROOKSIDE SLINGER TYPE FAN BLADES Brookside blades are used by some of the world's leading manu facturers of air conditioning and refrigeration equipment. Several standard models are available for immediate delivery. Special models will be handled where production warrants purchasing of tools. Slinger ring tabs are part of the blades, not an extra piece to work loose or get out of line. Also, you may have a one piece die drawn ring or rolled ring. Resilient hubs if desired. Thousands have been field tested for years. brookside standard prop fans mdels available for immediate delivery in both alumum and steel. Special fans will be made where production Ba'7a"ts tooling. FREE ENGINEERING. 3 or 4 blade-- 0 otations--Almost any blade angle (pitch). 1323 Air System Equipment Biowm Smufafe THE COMPANY 530 N. Park Street Kalamazoo, Mich. SPECIALISTS IN AIR CONDITIONING AND FURNACE BLOWERS Sffriea "X" Blower Assemblies Direct Drive Blower Assemblies Series 800 Blower Filter Unit SERIES "X" BLOWER ASSEMBLIES--For hi-boy, low-boy, counterflow and horizontal furnaces and all types of air-conditioners. Available in top and bottom horizontal and vertical discharge styles. Angular discharge styles available on spe cial order. DIRECT DRIVE BLOWER ASSEMBLY--Permits compact furnace and air-condi tioner design. Motor operates efficiently in any position. No belts or pulleys. 5-speed selector switch optional. Shipped ready for installation, if desired. - SERIES 300 BLOWER FILTER UNIT--5 sizes, 80,000 to 250,000 Btu. Needs only 25 in. x 26 in. to 40 in. x 40 in. floor space. Cabinets of heavy-gauge cold-rolled steel. Finished in durable baked enamel. Standard size replaceable air filters easily reached. Direct Drive Package Unit Series "S" Blower Exhauster Series "T" Twin Blower DIRECT DRIVE PACKAGE UNIT--For 18 in. to 20 in. furnaces. Nheds only 20 in. x 20 in. floor space. No belts or pulleys. Has 5-speed selector switch. Easily re placeable filter. Heavy-gauge steel cabinet finished in durable baked enamel. SERIES "S" BLOWER EXHAUSTER--200 to 2200 cfm. Very compact. Sizes from 17 in. x 12% in. to 29 in. x26 in. Can be fastened directly to wall. Easily made weather proof. Angle of discharge adjustable to any degree. Precision-made of heavy-g&uSe sStEeeRl.IES "T" TWIN BLOWER--For use where large volumes of air must be dis tributed over wide areas. Consists of two blower wheels, heavy scroll housings, polished self-aligning shaft, self-lubricating bearings and rugged metal frame. WRITE^FOR SPECIFICATIONS AND PERFORMANCE DATA 1324 _ Air System Equipment * Pans and Blowers Buffalo Forge Company 450 Broadway, Buffalo, N. Y. Manufacturers of Unit Heaters, Multiblade Fans, Air Washers, Unit Coolers, Drying Equipment, Mechanical Draft Fans, Air Preheaters, Blowers, Exhausters, Disk Fans, Spray Nozzles. Write for Bulletins or Call Your "Buffalo" Engineering Repre sentative In Nearest City Listed Below: ALBANY 4, N. Y., R. B. Taylor, 966 Broadway; ALBUQUERQUE, N. M., H. A. Munn, 730 Haines Ave. N W.- ATLANTA, GA., J. J. O'Shea, 305 Techwood Dr., N.W.; BALTIMORE 1, MD., Machinery and Eauiomenl Sales, Inc., 1012 Cathedral St.; BIRMINGHAM, ALA., J.H. Judd, Room 2226 Comer Bldg.; BOSTON 76, MASS., E. Daniel Johnson, (Melrose Station), 507 Main St.; CHICAGO 6, ILL., Trumbo, Johnson and Heckel, 20 N. Wacker Dr.; CINCINNATI 9, OH IO, J. W. Gibbs, 3047 Madison Rd.; CLEVE LAND 15, OHIO, Sherman A Weager, 570 Hanna Bldg.; CORPUS CHRISTI/TEX., Langhammer Rummel Co., 101 N. Alameda St.; DALLAS 1, TEX., T. H. Anspacher, 615 Tower Petroleum Bldg.; DA VENPORT, IOWA, D. C. Murpny Co., 305 Security Bldg., DENVER 17, COLO., Hendrie & Bolthoff Co., Box 51lOTerminal Annex D; DESMOINES14, IOWA, D.C.Murphy Co.,8405thAve.; DETROIT 16, MICH., Coon-DeVisser Co., 2051 W. Lafayette Blvd.; GREENVILLE, S. C., Roy A. Stipp, 104 E. Stone Ave.; HOUSTON 6, TEX., D. M. Robinson, 2436 South Blvd.; INDIANAPOLIS 4, IND., S. E. Fenstermaker & Co., 937 Architects & Builders Building; JACKSON VILLE J, FLA., H. L. McMurry & Co., 25 River side Viaduct; KANSAS CITY, MO., W. K. Dyer, Post Office Bldg., Mission, Kans.; KNOXVILLE It, TBNN., C. F. Sexton, 702 Empire Bldg.; LITTLE ROCK, ARK.. J. L. Brown, 212 Terminal Warehouse Bldg.; LOS ANGELES IS, CALIF.^H&U&day A Knauff, 448 S. Hill St.; LOUISVILLE t, KY., H. M. Lutes, 633 S. 5th St.; MEMPHIS 5, TENN., C. J. Gaskell Co., Inc., 216 N. Lauderdale Ave.; MIAMI St, FLA., H. L. McMurry A Co., 46 N. E. Sixth St.; MINNEAPOLIS t, MINN., E. Floyd Bell, 2102 Foshay Tower; NEWARK t,-N. J.; Johnson A Norman, 27 Washington St.; NEW ORLEANS It, LA., Devlin Brothers, 1003 Maritime Bldg.; NEW YORK 17, N. Y., Johnson A Norman, 41 E. 42nd St.; OMAHA t, NEBR., Wain Engineering Co., 2311 Douglas St.; PHILADELPHIA t, PA., Davidson A Hunger, 220 S. 16th St.; PHOENIX. AR1Z., J. E. Redmond Supply Co., 625 W. Madison St.; PITTSBURGH tt, PA., H. Lee Moore, 345 Fourth Ave.; PORTLAND 5, OREGON, Arthur Forsyth Co., 921 S. W. Oak St.; ROCHESTER 4, N. Y., R. D. Moyer, 532 Sibley Tower Bldg.; ST. LOUIS 8, MO., J. W. Cooper, 3805 Wash ington St.; SALT LAKE CITY 4, UTAH, Pace-Turpin A Co., 726 S. 3rd West St.; SAN ANTONIO 6, TEX., Langhammer Rummel Co., 300 Blum St.; SAN FRANCISCO 8, CALIF., Richard Stites, 1214 Centra! Tower Bldg.; SEATTLE 99, WASH., Arthur Forsyth Co., 2800 15th Ave. West; SPOKANE 8, WASH., Arthur Forsyth Co., 501 Hyde Bldg.; TOLEDO t, OHIO, Carl M. Eyster, 1118 Madison Ave.: WASH INGTON 5. D. C., G. S. Frankel, 310 Woodward Bldg.; WILKES-BARRE, PA., Power Engineer ing Corp., 517 Brooks Bldg. NEW TYPE "BL" FANS. Used for large systems, they have improved features for higher efficiency, quieter operation and completely stable performance: (1) bell-shaped inlet and duct collar; (2) exclusive "Buffalo" inlet vanes; (3) new rotor with curved shroud matching inlet bell; (4) backward curved blades and new streamlined housing. Capacities to 500,000 cfm. NEW BULLETIN F-100. AXIAL FLOW FANS. Like the "BL" Fans above, these are used for ventilation and exhaust. Their "straight-through" delivery, light weight and compact design make them ideal for mounting in straight duct runs like a section of pipe. For light duty service (to about 3 in. static pressure). BUL LETIN 3533-D. AIR WASHERS. "Buffalo" Air Washers have non-clogging, "Buffalo" Spray Nozzles, trouble-free "Buffalo" Pumps-- simple eliminator plate and tank design for simple mainten ance. May be had in combinations for air spraying, surface cooling, heating or filter cleaning. BULLETIN 3142-D. BREEZO-FIN HEATERS. Will operate on as low as 2 lbs steam pressure. Heater element is a one-piece, seamless copper tube with square copper fins spaced to give maximum radiation. Its "Buffalo" Breezo Fan throws heat efficiently. BULLETIN 3137-E. INDUSTRIAL EXHAUSTERS. Available with interchange able "AW" Air Wheels and "MW" Material Wheels. Allwelded steel plate construction gives smooth interior surfaces for minimum friction loss. Models to handle gases up to 750 deg, also rubber-lined models. BULLETIN 3576. PC CABINETS. Compact central air conditioning units for (1) simple cooling, (2) cooling and de:humidifying, (3) heating and humidifying, (4) continuous air cleaning. Ver tical floor types, horizontal suspended types and units with air washer sections like the model shown. Equipped with "Buffalo" fans and pumps. BULLETIN 3703. 1325 Air System Equipment Century Fan & Ventilator Co. 45 Cedar Street^ _ Stamford, Conn. CENTURY INDUCED DRAFT FAN For Low and High Pressure Heating Plants. A mechanical device for creat ing a uniform draft regardless of weather conditions, resulting in complete com bustion with high CO* content. For installation in breeching in any po sition. Eliminates high unsightly chimneys. Air System Equipment * Fans and Blowers CHAMPION BLOWER & FORGE CO. Lancaster, Pa. Address Correspondence to Div. 9 . Manufacturers of Blowers, Ventilating Fans and Exhaust Fans for handling air, material and fumes Representatives in Principal Cities Fan No. hp rpm 70* S/P ' Oil Burning Rato--gal hr Inlet Outlet MD1A ia MD1B 18 M X 1725 1725 2000 cfm 2700 cfm X' %' 20 27 20* x 20' 20* x 2O' 19* 19* MD1 21 X 1725 4500 cfm %- 45 23' x 23' 22* MDl 24 l 1725 5800 cfm XT 58 26' x 26' 25' MD1 27 IX 1725 7300 cfm X' 73 29' x 29' 28' Complete with totally enclosed motor, stainless steel fan, 10 gage welded housing, manual speed controller magnetic starter. CENTURY CYCLONE ROOF FAN Dynamically and statically balanced, compact and systematically designed. Very quiet and efficient. Ideal for school and hospital buildings. Copper, galvanized and aluminum hous ing. Rated in accordance with test code as adopted by NAFM and ASHVE. Fan Size 16 19 22 25 28 31 34 37 43 50 56 52 Fan rpm 1350 980 1070 900 850 750 790 595 620 490 590 450 500 450 500 390 400 340 350 300 300 250 280 240 Motor hp X X X w X X X X 1 X ix 1 1M 1 2 iX 3 2 3 2. 3 2 ran Tip Speed 5290 3850 5040 4230 4650 4120 4960 3730 4390 3160 4640 3540 4330 3890 4710 3675 4390 3730 4480 3850 4310 3600 4450 3830 BELT DRIVE CFM Free Air 1640 1270 2620 2380 3640 3250 4640 4200 5860 5250 6920 6300 8400 8160 10200 9100 14800 12500 19000 16600 23400 19600 26700 23600 cfm X" 1585 1160 2525 2200 3500 3100 4450 3975 5650 4950 6730 6100 8250 8000 9900 8650 14500 12250 17900 16500 22600 18500 25400 22500 For quiet operation select fans with Tip Speed 4500 or lower. STATIC PRESSURE cfm X" 1520 1000 2390 2100 3350 2870 4200 3975 5360 4520 6530 5750 7990 7590 9500 7900 13900 11200 17000 15000 21700 17400 24200 21200 cfm X" 1335 725 2250 1825 3160 2660 3900 3450 4930 4100 6200 5400 7500 7000 9200 6900 12800 10200 16400 13800 20500 15700 23000 19150 cfm X" 1300 590 2050 2925 2050 3680 3160 4300 3460 5540 4970 6850 8250 6230 12000 . 7600 f 14800 11700 18700 12000 21800 15000 1326 cfm X 1125 1780 1250 2550 1485 3250 2650 3620 2930 4950 3920 5885 4850 7200 5000 9000 i3000 9000 16200 18900 12500 CHAMPION TYPE "D" VENT SETS whreeTsDunaltVe?nilati0in f tyPeS equipped with backward curved non overloading drive and weoin f6ter' furnisbed complete with electric motor, adjustable and weather proof covers if required. Champion Cast Iron Housed Fans of and 0f18 ^Pes b)r fume hood exhaust he r ban<lling corrosive gases. Can nn et^ulPPe^ with either plain steel or n ferrous blast wheels, interior of 8non-Inig and wbeel Can be covered with 1 corrosive resisting coating. Champion Forward and Backward Curve Ventilating Fans and Exhaust- Blowers manufactured in sizes up to 60 in. dia. Fans also furnished,in all standard arrangements with.Ball, Bab bitted or Water Cooled Bearings as re quired. ' 1327 Air System Equipment / ' fHMERBO BLOWER 'ION 9867 Pacific Ave., Franklin Park, 111. Gladstone 5-4780-Write for Bulletins Ala., Birmingham Ahiz., Phoenix Ark., Little Rock Calif., Los Angeles Calif., San Francisco Colo., Denver Conn., New Haven Fla., Jacksonville Fla., Miami Ga., Atlanta III., Chicago III., Rockiord Ind., Fort Wayne Ini>., Indianapolis Kt., Louisville La., Shreveport . La., New Orleans Md., Baltimore Mass., Boston Mass., Springfield Mich. , Detroit Mich., Grand Rapids Minn., Minneapolis Miss., Jackson Mo., Kansas Crrr Mo., St. Louis Mont., Billings Nebr., Omaha N. M., Albuquerque N. Y., Bbooeltn N. Y., Buffalo N. Y., Rochester N. Y., Syracuse N. C., Charlotte N. D., Fargo Ohio, Cincinnati Ohio, Columbus Ohio, Dayton Ohio, Toledo Okla., Oklahoma City Orb., Portland Pa., Erie Pa., Philadelphia Pa., Pittsburgh Tenn., Chattanooga Tbnn., Knoxville Tenn., Memphis Tenn., Nashville Texas, Dallas Texas, El Paso Texas, Fort-Worth Texas, Houston Texas, Lubbock Utah, Salt Lake City Ya., Richmond D. C., Washington Wash., Seattle Wash., Spokane Wis., Milwaukee New aerodynamic blade design NEW AIRFOIL CENTRIFUGAL FANS DESIGNED FOR HIGH PRESSURE SYSTEMS Greater Efficiency, Quieter Operation . for industrial, commercial and all other heating, ventilating and air condition ing applications. Efficiencies in excess of 90 per cent. Steep pressure characteristic curves. Noise level ratings .lower than flat- bladed backward curve fans. . Certified ratings. All drive arrange ments; directions of rotation and dis charge. 600 to 750,000 cfm to 32 in. sp. Class I to V construction. Wheels 12 to 123 in. diameter. Bulletin A-101. Air System Equipment Fans and Blowers Clarage Fan Company Kalamazoo, Michigan In Principal American Cities ' (Consult Telephone Directory) Clarage Air Handling and Conditioning Equipment For nearly a half century Clarage has been a leading manufacturer of equip ment and units for ventilating, exhaust ing, cooling, air cleaning, humidifying and complete conditionings Clarage equipment is designed to meet all types of industrial, commercial and public building requirements. For other equip ment in the complete Clarage line see "Air Conditioning--Central Systems." Clarage Fans for ventilating and air conditioning are offered in many differ ent standard types and arrangements. Capacities range from 200 to 725,000 cfm. Axial Airfoil Fans for removing fumes, vapors in dangerous locations. 1100 to 105,000 cfm. Bulletin AA-10I. Axial Mushroom Roof Exhausters for industrial, commercial ventilation. 870 to 47,800 cfm. Bulletin CAM-102. Gyra-Flo Roof Exhausters--Extremely quiet for schools and hospitals. 830 to 29,750 cfm. 61 to 88 db. Bulletin GPE- W2. . , Centrifugal Fans for heating, ventilating, air conditioning, all drive styles. 600 to 750,000 cfm. Bulletin C-101. Propeller Fans for commercial, indus trial, business, home ventilation. 1200 to 24,100 cfm. Bulletin CEF-102. Steel Plate Fans for removing dust, ma* terials or high temperature air, gases. 200 to 50,000 cfm. Bulletin SPE-I0S. Turbo-Pressure Blowers for oil or gas burners in industrial furnaces, ovens. 80 to 5500 cfm. Bulletin CTB-102. MD Fans for commercial ventilation. Direct or belt drives. 300 to 17,000 cfmBulletin MD-102. Clarage Unit Heaters are available for either floor or suspended installation. 23_,sizes range from 24,000 to 1,160,000 Btu. They can be operated on either steam or hot water. ' Clarage Industrial Fans (shown above) range up to 130,000 cfm, 18 in. sp, and 60 in. inlet diameter. Can be constructed for special applications. Clarage Ready Units (left) are furnished complete ready-to-run. V-belt or direct connected: Capacities to 12,000 cfm. We welcome your Inquiry on any air handling or conditioning problem. Con tact our nearest branch office, or write us at Kalamazoo, Michigan. 1329 Air System Equipment * Bbm DeBothezat Fans Division American Machine and Metals, Inc. Main Office and Factory--East Moline, Illinois FOREIGN SALES OFFICE: WOOLWORTH BUILDING. NEW YORK 7. N. Y. SALES ENGINEERING OFFICES IN ALL PRINCIPAL CITIES LOOK IN YOUR TELEPHONE DIRECTORY UNDER "FANS" OR "VENTILATING EQUIPMENT" ft ft Power-Flow Roof Ventilator FOR CONTROLLED VENTILATION DeBothezat Power-Flow Roof Ventilator is a motor driven fan in a weatherproof housing, guaranteed to provide positive ventilation at all times. Can be used for air exhaust or intake, either with or without duct systems. Low, streamlined design blends well with modern architec ture. Available with fan wheels 12 inches through 48 inches in diameter, with ca pacities up to 40,900 cfm. Write for Bul letin DR-8-52. DeBothezat Vertical Discharge Roof Ventilators exhaust oil or dust laden air straight up at high velocity. Available with fan wheels 16 inches through 48 inches in diameter, with capacities up to 40,900 cfm. Write for Bulletin DR-27-50. FOR SPOT COOLING DeBothezat "Hy-V" Air Jets blow a directed stream of cooling air as far as 65 feet without the use of ducts. Available with bracket for wall mounting or equipped with portable wheeled stand. With fan wheels 18 inches through 30 inches in diameter, and nozzle velocities up to 5,780 fpm. Bulletin DH-8-51. Bifurcator FOR FUME REMOVAL DeBothezat Bifurcator is a motor driven axial-flow fan in a divided housing, for exhausting air that is abnormally hot, corrosive, flammable or explosive. De structive fumes are by-passed' (bifur cated) around the motor, which is mounted in a separate chamber so that it remains cool, clean and easily acces sible. Bifurcator Fans install^directly in the duct, at any angle. Available with fan wheels 12 inches through 48 inches in diameter, with capacities up to 45,000 cfm. Bifurcator can be equipped' with base and weather head for exterior mounting. Write for Bulletin DB-4-58. FOR CONSTANT BOILER DRAFT DeBothezat Induced Draft Bifurcators provide controlled draft for boilers and furnaces, eliminating the need for large costly stacks. For high-pressure boilers delivering up to 60,000 pounds of steam per hour and for low-pressure boilers up to 190,000 EDR. Bulletin DB-82-52. FOR GENERAL VENTILATION DeBothezat Axial-Flow Vent Sets are built with fan wheels from 16 inches through 48 inches in diameter, with capacities up to 50,600 cfm. Write for Bulletin DV-2-52. . Panel Vent Sets are moderately priced units for operatio against lower static pressure. Bulletin DV-81-51. ., Capacity ratings for DeBothezat Fans have been from wind tunnel tests in accordance with the Standard 1 & Code for Axial-Flow Fans and conform with U. S. Commerce, Commercial Standard 178-51, which embodies t test code of A.S.H.V.E., NAFM and PFMA. 1330 Air System Equipment Fans and Blowers Garden City Fan Company 332 South Michigan Avenue Chicago 4, Illinois Representatives In principal industrial cities. Manufacturers of Design "B" Multiblade--Non-Overloading--Hi-Static Cycloidal Standard Steel Plate and Small Exhaust Fans. Wheels designed in forward curved, backward curved and radial bladed types, adaptable to commercial and industrial applications. Suitable for cooling, evaporating, drying, air-conditioning, ma terial conveying and disposal, processing foodstuffs and animal or mineral products and by-products, induced draft, paint spray and fume removal, packaged steam generators, and requirements for fan and blower systems. Standard Steel Plate fans also produced for high temperature operation 300 F to 1600 F, N.O.L. fans to 600 F, and Design 4*B" Multiblade fans for temperatures to 800 F. Non-Overloading Fan illustrates an an gular up discharge position. Fan in terior coated with resistant paint. Backward curved fan blades. Large Design "B" Multiblade fan for temperatures to 800 F, showing insulated cup and air-cooled fan shaft. Forward curved fan blades. Hi-Static Cycloidal Fans--used for sys tems handling and conveying many ma terials. Specially designed fan blade reduces power requirement and operates at slow speed. Small Exhaust Fans--steel plate housing shown. Available with cast iron housin8 and direct-connected motor. Wheels, 9^ in. thru 16 in. O.D. High temperature fans to 1600 F. In sulated or uninsulated housings. Air cooled shaft with ball bearings. Engineering data, information, and catalogs, available upon request. Non-Overloading Fan Design "1?" Multiblade Fan High Temperature Fan Small Exhaust Fan 1331 Hi-Static Cycloidal Fan Air System Equipment Fan^a biTMoi Plant Offices General Blower Company 8602 Ferris Ave., Morton. Grove, 111. Sales Offices in Principal Cities General Centrifugal Fans for complete range of volumes for heating, ventilat ing and air conditioning. Type SS (seal seam) housing construction. < For Industrial applications requiring heavier construction, General offers the type W (Welded) housing construction. General Backward Blade and Forward Curved fan wheels and inlet cones are assembled of spun parts for smooth quiet air movement. Ask for Bulletins'BB102 or FC-105 for particulars. General Propeller Fans supplied with either cast aluminum or steel blades from 10 in. to 72 in., with direct or belt driven arrangement. Bulletin PF101 --> Inlet vane controls of General design are offered for manual or automatic operation. Material handling Exhausters convey air borne particles caused by grinders, polishing or cutting. General Steel Plate Exhausters are suitable for high tern- perature air recirculation. Bulletin MX-104 General Multi Vent sets of FC or BB wheel construction recommended for low cost air handling requirements for ventilating and industrial needs. Direct motor connected units for up to 12 in. fan wheels. Belted units up to 36 in. fan wheels. Bulletin MVS 102 --^ For removal of fumes and foul air where no duct system is required, General offers the Automatic Propeller type Roof Ventilator having vertical discharge. Bulletin PF-101 General Power Roof Ventilator, of low silhouette design having type BB cen trifugal fan wheel meets architectural design requirements. Aerodynamic de sign provides quiet efficient operation. Bulletin RV-101 -->. ALL GENERAL FANS TESTED ACCORDING TO NAFM STANDARD TEST CODE. 1332 Air System Equipment Hartzell Propeller Fan Co. DIV. OF CASTLE HELLS CORP. Piqua, Ohio '<' biowot PROPELLER TYPE FANS Single-Propeller, Two-Propeller and Multiblade. 12 in. to60in. Cast alumi num alloy propellers . . not sheet metal stampings. Standard make motors. Curved orifice air-seal ring provides ex tra air delivery. VANEAXIAL BLOWERS Compact, easy-to-install blowers for moving air against pressures up to 8 in. water gauge. 12 in. to 54 in. diameter. Belt-drive and direct-drive models. Wheel is a single, precision casting of aluminum alloy. Standard NEMA mo tors. Occupy no floor space. ^ COOL BLAST FANS 22 in. to 60 in. Stationary and portable models. Built to withstand heavy in dustrial use. Equipped with totally en closed, ball-bearing motors, conserva tively rated for continuous duty. Utility fan, not shown, 14 in. to 36 in. is shorter, lighter, more easily portable; fan can be revolved 360 degrees vertically. ere is a Hartzell fan or blower to meet any air-moving need--Lo-Noise, Exten sion-Shaft, Pulley-Drive, Duet, Belt-Drive, Panel, Reversible, Cooling Tower and v me. ^ans* Also makers of Centrifugal Blowers, Unit Heaters, Fan-Powered Roof entilators, Penthouses, Intake Air Units, and Farm Crop Driers. Engineering representatives in principal cities. 1333 ' -fp Air System Equipment ^ md (Mm,^ Hunter Fan and Ventilating Co, ' Exclusive Fan Makers Since 1886 400 S. Front Street, Memphis 27 Tenn. Features include: square steel frame for easy mounting, streamlined air inlet,, airfoil blades of high strength aluminum alloy, totally enclosed motors of heavyduty type, permanently lubricated and sealed ball bearings. Explosion-proof motors are available on order. HUNTER PACKAGE ATTIC FANS Compact unit complete with ceiling shutter. Heavy-duty motor, rubber mounted for quietness. Precision bal anced blades. Ball bearings throughout. Built-in fuse link. Simple, inexpensive installation. Resilient rubber cushion on fan frame forms air seal. Fan guaranteed 5 years; motor and shutter, 1 year. Certified air deliveries from 5000 to 15,500 cfm. Underwriters' Laboratories approved. Four models have automatic ceiling shutters. Shutter with integral metal trim (finished in off-white) operates qui etly and eliminates drafts when closed. 9700 cfm model has manual, built-in shutter with pull-chain switch. BELT-DRIVEN FANS For Commercial and Residential Use Capacities from '5100 to 22500 cfm; sizes 24 in. to 48 in. Certified air delivery ratings. Heavy die-formed blades, bal anced for quietness. Ball bearings throughout--sealed against dirt and grease leakage. Thrust type bearings permit installation in any position. Rubber-mounted ball-bearing motors, with built-in thermal overload protec tors. Underwriters' Laboratories - ap proved. Fan guaranteed five years; motor one year. CERTIFIED AIR DELIVERIES Fans tested according to Standard Test Code as adopted by ASHVE and PFMA and air deliveries conform with U. S. DIRECT DRIVE FANS Department of Commerce Standard No. CS For Industrial Uses i78~5t. This new line of industrial fans has blade sizes from 24 in. to 48 in., with certified air .deliveries from 5400 to 36000 cfm. Rigid construction places these fans in a heavy-duty propeller fan class, for serv ice in industrial, commercial and mili tary applications. They are designed to operate against static pressures generally encountered in this field. HUNTER ENGINEERING SERVICE Hunter's Engineering Department will assist you with your cooling and ven tilating problems. See Hunter section in Sweet's Catalog. Write for new man ual "How to Cool for Comfort" giving methods and. installation details. 1334 Air System Equipment cSSuSildF.ns ILG Electric Ventilating Co. 2880 North Crawford Ave., Chicago 41, 111. Offices in more than 40 Principal Cities Propeller Fans* Centrifugal Fans, Unit Heaters, Kitchen Ventilators, Night Cooling Fans ILG Direct-Connected Self-Cooled Motor Propeller Fans Used for exhaust of stale air, fumes, heat, dust, odors, etc. Self-cooled motor com bines protection of enclosed motor with low operating cost of open motor--con stantly cooled by fresh, clean air, circu lated internally--never "gums-up" from contact with foul air--saves 5 to 10 per cent on power costs. Rugged, heavyduty framework. Dynamically-balanced fan wheel, direct-connected to motor. Smooth, quiet, effortless operation-- economical, long lived. ``ONE-NAME PLATE" Guarantee. Certified ratings. Sizes 6 in. to 72 in. ILG Direct-Connected Centrifugal Fans Type "BC"--Load-limiting type with backward curved blades. Motor load remains constant over wide range of air volume and change in static pressure. Wheel mounted directly on motor shaft with motor partially recessed in side of casing. No motor base required. Un obstructed inlet. 10 sizes. Also avail able for belt-drive in 12 sizes. Volume Blowers Type "B" (left)--small volume, low pres sure, quiet running. Multi-blade wheel direct-connected to motor shaft. Castiron base. Universal discharge. 12 ca pacities. Type "P" (right) for exhausting dust, fumes, removal of steam, vapors. Four discharge positions to avoid friction in short bends. Seven capacities. Kitchen Ventilators and Night Cooling .bans Kitchen Ventilators (left)--wide range of sizes, types for mounting in wall, ceiling, or window. Full capacity. Extra-quiet. construction. Headlined by new LC10 Built-in Ilgette shown left above. Cooline Fans (right above)--port able model for circulating or exhausting air at window. For permanent installaf}0n ln attic, use ILu Self-Cooled Motor Propeller Fans. Type "PRV" Power Roof Ventilators Centrifugal fan type, for exhaust from vertical flues or duct systems. Directconnected, self-cooled motor. Non overloading, backward curved wheel. 10 sizes. Up to 13-6 in. SP. 1335 Air System Equipment ma Bbwo, JOY MANUFACTURING CO. General Offices: Henry W. Oliver Building, Pittsburgh 22, Pa. MANUFACTURERS OF VANEAXIAL FANS UNITED STATES AND TERRITORIES Ala., Birmingham 601--10th St., N. (Crandall Eng.) Calif., Los Angeles 22. .6426 E. Washington Blvd. Calif., San Francisco 2....................155 Fell St. Colo., Denver 2 1626 W&zee St. (Scbloss & Shubart) D. C., Washington 6...1000 Vermont Ave., N.W. Ida., Kellogg..................... North 1 Division St. III., Centbaua.......................... Fifth and Chestnut III., Chicago 6................ 560 W. Washington Blvd. Kt., Middlesbobo...........................609 N. 19th St. Mass., Boston 15....................... 88 Brookline Ave. Mich., Detroit 27......................... 14225 Shaefer Rd. Minn., Duluth.......................... 1021 E. Superior St. Mont., Butte.............................. 24 W. Granite St* Mo., St. Louis 10....................4235 Clayton Ave. N. Y., New York 6..............................140 Cedar St. Okla., Commerce....................Ill Commerce St. . Ore., Portland 9......... 1631 N.W. Thurman St. Pa., Forty Fort................................ 155 Welles St. Pa., Pittsburgh 13......................... 4107 Sennott St. Pa., Philadelphia 3___1617 Pennsylvania Blvd. Tenn., Knoxville......................108 W. Main St. Tex., Dallas.................................. 6540 Hines Blvd. Tex., El Paso............................ 1022 Wyoming St. Utah, Salt Lake City 16.. 1359 S. Second West St. Wash., Seattle 4....................... 3410 First Ave. So. Wash., Spokane...........................S. 121 Monroe St. W. Va., Huntington...................742 Eighth Ave. AND MORE THAN 500 DISTRIBU1 IN CANADA Alberta, Calgary......................902 Ninth Ave., W, Nova Scotia, Sidney;....................382 Esplanade Ave. Ontario, Galt.........................................175 Beverly Si Ontario, Kirkland Lake. ..y?24 Duncan Ave.. Ontario, Sudbury..............................................61 Eyre St Ontario, Toronto...................;. .3402 Dundas St., W. Quebec, Montheal.........................................85 Hodge St IN MEXICO Mexico, Mexico City............................Ramon Gusman EXPORT OFFICES N. Y.. New York 1......................Empire State Bldg. Algeria, Algiers Compagnie Joy, S.A.4, Rue Charles Vallin Australia, Rosebery.............56-58 Rothschild Ave Belgium, Anderlecht-Brubsels 52 Blvd. de la Revision Brazil, Rio be Janeiro - Caixa Postal, 54, Copacabana Chile, Santjaoo................................................Casilla 86-D England, London WI........................ 6 Carlos Place France, Paris.........................................30 Rue de Chabrol Fb. Morocco, Casablanca Cie. (M&rocaine) Joy, S.A. Rue de Verdi Northern Rhodesia, N'Dola Joy-Sullivan (Africa) (Pty.) Ltd. Peru, Lima...................................................................Casilla 3111 South Africa, Johannesburg . ' l Steele St., Sleeldale RS THROUGHOUT THE WORLD SERIES 1000 AXIVANE* INDUSTRIAL AND COMMERCIAL FANS Joy Series 1000 adjustable blade tor charts giving pressure-volume range AXIVANE* Industrial fans are available for each fan, write for bulletin number in 136 sizes ranging in volume capacity up to-150,000 cfm with pressures up to 9.6 in. W. G. Housing diameters range from 18 in. to 84 in. For complete speci fications, construction details, and selec- J -611. Joy AXIVANE* Series 1000 fans are efficient, quiet, compact, flexible, and easy to install. ADJUSTABLE BLADES Joy AXIVANE* Industrial Fans have the extra performance flexibility of ad justable blades. Adjustable blades ar standard equipment on all Series 1Q00 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 loosen- Blades are adjustable on the job by looeening one loci nut Cutout draining showing location of motor and corn' pact construction 1336 Joy Manufacturing Co. Air System Equipment "> Blower* Rear view, showing vanes and motor Front view, showing simplicity of construction ing 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. Adjustable blades permit on-the-job correction for unpredictable duct resist ance or for poorly installed duct work. possible with a centrifugal fan. An AXI VANE* fan, installed on an in-line con nection with ventilation ducts, parallel to and close by an overhead structure, may require 70 per cent less space than a conventional belt-driven centrifugal fan. The compactness of a Joy AXI VANE* fan assures a maximum of net operating or rentable area. Fan rooms are virtually eliminated. MORE EFFICIENT Stationary straightener vanes, located immediately behind the rotor, partially recover the rotative energy imparted to the air by the rotor, and re-establish axial flow to the air leaving the vanes. This eliminates excess turbulence at the point where the air enters the duct system-and increases efficiency by decreas ing pressure loss. The Joy AXIVANE* fan utilizes an aerodynamically efficient blade and sta tionary vane design. EASIER TO INSTALL The Joy AXIVANE* Series 1000 fan de velops a greater volume and pressure per pound of fan and motor because of its compact, in-line construction. This light weight permits a simplicity of in stallation that minimizes installation costs and total weight by eliminating heavy foundations, complex duct offsets and elbows, drives, and guards. AXI VANE* fans can be installed quickly and easily, even by relatively inexperienced or un-skilled labor. MATCHED ACCESSORIES QUIETER OPERATION For eclual weight and space the Joy AXIVANE* fan is quieter than a centrif ugal type fan of equal volume and pres- Aytv streamlined airflow from an AXIVANE* fan makes sound insulation a 81n}ple and inexpensive operation when required for the ventilation and air con ditioning Qf quiet spaces such as hospi- auditoriums, radio stations, etc., ''here insulation against system noise must be used. MORE COMPACT Joy AXIVANE* fans are built around e motor, the fan housing becoming an ctual part of the duct system. This P oauces a more compact design than is Inlet bells, screens, and fan supports are accessories designed to fit all AXI VANE* fan housings. In ordering, it is only necessary to state the model number with or without the accessories as desired. If required with accessories, these will be furnished to fit the fan model ordered without special number. No matter how carefully a duct system is planned, an incorrectly selected inlet bell will reduce fan efficiency by increas ing intake turbulence. This excess tur bulence will also increase the noise level of the fan. When a fan takes its air directly from the weather, a plenum, a fan room, or from a duct system larger in circumference than the fan housing, a bell should be used. Reg. U. S. Pat. Off. 1337 Air System Equipment b?0w*wE! : The Lau Blower Company . 2007 Home Avenue, Dept. H, Dayton 7, Ohio Manufacturers of Exhaust and Portable Fans, and Air Conditioning Blowers Direct Drive Blowers- Models DD7, DD9-6, DD9-9, DD9-10 A compact, simplified and inexpensive unit permitting economies in space and installation. Complete blower "package" ... no belts or pulleys. Lau Direct Drive Blowers are made in several standard sizes: DD7, DD9-6, DD9-9, and DD9-10, covering a wide range of capacities. Motors of J-fo hp (DD7 only), 34 hp, or }Jfp are available to fit all DD9 models. Featured also is a LAU adjustable motor-mounting bracket which will fit motors from a number of different motor manufacturers. Ad justable bracket results in greater motor-source selection. ' . Standard Blower Assembly consists of blower wheel, housing with cut-off; and motor. Motor assembled in mounting with neoprene mounting cushions. Standard motors are shaded-pole type; 6 pole, 115V, 60 cycle, A.C. Series "A" Blower Assemblies Housing Base--rigid, braced cross wise. Heavy gage steel. Discharge Outlet--improved design and construc tion. Belt and Shaft--2-stage centerless ground shafting. Bearing Bracket-- 3-point suspension. Same bracket used for various angles of discharge . . Lausteel Pulley--newly improved ... greater strength and performance . . Wheel--Center Suspension, for high and low speed. Offset in Scroll Sides-- reinforces inlet of the venturi for greater strength . . . Bearing Assembly--Lau "Gold Seal," long life, frictionless, self-aligning. New Motor Mounting-- completely adjustable. Permits ANY motor location . . . New Plastic Washer --absorbs shocks. Write for Catalog Pages 707. Mention Blower items you are interested Center Suspended Riveted Wheels Heavy gage steel construction with blades double riveted to end rings and arc welded to center disc. Diameters 18 in. through 30 in. Available.with stand ard steel hubs or Power Lock hubs- Series "A" Spun Wheels Superior design, with center disc construction assures maximum per formance. Finished baked enamel, also in Ruspruf or hot dip galvanized. Available with standard steel or Power Lock hubs. . S.I. and D.I. Weld Wheels Lau Single and Double Inlet Weld Wheels have individual blades of correct length, width and pitch, machine balanced. In baked enamel, Ruspruf or plated finish. Dia. from 434 in. through 9 in. and widths 2)4 in. through 9 in- 1338 Air System Equipment Bearings, Pulleys Pillow Blocks, Fans The Lau Blower Company 2007 Home Avenue, Dept. H, Dayton 7, Ohio Manufacturers of Exhaust and Portable Fans, and Air Conditioning Blowers Lau Series "A" and Gold Seal Bearings SERIES "A" BEARING (at far left). Self-aligning, frictionless, self-oiling Bronze bearing. Held in the housing under uniform spring pressure. "LAU PAK" GOLD SEAL BEARING (at left) requires no lubrication. Ample supply of plastic petroleum is sealed in housing. Long-life, trouble free, noted for its outstanding performance whereever used. Lau Self-Aligning Pillow Blocks Light weight, oil-tight steel housing. Bearing projects beyond edge of housing providing a self-lubricating seat. Durex bush ing feeds oil to shaft by capillary action. Large reservoir. Spring acts to keep spherical surface of bearing and ring in close contact. Spherical bearing surface assures full self-alignment. Long bolt slots permit interchanging with other pillow blocks. Bore sizes % in. through 1% in. Write for Blower Catalog Pages 707. Mention issues of interest to you. Lau Constant Speed PULLEYS AND Variable Speed PULLEYS LAUSTEEL pulley--Constant speed pulley is suitable for use with both "A" and "O" Section belts. It is available in diameters of 6 in. to 10 in. inclusive. Gives better performance . . . less friction . . . longer belt life. LAUSTEEL variable speed pulleys and the cast iron variable speed pulleys are available with any one of three (3) standard bores. Each type allows speed variations up to 30 per cent thus assuring noiseless efficient operation for many drive combinations. Write for Lau Fan ^txtalog 715 Contains full details and complete specificatln data. Ask for a copy. Famous Lau "Niteair" Exhaust Fans Panel Unit at Right, Rancher Fan at Left Lau "Niteair" Panel Units for Resi dential, Commercial and Industrial use (standard and heavy duty models) in five (5) sizes: 24 in.-30 in.-36 in.-42 in. and 48 in., with four blades properly pitched for greatest suction and air movement. Lau "Niteair" Rancher Fans for dwellings with low-pitched roofs pull air UP thru ceiling opening. Four (4) sizes: 24 in.-30 in.-36 in.-42 in. All Lau Fans carry PFMA Certified Ratings and UL Approval. Guaranteed 5 years; motors carry 1 year manu facturer's warranty. 1339 Air System Equipment Morrison Products, Inc. A 31 Year Firm East 168 Street and Waterloo Road, Cleveland 10, Ohio Mk % r- ''-"5 Air System Equipment . l? THE NEW YORK BLOWER COMPANY SALES OFFICES 3145 SOUTH SHIELDS AVENUE CHICAGO 16 FACTORY, IAPORTE, INDIANA Representatives in Principal Cities ' FANS BLOWERS UNIT HEATERS MAKE-UP AIR UNITS HEAVY DUTY HEAT SURFACE MORRISON BLOWER WHEELS-- Equalized Weight Distribution with Made Exclusively for original equipment end mounting. No shaft whip--reduced manufacturers in heating, ventilating deflection. and air conditioning. Available with Morrison Blower Morrison Blower Wheels are double Wheels is Complete Engineering Service. width--double inlet in standard dia Included are templates, shop drawings, meters from 10 in. to 16 in., and in tables, data, cost analysis, graphs, width from 6 in. to 16 in. One-Piece Blade Construction. ThreePiece Balanced Assembly--one-piece blade and two pressed rings with integral charts, sources of component parts. Housing Squares and Scroll Sides avail able for Low Cost Assemblies. Catalogs: Morrison Blower Wheels hubs welded together. --Copies Mailed Upon Request. 1340 MIS--15,000 cfm M15--A unit that delivers, warmed, filtered, outside air to industrial spaces to replace exhausted air and balance minus pressure. Corrects drafty conditions and uncontrolled in filtration. Made in 4 sizes from 5,000 cfm to 20,000 cfm. De scribed in Bulletin 523. Type ME Centrifugal Fans--Capacities up to 101,000 cfm. Slow speed wheels offered from 7\ to 73 in. Capacities up to 123,000 cfm. Quiet operating (PL) medium speed wheels with non-overloading horsepower characteristics for heating, ven tilating and air conditioning or industrial applications. Wheel diameters from 18 in. to 73 in., with any speed or discharge required. Class. I, II, III or IV construction. Write for Bulletin 493. Steelfin Hot Blast Heating Surface--Extra heavy duty, finand-oval tube, all-steel, welded construction. A hot dip metallic coating over all, including headers, affords perfect bonding and conductivity. Suitable for continuous heating service on steam pressures up to 150 lb. Bulletin 492. nyb Propeller Fans--Deliver large volumes of air at low re sistance and low current consumption. All wheels are machine balanced for smooth, vibrationless operation. Made in two types and eight basic sizes. Wheel diameters from 12 in. to 48 in. Direct or belted drive. Capacities from 400 cfm to 23,500 cfm. Ask for Bulletin 511. nyb Unit Heaters--Heavy duty, welded steel, fin-and-tube heating element. Suitable for continuous heating service on steam pressures up to 150 lb or more. 10 sizes with capacities from 30 Mbh to 490 Mbh. Bulletin 513. Type GI Industrial and Heat Fans--For dust and gas removal, conveying of materials and handling hot gases. Housings, drives, and discharge arrangements to meet any requirement. Wheel diameters from 10 in. to 66 in. Capacities from 450 cfm to 60,500 cfm. Details and engineering data in Bulletin 621. General Purpose Fan General Purpose Fans--Portable, self-contained units for Class I industrial and ventilating applications. Recom mended for ease of installation, low maintenance and space saving features. Made in three types and eight basic sizes. Capacities 400 cfm to 18,000 cfm. Bulletin 512. 1341 i! . ]. ; j: . i, t: , ! f! ! 1 .. PEERLESS PVS EXHAUST FANS Motor and fan designed and built by Peerless. Permanent split capacitor type motor is totally enclosed. Furnished with controller for 1 or 2-speed opera tion. Mounts with 4 or 6 lag screws. PEERLESS PVB INDUSTRIAL EXHAUST FANS For general use in factories, warehouses, foundries, etc., and in ducts where low static pressure resistance is met. Ball bearing construction. Vertical or hori zontal mounting. Single phase or three MODEL NO. PV-0 PVS-1 PVS-2 PVS-16 PVS-18 PVS-24 PVS-30 CAPA CITY CFM 400 1350 1750 2150 2900 4550 8800 MOTOR RPM HP HIGH 50 Watts Ho Ho 14 H V4 H 1400 1600 1600 1100 1100 82Q 820 SHIP. WT 12 20 25 55 75 90 150 MODEL NO. WHEEL DIAM. HP CFM SP SHIP. WT 1HBB 1MBC 2BA 2HBF 3BE 3HBC 4BD 4HBD 5BD 9' mi0 12' 15' 18' 21' 24' 27' 30* M 980 H 1165 H 2040 h 2840 1 3725 1H 5235 2 7370 3 . 8760 5 13640 H 44 H W H 44 M 95 115 150 215 255 375 440 650 815 Many other HP and SP Ratings Available. MODEL MOTOR NO. HP PVB-24 PVB-24-A PVB-24-B PVB-30 PVB-30-A PVB-30-B PVB-36 PVB-36-A PVB-36-B PVB-42 PVB-42-A PVB-42-B PVB-48 PVB-48-A H H H H H M H M 1 H 1 1H 1 114 CAPA CITY CFM 4850 5200 5950 7200 8150 9300 12000 13750 15000 15100 16700 18600 19400 21100 FAN RPM 720 780 890 575 650 740 550 630 690 500 550 615 430 470 SHIP. WT 110 115 125 130 140 150 165 175 195 195 215 225 260 270 PEERLESS UTILITY BLOWERS^ Belt drive and direct drive blowers have clockwise rotation, bottom hori zontal discharge. They may be altered as desired. Frames and housings arc-welded. For general exhaust and ventilation with duct system and where circulation through a limited ~flTea is indicated. MODEL NO. MOTOR HP BLOW ER RPM CAPA CITY M' SP 'CFM ' H' SP 0 Vi 1 ' Vi 1 Vi 1M Vi 1H H 1H Vi 1H M 1M H 1M n 2H 2n 22 1725 1150 1750 1150 1750 850 1150 850 1150 690 850 1140 144 250 515 480 870 625 1005 1485 1890 1855 2390 3444 -- -- 420 290 765 -- 830 1420 1795 1190 2005 3080 SHIPWT zT~ 45 55 50 57 100 n 130 142 200 220 244 PEERLESS ARR.\3 BLOWERS Clockwise or counterclockwise rota tion. Blower is easily adaptable to ventilation and exhaust systems. Width is single or double. Motors and drives available. Vibration bases optional. Ball or sleeve construction bearings furnished. WHEEL DIAM. SHAFT DIAM. SHIP. WT SINGLE double WIDTH 2B3 2HB3 3B3 3HB3 4B3 4HB3 5B3 12' 1' 15' 1' 18' Me' 21' iMe' 24' lMe' 27' IMe' 30' 1M' 90 125 155 220 325 430 530 * See Performance Data for Selection of Sixes. 1342 Ait System Equipment Fans and Blowers PROPELLAirDiv.ROBBINS & MYERS, INC. 1947 Clark Boulevard SPRINGFIELD, OHIO VENTILATING SPECIALISTS IN ALL PRINCIPAL CITIES For Dttcts, Walls, Windows. Hoods, Roof Venti lators Propellalr Direct- Connected Fans For use wherever motors may operate within the air stream, from free air to medium and relatively high resistance. A compact, durable design with fan having two to six blades. Sizes: 12 in. to 60 in. Capacities: 1,020 to 85,000 cfm. Type "CD" For Heat, Acids, Alka lies--Fumes, Gases, Dust Belt-Driven Propellalr Tube-Axial Type A complete fan unit in short duct sectioD Iea!?A^or insolation in lines from 20 in. to 60 in. diameter. Type "CS" may be used for severe acid or alkaline condi- f^plosive fumes and gases. Type , for excessive temperatures, cir culates outside air through belt and fan snajt, tubes to keep drive and bearings cool. Capacities: 5,073 to 85,000 cfm. For Heat, Moisture .Fumes, Dust, and Gases Propellair Extended-Shaft Fans This design locates^ motor outside air stream when fan is installed in duct at right angle turn, elbow, "Y," or offset. Simple installation usually can be sup ported by duct without auxiliary brac ing. Drive shaft is enclosed and sealed within steel tube. Sizes: 12 in. to 60 in. Capacities'. 1,020 to 85,000 cfm. Type Power Roof Ventilator Propellalr Sky-Blast Dependable and economical power roof ventilators. Butterfly dampers open wide the instant fan is started, close automatically as fan coasts to a stop, offer virtually zero resistance as heat, fumes, moisture, dust shoot high into air. Rain is prevented from entering by fan when operating. Drainage gutter pre vents leakage when dampers are closed. Sizes: 16 in. to 60 in. Capacities: 2,800 to 79,000 cfm. Propellalr Vaneaxlal Fans Airfoil Principle Entrance Ring Airfoil-Section Blades fan c?mPact, highly efficient pressure innnUSIn^ standard steel drum sections ,"",rporat'g. standard NBMA frame a,,n:i!?, ln. direct drive models. Also m , a"e `.n belt-driven ratings with / u.ts,(ie the air stream. Cast aiufor `U r4oi Propeller and guide vanes Avail a/r,,mPm efficiency and durability, diamli. 111 2A' 30> 36' 48' and 60 `a- modds Vm 3(e!t' ?nd dlrect driven cfm Capacities from 3410 to 85,000 Propellair fans have airfoil-section blades with variations of pitch, curva ture, and thickness to compensate for different lineal speeds of points at vari ous radii. Air movement is uniform over whole fan area. The Propellair curved entrance ring eliminates eddy currents; helps efficient Propellair blades deliver highest pressure and volume. 1343 if?! {: fl; ll i\ V I! . Iiv- P i! - : ; ,V- ,`j. : T' h : : f ;`i,> ]| if" i 'I ;f| ,i ' {i ' I ! -i- f `I 1 I!. )i ;! !? : Reed Unit-Fans, Inc. (D > & iIKftjAyjIi oiuuo rv'_k/u-c.nUice. /Aivo., TxJi /Gvmw HvxfAlaiSASiJilcS, TLioZi. -J\rP*f1t -- 4-:.i REED COMMERCIAL EXHAUST FANS if Reed Two Speed, Reverttide RTS Wind-0-Vent Font, 22, 26 and SO in. tixet. Reed RUF Direct-Drive Exhaust Fant REED wind.o.vent fans For Residential Cooling, Ventilating. Three sizes and corresponding air de livery capacities of RTS model shown cover range of most residential applica tions. High speed cfm ratings range from 3,600 to 6,600. Expansion panels assure accurate fit all openings. Included in Wind-0-Vent line is new 1964 model RDD direct-drive fan in 2-speed, 20 in. size. High speed cfm this model is 2,450. For applications larger than average, Reed offers the RUF Wind-O-Vent, in 36 and 42 in. sizes. This mode! is single speed, reversible, with air capacities of 10,050 and 12,000 cfm. Reed RVU Pack aged Attic Fant fat Vertical or Horizon tal Discharge Instal lations Reed RUF-C Belt-Drive Exhaust Fans For Industrial and Commercial Use. RUF direct-drive sizes are 12, 16 and 20 in., with free air delivery of 1,000,1,700 and 3,700 cfm. - RUF-C belt-drive fans range from 24 to 48 in. sizes, free air delivery ratings from 5,000 to 22,250 cfm. RUF-C motor and blade shafts mounted in ball bearings. Wire guards and automatic wall type exhaust louvers supplied as accessories. REED po:sfr o.VENT FANS # reed packaged attic fans Reed RUF Port 0- Vent Spot Cooling Fant Designed for ease of installation, quiet ness of operation and powerful air delivery. Installed simply with four hanging brackets on rafters. Seven stock sizes from 24 to 48 in. blade diam eter, with corresponding free air cfm ratings of from 5,000 to 18,600. Com pletely automatic shutters. CERTIFIED AIR DELIVERIES Air deliveries are computed in accord ance with ASHVE and PFMA Standard Test Code for Centrifugal and Axial Fans, and conform with U. S. Dept, of Commerce Com'l. Standard CS 178-SI. Complete assembly consists of single speed, reversible fan, with giards each side and haTd rubber caflj* an be moved right up to work, vjj* operation is particularly desirable wn noise factor would interfere with worKefficiency. 36 and 42 in. sizes, . ratings of 13,050 and 15,600. For h& commercial and residential use Port-O-Vent is also supplied in RTS-P 22, 26 and 30 in. sizes. 1344 Air System Equipment Blower Wheels Revcor Carpentersville, Illinois 'Phone: DUNDEE 1290 engineers and manufacturers of single and double blower wheels Two single inlet blower wheels welded together back to back and having a common hub make up the REVCOR DOUBLE INLET BLOWER WHEEL. Any two REVCOR single inlet wheels of the same diameter and of the same or varying widths can be assembled to make the double inlet blower wheel. Heavy gauge backplate and inlet ring assure rigid support for blades and hub. ! Individual blades of correct number, curvature, depth, and blade angle to, deliver the greatest amount of air both : efficiently and quietly. FULL WIDTH blades with a blade tip diameter substantially the same aa the outside diameter of the wheel enable REVCOR BLOWER WHEELS to de liver the MAXIMUM AIR AND PRES SURE FOR THE SPACE DIMEN SIONS REQUIRED. Blade tips projecting through slots in the backplate and ring are bent toward the blade curvature to securely lock the backplate and ring between the bent tip and the shoulder at each end of the blade. Tips may be spot welded for greater strength when required for spe cial severe applications. Cast hubs are attached to the backplate with 4 or 6 rivets. Hubs can be mounted either inside or outside of the wheel. Hubs machined from bar stock are at-; tached to the serrated center hole in the backplate by curling the hub material on to the backplate. The hub material is then pressed into the serrations in the backplate to key the hub to the wheel to prevent loosening. Hubs can be mounted either inside or outside of the wheel. MATERIALS: Steel. Also available in Aluminum, Brass and Stainless Steel. FREE REVCOR CATALOG Containing technical details, diagrams, specifications, and sizes of Revcor Blower Wheels. Write direct to: REVCOR, Dept. R, Carpentersville, Illinois . 1345 Air System Equipment Fans and Blowers Sheldons Engineering Limited G alt--Ontario--Canada FAN MANUFACTURERS FOR MORE THAN 50 YEARS Sales Offices: Haufax-Montreal-Ottawa-ToronTO-Ham3lton-London-Winnipeq-Cai.gary~Edmonton-Vancouveb Specify "SHELDONS" with Confidence Member Canadian Fan Manufacturers' Association. . Silavent Fans Keith Fans Utility Sets ATTENTION AMERICAN ENGINEERS DOING WORK IN CANADA- We invite your inquiries for specifica tions and full information on SHEL DON Fans, Blowers, Exhausters, Heat ing, Ventilating and Air-Conditioning Apparatus, and allied equipment re quired on your Canadian projects. For more than fifty years this Com pany has been well and favorably known in Canada as manufacturers of highquality, air-handling equipment. Our product is readily accepted as "EQUAL" to any other similar apparatus produced on the American Continent. Vertical "Blow-Down" and Hori zontal Unit Heaters, Centrifugal type Heating, Ventilating, Humidifying and Air-Conditioning Units, all embodying fans of Sheldons' own design and manu facture. Forced and Induced Draft Fans, Axial Flow Fans, Chemical Plant Fans, Mine Ventilating Fans, in short, all types of fan apparatus demanded by Canada's fast-expanding industries. Roof Ventilators Air-Conditioners MUl Exhausters Axial Flow Fans Pressure Blowers Write for Catalogs on the types of fans in which yon are interested. 1346 Air System Equipment Fans & Blowers Standard Electric Manufacturing Company West Berlin, 69, New Jersey AIR BOOSTERS Heavy duty for efficient air movement. Square Venturi frame. Balanced Torrington aluminum blades. Heavy arcwelded tubular supports. Quiet, rub ber-mounted motor. Different speeds, 2-speed models. Enclosed or explosion- proof motor. Sizes: 12, 14, 16, 18, 20 and 24 in. For efficient air movement in ducts. For circulation or removal of smoke, dust, heat, fumes. No maintenance. Totally enclosed motor. Terminal box. 3-speed control available. Sizes: 6 to 22 in. Spe cial sizes and types to order. Low cost. Built to Underwriters' Labo ratory specifications. For removing heat, dirt, toxic fumes, smoke. Sealed SKF ball bearings. Aluminum blades. Adjust able motor base. Sizes: 12, 18, 24, 27, 34 in. '' PRESSURE BLOWERS For use in forges, oil and gas furnaces, gas boosting; to remove gas and welding fumes. For all high pressure air moving. Heavy cast aluminum housing. Cast iron if desired. H hp motor. Larger hp rat ings, different speeds and current char acteristics also available. : BELT DRIVE ' EXHAUST FANS Vertical or Horizontal Heavy duty, large volume. Complete change of air quickly. Heavy, rigid, one piece Venturi frame. Arc-welded tubular o?^orts' Rubber mounted motor. Sizes: 4, 30, 36, 42 and 48 in., with SKF ball carings or Randall self-aligning graphue bearings. WINDOW FANS Direct Drive hnm* " venwiation in any room a 24 tn ?a ?^ce-. Portable. Adjustable foi finish ln' win(R>ws. Attractive crean and rpi * 12'16 an(120 in Exhausl nU reversible. Also Belt Drive. VOLUME BLOWERS For maximum efficiency ventilation, coal blowers, dust removal and other air moving applications. Heavy cast alu minum housing. Non-vibrating, rubbermounted motor. Torrington Varified Airoter Blower Wheel. Available with Ho, H> H hp motors. SEND FOR CATALOG COVERING MANY OTHER TYPES OF FANS AND BLOWERS. 1347: The Torrington Mfg. Co. Air System Equipment Fans and Blowers Blower Wheels The Torrington Manufacturing Co. .Slinger Rings" for Assembled Fans-- 50 Franklin Street, Torrington, Conn. A rolled ring, L-shaped in cross-section, Western Division: Van Nuts, Calteobnia. In Canada: TMCo., Ltd., Oakville, Ontabio Manufacturers of Blower Wheels and Propeller Type Fan Blades. with solidly welded joint. Designed to adapt all popular sizes of assembled Airistocrat fan blades for application as. I? ! condenser fans on room air conditioners. A1MPSB& \jBIourtrWheelt Design allows considerable flexibility as to diameter, location of ring on periphery of blade, etc., without expensive tooling. "Slinger Bings" for Assembled Fans "E" Series AIRISTOCRAT Fan Blades--Outstandingly high efficiency is the chief characteristic of this fan blade. It delivers more air for any given horse power. Size for size it looks bigger, more powerful. In impartial tests, ten competitive fan blades were recently compared with "E" Series blades of the proper diameter and pitch. In every case, air delivery was sharply increased. Within the same space limitations and with the same power, the "E" blade delivered as much as 28 per cent more air. Convincing proof of the superior per formance of this fan may be found in the NEMA and NAFM tables prepared as a guide to selection. Thecatalogcontaining these tables and specifications will be mailed upon^request. & New "LU" Series One-Piece- Airisto crat Fan Blades--An extremely quiet and very efficient one-piece fan designed especially for refrigeration and air con ditioning applications. This quality product is hand-set to assure accurate forming and alignment. Made of alumi num, pierced for all unit-bearing motors. Sizes: 7%, 8% and 10 in. diameters. Airotor Blower Wheel--Single Width--Single Inlet Patents 2,2Slfi62; 2,272,695 Des. 126,048 "One-Piece" Airistocrat Fan Blades-- Exceptionally rigid models blanked from one piece of metal. Made in both steel and aluminum. Sizes 3 in., 4, 4^, 5, 5}$, 6, 6J^, 8, 9, 10, 12 and 16 in. diam eters, all four blades; also 5^, 7, 8, 9, 10 in. 5-blade. Available in the follow ing finishes: 1. Plain. 2. Lacquered. 3. Zinc plated (steel only). Airotor Blower Wheel Double Inlet--Spider End Plates Specifications: Three-blade models in 10 in., 12, 14, 16, 18 and 20 in. djameters; four-blade models 8 in., 10,12,14,16,18, 20.22 and 24 in. diameters. Five pitches.iii most sizes. Aluminum blades, steel spider and hub. Standard finishes. f. Torrington Airotor Blower Wheels are light, sturdy and inexpensive--incor porate new principles of design and con struction, which insure rigidity and con centricity. Single Width--Single Inlet wheel is of simple four-piece construc tion-- No rivets or welds are used; Neoprene Hubs for Shaded Pole motors concentric rib serving as backing for blade strip is formed at same time as --designed to minimize the transmission hub socket, insuring trueness of wheel. and amplification of motor noises by the fan blade. These hubs are currently available in 34, /4b, %, He, 34 >n- d'aro` eters for Torrington propeller fans up to and including 12 in. diameters. Rigid radial ribs prevent deflection by thrust. Three thicknesses of metal in nms make for maximum strength. Excellent for many heating and venti lating uses. Manufactured in both aluminum and steel in 1% in., 2,3,3%, 4, "One Piece" Airistocrat Fan AIRISTOCRAT "M" Series Attic Fan Blades--Three outstanding features of this new design are: (1) Extremely high efficiency, which gives ipaximum cfm per 6 '7,8^,9 and 10$ in. diam eters. Clockwise or counterclockwise rotation. Same sizes available in DA l>pe double width, double inlet wheels. i } horsepower; (2) knockdown construction which drastically lowers shipping costs, (3) quiet operation--a point of major interest to the consumer. This all steel four-blade fan is manu factured for attic use exclusively, m TM 30,36,42 an'd 48 in. diameters, in 40 deg **uagion Airotor Blower Wheel-- Rouble Inlet--Spider End Plates. Has acies .punched and formed in a single r,,P .nSidly held by flanged single piece u rings. Hubs are rigidly mounted pe?in*- . Wheels of 2M in., 3^ in., pitch only. nr^ and *n- diameter are available at Now "L U" Series One-piece Airistocral Pan Blades Seeve^edAdditi0nal sizes now being 1348 1349 4-Blade Airistocrat Attic Fan "li" Series Air System Equipment Fans and Blowers CLIPPER Trade-Wind Motorfans, Inc, 5725 So. Main St. - Los Angeles 37, Calif. Representatives In All Principal Cities. Carried In Stock By Many Electrical Jobbers TRADE-WIND CLIPPER CEILING VENTILATORS Cutaway view of Model 2601 show* double blowers used in Ms unit. THE TRADE-WIND CLIPPER BLOWER is a small capacity centrifugal blower, primarily used for exhaust ap- lication. While used extensively for ome kitchen ventilation, it is adaptable for other applications, such as in school toilets, therapy and treatment rooms in hospitals, dental laboratories, ticket booths, offices and x-ray and photo* graphic dark rooms. This is a "unit package" assembly, com plete with ceiling grille and necessary electrical connections. It is Underwrit ers* approved and listed. It carries a (pro-rata) five year guarantee. The in stallation requires only the application of a discharge duct of the same dimension as the outlet collar and the optional addi tion of an automatic shutter for the end of the duct. The assembly is inherently quiet and is installed rigidly in the structure without need for resilient mountings or flexible duct connections. The blower is nor mally quiet at its maximum speed. The motor and wheel unit is removed easily without tools through the ceiling inlet opening. The patented construction of the Clipper entirely isolates the motor from the air stream. This special fea ture keeps the motor free from contam inated air, adding to its service life. LEFT: Blower unit and grille in all Trade-Wind models are easily removed without tools. Unit shown is Model 1501. RIGHT: Model 8501 installs in a cabinet over the stove. Inlets, equipped with washable filters, are pro vided in base of unit and at ceiling and fold-under hood is optional. Selection Chart and Specifications TRADE-WIND CLIPPER VENTILATORS--115 Volt, 60 Cycles, A.C. Cat No. 1201 Clipper 1501 Clipper 2501 Clipper 3501 Super Clipper Description Horizontal discharge com plete with grille. Interchangeable horizontal or vertical discharge, complete with grille. Interchangeable horizontal or vertical discharge complete with grille, 2-epeed motor & switch. Cabinet Installation Includes housing, 2 filters, 2-speed motor and switch; stainless steel hood optional. J.ype Blower Single Wheel Two Wheels Two Wheels Two Wheels Net Air CFM 100 Recoznm. Max. Room Size Cu Ft Bathrooms Only 300 1000 425 2000 550 3000 Duct Size 4' Round 10**3*' Motor Watts 60 90 10*x3J* ' 145 13*x4' 185 ' 1350 Air System Equipment Blowers Viking Air Conditioning Corp. Division of The National Radiator. Company . 5601 Walworth Avenue, Cleveland 2, Ohio Customized Mass-produced Blowers for Furnace and Air Conditioner - Manufacturers Bottom Horizontal Blowers Top Horizontal Blowers These photos show standard blower both Viking Univoil bearings which motor positions, however, motor can be can be revolved 360 to the easiest posi mounted on the blower where you tion -for oiling and locked there per specify. Blower outlet can be located in manently or grease bearings for blowers any position you require. Viking offers placed in inaccessible locations. Upblast Blowers DowrMast Blowers Write Viking for this 16 page booklet "Viking Blower As semblies" which serves as a source of information and work book for specifying the sample model blower assembly you need for testing with your furnace design. Contents of Work Book Air Selector Table for determining CFM Blower Capacity Table Speed Ranges of Variable Pitch Pulleys Dimensions for Blowers in different positions Motor location grid--9 in., 11 in., 13 in. blowers (includes acetate template for simplifying paper work on motor loca tion) Belt sizes for standard and non-standard motor positions Effect of side and rear wall clearance on blower performance Effect of blower outlet and Furnace drum clearance on blower efficiency 1351 i - Air System Equipment Fans and biom jp Western Blower Company Aitilanulni Affinn anunufl xPulUnnilif> i1wOAuA iAx!irj.pnuni*wt W'* wn ijrj-,Sw*o'fatvf*f*lwa A Wn oags*jlii4tlfifi+gOivTuJ Sales Offices in the Principal Cities West oi Rocfcy Mountains Turbine Multiblade Fans--forward curved blade, Type TR, or backward curved blade, Type "S," fans for heating, ventilating, mechanical draft, etc. Bulletins No. SO and SI. . .. Mill. Exhausters--single or double for material conveying exhaust systems, direct connected or V-belt driven. Bulletin No. S2-S. ' Pulley Driven Utility Sets--V-belt driven, slow speed, quiet operating, for general utility duct ventilating systems. Bulletin No. St. ri . . RB Volume And Pressure Fans Western Unit Heaters Centrifugal Exhaust Fans RB Volume And Pressure Fans--radial blade type either direct connected or V-belt driven for ventilating and conveying applications. Bulletin No. 39. .' Western Unit Heaters--vertical or horizontal, for general heating and drying appli- cations. Bulletin No. 68. Centrifugal Exhaust Fans Series 59--for general exhaust systems. Complete packaged units. Bulletin No. 69. Air Washers Volume Heaters Spirovane Propeller Fans Air Washers--for cleaning, cooling, humidifying and.dehumidifying. Bulletin No- Volume Heaters--with one or more centrifugal fans for heating, ventilating and air conditioning. Available in vertical or horizontal cabinet units. Bulletin No. 44- Spirovane Propeller Fans--furnished either direct connected or V-belt driven U> commercial or industrial ventilation. Bulletin No. SO. ' ,. Olympic Heat Exchangers--Converters, Side Arm Heaters, Immersion Heaters, y1 Heaters, and Condensate Coolers. Bulletins as listed above furnished upon request. 1352 Air System Equipment * Westinghouse Electric Corporation Siurievani Division Air Conditioning, Heating, Ventilating, Dust Control and Fume Removal Equipment, Electronic Air Cleaners, Compressors, Mechanical Draft Equipment Hyde Park offices in Principal cities Boston 36, Mass. AIR HANDLING PRODUCTS Centrifugal Fans--General purpose and Heavy Duty centrifugal fans are highly effective in both commercial and indus trial service. Capacities up to 480,000 cfm and pressures up to 32 in. w.g. Axial Flow Fans--Axiflo fans are designed to operate against resistance, are avail able for either vertical or horizontal air flow. Widely used in industrial heating, ventilating and fume removal. Ventilating Sets--Series 900: direct, con nected units for maximum efficiency at popular motor speeds. Manufactured in six sizes up to 3200 cfm. Series 1000: com pact V-Belt driven units for large capac ity and quiet operation. Twelve sizes up to 14,400 cfm. Air Handling Units--For year-round air conditioning, also available for heating and ventilating or ventilating only. They feature sectional construction, various types of coils, and accessories to give combinations to suit the application and space. Capacities to 23,000 cfm. HEAT TRANSFER PRODUCTS Heat Transfer Surfaces--Sturtevant cooling and heating coils are available for Freon, chilled or not water and steam, bteaca coils are of standard, heavy duty steam, and steam-distributing types, Air Blenders--For both winter and sum mer conditioning of individual rooms, air blenders mix conditioned air from a central system with recirculated air. Surface Dehumidifiers--For central plant air conditioning, these sprayed coil units are available with chilled water or irect expansion coils. Capacities to 115 tons of refrigeration and 45,000 cfm. Silentvane Centrifugal Fan Design 10 Direct-Connected Ventilating Set Air Handling Unit Type AH Air Blender Axiflo Fan Design S A V-Belt Ventilating Set Direct Expansion Type BA Evaporator Coil Industrial Heaters--For heating of man airing areas, warehouses, garage hi -i J>eneral industrial and commerch uudings. Also for continuous duty heal DaL>1D industrial processes and steel P Per and rubber manufacturing. Capac pi8 2,500,000 Btuh and 25,000 cfnr at Fan Heaters--Available fo tinn ' water and gas-fired applies fairhorizontal and downblast model! Btuh''1163 range from 20>000 t0 400'00 DownUast Speedheater 1353 Horisonlal Speedheater St- Air System Equipment Motors U.s. electrical motors inc. Pacific Plant: Box 2058, Los Angeles 54, Calif. Atlantic Plant: Milford Conn. Atlanta 3, Ga. Bakersfield, Calif. Boston 16, Mass. Buffalo 21, N. Y. Chicago 8, III. Cincinnati 37, Ohio Cleveland 14, Ohio Dallas 6, Tex. Dayton 2, Ohio Detroit 4, Mich. Fresno 1, CiuF.. Fort Worth 10, Tex. Houston 20, Tex. Indianapolis 5, Ind. Knoxville, Tenn. Lubbock., Tex. '' Memphis 1, Tenn. Milwaukee 3, Wise. Newark 4, N. J. New York 6, N..Y* Philadelphia 2, Pa. Phoenix, Ariz. Pittsburgh 22, Pa. Sacramento 14, Caut. St. Paul 4, Minn. San Francisco 7, Calif. San Jose 10, Camp, Seattle 4, Wash. U. S. Motors manufactures a complete line of motors applicable to heating, ven tilating, and air conditioning services, including Standard Uniclosed, Varidrive, Syncrogear, and Totally-Enclosed (Explosion-Proof) types. Respective Bulletins describing each type, accompanied by engineering data will be supplied Upon re quest. Please communicate with our nearest office or local dealer. U. S. UNICLOSED MOTOR Completely housed and armored against dirt and moisture. Distinctive louvered vents facilitate ventilation and deflect drippings. Streamlined. Available in. open, splashproof, and bracket types. Horizontal and vertical settings. Ratings from to 250 hp. Request Bulletin 1594. U. S. VARIDRIVE MOTOR Any rpm by simple dial control in speed ratios up to 10:1. 2 to 10,000 rpm. % to 50 hp. Local and remote controls. Instant speed change. Request Bulletin 1797. U. S. SYNCROGEAR MOTOR Internally-geared. Completely enclosed gear compartment. Compact--saves space. Eliminates external gear box. 10 to 10,000 rpm. K to 30 hp. Request Bulletin 1498. ,U. S. RIGHT-ANGLE WORM GEAR Syncrogear motor with cantilever design to maintain perfect alignment of motor bearings ana gearing. 20 to 155 rpm. 7* to 3 hp. Request Bulletin 1650. U. S. TOTALLY-ENCLOSED MOTOR Explosion-proof. Meets Underwriters* specifications for dangerous, damp and dusty locations. With or without fan. % to 75 hp. Request Bulletin 1784. 1354 U. S. MOTORS FEATURES: Asbestos-protected windings Normalized castings . Lubriflushed bearings Streamlined design Hi-draft ventilation Balanced rotor .* J. ` Air System Equipment Motors WAGNER MOTORS for Heating, Ventilating and Air Conditioning Equipment Type TZ--Permanent Split-Capacitor Totally enclosed non-ventilated, 55 C, with sleeve bearings and resilient base or rubber rings for mounting. Ratings 1/20 to 3/4 hp, constant speed, two speed or adjustable speed, standard voltages and frequencies. Split-phase, squirrel-cage and direct cur rent 55 C, totally enclosed non-ventilated fan-duty motors are also available. SINGLE-PHASE MOTORS POLYPHASE SQUIRREL-CAGE MOTORS Wagner open-type 40 C general purpose single-phase motors are built in standard models with sleeve or ball bearings and rigid bases. Resilient bases are avail able on fractional hp and small integralboreepower ratings, and face and flange type endplates can be furnished to meet -specific requirements. Thermal proteci?58ih_cpa.n ^ supplle4 on ratings through Typ^ RA--Repulsion-Start Induction Wagner open-type 40 C single-speed poly phase squirrel-cage motors are built with sleeve or ball bearings and rigid bases. Multispeed motors, vertical and flange mounted motors, and splash-proof and totally enclosed motors are also avail able. Type RP-1--Normal Torque Normal Slip Ratings 1/6 to 400 hp, 3 or 2 phase, all standard voltages and frequencies. Righ starting torque, low starting cur- re K to 15 hp, all standard voltages ana frequencies. ` *rpe rui.--Lapacitor-Start Induction Type RP-5--High Torque Normal Slip Ratings 13^ to 200 hp, 3 or 2.phase, all standard voltages and frequencies. Righ starting torque, normal starting urrent. 3^ to 3 hp, all standard volt ages and frequencies. ?^?e TM Shaded-pole, low startin !i `0r sbaR mounted propellor fan ptw.1 dfaw air oyer the motor. Totall rn sed non-ventilated, no temperatur 0r *.n?> Wltb sleeve bearings, round fram l/}SgIi /?resilient base* Ratings 1/12* vol? W0' 1/30 and */20 hp, 115 or 23 a? nrA60(Or,?0 cycles- Three-speed re fied c?n^ro^ers.can be supplied if spec] fan.H,,* COraPanion line of direct curren uty motors is also available. Rst.i Part-Winding Increment Type Motorand-Starter Combination A low cost combination of a squirrel-cage motor wound with two parallel star cir cuits and a magnetically or manually operated two step increment type starter, which limits the inrush of current at starting. Available with normal or high torque open or enclosed motors. Write For These Bulletins MU-185--Describes and illustrates all types of Wagner motors. . MU-40--Lists part numbers and prices of Wagner Motor repair parts. 1355 Air System Equipment * E. H. Sheldon Equipment Company Muskegon, Michigan' SHELDON INDUCTION FUME HOODS Manufacturers of Laboratory Equipment for Schools, Industry, and Hospitals. SHELDON'S induction hoods are designed for use in air-conditioned laboratories or in any situation where it is necessary to conserve room air. By injecting regulated volumes of "out door" air into the working areas of the hood to supplement the primary airflow from the laboratory, the following con trolled conditions may be achieved: 1. Sufficient volume of air passes through the working areas of the hood at the face velocity required to insure com plete evacuation of fumes from the system. The exhaust system of the Sheldon induction-type hood handles the same volume of air that the exhaust system of the conventional hood handles at a face velocity of 70-80 linear feet per minute. 2. At the same time, air movement from the room into the hood has a low enough velocity to minimize turbu lence within the hood and assure quiet operation, and to prevent objection able drafts in the work area, and ex cessive drain on the heating, cooling, and air-conditioning systems of the' room: The difference between the ex haust volume and the volume of intake from the room is provided by adjust ing the supplementary-air supply. 3. Sufficient volume of air flows into the hood from the room to carry generated fumes into the fast-moving, high- volume evacuation air currents, and also to insure optimum laboratory air changes. ' If air movement from adjacent parts of the building to the laboratory is desired, a condition of negative pressure in the laboratory may be induced by lowering the supply-fan capacity or increasing the exhaust-fan capacity. Also, even if the front sash is closed, the hood will purge of fumes because a definite part of the exhaust capacity is still being supplied mechanically and passes through the hood. . Except for minimum filter requirements, provided for in the hood design, supple mentary air seldom needs to be treated, since it does not enter the room. The following table gives the velocity, velocity pressure and total entrance loss for both exhaust and supply for various lengths of hoods with duct sizes as shown in diagrams betew. These values are for volumes as shown. These values are based on exhaust fan capacity capable of producing a face velocity of 75 Ifm with only the exhaust fan operating and with a supply fan capable of introducing % the exhaust capacity and producing 8 face velocity of 25 lfm with both fans operating. 1356 Air System Equipment E. H. Sheldon Equipment Company Muskegon, Michigan SHELDON INDUCTION FUME HOODS Manufacturers of Laboratory Equipment for Schools, Industry, and Hospitals. EXHAUST @ 75 L.F.M. face Vel. SUPPLY @ % of exhaust Hood Length 3' 4' 5' 6' V 8' cfm 487 690 900 1087 1275 1500 Vel 1800 2000 2000 1900 2000 2000 VP 0.20 0.25 0.25 0.23 0.25 0.25 Entrance Loss 0.30 0.37 0.37 0.42 0.44 0.44 cfm 324 460 600 724 850 1000 Vel 1900 1800 1650 1400 1600 1800 VP 0.23 0.20 0.17 0.13 0.16 0.20 _ Entrance . Loss 0.34 0.30 0.26 0.20 0.24 0.30 * Total negative static developed by the hood. The conversion factor to obtain entrance loss from velocity pressure is 1.5 for 3 ft, 4 ft and 5 ft hoods, and 1.75 for 6 ft, * 7 ft and 8 ft hoods. ** Total positive static developed by the hood. The conversion factor for all hoods for the supply air static is 1.5. These statics should be added to the duct resist ances when computing fan sizes. S' HOOD ' HOOD 5' HOOD 7SUPPLY " DM. 7SUPPLY " OlA. 7SUPPLY " DIA. 10TOAUJI ~ DIA. 6' HOOD 11EXHAUST " DIA. 7* HOOD 17EXHAUST " DIA. ' HOOD The duct stubs are located on the top of Ihe hoods as shown. The supply air can enter from below when building condi tions require such arrangement. The values given in the table for various engths of hood are for average condi tions. ((lnce the hoods use a definite voli conditioned" air, their requiri 8 uld be considered very early work of designing and specifying heating and/or conditioning plants. Sheldon engineers welcome new problems arising out of recent production and development programs. A laboratory at Muskegon is maintained for this purpose. A list of satisfied users of a wide variety of industrial installations is available upon request. Contact the Muskegon office for the field engineer nearest you. .. 1357 Allen Ventilator Division Production Planning Company Rochester, Michigan Representatives in Principal Cities See Sweet's Catalog for Further Details Write to Factory for Catalog i HIGH EFFICIENCY ROOF FAN Allen Type "H" Roof Fan is designed as a general purpose, power driven exhaust unit for either new construction or re placement service. It features rugged construction, low power consumption, ease of installation, large air removal capacity. Available in a wide range of capacities (750 to 45,000 cfm) and in three series: Standard with belt drive; Direct Drive, and Remote Drive, for use where air is laden with heat, fumes, vapor or dust. 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' building openings. Fabricated of prime zinc- coated iron sheet, welded construction , throughout. Automatic wing dampdfs open with air blast, close weathertight when not operating. Available with Direct Drive, with motor readily acces sible, of Remote Drive, with motor in outside housing and enclosed' V-belt drive. . i \ t STAXAUSTER FAN Allen Staxauster is a simple, compact, sturdy unit that can be used to convert all types of roof ventilators into power ful exhaust or air supply units. It is available in many sizes with either Direct Drive or Remote Drive for handling corrosives and/or high temperature air. \ TURBINE VENTILATOR Allen Type "C" Turbine Ventilator is wind driven and economically removes heated air, fumes and dust. It is made of heavy-gage coated iron or of special non-ferrous metals, and is easy to instal and maintain. Many thousands of Tyi* "C" Turbines are in use in industry. 1358 ' Air System Equipment Air Vent. THE G. C. BREIDERT CO. 3129 San Fernando Road, Los Angeles 65, Calif. Representatives Located in Principal Cities of the U. S. BREIDERT AIR-X-HAUSTERS FOR ROOF VENTILATING, VENT FLUES & CHIMNEY TOPS SUPERIOR PERFORMANCE PROVED BY CERTIFIED* RATINGS BASED ON DIRECTIONAL WIND TESTS. Breidert Air-X-Hausters provide safe, sure ventilation no matter which way the wind blows. Breidert Air-X-Hausters pioneered with published certified capacity ratings based on tests* made with wind blowing in all directions as shown at right. Only such, tests can guarantee the capacities a ventilator will deliver under actual oper ating conditions. No matter which way the wind blows, barring interior negative pressures, the Breidert provides safe, sure ventilation ... on roofs, vent flues, chimney-tops. Stationary, no moving Vertical Down Old Method of Testing . ^r0 Q Breidert Method of Testing w-1?8! not,kmg to jam or get out of order. Widely used on all types of factories, commercial buildings and residences. in tt/raultn ** nee<^ with Breidert Air-X-Hausters ira 8eason to stop min leakage or down/ . A o danger of a Breidert blowing off the roof. Patent Ho. BS694S ELASTIC YARDSTICKS DON'T MAKE SENSE! Capacity ratings of most ventilators are based on horizontal wind tests only. In actual use, ventilators must perform with winds blowing at any angle. In many cases of ventilators without certi fied ratings, performance does not equal ratings claimed. Capacities of Breidert ventilators have been conclusively established by Pitts burgh Testing Laboratories. This assures unbiased, factual ratings to accurately establish performance in actual use under all types of conditions, in deter mining how to best meet, your ventilating requirements. Write for Free Engineering Data Book. . . containing de tailed specifications and installation data, certified capacity ratings, etc. Address Dept. HVD. 1359 '.i ih:] !ii i i' m, *t* !;-! jv n ; 51 l ;! % . ;r t ii '! ` !* i i ' : f :! Air System Equipment R< ventnaoi^f Air System Equipment The Gallaher Company 4108 Dodge Street, Omaha 3, Nebraska Representatives in Principal Cities of USA and in Canada by Canada Fans Ltd. Manufacturers of AIR-VAN and AIR-MAX Power Roof Exhausters Hirschman-Pohle Co., Inc. 200 Lent Ave. . . . LeRov, N. Y. Sales Representatives in Principal Cities jam ussm The STATICK Power ventilator has been especially designed as pressure.exhauster for roof mounting, and its use conserves much valuable space within the building in addition to reducing installation costs without sacrifice of efficiency. It uses the con ( ventional type of backward curved blade fan wheel that will not overload motor at any static pressure, and it provides a factor of safety for possible later changes in duct system. Cont removobte ' for service Series 1, 2, 3, 4, AIR-VAN Series 5 AIR-VAN Belt Drive Direct Drive Capacities 1,000 to 65,000 cfm. Static Capacities 150-11,700 cfm. Static Pres Pressures to 4 in. The only belt driven sure to 4 in. Low installed silhouette power roof exhauster with guaranteed design with motor out of airstream for. high static pressures and air volumes. protection against fumes. ' Exclusive - Motor out of airstream. Patented scroll Gallaher scroll effect design. Shipped effect design. Shipped as complete pack- as complete package ready for installa age including base. Does not require tion. Series 1, 2, and 3 have forwardly extra height for unobstructed discharge. curved, wheels with blades at varying Extremely heavy construction. Certified angles. Series 4 has backwardly curved ratings by an independent laboratory. non-over-loading wheels. Choice. of Weatherproof under extreme conditions. wheels'allows buyer to tailor-make unit and select exact capacity desired. Rat ings are certified by an independent laboratory. . AIR-MAX Downblast Model C Capacities 1,000 to 44,000 cfm. Static Pressures to % in., and more on special order. Designed to handle relatively dry air at minimum horsepower. Low sil houette. Economical direct connection to duct system without field assembly. Fully blackout. Certified Ratings. Can be furnished for summer or winter supply as well as exhaust. Propellers incorporate latest features in air foil design--four or six blades. Can be replaced without buying new wheel. AIR-MAX Upblast Model CU . Capacities 1,000 to 44,000 cfm. Static Pressures to ^ in. and more on special order. Designed for upward discharge. Special clam shell type dampers give weatherproof protection when units are not in operation. Units have low bjIhouette characteristics of all Gallaher units. Sturdy construction throughout' Damper stops prevent locking in the open position. Units can be supplied in Aluminum, Copper, Monel, Stainless Steel, and in any resistant finish. For complete catalog information including certified rating tables, and all pertinent selection and installation data, wi ite The Gallaher Company or contact its representatives. ^360 / switch for service ^ Spring & Rubber Vibrolion Absorbers Louver Oernper Corner Reinforcing The low speeds possible with this type of fan, plus solid construction of the entire unit and the vibration dampeners used, permit the quiet operation so desirable for many types of installations. Because of the flexibility of belt drives, each size unit has a wide range of capacities at static pressures within the limits of the motor horse power. Fan wheels are both statically and dynamically balanced by the latest and most modem equipment available. Standard capacity tables or suggestions to meet your requirements available on request. The Type "LA" STATICK Power ventilator shown above permits room for dampers as an integral part of the ventilator with means of access to the dampers and their operators, also permits of fitting to other than a standard square curb where , 'building construction makes such odd shapes desirable or necessary. The entire fan and motor assembly is mounted on rugged welded steel angle frame by means of spring and rubber vibration absorbers. Motors used are of standard manufacture designed for vertical operation, ball-bearing, continuous duty. Our standard design is such that the motor compartment is permitted to receive free ventilation for motor cooling purposes, but this compartment can be isolated entirely from the exhausted air where injurious fumes are being exhausted. The exhaust cowl itself has been designed to permit unrestricted air outlet and to present a pleasing appearance. Either the top cone or the entire cowl are removable for servicing. These units can be furnished of galvanized steel, aluminum, copper or other avail able metals, with or without dampers, as desired. Dampers included can be of the self-acting type or for chain, electric or pneumatic control. The Hirschman Type "F" Electric Ventilator (not shown) use3 a highly efficient Propeller type of fan designed to exhaust free air or at the lower static pressures, also permitting high gravity exhaust during periods when fan operation is considered unnecessary. This unit can be furnished with any type or size of base connection desired, with or Without any type of clamper for any type of control. For extreme heat conditions r where injurious fumes are to be exhausted, the motor can be isolated from the Path of the exhausted air by nnr Isolated motor section, either single or double shell. Motors used are of standard manufacture designed for vertical operation, fully cnclosed, ball-bearing, continuous duty. Data for any capacity will be gladly furnished on application. We also manufacture a complete line of rotary and stationary gravity ventilators or any .type of application. 1361 '* i:; ; *;: *{) Iron Lung Ventilator Company 5407 Prospect Avenue Cleveland 3, Ohio Manufacturers of IRON LUNG Roof Ventilators and Air Intake Units High Velocity Discharge exhausts pol luted air so high above the roof that .impurities cannot return to building through open doors and windows. All IRON LUNG roof ventilators are equipped with Airfoil Propeller Axial Flow Fails having air delivery ratings certified in accordance with the Stand ard Test Code for Axial Fans endorsed by the PFMA and the ASHVJE. Without cost or obligation our experi enced engineers will cooperate in plan ning efficient ventilation for any type or size of industrial building. Write for Catalog listing all sizes with complete specifications. Data sheet will be in cluded to make it convenient to explain a specific ventilating problem. "IRON LUNG Chassis, Assembled "Cut-a-way View of IRON LUNG" Left: IRON LUNG chassis, a sturdy , all-welded unit that supports-the fan, fan ring, and motor--one of the really^, great improvements to electrically op* erated roof ventilators. Adds strength to the entire unit--absorbs vibrations.. Cat. No. 300 340 341 348 351 358 370 376 383 ` Size 20* 24' 24" 30* 30* 36' , 42' 48' 60' IRON LUNG RATINGS RATING CFM . HP RPM 110/220 Volt, 1 Phase, 60 Cycle 3720 M 1725 5200 M 1725 220/440 (or 550) Volt. 3 Phase. 60 Cycle 6510 >4 1725 8880 >4 1725 10900 1 1725 13500 1 1725 21150 2 1140 2SS00 3 1140 40000 3 1140 Approx. Net Wt. 175 lbs. 209 lbs. 233 lbs. 288 lbs300 lbs. 390 lbs. 613 lbs. 773 lbs. 875 lbs. ApproxShoe. Wt. 250 lbs. 316 lbs. 356 lbs. 455 lbs. 465 lbs. 565 lbs. 808 lbs. 983 lbs. 1175 lbs. _ E Power Ventilators Air System Equipment Air Intakes Muckle Manufacturing Co. 666 Belford Road Owatonna, Minn. Sales Engineering Representatives in Principal Cities MUCKLE VENTS are propeller driven, axial flow, roof mounted power ventila tors; designed with the motor out of the air stream to be used where especially heavy concentrations of water vapor, toxic or corrosive gases and other harm ful contaminants are present. These units are very efficient at low static pres sures. A11 fan blades are certified under NAFM test code ratings. MUCKLE VENTS come as a complete Packaged unit, ready, to install and can e installed equally well on old buildings or incorporated into new structures. They are designed for use on industrial, commercial and institutional buildings. These units are available in 15 sizes varying from 254 cfm to 10280 cfm with some sizes turning at slow speed for quieter operation. These ventilators are powered with a standard make, continuous duty, full ball bearing, completely enclosed electric motor of the permanent split capacitor type so that 2 and 4 speed switches can be used. Explosion proof motors are available. The base and throat of MUCKLE VENTS are made from 14 and 16 gage steel. The storm bands and cones are made from 18 and 20 gage steel. The parts are hot dipped galvanized after fabrication to insure complete coverage of all sheared edges and welded seams and joints. The motors are directly connected to the propeller--no belts to wear out, tighten or replace. MUCKLE VENTS are designed completely weather proof--rain can not enter the flue past the storm band. Automatic or motor driven back draft dampers are available with or without fuseable fire links. Corro sion resistant coatings can be supplied on order. NEW MUCKLE LO-SIL VENTILATORS ftf for schools, hospitals libraries, churches, restaurants, and commercial buildings. These units present a low silhouette in accordance with the latest trend in architecture. Ine LO-SIL ventilators are available in ^1 capacity sizes varying from 225 cfm 17,600 cfm, static pressures to % in. jiome units operate at slow speed to ef- quiet performance. Cut away photo shows placement of motor which Counted on special vibration separators. Jl od,s binged and secured by two heavy uty draw buckles which makes inspecJon easy from the roof. Material is fieav>- gage steel, electric welded and Oih et* wi_tb two coats of special paint. coatings can be supplied on order. - otors are totally enclosed, full ball aring available for single or three ` ase.current- Single phase motors are lion C1pr type for variable speed opera- n, hxplosion proof motors available on special orders ^RITE for FREE data book--contains specifications, physical sizes, CAPACITY RATINGS AND INSTALLATION DATA. 1363 Air System Equipment Roof VentDatcrs Penn Ventilator Company Goodman above Allegheny Ave. Philadelphia 40; Penna, Representatives and distributors in principal cities. Roof ventilators and accessory products for PUBLIC, COMMERCIAL AND INDUSTRIAL BUILDINGS Air System Equipment Air Vents and Roof Ventilators The Swartwout Company 18511 Euclid Avenue. Representatives in Principal Cities Cleveland 12. Ohio duct exhaust ventilator GRAVITY ROOF VENTILATORS PENN POWER Powerful, positive air mover--efficient propeller fans in dual purpose housing-- gravity exhaust through syphonage ac tion when fan is not operating. PENN DYNAFAN Quiet, steady exhaust against system re sistances. Centrifugal fans in fourteen sizes belt-driven at speeds to fill maoy capacity requirements. The Airlift is a centrifugal fan unit for duct exhaust, against static pressure. Operates at very low noise levels. Fan has backwardly curved blades completely non-overloading; bottom of wheel flared to form throat overlapping inlet increases efficiency, avoids turbulence. 14 sizes, 138 capacity variations. WEATHERPROOF LOUVERS Swartwout Airmover Compact multiple opening type featur ing very short air travel, built in units 10 ft x 7 ft, 6 in. x 32 in. high; 30 sq ft of opening per unit. Used as single units, or single or multiple width runs. Unusual large scale ventilation results possible by roof coverage such as illustrated. Can be adapted to any type of roof. Insert shows "open roof" effect. HI-EX Straight thru--high velocity--vertical discharge air exhausters--streamlined housings. Certified capacities from 2,400 cfm to 60,000 cfm. PENN AIRETTE Efficient fans housed in easily installed, modern and inconspicuous roof mounted housings. Certified capacities from9,0W cfm to 40,000 cfm. FOR MORE THAN TWENTY-FIVE YEARS THE BUILDERS ROOFTOP LINE ' Manufacturers of roof ventilators PROPELLER FAN, CENTRIFUGAL, STATIONARY, ROTARY RIDGE See Sweets Architectural or Engineering File or write direct for catalog data- Trade Marks Registered 1364 Swartwout Airlouvcrs arc fabricated to 7i3y-*n :l.xv*de selection of sizes up to 44 in. high by 48 in. wide per unit, rovide adjustable or fixed weather proof louver equipment to fit wall openng desired. Large openings fitted with of units of equal size for best ap pearance. Optional operating methods; PUona) anchoring methods. Swartwout-Dexter Heat Valve Continuous opening natural draft venti lator particularly effective for ridge of peaked roof, saw-tooth construction or skylights; adaptable to flat or slant roofs. Made in throat opening sizes 4, 6, 9, 12, 15,18,24,30,36 and 42 in. Ten foot units. Adjustable damper. Weatherproof. OTHER SWARTWOUT ROOF VENTILATOR TYPES powered and powered powered powered See Sweets Architectural, Engineering, and Industrial Construction Files. 1365 i Air System Equipment vSi Western Engineering & Mfg. Co. ESTABLISHED 4112 Ocean Park Ave. Venice, Calif. PRODUCTS HIGH EFFICIENCY ROOF VENTILATORS . Western Rotary A rotary mechanism actuated by the re action and impulse of air currents under pressure. The high, comparatively smooth exhaust level of this unit is achieved through centrifugal force and "Flywheel" effect. Aeronautical lab tested. Independent bearing suspension eliminates outside braces. Bearings guaranteed for life. Storm and rainproof. Sizes: 6 in. to 48 in. inclusive. Western Continuous Ridge Ventilator For high volume, low velocity exhaust capitalizing on air movement generated by temperature difference plus induced draft, this ventilator provides a continu ous opening of any length desired in 17 throat sizes. The structure is storm and rain proof and is available with or with out adjustable dampers and screens. In herent characteristics qualify this venti lator for use in factories, foundries, mills and similar buildings. Forbes Syphonaire Westemaire Curb-mounted Fan A highly-engineered stationary type roof ventilator employing a circular wind band that prevents the entrance of out side air. High capacity, rain and storm proof, rugged construction, and low silhouette, obviating the need for guy wires. Wind tunnel tested by aeronauti cal laboratory. Sizes range from 6 in. to 48 in. inclusive. For low cost air movement under low static conditions, this unit is designed to meet practically every application in volving a roof-mounted exhaust fan* High speed, high velocity for industrial use or slow speed, quiet operation for commercial use. Available in 39 models. 8 in. to 48 in. Can be used in conjunction with any type gravity ventilator. SEE OUR COMPLETE CATALOG IN SWEET'S ARCHITECTURAL FILE AND ARCHITECTS AND ENGINEERS CATALOG FILE or write to above address tor additional catalog and list of Representatives. Forbes Econovent Gravity Western Airout, Gravity 1366 Booster Fan, Powered Air System Equipment Metai Sheets UNITED STATES STEEL AMERICAN STEEL & WIRE DIVISION. CLEVELAND COLUMBIA-GENEVA STEEL DIVISION. SAN FRANCISCO NATIONAL TUBE DIVISION. PITTSBURGH TENNESSEE COAL & IRON DIVISION. FAIRFIELD. ALA. UNITED STATES STEEL CORPORATION. PITTSBURGH UNITED STATES STEEL SUPPLY DIVISION. Warehouse Distributors. Coast-to-Coast UNITED STATES STEEL EXPORT COMPANY. NEW YORK U.S.S. GALVANIZED STEEL for high quality results and ease of fabrication U.S.S. Galvanized Steel Sheets are espe cially processed for the jobs they have to handle. They are uniform in flatness and surface. They can be bent, cut, stamped, rolled and formed--all with uunusal ease of handling. In the pro duction of U.S.S. Galvanized Steel Sheets careful attention is paid to the adherence of the zinc coating. This is done in order that forming operations may not fracture or flake the coating and thereby expose the base metal to atmospheric corrosion and rust. Because of all these outstanding quali ties, U.S.S. Galvanized Steel Sheets per mit true bends, tight joints and neat seams, even in forming difficult angles . ad shapes when working in close aDd confining, places. U.S.S. Galvanized Steel Sheets are produced in a wide variety of sizes and forms. Our engineers are specialists in their use and will gladly assist you in their application. Other U.S.S. Steels famous for superior service U-S.s. STAINLESS STEEL is ideal for in chemical plants, laboratories, and other places where highly corrosive at mospheres would spell early destruction lor less durable materials. Its high re sistance to corrosive attack, great strength, ease of cleaning and high re sistance to extremes of temperature are definite money-saving advantages. U.S.S. COPPER STEEL--coated or Uncated, insures increased resistance to corrosion, and increases life under all conditions of atmospheric exposure. U.S.S. GALVANIZED PAINTBOND STEEL--for ductwork requiring imme diate painting without preliminary treatment or weathering. Paint will not flake. Bonderized surface prevents dete riorating action between paint and gal vanized coating. A similar sheet, U.S.S. DULKOTE, is available in the South and the West. 1367 Air System Equipment aV^S^S. Grmer Air Control Products, Inc. Coopersville, Michigan . Air Conditioning Registers. Grilles. Ceiling Diffusers and Leigh Building Products. NO. 10 SERIES REGISTERS AND GRILLES. A truly high value line that gives you top performance and appear ance. No. 10 Series Registers provide adjustable, dual control of the air stream. These Registers are made for sidewall or baseboard installation. They are available in a wide variety of standard sizes. NO. 10 SERIES REGISTERS are equipped with the famous Push Button operator that opens or closes at a touch of the finger. Air flow valve may be locked to any up or down deflection. A complete line of matching Grilles are styled to go with the No. 10 Register. NO. 110 SERIES REGISTERS NO. 110 SERIES REGISTERS have ver tical adjustable fins--used where a horizontal control of the air stream is needed. Single-shutter type damper. Operator sets close to face yet holds damper in position. Adjusto-Stop per mits use of damper as a balancing damper. NO. 210 REGISTERS NO. 210 SERIES REGISTERS have ad justable horizontal fins . . . for use where a vertical control of the air stream is needed. A single-shutter damper is used to open or close the Register. Grilles are designed to match Registers. Like the No. 10 and No. 110 Series, they are available in sidewall or baseboard design. All of the above Registers and Grilles are painted in beautiful Beige prime coat. # Installation frames to fit these Regis ters are available in a complete range of sizes. No. 60, 61 and 62 Series return air in takes are built with the same type of adjustable fins. Write for New Air Control Catalog. 1368 Air Control Products, Inc. 5. D.--Type Ceiling Diffuser Flush-Type Ceiling Diffuser Air System Equipment Registers and Grilles Air Diffusera CEILING DIFFUSERS Diffusers are built with a series of Air Flow Rings that discharge the air in concentric jets, resulting in rapid dif fusion of incoming air into room air. The curved contour of the formed Air Flow Rings discharges the air slightly downward from the ceiling with a minimum of resistance. On cooling systems, it delivers the air at ceiling level, where the cool air can settle slowly down into the room without chilling drafts. FLUSH-TYPE for installations where diffuser must be installed flush with ceiling. Air is deflected outward with a small amount of downward deflection. SD-TYPEhasstepped-down ring construction. Provides approxi mately 30 per cent greater free area than Flush-Type, and delivers air in a more downward angle. Both types are made in 7 sizes--6 in. to 22 in., and finished in Beige prime coat. Installation Rings INSTALLATION RINGS provide an easier, more substantial installation of Ceiling Diffusers. Easily screwed or riveted to end of duct or screwed to blocking. Forms a solid base for fastening diffuser and holds the pipe in shape. Not used with dampers. In sizes to fit all Air Control Ceiling Dif fusers. NO. 30 FLOOR REGISTERS--UnitGrid-Construction. A strong, rugged, low-priced Register. Face is stamped from one piece of heavy-gauge metal. Dial operator easily opens or closes the valve with a touch of the foot. No. 31 Return Air Face has the same Unit-Grid Construction as No. 30 Registers. Double- Valve Damper DOUBLE-VALVE DAMPER gives exact control of the air volume plus even air distribution over diffuser face. Butter fly-type valves are chain operated. Extra bell on chaiD permits system to be balanced at face. For 6 in. to 16 in. Diffusers. Single-valve Dampers avail able for 18 in. and 22 in. Diffusers. NO. 40 FLOOR REGISTERS feature famous RigidrLock type construction. Each fret is locked to each crossing fret and to the margin. Dial-operator valves run the short way of the face. Medium mesh CAg") between frets. No. 41 Eloor Return Air Faces have same Rigid-Lock construction as No. 40 Registers. Write for New Air Control Catalog--Contains Complete Size and Price Lists 1369 Air Control Products, Inc. < - Air System Equipment * Air Diffusers NO. 180 BASEBOARD PERIMETER DIFFUSERS Air Control Products, Inc. Air System Equipment Air Diffusers NO. 42 PERIMETER FLOOR DIFFUSER Designed for baseboard perimeter instal lation as a single unit, or in multiples for a continuous baseboard along one or more walls. Manufactured of heavygage steel, precision formed for a true fit. Diffuser is superbly engineered-- gives even air distribution across the entire face without the use of turning vanes or other resistance-increasing devices. Available in standard 4-ft sections. Also 2-ft section for small bathrooms or kitchens . . . same design and style as 4-ft section. Diffusers are finished in Beige prime coat--can be used as is, or painted to match baseboard or room. NO. 183 SERIES DAMPERS--Separate Damper unit for No. 180 Series Dif fusers consists of damper> chain, chain lock and 2 bells. Damper is springloaded so that it always opens, cannot fall shut and cause system to overheat. Permits system to be balanced at face. Made ini 2 sizes--12 in. x 234 in. and 14 in. x 234 >n* NO. 185 CONNECTOR SET. For connecting two or more No. 180 Series Diffusers together in a continuous base board. Simple and easy to use. Consists of 2 pieces-r-assembles fronts and backs together in a matter of minutes. NO. 50 SERIES BASEBOARD REGIS TERS. A beautiful gravity-type Regis ter that blends with any room interior. Removable face makes streak-proof in stallation easy. Outer shell stamped from heavy-gage metal. No welds to break loose. Balanced damper holds damper in any position. NO. 80 SIDEWALL GRAVITY REGIS TERS. Styled to match baseboard register. Adaptable for sidewall instal lation above baseboard. .With damper- Write for New Air Control Catalog Complete Engineering Data 1370 No. 4! One-piece face has no corner seams to mar the beauty of its curved, flowing contours. Smoothly curved vanes and wafer-thin valves reduce resistance, increase free-area and provide more efficient air distribution. Picture win dows and outside walls are blanketed with a layer of warm air--prevents cold drafts from flowing into the room. Adjusto-Stop screw stops the valve at any desired opening, balances system at diffuser face--eliminates the need for additional duct dampers. Vanes can be NO. 265 PERIMETER BASEBOARD DIFFUSER for out-of-the-wall instal lation where duct does not or cannot enter the wall. Adjusto-Stop permits the system to be balanced at diffuser face. Horizontal fins can be adjusted to throw air stream at any angle in relation to wall. Matching No. 262 Baseboard Grilles have same construction, without damper. Both units available in Beige Prime coat or Metalescent finish, in a variety of sizes from 10 in. x 6 in. to 30'n. x 6 in. Cutaway of No. 42 set for any desired deflection without shearing off at ends. Outstanding for use with conventional heating systems, perimeter heating and small-pipe per imeter heating. Standard Oak and Metalescent finishes. OPENING SIZES--10 in. x 4 in., 12 in. x 4 in., 14 in. x 4 in. and 14 in. x 234 in. Latter size is 15 in- x 3% in. overall-- ideal for narrow, hard-to-fit spaces under kitchen cabinets, in sill of large picture window, under stair risers, etc. NO. 15 SIDEWALL PERIMETER DIFFUSER Scientifically engineered to give a draftless blanket of air over the outside wall from a sidewall location. One size--10 in. x 6 in.--ideal for small pipe system. Provides complete, rapid dif fusion of air.' Works well on con ventional duct and may be used with loop or radial slab installations. Top section is flared away from diffuser face--prevents air from scrubbing the wall. Vertical fins in lower section spread air over wide area--parallel to the floor. Widespread air pattern insures blanketing of rectangular wall area. Balancing is accomplished easily at the face. Flat-spring linkage holds valve rattle-free in any position. Sponge rubber gasket seals against wall. Beige prime coat or Metalescent finish. No. 285 Perimeter Baseboard Diffuser FOR hew air control catalog 1371 Air System Equipment # Register* r and Grilles Air Devices Inc. Air Diffusers Exhausters Air Filters Filter Holding Frames Industrial Furnaces . 185 Madison Ave. New York 16, N. Y. ScTTmCD_^R_0_0_U_CT_S__J S Agents in AH Principal Cities AGITAIR DIFFUSERS TypeRC AGITAIR square and rectangular air diffusers are available with removable core and three distinct types of mounting frames, attractive in appearance, and practical for all job conditions. The removable core is a tailor-made dif fuser with patented built-in diffusing vanes. The vanes and louvers are as sembled in a wide variety of patterns and sizes to suit conditions of each applica tion. Air is discharged in one-two-three or four directions with each side deliver ing a quantity of air proportional to the area being served. These AGITAIR Dif fusers perform efficiently, quietly, draftlessly, with rapid temperature equaliza tion. Sqvart or Rectangular in Shape STRIPLINE Diffusers incorporate patented built-in diffusing vanes whichproduce extremely high turbulence and/ aspiration. Rapid temperature equaliza tion is achieved with maximum allow able temperature differentials between' room and supply air. STRIPLINE in-v sures an unvaried distribution of noise less, draftless conditioned air over a predetermined area. Hot or cold spots are eliminated in the zone of occupancy. Available in two styles and supplied as a continuous decorative unit or in sec tions. Type CSF Circular AGITAIRS combine beautiful design with finest operating features to give rapid temperature equalization and draftless diffusion of air. Available in various sizes and three distinct types: CSF, A, CM. AGITAIR WIND-ACTUATED EXHAUSTERS New method of installing AGITAIR Type "RC" Air Diffusers saves time and labor costs. Only two steps are required to finish installation: 1) attach mounting frame to duct collar. 2) Insert diffuser core and lock in position. For installation in acoustical ceilings AGITAIR square and rectangular dif fusers are made in sizes to conform to standard tile dimensions. The AGITAIR Diffuser Data Book, avail able to architects and engineers, will help you design and install air distribution systems. Consult our engineers. Provide proper ventilation regardless of wind direction, and with positive elicu* nation of down-draft. Functions peak efficiency at average low wind ve locities. Will not restrict the flow of or gases when there is no movement or out-door air across the head. Air System Equipment mToSL The Auer Register Co. 6600 Clement Avenue, Cleveland 5, Ohio Manufacturers of Registers and Grilles for Gravity and Air Conditioning Systems; Metal Grilles for Radiator Enclosure, Ventilation, Concealment AIR CONDITIONING REGISTERS AND GRILLES Auer has a complete line for warm air or air conditioning, a wide choice of styles for every purpose. For gravity sys tems, the Heat-Rite is a quality model, adjustable for up-or-down flow. DuraBilt floor registers and intakes provide extra strength with interlocked cross-bar con struction. "Streamliner" registers and grilles for high velocity outlets are made in 8 styles, with single bank of adjustable bars, vertical or horizontal, also with double bank, front vertical and rear hori zontal (or the reverse), also all these types with the addition of multi-louvre valves. Auer Register Book showing en tire line sent on request. Auer perforated grilles are made in many designs and sizes, in steel (or stain less), aluminum, brass or bronze. Fin ished or plated as desired. Grille Catalog. "G" gives full scale details, tables of openings and free areas. Streamliner Register No. 1005V-HML. Streamliner No. 1205VH. Double deflec Adjustable bars, multi-louvre valve. tion grille, adjustable bars. Airo-Flex No. 4432 Register-- Multi- louvres adjustable up, straight or down. Grille bars adjustable for right or left now. Grille to match. Airo-Flex No. 7032 Register--Grille bars set to direct air downward at 22^ deg, but adjustable for other angles. Single louvre. Grille to match. Registers for Perimeter Heating available in floor and baseboard types. 6 A--Square Lattice Grille 1373 SiA--Skell Grille Air System Equipment Anemostat Corporation of America ANEMOSTAT10 East 39th Street Representatives in New York 16, N. Y. DRAFTLESS DIFFUSERS Principal Cities 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 siphoned into the device where it is thoroughly mixed with sup ply air. The 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 occu pancy zone within low acceptable veloc ity limits is established. Stagnant air pockets are also avoided. The 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. This effective aspiration distinguishes Ane mostat Air Diffusers from all other air outlets. SMALLER DUCTS Aspirati6n permits the use of greater temperature differentials and higher supply air velocities than customary, which results in savings in the initial cost of fans and ducts and in,the operat ing cost of the system. Duct layouts may be simplified because Anemostat Air Diffusers distribute air evenly in spite of unusual room plans, columns or other obstructions. THE COMPLETE LINE Anemostat Corporation of America has developed air distribution devices and related equipment for every purpose. Circular, semi-circular, square and straightline Anemostat Air Diffusers of various types and sizes for ceiling and wail distribution are available for com fort conditioning and industrial heat ing, ventilating and air conditioning in stallations. These are available for both conventional and high-pressure> high velocity systems. 1374 Anemostat Corporation of America QUALITY Anemostat Air Diffusers are scientifi cally designed according to modern fluid flow theory and manufactured according to modern production standards. ANEMOSTAT PATENTS The Anemostat Corporation of America holds over fifty patents covering the use and design of diffusers in the field of air distribution. The superior function ing of the Anemostat is protected by these patents which are the result of in ventive spirit, diligent research and constructive engineering. RESEARCH AND ENGINEERING Anemostat Corporation of America maintains a large, well equipped labo ratory manned by experienced scientific and technical personnel for testing pur poses and the development of new prod ucts. Engineers from all over the world have visited the Anemostat laboratory to witness demonstrations of Anemostat products and their applications to any conceivable problem pertaining to air diffusion. Anemostat has spent over a million dollars in research and engineer ing and will continue to make substan tial contributions to the progress of the science of air distribution. experience Oyer a million and a quarter Anemostat Air Diffusers are now doing an excellent job in thousands of comfort conditioning and industrial heating, ventilating and air conditioning installations. In addition to applications in commercial buildings, industrial plants, hotels, stores, hos pitals, theatres, restaurants and homes, Anemostat Air Diffusers are used in military and commercial aircraft, rail road cars, buses and ships. SPECIAL INSTRUMENTATION Anemostat engineers have developed various instruments for the accurate and convenient testing of the performAC air outlets. The Anemotherm nlF* a self-contained, compact, portable instrument, facilitates the balncing and checking of air distribution ystems by engineers and contractors. .ls now commercially available and is ing used with great success by engiers and contractors throughout the country. 1375 Air System Equipment Air System Equipment anToSL Barber-Golman Company Air Distribution Products Rockford, Illinois Complete Equipment for Air Distribution Requirements. Adjustable for Precise, On-the-job Versatility. UNI-FLO Square Ceiling Outlets match tiles, have air-pattern control; VENTURI- FIX) Ceiling Outlets are versatile and adjustable, have wide range; LINE-O-FLO Ceiling Outlets have distinctive linear arrangement. SUPPLY, RETURN, and EXHAUST GRILLES or REGISTERS UNI-FLO Supply Grilles have high efficiency, low noise level, rapid diffusion, and directional control. UNI-FLO Return Grilles have high-efficiency features. UNI-FLO Double Deflection Grilles are widely adjustable. , Only a few of many are shown. Opposed-blade Volume Control is efficient, uniform, non-directional. Vol-adjustor controls air flow to outlets. Airturns in square ducts provide eddyless change of direction^ -. HIGH VELOCITY AIR DISTRIBUTION Terminal Outlets. Double Duct Mixing Boxes. Air Valves for Pressure Reduction and Control at Branch Take-offs. Plus other High Velocity EquipmeD^ Required for Air Distribution. Air System Equipment G?mfra Charles Demuth & Sons, Inc. Mineola, N. Y, Demuth Draftless Air Distributors Designed and Patented by Demuth Supply & Return Type (S) Type (/) Illustration showing curved vane principle The DEMUTH DRAFTLESS AIR DIS TRIBUTOR 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 turbulent streams, mixing room air with conditioned air, thereby providing constant air motion, uniform tempera ture and draftless distribution through out 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. Lighting Fixtures as illustrated by Type SL are standard accessories and are available in Type S, Type F and Type I. For pendant or other special lighting ap plications,please consult your local rep resentative or write direct to the factory. Volume Controls can, upon request, be incorporated into the diffuser at the time of manufacture. This device is intricate indesign and simple to install--two very desirable features. It adjusts the vol ume of air supplied without decreasing the efficiency of the DISTRIBUTOR. . Registers Air System Equipment "d Grilles " Air Diffusers CONNOR ENGINEERING CORP. Danbury, Conn. o* draft Representatives in All Principal Cities adjustable air difiusers . Ia Canada: Douglas Engineering Co., Ltd., Montreal, P. Q. CONTROLLED AIR DIFFUSION Kno-Draft Adjustable Air Diffusers are designed to give accurate control of air distribution, plus installation and oper ation economies. With air direction and air volume adjustments on each diffuser, "custom-made" air patterns can be created which will insure draftless dif fusion and equalized temperatures for comfort conditioning or specific patterns for industrial processes. Type KDA for supply air. Type SRD for combination Installation, balancing and inspection ,, . . ., .. . supply and return atr. are fast because of features like the Type Aluimnum, sizes 4 to 36 in. Sies etoU in. supply neck HD quick-opening set-lock assembly, the neck dia. Capacities 60 to di,a- Capacities 60 to 1,600 cfm per unti, return neck self-contained inner unit and the sleeve- ISflOO cfm per unit. area 75% of supply. type damper. System design problems are eased because Kno-Draft Diffusers are adjustable after installation. The often difficult and hazardous job of figuring everything about the air movement in advance is eliminated. And the air pattern in an area can be changed with the seasons or when processes, people or partitions are relocated. Kno-Draft Diffusers are geometrically proportional, size for size, insuring like re sistance at like neck velocity for any size--a considerable advantage when selecting various size diffusers for a common system. Designed for high or low ceilings or attachments to exposed ducts, these diffusers will effectively distribute large volumes of air and pre-mix room and supply air. They permit the use of high duct velocities-- resulting in smaller ducts and lower costs. Duct designs are simplified. The simple, attractive design of the Kno- Draft Diffusers enables them to blend with either period or modern interiors. In their original aluminum, they create an interesting and unobtrusive decora tive accent. Painted to match the ceil- Diffuser and Cone separated Diffuser and Cone assembled they become self-effacing. Anti-Smudge Cone: Where exceptionally sooty or dusty air conditions^are expected or where rough-textured ceilings are employed, the use of this accessory cone is recommended. It furnishes the additional control needed to provide the precise air separation which inhibits smudging. .TO K11KAI Mm AS 8 SCI At Amww HOCMt. Kno-Draft Diffusers are covered by U3. Patents Nos. 8J365,867;8J69.118; 8^68^89 and others pending; Cana dian Patents Nos. 489^06; USjttS. Any angle of air discharge needed to suit ceiling heights and heating, ventilating or coding air patterns can be de tained by raising or loitering bottom Cone B. 1378 Connor Engineering Corp. Registers Air System Equipment and Grilles Air Diffusers TypeD Air Volume Control operates independently of the air directional adjustment. It varies only the quantity, not the characteristic of the air distribution. It consists of a cylindrical, sliding, sleeve-type damper connected by a specially designed spider Fig. J Self-Contained Inner Unit Fig. 8 Type HD Set-Lock Assembly to a centrally operated'screw. The shank of the screw extends through the lower cone of the diffuser and is concealed by a tamper-proof cap. With this damper on each unit, a series of diffusers can be quickly balanced. Kno-Draft Features Speed Installation The development of the self-contained, removable inner assembly alone (see Fig. 1) reduced installation time as much as 60 per cent. The addition of the Type HD setlock assembly (see Fig. 2) reduced the time for that part of the installation to a matter of minutes. No tools are required. The B cone or inner clement of the diffuser is secured to the combined suspension and adjustment screws by a springloaded catch Fig. 3 Now Standard i( 1 Fig. 4 Air Direction /Equipment _ Adjustment Fig. 5 Balancing Fig. 6 Air Volume Adjustment which is kept in compression by a slotted washer. The holes in B cone pass over the bolt heads. All that is necessary is to press up on B cone and insert or remove the slotted washers. (See Fig. 3.) Even where ceilings already exist, the outer cone is easily attached to a duct or collar. The air direction adjustment is also accomplished quickly. All that is needed is a screwdriver to adjust the suspension screws for any angle of air discharge from hori zontal to vertical. (See Fig. 4.) System balancing is fast and simple. The single annular air stream permits im mediate and accurate velometer reading. (See Fig. 5.) Desired air supply ratios may be rapidly obtained by adjusting the volume control dampers. A twist of the wrist regulates the volume instantly. (See Fig. 6.) Nation-wide Sales and Engineering Service Connor Engineering Corp. maintains a research laboratory with a staff of trained specialists and district represen tatives in leading cities. Their services arc at the disposal of consulting engineers, architects, air conditioning dealers and plant engineers. They can assist you in getting the best possible performance from your air conditioning system by creating custom-made air patterns which will thoroughly mix room and supply air, eliminate drafts and maintain uni form temperature throughout an area. . Free Handbook on Air Diffusion ^ contains the latest engineering data on air diffusion and is profusely illustrated w>th charts, photographs, sketches and dimension prints that simplify the selection, aPplication, location, assembly, erection, testing and adjusting of Kno-Draft AdjustaP*e Air Diffusers. It is designed to help you get top efficiency from an air con ditioning system by creating "custom-made" air distribution patterns. *or your FREE copy, please write Dept. Y-29. (See pages 1878 and 1873 for data on Dorex Air Recovery and Air Purification Equipment.) 1379 Air System Equipment SJSffi. Hart & Cooley Manufacturing Co., Holland, Mich. Air Conditioning Registers and Grilles--Warm Air Registers Damper Regulators--Furnace Regulators--Pulleys--Chain NO. 74 DESIGN--Economy Type Air NO. 76 DESIGN--For Shallow or HoriConditioning Register. Flexible-fin face zontal Ducts. An ideal air conditioning permits any up or down deflection of airflow. Positive, single-shutter valve with stop screw beneath valve handle for accurate volume control at the register face. Sponge rubber gasket prevents streaking. Finest quality con struction. Available as Sidewall and Baseboard Registers in sizes 8x4 through 14x8--Grilles 8x4 through 30x8. NO. 75 DESIGN--For Air Conditioning at Its Best. Flexible-fin face provides register for shallow or horizontal ducts which will not accommodate the turning blade valve of our No. 75 Design. Multi-shutter valve (depth lj| in. from wall) and flexible-fin face provide for all deflections desired. Any desired up or down deflection can be maintained with adjusting screw beneath valve handle. Sealed to prevent streaking. Sidewall and Baseboard type Registers, in sizes 6x4 through 30x8. NO. 88 DESIGN--Shallow Ducts, Large Installations. Similar to our No. 76 for any deflection of airflow sidewise. Turning-Blade Valve, an exclusive H&C feature, smoothly turns airflow up, straight or down with 30 per cent less resistance than other valves. Assures thorough distribution to all parts of room. Instantly adjustable. Sponge rubber gasket prevents streaking. Available as Sidewall and Baseboard Registers in sizes 6x4 through 14x8. Grilles 6x4 through 30x8. except that face bars are pivoted and adjustable in 2 in. sections (one moves all in section). A deluxe sidewall register and particularly advantageous for large installations. Largest size, 30x24, has only two valve handles. Removable handle available to avoid tampering. Sidewall Registers or Grilles 6x4 through 30x24. INSTALLATION FRAMES TO ACCOMMODATE ALL THE ABOVE ITEMS ARE AVAILABLE. No. 75 Design Turning Blade Valve CEILING DIFFUSER--Primarily designed for use with residential package heating, where its low resistance eliminates the necessity of changing the blower. Will also do an excellent job on any residential or small commercial heating or cooling in stallation. 5 popular sizes. Gasket prevents streaking. 1380 Hart & Cooley Manufacturing Co. NO. 401 DESIGN--For Perimeter Heat* ing. The No. 401 "Diffusaire" Sidewall Register, installed above the baseboard on outside w alls, provides an excellent means of blanketing cold wall and win dow areas with a curtain of warm air, thus counteracting downdrafts of cold air from these areas. With this register the air is dispersed in a full 180 deg spread upward in addition to permitting a portion of the airstream to De directed downward over the floor. An adjustable stop on the handle permits balancing the system at the register face. Avail able in sizes 10x6, 12x6, and 14x6. NO. 411 DESIGN--For Perimeter Heat ing. No. 411 "Diffusaire" Floor Regis ter is specifically designed for perimeter heating to counteract downdrafts from windows and cold walls. Opposed louver valve mechanism with set screw adjustment provides accurate volume control for easy balancing of the system. Design of diffuser blades permits even spread of air in fan shaped pattern with minimum amount of resistance. Avail able in sizes 2J in. x 14 in., 4x10, 4x12, 4x14, 6x10, 6x12, 6x14. NO. 130 DESIGN--For Gravity or Con version. This Baseboard Register has a removable face, flexible fins which may be easily adjusted to desired up ward or downward deflection of airflow, valve that holds securely under all conditions, and approximately SO per cent free area. It's tops for gravity installations and as a replacement regis ter where an existing gravity job is converted to forced air. Furnished in beautiful METALUSTRE finish in sizes 10x8 through 13x11. NO. 330--Sidewall Register. Compan ion piece to the No. 130 Baseboard Register. Furnished in sizes 10x8 and 12x8. Air System Equipment anfcdiies NO. 210 "NO-FLEX" Floor Register. Grid-type, very sturdy with heel-proof mesh in. x Iff in.). Free Area is over 75 per cent. All steel body with smoothly operating valve running the short dimension. Furnished in all standard finishes including Oak. Sizes: 4x6 through 30x30. NO. 265 RETURN AIR FACE- -Matches No. 210 Register. FOR COMPLETE DESCRIPTIONS AND ENGINEERING DATA OF THESE AND OTHER ITEMS WRITE FOR CATALOG. 1381 Air System Equipment g^*"5 Hendrick Manufacturing Company - 48 Dundaff 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 of a deflecting vane grille and an ornamental grille Now you can secure in a single installa tion all the advantagesof an adjustable vane grille--to direct air flow--and an left, up or down, or in a combination of both directions. For the imposed ornamental grille sec tion of the dual-unit Bulator, Hendrick offers a wide selection of attractive de signs, with the essential open area. Tested at Case Institute ornamental grille--to harmonize with the To determine the efficiency of the dual decorative scheme--by specifying the new unit, tests were made at the Case Insti dual-unit Hendrick BULATOR*. It is a tute of Technology, Cleveland, under the practicable combination that meets both direction of Professor G. L. Tuve, as a the engineer's specifications for air throw result of which, "it was found that at a and spread, and the decorative require given air volume, the presence or absence ments of the architect. of the `Mosaic' (design) grille made very In this dual-unit, the deflecting vanes little difference on either the air stream are not noticeable, although they are pattern or the throw." mounted just behind the ornamental A copy of the detailed report on these grille. The vanes are adjustable so that tests will be mailed on request. the air flow can be deflected to right or How to specify or order ' Hendrick Bulators liiliililliiliiliiliiliilii In specifying or requesting quotations on the Hendrick dual-unit Bulator, the fol liiliililinHiiliiliiliiliil lowing information is required: 1. The name or description of the de sired ornamental grille, as given w Photograph taken with deflecting vanes less than an inch behind grille, shows that vanes are not noticeable. the Hendrick Grilles catalog. 2. The metal, gauge and finish of the ornamental grille, that is required. 3. The dimensions of the air duct opening. 4. The type of deflection desired in the deflecting vane section; whether . right and left, up and down, or a combination of both. Vertical deflecting vanes, showing how the panes may be set to produce any desired air stream pattern. Beauty + Ventilator 1382 $ Hendrick Manufacturing Company Air System Equipment HENDRICK PERFORATED METAL GRILLES Hendrick decorative grilles are fur nished in over a hundred patterns, and in a wide variety of overall dimensions, bar sizes, and number and size of per forations. Many exclusive Hendrick designs, orig inally produced to meet an architect's specifications for some particular proj ect, are now available as standard numbers, and facilities for making spe cial designs to specifications make the Hendrick service even more complete. The wide range of patterns permits the choice of a grille that will harmonize with any style of architectural design or period construction. Arglin--63 per cent Open Area Grilles are fabricated in heavy-gauge 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 opera tion in their manufacture. Argive--60 per cent Open Area li^i! IOT \rn\ IMIIMHIJIS3! KS2! M liSSil li&Sil li&Sif li&Sf lifrSil li&fiil liStfit Ill'll La Crosse--66 per cent Open Area AIR CONDITIONING GRILLES AND REGISTERS Hendrick air conditioning grilles and registers for directed air flow are made in various meshes, the standard having % in. opening between face bars. All types are furnished with either horizontal or vertical directional bars. The standard mesh can either be fur nished with grille bars permanently set at the factory for straight or directional air flow, or furnished so that the grille bars may be individually adjusted on the job to direct air flow to any desired degree. M-No. t--67 per cent Open Area Front View RearVicw M-No. 9--$7 per cent Open Area 1383 < - Air System Equipment The Independent Register Co. Eetcabiabhrd 1898 3747 East 93rd Street, Cleveland 5, Ohio AIR CONDITIONING REGISTERS AND GRILLES No. 321A Grille with Deflecting Vanes--With vertical grille bars and horizontal de flecting vanes. The grille bars may be individually adjusted to direct air flows to right or left; and the vanes are made individually adjustable to deflect air flows up or down. No. 238 Wrought Steel--d-way adjust able direction of air flow. Flexible ver tical grille bars, multiple valves. No. 139 Wrought Steel--Flexible hori zontal grille bars, bendable for up, down or straight air flow. Single valves. Independent No-Vision Grilles--No. 1312 for Doors, Walls and Partitions The grille bars are "V" shaped; it is impossible to see through the grille from any viewpoint. No. 1312R--With overlapping rim H wide, on all four sides. No. 1312C--With grille core only, stalled with moulding. 1384 Air System Equipment At Diffusers Knowles Mushroom Ventilator Co. Established 1906 All Patents Protected Main Office and Factory Upper Montclair, New Jersey Thiyicfch NU-NOTCH Specifications Furnish and install where indicated on drawings or as hereinafter specified (5in.) (6in.) (7 in.) (8in.) (lOin.) (Dome Top) (Flat Top) Nu-Notch Cast Iron Mushroom Air Diffusers with recessed notches for the permanent adjustment of mushroom caps at any desired open ing, together with center locking screw feature. Provide under each Air Diffuser one No. 20 Galvanized Iron Sleeve to be set by the heating contractor in conjunction with the general contractor at the time the floor is laid. In concrete floors when sleeves are located on forms fill sleeves with sand before being grouted in, to prevent their distortion. For wood floors --attach the mushrooms to the floor by means of flat head screws. For concrete or similar type floors--by tightening 3 set screws in the collar. (In specifications indicate the desired size and style of top.) MODERN practice shows that 8 cu ft of fresh air per minute per person is ample to keep the air in an auditorium free of odors; and to maintain body heat and to balance the outdoor heat of a warm summer's day, about 20 cu ft per minute per person must be introduced. The accurate amount becomes an engi neering problem too extended for this outline. Of the 20 cu ft per minute per person introduced, 12 cu ft may be recirculated, economizing heat in winter and cooling jn summer. If too much air is recircujated, odors will result; and when Bmok- mg is to be allowed, much more new air must be introduced. KNOWLES NU-NOTCH MUSHROOM AIR DIFFUSER For Auditoriums Cast iron mushroom, successfully serving in over 5,000 buildings in U. S. and abroad. Provides correct draft-free distribution of air to each individual in any size auditorium, orchestra or bal cony. Close regulation of air--10 differ ent adjustments for all possible condi tions. Easily regulated by part turn of cap, and locked in position by tightening head screw with special key--new feature to prevent tampering. Supplied with dome or fiat tops, 5 diameter sizes. Easy, permanent anchorage to wood, concrete or monolithic floors. PROPER auditorium ventilation is now recognized to be a combination of temperature, air motion and distribu tion, humidity, dust, bacteria, odors, and carbon dioxide. Air motion and distribution is second only to tempera ture in importance. The Synthetic Air Chart adopted by the A.S.H.V.E. takes into account all of these factors and makes it possible to arrive at an average which will show the percentage of ven tilation obtained in any given installa tion. For nearly a half century KNOWLES has devoted itself to one specialized field --the manufacture of air diffusers for auditoriums. . Write for free Guide to Distribution of Air in Auditoriums. ^jJjPtability of the KNOWLES Mushroom Air Diffuser. In an auditorium seatmg 2000, requiring 40,000 cfm, it is desired to use 6 in. dia. NU-NOTCH Mushrooms ^Hh air velocity of 600 fpm. By referring to the table below, it will be seen that y in. mushroom will exhaust 120 cfm. Dividing 40,000 cfm by 120 indicates 333 units are required. mensions in Inches Net Area Wgt. Sq Cfm at Velocity of B C D E F Lbs. Ft 200 250 300 350 400 450 500 550 600 A IK 56 4 lit IK 1W 6 7 A 4K IK 2K IK 7 8M 6H IK 2 2 8 low 9 IK 3 m 10 11A 14K .1364 .1964 .2673 .3491 .6454 27.3 39.3 63.5 69.8 109.0 34.2 49.1 66.8 87.3 136.3 41.0 59.0 80.2 105.0 163.6 47.7 68.7 93.5 122.0 191.0 54.6 61.2 68.0 78.6 88.2 98.0 107.0 120.6 134.0 140.0 157.0 174.5 218.0 245.2 272.5 74.8 81.6 107.8 117.6 147.4 160.8 192.5 209.4 300.0 327.0 haucitV!! <Va* Nu-Notch is the most economically priced Mushroom to use also affording the greatest ex1 area and least duct connections. 1385 4 ;. 7:f! :!ii ! ' MULTI-VENT* LOW VELOCITY AIR DIFFUSION PANELS Multi-Vent installations are simple, quick to balance and easy to clean. They have been applied with remarkable results to almost every type of building, new or old, and are particularly well adapted to the lower ceilings and movable partitions in modern architecture.' 11 Outstanding Advantages 1. Radiant Panel Heating and Cooling Effect Adds to ths Comfort Factor-- The large areas of the ceiling which function as distribution plates for the Multi-Vent panels are heated or cooled to the temperature of the supply air. MULTI-VENT*--LOW VELOCITY DISTRIBUTION BY DISPLACEMENT Dm Vdsrily iooo fpm Wjintntt 300|_ J / Wb cm 1 / \1 / rTnTTTiTTFiXT V mil \ n" III! W-'fll I I I I I Xl t I I l I II I `S.`S' I I II I I I I I I iXl OA.MW,! | io-5onM_| |J III I I | I I l*?rJf> "" OTHER DIFFUSERS--DISTRIBUTION BY HIGH VELOCITY INJECTION 2. Complete Absence of Strong Air Streams or Blow Eliminates All Air Di rection Adjustments by Diffusing Vanes or Baffles: With Multi-Vent duct veloc ities are so radically reduced (within the diffuser itself). . . diffusion is so rapid, thorough and wide-spread . . . that no air movement in excess of ASHVE com fort zone requirements exists more than six inches away from the perforated distribution plate. 3. No Deflection Problems to Restrict Location or Capacity of Outlet Panel: With Multi-Vent the location and the capacity of the diffuser can be deter mined solely by load considerations as suring maximum effectiveness and effi ciency. The proximity of seating loca tions or the relative positions of parti tions and lighting fixtures--which must be a major consideration in locating high velocity diffusers to avoid drafts--need not be considered with Multi-Vent re gardless of ceiling heights. 4. Complete Freedom of Partition Move ment With No Panel Alteration or Ad justment Necessary: In resizing office or store space Multi-Vent panels can even l>e bisected by partitions with no possi bility of draft hazards or other unde sirable air diffusion problems. . Dm Vtbdty IOOO PPM Nadi Sit* SdrrttJ bf 300 CfH Oitte VekdlT 700*1500 fPM 5. No Change in Air Diffusion Patterns or Cold Drop When Desired Volume of Air Delivered is Varied: Multi-Vent's adjustable pressure displacement valve can be easily set for delivery of various amounts of air without disturbing the balance of the overall system. Neither single panel adjustments to suit occu pants special requirements nor substan tial reduction or increase of air capacity at source to meet seasonal demands will in any way affect the desired air flow pattern. 6. 40 Per Cent Higher DTD Will Meet Comfort Zone Requirements: Multi Vent will permit raising the usual 15 deg Diffusion Temperature Differential to as high as 25 deg (with an 8 ft ceiling for example). Thus 40 percent less air need be used to handle a given load making possible substantial economies in ducts, fans, filters. TAt* application ofIoid velocity, pressure displacement 7. No Protruding Outlets to Intel fere air diffusion is fully protected by patents. Only with with Style and Location of Lighting Multi-Vent can you enjoy its benefits. Multi-Vent is the registered trade mark of the Pyle-National Co., Chicago, air distribution systems and parts thereof. Fixtures or with Interior Ceiling Design --Multi-Vent panels are completely con A1386 cealed in metal acoustical ceilings. Installed flush in any other type ceiling, Multi-Vent is less conspicuous than diffusers of any other make. 8. Exceptional Uniformity and Control of Room Temperature: Multi-Vent can achieve a temperature differential of as little as 1 deg within the comfort zone in all seasons. This insures true air conditioning comfort and will meet the most exacting air conditioning require ments for scientific research and indus trial processing. 9. More Room Air Changes Per Horn With Less Air Motion: Multi-Vent is designed to handle the greatest amount of air in proportion to room size and therefore is particularly well suited to locations having high load or high ven tilating requirements. 10. Elimination of Dirt Impingement on Ceiling and Wall Surfaces Reduces Costly Redecorating--Dirt Particles are not driven into paint and plaster by horizontal high velocity primary air streams, but are deposited gently down ward on easy-to-clean furniture and floor surfaces. 11. Complete absence of the sound of rushing air. MVAR PANELS FOR MINERAL OR FIBRE ACOUSTICAL AND PLASTER CEILINGS 1. The Control Plate and Frame are in stalled in the bottom of the air supply duct of plenum or in a collar extending down through the ceiling. Control plate is mounted in frame on a piano hinge to permit cleaning and access to duct. Even with relatively inefficient air cleaning equipment, perforations will not clog. 2. The Pressure Displacement Air Valve is located in the center of the control plate. Its function is to control the volume of air admitted to the unit and to reduce both velocity and pressure of the incoming air. The valve is covered by a V-shaped primary diffuser, the de sign of which insures perfectly even dis tribution of primary air over the ceiling plate. Maximum air valve capacity 300 cfm. L The Perforated Plate spreads the de livery of the incoming air over a large area and further reduces the velocity to not more than 200 to 300 ft per minute. Because the perforations are small, the velocity of the air leaving the unit will be, in a typical installation, only 30 to ft per minute at 6 in. below the per forated plate. .The primary air in passing through the perforated plate and entering the conditioned space creates turbulence re sulting in considerable entrainment and such effective diffusion that temperature V?a^ons a^ anc* below breathing level ^ill not exceed 1 or 2 deg. Type MVAR Multi-Vent Panel for duct or plenum applications Panel Type MVAR-122-1 MVAR-123-2 MVAR-124-2 MVAR-125-3 MVAR-126-3 MVAR-244-1 M VAR-245-1 MVAR-246-1 MVAR-364-J MVAR-365-1 M VAR-365-2 M VAR-366-1 M VAR-366-2 Maximum Panel Frame No. of Air CFM Sizes--Inches Valves Capacity 12 X 24 12 X 36 12 X 48 1 75t 2 150f 2 I50f 12 X 60 12 X 72 24 X 48 24 X 60 24 X 72 36 T 48 36 X 60 36 X 60 36 X 72 36 X 7? 3 225f 3 225t 1 300f 1 300f 1 300t 1 300) 1 300t 2 600) 1 300) 2 600) t Valve capacity can be used only for straight venti lating and heating. Cfm limits on cooling are deter mined by DTD. Write for selection data. 1387 i Air System Equipment outlets and Graies THE PYLE-NATIONAL COMPANY Multi-Vent Division OUT-OF-SIGHT MODULAR PANELS FOR PERFORATED METAL PAN ACOUSTICAL CEILINGS Designed especially to minimize installation costs in both duct and plenum appli cations Air duct- 3-inch diameter opening cut during fabrication of duct in either bottom or- sides adjacent to panel location Tubing collar snaps into duct opening and seals with gasket Flexible and compressible Neoprene impregnated noncombustible fibreglass tubing permits wide tolerance in alignment . between duct opening and panel Bayonet-lock collar seals with gaske Adjustable orifice valve with wing nu Modular panel seats in ceiling pai Four swinging anchor clips, support panel on tee runners COMPLETE CONCEALMENT eliminates all interference with interior design and decorating detail. MATERIAL AND LABOR SAVING INSTALLATION FEATURES Duct work may be shop built and in stalled prior to and independent of ceil ing erection. No additional structural work, supports, cutting of ceiling pans, fitting, caulking or sealing ever required. Installation requires no tools or special skill. MODULAR PANEL is available with flexible tubing for duct applications; also without tubing but with perimeter gasket for plenum applications. ANY STANDARD PERFORATED 12 IN. x 24 IN. ACOUSTICAL METAL CEILING PAN (with acoustical pad removed) SUPPLIED BY CEILING CONTRACTOR--functions as distribu tion plate for Multi-Vent Panel. Pan encloses Multi-Vent panel and snaps into ceiling tee runner or radiant ceiling laterals in usual manner. Note! For information covering use of modular panels in acoustical block type ceilings write for special bulletin. DTD 15 20 25 PANEL COOLING ... CAPACITIES For All Ceiling Heights , CFM Limit Sensible Heat Absorbed BTU/HR _ 60 . 971____ 45 971 _____ 36 971_____ 1388 Air System Equipment Registers Grilles Register & Grille Mfg. Co. 70 Berry Street, Incorporated Brooklyn 11, N.Y. Sales Offices in principal cities in B. S. REGISTERS AND GRILLES HEATING VENTILATING AIR CONDITIONING SOLID BAR TYPE GRILLES AND REGISTERS Designed for the job where performance and quality are the first consideration. They are found in America's finest Schools, Hospitals and Public Buildings. Fixed or with Horizontal or Vertical Adjustment. TAMPERPROOF AND KICKPROOF. Built to withstand abuse. Easily adjustable with special tool pro vided. Interlocking Cross Bars for added strength. May be Chromium Plated for rest rooms and cafeterias. Predominant Vertical or Horizontal bars. Single and Double Deflection. Constructed of 14 gauge Steel Bars. 81 STYLES OF PERFORATED GRILLES Directrol--Quantrol--Aircon Shutter. Arrowtrol Shutter (for precise control) 13-W Frames--Arc Eng Complete Line of Registers and Grilles for HEATING--VENTILATING--AIR CONDITIONING Catalog on Request 1389 Air System Equipment gIS Standard Stamping & Perforating Co. 3111 W. 49th Place, Chicago 32, Illinois Air Conditioning Registers and Grilles--Cold Air Faces Perforated Metals for all Purposes . No. 551 Perimeter Wail Register Gives four way air diffusion. Equipped with Fractionator Volume Control and Damper Tension Screws. Also available with a base extension as Model No. 451 perimeter base board register. No. 331 Sidewall Register Horizontal multiple valve louvres at tached to vertical "bend-ezy" faces, adjustable for four way deflectiou. C-F5 Perimeter Baseboard Register Made in 4 ft sections, each section with individual sliding damper that allows al most perfect air control and balancing at outlet. Sections can be joined for con tinuous installations. End caps avail able along with Butt Straps, Lugs for attaching, backs, and set screw locking feature as accessories. No. 100-LO Multiple Louvre, Lever operated register. Also available as: 100-KL, a Key Oper ated register: 100-RK, a register with a Removable Key; 100-PO, a Pulley Oper ated register (especially suited for inac cessible installations). Register faces are attached to louvre boxes with screws so that the boxes are detachable. ******************** ******** *8 ** *>3 ** ***i? ****** ** I** * * *'* * * I** iS1^ *******I* *IS *S * I* ** *I* *fi* ****** (9* * *I** * ** ** * * ******** * * * * SJ * IS * I* * ^ Union Jack Design All Standforated Grilles and ornamental designs are available in steel from 16 gag6 to I in thicknesses. They can also be furnished in non-ferrous metals, such as aiu minum, brass, bronze and stainless steel, and in varying thicknesses according w the physical properties of each metal. Complete specifications will be furnished upon request 1390 Air System Equipment g^SST* Stewart Manufacturing Co., Inc. Cedar Grove, Essex County, New Jersey IN CANADA: Air-Care, Ltd., 2125 Marcil Aye., Montreal 28, Quebec Technical and price information available through representatives in all principal cities, or at factory headquarters. A complete line of Registers, Grilles and Scoops for all types of Industrial and Resi dential air conditioning applications. The STEWART line includes more than 50 styles in 2100 sizes, for a wide range of special as well as standard requirements, to meet every engineer and contractor need. Engineering data available per mit easy selection for large or small in stallations. Stainless steel, aluminum and brass are available in all products as well as the standard cold rolled steel. Patent Applied For SCOOPMASTER--designed to eliminate the sheet metal collar on exposed duct work, to speed up the difficult task of balancing the system and to obtain direc tional control of the air. Consists of a combination of the Scooptrol and DH outlet. By means of the screw type mechanism the scoop portion of the Scoopmaster is extended back into the duct, or brought closer to face of the outlet. Variations available to meet un usual job applications. DEFLECTAIRE--Style DDH, ALL-WAY SELECTIVE AIRTHROW--Has two banks f individually adjustable fins--front bank horizontal, rear bank vertical. Fins are streamlined. Bank of opposed action valves can be furnished as addition or sub stitution. Overall size of face 2 in. larger than duct opening. PLASTER FRAME permits removal of grille when desired without damage to surrounding painted areas. . Send for new illustrated Catalog No. 54 1391 Air System Equipment J AIR CONDITIONING OUTLETS KS Titus Mfg. Corn, WATERLOO, IOWA Titus Mfg. Corp. are designers and man ufacturers of Airfoil Grilles featuring the Airfoil Louver--patterned after the airfoil section of an airplane. The follow ing distinctive features identify Titus Airfoil Louvers. (1) Smooth as glass streamlined surface (2) Solid construc tion (3) Noiseless performance (4) Mini mum turbulence. 276 4-Way Multi-Shutter Register Con sists of the #270 4-way directional grille combined with a multi-shutter damper. Damper blades inter-locked when closed to provide complete shutoff. 270 Airfoil Grille Gives 4-way directional control. Lowers set on % in. centers. In dividually adjustable to create any air pattern desired. 277 4-Way Registers with opposed blade dampers. Two front, sets Airfoil louvers individually adjustable, I in. spacing. Opposed blade damper key operated in rear. * 274 Multi-Shutter Register Airfoil Lou vers are featured in front. Individually adjustable. Rear multi-shutter damper blades. 230 Return Air Grille--blades on i in. centers. Parallel to long dimension. Deep fins. Standard 1 i in. beveled border. Any size grille can be furnished. R-240 combines #2.30 return air griljn 275--Double deflection register with op posed blade damper, key operated. with multishutter damper blades. R--"1 combines #230 with opposed blade damper. 1392 Titus Mfg. Corp. Air System Equipment Registers Grilles AG-25 Volume Controllers provide posi tive control of air volume. Blades indi vidually adjustable. Sponge rubber gasket holds unit firmly in duct. T-700-B--No Vision door and partition grilles. Made with flange frame or chan nel type frame. All steel--V-shaped louvers on in. centers. Widely used for exhaust and return air grilles. AG-35--Superior opposed acting volume controller. Provides complete control of air volume to the outlet with minimum disturbances of air pattern. Louvers move simultaneously in opposite direc tions and can be set at any degree from full open to full closed. AG-45--Air volume extractor and con troller. Will control air volume and also produce balanced air distribution. Re places extra volume controller. Fifty percent savings on cost and installation. CONVECTOR GRILLES--Louvers closely spaced. Heavy-duty support bars on 6 in. centers. Over 70 per cent free area. Can be installed in any spe cial surface, such as marble or tile. Ex tra wide blades. Each "hemmed" for extra strength and safety. Available with damper and knob control. FRAME 115 FOR ALL AIRFOIL GRILLES AND REGISTERS Allows quick easy removal for cleaning or ad justing. Can be installed either before or after plastering has been completed. Frame may be embedded in plaster. Each frame has sponge rubber gasket to prevent air leakage. Edge acts as plaster lock. Designed for use with Titus Airfoil registers and grilles only. WRITE FOR NEW ILLUSTRATED CATALOG. FACTS, CONSTRUCTION, PERFORMANCE, SELECTION, SPECIFICATION. 1393  \; ; ; ; ;' . J: .. l { . !j 1 !. u :I Designed for installation in ducts be hind grilles, the VC-7 provides uniform distribution over face of the grille and permits positive damper setting in any position. Regulated by means of a screwdriver. Stocked in same 26 stand ard sizes as the TRI-FLEX line. 26 STANDARD SIZES 8x 4 10 x 4 10 x 6 12 x 4 12 x 5 . 12 x 6 14 x 4 14 x 5 14 x 6 16 x 5 16 x 6 20 x 5 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 30x10 30 x 12 36 x 8 36 x 10 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 Tri-Flex registers. Stocked in 20 standard sizes. 1394 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 30 x 12 30 x 18 30x24 36 x 18 36x24 36x30 48 x 24 48x30 48x36 Tuttle & Bailey Air System Equipment G?n&ere Type PA Type PS Aerofuse CEILING DIFFUSERS STYLE SIZES DESCRIPTION 6' 16' 8' 18' MT 20* 12* 24' 14' 30* 36' Adjustable diffuser designed so that air distribution pattern may be varied from horizontal to vertical. For installation on ceiling or exposed duct. 6' 16' 8' 18' icr 2C' 12' 24' 14' 30* 36* Fixed pattern diffuser with rings stepped down for added capacity. For installa tion on ceiling or exposed duct. 6' 16* S' 18* 10* 20' 12' 24' 14' . 30* 36' Flush type, fixed pattern diffuser which delivers supply air in a horizontal pat tern. For installation on ceiling. 8' 18' 10* 20* 12* 24' 14' 30* 16' 36' Flush type, fixed pattern supply and re turn (or exhaust) diffuser. For installa tion on ceiling. 8' 14' 10* 16' 12' 18* 20 Flush type, fixed pattern diffuser com bined with light fixture. For installation on ceiling. Type P1I Type D 14' Flush type, fixed pattern half-round dif 16' fuser. For installation on ceiling adja 18* 20* cent to side wall. W'xM' 16' x 16' 20* x 20* 24' x 24' 30' x 30* Square, fixed pattern diffuser that de livers air in 360 pattern. Type DF de signed for flush mounting in acoustical tile ceiling . . . Type DE, for installa tion on plaster ceiling. Other Aerofuse Diffuser types and accessories are available. 1395 Air System Equipment g^"* United States Register Company General Offices: Battle Creek, Mich., U.S.A. Branches: Minneapolis, Minn., Kansas City, Mo., Albany, N. Y. Air Conditioning Registers, Vents and Grilles No. 153--Single-Valve Air Conditioning Register-Bars % in. deep--Spaced 4 openings to the inch affords Non-Vision. Can be supplied in Directional Flow in either Horizontal or Vertical Bar Styles. Can be furnished with all styles of Setting Frames. No. 249--Multiple-Valve Air Condition ing Register. Gives complete Air Con trol. Vertical Front Bars--Key-pin ad justed to provide 45 deg Right and Left or Two-way Side Flow. Lever operated Horizontal Backvalves give from Full Closed to any degree of Upflow and to 45 deg Downflow. FULL FACE COV ERAGE. Can be supplied with any style of Setting Frame. Fits all Stack Heads of Standard Size Dimensions. No. 256--Multiple-Val ve Flex-bar-Air Conditioning Register. Vertical Front Bars set 22 deg Right and Left. Side Flow Deflection attained by setting of Grille Bars with bending wrench to accommodate room condition. Backvalves give same Up and Down control of air flow as No. 249 above. FULL FACE COVERAGE. Can he supplied with any style of Setting Frame. Fits all Stack Heads of Standard Size Dimen sions. All of above Styles can be supplied with either Lever or Individually adjusted Multiple Valves or Louvers, i. e. 177VVI--Vertical Valves Individually adjusted. 145VVL--Lever operated Vertical Valves. Grilles and Vents in Matching designs are available. For Complete Information Write for Catalog No. 53. No. 153-VVL Horizontal Bar Non-Vision Design-Vertical lever operated rear valves. Multiple Valve A. L. Registers available with Key Operation: Complete Gravity and Air Conditioning Register, as well as Fitting Catalogs furnished on request. 1396 United States Register Co. Air System Equipment g^"s No. 500 U.S. Ceiling Outlet No. 500 U. S. Round Ceiling Outlet. Made in 6 in., 8 in., 10 in., 12 in. and 14 in. sizes. Furnished with or without No. 900 frames. However, frames arc rec ommended. No. 500 outlets will be furnished with Dampers when required. No. 410 U. S. Perimeter Floor Register. No. 163% U. S. (Out-of-Wall) Air Conditioning Register is made in 10 x 6, 12 x 6, 14 x 6 in. sizes--with heads (No. 163%)--without heads (0163%). Intakes to match No. 173%, made in 5 sizes 10-12-14-24 & 30 x 6 in. "Dodge" old house troubles. Avoids cutting sills, joists, walls, carpets, rugs and floor. No. 163% U. S. Out-of-Wall Air Conditioning Register Valves of No. 410 run the long way to give "Away-from-the-Wall" deflection. No. 191 U. S. Multi-Flex Register Streamlined Double-Edged Grille bars. Front bank of bars--Horizontal Adjust able. Second bank of bars--Vertical Adjustable. Rear Valves--Horizontal Lever operated. May be furnished Key operated, or with Removable Lever. No. 191 U. S. Multi-Flex Register No. 190 U. S. Multi-Flex Register Stream lined, Double-edged Grille bars. Front Lank of bars--Vertical, Adjustable. Second bank of bars--Horizontal, Adjustable. Rear Valves, Horizontal Lever operated. May be furnished key operated, or with Removable Lever. No. 192 U. S. Multi-Flex Register--same as No. 190--but with Vertical Front Bars. No. 193 U. S.Multi Flex Grille--same as No. 190--but less Rear Valves. No. 194 U. S.Multi-Flex Grille--same as No. 191--but less Rear Valves. No. 195 U. S. Multi-Flex Grille--same as No.193--but Vertical Bars only. No. 196 U. S. Multi-Flex Grille--same as No.194--but Horizontal Bars only. See our Catalog No. 53 for the additional Non-Flex Register and Grille Line. 1397 Air System Equipment Air siansen Universal Diffuser Corp. 1360 Garrison Ave., New York 59, N. Y. ' Manufacturers of FLEXIFLO Adjustable Diffusers FUxiflo-Type R Flexifio-Tppe C VARIABLE EFFECTIVE AREA The FLEXIFLO diffuser is unique in that it has an infinitely variable effective area. All blades move simultaneously when the control knob is moved up or down. This provides a simple, effective means of controlling the volume of air. The pattern of diffusion for cooling purposes remains constant on the Type "R" FLEXIFLO. For cooling and heat ing purposes the Type "V" FLEXIFLO provides a variable pattern of diffusion from horizontal to downflow. Type R--For Cooling Provides a diffusion pattern and radius of diffusion that are not altered by change in air volume. Air leaving the Type R diffuser always travels parallel to the ceiling, assuring satisfactory per formance under all operating conditions. Type V--For Cooling, Ventilating and Heating Has a special blade configuration that gives a variable air distribution cone from horizontal to downward flow. Air can be delivered at practically any angle. Type CH--For Keating, Ventilating and Cooling Has concentric supply and return out lets with outer and inner portions con nected by sliding collars, the lower one fastened to the blades and the upper to the cross bar. The lower collar has a flared edge like the blades so that the delivery of air is shunted outward and peripherally, preventing short-circuiting of the room air. Type S--For Side Wall or Ceiling Instal lations Model SC is for ceiling installations in cooling work. Model SW is for wall installations. Evep' Type S diffuser has one set of equalizing deflectors. Type C TYPE "C" ADJUSTABLE SQUARE DIFFUSER. All blades move simul taneously when control knob is pushed up or down. Made for acoustical tile and plaster ceilings. 1398 Air System Equipment controis DaS^rs FG-75 COMMERCIAL TYPE GRILLE for Long and Short Throw. Each blade is individually adjustable to provide four wav deflection at degree desired. MULTI-SHUTTER or OP POSED BLADE dampers can be in corporated. Fins can be spaced on either in. or in. centers for fixed directional supply or return. MULTI-SHUTTER or OP POSED BLADE dampers can be in corporated . ADJUSTABLE STREAMLINED BLADES The EXCLUSIVE DESIGN provides unobtrusive diffusion. * SUFFICIENT SURFACE is provided to turn high velocity air without turbulence. MULTI-SHUTTER or OPPOSED BLADE DAMPERS Either type available with all Waterloo supply and return grilles. MULTI SHUTTER provides easy and accurate control of air volume for frequent one way adjustments. OPPOSED BLADE action allows uniform distribution of air over entire grille face. TECHNI-LOUVRE VOLUME Q . CONTROL suitable for installation either in the duct or junction of the duct and a branch take-off. Either half of each blade is adjustable independent of the DOOR VENTILATOR V-shape fins are spot-welded perma nently into frame at an angle which makes it impossible to see through. More than 57 per cent free area is ob tained. 1399 Air System Equipment. Duro-Dyne Corporation 38 South Franklin Street, Hempstead, L. I., N. Y. "DURO-BLADE-KIT" Damper Hardware for Multi-blade Dampers and Fire Dampers. ^URO-VANE-RAIL5 5 for making Air Turning Vanes Representatives in all Principal Cities "DURO-BLADE-KIT" PRECISION-ENGINEERED DAMPER HARDWARE Model shows how either parallel or opposed blade action is accomplished Multi-blade Dampers and Fire Dampers, when' constructed with "Duro-Blade-Kit" Precision-Engineered Damper Hard ware, assures you of these advantages: Produces commercial Damper of high quality. Smooth, non-binding Damper operation. Precision Engineering guarantees precise uniformity of all parts. Dampers completely adjustable after being installed. For construction of Parallel or Opposed-action blades. Fits all blades 3-in. or wider. Corrosion-resistant materials used throughout. Sturdy construction permits use on heaviest Dampers. No waiting for Dampers to be delivered. (Any good shop can produce high quality Dampers at appreciable cost saving with the "Duro-Blade- Kit"). Free Samples and Manual on Damper construction on request. "DURO-VANE-RAIL" For making accurate, inexpensive Air Turning Vanes "Duro-Vane-Rail" is Engineered so that any sheet metal shop can quickly and easily produce highly accurate and efficient Air Turning Vanes for Square or "Change of Size" Elbows. Rigid lock eliminates rattles. % Completed Air Turning Vanes con Vanes are set in "slots" in DuroVane-Rail. One blow on chisel cuts and bends protruding part of Vane in "slot" to form rigid, permanent lock. A chisel enclosed with each bundle of rails. Cutaway shows completed Vane Assembly tn Square Elbow. form to engineering specifications. Maximum free area because of stream lined fastening points. "Duro-Vane-Rair* lies flat in the duct and Vanes are rigidly locked. Eliminates rattles, whistles and Vane noises. ' Vanes can be either Single or Hollow. Free Sample and Manual on request 1400 Air System Equipment * ait fiow Regulators Young Regulator Company 5209 Euclid Avenue, Cleveland 3, Ohio DAMPER REGULATORS; REMOTE CONTROLS SYSTEMS Sales Representatives in Principal Cities No. Si5 No. 401 YOUNG DAMPER REGULATOR Meet practically every condition where control of air volume is required. No. 1--For installation on finished wall. May be locked in any position. No. 700CP--For remote control of one or more dampers at distances to 250 ft. Plate and knob chrome plated. No. 315--Concealed with adjustable cover for various thicknesses of acoustical ceilings. No. 401--Valcalox regulator for mount ing on duct. May be locked in any position. No. 403--Valcalox for mounting on duct, lever adjustment. May be locked in any position. No. 910--Convector regulator for op erating damper hinged on back of an enclosure. No. 900--Air split regulator for operat ing a splitter damper. No. 914--Concealed air split regulator with mitre gears used when the regulator is operated from a sus pended ceiling. No. 912--Concealed Air Split Regulator same as No. 914 for horizontal ACCESSORIES for YOUNG REGULATORS No. 9U No. 65$ No. 605 and No. 602--Bearing Sets. No. 4 and No. 5--Adapter for connecting rods of different sizes. No. 704--Corner Pulley eliminates fric tion where there are many turns. No. 656--End Bearing. YOUNG REGISTERS and DAMPERS No. 807--Register with damper for operation by remote control No. 700. No. 805--Damper only for operation by No. 1015--Volume control register gives equal distribution of air over entire grille and directional flow, remote control No. 700. __ _____ _ ___ . No SOS No. 807 No. 1015 for complete details see our Catalog in Sweet's File Architectural or Write for a copy. 1401 Bends, Coils, Fittings American District Steam Company, Inc. North Tonawanda. New.York SINCE 1877 EXPANSION JOINTS--HEAT EXCHANGERS STEAM TRAPS--STRAINERS--METERS SEPARATORS Bends, Coils, Fittings tgiS&SSta American District Steam Company. Inc. North Tonawanda. New York SINCE 1877 EXPANSION JOINTS--HEAT EXCHANGERS STEAM TRAPS--STRAINERS--METERS SEPARATORS PACKLESS EXPANSION JOINTS SLIP-TYPE JOINTS Adsco's Corruflex packless expansion Slip-type expansion joints, designed joints absorb pipe expansion and are for axial motion, offer long traverse, low adaptable to any piping condition. They are made in two basic types. The self-equalizing joint is used for various types of motion and is suitable for pres sures to 300 psi and higher. The non equalizing type is generally used to ab sorb vibration and a small amount of ex pansion under vacuum or pressures to 30 psi. Depending on the type of metal used in the expansion element, these joints are suitable for temperatures from sub zero to 1600 F. With variations in de sign, these joints will absorb axial, lateral, or angular motion, or any combinations of these motions. Some types handling these conditions are the universal, hinge, swing, gimbal, tie-rod, balanced, and anti-compression joints. initial cost, and produce minimum stresses and strains on pipe anchors. With proper maintenance, they will last as long as the pipeline. The piston-ring joint, illustrated above, with internal-external guiding, can be unpacked and repacked under full line pressure because of its piston ring feature. The polished, chromeplated slip is in contact with packing only. Hence, it cannot be scored by metal-to-metal contact. Packing can be quickly lubricated to prolong its life. The slip in the internally-externally guided joint is fully supported at both ends throughout its entire length of travel. The gland is not used as a guiding feature. They are made in nominal pipe sizes ranging from 3 in. to 54 in., with single or multiple corrugations. Most types can be supplied with covers to permit The internally-guided joint (not illus trated), being more compact, is espe cially recommended for use where space is limited. joints to be fully insulated and to pre Adsco slip joints are furnished in both vent foreign matter from being lodged single and double units, with flanged between the corrugations. When used ends or welding ends. Sizes range from for axial movement, joints can be 1)4 in. to 48 in. and traverse per slip is equipped with internal guide sleeves to 4 in., 8 in., and 12 in. Semi-steel joints provide a guiding feature and rigidity. can be used for working pressures to For other purposes they can be equipped 250 lbs and temperatures to 450 F. Steel with telescoping inner sleeves to reduce joints can be used for working pressures turbulence in the fluid being handled. to 400 lbs and temperatures to 800 F- 1402 INSTANTANEOUS HEATERS Adsco instantaneous heaters are made in a large variety of types, including the simple U-bend instantaneous heater, shown above, which is used to heat water for showers, dishwashers, laun dries, and other purposes. Many straight-tube, float-head units are used as closed feed-water heaters, boiler blow-down heaters, and for various uses in the process industries. The more simple designs heat water for .general service, for space heating, for cooling, etc. Other designs are used as suction oil heaters and oil preheaters; still other designs are used in high-temperature, high-pressure hot water installations for generating steam or heating water for space-heating systems. STORAGE HEATERS Adsco storage heaters are built in accordance with the ASME 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 non-corrosive metal, so that service water does not come in con tact with any ferrous parts. Steel tanks can be lined with Adsco Phenolic 6-2 or Adscote bitumastic to prevent corrosion. All units are equipped with cold-water spreaders. Manholes are heavily rein forced. Copper Unbend heating element is easily removed for cleaning. STRAINERS DUAL steam traps . No breaking of pipe connections to Protect regulators, pumps, valves, or traps with Adsco strainers. They re inspect and service Adsco Dual Steam move foreign matter from lines before it raps. All working parts are mounted on reaches expensive equipment. Screen is riiSX?r* Reversible valve and seat held securely by gasketed cap and special ouble life of trap. Dual inlet and outlet tapered fit. Furnished in semi-steel, 99nc.^bs. Automatic air bypass pro- bronze, or cast steel body, with perfor viaed in type T, shown above, by in- ated sheet or wire mesh screens of metal ernal thermostatic element. Extremely suitable for service. All sizes through ompact with large capacity. 14 in. and pressures to 600 psi. 1403 Bends, Coils, Fittings "5T Badger Manufacturing Company 230 Bent St., Cambridge 41, Mass. 60 East 42nd St., New York Representatives in principal cities Badger "PACKLESS" Corrugated Expansion Joint Badger "PACKLESS" Corrugated Expansion Joints For pipe lines--to compensate for expan- sion and contraction due to temperature changes, and.to relieve stresses and absorb vibrations. Bends, Coils, Fittings Expansion joints Flexonics Corporation EXPANSION JOINT DIVISION (Formerly Chicago Metal Hose Corp.) Maywood, Illinois District Offices ' Atlanta Boston Cincinnati Cleveland Detroit Ft. Worth Houston Los Angeles New Yore Philadelphia St. Louis San Francisco In Canada: Flexonics Corporation of Canada, Ltd., Brampton, Ontario FLEXON CONTROLLED-FLEXING EXPANSION JOINTS For pressures up to 300 psi--temperatures to 800 F Thecontrol ringsofFLEXON ControlledFlexing Expansion Joints provide guided flexing of the joint and prevent any permanent deformation of corrugations. Control rings are firmly anchored into corrugations to close working dimension tolerances. Expansion travel up to 7J in. may be secured with a single FLEXON Expansion Joint. Standard sizes from 3 in. to 48 in. N.P.S. in either stainless steel or copper. Available with or without stainless steel internal sleeves. (Left) Badger Non-Equalising "Packle&s" Corrugated Expansion Joint, Sot low pressure service and to ab sorb vibration. Single Corrugation. {Bight) Standard Flanged-End Badger Directed Flexing Self-Equalising "Packless" Corrugated Expansion Joint. . INSTALLATION, OPERATING, MAINTENANCE ECONOMIES Flexible--Reduces to a minimum the Directed flexing, all-curve corrugations thrust on adjacent equipment. plus all-curve self-equalizing ripgs-- "Packless"--Made from a single tube. .. no packing ... no servicing ... no man holes or tunnels are required. Wide range of traverses--By varying the number of corrugations, traverses from a fraction of an inch up to any practical limit are possible. Exclusive features on Badger Joints pre vent stresses from localizing--assure long life, greater dependability. Rings limit and progressively control flexing movement. Flanged and Welding Ends available as Engineered Relationship between Diam eter of Joint, Depth of Corrugation and Traverse to be Handled. Wide range of pressures--Standard joints for normal pressures . . . special joints for higher pressures. standard equipment. Heat treatment--Scientific heat-treat ment during manufacture removes form ing stresses. . . lengthens life of the joint. Compact, easy to install--Outside diam eter is about the same as regular pipe flange--nothing clumsy or hard to in Available in copper, stainless steel and other metals--To meet temperature, stall. pressure and corrosion conditions. 1404 FLEXON Controlled-Flexing Expansion Joint with flanged ends. FLEXON Controlled-Flexing Expansion Joint with Welding Ends. FLEXON FREE-FLEXING EXPANSION JOINTS For pressures up to 30 psi . . . temperatures to 850 F FLEXON Free-Flexing Expansion Joints are made with single or multiple cor rugations. Designed for expansion travel up to 3f in. per unit. Used in low to mod erate pressure systems to compensate for expansion and for correcting piping misalignment. Standard sizes from 3 in. to 48 in. I.D. in either stainless steel or copper. Avail able with or without stainless steel inter nal sleeves. Single Corrugation FLEXON Free-Flexing Expansion Joint wiii flanged Ends. FLBXON Free-FlexingExpan sion. Joint with multiple cor rugations and flanged ends. FLEXON Free-Flexing Expan sion Joint with welding ends. FLEXONIFLEX EXPANSION JOINTS For pressures to 5500 psi . . . temperatures to 1600F FLEXONIFLEX units make it possible to utilize the expansion joint's advantages of compactness and simplicity of installa tion at pressures far beyond those which had previously been considered safe. Dependent upon size and temperature these units will handle pressures up to 5500 psi. Standard FLEXONIFLEX units have stainless steel pressure carriers of the bellows type formed within integral control rings and end sections. They are available in single or multiple ply, lined or unlined. Sizes range from i in. pipe through 6 in. pipe. 1405 Bends, Coils, Floats Arthur Harris & Co. 210-218 N. Aberdeen Street . __ Engineers--Metal Float Manufacturers . Chicago 7, 111. Floats Fabricated of Aluminum, Brass, Copper, Admiralty, Everdur, Monel, Nickel, Inconel, Stainless Steel, Type 304, Type 316, etc., Steel and other Workable Metals Floats can be plated with copper, nickel, chrome, zinc, tinned, or lead coated. Special connections can be furnished where required, but standard B-262 ball floats are provided with standard female pipe spuds---unless special connections are or dered. Stainless steel, steel, nickel and monel floats, are suitable for high pressure and high temperature. Where corrosion is a factor, our catalog should be consulted so that floats of suitable material can be furnished. Open tank floats can be loaded with sand, lead or steel to bring them to a desired weight. Aluminum floats are vulnerable to corrosion by many solutions, but also give satisfactory results when properly used. Metal Floats Column Ball Flat Cylindrical Cylindrical Cylindrical Seamless copper ball floats carried in stock in diameters of 3 in., 4 in., 5 in., 6 in: 7 in., 8 in., 10 in., and 12 in. for open tank. . . . 25 lb, 50 lb, 100 lb, and 150 lb working pressure. Copper floats of special sizes and for special pressures made to order. Stainless steel ball floats in. to 12 in. diameter for high pressure and corrosion carried in stock. Special stainless steel floats made to order.--Copper Ball floats of 12 in. and to 18 in. diameter, and stainless steel floats over 12 in. to 14 in. diartieter made to order. Consult our Engineering Department when you have float problems. Catalog on request. Copper plated--brazed joint--steel ball and special floats for high and low pressure. Ask for Special Bulletin on these steel base floats. 1406 Bends, Coils, Fittings s^iSullme TO HtSK PROGRESS Ladish Co., Cudahy, Wisconsin . Controlled Quality FORGED AND SEAMLESS WELDING FITTINGS Complete range of types, sizes and materials DISTRICT OFFICES: Atlanta, Buffalo, Chicago, Cleveland, Havana. Houston. Los Angeles, Mexico City. New York, Philadelphia. Pittsburgh. St. Louis. St. Paul, San Francisco, Tulsa In Canada . . . LADISH CO. OF CANADA LTD., Brantford, Ontario Standardizing on Ladish assures unrestricted selection in meeting your entire fit tings requirements . . . for the Ladish fittings line is complete in types, sizes, pres sure ratings and material including carbon, alloy and stainless steels, aluminum, brass and other non-ferrous alloys. WELDING FITTINGS -- Size Ranges Given in Inches DESCRIPTION STD. EXTRA SCH. XXWEIGHT STRONG .160* STRON 90 Elbows Long Rad. Short Rad. Reducing 4-36 1-30 2x1 12x6 4-36 14-30 2x1 12x6 1-14 1-8 45 Elbows Long Rad. 4-36 4-30 1-14 1-8 Long Rad. 180 Returns X-Long Rad. Short Rad. 4-30 1-2* 1-30 J-30 1-2* 14-30 1-12 1-8 Tees [Straight Reducing Outlet 4-30 4x4 30x16 4-30 4x4 30x16 4-12 lx| 12x6 1-8 1x4 8x34 Reducers Concentric ?x| Eccentric 36x20 Jx| 36x20 w lx| 12x5 8x34 Stub Ends Caps Saddles! Nipples Laterals- Sleeves! Crosses Lap Joint 90 & 45 4-24 4-24 1-30 1-30 1-12 1-8 2-24--Do not conform to I.P.S. 14-12 14-24 14-12 14-24 2-24--Do not conform to I.P.S. J--24 }--24 * Also available in a range of sizes in Schedules 30, 60, 80, and 120. t For reinforcement only. FLANGES -- Size Ranges Given in Inches DESCRIP TION Welding Neck Slip-On Lap Joint 1 hreaded Blind Socket Orifice Reducing Long Welding Neck 150* 300* 400* 600* 900* 1500* 2500* 4-24 4-24 4-24 4-24 4-24 4-24 4-24 4-24 4-24 4-24 4-24 4-24 4-4 1-24 4-24 4-24 4-24 4-24 4-24 4-24 1-12 {-24 4-24 4-24 4-24 4-24 4-24 F-34 1-12 {-24 4-24 4-24 4-24 4-24 4-24 1-12 i-24 4-24 4-24 4-24 4-12 4-24 1-12 f-12 4-12 4-12 4-12 4-12 4-12 5--12 4-24 4-24 4-24 4-24 4-24 4-24 4-12 SCREWED & SOCKET -- Size Ranges Given in Inches DE SCRIP TION 90 Ell 45 Ell Tee Eli Lateral SCREWED 2000* 4-4 4-4 4-4 4-4 3000# 4-4 4-4 4-4 4-4 6000* 4-31 4-34 1-34 4-34 4-2 1-14 i-2 4-14 HI SOCKET WELDING 2000# 3000* 4000* 6000* 4-4 f-4 4-4 M 4-4 M 1-4 H 1-4 M M 1-4 1-4 J-4 4-4 H 4-2 i-2 HI HI phngs Reducer Bushings Plugs Inserts -------- 4-1 4-* 4-4 J-4 H |-4 4-4 1-4 4-4 J-4 4-4 f-4 4-4 H J--4 H H H 4-4 1*1--4x1 For use with Scb. 40 80 & 160 Pipe 1407 Large O.D. Flanges and T.E.M.A. Flanges up to 160 in. Bends, Coils, Fittings Taylor Forge & Pipe Works General Offices & Works: Chicago 90, 111. (P. O. Box 485) Plants: Cameeie Pa.: Fnntnn Cali?.* fiory^Ind.; Hamilton Out., Can. TAYLOR FORGE WeldELLS District Offices New York: 50 Church Street Chicago District Sales: 208 S. LaSalle St. Philadelphia: Suburban Station Bldg. ' Houston: City National Bank Bldg. Pittsburgh: First National Bank Bldg. Loe Angeles: General Petroleum Bldg. San Francisco: 225 Bush St. Dallas: Mercantile Securities Bldg. ? Short Radius Return Beni FuU Branch Tee 90* Long Radius WeldELL 4S* WddELL Long Radius Return Bend Whatever your piping requirements the Taylor Forge line-- WeldELLS and Forged Steel Flanges--will meet them. The Taylor Forge line offers a wider range of type sizes and weights in a complete range of materials. Popular ranges are listed below; more complete ranges in the big Taylor Forge catalog. Write for the name of your nearby Taylor Forge distributor, who carries stocks of WeldELLS and Flanges. Typo of Fitting WeldELLS WeldELLS WeldELLS Return Bends Return Bends Tees Tees Reducers Caps Stub Ends Saddles Sleeves Welding Fittings--Range of Sizes Descrip Standard tion Weight Extra Strong 90" Long '-30* '-30' Radius 90 Short l'-24' l'-24' Radius 45" Long '-30* '-30' Radius 180 Long '-30' '-30' Radius 180" Short l'-24' l'-24' Radius Full '-24' '-24' Branch Reducing l'xi'xr l'Xl'XK outlet 16'X16'X6' 24'X24'X10' Concentric i'xr rx' & Ec- 30'X24' 30'X24' centric l'-24' l'-24' Lap Joints l'-24' 1'--24' 2'-24' -- Welding 2'-24' -- Sched ule 160 '-24' l'-8' '-12' '-12* l'-8' _ __ -- _ -- -- -- Double Extra Strong '-8' r-s* '-S' _ l'-8' l'-S* _ rxr 8*X3' l'-8' l'-8' -- -- Forged Steel Flanges--Range of Sizes Welding Neck Slip-On Lap Joint Threaded Blind Socket Type Reducing (Threaded and Slip-On) Onfice 150 lb. '-24' '-24' '-24' '-24' '-24' '-24' 300 lb. '-24' '-24' '-24' '-24' '-24' '-24' 400 lb. '-24' '-24' '-24' '-24' '-24' -- 600 lb. '-24' '-24' '-24' '-24' '-24' 900 1500 lb. lb. '-24' : '-24' '-24' '-12' '-24' '-24' '-24' \0-Y2T '-24' '-24' ---- 2500 lb. '-12' '-12' '-12' '-12* -- '-24' '-24' '-24' *-24' *-24' *-24' '-24' -- l'-24' l'-12' l'-12* l'-12' Threaded Flange 1408 Bends, Coils, Fittings Pipe Welding Specialties Tube Turns, Inc. General Offices and Factory: Louisville 1, Ky. TRADE MARX DISTRICT OFFICES: THAOE MARK New York, 150 Broadway................. Rector 2-7844 Tciaa, 420 Wright Bldg..........................Phone 2-9193 Philadelphia, Broad Street Station Bldg. Atlanta, 1605 Atlanta Federal Savings Bldg. Rittenhouse 5-0722 Walnut 7310 Pittsburgh, 3001 Grant Bldg...........Atlantic 1-8848 Denver, Room 370, Silver State Bldg. Chicago, Suite 904, 600 S. Michigan Ave. Main 3261 Harrison 7-8526 Houston, 1709-11 Commerce Bldg........Charter 1668 Dallas, 4145 Grassmere Lane................. Justin 7213 Los Angeles, 2417 E. 24th'Street........ Jefferson 8257 Midland, Tex:, 606 West Watson San Francisco, 2611 Russ Bldg.......Garfield 1-2594 In Canada: Tube Turns of Canada, Limited, Chatham, Ontario DISTRIBUTORS IN PRINCIPAL CITIES In addition to carbon steel welding fittings listed here, the complete TUBE-TURN line embraces many alloys--types 304, 347 and 316 stainless, carbon moly and chrome moly steels, copper, aluminum, brass, Monel, Inconel, nickel and wrought iron. Dimensions and engineering data are included in TUBE-TURN catalog and Engi neering Data Book No. 211, sent on request. Straight Tee 90 Short Radius Elbow Radius Elbow 90 Long Radius Elbow TUBE-TURN SEAMLESS WELDING FITTINGS--RANGE OF SIZES light Gauge DESCRIPTION WSatearindgdh*t SEtxrotrnag uSlceh1ed60 DSEotrxaotrbnalge NoaL Size PSiizpee BROWS--90 long Rodim *'-42' *'-42' l'-J2' *'8' 4'-24' *'-12' aeows--90 Short Rodim l'r42' l*'-42' ELBOWS--45 U*g Radius *'-42' **-42' 1'-I2* %'-8' 4'-24' *M2' RfclURNS--1 SO long Rodim *'-30' *'-30' '-12' 2'8' 4'-24' %'-12' RETURNS--1 80 Short Rodim IP-30' l*'-30' RERTUoRdNimS--180 Extra long 1'-2*' 1'-2*' TEES--Straight *'-30' *'-30' *M2' *'-8' TEES--Reducing Outlet *'-30' *'30' *'-2' *'-0' REEDcUcCeEnRtrSic--Concentric ond %30''x*2*4'- %30''xx2*4'-' %12''xS*'' *B''x3**'' caps Cop STUB ENDS--Lap Joint %'-3' *'-34' l'-12' 1 '-8' *'-24' *'-24' SADDLES 2'-24'* LATERALS--Straight 1 '-24' 1 '-24' LATERALS--Reducing-on-run l'-24' 1 '-24' CROSSES--Straight and Reducing %'-24' *'-24' RINGS--Welding, Grave Type %'-24' 1'-24' 1%'-8' RINGS--Welding, Ridge Type *M2' *'-12' SLEEVES--Welding 2'-24'* I| p*SipbeKtirseatdhdklfecn*eetsned*.sleeve* are for external reinforcement only, fbey do not conform to iron Blind Flange TUBE-TURN FORGED STEEL FLANGES--RANGE OF SIZES DESCRIPTION Po1r5a0di Po3u0n0ds Po4a0a0ds Po6a0n0d* Po90m0dt P1o5a0a0dt P2o5a0nd0s Welding neck sup-on LAP JOINT **-24* **24* **-24> *****2244**1t **-24* **24* **-24*t **24* **24* **24** **24' *M** **24* **24' **-12 **24** **12* THREADED BUND **24* **-24* *-34' *'24* **-34*t **-24*t **24* **24* **24** **12*1 *M2* **24** **34* **13* SOCKET TYPE v*w %*-3**t **3** JitTip RESDttUp-COINaG--Threaded or ORIFICE--Threoded V-M1 **24* %*-4*t 1M4* 4*-12* **-4# %M4W 4*-12* 3*-12* %M4* i*.ir ORIFICE--Slip-Oe IM4* ORIFICE--WeMbtfl Neck 1M41 4*-12* 1*-12* 3*-12* 1*-12' toeaAeet eo rixe* thru in' m a* for 1500 tb. ftattge*. Gapped Flange "W" and "TUBE-TURN" are trade marks of Tube Turns, Inc. 1409 Straight Lateral Straight Cross Threaded Flange Controls and Instruments Alco Valve Company ENGINEERED REFRIGERANT CONTROLS 851 Kingsland Avenue, St. Louis 5, Mo. New York Office: 55 West 42nd Street Chicago Office: 4534 North Broadway THE COMPLETE LINE OF REFRIGERANT CONTROLS ALCO THERMO EXPANSION VALVES: for automatic control of liquid refrigerant on all types of refrigeration and air conditioning systems. Capacities--from frac tional tonnage to 220 tons Freon-12, 350 tons Freon-22. Low temperature valves for -40F to -100F. W Imiii BIT d iM Im Controls and Instruments Barber-Colman Company Automatic Temperature Controls Rockford, Illinois THERMOSTATS OUTDOOR RESET CONTROLS Type 402 totth pres sure limiting feature Type TK *'$ voices in 1" Type TCL Type TR-- Multi-Outlet ALCO SOLENOID VALVES: for all types of service. For Liquid: Freon-12 up to 75 tons; 90 tons Freon-22. For Suction: Freon-12 up to 10 tons; 15 tons Freon-22. For brine, water, gas, air and steam. Type St Type MS Type RS ALCO AMMONIA CONTROLS: Solenoid Liquid yalves--up to 172 tons. Solenoid Suction Valves--up to 28 tons. Thermo Expansion Valves--from fractional ton nage to 125 tons. Automatic Expansion Valves--from fractional tonnage to 60 tons. Type M91F Type UQ ALCO SUCTION LINE CONTROLS: Type 3 with Strainer Type EPR--,for aU refrigerants, with connection sizes up to 0 in. Types 771-772-SUCTION PRES S URE REG ULA TORS--HOLD BACK VALVES--prevent motor overload. Freon-12, Preon-22, Type 760 "EVAPOTROhM --Pressure Regulator-- FFrreeoonn--Iltt----^Hi ton, M&P Chloride ALCO ALSO MAKES: Constant Pressure Expansion Valves--Liquid and Suction Line Strainers--High Pressure Float Valves--Electric Float Switches. 1410 Single, duplex, two-stage Room Thermo stats; single, two-stage Remote Bulb Thermostats; Humidistats; Room and Remote Bulb Microtherms. MOTOR-OPERATED VALVES For floor and ceiling panels, convectors, and baseboards, Dual Bulb Thermostats and Adjustable Ratio Controls are applicable to oil and gas burners, stokers, or as proportioning controller. ECONOSTAT CONTROL MOTORS Regular, heavy-duty, oil-submerged motor-operators on all conventional single- or double-seat valves, used in "Si sir conditioning systems, most industrial processes. A modern, simplified, effective methc r quality installation of electr temperature contri- Cabinet or pan oard serves as central junction poii i r entire wiring system, providii using for accessories--relays, switche ansiormers, etc. Prewired internall l !ltrl Center" comes onto job pr ec.kec` for performance, fitted wil with red term*na? strips correspondir Do " iflu,T?*,ered wires and component -I, 'n easier installation, easii aPpearance. 'owered costfb imPTM< ECONOSTAT ZONE CONTROL The Econostat provides outdoor-indoor zone control for almost any type of multiple-occupancy building, and pro duces increased comfort and fuel economy. Exceptional flexibility in a compact, easily installed unit. CONTROL MOTORS For damper operation and other control functions. Regular, heavy-duty, oilsubmerged types (latter featuring ad justable speed and proportioning mecha nisms). Also Program Switches. 1411 iip s w w Controls and Instruments Cam-Stat, Incorporated Division of The Paul Henry Company 11831 W. Olympic Blvd. Los Angeles 64, California District Offices In All Principal Cities . AUTOMATIC TEMPERATURE CONTROLS These compact warm air furnace controls are available, as shown below, for integral mounting on the furnace, and also in conduit housings to meet 17.L. requirements for plenum or duct mounting. Any one of the controls below is available in combination with any one of the other controls, complete in a conduit housing. Extreme sensitiv ity is obtained through the use of a low mass bimetal actuator. This insures uni formly accurate control results even with high rates of temperature change. FAN CONTROL FIXED LIMIT CONTROL Model No. PUSA Specification: Range--80 to 130 F. Dif ferential--15 F. (Fixed). Rating--^hp at 120 or 240 volts A.C. Equipped with manual summer fan switch. Model US-7A Specifications: Fixed cut-out and dif ferential to manufacturer's requirements. Rating--90 volt-amps at 30 volts A.C. ADJUSTABLE LIMIT CONTROL FAN CONTROL Model LSSSA Specifications: Range--170 to 200 F, or to manufacturer's requirements. D>fferential--Fixed anywhere between 15 and 50 F. Rating--90 volt-amps at 30 volts A.C. RESET LIMIT CONTROL Model No. Fll-IA Specifications: Range--80 to 130 F. Differential--15 to 30 F. (Adjustable). Rating--i hp at 120 240 volts A.C. Equipped with manual summer fan switch. Model No. L2S-9A * Specifications: Fixed cut-out to manu facturer's requirements. Equipped with push button to reset after cut-out. R*" mg--90 volt-amps at 30 volts A.C. 1412 Controls and Instruments Combustion Control Corporation Flame Failure Safeguards For Oil and Gas Burners Photoelectric Smoke Indicators 718 Beacon St., Boston 15, Mass. Atlanta--Chicago--Cleveland--Dallas--Hartford New York--Philadelphia--San Francisco--Washington, D. C. District Offices in all Principal Cities FIREYE SYSTEM FP-2--FLAME FAILURE PROTECTION AND PROGRAMMING FOR AUTOMATIC BURNERS Type IfSPTi Fireye System FP-2 provides com plete automatic starting and operating flame failure protection for industrial and commercial gas or oil burners and gas/oil combination burners. The single scanner visually supervises both main and pilot flames ana does not allow the main fuel valve to open unless the pilot flame has been established. The system causes immediate shutoff of all fuel after a flame failure. Programming Control programs the operating sequence of blower and/or burner motor, ignition system, fuel valve, and modulating motor. It pro vides a purge period before and after each firing period. System FP-2 includes a safe-start fea ture whereby component failure within the Fireye equipment or any unsafe condition will prevent burner startup. FIREYE SYSTEM FP-4--FLAME FAILURE PROTECTION FOR MANUALLY AND SEMI-AUTOMATICALLY IGNITED BURNERS Fireye System PP-4 provides starting and operating protection for manually or semi-automatically ignited gas, oil, pulverized coal or combination fuel burners. Scanner continually "sees" pilot flame, main flame, or both, causes immediate shutoff of all fuel valves in the event of flame failure. Manual re start is required after safety shutdown. System FP-4 includes a safe-start feature whereby component failure within the Fireye equipment or any unsafe condition positively prevents burner operation. The control provides direct panel board connections for operating and limit switches, low fire start switches, fuel-air flow switches, oil temperature thermometers, etc. FIREYE SMOKE INDICATORS AND RECORDERS Fireye Smoke Indicators and Re corders measure smoke density in chimQeys to aid in keeping within legal limits and provide an overall check of combus tion efficiency. Equipment consists of light source, Photoelectric scanner, and control/ indicator. Light source and scanner are mounted on opposite sides of the stack 0r breeching. The indicator and smoke recorder (if desired) may be mounted at any convenient location. 1413 Scanner Type 47FU1 Indicator Type Z1LH6 Controls and Instruments The Electric Auto-Lite Company INSTRUMENT AND GAUGE DIVISION Department HV TOLEDO 1, OHIO U\\YV'UUrf NEW YORK CHICAGO SARNIA, ONTARIO TEMPERATURE INDICATING AND RECORDING THERMOMETERS MODEL 1000 RECORDING 4- THERMOMETER Temperature cycles are permanently charted by this latest addition to the Auto-Lite line of temperature recorders. Has evenly calibrated, 6-in. chart; at tractive die-cast case. Various standard chart ranges from minus 40F to plus 550F. The style shown is wall mounting type, with capillary tubing for remote, eyelevel reading. Also available with port able case with capillary and portable self-contained. Obtainable with cycle indicator for refrigeration. Choice of 24-hour or 7:day mechanical chart rota tion. MODEL F-l INDICATING THERMOMETER -* Designed to facilitate systematic tem perature observation for air condition ing, refrigeration or heating applica tions. Large, easily read dial, evenly calibrated and fully compensated for temperature changes at the indicating head. Adjustable to 3 positions. Choice of temperature ranges from minus 40 F to plus 750 F. Available with elec tric alarm contact at small added cost. MODEL "G" INDICATING 4- THERMOMETER These thermometers have the same effi cient one-to-one ratio, solid liquid-fi"" movement as Model "F" with evenly calibrated scales. Capillary tubing fr remote reading or rigia stem. Send for Catalog describing styles and types of Auto-Lite Thermometers. 1414 Controls and Instruments Field Control Division of H. D. Conkey & Company, Mendota, 111. Manufacturers of FIELD DRAFT CONTROLS FIELD BAROMETRIC DRAFT CONTROLS FIELD TYPE M: For automatic heating . equipment, designed to assure finer performance, greater fuel economy, through highly accurate control of drafts. Available in sizes from 6 in. through 24 in. for pipe diameters of 6 in. through 25 in. Features "Rocking Chair" gate action, off-center gate mounting, sidewings, extended housing. Widely used in the heating industry. FIELD SCOTTY: Available in pre-set or adjustable models, for use on space heaters and ranges. Adjustable model is adjustable for high, medium or low draft. Pre-set model is pre-set at fac tory to manufacturers' specifications, j-n 6 in. and 6-7 in. sizes.for space heaters and ranges with 6 in. or 6-7 in. outlets. For horizontal or vertical installation. 26 gauge Tee, and stub, 24 gauge ring. The choice of leading manufacturers. FIELD BAROCHEK: Combination barometric draft control and check damper for use on hand-fired furnaces. Will provide fully automatic control of stack drafts, or can be manually checked in open position. Also ideal as part of a damper motor set. Available in 7 in. through 24 in. sizes for 7 in. through 25 in. pipe diameters. Reduces fire hazard, cuts fuel consumption, reduces furnace tending and furnace wear. . FIELD "MG" DOUBLE ACTING: For commercial gas fired heating plants. Double acting gate opens inward to regulate up-drafts, and outward to re lieve down drafts. Highly sensitive. Opt'onal safety switch closes main gas valve in case of prolonged down draft, k?3 Providing lull protection. Availan'e in 10 in., 12 in., 16 in., 20 in. and . sizes. Illustration shows up-draft view. ' Fulton Sylphon Division ROBERTSHAW-FULTON CONTROLS CO. Knoxville 1, Tenn. Sales Representatives in Principal Cities Manufacturers of Sylphon Automatic Temperature Controlling Instruments and Packless Expansion Joints HOT WATER SUPPLY No. 999 Temperature Regulator controls temper ature of liquids. Particularly suited for storage water heaters and for all indus trial processes requiring accurate tem perature control. Stainless steel frame for minimum heat conduction. Large size Sylphon Bellows provides added power. Self-operating. Yalve sizes from in. to 4 in. Temperature ranges start at 40 F, up to 420F. Bulletin HVG-E. SYLPHON PRESSURE REGULATORS phon Automatic Valves--no.wiring, pip ing or auxiliary equipment is required. These valves answer the demand for an inexpensive means of providing accurate, dependable space temperature control in rooms, sections or throughout large buildings, new or old. Similar type valves for concealed radiation--get Bul letin HVG-E. Sylphon No. 890 Radiator Control Valve For either exposed or concealed radia* tion. Similar in appearance and action to other Sylphon Automatic Valves, but operated by an electric wall thermostat. The closing of the thermostat circuit energizes a low voltage electric heater coil surrounding a bulb containing a vola* tile liquid. This liquid expansion causes pressure on a bellows in the valve head operating the valve. This provides radi ator valve control from a remote loca tion, permits regulation of several radia tors from a single thermostat, enables a time switch to be installed, if deshred, offers effective zone control of large areas at a fraction of the cost of conven tional motor-operated valve systems. Bulletin HVG-E. Dependable pressure regulators for air, gas, water or oil. Also recommended as air or hydraulic "bellows motor" control valves. ; All metal construction . . . stainless steel frame. Spring adjusted type. Sizes in. to 4 in., inclusive. Types for initial pressures up to 150 lbs and for controlled pressures up to 55 lbs. Bulletin HVG-A. Sylphon No. 7 Temperature Control A self-contained, self-powered regulator for controlling unit heaters, wall or ceil ing type radiators, heating coils in duct- SPACE HEATING CONTROL No. 885 Automatic Radiator Valve-- "TiP For exposed radiation. Small, neat, at tractively finished, adjustable to room temperature desired. Simply replace ordinary radiator valves with these Syl type heating systems, etc. Quickly in stalled, holds temperatures within close limits. Valve placed in steam line to one or a battery of heaters, thermostat mounted on wall or column. For use on regular heating pressures up to 15 lbsSimilar regulators. Nos. 7-2 and 7-3 for 75 lbs pressure and temperatures up to 170 F. Bulletin HVG-E. 1416 Fulton Sylphon Div. Controls and Instruments refrigeration CONTROLS No. 945-Z Regulator ranged to control any air conditioning system and to provide exactly the condi tions desired. Write for Bulletin SAC-850. The No. 928-H Regulator Adaptable wherever brine is used as the refrigerant. Latest development is a "freeze-proof" valve (illustrated) on the popular Sylphon No. 945-Z Regulator.. Bulletin HVG-D. PACKLESS EXPANSION JOINTS No. 110-M Sylphon Expansion Joint The Sylphon Packless Expansion Joint eliminates expensive construction, non revenue producing space. No leaks or repairs, no repacking. Use No. 110-M for steam lines; No. 111-M for water lines. Sizes % in. to 3 in., inclusive. Bulletin HVG-65. NO. 96066 SYLPHON EXPANSION JOINT Simple, compact yet highly sensitive. Suitable for modulating control of air temperatures in ducts. Bulb is construc ted of numerous coils of copper tubing giving sensitivity to the slightest tem perature variation. Packless valve eliminates service problem and makes this regulator ideal for-installation in in accessible locations. Suitable for steam pressures up to 15 lbs; other types availa ble for pressures up to 75 lbs. The Sylphon No. 889-C Regulator Used on hot water lines, a simple, com pact means for absorbing expansion of "baseboard" radiation, finned convec tors, horizontal supply lines, etc. A twoply Sylphon bellows absorbs expansion, prevents noise, pipe strains, leakage. Complete factory assembled unit. Easily installed or removed. Sizes % in. to 2 in., inclusive. Bulletin HVG-E. HEATING AND AIR CONDITIONING CONTROL Almost any type of heating, ventilat ing or air conditioning system can be advantageously controlled wholly or in part by Sylphon Regulators. Basic ad vantages of Sylphon Controls are: . Modulating--Maintains ideal condi tions--not continually correcting too hot, too cold, too humid or too dry conditions. Compensating--Many Sylphon Regu lators offer compensating control, auto matically raising their low limit setting at a predetermined rate as outside tem peratures fall. Sensitive--Close operating temperadifferentials. Quick response. Simple--in design. Rugged. Construction--To give years of satisfactory service. Adaptable--Any one of many combina tions of Sylphon Instruments can be ar A modulating, dual-function regulator for control of duct heating and ventilat ing systems--two independent valves in a single body. Adjustable Thermostat "A" governing Valve "D" functions to maintain room temperature from temperature of re circulated air. Adjustable Thermostat "B" acts as a low-limit ducstat control ling Valve "E" to maintain minimum discharge air temperature. Bulb "C" compensates Bulb "B" to maintain even discharge air temperature irrespective of demand. Compensated Thermostat "B" can also be furnished to raise its setting at a predetermined rate with falling fresh air temperatures if desired. Suitable for steam pressures up to 15 lbs. The Sylphon No. 889-C7 Regulator The No. 889-C7 regulator has a wall type adjustable thermostat that is placed in the room or space to be controlled. This thermostat "A" operates upper half of the regulating valve. Otherwise, same as No. 889-C regulator described above. 1417 Controls and Instruments GENERAL CONTROLS Jdanufacturers of Automatic Pressure, Temperature, Level and Flow Controls Skokie, Illinois Glendale, Calif. * Burbank, Cali! Factory Branch Offices in Thirty-five Principal Cities {A) Type T-70 (B) Type K-10 (D) Type B-SS-G (B) Typt KS-A (A) THERMOSTATS Compact, snap-action, Line or Voltage Thermostats. Functional beauty for ac curate, remote control of desired temper ature. Extends only J4 in. from wall. Streamlined stainless cover, sensitive to slightest temperature change, ivory plastic base. (B) K-10 MAGNETIC LEVER VALVES Provides six times more power than ordinary solenoid valves. Controls air, gas, water, light, heavy oils, steam. Positive opening, complete shut-off, packless, hum-free. Available for any voltage, a.c. or d.c., in sizes up to 134 in. I.P.S., port sizes up to % in. (D) SLOW OPENING GAS VALVES New combustion control afforded by these diaphragm-controlled gas valves. Governor model regulates fuel supply to burner in direct ratio to steam pressure, eliminating hunting aspect. Available 1 in. to 6 in. I.P.S. (E) MAGNETIC GAS VALVES Versatile, two-wire, straight magnetic current-failure valve. Packless. Insures tight shut-off indefinitely. Humless. Size range % in. to 6 in. I.P.S. Operating pressures up to 10 lb. Voltages and fre quencies a.c. or d.c. Quiet, positive, trouble-free. Available in explosionproof housing. General Controls Controls and Instruments Simplify valve control installations. Two-wire, current failure, electric-hy draulic operation. Ample motor-driven power, slow opening and closing move ment. G-l Series, designed for low-pres sure steam, hot and chilled water circu lating systems. G-2 and G-3 Series for high pressure applications. (H) REFRIGERANT CONTROLS Magnetic Stop Valves Piloted, two-wire current failure, high-pressure, packless. Handle large capacities with minimum pressure drop and loss. Tight Shut-off. Operates on air, steam, water, and re frigerants. (I) *hi-g MAGNETIC VALVES Designed for positive operation on air craft, trucks, tractors, tanks, graders, ships, and other moving equipment. Handle all fluids, vapors and gases on anything that rolls, floats or flies at pres sures up to 3000 lb or more. Packless, two-wire, current-failure type, available normally open, normally closed for inter mittent or continuous duty. Gas safety control--thermocouple in pilot flame closes control, circuit auto matically through relay to hold gas valve open. Gas valve shuts off when pilot is extinguished, prevents gas escape. Thermocouple adapts to pilot burners. Pilot generator models for Jong couple lengths or operating multiple controls. (L) THERMAL EXPANSION VALVES Type V-200 with new selective capacity cartridge provides instant sizing adjust ment. Only one valve required for full capacity range in each body size at all back pressure or suction temperature ranges. For Freon, Methyl Chloride or Sulphur Dioxide. (M) THERMOPILOT VALVE AND GAS COCK SAFETY VALVE Manually reset, electromagnetically holds valve open with current generated by thermocouple, subject to heat of pilot flame. Automatically shuts off gas if pilot goes out. Type MR-5 combines manual gas cock with thermopilot safety valve. Available in % in. to 1J4 in. (C) BX-G9 GAS ACTUATED PACKAGE SETS (F) Type V-110 (F) MANUAL RESET VALVES No outside current required. Operates on all types of gases. Safe, quiet, de pendable. For all gas-heating appli ances. Set consists of a PG-9 500 milli volt pilot generator, a B-60 gas control valve, a T-70 snap-action thermostat, thermostatic cable and vent tubing. Everything needed in convenient pack Equipped with manually-reset electro- magnetically-held valve operator. Cur rent flowing to operator permits manu opening by turning valve wheel at siaeCurrent failure releases operator &U? ing valve to close. Trip-free mechanis won't open under unsafe conditions- Closed, valve must be reopened ma age for remote gas control. ually. 1418 t-Y) SA < SY Strainerj (N) STRAINERS {K) Type A-100 (J) Type RS-100 Rday (J) RELAYS AND TRANSFORMERS pe RS-100 handles single phase motor oads up to 1 hp or heating loads up to 1 k\\. Combines double-break relay and integral transformer. Normally pen; large double-break contacts. Two*re control circuit; maximum holding i rrent 9 4 amps. Furnished with conduit connections and low voltage a.c. only. of mT*rf^e'mar^--"hi-g" indicates positive ability to oiion or acceleration. Protects automatic regulators or valves from pipe scale, other foreign matter. Assures proper seating, closing of valve. Prevents leakage. Convenient cleaning or blowoff without breaking line. Monel screen. OTHER GENERAL CONTROLS ITEMS . IMMERSION THERMOSTATS COMBINATION FAN AND LIMIT CONTROLS . STEAM PRESSURE, VAPOR AND VACUUM CONTROLS TEMPERATURE CONTROLS . LOW WATER CUT-OFFS lotion in any position, regardless of vibration, change 1419 Controls and Instruments Henry Valve Company MELROSE PARK. ILLINOIS (A Chicago Suburb)" ' . HENRY PRODUCTS FOR REFRIGERATION. AIR CONDITIONING. AND IN DUSTRIAL APPLICATIONS: CONTROL DEVICES. VALVES. STRAINERS DRIERS. FITTINGS. AND ACCESSORIES. sure refrigerants. Approved under safety codes. FERROUS TYPE--For ammonia. Approved under safety codes. DRIERS Filled with silica gel--other de hydrants on special order. Balanced-Action Diaphragm Packless Valves STANDARD TYPE Two-way, branch shut off, and angle types--flare or solder connections. Hand expansion, purge and charging types also available. Forged brass body and bonnet, portsin-line, non-directional. Back seat and ball check permit diaphragm inspection and replacement under pressure. Stock sizes Yi thru Ys" flare; Yi" thru \Ys" O.D. solder; Ys thru Yi" F.P.T. BLUE BANTAM TYPE--Two-way line shut off valves, flare or solder connec tions. Contain same field proven fea tures as STANDARD line except that diaphragms cannot be inspected or re placed while valves are under pressure. Stock sizes Yi" thru Ys" flare and solder. TYPE 705--Brass shell, forged brass end caps with integral fittings--silver brazed joints. Dehydrant capacity 10 to 32 cu in. Sizes, Yi* thru Y>" flare.i TYPES 77, 78 and 79 cartridge driers with side outlet, safety disc, cartridge retaining spring and distortion-proof ac cess flange. Dehydrant capacity 12 to 500 cu in. Sizes YY thru 2Ys' O.V. sol der. Can be converted to strainer by use of strainer screen cartridges. STRAINERS WING CAP PACKED VALVES Bronze with solder connections in globe and angle types, Ys thru Ws" O.D.; semi steel with F.P.T. connections in globe and angle types, sizes Yi thru 2"; semi steel with bolted bonnets and square companion flanges with brass tailpieces for O.D.S., thru 5Y". Flanged valves also available with steel tail pieces for welding to pipe 1 Y\" to 5* IPS. TYPES 891 and 892. Screen area 11 and 25.5 sq in. respectively. Sizes Vi thru Ys" flare and Ys" thru Y" O.D. solder. TYPE895Brass plated steel "Y" strainer, welded construction, forged brass end caps. Distortion-proof access flange- Screen area 23 to 150 sq in. biz Ys" thru O.D. solder. . RELIEF VALVES DIAPHRAGM TYPE--For Sold, by refrigeration jobbers. low-pres Free Catalogs. 1420 Writs f0' Controls and Instruments Hubbell Corporation Mundelein, Illinois C. & S. EQUIPMENT CO., INC. 2103 San Pedro St, Los Angeles 11, Calif. MASON EMANUELS CO. 91 Dearborn St., Seattle 4, Wash. Designers and Manufacturers of Automatic Control Valves for All Refrigerants Type SA'S, SF-6 Type 8A-6, SF-6 Type SA-7, SF-7 Back Pressure Regulating Valves are of the conventional type used to maintain a constant evaporator pressure. Combination Back Pressure Regulator and Stop Valves. This regulator is of the conventional type used to maintain a constant evaporator pressure and the addition of a small electric pilot valve built into the head, makes it a suction stop valve. Type DSA-9, DSF-9 1* The Type "T s__u_c_t_io__n__s_t_orp v_a__lv_e_wis any two evaporator pressures and will used where automatic suction line con automatically change from one to the trol is required. It is operated by high other by the opening or closing of the . pressure gas and its construction makes electric pilot valve. a tight closing valve and its dependabil- uy far surpasses the conventional mag netic stop valve. 3. The SAC-6 and SFC-6 valves are of the compensating type and are used where a constant temperature is desired in the 2;,T^e DSA-9-DSF-9 is a dual regulator medium being cooled. These valves will j'nich will control evaporators with increase or decrease the evaporator pres ".o. lad conditions requiring different sure to compensate for the increase or ^rigerant temperatures. The dia decrease of the cooling load. Operated phragms in the dual head may be set for with air or electricity. Solenoid Valves from | in. to 2 in. 1 qe/tliuiis..i.v.e f.or il,iqui.d.s and. gases with. com position seat discs readily renewable, hn u any electrical characteristics, eitL ,n 8tem standard, with r 8crewed, welding flanges or copper t.ube conne--c--t-i-o-n--s--. Strainers in all sizes for liquids and gas with very large screen areas and ar ranged to bolt directly to valve or with screwed, welding flange or copper tube connections for installation wherever strainer is necessary. for Va*Ves ^ave built-in opening stems, which eliminates the by-passes usually used rA_man>ual operation. With either screwed, welding type flanges or copper tube ^ Sections, in sizes from % in. to S in. inclusive. r f0r complete information on these and our many additional Refrigeration Controls and Accessories. . 1421 Controls and Instruments Johnson Service Company AUTOMATIC TEMPERATURE AND AIR CONDITIONING CONTROL General Office and Factory - - - - Milwaukee, Wis. . Direct Branch Offices in Principal Cities ' Johnson Temperature Regulating Co. op Canada, Ltd., 3615 Danfobth Avb., Toronto 13, Ont. Halitax, N. S. Montreal, Qub. Winnipeg, Man. Caloabt, Alta. .Vancouver, b C. PRODUCTS AND SERVICES Manufacturers, Engineers and Contractors for automatic temperature and humidity control systems applied to all types of heating, cooling, ventilating, air conditioning and industrial processing installations. Space Control--Automatic control of room temperatures and humidities, applied to convectors, radiators, radiant heating, unit ventilators, unit heaters and heat delivery ducts. Also, Johnson "Duo-Stats" to maintain proper relationship between outdoor and heating system temperatures for groups of radia tors or "heating zones." A complete line of controllers for air conditioning systems, heating, cooling, humidifying, dehumidi- fying. . Process Control--Automatic temperature and humidity con trol for every range required in manufacturing and industrial processing. Thermostats, valves and dampers applied to tanks, dryers, vats, kettles, curing rooms, coolers, kilns, etc., in textile, rubber, pulp and paper, petroleum refining, meat packing, dairying, baking, sugar refining, brewing and distill ing, tanning, candy making and other industries. Nation-wide Service--Johnson sales engineers, and trained installatio men available at all branches listed above. None is an age t, jobber, or part-time representative. All are salaried employees, devoting their efforts to the interests of the Johnson Service Company and its customers. Send for Bulletins. JOHNSON THERMOSTATS Room Thermostats--Proportional (gradual) or two-position (positive) action, maintaining temperatures within one degree above or below point of setting. Various covers allow wide selection of adjusting features, guards and mounting method. Red-reading thermometers with magnifying tube attached to covers. .. Insertion and Immersion Thermostats--Rigid stem or capil lary. Liquid-filled capillary systems for temperatures which are measured at point remote from location of operating mech anism. Various types of bulbs. Standard connecting tubing 8 ft long; 15, 25, 35 or 50 ft on special order. Thermometers--High grade insertion or immersion ther mometers to measure temperatures in ducts, tanks, etc., with red-reading mercury column in heavy lens glass tube and 9-in. scale. Insertion thermometers have patented adjustable tilt ing feature. Dial thermometers with liquid-filled capillary elements. Special Controllers--For applications in industrial processes. "Record-O-Stat," combination capillary temperature control ler and recorder. 12-in. chart and liquid-filled capillary sys tems. Single or duplex type, the latter controlling and record ing wet and dry bulb temperatures. Pressure Regulators-- Pressure ranges 30 in. of vacuum to 250 psi pressure. Types and sizes for required pressure range and for medium to be controlled: Air, water, steam or freon. Liquid Level Regula tors (Float type)--Control within extremely close limits. Mounted through wall of containing vessel by stem with 1 in. pipe thread. Floats of copper, stainless steel or special alloys. Static Pressure Regulator--Measures variations in pressure from .009 in. to 3 in. of water. Also used as differential regula tor, measuring difference in pressure between two chambers. 1422 Single Room Thermostat T-400 "Dual" Room Thermostat T-460 Room Humidostet H-107 Sylphon Valve for Convertors V-J53 Johnson Service Company Controls and Instruments Rigid Stem Immersion Thermostat T-804 Submaster Capillary Thermostat T-901 m V.J0S Gk&e Valve with Pilot Positioner Submaster Thermostats--An important development for industrial applications and air conditioning. Available in various types of controllers where readjustment must be made from a remote point. Johnson Sensitivity Adjustment--A distinctive feature af fording convenient means of adjusting the sensitivity of ther mostats and humidostats, on the job, balancing "time-lag** with respect to capacity of conditioning apparatus. "Hunt ing** and temperature fluctuations prevented. Available on Johnson proportional action insertion and immersion thermo stats, insertion humidostats, capillary thermostats, pressure regulators and certain room thermostats and humidostats. JOHNSON HUMIDITY CONTROL Johnson Humidostats--Automatically control supply of moisture delivered to air by a humidifier or other means, main taining constant relative humidity. Available in room and insertion patterns with various elements, the most sensitive controlling within 1 per cent at relative humidities as high as 95 per cent at 100 F. Humidostatic elements are wood cylinder, bi-wood strip, bow-wood, horn, bair or animal membrane. Johnson ^Humidifiers--"Steam grid** type (perforated pipe supplied with low pressure steam) or pan type with copper evaporating pan, brass heating coils and float control. JOHNSON VALVES Johnson Diaphragm Valves--Simple, rugged. Diaphragms of special molded rubber, resistant to age and oxidation, op erate valve stems against pressure of dependable springs. Available also with Sylphon seamless metal bellows. In standard sizes and patterns including compact valves for con . vectors and unit conditioners. Normally open (direct acting) or normally closed (reverse acting). Three-way mixing and by-pass valves, for steam, water, brine and other liquids and gases. Johnson "Streamline** Diaphragm Valves--With modulating discs and special internal construction. Smooth proportional control. Where maximum power is required for repositioning at slightest demand of controlling instruments, the larger molded rubber diaphragm valves are fitted with pilot posU tioner, independent of friction and pressure variations. JOHNSON DAMPERS AND SWITCHES Standard Johnson Dampers--Galvanized blades in flat steel frames with adequate bracing to form rigid assembly. Black lacquer or special corrosion-resisting finishes. Angle iron frames optional. Special Dampers--Galvanized iron frames and monel metal, aluminum, copper or rust-resisting steel blades on order. Frames of same material as blades, if desired. Brass pins in steel bearings or ball bearings. Johnson Damper Operators--Similar in principle to valves. Seamless metal bellows or specially molded rubber diaphragm operates damper through suitable linkage. Johnson "Piston** damper operators afford long travel at full power. With or without pilot mechanism, as described for "Valves.** Johnson Pneumatic Switches--For operation of dampers and to place controllers in and out of service from remote points. Standard switchboards are Masonite. Ebony, asbestos, steel, polished oak and genuine or imitation marble on order. Various apparatus is mounted on special switchboards, including gradual, lever type and multiple-step switches, clocks, air pressure gauges, recording gauges, etc. `'ail Volt' Diaphragm V-108 Piston Damper Operator DtSl Proportioning Louver Damper D~StS 1423 Controls and Instruments Illinois Testing Laboratories, Inc. Room 516, 420 N. La Salle St.y Chicago 10,111= Precision Instruments for Every Industry The direct-reading ALNOR VELOMETER T YPE i-F Standard minimum get for heating and air conditioning air velocity measurements. The Alnor Velometer is an instantane ous, direct-reading air velocity meter designed for convenient, rapid deter mination of air velocities in air condi tioning, heating and ventilating, and exhaust systems. It gives instantaneous direct readings in feet per minute, with out timing, calculations, or reference to tables or charts. Accurate information on performance of equipment, duct sys tems, etc., can be obtained with a few moments inspection with the VELOM ETER. It can be effectively used to locate drafts and leaks around windows and doors, or in duct systems. Alnor Velometer, Jr. A miniature, di rect reading Velometer--4 in. high, 3 in* wide, l- in. deep. Weight, 8 oz. Accu rate, strong.. Available in single and double scale ranges: 0-200 to 0-2500 fp* Bulletin 725. The Alnor Velometer is built in several standard ranges from 20 fpm to 6000 fpm, and up to 3 in. static or total pressure. Special ranges available as low as 10 fpm and up to 25,000 fpm velocity and 20 in. pressure. Alnor Thermo-Anemometer. For accu rate measurement of low air velocityCompact, direct-reading, battery oper ated, self-contained, portable. Scale 6 ib. Meter ranges: 0-600 fpm and double range 0-300/100-2000 fpm. Accurate reading38 low as 5 fpm. Temporary Bulletin 913-A ^ 1424 Controls and Instruments Leslie Co. 266 Grant Avenue Lyndhurst, New Jersey REGULATORS and CONTROLLERS for the Regulation and Control of Pressure, Temperature, Flow and Liquid Level.* mu ESTABLISHED 1900 LESLIE COAST-TO-COAST SERVICE In all principal industrial centers LESLIE factory-trained engineers are available to help with any control prob lem involving steam, liquid, air or gas. Look for LESLIE REGULATORS under "Valves,, or "Regulators" in your classi fied telephone directory. INTERCHANGEABILITY--All internal parts of LESLIE Regulators are dimen sionally interchangeable and have maxi mum interchangeability in all sizes and classes. Reducing Valve Class L-3 Temperature Regulator . Class T LESLIE EXCLUSIVE FEATURES--at ho extra cost! Stellited Seat Rings . Hardened Stainless Steel Main Valves, 500 Brinell Corrosion Resistant Springs Hardened Stainless Steel Cylinder Lin ers, 500 Brinell. Supplied as standard equipment. Self-Cleaning Strainer Pump Governor Class PR LESLIE PRESSURE REDUCING VALVES, PUMP GOVERNORS, and TEMPERATURE REGULATORS Self-contained, spring loaded, internal pilot piston or diaphragm operated with stellited seat rings, hardened stainless steel trim, bronze, iron, or steel construc tion. All LESLIE Regulators feature: Control Pilot Type PD Accuracy of regulation comparable to instrument control Single-seated construction for positive dead-end shutoff . Quick valve action for sudden load changes Maximum resistance to corrosion and wear loaUcss Level Control for HeT9' Tanks, Evaporators, Heaters, Standpipes, etc. Maximum spring range--from mini mum to maximum controlled pres sure range without change of spring or diaphragm 1425 Diaphragm Control Valve . Class D-l Controls and Instruments!' Maxitrol Company 12200 Beech Road _ Detroit 28, Michigan LOW PRESSURE GAS REGULATORS Pacific Coast Distributor; PACIFIC SCIENTIFIC CO. ' San Francisco, Los Angeles, Seattle, Portland - Maxitrol gas regulators feature the patented "Straight-ThruFlow" design principle. This construction sharply reduces pressure loss commonly encountered in conventional type gas pressure regulators. The new feature permits greater flexibility in design of manifolds for domestic equipment, and frequently allows a reduction in pipe size of gas mani folds. Capacity charts at greater differential pressures for industrial use at inlet pressures up to 5 psi available on re quest. CAPACITY RATING (A. G. A. Listed) Model No. RV10 RV40 RV41 RV41 RV50 RV50 RV51 RV61 RV60 RV60 RV80 RV80 RV90 RV90 RV110 Rvno Pipe Size M H H K Ya H 1 1 IK IK m 2 2V4 2K 3 Cu Ft/ Hr at 0.3 Pressure Drop 0.6 Sp. Gr. Gas 15150 100 130 270 270 450 460 676 705 1,250 1.260 2,030 2,030 4,200 4,900 Btu/Hr Gases 800 Btu/ CuFt or More (Natural Gas) 11,000 111,000 74,000 96,000 200,000 200,000 333,000 340,400 500,200 521,700 925,000 932.400 1,502,000 1,502,000 3,108,000 3,626.000 Btu/Hr Gases Than 800 Btu/ Cu Ft (Mfd. Gas) Model No. 7,450 75,000 50,000 65,000 135,000 135,000 225,000 230,000 338,000 352,500 625,000 630,000 1,015,000 1,015,000 2.100,000 2,450,000 RV10 RV40 RV41 RV41 RV50 RV50 RV51 RV51 RV60 RV60 RV80 RV80 RV90 RV90 RVllO RVllO 1426 DIMENSIONS ABcD IH 2H 21M# 2HU 3 3 3*4 3H 4H AH 6 6 7K 7K 9 9 VHt 2H 2'M 2*Me 3>He 3>He 4K 4Ke 57At 5Ms 7 7 m 9H 12K 12K 2H 4K 32>*2 3*9*2 5K sht 6Ks 6Me 7K 796 8K 8K 9`Ke 9*M 14H 14K H lH **i2 *9*2 1H Hi 2M 2H, 2M 2Ms 2H 2H 2H 2H 3H 3H Ship ping Weight Each_ 3 02 Hf H* 94* if if lK* iK* 2H* 2H * 5* 5f SM* 9* 20 f 20* Controls and Instruments The Mercoid Corporation Main Office and Factory, 4201 Belmont Avenue, Chicago 41, Illinois New York Office, 205 East 42nd St. Philadelphia Office, 3137 N. Broad St. AUTOMATIC CONTROLS FOR HEATING, AIR CONDITIONING, REFRIGERATION AND VARIOUS INDUSTRIAL APPLICATIONS THE 100% MERCURY SWITCH EQUIPPED CONTROLS STEAM PRESSURE CONTROLS Type DA-31 Circuit opens on pressure rise. For application where pressures change slowly. Equipped with outside double adjustments for setting cut-in or cut-out points. Elec. Cap.--A-C or D-C 10 Amp, 115V, 5 Amp, 230V. i in. I.P.S. connection. Ranges 0-14 lbs, 0-30 in. vac., 10 in. vac.--12 lbs, 0-35 lbs, 0-60 lbs, 0-100 lbs, higher ranges available. Type DA-21 Circuit opens on pressure rise. For applications where pressures fluctuate rapidly. Similar to Type DA-31. Electrical Capacity same as DA-31 above. Ranges available to 2,500 lbs. HOT WATER TEMPERATURE CONTROLS Type 437 Circuit opens on temperature rise. Bimetal operated (back angle immersion well type) used as a high limit for hot water boilers. Equipped with outside double adjustment for setting cut-in or cut-out operating points. Electrical Capacity--A-C or D-C 10 Amp, 115V, 5 Amp, 230V. Connection 1 in. I.P.S. Ranges 80-240 F and 40-200 F. Type DA-36 (straight stem) Circuit opens on temperature rise. For immersion applications where bulb is directly installed into boiler water. Equipped with outside double adjustments. Electrical Capacity same as 437 above. Connection \ in. I.P.S. Immersion bulb 3 in. long. Ranges 100-200 F and 135-235 F. WARM AIR TEMPERATURE CONTROLS Type M-41 Limit Control. Equipped with outside adjustments for setting cut-in and cut-out operating points. Range 70 310 F. Type M-43 Fan or Blower Control has outside adjustments to gether with summer switch used for ventilating purposes dur ing summer. Range 50-300 F. Electrical Capacity all types A-C or D-C 115V, 10 Amp, 230V, 5 Amp. ROOM THERMOSTATS Type H, opens circuit on temperature rise (low voltage). Regulates heating equipment from True Room Temperature . without the aid of artificial stimulation. The Mercoid switch is unaffected by dust, dirt or lint. The cover has a jewel hard alumilite finish that will last a lifetime. Electrical Capacity Amp, at 24V, or less. Ranges 55-85 F and 65-95 F. Type R same as above except circuit closes on temperature OIL BURNER PRIMARY CONTROLS Type JMI (intermittent ignition) stack mounted safety igni tion control provides complete protection against flame or ignition failure--low line or power failure protection. Type JM (constant ignition) same as above except that no ignition switch is employed. Electrical Capacity A-C 10 Amp, 115V, 5 Amp, 230V. Write for Catalog No. 700ASHV. 1427 - Controls and Instruments MlNNEAPOLIS-HONEYWELL REGULATOR CO. 2644 Fourth Ave., S., Minneapolis'8, Minn. Cable Address: Minnreq, Minneapolis HONEYWELL CONTROLS for Heating, Ventilating, and Air Conditioning BROWN INSTRUMENTS for Indicating. Recording, and Controlling APPLIANCE CONTROLS for Gas, Water and Space Heaters MICRO SWITCHES for all applications VALVES for Industrial applications Fictories: Minneapolis, Minn., Philadelphia, Pa., Wabash, Ind., Fheepobt, III., Chicago, III.. Los Angeles, Calc?., Toronto, Canada >^ Branch Offices or Distributors are located in the following cities: Akbon, Ohio Davenport, Ia. Albany, N Y. Dayton, Ohio Albuquerque, N.M. Denver, Colo. Amarillo, Tex. Des Moines, Ia. Anchorage, Alaska Detroit, Mich. Atlanta, Ga. Augusta, Ga. Duluth, Minn. East Orange, N. J. Baltimore, Md. Eau Claire, Wis. Billings, Mont. Binghamton, N.Y. Birmingham, Ala. Boise, Idaho El Paso, Tex. Erie, Pa. Evansville, Ind. Fargo, N. Dak. Boston, Mass. Fort Wayne, Ind. Buffalo, N. Y. Fort Worth, Tex. Charleston, W. Va. (Aero only) Charlotte, C. Freeport, III. Chicago, 111. Fresno. Calif. Cincinnati, Ohio Grand Rapids, Cleveland, Ohio Columbus, Ohio Corpub Crristi, Tex. Dallas, Tex. Micb. Creensbobo, N. C. Greenville, S. C. Harrisburg, Pa. Hartford, Conn. Hastings, Neb. New Orleans, La. San Antonio, Houston, Tex. New Yobs, N. Y.' Tex. Indianapolis. Ind. Norfolk, Va. San Diego, Calif. Jacksonville, Fla. Oklahoma City, San Francisco, Joplin, Mo. Okla. Calif. Kansas City, Mo. Omaha, Neb. Seattle. Wash. Knoxville, Tenn. Peoria, III. Shreveport, La. Lansing, Mich. Philadelphia, Pa. Sioux City, Iowa Little Rock, Abk. Phoenix, Abiz. Sioux'Falls, S. D. Los Alamos, N.Mex. Pittsburgh, Pa. South Bend, Ind. Los AnoKles, Calif. Louisville, Ky. ^Portland, Me. Portland, Ore. Providence, R. I. Spokane, Wash. Springfield, III. Springfield, Lubbock, Tex. Richmond, Va. Mass. Madison, Wis. Roanoke, Va. Syracuse, N. Y. Memphis, Tenn. Menasha, Wis. Miami, Fla. Milwaukee, Wis. Minneapolis, Minn. Rochester, Minn. Rochester, N. Y. Sacramento, . Calif. ' Saginaw, Mich. Toledo, Ohio Tulsa, Okla. Washington, D.C. Wichita. Kans. Wilmington, Del. Mobile, Ala. Nashville, Tenn. St. Louis, Mo. Salt Lake City Worcester, Mass. Youngstown, New Haven, Conn. Utah Ohio . In Canada: Calgary, Edmonton, Halifax, Hamilton, London, Montreal, Ottawa, Quebec City, In Puerto Rico: Santurce San Juan In Cuba: In Mexico: Monterey, Mexico City, Guadalajara In Europe: London Brussels, Stockholm, Amsterdam, Zurich, Paris Toronto, Vancouver, Havana Windsor, Winnipeg ___________________________ _______________________________________________________________ AT YOUR SERVICE with automatic controls for every application. Minneapolis- Honeywell manufactures a complete line of electric, pneumatic and electronic con trols and regulators for every type of heating, ventilating, and air conditioning installation. Brown Instrument Division of Honeywell also manufactures a special ized line of indicating, recording, and controlling instruments. This means that you can rely on a single responsible manufacturer for all of your control needs. It elim inates the possibility of service difficulties and misunderstandings that often result from split responsibility when controls are purchased from more than one source. Each Honeywell branch office maintains a staff of experienced factory-trained engi neers who are qualified to give unbiased advice on control applications and to instaJi and service all types of control equipment. They are prepared to assist in the writ ing of specifications and to furnish control layouts and cost estimates without charge. ' ELECTRIC CONTROL Honeywell electric controls are noted, for variety, versatility, dependability and precision operation. The trade mare "Modutrol" is used to designate Honeywell electric .control systems designed for air conditioning or heating applications (other than domestic). It is your guarantee of Honejrwei quality. A wide variety of both modulating and two-position motors, controllers and valves provide a flexible selection o Modutrol Valve control equipment. . ELECTRONIC CONTROL Now, because of the many special features of Honeywell tronic Control, it is easy to achieve results which previous/ would have been extremely difficult or impossible. Electron controls are super-sensitive and accurate. They are simp in operation and very flexible in application. Honeyw electronic thermostats and humidity controls have no moy1` parts. A single one can be used to control heating, yenW*, ing and cooling. The control settings can be maintai constantly or may be reset automatically. An almost limited number of averaging and compensating controls Electronic Thermostat be used to obtain practically any desired result. 1428 . Minneapolis-Honeywell Regulator Co. Controls and Instruments PNEUMATIC CONTROL The "Gradutroi System" designation is applied to any com bination of Minneapolis-Honeywell automatic pneumatic con trols used to govern the operation of air conditioning or heat ing systems. This equipment may be used to obtain either two-position or modulating control in any desired sequence. Such features as the Gradutroi Relay, a Honeywell develop ment, which eliminates friction loss and allows accurate graduation of valves and damper motors, make the Gradutroi System a truly remarkable advance in pneumatic control. Pneumatic Radiator Valve COMBINATION SYSTEMS , The outstanding advantages of the Honeywell pneumatic Gradutroi System, the electric Modutrol System, and the Electronic Control System may be combined in a single in stallation. Thus, maximum flexibility, low-cost installation and dependable control results can be obtained. Honeywell can furnish controls for any particular type of system or for any combination of systems. This is your guarantee of fair and unprejudiced engineering advice as to the type of control best suited to your needs. ,* BROWN INDUSTRIAL INSTRUMENTS To obtain best results from modem heating and air condition ing equipment, it is necessary that the engineer in charge have a visual picture of actual conditions at all times. Brown in struments are designed to supply this information and to help operate the system at its highest efficiency. A complete line of industrial instruments is available for measuring, control ling, and recording temperature, humidity, flow, pressure, rpm, liquid level, pH, and fire safety. FREE HONEYWELL LITERATURE Listed are but a few of the many pieces of literature available, giving full infor mation on various Honeywell control devices and systems. Any inquiries you may have pertaining to Honeywell equip ment or some specific control problem will be given prompt, personal attention --whether you contact the main office in Minneapolis, or any of the Honeywell subsidiaries or branch offices located in principal cities throughout the United States, Canada, and other countries. Zone Control with Inside Thermostats Weatherstat Zone Control . Residential Zone Control Specifications Zone Control and Individual Room Con sol--For Homes Unit Heater Control . Control Systems for the Modern School Flan Your Hospital's Atmosphere Pneumatic Radiator Valves apring-Retum Valves Automatic Controls for the Marine In dustry Electronic Moduflow for Panel Heating Electronic Moduflow--For Homes Electronic Combustion Control Electronic Air Conditioning Control Electronic Humidity Control Apartment Heating Control Systems Aquatrol--Comm'I Hot Water Heating Control TnS?erS ant* Shutters Air Conditioning Controls Catalog WO Pneumatic Thermostat Brochure Brown Industrial Instruments Send your request for literature to Minneapolis-Honeywell, Minneapolis 8, Minnesota, or to your nearest branch office. 1429 fffi: I 'MA Controls and InstrumeWsm-I Controls and Instruments Milwaukee Gas Specialty Company 730 North Jackson St., Milwaukee 2, Wisconsin Sfjlf HR J1 -- BASO* THERMOELECTRIC SAFETY PILOTS s?- Straight through valves with one pilot tapping each side'll Cast, heat treated aluminum alloy bodies with replaceable^ I electromagnetic hood assemblies and reset assemblies. 100^? per cent shutoff safe lighting. Moeller Instrument Company 132nd St. and 89th Ave., Richmond Hill 18, New York Representatives in Principal Cities INSTRUMENTS FOR HEATING AND VENTILATING kY ..'7^ A 814 Model A814-1 A814-2 A814-3 A505-1 A506-1 Inlet Outlet y F.P.T. y F.P.T. y F.P.T. r f.p.t. 1y F.p.t. y f.p.t. y F.P.T. y F.P.T. 1# F.P.T. ly f.p.t. Pilot Tap ping y f.p.t. y f.p.t. y f.p.t. y f.p.t. y f.p.t. Capacity Btu/hr. 80,000 101,000 130.000 280.000 329,000 Thermo- p couple Type 1 > 88D 88D 88D 58D 8D i A 'f * ACTROL VALVE NO. MA5G1 Automatic main gas control valve. Maximum force exerted at beginning of stroke when valve is started from seat. Valve has built-in, replaceable, current limiting transformer for 24volt control circuits. MODEL MA5GI has straight through body tapped with ^ in. F.P.T. inlet and outlet. Valve can be mounted in a 360 deg circle around horizontal centerline of body. MA5G1 Electrical Rating: 8 Amps at Ito V, A-C 3 Amps at t$0 V, A-C 0.08 Amps at SSO V, D-C Switch type is wired in series with other controls. Opens circuit to main valve in case of pilot failure. Circuit closes automatically when pilot is relighted. MODEL No. 980 is a two-wire switch and No. 961 is a three-wire switch. 660 Switch . Basoid valves include in one cast brass body a solenoid valve for automatic main gas control and a 100 per cent shutoff safety pilot unit similar to Models ASM or A505. Available in many current types. Two pilot tappings. Series C Basoid in % in. size only. Model B4411 B4511 B4451-B1 B4451-B1 C4411 Inlet % F.P.T. 1'F.P.T. y f.p.t. r f.p.t. >/ fpt Outlet F.P.T. 1 F.P.T. y F.P.T. 1' F.P.T. */ F.P.T. Pilot Tap ping y F.P.T. y f.p.t. y f.p.t. y f.p.t. V* F.P.T. Current Type Capacity 115V, AC 115V, AC 20V, AC 20V, AC 115V. AC 159.000 189.000 159.000 189.000 94.000 Couple Lead Type 58 L) 58D 58D 58D 88D * Reg. U. S. Pat. OB. ANNULAIR PILOT BURNERS are available in a variety of tips and dual orifice inlet fittings for all kinds of fuel gas and pilot line connections. They are made in four types, "B" for low consumption appliances, "C" for medium consumption, and "D" and "F" for larger capacity appliances. Thermocouple leads of the 88D and 58D types are available in standard lengths from 12 in. to 72 in. and in special lengths to 240 in. Write for complete catalog SV-30O-3. 1430 MOELLER INDUSTRIAL THERMOM ETERS made in all forms, in scale ranges from minus 120 to plus 1125 F or its equivalent in centigrade. Available in 5 in., 7 in., 9 in. and 12 in. scale sizes. RECORDING THERMOMETERS, Mer cury Actuated, made in the round or rectangular cases. Charts 10 in. or 12 in., 1 hr, 12 hr, 24 hr or 7 day. Ranges from minus 40 to plus 1000 F or its equivalent in centigrade. DIAL INDICATING THERMOME TERS, Mercury Actuated, made in 4$ in., 6 in. and 8 in. sizes with flexible extension tubing. Scale ranges from rninus 40 to plus 1000 F or its equivalent in centigrade. Ml MOELLER BI-METAL THERMOME TERS are actuated by a powerful, spe cially processed bi-metal helix. Made with 5 in. diameter black crackle finish cast brass case, 4, in. diameter dial, scale ranges from minus 100 F to 750 F. THERMOMETER TESTWELLS, THER MOCOUPLE PROTECTING TUBES and WELLS, made up in all sizes and alloys. RECORDING PSYCHROMETERS, Mer cury Actuated. Round and Rectangu lar Case, 12 hr, 24 hr or 7 day charts, self contained or remote reading, with or without motor driven fan. ENGRAVED STEM and PORCELAIN and PAPER SCALE THERMOMETERS jnade in ranges from minus 150 to plus U25 F or its equivalent in centigrade. HYDROMETERS PLAIN FORM or COMBINED with THERMOMETER. Made in all scales. Standard and com mercial grades. Send for catalogs and literature on INDUSTRIAL# LABORATORY and RECORDING THERMOMETERS THERMOSTATS HYGROMETERS HYDROMETERS# PSYCHROMETERS and MARINE SPECIALTIES 1431 ;; I i: % f; !l-i|i. Main Office--Goshen, Indiana; In Canada--Penn Controls, Limited __ Offices and Representatives .' Albuquerque; Atlanta; Berkeley; Chicago; Cleveland; Dallas; Daytoh; Denver; Detroit; Los Angeles; Minneapolis; Milwaukee; Moline; Newton, Mass.; New York (North Bergen, N. J.); 13 E.Philadelphia; Pittsburgh; Rochester; Salt Lake City; St. Louis; Seattle; Export-- 40ra St., New York 16, N. Y. ' Wholesalers in All Principal Cities ' Automatic Controls for Heating, Refrigeration, Air Conditioning, Engines, Pumps, Air Compressors and Gas Appliances Thermostat* Oil Burner Stack Switches Warm Air Fan and Limit Control* HEATING CONTROLS A wide selection of controls is available for automatic heating service on steam, vapor, hot water, or warm air systems . . . gas, oil or coal-fired. Typical con trols in Penn's complete line are: Low and Line. Voltage Room Thermostats-- Stoker Timers -- Oil Burner Stack Switches--Magnetic and Motorized Gas Valves--Hot Water and Warm Air Tem perature Controls (including a complete line of Liquid Expansion Fan and Limit Controls)--Vapor and Steam Pressure Controls -- Relays and Relay-Trans formers--Humidist'ats--Day-Nite TernClocks--Pilot Burners and Pilot Gen erators -- Thermopilot Relays -- Low Pressure Gas Regulators -- Damper Motor Controls--and Solenoid Valves. For complete descriptions and specifica tions write for free catalogs. Relays Series t7l Dual Pressure Control COOLING CONTROLS A complete line of automatic commercial refrigeration controls ... in a wide choice of pressure and temperature mod els to fit every need. Series 270 single pole, standard duty or two pole, heavy duty controls feature direct reading, calibrated scales. Other controls in the refrigeration line include: Cooling Room Thermostats -- Humidistats -- Relays -- Solenoid Valves--Line Starters and Motor Contactors in Size 0, 1, and 1-- Water Regulating Valves in sizes up to 2\ in. N.P.T.--and Oil Protection Con trols for Pressure Lubricated Compres sors. Write for free catalogs which give complete descriptions and specifications. 1432 Water Regulators Series S75 Oil Protection Control Controls and Instruments <) DeRFEX " Milwaukee 7, Wis. corporation Perfex Controls Ltd., Toronto 1, Ont. BRANCHES IN: Belleville, N. J.; Milwaukee, Chicago, Philadelphia, Boston REPRESENTATIVES IN N. J.;--Belleville, Boston, Chicago, Cleveland, Columbus, Milwaukee, New York, Philadelphia, Portland, Oregon, San Francisco, University City, Mo. DISTRIBUTORS IN--Atlanta; Baltimore; Bangor, Me.; Burlington, N. C.; Cedar Rapids; Chi cago: Cincinnati; Cleveland; Denver; Des Moines; Detroit; Grand Rapids; Greensboro; Indian apolis; Kanbas City; Knoxville; Los Angeles; Nashville; New York; Omaha; Phoenix; Rich Siouxmond; Rochester, N. Y.; Salt Lake City; St. Louis; St. Paul; SiouxCity,Ia.; Falls; Wichita. INDUSTRIAL CONTROLS AND INSTRUMENTS Increased boiler efficiency, lower fuel costs, elimination of smoke, saving of operator's time--these are some of the bene fits of installing dependable Perfex combustion controls and instruments in the boiler room. Overfire draft control systems and modulating systems controlling fuel and air input for oil, gas, or stoker-fired boilers, draft gages, pressure gages, flue gas temperature indicators, combustion controls, draft con trols, program controls and actuators are included in this line of cost-cutting instruments. Flue Gas Temperature Indicator Pressure Gags Actuator Draft Control Draft Gay* AUTOMATIC HEATING CONTROLS Hot Water Controls Dependability and accuracy characterize the complete Perfex line of automatic controls for heating systems, unit heaters, electric heating, etc. The line includes thermostats (low and line voltage), limit and operating controls (for steam, hot water and warm air), primary controls (for gas, oil, stoker or hand firing), time switches, relays, and barometric draft regulators. Feature of Perfex controls is the ``Twin Con tact" Switch--which gives double action, positive contact, magnetic snap-action, immunity to vibration, doesn't require leveling and has no flexible leads to impede action or impair calibration. Lin* Voltage Thermostats Stoker Primary Controls 1433 OH Burner Primary Controls Magnetic Oas Vaises Controls and Instruments THE POWERS REGULATOR CO. Over 60 Years of Automatic Temperature and Humidity Control Factory and General Offices: Skokie, 111. Offices in Over SO Cities, U.S.A., Canada and Mexico, see yonr phone book. New York IV, N. Y. 231 E. 46th St. Los Angeles 26, CaL Chicago 13, 111. 3200 W. Temple St. 3819 N. Ashland Ave. Toronto. Ont 195 Spadina A ve. Mexico, D. P. Apartado 63 Bis. Some of the many controls employed in a Powers pneumatic control system for heating, ventilating, air conditioning and industrial processes are shown here. Controls for water heaters, fuel oil pre heaters and heat exchangers appear on third page. Powers Thermostats have true gradual action with no constant bleed of com pressed air. They give many years of dependable control with practically no maintenance. Various types for specific applications are available. Some are shown at left. A)Type D Single temperature range room thermostat has durable stamped brass cover and plastic insulating base. Because of its small size 5% H x 2J4 W x 2^6 in. deep, it fits into narrow vertical spaces. B)Type D Two-temperature range Day-Night thermostat. C)Type 190 Room Hygrostat for humidity con trol, duct type also available. D)Type D Summer-Winter remote bulb thermo stat for air conditioning units. E) Limitern thermostat for unit ventilators and ducts. F) Type K remote bulb thermo stat. G) Type K remote bulb Submaster thermostat/ H) Accritem Temperature Regulator has adjustable sensitivity and calibrated dial adjustment .with ranges 50-250F and 15O-350F. J) Static Pres sure Regulator for air ducts. Powers Series 100 Recording and Indi cating Controllers also control switches, gages, etc., are available in a variety of models; some are shown on control panels on next page. Powers Packless Diaphragm Control Valves Powers Packless Diaphragm Control Valves (K and L) are made in various types and sizes for convectors, unit ventilators, unit air conditioners or coils in ducts. With their durable construc tion, ample power and Duo-Seal pack less feature they eliminate normal packinggland friction and give better control. They eliminate steam or water leakage, loss of vacuum and packing maintenance. 1434 The Powers Regulator Co. Controls and Instruments UNIT VENTILATOR CONTROL Pow ers latest advancement the LIMITEM , Thermostat (E on previous page) is a precision instrument engineered to pro vide accurate low limit control of unit ventilator discharge temperatures ... a critical requirement for classroom com fort. It has sturdy construction, accu rate response, Powers famous NON WASTE double air-valve with adjustable sensitivity and graduated temperature dial for changing the control point. It is fully described in Bulletin S08. Modern Control Panel employing vari ous types of Powers pneumatic control ling, indicating and recording instru ments which regulate four complete year round air conditioning systems. Powers MASTROL Systems for control ling forced hot water heating, radiant panel heating, etc., are available in various combinations of Master and Sub Master controls. Control panel below shows MASTROL system using Powers Series 100 Recording Master Controller readjusting Sub-Master Indicating Con trollers. Powers modern line of diaphragm control valves, and dampers meet all heating and air conditioning requirements. Left: Powers FLOWRITE Valve--see other models on next page. Below: Powers 3 in. POWERSTROKE motor on damper. Above: G ill. POWERSTROKE motor on *arge louvre damper. 1435 The Powers Regulator Co. Controls and Instruments Controls and Instruments Rochester Manufacturing Co., Inc. 80 Rockwood St, Rochester 10, N. Y. OiftKMf ACCURACY ^3^ 274 Madison Are.. NEW YORK 16 9443 S. Ashland Are, CHICAGO 20.2949 Harriet Are.. S, MINNEAPOLIS - 1355 Market St, SAN FRANCISCO 3 6270 Strader St, PHILADELPHIA 24 . 4 Manor Rd,, East, TORONTO. ONTARIO. CAN ADA 31 Gordon Rd,, NEEDHAM 92. MASS. . 712 Marshal Bldg, CLEVE LAND 13 . 1254 Twenty-fourth St, N. W, WASHINGTON 7. D. C. Rochester Gauges--Dependable Accuracy Liquid level, pressure and temperature gauges in a wide range of types POWERS Temperature Control lor Water Heaters, Heat Exchangers, Fuel Oil Preheat ers, and many other uses. No. 11 Regulator below, is self-operating, especially adapted for hot water storage heaters. Available with 60F, ranges, various types of valve bodies and trim, also 3 way valves for water mixing. Accritem Regulator at right, is com pressed air or water operated, used to control Powers Flowrite or Metaflow valves. Is especially adapted for con trol of instantaneous water heaters, sub merged and indirect heaters, 2-Temp, domestic water heating systems--appli cations requiring accurate control and having frequent load changes and for large size valves. Has adjustable sensi tivity, calibrated dial temp, adjustment, ranges 50-250F and 15CK350F. Sensi tive bulb 12 in. long, ^ in. IPS connec tion. Thermostatic Water Mixing Valves-- complete line for individual shower baths, gang showers, hydrotherapy, hot water line control, and processes. Con tact nearest Powers office for bulletins. Packed three thermometers to a Kit, these thermometers permit accurate balancing of air temperature in any type of forced air heating. No further equipment needed. To be inserted in warm air duct, return air duct and near blower switch all at one time. Stainless steel with 2 in. easy to read dial 30-240 F and 9 in. stem with tapered bushing to fit snugly in awl or nail pierced hole. Sturdily and accurately made. LEAKPROOF, WEATHER PROOF OIL TANK GAUGES These highly dependable, easy-to-read fuel level gauges have been the standard of the industry for 25 years. They fea: ture a magnetic gauge action which makes them leak proof and pressure tight. The pointer is actuated by a per manent non-electric magnet in solid gauge head. Underwriters' listed. Mounts on top of tank at center or either end in pipe thread fitting---1$ in, or 2 in. for all domestic storage tanks, either in side or outside. PRESSURE AND VACUUM GAUGES Designed for indicating and testing. Pressure gauges, 0-200 lb-vacuum 0-30 in, 2 in. dial, i in. bottom connection. Kit 0500 One 200 lb pressure gauge, one 30 in. vacuum gauge. Kit 0501 As above plus one stack ther mometer---2 in. dial 100-1000 F. All gauges individually calibrated for accuracy. 1437 Controls and Instruments Simplex Manufacturing Company 198-206 North Main Street Fond du Lac, Wis. SIM-TROL Barometric Draft Controls--SIMPLEX Roof Vent Flashings Breechings and stacks must provide sufficient draft under adverse atmos pheric conditions. During normal and high barometric periods, cold months and windy days they generate excessive intensities with resulting inefficiency and fuel waste. ADVANTAGES SIM-TROLS automatically maintain a minimum draft required for good com bustion, fuel economy, increased heat transfer by reduction of gas velocity through the boiler, and minimize cold air infiltration and inrush causing sud den shrinkage of boiler parts. They eliminate local hot spots, floating and pulsating flame and sucking out of pilots. They improve feed water regulation, super-heater results, boiler life and boiler room ventilation. Type"A' SIM-TROLS aid materially in smoke abatement and boiler cleanliness by re duction of unburned combustibles and air dilution of stack gases. Lowered stack, temperatures prolong liner life and-reduce fire hazards. CONSTRUCTION . Properly sized SIM-TROLS adjust easily to any desired draft intensity. The races adjust laterally, the race assembly vertically, and the arm angle may be varied in relation to the plane of the gate. Gates of Type A and Type C SIM-TROLS rotate on cold rolled arbors and dust proof ball bearings. Curved tubular counterbalances contain metal balls which constantly change position to compensate for varying rotation angles of the gate, maintaining over-fire draft within 0.01 in. water, plus or minus. SIM-TROLS are protected by hard, heat resisting boiler room enamels. All coun terbalance members are outside, free from encrustment and corrosion by products of combustion. DESIGN FACTORS Sizing is important. The input opening should equal the stack area, plus 10 per cent for each 35 ft of stack height over 65 tt thereof. Preference should be given to control width, rather than height for ease of adjustment and smooth operation. Horizontal clearance from installation point approximates gate height plus 30 in Over-all height approximates gate height plus 37 in. Over-all width approximates gate width plus 8 in. Designs for limited space may be made if plans are submitted. Types A, C and F are individually designed to plant specifications presented, in cluding breeching and stack dimensions, clearances, fuel, method of firing and num ber of boilers. Detailed sketches are submitted for approval without obligation. GAS MODEL SIM-TROLS Types A, F and H are available to provide full back pressure relief and draft con trol. If specified, Types A and F are designed for use with coal, gas or oil by minor adjustment by the operator. 1438 Controls and Instruments Spence Engineering Company, Inc. 28 Grant Street, Walden, N. Y. Regulators for the accurate control of Pressure, Temperature, Differential, Back Pressure and Liquid Level; also Pump Gov ernors, Electrically Controlled Regulators, Desuperheaters and Strainers. - The SPENCE Type ED-W27 TwoStage Pressure Reducing Station is de signed to serve a heating system depend ably, at low cost and with utmost safety. The primary is a pilot operated, Type ED Pressure Regulator. SECO Metal trim affords guaranteed resistance to wiredrawing. The secondary is a direct operated, Type W27 Valve, simply con structed, yet engineered for long troublefree, heating duty. Note that the Diaphragm of the SPENCE Safety Pilot is connected to the low side. Should the secondary valve fail, this Pilot will assume control of the primary; thereby effecting a one-stage reduction from primary to final delivery pressure. A Spence Type E2T100 Temperature Regulator reduces the steam pressure in addition to accurately modulating the \ flow as required to control the temperature. No separate reducing valve is necessary. By adding a SPENCE Solenoid Pilot any SPENCE Regula tor may be cut on and off electrically. `i The Spence design provides a self-op erated, pilot controlled regulator en tirely packless in construction and guaranteed to shut tight. SECO Metal seats and discs will not be cut by the 'vire-drawing action of steam. Spence thermal elements are not injured by overheating. Pilot Type T100 is weight-loaded for heaters requiring not more than 10 psi pressure. Pilot Type T150 is spring-set for pressures up to 50 psi. Either may be used on a storage or instantaneous heater in combination with a main valve selected to suit the initial steam condi tions. 1439 Controls and Instruments Sterling, Inc. 3738 North Holton Street, Milwaukee 12, Wisconsin Healing and Temperature Control Products Distributed through leading Heating and Plumbing Wholesalers . Sales Representatives in Principal Cities Controls and Instruments jxuder InAirwmait Cxmijm/uzA ! Rochester 1, N. Y., U. S. A. - IN CANADA--'Taylor Inotrvmbkt Companies op Canada Ltd., Toronto NEW YORK CHICAGO BOSTON PHILADELPHIA BUFFALO LOS ANGELES ST. LOUI8 CINCINNATI PITTSBURGH SAN FRANCISCO TULSA CLEVELAND HOUSTON BALTIMORE Manufacturing Subsidiary in Great Britain, Short & Ma*cn, Ltd. London ATLANTA MINNEAPOLIS WILMINGTON SCHENECTADY SCOTIA Taylor Instruments for Indicating, Recording and Controlling Temperature, Pressure, Humidity, Flow and Liquid Level CONDENSATION and VACUUM PUMPS 4100 and 4200 Series (illustrated): neat, convenient unit with either steel or cast iron tank. Dual voltage capacitor type motor and carbon type rotary seal--for all jobs up to 15,000 sq ft EDR, 20 psi. 3500 Series: heavy duty units with pedes tal mounted steel tank for a wide range of jobs--2000 to 65,000 sq ft, up to 150 psi. 3700 Series: with heavy cast iron tank for installation underground or in wet locations. 2000 to 20,000 sq ft, 20 or 30 psi. Vacuum Pumps: Type V, 2500 and 5000 sq ft, 20 psi. Type S, 10,000 to 40,000 sq ft, 20 to 40 psi. Series 150-E TEMPERATURE CON TROL VALVES Self-powered, modulating control valves --applicable to any process involving heating and cooling by means of water, oil, steam or other fluids. Sturdy bellows --sealed valve with stainless steel trim and monel bellows. Armored sealed capil lary tube and thermostatic bulb. Ex tremely compact--MOUNTS and OPER ATES in ANY POSITION. Sizes: 'A in., % in., 1 in. Max. pressure: 125 psi. Direct or reverse acting. . Series 117-A: Dependable action for larger capacities. Sensitive thermostat bellows operates a pilot valve--steam supply pressure is used for smooth posi tive operation. Sizes: \]4 in., 1in., 2 in. Max. pressure: 125 psi. Direct acting only. 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. Com pact,' rugged, easy to service. Bellows thermostat vents air, float valve has plenty of capacity for large amounts of condensate. Sizes:% in., 1 in., lj^in., l)/ in., 2 in. Max. pressures: 15, 100 psi. THERM OTROLS Self-contained individual radiator tem perature controls for steam or hot water. Simple to install! Eliminate overheating, save fuel. Maintain even temperature fr comfort and health. Sizes: in., A in-, 1 in. Body styles: Angle, Straightway, Corner. THERMOSTATIC TRAPS: Keep radi ators clear of condensate without wast ing steam. Dependable bellows thermo stat, sturdy bronze bodies and covers, replaceable seats. Sizes: A in., % in., 1 re Max. pressures: 15, 65,100,125 psi. Body Also Strainers, Radiator Valves, Boiler styles: Angle, Straightway, Comer, Ver Return Traps. tical. . 1440 Dl F BE (A) Taylor Industrial Thermometers-- with BINOC* Tubing Includes many styles and scale ranges with bulbs for every application. These thermometers use the well known Taylor BINOC Tub ing--a designed and optically correct glass tubing which assures ease of read ing generally lacking in industrial ther-. mometers. BINOC tubing more than doubles the angle of vision within which readings can be made. Because of the patented triple-lens construction, its broad mercury column can be read easily and accurately with both eyes. Bore reflection is absent. (B) Taylor Blram*s Anemometer For measuring air velocities with fan revolu tions indicated on dial. Various models for a wide range of air speeds and regis tration limits. (C) Mason's Form Hygrometer. Pro vides temperature and humidity meas urements. Magnifying thermometer tubes are mercury-filled, approximate range 30 to 120F. Thermometer scales and siphon reservoir are mounted bn a mahogany finished wood panel, x (D) FULSCOPE* Recording Controller An air-operated controller that gives practically any character of process con * Trade Mark trol regardless of time lag in apparatus. Available for controlling temperature, pressure, humidity, rate of flow, liquid level. Where extreme load changes or badly balanced operating conditions exist, precision control can be main tained by the automatic reset feature. For applications where a record is not essential, Taylor supplies an Indicating FULSCOPE Controller. (B) Sling Psychrometer Two accurate etched-stem thermometers mounted on die-cast frame, with the bulb of one covered with a wick to be moistened. Whirling bulbs subject this hygrometer to complete air contact to produce ex treme accuracy of temperature and hu midity measurement. (F) Recording Hygrometer Records both wet and dry bulb temperatures on the same chart in different colored inks, making comparison very easy. ' Type shown has motor-driven fan for conditioned rooms or passages where circulation is poor. Furnished without fan for installations where circulation . across bulb is good. Taylor also offers a complete line of the famous Taylor Recording and Dial Ther* mometers; Ratio, Pneumatic Set, Self* Acting and Type MP" Controllers; Indi cating Hygrometers and many types of Humidiguides. 1441 Controls and Instruments White-Rod gers Electric Company NewYobk,N. Y. --' (Long Island City) Buffalo, N. Y. 1209 Cass Ave., St Louis 6, Mo. In Canada, White-Rodgers Limited, Toronto Chicago, III. Detroit, Mich. Distributors in Principal Cities - Cleveland, Ohio Philadelphia, Pa. (Havebtown) 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 Con- Refrigeration and Air-Condi- . trols . tioning Controls Hydraulic-Action temperature controls operate on the principle of expansion and contraction of a solid liquid charge against a diaphragm. This system, developed and perfected by White-Rodgers provides accuracy com parable to that of a fine thermometer . . . and other exclusive features guarantee ing unequaled performance. ADVANTAGES OF HYDRAULICACTION Hydraulic-Action controls provide maxi mum sensitivity--positive dial settings --full range accuracy--consistent differ ential--eliminates temperature drift-- simplified installation--extra sturdy switch mechanism--and other qualities that assure long satisfactory operation. Low voltage room thermostat. Ivory and chromefinish. Fan A Limit con trols in single case. Note the flexible ele ments. Also tn single units. PRIMARY CONTROLS In addition to Hydraulic-Action Con trols, White-Rodgers manufactures Oil Burner primary controls, Gas Valves (both diaphragm and solenoid types) and automatic safety pilots for gas installa tions. Line voltage thermo stat for unit heaters or atr conditioning installations. Diaphragm Gas .Valve. Available in variety of capacities. ' Silent in operation. Dual Hot Water Controls. Limit and Circulator, High and Low Limit combina tions. Also made in single controls. Remote bulb heavyduty thermostat, also available with selfcontained bulbs. Oil Burner primary control (stack switch). Intermittent or Con stant Ignition types. Contact your nearest White-Rodgers office for complete information. Catalog and engineering data furnished quickly. 1442 Heating Systems l^Sr Aldrich Company 121 E. Williams St., Wyoming, Illinois Boiler-Burner Units, Domestic and Commercial Oil Burners Aldrich Boiler-Burners are available in sizes for hot water heating, steam heat ing and hot water supply. Heavy duty double spiral hot water coils factory installed and tested in SC and WC models. Matched Aldrich Oil Burner with each unit, or choice of gas fired models. Welded steel fire box lined with re fractory of high deterioration resistance. Extra thick wool insulation minimizes heat loss. Easy access to fire box. ALDRICH GULF STREAM BOILERBURNER PACKAGE--Five sizes of com pact, economical units designed for the small home, fully erected, wired, equipped. From 440 to 1120 sq ft of water radiation. Quick heating load pick-up means fuel saving. Efficient and econom ical in operation. Tankless hot water coil optional. SERIES "B" BOILER BURNER SPECIFICATIONS Sise of Boiler Bantam 118 160 225 315 514 808 Rating Sq Ft Hot Water EDR.............................. Rating Sq Ft Hot Water Standing Radiation ... Rating Sq Ft Steam EDR............................... Rating Sq Ft Steam Standing Radiation . .. Rating Btu Per Ur (Max) Water Heater Delivery GPH ^ 100 Rise....... Storage Capacity Gal lons .......................... Firing Rate--GPH Maxi mum ... .... Firing Rate--GPH Mini mum ...................... Firing Rate--GPH Best Sq Ft of Heating Surface . Dia. Main Shell (Inside). Height of Main Shell.... 1-ha. of Fire Box (Inside) . Height of Fire Box......... Number ot l ubes........... Length of Tubes............. Output Hot Water WCGPM....................... Cod <> ioo Rise SC-C PM W0 750 1,000 1,500 2,100 3,300 5,000 440 500 650 1,000 1,400 2,200 3,333 425 500 630 935 1,275 2,025 3,000 285 333 420 620 850 1,350 2,000 100,000 118,000 160,000 225,000 315,000 514,000 808,000 93 125 190 280 450 610 850 20 28 38.5 72 99 120 170 1.00 1.25 1.65 2.75 3.65 5.7 9.00 .65 .75 CXI 17 16*$' 42*$' 12* 21* 16 15*$' .75 1.00 SAX1 21 19* 46*$' 14*4' 24' 16 15*$' 1.25 1.35 SAX2 27 21' 50*$' 16' 24' 20 19*4' 1.75 2.00 SAX3 44 24*4' 58 w 19* 26' 30 23*$' 2.4 2.5 SAX3 67 28' 66*$' 22*$' 26' 42 30*$' 3.7 4.5 BX 93 32* 66*$' 27' 26' 60 29*$' 6.00 7.5 BX 136 38' 70*$' 32*$' 26' 94 31*$' 3 1.75 2.00 2.66 5.25 6.50 7.25 3 2.00 2.75 3.67 6.75 8.00 10.00 GULF STREAM PACKAGE SPECIFICATIONS ________ Boiler No._____________ Net Rating SB 1 Water Sq Ft............ Net Rating SBI Btu Per Hour....... 21 Firing Rate GPH......................... Output Tankless Coil GPM IFHA).. Water Heater Delivery GPH--100" rise...................................................... Storage Capacity of Boiler--Gallons . Heating Surface Sq Ft....................... Number of Tubes................................ C-10 440 66,000 1.00 3 100 19 16 20 C-12 510 77,000 1.10 3 C-14 640 96.000 1.35 3 115 145 23 29 19 24 20 20 1443 C-20 880 132.000 2.00 4 C-25 1,120 168.000 2.50 4 195 255 31 39 32 41 32 32 Gulf Stream Packages i,. ' il ! n American - c$tat?dat'd American Radiator &. Standard Sanitary Corporation, Pittsburgh 30, Pa. American Radiator & Standard Sanitary Corp. Gfis end Healing Systems - Oil Burners. Water Heaters, Accessaries r 'i`i ii'if ?' 5! n: i 1. EMPIRE BOILER For all types of gas. Made in a com plete range of sizes for smaller homes and buildings with or without basement; also for domestic hot water supply. Ap proved by American Gas Association. A.G.A. Ratings: Steam-- 255 to 425 sq ft, Water--210 to 1,400 sq ft. 2. ARCOLINER WET BASE BOILER For oil. Compact boiler, with or without Arcoflame Burner, for small homes. Wet base construction ideal for homes with or without base ments. Ratings: Steam--260 to 520 sq ft, Water--485 to 940 sq ft, installed radiation. 3. OAKMONT BOILER For oil. Exclusively for oil firing. Also supplied as complete oil heating unit with Arcoflame Burner. Ratings: Steam--390 to 810 sq ft, Water--715 to 1440 sq ft, installed radiation. 4. STANDARD BOILER For all types of gas. Designed for larger homes and buildings. Approved by American Gas Association. A.G.A. Ratings: Steam--600 to 16,000sq ft, Water --960 to 25,600 sq ft. 5. EXBROOK BOILER For oil or stoker. Boiler in sizes adapted for larger homes and buildings. Available with Arcoflame Burner as oil heating unit. Ratings: Steam--775 to 1825 sq ft, Water--1380 to 3095 sq ft, installed radiation. 6. SEVERN BOILER For all fuels. Efficient boiler with advanced features for convenience and economy. Available with Arcoflame Burner as oil heating unit. Ratings: Steam-- 350 to 780 sq ft. Water--560 to 1390 sq ft, installed radiation. 7. REDFLASH BOILER For all fuels. Economical heat for any size or kind of building. Attractive jacket, fully insu lated. Ratings: Steam--770 to 9900 sq ft. Water--1230 to 15,840 sq ft, installed radiation. 8. WATER TUBE BOILERS For oil or stoker. For medium to large buildings. Efficient and economical. Ratings: Steam--930 to 4600 sq ft, Water--1640 to 7360 sq ft, installed radiation. 1444 1. RADIANTRIM PANELS Replace ordinary baseboards. Provide all the advantages of both convected and radiant heat. Sheet metal accessories also available for complete installation. 2. HEATRIM PANELS Popular-priced non-ferrous panels providing convected heat with forced circulation hot water sys tems only. Adaptable to mainless, or senes loop installations. 6-ft panels can be easily cut to shorter lengths. 3. SUNRAD RADIATORS Recessed or free-standing. Need no enclosure. Two sizes: 5 in. deep x 20 in. high and 71 in. x 23 in. Inlet grilles if desired. , 4. CONVECTORS With cast iron (Arco) or non-ferrous (New Multifin) heating elements. Styles and sizes for every need. Special designs for hospitals, institutions, etc. New Multifin Type K (shown) available in 63 packaged stock sizes. 5. STANFLAME CONVERSION BURNER Gas fired. Ver tical, upshot type burner for boiler, furnace, or winter air conditioner. Fits round or square combustion chamber. Runner pilot igniter. Burns all gases. Three models, with 10 A.G.A. inputs of 60,000 to 335,000 Btu. 6. BUDGET WATER HEATER--Approved by A.G.A. water automatically, stores it for instant use. enameled jacket, black trim. Thrifty and dependable. sizes--20,30 (shown) and 40 gal. Heats White Three 7. ARCO RADIATORS--Modern, highly efficient, slim tube radiators. Available in four widths--3, 4, 5 and 6 tubes-- and four heights--19, 22, 25 and 32 in. . 8. ARCOFLAME OIL BURNER--Listed by Underwriters1 Lab oratories. Complies with Commercial Standard CS-75. Special flange types for oil heating units. Pedestal types for conversion. Three models: Capacities up to 7 gal per hour. DETROIT HEATING CONTROLS AND] ACCESSORIES--A complete line of heating controls and accessories for all types of systems. 9. No. 861 Hurivent Vent Valve (for mains) 10. No. 300 Multiport Adjustable Air Valve 11. No. 999 Packless Radiator Valve 12. No. 116 Circulator Valve. 1445 Heating Systems Brown Products Company 97-12 Metropolitan Ave., Forest Hills, New York Brown Bayce-Heet is a "high-output" baseboard designed for residential and com mercial use. This smart looking new unit has a rating of 1100- Btu at 215 F. (4.6 sq ft EDR per lineal ft) made possible by the remarkable TILT-FIN design wherein two diagonally opposed fins are folded downward and the entire heating element (fins and tubes) is tilted to allow more efficient air circulation. For use on forced hot water or two pipe steam system. Heating element: 34 in. copper tubes expanded into rectangular beaded aluminum fins for greater strength and heat transfer area. BROWN AIR CONDITIONER The new Brown Air Conditioner brings summer cooling and dehumidification plus winter heating to even the most modest home. Designed with the plumb ing and heating contractor in mind, it is completely factory assembled and re quires only simple piping and electrical connections. Utilizing cold water for summer cooling and hot water for winter heating, this remarkable development discharges into the room cold or warm filter-cleaned air. Available sizes 1)4 tons, 1 ton and % ton. BROWN Heavy Duty BAYCE-HEET A revolutionary industrial fintube with many features that increase heating efficiency. Fins are beaded onto tube without tube expansion. This prevents fractures and provides a complete, bond between fin and tube for most .efficient heat transfer. Can be cut at any.ppint in the field. 2 in. IPS 32 fins/ft 4'K > x 434 1- fias 5*9 sq ft EDR per lineal ft. V/ in. IPS 32 fins per ft 434 in* x'4K |Dfins 6.25 sq ft EDR per lineal ft. 1)4 *n* IPS 32 fins per ft. 334 in. x 334 in4.35 sq ft EDR per lineal ft. Publication 800-1. . Brown Heet Convector Units in the distinctive heavy gage cabinet design can be used with forced circulating hot water, one or two pipe, steam vapor or vacuum systems. Heat regulation is by simple chain control damper. Tree standing or recessed style 20 in. or 24 in- high. 6 in. depth, 20 to 64 in. length, ratings from 17 to 68.6 sq ft EDR (4075 Btu/hr to 16,464 Btu/hr). )4 in. conper tube--expanded into aluminum ncs. Publication 600-1. 1446 Heating Systems Boilers, Gas and oa Bryan Steam Corporation Chili Pike, Peru, Indiana Hot Water and Steam Boilers designed exclusively for oil or gas firing. Products include domestic hot water or vapor steam boilers, commercial low pressure heat ing boilers for hot water or steam, and high pressure boilers up to 50 HP nest of tubes directly over the flame where heat is most intense. These tubes break up the path of heat travel, reduc ing "surface film" to a minimum. Of the many advantages of Bryan Boilers, none is more important than the use of Copper Tubes for the heating surface. All gas fired heating boilers A.G.A. approved. Bryan Copper Tube Boilers are engi neered expressly for oil or gas firing, where the flame is either on at full inten sity or entirely off. Such combustion characteristics call for a boiler that is able to capture heat units with utmost rapidity--and able to withstand sudden expansion and contraction. Average stack temperature of the Bryan is 412 degrees. BRYAN COPPER TUBES The Bryan starts with copper tubes. Copper has a coefficient of heat transfer approximately 6 times that of iron or steel. Heat applied to a Bryan tube is therefore transferred to the water inside 6 times as fast. The design of the Bryan tube is such that water circulates rapidly through all Parts of the boiler. There is a veritable Domestic Boiler* Commercial Healing Boiler* High Pressure Boiler* DOMESTIC BOILERS The Bryan Domestic Boiler is avail able in 7 sizes for hot water radiation. 70,000 Btu's to 560,000 Btu's. For steam radiation 5 sizes are avail able, 390 to 1560 sq ft of radiation. All models come complete with builtin combustion chamber and flange mounted oil burners. In gas fired mod els the burner is built in.- COMMERCIAL HEATING BOILERS Any of the domestic Bryans may be used for small offices or buildings; but they are supplemented with three additional larger capacity boilers. These boilers are rated 2600 to 5000 sq ft of steam ra diation or 4150 to 8000 sq ft of hot water radiation. They are used also for sup plying hot water or low pressure steam in industrial applications. . HIGH PRESSURE BOILERS Bryan High Pressure Boilers are made in 5-10-20-35- and 50 hp ratings. Every one carries the A.S.M.E. stamp. They are made for high efficiency on long, hard pulls but are exceptionally useful in operations requiring fast, safe steam on short notice. Hospitals, dry cleanmg plants, laundries, milk plants, tire repair shops and many others find them ideal for their operations. -yn M I Heating Systems Boilers, Radiators, Furnaces, Heating Accessories ' Grane Co. BOILERS, BASEBOARD PANELS, RADIATORS, FURNACES, VALVES, FITTINGS, PIPE, WATER AND STEAM SPECIALTIES, CONTROLS AND PLUMBING MATERIALS General Offices: 836 South Michigan Avenue, Chicago 5, Illinois Nationwide Service Through Branches, Wholesalers, Plumbing and Heating Contractors CRANE--A SINGLE SOURCE FOR EVERYTHING IN HOME HEATING Crane Co. Heating Systems Compac Radiators Type F (fabricated) Type RC (cast iron) Type R (cast iron) CRANE RADIANT BASEBOARD PANELS introduce an even distribution of radi ant warmth at floor level, leaving entire floor area free from obstruction. If base board area is limited, panels may be installed vertical or at ceiling level. Type RC provides radiant and converted heat. Type R provides radiant heat only. CRANE COMPAC RADIATORS--Slim slender lines give pleasing modern appear ance, require minimum space without sacrificing heat output. For free-standing or recessed installation, steam or hot water. Sizes up to 111 sq ft output, I=B=R rated. WATER SPECIALTIES--available to suit every installation--including water heaters, circulators and flow control valves. _ Crane)4 POWBoiler with "Kleen Heel" Oil Burner Crane 14 Boiler with Extended Jacket Crane 16 BoilerBurner Unit Crane SO Boiler with Oil Burner CRANE 14 POW--A truly complete cast-iron packaged, oil-fired water boiler pro vides everything necessary for a small home forced hot water heating system. Design improvements increase boiler efficiency. CRANE 14--These efficient, compact, low-cost boilers come in four sizes, up to 900 sq ft of water radiation. Available for gas, oil, stoker or hand firing. Oil model avail able with extended jacket as illustrated. CRANE 16--A completely packaged boiler-burner unit for steam or hot water systems. 1590 sq ft net I=B=R rating. Rugged cast iron construction. Patented Sustained Heat Principle assures fuel economy. . CRANE 30--Ideal medium-size cast iron boiler for larger homes, small commercial buildings. Net ratings: 3,000 sq ft for steam, 4,900 sq ft for hot water when auto matically fired. Easy-to-handle sections speed assembly. Crane 41 Boiler Crane-Line Steel Boiler Crane 2WG Gae Fired Boiler CRANE 41--New all-fuel boiler for institutions and other large buildings. Precision ground cast iron sections easy to assemble. Net ratings: 9,600 sq ft for hot water and 6,000 sq ft for steam when fired automatically. CRANE-LINE STEEL--A complete line of new, low-cost Crane-Line steel boilers. Available with and without accessory equipment, also with steel jacket. Maximum output 252,000 Btu for oil; 132,000 Btu for gas. CRANE 2WG--Only 33 inches high, this efficient gas boiler will heat the average fiveroom house at low cost with a minimum of attention. For hot water systems. VALVES--FITTINGS---The complete Crane line of valves and fittings offers all necessary piping items for any heating system. 1448 CRANE OIL BURNERS are newly engineered to provide automatic heating comfort at low fuel cost with a minimum of maintenance. GAS BURNERS feature "Spreader Flame" principle of construction and operation that eliminates losses due to incomplete combustion or excess air. CRANE ROOM AIR CONDITIONER is easily installed in any average-size window. ' Effectively cools, filters pollen, dust and dirt, removes humidity. Three models: H ton, % ton and 1 ton. Horizontal oil-fired furnace CRANE COUNTERFLOW FURNACE requires less than 4 sq ft of floor space with zero clearance on sides, rear, top. 85,000 Btu. Available for gas or oil firing. Maximum rating. . CRANE-LINE HORIZONTAL COUNTERFLOW FURNACE can be suspended in crawl space, from basement ceiling, or installed in an attic. Gas and oil models up to 85,000 Btu. CRANE-LINE BASEMENT OIL-FIRED FURNACE is a winter air-conditioning unit that heats, filters and provides forced circulation of heated air to all rooms. Available in bonnet ratings from 92,000 to 212,000 Btu. Base diffuser register A COMPLETE SERVICE. Crane can supply everything needed for any warm air "eating jobs--the correct furnace, piping, duct and fittings. 1449 Heating Systems v^.??" ^urnAam^^percUibj^ bOILEkS and RADIATORS Irvington-on-Hudson, N. Y. There's a Burnham for Every Purpose--Write for Descriptive Catalogs Heating Systems Baseboard Radiation Boiler Burner Units General Automatic Products Corporation 2300 Sinclair Lane Baltimore 13, Md. |JENEIE*L . Manufacturers of a Complete Line of Gas and Oil Heating Equipment FLOORLEVEL BASEBOARD RADIATION Hy-Power Model Base-Ray--Ratings-- 2.35 sq ft per lineal foot. Tappings-- % in. at top and bottom of both end sec tions. Sections are 7 in. high, 2 in. thick and in 12, 18 and 24 in. length. BurnhamRadiant Radiator--Two heights. 20 and 23 in. Ratings 2.25 sq ft per section and 3.40 sq ft per section. Burnham Slenderized Radiators--three to six tubes in all heights 19 in. to 32 in. At left: PACEMAKER Boiler for oil firing 270 to 710 sq ft for Steam and 490 to 1270 sq ft for Water. * Center: PB SERIES GAS BOILER--Power burner; 295 to 610 sq ft for Steam and 375 to 1,100 sq ft for Water. Available with year* round domestic hot water. Right: YELLO-JACKET Boiler (with extended Jacket) All Fuel Convertible 305 to 935 sq ft for Steam and 490 to 1600 sq ft for Water. No. 1, 2, 3 and 36 in. Series and 50 in. Welded Steel Boiler--Capacities froj Twin Series--All Fuel. 230 to 14,600 sq 2500 to 35,000 sq ft for Steam and 4809 ft for Steam; 370 to 23,360 sq ft for to 56,000 sq ft for Water. Furnishedfr Water. coal, oil or stoker firing. 1450 HOT WATER BASEBOARD RADIATION TWO TYPES FOR EASY INSTALLATION n. icai yciuucuu wanu an ucamu^ djotem, including new G/A round pipe dis tribution system. Available in complete packages. Adaptable to summer air conditioning systems. WARM AIR CONDITIONERS 85.000 Btu available in Highboy, Hori zontal, Counterflow and Lowboy models. Other models available from 115,000 to 200.000 Btu, Lowboy only. Includes burner, filter, blower, motor and con trols. DUAL DE-AIRATOR . Specifications Water Temp. 200 100 Q 180 Capacity (per lin. ft) STANDARD Hl-CAP. 500 Btu 750 Btu 445 Btu 676 Btu 390 Btu 606 Btu standard Element equiv. 3} sq ft per A complete unit for the elimination Hn. ft at 135 deg water temperature of air in hot water heating system; also difference acts as an expansion tank. Hi-Capacity Element equiv. 5 sq ft per lin. ft at 135 deg water temperature difference BOTH elements in complete PACKAGES "T" SERIES BOILER BURNERS Each package consists of enough mate rial to do the average installation for the amount of square footage required. The packages are sized to fit any installation. Carton No. 1 contains the fin type heat- *n element, assembled with front panel, "ack panel, etc., in 10 ft lengths, carton ^- 2 contains the front paneling, top moulding and fittings, and carton No. 3 Self-cleaning, rapid heating waterrtube boiler. Summer-winter hookup. Con tains lightweight, quick-heating, pre cast replaceable refractory. All sizes to 1,750 sq ft hot water and 1,090 sq ft steam. Heavy steel insulated jacket. contains the panel and moulding. Ele- CONVERSION BURNERS (Oil Fired) roents are interchangeable, without All sizes with capacity of 0.75 to 20 gpm. Bujustment to enclosure or other parts. G/A vibration free universal coupling. 1451 __________________ , - Heating.Systems The National Radiator Company AMODERN DESIGN HEATING EQUIPMENT Johnstown Pennsylvania Branch Offices: Baltimore, 2100 St. Paul Street; Boston, 620 Newberry Street; Buffalo, 17 Wells Street; Chicago, 400 West Madison Street; Cleveland, 2422 Prospect Avenue; Detroit, 5736 Twelfth Street; New York, 60 East 42nd Street; Philadelphia, 1218 Cherry Street; Pittsburgh, 125 First Avenue; Richmond, 308 West Cary Street; San Francisco, 681 Market Street; Washington, D. C., 4043 Georgia Avenue, N. W. I-B-R Symbol--National Cast Iron Boilers are conservatively and accurately rated by laboratory tests in accordance with the Testing and Rating Code of the Institute of Boiler and Radiator Manu facturers. _. SB1 Symbol--National Steel Boilers are rated in conformance with the Steel Boiler Institute Rating Code and will develop their catalogued ratings in accordance with the performance requirements of their code. A.G.A. Symbol--National gas heating products bear the A.G.A. Seal of Approval or are listed by the American Goa Association. ASME Symbol--All National boilers are designed, constructed and stamped in accordance with the requirements of the Boiler Construction Code of the American Society of Mechanical Engineers. '100" Series NATIONAL HEAT EXTRACTOR CAST IRON BOILERS Designed to fit the requirements of automatic heating, National Heat Ex tractors are provided with many features to insure high operating efficiency and maximum fuel economy. These include extended heating surface, multiple-flue section construction, effectively insu lated jacket and doors, and heat conserver baffles. Convertible from hand to automatic firing after installation and readily adaptable to any desired fuel or method of firing. Wide range of both storage and tankless domestic water heaters available. HEAT EXTRACTOR BOILERS Boiler Series 100 200 300 400 Net I=*B=R Ratings. Sq Ft Steam Water 170 to 470 350 to 880 700 to 2300 2500 to 6000 270 to 855 560 to 1560 1120 to 3835 4000 to 9600 Oil'Heating Unit NATIONAL OIL HEATING UNITS, cast iron or steel, provide complete "one package" equipment designed for maxi- "soo" Series mum efficiency and top performance with this fuel. Complete automatic controls, prefabricated' combustion chamber of proper proportions, quiet burner for rear firing and attractive all-enclosing jacket. OIL HEATING UNITS Type of Unit 100 Series Cast 200 Series Cast Residential Steel. Net Ratings, Sq Ft A.G.A. Approved Steam Water 230 to 470 400 to 880 275 to 700 430 to 855 730 to 1560 440 to 1120 1452 The National Radiator Co. Heating Systems Boilers, Radiators, Convectors, Baseboard, Unit Heaters Residential Steel Boiler NATIONAL STEEL BOILERS meet all the requirements of the SB I Testing and Rating Code and the ASME Boiler Construction Code. All are inspected and approved by a representative of a boiler insurance company. The 18 in. and 23 in. Series Residential Steel Boilers (for gas and oil) are designed for smaller homes. The 26 in., 29 in. and 39 in. Series RESIDENTIAL STEEL BOILERS for Hand and Auto matic Firing are designed for larger in stallations. The Commercial Series are adaptable to automatic or hand firing and are used for the largest installations. Commercial Steel Boiler RESIDENTIAL STEEL BOILERS COMMERCIAL STEEL BOILERS . Boiler Series IS" and 23' 26', 29* and 39' SB1 Net Ratings, Sq Ft Steam Water 275 to 700 440 to 1120 570 to 3000 910 to 4800 Boiler Type Automatically Fired................... Hand Fired........... SB1 Net Ratings, Sq Ft Steam Water 3000 to 35000 4800 to 56000 2500 to 29170 4000 to 46670 NATIONAL GAS BOILERS are modern, compact and designed exclusively for gas firing. Cast iron sections for long life and dependability. Tapered Hues, long zigzag fire travel and heavy insulation insure efficiency and economy. it, SS, U Series GAS BOILERS Boiler Series 22 33 44 66 Net Ratings, Sq Ft A.G.A. Approved Steam Water 110 to 390 355 to 980 445 to 1920 1770 to 12950 205 to 715 650 to 1725 810 to 3245 3010 to 20720 NATIONAL HEAT DISTRIBUTORS NATIONAL ART CONVECTOR--A non-ferrous convector, for flush and semior full-recessed installation. Aluminum fins bonded to copper tubing comprise tfie heating element. Enclosures are *n&de in a variety of types for residential NATIONAL AERO CONVECTOR-- Heating clement is made of cast iron with fins cast integral with tubes. Adaptable to any type of heating sys tem. Several types are available for residential or commercial installation. NATIONAL ART RADIATORS--Com pact, cast iron construction . . . blend 0r commercial installation. inconspicuously with most decorative schemes. 1453 The National Radiator Co.. THE NATIONAL PACKET A compact, all-in-one factory-assem bled automatic oil or gas fired home heat ing unit for small installations. An in tegral tankless heater provides domestic hot water. Model U is available with white enclosing cabinet. Model K is 36 in. high--kitchen counter height. At tractive white enamel cabinet. The Na tional Packet combined with Art Base board provides a modern, low-cost, easy to install hot water heating system . for homes, motels, diners and stores. National Packet, Model U SBI Net Rating Model U Model K 510 sq ft 440 sq ft National Packet, Model K NATIONAL ART BASEBOARD Type BF Type BR . Replaces customary wooden baseboard. Two types, BF (flush-to-wall) and BR (re cessed under plaster). Heating element consists of fins bonded to a copper tube. Designed for use with forced circulation hot water systems. Approved I-B-R Ratings. NATIONAL UNIT HEATERS National Gas-Fired . Unit Heater National Unit Heater, Vertical Delivery National Unit Heater, Horizontal Delivery Horizontal and vertical delivery. Variety of sizes available for use with hot water and steam. Gas-fired units can also be furnished with either cast iron or steel heat exchangers. 1454 Heating Systems . Sas'Sd oa Rite Engineering and Manufacturing Corp. 144 South Mission Road, Los Angeles 33, California . Phone ANgelus 9-7329 RITE HEATING and HOT WATER SUPPLY BOILERS GAS and OIL FIRED Water-tube type, designed for maximum efficiency and for every water heating pur pose. They are constructed and tested in accordance with the ASME steel boiler code, and we are authorized to apply the appropriate code symbol. Boilers are built with steel or copper 2 in. O.D. tubes. The boiler fire-box is cast at the factory. The boiler is insulated with rockwool and is covered with baked enameled steel jacketing. Boilers are shipped completely assembled with burner, operational and safety controls, and factory-installed wiring. RITE boilers are available with natural gas, L.P.G., mixed gas, Mfg. gas, light oil and gas-oil combination burners. IN P U T B.T.U. per hr. (Thous.) OUTPUT B.T.U. per hr. (Thoua.) G .P .H . 60F R ISE 'g .P.H. 100"F r is e WATER CAP GAL. lAPPROX. SHIPP. WT. LBS. 1 OUTSTANDING FEATURES COMPACTNESS E.D.R. i4 fcj O O BOILER-BURNER-CONTROLS UNIT --Completely packaged unit. RUGGEDNESS--Designed for 125 lb W.P. 15 150 120 800 240 140 7 520 20 200 160 1,066 320 190 8 600 25 250 200 1,333 400 240 9 650 *30 300 240 1,600 490 290 11 700 36 360 288 1,920 580 350 13 760 42 420 336 2,226 680 430 15 820 *48 480 384 2,560 780 470 18 850 *55 550 440 2,933 900 540 20 950 63 633 504 3,360 1,020 610 24 1050 *76 760 608 4,053 1,230 740 28 1300 *90 900 720 4,800 1,460 870 35 1600 105 1,050 840 5,600 1,700 1,020 43 1800 120 1,200 960 6,400 1,950 1,170 48 2000 *135 1,350 1,050 7,200 2,200 1,320 53 2200 150 1,500 1,200 8,000 2,430 1,460 58 2400 'l65 1,650 1,320 8,800 2,680 1,600 63 2600 *180 1,800 1,440 9,600 2,920 1,750 68 2800 200 2,000 1,600 10,666 3,250 1,950 73 3000 225 2.250 1,800 12,000 3,660 2,190 84 3100 2,500 2,000 13,333 4,060 2,420 91 3350 275 2,750 2,200 30l) 3,000 2,400 14,666 4,470 2,680 16,000 4,880 2,920 98 105 3600 3850 325 3,250 2,600 350 3,500 2.800 375 3,750 3,000 17,333 5,280 3,160 18.660 5,690 3,410 20,000 6,100 3,660 113 120 127 4100 4350 4600 4,000 3,200 21,333 6,500 3.900 134 4850 4,250 3,400 22,666 6,900 4,140 141 5100 4,500 3,600 475 4.750 3,800 24,000 7,310 4,380 25.333 7,700 4,610 148 155 5350 5600 5.000 4,000 26,666 8,120 4.860 163 5850 These boilers are A.G.A. approved. VERSATILITY--Space heating or hot water supply. SWIMMING POOL HEATING--Boilers equipped with copper tubes and nonferrous coating on a steel header. LOW DRAFT LOSS--Combustion prod ucts travel upwards. Minimum of stack required for gas-fired operation. COPPER TUBES--Are available in all RITE boilers. EASY TO CLEAN & MAINTAIN--Head plates remove easily. COMBUSTION CHAMBER--Fire-box high - temperature resisting refractory. Insulation thick layer of rockwool. QUIET OPERATION OIL BURNERS--Equipped with best available. CUSTOM BUILT--Special equipment or controls as specified. OPTIMUM WATER SURFACE ELECTRONIC PILOT SAFETY--Stand ard on 2,250,000 larger burners. 1455 Heating Systems * <^tek ^Cf&iFea DIVISION United States Radiator Corporation Detroit 31, Michigan Sales Offices in Principal Cities tat.O.S.ftrt.Ql Pacific Standard Firebox Boilers Pacific Scotch Marine Boilers Pacific Front Smoke Outlet Boilers PacificrS-pUt-Firebox Boilere COMMERCIAL BOILERS A Complete Line of Low-Pressure Steel Heating Boilers For Commercial Application All Pacific Commercial Boilers are built using the ASME Boiler Code Stand ards- as minimums, and rated in ac cordance with Steel Boiler Tnxlilute code. PACIFIC STANDARD FIREBOX BOILERS Pacific Standard Firebox Boilers for mechanical firing, stoker, oil or gas are built in capacities of 2680 to 56830 sq ft for steam and in corresponding capacities 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 capac ities of 2200 to 35000 sq ft for steam and in corresponding capacities for water. PACIFIC SCOTCH MARINE BOILERS Pacific Scotch Marine Boilers for oil or gas firing. Capacities of 5470 to 42500 sq ft SBI rating steam and in cor responding capacities for water. PACIFIC FRONT SMOKE OUTLET BOILERS Pacific Front Smoke Outlet Boilers for hand, stoker, oil or gas firing are built in capacities of 4000 to 42500 sq ft for steam and in corresponding capacities for water. PACIFIC SPLIT-FIREBOX BOILERS Low Water Line and High Firebox of Pacific Boilers are built in three sections --shell, firebox and base--and require minimum building opening. Where neces sary. Pacific fireboxes can be split (a3 illustrated) to allow the boiler to be taken into the building in four sections, through any ordinary door or window. No cutting, no welding is required in assembling any Pacific Boiler. 1456 Descriptive bulletins on Pacific Commercial Boilers will be mailed on request Heating Systems !,"?* DIVISION United States Radiator Corporation Detroit 31, Michigan Sales Offices hi Principal Cities HEMItl >1 t Pl Of. RESIDENTIAL BOILERS A Complete Line of. Residential Steel Boilers for Coal, Stoker, Oil or Gas Firing All Pacific Residential Boilers are built using the ASME Code Standards as minimums, and are rated in accordance with Steel Boiler Institute code. PACIFIC "PLATE FLUE'* BOILERS Pacific "Plate Flue" Boilers are designed for oil or gas firing and are built in 4 sizes. Capacities range from 400 to 900 sq ft steam and from 640 to 1440 sq ft water. They are available with either flush or extended jackets. PACIFIC ROUND STEEL BOILERS Pacific Round Steel Boilers are built of flange-quality steel and are available in 4 sizes. They are designed for steam or water and for either automatic oil or gas firing. Capacities of 320 to 400 sq ft steam and in capacities to 640 sq ft for water. Available with either flush or extended jackets. PACIFIC "O'* SERIES BOILERS Pacific "O" Series Boilers for residential application are designed for steam or water and for either automatic oil or gas firing. They are built in 7 sizes with capacities from 1100 to 3000 sq ft steam and in capacities to 4800 sq ft water. Available with flush jacket. PACIFIC RESIDENTIAL SQUARE BOILERS These Pacific Steel Boilers incorporate all the details of construction found in the larger type Pacific Boilers. Pacific Stoker-Fired Boilers are built in capac ities from 1140 to 2720 sq ft steam and in corresponding capacities for water. Pacific Direct Draft, Hand-Fired Boilers are built in capacities from 720 to 2100 scj ft steam and in corresponding capac ities for water. Descriptive bulletins on Pacific Residential Rollers will be mailed on request 1457 Pacific "Plate Flue" Boilers Pacific Residential Square BoRere Heating Systems Boilers, ca iTM United Shoes Radiator (Srporauoat *'* ** i ** *! HIATIHO General Office, Detroit 31, Mich. Branches and Sales Offices in Principal Cities Reg. U. S. Pet. Off. U. S. Boilers are manufactured for all fuels, for heating systems of all types, and for buildings of all sizes. U. S. Boilers equal or exceed all code require . ments. U. S. Gas Boilers are fully A.G.A. approved for all gases. U. S. Oil Boilers NOTE--The following boilers are available as Boiler-Burner units with U. S. Solar Flame Oil Burners: U. S.-12 and U. S.-21 (U. S. All Fuels Boilers), U. S.-46 (U. S. Oil Boilers). U. S. All Fuels Boilers U. S.-ll U. S.-ll I=B=R NET RATINGS U. S.13 u. s.-ts U. S.-t I=B=R NET RATINGS V. s.-ts Boiler Steam Sq Ft Water 1000 Btu hr U. S.-46 U. S.-2 U. S.-25 310 to 700 350 to 800 545 to 1985 86 to 188 97 to 225 148 to 502 Large Capacity All Fuels Boilers NET RATINGS Series Steam Sq Ft Water 1000 Btu hr "C" "40" "50" WN 2715 to 6110 2480 to 5800 5640 to 13,240 3885 to 14,630 651 to 1466 595 to 1392 j 1354 to 3178 ] 932 to 35114 Boilers U. S.-12 U. S.-21 U. S.-28 Steam Sq Ft 170 to 470 360 to 900 850 to 3030 Water 1000 Btu hr 41 to 128 86 to 239 204 to 742 U. S.Gas Boilers TJ. S. Thin Tube Radiators No. of Tubes 3 4 4 4 5 5 6 6 6 Height Inches Heating Surface Sq Ft per Sec tion 25 19 22 ' 25 22 25 19 25 32 1.6 1.6 1.8 2.0 2.1 2.4 2.3 3.0 3.7 v. s.-u u. s.-ie I=B=R NET RATINGS u. s.si U. S. Sunray Radiators Boiler U. S.-ll U. S.-16 U. S.-32 Steam Sq Ft Water Only 295 to 2090 2150 to 10,500 Water 1000 Btu hr Height Inches Depth Inches 27 to 108 82 to 527 540 to 2520 19'-2r-22^" 19'-21"-22V" 20* 5 6 5 1458 Heating Surface Sq Ft per Sec tion 1.8 2.3 2.25 _ Heating Systems Boilers, Cast Iron UnttedJStates Radiator (rporaiiox~ General Office, Detroit 31, Mich. Branches and Sales Offices in Principal Cities 0. S. Capitolalre Summer Air Condi tioners. Models available for economical installation with steam or forced hot water heating systems to provide yearround air conditioning in homes or commercial buildings. They have ample capacity combined with space-saving design and are equipped with complete automatic controls. U. S. Radiant Baseboard combines the best features of radiant and convection heating--radiant heat at floor level, plus convected heat to banish drafts. No structural changes needed. Simply replace baseboards. No dust, no dirt, inconspicuous, versatile, durable. For new or old buildings--residential or commercial. Ideal for remodeling old homes, and for basementless houses. D. S. Fin-Ray Radiation is ideal where heating require ments are heavy, space is at a premium, and low installa tion cost is a requirement. U. S. Fin-Ray is available in two styles: (1) steel tubing with steel fins (Types R and NR); and (2) copper tubing with aluminum fins (Type NFP). (Upper) Made in 1-J4 in. and 2 in. steel tube with steel fins. For baseboard, flat top enclosures, and expanded metal grille covers. (Lower) Made in 1 in. (nominal) cop per tube with aluminum fins. Baseboard enclosures and all accessories are furnished to fit any installation. U. S. Oil and Gas Burners for furnaces and boilers. Capacities: Oil Burners--0.6 gph to 15 gph. Gas Burners--75,000 to 300,000 (input rating, Btu per hr). U. S. Oil Burners (Upper) give de pendable service and low fuel consumption for homes, com mercial buildings, schools, churches, garages, etc. Commercialtype pressure atomizing oil burners in larger sizes also avail able. U. S. Gas Burners (Lower) are available in two models. Stainless steel flame deflector and support rod. Controls oper ate on low voltage current. S. Automatic Water Heaters, gas and electric. Gas--Capaci ties from 20 to 75 gals. Electric--capacities from 30 to 50. Also, table top, cabinet heaters available for both gas and elec tricity-capacity 30 gals. Well insulated with Fiberglas. Give dependable, efficient service at minimum cost. Durable finishes. U. S. Convectors are streamlined, sim U. S. Capitolaire Furnaces. Over 150 plified, standardized; for use on all two-pipe steam and hot-water systems. Heating elements are made of copper or firass tubes brazed to copper alloy headers. Can be connected at top or hpttom. Sturdy, durable cabinets pro- models to choose from--for oil, gas, and hand-fired coal or stoker firing. U. S. furnaces and winter air conditioners are real fuel savers. Streamlined cabinets are attractive in utility room, base ment, or recreation room. Engineered for long life, high efficiency and trouble- v'de easy assembly on the job. free operation. 1459 Spencer Heater Heating Systems Boaers, steel SPENCER H EATE R LYCOMING DIVISION SpORT PtH*4 Sales Representatives Allentown, Pa- Cincinnati, Ohio Harrisburg, Pa. Minneapolis, Minn. Portland, Ore. Atlanta, Ga. Cleveland, Ohio Houston, Texas Nashville, Tenn. Richmond, Va. Baltimore. Md. Columbus, Ohio Indianapolis, Ind. New Haven, Conn. Rockford, III. Binghamton, N. Y. Dallas, Texas Kansas Citt, Mo. New York, N. Y. San Antonio, Texas Birmingham, Ala. Detroit, Mich. Knoxville, Tenn. Philadelphia, Pa. Seattle, Wash. Boston, Mass. Grand Rapids, Mich. Memphis, Tbnn. Pittsburgh, Pa. Spokane, Wash. Chicago, III, Greensboro, N. C. Milwaukee, Wis. Pocatello,- Idaho Washington, D. C. STEEL AND CAST IRON HEATING BOILERS FOR EVERY BUILDING . . . FOR EVERY FUEL "LW" "A," "C," and "R" 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, and assures economical operation. . 2,600 TO 42,500 SQUARE FEET, STEAM Steel Commercial Heating Boilers--Ex? elusive peaked firebox design aids in making the "A" Boiler quick steaming and efficient. Space for either storage tank or instantaneous type service water coils. Larger sizes can be cut in half to move through narrow openings. "A" Series 910 to 5,000 NET SBI STEAM Steel Commercial and Residential Heat ing Boilers--For oil burner, stoker, or hand firing. With heavy-duty doors and frame precision-ground for airtight fit. Adaptable to front, rear, or side in stallation of oil burner or stoker. Avail able with domestic hot water coils and attractive insulated jacket. . 1460 "C" Series "LW" SERIES--3,500 to 42,500 SQUARE FEET, STEAM. New Divided Low- Waterline Commercial Boiler Flattened out to beat low headroom and excavation problems. Divided for easier entrance through narrow basement openings, yet 2 watertight sec tions require no welding. Easier to install because of specially designed smokebox. low stack designs possible because boilers designed to be installed with induced draft fans. Both instantaneous or tank type service waterheating coils; Quickly convertible from mechanical to hand-firing. SERIES--320 to 900 SQUARE FEET, STEAM, NET LOAD Steel Residential Heating Boilers--Excellent for small homes requiring economical heat and instantaneous hot water. Available with attractive beauty jacket. 340 TO 1,000 SQUARE FEET STEAM, Cast Iron All-Purpose Heating Boilers-- Especially suitable for homes where owner intends to convert to different type of fuel or firing at a later date. Has attractive jacket and special glass ob servation ports in fire and ashpit doors. Precision-ground, iron-to-iron sectional fit requires no caulking. "21" Series 290 TO 740 SQUARE FEET, STEAM Cast Iron Sectional Magazine Feed Boilers-- Highly efficient for burning economical buckwheat anthracite or pea size coke. No motors or moving parts. Fuel feedB automatically down unique Spencer slop ing grate with minimum attention. Per mits conversion to oil heat. 1461 I ' Heating Systems Boners, cast-iron 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. SMITH "CENTURY" GAS BOILER, A.G.A. approved, for steam or hot water heating. Input ratings from 138,000 to 745,500 Btu. Combines latest features of gas boiler design. Available with five sizes of built-in tank domestic hot water heaters, capacities to 168 gal, and eight sizes of tankless heaters, capacities to 8 gpm. Entire burner assembly mounted on wrought iron frame with casters for easy removal. "100" and "2000" OIL BOILERBURNER steam or water units for homes and small commercial installa tions. Furnished with line of tankless 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 modern 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; capaci^ ties 900 to 13,380 sq ft steam radiation. Independent header type construction. Tens of thousands are installed in . schools, hospitals, apartment houses, stores and other com mercial and public buildings. Models for hand and all types of automatic firing. SMITH HY-TEST BOILERS for hot water supply are furnished in several models, and many sizes for tank capaci ties to 20 000 gal. Constructed of the finest quality grey iron castings, these Hy-Test units are carefully tested at ex tremely high pressures before shipment. 42 and 60 SMITH BOILERS, may be used in batteries for < heating loads up to and over 100,000 sq ft steam radia tion. Many of these large units installed in industrial plants furnish steam for processing requirements as well as for heating and domestic hot water. STERLING FIN-TYPE RADIATORS for low-cost heat in public and commercial buildings, and baseboard convectors for homes, are distributed nationally by The H. B. SMITH COMPANY, Westfield, Mass. Complete catalog information describing Smith boilers is filed in current issues of Sweel's "Architectural" and Domestic Engineering Catalog Directory. 1462 3 32Heating Systems . S &F EL. UlEIL-fTIcLAlN COfllPANY General Sales Office Michigan City, Indiana Distributors in all principal cities SERIES 40 AND 44 HEAVY DUTY ALL FUEL BOILERS BOILERS FOR OIL AND OIL HEATING UNITS Square type sectional cast iron boiler for large commercial and industrial installations. Easily converted from one fuel to another. This boiler adapt able for horizontal rotary cup burner operation. A special front section, front plate and base panel are furnished so that the leading makes of rotary burners may be quickly installed. Com plete engineering information available on request. Load Range: Steam 2700 to 11,300 Water 4335 to 18,080 Sq Ft The OB, No. 57 and No. 77 Boilers are designed and built specifically for efficient oil firing. The Unit consists of boiler, burner, combustion chamber and controls. Flush or extended jackets are available on both the boiler for oil and oil heating unit. I=B=R Rated, ASME constructed. Load Range: Steam 285 to 1,130.Sq Ft Water 525 to 1,975 Sq Ft A Complete Line of Gas-Fired Boilers SNUG BASEBOARD PANELS Snug cast iron baseboard panels give a combination of radiant and convected heat--assure uniform temperature from floor to ceiling. A complete line of metal Jacketed cast iron gas boilers for natural, mixed, manufactured or lique fied petroleum gases. A.G.A. approved-- accessories for finishing is available. Height 7)4 in., Depth 2)4 in. Rating: 2.4 sq ft per lineal foot. ASME constructed. WEIL-McLAIN COMPANY ALSO MANU Load Range: Steam 395 to 12,380 Water 300 to 19,810 Sq Ft FACTURES A COMPLETE LINE OF MODERN CAST IRON RADIATORS, BOTH FREE STANDING AND RECESSED TYPE. 1463 / - Heating Systems Radutmi KRITZER RADIANT COILS, INC. "IF IT'S KRITZER, IT'S RIGHT SIR" - 2509A LAWRENCE AVENUE ' " CHICAGO 25, ILLINOIS Standard Baseboard Universal Baseboard Economy Baseboard Convector, Slotted Front KRITZER BASEBOARD HEATING KRITZER Baseboard includes five sepa rate types to meet every heating need. New design features make installation faster, easier, insure full operating effi ciency; and provide attractive finished appearance. Damper and positive ac tion control available. Full line of ac cessories includes joint covers, corners and end enclosures, with access panels if desired. Convector, Lowered Front Kritzer Fin-Pipe Coil Utility Cover . KRITZER FIN-PIPE COILS . These rugged, heavy-duty elements are ideal for industrial, commercial and in stitutional steam or hot water heating. Made with steel pipe or copper tube-- steel, copper or aluminum fins. Stand ard-fin spacings 24, 32 or 48 per ft; others by request. Complete line of covers and accessories available for the proper finishing touch to any installation. KRITZER RADIANT COILS . Simple in construction and easily in stalled, these coils provide a most efficient method of radiant panel heat ing. A combination of copper tube and aluminum fins they are concealed but not imbedded in structural materials. Enclosed in joist or stud spaces Kritzer Radiant Coils indirectly warm ceilings, floors or walls, wherever radiant panels are desired. 1464 Heating Systems Radiation Shaw-Perkins Manufacturing Company 201 E. Carson St. Pittsburgh 19, Pa.- Cutaxooy--Skaw Model A MANUFACTURERS OF Shaw Panel Radiators--Wall Hung or Free Standing . Perkins Industrial and Ceiling Radiators Shaw Baseboard Panel Radiators Corner Radiators Marine Radiators FEATURES------------- Long Life--Steam or water path 100 per cent non-ferrous. Strong box-type sec tional construction. Entirely factory as sembled. . Space Saving--Only three inches thick. High output. Safe--High pressure test. Rounded cor ners and grilles. Clean--Wide fin spacing. Smooth sur faces. Comfortable--Warm Panel Heating. Gentle air circulation. Shaw-Perkins Panel Radiators combine two of nature's basic elements--warm circulating air and mild radiant heat rays--in exact engineered proportions to pro duce activated, vitalized heat which permeates the entire room. Air is heated in each section of Shaw-Perkins Panel Radiators by the full length rigid steel plates which are positively bonded to the copper tubing containing the steam or hot water. The side walls of each section are also positively locked to the copper tubing and conduct heat directly to the radiant panel. This unique construc tion assures the exact engineered proportions of warm circulating air and mild radi ant heat rays which are necessary for health, well being and efficiency. Shaw sizes from 3.9 sq ft EDR to 110 sq ft (1 lb steam); Perkins sizes to 187 sq ft U lb steam). As high as 582 sq ft in one unit (150 lb steam). Shaw heights from 8 in. to 26 in. in front or top air outlet; Perkins heights from 14^6 in. to 32% in. Sup ply and return tappings on same or opposite ends. Shaw and Perkins radiators may be used on hot water systems, steam or vapor systems, high pressure steam systems and high temperature water systems. The many sizes and models of Shaw-Perkins Panel Radiators make it possible to select and to cover--with one specification--the correct Shaw-Perkins unit for any beating requirement--from one catalog--one set of heating tables--one source--one company. All sizes and types retain the same basic appearance which gives every Shaw-Perkins installation "the professional touch." Represented in all principal cities. Send for catalog "Modern Radiation." 1465 Heating Systems Boilers steel 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.. .Super heaters .. . Economizers .. . Air Heaters . . . Pulverized-Coal Equipment. . . Chain Grate Stokers. . .Oil, Gas, and Multifuel Burners. . .Seamless and Welded Tubing and Pipe. . .Refractories. . .Process Equipment. Heating Systems * Boilers, steei Cleaver-Brooks Company 498 E. Keefe Ave., Milwaukee 12, Wisconsin Cleaver-Brooks BOILERS--Steam or Hot Water, for Heating and Processing. 15 to 500 hp, 15 to 250 psi. Oil, Gas, and Combination Oil & Gas Fired Models. HP Approx, rated capac ity Lbs. Steam Per Hour 212F. COMPLETE SELF-CONTAINED STANDARD SIZES ~ 15 30 50 80 100 125 150 200 250 300 350 400 515 1050 1725 2700 3450 | 4300 5200 6900 8600 10500 12000 13800 CLEAVER-BROOKS STEAM BOILERS OPERATE AT A GUARANTEED 80 PER CENT EFFICIENCY WHEN FIRING WITH OIL Cleaver-Brooks boilers are guaranteed to operate at fuel-to-steam efficiency of not less than 80 per cent, at ratings from 30 to 100 per cent and at the designated working pressure. Economical operation is assured by establishing an efficient flame, ana utilizing forced draft to send the hot gases through four successive passes, thus ab sorbing maximum usable heat before-combustion gases leave the boiler. Boilers are fully automatic in operation ... meet ASME code requirements. Factory finished and tested under load conditions. B&W INTEGRAL-FURNACE BOILER, TYPE FM Shop-Assembled Steam Boiler This compact, self-contained unit com more practical and economical to have a bines all the advantages of "packaged" multiple-unit, Type FM installation steam plants with the service-proved rather than one or more large boilers re economy and dependability of larger quiring field erection and close operating B&W Integral-Furnace water-tube boilers that have been heavy favorites for years among power companies and all kinds of industrial plants. The Type FM unit is expressly designed for small and medium sized factories, institutions, and other buildings with problems of excessive fuel consumption and costly maintenance. Even for some supervision. The Type FM boiler is available in standardized sizes for steam require ments from 2900 to 28,000 lb of steam per hr at pressures to 235 psi. It is unusually sensitive to load changes; is fast-steam ing; features automatic push-button op eration with special safety provisions; is larger installations it has been found widely used with gas and/or oil firing- 1466 CLEAVER-BROOKS HELPS YOU SELECT THE EXACT STEAM BOILER YOU WANT TO MEET YOUR SPECIFIC NEEDS JOB RATED--Each Cleaver-Brooks steam boiler is job rated to meet the steam requirements of your plant. A competent sales engineer helps analyze your load de mands and takes into account these conditions: Pop valve settings Per cent of total feed water returned as condensate Tem perature of condensate Pressure of make-up water Type of fuel available Electric current characteristics Space and machinery arrangement. Suggested boiler room layouts Plant altitude above sea level Maximum steam require ments in pounds per hour or boiler horsepower Whether your steam load is con stant or fluctuating, and the degree of fluctuation The heating load requirements Standby requirements Steam pressure required at point of use Future growth 0r expansion of plant facilities Look for the "CLEAVER-BROOKS" listing in the Boiler Section of your classified Telephone Directory for name of nearest distributor. 1467 Heating Systems Boilers and Stokers Combustion Engineering, Inc. All Types of Fire Tube and Water Tube Boilers Mechanical Stokers Complete Steam Generating Units Pulverized Fuel Systems 200 Madison Avenue, New York 16, N. Y. Offices in all principal cities of the world More than 20t700 C-E Stokers purchased to date C-E SKELLY STOKER--A compact, . self-contained unit with integral forced- draft fan, designed to burn either bi tuminous coal or anthracite. Alternate fixed and moving grate bars assure lateral distribution of fuel. Automatic control is standard equipment. Approxi mate capacity range--20 to 300 rated boiler horsepower. C-E Shell)/ Stoker TYPE E STOKER--A single retort, un derfeed stoker designed to burn a variety of bituminous coals. Available with steam, mechanical or electro-hydraulic drive, it has a long established reputa tion for dependability. Approximate range--up to 600 boiler horsepower. Type E Stoker C-E SPREADER STOKER--A simple, rugged overfeed stoker designed to burn a wide variety of coals. Revolving spreader blades feed fuel into the furnace in criss-crossing streams which assure uniform distribution. Fines are burned in suspension and the coarser coal on a rate which may be of either continuous ischarge or dumping type. Rate of coal feed and air supply may be regulated over a wide range and are adaptable to automatic control. Applicable to boilers from about 100 boiler hp up. OTHER TYPES--In addition to the stokers described above, the C-E line comprises Traveling Grate and Chain Grate Stokers--including Coxe and Green designs--and the C-E Multiple Re tort Stoker. These stokers are generally applicable to medium sized and larger boilers and collectively are suitable for all kinds of solid fuel. The C-E line is complete and designed to meet every requirement. C-E Spreader Stoker--Dumping Grate Type C-E BOILERS--Comprise all fire tube and water tube types--see typical exam* pies on opposite page--including designs to suit all conditions of fuel, load and space. C-E Boilers range in capacity from 3,000 to 2,000,000 (or more) lb of steam per hour. Separate Catalogs describing each of these products are available.' B456-B 1468 Combustion Engineering, Inc. Heating Systems * |tokSisimd C-E PACKAGE BOILER, TYPE VP For medium-sized and smaller plants ... completely shop assembled .. . pressure to 250 psi. . . capacity to 30,000 lb per hr ... oil or gas firing. The VP is a completely packaged two drum vertical bent tube boiler with inte gral water-cooled furnace. Automatic controls provide protection from flame failure, high steam pressure and low water level; also adjust the air supply to the needs of fluctuating loads. Pressure fired, the unit requires no induced draft fan. Being self contained, it needs no special foundation and may be placed on a concrete slab or on a level floor. Only connections required are water, fuel, steam, electric and flue vent. C-E RE-CIRCULATION STEAM GENERATOR Compact . . . fully automatic . . . sizes up to 6000 lb per hr . . . operating pres sure to 300 psi. Gas and distillate fuel oil firing. This complete steam generating plant has wide application wherever steam is required for processing or heating ... in industry as well as in schools, hospitals and other institutions. Con trolled re-circulation assures minimum maintenance, high efficiency and maxi mum output per unit of space. Requiring a floor space only 5 ft by 7 ft and a height of but 8 ft, the unit needs no special foundation and is furnished complete with all auxiliaries. Push button con trolled, it is ideally suited for unat tended operation. Package Boiler, Type VP C-E Re-Circulation Steam Generator C-E VERTICAL-UNIT BOILER, TYPE VU-10 For medium-sized and smaller plants * pressure to 475 psi . . . capacity to 60,000 lb per hr, or more . . . suitable for any type of fuel. A standard unit, the VU-10 is especially designed for industrial load conditions and plants having limited number of operating personnel. It is of symmetrical design, and steam is released evenly across the full width of the unit. Gas flow 18 uniform, heat absorption is efficient and draft loss is low; it is essentially a quick steamer." The boiler is bottom supported with no outside supporting steel. Type VU-10 boilers are adaptable to stoker firing or may be fired with oil r gas. . 1469 C-E Vertical Unit Boiler, Type VU-10 Heating Systems Cyclotherm Division United States Radiator Corporation Sales and Executive Offices ~ - Oswego, New York Factory Distributors throughout the United States CYCLOTHERM STEAM AND HOT WATER GENERATORS Operate on Cyclonic Combustion prin ciple. Completely automatic with full safety controls. Oil, gas or interchange able gas and oil firing. Only four con nections required. The Cyclonic Combustion operating principle causes the fuel to be burned while spiraling at high velocity around the inside wall of the combustion chamber, forming virtually a tube of flame. This provides uniform and highly efficient heat transfer over the entire furnace wall without hot spots. Com plete utilization of heat transfer areas provides quick heat as well as greater than 80 per cent efficiency with the re duced maintenance of a two-pass design. 15 to 80 hp models are equipped with "on-off" control; 100 to 500 hp models have modulated control. 80 hp units with modulating controls furnished at customers request. Automatic combus tion safeguard, low water and other safety controls are included. Sizes from 18 to BOO hp ' Pressure Range Available in standard low pressure units or high pressures up to 200 psi. Hot water generators are also available in all sizes. Standard Burner Arrangements Fuel Cyclothenn Model No. Light Oil, 1 to 3 C-600 thru C 17,500 Heavy Oil, 5, 6 and Bunker C C-2800 thru C-17,500 Gas, mfd., mixed and natural C-600 thru C-17,500 Comb. It. oil and gas C-600 thru C-l-7,500 Comb. hy. oil and ' gas C-2800 thru C-17,500 Model No. C-600 CM000 CM 400 02100 C-2800 C-3500 C-4400 C-5200 C-7000 . C-8700 C-10500 C-l2000 C-13800 C-17500 Max. HP Rating 18 30 40 60 80 100 125 150 200 350 300 350 400 500 STANDARD RATINGS AND DIMENSIONS, Output BTU Per hr 600.000 1.005.000 1.340.000 2.010,000 2.680.000 3.350.000 4.187,500 5.025.000 6.700,000 8.375.000 10,050.000 11.725,000 13.400.000 16.750,000 Steam Units Steam Per Hr. (Pounds) 600 1,035 1.380 2,070 2.760 3.450 4.315 5.175 6.900 8.625 10,350 12,075 13,800 17.250 Equiva lent Di rect Ra diation (Sq Ft) 2,500 4.185 5.580 8,375 11,165 13.955 17.445 20,935 27,915 34.882 41,875 48.850 55.850 69.764 1470 Hot Water Units Equiva Gallons lent Di Per Hr rect Ra (100*Rise) diation . (Sq Ft) 743 1.240 1.655 2,480 3.305 4.135 5.170 6,205 8,270 10,337 12.405 14,475 16,540 20,674 4.005 6.700 8,930 13,400 17.865 22.330 27,915 33,500 44,665 55,782 66.900 78,115 89,330 111.564 Overall Dimension* (Inches) Length Height Width 71 804 1101 124 152 162 1734 1974 2244 2514 252 252 252 264 44 54 54 631 664 73| 84| 914 984 984 1024 1024 1024 1024 271 41 41 454 55 64 664 75 81 81 S8 88 88 88 Heating Systems iST8' The Dewey-Shepard Boiler Co. Sales Office: 1311 N. Capitol Avenue, Indianapolis, Ind. STEEL FIRE TUBE BOILERS & HEATERS GAS & OIL FIRED VERTICAL FIRE TUBE UNITS capacities 96,000 to 1,000,000 Btu ASMS CODE CONSTRUCTED All Dewey-Shepard boilers and water heaters (oil and gas fired) are built on the pat ented "Tube within a Tube" principle. All units are jacketed with fiber-glass insula tion ready for instant hook-up. Oil Burners Underwriters Approved. Gas Burners A.G.A. Listed. Boilers Automatically Welded. Built-in Coils Optional. Model' NET RATING Water, Sq Ft ' Steam, Sq Ft B. C D E F G H I J K L M 560 756 840 1120 1400 1540 1960 2120 2750 3000 4480 5960 350 470 520 700 875 965 1230 1330 1720 1895 2800 3730 Boiler ratings do not include allowance for Built-in.Cods. If piping and pick-up loss exceeds 20 percent of installed radiation, allow for such added loss. OIL and GAS BOILERS and WATER HEATERS Dewey-Shepard's patented "Tube within a Tube" principle gives you 80 per cent or more heat absorption, resulting in pre-heating the incoming cold water before it comes in contact with the metal surfaces to which radiant heat is being applied. There is one square foot of heating surface for every gallon of. water, transferring every possible unit of heat to the water, resulting in EFFICIENT, ECONOMICAL OPERATION . . . plus many other advantages for your customers, such as: LESS FUEL USED LOWER INSTALLATION COST NO LIME--NO SCALE* 20 PER CENT LESS HEAT LOSS THROUGH THE STACK*NO EXPANSION, CONTRACTION OR CONDENSATION* CLEANEST HEAT POSSIBLE* SUFFI CIENT HOT WATER AT ALL TIMES DEWEY-SHEPARD'S NEW OIL and GAS FIRED "COUNTER FLOW" BOILER Designed for use with Baseboard Radiation, Copper Convectors, and Radiant Panel with forced circulation and small pipe sizes. SPECIFICATIONS Output Net Btu 95,200 Net Rating 540 EDR Heating Surface 19 eq ft 1471 Size 31 in. x 19 in. x 19 in. ipprag Weight 300 Boiler 55 Burner Heating Systems Boa* Steel Dutton Boilers Division Hapman-Button Co. 639 Gibson Street, Kalamazoo, Michigan Four types, many sizes .. . From 5 hp up . . . Firing with gas, light or heavy oil, stoker coal or by hand .. . For processing, power, high and low pressure steam and hot water heating ... For Industrial Plants, Dairies, Laundry and Dry-Cleaning Plants, Chemical and Food Processing, Hotels, Schools, Institutions, etc. Heating Systems Boilers, steel Atlanta, Ga. Baltimore, Mo. Birmingham, Ala. Boise, Idaho Boston, Mass. Buenos Aibes, S. A. Charlotte, N. C. Chattanooga, Tenn. Chicago, III. Cincinnati, Ohio Cleveland, Ohio Cuyahoga Falls, Ohio Dai-las, Texas Denver, Colo. Detroit, Mich. Geneva, N. Y. Grand Rapids, Mich. Farrar & Trefts Incorporated ESTABLISHED 1863 20 Milbum Street, Buffalo 12, N. Y. FARRAR & TREFTS SALES OFFICES Greenville, S. C. Honolulu, Hawaii Houston, Texas Indianapolis, Ind. Ivtland, Pa. Knoxville, Tenn. Little Rock, Ark. Long Beach, Calxf. Los Angeles, Caup. . Louisville, Ky. Marion, N. C. Medford Lakes,'N. J. Media, Pa. M emphis, Tenn. Mexico City, Mex. Milwaukee, Wib. Minneapolis, Minn. Montevideo, Uruguay Nashville, Tenn. New Orleans, La. New York, N. Y. Nutley. N. J. Omaha, Nebr. Orchard Pare, N. Y. Philadelphia, Pa. Phoenix, Ariz. . Pittsburgh, Pa. Portland, Ore. Richmond, Va. Rochester, N. Y. St. Catherines, Ont. St. Louis, Mo. Salt Lake City, Utah San Antonio, Tex. San Francisco, Calif. Seattle, Wash. Syracuse, N. Y- Tamfa, Fla. Toledo, Ohio Tuiba, Okla. Washington, D. C Off-Center Firing With EconoTherm "Packaged" Models--Gas or OH or Com bination Gas-Oil. EconoTherm Models are automatic, selfcontained, "packaged" units with full safety controls. Of 3-pass fire-tube de sign, they feature a modified Scotch Internal Furnace located off-center. This firing creates rotary water circula tion, resulting in more uniform water temperature, fast steaming, steady water line at all times, and high quality dry steam. Higher water column above furnace adds extra safety, efficiency. Rotary combustion, large steam stor age space, and five or more square feet of heating surface per rated hp combine to deliver guaranteed 80 per cent ef ficiency with dryness rating of 99 plus 0/0 dry steam under proper operating conditions. Induced draft fan pulls gases through boiler for positive draft, fast-firing. Only a vent pipe is needed--no chimney or stack. Boiler shell is welded in one piece, X-ray inspected; complies with all ASME requirements. Every unit gets full running test. Certified ASME Data Report furnished. Multiple Convertible Firing - With The EconoMist "Packaged** Models. " EconoMist' Models are automatic, "packaged" boilers featuring multiple convertible firing. They can be.equipped for firing by hand, stoker, light oil, heavy oil, or gas, singly or in combina tions. Can also be fired with by-products such as wood chips, sugar cane., corn husks, waste gas, etc. EconoMist Models give you the de pendability and simplicity of operation of H.R.T. design, plus greater combus tion space, less heat loss. Installation, operation and maintenance costs are low. Welded boiler shell is X-ray in spected; complies with all ASME re quirements. Sizes from 15 to 105 hp are available as "packaged" units ready to connect or as basic units less refractory lining and accessories. Can be equipped with induced draft fan to eliminate need for stack or chimney. Conversion from one type of fuel to another is simple and inexpensive. Each unit is fully tested and certified ASME Data Report fur nished when shipped as a packaged unit. ECOHOTHERM--RATINGS AND CAPACITIES Equivalent- Hp Sq ft Water Heat. Surf. Lbs Steam per Hr 2G 25 30 40 50 75 80 112 125 151 201 300 356 400 700 773 1035 1726 2070 2450 2760 Eauivalent Hp Sq ft Water Heat. Surf. Lbs Steam per Hr 100 125 150 175 200 250 300 510 650 814 905 .1000 1252 1500 3754 4485 5617 6210 6900 8639 10,350 WKliJS illKbl,I UK UUIl IAV. 1 IUUK i/U 1 lull IVArAuO>li 1A11VA r\SXi ric TAILED SPECIFICATIONS AND DATA DESCRIBING THESE AND OTHER DUTTON BOILERS'- 1472 The Bison Compact Boiler Series 100 and 900 Firebox Return Tubular Boiler Series 600 and 600 The F&T Bison Compact Welded Heating Boiler is designed to have a large fur nace volume, the proper volume of water, the right amount of steam liberating surface, the correct volume for steam storage and a balanced circulation- The result is a remarkably steady water line--A Balanced Boiler. This boiler requires a minimum amount of floor space and is easy and inexpensive to install. It is reasonable as to cost and is economical in operation. Construction *s in accordance with ASME Code for 15 lb working pressure and boilers are de signed for hand or mechanical firing. Sizes from 2680 to 42,500 sq ft of steam ra diation. The Bisonette Compact Boiler has the same characteristics as the larger Bison Compact Boiler, and is designed for installation in large residences and small business establishments where the advantages inherent in a steel boiler are desired. . Firebox Return Tubular Heating Boilers are Quality Boilers constructed to meet the high standards of Heating Engineers and to give unfailing service under ail con ditions. Being economical to install and operate, they are highly favored by archi tects and engineers for heating Schools, Hospitals, etc. There are two types of Firebox Boilers, the Up-Draft Type and the Down-Draft type. Both types are made of welded or riveted construction for heating purposes at 15 lb working pressure and riveted, or, welded, x-rayed and stress relieved for power purposes at 100, 125, and 150 lb working pressure in accordance with ASME Code. Sizes from 5,470 to 42,500 sq ft of steam radiation are designed for hand or mechanical firing. _ Scotch Wet Arch Boilers are designed so that no refractory tile are required at the top of the rear combustion chamber. The steam space extends the entire length of the boiler and the furnace is entirely surrounded by water which permits imme diate maximum heat absorption. This special design results in a boiler that is ex tremely efficient to operate and is maintained at a minimum cost. The Scotch Wet Arch Boiler is a self-contained unit. It can be moved easily hnd can be installed on two saddles. No expensive foundation or pit is required. o external brickwork is needed. Because of its short length, low height and low water line, this compact boiler unit can be installed in small spaces where there is lack of headroom and where no other type will fit. It is designed for oil, gas or me chanical firing, in accordance with the ASME Code for 15 lb working pressure. bl?s range from 3,160 to 42,500 sq ft of steam radiation. Ratings of all these boilers conform to SBI. Write for Complete Catalog. 1473 Heating Systems BoUcrs, steel Reg. O. S. Pat Off. Fitzgibbons Boiler Company, Inc. 101 Park Avenue, New York 17, N. Y. Sales Branches in Principal Cities Member Manufactured at Oswego, N. Y. Steel Boilers since 1886 . Reg. U. S. Pat. Off. PRODUCTS--STEEL HEATING BOILERS for ail fuels and all heating systems. Capacities to meet requirements of any building. Built and rated according to ASME and SBI Codes and "Hartford" inspected. "D" TYPE STEEL BOJLER For mechanical 'firing with oil, gas or stoker in ratings from 3650 to 42,500 sq ft (steam), 5840 to 68,000sq ft (water), 876 to 10,200 Btu (1000's) EDR. 15 lbs Steam--30 lbs Water. For hand fired coal in ratings from 3000 to 35,000 sq ft (steam) 4800 to 56,000 sq ft (water), 720 to 8400 Btu (lOOO's) EDR. The steel boiler for heating apartments, office buildings, theatres, schools, hos pitals and other large commercial buildings. Provides year 'round service hot water, without the need of a separate storage tank,' with the famous Fitz gibbons TANKSAVER, a copper coil submerged in the boiler waifcr. A Full Wet Back--Low Pressure Heating Boiler for oil and gas firing in sizes from 5470 to 42,500 sq ft (steam) and 8750 to 68,000 sq ft (water), 1313 to 10,200 Btu (lOOO's) EDR. 15 lbs Steam --30 lbs Water. This compact, efficient Fitzgibbons boiler has the design advantage of complete water jacketing of all heat ing surfaces, including the rear furnace wall, thus eliminating usual rear dry-wall refractory lining and corresponding up keep and repair expense. 1474 .Fitzgibbons Boiler Company, Inc "80" SERIES STEEL BOILER For smaller commercial buildings and large residences for oil, gas or anthracite coal firing in seven sizes from 264 to 720 Btu (1000's)--SB I net. High in efficiency and fuel economy due to the generous firebox dimension and fast water circulation. Large tankless domestic hot water capacity year 'round, with Fitzgibbons TANKSAVER.. Heating Systems Boaers. steel R-Z-U JUNIOR STEEL BOILER Especially recommended for bituminous coal stoker firing, although equally excel lent for oil, gas and anthracite firing as well. In eleven sizes from 264 to 1200 Btu (lOOO's)--SBI net. Efficient firing with bituminous coal or other fuels is assured because of the ample tube area and di ameter, low draft loss and generally large combustion space. "400" SERIES STEEL BOILER The aristocrat of steel boilers for resi dences. Quick heating, low fuel con sumption. Abundant hot water, winter and summer, without the need of a stor age tank with the Fitzgibbons TANK- SAVER. In sizes from 400 to 900 sq ft (steam), 640 to 1440 (water). < No. 7701 STEEL BOILER A new steel boiler for hot water heating systems in small homes. High in heating efficiency and low in fuel consumption with a TANKSAVER copper coil for year 'round tankless domestic hot water. 510 sq ft water (77,000 Btu)--SBI Net Rating. No. 770 BOILER-BURNER UNIT * A completely pre-assembled and wired, oil fired unit for forced hot water heating systems in small homes. Combines the No. 7701 boiler, Fitzgibbons Oil Burner, TANKSAVER and all necessary con trols and specialties into a coordinated unit that provides abundant heat and tankless hot water at low cost. 510 sq ft water (77,000 Btu)--SBI Net Rating. 1475 Heating Systems Bones, sii The International Boiler Works Co. 500 Birch St., East Stroudsburg, Pa. Sales Offices In Principal Cities - "WATER TUBE BOILER DESIGN ASSURES. . . QUICK STEAMING . . . due to rapid and directed water circulation. MORE HEAT ABSORPTION ... due to extra long three pass gas travel, across the entire bank of water tubes. EASY CLEANING . . . free access to heating surfaces makes cleaning easy. Large Healing Boiler-Type C INTERNATIONAL WATER TUBE BOILERS are cutting fuel costs in thou sands of heating installations. Complete range of standard sizes Heating Boilers 400-70,000 sq ft steam, Power Boilers 10-600 bhp. Steel Boiler Institute ratings. Heating Boilers 15 lbs steam-30 lbs water. Power Boilers 125-150 psi. - All Boilers ASME standard For Oil, Gas, Stoker or hand fired Coal. Year round Domestic or Service hot water . . . from immersed copper coil, instantaneous or storage tank type. INTERNATIONAL--LA MONT* FORCED RECIRCULATION BOILERS Specifically designed for . . . Large Hi-Temperature Hot Water dis tribution systems. Hi-Temperature process systems em ploying Dowtherm, Aroclor, Socony Vacuum Heat Transfer Oil and other Thermal Liquids. Twin Section Healing Boiler-Type C (Also oxaHahle completely knocked* down-Type KD) Induced Draft Units for Heat or Power Write for complete catalog. * Licensed under LaMont patents. 1476 Power BoHer-Type CR HcQttlXQ iSySicTTlS Boilers, Steel Johnston Brothers, Inc. ESTABLISHED 1664 Ferrysburg, Michigan Member . u.s. "PACKAGED" STEAM BOILER UNIT FULLY AUTOMATIC HEAVY OIL AND/OR GAS WATER-BACK TYPE, FORCED DRAFT, THREE-PASS, TROUBLE-FREE, EFFICIENT. Catalog-Rating guaranteed and at least 25 per cent overloads readily ob tained. HIGH PRESSURE TYPE from 60 to 800 hp and pressures of 125, 150 and 200 lb psi. (250 lb available as a special) LOW PRESSURE TYPE for heating; 15 lb pressure, and EDR rating from 2190 sq ft to 42,500 sq ft steam. ASME Code construction. Specifi cation Forms in detail to exactly cover the requirements of any particular job will be furnished upon request and with out any obligation whatever. Ask for Bulletin 509. Standard Scotch Boiler Water-back Type, Natural Draft. Firebox Heating Boiler, Compact Type. Oil, Gas, Stoker or Hand Firing. ThreePass, 15 lb pressure, ASME Code. Capacities 2190 to 42,500 sq ft, SBI rat ing. Ask for Bulletin 1500. Also built for High Pressure (125 psi.) Ask for Bulletin 709. POWER PROCESS, HEATING. 25 to 300 hp and pressures 15 lb tp 200 lb psi. For mechanical firing with Coal, Gas or Oil. Overloads up to 200 per cent 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 4000 and 9000 and 9200. 1477 Heating Systems Orr & Sembower, Inc. Established 1885 Morgantown Road, Reading, Pa. PACKAGED automatic boilers PowerMaster boilers are modern, compact, self-contained, completely automatic unitB with an outstanding record for highly dependable and efficient performance. Standard sizes range from 15 hp to 500 hp for steam generation to 250 psi and for hot water to 30 psi. Powermasters are designed and built to ASME Boiler Code requirements, approved by Underwriters' Laboratories, Inc. and fully guaranteed by Orr <fe Sembower, Inc. All units are thoroughly factory tested under fire and sup plied with a complete test report. As delivered, Powermasters are fully equipped and completely wired for quick installation and operation. Thousands of .Power- masters are now serving industrial plants, dairies, hospitals, laundries, schools, institutions, and public buildings all over the U. S. and in many other countries. Low-Cost, Compact Installation--No foundation or costly breeching and stack are required. All necessary fittings supplied for readily completing fuel, water, elec tric, steam and vent connections. . Fuel Economy--Guaranteed 83 per cent minimum efficiency with No. 6 oil. Effi ciency actually increases at less than full load. Automatic control prevents fuel waste with fluctuating steam load. Clean, Quiet Operation--Complete, efficient combustion at all loads assures smoke less operation. Piped-in fuels and leak-tight construction aid cleanliness. * Completely Automatic Operation--Full complement of finest up-to-date operating and safety controls provides maximum operating dependability and protection with least possible attention from operator. Maintenance-Saving Accessibility--Water and fire sides completely accessible for easy cleaning and inspection without disturbing burner or accessories, Three-Pass Gas Travel--Successive parallel passes maintain most efficient flue gas velocity, provide maximum maintenance convenience, and eliminate complex front end baffling. ,. Staggered Tubes--Freedom from ineffectual boiler water eddies assures quicker heating, faster steaming, and high quality dry steam. Scrubbing action of rising water prevents corrosive gas deposits on tube surfaces. Forced Draft--Provides more accurate control of combustion air supply; permits use of smaller lower-cost fan and motor; requires less fan maintenance--no hot products of combustion pass through fan. . Modulating Combustion Control--Insures proper fuel-air mixture for most efficient firing at all loads. Instantly responds to load swings from 20 per cent to 100 per cent of firing capacity, assuring constant steam pressure and temperature. VORIFLOW Burners--Air-atomizing oil burner and pre-mix gas burner, designed ana built by O & S, provide complete, clean combustion over full firing range. Simple, sturdy construction and absence of moving parts minimize maintenance. Combina tion burner permits quick change from one fuel to another. 1478 Heating Systems -Boners, steel Kewanee-Ross Corporation Division of American Radiator & Standard Sanitary Corporation KEWANEE, ILLINOIS Branches in Principal Cities Consult local telephone book for telephone numbers. Appleton, Wisconsin Atlanta, Georgia Baltimore. Maryland Birmingham, Alabama Boston, Massachusetts Butte, Montana Chattanooga, Tennessee Chicago, Illinois Cincinnati, Ohio Cleveland, Ohio Columbus, Ohio Dallas, Texas . Denver, Colorado Des Moines, Iowa Detroit, Michigan El Paso, Texas Erie, Pennsylvania Grand Rapids, Michigan Gbbsn Bat, Wisconsin Greensboro, North Carolina Gbeenyillr, South Carolina Houston, Texas Indianapolis, Indiana Kansas City, Missouri Kewanee. Illinois Los Angeles, California Louisville, Kentucky . Cape Elizabeth,- Mainb- Memphib, Tennessee Milwaukee, Wisconsin Minneapolis, Minnesota . New Haven, Connecticut New Orleans, Louisiana New York, New York Oklahoma City, Oklahoma Omaha, Nebraska Philadelphia, Pennsylvania Pittsburgh, Pennsylvania Portland, Oreqon - Richmond, Virginia Roanoke, Virginia Saginaw, Michigan St. Louis, Missouri Salt Lake City, Utah ' San Antonio, Texas San Francisco, California Schenectady, New York Seattle, Washington Spokane, Washington Tampa, Florida Toledo, Ohio Tulsa, Oklahoma Washington, D. C. Wichita, Kansas Wilkes-Barre, Pennsylvania MEMBER KEWANEE PRESENTS A PRINCIPLE OF RATING TO AID ENGINEERS IN SIZING BOILERS KEWANEE Reserve plus RATING guarantees dependability--high efficiency-- low cost--long boiler life because it means operating at nominal capacity. Engineers everywhere know that operating a boiler continuously at maximum capacity lowers efficiency, increases operating and maintenance costs, shortens boiler life and is conducive to expensive breakdown. The proper sizing of a boiler for a specific job is all important. The Kewanee Reserve Plus Rating Plan presents a safe way of judging boilers for proper sizing. Here are the principles of the Kewanee Reserve Plus Plan : 1. Compare like examples when judging 50 per cent or more extra power for boilers. Know whether ratings are based pick-up and additional capacity. This on maximum capacity or nominal ca means the boiler can be operated at pacity. "cruising speed" for greater efficiency, 2. Nominal rated boilers with built-in low maintenance, dependability and reserve safely provide for fluctuating longer boiler life. loads -- emergencies expansion -- permit "cruising Bpeed" operation. 4. Kewanee Reserve Plus Rating is based on the approved code of the Steel Boiler 3. Kewanee Reserve Plus Rating certifies Institute. 1479 Kewanee-Ross Corp. i ' Heating Systems * BoUem, steel 00 a 11MV1Or. 52c52v-5 000 7 005 21wa a-on-*>oTol ofTt NS. |S` -- * 00>00 ^35^1 NCONfiNOtti Sl1"" "* 00 SSST?1?! 0 6r-. No 0M *V--Ov-< 0 g sg--M.022Wil S -*j> -* tr gj jc + is 00 -S-S Q g - s ..a /V 65! , OI ^* ft >3 8 g^x. ^ 52*23 O gxo Sg H . 5o3 fi & l,la *<Sj> e3g --^0*3< .--2fl bff2ll8o1^t^?o, 'C30.-ifst. Sc^S*.S9^9 2tCo^^*3Vu3X o.S>'O c l P*hr '3 5 .* ctf 3 w '5Cai .o-3ac| 'O <h WH S-S|g"l: 0 000 0 0 ooneat-ct wMc^f>- I^f. t tJ^ 3 2oMc SSST V? 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CO to 'll-- Sr 52 O = < . a t 2I -2 e o >1^ o -oicft.wSS-g-g>> "S= 05.S3 Cfi3 C a -O 2 c0: '- - .. *rs ft *a. ^2 5 ga ; ;x . -. ?^ tf: : jS O ft ft -PC w2"--S|o.of .2 2^S ocj ft> & r- -a Wh^,o /3 O r. -u ta^ <3*s 3 s MOO, >v t- 0,0 C3 B o ile r sl|?. 1 =5f T"?^ S J^l pJSccj .5 3 fimtoS 1480 ft> -in T H E R E ARE F IV E SIZES of the Scottie Jr., a ll capable of c a rry in g large overloads w ith o u t loss o f efficiency-- Underslung design means more headroom--steel rive te d -- comes ready to hook up--easy to clean-- rear com bustion cham ber has refractory insulation blocks installed at the factory. Kewanee-Ross Corp. Heating Systems Boaers, steel OO^ONff IvSSJ WJ =12522 "12522 s S-S.S.S 0000 II X>* SSC248O*0- oe5o50<PiM7V`--O^.r9j5 U 0000eop 308877270sa SNVSOt'OONtC- DQMOm 3 09 09Eh to 6>t SSSSSTE?? OS d r. I H M -888 | L M -888 00 55 SlS|l ff S 070020SS (EM SSSSSiAotJ. a",a.-' - 20001 00S01 0 4 --4^wDn.eMoneBwo E-J 001 001 57?5as S^SSsgsggg^000^ K-J rj 0770 2 2Sg Sga? ,,f e 5as SS| ,iJ.^A >o Sg 0 JoaooaNeP. x% 3 *260 1 1 0h-SOnINSs(oN^T m m 15 sC* t?oJl3 1481 T* Sgooogaooo XA 2 5ss "H|| a a ii 0MOQOOOt^O 53 32S "sggi ;i;li.MS x0~003 0 0w TT -lQ>OO t^D a S M CO NS0000Pt. ii "050s00l0020d.050A e B o ile r N u m b e r -- h ig h p r e s s u r e ... ........................1 -- lo w p re s s u re ................................ s W :gf Jce3Ss < 2o %& M ;:.*2 * ^ :m.&3 :: :: :' :' C/3 1=0 3 4a 0 3o ft J,_*S * *: : :- . ft K . J . g-c & : :.s?^ 03 5 3s o-ssl?f | ft :W.JS? A -- K.,o .2 1 12o r |^w *3 3g ig|s O 1 5333 5 5 W SJ|| 6 to CO ma ScO 'cSQo?asS Kewanee-Ross'Corp. 3.3 .a g V OV- sS-S-S 3 =><; 2 cSs? a|?a s|gg S'-SS* I 3 o5 ^f 9to ^3 3V<=J43 c3 acs Jc3tr** aa- 532 . a .. aj o 5 to ^ C t* . sS g C o ..bSa3C Ke--r5--5g aa-* 3*s - o -o - 3 e *> -^> 2"22?S'; 0 S a-S.S l-v-v 2 s& s - *3 o c . c ,, c 03 ^ 5>J.2o J 2 ato to : -*3 <5 o. g ^3 3 55 bo t- 3 ^ l i " 'S S g -m .m5>2~ 1" oS 3 - to *3 > *2 "cl 'S~ .Sr o m, S o <S JS t- to *3 Heating Systems Boners, steel I 5190 aoo~---*q .|Seoo5eSo ?i,>'S** ^ 0CXO0 sOnCDMns5Mog5g6--l?<--t"c*b 3 0e$oSo$oa2i'ciSo~'icoi a^Sr --1 Xt00-0J- 12322 1 . 7L85 1 gN0OMg^<Ofgl5^egloOTfNfOTojb; XCNO S3gg?T?T 3J SEgg'???'? ONOM cCO. OOpoC-Nf. t-- ONOON 09 t0X~0 sogsogog-^^o'rwvt?o 3 gggsSiTJ TT--1? -cr-o.s'ii 11112112 "a --PS 000 1I1I2||2 CD eo CCOD >D SCD K5S* g^S^ & >0 SJSsS^*' CO O BiajJH s e SSgg?*??? i3 S5g3?5f CC0OD gSggTTT? sMO S2OS2OSC4O:S00OSSC4_O'L*H-'n*'VJ)L DOO ooooo^-p-|tOsNgSs2-z- ^i OOO M3 OOOoOvOT^Pi-1^1- r- 20>0o0o0o 01--0-10-- D S2S2wJ>Nii 1 8178 S*D2--SD*S*O--TSCIONT2ao1 D Q3CO^O5OOC0C1tiOT0O- -1N0^r r. O 0S0--0<Sr0Sc4 t--0*L -2-b = = = S ss ?|5S3i Boiler Number...................................... I 5 ?s"^og" !` s8co -.lj "ttSWoc5of0f 1482 u .c2 . u 1 f : - .5 o*c s ::: cS- at?f 19fn*9 :. .-x.9:- 13 T 1 : ffl UA VA fill g " 5 111-* $ iSboo? .seSas *. S 2C TeS55 .X2! t. 5 cj 9 o 2 S A' 2 g 03 "C to .5 5 j u to f -too. O to +* M -*2 o ugD.f*ft*ol* ^Kto --d^ 1 1737 OOOWO 0 *&5c< >0 > <2o gSSsf 22 D SSSST SO A 4.c4 3*8 tog to to ^ 1 ,H g g g P"h .tToc3c l -* 1 -icD "O IfP p$ --tUo' MTct3oo - s s .llI..f*f EM I r^i f.'M\ .\r.lU? |i t:i wa 1483 Heating Systems Boners, sted THE TITUSVILLE IRON WORKS CO. TITUSVIUB, PENNSYLVANIA DIVISION OF STRUTHERS WELLS CORPORATION Designers and Manufacturers of Dependable coot BOILERS...since 1860 PACKAGE BOILERS Heating Systems Boilers, steel THE TITUSVILLE IRON WORKS CO. Titusville, Pennsylvania LOW PRESSURE HEATING BOILERS Type Designation Ticosteam The Titusville Type WTP Water Tube The Ticosteam Generator is a packaged Steam Generator is completely shop- steam power plant, completely equipped assembled, ready for operation as soon at the factory, tested and certified. Es as service connections are made. The sentially the unit is a three-pass, con Type W.TP features forced draft, pres stant furnace pressure, forced draft, fire surized furnace operation, and requires tube, horizontal boiler, with burners of no high stack or induced draft fan. It is special design using any desired type of adapted for firing with heavy oil, light gas, fuel oil, or combination of the two. oil, natural gas, coke oven gas or manu Built in sizes from 20 hp to 350 hp, this factured gas, and combinations of these unit provides outstanding economy in fuels. Capacities are from 7,500 to 30,000 operation, with thermal efficiencies of not lbs of steam per hour. ` less than 80 per cent. TYPE CM SPLIT FIREBOX BOILER Designed for replacement installations where entrance conditions are not suffi cient to accommodate standard boilers, the Titusville Type CM Split Firebox Boiler offers maximum utility and con venience. Separating into four basic sec tions (see cut), the Split Firebox CM Boiler can be taken easily through nar row doors and passageways impossible to negotiate by standard models, with out damage or alterations to building Wide range of sizes and capacities. 1484 Titusville Compact Steel Heating Boilers built in 19 sizes ranging from 129 square feet to 2500 square feet heating surface, and maximum steam working pressure 15 prig. Titusville Scotch Marine Heating Boilers built in 19 sizes ranging from 129 square feet to 2500 Bquare feet heating surface, and maximum steam working pressure 15 prig- HIGH PRESSURE FIRETUBE BOILERS 9 Titusville All-Welded Portable High Pressure Firebox Boilers built in 12 sizes ranging from 250 square feet to 2500 square feet heating surface, steam pres sure 100 psig, 125 psig and 150 psig. Type Designation Wee Scot to SO HP, SP a&o*e 60 OP Titusville Scotch Marine Power Boilers built in 13 sizes ranging from 9? square feet to 3000 square feet heating surface. Pressures 125 psig and 150 psig. WATER TUBE BOILERS Titusville Ticotherm Steam Generators in 13 standard sizes ranging from .'WO square feet to 5000 square feet heat% surface. Pressures 160 psig, 200 psig, 4)0 Psig and higher. Type Designation TDL Titusville Three Drum Low Head Water Tube Boilers built in numerous sizes ranging from 729 square feet to 6109 square feet heating surface. Pressures 160 psig, 200 psig, 250 psig and higher. Descriptive technical literature is available on request. 1485 Heating Systems Boners, sti Sid E. Parker Boiler Mfg. Go. 2035 East 37th Street Los Angeles 58. California Sales Representatives from Coast to Coast The Boiler of Advanced Design and Proven Performances Parker Industrial Steam Boilers, of bent water tube design with U-drum, are manufactured in a range of sizes from 1% hp through 100 hp. Built for either gas, oil, or combination gas and oil firing, with operating pressures from 5 to 150 psi. Completely packaged with burners installed and all controls mounted and electrically wired at the factory. Full steam pressure in less than 10 minutes. No brick work or special foundation required, minimizing in stallation costs. Economical, troublefree operation, easy, quick inspection of U-arum and water tubes. ASME . ' Model HWTUD No. 53 Gas Fired H HP 3 HP 5 HP 8 HP 12 HP 16 HP 22 HP 30 HP 40 HP 55 HP 37K' 40' nr 46' 4Q' 53' 59' 63" 70' 87* Height Oil Fired 50' 58' 63' 68" 78" 80' 91' 114' Height Gas & Oil Fired 17K' 20' 36" 43' 46' 52" 65' 72' a 00 116' Length Gas & Oil Fired 17^' 20"1 24" 26' .30" 34" 38" 49" 50' 55' Width Parker Industrial Hot Water Boilers Steel water tube design all welded con struction completely packaged, fully insulated, for either gas or oil firing. Ideal for all types of heating, radiant and convection, with extremely small lag or override. Widely used for supply ing hot water for restaurants, laundries, hotels and swimming pools. ASME ap proved. PARKER INDUSTRIAL HOT WATER BOILERS Boiler Model No. Gas Fired Height Oil Fired Height Gas & Oil Fired Length Gas & Oil Fired Width Output Btu/ hour EDR Sq ft T-150 T-300 T-450 T-750 T-1000 T-1500 T-2000 T-2500 T-3000 39" 39" 40" 40' 40" 40" 46" 46' 46* 51' 46' 46' 50" 54" 56" 59" 65" 67" 71' 79' 22' 28" 32' 40' 46" 49' 61" 7r 71' 85' 14' 14' 23" 23' 23" 25" 32" 38" 42" 54' 104M 144M 308M 384M 464M 691M 1000M 1382M 1536M12560-M 693 960 2005 2560 3093 4606 6666 9216 10240 ,17066. Write for literature and specifications 1486 Heating Systems Steam Generators Vapor Heating Corporation 80 East Jackson Blvd., Chicago 4, Illinois New York St. Paul Denver St. Louis % Atlanta Washington Philadelphia San Francisco Jacksonville Richmond Montreal Los Angeles VAPOR-CLARKSON STEAM GENERATORS Full Steam in 2 Minutes from a Cold Start Compared with conventional boilers, savings in time and labor, alone, can pay for a Vapor Steam Generator in less than a year--and it occupies about the space. ` Fully automatic; over 80 per cent efficient; clean; quiet . , . needs no sepa rate house; no expensive foundation or stack. Merely press a button to start. Steam delivery is at least 99 per cent quality, and only in the quantity needed. For every pressure-steam use-- Laundries . . . Dry Cleaners . . . Paper Box Making . . . Food and Milk Proc essing . . . Plastics Production . . . Steam Cleaning . . . Space Heating . . . Power Operation . . . Portable Service. type op UNIT ------ ------------------ 4611 4617 4626 4631 4636 _ 4741 HORSE POWER (212F.) 18 40 65 100 120 135 160 POUNDS STEAM PER HOUR (212F.) 620 1380 2240 3450 4140 4620 5520 . DIMENSIONS (Inches) Length 50 60 84 87 96 96 96 Width 41 48 48 60 60 60 60 48 64 71 73 78 78 77 WEIGHT (Dry) Pounds 800 1325 2240 3000 3900 4500 5900 MMm MOTOR . RATING Horsepower VAPUK NO. 4915 HOT WATER HEATER Here's a compact source of automatic hot water for many important uses. Output rating: 125,000 Btu per hour. Overall efficiency: over 80 per cent. Adjustable to turn "on" and "off" at pre-selected temperatures. Heated water is pumpehculated at approx. 10 gpm, and all phases of operation are guarded by full safety controls. Fuel: gas, Propane, oil. Furnished to operate with any specified alternating or direct current. Rectifiers furnished for combination ac-dc operation. As illustrated, 39 in. high; fits toto area 18 in. x 25 in.; weight, 250 lbs. Also available in hori zontal and suspended models. Typical Applications Ideal for both stationary and portable uses as a space heater; as a hot water supply; for maintaining proper temper ature of Diesel engines to eliminate warm-up, assure easy starting. A heavyduty unit. 1487 Heating Systems stokm Detroit Stoker Company General Motors Building - Detroit, Michigan Detroit LoStoker . (Underfeed type) Compact firing unit--single retort-- mechanically driven--plunger feed-side cleaning stoker. Sizes and capacity for all heating boilers, from 50 to 150 horse power rated capacity. Now available with Detroit Adjustable Feed--provides automatic control of coal and air. Effi cient and dependable operation assured. Detroit RotoStoker (Spreader type) Built with stationary, hand or power dumping grates or continuous cleaning grates. Wide range of sizes. Burns all bituminous coals without special prepa ration, but with high thermal efficiency. Responsive to fluctuating loads. Heating Systems stokers COMMERCIAL . INDUSTRIAL . RESIDENTIAL AIR-CONTROLLED BITUMINOUS STOKERS Detroit LoStoker--a great coal saver. Easily installed. Thousands in operation. Write for catalog. * Detroit UniStoker (Underfeed type) Plunger feed, side cleaning, compact unit type. For boilers of 125 to 250 hp rated capacity; Detroit Adjustable Feed keeps air supply in ratio to coal feed. May be motor or steam turbine driven, automatically controlled. Readily in stalled with existing boilers to provide automatic heat at low cost. Detroit RotoStoker (CC) is a new type with continuous ash discharge at the front. For steaming capacities approximately 5,000 to 75,000 lbs. Smoke-free operation at light loads. Detroit RotoGrate . (Large spreader type) For medium and large heating and power boilers up to 400,000 lbs steam per hourForward moving grates continuously and automatically discharge ash at the front. Combustion loss to ash usually less than two per cent. Detroit UniStoker with Adjustable Feed provides a wide range of coal feed control. Detroit RotoOrate Stoker burns all grades of Permits higher burning roles. Responds g changes in load. Burns wood and other rejuse rately or in conjunction with coal. 1488 ^ Patented automatic air control insures delivery of correct quantities of air to meet constantly changing fire-bed con ditions, eliminates need for banked fir ing methods and prevents back-smoking. If overload occurs, shear pin and auto- matic switch protect stoker against dam age. Strong, east iron hopper base with heavy gage rust-resisting steel hopper. Will-Burt hopper type stokers are avail able in 20 to 750 lbs per hr capacities. BIN FEED MODELS Like the hopper models, Will-Burt binfeed stokers offer all the advantages of automatic air control and the patented protective shear pin and switch. Pat ented flange and set screw locking device prevent coal screw from disengaging from drive shaft. Precision machined power unit. Capacities from 20 to 750 lbs per hr. CONTROL PANEL This prewired, pretested control panel mcludes magnetic starters, fused safety dutches, selector switches, hold-fire controls, shear pin alarms and time pitches. Controls are mounted and >ied on a sub-panel and completely enfjosed in a heavy gage steel cabinet. Cabinet provides adequate knock-outs ?nd convenient means for wall mountinS- At all times, stokers are protected oy individual limits, low water cut-offs od shear pin switches. "me ior 11 CC nvpy ui me wuii>un engineers 1489 Heating Systems Boa Ptedm McDonnell & Miller, Inc. Safety Devices for Steam and Hot Water Heating Boilers and Hot Water Tanks 3500 N. Spaulding Ave., Chicago 18, Illinois The McDonnell line consists of the following safety devices: (1) For Low Pressure Steam Boilers . . . Boiler water feeders, low water fuel cut-offs and combined feeders and cut-offs; (2) For Higher Pressure Steam Boilers . . . Pump controls, low water fuel cut-offs and low water alarms for pressures to 150 lbs, and receiver make-up water feeders; (3) For Hot Water Space Heat ing Boilers . . . ASME pressure relief valves, boiler water feeders, low water fuel cut-offs and combined feeders and cut-offs; (4) For Domestic Hot Water Tanks and Heaters . . . ASME pressure relief valves, temperature relief valves and combination T <fc P relief valves. McDonnell also manufactures liquid level controls, for humidifying pans and many other applications. 1 LOW PRESSURE STEAM BOILERS Service Recommendations Boiler Size. Maximum Steam Pressure _____ McDonnell Product to Use For Automatically! For Hand Fired Jobs ( Fired Jobs Boiler Water Feeders and Feeder Cut-Off Cdmbinations Up to 5000 sq ft Above 5000 sq ft Any size 25 lbs 35 lbs 75 lbs No. 47-2 No. 51-2 No. 53-2 No. 47 No. 51 No. 53 Low Water Fuel Cut-Offs (for Automatically Fired Jobs) Any size Any size 20 lbs 50 lbs No. 67 No. 63 McDONNELL Boiler Water Feeders and Feeder Cut-off Combinations McDonnell No. 47-S McDonnell No. 51-1 McDonnell No. 53-t McDonnell No. 47-2 Feeds water when necessary to maintain safe water level in boiler. If water level for any reason falls into emergency zone, cut-off switch cuts burner circuit until emergency has passed. Has "Quick-Hook-Up" for in stallation in gage glass tappings; "cool" feed valve; extra-deep sediment chamber; stainless steel valve and seat; ASME approved blow-off valve. Also available for hand fired jobs without No. 2 Switch, as No. 47 Feeder. McDonnell No. 51-2 is same as No. 47-2, except it has greater feeding capacity for larger boilers, and is installed with 1 in. equalizing pipes instead of "QuickHook-Up." Also available for hand fired boilers without No. 2 Switch, as No. 51 Feeder. For boilers operating at higher pres* sures, from 35 to 75 lbs,'use McDonnell No. 53-2 (or No. 53, without switch)- 1490 McPoTiTiell & Miller, Inc. Heating Systems McDonnell Low Water Cut-offs For automatically fired steam boilers of any size Maximum steam pressure, 20 lbs. ' No. 67 has McDonnell "Quick-Hook-Up" for installation in gage glass tappings; deep sediment chamber with large open ing blow-off valve; packless non-binding construction; adjust able terminal box; snap-action twin switches. One switch can sound low water alarm, or control McDonnell No. 101 Electric Water Feeder; second switch cuts burner current if water level drops into emergency zone. No. 61 has same mechanism as No. 67 but has larger body for installation with 1 in. equalizing pipes. 69 Series "Built-ins" meet same operating conditions, fit 2J^ in. tappings provided by many boiler manufacturers. Order by boiler make, model. . McDonnell No. 101 Electric Boiler Water Feeder For boilers up to 5000 sq ft capacity. For use with No. 67 Low Water Cut-off, No. 61 or "Built-ins" which are standard equipment on many modern heating boilers. Its use converts cut-off into feeder cut-off combina tion. 2 HIGHER PRESSURE STEAM BOILERS McDonnell Pump Control, Low Water Fuel Cut-off and Alarm Switch for steam boilers of any size; maximum steam pressure, 150 lbs. The McDonnell No. 150 Pump Control, Cut-off and Alarm switch for high pres sure and temperature. Has two switches; one controls electric feed pump or elec tric valve in line to steam pump; second stops burner on greater float drop and completes alarm circuit. Underwriters9 Laboratories approved. No. 150 has automatic reset; for manual reset order No. 150-M. No. 157 is same as No. 150, but has integral water column which simplifies installation, assures ideal reproduction of boiler water level in float chamber, and provides effective direct blow down. Available with varying water column sizes and tappings to suit practically all conditions. No. 157 has automatic reset; for manual reset order No. 157-M. (Tri-cocks and gage glass not included.) Operation of No. 150 or No. 157 Typical hook-up of the McDonnell No. 150 is shown at right. When water level drops, No. 150 starts pump and stops it when normal level is restored. In emer gency, cut-off switch stops burner; ter minals for low water alarm are also provided. This method holds boiler water level within the close limits necessary to at tain maximum steaming efficiency. Note McDonnell No. 27 make-up feeder on receiving tank. Drawings are avail able for all operating conditions, includ ing two or more boilers supplied by ne pump. 1491 McDonnell & Miller, Inc. Heating Systems Wafa _ _______ level Controls McDonnell & Miller, Inc. Heating Systems McDOWWELL No. 27 Make-up Water Feeder for -Receivers Teams up with McDonnell No. 150 or No. 157--assures an ade quate minimum supply of water in receiver at all times. Fea tures large feeding capacity, well-guided valve action, all brass construction of valve assembly. Models also available without float bowl for mounting right inside of receiver. Max imum receiver pressure, 35 lbs; maximum supply pressure 100 lbs. ' 3 HOT WATER SPACE HEATING BOILERS Service Recommendations Boiler Water Feeders and Feeder Cut-off Combinations Boiler Site (Btu/hr Output) Differential Pressure 10 lbs* Differential Pressure 20 lbs* Differential Pressure 30 lbs* Maximum Boiler Pressure 1,000,000 2,000,000 2,100,000 1.400.000 3,000,000 2.800.000 1,800,000 3.750.000 3.300.000 30 lbs 35 lbs 75 lbs * Differential Pressure equals water supply pressure boiler pressure. McDonnell Product to Use For Automati cally Fired Jobs For Hand Fired Jots No. 247-2 No. 51-2 No. 53-2 No. 247 No. 51 No. 53 Low Water Fuel Cut-off (only) (Jor Automatically Fired Jobs) McDonnell No. 63. For boilers of any size. Maximum Boiler Pressure, 50 lbs. ASME Safety Pressure Relief Valves Boiler Size (Btu/hr Output) Opening Pressure McDonnell Product to Use 303,000 743,400 1,025,100 1,488,000 1,928,400 30 lbs 30 lbs 30 lbs 30 lbs 30 lbs No. 230 % In. No. 230 1 In. No. 230 1}i In. No. 230-MI No. 230-M2 2,150,400 30 lbs No. 230-M3 McDONNELL Boiler Water Feeders and Feeder Cut-off Combinations Experience has shown that hot water heating boilers, just like steam boilers, can run into low water trouble--as a result of leakage in the system, prolonged discharge from pressure relief valves, or simple negligence. Best answer is a McDonnell feeder cut-off combination for automatically fired boilers, and a boiler water feeder for hand fired jobs. No. 247-2 is a modifi cation of the dependable 47-2, but without "Quick-Hook-Up." No. 51-2 and No. 53-2 are larger capacity and higher pressure feeder cut-off combinations. (No. 47-2, 51-2 and 53-2 are de scribed under "Low Pressure Steam Boilers.") No. 147-s McDONNELL No. 63 Low Water Fuel Cut-off Suitable for boiler pressures to 50 lbs, the No. 63 is ideal for cut-off service on hot water boilers. Has time-tested No. 2 low water cut-off switch, center pivoted bellows construction. Underwriter's approved. Can also be used on steam boilers. i S' 1 Manifold Type 830 Seriee McDONNELL 230 Series ASME Pressure Relief Valves for Hot Water Space Heating Boilers The 230 Series was developed to provide dependable protec tion against over pressure at a moderate price. Each valve in the series conforms to ASME Boiler Code in every respect, and has been certified, and Btu-rated by the National Board. All operating parts are of noncorrosive materials. Valve seat is brass, valve disc of silicone. Testing lever is independent of valve action, cannot interfere even if tied down. All connec tions are internal tappings. Six sizes are available, three individual valves and three manifold valves. These manifold valves offer two units, set to open at progressively higher pressures, on a common mani fold; they have the advantage of keeping discharge from larger boilers in step with the actual need, avoiding water waste when only a small discharge to take care of thermal expansion is required. 4 DOMESTIC HOT WATER TANKS AND HEATERS Service Recommendations Opening Pressure' 75 lbs 100 lbs 125 lbs 150 lbs ASME Safety Pressure Relief Valves Capacity Btu/hr McDonnell Product to Use 502,000 640,000 783,000 No. 230r75 No. 230-100 No. 230-125 925,000 No. 230-150 No. 30-75 McDONNELL 230 Series Pressure Relief Valves For Hot Water Tanks and Heaters Used to guard against dangerous over-pressure, the McDonnell 230 Series valves conform to the ASME Boiler Code and have been tested and Btu-rated by the National Board. Available with four standard opening pressures. Construction features non-corrosive materials for all operating parts, independent action test lever, internal tappings for connections. For larger hot water tanks, two and three valve assemblies are available, up to 125 lbs maximum pressure. McDONNELL No. 201 Temperature Relief Valve Safeguards hot water tanks and heaters against excessive temperature. A.G.A. listed for heat input to 1,200,000 Btu/hr. Vernatherm element provides positive operation, drip tight reseating. Extra connection for fixture flow simplifies pipe hook-up, improves operation. In regular or dip tube models. McDONNELL No. 202 Combination T & P Relief Valve Combines working mechanism of 230 Series and No. 201-- safeguards hot water tanks against both pressure and tem perature. Pressure side is steam rated at 644,000 Btu/hr. Tem perature side A.G.A. listed for heat input to 725,000 Btu/hr. In regular or dip tube models. 1493 Heating Systems Boner, Fi,,e bitoc Economy Flue Cleaner Company 819 11th Avenue South St. Cloud, Minnesota MANUFACTURERS OF AJAX BOILER FLUE BLOWERS Ajax Soot Blowers can be fitted to all types of fire tube boilers. They work equally well with high pressure steam or compressed air. 70 to 90 lb working pressure will service Ajax with either air or steam. action throughout the entire length of the boiler tube. One tube at a time is blown. All cleaning is done with the boiler doors closed and while the boiler is in full operation. No soot escapes and boiler AJAX is a locating device that bolts to the outside of the boiler doors. The flue pattern is drilled in the template after the unit has been bolted to the door. pressures do not lower during flue clean ing time. Blow HRT boilers against the draft. On two-pass boilers, short tubes are blown against the draft and long tubes with the draft. No special tools are required to make the installation. Allotf A three inch round hole through t.he one hour working time to install each door permits free operation of the uni unit. Type "CM Kewanee and boilers of versal joint and the ) inch pipe which similar "Two-Pass'y construction re slides through the sleeve of the universal quire four units because of the short joint. The far end of the pipe enters each distance between the flue doors and the flue end insuring a positive abrasive flue sheets. 1494 Heating Systems Burners * Gas and Oil Cleaver-Brooks Company HEV-E Burner Division 498 E. Keefe Ave., Milwaukee 12. Wisconsin Cleaver-Brooks HEV-E-BURNERS for commercial. Industrial and institutional use Use the most available and most eco nomical fuel in your area. Bum Oil, Gas or Combination Oil or Gas with equal efficiency. OIL--I lo 14 GPU Models ALt-S-4: AMIS-4; AMI-, S-, 4-H Heals with % 4 or 5 commercial oil HEV-E conversion burners can be in stalled as easily as domestic type burners to tire any acceptable boiler. Recom mended for buildings containing over 1500 sq ft of radiation--or if 45 tons of coal or more than 6000 gal of oil .are burned per year. Substantial fuel savings are gained by using low-cost S 4 or 5 commercial oil-- 20 to 30% less expensive than standard light oils. You save two ways: (1) Con sume less fuel, (2) pay less per gallon. Gas-fired units are similarly designed for utmost fuel economy. In combination models, fuel changeover can be accomplished in a few minutes by your operators. AH controls, regu lators and accessories are local and state code approved. GAS--720,000 to 8,700,000 Btu (MAX) Models AOt, S, 4,6, 7 Heats with nat ural , mixed or manufactured gas 9 models available. Burners equipped with automatic electric ignition. Motor starter delayed until oil at nozzle is heated. No expensive pilots needed. OIL--4 lo 60 GPH Models AM6-H, AM6-H, AM7-H 3 models available. Low-fire starting. Burner does not start at full capacity-- small flame builds up to required size. Uniform high efficiency assured by forced draft. SPECIFICATIONS--Rating* and Capacities 6 models available. Both gas and air are accurately regulated to give high CO* for dependable fire control. Top effi ciency under all atmospheric conditions. Combination Oil or Gas Models AMGi, S, 4 1 lo 14 GPH oil; 720,000 to t00,000 Btu gas. Modi Is AM G5, 6, 7 4 to 60 GPH oil; 8,600,000 to 8,700,000 Btu gas. Combination burners have same Btu output, burning gas or oil as regular HEV-E-OIL Burner. Same burner noz zle, gas head handles varying amounts of fuel. Safety electronic controls. 4CobbccM Im , Sq. lb EDS water No 1.1.1. 4 or S, HEV-E-BURNER--The Modern Burner Designed to Save You Money 1495 Heating Systems . oadGa, MAIN 'OFFICE AND flANT. 40 60A9DMAN H AC ITTA'iTTr * N C I S C 0 3 Eastern Agents ond Worehou** -- Coen Burner Soles Co., P.O. Box 7, Union City, New Jersey Omaha, Neb. Newton, la. Houston, Tex. AGENTS OUTLETS Denver, Colo. - Indianapolis, Ind. 111Chicago, . ' Los Angeles, Calif. . Boston, Mass. Salt Lake City, Utah Philadelphia, Pa. Atlanta, Ga. Seattle, "Wash. Montreal, Can. St. Louis, Mo. Portland, Ore. FUEL OIL PUMPING AND HEATING SET PAC-O-MATIC OIL AND GAS BURNER ' P. O. Box 331 Heating Systems Burners. Gas Gordon & Piatt Combustion Engineering Winfield, Kans. Coen Model 750CS4FPH Pac-o-matic Burner--Full Automatic lo develop 7,500 PPH steam. ' Coen Model Class AS Arrangement "V" 6 OM--Multifilm Heater Insulated and Metal Wrapped Coen Pump Sets for use with the heavier grades of fuel oil combine pump ing, straining, and heating fuel handling steps within one compact unit. These light weight units are available in two basic classes dependent upon indi vidual service requirements; i.e., stand by service or continuous service. Quality features standard for all classes include complete temperature and pressure con trol, choice of either duplex steam driven pump and/or motor driven rotary pump, and Coen's high capacity, low oil storage Multifilm tubular oil heater. Continuous classes for continuous servvice are equipped with Coen duplex suction and discharge strainers, and duplex heaters and pumps thus enabling complete dismantling and cleaning of either pump or heater. Three standard arrangements are available: horizontal side-by-side or tandem, and vertical. Write for Bulletins 14-50 and 80-27A. Coen Gas and/or Oil Pac-o-matic burners are designed for complete auto matic furnace operation with one single package unit. Engineered and manu factured for individual operation re quirements, Coen Pac-o-matic burner units are made for either water tube or fire tube boilers. Designed for each application, Coen burners allow fuel firing efficiencies not previously possible over so wide a firing range. Pac-o-matics are capable of oper ating at 10 per cent to 11 per cent COt with gas firing, and 13 per cent to 14 per cent COa with No. 6 oil firing. Automatic slow opening damper and register louver control allow this nigh efficiency to cover 80 per cent of working turn-down ranges of 8-10 to 1. . Pac-o-matic burners are available m sizes from 1,000 to 20,000 lbs of steam per hour (30 to 900 hp). All are complete wit-n approved flame failure, limit devices automatic combustion control. Write for Bulletin Pi52. COEN CIRCULAR REGISTER TYPE BURNERS . All standard Coen burners make use of the circular air control register mixes atomized oil and all necessary combustion air immediately as it e.nter^tj.e furnace through a circular firing throat. It is recommended that the selection 01 complete burner consisting of the air control register, oil atomizer and/or gas burn best suited for the individual application, be made only with the recommends, of Coen Company engineers. Write for Bulletin 48. 1496 Gordon & Piatt Type "HP" Gas Burner Type "H" and "HP" Gas Burners are horizontal type burners, consisting of mul tiple cast iron venturies with flame retention heads, housed in a steel casing, and provided with balanced air louvres, and plain pilots. They may be used with natural, manufactured and liquefied petroleum gases. As this burner assembly consists of a group of heads, it can be supplied in shapes and sizes to fit any job. However, stand ard sizes for natural gas, ranging from 275,000 to 6,600,000 Btu per hour at 4 in. W.C. gas pressure, are cataloged. Type "H" and "HP" Burners are designed for use in scotch marine boilers under conditions of natural or induced draft and low gas pressure, or other boilers where a horizontal type of firing is preferred. Type "HP" is fitted with packaged control assemblies for simplified installation. Gordon & Piatt also manufacture: . Truliradiant vertical gas burners, for natural gas, which consist of multiple castmon venturies and port caps with a special refractory cap, manifolded into sizes. lo fit most fireboxes. It is an atmospheric type burner using natural or induced draft gnd low gas pressure, 4 in. W.G. to 3 lbs. Type "G" natural gas burners, which are a multiple, refractory venturie, horizon tal burner, specially adapted to standby oil firing; or as special burners to fire kilns, dehydrators or other installations where the burners are subjected to extremely j>'gh temperatures. Operates successfully under natural or induced draft conditions ;!l low to intermediate gas pressures. Various types of pilot burners, panel boards, special burner applications, and mis cellaneous gas burner accessories. Write for catalogs and information. 1497 . METALBESTOS DIVISION Be Sure of Safe Gas Venting Use METALBESTOS-- the insulated vent Right for you . . . because Metalbestos is easily and quickly installed. Precision made couplers slip together without forcing . . . are tightly and permanently sealed without using mastic or cement. Ad justable lengths, adjustable elbows and other versatile fittings speed assembly and eliminate wasteful cutting and fitting. Your costs are lower, profits higher, because with Metalbestos you can make more installations per man per day. Right for your customers ... because Metalbestos assures safe, trouble-free venting for the lifetime of the house itself. Double-wall design provides an inner "hot stack" for strong draft, minimum condensation . . . and an air-insulated outer pipe to protect adjacent wall surfaces from dangerous overheating. Permanently tight joints and corrosion-resistant aluminum con struction are further reasons why Metalbestos can be installed and then forgotten. ' Send for free copy of VENT INSTALLATION HANDBOOK Based on the latest gas venting research, this pocket-size booklet contains com plete, up-to-date information on venting practices plus many helpful installation tips. Write today for your copy. No obligation. 1498 Heating Systems Gas Vent --i --te, metalbestos- DIVISION __________________________________ For every gas venting need specify METALBESTOS . . . the insulated vent Metalbestos is approved by Underwriters* Laboratories as a Type B gas vent. These important features assure correct venting: DOUBLE-WALL DESIGN ... an inner "hot stack" for strong draft, minimum condensation ... a cooler outer pipe for maximum protection of surrounding wall areas. QUICK COUPLERS . . . and adjustable fittings for fast, low-cost installation. DURABLE CONSTRUCTION . . . made entirely of corrosion-resistant aluminum . . . will never crack or break . . . makes a rigid, tightly sealed venting system which lasts the lifetime of the house itself. 1. Draft Hood Connector 2. QC Round Pipe 3. QC 90 Round Elbow 4. QC Round to Oval Tee 5. Oval Pipe 6. Oval to QC Round Adapter 7. QC Round Increaser 8. QC Round Tee SAFE WALL HEATER VENTING Inside 2 in. x 4 in. Stud Walls Metalbestos Type B-W Wall-Vent is ap proved by Underwriters' Laboratories, fric., for installation with only % in. clearance from combustible material. Its thin rectangular design permits this double-wall insulated vent to be placed w)thin a standard 2 in. x 4 in. stud wall without the expense of furring out or other special construction. Furnished in 3. 4 and 5-ft lengths. 9. Metalbestos Wall-Vent 10. QC 45 Round Adjustable Elbow 11. QC Round Adjustable Length 12. Adjustable Roof Flashing 13. Storm Collar 14. QC Belmont Top ' NOTE: QC Hound pipe and fittings are furnished 3 8in siees of in. to in. diameter. Oval Metalbestos 4and Wall-Vent are available in standard in. sise only. . 1499 ?033Heating Systems -LTo Siemon Manufacturing Company 1819 Holmes street Kansas City 8, Mo. Representatives in most Principal Cities Siemon Power-Flame Gas Burners FO Series-Gun Type Siemon Power Flame forced draft burn ers offer extreme flexibility. FG series gun type units are ideal where limited space is a factor such as Scotch Marine type boilers, narrow firebox heaters and the like. Series BFG units--block type--designed for use where high capacities are re- BFG seriesSpread-bladt type quired and minimum base heights for ment, are shipped as a package, factory installation are available. Both types wired and tested before shipment. See employ standard items of control equip- Cat. No. F.G-1010 and BFG-5158 HOURLY CAPACITIES AND SPECIFICATIONS Burner Model Gas Input MBTU/HB Min. Max. Gross Boiler Output ' 100% Rating Sq ft Sq Ft Steam Water Max BMP Gas Conn. Motor Type Control FG-500 FG-500E FG-750E FG-1Q00E FG-1600E FG-2200E FG-3000E BFG-3000E BFG-4500E BFG-60B0E BFG-9000E 75 140 300 300 300 650 650 1500 1500 - 1500 3000 4500 6000 175 330 500 500 500 1000 1600 2200 3000 3000 4500 6000 9000 460 900 1420 1420 2250 3000 4600 6500 9000 9000 . 13500 1SQ0O 27000 750 1400 2300 2300 3600 4800 7500 10400 14000 14000 21000 29000 43500 3.6 7 10 10 16 21 33 44 60 60 90 120 180 H' l' 1' 1' ltt' W 2' 2' 2W 2HW Z* 3* 4# Ho H H' H H H -M M M H H W -H Thermo-Relay Thermo-Relay Thermo-Relay Electronic Electronic Electronic Electronic Electronic Electronic Electronic Electronic Electronic Electronic A.G.A Listed 1000 Btu Gat 3* W. C. Pressure--Available for Mixed or L. P. Gases " Based on 70% Boiler Efficiency Siemon Combination Gas-Oil Burners FGO Series Siemon FGO Series units employ a tube within a tube principle to fire both fuels (gas and light oils) efficiently. Installa tion costs are reduced to a minimum since all units are packaged and factory wired and fire tested before shipment. All units are pressure atomizing type, simple to install, service and maintain. See Cat. No. FG0-515S Burner Model FGO-700E FGO-1000E FGO-1400E FGO-2200E FGO-3000E HOURLY CAPACITIES AND SPECIFICATIONS Gas Input MBTU/Hr Min. 400 650 650 1500 1500 Max. 700 1000 1400 2200 3000 Gross Boiler Oil #1,2,3 Gals. Output 100% Rating Max BHP Gas Conn P/HR Sq Ft Sq Ft Steam Water 3-5 5-7 5-10 10-16 10-22 2100 3000 4200 6600 9000 3875 4800 6750 10500 14000 15 20 28 44 60 W W 2* V 2H' 1000 Btu Gas ( Based on 70% Boiler Efficiency Motor Hp 1500 Heating Systems Burners. Gas The Sonner Burner Company Designers and Manufacturers of Gas Conversion Burners and Unit Heaters . ______Offices and Factories: Winfield, Kansas Type LSS Heat Machine Type L V SONNER Burner Type D SONNER Burner Sonner Gas Conversion Burners are a productof a quarter century of specializa tion in design and manufacture. A wide range of designs provides a Sonner Burner for domestic, commercial or industrial use. Consult Sonner Engi neering for advice. TYPE L-52 HEAT MACHINE is designed specifically for the conversion of resi dential heating plants to gas. Com pletely automatic burner is A.G.A. listed. Available in two sizes with capacities ranging from 75,000 to 400,000 Btu/hr. See Cat. 52-L-l. TYPE LV SONNER BURNER for large heating and power boilers, handles a wide range of fuels. Standard assemblies from 320,000 to 7,200,000 Btu/hr are described in Cat. 52-LV-l. Step fired as semblies are described in Cat. 50-LVS-I. TYPE D SONNER BURNER offers complete flexibility for all types and sizes of boilers and plants. Type "D" Burner Units can be readily manifolded into exactly the correct size and shape of burner for any kind of firebox. See Cat. 49-D-l. SONNER GAS FIRED UNIT HEATERS provide low cost automatic heating in commercial installations where space is at a premium. Approved by A.G.A. and Underwriters' Laboratories. Available in two sizes, 75,000 and 100,000 Btu/hr input. See Cat. 51-U-l. GAS OIL UNIT FOR COMMERCIAL AND INDUSTRIAL BOILERS, two fuel burning units each designed for one fuel natural gas, light fuel oils. Standard assemblies 280,000 to 2,800,000 BtuAr in put. See Cat. 52-CU-l. Unit Healer 1501 Sonner Gas Oil Unit i ' Heating Systems Burners, Gas and oa JOHN ZINK* ^CO. John Zink Company 4401 S'. Peoria -- Tulsa, Okla. Shreveport New Obleaks Corpus Chbisti Houston * San Antonio Lubbock Fort Worth Los Angeles ' See other page for additional offioes Heating Systems Burners. Gas and oa John Zink Company 4401 S. Peoria -- Tulsa, Okla. Boston . New Yobk . Pittsburgh Detroit. Chicago . St. Lorns . Omaha . Daula. . L.ttgs R^Tr __________________________ oee other page for additional offices stv rs SERIES STV GAS BURNER Ideal for heating boiler installations. From one head to fifty heads. Quiet, effi- cienfc and economical operation. Write for literature. * SERIES VR VERTICAL GAS BURNER This burner is of the "upshot" or vertical radiant type with multiple burner heads so designed as to entrain a certain amount of primary air from the total air entering through the louvre. The "VR" burners are especially designed to operate in boilers having low draft and small combustion space. Write for literature. FLOOR FURNACES A size for every home heating requirement. Small grille--fool proof--simple to operate--AGA approved--sturdy construction. Sizes--35,000; 50,000 and 65,000 Btu input. Write for literature. NEW SUSPENDED UNIT HEATER (Series D H S Fan Type) AGA approved for Natural, Mixed, Manufactured or LP Gas. For clean, safe trouble-free heating of industrial and commercial establishments. A complete packaged unit that is fully automatic. Conserves valuable floor space. Designed for an attractive addition to any store or shop. Write for literature. !! ill The John Zink Series YC Combination Gas and Oil Burner is recommended for boilers and process furnaces where maximum heat release at low excess air and high heat density is required. Features of the Series YC are Rugged Weather-Proof Construction; Easy to Remove Fuel Guns; Lightweight Fuel Guns; Burn Any Com mercial Fuel Oil; Burn Any Gas at Reasonable Pressure; Draft--Natural, Forced or Induced; Center Firing of Both Fuels; Will Operate with Either Fuel as well as in Combination; Can Be Equipped With Any Standard Type Controls. Also: SMOKELESS FIELD FLARE BURNERS 1502 CENTRAL GAS HEATERS (Horizontal-Vertical) A truly universal, efficient, simple and compact central heating unit. Fully auto matic, it is a complete packaged unit ready for installation. May be installed in the basement, attic, service closet or utility room. It is designed as a winter air conditioner with a summer switch to provide air circulation during warm weather. Two models available. Write for literature. Also: WALL HEATERS, CONVERSION BURNERS, ATTIC FANS 1503 Heating Systems Burners, Gas The Webster Engineering Company 115 South Frisco St., P.Q, Box 2168 Tulsa, Oklahoma Division of SURFACE COMBUSTION CORPORATION, TOLEDO, OHIO Heating Systems Specialties, Oil Burner Eddington Metal Specialty Company Eddington, Pennsylvania Filters, Nozzles, Valves, Stabilizers & Air Cones, Strainers, Adaptors, Inspection Mirrors, Servicemens' Nozzle Kits, Combustion Heads Low Pressure Atmospheric Gas Burner with full venturi mixers and Meehanite alloy flame retention nozzles. Compact and easy to install, the assemblies are available in any desired size and shape. WEBSTER DUONETIC* Dual Fuel Burner combining the econ omy, efficiency and trouble-free opera tion of the WEBSTER KINETIC Gas Burner with a light oil burner with unique provisions to prevent coking of the oil nozzles. Capacities to 2.5 million Btu/hr. WEBSTER ROTONETIC* WEBSTER DYNETIC* Dual Fuel Burner utilizing low pressure gas and any grade of commercial fuel oil under forced draft. Completely as sembled, wired and tested at the factory; Forced Draft Gas Burner. A completely packaged unit available from 800,Ow 14,000.000 Btu/hr with low pressure gas. the units are available to 300 horse power. WEBSTER ALSO MANUFACTURES: Series F600 and Series 650 Vertical Gas Burn ers for Heal lug and Power Boilers. Series 340 Gas Burners for Vertical Boilers. VI and Webster Rectilinear High Pressure Inspirators for Boilers, Kilns, Sti . Dryers, Etc. Series 200 and Series R Combination Gas and Oil Burners for row Boilers. SALES and SERVICE IN ALL PRINCIPAL CITIES Trade Mark 1504 OIL BURNER NOZZLE Supplied standard with "Hollow," "Semi-Hollow," and "Solid" spray patterns. Special series nozzles can be custom made for specific Combustion Heads, Boiler Burner Units, or Burners. Made of Stainless Steel; factory-tested for spray angle, atomization, and actual rated capacity- Large ca pacity Monel Strainer keeps orifice and slots from plugging. OIL BURNER FILTERS For heating oils in pressure and gravity type oil burners, space heaters, water heaters, stoves, and ranges. Casing . made from die-cast aiuminum. Cartridge has staggered surface for greater filtering area. May be replaced easily--only one bolt to remove; pipe connections need not be disturbed. Complete unit interchangeable with other makes. DIMENSIONAL SPECIFICATIONS OF FILTERS MODEL NO. HEIGHT S-252 6Ms S-254 5% DIAM ETER AHs 3*6 WEIGHT 1 lb 10 oz. 1 lb 5 oz. INLET * OUTLET * SURFACE AREA 98 sq in. 72 sq in. UNDER WRITERS APPROVED 25 gph 25 gph EDCO SINGLE ADJUSTMENT DUPLEX VALVES Designed to regulate fuel pressure at nozzle and to make positive cut off of oil flow to nozzle during burner "off" period. Outer casting is close non-porous brass; valve needles are stainless steel; valve seat is special alloy bronze. Con form to UL standards for operation up to 150 lbs oil pressure. 1505 I - Heating Systems Burners.on Automatic Burner Corp. 1823 W.Carroll Ave. Chicago 12, HI. "THE STANDARD THE INDUSTRY" MODEL 52A MODEL 55A Domestic Conversion Oil Burner Famous for many years as the gun type oil burner that combines maximum effi ciency and economy with trouble-free operation. The heavy gage, drawn steel housing gives a smoother and quieter performance. Some of the exclusive fea tures are the ABC Choke, Spinner and Coupling Assembly. This burner has an unusually attractive appearance in any type of installation. Capacity 0.6 to 5.0 gph. .. For Packaged Heating Units This more compact pressure type burner is exceptionally easy to adapt to a wide range of heating units. It fits vestibules measuring only 9% in. and mounts di rectly to the unit by means of a flange. Among its many features are: high effi ciency, quietness of operation, ease of servicing, and dependability over many years of use. Capacity 0.6 to 3 gph. MFoOr CDoEmLme5r4cial and Large Residential Use More compact yet more efficient for heat ing and hot water in stores, apartment buildings and similar installations. In corporates an easily adjustable hinged damper on right hand side as well as usual air intake on pump side for more exact air adjustment at every capacity. Specially designed, double - inlet fan brings air into Lousing from both sides. With 2-stage Electric Solenoid Fuel Unit. MODEL 53 Capacity 4 to 10 gph. Industrial Oil Burner Provides dependable, economical oil heat for small to medium sized factories, in stitutions, etc. Built-iD Bafety combus tion control eliminates need for any stack relay; positive, built-in automatic elec tric oil cutoff eliminates after-burn . . . has dual ignition and dual nozzles, hinged transformers, two-stage Electric Sole noid Fuel Unit. Capacity 9 to 15 gph. 1 Heating Systems i Burners, on Enterprise Engine & Machinery Co. A SUBSIDIARY OF GENERAL METALS CORPORATION 18th & Florida Streets, San Francisco 10, California Distributors in Principal Cities ENTERPRISE HORIZONTAL ROTARY BURNERS--OIL, COMBINATION OIL--GAS BURNER CAPACITIES--150,000 BTU OIL 1,000 BTU GAS B U R N E R SIZE O IL U. S.'GALS. PER HR. GAS CU FT PER HOUR .STEAM E D R | 240 Gtu HOT WATER E D R 150 Gtu LGSSTEAM PER HOUR ft* CL aa aa ow s s j o A AA A 4 600 13 1,800 2,880 450 A 'A 7 1,050 23 3,200 5,120 795 C A 15 2,250 50 6,950 11,120 1,270 E A 20 3,000 67 9.310 14,900 2,310 F H 28 4.200 93 12,930 20,700 3,270 G 35 5,250 116 16,125 25,800 4,000 H 50 7,500 166 23,075 36,900 5,725 J 2 70 10,500 233 32,390 51,800 8,040 K 3 100 15.000 333 46,290 74,000 11,490 L 3 135 20,250 450 62,550 100,000 15,525 M 5 200 30.000 666 92,575 148,100 22,975 All maximum capacities are necessarily approximate* Burners installed with adequate draft provisions and correct furnace volume, properly designed, will de velop capacities indicated, at sea level. APPLICATION Enterprise Horizontal Rotary Burners are specifically designed for Commercial and industrial use. Commercial heating includes heating plants in all types of buildings larger than private homes, including apartment houses, hotels, hospi tals, schools, green houses, public build ings, offices, manufacturing plants. Indus trial applications include furnaces, kilns, driers, etc. MULTIPLE TYPES Manual--To be started, regulated and stopped by operator. Semi-Automatic--Started and stopped by operator, but automatically regulated by temperature or pressure control. Full-Automatic--Burner automatically starts, stops, and is regulated to provide desired temperatures or steam pressure. Fixed fire start available on smaller sizes. Low fire start for high-low or full modulating control on all sizes. All burners available with either Stand ard gear pump or P. D. Metering Pump or sNeot)n. -pump (for use with separate pump Any grade of fuel oil is burned efficiently ~"No. 6 (Bunker C) fuel is burned by burners equipped with oil heating sys tem. COMBINATION OIL-GAS BURNERS All of the above types of burners are mcorporated in combination type burner to burn either fuel oil or gas. Gas may be natural, manufactured, or L. P. gas. STANDARD EQUIPMENT All full-automatic burners are furnished with: V-Belt drive, with known advan tages of.standard electric motors. Gas-electric ignition--dual ignition on sizes G to M. Interconnected linkage to provide pro portionate mixing of oil and air or gas and air at all firing rates. Optional open type or angular vane air nozzles for flame control. Copper tubing--provides free flow of oil with minimum connections. Operating and combustion safety con trols--oil burners, temperature or elec tronic type--Combination Oil-Gas burn ers, electronic controls exclusively. SPECIAL FEATURES The Enterprise P. D. Metering Pump provides exact delivery of oil to the burner by positive displacement, rather than through a metering valve. This defi nitely insures correct oil supply and air proportioning regardless of the viscosity of the oil, resulting in high efficiency. Burner hinges are provided with leak proof "O" rings rather than conven tional packing glands. FULLY APPROVED Enterprise Oil Burners have been tested, approved, and listed as standard by Underwriters1 Laboratories, Inc. and by other recognized boards and bureaus of safety, measures, and controls. ENGINEERS will be provided with com plete engineering information, either by manufacturers or qualified distributors, upon request. 1507 Heating Systems Burners, Oil S. T. Johnson Co. Builders of fine Oil Burners.. .since 1903 Residential Ccmmercial Industrial Joilmen BOd UAtWtA. 940 Arlington Ave. Oakland 8, California Church Road, Bridgeport, Pennsylvania BANKHEAT BURNER Pressure - atomizing, fully - automatic. Built with the finest available safety and operating controls. A time-testea burner notable for its economy, de pendability and efficiency. Highly adapt able. Ideal for "conversions." Bankheat Burners power the complete Johnson units shown below. SIZE BH-0 BH-0A BH-1A BH-3A CAP. GPH Min. Max. .8 2.25 1.0 3.0 2.0 5.5 3.0 7.5 4.0 10.0 5.0 15.0 7.5 18.0 MAX BOILER RATING Steam Water Hp 900 1300 2300 3100 4150 6200 7500 1450 2100 3650 4950 6650 9900 12000 m 9 16 30 45 54 BANKHEAT OIL- and-GAS BURNER In areas where low-cost gas is available on a part time basis Bankheat Dual-Fuel Oil-and-Gas Burners offer the greatest possible economy and efficiency. They are equipped with finest electronic auto matic controls. SIZE 0A 0A 1A 2 2A 3 3A MAX FIRING MAX BOILER OUTPUT RATE Oil Gas CFB Steam Water eph 1000 Btu Sq Ft Sq Ft HP 2H 315 3 420 5*4 770 7*4 1050 10 1400 15 2100 18 2520 900 1300 2300 3100 4150 6200 7500 1450 2100 3650 4950 6650 9900 12000 16 45 54 Heating Systems Burners, on S. T. Johnson Go. Buiiders of fine Oil Burners.. .since 1903 Residential Commercial Industrial 940 Arlington Ave. Oakland 8, California Church Road Bridgeport, Pennsylvania MODEL 53 fully AUTOMATIC METERING PUMP BURNER This revolutionary new Johnson Burner will automatically maintain a fixed Air-Fuel Ratio regardless of variations in oil temperature and viscosity, thus virtually eliminating the problem of "Cold Starts." Built with a positivedisplacement metering pump plus other new improvements which make it ex ceptionally economical, dependable and easy to service ... a worthy addition to the distinguished line-up of Johnson Burners. SIZE AND BHP 25 50 100 150 200 300 400 MOTOR HP Vi H H m 2 3 4 GPH OIL IH 15 30 45 60 90 120 so irr . STEAM RADIATION 3500 7000 14000 21000 28000 42000 56000 Model SS Metering Pump Oil Burner MODEL 53 METERING PUMP DUAL-FUEL fully AUTOMATIC OlL-and-GAS BURNER Offers a choice of fuels in addition to the other advantages of the new Model 53 . . . thus making it possible in many areas to effect worth while fuel econ omies. Model SS Metering Pump Dual-Fuel OH-and-Gae Burner OTHER HEAVY-DUTY JOHNSON BURNERS AVAILABLE Heatlvx House Heaters, 85000 and 1500CO Btu Aqvlux Water Heaters, Cap. 100 to 60 Gpk 1508 TYPES 28 AND 30 ARE AVAILABLE IN THE SAME SIZES AND CAPACITIES AS MODEL S3 1509 Heating Systems oTSdo.* Ray Oil Burner Co. Since 1872 Atlantic Seaboard Division 1301 San Jose Avenue 629 Grove Street San Francisco 12.-Cal. Jersey City 2. N. J. There is a RAY Burner for every Heating Purpose. RAY FORCED DRAFT PACKAGED BURNER A factory assembled unit readily applied to Scotch Marine type boilers of proper design for 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 panel and pre-piping completely factory as sembled for quick and easy installation to the boiler. Oil components may be selected to burn any grade of oil FD-ARC Size #6 fully with the secondary air control providing increased efficiency automatic, combination gas-oil, Forced Draft even with the difficult-to-burn catalytic residual #6 fuel oils. Packaged Burner. From 59 to 456 certified output horsepower. RAY COMBINATION OIL-GAS BURNERS ARC-144 Model SO for heavy oil and Low Pres- Type PC for OH and Low Pressure Gas Type AR-HN Combination OH and High Pres sure Gas sure Gas ' sure ARC-MODEL 50. Consists of a rotary type oil burner of Ray conventional design coupled with a gas housing for low pressure gas, from 2 in. WC to 10 in. WC. 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 concen tric with the nozzle. Change-over requires less than one minute. Available to burn any grade of oil in 10 sizes with capacities to 31,500,000 Btu/hr. TYPE HN for gas pressures above 1 lb/sq in. may be used alone or in combina tion with a Ray Oil Burner. Built in eleverf sizes; in capacities to 43,000,000 Btu/hr. TYPE PC. Combination gas-oil burner .of the pressure atomizing type. Available in three sizes with capacities from 560,000 to 2,500,000 Btu/hr. RAY DOMESTIC AND MARINE BURNERS Steam Turbine Drive, Fully Automatic, Type Type TG, all grade* oil. Tested and approved for Ray Warm Air Oil Furnace RAY PJPR,ESSS! UoRr ElighAteTr OoHMIZING V. S. OIL Navy Service. BURNERS Fully automatic for No. 2 oil- or lWigAhRteMr. AAICR oFrUDRCNA; CcaEpSacBituieislt 1intofiv1e8sgizaellso,nwsitpheirnhpouutrc. apacities of 105,000; 14,,,0n,UrWw. 2R3A0Y,00O0;IL35W0,A00T0E; R45H0,E00A0TBERtuS. Four sizes. Capacities: 35, 45, 60 and 75 gal. Maxi.m,u,m- recovery rates: 100 to 240 gph. 1510 Heating Systems Burners. Oil and Gas Ray Oil Burner Co. Since 1872 tfuot/ VtJLIUc San Francisco 12, Cal. 629 Grove Street Distributors in All Principal Cities of the World Jersey City 2, N. J. Consult your local Telephone Directory Products: A complete line of Horizontal Rotary and Pressure Atomizing Oil Burners; Combination Oil-or-Gas Burners; Industrial Gas Burners; Forced Draft, packaged Burners; Oil Burning Water Heaters; Warm Air Furnaces, Commercial Ranges. Type AR-tU Size 10 for No. 6 oH. Available in 10 sizes from i to tlQ gph. Fully automatic. FuUy Automatic Type AR-184, for No. 6 oil. 1 to 1000 Boiler kp- Type AG. Manual, Semi-au tomatic control. . Type ARJP, FuUy Au tomatic for heavy oH where gas for ignition not aoaHabU. RAY HORIZONTAL ROTARY OIL BURNERS Built in fully automatic, semi-automatic and manual types; in sizes from 1 to 1000 Boiler hp; to burn all grades of fuel oil. Standard models include both direct and belt drives--the latter being recommended for use where other than 50 or 60 Cycles AC, or only DC is available. Types for straight elec tric or straight gas ignition; pump or gravity feeds. Direct drive types include a steam turbine driven model. All fully automatic types for heavy oil incoiporate the Ray Dual Pump and Reservoir, with the Ray VISuOSITY Valve, a patented, exclusive feature which automatically meters the correct amount of fuel at all times, regardless of changes in FuUy Automatic^ tSTto viscosity of the oil due to temperature variations. All larger ioo gph. ` sizes employ dual ignition system, consisting of dual high-volt age transformers, dual electric ignitors and dual gas valves. Fully automatic sizes 9 and 10 include as standard equipment electronic pilot and flame failure control. Burner Size ""JP" XPJ XPj-i XP-2 i i i 1 Oil Capacity U. S. Gallons Max. 3 4 38 8 18 Equivalent Boiler HP inin. 3 3 9 25 Max. 9 12 25 56 Equivalent Lbs. Steam Generated Min. Max. 110 325 110 430 325 865 865 1950 Heat Capacity Input Thou. Btu Oil or 1000 Btu Gas Min. Max. 140 140 420 1120 420 560 1120 2500 Equivalent Sq. Ft Steam Radiation Min. 438 438 1310 3500 Max. 1310 1750 3500 7900 ooc 00 0 is'o i i 0.5 0.5 1 2 2.5 2.5 2.5 5 1 2 i i t 4 5 8 11 15 22 2 2 3 7 13 17 27 8 60 290 75 8 60 290 75 8 110 290 150 16 230 580 300 35 460 1250 50 580 1720 600 750 72 930 2500 1200 375 375 375 750 1650 2250 3300 234 234 469 938 1870 2350 3750 1170 1170 1170 2350 5170 7030 10,300 1 10 li 12 2 15 3 25 33 50 67 100 35 40 50 85 110 1150 3800 165 1400 5800 225 1720 7750 335 2900 11500 1500 1800 2250 3750 4950 7500 10000 15000 4690 5620 7030 11700 15500 23400 31400 46900 NOTE;: 5 35 7* 50 7} 75 These ratings 150 210 320 120 165 250 500 700 1000 4000 5800 8700 17400 24400 37000 5250 7500 11250 22500 31500 are predicated upon specific conditions of draft and furnaoe volume. --_ It may be per missible, under desirable conditions, to operate at higher rates, or advisable under restricted condi tions, to operate at reduced rates. Heating capacities are based upon 150,000 Btu per gal of oil for rotary burners and 140,000 Btu per sal of oil for pressure atomizing burners and upon an overall boiler efficiency of 75 per cent. 1511 0Heating Systems """*' C. L. automatic Company 2010-18 S. Halsted Street, Chicago 8, Illinois DOMESTIC, COMMERCIAL AND INDUSTRIAL OIL BURNERS FOR ALL GRADES OF FUEL OILS, FOR SMALLEST TO LARGEST BUILDINGS. DOMESTIC AND SMALL COMMERCIAL AND INDUSTRIAL GAS BURNERS For No- * or No. * 0*I* For JVo. 4 or No. 5 Hams For ATo. for No. 6 llcimiat OH* SHELL COMBUSTION HEAD OIL BURNERS for No. 2 or No. 3 CATALYTIC OILS 2 models 1.00 to 3.00 gph. The Shell head gives Higher CO* values, lower stack temperature, freedom from smoke and soot. Draft requirements are not critical. Results in a saving of 14 per cent to 36 per cent of fuel require ments. Perfected combustion keeps boil ers clean. Precision parts and sound engineering insure quiet operation free from vibration or pulsation. Here is the ideal replacement oil burner for systems using light catalytic fuel oils. RAYFIELD BURNERS for No. 4 or No. 5 HEAVY OILS Model JR.--1.00 to 5.00 gph. Model D4--3.00 to 12.00 gph. These fully automatic burners are de signed to provide efficient heating with the cheaper grades of oil. Both modeIs are all-electnc operating, self-lubricat ing and have self-cleaning nozzles for Jong, trouble-free service. By utilizing 'the low-priced fuels, these units keep heating costs to a minimum. Ideal for smaller commercial and industrial appli cation. RAYFIELD-STAFFCO ROTARY BURNERS FOR NO. 5 and NO. 6 HEAVIEST FUEL OILS 9 sizes ranging from 10 to 165 gph firing rates These sturdy burners, known and used all over the world, give excellent results and are built for long life with minimum service. Available with many types o| controls including mechanical, electrical and electronic types. All equipped with Regulating Valves to maintain constant oil flow regardless of oil viscosity or temperature. Adjustable air vanes to produce any flame shape or size desired- ATMOSPHERIC AND GUN TYPE GAS BURNERS 1512 Heating Systems Burners, on York-Shipley, Inc. Main Office and Plants--York 16, Pennsylvania OIL-FIRED EQUIPMENT FOR INDUSTRY FUEL BURNING SYSTEMS STEAM-PAK GENERATORS Model AHPM York Power Horizontal Burner mounted in position in Windbox with ignition assem bly and secondary air door in position. These are two of the elements of York-Power's new coordinated In dustrial Fuel Burning Systems. York-Power Co-ordinated Industrial Fuel Burning Systems make available for the first time factory packaged industrial fuel burning systems with tne basic com ponents pre-wired and mounted in posi tion. The complete system includes: York-Power Horizontal Rotary Burn ers in a full range of sizes from 45 to 400 boiler hp, either oil-fired or combination oil or gas firing. The oil burner burns No. 3, 5, or 6 oil and with manual, semi automatic, or full modulating control. York-Power Control Boards---Pre wired control panels for single or multi ple burner installations. Also draft con trol panels and induced draft control panels. Panels sized for neat installa tion. All controls mounted and wired. Panels built for various types of control circuits and specified according to instal lation requirements. York-Power Windbox--Factory-de signed and built windbox assembly with burner mounting plate and secondary j air door in position. Eliminates need for . pitting and special refractory work. i . York-Power Trim--Kits of necessary valves, gages, thermometers, fuel oil beaters, temperature controllers, and low water cut-offs to complete system. All York-Shipley Industrial products are engineered and installed by local distributors who have been selected be cause of their knowledge of engineering equipment using heavy oils and gas. Model SPLrSOS low-pressure boiler for heat ing applications. A three-pass, down-draft, horizontal fire tube design. Uses Ho. S oil. Steam-Pak Generators are built both for low-pressure heating load and for high-pressure process load, in sizes from 15 hp up. Using fuel oils No. 3, 5, and 6, or gas or combination they require only a low-cost vent to remove products of combustion. With about half the size, weight, and installation cost as compared to brick-set boilers of comparable capacity, SteamPak Generators require only four simple service connections, and are completely wired, piped, and pre-tested at the factory. Ready to operate when de livered. The Steam-Pak Generator is an effi cient unit, combining the oil burner and boiler in one package. It is designed to operate at peak efficiency through the entire firing range- This is accomplished with the Iris Shutter and modulating pump. A COMPLETE LINE OF INDUSTRIAL COMMERCIAL AND RESIDENTIAL EQUIPMENT York-Shipley, Inc. builds a complete line of automatic heating equipment. Be side the Horizontal Rotary Burners and Steam-Pak Generators for industrial and commercial use described here, we offer the famous York-Heat boiler-units, winter air conditioners, water heaters, and con version burners for either oil or gas. INTERNATIONAL HEATING & VENTILATING EXPOSITION THE AIR CONDITIONING EXPOSITION Permanent Address--480 Lexington Ave., New York 17, N. Y. EXPOSITIONS HELD Chicago, 1953; Philadelphia, 1951; Chi cago, 1949; New York, 1948; Cleveland, 1947-1940; New York, 1938; Chicago, 1936; New York, 1934; Cleveland, 1932; Philadelphia, 1930. . FUTURE SCHEDULE The 12th Exposition is scheduled for Commercial Museum & Convention Hall, Philadelphia, Pa., January 24 to 28, 1955. UNDER AUSPICES OF A.S.H.V.E. These Expositions have been and will be held co-incident with the annual meetings of The American Society of Heating and Ventilating Engineers 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 exhibitors. EXHIBITS These range from and comprise all the types of articles discussed or advertised in this copy of The A.S.H.V.E. Guide. 1. The Combustion Group: Furnaces, burners (coal, oil and gas), grates, stokers, boilers, radiators (vari ous types), refractories and auxiliaries. 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 appa ratus, contingent apparatus and refrig erants. 10. The Central Heating Group: Apparatus and materials especially de signed or adapted to the uses of central heating and central heating station sup plies. 11. The Insulating Group: Structural insulators (refractory and cellulose materials), asbestos, magnesia clays and combinations thereof, pipe and conduit covering, etc., weather-strip ping, 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 Equipment Group. and . General 14. Books and Publications. VISITOR ATTENDANCE 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: Attendance is by invitation and regis tration only, thereby presenting a selected audience. Included are con tractors, dealers, jobbers, supply houses, home owners, industrial users, professional and service organisations, public utilities, real estate management concerns, etc. A detailed analysis of registered'attendance is available on request. 6. The Air Group: Warm Air furnaces and stoves, registers and grilles, cooling towers, air filters, motors, fans, blowers, conditioning equipment, ventilators (room and indus trial types), unit heaters, etc. 7. The Air Conditioning Group: Equipment which circulates and filters the air, in summer dehumidifies and cools; in winter heats and humidifies, aDd does all these in proper season for com plete, all year-round air conditioning. Industrial Expositions in America lead the expositions of the world m style, business effectiveness, industrial influence and educational value. This Exposition stands among the leaders in Industrial Expositions in America. V is an educational institution wnicn brings together the research develop ments and improvements in equip0 and materials for use in heating, vent; j lating and air conditioning all types buildings. 1514 Heating Systems sSiK'" Aerco Corporation 214 Lafayette Place, P.O. Box 428 Englewood, N. J. A Compact Storage Water Heater with Internal Compensator (to anticipate and control heat transfer rate) having instant recovery of outlet temperature after peak demands, which: . Anticipates changes in required steam jlow before the actual heat transfer takes place. Meiers the steam flow accurately in direct proportion with load. Prevents surges in steam flow, elimi nating need for large storage. Maintains ACCURATEcontrol of out let water temperature. Prevents OVERRIDE of outlet tem wpeartaetrufrleowo.n sudden interruption of For uniformly varying loads (i.e. Hos-. pital General Water Supply), because of the ability of the above neater to prevent surges of steam input, it 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: * mauds St0mge Vlume for Peak de- Minimum steam input for required load. Accurate controlled outlet water tem perature under all load conditions. CONSTRUCTION Figure S--Aerco Compact Storage Water Heater in Pcoummbpin. ation toith. Accumulator and Recirculating Shell fabricated to ASME Code Standards, of Flanged 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, 5 to 438 gpm. OPERATION Cold water enters top, flows down through the Compensator, then up across steam roils to discharge at top. Steam feeds into coila through Steam Riser and leaves through Condensate Return. . Compensator anticipates and controls heat transfer rate by sensing changes id how or incoming temperature before water passes over the heating coils. It accom plishes this by causing variations of temperature to occur at the Regulator bulb JTbich are definitely related to changes in flow and incoming temperature as well as TMe final temperature. , Ask for Bulletin #22 for complete capacity data and sizes. 1515 Heating Systems Hot wter Bell and Gossett Company Morton Grove, Illinois HYDRO-FLO HOT WATER SYSTEMS AND SPECIALTIES B & G Booster Pumps The B & G Booster is the basic unit of a B <fc G Hydro-Flo Forced Hot Water Heating System. It is built as a hori zontally driven unit for sound engineer ing reasons which have demonstrated their practical value in thousands of installations. This construction makes possible many desirable, exclusive fea tures. For example, the patented water tight Seal eliminates need for a stuffing box. This Seal positively prevents entry of water into bearings. Shaft is of highly polished, hardened machine steel. The close-fitted Impeller makes eveTy revolu tion count by holding water slippage to a minimum. Oil Lubricated Bearings . B & G Angle Flo-Control Valves This valve, installed in the main, shuts off circulation to radiators when heat is not needed, permitting summer opera tion of a B & G Indirect Water Heater. It also helps maintain a uniform room temperature during the heating season. B & G Monoflo Fittings B & G Monoflo Fittings permit the use of a single pipe main instead of the conventional flow and return lines. They are installed at the junction of the radiator risers to the single main and assure the diversion of the proper amount of heated water into each radiator. Sav ings in space, labor and materials are obviously effected. Available in cast- iron and copper. . B & G Motorized Valves Thermostatically operated valves used to control boiler water flow through individual circuits of zoned heating systems. B & G Boosters, have a genuine oilcirculating lubrication system--one of the greatest reasons for quiet dependaubplefr,oemcotnhoemoicilawl oepllebryatwioono. l fiObriel iswdicrkaiwnng and dropped on the horizontal bearing ana uiuppeu vn mo,rrnAc m--otor----o---i-l--wis surfaces. Medium grade motor oil is used and only a few drops at infrequent intervals required. SEE THE B & G HANDBOOK FOR COMPLETE DESIGNING DATA jj & G Universal Pumps _Des.igned for forced hot wate , -jj. systems in apartment and om mgs. factories, schools; etc. tne stallation can be operated as a m B sW--winHitgghllCecizrocnuelauotiirodnivortifdpneumdmri_mnp__fett_od several zn, water in ceacu circuit controlled by a B & G Motorized Valve, operated by a zone thermostat- 1516 Bell and Gossett Company Heating Systems Hot Water Heating Heat Transfer HOT WATER SYSTE1 S AND SPECIALTIES B & G Relief Valves Designed and built to ASME require ments. Tested by National Board--la belled with ASME symbol. B & G Type "CWD" Radiation Heater For relieving excess boiler pressures in hot water heating systems, and in the lines of service water systems. B <fe G Relief Valves have the design features which assure dependable service. A "shell and tube" heat exchanger, installed below the water line of a steam boiler. Hot boiler water is pumped by a B & G Booster through the shell, thereby heating water for the heating system, which is pumped through tubes of Heater. B & G Reducing Valves Pumping the water through both heater and heating system affords excellent temperature control, and permits use of much smaller pipe and fittings. All working parts brass, with built-in strainer. Easily adjusted to meet vary ing building heights. Also high pressure reducing valves for protection of plumb ing fixtures. B & G Type "SD" Instantaneous Water Heaters B & G Comfort Control System For heating water with steam. Ideal for industrial plants or wherever large volumes of hot water are required con tinuously for service water supply or pro cess 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. Outdoor type, wind-compensating tem perature control. The Regulator pro jects through the building wall, with the indoor end warmed by water in the radiation circuit. A email amount of this heat is conducted to the outside end, where it is dissipated at a rate dependent upon temperature and wind velocity. This heat dissipation governs the Control Valve, which permits hot boiler water to enter the system in required amounts. B & G Centrifugal Pumps Design and construction based on years of experience in the industrial field. Rugged, compact units--built to with stand strain of continuous operation. Semi-open or enclosed impellers--motors flexible coupled or integral with pump. <-- B & G Refrigeration Components A very flexible line of direct expansion evaporators, condensers, liquid receiv ers, combination liquid receivers and subcoolers for refrigeration purposes are now available. Special alloys may be incorporated in the units for those critical heat transfer applications. Heating Systems Engineering 23, MorP ASME FABRICATION Heating Systems am Water Taco Heaters, Incorporated . 137 South St., Providence 3, R. I. Taco Heaters op Canada, Ltd., 24 Adelaide St., W., Toronto Accurate Design Information on Panel Heating .. floor, ceiling, snow removal FRE-FLO INSTANTANEOUS WATER HEATER Easily cleaned, straight tube with re movable cover plate and floating head. Designed for heavy loads and fouling fluids. Standard sizes from 200 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 fouling requires complete access for cleaning. FRE-FLO V-T STORAGE WATER HEATER Sizes from 100 gph to 2500 gph. Used with boiler water or low pressure steam. Installed vertically or diagonally, easily cleaned. FRE-FLO RADIATION CONVERTER Complete range of sizes. Used with steam or boiler water. Cast iron head, steel shell, copper U tubes and bronze tube supports or baffles. ---------j-------- ~i----t-- f .--`------1--------4--^ FRE-FLO SUCTION OIL HEATER (For any heavy viscous fluids) Large tubes; Triangular, or square pitch with range of sizes, ferrous or non ferrous 45 deg baffles. m Simplified design tables, based on current scientific engineering practices, have been designed to avoid long and tedious calculations. Installations made in accordance with their recommendations, assure satisfactory and economical results. Send for new 60 page catalog which has all this information on Taco products. Heat Exchangers ... Big or Small Horizontal Circulators ur ... All sizes available. FRE-FLO OIL PREHEATER Straight tubes with ferrous materials. P.__r_o_v_id__ed with ' removable bonnets. Ferrous or noil pansion joint when required. CATALOGUE AVAILABLE ON REQUEST 1518 'l'here is a storage or tankless type Taco ksat exchanger for every job--residential. aPartment, commercial. o. r ind-u--s--t-r-i-a--l-.---- , Taco circulators, both standard and high duty, are quiet, rugged and power ftounl.s fPoarckqeudiciknlyscpheacniaglliyngdeflsainggneedsiczeasr-. 1519 Heating Systems Hot w.te, H. A. Thrush & Company _ Peru, Indiana_.. Kepreseniaiires m Principal Cities ' FORCED CIRCULATING THRUSH FLOW CONTROL SYSTEM OF HOT WATER HEATING AND HEATING SPECIALTIES Horizontal Water Circulator Thrush Flow Control System of Hot Water Heat assures continuous radiant heat whether used with radiant panels, convectors, radiant baseboards or radia tors. Circulation is forced and opera tion is entirely automatic. It automati cally compensates for outdoor weather changes. Hot water for kitchen, laun dry and bath, both summer and winter are provided by the heating plant boiler. Piping plans and engineering assistance are available to the trade. THRUSH WATER CIRCULATORS Forced circulating pumps for Hot Water Heating and Domestic Water Systems. Insure uniform heating. Quiet and efficient, long lived and vibration-free. Sealed-in lubrication. Made in 6 sizes, 1 in., V/ in., l}$ in., 2 in., 23^ in., and 3 in. Hi-Head Horizontal Thrush Water Circulators, designed for use with radiant baseboards, convectors, radiant panels, etc., which require higher heaas, are also available in 1 in., in., and 13^ in. sizes. THRUSH FLOW CONTROL VALVES Special check valves for use on 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. Available with Air Tube which vents air from boiler into pressure tack, greatly improving heating efficiency by eliminating air from the system. 1 in. through in. valves also available with solder type outlet unions. Also made in angle type with or without air tube and in horizontal type for zoning. Made in six sizes, 1 in., 1J in., If in., 2 in., 2| in. and 3 in. . THRUSH PRESSURE TANKS NOW HAVE VACUUM BREAKER rw Prepare Tank Genuino Thrush Pressure Tanks are air tight... tested under WithVacuum Breaker pressure... and equipped with the. convenient Thrush Vacuum Breaker at no extra cost. Easy to drain if waterlogged. Bronze or iron J tn., J tn., and 1 in. THRUSH AUTOMATIC FILLING VALVES AND LOW PRESSURE RELIEF VALVES Whenever system pressure drops below 12 lbs, city water pressure will auto matically open the Thrush Automatic Filling Valve and admit water until the system is filled. Thrush Relief Valves protect heating boilers from excess pressures. Large metal diaphragm assures positive closing and opening. ,* ti. A. Thrush & Company Heating Systems Hot Water ASME APPROVED NO. 46 THRUSH SAFETY RELIEF VALVE FOR HOT WATER HEATING SYSTEMS Rated output of 283,800 Btu based on steam capacity discharge. Primarily a water relief valve designed to serve double duty of relieving water, as well as steam should critically high tempera tures occur. Testing lever. 30 lbs pres sure. % in. inlet, 1 in. outlet. Patent No. l.lSOfiiO THRUSH WATER HEATERS Highly efficient heat exchangers or con verters. Fifteen sizes, for Hot Water or Steam. Pressure up to 150 lb water, 50 lb steam. Straight tubes readily cleanable. Provide Domestic Hot Water at low cost. Also used industrially for heating or cooling liquids. No. 75 THRUSH HIGH PRESSURE WATER RELIEF VALVES To, protect hot water heaters, range boilers and automatic water heaters from excess pressure. Factory setting 85 lb. Adjustable at factory to 150 Id maximum. 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 develop. A fusible element melts at 210 F. Both types are designed for use in the hot water outlet line. THRUSH MANIFOLDS AND BALANCING VALVES Thrush Manifolds save timej space and labor installing Radiant Heatmg. Avail able in 1 in. and in. sizes, each with two, three or four % in. or 34 >n- threaded branch outlets. Ends have solder con nections. Manifold with Balancing Valves as shown above is used in return lines only. Used in supply lines without valves. Balancing Valves permit indi vidual filling of each coil, eliminate air quickly and save time. Flared fittings for % in. and 34 in. tubing. ADJUSTABLE THRUSH SUPPLY TEES FOR ONE PIPE SYSTEMS Provide exact balancing of forced circu lating one-pipe hot water heating sys tems. Easily adjusted. When branch flow is cut down main flow is increased, ft t. Patent Not.iOi, --Bronze Patent No. 2598143 not retarded. Available in bronze with solder connections for use with copper pipe and in threaded'cast iron for steel pipe. Non-adjustable tees also available. . NO. 5 HOT WATER AIR VALVE No. 6 Thrush Air Valve An inexpensive, dependable, automatic air vent for Hot Water It tn Bos coils, convectors, radiators, unit heaters, and high points of mains. Tapping in., I.P.T. THRUSH TANK DRAIN Combines Drain Valve and Vacuum Breaker in one handy, inexpensive fitting. Removing plug admits air to permit quick draining of waterlogged tank. ___mTiinr WRITE FOR NEW CONDENSED CATALOG 1521 Th Tani Drain Heating Systems Pumps allROlk Aurora Pump Company Subsidiary of the New York Air Brake Company aIIRQ^ CUuKi^j, 40 Loucks Street, Aurora (Chicago Suburb) Illinois w - Manufacturers of Turbine-Type, Vertical and Horizontal Centrifugal and Special Design Pumps Distributor* in Principal Cities Barring Unusual Conditions . We . MAINTAIN A COMPLETE Apco Single Stage Turbine-Type Pumps. Also available in Two Stage. STOCK FOR IMMEDIATE SHIPMENT Packaged Duplex Condensation Re turn Unit with No. 4 Series Apco Pumps; designed for smaller jobs. LARGER UNITS up to ISO gpm capacity, horizontal and vertical also available. APCO PUMPS are IDEALLY SUITED to MANY HEATING and AIR CONDI TIONING DUTIES--CAPACITIES UP TO 150 GPM--HEADS TO 600 FT. FEATURES--APCO pumps are distin guished for their ability to deliver small capacities against high heads; their abil ity to deliver with but slight change in capacity or efficiency against drastic head variations. They possess these advanced features--SIMPLE--WEAR-FREE-- COMPACT . HIGH EFFICIENCY . WILL NOT VAPOR BIND HYDRAULI CALLY BALANCED ACCESSIBIL ITY . HIGH SUCTION LIFT (28 ft at sea level) QUIET OPERATION . HIGH PRESSURE PER STAGE DOUBLE SUCTION DESIGN . PRECISION SHAFTS . BALL BEARINGS (support on both sides of impeller) RIGHT OR LEFT HAND OPERATION (Changeable in Field without special parts) RE PLACEABLE COVER PLATES AVAIL ABLE IN VARIOUS CORROSION RE SISTANT ALLOYS. LOW HEAD SMALL CAPACITY--SIDE SUCTION PUMPS At Left TYPE--SAC--Close Cou pled Caps 6 to 86 gpm. Heads to 15 Ft. Sizes Available lM", 2" MEDIUM HEAD At Right TYPE--JMC--Close Cou pled Caps, 6 to ISO gpm. Heads to 100 Ft. 'Sizes Available 1m, /H', APPLICATIONS SHAFTS--Stainless steel on Types JMC, Well suited as integral part of manufac SAC and JA. Can be furnished on turer's product such as air conditioning Type SA at additional cost. units, cooling towers, evaporator coolers, MOTOR Built to NEMA specifications hot water circulators etc., also for gen and equipped with STAINLESS STEEL eral service. CONSTRUCTION SPECIFICATIONS Made in bronze fitted, all iron or all bronze construction. CASINGS, vertically split--end suction. High grade material as specified. Cas ing wearing ring is standard on Type JMC. MECHANICAL SEAL is standard on all shaft. BALL BEARINGS--Permanently sealed against dust and moisture--No lubrica tion required. AURORA CENTRIFUGAL PUMPS ^ are available in many types and sizes all noted for their streamline co-ordina tion between impellers and shells. sizes and is located in packing cover-- easily replaceable. Write for IMPELLER is balanced, enclosed type of high grade bronze material. CONDENSED CATALOG "V" 1522 Heating Systems Pumps Buffalo Pumps, Inc. 450 Broadway, Buffalo, N. Y* Manufacturers of a complete line of Centrifugal Pumps, Single and Double Suction, Single and Multistage, for All Types of Heating and Air Conditioning Installations. Write For Engineering Bulletins on Your Problem or Consult Your Nearest Engineer ing Representative Listed Below: SALES REPRESENTATIVE LIST ALBAN Y N. Y., R. B. Taylor, 966 Broadway; ALBUQUERQUE, N. M., H. A. Munn, 730 Haines Ave N. W.; ATLANTA.GA..J.J. O'Shea, 305 Techwood Dr., N. Vi.;BALTIMORE 1, MD., Machinery & Equip ment Sales, Inc., 1014 Cathedral St.; BIRMINGHAM, ALA., J. H. Judd, Room 2226 Comer BldgBOSTON 76, MASS..R. D. Johnson, 507 Main St., Melrose Station; CHICAGO 6, ILL., Trurabo, Johnson and Heckel 20 N. Wacker Dr.; CINCINNATI 9;OHIO,i. W. Gibbs, 3047 Madison Rd.; CLEVELAND 16, OHIO, Sher man & Weager, 570 Hanna Bldg.; CORPUS CHRISTI, TEX., Langhammer Rummel Co , 101 North Ala meda St.; DALLAS, TEX., T. H. Anspacher, 615 Tower Petroleum Bldg.; DA VENPORT IOWA, D. C Murphy Co., 305 Security Bldg.; DENVER IT, COLO., Stearns-Roger Mfg. Co., 1716 California St.; DBS MOINES 14, IOWA. D. C. Murphy Company, 840 Fifth Ave.; DETROIT 16, MICH., Coon-DeVieser Co 2051 W. Lafayette Blvd.; EL PASO, TEX., Stearns-Roger Mfg. Co., P. O. Box 38; GREENVILLE. S. C Roy A. Stipp, P. O. Box 1796,104 E. Stone Ave.; HOUSTON C, TEX., D. M. Robinson, 2436 South Blvd INDIANAPOLIS 4, IND., S. E. Fenstermaker & Co., 937 Architects & Builders' Bl^g. JACKSONVILLE 4, FLA., H. L. McMurry Co., 25 Riverside Viaduct; KANSAS CITY 6, MO , W. K. Dyer, Post Office Bldg Mission, Kansas; LITTLE ROCK, ARK., J. L. Brown, 212 Terminal Warehouse Bldg.; LOS ANGELES IS CALIF., Halladay & Knauff, 804 Pershing Sq. Bldg.; LOUISVILLE 2, KY., H. M. Lutes, 633 So. Fifth St MEMPHIS 6, TENN., C. J. Gaskell Co., 216 N. Lauderdale Ave.; MIAMI Si, FLA., H. L McMurry <fcCo 46 N. E. Sixth St.; MINNEAPOLIS 2, MINN., E. F. Bel1, 2102 Foehay Tower; NEWARK 2, N. J., Johnson A Norman, 27 Washington St., Room 205; NEW ORLEANS 12, LA., Devlin Bros., 1003 Maritime Bldg NEW YORK 17, N. Y., Johnson & Norman, 41 E. 42nd St.; OMAHA 2, NEB., Wain Engineering Co., 2311 Douglas St.; PHILADELPHIA 2, PA., Davidson & Hunger, 220 S. 16th St.; PHOENIX, ARIZ., J. E. Redmond Supply Co., 625 W. Madison St.; PITTSBURGH 22, PENN., H. Lee Moore, 345 Fourth Ave PORTLAND, ME., Ruel E. Taylor, Jr., and Harold E. Ingalls, 25 Commercial St.; PORTLAND 6, ORE ' Arthur Forsyth Co.. 921 S. W. Oak St.; ROCHESTER 4, N. Y., R. D. Moyer, 532 Sibley Tower Bldig.; ST LOUIS 9, MO..J. W. Cooper, 3805 Washington St.; SALT LAKE CITY 1, UTAH, Stearns-Roger Mfg. Co 40 Richards St.; SAN ANTONIO 6, TEX., Langhammer Rummel Co., 300 Blum St., P. O Box 367; SAN FRANCISCOS, CALIF., Richard Stites, 1214 Central Tower Bldg.; SEATTLE 99, WASH., A. T. Foreyth Co., 2800 15th Ave. West; SPOKANE 8, WASH., A. T. Forsyth Co., 601 Hyde Bldg.; TOLEDO 2, OHIO. C. M. Eyster Co., 1118 Madison Ave.; WASHINGTON 6, D. C., G. S. Frankel, 310 Woodward Bldg. SINGLE STAGE DOUBLE SUCTION PUMPS. For clear water service from 10 to 10,000 gpm, and for heads up to 350 feet, these efficient pumps are widely used for air washers and other air condi tioning units. Each pump is hydrauli cally balanced (water enters each side of impeller with equal pressure and vol ume), which contributes to the smooth operation and efficiency, as do simply formed water passages in the casing. BULLETIN 955-P. AUTOMATIC SUMP PUMPS. Compact units, shipped complete, ready for quick installation. Ball bearing thrust carries weight of moving parts. Shaft is entirely enclosed--completely protected from sump water and from fouling with waste or stringy matter flowing into sump pit. All parts are readily accessible. BUL LETIN 963-G. CLOSE-COUPLED SINGLE SUCTION PUMPS. Extremely compact design per mits installation vertically or horizon tally. Available with either threaded or flanged connections. Suited to handling hot water with low submergence. Im peller overhung on motor shaft assures permanent alignment. BULLETIN 975-C SINGLE SUCTION MULTISTAGE PUMPS. For handling clear water at high pressures, any temperature, are widely used for boiler feed service. Avail able in two and four stage models for capacities from 20 gpm to 900 gpm at pressures up to 1500 ft beads. Write for BULLETIN 980-C. 1523 Heating Systems Pumps Chicago Pump Company 622 W. Diversey Parkway EAstgate 7-102&-- Chicago 14 PRODUCTS--Return Line Vacuum Heating and Boiler Feed Pumps, Condensation, House, Booster, Fire Pumps, Circulating, Brine, Sewage, Bilge, Sludge, Pneu matic and Tankless Water Supply Systems and Automatic Alternator for Duplex Sets of Pumps. Fig. I) 9500--Duplex "Condo-Vacs" toith Duplex Double Automatic Control "CONDO-VAC" Return Line Vacuum and Boiler Feed Pump for Heating Systems No vacuum on stuffing boxes, ample clearance in rotating member. It costs less to operate a "Condo-Vac." "CondoVac" reduces corrosion in piping and boiler to minimum--because pump does not take in air from atmosphere and en tirely eliminates all air coming back from system. "Condo-Vac" is quiet, has a low inlet, entirely automatic, fool-proof, easy to maintain. Ask for Bulletin 270. For every heating system get the pump that is specifically designed for the par ticular job. For below floor returns, for low vacuum systems, for small capacity high pressure requirements, for any standard heating system, or any unusual condition, there is a CHICAGO Heating Pump that will do the job better. "SURE-RETURN" CONDENSATION PUMPS for Low and Medium Pressure, and Sys tems up to 75,000 Sq Ft Radiation "Sure-Return''Condensation Pumps and Receivers are built for systems up to 75,000 sq ft of direct radiation and for low and medium pressures. Built in either single or duplex units. Duplex units are alternated in their operation by the Automatic Alternator. Complete data in Bulletin 260. . Fig. D-SttOO . VERTICAL CONDENSATION PUMPS for Low and Medium Pressure for Sys tems from 500 to 100,000 Sq Ft Radiation The vertical condensation pump is designed to receive re turns from lowest radiation. The receiver is placed under ground--an ordinary hole sufficing if necessary--and requires very little floor space. Unit is shipped complete, easy to install, assembled so as to prevent steam leaks. Special bearings will stand up under hot water for several years. A special float mechanism is guaranteed not to leak or stick in stuffing box. Complete data and description in Bulletins 246, 26S and 26S. 1524 Heating Systems Pomps Chicago Pump Company 622 W. Diversey Parkway EAstgate 7-1020 Chicago 14 PRODUCTS--Return Line Vacuum Heating and Boiler Feed Pumps, Condensation, House, Booster, Fire Pumps, Circulating, Brine, Sewage, Bilge, Sludge, Pneu matic and Tankless Water Supply Systems and Automatic Alternator for Duplex Sets of Pumps. TYPE D, DOUBLE SUCTION, HORI ZONTALLY SPLIT CASE PUMP For house pump, fire and booster service. A ruggedly built, heavy duty pump for long trouble-free service. The rotating assembly may be inspected without dis connecting the piping. Capacities up to 1900 gpm--heads to 530 ft. Described in Bulletin 101. Type D, Double Suction, Horizontally Split Case Pump For circulating service, heating, bilge, or sewage pumping, CHICAGO equipment is among the best available. Each pump is specifically designed to do the particu lar job and do it right. Over 40 yeare ex perience with pumps for every applica tion is built into every unit. For "worry proof" pumping at all times--specify CHICAGO Industrial Pumps. TYPE C-C, CLOSE COUPLED BOOSTER PUMP Designed to handle the toughest pump ing jobs efficiently and in the least pos sible space. May be mounted in any po sition as long as the motor is not lower than the pump. Provided with leak proof mechanical seal. Capacities up to 500 gpm--heads to 215 ft. Described in Bulletin 108. Type C-C, Close Coupled Booster Pump TYPE F-C, PEDESTAL MOUNTED, SIDE SUCTION PUMP Built to the same exacting engineering standards as the Type C-C Pump and with the same capacity and head. The flexible coupling drive permits easy field servicing and the use of customer's choice of motor manufacture. Described in Bulletin 107. . Type F-C, Pedestal Mounted, Side Suction Pump M m m. m l;U- Heating Systems * ptmps Decatur Pump Company 2750 Nelson Park Road Decatur, Illinois Distributors in Principal Cities .. PUMPS BURKS SUPER TURBINE PUMPSSeries C---a complete line of pumps, self priming, fully automatic, with patented "Life-Lok" feature. Ideal for circulat ing, booster and other applications. Ca pacities to 1520 gph, pressures to 100 psi. BURKS SUPER TURBINE PUMPS-- Series E--a line of independent pumping units available with or without motors. Adapted for condensation return units, circulating systems, booster service and water systems. Capacities to 2120 gph, pressures to 150 psi. Super Turbine Series C Super Turbine Series E CONDENSATION RETURN AND BOILER FEED UNITS--Complete line, factory assembled, equipped with Burks Super Turbine pump and tank. Will not steam bind. A 3 to 1 safety factor pro vides ample reserve for peak loads. a Sizes: J4 to 1 hp serving up to 124 hp j| boiler or 16,500 sq ft radiation. Pressures 9 to 100 psi. * CENTRIFUGAL PUMPS--Series IHVr designed for booster, circulating and air conditioning applications. Equipped with control valve for adjusting to most efficient pressure. May be installed hori zontally or vertically. Patented "KamAction" impeller design with straight line volute. Capacities to 110 gpm, heads to 190 ft. Also available in Series HV for use with educers for deep wells to 210 ft. Condensation Return and Boiler Feed Units BURKS WATER SYSTEMS--Factory assembled complete with Burks Super Turbine pump and 20-gal tank. For shal low wells, capacities to 590 gph. Other shallow and deep well systems available not factory assembled with capacities to 1520 gph. Complete catalogs available on request Centrifugal Series J H V' Turbine Water Systems 1526 ATLANTA BIRMINGHAM BOSTON BUFFALO BUTTE CHICAGO CINCINNATI CLEVELAND DALLAS Heating Systems Pumps Ingenyoll-Rand II BROADWAY. NEW YORK 4. N. Y. DENVER DETROIT DULUTH EL PASO HOUSTON IfAURAS PITT KNOXVILLE LMOINSNAENAGPEOLLEISS NEWARK NEW ORLEANS NEW YORK PHILADELPHIA FICHEB fTTTSBUHQH Offices and agents throughout the world POTTSVILLB BALT LAKE CITY SAN FRANCISCO 8CRANTON SEATTLE BT. LOUIS TULSA WASHINGTON WILMINGTON CENTRIFUGAL PUMPS The K2W2)(j^|F)0!)lBP ;s a compact, "pack age" unit, mounted integrally with motor on a rigid, oversize shaft and over-size bearings- it is highly adaptable to many services, needs no special foundations, and operates equally well in any position. It js available in several materials for pump ing various liquids. Capacities from 10 to 1800 gpm, heads to 650 ft. Other I-R pumps are offered for all hy draulic services, with any type of drive ALL PURPOSE PORTABLE TOOLS Electric Impactools are light-weight, portable, tools for running and removing nuts, screws and studs, drilling, reaming, tapping, wire brushing, drilling brick ana masonry, driving wood augers, holesaw work, and the 101 jobs encounte red in installation work. Plug into any wall outlet. Capacities: % in. drills, tapping to % in., running nuts to % in. thread size. 110 or 220 volts, universal motor. STEAM-JET REFRIGERATION Where refrigeration is needed down to 35F, and a supply of steam is available, the I-R system of Stream-Jet WaterVapor Refrigeration should be consid ered. In this system water is the only refrigeration medium. It is cooled by direct evaporation in a high vacuum created by steam-jet booster ejectors. There are no moving parts, no vibration, nor noise. Sizes run from 30 to 1000 tons of refrigeration and can be built to oper ate at any one of a wide ran^e of steam pressures down to 1 lb per sq in. LIGHT-WEIGHT JACKHAMER The J-10 Jackbamer is the smallest of the self-rotating, rock-drill line, weighs 14 lbs, and is especially designed for mainte nance and installation work. Its uses include drilling masonry for conduit, sprinkler hangers, foundation bolt holes, pipe lines and drains as well as tearing out brick-work for doors and windows and similar demolition jobs. The J-10 is air-powered. I-R COMPRESSORS OF ALL TYPES AND SIZES I-R Compressors are offered in all sizes and types from `/i to 3000 hp, in pressures from a few ounces to 15000 psi, and in stationary or portable models. Air-cooled Units range from '/t to 100 hp. I-R Water systems are available for industrial and domestic uses. 1527 Heating Systems Pomw The Nash Engineering Company 234 Wilson Road South Norwalk, Conn., U. S. A. Sales and Service Offices in all Principal Cities Heating Systems * famp* 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 anti efficiency. Complete flexibility is secured in this design, since each pumping element is driven byTihtsisomwankmesoptoors,saibclteuaatewdidbeyraitnsgoewonf caoirnatrnodl. water capacities that can be selected toTmheeseet tphuemepxsacatrerenqouwireamvaeinlatsbleofineaachfupllarratincguelaorfjoabir.and water capacity combina tions, for operation up to 20 inches Hg vacuum, and for pressures from 10 lbs to 70 lbs. Bulletin on request. JENNINGS VAPOR TURBINE VACUUM HEATING PUMPS The Vapor Turbine combines all the advantages o! our standard return line heat ing pumps with a new type of drive, a specially designed low pressure turbine which operates on any system, on steam directly from the heating mains, eliminating elec tric motor. Requires a differential of only 5 in. of mercury, and returns steam used to the heating system immediately, with little heat loss- This pump affords the ^safety and economy which goes with a continuous condensation return and steady * vacuum, and at no cost for electric current. Up to 150,000 sq ft equivalent direct radiation. Larger sizes built special. Bulletin on request. RETURN LINE VACUUM HEATING PUMP Bemoves air and condensation fUroNmITreTtYuPrnE lines of vacuum heating systems. Separation of liquid and gas is made under vacuum. Independent air and water units, combined in single casing and rotating on single shaft, handle returns with high efficiency. Air unit delivers to atmosphere without back pressure. Water unit delivers directly to boiler. Bronze fitted throughout. No internal wearing parts. No internal lubrication. Supplied direct connected to electric motor, or for belt drive, for continuous operation or with automatic control. Standard capaci ties up to 40,000 sq ft equivalent direct radiation. Larger units special. Bulletin on request. 1528 CONDENSATION PUMP Removes the condensation from radiators in return line steam heating systems, particularly radiators set below the boiler water line level, and pumps the condensa tion back to the boiler. Tump is bronze fitted with enclosed centrifugal impeller of improved design. By making the pump casing a part of the return tank, and bolting the motor base to the tank, floor space is conserved. The rectangular con struction permits installation in a corner against the wall.^ Supplied in standard sizes with capacities ranging from V/$ to 225 gpm of water. Por serving up to 150,000 sq ft of equivalent direct radiation. Bulletin on request. . 1529 . Heating System Pumps 297 Williams Ave. Hackensack, N.J. . Sales representatives in principal cities. Pumps and separators for fuel oil burner and heating service; circulators for water service; filters and strainers for oil, water, liquids, air and steam applications. Class 50 Light Oil Pumps Direct drive for No. 1 to No. 4 oils in clusive. High suction lift; pressures up to 100 psi. Ask for bulletin A-1SS0. Particularly adapted to dirty oil condi ; tions where extraneous matter would cause seizure in more closely fitted mech anisms. Capacity 1 to 10 gpm. Class 60 M Pumps provide capacities from 2 to 212 gpm; special bearings available for solvent service. Class 60 Heavy Oil Pumps Reduction drive for heavy oils including No. 6 and blended No. 5--for direct burner operation or booster pump appli cation. Internal gear type, machined to close tolerances for max. vacuum characteristics. Ball bearing, V-belt reduction drive-connected to pump by loose coupling--eliminate side deflection from pump shaft. Suction and discharge in. to 2 in.; capacities 75 to 2100 gph; pressures to 100 psi. Write for bulletin A-1198 Class 72 Separators Strainers or filters for both suction and discharge service on every burner instal lation. Single and duplex units for both standard and high pressure service. De sign features ease of cleaning and inter changeability of separator baskets. Available with Underwriters Labels.from in. to 4 in.; larger sizes up to 6 in. Ask for bulletin A-14S0 UL listed single strainers for installation as integral part of pump type burners. Any practical degree of separation; sizes H in. to 4 in. inclusive. Ask for bulletin A-liH Class 34 Water Circulators Enclosed-impeller type centrifugal pump for both vertical and horizontal mount- ings--particularly suitable for high head L applications. Ball bearing construction , . mreopluancteinabgleanwderaermpoluanteti,ngsiwmipthliofiuedt1c5od3mis0- . plete disassembly. Capacities up to 140 gpm. Ask for bulletin A-1SS1 Heating Systems * Pumps Peerless Pump Division Food Machinery and Chemical Corporation PLANTS: Los Angeles 31, CaliL, Indianapolis 8. lad. PRODUCTS: Offices: New York; Atlanta; Indianapolis; Chicago; SL Louis; Tulsa; Dallas. Plainview, Lubbock. Texas; Albuquerque. New Mexico; Phoe nix, Arizona; Fresno. Los Angeles. Calif. 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. Seals: Mechanical shaft seals for rotative shaft equipment and pumps. From \ in. to 5 in. in diameter. Peerless Type PE and Type PB general purpose, end-suction close and flexible coupled pumps (at left). One of the most complete lines offered by any manufacturer. Capacities: to 5500 gpm. Sizes: ^-150 hp. Heads: up to 260 feet. Single stage design. Compact, versatile, dependable and efficient. Good hydraulic character istics. Completely described in Bul letin B-2800. Peerless Type AS general purpose horizontal split case pump equipped with me chanical shaft seals (at right). A packingless pump almost one half the size of conventional pumps offering same capacities and pressures. Saves space. Short shaft lengthens life. Smooth operation. Sizes: in. x 8H inthrough 4 in. x 13 in. Capacities: up to 750 gpm. Heads: to 230 feet; tempera tures to 200 F. All types of drive. Completely described in Bulletin B-1850. Also larger size, designated as type "A/* to 48 in. discharge for higher heads and capacities. Completely described in Bulletin B-1800. Peerless Type TVE and TVB turbine vane type pumps for high temperatures and high heads (at left). Standard and self-priming pumps for boosting, circulating and boiler feed application. Handle cold or hot water to 250 F. Heads: up to 800 feet. Ca pacities: up to 58 gpm. Sizes: Frac tional to 20 hp. Compact, dependable, modern design. Completely described in Bulletin B-2205. Peerless Underwriters* Approved Hori zontal Fire Pumps (at right). The standard of the fire protection in dustry. Famous Dayton-Dowd design. Electric, engine or steam turbine drive. Capacities: 500 to 2000 gpm. All re quired heads. Request Bulletin B-1S00. OTHER PEERLESS BULLETINS are available; completely describing each type of pump in the Peerless line. Request copies describing tne type pump in which you are interested. * 1531 Heating Systems Pumps Skidmore Corporation St. Joseph, Michigan Quality Heating Pumps for over a quarter of a century Write for Bulletin No. 19-A on Type W Pump , Bulletin No. tl-A on Type CV Pump\ j SKIDMORE TYPE UV PUMP The Skidmore Type UV Condensation Pump, single or duplex unit, is designed for me 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 mechanism mounted on cover plate which is bolted to sump type receiver. Capacities 2000 to 40,000 sq ft EDR and discharge pres sures from 10 to 75 lbs. SKIDMORE TYPE CV PUMP The Skidmore Type CV Condensate Pump is built for maximum efficiency and requires a minimum of space. De signed in both single and duplex units. Shown above is the duplex pump with two float switches. This model can also be furnished with automatic alter nator on all sizes. Integral pump casing and motor stand are of cast iron construction, bolted to top of receiver. Pump is bronze fitted throughout, with enclosed centrifugal impeller of special design for hot water. Capacities 500 to 10,000 sq ft EDR, pressures from 10 to 20 lbs. Write for Bulletin No. J4-A on Type HS Pump Bulletin No. 17 on Type TM Pump SKIDMORE TYPE HS PUMP SKIDMORE TYPE TM PUMP Type TM pump consists of motor, The model HS Condensation pump is steel receiver, automatic make-up valve economically designed to offer maximum mounted on receiver, water level gage efficiency with lower operating cost. The Type HS will operate at high glass mounted on receiver, self-cleaniDg strainer between pump and receiver, temperature encountered in condensa assembled and mounted on steel base. tion pump service. The pump can be Cast iron base furnished if required. disassembled without disturbing piping Electric boiler water level controller connections. Furnished in either single or duplex type. Pump casing is con furnished for mounting on boiler. The Type TM Condensate and make structed of heavy close grain cast iron, up water pump is of turbine type de vertically split, bronze fitted throughout. Capacities 1,000 to 65,000 sq ft EDR, pressures .1r0t t.o. -7re5 ulb--s. signed for boilers up to 250 hp and pres sures up to 150 lbs. Write for Complete Engineering Data Bulletins on Skidmore Gondensate and Vacuum Pumps will be sent on request, 1532 Heating Systems Pumps C. H. Wheeler Manufacturing Co. Economy Pumps Division 19th & Lehigh, Philadelphia 32, Pa. For name of nearesTdistritrator, check 50111 phone directory or write to factory in Philadelphia WHEELER-ECONOMY HOT WATER CIRCULATING PUMPS Type SCV--Vertical direct connected TypeSCC--Close coupled vertical or horcentrifugal. 1 in. to 3 in. Up to 500 izontal mounted. 1)$ in. and 2 in. Up gpm. 1150 to 3450 rpm. Heads to 225 ft. to 100 gpm. 3450 rpm. Heads to 120 ft. WHEELER-ECONOMY VACUUM PUMPS Type W--Vertical. For operating be tween 3 and 12 inches vacuum. Dis charge pressures to 150 lb. sq in. EDR 2500 to 15,000 sq ft. Single and duplex units. Also available in Special Ca pacities. Type SVA--Horizontal. For operating between 3 and 12 inches vacuum. Dis charge pressures to 150 lb sq in. EDR 20,000 to 100,000 sq ft. Single and du plex units. Also available in Special Capacities. WHEELER-ECONOMY RETURN CONDENSATION PUMPS Type E--1750 rpm. (1450 rpm at 50 cycle current). Quiet operation. Single and duplex units. Direct C.I. radiation or equivalent: 1000 to 65,000 sq ft. Type MR--Lightweight Pump for low pressure steam heating systems. Ca pacities to 65,000 sq ft. EDR. Single and Duplex Units. Type EC--For same or higher pressure than Type E. 3450 rpm. (2880 rpm for 50 cycle current). Direct C.I. radiation or equivalent 1000 to 65,000 sq ft. Single and duplex units. Type B--Horizontal Return Condensa tion Pump--multi-stage type for press ures to 150 lbs. 1750 rpm. Quiet opera tion. Direct C.I. radiation or equivalent, Type U--Vertical Underground. For re turns below floor level, etc. No pit re quired for pump. Dow and medium pressure units equipped with single stage pumps of vertical design. For higher pressure units a multi-stage pump of special design is used. Direct C.I. radiation or equivalent 2000 to 50,000 6000 to 65,000 sq ft. Type C multi-stage for pressures to 175 lbs 3600 rpm 60 cycle. Identical to Type B except for higher speed operation. , Type G--Horizontal Return Condensa tion Pump--Single suction, single stage for medium and high pressures. 1800 to sq ft. Single and duplex units. 3450 rpm. Type SCV . Type VV Types E & EC 1533 Type V Types B & C Heating Systems Specialties The V. D. Anderson Company I960 West 96th Street, Cleveland, Ohio-.. ' Quality Steam Specialties Since 1886 Representatives in all principal cities SUPER SILVERTOP STEAM TRAPS Inverted bucket steam traps of ah improved, thoroughly tested design. For use on steam-iising equipment where it is desired to remove condensate and air automatically in order to produce maximum heating efficiency. These . steam traps automatically remove both condensate and air--no manual opera tions are necessary. FEATURES Simplified Piping--Hooks up as an elbow or straight-in-line--only one nipple needed since the U-tube is inside the trap. Saves 3 elbows, 3 nipples and 60 minutes of time, compared to conven tional inverted bucket steam traps. Precision Parts Alignment--The bucket does not swing free. It is controlled in true engineering fashion, guided on a hexagonal tube. This makes a knifeedge contact, eliminating almost all friction. The unusual guide arrangement keeps all parts in proper alignment and prevents the bucket from hitting the sidewalls of the case. Positive closing of the valve is insured. Self-Cleaning--The reversing of the condensate flow on entering the trap produces a scrubbing action. This stirs up any sediment and dirt which is car ried away in the discharging condensate. No Restricting Passages--Even in the smallest sizes there are no narrow cored passages to become clogged with scale. Cannot Air-Bind--As the air is auto matically discharged ahead of the condensate in each cycle of operation. me Vacuum or Pressure--These traps do not leak steam. No danger of vacuum being destroyed--trap is recommended for vacuum operation. THREE TYPES OF STEAM TRAPS Standard Inverted Bucket--Use where normal heat-up periods are satisfactory. Thermal Air Eliminator--This trap should always be used where instant heat is necessary. Combination--Designed for extremely fast air elimination at pressures up to 150 psi. 5ize No. Trap.......... lire Connections---- (See Note) 4ax. Ga. Pressure... jist Price.. ........... - ns .tf' or W ISO $9.00 119 H'm or Y* 200 $10.00 120 Vi" or W 200 $12.00 121 Vi' or 44' 200 $16.00 122 H' or 1' 250 $25.00 25 tyf or r 250 $70.00 list Price.. . WITH THERMAL AIR ELIMINATOR [ $11.60 | $10.60^1 $11.60 1 $13.60 \ $17.60 ) $28.20 \ $35.20 \ $49^8 Inferential CAPACITY IN POUNDS OF WATER PER HOUR Teesure 137 305 435 300 455 440 250/ ... 161 360 505 700 650 455 500 450 } ... 225 510 705 930 900 675 740 580 655 i ... i 390 970 1190 1650 1400 1200 1310 1000 1100 .... i 790 1790 2480 3450 2490 2380 2060 2220 1920 .... 1220 2720 3850 3980 4180 3740 4090 4400 3700 3600 , 1500 3200 4600 6000 4500 4200 3400 3700 4150 4__5_00 2400 5274 7500 11100 7500 1000C 8900 .. 9200 21000 29650 40300 26000 25300 19100 20500 16800 13750 Capacities based on continuous flow. When ordering be sure to specify maximum steam pressure. ipe sizes shown in heavy type are standard and traps will be shipped tapped standard unless other" >ecified. Pipe sizes shown in light type furnished at no additional cost but only from Cleveland stock* 1534 . The V. D. Anderson Co. Heating Systems Specialties Size No. Trap 119BL 119BH Size Conn... . 44' K* Max. Gage... 50 150. List Price.... $16.00 22.00 120BL 50 18.00 COMBINATION TRAPS 120BH 121BL 121BH 122BL 44' ys W 1' 150 24.00 220C 28.00 50 31.00 122BH 150 37.00 23BL 23BH 1' 1* 50 150 38.00 44.00 24BL 24BR W IH* 50 150 54.00 60.00 PRESS. 3 5 10 15 20 30 50 SO 100 125 150 4S7 880 1136 1584 1890 2108 2166 2731 487 880 1136 1584 1890 2108 2166 2731 3109 3143 3447 3484 CAPACITY IN POUNDS OF WATER PER HOUR 652 1158 1596 2069 2458 2858 2566 3231 652 1158 1596 2069 2458 < 2858 2566 3231 3569 3668 4017 3904 1C52 1868 2416 3359 3988 4658 4026 4321 1052 1868 2416 3359 3988 4658 4026 4321 4419 4848 . 4767 5124 1482 2598 3346 4729 5158 5188 6256 6011 1482 2598 3346 4729 5158 5188 6256 6011 6549 6208 6797 7304 1762 2988 3826 5479 6458 7208 5956 6331 1762 2988 3826 5479 6458 7208 5956 6331 5999 6668 6107 6604 2662 4588 5900 8379 11058 12308 7656 9331 2662 4588 5900 8379 11058 12308 7656 9331 10849 12468 10707 11504 Capacities based on continuous flow. When ordering be sure to specify maximum steam pressure. Anderson Air Release Valves Anderson Air Release Valve No 171 Anderson air release valves are automatic air vents used for venting air from hot water service and heating systems. Eliminates the annoying venting of air through faucets when water is first turned on. The air release valve consists of an extremely durable valve and seat, a fool-proof lever and ball float which opens or closes the valve, depending upon the presence of water or air. Write for Bulletin No. 4^4- Anderson Hi-eF Purifiers are used on steam lines and in boilers to produce clean, dry steam. Type L shown here should always be used ahead of steam engines and turbines to protect this valuable equipment against slugs, line scale, moisture, salts and dirt. Internal type Hi-eF Purifiers should be installed in boilers to assure the delivery of clean, dry steam devoid of carryover, entrain ment and condensate. Also for use in cleaning and drying air and other gases. Write for Bulletin No. 700. - Hi-eF Purifiers Anderson Hi-eF Purifier Type L > - Anderson Strainers / J Anderson Self-CleaniDg Strainers remove scale, grit, and sedi: - [ ment from the line ahead of steam traps, reducing valves, air ' tools, pumps, temperature regulators, etc. Stainless steel 1 strainer screens (brass available on in. and 3 in.) are stand- *4 ard equipment and have an extremely large free area. Standard j screen for steam and other gases has in. openings;--for i liquids H2 in. openings. Other sizes of openings furnished ^ when specified, prices on application. Pipe Size.......................................... Overall Length.............................. Blowdown Connection Pipe Size Shipping Weight (lbs.)................ List Price..... ....................................... (Stainless Steel Screen) List Price.............................................. (Brass Screen) SPECIFICATIONS AND PRICES V4' 3V4' Vi' 1 $2.00 W 3 Vi* h* 1 $2.50 V** 3M* w m $2.75 44' 44' 2 Vi $3.25 1* 44i' 344 $4.00 1W' 5H' r svi $5.00 6H' i' 2* 744' 2 Vi' 844' 3' 10* . Hi' 1V4' W m' 9V4 16V4 26 Vi . 40 * $7.25 $11.CO $28.00 $36.00 $22.00 $27.00 AS Heating Systems specialties Armstrong Machine Works 851 Maple Street, Three Rivers, Mich. Representatives in principal Centers Steam Traps... Air and Air Relief Traps... IIOlCOStieUam HUlutumwitdwiufivearsV .. .. ..Refrigerant Puig_ers All Armstrong Products are Sold on a Basis of Satisfaction or Your Money Back Traps Stocked by 39 Factory Representatives and 135 Jobbers; Available Through Anv Tobber. , ARMSTRONG INVERTED BUCKET STEAM TRAPS APPLICATIONS. Armstrong manufac tures inverted bucket steam traps for any pressure from 0 to 2400 psig; for dis charging to high pressure, gravity or vacuum returns; for draining mains, risers, coils, heaters, radiators, unit heat ers and process equipment. FEATURES. High Quality Mechanisms in Armstrong traps for low and medium pressures are identical in design, work manship and materials to those used in traps for 950 psi, 900F. from 500 to 1500 cu ft free air per hour when steam is first turned on. High Capacity for Size. The patented free-floating lever mechanism makes pos sible wide opening of discharge orifices large for overall trap size and price. Arm strong capacity ratings, based on actual tests with hot condensate, are entirely reliable. Automatic Air Discharge. Standard traps discharge normal amounts of air along with condensate. "Blast" traps with thermic bucket vents discharge at rates . Tar ' No. 800-8H i----- t-r---- No. 880-881 Side Inlet Traps Pipe Connections List Price (Regular)___ List Price (Blast Trap) Telegraph Code (Regular) Telegraph Code (Blast Trap) Height Diameter .................. Number of Bolts... Diameter of Bolts Wright . Maximum Pressure, lbs. Continuous dis~ charge capacity in lb of water per hour at pressure indi cated. For more complete informa tion see the Capa city Chart in Arm strong Steam Trap Book. Rnttnm Inlet Traps Pipe Connections List Price (Regular) . List Price (Blast Trap) Telegraph Code (Regular). Telegraph Code (Blast Trap) Height... Diameter Diameter of Bolts Number of Bolts Weight--.................. .. Minimum Pressure, lb-- 1536 Armstrong Machine Works Heating Systems spedamw Non-clogging. Swirling action of conden sate carries dirt through trap. The larger sizes seldom require the extra cost of strainer protection. Quick-Acting. Condensate and air are discharged as fast as they reach the trap, providing fast heatup and maximum temperatures. CHOICE OF BODY STYLES. In the roost commonly used sizes, Armstrong traps are available in several body styles to simplify, and reduce the cost of, in stallation. Side Inlet Series. Traps number 800,811, 812, 813, 814 have horizontal and oppo site pipe connections. Capacities and mechanisms of 811, 812, 813, 814 are identical to bottom inlet traps 211, 212, 213, 214. Integral Strainer Models. No. 880 and 881 traps have strainers in the trap body; otherwise identical to 800 and 811 traps. No. 880 lists at $11.50, 881 at $16.00. Both cost less to buy and install than a trap plus separate strainer. Right Angle Trap. No. 801 capacity and price identical to No. 800 listed,in table. For replacing old radiator traps or wher ever angle connections are simplest. Bottom Inlet Traps. No. 211 through 216 have bottom inlet top outlet connections. TECHNICAL LITERATURE. (Avail able free upon request) Catalog J. The Armstrong Steam Trap Book. 44 pages of data on trap selection, installation, maintenance and trouble shooting for all classes of equipment. How to Select Traps for Draining Unit Heaters--lists the Btu Output Ratings for all sizes and types of 30 makes of unit heaters in a convenient single source. ARMSTRONG STEAM HUMIDIFIERS For Stores, Offices, Hospitals, Factories, Laboratories Operation. These units provide auto matic, closely controlled humidification ' by introduction of steam directly into the room. Installation is comparable to unit heaters. A solenoid discharge valve on the hu smallest unit, capable of humidifying up midifier is controlled by a sensitive hu- to 40,000 cu ft, lists at $182.25 complete midistat. A fan or venturi nozzle aids with control. No extra load on the heat steam dispersal. Where an electric spark ing system. No dripping--any moisture is an explosion hazard, air operated in the steam is re-evaporated in the models are available. A large model for steam - jacketed separating chamber. installation in air ducts and central heat Control is accurate within a few per cent ing systems is also made. Capacities R. H. range from 31 to 630 lbs/hr steam. Bulletin No. 1775 gives complete data on Advantages. Installation cost is as much required relative humidities, selection as 80 per cent less than some types. The and installation of Humidifiers. OTHER PRODUCTS (Bulletins free on Request) Bulletin 2062--Armstrong ball float traps for venting air from hot water systems. Bulletin 1921--Armstrong Purgers for discharging air, other non-condensable from refrigerating systems. Bulletin 241--Armstrong liquid seals.for refrigerating systems. 1537 / Heating Systems cabinets** jackets Atlas Manufacturing Company Eustis at Robbins St. Paul, Minnesota FURNACE CABINETS BOILER JACKETS Atlas furnace cabinets and boiler jackets are custom built to manufac turer's specifications. Furnished with or without full insulated panels or con ventional type baffles with air space. Atlas also produces cabinets for ventilat ing equipment, refrigeration cooling or evaporating cooling units. All Atlas cabinets are constructed from cold rolled steel sheets in gauges as per detailed drawings. Costs furnished on specifications or sample unit will be provided on order. Atlas "De Luxe" cabinets are con structed with full round corners and edges to produce a finished, pleasing ap pearance. Atlas "Quality" cabinets embody the nwio TOAplrmayioKin DA "De LllXe rounded top corners and edges, but square vertical corners on cabinet base and body. Atlas "Economy" cabinets are made with square corners and edges, but are identical in quality of workmanship with the higher priced styles. Allas "Economy" FINISH AND COLORS: Atlas cabinets and jackets are finished in oven baked hammerloid enamel, wrinkled or plain, in any selected color. Furnished complete with modern hardware. 1538 Heating Systems stem parties cJones New York Office: 101 Park Avenue 12S Brookside Avenue Boston 30, Mass. Barnes & Jones Vapor and Vacuum Systems of Steam Heating; Modulation Valves; Adjustable-Orifice Radiator Valves; Packless Quick-Opening Radiator Valves; Ther mostatic Radiator Traps; Thermostatic Trap Replacement Units; Condensators (Boiler Return Traps); Float and Thermostatic Traps; Strainers; Gages; Systems of Zone Control for Steam Heating. Complete Catalog on Request Vapor and Vacuum Series K--The Series K Valve is of the modulating type equipped with dial and pointer to indicate whether the valve is open or shut or in an intermediate position. Lever or wheel handle. Series F--The Series F Valve has no dial or pointer and is therefore furnished only with wheel handle or lock shield. Of same quality as Series K, but lower priced. Both Series K and Series F Valves are quick opening, have non-rising steins, renewable disc seats, of packless design. Made angle pattern in f, 1, and l in. sizes; straightway (globe) pattern in f and 1 in. sizes. For use in vapor or vacuum systems. Type H--The Type H Valve is of the adjustable orifice type so arranged that the dial indicates at all times the size of the radiator for which the valve is adjusted. May be adjusted with steam on the system. Noiseless in operation. Lever or wheel handle, unauthorized tampering virtually impossible. Made for pressure differentials of 1, 2,' 3, 4 and 5 pounds, f in. valve up to 100 sq ft. 1 in. valve over 100 sq ft. Thermostatic Radiator Traps--The B & J precision made ther mostatic trap contains the unique, patented cage unit which is a complete operating unit in itself. The cage assembly contains the double thermostatic element calibrated in the factory, and locked in correct adjustment with the trap seat, which is also an integral part of the cage unit. Suitable for pressures up to 15 lb J to 1 in. Medium and high pressure traps suitable for pressures between 15 lb and 100 lb can be furnished. Float and Thermostatic Traps--Barnes & Jones F&T traps respond instantly to sudden loads and pass condensate, regard less of temperature, through water sealed float operated valve. Thermostatic element gives rapid air venting. Made in Low and Medium pressure ratings. All working parts are readily accessible. No special wrenches needed. No disconnecting of pipe lines. { to 15 lbs pressure, f to 2 in. Cage Units--Most maintenance engineers believe in a regular check-up of their heating systems. Barnes and Jones make this check-up easy by providing a means for testing all steam traps, and for replacing the actuating units of any make trap. The B & J cape unit replaces all working parts. The double diaphragm unit is correctly and permanently adjusted before leaving the factory. Made for all sizes, pressures and makes of vapor and vacuum traps up to 65 lbs. It's a complete one-piece replacement containing thermostatic element, valve piece and seat locked in unalterable adjustment. No field calibration is necessary. Ask for Bulletins C-84 and R-1&. Temperature Controls--"Proportionator" is the trade name applied to Barnes & Jones continuous flow heating systems. Continuous flow of steam proportioned to the need. Continuous economy by using only as much steam as required and reduc ing the flow as the weather becomes milder. Continuous comfort because the radia tors at all times provide some heat so that the normal convection currents of air in a room are always active. There are no dead points. There is no "cold deg", which is experienced in the ordinary "on-and-off" system. B & J controls are available for both vacuum and vapor systems. Ask for the bulletins. 1539 I- Heating Systems specWtiM Carty & Moore Engineering Co. 1150 W, Baltimore Ave. Established 1914 ' _ Detroit 2, Mich. STEEL RADIATOR BRACKETS STEEL CONCRETE INSERTS For over a quarter of a century Carty-Moore Speed Brackets have been recognized by engineers and contractors as a superior product and there are nearly a million in use today. Specify C & M Brackets on your next job and note the substantial savings in labor due to the quick-mounting features. Model No. SS Bottom Bung Speed Radiator Brackets Model No. U Concrete Inserts Illustrated is the No. 22 Speed Bracket for-hanging all types of wall, tube or thin-tube radiation. This bracket is com pletely assembled when shipped and all parts are furnished, ready for quick and easy installation. A brief instruction card is enclosed with each bracket explaining the sinmle ad justments required to hang any particular type of radiation. Preparation of a C & M Speed Bracket for hanging a radiator consists simply of selecting the right hold-back washer (there are three furnished) and bolting the hook in the proper hole. Roughing-in specifications are shown by the drawing on the right. For specific jobs 30 brackets are packed to a burlap bag--jobbers Btock them Bix in an attractively-labeled carton. Shipping weight approx. 3i lbs. ,. Model No. 33--A completely assembled top hung bracset with 1J in. outset from the wall, especially approved for govern ment jobs. When ordering top hung brackets, specify model number and the type of radiation to be hung. - ' . Carty-Moore No. 44 Concrete Inserts have long been used by leading heating contractors and are designed to meet the most exacting requirements. The C & M Insert is made of heavy gage pressed steel stampings for I in., , >n > | in. and 1 in. nuts. A long travel slot permits ample adjustment yet the nut . cannot pull out and the wide wing- spread allows the insert to become deep y imbedded in the concrete so it cannot tear out under heavy strain. 50-1 in. or 1 Model No. SS Bottom Hung Brackets 4 in. packed in a nicely-labeled carton 25-f in. or i in. 1540 Heating Systems * C. A. Dunham Company HEATING SYSTEMS AND EQUIPMENT 400 W. Madison St., Chicago Toronto London Heating Systems Radiation , Unit Heaters Pumps Specialties Akron, Ohio Albuquerque, N. M. Allentown, Pa. Atlanta, Ga. Baltimore, Mb. Birmingham, Ala, Boston, Mass. Buffalo, N. Y. Champaign, Im>, Chicago, Iii,. Cincinnati, Ohio Clarksburg, W. Va. Cleveland, Ohio Columbus, Omo . Dallas, Tees. Davenport, Iowa Datton, Ohio Sales Engineers ii All Principal Cities Denver, Colo. Des Moines, Iowa Detroit, Mich. Duluth, Minn. El Paso, Tex. Grand Rapids, Mich. Greenville, S. C. Houston, Tex. Huntington, W. Va. Indianapous, Ind. Jacksonville, Fla. Kansas City, Mo. Knoxville, Tenn. Little Rock, Ark. Los Angeles, Calif. Louisville, at. Memphis, Tenn. Michigan City. Ind. Milwaukee, Wis. Minneapolis, Minn. Missoula, Mont. New Orleans, La. Newtown, Conn. New York, N. Y. Oklahoma City, Okla. Omaha, Nebb. Philadelphia, Pa. Phoenix, Ariz. Pittsburgh, Pa. Portland, Ore. Providence, R. I. Richmond, Va. Rochester, N. Y. St. Louis, Mo. Salt Lake Crrr, Utah San Antonio, Tex. San Francisco, Calip. Schenectady, N. Y. Seattle, Wash. Spokane, Wash. Tampa, Fla. Toledo, Ohio Trenton, N. J. Tulsa, Okla. Washington, D. C. Wichita, Kan. Wilkes Barbe, Pa. Worcester, Mass. Juarez, Mexico Mexico, D.F., Mex. CONVECTORS--Attractive, easy-toinstall. 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 64 in. long; 20,24,26, 32, and 38 in. high. BASEBOARD---New snap-on front base board for forced hot water, steam or vapor heating. Fits flush with floor. 10 and 12 in. high. Shipped in 10-ft lengths for easy, on-the-job cutting. Ele ments shipped in 1 to 6-ft lengths. FIN-VECTOR <g)--Oan be installed at any level over 4 in. from floor to ceiling. Three style covers: Sloping Top, Flat Top, Expanded Metal. Exclusive ad justable nook-and-link hanger. 1, 2 or 3 tiers high. Two tube sizes, 1% and 2 in. steel pipe or copper tube. HEATING-COOLING UNITS--For in dividual room heating with steam or forced hot water; cooling with chilled water; ventilating; heating and ventilat ing; or cooling and ventilating. Three different sizes can be floor, wall, ceiling or inverted mounted. Capacities at 2 lb steam, 60F entering air: 21,000 to 84,000 Btu. 1541 Vari-Temp Heating-Cooling Unit C. A. Dunham Company Type V Unit Heater Type C Unit Heater Type R Unit Heater Heating Systems UNIT HEATERS--Type V. Horizontal Discharge. II sizes for any job. Capaci ties at 2 lb steam, f>011' entering air: 10.500 to 360,000 Btu per hour. . UNIT HEATERS--Type C. Vertical Discharge. Four types of diffusers. Made in 7 sizes. Capacities at 2 lb steam, 60F entering air: 28,800 to 492,000 Btu per hour. UNIT HEATER--Blower, Type R. 5 different types of mountings for floor, wall, ceiling, inverted or platform. Mix ing dampers, by-pass dampers, filter sections available. Capacities at 2 lb steam, 60F entering air: 58,000 to 822.500 Btu per hour. UNIT HEATERS--Gas-Fired and Duct Furnaces. One-piece, gas-tight alu minized steel combustion chamber and heat exchanger. Made in 8 sizes for 50,000 to 230,000 Btu per hour input. VACUUM PUMPS--Pull and maintain, at low amperage, up to 26 in. vacuum without dependence on close clearances. Only ONE principal moving part. Single motor easily handles BOTH air and con densate removal. Low 9,Vjj-in. return line connections. Full range of sizes from 2,500 to 65,000 EDR, both single or duplex units. CONDENSATION PUMPS--Redesigned pumps feature new mechanical seal that eliminates stuffing box packing worries. Capacities up to 50,000 EDR at 20 lb discharge pressure. Single and duplex models. Model Ct Vacuum Hump 1542 Type CH V Condensation Pump C. A. Dunham Co. Heating Systems Traps and Valves Vo. HO Radiator Value No. W Radiator Valve Types OB and OBS Bucket Traps Type 1HORadiator Valve No. 600 Radiator Valve RADIATOR TRAPS--For all types of low pressure steam heating systems. Body and cover of cast bronze, disc of Monel metal. Available in 6 patterns. Capacities from 200 to 700 EDR. THERMOSTATIC TRAPS--Trap has , cast brass body and cover; replaceable stainless steel valve and seat; disc of Monel 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 exchangers. Float, copper; float valve and seat, Monel metal. Up to 15 psi gage working pressure. Sizes: 1, 1J4> 1)4 and 2 in. with capacities from 100 to 5,750 lb of condensate per hour. INVERTED BUCKET TRAP--Body and cover of high tensile iron castings. Valve and seat (renewable and inter changeable) are specially hardened, cor rosion-resistant steel. Operating pres sures 20 to 150 lb gage. Sizes 34, 1 and 1)4 >n. Capacities from 220 to 5,600 lb of condensate per hour. SPRING PACKED VALVES--For lowpressure systems up to 15 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 con struction (no packing spring or stuffing box) provides tight permanent seal. Sizes: to 1)4 in. in 4 body patterns. HOT WATER VALVES A complete line of Dunham Circulator Valves, Balancing Elbows and Fittings, Vent Tees and Union Elbows and Con nectors are now available. PACKED STEM VALVES--For lowpressure steam systems and hot water systems up to 60 lb. Cast brass body and bonnet. Sizes: l/i to 2 in DUNHAM HEATING SYSTEMS VARI-VAC DIFFERENTIAL HEATING saves up to 40 per cent on fuel because Vari-Vac automatically provides the exact amount of heat needed by using a con tinuous flow of sub-atmospheric steam at temperatures that vary with the weather. METRO single-riser method of piping, costs less to install and maintain. Provides continuous path for flow of steam from top to bottom of building. Con tinuous pipe runs down through overlying rooms and is offset into each room into Convectors or Baseboard radiation. The C. A. Dunham Company manufactures a complete line of quality steam and hot water heating equipment. For catalogs and literature write: Dept. HVAC-54, C. A. Dunham Co., 400 W. Madison St., Chicago 6, 111., or see your local Dunham Sales Engineer. . 1543 Heating Systems Hofwate Hoffman Specialty Mfg. Corp. General Office and Factory Indianapolis, Ind. Sales Representatives in Principal Cities 500 UNIVERSAL AUTOMATIC AIR VENT FOR WATER OR STEAM Hygroscopic discs automatically open to permit venting of air---automati cally close against loss of water or steam. Can be taken apart for cleaning without draining the water system. Max. water press. 50 lbs. Max. steam press. 15 lbs. Size conn: 34 in. RADIATOR AIR VALVES FOR STEAM AND VACUUM SYSTEMS No. 40 No.il/fo.43 No.roA and No. 45 No. 71A No. IA No.lA No. 3 No. 40 Steam--Hoffman patented tongue syphon--34 in. connection--fixed port. No. 41, 43 and 45 Steam--Straight shank for convectors--telescopic syphon--J4 in., in., and 34 in. male, 34 in. female connections. No. 70A Steam--Tongue Syphon--Non adjustable, single port--J4 in. connection. No. 71A Steam--Straight shank for convectors--telescopic syphon 34 in. connection. No. 1A Steam--Tongue Syphon--ADJUSTABLE air opening--34 in. connection. No. 2A VACUUM--Tongue Syphon--ADJUSTABLE air opening--34 in. connection. No. 3 Steam--For Airline or PAUL systems--34 x 34 in. conn.--union tail piece. STRAIGHT SHANK VENTING VALVES LOW, MEDIUM AND HIGH PRBSSURETHERMOSTATIC. traps ____ ^ Low P_r_e__s_s_u_ r_e sMceudtiuumm rPrcressssTuire Higmh _Pre_s__s_u__r_e Low pressure traps have brass bodies, caps and union nut and tailpiece. 17C is made in Angle, Swivel and Vertical patterns. 8(5 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 15ib pressure 34 in. connection No. 8C Capacity 400 sq ft EDR 25lb pressure 34 in. connection No. 9C Capacity 700 sq ft EDR 25lb pressure 1 in. connection Medium Pressure Nos. 8 &9 and High Pressure Nos. 8H & 9H have all bronze bodies and caps with union nut and tailpiece. Thermostats are 6 diaphragms of special non corrosive metal. Thermostats and seats are renewable. 34 iu- sizes are furnished in Angle, R.H., L.H. and Straightway patterns, others in Angle only. Medium Press. 50 lb limit. High Press. 125 lb. -5Z.S - - -- --- Traps 5 15 25 8 h: 100 180 235 400 9 vs* 125 - 225 300 490 225 350 450 650 --------1-*--------- --3--2-5-------5--0-0--------6-2-5-------8- 5-0 ' Traps 8H 8H 9H 9_H * 25 235 300 450 625 i 50 / jOD 400 550 490 650 650 875 o8o5u0 \ i1125 FLOAT TRAPS, DIRT STRAINERS AND SUPPLY VALVES 325 590 720 950 1250 No. i No. iA No. 16A No. H No. 73 No.79andlNo.'7 No. 4 Steam Mains--Will not close against water -34 in. male, 34 in. female con- nection. No. 4A Steam Mains--Float closes against water 34 in. male, 34 in. female con- nection. - No. 16A VACUUM Mains--Float closes against water--34 in. male, 34 in. female conn. No. 75 Steam Mains--Medium systems--has float--34 in. male, 34 in. female con nection. . No. 76 VACUUM Mains--Medium systems--has float--34" male, 34" female conn. No. 75A Steam Mains--Large systems at low pressure--has float--34 in. male, 34 in female connection. . No. 76A VACUUM Mains--Large systems low pressure--has float--34 in, male, 34 in female connection. No. 74 Unit Heater Vent Valve--Operates 0 to 35 lb. Vents air at any pressure and whether rising or falling--used on steam mains--34 in. male, 34 in. female conn. No. 79 Hot.Water Vent Valve--Positively removes air from piping of any hot water system. Max. press. 75 lb--34 in. male, 34 in. female connection at base and tap ped at top for 34 in. pipe connection. No. 791--Max. Press. 35 lbs Size conn: 34 jD- No. 60 Vacuum Breaker--For medium and low pressure steam systems. Set to open.at 2 in. (mercury) vacuum. 34 in. male iron pipe connection. 1544 V 50 Series Float and Therm. Traps are available in pressure ranges to 125 lbs. 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 12,000 lbs. condensate per hour. Radiator Supply Valves are made in sizes from ^ to 2 in. in Angie, R.H., L.R and Straightway patterns. Brass bodies, union nut and tailpiece. Nos. 180 and 185 have non-rising handles. Both are packless. No. 186 is especially suited to vacuum systems. ^ Hoffman Dirt Strainers are self-cleaning Y type. Brass strainer cylinders and cast iron body. Sizes ^ to 2 in. for 125 lb pressure. Should be used in line ahead of all float and thermostatic traps. Also available with monel metal strainers. CONDENSATION AND VACUUM PUMPS Hoffman pumps are available in varying capacities, D.C. and A.C. current, single, two, or three phase and in pressures up to 60 lbs. Vacuum Pumps Single and Duplex Units Capacities from 2,500 to 100,000 sg ft EDR Condensation Pump Single anil Dapie* Units Capacities from 1,000 to 160,000 sgftEDR 1545 Hoffman Specialty Mfg. Carp. Heating Systems US.E? HOFFMAN "PANELMATIC" HOT WATER SYSTEM CONTROLS Designed for all Types of Radiant Heating The Hoffman method vastly improves the ordinary forced hot water system by the application ot Continuous Circulation. This method permits a smoothly modulated regulation of the heat supply. The Control Valve closes and the circulating stream by-passes the boiler as long as the heat requirements are satisfied. When the circulating water begins to lose heat, the Control Valve is slowly opened by the Controller, permitting hot boiler water to enter the system. Thus, the delicate precision of the Hoffman Controller smoothly varies the temperature of the contin uously circulating water so that the heat supply is always equalized with the heat loss and room temperature remains constant throughout all changes in the weather. There is no type of building to which Hoffman Hot Water Controlled Heat cannot ' be applied. The system permits zoning of apartments, institutions, large residences and factories, thereby assuring a distribution of heat in di- ` rect relation to either personal temperature preference or to the functional activities of the building. Boiler Connections Tor One or Two Pipe Systems HEATING COMFORT IS ACHIEVED BY THESE SIX HOFFMAN SPECIALTIES Orifice The Panelmatic Controller The brain of the Hoffman system. It - automatically maintains a constant com fort condition regardless of the outdoor temperature. Its accurate balancing mechanism electrically opens or closes the Hoffman Hot Water Control Valve as required. Outdoor Temperature Anticipating Bulb This Bulb transmits changes in the outdoor temperature to the balancing mechanism of the Panelmatic Controller. Hot Water Temperature Bulb . Accurately relays temperature changes of the supply main water to the balancing mechanism of the Hoffman Comfort Controller. A calibrated orifice used toCbiarclaunlacetintghePicpiercOuirtsifictherough the boiler and through the Hoffman circuiting pipe. Opens only sufficiently to HsuoptpWlyattheer Ccoonrrteroclt Vaamlvoeunt of water to maintain the proTpheerrmwoamteer tteerm. pSerhaotuulrdebbeeiinnsgtaclilrecdulaabteodutth6rionu. gfrhomthesusbymsteermge.d Water Temp. Bulb. Hoffman Hot Water Circulator A centrifugal pump of prescribed capacity and low in power consumption. Usually installed in the return main and continuously circulates the water through the system. 1546 Hoffman Specialty Mfg. Corp. Heating Systems *h"wTM< HOFFMAN PANEL-FLO VALVES for adjusting; the flow of water through individual Panel Heating Coils Gives a wide range adjustment of water flow to each coil with out affecting the heat output of the other coils--can cut flow through coil as much as 60.per cent. . . WITH NO APPRECI ABLE CHANGE IN CIRCULATING PUMP HEAD. Has indicating Dial for accurate settingof each coil--or adjusting any coil withoutaffectingtheother coils. % io. pipe connection. Series i HOFFMAN INVERTED BUCKET TRAPS Working Pressures to 200 lbs 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. HOFFMAN PRESS. REDUCIN VALVES Series 700 Max. Press. 200 psi.. Low Press. 1 to 25 psi. Series 710 Max. Press. 250 psi., Low Press. 5 to 80 psi. Series 715 Max. Press. 250 psi., Low Press. 2)4 to 25 psi. Series 720-S & 720-W Max. Press. 250 psi., Low Press. 2 to 125 psi. Series 750 Max. Press. 250 psi.. Low Press. 2)4 to 25 psi. Choice of types specifically engineered for your needs--continuous service, or, for tight sealing against low pressure side when there is no demand--and with typi- cal Hoffman features of design. Scries no Seriee 1100 w HOFFMAN TEMPERATURE REGULATORS Series 1100--for steam pressure to 150 lb per sq in. Standard temperature range--80 F to 250 F. Other ranges available on special order. Self-motivated. Hydraulically formed bellows of selected material. Rugged construction. For water heat ers, convectors, fuel oil preheaters and other similar applications. HOFFMAN "ZONET" ZONE CONTROL Series 1200--Zonet systems or packages for Steam and Hot Water consist of heat anticipating Room Thermostat, motor operated Globe Type Valve, Transformer, Fuse Block and fuse, and in the case of steam zoning, a Vacuum Breaker. The motor operated, two position, single seated, packed globe type Valve (illustrated) is available in sizes from )4 in. to 6 in. Maximum service pressure: steam 100 lbs per sq in., water 150 lbs per sq in. HOFFMAN ELECTRIC CONTROLS Hoffman Room Thermostat Hoffman offers a comprehensive selection of fine quality electric controls for steam, hot water and warm air heating systems. These controls are especially suited for use with other famous Hoffman heating system specialties and provide one source of supply and one responsibility for satisfactory performance. Illustrated are two popular control units, typical of the complete Hoffman line. 1547 Hot Water Limit Control Immersion Type i. ' Heating Systems st<*m ILLINOIS ENGINEERING COMPANY ueuerai unices and Factory: Chicago 8, 111. [ILLINOIS1 8EATING VSTII'" B a Representatives In Principal Cities ILLINOIS HEATING SYSTEMS ILLINOIS HEATING SYSTEMS, with or without control, in five general types, cover the complete range of vacuum and vapor heating requirements; each admits of modification to meet any special con dition in either. These systems include: GENERATION Control Systems--Type C .. . For independent boiler installations affording maximum fuel economy. CONTINUOUS FLOW Control Systems --Type A . For installations which require zoned control, or where steam is used for other than heating and domestic hot . water service, or where steam is supplied by Central Station Service, Pneumatic or manual operation. CYCLING FLOW Control Systems-- Type E For automatic or manual control of steam flow and pressures not only in vacuum systems but in one-pipe or two- pipe gravity installations as well. VACUUM SYSTEMS A two-pipe steam circulating system in which a standard vacuum pump is used to accelerate circulation, remove air and condensate from the system and return the condensate to the boiler. Suitable for any type of building, for industrial plants, or for groups of build ings heated from a central plant. VAPOR SYSTEMS A two-pipe system circulating steainat low positive pressures without any pump or mechanical vacuum producer. Recom mended for Residence, Small Apartment, and similar service. Gives rapid, flexible steam circulation. Series G Selective Controller Series Q Supply Valve 1 Illinois Float and Thermostatic Traps--Unsurpassed for draining ventilating unite, unit heaters, and for dripping mains and risers--wherever it is desirable quickly to vent air from the main as well as handle the water of condensation in quantity, whether hot or cold. Illinois Selective Pressure Control Systems--An entirely new and unique method of Steam Circulation Control . . . Heating Systems that set new standards in comfort, economy, simplicity and convenience of operation. Each system individually engi neered to meet exact requirements. Recorded fuel savings, without sacrifice of com fort, warrant your investigation. Illinois Radiator Supply Valve--Quick-opening, packless. Steam tight on 50 lb pressure. Large diameter of thread spool and machine cut threads make valve operation easy. Furnished in a complete line of sizes and patterns. Illinois Thermo Radiator Traps--Illinois Thermo Radiator Traps for vacuum, vapor and low pressure heating systems. Has cone type valve. Flushes thoroughly n" seats perfectly at all times. Valve and seat are of hardened steel alloy. The duplex diaphragm is of special phosphor bronze. Scientific design and rugged construction assure flexibility and long life. 1548 ILLINOIS ENGINEERING COMPANY 'oenera* wmces and Factory: Chicago 8, 111. Representatives In Principal Cities Type ES Fig. ttl Fig. tSO Illinois Motorized Valves (on and off)--Type E3--For auto matic control of steam temperatures and pressures to prevent overheating and conserve steam; to control fluid levels; and to regulate flow in hot water heating systems. May be oper ated by any automatic contact device or by manual switches. Furnished in three types. Pressure Regulating Valve, Semi-Steel Bodies, Bronze Trim-- Fig. 121--Furnished in either single seat or double seat type as service requires, for the control of steam, air or gas. dontrol spring is completely enclosed, protecting it from dirt and rust. Valves are furnished with proper size diaphragm and proper length spring to give satisfactory service under all operating conditions. Furnished also in weight loaded type. Non-return Valves--Fig. 260--Placed between boiler and header to prevent return of steam to boiler. Sensitive in operation. Extra heavy Bemi-steel bodies with bronze trim for 250 lbs steam working pressure. Bronze dash pot and water sealed pistons prevent valve sticking. Globe and angle patterns from 4 in. to 12 in. Illinois Thermostatic Traps for High Pressures--Series HG-- Maximum working pressure 150 pounds. Used where neat . appearance and compactness are desirable, as for trapping sterilizers or water stills in hospitals; steam jacketed kettles, coffee urns, wanning tables and for process work. Also used extensively for air vents on blast type drying heaters. Multi diaphragm of phosphor bronze. Heavy duty bronze body. Made in three sizes. These traps are also furnished for medium pressures. Steam and Oil Separators--Vertical Steam Separators__ Eclipse steam separators are made in both horizontal and vertical type, standard or extra heavy. Eclipse oil separators are furnished in the horizontal type and have a removable baffle plate to facilitate cleaning of baffle and keeping the separator's efficiency the highest point Illinois Steam Trap--Series 30--Valve and stem are separate from the bucket and operated only by the bucket at extreme top and bottom of travel--result--valve is always either full open or tight closed. Provided with continuous thermostatic air vent. No wire drawing or cutting of valve and seat which are of hardened steel alloy. Series HG 1549 Series SO Heating Systems Stfgg*!} *" Maid-O'-Mist, Inc. 3217 No. Pulaski Road Chicago 41, 111. Manufacturers of Automatic Air Valves for Hot Water Heating Systems Products: Automatic air valves for hot water heating systems; automatic humidifiers -for steam or hot water; automatic humidifiers for warm air furnaces; steam boiler water line controls; water line float control valves; liquid gas and air strainers. AUTO-VENT Air Eliminators Maid-O'-Mist Auto-Vents permit auto matic venting of the air which causes circulation trouble and heating waste. More and more, contractors who value satisfied customers are installing these trouble stoppers. No. 7 Auto-Vent. For mains, pipe lines, unit heaters, convectors, coils, etc. De signed for vertical mounting only. Size 4jf) in. x 2J4 in. with % in. I.P. female connection. Made of brass and equipped jv t Auto-Vent a self-closing, float operated valve. All working parts, including valve and Venting trapped mains and circulating lines copper float, 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 un affected by high temperatures, oil, anti-freeze, etc. For pressure not exceeding 75 lbs. No. 77 Auto-Vent. Identical to No. 7 Auto-Vent, except for a M in., I.P. side opening to permit its use on overhead pipe lines, coils, etc., where head room is factor: Ideally suited for Diesel engine and cooling manifold use, where vibration demands secure mounting. No air chamber required. Auxiliary Equipment: No. 7X--bonnet assembly for No. 7 and 77; No. 777 self closing valve core; No. 7A--connector for safe waste. . noizt AUTO-VENT--- 1. I . BEn 4 ip nipple--1r ELL---------------------------------- ^ No. 27 Auto-Vent -suPPur No. t7 Auto-Vent For venting connector radiate** For convectors and free standing radiation. Designed for horizontal mounting only. Size 3 in. x2in. with % I.P. female connection. Construction, and internal working parts are same as in No. 7 Auto-Vent, but for horizontal mounting. Made of nonferrous metals and designed for pressure not over 50 lbs. No air chamber required. Auxiliary Equipment; No. 27X--bonnet assembly for No. 27; No. 7A--connector for safe waste. Write for price sheet and descriptive literature. 1550 Maid-O'-Misl, Inc. Heating Systems No. 67 Auto-Vent No. 67 Auto-Vent For convectors and baseboard radiators. Designed for vertical mounting only. Size 3^6 in. x 1in. with a % I.P. male connection. Designed for limited space, small, self-closing, float operated valve may be installed in trouble spots pre viously 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 lbs. Where a Safe Waste is needed, specify No. 7A connec tor fitting. For venting convector radiators w IVO. 72 Auto-Vent No. 72 Auto-Vent For convectors, baseboard and free standing radiation. Designed for both vertical and horizontal mounting. Size 1% in. x ^ in. with in. I.P. male con nection. No. 72 Auto-Vent is a fast vent ing 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 water logging when installed in either vertical or horizontal 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 are 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. For baseboard radiation Balancing No. 14 and No. 15 Balancing Valve Adapter Units for Hot Water Heating Systems Maid-O'-Mist Valve Adapter Units make any copper, bronze, or cast iron tee a balancing valve. These units, quickly sol dered or sweat fitted into copper and bronze tees or threaded into cast iron tees, regulate hot water flow through radiators, convectors, baseboard panels, radiant coils, return mains, and No. n No. is branches. Can be inserted in side outlet or run of tee of same No.n for copper and bronze Pipesize fco complete either a straightway or angle balancing ie3-Nominal pipe^sises valve. Full, free flow of water through the tee is. possible. No.isfort&s*SuL`w, ince there is no inside reduction of pipe diameter, there is no i", W. water restriction except for the balancing required. This per mits the use of additional balancing in a hot water system without preliminary planning. Precision made of non-ferrous metals. Simple balancing requires only a screw driver. 1551 Heating Systems * vKti" Jas. P. Marsh Corporation Dept. 5, Skokie, IUmois Branches in Principal Cities Marsh products include: Pressure, Vacuum and Compound Gauges; Dial Thermometers; Steam Traps; Vents; Packless Radiator Valves and other heating specialties; Tri-trol Regulators; Electrimatic Refrigeration Water Regulators and Solenoid Valves. Radiator Traps--These highly efficient radiator traps are equipped with a phos phor bronze diaphragm charged with a Condensation is discharged through a float-operated valve located at the lowest point inside the trap body. Air vent is located in a by-pass in the cap or cover of the trap. Air passes through;a passageway and out through the trap outlet. Construction permits removal of mechanism without disturbing the piping. Thermostatic Diaphragm Radiator Trap volatile fluid making them equally effi cient for use on pressures below atmos pheric up to 15 lbs pressure. Also other traps available up to 125 lbs pressure. Packless Radiator Valves--The metalto-metal seal of Marsh Radiator valves makes them truly packless. They contain no packing of any kind to wear, crack and deteriorate. Proved by many years of service. Easy to operate. Close on less than one turn. Individually tested. Adaptable for hot water as well as steam heating systems. Float and Thermostatic Trap Marsh Inverted Bucket Traps are ideal for all types of hospital and kitchen equipment or similar service where a Jas. P. Marsh Corporation Heating Systems sSSittes Marsh Pressure Gauges--The Marsh ASME standard, low pressure gauge will contribute to the economy and im prove the operation of any type of steam boiler. It is finely built throughout and is available with the Marsh "Recali brator" for quickly and easily resetting the hand to zero when the gauge is knocked out of adjustment. Marsh Electrimatic Refrigeration Valves --The Marsh Electrimatic line of re frigeration valves includes condenser water regulators for ammonia. Freon or methyl chloride service; temperature actuated valves, packless solenoid valves, and other related products. Marsh Gauges include vacuum and com pound types in a wide range of designs covering all services and pressures. Over 85 years of gauge manufacturing has reached its highest achievement in the Marsh "Mastergauge" for use where high pressures and temperatures are present and where maximum stamina and accuracy are essential. Marsh Dial Thermometers--The same basic refinements found in Marsh Gauges are found in Marsh Dial Thermometers. Bourdon tube types are available in self- The popular Electrimatic Type WP direct acting piston type regulator is il lustrated. All working parts are Monel and stainless steel and body is special, non-porous brass alloy. Advanced fea tures are: stainless steel piston; heavier cushion spring; tight seal; water behind piston dampening vibration; Monel 3eat eliminating dezincification; sturdy, 2 ply, 300 lb-test bellows; open yoke per mitting easy adjustment and rotatable to provide for mounting regulator in any position. Other types--pilot operated-- available for heavy ana extreme duty. Marsh Electrimatic Solenoid Valves are made in both direct-acting and pilotoperated types in % in. and ^ in. or Packless Radiator Valve Marsh Float and Thermostatic Traps-- One of the many types of Marsh Heavy Duty Float and Thermostatic Traps is illustrated. These traps are designed for removal of air and condensate from steam mains, branches, or risers, unit heaters, steam coils, etc. The size and weight of the trap permits installation in the pip ing without any other means of support. Inverted Bucket Trap considerable volume of condensate is handled. Traps are self-venting and have large water capacity thus assuring un usually high efficiency in removing con densate, air and gases. contained and distant reading instru ments, vapor-tension or gas filled. All ranges up to 400 F are covered. "Recali brator" is standard in all bourdon tube types. Ask for catalog information. ifice sizes respectively. They are of pack less, tight seating construction with impregnated coils to withstand frost and moisture. 1553 Heating Systems v Specialties W. H. Nicholson & Company Main Offices and Factory: 211 Oregon Street, Wilkes-Barre, Pa. SALES REPRESENTATIVES IN U. S. A.. CANADA. AND MEXICO AT: Albany, N. Y. Albuqtjebque, N. M. Atlanta, Ga. Bala-Ctnwyd, Pa. Baltimobb, Md. Baton Rouge, La. Bi rmtngham, Ala. Buffalo. N. Y. -Chicago, HI. Cincinnati, O. Cleveland. O. Columbus, O. Corpus Chbxsti, Hanoveb, Pa. Try. Houston, Tex. Denver,. Colo. Indianapolis, Ind. Des Moines, la. Kansas City, Mo. Detboit. Mich. ' Kingston, Pa. El Paso, Texas KIVnNoOxXvViilUlieS, Tx ebnnnn. Evansville, Ind. Los Angeelleess, Cal' . Fobt Worth. Tex. Mexico, D.F. Frederick. Md. Milwaukee, Wis. Grand Rapids, Minneapolis, Mich. Minn.. Gbeensbobo, N. C. Mobile, Ala. Greenville, S. C. Montreal, Que. Needham, Mass. Salt Lake New York,N. Y. Citt, U. Oak Ridge, Tenn. San Francisco, Cal. Omaha, Neb. Seattle, Wash. Orlando, Fla. Spokane, Wash. Prceuoarwia, IuI<Il.. St. Louis. Mo. Pittsburgh, Pa. Sumter, S. C. Ponca City, Okla. Syracuse, N. Y Portland, Me. Toronto, Ont. Portland, Ore. Tucson, Arizona RtUiCcHhKmUoNnOd,, V*a. V*aanmc;uouuvvbebh,,.dB.. C. Rochester, N Y. Washington, D. C. Rutherford, N. J. Yakima, Wash. STEAM. WATER. AIR, OIL AND GAS SPECIALTIES TRAPS Thermostatic: Steam, to 250 lb. Expansion: Steam, to 2501b. Weight-Operated; Steam, Air, Gasoline; to 1500 lb. Piston-Operated: Steam, to 650 lb. Radiator: to 25 lb. SEPARATORS: Steam, Air, Gas to 250 lb. STRAINERS: to 600 lb. VALVES, Cylinder Con trol: Air, Gas, , Oil, Steam, Water; hever, Foot, Solenoic, MotorOperated; to 5000 lb. FLOATS, Welded: 2 in. to 14 in. diam.; Pressures to 4800 lb. ENGINEERING BULLETINS AVAILABLE ON ALL NICHOLSON PRODUCTS NICHOLSON INDUSTRIAL STEAM TRAPS 5 Types for Every Heal, Power and Process Application A survey of large users of Nicholson industrial steam traps showed these main reasons for the increasing standardiza tion on Nicholson units for specified applications: 1) Operate on lowest possible tempera ture differential; no waterlogging. 2) Have 2 to 6 times average drainage c&p&city. 3) No need to change or adjust valves for varying pressures. 4) Record low for steam waste. 5) Maximum air-venting capacity. Nicholson installations have repeat edly shown production increases up to 30 per cent. Some typical unit applica tions: plastic moulding platens, dry kilns, steam mains, unit heaters, radia tors, pipe coils, drips, hot water heaters, driers, jacketed kettles, cookers, coffee and hot water urns, dish heaters, vege table steamers, bakers' proof boxes, steam tables, sterilizers, ironers, presses, mangles. . Types A, AHV and AU, shown on this page, are for pressures from vacuum to 200 lb. Bronze construction, aluminum painted. BULLETIN 853 Max. Capacity in Lbs. per Hr. at Various Pressures--Types A, AHV, AU type AHV Size, inches )4-5|-44 1 l lb. 865 865 1020 2 lbs. 1220 1220 1440 5 lbs. 1015 1915 2270 to lbs. 2695 2695 3190 15 lbs. 3290 3290 3900 20 lbs. 3780 3780 4475 40 lbs. 5290 5290 6250 SO lbs. ~5885~ 5885 6955 60 lbs. 60 lbs. 100 lbs. 125 lbs. 150 lbs. 175 lbs. 200 lbs. X 6400 6400 7590 7310 7310 8660 8120 8120 9600 8925 8925 10,570 9775 9775 11,590 10,400 10,400 12,310 11,090* 11,090 13,100 See Note A, next page - LIST PRICES--TYPES A. AHV. AU Size, Inches )4-54-)4 54 1 Types A and AHV With Bellows of Bronze Monel Stain less $17.60 $20.90 $24.90 19.05 22.40 26.40 21.30 23.65 28.65 Type AU With Bellows of Bronze Monel Stain less $19.05 $22.40 $26.40 20.50 23.85 27.85 23.45 26.80 30.80 Valve Orifice, Inches `A' W. H. Nicholson & Company Heating Systems * Specialties Nicholson Industrial Steam Traps, Types B and C maximum capacity in lbs. per hr. at various pressure differentials Size A' Xm 1*-- 1)4'--2' 1 lb. 1140 1695 2120 3200 2-lbs. 1610 2385 2985 4510 5 lbs. 2530 3760 4700 7100 10 lbs. 3560 5290 6610 9990 15 lbs. 4350 6450 8070 12,200 20 lbs. 4990 7420 9260 14,000 40 lbs. 6980 10,350 12,960 19,600 50 lbs. 7775 11.540 14,430 21,800 MAXIMUM CAPACITY IN LBS. PER HR. AT VARIOUS PRESSURE DIFFERENTIALS Size W 1--1)4 1)4'--2' 80 lbs. 9650 14,350 17,930 27,120 100 lbs. 10,720 15,910 19,900 30,100 125 lbs- 11,800 17,500 21,880 33,100 150 lbs. 12,920 19,190 23,980 36,300 175 lbs. 13,750 20,400 25,500 38,600 200 lbs. 14,640 21,720 27,200 41,100 225 lbs. 15,380 22,800 28,500 43.200 250 lbs. 16,090 23,870 29,850 45,150 60 lbs. 12,560 15,710 23,750 C STEEL 300 lbs. 17,400 25,820 48.900 Note A: Capacities shown are maximum with valve orifice wide open for 1 hr. with adjustment made for temperature and conditions of efflux. To permit intermittent discharge, and handling of peak loads at start -- of operations, select traps to handle not more than 50% of capacities shown. Types B and C are for pressures from vacuum to 250 lb; semi steel, aluminum painted. Type C is also furnished in cast steel, with stainless steel bellows, for pressures to 300 lb with superb heat up to 500 deg total temperature. For complete. details BULLETIN 853. ' Type B TypeC Size, Inches Semisteel With Bellows of . Semisteel With Bellowh of Cast Steel With Bellows of Bronze Monel Stain less Bronze Monel Stain less Monel Stain less A' $25.85 x* 33.90 1'--1)4' 40.40 IX'--S' 59.80 $29.20 38.30 43.95 64.45 $33.70 45.25 50.15 71.10 $25.85 33.90 40.40 59.80 $29.20 38.30 43.95 64.45 $33.70 45.25 50.15 71.10 $41.35. $45.45 53.70 60.30 63.00 69.65 91.00 97.65 Valve Orifice, Inches H* A' if Types A, AU and C are made in angle type only, with hori zontal inlet and vertical outlet. Type AU has union connection Type C on inlet. All three types drain completely when cold and will not freeze. Type AHV is especially applicable to drainage prob lems where necessary or desirable to have all piping run horizontally or vertically, or close to floor, wall or pillar. Type B, made with horizontal inlet and optional horizontal or vertical outlet, offers either angle or horizontal straight-through con nections. Types AHV and B traps are not freezeproof. ' NICHOLSON TYPE R RADIATOR TRAPS D--*1 Thermostatic bellows type; feature bal anced vapor-pressure principle and max diam. valve orifice. Bronze bellows; brass body, cover, union, nut; nickel alloy valve, renewable stainless steel seat. Two angle types for 200 and 400 sq ft EDR, Seria tA vapor and vacuum; r and 1-hand corner types for 200 sq ft. Pressure to 25 lbs. BULLETIN 452. _________ Series 2A 2A 2R & 2L 4A 4A DIMENSIONS AND LIST PRICES. TYPE R TRAPS Size w X VX? 54 Last Price $5.30 5.65 6.00 7-50 7.95 A 2 s% 3 3)4 B 1)4' 156 H iH 156 c 2Hm 2% 314 3H 3A D 2M' 2H 2U' m 2)4' E W CAPACITIES IN SQUARE FEET EDR Weight 154 lbs 1% 1 y. RIGHT TRAP-SERIES 2R LETT HANDTRAP-SERIES 2l SERIES AND SIZE PRESSURE DIFFERENTIAL--LBS. PER SQ. INCH H1 A 1 1 D4 1 2 5 10 15 25 H'A54'2A, )4*2RA2L 85 120 W&'A'iA 165 1 230 165 | 200 | 235 330 | 400 1 465 370 730 530 640 1050 1300 840 .1640 Note B: Ratings are in accordance with recommended standards of Steam Beet Equip. Mfr'e Atm. Select trap directly from table for the lowest pressure dif ferential that may exist in the system. * 1555 Heating Systems Specialties Ohio Brass Company MANSFIELD, OHIO EOUl%tEMP Versatile New Valve for Hot Water Heating Systems and Air Conditioning Provides for balancing, tight shut-off, venting, draining and thermometer well all in one compact valve. . 1. ADJUSTABLE FLOW--Easy adjust ment of flow for balancing. Full open to tight shut-off possible. , 2. TIGHT SHUT-OFF--Valve can be shutoff by a 90 degturn of stem. Rubber VENTING. O--R D---R---A--I-N---I-N--G-- IN UP RIGHT POSITION Figure 1. Automatic vent installed in top drain. Figure 2. Bottom drain plug removed for. draining of system. Valve may be operated with Allen wrench from above. "O" ring on disc makes a leaktight closure. 3. BUILT-IN THERMOMETER WELL --O-B EQU ATEMP has a thermometer well drilled into the stem, providing a handy means for accurate balancing. 4. TAMPER-RESISTANT CONTROL-- EQUATEMP setting is with Allen-type wrenches* (not normally available in the home). Same wrenches fit all size valves. Figure 1 O Figure 2 ' VENTING OR DRAINING IN INVERTED POSITION Figure 3. Automatic vent installed in bottom drain. Figure 4. Top dram plug removed for draining of. system. Valve may be operated with Alien- wrench from below. 5. VARIABLE VENTING OR DRAIN ING--For convenience EQUATEMP can be installed in upright or inverted posi tion. Top and bottom drain plugs allow venting or draining in either floor or ceiling installation. Figure $ Figure 4 6. EQUATEMP MANIFOLD FITTING --Available with three or four outlets. May be combined to form manifolds for' any desired number of valves. Allen wrench furnished with each 24 valves. Available COPPER-TOCOPPER No. 37 "H H H ROUGHING-IN DIMENSIONS A Bc Sizes Avail- able m 2K 156 2% % % 2% 3H 1% 116 SCREW TYPE No. 38 8 1 IK IK A 2K 9% 2H VA 3K Bc m 3 146 SK 2M, 3H 2K For additional information, please write to Ohio Brass Company, Mansfield (1), Ohio, for EQUATEMP Folder. 1556 1)4 IS 2K 2% Heating Systems Hot wt Sarcotherm Controls Inc. Empire State Bldg., New York 1, N. Y. Representatives in Principal Cities, Factory at Bethlehem, Pa. Fully automatic and completely inte grated control systems for any type of heating, direct by outside temperature. Sarcotherm Control for Hot Water and Radiant Heating System. Hot Water and Radiant Heating Sarcotherm provides a carefully engi neered control system for radiant or panel heating which is fully modulating, and allows continuous circulation. The customary lag of conventional room thermostats is eliminated with the com fort control "Thermoray" sensitive to both convection and radiation. For Forced Hot Water Heating System for garden apartments, housing develop ments, hospitals, and institutional build ings, Sarcotherm provides a completely zoned control system, including auto matic night set-back and automatic morning pick-up. Steam Heating Systems The Type "W" Sarcostat Control sys tem automatically proportions the amount of heat supplied to the actual need for any given weather condition. The control is fully modulating, and complete program control panels are provided to meet any control cycle re quired. Engineering Service Consulting Engineers and Contractors are invited to consult with our Engineer ing Staff on any proposed control system. There is no obligation. W" Sarcostat Control am Heating System. 1557 Heating Systems steam Sarco Company, Inc. Empire State Bldg., New York 1, N. Y. Branches in Principal Cities SARCO CANADA LIMITED, 611 Gerrabd St., E-, Toronto 8, On?. PRODUCTS--A complete line of Specialties for Steam and forced hot water Heating Systems, and automatic control for same, combined with a competent engineering service to architects and heating engineers to assist them inprovidingmodern heating. SARCO RADIATOR TRAPS Type H is the standard radiator trap for vapor and vacuum systems. It is. equipped with the well known Sarco heavy wall bellows, drawn from flat blanks and helically corrugated in our own plant. It operates noiselessly and positively at pressures from highest Radiator Trap, Tape H vacuum to 25 psi. Body and cap are of brass, natural brass finish; self-aligning valve head and re newable seat of hard bronze; union connection on inlet. In 4 in. size available in angle, straight or offset patterns, f in. angle and straight, 1 in. angle only; also h in. ana f in. vertical. Catalog HV-150A. SARCO RADIATOR VALVES Sarco offers two types of valves; bellows packless type 40 wherein the valve stem is sealed by a standard Sarco bellows, positively preventing air leakage into the heating system; also "spring-packless" type SM. Both can be furnished with the modulating feature, including proportioning disc and indicating dial. Valves are made in angle and straight way patterns, wheel handles or lock shield. Also available for hot water systems. Bodies of all valves are brass, natu ral brass finish; outlet fitted with union connection; sizes f in. to 1 \ in. Catalog No. HV-150A. SARCO N-100 TRAPS Similar in style to Sarco Radiator Trap, the N-100 Thermo static Trap is suitable for operation at pressures up to 100 psi. Has full length element protecting shield to prevent abrasive action on bellows. Shield also protects element against dam age if removed while hot. Stainless steel renewable valve head and seat. Sizes | in. to 1 in. Also S-65 for pressures to 65 psi. Catalog HV-J90A. Float-Thermostatic Trap SARCO FLOAT-THERMOSTATIC TRAPS Sarco offers a wide selection of Float-Thermostatic Traps,} to 2} in. Available for pressures up to 200 psi. Traps 0-125 psi are equipped with built-in thermostatic air vents. High pressure 200 psi traps are equipped with external thermody namic air by-pass. Catalog HV-4S0A. SARCO INVERTED BUCKET TRAPS Sarco inverted Bucket Traps are also offered in a wide range of sizes and suitable for pressures up to 900 psi. Seats and valves are stainless steel and renewable. Traps are regularly furnished with built-in strainers. Built in automatic air vents are available at extra charge. Sizes } to 2 in. Catalog Inverted Backet Trap HV-S60A. 1558 Sarco Company, Inc. Heating Systems steam SARCO ALTERNATING RECEIVER A complete line of boiler return traps for vapor systems. Returns water of condensation to boiler automatically, thereby assuring positive return of water under all pressure conditions. Made in four sizes up to 14,000 sq ft of radiation. Catalog HV-165A. Same type available as a pumping trap for pressures to 100 psi. Alternating Receiver SARCO AIR ELIMINATORS For venting air from vapor systems at one centra] point in the basement. Available in three sizes, for systems up to 15000 sq ft radiation. All are equipped with float valves to stop water escaping through the vent and with check valves to prevent ingress of air when system is under vacuum. Also several types for hot water heat ing systems. Catalog HV-I70A. SARCO SELF-CONTAINED TEMPERATURE REGULATORS Sarco Temperature Regulators are simple, self-operated valves--the only self-contained units that use the uniform force of liquid expansion. No stuffing boxes to leak, no auxiliary "power" required; all moving parts are inside the equipment. Here again--a type and size for every purpose--for steam, gas, oil, water or brine for temperatures ranging from0 to300 F. Catalog HV-600A: Type TR-tl Standard for hot water storage tanks, fan unit3, etc. SARCO WATER BLENDERS AND TEMPERING VALVES For mixing hot and cold water to deliver automatically water at any desired temperature. Two models are available, type MB for showers, wash basins, etc., and type DB, a tem pering valve for use with submerged heating coils or tankless heaters. Catalog HV-800A. , SARCO SELF-CLEANING STRAINERS For use in pipe lines carrying brine, steam, oil, gas, water, ammonia or air. Have large free screening area with minimum resistance to flow. Steam or air strainers can be cleaned by blowing through without disassembling. Made in cast iron, bronze or cast steel for pressures up to 600 psi, with brass, stn. steel or monel screens. Available in sizes } to 10 in. Catalog No. HV-1S00A. 1559 5Heating Systems iU utie, Strong, Carlisle & Hammond Company 1392 West 3rd St., Cleveland 13, Ohio "STRONG" The Complete Steam Specialties Line 1. Standard In-Line Traps (Semi-Steel). 5. Open Bucket Traps (Semi-Steel). Inverted bucket type. Hi-Cap design. For all steam service, and particularly Parts on cover for easy removal without suitable for pulsating pressures. Also breaking pipe connections. All stain for draining water or other liquids from less parts. lines on air or gas service. Anum-Metl Trap Pipe Size Continu- Capacity No. (inches) ous at pei lhe/hr 070 A, M 125 490 170 At, Vi 125 955 271 'A, 1 ' 125 1230 Wwaht lbs 3M 7 7'A List Price J7.00 9.00 13.50 2. "Y" Type Strainers (Semi-Steel). Features perforated Monel screen and new V-shaped gripping lugs. 250 psi 450 deg steam. 400 psi cold, non-shock. Pipe Size (inches) X. K K X I \Y\ iX 2 2K 3 Wright Ibe Sizes K*in.. K*in. fur nished - with 60 z 50 mesh Monel cloth _ screens. Sizes K*in. to 3-in. standard with .027 perforated Monel. 1 2K zX 5X 8X UK 17 22 32 List Price $1.90 2.25 2.70 3.25 4.10 5.25 7.75 18.00 21.00 3. In-Line Blast Traps (Semi-Steel). Inverted bucket (open-float) and ther mostatic type. Hi-Cap design. Inte gral bi-metal, thermal operated vent. For rapid heating on unit heaters, cookers, etc. Anum-Metl seat, stainless bucket and working parts. Trap Pipe Size Continu Capacity Weight No. (inches) ` ous at psi 1be/hr lbs 070-T H, X 30 660 Z% 170-T HtH 30 1290 8 271-T X, 1 30 1760 9 List Price (8.60 12.00 17.50 seat guaranteed leakproof one year. Pipe Trap Size No. (in'-hes) 30 . 31 32 33 34 35 36 K X 1 IX IX 2 2M Continuous Capacity at psi lbs/hr 125 125 125 , 125 . 125 125 125 1230 1560 2750 6100 8700 11.500 27,300 Weight lbs 48 53 79 120 165 197 335 List Price $22.50 28.00 34.00 47.00 60.00 85.00 120.00 6. Type O & K Pressure Regulators (Semi-Steel). For steam, air and gas. Direct operated. Rugged construction) Fitted with special laminated, phosphor- bronze diaphragms and stainless valve and seat. ' Pipe Size No. (inches) Weight last lbs Price Type O X, X, X Initial pressure to 225 psi, 400 F, reduced S $15.00 Type K ranges 0-200. Initial pressure to 225 15 19.00 (illus trated) X1 XX IK psi, 400 F, reduced ranges from 0 to So 15 psi- 18 Type K an inte- 40 gral strainer. 40 20.00 27 00 38.00 42 00 7. Type C Pressure Regulators (Semi Steel), For installations requiring ac curate and dependable regulation. 4. Bottom Inlet Traps (Semi-Steel). Rugged, trouble-free inverted bucket type. All stainless working parts. Anum-Metl valve and seat. Self-clean ing action. Tran Pipes Size Continu No. (inches) ous at pai 171 K 125 80 K 125 81 X 125 82 1 125 83 IK \25 84 IK 125 85 2 125 Capacity Weight List Ibs/hr lbs Price 1230 7H $10.50 1700 16 17.00 3300 25 22.50 6100 35 30.00 10.200 54 37.00 15,400 82 55.00 32,000 117 73.00 Stainless trim, single-seated, pistonoperated, pilot controlled spring-loaded. Pipe Size No finches) Type C X . Weight . lbs From initial pressure 17 List Price $36.00 X to 250 psi, 450 F. For 17 39 00 1 reduced pressure 17 \x trofn 0 to 200 psi 40 43 00 4fi 00 2IK 2H 4 40 A writable in cast steel 4 series 30. 40 or 60 74 ttanges; pressure 600 98 psi: temperature 750 150 w-w 79-00 95-00 160.00 deg Complete Catalog Available on Request. 1560 Heating Systems s,iaut-ef Yarnall-Waring Company Manufacturers of Steam Specialties 133 Mermaid Ave., Philadelphia 18, Pa. YARWAY IMPULSE STEAM TRAPS Construction--Made entirely of bar stock Only one moving part, valve (F). For pressures to 400 lb, body, control cyl-, inder, valve and seat are stainless steel, valve and seat heat-treated; bonnet is cold rolled steel, cadmium plated; cap is tobin bronze. For 6001b, trap is all stain less steel. Operation--At low condensate tempera tures, bypass through control chamber (K) and center orifice of valve reduces chamber pressure and valve opens. At high temperature, condensate vaporizes in (K), increased volume builds up pres sure and valve closes. Light Weight--Need no support-- in. trap weighs only If lb. 2 in. weighs 8f lb. Small Size^ in. trap 2} in. long--2 in. trap, 4| in. long. Will not air bind.--Require no priming. Insure quick heating. Low Price--Often cheaper than repairing old traps. Factory set for all pressures to 400 lb (or 600 lb) without change of valve or List'Prices, Weights and Dimensions No. 50 Series--to 400 \b; 120 Series--to 600 lb Size Complete Trap Series 60 Complete Trap . Series 120 Weight Pounds Length Inches' seat. ' X' $15 $ 25 IX 900,000 Bold. Stocked by 200 distributors. y 22 37 2 Send for descriptive Bulletin T-1H0. YARWAY FINE-SCREEN STRAINERS im. IX' IX* 2* 31 48 68 90 62 2K 3X 80 114 4 5H HI 150 m *x Offer better protection against rust, scale and dirt for all steam equipment. Ten standard sizes M in. to 3 in. Cad mium plated bodies. High grade Monel woven-wire screens. Many thousands in use. Also flanged strainers, % in. to 5 in. Write for Bulletin SL20S. YARWAY EXPANSION JOINTS All-steel welded construction; light but strong. Chromium covered sliding sleeves. Cylinder guide and.stuffing box integral, assuring perfect alignment. In ternal limit stops. Gun-pakt and Glandpakt types: Gun-pakt (illustrated) has fixed glands fitted with screw guns which permit addition of plastic packing while joint is under pressure. Sizes 2 in. to 24 in., single end or double end, flanged or welding ends; 150, 300 and 400 lb pressures. Choice of leading utilities and industrial firms. Send for Bulle tin EJ-191S. 1561 Heating Systems.' |`"water Warren Webster & Company Pioneers of the Vacuum System of Steam ffeating: : Since 1888 Main Office and Factory: 1731 Federal St., Camden 5, New Jersey WEBSTER HEATING EQUIPMENT Webster Steam Heating Equipment: Radiator Valves Thermostatic Traps Float-and-Thermostatic Traps Double Service Valves Radiator Trap Attachments Boiler Return Traps and Vent Traps Boiler Protectors Dirt Strainers Metering Orifices Lift Fittings Expansion Joints Vacuum Breakers Chain Wheel, extended stem and lock- shield key Special Handles for Radi ator Valves Gauges Grease Traps Sight Glasses Hylo Vacuum Controllers Pressure Difference Controllers Time Switches Steam and Oil Separators Webster Process Steam Traps: Thermostatic Traps Float-and-Thermostatic Traps Dirt Strainers .- Webster Steam Heating Controls: Webster Moderator Systems Webster Main Steam Control Valves Webster Motorized Shut-Off Valves Webster Hot Water Heating Controls: Webster CF-3 Continuous Flow Control Webster Motorized Shut-Off Valves Webster M-INA Control Valves Webster Radiation Products: Webster Walvector, for Steam or Forced Hot Water Webster Type E Convectors, for Steam or Forced Hot Water Webster System Radiation, for Steam Webster Baseboard Heating Systems, for Forced Hot Water Webster-Nesbitt Unit Heaters for Steam or Hot Water Webster Gas Unit Heaters WEBSTER TRU-PERIMETER HEATING Webster Tru-Perimeter Heating uses Webster Baseboard, Webster Walvector, or a combination of both, to replace the heat at the perimeter where heat loss occurs. Heating elements are mounted close to the floor along outside walls, spreading the heat the entire length of the exposed walls. Webster Tru-Perimeter Heating warms the air within a room, warms the floors, and warms the inside surface of outside walls where a normal coolness occurs during the winter months. Gently mov ing wanned air is drawn to floor level and across the floor into the inlet opening of the radiation. Radiant heat rays strike the floor along the full length of the ex posed walls. Floors are warm and com fortable even with slab floor con struction. Heating Element Heating elements in Webster TruPerimeter Heating, either with Webster Baseboard or Webster Walvector, consist of copper tubing with aluminum fins con cealed behind a metal baseboard or light weight, sturdy and attractive metal en closure with grilled opening at the top. The enclosure eliminates the expense of tiimal steam installations. 1562 Warren Webster & Company Heating Systems Steam Hot Water concealing piping in furred wall spaces or expensive trenches. Where necessary, heating elements can be sleeved through any construction material without loss of structural strength, thus avoiding the need for piping through floors. Uniform Heating By spreading heat over the entire length of exposed wall, Webster TruPerimeter Heating provides the essen tials of' comfort heating. Uniform air temperatures from one corner of a room to the other are accompanied by remark ably close air temperature differences from floor to ceiling--usually less than two degrees. Warmed air rising from Webster Tru-Perimeter Heating stops downdrafts by blending the cooler air near windows into the warm air stream moving upward. Wall-to-tvaU application of Webster Walvector. Webster Baseboard Webster Tru-Perimeter Heating, using Webster Baseboard and forced hot water, offers basic advantages for new home heating or modernization of older residential heating. There is a minimum of piping, auxiliaries and controls, and the system takes less time to install. There are no radiators to rob floor and wall space, or interfere with freedom in decoration. Heat is clean and odorless, without the air baking caused by high heat concentrations. Wasteful over heating is avoided, and the system oper ates economically. All piping is acces sible, and there are no air ducts, supply and return pipe loops, or run-outs in basement. Ieometric view of Tru-Perimeter Forced Hot Water Webster Baseboard Heating in typical modern ranch house. Kitchen can be heated by Webster Walvector or Series E Convector (not shown). Note simplicity. larger amounts where needed to supple ment a Webster Baseboard installation. When used with low-pressure steam, Webster Walvector may be provided with tube-type orifices so that when any steam is delivered to the radiation it is delivered throughout the entire length. This makes it. possible to use the con tinuous flow control of the Webster Moderator System, with its assurance of continuous comfort heating and quick shut-off and quick heating-up character istics. For complete information on Webster Tru-Perimeter Heating, send for Bulletin B-1602 on Webster Baseboard Heating or Bulletin B-1551 on Webster Walvector. Webster Walvector Webster Tru-Perimeter Heating with Walvector provides the same advantages for larger installations, or for heat in Cutaway view showing design simplicity of Webster Tru-Perimeter Forced Hot Water Baseboard Heating. 1563 Warren Webster & Company Heating Systems Steam Unit Heaters WEBSTER-NESBITT UNIT HEATERS Manufactured by John J. Nesbitt, Inc., Philadelphia 36, Pa., and distributed solely through Warren Webster & Company, Camden, New. Jersey. Designed to circulate large volumes of air at comparatively low temperatures, assuring quick heating. Ratings of Webster-Nesbitt Unit Heaters are based on tests made in accordance with standard test code of Industrial Unit Heater Association and A.S.H.V.E. Fig. 1. Standard Propeller-Fan Type PROPELLER FAN UNIT HEATERS Designed to incorporate tour characteristics essential to both proper application and satisfactory performance: 1.) Selective range of sizes. Manufactured in nine sizes. Heating capacities from 34,700 to 338,000 Btu per hour. Air deliveries from 470 to 4800 cfm. 2.) Quiet Operation. All. fans have blades of exceptionally large areas and of a shape to impart a gradual acceleration to the air stream. Ample spacing is maintained between the fan and heating element. Motors are of sleeve bearing type equipped with isolators. 3.) Dur able lightweight Heating Elements. Extended fin-and-tube type, constructed of copper condensing tubes and plate-type aluminum fins. 4.) Modern Casing Design. Compact sus pended type. Pub. W-N 126.. GIANT BLOWER-FAN UNIT HEATERS Large capacitity unitB for: heating and/or ventilating, free delivery or static pressure, steam or hot water systems. Nine basic sizes, each with one of three standard steam coils, three distributing-tube coils, or with a single, two, three, or fourrow hot water coil. Air deliveries from 2000 to 28,000 cfm. Basic steam ratings, 83,000 to 1,735,000 Btu/hr. Hot water capacities from 50,000 to 2,460,000 Btu/hr, 1800 to 3400 fpm. Control may be STANDARD--periodic fan operation; THERM-ADJUST--continuous fan operation with thermo stat-controlled dampers; or VALVE-CONTROLLED--with thermostat controlling steam supply. Horizontal-suspended, wall, inverted or floor-mounted with wide choice of cowls, fans dampers, filters and other accessories. New Pub. W-N 135. LITTLE GIANT UNIT HEATERS Fig. 9 Blower-Fan Type Fig. 8 Dawn-Blots Type Adaptable to a wide variety of applications and field condi tions. Eight basic sizes, each with a choice of two (some units three) heating elements. The three smaller sizes are of the blow-through type, having lower outlet velocities generally intended for the lower mounting heights of commercial in stallations. These sizes in down-blow type only. The five larger models are of the draw-through type; produce the high discharge velocities necessary to blow long distances. These five available for either horizontal or vertical down-blow. Non-ferrous all-purpose heating elements designed for steam pressure up to 200 lb gauge, saturated, and sturdy casings of modern design. Heating capacities range from 28,500 to 510,000 Btu basic steam ratings. Pub. W-N 134. . SERIES "R" UNIT HEATERS A neat, furniture steel cabinet enclos ing a copper-tube, aluminum-fin heating element adaptable for steam or forced hot water systems; and two to five centrifugal fans belt-driven from an elec tric motor. A variable-pitch motor sheave permits low or high speed fan operation. Universal design offering wide flexibility and quiet operation. Available in four sizes. Air deliveries with standard drive range from 518 to 1890 cfm. Steam heating capacities from 158 to 588 EDR. Pub. W-N 133. 1564 t J Heating Systems * v.iies. Air The Dole Valve Company Main offices and Factory: 1933 Carroll Avenue, Chicago 12, 111. WATER MIXERS THE ALL STAR LINE AUTOMATIC REGISTERS AIR AND VACUUM VALVES "DOLE AUTOMATIC REGISTER" FOR FORCED WARM AIR HEATING SYSTEMS PROVIDES INDIVIDUAL ROOM TEMPERATURE CONTROL 1. Operates thermostatically from room air temperature. 2. Extremely Sensitive: Modulates output to meet heat requirements. 3. Completely self-contained; no wires to run--no bulbs to locate--simple to install. Replaces standard forced warm air registers. 4. Simple setting of the thermo-dial assures room temperature as desired-- corrects many unsatisfactory heating in stallations. Materially improves any forced warm air system. An automatic balancer. 5. A fully automatic zone control for every room. Dole Automatic Registers are available in two sizes and will tit the following stackhead openings: 10' will fit--10' x 4', 10' x 5', 10* x 6'. 12" will fit--12" x 4', 12' x 5", 12" x 6". With an adapter 12' will fit--14' x 4', 14" x 5", 14' x 6". An adapter is available for baseboard installation of these Controls. Temperature Selector Dial DOLE AIR AND VACUUM VALVES Dole No. SO Folly Automatic Hot Water Air Valve The Dole line covers every venting need on one pipe steam and hot water heating systems and offers a complete choice for every purpose. DOLE WATER MIXERS Dole Water Mixers provide safer, tem pered domestic hot water on all tankless beater and storage tank installations. Available in 3 sizes, }4 in., % in., and 1 in. 1565 III msfl- 4i Heating Systems valves The Fairbanks Company 393 Lafayette Street New York 3, N. Y. . Boston; Pittsburgh; Binghamton, N. Y.; Home, Georgia - ,, Dependable Service GUARANTEED From This Complete Line Of Bronze And Iron Body Valves Available From Your Local Distributor BRONZE GLOBE AND ANGLE VALVES Pressures--125 through 300 Lbs S.W.P. Ends--Screwed, Flanged, Solder, Brazed and Hose. Discs--Bronze: Renewable Composition; Nickel Alloy Semi-Plug Disc and Seat; Stainless Steel Semi- and Full Plug Disc and Seat. Needle Valves Radiator Valves LP--Gas Valves ' Fig V-Ol 160 Lb. SWP BRONZE GATE VALVES Pressures--125 through 300 Lbs S.W.P. Ends--Screwed, Flanged, Solder, Brazed and Hose. Stem Action-Rising with Solid or Split Wedges, Non Rising with Solid Wedges. , Bonnets--Screwed, Union, Bolted and O. S. & Y. Radiator Valves LP--Gas Valves Fig. 0250 ItSLb.SWP BRONZE CHECK VALVES Horizontal, Angle and Vertical Types--Swing and Lift Pressures--125 through 300 Lbs S.W.P. Ends--Screwed, Flanged, Solder and Brazed. Discs--Bronze, Renewable Composition, Rubber Faced. LP--Gas Valves IRON BODY GLOBE & ANGLE VALVES Bronze Mounted - Pressures--125 through 250 Lbs S.W.P. Ends--Screwed and Flanged Discs--Bronze, Renewable Composition, Nickel Alloy Semi-Plug Disc and Seat Bonnets--O. S. & Y. Automatic Stop and Check Valves Fig. 040$ Its Lb. SWP IRON BODY GATE VALVES Bronze Mounted and All Iron Pressures--125 through 250 Lbs S.W.P. Ends--Screwed, Flanged and Hub Stem Action--Rising, Non-Rising and Quick Opening Bonnets--Screwed, U-Bolt, Bolted & O. S, & Y. Underwriters' and AWWA Approved Valves Fig. 0702 . Its Lb. SWP IRON BODY SWING CHECK VALVES Horizontal--Bronze Mounted Pressures--125 through 250 Lbs. S.W.P. Ends--Screwed, Flanged and Hub Discs--Bronze, Bronze Faced and Rubber or Leather Faced 1566 / Heating Systems Valves and Fittings H B Wammond rass orks HAMMOND, INDIANA HAMMOND VALVES--A complete line of packed type radiator valves for steam, gravity and circulator hot water systems--balancing elbows and fittings for forced hot water heating systems and floors, ceiling, and wall radiant panel heating. Hammond Circulator Valves, Balancing Elbows and Fittings for Forced Hot Water Heating Systems. For Iron Pipe and Copper Tubing. These valves can be furnished in any combination of copper to iron, copper to copper, iron to copper, etc. Service Recommendations No. 201-- Circulator-Male Union and Sweat Con nection. Provides a "nearly tight" shut-off when closed and full flow when opened. A quarter turn of the handle permits the valve to be opened smoothly and easily. No. 202--Circulator-Male Union and Sweat Connection. For forced hot water systems only. Particularly suited for use with concealed or "convector type" radiators, which installation frequently requires a valve for the lower vertical radiator tapping. A quarter turn of the handle permits the valve to be opened smoothly and easily. No. 308--Copper to copper balancing ells for panel heating. No. 301--Balancing Elbow-Male Union Hammond Radiator Valves and Elbows : Systems. For Iron Pipe and Copper Tubi and Female Thread. No orifices or adap tors are needed when this elbow is used. The external adjustment allows for ad justing and readjusting while the system is in operation and eliminates inconveni ence of draining. No. 302--Union Elbow-Male Union with Sweat Connection. Can be used on cop per tubing gravity jobs and also where the supply valve is adjusted, but we do not recommend adjusting any system at the inlet. No. 303--Balancing Fitting-Male Union and Female Thread. For concealed or convector type radiators. No. 30S--Copper to copper balancing ells for panel heating. No 100--Steam Angle. Can also be used for vapor. Steam and Gravity Hot Water Heating No. 101--Steam Corner. Same as No. 100. Specify whether right or left hand wanted. Valve illustrated is left hand. No. 102--Gate Union. For hot water installations and steam or vapor heat ings systems. Especially suitable for use with unit heaters; ideal for general shut-off valve service at other points throughout heating systems including boilers and hot water heaters. Specify when ordering for hot water system, as such valves are furnished with a small hole drilled through the disc to provide for slow circulation when valve is closed. No. 105--Convector Single Union Gate. Same as No. 102, but single union does not permit removal of radiator while system is in operation. No. 108--Convector Female Union Steam Angle. Same as No. 100, but should only be used Tot convector radiators equipped with inside leg tappings. The female union eliminates the necessity for exact roughing in measurements to tapping. Variation of the nipple inside leg will allow for adjustment. Shipped with bonnet loose to facilitate installation. No. 300--Union Elbow--For gravity hot water heating installations. No. 104--Double union gate for convec tor radiators only. See Hammond Catalog for complete line of valves. Warehouse stocks located in 29 cities throughout the United States. 1567 Heating Systems vairea Jenkins Bros. 100 Park Avenue, New York 17, N. Y. BaiDGEPOBTjCoNN.; Boston, Philadelphia, Chicago, San Fhancisco, Atlanta -- , LOOK FOR THIS DIAMOND MARK Leading Supply Houses Everywhere Stock Jenkins Valves FOR EVERY NEED JENKINS CATALOG LISTS OVER 500 VALVES Consult Jenkins Catalog for complete details on more than 500 different valves that cover practically all industrial plumbing and heating, and engineering requirements. Below is a brief list. All-Iron Valves,--globe, angle, gate; Angle Valves,--bronze, steel, and iron body with bronze mounting or trimming. Blow-Off or Y Valves,--hronze and iron. Electrically Operated Valves, Gates, Globes, Angles, Fire Line Valves; Floor Stands; Foot Valves for gasoline service. Gate Valves,--bronze, iron, steel; with solid wedge or double disc parallel seats; with removable bonnet and renewable bushing. Globe Valves.--bronze, iron and steel; one piece and union bonnets; renewable and integral seats; rubber composition or metal discs and plugs. Horizontal Check Valves.--bronze, iron and steel; Hose Valves; Indicator Posts; Lock Shield Valves. Needle Valves; Non-Return Valves; Quick-Opening; Self-Closing Valves. Radiator Valves; Rapid Action Valves; Regrinding Valves; bronze and iron body with bronze trimming; renewable plug seats and bevel seats of a special nickel alloy in globe, angle, check and swing check patterns. Selclo Valves; Stop and Check Valves,-- combination or automatic equalizing; Swing Check Valves,--bronze, iron and steel. Stainless Steel Valves,--globe, angle, gate and check. Underwriters' Pattern Valves,--check and gate; Whistle Valves; Waterworks Valves. Insulation af cooling April Showers Company, Inc. 4126 Eighth Street, N.W. Washington 11, D. C. AT E NT E D AUTOMATIC ROOF COOI-ING (Tiade Marti Heg. V. S. Pat. OS.) AUTOMATIC EVAPORATIVE ROOF COOLING Distributors and Dealers in Principal Cities ROOF COOLING Spray Method GREATER COMFORT AND BETTER WORKING EFFICIENCY WITH ECONOMICALLY WATER COOLED ROOFS The advantages in preventing Solar Infiltration by SURFACE COOLING, are today widely recognized by economyminded, efficiency-wise Architects, Air Conditioning Engineers and Top Man agement. The APRIL SHOWERS System is fully automatic. The Sun operates it. Re quires very little water and City water, under normal city pressure, is usually adequate. No runoff. Installation and Maintenance Costs are low. Only finest materials are used. Precision workman ship throughout. APRIL SHOWERS are now In use on 18,000,000,000 sq ft of Industrial Roofs A few of these installations are:--Country Life Press, Garden City, L. I., Hallicrafters Co., Chicago, 111., Lilly Tulip Cup Co., plant (Westinghouse air condi tioned), Augusta, Ga., Aerojet Engineer ing Corp., Azuza, Cal., Westinghouse Electric Co., Hyde Park, Mass., Gen eral Electric Corp., Providence. R.I., Bulova Watch Co., Providence. R. I. Recent installations include:--Interna tional Business Machines, Vestal, N. Y 53.000 sq ft; Bell Air Craft Corp., Buffalo, 51.000 sq ft; Lily Tulip Cup Corp., Springfield, Mo., 279,500 sq ft; Westing house Electric and Mfg. Corp., Balti more ; Eastman Kodak Company, Kodak Pk., N. Y., 156,000 sq ft; Dixie Cup Co., Easton, Pa., 25,800 sq ft Installations with air conditioning re duces air conditioning tonnage from 25 per cent to 40 per cent for some plants. In addition, -the Federal Government has over one million square feet of April Showers installations. Among them is the 500,000 sq ft roof of the U. S. Naval Ordnance building in Indianapolis, Ind. APRIL SHOWERS also works efficiently in conjunction with any True air condi tion system by reducing (in cases where requirements necessitate the use of an exorbitant tonnage) the size of the True syBtem necessary to give the required temperatures for Comfort and Efficient Working Conditions, At the same time, it helps by reducing operating and main tenance costs. Moreover, it adds years of life to the roof itself by preventing the sun from more speedily evaporating the protective roof-coating oils. Consider APRIL SHOWERS for your next project or remodeling job. We will be pleased to work with you on any problems that may arise. NOTICE:-- Our newly developed Spray Head, for use on Dwellings with flat or peaked roofs, are now in distribution, APRIL SHOWERS controlled roof ( ooling is protected by U.S. Patents. Write for Descriptive Literature :Yo obligation for Estimates A FEW CHOICE DEALERSHIPS STILL AVAILABLE . . . WRITE 1569 Insulation Anchors Miracle Adhesives Corporation Devices, Inc. (Affiliate) Manufacturer of Miracle Surface Anchors 214 East 53 St., New York 22, N. Y. . Representatives in all Principal Cities and in Canada MIRACLE SURFACE ANCHOR METHOD CUTS COSTS... SAVES TIME Miracle Surface Anchors consist of per forated metal plates 2 in. x 2 in. or 2% in. x 2% in.--to the center of each is welded ' a nail, bolt, spindle, prong, or threaded stud. These Anchors are zinc and diehromate finish to resist corrosion. (See Fig ures 2, 3 and 6.) Fig, J: Allocking Corkboard tiith Miracle Sjrirufk Anchors to Ducts Fig. t: Miracle Spindle Anchor and Wosfufr Fig. 3: Miracle Curved Spindle Anohor for Comes surface of corrugated metal Miracle Spindle Anchors--When attached to ducts, walls, ceilings, ship hulls, deck heads, etc., will firmly support various types of insulation, such as Cork, Batt and Fiber Glass, by impaling the insula tion (and wire mesh, if any) on the spindle (Fig. 1). Self clinching washers to fit over the spindles are available, (Fig- 2). Spindle Anchors are also made on a curved plate for attaching to convex sur face of corrugated metal (Fig. 3). Miracle Pronged Anchors--When at tached to ducts, walls, ceilings, etc., sup port foam glass and other types of block insulation. Pronged Anchors are set be tween rows of block insulation and when the latter is to be left exposed, prongs are bent in reverse direction over the blocks. When wire mesh is to be added for mastic finish, one prong of each An chor is bent over the block insulation-- the other prong penetrating the wire mesh and then bent over it before apply ing mastic (Figures 4 and 7.) Fig. 7. Ceiling construction uith Miracle Pronged An* chore .' Advantages: 1. Cut costs because of faster application. 2. No wiring--no metal corner beads-- no preliminary spotting of ducts or insu lation with mastic necessary. 3. Ideal for cumbersome installations such as fan housings and similar equip ment. MIRACLE "Z" CLIPS Miracle "Z" Clips consist of 2 in. x 2 in. or 2 in. x 4 in. perforated 20 gauge steel. "Z" Clips, because of their hinged con struction allow for any irregularities in the surface to which they are bonded. "Z" Clips provide an effective and eco nomical means of attaching wallboard, plasterboard, or insulation board to the inside of exterior walls when an- air space is required between the wall and the board. The "Z" Clip method completely eliminates necessity for studs or furring strip (Fig. 8, 9 and 10). Fig. 8: Cal. No.--Z-SS Dimensions-- in. x in. Fig. 9: Cat. No.-Z-H Dimensions-- in. x 4 in. Fig. JO: Vertical vail section illustrating Miracle "Z" Clips in position 10. Fig. 1: Wall construction xcith MiracLe Pronged Anchors Fig. 6: Miracle Pronged A nchors are also used for sup porting small cables, tubing, air lines, etc. Fig. 6: Miracle Pronged Anchor Adhesives:--For Anchor installations use Miracle Anchor Adhesive for temper atures minus 20 F to plus 250 F or Mira cle RT-1000 for temperatures 250 F to 450 F. For cold storage or extra low tem peratures use Miracle NP-153 or RT-1000. 1570 Insulation American Gilsonite Company Salt Lake City, Utah An affiliate of Barber Oil Corporation & Standard Oil Company of California Representatives in principal cities. SULATE TRIPLE-ZONE INSULATION Qilsulate is a unique solidified hydro carbon of high resin content which is poured directly around hot underground pipes for insulation and corrosion- protection. ' GENERAL DATA 1. Low cost per installed linear foot 2. Easy-to-use: pour . . . tamp . . . backfill--normal pipe heat (up to 520F) does the rest 3. Fuses itself in hours into 3 zones of permanent protection for the life time of the pipe against all com monly-encountered buried-line con ditions such as acids, alkalies, roots, water, and corrosion 4. Tested and proved in actual use in hundreds of new construction and replacement installations across the country 5.. Can be used under all multiple-pipe and cramped space conditions (see illus. below) 6. Needs no sleeves or mechanical sheaths to protect it 7. Needs no mixing or special handling 8. Can't be punctured, obviating need to remove rocks from backfill * 9. Needs only normal pipe spacing; steam and condensate lines can run side by side 10. Pipe expands and contracts within Gilsulate structure 11. Makes repairs to the pipe quick and easy GRADES AND TEMPERATURE RANGES Type A........................ 220F to 310F Type B....................... ......... 300F to 385F Type C....................... ......... 385F to 520F TRENCH SIZE 4 in. to 16 in. wider than pipe diameter, 18 in. deep EFFICIENCY Heat loss 8-12 per cent of bare-pipe Inert to ordinary acids and alkalies found in soil, excellent dielectric For further data or information, write; American Gilsonite Co., 134 W. Broadway, Salt Lake City 1, Utah, or 1145 E. Jersey St., Elizabeth 4, N. J. . 1571 i Insulation Conduit Durant Insulated Pipe Company Demeter Street off Bay Road Palo Alto, California Eastern Division: Durant International Corporation Willlamstown, New Jersey REPRESENTATIVES IN PRINCIPAL CITIES DURANT Pre-Sealed INSULATED PIPE APPLICATION D. I. P. is used in underground and weather-exposed locations for conveyance of steam (1 to 1000 psi), hot water, and refrigerants. It is used for new lines, for replace ment of worn-out lines, or for use in an existing tunnel where waterproofing is re quired. It is fabricated, in standard lengths, in pipe sizes up to 24 in. Larger sizes available on order. / SPECIAL FEATURES AND FACTS ON D. I. P. D. I. P. is a pre-sealed insulated conduit that does not depend on a metal jacket for protection from moisture, leakage and corrosion. A 1 in. layer of highmelting-point, non-porous asphalt is the waterproofing protection. By design, Durant's Patented Support ing Ring allows asphalt to flow through openings during fabrication to com pletely encase the ring. Water or mois ture cannot pass through D. I. P. casing to the insulation or pipe. Durant's Patented Insulated Anchor eliminates contact between anchor plate and pipe; reduces heat loss; provides electrical as well as thermostatic insula tion, and eliminates corrosive electro lytic action. Use of D. I. P. affords many other ad vantages--such as low cost installation, for the Durant field joint can be made swiftly and easily. D. I. P. does not re quire external casing-welding; nor does it require concrete tunnels, slabs, rollers, supports, drains or additional protection for superimposed loads--such as under roadways or railroad tracks. D. I. P. systems have an exceptionally long service life. Many a D. I. P. system of over 25 years' service is functioning efficiently today. Durant Insulated Pipe Company Insulation * Conduit SFACi* AND tOAD WAStMO Pin WITH INSULATION t SUPPORTING RINGS IN PLACE DESCRIPTION AND CONSTRUCTION D. I. P. is a prefabricated, factory-built, insulated and waterproofed pipe. It is constructed by first encasing pipe (steel, wrought iron, copper, brass or alloys) in Unibestos, molded 85 per cent magnesia, Spongefelt, or other insulation, suffi ciently thick to insure insulation surface temperature not above 150 F. Loose-pack material is not used. Over both pipe and insulation, patented Durant supporting rings are slipped, not more than 36 in. apart. A heavy gage sheet-metal casing, circular in form, is placed around the supporting rings, al lowing a 1 in. (minimum) space between insulation and casing. This space is filled with a high-melting-point, non-porous asphalt. Special methods are used during pouring to obtain thorough distribution of asphalt, eliminate pockets and main tain uniform thickness. D. I. P. conduits are circular in cross-section on all single line units. Multiple pipe systems are either circular or oval, depending on the pipe sizes involved. A variety of standard, prefabricated ac cessory items are available -such as tees, ells, expansion loops, anchors, pipe sup ports, and other items which may be required for completely prefabricated piping systems. Fabrication is made in accordance with shop drawings which must be approved by engineer and con tractor prior to shop fabrication. Units are shipped, marked for assembly in the field, and are accompanied by all materials and instructions for the mak ing of field joints. Durant's engineering staff and representa tives are at your service. Write for recom mendations, estimates, or new Catalog DSS. The packed type end cap is used where conduit terminates in a space such as a manhole or yardbox, or other location where submersion in water can occur and where piping is not anchored at terminal. . This type is constructed of a compression coupling packed with a high temperature asbestos gasket. The coupling bolts and sleeve are welded to a heavy gage section of outer casing. This type end cap per mits the pipe to expand and still remain water tight. 1573 ~T-m Insulation Snd"ad fFhcrm-O-Ui/c, H. W. Porter & Co., Inc. 817-G Frelinghuysen Ave., Newark 5, New Jersey Permanent Protection and REID HAYDEN, INC. HpataTj" Underground Baltimore> Md Richmond, Va. Charlotte, N.C. Also sold and installed by Johns-Manville Construction Units in all principal cities. The Advantages Offered by Therm-O- With wet insulation, efficiency drops Tile are: drastically, and unless the conduit is built on an unyielding foundation there 1--Higher efficiency PERMANENTLY. may be sagging and collection of water in - A dry conduit PERMANENTLY. pockets. Insulation always DRY. Drainage Channel. The Therm-O-Tile 2--Sealing is positive throughout. In ternal drainage assures dry, efficient . insulation. 3--An arched construction that is stronger than required by ASTM. concrete base contains a drainage chan nel--see photograph--which carries off all water that may enter the conduit from any source, thus keeping the in sulation PERMANENTLY dry. Drain age is entirely internal and ample to keep I; t:.` 4--"Spread-Footing" foundation. The the pipe space always dry. Open to "sidewalk" makes installation easier. thorough inspection at any time at man 5--Surrounded by sealed air. holes. "Spread-Footing" Foundation. The 6--All loads are taken directly by an foundation base of Therm-O-Tile is a unyielding base. thick concrete slab poured directly in the 7--The correct slope is PERMANENT, trench bottom. This positively prevents hence no condensation pockets. settling and sagging. The original sur- 8--PERMANENCE assures maximum economy. Lowest ultimate cost. THERM-O-TILE STEAM PATENTED , CONDUIT SYSTEMS Therm-O-Tile assembly view with filler type insula tion. For a view with sectional pipe covering see the 1958 QUIDS. Note the channel drain which makes Jot "permanent protection." All leading heating and ventilating engineers have known PERMANENT Therm-O-Tile for many yeArs, but we wish, again, to emphasize the importance of "Permanent protection." It is easy to provide TEMPORARY protection and insulation under ground. Threads and joints don't fail immediately. Founda tions don't sag immediately. But unless the job is properly done INITIALLY it won't be long before water seeps in and ruins the insulation. veyor's slope is PERMANENTLY held hence condensate pockets cannot form. Steel reinforced or placed on piles when installed over filled or boggy ground to insure PERMANENCY. 27 Conduit Sections. Top and base sec tions of the Therm-O-Tile envelope are' made in a number of different sizes. 27 conduit sections are thus made available. For complete data ask for Thenno-O- Tile Bulletin. Competes in Original Cost. In spite of the superior features obtained in Therm O-Tile, it is nevertheless competitive in total first cost. Engineers -- Contractors -- Manufac turers. Write, phone, or wire the nearest Porter-Hayden or Johns-Manville Tech nical Service Unit for estimates, recoin - i ________ _ mendations, and complete specifications Therm-O-Tile Conduct with ThenmO-TOe Conduit with for the conduit and insulation on any Filler Type Insulation. Sectional Pipe Covering. underground pipe line project. . 1574 Insulation Conduit and Underground The Ric-wiL Company Prefabricated Insulated Piping Systems UNDERGROUND or OVERHEAD Barberton, Ohio Representatives in Principal Cities Ric-wiL Systems for central heating and process piping are engineered and insulated to specific project requirements for efficient distribution . of steam, hot or refrigerated liquids and gases. Hel-Cor Insulated Pipe Units ... Single or Multiple Pipes Prefabricated in 21 ft lengths with any specified combination of pipes and insulation. 16 gage helically-corrugated, hot-dip gal vanized metal housing, protected with asphalt coating. Hel-Cor Uniline--For Oil or Process Liquids Similar to standard units except pipes are nested inside a laminated asbestos insulation liner--insulated from the exte rior but not from each other. Designed for oil and process liquids. ' Ric-wiL Cast Iron Insulated Pipe Units Factory prefabricated 18 ft 6 in. lengths. Pipe and insulation housed in heavy-duty cast iron conduit. Insulation any type or thickness to meet job requirements. Hel-Cor Underground Systems Standard 21 ft prefabricated sections for efficient field installation. Single or multiple pipe Hel-Cor Units or Hel-Cor Uniline Insulated Pipe Units can be used underground or overhead. Hel-Cor Overhead Systems Prefabricated 21 ft pipe units for straight runs. Elbows, tees, anchor units and expansion loops finished at factory and delivered to job site with joint materials for simple assembly. Cast Iron Underground Systems For underground insulated piping sys tems where permanency and thoroughly tight joints are required. Prefabricated for easy field assembly, complete with accessories--expansion loops or joints, etc. For full descriptive literature and technical information on Ric-wiL prod ucts and services, call or write the RicwiL office nearest you, or the Ric-wiL Company in Barberton, Ohio 1575 it Insulation Conduit aad Underground Division Zonolite Company 135 S. LaSalle St. Chicago 3, 111. UNDERGROUND PIPE INSULATION Z-CRETE* is a Lightweight Insulating Concrete which is poured directly and monolithically around heated under ground piping. , Z-CRETE insulation serves as a mono lithic, jointless insulating filler around pipes. A curing and waterproofing mem brane completes the installation. GENERAL DATA The Z-CRETE system of underground insulation is a field fabrication adaptable to any size, number or arrangement of pipes. Six inches of insulation is ordinarily used on the outside of all pipes. A minimum of four inches is economical spacing be tween piping. Z-CRETE installations have no joints to leak heat or collect water--they are as permanent as the earth itself. Anchors, guides and expansion devices (except loops) are the same as used in any other system. The curing membrane provides external water protection and imparts a tensile strength to the conduit. - - TYPICAL Z-CRETE CONDUITS Commonly used designs of Z-CRETE are shown above. The single pipe and double pipe conduit consist of a structural concrete pad, .pre-cast Z-CRETE support blocks on which the pipes rest, a pour of Z-CRETE insulating concrete and a curing and waterproofing membrane. The multiple pipe conduit at the right has a second pre-cast support for the upper group of pipes. . REINSULATION OF EXISTING CONDUITS The ruinous effect of water on steel pipe and insulation is well known. Z-CRETE insulation restricts moisture, keeps the conduit dry. Inorganic Z-CRETE con crete naturally resists deterioration. Many existing hollow or Box Type Con duits may be reinsulated by pumping them full of Z-CRETE. The mass of water resistant Z-CRETE restricts the movement of moisture, so special drain age provisions are not ordinarily re quired. Z-CRETE is sold and installed by licensed applicators of Zonolite Com pany under U. S. Patent No. 2355966-- Canadian Patent No. 439356. There is an applicator near you. For further data or information, write Dept. HV-4. Z-Ciete is a registered trade mark of Zonolite Company. 1576 Insulation Glass Bfecks Owens-Illinois GENERAL OFFICES TOLEDO I, OHIO GLASS BLOCK Owens-Illinois Glass Block Give Better Control of Interior Conditions . What they are--Owens-Illinois Glass Blocks are hollow, hermetically sealed units containing a partial vacuum. Prop erly used they aid control of interior conditions to a point where initial and operating costs of heating or cooling equipment are reduced. Conductivity Coefficient of Heat Transmission--The "U" factors for panels of Owens-Illinois Glass Block are as follows: . Nominal Block Size . "IT* 6*8d. 0.60 Vtq. 0.56 8* (with glass fiber screen) 0.48 See page 197 of this GUIDE for complete data. The "U" factor for a panel of 8 in. Glass Block is just one-half of that for single glazing. The reason lies in the two heavy glass surfaces separated by partially evacuated and hermetically sealed dead air space. Surface Condensation Because of the low over-all, air-to-air heat transfer, the exterior air tempera ture which will produce condensation oh a Glass Block panel is much lower than that for ordinary, windows. This per mits higher humidities where needed, for winter air conditioning for both com fort and industrial processes. Being glass, they cannot rust, rot, nor corrode . . . are not subject to deterioration caused by moisture. air and vapor leakage are minimized. Natural ventilation requirements can be met by installing windows, either inset into the panels or directly below or above the panels. Solar Heat Gain A comparative test showed over two times as much solar heat through single glazed steel sash as through Glass Block panels. However, as with sash, Glass Block transmit less solar heat when properly oriented and shaded. Com plete instantaneous solar heat gain data for all block designs and for all expo sures are given on pages 292 and 293 of this "GUIDE." Design, Sizes, Erection Owens-Illinois Glass Block are made in a variety of face designs that distribute light and limit sight in varying degrees. They are made in three standard sizes, 6x6, 8 x 8, 12 x 12 in. Actually each of these dimensions is a quarter of an inch less to allow for mortar joint. All blocks have a standard thickness of 3Jfj in. Complete technical data, description, and details will be gladly sent. Write Glass Block Division, Owens-Illinois Glass Company, Dept. HV, Box 1035, Toledo 1, Ohio. Infiltration A panel of Glass Block provides a wall of glass and mortar which seals the building against infiltration. Dust, drafts, and Illustration* above show how Glass Block effectively con trols daylight. To the left you see what happens when light beams strike an ordinary window. To the right, notice how the built-in prisms in Owens-Illinois Glass Block No. 363 throw light UP, and spread it. .Result i* even, diffused light over all parts of the room. 1577 Insulation Glass PITTSBURGH CORNING CORPORATION Dept. AW4, One Gateway Center, Pittsburgh 22, Pennsylvania THERMAL INSULATION PC Glass Blocks allow economical use of large glass daylighting areas, reduce heat loss in cold weather and heat gain in warm weather because each PC Block contains a sealed-in dead-air space that is an effective retardant to heat trans fer. See Section C, Table 20, Page 197 of this Guide. SURFACE CONDENSATION Because of their high insulating value, condensation will not start forming on the room side of PC Glass Block panels until outside air has reached a tempera ture much lower than that necessary to produce condensation on single-glazed windows. The accompanying chart shows at what temperatures condensa tion will form. Note that (LX) and SKYTROL blocks--in which a fibrous glass screen creates a double cavity-- provide maximum insulation value. considerable advantage in buildings that are properly air-conditioned, but does not eliminate the need for adequate ventilation or shading in non-air-con ditioned rooms. For data on solar heat gain through PC Glass Blocks, see Tables 19 through 23 in Chapter 13. Types listed are the following PC patterns: Type I--Argus, Argus Parallel Flutes, Decora, Vue Type I /--Bristol 65 Type 111--Soft-Lite* Bristol 65 LX " Type IVA--Soft-Lite* Essex B 55 Type V--Prism A 55, Soft-Lite* Prism B 65 * Registered trademark . PC GLASS BLOCKS AID AIR-CONDITIONING The chief aims of air-conditioning-- temperature control, humidity control and cleansing of airfare aided by the use of PC Glass Blocks. Heat loss is less in winter--heat gain is less in sum mer. Solar heat transmission and radia tion are significantly reduced. Dirt, drafts and moisture cannot filter in, for each panel is a tightly sealed unit. PATTERNS SIZES INSTALLATION Outdoor temperature required to produce condensa tion on the room side surface of PC Glass Block panels. SOLAR HEAT GAIN The use of glass blocks for light-trans mitting areas results in a marked reduc tion in solar heat gain as compared with ordinary windows. This factor is of PC Glass Blocks are available in decora tive and functional patterns--the latter designed for control of transmitted day light and solar radiation. They are made in three sizes: 6 in:, 8 in., and 12 in. square. All are 3% in. thick. Usually they are laid up in panels with 14 in. mortar joints. Any mason can install PC Glass Blocks; no special tools are required. Insulated skylights that elimi nate many of the problems of ordinary skylights can be constructed using PC SKYTROL blocks. For complete in formation, write Pittsburgh Corning Corporation, One Gateway Center, Pittsburgh 22, Pennsylvania. . 1578 Insulation G'ass PITTSBURGH CORNING CORPORATION PITTSBURGH Department S-4, One Gateway Center, Pittsburgh 22, Pa. the cellular glass Insulation FOAMGLAS ... it stays dry! What FOAMGLAS is FOAMGLAS is an entirely unique thermal insulation. Its light-weight, strong, rigid structure provides the combination of the two essentials for efficient, long-lasting insulating per formance. . .FOAMGLAS is completely inorganic and has a closed cellular . structure. It is made of glass, expanded about fifteen times into minute, non connecting, hermetically sealed cells. This sealed cellular structure makes FOAMGLAS water-proof and vapor- proof, preventing moisture absorption which impairs greatly the effectiveness of many insulations. Being inorganic, FOAMGLAS is fireproof, rot-proof and vermin-proof. These inherent characteristics have For Building Roofs, Ceilings, Walls and Floors. At iPtnsion-Sofem, FOAMGLAS' high strength permitted insulating parking deck-roof of Sears Roe buck's air conditioned store. In your building, mois ture-proofFOAMGLAS insulation can help maintain air conditioning system efficiency. enabled FOAMGLAS users to benefit from its long-lasting, constantly-high insulating performance. That is why FOAMGLAS is very rapidly gaining recognition as the ideal insulation for roofs, ceilings, walls, and floors of all kinds of buildings, as well as hot and cold piping, tanks and other equipment. How FOAMGLAS can benefit you: Properties Benefits Absorption 0 Moisturereduces insula tion effectiveness and life. FOAMGLAS stays dry, m&intain- . ing constant insulat ing value. Acid Re- Impervious to No deterioration of in sistence common sulation: prevents acids and corrosion of piping acid fumes and equipment. Combusti- Incombustible Protects from fire bility hazards. _ Compres- 100 lbs/sq in Offers unusually high sive strength for wide Strength variety of structural and load bearing applications. Hygro- No increase in FOAMGLAS is its own scopidty weight in 246 vapor barrier, days in air at 90% relative humidity _ . Density 9 lbs/cu ft Lightweight, easy to (ave.) handle and install. Thermal Conduc- tivity(k) At 50 F 0.38 Btu/hr/sq Excellent insulating ft/*F/in value that remains constant. For Ducts. Light-weight blocks of FOAMGLAS were easily applied to these metal air conditioning ducts at the Moses H. Cone Memorial Hospital, Greensboro, North Coroltna.yik For Piping. FOAMGLAS pipe insulatwn (available for up to $6 in. pipe size) was applied on this welded pipe carrying cold water for ike system air conditioning Pittsburgh's new Galeu-ay Center skyscrapers. For full technical information, please write for our new catalogs indicating which of the above uses of FOAMGLAS you are most interested in. Address Dept. S-4> Pittsburgh Coming Corporation, One Gateway Center, Pittsburgh 22, Pa. 1579 Insulation Air Ducts The Philip Carey Mfg. Company Lockland, Cincinnati. IS, Ohio PRODUCTS District Offices In All Principal Cities CAREYDUCT is recommended wher ever quietness, ease of installation, fire safety, fume resistance and good appear ance are desirable or essential. Widely used in air conditioning systems. Careyduct has proven itself on some of the largest governmental, industrial and commercial installations in the country. Write for engineering performance and installation data. ACOUSTICAL. Careyduct is a natural sound absorber and non-conductor of sound. Quiets fan noise; won't pick up and "telegraph" other outside noises. FIREPROOF. Being 100 per cent as bestos construction Careyduct won't smoulder or burn. Approved by Under writers' Laboratories, Inc. INSULATED. High-efficiency insula tion assures delivery of hot or cold con ditioned air to outlets with minimum change in temperature.' GOOD LOOKING. Surfaces are smooth and free from unsightly raised seams or joints. No stiffeners or braces. Blends well with modern interiors. AIRTIGHT. Won't "breathe" or vi brate at high velocities. Slipjoint con 6 TYPES OF CAREYDUCT struction prevents leakage. Insulated and Acoustical (I. & A.) Type. Built of asbestos sheets with ah inner SAVES SPACE. Being 40 per cent to SO per cent quieter than ordinary duct, Careyduct handles higher velocities, core and an' outer jacket. Combines duct, insulation and acoustical treat ment into one unit. permitting the use of smaller sized ducts. Flrefoll Panel (K.D.F.) Type. Fabri cated from Firefoil and shipped knocked * EASY TO INSTALL. Prefabricated down ready for assembly. For high tem Careyduct units are easy to install-- perature work. . particularly in tight places. Simple low cost fittings can be made in the shop or on the job.* Acid and Fume (A. & F.) Type. Built of asbestos sheets laminated together and treated for resistance to acids and alka * Installation under jurisdiction of International Sheet Metal Workers, A. F. of L. ' lies. Ideal for laboratories or industrial work. 1580 Insulation Air Ducts Pipe The Philip Carey Mfg. Company Lockland, Cincinnati 15, Ohio District Offices In All Principal Cities PRODUCTS CAREYCEL FOR AIR DUCTS Uses: A fireproof, low cost, high effi ciency asbestos board for insulating ducts and all types of air conditioning equipment. Use 1 inch thickness up to 85 F air temp and 80 per cent relative humidity. Recommendations for more severe conditions on request. Description: Composed of 12 to 14 laminations of indented (not corrugated) . asbestos felt per inch of thickness. Weight: approximately 1% lb per board foot. Sheet Size: 36 in. x 36 in., or cut to order. Blocks: 6 in. x 36 in. Thick ness: % in. up. CAREY IMPERVO FOR COLD PIPES Uses: A high efficiency insulation for cold or ice water pipes--keeps the water cold and prevents sweating. Double % inch thickness recommended for ice water pipes. Description: Laminated- insulating, felt with waterproof liner and jacket. 36 in. long in in., % in., double % in. and double % in. thick sections, finished with cotton duck jackets and bands. CAREYCEL FOR HEATING SYSTEMS CAREY PROTECTO TO PREVENT FREEZING Uses: Pipe coverings and blocks for pipes, boilers, ovens and other appara tus where the temperature doesn't exceed 300 F. Use 1 inch thickness for temperatures up to 300 F. Description: Pipe covering sections 36 in. long by 1 in., l]4 and 2 in. thick, finished with cotton duck jacket and bands. Blocks: 6 in. x 36 in. Sheets: 36 in. x 36 in., or cut to order. Thick ness: in. up. Uses: Designed especially to reduce the danger of freezing of exposed water pipes. Description: Consists of two inner layers of hair felt, a waterproof felt liner and an outer layer of insulating felt (wool felt). For severe conditions-- exposure down to 0 F--use two-inch thickness. 36 in. long sections with cot ton duck jacket and bands. Standard thickness--approximately 1% in 1581 Insulation Duct MOOLITE -- GLASS fIBIR ~ - - - INSUlrATt NG'WOOt GLASS FIBERS inc. 1810 Madison Ave., Toledo 2, Ohio Sales Offices and Distributors in Principal Cities MICROLITE is a low density, resilient, glass fiber insulating material with high thermal efficiency and sound absorption characteristics. It is made by the ELEC TRONIC-EXTRUSION PROCESS, de veloped, patented and used exclusively by Glass Fibers Inc. Application: Its light weight, flexibility ' and resilience make it easy to handle in large sections, easy to place properly and easy to fasten securely by modern meth ods. Microlite is simple to cut with a knife or shears, and can be bent around curved surfaces and easily fitted in irreg ular areas. In addition, this springy, airy insulating material is compressed ap proximately 4-to-l as it comes off the production line. The compactly wrapped rolls take up little storage space in fac tory warehouses and busy cutting-fabri cating rooms. Properties: Composed of minute glass fibers of consistent uniformity, bonded together in blanket form, Microlite re sists fire, corrosion, vibration settling and effects of humidity. Glass fibers are inorganic; they provide no sustenance for fungus or bacteria, and no food for rodents or insects. Inch for inch, Micro lite is one of the most effective of all insulating materials, as shown below. Densities: 3^, 1 lb, lb, and 2 lbs per cu ft. Widths: 18, 24 , 36, 48 and 72 in. Thickness: %, 1, 1H, 2 and 3 in. Lengths: 200 ft for and % in. thick. 100 ft for thicknesses more than % in. See how snugly Microlite fits into tight areas. That's because it's so resilient and compressible. Facings: Microlite is available with vapor barrier facing materials, applied to order. They may be made of foil, re flective coated paper, vinyl film and rein forced or unreinforced papers. THERMAL CONDUCTIVITY AT VARIOUS MEAN TEMPERATURES AND DENSITIES Mean Temperature, degF *"k" value Type B-305 (.5 Ibs/cu ft) ' "k" value Type B-310 (1.0 Ibs/cu ft) 50* 75 100" 150" 200 250" 300" .25 .26 .28 .33 .38 .45 .52 .20 .21 .23 .27 .31 .36 .41 "k" is coefficient of thermal conductivity. It equals Btu/inch thickness/hr/sq ft deg F. SOUND ABSORPTION COEFFICIENTS AT VARIOUS FREQUENCIES Product Type B-305 B-310 Density Lbe/cu ft .5 1.0 Thickness Inches 1 .14 -12 m 500 1000 000 4000 .25 .51 .80 .78 .76 .30 .68 .94 .82 .80 NRC--Noise Reduction Coefficient--average of coefficients at 250, 500,1000 and 2000 C.P.S. NRC is given to the nearest 5 per cent. (No. 4 Type mounting) . 1582 Insulation. Duct Gustin-Bacon Manufacturing Company 210 W. 10th St. Kansas City, Mo. Distributors in All Principal Cities (Consult Classified Phone Directory) ULTRALITE glass fiber Duct Insulation and Duct Liner Characteristics of Ultralite. Ultralite Duct Insulation and Ultralite Duct Liner are composed of long, fine, textiletype glass fibers, bonded with a thermo setting resin. Both are manufactured and shipped in blanket-like rolls. Both are immune to fire, rot, corrosion, age, rodents and insects, odors, vibration, and are low in moisture absorption. Ultralite is resilient--quickly returns to original dimensions after pressure or bumps during or after installation. 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 and washers, even staples. Ultralite is not unpleasant to handle. Extreme simplicity of application keeps applied costs down. Ultralite Duct Insulation (Thermal). A highly efficient "wrap-on" type ther mal insulation weighing only 1 oz per board foot. 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. (See Sweet's File (Arch.) or write for AIA File 37-D-2) Ultralite Duct Liner (Acoustical). A sound-absorbing insulation to be applied to interior of duct. Effectively absorbs objectional fan, air-rush and trans mitted noises. Also an excellent ther mal insulation that can be used on the exterior of duct. Weighs only 2 oz per sq ft in the % in. thickness. Won't break, chip or dent. Available in }$ in. and 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. (See Sweet's File Architectural or write for AIIA File 37-D-2) G-B ULTRAFINE PIPE INSULATION. A new one-piece molded pipe insulation of fine glass fibers for heated and chilled piping. "K" factor is truly excep tional--.31 at 300 deg. mean. The new 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 . . . can be painted or finished as desired. Snaps quickly on pipe. Single seam can be closed with any standard fastening means. Available in 6-ft long sections, sizes in-10 in. See Sweet's Architectural File or write for Bulletin UFP. 1583 Insul-Mastic Corporation OF AMERICA 1162 Oliver Building Pittsburgh 22, Pa. Representatives In Principal Cities Insulation Adhesive Ducts-Pipe VAPORSEALING'INSULATION fSATION PREVENTION -CORROSION PREVENTION INSUL-MASTIC--A highly viscous, semi-plastic material for the performance of the above functions. It is spray ap plied; adheres to surface at alt angles; and, when dry, remains flexible but ex tremely tough. COMPOSITION--Insul-Mastic was de veloped with the idea of topmost quality. Therefore, Gilsonite, or "mineral rubber" was used as the basic material. This thoroughly saturated hydrocarbon is al most chemically inert and extremely hard to displace by chemical reaction with acids, alkalis or weathering. To this is added a proper balance of high grade asphalt. This combination assures maxi mum service at extreme temperatures. For long life and ease of application, three important fillers are used in InsulMastic; Mica Flake, Asbestos Fibre and Ceramic Clay. See National Bureau of Standards report showing proof of ex cellent results with mica flake used to increase the life of coatings. QUALITIES--Extremely resistant to most acids and alkalis. Not affected by temperatures between --40 F and 300 F. Flexible, stands normal expansion, con traction and bending of surface beneath it. Adheres to any dry, dust free surface at any angle including ceilings. Imper vious to moisture; the moisture vapor penetration rate per in. thickness, per INSULATION--Insul-Mastic Type "D" --To the high quality material described in the opposite column, Insul-Mastic adds 65 to 75 per cent granulated cork. This forms the sprayable insulation known as Insul-Mastic Type "D." This insulation is capable of stopping 65 per cent of heat flow through metal plates. The K factor is 0.36 per sq ft per inch thickness. No mechanical means of at tachment are needed. Insul-Mastic Type "D" insulation may be used indoors or outdoors without covering. It also pre vents corrosion and deadens sound. CONDENSATION CONTROL--InsulMastic Type "D." Insul-Mastic Type "D" also controls condensation when applied to pipes carrying cold liquids or to ducts and panels subject to chilling. Here again it adheres at any angle with out mechanical support. Pullman cars, freight cars, skyscrapers and others em ploy Type "D" for this purpose. VAPORSEALING INSULATION--In sul-Mastic Reinforced With Glasfab Membrane--For keeping soft or semi rigid insulation dry and protected. The system gives the insulation a tough, water repellent covering that is not likely to be broken in spite of the soft material beneath it. Insul-Mastic and Glasfab take the place of asbestos cement and 100 sq in., per 24 hr is 0.01 grams. chicken wire which is brittle, requires APPLICATION--Insul-Mastic is spray two coats plus asphalt; and to the insula applied under heavy air pressure. Insul- tion adds water which may never be Mastic licensees in principal cities have driven off. Insul-Mastic and Glasfab is trained crews to do this work. Coatings a flexible jacketing which can withstand are applied at the rate of six to eight gal abuse such as ladders, foot traffic or fall per 100 sq ft for corrosion prevention and vapor-sealing and at the rate of 20-30 gal per 100 sq ft for insulation and condensa tion prevention. Used as it comes from the drums, no heating required. APPEARANCE--Insul-Mastic is black, ing objects. The Glasfab Membrane is imbedded into a tack coat of Insul- Mastic and then sprayed with a f-in. coating of the mastic. CORROSION PREVENTION--Installa tions of all types from small pipes to large but may be colored with Insul-Mastic tanks can be kept from corroding by a aluminum spray or colored vinyls. Slate coating of Insul-Mastic. In chemically granules of various colors may be blown laden air or constantly moist conditions, . into the coating while it is wet. . this protection is particularly necessary; LIFE--Accelerated weather tests identi and Insul-Mastic's record in paper pulp cal to that of the Bureau of Standards mills, oil refineries and other industries place Insul-Mastic's life at over 50 years in outside weather. where corrosion was a great problem confirms the durability-of this coating. Insulation Duct Owens-Corning Fiberglas Corporation General Offices--Toledo 1, Ohio. Pacific Coast Division. P.O. Box 89, Santa Clara. Cal. Fiberglas A COMPLETE LINE OF INDUSTRIAL INSULATIONS Kaylo Pipe and Block Insulation The low coefficient of conductivity, or "k," of Kaylo Heat Insulation, together with its long life at temperatures up to 1200F makes it ideal for high temperature insulation. Avail able in all standard sizes. Easily cut or fitted on the job. Made of hydrous calcium silicate by Owens-Illinois Glass Co. and distributed by Owens-Coming Fiberglas Corp. Fiberglas* Pipe and Block Insulation Fiberglas PF (pre-formed) Pipe Insulation available in all standard sizes for both low temperature and heated piping. Dual-Temperature Pipe Insulation for use on cold piping or dual-temperature piping. Aerowrap* Pipe Insulation for heated piping, cooled piping, steam traced lines, valves and fittings. Blanket-Type Pipe Insulation for hot pipes up to 1000F, welded pipe and large pipe sizes. Fiberglas PF Insulation, a general-purpose insulation for heated or cooled equipment. Fiberglas TW-F insulating Wool, another general-purpose insulation used for high-temperature equipment and industrial ovens. Metal Mesh Blankets for breechings, tanks, ovens, and other high-temperature equipment. Fiberglas Block Insulation, particularly adapted to breechings, condensers, evaporator kilns and other high-temperature equipment. Fiberglas Dui t Insulations Fiberglas Duct Insulations come in both rigid and flexible forms in six basic types. All deliver top insulating performance against heat and cold plus the additional advantage of sound control. All types are light, fire safe, durable, rot and moisture proof with high insulating value. Fiberglas Vapor-Seal Duct Insulation is ideal for use on air conditioning ducts in warm and humid areas. Built-in vapor barrier of asphalt and kraft paper. Full range of thicknesses for specific tempera tures. Fiberglas Flexible Duct Liner is used as a sound absorber and thermal insulation inside ducts. Available in two thick nesses with high NRC. Fiberglas Flexible Duct Insulation can be used to provide thermal insulation on exterior of ducts of amr shape. Fiberglas Coated Duct Insulation is a versatile product used for both inside and outside duct insulation. Semi rigid with coated surface that permits use as a duct liner. Fiberglas PF Duct Insulation for cover ing rectangular ducts at minimum cost for efficient performance. For detailed information on Fiberglas Insulations lo k in the yellow pages for your local Fiberglas Distributor-Contractor or write Dept. 44, Owens-Coming ] iberglas Corporation, Toledo 1, Ohio. FIBERGLAS (Reg. US. Pat. OS.) and AEROWRAP are trade-marks of Owens-Corning Fiberglas Corporation. , 1585 Insulation AAdirheDsuives: Buildings SpAaya-tflcJze Insulation Co. INdependence 3-8800 2727 Irving Park Road, Chicago 18, 111. "Sprayo-Flake" is a multiple purpose insulation providing a superior combina tion of thermal insulation--sound deadener--condensation elimination--sealer ' against air leakage and infiltration. VERSATILITY: Sprayo-Flake Insula tion is a versatile product of fibrous insulation materials and adhesives suited to Sprayo-Flake Insulation Gun applica tion to structural surfaces having regular or irregular centers, spacing or contours. SPRAYO-FLAKE PROCESS: This proc ess is unique in that it is fabricated and applied in one single, efficient, economi cal operation on the job. The process consists of forcibly projecting, through a special Sprayo-Flake Insulation Gun, dry fibrous materials simultaneously with an atomized adhesive. The ad hesive primes the treated surface and coats the fibers as they emerge from the Sprayo-Flake Insulation Gun, causing them to form a homogeneous, light weight, bonded-on, continuous, cellular insulation coating on the structural sur face treated. Sprayo-Flake Insulation ideal for air condition ing and heating ducts. "Air-Gun-Applied" Insulation Coatings for Steel, Brick, Aluminum, Cement and Cinder Block, Cement and Asbestos Board, Gypsum, Precast Cement Tile, Wood Sheathing and Roof Decks, Con crete Slabs and Walls, etc., in thickness Sprayo-Flake applied on the inner surface of auditorium building walls and roof. of in-> 1 in-, 1 K in-, etc. THERMAL INSULATION APPLICATION On Steel Construction Sprayo-Flake In sulation is especially effective on all types of metal buildings, ducts, etc. Plastic in nature, it bonds and conforms to the surfaces treated without cutting and fitting. Thus it provides substantial savings in both installation and maintenance. Seals joints, cracks and crevices. Eliminates condensation. SPRAYO-FLAKE INSULATION IS BONDED-ON directly to walls, sheathing, ceilings, roof decks, metal ducts, etc. The Sprayo-Flake Insulation Mat covers all cracks and crevices. It provides a highly efficient insulation and also seals the exposed surfaces against cold and warm air infiltration. ON ALL TYPES OF CONSTRUCTION Sprayo-Flake Insulation is ideal because it is bonded securely to.the surfaces treated providing highly efficient life-time insula tion. The emulsified asphaltic adhesive used in applying Sprayo-Flake Insulation is one of the finest damp-proofing agents known to the construction science. Sprayo-Flake "K" Factor 0.246 Btu for I in. Thickness SPRAYO-FLAKE "SPRAYED-ON" INSULATION is ideal for Housing Projects, Homes, Public Institutions, Industrial Plants, Defense Projects, Storage Tanks, Dust Collectors, Laboratories, Broadcasting Studios, Office Buildings, Commercial Buildings, Apartment Buildings, Cold Storage Plants, Warehouses, Banks, Public Utility Buildings, etc. SOUND INSULATION: Sprayo-Flake Insulation is a very effective sound deadening insulation on floors, walls, ducts, etc. Sprayo-Flake data booklet on request. 1586 Insulation Cork Armstrong Cork Company Building Materials Division Lancaster Pennsylvania Offices Albany Allentown Anchorage Atlanta Baltimore Billings Birmingham Boston Buffalo Charlotte Chicago Cincinnati Cleveland Columbus Dallas Denver Detroit Fairbanks Harrisburg Hartford Henderson, Ky. Houston . Indianapolis Jacksonville Kansas City Los Angeles Memphis Milwaukee Distributors Minneapolis Nashville New Orleans New York Omaha Philadelphia Pittsburgh Portland Pbovjdencb Richmond Rochester St. Louis San Francisco Seattle Spokane Tacoma Tulsa Washington, D. C. Wilmington Charleston 23, W. Va.. .C&pit&l City Supply Co. Eao Claire, Wib.............................. Horel-George Co. Fort Watnr 5, Ind............................ The Baldus Co. Grand Rapids, Mich. Tony Batenburg Insulation Co. Joplin, Mo........................................Joplin Cement Co. Manitowoc, Wib. Northwestern Asbestos and Cork insulation Co. Phoenix, Abiz. ...;.......................... Barrett & Holmes. San Antonio, Tex........ General Supply Co Inc South Bend 23, Ind........ Midland Engineering Co. Springfield, Mo...........Southwestern insulation Co Armstrong's Contract Service Armstrong's Contract Service provides trained engineers, supervisors, and in stallation crews that are thoroughly ex perienced in the application of both highand low-temperature insulations to ducts, piping, and equipment. Backed by more than 40 years of service in the insulation held, this nation-wide organi zation will see that your job is done right from start to finish. Your nearest Armstrong office will furnish prompt estimates and technical assistance with out obligation. The following products are available for installation by Armstrong's Contract Service or for your own application: Armstrong's Corkboard Armstrong's Corkboard is the standard low-temperature insulation. Properly ap plied to ducts and other air-conditioning apparatus, it will greatly improve the over-all thermal efficiency and the op erating characteristics of the system. It will also prevent moisture condensation and copsequent drip.from air-condition ing ducts and equipment surfaces. The exceptional moisture resistance and durability of Armstrong's Corkboard assure lasting insulating efficiency. Strong and light in weight, this material is easy to handle on the job. It is readily cut and worked with ordinary tools and may be shaped to fit curved surfaces. It provides a firm bond with all conven tional finishes. Conforms to Federal Specification HH-C-561b. Sizes: 36 in. long; 12 in., 18 in., 24 in., and 36 in. wide; 1 in., 1} in., 2 in., 3 in., 4 in., and 6 in thick. K factor: 0.26 at 60 F mean temp. Armstrong's Cork Covering Armstrong's Cork Covering has the same high insulating efficiency and gen eral characteristics as Armstrong's Cork board. The use of Armstrong's Cork Covering on cold lines prevents from 80 to more than 90 per cent of the refrigera tion loss occurring when lines are left uninsulated. Pipe and fitting covers are machined to accurate size and finished irith a heavy mastic coating which pro vides a seal against air and moisture penetration. Pipe covering is made in 36 in. half-sections to fit all standard pipes and tubes from in. o.d. up. Fit ting covers are made for all sizes of valves, elbows, tees, and other fittings. Covers for special sizes and shapes made to specification on request. Three thick nesses: Light Duty Thickness (1.2 in. to 1.93 in.) for temperatures from 35 F up; Standard Thickness (1.7 in. to 3.5 in.) for temperatures from 0 F to 35 F; Heavy Duty Thickness (2.63 in. to 4.19 in.) for temperatures from --25 F to 0 F. Heat Insulations In most areas, Armstrong is the sole distributor of Keasbey & Mattison's complete line of heat insulations. These materials are available for direct sale .or as installed by Armstrong's Contract Service. They include 85 per cent mag nesia block and pipe covering, air cell block, sheet, ana pipe covering, hightemperature block and pipe covering, wool felt, hair felt, etc. All are available in standard sizes and thicknesses. For detailed technical information, samples, and descriptive literature, ask any office or distributor Specifications appear in Sweet's Catalogs for Architects and Engineers 1587 Insulation The Celotex Corporation General Offices 120 South LaSalle Street, Chicago 3, 111. CeloieX REG. U. S. PAT. OFf. Celotex Insulation Board Products are made by felting long, tough cane fibers into strong, rigid boards. Manufac tured under the patented Ferox* Process. Ferox-treated Celotex board has been demonstrated by laboratory tests and years of use to be protected effectively against dry rot and termite attack. In tegrally waterproofed. Celotex Insulating Sheathing--For use in frame construction under wood siding, wood or asbestos shingles, stucco, or masonry veneer. Double-Waterproofed-- integrally treated, then asphalt-coated on all surfaces. Exceeds government vapor permeability requirements. Sizes: 4 ft wide x 8, 9, 10, 12 ft long x *56 in. or in. with square edges. 2 ft x 8 ft x '$6 in. with V-type tongue and groove on long edges. Celotex 4 ft unde 25/S2 iii. Shealhing, applied vertically without comer bracing, greatly exceeds racking strength require ments set forth in FHA Technical Circular No. 12 (racking strength at least equal to horizontally-applied wood sheathing with let-in bracing is minimum requirement). thickness. Same moisture-resistant as phalt coating as Preseal. Size: 24 in. x 48 in. Thicknesses: 1 in., li in., 2 in. Channel-Seal--Specially fabricated with lHs in. x H6 in. bevel on underside of all edges to form interconnecting channels for equalizing air pressure between roof ing and deck. Asphalt-coated all surfaces and edges. Size 24 in. x 48 in., thicknesses 1 in., 1)4 in., and 2 in. Conductance, "C," of 0.33 Btu for nominal one inch thickness after coating. Flexcell* Expansion. Joint Filler--Cane fiber felted into strong, resilient boards, then saturated with durable asphaltic compound. For expansion joint uses, perimeter insulation for concrete floors at gTade, sill Bealer, plate sealer, and vibration isolation. Thicknesses of I in. to 1 in. in various lengths and widths. Cemesto* Structural Insulating Panels-- Completely fabricated panels for curtain walls, roof decks and partitions. Con sists of cane fibre board core surfaced on both sides with layer of asbestos-cement board. Sizes: 4 ft wide x 6 ft to 12 ft lengths- Special sizes available. Thick nesses: 11/16 in., H in., 1& in., 2 in. Celotex Insulating Lath--Insulation and continuous plaster base in one material. All edges beveled for additional plaster Celotex Rock Wool Products--Regular Blankets, full- or Bemi-thick, 15 in. x 96 in., 15 in. x 48 in., 15 in. x 24 in. Utility reinforcement at joints. Long edges Blanket, 15 in. x 96 in. Reflective Blan shiplapped- Sizes: Regular or Vapor- kets, standard thickness, 15 in. x 96 in. Seal, 18 in. x 48 in. x J in. Also Loose, Granulated and Hand-Pour Celotex Roof Insulation Regular--Natural cane fiber board sur face. Provides excellent bond for pitch or asphalt. Meets requirements for Roof Insulation Board (Class C) of Federal Specifications LLL-F-321b, Commercial Standard CS42-49 of U, S. Department of Commerce, and ASTM Specification C208-48. Sizes: 23 in. x 47 in,, 24 in. x 48 in. Thicknesses: $ in., 1 in., 1J in., 2 in. ing Rock Wool. ' Q-T* DuctUner--Sound absorbing ma terial designed for duct lining in air conditioning systems. Made of rock wool and special binder. Withstands air duct humidity, is fire-resistant and will not support combustion. Thermal conductivity of 0.30. Celotex Sound-Conditioning Products-- Complete line of specialized acoustical materials to comply with every require ment, specification, or building code. Preseal--Coated with special asphalt on Distributors in principal cities. all surfaces and edges for additional moisture protection. Size: 24 in. x 48 in. Thicknesses: i in., 1 in., ljr in., 2 in. Preseal "SO"--Extra high quality board with conductance "C" after asphalt coating of 0.30 Btu per inch nominal Celotex Interior Finishes--Tile Board, Finish Plank, Building board--triple duty products that build, decorate, in sulate. Variety of sizes and finishes. "Reg. U. S. Pat. OS For detailed information on all Celotex products, see Sweet's Files of write The Celotex Corporation 1588 The Dow Chemical Company Plastics Sales, Midland, Michigan Insulation STYROFOAM RIGID LOW TEMPERATURE BOARD INSULATION PROVIDES EXCEPTIONAL RESISTANCE TO WATER, ASSURES LONG SERVICE LIFE You'll find that Styrofoam . . . Dow's rigid low temperature board insulation ... is right for your job. Styrofoam combines all the factors you want: high thermal re< sistance, low original cost, long service life and a minimum of maintenance. Commercial applications in many fields prove Styrofoam is an excellent rigid-type low insulation material. Its cellular structure provides exceptionally high resistance to water and water vapor. Styrofoam's low "K" factor (0.23-0.27 Btu/sq ft/hir/F/ inches at a mean temperature of 40F) assures maximum thermal efficiency. Styrofoam is available in two grades: Styrofoam 22 (regular) and Styrofoam 33 (self-extinguishing). For more detailed information contact your nearest sales office. Atlanta Boston Chicago Cleveland Detroit Houston Los Angeles New York Philadelphia St. Louis San Francisco Seattle. STYROFOAM GIVES YOU ALL THESE ADVANTAGES FOR: Pipe Covering Insulated Vehicles Refrigeration Equipment Low Temperature Rooms * Perimeter Insulation High Thermal Resistance Water Resistance, freedom from capillarity Long Insulation Life Low Cost-Installation, Maintenance, Operation Odorless ' Resistant to Rot and Mold Light Weight * Easy to Fabricate Sizes for any job Thicknesses: 1,1)4, 2, 3, 4, 5 in.--Widths: 10 in. and 12 in.--Lengths: 36 in. and 9 ft. 1589 Insulation INSULITE DIVISION Minnesota General Office: 500 Baker Arcade Bldg. and Ontario Paper Company - -Minneapolis 2, Minnesota mSUUTE STRUCTURAL INSULATION BOARD For 40 years engineers and architects have specified Insuiite materials for struc tural uses, interior finish, and for other thermal insulation and sound control work* Insuiite materials have proved their merit through actual performance on the job, STRUCTURAL MATERIALS - CONDENSATION CONTROL--To pre vent condensation within walls, author ' Lok-Joint Lath proved Insuiite (inside) form the ap "Wail of Protection." ities recommend "sealing the warm side and venting the cold side" of the wall. Transmission coefficient (U) for this construction with wood siding exterior is Sealed Lok-Joint Lath provides the nec essary vapor barrier on the warm side of the wall, thereby reducing the flow of vapor into inner wall areas. On the cold 0.15 Btu/hr/sq ft/F. This value is typical of the results gained by using Insuiite materials in frame construction. For further (U) vab side of the wall, vapor-permeable Bild- ues see Chapter 9, pages 182 and 187. rite Sheathing allows surplus vapor to escape towara the outside. SHINGLE-BACKER Bildrite* Sheathing--A tough, durable, insulating sheathing material made from new wood fibers. Waterproofed through out by an integral asphalt treatment. Shingle-Backer is a fast-applying, in sulating undercourse material for double-coursed shingled walls. Made Bildrite (4 ft. width) has more than from Ke-in. insulation board, water twice the bracing strength of horizontal proofed throughout with asphalt. wood sheathing. thick. Sizes: There are two Shingle-Backer Sys 2 x 8 ft (V-joint on long edges) . . . tems. One is for wood-shingled side 4 x 8 ft to 4 x 12 ft (square edges). Ther mal conductivity: 0.37 Btu per inch thickness. Also available is J^-in. Graylite Sheathing. Sealed Lok-Joint Lath*--An insulat walls. Shingle-Backer's 4-ft long panel? take the place of low-grade wood under course sningies. Makes faster, easier, better-looking shingled walls at low cost. Two widths: 13} in. for 12-in. ing plaster base, made from tough North shingle exposure. 15J in. for 14-in. ern wood fibers. Horizontal joints are shingle exposure. Four ft long. reinforced by metal "Loks." Water A different Shingle-Backer System proofed throughout by an integral as is used for asbestos-cement siding phalt treatment. Asphalt vapor-barrier shingles. 11^-in. Shingle-Backer is protects against harmful condensation. used to give modern shadow-lines. Thicknesses: and 1 in. Size: Also protects against breakage, helps 18 x 48 in. Also available without vapor seal in J^-in. thickness. THE INSULITE "WALL OF PROTECTION" sound condition nouse. Both systems give added insulation, greater structural strength and weather resistance. No building paper is re quired. Can be applied over Bildrite Bildrite Sheathing (outside) and Sealed and Graylite* Sheathing. Applying Bildrite Sheathing 1 1590 Applying shingles and Shingle-Backer Insuiite Insulation ROOF INSULATION INTERIOR FINISHES ' Insuiite Roof Insulation is fabricated from either Ins-Lite or Graylite insula tion board. The in. thickness has square edges. The 1,1 and 2-in. thick nesses .are multiple layers stapled or cemented together. Available with either square or offset edges. Size: 24 in. x 48 in. Graylite Building Board--A rugged, durable board, integrally treated with asphalt for maximum strength and moisture resistance. Thermal conduc tivity is 0.37 Btu per in. thickness. Sizes: 4 x 6 ft to 4 x 12 ft. Thicknesses: Ht and 1 in. Primed Graylite Building Board-- INSULATING WOOL Insuiite Insulating Wool is made from Identical to regular Graylite Building Board, but has a prime coating for easy painting. Sizes: 4 x 6 ft to 4 x 12 ft. famous "Fiberglast," consisting of Thicknesses: }4 and % in. ` millions of long glass fibers bonded to gether with a thermo-setting resin. Available in the following forms: roll blankets, batt blankets, utility batts, plain, batts and pouring wool. Perimeter Insulation--Fiberglas Per imeter Insulation, guards against heat loss in basementless houses. Meets F.H.A. and specific job requirements. Type AE-6 (asphalt enclosed), Type PF-615 (paper faced) and Type PF-6I9 (paper faced, load bearing). Smoothlite* Interior Board--A naturalcolored, factory-coated board with glossy finish. 68 per cent light reflec tion. Sizes: 4 x 6 ft to 4 x 12 ft. Thick nesses: % and in. Wevelite* Interior Board--A practical, low-cost interior board with flameresistant finish in a white color. Sizes: 4 x6 ft to 4 x 12 ft. Thickness: in. Durolite* Interior Board--Butt joint, either or %-in. thickness with square edges and flame-resistant finish. Avail INDUSTRIAL INSULATION Choose from Six Types (1) Low Density lns-Lite*--a low density board .with high insulating effi ciency and maximum sound absorption. Density 10.0 to 12.5 lbs/cu ft. (2) Medium Density Ins-Lite--an " insulating board which provides efficient insulation and structural strength. Density 12.5 to 15.0 lb/cu ft. (3) High Density Ins-Lite--designed to be used where insulation and struc tural strength are required. Density 15.0 to 17.5 lbs/cu ft. (4) Low Density Graylite--a. highly efficient insulating board integrally treated with asphalt for increased strength and resistance to water absorp tion. Density 13.5 to 16 lbs/cu ft. (5) Medium Density Graylite--an in sulating material integrally treated with asphalt. Has high strength and resistance to water absorption. Den sity 16.0 to 18.5 lbs/cu ft. . (6) High Density Graylite--an insu lating material with maximum strength and. resistance to water absorption. Density 18.5 to 21 lbs/cu ft. able in a four ft width and 6. 7, 8, 9, 10 and 12 ft lengths. Colors: wnite, ivory, pearl gray, pale green and light woodtone. Lusterlite Tileboard--A smooth, flameresistant finished board, in white, mist green, and light ivory colors. Has flanged tongue-and-groove joint for easy, secure fastening with staples, nails or adhesive. Thickness: in. Sizes: 12 x 12 in. to 16 x 32 in. Durolite Plank--Flanged tongue-andgroove joints permit easy, concealed fastening with staples, nails or adhesive. Textured, flame-resistant surface finish. Available in and %-in. thicknesses. Colors: ivory, pale green, pearl gray and variegated woodtones. Sizes: 34 in. Plank is 8, 12 and 16 in. wide; and 8 and 12 ft long. in. Plank is 16 in. wide and 8 ft long. Fiberlite Acoustical Tileboard--A low-cost, highly efficient acoustical tile, factory-applied white finish. Beveled edges on all sides. Sizes: 12 x 12 in. to 16 x 32 in. Thicknesses: and in. Acoustilite* Perforated Tileboard--A rugged, sound-absorbing tileboard for residential and commercial interiors. HARDBOARD PRODUCTS Insuiite HardBoard is a rigid, durable, wood-fiber material with tremendous strength. Available in a range of densities from 55 to 68 lb per cu ft. Thicknesses from Jfo to in. Sizes from 3 x 4 ft to 4 x 12 ft. Standard tile units contain 484 cleanlydrilled holes. Available with either flanged tongue-and-groove joint (for staple or nail application) in }^-in. thick ness, or beveled butt-edge joint (for adhesive or nail application) in or in. thickness. Also random drilled Acous tilite Tileboard in or %-in. thickness. Reg. U. P. Pat. Off. 1 Reg. U. S. Pat- Off.--Made by Owens-Coming Fiberglas Corp Factory-applied white finish has high light-reflection. Two types of flame-re sistant finishes. Size: 12 x 12 in. 1591 Insulation Johns-Manville Executive offices: 22 East 40th Street, New York 16, N. Y. Offices in AU Large Cities Home Insulation For New Construction;' Spintex Insulation v Batts and Blankets . Johns-Manville Batts and Blankets are made of spun rock wool. Instead of the short, coarse fibres inherent in other types of mineral wool, J-M produces long, fine fibres. These fibres are felted into batts and blankets that are stronger, lighter in weight, more resilient and with greater uniformity throughout. FtJL-THIK BATTS are fabricated of spun rock wool which assures maximum comfort and fuel savings. Each batt has a vapor-seal backing paper with ex tended tacking flanges for over-lapping at the framing members which protects against passage of abnormal humidity. Applying Spintex balls in new home Furnished in sizes 15 x 24, 15 x 48, 19 x 24, 19 x 48, 23 x 24 and 23 x 48 inches. For Existing Homes and Buildings; J-M Spintex "Blown" Home Insulation J-M Spintex Home Insulation is blown pneumatically into the spaces between studs in outer walls and between roof rafters or attic floor joists. Insulation thickness in walls corresponds to stud depth, approximately 3% in. The uni form fill assures maximum thermal effi ciency. This type of insulation is installed only by Approved J-M Fran Also furnished Semi-Thik in the same sizes. ' THICK BLANKETS are quality home insulation blankets fully enclosed in a permeable Kraft paper wrapping. Iri this blanket the spun rock wool is firmly felted as in the FuLThik Batt, then en cased for convenience in handling. 'It is also backed with a heavy vapor barrier with reinforced tacking flanges. Fur nished in sizes 15 x 48 and 23 x 48 in* chised Home Insulation Contractors, MEDIUM BLANKETS are used where whose trained crews are equipped with insulating requirements are not as exact the necessary apparatus. ing and where first-cost economy is a fac tor. Furnished in sizes 15 x 64 ft, 23 x 64 For complete information on J-M ft, 15 x 96 and 23 x 96 in. , Spintex "Blown" Home Insulation and its application, write the address above or call your local Johns-Manville ! SERVICE BLANKETS are also made of | spun rock wool and are furnished in office. sizes 15 x 96 and 23 x 96 in. Airacoustic* Sheets for lining Air-Conditioning Ducts Airacoustic Sheets, for duct linings of air conditioning systems, are flame proof, highly sound-absorbent and moisture-resistant, with a surface which will not materially increase friction losses in the duct system. Airacoustic Sheets are furnished 24 x 36 in., Y, 1 and \Y in. thick. Pipe and Boiler Insulations Pre-Shrunk Asbestocel* ure-resistant, asbestos felts. Three fin ishes: Glazed White for quick applica Cellular type of insulation for pipes tion, will not carry flame; asbestos paper; carrying low pressure steam or hot water. and regular canvas cover. Made up of alternate layers of plain Furnished in 3-foot sections, in follow-' and corrugated, specially-treated, moist ing thicknesses: Coarse Corrugated, 2 to 8, i in. plies and Fine Corrugated,6 plies Keg. U. S. Pat. OB per inch of thickness. 1592 Johns-Manville Insulation PIPE AND BOILER INSULATIONS, Cont'd J-M?85% Magnesia Superex* Combination Recommended as the most widely used insulation of the molded type for tem peratures up to 600F. Pipe insulation is furnished in sectional or segmental form for all standard pipe sizesf, in nominal thicknesses up to 3 in.'Flat blocks are 3,6,9,12 in. wide and 18 and 36 in. long. Also furnished in curved blocks. Other sizes and greater lengths available on special order. Superex Combination Insulation (an inner layer of high temperature Superex and an outer layer of 85% Magnesia) is recommended where (emperatures ex ceed 600 F. Both Superex and 85% Mag nesia insulations are furnished in sec tional and segmental pipe covering, as well as in block forms. Asbestocel* Asbestocel Sheets and Blocks are used for insulating low pressure boilers, feed water heaters and warm air ducts. Temperature limit 300 F. Furnished 6 to 36 in. wide by 36 to 96 in. long, from Y in. through 4 m. thick. Rock Cork* J-M 85% Magnesia Pipe Insolation Pre-Shrunk Wool Felt J-M Pre-Shrunk Wool Felt is equally effective and durable on either hot or , cold water service piping. Prevents sweating on cold water pipes. Made of a specially indented wool felt and provided with a dual service liner. Supplied in canvas finish or weather proof jacket in 3-ft sections in thick nesses of Y in., in., 1 in., 1Y in. and 2 in. single layer; 1 in., 1Y in. and 2 in. double layer, for all standard pipe sizes.f Temp, limit 225F. Asbesto-Sponge* Felted Recommended on all high pressure steam piping at temperatures to 700 F where insulation may be subjected to rough usage or where both maximum efficiency and durability are desired. Furnished in 3-ft sections from 1 in. to 2 in. thick, single layer; over 2-j in. thick in double layer, for all standard pipe sizes.t Rock Cork is made of mineral wool and an asphaltic binder molded into sheets and .pipe insulation for all low temperature service to minus 400 F. ft is strong, durable, and will not support vermin. Because of its unusual moisture resistance, its high insulating value is maintained in service. Furnished in sheets 18 in. by 36 in., (18 in. by 18 in. available in 1 in. thick ness only), in 1,1%, 2,3, and 4 in. thick nesses. Lagging, for curved surfaces, supplied 18 in. long by 1Y through 4 in. thick, 2 to 6 in. wide, depending on diam eter. Pipe covering furnished in Ice Water, Brine, and Heavy Brine thick nesses, for all commercial pipe sizes.t Discs also available to a 36 in. max. diameter. Zerolite* Zerolite is a resin bonded, mineral wool insulation for temperatures to minus 400 F. In addition to possessing the same basic characteristics as Rock Cork, Zero lite is highly fire-retardant, resists petro leum and organic solvents, and has the added advantage of lower conductivity. Furnished in sheets 18 in. by 36 in! (18 in. by 18 in. available in 1 in. thick ness only), in 1 in. through 4 in. thick ness. Lagging furnished in same sizes as Rock Cork. Details on Request For further information about J-M Insulations and J-M Application Serv ice, write Johns-Manville. 22 East 40th Street, New York 16, N. Y. Reg. U- S. Pat. OH. t Also available in sections to 6t straight runs of copper pipe or tubing with nominal diameters of 9s in. and larger. 1593 Insulation Kimberly-Clark Corporation Neenah, Wisconsin - 1 Kimberly Clark . New York 17, N. Y., 250 Park Avenue *'Atlanta 3, Georgia, 900 Peachtrbb St., N. E. jChicaqo 3, Illinois, g S. Michigan Avenue ISan Francisco 4, Calif-., 155 Sanbomb Street gReflective and Regular KIMSUL* is unique among building in sulations and acoustical materials be cause it is made of many individual plies --each one a continuous separate layer of soft, clean, creped, asphalt-treated cellulose fibers. Each ply is controlled carefully in manufacture both as to thick ness and crepe structure. The result is a flexible blanket, inherently uniform in thickness--an important factor in a thermal or sound insulating material. The Kimsul plies and cover of the creped Pyrogard* or creped Reflective Vaporseal are held together with rows of strong stitching that prevent sifting and settling. No heat-leaking thin spots, no money-wasting thick spots in the Kimsul blanket. Reduced to its installed volume for easier shipment, handling and storage, the Kiinsul blanket is expanded in installation. The stitching controls expansion to the density of maximum efficiency. KIMSUL INSULATION IS NOW MADE IN TWO GRADES--REFLECTIVE AND REGULAR--SEE PAGE OPPOSITE I. 3No. 1. Flexible--fits into corners, tucks behind pipes, electrical wiring and other "tight spots." No areas unprotected. No. 2. Clean--no sharp particles to irritate, nothing to sift; stitched ply construction prevents settling or sagging. No. 3. Caulkable--one ply or many plies may be compressed to high density in narrow or wide joints, sealing out cold air and sound. Kimsul asphalt-treated wood fiber does not break up during caulking or tamping. 4. o. No. 4. Insulated Fastening Edge--The many layer Kimsul blanket is extra wide to provide fully insulated fastening edges, and to ensure completely filling spaces where framing may be slightly off center. No. 5. Over-Framing Compressibility--Kimsul is easily compressed over framing members. Especially valuable for 48 in. wide Kimsul--suitable for mass or prefab rNicoa. te6d. AcnoynsWtruidctthio,nA. ny Length--it's easy to cut exact lengths or narrow widths. Avoids muss and fuss. Workmen do a fast, neat job--with Kimsul. T. M. Rar. U. S. Pat. Off. 1594 Kimberly-Clark Corporation Insulation Now Available--Reflective KIMSUL* Insulation The text of these two pages applies to both Regular and Reflective Kimsul Insulation. The differences in the two types are: Reflective Kimsul has a cover of aluminum foil that acts both as a vapor barrier to shut out condensation, and as a highly efficient reflective surface to turn back radiant heat. Reflective Kimsul has strong reflective tacking flanges for easy, secure attachment to framing. For heat flow downward, ' Reflective Kimsul provides additional insulating value. Regular Kimsul has the Pyrogard fire-resistant cover. Fire-Resistant--Special permanent chemical treatment makes Kimsul resist fire. Pyrogard* Fire-Resistant Cover--(safety feature of Regular Kimsul) resists flamespread. Creped Aluminum Foil Cover--(a feature of Reflective Kimsul) reflects heat, shuts out condensation. Moisture-Resistant--asphalt treatment of each ply sheds water. . Resists Mold, Rot, Vermin--The materials of which Kimsul are made offer no subsis tence to vermin or insects. Special chem ical treatment resists mold and fungus. "fc" Factor--0.27 Btu/sq ft/hr/F. Reflective KIMSUL installed. Edge offastening flange folded aver face of framing completes the vapor seal. Air Space--is a prime requisite. Use a vapor-permeable building paper under ex terior finish. Ventilation in attics and floors should never be omitted. .Use approxi mately one sq ft of louver area for 1000 sq ft of ceiling area. SOUND CONTROL Sound Deadening (one room to another). Kimsul flexible blanket used in staggered stud construction. - ------ . - Lath and Platter 1) Absorbs sound from diaphragmatic action of wall panels. 2) Absorbs sound which leaks through joints, thus main taining original sound resistance of partition. 3) Cushions wall surface. . 4) Prevents accidental bridging. -Sound Absorption (within a room). The blanket design makes Kimsul inexpen //yyy/yy//yyys/y/yy/y///s,,, `-- -KIMSULj sive as a sound absorbing element. See coefficients below. T.M. Reg. U. S. P<U. OS. M PERFORATED BOARD, FABRIC L OH wire screen facing CONSTRUCTION DETAILS AND HEAT FLOW (U) FACTORS Kimsul Grade Heat Flow Horizontal UNINSULATED REG. COMMERCIAL THICK w STANDARD THICK u DOUBLE THICK REFLECTIVE MED. THICK " DOUBLE THICK .25 .15 .12 .08 .10 `U 69 40 .25 52 .17 .10 15 .10 % "U" hi ..2408 75 .15 85 78 ..0190 S5 .08 % "U" .28 58 69 ..1126 81 .08 79 .09 83 .07 % 43 7618 75 >up wi jcncvuve uuver.s r acwjra expressed m Btu/sq Jt/hr/'F; k, per inch of t section of construction. Calculation based on KHA Technical Circular No. of uninsulated heat flow stopped in the insulated construction. , dated Jan. 1949. For further Information write to . KIMBERLY-CLARK CORPORATION--NEENAH, WISCONSIN 1595 Lockport Mills, Inc. (Formerly Lockport Cotton Batting Co.) Thermal and Acoustical INSULATION Dept C. Lockport, N. Y. Insulation ij) Moisture-Resistant--Chemical treat ment, combined 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. Flexible--Cotton batt may be ex panded or contracted to fit any enclosure. Easy to Warehouse and Handle. Qffers far more "compressibility." Requires one-third the trucking and warehouse space of ordinary insulation. Five featured types to meet every insu lation need: (1) OPEN BLANKET backed . by tough, waterproof, asphalt-coated' kraft paper to form an effective vapor barrier. (2) ENCLOSED BLANKET. Insulation completely enclosed in enve lope, asphalt-coated paper on one side, porous or "breather" type paper on other. (3) OPEN ALUMINUM FOIL. All the features of Open Type I plus the extra value of aluminum foil backing. Effective vapor barrier . . . stops 90 per cent of radiant heat. (4) ENCLOSED ALUMINUM FOIL. Superior in insula tion plus values and thermal efficiency. (5) DOUBLE FOIL, aluminum foil on top and back, plus superior Lo-K Blanket efficiency for tops in insulating value. Thermal Conductivity--The "k" value tor cotton is 0.24 Btu/hr/sq ft/degree F/inch. (See table.) Light Weight--Weight of 1 cu ft is 34 lb. (See table.) Flame-Proofed--Withstands 1800 blow torch heat. Simple and Economical to Install. Saves from 25 to 40 per cent in costs. Designed to Maintain Maximum Utility. Resists all types of deterioration. Won't sag or settle. Packaged in Rolled Form. Thicknesses--inches: I, 1)4, 2, 3, 334Width--16, 20, 24 in. centers. Lengths: Standard from 12 ft up. INSULATING VALUE OF VARIOUS INSULATORS* The coefficients of conductivity (k 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 rock............................................ Mineral Wool: Fibrous material made from mineral slag................ Glass Wool: Fibrous material made from glass slag................................... Rigid Insulation made from sugar cane fibre............................................ Chemically treated wood fibre be- tween layers of paper..................... Eel grass between layers of paper .. Stitched and creped expanding fibrous blanket................... ;............ Shavings: Various from planer-- Corkboard: No binder added......... Rigid insulation made from wood Rigid fibre board made from shred ded wool and cement......... ........... .875 10.00 1.50 13.50 3.62 3.40 1.50 8.80 7.00 15.90 24.20 0.24 0.27 0.27 0.27 0.33 0.25 0.25 0.27 0.41 0.27 0.33 0.46 "Compiled from Chapter 0, b"fc" indicates temperature conductivity. Insulation Mundet Cork Corporation 7105 Tonnelle Ave. insulation division North Bergen, N. J. Manufacturers of Corkboard, Cork Pipe Covering, Compressed Machinery Isolation Cork, Natural Cork Isolation Mats, and all kinds and varieties of Cork Specialties, also 85 per cent Magnesia Insulation in pipe covering A block form. Complete Insulation Services for High and Low Temperature. Atlanta, Ga. Baltimore 30, Mo. Boston (W. Cambridge) 38 Cincinnati 2, Ohio Cleveland, Ohio Mundet Branches Dallas 10, Tex. Kansas City 1, Mo. Detroit 21, Mich. Houston 11, Tex. Knoxville 16, Tenn. Lob Angeles (Maywood) Indianapolis 3, Ind. New Orleans 16, La. Jacksonville 6, Fla. New York 17, N.Y. Philadelphia 39, Pa. St. Louzs g. Mo. San Francisco 7, Calif. Washington, D.C. Mundet Distributors are Located in the Following Cities--Names and Addresses on Request Albany, N. Y. Bakersfield. Calif. Beaumont, Texas Bloomfield, N. J. Buffalo, N. Y. Chicago, III. Denver, Colo. Ebie, Pa. Hartford, Conn. Johnson City, Tenn. Mobile (Pritchard), Ala. New Haven, Conn. Norfolk, Va. Oklahoma City, Okla. Pittsburgh (Mt. Leb anon), Pa. Sacramento, Calif. St. Paul, Minn. Salisbury, Md. Salt Lake City, Utah San Diego, Calif. Savannah, Ga. Seattle, Wash. Stockton, Calif. Tucson, Abiz. Tulsa, Okla. Watsonville, Calif. Wilmington, Del. Youngstown, Ohio Natural Cork--Cork in its natural state consists of minute hermetically sealed cells containing "dead" air. Approxi mately 200,000,000 cells per cubic.inch. Cell walls are resinous, resilient, and im pervious to the passage of air. There is no "free" air to conduct heat or moisture and no capillary attraction. LOW TEMPERATURE INSULATION Mundet "Jointite" Corkboard Natural cork is ground into 34 in. to % in. granules and compressed under heat in moulds to produce Mundet fiat or shaped corkboard. Air spaces between granules are eliminated by the pressure and the milled resin in the cell walls cements the mass into a homogeneous structure retaining the properties of natural cork. Mundet Corkboard meets U. S; Government Master Specifications. Its heat transmission is guaranteed not to exceed .29 Btu when tested in accordance with Bureau of Standards regulations. In actual cold storage practice, this figure may be safely reduced to .27 Btu. Sold in standard 12 in. x 36 in. sheet. Standard thicknesses, % in., 1 in., 1)4 in., 2 in., 3 in., 4 in., 6 m. Mundet "Jointfte" Cork Pipe Covering Protects all types of low temperature lines. Made in 3 thicknesses, with com plete line of standard covers, suitable for pipes carrying sub-zero to 50 F tem perature. - HEAT INSULATION 85% Custom-Molded Magnesia The new Mundet plant for the manu facture of 85 per cent magnesia insulation makes available the most modem plant facilities for the production of heat insu lation in pipe covering and block forms. Mundet Cork Vibration Isolation Machinery vibration encountered in heating and ventilating work is effec tively controlled by the use of Mundet Natural Cork Isolation Mats. We also manufacture sheet isolation cork for heavier machinery loads. Engineering and Specification Service Our engineering department is at the service of Architects and Engineers, to assist and advise in the preparation of specifications. This service is available without obligation. Mundet Contract Service Covers the complete installation of our iroducts, in accordance with best estab- fSection of Mundet Moulded Cork Pipe Covering with Fitting. The pipe covering is made in sections $6 in. long, to fit all sizes of pipe. ished practice. Divided responsibility is avoided. Materials and workmanship are guaranteed. Send for catalog. 1597 i Insulation The Pacific Lumber Company 100 Bush Street, San Francisco 4, Calif. . 35 East.Wacker Drive, Chicago 1, 111. - ' INSULATION PROVIDES EFFICIENT INSULATION TtAOt IUIK INSULATION THICKNESS--Ceiling insulation should be at least 4 in. thick. We recommend 6 in. thickness, giving 50 per cent more insulation at little added cost. Radiant heating system manufacturers insist on 6 in. thickness for maximum ef ficiency and economy. Insulation in walls should be full stud thickness. Below are typical ceiling sections showing U values for various thicknesses of PALCO WOOL Insulation: - U = 0.047 -- Ceiling joists, sheetrock, full 6 in. thickness PALCO WOOL Insulation over joists. U = 0.0631 -- Ceiling joists, sheetrock, full 4 in. thickness PALCO WOOL Insulation over joists.. U = 0.080-- Ceiling joists,"sheetrock, 3 in. thickness PALCO WOOL Insulation between joists. 9 PROVED QUALITIES High thermal efficiency--K factor of only 0.26 Btu. Non-settling and non-compacting. Flame proof--fire resistant. Moisture resistant. Odorless--won't give off odors. Permanent--will outlast structure. Non-attractive to vermin or insects. Economical--initial low cost, high in sulating efficiency. Resilient--springy structure gives better sound absorption. Typical sound deadening application from Palco Wool Home Insolation Manual WRITE FOR THESE - TECHNICAL AIDS One of many installation details shown in Palco Wool Cold Storage Afanxtal HOME INSULATION MANUAL-- home, commercial sound deadening ap plications. COLD STORAGE MANUAL--construc tion details, all types of cold storage. . LOCKER PLANT MANUAL^--plans, material lists, construction details. FARM PRODUCE STORAGE PLANS for fruit and vegetable storage. FIELD TEST DATA--complete reports on impartial studies of Palco Wool in actual use. 1598 Insulation United States Gypsum Company General Offices: 300 W. Adams Street, Chicago 6, 111. INSULATION PRODUCTS Blanket Type Structural RED TOP* INSULATING WOOL BLANKETS Blankets are enclosed, ends are mill cut. Face of enclosure is a glossy asphalted paper which forms a continuous vapor barrier because width of nailing flanges allows overlapping. Permeability factor, 1.00 Perm. RED TOP blankets have high thermai resistance (see table). They are incombustible; uni formly effective; vermin and deterioration resistant; light in weight; highly resilient. PRODUCT DATA--ENCLOSED BLANKETS Approx. Thick ness Medium 2" Thick 3" Economy I'A" Framing Spacing 16", 20" or 24" O.C. Length 24", 48", 96" 24", 48", 96" 96" Approx. Wt per Sq Ft 0.58 lbs 0.87 lbs 0.48 lbs Conductance (1) (k) (C) 0.27 0.135 0.27 0.090 0.27 0.180 Resistance l/k 3.70 3.70 3.70 1/C 7.40 11.10 5.55 (1) Expressed in Btu per sq ft per hour per degree F temperature difference, (k) is per inch thickness, (C) is for thickness stated. ' USG* INSULATING SHEATHING An insulating, moisture-resistant ex terior wall sheathing. The 2 ft x 8 ft size is in. thick with long edges tongued and grooved. Heat conductance for thickness stated is 0.42 and heat resist ance is 2.37. Other sizes, 4 ft wide by 8 ft, 9 ft, 10 ft or 12 ft long, have square edges and are either in. or % in. thick. USG 2%2 >n. Insulating Sheathing has greater bracing and stiffening strength than conventional narrow sheathing units placed horizontally. USG in. sheathing, 4 ft wide, meets structural requirements established in F.H.A.. Cir cular No. 12, allowing use of sheathing without diagonal bracing. The 2 ft x 8 ft size has long edges tongued and grooved, and ends are joined over supports, thus making wind-tight joints possible with out the use of building paper. USG ROOF INSULATION Internally treated to make it moisture resistant, USG Roof Insulation is supplied in 23 in. x 47 in. size with square edges. Both plain fiber and asphalt treated are available in % in., 1 in., 114 in. and 2 in. thicknesses to meet varied insulation requirements, T.M. Reg. U.S. Pet. Off. 1599 Insulation Wood Conversion Company Dept. 220-4 First National Bank Building New Yobk St. Paul X, Minnesota Chicago ' Buffalo Boston Kansas City Detroit St. Paul San Francisco ' Atlanta EFFICIENT INSULATION FOR EVERY NEED For many years a leader in the insula tion field. Wood Conversion Company manufactures a complete line of flexible fiber and rigid insulation for all indus trial and domestic purposes. This in sulation is the product of scientific research, and is especially designed to embody the most desirable qualities for every use. Backed by the name of Weyerhaeuser, Wood Conversion Com pany insulation assures high efficiency and long, satisfactory service. Balsam-Wool* Sealed Blanket Insulation is a flexible insulation. The insulation. blanket is made from new wood fibers, completely enclosed on both sides and edges with heavy asphalt saturated and coated kraft liners. Years of practical application and con stant testing are behind each of these Balsam-Wool features-- Integral, continuous vapor barrier Sturdy wind barrier Special spacer flange Double bonding of mat to liner Rot and termite treatment Highly fire retardant In addition, Balsam-Wool is manufac tured under rigid quality control ; proved by more than a quarter century of ex perience. Tufflex--A soft, felted blanket material with exceptional insulating and cushion ing qualities. Tufflex is made from clean, new, cellulose fibers, felted and bonded into a fleecy, homogeneous mat, proc essed to resist mold and vermin. It may be moisture resistant or absorb ent. Surfacing of kraft paper can be fur nished on one or both sides; cottonette or scrim can be applied to one side of the plain mat. Where the use requires, Tufflex Type "U" can be furnished with a fire retardant treatment. The soft, but firm, felted construction of Tufflex gives the properties of low trans mittal of heat, sound or vibration, and of holding its shape after being cut. Applying Nn-Wood Interior Finish Applying Balsam-Wool Sealed Insulation NU-WOOD* STRUC X INSULATION Nu-Wood Interior Finish--A multiplepurpose wood fiber material available in tile, plank and board. Nu-Wood insu lates, decorates and quiets noise. NuWood's colors are soft and harmonious-- will not fade. The Nu-Wood interior finish line includes Sta-lite, an insulating interior finish with more than 70 per cent light reflection. Reg. U. S. Pat. 09. Nu-Wood Sheathing--A strong, struc tural insulating sheathing in in. and 25/32 in. thickness, asphalt impregnated, offering complete moisture protection. Nu-Wood Roof Insulation--Will fill all requirements of Federal specification LLL-F-321b. Furnished in any prac tical thickness. M.47.7169 1600 Insulation Reflective American Flange & Manufacturing Co. Inc. 30 Rockefeller Plaza, New York 20, N. Y. . Plaza 7-2200 Terro'fherm Reg. U. S. Pat. Off. STEEL INSULATION FULLY PROTECTED BY U. S. AND FOREIGN PATENTS ISSUED AND PENDING Assures Rapid Pull Down of Temperature The low heat storage capacity of FerroTherm is extremely important in achiev ing rapid pull down of temperature, and in saving refrigeration costs for the initial and each subsequent cooling of space. Specifically, the heat storage capacity of a single sheet of No. 38 gauge is 0.029 Btu per (hr) (sq ft) (*F tempera ture difference). This is approximately 1/16 of the heat storage capacity of 1 sq ft of 1 in. thickness corkboard. Ferro-Therm installed in a cold storage room Ferro-Therm Steel Insulation, made from rigid steel sheets with a special alloy coating, reflects 90 per cent to 95 per cent of all radiant heat. This high reflec tivity, combined with extremely low heat storage capacity, provides maximum insulating efficiency in a minimum over all thickness. Saves Pay Space and Weight In cold storage construction, the number of sheets of Ferro-Therm depends on the temperature to be maintained and the U value required. The k value of FerroTherm, based on tests, is listed in the Data Book of the American Society of Refrigerating Engineers as 0.226 Btu per (hr) (sq ft) (F temperature difference). Laboratory tests and thousands of appli cations have demonstrated that a wall of Ferro-Therm will provide insulating effi ciency equivalent to a wall of mass insulation approximately twice aa thick. Permanent, Fire-Proof Insulation Ferro-Therm construction eliminates trapping of moisture condensate, with subsequent deterioration of the construc tion. As it is all-metal, Ferro-Therm cannot be penetrated by rodents, vermin or termites, and is absolutely non-com bustible. The value of Ferro-Therm for fire protection is apparent. 125 Below Zero Maintained in Altitude Test Chambers Ferro-Therm has proved its superiority in buildings, cold storage rooms, refriger ated cabinets, locker rooms, dry ice con tainers, refrigerated railway car con struction, ovens, high-temperature storage tanks--in fact, practically every type of application where high insulating efficiency with economies in space and weight is a requisite. The most nota ble demonstration of Ferro-Therm per formance has been its selection for the insulation of altitude chambers for the testing of Army and Navy aviation equipment and personnel. In these chambers, temperatures as low as -- 125F were maintained, with a tem perature drop of +70F to -- 70F in 10 to 12 min. 1601 Insulation Infra Insulation, Inc, 525 Broadway, New York, N. Y. Telephone: WOrth 4-2241 THERMAL FACTORS OF INFRA, AND OTHER INSULATION EQUIVALENTS Heat Flow-Type 6 Up-Heat C.089 R.11.23 = 4H" otherinsul. Wall C.073 R.13.69 = other insul. Down C.044 R.22.72 = 9" other insul. Heat Flow-Type 4 Jr., in ONE-INCH Space Up C.194 R 5.15 = 2W other insul. Wall C.150 R 6.66 = 2%' other insul. Down C.097 R 10.30 = A'A" other insul. Infra Insulation, Type 6, is a tough, 3-aluminum-sheet insulation, with 6 heat-rayreflective surfaces, plus two other reflective spaces, and four rows of inner, alternat ing, reverse triangular air spaces. (Total, 6 reflective spaces.) It is easily and quickly installed between wood joists, furring strips, and between steel trusses, metal beams and girders, giving the entire area in between, including the edges, full depth pro tection against heat and vapor flow and condensation formation. The normal installa tion rate between wood joists is 2,000 sq ft a day per man. The 1% cu ft carton con tains 600 sq ft, weighs 46 lbs. Standard width, for 12 in., 16 in., and 24 in. centers. Standard Type 4, for 12 in., 16 in., 20 in., 24 in. centers. Heat flow through wall Bpace, which is air, is about 7 per cent by Conduction; 15 per cent to 28 per cent by Convection; and by Radiation, 63 per cent to 80 per cent. ABSORPTIVITY and RADIATIONEach of Infra's 6 accordion aluminum surfaces has an absorptivity of 3 per cent and a reflectivity of 97 per cent for radiant heat or radiation. Their emissivity is only 3 per cent. The surfaces of most building materials, including some insulations, have an absorptivity and emissivity of over 90 per cent for heat rays as against Infra's 3 per cent. CONDUCTION:--One sq ft of Type 6 Infra weighs only 1'A oz, has only 1)4 cu in. mass. The air-to-mass ratio of Infra by volume is 431 parts air to 1 part mass. For many insulations, when dry, it is only about 23 parts air to 1 part mass. CONVECTION and VAPOR:--Each of the 3 long, continuous, tough aluminum sheets of Infra has ZERO permeability to all gases, including heated air, cold air, and water vapor. Infiltration under flat stapled flanges is slight. The 2 fiber separators also retard CONVECTION. NON-CONDENSATION-FORMING:--The 3 aluminum sheets together with TWO inner accordion separators, which permanently prevent metal-to-metal contact, form FOUR inner rows of alternating, reflective air spaces. The construction, and the low heat storage capacity, minimize condensation formation on or within this type of insulation. ,. Infra Insulation uses 99,5 per cent pure aluminum, 0.0009 in. and 0.002 in. thick, made in accordance with special Infra emissivity requirements. It has 52 lbs and 17 lbs bursting strength (Mullen Test), 28 grams and 80 grams tearing strength (Elmen- dorf Test), which is up to 2600 per cent tougher than commonly used foils of less than 0.0005 in, thickness having up to 3 lb bursting and 10 gram tearing strengths. The special fiber separators are permanently flame, mold, and vermin resistant. FIRE:--Because its aluminum surfaces have very low emissivity (3 per cent) and a very high melting point (1220F), Infra has actually prevented the spread of fire. SANITARY.--Infra is sanitary, inhospi NOTE COMPLETE END TO END INSULATION table to vermin, and DOES NOT RE TAIN odors. Mechanics like to work with Infra. It is CLEAN, free of DUST or lint, with permanent freedom from floating particles. ' INFRA TYPE 4 JR. is half Q4) inch in depth. Can be used in 1 in. spaces be tween furring strips in brick or masonry walls; around metal ducts, etc. Write for a free copy of the sixth revised edition of "Simplified Physics of Vapor and Thermal Insulation," a manual by Alexander Schwartz, on the theory, practice and installation of insulation against heat and vapor flow and conden sation formation. 1602 Insulation Window Screens Ingersoll Products Division Borg-Warner Corporation 310 S. Michigan Ave., Chicago 4, 111. KoolShade* Sun screen is a bronze min iature Venetian blind- with fixed hori zontal louvers set at an angle which will keep the greatest possible amount of so lar heat load outside of windows. By reflecting, absorbing, and radiating most of the sun's heat rays outside the window, Koolshade keeps rooms up to 15 cooler and has been shown to accouot for as* much as 75% of the cooling necessary in air conditioning installations. Common measure: 100 sq ft of Koolshade is equal to 1 ton of refrigeration and costs to H as much. Koolshade provides insect pro tection equal to ordinary insect screen. Ingersoll franchised distributors apply Koolshade in rolled or extruded alumi num frames featuring the patented lacer wire that holds Koolshade in uniform tension. An Example! of cooling load reduction based on conditions prevailing at.peak solar load at 40 latitude: We have 16 windows on East side of building---each window 4 ft x- 6 ft for a total of 384 sq ft of window area. Use 10 a.m. Peak Load: Btu*8 Solar load transmitted through bare windows 116 Btu x 384 sqft................................. 44,544 Solar load transmitted through KoolShade 11.5 Btu x 384 sq ft.................................................... 4,416 Ingersoll KoolShade Expressed in tons of refrigeration (12,000 Btu's--1 Ton) Heat stoppage equals Tons 3.3444 Follow same procedure for 15 West Windows 4 ft x 6 ft--total square footage 360 sq ft--and using 3 p.m. Peak Load: Btu's Solar Load through Bare Windows 61,200 Solar Load through KoolShade 7,920 Reduction........................................ 537280 in Tons 4.440 Amount of Solar Heat stopped by KoolShade.................................... 40,128 South windows consist of 7--4 ft x 6 ft and 2--3 ft x 6 ft for total square footage of 204 sq ft--Figuring on 12 B0 noon Peak Load: , Btu's H 'fc f> !J h U U M, sUbsiuh *> i> uT s t, t, ;,~ij Enrrnl Solar Load through Bare Windows 15,096 Solar Load through KoolShade 1,224 Reduction........................................ 13,872 in Tons 1.156 Total tons of refrigeration saved 8.9404 A Sun Position, Heat Gain and Shading Data Calculator is available for architects and engineers. It is used for computing sun load on windows at various exposures at different times of the year in six different latitudes, N26 deg, 30 deg, 34 deg, 38 deg, 42 deg, and 46 deg . . . compiled in a slide chart for immediate reference. There is a nominal charge for this useful tool. Write for details to Ingersoll Products Division, Borg-Warner Corporation, Dept. V. t Example based on test data from ASHVE.GUIDE, 1964, pp. 287 through 299. ! Koolshade and Sungard are trademarks (Reg. U-S- Pat. Off.). They are the property of the InzersnU Steel Division, Borg-Warner Corp. 1603 Insulation Reflectal Corporation A Subsidary of Borg-Wamer Corp. 155East 44thStreet,New York 17,N.Y. ALFOL BUILDING BLANKET For more than 20 years--ever since the reflective principle was first introduced into America--architects, scientists and engineers have recognized ALFOL'S efficiency. From the famous Mount Palomar Observatory job of the 30's, to the huge housing projects of the 50's, ALFOL preference has been maintained. Throughout the years, ALFOL has always represented High Insulating Efficiency, Positive Vapor Barrier, Durability, Low Heat Storage Capacity, Low Cost. What ALFOL Is: Insulation consists of multiple aluminum foil sheets (A) that automatically space themselves on ap plication to form two, three or four re flective air spaces (B). The number of these spaces varies with ALFOL Type, but all types have a liner sheet of rugged, vapor-proof paper (C) that provides con-, tinuous moisture protection and positive application support. How ALFOL works: Radiant heat, as you know, normally accounts for 55 to 80 per cent of all heat loss through walls, roof or floor. Of all radiant heat, ALFOL foil sheets instantly, continu ously reflect 95 per cent (or emit but 5 per cent). And the captive air spaces between these foil surfaces curb heat loss through convection and conduction to check all forms of thermal loss! Practical advantages of ALFOL: Ther mal efficiency is the big factor, but there are other reasons for ALFOL leadership. Its heavy liner provides sag- and rip-re sisting application and a continuous vapor barrier. Its light weight Ofo lb/ sq ft) cuts rafter load. And ALFOL is as clean, odorless, durable as aluminum it self. Priced low. . .with compact design offering added savings in handling and application. . ALFOL is quick and easy to apply: You simply cut to length and staple across the faces of studs, joists or rafters. An ALFOL Type for every purpose: Type IV--4 reflective air spaces for top efficiency. 16 in., 20 in., 24 in. widths. Type III--3 reflective air spaces with foil base layer. 12 in., 16 in., 24 in. widths. Type II--3 reflective air spaces, our top seller! 12 in., 16 in., 20 in. widths. Type I--2 reflective air spaces. 12 in., 16 in., 24 in. widths. Type IA--2 reflective air spaces, for furred-out masonry. 16 in. widths only. All ALFOL Types immediately available in bandy 500 or 250 sq ft rolls. Write Dept. ASH for free data book. Other Outstanding ALFOL products ALFOL ASBESTOS: for central gas and oil heating equipment, water heaters, ranges, radiant heating seal and for all high temperature insulating requirements. ALFOL JACKETING: for refrigerator cars, trucks and other low temperature work. ALFOL PREFABRICATED PANELS: for tanks, towers and other precision jobs. 1604 ' Silvercote Products, Inc. 161 East Erie Street, Chicago, 111. SILVERCOTE* REFLECTIVE INSULATION Insulation Silvercote Heat Reflective Surfaces--The silver-like surface of Silvercote reflective insulation consists of a polished, heat reflective coating applied to a special kraft paper. The importance of using a Silvercote radiant heat reflective surface in modern building construction is obvious when it is realized that from 50 to 80 per cent of the heat transferred across a normal air space is in the form of radiation. REFLECTIVE SHEET INSULATIONS Silvercote Duplex--A thin flexible vapor barrier and insulation consisting of two sheets of Silvercote paper bonded to gether with asphalt. This material, con taining two exposed Silvercote surfaces, weighs approximately 50 lbs per thousand sq ft and is manufactured in 500 sq ft rolls in widths of 36 in. or 52 in. to span two 16 in. or 24 in. standard framing spaces. These widths permit bow-in of the Silvercote over the room side of the framing members to form an air space between the insulation and the interior finish. The water vapor permeability of Silvercote Duplex is 0.23 grains per sq ft per hour per inch of mercury vapor pressure difference. Silvercote Simplex--An economical vapor permeable reflective insulation designed for use where a vapor barrier is not re quired. Silvercote Simplex is a single sheet of special kraft paper coated on both sides noth the Silvercote surface. It weighs approximately 30 lbs per thou sand sq ft and is manufactured in 500 sq ft rolls in 36 in. or 52 in. widths to span two 16 in. or 24 in. standard framing spaces. These widths permit bow-in of the Silvercote over the exterior side of the framing members to form an air space between the insulation and the exterior sheathing. The water vapor perme ability of Silvercote Simplex fs 99.2 grains per sq ft per hour per inch of mercury vapor pressure difference. Silvercote In rolls distributed by: Bird & Son, Inc., and The Fllntkote Co. REFLECTIVE BLANKET INSULATIONS Blanket Insulation, Silvercote on Vapor Barrier Side--A popular building insula tion available in various thicknesses and faced on the vapor barrier side of the blanket with Silvercote paper. Manu facturers of this type of reflective blanket apply an asphalt coating to the back of the Silvercote paper for the twofold pur pose of bonding the insulation material to the Silvercote paper and to lend vapor resistant properties to the blanket at the room side of the insulation. Reflective. Blanket, Silvercote on Breather Sidey-This product was developed for application in structures where only one air space adjacent to the cold side of the blanket is available. Since Silvercote paper is a breather sheet it can be used on the breather side of a blanket with out perforating. Reflective Blanket, Silvercote on Both Sides.--A de luxe insulation material utilizing the full insulation value of blanket insulation, air spaces and two heat reflective surfaces. This double re flective blanket is manufactured with Silvercote Paper on the vapor barrier side and the breather side. AVAILABLE UPON REQUEST Silvercote's Handbook of "O" Values, 108 page illustrated booklet listing 12,852 "U" values of various walls, floors and ceilings--Silvercote's Handbook of "U" Values is unique in that it provides sum mer as well as winter "U" values. The Handbook's special listing of ceiling "U" values to indicate heat flow down char acteristics will be of interest to those who are concerned with summer comfort as well as winter fuel savings. Keg. U.S. Pat. Off. 1605 Publications American Society of Refrigerating Engineers 40 West 40th Street, New York'l8, N. Y. lished internationally on refrigeration and allied subjects. Four issues and an index annually at $7.00. APPLICATION DATA SECTIONS The APPLICATION DATA Sections tell precisely how refrigeration is used in various fields, giving examples and specific information on the best practice known to date. A complete list of the subjects covered is available on request. Some 23 bulletins are available sepa rately at reasonable prices for single copies or quantity orders and can also be had bound with a paper cover, the complete set for $4.00. CODES AND STANDARDS ONG acknowledged the most au- ASRE further contributes to refrigera L1 thoritative periodical in the field, tion progress by establishing codes and Refrigerating Engineering has added standards in the industry. These stand steadily to the practical value of its con ards cover approved methods for testing tents, and its number of readers has and rating various types of air condition grown in proportion. This magazine is a ing and refrigerating equipment. Also must for men who keep in touch with all included is the B-9 Safety Code for that is new and important in refrigera Mechanical Refrigeration. Sold sepa tion and air conditioning. The annual rately, or a complete set for $5.00. subscription price is $4. ASRE DATA BOOKS Published bi-annually since 1932, they now consist of two volumes, one issued each year. The Design Volume is a stand ard reference work containing funda mental data, refrigerant tables, descrip tion of the different cycles, systems, and component parts--a gold mine of in formation--$7.50 a copy. The Applications Volume is crammed full of how-it-is-done information on the use of refrigeration in 65 different applications. A must for the design or application engineer--$7.50 a copy. REFRIGERATION ABSTRACTS A Journal devoted to brief condensa tions, by specialists, of all articles of refrigerating interest appearing in hun dreds of periodicals and reports pub REFRIGERANT TABLES, CHARTS, AND CHARACTERISTICS A handy 6in. x9in. volume containing the thermodynamic properties of all re frigerants now in use, (reprinted from ASRE Data Book) forms a convenient reference for design and application engineers, contractors, professors and students. Cloth bound, $2.00, paper bound, $1.50. MEMBERSHIP ACTIVITIES T is the policy of the ASRE to treat I in its meetings current subjects touching upon all phases of the art of refrigeration. Membership is in several grades with dues from $10 to $20. Sec tions hold meetings in 35 priucipal cities. More detailed information will be sent on request. To keep apace with progress in refrigeration and air conditioning, read the publi cations and follow the activities of the AMERICAN SOCIETY OF REFRIGER ATING ENGINEERS, 40 West 40th St., New York 18, N. Y, 1606 Publications Coal-Heat Published at 20 W. Jackson Blvd., Chicago 4, Illinois Phone Wabash 2-9464 New York City, MUrray Hill 2-1647 . To Get the Facts about heating and fuel requirements, heating costs, operating and maintenance problems, the equipment situation, personnel, performance standards, fuel eco * nomics, sales and service--this is what we are trying to do, here at COAL-HEAT. 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: . 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, 160million tons of coal annually--the nation's largest fuel market, in either number of tons or customers. See "Heating-Fuel Markets"--$4.00 a copy. 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 ed ucational job--a job that rests largely on the retail dealer and the salesmen because they alone come in periodic contact with these 20-million fuel users. To help pro vide 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 de velop new business--these are the objectives of COAL-HEAT. It can help you get more business! FUEL AND HEATING EQUIPMENT--SALES AND SERVICE 1607 Publications Domestic Engineering Publications 1801 Prairie Avenue, Chicago 16, Illinois EFFECTIVE 2-WAY COVERAGE OF THE HEATING, PLUMBING AND AIR CONDITIONING FIELD DOMESTIC ENGINEERING MAGAZINE DOMESTIC ENGINEERING means leadership! Leadership in advertising . . . leadership in paid circulation . . . leadership in editorial content! DOMESTIC ENGINEERING won thirteen major national editorial achievement awards since 1939--a record unsurpassed by any business publication in this field. Editorial con tent is keyed high to attract and hold the reader loyalty of the top third who do eighty per cent of the business. These are inclusive contractor-dealers who sell and install broad lines of heating, air conditioning, plumbing and allied, productsr - DOMESTIC ENGINEERING serves their total business interests--manage ment, merchandising and technical. Published monthly. Yearly subscrip tion, U. S. and Canada, $5.00. Foreign, $8.00. DOMESTIC ENGINEERING CATALOG DIRECTORY DOMESTIC ENGINEERING CATA LOG DIRECTORY is one of the most comprehensive single sources of buying and specifying information for all types of products used in the heating, air con ditioning, plumbing and allied products industry. Listing virtually every known product in the field, this volume supplies also names and addresses, trade names and complete catalogs of leading manu facturers. Published annually. Price, $10.00 per copy. Together, DOMESTIC ENGINEER ING and DOMESTIC ENGINEERING CATALOG DIRECTORY constitute the backbone of every well-conceived pro motional program in this industry. To gether, they afford you effective two-way coverage of the important buying factors that make up this field. DOMESTIC ENGINEERING supplements these lead ing publications with a secondary pack age of services including market and research information, manufacturers' agents assistance, complete mailing facil ities and lists. Publications The Industrial Press 148 Lafayette Street, New York 13, N. Y. Telephone: Canal 6-8120 Heating and Ventilating Engineering magazine for the men who design systems and specify equipment This monthly engineering magazine (established 1904) is read by the engi neers--by whomever employed--who design, specify, install, and maintain sys tems for heating, ventilating, air condi tioning, piping, plumbing, industrial refrigeration, process steam, and related services. These systems are installed in . industrial plants, hospitals, office buildings, hotels, stores, schools, col leges, theaters, churches, institutions, government buildings, military installa tions, housing projects, etc. Readers include: Consulting engineers; engineers with architects, with large engineeringtype contractors, with utilities; engi neers with industrial plants and with large buildings; and others. To these men HEATING AND VENTILATING brings, month after month, a steady stream of crisply-written articles on the best current practice, boiled-down re search results, mathematical short-cuts, handy tables and charts, popular "H & V Data Sheets." Result: High reader interest that carries over to the ad vertising pages. Informative 24-page booklet, "How Equipment Is Bought," describes the market and specifying practices. Heating & Plumbing Equipment News The "new equipment" magazine serving Contractors and Wholesalers This monthly "new equipment" maga zine, published in tabloid format, reaches by controlled circulation 35,000 contractors, wholesalers and other groups concerned with the sale and in stallation of heating and plumbing equipment. Only publication that reaches all these categories: Radiator and warm-air heating contractors, oilburner dealers, gas-burner dealers, plumbing contractors, and the whole salers and distributors who supply all the foregoing. Editorial content con sists of concise, illustrated articles de scribing new and improved equipment, materials, and tools placed on the market,-also-new catalogs and' bulletins issued by manufacturers. Inquiries total over 100,000 per year for in formation about specific products such as: Boilers, furnaces, gas-burners, oilburners, toilets, sinks, pipe, fittings, valves, pumps, pipe-cutting and thread ing tools, hot water heaters, room coolers, water softeners, dishwashers, controls, insulation, and many others. Sample copy and advertising facts upon request. Subscription rales in U. S. and Canada; One year, $8; two years, $5; three yearst &6. In all other countries, $5 per year. 1609 KEENEY PUBLISHING COMPANY 6 North Michigan Avenue, Chicago 2, III. Publications Publications Sheet Metal Worker Published by Edwin A. Scott Publishing Corporation 92 Martling Ave., Tarrytown, N. Y. Heating, Piping and Air Conditioning AMERICAN ARTISAN covers the carries the Journal of the A.S.H.V.E. as field of warm air heating, residential air well as its own regular editorial section. conditioning, and sheet metal contract Its field is that of industry and large ing. Its readers are warm air heating buildings. It is devoted to the design, and sheet metal contractors, dealers, installation, operation, and mainte jobbers, manufacturers, and public util nance of heating, piping and air condi . ity companies. tioning systems in plants, commercial, Special features of each issue have institutional and public buildings. been devoted to air conditioning since Each January issue includes a com plete directory of commercial and indus trial heating, piping, and air condition ing equipment, which lists all products, their trade names, and the manufac turers* addresses. It is the established buying and specifying guide of the in dustry. H. P. & A. C. is read by consulting en gineers and architects . . . contractors . . . and engineers in charge of heating, piping and air conditioning in industrial plants, and other large buildings, fed eral, state, and city governments, school boards, and public utilities. All A.S. H.V.E. members are subscribers. Such coverage means, for the adver tiser, consideration at all points in the selling of a heating, piping, or air condi tioning product . . . consideration in its selection during the preparation of plans 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 conditioning-- supplied through forced warm air heat ing 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 a com plete directory of residential air condi tioning, 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 residential air con ditioning picture is the warm air heating and specifications; in its actual purchase for installation; in its year-'round buy ing for operating and maintenance re quirements. Without waste, the manu facturer of air conditioning products and equipment can reach through H. P. & A. C. those from whom he is seeking the necessary engineering acceptance. and sheet metal contractor--the one man experienced in "treating air'* at a cen tral place and getting it properly dis tributed. And American Artisan is the key publication--because it ' reaches these key men with information that has made it the recognized authority on residential air conditioning practice. Member--A.B.P.--A .B.C. Member--A.B.P.--.4 .B.C. Subscription Prices--U. S. $$ per year. Subscription Prices--U.S. $S per year. Canada, Spain, Central and So. America--$4.00 per year Elsewhere $6 per year. 1610 Subscription rates--U.00 per year, U. S., Canada and Pan A mer. Foreign $5.00. A dverUsing rates on request. rTiHE January 1954 issue of Sheet Metal Worker was its 80th Anniversary and X Directory Number. It is the oldest publication in its field and is of vital im portance to men interested in sheet metal work--air conditioning--warm-air heat ing and ventilation. Founded in 1874 and published to 1909 by David Williams Company; 1909 to 1920 by United Publishers Corp.; since 1920, by the Edwin A. Scott Publishing Corporation. Subscribers are mainly merchandising contractors purchasing practically all products and equipment which they fabricate, erect or install. Manufacturers, jobbers and distributors also subscribe. The market has threemain divisions: (1) Equipment for resale in connection with erection or installation work. (2) Materials for fabrication. (3) Shop equipment and supplies. Circulation: Sheet Metal Worker is a member of Controlled Circulation Audit, Inc. Nearly 10,000 contractors are covered. Sheet Metal Worker also publishes books on heating, ventilating, sheet metal work, air.conditioning, etc. The Annual Issue published in January, contains a comprehensive and valuable Directory Section. Plumbing and Heating Journal Scott-Choate Publishing Company, Inc., Publishers 92 Martling Ave., Tarrytown, N, Y. LUMBING and Heating Journal is edited to furnish a well-rounded, efficient Pservice to the men engaged in the plumbing, heating, ventilating and air con ditioning fields. It covers both the technical and business phases of their work. It gives free technical service through a staff of practical engineers; expert mer chandising assistance, and its technical and business articles are by men of recog nized competence. THE JOURNAL editorial department draws its news from scores of trained cor respondents located at strategic points throughout the country. This combination of the technical, business, news and other aspects of the indus try enables THE JOURNAL to achieve a finely balanced magazine that gives the reader the type of information he wants and needs, in brief, compact form. A department. "With the Water Systems,** informs the trade of the latest develop ments in the rural plumbing field and its increasing potentialities for the plumbing --heating contractor, especially with the recent extensions of rural electric lines throughout the country. 1611 Publications Snips Magazine 5707 W. Lake St. Chicago 44, 111. The Real Push Behind Sales PREFERRED as an effective advertis ing medium by many notable industrial advertisers year after year, and many Prominent Jobbers who know their market well. During the past year over 400 firms used space with us. These valued patrons see in our 14,574 readers, a carefully selected and substantial buying group, worthy of "talking to" month after month. SNIPS is packed each month, from cover to cover, with hundreds of live news stories and exclusive pictures in cluding practical applications of latest advancements of the Sheet Metal, Heat ing, Air Conditioning and Ventilation trade. No long contributed stories. It's all field gathered material, secured the hard way, rubbing shoulders with the readers. Such work gets for the periodi cal a reader interest seldom found in a trade publication. You'll find this feature the basis of the sensational inquiry pulling power and sales producing value of advertising space in SNIPS. Rates for space have always been con servative. The carefully figured current rate with cream coverage available at the extremely low rate per thousand distribution is truly an exceptional value at this time. January Annual & BJjnteb Market Number--March Annivebsakt Spring Market Issue--September Fall Market Issue--December Holiday Greeting Issue--Further information gladly sent on request. 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 in stalling concerns whom the principal jobbers and distributors of the industry --people who really know their territor ies best--consider worthy of cultivation by mail, promotion and salesmen's calls. These advertising people always alert to serve you: H. F. Hoy, Nick Carter, and Ed Carter in the Home Office. In the East, Snips Magazine, 141 East 44th Street, New York 17, New York, MUrray Hill 2-1647. In the West, Maurice A. Kimball Co., 2550 Beverly Blvd., Los Angeles 4, California, DUnkirk 8-6178, and Rm. 767, 681 Market St., San Francisco 5, Calif., EXbrook 2-3365. 1612 ENGINEERS OF HUMAN COMFORT The Heating, Ventilating and Air Conditioning Engineers through their work and research bring to our homes, schools, offices, factories, theaters, hospitals and other public buildings in both summer and winter, that climaie best suited to our comfort and health. These men realize the basic importance of heating and ventilating as a primary element in the well-being of civilized mankind, living and working mostly indoors. They are truly Engineers of Human Comfort. Started in 1894, by a small but progressive group, The American Society ot Heating and Ventilating Engineers now numbers over 9400 members, whose express purpose is to improve the Art through the interchange of ideas and the stimulation of scientific research and invention. The Society membership now includes engineers, educators, scientists, physicians, architects, contractors, and leaders of industry. Membership consists of Charter, Honorary, Life, Presidential, Member, Associate, Junior, Affiliate and Student grades. The management of the Society is entrusted to 4 Officers and a Council of 13 elected members. Continuity of policy is insured by electing 4 men annually for a 3-year term and retaining the retiring president of the Council for I year. Two national meetings are held each year--the Annual Meeting during January or February, and the Semi-Annual Meeting usually in June or July. . The three major activities of the Society are: Membership service. Publication, and Research, the record of its accomplishments being permanently recorded in the annual Transactions. Headquarters of the Society are maintained at 62 Worth St., New York 13, N. Y., and its research laboratory, devoted to the study of fundamental principles of heatAg, ventilating and air conditioning, is located at 7218 Euclid Ave., Cleveland 3, Ohio. In September, 1894, a little group of nationally known engineers, educators and manufacturers gathered in New York and agreed that the great art of heating and ventilating deserved and required recognition as an essential, distinctive and highly specialized division of modern engineering. These keen, alert, progressive men knew that the methods and equipment of their day could be improved, even beyond their own vision, if all the personalities striving for such improvement could be welded into one organized cooperative group imbued with the same ideals and aiming for the same goal. They therefore formed them selves into the nucleus of such an organization and called it The American Society of Heating and Ventilating Engineers. Foreseeing the need for research they made it one of their first acts to establish a Committee on Standards. That the Charter Members had great faith in their enter prise is evident, although little did they dream that progress would be so rapid in their profession. During the intervening years, since that little group of 75 pioneers unfurled the banner of The American Society of Heating and Ventilating Engineers, thou sands of the real leaders of thought and action in heating, ventilating, and air con ditioning have gathered about that standard and carried it proudly before them far along the way of outstanding accomplishment. They may be identified among engi neering groups by the distinctive emblem which was adopted by the Charter Members. . The first Annual Meeting was held in New York, N. Y., January 22-24, 1895, and . the organization was incorporated that same year, under the laws of the State. 1613 /' A. S. H. V. E. RESEARCH LABORATORY Since 1919 The American Society op Heating and Ventilating Engineers has maintained a permanent research staff and, since 1946, its own research laboratory at 7218 Euclid Ave.^Cleveland 3, Ohio, devoted to the study of fundamental problems in the field of heating, ventilating and air conditioning. 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 educational institu tions of the United States and Canada. All research activities are planned and supervised by the Committee on Research of 15 elected members, assisted by various Technical Advisory Committees of the Society. Since 1919, close to $2,000,000 has been expended on research, which has helped guide the industry to better practice and equipment. Together with the co operating institutions the Society has, during the past year, conducted 34 research ' projects including work on Panel Heating and Cooling, Solar Heat Gain and Shading Effects, Air Distribution, etc. 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 contributions from friends in the industries en gaged in the general field of heating, ventilating and air conditioning. MEETINGS OF The American Society of Heating and Ventilating Engineers Year 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 Annual Meeting 1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th 11th 12th 13th 14th 15th 16th Date 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 Jan. 17-19 Jan. 16-18 Jan. 22-24 Jan. 21-23 Jan. 19-21 Jan. 18-20 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 17th 18th 19th 2Cth 21st 22nd 23rd 24th 25th 26th 27th 28th Jan. 24-26 Jan. 23-25 Jan. 21-23 Jan. 20-23 Jan. 20-22 Jan. 18-20 Jan. 16-18 Jan. 22-24 Jan. 28-30 Jan. 27-29 Jan. 26-28 Jan. 24-26 1923 29th Jan. 23-26 1924 30th Jan. 22-25 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. 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. jSm-Annuoi Medina None None June 18 July 15 None None July 12-13 June 16 July 17-18 July 15-16 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 June 6-7 June 8-10 May 21-23 June 19-22 1614 Place New York, N. Y. Atlantic City, N. J. Chicago, 111. Atlantic City, N. J. Niagara Falls, N. Y. Detroit, Mich. Chicago, 111. Chicago, 111. 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, 111. Buffalo, N. Y. Pittsburgh, Pa. ' St. Louis, Mo. Cleveland, Ohio Buffalo, N. Y. Detroit, Mich. Chicago, 111. Kansas City, Mo. Year 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 Annuo! Meeting 31st Date Jan. 27-30 32nd Jan. 26-29 33rd Jan. 26-28 34th 35th 36th 37th 38th 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. 23-26 46th Jan. 23-26 47th 48th 49th 50th 51st 52nd Jan. 27-29 Jan. 26-28 Jan. 25-27 Jan. 31- Feb.1-2 Jan. 22-24 Jan. 27-30 53rd 54th 55th 56th 57th 58th 59th Jan. 27-30 Feb. 2-5 Jan. 24-27 Jan. 23-26 Jan. 22-25 Jan. 28-30 Jan. 26-29 60th Jan. 25-27 ' Place New York, N. Y. and Boston Buffalo, N. Y. St. Louis, Mo. .Semi-Annual . Meeting June 15-17 May 26-28 June 28-30 New York, N. Y. June 26-29 Chicago, 111. June 26-28 Philadelphia, Pa. June 24-27 Pittsburgh; Pa. June 22-25 Cleveland, Ohio June 27-29 Cincinnati, Ohio June 22-24 New York, N. Y. June 20-22 Buffalo, N. Y. June 16-19 Chicago, 111. June 22-24 St. Louis, Mo. June 24-26 New York, N. Y. June 20-23 Pittsburgh, Pa. July 4-6 *Oct. 30-31 Cleveland, Ohio June 17-19 Oct. I4r-l5 Kansas City, Mo. June 17-19 Philadelphia, Pa. June 15-17 Cincinnati, Ohio June 7-8 New York, N. Y. June 19-20 Boston, Mass. New York, N. Y. June 10-13 Cleveland, Ohio New York, N. Y. Chicago, 111. Dallas, Tex: Philadelphia, Pa. St. Louis, Mo. Chicago, 111. Houston, Tex. June 1-4 June 20-23 June 20-22 June 19-21 July 2-4 June 16-18 June 29-30, July 1 ' Place Atlantic City, N. J. Lexington, Ky. White Sulphur Springs . 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, Minn. Muskoka Lakes, Ont. Portland, Ore. Spring Lake, N. J. Denver, Colo. * Fall Meeting- PRESIDENTS OF THE A.S.H.V.E. * 1954--Louis N. Hunter 1953--Reg. F. Taylor 1952--Ernest Szekely 1951--Lauren E. Seeley 1950--Lester T. Avery 1949--A. E. Stacey, Jr. 1948--G. L. Tuve 1947--Baldwin M. Woods 1946--Alfred J. Offner 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. McIntibe 1938--E. Holt Gurney 1937--D. S. Boyden 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--Homer 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 Macejiy 1907--C. B. J. Snyder 1906--John Gormly 1905--William Kent 1904--Andrew Harvey 1903--H. D. Crane 1902--A. E. Kenrick 1901--J. H. Kinealy 1900--D. M. Quay 1899--Henry Adams 1898--Wiltsie F. Wolfe 1897--Wm. M. Mackay 1896--R. C. Carpenter 1895--Stewart A. Jellett 1894--Edward P. Bates 1615 President...................... First Vice President .. Second Vice President Treasurer.................. ... Executive Secretary... OFFICERS ...........L. N. Hunteb . .John E. Haines .. .John W. James ......... E. R. Queer A. V. Hutchinson Technical Secretary............................................................................................................................ Cabl H, Funk Assistant Secretary........................................................................................ .................................D. T. Donovan COUNCIL L. N. Hunteb, Chairman John E. Haines, Vice Chairman Three years: John H. Fox, Abthub J. Hess, C. H. Pestebfield, Benjamin H. Spurlock, Jb. . Two years: I. W. Cotton, A. W. Edwabds, L. T. Mabt, B. W. Fabnes (one- year). . One year: M. K. Fahnestock, P. B. Gordon, R. T. Kebn, D. M. Miles, Reg. F. Taylor ADVISORY BOARD Reg. F. Taylor, Chairman; Lester T. Avery, M. F. Blankin, S. E. Dibble, S. H. Downs, E. 0. Eastwood, W. L. Fleisher, H. P. Gant, E. Holt ' Gurney, H. M. Hart, C. V. Haynes, D, D. Kimball, S. R. Lewis, A. J. E. E.Offner, F. B. Rowley, L. Seeley, A. Stacey, Jr., Ernest Szekely, G. L. Tuve, A. C. Willard, C.-E. A. Winslow and B. M. Woods. COUNCIL COMMITTEES Executive: John E. Haines, Chairman; John W. James, E. R. Queer. . Subcommittee: H. E. Sproull, Chairman; E. L. Crosby, G. W. F. Myers. Finance: John W. James, Chairman; A. J. Hess, L. T. Mart, E. R. Queer, Ex-Officio. Membership: D. M. Mills, Chairman; I. W. Cotton, J. H. Fpx. Program and Papers: B. H. Spurlock, Jr., Chairman; R. T. Kern, C. H. Pester- field. COMMITTEE ON RESEARCH R. S. Dill, Chairman B. H. Jennings, Vice Chairman C. M. Humphreys, Acting Director of Research Three years: John Everetts, Jr., W. F. Friend, Carl F. Kayan, H. R. Limbacher, E. F. Snyder, Jb. gy Shears; R. S. Dill, F. H. Faust, R. W. Keeton, M.D., H. A. Lockhart, " ' McElgin. 11. W. Cotton, W. A. Grant, N. B. Hutcheon, B. H. Jennings, C. O. Iey. 1616